2,060 research outputs found

    Late Holocene vegetation and fire dynamics on the summits of the Guayana Highlands: The Uei-tepui palynological record

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    The summits of the tepuis (sandstone table mountains of the Neotropical Guayana region-Guayana Highlands, GH) have been considered valuable for palaeoecological studies due to their pristine nature, which emphasizes the role of natural (i.e. non-human) factors on ecological change. Anthropogenic fires, very frequent in the surrounding Gran Sabana (GS) uplands, have very rarely been documented in the GH, and are therefore not considered an important ecological factor in the high-tepui biome. This paper reports the palynological and charcoal results of a Late Holocene sequence from the summit of Uei-tepui (2104 m elevation), where extensive signs of fire were recently observed. Since ~. 2000 cal yr BP, the landscape of the study site has been dominated by meadows with occasional shrubs and cloud forests, which underwent expansions and contractions driven by climate changes and fire. A major vegetation shift occurred in the mid-18th century, when a sustained increase in local fires favoured the expansion of the low and spreading Cyrilla racemiflora shrublands at the expense of meadows and forests. Uei-tepui fires most probably were the result of human activities and reached the summit under study from the GS uplands through the vegetated slopes that characterize this tepui. The mostly anthropogenic nature of these fires, especially the more recent ones, is supported by the initial occurrence of wetter conditions, and by its coincidence with significant social changes in the GS indigenous populations, mainly the European contact. The emergence of fire as a disturbing agent of the GH biome highlights the need for an effective management plan in the GS uplands, where the vast majority of present-day fires originate, and designed in collaboration with the indigenous communities. Proactive conservation measures are considered even more important under future warming projections in the area. © 2016 Elsevier B.V.This research was supported by projects BIOCON 2004 90/05, BIOCON 08-188/09 (BBVA Foundation, Spain), CGL2006-00974/BOS (Ministry of Education and Science, Spain) and CGL2009-07069/BOS (Ministry of Science and Innovation, Spain) to V. Rull, and a predoctoral grant to E. Safont from the University of Barcelona. Fieldwork permits were provided by the Ministry of Science and Technology of Venezuela (no. 0000013, 5 Jan. 2007) and the Ministry of Environment of the same country (no. IE-085, 9 Feb. 2007).Peer reviewe

    Uterine NK cells are critical in shaping DC immunogenic functions compatible with pregnancy progression.

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    Dendritic cell (DC) and natural killer (NK) cell interactions are important for the regulation of innate and adaptive immunity, but their relevance during early pregnancy remains elusive. Using two different strategies to manipulate the frequency of NK cells and DC during gestation, we investigated their relative impact on the decidualization process and on angiogenic responses that characterize murine implantation. Manipulation of the frequency of NK cells, DC or both lead to a defective decidual response characterized by decreased proliferation and differentiation of stromal cells. Whereas no detrimental effects were evident upon expansion of DC, NK cell ablation in such expanded DC mice severely compromised decidual development and led to early pregnancy loss. Pregnancy failure in these mice was associated with an unbalanced production of anti-angiogenic signals and most notably, with increased expression of genes related to inflammation and immunogenic activation of DC. Thus, NK cells appear to play an important role counteracting potential anomalies raised by DC expansion and overactivity in the decidua, becoming critical for normal pregnancy progression

    Complete Genome Sequence of Escherichia coli Strain WG5

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    Escherichia colistrain WG5 is a widely used host for phage detection, in-cluding somatic coliphages employed as standard ISO method 10705-1 (2000). Here,we present the complete genome sequence of a commercialE. coliWG5 strain

    Prediction of fear acquisition in healthy control participants in a de novo fear-conditioning paradigm

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    Studies using fear-conditioning paradigms have found that anxiety patients are more conditionable than individuals without these disorders, but these effects have been demonstrated inconsistently. It is unclear whether these findings have etiological significance or whether enhanced conditionability is linked only to certain anxiety characteristics. To further examine these issues, the authors assessed the predictive significance of relevant subsyndromal characteristics in 72 healthy adults, including measures of worry, avoidance, anxious mood, depressed mood, and fears of anxiety symptoms (anxiety sensitivity), as well as the dimensions of Neuroticism and Extraversion. Of these variables, the authors found that the combination of higher levels of subsyndromal worry and lower levels of behavioral avoidance predicted heightened conditionability, raising questions about the etiological significance of these variables in the acquisition or maintenance of anxiety disorders. In contrast, the authors found that anxiety sensitivity was more linked to individual differences in orienting response than differences in conditioning per se. © 2007 Sage Publications

    Phenolic compound degradation by Pseudomonas syringae phylogroup 2 strains

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    It has recently been shown that Pseudomonas syringae strains pathogenic to woody hosts belonging to phylogroup (PG) 2 lack phenolic compound degradation pathways such as the beta-ketoadipate and protocatechuate pathways. The aim of this study was to analyse a selection of P. syringae PG 2 genomes, including those used previously to determine if they had other phenolic compound degradation pathways and to determine whether or not they were functional. Twenty-one publicly available genomes of PG 2 strains were analyzed. These strains had previously been isolated from both woody and herbaceous hosts. Phenolic degradation enzymes were present in 5 (23%) of the strains analysed, originating from both woody and herbaceous hosts. Hypothetical pathways were proposed to determine if catechol, anthranilate and benzoic acid were degraded by these strains. Both spectrophotometric and HPLC were used to determine phenolic compound degradation. The five strains with phenolic degradation enzymes were able to metabolize catechol, and HRI-W 7924 and MAFF 301072 could also metabolize anthranilate and benzoate, respectively. The study showed that even though some PG 2 strains lack the beta-ketoadipate and protocatechuate pathways, they still have phenolic compound degrading enzymes that may play a role in virulence.The Horticultural Knowledge Group (HORTGRO) and National Research Foundation (NRF).https://link.springer.com/journal/421612019-07-01am2019BiochemistryForestry and Agricultural Biotechnology Institute (FABI)Microbiology and Plant PathologyZoology and Entomolog

    Critical seasonal conditions in the reindeer-herding year: A synopsis of factors and events in Fennoscandia and north-western Russia

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    In this article, we identify what herders in Fennoscandia and northwestern Russia see as critical conditions and events in the annual reindeer herding cycle. Indigenous S´ami and Yamal reindeer herders identify eight seasons, each of which has crucial importance in its own way. Differences in perception between Fennoscandian and northwestern Russian reindeer herders about good and bad seasonal conditions are based on the degree of climatic and geographic variation, herd control and the variety of simultaneous pressures on pastures. The scope and speed of ongoing climate change in the Arctic will profoundly modify these conditions, and consequently shape critical events and outcomes in reindeer herding. The resulting challenges need to be assessed in the context of social and economic dynamics. Reindeer herders throughout Fennoscandia and Russia are concerned about future prospects of their livelihood. To adapt to climate change and develop new strategies, reindeer herders must have access to pastures; they must retain their mobility and flexibility; and their participation in land-use decisions must be endorsed. Climate change adaptation Indigenous peoples and local communities Reindeer Seasonality and harmful climatic conditionsCritical seasonal conditions in the reindeer-herding year: A synopsis of factors and events in Fennoscandia and north-western RussiapublishedVersio

    MEDICIÓN ECONÓMICA DE EVENTOS CLIMÁTICOS EXTREMOS EN EL SECTOR AGRICOLA: EL CASO DE LA SOJA EN ARGENTINA

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    Climate variability affects almost every economic activity, but especially those related to agriculture. In Argentina, primary sector and agroindustry have a high incidence in exports, regional GDP and regional employment. There has been some research in the estimation of the effects of climate change and climate variability in crops productivity of Argentina. However, those estimations are not translated into an economic loss valuation. Therefore, in this work different approaches to measure the impact of climate change and climate variability will be described, with the objective of propose a preliminary model of economic valuation. Regarding the case of study case, this model will be apply to measure the economic loss of events of extreme droughts in soybean production, which is the most import agricultural commodity exported in Argentina. This line of research constitutes the first step to provide economic valuation of loss of income necessary for the calibration of index-based insurance, climate derivatives or for the integration of fiscal funds necessary to finance adaptation or mitigations strategies to climate change.La variabilidad climática impacta en todas las actividades económicas, pero especialmente en el sector agropecuario. En el caso de Argentina, dicho sector primario, conjuntamente con el complejo agro-industrial, tienen una alta relevancia económica en términos de generación de divisas, producto bruto geográfico y generación de empleo. Actualmente se han desarrollado estudios que estiman los efectos del cambio y variabilidad climática sobre los rindes de los principales cultivos de la Región Pampeana y de otras regiones del país. No obstante, esos estudios carecen de valuaciones de índole económica. Por ello, en este trabajo se realizará una síntesis de los distintos enfoques utilizados para medir el impacto del cambio climático, y de los aquellos que abordan el fenómeno de variabilidad climática. A su vez se brindara una primera estimación económica de la pérdida de producción de soja generada por la ocurrencia de eventos climáticos extremos, particularmente eventos de sequía. Las estimaciones son de carácter agregado y son realzadas a los fines de establecer órdenes de magnitud para dimensionar la problemática. Como línea derivada, se plantea la calibración de modelos puntuales para la estimación de pérdidas económicas específicas y focalizadas que sirvan de base para la construcción de instrumentos financieros de cobertura o bien fondos fiscales de adaptación y mitigación de eventos climáticos extremos

    Evaluation of quaternized and neutral muscarinic receptor ligands in normal and DES-treated rat

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    The localization of quaternized muscarinic receptor (mAChR) antagonists, [11C]methyl tropanyl benzilate ([11C]MTRB) and [11C]methyl quinuclidinyl benzilate ([11C]MQNB), in rat pituitary was compared to that of [11C]tropanyl benzilate ([11C]TRB), a neutral antagonist. The quaternized ligands localize via a mAChR-mediated mechanism as shown by 60% reduction in radioactivity concentrations in the presence of QNB. [11C]TRB appears to localize primarily by a non-mAChR specific mechanism. Induction of pituitary prolactinomas by diethylstilbestrol resulted in a reduction of [11C]MTRB pituitary localization compared to normals. Elevated serum prolactin levels due to prolactinoma presence had no measurable effect on myocardial [11C]MTRB uptake or on K values. Bmax values for myocardial mAChR were similar for controls and for DES exposure of 10 weeks.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/29628/1/0000717.pd

    Impact of Vitamin D3 Deficiency on Phosphatidylcholine-/Ethanolamine, Plasmalogen-, Lyso-Phosphatidylcholine-/Ethanolamine, Carnitine- and Triacyl Glyceride-Homeostasis in Neuroblastoma Cells and Murine Brain

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    Vitamin D3 hypovitaminosis is associated with several neurological diseases such as Alzheimer’s disease, Parkinson’s disease or multiple sclerosis but also with other diseases such as cancer, diabetes or diseases linked to inflammatory processes. Importantly, in all of these dis eases lipids have at least a disease modifying effect. Besides its well-known property to modulate gene-expression via the VDR-receptor, less is known if vitamin D hypovitaminosis influences lipid homeostasis and if these potential changes contribute to the pathology of the diseases themselves. Therefore, we analyzed mouse brain with a mild vitamin D hypovitaminosis via a targeted shotgun lipidomic approach, including phosphatidylcholine, plasmalogens, lyso-phosphatidylcholine, (acyl- /acetyl-) carnitines and triglycerides. Alterations were compared with neuroblastoma cells cultivated in the presence and with decreased levels of vitamin D. Both in cell culture and in vivo, decreased vitamin D level resulted in changed lipid levels. While triglycerides were decreased, carnitines were increased under vitamin D hypovitaminosis suggesting an impact of vitamin D on energy metabolism. Additionally, lyso-phosphatidylcholines in particular saturated phosphatidylcholine (e.g., PC aa 48:0) and plasmalogen species (e.g., PC ae 42:0) tended to be increased. Our results suggest that vitamin D hypovitaminosis not only may affect gene expression but also may directly influence cellular lipid homeostasis and affect lipid turnover in disease states that are known for vitamin D hypovitaminosis
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