The prototype Alphavirus, Sindbis virus (SIN), relies on cyclic transmission between the mosquito and vertebrate hosts in order to be maintained in nature. This broad host range suggests that alphaviruses use a universally expressed molecule for attachment. Heparan sulfate proteoglycan (HSPG), a ubiquitous SIN receptor present on the cell surface of most eukaryotic cells, has been reported in the salivary glands and midguts of mosquitoes. These organs are essential for virus transmission from this hematophageous invertebrate. Variable host cell response in the mosquito following intrathoracic inoculation with SIN has been documented. In this study, per os infection of Aedine species with variants of SIN was used to determine organ specific responses to virus as well as the temporal kinetics of SIN dissemination via leg assay. Analysis indicated AR339 virus dissemination in samples at day 14 days post infection (p.i.). TR339 was identified at day 12 in legs of virus fed individuals. AR339, the HSPG adapted variant resulted in SIN-associated pathology in salivary glands of Aedes albopictus. This pathology was limited to lateral lobes, while the median lobe remained unaffected. Infection with TR339, a HSPG-independent variant, did not result in virus-associated pathology in the salivary gland to day 28 post infection. Immunohistochemistry determined that HSPG was located in the lateral lobe duct region of the salivary glands. It has been suggested that human lactoferrin (hLF) may interfere with virus receptor attachment and is involved in inhibition of virus infection in vertebrate cells. To that end, the effects of bovine LF inhibition on virus attachment were compared between AR339 and TR339 in the mosquito cell line C7-10. Cytopathic effect was observed earlier and with greater intensity in TR339 infected monolayers when compared to AR339 infected monolayers. This suggests that bovine LF has an inhibitory effect on AR339 infection in invertebrate cells, possibly due to this variants use of HPSG for attachment.

This investigation explored gender differences and relations among facets of adult stress measured by self-reported cognitive, emotional, and continuous psychophysiological responses to child and non-child stressors. The 46 male and 47 female participants displayed increased heart rate (HR) while watching a video of a happy infant and a decreased HR (associated with increased attentiveness) during a crying infant video. During a cold pressor task, males' HR increased while females revealed a contrary decline in HR. No differences between hyperactive and non-hyperreactive participants were found regarding hypothetical parenting plans or self-reported emotionality. Findings suggest more gender similarity than dissimilarity, possibly due to the evolving nature of parenting (i.e., males and females sharing increasingly analogous parenting roles).

Hepatitis B virus (HBV) is one of many viruses transmitted through the blood or body fluids. This paper concentrates on a mathematical study of the survival rate of HBV. Using data which includes the survival time for individuals who were diagnosed as being affected by HBV and those who died from HBV, we fit non-linear models to study the survival time for people affected by the virus. Survival probabilities suggest an exponential curve for the survival time. We also consider a pure death process which is a stochastic model for the survival time of the individuals affected. Our results show that individuals who have been diagnosed as having HBV have an estimated life expectancy of approximately 625 days.

Many methods have been developed to determine the "appropriate" subset of independent variables in a multiple variable problem. Some of the methods are application specific while others have a wide range of uses. This study compares two such methods, Regression Trees and Stepwise Regression. A simulation using a known distribution is used for the comparison. In 699 out of 742 cases the Regression Tree method gave better predictors than the Stepwise Regression procedure.

Identifying non-tracking individuals in a population of longitudinal data has many applications as well as complications. The analysis of longitudinal data is a special study in itself. There are several accepted methods, of those we chose a two-stage random effects model coupled with the Estimation Maximization Algorithm (E-M Algorithm) . Our project consisted of first estimating population parameters using the previously mentioned methods. The Mahalanobis distance was then used to sequentially identify and eliminate non-trackers from the population. Computer simulations were run in order to measure the algorithm's effectiveness. Our results show that the average specificity for the repetitions for each simulation remained at the 99% level. The sensitivity was best when only a single non-tracker was present with a very different parameter a. The sensitivity of the program decreased when more than one tracker was present, indicating our method of identifying a non-tracker is not effective when the estimates of the population parameters are contaminated.

Isolated populations that inhabit various geographic and climatic ranges tend to diverge in their life history tactics. When development time is constrained by unfavorable seasons, often an organism must trade-off the investment of resource allocation between somatic and reproductive growth. The variation in reproductive tactics and juvenile hormone titers were studied among three populations of Romalea microptera from Athens, GA, Jacksonville, FL, and Miami, FL, all of which exist on a latitudinal cline. The Athens population was significantly younger at oviposition and gained significantly less body mass than both the Jacksonville and Miami populations, which did not differ from each other. Clutch mass did not differ across populations. With respect to both body size and oviposition age, Athens invested significantly more (measured by clutch size) to their first clutch than either Jacksonville or Miami, which did not differ from each other. Juvenile hormone and lipid profiles did not differ among populations. In response to the markedly reduced season length, results suggest that Athens grasshoppers respond with reproductive tactics that support terminal investment by investing more energy in less time to reproduction, at the expense of future reproduction.

Research indicates that classroom behaviors in students may be good predictors of academic success. The present study investigated the relationship between classroom peers, positive and negative classroom behaviors, early literacy and mathematics ability, and classroom model in 214 predominately low-income preschool children in 21 classes across a six-county area. It was hypothesized that peer classroom behavior would be a significant predictor of individual child ability and that peers would have differential influence across classroom models. Results indicated that peer classroom behavior was not a significant predictor of individual child ability. Individual child classroom behaviors, specifically positive behaviors, emerged as a significant predictor of child ability. Peer ability and peer positive classroom behaviors emerged as significant predictors of individual child ability in classrooms that were structured with an academically directed model, but not in classrooms that were more structured with a combination of academic and child-centered models.

A method is described for finding the least squares solution of the overdetermined linear system that arises in the photogrammetric problem of bundle adjustment of aerial photographs. Because of the sparse, blocked structure of the coefficient matrix of the linear system, the proposed method is based on sparse QR factorization using Givens rotations. A reordering of the rows and columns of the matrix greatly reduces the fill-in during the factorization. Rules which predict the fill-in for this ordering are proven based upon the block structure of the matrix. These rules eliminate the need for the usual symbolic factorization in most cases. A subroutine library that implements the proposed method is listed. Timings and populations of a range of test problems are given.

Because a child's first day of school can be anxiety provoking, familiar soothing inanimate objects, such as blankets, might help to minimize discomfort related to this novel situation. The current study examined the anxiety level of twenty-six one- to four-year-old children and their mothers at three times 1) before the first day of school, 2) during separation from their mother on the first day of school, and 3) after home from their first day of school. Maternal report was used to assess child and mother anxiety levels (Likert scale 0- 10) and child level of attachment to a familiar inanimate object. No differences in anxiety levels were found among attached children who brought their attachment object with them on their first day of school, attached children without their objects, and unattached children with or without a familiar object. Children's anxiety did differ among the assessment times, verifying that separation from their mothers on first day of school is a low arousal situation. Mother's anxiety was not positively related to children's anxiety. Future studies might further explore an observed trend of children attached to inanimate objects displaying less anxiety than their unattached counterparts across school-related transitions.

Non-pathological sleep parameters in relation to cognition among individuals who do not qualify as having sleep disorders or who are not subjected to extended periods of total sleep deprivation have not been adequately investigated in previous studies. The current study investigates the influence of circadian typology (morning-type vs. evening-type individuals), time of session (AM vs. PM), habitual sleep practices (sleep hygiene), sleep quality, life stress, and the presence of an acute stressor on sustained attention, memory, and mental rotation performance. Several main effects emerged for individual variables above; however, the data failed to reveal significant interactions among these variables. The evidence in this study of non-pathological sleep parameters affecting cognitive performance presents a need for further investigation.