227 research outputs found
Strength, jumping, and change of direction speed asymmetries are not associated with athletic performance in elite academy soccer players
The aims of the present study were twofold: 1) to measure inter-limb asymmetries from a battery of fitness tests in youth soccer players and, 2) determine the association between asymmetry and measures of athletic performance. Sixteen elite youth soccer players (14.7 ± 0.2 years) performed a single leg Abalakov test (ABK), change of direction (COD) test over 10 m (5 + 5) and 20 m (10 + 10), and an iso-inertial power test. Subjects also performed 10 m, 20 m and 30 m sprints and a bilateral countermovement jump (CMJ), which were correlated with all ABK, COD and iso-inertial asymmetry scores. A one-way repeated measures ANOVA showed significant differences between inter-limb asymmetry scores across multiple tests (p 0.05) between the different inter-limb asymmetry scores, and between asymmetry scores and athletic performance. These findings show the test-specific nature of asymmetries in youth soccer players, with the iso-inertial power test being the most sensitive in detecting asymmetry. Moreover, the results obtained suggest that inherent asymmetry in young soccer players did not negatively impact their performance
Generation of induced pluripotent stem cells from human cord blood using OCT4 and SOX2
Mouse and human fibroblasts were the first cell types successfully reprog- rammed by ectopic expression of OCT4, SOX2, KLF4, and c-MYC (OSKM) (Lowry et al., 2008; Maherali et al., 2007; Park et al., 2008; Takahashi et al., 2007; Taka- hashi and Yamanaka, 2006; Yu et al., 2007). Further studies have shown that the age, origin, and cell type used have a deep impact on the reprogramming effi- ciency, eventually requiring the expres- sion of fewer factors and/or reducing the timing of the whole process. In general, stem cells are rare and difficult to access and isolate in large numbers (neural stem cells, for instance [Kim et al., 2008, 2009c]) and, therefore, represent a com- plicated target for reprogramming. How- ever, Cord Blood (CB) could represent an alternative and readily accessible source of stem cells. Here, we describe reprog- ramming of CB cells to pluripotency by retroviral transduction of four (OSKM), three (OSK), and as few as two (OS) tran- scription factors, without the need for additional chemical compounds
The 2HWC HAWC Observatory Gamma Ray Catalog
We present the first catalog of TeV gamma-ray sources realized with the
recently completed High Altitude Water Cherenkov Observatory (HAWC). It is the
most sensitive wide field-of-view TeV telescope currently in operation, with a
1-year survey sensitivity of ~5-10% of the flux of the Crab Nebula. With an
instantaneous field of view >1.5 sr and >90% duty cycle, it continuously
surveys and monitors the sky for gamma ray energies between hundreds GeV and
tens of TeV.
HAWC is located in Mexico at a latitude of 19 degree North and was completed
in March 2015. Here, we present the 2HWC catalog, which is the result of the
first source search realized with the complete HAWC detector. Realized with 507
days of data and represents the most sensitive TeV survey to date for such a
large fraction of the sky. A total of 39 sources were detected, with an
expected contamination of 0.5 due to background fluctuation. Out of these
sources, 16 are more than one degree away from any previously reported TeV
source. The source list, including the position measurement, spectrum
measurement, and uncertainties, is reported. Seven of the detected sources may
be associated with pulsar wind nebulae, two with supernova remnants, two with
blazars, and the remaining 23 have no firm identification yet.Comment: Submitted 2017/02/09 to the Astrophysical Journa
Daily monitoring of TeV gamma-ray emission from Mrk 421, Mrk 501, and the Crab Nebula with HAWC
We present results from daily monitoring of gamma rays in the energy range
to TeV with the first 17 months of data from the High
Altitude Water Cherenkov (HAWC) Observatory. Its wide field of view of 2
steradians and duty cycle of % are unique features compared to other TeV
observatories that allow us to observe every source that transits over HAWC for
up to hours each sidereal day. This regular sampling yields
unprecedented light curves from unbiased measurements that are independent of
seasons or weather conditions. For the Crab Nebula as a reference source we
find no variability in the TeV band. Our main focus is the study of the TeV
blazars Markarian (Mrk) 421 and Mrk 501. A spectral fit for Mrk 421 yields a
power law index and
an exponential cut-off
TeV. For Mrk 501, we find an index and exponential cut-off TeV. The light curves for both sources show clear
variability and a Bayesian analysis is applied to identify changes between flux
states. The highest per-transit fluxes observed from Mrk 421 exceed the Crab
Nebula flux by a factor of approximately five. For Mrk 501, several transits
show fluxes in excess of three times the Crab Nebula flux. In a comparison to
lower energy gamma-ray and X-ray monitoring data with comparable sampling we
cannot identify clear counterparts for the most significant flaring features
observed by HAWC.Comment: 18 pages, 10 figures, accepted for publication in The Astrophysical
Journa
Non-perturbative Euler-Heisenberg Lagrangian and Paraelectricity in Magnetized Massless QED
In this paper we calculate the non-perturbative Euler-Heisenberg Lagrangian
for massless QED in a strong magnetic field , where the breaking of the
chiral symmetry is dynamically catalyzed by the external magnetic field via the
formation of an electro-positron condensate. This chiral condensate leads to
the generation of dynamical parameters that have to be found as solutions of
non-perturbative Schwinger-Dyson equations. Since the electron-positron pairing
mechanism leading to the breaking of the chiral symmetry is mainly dominated by
the contributions from the infrared region of momenta much smaller than
, the magnetic field introduces a dynamical ultraviolet cutoff in
the theory that also enters in the non-perturbative Euler-Heisenberg action.
Using this action, we show that the system exhibits a significant
paraelectricity in the direction parallel to the magnetic field. The
nonperturbative nature of this effect is reflected in the non-analytic
dependence of the obtained electric susceptibility on the fine-structure
constant. The strong paraelectricity in the field direction is linked to the
orientation of the electric dipole moments of the pairs that form the chiral
condensate. The large electric susceptibility can be used to detect the
realization of the magnetic catalysis of chiral symmetry breaking in physical
systems.Comment: 18 pages, to be published in NP
Propagating Quantum Microwaves: Towards Applications in Communication and Sensing
The field of propagating quantum microwaves has started to receive
considerable attention in the past few years. Motivated at first by the lack of
an efficient microwave-to-optical platform that could solve the issue of secure
communication between remote superconducting chips, current efforts are
starting to reach other areas, from quantum communications to sensing. Here, we
attempt at giving a state-of-the-art view of the two, pointing at some of the
technical and theoretical challenges we need to address, and while providing
some novel ideas and directions for future research. Hence, the goal of this
paper is to provide a bigger picture, and -- we hope -- to inspire new ideas in
quantum communications and sensing: from open-air microwave quantum key
distribution to direct detection of dark matter, we expect that the recent
efforts and results in quantum microwaves will soon attract a wider audience,
not only in the academic community, but also in an industrial environment
Evaluation of 12 GWAS-drawn SNPs as biomarkers of rheumatoid arthritis response to TNF inhibitors. A potential SNP association with response to etanercept
Research in rheumatoid arthritis (RA) is increasingly focused on the discovery of biomarkers
that could enable personalized treatments. The genetic biomarkers associated with the
response to TNF inhibitors (TNFi) are among the most studied. They include 12 SNPs
exhibiting promising results in the three largest genome-wide association studies (GWAS).
However, they still require further validation. With this aim, we assessed their association
with response to TNFi in a replication study, and a meta-analysis summarizing all nonredundant
data. The replication involved 755 patients with RA that were treated for the first
time with a biologic drug, which was either infliximab (n = 397), etanercept (n = 155) or adalimumab
(n = 203). Their DNA samples were successfully genotyped with a single-base
extension multiplex method. Lamentably, none of the 12 SNPs was associated with
response to the TNFi in the replication study (p > 0.05). However, a drug-stratified exploratory
analysis revealed a significant association of the NUBPL rs2378945 SNP with a poor response to etanercept (B = -0.50, 95% CI = -0.82, -0.17, p = 0.003). In addition, the metaanalysis
reinforced the previous association of three SNPs: rs2378945, rs12142623, and
rs4651370. In contrast, five of the remaining SNPs were less associated than before, and
the other four SNPs were no longer associated with the response to treatment. In summary,
our results highlight the complexity of the pharmacogenetics of TNFi in RA showing that it
could involve a drug-specific component and clarifying the status of the 12 GWAS-drawn
SNPsThis work was supported by the Instituto
de Salud Carlos III (ISCIII, Spain) through grants
PI14/01651, PI17/01606 and RD16/0012/0014 to
AG and PI12/01909 to JJG-R. These grants are
partially financed by the European Regional
Development Fund of the EU (FEDER
Evaluation of 12 GWAS-drawn SNPs as biomarkers of rheumatoid arthritis response to TNF inhibitors. A potential SNP association with response to etanercept
Research in rheumatoid arthritis (RA) is increasingly focused on the discovery of biomarkers that could enable personalized treatments. The genetic biomarkers associated with the response to TNF inhibitors (TNFi) are among the most studied. They include 12 SNPs exhibiting promising results in the three largest genome-wide association studies (GWAS). However, they still require further validation. With this aim, we assessed their association with response to TNFi in a replication study, and a meta-analysis summarizing all non-redundant data. The replication involved 755 patients with RA that were treated for the first time with a biologic drug, which was either infliximab (n = 397), etanercept (n = 155) or adalimumab (n = 203). Their DNA samples were successfully genotyped with a single-base extension multiplex method. Lamentably, none of the 12 SNPs was associated with response to the TNFi in the replication study (p > 0.05). However, a drug-stratified exploratory analysis revealed a significant association of the NUBPL rs2378945 SNP with a poor response to etanercept (B = -0.50, 95% CI = -0.82, -0.17, p = 0.003). In addition, the meta-analysis reinforced the previous association of three SNPs: rs2378945, rs12142623, and rs4651370. In contrast, five of the remaining SNPs were less associated than before, and the other four SNPs were no longer associated with the response to treatment. In summary, our results highlight the complexity of the pharmacogenetics of TNFi in RA showing that it could involve a drug-specific component and clarifying the status of the 12 GWAS-drawn SNP
Validation Study Of Genetic Biomarkers Of Response To Tnf Inhibitors In Rheumatoid Arthritis
Genetic biomarkers are sought to personalize treatment of patients with rheumatoid arthritis (RA), given their variable response to TNF inhibitors (TNFi). However, no genetic biomaker is yet sufficiently validated. Here, we report a validation study of 18 previously reported genetic biomarkers, including 11 from GWAS of response to TNFi. The validation was attempted in 581 patients with RA that had not been treated with biologic antirheumatic drugs previously. Their response to TNFi was evaluated at 3, 6 and 12 months in two ways: change in the DAS28 measure of disease activity, and according to the EULAR criteria for response to antirheumatic drugs. Association of these parameters with the genotypes, obtained by PCR amplification followed by single-base extension, was tested with regression analysis. These analyses were adjusted for baseline DAS28, sex, and the specific TNFi. However, none of the proposed biomarkers was validated, as none showed association with response to TNFi in our study, even at the time of assessment and with the outcome that showed the most significant result in previous studies. These negative results are notable because this was the first independent validation study for 12 of the biomarkers, and because they indicate that prudence is needed in the interpretation of the proposed biomarkers of response to TNFi even when they are supported by very low p values. The results also emphasize the requirement of independent replication for validation, and the need to search protocols that could increase reproducibility of the biomarkers of response to TNFi
- …