5,863 research outputs found
Respiration Rates of Two Midge Species at Different Temperatures
Respiration values for Chironomus n. sp. ranged from 0.11 mm³ O₂ /mg/hr at 5C to 0.44 mm³ O₂. /gm/hr at 25C. The range for Chaoborus punctipennis was from 0.15 mm³ O₂ /mg/hr at 5C to 0.56 mm³ O₂ /mg/hr at 25C. These low respiratory rates allow the two species to withstand low oxygen tensions for extended periods of time. Reflecting this ability, both species attained their greatest numerical and biomass values in the profundal regions of three strip-mine lakes whose lower waters become oxygen depleted during thermal stratification
Sample sizes for cancer trials where Health Related Quality of Life is the primary outcome
Health Related Quality of Life (HRQoL) instruments are increasingly important in evaluating health care, especially in cancer trials. When planning a trial, one essential step is the calculation of a sample size, which will allow a reasonable chance (power) of detecting a pre-specified difference (effect size) at a given level of statistical significance. It is almost mandatory to include this calculation in research protocols. Many researchers quote means and standard deviations to determine effect sizes, and assume the data will have a Normal distribution to calculate their required sample size. We have investigated the distribution of scores for two commonly used HRQoL instruments completed by lung cancer patients, and have established that scores do not have the Normal distribution form. We demonstrate that an assumption of Normality can lead to unrealistically sized studies. Our recommendation is to use a technique that is based on the fact that the HRQoL data are ordinal and makes minimal but realistic assumptions. © 2000 Cancer Research Campaig
SAGA: A project to automate the management of software production systems
The SAGA system is a software environment that is designed to support most of the software development activities that occur in a software lifecycle. The system can be configured to support specific software development applications using given programming languages, tools, and methodologies. Meta-tools are provided to ease configuration. The SAGA system consists of a small number of software components that are adapted by the meta-tools into specific tools for use in the software development application. The modules are design so that the meta-tools can construct an environment which is both integrated and flexible. The SAGA project is documented in several papers which are presented
Light ion isotope identification in space using a pixel detector based single layer telescope
Citation: Kroupa, M., Bahadori, A. A., Campbell-Ricketts, T., George, S. P., Stoffle, N., & Zeitlin, C. (2018). Light ion isotope identification in space using a pixel detector based single layer telescope. Applied Physics Letters, 113(17), 174101. https://doi.org/10.1063/1.5052907It is demonstrated that modern pixel detectors can be utilized as single-layer particle telescopes, offering details of a particle's stopping power evolution surpassing those provided by multi-layer, non-pixelated instruments. For particles that stop in the detector, this advantage arises from repeatably sampling the Bragg curve: we always know which part of the Bragg peak was measured. We can then create a dE/dx1 vs dE/dx2 plot where the stopping power at the beginning and the end of the track is compared. We are able to identify and analyze several fine-grained features on such plots, including several related to particles that stop inside the detector, termed “stopping.” Using data from an instrument aboard the International Space Station, we show that different isotopes of stopping hydrogen can be identified as their stopping powers differ. Other features of the dE/dx1 vs dE/dx2 plot not resolvable in multi-layer particle telescopes are also exhibited, such as nuclear interactions that occur within the sensor active volume
Circulating endothelial cell-derived extracellular vesicles mediate the acute phase response and sickness behaviour associated with CNS inflammation.
Brain injury elicits a systemic acute-phase response (APR), which is responsible for co-ordinating the peripheral immunological response to injury. To date, the mechanisms responsible for signalling the presence of injury or disease to selectively activate responses in distant organs were unclear. Circulating endogenous extracellular vesicles (EVs) are increased after brain injury and have the potential to carry targeted injury signals around the body. Here, we examined the potential of EVs, isolated from rats after focal inflammatory brain lesions using IL-1β, to activate a systemic APR in recipient naïve rats, as well as the behavioural consequences of EV transfer. Focal brain lesions increased EV release, and, following isolation and transfer, the EVs were sequestered by the liver where they initiated an APR. Transfer of blood-borne EVs from brain-injured animals was also enough to suppress exploratory behaviours in recipient naïve animals. EVs derived from brain endothelial cell cultures treated with IL-1β also activated an APR and altered behaviour in recipient animals. These experiments reveal that inflammation-induced circulating EVs derived from endothelial cells are able to initiate the APR to brain injury and are sufficient to generate the associated sickness behaviours, and are the first demonstration that EVs are capable of modifying behavioural responses
Correlates of exercise motivation and behavior in a population-based sample of endometrial cancer survivors: an application of the Theory of Planned Behavior
<p>Abstract</p> <p>Background</p> <p>Despite evidence of the benefits of exercise in cancer survivors, exercise participation rates tend to decline after treatments. Few studies have examined the determinants of exercise in less common cancer sites. In this study, we examined medical, demographic, and social cognitive correlates of exercise in endometrial cancer survivors using the Theory of Planned Behavior (TPB).</p> <p>Methods</p> <p>A mailed survey was completed by 354 endometrial cancer survivors (1 to 10 years postdiagnosis) residing in Alberta, Canada. The study was cross-sectional. Exercise behavior was assessed using the Godin Leisure Time Exercise Questionnaire and the TPB constructs were assessed with standard self-report scales. Multiple regression analyses were used to determine the independent associations of the TPB constructs with intention and behavior.</p> <p>Results</p> <p>Chi-square analyses indicated that marital status (<it>p </it>= .003), income level (<it>p </it>= .013), and body mass index (BMI) (<it>p </it>= .020) were associated with exercise. The TPB explained 34.1% of the variance in exercise behavior with intention (<it>β </it>= .38, <it>p </it>< .001) and self-efficacy (<it>β </it>= .18, <it>p </it>= .029) being independent correlates. For intention, 38.3% of the variance was explained by the TPB with self-efficacy (<it>β </it>= .34, <it>p </it>< .001) and affective attitude (<it>β </it>= .30, <it>p </it>< .001) being the independent correlates. The TPB mediated the associations of marital status and BMI with exercise but not income level. Age and BMI moderated the associations of the TPB with intention and behavior.</p> <p>Conclusion</p> <p>The TPB may be a useful framework for understanding exercise in endometrial cancer survivors. Exercise behavior change interventions based on the TPB should be tested in this growing population.</p
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