Is bigger better? The relationship between size and reproduction in female Asian elephants.

The limited availability of resources is predicted to impose trade-offs between growth, reproduction and self-maintenance in animals. However, although some studies have shown that early reproduction suppresses growth, reproduction positively correlates with size in others. We use detailed records from a large population of semi-captive elephants in Myanmar to assess the relationships between size (height and weight), reproduction and survival in female Asian elephants, a species characterized by slow, costly life history. Although female height gain during the growth period overlapped little with reproductive onset in the population, there was large variation in age at first reproduction and only 81% of final weight had been reached by peak age of reproduction at the population level (19 years). Those females beginning reproduction early tended to be taller and lighter later in life, although these trends were not significant. We found that taller females were more likely to have reproduced by a given age, but such effects diminished with age, suggesting there may be a size threshold to reproduction which is especially important in young females. Because size was not linked with female survival during reproductive ages, the diminishing effect of height on reproduction with age is unlikely to be due to biased survival of larger females. We conclude that although reproduction may not always impose significant costs on growth, height may be a limiting factor to reproduction in young female Asian elephants, which could have important implications considering their birth rates are low and peak reproduction is young - 19 years in this population.

Is the History of Substance Abuse Correlated with Neuropsychiatric Disorders and Co-morbid HIV Infection? An Urban Population Study.

BACKGROUND: Human immunodeficiency virus (HIV) infection remains a serious immunological disease with new infections in the U.S. disproportionately reported in minority populations. For many years, the District of Columbia (DC) has reported the highest HIV infection rate in the nation. Drug abuse and addiction is also prevalent in DC and has traditionally been linked to HIV/AIDS because of the likelihood for opportunistic infections. Despite this data, the relationship between HIV status, drugs of abuse, and the incidence of neurological disorders are scarcely reported for minority populations. METHOD: We carried out a retrospective study on the prevalence of substance abuse in HIV and their association with neuropsychiatric comorbidities in an African American subpopulation in Washington DC. FINDINGS: Our data suggests an 86 percent prevalence of drug use in the HIV patients with neuropsychiatric comorbidities, with cocaine use being significantly higher in patients with major depressive disorder (MDD) and bipolar disorder (BD), whereas PCP use was associated with patients with schizophrenia. The mean CD4 count was elevated in patients with neuropsychiatric disease, and specifically in MDD patients. CD8 counts were elevated as expected for HIV status but were not influenced by disease diagnosis. A majority (2/3) of patients were on HAART therapy, however the records did not account for adherence. CONCLUSION: These data suggest that neuropsychiatric comorbidities are independent of HIV disease progression but are correlated with certain illicit drugs of abuse.

Adapting just-in-time inventory control to the hospital setting.

The principles of Just-in-Time inventory management are essentially those of sensible management of productivity and waste. Much of the literature written about JIT, however, is limited in scope in that it focuses on applications in a manufacturing operation. The best way to assess JIT's applicability to all businesses, including hospitals, is to synthesize the characteristics into a basic, conceptual model, which the author does in the following article.

Plasmodesmal targeting and intercellular movement of potato mop-top pomovirus is mediated by a membrane anchored tyrosine-based motif on the lumenal side of the endoplasmic reticulum and the C-terminal transmembrane domain in the TGB3 movement protein.

Live-cell fluorescence microscopy was used to investigate the third triple gene block protein (TGB3) of potato mop-top pomovirus and its role in assisted targeting of TGB2 to plasmodesmata (PD). Wild-type and mutant TGB3 proteins were expressed under the control of the 35S promoter or from a virus reporter clone. Assisted targeting of TGB2 to PD was optimal when the proteins were expressed from a bicistronic plasmid in the relative ratios expected in a virus infection, suggesting that excess TGB3 inhibited PD localisation. Contrary to the generally accepted view, bimolecular fluorescence complementation showed that the TGB3 N terminus is located in the cytosol. Mutational analysis to dissect TGB3 sub domain functions showed that PD targeting was mediated by a composite signal comprising an ER-lumenal tyrosine-based motif and the C-terminal transmembrane domain. Mutation of either of these domains also abolished cell-to-cell movement of the virus. The results are discussed in the context of TGB3 membrane topology.

Demand/capacity management in health care: an application of yield management.

Although the concepts of yield management have been applied successfully to many services such as hotels and airlines, the concepts have not expanded much further. Some segments of health care appear to be logical candidates to apply and benefit from the concepts, and this article addresses that application by examining the implementation of yield management in a health care facility. Not only is the implementation described, but the issues surrounding that implementation are discussed.

Mapping of the Tobacco mosaic virus movement protein and coat protein subgenomic RNA promoters in vivo.

The Tobacco mosaic virus movement protein (MP) and coat protein (CP) are expressed from 3'-coterminal subgenomic RNAs (sgRNAs). The transcription start site of the MP sgRNA, previously mapped to positions 4838 (Y. Watanabe, T. Meshi, and Y. Okada (1984), FEBS Lett. 173, 247-250) and 4828 (K. Lehto, G. L. Grantham, and W. O. Dawson (1990), Virology 174, 145-157) for the TMV OM and U1 strains, respectively, has been reexamined and mapped to position 4838 for strain U1. Sequences of the MP and CP sgRNA promoters were delineated by deletion analysis. The boundaries for minimal and full MP sgRNA promoter activity were localized between -35 and +10 and -95 and +40, respectively, relative to the transcription start site. The minimal CP sgRNA promoter was mapped between -69 and +12, whereas the boundaries of the fully active promoter were between -157 and +54. Computer analysis predicted two stem-loop structures (SL1 and SL2) upstream of the MP sgRNA transcription start site. Deletion analysis and site-directed mutagenesis suggested that SL1 secondary structure, but not its sequence, was required for MP sgRNA promoter activity, whereas a 39-nt deletion removing most of the SL2 region increased MP sgRNA accumulation fourfold. Computer-predicted folding of the fully active CP sgRNA promoter revealed one long stem-loop structure. Deletion analysis suggested that the upper part of this stem-loop, located upstream of the transcription start site, was essential for transcription and that the lower part of the stem had an enhancing role.