Analysis Techniques (analysis + techniques)

Distribution by Scientific Domains
Distribution within Medical Sciences

Kinds of Analysis Techniques

  • data analysis techniques
  • image analysis techniques
  • thermal analysis techniques

  • Selected Abstracts

    Study of Fatigue Damage Micromechanisms in a Duplex Stainless Steel by Complementary Analysis Techniques

    Ahmed El Bartali
    The low-cycle fatigue (LCF) damage micromechanisms are studied in a duplex stainless steel at room temperature using complementary analysis techniques. Surface damage is observed in real-time with an in-situ microscopic device during a low-cycle fatigue test. Slip systems activated in each grain in each phase are identified from SEM photographs and EBSD measurements. The surface relief appeared at the end of the test is measured with an interferometric profilometer. Displacement and strain fields on the microstructural scale are calculated using DIC technique from surface images taken during cycling. Observations were combined to analyse damage mechanisms from slip marking appearance to strain localisation and crack initiation. [source]

    Preliminary Observations on Phase Relations in the "V2O3,FeO" and V2O3,TiO2 Systems from 1400°C to 1600°C in Reducing Atmospheres

    Theresa Coetsee
    Phase relations within the "V2O3,FeO" and V2O3,TiO2 oxide systems were determined using the quench technique. Experimental conditions were as follows: partial oxygen pressures of 3.02 × 10,10, 2.99 × 10,9, and 2.31 × 10,8 atm at 1400°, 1500°, and 1600°C, respectively. Analysis techniques that were used to determine the phase relations within the reacted samples included X-ray diffractometry, electron probe microanalysis (energy-dispersive spectroscopy and wavelength-dispersive spectroscopy), and optical microscopy. The solid-solution phases M2O3, M3O5, and higher Magneli phases (MnO2n,1, where M = V, Ti) were identified in the V2O3,TiO2 system. In the "V2O3,FeO" system, the solid-solution phases M2O3 and M3O4 (where M = V, Ti), as well as liquid, were identified. [source]

    Schiff base substitute polyphenol and its metal complexes derived from o -vanillin with 2,3-diaminopyridine: synthesis, characterization, thermal, and conductivity properties

    smet Kaya
    Abstract Poly-2,3 - bis[(2-hydroxy-3-methoxyphenyl)methylene]diamino pyridine (PHMPMDAP) that a new Schiff base polymer has been synthesized and characterized by spectroscopy, elemental, and thermal analyses techniques. This azomethine polymer was found to form complexes readily with Cu(II), Zn(II), Co(II), Pb(II), and Fe(II). From IR and UV-Vis studies, the phenolic oxygen and imine nitrogen of the ligand were found to be the coordination sites. Thermogravimetric analysis (TGA) data indicate the polymer to be more stable than the monomer. The structure of the polymer obtained was confirmed by FT-IR, UV-Vis, 13C-NMR, and 1H-NMR. Characterization was undertaken by TGA, size exclusion chromatography (SEC), and solubility tests. Also, electrical conductivities of PHMPMDAP and polymer,metal complexes are measured by four probe technique. Copyright © 2008 John Wiley & Sons, Ltd. [source]


    CRIMINOLOGY, Issue 2 2007
    Specialization in violence is an important scientific and policy topic, and over the past several decades, many analysis techniques for studying specialization have emerged. Research in this area continues to be hampered, however, by remaining methodological problems. To overcome these problems, we propose a new method for studying specialization in violence based on an item-response theory measurement approach that is implemented through a multilevel regression model. Our approach defines specialization as an individual level latent variable, takes into account the inherent confounds between specialization and overall level of offending, and gauges specialization relative to the population base rates of each offense. Our method also enables researchers to 1) estimate the extent and statistical significance of specialization, 2) assess the stability of specialization over time, and 3) relate specialization to explanatory variables. Using data from three studies, we found substantial levels of specialization in violence, considerable stability in specialization over time, and several significant and relatively consistent relationships of specialization to explanatory variables such as gender, parental education, and risk-seeking. [source]

    A framework for evidence-based mental health care and policy

    L. Salvador-Carulla
    Objective:, Care planning integrates a growing number of disciplines, research fields and analysis techniques. A framework of the main areas of interest with regard to evidence-based health care in mental health is provided here. Method:, The framework is based on the experience of working with data analysts and health and social decision makers at the PSICOST/RIRAG network, a Spanish research association which includes psychiatrists, health economists and health policy experts, as well as on a review of the literature. Results:, Three main areas have been identified and described here: outcomes management, knowledge discovery from data, and decision support systems. Their use in mental health care is reviewed. Conclusion:, It is important to promote bridging strategies among these new fields in order to enhance communication and information transfer between the different parts involved in mental health decision making: i) clinicians and epidemiologists, ii) data analysts, iii) care policy makers and other end-users. [source]

    An experimental investigation of water level effects on the dynamic behaviour of a large arch dam

    Jean Proulx
    Abstract The need for full-scale dynamic tests, which are recognized as the most reliable method to evaluate a structure's vibration properties, is increasing as new analysis techniques are developed that take into account the complex interaction phenomenons that occur in dam,reservoir,foundation systems. They are extremely useful to obtain reliable data for the calibration of newly developed numerical methods. The Earthquake Engineering and Structural Dynamics Research Center (CRGP) at the University of Sherbrooke has been developing and applying dynamic testing methods for large structures in the past 10 years. This paper presents the experimental evaluation of the effects of the varying water level on the dynamic response of the 180 m Emosson arch dam in Switzerland. Repeated forced-vibration tests were carried out on the dam during four different periods of the reservoir's filling cycle during a one-year span. Acceleration and hydrodynamic pressure frequency responses were obtained at several locations while the dam was subjected to horizontal harmonic loading. The variation of the resonant frequencies as a function of the reservoir level is investigated. A summary of the ongoing numerical correlation phase with a three-dimensional finite element model for the dam,reservoir,foundation system is also presented. Copyright © 2001 John Wiley & Sons, Ltd. [source]

    Study of Fatigue Damage Micromechanisms in a Duplex Stainless Steel by Complementary Analysis Techniques

    Ahmed El Bartali
    The low-cycle fatigue (LCF) damage micromechanisms are studied in a duplex stainless steel at room temperature using complementary analysis techniques. Surface damage is observed in real-time with an in-situ microscopic device during a low-cycle fatigue test. Slip systems activated in each grain in each phase are identified from SEM photographs and EBSD measurements. The surface relief appeared at the end of the test is measured with an interferometric profilometer. Displacement and strain fields on the microstructural scale are calculated using DIC technique from surface images taken during cycling. Observations were combined to analyse damage mechanisms from slip marking appearance to strain localisation and crack initiation. [source]

    Feature extraction by autoregressive spectral analysis using maximum likelihood estimation: internal carotid arterial Doppler signals

    EXPERT SYSTEMS, Issue 4 2008
    Elif Derya Übeyli
    Abstract: In this study, Doppler signals recorded from the internal carotid artery (ICA) of 97 subjects were processed by personal computer using classical and model-based methods. Fast Fourier transform (classical method) and autoregressive (model-based method) methods were selected for processing the ICA Doppler signals. The parameters in the autoregressive method were found by using maximum likelihood estimation. The Doppler power spectra of the ICA Doppler signals were obtained by using these spectral analysis techniques. The variations in the shape of the Doppler spectra as a function of time were presented in the form of sonograms in order to obtain medical information. These Doppler spectra and sonograms were then used to compare the applied methods in terms of their frequency resolution and the effects in determination of stenosis and occlusion in the ICA. Reliable information on haemodynamic alterations in the ICA can be obtained by evaluation of these sonograms. [source]

    Research Trends in Textiles and Clothing: An Analysis of Three Journals, 1980,1999

    Sharron J. Lennon
    The purpose of this research was to assess trends in research, research strategies, data analysis techniques, funding sources, affiliations, and the use of theoretical frameworks in textiles and clothing research. Empirical research focused on textiles and clothing and published in three home economics,related journals,Journal of Family and Consumer Sciences, Family and Consumer Science Research Journal, and Clothing and Textiles Research Journal,from 1980 to 1999 was content analyzed (N = 586). Although survey methodology and experimentation were the first and second most-used research strategies in all but one 5-year period from 1980 to 1999, fieldwork has increased. Data analysis techniques were primarily quantitative, with increases in the use of some advanced statistical techniques. However, the qualitative treatment of data also increased. Suggestions for graduate education and faculty development are offered. [source]

    PCR DGGE and RT-PCR DGGE show diversity and short-term temporal stability in the Clostridium coccoides,Eubacterium rectale group in the human intestinal microbiota

    Johanna Maukonen
    Abstract As the Clostridium coccoides,Eubacterium rectale (Erec; clostridial phylogenetic cluster XIVa) group is one of the major groups of the human intestinal microbiota, DNA- and RNA-based population analysis techniques (denaturing gradient gel electrophoresis; DGGE) were developed and applied to assess the diversity and temporal stability (6 months,2 years) of this faecal clostridial microbiota in 12 healthy adults. The stability of the Erec group was compared with the stability of the predominant bacterial microbiota, which was also assessed with PCR-DGGE. In addition, the Erec group was quantified with a hybridization-based method. According to our results, the Erec group was diverse in each subject, but interindividual uniqueness was not as clear as that of the predominant bacteria. The Erec group was found to be temporally as stable as the predominant bacteria. Over 200 clones obtained from two samples proved the developed method to be specific. However, the amount of bacteria belonging to the Erec group was not related to the diversity of that same bacterial group. In conclusion, the newly developed DGGE method proved to be a valuable and specific tool for the direct assessment of the stability of the Erec group, demonstrating diversity in addition to short-term stability in most of the subjects studied. [source]

    Coordination complexes of functionalized pyrazines with metal ions: reagents for the controlled release of flavourant molecules at elevated temperatures

    Colin Baillie
    Abstract The potential for stabilization of volatile flavourant molecules such as functionalized pyrazines by coordination to metal ions, and the application of the resultant coordination complexes as controlled release agents at elevated temperatures were explored. New complexes containing the flavourant molecules 2,3,5-trimethylpyrazine (TMP), 2-ethyl-3-methylpyrazine (EMP) and 2-acetylpyrazine (ACP) with copper(II) and copper(I) salts were prepared and structurally characterized. Representative examples of known copper(II) and calcium(II) complexes containing pyrazine carboxylic acids were also prepared. The complexes were examined by thermal analysis techniques and demonstrated, by a combination of thermogravimetric (TGA) and pyrolysis GC,MS analyses, to act as convenient reagents for the release of the parent pyrazine at elevated temperatures. Thus, pyrolysis GC,MS revealed that the complex [Cu3Cl3(EMP)2]n cleanly releases EMP in 96.5% selectivity at 200 °C. Of particular significance is that the calcium complex [Ca(3-aminopyrazine-2-carboxylate)2·H2O], under ramped pyrolysis conditions, was shown to undergo decarboxylation prior to the release of 2-aminopyrazine (AMP), as essentially the only volatile component, in the temperature range 600,800 °C. This finding provides a precedent for the application of complexes of pyrazinecarboxylate salts with metal ions (of which an almost infinite number of combinations is potentially available) as controlled release agents of the parent pyrazine molecule at elevated temperatures, suitable for exploitation by the foodstuffs, flavour and fragrance industries. Copyright © 2006 John Wiley & Sons, Ltd. [source]

    A Genetic Approach to Detecting Clusters in Point Data Sets

    Jamison Conley
    Spatial analysis techniques are widely used throughout geography. However, as the size of geographic data sets increases exponentially, limitations to the traditional methods of spatial analysis become apparent. To overcome some of these limitations, many algorithms for exploratory spatial analysis have been developed. This article presents both a new cluster detection method based on a genetic algorithm, and Programs for Cluster Detection, a toolkit application containing the new method as well as implementations of three established methods: Openshaw's Geographical Analysis Machine (GAM), case point-centered searching (proposed by Besag and Newell), and randomized GAM (proposed by Fotheringham and Zhan). We compare the effectiveness of cluster detection and the runtime performance of these four methods and Kulldorf's spatial scan statistic on a synthetic point data set simulating incidence of a rare disease among a spatially variable background population. The proposed method has faster average running times than the other methods and significantly reduces overreporting of the underlying clusters, thus reducing the user's postprocessing burden. Therefore, the proposed method improves upon previous methods for automated cluster detection. The results of our method are also compared with those of Map Explorer (MAPEX), a previous attempt to develop a genetic algorithm for cluster detection. The results of these comparisons indicate that our method overcomes many of the problems faced by MAPEX, thus, we believe, establishing that genetic algorithms can indeed offer a viable approach to cluster detection. [source]

    Influence of Race on Household Residential Utility

    M William Sermons
    Residential location choice models are an important tool employed by urban geographers, planners, and transportation engineers for understanding household residential location behavior and for predicting future residential location activity. Racial segregation and residential racial preferences have been studied extensively using a variety of analysis techniques in social science research, but racial preferences have generally not been adequately incorporated into residential location choice models. This research develops residential location choice model specifications with a variety of alternative methods of addressing racial preferences in residential location decisions. The research tests whether social class, family structure, and in-group racial preferences are sufficient to explain household sensitivity to neighborhood racial composition. The importance of the interaction between the proportion of in-group race neighbors and other-race neighbors is also evaluated. Models for the San Francisco Bay metropolitan area are estimated and evidence of significant avoidance behavior by households of all races is found. The results suggest that social class differences, family structure differences, and in-group racial preferences alone are not sufficient to explain household residential racial preference and that households of all races practice racial avoidance behavior. Particularly pronounced avoidance of black neighbors by Asian households, Hispanic neighbors by black households, and Asian neighbors by white households are found. Evidence of a decrease in household racial avoidance intensity in neighborhoods with large numbers of own-race neighbors is also found. [source]

    Climatic signals in growth and its relation to ENSO events of two Prosopis species following a latitudinal gradient in South America

    Abstract Semiarid environments throughout the world have lost a major part of their woody vegetation and biodiversity due to the effects of wood cutting, cattle grazing and subsistence agriculture. The resulting state is typically used for cattle production, but the productivity of these systems is often very low, and erosion of the unprotected soil is a common problem. Such dry-land degradation is of great international concern, not only because the resulting state is hardly productive but also because it paves the way to desertification. The natural distribution of the genus Prosopis includes arid and semiarid zones of the Americas, Africa and Asia, but the majority of the Prosopis species are, however, native to the Americas. In order to assess a likely gradient in the response of tree species to precipitation, temperature and their connection to El Niño southern oscillation (ENSO) events, two Prosopis species were chosen along a latitudinal gradient in Latin America, from northern Peru to central Chile: Prosopis pallida from a semi-arid land in northern and southern Peru and P. chilensis from a semiarid land in central Chile. Growth rings of each species were crossdated at each sampling site using classical dendrochronological techniques. Chronologies were related with instrumental climatic records in each site, as well as with SOI and N34 series. Cross-correlation, spectral and wavelet analysis techniques were used to assess the relation of growth with precipitation and temperature. Despite the long distance among sites, the two Prosopis species presented similar responses. Thus, the two species' growth is positively correlated to precipitation, while with temperature it is not. In northern Peru, precipitation and growth of P. pallida present a similar cyclic pattern, with a period of around 3 years. On the other hand, P. pallida in southern Peru, and P. chilensis also present this cyclic pattern, but also another one with lower frequency, coinciding with the pattern of precipitation. Both cycles are within the range of the ENSO band. [source]

    Net changes in regional woody vegetation cover and carbon storage in Texas Drylands, 1937,1999

    Abstract Although local increases in woody plant cover have been documented in arid and semiarid ecosystems worldwide, there have been few long-term, large-scale analyses of changes in woody plant cover and aboveground carbon (C) stocks. We used historical aerial photography, contemporary Landsat satellite data, field observations, and image analysis techniques to assess spatially specific changes in woody vegetation cover and aboveground C stocks between 1937 and 1999 in a 400-km2 region of northern Texas, USA. Changes in land cover were then related to topo-edaphic setting and historical land-use practices. Mechanical or chemical brush management occurred over much of the region in the 1940,1950s. Rangelands not targeted for brush management experienced woody cover increases of up to 500% in 63 years. Areas managed with herbicides, mechanical treatments or fire exhibited a wide range of woody cover changes relative to 1937 (,75% to + 280%), depending on soil type and time since last management action. At the integrated regional scale, there was a net 30% increase in woody plant cover over the 63-year period. Regional increases were greatest in riparian corridors (33%) and shallow clay uplands (26%) and least on upland clay loams (15%). Allometric relationships between canopy cover and aboveground biomass were used to estimate net aboveground C storage changes in upland (nonriparian) portions of regional landscapes. Carbon stocks increased from 380 g C m,2 in 1937 to 500 g C m,2 in 1999, a 32% net increase across the 400 km2 region over the 63-year period. These plant C storage change estimates are highly conservative in that they did not include the substantial increases in woody plant cover observed within riparian landscape elements. Results are discussed in terms of implications for ,carbon accounting' and the global C cycle. [source]

    In Situ Growth of Mesoporous SnO2 on Multiwalled Carbon Nanotubes: A Novel Composite with Porous-Tube Structure as Anode for Lithium Batteries,

    Z. Wen
    Abstract A novel mesoporous-nanotube hybrid composite, namely mesoporous tin dioxide (SnO2) overlaying on the surface of multiwalled carbon nanotubes (MWCNTs), was prepared by a simple method that included in situ growth of mesoporous SnO2 on the surface of MWCNTs through hydrothermal method utilizing Cetyltrimethylammonium bromide (CTAB) as structure-directing agents. Nitrogen adsorption,desorption, X-ray diffraction and transmission electron microscopy analysis techniques were used to characterize the samples. It was observed that a thin layer tetragonal SnO2 with a disordered porous was embedded on the surface of MWCNTs, which resulted in the formation of a novel mesoporous-nanotube hybrid composite. On the base of TEM analysis of products from controlled experiment, a possible mechanism was proposed to explain the formation of the mesoporous-nanotube structure. The electrochemical properties of the samples as anode materials for lithium batteries were studied by cyclic voltammograms and Galvanostatic method. Results showed that the mesoporous-tube hybrid composites displayed higher capacity and better cycle performance in comparison with the mesoporous tin dioxide. It was concluded that such a large improvement of electrochemical performance within the hybrid composites may in general be related to mesoporous-tube structure that possess properties such as one-dimensional hollow structure, high-strength with flexibility, excellent electric conductivity and large surface area. [source]

    Parent-Identified Barriers to Pediatric Health Care: A Process-Oriented Model

    Elisa J. Sobo
    Objective. To further understand barriers to care as experienced by health care consumers, and to demonstrate the importance of conjoining qualitative and quantitative health services research. Data Sources. Transcripts from focus groups conducted in San Diego with English- and Spanish-speaking parents of children with special health care needs. Study Design. Participants were asked about the barriers to care they had experienced or perceived, and their strategies for overcoming these barriers. Using elementary anthropological discourse analysis techniques, a process-based conceptual model of the parent experience was devised. Principal Findings. The analysis revealed a parent-motivated model of barriers to care that enriched our understanding of quantitative findings regarding the population from which the focus group sample was drawn. Parent-identified barriers were grouped into the following six temporally and spatially sequenced categories: necessary skills and prerequisites for gaining access to the system; realizing access once it is gained; front office experiences; interactions with physicians; system arbitrariness and fragmentation; outcomes that affect future interaction with the system. Key to the successful navigation of the system was parents' functional biomedical acculturation; this construct likens the biomedical health services system to a cultural system within which all parents/patients must learn to function competently. Conclusions. Qualitative analysis of focus group data enabled a deeper understanding of barriers to care,one that went beyond the traditional association of marker variables with poor outcomes ("what") to reveal an understanding of the processes by which parents experience the health care system ("how,""why") and by which disparities may arise. Development of such process-oriented models furthers the provision of patient-centered care and the creation of interventions, programs, and curricula to enhance such care. Qualitative discourse analysis, for example using this project's widely applicable protocol for generating experientially based models, can enhance our knowledge of the parent/patient experience and aid in the development of more powerful conceptualizations of key health care constructs. [source]

    Discrete dynamic Bayesian network analysis of fMRI data

    HUMAN BRAIN MAPPING, Issue 1 2009
    John Burge
    Abstract We examine the efficacy of using discrete Dynamic Bayesian Networks (dDBNs), a data-driven modeling technique employed in machine learning, to identify functional correlations among neuroanatomical regions of interest. Unlike many neuroimaging analysis techniques, this method is not limited by linear and/or Gaussian noise assumptions. It achieves this by modeling the time series of neuroanatomical regions as discrete, as opposed to continuous, random variables with multinomial distributions. We demonstrated this method using an fMRI dataset collected from healthy and demented elderly subjects (Buckner, et al., 2000: J Cogn Neurosci 12:24-34) and identify correlates based on a diagnosis of dementia. The results are validated in three ways. First, the elicited correlates are shown to be robust over leave-one-out cross-validation and, via a Fourier bootstrapping method, that they were not likely due to random chance. Second, the dDBNs identified correlates that would be expected given the experimental paradigm. Third, the dDBN's ability to predict dementia is competitive with two commonly employed machine-learning classifiers: the support vector machine and the Gaussian naïve Bayesian network. We also verify that the dDBN selects correlates based on non-linear criteria. Finally, we provide a brief analysis of the correlates elicited from Buckner et al.'s data that suggests that demented elderly subjects have reduced involvement of entorhinal and occipital cortex and greater involvement of the parietal lobe and amygdala in brain activity compared with healthy elderly (as measured via functional correlations among BOLD measurements). Limitations and extensions to the dDBN method are discussed. Hum Brain Mapp, 2009. © 2007 Wiley-Liss, Inc. [source]

    fMRI analysis for motor paradigms using EMG-based designs: A validation study

    HUMAN BRAIN MAPPING, Issue 11 2007
    Anne-Fleur van Rootselaar
    Abstract The goal of the present validation study is to show that continuous surface EMG recorded simultaneously with 3T fMRI can be used to identify local brain activity related to (1) motor tasks, and to (2) muscle activity independently of a specific motor task, i.e. spontaneous (abnormal) movements. Five healthy participants performed a motor task, consisting of posture (low EMG power), and slow (medium EMG power) and fast (high EMG power) wrist flexion,extension movements. Brain activation maps derived from a conventional block design analysis (block-only design) were compared with brain activation maps derived using EMG-based regressors: (1) using the continuous EMG power as a single regressor of interest (EMG-only design) to relate motor performance and brain activity, and (2) using EMG power variability as an additional regressor in the fMRI block design analysis to relate movement variability and brain activity (mathematically) independent of the motor task. The agreement between the identified brain areas for the block-only design and the EMG-only design was excellent for all participants. Additionally, we showed that EMG power variability correlated well with activity in brain areas known to be involved in movement modulation. These innovative EMG-fMRI analysis techniques will allow the application of novel motor paradigms. This is an important step forward in the study of both the normally functioning motor system and the pathophysiological mechanisms in movement disorders. Hum Brain Mapp, 2007. © 2007 Wiley-Liss, Inc. [source]

    A study of best practices in training transfer and proposed model of transfer

    Lisa A. Burke
    Data were gathered from a sample of training professionals of an American Society of Training and Development (ASTD) chapter in the southern United States regarding best practices for supporting training transfer. Content analysis techniques, based on a rigorous methodology proposed by Insch, Moore, & Murphy (1997), were used to analyze the rich data. Findings suggest that interventions for bolstering training transfer are best carried out in the work context and design and delivery phase, take place after training or during, and involve trainers and supervisors. Activities garnering top attention from trainers as best practices include (starting with most frequently reported) supervisory support activities, coaching, opportunities to perform, interactive training activities, transfer measurement, and job-relevant training. Several new transfer variables also emerged from the data, indicating existing transfer models can be further refined. Ultimately, we propose a refined model of transfer to extend human resource development (HRD) theory in the area of transfer. [source]

    Development and initial validation of an instrument for human capital planning

    Kenneth J. Zula
    This article reports on development and validation of an instrument for use in human capital approaches for organizational planning. The article describes use of a team of subject matter experts in developing a measure of human capital planning, and use of exploratory factor analysis techniques to validate the resulting instrument. These data were obtained from a national survey of 494 human resource management and human resource development respondents. The article presents an instrument for assistance with human capital planning as a strategic human resource management tool and further reports on the initial validity and reliability measures resulting from the analysis. In addition, the usefulness of this instrument for human resource management and human resource development professionals is explored. [source]

    The Spatial Distribution of Threading Dislocations in Gallium Nitride Films

    ADVANCED MATERIALS, Issue 38-39 2009
    Michelle A. Moram
    Spatial analysis techniques are used to study threading dislocations (TDs) at the surfaces of a wide range of GaN films. In all films, the dislocation positions are consistent with a spatially random TD generation process followed by movement of dislocations, but are inconsistent with the spatial distribution of dislocations expected at island coalescence boundaries. [source]

    Understanding and modeling basin hydrology: interpreting the hydrogeological signature

    R. E. Beighley
    Abstract Basin landscapes possess an identifiable spatial structure, fashioned by climate, geology and land use, that affects their hydrologic response. This structure defines a basin's hydrogeological signature and corresponding patterns of runoff and stream chemistry. Interpreting this signature expresses a fundamental understanding of basin hydrology in terms of the dominant hydrologic components: surface, interflow and groundwater runoff. Using spatial analysis techniques, spatially distributed watershed characteristics and measurements of rainfall and runoff, we present an approach for modelling basin hydrology that integrates hydrogeological interpretation and hydrologic response unit concepts, applicable to both new and existing rainfall-runoff models. The benefits of our modelling approach are a clearly defined distribution of dominant runoff form and behaviour, which is useful for interpreting functions of runoff in the recruitment and transport of sediment and other contaminants, and limited over-parameterization. Our methods are illustrated in a case study focused on four watersheds (24 to 50 km2) draining the southern coast of California for the period October 1988 though to September 2002. Based on our hydrogeological interpretation, we present a new rainfall-runoff model developed to simulate both surface and subsurface runoff, where surface runoff is from either urban or rural surfaces and subsurface runoff is either interflow from steep shallow soils or groundwater from bedrock and coarse-textured fan deposits. Our assertions and model results are supported using streamflow data from seven US Geological Survey stream gauges and measured stream silica concentrations from two Santa Barbara Channel,Long Term Ecological Research Project sampling sites. Copyright © 2004 John Wiley & Sons, Ltd. [source]

    Representing elevation uncertainty in runoff modelling and flowpath mapping

    Theodore A. Endreny
    Abstract Vertical inaccuracies in terrain data propagate through dispersal area subroutines to create uncertainties in runoff flowpath predictions. This study documented how terrain error sensitivities in the D8, Multiple Flow (MF), DEMON, D-Infinity and two hybrid dispersal area algorithms, responded to changes in terrain slope and error magnitude. Runoff dispersal areas were generated from convergent and divergent sections of low, medium, and high gradient 64-ha parcels using a 30 m pixel scale control digital elevation model (DEM) and an ensemble of alternative realizations of the control DEM. The ensemble of alternative DEM realizations was generated randomly to represent root mean square error (RMSE) values ranging from 0·5 to 6 m and spatial correlations of 0 to 0·999 across 180 m lag distances. Dispersal area residuals, derived by differencing output from control and ensemble simulations, were used to quantify the spatial consistency of algorithm dispersal area predictions. A maximum average algorithm consistency of 85% was obtained in steep sloping convergent terrain, and two map analysis techniques are recommended in maintaining high spatial consistencies under less optimum terrain conditions. A stochastic procedure was developed to translate DEM error into dispersal area probability maps, and thereby better represent uncertainties in runoff modelling and management. Two uses for these runoff probability maps include watershed management indices that identify the optimal areas for intercepting polluted runoff as well as Monte-Carlo-ready probability distributions that report the cumulative pollution impact of each pixel's downslope dispersal area. Copyright © 2001 John Wiley & Sons, Ltd. [source]

    Psychiatric disorder as a first manifestation of cancer: A 10-year population-based study

    Michael E. Benros
    Abstract To investigate the possibility that psychiatric symptoms could be caused by a yet undetected cancer or be part of a paraneoplastic syndrome, nationwide population-based registers were linked including the Danish Psychiatric Central Register and the Danish Cancer Registry. Data were analysed as a cohort study using survival analysis techniques and incidence rate ratios (IRRs) were used as measures of relative risk. A total of 4,320,623 persons were followed in the 10-year period 1994,2003, resulting in 37,581,600 person-years at risk, 202,144 persons with a first-time psychiatric contact, and 208,995 persons diagnosed with cancer. During the first month after a first-time psychiatric contact, the incidence of all forms of cancer was elevated; IRR: 2.61 (95% CI, 2.31,2.95). Particularly the incidence of brain tumours was elevated; IRR: 18.85 (95% CI, 14.52,24.48), but also the incidence of lung cancer; IRR: 2.98 (95% CI, 2.16,4.12), and especially small-cell lung cancer; IRR: 6.13 (95% CI, 3.39,11.07) was elevated. The elevated IRR for most cancers decreased towards unity within the first 3 months, except for brain tumours, for which the IRR remained significantly elevated during the first 9 months. One of every 63 patients above 50 years of age was diagnosed with malignant cancer within 1 year of first-time psychiatric contact. These results indicate an increased incidence of cancer, especially for brain tumours and small-cell lung cancer, in the first months after a first-time contact to a psychiatric hospital. Clinicians should be aware that first-onset psychiatric symptoms could be a sign of a yet undetected cancer. © 2009 UICC [source]

    A method for acceptability region representation in analogue linear networks

    Francesco Grasso
    Abstract A new simple approach to acceptability region representation in analogue linear circuit design is presented. The proposed method is also able to characterize non-convex and disjoint acceptability regions with low computational effort. In fact, the developed procedure is based on the use of symbolic analysis techniques, which permit one to perform only one simulation of the circuit under consideration, thus reducing the computational efforts. The theoretical basis and the algorithm implementing the technique are presented. A circuital example is also included. Copyright © 2008 John Wiley & Sons, Ltd. [source]

    Use of image analysis techniques for objective quantification of the efficacy of different hair removal methods

    S. Bielfeldt
    In the field of consumer-used cosmetics for hair removal and hair growth reduction, there is a need for improved quantitative methods to enable the evaluation of efficacy and claim support. Optimized study designs and investigated endpoints are lacking to compare the efficacy of standard methods, like shaving or plucking, with new methods and products, such as depilating instruments or hair-growth-reducing cosmetics. Non-invasive image analysis, using a high-performance microscope combined with an optimized image analysis tool, was investigated to assess hair growth. In one step, high-resolution macrophotographs of the legs of female volunteers after shaving and plucking with cold wax were compared to observe short-term hair regrowth. In a second step, images obtained after plucking with cold wax were taken over a long-term period to assess the time, after which depilated hairs reappeared on the skin surface. Using image analysis, parameters like hair length, hair width, and hair projection area were investigated. The projection area was found to be the parameter most independent of possible image artifacts such as irregularities in skin or low contrast due to hair color. Therefore, the hair projection area was the most appropriate parameter to determine the time of hair regrowth. This point of time is suitable to assess the efficacy of different hair removal methods or hair growth reduction treatments by comparing the endpoint after use of the hair removal method to be investigated to the endpoint after simple shaving. The closeness of hair removal and visible signs of skin irritation can be assessed as additional quantitative parameters from the same images. Discomfort and pain rating by the volunteers complete the set of parameters, which are required to benchmark a new hair removal method or hair-growth-reduction treatment. Image analysis combined with high-resolution imaging techniques is a powerful tool to objectively assess parameters like hair length, hair width, and projection area. To achieve reliable data and to reduce well known image-analysis artifacts, it was important to optimize the technical equipment for use on human skin and to improve image analysis by adaptation of the image-processing procedure to the different skin characteristics of individuals, like skin color, hair color, and skin structure. [source]

    Les fards rouges cosmétiques et rituels a base de cinabre et d'ocre de l'époque punique en Tunisie: analyse, identification et caractérisation

    A. Alatrache
    Synopsis Natural antique colorants include mainly red pigments such as cinnabar and ochre. These archeological pigments were used especially as funeral and cosmetic makeup and are a material proof of handicraft activities and exchanges. The identification and characterization of a group of punic colorants, corresponding to samples discovered during excavations at several Tunisian archeological sites (Cartage, Ksour Essef, Kerkouane, Bekalta, Makthar, Bou Arada), were conducted using the least destructive analysis techniques such us scanning electron microscopy coupled to X-ray fluorescence microprobe, direct current plasma emission spectroscopy, atomic absorption spectrometry, Fourier transform infrared spectrometry and X-ray diffraction. Eleven natural red colorants from punic period were subject to this investigation and were compared to contemporary substances. Five colorants were cinnabar and the other six were ochre. Résumé Les colorants antiques naturels comportent principalement les pigments rouges tels que le cinabre et l'ocre. Ces pigments archéologiques ont été utilisés spécialement comme fards funéraires et cosmétiques, qui sont des témoins matériels d'activités artisanales et d'échanges. La caractérisation et l'identification d'un ensemble de colorants puniques correspondant à des échantillons découverts lors des fouilles sur divers sites de Tunisie (Carthage, Ksour Essef, Kerkouane, Bekalta, Makthar, Bou Arada) ont été conduites en employant des techniques d'analyse les moins destructives possibles telles que la microscopie électronique à balayage (MEB) couplée à une microsonde de fluorescence X (XRF), les spectrométries d'émission plasma à courant direct (DCP), d'absorption atomique (SAA) et infrarouge à transformée de Fourier (FTIR) et la diffraction aux rayons X (RX). Onze colorants naturels rouges puniques ont été soumis à l'étude et comparés avec des matières contemporaines. Cinq d'entre eux sont des composés de cinabre, les six autres des ocres. [source]

    Investigation of the temperature oscillations in the cylinder walls of a diesel engine with special reference to the limited cooled case

    C. D. Rakopoulos
    Abstract This work investigates the interesting phenomenon of the temperature (cyclic) oscillations in the combustion chamber walls of a diesel engine. For this purpose, a comprehensive simulation code of the thermodynamic cycle of the engine is developed taking into account both the closed and the open parts of it. The energy and state equations are applied, with appropriate combustion, gas heat transfer, and mass exchange with the atmosphere sub-models, to yield cylinder pressure, local temperatures and heat release histories as well as various performance parameters of the engine. The model is appropriately coupled to a wall periodic conduction model, which uses the gas temperature variation as boundary condition throughout the engine cycle after being treated by Fourier analysis techniques. It is calibrated against measurements, at various load and speed conditions, from an experimental work carried out on a direct injection (DI), naturally aspirated, four-stroke, diesel engine located at the authors' laboratory, which has been reported in detail previously. After gaining confidence into the predictive capabilities of the model, it is used to investigate the phenomenon further, thus providing insight into many interesting aspects of transient engine heat transfer, as far as the influence that engine wall material properties have on the values of cyclic temperature swings. These swings can take prohibitive values causing high wall thermal fatigue, when materials of specific technological interest such as thermal insulators (ceramics) are used, and may lead to deterioration in engine performance. Copyright © 2004 John Wiley & Sons, Ltd. [source]

    Nonlinear simulation of mixers for assessing system-level performance

    Nuno B. Carvalho
    Abstract This article deals with nonlinear simulation methods intended to evaluate the impact of mixer nonidealities on the performance of a wireless system. Behavioral models capable of accurately describing the mixer's nonlinear dynamic features at the system level are currently unavailable. The possibility of using alternative circuit analysis techniques to reach this goal is discussed. After a brief review of existing mixer analysis methods, the focus is directed to the techniques amenable to efficiently handling periodic carriers modulated by complex stochastic signals. In particular, it is shown how multi-envelope transient methods coupled with a three-dimensional harmonic-balance engine can model a nonlinear dynamic mixer excited by a modulated RF signal accompanied by a strong adjacent channel interferer and with a local oscillator corrupted by phase noise. © 2005 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2005. [source]