875 research outputs found
Differences in kicking velocity and kicking deficit in young elite soccer players
El objetivo de este estudio fue examinar la evolución del rendimiento máximo de golpeo de balón a lo largo de la edad en futbolistas jóvenes de élite. Un total de 175 fueron divididos en 11 grupos edad (U-9 hasta U-19), además del equipo filial del club (U-23). Se registró la velocidad máxima de golpeo con la pierna dominante y no dominante mediante radar. El déficit de golpeo fue calculado para comparar el rendimiento entre ambas piernas. La velocidad máxima de golpeo aumenta progresivamente de forma significativa desde U-9 hasta U-16 con la pierna dominante y hasta U-18 con la no dominante, y sigue aumentando de forma no significativa hasta U-23. La etapa con mayor incremento de la velocidad de golpeo fue entre U-13 y U-16. Existe un déficit de golpeo con la pierna no dominante y sus valores permanecen estables (9.43%-18.18%) sin cambios significativos desde U-9 hasta U-23The purpose of this current study was to examine the age-related differences in kicking performance with both legs in 175 youth soccer players. Players from the development programme of a professional club were grouped according to their respective under-age team (U-9 to U-18), in addition to the club’s second team (U-23). Maximal kicking velocity with the preferred and non-preferred leg was recorded using a Doppler radar gun. Kicking deficit was calculated to compare side-to-side performance. Maximal kicking velocity improved progressively from the U-9 to U-16 age groups for the preferred leg and from U-16 to U-18 for the non-preferred leg, and continued to improve moderately but non-statistically significant until U-23. The stage of greatest kicking velocity development was between 13 and 16 years of age. There is a kicking deficit with the non-preferred leg and its values remain steady (9.43%-18.18%) without significant changes in players from U-9 to U-23 categorie
Weak first order transition in the three-dimensional site-diluted Ising antiferromagnet in a magnetic field
We perform intensive numerical simulations of the three-dimensional
site-diluted Ising antiferromagnet in a magnetic field at high values of the
external applied field. Even if data for small lattice sizes are compatible
with second-order criticality, the critical behavior of the system shows a
crossover from second-order to first-order behavior for large system sizes,
where signals of latent heat appear. We propose "apparent" critical exponents
for the dependence of some observables with the lattice size for a generic
(disordered) first-order phase transition.Comment: Final version, accepted for publicatio
Optimisation of the extraction and purification of chondroitin sulphate from head by-products of Prionace glauca by environmental friendly processes
8 páginas, 3 figuras, 3 tablasThe goal of the present work was to optimise the different environmental friendly processes involved in the extraction and purification of chondroitin sulphate (CS) from Prionace glauca head wastes. The experimental development was based on second order rotatable designs and evaluated by response surface methodology combined with a previous kinetic approach. The sequential stages optimised were: (1) the enzymatic hydrolysis of head cartilage catalysed by alcalase (55.7 °C/pH 8.2); (2) the chemical treatment of enzyme hydrolysates by means of alkaline-hydroalcoholic saline solutions (NaOH: 0.54 M, EtOH: 1.17 v, NaCl: 2.5%) to end the protein hydrolysis and to precipitate and selectively redissolve CS versus the peptidic material and (3) the selective purification and concentration of CS and the concomitant protein permeation of extracts which were obtained from previous treatment using ultrafiltration and diafiltration (UF–DF) technologies at two different cut-offsFinancial support from projects MARMED 2011-1/164 (Atlantic Area Programme, EU), 0687_NOVOMAR_1_P (POCTEP Programme, EU) and iSEAS LIFE13 ENV/ES/000131 (LIFE+ Programme, EU) is acknowledgedPeer reviewe
Creating functional nanostructures: Encapsulation of caffeine into α-lactalbumin nanotubes
This work evaluated the stability and functionality of nanotubes obtained from α-lactalbumin (α-LA). α-LA nanotubes' structure was highly stable during a freeze-drying process but not after grinding. The ability of α-LA nanotubes to encapsulate caffeine, used as a model molecule, was evaluated. α-La nanotubes were highly effective for this purpose as encapsulation efficiency (%EE) was near 100% and loading capacity (%LC) near 10% at 1.5/20 and 2/20 ratios (caffeine/α-LA, w/w). α-LA nanotubes' structure was not affected by the presence of caffeine. Also, in general, refrigeration temperatures and neutral or alkaline conditions, under which the adverse effect of chelating agents was prevented, helped to stabilise α-LA nanotubes' structure and maintain caffeine encapsulated. At 8 °C and pH 7.5, in the presence of 75 μg mL− 1 of EDTA, > 50% of the caffeine remained encapsulated into α-LA nanotubes.Clara Fuciños gratefully acknowledge her Post-Doctoral grant (I2C 2014) from Consellería de Cultura, Educación e Ordenación Universitaria (Xunta de Galicia, Spain). Pablo Fuciños gratefully acknowledges his Marie Curie COFUND Postdoctoral Research Fellowship (Project No: 600375. NanoTRAINforGrowth - INL Fellowship programme in nanotechnologies for biomedical, environment and food applications). This study was supported by the Fundação para a Ciência e a Tecnologia (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit and COMPETE 2020 (POCI-01-0145-FEDER-006684), and the Project RECI/BBB-EBI/0179/2012 (FCOMP-01-0124-FEDER-027462)
Ureteritis Cystica: Important Consideration in the Differential Diagnosis of Acute Renal Colic
Ureteritis cystica is an uncommon cause of acute renal pain. The aetiology remains unclear and the diagnosis may be difficult to establish. We report the case of a 29 year old woman with a history of repeated urinary tract infections presenting with acute renal colic in the absence of lithiasis. We review the diagnostic tools available to make the diagnosis and the recent pertinent literature
Measures of critical exponents in the four dimensional site percolation
Using finite-size scaling methods we measure the thermal and magnetic exponents of the site percolation in four dimensions, obtaining a value for the anomalous dimension very different from the results found in the literature. We also obtain the leading corrections-to-scaling exponent and, with great accuracy, the critical density
Paraganglioma of Prostatic Origin
Introduction Paragangliomas are usually benign tumors arising from chromaffin cells located outside the adrenal gland. Prostatic paraganglioma is an unusual entity in adult patients, with only 10 cases reported in the medical literature. Case Report A 34-year-old male with a history of chronic prostatitis consulted for perineal pain. On digital rectal examination the prostate was enlarged and firm, without nodules. The PSA level was 0.8 ng/mL and the catecholamines in the urine were elevated. On ultrasound a retrovesical 9 cm mass of undetermined origin measuring was present. A PET-CT scan showed a pelvic lesion measuring 9 cm with moderate increase in glucidic metabolism localized in the area of the prostate. A biopsy of the prostate revealed a neuroendocrine tumor, possibly a prostatic paraganglioma. A body scintigraphy with MIBG I-123 ruled out the presence of metastases or multifocal tumor. A radical prostatectomy with excision of the pelvic mass was performed under adrenergic blockade. One year after surgery the patient is asymptomatic and disease free. Discussion/Conclusions Prostatic paraganglioma is a rare, usually benign tumor, which should be considered in the differential diagnosis of prostate tumors in young males. Its diagnosis is based on the determination of catecholamine in blood and 24-hour urine and in imaging studies principally scintigraphy with MIBG I-123. Diagnostic confirmation is by histopathological study. The treatment consists of radical resection under adrenergic blockade and volume expansion. Given the limited number of cases reported, it is difficult to establish prognostic factors. Malignancy is defined by clinical criteria, and requires life long follow-up
Phase diagram of the (bosonic) Double-Exchange Model
The phase diagram of the simplest approximation to Double-Exchange systems,
the bosonic Double-Exchange model with antiferromagnetic super-exchange
coupling, is fully worked out by means of Monte Carlo simulations, large-N
expansions and Variational Mean-Field calculations. We find a rich phase
diagram, with no first-order phase transitions. The most surprising finding is
the existence of a segment like ordered phase at low temperature for
intermediate AFM coupling which cannot be detected in neutron-scattering
experiments. This is signaled by a maximum (a cusp) in the specific heat. Below
the phase-transition, only short-range ordering would be found in
neutron-scattering. Researchers looking for a Quantum Critical Point in
manganites should be wary of this possibility. Finite-Size Scaling estimates of
critical exponents are presented, although large scaling corrections are
present in the reachable lattice sizes.Comment: 17 pages, 14 figure
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