1,720,958 research outputs found
Rapid weight gain in professional boxing and correlation with fight decisions: analysis from 71 title fights
No full textOBJECTIVES:
Boxing is a sport where athletes compete in several weight categories. Professional boxers typically dehydrate to cut their weight for the weigh-in (24 h before the contest) and then rehydrate before the fight. The International Boxing Federation (IBF) mandates a second weigh-in 12 h before the fight. Our objectives were: 1) To quantify the weight gain (WG) from the 1st to the 2nd weigh-in; 2) to investigate whether rapid WG affects boxing performance (win/loss rate) and 3) whether weight discrepancy (WD) 15 between boxers exposes them to increased health risks (rate of fights ended before time limit).
METHODS:
From official weigh-in reports of 71 IBF fights (142 fighters) the following data were gathered/calculated for each boxer: age, weight division, 1st weight, 2nd weight, WG between weigh-ins (kg and %), WD between opponents, and fight decision.
RESULTS:
Between the weigh-ins, the average WG was 2.52 ± 1.37 kg (range -0.3/6.4 kg) and 3.8 ± 2.2% of the initial body weight (range -0.4/9.3%) and the average WD 1.94 ± 1.50 kg (maximum 7.10 kg). Both WG and WD did not affect match outcomes. We observed tendencies for higher loss rate among boxers gaining more weight, and for higher victory rate in boxers with larger WD, however without reaching significance. A significant negative correlation was found between the 1st weight and the WG, both in absolute (r = -0.278, p = 0.001) and relative value (r = -0.497, p < 0.0001).
CONCLUSIONS:
Although correlations between WG, WD and boxing performance were not found, single cases with an alarming high WG and WD were noted
Una rara causa di dispnea acuta durante competizione agonistica: pneumomediastino spontaneo in giocatore di pallavolo.
No full textUn giovane praticante pallavolo a livello agonistico, durante una partita, avverte improvvisamente
un forte dolore toracico con dispnea, in assenza di colpi subiti o traumi, che si aggrava fino
a diventare ingravescente e richiedere l’accesso in pronto soccorso. Dopo i primi accertamenti
maggiormente indirizzati ad escludere cause cardiache, tramite esami di imaging si identifica la
causa della sintomatologia in pneumomediastino spontaneo, in assenza di pneumotorace associato.
Il complesso meccanismo fisiopatologico alla base del problema è il cosiddetto meccanismo di
Hamman-Macklin, (che viene illustrato e dimostrato per esteso nelle slides della comunicazione
orale). Dopo la risoluzione del quadro clinico e la normalizzazione dei profili radiografici, persiste
tuttavia anche a mesi di distanza una dispnea da sforzo fisico, di difficile interpretazione diagnostica.
Diverse ipotesi diagnostiche ed esami vengono effettuati; l’iter è mostrato nella comunicazione
orale. NB immagini RX e TC sono mostrate durante la presentazione, con spiegazione dei segni patognomonici dello pneumomediastino, prima e dopo risoluzione
Amateur boxing in the last 59 years. Impact of rules changes on the type of verdicts recorded and implications on boxers' health
No full textAbstract
BACKGROUND/AIM: Several changes have occurred in Olympic boxing (OB) in the last few decades, influencing the results in official competitions. The aim of this study was to assess how the evolution of rules changed the rate of the results that can influence boxers' health.
METHODS: From a web-research, the results of OB tournaments from 1952 to 2011 were reviewed (29 357 bouts). For each event, rate of knockout (KO), referee-stop contest (RSC), RSC-Head (RSCH), RSC-Injury (RSCI), RSC-Outclassed (RSCO), abandon, disqualification and points decisions were recorded. In our analysis we investigated the changes that occurred after the introduction of the standing-count rule (1964), mandatory head guard (1984), computerised scoring system (1992), RSCO (2000-2009) and modification of bout formula 3×3 min rounds (3×3, until 1997, 5×2 min rounds (5×2) until 1999, 4×2 min rounds (4×2) until 2008, 3×3 from 2009).
RESULTS: The most important results were: (1) an RSCI rate increase (0.72-2.42%, p<0.03) after the standing-count rule; (2) a lower RSCI (0.60%, p<0.001) and higher RSCH (1.31-4.92%, p<0.001) and RSC (9.71-13.05%, p<0.03) rate with mandatory head guard; (3) a KO rate reduction (6.44-2.09%, p<0.001) with the computerised scoring system; (4) an RSC (13.15-5.91%, p<0.05) and RSCH (4.23-1.41%, p<0.001) rate reduction comparing 5×2-4×2 bouts.
CONCLUSIONS: In the last six decades, along with rule changes in OB, a clear reduction of health challenging results was observed. In the near future, older rules will be adopted (no head guard and a manual scoring system). Continued medical surveillance is important to ensure that new rule changes do not result in poor medical outcomes for the boxers
Heart and Brain:Complex Relationships for Left Ventricular Dysfunction
No full textPurpose of Review: This review summarizes the evidence for the established vascular/hypoperfusion model and explores the new hypothesis that configures the heart/brain axis as an organ system where similar pathogenic mechanisms exploit physiological and pathological changes. Recent Findings: Although associated by common risk factors, similar epidemiological stratification and common triggers (including inflammation, oxidative stress, and hypoxia), heart failure and Alzheimer’s disease have been, for long time, viewed as pathogenically separate illnesses. The silos began to be broken down with the awareness that vascular dysfunction, and loss of cardiac perfusion pump power, trigger biochemical changes, contributing to the typical hallmark of Alzheimer’s disease (AD)—the accumulation of Aβ plaques and hyperphosphorylated Tau tangles. Compromised blood flow to the brain becomes the paradigm for the “heart-to-head” connection. Compelling evidence of common genetic variants, biochemical characteristics, and the accumulation of Aβ outside the brain suggests a common pathogenesis for heart failure (HF) and AD. These new findings represent just the beginning of the understanding the complex connection between AD and HF requiring further studies and interdisciplinary approaches. Summary: Altogether, the current evidence briefly summarized in this review, highlight a closer and complex relationship between heart failure and Alzheimer’s that goes beyond the vascular/perfusion hypothesis. Genetic and biochemical evidence begin to suggest common pathogenic mechanisms between the two diseases involving a systemic defect in the folding of protein or a seeding at distance of the misfolded proteins from one organ to the other.</p
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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