bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mental health challenges among adolescents living with HIV
Authors: Vreeman Rachel C. , McCoy Brittany M. , Lee Sonia 
Published: May 2017

AbstractIntroduction: Mental health is a critical and neglected global health challenge for adolescents infected with HIV. The prevalence of mental and behavioural health issues among HIV‐infected adolescents may not be well understood or addressed as the world scales up HIV prevention and treatment for adolescents. The objective of this narrative review is to assess the current literature related to mental health challenges faced by adolescents living with HIV, including access to mental health services, the role of mental health challenges during transition from paediatric to adult care services and responsibilities, and the impact of mental health interventions.Methods: For each of the topics included in this review, individual searches were run using Medline and PubMed, accompanied by scans of bibliographies of relevant articles. The topics on which searches were conducted for HIV‐infected adolescents include depression and anxiety, transition from paediatric to adult HIV care and its impact on adherence and mental health, HIV‐related, mental health services and interventions, and the measurement of mental health problems. Articles were included if the focus was consistent with one of the identified topics, involved HIV‐infected adolescents, and was published in English.Results and Discussion: Mental and behavioural health challenges are prevalent in HIV‐infected adolescents, including in resource‐limited settings where most of them live, and they impact all aspects of HIV prevention and treatment. Too little has been done to measure the impact of mental health challenges for adolescents living with HIV, to evaluate interventions to best sustain or improve the mental health of this population, or to create healthcare systems with personnel or resources to promote mental health.Conclusions: Mental health issues should be addressed proactively during adolescence for all HIV‐infected youth. In addition, care systems need to pay greater attention to how mental health support is integrated into the care management for HIV, particularly throughout lifespan changes from childhood to adolescence to adulthood. The lack of research and support for mental health needs in resource‐limited settings presents an enormous burden for which cost‐effective solutions are urgently needed.
Transition from paediatric to adult care of adolescents living with HIV in sub‐Saharan Africa: challenges, youth‐friendly models, and outcomes
Authors: Dahourou Désiré Lucien , Gautier‐Lafaye Chloé , Teasdale Chloe A. , Renner Lorna , Yotebieng Marcel , Desmonde Sophie , Ayaya Samuel , Davies Mary‐Ann , Leroy Valériane 
Published: May 2017

AbstractIntroduction: The number of adolescents with perinatally or behaviourally acquired HIV is increasing in low‐income countries, and especially in sub‐Saharan Africa where HIV prevalence and incidence are the highest. As they survive into adulthood in the era of antiretroviral therapy, there is a pressing need to transfer them from paediatric to adult care, known as the transition of care. We conducted a narrative review of recent evidence on their transition outcomes in Africa, highlighting the specific needs and challenges in these populations and settings, and the different models of care for transition.Areas covered: We searched PubMed bibliographic database, HIV conference content, and grey literature from January 2000 to August 2016 with the following keywords: HIV infections AND (adolescents or youth) AND transition AND Africa. All qualitative and quantitative, experimental and observational studies including HIV‐infected patients aged 10–24 years with information on transition were eligible.Results: Few data on transition outcomes for HIV‐infected adolescents are available from Africa settings. Studies mainly from Southern and East Africa reported on the barriers to successful transition, highlighting several gaps. These included lack of adequate infrastructure, staff training and communication between paediatric and adult clinicians as well as the fear of stigma of adolescents and youth living with HIV. Most countries have no specific national guidelines on when to disclose HIV status or when and how to transition to adult care. Several models of care adapted to the adolescent transition question have been implemented in specific settings. These models include teen clinics, peer educators or the use of social media. However, regardless of the model, services are increasingly overburdened and have insufficient human resources. Furthermore, very high attrition has been observed among adolescents and youth compared to younger children or older adults. There is a need to identify sub‐groups at higher risk of loss to follow‐up for targeted care and peer support.Expert commentary: Although the available HIV‐related data on adolescent transition outcomes are limited, there is evidence of their increased vulnerability during this period. Standardized data gathering, analysis, and reporting systems specific to adolescent transition are essential to improve understanding and adolescent outcomes in Africa.
Plastomes of the green algae Hydrodictyon reticulatum and Pediastrum duplex (Sphaeropleales, Chlorophyceae)
Authors: McManus Hilary A. , Sanchez Daniel J. , Karol Kenneth G. 
Published: May 2017

Background
Comparative studies of chloroplast genomes (plastomes) across the Chlorophyceae are revealing dynamic patterns of size variation, gene content, and genome rearrangements. Phylogenomic analyses are improving resolution of relationships, and uncovering novel lineages as new plastomes continue to be characterized. To gain further insight into the evolution of the chlorophyte plastome and increase the number of representative plastomes for the Sphaeropleales, this study presents two fully sequenced plastomes from the green algal family Hydrodictyaceae (Sphaeropleales, Chlorophyceae), one from Hydrodictyon reticulatum and the other from Pediastrum duplex.

Methods
Genomic DNA from Hydrodictyon reticulatum and Pediastrum duplex was subjected to Illumina paired-end sequencing and the complete plastomes were assembled for each. Plastome size and gene content were characterized and compared with other plastomes from the Sphaeropleales. Homology searches using BLASTX were used to characterize introns and open reading frames (orfs) ≥ 300 bp. A phylogenetic analysis of gene order across the Sphaeropleales was performed.

Results
The plastome of Hydrodictyon reticulatum is 225,641 bp and Pediastrum duplex is 232,554 bp. The plastome structure and gene order of H. reticulatum and P. duplex are more similar to each other than to other members of the Sphaeropleales. Numerous unique open reading frames are found in both plastomes and the plastome of P. duplex contains putative viral protein genes, not found in other Sphaeropleales plastomes. Gene order analyses support the monophyly of the Hydrodictyaceae and their sister relationship to the Neochloridaceae.

Discussion
The complete plastomes of Hydrodictyon reticulatum and Pediastrum duplex, representing the largest of the Sphaeropleales sequenced thus far, once again highlight the variability in size, architecture, gene order and content across the Chlorophyceae. Novel intron insertion sites and unique orfs indicate recent, independent invasions into each plastome, a hypothesis testable with an expanded plastome investigation within the Hydrodictyaceae.
Calibration of the B/Ca proxy in the planktic foraminifer Orbulina universa to Paleocene seawater conditions
Authors: Haynes Laura L. , Hönisch Bärbel , Dyez Kelsey A. , Holland Kate , Rosenthal Yair , Fish Carina R. , Subhas Adam V. , Rae James W. B. 
Published: May 2017

AbstractThe B/Ca ratio of planktic foraminiferal calcite, a proxy for the surface ocean carbonate system, displays large negative excursions during the Paleocene‐Eocene Thermal Maximum (PETM, 55.9 Ma), consistent with rapid ocean acidification at that time. However, the B/Ca excursion measured at the PETM exceeds a magnitude that modern pH calibrations can explain. Numerous other controls on the proxy have been suggested, including foraminiferal growth rate and the total concentration of dissolved inorganic carbon (DIC). Here we present new calibrations for B/Ca versus the combined effects of pH and DIC in the symbiont‐bearing planktic foraminifer Orbulina universa, grown in culture solutions with simulated Paleocene seawater elemental composition (high [Ca], low [Mg], and low total boron concentration ([B]T). We also investigate the isolated effects of low seawater [B]T, high [Ca], reduced symbiont photosynthetic activity, and average shell growth rate on O. universa B/Ca in order to further understand the proxy systematics and to determine other possible influences on the PETM records. We find that average shell growth rate does not appear to determine B/Ca in high calcite saturation experiments. In addition, our “Paleocene” calibration shows higher sensitivity than the modern calibration at low [B(OH)4−]/DIC. Given a large DIC pulse at the PETM, this amplification of the B/Ca response can more fully explain the PETM B/Ca excursion. However, further calibrations with other foraminifer species are needed to determine the range of foraminifer species‐specific proxy sensitivities under these conditions for quantitative reconstruction of large carbon cycle perturbations.
Time scales of relaxation dynamics during transient conditions in two‐phase flow
Authors: Schlüter Steffen , Berg Steffen , Li Tianyi , Vogel Hans‐Jörg , Wildenschild Dorthe 
Published: May 2017

AbstractThe relaxation dynamics toward a hydrostatic equilibrium after a change in phase saturation in porous media is governed by fluid reconfiguration at the pore scale. Little is known whether a hydrostatic equilibrium in which all interfaces come to rest is ever reached and which microscopic processes govern the time scales of relaxation. Here we apply fast synchrotron‐based X‐ray tomography (X‐ray CT) to measure the slow relaxation dynamics of fluid interfaces in a glass bead pack after fast drainage of the sample. The relaxation of interfaces triggers internal redistribution of fluids, reduces the surface energy stored in the fluid interfaces, and relaxes the contact angle toward the equilibrium value while the fluid topology remains unchanged. The equilibration of capillary pressures occurs in two stages: (i) a quick relaxation within seconds in which most of the pressure drop that built up during drainage is dissipated, a process that is to fast to be captured with fast X‐ray CT, and (ii) a slow relaxation with characteristic time scales of 1–4 h which manifests itself as a spontaneous imbibition process that is well described by the Washburn equation for capillary rise in porous media. The slow relaxation implies that a hydrostatic equilibrium is hardly ever attained in practice when conducting two‐phase experiments in which a flux boundary condition is changed from flow to no‐flow. Implications for experiments with pressure boundary conditions are discussed.
Improved characterization of heterogeneous permeability in saline aquifers from transient pressure data during freshwater injection
Authors: Kang Peter K. , Lee Jonghyun , Fu Xiaojing , Lee Seunghak , Kitanidis Peter K. , Juanes Ruben 
Published: May 2017

AbstractManaging recharge of freshwater into saline aquifers requires accurate estimation of the heterogeneous permeability field for maximizing injection and recovery efficiency. Here we present a methodology for subsurface characterization in saline aquifers that takes advantage of the density difference between the injected freshwater and the ambient saline groundwater. We combine high‐resolution forward modeling of density‐driven flow with an efficient Bayesian geostatistical inversion algorithm. In the presence of a density difference between the injected and ambient fluids due to differences in salinity, the pressure field is coupled to the spatial distribution of salinity. This coupling renders the pressure field transient: the time evolution of the salinity distribution controls the density distribution which then leads to a time‐evolving pressure distribution. We exploit this coupling between pressure and salinity to obtain an improved characterization of the permeability field without multiple pumping tests or additional salinity measurements. We show that the inversion performance improves with an increase in the mixed convection ratio—the relative importance between viscous forces from injection and buoyancy forces from density difference. Our work shows that measuring transient pressure data at multiple sampling points during freshwater injection into saline aquifers can be an effective strategy for aquifer characterization, key to the successful management of aquifer recharge.
In situ characterization of wettability alteration and displacement mechanisms governing recovery enhancement due to low‐salinity waterflooding
Authors: Khishvand M. , Alizadeh A. H. , Oraki Kohshour I. , Piri M. , Prasad R. S. 
Published: May 2017

AbstractA series of micro‐scale core‐flooding experiments were performed on reservoir core samples at elevated temperature and pressure conditions to develop better insights into wettability alteration and pore‐scale displacement mechanisms taking place during low‐salinity waterflooding (LSWF). Two individual miniature core samples were cut from a preserved reservoir whole core, saturated to establish initial reservoir fluid saturation conditions, and subsequently waterflooded with low‐salinity and high‐salinity brines. A third miniature sister core sample was also cut, solvent‐cleaned, and subjected to a dynamic wettability restoration process (to reestablish native state wettability) and then a low‐salinity waterflood. All samples were imaged during the experiments using a micro‐CT scanner to obtain fluid occupancy maps and measure in situ oil‐water contact angles. The results of the experiments performed on the preserved core samples show a significantly improved performance of low‐salinity waterflooding compared to that of high‐salinity waterflooding (HSWF). Pore‐scale contact angle measurements provide direct evidence of wettability alteration from weakly oil‐wet toward weakly water‐wet conditions during LSWF, whereas contact angles measured during HSWF remain unchanged. We believe that the reduction in oil‐water contact angles toward increased water‐wetness lowers the threshold water pressure needed to displace oil from some medium‐sized pore elements. Contact angles measured during the dynamic wettability restoration process show an equilibrium wettability state very similar to the initial one observed in the preserved samples. This indicates that drilling fluid contaminants had a negligible effect on the reservoir rock wettability. The experimental results also reveal similarities between saturation trends for the preserved‐LSWF and restored‐LSWF tests.
Geological entropy and solute transport in heterogeneous porous media
Authors: Bianchi Marco , Pedretti Daniele 
Published: May 2017

AbstractWe propose a novel approach to link solute transport behavior to the physical heterogeneity of the aquifer, which we fully characterize with two measurable parameters: the variance of the log K values (
), and a new indicator (HR) that integrates multiple properties of the K field into a global measure of spatial disorder or geological entropy. From the results of a detailed numerical experiment considering solute transport in K fields representing realistic distributions of hydrofacies in alluvial aquifers, we identify empirical relationship between the two parameters and the first three central moments of the distributions of arrival times of solute particles at a selected control plane. The analysis of experimental data indicates that the mean and the variance of the solutes arrival times tend to increase with spatial disorder (i.e., HR increasing), while highly skewed distributions are observed in more orderly structures (i.e., HR decreasing) or at higher
. We found that simple closed‐form empirical expressions of the bivariate dependency of skewness on HR and
can be used to predict the emergence of non‐Fickian transport in K fields considering a range of structures and heterogeneity levels, some of which based on documented real aquifers. The accuracy of these predictions and in general the results from this study indicate that a description of the global variability and structure of the K field in terms of variance and geological entropy offers a valid and broadly applicable approach for the interpretation and prediction of transport in heterogeneous porous media.
Global ULF waves generated by a hot flow anomaly
Authors: Zhao L. L. , Zhang H. , Zong Q. G. 
Published: May 2017

AbstractHot flow anomalies (HFAs), which are frequently observed near Earth's bow shock, are phenomena resulting from the interaction between interplanetary discontinuities and Earth's bow shock. Such transient phenomena upstream the bow shock can cause significant deformation of the bow shock and the magnetosphere, generating traveling convection vortices, field‐aligned currents, and ULF waves in the Earth's magnetosphere. A large HFA (4.9 RE) was observed by Cluster on 27 April 2008. Nearly monochromatic Pc 3 ULF waves generated by the HFA were observed by multiple spacecrafts and ground stations. The ULF waves show characteristics of standing Alfvén waves. The wave power of the poloidal mode of the generated ULF waves is stronger than that of the toroidal mode. Polarization rotation from the poloidal mode to the toroidal mode is also observed. The Pc 3 ULF waves generated by the HFA were observed at dawn, noon, dusk sectors, and nightside, indicating that the Pc 3 ULF wave response of the magnetosphere to the HFA is global. Our results show that the impact of HFAs to the magnetosphere is much stronger than what we thought before.
Statistical properties of solar wind reconnection exhausts
Authors: Mistry R. , Eastwood J. P. , Phan T. D. , Hietala H. 
Published: May 2017

AbstractThe solar wind provides an excellent opportunity to study the exhausts that form as a result of symmetric guide field reconnection, where spacecraft rapidly cross the exhausts far downstream of the X line. We study the statistical properties of solar wind exhausts through a superposed epoch analysis of 188 events observed at 1 AU using the Wind spacecraft. These events span a range of guide fields of 0 to 10 times the reconnecting magnetic field and inflow region plasma beta of 0.1 to 6.6. This analysis reveals that the out‐of‐plane magnetic field is enhanced within solar wind exhausts. Furthermore, the amount by which the plasma density and ion temperature increase from inflow region to exhaust region is found to be a function of the inflow region plasma beta and reconnection guide field, which explains the lack of these enhancements in a subset of previous observations. This dependence is consistent with the scaling of ion heating with inflow region Alfven speed, which is measured to be consistent with previous observations in the solar wind and at the magnetopause.
Kinematics and dynamics of the Pamir, Central Asia: Quantifying surface deformation and force balance in an intracontinental subduction zone
Authors: Jay Cassidy N. , Flesch Lucy M. , Bendick Rebecca O. 
Published: May 2017

AbstractKinematic and dynamic models quantify deformation and force balance in the Pamir, a region undergoing the rare and poorly understood process of intracontinental subduction. We constrain a detailed kinematic model with 506 recent GPS velocities and Quaternary fault slip rates and show that the Pamir is organized like the Himalaya and Tibet, with regions of (1) localized strain rate ≥100e‐9/year along the Pamir Frontal Thrust System (the subduction interface), similar to the Himalaya, and (2) distributed north‐south compression and east‐west extension, similar to Tibet. Through standard thin viscous sheet methods we demonstrate that the lithospheric force balance in the Pamir is a combination of stresses caused by gravitational potential energy and India‐Eurasia convergence accommodated at a subduction interface, in this case the Pamir Frontal Thrust System. We find that strain rate and deviatoric stress patterns near the Pamir Frontal Thrust System are characteristic of a mature subduction zone, despite its initiation in continental lithosphere. Although the Pamir and Tibet are kinematically and dynamically similar, the Pamir is stiffer overall than Tibet, perhaps due to the presence of the highly arcuate, geometrically stiffened continental slab at depth.
Partitioning into hazard subregions for regional peaks‐over‐threshold modeling of heavy precipitation
Authors: Carreau J. , Naveau P. , Neppel L. 
Published: May 2017

AbstractThe French Mediterranean is subject to intense precipitation events occurring mostly in autumn. These can potentially cause flash floods, the main natural danger in the area. The distribution of these events follows specific spatial patterns, i.e., some sites are more likely to be affected than others. The peaks‐over‐threshold approach consists in modeling extremes, such as heavy precipitation, by the generalized Pareto (GP) distribution. The shape parameter of the GP controls the probability of extreme events and can be related to the hazard level of a given site. When interpolating across a region, the shape parameter should reproduce the observed spatial patterns of the probability of heavy precipitation. However, the shape parameter estimators have high uncertainty which might hide the underlying spatial variability. As a compromise, we choose to let the shape parameter vary in a moderate fashion. More precisely, we assume that the region of interest can be partitioned into subregions with constant hazard level. We formalize the model as a conditional mixture of GP distributions. We develop a two‐step inference strategy based on probability weighted moments and put forward a cross‐validation procedure to select the number of subregions. A synthetic data study reveals that the inference strategy is consistent and not very sensitive to the selected number of subregions. An application on daily precipitation data from the French Mediterranean shows that the conditional mixture of GPs outperforms two interpolation approaches (with constant or smoothly varying shape parameter).