bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Selective Bleed Variable Cycle Engine
Authors: Do Nascimento Marco A. R. , Pilidis Pericles 
Published: March 2015

A new concept in aircraft propulsion is described in this paper. A variable cycle jet engine is being investigated for a supersonic STOVL aircraft. The engine is the selective bleed turbofan, a two shaft three compressor engine. At low flight speeds this engine operates as a medium bypass turbofan, and for the supersonic cruise condition it operates as a low bypass ratio turbofan in the dry mode.
In this paper, the performance of the engine and some of the components is analysed. Off-design engine performance characteristics are explained, compressor running lines are shown, and variable geometry requirements are described.
The performance analysis shows that fuel savings are significant, thus reducing aircraft take-off weight. The major advantage of this engine is that all the components are employed all the time, for all operating modes, thus incurring low weight penalties.
Jet Engine Test System Including Expert System for Diagnosis
Authors: Suzuki K. , Umene K. , Ishizawa H. 
Published: March 2015

A jet engine test run system has been developed which enables automatic engine testing ( functional and performance checks, including engine control trims ). This system includes an expert system for diagnostic procedures which are the result of proper judgements based on experience and knowledge and high speed processing.
In this paper, we describe the construction and an application of the jet engine test equipment and the expert system for jet engine diagnostics.
Pacing Strategy in Short Cycling Time Trials
Authors: de Jong Jelle , van der Meijden Linda , Hamby Simone , Suckow Samantha , Dodge Christopher , de Koning Jos J. , Foster Carl 
Published: March 2015

Purpose:To reach top performance in cycling, optimizing distribution of energy resources is crucial. The purpose of this study was to investigate power output during 250-m, 500-m, and 1000-m cycling time trials and the characteristics of the adopted pacing strategy.Methods:Nine trained cyclists completed an incremental test and 3 time trials that they were instructed to finish as quickly as possible. Preceding the trials, peak power during short sprints (PPsprint) and gross efficiency (GE) were measured. During the trials, power output and oxygen consumption were measured to calculate the contribution of the aerobic and anaerobic energy sources. After the trial GE was measured again.Results:Peak power during all trials (PPTT) was lower than PPsprint. In the 250-m trial the PPTT was higher in the 1000-m trial (P = .008). The subjects performed a significantly longer time at high intensity in the 250-m than in the 1000-m (P = .029). GE declined significantly during all trials (P < .01). Total anaerobically attributable work was less in the 250-m than in the 500-m (P = .015) and 1000-m (P < .01) trials.Conclusion:The overall pacing pattern in the 250-m trial appears to follow an all-out strategy, although peak power is still lower than the potential maximal power output. This suggests that a true all-out pattern of power output may not be used in fixed-distance events. The 500-m and 1000-m had a more conservative pacing pattern and anaerobic power output reached a constant magnitude.
Smartphone-Derived Heart-Rate Variability and Training Load in a Women’s Soccer Team
Authors: Flatt Andrew A. , Esco Michael R. 
Published: March 2015

Purpose:This study evaluated the 7-d mean and coefficient of variation (CV) of supine and standing ultrashort log-transformed root mean square of successive R-R intervals multiplied by 20 (lnRMSSDx20) obtained with a smartphone application (app) in response to varying weekly training load (TL). In addition, the authors aimed to determine if these values could be accurately assessed in as few as 5 or 3 d/wk.Methods:Nine women from a college soccer team performed daily heart-rate-variability measures with an app in supine and standing positions over 3 wk of moderate, high, and low TL. The mean and CV over 7, 5, and 3 d were compared within and between weeks.Results:The 5- and 3-d measures within each week provided very good to nearly perfect intraclass correlations (ICCs .74–.99) with typical errors ranging from 0.64 to 5.65 when compared with the 7-d criteria. The 7, 5, and 3-d supine CV and the 7-day standing CV were moderately lower during the low-load than the high-load week (P .003–.045, effect sizes 0.86–0.92), with no significant changes occurring in the other measures.Conclusion:This study supports the use of the mean and CV of lnRMSSD measured across at least 5 d for reflecting weekly values. The supine lnRMssDx20 CV as measured across 7, 5, and 3 d was the most sensitive marker to the changes in TL in the 3-wk period.
A More Flexible Lipoprotein Sorting Pathway
Authors: Chahales Peter , Thanassi David G. 
Published: March 2015

ABSTRACT

Lipoprotein biogenesis in Gram-negative bacteria occurs by a conserved pathway, each step of which is considered essential. In contrast to this model, LoVullo and colleagues demonstrate that the
N
-acyl transferase Lnt is not required in
Francisella tularensis
or
Neisseria gonorrhoeae
. This suggests the existence of a more flexible lipoprotein pathway, likely due to a modified Lol transporter complex, and raises the possibility that pathogens may regulate lipoprotein processing to modulate interactions with the host.
Oral focal mucinosis: a rare case with literature review
Authors: Sowmya G V , Manjunatha Bhari Sharanesha , Nahar Prashant , Aggarwal Hersheal 
Published: March 2015

Oral focal mucinosis (OFM) is an unusual disease that affects diverse localised areas of the mouth, where the connective tissue undergoes focal degeneration. It was described for the first time by Tomich in 1974. It presents as an asymptomatic pedunculated or sessile growth, commonly on the gingiva, with most cases being in women. Its pathogenesis is linked to overproduction of hyaluronic acid by fibroblasts during collagen production, ensuing in focal myxoid degeneration. It has no characteristic features and diagnosis depends on histological scrutiny. We report a rare case of oral focal mucinosis affecting a 54-year-old man who presented with a sessile gingival growth mimicking a common tumour-like lesion.
Demonstration of a GOES-R Satellite Convective Toolkit to “Bridge the Gap” between Severe Weather Watches and Warnings: An Example from the 20 May 2013 Moore, Oklahoma, Tornado Outbreak
Authors: Gravelle Chad M. , Mecikalski John R. , Line William E. , Bedka Kristopher M. , Petersen Ralph A. , Sieglaff Justin M. , Stano Geoffrey T. , Goodman Steven J. 
Published: March 2015

Abstract
With the launch of the Geostationary Operational Environmental Satellite–R (GOES-R) series in 2016, there will be continuity of observations for the current GOES system operating over the Western Hemisphere. The GOES-R Proving Ground was established in 2008 to help prepare satellite user communities for the enhanced capabilities of GOES-R, including new instruments, imagery, and products that will have increased spectral, spatial, and temporal resolution. This is accomplished through demonstration and evaluation of proxy products that use current GOES data, higher-resolution data provided by polar-orbiting satellites, and model-derived synthetic satellite imagery. The GOES-R demonstration products presented here, made available to forecasters in near–real time (within 20 min) via the GOES-R Proving Ground, include the 0–9-h NearCast model, 0–1-h convective initiation probabilities, convective cloud-top cooling, overshooting top detection, and a pseudo–Geostationary Lightning Mapper total lightning tendency diagnostic. These products are designed to assist in identifying areas of increasing convective instability, pre-radar echo cumulus cloud growth preceding thunderstorm formation, storm updraft intensity, and potential storm severity derived from lightning trends. In turn, they provide the warning forecaster with improved situational awareness and short-term predictive information that enhance their ability to monitor atmospheric conditions preceding and associated with the development of deep convection, a time period that typically occurs between the issuance of National Weather Service (NWS) Storm Prediction Center convective watches and convective storm warnings issued by NWS forecast offices. This paper will focus on how this GOES-R satellite convective toolkit could have been used by warning forecasters to enhance near-storm environment analysis and the warning-decision-making process prior to and during the 20 May 2013 Moore, Oklahoma, tornado event.
Searching for Large Raindrops: A Global Summary of Two-Dimensional Video Disdrometer Observations
Authors: Gatlin Patrick N. , Thurai Merhala , Bringi V. N. , Petersen Walter , Wolff David , Tokay Ali , Carey Lawrence , Wingo Matthew 
Published: March 2015

AbstractA dataset containing 9637 h of two-dimensional video disdrometer observations consisting of more than 240 million raindrops measured at diverse climatological locations was compiled to help characterize underlying drop size distribution (DSD) assumptions that are essential to make precise retrievals of rainfall using remote sensing platforms. This study concentrates on the tail of the DSD, which largely impacts rainfall retrieval algorithms that utilize radar reflectivity. The maximum raindrop diameter was a median factor of 1.8 larger than the mass-weighted mean diameter and increased with rainfall rate. Only 0.4% of the 1-min DSD spectra were found to contain large raindrops exceeding 5 mm in diameter. Large raindrops were most abundant at the tropical locations, especially in Puerto Rico, and were largely concentrated during the spring, especially at subtropical locations. Giant raindrops exceeding 8 mm in diameter occurred at tropical, subtropical, and high-latitude continental locations. The greatest numbers of giant raindrops were found in the subtropical locations, with the largest being a 9.7-mm raindrop that occurred in northern Oklahoma during the passage of a hail-producing thunderstorm. These results suggest large raindrops are more likely to fall from clouds that contain hail, especially those raindrops exceeding 8 mm in diameter.
A Link between the Hiatus in Global Warming and North American Drought
Authors: Delworth Thomas L. , Zeng Fanrong , Rosati Anthony , Vecchi Gabriel A. , Wittenberg Andrew T. 
Published: March 2015

Abstract
Portions of western North America have experienced prolonged drought over the last decade. This drought has occurred at the same time as the global warming hiatus—a decadal period with little increase in global mean surface temperature. Climate models and observational analyses are used to clarify the dual role of recent tropical Pacific changes in driving both the global warming hiatus and North American drought. When observed tropical Pacific wind stress anomalies are inserted into coupled models, the simulations produce persistent negative sea surface temperature anomalies in the eastern tropical Pacific, a hiatus in global warming, and drought over North America driven by SST-induced atmospheric circulation anomalies. In the simulations herein the tropical wind anomalies account for 92% of the simulated North American drought during the recent decade, with 8% from anthropogenic radiative forcing changes. This suggests that anthropogenic radiative forcing is not the dominant driver of the current drought, unless the wind changes themselves are driven by anthropogenic radiative forcing. The anomalous tropical winds could also originate from coupled interactions in the tropical Pacific or from forcing outside the tropical Pacific. The model experiments suggest that if the tropical winds were to return to climatological conditions, then the recent tendency toward North American drought would diminish. Alternatively, if the anomalous tropical winds were to persist, then the impact on North American drought would continue; however, the impact of the enhanced Pacific easterlies on global temperature diminishes after a decade or two due to a surface reemergence of warmer water that was initially subducted into the ocean interior.
How Climate Model Complexity Influences Sea Ice Stability
Authors: Wagner Till J. W. , Eisenman Ian 
Published: March 2015

AbstractRecord lows in Arctic sea ice extent have been making frequent headlines in recent years. The change in albedo when sea ice is replaced by open water introduces a nonlinearity that has sparked an ongoing debate about the stability of the Arctic sea ice cover and the possibility of Arctic “tipping points.” Previous studies identified instabilities for a shrinking ice cover in two types of idealized climate models: (i) annual-mean latitudinally varying diffusive energy balance models (EBMs) and (ii) seasonally varying single-column models (SCMs). The instabilities in these low-order models stand in contrast with results from comprehensive global climate models (GCMs), which typically do not simulate any such instability. To help bridge the gap between low-order models and GCMs, an idealized model is developed that includes both latitudinal and seasonal variations. The model reduces to a standard EBM or SCM as limiting cases in the parameter space, thus reconciling the two previous lines of research. It is found that the stability of the ice cover vastly increases with the inclusion of spatial communication via meridional heat transport or a seasonal cycle in solar forcing, being most stable when both are included. If the associated parameters are set to values that correspond to the current climate, the ice retreat is reversible and there is no instability when the climate is warmed. The two parameters have to be reduced by at least a factor of 3 for instability to occur. This implies that the sea ice cover may be substantially more stable than has been suggested in previous idealized modeling studies.
Intercomparison of Attenuation Correction Methods for the GPM Dual-Frequency Precipitation Radar
Authors: Seto Shinta , Iguchi Toshio 
Published: March 2015

AbstractA new attenuation correction method has been developed for the dual-frequency precipitation radar (DPR) on the core satellite of the Global Precipitation Measurement (GPM) mission. The new method is based on Hitschfeld and Bordan’s attenuation correction method (HB method), but the relationship between the specific attenuation k and the effective radar reflectivity factor Ze (k–Ze relationship) is modified by using the dual-frequency ratio (DFR) of Ze and the surface reference technique (SRT). Therefore, the new method is called the HB-DFR-SRT method (H-D-S method). The previous attenuation correction method, called the HB-DFR method (H-D method), results in an underestimation of precipitation rates for heavy precipitation, but the H-D-S method mitigates the negative bias by means of the SRT. When only a single-frequency measurement is available, the H-D-S method is identical to the HB-SRT method (H-S method).The attenuation correction methods were tested with a simple synthetic DPR dataset. As long as the SRT gives perfect estimates of path-integrated attenuation and the adjustment factor of the k–Ze relationship (denoted by ε) is vertically constant, the H-S method is much better than the dual-frequency methods. Tests with SRT error and vertical variation in ε showed that the H-D method was better than the H-S method for weak precipitation, whereas the H-S method was better than the H-D method for heavy precipitation. The H-D-S method did not produce the best results for both weak and heavy precipitation, but the results are stable. Quantitative evaluation should be done with real DPR measurement datasets.
Harmonic Analysis in the Simulation of Multiple Constituents: Determination of the Optimum Length of Time Series
Authors: Cao An-Zhou , Wang Dao-Sheng , Lv Xian-Qing 
Published: March 2015

AbstractTo investigate the optimum length of time series (TS) for harmonic analysis (HA) in the simulation of multiple constituents, a two-dimensional tidal model is used to simulate the M2, S2, K1, and O1 constituents in the Bohai and Yellow Seas. By analyzing the HA results of several nonoverlapping TS of the same length, which varies from 15 to 365 days, a field-average deviation of HA results is calculated. A deviation that is sufficiently small means that HA results are independent of the choice of TS, and the corresponding TS length is regarded as the optimum. Results indicate that the range of 180–195 days is the optimum length of TS for HA in the simulation of the four principal constituents. To investigate what determines the optimum length, experiments with different computed area and model settings are carried out. Results indicate that the optimum length is independent of advection, nodal corrections, and computed area, and only depends on bottom friction. Nonlinear bottom friction results in the appearance of higher harmonics and explains why the optimum length of TS for HA is 180–195 days.
Adaptive Localization for the Ensemble-Based Observation Impact Estimate Using Regression Confidence Factors
Authors: Gasperoni Nicholas A. , Wang Xuguang 
Published: March 2015

Abstract
The goal of this study is to improve an ensemble-based estimation for forecast sensitivity to observations that is straightforward to apply using existing products of any ensemble data assimilation system. Because of limited ensemble sizes compared to the large degrees of freedom in typical models, it is necessary to apply localization techniques to obtain accurate estimates. Fixed localization techniques do not guarantee accurate impact estimates, because as forecast time increases the error correlation structures evolve with the flow. Here a dynamical localization method is applied to improve the observation impact estimate. The authors employ a Monte Carlo “group filter” technique to limit the effects of sampling error via regression confidence factor (RCF). Experiments make use of the local ensemble transform Kalman filter (LETKF) with a simple two-layer primitive equation model and simulated observations. Results show that the shape, location, time dependency, and variable dependency of RCF localization functions are consistent with underlying dynamical processes of the model. Application of RCF localization to ensemble-estimated impact showed marked improvement especially for longer forecasts and at midlatitudes, when systematically verified against actual impact in RMSE and skill scores. The impact estimates near the equator were not as effective because of large discrepancies between the RCF function and the localization used at assimilation time. These latter results indicate that there exists an inherent relationship between the localization applied during the assimilation time and the proper localization choice for observation impact estimates. Application of RCF for automatically tuned localization is introduced and tested for a single observation experiment.
Multivariate Ensemble Sensitivity with Localization
Authors: Hacker Joshua P. , Lei Lili 
Published: March 2015

Abstract
Ensemble sensitivities have proven a useful alternative to adjoint sensitivities for large-scale dynamics, but their performance in multiscale flows has not been thoroughly examined. When computing sensitivities, the analysis covariance is usually approximated with the corresponding diagonal matrix, leading to a simple univariate regression problem rather than a more general multivariate regression problem. Sensitivity estimates are affected by sampling error arising from a finite ensemble and can lead to an overestimated response to an analysis perturbation. When forecasts depend on many details of an analysis, it is reasonable to expect that the diagonal approximation is too severe. Because spurious covariances are more likely when correlations are weak, computing the sensitivity with a multivariate regression that retains the full analysis covariance may increase the need for sampling error mitigation. The purpose of this work is to clarify the effects of the diagonal approximation, and investigate the need for mitigating spurious covariances arising from sampling error. A two-scale model with realistic spatial covariances is the basis for experimentation. For most problems, an efficient matrix inversion is possible by finding a minimum-norm solution, and employing appropriate matrix factorization. A published hierarchical approach for estimating regression factors for tapering (localizing) covariances is used to measure the effects of sampling error. Compared to univariate regressions in the diagonal approximation, skill in predicting a nonlinear response from the linear sensitivities is superior when localized multivariate sensitivities are used, particularly when fast scales are present, model error is present, and the observing network is sparse.
Reduction of Bone Dust with Ultrasonic Bone Aspiration
Authors: Weber Jon D. , Samy Ravi N. , Nahata Amit , Zuccarello Mario , Pensak Myles L. , Golub Justin S. 
Published: March 2015

ObjectivePostoperative headache is not uncommon after retrosigmoid vestibular schwannoma removal. Bone dust dispersed into the subarachnoid space during drilling may be responsible. If dispersion could be reduced, headache incidence might be decreased. An ultrasonic bone aspirator (UBA) containing an integrated suction at the tip may more effectively suction bone dust created during bone removal. The objective is to determine whether a UBA results in less bone dust dispersion than a standard otologic drill.Study DesignCadaveric temporal bone quantitative model.SettingLaboratory.Subjects and MethodsTemporal bone blocks were placed in a watertight enclosure. Under irrigation, bone was removed by use of either a drill or a UBA. The settings of the UBA were varied. The irrigant containing bone dust was microfiltered, and bone dust was weighed. Differences were compared across groups (n = 2‐9 per group). Ablation times were also recorded (n = 3 per group).ResultsOnly 3% (SD = 1.6%, n = 7) of the drilled bone mass was re‐collected as bone dust with the UBA under optimized settings (power = 15%, suction = 100%, irrigation = 15 mL/min) compared with 81% (SD = 10%, n = 4) with the drill and external suction (P <. 001). Increasing UBA power and reducing suction led to significantly more bone dust dispersal than with optimized settings. Varying irrigation did not have a significant effect. Bone ablation time was 1.4 times longer with the UBA at 50% power compared with the drill at maximum power.ConclusionsThe UBA resulted in approximately 25 times less bone dust dispersion than the otologic drill at optimized settings.
The efficacy of fat emulsion and normal saline for bile leakage tests during hepatic resection: A randomized trial
Authors: Liu Ming , Liu Zhiyi , Jin Hu , Jiao Yonggeng 
Published: March 2015

Objective A randomized controlled trial to evaluate the use of fat emulsion and normal saline for bile leakage tests during hepatic resection. Methods Patients were randomized to undergo intraoperative bile leakage tests with saline then fat emulsion (Group A), or fat emulsion then saline (Group B). All patients received both tests. Results In group A ( n = 64), saline revealed 53 leakage points in 27 patients, and fat emulsion revealed 42 additional points in a further nine patients. In group B ( n = 64), fat emulsion revealed 87 leakage points in 37 patients, and saline revealed three additional points in three patients. There were no significant between-group differences in the number of leakage points detected by the first test, total number of leakage points or postoperative complications. Significantly more leakage points were detected by the second test in Group A (fat emulsion) than in Group B (saline). Conclusions Fat emulsion then saline identifies more leakage points after the first test than saline then fat emulsion. There is no difference in the total number of leakage points detected, regardless of which method is used first.