Miami University

About: Miami University is a education organization based out in Oxford, Ohio, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 9949 authors who have published 19598 publications receiving 568410 citations. The organization is also known as: Miami of Ohio & Miami-Ohio.

Gene expression changes governing extreme dehydration tolerance in an Antarctic insect

Abstract: Among terrestrial organisms, arthropods are especially susceptible to dehydration, given their small body size and high surface area to volume ratio. This challenge is particularly acute for polar arthropods that face near-constant desiccating conditions, as water is frozen and thus unavailable for much of the year. The molecular mechanisms that govern extreme dehydration tolerance in insects remain largely undefined. In this study, we used RNA sequencing to quantify transcriptional mechanisms of extreme dehydration tolerance in the Antarctic midge, Belgica antarctica, the world's southernmost insect and only insect endemic to Antarctica. Larvae of B. antarctica are remarkably tolerant of dehydration, surviving losses up to 70% of their body water. Gene expression changes in response to dehydration indicated up-regulation of cellular recycling pathways including the ubiquitin-mediated proteasome and autophagy, with concurrent down-regulation of genes involved in general metabolism and ATP production. Metabolomics results revealed shifts in metabolite pools that correlated closely with changes in gene expression, indicating that coordinated changes in gene expression and metabolism are a critical component of the dehydration response. Finally, using comparative genomics, we compared our gene expression results with a transcriptomic dataset for the Arctic collembolan, Megaphorura arctica. Although B. antarctica and M. arctica are adapted to similar environments, our analysis indicated very little overlap in expression profiles between these two arthropods. Whereas several orthologous genes showed similar expression patterns, transcriptional changes were largely species specific, indicating these polar arthropods have developed distinct transcriptional mechanisms to cope with similar desiccating conditions.

An investigation of session impact and alliance in internet based psychotherapy: Preliminary results

Abstract: Although psychotherapy has been and continues to be a face-to-face activity primarily, a growing minority of therapists are conducting text-based (i.e. e-mail) psychotherapy over the Internet. This study compared the session impact (measured by the Session Evaluation Questionnaire, SEQ; Stiles, Gordon, & Lani, 2002) and the client-therapist alliance (measured by the Agnew Relationship Measure, ARM; Agnew-Davies, Stiles, Hardy, Barkham, & Shapiro, 1998) of the exchanges between clients and therapists who are engaged in e-mail therapy with previously published results on face-to-face therapy. According to preliminary results, the online clients provided similar session impact and therapeutic alliance ratings compared to face-to-face clients. Although online therapists followed this general trend, they evaluated the depth, smoothness, and positivity aspects of session impact and confidence aspect of therapeutic alliance more highly than face-to-face therapists.

Effects of available P and N:P ratios on non-symbiotic dinitrogen fixation in tallgrass prairie soils

Abstract: Prescribed burning is a major control over element cycles in Tallgrass prairie (Eastern Kansas, USA) In this paper we report potential effects of fire on nonsymbiotic nitrogen fixation Fire resulted in additions of available P in ash, which may stimulate nitrogen fixation by terrestrial cyanobacteria Cyanobacterial nitrogenase activity and biomass responded positively to additions of ash or P in laboratory assays using soil Further assays in soil showed that cyanobacteria responded to changes in available N:available P ratio (aN:P) across a range of concentrations Nitrogen fixation rate could be related empirically to aN:P via a log-linear relationship Extrapolation of laboratory results to the field yielded a maximal estimate of 21 kg N ha-1 y-1 Results support arguments from the marine and terrestrial literature that P availability is central to regulation of ecosystem N budgets

Mating behaviour, life history and adaptation to insecticides determine species exclusion between whiteflies.

Abstract: Summary 1. Negative interspecific interactions, such as resource competition or reproductive interference, can lead to the displacement of species (species exclusion). 2. Here, we investigated the effect of life history, mating behaviour and adaptation to insecticides on species exclusion between cryptic whitefly species that make up the Bemisia tabaci species complex. We conducted population cage experiments independently in China, Australia, the United States and Israel to observe patterns of species exclusion between an invasive species commonly referred to as the B biotype and three other species commonly known as biotypes ZHJ1, AN and Q. 3. Although experimental conditions and species varied between regions, we were able to predict the observed patterns of exclusion in each region using a stochastic model that incorporated data on development time, mating behaviour and resistance to insecticides. 4. Between-species variation in mating behaviour was a more significant factor affecting species exclusion than variation in development time. Specifically, the ability of B to copulate more effectively than other species resulted in a faster rate of population increase for B, as well as a reduced rate of population growth for other species, leading to species exclusion. The greater ability of B to evolve resistance to insecticides also contributed to exclusion of other species in some cases. 5. Results indicate that an integrative analysis of the consequences of variation in life-history traits, mating behaviours and adaption to insecticides could provide a robust framework for predicting species exclusion following whitefly invasions.

Evaluating Government Bond Fund Performance with Stochastic Discount Factors

Abstract: This paper evaluates the performance of government bond mutual funds with stochastic discount factors from continuous-time term structure models. The approach addresses the interim trading bias described by Goetzmann, Ingersoll and Ivkovic (2000) and Ferson and Khang (2002). It replaces the ad hoc selection of empirical factors and instruments with variables prescribed by theory. Time-aggregation of the models for discrete returns generates empirical factors that contribute explanatory power to the models, and may be useful in other settings. We provide the first conditional performance evaluation for US fixed income mutual funds. During 1986-2000 most government bond funds returned less on average than passive benchmarks that don't pay expenses, but not for all states of the term structure. The abnormal returns are reduced, and with a few interesting exceptions become insignificant, when we adjust for risk using the stochastic discount factors from term structure models.