Estimating the transition matrix of a Markov chain observed at random times

In this paper we develop a statistical estimation technique to recover the transition kernel $P$ of a Markov chain $X=(X_m)_{m \in \mathbb N}$ in presence of censored data. We consider the situation where only a sub-sequence of $X$ is available and the time gaps between the observations are iid random variables. Under the assumption that neither the time gaps nor their distribution are known, we provide an estimation method which applies when some transitions in the initial Markov chain $X$ are known to be unfeasible. A consistent estimator of $P$ is derived in closed form as a solution of a minimization problem. The asymptotic performance of the estimator is then discussed in theory and through numerical simulations

Water Politics: Governance, Conflict, and Vulnerability in Andean Peru

Peru is facing serious social and environmental water challenges. Experts and policy makers are trying to better understand the social and economic impacts of an increasing rate of glacial melt and a consequential prospect of water scarcity. Currently there is a great deal of strain put on the water resources originating from Andean glacial melt because these sustain most economic and social growth taking place at the coastal desert. At the same time, the country\u27s neoliberal development policies are changing the management of resources such as water. The gradual expansion of extractive industries along with the growing influence of non-state actors is introducing new discursive representations of the environment and facilitating important changes in the spatial, administrative, and political relations of governing nature. Among the most prominent changes are the recent restructuring efforts to the Peruvian institutional and legal structure for water governance. In this context, the forms of access, control, and exploitation of water in the Andes have become more contested than ever. This thesis explores the struggle for water at Parón, one of such Andean communities. This decade-long struggle for water perfectly demonstrates how local groups, government agencies, and a private corporation negotiate their access to water. This thesis explores how organizational structures, institutional arrangements, and decision-making processes shape and are shaped by access, use, management, and regulation of water in a conflictive environment. Particularly, it analyzes how politics informs water management, and consequentially affects access to the resource. But also, given the uniqueness of this conflict, this thesis further incorporates a risk and vulnerability factor to its analysis. While this conflict comprises the socioeconomic, political, historical, cultural, and environmental components of most environmental struggles in Peru, it also presents very unique characteristics. The contested water source is managed not only for downstream water use, but also for glacial risk mitigation. As such, this thesis examines how water governance and vulnerability are co-produced in a conflictive environment. For this, I explore specific moments or instances - such as water flows and management, technology, institutions, discourses, and negotiations - that I recognize as embodying this relationship. In this analysis, I pay special attention to the impact of water technologies. I argue that a new, more convoluted, form of water politics - introduced to the watershed with hydropower technology - have created a new set of social relations that reinforce social vulnerability upon local water users, producing a transformation in vulnerability

Analysis of gender and gender-related implicit leadership themes in HR practitioner literature : a comparison of the United States and Brazilian HR practitioner publications.

Among the many factors studied in relation to the women and leadership equality gap are gender stereotypes, implicit leadership theories, and the congruity of gender role expectations (Eagly, & Karau, 2002). Multiple studies in the scholarly literature support the finding that men, rather than women, are more likely to be seen as leaders (Bierma, 2016; Eagly, & Schmidt, 2001), and this finding appears to be robust across some cultures (Schein, 2001). While the scholarly research on women and leadership has been burgeoning, few research studies have investigated how human resource (HR) practitioner literature addresses themes related to women and leadership (Hanscome, & Cervero, 2003). Human Resource processes and practitioner decisions relating to selection and promotion, development opportunities, compensation, performance management, and other employment conditions affect women’s and men’s careers. Likewise, investigating practitioner literature in the United States (U.S.), as well as other countries is a worthwhile endeavor to gain an understanding of themes relating to women and leadership cross-culturally. The purpose of this content analysis study is to investigate themes relating to women and leadership in HR practitioner literature found in the U.S. and Brazil, which has the second largest economy in the Western hemisphere. Findings and implications are explored based on scholarly literature on women and leadership and culture, and themes pertaining to implicit leadership theories and gender stereotypes, role congruity, power relations, and intersectionality

The chemokine CXCL16 modulates neurotransmitter release in hippocampal CA1 area.

Chemokines have several physio-pathological roles in the brain. Among them, the modulation of synaptic contacts and neurotransmission recently emerged as crucial activities during brain development, in adulthood, upon neuroinflammation and neurodegenerative diseases. CXCL16 is a chemokine normally expressed in the brain, where it exerts neuroprotective activity against glutamate-induced damages through cross communication with astrocytes and the involvement of the adenosine receptor type 3 (A3R) and the chemokine CCL2. Here we demonstrated for the first time that CXCL16 exerts a modulatory activity on inhibitory and excitatory synaptic transmission in CA1 area. We found that CXCL16 increases the frequency of the miniature inhibitory synaptic currents (mIPSCs) and the paired-pulse ratio (PPR) of evoked IPSCs(eIPSCs), suggesting a presynaptic modulation of the probability of GABA release. In addition, CXCL16 increases the frequency of the miniature excitatory synaptic currents (mEPSCs) and reduces the PPR of evoked excitatory transmission, indicating that the chemokine also modulates and enhances the release of glutamate. These effects were not present in the A3RKO mice and in WT slices treated with minocycline, confirming the involvement of A3 receptors and introducing microglial cells as key mediators of the modulatory activity of CXCL16 on neurons

Evaluación de densidades de tres híbridos de maíz, con antecesores diferentes y distintos niveles de fertilización

Trabajo final integrador. (Area de Consolidación Métodos Cuantitativos para la Investigación Agropecuaria)--UNC- Facultad de Ciencias Agropecuarias, 2015.El objetivo del presente trabajo es evaluar el comportamiento de tres híbridos de maíz ante variaciones en la densidad poblacional del cultivo y la nutrición nitrogenada, considerando a dos posibles cultivos antecesores. El ensayo se llevó a cabo en la localidad de Colonia Marina, al Este de la provincia de Córdoba, trabajando en macro parcelas con un diseño de bloques al azar con 72 tratamientos dónde se evalúan 3 híbridos (510PW, 505PW y 562PW), 4 densidades de siembra (45.000, 55.000, 69.000 y 82.000 pl. /ha) y 3 niveles de nutrición nitrogenada (0 kg/ha de N2, 32 kg/ha N2 y 64 kg/ha N2), considerando la alternativa de tener dos cultivos diferentes como antecesor (Trigo y Soja). Cada parcela consto de 8 surcos a 52.5 cm por cada densidad analizada y presentando un largo de 200 metros, obteniendo por cada parcela una superficie de 840 m2. Con la estadística descriptiva se observó que, cuando no se fertiliza, el que mejor repuesta tiene es el hibrido 510PW a mayor densidad de siembra con antecesor soja. Cuando se eleva la fertilización a 32 kg/ha de N2 se ve respuestas en su rendimiento promedio de todos los híbridos a menores densidades de siembra en ambos antecesores. Cuando la fertilización fue de 64 kg/ha N2 en todos los híbridos se ve el aumento del rendimiento promedio. Luego de realizar la estadística descriptiva para cada híbrido, y a los fines de tomar una decisión respecto a la densidad del híbrido que mejor desempeño tiene en la zona, evaluándolos con un modelo estadístico eficiente, es decir el que menor error experimental tenga, se optó por hacer el análisis de los datos separándolos por cultivo antecesor (Trigo y Soja). Debido a que en el modelo del ANAVA se detectó falta de homogeneidad de varianzas entre los híbridos, se ajustó para los distintos cultivos antecesores (soja y trigo), mediante modelos Lineales generales y mixtos. Si bien se observan diferencias en los distintos híbridos recomendados para la zona, en el presente trabajo se llegó a la conclusión que la conjunción de una buena genética con prácticas de manejo sustentables (uso de distintos cultivos antecesores), define el rendimiento objetivo del cultivo de maíz. En lo que respecta a la elección de densidad de siembra, la decisión debe recaer en aquel manejo que garantice el mejor uso de los recursos ambientales disponibles (agua, luz y nutrientes) y genere el menor costos en uso de semillas, a lo que se refiere a la fertilización deberá ser aquella que cumpla con los requerimientos del cultivo para que este exprese su máximo potencial, ya que no se aprecia una interacción entre las densidades de siembra y las dosis de fertilización aplicadas

Genetic Characterization of a Pigeon Paramyxovirus Type 1 Isolated from Columba livia in Uruguay

The isolation and molecular characterization of pigeon paramyxovirus type 1 (PPMV-1) from a sick racing pigeon in Uruguay is reported for the first time. Hemagglutination inhibition (HI) tests were performed to detect antibodies against avian paramyxovirus serotype 1 (APMV-1), and a HI titer of 1/32 was obtained. Tracheal and cloacal swabs were processed by real-time reverse transcriptionpolymerase chain reaction (rRT-PCR) with the use of the National Veterinary Services LaboratoryU.S. Department of Agriculture validated matrix (M) gene assay and were positive for APMV-1. Viral isolation in embryonated chicken eggs confirmed the molecular detection of the isolate. A fragment corresponding to the 3' region of the fusion (F) protein gene was amplified by RT-PCR, and subsequently sequenced. The deduced amino acid sequence at the F protein cleavage site displayed the motif 112RRQKR/F 117. Phylogenetic analysis of this part of the genome allowed the isolated virus to be grouped in the lineage VIb/4b, which suggests that it shares the same ecologic niche with other PPMV-1 that were found in the region, and it is not imported as other European or North American viruses.Fil: Castro, E. R.. No especifíca;Fil: Zanetti, Flavia Adriana. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Biotecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Arbiza, Juan. Universidad de la Republica; Urugua

Targeting pituitary adenylate cyclase-activating polypeptide (PACAP) with monoclonal antibodies in migraine prevention: a brief review

Introduction Interest is growing in the role of pituitary adenylate cyclase-activating polypeptide (PACAP) and its specific PAC1 receptor in migraine and in their antagonism as a strategy for migraine prevention. Areas covered We discuss and critically evaluate (i) the evidence of the role of PACAP in migraine pathophysiology and (ii) the first clinical trials in migraine prophylaxis with monoclonal antibodies AMG 301 and ALD1910 which act against PAC1 and PACAP38 respectively. We examined PubMed, Scopus, and ClinicalTrials.gov electronic databases to examine the relevant material. Expert opinion There is much proof of the ability of PACAP to cause migraine, but there is limited evidence that blocking PACAP or PAC1 receptor can prevent migraine. However, the potential of anti-PACAP antibodies in migraine prophylaxis is high. Theoretically, if these antibodies block the activation of the trigeminovascular system, they will prevent the onset of migraine attacks. There are still knowledge gaps in the role of PACAP in migraine and the risk/benefit ratio of anti-PACAP antibodies must be carefully studied

Ferramentas tecnológicas ajudaram a sociedade civil brasileira no trabalho com migrantes durante a pandemia, mas não substituem transformações duradouras

Organizações da sociedade civil ofereceram apoio vital a populações migrantes e refugiadas no Brasil durante a crise do COVID-19. Muitas delas foram forçadas a adaptar seus programas a fim de lidar com a crescente demanda por ajuda emergencial, com a expansão do uso das tecnologias permitindo um novo modelo híbrido de trabalho. Porém, mesmo com todos os problemas que ajuda a solucionar, a tecnologia também pode levantar novas questões e, em última análise, não deve ser vista como substituto para soluções duráveis, escrevem Marcia Vera Espinoza (Queen Mary University of London), Gisela P. Zapata (Universidade Federal de Minas Gerais) e Flavia R. Castro (PUC-Rio)

Precision en la medicion del peso fetal por ultrasonido en embarazos a terminos en el servicio de ginecologia del hospital bautista en el periodo de julio a octubre de 2011

Tesis (Doctor en Medicina y Cirugia)--Universidad Americana, Managua, 2012Este estudio pretende buscar si existe diferencia entre el Peso fetal encontrado por el Ultrasonido y el Peso real del producto al nacer con el fin de definir si estos datos se encuentran dentro del rango aceptable de margen de error. Esto para verificar si se están evitando complicaciones obstétricas de manera adecuada y tomando decisiones acertadas en base al peso en el período comprendido entre julio y octubre de 2011 en el Servicio de Ginecología del Hospital Bautista

Evaluación del potencial efecto neuroprotector de macamidas sintéticas en la reducción de daño cerebral, conservación de la respuesta sensorio - motora y alivio del deterioro de memoria y aprendizaje espacial causados por isquemia cerebral focal en ratas, Cusco – 2021.

El accidente cerebrovascular es una de las principales causas de muerte y discapacidad en todo el mundo. Estudios previos han demostrado el efecto neuroprotector del extracto de pentánico de Lepidium meyenii (maca) así como de sus macamidas aisladas. El presente estudio busco conocer el efecto protector de una macamida sintética N-benciloctadecanamida (MCH1) sobre la conservación morfológica, déficits sensorio-motores y alteraciones en memoria y aprendizaje espacial. Para ello se utilizó el modelo de oclusión de la arteria cerebral media (MCAO) para inducir isquemia cerebral focal en ratas Sprague Dawley. Se administró una dosis intraperitoneal de 3 mg/kg de MCH1 antes de la oclusión; esta dosis se repitió cada 24 horas durante 10 días. Se aplicó una batería de evaluaciones neurológicas el día 3 y el día 10 después del accidente cerebrovascular (ACV) y las evaluaciones cognitivas se realizaron pre y post ACV. Los resultados muestran que el tratamiento con MCH1 reduce el área de infarto significativamente al día 10 post lesión, específicamente en las áreas de la corteza motora y sensorial. Asimismo, el tratamiento con MCH1 tiende a reducir el déficit sensorial y motor de las ratas MCAO. Los animales sometidos a MCAO no mostraron déficit en el aprendizaje y memoria espacial y el tratamiento con MCH1 no indujo ningún efecto en estos procesos cognitivos. Estos hallazgos sugieren que la aplicación de MCH1 tiene un potencial efecto neuroprotector frente a una isquemia cerebral focal, reduciendo el proceso de injuria y aliviando el área de infarto y contribuyendo a la conservación de algunas funciones sensorio-motoras.Strokes are one of the leading causes of death and disability worldwide. Previous studies have shown the neuroprotective effect of Lepidium meyenii pentane extract (maca) as well as its separate macamides. The present study aims to ascertain the protective effect of a synthetic macamide N-benzyloctadecanamide (MCH1) on morphological conservation, sensory-motor and disturbs on spatial learning and memory. To this end, the middle cerebral artery occlusion (MCAO) model was produced to induce focal cerebral ischemia in Sprague Dawley rats. An intraperitoneal dose of 3 mg/kg of MCH1 was administered prior to occlusion; this dose is repeated every 24 hours for 10 days. A battery of neurological assessments was applied on day 3 and day 10 after stroke, and cognitive assessments were performed pre- and post-stroke. The results show treatment with MCH1 reduces significantly the infarct area at day 10 post stroke, specifically in sensory and motor cortex. MCH1 treatment also reduce sensory-motor deficit in stroke rats. MCAO animals haven´t showed any change in cognitive function. These results suggest a potential neuroprotective effect of macamide MCH1 against focal ischemic damage, reducing the injury process and limiting the infarct area, as well as the preserved the sensory-motor function