A coinfection model for HIV and HCV

We study a mathematical model for the human immunodeficiency virus (HIV) and hepatites C virus (HCV) coinfection. The model predicts four distinct equilibria: the disease free, the HIV endemic, the HCV endemic, and the full endemic equilibria. The local and global stability of the disease free equilibrium was calculated for the full model and the HIV and HCV submodels. We present numerical simulations of the full model where the distinct equilibria can be observed. We show simulations of the qualitative changes of the dynamical behavior of the full model for variation of relevant parameters. From the results of the model, we infer possible measures that could be implemented in order to reduce the number of infected individuals

A Novel Approach to Optimize the Design of Parts for Additive Manufacturing

Additive Manufacturing (AM) is a term used to group the different manufacturing processes that use various techniques, each of which is capable of producing parts made from a wide variety of materials, such as polymers, ceramics, metals, wood, among others. All these technologies allow parts manufacturing by adding successive layers of material which can be liquid, powder or wire. In order to take advantages of the geometric freedom offered by AM, Topological Optimization (TO) is usually used. TO provides the optimal distribution of material for a given request. The main objective is weight reduction, without compromising the original resistance of an existing part produced by traditional processes. Taking advantage of the freedom allowed by the AM process and conciliating it with the CAE features, which allow to simulate the parts behavior when subjected to the expected loads, a new approach methodology was drawn in order to shorten the time needed to optimize parts design for AM. A case study was developed in order to validate the methodology established. The combination of AM and TO revealed promising results, attending to the component efficiency achieved.info:eu-repo/semantics/publishedVersio

Improving the Cut Surface Quality by Optimizing Parameters in the Fibre Laser Cutting Process

One of the main problems with laser cutting equipment is related to the wrong setting of cutting parameters. The mismatching of these parameters leads to a loss of cut surface quality, which is hardly re-established. This loss of quality is usually related to a burr problem. Thus, this study is aimed to improve and optimize this process using a fibre laser equipment. Three important laser cutting parameters were studied in order to investigate their importance in the cut surface quality: radiation power, cutting speed and gas pressure. The different values were performed cutting a stainless steel AISI 316L and a cold rolled steel St12. Metallographic and cut surface analysis, burr and roughness measurements were carried out, supported by a Scanning Electron Microscopy and profilometry. Through the Taguchi statistical analysis model, it is possible to indicate the best set of laser cutting parameters. It was verified that the values recommended by the equipment manufacturer can be optimized, being possible to use less radiation power in the laser beam with greater speed of cut, providing a better cut surface quality, improving and optimizing the entire process.info:eu-repo/semantics/publishedVersio

The Improvement of an APEX Machine involved in the Tire Manufacturing Process

Over the years, there has been a huge expansion in the automotive component industry and its consequent innovation, which has evolved along with automation and robotics. Therefore, in order to ensure component quality, as well as the quality of the entire production process, it is crucial to enhance competitiveness in the sector. Since quality is a key feature in this industry, all manufacturers and suppliers are scrutinized by systematic audits to ensure constant improvements. This work was developed at a multinational industry and focuses on tire production for the automotive sector. Tires present a complex production process, which covers a wide range of activities from mixing, preparation, construction and vulcanization to the inspection departments, all of which are greatly predisposed to process improvement. In one of these departments (Preparation - APEX machines, responsible for the tire bead production), one of the main problems detected was directly related to a large number of failures in the pneumatic systems. These were found to be difficult to control, both in terms of speed and positioning. Some of the failures in automation were generating delays in certain processes, leading to lengthy setup times and culminating in higher production costs. In order to achieve greater quality, reliability and accuracy, a higher level of automation was applied to these kinds of machines by resorting to 5S methodology. A safety upgrade of the equipment was also undertaken, which will allow for the improvement of workplace safety.The performance improvement of the APEX machines was reached by implementing the following strategies: the automation of conveyor and tray movements between the cutting and application subprocesses; the implementation of 5S methodology; the automation of the cutting process; the updating of safety devices; and the automated control of the separation subprocess. A strong decrease in the breakdown time was recorded (-62%) resulting of the project implementation. The APEXmachine performance was also improved in 9%.info:eu-repo/semantics/publishedVersio

Radiative corrections to the Casimir effect for the massive scalar field

We compute the $O(\lambda)$ correction to the Casimir energy for the massive $\lambda\phi^4$ model confined between a pair of parallel plates. The calculations are made with Dirichlet and Neumann boundary conditions. The correction is shown to be sensitive to the boundary conditions, except in the zero mass limit, in which case our results agree with those found in the literature.Comment: 6 pages. Work presented at the XXIII Brazilian National Meeting on Particles and Fields (Aguas de Lindoia, Brazil, 15-19 Oct 2002). Also available at http://www.sbf1.if.usp.br/eventos/enfpc/xxiii/procs/RES142.pd

MAXIMUM NUMBER OF REPETITIONS, TOTAL WEIGHT LIFTED AND NEUROMUSCULAR FATIGUE IN INDIVIDUALS WITH DIFFERENT TRAINING BACKGROUNDS

The aim of this study was to evaluate the performance, as well as neuromuscular activity, in a strength task in subjects with different training backgrounds. Participants (n = 26) were divided into three groups according to their training backgrounds (aerobic, strength or mixed) and submitted to three sessions: (1) determination of the maximum oxygen uptake during the incremental treadmill test to exhaustion and familiarization of the evaluation of maximum strength (1RM) for the half squat; (2) 1RM determination; and (3) strength exercise, four sets at 80�0of the 1RM, in which the maximum number of repetitions (MNR), the total weight lifted (TWL), the root mean square (RMS) and median frequency (MF) of the electromyographic (EMG) activity for the second and last repetition were computed. There was an effect of group for MNR, with the aerobic group performing a higher MNR compared to the strength group (P = 0.045), and an effect on MF with a higher value in the second repetition than in the last repetition (P = 0.016). These results demonstrated that individuals with better aerobic fitness were more fatigue resistant than strength trained individuals. The absence of differences in EMG signals indicates that individuals with different training backgrounds have a similar pattern of motor unit recruitment during a resistance exercise performed until failure, and that the greater capacity to perform the MNR probably can be explained by peripheral adaptations

Hematopoietic stem cell transplantation is effective curative treatment in pediatric refractory/aggressive Langerhans cell histiocytosis

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Comparative efficacy between atorvastatin and rosuvastatin in the prevention of cardiovascular disease recurrence

Background: There is no randomized clinical trials with recurrence of atherosclerotic cardiovascular disease (ASCVD) as a major outcome with rosuvastatin. In order to analyze potential differences in the clinical response to atorvastatin and rosuvastatin in secondary ASCVD prevention, we have analyzed the clinical evolution of those subjects of the Dyslipemia Registry of the Spanish Society of Arteriosclerosis (SEA) who at the time of inclusion in the Registry had already suffered an ASCVD. Methods: This observational, retrospective, multicenter, national study was designed to determine potential differences between the use of atorvastatin and rosuvastatin in the ASCVD recurrence. Three different follow-up start-times were performed: time of inclusion in the registry; time of first event if this occurred after 2005, and time of first event without date restriction. Results: Baseline characteristics were similar between treatment groups. Among atorvastatin or rosuvastatin users, 89 recurrences of ASCVD were recorded (21.9%), of which 85.4% were coronary. At the inclusion of the subject in the registry, 345 participants had not suffered a recurrence yet. These 345 subjects accumulated 1050 person-years in a mean follow-up of 3 years. Event rates were 2.73 (95% CI: 1.63, 4.25) cases/100 person-years and 2.34 (95% CI: 1.17, 4.10) cases/100 person-years in the atorvastatin and rosuvastatin groups, respectively. There were no statistically significant differences between the two groups independently of the follow-up start-time. Conclusions: This study does not find differences between high doses of rosuvastatin and atorvastatin in the recurrence of ASCVD, and supports their use as clinically equivalent in secondary prevention of ASCVD

carapa guianensis aubl. and Carapa procera DC. (meliaceae)] by insects in Amazon

The objectives of this study were to identify the insects associated to seed predation of Carapa guianensis and Carapa procera, to evaluate the seeds damage potential of these insects and the occurrence of vertical stratification in the predation of Carapa seeds. The study was carried out in C. guianensis and C. procera plantations at Reserva Florestal Ducke, Manaus, Amazonas State, Brazil. The seed samples from the ground were taken weekly, and the canopy samples were taken monthly from three different heights. To evaluate the effect of predation on germination, 30 non-predated seeds and 30 predated seeds were collected monthly from the ground at each plot, and the germination was monitored during a month. The results showed that Hypsipyla grandella and H. ferrealis (Lepidoptera: Pyralidae) are the main insect species associated to seed predation in C. procera and C. guianensis, with predation mean rates of 39% to 61,96%, respectively. Fruit and seed predation were observed inside the canopy vertical stratification of the two Carapa species. The seed predation in C. procera and C. guianensis by Hypsipyla spp. reduced the germination process. This study produced information on the association between C. procera and C. guianensis and the species of Hypsipyla