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Selected AbstractsDevelopment, growth, and egg production of Ageneotettix deorum (Orthoptera: Acrididae) in response to spider predation risk and elevated resource qualityECOLOGICAL ENTOMOLOGY, Issue 1 2004Bradford. Abstract., 1.,Predation risk to insects is often size- or stage-selective and usually decreases as prey grow. Any factor, such as food quality, that accelerates developmental and growth rates is likely to reduce the period over which prey are susceptible to size-dependent predation. 2.,Using field experiments, several hypotheses that assess growth, development, and egg production rates of the rangeland grasshopper Ageneotettix deorum (Scudder) were tested in response to combinations of food quality and predation risk from wolf spiders to investigate performance variation manifested through a behaviourally mediated path affecting food ingestion rates. 3.,Grasshoppers with nutritionally superior food completed development , 8,18% faster and grew 15,45% larger in the absence of spiders, in comparison with those subjected to low quality food exposed to spider predators. Growth and development did not differ for grasshoppers feeding on high quality food when predators were present in comparison with lower quality food unimpeded by predators. Responses indicated a compensatory relationship between resource quality and predation risk. 4.,Surviving grasshoppers produced fewer eggs compared with individuals not exposed to spiders. Because no differences were found in daily egg production rate regardless of predation treatment, lower egg production was attributed to delayed age of first reproduction. Results compare favourably with responses observed in natural populations. 5.,Risk of predation from spiders greatly reduced growth, development, and ultimately egg production. Increased food quality counteracts the impact of predation risk on grasshoppers through compensatory responses, suggesting that bottom-up factors mediate effects of spiders. [source] Effects of insular cortex lesions on conditioned taste aversion and latent inhibition in the ratEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 9 2007Christopher Roman Abstract The present study tested the hypothesis that lesions of the insular cortex of the rat retard the acquisition of conditioned taste aversions (CTAs) because of an impairment in the detection of the novelty of taste stimuli. Demonstrating the expected latent inhibition effect, nonlesioned control subjects acquired CTAs more rapidly when the conditioned stimulus (0.15% sodium saccharin) was novel rather than familiar (achieved by pre-exposure to the to-be-conditioned taste cue). However, rats with insular cortex lesions acquired taste aversions at the same slow rate regardless of whether the saccharin was novel or familiar. The pattern of behavioural deficits obtained cannot be interpreted as disruptions of taste detection or stimulus intensity, but is consistent with the view that insular cortex lesions disrupt taste neophobia, a dysfunction that consequently retards CTA acquisition because of a latent inhibition-like effect. [source] Efficient scheduling discipline for Hierarchical Diff-EDFINTERNATIONAL JOURNAL OF NETWORK MANAGEMENT, Issue 3 2008Moutaz Saleh Packet networks are currently enabling the integration of traffic with a wide range of characteristics that extend from video traffic with stringent quality of service (QoS) requirements to the best-effort traffic requiring no guarantees. QoS guarantees can be provided in conventional packet networks by the use of proper packet-scheduling algorithms. As a computer revolution, many scheduling algorithms have been proposed to provide different schemes of QoS guarantees, with Earliest Deadline First (EDF) as the most popular one. With EDF scheduling, all flows receive the same miss rate regardless of their traffic characteristics and deadlines. This makes the standard EDF algorithm unsuitable for situations in which the different flows have different miss rate requirements since in order to meet all miss rate requirements it is necessary to limit admissions so as to satisfy the flow with the most stringent miss rate requirements. In this paper, we propose a new priority assignment scheduling algorithm, Hierarchal Diff-EDF (Differentiate Earliest Deadline First), which can meet the real-time needs of these applications while continuing to provide best-effort service to non-real time traffic. The Hierarchal Diff-EDF features a feedback control mechanism that detects overload conditions and modifies packet priority assignments accordingly. Copyright © 2007 John Wiley & Sons, Ltd. [source] Debugging Decomposition Data,Comparative Taphonomic Studies and the Influence of Insects and Carcass Size on Decomposition RateJOURNAL OF FORENSIC SCIENCES, Issue 1 2010Tal Simmons Ph.D. Abstract:, Comparison of data from a variety of environments and ambient temperatures has previously been difficult as few studies used standardized measures of time/temperature and decomposition. In this paper, data from previous studies and recent experiments are compared using simple conversions. These conversions allow comparison across multiple environments and experiments for the first time. Plotting decomposition score against logADD allows the exponential progression of decomposition to be expressed as a simple linear equation. Data comparison from many environments and temperatures shows no difference in decomposition progression when measured using Accumulated Degree Days. The major effector of change in rate was insect presence, regardless of depositional environment, species, or season. Body size is significant when carcasses are accessed by insects; when insects are excluded, while bodies are indoors, submerged, or buried, then decomposition progresses at the same rate regardless of body size. [source] Soil chemistry versus environmental controls on production of CH4 and CO2 in northern peatlandsEUROPEAN JOURNAL OF SOIL SCIENCE, Issue 2 2005J. B. Yavitt Summary Rates of organic carbon mineralization (to CO2 and CH4) vary widely in peat soil. We transplanted four peat soils with different chemical composition into six sites with different environmental conditions to help resolve the debate about control of organic carbon mineralization by resource availability (e.g. carbon and nutrient chemistry) versus environmental conditions (e.g. temperature, moisture, pH). The four peat soils were derived from Sphagnum (bog moss). Two transplant sites were in mid-boreal Alberta, Canada, two were in low-boreal Ontario, Canada, and two were in the temperate United States. After 3 years in the field, CH4 production varied significantly as a function of peat type, transplant site, and the type,site interaction. All four peat soils had very small rates of CH4 production (< 20 nmol g,1 day,1) after transplant into two sites, presumably caused by acid site conditions (pH < 4.0). One peat soil had small CH4 production rates regardless of transplant site. A canonical discriminant analysis revealed that large rates of CH4 production (4000 nmol g,1 day,1) correlated with large holocellulose content, a large concentration of p -hydroxyl phenolic compounds in the Klason lignin, and small concentrations of N, Ca and Mn in peat. Significant variation in rates of CO2 production correlated positively with holocellulose content and negatively with N concentrations, regardless of transplant site. The temperature response for CO2 production varied as a function of climate, being greater for peat formed in a cold climate, but did not apply to transplanted peat. Although we succeeded in elucidating some aspects of peat chemistry controlling production of CH4 and CO2 in Sphagnum -derived peat soils, we also revealed idiosyncratic combinations of peat chemistry and site conditions that will complicate forecasting rates of peat carbon mineralization into the future. [source] The effects of memory, attention, and executive dysfunction on outcomes of depression in a primary care intervention trial: the PROSPECT studyINTERNATIONAL JOURNAL OF GERIATRIC PSYCHIATRY, Issue 9 2007Hillary R. Bogner Abstract Objective To describe the influence of domains of cognition on remission and response of depression in an intervention trial among older primary care patients. Methods Twenty primary care practices were randomly assigned to Usual Care or to an Intervention consisting of a depression care manager offering algorithm-based care for depression. In all, 599 adults 60 years and older with a depression diagnosis were included in these analyses. Depression severity and remission of depression were assessed by the 24-item Hamilton Depression Rating Scale. The Mini-Mental State Examination (MMSE) was our global measure of cognitive function. Verbal memory was assessed with the memory subscale of the Dementia Rating Scale. Attention was measured with the digit span from the Weschler Adult Intelligence Test. Response inhibition, one of the executive functions, was assessed with the Stroop Color-Word test. Results The intervention was associated with improved remission and response rates regardless of cognitive impairment. Response inhibition as measured by the Stroop Color-Word test appeared to significantly modify the intervention versus usual care difference in remission and response at 4 months. Patients in the poorest performance quartile at baseline on the Stroop Color-Word test in the Intervention Condition were more likely to achieve remission of depression at 4 months than comparable patients in Usual Care [odds ratio (OR),=,17.76, 95% Confidence Interval (CI), 3.06, 103.1]. Conclusions Depressed older adults in primary care with executive dysfunction have low remission and response rates when receiving usual care but benefit from depression care management. Copyright © 2007 John Wiley & Sons, Ltd. [source] Tests of Association for Quantitative Traits in Nuclear Families Using Principal Components to Correct for Population StratificationANNALS OF HUMAN GENETICS, Issue 6 2009Lei Zhang SUMMARY Traditional transmission disequilibrium test (TDT) based methods for genetic association analyses are robust to population stratification at the cost of a substantial loss of power. We here describe a novel method for family-based association studies that corrects for population stratification with the use of an extension of principal component analysis (PCA). Specifically, we adopt PCA on unrelated parents in each family. We then infer principal components for children from those for their parents through a TDT-like strategy. Two test statistics within the variance-components model are proposed for association tests. Simulation results show that the proposed tests have correct type I error rates regardless of population stratification, and have greatly improved power over two popular TDT-based methods: QTDT and FBAT. The application to the Genetic Analysis Workshop 16 (GAW16) data sets attests to the feasibility of the proposed method. [source] | ||||||||||