Efecto de variables abióticas en la fauna hiporreica del río Dagua, Colombia / Effect of abiotic variables on the hyporheic fauna of Dagua River, Colombia

Introducción: La fauna de sedimentos del subsuelo, donde se da el intercambio entre aguas subterráneas y superficiales, llamada "fauna hiporreica", cumple funciones ecológicas importantes en los ríos; sin embargo, no ha sido estudiada suficientemente en Colombia. Objetivo: Identificar las relaciones entre los invertebrados hiporreicos y variables fisicoquímicas en el río Dagua, Colombia. Métodos: En tres giras a campo (entre octubre 2017 y diciembre 2018) en cinco estaciones de muestreo a lo largo de la cuenca del río, realizamos perforaciones implementando el método de Karaman-Chappuis (sedimento, agua e invertebrados), y registramos la granulometría y materia orgánica en los sedimentos; además, medimos nutrientes, iones y metales en el agua. Resultados: Las estaciones en la zona de cabecera tuvieron sustratos con sedimentos gruesos (grava y piedra), mayores niveles de oxígeno, y menor temperatura del agua. La riqueza y diversidad de especies fueron mayores en estaciones en la zona cabecera, donde predominaron Copepoda e Insecta, mientras que en sitios de cuenca baja predominaron Arachnida (Hydrachnidiae), Clitellata (Oligochaeta) y Nematoda. Conclusiones: La distribución y abundancia de la fauna hiporreica fueron principalmente influenciadas por cambios en la granulometría del sustrato hiporreico y sus contenidos de materia orgánica.

Introduction: The fauna from the subsurface sediments where groundwaters and surface waters are exchanged, called "hyporheic fauna", fulfills important ecological functions in rivers, but has not been sufficiently studied in Colombia. Objective: To identify relationships between hyporheic invertebrates and physicochemical variables in the Dagua River, Colombia. Methods: In three field trips (between October 2017 and December 2018) to five sites along the river basin, we drilled with the Karaman-Chappuis method (sediment, water, and invertebrates), and recorded granulometry and organic matter in sediments; and nutrients, ions, and metals in water. Results: The headwater stations had substrates with coarser sediments (gravel and stone), higher oxygen levels, and lower water temperature. Both richness and species diversity were higher at the headwater stations, dominated by Copepoda and Insecta, while the lower basin was dominated by Arachnida (Hydrachnidiae), Clitellata (Oligochaeta), and Nematoda. Conclusions: The distribution and abundance of the hyporheic fauna were principally influenced by changes in the granulometry of the hyporheic substrate and its content of organic matter.

Protocol for Membracidae inventory (Hemiptera, Auchenorrhyncha, Membracoidea): what are the ideal collection methods for the Atlantic Forest? / Protocolo para inventário de Membracidae (Hemiptera, Auchenorrhyncha, Membracoidea): quais os métodos de coleta ideais para Floresta Atlântica?

Abstract: Membracidae are phytophagous insects that present different types of behavior, requiring a specific protocol for fast and efficient collection. This article evaluates the best methods for sampling these insects in Atlantic Forest areas. The protocol was applied in four areas of the Atlantic Forest in Paraíba state, Brazil, and involved a team of four people at a cost of US$180 per area. Each area contained 100 sampling units subdivided into 30 yellow sticky cards in the canopy and 30 yellow sticky cards in the lower stratum, 30 active collections and 10 light traps. In total, 2,678 specimens belonging to 91 species were sampled. The highest abundance and richness values were obtained using active collection (N = 1,517; S = 42) and cards in the canopy (N = 345; S = 53). All methods exhibited high complementarity, with more than half of the species (S = 50; 54.35%) recorded exclusively by only one of the methods applied. Similarity analysis revealed that active collection differs significantly from all other methods (R = 0.10, p = 0.0001) and that the sticky cards in the canopy differ from the collection in the lower stratum (p = 0.0001), whereas the other method pairs did not exhibit significant differences. In all areas, the active collection, the sticky cards in the canopy and the lower stratum had the best sample sufficiency, with at least 60% of the estimated values. To inventory Membracidae specimens in areas of the Atlantic Forest, a protocol that combines different collection methods is required, which in principle requires more time and expense. However, it is worth noting that it is possible to adjust this protocol according to the researcher's need. For a faster survey that includes the largest number of species, we suggest a combination of active collection and a light trap.

Resumo: Membracídeos são insetos fitófagos que apresentam diferentes tipos de comportamento, o que requer um protocolo específico para uma coleta rápida e eficiente. Este artigo avalia quais os melhores métodos para amostragem desses insetos em áreas de Floresta Atlântica. O protocolo foi aplicado em quatro áreas de Floresta Atlântica na Paraíba e envolveu uma equipe de quatro pessoas, ao custo de U$180 por área. Contém 100 unidades amostrais subdividas em 30 cartões adesivos amarelos no dossel, e 30 no estrato inferior, 30 coletas ativas e 10 armadilhas luminosas. No total foram amostrados 2.678 espécimes pertencentes a 91 espécies. As maiores abundâncias e valores de riqueza foram obtidos usando a coleta ativa (N = 1.517; S = 42) e os cartões do dossel (N = 345; S = 53). Todos os métodos apresentaram alta complementaridade, com mais da metade das espécies (S = 50; 54,35%) registradas exclusivamente por apenas um dos métodos aplicados. A análise de similaridade mostrou que a coleta ativa difere significativamente de todos os outros métodos (R = 0,10; p = 0,0001), e que os cartões adesivos no dossel diferem da coleta no estrato inferior (p = 0,0001), enquanto os outros pares de métodos não apresentaram diferenças significativas. Em todas as áreas, a coleta ativa, os cartões adesivos no dossel e no estrato inferior, respectivamente, foram os que apresentaram melhor suficiência amostral, com valores de no mínimo 60% do estimado. Foi demonstrado que, para inventariar membracídeos em áreas de Floresta Atlântica, é necessário um protocolo que combine diferentes métodos de coleta, o que à priori, demanda mais tempo e custo. Contudo, vale ressaltar que é possível ajustar este protocolo de acordo com a necessidade do pesquisador. Indicamos que para um levantamento mais rápido e que contemple o maior número de espécies, o ideal é utilizar uma combinação de coleta ativa e armadilha luminosa.

Reflexión acerca de la regresión logística y las decisiones clínicas / Reflection on logistic regression and clinical decisions

Introducción. La aplicación del estudio de riesgos mediante la regresión logística múltiple implica necesariamente realizar tales estimaciones con la necesaria información al clínico acerca de todas las limitaciones que dicho trabajo tiene. Problema. Es posible que los trabajos que aplican la regresión logística múltiple no incluyan el uso de las pruebas de Bondad de Ajuste o del Coeficiente de Determinación o ambas. Desarrollo: pueden existir altos valores de riesgo relativo u odds ratio junto a modelos no ajustados o bajos valores del coeficiente de determinación o ambos al mismo tiempo. Como consecuencia, si el profesional clínico no posee esta información, en relación a una entidad dada, no puede saber si las estimaciones de altos valores de riesgo tienen o no importancia clínica y, por tanto, la ausencia de reportes de estos estimadores podría implicar una intervención terapéutica cuyos resultados podrían no ser los esperados. Conclusión: Los investigadores que aplican el modelo de la regresión logística deben obligatoriamente informar de los resultados de los estimadores que le dan consistencia a dicho modelo.

Introduction. The application of risk study through multiple logistic regression necessarily involves making such estimates with the necessary information to the clinician about all the limitations that such work has. Problem. It is possible that works that apply multiple logistic regression do not include the use of the tests of Goodness of Adjustment or the Coefficient of Determination or both. Development: there may be high values of relative risk or odds ratio together with unadjusted models or low values of the coefficient of determination or both at the same time. Therefore, if the clinician does not have this information, in relation to a given entity, it cannot know whether the estimates of elevated risk values are of clinical importance or not and, therefore, the absence of reports of these estimators could imply a therapeutic intervention whose results may not be as expected. Conclusion: Researchers applying the logistic regression model must necessarily report the results of the estimators that give consistency to said model.

Os fatores clássicos e a falha dos implantes dentários: qual o significado estatístico para a prática clínica? / On classic factors and dental implant failures: what is the statistical significance for the daily practice?

Objetivo: identificar quais dos fatores clássicos (material, desenho, superfície do implante, hospedeiro, técnica cirúrgica, protocolo de carga) possuem significado estatístico no prognóstico dos implantes. Material e métodos: uma busca eletrônica foi realizada no sistema PubMed/Medline até junho de 2015 com palavras-chave representativas dos estimadores, combinadas por operadores booleanos. Foram incluídos estudos clínicos contendo amostras com pelo menos 50 pacientes e 100 implantes, mínimo de um ano de acompanhamento, apresentando os estimadores obtidos através de modelo de Cox (Hazard ratio) ou regressão logística (Odds ratio, Risk ratio). O desfecho primário foi a falha do implante. Resultados: das 871 referências iniciais, foram selecionadas 20 após leitura integral, com mais de dez mil pacientes e mais de 30 mil implantes. Nos artigos com modelo de Cox, foram identificados o tabagismo (valores entre 1,04 e 3,9), o diâmetro (valores HR entre 1,72 e 6,35) e o comprimento (valores HR entre 0,8 e 2,7) do implante, as técnicas cirúrgicas específicas para melhorar o leito receptor (HR entre 2 e 5), os protocolos de carga (HR entre 0,1 e 9,7), o operador (HR=4,2; um estudo) e a maxila (HR=10; um estudo). Nos artigos com regressão logística, foram identificados os maiores valores de risco para implantes de largo diâmetro (OR=4,25; um estudo), implantes colocados na região posterior da maxila (OR=6,83; um estudo) e ausência de gengiva queratinizada (OR=4,7; um estudo). Conclusão: os fatores têm frequência variada, dependem da homogeneidade das amostras e nem sempre demonstram significado estatístico. Possíveis explicações podem ser atribuídas para as falhas. Mesmo assim, a documentação clínica detalhada continua fundamental para anteciparmos problemas em áreas estratégicas.

Objective: to identify which of the classic factors (implant material, design, surface; host, surgical technique, loading protocol) can have a statistical significance on dental implant prognosis. Material and methods: an electronic search at the PubMed/Medline was made until June 2015 with representative keywords combined by Boolean operators. Clinical studies with at least 50 patients and 100 implants, 1 year of follow-up, having statistical estimators such as Cox model (Hazard ratio) or logistic regression (Odds ratio, Risk ratio) analyses were included. The primary outcome was implant failure. Results: of the 871 retrieved records, 20 references were finally selected, summing up more than 10 thousand patients and 30 thousand dental implants. For articles using the Cox´s model, tobacco (HR values between 1.04 to 3.9), diameter (HR between 1.72 to 6.35), and implant length (HR between 0.8 to 2.7); specific surgical techniques to improve the recipient bed (HR between 2 and 5), loading protocols (HR from 0.1 to 9.7), the operator (HR=4.2, one study), and the maxillary arch (HR=10, 1 study) were identified. For articles containing logistic regression, the highest chance values were identified for large diameter implants (OR=4.25, one study), implants at the posterior maxillary region (OR=6.83, one study), and the lack of keratinized gingiva (OR=4.7, one study). Conclusion: these factors have a varied frequency, depend on sample´s homogeneity, and not always provide statistical meaning. Possible explanations can be attributed to failures. Even thus, a detailed clinical documentation remains mandatory to anticipate problems in strategic areas.

A structured inventory of spiders (Arachnida, Araneae) in natural and artificial forest gaps at Porto Urucu, Western Brazilian Amazonia / Inventário estruturado de aranhas (Arachnida, Araneae) em clareiras naturais e artificiais em Porto Urucu, Amazônia Ocidental Brasileira

A preliminary survey of the spider fauna in natural and artificial forest gap formations at "Porto Urucu", a petroleum/natural gas production facility in the Urucu river basin, Coari, Amazonas, Brazil is presented. Sampling was conducted both occasionally and using a protocol composed of a suite of techniques: beating trays (32 samples), nocturnal manual samplings (48), sweeping nets (16), Winkler extractors (24), and pitfall traps (120). A total of 4201 spiders, belonging to 43 families and 393 morphospecies, were collected during the dry season, in July, 2003. Excluding the occasional samples, the observed richness was 357 species. In a performance test of seven species richness estimators, the Incidence Based Coverage Estimator (ICE) was the best fit estimator, with 639 estimated species. To evaluate differences in species richness associated with natural and artificial gaps, samples from between the center of the gaps up to 300 meters inside the adjacent forest matrix were compared through the inspection of the confidence intervals of individual-based rarefaction curves for each treatment. The observed species richness was significantly higher in natural gaps combined with adjacent forest than in the artificial gaps combined with adjacent forest. Moreover, a community similarity analysis between the fauna collected under both treatments demonstrated that there were considerable differences in species composition. The significantly higher abundance of Lycosidae in artificial gap forest is explained by the presence of herbaceous vegetation in the gaps themselves. Ctenidae was significantly more abundant in the natural gap forest, probable due to the increase of shelter availability provided by the fallen trees in the gaps themselves. Both families are identified as potential indicators of environmental change related to the establishment or recovery of artificial gaps in the study area.

Apresenta-se um inventário preliminar da fauna de aranhas em clareiras naturais e artificiais em "Porto Urucu", uma instalação produtora de petróleo e gás natural na bacia do Rio Urucu, Coari, Amazonas, Brasil. As amostras foram realizadas de modo ocasional e com um protocolo estruturado composto por um conjunto de técnicas de amostragem: guarda-chuvas entomológicos (32 amostras), amostras manuais noturnas (48), rede de varredura (16), extratores de Winkler (24) e armadilhas de queda (120). Um total de 4201 aranhas pertencentes a 43 famílias e 393 morfoespécies foi coletado durante a estação seca em julho de 2003. Excluindo as amostras ocasionais, a riqueza observada foi de 357 espécies. No teste de desempenho de sete estimadores, ICE (Incidence Based Coverage Estimator) gerou o melhor resultado, com 639 espécies estimadas. Para avaliar diferenças na riqueza de espécies associadas a clareiras naturais e artificiais, conjuntos de amostras do centro da clareira a até 300 m adentro da floresta adjacente foram comparados através da inspeção dos intervalos de confiança de curvas de rarefação baseadas no número de indivíduos de cada tratamento. A riqueza observada foi significantemente maior nas clareiras naturais combinadas com as florestas adjacentes do que nas clareiras artificiais combinadas com as matas do entorno. Além disso, uma análise de similaridade entre as faunas coletadas em ambos os tratamentos mostrou que existe diferenças consideráveis na composição de espécies. A abundância significativamente mais alta de Lycosidae nas florestas de clareiras artificiais é explicada pela presença de vegetação herbácea nas clareiras propriamente ditas. Ctenidae foi significantemente mais abundante nas florestas de clareiras naturais, provavelmente devido ao aumento da disponibilidade de abrigos causado pela queda de árvores nas clareiras propriamente ditas. Ambas estas famílias são identificadas como potenciais indicadores de mudanças ambientais relacionadas com o estabelecimento ou recuperação de clareiras artificiais na área de estudo.

Notes on necrophagous flies (Diptera: Calyptratae) associated to fish carrion in Colombian Amazon / Notas sobre moscas necrófagas (Diptera: Caliptratae) associadas a carcaças de peixe na Amazônia Colombiana

In recent years, there has been an increasing number of studies on carrion fly communities due to their medical importance and as a consequence of the large number of studies on forensic entomology. Surprisingly few studies have adressed with the asynantropic flies of the Amazon, and none were done in Colombia. A faunistic study of asynantropic flies of the families Calliphoridae, Sarcophagidae, Muscidae and Fannidae in three different landscapes of the Colombian Amazon is presented, trapping effectiveness is assessed, and the first record of Mesembrinella batesi (Aldrich, 1922) and Fannia femoralis (Stein, 1897) from Colombia is reported.

Apesar de existir uma quantidade considerável de estudos sobre dípteros decompositores devido a sua importância medica e ao avanço da entomologia forense, poucos dizem respeito as moscas asinantrópicas na Amazônia e nada foi feito na Colômbia. No presente trabalho é feito um estudo faunístico sobre moscas, principalmente das famílias Calliphoridae, Sarcophagidae, Muscidae e Fanniidae em três diferentes paisagens da Amazônia Colombiana, além do primeiro registro das espécies Mesembrinella batesi (Aldrich, 1922) e Fannia femoralis (Stein, 1897) para Colômbia e avaliação da amostragem utilizada.

Estimation procedures affect the center of pressure frequency analysis

Even though frequency analysis of body sway is widely applied in clinical studies, the lack of standardized procedures concerning power spectrum estimation may provide unreliable descriptors. Stabilometric tests were applied to 35 subjects (20-51 years, 54-95 kg, 1.6-1.9 m) and the power spectral density function was estimated for the anterior-posterior center of pressure time series. The median frequency was compared between power spectra estimated according to signal partitioning, sampling rate, test duration, and detrending methods. The median frequency reliability for different test durations was assessed using the intraclass correlation coefficient. When increasing number of segments, shortening test duration or applying linear detrending, the median frequency values increased significantly up to 137%. Even the shortest test duration provided reliable estimates as observed with the intraclass coefficient (0.74-0.89 confidence interval for a single 20-s test). Clinical assessment of balance may benefit from a standardized protocol for center of pressure spectral analysis that provides an adequate relationship between resolution and variance. An algorithm to estimate center of pressure power density spectrum is also proposed.

Comparison of methods of point estimation in occupational epidemiologic studies

Two common study designs of occupational epidemiologic studies are cohort mortality studies, which use the population at risk as a denominator, and proportionate mortality studies, which use the total number of events as a denominator. This study compared the various methods of point estimation for cohort mortality studies, i.e., RR (risk ratio), OR (odds ratio) and SMR (standardized mortality ratio), and those for proportionate mortality studies, i.e., PRR (proportionate risk ratio), POR (proportionate odds ratio) and PMR (proportionate mortality ratio). This study was based on a real dataset of all workers in Metropolitan Toronto, Canada, who applied for compensation for various types of injuries or diseases from the Workers' Compensation Board in 1980. Results showed that within the cohort mortality or proportionate mortality study designs, OR (or POR) in all cases gave the least conservative estimates (farthest away from the null value), while SMR (or PMR) gave the most conservative estimates. The empirical differences between the point estimators were generally small. Our results showed that between study designs the corresponding point estimators were poorly correlated. In addition, this empirical study indicated that the use of the mortality odds ratio did not improve the proportionate mortality study very much in terms of generating results similar to the risk ratio from the cohort mortality design. We drew two conclusions: first, the point estimators within each study design can generally be a good alternative to one another; and second, proportionate mortality studies are not a good approximation for cohort mortality studies.