Topological challenges in multispectral image segmentation

Land cover classification from remote sensing multispectral images has been traditionallyconducted by using mainly spectral information associated with discrete spatial units (i.e. pixels).Geometric and topological characteristics of the spatial context close to every pixel have been either not fully treated or completely ignored.This article provides a review of the strategies used by a number of researchers in order to include spatial and topological properties in image segmentation.­­­It is shown how most of researchers have proposed to perform -previous to classification- a grouping or segmentation of nearby pixels by modeling neighborhood relationships as 4-connected, 8-connected and (a, b) – connected graphs.In this object-oriented approach, however, topological concepts such as neighborhood, contiguity, connectivity and boundary suffer from ambiguity since image elements (pixels) are two-dimensional entities composing a spatially uniform grid cell (i.e. there are not uni-dimensional nor zero-dimensional elements to build boundaries). In order to solve such topological paradoxes, a few proposals have been proposed. This review discusses how the alternative of digital images representation based on Cartesian complexes suggested by Kovalevsky (2008) for image segmentation in computer vision, does not present topological flaws, typical of conventional solutions based on grid cells. However, such a proposal has not been yet applied to multispectral image segmentation in remote sensing. This review is part of the PhD in Engineering research conducted by the first author under guidance of the second one. This review concludes suggesting the need to research on the potential of using Cartesian complexes for multispectral image segmentation

Governance from below in Bolivia: a theory of local government with two empirical tests

This article examines decentralization through the lens of the local dynamics it unleashed in the much-noted case of Bolivia. It argues that the national effects of decentralization are largely the sum of its local-level effects. To understand decentralization, therefore, we must first understand how local government works. The article explores the deep economic and institutional determinants of government quality in two extremes of municipal performance. From this it derives a model of local government responsiveness as the product of political openness and substantive competition. The quality of local politics, in turn, emerges endogenously as the joint product of the lobbying and political engagement of local firms and interests and the organizational density and ability of civil society. The analysis tests the theory's predictions on a database containing all Bolivian municipalities. The theory proves robust. The combined methodology provides a higher-order empirical rigor than either approach can alone

Small Scale Propulsion: How Systematic Studies of Low Reynolds Number Physics Can Bring Micro/Nanomachines to New Horizons

Micromachines are small-scale human-made machines with remarkable potential for medical treatments, microrobotics and environmental remediation applications. However, meaningful real-world applications are missing. This is mainly caused by their small size leading to unintuitive physics of motion. Motivated by the aim of understanding the fundamental physics at the micrometer scale and thereby overcoming resulting challenges, we discuss the importance of robust models supported by experimental data. Our previously performed study on the switching in propulsion mechanisms for conical tubular catalytic micromotors will be summarized and serve as an example for discussion. We emphasize on the need for systematic experimental studies to enable the design of highly application-oriented micromachines, which can be translated into real-world scenarios

Hyaluronan synthase mediates dye translocation across liposomal membranes

<p>Abstract</p> <p>Background</p> <p>Hyaluronan (HA) is made at the plasma membrane and secreted into the extracellular medium or matrix by phospolipid-dependent hyaluronan synthase (HAS), which is active as a monomer. Since the mechanism by which HA is translocated across membranes is still unresolved, we assessed the presence of an intraprotein pore within HAS by adding purified <it>Streptococcus equisimilis </it>HAS (SeHAS) to liposomes preloaded with the fluorophore Cascade Blue (CB).</p> <p>Results</p> <p>CB translocation (efflux) was not observed with mock-purified material from empty vector control <it>E. coli </it>membranes, but was induced by SeHAS, purified from membranes, in a time- and dose-dependent manner. CB efflux was eliminated or greatly reduced when purified SeHAS was first treated under conditions that inhibit enzyme activity: heating, oxidization or cysteine modification with N-ethylmaleimide. Reduced CB efflux also occurred with SeHAS K48E or K48F mutants, in which alteration of K48 within membrane domain 2 causes decreased activity and HA product size. The above results used liposomes containing bovine cardiolipin (BCL). An earlier study testing many synthetic lipids found that the best activating lipid for SeHAS is tetraoleoyl cardiolipin (TO-CL) and that, in contrast, tetramyristoyl cardiolipin (TM-CL) is an inactivating lipid (Weigel et al, J. <it>Biol. Chem</it>. <b>281</b>, 36542, 2006). Consistent with the effects of these CL species on SeHAS activity, CB efflux was more than 2-fold greater in liposomes made with TO-CL compared to TM-CL.</p> <p>Conclusions</p> <p>The results indicate the presence of an intraprotein pore in HAS and support a model in which HA is translocated to the exterior by HAS itself.</p

Estudio de factores asociados a preeclampsia y su relación con hipertension postparto

Determinar si los factores: prematuridad del recién nacido, antecedentes de trastornos hipertensivos, obesidad y diabetes pregestacional o gestacional; asociados a preeclampsia, están relacionados con Hipertensión postparto. Materiales y Métodos. 60 pacientes preeclámpticas que dieron a luz en el Hospital Belén de Trujillo fueron incluidas en este estudio de cohortes prospectivo. Se obtuvieron sus datos como edad, severidad de la preeclampsia, exposición o no a factores como: recién nacido prematuro, antecedente de preeclampsia / historia familiar de hipertensión arterial, obesidad y diabetes pregestacional o gestacional. Luego se evaluaron los niveles de presión arterial en el puerperio. Resultados. La edad promedio de la serie total fue 27,95 ± 7,973 años (rango: 15 - 45 años). La frecuencia de preeclampsia leve fue 2 (11,8%) y 15 (88,2%) casos, y de preeclampsia severa fue 28 (65,1%) y 15 (34,9%) casos, para los grupos expuestos y no expuesto respectivamente (p < 0,05). El grupo de pacientes preeclámpticas con factores asociados presentó una mayor frecuencia de hipertensión postparto comparada con aquellas preeclámpticas sin factores asociados (70,6% vs 29,4% respectivamente; p = 0,045). Conclusiones. Las gestantes preeclámpticas que padecieron además con alguno de los cuatro factores asociados investigados, tuvieron 2,4 veces más riesgo de padecer hipertensión postparto, respecto del grupo no expuesto.To determine if the factors: prematurity of the newborn, history of hypertensive disorders, obesity and pregestational or gestational diabetes; associated with preeclampsia, are related to Postpartum hypertension. Materials and Methods. 60 preeclamptic patients who deliver at the Hospital Belén de Trujillo were included in this propective cohort study. We obtained data such as age, severity of preeclampsia, exposure to factors such as: preterm newborn, preeclampsia history / family history of hypertension, obesity and pregestational or gestational diabetes. Blood pressure levels were then evaluated in the Postpartum period. Results. The mean age of the total series was 27,95 ± 7,973 years (range: 15 - 45 years). The frequency of mild preeclampsia was 2 (11,8%) and 15 (88,2%) cases, and severe preeclampsia was 28 (65,1%) and 15 (34,9%) cases, for the groups exposed and not exposed respectively (p < 0,05). The group of preeclamptic patients with associated factors presented a highr frequency of Postpartum hypertension compared to preeclamptic without associated factors (70,6% vs 29,4% respectively; p = 0,045) Conclusion. Preeclamptic women who suffered from any of the four associated factors investigated were 2.4 times more likely to suffer from postpartum hypertension than the nonexposed group.

The Valuation of Insurance Liabilities: A Framework Based on First Principle

We describe a framework for the valuation of insurance liabilities that relies on first principles in finance theory. Key features of the economic value of liabilities are its market-consistency and the inclusion of the costs of financial frictions. We compare this framework to the Solvency II approach and highlight the differences

Plan de negocios para el ingreso a la exportación del espárrago congelado

El presente plan de negocios tiene como objetivo evaluar la posibilidad de exportar espárragos congelados para lo cual se crearía la empresa Peruvian Frozen Food (PFF). El reto principal del presente proyecto es demostrar a los directores del Grupo Matta (GM), propiedad de la familia Matta Curotto, que el incursionar en la exportación de espárragos congelados será rentable y sostenible en el tiempo por sí sola, es decir, sin necesidad de apalancarse en el know how y reconocimiento internacional de Complejo Agroindustrial Beta S.A. (empresa exportadora de alimentos que es parte del GM). Por lo tanto, deberá ser sustentado ante ellos como una “evaluación de proyecto”. El Grupo Matta (GM), de capital peruano y con 35 años de trayectoria, está compuesto por las empresas Pesquera Exalmar (ventas anuales: US$300 millones) y Complejo Agroindustrial Beta (ventas anuales: US$ 120 millones), dedicadas a la exportación de alimentos bajo la estrategia corporativa de ser tomadores de precios. En ambos casos, necesitan un eficiente manejo financiero para hacer frente a eventualidades como fenómenos climáticos y meses de poca producción. Otras empresas del GM son Taxi Remise CMV e Inmobiliaria Seville, con ventas anuales conjuntas de US$ 3 millones. La investigación se inicia con el análisis del entorno y el estudio de mercado, luego se proponen objetivos y estrategias genéricas y específicas. También se establecen los principales planes funcionales que asegurarán la ejecución del proyecto, finalizando con el análisis financiero y económico que demostrarán la rentabilidad y sostenibilidad del proyecto. Finalmente, cabe indicar que respecto a la comercialización, el alcance de la presente investigación será llegar hasta el importador-distribuidor como cliente final, pero quedarán sentadas las bases para continuar, en una segunda fase, con la investigación de mercado para llegar al consumidor como cliente último

Strategies Employed by Community-Based Service Providers to Address HIV-Associated Neurocognitive Challenges: A Qualitative Study

Background: HIV-associated neurocognitive disorders and other causes of neurocognitive challenges experienced by people living with HIV (PLWH) persist as public health concerns in developed countries. Consequently, PLWH who experience neurocognitive challenges increasingly require social support and mental health services from community-based providers in the HIV sector. Methods: Thirty-three providers from 22 AIDS service organizations across Ontario, Canada, were interviewed to determine the strategies they used to support PLWH experiencing neurocognitive difficulties. Thematic analysis was conducted to determine key themes from the interview data. Results: Three types of strategies were identified: (a) intrapersonal, (b) interpersonal, and (c) organizational. Intrapersonal strategies involved learning and staying informed about causes of neurocognitive challenges. Interpersonal strategies included providing practical assistance, information, counseling, and/or referrals to PLWH. Organizational strategies included creating dedicated support groups for PLWH experiencing neurocognitive challenges, partnering with other organizations with services not available within their own organization, and advocating for greater access to services with expertise and experience working with PLWH. Conclusion: Through concerted efforts in the future, it is likely that empirically investigating, developing, and customizing these strategies specifically to address HIV-associated neurocognitive challenges will yield improved social support and mental health outcomes for PLWH

Actitud de Marcha según Nivel Socioeconómico en Adultos Mayores Autovalentes

La marcha es fundamental para la funcionalidad de adultos mayores (AM), además su expresión actitudinal se relaciona con diferentes estados emocionales, los cuales son condicionados por el nivel socioeconómico (NSE). El propósito de esta investigación fue evaluar el comportamiento de atributos actitudinales de marcha según el NSE en AM autovalentes. Participaron este estudio 71 AM autovalentes de la comunidad de Talca-Chile, categorizados según el NSE a los cuales se les aplicó el instrumento denominado análisis de forma y esfuerzo de la marcha previo caracterización de confiabilidad. Los resultados indican que el estilo de marcha no es diferente según el NSE en AM autovalentes; sin embargo, los perfiles cualificados presentan variaciones en los anclajes las que son dependientes del género

Radiation mitigation of the intestinal acute radiation injury in mice by 1-[(4-nitrophenyl)sulfonyl]-4-phenylpiperazine.

The objective of the study was to identify the mechanism of action for a radiation mitigator of the gastrointestinal (GI) acute radiation syndrome (ARS), identified in an unbiased high-throughput screen. We used mice irradiated with a lethal dose of radiation and treated with daily injections of the radiation mitigator 1-[(4-nitrophenyl)sulfonyl]-4-phenylpiperazine to study its effects on key pathways involved in intestinal stem cell (ISC) maintenance. RNASeq, quantitative reverse transcriptase-polymerase chain reaction, and immunohistochemistry were performed to identify pathways engaged after drug treatment. Target validation was performed with competition assays, reporter cells, and in silico docking. 1-[(4-Nitrophenyl)sulfonyl]-4-phenylpiperazine activates Hedgehog signaling by binding to the transmembrane domain of Smoothened, thereby expanding the ISC pool, increasing the number of regenerating crypts and preventing the GI-ARS. We conclude that Smoothened is a target for radiation mitigation in the small intestine that could be explored for use in radiation accidents as well as to mitigate normal tissue toxicity during and after radiotherapy of the abdomen