55 research outputs found

    The Western Amazonian Boundary for Avifauna Determined by Species Distribution Patterns and Geographical and Ecological Features

    Get PDF
    In northern South America, an extensive tropical lowland runs 5,000 km from the Atlantic coast to the foot of the Andes. The slope is gentle until about 500 m where the eastern Andes rise abruptly. The lowland supports Amazonia, which is the most extensive tract of tropical rainforest on the planet. Most of its boundaries are well defined, but the boundary between Amazonia and the forest of the eastern slopes of the Andes has not been clearly defined. To determine for avifauna whether Amazonia is restricted to the lowland of northern South America or whether it also extends up into the eastern slopes of the Andes, different types of data were used. The results indicate that Amazonia may be restricted to the lowland that extends from the Atlantic coast to the foot of the Andes, up to about 500 m. Consequently, the number of bird species strictly endemic to Amazonia would be 290. Comparison with the distribution of vegetation on the eastern slopes of the Andes also suggests that Amazonia as a biome may be restricted to the lowland that extends from the Atlantic coast to the foot of the Andes, up to about 500 m

    Effect of abiotic stress on the production on lutein and beta-carotene by Chlamydomonas acidophila

    Get PDF
    Chlamydomonas acidophila growing autotrophically with continuous PAR light (160 µE.m-2.s-1) and 30 ºC may accumulate carotenoids which increase in response to abiotic stress, like high light intensity, UV-A radiation and temperature fluctuation. At 240 µE.m-2.s-1 the alga contains 57.5 ± 1.6 mg.l-1 of total carotenoids after 20 days of growing, which does not significantly change by an irradiance of 1000 µE.m-2.s-1. Lutein (20 ± 0.5 mg.l-1) and β-carotene (8.3 ± 0.2 mg.l-1) production were particularly high in C. acidophila, while zeaxanthine (0.2 ± 0.1 mg.l-1) was low. Enhanced production of these carotenoids was also observed in cultures illuminated with PAR light (160 µE.m-2.s-1) supplemented with moderate UV-A radiation (10 µE.m-2.s-1). Optimum algae growth takes place at 40 ºC, like the maximum amount of intracellular lutein and β-carotene. On the other hand, the presence of iron in the culture medium, in a range between 5-35 mM, significantly decreased the cell viability and the intracellular content of carotenoids, however cupper, at 1-5 mM, appears to increase the synthesis of β-carotene. The alga can growth under mixotrophic conditions, with glucose or acetate, 10 mM, as carbon source, but such conditions did not improved the intracellular content of carotenoids

    Impact of microalgae-bacteria interactions on the production of algal biomass and associated compounds

    Get PDF
    A greater insight on the control of the interactions between microalgae and other microorganisms, particularly bacteria, should be useful for enhancing the efficiency of microalgal biomass production and associated valuable compounds. Little attention has been paid to the controlled utilization of microalgae-bacteria consortia. However, the studies of microalgal-bacterial interactions have revealed a significant impact of the mutualistic or parasitic relationships on algal growth. The algal growth, for instance, has been shown to be enhanced by growth promoting factors produced by bacteria, such as indole-3-acetic acid. Vitamin B12 produced by bacteria in algal cultures and bacterial siderophores are also known to be involved in promoting faster microalgal growth. More interestingly, enhancement in the intracellular levels of carbohydrates, lipids and pigments of microalgae coupled with algal growth stimulation has also been reported. In this sense, massive algal production might occur in the presence of bacteria, and microalgae-bacteria interactions can be beneficial to the massive production of microalgae and algal products. This manuscript reviews the recent knowledge on the impact of the microalgae-bacteria interactions on the production of microalgae and accumulation of valuable compounds, with an emphasis on algal species having application in aquaculture

    Assessment of global DNA methylation in peripheral blood cell subpopulations of early rheumatoid arthritis before and after methotrexate

    Get PDF
    INTRODUCTION: DNA methylation is an epigenetic mechanism regulating gene expression that has been insufficiently studied in the blood of rheumatoid arthritis (RA) patients, as only T cells and total peripheral blood mononuclear cells (PBMCs) from patients with established RA have been studied and with conflicting results. METHOD: Five major blood cell subpopulations: T, B and NK cells, monocytes, and polymorphonuclear leukocytes, were isolated from 19 early RA patients and 17 healthy controls. Patient samples were taken before and 1 month after the start of treatment with methotrexate (MTX). Analysis included DNA methylation with high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry-selected reaction monitoring (HPLC-ESI-MS/MS-SRM) and expression levels of seven methylation-specific enzymes by quantitative polymerase chain reaction (qPCR). RESULTS: Disease-modifying anti-rheumatic drug (DMARD)-naive early RA patients showed global DNA hypomethylation in T cells and monocytes, together with a lower expression of DNA methyltrasnferase 1 (DNMT1), the maintenance DNA methyltransferase, which was also decreased in B cells. Furthermore, significantly increased expression of ten-eleven translocation1 (TET1), TET2 and TET3, enzymes involved in demethylation, was found in monocytes and of TET2 in T cells. There was also modest decreased expression of DNMT3A in B cells and of growth arrest and DNA-damage-inducible protein 45A (GADD45A) in T and B cells. Treatment with MTX reverted hypomethylation in T cells and monocytes, which were no longer different from controls, and increased global methylation in B cells. In addition, DNMT1 and DNMT3A showed a trend to reversion of their decreased expression. CONCLUSIONS: Our results confirm global DNA hypomethylation in patients with RA with specificity for some blood cell subpopulations and their reversal with methotrexate treatment. These changes are accompanied by parallel changes in the levels of enzymes involved in methylation, suggesting the possibility of regulation at this level

    Sporadic cloud-based mobile augmentation on the top of a virtualization layer: a case study of collaborative downloads in VANETs

    Get PDF
    Current approaches to Cloud-based Mobile Augmentation (CMA) leverage (cloud-based) resources to meet the requirements of rich mobile applications, so that a terminal (the so-called application node or AppN) can borrow resources lent by a set of collaborator nodes (CNs). In the most sophisticated approaches proposed for vehicular scenarios, the collaborators are nearby vehicles that must remain together near the application node because the augmentation service is interrupted when they move apart. This leads to disruption in the execution of the applications and consequently impoverishes the mobile users’ experience. This paper describes a CMA approach that is able to restore the augmentation service transparently when AppNs and CNs separate. The functioning is illustrated by a NaaS model where the AppNs access web contents that are collaboratively downloaded by a set of CNs, exploiting both roadside units and opportunistic networking. The performance of the resulting approach has been evaluated via simulations, achieving promising results in terms of number of downloads, average download times, and network overheadMinisterio de Educación y Ciencia | Ref. TIN2017-87604-

    Urgent urinary diversion by intrinsic or extrinsic obstructive disease of the urinary tract. Percutaneous nephrostomy versus ureteral stent

    Get PDF
    Introducción: La obstrucción de la vía urinaria es una patología urgente que se presenta con relativa frecuencia y que en determinados casos requiere de derivación urinaria inminente. El objetivo de este estudio es analizar los resultados y complicaciones en pacientes con obstrucción de la vía urinaria superior tras derivación urinaria con stent ureteral versus nefrostomía percutánea. Métodos: Estudio retrospectivo desde 1 Enero de 2011 a 31 Diciembre de 2012 incluyendo 134 pacientes (65 hombres, 69 mujeres) de edad media 61.2 ± 17.4 años procedentes de Urgencias y requirieron derivación urinaria urgente. Se analiza según el tipo de derivación urinaria diferentes parámetros etiológicos, estancia hospitalaria, evolución clínica y analítica y complicaciones. Resultados: De los 134 pacientes, en 89 casos se optó por colocación de stent ureteral y en 45 casos de nefrostomía percutánea. Los pacientes en los que se colocó nefrostomía percutánea eran más añosos y presentaban unos niveles más elevados de creatinina respecto al grupo de stent ureteral de forma significativa. No se encontraron diferencias estadísticamente significativas en la evolución clínica o analítica entre una u otra derivación, únicamente en la estancia hospitalaria que fue mayor para los pacientes con nefrostomía debido a la mayor edad, mayores cifras de creatinina al ingreso y mayor comorbilidad. Conclusión: No existen diferencias en los resultados y complicaciones entre stent ureteral y nefrostomía, si bien consideramos el stent ureteral como primera opción ante una obstrucción aguda de la vía, reservando la nefrostomía para casos de obstrucción maligna, sepsis con alteración de parámetros inflamatorios y mayor comorbilidad.Introduction: Obstruction of the urinary tract is a relatively frequent disease and sometimes requires urgent urinary derivation. The objective of this study was to compare outcomes and complications in patients with upper urinary tract obstruction after urinary derivation with ureteral stent or percutaneous nephrostomy. Material and Methods: A retrospective study was conducted from 1 January 2011 to 31 December 2012 in 134 patients (65 males, 69 females) with a mean age of 61.2 ± 17.4 yrs who came to our emergency department requiring urgent urinary derivation. Data were gathered on the type of urinary derivation, aetiology, length of hospital stay, clinical and analytical results and complications. Results: A ureteral stent was placed in 89 of the 134 patients and percutaneous nephrostomy in the remaining 45. Creatinine levels and age were significantly higher in the percutaneous nephrostomy versus ureteral stent group. No inter-group differences were found in clinical or analytical outcomes. The hospital stay was longer for the percutaneous nephrostomy patients, attributable to their higher mean age, admission creatinine level, and comorbidities. Conclusions: No differences in outcomes or complications were found between ureteral stent and percutaneous nephrostomy placement. Ureteral stents may be preferable in patients with acute tract obstruction and nephrostomy preferable in patients with malignant obstruction or sepsis with altered inflammatory parameters and a greater comorbidity burden

    Ancient genomes in South Patagonia reveal population movements associated with technological shifts and geography

    Get PDF
    Archaeological research documents major technological shifts among people who have lived in the southern tip of South America (South Patagonia) during the last thirteen millennia, including the development of marine-based economies and changes in tools and raw materials. It has been proposed that movements of people spreading culture and technology propelled some of these shifts, but these hypotheses have not been tested with ancient DNA. Here we report genome-wide data from 20 ancient individuals, and co-analyze it with previously reported data. We reveal that immigration does not explain the appearance of marine adaptations in South Patagonia. We describe partial genetic continuity since ~6600 BP and two later gene flows correlated with technological changes: one between 4700–2000 BP that affected primarily marine-based groups, and a later one impacting all <2000 BP groups. From ~2200–1200 BP, mixture among neighbors resulted in a cline correlated to geographic ordering along the coast.Fil: Nakatsuka, Nathan. Harvard Medical School; Estados UnidosFil: Luisi, Pierre. Universidad Nacional de Córdoba. Facultad de Filosofía y Humanidades; ArgentinaFil: Motti, Josefina María Brenda. Universidad Nacional del Centro de la Provincia de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Salemme, Monica Cira. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina. Universidad Nacional de Tierra del Fuego; ArgentinaFil: Santiago, Fernando Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: D'angelo del Campo, Manuel Domingo. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ciencias Sociales. Grupo de Estudios Interdisciplinarios sobre Poblaciones Humanas de Patagonia Austral; Argentina. Universidad Autónoma de Madrid; EspañaFil: Vecchi, Rodrigo Javier. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional del Sur; ArgentinaFil: Espinosa Parrilla, Yolanda. Consejo Superior de Investigaciones Científicas; EspañaFil: Prieto, Alfredo. Universidad de Magallanes; ChileFil: Adamski, Nicole. Harvard Medical School; Estados UnidosFil: Lawson, Ann Marie. Harvard Medical School; Estados UnidosFil: Harper, Thomas K.. University of Pennsylvania; Estados UnidosFil: Culleton, Brendan J.. University of Pennsylvania; Estados UnidosFil: Kennett, Douglas J.. University of California; Estados UnidosFil: Lalueza Fox, Carles. Consejo Superior de Investigaciones Científicas; EspañaFil: Mallick, Swapan. Harvard Medical School; Estados UnidosFil: Rohland, Nadin. Harvard Medical School; Estados UnidosFil: Guichón, Ricardo A.. Universidad Nacional del Centro de la Provincia de Buenos Aires; ArgentinaFil: Cabana, Graciela S.. University of Tennessee; Estados UnidosFil: Nores, Rodrigo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Antropología de Córdoba. Universidad Nacional de Córdoba. Facultad de Filosofía y Humanidades. Instituto de Antropología de Córdoba; ArgentinaFil: Reich, David. Harvard Medical School. Department Of Medicine; Estados Unido
    corecore