582 research outputs found

    When a precedent of donation favors defection in the Prisoner's dilemma

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    In this paper we examine the question of wether a collective activity can influence cooperation in a subsequent repeated one shot prisoner's dilemma (PD) game. We conduct two series of experiments. The first consists of control experiments in which 30 periods of a PD game are played, with a random re-matching of the pairs in every period. In a second series of experiments, subjects first play a donation game and then the PD game. In the donation game they collectively discuss the amount of a donation to a given charity, before putting the question to an individual and anonymous vote. Cooperation levels in the PD games preceded by the donation game are signficantly lower than those observed in the control experiment.DONATION;COOPERATION;DEFECTION;REPEATED ONE SHOT PRISONER'S DILEMMA;EXPERIMENT

    Embryonic and Uterine Characteristics of Diapause

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    L’implantation retardée ou diapause embryonnaire décrit l'arrêt ou le retardement pendant l'embryogenèse. Chez le vison, la diapause est corrélée avec une sécrétion pituitaire insuffisante de la prolactine, ayant pour résultat la différentiation incomplète du corpus luteum et réduction de la progestérone. Des études antérieures suggèrent que le blastocyste de vison en diapause demeure dans un état de quiescence ou se développe lentement. Pour élucider ceci, la réplication de l'ADN a été étudiée. Les résultats démontrent synthèse de l’ADN et prolifération cellulaire dans les embryons au stade de morula, avant la diapause et dans les blastocystes après la réactivation. La réplication de l'ADN a été également détectée dans des blastocystes en diapause et en diapause prolongée. L'implantation est considérée comme une interaction bidirectionnelle entre le blastocyste et l'utérus. Il a été montré que les prostaglandines sont importantes pour la vascularisation de l’utérus au moment de l’implantation et peuvent réactiver l'utérus des visons après la diapause. La concentration protéinique et la localisation de la phospholipase citosolique A2 (CPLA2) et de la cyclooxygenase 2 (COX2) ont été étudiées dans l'utérus de vison. L’expression de la CPLA2 et COX2 étaient sur-régulées au moment de l'implantation. Il est connu que la prolactine active les corpus luteum des visons. L'idée de un lien entre la prolactine et la voie de signalisation des prostaglandines a été testée en mesurant les récepteurs de prolactine. Les résultats montrent une augmentation de l’expression des récepteurs de prolactine à l'implantation suggérant que la prolactine pourrait activer la voie de prostaglandine à l'utérus par son propre récepteur. La conclusion, les embryons pendant la diapause ne sont pas arrêtées complètement et les protéines liées à la voie de prostaglandine sont implique dans la réactivation de l'utérus.Delayed implantation or diapause describes arrest or retardation during embryogenesis. In mink, diapause is related to insufficient pituitary prolactin secretion, resulting in incomplete differentiation of the corpus luteum with reduced progesterone concentration. The mink blastocyst at diapause was believed to be totally quiescent or expanding at a low rate. To explore this, DNA replication was studied. Results showed synthesis of DNA, and thus cell proliferation at the morulae stage before diapause and at the blastocyst following activation. DNA replication was detected not only at diapause but also at extended diapause. Furthermore, implantation is considered as a two-way interaction between the blastocyst and the uterus. It has been shown that prostaglandins are important for vascularization of the uterus and products of the prostaglandin pathway could reactivate the mink uterus following diapause. Protein concentration and localization was studied for cytosolic phospholipase A2 (CPLA2) and cyclooxygenase 2 (COX2) in mink uterus. Expression of CPLA2 and COX2 was up regulated at implantation. It is know that prolactin is the factor that activates the mink corpus luteum. The idea of a link between prolactin and prostaglandin pathway was investigated by quantifying the prolactin receptors in the uterus. Results showed an increase of prolactin receptors at implantation suggesting that prolactin could activate the prostaglandin pathway at the uterus through its own receptor. In conclusion, embryos during diapause are not completely arrested, and proteins related to the prostaglandin pathway are implicated in reactivation of the uterus

    Evaluación de impacto del programa EDUCA y aplicación de la metodología Foster-Greer-Thorbecke FGT

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    El proyecto de TeleEducación EDUCA, del Ministerio de Educación del Ecuador, tiene como objetivo emitir contenidos educativos a través de diferentes medios, con el fin de generar cambios en el comportamiento y actitudes de su grupo objetivo. Los principales ámbitos de las personas, donde se espera obtener impacto son: sus valores; identidad nacional; orgullo nacional, e inclusión cultural y social. En la franja de televisión educativa, la programación está destinada a niños, niñas, adolescentes y familias; no obstante, en los meses en que se realizó este estudio existió un énfasis en la producción audiovisual enfocada en niños y niñas de 6 a 10 años quienes fueron evaluados. Por la señal abierta del programa, se identifica que el mecanismo de selección es la autoselección, por lo cual la metodología de evaluación de impacto utilizada fue un modelo cuasi experimental de Diferencias en Diferencias que incluye una corrección por variables instrumentales. En este sentido, se encuentra evidencia empírica robusta que EDUCA tiene impacto significativo y positivo sobre índices de valores intelectuales, morales y ecológico. Así mismo, se encontró un impacto positivo y significativo respecto a variables de orgullo nacional; identidad nacional, e inclusión cultural y social. Por último, al analizar los índices FGT sobre los índices de valores personales y familiares, identidad nacional, orgullo nacional, e inclusión cultural y social, se evidencia que el ver EDUCA modifica la distribución de los índices del grupo de tratamiento, respecto al grupo de control. Es decir, los valores de los índices Foster-Greer-Thorbecke FGT se modifican y evidencian mejorías una vez que reciben el tratamiento

    Macroeconomía y pétroleo: caso empírico del Ecuador : efectos macroeconómicos de shocks al precio del petróleo en una PEA

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    Los ciclos económicos que ha presentado la economía ecuatoriana en los últimos 35 años tiene características similares a las de una economía emergente, dado que presenta una inversión muy volátil, consumo e inversión pro cíclico y exportaciones netas contra cíclicas. El objetivo de la presente investigación es replicar los hechos estilizados del Ecuador a través de un modelo de equilibrio general dinámico estocástico para una pequeña economía abierta exportadora de petróleo. Se busca explicar los efectos de shocks al precio de petróleo en los ciclos económicos ecuatorianos en el período 1980-2013 usando el enfoque metodológico de RBC. El contraste de las regularidades empíricas plantea que en general los momentos reportados por el modelo son parecidos a los reportados por los datos del Ecuador. El modelo refleja las características estructurales de la economía ecuatoriana y en general de las economías emergentes respecto al consumo de los hogares, el gasto del gobierno, el ingreso total, petrolero y no petrolero

    Probabilistic Model Incorporating Auxiliary Covariates to Control FDR

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    Controlling False Discovery Rate (FDR) while leveraging the side information of multiple hypothesis testing is an emerging research topic in modern data science. Existing methods rely on the test-level covariates while ignoring metrics about test-level covariates. This strategy may not be optimal for complex large-scale problems, where indirect relations often exist among test-level covariates and auxiliary metrics or covariates. We incorporate auxiliary covariates among test-level covariates in a deep Black-Box framework controlling FDR (named as NeurT-FDR) which boosts statistical power and controls FDR for multiple-hypothesis testing. Our method parametrizes the test-level covariates as a neural network and adjusts the auxiliary covariates through a regression framework, which enables flexible handling of high-dimensional features as well as efficient end-to-end optimization. We show that NeurT-FDR makes substantially more discoveries in three real datasets compared to competitive baselines.Comment: Short Version of NeurT-FDR, accepted at CIKM 2022. arXiv admin note: substantial text overlap with arXiv:2101.0980

    Ionized gas kinematics and chemical abundances of low-mass star-forming galaxies at z3z\sim 3

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    We selected 35 low-mass SFGs (7.9<log(M_*/M_{\odot})<10.3) from deep spectroscopic surveys based on their CIII]1908 emission. We used follow-up NIR observations to examine their rest-optical emission lines and identify ionized outflow signatures through broad emission wings detected after Gaussian modeling of [OIII]4959,5007 profiles. We characterized the galaxies' gas-phase metallicity and carbon-to-oxygen (C/O) abundance using a Te-based method via the OIII]1666/[OIII]5007 ratio and photoionization models. We find line ratios and rest-frame EWs characteristic of high-ionization conditions powered by massive stars. Our sample displays mean rest-frame EW([OIII]5007)~560\r{A} while 15% of them show EW([OIII]4959,5007)>1000\r{A} and EW(CIII])>5\r{A}, closely resembling those now seen in EoR galaxies with JWST. We find low gas-phase metallicities 12+log(O/H)~7.5-8.5 and C/O abundances from 23%-128% solar, with no apparent increasing trend with metallicity. From our [OIII]4959,5007 profile modeling, we find that 65% of our sample shows an outflow component, which is shifted relative to the ionized gas systemic velocity, with mean vmaxv_{max}~280 km/s which correlates with the ΣSFR\Sigma_{SFR}. We find that the mass-loading factor μ\mu of our sample is typically lower than in more massive galaxies from literature but higher than in typical local dwarf galaxies. In the stellar mass range covered, we find that μ\mu increases with ΣSFR\Sigma_{SFR} thus suggesting that for a given stellar mass, denser starbursts in low-mass galaxies produce stronger outflows. Our results complement the picture drawn by similar studies at lower redshift, suggesting that the removal of ionized gas in low-mass SFGs driven by stellar feedback is regulated by their stellar mass and by the strength and concentration of their star formation, i.e. ΣSFR\Sigma_{\rm SFR}.Comment: Accepted for publication in A&A. We updated the manuscript following referee's suggestions. We updated the estimations of C/O by not including CIV flux since it is not detected in most of our sample. No major changes in our results compared with previous versio

    Determinants of above-ground carbon stocks and productivity in secondary forests along a 3000-m elevation gradient in the Ecuadorian Andes

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    Background: Secondary montane forests, covering 30% of forested lands in the Andes, play a crucial role in mitigating the impact of carbon release. However, the mechanisms responsible for carbon sequestration in the above-ground biomass of these forests are not well quantified. Aims: Understanding the determinants of above-ground carbon (AGC) dynamics in secondary forests along a 3000-m elevational gradient in the Andes to assess their mitigation potential. Methods: We assessed how abiotic and biotic conditions and past human disturbances were related to forest structure and composition, AGC stocks and productivity within sixteen 0.36-ha plots established in secondary forest stands of 30–35 years of age. Results: Structural equation models revealed that changes in temperature conditions along the elevation gradient shaped leaf functional composition, which in turn controlled AGC dynamics. Productivity and temperature decreased with increasing elevation and decreased tree community leaf area. Disturbance legacy (Tree mortality) increased with competitive thinning and low soil fertility. Conclusions: We show that temperature drives AGC dynamics by changing the functional trait composition. This highlights the importance of preserving these forests along elevation gradients and implies potentially strong future changes due to global warming.</p
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