810 research outputs found

    Adolescent vulnerability, sexual health, and the NP’s role in health advocacy

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    PurposeTo describe adolescents as a vulnerable population with unique healthcare needs, especially in relation to their sexual risk‐taking behaviors; and to explicate the necessity of nurse practitioners (NPs) advocating for youth‐friendly services and policies to meet adolescents’ sexual and reproductive healthcare needs.Data sourcesCINAHL, Medline, PsychInfo, and PsychArticle databases were searched to identify theoretical and empirical literature regarding adolescence, vulnerability, sexual health outcomes, barriers to accessing reproductive health services, what it means to be youth friendly, and health advocacy to meet the health needs of adolescents.ConclusionsAdolescents’ health needs may not be fully met in traditional healthcare settings. Lack of access to youth‐friendly sexual and reproductive health services increases adolescents’ risks for poor health outcomes including sexually transmitted disease and unplanned pregnancy. Clinic, state, and national policies can create barriers for adolescents in obtaining sexual health services.Implications for practiceNPs are philosophically and educationally prepared to be leaders in improving adolescent health outcomes. NPs can directly provide youth‐friendly care as well as advocate for youth‐friendly practices within their health system. In addition, NPs are well positioned to be leaders in advocating for state and national policies that improve adolescents’ access to appropriate sexual and reproductive health care.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/133601/1/jaan12331.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/133601/2/jaan12331_am.pd

    Ultraslow Electron Spin Dynamics in GaAs Quantum Wells Probed by Optically Pumped NMR

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    Optically pumped nuclear magnetic resonance (OPNMR) measurements were performed in two different electron-doped multiple quantum well samples near the fractional quantum Hall effect ground state nu=1/3. Below 0.5K, the spectra provide evidence that spin-reversed charged excitations of the nu=1/3 ground state are localized over the NMR time scale of ~40 microseconds. Furthermore, by varying NMR pulse parameters, the electron spin temperature (as measured by the Knight shift) could be driven above the lattice temperature, which shows that the value of the electron spin-lattice relaxation time lies between 100 microseconds and 500 milliseconds at nu=1/3.Comment: 6 pages (REVTEX), 6 eps figures embedded in text; published version; minor changes to match published versio

    СКЛАДОВІ ІНФОРМАЦІЙНОГО ЗАБЕЗПЕЧЕННЯ АВТОМАТИЗОВАНОЇ СИСТЕМИ ПІДТРИМКИ ПРИЙНЯТТЯ РІШЕНЬ ПРИ УПРАВЛІННІ НАВЧАЛЬНИМ ПРОЦЕСОМ

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    Stages of development of information technology and components of information management of the automated decision support system for control of educational process in higher educational establishments were presented.Предложены этапы разработки информационной технологии и состав-ляющие информационного обеспечения автоматизированной системы под-держки принятия решений при управлении учебным процессом в высших учебных заведениях.Запропоновано етапи розробки інформаційної технології та складові ін-формаційного забезпечення автоматизованої системи підтримки прий¬няття рішень при управлінні навчальним процесом у вищих закладах освіт

    Spectroscopic Evidence for the Localization of Skyrmions near Nu=1 as T->0

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    Optically pumped nuclear magnetic resonance measurements of Ga-71 spectra were carried out in an n-doped GaAs/Al0.1Ga0.9As multiple quantum well sample near the integer quantum Hall ground state Nu=1. As the temperature is lowered (down to T~0.3 K), a ``tilted plateau'' emerges in the Knight shift data, which is a novel experimental signature of quasiparticle localization. The dependence of the spectra on both T and Nu suggests that the localization is a collective process. The frozen limit spectra appear to rule out a 2D lattice of conventional skyrmions.Comment: 4 pages (REVTEX), 5 eps figures embedded in text, published versio

    Skyrmion Dynamics and NMR Line Shapes in QHE Ferromagnets

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    The low energy charged excitations in quantum Hall ferromagnets are topological defects in the spin orientation known as skyrmions. Recent experimental studies on nuclear magnetic resonance spectral line shapes in quantum well heterostructures show a transition from a motionally narrowed to a broader `frozen' line shape as the temperature is lowered at fixed filling factor. We present a skyrmion diffusion model that describes the experimental observations qualitatively and shows a time scale of 50μsec\sim 50 \mu{\rm sec} for the transport relaxation time of the skyrmions. The transition is characterized by an intermediate time regime that we demonstrate is weakly sensitive to the dynamics of the charged spin texture excitations and the sub-band electronic wave functions within our model. We also show that the spectral line shape is very sensitive to the nuclear polarization profile along the z-axis obtained through the optical pumping technique.Comment: 6 pages, 4 figure

    Tunneling into Ferromagnetic Quantum Hall States: Observation of a Spin Bottleneck

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    We explore the characteristics of equilibrium tunneling of electrons from a 3D electrode into a high mobility 2D electron system. For most 2D Landau level filling factors, we find that tunneling can be characterized by a single, well-defined tunneling rate. However, for spin-polarized quantum Hall states (nu = 1, 3 and 1/3) tunneling occurs at two distinct rates that differ by up to 2 orders of magnitude. The dependence of the two rates on temperature and tunnel barrier thickness suggests that slow in-plane spin relaxation creates a bottleneck for tunneling of electrons.Comment: 5 pages, 4 figures, submitted to PR

    Optically Pumped NMR Measurements of the Electron Spin Polarization in GaAs Quantum Wells near Landau Level Filling Factor nu=1/3

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    The Knight shift of Ga-71 nuclei is measured in two different electron-doped multiple quantum well samples using optically pumped NMR. These data are the first direct measurements of the electron spin polarization, P(nu,T)=/max, near nu=1/3. The P(T) data at nu=1/3 probe the neutral spin-flip excitations of a fractional quantum Hall ferromagnet. In addition, the saturated P(nu) drops on either side of nu=1/3, even in a Btot=12 Tesla field. The observed depolarization is quite small, consistent with an average of about 0.1 spin-flips per quasihole (or quasiparticle), a value which does not appear to be explicable by the current theoretical understanding of the FQHE near nu=1/3.Comment: 4 pages (REVTEX), 5 eps figures embedded in text; minor changes, published versio

    Cluster formation restricts dynamic nuclear polarization of xenon in solid mixtures

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    During dynamic nuclear polarization (DNP) at 1.5 K and 5 T, (129)Xe nuclear magnetic resonance (NMR) spectra of a homogeneous xenon/1-propanol/trityl-radical solid mixture exhibit a single peak, broadened by (1)H neighbors. A second peak appears upon annealing for several hours at 125 K. Its characteristic width and chemical shift indicate the presence of spontaneously formed pure Xe clusters. Microwave irradiation at the appropriate frequencies can bring both peaks to either positive or negative polarization. The peculiar time evolution of (129)Xe polarization in pure Xe clusters during DNP can be modelled as an interplay of spin diffusion and T(1) relaxation. Our simple spherical-cluster model offers a sensitive tool to evaluate major DNP parameters in situ, revealing a severe spin-diffusion bottleneck at the cluster boundaries and a significant sample overheating due to microwave irradiation. Subsequent DNP system modifications designed to reduce the overheating resulted in four-fold increase of (129)Xe polarization, from 5.3% to 21%

    NMR Determination of 2D Electron Spin Polarization at ν=1/2\nu=1/2

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    Using a `standard' NMR spin-echo technique we determined the spin polarization of two-dimensional electrons, confined to GaAs quantum wells, from the hyperfine shift of Ga nuclei in the wells. Concentrating on the temperature and magnetic field dependencies of spin polarization at Landau level filling factor ν=1/2\nu =1/2, we find that the results are described well by a simple model of non-interacting composite fermions, although some inconsistencies remain when the two-dimensional electron system is tilted in the magnetic field.Comment: 4 pages (REVTEX) AND 4 figures (PS

    Web Vulnerability Study of Online Pharmacy Sites

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    Consumers are increasingly using online pharmacies, but these sites may not provide an adequate level of security with the consumers’ personal data. There is a gap in this research addressing the problems of security vulnerabilities in this industry. The objective is to identify the level of web application security vulnerabilities in online pharmacies and the common types of flaws, thus expanding on prior studies. Technical, managerial and legal recommendations on how to mitigate security issues are presented. The proposed four-step method first consists of choosing an online testing tool. The next steps involve choosing a list of 60 online pharmacy sites to test, and then running the software analysis to compile a list of flaws. Finally, an in-depth analysis is performed on the types of web application vulnerabilities. The majority of sites had serious vulnerabilities, with the majority of flaws being cross-site scripting or old versions of software that have not been updated. A method is proposed for the securing of web pharmacy sites, using a multi-phased approach of technical and managerial techniques together with a thorough understanding of national legal requirements for securing systems
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