Mean lives of some astrophysically important excited levels in carbon, nitrogen and oxygen

A number of astrophysically important mean lives of levels in carbon, nitrogen and oxygen were measured with the beam-foil technique. New values are reported and compared with earlier theoretical and experimental values. Direct references to astrophysical applications are listed

The mean lives of some excited levels in nitrogen 1

Beam foil measurements of multiplet mean lives in nitrogen deca

Meta-learners for Estimating Heterogeneous Treatment Effects using Machine Learning

There is growing interest in estimating and analyzing heterogeneous treatment effects in experimental and observational studies. We describe a number of meta-algorithms that can take advantage of any supervised learning or regression method in machine learning and statistics to estimate the Conditional Average Treatment Effect (CATE) function. Meta-algorithms build on base algorithms---such as Random Forests (RF), Bayesian Additive Regression Trees (BART) or neural networks---to estimate the CATE, a function that the base algorithms are not designed to estimate directly. We introduce a new meta-algorithm, the X-learner, that is provably efficient when the number of units in one treatment group is much larger than in the other, and can exploit structural properties of the CATE function. For example, if the CATE function is linear and the response functions in treatment and control are Lipschitz continuous, the X-learner can still achieve the parametric rate under regularity conditions. We then introduce versions of the X-learner that use RF and BART as base learners. In extensive simulation studies, the X-learner performs favorably, although none of the meta-learners is uniformly the best. In two persuasion field experiments from political science, we demonstrate how our new X-learner can be used to target treatment regimes and to shed light on underlying mechanisms. A software package is provided that implements our methods

Beam-foil spectrum of nitrogen at ultraviolet wavelengths

Spectrum analysis on foil excited nitrogen beam during acceleration at ultraviolet wavelength

Effect of water quality and season on the population dynamics of Cabomba caroliniana in subtropical Queensland, Australia

Cabomba caroliniana is a submersed aquatic macrophyte that originates from the Americas and is currently invading temperate, subtropical, and tropical freshwater habitats around the world. Despite being a nuisance in many countries, little is known about its ecology. We monitored C. caroliniana populations in three reservoirs in subtropical Queensland, Australia, over 5.5 years. Although biomass, stem length, and plant density of the C. caroliniana stands fluctuated over time, they did not exhibit clear seasonal patterns. Water depth was the most important environmental factor explaining C. caroliniana abundance. Plant biomass was greatest at depths from 2–4 m and rooted plants were not found beyond 5 m. Plant density was greatest in shallow water and decreased with depth, most likely as a function of decreasing light and increasing physical stress. We tested the effect of a range of water physico-chemical parameters. The concentration of phosphorus in the water column was the variable that explained most of the variation in C. caroliniana population parameters. We found that in subtropical Australia, C. caroliniana abundance does not appear to be affected by seasonal conditions but is influenced by other environmental variables such as water depth and nutrient loading. Therefore, further spread will more likely be governed by local habitat rather than climatic conditions

Regulation of Meiotic Cohesion and Chromosome Core Morphogenesis during Pachytene in Drosophila Oocytes

During meiosis, cohesion between sister chromatids is required for normal levels of homologous recombination, maintenance of chiasmata and accurate chromosome segregation during both divisions. In Drosophila, null mutations in the ord gene abolish meiotic cohesion, although how ORD protein promotes cohesion has remained elusive. We show that SMC subunits of the cohesin complex colocalize with ORD at centromeres of ovarian germ-line cells. In addition, cohesin SMCs and ORD are visible along the length of meiotic chromosomes during pachytene and remain associated with chromosome cores following DNase I digestion. In flies lacking ORD activity, cohesin SMCs fail to accumulate at oocyte centromeres. Although SMC1 and SMC3 localization along chromosome cores appears normal during early pachytene in ord mutant oocytes, the cores disassemble as meiosis progresses. These data suggest that cohesin loading and/or accumulation at centromeres versus arms is under differential control during Drosophila meiosis. Our experiments also reveal that the alpha-kleisin C(2)M is required for the assembly of chromosome cores during pachytene but is not involved in recruitment of cohesin SMCs to the centromeres. We present a model for how chromosome cores are assembled during Drosophila meiosis and the role of ORD in meiotic cohesion, chromosome core maintenance and homologous recombination

Surface-mediated attraction between colloids

We investigate the equilibrium properties of a colloidal solution in contact with a soft interface. As a result of symmetry breaking, surface effects are generally prevailing in confined colloidal systems. In this Letter, particular emphasis is given to surface fluctuations and their consequences on the local (re)organization of the suspension. It is shown that particles experience a significant effective interaction in the vicinity of the interface. This potential of mean force is always attractive, with range controlled by the surface correlation length. We suggest that, under some circumstances, surface-induced attraction may have a strong influence on the local particle distribution

Effect of water quality and season on the population dynamics of Cabomba caroliniana in subtropical Queensland, Australia

Cabomba caroliniana is a submersed aquatic macrophyte that originates from the Americas and is currently invading temperate, subtropical, and tropical freshwater habitats around the world. Despite being a nuisance in many countries, little is known about its ecology. We monitored C. caroliniana populations in three reservoirs in subtropical Queensland, Australia, over 5.5 years. Although biomass, stem length, and plant density of the C. caroliniana stands fluctuated over time, they did not exhibit clear seasonal patterns. Water depth was the most important environmental factor explaining C. caroliniana abundance. Plant biomass was greatest at depths from 2–4 m and rooted plants were not found beyond 5 m. Plant density was greatest in shallow water and decreased with depth, most likely as a function of decreasing light and increasing physical stress. We tested the effect of a range of water physico-chemical parameters. The concentration of phosphorus in the water column was the variable that explained most of the variation in C. caroliniana population parameters. We found that in subtropical Australia, C. caroliniana abundance does not appear to be affected by seasonal conditions but is influenced by other environmental variables such as water depth and nutrient loading. Therefore, further spread will more likely be governed by local habitat rather than climatic conditions

AN ANALYTICAL APPROACH TO HUMAN RIGHTS VIOLATIONS IN EGYPT FROM THE START OF THE REVOLUTION TO PRESENT DAY

poster abstractThere are so many current issues that are in violation of Human Rights around the world and the purpose of my research is to address the ones being violated specifically in Egypt from the beginning of the protests to what is currently taking place. Not only will we attempt to find out the numerous human violations in Egypt, but also try to explain why action was not taken and what should have been done instead. Egypt is one of the countries in the Middle-East that has had the most progression through the Arab Spring, but whether the outcome is good or not is still too early to tell. We hope to begin our research with the examination and better understanding of the country’s internal politics and its treatment of human rights throughout history. We plan to utilize a multitude of sources such as international law documents, domestic and foreign articles from the time period of the revolution, interviews with participants of the revolution and experts on Egypt, and multimedia sources including Facebook and Twitter. With this research, our goal is to achieve a better understanding of the human rights situation during the Egyptian revolution and its impact on the country’s progress

Are organically grown apples tastier and healthier? A comparative field study using conventional and alternative methods to measure fruit quality

Since 1994 important supermarket chains in Switzerland successfully sell apples from verified organic production. However, in supermarkets customers often ask whether there are, apart from a more environmentally friendly production, objective arguments of inner fruit quality that justify the higher prices of organic apples. In a field study with the ‘Golden Delicious’ cultivar, we harvested fruits of 5 pairs of organic/integrated fruit farms. The orchards within the pairs were less than 1 km from each other and were similar in micro climate, soil conditions and planting system. Maximum distance between the pairs was 180 km. To measure inner fruit quality we investigated at the beginning and at the end of cold storage (i) standard parameters (firmness, sugar, malic acid, mineral elements etc.); (ii) taste parameters by repeated panel tests; (iii) components that are good for human health (phenols, selenium, fibres, vitamin C and E) and (iv) fruit «vitality quality» by holistic approaches using image forming technique (crystallisation in copper chloride, and chromatography after Pfeiffer), degradation tests and feeding preference tests with laboratory rats. All fruit samples of organic orchards had significantly firmer fruit flesh (14%) and had 15% higher taste marks than conventional ones. P-content was 31% higher (p < 0.01) in organic apples and was closely correlated with technical quality (r2 = 0.93) and sensory score (r2 = 0.69). Content of phenols (mainly flavanols) was 19% and image forming quality 60% higher in organic apples. The picture producing method distinguished 100% correctly the organic and integrated samples and was closely in line with technical quality (r2 = 0.68). The results show that organically grown apples can have an outstanding inner quality. However, for generalizable conclusions more extensive studies are necessary