3,679 research outputs found
Moduli spaces for finite-order jets of Riemannian metrics
We construct the moduli space of r-jets at a point of Riemannian metrics on a
smooth manifold. The construction is closely related to the problem of
classification of jet metrics via differential invariants. The moduli space is
proved to be a differentiable space which admits a finite canonical
stratification into smooth manifolds. A complete study on the stratification of
moduli spaces is carried out for metrics in dimension n=2.Comment: 25 pages, corrected typos, partially changed content with an appendix
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Acute Effects of ACL Injury-Prevention Warm-Up and Soccer-Specific Fatigue Protocol on Dynamic Knee Valgus in Youth Male Soccer Players
Childhood anterior cruciate ligament (ACL) injuries—which can pose a major risk to a child’s sporting career—have been on the rise in the last few decades. Dynamic knee valgus (DKV) has been linked to an increased risk of ACL injury. Therefore, the aim of this study was to analyze the acute effects of an ACL injury prevention protocol (ACL-IPP) and a soccer-specific fatigue protocol (SSFP) on DKV in youth male soccer players. The research hypothesis was that DKV would be reduced by the ACL-IPP and increased by the SSFP. Eighteen youth male soccer players were divided according to baseline DKV. Those with moderate or large DKV performed a neuromuscular training protocol based on activation of the abductor and external rotator hip muscles. Those with little or no DKV performed a soccer-specific fatigue protocol. DKV was assessed using the single-leg squat pre- and post-protocols in both legs. The ACL-IPP significantly decreased DKV during single-leg squat (p < 0.01, effect size = 1.39), while the SSFP significantly increased baseline DKV in the dominant leg during single-leg squat (p = 0.012; effect size = 1.74). In conclusion, the ACL-IPP appears to acutely reduce the DKV in youth male soccer players, and the SSFP seems to acutely increase the DKV in those players who showed a light or no DKV in a non-fatigue situation. By using the SSFP, it may be possible to determine which players would benefit from injury prevention programs due to increased DKV during game scenarios, while hip abductor and external rotator neuromuscular training may be beneficial for players who have moderate and severe DKV during single-leg squat under non-fatigued scenarios
Occupant-Centred Control strategies for Adaptive Facades: A preliminary study of the impact of shortwave solar radiation on thermal comfort
Adaptive facades have the potential to shape resource-efficient and occupant-centred spaces only when their control strategies are tailored to meet transient, local and personal demands. State-of-the-art control algorithms are currently failing to provide occupant thermal satisfaction because the data on occupant response to the thermal environment is not sufficiently granular. This paper presents a preliminary assessment of the use of the adjusted operative temperature, which accounts also for the additional effect of shortwave radiation on occupants, to dynamically devise learning control strategies that meet individual occupant comfort requirements. Shortwave effects of solar radiation on occupant comfort and operative temperature are compared to those considering only longwave radiation and two alternative occupant-centred control strategies are devised and assessed. Lastly, a combined occupant-centred control strategy is also proposed for an open space office
Gelatin–chitosan–PVA hydrogels and their application in agriculture
This work demonstrated the ability of a fabrication process in the preparation of gelatin-chitosan-PVA hydrogels
for potential agricultural applications. The hydrogels showed a dense, tridimensional, interconnected and reticulated structure
that was more evident in the hydrogel loaded with inulin. The hydrogels showed a water absorption capacity of ≤12 times
its mass. FTIR and light microscopy demonstrated that the hydrogels were biodegradable. The percentage of degradation
of hydrogels in inoculated soil was higher than in sterile soil using the soil burial test. Hydrogel loaded with inulin was found
to be capable of inducing resistance in chili plants against Phytophthora capsici.ITESO, A.C
No Place Like Home: Examining a Bilingual-Bicultural, Self-Run Substance Abuse Recovery Home for Latinos
Latinos often do not seek substance abuse services, and this might be correlated to the lack of culturally-modified substance abuse treatment approaches. Oxford House is the largest self-help residential recovery program in the U.S., yet few Latinos are among their current residents. In an effort to change this, bilingual-bicultural recovery homes were recently developed for Latinos. This article describes the process in opening these bilingual-bicultural houses and how sociocultural factors such as the family, simpatĂa, and gender roles impacted the living environment of these houses. In addition, language is highlighted as a key factor to the comfort and success of Latinos living in Oxford Houses. Based on these experiences, the article addresses several obstacles/barriers that impacted this process and possible feasible solutions to these challenges. One challenge is the Latino family system. While this may provide a supportive, cost-effective option for some; it can also perpetuate a cycle of codependence and substance abuse
Evidence for dark matter in the inner Milky Way
The ubiquitous presence of dark matter in the universe is today a central
tenet in modern cosmology and astrophysics. Ranging from the smallest galaxies
to the observable universe, the evidence for dark matter is compelling in
dwarfs, spiral galaxies, galaxy clusters as well as at cosmological scales.
However, it has been historically difficult to pin down the dark matter
contribution to the total mass density in the Milky Way, particularly in the
innermost regions of the Galaxy and in the solar neighbourhood. Here we present
an up-to-date compilation of Milky Way rotation curve measurements, and compare
it with state-of-the-art baryonic mass distribution models. We show that
current data strongly disfavour baryons as the sole contribution to the
galactic mass budget, even inside the solar circle. Our findings demonstrate
the existence of dark matter in the inner Galaxy while making no assumptions on
its distribution. We anticipate that this result will compel new
model-independent constraints on the dark matter local density and profile,
thus reducing uncertainties on direct and indirect dark matter searches, and
will shed new light on the structure and evolution of the Galaxy.Comment: First submitted version of letter published in Nature Physics on
Febuary 9, 2015:
http://www.nature.com/nphys/journal/vaop/ncurrent/full/nphys3237.htm
Brain Sci
Mild cognitive impairment (MCI) (amnestic or non-amnestic) has different clinical and neuropsychological characteristics, and its evolution is heterogeneous. Cardiovascular risk factors (CVRF), such as hypertension, diabetes, or dyslipidemia, and the presence of the Apolipoprotein E epsilon4 (ApoE epsilon4) polymorphism have been associated with an increased risk of developing Alzheimer's disease (AD) and other dementias but the relationship is inconsistent worldwide. We aimed to establish the association between the ApoE epsilon4 carrier status and CVRF on MCI subtypes (amnestic and non-amnestic) in Mexican older adults. Cross-sectional study including 137 older adults (n = 63 with normal cognition (NC), n = 24 with amnesic, and n = 50 with non-amnesic MCI). Multinomial logistic regression models were performed in order to determine the association between ApoE epsilon4 polymorphism carrier and CVRF on amnestic and non-amnestic-MCI. ApoE epsilon4 carrier status was present in 28.8% participants. The models showed that ApoE epsilon4 carrier status was not associated neither aMCI nor naMCI condition. The interaction term ApoE epsilon4 x CVRF was not statistically significant for both types of MCI. However, CVRF were associated with both types of MCI and the association remained statistically significant after adjustment by sex, age, and education level. The carrier status of the ApoE genotype does not contribute to this risk
Hypertriglyceridemia Influences the Degree of Postprandial Lipemic Response in Patients with Metabolic Syndrome and Coronary Artery Disease: From the Cordioprev Study
Objective
To determine whether metabolic syndrome traits influence the postprandial lipemia response of coronary patients, and whether this influence depends on the number of MetS criteria.
Materials and Methods
1002 coronary artery disease patients from the CORDIOPREV study were submitted to an oral fat load test meal with 0.7 g fat/kg body weight (12% saturated fatty acids, 10% polyunsaturated fatty acids, 43% monounsaturated fatty acids), 10% protein and 25% carbohydrates. Serial blood test analyzing lipid fractions were drawn at 0, 1, 2, 3 and 4 hours during the postprandial state. Total and incremental area under the curves of the different postprandial parameters were calculated following the trapezoid rule to assess the magnitude of change during the postprandial state
Results
Postprandial lipemia response was directly related to the presence of metabolic syndrome. We found a positive association between the number of metabolic syndrome criteria and the response of postprandial plasma triglycerides (p<0.001), area under the curve of triglycerides (p<0.001) and incremental area under the curve of triglycerides (p<0.001). However, the influence of them on postprandial triglycerides remained statistically significant only in those patients without basal hypertriglyceridemia. Interestingly, in stepwise multiple linear regression analysis with the AUC of triglycerides as the dependent variable, only fasting triglycerides, fasting glucose and waist circumference appeared as significant independent (P<0.05) contributors. The multiple lineal regression (R) was 0.77, and fasting triglycerides showed the greatest effect on AUC of triglycerides with a standardized coefficient of 0.75.
Conclusions
Fasting triglycerides are the major contributors to the postprandial triglycerides levels. MetS influences the postprandial response of lipids in patients with coronary heart disease, particularly in non-hypertriglyceridemic patients
ICTV virus taxonomy profile: Ophioviridae
The Ophioviridae is a family of filamentous plant viruses, with single-stranded negative, and possibly ambisense, RNA genomes of 11.3-12.5 kb divided into 3-4 segments, each encapsidated separately. Virions are naked filamentous nucleocapsids, forming kinked circles of at least two different contour lengths. The sole genus, Ophiovirus, includes seven species. Four ophioviruses are soil-transmitted and their natural hosts include trees, shrubs, vegetables and bulbous or corm-forming ornamentals, both monocots and dicots. This is a summary of the International Committee on Taxonomy of Viruses (ICTV) Report on the taxonomy of the Ophioviridae, which is available at http://www.ictv.global/report/ophioviridae.Instituto de Biotecnologia y Biologia MolecularFacultad de Ciencias Agrarias y Forestale
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