Revision of the genus acrochordiceras hyatt, 1877 (Ammonoidea, Middle Triassic): Morphology, biometry, biostratigraphy and intra-specific variability

The family Acrochordiceratidae Arthaber, 1911 ranges in age from latest Spathian to the middle/late Anisian boundary, and it represents a major component of ammonoid faunas during that time. The middle Anisian genus Acrochordiceras Hyatt, 1877 is the most widespread taxon of the family and occurs abundantly worldwide within the low paleolatitude belt. However, there is a profusion of species names available for Acrochordiceras. This excessive diversity at the species level essentially results from the fact that sufficiently large samples were not available, thus leading to a typological approach to its taxonomy. Based on new extensive collections obtained from the Anisian (Middle Triassic) Fossil Hill Member (Star Peak Group, north-west Nevada) for which a high resolution biostratigraphic frame is available, the taxonomy and biostratigraphy of the genus Acrochordiceras Hyatt, 1877 is herein revised with respect to its intra-specific variation. Morphological and biometric studies (c. 550 bedrock-controlled specimens were measured) show that only one species occurs in each stratigraphic level. Continuous ranges of intra-specific variation of studied specimens enable us to synonymize Haydenites Diener, 1907, Silesiacrochordiceras Diener, 1916 and Epacrochordiceras Spath, 1934 with Acrochordiceras Hyatt, 1877. Three stratigraphically successive species are herein recognized in the low paleolatitude middle Anisian faunas from Nevada: A. hatschekii (Diener, 1907), A. hyatti Meek, 1877 and A. carolinae Mojsisovics, 1882. Moreover, an assessment of intra-specific variation of the adult size range does not support recognition of a dimorphic pair (Acrochordiceras and Epacrochordiceras) as previously suggested by other workers (Epacrochordiceras is the compressed and weakly ornamented end-member variant of Acrochordiceras). The successive middle Anisian species of Acrochordiceras form an anagenetic lineage characterized by increasing involution, adult size and intra-specific variation. This taxonomic revision based on new bedrock-controlled collections is thus an important prerequisite before studying the evolution of the group.

Neuroticism, intelligence, and intra-individual variability in elementary cognitive tasks : Testing the mental noise hypothesis. 'Neuroticismo, inteligencia y variabilidad intra-individual en tareas cognitivas elementales : contraste de la hip??tesis del ruido neuronal'

Resumen tomado de la publicaci??n

Prediction of postprandial blood glucose under intra-patient variability and uncertainty and its use in the design of insulin dosing strategies for type 1 diabetic patients

In this thesis I propose a novel method to estimate the dose and injection-to-meal time for low-risk intensive insulin therapy. This dosage-aid system uses an optimization algorithm to determine the insulin dose and injection-to-meal time that minimizes the risk of postprandial hyper- and hypoglycaemia in type 1 diabetic patients. To this end, the algorithm applies a methodology that quantifies the risk of experiencing different grades of hypo- or hyperglycaemia in the postprandial state induced by insulin therapy according to an individual patient’s parameters. This methodology is based on modal interval analysis (MIA). Applying MIA, the postprandial glucose level is predicted with consideration of intra-patient variability and other sources of uncertainty. A worst-case approach is then used to calculate the risk index. In this way, a safer prediction of possible hyper- and hypoglycaemic episodes induced by the insulin therapy tested can be calculated in terms of these uncertainties.

Long-term change, interannual and intra-seasonal variability in climate and glacier mass balance in the Central Greater Caucasus, Russia

Long-term trends, interannual and intra-seasonal variability in the mass-balance record from Djankuat glacier, central Greater Caucasus, Russia, are related to local climate change, synoptic and large-scale anomalies in atmospheric circulation. A clear warming signal emerged in the central Greater Caucasus in the early 1990s, leading to a strong increase in ablation. In the absence of a compensating change in winter accumulation, the net mass balance of Djankuat has declined. The highest value of seasonal ablation on record was registered in the summer of 2000. At the beginning of the 21st century these trends reversed. Ablation was below average even in the summer of 2003, which was unusually warm in western Europe. Precipitation and winter accumulation were high, allowing for a partial recovery of net mass balance. The interannual variability in the components of mass balance is weakly related to the North Atlantic Oscillation (NAO) and the Scandinavian teleconnection patterns, but there is a clear link with the large-scale circulation anomalies represented by the Rossby pattern. Five synoptic categories have been identified for the ablation season of 2005, revealing a strong separation between components of radiation budget, air temperature and daily melt. Air temperature is the main control over melt. The highest values of daily ablation are related to the strongly positive NAO which forces high net radiation, and to the warm and moist advection from the Black Sea.

Spatial intra-annual variability of precipitation based on geostatistics. a case study for the Paraiba do Sul Basin, southeastern Brazil

The emphasis in this research is to evaluate the spatial distribution of the precipitation using a geostatistics approach. Seasonal time scales records considering DJF, MAM, JJA e SON periods performed the analysis. Procedures to evaluate the variogram selection and to produce kriging maps were performed in a GIS environment (ArcGIS®). The results showed that kriging method was very suitable to detect both large changes in the whole area as those local small and subtle changes. Kriging demonstrated be a powerful statistical interpolation method that might be very useful in regions with great complexity in climatology and geomorphology.

Operator variability using different polishing methods and surface geometry of a nanohybrid composite

This study evaluated the operator variability of different finishing and polishing techniques. After placing 120 composite restorations (Tetric EvoCeram) in plexiglassmolds, the surface of the specimens was roughened in a standardized manner. Twelve operators with different experience levels polished the specimens using the following finishing/polishing procedures: method 1 (40 ?m diamond [40D], 15 ?m diamond [15D], 42 ?m silicon carbide polisher [42S], 6 ?m silicon carbide polisher [6S] and Occlubrush [O]); method 2 (40D, 42S, 6S and O); method 3 (40D, 42S, 6S and PoGo); method 4 (40D, 42S and PoGo) and method 5 (40D, 42S and O). The mean surface roughness (Ra) was measured with a profilometer. Differences between the methods were analyzed with non-parametric ANOVA and pairwise Wilcoxon signed rank tests (?=0.05). All the restorations were qualitatively assessed using SEM. Methods 3 and 4 showed the best polishing results and method 5 demonstrated the poorest. Method 5 was also most dependent on the skills of the operator. Except for method 5, all of the tested procedures reached a clinically acceptable surface polish of Ra?0.2 ?m. Polishing procedures can be simplified without increasing variability between operators and without jeopardizing polishing results.

Intra-subject variability in attention-deficit hyperactivity disorder

BACKGROUND: This study is based on a comprehensive survey of the neuropsychological attention-deficit hyperactivity disorder (ADHD) literature and presents the first psychometric analyses of different parameters of intra-subject variability (ISV) in patients with ADHD compared to healthy controls, using the Continuous Performance Test, a Go-NoGo task, a Stop Signal Task, as well as N-back tasks. METHODS: Data of 57 patients with ADHD and 53 age- and gender-matched controls were available for statistical analysis. Different parameters were used to describe central tendency (arithmetic mean, median), dispersion (standard deviation, coefficient of variation, consecutive variance), and shape (skewness, excess) of reaction time distributions, as well as errors (commissions and omissions). RESULTS: Group comparisons revealed by far the strongest effect sizes for measures of dispersion, followed by measures of central tendency, and by commission errors. Statistical control of ISV reduced group differences in the other measures substantially. One (patients) or two (controls) principal components explained up to 67% of the inter-individual differences in intra-individual variability. CONCLUSIONS: Results suggest that, across a variety of neuropsychological tests, measures of ISV contribute best to group discrimination, with limited incremental validity of measures of central tendency and errors. Furthermore, increased ISV might be a unitary construct in ADHD.

Intra-ring variability of Cr, As, Cd, and Pb in red oak revealed by secondary ion mass spectrometry: Implications for environmental biomonitoring

Reconstructing the history of ambient levels of metals by using tree-ring chemistry is controversial. This controversy can be resolved in part through the use of selective microanalysis of individual wood cells. Using a combination of instrumental neutron activation analysis and secondary ion mass spectrometry, we have observed systematic inhomogeneity in the abundance of toxic metals (Cr, As, Cd, and Pb) within annual growth rings of Quercus rubra (red oak) and have characterized individual xylem members responsible for introducing micrometer-scale gradients in toxic metal abundances. These gradients are useful for placing constraints on both the magnitude and the mechanism of heavy metal translocation within growing wood. It should now be possible to test, on a metal-by-metal basis, the suitability of using tree-ring chemistries for deciphering long-term records of many environmental metals.

Variabilidade introduzida pelo operador no processamento dos estudos Gated-SPECT do miocárdio

Introdução – Os estudos Gated – Single Photon Emission Computed Tomography (SPECT) são uma das técnicas de imagiologia cardíaca que mais evoluiu nas últimas décadas. Para a análise das imagens obtidas, a utilização de softwares de quantificação leva a um aumento da reprodutibilidade e exatidão das interpretações. O objetivo deste estudo consiste em avaliar, em estudos Gated-SPECT, a variabilidade intra e interoperador de parâmetros quantitativos de função e perfusão do miocárdio, obtidos com os softwares Quantitative Gated SPECT (QGS) e Quantitative Perfusion SPECT (QPS). Material e métodos – Recorreu-se a uma amostra não probabilística por conveniência de 52 pacientes, que realizaram estudos Gated-SPECT do miocárdio por razões clínicas e que integravam a base de dados da estação de processamento da Xeleris da ESTeSL. Os cinquenta e dois estudos foram divididos em dois grupos distintos: Grupo I (GI) de 17 pacientes com imagens com perfusão do miocárdio normal; Grupo II (GII) de 35 pacientes que apresentavam defeito de perfusão nas imagens Gated-SPECT. Todos os estudos foram processados 5 vezes por 4 operadores independentes (com experiência de 3 anos em Serviços de Medicina Nuclear com casuística média de 15 exames/semana de estudos Gated-SPECT). Para a avaliação da variabilidade intra e interoperador foi utilizado o teste estatístico de Friedman, considerando α=0,01. Resultados e discussão – Para todos os parâmetros avaliados, os respectivos valores de p não traduziram diferenças estatisticamente significativas (p>α). Assim, não foi verificada variabilidade intra ou interoperador significativa no processamento dos estudos Gated-SPECT do miocárdio. Conclusão – Os softwares QGS e QPS são reprodutíveis na quantificação dos parâmetros de função e perfusão avaliados, não existindo variabilidade introduzida pelo operador.

Influência da experiência profissional e da função visual do operador no processamento semiautomático da cintigrafia de perfusão do miocárdio: variabilidade intra e interoperador na determinação dos parâmetros quantitativos

Introdução – A cintigrafia de perfusão do miocárdio (CPM) desempenha um importante papel no diagnóstico, avaliação e seguimento de pacientes com doença arterial coronária, sendo o seu processamento realizado maioritariamente de forma semiautomática. Uma vez que o desempenho dos técnicos de medicina nuclear (TMN) pode ser afetado por fatores individuais e ambientais, diferentes profissionais que processem os mesmos dados poderão obter diferentes estimativas dos parâmetros quantitativos (PQ). Objetivo – Avaliar a influência da experiência profissional e da função visual no processamento semiautomático da CPM. Analisar a variabilidade intra e interoperador na determinação dos PQ funcionais e de perfusão. Metodologia – Selecionou-se uma amostra de 20 TMN divididos em dois grupos, de acordo com a sua experiência no software Quantitative Gated SPECTTM: Grupo A (GA) – TMN ≥600h de experiência e Grupo B (GB) – TMN sem experiência. Submeteram-se os TMN a uma avaliação ortóptica e ao processamento de 21 CPM, cinco vezes, não consecutivas. Considerou-se uma visão alterada quando pelo menos um parâmetro da função visual se encontrava anormal. Para avaliar a repetibilidade e a reprodutibilidade recorreu-se à determinação dos coeficientes de variação, %. Na comparação dos PQ entre operadores, e para a análise do desempenho entre o GA e GB, aplicou-se o Teste de Friedman e de Wilcoxon, respetivamente, considerando o processamento das mesmas CPM. Para a comparação de TMN com visão normal e alterada na determinação dos PQ utilizou-se o Teste Mann-Whitney e para avaliar a influência da visão para cada PQ recorreu-se ao coeficiente de associação ETA. Diferenças estatisticamente significativas foram assumidas ao nível de significância de 5%. Resultados e Discussão – Verificou-se uma reduzida variabilidade intra (<6,59%) e inter (<5,07%) operador. O GB demonstrou ser o mais discrepante na determinação dos PQ, sendo a parede septal (PS) o único PQ que apresentou diferenças estatisticamente significativas (zw=-2,051, p=0,040), em detrimento do GA. No que se refere à influência da função visual foram detetadas diferenças estatisticamente significativas apenas na fração de ejeção do ventrículo esquerdo (FEVE) (U=11,5, p=0,012) entre TMN com visão normal e alterada, contribuindo a visão em 33,99% para a sua variação. Denotaram-se mais diferenças nos PQ obtidos em TMN que apresentam uma maior incidência de sintomatologia ocular e uma visão binocular diminuída. A FEVE demonstrou ser o parâmetro mais consistente entre operadores (1,86%). Conclusão – A CPM apresenta-se como uma técnica repetível e reprodutível, independente do operador. Verificou-se influência da experiência profissional e da função visual no processamento semiautomático da CPM, nos PQ PS e FEVE, respetivamente.

Segmentação de imagens fetais com potencial para desenvolvimento de ferramentas de apoio ao diagnóstico

Programa Doutoral em Engenharia Eletrónica e de Computadores

Variability of gait patterns during unconstrained walking assessed by satellite positioning (GPS).

It is established that the ratio between step length (SL) and step frequency (SF) is constant over a large range of walking speed. However, few data are available about the spontaneous variability of this ratio during unconstrained outdoor walking, in particular over a sufficient number of steps. The purpose of the present study was to assess the inter- and intra-subject variability of spatio-temporal gait characteristics [SL, SF and walk ratio (WR=SL/SF)] while walking at different freely selected speeds. Twelve healthy subjects walked three times along a 100-m athletic track at: (1). a slower than preferred speed, (2). preferred speed and (3). a faster than preferred speed. Two professional GPS receivers providing 3D positions assessed the walking speed and SF with high precision (less than 0.5% error). Intra-subject variability was calculated as the variation among eight consecutive 5-s samples. WR was found to be constant at preferred and fast speeds [0.41 (0.04) m.s and 0.41 (0.05) m.s respectively] but was higher at slow speeds [0.44 (0.05) m.s]. In other words, between slow and preferred speed, the speed increase was mediated more by a change in SF than SL. The intra-subject variability of WR was low under preferred [CV, coefficient of variation = 1.9 (0.6)%] and fast [CV=1.8 (0.5)%] speed conditions, but higher under low speed condition [CV=4.1 (1.5)%]. On the other hand, the inter-subject variability of WR was 11%, 10% and 12% at slow, preferred and fast walking speeds respectively. It is concluded that the GPS method is able to capture basic gait parameters over a short period of time (5 s). A specific gait pattern for slow walking was observed. Furthermore, it seems that the walking patterns in free-living conditions exhibit low intra-individual variability, but that there is substantial variability between subjects.

Genetic variability in Arbuscular Mycorrhizal Fungi : effect on gene transcription of "Oryza Sativa"

AbstractArbuscular Mycorrhizal Fungi (AMF) form obligate symbioses with the majority of land plants. These fungi influence the diversity and productivity of plants. AMF are unusual organisms, harbouring genetically different nuclei in a common cytoplasm (known as heterokaryosis). Genetic variability has been shown between AMF individuals coming from the same population. Recent findings showed that genetic exchange between genetically different AMF individuals was possible. Additionnaly, segregation was shown to occur at spore formation in AMF. These two processes were shown to increase genetic variability between AMF individuals.Because of the difficulty to study these organisms, almost nothing is known about the effect of intra-specific genetic variability in AMF on the plant transcriptome. The aim of this thesis was to bring insights into the effect of intra-specific genetic variability in AMF on plant gene transcription. We demonstrated that genetic exchange could influence expression of some symbiosis specific plant genes and the timing of the colonization of the fungi in plant roots. We also showed that segregation could have a large impact on plant gene transcription. Taken together, these results demonstrated that AMF intra-specific variability could profoundly affect the life of plants by altering various molecular pathways. Moreover, results obtained on rice open a field of research on AMF genetics in impromvment of growth in agricultural plants and should be taken into account for future experiments.RésuméLes champignons endomycorhiziens arbusculaires (CEA) forment une symbiose obligatoire avec la majorité des plantes sur terre. Ces champignons peuvent influencer la diversité et la productivité des plantes avec lesquelles ils forment la symbiose. Les CEA sont des organismes particuliers de part le fait qu'ils possèdent des noyaux génétiquement différents (appelés hétérocaryosis) dans un cytoplasme commun. Il a été montré qu'il existait de la variabilité génétique intra-specific chez les CEA. De plus, des études recentes ont montré que l'échange génétique chez les CEA était possible entre des individus génétiquement différents tout comme la ségrégation qui a aussi été démontrée au moment de la formation des nouvelles spores chez les CEA. Ces deux processus ont été montrés comme pouvant créer aussi de la variabilité génétique intra-specific.Du fait de la difficulté de travailler avec les CEA et à cause de la nouveauté de ces recherches, très peu de choses sont connues sur l'effet de l'échange génétique et de la ségrégation chez les CEA sur les plantes, et particulièrement au niveau moléculaire. Le but de cette thèse a été d'apporter la lumière sur les effets de la viariabilité génétique intra-specific chez les CEA, sur la transcription des gènes chez la plante. Nous avons pu montrer que l'échange génétique pouvait avoir des effets sur l'expression de gènes spécifiques à cette symbiose mais aussi pouvait influencer le timing de colonisation des racines de plantes par les CEA. Nous avons aussi montré que la ségrégation pouvait grandement influencer le transcriptome complet de la plante, et pas seulement les voies métaboliques spécifiques à la symbiose comme cela avait été montré auparavant.L'ensemble de ces résultats démontre l'importance de la variation intra-specific chez les CEA sur les plantes et leur implication sur leur cycle de vie en changeant l'expression de voies métaboliques. De plus, ces résultats obtenus sur le riz ouvrent un champ de recherches sur les plantes destinées à l'agriculture et devraient être pris en compte pour des expériences futures.