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Empirical Methods (empirical + methods)
Selected AbstractsDancing with the Devil: Partnering with Industry but Publishing in Academia,DECISION SCIENCES, Issue 4 2007V. Daniel R. Guide Jr ABSTRACT We believe that partnering with industry can lead to research that is relevant, rigorous, and refreshing. Our experiences show that the potential benefits of partnering with industry are enormous, but that this is not an easy route for academics interested in operations research modeling or empirical methods. The need for grounded business research is greater now than ever, and, while academics have made great progress, there are still numerous opportunities to demonstrate the relevance of our research. We discuss how to establish industry contacts, identify fruitful academic,industry projects, and publish the resulting research. [source] Panic disorder phenomenology in urban self-identified caucasian,non-hispanics and caucasian,hispanicsDEPRESSION AND ANXIETY, Issue 1 2003Michael Hollifield M.D. Abstract The epidemiology of panic disorder is well known, but data about some phenomenological aspects are sparse. The symptom criteria for panic disorder were developed largely from rational expert consensus methods and not from empirical research. This fact calls attention to the construct validity of the panic disorder diagnosis, which may affect accuracy of epidemiological findings. Seventy self-identified Non-Hispanic,Caucasian (Anglo) and Hispanic,Caucasian (Hispanic) people who were diagnosed with DSM-III-R panic disorder with or without agoraphobia were invited to complete a Panic Phenomenological Questionnaire (PPQ), which was constructed for this study from the Hamilton Anxiety Scale Items and The DSM-III-R panic symptoms. Fifty (71%) subjects agreed to participate, and there was no response bias detected. Seven symptoms on the PPQ that are not in the DSM-IV diagnostic criteria were reported to occur with a high prevalence in this study. Furthermore, many symptoms that occurred with a high frequency and were reported to be experienced as severe are also not included in current nosology. A few of the DSM-IV criterion symptoms occurred with low prevalence, frequency, and severity. Cognitive symptoms were reported to occur with higher frequency and severity during attacks than autonomic or other symptoms. There were modest differences between ethnic groups with regard to panic attack phenomena. Further research using multiple empirical methods aimed at improving the content validity of the panic disorder diagnosis is warranted. This includes utilizing consistent methods to collect data that will allow for rational decisions about how to construct valid panic disorder criteria across cultures. Depression and Anxiety 18:7,17, 2003. © 2003 Wiley-Liss, Inc. [source] A Bayesian hierarchical model for over-dispersed count data: a case study for abundance of hake recruitsENVIRONMETRICS, Issue 1 2007Jorge M. Mendes Abstract In this paper, we introduce a Bayesian Hierarchical model to estimate the abundance of hake recruits, as well as to study their spatial distributional patterns in the Portuguese territorial waters. Main objective of the paper is to improve on traditional empirical methods based on sampling averages and variances by using probabilistic models that capture spatial dependence structures. Copyright © 2006 John Wiley & Sons, Ltd. [source] Numerical investigation of the effectiveness of a bored pile wall for the minimisation of settlement resulting from tunnel driving.GEOMECHANICS AND TUNNELLING, Issue 6 2009Numerische Untersuchung der Wirkungsweise einer Bohrpfahlwand zur Minimierung der Setzungen infolge Tunnel Soil mechanics; Innovative procedures; Bodenmechanik; Neue Verfahren Abstract Bored pile walls can be constructed between buildings and tunnel alignments to protect sensitive buildings from settlement resulting from tunnelling. The aim of the research work presented here was to evaluate the effectiveness of such a bored pile wall with FE calculations and identify influential parameters. Two methods of predicting settlement were investigated with the programme ABAQUS: The GAP method, where the deformations of the tunnel contour are prescribed, and the stress reduction method, with which the support pressure at the tunnel contour is reduced. The ground is modelled as linear-elastic, ideal-plastic with a Mohr-Coulomb failure criterion as well as with a hypoplastic constitutive law. The contact surface between wall and ground was modelled with complete bonding as well as with a contact law with friction. The simulation results with the stress reduction method and the hypoplastic material model show the best results qualitatively. The predict settlements agree well with empirical methods and centrifuge tests from the literature. The simulations show that the effectiveness of the wall is significantly influenced by the contact properties in the boundary surface. It achieves the best protection effect when frictionless. Zur Abschirmung sensibler Gebäude vor Setzungen infolge Tunnelvortrieb können Bohrpfahlwände zwischen Gebäude und Tunneltrasse eingesetzt werden. Ziel der hier präsentierten Forschungsarbeit war es, die Wirksamkeit einer solchen Bohrpfahlwand mit FE-Berechnungen nachzuvollziehen und Einflussparameter zu identifizieren. Mit dem Programm ABAQUS wurden zwei Möglichkeiten zur Setzungsprognose untersucht: Die GAPMethode, bei der die Verschiebungen der Tunnelkontur vorgegeben werden, und die Spannungsreduktions-Methode, bei welcher der Stützdruck an der Tunnelkontur reduziert wird. Der Boden wurde als linear-elastisch, ideal-plastisch mit Grenzbedingung nach Mohr-Coulomb sowie mit einem hypoplastischen Stoffgesetz modelliert. Die Kontaktfläche zwischen Wand und Boden wurde sowohl mit vollständigem Verbund als auch mit einem Kontaktgesetz mit Reibung modelliert. Die Simulationsergebnisse mit der Spannungsreduktions-Methode und dem hypoplastischen Materialmodell zeigen die qualitativ besten Ergebnisse. Die Setzungsprognosen stimmen gut mit empirischen Ansätzen und Zentrifugenversuchen aus der Literatur überein. Die Simulationen veranschaulichen, dass die Wirksamkeit der Wand maßgeblich von den Kontakteigenschaften in der Grenzfläche beeinflusst wird. Die größte Abschirmwirkung erzielt sie bei Reibungsfreiheit. [source] Downscaling of global climate models for flood frequency analysis: where are we now?HYDROLOGICAL PROCESSES, Issue 6 2002Christel Prudhomme Abstract The issues of downscaling the results from global climate models (GCMs) to a scale relevant for hydrological impact studies are examined. GCM outputs, typically at a spatial resolution of around 3° latitude and 4° longitude, are currently not considered reliable at time scales shorter than 1 month. Continuous rainfall-runoff modelling for flood regime assessment requires input at the daily or even hourly time-step. A review of the different methodologies suggested in the literature to downscale GCM results at smaller spatial and temporal resolutions is presented. The methods, from simple interpolation to more sophisticated dynamical modelling, through multiple regression and weather generators, are, however, mostly based directly on GCM outputs, sometimes at daily time-step. The approach adopted is a simple, empirical methodology based on modelled monthly changes from the HadCM2 greenhouse gases experiment for the time horizon 2050s. Three daily rainfall scenarios are derived from the same set of monthly changes, representing different possible changes in the rainfall regime. The first scenario represents an increase of the occurrence of frontal systems, corresponding to a decrease in the rainfall intensity; the second corresponds to an increase in convective storm-type rainfall, characterized by extreme events with higher intensity; the third one assumes an increase in the monthly rainfall without any change in rainfall variability. A continuous daily rainfall-runoff model, calibrated for the Severn catchment, was used to generate daily flow series for the 1961,90 baseline period and the 2050s, and a peaks-over-threshold analysis was undertaken to produce flood frequency distributions for the two time horizons. Though the three scenarios lead to an increase in the magnitude and the frequency of the extreme flood events, the impact is strongly influenced by the type of daily rainfall scenario applied. We conclude that if the next generation of GCMs produce more reliable rainfall variance estimates, then more appropriate ways of deriving rainfall scenarios could be developed using weather generators rather than empirical methods. Copyright © 2002 John Wiley & Sons, Ltd. [source] Plastic energy dissipation and its role on heating/melting of single-component polymers and multi-component polymer blendsADVANCES IN POLYMER TECHNOLOGY, Issue 2 2003Bainian Qian Abstract Plastic energy dissipation (PED) of polymer particulates is, essentially, the energy dissipated during large and repeated plastic deformations of compacted polymer particulates while still in the solid state. PED is higher or much higher than VED, the viscous energy dissipation source of polymeric melts, because the stresses necessary to plastically deform viscoelastic polymer solids are orders of magnitude higher than the stresses needed to support viscous flow. In the last few years our group has demonstrated experimentally the dominant role which PED plays in the heating/melting of solid polymer (compacted) particulate beds in compounding processing equipment, such as twin-screw extruders and counterrotating continuous mixers/melters, in which the deformation of solid polymers is mandatory. We have also developed simple empirical methods of predicting the total axial distance needed for melting a given polymer in specific processing/compounding machines and processing. conditions, as well as the melting rates, all based on the mechanical energy dissipated during solid particulate compression. This work explores the more complex issue of how the PED behavior of single-component polymers may affect the PED (and the heating/melting) behavior of multi-component polymer blends. © 2003 Wiley Periodicals, Inc. Adv Polym Techn 22: 85,95, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.10039 [source] An error corrected almost ideal demand system for major cereals in KenyaAGRICULTURAL ECONOMICS, Issue 1 2010Jonathan M. Nzuma Error correction model; AIDS; Cereal consumption; Kenya Abstract Despite significant progress in theory and empirical methods, the analysis of food consumption patterns in developing countries, particularly those in Sub-Saharan Africa (SSA), has received very limited attention. An attempt is made in this article to estimate an Error Corrected Almost Ideal Demand System for four major cereals consumed in Kenya employing annual data from 1963 to 2005. This demand system performs well on both theoretical and empirical grounds. The symmetry and homogeneity conditions are supported by the data and the,Le Chatelier,principle holds. Empirically, all own-price elasticities are negative and significant at 5% level and irrespective of the time horizon, maize, wheat, rice, and sorghum may be considered as necessities in Kenya. While the expenditure elasticities of all four cereals are positive, they are inelastic both in the short run and in the long run. Finally, wheat and rice complement maize consumption in Kenya while sorghum acts as a substitute. Since cereal consumers have price and income inelastic responses, a combination of income and price-oriented policies could improve cereal consumption in Kenya. [source] An empirical study of the influence of departmentalization and organizational position on software maintenanceJOURNAL OF SOFTWARE MAINTENANCE AND EVOLUTION: RESEARCH AND PRACTICE, Issue 1 2002Dowming Yeh Abstract Differences between software development and maintenance imply that software maintenance work should be measured and managed somewhat differently from software development. On the other hand, maintenance programmers frequently perform the same tasks as development programmers do. How to departmentalize maintenance and development is thus becoming an issue. Departmentalization in software development and maintenance can be classified into two categories, maintenance separated from development and maintenance jointly with development. Departmentalization has its strengths and weaknesses. In this work, quantitative empirical methods are applied to investigate the influence of departmentalization on fulfillment opportunity, time allocations of activities, problem occurrences, and management process in software maintenance. Seven hypotheses are formed and tested by statistical methods. The result shows that separate organizations demonstrate specialization in software maintenance, but managerial attitudes also aggravate the potential status difference for such organizations. Other major pitfalls for departmentalization are also identified. Copyright © 2002 John Wiley & Sons, Ltd. [source] Role of drug metabolism in drug discovery and developmentMEDICINAL RESEARCH REVIEWS, Issue 5 2001Gondi N. Kumar Abstract Metabolism by the host organism is one of the most important determinants of the pharmacokinetic profile of a drug. High metabolic lability usually leads to poor bioavailability and high clearance. Formation of active or toxic metabolites will have an impact on the pharmacological and toxicological outcomes. There is also potential for drug,drug interactions with coadministered drugs due to inhibition and/or induction of drug metabolism pathways. Hence, optimization of the metabolic liability and drug,drug interaction potential of the new chemical entities are some of the most important steps during the drug discovery process. The rate and site(s) of metabolism of new chemical entities by drug metabolizing enzymes are amenable to modulation by appropriate structural changes. Similarly, the potential for drug,drug interactions can also be minimized by appropriate structural modifications to the drug candidate. However, the optimization of the metabolic stability and drug,drug interaction potential during drug discovery stage has been largely by empirical methods and by trial and error. Recently, a lot of effort has been applied to develop predictive methods to aid the optimization process during drug discovery and development. This article reviews the role of drug metabolism in drug discovery and development. © 2001 John Wiley & Sons, Inc. Med Res Rev, 21, No. 5, 397,411, 2001 [source] The Absorption Hypothesis: Learning to Hear God in Evangelical ChristianityAMERICAN ANTHROPOLOGIST, Issue 1 2010T. M. Luhrmann ABSTRACT, In this article, we use a combination of ethnographic data and empirical methods to identify a process called "absorption," which may be involved in contemporary Christian evangelical prayer practice (and in the practices of other religions). The ethnographer worked with an interdisciplinary team to identify people with a proclivity for "absorption." Those who seemed to have this proclivity were more likely to report sharper mental images, greater focus, and more unusual spiritual experience. The more they prayed, the more likely they were to have these experiences and to embrace fully the local representation of God. Our results emphasize learning, a social process to which individuals respond in variable ways, and they suggest that interpretation, proclivity, and practice are all important in understanding religious experience. This approach builds on but differs from the approach to religion within the culture-and-cognition school. [source] Oyster greening by outdoor mass culture of the diatom Haslea ostrearia Simonsen in enriched seawaterAQUACULTURE RESEARCH, Issue 10 2001V Turpin Abstract Oyster greening was first described in the seventeenth century as a natural phenomenon. However, it has recently been discovered that the diatom Haslea ostrearia Simonsen causes greening by synthesis of a blue pigment designated as ,marennine'. This phenomenon, which involves massive proliferation of H. ostrearia in oyster ponds, was not understood or controlled by oyster farmers in the Marennes-Oléron region (Atlantic coast of France). As greening oysters improved their market value, they tried to develop empirical methods to guarantee oyster fattening and improve profits. In this context, the present study investigated the feasibility of mass culture of diatoms outdoors in 10-m3 ponds, using enriched seawater. Different biotic and abiotic parameters were monitored daily to determine the influence of the day,night temperature range. After 8 days, H. ostrearia was the dominant diatom species (66%), reaching a mean cell concentration of 2 × 105 cell mL,1 and a marennine concentration of 3.4 mg L,1. Although intensive greening was obtained, further studies are required to optimize the production stages before this technology can be transferred to oyster farmers. [source] Small area population disease burdenAUSTRALIAN AND NEW ZEALAND JOURNAL OF PUBLIC HEALTH, Issue 4 2001Richard Taylor Small area health statistics has assumed increasing importance as the focus of population and public health moves to a more individualised approach of smaller area populations. Small populations and low event occurrence produce difficulties in interpretation and require appropriate statistical methods, including for age adjustment. There are also statistical questions related to multiple comparisons. Privacy and confidentiality issues include the possibility of revealing information on individuals or health care providers by fine cross-tabulations. Interpretation of small area population differences in health status requires consideration of migrant and Indigenous composition, socio-economic status and rural-urban geography before assessment of the effects of physical environmental exposure and services and interventions. Burden of disease studies produce a single measure for morbidity and mortality-disability adjusted life year (DALY)-which is the sum of the years of life lost (YLL) from premature mortality and the years lived with disability (YLD) for particular diseases (or all conditions). Calculation of YLD requires estimates of disease incidence (and complications) and duration, and weighting by severity. These procedures often mean problematic assumptions, as does future discounting and age weighting of both YLL and YLD. Evaluation of the Victorian small area population disease burden study presents important cross-disciplinary challenges as it relies heavily on synthetic approaches of demography and economics rather than on the empirical methods of epidemiology. Both empirical and synthetic methods are used to compute small area mortality and morbidity, disease burden, and then attribution to risk factors. Readers need to examine the methodology and assumptions carefully before accepting the results. [source] Determination of absolute configurations by X-ray crystallography and 1H NMR anisotropyCHIRALITY, Issue 5 2008Nobuyuki Harada Abstract To determine the absolute configurations of chiral compounds, many spectroscopic and diffraction methods have been developed. Among them, X-ray crystallographic Bijvoet method, CD exciton chirality method, and the combination of vibrational circular dichroism and quantum mechanical calculations are of nonempirical nature. On the other hand, X-ray crystallography using a chiral internal reference, and 1H NMR spectroscopy using chiral anisotropy reagents are relative and/or empirical methods. In addition to absolute configurational determinations, preparations of enantiopure compounds are strongly desired. As chiral reagents useful for both the preparation of enantiopure compounds by HPLC separation and the simultaneous determination of their absolute configurations, we have developed camphorsultam dichlorophthalic acid (CSDP acid) for X-ray crystallography and 2-methoxy-2-(1-naphthyl)propionic acid (M,NP acid) for 1H NMR spectroscopy. In this review, the principles and applications of these X-ray and NMR methods are explained using mostly our own data. Chirality, 2008. © 2007 Wiley-Liss, Inc. [source] | |||||||||||||||||||