Looking away from faces: influence of high-level visual processes on saccade programming

Human faces capture attention more than other visual stimuli. Here we investigated whether such face-specific biases rely on automatic (involuntary) or voluntary orienting responses. To this end, we used an anti-saccade paradigm, which requires the ability to inhibit a reflexive automatic response and to generate a voluntary saccade in the opposite direction of the stimulus. To control for potential low-level confounds in the eye-movement data, we manipulated the high-level visual properties of the stimuli while normalizing their global low-level visual properties. Eye movements were recorded in 21 participants who performed either pro- or anti-saccades to a face, car, or noise pattern, randomly presented to the left or right of a fixation point. For each trial, a symbolic cue instructed the observer to generate either a pro-saccade or an anti-saccade. We report a significant increase in anti-saccade error rates for faces compared to cars and noise patterns, as well as faster pro-saccades to faces and cars in comparison to noise patterns. These results indicate that human faces induce stronger involuntary orienting responses than other visual objects, i.e., responses that are beyond the control of the observer. Importantly, this involuntary processing cannot be accounted for by global low-level visual factors

Microparasite species richness in rodents is higher at lower latitudes and is associated with reduced litter size

Parasite species loads are expected to be higher in the tropics and higher parasite species richness to have cumulative effects on host physiology or demography. Despite being regularly assumed or predicted, empirical evidence on specieslatitude patterns is scarce or contradictory and studies on the impacts of concomitant infections have mainly been done at host intra-specific level. Broad generalizations are then very hard, if not spurious. By focusing on rodent species and their non-eukaryotic microparasites (i.e. viruses and bacteria), we investigated, using a comparative approach, microparasite species richness across rodent species according to the latitude where they occur. We also explored the links between rodents' reproductive traits, latitude and microparasite species richness. We find for the first time in rodents that virus species richness increases towards tropical latitudes, and that rodent litter size seems to decrease when microparasite species richness increases independently from the latitude. These results support the hypotheses that rodent species in the tropics effectively harbour higher parasite species loads, at least in terms of species richness for viruses, and that parasite species richness influences rodent life-history traits. Although some other factors, such as seasonality, were not taken into account due the lack of data, our study stresses the idea that chronic microparasite infections may have detrimental effects on their rodent host reservoirs, notably by affecting litter size

Micro- and macroparasite species richness in birds:The role of host life history and ecology

Identifying the factors shaping variation in parasite diversity among host species is crucial to understand wildlife diseases. Although micro‐ and macroparasites may exert different selective pressures on their hosts, studies investigating the determinants of parasite species richness in animals have rarely considered this divide. Here, we investigated the role of host life history and ecology in explaining the species richness of helminths (macroparasites) and haemosporidians (microparasites) in birds world‐wide. We collated data from multiple global datasets on diverse bird traits (longevity, body mass, coloniality, migration distance/tendency, geographic range size and dietary and habitat breadths) and the species richness of their helminth and haemosporidian parasites. We tested predictors of helminth and haemosporidian parasite richness using phylogenetic generalized linear mixed models in a Bayesian framework. We found that, after controlling for research effort and host phylogeny, the richness of helminths, but not of haemosporidians, increased with host longevity, range size, migration distance and dietary breadth. Overall, these correlates were also important across different helminth groups (acanthocephalans, cestodes, nematodes and trematodes), and two additional ones (body mass, coloniality) emerged as important for cestodes and acanthocephalans. We propose that long life spans may promote the diversity of helminth parasite assemblages over evolutionary time, thus resulting in richer helminth faunas. Similarly, longer‐distance migrations, larger ranges and broader dietary breadths are likely to lead to greater encounter rates and the accumulation of trophically transmitted helminths. In contrast, vector‐borne haemosporidians may be influenced more by factors related to vector ecology than by the host traits included in the analyses. The lack of strong associations between haemosporidian species richness and host characteristics emphasizes the need to find appropriate traits to model the distribution and diversity of parasites with different environmental preferences in order to anticipate disease emergence risks associated with global change

Strangeness S=−2S=-2 baryon-baryon interactions in relativistic chiral effective field theory

We study the strangeness $S=-2$ baryon-baryon interactions in relativistic chiral effective field theory at leading order. Among the 15 relevant low energy constants, eight of them are determined by fitting to the state of the art lattice QCD data of the HAL QCD Collaboration (with $m_\pi=146$ MeV), and the rest are either taken from the study of the $S=-1$ hyperon-nucleon systems, assuming strict SU(3) flavor symmetry, or temporarily set equal to zero. Using the so-obtained low energy constants, we extrapolate the results to the physical point, and show that they are consistent with the available experimental scattering data. Furthermore, we demonstrate that the $\Lambda\Lambda$ and $\Xi N$ phase shifts near the $\Xi N$ threshold are very sensitive to the lattice QCD data fitted, to the pion mass, and to isospin symmetry breaking effects. As a result, any conclusion drawn from lattice QCD data at unphysical pion masses (even close to the physical point) should be taken with caution. Our results at the physical point, similar to the lattice QCD data, show that a resonance/quasi-bound state may appear in the $I=0$ $\Lambda\Lambda$/$\Xi N$ channel.Comment: 20 pages, 8 figure

Assessing varietal resistances to control common wheat bunt under organic cereal production and soft wheat, in particular

Common wheat bunt (caused by the fungus Tilletia caries or Tilletia foetida) is a disease whose incidence is clearly on the rise in organic farming, jeopardising the balance of the French organic cereal sector. Control methods adapted to organic farming must be found, especially since we know that no seed treatment is 100% effective. The use of varietal resistance appears particularly promising for limiting the spread of the disease. Since 2000, an experiment whose purpose is to assess the resistance of soft wheat varieties to Tilletia caries is conducted each year by the French plant institute, ARVALIS. These experiments make it possible to identify the existence of a wide behavioural variability with respect to this pathogen among the different varieties grown in France. However, no variety corresponding to the specific criteria imposed by organic agriculture has yet to show adequate levels of resistance. At the same time, a European testing network revealed a strong genotype X environment interaction, emphasizing the necessity of consolidating these initial observations by increasing the number of test sites and by identifying virulence genes present in France as well as resistance genes present in the different varieties

The H-Index as a Quantitative Indicator of the Relative Impact of Human Diseases

Assessment of the relative impact of diseases and pathogens is important for agencies and other organizations charged with providing disease surveillance, management and control. It also helps funders of disease-related research to identify the most important areas for investment. Decisions as to which pathogens or diseases to target are often made using complex risk assessment approaches; however, these usually involve evaluating a large number of hazards as it is rarely feasible to conduct an in-depth appraisal of each. Here we propose the use of the H-index (or Hirsch index) as an alternative rapid, repeatable and objective means of assessing pathogen impact. H-index scores for 1,414 human pathogens were obtained from the Institute for Scientific Information's Web of Science (WOS) in July/August 2010. Scores were compared for zoonotic/non-zoonotic, and emerging/non-emerging pathogens, and across taxonomic groups. H-indices for a subset of pathogens were compared with Disability Adjusted Life Year (DALY) estimates for the diseases they cause. H-indices ranged from 0 to 456, with a median of 11. Emerging pathogens had higher H-indices than non-emerging pathogens. Zoonotic pathogens tended to have higher H-indices than human-only pathogens, although the opposite was observed for viruses. There was a significant correlation between the DALY of a disease and the H-index of the pathogen(s) that cause it. Therefore, scientific interest, as measured by the H-index, appears to be a reflection of the true impact of pathogens. The H-index method can be utilized to set up an objective, repeatable and readily automated system for assessing pathogen or disease impact