Reasons for female neonaticide in India

Invited commentary on ‘Neonaticide in India and the stigma of female gender: report of two cases’, Mishra et al

Hadronic Gamma Rays from Supernova Remnants

A gas cloud near a supernova remnant (SNR) provides a target for pp-collisions leading to subsequent gamma-ray emission through neutral pion decay. The assumption of a power-law ambient spectrum of accelerated particles with index near -2 is usually built into models predicting the spectra of very-high energy (VHE) gamma-ray emission from SNRs. However, if the gas cloud is located at some distance from the SNR shock, this assumption is not necessarily correct. In this case, the particles which interact with the cloud are those leaking from the shock and their spectrum is approximately monoenergetic with the injection energy gradually decreasing as the SNR ages. In the GLAST energy range the gamma-ray spectrum resulting from particle interactions with the gas cloud will be flatter than expected, with the cutoff defined by the pion momentum distribution in the laboratory frame. We evaluate the flux of particles escaping from a SNR shock and apply the results to the VHE diffuse emission detected by the HESS at the Galactic centre.Comment: 4 pages, 3 figures. Contribution to the 30th ICRC, Merida, Mexico, 2007 (final version

The Use of Online Panel Data in Management Research: A Review and Recommendations

Management scholars have long depended on convenience samples to conduct research involving human participants. However, the past decade has seen an emergence of a new convenience sample: online panels and online panel participants. The data these participants provide—online panel data (OPD)—has been embraced by many management scholars owing to the numerous benefits it provides over “traditional” convenience samples. Despite those advantages, OPD has not been warmly received by all. Currently, there is a divide in the field over the appropriateness of OPD in management scholarship. Our review takes aim at the divide with the goal of providing a common understanding of OPD and its utility and providing recommendations regarding when and how to use OPD and how and where to publish it. To accomplish these goals, we inventoried and reviewed OPD use across 13 management journals spanning 2006 to 2017. Our search resulted in 804 OPD-based studies across 439 articles. Notably, our search also identified 26 online panel platforms (“brokers”) used to connect researchers with online panel participants. Importantly, we offer specific guidance to authors, reviewers, and editors, having implications for both micro and macro management scholars

Noxious and other bad weeds of Iowa

Within the past 15 years weeds have come to be recognized as the cause of one of the most important losses suffered by American farmers. Experiment station and extension workers, farmers, weed commissioners, insurance companies and farm credit agencies, chambers of commerce and others either directly or indirectly dependent on agriculture have become aroused by the menace of an increased dissemination of noxious weeds. In Iowa weeds cause a loss of many millions of dollars annually. They crowd out desirable crops, rob them of plant food and moisture, act as hosts for insects and disease-producing organisms of crops, poison or injure livestock, depreciate land values and cause extra labor in cultivation; thus they increase the cost of food production

The relative contributions of cereal production, imports, and aid to somali food security

Somalia is among the poorest countries on the planet. Since the fall of Siad Barre’s regime in 1991, the country has been in a near-constant state of food insecurity and suffered two officially declared famines. In order to address the issue of food insecurity in Somalia, a greater understanding of each of the components that contribute to the Somali food supply is merited. Cereal crops make up a third to half of the Somali diet by calories and are among the most important food crops produced by the country. This study investigated the historic trends in domestic cereal production, cereal imports, and food aid (reported in cereal equivalents) in Somalia by exploring secondary data publicly available from the Food and Agriculture Organization (FAO) of the United Nations, and the World Food Programme. These data were related to World Bank population data in Microsoft Excel and average per capita production, import, and aid figures were calculated. Median changes over time and their associated interquartile ranges were reported. The data demonstrated that Somali cereal production levels have not improved since the 1960’s, and since that time, they have been characterized by an extreme amount of year-to-year volatility. Moreover, maize and sorghum are the only meaningful fractions of Somalia’s domestic cereal production, and recent total production of each crop is well below the levels observed in the 1980’s. When combined, per capita production of maize and sorghum has decreased precipitously over time (falling from a high of 91 kg per capita in 1972 to just 30 kg per capita in 2012). This is likely due to a combination of stagnant production and rapidly increasing Somali population (up over 350% since 1961). This has increased the importance of cereal imports and aid to Somalia and has made the country vulnerable to disruptions in international cereal markets and foreign government policies. Improving domestic cereal production in Somalia should be part of any future food security strategy for the country. Recent agricultural research in Somalia suggests that the implementation of simple agricultural best management practices can increase cereal production in the country.Keywords: Somalia, Population Growth, Cereal Production, Cereal Imports, Food AidAfr. J. Food Agric. Nutr. Dev. 2019; 19(3): 14587-1460

Broken symmetries and pattern formation in two-frequency forced Faraday waves

We exploit the presence of approximate (broken) symmetries to obtain general scaling laws governing the process of pattern formation in weakly damped Faraday waves. Specifically, we consider a two-frequency forcing function and trace the effects of time translation, time reversal and Hamiltonian structure for three illustrative examples: hexagons, two-mode superlattices, and two-mode rhomboids. By means of explicit parameter symmetries, we show how the size of various three-wave resonant interactions depends on the frequency ratio m:n and on the relative temporal phase of the two driving terms. These symmetry-based predictions are verified for numerically calculated coefficients, and help explain the results of recent experiments.Comment: 4 pages, 6 figure

Non-linear rheology of active particle suspensions: Insights from an analytical approach

We consider active suspensions in the isotropic phase subjected to a shear flow. Using a set of extended hydrodynamic equations we derive a variety of {\em analytical} expressions for rheological quantities such as shear viscosity and normal stress differences. In agreement to full-blown numerical calculations and experiments we find a shear thickening or -thinning behaviour depending on whether the particles are contractile or extensile. Moreover, our analytical approach predicts that the normal stress differences can change their sign in contrast to passive suspensions.Comment: 11 pages, 10 figures, appear in PR

Limits on τ lepton-flavor violating decays into three charged leptons

A search for the neutrinoless, lepton-flavor violating decay of the τ lepton into three charged leptons has been performed using an integrated luminosity of 468  fb^(-1) collected with the BABAR detector at the PEP-II collider. In all six decay modes considered, the numbers of events found in data are compatible with the background expectations. Upper limits on the branching fractions are set in the range (1.8–3.3)×10^(-8) at 90% confidence level