Showing papers by "University of Saskatchewan published in 2001"

The vasorelaxant effect of H2S as a novel endogenous gaseous KATP channel opener

Abstract: Hydrogen sulfide (H(2)S) has been traditionally viewed as a toxic gas. It is also, however, endogenously generated from cysteine metabolism. We attempted to assess the physiological role of H(2)S in the regulation of vascular contractility, the modulation of H(2)S production in vascular tissues, and the underlying mechanisms. Intravenous bolus injection of H(2)S transiently decreased blood pressure of rats by 12- 30 mmHg, which was antagonized by prior blockade of K(ATP) channels. H(2)S relaxed rat aortic tissues in vitro in a K(ATP) channel-dependent manner. In isolated vascular smooth muscle cells (SMCs), H(2)S directly increased K(ATP) channel currents and hyperpolarized membrane. The expression of H(2)S-generating enzyme was identified in vascular SMCs, but not in endothelium. The endogenous production of H(2)S from different vascular tissues was also directly measured with the abundant level in the order of tail artery, aorta and mesenteric artery. Most importantly, H(2)S production from vascular tissues was enhanced by nitric oxide. Our results demonstrate that H(2)S is an important endogenous vasoactive factor and the first identified gaseous opener of K(ATP) channels in vascular SMCs.

The Faces Pain Scale-Revised: toward a common metric in pediatric pain measurement.

Abstract: The Faces Pain Scale (FPS; Bieri et al., Pain 41 (1990) 139) is a self-report measure used to assess the intensity of children's pain. Three studies were carried out to revise the original scale and validate the adapted version. In the first phase, the FPS was revised from its original seven faces to six, while maintaining its desirable psychometric properties, in order to make it compatible in scoring with other self-rating and observational scales which use a common metric (0–5 or 0–10). Using a computer-animated version of the FPS developed by Champion and colleagues (Sydney Animated Facial Expressions Scale), psychophysical methods were applied to identify four faces representing equal intervals between the scale values representing least pain and most pain. In the second phase, children used the new six-face Faces Pain Scale – Revised (FPS-R) to rate the intensity of pain from ear piercing. Its validity is supported by a strong positive correlation (r=0.93, N=76) with a visual analogue scale (VAS) measure in children aged 5–12 years. In the third phase, a clinical sample of pediatric inpatients aged 4–12 years used the FPS-R and a VAS or the colored analogue scale (CAS) to rate pain during hospitalization for surgical and non-surgical painful conditions. The validity of the FPS-R was further supported by strong positive correlations with the VAS (r=0.92, N=45) and the CAS (r=0.84, N=45) in this clinical sample. Most children in all age groups including the youngest were able to use the FPS-R in a manner that was consistent with the other measures. There were no significant differences between the means on the FPS-R and either of the analogue scales. The FPS-R is shown to be appropriate for use in assessment of the intensity of children's acute pain from age 4 or 5 onward. It has the advantage of being suitable for use with the most widely used metric for scoring (0–10), and conforms closely to a linear interval scale.

Progressive supranuclear palsy: clinical features, pathophysiology and management.

Abstract: Progressive supranuclear palsy (PSP) is a degenerative condition of unknown aetiology that produces an akinetic-rigid form of parkinsonism characterised by early falls and abnormalities of extraocular movements. Mean age of onset is approximately 63 years, and mean survival from symptom onset is 9 years. Men are much more frequently affected than women. The classic clinical finding is supranuclear ophthalmoplegia, which may not present until late in the illness, if at all. The clinical diagnosis of PSP can be difficult to make, as the sites of pathology are heterogeneous. Structural and functional neuroimaging studies, although not specific for PSP, may be of some assistance in making the diagnosis. The definitive diagnosis of PSP requires the presence of both clinical and neuropathological evidence. Multiple anatomical sites are affected in PSP. The most consistently involved are the subthalamic nucleus, globus pallidus interna and externa, pontine nuclei, periaqueductal grey matter and the substantia nigra. The location of the pathology accounts for the clinical features. The histological hallmark of PSP is the presence of globose neurofibrillary tangles in the affected subcortical nuclei. Neurofibrillary tangles are composed of abnormally phosphorylated tau, a microtubule-associated protein that is involved in maintenance of the cytoskeleton. Abnormalities near or in the gene coding for tau are implicated in the pathogenesis of PSP. The multiple neurotransmitter abnormalities, including those affecting dopamine, acetylcholine, γ-aminobutyric acid and norepinephrine (noradrenaline) systems and pathways, as well as both pre- and post-synaptic pathology, make pharmacological therapy of PSP a challenge. Although an individual patient may respond to a drug, in general patients with PSP have a minimal response and a short duration of sustained benefit.

Remote Sensing for Sustainable Forest Management

Abstract: INTRODUCTION Forest Management Questions Remote Sensing Data and Methods Categories of Applications of Remote Sensing Organization of the Book SUSTAINABLE FOREST MANAGEMENT Definition of Sustainable Forest Management Ecosystem Management Criteria and Indicators of Sustainable Forest Management Information Needs of Forest Managers Role of Remote Sensing ACQUISITION OF IMAGERY Field, Aerial, and Satellite Imagery Data Characteristics Resolution and Scale Aerial Platforms and Sensors Satellite Platforms and Sensors General Limits of Airborne and Satellite Remote Sensing Data IMAGE CALIBRATION AND PROCESSING Georadiometric Effects and Spectral Response Image Processing Systems and Functionality Image Analysis Support Functions Image Information Extraction Image Understanding FOREST MODELING AND GIS Geographical Information Science Ecosystem Process Models Spatial Pattern Modeling FOREST CLASSIFICATION Information on Forest Classes Classification Systems for Use with Remote Sensing Data Level I Classes Level II Classes Level III Classes FOREST STRUCTURE ESTIMATION Information on Forest Structure Forest Inventory Variables Biomass Volume and Growth Assessment FOREST CHANGE DETECTION Information on Forest Change Harvesting and Silviculture Activity Natural Disturbances Change in Spatial Structure CONCLUSION The Technological Approach - Revisited References

Environmental Impact Assessment

Abstract: Environmental impact assessment (EIA) is a systematic process designed to identify and predict the potential impacts of human activity on the biophysical and human environment. It also functions as an environmental management tool to identify measures to avoid, mitigate or compensate for those effects. EIA is intended to be an iterative process to follow-up to projects postimplementation to determine actual environmental outcomes, interpret and communicate information about those outcomes and investigate opportunities for improved project environmental performance. Originating from the United States’ National Environmental Policy Act of 1970, EIA is now amongst the most successful and widely practiced environmental management tools in the world. Key Concepts: EIA is an aid to decision making through which concerns about the potential environmental consequences of proposed projects are assessed before those projects become a reality. Screening in EIA ensures that assessments are done when needed and not done when not needed. Scope is essential to good EIA and the goal is to focus on a select set of environmental components that are deemed important from scientific, public or regulatory perspectives and are likely to be adversely affected by the project. The underlying intent of EIA is to allow project proponents, managers and decision makers to enhance the benefits of proposed development projects and to mitigate potentially adverse impacts to the point of acceptability. EIA must be applied early in the development planning processes if it is to be influential in project design and decision making. Information gained in EIA follow-up studies, after the project is implemented, provides feedback to improve predictions and mitigation and management programmes, and an opportunity to learn for subsequent project proposals. Keywords: environmental impact assessment; baseline studies; impact prediction; mitigation and management of impacts; cumulative environmental effects; follow-up studies

Cytokinin production by plant growth promoting rhizobacteria and selected mutants

Abstract: One of the proposed mechanisms by which rhizobacteria enhance plant growth is through the production of plant growth regulators. Five plant growth promoting rhizobacterial (PGPR) strains produced the cytokinin dihydrozeatin riboside (DHZR) in pure culture. Cytokinin production by Pseudomonas fluorescens G20-18, a rifampicin-resistant mutant (RIF), and two TnphoA-derived mutants (CNT1, CNT2), with reduced capacity to synthesize cytokinins, was further characterized in pure culture using immunoassay and thin layer chromatography. G20-18 produced higher amounts of three cytokinins, isopentenyl adenosine (IPA), trans-zeatin ribose (ZR), and DHZR than the three mutants during stationary phase. IPA was the major metabolite produced, but the proportion of ZR and DHZR accumulated by CNT1 and CNT2 increased with time. No differences were observed between strain G20-18 and the mutants in the amounts of indole acetic acid synthesized, nor were gibberellins detected in supernatants of any of the strains. Addition of 10(-5) M adenine increased cytokinin production in 96- and 168-h cultures of strain G20-18 by approximately 67%. G20-18 and the mutants CNT1 and CNT2 may be useful for determination of the role of cytokinin production in plant growth promotion by PGPR.

Cognitive arithmetic across cultures.

Abstract: Canadian university students either of Chinese origin (CC) or non-Asian origin (NAC) and Chinese university students educated in Asia (AC) solved simple-arithmetic problems in the 4 basic operations (e.g., 3 + 4, 7 - 3, 3 X 4, 12 •*• 3) and reported their solution strategies. They also completed a standardized test of more complex multistep arithmetic. For complex arithmetic, ACs outperformed both CCs and NACs. For simple arithmetic, however, ACs and CCs were equal and both performed better than NACs. The superior simple-arithmetic skills of CCs relative to NACs implies that extracurricular culture-specific factors rather than differences in formal education explain the simple-arithmetic advantage for Chinese relative to non-Asian North American adults. NAC's relatively poor simple-arithmetic performance resulted both from less efficient retrieval skills and greater use of procedural strategies. Nonetheless, all 3 groups reported using procedures for the larger simple subtraction and division problems, confirming the importance of procedural knowledge in skilled adults' performance of elementary mathematics. Knowledge of elementary arithmetic (i.e., simple addition, multiplication, subtraction, and division) is a pervasive requirement of everyday modern life, providing the essential means for dealing with a widely diverse variety of numerical-problem-solving situations. Basic arithmetic also provides the foundation for the more advanced mathematical skills that are central to all modern scientific disciplines. Consequently, understanding this fundamental intellectual skill is an important goal for cognitive science (Ashcraft, 1995; Geary, 1994). In this study, Chinese adults educated in the People's Republic of China and Canadian adults educated in Canada, either of Chinese or non-Asian origin, solved simple arithmetic problems involving the four basic operations (e.g., 3 + 4, 7 - 3, 3 X 4, 12 -=- 3). Participants also reported their strategy (i.e., direct memory retrieval vs. procedural strategies) after each problem. The purpose was to address three important questions of current research in cognitive arithmetic. First, when adults solve simple-arithmetic problems, what is the relative balance of direct memory retrieval versus use of procedural strategies such as counting or transformation (e.g., 6 + 7 = 6 + 6+1 = 13)? Recent evidence suggests that even skilled adults make substantial use of procedures (e.g., LeFevre, Sadesky, & Bisanz, 1996), but no study has attempted to assess this for the entire domain of elementary arithmetic. Second, what determines the problem-size effect (PSE) in cognitive arithmetic? The PSE is the virtually ubiquitous phenomenon that the difficulty of simplearithmetic problems increases as problem size increases. The PSE has been recognized and studied systematically for over 75 years (e.g., Clapp, 1924), but our study was the first to estimate the

Metallic Conduction through Engineered DNA: DNA Nanoelectronic Building Blocks

Abstract: A novel way of engineering DNA molecules involves substituting the imino proton of each base pair with a metal ion to obtain $M$-DNA with altered electronic properties. We report the first direct evidence of metalliclike conduction through $15\ensuremath{\mu}\mathrm{m}$ long $M$-DNA. In contrast, measurements on $B$-DNA give evidence of semiconducting behavior with a few hundred meV band gap at room temperature. The drastic change of $M$-DNA conductivity points to a new degree of freedom in the development of future molecular electronics utilizing DNA, such as creating all-DNA junction devices for use as nanoelectronic building blocks.

A randomized, controlled trial of methotrexate versus placebo in early diffuse scleroderma

Abstract: Objective. Early diffuse scleroderma (systemic sclerosis; SSc) has no proven treatment. This study was undertaken to examine the efficacy of methotrexate (MTX) in improving the skin and other disease parameters in early diffuse SSc. Methods. Seventy-one patients with diffuse SSc of <3 years' duration were enrolled in a multicenter, randomized, placebo-controlled, double-blind trial. Thirty-five patients were treated with MTX and 36 with placebo. Treatment was administered for 12 months. The primary outcome measures were skin score (as determined with 2 different indices) and physician global assessment. Results. At baseline, there were no statistically significant differences in skin scores, carbon monoxide diffusing capacity (DLco), physician global assessment, or other secondary outcome measurements between the 2 treatment groups. At study completion, results slightly favored the MTX group (mean SEM modified Rodnan skin score 21.4 +/- 2.8 in the MTX group versus 26.3 +/- 2.1 in the placebo group [P < 0.17]; UCLA skin score. 8.8 +/- 1.2 in the MTX group versus 11.0 +/- 0.9 in the placebo group [P < 0.15]; DLco in the MTX group 75.7 +/- 4.6 versus 61.8 +/- 3.4 in the placebo group [P < 0.2]). In addition, physician global assessment results favored MTX (P < 0.035), whereas patient global assessment did not differ significantly between groups. When between-group differences for changes in scores from baseline to 12 months were examined using intent-to-treat methodology, MTX appeared to have a favorable effect on skin scores (modified Rodnan score -4.3 in the MTX group versus 1.8 in the placebo group [P < 0.009]; UCLA score -1.2 in the MTX group versus 1.2 in the placebo group [P < 0.02]), but differences in the degree of change in the DLco and physician global assessment were not significant. For the UCLA skin score, these differences in results were not statistically significant after adjustment for baseline differences in sex distribution and steroid use. Dropout rates were similar in the 2 groups. Conclusion. Although results of this trial demonstrated a trend in favor of MTX versus placebo in the treatment of early diffuse SSc, the between-group differences were small and the power to rule out false-negative results was only 50%. Our findings do not provide evidence that MTX is significantly effective in the treatment of early diffuse SSc.

Effects of acetic acid and lactic acid on the growth of Saccharomyces cerevisiae in a minimal medium.

Abstract: Specific growth rates (μ) of two strains of Saccharomyces cerevisiae decreased exponentially (R 2>0.9) as the concentrations of acetic acid or lactic acid were increased in minimal media at 30°C. Moreover, the length of the lag phase of each growth curve (h) increased exponentially as increasing concentrations of acetic or lactic acid were added to the media. The minimum inhibitory concentration (MIC) of acetic acid for yeast growth was 0.6% w/v (100 mM) and that of lactic acid was 2.5% w/v (278 mM) for both strains of yeast. However, acetic acid at concentrations as low as 0.05–0.1% w/v and lactic acid at concentrations of 0.2–0.8% w/v begin to stress the yeasts as seen by reduced growth rates and decreased rates of glucose consumption and ethanol production as the concentration of acetic or lactic acid in the media was raised. In the presence of increasing acetic acid, all the glucose in the medium was eventually consumed even though the rates of consumption differed. However, this was not observed in the presence of increasing lactic acid where glucose consumption was extremely protracted even at a concentration of 0.6% w/v (66 mM). A response surface central composite design was used to evaluate the interaction between acetic and lactic acids on the specific growth rate of both yeast strains at 30C. The data were analysed using the General Linear Models (GLM) procedure. From the analysis, the interaction between acetic acid and lactic acid was statistically significant (P≤0.001), i.e., the inhibitory effect of the two acids present together in a medium is highly synergistic. Journal of Industrial Microbiology & Biotechnology (2001) 26, 171–177.

Mutant Prevention Concentrations of Fluoroquinolones for Clinical Isolates of Streptococcus pneumoniae

Abstract: The mutant prevention concentration (MPC) represents a threshold above which the selective proliferation of resistant mutants is expected to occur only rarely. A provisional MPC (MPC pr ) was defined and measured for five fluoroquinolones with clinical isolates of Streptococcus pneumoniae . Based on their potential for restricting the selection of resistant mutants, the five fluoroquinolones, in descending order, were found to be moxifloxacin > trovafloxacin > gatifloxacin > grepafloxacin > levofloxacin. For several compounds, 90% of about 90 clinical isolates that lacked a known resistance mutation had a value of MPC pr that was close to or below the serum levels that could be attained with a dosing regimen recommended by the manufacturers. Since MPC pr overestimates MPC, these data identify moxifloxacin and gatifloxacin as good candidates for determining whether MPC pr can be used as a guide for choosing and eventually administering fluoroquinolones to significantly reduce the development of resistance.

Integrating Western and Aboriginal Sciences: Cross-Cultural Science Teaching

Abstract: The article addresses issues of social power and privilege experienced by Aboriginal students in science classrooms. First, I present a rationale for a cross-cultural science education dedicated to all students making personal meaning out of their science classrooms. Then I describe a practical research and development project, “Rekindling Traditions: Cross-Cultural Science & Technology Units,” that modestly illustrates cross-cultural science teaching for years 6–11, in which Western and Aboriginal sciences are integrated. This integration is discussed in terms of the “Rekindling Traditions” units, including the assessment of students.

The Importance of Awareness for Team Cognition in Distributed Collaboration

Abstract: Although the phrase team cognition suggests something that happens inside people’s heads, teams are very much situated in the real world, and there are a number of things that have to happen out in that world for teams to be able to think and work together. This is not just spoken communication. Depending on the circumstances, effective team cognition includes things like using environmental cues to establish a common ground of understanding, seeing who is around and what they are doing, monitoring the state of artefacts in a shared work setting, noticing other people’s gestures and what they are referring to, and so on (Clark, 1996; Hutchins, 1996).

Trigonellafoenum graecum (fenugreek) seed powder improves glucose homeostasis in alloxan diabetic rat tissues by reversing the altered glycolytic, gluconeogenic and lipogenic enzymes.

Abstract: Trigonella foenum graecum (fenugreek) seed powder has been suggested to have potential antidiabetic effects. The effect of oral administration of Trigonella whole seed powder (5% in the diet) for 21 days on glycolytic, gluconeogenic and NADPlinked lipogenic enzymes were studied in liver and kidney tissues of alloxan-induced diabetic Wistar rats. Diabetic rats were characterised by a 4fold higher blood glucose level and a 0.7fold lower body weight compared to normal controls. The activities of the glycolytic enzymes were significantly lower in the diabetic liver and higher in the diabetic kidney. The activities of gluconeogenic enzymes were higher in both liver and kidney during diabetes, however the activities of the lipogenic enzymes were decreased in both tissues during diabetes. Trigonella seed powder treatment to diabetic rats for 21 days brought down the elevated fasting blood glucose levels to control levels. The altered enzyme activities were significantly restored to control values in both the liver and kidney after Trigonella seed powder treatment. The therapeutic role of Trigonella seed powder in type1 diabetes as exemplified in this study can be attributed to the change of glucose and lipid metabolising enzyme activities to normal values, thus stabilizing glucose homeostasis in the liver and kidney. These biochemical effects exerted by Trigonella seeds make it a possible new therapeutic in type1 diabetes.

Non-Hodgkin’s Lymphoma and Specific Pesticide Exposures in Men: Cross-Canada Study of Pesticides and Health

Abstract: Our objective in the study was to investigate the putative associations of specific pesticides with non-Hodgkin's Lymphoma [NHL; International Classification of Diseases, version 9 (ICD-9) 200, 202]. We conducted a Canadian multicenter population-based incident, case (n = 517)-control (n = 1506) study among men in a diversity of occupations using an initial postal questionnaire followed by a telephone interview for those reporting pesticide exposure of 10 h/year or more, and a 15% random sample of the remainder. Adjusted odds ratios (ORs) were computed using conditional logistic regression stratified by the matching variables of age and province of residence, and subsequently adjusted for statistically significant medical variables (history of measles, mumps, cancer, allergy desensitization treatment, and a positive history of cancer in first-degree relatives). We found that among major chemical classes of herbicides, the risk of NHL was statistically significantly increased by exposure to phenoxyherbicides [OR, 1.38; 95% confidence interval (CI), 1.06-1.81] and to dicamba (OR, 1.88; 95% CI, 1.32-2.68). Exposure to carbamate (OR, 1.92; 95% CI, 1.22-3.04) and to organophosphorus insecticides (OR, 1.73; 95% CI, 1.27-2.36), amide fungicides, and the fumigant carbon tetrachloride (OR, 2.42; 95% CI, 1.19-5.14) statistically significantly increased risk. Among individual compounds, in multivariate analyses, the risk of NHL was statistically significantly increased by exposure to the herbicides 2,4-dichlorophenoxyacetic acid (2,4-D; OR, 1.32; 95% CI, 1.01-1.73), mecoprop (OR, 2.33; 95% CI, 1.58-3.44), and dicamba (OR, 1.68; 95% CI, 1.00-2.81); to the insecticides malathion (OR, 1.83; 95% CI, 1.31-2.55), 1,1,1-trichloro-2,2-bis (4-chlorophenyl) ethane (DDT), carbaryl (OR, 2.11; 95% CI, 1.21-3.69), aldrin, and lindane; and to the fungicides captan and sulfur compounds. In additional multivariate models, which included exposure to other major chemical classes or individual pesticides, personal antecedent cancer, a history of cancer among first-degree relatives, and exposure to mixtures containing dicamba (OR, 1.96; 95% CI, 1.40-2.75) or to mecoprop (OR, 2.22; 95% CI, 1.49-3.29) and to aldrin (OR, 3.42; 95% CI, 1.18-9.95) were significant independent predictors of an increased risk for NHL, whereas a personal history of measles and of allergy desensitization treatments lowered the risk. We concluded that NHL was associated with specific pesticides after adjustment for other independent predictors.

A molecular phylogeny of the grass subfamily Panicoideae (Poaceae) shows multiple origins of C4 photosynthesis

Abstract: DNA sequence data from the chloroplast gene ndhF were analyzed to estimate the phylogeny of the subfamily Panicoideae, with emphasis on the tribe Paniceae. Our data suggest that the subfamily is divided into three strongly supported clades, corresponding to groups with largely identical base chromosome numbers. Relationships among the three clades are unclear. In unweighted parsimony analyses, the two major clades with x = 10 (Andropogoneae and x = 10 Paniceae) are weakly supported as sister taxa. The third large clade corresponds to x = 9 Paniceae. In analyses under implied weight, the two clades of Paniceae are sisters, making the tribe monophyletic. Neither resolution is strongly supported.Our molecular phylogenies are not congruent with previous classifications of tribes or subtribes. Based on this sample of species, we infer that C(4) photosynthesis has evolved independently several times, although a single origin with multiple reversals and several reacquisitions is only slightly less parsimonious. The phosphoenol pyruvate carboxykinase (PCK) subtype of C(4) photosynthesis has evolved only once, as has the NAD-malic enzyme (ME) subtype; all other origins are NADP-ME. Inflorescence bristles are apparently homologous in the genera Setaria and Pennisetum, contrary to opinions of most previous authors. Some genera, such as Digitaria, Echinochloa, and Homolepis are supported as monophyletic. The large genus Paspalum is shown to be paraphyletic, with Thrasya derived from within it. As expected, Panicum is polyphyletic, with lineages derived from multiple ancestors across the tree. Panicum subg. Panicum is monophyletic. Panicum subg. Dichanthelium, subg. Agrostoides, and subg. Phanopyrum are unrelated to each other, and none is monophyletic. Only Panicum subg. Dichanthelium sect. Dichanthelium, represented by P. sabulorum and P. koolauense, is monophyletic. Panicum subg. Megathyrsus, a monotypic subgenus including only the species P. maximum, is better placed in Urochloa, as suggested by other authors.

Reliability/Cost Implications of PV and Wind Energy Utilization in Small Isolated Power Systems

Abstract: The application of renewable energy in electric power systems is growing rapidly due to enhanced public concerns for adverse environmental impacts and escalation in energy costs associated with the use of conventional energy sources. Photovoltaics and wind energy sources are being increasingly recognized as cost-effective generation sources in small isolated power systems primarily supplied by costly diesel fuel. The utilization of these energy sources can significantly reduce the system fuel costs but can also have considerable impact on the system reliability. A realistic cost/reliability analysis requires evaluation models that can recognize the highly erratic nature of these energy sources while maintaining the chronology and interdependence of the random variables inherent in them. This paper presents a simulation method that provides objective indicators to help system planners decide on appropriate installation sites, operating policies, and selection of energy types, sizes, and mixes in capacity expansion when utilizing PV and wind energy in small isolated systems.

Students' ease in crossing cultural borders into school science

Abstract: The purpose of this article is to fine-tune a grounded-theory scheme originally proposed in this journal by Costa (1995). She categorized students according to the ease with which they succeed in school science; an ease related to the similarity between their life-world culture and

Microclimate of tree cavity nests: is it important for reproductive success in northern flickers?

Abstract: I measured structural characteristics of 160 Northern Flicker (Colaptes auratus) nests at Riske Creek, British Columbia, and placed electronic data-loggers in a subsample of 86 nests to record internal temperatures after the flickers completed nesting. Using multiple regression, I found that the best predictors of a variety of nest-cavity temperature variables were tree health, diameter of the tree at cavity height, and orientation of the cavity. Small and dead trees showed the most extreme (maximum and minimum) temperatures during the day, but, on average, were the coldest nests from the perspective of incubation. South-facing cavities reached the highest temperatures during the day, and the orientation of natural cavities was also biased towards the south. I predicted that cold nests would be energetically expensive for adults and nestlings, and found that clutch size was positively correlated with mean cavity temperature. However, there did not appear to be any relationship among nest temperat...

CpG motif identification for veterinary and laboratory species demonstrates that sequence recognition is highly conserved.

Abstract: Oligodinucleotides containing CpG motifs stimulate vertebrate immune cells in vitro, have proven efficacy in murine disease models and are currently being tested in human clinical trials as therapies for cancer, allergy, and infectious disease. As there are no known immunostimulatory motifs for veterinary species, the potential of CpG DNA as a veterinary pharmaceutical has not been investigated. Here, optimal CpG motifs for seven veterinary and three laboratory species are described. The preferential recognition of a GTCGTT motif was strongly conserved across two vertebrate phyla, although a GACGTT motif was optimal for inbred strains of mice and rabbits. In a subsequent adjuvanticity trial, the in vitro screening methodology was validated in sheep, representing the first demonstration of CpG DNA efficacy in a veterinary species. These results should provide candidate immunostimulant and therapeutic drugs for veterinary use and enable the testing of CpG DNA in large animal models of human disease.

Baseline studies of the clay minerals society source clays: chemical analyses of major elements

Abstract: Chemical analysis is an essential step to establish the nature of minerals (Newman, 1987). The techniques used in rock and mineral analyses are generally valid for the analyses of clays. Additional information from other analytical techniques, which are mentioned here, is needed for accurate interpretation of the chemical analysis results of major elements (Gabis, 1979). In traditional chemical analyses, the aim is to obtain accurate analyses for all elements present in the sample, in such a way that the sum of elements expressed as oxides, including hydration and structural water, approaches the sample weight as closely as possible. The following elements are essential for the calculation of structural formulae of most clay minerals and silicates: Si, Al, Fe3+, Fe2+, Mg, Ti, Mn (in special cases), P, Ca, Na, K and H2O evolved below 105°C (H2O+) and between 105–1000°C (H2O+). For some minerals, additional determinations, such as for F and Li, may be needed for the calculation of the composition of clay minerals. Methods used to determine the chemical composition, for both major and minor elements, are described elsewhere (Jackson, 1979; Lim and Jackson, 1982; Laird et al., 1989; Amonette and Zelazny, 1994). For minor or trace elements of the Source Clays, see Elzea Kogel and Lewis (2001). Despite the progress made in science, and the increased accuracy which can be obtained from very sophisticated instruments, total …

DNA postreplication repair and mutagenesis in Saccharomyces cerevisiae.

Abstract: DNA postreplication repair (PRR) is defined as an activity to convert DNA damage-induced single-stranded gaps into large molecular weight DNA without actually removing the replication-blocking lesions. In bacteria such as Escherichia coli, this activity requires RecA and the RecA-mediated SOS response and is accomplished by recombination and mutagenic translesion DNA synthesis. Eukaryotic cells appear to share similar DNA damage tolerance pathways; however, some enzymes required for PRR in eukaryotes are rather different from those of prokaryotes. In the yeast Saccharomyces cerevisiae, PRR is centrally controlled by RAD6 and RAD18, whose products form a stable complex with single-stranded DNA-binding, ATPase and ubiquitin-conjugating activities. PRR can be further divided into translesion DNA synthesis and error-free modes, the exact molecular events of which are largely unknown. This error-free PRR is analogous to DNA damage-avoidance as defined in mammalian cells, which relies on recombination processes. Two possible mechanisms by which recombination participate in PRR to resolve the stalled replication folk are discussed. Recombination and PRR are also genetically regulated by a DNA helicase and are coupled to the cell-cycle. The PRR processes appear to be highly conserved within eukaryotes, from yeast to human.

Flexible fixture design and automation: Review, issues and future directions

Abstract: The cost of designing and fabricating fixtures can amount to 10-20% of the total manufacturing system costs. To reduce manufacturing costs, a fixture system is designed to be competent in fixturing as many workpieces as possible. In mass volume production, this can be achieved by fixturing a large quantity of the same kind of workpieces. In low-to-medium volume production, however, improvement of the flexibility of fixture systems becomes a favourable way to reduce the unit cost of product. This paper summarizes the latest studies in the field of flexible fixture design and automation. First, a brief introduction is given on this research area. Secondly, taxonomy of flexible fixture design activities is presented. Thirdly, the flexibility strategies based on the existing flexible fixture systems are discussed. Fourthly, the contributions on design methodologies and verifications are examined. Fifthly, advances on computer-aided design and see-up systems are summarized. Finally, some prospective research t...

The influence of osteoporotic fractures on health-related quality of life in community-dwelling men and women across Canada.

Abstract: Health-related quality of life (HRQL) was examined in relation to prevalent fractures in 4816 community-dwelling Canadian men and women 50 years and older participating in the Canadian Multicentre Osteoporosis Study (CaMos). Fractures were of three categories: clinically recognized main fractures, subclinical vertebral fractures and fractures at other sites. Main fractures were divided and analyzed at the hip, spine, wrist/forearm, pelvis and rib sites. Baseline assessments of anthropometric data, medical history, therapeutic drug use, spinal radiographs and prevalent fractures were obtained from all participants. The SF-36 instrument was used as a tool to measure HRQL. A total of 652 (13.5%) main fractures were reported. Results indicated that hip, spine, wrist/forearm, pelvis and rib fractures had occurred in 78 (1.6%), 40 (0.8%), 390 (8.1%), 19 (0.4%) and 125 (2.6%) individuals, respectively (subjects may have had more than one main fracture). Subjects who had experienced a main prevalent fracture had lower HRQL scores compared with non-fractured participants. The largest differences were observed in the physical functioning (−4.0; 95% confidence intervals (CI): −6.0, −2.0) and role-physical functioning domains (−5.8; 95% CI: −9.5, −2.2). In women, the physical functioning domain was most influenced by hip (−14.9%; 95% CI: −20.9, −9.0) and pelvis (−18.1; 95% CI: −27.6, −8.6) fractures. In men, the role-physical domain was most affected by hip fractures (−35.7; 95% CI: −60.4, −11.1). Subjects who experienced subclinical vertebral fractures had lower HRQL scores than those without prevalent fractures. In conclusion, HRQL was lower in the physical functioning domain in women and the role-physical domain in men who sustained main fractures at the hip. Subclinical vertebral fractures exerted a moderate effect on HRQL.

QTL analysis of agronomic traits in barley based on the doubled haploid progeny of two elite North American varieties representing different germplasm groups

Abstract: A better understanding of the genetics of complex traits, such as yield, may be achieved by using molecular tools. This study was conducted to estimate the number, genome location, effect and allele phase of QTLs determining agronomic traits in the two North American malting barley (Hordeum vulgare L.) quality variety standards. Using a doubled haploid population of 140 lines from the cross of two-rowed Harrington×six-rowed Morex, agronomic phenotypic data sets from nine environments, and a 107-marker linkage map, we performed QTL analyses using simple interval mapping and simplified composite interval mapping procedures. Thirty-five QTLs were associated, either across environments or in individual environments, with five grain and agronomic traits (yield, kernel plumpness, test weight, heading date, and plant height). Significant QTL×environment interaction was detected for all traits. These interactions resulted from both changes in the magnitude of response and changes in the sign of the allelic effect. QTLs for multiple traits were coincident. The vrs1 locus on chromosome 2 (2H), which determines inflorescence row type, was coincident with the largest-effect QTL determining four traits (yield, kernel plumpness, test weight, and plant height). QTL analyses were also conducted separately for each sub-population (six-rowed and two-rowed). Seven new QTLs were detected in the sub-populations. Positive transgressive segregants were found for all traits, but they were more prevalent in the six-rowed sub-population.QTL analysis should be useful for identifying candidate genes and introgressing favorable alleles between germplasm groups.

Minimizing bandwidth requirements for on-demand data delivery

Abstract: Two recent techniques for multicast or broadcast delivery of streaming media can provide immediate service to each client request, yet achieve considerable client stream sharing which leads to significant server and network bandwidth savings. The paper considers: 1) how well these recently proposed techniques perform relative to each other and 2) whether there are new practical delivery techniques that can achieve better bandwidth savings than the previous techniques over a wide range of client request rates. The principal results are as follows: First, the recent partitioned dynamic skyscraper technique is adapted to provide immediate service to each client request more simply and directly than the original dynamic skyscraper method. Second, at moderate to high client request rates, the dynamic skyscraper method has required server bandwidth that is significantly lower than the recent optimized stream tapping/patching/controlled multicast technique. Third, the minimum required server bandwidth for any delivery technique that provides immediate real-time delivery to clients increases logarithmically (with constant factor equal to one) as a function of the client request arrival rate. Furthermore, it is (theoretically) possible to achieve very close to the minimum required server bandwidth if client receive bandwidth is equal to two times the data streaming rate and client storage capacity is sufficient for buffering data from shared streams. Finally, we propose a new practical delivery technique, called hierarchical multicast stream merging (HMSM), which has a required server bandwidth that is lower than the partitioned dynamic skyscraper and is reasonably close to the minimum achievable required server bandwidth over a wide range of client request rates.

F.I.M. Craik, & T.A. Salthouse (Eds.) The Handbook of Aging and Cognition (2nd ed.). Mahwah, NJ: Lawrence Erlbaum, 2000.

Abstract: La nouvelle version attendue du Handbook of Aging and Cognition presente un survol complet et opportun des principaux themes du vieillissement cognitif. Tour a tour, les chapitres decrivent le secteur du cerveau responsable des changements de la fonction cognitive, les consequences de la deterioration perceptive, passent en revue les changements de l'attention en fonction de l'âge, de la memoire et des aptitudes de langage, presentent un apercu des questions de methodologie et un debat sur la cognition sociale et appliquee. Cette deuxieme edition depasse la simple mise a jour; en fait, son contenu presente peu de repetitions, et, sauf dans le cas des deux redacteurs en chef, les auteurs ne se recoupent pas. En outre, ony trouve des chapitres qui resument des themes relativement nouveaux dans le domaine, notamment un chapitre sur l'emotion et la cognition et un autre sur le fonctionnement cognitif chez les gens tres âges. Ces deux chapitres refletent l'interet actuelpour ces themes importants et interessants. Bien que le livre ne contienne pas de chapitre traitant de sujets cliniques, il fait a maintes reprises reference a des situations cliniques frequentes qui ont des repercussions sur le fonctionnement superieur du cerveau et presentent des rapprochements utiles avec les changements normaux relies a l'age.Ce livre s'adresse aux chercheurs et aux specialistes de la gerontologie cognitive. De plus, il constitue une source d'information utile et une excellente introduction pour les etudiants de cycle superieur et pour ceux qui terminent leur premier cycle. Il saura grandement interesser ceux qui travaillent aupres des aine(e)s et qui veulent comprendre le fonctionnement cognitif normal relie a l'âge. Toutefois, les lecteurs de cette nouvelle edition qui possedent des notions de fonctionnement cognitif et de neuropsychologie tireront un plus grand profit de leur lecture. Une grande partie du materiel presente reflete la presence grandissante de la science cognitive et son interrelation avec les disciplines connexes. Cette nouvelle edition nous rappelle que lesprocessus cognitifs de base n'ont plus a etre examines isolement et qu'on les saisit plus clairement si on les rapproche de leurs fondements biologiques et de contextes sociaux significatifs.