Who\u27s on Top? The Mental Health of Men Who Have Sex with Men

Despite most men who have sex with men (MSM) expressing intercourse position preference (e.g., “top”, “versatile”, or “bottom”), there is little information regarding sexual behavior and mental health sequelae. From the perspective of gender schema theory, the current study examined how position preference related to gender roles, internalized homophobia, and mental health. A total of 70 MSM (U.S. residents, M age = 28.89 years, 68.6% White) were recruited for an online study and grouped according to position preference. Groups were mostly similar across demographic variables, although bottoms had fewer sexual partners and lower condom use than tops and versatiles. In terms of gender roles, tops and versatiles were significantly higher in both masculine and feminine traits than bottoms. Tops were significantly more likely to report internalized homophobia than versatiles and bottoms. After controlling for masculinity, versatiles had the highest mental health. Results suggest further study of different sub-populations of MSM is warranted

Poly-essential and general Hyperelastic World (brane) models

This article provides a unified treatment of an extensive category of non-linear classical field models whereby the universe is represented (perhaps as a brane in a higher dimensional background) in terms of a structure of a mathematically convenient type describable as hyperelastic, for which a complete set of equations of motion is provided just by the energy-momentum conservation law. Particular cases include those of a perfect fluid in quintessential backgrounds of various kinds, as well as models of the elastic solid kind that has been proposed to account for cosmic acceleration. It is shown how an appropriately generalised Hadamard operator can be used to construct a symplectic structure that controles the evolution of small perturbations, and that provides a characteristic equation governing the propagation of weak discontinuities of diverse (extrinsic and extrinsic) kinds. The special case of a poly-essential model - the k-essential analogue of an ordinary polytropic fluid - is examined and shown to be well behaved (like the fluid) only if the pressure to density ratio $w$ is positive.Comment: 16 pages Latex, Contrib. to 10th Peyresq Pysics Meeting, June 2005: Micro and Macro Structures of Spacetim

Inter-laboratory comparison of fission track confined length and etch figure measurements in apatite

Apatite fission-track length and etch figure data are powerful tools for obtaining thermal history information, but both require human analysts making manual measurements and reproducibility is not assured. We report the results of an inter-laboratory study designed to clarify areas of congruence and divergence for these measurements and provide a basis for evaluating best practices to enhance intercompatibility of data sets. Four samples of megacrystic apatite from Durango, Mexico, with induced tracks, one unnannealed and three thermally annealed by varying amounts, were distributed internationally. In all, 55 analysts in 30 laboratory groups participated in the experiment. Relative mean track lengths among the samples were consistent across all analysts, but measurements for each sample showed scatter among labs and analysts considerably in excess of statistical expectation. Normalizing measurements of annealed samples using the unannealed sample improved consistency, as did normalizing for track angle using c-axis projection. Etch figure data also showed variability beyond statistical expectation, and consistency was improved by normalizing. Based on these data we recommend rigorous analyst training for length and etch figure measurement that includes measurement of standards, and that each analyst’s data on unknowns be normalized by that analyst’s own measurements on standards when using thermal history inverse modeling as part of the interpretation process

Gravitational Perturbations of Relativistic Membranes and Strings

We consider gravitationally induced perturbations of relativistic Dirac--Goto--Nambu membranes and strings (or {\it p}-branes). The dynamics are described by the first and second fundamental tensors, and related curvature tensors in an {\it n}-dimensional spacetime. We show how equations of motion can be derived for the perturbations within a general gauge and then discuss how various simple gauge choices can be used to simplify the equations of motion for specific applications. We also show how the same equations of motion can be derived from an effective action by a variational principle. Finally, we compare these equations of motion to those using more familiar notation for brane dynamics, which involves the induced metric on the worldsheet. This work sets up a general formalism for understanding the effects of backreaction on brane dynamics and the background curvature.Comment: 11 Pages, Plain TEX, to appear Phys. Lett.

On the gravitational, dilatonic and axionic radiative damping of cosmic strings

We study the radiation reaction on cosmic strings due to the emission of dilatonic, gravitational and axionic waves. After verifying the (on average) conservative nature of the time-symmetric self-interactions, we concentrate on the finite radiation damping force associated with the half-retarded minus half-advanced ``reactive'' fields. We revisit a recent proposal of using a ``local back reaction approximation'' for the reactive fields. Using dimensional continuation as convenient technical tool, we find, contrary to previous claims, that this proposal leads to antidamping in the case of the axionic field, and to zero (integrated) damping in the case of the gravitational field. One gets normal positive damping only in the case of the dilatonic field. We propose to use a suitably modified version of the local dilatonic radiation reaction as a substitute for the exact (non-local) gravitational radiation reaction. The incorporation of such a local approximation to gravitational radiation reaction should allow one to complete, in a computationally non-intensive way, string network simulations and to give better estimates of the amount and spectrum of gravitational radiation emitted by a cosmologically evolving network of massive strings.Comment: 48 pages, RevTex, epsfig, 1 figure; clarification of the domain of validity of the perturbative derivation of the string equations of motion, and of their renormalizabilit

The immunological response to intact and dissociated bluetongue virus in mice

Antigenic fractions of bluetongue virus were separated by ultracentrifugation in Tris-buffered CsCl gradients at pH 6, 7 or 8 and the bluetongue virus polypeptide composition of the bands isolated from these gradients was monitored by polyacrylamide gel slab electrophoresis. The immunological response to these fractions in mice was determined by a haemolytic plaque-forming cell assay, using sheep erythrocytes onto which intact bluetongue virus was adsorbed as lytic indicator cells. Isolated outer layer bluetongue virus polypeptide 2, from gradients at pH 6, and polypeptides 2 and 5, from gradients at pH 7, produced a strong primary JgM plaque-forming cell response. The subviral particles of density 1,39 g.cmֿ ֿֿֿ³ and the bluetongue virus core particles of density 1,42 g.cmֿ ֿ³ also stimulated an IgM response at least as strong as that to intact bluetongue virus of density 1,38 g.cmֿֿ ֿ³. The isolated bluetongue virus fractions therefore appear to maintain their immunogenic integrity as effectively as those of intact bluetongue virus. The pattern of the immune response to bluetongue virus type 4 is similar to that of type 10The articles have been scanned in colour with a HP Scanjet 5590; 300dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

Sheep erythrocyte and bluetongue virus antibody responses of spleen cell cultures from mice

The optimum conditions for the culture of cells from dissociated spleens were determined. Routinely, 10⁷ cells were seeded per ml of RPMI 1640 medium supplemented with 20% pre-tested foetal calf serum. For the assay of the immune response, cultures were supplemented with 30 µMolar mercaptoethanol. The immune responses to sheep erythrocyte and bluetongue virus antigens were determined by the haemolytic plaque-forming cell assays described by Oellermann (1974) and Oellermann, Carter & Marx (1976a). The optimum sheep erythrocyte antigen concentration was 2 x 10⁶ erythrocytes per 10⁷ spleen cells and maximum IgM plaque-forming cells were detected after 4 days in culture. Successful stimulation of the immune response to bluetongue virus was achieved in spleen cell cultures from mice previously primed with bluetongue virus. The optimum antigen concentration was 30-40 ng bluetongue virus per 10⁷ spleen cells and the maximum plaque-forming cell response was observed after 4 days in culture.The articles have been scanned in colour with a HP Scanjet 5590; 300dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

Irrigation of Crops: Drainage Water Quality

Recent research has provided new knowledge on managing irrigation water to decrease the degrading effects of irrigation on the mineral quality of drainage water and to increase crop yield and quality by effective use of sprinkler irrigation. In sprinkler irrigation, water is exposed to the atmosphere, which enhances evaporation. The evaporation process cools the droplets, increases the heat absorbed by the droplets from the air through which they pass, and adds water vapor to the atmosphere. It has also been determined that the plant as well as its environment can he cooled with water applied by sprinklers

Kinetics of the IgM and IgG immunological response to sheep erythrocytes and bluetongue virus in mice

The IgM and IgG response of mice to sheep erythrocytes (SRBC) and bluetongue virus (BTV) was determined by means of haemolytic plaque assays. Maximum primary IgM response to SRBC occurred after 4 days but declined rapidly to 4% of the maximum by Day 9. A lag period of about 2 days was observed in the appearance of IgG haemolytic plaque-forming cells (PFC) but they reached a maximum after 6-9 days. Secondary immunization resulted in the stimulation particularly of IgG PFC and from Day 6 onwards IgG predominated in the immunological response. The IgM response to BTV was remarkably similar to that observed when SRBC were used as antigen. IgG PFC, however, appeared within a day of the IgM, reaching a peak on Days 4-5. From then onwards, IgG PFC predominated in the response. At BTV concentrations of up to 10 µg per mouse, the virulent strain of BTV type 3 produced the weakest response. At higher antigen concentrations there was very little difference in the response to the serotypes tested, although the virulent strain of BTV type 4 tended to produce the strongest response.The articles have been scanned in colour with a HP scanjet 5590; 300dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to final presentyation PDF-Format

Phagocytic activity of peritoneal exudate cells from mice

Phagocytic activity of peritoneal exudate cells in mice was stimulated by injection of 0,1 ml mineral oil or varying concentrations of lysolecithin. Optimal lysolecithin concentration was found to be 2 to 5 µg per mouse. The phagocytic activity of peritoneal exudate cells from mice was determined by spectral analysis of dioxane extracts of cells after incubation in the presence of polystyrene latex particles. Maximum uptake of latex particles occurred after an incubation period of 1 h. Maximum phagocytic activity was observed in cells harvested 3 days after stimulation with mineral oil and approximately 4 days after stimulation with lysolecithin. Electron microscopy of these cells revealed a similar pattern of phagocytic activity. Latex particles are inert and not metabolized by the cells and their uptake was therefore compared with the phagocytosis of bluetongue virus particles. Electron microscopic studies of the uptake of bluetongue virus showed that although adsorption of the virus on the surface membrane occurred practically no phagocytosis was observed 1 day after stimulation with lysolecithin. Maximum phagocytosis of virus particles occurred 3 to 4 days after stimulation with lysolecithin.The articles have been scanned in colour with a HP Scanjet 5590;300dpi. adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format