bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reasons for hospitalization in HIV‐infected children in West Africa
Authors: Dicko Fatoumata , Desmonde Sophie , Koumakpai Sikiratou , Dior‐Mbodj Hélène , Kouéta Fla , Baeta Novisi , Koné Niaboula , Akakpo Jocelyn , Sy Haby Signate , Ye Diarra , Renner Lorna , Lewden Charlotte , Leroy Valériane ,   for the Pediatric IeDEA West Africa Working Group
Published: April 2014

IntroductionCurrent knowledge on morbidity and mortality in HIV‐infected children comes from data collected in specific research programmes, which may offer a different standard of care compared to routine care. We described hospitalization data within a large observational cohort of HIV‐infected children in West Africa (IeDEA West Africa collaboration).MethodsWe performed a six‐month prospective multicentre survey from April to October 2010 in five HIV‐specialized paediatric hospital wards in Ouagadougou, Accra, Cotonou, Dakar and Bamako. Baseline and follow‐up data during hospitalization were recorded using a standardized clinical form, and extracted from hospitalization files and local databases. Event validation committees reviewed diagnoses within each centre. HIV‐related events were defined according to the WHO definitions.ResultsFrom April to October 2010, 155 HIV‐infected children were hospitalized; median age was 3 years [1–8]. Among them, 90 (58%) were confirmed for HIV infection during their stay; 138 (89%) were already receiving cotrimoxazole prophylaxis and 64 children (40%) had initiated antiretroviral therapy (ART). The median length of stay was 13 days (IQR: 7–23); 25 children (16%) died during hospitalization and four (3%) were transferred out. The leading causes of hospitalization were WHO stage 3 opportunistic infections (37%), non‐AIDS‐defining events (28%), cachexia and other WHO stage 4 events (25%).ConclusionsOverall, most causes of hospitalizations were HIV related but one hospitalization in three was caused by a non‐AIDS‐defining event, mostly in children on ART. HIV‐related fatality is also high despite the scaling‐up of access to ART in resource‐limited settings.
Signal Interference Technique for Wideband Filter Design
Authors: Mondal Priyanka , Mandal Mrinal Kanti 
Published: April 2014

Abstract
The signal interference technique is an efficient method for the design of wideband bandpass as well as bandstop filters with sharp rejection characteristics. The signal is filtered by dividing it into two components propagating through two transmission line segments with different electrical lengths and characteristic impedances. Bandpass or bandstop response is obtained by tuning the electrical lengths and/or impedances. Coupled lines also have been used in one or both of the signal paths. As a result, different configurations of the filter are possible and each of them shows interesting features.
Assessment of the capabilities of the temporal and spatiotemporal ICA method for geophysical signal separation in GRACE data
Authors: Boergens Eva , Rangelova Elena , Sideris Michael G. , Kusche Juergen 
Published: April 2014

AbstractWe investigate the potential of two independent component analysis (ICA) methods, i.e., the temporal and spatiotemporal ICA, for separating geophysical signals in Gravity Recovery and Climate Experiment (GRACE) data. These methods are based on the assumption of the statistical independence of the signals and thus separate the GRACE‐observed mass changes into maximal independent signals. These two ICA methods are compared to the conventional principal component analysis (PCA) method. We test the three methods with respect to their ability to separate a periodic hydrological signal from a trend signal originating in the solid Earth or the cryosphere with simulated and Center for Space Research GRACE mass changes for the time period of January 2003 to December 2010. In addition, we investigate whether the methods are capable of separating hydrological annual and semiannual mass variations. It is shown that both ICA methods are superior to PCA when non‐Gaussian mass variations are analyzed. Furthermore, the spatiotemporal ICA resolves successfully the lack of full temporal and spatial independence of the geophysical signals observed by GRACE both in global and regional simulation scenarios. Although the temporal and spatiotemporal ICA are nearly equivalent, both superior to PCA in the global GRACE analysis, the spatiotemporal ICA proves to be more efficient in regional applications by recover more reliably the postglacial rebound trend in North America and the bimodal total water storage variability in Africa.
Quantifying aerosol direct effects from broadband irradiance and spectral aerosol optical depth observations
Authors: Creekmore Torreon N. , Joseph Everette , Long Charles N. , Li Siwei 
Published: April 2014

AbstractWe outline a methodology using broadband and spectral irradiances to quantify aerosol direct effects on the surface diffuse shortwave (SW) irradiance. Best Estimate Flux data span a 13 year timeframe at the Department of Energy Atmospheric Radiation Measurement Program's Southern Great Plains (SGP) site. Screened clear‐sky irradiances and aerosol optical depth (AOD), for solar zenith angles ≤ 65°, are used to estimate clear‐sky diffuse irradiances. We validate against detected clear‐sky observations from SGP's Basic Radiation System (BRS). BRS diffuse irradiances were in accordance with estimates, producing a root‐mean‐square error and mean bias errors of 4.0 W/m2 and −1.4 W/m2, respectively. Absolute differences show 99% of estimates within ±10 W/m2 (10%) of the mean BRS observations. Clear‐sky diffuse estimates are used to derive quantitative estimates of aerosol radiative effects, represented as the aerosol diffuse irradiance (ADI). ADI is the contribution of diffuse SW to global SW, attributable to scattering of atmospheric transmission by natural plus anthropogenic aerosols. Estimated slope for the ADI as a function of AOD indicates an increase of ~22 W/m2 in diffuse SW for every 0.1 increase in AOD. Such significant increases in the diffuse fraction could possibly increase photosynthesis. Annual mean ADI is 28.2 W/m2, and heavy aerosol loading at SGP provides up to a maximum increase of 120 W/m2 in diffuse SW over background conditions. With regard to seasonal variation, the mean diffuse forcings are 17.2, 33.3, 39.0, and 23.6 W/m2 for winter, spring, summer, and fall, respectively.
Modulation of monsoon intraseasonal oscillations in the recent warming period
Authors: Sabeerali C. T. , Rao Suryachandra A , George Gibies , Rao D. Nagarjuna , Mahapatra S. , Kulkarni A. , Murtugudde Raghu 
Published: April 2014

AbstractThe Indian Ocean sea surface temperature (SST) during the boreal summer has shown a significant warming of 0.3°C in the recent decade (2001–2010) compared to a former decade (1979–1988), and it is most pronounced in the central tropical Indian Ocean. By using reanalysis and satellite‐derived data sets, we investigated how the monsoon intraseasonal oscillation (MISO) over the South Asian summer monsoon (ASM) region has been influenced by the recent warming in the Indian Ocean. It is found that the MISO variance has increased over the ASM region in the recent period compared with the earlier decade. It is also noted that the characteristic northward propagation of the MISO has slowed over 2001–2010, resembling more of a standing oscillation near the equator. Mechanisms implicated in the observed MISO changes are explored by conducting several model sensitivity experiments with an atmospheric general circulation model. The model experiments suggest that the mean SST increase over the Indian Ocean, and the associated changes in the air‐sea interaction, the increased mean moisture convergence, and changes in the large‐scale circulation are responsible for the changes in the characteristics of the MISO. The influence of the recent Indian Ocean warming on the MISO characteristics must be understood fully since they determine the seasonal amount of rainfall over the Indian subcontinent. An examination of future projections of the MISO using the MPI‐ESM‐LR model from the Coupled Model Intercomparison Project phase 5 archive also gives consistent result.
A transient deep‐sea circulation switch during Eocene Thermal Maximum 2
Authors: D'haenens Simon , Bornemann André , Claeys Philippe , Röhl Ursula , Steurbaut Etienne , Speijer Robert P. 
Published: April 2014

AbstractEver since its discovery, Eocene Thermal Maximum 2 (ETM2; ~53.7 Ma) has been considered as one of the “little brothers” of the Paleocene‐Eocene Thermal Maximum (PETM; ~56 Ma) as it displays similar characteristics including abrupt warming, ocean acidification, and biotic shifts. One of the remaining key questions is what effect these lesser climate perturbations had on ocean circulation and ventilation and, ultimately, biotic disruptions. Here we characterize ETM2 sections of the NE Atlantic (Deep Sea Drilling Project Sites 401 and 550) using multispecies benthic foraminiferal stable isotopes, grain size analysis, XRF core scanning, and carbonate content. The magnitude of the carbon isotope excursion (0.85–1.10‰) and bottom water warming (2–2.5°C) during ETM2 seems slightly smaller than in South Atlantic records. The comparison of the lateral δ13C gradient between the North and South Atlantic reveals that a transient circulation switch took place during ETM2, a similar pattern as observed for the PETM. New grain size and published faunal data support this hypothesis by indicating a reduction in deepwater current velocity. Following ETM2, we record a distinct intensification of bottom water currents influencing Atlantic carbonate accumulation and biotic communities, while a dramatic and persistent clay reduction hints at a weakening of the regional hydrological cycle. Our findings highlight the similarities and differences between the PETM and ETM2. Moreover, the heterogeneity of hyperthermal expression emphasizes the need to specifically characterize each hyperthermal event and its background conditions to minimalize artifacts in global climate and carbonate burial models for the early Paleogene.
Inference of permeability heterogeneity from joint inversion of transient flow and temperature data
Authors: Zhang Zhishuai , Jafarpour Behnam , Li Lianlin 
Published: April 2014

AbstractCharacterization of the rock permeability distribution in compartmentalized deep aquifers, enhanced geothermal systems, and hydrocarbon reservoirs is important for predicting the flow and transport behavior in these formations. Reliable prediction of the fluid flow and transport processes can, in turn, lead to effective development of the subsurface energy and environmental resources. In deep formations where thermal gradients are significant, the transient temperature data can provide valuable information about the permeability distribution with depth and about the vertical fluid displacement. This paper examines the importance of temperature data in resolving the distribution of permeability with depth by jointly, and individually, integrating the transient temperature and flow data. We demonstrate that when estimating permeability distributions in deep geothermal reservoirs, incorporating temperature data can increase the resolution of the permeability distribution profile with depth. To illustrate the importance of temperature measurements, we adopt a coupled transient heat and fluid flow as a forward model to predict the heat and fluid transport in a geothermal reservoir and develop an adjoint model for efficient computation of the gradient information for model calibration. We perform a series of numerical experiments for integration of flow and pressure data alone, temperature data alone, and flow and pressure jointly with temperature data. In each case, we apply the maximum A‐posteriori (MAP) method and the randomized maximum likelihood (RML) method for inversion and uncertainty quantification. Analysis of the sensitivity of temperature and production data to heterogeneous permeability distributions reveals that the temperature of fluid, even when measured at the surface, is sensitive to the permeability distribution in the vertical extent of the reservoir. Hence, temperature measurements can be augmented with flow‐related data to enhance the resolution of the estimated permeability field with depth.
Data‐driven numerical simulations of equatorial spread F in the Peruvian sector
Authors: Hysell D. L. , Jafari R. , Milla M. A. , Meriwether J. W. 
Published: April 2014

AbstractIonospheric state parameters including plasma number density and vector drift velocity profiles were measured at the Jicamarca Radio Observatory during a campaign running from 12 to 18 April 2013. Neutral winds were measured by the red‐line Fabry Perot interferometer at Jicamarca. Coherent radar backscatter from plasma irregularities associated with equatorial spread F (ESF) was also recorded. A numerical simulation of ionospheric irregularities, initialized and forced using parameterizations derived from a combination of measurements and empirical models, was used to try to reproduce the ESF activity that occurred on three different nights. Simulations were able to recover the salient features of the irregularities that formed in each case and produce bottom‐type, bottomside, and topside ESF. Realistic simulations require the accurate representation of the vertical currents that generate irregularities initially at the base of the F region as well as the zonal currents necessary for irregularities to expand in altitude and penetrate to the topside. The campaign data, numerical simulations, and protocols used to associate them are presented and evaluated.
Some aspects of the problem of secondary eyewall formation in idealized three‐dimensional nonlinear simulations
Authors: Menelaou K. , Yau M. K. , Martinez Y. 
Published: April 2014

AbstractSome aspects of the problem of secondary eyewall formation (SEF) are investigated with the aid of an idealized model. A series of experiments are conducted, starting with a strong annular vortex embedded in a quiescent background flow and forced by the sustained heating associated with a spiral rainband (control experiment). Following this, two experiments are configured to assess the impact of vertical wind shear (VWS) in the SEF process. The importance of the boundary layer force imbalance is finally investigated in a number of simulations in which surface and boundary layer physics are included. From the control experiment, it is found that in the absence of background environmental flow, the sustained latent heating associated with a spiral rainband can form a secondary eyewall even in the absence of a frictional boundary layer. The presence of VWS acts negatively in the SEF process by disrupting the organization of the potential vorticity induced by the rainband. When boundary layer physics is included, some similarities with previous studies are seen, but there is no SEF. These results suggest that the boundary layer most likely contributes to, rather than initiate, a secondary eyewall.
Rapid and sustained surface ocean acidification during the Paleocene‐Eocene Thermal Maximum
Authors: Penman Donald E. , Hönisch Bärbel , Zeebe Richard E. , Thomas Ellen , Zachos James C. 
Published: April 2014

AbstractThe Paleocene‐Eocene Thermal Maximum (PETM) has been associated with the release of several thousands of petagrams of carbon (Pg C) as methane and/or carbon dioxide into the ocean‐atmosphere system within ~10 kyr, on the basis of the co‐occurrence of a carbon isotope excursion (CIE), widespread dissolution of deep sea carbonates, and global warming. In theory, this rapid carbon release should have severely acidified the surface ocean, though no geochemical evidence has yet been presented. Using boron‐based proxies for surface ocean carbonate chemistry, we present the first observational evidence for a drop in the pH of surface and thermocline seawater during the PETM. Planktic foraminifers from a drill site in the North Pacific (Ocean Drilling Program Site 1209) show a ~0.8‰ decrease in boron isotopic composition (δ11B) at the onset of the event, along with a 30–40% reduction in shell B/Ca. Similar trends in δ11B are present in two lower‐resolution records from the South Atlantic and Equatorial Pacific. These observations are consistent with significant, global acidification of the surface ocean lasting at least 70 kyr and requiring sustained carbon release. The anomalies in the B records are consistent with an initial surface pH drop of ~0.3 units, at the upper range of model‐based estimates of acidification.
Carbon‐Fiber‐Reinforced Silicon Carbide: a New Brake Disk Material
Authors: Kienzle Andreas , Jäger Hubert 
Published: April 2014

Abstract

Since 1950, the top speed of luxury class limousines increased from around 180 to 250 km/h in the year 2010. In the same time, also the car weight increased from around 1400 to 2500 kg. This leads to higher kinetic energy, which results in a lower lifetime of the metal disks and fading problems, with the result of longer stopping distances. In the past decade, the carbon‐fiber‐reinforced silicon carbide brake disk material is developed. The material is produced by liquid siliconization of porous carbon‐fiber‐reinforced carbon preform with liquid silicon under vacuum. The resulting material shows a low weight because of the low densities of around 2.3 gcm
−3
and high hardness. At the Frankfurt Motor Show in 1999, the carbon‐ceramic brake disk was shown the first time to the public. At present, for nearly all high end sport and luxury cars,
CF
/
SiC
brake disks are available. In this contribution, the production processes of the
CF
/
SiC
disks are described and an overview of the
CF
/
SiC
material and brake disk behavior is given.
Choosing Wisely: The American College of Rheumatology's Top 5 for Pediatric Rheumatology
Authors: Rouster‐Stevens Kelly A. , Ardoin Stacy P. , Cooper Ashley M. , Becker Mara L. , Dragone Leonard L. , Huttenlocher Anna , Jones Karla B. , Kolba Karen S. , Moorthy L. Nandini , Nigrovic Peter A. , Stinson Jennifer N. , Ferguson Polly J. ,   for the American College of Rheumatology Pediatric Rheumatology Core Membership Group
Published: April 2014

ObjectiveTo create a pediatric rheumatology Top 5 list as part of the American Board of Internal Medicine Foundation's Choosing Wisely campaign.MethodsDelphi surveys of a core group of representative pediatric rheumatology providers from across North America generated candidate Top 5 items. Items with high content agreement and perceived to be of prevalent use and of high impact were included in a survey of all American College of Rheumatology (ACR) members who identified themselves as providing care to pediatric patients. Items with the highest ratings were subjected to literature review and further evaluation.ResultsA total of 121 candidate items were proposed in the initial Delphi survey and were reduced to 28 items in subsequent surveys. These 28 items were sent to 1,198 rheumatology providers who care for pediatric patients, and 397 (33%) responded. Based upon survey data and literature review, the Top 5 items were identified. These items focused on testing for antinuclear antibodies, autoantibody panels, Lyme disease, methotrexate toxicity monitoring, and use of routine radiographs.ConclusionThe ACR pediatric rheumatology Top 5 is one of the first pediatric subspecialty–specific Choosing Wisely Top 5 lists and provides an opportunity for patients and providers to discuss appropriate use of health care in pediatric rheumatology.
Development and Validation of the Lupus Impact Tracker: A Patient‐Completed Tool for Clinical Practice to Assess and Monitor the Impact of Systemic Lupus Erythematosus
Authors: Jolly Meenakshi , Garris Cindy P. , Mikolaitis Rachel A. , Jhingran Priti M. , Dennis Greg , Wallace Daniel J. , Clarke Ann , Dooley Mary Anne , Parke Ann , Strand Vibeke , Alárcon Graciela S. , Kosinski Mark 
Published: April 2014

ObjectiveTo derive and validate a brief patient‐completed instrument, the Lupus Impact Tracker (LIT), to assess and monitor the impact of systemic lupus erythematosus (SLE).MethodsItems for the LIT were selected from the LupusPRO, a validated patient‐reported outcomes measure, using 3 approaches: confirmatory factor analysis (CFA), stepwise regression, and patient focus groups. CFA was conducted to find items from the LupusPRO that fit a unidimensional structure to allow scoring as a single index. Stepwise regression methods identified items with the strongest relationship (convergent validity) with disease activity measures and patient health rating. Focus groups (n = 26 patients) identified the most important items describing SLE impact. Selected items were evaluated for reliability and validity.ResultsCFA found 21 items that fit a unidimensional structure. Stepwise regressions identified 15 of 21 items having good convergent validity with clinical measures. Patient focus groups identified 9 of 15 items as best capturing the impact of SLE. Overall, 7 items were selected across all 3 approaches (CFA, stepwise regression, and focus groups). Another 15 items were selected across 2 approaches. Through consensus with rheumatology clinician experts, a final set of 10 items was selected for the LIT. The LIT items showed good internal consistency (0.89) and test–retest reliabilities (0.87). Mean LIT scores differed significantly (P < 0.05) across criterion groups in the hypothesized direction, providing evidence of discriminant validity and responsiveness.ConclusionThe LIT is reliable and valid in SLE patients and offers a practical way for physicians and patients to assess and monitor the impact of SLE.
Parental Influence on Systemic Sclerosis
Authors: Frech Tracy M. , Pimentel Richard , Mineau Geraldine , Sawitzke Allen , Penmetsa Gopi , Wong Jathine 
Published: April 2014

ObjectiveTo examine parental influence on the development of systemic sclerosis (SSc; scleroderma). We designed 3 studies: mitochondrial inheritance, birth order (a possible surrogate marker for microchimerism), and paternal age at conception (a possible surrogate for telomere erosion) to examine their association with development of SSc.MethodsSSc was defined by International Classification of Diseases, Ninth and Tenth Revision codes (ICD‐9 710.1 and ICD 10 M34.0, M34.1, and M34.9) and identified from statewide discharge data, University of Utah Health Science Center Enterprise Data Warehouse (UUHSC), and death certificates that were linked to the Utah Population Database (UPDB) for analysis. Mitochondrial inheritance was evaluated by conditional logistic regression and population attributable risk using familial standardized incidence ratio as the covariate. Chi‐square test and logistic regression were used to evaluate birth order and maternal/paternal age at conception of the SSc proband.ResultsWe found 1,947 unique SSc patients from UUHSC and UPDB. We selected 5 controls per case (n = 9,115), matched by birth year and sex. Mitochondrial inheritance analysis indicated no evidence to suggest SSc was associated with mitochondrial inheritance. Birth order and maternal/paternal age at conception analysis results show that they also do not significantly affect SSc development.ConclusionResults suggest that although heritable risk of SSc is observed, mitochondrial inheritance, birth order, and parental age are not likely responsible for pathogenesis.
Organocatalytic Asymmetric Condensation/Keto–Enol Tautomerization Tandem Reaction: Access to Cyclobutanone α‐Amino Acid Ester Derivatives
Authors: Frongia Angelo , Melis Nicola , Serra Ilaria , Secci Francesco , Piras Pier Paolo , Caboni Pierluigi 
Published: April 2014

AbstractA practical method for the synthesis of optically active α‐amino cyclobutanones has been developed, via an organocatalytic asymmetric condensation reaction between racemic 2‐hydroxycyclobutanone and chiral N‐alkyl‐α‐amino acid ester derivatives.