3,922 research outputs found

    Expendable bubble tiltmeter for geophysical monitoring

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    An unusually rugged highly sensitive and inexpensive bubble tiltmeter has been designed, tested, and built in quantity. These tiltmeters are presently used on two volcanoes and an Alaskan glacier, where they continuously monitor surface tilts of geological interest. This paper discusses the mechanical, thermal, and electric details of the meter, and illustrates its performance characteristics in both large ( > 10^(-4) radian) and small ( < 10^(-6) radian) tilt environments. The meter's ultimate sensitivity is better than 2 X 10^(-8) radians rms for short periods (hours), and its useful dynamic range is greater than 10^4. Included is a short description of field use of the instrument for volcano monitoring

    Acute respiratory diseases: a study on health inequalities

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    Apresentam-se as desigualdades em saúde valendo-se das doenças respiratórias agudas na infância na área de abrangência de um centro de saúde na cidade de São Paulo, Brasil, para subsidiar o planejamento local de ações de promoção da saúde. O trabalho se fundamentou em estudos ecológicos que utilizam a área geográfica como unidade de análise, permitindo a comparação de indicadores de saúde e sócio-econômicos mediante dados censitários. Foram construídos indicadores de "inserção social" e de "qualidade do domicílio", gerando o "índice potencial de exposição" que reflete as condições de risco para o adoecimento por agravos respiratórios. O tratamento estatístico incluiu o agrupamento pela técnica de cluster. Foram identificados quatro grupos sociais homogêneos nas condições de risco para as doenças respiratórias agudas. Os grupos III e IV - com as piores condições sócio-econômicas - mostraram diferenciais importantes em relação aos grupos I e II. Os diferenciais de mortes por pneumonia encontrados, sugerem iniqüidades em saúde. Os resultados permitiram a localização geográfica de maior e menor concentração das carências relativas às condições de vida e a comparação entre os setores censitários para o reconhecimento de necessidades distintas, que subsidiem propostas para a articulação intersetorial.This article discusses health inequalities based on acute childhood respiratory diseases in the coverage area of a health center in the city of São Paulo, Brazil, to help plan local health promotion activities. The work was based on ecological studies using the geographic area as the unit of analysis, allowing a comparison of health and socioeconomic indicators based on census data. Indicators were constructed for "social inclusion" and "housing quality", generating the "potential exposure index", which reflects the respiratory disease risk conditions. Statistical treatment included grouping according to the cluster technique. Four homogenous social groups were identified in terms of risk conditions for acute respiratory diseases. Groups III and IV, with the worst socioeconomic conditions, showed important differences in comparison to groups I and II. The differences in mortality from pneumonia suggest important health inequalities. The results allow the geographic localization of the highest and lowest concentration of needs in terms of living conditions and the comparison of census tracts for recognizing distinct needs, thus supporting proposals for inter-sector collaboration.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

    Hand classification of fMRI ICA noise components

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    We present a practical "how-to" guide to help determine whether single-subject fMRI independent components (ICs) characterise structured noise or not. Manual identification of signal and noise after ICA decomposition is required for efficient data denoising: to train supervised algorithms, to check the results of unsupervised ones or to manually clean the data. In this paper we describe the main spatial and temporal features of ICs and provide general guidelines on how to evaluate these. Examples of signal and noise components are provided from a wide range of datasets (3T data, including examples from the UK Biobank and the Human Connectome Project, and 7T data), together with practical guidelines for their identification. Finally, we discuss how the data quality, data type and preprocessing can influence the characteristics of the ICs and present examples of particularly challenging datasets

    Laser interferometry with translucent and absorbing mechanical oscillators

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    The sensitivity of laser interferometers can be pushed into regimes that enable the direct observation of quantum behaviour of mechanical oscillators. In the past, membranes with subwavelength thickness (thin films) have been proposed as high-mechanical-quality, low-thermal-noise oscillators. Thin films from a homogenous material, however, generally show considerable light transmission accompanied by heating due to light absorption, which typically reduces the mechanical quality and limits quantum opto-mechanical experiments in particular at low temperatures. In this work, we experimentally analyze a Michelson-Sagnac interferometer including a translucent silicon nitride (SiN) membrane with subwavelength thickness. We find that such an interferometer provides an operational point being optimally suited for quantum opto-mechanical experiments with translucent oscillators. In case of a balanced beam splitter of the interferometer, the membrane can be placed at a node of the electro-magnetic field, which simultaneously provides lowest absorption and optimum laser noise rejection at the signal port. We compare the optical and mechanical model of our interferometer with experimental data and confirm that the SiN membrane can be coupled to a laser power of the order of one Watt at 1064 nm without significantly degrading the membrane's quality factor of the order 10^6, at room temperature

    Electrical and network properties of flexible silver-nanowire composite electrodes under mechanical strain

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    Flexible and conductive silver-nanowire photopolymer composites are fabricated and studied under mechanical strain. The initial resistances of the unstretched flexible composites are between 0.27 Ω mm−1 and 1.2 Ω mm−1 for silver-nanowire concentrations between 120 μg cm−2 and 40 μg cm−2. Stretching of the samples leads to an increased resistance by a factor of between 72 for 120 μg cm−2 and 343 for 40 μg cm−2 at elongations of 23%. In order to correlate network morphology and electrical properties, micrographs are recorded during stretching. The Fiber Image Network Evaluation (FINE) algorithm determines morphological silver-nanowire network properties under stretching. For unstretched and stretched samples, an isotropic nanowire network is found with only small changes in fiber orientation. Monte-Carlo simulations on 2D percolation networks of 1D conductive wires and the corresponding network resistance due to tunneling of electrons at nanowire junctions confirm that the elastic polymer matrix under strain exhibits forces in agreement with Hooke's law. By variation of a critical force distribution the resistance curves are accurately reproduced. This results in a model that is dominated by quantum-mechanical tunneling at nanowire junctions explaining the electrical behavior and the sensitivity of nanowire-composites with different filler concentrations under mechanical strain

    Seven unconfirmed ideas to improve future ICU practice

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    With imprecise definitions, inexact measurement tools, and flawed study execution, our clinical science often lags behind bedside experience and simply documents what appear to be the apparent faults or validity of ongoing practices. These impressions are later confirmed, modified, or overturned by the results of the next trial. On the other hand, insights that stem from the intuitions of experienced clinicians, scientists and educators-while often neglected-help place current thinking into proper perspective and occasionally point the way toward formulating novel hypotheses that direct future research. Both streams of information and opinion contribute to progress. In this paper we present a wide-ranging set of unproven 'out of the mainstream' ideas of our FCCM faculty, each with a defensible rationale and holding clear implications for altering bedside management. Each proposition was designed deliberately to be provocative so as to raise awareness, stimulate new thinking and initiate lively dialog.SCOPUS: re.jinfo:eu-repo/semantics/publishe

    Orientation and substrate interaction of adsorbed CO and NO molecules probed by circular dichroism in the angular distribution of photoelectrons

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    The sensitivity and utility of circular dichroism in the angular distribution of photoelectrons (CDAD) as a probe of molecular orientation is demonstrated for adsorbed CO and NO molecules. A comparison between measured CDAD spectra and calculated values for spatially oriented CO and NiCO clearly confirms the well-known perpendicular adsorption for CO on Ni(100), whereas for CO adsorbed on Fe(100) a tilted adsorption geometry was found. For NO/Ni(100) and for NO on the oxygen-preadsorbed Ni(100) surface, an average tilt angle of α=40±10° was observed. In the case of the oxygen-preadsorbed Ni(100) surface, a higher fraction of NO molecules was found to be in a tilted orientation than on the clean surface

    Heritable Variation in Garter Snake Color Patterns in Postglacial Populations

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    Global climate change is expected to trigger northward shifts in the ranges of natural populations of plants and animals, with subsequent effects on intraspecific genetic diversity. Investigating how genetic diversity is patterned among populations that arose following the last Ice Age is a promising method for understanding the potential future effects of climate change. Theoretical and empirical work has suggested that overall genetic diversity can decrease in colonial populations following rapid expansion into postglacial landscapes, with potential negative effects on the ability of populations to adapt to new environmental regimes. The crucial measure of this genetic variation and a population's overall adaptability is the heritable variation in phenotypic traits, as it is this variation that mediates the rate and direction of a population's multigenerational response to selection. Using two large full-sib quantitative genetic studies (NManitoba = 144; NSouth Dakota = 653) and a smaller phenotypic analysis from Kansas (NKansas = 44), we compared mean levels of pigmentation, genetic variation and heritability in three pigmentation traits among populations of the common garter snake, Thamnophis sirtalis, along a north-south gradient, including a postglacial northern population and a putative southern refuge population. Counter to our expectations, we found that genetic variance and heritability for the three pigmentation traits were the same or higher in the postglacial population than in the southern population
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