694 research outputs found
Involutions of polynomially parametrized surfaces
We provide an algorithm for detecting the involutions leaving a surface
defined by a polynomial parametrization invariant. As a consequence, the
symmetry axes, symmetry planes and symmetry center of the surface, if any, can
be determined directly from the parametrization, without computing or making
use of the implicit representation. The algorithm is based on the fact, proven
in the paper, that any involution of the surface comes from an involution of
the parameter space (the real plane, in our case); therefore, by determining
the latter, the former can be found. The algorithm has been implemented in the
computer algebra system Maple 17. Evidence of its efficiency for moderate
degrees, examples and a complexity analysis are also given
Ideal cardiovascular health predicts lower risk of abnormal liver enzymes levels in the Chilean National Health Survey (2009–2010)
High levels of gamma glutamyltransferase (gamma-GT) and alanine aminotransferase (ALT), as well as fatty liver index (FLI) has been associated with higher cardiovascular disease risk factors in adults. The aim of this study was to examine the relationship between gamma-GT, ALT, and fatty liver index FLI levels across a gradient number of ideal cardiovascular health metrics in a representative sample of adults from the Chilean National Health Survey 2009–2010. Data from 1,023 men and 1,449 women (≥ 15 years) from the Chilean Health Survey 2009–2010 were analyzed. Ideal cardiovascular health was defined as meeting ideal levels of the following components: four behaviours (smoking, body mass index, physical activity and diet adherence) and three factors (total cholesterol, blood pressure and fasting glucose). Adults were grouped into three categories according to their number of ideal cardiovascular health metrics: ideal (5–7 metrics), intermediate (3–4 metrics), and poor (0–2 metrics). Blood levels of gamma-GT and ALT were measured and the FLI was calculated. A higher number of ideal cardiovascular health index metric was associated with lower gamma-GT, ALT and FLI (p from trend analysis <0.001). Also, adults meeting at least 3–4 metrics were predicted less likely to have prevalence of abnormal levels of gamma-GT and FLI (p<0.001) compared to adults who met only 0–2 metrics. These findings reinforce the usefulness of the ideal cardiovascular health metrics proposed by the American Heart Association as a tool to identify target subjects and promote cardiovascular health in South-American adults
Ideal cardiovascular health predicts lower risk of abnormal liver enzymes levels in the Chilean National Health Survey (2009–2010)
High levels of gamma glutamyltransferase (gamma-GT) and alanine aminotransferase (ALT), as well as fatty liver index (FLI) has been associated with higher cardiovascular disease risk factors in adults. The aim of this study was to examine the relationship between gamma-GT, ALT, and fatty liver index FLI levels across a gradient number of ideal cardiovascular health metrics in a representative sample of adults from the Chilean National Health Survey 2009–2010. Data from 1,023 men and 1,449 women (≥ 15 years) from the Chilean Health Survey 2009–2010 were analyzed. Ideal cardiovascular health was defined as meeting ideal levels of the following components: four behaviours (smoking, body mass index, physical activity and diet adherence) and three factors (total cholesterol, blood pressure and fasting glucose). Adults were grouped into three categories according to their number of ideal cardiovascular health metrics: ideal (5–7 metrics), intermediate (3–4 metrics), and poor (0–2 metrics). Blood levels of gamma-GT and ALT were measured and the FLI was calculated. A higher number of ideal cardiovascular health index metric was associated with lower gamma-GT, ALT and FLI (p from trend analysis <0.001). Also, adults meeting at least 3–4 metrics were predicted less likely to have prevalence of abnormal levels of gamma-GT and FLI (p<0.001) compared to adults who met only 0–2 metrics. These findings reinforce the usefulness of the ideal cardiovascular health metrics proposed by the American Heart Association as a tool to identify target subjects and promote cardiovascular health in South-American adults
Effects of exercise training on Fetuin-a in obese, type 2 diabetes and cardiovascular disease in adults and elderly: A systematic review and Meta-analysis
Background: Elevated levels of fetuin-A are associated with increased risks of metabolic syndrome, type 2 diabetes and nonalcoholic fatty liver disease. This meta-analysis investigated whether exercise interventions can reduce fetuin-A in adults. Methods: We searched clinical trials that objectively assessed fetuin-A and included study arms with exercise intervention. The pre-intervention and post-intervention data were used for meta-analysis. The effect sizes were calculated as standardized mean differences or changes in fetuin-A and expressed as Hedges' g using random-effects models. Results: The overall Hedges' g for fetuin-A in all included interventions was - 0.640 (95%CI - 1.129 to - 0.151; n = 9), but this effect was not observed in obese (g = - 0.096; 95%CI, - 0.328 to 0.135) and type 2 diabetes/dysglycemia (g = - 0.56; 95%CI, - 1.348 to 0.236) individuals. Additionally, the random-effects meta-regression analysis showed that there was not a greater decrease in fetuin-A in individuals who achieved greater body mass index reductions (regression coefficient = 0.065; 95%CI, - 0.185 to 0.315). Conclusion: Supervised exercise is associated with reductions in fetuin-A levels in adults and elderly. However, the results of the present meta-analysis should be interpreted with caution because of the variety of type of exercises and individual obesity related-disorders involve. Therefore, additional high-quality randomized controlled trials describing the effect of supervised exercise interventions on fetuin-A in adults are still needed. © 2019 The Author(s)
A novel portable device to measure the temperature of both the inner and the outer tubes of a parabolic receiver in the field
The performance of parabolic trough (PT) receiver tubes (RT) has a direct impact on Solar Thermal Energy (STE) plant production. As a result, one major need of operation and maintenance (O&M) in STE plants is to monitor the state of the receiver tube as a key element in the solar field. However the lack of specific devices so far has limited the proper evaluation of operating receiver tubés thermal performance. As a consequence non-accurate approximations have been accepted until now using infrared thermal images of the glass outer tube. In order to fulfill this need, Abengoa has developed a unique portable device for evaluating the thermal performance and vacuum state of parabolic trough receiver tubes placed in the field. The novel device described in this paper, simultaneously provides the temperature of both the inner steel tube and the outer glass tube enabling a check on manufacturers specifications. The on-field evaluation of any receiver tube at any operating temperature has become possible thanks to this new measuring device. The features and usability of this new measurement system as a workable portable device in operating solar fields provide a very useful tool for all companies in the sector contributing to technology progress. The originality of the device, patent pending P201431969, is not limited to the CSP sector, also having scientific significance in the general measuring instruments field. This paper presents the work carried out to develop and validate the device, also detailing its functioning properties and including the excellent results obtained in the laboratory to determine its accuracy and standard deviation. This information was validated with data collected by O&M teams using this instrument in a commercial CSP plant. The relevance of the device has been evidenced by evaluating a wide sample of RT and the results are discussed in this paper. Finally, all the on field collected data is used to demonstrate the high impact that using this unique portable device will have on a parabolic trough solar power plant
A complement to the modern crystallographer's toolbox: Caged gadolinium complexes with versatile binding modes
A set of seven caged gadolinium complexes were used as vectors for introducing the chelated Gd3+ ion into protein crystals in order to provide strong anomalous scattering for de novo phasing. The complexes contained multidentate ligand molecules with different functional groups to provide a panel of possible interactions with the protein. An exhaustive crystallographic analysis showed them to be nondisruptive to the diffraction quality of the prepared derivative crystals, and as many as 50% of the derivatives allowed the determination of accurate phases, leading to high-quality experimental electron-density maps. At least two successful derivatives were identified for all tested proteins. Structure refinement showed that the complexes bind to the protein surface or solvent-accessible cavities, involving hydrogen bonds, electrostatic and CH-π interactions, explaining their versatile binding modes. Their high phasing power, complementary binding modes and ease of use make them highly suitable as a heavy-atom screen for high-throughput de novo structure determination, in combination with the SAD method. They can also provide a reliable tool for the development of new methods such as serial femtosecond crystallography. © 2014 International Union of Crystallography.Peer Reviewe
Perioperative management in thoracic surgery.
Thoracic surgery has undergone significant advances in recent years related to anesthetic and surgical techniques and the prevention and management of complications related to the procedure. This has allowed improvements in patient clinical outcomes in surgeries of this kind. Despite the above, thoracic surgery, especially related to pulmonary resection, is not without risk, and is associated to considerable morbidity and mortality. Fast track or enhanced recovery after anesthesia protocols, minimally invasive surgery, and intraoperative anesthetic management improve the prognosis and safety of thoracic surgery. Patients in the postoperative period of major thoracic surgery require intensive surveillance, especially the first 24–72h after surgery. Admission to the ICU is especially recommended in those patients with comorbidities, a reduced cardiopulmonary reserve, extensive lung resections, and those requiring support due to life-threatening organ failure. During the postoperative period, intensive cardiorespiratory monitoring, proper management of thoracic drainage, aggressive pain control (multimodal analgesia and regional anesthetic techniques), nausea and multimodal rehabilitation are key elements for avoiding adverse events. Medical complications include respiratory failure, arrhythmias, respiratory infections, atelectasis and thromboembolic lung disease. The most frequent surgical complications are hemothorax, chylothorax, bronchopleural fistula and prolonged air leakage. The multidisciplinary management of these patients throughout the perioperative period is essential in order to ensure the best surgical outcomes.post-print512 K
Exercise during pregnancy on maternal lipids: A secondary analysis of randomized controlled trial
Background: Today, scientific evidence has supported the popular belief that physical activity is associated with biological health in pregnant women. A randomized controlled trial was used to assess the benefits of physical exercise during pregnancy on maternal lipids in low-income Latina women. Methods: The study included 67 nulliparous low-income Latina women in gestational weeks 16-20, randomly assigned into one of two groups: 1) The exercise group, which took part in aerobic and resistance exercise for 60min, three times a week for 12weeks, 2) The control group, which undertook their usual physical activity and prenatal care. The primary outcomes were changes in maternal blood lipids after intervention. Obstetrical and neonatal outcomes measured were type of delivery, postpartum hemorrhage, newborn and/or maternal complications', gestational age, weight gain, birth weight, foetal growth, and Apgar score. Results: Fifty women completed the study. At the end of the intervention, there were differences between groups in low-density lipoprotein levels (mean change: -8mg/dL, 95%CI -3 to -29; P less than 0.001) and triglycerides (mean change: -6mg/dL, 95%CI -1 to -11; P=0.03). Also, compared with women who remained in the control group, active women showed lower complications during delivery (moderate postpartum haemorrhage) (58% compared with 75%; P less than 0.05) and lower complications in newborns (e.g. cyanosis or respiratory distress) (21% compared with 46%; P less than 0.001). Conclusions: An exercise programme during the second and third trimester favours less gain in low-density lipoprotein cholesterol and triglycerides fewer delivery and neonatal complications. Trial registration:NCT00741312(August 22, 2008). © 2017 The Author(s)
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