Altruism and Voluntary Provision of Public Goods

We study how people's predisposition towards altruism, as measured by tools developed by psychologists, affects their behavior in a voluntary contributions public good experiment. Earlier experiments provide evidence against the strong free rider hypothesis; however, contributions to the public good decrease with repetition. We investigate whether a high level of contributions can be sustained in groups of subjects who have been pre-selected on the basis of their altruistic inclinations. In the first stage of the experiment, each subject responds to a psychology questionnaire that measures various dimensions of one's personality. The subjects are then matched in groups according to their altruism scores, and engage in a voluntary contribution game. We consider whether the levels and dynamics of group contributions differ significantly between the groups with altruists and non-altruists. We find that subjects' altruism has a weak but positive effect on group behavior in the public good game.

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Edward SAID, Culture and imperialis

Altruism and voluntary provision of public goods

We study how people's predisposition towards altruism affects their behavior in a voluntary contributions public good experiment. We investigate whether a high level of contributions can be sustained in groups of subjects who have been pre-selected on the basis of their altruistic inclinations. In the first stage of the experiment, each subject responds to a psychology questionnaire that measures various dimensions of one''s personality. The subjects are then matched in groups according to their altruism scores, and engage in a voluntary contributions game. We consider whether the levels and dynamics of group contributions differ significantly between the groups with altruists and non-altruists. We find that subjects'' altruism has only a weak positive effect on group behavior in the public good game.Altruism

Discovery of tetragonal almandine, (Fe,Mg,Ca,Na)_3(Al,Si,Mg)_2Si_3O_(12), a new high-pressure mineral in Shergotty

Introduction: During a nanomineralogy investigation of the Shergotty meteorite, we have identified a new shock-induced high-pressure silicate, majoritic almandine with a tetragonal I4_1/ɑ structure, in an impact melt pocket. Field-emission scanning electron microscope, electron back-scatter diffraction, electron microprobe and synchrotron diffraction were used to characterize its chemical composition, structure, and associated phases. Tetragonal majorite (Mg_3(SiMg)Si_3O_(12)) with the I4_1/ɑ structure was synthesized [e.g., 1] and found later in the Tenham chondrite [2,3]. Tetragonal almandine-pyrope phase (TAPP) with the I-42d structure was reported to occur as inclusions in lowermantle diamonds [4]. We present here the first occurrence of tetragonal almandine with the I41/a structure in a shocked meteorite from Mars as a new high-pressure phase

An in silico MS/MS library for automatic annotation of novel FAHFA lipids.

BackgroundA new lipid class named 'fatty acid esters of hydroxyl fatty acids' (FAHFA) was recently discovered in mammalian adipose tissue and in blood plasma and some FAHFAs were found to be associated with type 2 diabetes. To facilitate the automatic annotation of FAHFAs in biological specimens, a tandem mass spectra (MS/MS) library is needed. Due to the limitation of the commercial available standard compounds, we proposed building an in silico MS/MS library to extend the coverage of molecules.ResultsWe developed a computer-generated library with 3267 tandem mass spectra (MS/MS) for 1089 FAHFA species. FAHFA spectra were generated based on authentic standards with negative mode electrospray ionization and 10, 20, and 40 V collision induced dissociation at 4 spectra/s as used in in ultra-high performance liquid chromatography-QTOF mass spectrometry studies. However, positional information of the hydroxyl group is only obtained either at lower QTOF spectra acquisition rates of 1 spectrum/s or at the MS(3) level in ion trap instruments. Therefore, an additional set of 4290 fragment-rich MS/MS spectra was created to enable distinguishing positional FAHFA isomers. The library was generated based on ion fragmentations and ion intensities of FAHFA external reference standards, developing a heuristic model for fragmentation rules and extending these rules to large swaths of computer-generated structures of FAHFAs with varying chain lengths, degrees of unsaturation and hydroxyl group positions. Subsequently, we validated the new in silico library by discovering several new FAHFA species in egg yolk, showing that this library enables high-throughput screening of FAHFA lipids in various biological matrices.ConclusionsThe developed library and templates are freely available for commercial or noncommercial use at http://fiehnlab.ucdavis.edu/staff/yanma/fahfa-lipid-library. This in silico MS/MS library allows users to annotate FAHFAs from accurate mass tandem mass spectra in an easy and fast manner with NIST MS Search or PepSearch software. The developing template is provided for advanced users to modify the parameters and export customized libraries according to their instrument features. Graphical abstractExample of experimental and in silico MS/MS spectra for FAHFA lipids

Contributions to material failure numerical simulation in finite deformation settings. Elastoplastic models

Partiendo de la Aproximación de continuo de discontinuidades fuertes (CSDA) como marco para modelar el fenómeno de localización de deformaciones y discontinuidades del campo de desplazamientos, el presente artículo extiende resultados previos obtenidos por los autores empleando cinemáticas de deformación infinitesimal y finita en modelos degradables. Mediante el análisis de discontinuidad fuerte, y adoptando un modelo continuo (tensión-deformación) elastoplástico isótropo, se deriva el modelo constitutivo discreto proyectado (vector tracción versus salto del campo de esplazamiento), junto con las condiciones de discontinuidad fuerte que restringen los estados tensionales en el régimen discontinuo. Se establece una comparación entre los modelos constitutivos discretos proyectados obtenidos con ambas cinemáticas (deformaciones infinitesimales y finitas). Al final del artículo se expone una serie de ensayos numéricos con objeto de corroborar la teoría del modelo propuesto y de enfatizar el papel que desempeña la cinemática de grandes deformaciones en los resultados obtenidos.Peer Reviewe