The Partner Study: Sexual Risks

poster abstractThe Partner Study is a five-year, NIH-Funded research project focused on the potential sexual transmission of HIV from those with the disease to their partners without the disease and on to other sex partners. The project interviewed 114 people with HIV (HIV+), 114 of their sex partners without HIV (HIV-), and also 146 HIV- persons without an HIV+ partner. The project focuses on the reasons why people protect themselves and others. It thus examines such factors as knowledge of HIV, concern about getting or giving the disease, the impact of social norms, partners’ disclosure of HIV status, and ability to communicate with one’s sex partner(s). The findings to be presented include: • A test of the AIDS Risk Reduction Model that is designed to identify the critical factors that determine the activation of a person’s self protection motivation. • An examination of the relevance of social norms to HIV-protection behaviors. Though social scientists have relied on social norms as explanations for behavior since Durkheim, in these findings (1) social norms appear to have a modest effect on behavior even in areas where norms of protection had been thought to be strong and (2) enforcement of social norms is unrelated to eventual behavior. • An examination of multiple reasons people give for using or not using condoms and what those reasons say about their motivations and actual condom use. • An examination of how privacy rules regulate the disclosure of information about HIV to sex partners. Using the Communication Privacy Management perspective (Petronio, 2002), this study examines the privacy boundary surrounding information about HIV status by both the HIV+ partner and the HIV- partner

Final Report: Lake Vostok: A Curiosity or a Focus for Interdisciplinary Study?

The goal of the NSF-sponsored workshop, held in held in Washington, D.C., on November 7-8, 1998, was to stimulate discussion within the U.S. science community on Lake Vostok, specifically addressing the question: "Is Lake Vostok a natural curiosity or an opportunity for uniquely posed interdisciplinary scientific programs?" The workshop was designed to outline an interdisciplinary science plan for studies of the lake

Evolutionary Processes a Focus of Decade-Long Ecosystem Study of Antarctic's Lake Vostok

As scientists probe for life in new habitats and try to understand the processes that triggered the origin and guided the evolution of life on Earth, environments beneath large ice sheets are beginning to emerge as key ecosystems. Modern subglacial environments are analogues both for the icy moons of Jupiter and the environmental stresses that led to widespread evolutionary radiation following the Neoproterozoic "snowball" Earth. The largest modern analogue to these distant systems is Lake Vostok, a great Antarctic subglacial lake, and the international science community is developing a plan to systematically survey and explore this complex system over the next decade. Approximately the size of Lake Ontario, Lake Vostok lies beneath the 4 km thick East Antarctic ice sheet (Figure 1). The lake is much deeper than Lake Ontario—remotely measured water depths reach 670 m

Assumptions for a Market Share Theorem

Many marketing models use variants of the relationship: market share equals marketing effort divided by total marketing effort. Usually, share is defined within a customer group presumed to be reasonably homogeneous and overall share is obtained by weighting for the number in the group. Although the basic relationship can be assumed directly, certain insight is gained by deriving it from more fundamental assumptions as follows: For the given customer group, each competitive seller has a real-valued "attraction" with the following properties: (1) attraction is non-negative; (2) the attraction of a set of sellers is the sum of the attractions of the individual sellers; and (3) if the attractions of two sets of sellers are equal, the sellers have equal market shares in the customer groups. It is shown that, if the relation between share and attraction satisfies the above assumptions, is a continuous function, and is required to hold for arbitrary values of attraction and sets of sellers, then the relation is: Share equals attraction divided by total attraction. Insofar as various factors can be assembled into an attraction function that satisfies the assumptions of the theorem, the method for calculating share follows directly

Species Interactions Weakly Modify Climate-Induced Tree Co-Occurrence Patterns

Aims: Species distributions are hypothesized to be underlain by a complex association of processes that span multiple spatial scales including biotic interactions, dispersal limitation, fine-scale resource gradients and climate. Species disequilibrium with climate may reflect the effects of non-climatic processes on species distributions, yet distribution models have rarely directly considered non-climatic processes. Here, we use a Joint Species Distribution Model (JSDM) to investigate the influence of non-climatic factors on species co-occurrence patterns and to directly quantify the relative influences of climate and alternative processes that may generate correlated responses in species distributions, such as species interactions, on tree co-occurrence patterns. Location: US Rocky Mountains. Methods: We apply a Bayesian JSDM to simultaneously model the co-occurrence patterns of ten dominant tree species across the Rocky Mountains, and evaluate climatic and residual correlations from the fitted model to determine the relative contribution of each component to observed co-occurrence patterns. We also evaluate predictions generated from the fitted model relative to a single-species modelling approach. Results: For most species, correlation due to climate covariates exceeded residual correlation, indicating an overriding influence of broad-scale climate on co-occurrence patterns. Accounting for covariance among species did not significantly improve predictions relative to a single-species approach, providing limited evidence for a strong independent influence of species interactions on distribution patterns. Conclusions: Overall, our findings indicate that climate is an important driver of regional biodiversity patterns and that interactions between dominant tree species contribute little to explain species co-occurrence patterns among Rocky Mountain trees

The Indo-U.S. Library of Coude Feed Stellar Spectra

We have obtained spectra for 1273 stars using the 0.9m Coud\'e Feed telescope at Kitt Peak National Observatory. This telescope feeds the coud\'e spectrograph of the 2.1m telescope. The spectra have been obtained with the #5 camera of the coud\'e spectrograph and a Loral 3K X 1K CCD. Two gratings have been used to provide spectral coverage from 3460 \AA to 9464 \AA, at a resolution of $\sim$1\AA FWHM and at an original dispersion of 0.44 \AA/pixel. For 885 stars we have complete spectra over the entire 3460 \AA to 9464 \AA wavelength region (neglecting small gaps of $<$ 50 \AA), and partial spectral coverage for the remaining stars. The 1273 stars have been selected to provide broad coverage of the atmospheric parameters T$_{eff}$, log g, and [Fe/H], as well as spectral type. The goal of the project is to provide a comprehensive library of stellar spectra for use in the automated classification of stellar and galaxy spectra and in galaxy population synthesis. In this paper we discuss the characteristics of the spectral library, viz., details of the observations, data reduction procedures, and selection of stars. We also present a few illustrations of the quality and information available in the spectra. The first version of the complete spectral library is now publicly available from the National Optical Astronomy Observatory (NOAO) via FTP and HTTP.Comment: 18 pages, 6 figures, 4 table

Consumer Shopping Behaviors and In-Store Expenditure Decisions

The authors study the effect that consumers’ adopted shopping patterns have on their responsiveness to pricing activity of retailers. Two important dimensions of shopping behavior — inclination to switch stores and preference for a particular retail price format (every day low price (EDLP) or promotional price (HILO)) are hypothesized to systematically affect the responsiveness of in-store expenditure decisions to changes in prices. In particular, store loyal households should be more responsive to changes in prices when deciding how much to buy in a given store. Similarly, the household shopping in a HILO format (where price variability is greater) should be more responsive. These hypotheses are developed and then tested using a joint model of store choice and in-store expenditure which accounts for potential interdependence between these decisions. The findings attest to the ability of consumers to exploit variation in the environment: When constrained on one dimension (e.g., by shopping in only one store), consumers exhibit flexibility on another (e.g., by adjusting expenditures in response to price changes). If afforded the opportunity to be flexible (e.g., through variable prices at a HILO store), consumers take advantage of this. These aspects of shopping behavior interact in a theoretically interesting, but counter-intuitive way: the expenditure decisions of HILO switching consumers turn out to be the least responsive to changes in prices at a particular store. These shoppers exploit advertised price differences and move among stores. This responsiveness in the store choice decision means they have less incentive to exhibit flexibility in their expenditure decisions at a given store. The authors present estimates from a series of models calibrated on a scanner panel data set which captures store choices and expenditure receipts, and find all hypotheses to be supported