Methane hydrate: shifting the coexistence temperature to higher temperatures with an external electric field

In the present work, we used molecular dynamic simulations of the equilibrium NPT ensemble to examine the effect of an external electric field on the three-phase coexistence temperature of methane gas, liquid water and methane hydrate. For these simulations, we used the TIP4P/Ice rigid water model and a single-site model for methane. The simulations were implemented at two pressures, 400 and 250bar, over temperatures ranging from 285 to 320K and from 280 to 315K, respectively. The application of an external electric field in the range of 0.1-0.9caused the effect of the thermal vibrations of the water molecules to become attenuated. This resulted in a shift of the three-phase coexistence temperature to higher temperatures. Electric fields below this range did not cause a difference in the coexistence temperature, and electric fields above this range enhanced the thermal effect. The shift had a magnitude of 22.5K on average.Peer ReviewedPostprint (author's final draft

Innate Immune Activation and Subversion of Mammalian Functions by Leishmania Lipophosphoglycan

Leishmania promastigotes express several prominent glycoconjugates, either secreted or anchored to the parasite surface. Of these lipophosphoglycan (LPG) is the most abundant, and along with other phosphoglycan-bearing molecules, plays important roles in parasite infectivity and pathogenesis in both the sand fly and the mammalian host. Besides its contribution for parasite survival in the sand fly vector, LPG is important for modulation the host immune responses to favor the establishment of mammalian infection. This review will summarize the current knowledge regarding the role of LPG in Leishmania infectivity, focusing on the interaction of LPG and innate immune cells and in the subversion of mammalian functions by this molecule

Global, Regional, and National Trends of Chagas Disease from 1990 to 2019: Comprehensive Analysis of the Global Burden of Disease Study.

Background Chagas disease (CD) is a neglected tropical disease, endemic in Latin America, but due to migration and environmental changes it has become a global public health issue. Objectives To assess the global prevalence and disability-adjusted life years due to CD using findings from the Global Burden of Disease Study 2019. Methods The Global Burden of Disease data was obtained from the Global Burden of Disease Collaborative Network; results were provided by the Institute for Health Metrics and Evaluation. The prevalence and disability-adjusted life-years (DALYs) were described at a global, regional, and national level, including data from 1990 to 2019. Results Globally, CD prevalence decreased by 11.3% during the study period, from 7,292,889 cases estimated in 1990 to 6,469,283 in 2019. Moreover, the global DALY rate of CD decreased by 23.7% during the evaluated period, from 360,872 in 1990 to 275,377 in 2019. In addition, significant differences in the burden by sex, being men the most affected, age, with the elderly having the highest burden of the disease, and sociodemographic index (SDI), with countries with the lowest SDI values having the highest prevalence of the disease, were observed. Finally, the prevalence trends have followed different patterns according to the region, with a sustained decrease in Latin America, compared to an increasing trend in North America and Europe until 2010. Conclusion The global burden of CD has changed in recent decades, with a sustained decline in the number of cases. Although the majority of cases remain concentrated in Latin America, the increase observed in countries in North America and Europe highlights the importance of screening at-risk populations and raising awareness of this neglected tropical disease

Multiagent system for software monitoring and users’ activities in a network equipment

Este artículo presenta un sistema multiagente (SMA) que permite monitorear las actividades realizadas por los usuarios en los equipos de una red de área local. El concepto de distribución y el uso de la movilidad, son propiedades de los agentes que proporcionan una amplia serie de alternativas para solucionar o hacer tareas en el lugar exacto donde se requieren. Para el desarrollo de este SMA se utilizó la metodología GAIA y lenguaje AUML

Breeding season of the South American fur seal (Arctocephalus Australis, Otariidae: Carnivora): new data for establishing independent evolutionary histories?

The South American fur seal (SAFS) is distributed from Peru (Pacific Ocean) to Uruguay (Atlantic Ocean). However, there is a section of coastline of about 2,300 km along the Chilean coast where no SAFS are recorded. Based on morphological comparisons 3 geographic forms have been reported (Peruvian, South Chilean, Atlantic), whereas preliminary genetic studies suggest the presence of 3 distinct genetic types (Peruvian, South Chile, Atlantic). However, both of these approaches are support only the existence of 2 independent evolutionary histories for SAFS (Peruvian, Atlantic), in which case, we would also expect to find some differences in the species’ life histories among these locals populations (e.g., in the timing of the breeding season). In this study, we compare the breeding seasons of SAFS at Punta Pichalo (19°36’S-Chile), Isla Guafo (43°33’S-Chile), and Isla de Lobos (35°01’S-Uruguay) with data published for Punta San Juan (15°21’S-Peru). The periods for establishing territories, pupping, and mating took place on similar dates at Isla Guafo and Isla de Lobos, but occurred about a month earlier at Punta Pichalo and Punta San Juan. Pupping peaked at Isla Guafo on 15-December, at Isla de Lobos on 17-December, and at Punta Pichalo on 27-November. These differences in timing were not related to demographic, oceanographic or photoperiod conditions of the breeding sites under study, neither is related with the latitudinal effects on the breeding phenology. Based on results, we suggest that certain characteristics of life history can help identify species with independent evolutionary historie

Multiagent system for software monitoring and users’ activities in a network equipment

Este artículo presenta un sistema multiagente (SMA) que permite monitorear las actividades realizadas por los usuarios en los equipos de una red de área local. El concepto de distribución y el uso de la movilidad, son propiedades de los agentes que proporcionan una amplia serie de alternativas para solucionar o hacer tareas en el lugar exacto donde se requieren. Para el desarrollo de este SMA se utilizó la metodología GAIA y lenguaje AUML

Tumor de células de la granulosa: diagnóstico, tratamiento hormonal e intervención quirúrgica en yegua criolla colombiana.

  Severe reproductive problems in mares are related to ovarian tumors. Among these, the Granulosa Cell Tumor (GCT) is the most commonly diagnosed, although it represents only 2.5% of all the tumors in horses. The following investigation is a case study of GCT in one creole adult mare, which presented a similar behavior as the male, virilism and anestrus. An ultrasonographic examination was used to identify the tumor and GnRH was administered as hormonal treatment; in the following weeks an ovariectomy was done as a surgical treatment. The histopathologic examination of the neoplasic tissue evidenced cellular proliferation with similar morphologic characteristics as the granulosa cells, which is the definitive diagnosis for GCT. The hormonal and surgical treatment was satisfactory, verified by the cessation of abnormal behaviors and by the return of the cyclicity of the remaining ovary. It is expected that in the following months the mare can be used again to reproduction. Graves problemas reproductivos se han asociado a tumores ováricos en yeguas. Dentro de estos el Tumor de Células de la Granulosa (TCG) sigue siendo el más diagnosticado, aunque sólo representa el 2.5% de todos los tumores del equino. El siguiente es un estudio de caso de TCG en una yegua criolla adulta que manifestó comportamiento similar al macho, virilismo y anestro. Se utilizó el examen ultrasonográfico para identificar el tumor y se administró GnRH como tratamiento hormonal; en semanas posteriores se procedió a la ovariectomia como tratamiento quirúrgico. El examen histopatológico del tejido neoplásico evidenció proliferación celular con características morfológicamente semejantes a las células de la granulosa, siendo el diagnóstico definitivo TCG. Se concluye que el tratamiento hormonal y quirúrgico fue satisfactorio, lo cual se pudo comprobar por el cese de comportamientos anormales y el retorno de la ciclicidad del ovario restante, se espera que en meses posteriores la yegua pueda ser utilizada nuevamente para reproducción

Convergent evolution of floral signals underlies the success of Neotropical orchids

The great majority of plant species in the tropics require animals to achieve pollination, but the exact role of floral signals in attraction of animal pollinators is often debated. Many plants provide a floral reward to attract a guild of pollinators, and it has been proposed that floral signals of non-rewarding species may converge on those of rewarding species to exploit the relationship of the latter with their pollinators. In the orchid family (Orchidaceae), pollination is almost universally animal-mediated, but a third of species provide no floral reward, which suggests that deceptive pollination mechanisms are prevalent. Here, we examine floral colour and shape convergence in Neotropical plant communities, focusing on certain food-deceptive Oncidiinae orchids (e.g. Trichocentrum ascendens and Oncidium nebulosum) and rewarding species of Malpighiaceae. We show that the species from these two distantly related families are often more similar in floral colour and shape than expected by chance and propose that a system of multifarious floral mimicry—a form of Batesian mimicry that involves multiple models and is more complex than a simple one model–one mimic system—operates in these orchids. The same mimetic pollination system has evolved at least 14 times within the species-rich Oncidiinae throughout the Neotropics. These results help explain the extraordinary diversification of Neotropical orchids and highlight the complexity of plant–animal interactions