Atomic data from the Iron Project. LXIV. Radiative transition rates and collision strengths for Ca II

This work reports radiative transition rates and electron impact excitation rate coefficients for levels of the n= 3, 4, 5, 6, 7, 8 configurations of Ca II. The radiative data were computed using the Thomas-Fermi-Dirac central potential method in the frozen core approximation and includes the polarization interaction between the valence electron and the core using a model potential. This method allows for configuration interactions (CI) and relativistic effects in the Breit-Pauli formalism. Collision strengths in LS-coupling were calculated in the close coupling approximation with the R-matrix method. Then, fine structure collision strengths were obtained by means of the intermediate-coupling frame transformation (ICFT) method which accounts for spin-orbit coupling effects. We present extensive comparisons with the most recent calculations and measurements for Ca II as well as a comparison between the core polarization results and the "unpolarized" values. We find that core polarization affects the computed lifetimes by up to 20%. Our results are in very close agreement with recent measurements for the lifetimes of metastable levels. The present collision strengths were integrated over a Maxwellian distribution of electron energies and the resulting effective collision strengths are given for a wide range of temperatures. Our effective collision strengths for the resonance transitions are within ~11% from previous values derived from experimental measurements, but disagree with latter computations using the distorted wave approximation.Comment: 8 pages, 4 figures. The atomic data from this work, including energy levels, A-values, and effective collision strengths, is available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A

A Forecasting Approach to Improve Logistics Planning in the Colombian Air Force

The Colombian Air Force recently installed a logistics operating system to improve the logistics system. However, the inventory cost and turnover have not stopped growing; subsequently, the operational readiness has been affected. The purpose of the study was to compare the performance of several forecasting techniques to improve the current planning process of aircraft parts in the CAF. The research used five phases. The first phase identified the relevant factors and the forecasting techniques selected for the experiment. The factors were repairability, demandability and uniqueness. The forecasting methods were single and double exponential, moving average, autoregression and linear regression. The third and fourth phases simulate additional demand data. It was found that single exponential and moving average perform better than the others. The fifth phase found that the forecasting system can provide substantial savings to the logistics system. Finally, it can be concluded that demand for most spare parts cannot be predicted because forecasts always contain errors. Then, it is necessary to consider additional improvements in logistics operations to make it easier to live with demand uncertainty. Among such improvements would be a shortening of the resupply time, the procurement lead time, and of the repair cycle for spare parts

Contesting Social and Historical Erasure: Membership in La Prensa

Published in UNM Press book entitled Nuevomexicano Cultural Legacy: Forms, Agencies and Discourse

Evaluando los niveles tróficos de dos tiburones oceánicos del Océano Pacífico suroriental

Indexación: Web of ScienceStable isotope analyses for shortfin mako (Isurus oxyrinchus) and blue sharks (Prionace glauca) were conducted to assess their trophic position in two periods of time (before 1980 and after 2000) in the Southeastern Pacific waters (SEP). Both sharks showed that their trophic position decreased over time (P < 0.05). Many factors could be involved in this change such as dietary shifts, prey availability, or indirect fishing effects in SEP waters.RESUMEN. Para evaluar los niveles tróficos de los tiburones marrajo (Isurus oxyrinchus) y azulejo (Prionace glauca) en dos períodos de tiempo (previo a 1980 y posterior al 2000) en aguas del Pacífico suroriental (SEP), se realizaron análisis de isótopos estables. Ambos tiburones mostraron un descenso del nivel trófico en el tiempo (P < 0,05). Varios son los factores que pueden estar involucrados en este evento, como los cambios dietarios, la disponibilidad de las presas o los efectos indirectos de la pesquería en aguas del Pacífico suroriental.http://www.lajar.cl/pdf/imar/v44n2/Art%C3%ADculo_44_2_25.pd

siRNA knockdown of SPHK1 in vivo protects mice from systemic, type-I Allergy.

Systemic anaphylaxis is considered to be a typical immediate hypersensitivity response, determined by the activation of immune cells,&#xd;&#xa;via antigen-induced aggregation of IgE-sensitized Fc&#x3b5;RI cells. Perhaps most the important cells, in the immediate hypersensitivity responses, are mast cells. We have previously shown that SPHK1 plays a key role in the intracellular signaling pathways triggered by FceRI aggregation on human&#xd;&#xa;mast cells. More recently, we performed a genome-wide gene expression profiling of human mast cells, sensitized with IgE alone, or stimulated by Fc&#x3b5;RI aggregation. We found that sphingosine kinase 1 (SPHK1) was one&#xd;&#xa;of genes activated at the earlier stages of mast cell activation, including during sensitization. Moreover, SPHK1 has been shown, by us and others, to be a key player in the intracellular signaling pathways triggered by&#xd;&#xa;several immune-receptors, including fMLP, C5a, and Fcg- and Fcereceptors. Here we have investigated the in vivo role of SPHK1 in allergy, using a specific siRNA to knockdown SPHK1 in vivo. Our results support a role for&#xd;&#xa;SPHK1 in the inflammatory responses that share clinical, immunological, and histological features of type I hypersensitivity. Thus, mice pretreated with the siRNA for SPHK1 were protected from the IgE mediated allergic&#xd;&#xa;reactions including: temperature changes, histamine release, cytokine production, cell-adhesion molecule expression, and immune cell infiltration into the lungs

Error Cascades in Observational Learning: An Experiment on the Chinos Game

The paper reports an experimental study based on a variant of the popular Chinos game, which is used as a simple but paradigmatic instance of observational learning. There are three players, arranged in sequence, each of whom wins a fixed price if she manages to guess the total number of coins lying in everybody’s hands. Our evidence shows that, despite the remarkable frequency of equilibrium outcomes, deviations from optimal play are also significant. And when such deviations occur, we find that, for any given player position, the probability of a mistake is increasing in the probability of a mistake of her predecessors. This is what we call an error cascade, which we rationalize by way of a simple model of “noisy equilibrium”.positional learning, error cascades

Community Economic Development and the Latino Experience

Just as people had high expectations for the Great Society programs instituted to address poverty after the Watts riots of 1965 so, too, did people have high hopes for a turning point in federal initiatives to address the plight of the urban poor after the Los Angeles rebellion of 1992. Indeed, both analysts and community activists were hopeful that a more sympathetic administration would be able to capitalize on the political momentum that resulted from their electoral victory and implement somewhat unpopular programs in Congress. This could not have come at a better time for blacks and Latinos in the cities who make up a large part of the urban poverty population. Over the past two decades, concentration of blacks and Latinos in segregated and impoverished urban communities has increased, thus making them more vulnerable to the negative effects of urban restructuring. In many ways, easing the plight of the urban poor is not simply dependent on the existence of federal urban initiatives, but on their success. In this paper, we argue that the success of urban economic development largely depends on the articulation of these programs to communities and, in particular, on recognizing the role that racial and ethnic networks play in mobilizing resources around an economic development agenda. We will present a case study of economic development in Latino communities as an example of how an understanding of race and ethnicity may contribute to more effective public policy

Temperature dependent charge transport mechanisms in carbon sphere/polymer composites

Carbon spheres (CS) with diameters in the range $2 - 10 \mu m$ were prepared via hydrolysis of a sucrose solution at $200^o C,$ and later annealed in $N_2$ at $800^o C.$ The spheres were highly conducting but difficult to process into thin films or pressed pellets. In our previous work, composite samples of CS and the insulating polymer polyethylene oxide (PEO) were prepared and their charge transport was analyzed in the temperature range $80 K < T < 300 K.$ Here, we analyze charge transport in CS coated with a thin polyaniline (PANi) film doped with hydrochloric acid (HCl), in the same temperature range. The goal is to study charge transport in the CS using a conducting polymer (PANi) as a binder and compare with that occurring at CS/PEO. A conductivity maxima was observed in the CS/PEO composite but was absent in CS/PANi. Our data analysis shows that variable range hopping of electrons between polymeric chains in PANi-filled gaps between CS takes on a predominant part in transport through CS/PANi composites, whereas in CS/PEO composites, electrons travel through gaps between CS solely by means of direct tunneling. This difference in transport mechanisms results in different temperature dependences of the conductivity.Comment: 7 pages, 6 figure

The influence of electron collisions on non-LTE Li line formation in stellar atmospheres

The influence of the uncertainties in the rate coefficient data for electron-impact excitation and ionization on non-LTE Li line formation in cool stellar atmospheres is investigated. We examine the electron collision data used in previous non-LTE calculations and compare them to recent calculations that use convergent close-coupling (CCC) techniques and to our own calculations using the R-matrix with pseudostates (RMPS) method. We find excellent agreement between rate coefficients from the CCC and RMPS calculations, and reasonable agreement between these data and the semi-empirical data used in non-LTE calculations up to now. The results of non-LTE calculations using the old and new data sets are compared and only small differences found: about 0.01 dex (~ 2%) or less in the abundance corrections. We therefore conclude that the influence on non-LTE calculations of uncertainties in the electron collision data is negligible. Indeed, together with the collision data for the charge exchange process Li(3s) + H Li^+ + H^- now available, and barring the existence of an unknown important collisional process, the collisional data in general is not a source of significant uncertainty in non-LTE Li line formation calculations.Comment: 8 pages, accepted by Astronomy and Astrophysics; Replaced with minor corrections following proof

Quasar Feedback in the Ultraluminous Infrared Galaxy F11119+3257: Connecting the Accretion Disk Wind with the Large-Scale Molecular Outflow

In Tombesi et al. (2015), we reported the first direct evidence for a quasar accretion disk wind driving a massive molecular outflow. The target was F11119+3257, an ultraluminous infrared galaxy (ULIRG) with unambiguous type-1 quasar optical broad emission lines. The energetics of the accretion disk wind and molecular outflow were found to be consistent with the predictions of quasar feedback models where the molecular outflow is driven by a hot energy-conserving bubble inflated by the inner quasar accretion disk wind. However, this conclusion was uncertain because the energetics were estimated from the optically thick OH 119 um transition profile observed with Herschel. Here, we independently confirm the presence of the molecular outflow in F11119+3257, based on the detection of broad wings in the CO(1-0) profile derived from ALMA observations. The broad CO(1-0) line emission appears to be spatially extended on a scale of at least ~7 kpc from the center. Mass outflow rate, momentum flux, and mechanical power of (80-200) R_7^{-1} M_sun/yr, (1.5-3.0) R_7^{-1} L_AGN/c, and (0.15-0.40)% R_7^{-1} L_AGN are inferred from these data, assuming a CO-to-H_2 conversion factor appropriate for a ULIRG (R_7 is the radius of the outflow normalized to 7 kpc and L_AGN is the AGN luminosity). These rates are time-averaged over a flow time scale of 7x10^6 yrs. They are similar to the OH-based rates time-averaged over a flow time scale of 4x10^5 yrs, but about a factor 4 smaller than the local ("instantaneous"; <10^5 yrs) OH-based estimates cited in Tombesi et al. The implications of these new results are discussed in the context of time-variable quasar-mode feedback and galaxy evolution. The need for an energy-conserving bubble to explain the molecular outflow is also re-examined.Comment: 15 pages, 6 figures, 4 tables, accepted for publication in Ap