411 research outputs found

    Channel Division Multiple Access

    Full text link
    Ultra-WideBand (UWB) has been recently presented as a promising radio technology due to the large bandwidth available. This feature enables point to point high data rates at short range as well as high temporal resolution with long channel impulse reponses (CIR). In this paper, we present an original multiple access scheme called Channel Division Multiple Access (ChDMA), where we use the CIR as a user signature. The signature code is given by the channel and the users are separated by their position: this signature is uniquely determined by the user's position, which changes from one position to another. This signature location-dependent property provides decentralized flexible multiple access as the codes are naturally generated by the radio channel. The results derived can be straightforwardly applied to UWB ad-hoc networks. To analyze the multiple access scheme performance, we evaluate the channel capacity in a wideband power limited regime by the tradeoff of the spectral efficiency (b/s/hz) versus the ratio between the number of users and the system resolution. The framework is analyzed and validated by capacity assessments using UWB measurements performed at Eurecom and compared with classical CDMA schemes with random spreading. The following receivers are considered: optimal joint processing, single-user matched filter and MMSE receiver...

    Faster and slower posttraining recovery in futsal: Multifactorial classification of recovery profiles

    Full text link
    © 2019 Human Kinetics, Inc. Purpose: To investigate the existence of faster vs slower recovery profiles in futsal and factors distinguishing them. Methods: 22 male futsal players were evaluated in countermovement jump, 10-m sprint, creatine kinase, total quality of recovery (TQR), and Brunel Mood Scale (fatigue and vigor) before and immediately and 3, 24, and 48 h posttraining. Hierarchical cluster analysis allocated players to different recovery profiles using the area under the curve (AUC) of the percentage differences from baseline. One-way ANOVA compared the time course of each variable and players’ characteristics between clusters. Results: Three clusters were identified and labeled faster recovery (FR), slower physiological recovery (SLphy), and slower perceptual recovery (SLperc). FR presented better AUC in 10-m sprint than SLphy (P = .001) and SLperc (P = .008), as well as better TQR SLphy (P = .018) and SLperc (P = .026). SLperc showed better AUC in countermovement jump than SLphy (P = .014) but presented worse fatigue AUC than SLphy (P = .014) and FR (P = .008). AUC of creatine kinase was worse in SLphy than in FR (P = .001) and SLperc (P < .001). The SLphy players were younger than SLperc players (P = .027), whereas FR were slower 10-m sprinters than SLphy players (P = .003) and SLperc (P = .013) and tended to have higher maximal oxygen consumption than SLphy (effect size = 1.13). Conclusion: Different posttraining recovery profiles exist in futsal players, possibly influenced by their physical abilities and age/experience

    Use of granulocyte growth factors: recommendations of the Portuguese Society of Hematology

    Get PDF
    The administration of cytotoxic chemotherapy may be complicated by the emergence of neutropenia and febrile neutropenia, frequently determining hospital admission and intravenous treatment with broad spectrum antibiotics. Frequently, it is necessary to reduce the dose or to delay the administration of the cytotoxic drugs reducing the relative dose intensity of the chemotherapy regimen. Granulocyte growth factors stimulate the proliferation and differentiation of neutrophils and reduce the number of days of severe neutropenia and febrile neutropenia associated with cytotoxic chemotherapy. They are also indicated for the collection of hematopoietic progenitors for autologous and allogeneic transplantation, as well as in non malignant diseases associated with chronic neutropenia. This article reviews the evidence supporting the use of granulocyte growth factors in Hematology

    Ecotoxicological assessment of irrigation water for vegetables in a watershed region of Greater São Paulo

    Get PDF
    The aim of the present study was to evaluate the quality of irrigation water for vegetables in a Greater São Paulo watershed region. Acute and chronic ecotoxicity bioassays with Dugesia tigrina and Selenastrum capricornutum and geno/mutagenicity assays with Allium cepa were performed, as well as microbiological assays for total and thermotolerant coliforms, according to the legislation. The ecotoxicological data did not show significant toxicity in any of the samples. However, surface water genotoxic effect was detected in 2 out of the 3 points and mutagenic effect in all three sampled points, as well as in the sediment, in the Allium cepa test. Such high prevalence of total and thermotolerant coliforms in all samples at the three points indicates a compromised environmental integrity of the basin due to high loads of organic pollution, probably of clandestine origin. No emissions of industrial origin were detected in the region. Thus, taken together, the results suggest that agricultural activity itself may account for the impacts in these water bodies. The present study represents a contribution to the scarce data available in the literature about this important Greater São Paulo region

    Hypoglycemic and anti-lipemic effects of the aqueous extract from Cissus sicyoides

    Get PDF
    BACKGROUND: Cissus sicyoides (Vitaceae) is a medicinal plant popularly known in Brazil as "cipó-pucá, anil-trepador, cortina, and insulina". The plant is used in several diseases, including rheumatism, epilepsy, stroke and also in the treatment of diabetes. In the present work, we studied the hypoglycemic and anti-lipemic effects of the aqueous extract prepared from fresh leaves of the plant (AECS), in the model of alloxan-induced diabetes in rats. In addition, hepatic enzyme levels were also determined. RESULTS: Results showed that the daily treatment of diabetic rats with AECS for 7 days (100 and 200 mg/kg, p.o.) significantly decreased blood glucose levels in 25 and 22% respectively, as compared to the same groups before AECS treatment. No significant changes were seen in control diabetic rats before (48 h after alloxan administration) and after distilled water treatment. While no changes were seen in total cholesterol levels, a significant decrease was observed in plasma triglyceride levels, in the alloxan-induced diabetic rats after AECS treatment with both doses, as compared to the same groups before treatment. Significant decreases in blood glucose (25%) and triglyceride levels (48%) were also observed in the alloxan-induced diabetic rats after 4 days treatment with AECS (200 mg/kg, p.o.). Aspartate (AST) and alanine (ALT) aminotransferases levels, in diabetic controls and AECS-treated rats, were in the range of reference values presented by normal rats. CONCLUSIONS: The results justify the popular use of C. sicyoides, pointing out to the potential benefit of the plant aqueous extract (AECS) in alternative medicine, in the treatment of type 2 diabetes mellitus

    Risk Factors and Characterization of Plasmodium Vivax-Associated Admissions to Pediatric Intensive Care Units in the Brazilian Amazon

    Get PDF
    BACKGROUND: Plasmodium vivax is responsible for a significant proportion of malaria cases worldwide and is increasingly reported as a cause of severe disease. The objective of this study was to characterize severe vivax disease among children hospitalized in intensive care units (ICUs) in the Western Brazilian Amazon, and to identify risk factors associated with disease severity. METHODS AND FINDINGS: In this retrospective study, clinical records of 34 children, 0-14 years of age hospitalized in the 11 public pediatric and neonatal ICUs of the Manaus area, were reviewed. P. falciparum monoinfection or P. falciparum/P. vivax mixed infection was diagnosed by microscopy in 10 cases, while P. vivax monoinfection was confirmed in the remaining 24 cases. Two of the 24 patients with P. vivax monoinfection died. Respiratory distress, shock and severe anemia were the most frequent complications associated with P. vivax infection. Ninety-one children hospitalized with P. vivax monoinfections but not requiring ICU were consecutively recruited in a tertiary care hospital for infectious diseases to serve as a reference population (comparators). Male sex (p = 0.039), age less than five years (p = 0.028), parasitemia greater than 500/mm(3) (p = 0.018), and the presence of any acute (p = 0.023) or chronic (p = 0.017) co-morbidity were independently associated with ICU admission. At least one of the WHO severity criteria for malaria (formerly validated for P. falciparum) was present in 23/24 (95.8%) of the patients admitted to the ICU and in 17/91 (18.7%) of controls, making these criteria a good predictor of ICU admission (p = 0.001). The only investigated criterion not associated with ICU admission was hyperbilirubinemia (p = 0.513)]. CONCLUSIONS: Our study points to the importance of P. vivax-associated severe disease in children, causing 72.5% of the malaria admissions to pediatric ICUs. WHO severity criteria demonstrated good sensitivity in predicting severe P. vivax infection in this small case series

    Zebra finches and Dutch adults exhibit the same cue weighting bias in vowel perception

    Get PDF
    Vocal tract resonances, called formants, are the most important parameters in human speech production and perception. They encode linguistic meaning and have been shown to be perceived by a wide range of species. Songbirds are also sensitive to different formant patterns in human speech. They can categorize words differing only in their vowels based on the formant patterns independent of speaker identity in a way comparable to humans. These results indicate that speech perception mechanisms are more similar between songbirds and humans than realized before. One of the major questions regarding formant perception concerns the weighting of different formants in the speech signal (“acoustic cue weighting”) and whether this process is unique to humans. Using an operant Go/NoGo design, we trained zebra finches to discriminate syllables, whose vowels differed in their first three formants. When subsequently tested with novel vowels, similar in either their first formant or their second and third formants to the familiar vowels, similarity in the higher formants was weighted much more strongly than similarity in the lower formant. Thus, zebra finches indeed exhibit a cue weighting bias. Interestingly, we also found that Dutch speakers when tested with the same paradigm exhibit the same cue weighting bias. This, together with earlier findings, supports the hypothesis that human speech evolution might have exploited general properties of the vertebrate auditory system
    corecore