3,455 research outputs found

    Effetti cardiorespiratori degli sprint ripetuti in giovani calciatori

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    Scopo: Nel calcio la performance dipende da attività caratterizzate da sforzi di breve durata, talora ad alta intensità, con ridotti tempi di recupero. Questo tipo di sforzo può avere maggiore potenzialità aritmogena rispetto a sforzi, anche massimali, iniziati e terminati in modo graduale. Gli sprint ripetuti permettono di valutare la performance e lo stato di allenamento in giovani calciatori. Scopo del nostro lavoro è stato quello di valutare gli effetti degli sprint ripetuti sul sistema cardiorespiratorio in giovani calciatori delle rappresentative regionali siciliane della FIGC. Metodi: Sono stati esaminati 12 calciatori, di età media di 15±1 anni. Per valutare lo stato di fitness cardiorespiratoria sono stati determinati, al test da sforzo incrementale massimale al treadmill (SI), il VO2max in ml.Kg-1.min-1 (VO2maxSI) e la FCmax in bpm (FCmaxSI). Per valutare gli effetti cardiorespiratori degli sprint ripetuti, gli atleti hanno eseguito un test da sforzo al cicloergometro a freno meccanico (SR) che prevedeva 10 sprint massimali “all-out” di 6 sec, intervallati da 30 sec di recupero passivo. Nella serie dei 10 sprint, sono stati determinati il valore più elevato di VO2 in ml.Kg-1.min-1 (VO2maxSR) e di FC in bpm (FCmaxSR). Risultati: Il valore medio di VO2maxSI (56,22±3,93 ml.Kg-1.min-1) indica che i soggetti esaminati hanno un buon livello di potenza aerobica, raggiunta ad una FCmaxSI di 190±8 bpm. I dati di VO2maxSR rilevati al test degli sprint ripetuti evidenziano un valore medio di 42,67±5,57 ml.Kg-1.min-1 (70% del VO2maxSI), raggiunto ad una FCmaxSR di 175±11 bpm (92% della FCmaxSI). Conclusioni: I dati del nostro studio indicano che nei soggetti esaminati gli sprint ripetuti determinano incrementi della frequenza cardiaca rapidi, elevati e persistenti nella fase di recupero. Questo dato deve essere preso in considerazione non solo per la valutazione della performance ma anche nella formulazione dell’idoneità a praticare la disciplina sportiva del calcio

    Interacting Kasner-type cosmologies

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    It is well known that Kasner-type cosmologies provide a useful framework for analyzing the three-dimensional anisotropic expansion because of the simplification of the anisotropic dynamics. In this paper relativistic multi-fluid Kasner-type scenarios are studied. We first consider the general case of a superposition of two ideal cosmic fluids, as well as the particular cases of non-interacting and interacting ones, by introducing a phenomenological coupling function q(t)q(t). For two-fluid cosmological scenarios there exist only cosmological scaling solutions, while for three-fluid configurations there exist not only cosmological scaling ones, but also more general solutions. In the case of triply interacting cosmic fluids we can have energy transfer from two fluids to a third one, or energy transfer from one cosmic fluid to the other two. It is shown that by requiring the positivity of energy densities there always is a matter component which violates the dominant energy condition in this kind of anisotropic cosmological scenarios.Comment: Accepted for publication in Astrophysics &Space Science, 8 page

    Higher dimensional gravity invariant under the Poincare group

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    It is shown that the Stelle-West Grignani-Nardelli-formalism allows, both when odd dimensions and when even dimensions are considered, constructing actions for higher dimensional gravity invariant under local Lorentz rotations and under local Poincar\`{e} translations. It is also proved that such actions have the same coefficients as those obtained by Troncoso and Zanelli in ref. Class. Quantum Grav. 17 (2000) 4451.Comment: 7 pages, Latex, accepted in Phys. Rev.

    Magnetically charged solutions via an analog of the electric-magnetic duality in (2+1)-dimensional gravity theories

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    We find an analog of the electric-magnetic duality, which is a Z2Z_2 transformation between magnetic and electric sectors of the static and rotationally symmetric solutions in a class of (2+1)-dimensional Einstein-Maxwell-Dilaton gravity theories. The theories in our consideration include, in particular, one parameter class of theories continuously connecting the Banados-Teitelboim-Zanelli (BTZ) gravity and the low energy string effective theory. When there is no U(1)U(1) charge, we have O(2)O(2) or O(1,1)O(1,1) symmetry, depending on a parameter that specifies each theory. Via the Z2Z_2 transformation, we obtain exact magnetically charged solutions from the known electrically charged solutions. We explain the relationship between the Z2Z_2 transformation and O(2,Z)O(2,Z) symmetry, and comment on the TT-duality of the string theory.Comment: 10 pages, RevTe

    Comparison of screening tools for the detection of neurocognitive impairment in HAART-treated patients

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    Background: Neurocognitive impairment (NCI) and HIV-associated neurocognitive disorders (HAND) remain prevalent despite HAART. We examined sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and correct classification rate (CCR) of screening tools for the detection of NCI and HAND in HAART treated patients. Methods: We examined 101 unselected HAART-treated patients. Patients were administered the self-reported three questions (EACS Guidelines), the International HIV-Dementia Scale (IHDS), the Mini-Mental Status Examination (MMSE), and a comprehensive 6-domain (17-test) neuropsychological (NP) battery (120 minutes) that included, among others, the Digit Symbol (DS), the Trail Making Modalities (TM), and the Grooved Pegboard (GP) tests. NCI was defined according to the AAN criteria. HAND was diagnosed after exclusion of confounding conditions. Results: Our cohort was relatively healthy (mean CD4 count: 575 cells/mm3, undetectable plasma HIV RNA 85%). Prevalence of NCI and HAND were 39.6% (40 of 101) and 30.7% (31 of 101), respectively. Mean scores of IHDS (9.9 vs 10.8; p<0.001) and MMSE (26.8 vs 28.2; p=0.004) differed significantly between impaired and unimpaired patients, while mean three-questions scores (8.0 vs 7.0; p=0.23) did not. The three questions showed also poor sensitivity for the detection of both NCI (20%) and HAND (22%). The IHDS showed fairly good sensitivity (55%) and NPV (73.5%). Adding to the IHDS some easy to administer NP tests, i.e. TM, DS, and GP, resulted in an increase in sensitivity and NPV for the detection of NCI (table). Similar results were obtained regarding the detection of HAND (not shown in table). Conclusions: Both NCI and HAND are still very prevalent in HAART-treated patients. Among screening tools the self-reported three question show poor sensitivity. The IHDS performed better in terms of sensitivity, PPV, and NPV. Combinations of easy-to-administer NP tests with the IHDS resulted in increased sensitivity and NPV. Combining IHDS with one or two simple NP test may represent an improvement in the screening approach to the detection of both NCI and HAND

    VHMPID: a new detector for the ALICE experiment at LHC

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    This article presents the basic idea of VHMPID, an upgrade detector for the ALICE experiment at LHC, CERN. The main goal of this detector is to extend the particle identification capabilities of ALICE to give more insight into the evolution of the hot and dense matter created in Pb-Pb collisions. Starting from the physics motivations and working principles the challenges and current status of development is detailed.Comment: 4 pages, 6 figures. To be published in EPJ Web of Conference

    No Black Hole Theorem in Three-Dimensional Gravity

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    A common property of known black hole solutions in (2+1)-dimensional gravity is that they require a negative cosmological constant. In this letter, it is shown that a (2+1)-dimensional gravity theory which satisfies the dominant energy condition forbids the existence of a black hole to explain the above situation.Comment: 3 pages, no figures, to be published in Physical Review Letter

    Serological survey and molecular characterization of theileria annulata in sicilian cattle

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    Tropical theileriosis is a tick-borne disease caused by hemoprotozoan parasites with considerable veterinary and economic impact worldwide. Ticks transmitting the disease belong to the Haemaphysalis, Rhipicephalus, and Hyalomma genera. The Hyalomma genus is very common in Sicily (Italy) and represents the main Theileria annulata vector in the island. Data concerning the molecular epidemiology of this pathogen are missing in the region. In 2018–2019, blood and serum samples were collected from 480 cows in seven Sicilian farms from four different provinces. Seroprevalence in the farms ranged from 22% to 71%. Three farms were selected for molecular analysis consisting of real-time PCR targeting the almost complete 18S ribosomal RNA (rRNA). Four amplicons per farm were sequenced and phylogenetic analyses were carried out. The four sequences were identical within each farm and showed 92–99% identity with the other farms and with sequences from Genbank. According to the phylogenetic analysis, these three sequences and an additional one from a laboratory-cultured Theileria annulata strain obtained in 1999 belonged to a single T. annulata clade with good bootstrap support with other sequences from Italy, India, and Iran, indicating limited geographical and temporal genetic variability of the parasite. This study represents the first phylogenetic analysis of T. annulata in Sicily, which will be useful to improve the strategies for theileriosis control and prevention

    The role of ultrasound guided sampling procedures in the diagnosis of pelvic masses: A narrative review of the literature

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    Ultrasound-guided sampling methods are usually minimally invasive techniques applied to obtain cytological specimens or tissue samples, mainly used for the diagnosis of different types of tumors. The main benefits of ultrasound guidance is its availability. It offers high flexibility in the choice of sampling approach (transabdominal, transvaginal, and transrectal) and short duration of procedure. Ultrasound guided sampling of pelvic masses represents the diagnostic method of choice in selected patients. We carried out a narrative review of literatures regarding the ultrasound-guided methods of cytological and histological evaluation of pelvic masses as well as the positive and negative predictors for the achievement of an adequate sample

    The Importance of Mehran Score to Predict Acute Kidney Injury in Patients with TAVI: A Large Multicenter Cohort Study

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    Background: Transcatheter aortic valve implantation (TAVI) has developed as an alternative to surgery for symptomatic high-risk patients with aortic stenosis (AS). An important complication of TAVI is acute kidney injury. The purpose of the study was to investigate if the Mehran Score (MS) could be used to predict acute kidney injury (AKI) in TAVI patients. Methods: This is a multicenter, retrospective, observational study including 1180 patients with severe AS. The MS comprised eight clinical and procedural variables: hypotension, congestive heart failure class, glomerular filtration rate, diabetes, age >75 years, anemia, need for intra-aortic balloon pump, and contrast agent volume use. We assessed the sensitivity and specificity of the MS in predicting AKI following TAVI, as well as the predictive value of MS with each AKI-related characteristic. Results: Patients were categorized into four risk groups based on MS: low (≤5), moderate (6–10), high (11–15), and very high (≥16). Post-procedural AKI was observed in 139 patients (11.8%). MS classes had a higher risk of AKI in the multivariate analysis (HR 1.38, 95% CI, 1.43–1.63, p < 0.01). The best cutoff for MS to predict the onset of AKI was 13.0 (AUC, 0.62; 95% CI, 0.57–0.67), whereas the best cutoff for eGFR was 42.0 mL/min/1.73 m2 (AUC, 0.61; 95% CI, 0.56–0.67). Conclusions: MS was shown to be a predictor of AKI development in TAVI patients
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