1,671 research outputs found

    Integrated Anisian–Ladinian boundary chronology

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    We report magnetostratigraphic and biostratigraphic data from the Seceda core and the correlative outcrop section from the Dolomites of northern Italy. The Seceda rock succession consists of Tethyan marine limestones and radiometrically dated volcaniclastic layers of the Buchenstein Beds of Middle Triassic age (∼238–242 Ma). The Seceda outcrop section was correlated to coeval sections from the literature using magnetic polarity reversals and a selection of laterally traceable and isochronous lithostratigraphic marker beds. This allowed us to import the distribution of age-diagnostic conodonts, ammonoids, and daonellas from these sections into a Seceda reference stratigraphy for the construction of an integrated biochronology extending across a consistent portion of the Anisian–Ladinian boundary interval. Among the three options selected by the Subcommission for Triassic Stratigraphy to establish the Ladinian Global Stratigraphic Section and Point, we propose to adopt the level containing the base of the Curionii ammonoid Zone at Bagolino (Southern Alps, Italy) because this level is closely associated with a global means of correlation represented by the base of polarity submagnetozone SC2r.2r. The first occurrence of Neogondolella praehungarica in the Dolomites predates slightly the base of the Curionii Zone and can be used to approximate the Anisian–Ladinian boundary in the absence of ammonoids

    Three-dimensional harmonic oscillator and time evolution in quantum mechanics

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    The problem of defining time (or phase) operator for three-dimensional harmonic oscillator has been analyzed. A new formula for this operator has been derived. The results have been used to demonstrate a possibility of representing quantum-mechanical time evolution in the framework of an extended Hilbert space structure. Physical interpretation of the extended structure has been discussed shortly, too.Comment: 14 pages; submitted to Phys Rev

    Lithium and bipolar depression

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    Kelly1 has recently disputed the recommendations of several international guidelines on the use of lithium in bipolar depression. In his scrutiny, the author points to three main errors that seem to have affected systematically ten international guidelines, namely the Woozle effect (evidence by citation), reference inflation (inappropriate citation of pivotal, generally old, studies) and belief perseverance (inability to modify evidence‐based recommendations despite the presence of contrary data). We concur with the author that the evidence supporting the effectiveness of lithium in acute bipolar depression, and to a lesser degree also in major depressive episodes, remains inadequate.2, 3 A different matter is, in our opinion, to label guidelines recommendations as inaccurate or biased, even if, as the author stated, no deceptive intentions were present

    Towards a better definition of the Middle Triassic magnetostratigraphy and biostratigraphy in the Tethyan realm

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    Magnetostratigraphic and biostratigraphic data for the Middle Triassic (Anisian) were obtained from the Han-Bulog facies in the Nderlysaj section from the Albanian Alps and the Dont and Bivera formations in the Dont–Monte Rite composite section from the Dolomites region of northern Italy. The Nderlysaj section is biochronologically bracketed between the late Bithynian and early Illyrian substages (i.e., late-early and early-late Anisian), whereas the Dont–Monte Rite section comprises the late Pelsonian and the early Illyrian substages. The data from Nderlysaj and Dont–Monte Rite, in conjunction with already published data, allow us to construct a nearly complete composite geomagnetic polarity sequence tied to Tethyan ammonoid and conodont biostratigraphy from the late Olenekian (late-Early Triassic) to the late Ladinian (late-Middle Triassic). New conodont data require revision of the published age of the Vlichos section (Greece)

    Magnetostratigraphy and biostratigraphy of the Carnian/Norian boundary interval from the Pizzo Mondello section (Sicani Mountains, Sicily)

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    The 146.5 m-thick Upper Triassic limestone section at Pizzo Mondello in the Sicani Mountains of western Sicily is characterized by high quality of exposure, accessibility, and stratigraphic continuity. Magnetostratigraphic results delineate 12 normal and reverse polarity magnetozones, labelled successively from the base upwards as PM1n, PM1r, PM6n, PM6r. The Carnian/Norian boundary, based on conodont biostratigraphy, falls somewhere in the PM3n to PM5n interval which corresponds to the E14n to E16n magnetozone interval in the Newark reference sequence of polarity reversals. Comparison of magnetobiostratigraphic data from the Newark basin, Pizzo Mondello and other Late Triassic marine sections available from the literature suggests the existence of a reduction in sedimentation rate in the Tethyan marine domain at around the Carnian/Norian boundary. Although the Newark and the expanded Pizzo Mondello sections correlate well with each other, correlation with the condensed Kavur Tepe and Scheiblkogel sections is unsatisfactory. A re-interpretation of the Kavur Tepe results suggests that the section is younger than its previous correlation with the Newark section, and that it was deposited in the northern instead of the southern hemisphere. Most of the condensed Tethyan marine sections are seen to be highly discontinuous, as evidenced by concantenated conodont total range zones

    Foodborne infections in Iceland. Relationship to allergy and lung function

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    Neðst á síðunni er hægt að nálgast greinina í heild sinni með því að smella á hlekkinn View/OpenBACKGROUND: Foodborne or orofecal transmitted infections can have influence on health by direct consequences of the infection and indirectly by modulating the immune system. OBJECTIVES: To investigate the prevalence and risk factors for T. gondii, H. pylori and HAV infection in the Icelandic population and their influence on atopy, allergy related lung symptoms and lung function. MATERIAL AND METHODS: Blood samples were collected in 1999-2001 from 505 subjects in age group 28-52, randomly selected from the Icelandic population. The presence of T. gondii, H. pylori and HAV IgG antibodies was determined by an ELISA method. Allergy related lung symptoms were assessed with questionnaire and IgE sensitization and lung function measured. X(2) test was used to test for trend but unadjusted logistic regression for comparison of IgG prevalence. Multiple logistic regression was used to calculate adjusted odds ratios and 95% confidence intervals for different infections factors. RESULTS: The prevalence of antibodies was 9.8%, for T. gondii, 36.3% for H. pylori and 4.9% for HAV. Attending day care before the age of 3 years was a risk factor for having T. gondii antibodies. The prevalence of H. pylori increased with age and smoking. The infections were not associated with the prevalence of asthma or atopy. Having IgG antibodies against T. gondii was, however, associated with an increased risk of having FEV/FVC ratio below 70%. CONCLUSION: T. gondii, H. pylori and H AV infection does not influence the prevalence of atopy or asthma. The data indicated that infection with T. gondii might be associated with a diminished lung function

    Categorical differentiation of the unipolar and bipolar disorders

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    There has been a longstanding debate as to whether the bipolar disorders differ categorically or dimensionally, with some dimensional or spectrum models including unipolar depressive disorders within a bipolar spectrum model. We analysed manic/hypomanic symptom data in samples of clinically diagnosed bipolar I, bipolar II and unipolar patients, employing latent class analyses to determine if separate classes could be identified. Mixture analyses were also undertaken to determine if a unimodal, bimodal or a trimodal pattern was present. For both a refined 15-item set and an extended 30-item set of manic/hypomanic symptoms, our latent class analyses favoured three-class solutions, while mixture analyses identified trimodal distributions of scores. Findings argue for a categorical distinction between unipolar and bipolar disorders, as well as between bipolar I and bipolar II disorders. Future research should aim to consolidate these results in larger samples, particularly given that the size of the unipolar group in this study was a salient limitation

    The bipolar disorders: A case for their categorically distinct status based on symptom profiles

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    Background: It is unclear whether the bipolar disorders (i.e. BP-I/BP-II) differ dimensionally or categorically. This study sought to clarify this issue. Methods: We recruited 165 patients, of which 69 and 96 had clinician-assigned diagnoses of BP-I and BP-II respectively. Their psychiatrists completed a data sheet seeking information on clinical variables about each patient, while the patients completed a different data sheet and scored a questionnaire assessing the prevalence and severity of 96 candidate manic/hypomanic symptoms. Results: We conducted a series of analyses examining a set (and two sub-sets) of fifteen symptoms that were significantly more likely to be reported by the clinically diagnosed BP-I patients. Latent class analyses favoured two-class solutions, while mixture analyses demonstrated bimodality, thus arguing for a BP-I/BP-II categorical distinction. Statistically defined BP-I class members were more likely when manic to have experienced psychotic features and over-valued ideas. They were also more likely to have been hospitalised, and to have been younger when they received their bipolar diagnosis and first experienced a depressive or manic episode. Limitations: The lack of agreement between some patients and managing clinicians in judging the presence of psychotic features could have compromised some analyses. It is also unclear whether some symptoms (e.g. grandiosity, noting mystical events) were capturing formal psychotic features or not. Conclusions: Findings replicate our earlier study in providing evidence to support the modelling of BP-I and BP-II as categorically discrete conditions. This should advance research into aetiological factors and determining optimal (presumably differing) treatments for the two conditions
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