bluuebunny/crossref_metadata_2025_split huggingface dataset:
Strong Convergence Theorems for a Finite Family of Nonexpansive Mappings
Authors: Shang Meijuan , Su Yongfu , Qin Xiaolong 
Published: September 2007

AbstractWe modified the classic Mann iterative process to have strong convergence theorem for a finite family of nonexpansive mappings in the framework of Hilbert spaces. Our results improve and extend the results announced by many others.
Hydrological Impacts of Deforestation on the Southeast Tibetan Plateau
Authors: Cui Xuefeng , Graf Hans-F. , Langmann Baerbel , Chen Wen , Huang Ronghui 
Published: September 2007

Abstract
The hydrological impact of forest removal on the southeast Tibetan Plateau during the second half of the last century is investigated in this study using an atmospheric general circulation model. The effects of deforestation are investigated by examining the differences between the forest replacement and control experiments. Model results demonstrate that deforestation of the southeast Tibetan Plateau would influence the local and the remote climate as well. It would lead to decreased transpiration and increased summer precipitation in the deforested area and a wetter and warmer climate on the Tibetan Plateau in summer. This may produce more runoff into the rivers originating from the Tibetan Plateau and worsen flooding disasters in the downstream areas. The numerical experiments also show that deforestation would remotely impact Asian climate, and even global climate, although the statistical significance is small. A strong drought is found at middle and lower reaches of the Yellow River, where livelihoods and economics have suffered from recent droughts. Ecosystem research on the Tibetan Plateau is a relatively new topic and needs further interdisciplinary investigation.
Probabilistic Quantitative Precipitation Forecasting Using Bayesian Model Averaging
Authors: Sloughter J. Mc Lean , Raftery Adrian E. , Gneiting Tilmann , Fraley Chris 
Published: September 2007

Abstract
Bayesian model averaging (BMA) is a statistical way of postprocessing forecast ensembles to create predictive probability density functions (PDFs) for weather quantities. It represents the predictive PDF as a weighted average of PDFs centered on the individual bias-corrected forecasts, where the weights are posterior probabilities of the models generating the forecasts and reflect the forecasts’ relative contributions to predictive skill over a training period. It was developed initially for quantities whose PDFs can be approximated by normal distributions, such as temperature and sea level pressure. BMA does not apply in its original form to precipitation, because the predictive PDF of precipitation is nonnormal in two major ways: it has a positive probability of being equal to zero, and it is skewed. In this study BMA is extended to probabilistic quantitative precipitation forecasting. The predictive PDF corresponding to one ensemble member is a mixture of a discrete component at zero and a gamma distribution. Unlike methods that predict the probability of exceeding a threshold, BMA gives a full probability distribution for future precipitation. The method was applied to daily 48-h forecasts of 24-h accumulated precipitation in the North American Pacific Northwest in 2003–04 using the University of Washington mesoscale ensemble. It yielded predictive distributions that were calibrated and sharp. It also gave probability of precipitation forecasts that were much better calibrated than those based on consensus voting of the ensemble members. It gave better estimates of the probability of high-precipitation events than logistic regression on the cube root of the ensemble mean.
A New Spatial-Scale Decomposition of the Brier Score: Application to the Verification of Lightning Probability Forecasts
Authors: Casati B. , Wilson L. J. 
Published: September 2007

Abstract
A new scale decomposition of the Brier score for the verification of probabilistic forecasts defined on a spatial domain is introduced. The technique is illustrated on the Canadian Meteorological Centre (CMC) lightning probability forecasts. Probability forecasts of lightning occurrence in 3-h time windows and 24-km spatial resolution are verified against lightning observations from the North American Lightning Detection Network (NALDN) on a domain encompassing Canada and the northern United States. Verification is performed for lightning occurrences exceeding two different thresholds, to assess the forecast performance both for modest and intense lightning activity. Observation and forecast fields are decomposed into the sum of components on different spatial scales by performing a discrete 2D Haar wavelet decomposition. Wavelets, rather than Fourier transforms, were chosen because they are locally defined, and therefore more suitable for representing discontinuous spatial fields characterized by the presence of a few sparse nonzero values, such as lightning. Verification at different spatial scales is performed by evaluating Brier score and Brier skill score for each spatial-scale component. Reliability and resolution are also evaluated on different scales. Moreover, the bias on different scales is assessed, along with the ability of the forecasts to reproduce the observed-scale structure.
The Motion of Simulated Convective Storms as a Function of Basic Environmental Parameters
Authors: Kirkpatrick J. Cody , McCaul Eugene W. , Cohen Charles 
Published: September 2007

Abstract
Based on results from a three-dimensional cloud-resolving model, it is shown that simulated convective storm motions are affected by thermodynamic as well as kinematic properties of the environment. In addition to the mean wind and its vertical shear, the effect on isolated storm motion of parameters such as bulk convective available potential energy (CAPE), the vertical distribution of buoyancy in the profile, the heights of the lifting condensation level (LCL) and level of free convection (LFC), and cloud-base temperature is considered. Storm motions show at least some sensitivity to all input parameters. Consistent with previous studies, hodograph radius has the most pronounced effect, but the vertical distribution of shear (which also influences the mean wind) affects storm evolution and propagation, even when the effective hodograph radius is unchanged. Among the thermodynamic parameters, the most significant variations occur when the LCL–LFC configuration is modified or when cloud-base temperature is changed. The effects of increases in bulk CAPE act mainly to increase the temporal variability of storm motions. This temporal variability is found to consist both of oscillations about a mean state and trends (accelerations) and is related to increases in the complexity of storm evolution with increasing CAPE. The results point to the importance of environmental factors that enhance storm intensity and rotation, which play a key role in determining storm deviate motion.
The Sensitivity of Convective Initiation to the Lapse Rate of the Active Cloud-Bearing Layer
Authors: Houston Adam L. , Niyogi Dev 
Published: September 2007

Abstract
Numerical experiments are conducted using an idealized cloud-resolving model to explore the sensitivity of deep convective initiation (DCI) to the lapse rate of the active cloud-bearing layer [ACBL; the atmospheric layer above the level of free convection (LFC)]. Clouds are initiated using a new technique that involves a preexisting airmass boundary initialized such that the (unrealistic) adjustment of the model state variables to the imposed boundary is disassociated from the simulation of convection. Reference state environments used in the experiment suite have identical mixed layer values of convective inhibition, CAPE, and LFC as well as identical profiles of relative humidity and wind. Of the six simulations conducted for the experiment set, only the three environments with the largest ACBL lapse rates support DCI. The simulated deep convection is initiated from elevated sources (parcels in the convective clouds originate near 1300 m) despite the presence of a surface-based boundary. Thermal instability release is found to be more likely in the experiments with larger ACBL lapse rates because the forced ascent at the preexisting boundary is stronger (despite nearly identical boundary depths) and because the parcels’ LFCs are lower, irrespective of parcel dilution. In one experiment without deep convection, DCI failure occurs even though thermal instability is released. Results from this experiment along with the results from a heuristic Lagrangian model reveal the existence of two convective regimes dependent on the environmental lapse rate: a supercritical state capable of supporting DCI and a subcritical state that is unlikely to support DCI. Under supercritical conditions the rate of increase in buoyancy due to parcel ascent exceeds the reduction in buoyancy due to dilution. Under subcritical conditions, the rate of increase in buoyancy due to parcel ascent is outpaced by the rate of reduction in buoyancy from dilution. Overall, results demonstrate that the lapse rate of the ACBL is useful in diagnosing and/or predicting DCI.
Analysis of the 13–14 July Gulf Surge Event during the 2004 North American Monsoon Experiment
Authors: Rogers Peter J. , Johnson Richard H. 
Published: September 2007

Abstract
Gulf surges are disturbances that move northward along the Gulf of California (GOC), frequently advecting cool, moist air from the GOC or eastern tropical Pacific Ocean into the deserts of the southwest United States and northwest Mexico during the North American Monsoon (NAM). Little attention has been given to the dynamics of these disturbances because of the lack of reliable high-resolution data across the NAM region. High temporal and spatial observations collected during the 2004 North American Monsoon Experiment are used to investigate the structure and dynamical mechanisms of a significant gulf surge on 13–14 July 2004. Integrated Sounding Systems deployed along the east coast of the GOC and an enhanced network of rawinsonde sites across the NAM region are used in this study. Observations show that the 13–14 July gulf surge occurred in two primary stages. The first stage was preceded by anomalous low-level warming along the northern GOC on 13 July. Sharp cooling, moistening, and increased low-level south-southeasterly flow followed over a 12–18-h period. Over the northern gulf, the wind reached ∼20 m s−1 at 750 m AGL. Then there was a brief respite followed by the second stage—a similar, but deeper acceleration of the southerly flow associated with the passage of Tropical Storm (TS) Blas on 14 July. The initial surge disturbance traversed the GOC at a speed of ∼17–25 m s−1 and resulted in a deepening of the mixed layer along the northern gulf. Dramatic surface pressure rises also accompanied the surge. The weight of the evidence suggests that the first stage of the overall surge itself consisted of two parts. The initial part resembled borelike disturbances initiated by convective downdrafts impinging on the low-level stable layer over the region. The secondary part was characteristic of a Kelvin wave–type disturbance, as evident in the deeper layer of sharp cooling and strong wind that ensued. Another possible explanation for the first part is that the leading edge of this Kelvin wave steepened nonlinearly into a borelike disturbance. The second stage of the surge was associated with the increased circulation around TS Blas.
On Some Aspects of the Definition of Initial Conditions for Ensemble Prediction
Authors: Descamps L. , Talagrand O. 
Published: September 2007

Abstract
Four methods for initialization of ensemble forecasts are systematically compared, namely the methods of singular vectors (SV) and bred modes (BM), as well as the ensemble Kalman filter (EnKF) and the ensemble transform Kalman filter (ETKF). The comparison is done on synthetic data with two models of the flow, namely, a low-order model introduced by Lorenz and a three-level quasigeostrophic atmospheric model. For the latter, both cases of a perfect and an imperfect model are considered. The performance of the various initialization methods is assessed in terms of the statistical reliability and resolution of the ensuing predictions. The relative performance of the four methods, which is statistically significant to a range of about 6 days, is in the order EnKF &gt; ETKF &gt; BM &gt; SV. The difference between the former two methods and the latter two is on the whole more significant than the differences between EnKF and ETKF, or between BM and SV separately. The general conclusion is that, if the quality of ensemble predictions is assessed by the degree to which the predicted ensembles statistically sample the uncertainty on the future state of the flow, the best initial ensembles are those that best statistically sample the uncertainty on the present state of the flow.
Assimilation of Global Positioning System Radio Occultation Observations into NCEP’s Global Data Assimilation System
Authors: Cucurull L. , Derber J. C. , Treadon R. , Purser R. J. 
Published: September 2007

Abstract
The Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) mission launched six small satellites in April 2006, each carrying a GPS radio occultation (RO) receiver. At final orbit, COSMIC will provide ∼2500–3000 RO soundings per day uniformly distributed around the globe in near–real time. In preparation for the assimilation of COSMIC data in an operational framework, the NCEP/Environmental Modeling Center (EMC) has successfully developed the capability of assimilating profiles of refractivity and bending angle. Each forward operator has been implemented with its own quality control and error characterization. In this paper, the infrastructure developed at NCEP/EMC to assimilate GPS RO observations, including forward models, observational and representativeness errors, and quality control procedures, is described. The advantages of using a forward operator for bending angle versus refractivity are discussed and some preliminary results on the benefits of the GPS RO in weather analysis and forecasts are presented. The different strategies adopted at NCEP/EMC to assimilate GPS RO data are aimed to select the most appropriate forward operator in the operational data assimilation system when COSMIC products are stable and routinely available to the Numerical Weather Centers. In the meantime, data from the Challenging Minisatellite Payload (CHAMP) satellite is available in non–real time and has been used in the assimilation tests to examine the potential benefits of the GPS RO–derived products. In the preliminary results presented in this study, the use of GPS RO observations slightly improves anomaly correlation scores for temperature (by ∼0.01–0.03) in the Southern Hemisphere and Tropics throughout the depth of the atmosphere while a slight degradation is found in the upper troposphere and stratosphere in the Northern Hemisphere. However, significant reduction of the temperature and humidity biases is found for all latitudes. The benefits from assimilating GPS RO data also extend to other fields, such as 500-hPa geopotential heights and tropical winds, demonstrating the potential use of GPS RO data in operational forecasting.
Real-Time, High-Resolution, Space–Time Analysis of Sea Surface Temperatures from Multiple Platforms
Authors: Lazarus Steven M. , Calvert Corey G. , Splitt Michael E. , Santos Pablo , Sharp David W. , Blottman Peter F. , Spratt Scott M. 
Published: September 2007

Abstract
A sea surface temperature (SST) analysis system designed to initialize short-term atmospheric model forecasts is evaluated for a month-long, relatively clear period in May 2004. System inputs include retrieved SSTs from the Geostationary Operational Environmental Satellite (GOES)-East and the Moderate Resolution Imaging Spectroradiometer (MODIS). The GOES SSTs are processed via a sequence of quality control and bias correction steps and are then composited. The MODIS SSTs are bias corrected and checked against the background field (GOES composites) prior to assimilation. Buoy data, withheld from the analyses, are used to bias correct the MODIS and GOES SSTs and to evaluate both the composites and analyses. The bias correction improves the identification of residual cloud-contaminated MODIS SSTs. The largest analysis system improvements are obtained from the adjustments associated with the creation of the GOES composites (i.e., a reduction in buoy/GOES composite rmse on the order of 0.3°–0.5°C). A total of 120 analyses (80 night and 40 day) are repeated for different experimental configurations designed to test the impact of the GOES composites, MODIS cloud mask, spatially varying background error covariance and decorrelation length scales, data reduction, and anisotropy. For the May 2004 period, the nighttime MODIS cloud mask is too conservative, at times removing good SST data and degrading the analyses. Nocturnal error variance estimates are approximately half that of the daytime and are relatively spatially homogeneous, indicating that the nighttime composites are, in general, superior. A 30-day climatological SST gradient is used to create anisotropic weights and a spatially varying length scale. The former improve the analyses in regions with significant SST gradients and sufficient data while the latter reduces the analysis rmse in regions where the innovations tend to be well correlated with distinct and persistent SST gradients (e.g., Loop Current). Data thinning reduces the rmse by expediting analysis convergence while simultaneously enhancing the computational efficiency of the analysis system. Based on these findings, an operational analysis configuration is proposed.
Ensemble Calibration of 500-hPa Geopotential Height and 850-hPa and 2-m Temperatures Using Reforecasts
Authors: Hamill Thomas M. , Whitaker Jeffrey S. 
Published: September 2007

Abstract
An examination of the benefits of ensemble forecast calibration was performed for three variables: 500-hPa geopotential height (Z500), 850-hPa temperature (T850), and 2-m temperature (T2M). A large reforecast dataset was used for the calibration. Two calibration methods were examined: a correction for a gross bias in the forecast and an analog method that implicitly adjusted for bias, spread, and applied a downscaling where appropriate. The characteristics of probabilistic forecasts from the raw ensemble were also considered. Forecasts were evaluated using rank histograms and the continuous ranked probability skill score. T2M rank histograms showed a high population of extreme ranks at all leads, and a correction for model bias alleviated this only slightly. The extreme ranks of Z500 rank histograms were slightly underpopulated at short leads, though slightly overpopulated at longer leads. T850 had characteristics in between those of T2M and Z500. Accordingly, Z500 was the most skillful variable without calibration and the variable least improved by calibration, and the bias correction achieved most of the improvement in skill. For T850, there was a more substantial additional increase in skill relative to the bias correction when the analog technique was applied. For T2M forecasts, probabilistic forecasts from the raw ensemble were the least skillful, the application of a bias correction substantially increased the skill, and the application of the analog technique produced the largest further increase in skill relative to the bias correction. Hence, reforecast datasets may be particularly helpful in the improvement of probabilistic forecasts of the variables that are most directly relevant to many forecast users (i.e., the sensible surface-weather variables).
Identity ambivalence and embodiment in women's accounts of the gynaecological examination
Authors: Galasiński Dariusz , Ziółkowska Justyna 
Published: September 2007

In this article we are interested in the negotiation of identities in women's narratives of their gynaecological examination and more particularly, the shifts of identity positions that permeate their stories. Taking a constructionist view of discourse and identity, we make two arguments in the article. First, we demonstrate that women talking about their gynaecological examinations constructed their selves ambiguously. The identity spaces that they discursively opened in the narratives were not inhabited. Second, we show that the embodiment of their identities — the inclusion of the body into the construction of self — fluctuates depending on the stage of the narrative of the examination.
A delicate balance: negotiating renal transplantation, immunosuppression and adherence to medical regimen
Authors: Cook Peta S. , McCarthy Alexandra 
Published: September 2007

Despite the volume of biomedical and psychosocial discourse surrounding both renal transplantation and the immune system, there is a limit to current understandings of immunosuppression in the context of kidney transplantation. For example, we do not know how the immunosuppressed renal transplant recipient experiences and understands their immune system and body. In addition, we do not know if the patient is as fixated on `graft survival' as their healthcare team or whether other concerns are more relevant. What is missing is the discourse of those who actually `live' the medically altered immune system in the context of renal transplantation. We propose that this gap in knowledge is bound to an acknowledged problem among renal transplant recipients and their healthcare teams — a lack of compliance with recommended medical regimens. Our argument here is that an exploration of patient intimacy with transplant-related immunosuppression might illuminate a different understanding of this experience that could enhance health professionals' understanding and their subsequent approach to treatment. We contend that the embodied and contextual experience of the patient needs to be equally valued in order to enhance patient outcomes.
Alpha6beta1 integrin expressed by sperm is determinant in mouse fertilization
Authors: Barraud-Lange Virginie , Naud-Barriant Nathalie , Saffar Line , Gattegno Liliane , Ducot Beatrice , Drillet Anne-Sophie , Bomsel Morgane , Wolf Jean-Philippe , Ziyyat Ahmed 
Published: September 2007

Abstract

Background
Based on inhibition tests, the alpha6beta1 integrin was suggested to be a sperm receptor, but further experiments using gene deletion techniques have shown that neither oocyte alpha6, nor beta1 integrin subunits were essential for mouse fertilization.

Results
Using Western blot analysis and immunofluorescence, we showed that the mouse sperm expresses the alpha6beta1 integrin. As for oocyte, binding of GoH3 anti-alpha6 antibody to sperm induces a specific inhibition of sperm fertilizing ability. Comparing zona-intact and zona-free eggs in fusion tests, we showed that the removal of the zona pellucida by acid treatment bypasses fertilizing oocyte alpha6beta1 integrin's function in the adhesion/fusion process.

Conclusion
These findings show that alpha6beta1 integrin is expressed by both gametes and is functional in their membranes interaction. These results and previous reports, about fertilization of alpha6 or beta1 integrin subunits deleted oocytes by wild type sperm, suggest that the presence of alpha6beta1 integrin on one of the two gamete membranes can rescue the fertilization process. This hypothesis is further supported by the exchange of membrane fragments occurring between gametes prior to fusion that we recently reported.