2,372 research outputs found

    Some features of the deep water in the Gulf of Mexico

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    In the central Gulf of Mexico, 52 stations having depths greater than 1500 m were occupied within a seven-week period. The data for waters below sill depth (2000 m) show that the ranges of potential temperature and salinity are very limited, although weak vertical gradients indicate a slight positive stability...

    A characterization of the Gulf of Mexico waters in winter

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    The results of a rapid survey of the Gulf of Mexico in the winter of 1962 are presented. Variations in the characteristics of the water in several core layers are described. Circulation has been examined on the basis of dynamic computations and G.E.K. measurements. In the eastern Gulf, water enters through Yucatan Strait and leaves through Florida Strait, flowing in an anticyclonic loop that extends well into the Gulf...

    Remarks on Legendrian Self-Linking

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    The Thurston-Bennequin invariant provides one notion of self-linking for any homologically-trivial Legendrian curve in a contact three-manifold. Here we discuss related analytic notions of self-linking for Legendrian knots in Euclidean space. Our definition is based upon a reformulation of the elementary Gauss linking integral and is motivated by ideas from supersymmetric gauge theory. We recover the Thurston-Bennequin invariant as a special case.Comment: 42 pages, many figures; v2: minor revisions, published versio

    Induction of Colonic Aberrant Crypts in Mice by Feeding Apparent N-Nitroso Compounds Derived From Hot Dogs

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    Nitrite-preserved meats (e.g., hot dogs) may help cause colon cancer because they contain N-nitroso compounds. We tested whether purified hot-dog-derived total apparent N-nitroso compounds (ANC) could induce colonic aberrant crypts, which are putative precursors of colon cancer. We purified ANC precursors in hot dogs and nitrosated them to produce ANC. In preliminary tests, CF1 mice received 1 or 3 i.p. injections of 5mg azoxymethane (AOM)/kg. In Experiments 1 and 2, female A/J mice received ANC in diet. In Experiment 1, ANC dose initially dropped sharply because the ANC precursors had mostly decomposed but, later in Experiment 1 and throughout Experiment 2, ANC remained at 85 nmol/g diet. Mice were killed after 8 (AOM tests) or 17–34 (ANC tests) wk.Median numbers of aberrant crypts in the distal 2 cm of the colon for 1 and 3 AOMinjections, CF1 controls, ANC (Experiment 1), ANC (Experiment 2),and untreated A/J mice were 31, 74, 12, 20, 12, and 5–6, with P < 0.01 for both ANC tests. Experiment 2 showed somewhat increased numbers of colonic mucin-depleted foci in the ANC-treated group. We conclude that hot-dog-derived ANC induced significant numbers of aberrant crypts in the mouse colon

    Little groups of irreps of O(3), SO(3), and the infinite axial subgroups

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    Little groups are enumerated for the irreps and their components in any basis of O(3) and SO(3) up to rank 9, and for all irreps of C∞_{\infty}, C∞h_{\infty h}, C∞v_{\infty v}, D∞_{\infty} and D∞h_{\infty h}. The results are obtained by a new chain criterion, which distinguishes massive (rotationally inequivalent) irrep basis functions and allows for multiple branching paths, and are verified by inspection. These results are relevant to the determination of the symmetry of a material from its linear and nonlinear optical properties and to the choices of order parameters for symmetry breaking in liquid crystals.Comment: 28 pages and 3 figure

    Performance of point-of-care HbA1c test devices: implications for use in clinical practice – a systematic review and meta-analysis

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    Regular monitoring of glycated hemoglobin subfraction A1c (HbA1c) in people with diabetes and treatment with glucose-lowering medications to improve glycaemic control can reduce the risk of developing complications [1]. In 2011, a World Health Organization consultation concluded that HbA1cat a threshold of 6.5% (48 mmol/mol) can be used as a diagnostic test for diabetes [2]. HbA1c monitoring often requires the patient to attend the health center twice: once to have blood taken and then returning to get test results and receive adjustments to medication. Point-of-care (POC) analysers are bench-top instruments that use a finger-prick blood sample and are designed for use in a treatment room or at the bed-side. They provide a test result within a few minutes allowing clinical decisions and medication changes to take place immediately. The suitability of many of these devices for the accurate measurement of HbA1c has been questioned, with some POC HbA1c test devices reported not to meet accepted accuracy and precision criteria [3]. Ideal imprecision goals for HbA1c should be coefficient of variation (CV) of <2% for HbA1c reported in % units (or <3% in SI units, mmol/mol) [4], [5], [6]. Most evaluations of POC HbA1c devices have taken place in laboratory settings [7], [8]; fewer studies have assessed device performance in a POC setting or with clinicians performing the tests [9], [10]. The only published review that has attempted to combine data from accuracy studies identified five studies covering three devices and compared correlation coefficients [11]. Systematically reporting and pooling data estimates of bias and precision between POC HbA1c devices and laboratory measurements would enable end users to assess which analysers best meet their analytical performance needs. This may be of particular importance for clinicians in primary care settings where much of the management of diabetes patients takes place. The comparison of accuracy between devices over the entire therapeutic range would need to be carried out by combining data on measurement error (bias) between POC and laboratory tests [12]. The aim of this study was to compare accuracy and precision of POC HbA1c devices with the local laboratory method based on data from published studies and discuss the clinical implications of the findings

    A Study to Validate a Self-Reported Version of the ONS Drug Dependence Questionnaire

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    Aim: A prospective study to establish the reliability of a self-completion version of the Office for National Statistics (ONS) questionnaire for assessing drug dependence of substance misuse clients. Method: A total of 47 treatment seeking opioid-dependent clients completed the self-complete version of the ONS questionnaire (ONS-sc) followed by the interviewer-administered ONS questionnaire (ONS-ia) at a single clinic appointment. Scores for four Class A drugs (heroin, methadone, speed and crack/cocaine) from both formats were compared. Results: The observed agreement was 87% or more and Cohen's kappa was 0.7 (p < 0.001) or more for all four Class A drugs. Sensitivity for each Class A drugs was 56% or higher and specificity was 87% or higher. Sensitivity for severe heroin dependency was 98% (CI 89–100%). There was a 100% correlation between the ONS-sc and positive urine analysis for heroin use. However, methadone and crack/cocaine drug use appeared under reported. Conclusion: ONS-sc is a feasible, practical and time-saving alternative to a detailed interview on drug dependence. Further research with a larger sample size and non-opiate-dependent clients are needed, as this could prove a useful tool for monitoring clients in everyday practice, or for survey purposes where interviews are impractical
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