3,460 research outputs found

    Clustering by fast search-and-find of density peaks

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    Cluster analysis is aimed at classifying elements into categories on the basis of their similarity. Its applications range from astronomy to bioinformatics, bibliometrics, and pattern recognition.We propose an approach based on the idea that cluster centers are characterized by a higher density than their neighbors and by a relatively large distance from points with higher densities. This idea forms the basis of a clustering procedure in which the number of clusters arises intuitively, outliers are automatically spotted and excluded fromthe analysis, and clusters are recognized regardless of their shape and of the dimensionality of the space inwhich they are embedded.We demonstrate the power of the algorithm on several test cases

    Swimming training repercussion on metabolic and structural bone development; benefits of the incorporation of whole body vibration or pilometric training; the RENACIMIENTO project

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    Introduction: Enviromental factors such as exercise participation and nutrition have often been linked to bone improvements. However, not all sports have the same effects, being non-osteogenic sports such as swimming defined as negative or neutral sports to practice regarding bone mass by some authors, similarly exercise-diet interaction in especific groups is still not clear. Objective: To present the methodology of the RENACIMENTO project that aims to evaluate body composition and more specifically bone mass by several techniques in adolescent swimmers and to observe the effects and perdurability of whole body vibration (WBV) and jumping intervention (JIN) on body composition and fitness on this population and explore posible diet interactions. Design: Randomized controlled trial. Methods: 78 swimmers (12-17 y) and 26 sex- and age-matched controls will participate in this study. Dual energy X-ray, peripheral Quantitative Computed Tomography, Quantitative Ultrasound, Bioelectrical Impedance Analysis, and anthropometry measurements will be performed in order to evaluate body composition. Physical activity, nutrition, pubertal development and socio-economical status may act as confounders of body composition and therefore will also be registered. Several fitness factors regarding strength, endurance, performance and others will also be registered to evaluate differences with controls and act as confounders. A 7-month WBV therapy will be performed by 26 swimmers consisting of a training of 15 minutes 3 times per week. An 8 month JIM will also be performed by 26 swimmers 3 times per week. The remaining 26 swimmers will continue their normal swimming training. Four evaluations will be performed, the first one in order to describe differences between swimmers and controls. The second one to describe the effects of the interventions and the third and fourth evaluations to describe the perdurability of the effects of the WBV and JIN. Conclusion: The RENACIMIENTO project will allow to answer several questions regarding body composition, fitness, bone mass and interaction with diet of adolescent swimmers, describe swimming as a positive, negative or neutral sport to practice regarding these parameters and elucidate the effects and perdurability of WBV and JIM on body composition

    Photometry Results for the Globular Clusters M10 and M12: Extinction Maps, Color-Magnitude Diagrams, and Variable Star Candidates

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    We report on photometry results of the equatorial globular clusters (GCs) M10 and M12. These two clusters are part of our sample of GCs which we are probing for the existence of photometrically varying eclipsing binary stars. During the search for binaries in M10 and M12, we discovered the signature of differential reddening across the fields of the clusters. The effect is stronger for M10 than for M12. Using our previously described dereddening technique, we create differential extinction maps for the clusters which dramatically improve the appearance of the color-magnitude diagrams (CMDs). Comparison of our maps with the dust emissivity maps of Schlegel, Finkbeiner, & Davis (SFD) shows good agreement in terms of spatial extinction features. Several methods of adding an E_{V-I} zero point to our differential maps are presented of which isochrone fitting proved to be the most successful. Our E_{V-I} values fall within the range of widely varying literature values. More specifically, our reddening zero point estimate for M12 agrees well with the SFD estimate, whereas the one for M10 falls below the SFD value. Our search for variable stars in the clusters produced a total of five variables: three in M10 and two in M12. The M10 variables include a binary system of the W Ursa Majoris (W UMa) type, a background RR Lyrae star, and an SX Phoenicis pulsator, none of which is physically associated with M10. M12's variables are two W UMa binaries, one of which is most likely a member of the cluster. We present the phased photometry lightcurves for the variable stars, estimate their distances, and show their locations in the fields and the CMDs of the GCs.Comment: 22 pages, 21 figures, to be published in AJ October 2002. For a higher-resolution version of this paper, please visit http://www.astro.lsa.umich.edu/~kaspar/M10_M12_photometry.ps.gz (gzipped postscript) or http://www.astro.lsa.umich.edu/~kaspar/M10_M12_photometry.pdf (pdf file

    The GenusAlistipes:Gut Bacteria With Emerging Implications to Inflammation, Cancer, and Mental Health

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    Alistipesis a relatively new genus of bacteria isolated primarily from medical clinical samples, although at a low rate compared to other genus members of theBacteroidetesphylum, which are highly relevant in dysbiosis and disease. According to the taxonomy database at The National Center for Biotechnology Information, the genus consists of 13 species:Alistipes finegoldii, Alistipes putredinis, Alistipes onderdonkii, Alistipes shahii, Alistipes indistinctus, Alistipes senegalensis, Alistipes timonensis, Alistipes obesi, Alistipes ihumii, Alistipes inops, Alistipes megaguti, Alistipes provencensis, andAlistipes massiliensis. Alistipes communisandA. dispar, and the subspeciesA. Onderdonkiisubspecies vulgaris (vs.onderdonkiisubsp.) are the newest strains featured outside that list. Although typically isolated from the human gut microbiome various species of this genus have been isolated from patients suffering from appendicitis, and abdominal and rectal abscess. It is possible that asAlistipesspp. emerge, their identification in clinical samples may be underrepresented as novel MS-TOF methods may not be fully capable to discriminate distinct species as separate since it will require the upgrading of MS-TOF identification databases. In terms of pathogenicity, there is contrasting evidence indicating thatAlistipesmay have protective effects against some diseases, including liver fibrosis, colitis, cancer immunotherapy, and cardiovascular disease. In contrast, other studies indicateAlistipesis pathogenic in colorectal cancer and is associated with mental signs of depression. Gut dysbiosis seems to play a role in determining the compositional abundance ofAlistipesin the feces (e.g., in non-alcoholic steatohepatitis, hepatic encephalopathy, and liver fibrosis). SinceAlistipesis a relatively recent sub-branch genus of theBacteroidetesphylum, and sinceBacteroidetesare commonly associated with chronic intestinal inflammation, this narrative review illustrates emerging immunological and mechanistic implications by whichAlistipesspp. correlate with human health

    Influence of different playing surfaces on bone mass accretion in male adolescent football players: A one-season study

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    There are different surfaces on which football is played, but their influence on bone mass accretion still remains unknown. The aims of this study were to compare bone mass accretion between football players and controls, and evaluate the influence of two different playing surfaces on bone accretion. A total of 27 male football players (13.2 +/- 0.5 years) and 15 controls (12.6 +/- 1.1 years) participated in this study. Football players were classified into two groups according to the surface they trained on: 14 on third-generation artificial turf with elastic layer and 13 on third-generation artificial turf without elastic layer. Bone mineral content and areal bone mineral density were measured using dual-energy X-ray absorptiometry. Bone mineral apparent density variables were calculated. Bone geometry and strength of the non-dominant tibia were assessed with peripheral quantitative computed tomography. For both football players and controls, bone variables measured at subtotal body, lumbar spine, legs and tibia (p < 0.05) significantly increased. Based on the time spent practicing football, the increase in areal bone mineral density for the legs (p < 0.05) was higher in football players than controls. Moreover, lumbar spine bone mineral apparent density increased more in third-generation artificial turf without elastic layer players in comparison with third-generation artificial turf with elastic layer players (p < 0.05). Playing football on third-generation artificial turf with elastic layer and third-generation artificial turf without elastic layer seems to positively affect bone mass during growth. After playing for one season on these playing surfaces, football practice on third-generation artificial turf without elastic layer with the lower shock absorption seems to have produced the highest increment in areal bone mineral density at lumbar spine. Thus, football practice on surfaces with lower shock absorption could provide an extra benefit on bone health

    Effect of aerobic exercise on waist circumference in adults with overweight or obesity : a systematic review and meta-analysis

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    Excess visceral adiposity contributes to elevated cardiometabolic risk, and waist circumference is commonly used as a surrogate measure of visceral adipose tissue. Although regular aerobic exercise is known to improve abdominal obesity, its effect on waist circumference is unclear. A systematic review and meta-analysis was performed to determine (1) the effect of aerobic exercise on waist circumference in adults with overweight or obesity; (2) the association between any change in waist circumference and change in visceral adipose tissue and/or bodyweight with aerobic exercise interventions; and (3) if reductions in waist circumference with exercise are moderated by clinical characteristics or components of aerobic exercise prescription. Twenty-five randomized controlled trials (1686 participants) were included. Regular aerobic exercise significantly reduced waist circumference by 3.2 cm (95% confidence interval [CI] −3.86, −2.51, p ≤ 0.001) versus control. Change in waist circumference was associated with change in visceral adipose tissue (β = 4.02; 95% CI 1.37, 6.66, p = 0.004), and vigorous intensity produced superior reduction (−4.2 cm, 95% CI −4.99, −3.42, p < 0.0001) in waist circumference compared with moderate intensity (−2.50 cm, 95% CI −3.22, −1.79, p = 0.058). These findings suggest regular aerobic exercise results in modest reductions in waist circumference and associated visceral adipose tissue and that higher intensity exercise may offer superior benefit to moderate intensity

    Joint effect of physical activity and sedentary behaviour on cardiovascular risk factors in Chilean adults

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    Background: To investigate the associations between combined categories of moderate-to-vigorous physical activity (MVPA) and sedentary behaviour (SB) with markers of adiposity and cardiovascular risk in adults. Methods: Overall, 5040 participants (mean age 46.4 years and 59.3% women) from the cross-sectional Chilean National Health Survey 2009–2010 were included in this study. MVPA and SB were measured using the Global Physical Activity questionnaire. Four categories were computed using MVPA- and SB-specific cut-offs (‘High-SB &#38; Active’, ‘Low-SB &#38; Active’, ‘High-SB &#38; Inactive’ and ‘Low-SB &#38; Inactive’). Results: Compared to the reference group (‘High-SB &#38; Inactive’), those in ‘High-SB &#38; Active’ and ‘Low-SB &#38; Active’ were less likely to have an obese BMI (OR: 0.67 [0.54; 0.85], P = 0.0001 and 0.74 [0.59; 0.92] P = 0.0007, respectively) and less likely to have metabolic syndrome (OR: 0.63 [0.49; 0.82], P &lt; 0.0001 and 0.72 [0.57; 0.91], P = 0.007), central obesity (OR: 0.79 [0.65; 0.96], P = 0.016 and 0.71 [0.59; 0.84], P &lt; 0.0001), diabetes (OR: 0.45 [0.35; 0.59], P &lt; 0.0001 and 0.44 [0.34; 0.56], P &lt; 0.0001) and hypertension (OR: 0.52 [0.43; 0.63], P &lt; 0.0001 and 0.60 [0.50; 0.72], P &lt; 0.0001), respectively. Conclusions: Being physically active and spending less time in SBs was associated with lower adiposity and improvements in cardiovascular risk factors

    Lesiones cerebrales captantes de gadolinio en el brote de los pacientes con esclerosis múltiple

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    Esclerosis múltiple; Brote; Resonancia magnéticaEsclerosi múltiple; Brot; Imatge per ressonància magnèticaMultiple sclerosis; Outbreak; Magnetic resonance imagingObjective To study the clinico-radiological paradox in multiple sclerosis (MS) relapse by analyzing the number and location of gadolinium-enhanced (Gd+) lesions on brain MRI before methylprednisolone (MP) treatment. Methods We analyzed brain MRI from 90 relapsed MS patients in two Phase IV multicenter double-blind randomized clinical trials that showed the noninferiority of different routes and doses of MP administration. A 1.5- or 3-T brain MRI was performed at baseline before MP treatment and within 15 days of symptom onset. The number and location of Gd+ lesions were analyzed. Associations were studied using univariate analysis. Results Sixty-two percent of patients had at least 1 Gd+ brain lesion; the median number was 1 (interquartile range 0–4), and 41% of patients had 2 or more lesions. The most frequent location of Gd+ lesions was subcortical (41.4%). Gd+ brain lesions were found in 71.4% of patients with brainstem-cerebellum symptoms, 57.1% with spinal cord symptoms and 55.5% with optic neuritis (ON). Thirty percent of patients with brain symptoms did not have Gd+ lesions, and only 43.6% of patients had symptomatic Gd+ lesions. The univariate analysis showed a negative correlation between age and the number of Gd+ lesions (p = 0.002). Conclusion Most patients with relapse showed several Gd+ lesions on brain MRI, even when the clinical manifestation was outside of the brain. Our findings illustrate the clinico-radiological paradox in MS relapse and support the value of brain MRI in this scenario.Objetivo Estudiar la paradoja clínico-radiológica en el brote de la esclerosis múltiple (EM) mediante el análisis de lesiones captantes de gadolinio (Gd+) en la RM cerebral antes del tratamiento con metilprednisolona (MP). Métodos Analizamos la RM cerebral basal de 90 pacientes con EM en brote de 2 ensayos clínicos aleatorizados multicéntricos fase IV que demostraron la no inferioridad de diferentes vías y dosis de MP, realizadas antes del tratamiento con MP y en los 15 días siguientes a la aparición de los síntomas. Se analizaron el número y la localización de las lesiones Gd+. Se estudiaron las asociaciones mediante análisis univariado. Resultados El 62% de los pacientes tenía al menos una lesión Gd+ cerebral y el 41% de los pacientes tenía 2 o más lesiones. La localización más frecuente fue la subcortical (41,4%). Se encontraron lesiones Gd+ cerebrales en el 71,4% de los pacientes con síntomas de tronco cerebral o cerebelo, en el 57,1% con síntomas medulares y en el 55,5% con neuritis óptica. El 30% de los pacientes con síntomas cerebrales no tenían lesiones Gd+ y sólo el 4,.6% de los pacientes tenían lesiones Gd+ sintomáticas. El análisis univariante mostró una correlación negativa entre la edad y el número de lesiones Gd+ (p = 0,002). Conclusiones La mayoría de los pacientes en brote mostraron varias lesiones Gd+ en la RM cerebral, incluso cuando la manifestación clínica fue medular u óptica. Nuestros hallazgos ilustran la paradoja clínico-radiológica en el brote de la EM y apoyan el valor de la RM cerebral en este escenario.This work was supported in part by the Ministry of Health of Spain (grant numbers EC07/90278 and EC11/132) and personal grant Rio Hortega CM19/00042 to LMA

    Validity and reliability of an optoelectronic system to measure movement velocity during bench press and half squat in a Smith machine

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    The purpose of this study was to determine the validity and reliability of a camera-based optoelectronic system to measure movement velocity during bench press and half squat at different load intensities. A total of 22 active males (age: 28.2 +/- 3.9 years; one-repetition maximum bench press: 77.9 +/- 19.0 kg; one-repetition maximum half squat: 116.6 +/- 22.5 kg) participated in this study. After an initial one-repetition maximum testing session, participants performed five repetitions for each load (40%, 60% and 80% one-repetition maximum) and exercise (bench press and half squat) on a Smith machine in the second testing session. A third testing session was used for the test-retest reliability study. Time, displacement and mean propulsive velocity were simultaneously determined by the reference method (T-Force system) and the Velowin system. In bench press, ordinary least products regression analysis revealed low fixed biases for mean propulsive velocity at 40%, time at 60% and displacement at 80% one-repetition maximum (intercept = 0.065 m s(-1), -28.02 ms and 0.87 cm, respectively). In half squat, low fixed biases were also detected for mean propulsive velocity at 40% and 80% one-repetition maximum (intercept = -0.040 and 0.023 m s(-1), respectively), time at 40% and 60% one-repetition maximum (intercept = -53.05 and -101.85 ms, respectively) and displacement at 60% one-repetition maximum (intercept = -1.95 cm). Proportional bias was only observed for mean propulsive velocity at 80% bench press. In half squat, there was proportional bias for time and mean propulsive velocity at 40% one-repetition maximum, and also for time at 60% one-repetition maximum. The reliability test showed low and comparable fixed and proportional biases between systems across exercises and intensities. Velowin confirmed to be a valid and reliable system to measure movement velocity across a wide range of intensities (40%-80% one-repetition maximum) for two basic strength exercises through a robust statistical approach. Velowin would provide coaches and trainers with a suitable, affordable and easy-to-use equipment capable of measuring movement velocity in various exercises at different load intensities

    Timing of Increment Formation in Atlantic Bluefin Tuna (Thunnus thynnus) Otoliths.

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    Controversies remain regarding the periodicity, or seasonality, of otolith growth band formation, which directly influences a correct age determination of Atlantic bluefin tuna using this structure. The aim of this work was to apply marginal increment analysis and marginal edge analysis to determine the timing of band deposition. The index of completion was analyzed using general additive models to evaluate the importance of variables, such as month, age/size, and reader. Results indicate that the opaque band formation begins in June and is completed by the end of November. From the end of the year to the beginning of the following year, there is minimal marginal edge growth as the translucent band begins to form. The translucent zone then reaches a maximum development in May. The results obtained in this study provide evidence that the annulus formation in the otoliths of Atlantic bluefin tuna are completed later in the calendar year than previously thought. This would mean it is necessary to delay the date of the current July 1st adjustment criterion to November 30
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