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Hierarchical Approach (hierarchical + approach)
Selected AbstractsA Freshwater Classification Approach for Biodiversity Conservation PlanningCONSERVATION BIOLOGY, Issue 2 2005JONATHAN V. HIGGINS biodiversidad de agua dulce; clasificación; planificación de conservación; representativo Abstract:,Freshwater biodiversity is highly endangered and faces increasing threats worldwide. To be complete, regional plans that identify critical areas for conservation must capture representative components of freshwater biodiversity as well as rare and endangered species. We present a spatially hierarchical approach to classify freshwater systems to create a coarse filter to capture representative freshwater biodiversity in regional conservation plans. The classification framework has four levels that we described using abiotic factors within a zoogeographic context and mapped in a geographic information system. Methods to classify and map units are flexible and can be automated where high-quality spatial data exist, or can be manually developed where such data are not available. Products include a spatially comprehensive inventory of mapped and classified units that can be used remotely to characterize regional patterns of aquatic ecosystems. We provide examples of classification procedures in data-rich and data-poor regions from the Columbia River Basin in the Pacific Northwest of North America and the upper Paraguay River in central South America. The approach, which has been applied in North, Central, and South America, provides a relatively rapid and pragmatic way to account for representative freshwater biodiversity at scales appropriate to regional assessments. Resumen:,La biodiversidad de agua dulce está en peligro y enfrenta amenazas crecientes en todo el mundo. Para ser completos, los planes regionales que identifican áreas críticas para la conservación deben incluir componentes representativos de la biodiversidad de agua dulce así como especies raras y en peligro. Presentamos un método espacialmente jerárquico para clasificar sistemas de agua dulce para crear un filtro grueso que capte a la biodiversidad de agua dulce en los planes regionales de conservación. La estructura de la clasificación tiene cuatro niveles que describimos utilizando factores abióticos en un contexto zoogeográfico y localizamos en un sistema de información geográfico. Los métodos para clasificar y trazar mapas son flexibles y pueden ser automatizados, donde existen datos espaciales de alta calidad, o desarrollados manualmente cuando tales datos no están disponibles. Los productos incluyen un inventario completo de unidades mapeadas y clasificadas que pueden ser usadas remotamente para caracterizar patrones regionales de ecosistemas acuáticos. Proporcionamos ejemplos de procedimientos de clasificación en regiones ricas y pobres en datos en la cuenca del Río Columbia en el noroeste de Norte América y del Río Paraguay en Sudamérica central. El método, que ha sido aplicado en Norte, Centro y Sudamérica, proporciona una forma relativamente rápida y pragmática de contabilizar biodiversidad de agua dulce representativa en escalas adecuadas para evaluaciones regionales. [source] Sustainable development indicators for the transmission system of an electric utilityCORPORATE SOCIAL RESPONSIBILITY AND ENVIRONMENTAL MANAGEMENT, Issue 3 2007Cory Searcy Abstract This paper presents a system of sustainable development indicators for the transmission system of a Canadian electric utility. The indicators were developed based on extensive consultations with internal experts at the case utility and external experts in the field of sustainable development indicators. A total of 98 indicators were incorporated into the system, with 70 being developed as a part of this process and 28 representing indicators previously developed by the company. Recognizing the difficulty of working with nearly 100 unstructured measures, four techniques were used to increase the utility of the indicators: (1) the indicators were clustered around eight key priority areas, (2) the indicators were organized according to a hierarchical approach linked to the business planning process, (3) the process of integrating the indicators with existing corporate initiatives was staggered over time and (4) a tiered aggregate was developed. The process of developing the indicators is discussed, with key lessons learned emphasized throughout the paper. Copyright © 2006 John Wiley & Sons, Ltd and ERP Environment. [source] Dose-related effects following oral exposure of 2,4-dinitrotoluene on the western fence lizard, Sceloporus occidentalisENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 2 2008Jamie G. Suski Abstract 2,4-dintitrotoluene (2,4-DNT) is an explosive frequently found in the soil of military installations. Because reptiles can be common on these sites, ecological risk assessments for compounds such as 2,4-DNT could be improved with toxicity data specific to reptiles. Western fence lizards, Sceloporus occidentalis, were used to develop a laboratory toxicity model for reptiles. A hierarchical approach was used; acute to subchronic studies were conducted to provide toxicity data relevant to short- and long-term exposures. First, a modified median lethal dose (LD50) study was conducted on male and female lizards using a stage-wise probit model. The LD50 was 577 mg/kg for female and 380 mg/kg for male lizards. Subsequently, a subacute experiment was conducted to further assess 2,4-DNT toxicity to male lizards and to define exposure levels for a longer term, subchronic study. The subchronic study was conducted for 60 consecutive days; male lizards were exposed to 0, 9, 15, 25, 42, 70 mg/kg/d. Dose-dependent mortality was observed in the three highest dose groups (25, 42, and 70 mg/kg/d); all other animals survived the study duration. Benchmark dose model calculations based on mortality indicated a 5% effect level of 15.8 mg/kg/d. At study termination, a gross necropsy was performed, organ weights were taken, and blood was collected for clinical and hematological analysis. Body weight, kidney weight, food consumption, postdose observations, and blood chemistries all were found to be significantly different from controls at doses above 9 mg/kg/d. Also, preliminary results suggest behavioral observations, and reduced food consumption may be a sensitive indicator of toxicity. The present study indicates Sceloporus occidentalis is suitable for evaluating toxicity of compounds to reptilian species. [source] Potential effects of herbicides on native amphibians: A hierarchical approach to ecotoxicology research and risk assessmentENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 4 2004Dean G. Thompson No abstract is available for this article. [source] An Empirically Based Implementation and Evaluation of a Hierarchical Model for Commuting FlowsGEOGRAPHICAL ANALYSIS, Issue 3 2010Jens Petter Gitlesen This article provides an empirical evaluation of a hierarchical approach to modeling commuting flows. As the gravity family of spatial interaction models represents a benchmark for empirical evaluation, we begin by reviewing basic aspects of these models. The hierarchical modeling framework is the same that Thorsen, Ubøe, and Nævdal (1999) used. However, because some modifications are required to construct a more workable model, we undertake a relatively detailed presentation of the model, rather than merely referring to the presentation in Thorsen, Ubøe, and Nævdal (1999). The model uses a hierarchical specification of a transportation network and the individual search procedure. Journeys to work are determined by the effects of distance deterrence and of intervening opportunities, and by the location of potential destinations relative to alternatives at subsequent levels in a transportation network. The model calibration uses commuting data from a region in western Norway. The estimated parameter values are reasonable, and the explanatory power is very satisfactory when compared with the results of a competing destinations approach. Este artículo presenta una evaluación empírica de un enfoque jerárquico para el modelado de flujos de desplazamientos del lugar de residencia al lugar de trabajo (commuting flows). Los modelos interacción espacial, y en particular los modelos de gravedad representan un buen punto de referencia para esta tarea. Por esta razón, los autores inician el estudio con una revisión de los aspectos básicos de estos modelos. El marco general del modelo jerárquico seleccionado es el mismo que emplean Thorsen, Ubøe y Nævdal (1999). Sin embargo, debido a que algunas modificaciones son necesarias para construir un método más viable, los autores presentan su versión del modelo de manera detallada en lugar de sólo hacer referencia a la versión de Thorsen, Ubøe y Nævdal. El modelo modificado propuesto emplea una especificación jerárquica para una red de transporte y hace uso de un procedimiento de búsqueda individual (individual search procedure). Los desplazamientos hacia el lugar de trabajo son establecidos en base a 1) los efectos limitantes de distancia de las oportunidades de desplazamiento, y 2) la localización de los posibles destinos medida en relación a las distintas alternativas existentes en los niveles inferiores de la jerarquía de la red de transporte. La calibración del modelo utiliza datos de desplazamientos de una región en el oeste de Noruega. Finalmente, los autores concluyen que los valores de los parámetros estimados obtenidos son razonables, y que el poder explicativo del modelo es muy satisfactorio en comparación a los resultados obtenidos por un análisis comparativo/competitivo de destinos a (competing destinations). [source] The carrying capacity of ecosystemsGLOBAL ECOLOGY, Issue 6 2004Pablo Del Monte-Luna ABSTRACT We analyse the concept of carrying capacity (CC), from populations to the biosphere, and offer a definition suitable for any level. For communities and ecosystems, the CC evokes density-dependence assumptions analogous to those of population dynamics. At the biosphere level, human CC is uncertain and dynamic, leading to apprehensive rather than practical conclusions. The term CC is widely used among ecological disciplines but remains vague and elusive. We propose the following definition: the CC is ,the limit of growth or development of each and all hierarchical levels of biological integration, beginning with the population, and shaped by processes and interdependent relationships between finite resources and the consumers of those resources'. The restrictions of the concept relate to the hierarchical approach. Emergent properties arise at each level, and environmental heterogeneity restrains the measurement and application of the CC. Because the CC entails a myriad of interrelated, ever-changing biotic and abiotic factors, it must not be assumed constant, if we are to derive more effective and realistic management schemes. At the ecosystem level, stability and resilience are dynamic components of the CC. Historical processes that help shape global biodiversity (e.g. continental drift, glaciations) are likely drivers of large-scale changes in the earth's CC. Finally, world population growth and consumption of resources by humanity will necessitate modifications to the paradigm of sustainable development, and demand a clear and fundamental understanding of how CC operates across all biological levels. [source] Hierarchical multivariate analysis of cockle phenomenaJOURNAL OF CHEMOMETRICS, Issue 10 2003Zdravko I. Stefanov Abstract The phenomena called cockle are small wrinkles on the paper surface that appear during paper production. This condition poses significant economic and operability problems in the production of magazine paper, as it deteriorates the printabilty of the paper. There are many and varied sources that can lead to cockle, and their detection is often very complicated. In this work a multivariate hierarchical approach is proposed to analyze the cause of cockle. The hierarchy has two levels, the first of which is a three-way decomposition and analysis of the data collected from sections of a paper machine. The second level is a two-way decomposition and analysis between the combined loadings from the three-way decomposition and the measured cockle data. The results show that this approach is capable of identifying the important process sections and process variables, in spite of the large dimensionality of the problem. Data analyzed from two real industrial paper machines, involving several grades of paper, are used to demonstrate the proposed hierarchical approach. Copyright © 2003 John Wiley & Sons, Ltd. [source] Y haplogroups and aggressive behavior in a Pakistani ethnic groupAGGRESSIVE BEHAVIOR, Issue 1 2009S. Shoaib Shah Abstract Studies show that personality dimensions such as aggression are influenced by genetic factors and that allelic variants located on the Y chromosome influence such behavior. We investigated polymorphisms on the male-specific region of the human Y chromosome in 156 unrelated males from the same ethnic background, who were administered the Punjabi translation of the Buss and Perry Aggression Questionnaire that measures four aspects that constitute aggressive behavior, i.e. physical aggression, verbal aggression, anger, and hostility. A value of .85 for Cronbach's coefficient , indicates considerable internal consistency and suggests that the psychometric properties of the aggression questionnaire can be adapted for the Pakistani population. A mean score±SD of 69.70±19.95 was obtained for the questionnaire. Each individual was genotyped following a phylogenetic hierarchical approach to define evolutionary Y haplogroups. Five Y haplogroups that are commonly found in Eurasia and Pakistan comprised 87% (n=136) of the population sample, with one haplogroup, R1a1, constituting 55% of the sampled population. A comparison of the total and four subscale mean scores across the five common Y haplogroups that were present at a frequency ,3% in this ethnic group revealed no overall significant differences. However, effect-size comparisons allowed us to detect an association of the haplogroups R2 (Cohen's d statistic=.448,.732) and R1a1 (d=.107,.448) with lower self-reported aggression mean scores in this population. Aggr. Behav. 35:68,74, 2009. © 2008 Wiley-Liss, Inc. [source] Facial Soft Tissue Depths in Craniofacial Identification (Part I): An Analytical Review of the Published Adult Data,JOURNAL OF FORENSIC SCIENCES, Issue 6 2008Carl N. Stephan Ph.D. Abstract:, With the ever increasing production of average soft tissue depth studies, data are becoming increasingly complex, less standardized, and more unwieldy. So far, no overarching review has been attempted to determine: the validity of continued data collection; the usefulness of the existing data subcategorizations; or if a synthesis is possible to produce a manageable soft tissue depth library. While a principal components analysis would provide the best foundation for such an assessment, this type of investigation is not currently possible because of a lack of easily accessible raw data (first, many studies are narrow; second, raw data are infrequently published and/or stored and are not always shared by some authors). This paper provides an alternate means of investigation using an hierarchical approach to review and compare the effects of single variables on published mean values for adults whilst acknowledging measurement errors and within-group variation. The results revealed: (i) no clear secular trends at frequently investigated landmarks; (ii) wide variation in soft tissue depth measures between different measurement techniques irrespective of whether living persons or cadavers were considered; (iii) no clear clustering of non-Caucasoid data far from the Caucasoid means; and (iv) minor differences between males and females. Consequently, the data were pooled across studies using weighted means and standard deviations to cancel out random and opposing study-specific errors, and to produce a single soft tissue depth table with increased sample sizes (e.g., 6786 individuals at pogonion). [source] Refining diagnoses: applying the DC-LD to an Irish population with intellectual disabilityJOURNAL OF INTELLECTUAL DISABILITY RESEARCH, Issue 11 2005A. Felstrom Abstract Background The diagnostic criteria for psychiatric disorders for use with adults with learning disabilities/mental retardation (DC-LD) is a diagnostic tool developed in 2001 to improve upon existing classification systems for adults with learning disability. The aim of this study was to apply the classification system described by the DC-LD to a residential intellectual disability (ID) population to examine whether it improved our diagnostic understanding of residents. Methods Chart reviews of 113 of 178 people in a residential ID service were conducted. For each resident, information was recorded according to the DC-LD multi-axial system. Each resident's case was then discussed with a member of nursing staff familiar with the resident. If diagnosis was unclear, the case was discussed with a senior clinical psychiatrist. Results The percentage of residents with a moderate to profound ID was 87.6%. In total, 94 diagnoses of psychiatric illness (Axis III, Level B, DC-LD) were made. Of those 94 diagnoses, seven new diagnoses were found because of DC-LD criteria. Of the total number of psychiatric diagnoses made, 72.3% were non-specific, residual category diagnoses. A total of 79 residents (69.9%) had at least one behaviour problem diagnosed on Axis III, Level D, Problem behaviours. Fifty-six (49.6%) of residents in this sample had co-morbid epilepsy. Conclusions In people with moderate to profound learning disabilities, diagnosis continues to be challenging. The DC-LD is a useful tool in helping to clarify diagnoses in this population by providing revised criteria and a system to classify problem behaviours. The DC-LD would be more helpful if specific axes were included to document medical and psychosocial problems independently from other diagnoses. Further research is warranted to determine whether the DC-LD hierarchical approach to diagnosis improves diagnostic validity. [source] Evidence based practice and its critics: what is a nurse manager to do?JOURNAL OF NURSING MANAGEMENT, Issue 1 2010PETER O'HALLORAN PhD o'halloran p., porter s. & blackwood b. (2010) Journal of Nursing Management18, 90,95 Evidence based practice and its critics: what is a nurse manager to do? Aim(s), The purpose is to discuss the arguments against the evidence based practice (EBP) movement and suggest how nursing management might respond. Background, EBP is a pervasive approach to directing and regulating nursing care. There are, however, fierce critics who argue that it is fundamentally flawed and detrimental to patient care. Evaluation, We consider some of the more radical criticisms of EBP, weighing the arguments and reflecting on the extent to which alleged short-comings are supported in the literature. Postmodernist critics are amongst the most vocal and are therefore our principal focus. Key issue(s), ,Best evidence' implies a hierarchical approach to knowledge which excludes other forms of evidence that are needed to understand the complexity of care. Evidence based guidelines tend to stifle critical thinking amongst nurses. Conclusion(s), While EBP is increasingly open to a range of research methodologies, it still largely subscribes to a hierarchy of evidence, even though this approach to addressing the complexities of healthcare is limiting. Although the EBP approach can be shown to stifle critical thinking, this is not inherent to the approach, which can lend itself to supporting professional nursing practice. Implications for nursing management, Nursing managers should neither abandon EBP nor accept it uncritically. [source] A Bayesian hierarchical approach to ensemble weather forecastingJOURNAL OF THE ROYAL STATISTICAL SOCIETY: SERIES C (APPLIED STATISTICS), Issue 3 2010A. F. Di Narzo Summary., In meteorology, the traditional approach to forecasting employs deterministic models mimicking atmospheric dynamics. Forecast uncertainty due to partial knowledge of the initial conditions is tackled by ensemble predictions systems. Probabilistic forecasting is a relatively new approach which may properly account for all sources of uncertainty. We propose a hierarchical Bayesian model which develops this idea and makes it possible to deal with ensemble predictions systems with non-identifiable members by using a suitable definition of the second level of the model. An application to Italian small-scale temperature data is shown. [source] Prospective studies of exposure to an environmental contaminant: The challenge of hypothesis testing in a multivariate correlational contextPSYCHOLOGY IN THE SCHOOLS, Issue 6 2004Joseph L. Jacobson In this paper, we respond to the criticisms and concerns raised by D.V. Cicchetti, A.S. Kaufman, & S.S. Sparrow (this issue) in their review of the PCB literature, with particular attention to our own research in Michigan. We agree that multiple comparisons and functional significance are issues that would benefit from more discussion. However, because the effects associated with exposure to environmental contaminants are generally subtle, the risk of Type II error would be unacceptably high if researchers were to adopt the authors' recommendation to use a Bonferroni correction. We describe the hierarchical approach we have used to deal with the issue of multiple comparisons, which emphasizes the need to base interpretation on consistent patterns in the data and on replicated findings. The issue of confounding is one that has received considerable attention in the PCB studies and, given that one can never measure every possible confounder, the range of control variables that have been evaluated is impressive. We disagree with the authors' assertion that only standardized test scores are sufficiently reliable for use in these studies; behavioral teratogens often involve subtle effects, which can be identified most effectively by innovative, narrow-band tests that have not yet been normed. Moreover, longitudinal statistical analysis is not necessarily the method of choice for the issues being addressed in this literature. One important new development that Cicchetti et al. fail to note is the emergence of evidence from both the Michigan and Dutch cohorts indicating that breast-fed children are markedly less vulnerable. It is not yet clear to what degree this protective effect is attributable to nutrients in breast milk or to more optimal intellectual stimulation by nursing mothers, or both. However, the discovery of effect modifiers that can explain individual differences in vulnerability marks an important advance in our growing understanding of the teratogenic effects of exposure to environmental contaminants on child development. © 2004 Wiley Periodicals, Inc. Psychol Schs 41: 625,637, 2004. [source] What Small Spatial Scales Are Relevant as Electoral Contexts for Individual Voters?AMERICAN JOURNAL OF POLITICAL SCIENCE, Issue 3 2009The Importance of the Household on Turnout at the 2001 General Election For many years, scholars of voting behavior have been thwarted in their attempts to identify micro spatial variations in turnout by data limitations. This has meant that most analyses have been ecological, which has implications for valid inference. Here, for the first time, a hierarchical approach is used to show the relative importance of several micro spatial scales, including the household, on voter participation. The findings highlight the importance of the household context. While those who live together often turn out together, the relative level of clustering within households as opposed to between geographical areas is found to be more important for two-person households compared to other households. Even after taking account of whether individuals are likely to self-select others from similar social backgrounds or with similar political attitudes, there is strong evidence of large and significant household effects on voter participation. [source] LARGE-SCALE SIMULATION OF THE HUMAN ARTERIAL TREECLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 2 2009L Grinberg SUMMARY 1Full-scale simulations of the virtual physiological human (VPH) will require significant advances in modelling, multiscale mathematics, scientific computing and further advances in medical imaging. Herein, we review some of the main issues that need to be resolved in order to make three-dimensional (3D) simulations of blood flow in the human arterial tree feasible in the near future. 2A straightforward approach is computationally prohibitive even on the emerging petaflop supercomputers, so a three-level hierarchical approach based on vessel size is required, consisting of: (i) a macrovascular network (MaN); (ii) a mesovascular network (MeN); and (iii) a microvascular network (MiN). We present recent simulations of MaN obtained by solving the 3D Navier,Stokes equations on arterial networks with tens of arteries and bifurcations and accounting for the neglected dynamics through proper boundary conditions. 3A multiscale simulation coupling MaN,MeN,MiN and running on hundreds of thousands of processors on petaflop computers will require no more than a few CPU hours per cardiac cycle within the next 5 years. The rapidly growing capacity of supercomputing centres opens up the possibility of simulation studies of cardiovascular diseases, drug delivery, perfusion in the brain and other pathologies. [source] Hierarchical Models in Environmental ScienceINTERNATIONAL STATISTICAL REVIEW, Issue 2 2003Christopher K. Wikle Summary Environmental systems are complicated. They include very intricate spatio-temporal processes, interacting on a wide variety of scales. There is increasingly vast amounts of data for such processes from geographical information systems, remote sensing platforms, monitoring networks, and computer models. In addition, often there is a great variety of scientific knowledge available for such systems, from partial differential equations based on first principles to panel surveys. It is argued that it is not generally adequate to consider such processes from a joint perspective. Instead, the processes often must be considered as a coherently linked system of conditional models. This paper provides a brief overview of hierarchical approaches applied to environmental processes. The key elements of such models can be considered in three general stages, the data stage, process stage, and parameter stage. In each stage, complicated dependence structure is mitigated by conditioning. For example, the data stage can incorporate measurement errors as well as multiple datasets with varying supports. The process and parameter stages can allow spatial and spatio-temporal processes as well as the direct inclusion of scientific knowledge. The paper concludes with a discussion of some outstanding problems in hierarchical modelling of environmental systems, including the need for new collaboration approaches. Résumé Les systèmes environnementaux sont complexes. Ils incluent des processus spatio-temporels trés complexes, interagissant sur une large variété d'échelles. II existe des quantités de plus en plus grandes de données sur de tels processus, provenant des systèmes d'information géographiques, des plateformes de télédétection, des réseaux de surveillance et des modèles informatiques. De plus, il y a souvent une grande variété de connaissance scientifique disponible sur de tels systémes, depuis les équations différentielles partielles jusqu'aux enquétes de panels. II est reconnu qu'il n'est généralement pas correct de considerer de tels processus d'une perspective commune. Au contraire, les processus doivent souvent étre examinés comme des systèmes de modèles conditionnels liés de manière cohérente. Cet article fournit un bref aperçu des approches hiérachiques appliquées aux processus environnementaux. Les éléments clés de tels modèles peuvent étre examinés à trois étapes principales: l'étape des donnèes, celle du traitement et celle des paramètres. A chaque étape, la structure complexe de dépendance est atténuée par le conditionnement. Par exemple, le stade des données peut incorporer des erreurs de mesure ainsi que de multiples ensembles de données sous divers supports. Les stades du traitement et des paramétres peuvent admettre des processus spatiaux et spatio-temporels ainsi que l'inclusion directe du savoir scientifique. L'article conclut par une discussion de quelques problèmes en suspens dans la modélisation hiérarchique des systèmes environnementaux, incluant le besoin de nouvelles approches de collaboration. [source] | ||||||||||||||||||||||