Collective Gradient Sensing in Fish Schools

Throughout the animal kingdom, animals frequently benefit from living in groups. Models of collective behaviour show that simple local interactions are sufficient to generate group morphologies found in nature (swarms, flocks and mills). However, individuals also interact with the complex noisy environment in which they live. In this work, we experimentally investigate the group performance in navigating a noisy light gradient of two unrelated freshwater species: golden shiners (Notemigonuscrysoleucas) and rummy nose tetra (Hemigrammus bleheri). We find that tetras outperform shiners due to their innate individual ability to sense the environmental gradient. Using numerical simulations, we examine how group performance depends on the relative weight of social and environmental information. Our results highlight the importance of balancing of social and environmental information to promote optimal group morphologies and performance

Illness reporting and demand for medical care in rural Burkina Faso

This is the post-print version of the final paper published in Social Science & Medicine. The published article is available from the link below. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. Copyright @ 2010 Elsevier B.V.The issue of illness reporting in modelling demand for health care in low- and middle-income countries can be handled according to either of two conceptually-different constructs: (a) considering illness reporting behaviour as endogenous to demand; or (b) considering demand itself as the outcome of a sample selection phenomenon. In this paper, we take the second viewpoint and estimate the demand for medical care with an estimator that uses Heckman-type. Empirical estimates based on household survey data from rural Burkina Faso suggest that there are some implications of illness reporting behaviour for modelling the demand for medical care.German Science Foundatio

H I Structure and Kinematics of the Interstellar Medium in the LITTLE THINGS Galaxies

We present a catalog of the neutral atomic hydrogen structures (H I holes) and the analysis of their properties in nearby (≤ 10.3 Mpc) gas-rich dwarf galaxies of the LITTLE THINGS (Local Irregulars That Trace Luminosity Extremes, The H I Nearby Galaxy Survey) group. We used high sensitivity (≤ 1.1 mJy beam-1 channel-1), high velocity resolution (1.3 km s-1 to 2.6 km s-1) and high linear resolution (average ~110 pc; angular resolution ~6”) H I data of 37 dwarf irregulars and four blue compact dwarf galaxies. We cataloged H I holes in the entire sample and studied the of the properties of holes. We also investigated the effect of H I porosity on star formation, and the correlation of the star formation rate (SFR) calculated from H I holes with standard star formation tracers Hα and FUV. We detected 306 H I holes in LITTLE THINGS galaxies. We confirmed 22 kpc-sized holes, the largest and the smallest hole diameters are about 2.3 kpc and 38 pc (resolution limit) respectively. The expansion velocities of the holes range from 5 km s-1 (upper limit) to 30 km s-1, and the rotational velocities range from 6 km s-1 to 77 km s-1. The H I disk radii of the galaxies range from about 0.5 kpc to 6.7 kpc. The kinetic ages of the holes range from about 1 to 127 Myr, and the estimated scale heights are varying from 61 pc to 653 pc. The percentage distribution of the holes outside and inside the V-band break radius is nearly uniform, 49% and 51% respectively. In LITTLE THINGS galaxies, we found no obvious correlation between the surface and volume porosities, and SFR. However, two highest and two lowest porosity galaxies have no star formation at present. The holes are consistent with the SFR estimated from the energy required to create a hole and the star formation rates measured from Hα and FUV, indicating that the holes are consistent with a star formation origin

Evaluation of Colloidal Stability and Ecotoxicity of Metal-based Nanoparticles in the Aquatic and Terrestrial Systems

Intrinsic to the many nano-enabled products are atomic-size multifunctional engineered nanomaterials, which upon release contaminate the environments, raising considerable health and safety concerns. This Ph.D. dissertation is designed to investigate (i) whether metals or oxide nanoparticles are more toxic than ions, and if MetPLATETM bioassay is applicable as a rapid nanotoxicity screening tool; (ii) how variable water chemistry (dissolved organic carbon (DOC), pH, and hardness) and organic compounds (cysteine, humic acid, and trolox) modulate colloidal stability, ion release, and aquatic toxicity of silver nanoparticles (AgNP); and (iii) the developmental responses of crop plants exposed to Ag- or ZnO- (zinc oxide) nanoparticles. Results suggest that the MetPLATEcan be considered a high-throughput screening tool for rapid nanotoxicity evaluation. Detectable changes in the colloidal diameter, surface charge, and plasmonic resonance revealed modulating effects of variable water chemistry and organic ligands on the particle stability, dissolution, and toxicity of AgNPs against Escherichia coli or Daphnia magna. Silver dissolution increased as a function of DOC concentrations but decreased with increasing hardness, pH, cysteine, or trolox levels. Notably, the dissociated Ag+ was inadequate to explain AgNP toxicity, and that the combined effect of AgNPs and dissolved Ag+ under each ligand treatment was lower than of AgNO3. Significant attenuation by trolox signifies an oxidative stress-mediated AgNP toxicity; its inability to attenuate AgNO3 toxicity, however, negates oxidative stress as Ag+ toxicity mechanism, and that cysteine could effectively quench free Ag+ to alleviate AgNO3 toxicity in D. magna. Surprisingly, DOC-AgNPs complex that apparently formed at higher DOC levels might have led daphnids filter-feed on aggregates, potentially elevating internal dose, and thus higher mortality. Maize root anatomy showed differential alterations upon exposure to AgNPs, ZnONPs, or their ions. Overall, various metal-based nanoparticles revealed lower toxicity than their ions against multiple organisms. This study showed that particle size, surface properties, and ion release kinetics of AgNPs modify following release into aquatic environment, suggesting potential implications to ecosystem health and functions, and that caution be applied when extending one species toxicity results to another because obvious differences in organism biology—supporting species sensitivity paradigm—can significantly alter nanoparticle or ionic toxicity

How much improvement in mental health can be expected when people stop smoking? Findings from a national survey

Background and aims: There is evidence that mental health improves when smokers stop. This study aimed to assess in a nationally representative sample how far anxiety and depression in long-term ex-smokers can be expected eventually to reach levels found in those who have never smoked. Methods: Data from the Smoking Toolkit Study (STS) were used. The STS involves monthly household surveys of representative samples of the adult population of England. Anxiety and depression were compared using an item from the EQ5-D in respondents aged 40+ years where were either current smokers, never smokers, or had stopped for at least a year, adjusting statistically for age, gender and social grade. Results: The prevalence of anxiety or depression was 10.0% (95% CI 9.1-10.9) in never smokers, 18.3% (95% CI 16.0-20.6) in current smokers, and 11.3% (95% CI 9.6-13.0) in long-term ex-smokers. After adjusting for age, sex and social grade, long-term ex-smokers were similar to never smokers (OR=1.15, 95% CI=0.94-1.41). Current smokers had higher prevalence than never smokers (OR=1.69, 95% CI=1.39-2.04) and ex-smokers (OR=1.47, 95% CI=1.15-1.86). Conclusions: Prevalence of anxiety and depression in long-term ex-smokers appears to be similar to what is found in never smokers

Prevalence of Postpartum Family Planning Service Coverage in Selected Referral Facilities of Nepal

Introduction: Nepal Society of Obstetricians and Gynecologists jointly with the Nepalese government and with the support from the International Federation of Obstetrics and Gynecology has implemented an initiative to institutionalize postpartum family planning services in selected major referral facilities of Nepal to address the gap of low uptake of postpartum family planning in Nepal. The aim of the study is to find the prevalence of the service coverage of postpartum contraception in the selected facilities. Methods: A descriptive cross-sectional study was conducted in seven major referral facilities across Nepal. Data were collected from the hospital records of all women who delivered in these facilities between October 2018 and March 2019. Ethical approval for this study was obtained from Nepal Health Research Council. Data analysis was done with SPSS version 23. Results: Among the 29,072 deliveries from all the facilities, postpartum family planning counseling coverage was 27,301 (93.9%). The prevalence of uptake of Postpartum Intrauterine Device is 1581 (5.4%) and female sterilization is 1830 (6.3%). In total 11387 mothers (52.2%) had the intention to choose a postpartum family planning method. However, 36% of mothers neither used nor had the intention to choose a postpartum family planning method. Conclusions: The coverage of Postpartum Intrauterine Device counseling service coverage in Nepal is higher in 2018 as compared to 2016-2017 and in other countries implementing Postpartum Intrauterine Device initiatives. However, the prevalence of service coverage of immediate Postpartum Family Planning methods, mainly Postpartum Intrauterine Device in 2018 is lower in Nepal as compared to 2016-2017, and other countries implementing Postpartum Intrauterine Device initiative. More efforts are needed to encourage mothers delivering in the facilities to use the postpartum family planning method

Step-wedge cluster-randomised community-based trials: An application to the study of the impact of community health insurance

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.BACKGROUND: We describe a step-wedge cluster-randomised community-based trial which has been conducted since 2003 to accompany the implementation of a community health insurance (CHI) scheme in West Africa. The trial aims at overcoming the paucity of evidence-based information on the impact of CHI. Impact is defined in terms of changes in health service utilisation and household protection against the cost of illness. Our exclusive focus on the description and discussion of the methods is justified by the fact that the study relies on a methodology previously applied in the field of disease control, but never in the field of health financing. METHODS: First, we clarify how clusters were defined both in respect of statistical considerations and of local geographical and socio-cultural concerns. Second, we illustrate how households within clusters were sampled. Third, we expound the data collection process and the survey instruments. Finally, we outline the statistical tools to be applied to estimate the impact of CHI. CONCLUSION: We discuss all design choices both in relation to methodological considerations and to specific ethical and organisational concerns faced in the field. On the basis of the appraisal of our experience, we postulate that conducting relatively sophisticated trials (such as our step-wedge cluster-randomised community-based trial) aimed at generating sound public health evidence, is both feasible and valuable also in low income settings. Our work shows that if accurately designed in conjunction with local health authorities, such trials have the potential to generate sound scientific evidence and do not hinder, but at times even facilitate, the implementation of complex health interventions such as CHI

PCR Based Genotyping of Lulu Cattle of Nepal for A1, A2 Type Beta-caseins

Lulu is an indigenous breed of cattle (Bos taurus) found in high altitude regions of western Nepal. Population of Lulu cattle has been declining due to introgression with other exotic breeds to increase milk productivity. Here we aimed at finding potential approach for conserving Lulu cattle and its assets by studying the milk contents and investigating which variant of beta-casein protein is present in this breed. Beta caseins are an abundant protein in cow milk with A1 and A2 being the most common genetic variants of this protein. Consumption of A1 type of milk has numerous health-related complications whereas A2 type of milk has numerous human health promoting factors. We used restriction fragment length polymorphism (RFLP) for determining the A1 and A2 variant of beta casein in Lulu cattle. For performing DNA extraction, we collected (n = 18) blood samples of Lulu from Mustang and (n=17) Nepal Agriculture research council farm. The amplified fragments in 3% agarose at 251bp and 213bp respectively confirmed the presence of both A1 and A2 gene in Lulu; however, A2 was of greater abundance. Our study indicated that Lulu has A2 variant of beta-casein predominantly. The gene frequency of A1A1 is 0, A1A2 is 0.06 and A2A2 is 0.94. We further found that the allele frequency of A1 and A2 is 0.03 and 0.97 respectively. We designed special primer for sequencing CSN2 genes since A2 type beta casein gene was predominantly seen on Lulu. The sequencing result further supports our RFLP result as most of our samples have “C” nucleotide SNP in amplified CSN2 gene sequence. The Chi-square value of the current study is 0.04 which supports Hardy-Weinberg equilibrium inferring that Lulu cattle are still in the pure state, where there is no genetic introgression with the exotic breed for the sake of improvement of productivity