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As social animals, humans tend to form groups that can range in size from a few individual members to entire nation-states. Historically and through the present day, human groups frequently come into conflict. A noted feature of human intergroup…

Wind-pollinated plants—including trees, grasses, and weeds—produce most of the pollen that affects seasonal allergy sufferers. Wind-pollinated plants produce great amounts of pollen grains that are very small in size. For example, one ragweed plant…

Neuroscientists have long sought to explain how the brain correctly recognizes a stimulus despite the stimulus appearing under different circumstances with widely variable external factors. For example, with regard to olfactory stimuli, humans can…

A newly identified coronavirus, provisionally termed 2019-nCoV (an acronym for 2019 novel coronavirus) and subsequently named "severe acute respiratory syndrome coronavirus 2" (SARS-CoV-2), emerged in central China in November 2019. The disease…

Renowned as adept fliers and as some of the first insects to have ever developed wings, with a fossil record going back more than 300 million years, dragonflies (class Odonata) have long interested scientists across interdisciplinary lines. A recent…

Researchers are learning more about how plants respond to "alarm signals" released by other plants that are under attack by herbivores. To warn conspecifics about predators, many animals issue alarms by vocalizing or emitting odors. In the case of…

Studies have shown that all classes of vertebrates—and even some invertebrate species—have the cognitive ability to discriminate among different quantities. For example, many kinds of studied animals can distinguish specific numbers of objects in…

Two new studies offer insight into why infection with SARS-CoV-2—the coronavirus that causes COVID-19—often leads to loss of smell, as well as why some people experience debilitating symptoms months after infection—a condition known as long COVID.…

Mercury and its compounds are highly toxic—that is, they cause harmful effects to living organisms. Mercury pollution is found in water, air, and soil worldwide. According to the United Nations Environment Programme, the top anthropogenic sources of…

Among the non-human animals that can be infected with—and become sick from—humans who have the SARS-CoV-2 virus that causes COVID-19 are deer, mink, hyenas, pigs, ferrets, dogs, cats, and primates such as rhesus macaque monkeys, baboons, and…

Food packaging prevents contamination and extends the shelf-life of food products, making food safe and available to the public. Common food-packaging materials include metals, glass, paper, and plastics. Of these, metals, glass, and recyclable…

Bats are members of the order Chiroptera, which is the second-largest order of living mammals. The geographic distribution of these flying mammals is tremendous as well, ranging from the limit of trees in the Northern Hemisphere to the southern tips…

Although cats are the number one lethal threat to birds, collisions with building glass are not far behind. The number of birds killed each year by glass collisions worldwide is estimated to be in the billons. In the United States, the U.S. Fish &…

Monarch butterflies (Danaus plexippus) exclusively consume milkweed plants (genus Asclepia) both for nutrition and to help deter predators. Milkweed plants contain toxins that accumulate in the butterfly larva, or caterpillars, as the insects feed;…

Genealogists and anthropologists have long disputed the provenance of domestic dogs (Canis lupus familiaris). Although genetic analyses and fossil evidence indicate that the domestic dog descended from the gray wolf (Canis lupus), the exact location…

Food waste occurs at all levels of the supply chain and beyond, from farm to table, for reasons ranging from spoilage to over-buying. The U.S. Department of Agriculture’s (USDA) Economic Research Service defines food waste as “the edible amount of…

A serious outbreak of equine herpesvirus type 1 (EHV-1), an infectious viral disease, is currently spreading among horse populations in Europe. This outbreak was first detected in Valencia, Spain, in February 2021 during a month-long equestrian…

Approximately 75% of flowering plants—including about a third of agricultural food crops—depend on the distribution of pollen by an array of animals known collectively as pollinators. These animals include insects such as bees and wasps…

The Antarctic ice sheet is the largest remnant of previous ice-age glaciations. Glaciers flow out from this ice sheet and feed into floating ice shelves along one-third of the Antarctic coastline. One of the largest ice shelves is the Filchner-Ronne…

In a breakthrough in the global fight against malaria, the World Health Organization (WHO) is recommending widespread administration of the first-ever malaria vaccine. This first-generation vaccine is intended for children considered to be at high…

Pasta comes in various sizes and shapes, ranging from long and flat (such as linguine and spaghetti) to short types in the shape of shells (conchiglie), corkscrews (fusilli), and many others. Shaped pastas contain a larger volume of air, resulting…

In recent years, researchers have made considerable progress toward producing renewable energy in the form of hydrogen fuel through the electrolysis of water. In the most basic electrolytic cell, an electric current drives a chemical reaction at two…

The Hudson River estuary in the United States experiences a tide from New York Harbor (river kilometer 0/river mile 0) to Troy, New York (river kilometer 244/river mile 152). In the lower 60 kilometers (37 miles) of the Hudson River, the water is…

Atmospheric ozone plays a critical role in the biosphere by absorbing harmful ultraviolet radiation in the stratosphere—the layer of the atmosphere about 10 to 50 km (6 to 30 mi) above Earth’s surface. Since the adoption of the Montreal Protocol in…

The spotted hyena (Crocuta crocuta)—one of three species of hyenas found in Africa—is a highly social mammal that lives in large groups, or clans, containing at least 90 individuals. The social organization of spotted hyenas is more complex than the…

The diverse totality of microorganisms regularly found on and in the human body is collectively referred to as the human microbiota or microbial flora, with the largest microbial community in the body residing in the large intestine, or colon.…

In many animals, including humans, the sense of smell performs an important threat-detection function by helping to identify potential sources of harm, such as rotting food and toxic fumes. Little is known, however, about the initial neural…

According to the Intergovernmental Panel on Climate Change (IPCC), to avoid the major impacts of climate change, such as deadly heat and decreased crop yields, will require limiting global warming to a maximum increase of 1.5 to 2.0 degrees Celsius.…

The American bald eagle (Haliaeetus leucocephalus) was once on the brink of extinction in North America. As a result of concerted conservation efforts, including the elimination of use of the pesticide DDT in the United States in 1972, the bald…

The taxonomic classification of whales continues to evolve as marine biologists glean new insights from investigations of the largest of all animals on Earth. Two recent whale discoveries—one concerning a new species, and the other dealing with…

Peatlands, also known as bogs and fens, are a type of wetland in which, over the course of hundreds to thousands of years, vegetation—mosses, sedges, trees, and other plants—have accumulated as partially decomposed organic matter. Peat itself covers…

The field of vaccination has been enhanced significantly by the successful development of two approved vaccines based on messenger RNA (mRNA) technologies. Prior to the COVID-19 pandemic that spread from China in 2019 to the rest of the world in…

The fossil record of sharks (members of the subclass Elasmobranchii within the class Chondrichthyes, or cartilaginous fishes) dates back more than 420 million years. Over the course of this time, sharks have been among the top predators found in the…

On April 7, 2021, the U.S. Centers for Disease Control and Prevention (CDC) announced that a genetic variant of SARS-CoV-2—the coronavirus that causes COVID-19—that was initially identified in the United Kingdom is the dominant form of the virus…

Scrap tires are a common waste material, although markets do exist. According to the U.S. Tire Manufacturers Association, of the roughly 270 million scrap rubber tires generated each year in this country, about 100 million tires are used as fuel;…

In response to the COVID-19 (coronavirus disease 2019) pandemic—which has dramatically affected the entire world, causing high morbidity, mortality, and massive social and economic disruption—and in addition to finding efficacious treatments for…

Researchers at Northwestern University, Evanston, Illinois, USA, have developed a virus catcher of sorts—that is, a sticky and absorbent surface coating that traps droplets and aerosols (microdroplets) that land on the coating. Most often, fine…

An investigation of 890-million-year-old limestone rocks excavated from the mountains of Canada's Northwest Territories has revealed possible evidence of the oldest animal life on Earth. Prior to this study, the oldest undisputed fossils of animal…

With a fossil record dating to the start of the Mesozoic era, approximately 250 million years ago, the tuatara (Sphenodon punctatus) is the sole extant representative of the reptilian order Rhynchocephalia. This unique reptile has an unusually long…

A clade of ancient birds known as lithornithids (chicken-sized, long-beaked birds), who lived approximately 40–70 million years ago, possessed a unique vibrotactile bill-tip organ that allowed these birds to detect vibrations in the ground. The…

Researchers at Purdue University in Indiana, United States, have developed the whitest white paint on record, based on its ultrahigh reflection rating. By incorporating a pigment called barium sulfate (BaSO4) at the highest concentration possible,…

Cosmochemists have discovered the oldest solid material known to exist on Earth. The material, stardust, consists of silicon carbide grains measuring around one micrometer in size. The grains date back approximately 7 billion years, or about 2.5…

There is a growing body of evidence that many of the thousands of prescription and over-the-counter medications ultimately make their way into water bodies and drinking-water supplies. Typical wastewater treatment plants may not be effective at…

Microplastics are raining down on national parks and other protected areas in the western United States at the rate of about 132 pieces of microplastic per square meter every day, according to a report in the journal Science (June 2020).…

Wildfires, also termed bushfires or forest fires, are currently devastating large swaths of land in Australia. Detrimental ecologic consequences of these uncontrolled combustions of forest fuels and vegetation are numerous. One of the most serious…

The American beech (Fagus grandifolia) is native to forest regions east of the Mississippi River and is a key tree species in the United States. In particular, it is very abundant from Ohio to the New England states. The tree is also found in the…

Scientists have suggested a possible connection between ancient Neandertals (Homo neanderthalensis) and the severity of disease in patients affected by COVID-19. In short, certain genes acquired from Neandertals during instances of interbreeding…

The novel coronavirus SARS-CoV-2 that emerged in central China in late 2019 and subsequently spread across the world in 2020 led to the COVID-19 pandemic. The emergence of a previously unknown pathogen—such as the novel coronavirus—that could affect…

The world’s oceans and coasts provide a natural sink for excess carbon in the atmosphere. Scientists refer to carbon that is captured and stored this way as blue carbon. Well-known blue-carbon examples include mangroves and salt marshes—wetland…

If you think converting seawater to fuels that can power ships is a fantasy, think again. Researchers at the U.S. Naval Research Laboratory in Washington, D.C., have, in fact, accomplished this feat. In addition, the U.S. Navy has received a patent…

Using an artificial intelligence technique known as deep learning and high-resolution remote sensing, scientists have counted and mapped the location of trees in 11,000 satellite images covering more than 1.3 million square kilometers (500,000…

There has been substantial progress in the fight against certain drug-resistant organisms that cause serious, often fatal, diseases. However, two drug-resistant microbes—specifically, Candida auris (a fungal yeast) and Acinetobacter (a genus of…

Sickle cell disease, also termed sickle cell anemia, is a genetic disorder in which hypoxia, or oxygen deprivation, causes red blood cells (erythrocytes) to assume a rigid sickle shape, blocking blood flow within blood vessels. The disease results…

Fingerprint identification is a widely used forensic method for linking an individual to a crime scene. Investigators at a crime scene can find invisible (latent) fingerprints, which consist of natural skin oils, by "dusting" surfaces with carbon…

Mucus produced by the common garden snail (Helix aspersa) is green. The slime is not actually green in color but is “green” in terms of its environmentally friendly chemistry. It turns out that this snail’s mucus has chemical properties as a…

Life on Earth has been punctuated by a number of catastrophic mass extinctions throughout history. During these events, diverse taxonomic groups collapsed from the relatively rapid and widespread extinction of large numbers of species. Precipitated…

Heroin (C21H23NO5) is a white, crystalline powder synthesized from morphine, a natural alkaloid extracted from the seedpod of the Asian opium poppy plant, Papaver somniferum. It is a powerful opioid drug prepared by the addition of two acetyl groups…

A class of chemicals known as per- and polyfluoroalkyl compounds (PFAS) are particularly worrisome in the environment because they do not biodegrade. For this reason, scientists often refer to PFAS as “forever chemicals.” PFAS’s staying power…

Conservationists are alarmed by significant reductions in insect populations worldwide. Based on recent biodiversity surveys and entomological studies, scientists estimate that more than 40% of the world's insect species (class Insecta, phylum…

The majority of toxic pollution in the United States could potentially be eliminated by requiring a small number of extreme polluters to release pollutants at levels in line with those of comparable industrial facilities, according to a recent study…

Of the three extant elephant species, two inhabit Africa: the African bush or savanna elephant, Loxodonta africana; and the smaller African forest elephant, L. cyclotis. The African bush elephant is the largest living land mammal and is primarily…

Naturally ventilating a house, such as by opening doors and windows, has long been considered an effective strategy for exhausting indoor air pollutants. However, according to researchers reporting in the journal Science Advances (February 2020),…

Famously durable, diamond is the hardest natural substance that occurs in any significant abundance on Earth. Yet according to a new study, on the nanoscale—a scale size of just billionths of a meter—diamond can, in fact, be bent and deformed. This…

All of the many diverse breeds of dogs, including both domestic and wild dogs (wolves, coyotes, foxes, jackals, and dingoes), belong to the genus Canis in the mammalian family Canidae. One intriguing example of an obscure wild dog is the New Guinea…

Over thousands of years of study of the human body through dissection and, more recently, modern-day imaging techniques, scientists have observed and analyzed various glands—that is, structures or organs that produce and secrete a substance or…

Scientists have identified the earliest known fossil of a modern bird. The fossil remains—comprising an almost-complete skull and a few limb bones embedded in rock—were discovered in a limestone quarry in Belgium. Estimated to be approximately 66.7…

During the initial stages of the COVID-19 pandemic, most restaurants and other dining facilities were shut down to contain the spread of the SARS-CoV-2 virus. By July 2020, however, indoor dining once again became an option for many…

Since the start of the COVID-19 (coronavirus disease 2019) pandemic, doctors and epidemiologists have identified a number of underlying medical conditions that are significantly correlated with severe illness from COVID-19. One such notable…

As offices, schools, health clubs, restaurants, hotels, and other facilities gradually reopen after shutdowns related to the COVID-19 pandemic, the public may confront yet another unmitigated health hazard: unsafe water from dormant or underused…

Over the course of history, smallpox has been among the most feared diseases of humankind. Caused by the variola virus (a DNA-containing member of the Poxviridae family) and spread by transfer through respiratory droplets during face-to-face…

The Tasmanian devil (Sarcophilus harrisii) is the world's largest living marsupial carnivore. For tens of thousands of years, this fierce animal could be found throughout the continent of Australia, as well as inhabiting the island of Tasmania.…

Stellar explosions known as supernovae may be behind several anomalous rises in radiocarbon captured in tree rings over the past 40,000 years, according to a recent study that adds mounting evidence to the hypothesis that supernovae can impact…

Occurring in mammary glands and closely associated tissues, breast cancer is the most common cancer observed in women. For example, in the United States, approximately 1 in 8 women (about 12%) will develop invasive breast cancer over the course of…

Members of the order Pristiophoriformes within the vertebrate subphylum comprise an unusual group of sharks. Collectively known as sawsharks, these marine fishes are distinguishable from other elasmobranchs (sharks, skates, and rays) by a number of…

A form of ultraviolet (UV) light holds promise as an innovative way to neutralize airborne SARS-CoV-2 particles and other viruses, potentially helping slow the COVID-19 pandemic that, to date, has caused over 1.3 million deaths globally. More…

Researchers from Drexel University in Pennsylvania, USA, have synthesized conductive and layered 2D materials known as MXenes (pronounced maxenes) using a water-free process. In doing so, scientists have opened up potential uses of MXenes as…

Poliomyelitis, more commonly called polio, is a devastating infectious disease of the central nervous system caused by the poliovirus (a type of enterovirus), which has three types in the wild (types 1, 2, and 3). Wild types 2 and 3 were declared…

Many trees in forests worldwide rely on natural fires to create growing conditions necessary to perpetuate the ecosystem, or to stimulate germination. However, for more than 100 years, humans have been suppressing frequent natural low-intensity…

Persistent changes in the Earth's climate that have been occurring primarily as a result of human-caused greenhouse-gas emissions since the mid-twentieth century have led to significant increases in infectious diseases in wildlife, both in terms of…

The Ebola virus comprises a group of pathogenic agents that cause severe and deadly hemorrhagic fevers in humans and other primates. During 2014 and 2015, an Ebola virus epidemic in West Africa—predominantly, the countries of Guinea, Liberia, and…

The United Nations has proclaimed 2019 the International Year of the Periodic Table of Chemical Elements (IYPT2019). The same year also marks the 150th anniversary of the publication of Russian chemist Dmitri Mendeleev’s periodic table, containing…

The Joshua tree (Yucca brevifolia) is a remarkable evergreen, treelike plant found only in the southwestern United States. It was named by Mormon settlers in the early 1800s. Upon seeing the limbs of this plant branching upwards to heaven, the…

Collectively, members of the class Amphibia are facing massive reductions in total numbers, and the overall biodiversity of amphibians across the globe is under threat. Scientists have determined that global climate change and habitat destruction…

The cancer death rate in the United States has fallen by 27% since 1991. According to the American Cancer Society, which compiled the data over a 25-year period from 1991 to 2016, a total of 2.6 million fewer individuals have died from cancer in the…

Charles Robert Darwin (February 12, 1809 – April 19, 1882) is one of the most celebrated and eminent scientists of the past few centuries, with his broadest and most notable influence arising from his theory of evolution by means of natural…

Plastic is a ubiquitous and life-saving product, but it is also rapidly becoming a significant environmental problem. Globally, less than 10 percent of plastics are recycled, about 12 percent are incinerated, and the vast majority are disposed of in…

It has been a long-held belief that, as a result of hunting habits, early humans were partly or even primarily responsible for the decline and eventual extinction of most of the largest mammalian species that inhabited ancient Africa. These large…

For the first time, scientists have observed two molecules meeting and reacting to form new molecules. A team of chemists used lasers to slow down interacting molecules to temperatures far colder than outer space, enabling the team to observe a…

The critically endangered northern white rhinoceros (Ceratotherium simum cottoni) is a subspecies of white rhino that is on the brink of complete extinction, with only two individuals left in captivity and no known members reported in the wild. The…

Trees provide substantial benefits to the environment. In addition to improving air quality, reducing stormwater runoff, serving as a wildlife habitat, and sequestering carbon by absorbing carbon dioxide, trees also cool the atmosphere through shade…

A compound found in cranberries, called cranberry proanthocyanidin (cPAC), when used in combination with antibiotics, such as tetracycline, prevents resistance to antibiotics in Escherichia coli and Pseudomonas aeruginosa, according to researchers…

The International Union for Conservation of Nature (IUCN)—the global authority on the status of the natural world—estimates that approximately 5–10% of the world's insect species (class Insecta, phylum Arthropoda) are threatened and facing…

Eastern equine encephalitis is a rare infectious viral disease that primarily affects humans and equines (horses, mules, donkeys, and zebras). It is caused by a mosquito-borne virus (arbovirus) that is native to the eastern half of the United…

Fentanyl is a synthetic opioid analgesic (pain reliever) that resembles morphine in its action. However, its drug potency is approximately 50 to 100 times more powerful than that of morphine, leading to high rates of both addiction and overdose…

Photosynthesis is a key natural process utilized by plants and is necessary for proper plant growth. Specifically, photosynthesis uses light to manufacture chemical compounds, including organic compounds—primarily carbohydrates—that are derived from…

All freshwater comes from precipitation over land, which is distributed on Earth as blue and green water. Blue water—that is, surface and groundwater—is stored as freshwater in lakes, streams, ice, and snow, as well as below ground. Green water is…

The four main blood types (blood groups) found in humans are A, B, AB, and O. Two particular antigens (A and B) determine the specific blood type—A antigen is present in type A blood; B antigen is present in type B blood; both A and B antigens are…

The Komodo dragon (Varanus komodoensis), a type of monitor lizard belonging to the reptilian order Squamata, is a tremendously powerful carnivorous predator. The creature is indigenous to a small number of Indonesian islands, including Komodo, and…

Researchers at Duke University in North Carolina (United States) have developed a test for distinguishing lead isotopes found in coal fly ash from lead isotopes found in other lead-containing sources, such as paint. Fly ash is a fine particulate…

Researchers have produced carbon chips from waste plastic bags for use in making anodes for lithium-ion batteries, according to a report in ACS Omega (December 2018). For the most part, it is very difficult to break down (depolymerize) plastics into…