1,142 research outputs found

    Dietary flavonoid intake and Barrett's esophagus in western Washington State

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    Flavonoids, concentrated in fruits and vegetables, demonstrate in experimental studies chemopreventive properties in relation to Barrett's esophagus (BE), a precursor lesion for esophageal adenocarcinoma. One case-control investigation reported an inverse association between isoflavone intake and odds of BE, yet no epidemiologic study has considered other flavonoid classes, which are more commonly consumed by Americans

    Honeybee Colony Vibrational Measurements to Highlight the Brood Cycle

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    Insect pollination is of great importance to crop production worldwide and honey bees are amongst its chief facilitators. Because of the decline of managed colonies, the use of sensor technology is growing in popularity and it is of interest to develop new methods which can more accurately and less invasively assess honey bee colony status. Our approach is to use accelerometers to measure vibrations in order to provide information on colony activity and development. The accelerometers provide amplitude and frequency information which is recorded every three minutes and analysed for night time only. Vibrational data were validated by comparison to visual inspection data, particularly the brood development. We show a strong correlation between vibrational amplitude data and the brood cycle in the vicinity of the sensor. We have further explored the minimum data that is required, when frequency information is also included, to accurately predict the current point in the brood cycle. Such a technique should enable beekeepers to reduce the frequency with which visual inspections are required, reducing the stress this places on the colony and saving the beekeeper time

    TbPIF5 Is a Trypanosoma brucei Mitochondrial DNA Helicase Involved in Processing of Minicircle Okazaki Fragments

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    Trypanosoma brucei's mitochondrial genome, kinetoplast DNA (kDNA), is a giant network of catenated DNA rings. The network consists of a few thousand 1 kb minicircles and several dozen 23 kb maxicircles. Here we report that TbPIF5, one of T. brucei's six mitochondrial proteins related to Saccharomyces cerevisiae mitochondrial DNA helicase ScPIF1, is involved in minicircle lagging strand synthesis. Like its yeast homolog, TbPIF5 is a 5′ to 3′ DNA helicase. Together with other enzymes thought to be involved in Okazaki fragment processing, TbPIF5 localizes in vivo to the antipodal sites flanking the kDNA. Minicircles in wild type cells replicate unidirectionally as theta-structures and are unusual in that Okazaki fragments are not joined until after the progeny minicircles have segregated. We now report that overexpression of TbPIF5 causes premature removal of RNA primers and joining of Okazaki fragments on theta structures. Further elongation of the lagging strand is blocked, but the leading strand is completed and the minicircle progeny, one with a truncated H strand (ranging from 0.1 to 1 kb), are segregated. The minicircles with a truncated H strand electrophorese on an agarose gel as a smear. This replication defect is associated with kinetoplast shrinkage and eventual slowing of cell growth. We propose that TbPIF5 unwinds RNA primers after lagging strand synthesis, thus facilitating processing of Okazaki fragments

    Geochemistry, faunal composition and trophic structure in reducing sediments on the southwest South Georgia margin

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    Despite a number of studies in areas of focused methane seepage, the extent of transitional sediments of more diffuse methane seepage, and their influence upon biological communities is poorly understood. We investigated an area of reducing sediments with elevated levels of methane on the South Georgia margin around 250 m depth and report data from a series of geochemical and biological analyses. Here, the geochemical signatures were consistent with weak methane seepage and the role of sub-surface methane consumption was clearly very important, preventing gas emissions into bottom waters. As a result, the contribution of methane-derived carbon to the microbial and metazoan food webs was very limited, although sulfur isotopic signatures indicated a wider range of dietary contributions than was apparent from carbon isotope ratios. Macrofaunal assemblages had high dominance and were indicative of reducing sediments, with many taxa common to other similar environments and no seep-endemic fauna, indicating transitional assemblages. Also similar to other cold seep areas, there were samples of authigenic carbonate, but rather than occurring as pavements or sedimentary concretions, these carbonates were restricted to patches on the shells of Axinulus antarcticus (Bivalvia, Thyasiridae), which is suggestive of microbe–metazoan interactions

    Neutrinoless double beta decay in seesaw models

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    We study the general phenomenology of neutrinoless double beta decay in seesaw models. In particular, we focus on the dependence of the neutrinoless double beta decay rate on the mass of the extra states introduced to account for the Majorana masses of light neutrinos. For this purpose, we compute the nuclear matrix elements as functions of the mass of the mediating fermions and estimate the associated uncertainties. We then discuss what can be inferred on the seesaw model parameters in the different mass regimes and clarify how the contribution of the light neutrinos should always be taken into account when deriving bounds on the extra parameters. Conversely, the extra states can also have a significant impact, cancelling the Standard Model neutrino contribution for masses lighter than the nuclear scale and leading to vanishing neutrinoless double beta decay amplitudes even if neutrinos are Majorana particles. We also discuss how seesaw models could reconcile large rates of neutrinoless double beta decay with more stringent cosmological bounds on neutrino masses.Comment: 34 pages, 5 eps figures and 1 axodraw figure. Final version published in JHEP. NME results available in Appendi

    Multi-Locus Sequence Analysis Reveals Profound Genetic Diversity among Isolates of the Human Pathogen Bartonella bacilliformis

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    Bartonella bacilliformis is the aetiological agent of human bartonellosis, a potentially life threatening infection of significant public health concern in the Andean region of South America. Human bartonellosis has long been recognised in the region but a recent upsurge in the number of cases of the disease and an apparent expansion of its geographical distribution have re-emphasized its contemporary medical importance. Here, we describe the development of a multi-locus sequence typing (MLST) scheme for B. bacilliformis and its application to an archive of 43 isolates collected from patients across Peru. MLST identified eight sequence types among these isolates and the delineation of these was generally congruent with those of the previously described typing scheme. Phylogenetic analysis based on concatenated sequence data derived from MLST loci revealed that seven of the eight sequence types were closely related to one another; however, one sequence type, ST8, exhibited profound evolutionary divergence from the others. The extent of this divergence was akin to that observed between other members of the Bartonella genus, suggesting that ST8 strains may be better considered as members of a novel Bartonella genospecies

    Cancer patients' needs during hospitalisation: a quantitative and qualitative study

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    BACKGROUND: The evaluation of cancer patients needs, especially during that delicate period when they are hospitalized, allows the identification of those areas of care that require to be improved. Aims of the study were to evaluate the needs in cancer inpatients and to improve the understanding of the meanings of the needs expressed. METHODS: The study was conducted during a "sample day", with all the cancer patients involved having been hospitalized at the Istituto Nazionale Tumori of Milan (INT) for at least 48 hours beforehand. The study was carried out using quantitative and qualitative methodologies. The quantitative part of the study consisted in making use of the Needs Evaluation Questionnaire (NEQ), a standardized questionnaire administered by the INT Psychology Unit members, supported by a group of volunteers from the Milan section of the Italian League Against Cancer. The aim of the qualitative part of the study, by semi-structured interviews conducted with a small sample of 8 hospitalized patients, was to improve our understanding of the meanings, implications of the needs directly described from the point of view of the patients. Such an approach determines the reasons and conditions of the dissatisfaction in the patient, and provides additional information for the planning of improvement interventions. RESULTS: Of the 224 eligible patients, 182 (81%) completed the questionnaire. Four of the top five needs expressed by 40% or more of the responders concerned information needs (diagnosis, future conditions, dialogue with doctors, economic-insurance solutions related to the disease). Only one of the 5 was concerned with improved "hotel" services (bathrooms, meals, cleanliness). Qualitative analysis showed that the most expressed need (to receive more information on their future conditions) has the meaning to know how their future life will be affected more than to know his/her actual prognosis. CONCLUSIONS: Some of the needs which emerged from this investigation could be immediately satisfied (the need for psychological support, the need for economic aid, the need for spiritual support), while others will have to be faced in the longer term; for example, the presence of a high percentage of needs in patient-physician relationships and/or information-communication issues, could be resolved by setting up structured introductory training courses for all clinicians in the institution. On the other hand, the needs related to the living infrastructure (bathrooms, meals, etc...) could encourage the Institution to improve its services

    Magnetism, FeS colloids, and Origins of Life

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    A number of features of living systems: reversible interactions and weak bonds underlying motor-dynamics; gel-sol transitions; cellular connected fractal organization; asymmetry in interactions and organization; quantum coherent phenomena; to name some, can have a natural accounting via physicalphysical interactions, which we therefore seek to incorporate by expanding the horizons of `chemistry-only' approaches to the origins of life. It is suggested that the magnetic 'face' of the minerals from the inorganic world, recognized to have played a pivotal role in initiating Life, may throw light on some of these issues. A magnetic environment in the form of rocks in the Hadean Ocean could have enabled the accretion and therefore an ordered confinement of super-paramagnetic colloids within a structured phase. A moderate H-field can help magnetic nano-particles to not only overcome thermal fluctuations but also harness them. Such controlled dynamics brings in the possibility of accessing quantum effects, which together with frustrations in magnetic ordering and hysteresis (a natural mechanism for a primitive memory) could throw light on the birth of biological information which, as Abel argues, requires a combination of order and complexity. This scenario gains strength from observations of scale-free framboidal forms of the greigite mineral, with a magnetic basis of assembly. And greigite's metabolic potential plays a key role in the mound scenario of Russell and coworkers-an expansion of which is suggested for including magnetism.Comment: 42 pages, 5 figures, to be published in A.R. Memorial volume, Ed Krishnaswami Alladi, Springer 201

    Measuring Anxiety in Youth with Learning Disabilities: Reliability and Validity of the Multidimensional Anxiety Scale for Children (MASC)

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    Youth with learning disabilities (LD) are at an increased risk for anxiety disorders and valid measures of anxiety are necessary for assessing this population. We investigated the psychometric properties of the Multidimensional Anxiety Scale for Children (MASC; March in Multidimensional anxiety scale for children. Multi-Health Systems, North Tonawanda, 1998) in 41 adolescents (ages 11– 17 years) with LD. Youth and parents completed the MASC and were administered the semi-structured Anxiety Disorders Interview Schedule: Child and Parent Versions (ADIS: C/P; Silverman and Albano in The Anxiety Disorders Interview Schedule for DSM-IV-Child and Parent Versions. Psychological Corporation, San Antonio, 1996). Results found that child and parent reports of Social Anxiety on the MASC closely corresponded with ADIS-generated social phobia diagnoses, and parent total scores discriminated well among youth with and without any anxiety disorder. A multi-method multi-trait matrix provided evidence of the construct validity of the MASC total score for both parent and child reports. Our findings provide empirical evidence that parent and child versions of the MASC are useful for assessing anxiety in youth with LD

    What You Find Depends on How You Measure It: Reactivity of Response Scales Measuring Predecisional Information Distortion in Medical Diagnosis

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    “Predecisional information distortion” occurs when decision makers evaluate new information in a way that is biased towards their leading option. The phenomenon is well established, as is the method typically used to measure it, termed “stepwise evolution of preference” (SEP). An inadequacy of this method has recently come to the fore: it measures distortion as the total advantage afforded a leading option over its competitor, and therefore it cannot differentiate between distortion to strengthen a leading option (“proleader” distortion) and distortion to weaken a trailing option (“antitrailer” distortion). To address this, recent research introduced new response scales to SEP. We explore whether and how these new response scales might influence the very proleader and antitrailer processes that they were designed to capture (“reactivity”). We used the SEP method with concurrent verbal reporting: fifty family physicians verbalized their thoughts as they evaluated patient symptoms and signs (“cues”) in relation to two competing diagnostic hypotheses. Twenty-five physicians evaluated each cue using the response scale traditional to SEP (a single response scale, returning a single measure of distortion); the other twenty-five did so using the response scales introduced in recent studies (two separate response scales, returning two separate measures of distortion: proleader and antitrailer). We measured proleader and antitrailer processes in verbalizations, and compared verbalizations in the single-scale and separate-scales groups. Response scales did not appear to affect proleader processes: the two groups of physicians were equally likely to bolster their leading diagnosis verbally. Response scales did, however, appear to affect antitrailer processes: the two groups denigrated their trailing diagnosis verbally to differing degrees. Our findings suggest that the response scales used to measure information distortion might influence its constituent processes, limiting their generalizability across and beyond experimental studies
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