University of Los Andes

About: University of Los Andes is a education organization based out in Bogotá, Colombia. It is known for research contribution in the topics: Population & Large Hadron Collider. The organization has 17616 authors who have published 25555 publications receiving 413463 citations.

Low muscle strength is associated with metabolic risk factors in Colombian children: the ACFIES study.

Abstract: Purpose In youth, poor cardiorespiratory and muscular strength are associated with elevated metabolic risk factors. However, studies examining associations between strength and risk factors have been done exclusively in high income countries, and largely in Caucasian cohorts. The aim of this study was to assess these interactions in schoolchildren in Colombia, a middle income Latin American country. Methods We measured body mass index, body composition, handgrip strength (HG), cardiorespiratory fitness (CRF) and metabolic risk factors in 669 low-middle socioeconomic status Colombian schoolchildren (mean age 11.52±1.13, 47% female). Associations between HG, CRF and metabolic risk factors were evaluated. Results HG and CRF were inversely associated with blood pressure, HOMA index and a composite metabolic risk score (p = 0.001), HOMA (β = −0.164; p = 0.005), triglycerides (β = −0.583; p = 0.026) and CRP (β = −0.183; p = 0.037) but not glucose (p = 0.698) or HDL cholesterol (p = 0.132). The odds ratios for having clustered risk in the weakest quartile compared with the strongest quartile were 3.0 (95% confidence interval: 1.81–4.95). Conclusions In Colombian schoolchildren both poorer handgrip strength/kg body mass and cardiorespiratory fitness were associated with a worse metabolic risk profile. Associations were stronger and more consistent between handgrip and risk factors than between cardiorespiratory fitness and these risk factors. Our findings indicate the addition of handgrip dynamometry to non-invasive youth health surveillance programs would improve the accuracy of the assessment of cardio-metabolic health.

Time Dependence of the Ultraviolet Radiation Field in the Local Interstellar Medium

Abstract: Far Ultraviolet (FUV, 6 eV< h� <13.6 eV) radiation has been recognized as the main source of heating of the neutral interstellar gas, and, as a consequence, it determines whether the thermal balance of the neutral gas results in cold (T � 50 − 100K) clouds (CNM), warm (T � 10 4 K) clouds (WNM), or a combination of the two. High FUV fields convert the neutral gas to WNM, while low fields result in CNM. The knowledge of how these fractions depend on the FUV sources (i.e. the star formation rate, the IMF, and the size distribution of associations) is a basic step in building any detailed model of the large scale behavior of the ISM and the mutual relation between the ISM and the star formation rate in a galaxy. The sources of FUV radiation are the short-lived massive stars that generally originate in associations that form in Giant Molecular Clouds present in the galactic disk. Using McKee & Williams’ (1997) distribution of birthrates for OB associations in the Galaxy, we determine the expected behavior of the time-dependent FUV field for random positions in the local ISM. The FUV field is calculated in two bands (912 − 1100 u and 912 − 2070 u and at the wavelength 1400 u In terms of U−17 � U=(10 −17 erg cm −3 u −1 ), where U is the energy density of the radiation field in some band, we find (mean, median) values at the solar circle of U−17 =(15.7, 7.4) and (14.2, 7.2) for the [912-1100 u and [912-2070 u bands, respectively. At 1400 u we find (mean, median) values of U−17 =(14.4, 7.5). Our median value for the [912-2070 u band is G0 = 1:6 times Habing’s (1968) value for the radiation field at the solar circle in this band, and quite close to Draine’s (1976) value, G0 = 1:7. Both the latter values are based on observations of sources of FUV radiation in the solar neighborhood, so all three values are close to observed values. Due to attenuation by dust, only associations within about 500 pc contribute significantly to the energy density at a given point. Large angle scattering produces a diffuse field that is about 10% of the field produced by the sum of direct and small angle (< 5 o ) scattering from discrete sources (the associations), as observed. At a point exposed to the median radiation field, the brightest association typically produces about 20% of the total energy density. At a

Observation of the associated production of a single top quark and a $W$ boson in $pp$ collisions at $\sqrt s = $8 TeV

Abstract: The first observation of the associated production of a single top quark and a W boson is presented. The analysis is based on a data set corresponding to an integrated luminosity of 12.2 fb^(−1) of proton-proton collisions at √s=8 TeV recorded by the CMS experiment at the LHC. Events with two leptons and a jet originating from a b quark are selected. A multivariate analysis based on kinematic and topological properties is used to separate the signal from the dominant tt background. An excess consistent with the signal hypothesis is observed, with a significance which corresponds to 6.1 standard deviations above a background-only hypothesis. The measured production cross section is 23.4±5.4 pb , in agreement with the standard model prediction.

Advantages of submuscular bridge plating for complex pediatric femur fractures.

Abstract: Conventional treatments of pediatric femoral shaft fractures may result in an unacceptable rate of complications, especially in complex fractures. These fractures include high-energy injuries resulting in unstable fracture patterns, fractures in the proximal or distal third, and fractures occurring in large or multiply injured children. Our goal was to evaluate whether a minimally invasive submuscular bridge plating technique provides stability for early functional treatment (without protective casting or bracing) and predictable healing. Fifty-one patients with an average age of 10 years were studied. Sixty-seven percent had high-energy injuries and 55% had unstable fracture patterns. With an average followup of 14.2 months, all fractures united with excellent clinical results. Two (4%) significant complications occurred: fracture of one 3.5-mm LC-DCP Ti plate, and refracture of a pathologic fracture after early plate removal. Four patients (8%) had a leg-length discrepancy ranging from 23-mm short to 10-mm long. The average operative time was 106 minutes, with average fluoroscopy time of 84 seconds. Procedures were done by 15 surgeons in five university medical centers. This technique offers the advantage of adequate stability for early functional treatment and predictable healing with maintenance of length and alignment for all pediatric femoral shaft fractures.