Assessment of inter-examiner agreement and variability in the manual classification of auditory brainstem response

Abstract Background: The analysis of the Auditory Brainstem Response (ABR) is of fundamental importance to the investigation of the auditory system behaviour, though its interpretation has a subjective nature because of the manual process employed in its study and the clinical experience required for its analysis. When analysing the ABR, clinicians are often interested in the identification of ABR signal components referred to as Jewett waves. In particular, the detection and study of the time when these waves occur (i.e., the wave latency) is a practical tool for the diagnosis of disorders affecting the auditory system. Significant differences in inter-examiner results may lead to completely distinct clinical interpretations of the state of the auditory system. In this context, the aim of this research was to evaluate the inter-examiner agreement and variability in the manual classification of ABR. Methods: A total of 160 ABR data samples were collected, for four different stimulus intensity (80dBHL, 60dBHL, 40dBHL and 20dBHL), from 10 normal-hearing subjects (5 men and 5 women, from 20 to 52 years). Four examiners with expertise in the manual classification of ABR components participated in the study. The Bland-Altman statistical method was employed for the assessment of inter-examiner agreement and variability. The mean, standard deviation and error for the bias, which is the difference between examiners’ annotations, were estimated for each pair of examiners. Scatter plots and histograms were employed for data visualization and analysis. Results: In most comparisons the differences between examiner’s annotations were below 0.1 ms, which is clinically acceptable. In four cases, it was found a large error and standard deviation (>0.1 ms) that indicate the presence of outliers and thus, discrepancies between examiners. Conclusions: Our results quantify the inter-examiner agreement and variability of the manual analysis of ABR data, and they also allows for the determination of different patterns of manual ABR analysis

Contrasting phenotypes of putative proprioceptive and nociceptive trigeminal neurons innervating jaw muscle in rat

BACKGROUND: Despite the clinical significance of muscle pain, and the extensive investigation of the properties of muscle afferent fibers, there has been little study of the ion channels on sensory neurons that innervate muscle. In this study, we have fluorescently tagged sensory neurons that innervate the masseter muscle, which is unique because cell bodies for its muscle spindles are in a brainstem nucleus (mesencephalic nucleus of the 5(th )cranial nerve, MeV) while all its other sensory afferents are in the trigeminal ganglion (TG). We examine the hypothesis that certain molecules proposed to be used selectively by nociceptors fail to express on muscle spindles afferents but appear on other afferents from the same muscle. RESULTS: MeV muscle afferents perfectly fit expectations of cells with a non-nociceptive sensory modality: Opiates failed to inhibit calcium channel currents (I(Ca)) in 90% of MeV neurons, although I(Ca )were inhibited by GABA(B )receptor activation. All MeV afferents had brief (1 msec) action potentials driven solely by tetrodotoxin (TTX)-sensitive Na channels and no MeV afferent expressed either of three ion channels (TRPV1, P2X3, and ASIC3) thought to be transducers for nociceptive stimuli, although they did express other ATP and acid-sensing channels. Trigeminal masseter afferents were much more diverse. Virtually all of them expressed at least one, and often several, of the three putative nociceptive transducer channels, but the mix varied from cell to cell. Calcium currents in 80% of the neurons were measurably inhibited by μ-opioids, but the extent of inhibition varied greatly. Almost all TG masseter afferents expressed some TTX-insensitive sodium currents, but the amount compared to TTX sensitive sodium current varied, as did the duration of action potentials. CONCLUSION: Most masseter muscle afferents that are not muscle spindle afferents express molecules that are considered characteristic of nociceptors, but these putative muscle nociceptors are molecularly diverse. This heterogeneity may reflect the mixture of metabosensitive afferents which can also signal noxious stimuli and purely nociceptive afferents characteristic of muscle

The beta Pictoris association: Catalog of photometric rotational periods of low-mass members and candidate members

We intended to compile the most complete catalog of bona fide members and candidate members of the beta Pictoris association, and to measure their rotation periods and basic properties from our own observations, public archives, and exploring the literature. We carried out a multi-observatories campaign to get our own photometric time series and collected all archived public photometric data time series for the stars in our catalog. Each time series was analyzed with the Lomb-Scargle and CLEAN periodograms to search for the stellar rotation periods. We complemented the measured rotational properties with detailed information on multiplicity, membership, and projected rotational velocity available in the literature and discussed star by star. We measured the rotation periods of 112 out of 117 among bona fide members and candidate members of the beta Pictoris association and, whenever possible, we also measured the luminosity, radius, and inclination of the stellar rotation axis. This represents to date the largest catalog of rotation periods of any young loose stellar association. We provided an extensive catalog of rotation periods together with other relevant basic properties useful to explore a number of open issues, such as the causes of spread of rotation periods among coeval stars, evolution of angular momentum, and lithium-rotation connection.Comment: Forthcoming article, Received: 20 June 2016 / Accepted: 09 September 2016; 40 pages, 2 figures. The online figures A1-A73 are available at CD

Observations on a parasitic nematode (Tetradonematidae) of fire ants, solenopsis (Formicidae), from Mato Grosso.

Parasitic nematodes, Tetradonema sp. (Mermithoidea: Tetradonematidae) were obwserved in the fire ant. Solenopsis invicta Buren, for the first time. Five colonies in a sample of 14 colonies from one site in Mato Grosso were infected. The infection rate among adult workers was 12..5% in one colony and less than 5% in each of the remaining colonies. Adult reproductive males and females, eggs, and juvenile nematodes were observed in the haemocoel of male and worker ants. The infected worker ants often can be recognized by their slightly enlarged gasters, the dorsal scierites of which vable changes in behavior: infected adult males contained normal sperm. An attempt to transmit the nematode to colonies of S. invicta in the United States was unsuccessful.Título em português: Observações sobre um nematóide parasito (Tetradonematidae) da formiga lava-pé, Solenopsis (Formicidae), em Mato Grosso

Rendimento industrial e composição química de milho de alta qualidade protéica em relação a híbridos comerciais.

A dureza do endosperma do milho é atributo essencial para produtores e indústrias que utilizam este cereal como matéria-prima. Porém, os milhos de alta qualidade protéica (Quality Protein Maize – QPM) apresentam alterações na textura do grão, dificultando seu uso comercial. Este trabalho avaliou o rendimento industrial na degerminação do grão e fracionamento do endosperma, e a composição química de uma variedade de milho QPM, em relação a híbridos comerciais de milho comum

Observations on a parasitic nematode (Tetradonematidae) of fire ants, Solenopsis (Formicidae), from Mato Grosso

Foi observado pela primeira vez um nematóide da família Tetradonematidae parasitando Solenopsis invicta Buren. Cinco colônias de um total de quatorze coletadas em Mato Grosso estavam infectadas. A taxa de infecção de adultos foi de 12,5% em uma colônia, e as outras colônias restantes apresentaram menos de 5%. As formigas infectadas podem ser reconhecidas por apresentarem os gásteres ligeiramente maiores e os escleritos dorsais elevados. Não existem outros sinais morfológicos de infecção e nem modificações no comportamento que indiquem a infecção. Os machos adultos infectados tinham esperma normal. A tentativa de transmissão do nematóide para colônias de S. invicta nos Estados Unidos da América foi negativa. Parasitic nematodes, Tetradonema sp. (Mermithoidea: Tetradonematidae) were observed in the fire ant, Solenopsis invicta Buren, for the first time. Five colonies in a sample of 14 colonies from one site in Mato Grosso were infected. The infection rate among adult workers was 12.5% in one colony and less than 5% in each of the remaining colonies. Adult reproductive males and females, eggs, and juvenile nematodes were observed in the haemocoel of male and worker ants. The infected worker ants often can be recognized by their slightly enlarged gasters, the dorsal sclerites of which may have a scalloped appearance. There are no other morphological signs of infection and no observable changes in behavior. lnfected adult males contained normal sperm. An attempt to transmit the nematode to colonies of S. invicta in the United States was unsuccessful.

Análise das taxas de recrutamento e mortalidade para 12 espécies madeireiras em uma floresta na Amazônia Ocidental.

A exploração madeireira nas florestas Amazônicas vem crescendo nas últimas décadas. Junto a esse crescimento, vem também a degradação da flor esta, sendo necessário um sistema de exploração florestal que cause o menor impacto possível a floresta e que seja sustentável ao longo de vários ciclos. O estudo de como a floresta se comporta ao longo do tempo é fundamental para saber se a atividade nela realizada é sustentável. Para entender a dinâmica da floresta são usados algumas variáveis, como: demografia, densidade, diversidade, mortalidade, recrutamento entre outros. Considera-se que em florestas não perturbadas ocorre um equilíbrio dinâmico, onde os indivíduos mortos são substituídos ao longo do tempo por novos indivíduos (recrutas). Neste trabalho é apresentada a análise de alguns desses indicadores para espécies madeireiras em uma floresta manejada sobre regime de manejo florestal de impacto reduzido