28 research outputs found

    Forward jet production in deep inelastic ep scattering and low-x parton dynamics at HERA

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    Differential inclusive jet cross sections in neutral current deep inelastic ep scattering have been measured with the ZEUS detector. Three phase-space regions have been selected in order to study parton dynamics where the effects of BFKL evolution might be present. The measurements have been compared to the predictions of leading-logarithm parton shower Monte Carlo models and fixed-order perturbative QCD calculations. In the forward region, QCD calculations at order alpha_s^1 underestimate the data up to an order of magnitude at low x. An improved description of the data in this region is obtained by including QCD corrections at order alpha_s^2, which account for the lowest-order t-channel gluon-exchange diagrams, highlighting the importance of such terms in parton dynamics at low x.Comment: 25 pages, 4 figure

    Exploratory data analysis

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    Definition of reference values for Cd-B and Cd-U: methodological aspects and preliminary results

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    In the present study, a definition of the reference values of blood cadmium (Cd-B) and urinary cadmium (Cd-U) was attempted, adopting the same methodology as that used for Hg-B by ICOH and IUPAC. Papers published from 1976 onwards were reviewed. The majority of the studies were concerned with the formation of control groups for toxicological and epidemiological investigations rather than with the definition of reference values. Since the number of subjects for whom data on cadmium were available was small, only the data on Cd-B were considered. After evaluation, only four studies were found to be suitable for the establishment of tentative reference values for Cd-B. It is essential in all such studies to check the statistical and analytical methods for correctness, and the case-list must be selected taking smoking into account as the main interfering factor. It was found that Cd-B values show less dispersion when geometric means and standard geometric deviations are used instead of arithmetic means and standard deviations

    Perdita uditiva dei lavoratori del comparto ceramica: profilo di danno valutato mediante studio longitudinale

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    Over the period 1980-1990, 2024 workers in ceramic plants in the Emilia-Romagna region, Italy were evaluated for exposure to noise and hearing loss. Data collected by the National Health Service Local of Occupational and Preventive Medicine Units were used. In a relatively young population (34.8 years mean age, 8.98 years s.d.) exposed for not too long to > 90 dBA noise levels (87.2 for less than 4 years) a statistically significant effect of exposure was found only on the audiometric frequency of 6 kHz (95% confidence interval for mean hearing loss for 1 year exposure to > 90 dBA: 0.05-0.72 dB). An initial isolated loss at the audiometric frequency of 6 kHz was found to be significantly associated with (was a prognostic indicator of) a subsequent impairment at 4 kHz

    Selection for necropsy: evaluation of 321 autopsied cases from 3041 consecutive deaths among residents of a defined geographical area

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    By undertaking to act as 'medico necroscopo' (the medical doctors in charge of authorizing every burial) in the Unit\ue0 Socio-Sanitaria Locale (USSL) 70, a region containing 92,500 inhabitants, we were able to collect over a four-year period (1985-88) information on 3371 deaths among residents of the area. Of these, 68.1% died at home, 12.6% in hospital with no autopsy, 9.5% in hospital with an autopsy and 9.8% outside of the USSL region. For the analysis, age, sex and leading cause of death were considered as explanatory variables and place of death and proportion of autopsied cases as the response variables. The factors found to be associated with deaths occurring in hospital were non-neoplastic (particularly cardiovascular and digestive) pathological conditions in patients under the age of 60. People with malignant neoplasms usually died at home, especially when they had a gastric or breast cancer. Factors associated with autopsy were: death at a young age, short length of hospitalization and death from a cardiovascular disease. Sex did not appear to play a direct role in selection for necropsy. Our results indicate that, in our and similar regions, the cases selected for autopsy form a subset that is so specific that any extrapolation to the total deceased population is misleading

    Decreasing incidence of CNS AIDS-defining events associated with antiretroviral therapy.

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    Abstract The authors enrolled 1,029 patients with CD4 counts </= 200/microL and no CNS AIDS-defining events (CNS-AIDS) between January 1993 and December 1998. The primary end point was the first appearance of CNS-AIDS. Three different periods and different antiretroviral regimens were considered. During the median follow-up of 329 days, 144 patients (9.5%) developed CNS-AIDS. The independent predictors were CD4 counts and therapy. All regimens decreased the risk of CNS-AIDS. Highly active antiretroviral therapy led to a 95% risk reduction in comparison with untreated patients

    Estimation of pooled reference values for cadmium in blood using meta-analysis and TRACY criteria

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    Reference values for blood-cadmium levels (B-Cd) are available for only a limited number of geographical areas and for particular population strata (sex, age, smoking habits). This paper, in agreement with the TRACY guidelines, describes and discusses the criteria used to rank published papers on reference values for cadmium retrieved by Medline and Toxline between 1976 and 1991. The TRACY criteria deal with the grading of published papers in terms of their suitability for calculating provisional reference values. Only four out of 18 papers were considered suitable for the TRACY project. The four articles were finally used via meta-analysis to provide provisional reference values for smokers and non-smokers. The comparison of results obtained using published statistics and individual data is used to discuss the appropriateness of meta-analysis in the case of cadmium. Due to the availability of large enough studies and to the clear differences across countries, the suitability of a compound upper reference limit to B-Cd levels seems limited
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