Climatic Impacts of Tropical Land Use Practices

Climatic Impacts of Tropical Land Use Practice

Overestimation of alternative splicing caused by variable probe characteristics in exon arrays

In higher eukaryotes, alternative splicing is a common mechanism for increasing transcriptome diversity. Affymetrix exon arrays were designed as a tool for monitoring the relative expression levels of hundreds of thousands of known and predicted exons with a view to detecting alternative splicing events. In this article, we have analyzed exon array data from many different human and mouse tissues and have uncovered a systematic relationship between transcript-fold change and alternative splicing as reported by the splicing index. Evidence from dilution experiments and deep sequencing suggest that this effect is of technical rather than biological origin and that it is driven by sequence features of the probes. This effect is substantial and results in a 12-fold overestimation of alternative splicing events in genes that are differentially expressed. By cross-species exon array comparison, we could further show that the systematic bias persists even across species boundaries. Failure to consider this effect in data analysis would result in the reproducible false detection of apparently conserved alternative splicing events. Finally, we have developed a software in R called COSIE (Corrected Splicing Indices for Exon arrays) that for any given set of new exon array experiments corrects for the observed bias and improves the detection of alternative splicing (available at www.fmi.ch/groups/gbioinfo

A new approach to classification of 40 years of Antarctic sea ice concentration data

In this paper, we present a characterization of Antarctic sea ice based on the classification of annual sea ice concentration (SIC) data from 1979 to 2018. A clustering algorithm was applied to provide a climatological description of significant annual cycles of SIC and their spatial distribution around the Southern Ocean. Based on these classification results, we investigate the variability of SIC cycles on decadal and inter‐annual time scales. First, we discuss significant spatial shifts of SIC cycles during 1979–1998 and 1999–2018. In the Weddell Sea and in large parts of the Ross Sea, we observed higher SIC during the summer season, and an extension of sea ice cover in winter compared to the long‐term average. Second, we introduce the Climatological Sea Ice Anomaly Index (CSIAI), which is an annual measure for year‐round sea ice anomalies of the Southern Ocean and its regional sub‐sectors. By relating selected years of significant sea ice conditions (1981, 2007 and 2014) with atmospheric influences, we demonstrate that the CSIAI is very useful for assessing inter‐annular Antarctic SIC variability. Positive and negative sea ice anomalies can be qualitatively explained by atmospheric circulation anomalies in the years 1981 and 2007. However, in 2014, the year with the largest observed sea ice extent in our time series, we found that this positive sea ice anomaly was surprisingly not associated with a stationary and inter‐seasonally persistent pattern of circulation anomaly. This suggests that sub‐seasonal to seasonal circulation anomalies and ocean‐related processes favoured the formation of the sea ice maximum in 2014. With this study we provide additional information on the long‐term annual SIC variability around Antarctica. Furthermore, our classification approach and its results have potential for application in the evaluation of sea ice model results

Resource-oriented therapeutic models in psychiatry:conceptual review

International audienc

Linking drought and wet weather in the Jordan catchment with atmospheric circulation patterns

Ponencia presentada en: VI Congreso Internacional de la Asociación Española de Climatología celebrado en Tarragona del 8 al 11 de octubre de 2008.[ES]El alcance de este estudio es la identificación de patrones de circulación sobre el Mediterráneo oriental los cuales están relacionados de una manera significativa con la precipitación extrema en la cuenca hidrográfica del Jordan. A ese fin, un método multi-objetivo de clasificación a base de lógica fuzzy se pone en practica. El método condiciona los datos de la precipitación y patrones de circulación atmosférica a gran escala diariamente. Para comenzar, se realiza la clasificación condicional de la precipitación para el período de 1961-1990 usando presión a nivel del mar y potencial geológico en 500hPa, dispuestos por el proyecto de reanálisis NCEP/NCAR. Se comprueba la plausibilidad de los patrones de circulación obtenidos para situaciones de sequia y humedas. Luego, se realiza un análisis de la frecuencia de su presencia a escala temporal de meses, años y décadas. Por último, se compara la distribución de frecuencia de los patrones de circulación para los años 1961-1990 con la distribución de frecuencia para los años 2011-2040 utilizando ECHAM5 impulsado por A1B. Se presenta y discuta el impacto del cambio climático al cambio de frecuencia en patrones de circulación en situaciones de sequia y humedas.[EN]The scope of this study is to identify circulation patterns (CPs) over the Eastern Mediterranean (EM), which are significantly linked to extreme rainfall events in the Jordan catchment. For this reason, a multi objective fuzzy logic-based classification (MOFRBC) method is applied, which conditions rainfall data to large-scale atmospheric circulation patterns on dthe aily time scale. First, the rainfall conditional classification is performed for the period 1961-1990 using Sea Level Pressure (SLP) and Geopotential Height in 500hPa (GPH500), retrieved from the NCEP/NCAR reanalysis project. The obtained drought and wet circulation patterns are checked for plausibility and a frequency analysis of their occurrence is performed on monthly, interannual and decadal time scales. Second, the CP frequency distribution of the 1961-1990 time slice is then compared to the frequency distribution of the 2011-2040 time slice using the A1B driven ECHAM5. The impact of climate change on the frequency change of droughty and wet circulation patterns is presented and discussed