114 research outputs found

    Ecosystem Services Linked to Water and Plant Diversity in the Igualata Paramo of Hualcanga Region

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    The present investigation proposes to study the ecosystem services linked to water and floristic diversity in the Igualata paramo of the Hualcanga region; 5 sampling plots of 25 m2 were installed, with 4 subplots of 1 m2. 30 samples of terrestrial vascular plants were obtained, identifying 17 botanical families, 26 genera, and 27 species, and 1 lichen and 1 moss of unidentified family and genus. It was determined that the species that stands out with the highest importance value index was Lachemilia orgiculata with 44.06%, because the species was found in 4 of the 5 study plots. In second place we have Calamagrostis intermedia species with 8.21%, while the species Vicea sp. was the species with the lowest importance value index of 0.50%, being the species with the lowest number of individuals. The Rosaceae family presented the highest index with 39.61%. The Poaceae and Asteraceae families also present dominance in this ecosystem with values of 9.63% and 5.79%, respectively. According to the Shannon index, plots P2 and P4 were those with high diversity, which corroborates with what was obtained in the Simpson index; the Sorensen index showed us that plots P4 and P5 are very similar, plots P1 and P3 are fairly similar, and the remaining plots are dissimilar, which indicated that vegetation can be found in certain areas of the investigation. The water flow supplying the resident families of the region was found to be 8.12 L/s, and its ecological flow is of 0.83 L/s, having a flow that satisfies the needs of the inhabitants. Keywords: caudal, ecological flow, ecosystem paramo, ecosystem services, floristic diverity, indices of diversity. Resumen La presente investigación propone: estudiar los servicios ecosistémicos ligados al agua y diversidad florística en el páramo del Igualata regional Hualcanga; se instalaron cinco parcelas de muestreo de 25 m2 con 4 sub parcelas de 1 m2, se obtuvo 30 muestras de plantas vasculares terrestres, identificando 17 familias botánicas, 26 géneros y 27 especies, además se colectó 1 liquen y 1 musgo de familia, género y especie no identificado. Se determinó que la especie que sobresale con mayor índice de valor de importancia fue Lachemilia orgiculata con un 44,06%, esto se debe a que la especie se encontraba en 4 de las 5 parcelas de estudio, en segundo lugar, tenemos a Calamagrostis intermedia especie con 8,21%, mientras que la especie Vicea sp. fue la que menor índice de valor de importancia presentó con un 0,50% esto se debe a que fue la especie con menor cantidad de individuos. La familia Rosaceae presentó el mayor índice con 39,61%, las familias Poaceae, y Asteraceae presentan una dominancia en este ecosistema con valores de 9,63% 5,79%, respectivamente. De acuerdo al índice de Shannon las parcelas 2 y 4 son las que poseen diversidad alta que se corrobora con lo obtenido en el índice de Simpson; en el índice de Sorensen nos muestra que las parcelas P4 vs P5 son muy similares las parcelas P1 y P3 son medianamente similares y las parcelas restantes son disimiles lo que indica que la vegetación se puede encontrar en ciertas zonas de la investigación. El caudal que posee la Regional es de 8,12 L/s, abasteciendo a las familias y su caudal ecológico es de 0,83 L/s teniendo un caudal que satisface las necesidades de los pobladores. Palabras clave: caudal, caudal ecológico, diversidad florística, ecosistema páramo, índices de diversidad, servicios ecosistémicos.&nbsp

    Creep Measurements Confirm Steady Flow after Stress Maximum in Extension of Branched Polymer Melts

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    We provide conclusive evidence of nonmonotonic mechanical behavior in the extension of long-chain branched polymer melts. While nonmonotonic behavior is known to occur for solids, for the case of polymeric melts, this phenomenon is in direct contrast with current theoretical models. We rule out the possibility of the overshoot being an experimental artifact by confirming the existence of steady flow after a maximum in the ratio of stress to strain rate versus strain under both constant stress and constant strain-rate kinematics. This observation indicates the omission of important physics from current models for these industrially important materials, whose processing properties depend on extreme molecular extension

    Impact of Controlling the Site Distribution of Al Atoms on Catalytic Properties in Ferrierite-Type Zeolites

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    Zeolites with the ferrierite (FER) topology are synthesized using a combination of tetramethylammonium (TMA) cations with differently sized cyclic amines (pyrrolidine (Pyr), hexamethyleneimine (HMI), and 1,4- diazabicyclo[2.2.2]octane (DAB)). Using these organic structure-directing agents (SDAs), low Si/Al ratios and concentrated synthesis mixtures favor the crystallization of FER materials. Increasing the size of the cyclic amine or decreasing the aluminum content leads to the crystallization of other phases or the creation of excessive amounts of connectivity defects. TMA cations play a decisive role in the synthesis of the FER materials, and their presence allows the use of HMI to synthesize FER. Proton MAS NMR is used to quantify the accessibility of pyridine to acid sites in these FER samples, where it is found that the FER + HMI + TMA sample contains only 27% acid sites in the 8-MR channels, whereas FER + Pyr and FER + Pyr + TMA contain 89% and 84%, respectively. The constraint index (CI) test and the carbonylation of dimethyl ether (DME) with carbon monoxide are used as probe reactions to evaluate how changes in the aluminum distribution in these FER samples affect their catalytic behavior. Results show that the use of Pyr as an SDA results in the selective population of acid sites in the 8-MR channels, whereas the use of HMI generates FER zeolites with an increased concentration of acid sites in the 10-MR channels

    Characterizing degradation of palm swamp peatlands from space and on the ground: an exploratory study in the Peruvian Amazon

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    Peru has the fourth largest area of peatlands in the Tropics. Its most representative land cover on peat is a Mauritia flexuosa dominated palm swamp (thereafter called dense PS), which has been under human pressure over decades due to the high demand for the M. flexuosa fruit often collected by cutting down the entire palm. Degradation of these carbon dense forests can substantially affect emissions of greenhouse gases and contribute to climate change. The first objective of this research was to assess the impact of dense PS degradation on forest structure and biomass carbon stocks. The second one was to explore the potential of mapping the distribution of dense PS with different degradation levels using remote sensing data and methods. Biomass stocks were measured in 0.25 ha plots established in areas of dense PS with low (n = 2 plots), medium (n = 2) and high degradation (n = 4). We combined field and remote sensing data from the satellites Landsat TM and ALOS/PALSAR to discriminate between areas typifying dense PS with low, medium and high degradation and terra firme, restinga and mixed PS (not M. flexuosa dominated) forests. For this we used a Random Forest machine learning classification algorithm. Results suggest a shift in forest composition from palm to woody tree dominated forest following degradation. We also found that human intervention in dense PS translates into significant reductions in tree carbon stocks with initial (above and below-ground) biomass stocks (135.4 ± 4.8 Mg C ha−1) decreased by 11 and 17% following medium and high degradation. The remote sensing analysis indicates a high separability between dense PS with low degradation from all other categories. Dense PS with medium and high degradation were highly separable from most categories except for restinga forests and mixed PS. Results also showed that data from both active and passive remote sensing sensors are important for the mapping of dense PS degradation. Overall land cover classification accuracy was high (91%). Results from this pilot analysis are encouraging to further explore the use of remote sensing data and methods for monitoring dense PS degradation at broader scales in the Peruvian Amazon. Providing precise estimates on the spatial extent of dense PS degradation and on biomass and peat derived emissions is required for assessing national emissions from forest degradation in Peru and is essential for supporting initiatives aiming at reducing degradation activities

    Alu retrotransposons promote differentiation of human carcinoma cells through the aryl hydrocarbon receptor

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    Cell differentiation is a central process in development and in cancer growth and dissemination. OCT4 (POU5F1) and NANOG are essential for cell stemness and pluripotency; yet, the mechanisms that regulate their expression remain largely unknown. Repetitive elements account for almost half of the Human Genome; still, their role in gene regulation is poorly understood. Here, we show that the dioxin receptor (AHR) leads to differentiation of human carcinoma cells through the transcriptional upregulation of Alu retrotransposons, whose RNA transcripts can repress pluripotency genes. Despite the genome-wide presence of Alu elements, we provide evidences that those located at the NANOG and OCT4 promoters bind AHR, are transcribed by RNA polymerase-III and repress NANOG and OCT4 in differentiated cells. OCT4 and NANOG repression likely involves processing of Alu-derived transcripts through the miRNA machinery involving the Microprocessor and RISC. Consistently, stable AHR knockdown led to basal undifferentiation, impaired Alus transcription and blockade of OCT4 and NANOG repression. We suggest that transcripts produced from AHR-regulated Alu retrotransposons may control the expression of stemness genes OCT4 and NANOG during differentiation of carcinoma cells. The control of discrete Alu elements by specific transcription factors may have a dynamic role in genome regulation under physiological and diseased conditions.Trabajo financiado por: Ministerio de Economía y Competitividad. Proyectos BFU2011-22678, SAF2014-51813-R (I+D+i) para Pedro María Fernández Salguero Ministerio de Economía y Competitividad, Instituto Carlos III, Red Temática de Investigación Cooperativa en Cáncer Junta de Extremadura. Ayudas GR10008, GR15008 CICE-FEDER-P09-CTS-4980, CICE-FEDERP12-CTS-2256, Plan Nacional de I+D+I 2008–2011 y 2013–2016 (FIS-FEDER-PI11/01489, FIS-FEDERPI14/02152), PCIN-2014-115-ERA-NET NEURON II, para José Luis García Pérez European Research Council ERC-Consolidator ERC-STG-2012-233764 International Early Career Scientist Beca de la Howard Hughes Medical Institute IECS-55007420 Programa Unión Europea de Fondos FEDERpeerReviewe

    Effects on short term outcome of non-invasive ventilation use in the emergency department to treat patients with acute heart failure: A propensity score-based analysis of the EAHFE Registry

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    Objective: To assess the effects of non-invasive ventilation (NIV) in emergency department (ED) patients with acute heart failure (AHF) on short term outcomes. Methods: Patients from the EAHFE Registry (a multicenter, observational, multipurpose, cohort-designed database including consecutive AHF patients in 41 Spanish EDs) were grouped based on NIV treatment (NIV+ and NIV–groups). Using propensity score (PS) methodology, we identified two subgroups of patients matched by 38 covariates and compared regarding 30-day survival (primary outcome). Interaction was investigated for age, sex, ischemic cardiomyopathy, chronic obstructive pulmonary disease, AHF precipitated by an acute coronary syndrome (ACS), AHF classified as hypertensive or acute pulmonary edema (APE), and systolic blood pressure (SBP). Secondary outcomes were intensive care unit (ICU) admission; mechanical ventilation; in-hospital, 3-day and 7-day mortality; and prolonged hospitalization (>7 days). Results: Of 11, 152 patients from the EAHFE (age (SD): 80 (10) years; 55.5% women), 718 (6.4%) were NIV+ and had a higher 30-day mortality (HR = 2.229; 95%CI = 1.861–2.670) (p 85 years, p < 0.001), AHF associated with ACS (p = 0.045), and SBP < 100 mmHg (p < 0.001). No significant differences were found in the secondary endpoints except for more prolonged hospitalizations in NIV+ patients (OR = 1.445; 95%CI = 1.122–1.862) (p = 0.004). Conclusion: The use of NIV to treat AHF in ED is not associated with improved mortality outcomes and should be cautious in old patients and those with ACS and hypotension

    Microneedles: A New Frontier in Nanomedicine Delivery

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    This review aims to concisely chart the development of two individual research fields, namely nanomedicines, with specific emphasis on nanoparticles (NP) and microparticles (MP), and microneedle (MN) technologies, which have, in the recent past, been exploited in combinatorial approaches for the efficient delivery of a variety of medicinal agents across the skin. This is an emerging and exciting area of pharmaceutical sciences research within the remit of transdermal drug delivery and as such will undoubtedly continue to grow with the emergence of new formulation and fabrication methodologies for particles and MN. Firstly, the fundamental aspects of skin architecture and structure are outlined, with particular reference to their influence on NP and MP penetration. Following on from this, a variety of different particles are described, as are the diverse range of MN modalities currently under development. The review concludes by highlighting some of the novel delivery systems which have been described in the literature exploiting these two approaches and directs the reader towards emerging uses for nanomedicines in combination with MN

    The multichord stellar occultation by the centaur Bienor on January 11, 2019

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    Within our program of physical characterization of trans-Neptunian objects and centaurs, we predicted a stellar occultation by the centaur (54598) Bienor to occur on January 11, 2019, with good observability potential. We obtained high accuracy astrometric data to refine the prediction, resulting in a shadow path favorable for the Iberian Peninsula. This encouraged us to carry out an occultation observation campaign that resulted in five positive detections from four observing sites. This is the fourth centaur for which a multichord (more than two chords) stellar occultation has been observed so far, the other three being (2060) Chiron, (10199) Chariklo, and (95626) 2002 GZ32. From the analysis of the occultation chords, combined with the rotational light curve obtained shortly after the occultation, we determined that Bienor has an area-equivalent diameter of 150 +/- 20 km. This diameter is ~ 30 km smaller than the one obtained from thermal measurements. The position angle of the short axis of the best fitting ellipse obtained through the analysis of the stellar occultation does not match that of the spin axis derived from long-term photometric models. We also detected a strong irregularity in one of the minima of the rotational light curve that is present no matter the aspect angle at which the observations were done.We present different scenarios to reconcile the results from the different techniques.We did not detect secondary dropsrelated to potential rings or satellites. Nonetheless, similar rings in size to that of Chariklo’s cannot be discarded due to low data accuracy
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