Whereas some people appear to cope after learning that they have human immunodeficiency virus (HIV) infection, others experience depression and suicidal ideation. In this study, 142 persons with HIV infection were administered the Center for Epidemiological Studies Depression Scale (CES-D). High levels of depression were predicted by lower perceived social support, attributions that health was influenced more by chance, high-risk sexual behavior practices, and greater number of HIV illness symptoms and greater duration of time knowing of one's own positive serostatus. Ongoing high-risk sexual behavior practices were predicted by higher levels of recreational drug use and of depression. These findings highlight the need for improved mental health services for persons with HIV conditions.

The use of potential vorticity (PV) allows the efficient description of the dynamics of nearly balanced atmospheric flow phenomena, but the distribution of PV must be simply represented for ease in interpretation. Representations of PV on isentropic or isobaric surfaces can be cumbersome, as analyses of several surfaces spanning the troposphere must be constructed to fully apprehend the complete PV distribution.Following a brief review of the relationship between PV and nearly balanced flows, it is demonstrated that the tropospheric PV has a simple distribution, and as a consequence, an analysis of potential temperature along the dynamic tropopause (here defined as a surface of constant PV) allows for a simple representation of the upper-tropospheric and lower-stratospheric PV. The construction and interpretation of these tropopause maps, which may be termed ''isertelic'' analyses of potential temperature, are described. In addition, techniques to construct dynamical representations of the lower-tropospheric PV and near-surface potential temperature, which complement these isertelic analyses, are also suggested. Case studies are presented to illustrate the utility of these techniques in diagnosing phenomena such as cyclogenesis, tropopause folds, the formation of an upper trough, and the effects of latent heat release on the upper and lower troposphere.

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In this study, the impacts of regions of weak inertial stability on tropical cyclone intensification and peak strength are examined. It is demonstrated that weak inertial stability in the outflow layer minimizes an energy sink of the tropical cyclone secondary circulation and leads to more rapid intensification to the maximum potential intensity. Using a full-physics, three-dimensional numerical weather prediction model, a symmetric distribution of environmental inertial stability is generated using a variable Coriolis parameter. It is found that the lower the value of the Coriolis parameter, the more rapid the strengthening. The lower-latitude simulation is shown to have a significantly stronger secondary circulation with intense divergent outflow against a comparatively weak environmental resistance. However, the impacts of differences in the gradient wind balance between the different latitudes on the core structure cannot be neglected. A second study is then conducted using an asymmetric inertial stability distribution generated by the presence of a jet stream to the north of the tropical cyclone. The initial intensification is similar, or even perhaps slower, in the presence of the jet as a result of increased vertical wind shear. As the system evolves, convective outflow from the tropical cyclone modifies the jet resulting in weaker shear and more rapid intensification of the tropical cyclone–jet couplet. It is argued that the generation of an outflow channel as the tropical cyclone outflow expands into the region of weak inertial stability on the anticyclonic shear side of the jet stream minimizes the energy expenditure of forced subsidence by ventilating all outflow in one long narrow path, allowing radiational cooling to lessen the work of subsidence. Furthermore, it is hypothesized that evolving conditions in the outflow layer modulate the tropical cyclone core structure in such a way that tropical cyclone outflow can access weak inertial stability in the environment.

In vitro and in silico studies of the CaaX-type prenyl transferases suggest a wider array of prenylatable sequences than those determined in vivo. Berger and Kim et al. investigate whether this disconnect is due to use of...