ScienceBlogs - Where the world discusses science en Appreciating van Leeuwenhoek: The Cloth Merchant Who Discovered Microbes <span>Appreciating van Leeuwenhoek: The Cloth Merchant Who Discovered Microbes</span> <div class="field field--name-body field--type-text-with-summary field--label-hidden field--item"><p>Imagine trying to cope with a pandemic like COVID-19 in a world where microscopic life was unknown. Prior to the 17th century, people were limited by what they could see with their own two eyes. But then a Dutch cloth merchant changed everything.</p> <p>His name was Antonie van Leeuwenhoek, and he lived from 1632 to 1723. Although untrained in science, Leeuwenhoek became the greatest lens-maker of his day, discovered microscopic life forms and is <a href="">known today as the “father of microbiology.”</a></p> <h2>Visualizing ‘animalcules’ with a ‘small see-er’</h2> <p><img alt="Antonie van Leeuwenhoek" data-entity-type="file" data-entity-uuid="066d213f-6e51-446d-aa60-b5b9bf1fd3bc" src="/files/inline-images/van%20Leeuwenhoek.jpg" /></p> <p><span>Leeuwenhoek opened the door to a vast, previously unseen world.</span> <span><a href="">J. Verolje/Wellcome Collection</a>, <a href="">CC BY</a></span></p> <p>Leeuwenhoek didn’t set out to identify microbes. Instead, he was trying to assess the quality of thread. He developed <a href="">a method for making lenses</a> by heating thin filaments of glass to make tiny spheres. His lenses were of such high quality he saw things no one else could.</p> <p>This enabled him to train his microscope – literally, “small see-er” – on a new and largely unexpected realm: objects, including organisms, far too small to be seen by the naked eye. He was the <a href="">first to visualize red blood cells, blood flow in capillaries and sperm</a>.</p> <p><img alt="van Leeuwenhoek bacteria" data-entity-type="file" data-entity-uuid="72b6ea41-0f2e-48be-8a86-e965cd62a749" src="/files/inline-images/van%20Leeuwenhoek%20bacteria.jpg" /></p> <p><span>Drawings from a Leeuwenhoek letter in 1683 illustrating human mouth bacteria.</span> <span><a href="">Huydang2910</a>, <a href="">CC BY-SA</a></span></p> <p>Leeuwenhoek was also the <a href="">first human being to see a bacterium</a> – and the importance of this discovery for microbiology and medicine can hardly be overstated. Yet he was reluctant to publish his findings, due to his lack of formal education. Eventually, friends prevailed upon him to do so.</p> <p>He wrote, “Whenever I found out anything remarkable, I thought it <a href="">my duty to put down my discovery on paper</a>, so that all ingenious people might be informed thereof.” He was guided by his curiosity and joy in discovery, asserting “I’ve taken no notice of those who have said <a href="">why take so much trouble and what good is it</a>?”</p> <p>When he reported visualizing “animalcules” (tiny animals) swimming in a drop of pond water, members of the scientific community questioned his reliability. After his findings were <a href="">corroborated by reliable religious and scientific authorities</a>, they were published, and in 1680 he was invited to join the Royal Society in London, then the world’s premier scientific body.</p> <p>Leeuwenhoek was not the world’s only microscopist. In England, his contemporary <a href="">Robert Hooke coined the term “cell”</a> to describe the basic unit of life and published his “Micrographia,” featuring incredibly detailed images of insects and the like, which became the first scientific best-seller. Hooke, however, did not identify bacteria.</p> <p>Despite Leuwenhoek’s prowess as a lens-maker, even he could not see viruses. They are about 1/100th the size of bacteria, much too small to be visualized by light microscopes, which because of the physics of light <a href="">can magnify only thousands of times</a>. Viruses weren’t visualized until 1931 with the <a href="">invention of electron microscopes</a>, which could magnify by the millions.</p> <p><img alt="microscope dots" data-entity-type="file" data-entity-uuid="69e14bc5-2ddc-44ee-b849-202d13604df6" src="/files/inline-images/microscope%20dots.jpg" width="600" /></p> <p><span>An image of the hepatitis virus courtesy of the electron microscope.</span> <span><a href="">E.H. Cook, Jr./CDC via Associated Press</a></span></p> <h2>A vast, previously unseen world</h2> <p>Leeuwenhoek and his successors opened up, by far, the largest realm of life. For example, all the bacteria on Earth <a href="">outweigh humans by more than 1,100 times</a> and outnumber us by an unimaginable margin. There is fossil evidence that <a href="">bacteria were among the first life forms on Earth</a>, dating back over 3 billion years, and today it is thought the planet houses about <a href="">5 nonillion (1 followed by 30 zeroes) bacteria</a>.</p> <p>Some species of <a href="">bacteria cause diseases</a>, such as cholera, syphilis and strep throat; while <a href="">others, known as extremophiles</a>, can survive at temperatures beyond the boiling and freezing points of water, from the upper reaches of the atmosphere to the deepest points of the oceans. Also, the number of harmless bacterial cells on and in our bodies <a href="">likely outnumber the human ones</a>.</p> <p>Viruses, which include the coronavirus SARS-CoV-2 that causes COVID-19, outnumber bacteria by a factor of 100, meaning there are <a href="">more of them on Earth than stars in the universe</a>. They, too, are found everywhere, from the upper atmosphere to the ocean depths.</p> <p><img alt="human rhinovirus" data-entity-type="file" data-entity-uuid="3bdc2455-4b6e-4d4d-a118-63b60bd4980f" src="/files/inline-images/human%20rhinovirus.png" width="600" /></p> <p><span>A visualization of the human rhinovirus 14, one of many viruses that cause the common cold. Protein spikes are colored white for clarity.</span> <span><a href="">Thomas Splettstoesser</a>, <a href="">CC BY-SA</a></span></p> <p>Strangely, <a href="">viruses probably do not qualify as living organisms</a>. They can replicate only by infecting other organisms’ cells, where they hijack cellular systems to make copies of themselves, sometimes causing the death of the infected cell.</p> <p>It is important to remember that microbes such as bacteria and viruses do far more than cause disease, and many are vital to life. For example, <a href="">bacteria synthesize vitamin B12</a>, without which most living organisms would not be able to make DNA.</p> <p>Likewise, viruses cause diseases such as the common cold, influenza and COVID-19, but they also play a vital role in transferring genes between species, which <a href="">helps to increase genetic diversity and propel evolution</a>. Today <a href="">researchers use viruses to treat diseases such as cancer</a>.</p> <p>Scientists’ understanding of microbes has progressed a long way since Leeuwenhoek, including the development of antibiotics against bacteria and vaccines against viruses including SARS-CoV-2.</p> <p>But it was Leeuwenhoek who first opened people’s eyes to life’s vast microscopic realm, a discovery that continues to transform the world.</p> <p><img alt="richard gunderman" data-entity-type="file" data-entity-uuid="bd77d23b-60b5-498c-b603-0d41c6c5c70a" src="/files/inline-images/richard-gunderman.png" /></p> <p>By <a href="">Richard Gunderman</a>, Chancellor's Professor of Medicine, Liberal Arts, and Philanthropy, Indiana University. This article is republished from <a href="">The Conversation</a> under a Creative Commons license. Read the <a href="">original article</a>.</p> <p> </p></div> <span><a title="View user profile." href="/author/sb-admin" lang="" about="/author/sb-admin" typeof="schema:Person" property="schema:name" datatype="">sb admin</a></span> <span>Tue, 04/06/2021 - 10:49</span> <div class="field field--name-field-blog-categories field--type-entity-reference field--label-inline"> <div class="field--label">Categories</div> <div class="field--items"> <div class="field--item"><a href="/channel/life-sciences" hreflang="en">Life Sciences</a></div> </div> </div> Tue, 06 Apr 2021 14:49:13 +0000 sb admin 151456 at The Increase in Infant Milk Formulas and Why It Matters <span>The Increase in Infant Milk Formulas and Why It Matters</span> <div class="field field--name-body field--type-text-with-summary field--label-hidden field--item"><p><a href="">Breastfeeding</a> can play an especially important role in early-life nutrition. It can <a href="">benefit</a> children’s future school performance and economic prospects in later life, as well as the mother’s health.</p> <p>Health authorities across the world endorse the World Health Organization’s (WHO) <a href="">recommendation</a> that newborns should where possible exclusively breastfeed from the first hour of life until six months of age, and thereafter receive safe and nutritious foods with continued breastfeeding up to two years of age or beyond.</p> <p>Despite this, our <a href="">recent study</a> shows that global commercial milk formula sales are booming. Between 2005 and 2019, world milk formula sales more than doubled from 3.5kg to 7.4kg per child. Total sales grew from 1 million tonnes to 2.1 million tonnes.</p> <p>This growth in sales was seen in all types of formula, including “standard” formula for infants (0-6 months), “follow-up” formula (7-12 months), toddler milks (13-36 months), and so-called “specialised” formulas. So more children from a wider range of age groups are consuming formula.</p> <p>Rapid growth <a href="">has occurred</a> in many highly-populated countries, including the Middle East, north Africa, eastern Europe, central Asia, and parts of Latin America. The most remarkable growth has been in east and south-east Asia. China, in particular, accounted for only 14% of global formula sales in 2005 – but now accounts for 33% of all sales.</p> <p>In south Asia and west and central Africa, the amount sold to each customer remains low and show no signs of growth. In Europe and North America, although per customer sales volumes remain high, they plateaued or slightly decreased between 2005-2019.</p> <p><img alt="Infant formula sare booming" data-entity-type="file" data-entity-uuid="56a1e646-83ab-4157-92be-1136ed75b22a" src="/files/inline-images/infant%20formula.jpg" /></p> <p>Infant formula sales have doubled between 2005 and 2019. <span><a href="">279photo Studio/ Shutterstock</a></span></p> <h2><a href="">Behind the sales ‘boom’</a></h2> <p><a href="">There are </a><a href="">medical reasons</a> for using safe and adequate breastmilk substitutes. And some women find continuing breastfeeding difficult depending on their circumstances, and may use formula as an alternative or complement to breastfeeding. <a href="">Our study</a> also shows decisions and practices around formula use can be strongly shaped by wider societal forces, such as commercial marketing, rather than individual choice.</p> <p>It’s known that milk formula sales increase as countries become richer and more urbanised, and as more mothers enter into formal employment. Asia’s formula sales boom may be partly explained by millions of women entering the paid workforce, especially in the region’s vast manufacturing zones.</p> <p>Millions of women worldwide also lack adequate <a href="">paid maternity leave and social protection</a>. This means the decision to formula feed may only be done out of necessity, to avoid losing employment and income. We also know that many hospitals and healthcare settings aren’t equipped to help women establish breastfeeding, with few maternal and newborn care facilities worldwide meeting <a href="">standards</a> of care for breastfeeding mothers and newborns.</p> <p>Commercial factors are also important. Just five companies control 57% of the global formula milk industry, worth US$56.6 billion (£42.5 billion) The industry spends <a href="">an estimated US$5 billion on marketing every year</a>, which <a href="">powerfully shapes social norms</a> about <a href="">feeding babies and children</a>.</p> <p>Marketing messages can portray formula as modern, scientific and comparable or superior to breastmilk. The growth of social media enables companies to <a href=",a%20brand%20and%20generic%20level.">target mothers</a> with personalised product offerings and ads.</p> <p>Hospitals are a key marketing channel, too. Companies often engage health professionals to promote formula feeding. In many countries, health professionals are directly compensated to promote formula. But more commonly, companies influence health professionals indirectly by <a href="">sponsoring</a> their associations, conferences and education.</p> <p><img alt="A grocery store aisle full of baby and toddler formula products." src=";q=45&amp;auto=format&amp;w=754&amp;fit=clip" /></p> <p><span>Companies cross-promote products by using the same packaging.</span> <span><a href="">ValeStock/ Shutterstock</a></span></p> <p>Companies also <a href=",to%20breastfeeding%20and%20infant%20health.&amp;text=As%20a%20result%2C%20young%20infants,cannot%20meet%20their%20nutritional%20needs.">cross-promote</a> their entire product range of follow-up and toddler milks by using packing and labelling that resembles standard infant formula. This allows companies to get around the stricter prohibitions on infant formula marketing.</p> <p>Marketing regulations are also important. The fact that formula sales are booming in China but have flat-lined at low levels in India partly reflects contrasting regulatory environments – with regulations on marketing being stricter and more comprehensive in India.</p> <p>Despite <a href="">an international code</a> to stop <a href="">aggressive and inappropriate marketing</a> of breast-milk substitutes, most governments haven’t fully incorporated it <a href="">into law</a>. And even when laws exist, marketing violations by formula companies often go unpunished. The formula industry has also been able to lobby against any strengthening of regulation, partly by promoting their own – much weaker – corporate policies on marketing.</p> <h2>Health concerns</h2> <p>Breastmilk and breastfeeding where it is possible has numerous advantages over formula and bottle feeding – which is why the growth of formula sales is concerning.</p> <p>Breastfeeding has been shown to reduce the likelihood of children developing infections, and reduces a child’s risk of <a href=",type%20II%20diabetes%20each%20year">developing chronic disease like obesity and diabetes</a> later in life. Breastfeeding is also associated with lower risk of developing <a href="">breast and cervical cancer, or diabetes</a> among mothers.</p> <p>Rising consumption of formula milk by toddlers and young children is also a worry, as these products are often <a href=",%2C%20salt%20and%20trans%2Dfats.">ultra-processed</a>, expensive, loaded with sugar and can introduce <a href="">poor dietary habits</a>. Their increased use could further contribute to increases of overweight and obese children globally.</p> <p>Formula isn’t a sterile product and can be dangerous when prepared in unhygienic conditions, or when over-diluted or over-concentrated. It lacks the immune-boosting and other important elements of breastmilk, further increasing the risk of malnutrition and infectious illness. As a result, universal breastfeeding in place of formula use could prevent an estimated <a href="">823,000 child deaths every year</a> (mainly in low- and middle-income countries), including 595,000 deaths from diarrhoea and pneumonia, and an estimated 20,000 maternal deaths from breast cancer (mainly in high income countries).</p> <p>The global surge in formula sales is clearly a problem for global health. Given the power of the corporate milk formula industry to influence behaviour and understanding, more needs to be done to ensure that all mothers and children are protected from inappropriate promotion, and that they are enabled to breastfeed as long as they want to. This means <a href="">strengthening laws</a> that ban harmful marketing practices, expanding access to paid maternity leave, and ensuring that all <a href="">healthcare facilities</a> meet global standards.<img alt="The Conversation" height="1" src="" width="1" /></p> <p><span><a href="">David McCoy</a>, Professor of Global Public Health, <em><a href="">Queen Mary University of London</a></em>; <a href="">Julie P. Smith</a>, Honorary Associate Professor, <em><a href="">Australian National University</a></em>, and <a href="">Phillip Baker</a>, Research Fellow, Institute for Physical Activity and Nutrition, Deakin University, <em><a href="">Deakin University</a></em></span></p> <p>This article is republished from <a href="">The Conversation</a> under a Creative Commons license. Read the <a href="">original article</a>.</p></div> <span><a title="View user profile." href="/author/sb-admin" lang="" about="/author/sb-admin" typeof="schema:Person" property="schema:name" datatype="">sb admin</a></span> <span>Mon, 12/07/2020 - 18:21</span> <div class="field field--name-field-blog-categories field--type-entity-reference field--label-inline"> <div class="field--label">Categories</div> <div class="field--items"> <div class="field--item"><a href="/channel/social-sciences" hreflang="en">Social Sciences</a></div> </div> </div> Mon, 07 Dec 2020 23:21:44 +0000 sb admin 151455 at Greenland Could Lose Ice Faster Than Any Century Since The Last Ice Age Ended <span>Greenland Could Lose Ice Faster Than Any Century Since The Last Ice Age Ended</span> <div class="field field--name-body field--type-text-with-summary field--label-hidden field--item"><p>A new estimate using sheet modeling finds that Greenland's rate of <a href="">ice loss this century could outpace that of any century over the past 12,000 years</a>, when the last Ice Age ended.</p> <p>Scientists used reconstructions of ancient climate to drive the model, and validated the model against real-world measurements of the ice sheet's contemporary and ancient size.</p> <p>The study brought together climate modelers, ice core scientists, remote sensing experts and paleoclimate researchers. The team used an ice sheet model to simulate changes to the southwestern sector of the Greenland Ice Sheet, starting from the beginning of the Holocene epoch 12,000 years ago and extending forward 80 years to 2100. Data came from ice cores to create maps of temperatures and precipitation in the study region that were used to drive the ice sheet model simulations up to the year 1850 while other published climate data were used to drive the simulations after that date.</p> <figure role="group"><img alt="Infographic describing the study's findings. Image: Bob Wilder / University at Buffalo" data-entity-type="file" data-entity-uuid="17c5924d-9b90-40e6-bfd0-47cde566b673" src="/files/inline-images/Greenland%20is%20on%20track%20to%20lose%20ice.jpg" width="700" /><figcaption>Infographic describing the study's findings. Image: Bob Wilder / University at Buffalo</figcaption></figure><p>Scientists tested the model's accuracy by comparing results of the model's simulations to historical measurements. The modeled results matched up well with data tied to actual measurements of the ice sheet made by satellites and aerial surveys in recent decades, and with field work identifying the ice sheet's ancient boundaries. </p> <p>"We built an extremely detailed geologic history of how the margin of the southwestern Greenland Ice Sheet moved through time by measuring beryllium-10 in boulders that sit on moraines," <a href="">says co-author Nicolás Young</a>, PhD, associate research professor at LDEO. "Moraines are large piles of debris that you can find on the landscape that mark the former edge of an ice sheet or glacier. A beryllium-10 measurement tells you how long that boulder and moraine have been sitting there, and therefore tells you when the ice sheet was at that exact spot and deposited that boulder. Amazingly, the model reproduced the geologic reconstruction really well. This gave us confidence that the ice sheet model was performing well and giving us meaningful results. You can model anything you want and your model will always spit out an answer, but we need some way to determine if the model is doing a good job."</p> <p>Though the project focused on southwestern Greenland, research shows that changes in the rates of ice loss there tend to correspond tightly with changes across the entire ice sheet. </p> <p> </p></div> <span><a title="View user profile." href="/author/sb-admin" lang="" about="/author/sb-admin" typeof="schema:Person" property="schema:name" datatype="">sb admin</a></span> <span>Wed, 09/30/2020 - 14:38</span> <div class="field field--name-field-blog-categories field--type-entity-reference field--label-inline"> <div class="field--label">Categories</div> <div class="field--items"> <div class="field--item"><a href="/channel/physical-sciences" hreflang="en">Physical Sciences</a></div> </div> </div> Wed, 30 Sep 2020 18:38:02 +0000 sb admin 151454 at Fork-Tailed Flycatchers Make Sounds With Their Feathers in Different Accents <span>Fork-Tailed Flycatchers Make Sounds With Their Feathers in Different Accents</span> <div class="field field--name-body field--type-text-with-summary field--label-hidden field--item"><p>(Inside Science) -- The fork-tailed flycatcher whistles with its wings in two different accents, potentially more evidence this bird is splitting into two species, a new study finds.</p> <p>Birds are known for the songs they can sing, but dozens of species also use their feathers to generate sounds. For instance, peacocks can rattle their quills together, and <a href="">the crested pigeon's wings whistle when they fly</a>.</p> <p>In the new study, researchers investigated fork-tailed flycatchers -- 1-ounce birds found throughout the Americas that resemble black-and-gray swallows. The males sport foot-long scissor-shaped tails as ornaments to help attract mates, and they also spread these giant feathers to help turn sharply while hunting by using the plumes as air brakes, said study lead author Valentina Gómez-Bahamón, an evolutionary biologist at the Field Museum in Chicago.</p> <p>When these birds fly -- sometimes as fast as 65 miles per hour -- they produce a high-pitched trill. Males often fly quickly when they fight each other during mating season, Gómez-Bahamón noted. The birds also fly quickly when fighting off intruders near their nests.</p> <p>The scientists studied two known subspecies of fork-tailed flycatchers: a migratory one that breeds in the southern part of South America but spends winter closer to the equator, and a nonmigratory one that spends the whole year in the northern part of the continent.</p> <p>The scientists first captured the birds with "mist nets" -- fine webbing stretched between two poles like a volleyball net -- and recorded audio and video of them as they flew away after they were released. The researchers also set up a taxidermy hawk in a field with a hidden camera, and when the fork-tailed flycatchers swooped in to attack, the researchers recorded how the flycatchers’ feathers moved and what sounds they made. The whole project took three years.</p> <p>"Recording a fast-flying fighting bird is really hard," Gómez-Bahamón said. "It took many attempts."</p> <p>The audio and video footage, as well as experiments with fork-tailed flycatcher plumes in a wind tunnel, revealed the birds create these trills with fluttering feathers. Airflow causes these plumes to vibrate with short repetitive whistles, much like the sounds <a href="">one can whistle using a blade of grass</a>.</p> <p>Gómez-Bahamón and her colleagues discovered the migratory subspecies made higher-pitched trills with their feathers than their nonmigratory cousins.</p> <p>The migrating males possess wing feathers with skinnier tips than those of their homebody brethren. These may have evolved to make it easier to fly longer distances. The researchers suggested a group of migratory fork-tailed flycatchers ceased to be migratory, and as their wing feathers thickened because they no longer made long journeys, they ended up sounding different from those of their migratory relatives.</p> <p>"This is super-challenging work -- these birds are really aerial, and they're not tame," said evolutionary ornithologist Richard Prum at Yale University, who did not take part in this research. "I was amazed at the detail of the analysis they were capable of doing."</p> <p>Aside from escapes and fights, males of both subspecies trill with their wings in the early morning when it is still dark, likely as displays to females, Gómez-Bahamón said. The birds sing songs, are quiet for a moment, and then perform a short flight where one can hear the fluttering.</p> <p>Since wing fluttering may help the birds communicate during mating season, Gómez-Bahamón and her colleagues suggest the feather “accents” they found may help further drive the subspecies apart. Eventually, the two types of flycatchers may evolve into fully separate species that cannot interbreed with one another. "Differences in migratory behavior can cascade to other behavioral traits," Gómez-Bahamón said.</p> <p>Future research will investigate whether related species display similar behavior. The scientists will also explore whether female fork-tailed flycatchers prefer sounds from males of their subspecies, Gómez-Bahamón said. Ornithologist Juan Ignacio Areta at the Institute of Bio and Geosciences of Northwest Argentina, who did not participate in this study, wonders how preventing the birds from making feather trills might influence mate choice. "Answering these exciting questions is difficult, and requires a lot of carefully designed field experiments," he said.</p> <p>The scientists detailed <a href="">their findings</a> Sept. 22 in the journal <em>Integrative and Comparative Biology</em>.</p> <p>Charles Q. Choi is a science reporter who has written for Scientific American, The New York Times, Wired, Science, Nature, and National Geographic News, among others. Reprinted with permission from <a href="">Inside Science</a>, an editorially independent news product of the American Institute of Physics, a nonprofit organization dedicated to advancing, promoting and serving the physical sciences.</p></div> <span><a title="View user profile." href="/author/sb-admin" lang="" about="/author/sb-admin" typeof="schema:Person" property="schema:name" datatype="">sb admin</a></span> <span>Thu, 09/24/2020 - 10:46</span> <div class="field field--name-field-blog-categories field--type-entity-reference field--label-inline"> <div class="field--label">Categories</div> <div class="field--items"> <div class="field--item"><a href="/channel/education" hreflang="en">Education</a></div> </div> </div> Thu, 24 Sep 2020 14:46:18 +0000 sb admin 151453 at Should A Doctor Prescribe A Walk In The Park? <span>Should A Doctor Prescribe A Walk In The Park?</span> <div class="field field--name-body field--type-text-with-summary field--label-hidden field--item"><p>Has your doctor recommended you go for regular jogs in the park, countryside walks, community food growing sessions, or some other nature-based activity? These so-called “green prescriptions” are typically given alongside conventional therapies and have existed in various forms for a number of years.</p> <p>In recognition of the potential health benefits of green prescriptions, the UK government has <a href="">just announced</a> a £4 million investment in a two-year pilot as part of its post-COVID-19 recovery plan, with plans to scale up in the future.</p> <p>There is increasing evidence of the benefits of contact with nature, and the World Health Organization has identified ten ways in which nature impacts positively on <a href="">our physical and mental health</a>. When parks and other greenspaces are accessible and inclusive they can promote physical activity, psychological relaxation and social cohesion.</p> <p>There is even evidence to suggest that contact with microbes in the environment can <a href="">“train” our immune systems</a> and reinforce the microbial communities on our skin, and in our airways and guts. These “microbiomes” could play a role in how our bodies respond to infectious diseases such as COVID-19 and to secondary infections. Microbes from the environment could also potentially supplement our bodies with <a href="">fatty acids such as butyrate</a>, which are linked to reduced inflammation and may promote mental health.</p> <p>Green prescriptions therefore have huge potential. But if they are to work, they need to be seen as the start of a much more holistic mode of health and social care delivery: part of a post-COVID “new normal”. This would chime strongly both with the renewed appreciation of nature and the surge in community mobilization and action we saw under the lockdown.</p> <p>This needs to go beyond simply substituting green for conventional prescriptions. Instead we should provide greener, more natural settings and practices for health, social care, education, transport and active travel. A good example is the GoGoGreen project at a primary school we have worked with in Sheffield. There, greening a school playground not only created a barrier against air pollution from vehicle emissions but also provided multiple other benefits to the school community and started a conversation about cleaner modes of travel.</p> <p>Green prescribing cannot be seen as a low-cost alternative to conventional treatments. To be effective it still demands investment and resources. The two year pilot is welcome, but if it is to be successful in the long-run the government must make a firm commitment to scaling-up while also addressing systemic issues such as social inequality. All this will take time, and if this holistic approach is not adopted then people in crisis with more immediate priorities will be less likely to go on that prescribed walk in the woods.</p> <p>Our own research on <a href="">improving wellbeing through urban nature</a> in Sheffield confirms that people in more deprived communities, with <a href="">poorer health and shorter life expectancies</a>, don’t have the same levels of access to high quality, <a href="">well-maintained greenspaces</a>. These are the people that arguably most need green prescriptions, but if they don’t have the basic access then those prescriptions are unlikely to be effective. What’s more, many <a href="">doctors are not aware of green prescribing</a>, nor do they have a firm understanding of the benefits or know how to get involved.</p> <p>Our research also reveals that context is critical and green prescriptions need to be <a href="">rooted in their</a> local area and closely related to the people and places who are going to use them. A wealthy white pensioner in a rural area is likely to have very different experience of and access to nature compared with a young working class person of color in an inner city. A formulaic top-down approach is unlikely to work for both these people.</p> <h2>Recommendations</h2> <p>To sum up, this is what we need to make green prescriptions a success.</p> <p>They have to be part of a systemic approach to incorporating nature-based interventions and <a href="">nature-based thinking</a> in urban infrastructure and service provision.</p> <p>The prescribing process needs to be made easy, for doctors, social care professionals and patients. GPs often lack time and resources, while patients may lack motivation and confidence, or have little previous positive experiences of nature.</p> <p>Green prescribing also needs to be seen as one part of a holistic health-promotion strategy based on a planetary health perspective. In order to care for ourselves, we also need to care for our environments.</p> <p>Finally, we need new ways of working with local organisations and communities to understand what’s needed in local contexts, and to build skills and capacity.</p> <p><span>By <a href="">Anna Jorgensen</a>, Chair in Urban Natural Environments, Health and Wellbeing, University of Sheffield and <a href="">Jake M. Robinson</a>, PhD Researcher, Department of Landscape, University of Sheffield. Jorgensen receives funding from the British Academy and the European Commission. Robinson receives funding from the Economic and Social Research Council (ESRC). He is affiliated with inVIVO Planetary Health, the Healthy Urban Microbiome Initiative and Greener Practice. This article is republished from The Conversation under a Creative Commons license. Read the <a href="">original article</a>. <img alt="The Conversation" height="1" src="" width="1" /></span></p></div> <span><a title="View user profile." href="/author/sb-admin" lang="" about="/author/sb-admin" typeof="schema:Person" property="schema:name" datatype="">sb admin</a></span> <span>Fri, 07/24/2020 - 15:39</span> <div class="field field--name-field-blog-categories field--type-entity-reference field--label-inline"> <div class="field--label">Categories</div> <div class="field--items"> <div class="field--item"><a href="/channel/medicine" hreflang="en">Medicine</a></div> </div> </div> Fri, 24 Jul 2020 19:39:42 +0000 sb admin 151452 at Opportunity Costs And Why Fireworks Complaints Are Up This Year <span>Opportunity Costs And Why Fireworks Complaints Are Up This Year</span> <div class="field field--name-body field--type-text-with-summary field--label-hidden field--item"><p>The number of fireworks being lit off at night is <a href="">out of control this year</a>.</p> <p>While people often light off fireworks close to the Fourth of July, this year fireworks have been lit in large numbers starting weeks earlier. <a href="">New York City had a 4,000% increase</a> in fireworks complaints in the first two weeks of June compared with last year. This prompted <a href="">Mayor Bill de Blasio to vow a crackdown</a> on illegal fireworks.</p> <p>Complaints about fireworks are not confined to just New York City, but in cities across the country like <a href="">San Francisco</a>, <a href="">Denver</a>, <a href="">Harrisburg</a>, <a href="">Albuquerque</a>, <a href="">Providence</a> and many <a href="">other places</a>. This has led to a <a href="">rise in conspiracy theories</a>, including one that the nightly noise is an <a href="">elaborate government plot to create confusion</a> in neighborhoods.</p> <p>I <a href="">am an economist</a> who has <a href="">spoken</a> and <a href="">written</a> <a href="">about</a> <a href="">fireworks</a> for years. After hearing a constant barrage nightly for weeks, I began wondering why so many people are lighting off fireworks this year.</p> <h2>It isn’t economics</h2> <p>There are two possible economic reasons behind an increase in fireworks usage: falling prices or increased supply. However, neither of these is the culprit behind the increase in fireworks usage this year.</p> <p>The vast majority of the fireworks individuals shoot off in the U.S. are manufactured <a href="">overseas, mainly in China</a>. Each <a href="">shipment of fireworks brought into the U.S.</a> includes a detailed invoice that shows the quantity and price the importer paid.</p> <p><a href="">Price data</a> for the first four months of 2020 show importers paid an average of US$2.63 per kilogram for fireworks from China. A year earlier, importers paid an average of $2.60 per kilogram. This means prices rose slightly from 2019 to 2020, eliminating the falling price argument.</p> <p>Increased supply is also not the reason. In a typical year there are two holidays with widespread firework usage; New Year’s Eve and the Fourth of July.</p> <p>Deliveries in 2020 are an exception to this pattern. Because of the coronavirus, the U.S. imported very few fireworks in March. During the first four months of 2020 the U.S. imported 9 million kilograms of fireworks from China. While this seems like a large number, it is <a href="">one-third less than a year earlier</a>.</p> <p><img alt="Fireworks in Manhattan New Years Eve" data-entity-type="file" data-entity-uuid="da8c9d4e-8dcd-4d87-918e-9b96264c0b5e" src="/files/inline-images/fireworks%20new%20years.jpg" /></p> <p><em><span>Fireworks are much more common around holidays like New Year’s Eve.</span> <span><a href="">Tayfun Coskun/Anadolu Agency via Getty Images</a></span></em></p> <h2>Nor is it legal reform</h2> <p>Another potential reason could be changes in laws.</p> <p>Most major dense cities like <a href="">New York</a>, <a href="">Chicago</a> and <a href="">San Francisco ban</a> fireworks.</p> <p>However, if neighboring jurisdictions have loosened their rules, then people can easily drive outside the city to purchase fireworks.</p> <p>There has been a steady reduction in <a href=",%25201976-2018.pdf">state prohibitions against</a> individuals using fireworks. <a href="">Today only one state, Massachusetts</a>, completely prohibits individuals from owning and using any type of fireworks. <a href="">All the rest allow</a> them in some form.</p> <p>However, the most recent two states to allow consumers to shoot off fireworks are <a href="">New Jersey</a> in 2017 and <a href="">Delaware</a> in 2018. Since most states relaxed prohibitions against fireworks more than two years ago, recent rule changes also cannot be behind the increase.</p> <h2>The most likely culprit</h2> <p>To find the real reason, it helps to consider that millions of Americans have been locked down in their homes and apartments for months. As an employee at a fireworks store in Stroudsburg, Pennsylvania, <a href="">put it</a>, “People are bored. They just want to blow stuff up.”</p> <p>While this argument is understandable, I think the most likely reason is even simpler. And it has a lot to do with <a href="">opportunity costs</a>, something economists spend a lot of time thinking about.</p> <p>Opportunity costs put a dollar value on what else a person could do with their time. For example, before the pandemic, I had many choices at night. I could work, go out with friends, watch television or see a movie in the theater.</p> <p>By shutting down restaurants, theaters, bars and other venues, COVID-19 has dramatically reduced my choices.</p> <p>The pandemic has also <a href="">thrown millions out of work</a>. Many people who would normally be working at night are not. This means the opportunity cost for using fireworks is exceptionally low compared with before, since there are so few opportunities to socialize, be entertained or work.</p> <p>Beyond lower opportunity costs for fireworks users, there are many unemployed people who are now looking for opportunities to earn money. Buying fireworks in a rural area like northern Pennsylvania and selling them at higher prices in a city that bans their sale, such as New York City, can be <a href="">easy and profitable</a>.</p> <p>So few arrests are made for fireworks that the FBI, which tracks problems like moonshining and polygamy on its <a href="">detailed list of offenses</a>, does not give it a category.</p> <h2>Idle hands</h2> <p>Fireworks are dangerous. While <a href="">few people die each year</a> from using them, the <a href="">latest figures for 2019</a> show that fireworks hurt about 10,000 people per year in the U.S.</p> <p>However, massive <a href="">unemployment caused by COVID-19 is also dangerous</a>.</p> <p>There is an old quote that idle hands lead to mischief. In this case, idle people lead to large amounts of illegal firework usage.</p> <p>My belief is that once the millions of unemployed people in the U.S. go back to work, the number of illegal fireworks shot off will rapidly decrease and will once again be limited to the times around New Year’s Eve and the Fourth of July.</p> <p><em>Top image: Fireworks light up the sky over New York City in 2019. <a href="">Gary Hershorn/Getty Images</a></em></p> <p><span>By <a href="">Jay L. Zagorsky</a>, Senior Lecturer, Questrom School of Business, <a href="">Boston University</a>. This article is republished from <a href="">The Conversation</a> under a Creative Commons license. Read the <a href="">original article</a>.<img alt="The Conversation" height="1" src="" width="1" /></span></p></div> <span><a title="View user profile." href="/author/sb-admin" lang="" about="/author/sb-admin" typeof="schema:Person" property="schema:name" datatype="">sb admin</a></span> <span>Tue, 06/30/2020 - 12:17</span> <div class="field field--name-field-blog-categories field--type-entity-reference field--label-inline"> <div class="field--label">Categories</div> <div class="field--items"> <div class="field--item"><a href="/channel/brain-and-behavior" hreflang="en">Brain and Behavior</a></div> </div> </div> Tue, 30 Jun 2020 16:17:46 +0000 sb admin 151451 at NVX-CoV2373: Here's How The Coronavirus Vaccine Based On A Flu Shot Works <span>NVX-CoV2373: Here&#039;s How The Coronavirus Vaccine Based On A Flu Shot Works</span> <div class="field field--name-body field--type-text-with-summary field--label-hidden field--item"><p>A new trial has begun in Victoria <a href="">this week</a> to evaluate a potential vaccine against COVID-19.</p> <p>The vaccine is called NVX-CoV2373 and is from a US biotech company, Novavax.</p> <p>The trial will be carried out across Melbourne and Brisbane, and is the first human trial of a vaccine specifically for COVID-19 to take place in Australia.</p> <p>This vaccine is actually based on a vaccine that was already in development for influenza. But how might it work against SARS-CoV-2, the coronavirus that causes COVID-19?</p> <h2>What’s in the mix?</h2> <p>Vaccines trigger an immune response by introducing the cells of our immune system to a virus in a safe way, without any exposure to the pathogen itself.</p> <p>All vaccines have to do two things. The first is make our immune cells bind to and “eat up” the vaccine. The second is to activate these immune cells so they’re prepared to fight the current and any subsequent threats from the virus in question.</p> <p>We often add molecules called adjuvants to vaccines to deliver a danger signal to the immune system, activate immune cells and trigger a strong immune response.</p> <p>The Novavax vaccine is what we call a “subunit” vaccine because, instead of delivering the whole virus, it delivers only part of it. The element of SARS-CoV-2 in this vaccine is the spike protein, which is found on the surface of the virus.</p> <p>By targeting a particular protein, a subunit vaccine is a great way to focus the immune response.</p> <p>However, protein by itself is not very good at binding to and activating the cells of our immune system. Proteins are generally soluble, which doesn’t appeal to immune cells. They like something <a href="">they can chew on</a>.</p> <p>So instead of soluble protein, Novavax has assembled the SARS-CoV-2 spike protein into very small particles, called nanoparticles. To immune cells, these nanoparticles look like little viruses, so immune cells can bind to these pre-packaged chunks of protein, rapidly engulfing them and becoming activated.</p> <p>The Novavax vaccine also contains an <a href="">adjuvant called Matrix-M</a>. While the nanoparticles deliver a modest danger signal, Matrix-M can be added to deliver a much stronger danger signal and really wake up the immune system.</p> <p><img alt="The spike protein is formed into nanoparticles to attract immune cells, and Matrix-M is added as an adjuvant to further activate immune cells." data-entity-type="file" data-entity-uuid="c42655cf-72d9-44e4-a4b0-2408e941ada9" src="/files/inline-images/coronavirus%20protein%20spike_0.jpg" /></p> <p><span>The spike protein is formed into nanoparticles to attract immune cells, and Matrix-M is added as an adjuvant to further activate immune cells.</span> <span><span>Author provided</span></span></p> <h2>Rethinking an influenza vaccine</h2> <p>The Novavax vaccine for SARS-CoV-2 is based on a vaccine the company was already developing for influenza, called NanoFlu.</p> <p>The NanoFlu vaccine contains similar parts – nanoparticles with the Matrix-M adjuvant. But it uses a different protein in the nanoparticle (hemagglutinin, which is on the outside of the influenza virus).</p> <p>In October last year, Novavax started testing NanoFlu in a <a href="">phase III clinical trial</a>, the last level of clinical testing before a vaccine can be licensed. This trial had 2,650 volunteers and researchers were comparing whether NanoFlu performed as well as Fluzone, a standard influenza vaccine.</p> <p>An important feature of this trial is participants were over the age of 65. Older people tend to have <a href="">poorer responses</a> to vaccines, because immune cells become more difficult to activate as we age.</p> <p>This trial is ongoing, with volunteers to be followed until the end of the year. However, <a href="">early results</a> suggest NanoFlu can generate significantly higher levels of antibodies than Fluzone – even given the older people in the trial.</p> <p>Antibodies are small proteins made by our immune cells which bind strongly to viruses and can stop them from infecting cells in the nose and lungs. So increased antibodies with NanoFlu should result in lower rates of infection with influenza.</p> <p>These results were similar to those released after the <a href="">phase I trial</a> of NanoFlu, and suggest NanoFlu would be the superior vaccine for influenza.</p> <p>So the big question is – will the same strategy work for SARS-CoV-2?</p> <p><img alt="The Novavax vaccine is one of several potential COVID-19 vaccines being trialled around the world." data-entity-type="file" data-entity-uuid="65bfbd37-4f72-4ee2-bef0-d5d70dd1e74c" height="263" src="/files/inline-images/coronavirus%20vaccines%20worldwide.jpg" width="394" /></p> <p><em><span>The Novavax vaccine is one of several potential COVID-19 vaccines being trialed around the world.</span> <span><span>Shutterstock</span></span></em></p> <h2>The Australian clinical trial</h2> <p>The <a href=";recrs=ab&amp;draw=2&amp;rank=1&amp;view=record">new phase I/II trial</a> will enrol around 131 healthy volunteers aged between 18 and 59 to assess the vaccine’s safety and measure how it affects the body’s immune response.</p> <p>Some volunteers will not receive the vaccine, as a placebo control. The rest will receive the vaccine, in a few different forms.</p> <p>The trial will test two doses of protein nanoparticles – a low (5 microgram) or a high (25 microgram) dose. Both doses will be delivered with Matrix-M adjuvant but the higher dose will also be tested without Matrix-M.</p> <p>All groups will receive two shots of the vaccine 21 days apart, except one group that will just get one shot.</p> <p>This design enables researchers to ask four important questions:</p> <ol><li> <p>can the vaccine induce an immune response?</p> </li> <li> <p>if so, what dose of nanoparticle is best?</p> </li> <li> <p>do you need adjuvant or are nanoparticles enough?</p> </li> <li> <p>do you need two shots or is one enough?</p> </li> </ol><p>While it’s not yet clear how the vaccine will perform for SARS-CoV-2, Novavax has <a href="">reported</a> it generated strong immune responses in animals.</p> <p>And we know NanoFlu performed well and had a good safety profile for influenza. NanoFlu also seemed to work well in older adults, which would be essential for a vaccine for COVID-19.</p> <p>We eagerly await the first set of results, expected in a <a href="">couple of months</a> – an impressive turnaround time for a clinical trial. If this initial study is successful, the phase II portion of the trial will begin, with more participants.</p> <p>The Novavax vaccine joins <a href="">at least nine other vaccine candidates</a> for SARS-CoV-2 currently in clinical testing around the world.</p> <p><span>By <a href="">Kylie Quinn</a>, Vice-Chancellor's Research Fellow, School of Health and Biomedical Sciences, RMIT University and <a href="">Kirsty Wilson</a>, Postdoctoral Research Fellow, RMIT University. This article is republished from The Conversation under a Creative Commons license. Read the <a href="">original article</a>.<img alt="The Conversation" height="1" src="" width="1" /></span></p></div> <span><a title="View user profile." href="/author/sb-admin" lang="" about="/author/sb-admin" typeof="schema:Person" property="schema:name" datatype="">sb admin</a></span> <span>Wed, 05/27/2020 - 10:18</span> <div class="field field--name-field-blog-categories field--type-entity-reference field--label-inline"> <div class="field--label">Categories</div> <div class="field--items"> <div class="field--item"><a href="/channel/medicine" hreflang="en">Medicine</a></div> </div> </div> Wed, 27 May 2020 14:18:04 +0000 sb admin 151450 at The 'Uplift of the Tibetan Plateau' Myth <span>The &#039;Uplift of the Tibetan Plateau&#039; Myth</span> <div class="field field--name-body field--type-text-with-summary field--label-hidden field--item"><p>'The uplift of the Tibetan Plateau' is invoked to explain various phenomena, from monsoon dynamics to biodiversity evolution and everything in between. It's not accurate, finds<a href=""> a new paper</a>.</p> <p>The orogeny of the Tibetan region (Tibet, The Himalaya and the Hengduan Mountains) dates back approximately 200 million years, long before the arrival of India, and was the product of earlier Gondwanan tectonic block collisions that produced a complex of mountain chains and valleys. The review finds that the concept of an extensive low-relief Tibet, rising in its entirety as a result of the India-Eurasia collision, is false, and the product of overly simplistic modeling.</p> <p>Previous stable isotope and fossil-based estimates of past surface heights were often contradictory; isotopes tend to record the height of mountain crests, while the fossils are more indicative of where sediments accumulate in valley bottoms. The isotopic bias towards uplands means that even valleys appear as uplands at the height of the bounding mountains and so appear as an elevated plateau, a result confirmed by isotope-enabled climate modelling. By combining well-dated multiple paleoaltimetric methods a better understanding of past topography emerges.</p> <p>The formation of a complex topography, and in places thickened crust, before the arrival of India suggests that the formation of the Tibetan Plateau was not only due to the India-Eurasia collision and this has important implications for the amount of crustal shortening and the size of 'greater India' before collision.</p> <p><img src="" width="700" /><br /><em>Tibet was assembled by a succession of Gondwanan tectonic blocks (terranes) colliding with Eurasia over a period of about 200 million years.</em></p> <p>Previous work pointed to a rise of eastern Tibet and the Hengduan Mountains in the Miocene, but recent radiometric re-dating of key sites shows the region was elevated before plateau formation and the rise of the Himalaya. Uplift began in the Eocene in large part due to extrusion of parts of Tibet beginning as early as ~ 52 million years ago and extended into the early Oligocene, with landscape dissection through the expansion of river drainages taking place in the Miocene (subject to the dating being correct) as the monsoons strengthened.</p> <p>The Himalaya began to rise in the Eocene, but only crested the pre-existing Gangdese mountains that already formed a 4-5 km high 'wall' along southern Tibet after the mid Miocene. North of the Gangdese, along the Bangong-Nujiang Suture south of the Tangula mountains, a deep ancient east-west aligned great central valley existed until early in the Neogene (approximately 23 million years ago) and later in its history was internally-drained. Numerous fossil finds show lakeside sub-tropical vegetation in this valley remained below 2.3 km above sea level for much of its history, the valley floor only rising in the Neogene to form today's flat plateau through ongoing tectonic compression from India and sediment infilling.</p> <p>'Uplift' in geology relates to the rise of rocks and work done against gravity, so the infilling of basins by sediment to contribute to the formation of a low-relief surface means that Tibet was never 'uplifted' as a plateau, nor was that rise solely a consequence of the India-Eurasia collision.</p></div> <span><a title="View user profile." href="/author/sb-admin" lang="" about="/author/sb-admin" typeof="schema:Person" property="schema:name" datatype="">sb admin</a></span> <span>Tue, 05/12/2020 - 10:40</span> <div class="field field--name-field-blog-categories field--type-entity-reference field--label-inline"> <div class="field--label">Categories</div> <div class="field--items"> <div class="field--item"><a href="/channel/environment" hreflang="en">Environment</a></div> </div> </div> Tue, 12 May 2020 14:40:03 +0000 sb admin 151449 at The Yeast All Around Us <span>The Yeast All Around Us</span> <div class="field field--name-body field--type-text-with-summary field--label-hidden field--item"><p>With people confined to their homes, there is more interest in home-baked bread than ever before. And that means a lot of people are making friends with yeast for the first time. I am a <a href="">professor of hospitality management and a former chef, and I teach in my university’s fermentation science program</a>.</p> <p>As friends and colleagues struggle for success in using yeast in their baking – and occasionally brewing – I’m getting bombarded with questions about this interesting little microorganism.</p> <h2>A little cell with a lot of power</h2> <p>Yeasts are single-celled organisms in the fungus family. There are <a href="">more than 1,500 species of them on Earth</a>. While each individual yeast is only one cell, they are surprisingly complex and contain a nucleus, DNA and many other cellular parts found in more complicated organisms.</p> <p>Yeasts break down complex molecules into simpler molecules to produce the energy they live on. They can be found on most plants, floating around in the air and in soils across the globe. There are 250 or so of these yeast species that can <a href="">convert sugar into carbon dioxide and alcohol</a> – valuable skills that humans have used for millennia. Twenty-four of these make foods that actually taste good.</p> <p>Among these 24 species is one called <em>Saccharomyces cerevisiae</em>, which means “sugar-eating fungus.” This is bread yeast, the yeast we humans know and love most dearly for the food and drinks it helps us make.</p> <p><img alt="&lt;p&gt;An invisible organism with worldwide influence. &lt;span&gt;&lt;a href=&quot;;&gt; KATERYNA KON/SCIENCE PHOTO LIBRARY via Getty Images via The Conversation&lt;/a&gt;&lt;/span&gt;&lt;/p&gt;" data-entity-type="file" data-entity-uuid="a0737260-12f7-4f4b-9f1f-9ffca3bd3375" src="/files/inline-images/yeast%20cell.jpg" width="700" /></p> <p><em>An invisible organism with worldwide influence. <span><a href=""> KATERYNA KON/SCIENCE PHOTO LIBRARY via Getty Images via The Conversation</a></span></em></p> <p>The process starts out the same whether you are making bread or beer. Enzymes in the yeast convert sugar into alcohol and carbon dioxide. With bread, a baker wants to <a href="">capture the carbon dioxide to leaven the bread</a> and make it rise. With beer, a brewer wants to capture the alcohol.</p> <p>Bread has been “the staff of life” for <a href="">thousands of years</a>. The first loaf of bread was probably a <a href="">happy accident</a> that occurred when some yeast living on grains began to ferment while some dough for flatbreads – think matzo or crackers – was being made. The first purposely made leavened bread was likely made by <a href="">Egyptians about 3,000 years ago</a>. Leavened bread is now a staple in almost every culture on Earth. Bread is inexpensive, nutritious, delicious, portable and easy to share. Anywhere wheat, rye or barley could be grown in sufficient quantities, bread became the basic food in most people’s diet.</p> <p> </p> <p><a href=";q=45&amp;auto=format&amp;w=1000&amp;fit=clip"><img alt="" src=";q=45&amp;auto=format&amp;w=754&amp;fit=clip" /></a></p> <p><em><span>Yeast makes bread fluffy and flavorful.</span> <span><a href=";uiloc=thumbnail_same_series_adp">Poh Kim Yeoh/EyeEm via Getty Images via The Conversation</a></span></em></p> <h2> </h2> <h2>No yeast, no bread</h2> <p> </p> <p>When you mix yeast with a bit of water and flour, the yeast begins to eat the long chains of carbohydrates found in the flour called starches. This does two important things for baking: It changes the chemical structure of the carbohydrates, and it makes bread rise.</p> <p>When yeast breaks down starch, it produces carbon dioxide gas and ethyl alcohol. This CO2 is trapped in the dough by stringy protein strands called gluten and causes the dough to rise. After baking, those little air pockets are locked into place and result in airy, fluffy bread.</p> <p>But soft bread is not the only result. When yeast break down the starches in flour, it turns them into flavorful sugars. The longer you let the dough rise, the <a href="">stronger these good flavors will be</a>, and some of the <a href="">most popular bread recipes</a> use this to their advantage.</p> <p> </p> <h2>The supermarket’s out of yeast; now what?</h2> <p> </p> <p>Baking bread at home is fun and easy, but what if your store doesn’t have any yeast? Then it’s sourdough to the rescue!</p> <p>Yeast is everywhere, and it’s really easy to collect yeast at home that you can use for baking. These wild yeast collections tend to gather yeasts as well as bacteria – usually <em>Lactobacillus brevis</em> that is used in cheese and yogurt production – that add the complex sour flavors of sourdough. Sourdough starters have been made from fruits, vegetables or even dead wasps. Pliny the Elder, the Roman naturalist and philosopher, was the first to suggest the dead wasp recipe, and it works because <a href="">wasps get coated in yeasts</a> as they eat fruit. But please don’t do this at home! You don’t need a wasp or a murder hornet to make bread. All you really need to make sourdough starter is wheat or rye flour and water; the yeast and bacteria floating around your home will do the rest.</p> <p>To make your own sourdough starter, mix a half-cup of distilled water with a half-cup of whole wheat flour or rye flour. Cover the top of your jar or bowl loosely with a cloth, and let it sit somewhere warm for 24 hours. After 24 hours, stir in another quarter-cup of distilled water and a half-cup of all-purpose flour. Let it sit another 24 hours. Throw out about half of your doughy mass and stir in another quarter-cup of water and another half-cup of all-purpose flour.</p> <p>Keep doing this every day until your mixture begins to bubble and smells like rising bread dough. Once you have your starter going, you can use it to make bread, pancakes, <a href="">even pizza crust</a>, and you will never have to buy yeast again.</p> <p> </p> <p><a href="/files/inline-images/yeast%20lab.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=1000&amp;fit=clip"><img alt="Lab yeast" data-entity-type="file" data-entity-uuid="069b4dc6-b893-4afc-afed-fdb0428810a8" src="/files/inline-images/yeast%20lab.jpg" /></a></p> <p><em><span>Yeast is used in laboratories and factories as well as kitchens.</span> <span><a href="">borzywoj/iStock/Getty Images Plus via Getty Images via The Conversation</a></span></em></p> <h2> </h2> <h2>More than just bread and booze</h2> <p> </p> <p>Because of their similarity to complicated organisms, large size and ease of use, yeasts have been central to scientific progress for hundreds of years. Study of yeasts played a huge role in <a href="">kick-starting the field of microbiology</a> in the early 1800s. More than 150 years later, one species of yeast was the first organism with a nucleus to have <a href="">its entire genome sequenced</a>. Today, scientists use yeast in <a href="">drug discovery</a> and as tools to study <a href="">cell growth in mammals</a> and are exploring ways to use yeast to make biofuel <a href="">from waste products like cornstalks</a>.</p> <p>Yeast is a remarkable little creature. It has provided delicious food and beverages for millennia, and to this day is a huge part of human life around the world. So the next time you have a glass of beer, toast our little friends that make these foods part of our enjoyment of life.</p> <p><span>By <a href="">Jeffrey Miller</a>, Associate Professor, Hospitality Management, Colorado State University. This article is republished from The Conversation under a Creative Commons license. Read the <a href="">original article</a>.</span></p> <p><img alt="The Conversation" height="1" src="" width="1" /></p></div> <span><a title="View user profile." href="/author/sb-admin" lang="" about="/author/sb-admin" typeof="schema:Person" property="schema:name" datatype="">sb admin</a></span> <span>Mon, 05/11/2020 - 11:54</span> <div class="field field--name-field-blog-categories field--type-entity-reference field--label-inline"> <div class="field--label">Categories</div> <div class="field--items"> <div class="field--item"><a href="/channel/life-sciences" hreflang="en">Life Sciences</a></div> </div> </div> Mon, 11 May 2020 15:54:57 +0000 sb admin 151448 at The Biology Of Why Coronavirus Is So Deadly <span>The Biology Of Why Coronavirus Is So Deadly</span> <div class="field field--name-body field--type-text-with-summary field--label-hidden field--item"><p>COVID-19 is caused by a coronavirus called SARS-CoV-2. Coronaviruses belong to a group of viruses that infect animals, from peacocks to whales. They’re named for the bulb-tipped spikes that project from the virus’s surface and give the appearance of a corona surrounding it.</p> <p>A coronavirus infection usually plays out one of two ways: as an infection in the lungs that includes some cases of what people would call the common cold, or as an infection in the gut that causes diarrhea. COVID-19 starts out in the lungs like the common cold coronaviruses, but then causes havoc with the immune system that can lead to long-term lung damage or death.</p> <p>SARS-CoV-2 is genetically very similar to other human respiratory coronaviruses, including SARS-CoV and MERS-CoV. However, the subtle genetic differences translate to significant differences in how readily a coronavirus infects people and how it makes them sick.</p> <p> </p> <figure role="group"><img alt="coronavirus dying cell" data-entity-type="file" data-entity-uuid="f3b7eb12-81ba-4ff9-b519-463a5715ac0a" src="/files/inline-images/coronavirus%20biology.jpg" width="700" /><figcaption><em>SARS-CoV-2 virus particles (pink dots) on a dying cell. <a href="">National Institute of Allergy and Infectious Diseases, NIH</a></em></figcaption></figure><p> </p> <p>SARS-CoV-2 has all the <a href=";VirusLineage_ss=SARS-CoV-2,%20taxid:2697049">same genetic equipment</a> as <a href=";VirusLineage_ss=Severe%20acute%20respiratory%20syndrome-related%20coronavirus,%20taxid:694009&amp;CollectionDate_dr=2002-01-01T06:00:00.000Z%20TO%202019-03-28T05:00:00.000Z">the original SARS-CoV</a>, which caused a global outbreak in 2003, but with around 6,000 mutations sprinkled around in the usual places where coronaviruses change. Think whole milk versus skim milk.</p> <p>Compared to other human coronaviruses like <a href=";VirusLineage_ss=Middle%20East%20respiratory%20syndrome-related%20coronavirus%20(MERS-CoV),%20taxid:1335626&amp;CollectionDate_dr=2002-01-01T06:00:00.000Z%20TO%202019-03-28T05:00:00.000Z">MERS-CoV</a>, which emerged in the Middle East in 2012, the new virus has customized versions of the same general equipment for invading cells and copying itself. However, SARS-CoV-2 has a totally different set of genes called accessories, which give this new virus a little advantage in specific situations. For example, MERS has a particular protein that shuts down a cell’s ability to sound the alarm about a viral intruder. SARS-CoV-2 has an unrelated gene with an as-yet unknown function in that position in its genome. Think cow milk versus almond milk.</p> <p> </p> <h2>How the virus infects</h2> <p> </p> <p>Every coronavirus infection starts with a virus particle, <a href="">a spherical shell that protects a single long string of genetic material</a> and inserts it into a human cell. The genetic material instructs the cell to make around 30 different parts of the virus, allowing the virus to reproduce. The <a href="">cells that SARS-CoV-2 prefers to infect</a> have a protein called ACE2 on the outside that is important for regulating blood pressure.</p> <p>The infection begins when the long spike proteins that protrude from the virus particle <a href="">latch on to the cell’s ACE2 protein</a>. From that point, the spike transforms, unfolding and refolding itself using coiled spring-like parts that start out buried at the core of the spike. The reconfigured spike hooks into the cell and crashes the virus particle and cell together. This forms a channel where the string of viral genetic material can snake its way into the unsuspecting cell.</p> <p><img alt="" src="" width="700" /></p> <p><em><span>An illustration of the SARS-CoV-2 spike protein shown from the side (left) and top. The protein latches onto human lung cells.</span> </em><span><a href=""><em>5-HT2AR/Wikimed</em>ia</a></span></p> <p>SARS-CoV-2 spreads from person to person by close contact. The <a href="">Shincheonji Church outbreak in South Korea</a> in February provides a good demonstration of how and how quickly SARS-CoV-2 spreads. It seems one or two people with the virus sat face to face very close to uninfected people for several minutes at a time in a crowded room. Within two weeks, several thousand people in the country were infected, and more than half of the infections at that point were attributable to the church. The outbreak got to a fast start because public health authorities were unaware of the potential outbreak and were not testing widely at that stage. Since then, authorities have worked hard and the number of <a href="">new cases in South Korea has been falling steadily</a>.</p> <p> </p> <h2>How the virus makes people sick</h2> <p> </p> <p>SARS-CoV-2 grows in type II lung cells, which secrete a soap-like substance that helps air slip deep into the lungs, and in cells lining the throat. As with SARS, most of the damage in COVID-19, the illness caused by the new coronavirus, is caused by the immune system carrying out a scorched earth defense to stop the virus from spreading. Millions of cells from the immune system invade the infected lung tissue and <a href="">cause massive amounts of damage</a> in the process of cleaning out the virus and any infected cells.</p> <p>Each COVID-19 lesion ranges from the size of a grape to the size of a grapefruit. The challenge for health care workers treating patients is to support the body and keep the blood oxygenated while the lung is repairing itself.</p> <p><iframe allowfullscreen="" frameborder="0" height="260" src=";start=0" width="440"></iframe></p> <p> </p> <p><strong><span>How SARS-CoV-2 infects, sickens and kills people</span></strong></p> <p> </p> <p>SARS-CoV-2 has a sliding scale of severity. Patients under age 10 seem to clear the virus easily, most people under 40 seem to bounce back quickly, but <a href="">older people suffer from increasingly severe COVID-19</a>. The ACE2 protein that SARS-CoV-2 uses as a door to enter cells is also important for regulating blood pressure, and it does not do its job when the virus gets there first. This is one reason COVID-19 is more severe in people with high blood pressure.</p> <p>SARS-CoV-2 is <a href="">more severe than seasonal influenza</a> in part because it has many more ways to stop cells from calling out to the immune system for help. For example, one way that cells try to respond to infection is by making interferon, the alarm signaling protein. SARS-CoV-2 blocks this by a combination of camouflage, snipping off protein markers from the cell that serve as distress beacons and finally shredding any anti-viral instructions that the cell makes before they can be used. As a result, COVID-19 can fester for a month, causing a little damage each day, while most people get over a case of the flu in less than a week.</p> <p>At present, the transmission rate of SARS-CoV-2 is <a href="">a little higher than that of the pandemic 2009 H1N1</a> influenza virus, but SARS-CoV-2 is <a href="">at least 10 times as deadly</a>. From the data that is available now, COVID-19 seems a lot like severe acute respiratory syndrome (SARS), though it’s less likely than SARS to be severe.</p> <p> </p> <h2>What isn’t known</h2> <p> </p> <p>There are still many mysteries about this virus and coronaviruses in general – the nuances of how they cause disease, the way they interact with proteins inside the cell, the structure of the proteins that form new viruses and how some of the basic virus-copying machinery works.</p> <p>Another unknown is how COVID-19 will respond to changes in the seasons. The <a href="">flu tends to follow cold weather</a>, both in the northern and southern hemispheres. Some other human coronaviruses spread at a low level year-round, but then <a href="">seem to peak in the spring</a>. But <a href="">nobody really knows for sure</a> why these viruses vary with the seasons.</p> <p>What is amazing so far in this outbreak is all the good science that has come out so quickly. The research community learned about <a href="">structures of the virus spike protein and the ACE2 protein</a> with part of the spike protein attached just a little over a month after the genetic sequence became available. I spent my first 20 or so years working on coronaviruses without the benefit of either. This bodes well for better understanding, preventing and treating COVID-19.</p> <p><span>By <a href="">Benjamin Neuman</a>, Professor of Biology, <em><a href="">Texas A&amp;M University-Texarkana</a>. This article is republished from <a href="">The Conversation</a> under a Creative Commons license. Read the <a href="">original article</a>.</em></span></p> <p><em><img alt="The Conversation" height="1" src="" width="1" /></em></p></div> <span><a title="View user profile." href="/author/conversation" lang="" about="/author/conversation" typeof="schema:Person" property="schema:name" datatype="">The Conversation</a></span> <span>Thu, 04/02/2020 - 14:02</span> <div class="field field--name-field-blog-categories field--type-entity-reference field--label-inline"> <div class="field--label">Categories</div> <div class="field--items"> <div class="field--item"><a href="/channel/life-sciences" hreflang="en">Life Sciences</a></div> </div> </div> Thu, 02 Apr 2020 18:02:27 +0000 The Conversation 151447 at