612 research outputs found
Estudio de dos propuestas sobre el modelo «phantom» de proporcionalidad de Ross y Wilson
El modelo «Phantom» de proporcionalidad de Ross y Wilson (1974) plantea dificultades cuando se trata de evaluar la proporcionalidad de individuos cuyos patrones normales se alejan de los promedios estándar poblacionales; muy especialmente en deportistas de élite o individuos en fase de crecimiento. Por este motivo, en los últimos años han aparecido propuestas de variación sobre el modelo «Phantom», como el Método Combinado propuesto por Lentini (2004) y el Método Escalable propuesto por nuestro grupo de investigación en 2005. En el presente artículo se hace un estudio comparativo de ambos métodos.
The proportionality «Phantom» model of Ross and Wilson (1974) creates difficulties for evaluate the proportionality of individuals whose normal patrons are outside the population averages standard; very especially for elite athlete or individuals in growth phase. For this reason, in the last years, proposals of variation on the «Phantom» model have appeared, such as the Combined Method proposed by Lentini (2004) and the Scalable Method proposed by our rechearch team in 2005. The present article is a comparative study of both methods
Cambios de la proporcionalidad corporal durante el crecimiento en edades adolescentes
La adolescencia es una etapa crítica de la ontogenia caracterizada por importantes cambios en la velocidad de crecimiento de los tejidos que afectan al tamaño, forma y composición corporal, lo que origina profundas diferencias alométricas entre los individuos según el sexo y estadío madurativo. El presente estudio aborda la valoración del grado de madurez, como índice de salud del adolescente, en función de los índices Z del modelo estándar de proporcionalidad corporal conocido como «Phantom», que representa al promedio poblacional adulto. Aplicando el método antropométrico, se analiza una muestra de 360 adolescentes, entre 10 y 15 años y se encuentra que hacia edades más avanzadas los índices Z de las distintas variables antropométricas se aproximan mejor a los valores del Phantom, hallándose diferencias en la progresión de dichos índices según el sexo, por lo que se debate la adecuación de éste modelo a la interpretación de la realidad cambiante del cuerpo humano
Estimación del grado de desarrollo de la composición corporal en deportistas púberes y prepúberes
Un valioso elemento en la vigilancia de la salud pediátrica es la gráfica de recimiento, que relaciona en curvas de percentil la edad con el peso y la talla. Bastante útiles en edades preescolares, son poco representativas de los cambios producidos en etapas adolescentes en las que se añade al crecimiento normal, los cambios fisiológicos propios del desarrollo puberal y factores
ambientales tales como la practica de actividades deportivas, que pueden inducir un desarrollo diferente de cada componente corporal.
Aplicando el método antropométrico se calcula la composición corporal de 300 escolares
entre 10 y 15 años, estudiando el fraccionamiento del peso corporal en 4 componentes. Los objetivos
del presente estudio son: conocer cómo cambian los distintos componentes corporales durante
las etapas preadolescente y adolescente de los individuos que realizan deporte
extraescolar y obtener gráficas de crecimiento para cada componente similares a las existentes
para la correlación edad/peso, edad/talla, peso/talla aceptadas por la OMS y de idéntico manejo,
que muestren las variables en percentiles por edad, no en términos de proporción del peso
total, sino en valor absoluto para cada componente, de modo que permitan monitorizar el desarrollo
de cada individuo, resultando así de utilidad en la práctica clínica diaria.Los resultados
de la artroplastia de codo han mejorado sustancialmente coincidiendo con el mejor conocimiento
de la biomecánica del codo. El diseño y los resultados clínicos de las prótesis de codo se basan
en un conocimiento preciso de la cinemática, los estabilizadores y las fuerzas que atraviesan
esta articulación.A valuable element in the vigilance of the pediatric health is the graph of growth which relates in curves of percentile the age with the weight and the height. Very useful in preschool ages, they are not very representative in the changes of the adolescent stages in which, to the normal growth, it adds the physiologic changes characteristic of the development puberal and environmental factors just as practice of sport activities that can induce a different development in each corporal component.
Applying the anthropometric method, the body composition of 300 scholars, between 10 and
15 years old, is calculated, studying the division of the corporal mass according to four
compartment model. The objectives of the present study are: to know the change of the different
corporal components during the preadolescent and adolescent stages of the people whom
practice extra-school sport and to obtain graphics of growth for each component similar to the
existent ones for the correlation age/weight, age/height, weight/height accepted by the WHO and
of identical handling that show the variables in percentiles for age, not in terms of proportion of
the total weight, but in absolute value for each component, so they allow to monitor the
development of each person, being that utility in the everyday clinical practice
Municipal wastewater can result in a dramatic decline in freshwater fishes: a lesson from a developing country
Impacts of ineffective wastewater management on the biodiversity of receiving waters in developing countries are poorly documented. Using a before-after-control-impact methodology, we measured the effects of untreated wastewater release on the fish community in the Barnoi River, Bangladesh. In 2006, prior to untreated wastewater discharge, fish abundance, species richness and water quality were similar across sampling sites. In 2016, after 8 years of wastewater release to the downstream reach, fish abundance and species richness were reduced by >47% and >35% respectively at downstream sites compared to unaffected upstream sites and >51% and >41% lower respectively compared to the pre-wastewater discharge period. The wastewater impact was particularly severe during months of low discharge (October–December). Water transparency, dissolved oxygen and pH were lower (P < 0.001) at impacted downstream sites compared to upstream sites. Nineteen species (41.3% of all species we recorded) are threatened in Bangladesh and the abundance of these species, except one, decreased significantly (P < 0.05) at the impacted sites. We recommend improved wastewater management by applying primary treatment facilities and incorporating reedbed filtration as a mean of biological treatment, into the canals carrying wastewaters. The success of such measures should be tested with fish species that were most responsive to wastewater, using the indicator species concept
Influencia de los métodos de conservación en las actividades enzimáticas de suelos forestales mediterráneos
Soil storage method may alter enzymatic activity being storage conditions of the soil samples prior to analysis decisive for the results. Studies made on freshly collected soils are generally preferred. However it is always not possible due to practical reasons since for example sampling is often restricted to short period of the year or because a great quantity of microbiological analyses must be made on time and by few people. On this context, soil storage methods are needed, being cold at 4°C the most widely used although sometimes alternative storage methods are also utilized. The aim of this study is to evaluate the effect of two alternative storage methods of soil samples (freezing at –20°C and air drying conservation methods) in comparison to cold at 4°C on the enzymatic activities (dehydrogenase, phosphatase, β-glucosidase and urease soil enzymes). Samples of two forest ecosystems (pine and holm oak forest stand) were taken in two different season of the year (winter and spring 2009). Results showed that enzymatic activities differed when freezing or air drying conservation methods were used in comparison with cold soil samples. Generally, alternative soil storage methods presented lower enzymatic activity than cold at 4°C. However, these changes depend on season and sampling location.El método de conservación del suelo utilizado puede alterar la actividad enzimática, siendo decisivas para los
resultados, las condiciones de conservación previas a los análisis. Para los estudios es preferible realizar los análisis
en muestras frescas y recién cogidas. Sin embargo, esto no es siempre posible por razones prácticas ya que las
muestras se tienen que recoger en un corto periodo del año o porque los análisis los debe hacer poca gente y siempre
en un determinado tiempo. En este contexto, se necesita un método de conservación, siendo el mantenimiento
en el frigorífico a 4°C el método más usado, aunque existen otros métodos alternativos. El objetivo de este trabajo
es el de evaluar el efecto de dos métodos alternativos de conservación (congelado a –20°C y secado a temperatura
ambiente) sobre las actividades enzimáticas (deshidrogenasa, fosfatasa, β-glucosidasa y ureasa), en comparación
con el mantenido en el frigorífico a 4°C. Las muestras se obtuvieron de dos zonas forestales diferentes (pinar
y encinar) y en dos épocas distintas (primavera y verano de 2009). Los resultados mostraron diferencias en las actividades
enzimáticas cuando se usó el congelado o secado al aire de las muestras de suelo en comparación con el
mantenimiento en el frigorífico. De forma general, los métodos de conservación alternativos mostraron una menor
actividad enzimática en las muestras de suelo analizadas. Sin embargo, estos cambios dependen de la época del año
y la zona de muestreo
TEMPORAL AND SPATIAL VARIABILITY OF ATMOSPHERIC PARTICLE NUMBER SIZE DISTRIBUTIONS ACROSS SPAIN
This study synthesizes for the first time results from simultaneous aerosol measurements performed at seven diverse locations distributed all over the Spanish geography. The observations were carried out during two field campaigns in 2012–2013, one-month each and during different seasons. These field campaigns were performed in the framework of the Spanish Network of DMAs (REDMAAS) activities. Measurement sites were grouped as polluted sites (urban background) and clean sites (rural background and high-altitude sites). Seasonal differences were more important at polluted sites, mainly related to meteorology and aerosol sources. Higher total particle concentrations were found during the cold period, driven mainly by Aitken-mode particles (traffic-related aerosol particles).This work has been financed by the Ministry of Science and Innovation (CGL2011-15008-E, CGL2010-1777, CGL2011-27020, CGL2014-52877-R, CGL2010-11095-E, CGL2012-39623-C02-01, CGL2014-55230-R & PI15/0051
20 years of the Atlantic Meridional Transect - AMT
The AMT (www.amt-uk.org) is a multidisciplinary programme which undertakes biological, chemical, and physical oceanographic research during an annual voyage between the UK and a destination in the South Atlantic such as the Falkland Islands, South Africa, or Chile. This transect of >12,000 km crosses a range of ecosystems from subpolar to tropical, from euphotic shelf seas and upwelling systems, to oligotrophic mid-ocean gyres. The year 2015 has seen two milestones in the history of the AMT: the achievement of 20 years of this unique ocean going programme and the departure of the 25th cruise on the 15th of September. Both of these events were celebrated in June this year with an open science conference hosted by the Plymouth Marine Laboratory (PML) and will be further documented in a special issue of Progress in Oceanography which is planned for publication in 2016. Since 1995, the 25 research cruises have involved 242 sea-going scientists from 66 institutes representing 22 countries. AMT was designed from the outset to be a collaborative programme. It was originally conceived by Jim Aiken, Patrick Holligan, Roger Harris, and Dave Robins with Chuck McClain and Chuck Trees at NASA to test and ground truth satellite algorithms of ocean color. The opportunities offered by this initiative meant that this series of repeated biannual cruises rapidly developed into a coordinated study of ocean biodiversity, biogeochemistry, and ocean/atmosphere interactions
Evidence for a mixed mass composition at the `ankle' in the cosmic-ray spectrum
We report a first measurement for ultra-high energy cosmic rays of the
correlation between the depth of shower maximum and the signal in the water
Cherenkov stations of air-showers registered simultaneously by the fluorescence
and the surface detectors of the Pierre Auger Observatory. Such a correlation
measurement is a unique feature of a hybrid air-shower observatory with
sensitivity to both the electromagnetic and muonic components. It allows an
accurate determination of the spread of primary masses in the cosmic-ray flux.
Up till now, constraints on the spread of primary masses have been dominated by
systematic uncertainties. The present correlation measurement is not affected
by systematics in the measurement of the depth of shower maximum or the signal
in the water Cherenkov stations. The analysis relies on general characteristics
of air showers and is thus robust also with respect to uncertainties in
hadronic event generators. The observed correlation in the energy range around
the `ankle' at differs significantly from
expectations for pure primary cosmic-ray compositions. A light composition made
up of proton and helium only is equally inconsistent with observations. The
data are explained well by a mixed composition including nuclei with mass . Scenarios such as the proton dip model, with almost pure compositions, are
thus disfavoured as the sole explanation of the ultrahigh-energy cosmic-ray
flux at Earth.Comment: Published version. Added journal reference and DOI. Added Report
Numbe
Measurement of the polarisation of W bosons produced with large transverse momentum in pp collisions at sqrt(s) = 7 TeV with the ATLAS experiment
This paper describes an analysis of the angular distribution of W->enu and
W->munu decays, using data from pp collisions at sqrt(s) = 7 TeV recorded with
the ATLAS detector at the LHC in 2010, corresponding to an integrated
luminosity of about 35 pb^-1. Using the decay lepton transverse momentum and
the missing transverse energy, the W decay angular distribution projected onto
the transverse plane is obtained and analysed in terms of helicity fractions
f0, fL and fR over two ranges of W transverse momentum (ptw): 35 < ptw < 50 GeV
and ptw > 50 GeV. Good agreement is found with theoretical predictions. For ptw
> 50 GeV, the values of f0 and fL-fR, averaged over charge and lepton flavour,
are measured to be : f0 = 0.127 +/- 0.030 +/- 0.108 and fL-fR = 0.252 +/- 0.017
+/- 0.030, where the first uncertainties are statistical, and the second
include all systematic effects.Comment: 19 pages plus author list (34 pages total), 9 figures, 11 tables,
revised author list, matches European Journal of Physics C versio
Observation of a new chi_b state in radiative transitions to Upsilon(1S) and Upsilon(2S) at ATLAS
The chi_b(nP) quarkonium states are produced in proton-proton collisions at
the Large Hadron Collider (LHC) at sqrt(s) = 7 TeV and recorded by the ATLAS
detector. Using a data sample corresponding to an integrated luminosity of 4.4
fb^-1, these states are reconstructed through their radiative decays to
Upsilon(1S,2S) with Upsilon->mu+mu-. In addition to the mass peaks
corresponding to the decay modes chi_b(1P,2P)->Upsilon(1S)gamma, a new
structure centered at a mass of 10.530+/-0.005 (stat.)+/-0.009 (syst.) GeV is
also observed, in both the Upsilon(1S)gamma and Upsilon(2S)gamma decay modes.
This is interpreted as the chi_b(3P) system.Comment: 5 pages plus author list (18 pages total), 2 figures, 1 table,
corrected author list, matches final version in Physical Review Letter
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