Guidelines for the development, performance evaluation and validation of new sleep technologies (DEVSleepTech guidelines) - a protocol for a Delphi consensus study.

New sleep technologies are being developed, refined and delivered at a fast pace. However, there are serious concerns about the validation and accuracy of new sleep-related technologies being made available, as many of them, especially consumer-sleep technologies, have not been tested in comparison with gold-standard methods or have been approved by health regulatory agencies. The importance of proper validation and performance evaluation of new sleep technologies has already been discussed in previous studies and some recommendations have already been published, but most of them do not employ standardized methodology and are not able to cover all aspects of new sleep technologies. The current protocol describes the methods of a Delphi consensus study to create guidelines for the development, performance evaluation and validation of new sleep devices and technologies. The resulting recommendations are not intended to be used as a quality assessment tool to evaluate individual articles, but rather to evaluate the overall procedures, studies and experiments performed to develop, evaluate performance and validate new technologies. We hope these guidelines can be helpful for researchers who work with new sleep technologies on the appraisal of their reliability and validation, for companies who are working on the development and refinement of new sleep technologies, and by regulatory agencies to evaluate new technologies that are looking for registration, approval or inclusion on health systems.

Consumer sleep technology for the screening of obstructive sleep apnea and snoring: current status and a protocol for a systematic review and meta-analysis of diagnostic test accuracy.

There are concerns about the validation and accuracy of currently available consumer sleep technology for sleep-disordered breathing. The present report provides a background review of existing consumer sleep technologies and discloses the methods and procedures for a systematic review and meta-analysis of diagnostic test accuracy of these devices and apps for the detection of obstructive sleep apnea and snoring in comparison with polysomnography. The search will be performed in four databases (PubMed, Scopus, Web of Science, and the Cochrane Library). Studies will be selected in two steps, first by an analysis of abstracts followed by full-text analysis, and two independent reviewers will perform both phases. Primary outcomes include apnea-hypopnea index, respiratory disturbance index, respiratory event index, oxygen desaturation index, and snoring duration for both index and reference tests, as well as the number of true positives, false positives, true negatives, and false negatives for each threshold, as well as for epoch-by-epoch and event-by-event results, which will be considered for the calculation of surrogate measures (including sensitivity, specificity, and accuracy). Diagnostic test accuracy meta-analyses will be performed using the Chu and Cole bivariate binomial model. Mean difference meta-analysis will be performed for continuous outcomes using the DerSimonian and Laird random-effects model. Analyses will be performed independently for each outcome. Subgroup and sensitivity analyses will evaluate the effects of the types (wearables, nearables, bed sensors, smartphone applications), technologies (e.g., oximeter, microphone, arterial tonometry, accelerometer), the role of manufacturers, and the representativeness of the samples.

Quantum transport on honeycomb networks.

We study the transport properties on honeycomb networks motivated by graphene structures by using the continuous-time quantum walk (CTQW) model. For various relevant topologies we consider the average return probability and its long-time average as measures for the transport efficiency. These quantities are fully determined by the eigenvalues and the eigenvectors of the connectivity matrix of the network. For all networks derived from graphene structures we notice a nontrivial interplay between good spreading and localization effects. Flat graphene with similar number of hexagons along both directions shows a decrease in transport efficiency compared to more one-dimensional structures. This loss can be overcome by increasing the number of layers, thus creating a graphite network, but it gets less efficient when rolling up the sheets so that a nanotube structure is considered. We found peculiar results for honeycomb networks constructed from square graphene, i.e. the same number of hexagons along both directions of the graphene sheet. For these kind of networks we encounter significant differences between networks with an even or odd number of hexagons along one of the axes.

Continuous-time quantum walks on multilayer dendrimer networks.

We consider continuous-time quantum walks (CTQWs) on multilayer dendrimer networks (MDs) and their application to quantum transport. A detailed study of properties of CTQWs is presented and transport efficiency is determined in terms of the exact and average return probabilities. The latter depends only on the eigenvalues of the connectivity matrix, which even for very large structures allows a complete analytical solution for this particular choice of network. In the case of MDs we observe an interplay between strong localization effects, due to the dendrimer topology, and good efficiency from the linear segments. We show that quantum transport is enhanced by interconnecting more layers of dendrimers.

Insulin Dose and Cardiovascular Mortality in the ACCORD Trial.

OBJECTIVE: In the ACCORD trial, intensive treatment of patients with type 2 diabetes and high cardiovascular (CV) risk was associated with higher all-cause and CV mortality. Post hoc analyses have failed to implicate rapid reduction of glucose, hypoglycemia, or specific drugs as the causes of this finding. We hypothesized that exposure to injected insulin was quantitatively associated with increased CV mortality. RESEARCH DESIGN AND METHODS: We examined insulin exposure data from 10,163 participants with a mean follow-up of 5 years. Using Cox proportional hazards models, we explored associations between CV mortality and total, basal, and prandial insulin dose over time, adjusting for both baseline and on-treatment covariates including randomized intervention assignment. RESULTS: More participants allocated to intensive treatment (79%) than standard treatment (62%) were ever prescribed insulin in ACCORD, with a higher mean updated total daily dose (0.41 vs. 0.30 units/kg) (P < 0.001). Before adjustment for covariates, higher insulin dose was associated with increased risk of CV death (hazard ratios [HRs] per 1 unit/kg/day 1.83 [1.45, 2.31], 2.29 [1.62, 3.23], and 3.36 [2.00, 5.66] for total, basal, and prandial insulin, respectively). However, after adjustment for baseline covariates, no significant association of insulin dose with CV death remained. Moreover, further adjustment for severe hypoglycemia, weight change, attained A1C, and randomized treatment assignment did not materially alter this observation. CONCLUSIONS: These analyses provide no support for the hypothesis that insulin dose contributed to CV mortality in ACCORD.

Intensive care unit readmission during childhood after preterm birth with respiratory failure.

OBJECTIVE: To determine the incidence and risk factors for readmission to the intensive care unit (ICU) among preterm infants who required mechanical ventilation at birth. STUDY DESIGN: We studied preterm newborns (birth weight 500-1250 g) who required mechanical ventilation at birth and were enrolled in a multicenter trial of inhaled nitric oxide therapy. Patients were assessed up to 4.5 years of age via annual in-person evaluations and structured telephone interviews. Univariate and multivariable analyses of baseline and birth hospitalization predictors of ICU readmission were performed. RESULTS: Of 512 subjects providing follow-up data, 58% were readmitted to the hospital (51% of these had multiple readmissions, averaging 3.9 readmissions per subject), 19% were readmitted to an ICU, and 12% required additional mechanical ventilation support. In univariate analyses, ICU readmission was more common among male subjects (OR 2.01; 95% CI 1.27-3.18), infants with grade 3-4 intracranial hemorrhage (OR 2.13; 95% CI 1.23-3.69), increasing duration of birth hospitalization (OR 1.01 per day; 95% CI 1.00-1.02), and prolonged oxygen therapy (OR 1.01 per day; 95% CI 1.00-1.01). In the first year after birth hospitalization, children readmitted to an ICU incurred greater health care costs (median $69,700 vs $30,200 for subjects admitted to the ward and $9600 for subjects never admitted). CONCLUSIONS: Small preterm infants who were mechanically ventilated at birth have substantial risk for readmission to an ICU and late mechanical ventilation, require extensive health care resources, and incur high treatment costs.

Trends in the epidemiology of pediatric severe sepsis*.

OBJECTIVES: In the past decade, guidelines have been developed for the early detection and management of severe sepsis in children and neonates. However, severe sepsis continues to be a significant U.S. healthcare problem, accounting for over 720,000 annual hospitalizations. Large-scale epidemiologic studies of severe sepsis continue to be limited, particularly in children. We present data from 1995, 2000, and 2005 in seven U.S. states, examining how case mix, outcome, and resource use for pediatric severe sepsis have changed over time. DESIGN: We constructed a database including all acute-care hospitalizations for children in the seven states. For each case, we extracted data on demographic characteristics; the principal diagnosis, up to six secondary diagnoses, and six procedures as classified by the International Classification of Diseases, 9th Revision, Clinical Modification codes; and in-hospital fatality. We identified patients with severe sepsis using International Classification of Diseases, 9th Revision, Clinical Modification codes for both infection and acute organ failure. SETTING: Retrospective observational cohort dataset from seven U.S. states from 1995, 2000, and 2005. SUBJECTS: Children in the U.S. 0-19 years old. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: In 2005, 17,542 children were hospitalized with severe sepsis in the seven states; there was an 81% increase in pediatric severe sepsis cases since 1995 and a 45% increase since 2000. This corresponded to an increase in prevalence from 0.56 to 0.89 cases per 1,000 pediatric population. Between 1995 and 2005, the prevalence of severe sepsis in newborns more than doubled, from 4.5 to 9.7 cases per 1,000 births. The most common infecting organisms in all 3 years were Staphylococcus species. From 1995 to 2005, the case-fatality rate decreased from 10.3% to 8.9%. Case fatality associated with Staphylococcus aureus increased, whereas fatality associated with Streptococcus pneumoniae decreased by 75%. Nationally, there were 75,255 pediatric hospitalizations in 2005 involving severe sepsis, with an associated cost of $4.8 billion. CONCLUSIONS: Between 1995 and 2005, the prevalence of severe sepsis in U.S. children steadily rose, due to a significant increase in the prevalence of severe sepsis in newborns.

Arsenic exposure and calpain-10 polymorphisms impair the function of pancreatic beta-cells in humans: a pilot study of risk factors for T2DM.

The incidence of type 2 diabetes mellitus (T2DM) is increasing worldwide and diverse environmental and genetic risk factors are well recognized. Single nucleotide polymorphisms (SNPs) in the calpain-10 gene (CAPN-10), which encodes a protein involved in the secretion and action of insulin, and chronic exposure to inorganic arsenic (iAs) through drinking water have been independently associated with an increase in the risk for T2DM. In the present work we evaluated if CAPN-10 SNPs and iAs exposure jointly contribute to the outcome of T2DM. Insulin secretion (beta-cell function) and insulin sensitivity were evaluated indirectly through validated indexes (HOMA2) in subjects with and without T2DM who have been exposed to a gradient of iAs in their drinking water in northern Mexico. The results were analyzed taking into account the presence of the risk factor SNPs SNP-43 and -44 in CAPN-10. Subjects with T2DM had significantly lower beta-cell function and insulin sensitivity. An inverse association was found between beta-cell function and iAs exposure, the association being more pronounced in subjects with T2DM. Subjects without T2DM who were carriers of the at-risk genotype SNP-43 or -44, also had significantly lower beta-cell function. The association of SNP-43 with beta-cell function was dependent on iAs exposure, age, gender and BMI, whereas the association with SNP-44 was independent of all of these factors. Chronic exposure to iAs seems to be a risk factor for T2DM in humans through the reduction of beta-cell function, with an enhanced effect seen in the presence of the at-risk genotype of SNP-43 in CAPN-10. Carriers of CAPN-10 SNP-44 have also shown reduced beta-cell function.

Metals in residential soils and cumulative risk assessment in Yaqui and Mayo agricultural valleys, northern Mexico.

This investigation examines the extent of soil metal pollution associated with the Green Revolution, relative to agricultural activities and associated risks to health in the most important agricultural region of Mexico. Metal contents in bulk soil samples are commonly used to assess contamination, and metal accumulations in soils are usually assumed to increase with decreasing particle size. This study profiled the spatial distribution of metals (Ni, Cr, Pb, Cu, Fe, Cd, V, Hg, Co, P, Se, and Mn) in bulk soil and fine-grained fractions (soil-derived dust) from 22 towns and cities. The contamination of soil was assessed through the use of a geoaccumulation index (Igeo) and pollution index (PI). The results of this study indicated that a number of towns and cities are moderately to highly polluted by soil containing Be, Co, Hg, P, S, V, Zn, Se, Cr, and Pb in both size fractions (coarse and fine). Hazard index in fine fraction (HI(children)=2.1) shows that risk assessment based on Co, Mn, V, and Ni spatially related to power plants, have the potential to pose health risks to local residents, especially children. This study shows that risk assessment based on metal content in bulk soil could be overestimated when compared to fine-grained fraction. Our results provide important information that could be valuable in establishing risk assessment associated with residential soils within agricultural areas, where children can ingest and inhale dust.

Indigenous American ancestry is associated with arsenic methylation efficiency in an admixed population of northwest Mexico.

Many studies provide evidence relating lower human arsenic (As) methylation efficiency, represented by high percent urinary monomethylarsonic acid (MMA(V)), with several As-induced diseases, possibly due to the fact that MMA(V) serves as a proxy for MMA(III), the most toxic As metabolite. Some epidemiological studies suggested that indigenous Americans (AME) methylate As more efficiently; however, data supporting this have been equivocal. The aim of this study was to characterize the association between AME ancestry and As methylation efficiency using a panel of ancestry informative genetic markers to determine individual ancestry proportions in an admixed population (composed of two or more isolated ancestral populations) of 746 individuals environmentally exposed to As in northwest Mexico. Total urinary As (TAs) mean and range were 170.4 and 2.3-1053.5 µg/L, while percent AME (%AME) mean and range were 72.4 and 23-100. Adjusted (gender, age, AS3MT 7388/M287T haplotypes, body mass index [BMI], and TAs) multiple regression model showed that higher AME ancestry is significantly associated with lower percentage of urinary As excreted as MMA(V) (%uMMA) in this population (p < .01). Data also demonstrated a significant interaction between BMI and gender, indicating negative association between BMI and %uMMA, stronger in women than men (p < .01). Moreover, age and the AS3MT variants 7388 (intronic) and M287T (nonsynonymous) were also significantly associated with As methylation efficiency (p < .01). This study highlights the importance of BMI and indigenous American ancestry in some of the observed variability in As methylation efficiency, underscoring the need to be considered in epidemiology studies, particularly those carried out in admixed populations.

Association between body mass index and arsenic methylation efficiency in adult women from southwest U.S. and northwest Mexico.

Human arsenic methylation efficiency has been consistently associated with arsenic-induced disease risk. Interindividual variation in arsenic methylation profiles is commonly observed in exposed populations, and great effort has been put into the study of potential determinants of this variability. Among the factors that have been evaluated, body mass index (BMI) has not been consistently associated with arsenic methylation efficiency; however, an underrepresentation of the upper BMI distribution was commonly observed in these studies. This study investigated potential factors contributing to variations in the metabolism of arsenic, with specific interest in the effect of BMI where more than half of the population was overweight or obese. We studied 624 adult women exposed to arsenic in drinking water from three independent populations. Multivariate regression models showed that higher BMI, arsenic (+3 oxidation state) methyltransferase (AS3MT) genetic variant 7388, and higher total urinary arsenic were significantly associated with low percentage of urinary arsenic excreted as monomethylarsonic acid (%uMMA) or high ratio between urinary dimethylarsinic acid and uMMA (uDMA/uMMA), while AS3MT genetic variant M287T was associated with high %uMMA and low uDMA/uMMA. The association between BMI and arsenic methylation efficiency was also evident in each of the three populations when studied separately. This strong association observed between high BMI and low %uMMA and high uDMA/uMMA underscores the importance of BMI as a potential arsenic-associated disease risk factor, and should be carefully considered in future studies associating human arsenic metabolism and toxicity.

Aquatic microbial habitats within a neotropical rainforest: bromeliads and pH-associated trends in bacterial diversity and composition.

Tank-forming bromeliads, suspended in the rainforest canopy, possess foliage arranged in compact rosettes capable of long-term retention of rainwater. This large and unique aquatic habitat is inhabited by microorganisms involved in the important decomposition of impounded material. Moreover, these communities are likely influenced by environmental factors such as pH, oxygen, and light. Bacterial community composition and diversity was determined for the tanks of several bromeliad species (Aechmea and Werauhia) from northern Costa Rica, which span a range of parameters, including tank morphology and pH. These were compared with a nearby forest soil sample, an artificial tank (amber bottle), and a commercially available species (Aechmea). Bacterial community diversity, as measured by 16S rRNA analysis and tRFLP, showed a significant positive correlation with tank pH. A majority of 16S rRNA bacterial phylotypes found in association with acidic bromeliad tanks of pH < 5.1 were affiliated with the Alphaproteobacteria, Acidobacteria, Planctomycetes, and Bacteroidetes, and were similar to those found in acidic peat bogs, yet distinct from the underlying soil community. In contrast, bromeliads with tank pH > 5.3, including the commercial bromeliad with the highest pH (6.7), were dominated by Betaproteobacteria, Firmicutes, and Bacteroidetes. To empirically determine the effect of pH on bacterial community, the tank pH of a specimen of Aechmea was depressed, in the field, from 6.5 to 4.5, for 62 days. The resulting community changed predictably with decreased abundance of Betaproteobacteria and Firmicutes and a concomitant increase in Alphaproteobacteria and Acidobacteria. Collectively, these results suggest that bromeliad tanks provide important habitats for a diverse microbial community, distinct from the surrounding environment, which are influenced greatly by acid-base conditions. Additionally, total organic carbon (∼46%) and nitrogen (∼2%) of bromeliad-impounded sediment was elevated relative to soil and gene surveys confirmed the presence of both chitinases and nitrogenases, suggesting that bromeliad tanks may provide important habitats for microbes involved in the biological cycling of carbon and nitrogen in tropical forests.

Genetic association between intronic variants in AS3MT and arsenic methylation efficiency is focused on a large linkage disequilibrium cluster in chromosome 10.

Differences in arsenic metabolism are known to play a role in individual variability in arsenic-induced disease susceptibility. Genetic variants in genes relevant to arsenic metabolism are considered to be partially responsible for the variation in arsenic metabolism. Specifically, variants in arsenic (3+ oxidation state) methyltransferase (AS3MT), the key gene in the metabolism of arsenic, have been associated with increased arsenic methylation efficiency. Of particular interest is the fact that different studies have reported that several of the AS3MT single nucleotide polymorphisms (SNPs) are in strong linkage-disequilibrium (LD), which also extends to a nearby gene, CYP17A1. In an effort to characterize the extent of the region in LD, we genotyped 46 SNPs in a 347,000 base region of chromosome 10 that included AS3MT in arsenic-exposed subjects from Mexico. Pairwise LD analysis showed strong LD for these polymorphisms, represented by a mean r(2) of 0.82, spanning a region that includes five genes. Genetic association analysis with arsenic metabolism confirmed the previously observed association between AS3MT variants, including this large cluster of linked polymorphisms, and arsenic methylation efficiency. The existence of a large genomic region sharing strong LD with polymorphisms associated with arsenic metabolism presents a predicament because the observed phenotype cannot be unequivocally assigned to a single SNP or even a single gene. The results reported here should be carefully considered for future genomic association studies involving AS3MT and arsenic metabolism.

Estudo nosológico das dermatoses diagnosticadas no hospital da Universidade Federal de Juiz de Fora / Dermatoses diagnosed at the university hospital of the Federal University of Juiz de Fora

O censo dermatológico das diversas regiões brasileiras apresenta inegável importância para a Sociedade Brasileira de Dermatologia no intuito de se priorizar também seu papel social, assim como sua função no desenvolvimento da política de saúde do país. O objetivo do trabalho é o levantamento nosológico das dermatoses mais freqüentes de uma ampla região que abrange parte do Estado de Minas Gerais e do Estado do Rio de Janeiro, com a finalidade de fornecer dados para posteriores trabalhos e iniciativas afins específicas. Foram avaliados 14.784 prontuários dermatológicos referentes ao período de 02 de fevereiro de 2003 a 02 de fevereiro de 2006. Deste total, ao excluírem-se os retornos, obtiveram-se um total de 9.031 pacientes atendidos, valor referente ao número de patologias diagnosticadas e tratadas no Serviço de Dermatologia do Hospital Universitário da Universidade Federal de Juiz de Fora. Os diagnósticos foram subdivididos de forma compacta e didática. Os resultados mais frequentes foram Tumores Cutâneos com 19,9% do total; Infecções Cutâneas com 19,89%; Eczemas com 13,56% e Afecções dos Anexos com 10,56%. Quanto às infecções, estas representam um grande percentual dos casos analisados, o que se deve provavelmente ao baixo nível socioeconômico dos pacientes em estudo. O presente Censo Dermatológico fornece subsídios para as diversas instâncias governamentais no planejamento das políticas de saúde na área da dermatologia, assim como para os programas de formação em dermatologia.

A dermatological survey of the different Brazilian regions provides scope for the Brazilian Dermatology Society to both play its social role and influence the national health policies. The objective of this study is the data-gathering nosological survey of the most frequently diagnosed dermatological conditions in a region comprising part of the states of Minas Gerais and Rio de Janeiro, Brazil. 14.784 medical records of Dermatology from the period February 2, 2003 to February 2, 2006 were assessed.After exclusion of follow-up visits, 9.031 patients were seen at the Dermatology Clinic. Diagnoses were clustered in a compact and didatic way. The results were that 19.9% of the patients were diagnosed with skin tumors, 19.89% with skin infections, 13.56% with eczema, and 10.56% with infection of the skin annexes. The low socioeconomic status of the patients is likely to account for the high percentage of skin infections. This dermatological census informs different government levels about priorities for health policies and professional education.

The small-scale urban reservoir fisheries of Lago Paranoá, Brasília, DF, Brazil.

In many cases in large urban centers, which have appropriate waterbodies, small-scale fisheries are the only source of cheap protein for the poor. In Lago Paranoá, located in Brasília, the capital city of Brazil, fishing was studied by conducting interviews with 53 fishers filling in logbooks from March, 1999 to March, 2000 in three fishing communities. The fishers come from the poorest towns around Brasília, known as satellite-towns. They have been living there on average for 21.7 years (s = 9.6 years), their families have 4.9 members (s = 3.6) on average and 44.2% do not have a basic education. However, such characteristics are similar to the socioeconomic indices of the metropolis where they live. In spite of being illegal between 1966 and 2000, fishing generated an average monthly income of U 239.00 dollars (s = U 171.77 dollars). The Nile Tilapia Oreocrhromis niloticus is the main captured species (85% of a total number of landings in weight of 62.5 t.). Fishing is carried out in rowing boats, individually or in pairs. The fishing equipment used are gillnets and castnets. Gillnets were used actively, whereby the surface of the water is beaten with a stick to drive Tilapias towards nets as they have the ability to swim backwards. This fishing strategy was used in 64.7% of the fisheries, followed by castnets (31.1%) and by gillnets which were used less (4.2%). The fish is sold directly in the streets and fairs of the satellite-towns to middlemen or to bar owners. Three communities have different strategies in terms of fishing equipments, fishing spots and commercialization. Consequently, there are statistically significant differences in relation to the monthly income for each one of these communities.

Developmental and genetic modulation of arsenic biotransformation: a gene by environment interaction?

The complexity of arsenic toxicology has confounded the identification of specific pathways of disease causation. One focal point of arsenic research is aimed at fully characterizing arsenic biotransformation in humans, a process that appears to be quite variable, producing a mixture of several arsenic species with greatly differing toxic potencies. In an effort to characterize genetic determinants of variability in arsenic biotransformation, a genetic association study of 135 subjects in western Sonora, Mexico was performed by testing 23 polymorphic sites in three arsenic biotransformation candidate genes. One gene, arsenic 3 methyltransferase (AS3MT), was strongly associated with the ratio of urinary dimethylarsinic acid to monomethylarsonic acid (D/M) in children (7-11 years) but not in adults (18-79 years). Subsequent analyses revealed that the high D/M values associated with variant AS3MT alleles were primarily due to lower levels of monomethylarsonic acid as percent of total urinary arsenic (%MMA5). In light of several reports of arsenic-induced disease being associated with relatively high %MMA5 levels, these findings raise the possibility that variant AS3MT individuals may suffer less risk from arsenic exposure than non-variant individuals. These analyses also provide evidence that, in this population, regardless of AS3MT variant status, children tend to have lower %MMA5 values than adults, suggesting that the global developmental regulation of arsenic biotransformation may interact with genetic variants in metabolic genes to result in novel genetic effects such as those in this report.

The small-scale urban reservoir fisheries of Lago Paranoá, Brasília, DF, Brazil

In many cases in large urban centers, which have appropriate waterbodies, small-scale fisheries are the only source of cheap protein for the poor. In Lago Paranoá, located in Brasília, the capital city of Brazil, fishing was studied by conducting interviews with 53 fishers filling in logbooks from March, 1999 to March, 2000 in three fishing communities. The fishers come from the poorest towns around Brasília, known as satellite-towns. They have been living there on average for 21.7 years (s = 9.6 years), their families have 4.9 members (s = 3.6) on average and 44.2 percent do not have a basic education. However, such characteristics are similar to the socioeconomic indices of the metropolis where they live. In spite of being illegal between 1966 and 2000, fishing generated an average monthly income of U$ 239.00 (s = U$ 171.77). The Nile Tilapia Oreocrhromis niloticus is the main captured species (85 percent of a total number of landings in weight of 62.5 t.). Fishing is carried out in rowing boats, individually or in pairs. The fishing equipment used are gillnets and castnets. Gillnets were used actively, whereby the surface of the water is beaten with a stick to drive Tilapias towards nets as they have the ability to swim backwards. This fishing strategy was used in 64.7 percent of the fisheries, followed by castnets (31.1 percent) and by gillnets which were used less (4.2 percent). The fish is sold directly in the streets and fairs of the satellite-towns to middlemen or to bar owners. Three communities have different strategies in terms of fishing equipments, fishing spots and commercialization. Consequently, there are statistically significant differences in relation to the monthly income for each one of these communities.

Em muitos centros urbanos, com corpos d'água apropriados, as pescarias de pequena escala são a única fonte de proteína barata para os pobres. No Lago Paranoá, localizado em Brasília, a atividade pesqueira foi estudada através de entrevistas com 53 pescadores que vivem em cidades satélites, de Março/1999 a Março/2000, em três comunidades pesqueiras. Nesse período os pescadores viviam nas cidades satélites em média há 21,7 anos (s = 9,6 anos), com famílias de 4,9 membros (s = 3,6) e 44,2 por cento deles não possuíam instrução mínima. Entretanto, suas condições são semelhantes aquelas apontadas pelos indicadores socioeconômicos das áreas onde residem. A pesca, embora clandestina de 1966 a 2000, gerou um rendimento médio de U$ 239,00 (s = U$ 171,77). A tilápia do Nilo Oreochromis niloticus foi a principal espécie capturada (85 por cento de um rendimento total em peso de 62,5 t). As pescarias foram realizadas em canoas a remo, individualmente ou em duplas. As artes empregadas foram a malhadeira e a tarrafa. A malhadeira foi empregada de modo ativo sob a forma de batida, onde se bate na água com um bastão para afugentar as tilápias em direção às redes. Essa estratégia foi empregada em 64,7 por cento das pescarias, seguida pela tarrafa (31,1 por cento) e pela malhadeira empregada passivamente (4,2 por cento). O pescado foi vendido diretamente nas ruas e em feiras das cidades-satélite, por atravessadores ou donos de bar. As três comunidades de pescadores apresentam estratégias diferentes para pescar e comercializar o pescado. Assim há diferenças significativas em relação à essa fonte de renda, entre as comunidades.

The small-scale urban reservoir fisheries of Lago Paranoá, Brasília, DF, Brazil

In many cases in large urban centers, which have appropriate waterbodies, small-scale fisheries are the only source of cheap protein for the poor. In Lago Paranoá, located in Brasília, the capital city of Brazil, fishing was studied by conducting interviews with 53 fishers filling in logbooks from March, 1999 to March, 2000 in three fishing communities. The fishers come from the poorest towns around Brasília, known as satellite-towns. They have been living there on average for 21.7 years (s = 9.6 years), their families have 4.9 members (s = 3.6) on average and 44.2% do not have a basic education. However, such characteristics are similar to the socioeconomic indices of the metropolis where they live. In spite of being illegal between 1966 and 2000, fishing generated an average monthly income of U$ 239.00 (s = U$ 171.77). The Nile Tilapia Oreocrhromis niloticus is the main captured species (85% of a total number of landings in weight of 62.5 t.). Fishing is carried out in rowing boats, individually or in pairs. The fishing equipment used are gillnets and castnets. Gillnets were used actively, whereby the surface of the water is beaten with a stick to drive Tilapias towards nets as they have the ability to swim backwards. This fishing strategy was used in 64.7% of the fisheries, followed by castnets (31.1%) and by gillnets which were used less (4.2%). The fish is sold directly in the streets and fairs of the satellite-towns to middlemen or to bar owners. Three communities have different strategies in terms of fishing equipments, fishing spots and commercialization. Consequently, there are statistically significant differences in relation to the monthly income for each one of these communities.

Em muitos centros urbanos, com corpos d'água apropriados, as pescarias de pequena escala são a única fonte de proteína barata para os pobres. No Lago Paranoá, localizado em Brasília, a atividade pesqueira foi estudada através de entrevistas com 53 pescadores que vivem em cidades satélites, de Março/1999 a Março/2000, em três comunidades pesqueiras. Nesse período os pescadores viviam nas cidades satélites em média há 21,7 anos (s = 9,6 anos), com famílias de 4,9 membros (s = 3,6) e 44,2% deles não possuíam instrução mínima. Entretanto, suas condições são semelhantes aquelas apontadas pelos indicadores socioeconômicos das áreas onde residem. A pesca, embora clandestina de 1966 a 2000, gerou um rendimento médio de U$ 239,00 (s = U$ 171,77). A tilápia do Nilo Oreochromis niloticus foi a principal espécie capturada (85% de um rendimento total em peso de 62,5 t). As pescarias foram realizadas em canoas a remo, individualmente ou em duplas. As artes empregadas foram a malhadeira e a tarrafa. A malhadeira foi empregada de modo ativo sob a forma de batida, onde se bate na água com um bastão para afugentar as tilápias em direção às redes. Essa estratégia foi empregada em 64,7% das pescarias, seguida pela tarrafa (31,1%) e pela malhadeira empregada passivamente (4,2%). O pescado foi vendido diretamente nas ruas e em feiras das cidades-satélite, por atravessadores ou donos de bar. As três comunidades de pescadores apresentam estratégias diferentes para pescar e comercializar o pescado. Assim há diferenças significativas em relação à essa fonte de renda, entre as comunidades.

Income evaluation of small - scale fishers in two Brazilian urban reservoirs: Represa Billings (SP) and Lago Paranoá (DF).

The income of small-scale fisheries of two urban reservoirs in Brazil: Represa Billings (127 km2) located in the metropolitan region of São Paulo, the capital city of the state of São Paulo and Lago Paranoá (38 km2) located in Brasília (DF), the capital city of Brazil were calculated and compared. Both fisheries are mainly based on the alien Nile tilapia Oreochromis niloticus (more than 80% of the total catch). Although these reservoirs are nearly 900 km apart, their native fish fauna belong to the Upper Paraná Province. The Represa Billings fishers have, on average, a daily profit of 15.8 R dollars (8.4 U dollars mostly employing gill nets) and Lago Paranoá fishers 46.6 R dollars (24.9 U dollars, mostly employing cast nets), which is a statistically significant difference (P < 0.001). The profit of the fisheries is explained by the factor "reservoir" and covariate "days of fishing". Due to the increasing violence in the metropolitan region of São Paulo, the Represa Billings fishery is vanishing.

Income evaluation of small - scale fishers in two brazilian urban reservoirs: Represa Billings (SP) and Lago Paranoá (DF) / Avaliação da renda dos pescadores de pequena escala em dois reservatórios urbanos brasileiros: Represa Billings (SP) e Lago Paranoá (DF)

The income of small-scale fisheries of two urban reservoirs in Brazil: Represa Billings (127 km²) located in the metropolitan region of São Paulo, the capital city of the state of São Paulo and Lago Paranoá (38 km²) located in Brasília (DF), the capital city of Brazil were calculated and compared. Both fisheries are mainly based on the alien Nile tilapia Oreochromis niloticus (more than 80 percent of the total catch). Although these reservoirs are nearly 900 km apart, their native fish fauna belong to the Upper Paraná Province. The Represa Billings fishers have, on average, a daily profit of R$ 15.8 (U$ 8.4 mostly employing gill nets) and Lago Paranoá fishers R$ 46.6 (U$ 24.9, mostly employing cast nets), which is a statistically significant difference (P < 0.001). The profit of the fisheries is explained by the factor "reservoir" and covariate "days of fishing". Due to the increasing violence in the metropolitan region of São Paulo, the Represa Billings fishery is vanishing.

Neste artigo, foi calculada e comparada a renda média de pescadores de pequena escala, que operam em dois reservatórios urbanos no Brasil: na Represa Billings (127 km²), localizada na região metropolitana da cidade de São Paulo, e no Lago Paranoá (38 km²), localizado em Brasília (DF). Ambas as pescarias são baseadas em espécies exóticas, principalmente a Tilápia do Nilo, Oreochromis niloticus (mais de 80 por cento das capturas). Os pescadores da Represa Billings têm um ganho médio diário de R$ 17,75 (U$ 8,4), empregando principalmente a rede-de-espera. Os pescadores do Lago Paranoá têm um ganho médio diário de R$ 46,58 (U$ 24,9), empregando principalmente a tarrafa. A renda dos pescadores de Brasília é estatisticamente superior à dos pescadores de São Paulo (P < 0.01). O lucro dessas pescarias é explicado pela natureza do reservatório (Paranoá ou Billings) e pelos dias de pesca. Devido ao aumento da violência na região metropolitana de São Paulo, as pescarias na Represa Billings estão desaparecendo.