1,280 research outputs found
Finding Best Compiler Options for Critical Software Using Parallel Algorithms
The efficiency of a software piece is a key factor for many systems. Real-time programs, critical software, device drivers, kernel OS functions and many other software pieces which are executed thousands or even millions of times per day require a very efficient execution. How this software is built can significantly affect the run time for these programs, since the context is that of compile-once/run-many. In this sense, the optimization flags used during the compilation time are a crucial element for this goal and they could make a big difference in the final execution time. In this paper, we use parallel metaheuristic techniques to automatically decide which optimization flags should be activated during the compilation on a set of benchmarking programs. The using the appropriate flag configuration is a complex combinatorial problem, but our approach is able to adapt the flag tuning to the characteristics of the software, improving the final run times with respect to other spread practicesThis research has been partially funded by the Spanish MINECO and FEDER projects (TIN2014-57341-R (http://moveon.lcc.uma.es), TIN2016-81766-REDT (http://cirti.es), and TIN2017-88213-R (http://6city.lcc.uma.es). It is also funded by Universidad de MĂĄlaga. Campus de Excelencia Internacional AndalucĂa Tech
Remote ischemic preconditioning in patients with intermittent claudication
OBJECTIVE: Remote ischemic preconditioning (RIPC) is a phenomenon in which a short period of sub-lethal ischemia in one organ protects against subsequent bouts of ischemia in another organ. We hypothesized that RIPC in patients with intermittent claudication would increase muscle tissue resistance to ischemia, thereby resulting in an increased ability to walk.
METHODS: In a claudication clinic, 52 ambulatory patients who presented with complaints of intermittent claudication in the lower limbs associated with an absent or reduced arterial pulse in the symptomatic limb and/or an ankle-brachial index <0.90 were recruited for this study. The patients were randomly divided into three groups (A, B and C). All of the patients underwent two tests on a treadmill according to the Gardener protocol. Group A was tested first without RIPC. Group A was subjected to RIPC prior to the second treadmill test. Group B was subjected to RIPC prior to the first treadmill test and then was subjected to a treadmill test without RIPC. In Group C (control group), both treadmill tests were performed without RIPC. The first and second tests were conducted seven days apart. Brazilian Clinical Trials: RBR-7TF6TM.
RESULTS: Group A showed a significant increase in the initial claudication distance in the second test compared to the first test.
CONCLUSION: RIPC increased the initial claudication distance in patients with intermittent claudication; however, RIPC did not affect the total walking distance of the patients
Peak expiratory flow mediates the relationship between handgrip strength and timed up and go performance in elderly women, but not men
OBJECTIVE: The aim of the present study was to verify if there is sex difference in the associations among handgrip strength, peak expiratory flow (PEF) and timed up and go (TUG) test results.
METHODS: The sample included 288 consecutive elderly men (n=93) and women (n=195). Functional capacity was measured using the TUG test, and muscle strength was measured based on handgrip. Moreover, as a measure of current health status, PEF was evaluated. Linear regression procedures were performed to analyze the relationships between handgrip and both PEF and TUG test results, with adjustment for confounders, and to identify the possible mediating role of PEF in the association between handgrip strength and TUG test results.
RESULTS: In men, handgrip strength was associated with both PEF and TUG performance (p<0.01). After adjustment for PEF, the relationship between handgrip strength and TUG performance remained significant. In women, handgrip strength was also associated with both PEF and TUG performance (p<0.01). However, after adjustment for PEF, the relationship between handgrip strength and TUG performance was no longer significant.
CONCLUSION: Mobility in the elderly is sex dependent. In particular, PEF mediates the relationship between handgrip strength and TUG performance in women, but not in men
Predictors of walking capacity in peripheral arterial disease patients
OBJECTIVE: To estimate walking capacity in intermittent claudication patients through a prediction model based on clinical characteristics and the walking impairment questionnaire.
METHODS: The sample included 133 intermittent claudication patients of both genders aged between 30 and 80 years. Data regarding clinical characteristics, the walking impairment questionnaire and treadmill walking test performance were obtained. Multiple regression modeling was conducted to predict claudication onset distance and total walking distance using clinical characteristics (age, height, mass, body mass index, ankle brachial index lower, gender, history of smoking and co-morbid conditions) and walking impairment questionnaire responses. Comparisons of claudication onset distance and total walking distance measured during treadmill tests and estimated by a regression equation were performed using paired t-tests.
RESULTS: Co-morbid conditions (diabetes and coronary artery disease) and questions related to difficulty in walking short distances (walking indoors - such as around your house and walking 5 blocks) and at low speed (walking 1 block at average speed - usual pace) resulted in the development of new prediction models high significant for claudication onset distance and total walking distance (p0.05) were observed.
CONCLUSION: The current study demonstrated that walking capacity can be adequately estimated based on co-morbid conditions and responses to the walking impairment questionnaire
Evaluando tecnologĂas electorales nuevas en AmĂ©rica Latina
publication-status: Publishe
Learning Interpretable Rules for Multi-label Classification
Multi-label classification (MLC) is a supervised learning problem in which,
contrary to standard multiclass classification, an instance can be associated
with several class labels simultaneously. In this chapter, we advocate a
rule-based approach to multi-label classification. Rule learning algorithms are
often employed when one is not only interested in accurate predictions, but
also requires an interpretable theory that can be understood, analyzed, and
qualitatively evaluated by domain experts. Ideally, by revealing patterns and
regularities contained in the data, a rule-based theory yields new insights in
the application domain. Recently, several authors have started to investigate
how rule-based models can be used for modeling multi-label data. Discussing
this task in detail, we highlight some of the problems that make rule learning
considerably more challenging for MLC than for conventional classification.
While mainly focusing on our own previous work, we also provide a short
overview of related work in this area.Comment: Preprint version. To appear in: Explainable and Interpretable Models
in Computer Vision and Machine Learning. The Springer Series on Challenges in
Machine Learning. Springer (2018). See
http://www.ke.tu-darmstadt.de/bibtex/publications/show/3077 for further
informatio
Teprotumumab for Thyroid-Associated Ophthalmopathy
BACKGROUND: Thyroid-associated ophthalmopathy, a condition commonly associated with Gravesâ disease, remains inadequately treated. Current medical therapies, which primarily consist of glucocorticoids, have limited efficacy and present safety concerns. Inhibition of the insulin-like growth factor I receptor (IGF-IR) is a new therapeutic strategy to attenuate the underlying autoimmune pathogenesis of ophthalmopathy. / METHODS: We conducted a multicenter, double-masked, randomized, placebo-controlled trial to determine the efficacy and safety of teprotumumab, a human monoclonal antibody inhibitor of IGF-IR, in patients with active, moderate-to-severe ophthalmopathy. A total of 88 patients were randomly assigned to receive placebo or active drug administered intravenously once every 3 weeks for a total of eight infusions. The primary end point was the response in the study eye. This response was defined as a reduction of 2 points or more in the Clinical Activity Score (scores range from 0 to 7, with a score of â„3 indicating active thyroid-associated ophthalmopathy) and a reduction of 2 mm or more in proptosis at week 24. Secondary end points, measured as continuous variables, included proptosis, the Clinical Activity Score, and results on the Gravesâ ophthalmopathyâspecific quality-of-life questionnaire. Adverse events were assessed. / RESULTS: In the intention-to-treat population, 29 of 42 patients who received teprotumumab (69%), as compared with 9 of 45 patients who received placebo (20%), had a response at week 24 (P<0.001). Therapeutic effects were rapid; at week 6, a total of 18 of 42 patients in the teprotumumab group (43%) and 2 of 45 patients in the placebo group (4%) had a response (P<0.001). Differences between the groups increased at subsequent time points. The only drug-related adverse event was hyperglycemia in patients with diabetes; this event was controlled by adjusting medication for diabetes. / CONCLUSIONS: In patients with active ophthalmopathy, teprotumumab was more effective than placebo in reducing proptosis and the Clinical Activity Score. (Funded by River Vision Development and others; ClinicalTrials.gov number, NCT01868997.
Mitochondrial haplogroup H1 is protective for ischemic stroke in Portuguese patient
BACKGROUND:
The genetic contribution to stroke is well established but it has proven difficult to identify the genes and the disease-associated alleles mediating this effect, possibly because only nuclear genes have been intensely investigated so far. Mitochondrial DNA (mtDNA) has been implicated in several disorders having stroke as one of its clinical manifestations. The aim of this case-control study was to assess the contribution of mtDNA polymorphisms and haplogroups to ischemic stroke risk.
METHODS:
We genotyped 19 mtDNA single nucleotide polymorphisms (SNPs) defining the major European haplogroups in 534 ischemic stroke patients and 499 controls collected in Portugal, and tested their allelic and haplogroup association with ischemic stroke risk.
RESULTS:
Haplogroup H1 was found to be significantly less frequent in stroke patients than in controls (OR = 0.61, 95% CI = 0.45-0.83, p = 0.001), when comparing each clade against all other haplogroups pooled together. Conversely, the pre-HV/HV and U mtDNA lineages emerge as potential genetic factors conferring risk for stroke (OR = 3.14, 95% CI = 1.41-7.01, p = 0.003, and OR = 2.87, 95% CI = 1.13-7.28, p = 0.021, respectively). SNPs m.3010G>A, m.7028C>T and m.11719G>A strongly influence ischemic stroke risk, their allelic state in haplogroup H1 corroborating its protective effect.
CONCLUSION:
Our data suggests that mitochondrial haplogroup H1 has an impact on ischemic stroke risk in a Portuguese sample
Localization of gravity on a de Sitter thick braneworld without scalar fields
In this work we present a simple thick braneworld model that is generated by
an intriguing interplay between a 5D cosmological constant with a de Sitter
metric induced in the 3-brane without the inclusion of scalar fields. We show
that 4D gravity is localized on this brane, provide analytic expressions for
the massive Kaluza-Klein (KK) fluctuation modes and also show that the spectrum
of metric excitations displays a mass gap. We finally present the corrections
to Newton's law due to these massive modes. This model has no naked
singularities along the fifth dimension despite the existence of a mass gap in
the graviton spectrum as it happens in thick branes with 4D Poincare symmetry,
providing a simple model with very good features: the curvature is completely
smooth along the fifth dimension, it localizes 4D gravity and the spectrum of
gravity fluctuations presents a mass gap, a fact that rules out the existence
of phenomenologically dangerous ultralight KK excitations in the model. We
finally present our solution as a limit of scalar thick branes.Comment: 11 pages in latex, no figures, title and abstract changed, a new
section and some references adde
Velocity vector imaging to quantify left atrial function
The aim of our study was to assess the feasibility of a new image analysis, velocity vector imaging (VVI), in the assessment of left atrial volumes (LAV) and left atrial ejection fraction (LAEF). We retrospectively analysed 100 transthoracic echocardiographic findings in 71 men, and 29 women (mean age 57 ± 19.8 years). Two subgroups of patients were defined: (1) with left ventricular (LV) EF > 50%, and (2) LV EF < 50%. For the VVI method of indexed LAV assessment we used the apical four-chamber view. From the displacement of LA endocardial pixels timeâvolume curves were extracted which provided automatically data regarding indexed maximum LAV (LAVImax), indexed minimum LAV (LAVImin), and LAEF. LAVs and LAEF by 2-dimensional echocardiograhy (2DE) were measured by Simpsonâs biplane disc summation method. Comparing LAVImax, LAVImin, and LAEF by VVI versus 2DE in the total study population, we found significant correlations: r = 0.94, P < 0.0001, r = 0.94, P < 0.0001, r = 0.79, P < 0.0001, respectively. In addition, LAVImax â„ 40 ml/m2 was 94% sensitive and 72% specific, LAVImin â„ 27 ml/m2 was 90% sensitive and 86% specific, and LAEF < 30% was 80% sensitive and 96% specific for the detection of LV systolic dysfunction. There were highly significant inverse associations of LAVImax and LAVImin to LVEF. LAEF was also significantly related to LV systolic function. When comparing the time required for VVI and 2DE measurements, VVI led to 62% reduction in the measurement time. In conclusion, VVI is a feasible method for the assessment of LAVs and LAEF. It provides close agreement with that measured by conventional 2DE Simpsonâs biplane method with significant time saved
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