A mineralogical and geochemical analysis of basaltic lavas from the Zion National Park Region, Southwestern Utah

Includes bibliographical references.In the Transition zone of southwestern Utah, basaltic lavas are geochemically defined as a subduction suite and a plume suite. These predominantly basic lavas are late Cenozoic (<17 Ma) in age, with the two suites related in time and space. This paper suggests a two layer upper mantle model, an upper metasomatized lithospheric layer underlain by an asthenospheric layer, with both alkali basaltic and olivine tholeiitic magmas being generated by varying degrees of partial melting of spinel lherzolite in each individual layer. Due to the greater depth at which asthenospheric magmas are derived, mixing occurs between the alkali basaltic and the olivine tholeiitic magmas during ascent through the lithosphere. Since lithosphere-derived magmas ascend to the crust soon after generation, significantly less mixing occurs, if at all. Time-space relations support such a model.B.S. (Bachelor of Science

Laughlin liquid - Wigner solid transition at high density in wide quantum wells

Assuming that the phase transition between the Wigner solid and the Laughlin liquid is first-order, we compare ground-state energies to find features of the phase diagram at fixed $\nu$. Rather than use the Coulomb interaction, we calculate the effective interaction in a square quantum well, and fit the results to a model interaction with length parameter $\lambda$ roughly proportional to the width of the well. We find a transition to the Wigner solid phase at high density in very wide wells, driven by the softening of the interaction at short distances, as well as the more well-known transition to the Wigner solid at low density, driven by Landau-level mixing.Comment: RevTeX 3.0, 3 Postscript figures appended in uuencoded forma

An exchange-correlation energy for a two-dimensional electron gas in a magnetic field

We present the results of a variational Monte Carlo calculation of the exchange-correlation energy for a spin-polarized two-dimensional electron gas in a perpendicular magnetic field. These energies are a necessary input to the recently developed current-density functional theory. Landau-level mixing is included in a variational manner, which gives the energy at finite density at finite field, in contrast to previous approaches. Results are presented for the exchange-correlation energy and excited-state gap at $\nu =$ 1/7, 1/5, 1/3, 1, and 2. We parameterize the results as a function of $r_s$ and $\nu$ in a form convenient for current-density functional calculations.Comment: 36 pages, including 6 postscript figure

Freezing of the quantum Hall liquid at ν=\nu = 1/7 and 1/9

We compare the free energy computed from the ground state energy and low-lying excitations of the 2-D Wigner solid and the fractional quantum Hall liquid, at magnetic filling factors $\nu = 1/7$ and 1/9. We find that the Wigner solid melts into the fractional quantum Hall liquid at roughly the same temperature as that of some recent luminescence experiments, while it remains a solid at the lower temperatures characteristic of the transport experiments. We propose this melting as a consistent interpretation of both sets of experiments.Comment: uses RevTeX 2.0 or 3.

HIV-Specific Cellular Immune Response Is Inversely Correlated with Disease Progression as Defined by Decline of CD4+ T Cells in Relation to HIV RNA Load

The average time between infection with human immunodeficiency virus (HIV) and development of acquired immune deficiency syndrome is ∼8 years. However, progression rates vary widely, depending on several determinants, including HIV-specific immunity, host genetic factors, and virulence of the infecting strain. In untreated HIV-infected patients with different progression rates, we examined HIV-specific T cell responses in combination with host genetic markers, such as chemokine/chemokine-receptor (CCR) polymorphisms and human leukocyte antigen (HLA) genotypes. HIV-specific CD4+ T cell responses and, to a lesser extent, HIVspecific CD8+ T cell responses were inversely correlated with progression rate. Slower progression was not related to polymorphisms in CCR genes, HLA genotype, or GB virus C coinfection. These data suggest that HIV-specific T cell responses are involved in protecting the host from disease progressio

Depicting community perspectives: repeat photography and participatory research as tools for assessing environmental services in Sagarmatha National Park, Nepal

Efforts have been made to provide a scientific basis for using environmental services as a conceptual tool to enhance conservation and improve livelihoods in protected mountain areas (MtPAS). Little attention has been paid to participatory research or locals’ concerns as environmental service (ES) users and providers. Such perspectives can illuminate the complex interplay between mountain ecosystems, environmental services and the determinants of human well-being. Repeat photography, long used in geographical fieldwork, is new as a qualitative research tool. This study uses a novel application of repeat photography as a diachronic photo-diary to examine local perceptions of change in ES in Sagarmatha National Park. Results show a consensus among locals on adverse changes to ES, particularly protection against natural hazards, such as landslides and floods, in the UNESCO World Heritage Site. We argue that our methodology could complement biophysical ecosystem assessments in MtPAS, especially since assessing ES, and acting on that, requires integrating diverse stakeholders’ knowledge, recognizing power imbalances and grappling with complex social-ecological systems

Addressing the psychology of weight loss and maintenance: a feasibility study of the Skills for weight loss and Maintenance weight management programme

Objectives: Building on prior theory, we aimed to evaluate the feasibility and acceptability of integrating novel, weight loss maintenance strategies into existing weight management programmes. We also piloted recruitment and data collection procedures for future research. Design: Two phases of action research nested within a single‐arm feasibility study. The intervention was refined between phases using feedback from intervention fidelity analysis and qualitative exploration of patient and provider experiences. Changes in outcomes were assessed up to 18 months post‐baseline. Methods: One hundred adults with a mean body mass index of 37 kg/m2 were offered the Skills for weight loss and Maintenance (SkiM) intervention. This included existing weight management programme content and additional weight loss maintenance techniques delivered fortnightly for 6 months in local community centres to groups of 11–15 people. Results: Of the 100 participants, 65%, 58% and 56% provided data at 7, 12 and 18 months. Across both phases, the mean initial weight loss was 4.2 kg (95% CI: 2.4–5.9) and 3.1 kg at 18 months (95% CI: .8–5.5). In Phase 2, we observed better weight loss maintenance (.5 kg [13.2%] regain from 7 to 18 months, vs. 1.7 kg [36.2%] in Phase 1). Variation in outcomes, high early dropout rates and qualitative feedback indicated that, although delivery of the intervention and trial procedures was feasible and acceptable, there was scope to refine the intervention to engage a wider range of participants. Intervention fidelity was acceptable, particularly in Phase 2. Conclusions: The SkiM intervention seems promising, but more research is needed to improve recruitment and retention prior to further evaluation