Home About us Contact
|
Home About us Contact | ||
|
|
||
Strong Sensitivity (strong + sensitivity)
Selected AbstractsUnderstanding African easterly waves: a moist singular vector approachATMOSPHERIC SCIENCE LETTERS, Issue 3 2009Rosalind J. Cornforth Abstract Moist singular vectors (MSV) have been applied successfully to predicting mid-latitude storms growing in association with latent heat of condensation. Tropical cyclone sensitivity has also been assessed. Extending this approach to more general tropical weather systems here, MSVs are evaluated for understanding and predicting African easterly waves, given the importance of moist processes in their development. First results, without initial moisture perturbations, suggest MSVs may be used advantageously. Perturbations bear similar structural and energy profiles to previous idealised non-linear studies and observations. Strong sensitivities prevail in the metrics and trajectories chosen, and benefits of initial moisture perturbations should be appraised. Copyright © 2009 Royal Meteorological Society [source] Psychometric evaluation of the mini-social phobia inventory (Mini-SPIN) in a treatment-seeking sample,DEPRESSION AND ANXIETY, Issue 6 2007Justin W. Weeks M.A. Abstract The Mini-Social Phobia Inventory (Mini-SPIN) is a 3-item, self-rated screening instrument to assess social anxiety disorder, but its psychometric properties have not yet been examined in a sample seeking treatment for psychiatric disorders. We analyzed responses from 291 adults who telephoned the Adult Anxiety Clinic of Temple (AACT) seeking treatment for social anxiety or generalized anxiety and worry. The Mini-SPIN demonstrated strong internal consistency. Support for the convergent validity of the Mini-SPIN was provided by moderate correlations with several self-report measures and a clinician-administered measure of social anxiety completed by the subsample of callers who later came to the AACT for evaluation. Furthermore, the Mini-SPIN correlated significantly with two of three measures of functional disability, but not with a measure of life satisfaction. Correlations with measures of other constructs were nonsignificant, providing support for the discriminant validity of the Mini-SPIN. In addition, a cutoff score of 6 on the Mini-SPIN yielded strong sensitivity and diagnostic efficiency in the subsample of treatment seekers that later completed pretreatment evaluation, although the specificity of this cutoff score was not optimal in this sample. Overall, the Mini-SPIN demonstrated sound psychometric properties in this treatment-seeking sample. Depression and Anxiety 24:382,391, 2007. Published 2006 Wiley-Liss, Inc. [source] Spatial patterns of simulated transpiration response to climate variability in a snow dominated mountain ecosystemHYDROLOGICAL PROCESSES, Issue 18 2008Lindsey Christensen Abstract Transpiration is an important component of soil water storage and stream-flow and is linked with ecosystem productivity, species distribution, and ecosystem health. In mountain environments, complex topography creates heterogeneity in key controls on transpiration as well as logistical challenges for collecting representative measurements. In these settings, ecosystem models can be used to account for variation in space and time of the dominant controls on transpiration and provide estimates of transpiration patterns and their sensitivity to climate variability and change. The Regional Hydro-Ecological Simulation System (RHESSys) model was used to assess elevational differences in sensitivity of transpiration rates to the spatiotemporal variability of climate variables across the Upper Merced River watershed, Yosemite Valley, California, USA. At the basin scale, predicted annual transpiration was lowest in driest and wettest years, and greatest in moderate precipitation years (R2 = 0·32 and 0·29, based on polynomial regression of maximum snow depth and annual precipitation, respectively). At finer spatial scales, responsiveness of transpiration rates to climate differed along an elevational gradient. Low elevations (1200,1800 m) showed little interannual variation in transpiration due to topographically controlled high soil moistures along the river corridor. Annual conifer stand transpiration at intermediate elevations (1800,2150 m) responded more strongly to precipitation, resulting in a unimodal relationship between transpiration and precipitation where highest transpiration occurred during moderate precipitation levels, regardless of annual air temperatures. Higher elevations (2150,2600 m) maintained this trend, but air temperature sensitivities were greater. At these elevations, snowfall provides enough moisture for growth, and increased temperatures influenced transpiration. Transpiration at the highest elevations (2600,4000 m) showed strong sensitivity to air temperature, little sensitivity to precipitation. Model results suggest elevational differences in vegetation water use and sensitivity to climate were significant and will likely play a key role in controlling responses and vulnerability of Sierra Nevada ecosystems to climate change. Copyright © 2008 John Wiley & Sons, Ltd. [source] Horizontal resolution impact on short- and long-range forecast errorTHE QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY, Issue 649 2010Roberto Buizza Abstract The impact of horizontal resolution increases from spectral truncation T95 to T799 on the error growth of ECMWF forecasts is analysed. Attention is focused on instantaneous, synoptic-scale features represented by the 500 and 1000 hPa geopotential height and the 850 hPa temperature. Error growth is investigated by applying a three-parameter model, and improvements in forecast skill are assessed by computing the time limits when fractions of the forecast-error asymptotic value are reached. Forecasts are assessed both in a realistic framework against T799 analyses, and in a perfect-model framework against T799 forecasts. A strong sensitivity to model resolution of the skill of instantaneous forecasts has been found in the short forecast range (say up to about forecast day 3). But sensitivity has shown to become weaker in the medium range (say around forecast day 7) and undetectable in the long forecast range. Considering the predictability of ECMWF operational, high-resolution T799 forecasts of the 500 hPa geopotential height verified in the realistic framework over the Northern Hemisphere (NH), the long-range time limit ,(95%) is 15.2 days, a value that is one day shorter than the limit computed in the perfect-model framework. Considering the 850 hPa temperature verified in the realistic framework, the time limit ,(95%) is 16.6 days for forecasts verified in the realistic framework over the NH (cold season), 14.1 days over the SH (warm season) and 20.6 days over the Tropics. Although past resolution increases have been providing continuously better forecasts especially in the short forecast range, this investigation suggests that in the future, although further increases in resolution are expected to improve the forecast skill in the short and medium forecast range, simple resolution increases without model improvements would bring only very limited improvements in the long forecast range. Copyright © 2010 Royal Meteorological Society [source] A standard test for AGCMs including their physical parametrizations.ATMOSPHERIC SCIENCE LETTERS, Issue 2 2000II: results for the Met Office Model Abstract Example results are shown for the proposed aqua-planet experiments using a version of The Met Office Unified Model (UM). The zonal mean circulation exhibits strong sensitivity to the latitudinal distribution of sea-surface temperatures (SST). Longitudinal variation of SST yields information on the linearity and distribution of the convective response. Copyright © 2001 Royal Meteorological Society. [source] Synthesis, Microwave-Assisted Polymerization, and Polymer Properties of Fluorinated 2-Phenyl-2-oxazolines: A Systematic StudyCHEMISTRY - A EUROPEAN JOURNAL, Issue 33 2008Matthias Lobert Dr. Abstract We present a detailed systematic study of the synthesis and ability of fluorinated 2-phenyl-2-oxazolines to undergo polymerization. The synthesis of these compounds is based on a two-step procedure that gives the desired 2-oxazolines in moderate-to-good yields. All the compounds were fully characterized by IR and NMR (1H, 13C, and 19F) spectroscopy, mass spectrometry, and elemental analysis. The 2-oxazolines were subsequently used as monomers for living cationic ring-opening polymerization (CROP) with microwave irradiation as the heat source (T=140,°C), nitromethane as the solvent, and methyl tosylate as the initiator. The linear first-order kinetic plots of the polymerizations accompanied by a linear increase of the molecular weight with conversion and low polydispersity index (PDI) values (generally below 1.30) indicate a living polymerization mechanism. The resulting polymerization rates reflect a strong sensitivity to the quantity of fluorine substituents in general and the presence or absence of ortho -fluoro substituents of the phenyl ring in particular. All the polymers were isolated and characterized by size-exclusion chromatography and MALDI-TOF mass spectrometry. Finally, a detailed investigation of selected polymer properties was performed by using differential scanning calorimetry, thermogravimetric analysis, and contact-angle measurements, thus resulting in structure,property relationships. Whereas the thermal properties of the polymers are mostly influenced by the presence of ortho -fluoro substituents, the surface properties are mainly determined by the presence of para - and/or meta -fluoro substituents. [source] | ||||||||||