988 resultados para Large friction


Relevância:

20.00% 20.00%

Publicador:

Resumo:

Human cooperation is typically coordinated by institutions, which determine the outcome structure of the social interactions individuals engage in. Explaining the Neolithic transition from small- to large-scale societies involves understanding how these institutions co-evolve with demography. We study this using a demographically explicit model of institution formation in a patch-structured population. Each patch supports both social and asocial niches. Social individuals create an institution, at a cost to themselves, by negotiating how much of the costly public good provided by cooperators is invested into sanctioning defectors. The remainder of their public good is invested in technology that increases carrying capacity, such as irrigation systems. We show that social individuals can invade a population of asocials, and form institutions that support high levels of cooperation. We then demonstrate conditions where the co-evolution of cooperation, institutions, and demographic carrying capacity creates a transition from small- to large-scale social groups.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This project involved the evaluation of several aggregates previously rated poor to excellent with respect to skid resistance and certain mix design parameters. An open graded asphalt friction course was evaluated using 4 comparably graded aggregates: quartzite, fine grained limestone, coarse limestone and lightweight expanded shale. The performance investigations involved the verification of observations of the quartzite test sections, evaluation of the effect of blending the superior quartzite with a typical coarse grained-textured limestone, and the evaluation of the limestone. The effects of traffic on the aggregates used in the test sections were studied, as well as the relationship between asphalt content levels and traffic with respect to performance. The bond of the open graded friction course mixture was also evaluated. The SN performance of all test sections after sixteen months of exposure was found to be satisfactory in that none of the material combinations had polished to the point where unacceptable SN levels developed. When material combinations were compared, significant differences were noted.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Background The superiority of a chemotherapy with doxorubicin, cyclophosphamide, vindesine, bleomycin and prednisone (ACVBP) in comparison with cyclophosphamide, doxorubicin, vincristin and prednisone plus radiotherapy for young patients with localized diffuse large B-cell lymphoma (DLBCL) was previously demonstrated. We report the results of a trial which evaluates the role of rituximab combined with ACVBP (R-ACVBP) in these patients. Patients and methods Untreated patients younger than 66 years with stage I or II DLBCL and no adverse prognostic factors of the age-adjusted International Prognostic Index were randomly assigned to receive three cycles of ACVBP plus sequential consolidation with or without the addition of four infusions of rituximab. Results A total of 223 patients were randomly allocated to the study, 110 in the R-ACVBP group and 113 in the ACVBP group. After a median follow-up of 43 months, our 3-year estimate of event-free survival was 93% in the R-ACVBP group and 82% in the ACVBP group (P = 0.0487). Three-year estimate of progression-free survival was increased in the R-ACVBP group (95% versus 83%, P = 0.0205). Overall survival did not differ between the two groups with a 3-year estimates of 98% and 97%, respectively (P = 0.686). Conclusion In young patients with low-risk localized DLBCL, rituximab combined with three cycles of ACVBP plus consolidation is significantly superior to ACVBP plus consolidation alone.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

We present a new framework for large-scale data clustering. The main idea is to modify functional dimensionality reduction techniques to directly optimize over discrete labels using stochastic gradient descent. Compared to methods like spectral clustering our approach solves a single optimization problem, rather than an ad-hoc two-stage optimization approach, does not require a matrix inversion, can easily encode prior knowledge in the set of implementable functions, and does not have an ?out-of-sample? problem. Experimental results on both artificial and real-world datasets show the usefulness of our approach.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Bionformatics is a rapidly evolving research field dedicated toanalyzing and managing biological data with computational resources. This paperaims to overview some of the processes and applications currently implementedat CCiT-UB¿s Bioinformatics Unit, focusing mainly on the areas of Genomics,Transcriptomics and Proteomics

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The success of combination antiretroviral therapy is limited by the evolutionary escape dynamics of HIV-1. We used Isotonic Conjunctive Bayesian Networks (I-CBNs), a class of probabilistic graphical models, to describe this process. We employed partial order constraints among viral resistance mutations, which give rise to a limited set of mutational pathways, and we modeled phenotypic drug resistance as monotonically increasing along any escape pathway. Using this model, the individualized genetic barrier (IGB) to each drug is derived as the probability of the virus not acquiring additional mutations that confer resistance. Drug-specific IGBs were combined to obtain the IGB to an entire regimen, which quantifies the virus' genetic potential for developing drug resistance under combination therapy. The IGB was tested as a predictor of therapeutic outcome using between 2,185 and 2,631 treatment change episodes of subtype B infected patients from the Swiss HIV Cohort Study Database, a large observational cohort. Using logistic regression, significant univariate predictors included most of the 18 drugs and single-drug IGBs, the IGB to the entire regimen, the expert rules-based genotypic susceptibility score (GSS), several individual mutations, and the peak viral load before treatment change. In the multivariate analysis, the only genotype-derived variables that remained significantly associated with virological success were GSS and, with 10-fold stronger association, IGB to regimen. When predicting suppression of viral load below 400 cps/ml, IGB outperformed GSS and also improved GSS-containing predictors significantly, but the difference was not significant for suppression below 50 cps/ml. Thus, the IGB to regimen is a novel data-derived predictor of treatment outcome that has potential to improve the interpretation of genotypic drug resistance tests.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

In order to distinguish dysfunctional gait; clinicians require a measure of reference gait parameters for each population. This study provided normative values for widely used parameters in more than 1400 able-bodied adults over the age of 65. We also measured the foot clearance parameters (i.e., height of the foot above ground during swing phase) that are crucial to understand the complex relationship between gait and falls as well as obstacle negotiation strategies. We used a shoe-worn inertial sensor on each foot and previously validated algorithms to extract the gait parameters during 20 m walking trials in a corridor at a self-selected pace. We investigated the difference of the gait parameters between male and female participants by considering the effect of age and height factors. Besides; we examined the inter-relation of the clearance parameters with the gait speed. The sample size and breadth of gait parameters provided in this study offer a unique reference resource for the researchers.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

La syncope est un symptôme clinique fréquent mais son origine demeure indéterminée jusque dans 60% des cas de patients admis dans un centre d'urgences. Le développement de consultations spécialisées de la syncope a considérablement modifié l'évaluation des patients avec une syncope inexpliquée en les orientant vers des stratégies d'investigations non-invasives, tels que le tilt-test, le massage du sinus carotidien et le test ^hyperventilation. Cependant, il existe peu de données dans 10 la littérature concernant dans la performance diagnostique réelle de ces tests fonctionnels.Notre travail de recherche porte sur l'analyse des données des 939 premiers patients adressés à la consultation ambulatoire de la syncope du CHUV pour l'investigation d'une syncope d'origine indéterminée. L'objectif de notre travail de thèse est 1) d'évaluer la performance diagnostique de l'algorithme de prise en charge standardisé et de ses différents tests pratiqués dans le cadre de notre 15 consultation et 2) de déterminer les caractéristiques cliniques communes des patients avec un diagnostic final de syncope d'origine rythmique ou vaso-vagale.Notre travail de thèse démontre qu'un algorithme de prise en charge standardisé basé sur des tests non-invasifs permet de déterminer 2/3 des causes de syncope initialement d'origine indéterminée. Par ailleurs, notre travail montre que des étiologies bénignes, telles que la syncope d'origine vaso- 20 vagale ou psychogène, représentent la moitié des causes syncopales alors que les arythmies cardiaques demeurent peu fréquentes. Finalement, notre travail démontre que l'absence de symptomatologie prodromique, en particulier chez les patients âgés avec une limitation fonctionnelle ou un allongement de la durée de l'onde Ρ à l'électrocardiogramme, suggère une syncope d'origine rythmique. Ce travail de thèse contribuera à optimaliser notre algorithme de prise 25 en charge standardisée de la syncope d'origine indéterminée et ouvre de nouvelles perspectives de recherche dans le développement de modèles basés sur des facteurs cliniques permettant de prédire les principales causes syncopales.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

All manner of foreign bodies have been extracted from the bladder. Introduction into the bladder may be through self-insertion, iatrogenic means or migration from adjacent organs. Extraction should be tailored according to the nature of the foreign body and should minimise bladder and urethral trauma. We report a case of a bullet injury to the bladder, which finally presented as a gross hematuria after remaining asymptomatic for four years. We present here an alternative to suprapubic cystostomy with a large bladder foreign body treated via a combined transurethral unroofing followed by removal using a grasper passed through a suprapubic laparoscopic port.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Red light running continues to be a serious safety concern for many communities in the United States. The Federal Highway Administration reported that in 2011, red light running accounted for 676 fatalities nationwide. Red light running crashes at a signalized intersections are more serious, especially in high speed corridors where speeds are above 35 mph. Many communities have invested in red light countermeasures including low-cost strategies (e.g. signal backplates, targeted enforcement, signal timing adjustments and improvement with signage) to high-cost strategies (e.g. automated enforcement and intersection geometric improvements). This research study investigated intersection confirmation lights as a low-cost strategy to reduce red light running violations. Two intersections in Altoona and Waterloo, Iowa were equipped with confirmation lights which targeted the through and left turning movements. Confirmation lights enable a single police officer to monitor a specific lane of traffic downstream of the intersection. A before-after analysis was conducted in which a change in red light running violations prior to- and 1 and 3 months after installation were evaluated. A test of proportions was used to determine if the change in red light running violation rates were statistically significant at the 90 and 95 percent levels of confidence. The two treatment intersections were then compared to the changes of red light running violation rates at spillover intersections (directly adjacent to the treatment intersections) and control intersections. The results of the analysis indicated a 10 percent reduction of red light running violations in Altoona and a 299 percent increase in Waterloo at the treatment locations. Finally, the research team investigated the time into red for each observed red light running violation. The analysis indicated that many of the violations occurred less than one second into the red phase and that most of the violation occurred during or shortly after the all-red phase.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Myeloid cell leukemia-1 (MCL1) is an anti-apoptotic member of the BCL2 family that is deregulated in various solid and hematological malignancies. However, its role in the molecular pathogenesis of diffuse large B-cell lymphoma (DLBCL) is unclear. We analyzed gene expression profiling data from 350 DLBCL patient samples and detected that activated B-cell-like (ABC) DLBCLs express MCL1 at significantly higher levels compared with germinal center B-cell-like DLBCL patient samples (P=2.7 × 10(-10)). Immunohistochemistry confirmed high MCL1 protein expression predominantly in ABC DLBCL in an independent patient cohort (n=249; P=0.001). To elucidate molecular mechanisms leading to aberrant MCL1 expression, we analyzed array comparative genomic hybridization data of 203 DLBCL samples and identified recurrent chromosomal gains/amplifications of the MCL1 locus that occurred in 26% of ABC DLBCLs. In addition, aberrant STAT3 signaling contributed to high MCL1 expression in this subtype. Knockdown of MCL1 as well as treatment with the BH3-mimetic obatoclax induced apoptotic cell death in MCL1-positive DLBCL cell lines. In summary, MCL1 is deregulated in a significant fraction of ABC DLBCLs and contributes to therapy resistance. These data suggest that specific inhibition of MCL1 might be utilized therapeutically in a subset of DLBCLs.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Lime sludge, an inert material mostly composed of calcium carbonate, is the result of softening hard water for distribution as drinking water. A large city such as Des Moines, Iowa, produces about 30,700 tons of lime sludge (dry weight basis) annually (Jones et al., 2005). Eight Iowa cities representing, according to the United States (U.S.) Census Bureau, 23% of the state’s population of 3 million, were surveyed. They estimated that they collectively produce 64,470 tons of lime sludge (dry weight basis) per year, and they currently have 371,800 tons (dry weight basis) stockpiled. Recently, the Iowa Department of Natural Resources directed those cities using lime softening in drinking water treatment to stop digging new lagoons to dispose of lime sludge. Five Iowa cities with stockpiles of lime sludge funded this research. The research goal was to find useful and economical alternatives for the use of lime sludge. Feasibility studies tested the efficacy of using lime sludge in cement production, power plant SOx treatment, dust control on gravel roads, wastewater neutralization, and in-fill materials for road construction. Applications using lime sludge in cement production, power plant SOx treatment, and wastewater neutralization, and as a fill material for road construction showed positive results, but the dust control application did not. Since the fill material application showed the most promise in accomplishing the project’s goal within the time limits of this research project, it was chosen for further investigation. Lime sludge is classified as inorganic silt with low plasticity. Since it only has an unconfined compressive strength of approximately 110 kPa, mixtures with fly ash and cement were developed to obtain higher strengths. When fly ash was added at a rate of 50% of the dry weight of the lime sludge, the unconfined strength increased to 1600 kPa. Further, friction angles and California Bearing Ratios were higher than those published for soils of the same classification. However, the mixtures do not perform well in durability tests. The mixtures tested did not survive 12 cycles of freezing and thawing and wetting and drying without excessive mass and volume loss. Thus, these mixtures must be placed at depths below the freezing line in the soil profile. The results demonstrated that chemically stabilized lime sludge is able to contribute bulk volume to embankments in road construction projects.