Risk evaluations and condom use decisions of homeless youth: a multi-level qualitative investigation.

BackgroundHomeless youth are at higher risk for sexually transmitted infections and unwanted pregnancy than non-homeless youth. However, little is known about how they evaluate risk within the context of their sexual relationships. It is important to understand homeless youths' condom use decisions in light of their sexual relationships because condom use decisions are influenced by relationship dynamics in addition to individual attitudes and event circumstances. It is also important to understand how relationship level factors, sexual event circumstances, and individual characteristics compare and intersect.MethodsTo explore these issues, we conducted semi-structured interviews with 37 homeless youth in Los Angeles County in 2011 concerning their recent sexual relationships and analyzed the data using systematic methods of team-based qualitative data analysis.ResultsWe identified themes of risk-related evaluations and decisions at the relationship/partner, event, and individual level. We also identified three different risk profiles that emerged from analyzing how different levels of risk intersected across individual respondents. The three profiles included 1) Risk Takers, who consistently engage in risk and have low concern about consequences of risk behavior, 2) Risk Avoiders, who consistently show high concern about protection and consistently avoid risk, and 3) Risk Reactors, those who are inconsistent in their concerns about risk and protection and mainly take risks in reaction to relationship and event circumstances.ConclusionsInterventions targeting homeless youth should reflect multiple levels of risk behavior and evaluation in order to address the diversity of risk profiles. Relationship/partner-, event-, and individual-level factors are all important but have different levels of importance for different homeless youth. Interventions should be tailored to address the most important factor contributing to homeless youth reproductive needs

Advancing Aircraft Operations in a Net-Centric Environment with the Incorporation of Increasingly Autonomous Systems and Human Teaming

NextGen has begun the modernization of the nations air transportation system, with goals to improve system safety, increase operation efficiency and capacity, provide enhanced predictability, resilience and robustness. With these improvements, NextGen is poised to handle significant increases in air traffic operations, more than twice the number recorded in 2016, by 2025.1 NextGen is evolving toward collaborative decision-making across many agents, including automation, by use of a Net-Centric architecture, which in itself creates a very complex environment in which the navigation and operation of aircraft are to take place. An intricate environment such as this, coupled with the expected upsurge of air traffic operations generates concern respecting the ability of the human-agent to both fly and manage aircraft within. Therefore, it is both necessary and practical to begin the process of increasingly autonomous systems within the cockpit that will act independently to assist the human-agent achieve the overall goal of NextGen. However, the straightforward technological development and implementation of intelligent machines into the cockpit is only part of what is necessary to maintain, at minimum, or improve human-agent functionality, as desired, while operating in NextGen. The full integration of Increasingly Autonomous Systems (IAS) within the cockpit can only be accomplished when the IAS works in concert with the human, formulating trust between the two, thereby establishing a team atmosphere. Imperative to cockpit implementation is ensuring the proper performance of the IAS by the development team and the human-agent with which it will be paired when given a specific piloting, navigation, or observational task. Described in this paper are the steps taken, at NASA Langley Research Center, during the second and third phases of the development of an IAS, the Traffic Data Manager (TDM), its verification and validation by human-agents, and the foundational development of Human Autonomy Teaming (HAT) between the two

Graphical User Interface Development and Design to Support Airport Runway Configuration Management

The objective of this effort was to develop a graphical user interface (GUI) for the National Aeronautics and Space Administration's (NASA) System Oriented Runway Management (SORM) decision support tool to support runway management. This tool is expected to be used by traffic flow managers and supervisors in the Airport Traffic Control Tower (ATCT) and Terminal Radar Approach Control (TRACON) facilities

High-pressure characterization of multifunctional CrVO4

[EN] The structural stability and physical properties of CrVO(4)under compression were studied by x-ray diffraction, Raman spectroscopy, optical absorption, resistivity measurements, andab initiocalculations up to 10 GPa. High-pressure x-ray diffraction and Raman measurements show that CrVO(4)undergoes a phase transition from the ambient pressure orthorhombic CrVO4-type structure (Cmcm space group, phase III) to the high-pressure monoclinic CrVO4-V phase, which is proposed to be isomorphic to the wolframite structure. Such a phase transition (CrVO4-type -> wolframite), driven by pressure, also was previously observed in indium vanadate. The crystal structure of both phases and the pressure dependence in unit-cell parameters, Raman-active modes, resistivity, and electronic band gap, are reported. Vanadium atoms are sixth-fold coordinated in the wolframite phase, which is related to the collapse in the volume at the phase transition. Besides, we also observed drastic changes in the phonon spectrum, a drop of the band-gap, and a sharp decrease of resistivity. All the observed phenomena are explained with the help of first-principles calculations.This work was supported by the Spanish Ministry of Science, Innovation and Universities under Grants MAT2016-75586-C4-1/2-P, FIS2017-83295-P and RED2018-102612-T (MALTA Consolider-Team network) and by Generalitat Valenciana under Grant Prometeo/2018/123 (EFIMAT). PB and AV acknowledge the Kempe Foundation and the Knut och Alice Wallenberg Foundation for their financial support. JAS also acknowledges Ramon y Cajal program for funding support through RYC-2015-17482. The x-ray diffraction measurements were carried out with the support of the Diamond Light Source at the I15 beamline under proposal no. 683. The authors thank A Kleppe for technical support during the experiments. SL-M thanks CONACYT of Mexico for financial support through the program 'Catedras para jovenes Investigadores'. Also, SL-M gratefully acknowledges the computing time granted by LANCAD and CONACYT on the supercomputer Miztli at LSVP DGTIC UNAM. Besides, some of the computing for this project was performed with the resources of the IPICYT Supercomputing National Center for Education & Research, Grant TKII-R2020-SLM1.Botella, P.; López-Moreno, S.; Errandonea, D.; Manjón, F.; Sans-Tresserras, JÁ.; Vie, D.; Vomiero, A. (2020). High-pressure characterization of multifunctional CrVO4. Journal of Physics Condensed Matter. 32(38):1-14. https://doi.org/10.1088/1361-648X/ab9408S114323

Thermal Conductivity, Heat Sources and Temperature Profiles of Li-ion Secondary Batteries

We measure and report the thermal conductivity of several commercial and non-commercial Li-ion secondary battery electrode materials, with and without electrolyte solvents. We also measure the Tafel potential, the ohmic resistance, reaction entropy and external temperature of a commercial pouch cell secondary Li-ion battery. Finally we combine all the experimentally obtained data in a thermal Fourier model and discuss the corresponding internal and external temperature profiles during charging and discharging. Electrochemical accumulators and power sources can be both very effective and efficient energy converters. However, as one seeks to intensify both volumetric and specific capacity the heat of these is an inevitable topic in engineering. Moreover, in order to increase performance, the electrodes are necessarily made porous, so that the active specific surface can be increased. In doing so, the thermal conductivity can be lowered by several orders of magnitude. Literature describing thermal conductivity of this property of different Li-ion electrodes is scarse, according to recent reviews e.g. [1], although it is very important. For the ex-situ thermal conductivity measurements we chose commercial electrode materials and for the temperature profile measurements and the electrochemical characterisation we chose a commercial Li-ion pouch cell battery. The electrode materials that we investigated with respect to thermal conductivity were a commercial cathode material (LiCoO 3 ) and a commercial anode material (SLP50). These materials were measured with in an already established procedure [2], both as dry pristine electrode and with a surplus of an electrolyte solvent. The commercial battery was characterised by classical charge and discharge cycling at different current rates.. These experiments were performed in a temperature regulated cabinet with a thermocouple on the battery surface and another in the ambient air. Thus all information required to model the battery's internal and external temperature profiles were collected for the modelling part. The thermal conductivity of dry and soaked electrode material was found to be 0.30 ±0.01 and 0.89±0.04 W K -1 m -1 for the anode material and 0.36±0.003 and 1.10±0.06 for the cathode material. For all materials examined it was found that adding electrolyte solvent increased the thermal conductivity by at least a factor of three. Measuring and combining the surface and the ambient temperatures of an air cooled commercial pouch cell battery at ±2°C, the electric heat sources, and the thermal conductivity of the electrode components made it possible to estimate internal and external temperature profiles at any current density. At 12C charging rate (corresponding to 5 minutes complete charging) the internal temperature differences was estimated to be in the range of 3-4 K, depending on the electrode thermal conductivity. The external temperature drop in air flowing (by forced convection) at the battery surface was estimated to nearly 70K. Thus it is clear that though it is the external temperature gradients that need the most attention with respect to engineered cooling, also internal temperatures become significant at large current rates

Congenital dislocation of the hip: Optimal screening strategies in 2014

AbstractA prospective multi-centre nationwide study of patients with congenital dislocation of the hip (CDH) diagnosed after 3 months of age was conducted with support from the French Society for Paediatric Orthopaedics (Société Française d’Orthopédie Pédiatrique [SoFOP]), French Organisation for Outpatient Paediatrics (Association Française de Pédiatrie Ambulatoire [AFPA]), and French-Speaking Society for Paediatric and Pre-Natal Imaging (Société Francophone d’Imagerie Pédiatrique et Prénatale [SFIPP]). The results showed inadequacies in clinical screening for CDH that were patent when assessed quantitatively and probably also present qualitatively. These findings indicate a need for a communication and educational campaign aimed at highlighting good clinical practice guidelines in the field of CDH screening. The usefulness of routine ultrasound screening has not been established. The findings from this study have been used by the authors and French National Health Authority (Haute Autorité de Santé [HAS]) to develop recommendations about CDH screening. There is an urgent need for a prospective randomised multi-centre nationwide study, which should involve primary-care physicians

Vitamin E and selenium plasma concentrations in weanling pigs under field conditions in Norwegian pig herds

BACKGROUND: The status of α-tocopherol (vit E) and selenium (Se) has been shown to influence disease resistance in pigs, and may be important for the health of weanling pigs. METHODS: Plasma levels of both vit E and Se were followed in weanling pigs under field conditions in six Norwegian pig herds. Plasma vit E and Se were measured in 3 sows from each herd and 4 piglets in the litter of each sow at the day before weaning (day -1); and in the same piglets at days 4, 8 and 18 after weaning. RESULTS: Mean plasma vit E was 4.0 μg/ml in the sows and 2.6 μg/ml in the piglets at day -1, fell to 1.6 μg/ml in the weanling pigs at day 4, and remained low. Mean plasma Se was 0.22 μg/g in the sows and 0.08 μg/g in the piglets at day -1, rose to 0.10 μg/g in the weanlings at day 4, and continued rising. CONCLUSION: The results suggest that vit E and Se supplementation to piglets and weanling pigs in Norway may still be suboptimal, but that levels of the two nutrients partially compensate for each other in the weaning period