Biology

Time to end the cruel ban on using cannabis therapy for epilepsy

Genetics - вт, 2018-06-19 13:19
Ill-conceived and outdated drug laws in the UK are denying children with severe epilepsy vital medicinal cannabis treatments. That must change, says David Nutt
Категории: Biology

Football’s a mess: don’t let technology spoil that

Genetics - вт, 2018-06-19 11:00
The video-assisted refereeing technology being introduced in this year's World Cup will supposedly cut errors – but that ignores what makes football great
Категории: Biology

A robot has performed eye surgery on humans for the first time

Genetics - вт, 2018-06-19 10:00
For the first time, six people have had eye surgery performed by a robot that was able to filter out the tremors from a surgeon's hand
Категории: Biology

These hyper-real androids are climbing out of the uncanny valley

Genetics - вт, 2018-06-19 09:00
UK robotics firm Engineered Arts is making androids for film launches… and sometimes leaving them in the pub
Категории: Biology

Classes and continua of hippocampal CA1 inhibitory neurons revealed by single-cell transcriptomics

PLOS Biology (new articles) - пн, 2018-06-18 23:00

by Kenneth D. Harris, Hannah Hochgerner, Nathan G. Skene, Lorenza Magno, Linda Katona, Carolina Bengtsson Gonzales, Peter Somogyi, Nicoletta Kessaris, Sten Linnarsson, Jens Hjerling-Leffler

Understanding any brain circuit will require a categorization of its constituent neurons. In hippocampal area CA1, at least 23 classes of GABAergic neuron have been proposed to date. However, this list may be incomplete; additionally, it is unclear whether discrete classes are sufficient to describe the diversity of cortical inhibitory neurons or whether continuous modes of variability are also required. We studied the transcriptomes of 3,663 CA1 inhibitory cells, revealing 10 major GABAergic groups that divided into 49 fine-scale clusters. All previously described and several novel cell classes were identified, with three previously described classes unexpectedly found to be identical. A division into discrete classes, however, was not sufficient to describe the diversity of these cells, as continuous variation also occurred between and within classes. Latent factor analysis revealed that a single continuous variable could predict the expression levels of several genes, which correlated similarly with it across multiple cell types. Analysis of the genes correlating with this variable suggested it reflects a range from metabolically highly active faster-spiking cells that proximally target pyramidal cells to slower-spiking cells targeting distal dendrites or interneurons. These results elucidate the complexity of inhibitory neurons in one of the simplest cortical structures and show that characterizing these cells requires continuous modes of variation as well as discrete cell classes.
Категории: Biology, Journals

Reporting bias in the literature on the associations of health-related behaviors and statins with cardiovascular disease and all-cause mortality

PLOS Biology (new articles) - пн, 2018-06-18 23:00

by Leandro Fórnias Machado de Rezende, Juan Pablo Rey-López, Thiago Hérick de Sá, Nicholas Chartres, Alice Fabbri, Lauren Powell, Emmanuel Stamatakis, Lisa Bero

Reporting bias in the literature occurs when there is selective revealing or suppression of results, influenced by the direction of findings. We assessed the risk of reporting bias in the epidemiological literature on health-related behavior (tobacco, alcohol, diet, physical activity, and sedentary behavior) and cardiovascular disease mortality and all-cause mortality and provided a comparative assessment of reporting bias between health-related behavior and statin (in primary prevention) meta-analyses. We searched Medline, Embase, Cochrane Methodology Register Database, and Web of Science for systematic reviews synthesizing the associations of health-related behavior and statins with cardiovascular disease mortality and all-cause mortality published between 2010 and 2016. Risk of bias in systematic reviews was assessed using the ROBIS tool. Reporting bias in the literature was evaluated via small-study effect and excess significance tests. We included 49 systematic reviews in our study. The majority of these reviews exhibited a high overall risk of bias, with a higher extent in health-related behavior reviews, relative to statins. We reperformed 111 meta-analyses conducted across these reviews, of which 65% had statistically significant results (P < 0.05). Around 22% of health-related behavior meta-analyses showed small-study effect, as compared to none of statin meta-analyses. Physical activity and the smoking research areas had more than 40% of meta-analyses with small-study effect. We found evidence of excess significance in 26% of health-related behavior meta-analyses, as compared to none of statin meta-analyses. Half of the meta-analyses from physical activity, 26% from diet, 18% from sedentary behavior, 14% for smoking, and 12% from alcohol showed evidence of excess significance bias. These biases may be distorting the body of evidence available by providing inaccurate estimates of preventive effects on cardiovascular and all-cause mortality.
Категории: Biology, Journals

Trump has directed the US military to establish a Space Force

Genetics - пн, 2018-06-18 20:36
President Trump has announced the creation of a Space Force, the first new US military branch since 1947, but it’s not yet clear what this new corps will do
Категории: Biology

HIV prevention drugs could delay diagnosis if you get infected

Genetics - пн, 2018-06-18 19:35
HIV tests may be giving incorrect results for people taking PrEP to avoid getting the virus, meaning they may be HIV positive for months without knowing
Категории: Biology

Being a feminist may subconsciously protect you from stereotypes

Genetics - пн, 2018-06-18 18:00
Negative stereotypes can detrimentally change your behaviour. But a study suggests that feminists may be protected from the idea that women are worse at maths
Категории: Biology

Male peacocks can make females’ heads vibrate at a distance

Genetics - пн, 2018-06-18 17:15
Peahens have fan-shaped crests on their heads, and it seems males can make these crests resonate by making a specific noise with their tails
Категории: Biology

Stars gravitate to Stephen Hawking’s memorial service

Genetics - пн, 2018-06-18 17:00
There was only one Stephen Hawking but there were a thousand ways to celebrate a genius and science’s only global celebrity at London’s Westminster Abbey
Категории: Biology

The first Americans had pet dogs 1000 years earlier than thought

Genetics - пн, 2018-06-18 14:44
There were domestic dogs in North America 10,200 years ago, according to a re-examination of an ancient dog skeleton that looks like a small English setter
Категории: Biology

Colony ship to nearest star only needs crew of 100 to survive

Genetics - пн, 2018-06-18 12:58
A mission to Proxima Centauri b, the closest Earth-like exoplanet, would take over 6000 years – but you only need a small crew to get started
Категории: Biology

Following trends and easy answers isn’t the way to a good life

Genetics - пн, 2018-06-18 12:00
Vegan clothes, biofuel and wood-burning stoves have all been offered up as ethical, environmental choices – but the evidence behind them is much more murky
Категории: Biology

Changing our minds about psychedelics takes a great guide

Genetics - пн, 2018-06-18 11:00
A book on learning to open our minds to psychedelics as they find a new, more scientific place in our society makes for a fantastic personal story
Категории: Biology

How Charles Dickens became a man of science

Genetics - вс, 2018-06-17 12:00
We think we know Charles Dickens, but his writings on chemistry and energy at a new London exhibition cast him in a very different light
Категории: Biology

Get food on the go with this roaming robot table

Genetics - вс, 2018-06-17 09:00
Make sure nobody goes hungry during your next Netflix binge with a snack-laden room rover
Категории: Biology

Westworld: a complex tale of robot awakening has us riveted

Genetics - сб, 2018-06-16 12:00
As TV hit Westworld's robots come to some awkward conclusions about their true nature in time for the season finale, we're still hooked by the show's sheer smartness
Категории: Biology

Knowing your DNA can help you stick to a healthier lifestyle

Genetics - сб, 2018-06-16 01:01
When people are advised to live more healthily, they usually give up quickly. Now a study suggests that genetic data can persuade people to make lasting changes
Категории: Biology

Is the sky the limit? On the expansion threshold of a species’ range

PLOS Biology (new articles) - пт, 2018-06-15 23:00

by Jitka Polechová

More than 100 years after Grigg’s influential analysis of species’ borders, the causes of limits to species’ ranges still represent a puzzle that has never been understood with clarity. The topic has become especially important recently as many scientists have become interested in the potential for species’ ranges to shift in response to climate change—and yet nearly all of those studies fail to recognise or incorporate evolutionary genetics in a way that relates to theoretical developments. I show that range margins can be understood based on just two measurable parameters: (i) the fitness cost of dispersal—a measure of environmental heterogeneity—and (ii) the strength of genetic drift, which reduces genetic diversity. Together, these two parameters define an ‘expansion threshold’: adaptation fails when genetic drift reduces genetic diversity below that required for adaptation to a heterogeneous environment. When the key parameters drop below this expansion threshold locally, a sharp range margin forms. When they drop below this threshold throughout the species’ range, adaptation collapses everywhere, resulting in either extinction or formation of a fragmented metapopulation. Because the effects of dispersal differ fundamentally with dimension, the second parameter—the strength of genetic drift—is qualitatively different compared to a linear habitat. In two-dimensional habitats, genetic drift becomes effectively independent of selection. It decreases with ‘neighbourhood size’—the number of individuals accessible by dispersal within one generation. Moreover, in contrast to earlier predictions, which neglected evolution of genetic variance and/or stochasticity in two dimensions, dispersal into small marginal populations aids adaptation. This is because the reduction of both genetic and demographic stochasticity has a stronger effect than the cost of dispersal through increased maladaptation. The expansion threshold thus provides a novel, theoretically justified, and testable prediction for formation of the range margin and collapse of the species’ range.
Категории: Biology, Journals