605 research outputs found

    Mine Safety Legislation: A History of Neglect

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    Resources in Europe of interest to mathematics teachers,

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    Thesis (M.A.)--Boston University. This thesis was written in conjunction with Dennis J. Roberts, Mary Lee McLaughlin and Robert F. Pierce.Statement of the problem: It is the purpose of this thesis to formulate plans for a guided tour throughout Western Europe for secondary-school teachers with emphasis on present and past mathematical and allied science contributions. This study will serve as an answer to four fundamental questions: 1. What are the resources available in Europe of value to mathematics teachers? 2. From the standpoint of marginal utility, which of these would be the most important? 3. where are they to be found? 4. How long would it take to see each of them profitably in a limited amount of time? [TRUNCATED

    SHIVERING BY CAPTIVE MOOSE INFESTED WITH WINTER TICKS

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    Occurence and rate of shivering were measured to assess thermoregulatory responses of captive moose (Alces alces) infested with winter ticks (Dermacentor albipictus). Shivering was observed on 47 occasions in 5 of 8 infested moose calves from October to April; in contrast, 4 moose calves not infested with winter ticks did not shiver under identical weather conditions. Only 5 shivering bouts occurred from October to March, all on a single day. The other 42 shivering bouts occurred in April with bouts lasting 1–103 min. During the April bouts, ambient temperature was 1– 4 °C (42 of 42), maximum wind speed was ≤12 km/h (38 of 42), and it was raining (30 of 42). Shivering was associated with 23–44% hair loss in April, but not during cold weather in mid-winter despite 5–10% hair loss in March. Maintaining stable core body temperature during late winter-early spring could compromise the energetic balance of wild free-ranging moose with extensive hair loss and abundant ticks, in conditions equivalent to or worse than measured in this study

    The supraclavius muscle is a novel muscular anomaly observed in two cases of thoracic outlet syndrome

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    Various anomalous muscles and fibrofascial structures have been described in relation to the anatomy of thoracic outlet syndrome. We describe two patients with a previously undescribed muscle anomaly, which originated laterally near the trapezius muscle, coursed across the supraclavicular space deep to the scalene fat pad, and attached obliquely to the superior undersurface of the medial clavicle, which we have termed the “supraclavius” muscle. The significance of the supraclavius muscle is unknown, but its occurrence in patients with thoracic outlet syndrome indicates that it can be associated with narrowing of the anatomic space adjacent to the neurovascular structures

    BODY TEMPERATURE OF CAPTIVE MOOSE INFESTED WITH WINTER TICKS

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    Eighteen captive moose calves (Alces alces) were divided into 3 groups that represented 3 levels of winter tick (Dermacentor albipictus) infestation (0, 21,000, and 42,000 ticks). A total of 321 body temperatures (Tb) were taken on 19 occasions between late November and mid-April. The mean Tb of individuals was 38.2 ± 0.4 °C, ranging from 38.0–38.3 °C, and was not different among the control and infested groups (P = 0.816), but varied temporally (P < 0.001) with a significant interaction effect between treatment and time (P = 0.041); these temporal differences are unexplained. The Tbs measured in this study are some of the lowest reported for moose and presumably represent the resting Tb of free-ranging moose, more so than those measured after pursuit, restraint, and/or immobilization during capture. This was not a definitive test of the effects of tick infestation on wild moose because the captive moose consumed a high quality diet throughout winter and surprisingly low numbers of ticks remained on the animals in mid-April

    Polymorphic Variation of Genes in the Fibrinolytic System and the Risk of Ovarian Cancer

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    INTRODUCTION: The etiology of ovarian cancer is largely unknown. One hypothesis is that the inefficient removal of the blood clots and fibrin products which are deposited in the vicinity of the ovary by retrograde menstruation might be associated with an increased risk of ovarian cancer. Several single nucleotide polymorphisms within genes which comprise the fibrinolytic system have been shown to have functional effects on the rate of blood clot degradation. These were considered to be candidate genes in the present study. AIM: We studied the genotype distributions of 12 functional SNPs of four genes (tPA, uPA PAI1 and TAFI) among 775 ovarian cancer cases and 889 controls. RESULTS: No significant associations were seen between any of the ten SNPs and the risk of ovarian cancer as a whole, or in any histologic subgroup. DISCUSSION: Germline known functional variants of genes in the fibrinolytic system are not associated with risk of ovarian cancer

    Investigation of optical coherence micro-elastography as a method to visualize micro-architecture in human axillary lymph nodes

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    This project is supported with funding from the Australian Research Council; and Cancer Council WA, which allowed us to develop the technology; Department of Health of Western Australia, National Breast Cancer Foundation (Australia); and the National Health and Medical Research Council, Australia, which allowed us to design and implement the clinical protocol, and to perform the clinical measurements.Background : Evaluation of lymph node involvement is an important factor in detecting metastasis and deciding whether to perform axillary lymph node dissection (ALND) in breast cancer surgery. As ALND is associated with potentially severe long term morbidity, the accuracy of lymph node assessment is imperative in avoiding unnecessary ALND. The mechanical properties of malignant lymph nodes are often distinct from those of normal nodes. A method to image the micro-scale mechanical properties of lymph nodes could, thus, provide diagnostic information to aid in the assessment of lymph node involvement in metastatic cancer. In this study, we scan axillary lymph nodes, freshly excised from breast cancer patients, with optical coherence micro-elastography (OCME), a method of imaging micro-scale mechanical strain, to assess its potential for the intraoperative assessment of lymph node involvement. Methods : Twenty-six fresh, unstained lymph nodes were imaged from 15 patients undergoing mastectomy or breast-conserving surgery with axillary clearance. Lymph node specimens were bisected to allow imaging of the internal face of each node. Co-located OCME and optical coherence tomography (OCT) scans were taken of each sample, and the results compared to standard post-operative hematoxylin-and-eosin-stained histology. Results : The optical backscattering signal provided by OCT alone may not provide reliable differentiation by inspection between benign and malignant lymphoid tissue. Alternatively, OCME highlights local changes in tissue strain that correspond to malignancy and are distinct from strain patterns in benign lymphoid tissue. The mechanical contrast provided by OCME complements the optical contrast provided by OCT and aids in the differentiation of malignant tumor from uninvolved lymphoid tissue. Conclusion : The combination of OCME and OCT images represents a promising method for the identification of malignant lymphoid tissue. This method shows potential to provide intraoperative assessment of lymph node involvement, thus, preventing unnecessary removal of uninvolved tissues and improving patient outcomes.Publisher PDFPeer reviewe

    Novae Ejecta as Colliding Shells

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    Following on our initial absorption-line analysis of fifteen novae spectra we present additional evidence for the existence of two distinct components of novae ejecta having different origins. As argued in Paper I one component is the rapidly expanding gas ejected from the outer layers of the white dwarf by the outburst. The second component is pre-existing outer, more slowly expanding circumbinary gas that represents ejecta from the secondary star or accretion disk. We present measurements of the emission-line widths that show them to be significantly narrower than the broad P Cygni profiles that immediately precede them. The emission profiles of novae in the nebular phase are distinctly rectangular, i.e., strongly suggestive of emission from a relatively thin, roughly spherical shell. We thus interpret novae spectral evolution in terms of the collision between the two components of ejecta, which converts the early absorption spectrum to an emission-line spectrum within weeks of the outburst. The narrow emission widths require the outer circumbinary gas to be much more massive than the white dwarf ejecta, thereby slowing the latter's expansion upon collision. The presence of a large reservoir of circumbinary gas at the time of outburst is suggestive that novae outbursts may sometime be triggered by collapse of gas onto the white dwarf, as occurs for dwarf novae, rather than steady mass transfer through the inner Lagrangian point.Comment: 12 pages, 3 figures; Revised manuscript; Accepted for publication in Astrophysics & Space Scienc
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