Restoration and Monitoring of the River Otter Population in Iowa

Northern river otters (Lontra canadensis) were widespread in North America at the time of European settlement. However, river otters were extirpated from most of Iowa in the early 1900s due to habitat degradation and unregulated harvest. In 1985, the Iowa Department of Natural Resources began an effort to restore the river otter population throughout the state, including a pilot study of survival to determine if establishment was feasible. Annual survival was estimated to be 86% during the pilot study. River otters dispersed an average of about 11 km from the point of release and exhibited habitat use typical for the species. Based on the successful pilot study, 261 river otters were released in the state of Iowa from 1986-2001. More recently we examined the age structure and reproductive effort of 81 river otters (43 females and 38 males) collected in Iowa from 1999-2001 to document the characteristics of the reestablished population. We found that 41% of the otters sampled were juveniles, 38% were yearlings and 21% were adults. Fifty-five percent of all female otters were pregnant, and 80% of adult females were pregnant. We observed a mean of 2.9 corpora lutea/female and calculated that female’s ≥ 1 year old could potentially produce an average 5.7 female offspring during an average life span. Based on the widespread distribution, healthy reproductive characteristics, and high survival rates it is feasible that a limited harvest of river otter could be implemented in Iowa

A High Power Hydrogen Target for Parity Violation Experiments

Parity-violating electron scattering measurements on hydrogen and deuterium, such as those underway at the Bates and CEBAF laboratories, require luminosities exceeding $10^{38}$cm$^{-2}$s$^{-1}$, resulting in large beam power deposition into cryogenic liquid. Such targets must be able to absorb 500 watts or more with minimal change in target density. A 40~cm long liquid hydrogen target, designed to absorb 500~watts of beam power without boiling, has been developed for the SAMPLE experiment at Bates. In recent tests with 40~$\mu$A of incident beam, no evidence was seen for density fluctuations in the target, at a sensitivity level of better than 1\%. A summary of the target design and operational experience will be presented.Comment: 13 pages, 9 postscript figure

CaMKII tethers to L-type Ca(2+) channels, establishing a local and dedicated integrator of Ca(2+) signals for facilitation

Ca(2+)-dependent facilitation (CDF) of voltage-gated calcium current is a powerful mechanism for up-regulation of Ca(2+) influx during repeated membrane depolarization. CDF of L-type Ca(2+) channels (Ca(v)1.2) contributes to the positive force–frequency effect in the heart and is believed to involve the activation of Ca(2+)/calmodulin-dependent kinase II (CaMKII). How CaMKII is activated and what its substrates are have not yet been determined. We show that the pore-forming subunit α(1C) (Ca(v)α1.2) is a CaMKII substrate and that CaMKII interaction with the COOH terminus of α(1C) is essential for CDF of L-type channels. Ca(2+) influx triggers distinct features of CaMKII targeting and activity. After Ca(2+)-induced targeting to α(1C), CaMKII becomes tightly tethered to the channel, even after calcium returns to normal levels. In contrast, activity of the tethered CaMKII remains fully Ca(2+)/CaM dependent, explaining its ability to operate as a calcium spike frequency detector. These findings clarify the molecular basis of CDF and demonstrate a novel enzymatic mechanism by which ion channel gating can be modulated by activity

The evolution of representation in simple cognitive networks

Representations are internal models of the environment that can provide guidance to a behaving agent, even in the absence of sensory information. It is not clear how representations are developed and whether or not they are necessary or even essential for intelligent behavior. We argue here that the ability to represent relevant features of the environment is the expected consequence of an adaptive process, give a formal definition of representation based on information theory, and quantify it with a measure R. To measure how R changes over time, we evolve two types of networks---an artificial neural network and a network of hidden Markov gates---to solve a categorization task using a genetic algorithm. We find that the capacity to represent increases during evolutionary adaptation, and that agents form representations of their environment during their lifetime. This ability allows the agents to act on sensorial inputs in the context of their acquired representations and enables complex and context-dependent behavior. We examine which concepts (features of the environment) our networks are representing, how the representations are logically encoded in the networks, and how they form as an agent behaves to solve a task. We conclude that R should be able to quantify the representations within any cognitive system, and should be predictive of an agent's long-term adaptive success.Comment: 36 pages, 10 figures, one Tabl

Going places

Journeys. We all make them. Often they take us to exotic places. Sometimes they take us even further. They might take us through time. Or they might take us into a new way of life. There are times too, when we go all over the world and back again only to find that home is, after all, where it’s all happening. This book contains stories about many different types of journey. We hope you will enjoy travelling into it and finding a world that suits you

Hydrodynamic dispersion within porous biofilms

Many microorganisms live within surface-associated consortia, termed biofilms, that can form intricate porous structures interspersed with a network of fluid channels. In such systems, transport phenomena, including flow and advection, regulate various aspects of cell behavior by controlling nutrient supply, evacuation of waste products, and permeation of antimicrobial agents. This study presents multiscale analysis of solute transport in these porous biofilms. We start our analysis with a channel-scale description of mass transport and use the method of volume averaging to derive a set of homogenized equations at the biofilm-scale in the case where the width of the channels is significantly smaller than the thickness of the biofilm. We show that solute transport may be described via two coupled partial differential equations or telegrapher's equations for the averaged concentrations. These models are particularly relevant for chemicals, such as some antimicrobial agents, that penetrate cell clusters very slowly. In most cases, especially for nutrients, solute penetration is faster, and transport can be described via an advection-dispersion equation. In this simpler case, the effective diffusion is characterized by a second-order tensor whose components depend on (1) the topology of the channels' network; (2) the solute's diffusion coefficients in the fluid and the cell clusters; (3) hydrodynamic dispersion effects; and (4) an additional dispersion term intrinsic to the two-phase configuration. Although solute transport in biofilms is commonly thought to be diffusion dominated, this analysis shows that hydrodynamic dispersion effects may significantly contribute to transport

The Strange Quark Contribution to the Proton's Magnetic Moment

We report a new determination of the strange quark contribution to the proton's magnetic form factor at a four-momentum transfer Q2 = 0.1 (GeV/c)^2 from parity-violating e-p elastic scattering. The result uses a revised analysis of data from the SAMPLE experiment which was carried out at the MIT-Bates Laboratory. The data are combined with a calculation of the proton's axial form factor GAe to determine the strange form factor GMs(Q2=0.1)=0.37 +- 0.20 +- 0.26 +- 0.07. The extrapolation of GMs to its Q2=0 limit and comparison with calculations is also discussed.Comment: 6 pages, 1 figure, submitted to Phys. Lett.

The coMforT study of a trauma-informed mindfulness intervention for women who have experienced domestic violence and abuse:a protocol for an intervention refinement and individually randomised parallel feasibility trial

Background Domestic violence and abuse (DVA) is common and destructive to health. Post-traumatic stress disorder (PTSD) is a major mental health consequence of DVA. People who have experienced DVA have specific needs, arising from the repeated and complex nature of the trauma. The National Institute for Health and Care Excellence recommends more research on the effectiveness of psychological interventions for people who have experienced DVA. There is growing evidence that mindfulness-based interventions may help trauma symptoms. Methods Intervention refinement and randomized controlled feasibility trial. A prototype trauma-informed mindfulness-based cognitive therapy (TI-MBCT) intervention will be co-produced following qualitative interviews and consensus exercise with stakeholders. Participants in the feasibility trial will be recruited from DVA agencies in two geographical regions and randomized to receive either TI-MBCT or usual care (self-referral to the Improving Access to Psychological Therapies (IAPT) service). TI-MBCT will be delivered as a group-based eight-week program. It will not be possible to blind the participants or the assessors to the study allocation. The following factors will inform the feasibility of progressing to a fully powered trial: recruitment, retention, intervention fidelity, and the acceptability of the intervention and trial design to participants. We will also test the feasibility of measuring the following participant outcomes before and 6 months post-randomization: PTSD, dissociative symptoms, depression, anxiety, DVA re-victimization, self-compassion, and mother-reported child health. Process evaluation and economic analysis will be embedded within the feasibility trial. Discussion This study will lead to the development of a TI-MBCT intervention for DVA survivors with PTSD and inform the feasibility and design of a fully powered randomized controlled trial (RCT). The full trial will aim to determine the effectiveness and cost-effectiveness of a TI-MBCT intervention in improving the clinically important symptoms of PTSD in DVA survivors

Qweak: A Precision Measurement of the Proton's Weak Charge

The Qweak experiment at Jefferson Lab aims to make a 4% measurement of the parity-violating asymmetry in elastic scattering at very low $Q^2$ of a longitudinally polarized electron beam on a proton target. The experiment will measure the weak charge of the proton, and thus the weak mixing angle at low energy scale, providing a precision test of the Standard Model. Since the value of the weak mixing angle is approximately 1/4, the weak charge of the proton $Q_w^p = 1-4 \sin^2 \theta_w$ is suppressed in the Standard Model, making it especially sensitive to the value of the mixing angle and also to possible new physics. The experiment is approved to run at JLab, and the construction plan calls for the hardware to be ready to install in Hall C in 2007. The theoretical context of the experiment and the status of its design are discussed.Comment: 5 pages, 2 figures, LaTeX2e, to be published in CIPANP 2003 proceeding