117 research outputs found
The Strategic Exploitation of Limited Information and Opportunity in Networked Markets
This paper studies the effect of constraining interactions within a market. A model is analysed in which boundedly rational agents trade with and gather information from their neighbours within a trade network. It is demonstrated that a traderâs ability to profit and to identify the equilibrium price is positively correlated with its degree of connectivity within the market. Where traders differ in their number of potential trading partners, well-connected traders are found to benefit from aggressive trading behaviour.Where information propagation is constrained by the topology of the trade network, connectedness affects the nature of the strategies employed
Sildenafil Protects Endothelial Cells From Radiation-Induced Oxidative Stress
Introduction: The etiology of radiation-induced erectile dysfunction (ED) is complex and multifactorial, and it appears to be mainly atherogenic. Aim: To focus on vascular aspects of radiation-induced ED and to elucidate whether the protective effects of sildenafil are mediated by attenuation of oxidative stress and apoptosis in the endothelial cells. Methods: Bovine aortic endothelial cells (BAECs), with or without pretreatment of sildenafil (5 ÎźM at 5 minutes before radiation), were used to test endothelial dysfunction in response to external beam radiation at 10â15 Gy. Generation of reactive oxygen species (ROS) was studied. Extracellular hydrogen peroxide (H2O2) was measured using the Amplex Red assay and intracellular H2O2 using a fluorescent sensor. In addition, ROS superoxide (O2â˘-) was measured using a O2â˘- chemiluminescence enhancer. Both H2O2 and O2â˘- are known to reduce the bioavailability of nitric oxide, which is the most significant chemical mediator of penile erection. Generation of cellular peroxynitrite (ONOOâ) was measured using a chemiluminescence assay with the PNCL probe. Subsequently, we measured the activation of acid sphingomyelinase (ASMase) enzyme by radioenzymatic assay using [14C-methylcholine] sphingomyelin as substrate, and the generation of the proapoptotic C16-ceramide was assessed using the diacylglycerol kinase assay. Endothelial cells apoptosis was measured as a readout of these cellsâ dysfunction. Main Outcome Measures: Single high-dose radiation therapy induced NADPH oxidases (NOXs) activation and ROS generation via the proapoptotic ASMase/ceramide pathway. The radio-protective effect of sildenafil on BAECs was due to inhibition of this pathway. Results: Here, we demonstrate for the first time that radiation activated NOXs and induced generation of ROS in BAECs. In addition, we showed that sildenafil significantly reduced radiation-induced O2â˘- and as a result there was reduction in the generation of peroxynitrite in these cells. Subsequently, sildenafil protected the endothelial cells from radiation therapy-induced apoptosis. Strengths and Limitations: This is the first study demonstrating that single high-dose radiation therapy induced NOXs activation, resulting in the generation of O2â˘- and peroxynitrite in endothelial cells. Sildenafil reduced ROS generation by inhibiting the ASMase/ceramide pathway. These studies should be followed in an animal model of ED. Conclusions: This study demonstrated that sildenafil protects BAECs from radiation-induced oxidative stress by reducing NOX-induced ROS generation, thus resulting in decreased endothelial dysfunction. Therefore, it provides a potential mechanism to better understand the atherogenic etiology of postradiation ED. Wortel RC, Mizrachi A, Li H, et al. Sildenafil Protects Endothelial Cells From Radiation-Induced Oxidative Stress. J Sex Med 2019;16:1721â1733. Š 201
MobilityMirror: Bias-Adjusted Transportation Datasets
We describe customized synthetic datasets for publishing mobility data.
Private companies are providing new transportation modalities, and their data
is of high value for integrative transportation research, policy enforcement,
and public accountability. However, these companies are disincentivized from
sharing data not only to protect the privacy of individuals (drivers and/or
passengers), but also to protect their own competitive advantage. Moreover,
demographic biases arising from how the services are delivered may be amplified
if released data is used in other contexts.
We describe a model and algorithm for releasing origin-destination histograms
that removes selected biases in the data using causality-based methods. We
compute the origin-destination histogram of the original dataset then adjust
the counts to remove undesirable causal relationships that can lead to
discrimination or violate contractual obligations with data owners. We evaluate
the utility of the algorithm on real data from a dockless bike share program in
Seattle and taxi data in New York, and show that these adjusted transportation
datasets can retain utility while removing bias in the underlying data.Comment: Presented at BIDU 2018 workshop and published in Springer
Communications in Computer and Information Science vol 92
Maximum likelihood estimation of linear SISO models subject to missing output data and missing input data
Brokering Trust to Enhance Leadership: A Self-Monitoring Approach to Leadership Emergence
What kind of person is likely to emerge as an informal leader in the workplace? Experimental research shows that high self-monitorsâwho tend to adjust their attitudes and behaviors to the demands of different situationsâemerge as informal leaders in temporary groups. By contrast, low self-monitorsâwho tend to be true to themselves in terms of consistency in attitudes and behaviors across different situationsâare less likely to emerge as leaders. But this prior research does not address the criticism that the emergence of high self-monitors as leaders represents ephemeral impression management in the context of laboratory experiments. To address this issue, we collected and analyzed data from a 116-member high-technology firm. Our results show that self-monitoring is related not only to leadership emergence, but also to the provision of advice to co-workers. Further, people who occupied brokerage positions (being trusted by those who did not trust each other) tended to be seen as leaders if they were high rather than low self-monitors. From these results, we build a picture of the high self-monitoring emergent leader as someone who notices problems and ameliorates them through the provision of advice and the brokerage of relationships across social divides. The occupation of a structurally advantageous position may well be more advantageous for some (i.e., high self-monitors) relative to others (i.e., low self-monitors)
Justice from an interdisciplinary perspective: the impact of the revolution in Human Sciences on Peace Research and International Relations
Peace and justice have been a preferred couple in theoretical writings - but what do we know about their empirical relationship? Insights from other disciplines suggest that humans are highly sensitive to violations of justice and that justice concerns permeate social relations. Neuroscientists have located the parts of the brain responsible for negative reactions to violation of claims for justice. Evolutionary biologists have identified rules of distribution and retribution not only in early human societies but among other socially living species as well. Psychologists have observed the emergence of a sense of justice in very early childhood, while behavioral economists have identified behavior of average persons in experiments that deviated significantly from the model of the "economic man" and could only be explained by a sense of justice. The chapter summarizes these findings and outlines their implications for peace research. It highlights the ambivalent nature of justice for social relations. Justice concerns can exacerbate conflicts between individuals and groups but justice can also provide standards for arriving at durable peaceful solutions to conflicts. Understanding these ambivalences and their repercussions for international and intrastate relations provides a promising path towards understanding conflict dynamics
I know people who can and who cannot: A measure of the perception of economic inequality in everyday life
VersiĂłn preprintThis paper describes the development of the Perceived Economic Inequality in Everyday Life (PEIEL) scale. It is written and validated in Spanish. We first carried out an exploratory study, using a sample of 205 participants (52.2% men and 47.8% women; age: M = 24.69, SD = 8.95). We then conducted a confirmatory study with a sample size of 215 individuals (43.7% men and 56.3% women; age: M = 23.83, SD = 6.46). Results showed that the PEIEL scale is a valid and reliable unidimensional instrument. This scale negatively predicted tolerance of economic inequality over and above perceived inequality measured by wage gap estimates. In addition, perceived economic inequality in everyday life was negatively associated with tolerance of inequality, particularly in individuals with right-wing political ideology.Universidad de Costa Rica/[OAICE-006-2017]/UCR/Costa RicaUCR::Sedes Regionales::Sede de Occident
New Efficient Synthetic Routes to Enantiomerically Pure Fluoroalkyl(Arylsulfinyl)methyl Imines and Amines
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