616 research outputs found
Neuronal Responses to Water Flow in the Marine Slug Tritonia diomedea
The marine slug Tritonia diomedea mustrely on its ability to touch and smell in order to navigate because it is blind. The primaryfactor that influences its crawling direction is the direction of water flow (caused bytides in nature). The sensory cells that detect flow and determine flow directionhave not been identified. The lateral branch of Cerebral Nerve 2 (latCeN2) has beenidentified as the nerve that carries sensory axons to the brain from the flow receptors inthe oral tentacles. Backfilling this nerve to the brain resulted in the labeling of a numberof cells located throughout the brain. Most of the labeled cells are concentrated in the cerebral ganglion where the nerve enters thebrain. The medial and lateral branches of CeN2 were backfilled for comparison of thepattern of cells from each nerve. A map of the cells innervated by latCeN2 reveals thelocation of the stained cells. Extracellular recording from latCeN2 revealed itsinvolvement in the detection of water flow and orientation. The nerve becomes activein response to water flow stimulation. Intracellular recordings of the electricalactivity of these cells in a live animal will be the next step to determine if these cells arethe flow receptors
Avian Survey Methods for Use at Airports
Adverse effects and damage caused by interactions between humans and wildlife are increasing (DeStephana and DeGraaf 2003). To manage wildlife effectively- whether to mitigate damage. to enhance safety, or to reach conservation goals-wildlife biologists must identify hazards posed by or to members of a particular species (i.e., a population) or guild, and then prioritize management goals and specific actions. We examine the special problem of managing birds to reduce hazards to aviation, particularly those species known to cause structural damage to aircraft when struck and that ·pose problems to airport facilities (Dolbeer et al. 2000, Cleary and Dolbeer 2005, DeVault et al. 2011). Effective management of hazardous species at airports requires knowledge of species abundance and how abundance varies over time. In this context, the quality of the sampling methodology used will influence a biologist\u27s ability to accurately quantify avian hazards and to understand the ecological interactions of populations or guilds using airport environments
Avian Survey Methods for Use on Airports
Management of wildlife, whether to mitigate damage, enhance safety, or effect conservation goals, requires identification of hazards posed by or to members of a particular species population or guild, and prioritization of management goals. We examined the special problem of managing birds to reduce hazards to aviation, particularly those species known to cause structural damage to aircraft when struck, as well as posing problems to airport facilities. Our objectives were to synthesize sampling theory and methods to provide airport biologists with 1) means to design and implement an avian survey on an airport that will maximize accuracy in quantifying avian hazards; 2) an understanding of bias and precision, and their influences on quantification of avian hazards; 3) suggestions on how to quantify avian hazards and use these data to estimate relative risk posed to aviation safety by a particular species or guild by time period and habitat type; and 4) knowledge of how data can be used to prioritize management goals. Our recommendations are intended to compliment U.S. Federal Aviation Administration procedures for Wildlife Hazard Assessments and subsequent management on airports. We stress the need for survey data to be ecologically relevant and accurate, such that management guidelines are defensible. However, we recognize that “real world” issues, such as regulatory, labor, and financial constraints, as well as the dynamics of airport environments, inevitably influence survey methods. Though we do not advocate use of naive count data in estimating relative abundance or habitat use, we recognize that animal observations obtained by airport biologists outside of a standardized sampling protocol are critical for identifying potential hazards to aviation safety. We recommend field testing of our suggestions and development of training materials for airport biologists that distill the information that we will present in light of constraints affecting survey design and conduct
Improved Laboratory Transition Probabilities for Neutral Chromium and Re-determination of the Chromium Abundance for the Sun and Three Stars
Branching fraction measurements from Fourier transform spectra in conjunction
with published radiative lifetimes are used to determine transition
probabilities for 263 lines of neutral chromium. These laboratory values are
employed to derive a new photospheric abundance for the Sun: log (Cr
I) = 5.640.01 (). These Cr I solar abundances do
not exhibit any trends with line strength nor with excitation energy and there
were no obvious indications of departures from LTE. In addition, oscillator
strengths for singly-ionized chromium recently reported by the FERRUM Project
are used to determine: log (Cr II) = 5.770.03 (). Transition probability data are also applied to the spectra of three
stars: HD 75732 (metal-rich dwarf), HD 140283 (metal-poor subgiant), and CS
22892-052 (metal-poor giant). In all of the selected stars, Cr I is found to be
underabundant with respect to Cr II. The possible causes for this abundance
discrepancy and apparent ionization imbalance are discussed.Comment: 44 pages, 6 figure
L-citrulline supplementation improves O2 uptake kinetics and high-intensity exercise performance in humans
This is the author accepted manuscript. The final version is available from the American Physiological Society via the DOI in this record.The purpose of this study was to compare the effects of L-citrulline (CIT) and L-arginine (ARG) supplementation on nitric oxide (NO) biomarkers, pulmonary O2 uptake (VO2) kinetics and exercise performance. In a randomised, placebo-controlled, cross-over study, ten healthy adult males completed moderate- and severe-intensity cycling exercise on days 6 and 7 of a 7 day supplementation period with placebo (PLA), 6 g•day(-1) of ARG and 6 g•day(-1) of CIT. Compared to PLA, plasma [ARG] was increased by a similar magnitude with ARG and CIT supplementation, but plasma [CIT] was only increased (P0.05). In conclusion, these results suggest that short-term CIT, but not ARG, supplementation can improve blood pressure, VO2 kinetics and exercise performance in healthy adults
Reductions of Hidden Information Sources
In all but special circumstances, measurements of time-dependent processes
reflect internal structures and correlations only indirectly. Building
predictive models of such hidden information sources requires discovering, in
some way, the internal states and mechanisms. Unfortunately, there are often
many possible models that are observationally equivalent. Here we show that the
situation is not as arbitrary as one would think. We show that generators of
hidden stochastic processes can be reduced to a minimal form and compare this
reduced representation to that provided by computational mechanics--the
epsilon-machine. On the way to developing deeper, measure-theoretic foundations
for the latter, we introduce a new two-step reduction process. The first step
(internal-event reduction) produces the smallest observationally equivalent
sigma-algebra and the second (internal-state reduction) removes sigma-algebra
components that are redundant for optimal prediction. For several classes of
stochastic dynamical systems these reductions produce representations that are
equivalent to epsilon-machines.Comment: 12 pages, 4 figures; 30 citations; Updates at
http://www.santafe.edu/~cm
Positive Imagery-Based Cognitive Bias Modification as a Web-Based Treatment Tool for Depressed Adults: A Randomized Controlled Trial.
Depression is a global health problem requiring treatment innovation. Targeting neglected cognitive aspects may provide a useful route. We tested a cognitive-training paradigm using positive mental imagery (imagery cognitive bias modification, imagery CBM), developed via experimental psychopathology studies, in a randomized controlled trial. Training was delivered via the Internet to 150 individuals with current major depression. Unexpectedly, there was no significant advantage for imagery CBM compared with a closely matched control for depression symptoms as a whole in the full sample. In exploratory analyses, compared with the control, imagery CBM significantly improved anhedonia over the intervention and improved depression symptoms as a whole for those participants with fewer than five episodes of depression and those who engaged to a threshold level of imagery. Results suggest avenues for improving imagery CBM to inform low-intensity treatment tools for depression. Anhedonia may be a useful treatment target for future work
The effect of Staphylococcus aureus carriage in late pregnancy on antibody levels to staphylococcal toxins in cord blood and breast milk.
We investigated the effect of carriage of Staphylococcus aureus in the later stages of pregnancy on levels of antibody specific to the S. aureus toxins, staphylococcal enterotoxin B (SEB), staphylococcal enterotoxin C (SEC) and toxic shock syndrome toxin-1 (TSST-1), in cord blood and breast milk and also explored the relationship between levels of antibody in antenatal serum and cord blood. Nasopharyngeal swabs and stool samples were collected on two occasions, from 96 women, during the last 6 weeks of pregnancy. Samples were cultured and S. aureus isolates were identified. Antenatal and cord blood samples from the same women and their infants were analysed for IgG antibody to SEB, SEC and TSST-1 by enzyme-linked immunosorbent assay. Breast milk samples were analysed for IgA antibody to the same toxins. We found that S. aureus carriage in pregnancy is common and exposure to a toxin-producing isolate boosts immunity. Over 89% of women and infants have some protective antibody to the toxins, and antitoxin IgG levels are higher in cord blood samples compared with antenatal samples. Levels of cord blood IgG and breast milk IgA specific for the staphylococcal toxins vary. Some infants lack protection and could be at risk of toxin-induced disease
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