A study of current meter observations of the semidiurnal baroclinic tide of the western North Atlantic,

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Earth and Planetary Science, 1972.Includes bibliographical references (leaves 96-98).by Ronald R. Regal.M.S

Weibull Methods for Testing Individual Group Performance Models

1 online resource (PDF, 24 pages

Effects of Two (Diptera: Culicidae) Mosquito Control Agents on Growth and Reproduction of Red-Winged Blackbirds (Agelaius phoeniceus)

We compared red-winged blackbird (Agelaius phoeniceus) reproductive success and nestling growth in 1988 in 10 wetland site treated with methoprene and 10 sites treated with Bacillus thuringiensis israelensis (Bti) to 30 sites that had never received any mosquito (Diptera: culicidae) control treatment. No differences were detected between reference and treatment sites for clutch size, egg volume, growth rates, or fledge weight. The probability that an egg survived to the nestling stage was greater in methoprene-treated than reference sites. No other differences were detected among sites for reproductive success estimated using the Mayfield method. We conclude that treatment of the wetlands with methoprene or Bti did not directly or indirectly affect red-winged blackbird growth or reproduction within the first two years after treatment

Persistent Effects of Herbaceous Species on the Infectious Lethality of Soil for Conifer Seedlings

Seeds of the coniferous trees Abies balsamea, Picea mariana, and Pinus strobus were sown in the laboratory in two soils taken from ground‐layer patches differing in species composition, one of which was dominated by Aegopodium podagraria (goutweed). This permitted inference whether herbaceous species may affect the favorableness of the soil for establishment of these trees. Weibull distributions were fitted to the time course of aggregate seedling emergence and post-emergence mortality, enabling seedling lifespan to be inferred without monitoring of each individual. A higher percentage of Abies seeds developed into emerged seedlings in the goutweed soil, likely because of less preemergence mortality incited by pathogens. Picea and Pinus emergence percentages were similar in both soils. Most emerged seedlings died within weeks, with symptoms of diseases incited by soil‐ or seed‐borne fungi. Although the timing of seedling emergence did not differ between soils, seedlings died more quickly on the goutweed soil, largely because of a faster development of post‐emergence damping‐off. Total post-emergence mortality of Picea and Pinus was greater on the goutweed soil. The relative frequencies of the several symptoms exhibited by dying seedlings varied between the two soils, suggesting that the ground‐layer species differentially affected the microbial community’s composition or interactions with the seedlings. Symptom frequencies differed among tree species. Local spatial variation in herbaceous species composition appeared to produce patchy infectious lethality of soil for tree seedlings, an indirect effect that was observed after the herbaceous plants had been removed

Breeding Bird Communities Across an Upland Disturbance Gradient in the Western Lake Superior Region

The coastal region of western Lake Superior to examine relationships to human land use. Eighty-four species were detected and 50 were abundant enough to be included in data analysis. Monotonic quadratic regression models were constructed for these 50 species by using species counts as the dependent variable and the proportion of human conversion of the landscape (residential, agriculture, and commercial/industrial land uses) within each study area as the independent variable. Twenty-seven bird species had significant regressions (P < 0.05), 18 of which generally avoided areas developed by humans and 9 of which were attracted to development. De-trended correspondence analysis using counts of these 27 bird species was used to investigate multivariate, community responses to development. The first DCA axis was interpreted as a gradient from urban avoiding to urban exploiting bird species and was strongly correlated with land cover variables related to human development. Our results advance the idea that breeding bird communities can be used as indicators of ecological condition and can diagnose potential causes for changes in these conditions. Further, our study points out the usefulness of bird monitoring data in regional planning efforts that incorporate goals for maintaining native biological diversity

Autosomal recessive cerebellar ataxia caused by mutations in the PEX2 gene

<p>Abstract</p> <p>Objective</p> <p>To expand the spectrum of genetic causes of autosomal recessive cerebellar ataxia (ARCA).</p> <p>Case report</p> <p>Two brothers are described who developed progressive cerebellar ataxia at 3 1/2 and 18 years, respectively. After ruling out known common genetic causes of ARCA, analysis of blood peroxisomal markers strongly suggested a peroxisomal biogenesis disorder. Sequencing of candidate <it>PEX </it>genes revealed a homozygous c.865_866insA mutation in the <it>PEX2 </it>gene leading to a frameshift 17 codons upstream of the stop codon. <it>PEX </it>gene mutations usually result in a severe neurological phenotype (Zellweger spectrum disorders).</p> <p>Conclusions</p> <p>Genetic screening of PEX2 and other PEX genes involved in peroxisomal biogenesis is warranted in children and adults with ARCA.</p

Burnout among surgeons before and during the SARS-CoV-2 pandemic: an international survey

Background: SARS-CoV-2 pandemic has had many significant impacts within the surgical realm, and surgeons have been obligated to reconsider almost every aspect of daily clinical practice. Methods: This is a cross-sectional study reported in compliance with the CHERRIES guidelines and conducted through an online platform from June 14th to July 15th, 2020. The primary outcome was the burden of burnout during the pandemic indicated by the validated Shirom-Melamed Burnout Measure. Results: Nine hundred fifty-four surgeons completed the survey. The median length of practice was 10&nbsp;years; 78.2% included were male with a median age of 37&nbsp;years old, 39.5% were consultants, 68.9% were general surgeons, and 55.7% were affiliated with an academic institution. Overall, there was a significant increase in the mean burnout score during the pandemic; longer years of practice and older age were significantly associated with less burnout. There were significant reductions in the median number of outpatient visits, operated cases, on-call hours, emergency visits, and research work, so, 48.2% of respondents felt that the training resources were insufficient. The majority (81.3%) of respondents reported that their hospitals were included in the management of COVID-19, 66.5% felt their roles had been minimized; 41% were asked to assist in non-surgical medical practices, and 37.6% of respondents were included in COVID-19 management. Conclusions: There was a significant burnout among trainees. Almost all aspects of clinical and research activities were affected with a significant reduction in the volume of research, outpatient clinic visits, surgical procedures, on-call hours, and emergency cases hindering the training. Trial registration: The study was registered on clicaltrials.gov "NCT04433286" on 16/06/2020

Likelihood methods for testing group problem solving models with censored data

maximum likelihood, goodness of fit tests,