Black Hole Monodromy and Conformal Field Theory

The analytic structure of solutions to the Klein-Gordon equation in a black hole background, as represented by monodromy data, is intimately related to black hole thermodynamics. It encodes the "hidden conformal symmetry" of a non-extremal black hole, and it explains why features of the inner event horizon appear in scattering data such as greybody factors. This indicates that hidden conformal symmetry is generic within a universality class of black holes.Comment: 20 pages, v2 minor corrections, updated reference

FemtoSats in Zero-G ISS Experiment

The FemtoSats in Zero-G investigation was an ISS experiment in which a handheld deployer ejected four purely mechanical FemtoSats within the ISS. Femto Satellites are centimeter-scale spacecraft that weigh less than 100 grams. The FemtoSats and deployer were made on the Additive Manufacturing Facility (AMF) onboard the ISS on August 28th, 2017, and March 29th, 2017, respectively

Modeling and analysis of a three-species food web with facilitated and intraguild predation

Biotic interactions are known to shape natural community assemblages and biodiversity. Positive interactions such as facilitation have recently received attention in ecological food webs. Mechanistic models have improved our understanding of these complex food web interactions. Here, focus is given to a three-species food web system with a beach dune natural community in mind. In the last decade, there has been a series of studies investigating intraguild predation between two major loggerhead sea turtle nest predators, North American raccoons and Atlantic ghost crabs. Studies have also highlighted that ghost crab predation assists raccoons in finding nests (i.e., facilitated predation). However, the combined effects of these two intraguild interactions and their consequences on nests have not been examined explicitly. The aims of this study were to (i) develop a three-species, ordinary differential equation model (ii) implement a sensitivity analysis to understand the influence of facilitation and other factors in driving species richness and abundance and (iii) characterize the dynamic interactions between intraguild predators and their effects on a shared resource. Interactions between ghost crabs and sea turtle eggs and facilitation can yield a wide variety of species abundance responses and were influential factors in the model. I found that high secondary sea turtle egg depredation and low facilitated predation by raccoons led to three species co-existence regions in the model. Controlling for nest predators at higher abundance levels showed that ghost crabs had a larger negative effect on sea turtle egg abundance responses when compared to raccoons. This suggests that interactions between sea turtle eggs and ghost crabs appear to be important and potential sea turtle nest management implications are discussed such as the use of ghost crab exclusion devices

Phonological but not semantic influences on the speech-to-song illusion

In the speech to song illusion, a spoken phrase begins to sound as if it is being sung after several repetitions. Castro et al. (2018) used Node Structure Theory (NST; MacKay, 1987), a model of speech perception and production, to explain how the illusion occurs. Two experiments further test the mechanisms found in NST—priming, activation, and satiation—as an account of the speech to song illusion. In Experiment 1, words varying in the phonological clustering coefficient influenced how quickly a lexical node could recover from satiation, thereby influencing the song-like ratings to lists of words that were high versus low in phonological clustering coefficient. In Experiment 2, we used equivalence testing (i.e., the TOST procedure) to demonstrate that once lexical nodes are satiated the higher level semantic information associated with the word cannot differentially influence song-like ratings to lists of words varying in emotional arousal. The results of these two experiments further support the NST account of the speech to song illusion

Human fertility after a disaster : a systematic literature review

Fertility is a key demographic parameter influenced by disaster. With the growing risk of disasters, interest in the fertility response to a disaster is increasing among the public, policy makers and researchers alike. As yet, a synthesis of the current evidence on how fertility changes after disaster does not exist. We reviewed 50 studies retrieved from a systematic search based on a pre-registered protocol. We found an overall negative impact of disasters on fertility. If any, increases in fertility were mostly linked with weather-related physical disasters. We also identified 13 distinct mechanisms which researchers have considered as underlying the fertility effects of disaster. By contrast to the common belief that disasters are more likely to increase fertility in contexts with already high fertility, we found little evidence to suggest that the total fertility rate of the studied populations was an important predictor of the direction, timing or size of fertility impacts. While this may be because no relationship exists, it may also be due to biases we observed in the literature towards studying high-income countries or high-cost disasters. We summarize the methodological limitations identified from the reviewed studies into six practical recommendations for future research. Our findings inform both the theories behind the fertility effects of disasters and the methods for studying them

Single motherhood in Ghana: analysis of trends and predictors using demographic and health survey data

The rising rate of single-mother families has gained scholarly and policy attention. Understanding the dynamics in the socio-economic and demographic transformations that have led to the relatively high single-mother families in Ghana is important to advance policy and intervention to mitigate adverse effects of single motherhood. The study sought to examine the trends and predictors of single motherhood in Ghana from 1993 to 2014. This paper was based on data from the last five waves of the Ghana Demographic and Health Survey. Descriptive statistics of proportions with Chi-square test and binary logistic regression were used to assess individual and contextual factors associated with single motherhood in Ghana. The proportion of single motherhood increased significantly over the period from 14.1% in 1993 to 19.5% in 2014. Premarital birth emerged as the major pathway to single motherhood. Among individual factors, the likelihood of single motherhood declines as age at first sex [OR = 0.58; 95% CI = 0.48,0.70] and first birth [OR = 0.43; CI = 0.32,0.59] were 25 years and above. Also, Contraceptive users were less likely to be single mothers than non-users. Contextually, women who profess Islam [OR = 0.58; 95% CI = 0.46, 0.74] were less likely to be single mothers than women who had no religious affiliation. We observed that, after accounting some important factors, women with higher economic status—richer [OR = 0.76; 95% CI = 0.59,0.96] and richest [OR = 0.57; 95% CI = 0.31,0.56] were less likely to be single mothers than poorest women. The findings give an impression of single mothers being over-represented among economically poor women. Policies and programmes meant to mitigate adverse effects of single motherhood should also focus on empowering single mothers and their children as a way of alleviating poverty and improve the well-being of children in this family type, as well as enhance Ghana’s capacity to attain the Sustainable Development Goal 1, particularly target 1.2

Correlación entre Resonancia Magnética y la clasificación del cáncer de recto, según la American Joint Committe on Cancer. Centro Oncológico en Lima Metropolitana.2020

Determina la correlación entre resonancia magnética y la clasificación de cáncer de recto, según la American Joint Committe On Cancer en un hospital oncológico de Lima metropolitana 2020. El estudio es de enfoque cuantitativo, tipo observacional, retrospectivo de corte transversal, con diseño correlacional. Se realizó la revisión de 373 informes de resonancia magnética con resultado histopatológico de pacientes con diagnostico positivo de cáncer de recto, recabando la información de los estadios T y N según la AJCC. Los datos se analizaron mediante el paquete estadístico SPSSv.25, aplicando el coeficiente de correlación Tau-b de Kendall. Por histopatología se encontró en el estadio T una frecuencia de 44.8% en estadio T2, un 41.3% en estadio T3; en el estadio N se encontró una frecuencia de 46.6% en estadio N0, 39.7% en el estadio N1, 13.7% en el estadio N2. En la evaluación por resonancia magnética se encontró en el estadio T una frecuencia de 46.4% en el estadio T3, 42.9% en el estadio T2; en el estadio N se encontró una frecuencia de 46.1% en el estadio N0, 42.9% en el estadio N1 y 11% en el estadio N2. Al evaluar la correlación de la prueba histológica y la de resonancia magnética para el estadio T; se encontró una correlación de 100% en el estadio T4b, un 91.6% en el estadio T3, un 82% en el estadio T2 (b=0.814). Al analizar el estadio N se encontró una correlación de 80.5% en el estadio N0, 78.4% en el estadio N1 y 66.7% en estadio N2 (b=0.669). Existe correlación directa y significativa entre la resonancia magnética y la clasificación de cáncer de recto, según la American Joint Committe On Cancer en un hospital oncológico de Lima metropolitana 2020

CEDR -- A Compiler-integrated, Extensible DSSoC Runtime

In this work, we present CEDR, a Compiler-integrated, Extensible Domain Specific System on Chip Runtime ecosystem to facilitate research towards addressing the challenges of architecture, system software and application development with distinct plug-and-play integration points in a unified compile time and run time workflow. We demonstrate the utility of CEDR on the Xilinx Zynq MPSoC-ZCU102 for evaluating performance of pre-silicon hardware in the trade space of SoC configuration, scheduling policy and workload complexity based on dynamically arriving workload scenarios composed of real-life signal processing applications scaling to thousands of application instances with FFT and matrix multiply accelerators. We provide insights into the trade-offs present in this design space through a number of distinct case studies. CEDR is portable and has been deployed and validated on Odroid-XU3, X86 and Nvidia Jetson Xavier based SoC platforms. Taken together, CEDR is a capable environment for enabling research in exploring the boundaries of productive application development, resource management heuristic development, and hardware configuration analysis for heterogeneous architectures.Comment: 35 pages single column, 16 figures, 7 tables. Accepted for publication in the ACM Transactions on Embedded and Computing System

Uso del modelo Random Forest mediante Google Earth Engine para determinar el cambio de área de los ecosistemas y su relación con el cambio climático en la cuenca Sibinacocha, 1984 – 2020

El presente estudio se desarrolla en la Cuenca Sibinacocha la cual tiene un área de 134.45 km2 y se ubica en la Cordillera Vilcanota al Sur del Perú, donde se ha observado el retroceso glaciar y la alteración del paisaje, por lo cual se planteó como objetivo principal analizar los cambios anuales del área de los ecosistemas y su relación con el cambio climático en el periodo entre 1984 al 2020. El área de los ecosistemas (Glaciar, Cuerpos de Agua, Humedales, Pastizales, y Escasa Vegetación) de la cuenca, fue obtenida aplicando el modelo Random Forest mediante Google Earth Engine. La serie temporal de datos de Precipitación y Temperatura (máxima, media y mínima) se obtuvieron a partir del modelo climático WRF (Weather Research and Forecast). Los registros fueron analizados en dos periodos de estudio, anual y estacional (abril a agosto), para determinar la influencia del clima sobre los ecosistemas, mediante análisis estadísticos de correlación y modelos de regresión lineal simple. La reducción de la cobertura glaciar está principalmente relacionada al incremento de la temperatura mínima anual, generando nuevos cuerpos de agua por escorrentía y la aparición de nuevas zonas de escasa vegetación que aparecen en zonas cercanas a los glaciares. El desarrollo de los humedales y los pastizales, presentan una relación entre sí, debido a la competencia por territorio. El cambio de los glaciares en la Cuenca Sibinacocha, representa un eje importante para la evolución de los ecosistemas de alta montaña de la zona.Tesis financiada por el Fondo Newton-Paulet-Embajada Britanica-Concyte

Food Security Network Modeling

Food security creates a complex issue for American interests. Within a constantly expanding operational environment, food security remains a vital lifeline both domestically and abroad.  Current methods of mapping an area’s food system rely on ad-hoc assessments that produce skewed results and minimal metric analysis. Previous assessments methodologies failed to incorporate components of a food system that influences the overall stability of an area. The research conducted utilized the Systems Decision Process (SDP) to create a value hierarchy and model that provide an assessment for an areas food system. The findings from the research showcase that a food system relies on several variables such as infrastructure, dietary needs, and the national stability of a region. A more enhanced assessment model was developed that placed an overarching value to a food network that allows ground commanders to gain a holistic overview of the condition of an areas food system