bluuebunny/crossref_metadata_2025_split huggingface dataset:
Direction-dependent Corrections in Polarimetric Radio Imaging. I. Characterizing the Effects of the Primary Beam on Full-Stokes Imaging
Authors: Jagannathan P. , Bhatnagar S. , Rau U. , Taylor A. R. 
Published: July 2017

Abstract
Next generation radio telescope arrays are being designed and commissioned to accurately measure polarized intensity and rotation measures (RMs) across the entire sky through deep, wide-field radio interferometric surveys. Radio interferometer dish antenna arrays are affected by direction-dependent (DD) gains due to both instrumental and atmospheric effects. In this paper, we demonstrate the effect of DD errors of the parabolic dish antenna array on the measured polarized intensities of radio sources in interferometric images. We characterize the extent of polarimetric image degradation due to the DD gains through wide-band VLA simulations of representative point-source simulations of the radio sky at L band (1–2 GHz). We show that at the 0.5 gain level of the primary beam there is significant flux leakage from Stokes I to Q, U amounting to 10% of the total intensity. We further demonstrate that while the instrumental response averages down for observations over large parallactic angle intervals, full-polarization DD correction is required to remove the effects of DD leakage. We also explore the effect of the DD beam on the RM signals and show that while the instrumental effect is primarily centered around 0 rad-m−2, the effect is significant over a broad range of RM requiring full polarization DD correction to accurately reconstruct the RM synthesis signal.
An Investigation of the Formation and Line Properties of MgH in 3D Hydrodynamical Model Stellar Atmospheres
Authors: Thygesen Anders O. , Kirby Evan N. , Gallagher Andrew J. , Ludwig Hans-G. , Caffau Elisabetta , Bonifacio Piercarlo , Sbordone Luca 
Published: July 2017

Abstract
Studies of the isotopic composition of magnesium in cool stars have so far relied upon the use of 1D model atmospheres. Since the isotopic ratios derived are based on asymmetries of optical MgH lines, it is important to test the impact from other effects affecting line asymmetries, like stellar convection. Here, we present a theoretical investigation of the effects of including self-consistent modeling of convection. Using spectral syntheses based on 3D hydrodynamical CO5BOLD models of dwarfs (4000 K ≲ T
eff ≲ 5160 K, 4.0 ≤

≤ 4.5,

) and giants (T
eff ∼ 4000 K,

= 1.5,

), we perform a detailed analysis comparing 3D and 1D syntheses. We describe the impact on the formation and behavior of MgH lines from using 3D models, and perform a qualitative assessment of the systematics introduced by the use of 1D syntheses. Using 3D model atmospheres significantly affect the strength of the MgH lines, especially in dwarfs, with 1D syntheses requiring an abundance correction of up to +0.69 dex, with the largest for our 5000 K models. The corrections are correlated with T
eff and are also affected by the metallicity. The shape of the strong 24MgH component in the 3D syntheses is poorly reproduced in 1D. This results in 1D syntheses underestimating 25Mg by up to ∼5 percentage points and overestimating 24Mg by a similar amount for dwarfs. This discrepancy increases with decreasing metallicity. 26Mg is recovered relatively well, with the largest difference being ∼2 percentage points. The use of 3D for giants has less impact, due to smaller differences in the atmospheric structure and a better reproduction of the line shape in 1D.
Polarimetry and Photometry of Gamma-Ray Bursts with RINGO2
Authors: Steele I. A. , Kopač D. , Arnold D. M. , Smith R. J. , Kobayashi S. , Jermak H. E. , Mundell C. G. , Gomboc A. , Guidorzi C. , Melandri A. , Japelj J. 
Published: July 2017

Abstract
We present a catalog of early-time (

s) photometry and polarimetry of all gamma-ray burst (GRB) optical afterglows observed with the RINGO2 imaging polarimeter on the Liverpool Telescope. Of the 19 optical afterglows observed, the following nine were bright enough to perform photometry and attempt polarimetry: GRB 100805A, GRB 101112A, GRB 110205A, GRB 110726A, GRB 120119A, GRB 120308A, GRB 120311A, GRB 120326A, and GRB 120327A. We present multiwavelength light curves for these 9 GRBs, together with estimates of their optical polarization degrees and/or limits. We carry out a thorough investigation of detection probabilities, instrumental properties, and systematics. Using two independent methods, we confirm previous reports of significant polarization in GRB 110205A and 120308A, and report the new detection of

% in GRB101112A. We discuss the results for the sample in the context of the reverse- and forward-shock afterglow scenario, and show that GRBs with detectable optical polarization at early time have clearly identifiable signatures of reverse-shock emission in their optical light curves. This supports the idea that GRB ejecta contain large-scale magnetic fields, and it highlights the importance of rapid-response polarimetry.
À la recherche de la race arabe : cheval et voyage en Arabie centrale au XIXe siècle
Authors: Pouillon François 
Published: July 2017

L’Arabie centrale est restée très tardivement à l’écart des entreprises d’exploration qui, au XIXe siècle, s’attachent méthodiquement à sillonner la planète. Ceux qui l’entreprirent finalement, Carlo Guarmani et les Blunt notamment, étaient particulièrement attachés à rechercher des chevaux de pure race arabe, et ceux‑ci constituent donc un vecteur important de ces explorations. Le caractère un peu paradoxal de cette quête — car le cheval ne survit pas facilement dans un environnement d’aridité extrême — dénote en outre une évolution des mentalités concernant la représentation du désert qui, en ces temps postromantiques, n’est plus perçu comme une marge hostile et répulsive mais comme une entité géographique positive : un foyer d’où sortent des races — le concept prend alors tout son autorité — nobles aux vertus particulières.
Oxidative Stress: A Potential Therapeutic Target in Placental Malaria
Authors: Sarr Demba , Cooper Caitlin A , Bracken Tara C , Martinez-Uribe Omar , Nagy Tamas , Moore Julie M 
Published: July 2017

Abstract
Placental malaria, characterized by sequestration of Plasmodium falciparum in the maternal placental blood space and associated inflammatory damage, contributes to poor birth outcomes and ∼200,000 infant deaths annually. Specific mechanisms that contribute to placental damage and dysfunction during malaria are not completely understood. To investigate a potential role for oxidative stress, antioxidant genes and markers for oxidative damage were assessed by quantitative PCR and immunohistochemistry in Plasmodium chabaudi AS-infected pregnant mice. Widespread evidence of lipid peroxidation was observed and was associated with higher antioxidant gene expression in conceptuses of infected mice. To assess the extent to which this oxidative damage might contribute to poor birth outcomes and be amenable to therapeutic intervention, infected pregnant mice were treated with N-acetylcysteine, a free radical scavenger, or tempol, an intracellular superoxide dismutase mimetic. The results show that mice treated with N-acetylcysteine experienced malaria induced–pregnancy loss at the same rate as control animals and failed to mitigate placental oxidative damage. In contrast, tempol-treated mice exhibited subtle improvement in embryo survival at gestation day 12. Although lipid peroxidation was not consistently reduced in the placentas of these mice, it was inversely related to embryo viability. Moreover, reduced IFN-γ and CCL2 plasma levels in treated mice were associated with midgestational embryo viability. Thus, although oxidative stress is remarkable in placental malaria and its mitigation by antioxidant therapy may improve pregnancy outcomes, the underlying mechanistic basis and potential therapeutic strategies require additional investigation.
Health systems: A review of the concept, global challenges and reforms
Authors: El-Fallah Mohamed 
Published: July 2017

The study of health systems (HSs) is an important but confusing field. Its unclear boundaries, overlap, and multiple interpretations of terms require conceptual clarification. In light of the available evidence, Firstly, it is very important to realize that the current HSs thinking addresses individual parts rather than the whole HS. Secondly, it fails to recognize that concentrating on the performance of one part of the HS may have damaging effects on the whole HS. Thirdly, current HSs thinking fails to address the views, interests and influence of human resources for health involved in the implementation of reform, and how people and communities are expected to benefit from it. Fourthly, it does not take into account the different meanings, perceptions, cultural values and beliefs that may influence the very different institutions and structures belonging to a HS and working towards the same goals. Fifthly, the structural parts of HSs are designed to work in a stable environment, rather than addressing the ever changing context. Finally, HSs thinking does not provide a structural response to cope with the variety of healthcare stakeholders. The way HSs are currently understood may contribute to their weak performance. The current understanding is fundamentally functionalist, because the practice has focused on the definition of the structure, units and functions at different levels of recursion. The analysis of the literature demonstrates that most existing HSs are underpinned by functionalist approaches.This review provides a conceptual framework for many of the studies that focuses on specific situations and localities and explores what other approaches and methodologies can offer, in order to develop a framework for a given HS, which is more relevant in theory and practice than the other functionalist frameworks that may have been adopted previously. This framework will hopefully also narrow the gap between HSs goals and performance.
Water-mass evolution in the Cretaceous Western Interior Seaway of North America and equatorial Atlantic
Authors: Eldrett James S. , Dodsworth Paul , Bergman Steven C. , Wright Milly , Minisini Daniel 
Published: July 2017

Abstract. The Late Cretaceous Epoch was characterized by major global perturbations in the carbon cycle, the most prominent occurring near the Cenomanian–Turonian (CT) transition marked by Oceanic Anoxic Event 2 (OAE-2) at 94.9–93.7 Ma. The Cretaceous Western Interior Seaway (KWIS) was one of several epicontinental seas in which a complex water-mass evolution was recorded in widespread sedimentary successions. This contribution integrates new data on the main components of organic matter, geochemistry, and stable isotopes along a north–south transect from the KWIS to the equatorial western Atlantic and Southern Ocean. In particular, cored sedimentary rocks from the Eagle Ford Group of west Texas (∼ 90–98 Ma) demonstrate subtle temporal and spatial variations in palaeoenvironmental conditions and provide an important geographic constraint for interpreting water-mass evolution. High-latitude (boreal–austral), equatorial Atlantic Tethyan and locally sourced Western Interior Seaway water masses are distinguished by distinct palynological assemblages and geochemical signatures. The northward migration of an equatorial Atlantic Tethyan water mass into the KWIS occurred during the early–middle Cenomanian (98–95 Ma) followed by a major re-organization during the latest Cenomanian–Turonian (95–94 Ma) as a full connection with a northerly boreal water mass was established during peak transgression. This oceanographic change promoted de-stratification of the water column and improved oxygenation throughout the KWIS and as far south as the Demerara Rise off Suriname. In addition, the recorded decline in redox-sensitive trace metals during the onset of OAE-2 likely reflects a genuine oxygenation event related to open water-mass exchange and may have been complicated by variable contribution of organic matter from different sources (e.g. refractory/terrigenous material), requiring further investigation.
Delineating wetland catchments and modeling hydrologic connectivity using lidar data and aerial imagery
Authors: Wu Qiusheng , Lane Charles R. 
Published: July 2017

Abstract. In traditional watershed delineation and topographic modeling, surface depressions are generally treated as spurious features and simply removed from a digital elevation model (DEM) to enforce flow continuity of water across the topographic surface to the watershed outlets. In reality, however, many depressions in the DEM are actual wetland landscape features with seasonal to permanent inundation patterning characterized by nested hierarchical structures and dynamic filling–spilling–merging surface-water hydrological processes. Differentiating and appropriately processing such ecohydrologically meaningful features remains a major technical terrain-processing challenge, particularly as high-resolution spatial data are increasingly used to support modeling and geographic analysis needs. The objectives of this study were to delineate hierarchical wetland catchments and model their hydrologic connectivity using high-resolution lidar data and aerial imagery. The graph-theory-based contour tree method was used to delineate the hierarchical wetland catchments and characterize their geometric and topological properties. Potential hydrologic connectivity between wetlands and streams were simulated using the least-cost-path algorithm. The resulting flow network delineated potential flow paths connecting wetland depressions to each other or to the river network on scales finer than those available through the National Hydrography Dataset. The results demonstrated that our proposed framework is promising for improving overland flow simulation and hydrologic connectivity analysis.
FUNCTIONALIZATION OF ACRYLONITRILE BUTADIENE RUBBER WITH META-PENTADECENYL PHENOL, A MULTIFUNCTIONAL ADDITIVE AND A RENEWABLE RESOURCE
Authors: Samantarai Satyajit , Mahata Denial , Nag Ahindra , Nando Golok B. , Das Narayan C. 
Published: July 2017

ABSTRACT
The present invention deals with the functionalization of acrylonitrile butadiene rubber (NBR) by chemically grafting meta-pentadecenyl phenol (cardanol) onto the backbone chain. This imparts inherent multifunctional characteristics to the nitrile rubber. The grafting of cardanol onto NBR was accomplished successfully in emulsion stage using benzoyl peroxide (BPO) as a free radical initiator. The grafted NBR is characterized by ultraviolet–visible, Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy, and gel permeation chromatography. Cardanol grafted NBR (CGNBR) shows an increase in molecular weight (6.6%) with an increase in polydispersity index value. The optimal conditions of grafting are found out to be, “1 phr BPO, 15 phr cardanol, at a reaction temperature of 60 °C and a reaction time 10 h” by using the “Taguchi L9 orthogonal array” method. The grafting efficiency and percentage grafting are calculated to be 79.2% and 7.1%, respectively, at the optimum combination of parameters. The CGNBR shows an increase in molecular weight and reduction in Wallace plasticity number as well as Mooney viscosity, but exhibits a higher plasticity retention index value, as compared to ungrafted NBR. The rheological characteristics of CGNBR exhibit a better flow behavior index than NBR. Differential scanning calorimetry, dynamic mechanical analysis results exhibit a decrease in Tg value for grafted NBR. Thermogravimetric analysis results displayed an increase in thermal stability of the functionalized NBR than that of raw NBR.
Hypomagnesemia and Cause-specific Mortality in Hemodialysis Patients: 5-year follow-up Analysis
Authors: Selim Gjulsen N. , Spasovski Goce , Tozija Liljana , Georgievska-Ismail Ljubica , Zafirova-Ivanovska Beti , Masin-Spasovska Jelka , Rambabova-Busletic Irena , Petronijevic Zvezdana , Dzekova-Vidimliski Pavlina , Ristovska Vesna , Pusevski Vladimir , Stojceva-Taneva Olivera 
Published: July 2017

Introduction The aim of this prospective study was to evaluate the association between serum magnesium (Mg) and mortality, in particular the cause-specific mortality of Mg and other risk factors in hemodialysis (HD) patients. Methods We studied a cohort of 185 HD patients receiving thrice-weekly HD treatment, on a dialysate Mg concentration of 0.5 mmol/L. We stratified 3 patient groups according to the level of Mg: lower (<1.1 mmol/L), intermediate-reference (1.1 to <1.3 mmol/L), and higher (Mg >1.3 mm/L). Results During the 5-year follow-up, 60 patients died, with cardiovascular (CV) disease as the predominant cause (73.3%). Hazard ratio (HR) for all-cause and CV mortality were 2.55 and 2.67 in the lower versus intermediate Mg group, but there was no significant association between the higher and intermediate Mg group. Univariate Cox regression analysis showed that Mg <1.1 versus 1.1–1.30 mml/L with HR 2.34, was a significant univariate predictor for increased mortality in addition to the Hb <110 g/L, Alb <40 g/L, C-reactive protein (CRP) ≥10 mg/L and brain natriuretic peptide >1,200 pg/mL However, in the multivariate analysis only CRP ≥10 mg/L with HR 3.89 was a significant predictor of mortality. Subgroup analyses showed that among patients with CRP >10 mg/L, HR for all-cause and CV mortality of the lower versus intermediate Mg group were 1.96 and 2.39, respectively, not reaching significance for the higher versus intermediate Mg group. Conversely, there was no association between Mg level and all-cause and CV mortality within these 3 groups among patients with CRP <10 mg/L. Conclusions Lower serum Mg level was significantly associated with an increased all-cause and cardiovascular mortality in HD patients, especially in inflamed patients.
Particle Image Velocimetry Tests on Pediatric 45-cc and 30-cc Ventricle Assist Devices: Effects of Heart Rate on VAD Operation
Authors: Witkowski Dariusz , Obidowski Damian , Reorowicz Piotr , Jodko Daniel , Jozwik Krzysztof 
Published: July 2017

Background This study investigated flow analysis inside pediatric ventricle assist devices (VADs) designed and manufactured at the Foundation for Cardiac Surgery Development (FRK), Zabrze, Poland. The main goal of the experiment was to define the minimal heart rate admissible in clinical practice. Methods The flow was directed by mechanical, single-disc valves developed at the Lodz University of Technology, Institute of Turbomachinery in Lodz, Poland. VAD operation conditions under different heart rates were analyzed. Measurements were performed on Religa PED pediatric VADs (45 cm3 and 30 cm3) with a particle image velocimetry (PIV) system. Results Due to the PIV method used, the measurements were made without interference of the measuring system onto the flow structure in the investigated channel, as the measurement procedure is noninvasive. During the investigations conducted in different measurement planes, the majority of the flow volume in the chamber was observable. Conclusions The measurements at different heart rates demonstrated a significant influence of this parameter on the flow nature in the heart ventricle. Additionally, it was found that the heart rate affected the operation of heart valves in the VAD.
Evaluation of Calcium (Ca2+) and Hydroxide (OH–) Ion Diffusion Rates of Indirect Pulp Capping Materials
Authors: Aksoy Merve Kurun , Oz Firdevs Tulga , Orhan Kaan 
Published: July 2017

Introduction The aim of this study was to evaluate and compare the calcium (Ca2+) and hydroxide (OH–) ion release of 4 artificially produced pulp capping materials (MTA, Biodentin, TheraCal LC, Calsimol) used for indirect pulp capping treatment. Methods In total, 70 freshly extracted human third molar teeth were used for the study. Cavities of extracted teeth were prepared by round burs. The remaining dentin thickness (1 ± 0.3 mm) tissue was measured by a micrometer and cone beam computerized tomography. Indirect pulp capping was performed in the cavities using Calcimol, MTA, TheraCal LC and Biodentin. The leached Ca2+ were measured using optical emission spectrometry and the release of OH– ions using a pH meter. The measurements were performed after 24 hours, 7 days and 28 days in saline solution. Statistical analysis was performed using 1-way and 2-way analysis of variance (ANOVA) tests (p<0.05). Results Ca2+ ions were detected in treated saline solution during the experimental period for all materials. All the measurements of Biodentin and Theracal LC levels for Ca2+ ions were higher than those of the other materials (p<0.05). For all materials, Ca2+-ion release increased during the first 7 days followed by a linear decrease during the subsequent study periods. The Biodentine group showed the highest OH– ion rates compared to the other materials in the 24-hour examination period, while the scores gradually decreased during the subsequent measurement periods (p<0.05). Conclusions Tricalcium silicate materials such as Biodentine and TheraCal LC used in this study may be preferable for indirect pulp capping because of their stimulation of hard tissue formation and ion-releasing ability.
Differential expression of hepatocyte growth factor in patients with systemic sclerosis-associated pulmonary arterial hypertension
Authors: Sung Yon K. , Zamanian Roham T. , Wagner Catriona A. , Robinson William , Steen Virginia , Chung Lorinda 
Published: July 2017

Introduction Non-invasive biomarkers are needed to identify pulmonary arterial hypertension (PAH) in systemic sclerosis (SSc) patients who may benefit from early intervention. We sought to identify novel cytokines that differentiate patients with incident SSc-PAH from those at high risk for PAH. Methods The Pulmonary Hypertension Assessment and Recognition of Outcomes in Scleroderma (PHAROS) Registry is a multicenter registry of SSc patients at high risk for PAH (at-risk) or with incident right-heart catheterization-confirmed PAH (definite PAH). Serum from 10 at-risk and 9 definite PAH patients were profiled with Bio-PlexTM bead arrays for 48 cytokines and chemokines. We also evaluated the longitudinal change in cytokine profiles from 3 at-risk patients who subsequently developed definite PAH. Results Clinical features of at-risk versus definite PAH patients were not significantly different except for right-ventricular systolic pressure on echocardiogram (34 ± 7 vs. 45 ± 8 mmHg, p = 0.006), left atrial diameter (2.9 ± 0.5 vs. 3.7 ± 0.4 cm, p = 0.02), 6-minute walk distance (508 ± 115 vs. 393 ± 70 m, p = 0.02), mean pulmonary artery pressure (18 ± 4 vs. 32 ± 6 mmHg, p = 0.01), and pulmonary vascular resistance (111 ± 48 vs. 272 ± 109 dyn/s/cm5, p = 0.009). Serum cytokine profiling identified hepatocyte growth factor (HGF) as the only cytokine significantly different between the at-risk and definite PAH groups (225.8 ± 55.0 vs. 361.6 ± 164.5 pg/mL, q<0.1%). Profiling of longitudinal samples of at-risk to definite PAH patients did not identify any significant changes in HGF or other cytokines over time. Conclusions Definite PAH patients expressed higher levels of HGF than at-risk patients. Further studies are needed to clarify the utility of HGF as a predictive biomarker for SSc-PAH.