12,809 research outputs found
Winning Afghan ‘hearts and minds’? Time to leave Afghanistan
‘We try to help them … but it just seems pointless’ one British solider says, referring to the battle for ‘hearts and minds’ in Afghanistan. The biggest problem, says another, is “convincing the locals to help themselves.
Cyber terrorism and war, the looming threat to the industrialised state
Earlier this month the EastWest Institute held its second worldwide summit on cyber security. Hundreds of government and industry leaders, from over 43 countries, attended to discuss the looming threat of increasing war and criminality within the cyber domain
Shifting ranges and conservation challenges for lemurs in the face of climate change.
Geospatial modeling is one of the most powerful tools available to conservation biologists for estimating current species ranges of Earth's biodiversity. Now, with the advantage of predictive climate models, these methods can be deployed for understanding future impacts on threatened biota. Here, we employ predictive modeling under a conservative estimate of future climate change to examine impacts on the future abundance and geographic distributions of Malagasy lemurs. Using distribution data from the primary literature, we employed ensemble species distribution models and geospatial analyses to predict future changes in species distributions. Current species distribution models (SDMs) were created within the BIOMOD2 framework that capitalizes on ten widely used modeling techniques. Future and current SDMs were then subtracted from each other, and areas of contraction, expansion, and stability were calculated. Model overprediction is a common issue associated Malagasy taxa. Accordingly, we introduce novel methods for incorporating biological data on dispersal potential to better inform the selection of pseudo-absence points. This study predicts that 60% of the 57 species examined will experience a considerable range of reductions in the next seventy years entirely due to future climate change. Of these species, range sizes are predicted to decrease by an average of 59.6%. Nine lemur species (16%) are predicted to expand their ranges, and 13 species (22.8%) distribution sizes were predicted to be stable through time. Species ranges will experience severe shifts, typically contractions, and for the majority of lemur species, geographic distributions will be considerably altered. We identify three areas in dire need of protection, concluding that strategically managed forest corridors must be a key component of lemur and other biodiversity conservation strategies. This recommendation is all the more urgent given that the results presented here do not take into account patterns of ongoing habitat destruction relating to human activities
Disrupted in schizophrenia 1 and synaptic function in the mammalian central nervous system
This is the final version of the article. Available from the publisher via the DOI in this record.The disrupted in schizophrenia 1 (DISC1) gene is found at the breakpoint of an inherited chromosomal translocation, and segregates with major mental illnesses. Its potential role in central nervous system (CNS) malfunction has triggered intensive investigation of the biological roles played by DISC1, with the hope that this may shed new light on the pathobiology of psychiatric disease. Such work has ranged from investigations of animal behavior to detailed molecular-level analysis of the assemblies that DISC1 forms with other proteins. Here, we discuss the evidence for a role of DISC1 in synaptic function in the mammalian CNS.M. Kurihara was supported by a Medical Research Council Industrial collaborative
studentship in collaboration with Pfizer, who also supported aspects
of DISC1-related work in A. D. Randall’s laborator
Voltage- and Temperature-Dependent Allosteric Modulation of α7 Nicotinic Receptors by PNU120596
This is the final version of the article. Available from Frontiers Media via the DOI in this record.Alpha7 nicotinic acetylcholine receptors (α7 nAChR) are widely distributed throughout the central nervous system and are found at particularly high levels in the hippocampus and cortex. Several lines of evidence indicate that pharmacological enhancement of α7 nAChRs function could be a potential therapeutic route to alleviate disease-related cognitive deficits. A recent pharmacological approach adopted to increase α7 nAChR activity has been to identify selective positive allosteric modulators (PAMs). α7 nAChR PAMs have been divided into two classes: type I PAMs increase agonist potency with only subtle effects on kinetics, whereas type II agents produce additional dramatic effects on desensitization and deactivation kinetics. Here we report novel observations concerning the pharmacology of the canonical type II PAM, PNU120596. Using patch clamp analysis of acetylcholine (ACh)-mediated currents through recombinant rat α7 nAChR we show that positive allosteric modulation measured in two different ways is greatly attenuated when the temperature is raised to near physiological levels. Furthermore, PNU120596 largely removes the strong inward rectification usually exhibited by α7 nAChR-mediated responses
Murine myoblast migration: influence of replicative ageing and nutrition
Cell migration is central to skeletal muscle repair following damage. Leucine and β-Hydroxy β-methylbutyric acid (HMB) are supplements consumed for recovery from muscle damaging exercise in humans, however, their impact on muscle cell migration with age is not yet understood. We hypothesised that replicatively aged (“aged”; P46–P48) myoblasts would be less efficient at basal and supplemented repair versus parental controls (“control”; P12–P16). Aged and control myoblasts were scratch-damaged and migration velocity, directionality and distance assessed over 48 h in the absence and presence of leucine (10 mM) or HMB (10 mM) ± PI3K/Akt (LY294002 10 μM), ERK (PD98059 5 μM) or mTOR (rapamycin 0.5 μM) inhibition. Opposing our hypothesis, aged cells displayed increased velocities, directionality and distance migrated (P < 0.001) versus control. Leucine and HMB significantly increased (P < 0.001) the same parameters in control cells. The supplements were with smaller, albeit significant impact on aged cell velocity (P < 0.001) and in the presence of HMB only, distance (P = 0.041). Inhibitor studies revealed that, PI3K and ERK activation were essential for velocity, directionality and migration distance of aged cells in basal conditions, whereas mTOR was important for directionality only. While PI3K activation was critical for all parameters in control cells (P < 0.001), inhibition of ERK or mTOR improved, rather than reduced, control cell migration distance. Enhanced basal velocity, directionality and distance in aged cells required ERK and PI3K activation. By contrast, in control cells, basal migration was underpinned by PI3K activation, and facilitated by leucine or HMB supplementation, to migration levels seen in aged cells. These data suggest that replicatively aged myoblasts are not anabolically resistant per se, but are capable of efficient repair, underpinned by altered signaling pathways, compared with unaged control myoblasts
The Complex Dynamics of Wishful Thinking The Critical Positivity Ratio
We examine critically the claims made by Fredrickson and Losada (2005) concerning the construct known as the “positivity ratio.” We find no theoretical or empirical justification for the use of differential equations drawn from fluid dynamics, a subfield of physics, to describe changes in human emotions over time; furthermore, we demonstrate that the purported application of these equations contains numerous fundamental conceptual and mathematical errors. The lack of relevance of these equations and their incorrect application lead us to conclude that Fredrickson and Losada’s claim to have demonstrated the existence of a critical minimum positivity ratio of 2.9013 is entirely unfounded. More generally, we urge future researchers to exercise caution in the use of advanced mathematical tools, such as nonlinear dynamics, and in particular to verify that the elementary conditions for their valid application have been met
Solar cycle variation in solar f-mode frequencies and radius
Using data from the Global Oscillation Network Group (GONG) covering the
period from 1995 to 1998, we study the change with solar activity in solar
f-mode frequencies. The results are compared with similar changes detected from
the Michelson Doppler Imager (MDI) data. We find variations in f-mode
frequencies which are correlated with solar activity indices. If these changes
are due to variation in solar radius then the implications are that the solar
radius decreases by about 5 km from minimum to maximum activity.Comment: To appear in Solar Physic
Cognitive reserve and emotional stimuli in older individuals: level of education moderates the age-related positivity effect.
UNLABELLED: BACKGROUND/STUDY CONTEXT: A frequently observed age-related effect is a preference in older individuals for positive stimuli. The cognitive control model proposes that this positivity effect may be mediated by executive functions. We propose that cognitive reserve, operationally defined as years of education, which tempers cognitive decline and has been linked to executive functions, should also influence the age-related positivity effect, especially as age advances. METHODS: An emotional free recall test was administered to a group of 84 cognitively intact individuals aged 60 to 88, who varied in years of education. As part of a larger test battery, data were obtained on measures of executive functioning and depression. RESULTS: Multiple regression and moderation analyses were performed, controlling for general cognitive function, severity of depressive symptoms, and executive function. In our data, years of education appeared to moderate the effect of age on the positivity effect; age was negatively associated with recall of positive words in participants with fewer years of education, whereas a nonsignificant positive correlation was observed between age and positivity in participants with more education. CONCLUSION: Cognitive reserve appears to play a role in explaining individual differences in the positivity effect in healthy older individuals. Future studies should investigate whether cognitive reserve is also implicated in the ability to process a wide range of emotional stimuli and whether greater reserve is reflected in improved emotional regulation
Correlates of genetic monogamy in socially monogamous mammals: insights from Azara's owl monkeys
Understanding the evolution of mating systems, a central topic in evolutionary biology for more than 50 years, requires examining the genetic consequences of mating and the relationships between social systems and mating systems. Among pair-living mammals, where genetic monogamy is extremely rare, the extent of extra-group paternity rates has been associated withmale participation in infant care, strength of the pair bond and length of the breeding season. This study evaluated the relationship between two of those factors and the genetic mating system of socially monogamous mammals, testing predictions that male care and strength of pair bond would be negatively correlated with rates of extra-pair paternity (EPP). Autosomal microsatellite analyses provide evidence for genetic monogamy in a pair-living primate with bi-parental care, the Azara’s owl monkey (Aotus azarae). A phylogenetically corrected generalized least square analysis was used to relate male care and strength of the pair bond to their genetic mating system (i.e. proportions of EPP) in 15 socially monogamous mammalian species. The intensity of male care was correlated with EPP rates in mammals, while strength of pair bond failed to reach statistical significance. Our analyses showthat, once social monogamy has evolved, paternal care, and potentially also close bonds, may facilitate the evolution of genetic monogamy.German Science Foundation (HU 1746/2-1); Wenner-Gren Foundation; L.S.B. Leakey Foundation;National Geographic Society; National Science Foundation
(BCS-0621020, 1219368, and 1232349); the University of Pennsylvania Research Foundation; the Zoological Society of San Dieg
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