177 research outputs found

    A grounded theory of female adolescents' dating experiences and factors influencing safety: the dynamics of the Circle

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    <p>Abstract</p> <p>Background</p> <p>This paper describes the nature and characteristics of the dating relationships of adolescent females, including any of their experiences of abuse.</p> <p>Methods</p> <p>A grounded theory approach was used with 22 theoretically sampled female adolescents ages 15–18.</p> <p>Results</p> <p>Several important themes emerged: Seven stages of dating consistently described the relationships of female adolescents. A circle consisting of two interacting same sex peer groups provided structure for each teen as they navigated the dating course. The circle was the central factor affecting a female adolescent's potential for risk or harm in dating relationships. Teens defined abuse as an act where the intention is to hurt. Having once succumbed to sexual pressure, teens felt unable to refuse sex in subsequent situations.</p> <p>Conclusion</p> <p>An awareness of both the stages of dating and the dynamics of the circle will assist health care providers to plan and implement interventions in the female adolescent population. Study findings on factors and influences that support non-abusive versus abusive relationship might help identify female teens at risk and/or support interventions aimed at preventing dating violence.</p

    Binary and Millisecond Pulsars at the New Millennium

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    We review the properties and applications of binary and millisecond pulsars. Our knowledge of these exciting objects has greatly increased in recent years, mainly due to successful surveys which have brought the known pulsar population to over 1300. There are now 56 binary and millisecond pulsars in the Galactic disk and a further 47 in globular clusters. This review is concerned primarily with the results and spin-offs from these surveys which are of particular interest to the relativity community.Comment: 59 pages, 26 figures, 5 tables. Accepted for publication in Living Reviews in Relativity (http://www.livingreviews.org

    DinĂąmica populacional de Bemisia tabaci biĂłtipo B em tomate monocultivo e consorciado com coentro sob cultivo orgĂąnico e convencional.

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    A mosca-branca Bemisia tabaci BiĂłtipo B (Hemiptera: Aleyrodidae), Ă© um herbĂ­voro de difĂ­cil controle devido Ă  alta plasticidade genotĂ­pica da espĂ©cie. No tomateiro pode causar danos severos principalmente pela transmissĂŁo de diversas viroses. O manejo do sistema de produção e o consĂłrcio de culturas podem ter um efeito direto nas populaçÔes desse herbĂ­voro, sem que seja necessĂĄria a aplicação de inseticidas. Avaliou-se a influĂȘncia dos sistemas de produção orgĂąnico e convencional e o consĂłrcio tomate-coentro na dinĂąmica populacional da mosca-branca no campo experimental da Embrapa Hortaliças, de maio a setembro/06. O monitoramento dos adultos da mosca-branca e de seus inimigos naturais foi realizado utilizando-se armadilhas adesivas amarelas fixadas nas bordas e no interior das parcelas experimentais e a amostragem de ninfas foi realizada por observação direta das folhas de tomate no campo. Embora as populaçÔes ao redor dos diferentes tratamentos fossem equivalentes, a abundĂąncia de adultos de mosca-branca foi significativamente menor nas parcelas de tomate consorciado com coentro, tanto no sistema convencional como orgĂąnico. Apenas o consĂłrcio tomatecoentro em sistema orgĂąnico apresentou redução significativa na quantidade de ninfas por planta em relação aos demais tratamentos. Os inimigos naturais foram significativamente mais abundantes em sistema orgĂąnico e foi verificada uma correlação negativa da abundĂąncia dos inimigos naturais e a quantidade de ninfas por planta. A associação tomate-coentro e o manejo orgĂąnico do agroecossistema favoreceram ao controle biolĂłgico natural da mosca-branca

    Evolution of hepatitis B serological markers in HIV coinfected patients: a case study

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    ABSTRACT OBJECTIVE To describe the evolution of serological markers among HIV and hepatitis B coinfected patients, with emphasis on evaluating the reactivation or seroreversion of these markers. METHODS The study population consisted of patients met in an AIDS Outpatient Clinic in SĂŁo Paulo State, Brazil. We included in the analysis all HIV-infected and who underwent at least two positive hepatitis B surface antigen serological testing during clinical follow up, with tests taken six months apart. Patients were tested with commercial kits available for hepatitis B serological markers by microparticle enzyme immunoassay. Clinical variables were collected: age, sex, CD4+ T-cell count, HIV viral load, alanine aminotransferase level, exposure to antiretroviral drugs including lamivudine and/or tenofovir. RESULTS Among 2,242 HIV positive patients, we identified 105 (4.7%) patients with chronic hepatitis B. Follow up time for these patients varied from six months to 20.5 years. All patients underwent antiretroviral therapy during follow-up. Among patients with chronic hepatitis B, 58% were hepatitis B &#8220;e&#8221; antigen positive at the first assessment. Clearance of hepatitis B surface antigen occurred in 15% (16/105) of patients with chronic hepatitis B, and 50% (8/16) of these patients presented subsequent reactivation or seroreversion of hepatitis B surface antigen. Among hepatitis B &#8220;e&#8221; antigen positive patients, 57% (35/61) presented clearance of this serologic marker. During clinical follow up, 28.5% (10/35) of those who initially cleared hepatitis B &#8220;e&#8221; antigen presented seroreversion or reactivation of this marker. CONCLUSIONS Among HIV coinfected patients under antiretroviral therapy, changes of HBV serological markers were frequently observed. These results suggest that frequent monitoring of these serum markers should be recommended

    Binary and Millisecond Pulsars

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    We review the main properties, demographics and applications of binary and millisecond radio pulsars. Our knowledge of these exciting objects has greatly increased in recent years, mainly due to successful surveys which have brought the known pulsar population to over 1700. There are now 80 binary and millisecond pulsars associated with the disk of our Galaxy, and a further 103 pulsars in 24 of the Galactic globular clusters. Recent highlights have been the discovery of the first ever double pulsar system and a recent flurry of discoveries in globular clusters, in particular Terzan 5.Comment: 77 pages, 30 figures, available on-line at http://www.livingreviews.org/lrr-2005-

    Caracol, Belize, and Changing Perceptions of Ancient Maya Society

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    Multi-messenger observations of a binary neutron star merger

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    On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ~1.7 s with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of 40+8-8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 Mo. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ~40 Mpc) less than 11 hours after the merger by the One- Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ~9 and ~16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta

    Observation and branching fraction measurement of the decay Ξb- → Λ0 bπ -

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    Precision measurement of CP\it{CP} violation in the penguin-mediated decay Bs0→ϕϕB_s^{0}\rightarrow\phi\phi

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    A flavor-tagged time-dependent angular analysis of the decay Bs0→ϕϕB_s^{0}\rightarrow\phi\phi is performed using pppp collision data collected by the LHCb experiment at % at s=13\sqrt{s}=13 TeV, the center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 6 fb^{-1}. The CP\it{CP}-violating phase and direct CP\it{CP}-violation parameter are measured to be ϕssˉs=−0.042±0.075±0.009\phi_{s\bar{s}s} = -0.042 \pm 0.075 \pm 0.009 rad and ∣λ∣=1.004±0.030±0.009|\lambda|=1.004\pm 0.030 \pm 0.009 , respectively, assuming the same values for all polarization states of the ϕϕ\phi\phi system. In these results, the first uncertainties are statistical and the second systematic. These parameters are also determined separately for each polarization state, showing no evidence for polarization dependence. The results are combined with previous LHCb measurements using pppp collisions at center-of-mass energies of 7 and 8 TeV, yielding ϕssˉs=−0.074±0.069\phi_{s\bar{s}s} = -0.074 \pm 0.069 rad and ∣lambda∣=1.009±0.030|lambda|=1.009 \pm 0.030. This is the most precise study of time-dependent CP\it{CP} violation in a penguin-dominated BB meson decay. The results are consistent with CP\it{CP} symmetry and with the Standard Model predictions.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2023-001.html (LHCb public pages

    Molecular mechanisms of cell death: recommendations of the Nomenclature Committee on Cell Death 2018.

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    Over the past decade, the Nomenclature Committee on Cell Death (NCCD) has formulated guidelines for the definition and interpretation of cell death from morphological, biochemical, and functional perspectives. Since the field continues to expand and novel mechanisms that orchestrate multiple cell death pathways are unveiled, we propose an updated classification of cell death subroutines focusing on mechanistic and essential (as opposed to correlative and dispensable) aspects of the process. As we provide molecularly oriented definitions of terms including intrinsic apoptosis, extrinsic apoptosis, mitochondrial permeability transition (MPT)-driven necrosis, necroptosis, ferroptosis, pyroptosis, parthanatos, entotic cell death, NETotic cell death, lysosome-dependent cell death, autophagy-dependent cell death, immunogenic cell death, cellular senescence, and mitotic catastrophe, we discuss the utility of neologisms that refer to highly specialized instances of these processes. The mission of the NCCD is to provide a widely accepted nomenclature on cell death in support of the continued development of the field
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