294 research outputs found

    Additional Siphonaptera Records From Small Mammals in the Central Upper Peninsula of Michigan

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    Fleas were collected from mammals during the period 1990-1992 in two upper peninsula counties. Identified specimens were compared to existing distribution records for both parasite and host. Only those records which are newly documented for county, upper peninsula or Michigan are listed. We report one previously unknown flea species and five new host records for Michigan. One host record is new for the upper peninsula. In addition, seven new host/parasite combinations are recorded for two central upper peninsula counties

    Siphonaptera Records and Host Associations From the Central and Eastern Upper Peninsula of Michigan

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    Fleas were collected from birds and mammals over a five year period in four upper peninsula counties. Identified specimens were compared to published records of distribution for the parasite species and its host species, and only those records which are new county distributions for host or parasite are listed. Four new host records for Michigan, four new flea distribution records for the upper peninsula, and 26 new county records are listed

    Experimental and statistical investigation of self-consolidating concrete mixture constituents for prestressed bridge girder fabrication

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    Self-consolidating concrete (SCC) has the potential to increase precast production and quality, especially for production of prestressed concrete (PSC) bridge girders due to its superior workability compared with conventional concrete (CC). To obtain desired fresh and hardened properties for the production of SCC PSC girders, many factors related to material characteristics and mixture proportioning must be considered. An experimental comparison of fresh and hardened properties of SCC mixtures made with different material constituents was conducted in this study. The ultimate objective of this paper is not only to provide an experimental program enabling the investigation of the effect of material constituents on the performance of SCC mixtures but also to gain more knowledge for improved production of SCC PSC girders. The experimental program was established based on technical findings from a literature review and additional input from a survey of several state departments of transportation (DOTs). The mixture constituents used to investigate SCC performance consisted of the type of cement and size and type of coarse aggregate. Testing methods included slump flow, visual stability index (VSI), J-ring, column segregation, and compressive strength. The testing results showed that the type, shape, and size of coarse aggregate have a dominant effect in terms of fresh properties and compressive strength; specifically, mixtures with river gravel had larger spreads than mixtures with crushed limestone. Cement type had the expected effect with mixtures using Type III cement developing higher early strength than those using Type I/II cement. A statistical analysis was performed to determine significant mixture parameters in terms of fresh and hardened properties. It was found that the fine aggregate content was the most significant parameter affecting both fresh and hardened properties\u27 behavior

    Nuclear magnetic resonance measurements reveal the origin of the Debye process in monohydroxy alcohols

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    Monohydroxy alcohols show a structural relaxation and at longer time scales a Debye-type dielectric peak. From spin-lattice relaxation experiments using different nuclear probes an intermediate, slower-than-structural dynamics is identified for n-butanol. Based on these findings and on diffusion measurements, a model of self-restructuring, transient chains is proposed. The model is demonstrated to explain consistently the so far puzzling observations made for this class of hydrogen-bonded glass forming liquids.Comment: 4 pages, 4 figure

    The specialized tomograph rotary table design in the T-Flex CAD system

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    Статья "Проектирование поворотного стола специализированного томографа в T-Fleх CAD" посвящена актуальной проблеме обеспечения правильного расположения объектов контроля в томографических комплексах. Представлен вариант конструкции поворотного стола, спроектированный в среде T-Fleх CAD.The article "Designing of the Rotary Table of the Specialized Tomograph in the T-Flex CAD system" is devoted to the urgent problem of the object correct arrangement control in a tomographic complex. The rotary table embodiment is designed with the T-Flex CAD system

    Optical Spectroscopy of IRAS 02091+6333

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    We present a detailed spectroscopic investigation, spanning four winters, of the asymptotic giant branch (AGB) star IRAS 02091+6333. Zijlstra & Weinberger (2002) found a giant wall of dust around this star and modelled this unique phenomenon. However their work suffered from the quality of the optical investigations of the central object. Our spectroscopic investigation allowed us to define the spectral type and the interstellar foreground extinction more precisely. Accurate multi band photometry was carried out. This provides us with the possibility to derive the physical parameters of the system. The measurements presented here suggest a weak irregular photometric variability of the target, while there is no evidence of a spectroscopic variability over the last four years.Comment: 5 pages, Latex, 3 tables, 4 figures, Astron. & Astrophys. - in pres

    Elective Open Suprarenal Aneurysm Repair in England from 2000 to 2010 an Observational Study of Hospital Episode Statistics

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    Background: Open surgery is widely used as a benchmark for the results of fenestrated endovascular repair of complex abdominal aortic aneurysms (AAA). However, the existing evidence stems from single-centre experiences, and may not be reproducible in wider practice. National outcomes provide valuable information regarding the safety of suprarenal aneurysm repair. Methods: Demographic and clinical data were extracted from English Hospital Episodes Statistics for patients undergoing elective suprarenal aneurysm repair from 1 April 2000 to 31 March 2010. Thirty-day mortality and five-year survival were analysed by logistic regression and Cox proportional hazards modeling. Results: 793 patients underwent surgery with 14% overall 30-day mortality, which did not improve over the study period. Independent predictors of 30-day mortality included age, renal disease and previous myocardial infarction. 5-year survival was independently reduced by age, renal disease, liver disease, chronic pulmonary disease, and known metastatic solid tumour. There was significant regional variation in both 30-day mortality and 5-year survival after risk-adjustment. Regional differences in outcome were eliminated in a sensitivity analysis for perioperative outcome, conducted by restricting analysis to survivors of the first 30 days after surgery. Conclusions: Elective suprarenal aneurysm repair was associated with considerable mortality and significant regional variation across England. These data provide a benchmark to assess the efficacy of complex endovascular repair of supra-renal aneurysms, though cautious interpretation is required due to the lack of information regarding aneurysm morphology. More detailed study is required, ideally through the mandatory submission of data to a national registry of suprarenal aneurysm repair

    Oral vitamin B(12 )therapy in the primary care setting: a qualitative and quantitative study of patient perspectives

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    BACKGROUND: Although oral replacement with high doses of vitamin B(12 )is both effective and safe for the treatment of B(12 )deficiency, little is known about patients' views concerning the acceptability and effectiveness of oral B(12). We investigated patient perspectives on switching from injection to oral B(12 )therapy. METHODS: This study involved a quantitative arm using questionnaires and a qualitative arm using semi-structured interviews, both to assess patient views on injection and oral therapy. Patients were also offered a six-month trial of oral B(12 )therapy. One hundred and thirty-three patients who receive regular B(12 )injections were included from three family practice units (two hospital-based academic clinics and one community health centre clinic) in Toronto. RESULTS: Seventy-three percent (63/86) of respondents were willing to try oral B(12). In a multivariate analysis, patient factors associated with a "willingness to switch" to oral B(12 )included being able to get to the clinic in less than 30 minutes (OR 9.3, 95% CI 2.2–40.0), and believing that frequent visits to the health care provider (OR 5.4, 95% CI 1.1–26.6) or the increased costs to the health care system (OR 16.7, 95% CI 1.5–184.2) were disadvantages of injection B(12). Fifty-five patients attempted oral therapy and 52 patients returned the final questionnaire. Of those who tried oral therapy, 76% (39/51) were satisfied and 71% (39/55) wished to permanently switch. Factors associated with permanently switching to oral therapy included believing that the frequent visits to the health care provider (OR 35.4, 95% CI 2.9–432.7) and travel/parking costs (OR 8.7, 95% CI 1.2–65.3) were disadvantages of injection B(12). Interview participants consistently cited convenience as an advantage of oral therapy. CONCLUSION: Switching patients from injection to oral B(12 )is both feasible and acceptable to patients. Oral B(12 )supplementation is well received largely due to increased convenience. Clinicians should offer oral B(12 )therapy to their patients who are currently receiving injections, and newly diagnosed B(12)-deficient patients who can tolerate and are compliant with oral medications should be offered oral supplementation

    Relationship of age, gender, race, and body size to infrarenal aortic diameter

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    AbstractPurpose: To assess the effects of age, gender, race, and body size on infrarenal aortic diameter (IAD) and to determine expected values for IAD on the basis of these factors.Methods: Veterans aged 50 to 79 years at 15 Department of Veterans Affairs medical centers were invited to undergo ultrasound measurement of IAD and complete a prescreening questionnaire. We report here on 69,905 subjects who had no previous history of abdominal aortic aneurysm (AAA) and no ultrasound evidence of AAA (defined as IAD ≥ 3.0 cm).Results: Although age, gender, black race, height, weight, body mass index, and body surface area were associated with IAD by multivariate linear regression (all p < 0.001), the effects were small. Female sex was associated with a 0.14 cm reduction in IAD and black race with a 0.01 cm increase in IAD. A 0.1 cm change in IAD was associated with large changes in the independent variables: 29 years in age, 19 cm or 40 cm in height, 35 kg in weight, 11 kg/m2 in body mass index, and 0.35 m2 in body surface area. Nearly all height-weight groups were within 0.1 cm of the gender means, and the unadjusted gender means differed by only 0.23 cm. The variation among medical centers had more influence on IAD than did the combination of age, gender, race, and body size.Conclusions: Age, gender, race, and body size have statistically significant but small effects on IAD. Use of these parameters to define AAA may not offer sufficient advantage over simpler definitions (such as an IAD ≥3.0 cm) to be warranted. (J Vasc Surg 1997;26:595-601.

    Should Research Ethics Encourage the Production of Cost-Effective Interventions?

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    This project considers whether and how research ethics can contribute to the provision of cost-effective medical interventions. Clinical research ethics represents an underexplored context for the promotion of cost-effectiveness. In particular, although scholars have recently argued that research on less-expensive, less-effective interventions can be ethical, there has been little or no discussion of whether ethical considerations justify curtailing research on more expensive, more effective interventions. Yet considering cost-effectiveness at the research stage can help ensure that scarce resources such as tissue samples or limited subject popula- tions are employed where they do the most good; can support parallel efforts by providers and insurers to promote cost-effectiveness; and can ensure that research has social value and benefits subjects. I discuss and rebut potential objections to the consideration of cost-effectiveness in research, including the difficulty of predicting effectiveness and cost at the research stage, concerns about limitations in cost-effectiveness analysis, and worries about overly limiting researchers’ freedom. I then consider the advantages and disadvantages of having certain participants in the research enterprise, including IRBs, advisory committees, sponsors, investigators, and subjects, consider cost-effectiveness. The project concludes by qualifiedly endorsing the consideration of cost-effectiveness at the research stage. While incorporating cost-effectiveness considerations into the ethical evaluation of human subjects research will not on its own ensure that the health care system realizes cost-effectiveness goals, doing so nonetheless represents an important part of a broader effort to control rising medical costs
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