bluuebunny/crossref_metadata_2025 huggingface dataset:
Determining causation in epidemiology
Authors: Scheutz Flemming , Poulsen Sven
Published: March 2007

Abstract– Epidemiology uses many methods to identify the causes of disease, although it remains impossible to provide proof that any specific factor is a cause. We are only able to present supporting evidence. We subscribe to the pragmatic view that a factor is indeed a cause if its elimination improves health. We describe a deterministic causal model, where disease develops when the necessary component causes exist in one of several possible constellations of causes, each of which constitutes a sufficient set of component causes. If we accept this concept of disease causation, the notion of multifactorial disease becomes meaningless. We should rather turn our attention to component causes that we can eliminate in order to improve public health. The complex nature of diseases and the fact that it is only possible to present supporting evidence for a causal relationship are some of our reasons for basing the identification of causes on a theoretic model or framework. The purpose is to construct and present a model that is complex enough to formalize basic intuitions concerning cause and effect. Finally, conceptual frameworks provide guidance for the use of multivariable statistical techniques and may assist in the interpretation of the results.
Behavioural and emotional problems in children referred to a centre for special dental care
Authors: ten Berge Maaike , Veerkamp Jaap S. J. , Hoogstraten Johan , Prins Pier J. M.
Published: March 2007

Abstract– This study was conducted among 203 children (103 boys) referred to a centre for special dental care because of a high level of dental fear. It was under‐taken to explore to what extent behavioural and emotional problems co‐exist in these children compared with children of a Dutch norm group. The children's parents filled out the parental version of the Child Behaviour Checklist (CBCL), before their first appointment at the centre. The behavioural and emotional problems of the children were assessed by this CBCL, and the mean scores of the children in the study were compared with the mean scores of the norm group. The mean scores on all scales, except on the subscale ‘sex problems’, of the children with a high level of dental fear proved to be significantly higher than the mean scores of the norm group (P≦0.001). The results indicated that children referred to a special dental care centre not only suffer from high dental fear but also have problems in several other behavioural and emotional areas. These problems appear to be heterogeneous; they were found in several specic problem areas, both external and internal.
Extraction of teeth over 5 years in regularly attending adults
Authors: Worthington Helen , Clarkson Jan , Davies Robin
Published: March 2007

Abstract– Objectives: This prospective study was conducted to describe the incidence of tooth extraction in a group of regularly attending adults and to assess factors that are predictive of tooth loss. Methods: Baseline and annual incremental clinical data were obtained from 23 general dental practitioners on a group of their regularly attending, dentate adult patients over a 5‐year period. The patients completed a postal questionnaire with questions relating to dental health behaviours, attitudes and knowledge, and social factors. Results: Complete clinical data were obtained from 2799 patients. Four hundred and seventy (17%) patients underwent extractions, 72% of which were posterior teeth. The majority of extractions were for reasons other than caries (79%). Bivariate analyses revealed many significant differences between patients who underwent extractions and those who did not, with respect to the clinical, social, behavioural and attitudinal variables. The logistic regression model for tooth loss included three clinical variables, number of teeth, crowns and sites with recession. Other variables in the final model included the dentist's and patient's prediction of treatment need, having sensitive teeth, having a sweet tooth, living alone and smoking. The sensitivity for the model was 0.57 with specificity 0.72. Conclusions: This study is unique in its examination of patients and has highlighted that both clinical and other factors are important in predicting who will undergo extractions. Future investigations should assess the consequence of having extractions in terms of health benefit or detriment.
A 2‐year clinical study of two glass ionomer cements used in the atraumatic restorative treatment (ART) technique
Authors: Tak Ho Tom Fu , Smales Roger Joseph , Sang Fang Daniel Tak
Published: March 2007

Abstract– The purpose of the study was to evaluate, in a clinical study over 2 years, the deterioration of two glass ionomer cements used with the atraumatic restorative treatment (ART) technique or approach. Fifty‐five Fuji IX and 45 ChemFil Superior restorations were placed randomly in 23 adult patients, mainly in small occlusal preparations in molar teeth. The restorations were placed in a dental hospital by one dentist using the ART technique. Photographs, radiographs and replicas were obtained at baseline and subsequent recalls. Both cements were easy to mix and place, but the radiolucency of ChemFil Superior was a disadvantage. Both cements also showed early high losses of sealant and restorative material. After 2 years, 34.5% of the sealants appeared to be completely lost, with caries recorded in 5.3% of the exposed fissures. In some instances, these small lesions may have been present, but not detected clinically, at the time of sealing. Restoration failures of 7.0% were from wear and fracture of the cements and recurrent caries. Mean cumulative wear was 83.1 μ m for Fuji IX and 104.0 μm for ChemFil Superior, which was not statistically significant. The cements became darker after their placement to more closely match the restored teeth, but there were few exact matches. There was no surface staining and only minor marginal discrepancies and staining associated with the restorations. Although the short‐term clinical performance of the two glass ionomer cements was reasonable, the materials require further improvements in their mechanical properties, to reduce sealant losses and wear. The cements evaluated appear suitable for restricted use only, in posterior teeth.
Association of edentulousness with systemic factors in elderly people living at home
Authors: Xie Qiufei , Ainamo Anja
Published: March 2007

Abstract– Objective: To examine the association of edentulousness with systemic factors: age, gender, tobacco‐smoking, alcohol intake, body mass index, functioning in daily living, cortical thickness at the mandibular angle, and systemic diseases: bone‐fracture (an indicator for osteoporosis), diabetes, thyroid disease, hyperparathyroidism, asthma, heart failure, hypertension. Methods: The study population comprised 293 elderly subjects, 124 (42%) edentulous and 169 (58%) dentate. The data from clinical and radiographic examinations and structured interviews were analyzed by multiple logistic regression. Results: When edentulousness in both the mandible and the maxilla was considered, history of bone fracture and tobacco‐smoking were significantly related to complete edentulousness with odds ratios (OR) of 2.51 (95% CI: 1.47–4.28) and 2.42 (95% CI: 1.32–4.43) respectively, associations independent of age and gender. A similar association was found for the edentulous mandible. In the elderly subjects with an edentulous maxilla, besides the significant factors of history of bone fracture and tobacco‐smoking, asthma was also associated with edentulousness at an odds ratio of 10.81 (95% CI: 1.38–84.66), oldest subjects most often being edentulous (OR: 2.23, 95% CI: 1.13–4.39). Diabetes was not related to edentulousness either in the mandible or in the maxilla. Conclusions: The finding of associations of history of bone fracture, tobacco‐smoking, and asthma with edentulousness emphasizes the association of systemic conditions with edentulousness. Advanced age was related to an edentulous maxilla. The relationship between asthma and total tooth loss in the maxilla might suggest a local oral effect of medications used by asthmatic patients.
Effect of fluoridated salt intake in infancy: a blind caries and fluorosis study in 8th grade Hungarian pupils
Authors: Stephen Kenneth W. , Macpherson Lorna M. D. , Gorzo Istvan , Gilmour W. Harper
Published: March 2007

Abstract– Salt fluoridation is effective at inhibiting caries, but fluorosis prevalence data are deficient. Objectives: The purpose was to undertake a blind study of caries and tooth mottling in 8th grade school pupils from south‐east Hungary who had resided (test) or not resided (control), until November 1985, in a 350 ppm F−/kg domestic salt‐fluoridated area during their early years of life. Methods: In Szeged, blind clinical caries and anterior tooth mottling scoring (+10% repeats) of 49 previously salt‐fluoridated (mean age 14.14 years) and 59 non‐salt‐fluoridated subjects (mean age 14.08 years) were undertaken by one examiner, in June 1997. In addition, radiographic and photographic recordings were taken. In Glasgow, four dental and two lay staff scored the projected 35 mm colour transparencies (+10% repeats) of each pupil's six upper anterior teeth, for tooth mottling. All clinical, radiographic and photographic data were then analysed. Results: Mean DMFS scores were 9.18 (SD = 10.72) for test users and 4.51 (SD = 6.24) for control users (P < 0.01) and, based on repeat observations, clinical reliability = 0.99; X‐ray reliability = 0.95. Clinically, three test children had fluorosis of 10 teeth, with eight teeth in two controls. Photographic scoring by the clinical examiner gave a 97.2% clinical match, while photographic agreements for all four dentist pairs were 92.5%–97.2%, with lay observers' agreements at 89.8%. For both groups, 10% repeats produced 98.5% agreements. In a sole test case “fluorosis” photographic unanimity was obtained, and non‐unanimous “possible fluorosis” was recorded by two to four panel members for only three other test and two control subjects. Conclusions: No evidence was found that significant anterior tooth fluorosis resulted in subjects exposed previously to 350 ppm F−/kg domestic salt from birth to 2.3–4.8 years of age. However, no caries benefit was demonstrated after the 11.5‐year salt fluoridation gap. Caries differences seemed social class‐related, city‐based controls having less disease than rural test subjects, in spite of an identical F− tablet regimen in all schools from 1987, until subjects were 10 years old. These data emphasise (a) the superiority of sustained community‐delivered fluoridation and (b) the need to maintain constant fluoride delivery to tooth surfaces, certainly well beyond 10 years of age.
Attachment loss in rural Chinese children over a 3‐year period
Authors: Suda Reiko , Cao Cai‐Fang , Suzuki Motoyuki , Hasegawa Kohji , Sasa Ryuji
Published: March 2007

Abstract– Objectives: The periodontal condition of 84 children (9–14 years old, 38 males and 46 females) in a rural area of China was monitored over a 3‐year period in order to determine the clinical parameters that act as risk factors for attachment loss. Methods: Plaque and calculus accumulation (PSS and CI), modified gingival index (MGI), pocket depth (PD) and attachment level (AL) of two quadrants of each child were examined in 1993 and 1996. Following calculation of the mean of each of these parameters and statistical analysis of the change in each of the clinical parameters over the 3‐year period, the relationship between attachment loss and clinical parameters was analyzed using multiple regression analysis. Results: At the beginning of this study, the mean values for males and females were 3.66 and 3.58 for PSS, 1.22 and 1.17 for MGI, 1.07 and 0.90 for CI, 2.21 and 2.22 for PD, and both 0.02 for AL respectively. No significant t difference between males and females was observed. After 3 years, all except mean PSS had increased significantly. Multiple regression analysis indicated that AL correlated only to age (P < 0.01). In 1993, although the AL was ≧1 mm for at least one site in 21 children, none had an AL≧3 mm. In 1996, the number of children with an AL≧1 mm had increased to 63, and nine of these children exhibited 3 mm AL (one to six sites per child). No other significant differences were observed between the clinical data of these nine children and those of the other children. Conclusion: Although attachment loss tended to increase with age, no clinical parameters correlated with attachment loss in children.
The provision and outcome of orthodontic services in a Norwegian community: a longitudinal cohort study
Authors: Fernandes Lucete M. , Espeland Lisen , Stenvik Arild
Published: March 2007

Abstract– In a systematic child dental care system, professionals, consumers, and purchasers have a common interest in ensuring that provision and outcome of orthodontic care fulfill the goals of the service and the public's expectations. The purpose of this prospective study was to examine whether treatment was in fact provided to children with a normative treatment need, and also to assess the outcome of treatment. The baseline data were established for a sample of 83 11‐year‐olds before decisions about orthodontic treatment had been made, by recording the individuals' orthodontic concern as reported in questionnaires and their occlusal condition according to an index of orthodontic treatment need (NOTI). At re‐examination at the age of 16 years, it was also recorded whether the individual had received orthodontic treatment. Most individuals (83%) with a normative need had been treated as well as some individuals without need but who had expressed orthodontic concern. Treatment had resulted in occlusal improvement (‘health gain’) in most patients, and generally this improvement paralleled a decrease in concern. The goals of the orthodontic service seem to have been fulfilled to the extent that residual treatment need was infrequent. The high treatment rate (63%) and standard may explain why all individuals, both treated and untreated, expressed satisfaction with their dental appearance at 16 years of age.
Gliadain, a gibberellin‐inducible cysteine proteinase occurring in germinating seeds of wheat,Triticum aestivumL., specifically digests gliadin and is regulated by intrinsic cystatins
Authors: Kiyosaki Toshihiro , Matsumoto Ichiro , Asakura Tomiko , Funaki Junko , Kuroda Masaharu , Misaka Takumi , Arai Soichi , Abe Keiko
Published: March 2007

We cloned a new cysteine proteinase of wheat seed origin, which hydrolyzed the storage protein gliadin almost specifically, and was named gliadain. Gliadain mRNA was expressed 1 day after the start of seed imbibition, and showed a gradual increase thereafter. Gliadain expression was suppressed when uniconazol, a gibberellin synthesis inhibitor, was added to germinating seeds. Histochemical detection with anti‐gliadain serum indicated that gliadain was present in the aleurone layer and also that its expression intensity increased in sites nearer the embryo. The enzymological characteristics of gliadain were investigated using recombinant glutathioneS‐transferase (GST)–progliadain fusion protein produced inEscherichia coli. The GST–progliadain almost specifically digested gliadin into low molecular mass peptides. These results indicate that gliadain is produced via gibberellin‐mediated gene activation in aleurone cells and secreted into the endosperm to digest its storage proteins. Enzymologically, the GST–progliadain hydrolyzed benzyloxycarbonyl‐Phe‐Arg‐7‐amino‐4‐methylcoumarin (Z‐Phe‐Arg‐NH2‐Mec) atKm = 9.5 µm, which is equivalent to theKmvalue for hydrolysis of this substrate by cathepsin L. Hydrolysis was inhibited by two wheat cystatins, WC1 and WC4, with IC50values of 1.7 × 10−8and 5.0 × 10−8 m, respectively. These values are comparable with those found for GST–progliadain inhibition by E‐64 and egg‐white cystatin, and are consistent with the possibility that, in germinating wheat seeds, gliadain is under the control of intrinsic cystatins.
Mechanistic aspects and redox properties of hyperthermophilic L‐proline dehydrogenase from Pyrococcus furiosus related to dimethylglycine dehydrogenase/oxidase
Authors: Monaghan Phillip J. , Leys David , Scrutton Nigel S.
Published: March 2007

Two ORFs encoding a protein related to bacterial dimethylglycine oxidase were cloned from Pyrococcus furiosus DSM 3638. The protein was expressed in Escherichia coli, purified, and shown to be a flavoprotein amine dehydrogenase. The enzyme oxidizes the secondary amines l‐proline, l‐pipecolic acid and sarcosine, with optimal catalytic activity towards l‐proline. The holoenzyme contains one FAD, FMN and ATP per αβ complex, is not reduced by sulfite, and reoxidizes slowly following reduction, which is typical of flavoprotein dehydrogenases. Isolation of the enzyme in a form containing only FAD cofactor allowed detailed pH dependence studies of the reaction with l‐proline, for which a bell‐shaped dependence (pKa values 7.0 ± 0.2 and 7.6 ± 0.2) for kcat/Km as a function of pH was observed. The pH dependence of kcat is sigmoidal, described by a single macroscopic pKa of 7.7 ± 0.1, tentatively attributed to ionization of l‐proline in the Michaelis complex. The preliminary crystal structure of the enzyme revealed active site residues conserved in related amine dehydrogenases and potentially implicated in catalysis. Studies with H225A, H225Q and Y251F mutants ruled out participation of these residues in a carbanion‐type mechanism. The midpoint potential of enzyme‐bound FAD has a linear temperature dependence (− 3.1 ± 0.05 mV·C°−1), and extrapolation to physiologic growth temperature for P. furiosus (100 °C) yields a value of − 407 ± 5 mV for the two‐electron reduction of enzyme‐bound FAD. These studies provide the first detailed account of the kinetic/redox properties of this hyperthermophilic l‐proline dehydrogenase. Implications for its mechanism of action are discussed.
Post‐translational cleavage of recombinantly expressed nitrilase from Rhodococcus rhodochrous J1 yields a stable, active helical form
Authors: Thuku R. Ndoria , Weber Brandon W. , Varsani Arvind , Sewell B. Trevor
Published: March 2007

Nitrilases convert nitriles to the corresponding carboxylic acids and ammonia. The nitrilase from Rhodococcus rhodochrous J1 is known to be inactive as a dimer but to become active on oligomerization. The recombinant enzyme undergoes post‐translational cleavage at approximately residue 327, resulting in the formation of active, helical homo‐oligomers. Determining the 3D structure of these helices using electron microscopy, followed by fitting the stain envelope with a model based on homology with other members of the nitrilase superfamily, enables the interacting surfaces to be identified. This also suggests that the reason for formation of the helices is related to the removal of steric hindrance arising from the 39 C‐terminal amino acids from the wild‐type protein. The helical form can be generated by expressing only residues 1–327.
Structural basis for cyclodextrin recognition by Thermoactinomyces vulgaris cyclo/maltodextrin‐binding protein
Authors: Tonozuka Takashi , Sogawa Akiko , Yamada Mitsugu , Matsumoto Naoki , Yoshida Hiromi , Kamitori Shigehiro , Ichikawa Kazuhiro , Mizuno Masahiro , Nishikawa Atsushi , Sakano Yoshiyuki
Published: March 2007

The crystal structure of a Thermoactinomyces vulgaris cyclo/maltodextrin‐binding protein (TvuCMBP) complexed with γ‐cyclodextrin has been determined. Like Escherichia coli maltodextrin‐binding protein (EcoMBP) and other bacterial sugar‐binding proteins, TvuCMBP consists of two domains, an N‐ and a C‐domain, both of which are composed of a central β‐sheet surrounded by α‐helices; the domains are joined by a hinge region containing three segments. γ‐Cyclodextrin is located at a cleft formed by the two domains. A common functional conformational change has been reported in this protein family, which involves switching from an open form to a sugar‐transporter bindable form, designated a closed form. The TvuCMBP–γ‐cyclodextrin complex structurally resembles the closed form of EcoMBP, indicating that TvuCMBP complexed with γ‐cyclodextrin adopts the closed form. The fluorescence measurements also showed that the affinities of TvuCMBP for cyclodextrins were almost equal to those for maltooligosaccharides. Despite having similar folds, the sugar‐binding site of the N‐domain part of TvuCMBP and other bacterial sugar‐binding proteins are strikingly different. In TvuCMBP, the side‐chain of Leu59 protrudes from the N‐domain part into the sugar‐binding cleft and orients toward the central cavity of γ‐cyclodextrin, thus Leu59 appears to play the key role in binding. The cleft of the sugar‐binding site of TvuCMBP is also wider than that of EcoMBP. These findings suggest that the sugar‐binding site of the N‐domain part and the wide cleft are critical in determining the specificity of TvuCMBP for γ‐cyclodextrin.
Attenuation of cardiac mitochondrial dysfunction by melatonin in septic mice
Authors: Escames Germaine , López Luis C. , Ortiz Francisco , López Ana , García José A. , Ros Eduardo , Acuña‐Castroviejo Darío
Published: March 2007

The existence of an inducible mitochondrial nitric oxide synthase has been recently related to the nitrosative/oxidative damage and mitochondrial dysfunction that occurs during endotoxemia. Melatonin inhibits both inducible nitric oxide synthase and inducible mitochondrial nitric oxide synthase activities, a finding related to the antiseptic properties of the indoleamine. Hence, we examined the changes in inducible nitric oxide synthase/inducible mitochondrial nitric oxide synthase expression and activity, bioenergetics and oxidative stress in heart mitochondria following cecal ligation and puncture‐induced sepsis in wild‐type (iNOS+/+) and inducible nitric oxide synthase‐deficient (iNOS–/–) mice. We also evaluated whether melatonin reduces the expression of inducible nitric oxide synthase/inducible mitochondrial nitric oxide synthase, and whether this inhibition improves mitochondrial function in this experimental paradigm. The results show that cecal ligation and puncture induced an increase of inducible mitochondrial nitric oxide synthase in iNOS+/+ mice that was accompanied by oxidative stress, respiratory chain impairment, and reduced ATP production, although the ATPase activity remained unchanged. Real‐time PCR analysis showed that induction of inducible nitric oxide synthase during sepsis was related to the increase of inducible mitochondrial nitric oxide synthase activity, as both inducible nitric oxide synthase and inducible mitochondrial nitric oxide synthase were absent in iNOS–/– mice. The induction of inducible mitochondrial nitric oxide synthase was associated with mitochondrial dysfunction, because heart mitochondria from iNOS–/– mice were unaffected during sepsis. Melatonin treatment blunted sepsis‐induced inducible nitric oxide synthase/inducible mitochondrial nitric oxide synthase isoforms, prevented the impairment of mitochondrial homeostasis under sepsis, and restored ATP production. These properties of melatonin should be considered in clinical sepsis.
Latin Hypercube Approach to Estimate Uncertainty in Ground Water Vulnerability
Authors: Gurdak Jason J. , McCray John E. , Thyne Geoffrey , Qi Sharon L.
Published: March 2007

A methodology is proposed to quantify prediction uncertainty associated with ground water vulnerability models that were developed through an approach that coupled multivariate logistic regression with a geographic information system (GIS). This method uses Latin hypercube sampling (LHS) to illustrate the propagation of input error and estimate uncertainty associated with the logistic regression predictions of ground water vulnerability. Central to the proposed method is the assumption that prediction uncertainty in ground water vulnerability models is a function of input error propagation from uncertainty in the estimated logistic regression model coefficients (model error) and the values of explanatory variables represented in the GIS (data error). Input probability distributions that represent both model and data error sources of uncertainty were simultaneously sampled using a Latin hypercube approach with logistic regression calculations of probability of elevated nonpoint source contaminants in ground water. The resulting probability distribution represents the prediction intervals and associated uncertainty of the ground water vulnerability predictions. The method is illustrated through a ground water vulnerability assessment of the High Plains regional aquifer. Results of the LHS simulations reveal significant prediction uncertainties that vary spatially across the regional aquifer. Additionally, the proposed method enables a spatial deconstruction of the prediction uncertainty that can lead to improved prediction of ground water vulnerability.
Nonconceptual Content
Authors: Toribio Josefa
Published: March 2007

Nonconceptualists maintain that there are ways of representing the world that do not reflect the concepts a creature possesses. They claim that the content of these representational states is genuine content because it is subject to correctness conditions, but it is nonconceptual because the creature to which we attribute it need not possess any of the concepts involved in the specification of that content. Appeals to nonconceptual content have seemed especially useful in attempts to capture the representational properties of perceptual experiences, the representational states of pre‐linguistic children and non‐human animals, the states of subpersonal visual information‐processing systems, and the subdoxastic states involved in tacit knowledge of the grammar of a language. Nonconceptual content is also invoked in the explanation of concept possession, concept acquisition, sensorimotor behaviour, and in the analysis of the notion of self‐consciousness. The notion of nonconceptual content plays an important role in many discussions about the relationships between perception and thought.
Functional Neuroimaging Studies of Syntactic Processing in Sentence Comprehension: A Critical Selective Review
Authors: Caplan David
Published: March 2007

This article critically reviews recent papers that use functional neuroimaging to localize syntactic representations, Universal Grammar, parsing operations, and the working memory system that supports parsing. It is concluded that greater control over experimental conditions is needed for studies to provide convincing evidence about the neural basis for these cognitive functions.
Three Conundrums of Language Lateralization
Authors: Baynes Kathleen , Long Debra L.
Published: March 2007

The lateralization of language to the left hemisphere of the brain in most right‐handed individuals is well established; however, this arrangement has no widely accepted theoretical explanation. The distribution of language across the cerebral hemispheres raises issues and contradictions that are difficult for any theory to accommodate. In this article, we review three puzzles about the lateralization of language: (1) the clinical literature reveals profound deficits in language only after left‐hemisphere damage, but the brain imaging literature shows bilateral activation in most language tasks; (2) language is left‐hemisphere dominant in most individuals yet deviation from this pattern does not result in language dysfunction; and (3) lateralization and handedness are related, but the factors that underlie this relation are unknown. We also briefly discuss evolutionary and genetic theories that have been advanced to explain lateralization.
The Form of Referential Expressions in Discourse
Authors: Almor Amit , Nair Veena A.
Published: March 2007

Most instances of real‐life language use involve discourses in which several sentences or utterances are coherently linked through the use of repeated references. Repeated reference can take many forms, and the choice of referential form has been the focus of much research in several related fields. In this article we distinguish between three main approaches: one that addresses the ‘why’ question – why are certain forms used in certain contexts; one that addresses the ‘how’ question – how are different forms processed; and one that aims to answer both questions by seriously considering both the discourse function of referential expressions, and the cognitive mechanisms that underlie their processing cost. We argue that only the latter approach is capable of providing a complete view of referential processing, and that in so doing it may also answer a more profound ‘why’ question – why does language offer multiple referential forms.
Beyond the Dichotomies in Technology for Development
Authors: Wilson Gordon
Published: March 2007

That technology is essential for development has been written many times. However, a few years ago, technology was increasingly seen as part of a problem that contributed to the depoliticisation of development and reinforced existing societal structures. In response, this century has seen a reconceptualisation of technology's role, alongside that of science. Thus, it is now seen as part of a system of plural knowledges in contrast to its previous role as major player. The challenges of this reconceptualised role are (1) to promote synergies between different knowledges through dialogue and respect for difference, (2) to generate new knowledge through ‘learning with’, in addition to recycling existing knowledge through ‘learning from’, each other, and (3) to manage power relations so that no knowledge is intrinsically favoured (or put last). These challenges represent a call to lay to rest old dichotomies and antagonisms between different kinds of knowledge and to avoid inventing new ones.
Geographies of Voluntarism: Mapping the Terrain
Authors: Milligan Christine
Published: March 2007

In the last decade or so a body of geographical work has begun to emerge that examines, in various ways, the interrelationship between people, place, volunteering and the voluntary sector. Work in this field is spread across a number of geographical subdisciplines, from social, health and development to political geography. As a body of work it is increasingly being referred to as ‘geographies of voluntarism’. Focusing specifically on voluntary activity around health and welfare, this article reviews how geographers have begun to critically engage with issues of voluntary activity and space. It draws out how geographical perspectives on voluntarism are contributing to a wider understanding of how and why disparities in voluntary activity occur and the implications for people and places at a range of spatial scales from the global to the local.
Developing Nutrient Criteria for Streams: An Evaluation of the Frequency Distribution Method1
Authors: Suplee Michael W. , Varghese Arun , Cleland Joshua
Published: March 2007

Abstract:  The U.S. Environmental Protection Agency recommends two statistical methods to States and Tribes for developing nutrient criteria. One establishes a criterion as the 75th percentile of a reference‐population frequency distribution, the other uses the 25th percentile of a general‐population distribution; the U.S. Environmental Protection Agency suggests either method results in similar criteria. To evaluate each method, the Montana Department of Environmental Quality (MT DEQ) assembled data from STORET and other sources to create a nutrient general population. MT DEQ’s reference‐stream project provided reference population data. Data were partitioned by ecoregions, and by seasons (winter, runoff, and growing) defined for the project. For each ecoregion and season, nutrient concentrations at the 75th percentile of the reference population were matched to their corresponding concentrations in the general population. Additionally, nutrient concentrations from five regional scientific studies were matched to their corresponding reference population concentrations; each study linked nutrients to impacts on water uses. Reference‐to‐general population matches were highly variable between ecoregions, as nutrients at the 75th percentile of reference corresponded to percentiles ranging from the 4th to the 97th of the general population. In contrast, case studies‐to‐reference matches were more consistent, matching on average to the 86th percentile of reference, with a coefficient of variation of 13%.
Generalized Nondimensional Depth‐Discharge Rating Curves Tested on Florida Streamflow1
Authors: Mueses Auristela , Said Ahmed , Ross Mark
Published: March 2007

Abstract:  A discharge rating is a relationship between stage and discharge at a specific point in a river stream or lake outlet structure. Rating curves are useful for interpolating and perhaps extrapolating flow measurements and for use directly in storage routing models. However, rating data and stations are limited. A generalized nondimensional mathematical expression that describes the rating relation of depth and discharge has been developed and tested against observations from 46 stations in West‐Central Florida. Three approaches were tested in sequence to select the best fit. The proposed model is a log‐linear equation with zero intercept and a slope that fits more than 50% of the stations were analyzed. The model is normalized by the depth and discharge values at 10% exceedance from data published by the U.S. Geological Survey. For ungauged applications, Q10 and d10 were derived from a relationship shown to be reasonably well correlated to the watershed drainage area. The average relative error for this parameter set shows that for the flow range up to the Q10 discharge, better than 30% agreement with the USGS rating data can be expected for about 50% of the stations. Further analysis is required to determine why so many stations exhibit such similar behavior and to identify the criteria or parameters governing the differences.
Alluvial Sedimentation and Erosion in an Urbanizing Watershed, Gwynns Falls, Maryland1
Authors: Colosimo Mark F. , Wilcock Peter R.
Published: March 2007

Abstract:  Earlier measurements of stream channel geometry on 19 reaches were repeated to provide a longitudinal study of stream channel adjustment over 13 years (1987‐2000) in the urbanizing Gwynns Falls, Maryland watershed. We observed both enlargement and reduction in channel size, depending on the extent of upstream development, the timing and location of urbanization and upstream channel adjustment, and the presence of hydrologic constrictions and grade controls. Based on a relatively simple visual assessment of the composition, size, and extent of instream sediment storage, we categorized stream reaches into three phases: aggraded (7 sites), early erosion (7 sites), and late erosion (5 sites). Aggraded sites had point and lateral bars mantled with fine‐grained sediment and experienced some reduction in cross‐sectional area, primarily through the deposition of fine‐grained material on bars in the channel margins. Early erosion sites had smaller bars and increases in channel cross‐sectional area as a consequence of the evacuation of in‐channel fine‐grained sediment. Fine‐grained sediments were either entirely absent or found only at a few high bar elevations at late erosion sites. Sediment evacuation from late erosion sites has both enlarged and simplified channels, as demonstrated by an increase in cross‐sectional area and a strong decrease in channel width variation. Channel cross‐sectional area enlargement, reduced channel width variation, and channel incision were ubiquitous at erosion sites. As a result, overbank flows were less common in the erosion sites as determined by high water marks left by a 2‐year flood that occurred during the study period. Principal causes for channel changes appear to be increased high flow durations and reduced sediment supply. Spatial variation in channel conditions could not be tied simply to sub‐basin impervious cover or watershed area. In‐channel sediment storage is a useful indicator of channel form and adjustment. When combined with information on development and sedimentation conditions in the contributing drainage, instream sediment storage can be used to effectively assess future channel adjustments.
Minimum Wet‐Season Flows and Levels in Southwest Florida Rivers1
Authors: Munson Adam B. , Delfino Joseph J.
Published: March 2007

Abstract:  Regulation of river flows can result in decreased stage fluctuations and alteration of inundation patterns of floodplain wetlands. However, floodplain inundation has historically not been addressed in most minimum flow determinations. Florida law requires the water management districts of the state to establish minimum flows and levels to protect water bodies from significant harm associated with water withdrawals. The Southwest Florida Water Management District utilizes a 15% reduction in habitat criterion as a threshold for defining significant harm to freshwater segments of rivers. Utilizing a multi‐parameter approach and different habitat measures for seasonal flow periods, the District has recommended minimum flow compliance standards for the Alafia, Myakka and middle Peace rivers. For the high‐flow period, the District utilized a 15% reduction in the number of days of floodplain inundation (a temporal loss) as a significant harm threshold. This approach yielded allowable flow reductions of 8% for the Alafia and Peace rivers during the high‐flow season and a 7% allowable reduction of natural flows on the Myakka River. Comparison of changes in flows associated with temporal and spatial loss thresholds indicated that flow reductions required to effect a 15% spatial loss of habitat on the Alafia, Myakka and middle Peace rivers are higher than those that would yield a 15% temporal loss. This indicates that with respect to natural flow protection, the District’s consideration of temporal reductions in habitat for establishing minimum river flows for seasonal high‐flow periods is more conservative than the use of a spatial loss criterion.
Simulation of Surface Water for Un‐Gauged Areas with Storage‐Attenuation Wetlands1
Authors: Said Ahmed , Ross Mark , Trout Ken , Zhang Jing
Published: March 2007

Abstract:  A nontraditional application of the Hydrological Simulation Program – FORTRAN (HSPF) model to simulate freshwater discharge to upper Charlotte Harbor along Florida’s west coast was performed. This application was different from traditional HSPF applications in three ways. First, the domain of the model was defined based on the hydraulic characteristics of the landforms using small distributed parameter discretization. Second, broad wetland land forms, representing more than 20% of this area, were simulated as reaches with storage‐attenuation characteristics and not as pervious land segments (PERLNDs). Finally, the reach flow‐tables (F‐Tables) were configured in a unique way to be calibrated representing the uncertainty of the storage‐attenuation process. Characterizing wetlands as hydrography elements allows flow from the wetlands to be treated as a stage‐dependent flux. The study was conducted for the un‐gauged portion of the Peace and Myakka rivers in west‐central Florida. Due to low gradient tidal influences, a large portion of the basin is un‐gauged. The objective of this study was to simulate stream flow discharges and to estimate freshwater inflow from these un‐gauged areas to upper Charlotte Harbor. Two local gauging stations were located within the model domain and were used for calibration. Another gauge with a shorter period of record was used for verification. A set of global hydrologic parameters were selected and tested using the parameter optimization software (PEST) during the calibration. Model results were evaluated using PEST and well‐known statistical indices. The correlation coefficients were very high (0.899 and 0.825) for the two calibration stations. Further testing of this approach appears warranted for watersheds with significant wetlands coverage.
Inferential and Non‐Inferential Reasoning
Authors: STREUMER BART
Published: March 2007

It is sometimes suggested that there are two kinds of reasoning: inferential reasoning and non‐inferential reasoning. However, it is not entirely clear what the difference between these two kinds of reasoning is. In this paper, I try to answer the question what this difference is. I first discuss three answers to this question that I argue are unsatisfactory. I then give a different answer to this question, and I argue that this answer is satisfactory. I end by showing that this answer can help to resolve some disagreements in which the difference between inferential and non‐inferential reasoning plays a role.
Compassionate Phenomenal Conservatism
Authors: HUEMER MICHAEL
Published: March 2007

I defend the principle of Phenomenal Conservatism, on which appearances of all kinds generate at least some justification for belief. I argue that there is no reason for privileging introspection or intuition over perceptual experience as a source of justified belief; that those who deny Phenomenal Conservatism are in a self‐defeating position, in that their view cannot be both true and justified; and that the demand for a metajustification for Phenomenal Conservatism either is an easily met demand, or is an unfair or question‐begging one.
Pretense, Existence, and Fictional Objects
Authors: EVERETT ANTHONY
Published: March 2007

There has recently been considerable interest in accounts of fiction which treat fictional characters as abstract objects. In this paper I argue against this view. More precisely I argue that such accounts are unable to accommodate our intuitions that fictional negative existentials such as “Raskolnikov doesn't exist” are true. I offer a general argument to this effect and then consider, but reject, some of the accounts of fictional negative existentials offered by abstract object theorists. I then note that some of the sort of data invoked by the abstract object theorist in fact cuts against her position. I conclude that we should not regard fictional characters as abstract objects but rather should adopt a make‐believe theoretic account of fictional characters along the lines of those developed by Ken Walton and others.
Justified Judging
Authors: BIRD ALEXANDER
Published: March 2007

Traditional approaches to epistemology have sought, unsuccessfully, to define knowledge in terms of justification. I follow Timothy Williamson in arguing that this is misconceived and that we should take knowledge as our fundamental epistemological notion. We can then characterise justification as a certain sort of approximation to knowledge. A judgement is justified if and only if the reason (if there is one) for a failure to know is to be found outside the subject’s mental states; that is, justified judging is possible knowing (where one world accessible from another if and only if they are identical with regard to a subject’s antecedent mental states and judgement forming processes). This view is explained and defended.
Descartes on the Dubitability of the Existence of Self
Authors: CUNNING DAVID
Published: March 2007

In a number a passages Descartes appears to insist that “I am, I exist” and its variants are wholly indubitable. These passages present an intractable problem of interpretation in the face of passages in which Descartes allows that any result is dubitable, “I am, I exist” included. Here I pull together a number of elements of Descartes’ system to show how all of these passages hang together. If my analysis is correct, it tells us something about the perspective that Descartes himself thinks we should take in reading the Meditations.
On the Phenomenon of “Dog‐Wise Arrangement”
Authors: ELDER CRAWFORD L.
Published: March 2007

An influential line of thought in metaphysics holds that where common sense discerns a tree or a dog or a baseball there may be just many microparticles. Provided the microparticles are arranged in the right way—are “treewise” or “dogwise” or “baseballwise” arranged—our sensory experiences will be just the same as if a tree or dog or baseball were really there. Thereforewhetherthere really are such familiar objects in the world can be decided only by determining whatmoreis needed for microparticles dogwise arranged actually tocomposea dog. This paper argues that this line of thought sets up the wrong agenda. Composition is trivial; dogwise (etc.) arrangement is tricky. Dogwise arrangement will obtain in the wrong regions unless we stipulate that there are dogs, and that dogwise arrangement obtains only within their borders. The bearers of dogwise arrangement, moreover, will have to be dogs themselves, not their microparticles. Thus allowing that dogwise arrangement obtains at all is allowing that there are dogs.
Response Scenario and Nonsmooth Features in the Nonlinear Dynamics of an Impacting Inverted Pendulum
Authors: Lenci Stefano , Demeio Lucio , Petrini Milena
Published: March 2007

In this work, we perform a systematic numerical investigation of the nonlinear dynamics of an inverted pendulum between lateral rebounding barriers. Three different families of considerably variable attractors—periodic, chaotic, and rest positions with subsequent chattering—are found. All of them are investigated, in detail, and the response scenario is determined by both bifurcation diagrams and behavior charts of single attractors, and overall maps. Attention is focused on local and global bifurcations that lead to the attractor-basin metamorphoses. Numerical results show the extreme richness of the dynamical response of the system, which is deemed to be of interest also in view of prospective mechanical applications.
Control of Impact Microactuators for Precise Positioning
Authors: Zhao Xiaopeng , Dankowicz Harry
Published: March 2007

Electrically driven impact microactuators generate nanoscale displacements without large driving distances and high voltages. These systems exhibit complex dynamics because of inherent nonlinearities due to impacts, friction, and electric forces. As a result, dramatic changes in system behavior, associated with so-called grazing bifurcations, may occur during the transition between impacting and nonimpacting dynamics, including the presence of robust chaos. For successful open-loop operating conditions, the system design is limited to certain parameter regions, where desired system responses reside. The objective of this paper is to overcome this limitation to allow for a more precise displacement manipulation using impact microactuators. This is achieved through a closed-loop feedback scheme that successfully controls the system dynamics in the near-grazing region.
Dynamic Modeling and Experimental Testing of a Piano Action Mechanism
Authors: Hirschkorn Martin , McPhee John , Birkett Stephen
Published: March 2007

A model for a grand piano action is proposed in this paper. The multibody dynamic model treats each of the five main action components (key, whippen, jack, repetition lever, and hammer) as a rigid body, and incorporates a contact model to determine the normal and friction forces at 13 locations between each of the contacting bodies. All parameters in the model are directly measured from experiments on individual action components, allowing the model to be used as a prototyping tool for actions that have not yet been designed or built. The behavior of the model was compared to the behavior of an experimental grand piano action and found to be very accurate for high force blows, and reasonably accurate for low force blows.