Visual Perception: Larger Is Faster

A recent study has shown that neurons in the inferior temporal cortex of the macaque monkey brain show earlier selectivity to global and large shapes than to local and small ones, which may underlie the faster behavioral responses to global aspects of a scene.     

Finding and Mapping New Genes Faster than Ever: Revisited

This article recounts some of the early days of the Human Genome Project, covering the important and sometimes controversial role that complementary DNA-based approaches played in the discovery and mapping of the majority of human genes. It also describes my involvement in this effort and my lab''s development of methods for rapid sequence identification and mapping of human genes.     

Bird communication: two voices are better than one

How do emperor penguins find their mates on a featureless ice flow, packed at densities of ten animals per square meter? A recent study has revealed how use of their 'two-voice' calls enables emperor penguins to locate their mates and chicks under some of nature's most extreme conditions.     

Visual perception: more than meets the eye

A recent study shows that objects changing in colour, luminance, size or shape appear to stop changing when they move. These and other compelling illusions provide tantalizing clues about the mechanisms and limitations of object analysis.     

The Impact of Accelerating Faster than Exponential Population Growth on Genetic Variation

Current human sequencing projects observe an abundance of extremely rare genetic variation, suggesting recent acceleration of population growth. To better understand the impact of such accelerating growth on the quantity and nature of genetic variation, we present a new class of models capable of incorporating faster than exponential growth in a coalescent framework. Our work shows that such accelerated growth affects only the population size in the recent past and thus large samples are required to detect the models’ effects on patterns of variation. When we compare models with fixed initial growth rate, models with accelerating growth achieve very large current population sizes and large samples from these populations contain more variation than samples from populations with constant growth. This increase is driven almost entirely by an increase in singleton variation. Moreover, linkage disequilibrium decays faster in populations with accelerating growth. When we instead condition on current population size, models with accelerating growth result in less overall variation and slower linkage disequilibrium decay compared to models with exponential growth. We also find that pairwise linkage disequilibrium of very rare variants contains information about growth rates in the recent past. Finally, we demonstrate that models of accelerating growth may substantially change estimates of present-day effective population sizes and growth times.     

Messages Do Diffuse Faster than Messengers: Reconciling Disparate Estimates of the Morphogen Bicoid Diffusion Coefficient

The gradient of Bicoid (Bcd) is key for the establishment of the anterior-posterior axis in Drosophila embryos. The gradient properties are compatible with the SDD model in which Bcd is synthesized at the anterior pole and then diffuses into the embryo and is degraded with a characteristic time. Within this model, the Bcd diffusion coefficient is critical to set the timescale of gradient formation. This coefficient has been measured using two optical techniques, Fluorescence Recovery After Photobleaching (FRAP) and Fluorescence Correlation Spectroscopy (FCS), obtaining estimates in which the FCS value is an order of magnitude larger than the FRAP one. This discrepancy raises the following questions: which estimate is "correct''''; what is the reason for the disparity; and can the SDD model explain Bcd gradient formation within the experimentally observed times? In this paper, we use a simple biophysical model in which Bcd diffuses and interacts with binding sites to show that both the FRAP and the FCS estimates may be correct and compatible with the observed timescale of gradient formation. The discrepancy arises from the fact that FCS and FRAP report on different effective (concentration dependent) diffusion coefficients, one of which describes the spreading rate of the individual Bcd molecules (the messengers) and the other one that of their concentration (the message). The latter is the one that is more relevant for the gradient establishment and is compatible with its formation within the experimentally observed times.     

Faster onset of action with topical levocabastine than with oral cetirizine

This international multicentre, open-label, parallel-group trial was undertaken to compare the therapeutic efficacy and tolerability of topical levocabastine and oral cetirizine in patients with perennial allergic rhinoconjunctivitis, with particular reference to the comparative onset of action of the two drugs. A total of 207 patients were randomized to receive either levocabastine nasal spray (0.5 mg/ml, two sprays in each nostril twice daily) plus levocabastine eye drops as required (0.5 mg/ml, one drop in each eye twice daily p.r.n.) or cetirizine orally (10 mg once daily) with a treatment duration of 2 weeks. Onset of action was found to be significantly more rapid with levocabastine than with cetirizine for both nasal and ocular symptoms (p < 0.001). Within 15 min of study drug administration, 36% of levocabastine-treated patients reported relief from nasal symptoms and 32% relief from ocular symptoms compared with 10% and 17% of patients on cetirizine, respectively. At 1 h, the percentages of patients reporting relief were 76% and 38% for nasal symptoms, and 81% and 48% for ocular symptoms in the levocabastine and cetirizine treatment groups, respectively. At 8 h there were no differences between the two treatments. Overall therapeutic efficacy was found to be comparable in the two treatment groups over the 2-week study period with no significant intergroup differences in symptom severity or global therapeutic efficacy. Both drugs were well tolerated with no significant differences in the incidence or type of adverse reactions between the two groups. In conclusion, levocabastine eye drops and nasal spray are as effective and well tolerated as oral cetirizine for the treatment of perennial allergic rhinoconjunctivitis with the advantage of a significantly faster onset of action for both nasal and ocular symptoms.     

Transgenic Animal Technology: Everything You Always Wanted to Know about Transgenics

Transgenic Research -     

Faster heme loss from hemoglobin E than HbS,in acidic pH: Effect of aminophospholipids

We report studies on loss of heme at or below pH 3.0 from two clinically important hemoglobin variants, HbE and HbS, in the presence and absence of phopholipid membranes. The kinetics of heme loss has been studied at pH 3.0 to simulate the same at a faster rate than at physiological pH, for spectroscopic investigation. Results obtained from the study clearly establish the probable fate of the lost heme to partition into the phospholipid bilayer independent of the pH range. This is also of particular importance to membranes containing the aminophospholipid and cholesterol which are predominantly localized in the inner leaflet of erythrocytes. Absorption measurements indicated such loss of heme when the Soret peak at 415 nm blue-shifted to 380 nm at pH 3.0. The extent of this blue shift decreased from 35 nm to ~15 nm in the presence of small unilammelar vesicles of both dimyristoyl- and dioleoyl-based phosphatidylcholine and phosphatidylethanolamine, indicating partitioning of the released heme in the membrane bilayer. The kinetics of heme loss was faster from HbE than HbA and HbS, obeying first-order reaction kinetics. Released heme could be involved in the premature destruction of erythrocytes in hemoglobin disorders.     

Own-Race Faces Capture Attention Faster than Other-Race Faces: Evidence from Response Time and the N2pc

Studies have shown that people are better at recognizing human faces from their own-race than from other-races, an effect often termed the Own-Race Advantage. The current study investigates whether there is an Own-Race Advantage in attention and its neural correlates. Participants were asked to search for a human face among animal faces. Experiment 1 showed a classic Own-Race Advantage in response time both for Chinese and Black South African participants. Using event-related potentials (ERPs), Experiment 2 showed a similar Own-Race Advantage in response time for both upright faces and inverted faces. Moreover, the latency of N2pc for own-race faces was earlier than that for other-race faces. These results suggested that own-race faces capture attention more efficiently than other-race faces.     

The Time-Course of Hatching Enzyme Secretion in the Sea Urchin Strongylocentrotus purpuratus

By two independent methods, we have determined approximately the time-course of hatching enzyme secretion in the sea urchin Strongylocentrotus purpuratus . A quick-kill method indicates that a significant fraction of the enzyme is secreted between 90% and 97% of the fertilization-hatching interval. A direct assay method indicates that the remainder of the enzyme is secreted on either side of the 90–97%window. The entire period of secretion spans from 75% to 100% or more of the fertilization-hatching interval. For embryos raised at 15°C this translates to an interval of 4.8 or more hr.     

Faster mass spectrometry-based protein inference: junction trees are more efficient than sampling and marginalization by enumeration

The problem of identifying the proteins in a complex mixture using tandem mass spectrometry can be framed as an inference problem on a graph that connects peptides to proteins. Several existing protein identification methods make use of statistical inference methods for graphical models, including expectation maximization, Markov chain Monte Carlo, and full marginalization coupled with approximation heuristics. We show that, for this problem, the majority of the cost of inference usually comes from a few highly connected subgraphs. Furthermore, we evaluate three different statistical inference methods using a common graphical model, and we demonstrate that junction tree inference substantially improves rates of convergence compared to existing methods. The python code used for this paper is available at http://noble.gs.washington.edu/proj/fido.     

Beyond Shape: How You Learn about Objects Affects How They Are Represented in Visual Cortex

Background

Experience can alter how objects are represented in the visual cortex. But experience can take different forms. It is unknown whether the kind of visual experience systematically alters the nature of visual cortical object representations.

Methodology/Principal Findings

We take advantage of different training regimens found to produce qualitatively different types of perceptual expertise behaviorally in order to contrast the neural changes that follow different kinds of visual experience with the same objects. Two groups of participants went through training regimens that required either subordinate-level individuation or basic-level categorization of a set of novel, artificial objects, called “Ziggerins”. fMRI activity of a region in the right fusiform gyrus increased after individuation training and was correlated with the magnitude of configural processing of the Ziggerins observed behaviorally. In contrast, categorization training caused distributed changes, with increased activity in the medial portion of the ventral occipito-temporal cortex relative to more lateral areas.

Conclusions/Significance

Our results demonstrate that the kind of experience with a category of objects can systematically influence how those objects are represented in visual cortex. The demands of prior learning experience therefore appear to be one factor determining the organization of activity patterns in visual cortex.     

一方羽翼的天空——观鸟之趣

观鸟是人们了解自然,感受自然,与自然融为一体的休闲娱乐活动。有点像狩猎,搜寻、辨认、刺激与收获,只不过观鸟人扳动的是望远镜的调焦旋钮,而不是猎枪上的扳机;收获的是身心的愉悦,而不是用金钱衡量的物质利益,观鸟是一种认识自然的自我生态教育。 生态旅游越来越受到人们的青睐,而观鸟旅游做为生态旅游的一种具体形式,正逐渐成为时尚。我在从事赛罕乌拉生物圈保护区的鸟类研究过程中,有意地进行了一些尝试和思考,从观鸟人     

The Scalpel and the Butterfly: The Conflict between Animal Research and Animal Protection Deborah Rudacille

ABSTRACT

Although there is a substantial body of research on inter-human empathy and inter-animal empathy, there is a dearth of research comparing humans' empathic reactions to humans and animals. To address this issue, three experiments were conducted in which participants read a scenario about a human or animal abuse victim in need of medical attention, and indicated the degree of empathy they had on an emotional response scale. In Experiment 1, women had significantly more empathy for animals than for humans, whereas men tended to express more empathy for humans than for animals. In Experiment 2, adult women expressed the same degree of empathy for a child as for a puppy. Similarly, in Experiment 3, adult men and women expressed the same degree of empathy for a baby as for a puppy. Overall, results indicated that people feel at least as much empathy for animals as for humans. We suggest that an animal target elicits a great deal of empathy partly because it is perceived as not being responsible for having caused the need situation. Future research will show whether empathy for animals translates to prosocial behavior toward them as well.     

Increased Mortality Exposure within the Family Rather than Individual Mortality Experiences Triggers Faster Life-History Strategies in Historic Human Populations

Life History Theory predicts that extrinsic mortality risk is one of the most important factors shaping (human) life histories. Evidence from contemporary populations suggests that individuals confronted with high mortality environments show characteristic traits of fast life-history strategies: they marry and reproduce earlier, have shorter birth intervals and invest less in their offspring. However, little is known of the impact of mortality experiences on the speed of life histories in historical human populations with generally higher mortality risk, and on male life histories in particular. Furthermore, it remains unknown whether individual-level mortality experiences within the family have a greater effect on life-history decisions or family membership explains life-history variation.In a comparative approach using event history analyses, we study the impact of family versus individual-level effects of mortality exposure on two central life-history parameters, ages at first marriage and first birth, in three historical human populations (Germany, Finland, Canada). Mortality experience is measured as the confrontation with sibling deaths within the natal family up to an individual''s age of 15.Results show that the speed of life histories is not adjusted according to individual-level mortality experiences but is due to family-level effects. The general finding of lower ages at marriage/reproduction after exposure to higher mortality in the family holds for both females and males. This study provides evidence for the importance of the family environment for reproductive timing while individual-level mortality experiences seem to play only a minor role in reproductive life history decisions in humans.