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Selected AbstractsIssues with recruitment to randomised controlled trials in the drug and alcohol field: a literature review and Australian case studyDRUG AND ALCOHOL REVIEW, Issue 2 2008CLARE L. THOMSON Abstract Issues. The randomised control trial (RCT) is a widely used tool for measuring the effectiveness of health treatments and services. However, subject recruitment is an ongoing challenge for those conducting RCTs and may have a serious impact on the success of the study and the reliability of the outcomes. Approach. In this review we present an examination of the problems and strategies associated with recruitment to RCTs, with particular reference to studies conducted in the drug and alcohol field. A case study of recruitment to an RCT for the treatment of alcohol dependence is presented, supplemented by PubMed, Current Contents and Medline searches to identify relevant publications. Key Findings. The literature suggests that the most common barriers to patient participation involve fears of assignment to placebo treatment, insufficient compensation and poor attendance at initial appointments. Moreover, subject referrals from staff may be a greater problem than reluctance of patients. Referrals are inhibited by complicated entry criteria, time constraints due to busy work schedules or a limited research culture. Implications. Subject recruitment may be promoted by financial reimbursement, close partnerships between research and referral staff; increasing the treatment group ratio in multi-drug trials to minimise randomisation to placebo; addressing negative staff attitudes; and simplifying the referral process. Conclusion. The need for multi-centre sites in Australian drug and alcohol treatment studies is highlighted. [source] Intracardiac Echocardiography in Patients with Pacing and Defibrillating Leads: A Feasibility StudyECHOCARDIOGRAPHY, Issue 6 2008Maria Grazia Bongiorni M.D. Background: Lead extraction, an important and necessary component of treatment for many common device and lead-related complications, is a procedure that can provoke much anxiety in even the most experienced operators given the potentially serious complications. The principal impediment to lead extraction is the body's response to an intravascular foreign body with matrix intravascular neoformation, which causes the lead to adhere to the endocardium or vascular structure, increasing the risk of vascular or myocardial damage with lead removal. Fluoroscopic visualization, the commonly visualization used tool, has several limits in terms of anatomical structures visualization. The aim of this study was to assess the safety and feasibility of intracardiac echocardiography (ICE) in patients undergoing pacing and defibrillating leads before and during a transvenous device removal, and its potential role in detecting intracardiac leads and areas of fibrous adherence. Methods: ICE interrogation was performed in 25 consecutive patients with pacing and defibrillating implantable cardioverter defibrillators (ICD) leads before and during device removal. Results: A programmed ICE analysis was completed in 23 out of 25 patients with excellent resolution, providing a "qualitative-quantitative" information on anatomical structures, cardiac leads, and related areas of fibrous adherence. No ICE-related complications occurred. Conclusions: ICE evaluation is safe and feasible in patients with pacing and defibrillating leads before and during transvenous lead removal, offering an excellent visualization of cardiac leads and related areas of adherence. ICE can assist pacing and ICD lead removal and could improve procedure efficacy and safety. [source] High levels of serum prostate-specific antigen due to PSA producing follicular non-Hodgkin's lymphomaEUROPEAN JOURNAL OF HAEMATOLOGY, Issue 2 2007Jan Jelrik Oosterheert Abstract Objective:, Both carcinoma of the prostate and non-Hodgkin's lymphoma are common in elderly patients. Measurement of serum prostate-specific antigen (PSA) is a frequently used tool to diagnose and monitor prostate carcinoma and is generally specific for diseases of the prostate. Case:, We describe a 68-yr-old patient with voiding difficulties and high PSA levels, but without inflammatory or malignant changes upon multiple transrectal ultrasound guided prostate biopsies. Digital rectal examination was normal. Laboratory showed a strongly elevated PSA level (62 ,g/L, Immulight 2000®; DPC, USA). A CT-scan showed a retroperitoneal process with mass in the right pelvis and infiltration of the bladder wall, suggestive for metastatic prostate carcinoma. Surgical excision of an axillary lymph node set the diagnosis at a stage IV follicular lymphoma, Berard grade I to II in which the majority of neoplastic cells expressed PSA. After lymphoma-specific treatment, there was a positron emission tomography (PET) confirmed complete remission with normal PSA levels (6 ,g/L), which still persists. Conclusion:, Although rare, high PSA levels can be due to the presence of non-Hodgkin's lymphoma. Such a diagnosis should be considered when patients present with lymphadenopathy other than regional prostatic lymphadenopathy. [source] Simultaneous estimation of diffusive Volatile Organic Compound (VOC) fluxes and Non-Aqueous Phase Liquid (NAPL) saturation in the vadose zoneGROUND WATER MONITORING & REMEDIATION, Issue 2 2005David Werner Soil-gas monitoring is a widely used tool to observe the migration of volatile organic compounds (VOCs) at contaminated sites. By combining this technique with natural gradient tracer methods, diffusive contaminant fluxes can be measured in situ, and non,aqueous phase liquid (NAPL) can be detected and roughly quantified. This work describes the new approach and its application at a field site in Denmark with an emplaced NAPL contamination. Soil-gas probes with a low dead volume were installed at 1-m depths in the sandy vadose zone, and a small volume of gas containing conservative and partitioning tracers was injected. Soil-gas samples were withdrawn subsequently during 1 to 4 h and analyzed simultaneously for VOCs and tracers. Tracers detected the NAPL reliably, and the combined data allowed for a close delineation of the source zone. The calculated NAPL saturation deviated by up to a factor of 3 from the analyses of soil cores. Better agreement was found by taking the NAPL composition into consideration, which is, however, generally unknown at the actual field sites. In addition, the tracers were also used to estimate effective diffusion coefficients in situ, which varied by a factor of 2 between various locations. From these data, diffusive contaminant vapor fluxes were quantified without additional laboratory experiments or the use of empirical relationships. The new approach yields a better site investigation with a few additional measurements. [source] Generalized consistency and intensity vectors for comparison matricesINTERNATIONAL JOURNAL OF INTELLIGENT SYSTEMS, Issue 12 2007L. D'Apuzzo A crucial problem in a decision-making process is the determination of a scale of relative importance for a set X = {x1, x2,..., xn} of alternatives either with respect to a criterion C or an expert E. A widely used tool in Multicriteria Decision Making is the pairwise comparison matrix A = (aij), where aij is a positive number expressing how much the alternative xi is preferred to the alternative xj. Under a suitable hypothesis of no indifference and transitivity over the matrix A = (aij), the actual qualitative ranking on the set X is achievable. Then a vector w may represent the actual ranking at two different levels: as an ordinal evaluation vector, or as an intensity vector encoding information about the intensities of the preferences. In this article we focus on the properties of a pairwise comparison matrix A = (aij) linked to the existence of intensity vectors. © 2007 Wiley Periodicals, Inc. Int J Int Syst 22: 1287,1300, 2007. [source] Parallel implementation of AutoDockJOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 3 2007Prashant Khodade Computational docking of ligands to protein structures is a key step in structure-based drug design. Currently, the time required for each docking run is high and thus limits the use of docking in a high-throughput manner, warranting parallelization of docking algorithms. AutoDock, a widely used tool, has been chosen for parallelization. Near-linear increases in speed were observed with 96 processors, reducing the time required for docking ligands to HIV-protease from 81,min, as an example, on a single IBM Power-5 processor (1.65,GHz), to about 1,min on an IBM cluster, with 96 such processors. This implementation would make it feasible to perform virtual ligand screening using AutoDock. [source] Estimating deer abundance from line transect surveys of dung: sika deer in southern ScotlandJOURNAL OF APPLIED ECOLOGY, Issue 2 2001Fernanda F.C. Marques Summary 1Accurate and precise estimates of abundance are required for the development of management regimes for deer populations. In woodland areas, indirect dung count methods, such as the clearance plot and standing crop methods, are currently the preferred procedures to estimate deer abundance. The use of line transect methodology is likely to provide a cost-effective alternative to these methods. 2We outline a methodology based on line transect surveys of deer dung that can be used to obtain deer abundance estimates by geographical block and habitat type. Variance estimation procedures are also described. 3As an example, we applied the method to estimate sika deer Cervus nippon abundance in south Scotland. Estimates of deer defecation and length of time to dung decay were used to convert pellet group density to deer density by geographical block and habitat type. The results obtained agreed with knowledge from cull and sightings data, and the precision of the estimates was generally high. 4Relatively high sika deer densities observed in moorland areas up to 300 m from the forest edge indicated the need to encompass those areas in future surveys to avoid an underestimate of deer abundance in the region of interest. 5It is unlikely that a single method for estimating deer abundance will prove to be better under all circumstances. Direct comparisons between methods are required to evaluate thoroughly the relative merits of each of them. 6Line transect surveys of dung are becoming a widely used tool to aid management and conservation of a wide range of species. The survey methodology we outline is readily adaptable to other vertebrates that are amenable to dung survey methodology. [source] A weak degeneracy revealing decomposition for the CANDECOMP/PARAFAC modelJOURNAL OF CHEMOMETRICS, Issue 2 2010Roberto Rocci Abstract The CANDECOMP/PARAFAC (CP) model is a well known and frequently used tool for extracting substantial information from a three-way data array. It has several useful characteristics and usually gives meaningful insights about the underlying structure of the data. However, in some cases it has a ,strange' behaviour suffering from the so-called ,degenerate solutions', i.e. solutions where the components show a diverging pattern and are meaningless. Several authors have investigated the causes of degeneracy concluding that the phenomenon is due to a lack of minimum of the loss function. In this paper, we study the degeneracy of CP limiting our attention to the two-component case. The study is done by introducing a canonical form, called 2DR, which is ,weakly degeneracy revealing'. On the ground of this framework, degeneracy is studied along with some of the remedies proposed in the literature by using a Tucker3 model having a core in the 2DR form. The analysis gives new insights about the behaviour of the CP model and suggests new ideas on how to deal with degeneracy. Copyright © 2010 John Wiley & Sons, Ltd. [source] Hierarchical Activity Model for Risk-Based Decision MakingJOURNAL OF INDUSTRIAL ECOLOGY, Issue 6 2009Integrating Life Cycle, Plant-Specific Risk Assessments Summary For the practical implementation of the assessment of environmental impact, actual procedures and data requirements should be clarified so that industrial decision makers understand them. Researchers should consider local risks related to processes and environmental impact throughout the life cycle of products simultaneously to supervise these adverse effects appropriately. Life cycle assessment (LCA) is a useful tool for quantifying the potential impact associated with a product life cycle. Risk assessment (RA) is a widely used tool for identifying chemical risks in a specific situation. In this study, we integrate LCA and RA for risk-based decision making by devising a hierarchical activity model using the type-zero method of integrated definition language (IDEF0). The IDEF0 activity modeling language has been applied to connect activities with information flows. Process generation, evaluation, and decision making are logically defined and visualized in the activity model with the required information. The activities, information flows, and their acquisitions are revealed, with a focus on which data should be collected by on-site engineers. A case study is conducted on designing a metal cleaning process reducing chemical risks due to the use of a cleansing agent. LCA and RA are executed and applied effectively on the basis of integrated objective settings and interpretation. The proposed activity model can be used as a foundation to incorporate such assessments into actual business models. [source] The reliability of different formulae to predict creatinine clearanceJOURNAL OF INTERNAL MEDICINE, Issue 5 2003J. C. Verhave Abstract., Verhave JC, Baljé-Volkers CP, Hillege HL, de Zeeuw D, de Jong PE (University Medical Center Groningen, Groningen University, Institute of Drug Exploration, Groningen, the Netherlands). The reliability of different formulae to predict creatinine clearance. J Intern Med 2003; 253: 563,573. Objectives., Creatinine clearance (CCR) is a commonly used tool to measure glomerular filtration rate (GFR) in clinical practice. This tool requires collection of 24-h urine, which is quite bothersome. Several different formulae have been used to estimate GFR using plasma creatinine and other easy formulae to obtain biometrical data. We examined 10 formulae and compared them with actually measured CCR in a large sample of the general population. Design., Cross-sectional cohort study. Setting., University hospital outpatient clinic, a population based study. Subjects., A total of 8592 inhabitants of the city of Groningen, 28,75 years of age. The cohort is enriched for microalbuminuria. Results., In general, the formulae did not give an accurate estimation of CCR, particularly not in male and in obese subjects. Six formulae, including the Cockcroft,Gault gave a fairly good estimation of CCR in the overall population and in subgroups of specific gender, body mass index and age. All formulae however, gave an underestimation of the measured CCR in higher ranges of CCR and an overestimation in the lower ranges. Moreover, the age-related decline of CCR is hard to approximate with a formula. Conclusions., We conclude that formulae to estimate CCR in the general population, although giving a fairly good estimate of mean CCR, do not offer reliable data on CCR in the upper and lower ranges and do not adequately estimate the age,related decline in CCR. [source] Phosphorus L2,3 -edge XANES: overview of reference compoundsJOURNAL OF SYNCHROTRON RADIATION, Issue 2 2009Jens Kruse Synchrotron-based X-ray absorption near-edge structure (XANES) spectroscopy is becoming an increasingly used tool for the element speciation in complex samples. For phosphorus (P) almost all XANES measurements have been carried out at the K -edge. The small number of distinctive features at the P K -edge makes in some cases the identification of different P forms difficult or impossible. As indicated by a few previous studies, the P L2,3 -edge spectra were richer in spectral features than those of the P K -edge. However, experimentally consistent spectra of a wide range of reference compounds have not been published so far. In this study a library of spectral features is presented for a number of mineral P, organic P and P-bearing minerals for fingerprinting identification. Furthermore, the effect of radiation damage is shown for three compounds and measures are proposed to reduce it. The spectra library provided lays a basis for the identification of individual P forms in samples of unknown composition for a variety of scientific areas. [source] Reliable assessment of high temperature oxidation resistance by the development of a comprehensive code of practice for thermocycling oxidation testing , European COTEST project ,MATERIALS AND CORROSION/WERKSTOFFE UND KORROSION, Issue 1 2006M. Schütze Abstract The cyclic oxidation test is the most often used tool in industry to characterise the high temperature oxidation/corrosion resistance of technical materials in the laboratory. In the past, however, there has been the problem of a lack of intercomparability of data from different laboratories and sometimes even from different test runs in the same lab since no general guidelines or standards were existing for this type of test. Being aware of this situation the European COTEST research project was started with 23 participants from 11 countries including representatives from industry, universities, private institutes and national research labs. The present paper reports about the outcome of this project after three years. The project consisted of 8 work packages including literature search on the state-of-the-art at the beginning of the work, experimental investigations supported by a statistics approach in order to quantify the impact of the different test parameters on the test results, a validation testing phase and the development of a comprehensive set of guidelines. The latter is available on the internet and serves as a basis for a future ISO standard for this type of test. [source] Power and sample size for nested analysis of molecular varianceMOLECULAR ECOLOGY, Issue 19 2009BENJAMIN M. FITZPATRICK Abstract Analysis of molecular variance (amova) is a widely used tool for quantifying the contribution of various levels of population structure to patterns of genetic variation. Implementations of amova use permutation tests to evaluate null hypotheses of no population structure within groups and between groups. With few populations per group, between-group structure might be impossible to detect because only a few permutations of the sampled populations are possible. In fact, with fewer than six total populations, permutation tests will never result in P -values <0.05 for higher-level population structure. I present minimum numbers of replicates calculated from multinomial coefficients and an r script that can be used to evaluate the minimum P -value for any sampling scheme. While it might seem counterintuitive that a large sample of individuals is uninformative about hierarchical structure, the power to detect between-group differences depends on the number of populations per group and investigators should sample appropriately. [source] The H-reflex as a tool in neurophysiology: Its limitations and uses in understanding nervous system functionMUSCLE AND NERVE, Issue 2 2003John E. Misiaszek PhD Abstract The Hoffmann reflex (H-reflex) is extensively used as both a research and clinical tool. The ease with which this reflex can be elicited in several muscles throughout the body makes it an attractive tool. This review discusses some of the important limitations in using the H-reflex. In particular, the inaccurate but widely held assumptions that the H-reflex (1) represents the monosynaptic reflex of the Ia afferent onto homonymous motoneurons, and (2) can be used to measure motoneuronal excitability are addressed. The second part of this review explores the utility of the H-reflex as a neural probe in neurophysiology and motor control research. Applications ranging from the investigation of the functional organization of neural circuitry to the study of adaptive plasticity in spinal structures in health and disease suggest that the H-reflex will continue to be an extensively used tool in motor control neurophysiology. Muscle Nerve 28: 144,160, 2003 [source] Changes in the impact factor of anesthesia/critical care journals within the past 10 yearsACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 7 2000J. Boldt Background: The impact factor (IF) is published by the Institute for Scientific Information (ISI). There is a tendency to assess quality of scientific journals with the help of the IF. An analysis of the changes in the IF over time in the different specialities may help to further enlighten the worth and problems of the IF. Methods: The IFs listed under the subheadings Anesthesiology and Emergency Medicine & Critical Care in the Science Citation Index , Journal Citation Report were descriptively analysed over the past 10 years. Additionally, IFs of some other important journals (subheadings Surgery, Cardiovascular, General Medicine) were analysed. Results: The IF of most of the journals showed a constant increase over the years (average in Anesthesiology: +65%; average in Emergency Medicine & Critical Care: +145%). IFs of the highest ranked journals of other specialities showed a similar increase over the years (average in surgical journals: +56%; average in cardiac journals: +59%; average in general journals: +40%). More Anesthesiology and Emergency Medicine & Critical Care journals originated from the USA show an IF >2.0 over the past 10 years than do European journals. Conclusion: Although the value of the IF is highly controversial, it is a frequently used tool to assess rating of a medical journal. Anesthesiology and Emergency Medicine & Critical Care journals showed a continuous increase in the IF over the past 10 years. [source] Magnetic Resonance Imaging and the Female Sexual Response: Overview of Techniques, Results, and Future DirectionsTHE JOURNAL OF SEXUAL MEDICINE, Issue 7 2008Kenneth R. Maravilla ABSTRACT Introduction., Magnetic resonance imaging (MRI) is becoming a frequently used tool in the study of sexual physiology and neurophysiology. Aim., This report reviews various MRI methods used to study the female sexual arousal response. Methods., Retrospective review of pertinent literature. Results., Dynamic genital MRI studies enable the visualization of the physiologic arousal response that provides the direct observation of the time course and magnitude of this response, along with the variability that appears to occur in women with sexual arousal disorder. Functional brain MR studies are described and summarized along with an overview of what we have learned. Finally, the speculation on how we may be able to use MRI technology to better understand the female sexual response and to help in validating new drug treatments or in devising new treatment strategies for sexual dysfunction is also presented. Conclusions., Neuroimaging has already been proven as an invaluable research tool to study the sexual response in women both in the pelvis as well as within the brain. Using these techniques, major inroads are being made to improve the understanding of the sexual arousal process in women. Maravilla KR, and Yang CC. Magnetic resonance imaging and the female sexual response: Overview of techniques, results, and future directions. J Sex Med 2008;5:1559,1571. [source] IS THE REVISED TRAUMA SCORE STILL USEFUL?ANZ JOURNAL OF SURGERY, Issue 11 2003Belinda J. Gabbe The revised trauma score (RTS) has been embraced by the trauma community worldwide. Although originally developed as a triage tool, the use of the RTS has since been expanded to include the prediction of outcome following traumatic injury. Through a critical review of the literature, evidence for use of the RTS is discussed along with the limitations of this commonly used tool. In summary, the RTS is a well-established predictor of mortality in trauma populations, but there is a lack of definitive evidence supporting its use as a primary triage tool and as a predictor of outcomes other than mortality. Difficulty in collecting the components of the RTS creates issues for data validity and the use of the RTS as a research tool. Although the weighted RTS has been developed to improve the prediction capacity of the RTS, studies reporting its use are few and there is debate regarding the applicability of the published coefficients for broad use. Overall, further studies are warranted to clearly establish the usefulness of the RTS as a triage tool in the field, to further evaluate the weighted version of the RTS, and to determine the ability of the RTS to predict functional outcome and quality of life. In particular, future research is needed to address these issues in Australian trauma populations. [source] Doppler tomography of accretion in binariesASTRONOMISCHE NACHRICHTEN, Issue 3 2004Article first published online: 3 MAR 200, D. Steeghs Abstract Since its conception, Doppler tomography has matured into a versatile and widely used tool. It exploits the information contained in the highly-structured spectral line-profiles typically observed in mass-transferring binaries. Using inversion techniques akin to medical imaging, it permits the reconstruction of Doppler maps that image the accretion flow on micro-arcsecond scales. I summarise the basic concepts behind the technique and highlight two recent results; the use of donor star emission as a means to system parameter determination, and the real-time movies of the evolving accretion flow in the cataclysmic variable WZ Sge during its 2001 outburst. I conclude with future opportunities in Doppler tomography by exploiting the combination of superior data sets, second generation reconstruction codes and simulated theoretical tomograms to delve deeper into the physics of accretion flows. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Highly Fluorescent Conjugated Pyrenes in Nucleic Acid Probes: (Phenylethynyl)pyrenecarbonyl-Functionalized Locked Nucleic AcidsCHEMISTRY - A EUROPEAN JOURNAL, Issue 35 2008Irina Abstract In recent years, fluorescently labeled oligonucleotides have become a widely used tool in diagnostics, DNA sequencing, and nanotechnology. The recently developed (phenylethynyl)pyrenes are attractive dyes for nucleic acid labeling, with the advantages of long-wave emission relative to the parent pyrene, high fluorescence quantum yields, and the ability to form excimers. Herein, the synthesis of six (phenylethynyl)pyrene-functionalized locked nucleic acid (LNA) monomers M1,M6 and their incorporation into DNA oligomers is described. Multilabeled duplexes display higher thermal stabilities than singly modified analogues. An increase in the number of phenylethynyl substituents attached to the pyrene results in decreased binding affinity towards complementary DNA and RNA and remarkable bathochromic shifts of absorption/emission maxima relative to the parent pyrene fluorochrome. This bathochromic shift leads to the bright fluorescence colors of the probes, which differ drastically from the blue emission of unsubstituted pyrene. The formation of intra- and interstrand excimers was observed for duplexes that have monomers M1,M6 in both complementary strands and in numerous single-stranded probes. If more phenylethynyl groups are inserted, the detected excimer signals become more intense. In addition, (phenylethynyl)pyrenecarbonyl,LNA monomers M4, M5, and M6 proved highly useful for the detection of single mismatches in DNA/RNA targets. [source] The Andersen thermostat in molecular dynamicsCOMMUNICATIONS ON PURE & APPLIED MATHEMATICS, Issue 1 2008Weinan E We carry out a mathematical study of the Andersen thermostat [1], which is a frequently used tool in molecular dynamics. After reformulating the continuous- and discrete-time Andersen dynamics, we prove that in both cases the Andersen dynamics is uniformly ergodic. A detailed numerical analysis is presented, establishing the rate of convergence of most commonly used numerical algorithms for the Andersen thermostat. Transport properties such as the diffusion constant are also investigated. It is proved for the Lorentz gas model where there is intrinsic diffusion that the diffusion coefficient calculated using the Andersen thermostat converges to the true diffusion coefficient in the limit of vanishing collision frequency in the Andersen thermostat. © 2007 Wiley Periodicals, Inc. [source] Review of quality of life: menorrhagia in women with or without inherited bleeding disordersHAEMOPHILIA, Issue 1 2008M. SHANKAR Summary., The objectives of this study were to identify the impact of menorrhagia on the health-related quality of life (HRQOL) of women in general and those with inherited bleeding disorders and to identify the commonly used tools in assessing quality of life. A review of studies evaluating quality of life in women suffering from menorrhagia was conducted. Data sources used included electronic databases Medline and Embase. Reference lists and bibliographies of the relevant papers and books were hand-searched for additional studies. Eighteen of the 53 studies identified measured quality of life prior to treatment of menorrhagia. Ten of the studies used a validated measure of quality of life. Five studies involving a total of 1171 women with menorrhagia in general and using SF-36 were considered for further review. The mean SF-36 scores in women with menorrhagia were worse in all the eight scales when compared with normative scores from a general population of women. Three studies, involving 187 women, assessed the quality of life in women with menorrhagia and inherited bleeding disorders. None of these studies used a validated HRQOL score making it difficult for comparison. However, all reported poorer scores in study women compared to the controls. In conclusion, HRQOL is adversely affected in women with menorrhagia in general and in those with inherited bleeding disorders. HRQOL evaluation is useful in the management of women with menorrhagia for assessment of treatment efficacy. [source] Optimizing the tuning parameters of least squares support vector machines regression for NIR spectraJOURNAL OF CHEMOMETRICS, Issue 5 2006T. Coen Abstract Partial least squares (PLS) is one of the most used tools in chemometrics. Other data analysis techniques such as artificial neural networks and least squares support vector machines (LS-SVMs) have however made their entry in the field of chemometrics. These techniques can also model nonlinear relations, but the presence of tuning parameters is a serious drawback. These parameters balance the risk of overfitting with the possibility to model the underlying nonlinear relation. In this work a methodology is proposed to initialize and optimize those tuning parameters for LS-SVMs with radial basis function (RBF)-kernel based on a statistical interpretation. In this way, these methods become much more appealing for new users. The presented methods are applied on manure spectra. Although this dataset is only slightly nonlinear, good results were obtained. Copyright © 2007 John Wiley & Sons, Ltd. [source] Clinical use of physical activity measuresJOURNAL OF THE AMERICAN ACADEMY OF NURSE PRACTITIONERS, Issue 2 2009CRNP (Associate Professor), Lorraine M Reiser PhD Abstract Purpose:, To provide a review of physical activity measures and subjective and objective methods of its measurement. Considerations for the use of these measurements in research and practice will be discussed. Data sources:, The PubMed, CINAHL, and Health and Psychosocial Instruments databases, and the Centers for Disease Control Web site were searched using the search term "Physical Activity Measurement." Conclusions:, Physical activity is a lifestyle factor that is a key focus in chronic disease,related research, prevention, and interventions. Healthy People 2010 set goals of decreasing the prevalence of preventable diseases by encouraging healthier lifestyle patterns. Shifts toward more sedentary lifestyles have resulted in increases in life-limiting disease states, including obesity, diabetes, heart disease, cancer, and osteoporosis. Physical activity measurements have been used widely in research studies but are less commonly used in primary care. Measuring individuals' physical activity levels as part of the health assessment will enhance the provider's ability to engage in health promotion and suggest health protection interventions. The strengths, weaknesses, and potential applications to practice of physical activity measures are summarized in an effort to familiarize nurse practitioners (NPs) with commonly used tools and encourage integration of physical activity assessment into their current practice. Implications for practice:, NPs are in an ideal position to promote health by encouraging appropriate amounts of physical activity. Screening, health promotion, and disease prevention are part of the core competencies of NP practice established by the National Organization of Nurse Practitioner Faculties. Increased knowledge of physical activity measures will enhance the NP's ability to evaluate relevant physical activity research for use in evidence-based practice. Incorporation of simple yet appropriate physical activity measurements into practice will expand the NP's ability to identify and thus address sedentary lifestyles in their clientele. [source] On the analysis of long-term experimentsJOURNAL OF THE ROYAL STATISTICAL SOCIETY: SERIES A (STATISTICS IN SOCIETY), Issue 1 2007Thomas M. Loughin Summary., Long-term experiments are commonly used tools in agronomy, soil science and other disciplines for comparing the effects of different treatment regimes over an extended length of time. Periodic measurements, typically annual, are taken on experimental units and are often analysed by using customary tools and models for repeated measures. These models contain nothing that accounts for the random environmental variations that typically affect all experimental units simultaneously and can alter treatment effects. This added variability can dominate that from all other sources and can adversely influence the results of a statistical analysis and interfere with its interpretation. The effect that this has on the standard repeated measures analysis is quantified by using an alternative model that allows for random variations over time. This model, however, is not useful for analysis because the random effects are confounded with fixed effects that are already in the repeated measures model. Possible solutions are reviewed and recommendations are made for improving statistical analysis and interpretation in the presence of these extra random variations. [source] Retrograde tracing of enteric neuronal pathwaysNEUROGASTROENTEROLOGY & MOTILITY, Issue 1 2001S. J. H. Brookes Neuroanatomical tracing techniques, and retrograde labelling in particular, are widely used tools for the analysis of neuronal pathways in the central and peripheral nervous system. Over the last 10 years, these techniques have been used extensively to identify enteric neuronal pathways. In combination with multiple-labelling immunohistochemistry, quantitative data about the projections and neurochemical profile of many functional classes of cells have been acquired. These data have revealed a high degree of organization of the neuronal plexuses, even though the different classes of nerve cell bodies appear to be randomly assorted in ganglia. Each class of neurone has a predictable target, length and polarity of axonal projection, a particular combination of neurochemicals in its cell body and distinctive morphological characteristics. The combination of retrograde labelling with targeted intracellular recording has made it possible to target small populations of cells that would rarely be sampled during random impalements. These neuroanatomical techniques have also been applied successfully to human tissue and are gradually unravelling the complexity of the human enteric nervous system. [source] The Use of an Exact Light-Scattering Theory for Spheroidal TiO2 Pigment ParticlesPARTICLE & PARTICLE SYSTEMS CHARACTERIZATION, Issue 2 2006Juho-Pertti Jalava Abstract Titanium dioxide pigments are widely used, e.g., in paints, printing inks, plastics, and papers, because of the excellent and whiteness they provide. As is well known, the opacity and to it related optical properties depend on the pigment's crystal- and particle-size distributions (CSD, PSD). Therefore, the process and quality control of the CSD and PSD are very essential. The development of a straightforward and sophisticated method for process and quality control is presented here. The principal component is a new determination method for the PSD based on an accurate theory of light scattering of spheroidal particles. In this new method, called the turbidity spectrum method (TSM), the whole turbidity spectrum is measured. This spectrum, which is due to the particle-size distribution of the pigment particles, is then solved using the T-matrix method by taking into account the shape of the particles. After that the CSD is extracted from the PSD. The T-matrix method is one of the most powerful and widely used tools for the rigorous computing of electromagnetic scattering by non-spherical particles. The repeatability of the mean PSD (,200,nm) obtained by the TSM is excellent, with a standard deviation of 0.1,nm (0.05,%). Linear regression models based on TSM results were developed for undertone and tint-reducing power, which are important optical parameters of the pigment. The excellent repeatability of the TSM results was necessary for the production of representative models. [source] Conformal transformations and conformal invariance in gravitationANNALEN DER PHYSIK, Issue 1 2009M.P. Da, browski Abstract Conformal transformations are frequently used tools in order to study relations between various theories of gravity and Einstein's general relativity theory. In this paper we discuss the rules of these transformations for geometric quantities as well as for the matter energy-momentum tensor. We show the subtlety of the matter energy-momentum conservation law which refers to the fact that the conformal transformation "creates" an extra matter term composed of the conformal factor which enters the conservation law. In an extreme case of the flat original spacetime the matter is "created" due to work done by the conformal transformation to bend the spacetime which was originally flat. We discuss how to construct the conformally invariant gravity theories and also find the conformal transformation rules for the curvature invariants R2, RabRab, RabcdRabcd and the Gauss-Bonnet invariant in a spacetime of an arbitrary dimension. Finally, we present the conformal transformation rules in the fashion of the duality transformations of the superstring theory. In such a case the transitions between conformal frames reduce to a simple change of the sign of a redefined conformal factor. [source] | ||||||||||||||||||||||||||||