Abstract
The potential ability of an ensemble prediction system (EPS) to represent its own varying forecast error provides strong motivation to produce an EPS over a less expensive deterministic ...forecast. Traditionally, this ability has been assessed by correlating the realized forecast error with the ensemble's dispersion. This paper revisits the limitations of the skill–spread correlation, but uses aspects of the correlation to introduce two metrics to assess an EPS's capacity to provide a reliable likelihood of its own error. Using a perfect EPS, skill–spread correlation is shown to be limited by its dependence on how “skill” and “spread” are defined and, perhaps most fatally, by its inability to distill the skill–spread reliability from the stability properties of the physical system being modeled. Building from this, it is argued there are two aspects of an ensemble's dispersion that should be assessed. First, is there enough variability in the dispersion to justify the expense of the EPS? The factor that controls the theoretical upper limit of the spread–error correlation can be useful in diagnosing this. Second, does the variable dispersion of an ensemble relate to a variable expectation of the forecast error? Representing the spread–error correlation in relation to its theoretical limit can provide a simple diagnostic of this attribute. A context for these concepts is provided by assessing two operational ensembles: western U.S. temperature forecasts and Brahmaputra River flow before and after postprocessing. It is shown that “skill–spread” reliability can be improved by postprocessing to that of a perfect EPS, but at the cost of the potential information content of the EPS's variable dispersion.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
2.
Trial & Guidelines Roumen, R.; Boelens, O.; Van Assen, T. ...
Hernia : the journal of hernias and abdominal wall surgery
19, Številka:
Suppl 1
Journal Article
We present a community data set of daily forcing and hydrologic response data for 671 small- to medium-sized basins across the contiguous United States (median basin size of 336 km2) that spans a ...very wide range of hydroclimatic conditions. Area-averaged forcing data for the period 1980-2010 was generated for three basin spatial configurations - basin mean, hydrologic response units (HRUs) and elevation bands - by mapping daily, gridded meteorological data sets to the subbasin (Daymet) and basin polygons (Daymet, Maurer and NLDAS). Daily streamflow data was compiled from the United States Geological Survey National Water Information System. The focus of this paper is to (1) present the data set for community use and (2) provide a model performance benchmark using the coupled Snow-17 snow model and the Sacramento Soil Moisture Accounting Model, calibrated using the shuffled complex evolution global optimization routine. After optimization minimizing daily root mean squared error, 90% of the basins have Nash-Sutcliffe efficiency scores greater than or equal to 0.55 for the calibration period and 34% greater than or equal to 0.8. This benchmark provides a reference level of hydrologic model performance for a commonly used model and calibration system, and highlights some regional variations in model performance. For example, basins with a more pronounced seasonal cycle generally have a negative low flow bias, while basins with a smaller seasonal cycle have a positive low flow bias. Finally, we find that data points with extreme error (defined as individual days with a high fraction of total error) are more common in arid basins with limited snow and, for a given aridity, fewer extreme error days are present as the basin snow water equivalent increases.
Stochastic on-off conductivity switching observed in phenylene-ethynylene oligomers has been explained in terms of changes in ring conformations, or electron localization, or both. We report the ...observation of stochastic on-off switching in the simplest of wired molecules: octanedithiol, decanedithiol, and dodecanedithiol bonded on an Au(111) surface. Stochastic switching was observed even when a top gold contact was pressed on by a conducting atomic force microscope tip at constant force. The rate of switching increased substantially at 60°C, a temperature at which these films are commonly annealed. Because such switching in alkanethiols is unlikely to be caused by internal molecular electronic changes and cannot be fully accounted for by breaking of the top contact, we argue that the cause is the well-known mobility of molecules tethered to gold via a thiol linkage.
The persistent achievement gap between students from poor families and their peers calls for research that examines risk factors associated with poverty and strategies for promoting resilience. ...Research demonstrates the impact of school climate on behavior and academic achievement, especially in high-poverty schools. The present study examines associations between family poverty, social supports, students' perceptions of school climate, behavior, and grades. Poverty is associated with poor grades and behavior, while positive perceptions of school climate are associated with positive grades and behavior. Perceptions of school climate moderate the association between poverty and behavior, such that students from poor families who perceive a positive school climate exhibit similar behaviors to their peers from higher income families. Implications for practice, policy, and research are discussed.
► Hierarchical regressions examine associations between family poverty, social supports, students' perceptions of school climate and two outcomes: behavior and grades. ► Family poverty is associated with poor grades and behavior. ► Positive perceptions of school climate are associated with positive grades and behavior. ► Perceptions of school climate moderate the association between poverty and behavior.
Stimulator of interferon genes (STING) is a receptor in the endoplasmic reticulum that propagates innate immune sensing of cytosolic pathogen-derived and self DNA
. The development of compounds that ...modulate STING has recently been the focus of intense research for the treatment of cancer and infectious diseases and as vaccine adjuvants
. To our knowledge, current efforts are focused on the development of modified cyclic dinucleotides that mimic the endogenous STING ligand cGAMP; these have progressed into clinical trials in patients with solid accessible tumours amenable to intratumoral delivery
. Here we report the discovery of a small molecule STING agonist that is not a cyclic dinucleotide and is systemically efficacious for treating tumours in mice. We developed a linking strategy to synergize the effect of two symmetry-related amidobenzimidazole (ABZI)-based compounds to create linked ABZIs (diABZIs) with enhanced binding to STING and cellular function. Intravenous administration of a diABZI STING agonist to immunocompetent mice with established syngeneic colon tumours elicited strong anti-tumour activity, with complete and lasting regression of tumours. Our findings represent a milestone in the rapidly growing field of immune-modifying cancer therapies.
Background. In the human immunodeficiency virus (HIV) care continuum, retention in HIV medical care and viral suppression are key goals to improve individual health outcomes and reduce HIV ...transmission. National data from clinical providers are lacking. Methods. HIV providers funded by the Ryan White HIV/AIDS Program (RWHAP) annually report demographic, service, and clinical data using encrypted unique client identifiers, and data are processed and de-duplicated to create a single record for each client. We calculated retention and viral suppression for clients who received RWHAP-funded HIV medical care in 2011. We conducted multivariate logistic regression to identify factors associated with these outcomes. Results. In 2011, an estimated 512 911 HIV-infected clients received at least 1 RWHAP-funded non–AIDS Drug Assistance Program service. Of these, 317 458(61.8%) were seen for at least 1 HIV medical care visit. Of these, 82.2% were retained in HIV medical care, and 72.6% achieved viral suppression. Viral suppression was higher among retained clients (77.7%) vs clients who were not retained (58.3%). The lowest levels of retention and viral suppression were among individuals aged 13–34 years. Conclusions. The RWHAP provides HIV medical care and support services for more than half a million poor and underinsured individuals living with HIV in the United States. Rates of retention and viral suppression are relatively high compared with other national estimates but demonstrate room for improvement, especially among youth and racial minorities. Additional improvements in retention and viral suppression will contribute to achieving the goals of the National HIV/AIDS Strategy and improve individual and public health.
Current pharmacotherapy for post-traumatic stress disorder (PTSD), a debilitating psychiatric condition that develops in a subset of traumatized individuals, is inadequate. Over the past two decades, ...numerous studies have shown that ketamine, a non-competitive NMDA receptor antagonist, exerts rapid antidepressant effects in both humans and rodents, but the anxiolytic profile of ketamine, as well as its ability to treat PTSD-related symptoms, is still unclear. Thus, we examined the ability of a single administration of ketamine to prevent the onset of PTSD-like sequelae in a chronic psychosocial stress model of PTSD. Adult male and female Sprague-Dawley rats were exposed to a cat on two occasions, in combination with chronic social instability. Immediately following the cat exposure on Day 1, rats were given intraperitoneal injections of 10 mg/kg or 15 mg/kg ketamine or vehicle; control rats were injected with vehicle. Three weeks after the second cat exposure, we assessed symptoms of hyperarousal and anxiety-like behavior in the rats. In males, chronic stress led to greater anxiety on the elevated plus maze and in the open field; in females, chronic stress resulted in an exaggerated startle response and greater anxiety in the open field. These effects were most effectively prevented by the administration of 10 mg/kg ketamine. These findings demonstrate that ketamine can prophylactically prevent the onset of PTSD-like behaviors in males and females. Their sex-dependent nature is consistent with previous preclinical research and highlights the need for future research to examine their neurobiological basis.
•Single injection of ketamine prevented PTSD-like sequelae in male and female rats.•In males, stress increased anxiety on the plus maze and in the open field.•In females, stress increased anxiety in the open field and led to hyperarousal.•10 mg/kg ketamine was most effective in preventing stressed effects in both sexes.
This paper describes a fully automated scheme that has provided calibrated 1–10-day ensemble river discharge forecasts and predictions of severe flooding of the Brahmaputra and Ganges Rivers as they ...flow into Bangladesh; it has been operational since 2003. The Bangladesh forecasting problem poses unique challenges because of the frequent life-threatening flooding of the country and because of the absence of upstream flow data from India means that the Ganges and Brahmaputra basins must be treated as if they are ungauged. The meteorological–hydrological forecast model is a hydrologic multimodel initialized by NASA and NOAA precipitation products, whose states and fluxes are forecasted forward using calibrated European Centre for Medium-Range Weather Forecasts ensemble prediction system products, and conditionally postprocessed to produce calibrated probabilistic forecasts of river discharge at the entrance points of the Ganges and Brahmaputra into Bangladesh. Forecasts with 1–10-day horizons are presented for the summers of 2003–07. Objective verification shows that the forecast system significantly outperforms both a climatological and persistence forecast at all lead times. All severe flooding events were operationally forecast with significant probability at the 10-day horizon, including the extensive flooding of the Brahmaputra in 2004 and 2007, with the latter providing advanced lead-time warnings for the evacuation of vulnerable residents.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Over the last two centuries, breeders have drastically modified the fruit quality of strawberries through artificial selection. However, there remains significant variation in quality across ...germplasm with scope for further improvements to be made. We reported extensive phenotyping of fruit quality and yield traits in a multi-parental strawberry population to allow genomic prediction and quantitative trait nucleotide (QTN) identification, thereby enabling the description of genetic architecture to inform the efficacy of implementing advanced breeding strategies. A negative relationship (
= -0.21) between total soluble sugar content and class one yield was identified, indicating a trade-off between these two essential traits. This result highlighted an established dilemma for strawberry breeders and a need to uncouple the relationship, particularly under June-bearing, protected production systems comparable to this study. A large effect of quantitative trait nucleotide was associated with perceived acidity and pH whereas multiple loci were associated with firmness. Therefore, we recommended the implementation of both marker assisted selection (MAS) and genomic prediction to capture the observed variation respectively. Furthermore, we identified a large effect locus associated with a 10% increase in the number of class one fruit and a further 10 QTN which, when combined, are associated with a 27% increase in the number of marketable strawberries. Ultimately, our results suggested that the best method to improve strawberry yield is through selecting parental lines based upon the number of marketable fruits produced per plant. Not only were strawberry number metrics less influenced by environmental fluctuations, but they had a larger additive genetic component when compared with mass traits. As such, selecting using "number" traits should lead to faster genetic gain.
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