460 research outputs found

    Radiocarbon and stable isotope evidence of dietary change from the Mesolithic to the Middle Ages in the iron gates: New results from Lepenski Vir

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    A previous radiocarbon dating and stable isotope study of directly associated ungulate and human bone samples from Late Mesolithic burials at Schela Cladovei in Romania established that there is a freshwater reservoir effect of approximately 500 yr in the Iron Gates reach of the Danube River valley in southeast Europe. Using the delta(15)N values as an indicator of the percentage of freshwater protein in the human diet, the C-14 data for 24 skeletons from the site of Lepenski Vir were corrected for this reservoir effect. The results of the paired C-14 and stable isotope measurements provide evidence of substantial dietary change over the period from about 9000 BP to about 300 BR The data from the Early Mesolithic to the Chalcolithic are consistent with a 2-component dietary system, where the linear plot of isotopic values reflects mixing between the 2 end-members to differing degrees. Typically, the individuals of Mesolithic age have much heavier delta(15)N signals and slightly heavier delta(13)C, while individuals of Early Neolithic and Chalcolithic age have lighter delta(15)N and delta(13)C values. Contrary to our earlier suggestion, there is no evidence of a substantial population that had a transitional diet midway between those that were characteristic of the Mesolithic and Neolithic. However, several individuals with "Final Mesolithic" C-14 ages show delta(15)N and delta(13)C values that are similar to the Neolithic dietary pattern. Provisionally, these are interpreted either as incomers who originated in early farming communities outside the Iron Gates region or as indigenous individuals representing the earliest Neolithic of the Iron Gates. The results from Roman and Medieval age burials show a deviation from the linear function, suggesting the presence of a new major dietary component containing isotopically heavier carbon. This is interpreted as a consequence of the introduction of millet into the human food chain

    Loop Corrections in the Spectrum of 2D Hawking Radiation

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    We determine the one-loop and the two-loop back-reaction corrections in the spectrum of the Hawking radiation for the CGHS model of 2d dilaton gravity by evaluating the Bogoliubov coefficients for a massless scalar field propagating on the corresponding backgrounds. Since the back-reaction can induce a small shift in the position of the classical horizon, we find that a positive shift leads to a non-Planckian late-time spectrum, while a null or a negative shift leads to a Planckian late-time spectrum in the leading-order stationary-point approximation. In the one-loop case there are no corrections to the classical Hawking temperature, while in the two-loop case the temperature is three times greater than the classical value. We argue that these results are consistent with the behaviour of the Hawking flux obtained from the operator quantization only for the times which are not too late, in accordance with the limits of validity of the semiclassical approximation.Comment: 20 pages, latex, no figure

    One-Loop Effective Action for Spherical Scalar Field Collapse

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    We calculate the complete one-loop effective action for a spherical scalar field collapse in the large radius approximation. This action gives the complete trace anomaly, which beside the matter loop contributions, receives a contribution from the graviton loops. Our result opens a possibility for a systematic study of the back-reaction effects for a real black hole.Comment: 14 pages, slightly expanded version to appear in Class. Quant. Gra

    2D Hybrid method:Case of VLF signal amplitude variations in the time vicinity of an earthquake

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    Extraction of information in the form of oscillations from noisy data of natural phenomena such as sounds, earthquakes, ionospheric and brain activity, and various emissions from cosmic objects is extremely difficult. As a method for finding periodicity in such challenging data sets, the 2D Hybrid approach, which employs wavelets, is presented. Our technique produces a wavelet transform correlation intensity contour map for two (or one) time series on a period plane defined by two independent period axes. Notably, by spreading peaks across the second dimension, our method improves apparent resolution of detected oscillations in the period plane and identifies the direction of signal changes using correlation coefficients. We demonstrate the performance of the 2D Hybrid technique on a very low frequency (VLF) signal emitted in Italy and recorded in Serbia in time vicinity of the occurrence of an earthquake on November 3, 2010, near Kraljevo, Serbia. We identified a distinct signal in the range 120-130 s that appears only in association with the considered earthquake. Other wavelets, such as Superlets, which may detect fast transient oscillations, will be employed in the future analysis.Comment: published in Mathematics MDP

    Is pretreatment with Beta-blockers beneficial in patients with acute coronary syndrome?

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    OBJECTIVES: The role of beta-blockers in the treatment of hypertension is discussed controversially and the data showing a clear benefit in acute coronary syndromes (ACS) were obtained in the thrombolysis era. The goal of this study was to analyze the role of pretreatment with beta-blockers in patients with ACS. METHODS: Using data from the Acute Myocardial Infarction in Switzerland (AMIS Plus) registry, we analyzed outcomes of patients with beta-blocker pretreatment in whom they were continued during hospitalization (group A), those without beta-blocker pretreatment but with administration after admission (group B) and those who never received them (group C). Major adverse cardiac events defined as composed endpoint of re-infarction and stroke (during hospitalization) and/or in-hospital death were compared between the groups. RESULTS: A total of 24,709 patients were included in the study (6,234 in group A, 12,344 in group B, 6,131 in group C). Patients of group B were younger compared to patients of group A and C (62.5, 67.6 and 68.4, respectively). In the multivariate analysis, odds ratio for major adverse cardiac events was 0.59 (CI 0.47-0.74) for group A and 0.66 (CI 0.55-0.83) for group B, while group C was taken as a reference. CONCLUSIONS: beta-Blocker therapy is beneficial in ACS and they should be started in those who are not pretreated and continued in stable patients who had been on chronic beta-blocker therapy before

    RADIOCARBON AND STABLE ISOTOPE EVIDENCE OF DIETARY CHANGE FROM THE MESOLITHIC TO THE MIDDLE AGES IN THE IRON GATES: NEW RESULTS FROM LEPENSKI VIR

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    This is the published version, also available here: https://journals.uair.arizona.edu/index.php/radiocarbon/article/view/4269.A previous radiocarbon dating and stable isotope study of directly associated ungulate and human bone samples from Late Mesolithic burials at Schela Cladovei in Romania established that there is a freshwater reservoir effect of approximately 500 yr in the Iron Gates reach of the Danube River valley in southeast Europe. Using the d15N values as an indicator of the percentage of freshwater protein in the human diet, the 14C data for 24 skeletons from the site of Lepenski Vir were corrected for this reservoir effect. The results of the paired 14C and stable isotope measurements provide evidence of substantial dietary change over the period from about 9000 BP to about 300 BP. The data from the Early Mesolithic to the Chalcolithic are consistent with a 2-component dietary system, where the linear plot of isotopic values reflects mixing between the 2 end-members to differing degrees. Typically, the individuals of Mesolithic age have much heavier d15N signals and slightly heavier d13C, while individuals of Early Neolithic and Chalcolithic age have lighter d15N and d13C values. Contrary to our earlier suggestion, there is no evidence of a substantial population that had a transitional diet midway between those that were characteristic of the Mesolithic and Neolithic. However, several individuals with Final Mesolithic 14C ages show d15N and d13C values that are similar to the Neolithic dietary pattern. Provisionally, these are interpreted either as incomers who originated in early farming communities outside the Iron Gates region or as indigenous individuals representing the earliest Neolithic of the Iron Gates. The results from Roman and Medieval age burials show a deviation from the linear function, suggesting the presence of a new major dietary component containing isotopically heavier carbon. This is interpreted as a consequence of the introduction of millet into the human food chain

    Effects of anti-IL5 biological treatments on blood IgE levels in severe asthmatic patients: A real-life multicentre study (BIONIGE)

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    Background: Mepolizumab and benralizumab are clinically effective biological treatments for severe eosinophilic asthmatic patients by hampering eosinophilic inflammation. The effects of these compound on the immunoglobulin (Ig)E T2 component are virtually unknown. Objectives: To evaluate the change in total IgE levels at 4 Â± 2 months after initiation of the mepolizumab (primary outcome) or benralizumab. When available, the changes of blood inflammatory cell counts, lung function and asthma control test (ACT) were also assessed and correlated with changes in total IgE levels. Methods: Observational, retrospective, multicentre, cohort study. Severe eosinophilic atopic asthmatic patients treated with mepolizumab or benralizumab were included in the analysis. Results: Three-month treatment (on average) with mepolizumab (n = 104) or benralizumab (n = 82) resulted in significantly higher reduction of blood eosinophil and basophil levels in patients treated with benralizumab compared to mepolizumab. Mepolizumab did not significantly modified the levels of blood total IgE during the study period, whereas benralizumab significantly reduced (−35%, p < 0.001) total blood IgE levels. In patients treated with benralizumab the reduction of blood total Ig-E levels correlated with the reduction of blood basophils (but not eosinophils) and weakly with the improvement of asthma control. Conclusion: Benralizumab but not mepolizumab, treatment led to a significant reduction of circulating IgE level. The study provides different and specific mechanisms of action for anti-IL5-pathway treatments

    A comprehensive approach to lung function in bronchiectasis

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    Background: International guidelines recommend simple spirometry for bronchiectasis patients. However, pulmonary pathophysiology of bronchiectasis is very complex and still poorly understood. Our objective was to characterize lung function in bronchiectasis and identify specific functional sub-groups. Methods: This was a multicenter, prospective, observational study enrolling consecutive adults with bronchiectasis during stable sate. Patients underwent body-plethysmography before and after acute bronchodilation testing, diffusing lung capacity (DLCO) with a 3-year follow up. Air trapping and hyperinflation were a residual volume (RV) > 120%predicted and a total lung capacity>120%predicted. Acute reversibility was: \u394FEV1 6512% and 200 mL from baseline (FEV1rev) and \u394RV 6510% reduction from baseline (RVrev). Sensitivity analyses included different reversibility cutoffs and excluded patients with concomitant asthma or chronic obstructive pulmonary disease. Results: 187 patients were enrolled (median age: 68 years; 29.4% males). Pathophysiological abnormalities often overlapped and were distributed as follows: air trapping (70.2%), impaired DLCO (55.7%), airflow obstruction (41.1%), hyperinflation (15.7%) and restriction (8.0%). 9.7% of patients had normal lung function. RVrev (17.6%) was more frequent than FEV1rev (4.3%). Similar proportions were found after multiple sensitivity analyses. Compared with non-reversible patients, patients with RVrev had more severe obstruction (mean(SD) FEV1%pred: 83.0% (24.4) vs 68.9% (26.2); P = 0.02) and air trapping (RV%pred, 151.9% (26.6) vs 166.2% (39.9); P = 0.028). Conclusions: Spirometry alone does not encompass the variety of pathophysiological characteristics in bronchiectasis. Air trapping and diffusion impairment, not airflow obstruction, represent the most common functional abnormalities. RVrev is related to worse lung function and might be considered in bronchiectasis\u2019 workup and for patients\u2019 functional stratification
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