A Stochastic Compartmental Model for Fast Axonal Transport

In this paper we develop a probabilistic micro-scale compartmental model and use it to study macro-scale properties of axonal transport, the process by which intracellular cargo is moved in the axons of neurons. By directly modeling the smallest scale interactions, we can use recent microscopic experimental observations to infer all the parameters of the model. Then, using techniques from probability theory, we compute asymptotic limits of the stochastic behavior of individual motor-cargo complexes, while also characterizing both equilibrium and non-equilibrium ensemble behavior. We use these results in order to investigate three important biological questions: (1) How homogeneous are axons at stochastic equilibrium? (2) How quickly can axons return to stochastic equilibrium after large local perturbations? (3) How is our understanding of delivery time to a depleted target region changed by taking the whole cell point-of-view

Audit Committee Effectiveness: A Synthesis of the Empirical Audit Committee Literature

The article describes the factors that contribute to audit committee effectiveness. An effective audit committee has qualified members with the authority and resources to protect stakeholder interests by ensuring reliable financial reporting, internal controls, and risk management through its diligent oversight efforts. The determinants of audit committee effectiveness includes the audit committee composition, authority, resources and diligence. The major U.S. stock exchanges require that audit committees be composed of at least three independent, financially literate directors. Team issues also are relevant when considering audit committee composition. The audit committee derives its authority from the full board of directors, federal law and exchange listing requirements. Authority is viewed as a function of the audit committees responsibilities and influence. Audit committee authority also depends on the audit committees relationships with management, external and internal auditors and the board as a whole. The resource component of audit committee effectiveness highlights that effective oversight is contingent upon the audit committee having adequate resources to do its job. Diligence is the process factor that is needed to achieve audit committee effectiveness

Evaluation of a Group Administered 24-Hour Recall Method for Dietary Assessment

A group administered 24-hour food recall was developed by the Expanded Food and Nutrition Education Program of Texas to expedite dietary assessment of clients. The study reported here evaluated the group recall and an individual recall method. Data for one meal collected with the use of dietary recalls, either group of individual, were compared to observational data. Results suggest that the group recall may be at least as effective as the individual recall to estimate dietary intakes of subjects. The group recall method could be used by programs such as EFNEP to simplify and expedite dietary assessment of clients

Community Engagement with Older Adults to Evaluate Interprofessional Education in Allied Healthcare Students

Purpose: To examine students’ perceptions of interprofessional education (IPE) as a result of their participation in a community engagement experience with older adults. Methods: Thirty-six students enrolled in the undergraduate majors of athletic training, exercise science, and nutrition participated in an 8-week fall prevention program in two community dwelling senior centers. A one-group pretest-posttest evaluation design was used to assess the IPE experience of the students. Students completed the University of the West England Interprofessional Questionnaire pre and post intervention. Results: Both pretest and posttest student self-assessments of communication and teamwork skills ranged from slightly positive to neutral (means from 2.0 to 2.6). Students reported a statistical change in attitude from neutral (M = 2.3, SD + 1.1) in the direction of slightly positive (M = 2.0, SD + 1.1) toward being able to become quickly involved in new teams/groups from pretest to posttest t (26) = 2.53, p = .018; d = 0.49. 95% of students strongly agreed or agreed that the experience enabled them to interact with an unfamiliar and unique population as well as increased their understanding of other allied healthcare disciplines as a result of participation. No individual items nor the summary score exhibited statistical improvements over time. Conclusion: Overall, the intervention was successful in describing the IPE positive experiences and attitudes of undergraduate allied healthcare students when working in a senior adult population

Safe chainsaw operation

1 online resource (PDF, 6 pages)This archival publication may not reflect current scientific knowledge or recommendations. Current information available from the University of Minnesota Extension: https://www.extension.umn.edu

Safe landing layout and ise

1 online resource (PDF, 4 pages)This archival publication may not reflect current scientific knowledge or recommendations. Current information available from the University of Minnesota Extension: https://www.extension.umn.edu

Logging Hazard Survey

This archival publication may not reflect current scientific knowledge or recommendations. Current information available from the University of Minnesota Extension: https://www.extension.umn.edu

Modeling Adaptive Regulatory T-Cell Dynamics during Early HIV Infection

Regulatory T-cells (Tregs) are a subset of CD4+ T-cells that have been found to suppress the immune response. During HIV viral infection, Treg activity has been observed to have both beneficial and deleterious effects on patient recovery; however, the extent to which this is regulated is poorly understood. We hypothesize that this dichotomy in behavior is attributed to Treg dynamics changing over the course of infection through the proliferation of an ‘adaptive’ Treg population which targets HIV-specific immune responses. To investigate the role Tregs play in HIV infection, a delay differatial equation model was constructed to examine (1) the possible existence of two distinct Treg populations, normal (nTregs) and adaptive (aTregs), and (2) their respective effects in limiting viral load. Sensitivity analysis was performed to test parameter regimes that show the proportionality of viral load with adaptive regulatory populations and also gave insight into the importance of downregulation of CD4+ cells by normal Tregs on viral loads. Through the inclusion of Treg populations in the model, a diverse array of viral dynamics was found. Specifically, oscillatory and steady state behaviors were both witnessed and it was seen that the model provided a more accurate depiction of the effector cell population as compared with previous models. Through further studies of adaptive and normal Tregs, improved treatments for HIV can be constructed for patients and the viral mechanisms of infection can be further elucidated

Time to Evolve? Potential Evolutionary Responses of Fraser River Sockeye Salmon to Climate Change and Effects on Persistence

Evolutionary adaptation affects demographic resilience to climate change but few studies have attempted to project changes in selective pressures or quantify impacts of trait responses on population dynamics and extinction risk. We used a novel individual-based model to explore potential evolutionary changes in migration timing and the consequences for population persistence in sockeye salmon Oncorhynchus nerka in the Fraser River, Canada, under scenarios of future climate warming. Adult sockeye salmon are highly sensitive to increases in water temperature during their arduous upriver migration, raising concerns about the fate of these ecologically, culturally, and commercially important fish in a warmer future. Our results suggest that evolution of upriver migration timing could allow these salmon to avoid increasingly frequent stressful temperatures, with the odds of population persistence increasing in proportion to the trait heritability and phenotypic variance. With a simulated 2°C increase in average summer river temperatures by 2100, adult migration timing from the ocean to the river advanced by ∼10 days when the heritability was 0.5, while the risk of quasi-extinction was only 17% of that faced by populations with zero evolutionary potential (i.e., heritability fixed at zero). The rates of evolution required to maintain persistence under simulated scenarios of moderate to rapid warming are plausible based on estimated heritabilities and rates of microevolution of timing traits in salmon and related species, although further empirical work is required to assess potential genetic and ecophysiological constraints on phenological adaptation. These results highlight the benefits to salmon management of maintaining evolutionary potential within populations, in addition to conserving key habitats and minimizing additional stressors where possible, as a means to build resilience to ongoing climate change. More generally, they demonstrate the importance and feasibility of considering evolutionary processes, in addition to ecology and demography, when projecting population responses to environmental change