bluuebunny/crossref_metadata_2025_split huggingface dataset:
Full Activation of
Enterococcus faecalis
Gelatinase by a C-Terminal Proteolytic Cleavage
Authors: Del Papa Maria Florencia , Hancock Lynn E. , Thomas Vinai C. , Perego Marta 
Published: October 2007

ABSTRACT

Enterococci account for nearly 10% of all nosocomial infections and constitute a significant treatment challenge due to their multidrug resistance properties. One of the well-studied virulence factors of
Enterococcus faecalis
is a secreted bacterial protease, termed gelatinase, which has been shown to contribute to the process of biofilm formation. Gelatinase belongs to the M4 family of bacterial zinc metalloendopeptidases, typified by thermolysin. Gelatinase is synthesized as a preproenzyme consisting of a signal sequence, a putative propeptide, and then the mature enzyme. We determined that the molecular mass of the mature protein isolated from culture supernatant was 33,030 Da, which differed from the predicted molecular mass, 34,570 Da, by over 1,500 Da. Using N-terminal sequencing, we confirmed that the mature protein begins at the previously identified sequence VGSEV, thus suggesting that the 1,500-Da molecular mass difference resulted from a C-terminal processing event. By using mutants with site-directed mutations within a predicted C-terminal processing site and mutants with C-terminal deletions fused to a hexahistidine tag, we determined that the processing site is likely to be between residues D304 and I305 and that it requires the Q306 residue. The results suggest that the
E. faecalis
gelatinase requires C-terminal processing for full activation of protease activity, making it a unique enzyme among the members of the M4 family of proteases of gram-positive bacteria.
Transposon Tn
7
Directs Transposition into the Genome of Filamentous Bacteriophage M13 Using the Element-Encoded TnsE Protein
Authors: Finn Jessica A. , Parks Adam R. , Peters Joseph E. 
Published: October 2007

ABSTRACT

The bacterial transposon Tn
7
has a pathway of transposition that preferentially targets conjugal plasmids. We propose that this same transposition pathway recognizes a structure or complex found during filamentous bacteriophage replication, likely by targeting negative-strand synthesis. The ability to insert into both plasmid and bacteriophage DNAs that are capable of cell-to-cell transfer would help explain the wide distribution of Tn
7
relatives.
Voice Register in Khmu’: Experiments in Production and Perception
Authors: Abramson Arthur S. , Nye Patrick W. , Luangthongkum Theraphan 
Published: October 2007

AbstractSome Khmu’ dialects have phonologically distinctive voice registers.Auditory observations have claimed a stable distinction between clear voice andhigh pitch for Register 1 and breathy voice and low pitch for Register 2 in theKhmu’ Rawk dialect of northern Thailand. Word pairs distinguished only by registerwere recorded by 25 native speakers. Acoustic analysis yielded F0 and overallamplitude contours, frequencies of F1 and F2 in quasi-steady states of the vowels,relative intensities of higher harmonics to that of the first harmonic, and voweldurations. When circumstances caused early attention to perception testing, thewords of only 8 speakers had been analyzed for properties other than amplitudeand F0. Since the only significant factor that had emerged by then was F0 contour,the synthetic stimuli were made with just a series of seven contours. The labelingby 32 native speakers yielded two categories, demonstrating the sufficiency of F0as an acoustic cue. The completed acoustic analysis showed a significant effect ofone of the harmonic ratios for the women only, suggesting a conservative bias.The language has been shifting toward tonality and may have reached it.
Effects of Acoustic Variability in the Perceptual Learning of Non-Native-Accented Speech Sounds
Authors: Wade Travis , Jongman Allard , Sereno Joan 
Published: October 2007

AbstractThis study addressed whether acoustic variability and category overlap innon-native speech contribute to difficulty in its recognition, and more generallywhether the benefits of exposure to acoustic variability during categorizationtraining are stable across differences in category confusability. Three experimentsconsidered a set of Spanish-accented English productions. The set was seen topose learning and recognition difficulty (experiment 1) and was more variable andconfusable than a parallel set of native productions (experiment 2). A trainingstudy (experiment 3) probed the relative contributions of category central tendencyand variability to difficulty in vowel identification using derived inventoriesin which these dimensions were manipulated based on the results of experiments1 and 2. Training and test difficulty related straightforwardly to category confusabilitybut not to location in the vowel space. Benefits of high-variability exposurealso varied across vowel categories, and seemed to be diminished for highly confusablevowels. Overall, variability was implicated in perception and learning difficultyin ways that warrant further investigation.
Quantitative Ice Accretion Information from the Automated Surface Observing System
Authors: Ryerson Charles C. , Ramsay Allan C. 
Published: October 2007

Abstract
Freezing precipitation is a persistent winter weather problem that costs the United States millions of dollars annually. Costs and infrastructure disruption may be greatly reduced by ice-storm warnings issued by the National Weather Service (NWS), and by the development of climatologies that allow improved design of infrastructure elements. However, neither the NWS nor developers of climatologies have had direct measurements of ice-storm accumulations as a basis for issuing warnings and developing storm design standards. This paper describes the development of an aviation routine/special weather report (METAR/SPECI) remark that will report quantitative ice thickness at over 650 locations during ice storms using new algorithms developed for the Automated Surface Observing System (ASOS). Characteristics of the ASOS icing sensor, a field program to develop the algorithms, tests of accuracy, application of the algorithms, and sources of error are described, as is the implementation of an ice-thickness METAR/SPECI remark. The algorithms will potentially allow freezing precipitation events to be tracked with regard to ice accumulation in near–real time as they progress across the United States.
Uncertainties in Air Toxics Calculated by the Dispersion Models AERMOD and ISCST3 in the Houston Ship Channel Area
Authors: Hanna Steven R. , Paine Robert , Heinold David , Kintigh Elizabeth , Baker Dan 
Published: October 2007

Abstract
The uncertainties in simulations of annually averaged concentrations of two air toxics (benzene and 1,3-butadiene) are estimated for two widely used U.S. air quality models, the Industrial Source Complex Short-Term, version 3, (ISCST3) model and the American Meteorological Society–Environmental Protection Agency Model (AERMOD). The effects of uncertainties in emissions input, meteorological input, and dispersion model parameters are investigated using Monte Carlo probabilistic uncertainty methods, which involve simultaneous random and independent perturbations of all inputs. The focus is on a 15 km × 15 km domain in the Houston, Texas, ship channel area. Concentrations are calculated at hypothetical receptors located at the centroids of population census tracts. The model outputs that are analyzed are the maximum annually averaged maximum concentration at any single census tract or monitor as well as the annually averaged concentration averaged over the census tracts. The input emissions uncertainties are estimated to be about a factor of 3 (i.e., covering the 95% range) for each of several major categories. The uncertainties in meteorological inputs (such as wind speed) and dispersion model parameters (such as the vertical dispersion coefficient σz) also are estimated. The results show that the 95% range in predicted annually averaged concentrations is about a factor of 2–3 for the air toxics, with little variation by model. The input variables whose variations have the strongest effect on the predicted concentrations are on-road mobile sources and some industrial sources (dependent on chemical), as well as wind speed, surface roughness, and σz. In most scenarios, the uncertainties of the emissions input group contribute more to the total uncertainty than do the uncertainties of the meteorological/dispersion input group.
A Robust Numerical Solution of the Stochastic Collection–Breakup Equation for Warm Rain
Authors: Prat Olivier P. , Barros Ana P. 
Published: October 2007

Abstract
The focus of this paper is on the numerical solution of the stochastic collection equation–stochastic breakup equation (SCE–SBE) describing the evolution of raindrop spectra in warm rain. The drop size distribution (DSD) is discretized using the fixed-pivot scheme proposed by Kumar and Ramkrishna, and new discrete equations for solving collision breakup are presented. The model is evaluated using established coalescence and breakup parameterizations (kernels) available in the literature, and in that regard this paper provides a substantial review of the relevant science. The challenges posed by the need to achieve stable and accurate numerical solutions of the SCE–SBE are examined in detail. In particular, this paper focuses on the impact of varying the shape of the initial DSD on the equilibrium solution of the SCE–SBE for a wide range of rain rates and breakup kernels. The results show that, although there is no dependence of the equilibrium DSD on initial conditions for the same rain rate and breakup kernel, there is large variation in the time that it takes to reach steady state. This result suggests that, in coupled simulations of in-cloud motions and microphysics and for short time scales (&lt;30 min) for which transient conditions prevail, the equilibrium DSD may not be attainable except for very heavy rainfall. Furthermore, simulations for the same initial conditions show a strong dependence of the dynamic evolution of the DSD on the breakup parameterization. The implication of this result is that, before the debate on the uniqueness of the shape of the equilibrium DSD can be settled, there is critical need for fundamental research including laboratory experiments to improve understanding of collisional mechanisms in DSD evolution.
Sensitivity of a Mesoscale Model to Microphysical Parameterizations in the MAP SOP Events IOP2b and IOP8
Authors: Serafin Stefano , Ferretti Rossella 
Published: October 2007

Abstract
The sensitivity of a mesoscale model to different microphysical parameterizations is investigated for two events of precipitation in the Mediterranean region, that is, the Mesoscale Alpine Program (MAP) intensive observation periods (IOP) 2b (19–21 September 1999) and 8 (20–22 October 1999). Simulations are performed with the fifth-generation Pennsylvania State University–National Center for Atmospheric Research Mesoscale Model (MM5); the most commonly used bulk microphysical parameterization schemes are evaluated, with a particular focus on their impact on the forecast of rainfall. To evaluate the forecast skill, the verification is carried out quantitatively by using the observations recorded by a high-resolution rain gauge network during the MAP campaign. The results show that, for the surface rainfall forecast, all microphysical schemes produce a similar precipitation field and none of them perform significantly better than the others. The ability of different schemes to reproduce events with different ongoing microphysical processes is briefly discussed by comparing model simulations and knowledge of hydrometeor fields from radar observations. The vertical profiles of hydrometeors from two of the analyzed schemes show gross similarities with available radar observations. Last, the role of one of the parameterizations appearing in a typical bulk microphysical scheme, that is, the one of the snowfall speed, is evaluated in detail. Adjustments in the semiempirical relationships describing the fall speed of snow particles have a large impact, because a reduced snowfall speed enhances precipitation on the lee side of mountain ridges and diminishes it on the windward side. Anyway, this effect does not appear to be able to largely improve or reduce the forecast skill of the MM5 systematically; the impact of changes in the parameterization of the snow deposition velocity very likely depends on the dynamics of the event under investigation.
Diagnosis of the Forcing and Structure of the Coastal Jet near Cape Mendocino Using In Situ Observations and Numerical Simulations
Authors: Rahn David A. , Parish Thomas R. 
Published: October 2007

Abstract
Several flights were conducted by the University of Wyoming King Air near Cape Mendocino, California, during June 2004 to examine finescale features of the coastal low-level jet (CJ) that frequently forms during summer over the ocean off the West Coast of the United States. The primary goal of these flights was to measure the horizontal pressure gradient force (PGF) and hence to determine the forcing of the CJ directly. By flying a series of redundant legs on an isobaric surface, heights of the pressure surface can be obtained from radar altimeter measurements and refined position estimates from an onboard global positioning system receiver. The slope of the isobaric surface height is proportional to the PGF. Results are shown for the 22 June 2004 case study conducted to the south of Cape Mendocino. The forcing of a CJ under weak synoptic forcing and the role of the elevated terrain near Cape Mendocino are explored. Ten isobaric legs approximately 70 km in length and directed east–west were conducted near the level of the maximum CJ wind speed. The vertical structure of the CJ was obtained from sawtooth legs conducted along an east–west flight leg. Numerical simulations have been performed for this case using the fifth-generation Pennsylvania State University–National Center for Atmospheric Research Mesoscale Model (MM5) for comparison with in situ measurements. Model simulations show pressure perturbations in the vicinity of the cape as the northerly winds associated with the CJ interact with the coastal topography. Close agreement is found between in situ measurements and MM5 analyses of the various state parameters and the PGF along the east–west flight track in the lee of Cape Mendocino. Strong variation in the PGF is observed along the flight path. Large ageostrophic accelerations are present in response to the adjustment of the CJ with Cape Mendocino, reflecting the force imbalance between the observed PGF and Coriolis force.
Wind Profiler Observations over the Central Equatorial Pacific: Optimizing Processing to Improve Quality and Height Coverage
Authors: Schafer Robert , Avery Susan K. , Gage Kenneth S. , Kiladis George N. 
Published: October 2007

Abstract
UHF (boundary layer) and VHF (troposphere–stratosphere) wind profilers have operated at Christmas Island (2°N, 157°W) in the central equatorial Pacific from 1986 to 2002. Observed profiles of winds are sparse over the tropical oceans, but these are critical for understanding convective organization and the interaction of convection and waves. While the zonal winds below about 10 km have previously shown good agreement with the National Centers for Environmental Prediction–National Center for Atmospheric Research (NCEP–NCAR) reanalysis (RI), significant differences were found above a height of 10 km that were attributed to the low detectability of the wind signal in the profiler observations. Meridional winds at all levels show less agreement, with differences attributed to errors of representativeness and the sparseness of observations in the region. This paper builds on previous work using the Christmas Island wind profilers and presents the results of reprocessing the 17-yr profiler record with techniques that enhance the detectability of the signal at upper heights. The results are compared with nearby rawinsonde soundings obtained during a special campaign at Christmas Island and the RI, NCEP–Department of Energy (DOE) reanalysis (RII), and the 40-yr European Centre for Medium-Range Weather Forecasts (ECMWF) Re-Analysis (ERA-40). The newly processed profiler zonal and meridional wind observations show good agreement with rawinsonde observations from 0.5 to 19 km above sea level, with difference statistics similar to other studies. There is also significant improvement in the agreement of RI and RII reanalysis and profiler upper-level zonal and meridional winds from previous studies. A comparison of RII and ERA-40 reanalysis shows that difference statistics between the reanalyses are similar in magnitude to differences between the profiler and the individual reanalyses.
IAPSO Standard Seawater: Definition of the Uncertainty in the Calibration Procedure, and Stability of Recent Batches
Authors: Bacon Sheldon , Culkin Fred , Higgs Nigel , Ridout Paul 
Published: October 2007

Abstract
Standard seawater (SSW) has been employed by oceanographers as a reference material in the determination of salinity for over a century. In all that time, this is the first study to determine the uncertainty of the SSW manufacturing process. SSW is calibrated in reference to carefully prepared solutions of potassium chloride (KCl). All uncertainties in the preparation and measurement of KCl solutions and of new SSW are calculated. The expanded uncertainty of the SSW conductivity ratio is found to be 1 × 10−5, based on a coverage factor of 2, at the time of manufacture. There is no discernible “within batch” variability. No significant variability of quality within or between batches of KCl is found. Measurement of SSW “offsets” from the label conductivity ratio as long as 5 yr after the SSW batch manufacture are reported, and no significant change in label conductivity ratio for SSW batches P130 through P144 outside the expanded uncertainty of 1 × 10−5 is found. This last result is in contrast to some other studies, and herein are suggestions as to why this may be the case.
Comparison of In Situ and Satellite-Derived Sea Surface Temperatures in the Gulf of Carpentaria
Authors: Barton Ian J. 
Published: October 2007

AbstractDuring 30 days in May and June 2003, the R/V Southern Surveyor was operating in the Gulf of Carpentaria, northern Australia. Measurements of sea surface temperature (SST) were made with an accurate single-channel infrared radiometer as well as with the ship’s thermosalinograph. These ship-based measurements have been used to assess the quality of the SST derived from nine satellite-borne instruments. The satellite dataset compiled during this period also allows the intercomparison of satellite-derived SST fields in areas not covered by the ship’s track. An assessment of the SST quality from each satellite instrument is presented, and suggestions for blending ground and satellite measurements into a single product are made. These suggestions are directly applicable to the international Global Ocean Data Assimilation Experiment (GODAE) High Resolution SST Pilot Project (GHRSST-PP) that is currently developing an operational system to provide 6-hourly global fields of SST at a spatial resolution close to 10 km. The paper demonstrates how the Diagnostic Datasets (DDSs) and Matchup Database (MDB) of the GHRSST-PP can be used to monitor the quality of individual and blended SST datasets. Recommendations for future satellite missions that are critical to the long-term generation of accurate blended SST datasets are included.
An FPGA-Based Doppler Processor for a Spaceborne Precipitation Radar
Authors: Durden S. L. , Fischman M. A. , Johnson R. A. , Chu A. J. , Jourdan M. N. , Tanelli S. 
Published: October 2007

Abstract
Measurement of precipitation Doppler velocity by spaceborne radar is complicated by the large velocity of the satellite platform. Even if successive pulses are well correlated, the velocity measurement may be biased if the precipitation target does not uniformly fill the radar footprint. It has been previously shown that the bias in such situations can be reduced if full spectral processing is used. The authors present a processor based on field-programmable gate array (FPGA) technology that can be used for spectral processing of data acquired by future spaceborne precipitation radars. The requirements for and design of the Doppler processor are addressed. Simulation and laboratory test results show that the processor can meet real-time constraints while easily fitting in a single FPGA.
Use of a Large Crane for Wind and Tracer Profiles in an Urban Setting
Authors: Gouveia Frank J. , Leach Martin J. , Shinn Joseph H. , Ralph William E. 
Published: October 2007

Abstract
Although measured vertical profiles of wind, turbulence, and tracer concentrations are critical for understanding the urban boundary layer, it is problematic to field a sounding system or a tall structure to support anemometers in a densely populated area. Anemometers mounted on an existing building may be measuring flow distorted by that building. During the Joint Urban 2003 field experiment in Oklahoma City, the authors solved these problems by using a large crane to support a cable and crossarm framework holding a vertical array of eight 3D sonic anemometers. The highest level was over 80 m above the surface; the lowest was just under 8 m. The open-lattice structure of the crane boom and skeletal array framework did not substantially alter the airflow to the sensors. Review of the spectra shows that there are no consistent oscillations in the wind data. Data were accepted from all azimuths, although the flow was from the south 80% of the time. Profiles of wind show pronounced curvature, indicating that the higher levels may be affected by rougher surfaces at a great distance from the crane. This crane-lofted system was safely erected and disassembled in a few hours, stood undisturbed for 34 days, and collected over 1500 separate profiles of 30-min averages.
Neuromuscular and Lower Limb Biomechanical Differences Exist between Male and Female Elite Adolescent Soccer Players during an Unanticipated Side-cut Maneuver
Authors: Landry Scott C. , McKean Kelly A. , Hubley-Kozey Cheryl L. , Stanish William D. , Deluzio Kevin J. 
Published: October 2007

Background Female athletes are 2 to 8 times more likely than male athletes to injure the anterior cruciate ligament during a noncontact athletic maneuver. Identifying anterior cruciate ligament injury risk factors in female athletes may help with the development of preventive training programs aimed at reducing injury rates. Hypothesis Differences between genders in lower limb kinematics, kinetics, and neuromuscular patterns will be identified in an adolescent soccer population during an unanticipated side-cut maneuver. Study Design Controlled laboratory study. Methods Forty-two elite adolescent soccer players (21 male and 21 female) performed an unanticipated side-cut maneuver, with the 3-dimensional kinematic, kinetic, and electromyographic lower limb data being analyzed using principal component analysis. Results The female athletes had higher gastrocnemius activity, normalized to maximal voluntary isometric contractions, and a mediolateral gastrocnemius activation imbalance that was not present in the male athletes during early stance to midstance of the side-cut. Female athletes demonstrated greater rectus femoris muscle activity throughout stance, and the only hamstring difference identified was a mediolateral activation imbalance in male athletes only. Female athletes performed the side-cut with less hip flexion and more hip external rotation and also generated a smaller hip flexion moment compared with the male athletes. Conclusion This is the first study to identify gender-related differences in gastrocnemius muscle activity during an unanticipated cutting maneuver. Clinical Relevance The increased and imbalanced gastrocnemius muscle activity, combined with increased rectus femoris muscle activity and reduced hip flexion angles and moments in female subjects, may all have important contributing roles in the higher noncontact ACL injury rates observed in female athletes.