Aerosol and Precipitation Chemistry Relationships in Arizona during the Monsoon Season

This study identified the relationships between aerosol and precipitation chemistry during the monsoon season (June 15- September 15) in Arizona by using four co-located IMPROVE and NADP NTN sites: Chiricahua National Monument (Chir NM), Grand Canyon, Organ Pipe National Monument (Organ Pipe NM), and Petrified National Park (Petrified NP). Relationships between 1999 and 2014 were determined by using the using a two-tailed student’s t-test (95% confidence). In Chir NM and Grand Canyon, decreasing significant annual trends of sulfate aerosol fractions coincided with increasing significant annual trends of rain pH. This result suggests that in Chir NM and Grand Canyon, the decrease in sulfate aerosol concentrations result in more alkaline pH. Aerosol and rain interrelationships in all sites showed that calcium (Ca), magnesium (Mg), and potassium (K) were highly related to each other suggesting their origin from common dust sources. Similarly based on these interrelationships, sodium (Na) and chloride (Cl-) were related to sea salt in all sites. At all sites, the highest correlation values between aerosol and precipitation concentration correlations were found for Ca, K, Mg, and Na (in decreasing order), suggesting the role of dust and sea salt as cloud condensation nuclei (CCN) or ice nuclei (IN). The highest grand average of rain accumulation was found in Chir NM and this coincided with the most acidic pH and lowest rain concentrations. In Chir NM, the highest mass fractions and amount of moles in rain of Sulfate and Nitrate were found which justify the acidic pH. The opposite trends are found in Petrified NP, which has the lowest grand annual average of rain accumulation, most alkaline pH, highest rain concentrations, and lowest mass fractions and moles in rain of nitrate and sulfate. The use of rain concentrations are misleading due to the dilution of rain which does not provide information on the absolute amount and abundance of certain ions. Hence it is necessary to analyze the amount of moles and mass fractions in rain of acidic anions to determine the effect on rain pH. At all sites, the significant correlations between rain accumulation and aerosol and rain concentrations were negative, suggesting that the monsoon rain acts as a sink. However, the significant correlations between rain accumulation and amount of moles in rain were positive for all species in all sites. The positive relationships are justified by the uptake of aerosol concentrations by rain by cloud seeding and scavenging. Of these relationships, sulfate and nitrate exhibited the highest correlated values (r-values) where sulfate and nitrate gaseous precursors are capable of directly entering rain drops. Inverse relationships between air and rain mass fractions of nitrate were found with respect to pH where nitrate was more alkaline in the air and more acidic in the rain. The result suggests that in the air, precursor forms of nitrate which can react with dust emissions are found, and the product of this reaction (highly water soluble) serves as cloud condensation nuclei where the presence of nitrate in rain is acidic. In addition, the slope of the correlation value for air or rain mass fraction can be used as a proxy to determine whether it is acidic or alkaline. Acidic mass fractions would exhibit positive values with respect to sulfate air mass fractions and rain accumulation and negative values for all other aerosol and precipitation data. To determine the effects of moisture source on aerosol and precipitation chemistry, it was necessary to choose one site that had sources of moisture from the Gulf of California and compare this to another site that had moisture sources from the Gulf of Mexico. The Kruskal Wallis test was applied to aerosol concentrations to determine if sites shared similar air mass sources. The results of this test indicate that Chir NM, Grand Canyon, and Petrified NP share similar air mass sources while Organ Pipe NM did not share any similarities. Next, based on these results and previous studies, Chir NM and Organ Pipe NM were chosen to determine the effects of air mass source on the aerosol and precipitation chemistry. Air mass back trajectories revealed that Chir NM and Organ Pipe NM shared similar moisture sources from the Gulf of California and few dates were found where they differed. Future work will seek to compare sites in western Arizona (Organ Pipe NM) to other co-located NADP and IMPROVE sites in New Mexico. The results of this work suggest that the reactions between dust and precursors of nitrate and sulfate are commonly found in Arizona. During the monsoon period, higher rain accumulation is observed which uptakes more dust containing acidic ions and acidic precursor gases via scavenging, resulting in increasingly acidic rain pH. Therefore, the aquatic and terrestrial ecosystems found in the area are exposed to acidic rain during the monsoon season. However, in 1999 to 2014, the reduction of sulfate aerosol concentrations due to air regulations has possibly led to an increase in alkalinity of rain pH

Plantear el uso de prácticas de seguridad en las TIC's en la Institución Educativa Mater Dei de la ciudad Medellín

Este proyecto contiene en su primer capítulo el anteproyecto realizado sobre el tema de investigación de Plantear el uso de prácticas de seguridad en las TIC’S en la institución educativa Mater Dei de la ciudad de Medellín. También presenta el diseño metodológico donde se establece la forma en que fue realizada la investigación por los integrantes del equipo del proyecto, definiendo los métodos utilizados, las técnicas y herramientas empleadas y los pasos que se siguieron para el análisis de cada uno de los estudios. En el tercer capítulo se presentan todos los hallazgos investigativos, el cual contempla el desarrollo de cada uno de los estudios realizados, a saber: estudio de actores, estudio de lógicas colectivas, estudio jurídico, estudio del entorno, estudio técnico, estudio económico, estudio de impacto socio económico y estudio gerencial; los cuales fueron la base de análisis del proyecto presentado

Plantear el uso de prácticas de seguridad en las TIC's en la Institución Educativa Mater Dei de la ciudad Medellín

Este proyecto contiene en su primer capítulo el anteproyecto realizado sobre el tema de investigación de Plantear el uso de prácticas de seguridad en las TIC’S en la institución educativa Mater Dei de la ciudad de Medellín. También presenta el diseño metodológico donde se establece la forma en que fue realizada la investigación por los integrantes del equipo del proyecto, definiendo los métodos utilizados, las técnicas y herramientas empleadas y los pasos que se siguieron para el análisis de cada uno de los estudios. En el tercer capítulo se presentan todos los hallazgos investigativos, el cual contempla el desarrollo de cada uno de los estudios realizados, a saber: estudio de actores, estudio de lógicas colectivas, estudio jurídico, estudio del entorno, estudio técnico, estudio económico, estudio de impacto socio económico y estudio gerencial; los cuales fueron la base de análisis del proyecto presentado

IMPLEMENTACIÓN EN FPGA DE UN CLASIFICADOR DE MOVIMIENTOS DE LA MANO USANDO SEÑALES EMG

Este trabajo presenta el diseño e implementación de un clasificador de señales electromiográficas (EMG) para tres movimientos de la mano: flexión, extensión y cierre, usando dos músculos del antebrazo, palmar largo y extensor común de los dedos. El desarrollo comprende dos bloques principales, el hardware para la adquisición y adecuación de la señales EMG analógicas y el sistema de procesamiento para la identificación y clasificación del movimiento realizado; el sistema completo fue implementado en hardware usando un kit de desarrollo DE2-70 que cuenta con un FPGA Cyclone II de Altera. Para la extracción de características se implementó la Transformada Rápida de Fourier (FFT), para cada canal, a la cual se le calcularon  técnicas de procesamiento  como la varianza y el promedio.. Finalmente, se establece un umbral de decisión para identificar el movimiento realizado. El tiempo de respuesta del sistema total fue de 17,7 us, obteniendo una tasa de identificación mayor al 87%.FPGA implementation of a hand motions classifier using EMG signalsAbstractThis paper presents the design and implementation of a hand motions classifier using electromyographic (EMG) signals. The classified motions are: wrist flexion, wrist extension and hand closure. The motions are classified using two forearm muscles: longus palmar and extensor digitorum. This work was implemented in two principal blocks: the acquisition and adequacy of the EMG signal, and the processing system for the identification and classification of the motion made. The processing system was implemented on hardware using a development kit with a Cyclone II FPGA from Altera. For the feature extraction the Fast Fourier Transform (FFT) is performed at each channel and some features like variance and mean are calculated. Finally, a threshold decision block is used to identify the motion. The system have a time response of 17,7 us, obtaining an identification rate higher than 87%.Keywords: EMG signals, FPGA, motion classifier, real time

Unsupervised cell segmentation and labelling in neural tissue images

Neurodegenerative diseases are a group of largely incurable disorders characterised by the progressive loss of neurons and for which often the molecular mechanisms are poorly understood. To bridge this gap, researchers employ a range of techniques. A very prominent and useful technique adopted across many different fields is imaging and the analysis of histopathological and fluorescent label tissue samples. Although image acquisition has been efficiently automated recently, automated analysis still presents a bottleneck. Although various methods have been developed to automate this task, they tend to make use of single-purpose machine learning models that require extensive training, imposing a significant workload on the experts and introducing variability in the analysis. Moreover, these methods are impractical to audit and adapt, as their internal parameters are difficult to interpret and change. Here, we present a novel unsupervised automated schema for object segmentation of images, exemplified on a dataset of tissue images. Our schema does not require training data, can be fully audited and is based on a series of understandable biological decisions. In order to evaluate and validate our schema, we compared it with a state-of-the-art automated segmentation method for post-mortem tissues of ALS patients

Burnout Among First-Year Medical Students During COVID-19 Pandemic in Mexico: A Cross-Sectional Study

Background: The coronavirus pandemic is an international public health emergency without precedence in modern history. It represents a challenge to students’ academic and psychological stability due to the changes it caused in daily life. This study aimed to evaluate the prevalence and level of burnout in medical students caused by the academic and psychological instability that the pandemic represents. Methods: A prospective cross-sectional study was designed using the Maslach Burnout Inventory-Student Survey (MBI-SS). This evaluated the emotional exhaustion due to study demands, cynicism, and negative self-academic efficacy. This study was based in the school of medicine of the Universidad Autonoma de Nuevo Leon (UANL) in Monterrey, Mexico, during the Spring semester of 2020. Results: A total of 154 (93 women and 61 men) first-year medical students participated (response rate of 36.4%). Burnout was identified in 14.9% (n=23), and high emotional exhaustion in 53.9% (n=83). Burnout was almost 4 times more likely to develop in men than in women (aOR = 4.8; 95% Confidence Interval=1.7-13.3) when considering age as a covariable in the multivariable model. Conclusion: Further epidemiological studies of burnout syndrome in medical students are needed, and schools should consider promoting mental health and making programs available for their students to help overcome the emotional and social challenges during the pandemic

Tetrahedral (T) closed-shell cluster of 29 silver atoms & 12 lipoate ligands, [Ag29(R-a-LA)12](3-): antibacterial and antifungal activity

Accepted author manuscriptHere we report on the identification and applications of an aqueous 29-atom silver cluster stabilized with 12 lipoate ligands, i.e. Ag29(R-α–LA)12 or (29,12), wherein R-α–LA = R-α-lipoic acid, a natural dithiolate. Its uniformity is checked by HPLC-ESI-MS and analytical ultracentrifugation, which confirms its small dimension (∼3 nm hydrodynamic diameter). For the first time, this cluster has been detected intact via electrospray ionization mass spectrometry, allowing one to confirm its composition, its [3-] charge-state, and the 8-electron shell configuration of its metallic silver core. Its electronic structure and bonding, including T-symmetry and profound chirality in the outer shell, have been analyzed by DFT quantum-chemical calculations, starting from the known structure of a nonaqueous homologue. The cluster is effective against Methicillin-Resistant Staphylococcus aureus bacteria (MRSA) at a minimum inhibitory concentration (MIC) of 0.6 mg-Ag/mL. A preformed Candida albicans fungal biofilm, impermeable to other antifungal agents, was also inhibited by aqueous solutions of this cluster, in a dose–response manner, with a half-maximal inhibitory concentration (IC50) of 0.94 mg-Ag/mL. Scanning electron micrographs showed the post-treatment ultrastructural changes on both MRSA and C. albicans that are characteristic of those displayed after treatment by larger silver nanoparticles.Ye

Expansion of Signal Transduction Pathways in Fungi by Extensive Genome Duplication

International audienceno abstrac

Consensus Recommendation for Mouse Models of Ocular Hypertension to Study Aqueous Humor Outflow and Its Mechanisms.

Due to their similarities in anatomy, physiology, and pharmacology to humans, mice are a valuable model system to study the generation and mechanisms modulating conventional outflow resistance and thus intraocular pressure. In addition, mouse models are critical for understanding the complex nature of conventional outflow homeostasis and dysfunction that results in ocular hypertension. In this review, we describe a set of minimum acceptable standards for developing, characterizing, and utilizing mouse models of open-angle ocular hypertension. We expect that this set of standard practices will increase scientific rigor when using mouse models and will better enable researchers to replicate and build upon previous findings

Juxtaposing BTE and ATE – on the role of the European insurance industry in funding civil litigation

One of the ways in which legal services are financed, and indeed shaped, is through private insurance arrangement. Two contrasting types of legal expenses insurance contracts (LEI) seem to dominate in Europe: before the event (BTE) and after the event (ATE) legal expenses insurance. Notwithstanding institutional differences between different legal systems, BTE and ATE insurance arrangements may be instrumental if government policy is geared towards strengthening a market-oriented system of financing access to justice for individuals and business. At the same time, emphasizing the role of a private industry as a keeper of the gates to justice raises issues of accountability and transparency, not readily reconcilable with demands of competition. Moreover, multiple actors (clients, lawyers, courts, insurers) are involved, causing behavioural dynamics which are not easily predicted or influenced. Against this background, this paper looks into BTE and ATE arrangements by analysing the particularities of BTE and ATE arrangements currently available in some European jurisdictions and by painting a picture of their respective markets and legal contexts. This allows for some reflection on the performance of BTE and ATE providers as both financiers and keepers. Two issues emerge from the analysis that are worthy of some further reflection. Firstly, there is the problematic long-term sustainability of some ATE products. Secondly, the challenges faced by policymakers that would like to nudge consumers into voluntarily taking out BTE LEI