967 resultados para Lock-In


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We assess the robustness of previous findings on the determinants of terrorism. Using extreme bound analysis, the three most comprehensive terrorism datasets, and focusing on the three most commonly analyzed aspects of terrorist activity, i.e., location, victim, and perpetrator, we re-assess the effect of 65 proposed correlates. Evaluating around 13.4 million regressions, we find 18 variables to be robustly associated with the number of incidents occurring in a given country-year, 15 variables with attacks against citizens from a particular country in a given year, and six variables with attacks perpetrated by citizens of a particular country in a given year.

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There are some long-established biases in atmospheric models that originate from the representation of tropical convection. Previously, it has been difficult to separate cause and effect because errors are often the result of a number of interacting biases. Recently, researchers have gained the ability to run multiyear global climate model simulations with grid spacings small enough to switch the convective parameterization off, which permits the convection to develop explicitly. There are clear improvements to the initiation of convective storms and the diurnal cycle of rainfall in the convection-permitting simulations, which enables a new process-study approach to model bias identification. In this study, multiyear global atmosphere-only climate simulations with and without convective parameterization are undertaken with the Met Office Unified Model and are analyzed over the Maritime Continent region, where convergence from sea-breeze circulations is key for convection initiation. The analysis shows that, although the simulation with parameterized convection is able to reproduce the key rain-forming sea-breeze circulation, the parameterization is not able to respond realistically to the circulation. A feedback of errors also occurs: the convective parameterization causes rain to fall in the early morning, which cools and wets the boundary layer, reducing the land–sea temperature contrast and weakening the sea breeze. This is, however, an effect of the convective bias, rather than a cause of it. Improvements to how and when convection schemes trigger convection will improve both the timing and location of tropical rainfall and representation of sea-breeze circulations.

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This book introduces six general procedures for teaching grammar to learners of English as a second language. The procedures are designed to encourage learners to notice, explore and practice grammar in context. Each description and discussion of a procedure is followed by two sample lesson plans together with sample texts and worksheets. Teachers can either use these 'as is' or adapt them for their own students. The lessons are suitable for a wide range of students from beginning learners to advanced learners. A final chapter provides examples of lessons in which several procedures are combined. In addition, before each sample lesson plan, the grammar focus of the lesson is briefly explained for the teacher. These procedures all illustrate how grammar can be taught through texts, and they are based on an understanding of the latest research on pedagogical grammar and the role of language awareness and discovery in second language learning and provide teachers with principles they can apply in developing their own teaching materials and activities. The grammar explanations preceding each teaching plan provide a fresh look at English grammar drawing on work in systemic functional linguistics.

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This paper reports the results of a study comparing the interactional dynamics of face-to-face and on-line peer-tutoring in writing by university students in Hong Kong. Transcripts of face-to-face tutoring sessions, as well as logs of on-line sessions conducted by the same peer-tutors, were coded for speech functions using a system based on Halliday's functional-semantic view of dialogue. Results show considerable differences between the interactional dynamics in on-line and face-to-face tutoring sessions. In particular, face-to-face interactions involved more hierarchal encounters in which tutors took control of the discourse, whereas on-line interactions were more egalitarian, with clients controlling the discourse more. Differences were also found in the topics participants chose to focus on in the two modes, with issues of grammar, vocabulary, and style taking precedence in face-to-face sessions and more “global” writing concerns like content and process being discussed more in on-line sessions.

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Background: Physical and bioceramic incorporation surface treatments at the nanometer scale showed higher means of bone-to-implant contact (BIC) and torque values compared with surface topography at the micrometer scale; however, the literature concerning the effect of nanometer scale parameters is sparse. Purpose: The aim of this study was to evaluate the influence of two different implant surfaces on the percentage bone-to-implant contact (BIC%) and bone osteocyte density in the human posterior maxilla after 2 months of unloaded healing. Materials and Methods: The implants utilized presented dual acid-etched (DAE) surface and a bioceramic molecular impregnated treatment (Ossean(R), Intra-Lock International, Boca Raton, FL, USA) serving as control and test, respectively. Ten subjects (59 1 9 years of age) received two implants (one of each surface) during conventional implant surgery in the posterior maxilla. After the non-loaded period of 2 months, the implants and the surrounding tissue were removed by means of a trephine and were non-decalcified processed for ground sectioning and analysis of BIC%, bone density in threaded area (BA%), and osteocyte index (Oi). Results: Two DAE implants were found to be clinically unstable at time of retrieval. Histometric evaluation showed significantly higher BIC% and Oi for the test compared to the control surface (p < .05), and that BA% was not significantly different between groups. Wilcoxon matched pairs test was used to compare the differences of histomorphometric variables between implant surfaces. The significance test was conducted at a 5% level of significance. Conclusion: The histological data suggest that the bioceramic molecular impregnated surface-treated implants positively modulated bone healing at early implantation times compared to the DAE surface.

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There is worldwide recognition that the burden of noncommunicable diseases (NCDs) and obesity-related health problems is rapidly increasing in low- and middle-income countries. Environmental determinants of obesity are likely to differ between countries, particularly in those undergoing rapid socioeconomic and nutrition transitions such as Brazil. This study aims to describe some built environment and local food environment variables and to explore their association with the overweight rate and diet and physical activity area-level aggregated indicators of adults living in the city of Sao Paulo, the largest city in Brazil. This formative study includes an ecological analysis of environmental factors associated with overweight across 31 submunicipalities of the city of Sao Paulo using statistical and spatial analyses. Average prevalence of overweight was 41.69% (95% confidence interval 38.74, 44.64), ranging from 27.14% to 60.75% across the submunicipalities. There was a wide geographical variation of both individual diet and physical activity, and indicators of food and built environments, favoring wealthier areas. After controlling for area socioeconomic status, there was a positive correlation between regular fruits and vegetables (FV) intake and density of FV specialized food markets (r = 0.497; p < 0.001), but no relationship between fast-food restaurant density and overweight prevalence was found. A negative association between overweight prevalence and density of parks and public sport facilities was seen (r = -0.527; p < 0.05). Understanding the relationship between local neighborhood environments and increasing rates of poor diet, physical activity, and obesity is essential in countries undergoing rapid economic and urban development, such as Brazil, in order to provide insights for policies to reduce increasing rates of NCDs and food access and health inequalities.

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The superposition of optical interference patterns in a photoresist film can produce a rich variety of diffractive structures. In particular, a periodic non-sinusoidal surface relief profile can be synthesized by adding the Fourier components (sinusoidal gratings) of the desired profile. In order to control the shape of the grooves it is very important an accurate adjustment of the relative spatial shift between the recorded sinusoidal components. We describe the implementation of an opto-electronic feedback loop to select and lock such spatial shift at any desired position, thus allowing the synthesis of structures varying from symmetrical to asymmetrical relief profiles in a continuous range. To demonstrate the feasibility of the technique, the Fourier synthesis of two spatial harmonics is accomplished. The superposed sinusoidal gratings were recorded in positive photoresist films using a holographic setup operating at the line lambda = 457.9 run of an argon-ion laser. A detailed description of the procedure as well as the resulting profiles recorded in the photoresist is presented. (C) 2002 Elsevier B.V. B.V. All rights reserved.

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The upcoming solar maximum, which is expected to reach its peak around May 2013, occurs at a time when our reliance on high-precision GNSS has reached unprecedented proportions. The perturbations of the ionosphere caused by increased solar activity pose a major threat to these applications. This is particularly true in equatorial regions where high exposure to solar-induced disturbances is coupled with explosive growth of precise GNSS applications. Along with the various types of solar-induced ionospheric disturbances, strong scintillations are amongst the most challenging, causing phase measurement errors up to full losses of lock for several satellites. Brazil, which heavily relies on high-precision GNSS, is one of the most affected regions due notably to the proximity to the southern crest of the ionospheric equatorial anomaly and to the South Atlantic Magnetic Anomaly. In the framework of the CIGALA project, we developed the PolaRxS™, a GNSS receiver dedicated to the monitoring of ionospheric scintillation indices not only in the GPS L1 band but for all operational and upcoming constellations and frequency bands. A network of these receivers was deployed across the whole Brazilian territory in order to first investigate and secondly to mitigate the impact of scintillation on the different signals, ensuring high precision GNSS availability and integrity in the area. This paper reports on the validation of the PolaRxS™ receiver as an ionospheric scintillation monitor and the first results of the analysis of the data collected with the CIGALA network.

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Transactional memory (TM) is a new synchronization mechanism devised to simplify parallel programming, thereby helping programmers to unleash the power of current multicore processors. Although software implementations of TM (STM) have been extensively analyzed in terms of runtime performance, little attention has been paid to an equally important constraint faced by nearly all computer systems: energy consumption. In this work we conduct a comprehensive study of energy and runtime tradeoff sin software transactional memory systems. We characterize the behavior of three state-of-the-art lock-based STM algorithms, along with three different conflict resolution schemes. As a result of this characterization, we propose a DVFS-based technique that can be integrated into the resolution policies so as to improve the energy-delay product (EDP). Experimental results show that our DVFS-enhanced policies are indeed beneficial for applications with high contention levels. Improvements of up to 59% in EDP can be observed in this scenario, with an average EDP reduction of 16% across the STAMP workloads. © 2012 IEEE.

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Catheter-related bacteremia (CRB) is one of the various complications related to hemodialysis (HD). As a result of this high rate of infection, the antibiotic lock technique (ALT) has been recommended to prevent CRB. However, adverse effects of ALT such as increased emergence of strains resistant to antibiotics and increased mechanical dysfunction catheter were poorly evaluated. We prospectively evaluated the efficacy of catheter-restricted filling using an antibiotic lock solution in preventing CRB. A total of 233 HD patients requiring 325 new tunneled catheters while waiting for placement and maturation of an arteriovenous fistula or graft were enrolled in this study. Patients with a tunneled catheter were assigned to receive either an antibiotic-heparin lock solution (antibiotic group: cefazolin 10 mg/ml, gentamicin 5 mg/ml, heparin 1,000 U/ml) or a heparin lock solution (no-antibiotic group: heparin 1,000 U/ml) as a catheter lock solution during the interdialytic period. The present study aimed to assess the efficacy of ALT using cefazolin and gentamicin in reducing CRB in patients undergoing HD with tunneled central catheter and to identify its adverse effects. CRB developed in 32.4 % of patients in the no-antibiotic group and in 13.1 % of patients in the antibiotic group. CRB rates per 1,000 catheter-days were 0.57 in the antibiotic group versus 1.74 in the no-antibiotic group (p < 0.0001). Kaplan-Meier analysis also showed that mean CRB-free catheter survival was significantly higher in the antibiotic group than in the no-antibiotic group (log-rank statistic 17.62, p < 0.0001). There was statistically significant difference between the two groups in causative organisms of CRB, with predominance of negative culture in both groups, but this prevalence was higher in ALT group (57.9 vs 90.1 %, p < 0.0001), and the two groups also were different in prevalence of gram-positive bacteria as causing organisms (ALT group 21.05 vs = 0 % in control group, p < 0.0001). There was no statistically significant difference between the two groups in drug-resistant germs. There were statistically significant differences between the two groups in the catheter removal causes, with higher rate of infectious cause in control group (12.32 vs 2.22 %, p < 0.0001) and mechanical cause in ALT group (28.26 vs 37.78 %, p < 0.0001). The results suggest that ALT may be a beneficial means of reducing the CRB rate in HD patients with tunneled catheter, without association between ALT and emergence of strains resistant. However, mechanical complications were more prevalent in antibiotic group. Further studies are required to determine the optimal drug regimen, concentrations for ALT, and its adverse effects. © 2012 Springer Science+Business Media Dordrecht.

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Temporomandibular joint (TMJ) disorder is a term that encompasses a number of overlapping conditions, such as closed lock. Closed lock of the TMJ is considered a consequence of a nonreducing deformed disc acting as an obstacle to the sliding condylar head that usually causes a decrease in the maximum mouth opening and acute pain. The management of the TMJ is still controversial. Thus, arthrocentesis of the TMJ is a valuable modification of the traditional method of arthroscopic lavage, which consists of washing the joint in order to remove chemical inflammatory mediators and intra-articular adhesions, changing intra-articular pressure. TMJ disorder has always presented as a therapeutic challenge to maxillofacial surgeons. Therefore, this paper aimed to describe a clinical report of a closed lock of the left TMJ in a 19-year-old female subject who was successfully treated by arthrocentesis procedure. © 2013 by Mutaz B. Habal, MD.

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Vascular access is the major risk factor for bacteremia, hospitalization, and mortality among hemodialysis (HD) patients. The type of vascular access most associated with bloodstream infection is central venous catheter (CVC). The incidence of catheter-related bacteremia ranges between 0.6 and 6.5 episodes per 1000 catheter days and increases linearly with the duration of catheter use. Given the high prevalence of CVC use and its direct association with catheter-related bacteremia, which adversely impacts morbidity and mortality rates and costs among HD patients, several prevention measures aimed at reducing the rates of CVC-related infections have been proposed and implemented. As a result, a large number of clinical trials, systematic reviews, and meta-analyses have been conducted in order to assess the effectiveness, clinical applicability, and long-term adverse effects of such measures. In the following article, prophylactic measures against CVC-related infections in HD patients and their possible advantages and limitations will be discussed, and the more recent literature on clinical experience with prophylactic antimicrobial lock therapy in HD CVCs will be reviewed.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Scintillations are rapid fluctuations in the phase and amplitude of transionospheric radio signals which are caused by small-scale plasma density irregularities in the ionosphere. In the case of the Global Navigation Satellite System (GNSS) receivers, scintillation can cause cycle slips, degrade the positioning accuracy and, when severe enough, can even lead to a complete loss of signal lock. Thus, the required levels of availability, accuracy, integrity and reliability for the GNSS applications may not be met during scintillation occurrence; this poses a major threat to a large number of modern-day GNSS-based applications. The whole of Latin America, Brazil in particular, is located in one of the regions most affected by scintillations. These effects will be exacerbated during solar maxima, the next predicted for 2013. This paper presents initial results from a research work aimed to tackle ionospheric scintillation effects for GNSS users in Latin America. This research is a part of the CIGALA (Concept for Ionospheric Scintillation Mitigation for Professional GNSS in Latin America) project, co-funded by the EC Seventh Framework Program and supervised by the GNSS Supervisory Authority (GSA), which aims to develop and test ionospheric scintillation countermeasures to be implemented in multi-frequency, multi-constellation GNSS receivers.

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Objectives: To investigate the effect of Si addition on a nanometer-scale roughness Ca and P implant surfaces in a canine tibia model by biomechanical and histomorphometric evaluations. Material and methods: The implant surfaces comprised a resorbable media CaP microblasted (control) and a CaP resorbable media + silica-boost microblasted (experimental) surfaces. Surfaces were characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and optical interferometry (IFM) down to the nanometric level. The animal model involved the bilateral placement of control (n = 24) and experimental surface (n = 24) implants along the proximal tibiae of six dogs, remaining in vivo for 2 or 4 weeks. After euthanization, half of the specimens were torquedto- interface failure, and the other half was subjected to histomorphologic and bone-to-implant contact (BIC) evaluation. Torque and BIC statistical evaluation was performed by the Friedman test at 95% level of significance, and comparisons between groups was performed by the Dunn test. Results: IFM and SEM observations depicted comparable roughness parameters for both implant surfaces on the micrometer and nanometer scales. XPS analysis revealed similar chemical composition, except for the addition of Si on the experimental group. Torque-to-interface failure and BIC mean values showed no significant differences (P = 0.25 and 0.51, respectively) at both 2- and 4-week evaluation points for experimental and control groups. Early bone healing histomorphologic events were similar between groups. Conclusions: The experimental surface resulted in not significantly different biomechanical fixation and BIC relative to control. Both surfaces were biocompatible and osseoconductive.