bluuebunny/crossref_metadata_2025_split huggingface dataset:
Errors in Estimating Raindrop Size Distribution Parameters Employing Disdrometer and Simulated Raindrop Spectra
Authors: Cao Qing , Zhang Guifu 
Published: August 2008

Abstract
There have been debates and differences of opinion over the validity of using drop size distribution (DSD) models to characterize precipitation microphysics and to retrieve DSD parameters from multiparameter radar measurements. In this paper, simulated and observed rain DSDs are used to evaluate moment estimators. Seven estimators for gamma DSD parameters are evaluated in terms of the biases and fractional errors of five integral parameters: radar reflectivity (ZH), differential reflectivity (ZDR), rainfall rate (R), mean volume diameter (Dm), and total number concentration (NT). It is shown that middle-moment estimators such as M234 (using the second-third-fourth moments) produce smaller errors than lower- and higher-moment estimators if the DSD follows the gamma distribution. However, if there are model errors, the performance of M234 degrades. Even though the DSD parameters can be biased in moment estimators, integral parameters are usually not. Maximum likelihood (ML) and L-moment (LM) estimators perform similarly to low-moment estimators such as M012. They are sensitive to both model error and the measurement errors of the low ends of DSDs. The overall differences among M234, M246, and M346 are not substantial for the five evaluated parameters. This study also shows that the discrepancy between the radar and disdrometer observations cannot be reduced by using these estimators. In addition, the previously found constrained-gamma model is shown not to be exclusively determined by error effects. Rather, it is equivalent to the mean function of normalized DSDs derived through Testud’s approach, and linked to precipitation microphysics.
Blocking in Areas of Complex Topography, and Its Influence on Rainfall Distribution
Authors: Hughes Mimi , Hall Alex , Fovell Robert G. 
Published: August 2008

Abstract
Using a 6-km-resolution regional climate simulation of Southern California, the effect of orographic blocking on the precipitation climatology is examined. To diagnose whether blocking occurs, precipitating hours are categorized by a bulk Froude number. The precipitation distribution becomes much more spatially homogeneous as the Froude number decreases, and an inspection of winds confirms that this results from the increasing prevalence of orographic blocking. Low Froude (Froude approximately less than 1), blocked cases account for a large fraction of climatological precipitation, particularly at the coastline where more than half is attributable to blocked cases. Thus, the climatological precipitation–slope relationship seen in observations and in the simulation is a hybrid of blocked and unblocked cases.
Simulated precipitation distributions are compared to those predicted by a simple linear model that includes only rainfall arising from direct forced topographic ascent. The agreement is nearly perfect for high Froude (Froude substantially larger than 1) cases but degrades dramatically as the index decreases; as blocking becomes more prevalent, the precipitation–slope relationship becomes continuously weaker than that predicted by the linear model. Because of its high fidelity during unblocked cases, it is surmised that blocking effects are the primary limitation preventing the linear model from accurately representing precipitation climatology and that the representation would be significantly improved during low Froude hours by the addition of a term to reduce the effective slope of the topography. These results suggest orographic blocking may substantially affect climatological precipitation distributions in similarly configured coastal areas.
Large Eddy Simulation of the Diurnal Cycle in Southeast Pacific Stratocumulus
Authors: Caldwell Peter , Bretherton Christopher S. 
Published: August 2008

Abstract
This paper describes a series of 6-day large eddy simulations of a deep, sometimes drizzling stratocumulus-topped boundary layer based on forcings from the East Pacific Investigation of Climate (EPIC) 2001 field campaign. The base simulation was found to reproduce the observed mean boundary layer properties quite well. The diurnal cycle of liquid water path was also well captured, although good agreement appears to result partially from compensating errors in the diurnal cycles of cloud base and cloud top due to overentrainment around midday. At all times of the day, entrainment is found to be proportional to the vertically integrated buoyancy flux. Model stratification matches observations well; turbulence profiles suggest that the boundary layer is always at least somewhat decoupled. Model drizzle appears to be too sensitive to liquid water path and subcloud evaporation appears to be too weak. Removing the diurnal cycle of subsidence had little effect on simulated liquid water path. Simulations with changed droplet concentration and drizzle susceptibility showed large liquid water path differences at night, but differences were quite small at midday. Droplet concentration also had a significant impact on entrainment, primarily through droplet sedimentation feedback rather than through drizzle processes.
Are Changes in Global Precipitation Constrained by the Tropospheric Energy Budget?
Authors: Lambert F. Hugo , Allen Myles R. 
Published: August 2008

AbstractA tropospheric energy budget argument is used to analyze twentieth-century precipitation changes. It is found that global and ocean-mean general circulation model (GCM) precipitation changes can be understood as being due to the competing direct and surface-temperature-dependent effects of external climate forcings. In agreement with previous work, precipitation is found to respond more strongly to anthropogenic and volcanic sulfate aerosol and solar forcing than to greenhouse gas and black carbon aerosol forcing per unit temperature. This is due to the significant direct effects of greenhouse gas and black carbon forcing. Given that the relative importance of different forcings may change in the twenty-first century, the ratio of global precipitation change to global temperature change may be quite different. Differences in GCM twentieth- and twenty-first-century values are tractable via the energy budget framework in some, but not all, models. Changes in land-mean precipitation, on the other hand, cannot be understood at all with the method used here, even if land–ocean heat transfer is considered. In conclusion, the tropospheric energy budget is a useful concept for understanding the precipitation response to different forcings but it does not fully explain precipitation changes even in the global mean.
The Role of Eddies in the Southern Ocean Temperature Response to the Southern Annular Mode
Authors: Screen James A. , Gillett Nathan P. , Stevens David P. , Marshall Gareth J. , Roscoe Howard K. 
Published: August 2008

Abstract
The role of eddies in modulating the Southern Ocean response to the southern annular mode (SAM) is examined, using an ocean model run at multiple resolutions from coarse to eddy resolving. The high-resolution versions of the model show an increase in eddy kinetic energy that peaks 2–3 yr after a positive anomaly in the SAM index. Previous work has shown that the instantaneous temperature response to the SAM is characterized by predominant cooling south of 45°S and warming to the north. At all resolutions the model captures this temperature response. This response is also evident in the coarse-resolution implementation of the model with no eddy mixing parameterization, showing that eddies do not play an important role in the instantaneous response. On the longer time scales, an intensification of the mesoscale eddy field occurs, which causes enhanced poleward heat flux and drives warming south of the oceanic Polar Front. This warming is of greater magnitude and occurs for a longer period than the initial cooling response. The results demonstrate that this warming is surface intensified and strongest in the mixed layer. Non-eddy-resolving models are unable to capture the delayed eddy-driven temperature response to the SAM. The authors therefore question the ability of coarse-resolution models, such as those commonly used in climate simulations, to accurately represent the full impacts of the SAM on the Southern Ocean.
Characterizing and Modeling Temporal and Spatial Trends in Rainfall Extremes
Authors: Aryal Santosh K. , Bates Bryson C. , Campbell Edward P. , Li Yun , Palmer Mark J. , Viney Neil R. 
Published: August 2008

AbstractA hierarchical spatial model for daily rainfall extremes that characterizes their temporal variation due to interannual climatic forcing as well as their spatial pattern is proposed. The model treats the parameters of at-site probability distributions for rainfall extremes as “data” that are likely to be spatially correlated and driven by atmospheric forcing. The method is applied to daily rainfall extremes for summer and winter half years over the Swan–Avon River basin in Western Australia. Two techniques for the characterization of at-site extremes—peaks-over-threshold (POT) analysis and the generalized extreme value (GEV) distribution—and three climatic drivers—the El Niño–Southern Oscillation as measured by the Southern Oscillation index (SOI), the Southern Hemisphere annular mode as measured by an Antarctic Oscillation index (AOI), and solar irradiance (SI)—were considered. The POT analysis of at-site extremes revealed that at-site thresholds lacked spatial coherence, making it difficult to determine a smooth spatial surface for the threshold parameter. In contrast, the GEV-based analysis indicated smooth spatial patterns in daily rainfall extremes that are consistent with the predominant orientation of storm tracks over the study area and the presence of a coastal escarpment near the western edge of the basin. It also indicated a linkage between temporal trends in daily rainfall extremes and those of the SOI and AOI. By applying the spatial models to winter and summer extreme rainfalls separately, an apparent increasing trend in return levels of summer rainfall to the northwest and decreasing trends in return levels of winter rainfall to the southwest of the region are found.
Can Long Meridional Length Scales Yield Faster Rossby Waves?
Authors: Poulin F. J. 
Published: August 2008

Abstract
There is much interest in better understanding the westward-propagating subinertial signal in the ocean basins because it influences many aspects of the ocean’s circulation. One explanation for the origin of this signal is that it is predominantly composed of Rossby waves. Chelton and Schlax assumed the observations were Rossby waves and compared their phase speeds with those predicted from nondispersive linear quasigeostrophic wave speeds. They concluded that the theory underestimated the observed wave speeds. Recently, in the context of the shallow-water model, Paldor, Rubin, and Mariano found that by including the full meridional variation of the Coriolis parameter, the Rossby waves have faster phase speeds. Here, their analysis is extended to derive a general dispersion relation for stratified Rossby waves that is suitable for both mesoscale and synoptic length scales. Then, realistic profiles of the buoyancy frequency are used to compare the phase speeds from the Ocean Topography Experiment (TOPEX)/Poseidon data with the new theory. It is found that the new theory does not yield any significant increase in Rossby wave speeds.
Spectral Coherence and the Statistical Significance of Turbulent Flux Computations
Authors: Biltoft Christopher A. , Pardyjak Eric R. 
Published: August 2008

AbstractThe squared spectral coherence, a frequency-domain analog of the squared correlation coefficient, identifies the frequencies at which two variables most strongly covary. A simple coherence significance test designed to determine whether coherence peaks exceed critical values expected from chance random number correlations is described. This significance test determines the probability with which coherence peaks are likely to arise out of random turbulence. A statistically significant coherence peak also indicates the likely presence of a significant turbulent flux. The test is illustrated using sonic anemometer–thermometer data acquired in an urban setting and over a salt playa. Successful application of this coherence significance test requires selection of a properly sized data record and a Fourier transform with appropriate windowing. The sampling period should be sufficiently long to span major flux-generating scales of motion up to the cross-spectral gap but not so long that extraneous larger scale motions are included. A record length and transform size that yield equivalent degrees of freedom in the range between 10 and 100 produces the most consistent and reliable significance test results.
Links between Tropical Cyclone Activity and Madden–Julian Oscillation Phase in the North Atlantic and Northeast Pacific Basins
Authors: Barrett Bradford S. , Leslie Lance M. 
Published: August 2008

Abstract
The leading intraseasonal mode of atmospheric and oceanic variability, the Madden–Julian oscillation (MJO), influences tropical and extratropical sea level pressure, temperature, divergent and rotational wind components, moisture, and deep convection. As a 40- to 50-day oscillation, the MJO is also known to influence tropical phenomena, including tropical cyclone (TC) activity in various TC basins. The links between the MJO and multiple measures of TC activity, including genesis, landfall, and an integrative accumulated cyclone energy (ACE) index, were quantified for multiple TC-formation basins across the Western Hemisphere, including the North Atlantic and northeast Pacific Ocean and subbasins, for the period 1978–2006. Using this relatively long (29 yr) TC dataset and employing an upper-tropospheric MJO diagnostic that is physically meaningful over the entire Western Hemisphere, this study extends existing research on the relationships between the MJO and TCs. The NOAA Climate Prediction Center’s operational MJO index, derived from 200-hPa velocity potential data, was divided into three phases. Relative frequencies of the MJO phases were compared with observed levels of TC activity using a binomial distribution hypothesis test. The MJO was found to statistically significantly modulate the frequency of TC genesis, intensification, and landfall in the nine TC basins studied. For example, when an MJO index was large and positive at 120°W, hurricanes and intense hurricanes were 4 times as likely to make landfall in the North Atlantic. This modulation of TC activity, including landfall patterns in the North Atlantic, was physically linked to the upper-atmospheric response to the eastward-propagating MJO and is evident as a dipole of TC activity between Pacific and Atlantic subbasins.
Agomelatine, an innovative pharmacological response to unmet needs
Authors: Le Strat Y , Gorwood P 
Published: August 2008

Abstract Most of the available antidepressants, with different pharmacological profiles, such as inhibitors of serotonin reuptake (SSRIs) or norepinephrine reuptake (NRIs) or both (SNRIs), have limitations leading some patients to drop out of treatment. Another direction of research has therefore been undertaken, based initially on the fact that affective disorders are most often characterized by abnormal patterns of circadian rhythms. This consideration has led to the synthesis of agomelatine, a novel antidepressant combining melatonergic MT1 and MT2 agonism and serotonergic 5-HT2C antagonism. The antidepressant effects of agomelatine have been investigated in different animal models, including chronic mild stress, forced swimming, learned helplessness and psychosocial stress. All studies reported an antidepressant-like effect of agomelatine. A resynchronizing activity of agomelatine was seen in animal models for delayed sleep phase syndrome and in several original models of circadian disturbance, such as rodents infected by trypanosome or old hamsters. This activity of agomelatine on circadian rhythms was further confirmed in humans. Furthermore, several randomized, double-blind, placebo-controlled and comparator-controlled studies of agomelatine in the treatment of major depressive disorder indicate that agomelatine is effective and well tolerated.
Arthroscopic Release for Symptomatic Scarring of the Anterior Interval of the Knee
Authors: Steadman J. Richard , Dragoo Jason L. , Hines Sophie L. , Briggs Karen K. 
Published: August 2008

Background Patients with a history of knee trauma or previous surgery may exhibit pain in the infrapatellar region that is refractory to conservative care. This may be due to subtle scarring of the anterior interval. Hypothesis Arthroscopic release of a scarred anterior interval will lead to improvement in anterior knee pain. Study Design Case series; Level of evidence, 4. Methods Twenty-five consecutive patients with isolated scarring of the anterior interval, confirmed with both magnetic resonance imaging (MRI) and arthroscopic examination, were included. All 25 patients had refractory anterior knee pain that was unimproved after a minimum of 6 months of physical therapy and nonsteroidal anti-inflammatory medications and pain during knee extension. All patients had a minimum of 2 previous surgical procedures, and 11 (44%) of the patients had a previous anterior cruciate ligament (ACL) reconstruction. All 25 (100%) patients had an apparent decrease in the cranial excursion of the patella and had a positive Hoffa test result. Fourteen (56%) patients had a preoperative flexion contracture of at least 5°. All patients underwent an isolated arthroscopic anterior interval release. Results All patients were evaluated by physical examination and standardized scoring instruments with an average follow-up of 4.0 years (range, 2.0-7.2). Twenty-one patients had full range of motion of the patella in all directions and a negative Hoffa test finding at final follow-up. All 14 (100%) patients with preoperative flexion contractures (>5°) experienced a full return of extension. The average Lysholm score improved from 59 preoperatively to 81 postoperatively ( P < .0001). The average International Knee Documentation Committee (IKDC) score improved from 49 to 70 ( P < .001). There were no complications. Four patients (16%) had failed results and required a second surgical release. Patients with failures had significantly lower preoperative Lysholm scores (score = 40) than those who did not (score = 58) ( P = .022). Three of the failures were workers’ compensation cases. Conclusion Scarring of the anterior interval changes the mechanics of the anterior structures of the knee and may lead to refractory anterior knee pain. Arthroscopic anterior interval release successfully provides pain relief in this patient population.
Incidence of Anterior Cruciate Ligament Injuries among Elite Ballet and Modern Dancers
Authors: Liederbach Marijeanne , Dilgen Faye E. , Rose Donald J. 
Published: August 2008

Background Ballet and modern dance are jump-intensive activities, but little is known about the incidence of anterior cruciate ligament (ACL) injuries among dancers. Hypothesis Rigorous jump and balance training has been shown in some prospective studies to significantly reduce ACL injury rates among athletes. Dancers advance to the professional level only after having achieved virtuosic jump and balance technique. Therefore, dancers on the elite level may be at relatively low risk for ACL injury. Study Design Descriptive epidemiology study. Methods Dance exposure, injuries, and injury conditions were systematically recorded at 4 dance organizations over 5 years. Select neuromuscular and psychometric variables were compared between and within ACL-injured and noninjured dancers. Results Of 298 dancers, 12 experienced an ACL injury over the 5-year period. The incidence of ACL injury was 0.009 per 1000 exposures. Landing from a jump onto 1 leg was the mechanism of injury in 92% of cases. Incidence was not statistically different between gender or dance groups, although women modern dancers had a 3 to 5 times greater relative risk than women ballet dancers and men dancers. No difference between ACL-injured and noninjured dancers emerged with regard to race, oral contraceptive use, or select musculoskeletal measures. Conclusion Dancers suffer considerably fewer ACL injuries than athletes participating in team ball sports. The training dancers undertake to perfect lower extremity alignment, jump, and balance skills may serve to protect them against ACL injury. Anterior cruciate ligament injuries happened most often late in the day and season, suggesting an effect of fatigue.
Clinical and immunologic consequences of a somatic reversion in a patient with X-linked severe combined immunodeficiency
Authors: Speckmann Carsten , Pannicke Ulrich , Wiech Elisabeth , Schwarz Klaus , Fisch Paul , Friedrich Wilhelm , Niehues Tim , Gilmour Kimberly , Buiting Karin , Schlesier Michael , Eibel Hermann , Rohr Jan , Superti-Furga Andrea , Groß-Wieltsch Ute , Ehl Stephan 
Published: August 2008

Abstract
X-linked severe combined immunodeficiency is a life-threatening disorder caused by mutations in the gene encoding the interleukin-2 receptor gamma chain (IL2RG). Hypomorphic mutations and reversion of mutations in subpopulations of cells can result in variant clinical phenotypes, making diagnosis and treatment difficult. We describe a 5-year-old boy with mild susceptibility to infection who was investigated for a mutation in IL2RG due to persistent natural killer (NK)– and T-cell lymphopenia. A functionally relevant novel T466C point mutation was found in B, NK, and epithelial cells, whereas α/β and γ/δ T cells showed the normal gene sequence, suggesting reversion of the mutation in a common T-cell precursor. This genetic correction in T cells resulted in a diverse T-cell repertoire and significant immunity despite failure to produce specific antibodies linked to an intrinsic defect of mutant B cells. These observations confirm the potential of revertant T-cell precursors to reconstitute immune function, but questions remain on the longevity of revertant cells implicating the need for careful follow up and early consideration of hematopoietic stem cell transplantation (HSCT).