408 research outputs found
Análisis multitemporal y de la estructura horizontal de la cobertura de la tierra: parque nacional yacambú, estado lara, venezuela
Para determinar el estado de conservación de las coberturas de la tierra del Parque Nacional Yacambú para el periodo 2000-2008, se realizó un análisis de su estructura horizontal considerando su evolución temporal y composición estructural. La evolución temporal, lograda a partir de la superposición de mapas de cobertura obtenidos de imágenes de satélite, reveló que se presenta un alto grado de conservación de las coberturas en áreas distantes a las vías de acceso y una importante afectación, por expansión de la frontera agrícola, en las áreas limítrofes. La composición estructural, obtenida a través del cálculo de índices estructurales, apunta a procesos de fragmentación en algunas coberturas naturales
EFHB is a Novel Cytosolic Ca2+ Sensor That Modulates STIM1-SARAF Interaction
Background/aims: STIM1 and Orai1 are the key components of store-operated Ca2+ entry (SOCE). Among the proteins involved in the regulation of SOCE, SARAF prevents spontaneous activation of SOCE and modulates STIM1 function.
Methods: Cytosolic Ca2+ mobilization was estimated in fura-2-loaded cells using an epifluorescence inverted microscope. STIM1 interaction with Orai1, EFHB (EF-hand domain family member B, also known as CFAP21) and SARAF was detected by immunoprecipitation followed by Western blotting using specific antibodies. The involvement of EFHB in the translocation of NFAT to the nucleus was detected by confocal microscopy.
Results: Here, we report the identification of EFHB as a new SOCE regulator. EFHB interacts with STIM1 upon store depletion and dissociates through a Ca2+-dependent mechanism. RNAi-mediated silencing as well as overexpression studies revealed that EFHB plays a relevant role in the interaction of STIM1 and Orai1 upon store depletion, the activation of SOCE and NFAT translocation from the cytosol to the nucleus. Silencing EFHB expression abolished the dissociation of SARAF from STIM1, which indicates that EFHB might play an important role in the dynamic interaction between both proteins, which is relevant for the activation of Orai1 channels upon Ca2+ store depletion and their subsequent modulation via slow Ca2+-dependent inactivation.
Conclusion: Our results indicate that EFHB is a new SOCE regulator that modulates STIM1-SARAF interaction.MINECO BFU2013-45564-C2-1-P/2-P, BFU2016-74932-C2-1-P/2-P, BFU2016-74932-C2-1-PJunta de Extremadura-FEDER (Fondo Europeo de Desarrollo Regional Grants) IB16046, GR18061Junta de Extremadura-FEDER European Union (EU) IB16046Ministerio Economía y Competitividad, España IJCI-2015-25665MINECO Grant BFU2016-74932-C2-1-
Elements of intensive care bereavement follow-up services: A European survey
Background: Despite technological innovations and continuous improvement in evidence-based treatments, mortality in the intensive care unit remains high. Consequently, a large group of family members may be in need, and benefit from bereavement follow-up support. Aim: To explore elements, organization, and evaluation of ICU bereavement services in European countries. Specific objectives were to investigate: 1) the model of bereavement follow-up services (elements of support), 2) the workforce model (organization of staff), 3) the evaluation model (evaluation strategies). Study design: Cross-sectional survey of conference delegates. Methods: A paper and pen questionnaire including a cover letter assuring the respondents of anonymity and confidentiality was distributed to 250 delegates during the opening ceremony of the 2017 European federation of Critical Care Nurses associations (EfCCNa) Congress in Belfast. The questionnaire was developed from a previously validated tool describing bereavement care practices in intensive care units including questions about the content and organization of bereavement follow-up services. Frequencies were calculated in yes/no questions and content analysis was applied in additional free text comments. Results: We received 85 responses from publicly employed nurses, mainly in mixed adult ICUs. Respondents were 48 (56.5%) bedside nurses and the rest represented clinical nurse specialists, researchers, managers, or academic nurses. Bereavement follow-up had existed about 1-15 years. Important follow-up elements were: viewing the deceased in the unit 77 (90.6%), providing follow-up information 67 (79.8%), sending a letter of sympathy 17 (20%), and calling the family to arrange a meeting 27 (31%). Conclusion: Bereavement follow-up is common, but variable at European intensive care units. We recommend the development, implementation, and evaluation of evidence-based, but culture-specific, bereavement follow-up guidelines for European intensive care units. Relevance to Clinical Practice: More critical care nurses are realizing the need for bereavement follow-up guidelines. This paper provides an overview of common elements that might be considered
The application of a mechanistic model to analyze the factors that affect the lactation curve parameters of dairy sheep in Mexico
Pollott́s mechanistic model has been designed to describe lactation curve parameters based on the known biology of milk production and can be useful for analyzing the factors that affect this process. A total of 553 lactations (9956 weekly test-day records) of crossbred dairy sheep from four commercial farms located in Mexico, were analyzed to investigate environmental factors that influenced lactation curve parameters, using Pollott’s 5-parameter additive model. This model was fitted to each lactation using an iterative nonlinear procedure. The estimated parameters were maximum milk secretion potential (MSmax), relative rate of increase in cell differentiation (GR), maximum secretion loss (MSLmax), relative rate of decline in cell numbers (DR) and the proportion of parenchyma cells dead at parturition. A general linear model procedure was used to determine the effect of type of lambing, lambing number, flock and lambing season on total lactation milk yield (TMY), lactation length and estimated parameters of the Pollott model. Ewes had an average milk yield of 74.4 L with an average lactation length of 140 days. Flock had a significant (P < 0.05) effect on most of the analyzed traits, which can be explained by the different farmś management practices. The TMY were significantly (P = 0.005) higher for twin-lambing than single-lambing lactations. Sheep in their first lambing had lower TMY than those in their fourth lambing (P = 0.01), possibly explained by the lower values of MSmax (2.85 vs. 5.3 L) and the decrease in DR throughout life (P = 0.03). However, the relative GR was greatest (P = 0.04) during first lambing and then decreased as lambing number increased. Both lambing number and type of lambing also affected milk yield. The parameters of the Pollott model can be useful to explain, with a biological approximation, the dynamics of differentiation, secretion and death of mammary cells in dairy sheep
DISTRIBUCIÓN Y ABUNDANCIA DE MELANOIDES TUBERCULATA (GASTROPODA: THIARIDAE) EN LA RESERVA DE LA BIOSFERA PANTANOS DE CENTLA, TABASCO, MÉXICO.
We studied the distribution and abundance of Melanoides tuberculata in the Centla Swamps Biosphere Reserve. We sampled 19 lagoons, during the rainy (September - October 2003) dry (April - May 2004) seasons. We used the variance: Morisita’s Index (I?) and the k parameter to estimate the distribution pattern space aggregation index. We registered the species 18 lagoons. A total of 13,597 individuals were collected, the greater abundance appeared during the rainy season (8,364 individuals). All populations presented an aggregated spatial distribution pattern. Abundance was inversely correlated with chemical oxygen demand and directly correlated with nitrates during the rainy season. During the dry season, abundance was inversely correlated with salinity and directly with nitrates, nitrites and pH.Se estudió la distribución y abundancia de Melanoides tuberculata en la Reserva de la Biosfera Pantanos de Centla. Los muestreos se realizaron en 19 lagunas distribuidas en el interior de la Reserva durante la época de lluvias (septiembre y octubre 2003) y en la época de estiaje (abril y mayo 2004). Para conocer el patrón de distribución espacial se utilizaron índices de agregación: Índice de Morisita (I?) y Parámetro k. Se encontró la presencia de esta especie en 18 de las lagunas muestreadas. Se recolectaron 13,597 individuos. La mayor abundancia se presentó en la época de lluvias (8,364 individuos). Las poblaciones en cada laguna presentaron un patrón de distribución espacial agregado. Durante la época de lluvias se encontró una correlación inversa entre la abundancia y demanda química de oxígeno y directa con nitratos, y en la de estiaje inversa entre la abundancia y salinidad y directa con nitratos, nitritos y potencial de hidrógeno
Synthesis and Antiproliferative Activity of Sulfa-Michael Adducts and Thiochromenes Derived from Carbohydrates
The Michael addition reactions of carbohydrate-derived nitroalkenes with ethyl thioglycolate and 2-mercaptobenzyl alcohol were studied. Reactions were conducted under mild, solvent-free conditions with DABCO as a catalyst, affording the corresponding adducts in good yields. Furthermore, compounds resulting from the addition with 2-mercaptobenzyl alcohol were used as starting materials for the synthesis of chiral 3-nitro-2H-thiochromenes. For some of the compounds synthesized herein, the antioxidant and antiproliferative activities against a panel of human solid tumor cell lines were assayed and compared with those of carbohydrate-nitroalkene substrates.Junta de Extremadura GR15022Unión Europea FP7-REGPOT-2012-CT2012-31637-IMBRAI
Family presence during resuscitation: Validation of the risk–benefit and self-confidence scales for student nurses
© 2016, © The Author(s) 2016. Background. There is increasing debate about the advantages and disadvantages of family-witnessed resuscitation. Research about the views of healthcare providers depends upon reliable tools to measure their perceptions. Two tools have been developed for use with nurses (26-item cost-benefit tool, 17-item self-confidence tool). Objectives. Firstly, to validate these tools for use with student nurses in the UK. Secondly, to report on the perceived risks and benefits reported by student nurses, and their self-confidence in dealing with this situation. Methods. A sample of 79 student nurses were invited to complete the tools. Item-total correlations and Cronbach’s α were used to determine internal consistency. Factor analysis was computed to assess construct validity. The correlation between the two scales was explored. Results. 69 students completed a questionnaire. Very few had experience of family-witnessed resuscitation. Mean total scores were 3.16 (standard deviation 0.37; range 2.04–4.12) on the risk-benefit scale and 3.14 (standard deviation 0.66; range 1.94–4.82) on the self-confidence scale. Four of the original items were removed from the risk-benefit scale (Cronbach's α 0.86; 95% confidence interval ≥0.82). None were removed from the self-confidence scale (Cronbach's α 0.93; 95% confidence interval ≥0.91). There was a significant correlation between the two scales (r = 0.37, p = 0.002). Conclusions. There is growing evidence that these tools are valid and reliable for measuring student nurses’ perceptions about family-witnessed resuscitation
Interpretability of radiomics models is improved when using feature group selection strategies for predicting molecular and clinical targets in clear-cell renal cell carcinoma: insights from the TRACERx Renal study
BACKGROUND: The aim of this work is to evaluate the performance of radiomics predictions for a range of molecular, genomic and clinical targets in patients with clear cell renal cell carcinoma (ccRCC) and demonstrate the impact of novel feature selection strategies and sub-segmentations on model interpretability. METHODS: Contrast-enhanced CT scans from the first 101 patients recruited to the TRACERx Renal Cancer study (NCT03226886) were used to derive radiomics classification models to predict 20 molecular, histopathology and clinical target variables. Manual 3D segmentation was used in conjunction with automatic sub-segmentation to generate radiomics features from the core, rim, high and low enhancing sub-regions, and the whole tumour. Comparisons were made between two classification model pipelines: a Conventional pipeline reflecting common radiomics practice, and a Proposed pipeline including two novel feature selection steps designed to improve model interpretability. For both pipelines nested cross-validation was used to estimate prediction performance and tune model hyper-parameters, and permutation testing was used to evaluate the statistical significance of the estimated performance measures. Further model robustness assessments were conducted by evaluating model variability across the cross-validation folds. RESULTS: Classification performance was significant (p 0.1. Five of these targets (necrosis on histology, presence of renal vein invasion, overall histological stage, linear evolutionary subtype and loss of 9p21.3 somatic alteration marker) had AUROC > 0.8. Models derived using the Proposed pipeline contained fewer feature groups than the Conventional pipeline, leading to more straightforward model interpretations without loss of performance. Sub-segmentations lead to improved performance and/or improved interpretability when predicting the presence of sarcomatoid differentiation and tumour stage. CONCLUSIONS: Use of the Proposed pipeline, which includes the novel feature selection methods, leads to more interpretable models without compromising prediction performance. TRIAL REGISTRATION: NCT03226886 (TRACERx Renal
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