The impact of climatic variation on the opportunity for sexual selection

Many studies have demonstrated influences of climatic variation on a variety of ecological processes, however, its impact on the potent evolutionary force of sexual selection has largely been ignored. The intensity of sexual selection is a fundamental parameter in animal populations, which depends upon the degree of polygamy and will probably be influenced by the impact of local climatic variation upon 'environmental potential for polygamy'. Here, we provide evidence of a direct effect of local climatic variation on the intensity of sexual selection, by showing a clear correlation between local weather conditions and inter-annual changes in the degree of polygamy in a long-term study of colonially breeding grey seals (Halichoerus grypus). Our results show that changes in local weather conditions alter the annual proportion of males contributing to the effective population size (Ne) by up to 61%. Consequently, over the 'lifetime' of a cohort, a broader range of individuals will contribute genetically to the next generation if local weather conditions are variable. In the context of predicted future changes in climatic variation, these findings have broad implications for population genetics of socially structured animal systems through the major influence that the degree of polygamy has upon Ne.     

On the opportunity cost of the photosynthate invested in stem elongation reactions mediated by phytochrome

Summary Seedlings of shade-intolerant species react to alterations of the light climate caused by their neighbors with morphological changes that may influence the pattern of resource acquisition and utilization at the whole-canopy level. One such change, the increased stem elongation rate that is triggered by low red (R, 660 nm) to far-red (FR, 730 nm) ratios (R:FR) in dense canopies, might reduce the amount of assimilates available for leaf area expansion or root growth, and in that way affect resource capture by the canopy. We have tested this hypothesis by comparing the growth of both isolated individuals and canopies of the weed Amaranthus quitensis under conditions differing only in the spectral distribution of the incident light. When canopies received the full spectrum of sunlight, the stems were a large proportion (40–57%) of total biomass. Filtering the FR waveband (and hence raising the R:FR ratio to eliminate the neighbors' proximity-signal) resulted in shorter canopies with lighter stems. However, the growth of leaves and roots was not promoted by this treatment, indicating that the opportunity cost of the assimilates invested in the stems was nil or very small. Filtering the FR had no effect on biomass accumulation when plants were grown as isolated individuals. The higher growth of the canopics under full spectrum could be due to a higher light interception or to a higher efficiency of light conversion into biomass. The first possibility is weakened by the observation that filtering the FR had no effect on the dynamics of soil covering by the crops. The second is indirectly strengthened by results of an experiment with isolated plants showing that stem elongation, stem growth, and total plant biomass can be increased by reducing the flux of R light received by the stems without affecting the light climate of the leaves. Further work is needed to distinguish between these two possibilities; whatever the cause, our results show that the elongation responses to decreased R:FR may lead to a net increase in canopy productivity, and do not necessarily have a negative impact on the growth of resource-harvesting organs.     

Impact beyond the impact factor

The journal impact factor is an annually calculated number for each scientific journal, based on the average number of times its articles published in the two preceding years have been cited. It was originally devised as a tool for librarians and publishers to provide information about the citation performance of a journal as a whole, but over the last few decades it has increasingly been used to assess the quality of specific articles and the research performance of individual investigators, institutions, and countries. In addition to this clear abuse of the journal impact factor, several conceptual and technical issues limit its usability as a measure of journal reputation, especially when journals are compared across different fields. An author’s decision regarding the suitability of a scholarly journal for publication should, therefore, be based on the impact that this journal makes in the field of research, rather than on the journal impact factor.     

Obesity impact on the attentional cost for controlling posture

Background

This study investigated the effects of obesity on attentional resources allocated to postural control in seating and unipedal standing.

Methods

Ten non obese adults (BMI = 22.4±1.3, age = 42.4±15.1) and 10 obese adult patients (BMI = 35.2±2.8, age = 46.2±19.6) maintained postural stability on a force platform in two postural tasks (seated and unipedal). The two postural tasks were performed (1) alone and (2) in a dual-task paradigm in combination with an auditory reaction time task (RT). Performing the RT task together with the postural one was supposed to require some attentional resources that allowed estimating the attentional cost of postural control. 4 trials were performed in each condition for a total of 16 trials.

Findings

(1) Whereas seated non obese and obese patients exhibited similar centre of foot pressure oscillations (CoP), in the unipedal stance only obese patients strongly increased their CoP sway in comparison to controls. (2) Whatever the postural task, the additional RT task did not affect postural stability. (3) Seated, RT did not differ between the two groups. (4) RT strongly increased between the two postural conditions in the obese patients only, suggesting that body schema and the use of internal models was altered with obesity.

Interpretation

Obese patients needed more attentional resources to control postural stability during unipedal stance than non obese participants. This was not the case in a more simple posture such as seating. To reduce the risk of fall as indicated by the critical values of CoP displacement, obese patients must dedicate a strong large part of their attentional resources to postural control, to the detriment of non-postural events. Obese patients were not able to easily perform multitasking as healthy adults do, reflecting weakened psycho-motor abilities.     

Microbiological high throughput screening: an opportunity for the lead discovery process

Microbial HTS has been implemented at Rh?ne-Poulenc Rorer through the development of a dedicated robotic platform. This robot (Turbo) has been designed with the aim of fully integrating microbial HTS into the lead discovery processes. Innovative solutions have been found to reach high throughput as well as flexibility. This opens up new prospects for solid-phase microbial screening, taking advantage of the easy implementation and the very low costs of such screens. The different types of microbial screens done in our laboratory, as well as the throughputs and outputs obtained, are described. Some of the specific aspects of microbial HTS, as compared to biochemical and cell-based assays, are also discussed.     

Comparison of environmental impact and external cost assessment methods

Background, aim, and scope  

Impact assessment can be completed with the help of Life Cycle Impact Assessment (LCIA) as a part of Life Cycle Assessment (LCA) and External Cost Assessment methods. These methods help, for project and product classifications, to protect human health and the environment. Comparison of different impact assessment methods along parallel evaluations of real air pollution case studies helps to detect similarities and dependencies between them. The comparison helps and supports the work in both areas by mutually exploiting the merits of both methods. On the other hand, the detected similarities and dependencies also support the accuracy of the assessment work.     

Sometimes the impact factor outshines the H index

Human immunodeficiency virus type 2 (HIV-2) emerged following cross-species transmission of simian immunodeficiency virus (SIV) from sooty mangabeys to humans several decades ago. The epidemic groups of HIV-2 have been established in the human population for at least 50 years. However, it is likely that new divergent SIVs can infect humans and lead to new outbreaks. We report the isolation of a new strain of HIV-2, HIV2-NWK08F, from an immunodeficient Sierra Leone immigrant. Health care providers in Sierra Leone and elsewhere need to be alerted that a subtype of HIV-2, which is not detected by PCR for epidemic HIV-2 strains, exists and can lead to immunosuppression.     

A recipe for high impact

Our analysis highlights common statistical features of high-impact articles; we also show how information flows among various publication types.     

Unusually high evolutionary rate of the elongation factor 1 alpha genes from the Ciliophora and its impact on the phylogeny of eukaryotes

The elongation factor 1 alpha (EF-1 alpha) has become widely employed as a phylogenetic marker for studying eukaryotic evolution. However, a disturbing problem, the artifactual polyphyly of ciliates, is always observed. It has been suggested that the addition of new sequences will help to circumvent this problem. Thus, we have determined 15 new ciliate EF-1 alpha sequences, providing for a more comprehensive taxonomic sampling of this phylum. These sequences have been analyzed together with a representation of eukaryotic sequences using distance-, parsimony-, and likelihood-based phylogenetic methods. Such analyses again failed to recover the monophyly of Ciliophora. A study of the substitution rate showed that ciliate EF-1 alpha genes exhibit a high evolutionary rate, produced in part by an increased number of variable positions. This acceleration could be related to alterations of the accessory functions acquired by this protein, likely to those involving interactions with the cytoskeleton, which is very modified in the Ciliophora. The high evolutionary rate of these sequences leads to an artificial basal emergence of some ciliates in the eukaryotic tree by effecting a long-branch attraction artifact that produces an asymmetric topology for the basal region of the tree. The use of a maximum-likelihood phylogenetic method (which is less sensitive to long-branch attraction) and the addition of sequences to break long branches allow retrieval of more symmetric topologies, which suggests that the asymmetric part of the tree is most likely artifactual. Therefore, the sole reliable part of the tree appears to correspond to the apical symmetric region. These kinds of observations suggest that the general eukaryotic evolution might have consisted of a massive radiation followed by an increase in the evolutionary rates of certain groups that emerge artificially as early branches in the asymmetric base of the tree. Ciliates in the case of the EF-1 alpha genes would offer clear evidence for this hypothesis.     

The high cost of half-hearted breastfeeding promotion in Germany

The economic value of breastfeeding to the society at large is under researched and its importance as a preventive public health strategy is underestimated. What little research there is indicates that considerable savings would accrue from following the WHO/UNICEF advice to breastfeed exclusively for six months and continue breastfeeding along with complementary foods for two years or more. Despite relatively high breastfeeding initiation in Germany, neither exclusive breastfeeding nor breastfeeding duration come close to international recommendations. Breastfeeding is mostly regarded as a woman’s personal choice and the government has been slow to engage in breastfeeding promotion, support and research. Some structures in Germany do offer support for breastfeeding women – including the growing number of Baby Friendly Hospital Initiative (BFHI) certified hospitals and a comprehensive maternity leave policy. However, the costs of breastfeeding are mostly borne by the mothers and those for breastfeeding training mostly by the individual health care workers or hospital, while the health insurance companies and society-at-large are profiting from the financial savings from exclusive and long-term breastfeeding. Factors which might improve breastfeeding rates and duration in this country include broad expansion of and financial support for both BFHI hospitals as well as training for the health care personnel who support the mother-infant dyad during the breastfeeding period.