Less bird diversity in city forests

Image credit: Kev

A new study led by Lund University in Sweden shows that cities negatively affect the diversity of birds. There are significantly fewer bird species in urban forests compared with forests in the countryside - even if the forest areas are of the same quality.

The researchers examined 459 natural woodlands located in or near 32 cities in southern Sweden. They counted the occurrence of different bird species, and the result is clear: in natural forests located in a city center, there are on average a quarter fewer species of forest birds compared to forests outside the city. In terms of endangered species, about half as many species were found in urban forests compared to rural forests.

The results deepen our knowledge of the impact of cities on biodiversity, says William Sidemo Holm, one of the researchers behind the study. It is already well known that urbanization is one of the main driving forces behind the loss of biodiversity, as cities spread out across the globe. What is not as well known, however, is how cities affect protected natural areas in a city.

“Our study demonstrates that you cannot surround nature with urban development and believe that it will remain as it is, there is going to be a negative effect”, says William Sidemo Holm, who worked on the study during his time as a doctoral student at Lund University.

Birth of a sibling triggers long-lasting stress in young bonobos

Young bonobos as old as eight years suffer long-lasting stress after the birth of a sibling. 
Credit: MPI of Animal Behavior/ Christian Ziegler

In any family, the birth of a child is a transformative event, often greeted with positive feelings from parents—and mixed feelings from siblings. The arrival of a new brother or sister, and the loss of parental attention that comes with it, is stressful for any first-born child. Now, scientists have shown that it is not just humans who have trouble becoming siblings. Bonobos, our closest living relatives, also experience stress in the transition to siblinghood. Following the birth of a sibling, young bonobos had five times higher levels of the stress hormone cortisol and a reduced immune response, which lingered for months. The international team of researchers behind the study were able to show that the stress response was due to the birth of siblings, and not to the natural weaning process that young bonobos inevitably go through. The study on wild bonobos, which is the first to investigate physiological changes in an animal as it transitions to siblinghood, reveals similarities between humans and bonobos—and an evolutionary history behind the stressful event of becoming a sibling.

Bonobos (Pan paniscus) are a species of great ape found only in the Congolese rainforest. Like humans, bonobos and other great apes take an unusually long time to reach independence. Bonobos rely on their mothers for food and protection for eight years and only reach full adulthood at 12 years. While in most animals, offspring are weaned before the mother gives birth to another infant. In bonobos, maturation is slow and the birth of another baby happens long before the older infant has become independent—setting the scene for sibling rivalry.

How fish survive the extreme pressures of life in the oceans

Photo credit: Milos Prelevic

Scientists have discovered how a chemical in the cells of marine organisms enables them to survive the high pressures found in the deep oceans.

The deeper that sea creatures live, the more inhospitable and extreme the environment they must cope with. In one of the deepest points in the Pacific - the Mariana Trench, 11 kilometers below the sea surface - the pressure is 1.1 kbar or eight tons per square inch. That is a 1,100-fold increase of the pressure experienced at the Earth’s surface.

Under normal or atmospheric pressure, water molecules form a tetrahedron-like network. At high pressure, though, the network of water molecules begins to distort and change shape. When this happens to the water inside living cells, it prevents vital bio-chemical processes from taking place - and kills the organism.

Our study provides a bridge between water under pressure at the molecular level and the wonderful ability of organisms which thrive under high pressure in depths of the oceans.

In reporting their findings, the researchers in Leeds have for the first time been able to provide an explanation of how a molecule found in the cells of marine organisms counteracts the effect of external pressure on the water molecules.

Dead fish breathe new life into the evolutionary origin of fins and limbs

The holotype specimen of the fossil Tujiaaspis vividus from 436 million year old rocks of Hunan Province and Chongqing, China.
Credit: Zhikun Gai

A trove of fossils in China, unearthed in rock dating back some 436 million years, have revealed for the first time that the mysterious galeaspids, a jawless freshwater fish, possessed paired fins.

The discovery, by an international team, led by Min Zhu of the Institute of Vertebrate Paleontology and Palaeoanthropology, Bejiing and Professor Philip Donoghue from the University of Bristol’s School of Earth Sciences, shows the primitive condition of paired fins before they separated into pectoral and pelvic fins, the forerunner to arms and legs.

Until now, the only surviving fossils of galeaspids were heads, but these new fossils originating in the rocks of Hunan Province and Chongqing and named Tujiaaspis after the indigenous Tujia people who live in this region, contain their whole bodies.

Theories abound on the evolutionary beginnings of vertebrate fins and limbs – the evolutionary precursors of arms and legs - mostly based on comparative embryology. There is a rich fossil record, but early vertebrates either had fins or they didn’t. There was little evidence for their gradual evolution.

Scientists bring the fusion energy that lights the sun and stars closer to reality on Earth

Physicist Min-Gu Yoo with slides from his paper in background.
Photo credit: Elle Starkman/PPPL Office of Communications; collage by Kiran Sudarsanan

Physicists at the U.S. Department of Energy’s (DOE) Princeton Plasma Physics Laboratory (PPPL) have proposed the source of the sudden and puzzling collapse of heat that precedes disruptions that can damage doughnut-shaped tokamak fusion facilities. Coping with the source could overcome one of the most critical challenges that future fusion facilities will face and bring closer to reality the production on Earth of the fusion energy that drives the sun and stars.

Researchers traced the collapse to the 3D disordering of the strong magnetic fields that bottle up the hot, charged plasma gas that fuels the reactions. “We proposed a novel way to understand the [disordered] field lines, which was usually ignored or poorly modeled in the previous studies,” said Min-Gu Yoo, a post-doctoral researcher at PPPL and lead author of a Physics of Plasmas paper selected as an editor’s pick together with a figure placed on the cover of the July issue. Yoo has since become a staff scientist at General Atomics in San Diego.

The strong magnetic fields substitute in fusion facilities for the immense gravity that holds fusion reactions in place in celestial bodies. But when disordered by plasma instability in laboratory experiments the field lines allow the superhot plasma heat to rapidly escape confinement. Such million-degree heat crushes plasma particles together to release fusion energy and can strike and damage fusion facility walls when released from confinement.

Set up reserve lab capacity now for faster response to next pandemic, say researchers

Female scientist in laboratory 
Photo credit: Diane Serik

The researchers, who were on the front line of the UK’s early response to COVID-19 in 2020, say a system of reservist lab scientists should to be set up now to provide surge capacity that will help the country respond faster – and more effectively – to future outbreaks of infectious disease.

They considered a number of options for providing scientific surge capacity and concluded that the best scenario would be a mix of highly skilled paid reservists, and volunteers who could be called on when required and trained rapidly.

In their report, published today in the journal The BMJ, the researchers say the lack of early COVID-19 PCR testing capacity had a knock-on effect on other health services in 2020. This included delaying the ability to make sure hospitals were COVID-secure and patients had surgery as safely as possible, and slowing down the identification of people with COVID-19 in the community – which delayed contact tracing.

“Because COVID-19 testing wasn’t scaled up quickly enough, we couldn’t detect all cases quickly enough to try and stop the spread of the disease,” said Dr Jordan Skittrall in the University of Cambridge’s Department of Pathology and first author of the report.

“It was frustrating to hear politicians’ promises to repeatedly scale up COVID-19 testing capacity during the early stage of the pandemic. The scale-up was extremely challenging: a lot of expertise is needed to get the tests working in the early stages of dealing with a new pathogen,” he added.

Scientists chip away at a metallic mystery, one atom at a time

In this photo from 2020, Christopher Barr, right, a former Sandia National Laboratories postdoctoral researcher, and University of California, Irvine, professor Shen Dillon operate the In-situ Ion Irradiation Transmission Electron Microscope. Barr was part of a Sandia team that used the one-of-a-kind microscope to study atomic-scale radiation effects on metal.
Photo credit: Lonnie Anderson

Gray and white flecks skitter erratically on a computer screen. A towering microscope looms over a landscape of electronic and optical equipment. Inside the microscope, high-energy, accelerated ions bombard a flake of platinum thinner than a hair on a mosquito’s back. Meanwhile, a team of scientists studies the seemingly chaotic display, searching for clues to explain how and why materials degrade in extreme environments.

Based at Sandia, these scientists believe the key to preventing large-scale, catastrophic failures in bridges, airplanes and power plants is to look — very closely — at damage as it first appears at the atomic and nanoscale levels.

“As humans, we see the physical space around us, and we imagine that everything is permanent,” Sandia materials scientist Brad Boyce said. “We see the table, the chair, the lamp, the lights, and we imagine it’s always going to be there, and it’s stable. But we also have this human experience that things around us can unexpectedly break. And that’s the evidence that these things aren’t really stable at all. The reality is many of the materials around us are unstable.”

No difference between spinal versus general anesthesia in patients having hip fracture surgery

Image credit: Fernando zhiminaicela

There are no differences in the safety or effectiveness of the two most common types of anesthetics (spinal versus general anesthesia) in patients undergoing hip fracture surgery, according to the findings of a new study led by the University of Bristol in collaboration with University of Warwick researchers. The findings, published in the British Journal of Anesthesia, analyzed previously published data on nearly 4,000 hip fracture patients.

The research was funded by The Academy of Medical Sciences and supported by the NIHR Biomedical Research Centre at University Hospitals Bristol NHS Foundation Trust and the University of Bristol.

Hip fractures are devastating injuries and remain one of the largest healthcare challenges of the twenty-first century. The incidence increases with advancing age and the number of hip fractures is expected to rise to 6.26 million per year in 2050. In 2017, hip fractures cost the National Health Service (NHS) over £1 billion, which is projected to increase to £5.6 billion in 2033. Patients with hip fractures have a relatively high risk of dying within a year of their injury.

Almost all patients with a hip fracture undergo surgery, requiring anesthesia to be performed so that surgery is safe and not painful. Nearly all patients will receive either spinal or general anesthesia. Given the risk profile of hip fracture patients (older age, frailty, and comorbidities like cardiac and respiratory diseases), surgery is associated with a high risk of developing post-operative complications including delirium, myocardial infarction, pneumonia, stroke, and death.

After wildfires, do microbes exhale potent greenhouse gas?

UCR mycologist and project lead Sydney Glassman sampling burn scar soil.
Photo credit: Sydney Glassman/UCR

Laughing gas is no laughing matter — nitrous oxide is a greenhouse gas with 300 times the warming potential of carbon dioxide. Scientists are racing to learn whether microorganisms send more of it into the atmosphere after wildfires.

A research team led by UC Riverside mycologist Sydney Glassman will spend the next three years answering this question, examining how bacteria, viruses, fungi and archaea work together in post-fire soils to affect nitrous oxide emissions.

Their work is supported by a new $3.1 million grant from the U.S. Department of Energy.

“Because carbon dioxide is the largest contributor to global warming, it’s easy to focus on,” Glassman said.

“Nitrogen in the form of nitrous oxide, and the microbes that regulate it, are a less well-studied aspect of the problem, but an aspect we must solve to more fully understand how the planet is changing, and how much we can expect it to keep changing,” she said.

Novel Carrier Doping in p-type Semiconductors Enhances Photovoltaic Device Performance by Increasing Hole Concentration

The carrier concentration and conductivity in p-type monovalent copper semiconductors can be significantly enhanced by adding alkali metal impurities, as shown recently by Tokyo Tech researchers. Doping with isovalent and larger-sized alkali metal ions effectively increased the free charge carrier concentration and the mechanism was unraveled by their theoretical calculations. Their carrier doping technology enables high carrier concentration and high mobility p-type thin films to be prepared from the solution process, with photovoltaic device applications.

Perovskite solar cells have been the subject of much research as the next generation of photovoltaic devices. However, many challenges remain to be overcome for the practical application. One of them concerns the hole transport layer (p-type semiconductor) in photovoltaic cells that carries holes generated by light to the electrode. In conventional p-type organic transport semiconductors, hole dopants are chemically reactive and degrade the photovoltaic device. Inorganic p-type semiconductors, which are chemically stable, are promising alternatives, but fabrication of conventional inorganic p-type semiconductors requires high temperature treatment. In this regard, the p-type inorganic semiconductors that can be fabricated at low temperatures and have excellent hole transport ability have been desired.

Inorganic p-type copper iodide (CuI) semiconductor is a leading candidate for such hole transport materials in photovoltaic device applications. In this material, native defects give rise to charge imbalance and free charge carriers. However, the overall number of defects is generally too low for satisfactory device performance.