Evaluando los niveles tróficos de dos tiburones oceánicos del Océano Pacífico suroriental

Indexación: Web of ScienceStable isotope analyses for shortfin mako (Isurus oxyrinchus) and blue sharks (Prionace glauca) were conducted to assess their trophic position in two periods of time (before 1980 and after 2000) in the Southeastern Pacific waters (SEP). Both sharks showed that their trophic position decreased over time (P < 0.05). Many factors could be involved in this change such as dietary shifts, prey availability, or indirect fishing effects in SEP waters.RESUMEN. Para evaluar los niveles tróficos de los tiburones marrajo (Isurus oxyrinchus) y azulejo (Prionace glauca) en dos períodos de tiempo (previo a 1980 y posterior al 2000) en aguas del Pacífico suroriental (SEP), se realizaron análisis de isótopos estables. Ambos tiburones mostraron un descenso del nivel trófico en el tiempo (P < 0,05). Varios son los factores que pueden estar involucrados en este evento, como los cambios dietarios, la disponibilidad de las presas o los efectos indirectos de la pesquería en aguas del Pacífico suroriental.http://www.lajar.cl/pdf/imar/v44n2/Art%C3%ADculo_44_2_25.pd

Tunable and Growing Network Generation Model with Community Structures

Recent years have seen a growing interest in the modeling and simulation of social networks to understand several social phenomena. Two important classes of networks, small world and scale free networks have gained a lot of research interest. Another important characteristic of social networks is the presence of community structures. Many social processes such as information diffusion and disease epidemics depend on the presence of community structures making it an important property for network generation models to be incorporated. In this paper, we present a tunable and growing network generation model with small world and scale free properties as well as the presence of community structures. The major contribution of this model is that the communities thus created satisfy three important structural properties: connectivity within each community follows power-law, communities have high clustering coefficient and hierarchical community structures are present in the networks generated using the proposed model. Furthermore, the model is highly robust and capable of producing networks with a number of different topological characteristics varying clustering coefficient and inter-cluster edges. Our simulation results show that the model produces small world and scale free networks along with the presence of communities depicting real world societies and social networks.Comment: Social Computing and Its Applications, SCA 13, Karlsruhe : Germany (2013

Novel markers and targets of collective tumor cell invasion before and after anti-angiogenic therapies

[eng] Local invasion is a key cell-biological event in the metastatic cascade. In response to a changing microenvironment, cancer cells may act using two main strategies of invasion: single cell invasion and collective invasion. Determining how tumor cells initiate and sustain local invasive behavior might help to improve patient diagnosis and lead to the development of new intervention modalities. Therefore, the aim of this thesis is to elucidate which molecular mechanisms are involved in PanNETs invasion before and after anti-angiogenic therapies. Results from our group have demonstrated an irreversible increase in the incidence of invasive tumors during anti-angiogenic treatment in the RIP1-Tag2 mouse model. The RIP1-Tag2 mouse model is a valuable prototype of stepwise progression of tumorigenesis, and for this reason represents an appropriate choice for studying invasion in PanNETs. In addition, three dimensional models were developed with the aim of verifying the collective cell invasion process in βTC4 spheroids from RIP1-Tag2 tumors. First, the morphology of RIP1-Tag2 tumors was described as collective tumor cell invasion, both before and after anti-angiogenic treatment. In detail, CLDN4 expression was associated with a high invasion capacity, reflected in the barrier function stability and adhesion union between cells. Cells and spheroid βTC4 models, in turn, demonstrated the functional implication of CLDN1 in the invasion of cancer cells. Finally, in clinical samples of PanNETs patients, CLDN1 was directly associated with tumor progression. In summary, we identified a new link between barrier claudins, specifically 1 and 4, and the collective cell invasion process. In the future, through further validations, these markers could be used as tumor progression biomarkers for PanNETs tumors, as well as potential targets to intervene in collective invasion.[spa] La invasión local es un evento biológico celular clave en la cascada metastásica. En respuesta al microambiente tumoral, las células pueden actuar utilizando dos estrategias principales de invasión: la invasión de células individuales y la invasión colectiva. Determinar cómo las células tumorales inician y mantienen el comportamiento invasivo local podría contribuir en la mejora del diagnóstico del paciente y conducir al desarrollo de nuevas modalidades de intervención. Por lo tanto, el objetivo de esta tesis es determinar cuáles son los mecanismos moleculares involucrados en la invasión de PanNETs antes y después de las terapias anti angiogénicas. Resultados previos de nuestro grupo demostraron un aumento irreversible en la incidencia de tumores invasivos durante el tratamiento anti angiogénico en RIP1-Tag2. Los ratones transgénicos RIP1-Tag2 son un prototipo detallado de la progresión gradual en la tumorigénesis, por ello representan un modelo animal ideal para estudiar el proceso de invasión in vivo. Además, se desarrollaron modelos tridimensionales buscando verificar el proceso de invasión colectiva en esferoides βTC4 derivados de tumores RIP1-Tag2. En primer lugar, la morfología de los tumores RIP1-Tag2 se ha descrito como colectiva tanto antes y como después de la inhibición farmacológica de la angiogénesis. En detalle, la expresión de CLDN4 ha sido asociada a la capacidad de invasión colectiva, reflejada en la estabilidad de la función barrera y la integridad de la adhesión entre las células. Las células y esferoides βTC4, por su parte han demostrado la implicación funcional de CLDN1 en la invasión de células cancerosas. Finalmente, una asociación directa entre la expresión de CLDN1 y la progresión tumoral ha sido observada en las muestras clínicas de pacientes PanNETs. En resumen, hemos descrito una nueva conexión entre las claudinas de barrera, especialmente las CLDN1/4 y el movimiento colectivo de invasión tumoral. En el futuro, a través de validaciones adicionales, estos marcadores podrían ser aplicados como biomarcadores de progresión tumoral de PanNETs, así como potenciales dianas para la modulación de la invasión colectiva

Comparative analysis of domestic water heating thermosiphon systems tested according to the Standard ISO 9459-2

Permiso concedido para subir el documentoThe Standard ISO 9459-2 is a standard for the characterization of thermal performance of domestic water heating systems without auxiliary heating. In this study, 18 domestic water heating thermosiphon systems have been tested according to this international standard. The objective of the paper is to carry out a comparative analysis of the results obtained in these systems as a function of their volume and type of heat exchanger (tubular and double jacket). A comparative analysis of systems performance will be carried out by calculating the performance without thermal loss (a1/A) and solar fraction fSOL in different reference locations for different volume/area ratios. Also, a comparative analysis of systems performance and solar fraction will be carried out at different locations between a tubular heat exchanger tank and a double jacket heat exchanger tank. The different values obtained will be compared for the storage tank’s heat loss coefficient (Us). It will determinate the useful energy (energy with temperature above 45ºC) for the degree of mixing in the storage tank during a draw-off test

Melanismo parcial como una variación fenotípica frecuente de Philodryas chamissonis (Squamata: Dipsadidae) (Wiegmann, 1835) en la Región de O’Higgins, Chile

Unusual differences in coloration and design patterns have been described in some snake species around the world. These descriptions usually consider morphological abnormalities observed in single individuals, but not in a subgroup of the species, and few studies have evaluated the distribution of snake species subgroups with similar coloration and design patterns. In this study, we describe in central Chile the distribution of a subgroup, non-geographically isolated, of the endemic snake Philodryas chamissonis, presenting a similar design pattern named partial melanism, phenotypic variation showing a greater expression in the O’Higgins region, without records at the north of Maipo River.Se han descrito diferencias inusuales en patrones de diseño y coloración en varias especies de serpientes en todo el mundo. Estas descripciones usualmente consideran las diferencias morfológicas observadas en individuos, pero no en un subgrupo de la especie. Pocos estudios han evaluado la distribución de subgrupos de especies de serpientes con patrones de diseño y coloración similares. En este estudio, describimos en Chile central, la distribución de un subgrupo, no aislado geográficamente, de la serpiente endémica Philodryas chamissonis, que presenta un patrón de diseño similar denominado melanismo parcial, una variación fenotípica que mayormente se expresa en la Región de O’Higgins, sin registros hacia el norte del Rio Maipo

CONTEMPORARY ECONOMIC DETERMINANTS FOR THE CHOICE OF THE LEADERS OF THE BRAZILIAN PUBLIC ADMINISTRATION

The Brazilian national elections of 2018 constitute a milestone as the first election in the history of the Brazilian public administration in which there was restriction of donations of legal entities. This paper aims to analyze the influence of economic power on electoral choice, for which a prediction model based on financial and political-ideological variables is proposed, identifying if the odds ratio is increased for candidates with greater economic-financial disposition. We proposed a logistic regression model and estimated the probability of success in the electoral campaign and its relationship with the variables. We collected the data from the open base of the Brazilian Electoral Justice, totaling a universe of 46,867 valid applications in 2018 and 2014. The results show a new logistic regression model, in which it was verified that the candidate's condition to seek his re-election is the factor of greater relationship with the ratio of chances of electoral success, increasing by 6 times the chances of a candidate succeeding in the election. Economic-financial variables of interest confirmed the influence that economic power has on the election process in the same way as the dominant ideology in central government, leaving the results of financing by legal entities conflicting

O papel dos valores individuais no comportamento do uso de cupons de desconto

Purpose – The research analyzed the determinants (Performance Expectation, Expectation of Effort, Social Influence, Facilitating Conditions, Hedonic Motivation, Value and Habit) of the intention and the behavior of using online discount coupons, through UTAUT2 in the Brazilian context. Design/methodology/approach – The survey was adopted with an instrument adapted from Yang (2010) and Christino et al. (2019) validated by experts. Made available online, the instrument collected 309 responses for analysis using the structural equation modeling technique. Findings – The results validated the positive relationships for Facilitating Conditions, Hedonic Motivation, Perceived Value, Habit and Performance Expectation - the highest’s coefficients. The influence of Expectation on Effort and Social Influence has not been validated. Research limitations/implications – The results cannot be generalized to all Brazilian individuals, in addition to considering recognized determinants of international literature. For this reason, suggestions are made for continuing and deepening the research. Practical implications – The results contribute by indicating the main perceptions that lead to the intention and use of discount coupons, which are the performance expectation and the habit. Thus, managers can develop their sales strategies considering such factors while society can establish strategies to more sustainable purchases. Originality/value – The research discusses the determinants of UTAUT2 in the Brazilian context to explain the intention and behavior of using online discount coupons, which are grouped together are unprecedented in Brazilian literature.Objetivo – A pesquisa analisou os determinantes (Expectativa de Desempenho, Expectativa de Esforço, Influência Social, Condições Facilitadoras, Motivação Hedônica, Valor e Hábito) da intenção e comportamento de uso de cupons de desconto on-line, por meio da UTAUT2 no contexto brasileiro. Metodologia – Adotou-se a survey com instrumento adaptado de Yang (2010) e Christino et al. (2019) validado por especialistas. Disponibilizado por meio on-line, o instrumento coletou para análise 309 respostas, analisadas a partir da técnica de modelagem de equações estruturais. Resultados – Os resultados validaram as relações positivas para Condições Facilitadoras, Desempenho Hedônico, Valor Percebido, Hábito e Expectativa de Desempenho – a de maior coeficiente. A influência da Expectativa de Esforço e daInfluência Social não foram validadas. Limitações Teóricas/Implicações – Os resultados não podem ser generalizados a todos os indivíduos brasileiros, além de considerar determinantes reconhecidos da literatura internacional. Por isso, são apresentadas sugestões para continuidade e aprofundamento da pesquisa. Implicações Práticas – Os resultados contribuem a medida que indicam as principais percepções que levam à intenção e ao uso de cupons de desconto, quais sejam o desempenho utilitário e o hábito. Assim, gestores podem desenvolver suas estratégias de vendas considerando tais fatores enquanto a sociedade pode estabelecer estratégias para compras mais sustentáveis. Originalidade – A pesquisa discute os determinantes da UTAUT2 no contexto brasileiro para explicar a intenção e o comportamento de uso de cupons de desconto, o que agrupados são inéditos na literatura brasileira