Application of ionospheric corrections in the equatorial region for L1 GPS users

In the absence of the selective availability, which was turned off on May 1, 2000, the ionosphere can be the largest source of error in GPS positioning and navigation. Its effects on GPS observable cause a code delays and phase advances. The magnitude of this error is affected by the local time of the day, season, solar cycle, geographical location of the receiver and Earth's magnetic field. As it is well known, the ionosphere is the main drawback for high accuracy positioning, when using single frequency receivers, either for point positioning or relative positioning of medium and long baselines. The ionosphere effects were investigated in the determination of point positioning and relative positioning using single frequency data. A model represented by a Fourier series type was implemented and the parameters were estimated from data collected at the active stations of RBMC (Brazilian Network for Continuous Monitoring of GPS satellites). The data input were the pseudorange observables filtered by the carrier phase. Quality control was implemented in order to analyse the adjustment and to validate the significance of the estimated parameters. Experiments were carried out in the equatorial region, using data collected from dual frequency receivers. In order to validate the model, the estimated values were compared with ground truth. For point and relative positioning of baselines of approximately 100 km, the values of the discrepancies indicated an error reduction better than 80% and 50% respectively, compared to the processing without the ionospheric model. These results give an indication that more research has to be done in order to provide support to the L1 GPS users in the Equatorial region.

RINEX_HO: second- and third-order ionospheric corrections for RINEX observation files

When GNSS receivers capable of collecting dual-frequency data are available, it is possible to eliminate the first-order ionospheric effect in the data processing through the ionosphere-free linear combination. However, the second- and third-order ionospheric effects still remain. The first-, second- and third-order ionospheric effects are directly proportional to the total electron content (TEC), although the second- and third-order effects are influenced, respectively, by the geomagnetic field and the maximum electron density. In recent years, the international scientific community has given more attention to these kinds of effects and some works have shown that for high precision GNSS positioning these effects have to be taken into consideration. We present a software tool called RINEX_HO that was developed to correct GPS observables for second- and third-order ionosphere effects. RINEX_HO requires as input a RINEX observation file, then computes the second- and third-order ionospheric effects, and applies the corrections to the original GPS observables, creating a corrected RINEX file. The mathematical models implemented to compute these effects are presented, as well as the transformations involving the earth's magnetic field. The use of TEC from global ionospheric maps and TEC calculated from raw pseudorange measurements or pseudoranges smoothed by phase is also investigated.

Differential antibody isotype expression to the major Paracoccidioides brasiliensis antigen in juvenile and adult form paracoccidioidomycosis

We investigated the relationship between antibody response to the major Paracoccidioides brasiliensis antigen, a 43-kDa glycoprotein, and the two paracoccidioidomycosis (PCM) clinical presentations, the juvenile and the adult forms. Total immunoglobulin G (IgG), IgG isotypes, and IgA anti-gp43 antibodies were determined by enzyme-linked immunosorbent assay in patients' sera. Juvenile PCM patients had higher (P =.003) IgG anti-gp43 levels than adult form patients. IgG1 subclass levels, however, were comparable between the two clinical forms. Patients with the juvenile form had higher (P <.001) IgG4, but lower(P =.03) IgG2 levels than patients with the adult form. The IgG4 isotype, regulated by interleukin 4, was found in all juvenile form patients but in only 12% of the adult form patients. In contrast, high levels of the IgG2 isotype, regulated by interferon-gamma, were found in 41% of the adult PCM patients, mainly those with a more benign disease, but in only 12% of the juvenile patients. IgG3 was either absent or detected at low levels. These results demonstrate, for the first time, specific IgG4 antibodies in the humoral immune response of patients with an endemic deep mycosis and suggest that the switch to the IgG subclasses in PCM is regulated by the patients' T-helper subset (Th-l or Th-2) dominant cytokine profile. A possible role for IgG4 in the immunopathogenesis of the juvenile, more severe form of the disease is discussed. Finally, IgA was found mainly in adult form patients, probably as a result of the chronic mucosal antigenic stimulation characteristic of this form. (C) Elsevier, Paris.

Black string corrections in variable tension braneworld scenarios

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Optimal attitude corrections for cylindrical spacecraft

A first order analytical model for optimal small amplitude attitude maneuvers of spacecraft with cylindrical symmetry in an elliptical orbits is presented. The optimization problem is formulated as a Mayer problem with the control torques provided by a power limited propulsion system. The state is defined by Seffet-Andoyer's variables and the control by the components of the propulsive torques. The Pontryagin Maximum Principle is applied to the problem and the optimal torques are given explicitly in Serret-Andoyer's variables and their adjoints. For small amplitude attitude maneuvers, the optimal Hamiltonian function is linearized around a reference attitude. A complete first order analytical solution is obtained by simple quadrature and is expressed through a linear algebraic system involving the initial values of the adjoint variables. A numerical solution is obtained by taking the Euler angles formulation of the problem, solving the two-point boundary problem through the shooting method, and, then, determining the Serret-Andoyer variables through Serret-Andoyer transformation. Numerical results show that the first order solution provides a good approximation to the optimal control law and also that is possible to establish an optimal control law for the artificial satellite's attitude. (C) 2003 COSPAR. Published by Elsevier B.V. Ltd. All rights reserved.

Structural abnormalities of the thalamus in juvenile myoclonic epilepsy

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

Tumor microenvironmental genomic alterations in juvenile nasopharyngeal angiofibroma

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

Remission status follow-up in children with juvenile idiopathic arthritis

Objective: To characterize articular and systemic inflammatory activity in juvenile idiopathic arthritis (JIA), identifying remission status with and without medication.Methods: A total of 165 JIA cases, followed for a mean period of 3.6 years, were reviewed in order to characterize episodes of inactivity and clinical remission on and off medication. The resulting data were analyzed by means of descriptive statistics, survival analysis, by comparison of Kaplan-Meier curves, log rank testing and binary logistic regression;analysis in order to identify predictive factors for remission or persistent activity.Results: One hundred and eight of the cases reviewed fulfilled the inclusion criteria: 57 patients (52.7%) exhibited a total of 71 episodes of inactivity, with a mean of 2.9 years per episode; 36 inactivity episodes (50.7%) resulted in clinical remission off medication, 35% of which were of the persistent oligoarticular subtype. The probability of clinical remission on medication over 2 years was 81, 82, 97 and 83% for cases of persistent oligoarticular, extended oligoarticular, polyarticular and systemicJIA, respectively. The probability of clinical remission off medication 5 years after onset of remission was 40 and 67% for patients with persistent oligoarticular and systemic JIA, respectively. Persistent disease activity was significantly associated with the use of an anti-rheumatic drug combination. Age at JIA onset was the only factor that predicted clinical remission (p = 0.002).Conclusions: In this cohort, the probability of JIA progressing to clinical remission was greater for the persistent oligoarticular and systemic subtypes, when compared with polyarticular cases.

Progression of articular and extraarticular damage in oligoarticular juvenile idiopathic arthritis

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

A Brazilian registry of juvenile dermatomyositis: onset features and classification of 189 cases

ObjectiveTo describe onset features, classification and treatment of juvenile dermatomyositis (JDM) and juvenile polymyositis (JPM) from a multicentre registry.MethodsInclusion criteria were onset age lower than 18 years and a diagnosis of any idiopathic inflammatory myopathy (IIM) by attending physician. Bohan & Peter (1975) criteria categorisation was established by a scoring algorithm to define JDM and JPM based oil clinical protocol data.ResultsOf the 189 cases included, 178 were classified as JDM, 9 as JPM (19.8: 1) and 2 did not fit the criteria; 6.9% had features of chronic arthritis and connective tissue disease overlap. Diagnosis classification agreement occurred in 66.1%. Medial? onset age was 7 years, median follow-up duration was 3.6 years. Malignancy was described in 2 (1.1%) cases. Muscle weakness occurred in 95.8%; heliotrope rash 83.5%; Gottron plaques 83.1%; 92% had at least one abnormal muscle enzyme result. Muscle biopsy performed in 74.6% was abnormal in 91.5% and electromyogram performed in 39.2% resulted abnormal in 93.2%. Logistic regression analysis was done in 66 cases with all parameters assessed and only aldolase resulted significant, as independent variable for definite JDM (OR=5.4, 95%CI 1.2-24.4, p=0.03). Regarding treatment, 97.9% received steroids; 72% had in addition at least one: methotrexate (75.7%), hydroxychloroquine (64.7%), cyclosporine A (20.6%), IV immunoglobulin (20.6%), azathioprine (10.3%) or cyclophosphamide (9.6%). In this series 24.3% developed calcinosis and mortality rate was 4.2%.ConclusionEvaluation of predefined criteria set for a valid diagnosis indicated aldolase as the most important parameter associated with de, methotrexate combination, was the most indicated treatment.

A new short and simple health-related quality of life measurement for paediatric rheumatic diseases: initial validation in juvenile idiopathic arthritis

Objective. To develop and validate a new short and simple measure of health-related quality of life (HRQL) in children with juvenile idiopathic arthritis (JIA).Methods. The Paediatric Rheumatology Quality of Life Scale (PRQL) is a 10-item questionnaire that explores HRQL in two domains: physical health (PhH) and psychosocial health (PsH). Validation of the parent proxy report and child self-report versions of the instrument was accomplished by evaluating 472 JIA patients and similar to 800 healthy children. Validation analyses included assessment of feasibility, face and content validity; construct and discriminative ability; internal structure and consistency; test-retest reliability; responsiveness to clinical change; and minimal clinically important difference.Results. The PRQL was found to be feasible and to possess both face and content validity. The PRQL score correlated in the predicted range with most of the other JIA outcome measures, thereby demonstrating good construct validity, and discriminated well between different levels of disease severity. Assessment of internal structure (factor analysis) revealed that the PhH and PsH subscales identify two unambiguously separated domains. The internal consistency (Cronbach's alpha) was 0.86. The intraclass correlation coefficient for test-retest reliability was 0.91. The PRQL revealed fair responsiveness, with a standardized response mean of 0.67 in improved patients. Overall, the PRQL appeared to be more able to capture physical HRQL than psychosocial HRQL.Conclusion. The PRQL was found to possess good measurement properties and is, therefore, a valid instrument for the assessment of HRQL in children with JIA. This tool is primarily proposed for use in standard clinical care.

Long-Term Safety and Efficacy of Abatacept in Children With Juvenile Idiopathic Arthritis

Objective. We previously documented that abatacept was effective and safe in patients with juvenile idiopathic arthritis (JIA) who had not previously achieved a satisfactory clinical response with disease-modifying antirheumatic drugs or tumor necrosis factor blockade. Here, we report results from the long-term extension (LTE) phase of that study.Methods. This report describes the long-term, open-label extension phase of a double-blind, randomized, controlled withdrawal trial in 190 patients with JIA ages 6-17 years. Children were treated with 10 mg/kg abatacept administered intravenously every 4 weeks, with or without methotrexate. Efficacy results were based on data derived from the 153 patients who entered the open-label LTE phase and reflect >= 21 months (589 days) of treatment. Safety results include all available open-label data as of May 7, 2008.Results. of the 190 enrolled patients, 153 entered the LTE. By day 589, 90%, 88%, 75%, 57%, and 39% of patients treated with abatacept during the double-blind and LTE phases achieved responses according to the American College of Rheumatology (ACR) Pediatric 30 (Pedi 30), Pedi 50, Pedi 70, Pedi 90, and Pedi 100 criteria for improvement, respectively. Similar response rates were observed by day 589 among patients previously treated with placebo. Among patients who had not achieved an ACR Pedi 30 response at the end of the open-label lead-in phase and who proceeded directly into the LTE, 73%, 64%, 46%, 18%, and 5% achieved ACR Pedi 30, Pedi 50, Pedi 70, Pedi 90, and Pedi 100 responses, respectively, by day 589 of the LTE. No cases of tuberculosis and no malignancies were reported during the LTE. Pneumonia developed in 3 patients, and multiple sclerosis developed in 1 patient.Conclusion. Abatacept provided clinically significant and durable efficacy in patients with JIA, including those who did not initially achieve an ACR Pedi 30 response during the initial 4-month open-label lead-in phase.

Hormone profile in juvenile systemic lupus erythematosus with previous or current amenorrhea

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Macrophage Activation Syndrome in Juvenile Systemic Lupus Erythematosus A Multinational Multicenter Study of Thirty-Eight Patients

Objective. To describe the clinical and laboratory features of macrophage activation syndrome as a complication of juvenile systemic lupus erythematosus (SLE).Methods. Cases of juvenile SLE-associated macrophage activation syndrome were provided by investigators belonging to 3 pediatric rheumatology networks or were found in the literature. Patients who had evidence of macrophage hemophagocytosis on bone marrow aspiration were considered to have definite macrophage activation syndrome, and those who did not have such evidence were considered to have probable macrophage activation syndrome. Clinical and laboratory findings in patients with macrophage activation syndrome were contrasted with those of 2 control groups composed of patients with active juvenile SLE without macrophage activation syndrome. The ability of each feature to discriminate macrophage activation syndrome from active disease was evaluated by calculating sensitivity, specificity, and area under the receiver operating characteristic curve.Results. The study included 38 patients (20 with definite macrophage activation syndrome and 18 with probable macrophage activation syndrome). Patients with definite and probable macrophage activation syndrome were comparable with regard to all clinical and laboratory features of the syndrome, except for a greater frequency of lymphadenopathy, leukopenia, and thrombocytopenia in patients with definite macrophage activation syndrome. Overall, clinical features had better specificity than sensitivity, except for fever, which was highly sensitive but had low specificity. Among laboratory features, the best sensitivity and specificity was achieved using hyperferritinemia, followed by increased levels of lactate dehydrogenase, hypertriglyceridemia, and hypofibrinogenemia. Based on the results of statistical analysis, preliminary diagnostic guidelines for macrophage activation syndrome in juvenile SLE were developed.Conclusion. Our findings indicate that the occurrence of unexplained fever and cytopenia, when associated with hyperferritinemia, in a patient with juvenile SLE should raise the suspicion of macrophage activation syndrome. We propose preliminary guidelines for this syndrome in juvenile SLE to facilitate timely diagnosis and correct classification of patients.

Differential MMP-2 and MMP-9 Activity and Collagen Distribution in Skeletal Muscle from pacu (Piaractus mesopotamicus) During Juvenile and Adult Growth Phases

Here, we evaluated collagen distribution and matrix metalloproteinases (MMPs) MMP-2 and MMP-9 activities in skeletal muscle of pacu (Piaractus mesopotamicus) during juvenile and adult growth phases. Muscle samples from juvenile and adult fishes were processed by histochemistry for collagen system fibers and for gelatin-zymography for MMP-2 and MMP-9 activities analysis. Picrosirius staining revealed a myosept, endomysium, and perimysium-like structures in both growth phases and muscle types, with increased areas of collagen fibers in adults, mainly in red muscle. Reticulin staining showed that reticular fibers in the endomysium-like structure were thinner and discontinuous in the red muscle fibers. The zymography revealed clear bands of the pro-MMP-9, active-MMP-9, intermediate-MMP-2, and active-MMP-2 forms in red and white muscle in both growth phases. MMP-2 activity was more intense in juvenile than adult muscle fibers. Comparing the red and white muscle types, MMP-2 activity was significantly higher in red muscle in adult phase only. The activity of MMP-9 forms was similar in juvenile red and white muscles and in the adult red muscle, without any activity in adult white muscle. In conclusion, our results show that, in pacu, the higher activities of MMP-2 and -9 are associated with the rapid muscle growth in juvenile age and in adult fish, these activities are related with a different red and white muscle physiology. This study may contribute to the understanding muscle growth mechanisms and may also contribute to analyse red and the white muscle parameters of firmness and softness, respectively, of the commercial product. Anat Rec, 292:387-395, 2009. (C) 2009 Wiley-Liss, Inc.