92 research outputs found
Funcionamiento familiar y resiliencia en adultos en aislamiento social por el COVID-19 de Lima Metropolitana, 2020
La presente investigación tiene como objetivo determinar la relación entre las variables
funcionamiento familiar y resiliencia en adultos en aislamiento social por el COVID-19 de
Lima Metropolitana. La metodología de la investigación es de diseño no experimental, de corte
transversal y de alcance correlacional. La escala utilizada para la medición del funcionamiento
familiar fue la Escala de Evaluación de Cohesión y Adaptabilidad Familiar (FACES III) de
Olson, Portner y Lavee (1985), y para medir la resiliencia se utilizó la Escala de Resiliencia
elaborado por Wagnild y Young (1993) conformada por cinco dimensiones. La muestra estuvo
conformada por 456 adultos de Lima Metropolitana con edades de 20 a 60 años. Se encontró
que el funcionamiento familiar tiene una relación moderada significativa y directa con la
resiliencia (p<0.0001). Por lo tanto, se concluye que en un adecuado funcionamiento familiar
habrá un óptimo nivel de resiliencia en sus integrantes, debido a que la familia influye en los
individuos que la conforman
Microbubble PhoXonic resonators: Chaos transition and transfer
We report the activation of optomechanical chaotic oscillations in microbubble resonators (MBRs) through a blue-side excitation of its optical resonances. We confirm the sequence of quasi-periodical oscillation, spectral continuum and aperiodic motion; as well as the transition to chaos without external feedback or modulation of the laser source. In particular, quasi periodic transitions and a spectral continuum are reported for MBRs with diameters up to 600 μm, whereas only an abrupt transition into a spectral con- tinuum is observed for larger microbubbles
Análise morfométrica de imagens histológicas de osso compacto humano
Neste trabalho faz-se a aplicação de técnicas de processamento de imagem e classificação à extração de características e análise morfométrica de imagens histológicas de osso compacto humano
Plan estratégico 2017-2020 para Uber
El creciente mercado de dispositivos conectados a internet ha traído nuevos de modelos de negocio. Gracias a esta mayor conectividad entre usuario-usuario y usuario-proveedor, se ha creado una nueva tendencia llamada economías colaborativas, en la que se hace menos indispensable el intermediario y con ello un ahorro de costos se refleja en el precio final al usuario. Uber nació como una idea de economía colaborativa en el 2009, y desde entonces ha tenido un crecimiento muy rápido; llegaría a los 62,1 millones de usuarios para el 2020. Uber se maneja en distintas geografías a nivel mundial, pero enfocándose en el mercado de Estados Unidos, donde se encuentra su sede central, se pueden observar distintas problemáticas que pueden afectar la sostenibilidad de su modelo de negocio, empezando por los problemas legales con asociaciones de taxistas y problemas de imagen que pueden afectar a la marca. En la presente tesis se busca plantear la estrategia que debe seguir Uber en el mercado norteamericano para los años 2017-2020. Esta estrategia debe tener como principal objetivo garantizar la sostenibilidad de Uber ante la competencia y los problemas mencionados. Los planes funcionales están alineados a lineamientos y objetivos estratégicos, basados en una estrategia competitiva de liderazgo en costos y una estrategia de crecimiento de diversificación concéntrica. El liderazgo en costos se debe realizar buscando la eficiencia operativa y aprovechando su posicionamiento de líder en el segmento de ridesharing, con su producto principal UberX. Por otro lado, para garantizar la sostenibilidad se debe seguir invirtiendo en I+D y en mantener el crecimiento de su red de usuarios
Nonlinear optical effects and optomechanical oscillations in hollow Whispering Gallery Mode microresonators: coexistence, suppression, amplification and route to chaos
Whispering Gallery Mode (WGM) hollow microcavities turn out to be the site of an extremely rich and complex phenomenological scenario when pumped with a continuous-wave laser source. The coexistence of numerous non-linear and optomechanical effects have been reviewed in this paper. In our previous works we have investigated and described non-linear emissions as the stimulated Brillouin and Raman scattering, the degenerated and non-degenerated Kerr effects, such as four wave mixing (FWM). These effects happened concomitantly to parametric optomechanical oscillations which are the consequence of the radiation pressure. We have confirmed the regenerative oscillation of acoustic eigenmodes of the cavity leading to parametric instabilities and the activation of optomechanical chaotic oscillations. Finally, we have demonstrated that the blue-side excitation of WGM resonances lead to the chaos transition with a spectral evolution depending on the cavity size
Parametrical optomechanical oscillations in phoxonic whispering gallery mode resonators
We report on the experimental and theoretical analysis of parametrical optomechanical oscillations in hollow spherical phoxonic whispering gallery mode resonators due to radiation pressure. The optically excited acoustic eigenmodes of the phoxonic cavity oscillate regeneratively leading to parametric oscillation instabilities
Population structure and spatio-temporal transmission dynamics of Plasmodium vivax after radical cure treatment in a rural village of the Peruvian Amazon.
BACKGROUND: Despite the large burden of Plasmodium vivax, little is known about its transmission dynamics. This study explored the population structure and spatio-temporal dynamics of P. vivax recurrent infections after radical cure in a two-year cohort study carried out in a rural community of the Peruvian Amazon. METHODS: A total of 37 P. vivax participants recruited in San Carlos community (Peru) between April and December 2008 were treated radically with chloroquine and primaquine and followed up monthly for two years with systematic blood sampling. All samples were screened for malaria parasites and subsequently all P. vivax infections genotyped using 15 microsatellites. Parasite population structure and dynamics were determined by computing different genetic indices and using spatio-temporal statistics. RESULTS: After radical cure, 76% of the study participants experienced one or more recurrent P. vivax infections, most of them sub-patent and asymptomatic. The parasite population displayed limited genetic diversity (He = 0.49) and clonal structure, with most infections (84%) being monoclonal. Spatio-temporal clusters of specific haplotypes were found throughout the study and persistence of highly frequent haplotypes were observed over several months within the same participants/households. CONCLUSIONS: In San Carlos community, P. vivax recurrences were commonly observed after radical treatment, and characterized by asymptomatic, sub-patent and clustered infections (within and between individuals from a few neighbouring households). Moreover low genetic diversity as well as parasite inbreeding are likely to define a clonal parasite population which has important implications on the malaria epidemiology of the study area
Population Genetics of Plasmodium vivax in the Peruvian Amazon.
BACKGROUND: Characterizing the parasite dynamics and population structure provides useful information to understand the dynamic of transmission and to better target control interventions. Despite considerable efforts for its control, vivax malaria remains a major health problem in Peru. In this study, we have explored the population genetics of Plasmodium vivax isolates from Iquitos, the main city in the Peruvian Amazon, and 25 neighbouring peri-urban as well as rural villages along the Iquitos-Nauta Road. METHODOLOGY/ RESULTS: From April to December 2008, 292 P. vivax isolates were collected and successfully genotyped using 14 neutral microsatellites. Analysis of the molecular data revealed a similar proportion of monoclonal and polyclonal infections in urban areas, while in rural areas monoclonal infections were predominant (p = 0.002). Multiplicity of infection was higher in urban (MOI = 1.5-2) compared to rural areas (MOI = 1) (p = 0.003). The level of genetic diversity was similar in all areas (He = 0.66-0.76, p = 0.32) though genetic differentiation between areas was substantial (PHIPT = 0.17, p<0.0001). Principal coordinate analysis showed a marked differentiation between parasites from urban and rural areas. Linkage disequilibrium was detected in all the areas ([Formula: see text] = 0.08-0.49, for all p<0.0001). Gene flow among the areas was stablished through Bayesian analysis of migration models. Recent bottleneck events were detected in 4 areas and a recent parasite expansion in one of the isolated areas. In total, 87 unique haplotypes grouped in 2 or 3 genetic clusters described a sub-structured parasite population. CONCLUSION/SIGNIFICANCE: Our study shows a sub-structured parasite population with clonal propagation, with most of its components recently affected by bottleneck events. Iquitos city is the main source of parasite spreading for all the peripheral study areas. The routes of transmission and gene flow and the reduction of the parasite population described are important from the public health perspective as well for the formulation of future control policies
Molecular evidence of high rates of asymptomatic P. vivax infection and very low P. falciparum malaria in Botswana
Outcomes from elective colorectal cancer surgery during the SARS-CoV-2 pandemic
This study aimed to describe the change in surgical practice and the impact of SARS-CoV-2 on mortality after surgical resection of colorectal cancer during the initial phases of the SARS-CoV-2 pandemic
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