Earthquake impacts in old-growth Nothofagus forests in New Zealand

Six stands located on different land forms in mixed old-growth Nothofagus forests in the Matiri Valley (northwest of South Island. New Zealand) were sampled to examine the effects of two recent large earthquakes on tree establishment and tree-ring growth, and how these varied across land forms. 50 trees were cor ed in each stand to determine age structure and the cores were cross-dated to precisely date unusual periods of radial growth. The 1968 earthquake (M = 7.1, epicentre 35 km from the study area) had no discernible impact on the sampled stands. The impact of the 1929 earthquake (M = 7.7, epicentre 20 kin from the study area) varied between stands, depending on whether or not they had been damaged by soil or rock movement. In all stands, the age structures showed a pulse of N. fusca establishment following the 1929 earthquake, with this species dominating establishment in large gaps created by landslides. Smaller gaps, created by branch or tree death, were closed by both N. fusca and N. menziesii. The long period of releases (1929-1945) indicates that direct earthquake damage was not the only cause of tree death, and that many trees died subsequently most likely of pathogen attack or a drought in the early 1930s. The impacts of the 1929 earthquake are compared to a storm in 1905 and a drought in 1974-1978 which also affected forests in the region. Our results confirm that earthquakes are an important factor driving forest dynamics in this tectonically active region, and that the diversity of earthquake impacts is a major source of heterogeneity in forest structure and regeneration.

Open source business strategies in the domain of embedded systems

El tema de este estudio es el aumento de la comprensión teórica y empírica de la estrategia de negocio de código abierto en el dominio de sistemas embebidos por investigar modelos de negocios de código abierto, retos, recursos y capacidades operativas y dinámicas.

Spontaneous pre-stimulus fluctuations in the activity of right fronto-parietal areas influence inhibitory control performance.

Inhibitory control refers to the ability to suppress planned or ongoing cognitive or motor processes. Electrophysiological indices of inhibitory control failure have been found to manifest even before the presentation of the stimuli triggering the inhibition, suggesting that pre-stimulus brain-states modulate inhibition performance. However, previous electrophysiological investigations on the state-dependency of inhibitory control were based on averaged event-related potentials (ERPs), a method eliminating the variability in the ongoing brain activity not time-locked to the event of interest. These studies thus left unresolved whether spontaneous variations in the brain-state immediately preceding unpredictable inhibition-triggering stimuli also influence inhibitory control performance. To address this question, we applied single-trial EEG topographic analyses on the time interval immediately preceding NoGo stimuli in conditions where the responses to NoGo trials were correctly inhibited [correct rejection (CR)] vs. committed [false alarms (FAs)] during an auditory spatial Go/NoGo task. We found a specific configuration of the EEG voltage field manifesting more frequently before correctly inhibited responses to NoGo stimuli than before FAs. There was no evidence for an EEG topography occurring more frequently before FAs than before CR. The visualization of distributed electrical source estimations of the EEG topography preceding successful response inhibition suggested that it resulted from the activity of a right fronto-parietal brain network. Our results suggest that the fluctuations in the ongoing brain activity immediately preceding stimulus presentation contribute to the behavioral outcomes during an inhibitory control task. Our results further suggest that the state-dependency of sensory-cognitive processing might not only concern perceptual processes, but also high-order, top-down inhibitory control mechanisms.

Wide-pulse-high-frequency neuromuscular stimulation of triceps surae induces greater muscle fatigue compared with conventional stimulation.

We compared the extent and origin of muscle fatigue induced by short-pulse-low-frequency [conventional (CONV)] and wide-pulse-high-frequency (WPHF) neuromuscular electrical stimulation. We expected CONV contractions to mainly originate from depolarization of axonal terminal branches (spatially determined muscle fiber recruitment) and WPHF contractions to be partly produced via a central pathway (motor unit recruitment according to size principle). Greater neuromuscular fatigue was, therefore, expected following CONV compared with WPHF. Fourteen healthy subjects underwent 20 WPHF (1 ms-100 Hz) and CONV (50 μs-25 Hz) evoked isometric triceps surae contractions (work/rest periods 20:40 s) at an initial target of 10% of maximal voluntary contraction (MVC) force. Force-time integral of the 20 evoked contractions (FTI) was used as main index of muscle fatigue; MVC force loss was also quantified. Central and peripheral fatigue were assessed by voluntary activation level and paired stimulation amplitudes, respectively. FTI in WPHF was significantly lower than in CONV (21,717 ± 11,541 vs. 37,958 ± 9,898 N·s P<0,001). The reductions in MVC force (WPHF: -7.0 ± 2.7%; CONV: -6.2 ± 2.5%; P < 0.01) and paired stimulation amplitude (WPHF: -8.0 ± 4.0%; CONV: -7.4 ± 6.1%; P < 0.001) were similar between conditions, whereas no change was observed for voluntary activation level (P > 0.05). Overall, our results showed a different motor unit recruitment pattern between the two neuromuscular electrical stimulation modalities with a lower FTI indicating greater muscle fatigue for WPHF, possibly limiting the presumed benefits for rehabilitation programs.

Pulse wave analysis of aortic pressure: diastole should also be considered.

BACKGROUND: : The systolic augmentation index (sAix), calculated from the central aortic pulse wave (reconstructed from the noninvasive recording of the radial pulse with applanation tonometry), is widely used as a simple index of central arterial stiffness, but has the disadvantage of also being influenced by the timing of the reflected with respect to the forward pressure wave, as shown by its inverse dependence on heart rate (HR). During diastole, the central aortic pulse also contains reflected waves, but their relationship to arterial stiffness and HR has not been studied. METHODS: : In 48 men and 45 women, all healthy, with ages ranging from 19 to 70 years, we measured pulse wave velocity (PWV, patients supine), a standard evaluator of arterial stiffness, and carried out radial applanation tonometry (patients sitting and supine). The impact of reflected waves on the diastolic part of the aortic pressure waveform was quantified in the form of a diastolic augmentation index (dAix). RESULTS: : Across ages, sexes, and body position, there was an inverse relationship between the sAix and the dAix. When PWV and HR were added as covariates to a prediction model including age, sex and body position as main factors, the sAix was directly related to PWV (P < 0.0001) and inversely to HR (P < 0.0001). With the same analysis, the dAix was inversely related to PWV (P < 0.0001) and independent of HR (P = 0.52). CONCLUSION: : The dAix has the same degree of linkage to arterial stiffness as the more conventional sAix, while being immune to the confounding effect of HR. The quantification of diastolic aortic pressure augmentation by reflected waves could be a useful adjunct to pulse wave analysis.

Profound impact of uncomplicated pregnancy on diastolic, but not systolic pulse contour of aortic pressure

RESUME: L'objectif de cette étude était de déterminer l'impact de la grossesse non compliquée sur l'onde de pouls de la pression aortique centrale. Méthode 66 femmes au total avec une grossesse simple ont été réparties en trois groupes selon le stade de leur gestation: premier trimestre (T1, n=22), deuxième trimestre (T2, n=20) et troisième trimestre (T3, n=24). Le groupe contrôle (C, n=21) était constitué de femmes non enceintes, en bonne santé habituelle, prenant une contraception oestroprogestative. La tonométrie d'aplanation a été utilisée pour l'acquisition des ondes de pouls centrale un appareil disponible dans le commerce (SphygmoCor) permet l'enregistrement de l'onde de pouls périphérique avec un tonomètre d'aplanation de l'artère radiale au niveau du poignet, puis effectue sa transformation en sa forme centrale, grâce à une analyse de Fourrier et une fonction de transfert. L'influence des ondes réfléchies sur l'onde de pouls a été déterminée non seulement pendant la systole (augmentation systolique), comme on procède habituellement dans l'analyse de l'onde de pouls, mais aussi pendant la diastole (augmentation diastolique). Résultats Au cours de la grossesse, les pressions centrales systolique et diastolique sont restées inchangées et comparables aux valeurs mesurées chez les femmes qui ne sont pas enceintes. Dans le groupe contrôle, l'augmentation systolique s'élevait à 8.1±7.5% de la pression de pouls ; il n'y avait pas de différence statistiquement significative avec les valeurs obtenues chez les femmes enceintes, et ce, à n'importe quel stade de la grossesse (T1 : 4.6±11.4%, T2: 5.0±9.3%, T3 : 4.7±8.1%). Par contre, l'amplitude de l'augmentation diastolique diminuait avec la progression de la grossesse (C 6.5±2.4%, T1 : 5.2±3.1%, T2 : 3.8±2.6%; P=0.002 versus C; T3 : 2.3±2.0%; P<0.0001 versus C et P=0.004 versus T 1). Conclusion La grossesse ne modifie pas la forme de l'onde de pouls systolique centrale, ce qui implique de la part du système cardiovasculaire une adaptation fine à la demande croissante de flux sanguin, et ce, à tous les stades de la grossesse. Par contre, l'amplitude de l'onde de réflexion atteignant l'aorte pendant la diastole diminue progressivement au cours de la grossesse. Perspectives De récentes études montrent qu'une valeur anormalement haute de l'augmentation systolique de la pression centrale, comme on peut la déterminer avec la tonométrie d'aplanation, pourrait être un indice de trouble hypertensif de la grossesse débutant. Cette technique simple pourrait être d'autant plus facile à mettre en oeuvre si les valeurs normales pour l'augmentation systolique étaient indépendantes du stade de la grossesse, comme le suggèrent nos résultats, du moins pour les mesures prises en position assise.

Sistema de Informação Geográfica na Internet para apoio à gestão de Infra-estruturas, baseado em ferramentas Open Source

A gestão de infra-estruturas é um processo de coordenação, avaliação sistemática e manutenção efectiva das infra-estruturas relacionadas com os serviços básicos. A gestão eficaz de infra-estruturas exige que a disposição dos equipamentos no meio urbano seja conhecida, bem como sua relação com o uso do solo. Sendo a gestão de infra-estruturas uma questão de natureza espacial, é natural pensar na utilização de um Sistema de Informação Geográfica como ferramenta com potencial de grande utilidade, pois permite a georreferenciação de dados espaciais e sua interligação com atributos alfanuméricos, para além da realização de análises complexas e a possibilidade de simular diversos cenários de modo a propiciar uma tomada de decisão eficaz. O elevado custo das licenças e a especificidade de utilização a nível técnico, tornam-se obstáculos na criação e manutenção de dados geográficos. Contudo os recentes desenvolvimentos em tecnologias da Internet têm contribuído para o acesso, publicação, exploração e distribuição da Informação Geográfica. A utilização de SIG distribuídos na Internet (WebGIS), nomeadamente na vertente livre, pode ser uma solução adequada visto que coloca funcionalidades de SIG ao alcance de utilizadores, através de um simples browser, sem necessidade de investimentos em relação a software ou mesmo em formação técnica especializada. Assim, com este projecto pretende-se a criação de um sistema de Informação geográfico na Internet, utilizando softwares livres, que disponibiliza toda a informação geográfica e alfanumérica das infra-estruturas construídas e sob a responsabilidade do Ministério das Infra-estruturas e Economia Marítima, permitindo a visualização e a realização de pesquisas e operações de análise.

Fecal Source Tracking in Iowa, 2004

Water fact sheet for Iowa Department of Natural Resources and the Geological Bureau.

Bacteria Source Tracking in Lake Darling Watershed, 2005

Monitoring of Iowa's surface waters during the past five years has demonstrated the regular occurrence of fecel bacteria in surface water resources.

First impressions matter: Signalling as a source of policy dynamics

We first establish that policymakers on the Bank of England's Monetary PolicyCommittee choose lower interest rates with experience. We then reject increasingconfidence in private information or learning about the structure of the macroeconomy as explanations for this shift. Instead, a model in which voters signal theirhawkishness to observers better fits the data. The motivation for signalling is consistent with wanting to control inflation expectations, but not career concerns orpleasing colleagues. There is also no evidence of capture by industry. The papersuggests that policy-motivated reputation building may be important for explainingdynamics in experts' policy choices.

Bands width, credibility and exchange risk: Lessons from the EMS experience

This paper presents an analysis of the credibility of the EMScurrencies that covers the period before and after the increase in thebands of fluctuation. Our credibility indicator is based on the inferredprobabilities derived from the estimation of a Markov-switching model(Hamilton (1989)) applied to the expected rate of depreciation. Theresults show that, for most of the currencies, credibility has improved,at least transitorily, after the increase in the bands. However, for allcurrencies, the credibility measured by the indicator proposed in thispaper has been eroded recently even with the widened bands.

Source inference of exogenous gamma-hydroxybutyric acid (GHB) administered to humans by means of carbon isotopic ratio analysis: novel perspectives regarding forensic investigation and intelligence issues.

γ-Hydroxybutyric acid (GHB) is an endogenous short-chain fatty acid popular as a recreational drug due to sedative and euphoric effects, but also often implicated in drug-facilitated sexual assaults owing to disinhibition and amnesic properties. Whilst discrimination between endogenous and exogenous GHB as required in intoxication cases may be achieved by the determination of the carbon isotope content, such information has not yet been exploited to answer source inference questions of forensic investigation and intelligence interests. However, potential isotopic fractionation effects occurring through the whole metabolism of GHB may be a major concern in this regard. Thus, urine specimens from six healthy male volunteers who ingested prescription GHB sodium salt, marketed as Xyrem(®), were analysed by means of gas chromatography/combustion/isotope ratio mass spectrometry to assess this particular topic. A very narrow range of δ(13)C values, spreading from -24.810/00 to -25.060/00, was observed, whilst mean δ(13)C value of Xyrem(®) corresponded to -24.990/00. Since urine samples and prescription drug could not be distinguished by means of statistical analysis, carbon isotopic effects and subsequent influence on δ(13)C values through GHB metabolism as a whole could be ruled out. Thus, a link between GHB as a raw matrix and found in a biological fluid may be established, bringing relevant information regarding source inference evaluation. Therefore, this study supports a diversified scope of exploitation for stable isotopes characterized in biological matrices from investigations on intoxication cases to drug intelligence programmes.