Is the PAMELA Positron Excess Winos?

Recently the PAMELA satellite-based experiment reported an excess of galactic positrons that could be a signal of annihilating dark matter. The PAMELA data may admit an interpretation as a signal from a wino-like LSP of mass about 200 GeV, normalized to the local relic density, and annihilating mainly into W-bosons. This possibility requires the current conventional estimate for the energy loss rate of positrons be too large by roughly a factor of five. Data from anti-protons and gamma rays also provide tension with this interpretation, but there are significant astrophysical uncertainties associated with their propagation. It is not unreasonable to take this well-motivated candidate seriously, at present, in part because it can be tested in several ways soon. The forthcoming PAMELA data on higher energy positrons and the FGST (formerly GLAST) data, should provide important clues as to whether this scenario is correct. If correct, the wino interpretation implies a cosmological history in which the dark matter does not originate in thermal equilibrium.Comment: 7 pages, 4 figue

Trading Consequences: A Case Study of Combining Text Mining and Visualization to Facilitate Document Exploration

Large-scale digitization efforts and the availability of computational methods, including text mining and information visualization, have enabled new approaches to historical research. However, we lack case studies of how these methods can be applied in practice and what their potential impact may be. Trading Consequences is an interdisciplinary research project between environmental historians, computational linguists and visualization specialists. It combines text mining and information visualization alongside traditional research methods in environmental history to explore commodity trade in the nineteenth century from a global perspective. Along with a unique data corpus, this project developed three visual interfaces to enable the exploration and analysis of four historical document collections, consisting of approximately 200,000 documents and 11 million pages related to commodity trading. In this paper we discuss the potential and limitations of our approach based on feedback from historians we elicited over the course of this project. Informing the design of such tools in the larger context of digital humanities projects, our findings show that visualization-based interfaces are a valuable starting point to large-scale explorations in historical research. Besides providing multiple visual perspectives on the document collection to highlight general patterns, it is important to provide a context in which these patterns occur and offer analytical tools for more in-depth investigations.PostprintPeer reviewe

Age of Immigration and Adult Labor Market Outcomes: Childhood Environment in the Country of Origin Matters

This paper builds on previous studies that have examined the effect of age of immigration on adult labor market outcomes by considering the potential impact of the childhood environment in the country of origin. 2000 United States Census data and historical child mortality data is used to quantify the impact of the childhood environment in the country of origin on the effect of age of immigration on adult labor market outcomes. Results from children who immigrated to the United States between ages zero and ten indicate that the impact of age of immigration on adult labor market outcomes is more negative for immigrants arriving from countries with poor childhood environments

The WN adaptive method for numerical solution of particle transport problems

The source and nature, as well as the history of ray-effects, is described. A benchmark code, using piecewise constant functions in angle and diamond differencing in space, is derived in order to analyze four sample problems. The results of this analysis are presented showing the ray effects and how increasing the resolution (number of angles) eliminates them. The theory of wavelets is introduced and the use of wavelets in multiresolution analysis is discussed. This multiresolution analysis is applied to the transport equation, and equations that can be solved to calculate the coefficients in the wavelet expansion for the angular flux are derived. The use of thresholding to eliminate wavelet coefficients that are not required to adequately solve a problem is then discussed. An iterative sweeping algorithm, called the SN-WN method, is derived to solve the wavelet-based equations. The convergence of the SN-WN method is discussed. An algorithm for solving the equations is derived, by solving a matrix within each cell directly for the expansion coefficients. This algorithm is called the CWWN method. The results of applying the CW-WN method to the benchmark problems are presented. These results show that more research is needed to improve the convergence of the SN-WN method, and that the CW-WN method is computationally too costly to be seriously considered

Age of Immigration and Adult Labor Market Outcomes: Childhood Environment in the Country of Origin Matters

This paper builds on previous studies that have examined the effect of age of immigration on adult labor market outcomes by considering the potential impact of the childhood environment in the country of origin. 2000 United States Census data and historical child mortality data is used to quantify the impact of the childhood environment in the country of origin on the effect of age of immigration on adult labor market outcomes. Results from children who immigrated to the United States between ages zero and ten indicate that the impact of age of immigration on adult labor market outcomes is more negative for immigrants arriving from countries with poor childhood environments

Taurine: An Indispensable Ingredient in the Development of Sustainable Aquafeeds

Aquaculture as a global industry is at a crossroad; increased production cannot rely on the unsustainable harvest of forage fish for feed production. The use of fishmeal and fish oil as components in feeds for aquaculture, most notably for high value marine carnivores must be reduced or eliminated. The most promising and sustainable sources of replacement feed must be plant derived, such as soybean meal, wheat flour, and corn gluten along with dozens of other plant derived sources. Likewise for fish oil the most promising sources are plant oils such as soybean and canola oil supplemented with necessary omega-3 fatty acids. This work was undertaken to examine the effects of switching marine carnivores from fishmeal-based feeds to fishmeal-free, plant-based diets. The majority of this research has been conducted with cobia, Rachycentron canadum, a promising species for intensive aquaculture due to its rapid growth rates, high disease resistance, and lack of a major commercial fishery as competition. A variety of plant proteins, plant protein blends and alternative lipid sources were examined for digestibility and efficacy as fishmeal replacement sources in regards to their effects on growth rates, feed conversion, and a range of physiological characteristics. This work has explored the hypothesis that marine carnivores have lost the ability to synthesize taurine, a non-protein amino acid, in sufficient quantities and must therefore be supplied through the diet, and should be considered essential for all marine carnivores. By measurement of gene expression of the genes in taurine biosynthesis, this work shows that cobia do not possess the ability to regulate taurine biosynthesis confirming taurine must be supplied through the diet. Overall, this work has developed multiple plant protein-based feeds that perform equivalently or better than commercial and commercial-like diets. Taurine has been shown to be an essential ingredient when seeking to reduce or preferably, eliminate fishmeal and thereby making aquaculture sustainable in providing protein to meet the world's growing population

The ηNN\eta NN-system at low energy within a three-body approach

The role of the $\eta NN$-interaction is studied in the low energy regime in $\eta$-deuteron reactions as well as in coherent and incoherent $\eta$-photoproduction on the deuteron using a three-body model with separable two-body interactions. The three-body approach turns out to be quite essential in the most important lowest partial wave. Results are presented for differential and total cross sections as well as for the $\eta$-meson spectrum. They differ significantly from those predicted by a simple rescattering model in which only first-order $\eta N$- and $NN$-interactions in the final state are considered. The major features of the experimental data of $\eta$-photoproduction in the near-threshold region are well reproduced.Comment: 20 pages revtex including 10 figures, revised version accepted for publication in Nucl. Phys.

Moduli Stabilization in Brane Gas Cosmology with Superpotentials

In the context of brane gas cosmology in superstring theory, we show why it is impossible to simultaneously stabilize the dilaton and the radion with a general gas of strings (including massless modes) and D-branes. Although this requires invoking a different mechanism to stabilize these moduli fields, we find that the brane gas can still play a crucial role in the early universe in assisting moduli stabilization. We show that a modest energy density of specific types of brane gas can solve the overshoot problem that typically afflicts potentials arising from gaugino condensation.Comment: minor changes to match the journal versio

‘Communities of resistance’ and the use of newspaper discussion boards Polish workers in Japanese foreign investments

This is the peer reviewed version of the following article: Maciej Bancarzewski, and Jane Hardy, ‘‘Communities of resistance’ and the use of newspaper discussion boards: Polish workers in Japanese foreign investments’, New Technology, Work and Employment, Vol. 32 (2): 160-173, July 2017, which has been published in final form at https://doi.org/10.1111/ntwe.12091. Under embargo until 25 July 2019. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.This article examines the content of two hundred posts on newspaper discussion boards by workers in a cluster of Japanese foreign investments in Poland. The conclusions are first, that the material experiences of workers generate a set of themes in relation to the labour process with regard to wages and working conditions, bullying and monitoring that exhibit similarities across countries. Second, we argue that an analysis of the discourse used is shaped by political and institutional conditions, which reveal national differences in how workers perceive and locate their exploitation. Finally, in relation to debates about workers’ resistance and the use of the internet we argue that the interaction of themes related to the material experience of work are intertwined with institutionally embedded understandings of exploitation, which not only enable a shared framework for venting, but also provide the basis for a community of resistance.Peer reviewedFinal Accepted Versio