Space-based passive microwave soil moisture retrievals and the correction for a dynamic open water fraction

The large observation footprint of low-frequency satellite microwave emissions complicates the interpretation of near-surface soil moisture retrievals. While the effect of sub-footprint lateral heterogeneity is relatively limited under unsaturated conditions, open water bodies (if not accounted for) cause a strong positive bias in the satellite-derived soil moisture retrieval. This bias is generally assumed static and associated with large, continental lakes and coastal areas. Temporal changes in the extent of smaller water bodies as small as a few percent of the sensor footprint size, however, can cause significant and dynamic biases. We analysed the influence of such small open water bodies on near-surface soil moisture products derived from actual (non-synthetic) data from the Advanced Microwave Scanning Radiometer for the Earth Observing System (AMSR-E) for three areas in Oklahoma, USA. Differences between on-ground observations, model estimates and AMSR-E retrievals were related to dynamic estimates of open water fraction, one retrieved from a global daily record based on higher frequency AMSR-E data, a second derived from the Moderate Resolution Imaging Spectroradiometer (MODIS) and a third through inversion of the radiative transfer model, used to retrieve soil moisture. The comparison demonstrates the presence of relatively small areas (<0.05) of open water in or near the sensor footprint, possibly in combination with increased, below-critical vegetation density conditions (optical density <0.8), which contribute to seasonally varying biases in excess of 0.2 (m<sup>3</sup> m<sup>−3</sup>) soil water content. These errors need to be addressed, either through elimination or accurate characterisation, if the soil moisture retrievals are to be used effectively in a data assimilation scheme

De-identifying a public use microdata file from the Canadian national discharge abstract database

<p>Abstract</p> <p>Background</p> <p>The Canadian Institute for Health Information (CIHI) collects hospital discharge abstract data (DAD) from Canadian provinces and territories. There are many demands for the disclosure of this data for research and analysis to inform policy making. To expedite the disclosure of data for some of these purposes, the construction of a DAD public use microdata file (PUMF) was considered. Such purposes include: confirming some published results, providing broader feedback to CIHI to improve data quality, training students and fellows, providing an easily accessible data set for researchers to prepare for analyses on the full DAD data set, and serve as a large health data set for computer scientists and statisticians to evaluate analysis and data mining techniques. The objective of this study was to measure the probability of re-identification for records in a PUMF, and to de-identify a national DAD PUMF consisting of 10% of records.</p> <p>Methods</p> <p>Plausible attacks on a PUMF were evaluated. Based on these attacks, the 2008-2009 national DAD was de-identified. A new algorithm was developed to minimize the amount of suppression while maximizing the precision of the data. The acceptable threshold for the probability of correct re-identification of a record was set at between 0.04 and 0.05. Information loss was measured in terms of the extent of suppression and entropy.</p> <p>Results</p> <p>Two different PUMF files were produced, one with geographic information, and one with no geographic information but more clinical information. At a threshold of 0.05, the maximum proportion of records with the diagnosis code suppressed was 20%, but these suppressions represented only 8-9% of all values in the DAD. Our suppression algorithm has less information loss than a more traditional approach to suppression. Smaller regions, patients with longer stays, and age groups that are infrequently admitted to hospitals tend to be the ones with the highest rates of suppression.</p> <p>Conclusions</p> <p>The strategies we used to maximize data utility and minimize information loss can result in a PUMF that would be useful for the specific purposes noted earlier. However, to create a more detailed file with less information loss suitable for more complex health services research, the risk would need to be mitigated by requiring the data recipient to commit to a data sharing agreement.</p

Flood forecasting using medium-range probabilistic weather prediction

Following the developments in short- and medium-range weather forecasting over the last decade, operational flood forecasting also appears to show a shift from a so-called single solution or 'best guess' deterministic approach towards a probabilistic approach based on ensemble techniques. While this probabilistic approach is now more or less common practice and well established in the meteorological community, operational flood forecasters have only started to look for ways to interpret and mitigate for end-users the prediction products obtained by combining so-called Ensemble Prediction Systems (EPS) of Numerical Weather Prediction (NWP) models with rainfall-runoff models. This paper presents initial results obtained by combining deterministic and EPS hindcasts of the global NWP model of the European Centre for Medium-Range Weather Forecasts (ECMWF) with the large-scale hydrological model LISFLOOD for two historic flood events: the river Meuse flood in January 1995 and the river Odra flood in July 1997. In addition, a possible way to interpret the obtained ensemble based stream flow prediction is proposed

Neutrophil gelatinase-associated lipocalin and microglial activity are associated with distinct postoperative behavioral changes in rats

Neutrophil gelatinase-associated lipocalin (NGAL) has recently gained interest as a marker for neuroinflammation and associated behavioral dysfunction. We aimed to explore the link between NGAL and behavior in a rat model of postoperative cognitive dysfunction (POCD). Material collected in two previous studies on POCD was analyzed and associated with outcomes for exploratory behavior and spatial learning. Plasma and hippocampal NGAL and microglial activity were analyzed. Pearson's correlations and backward linear regression were performed to study the associations between behavioral parameters, NGAL concentrations, and microglial activity. Plasma and hippocampal NGAL were increased following surgery. Plasma NGAL was associated with impaired spatial learning only, microglial activity was associated with exploratory behavior only, while hippocampal NGAL was associated with both behavioral aspects. Spatial learning was best predicted by a model containing plasma NGAL concentrations and hippocampal microglial activity. NGAL may serve as a sensitive marker in connecting the peripheral inflammatory state to POCD, while postoperative changes in exploratory behavior are better reflected by hippocampal neuroinflammation. These findings warrant further exploration in the role of NGAL in development of postoperative behavioral deficits

Differences in the association between behavior and neutrophil gelatinase-associated lipocalin in male and female rats after coronary artery ligation

Heart failure is associated with an increased risk of developing depression and cognitive dysfunction, which negatively affects prognosis. Plasma levels of neutrophil gelatinase associated lipocalin (NGAL) are increased in heart failure and depression. Moreover, NGAL levels are associated with depression in heart failure patients. Since women are at a higher risk of developing comorbid depression with heart failure, the aim of this study was to examine sex differences in the link between NGAL and behavior in a rat model of heart failure. In young adult male and female Wistar rats, myocardial infarction (MI) was induced by means of coronary artery ligation, while control rats received sham surgery. We analyzed aspects of cognition and depression/anxiety using various behavioral tests starting three weeks after surgery. Hemodynamic measurements were performed and hearts and lungs were weighed. NGAL levels in plasma, cerebrospinal fluid (CSF) and brain tissue were analyzed. MI induced impairment in cardiac contractility and relaxation, and an increase in lung weight NGAL correlated with signs of heart failure in male, but not female rats. Male MI rats displayed cognitive problems, but not depressive-like or anxiety-like behavior. No behavioral effects of MI were observed in female rats. Plasma NGAL levels were higher in male than female rats with higher concentrations in MI compared to sham. CSF NGAL was higher in MI rats compared to sham and higher in males compared to females. The number of NGAL positive cells in the paraventricular nucleus of the hypothalamus (PVN) was only increased in male MI rats. In male, but not in female rats, NGAL levels correlated with depressive-like behavior and cognitive dysfunction. Data indicate that while MI increased NGAL levels in plasma, CSF and PVN, correlations of NGAL with behavior are sex-specific, but independent of whether sham or MI surgery was performed. This suggests that inflammatory processes related to thorax surgery and their potential effects on depressive-like behavior and cognition may be sex-specific. (C) 2016 Elsevier Inc. All rights reserved

Daily GRACE gravity field solutions track major flood events in the Ganges–Brahmaputra Delta

Two daily gravity field solutions based on observations from the Gravity Recovery and Climate Experiment (GRACE) satellite mission are evaluated against daily river runoff data for major flood events in the Ganges–Brahmaputra Delta (GBD) in 2004 and 2007. The trends over periods of a few days of the daily GRACE data reflect temporal variations in daily river runoff during major flood events. This is especially true for the larger flood in 2007, which featured two distinct periods of critical flood level exceedance in the Brahmaputra River. This first hydrological evaluation of daily GRACE gravity field solutions based on a Kalman filter approach confirms their potential for gravity-based large-scale flood monitoring. This particularly applies to short-lived, high-volume floods, as they occur in the GBD with a 4–5-year return period. The release of daily GRACE gravity field solutions in near-real time may enable flood monitoring for large events

Daily GRACE gravity field solutions track major flood events in the Ganges–Brahmaputra Delta

Two daily gravity field solutions based on observations from the Gravity Recovery and Climate Experiment (GRACE) satellite mission are evaluated against daily river runoff data for major flood events in the Ganges–Brahmaputra Delta (GBD) in 2004 and 2007. The trends over periods of a few days of the daily GRACE data reflect temporal variations in daily river runoff during major flood events. This is especially true for the larger flood in 2007, which featured two distinct periods of critical flood level exceedance in the Brahmaputra River. This first hydrological evaluation of daily GRACE gravity field solutions based on a Kalman filter approach confirms their potential for gravity-based large-scale flood monitoring. This particularly applies to short-lived, high-volume floods, as they occur in the GBD with a 4–5-year return period. The release of daily GRACE gravity field solutions in near-real time may enable flood monitoring for large events