Demography, Breeding Biology and Predation of Willow Ptarmigan at Anderson River Delta, Northwest Territories

Observations on the willow ptarmigan (Lagopus lagopus albus) were made during the breeding season from 1958 to 1985 at the Anderson River delta, N.W.T. Numbers of territorial males on a 65 ha study area have fluctuated between 7 and 28 over this time, with numbers peaking in 1961-62, 1969 and 1980. Peaks in ptarmigan numbers appear to be fairly synchronous over a large geographical area. Large flocks of males were observed in some years. In 1978, these males, mainly yearlings, had similar wing lengths to, but weighed slightly more than territorial males. There appeared to be shortage of hens in 1978, possibly caused by differential mortality during the winter. Mean clutch size ranged from 8.7 to 10.4 and mean number of fledged chicks per brood ranged from 6.3 to 6.9. Within North America clutch size of willow ptarmigan does not appear to increase with increasing latitude. As in other localities, raptors and foxes appeared to be the main predators of ptarmigan. More males than females were killed on the breeding area, but this could have been because more males were present.Key words: willow ptarmigan, Northwest Territories, breeding, clutch size, demography, predationMots clés: lagopède des saules, Territoires du Nord-Ouest, nidification, taille de la couvée, démographie, prédatio

Effects of Seismic Lines on the Abundance of Breeding Birds in the Kendall Island Bird Sanctuary, Northwest Territories, Canada

Current plans to increase oil and gas exploration and extraction in the Canadian Arctic include development in the Kendall Island Bird Sanctuary, Northwest Territories. Various studies have shown impacts of seismic lines on vegetation, but the effects on bird abundance in the Arctic are poorly known. We evaluated the impact of new (0.5–1.5 years old) and old (10–35 years old) visible seismic lines within the sanctuary on the abundance of breeding passerines (savannah sparrow, Passerculus sandwichensis; Lapland longspur, Calcarius lapponicus; common redpoll, Carduelis flammea; American tree sparrow, Spizella arborea; and red-necked phalarope, Phalaropus lobatus) in upland tundra, low-centre polygon, and sedge/willow habitats. Along new seismic lines, effects on abundance were not statistically significant for most groups of birds, although the trend in most habitats was for more birds on reference transects than on seismic lines. Significant impacts were found for passerines grouped in upland tundra and for savannah sparrow in sedge/willow. The latter effect (possibly due to standing water along the line) was not significant the following year. Along old seismic lines, abundance of passerines was lower than on reference transects in upland tundra and low-centre polygon habitat, except for Lapland longspurs in upland tundra. Lines created 10–30 years ago have persistent vegetative changes and this appears to have reduced bird abundance. Although we did not plot individual territories, birds were seen crossing the seismic lines and sometimes perched on them, suggesting that they were not avoiding the lines altogether. Instead, these birds may have increased territory size to compensate for vegetative changes along the lines.Les plans actuels visant l’intensification des travaux d’exploration et d’extraction pétrolière et gazière dans l’Arctique canadien visent la mise en valeur du refuge d’oiseaux de l’île Kendall, dans les Territoires du Nord-Ouest. Même si diverses études ont permis de démontrer les effets des profils sismiques sur la végétation, les effets de ces profils sur l’abondance d’oiseaux dans l’Arctique sont méconnus. Au sein du refuge, nous avons évalué l’incidence des nouveaux (de 0,5 à 1,5 an) et anciens (de 10 à 35 ans) profils sismiques visibles sur l’abondance des passériformes nicheurs (bruant des prés, Passerculus sandwichensis; bruant lapon, Calcarius lapponicus; sizerin flammé, Carduelis flammea; bruant hudsonien, Spizella arborea et phalarope à bec large, Phalaropus lobatus) dans la toundra supérieure, le polygone à centre concave et les habitats de laiche et de saule. Le long des nouveaux profils sismiques, les effets enregistrés sur l’abondance n’étaient pas statistiquement importants pour la plupart des groupes d’oiseaux, bien que dans la plupart des habitats, la tendance se traduit par la présence d’un plus grand nombre d’oiseaux dans les transects de référence que dans les profils sismiques. Les effets étaient importants dans le cas des passériformes regroupés dans la toundra supérieure ainsi que dans le cas du bruant des prés évoluant dans l’habitat de laiche et de saule. Ce dernier effet (qui pourrait être attribuable à l’eau stagnante le long du profil) n’était pas considérable l’année suivante. Le long des anciens profils sismiques, les passériformes se trouvaient en moins grande abondance que dans l’habitat du transect de référence de la toundra supérieure et du polygone à centre concave, sauf dans le cas du bruant lapon de la toundra supérieure. Les profils dont l’existence remonte à 10 à 30 ans sont caractérisés par des changements durables du point de vue de la végétation, et cela semble avoir eu pour effet de diminuer l’abondance d’oiseaux. Même si nous n’avons pas tracé de territoires individuels, nous avons aperçu des oiseaux en train de traverser les profils sismiques, où ils se perchaient même parfois, ce qui laisse entrevoir qu’ils n’évitaient pas les profils. Au lieu, il se peut que ces oiseaux disposent d’un territoire plus grand, ce qui compenserait pour les changements végétatifs dénotés le long des profils

Using the Stages of Change Model to Choose an Optimal Health Marketing Target

Background: In the transtheoretical model of behavior change, “stages of change” are defined as Precontemplation (not even thinking about changing), Contemplation, Preparation, Action, and Maintenance (maintaining the behavior change). Marketing principles suggest that efforts should be targeted at persons most likely to “buy the product.” Objectives: To examine the effect of intervening at different stages in populations of smokers, with various numbers of people in each “stage of change.” One type of intervention would increase by 10% the probability of a person moving to the next higher stage of change, such as from Precontemplation to Contemplation. The second type would decrease by 10% the probability of relapsing to the next lower stage, such as from Maintenance to Action, and also of changing from Never Smoker to Smoker. Nine hypothetical interventions were compared with the status quo, to determine which type of intervention would provide the most improvement in population smoking. Methods: Three datasets were used to estimate the probability of moving among the stages of change for smoking. Those probabilities were used to create multi-state life tables, which yielded estimates of the expected number of years the population would spend in each stage of change starting at age 40. We estimated the effect of each hypothetical intervention, and compared the intervention effects. Several initial conditions, time horizons, and criteria for success were examined. Results: A population of 40-year-olds in Precontemplation had a further life expectancy of 36 years, of which 26 would be spent in the Maintenance stage. In a population of former and current smokers, moving more persons from the Action to the Maintenance stage (a form of relapse prevention) decreased the number of years spent smoking more than the any other intervention. In a population of 40-year-olds that included Never Smokers, primary smoking prevention was the most effective. The results varied somewhat by the choice of criterion, the length of follow-up, the initial stage distribution, the data, and the sensitivity analyses. Conclusions: In a population of 40-year-olds, smokers were likely to achieve Maintenance without an intervention. On the population basis, targeting quitters and never-smokers was more effective than targeting current smokers. This finding is supported by some principles of health marketing. Additional research should target younger ages as well as other health behaviors

Differing effects when using phenylephrine and norepinephrine to augment cerebral blood flow after traumatic brain injury in the immature brain

Low cerebral blood flow (CBF) states have been demonstrated in children early after traumatic brain injury (TBI), and have been correlated with poorer outcomes. Cerebral perfusion pressure (CPP) support following severe TBI is commonly implemented to correct cerebral hypoperfusion, but the efficacy of various vasopressors has not been determined. Sixteen 4-week-old female swine underwent nonimpact inertial brain injury in the sagittal plane. Intraparenchymal monitors were placed to measure intracranial pressure (ICP), CBF, brain tissue oxygen tension (PbtO(2)), and cerebral microdialysis 30 min to 6 h post-injury. One hour after injury, animals were randomized to receive either phenylephrine (PE) or norepinephrine (NE) infusions titrated to a CPP >70 mm Hg for 5 h. Animals were euthanized 6 h post-TBI, and brains were fixed and stained to assess regions of cell and axonal injury. After initiation of CPP augmentation with NE or PE infusions, there were no differences in ICP between the groups or over time. Animals receiving NE had higher PbtO(2) than those receiving PE (29.6±10.2 vs. 19.6±6.4 torr at 6 h post-injury, p<0.05). CBF increased similarly in both the NE and PE groups. CPP support with PE resulted in a greater reduction in metabolic crisis than with NE (lactate/pyruvate ratio 16.7±2.4 vs. 42.7±10.2 at 6 h post-injury, p<0.05). Augmentation of CPP to 70 mm Hg with PE resulted in significantly smaller cell injury volumes at 6 h post-injury than CPP support with NE (0.4% vs. 1.4%, p<0.05). Despite similar increases in CBF, CPP support with NE resulted in greater brain tissue oxygenation and hypoxic-ischemic injury than CPP support with PE. Future clinical studies comparing the effectiveness of various vasopressors for CPP support are warranted

Selection of hyperfunctional siRNAs with improved potency and specificity

One critical step in RNA interference (RNAi) experiments is to design small interfering RNAs (siRNAs) that can greatly reduce the expression of the target transcripts, but not of other unintended targets. Although various statistical and computational approaches have been attempted, this remains a challenge facing RNAi researchers. Here, we present a new experimentally validated method for siRNA design. By analyzing public siRNA data and focusing on hyperfunctional siRNAs, we identified a set of sequence features as potency selection criteria to build an siRNA design algorithm with support vector machines. Additional bioinformatics filters were also included in the algorithm to increase RNAi specificity by reducing potential sequence cross-hybridization or microRNA-like effects. Independent validation experiments were performed, which indicated that the newly designed siRNAs have significantly improved performance, and worked effectively even at low concentrations. Furthermore, our cell-based studies demonstrated that the siRNA off-target effects were significantly reduced when the siRNAs were delivered into cells at the 3 nM concentration compared to 30 nM. Thus, the capability of our new design program to select highly potent siRNAs also renders increased RNAi specificity because these siRNAs can be used at a much lower concentration. The siRNA design web server is available at http://www5.appliedbiosystems.com/tools/siDesign/

Effects of antiplatelet therapy on stroke risk by brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases: subgroup analyses of the RESTART randomised, open-label trial

Background Findings from the RESTART trial suggest that starting antiplatelet therapy might reduce the risk of recurrent symptomatic intracerebral haemorrhage compared with avoiding antiplatelet therapy. Brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases (such as cerebral microbleeds) are associated with greater risks of recurrent intracerebral haemorrhage. We did subgroup analyses of the RESTART trial to explore whether these brain imaging features modify the effects of antiplatelet therapy

TGFB1 and TGFBR1 polymorphisms and breast cancer risk in the Nurses' Health Study

Background Transforming growth factor beta 1 (TGFB1) forms a signaling complex with transforming growth factor beta receptors 1 and 2 and has been described as both a tumor suppressor and tumor promoter. Single nucleotide polymorphisms in TGFB1 and a microsatellite in TGFBR1 have been investigated for association with risk of breast cancer, with conflicting results. Methods We examined polymorphisms in the promoter region of the TGFB1 gene as well as the TGFBR1*6A microsatellite in the Nurses\u27 Health Study cohort. Results No overall associations between the L10P polymorphism of TGFB1 or the TGFBR1 microsatellite were detected. However, we observed an inverse association between the -509 C/T polymorphism of TGFB1 (p-trend = 0.04), which was stronger and more significant among women with estrogen receptor positive breast cancer. Conclusion Polymorphisms in the promoter region of TGFB1 are not likely to be associated with large increases in breast cancer risk overall among Caucasian women

Predicting Weight Outcomes in Preadolescence: The Role of Toddlers? Self-regulation Skills and the Temperament Dimension of Pleasure

Objective To investigate the role of toddlers? self-regulation skills and temperament in predicting weight outcomes in preadolescence. Method Participants for this study included 195 children (114 girls) obtained from three different cohorts participating in a larger ongoing longitudinal study. At 2 years of age, participants participated in several laboratory tasks designed to assess their self-regulation abilities, including emotion regulation, sustained attention, and delay of gratification, while parents filled out a temperament questionnaire to assess toddlers? pleasure expression. Height and weight measures were collected when children were 4, 5, 7, and 10 years of age. Children also filled out a body image and eating questionnaire at the 10 year visit. Results Self-regulation skills in toddlers were associated with both BMI development, pediatric obesity, and body image/eating concerns. The temperament dimension of pleasure was also associated with BMI development and pediatric obesity but not body image/eating concerns. Conclusion Self-regulation difficulties across domains as well as temperament based pleasure in toddlers represented significant individual risk factors for the development of pediatric obesity eight years later. Early self-regulation difficulties also contributed to body image and eating concerns that typically accompanied overweight children. The mechanisms by which early self-regulation skills and temperament based pleasure may contribute to the development of pediatric obesity and associated weight concerns are discussed

Silent chromatin at the middle and ends: lessons from yeasts

Eukaryotic centromeres and telomeres are specialized chromosomal regions that share one common characteristic: their underlying DNA sequences are assembled into heritably repressed chromatin. Silent chromatin in budding and fission yeast is composed of fundamentally divergent proteins tat assemble very different chromatin structures. However, the ultimate behaviour of silent chromatin and the pathways that assemble it seem strikingly similar among Saccharomyces cerevisiae (S. cerevisiae), Schizosaccharomyces pombe (S. pombe) and other eukaryotes. Thus, studies in both yeasts have been instrumental in dissecting the mechanisms that establish and maintain silent chromatin in eukaryotes, contributing substantially to our understanding of epigenetic processes. In this review, we discuss current models for the generation of heterochromatic domains at centromeres and telomeres in the two yeast species

Common and rare variant association analyses in amyotrophic lateral sclerosis identify 15 risk loci with distinct genetic architectures and neuron-specific biology

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease with a lifetime risk of one in 350 people and an unmet need for disease-modifying therapies. We conducted a cross-ancestry genome-wide association study (GWAS) including 29,612 patients with ALS and 122,656 controls, which identified 15 risk loci. When combined with 8,953 individuals with whole-genome sequencing (6,538 patients, 2,415 controls) and a large cortex-derived expression quantitative trait locus (eQTL) dataset (MetaBrain), analyses revealed locus-specific genetic architectures in which we prioritized genes either through rare variants, short tandem repeats or regulatory effects. ALS-associated risk loci were shared with multiple traits within the neurodegenerative spectrum but with distinct enrichment patterns across brain regions and cell types. Of the environmental and lifestyle risk factors obtained from the literature, Mendelian randomization analyses indicated a causal role for high cholesterol levels. The combination of all ALS-associated signals reveals a role for perturbations in vesicle-mediated transport and autophagy and provides evidence for cell-autonomous disease initiation in glutamatergic neurons. A cross-ancestry genome-wide association meta-analysis of amyotrophic lateral sclerosis (ALS) including 29,612 patients with ALS and 122,656 controls identifies 15 risk loci with distinct genetic architectures and neuron-specific biology