1,930 research outputs found
Is the revolving door of Washington a back door to excess corporate returns?
In this paper, we look into the so-called "revolving door of Washington", which is the movement of individuals between federal government positions and jobs in the private sector, and examine its link to long-run stock returns. We find that firms where current public officials become future employees outperform other firms by a statistically significant 7.43% per year in terms of four-factor alpha. This result is robust to different weighting methodologies and risk adjustments, and to plausible reverse causality arguments. We also show that firms receive more valuable government contracts from a government agency when a future firm employee is holding a post at that agency. Such financial gains are significantly reduced during periods in which presidential executive orders restrict revolving door movements. Our results are consistent with the notion that some public officials could be favoring certain companies while in office with a view to gaining future corporate employment
The Effect of City Conditions on Youth Violence in Mexico A Spatial Econometric Analysis by Metropolitan Area
Using Mexico s Social Cohesion Survey for the Prevention of Violence and Crime ECOPRED 2014 and the Mexican Intercensal Population Survey CONTEO 2015 this paper analyses the characteristics and environment factors that influence the violent behavior of young people aged 14 to 24 years within the 47 largest Mexican cities The existence of spatial correlation between Mexican cities is corroborated and after controlling for it it is found that factors related to addictions drug use by young people and their families and a violent environment around the young being bullied robbed or having violent friends neighbors coworkers or classmates are positively related to the percentage of young people who shout hit objects hit people carry weapons or have been arrested Public policies to reduce the use of drugs and to improve the environment where young people live mainly in their neighborhoods schools and jobs will have a direct effect on reducing the violent behavior of young people And given the confirmed existence of spatial effects coordinated efforts between nearby cities could multiply the impact of such public policie
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“TELE-commuting” During the COVID-19 Pandemic and Beyond: Unveiling State-wide Patterns and Trends of Telecommuting in Relation to Transportation, Employment, Land Use, and Emissions in Calif
Telecommuting, the practice of working remotely at home, increased significantly (25% to 35%) early in the COVID-19 pandemic. This shift represented a major societal change that reshaped the family, work, and social lives of many Californians. These changes also raise important questions about what factors influenced telecommuting before, during, and after COVID-19, and to what extent changes in telecommuting have influenced transportation patterns across commute modes, employment, land use, and environment. The research team conducted state-level telecommuting surveys using a crowd-sourced platform (i.e., Amazon Mechanical Turk) to obtain valid samples across California (n=1,985) and conducted state-level interviews among stakeholders (n=28) across ten major industries in California. The study leveraged secondary datasets and developed regression and time-series models. Our surveys found that, compared to pre-pandemic levels, more people had a dedicated workspace at home and had received adequate training and support for telecommuting, became more flexible to choose their own schedules, and had improved their working performance—but felt isolated and found it difficult to separate home and work life. Our interviews suggested that telecommuting policies were not commonly designed and implemented until COVID-19. Additionally, regression analyses showed that telecommuting practices have been influenced by COVID-19 related policies, public risk perception, home prices, broadband rates, and government employment. This study reveals advantages and disadvantages of telecommuting and unveils the complex relationships among the COVID-19 outbreak, transportation systems, employment, land use, and emissions as well as public risk perception and economic factors. The study informs statewide and regional policies to adapt to the new patterns of telecommuting
Experimental Validation of a Numerical Forward Model for Tunnel Detection Using Cross-Borehole Radar
The goal of this research is to develop an experimentally validated twodimensional (2D) finite difference frequency domain (FDFD) numerical forward model to study the potential of radar-based tunnel detection. Tunnel detection has become a subject of interest to the nation due to the use of tunnels by illegal immigrants, smugglers, prisoners, assailants, and terrorists. These concerns call for research to nondestructively detect, localize, and monitor tunnels. Nondestructive detection requires robust image reconstruction and inverse models, which in turn need robust forward models. Cross-Well Radar (CWR) modality is used for experimentation to avoid soil-air interface roughness. CWR is not a versatile field technology for political boundaries but is still applicable to monitoring the perimeter of buildings or secure sites. Multiple-depth wideband frequency-response measurements are experimentally collected in fully water-saturated sand, across PVC-cased ferrite-bead-jacketed borehole monopole antennae at a pilot scale facility (referred to as SoilBED). The experimental results are then compared with the 2D-FDFD model. The agreement between the results of the numerical and experimental simulations is then evaluated. Results of this work provide key diagnostic tools that can help to develop the algorithms needed for the detection of underground tunnels using radar-based methods
Assessing Distribution Network Flexibility via Reliability-based P-Q Area Segmentation
This paper proposes a framework to assess the flexibility of active
distribution networks (ADNs) via P-Q area segmentation, considering the
reliability of flexible units (FUs). A mixed-integer quadratically constrained
programming (MIQCP) model is formulated to analyse flexible active and reactive
power support at the interface with transmission networks, explicitly capturing
the contributions and reliability of FUs that provide flexibility services
within an ADN. The numerical simulations performed for a real 124-bus UK
distribution network demonstrate the optimal flexibility provision by different
FUs, as well as the corresponding reliability and the impact of network
reconfiguration. Distribution system operators (DSOs) can use the proposed
framework to identify critical units, select an adequate combination of
flexibility volumes, and manage its reliability.Comment: Submitted to PSCC 2022, then resubmitted to IEEE PowerTech 2023
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Transcriptome changes in grapevine (Vitis vinifera L.) cv. Malbec leaves induced by ultraviolet-B radiation
<p>Abstract</p> <p>Background</p> <p>Ultraviolet-B radiation (UV-B, 280-315 nm) is a natural component of sunlight, which has numerous regulatory effects on plant physiology. The nature of the response to UV-B is dependent on fluence rate, dose, duration and wavelength of the UV-B treatment. Some reports have analyzed the changes in gene expression caused by UV-B light on several plant species using microarray technology. However, there is no information on the transcriptome response triggered by UV-B in grapevine. In this paper we investigate the gene expression responses of leaves from <it>in vitro </it>cultured <it>Vitis vinifera </it>cv. Malbec plants subjected to the same dose of biologically effective UV-B radiation (4.75 kJ m<sup>-2 </sup>d<sup>-1</sup>) administered at two different fluence rates (16 h at ≅ 8.25 μW cm<sup>-2</sup>, 4 h at ≅ 33 μW cm<sup>-2</sup>) using a new custom made GrapeGen Affymetrix GeneChip<sup>®</sup>.</p> <p>Results</p> <p>The number of genes modulated by high fluence rate UV-B doubled the number of genes modulated by low fluence UV-B. Their functional analyses revealed several functional categories commonly regulated by both UV-B treatments as well as categories more specifically modulated depending on UV-B fluence rate. General protective responses, namely the induction of pathways regulating synthesis of UV-B absorbing compounds such as the Phenylpropanoid pathway, the induction of different antioxidant defense systems and the activation of pathways commonly associated with pathogen defense and abiotic stress responses seem to play critical roles in grapevine responses against UV-B radiation. Furthermore, high fluence rate UV-B seemed to specifically modulate additional pathways and processes in order to protect grapevine plantlets against UV-B-induced oxidative stress, stop the cell cycle progression, and control protein degradation. On the other hand, low fluence rate UV-B regulated the expression of specific responses in the metabolism of auxin and abscisic acid as well as in the modification of cell walls that could be involved in UV-B acclimation-like processes.</p> <p>Conclusion</p> <p>Our results show the UV-B radiation effects on the leaf transcriptome of grapevine (<it>Vitis vinifera </it>cv. Malbec) plantlets. Functional categories commonly modulated under both UV-B treatments as well as transcripts specifically regulated in an UV-B-intensity dependent way were identified. While high fluence rate UV-B had regulatory effects mainly on defense or general multiple-stress responses pathways, low fluence rate UV-B promoted the expression of genes that could be involved in UV-B protection or the amelioration of the UV-B-induced damage. This study also provides an extensive list of genes regulating multiple metabolic pathways involved in the response of grapevine to UV-B that can be used for future researches.</p
ENTORNOS PARA EL DESARROLLO DE APLICACIONES MÓVILES
El esquema de desarrollo de las aplicaciones móviles es una tecnología que se encuentra en auge, aun cuando los dispositivos móviles existen desde hace más de 15 años, la perspectiva de los visionarios de las tecnologías de la información, y la disminución de costos de fabricación, ha permitido que tales dispositivos estén al alcance de los usuarios. Aun cuando parte de la teoría para el desarrollo de aplicaciones de esta tipo ya se encuentra plasmada en diversos documentos, se considera relevante plantear los nuevos usos que pueden darse a esta tecnología; lo anterior derivado por los avances tecnológicos: características, rendimiento, esquemas de comunicación, sistemas operativos, lenguajes de programación, almacenamiento y recuperación de datos, entre otras
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