622 research outputs found
The 1977 Tundra Fire in the Kokolik River Area of Alaska
Widespread fires occurred on the Seward Peninsula, Alaska, during the summer of 1977. During this period there was also one large natural fire in the northern part of the state. Presumably caused by lightening, it occurred due east of Point Lay and several kilometres southwest of the Kokolik River (69 30 N, 161 50 W) on the boundary between the coastal plain and the northern foothills .... This was the farthest north a fire had ever been fought by the personnel of BLM in Alaska. No tundra fires had previously been reported from this area, .... Climatic conditions in northern and western Alaska during the summer of 1977, ... were apparently ideal for tundra fires. The information on the spread of the fire, as presented in this short paper, was gathered from Landsat imagery, meteorological observations, facts concerning the natural containment of the fire, and investigations of the affected area following the fire
Water Quality Project Evaluation A Handbook for Objectives-Based Evaluation of Water Quality Projects
PDF pages: 5
Psychological Symptoms Among 2032 Youth Living with HIV: A Multisite Study
This study determined the prevalence and patterns of psychological symptoms in adolescents and young adults living with HIV (YLWH) in medical care and relationships between psychological symptoms, route and duration of infection, and antiretroviral treatment (ART). A clinic-based sample of 2032 YLWH (mean age 20.3 years), recruited from 20 adolescent medicine HIV clinics, completed a cross-sectional survey of health behaviors and psychological symptoms using the Brief Symptom Inventory (BSI). Overall, 17.5% of youth reported psychological symptoms greater than the normative threshold on the Global Severity Index. A wide variety of symptoms were reported. The prevalence of clinical symptoms was significantly greater in youth with behaviorally acquired HIV compared to those with perinatally acquired infection (20.6% vs. 10.8%, OR=2.06 in Multiple Logistic Regression (MLR)), and in those not taking ART that had been prescribed (29. 2% vs. 18.8%, OR=1.68 in MLR). Knowing one's HIV status for more than one year and disclosure of HIV status were not associated with fewer symptoms. A large proportion of YLWH have psychological symptoms and the prevalence is greatest among those with behaviorally acquired infection. The high rate of psychological symptoms for youth not taking ART that is prescribed is a cause for concern. Symptoms do not appear to be a transient reaction to diagnosis of HIV.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140176/1/apc.2014.0113.pd
Fermionic Symmetries: Extension of the two to one Relationship Between the Spectra of Even-Even and Neighbouring Odd mass Nuclei
In the single j shell there is a two to one relationship between the spectra
of certain even-even and neighbouring odd mass nuclei e.g. the calculated
energy levels of J=0^+ states in ^{44}Ti are at twice the energies of
corresponding levels in ^{43}Ti(^{43}Sc) with J=j=7/2. Here an approximate
extension of the relationship is made by adopting a truncated seniority scheme
i.e. for ^{46}Ti and ^{45}Sc we get the relationship if we do not allow the
seniority v=4 states to mix with the v=0 and v=2 states. Better than that, we
get very close to the two to one relationship if seniority v=4 states are
admixed perturbatively. In addition, it is shown that the higher isospin states
do not contain seniority 4 admixtures.Comment: 11 pages, RevTex file and no figures, typos added, references changed
and changed content
Gestational age impacts birth to placental weight ratio and umbilical cord oxygen values with implications for the fetal oxygen margin of safety
Background: We determined the impact of gestational age (GA) from near term to term to post-term on birth/placental weight ratio and cord oxygen values with implications for placental transport efficiency for oxygen, fetal O2 consumption relative to delivery or fractional O2 extraction, and oxygen margin of safety.
Materials and methods: A hospital database was used to obtain birth/placental weight ratios, cord PO2 and other information on patients delivering between Jan 1, 1990 and Jun 15, 2011 with GA \u3e 34 completed weeks (N=69,852). Oxygen saturation was calculated from the cord PO2 and pH data, while fractional O2 extraction was calculated from the oxygen saturation data. The effect of GA grouping on birth/placental weight ratio, cord PO2, O2 saturation, and fractional O2 extraction values, was examined in all patients adjusting for pregnancy and labor/delivery covariates, and in a subset of low-risk patients.
Results: Birth/placental weight ratio and umbilical venous O2 values increased with advancing GA, supporting the conjecture of increasing placental transport efficiency for oxygen. However, umbilical arterial O2 values decreased while fractional O2 extraction increased with successive GA groupings, indicating that fetal O2 consumption must be increasing relative to delivery.
Conclusions: Fetal O2 consumption can be seen as ever ‘outgrowing’ O2 delivery over the last weeks of pregnancy and leading to a continued lowering in systemic oxygen levels. While this lowering in oxygen may trigger feedback mechanisms with survival benefit, the ‘oxygen margin of safety’ will also be lowered increasing perinatal morbidity and mortality which appear to be hypoxia related
Determinants of Multimethod Contraceptive Use in a Sample of Adolescent Women Diagnosed with Psychological Disorders
Objective. Despite recommendations for concurrent use of contraceptives and condoms to prevent unintended pregnancy and STIs, multimethod contraceptive use among women is poor. This study examined individual-, interpersonal-, and environmental-level factors that predict multimethod use among sexually active adolescent women diagnosed with psychological disorders. Methods. This multisite study analyzed data from 288 sexually active adolescent women who provided sociodemographic, psychosocial, and behavioral data related to birth control and condom use. Results. 34.7% of the participants reported multimethod use in the past three months. Controlling for empirically and theoretically relevant covariates, a multivariable logistic regression identified self-efficacy, multiple partners, pregnancy history, parental communication, parental norms about sex, and neighborhood cohesion as significant predictors of multimethod use. Conclusions. While continued targeted messages about multi-method contraceptive use are imperative at the individual level, an uptake in messages targeting interpersonal- and environmental-level factors such as adolescents' parents and the broader community is urgently needed
Multiple Method Contraception Use among African American Adolescents in Four US Cities
We report on African American adolescents' (N = 850; M age = 15.4) contraceptive practices and type of contraception utilized during their last sexual encounter. Respondents completed measures of demographics, contraceptive use, sexual partner type, and ability to select “safe” sexual partners. 40% endorsed use of dual or multiple contraceptive methods; a total of 35 different contraceptive combinations were reported. Perceived ability to select “safe” partners was associated with not using contraception (OR = 1.25), using less effective contraceptive methods (OR = 1.23), or hormonal birth control (OR = 1.50). Female gender predicted hormonal birth control use (OR = 2.33), use of less effective contraceptive methods (e.g., withdrawal; OR = 2.47), and using no contraception (OR = 2.37). Respondents' age and partner type did not predict contraception use. Adolescents used contraceptive methods with limited ability to prevent both unintended pregnancies and STD/HIV. Adolescents who believed their partners posed low risk were more likely to use contraceptive practices other than condoms or no contraception. Reproductive health practitioners are encouraged to help youth negotiate contraceptive use with partners, regardless of the partner's perceived riskiness
Developing family interventions for adolescent HIV prevention in South Africa.
Adolescents and young people account for 40% of all new HIV infections each year, with South Africa one of the hardest hit countries, and having the largest population of people living with HIV. Although adolescent HIV prevention has been delivered through diverse modalities in South Africa, and although family-based approaches for adolescent HIV prevention have great potential for highly affected settings such as South Africa, there is a scarcity of empirically tested family-based adolescent HIV preventive interventions in this setting. We therefore conducted focus groups and in-depth interviews with key informants including clinicians, researchers, and other individuals representing organizations providing HIV and related health services to adolescents and parents (N = 82). We explored family perspectives and interactions around topics such as communication about sex, HIV, and relationships. Participants described aspects of family interactions that presented both challenges and opportunities for family-based adolescent HIV prevention. Parent-child communication on sexual topics were taboo, with these conversations perceived by some adults as an invitation for children to engage in HIV risk behavior. Parents experienced social sanctions for discussing sex and adolescents who asked about sex were often viewed as disrespectful and needing discipline. However, participants also identified context-appropriate strategies for addressing family challenges around HIV prevention including family meetings, communal parenting, building efficacy around parent-adolescent communication around sexual topics, and the need to strengthen family bonding and positive parenting. Findings indicate the need for a family intervention and identify strategies for development of family-based interventions for adolescent HIV prevention. These findings will inform design of a family intervention to be tested in a randomized pilot trial (ClinicalTrials.gov #NCT02432352)
What Have We Learned from RHIC?
In this talk, I present what I believe we have learned from the recent RHIC
heavy ion experiments. The goal of these experiments is to make and study
matter at very high energy densities, greater than an order of magnitude larger
than that of nuclear matter. Have we made such matter? What have we learned
about the properties of this matter? What do we hope and expect to learn in the
future?Comment: 34 figure
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