Constraining the Origin of Local Positrons with HAWC TeV Gamma-Ray Observations of Two Nearby Pulsar Wind Nebulae

The HAWC Gamma-Ray Observatory has reported the discovery of TeV gamma-ray emission extending several degrees around the positions of Geminga and B0656+14 pulsars. Assuming these gamma rays are produced by inverse Compton scattering off low-energy photons in electron halos around the pulsars, we determine the diffusion of electrons and positrons in the local interstellar medium. We will present the morphological and spectral studies of these two VHE gamma-ray sources and the derived positron spectrum at Earth.Comment: Presented at the 35th International Cosmic Ray Conference (ICRC2017), Bexco, Busan, Korea. See arXiv:1708.02572 for all HAWC contribution

The financial impact of ISO 9000 certification in the United States: an empirical analysis.

The ISO 9000 series of quality management systems standards, introduced in 1986, has been adopted at over 560,000 locations worldwide. Anecdotal evidence suggests that firms can achieve internal benefits such as quality or productivity improvements or that certification can help firms maintain or increase their market share, or both. Others argue that the standard is too generic to cause performance improvement but can be seen as a signal of good management. In this paper, we track financial performance from 1987 to 1997 of all publicly traded ISO 9000 certified manufacturing firms in the United States with SIC codes 2000–3999, and test whether ISO 9000 certification leads to productivity improvements, market benefits, and improved financial performance. We employ event-study methods, matching each certified firm to a control group of one or more noncertified firms in the same industry with similar precertification size and/or return on assets. We find that firms’ decision to seek their first ISO 9000 certification was indeed followed by significant abnormal improvements in financial performance, though the exact timing and magnitude of this effect depend on the specification of the control group. Three years after certification, the certified firms do display strongly significant abnormal performance under all control-group specifications. The degree to which the precise results vary across control-group specifications indicates that event studies should always include extensive sensitivity analysis, for instance matching by size and performance separately and jointly, using both single firms and portfolios as controls.ISO 9000; Quality management; Standards; Financial; Empirical; Event study; Compustat;

Constraining the Diffusion Coefficient with HAWC TeV Gamma-Ray Observations of Two Nearby Pulsar Wind Nebulae

Nearby electron/positron accelerators, mostly Pulsar Wind Nebulae (PWNe), have been proposed as potential origins of the positron excess above 10 GeV. The HAWC Observatory reveals two very extended sources spatially coincident with two nearby middle-aged pulsars: Geminga and PSR B0656+14, suggesting ultrarelativistic electrons/positrons accelerated in our backyard. Morphological studies on these two PWNe provide a constraint on the diffusion coefficient at HAWC energies. In this poster, we will present the model development and morphological studies on these PWNe, and the derived diffusion coefficient that best fits the data.Comment: Presented at the 35th International Cosmic Ray Conference (ICRC2017), Bexco, Busan, Korea. See arXiv:1708.02572 for all HAWC contribution

Tracing the origin of the panda's thumb

© 2015, Springer-Verlag Berlin Heidelberg. We investigate the relative development of the carnivoran radial sesamoids to untangle the evolution of this iconic structure. In the pandas (both giant and red), this `false thumb¿ is known to perform a grasping role during bamboo feeding in both the red and giant pandas. An original locomotor role has been inferred for ailurids, but this remains to be ascertained for ursids. A large sample of radial sesamoids of Indarctos arctoides from the Miocene of Batallones-3 (Spain) indicates that this early ailuropodine bear displayed a relatively hypertrophied radial sesamoid, with a configuration more similar to that of the red panda and other carnivorans than to that of giant pandas. This false thumb is the first evidence of this feature in the Ursidae, which can be linked to a more herbivorous diet. Moreover, in the two extant pandas, the false thumb should not be interpreted as an anatomical convergence, but as an exaptive convergence regarding its use during the bamboo feeding, which changes the evolutionary view of this singular structure.This study was supported by the Spanish Ministerio de Economía y Competitividad (CGL2011-25754, CGL2011-28681 and RYC–2009–04533 to D.M.A.). A.V. is a researcher in formation in the CSIC program JAE-PRE_CP2011 (CSIC program‘ Junta para la ampliación de estudios’), co-funded by the European Social Fund and has received funding from the European Union’s Seventh Framework Programme (FP7/2007–2013) under grant agreement no. 226506 (SYNTHESYS; SE-TAF-3637),Peer Reviewe

3D Multi-pass finite element welding modelling of butt-welded plate specimen

Congreso celebrado en la Escuela de Arquitectura de la Universidad de Sevilla desde el 24 hasta el 26 de junio de 2015.A multi-pass welding of a thin rectangular (dog-bone shaped) butt joint plate is numerically simulated as a coupled thermo-mechanical transient problem. The simulation uses an “element-birth” technique to simplify the complexity of the problem. The paper discusses the challenges of the simulation of a multi-pass weld problem and the utility of the results for practical applications. The final solution shows crucial stress distributions in a challenging geometry where large thermal transients and gradients are created by the welding procedure. The results also indicate the plastic yielding of the weld-joint after extensive cooling of the joined plate. The displacements from the results can be used to estimate the extent of distortions qualitatively. Despite minimal resources (2 CPUs on a standard Intel desktop architecture and 2 GB RAM over duration of 4 days) the procedure is able to provide adequate details in predicting residual stresses for multi-pass welded components

Inferencias paleoambientales del Mioceno Medio de Somosaguas (Pozuelo de Alarcón, Madrid) basadas en la estructura de tamaños coroporales de su fauna de mamíferos

El presente trabajo es una aproximación a la inferencia de las condiciones paleoambientales y paleoclimáticas del yacimiento de vertebrados fósiles del Mioceno medio de Somosaguas (Pozuelo de Alarcón, Madrid; biozona E, MN5, Aragoniense medio). Realizamos una serie de análisis discriminantes sobre las variables descritas para la estructura de tamaños corporales de las comunidades de mamíferos mediante el cenograma y el espectro de tamaños corporales. A partir de la comparación con comunidades actuales pertenecientes a bosque tropical deciduo, sabana y desierto subtropical, nuestros resultados sugieren que el ecosistema de Somosaguas podría estar situado en un área de semi-desierto, reflejando un ecotono entre sabana y desierto. Esto coincide con la información obtenida a partir de otros estudios

Asset Ownership and Foreign-Market Entry

This paper examines the link between a firm?s owership of productive assets and its choice of foreign-market entry strategy. We find that, controlling for industry- and country-specific characteristics, the most productive firms (i.e., those owning the most assets) will enter through greenfield investment, less productive ones will choose M&A, and the least productive ones will export. In addition, the most productive firms are shown to prefer whole ownership to a joint venture. These predictions are confirmed in an econometric analysis of Japanese firm-level data. --Foreign direct investment,merger and acquisition,joint venture,greenfield investment,firm heterogeneity,productivity