bluuebunny/crossref_metadata_2025_split huggingface dataset:
Measurement and analysis of health related quality of life and environmental data
Authors: Mesbah Mounir 
Published: July 2004

AbstractThe definition (or construction) of variables and indicators, and the analysis of the evolution of their joint distribution between various populations, times and areas are generally two different, well separated steps of the work for a statistician in the field of environment and/or health related quality of life.The first step generally deals with calibration and metrology of variables. Key words are measurement or scoring, depending on the area of application. Most of the time, the statistical methods used are exploratory. The kinds of models specified are generally structural: classical factorial analysis models or modern item response theory models. The second step is certainly more known by most inferential statisticians. Linear, generalized linear, time series and survival models are very useful models in this step, where the variables constructed in the first step are incorporated and their joint distribution with the other analysis variables (treatment group, time, duration of life, etc.) is investigated.In this article, the simple strategy of separating the two steps is compared with the global strategy of defining and analysing a global model, including both the measurement and the analysis step. Copyright © 2004 John Wiley & Sons, Ltd.
Assessing lung cancer risk in railroad workers using a first hitting time regression model
Authors: Ting Lee Mei‐Ling , Whitmore G. A. , Laden Francine , Hart Jaime E. , Garshick Eric 
Published: July 2004

AbstractThis article examines the application of a first hitting time (FHT) model, using an operational time scale, to assess mortality risk differentials of the work environment. A major case application is presented that applies the model to three job categories of railroad workers. The data set involves a study of more than 50 000 workers with mortality assessed from 1959 to 1996. Lung cancer mortality was assessed because of a suspected link to diesel exhaust exposure. Based on a model that stipulates that death occurs when the disease state of a subject first hits a threshold value, the FHT model provides insights into factors influencing disease progression. In this application, in particular, the findings suggest that a job category in 1959 alters the risk of death from lung cancer. Copyright © 2004 John Wiley & Sons, Ltd.
Smooth non‐parametric estimation of the distribution function from balanced ranked set samples
Authors: Gulati Sneh 
Published: July 2004

AbstractIn certain sampling schemes, such as ranked set sampling, the observed data set can consist entirely of independent order statistics. A balanced ranked set sample consists of n independent cycles, in each of which the experimenter selects k random samples, each of size k. The recorded observation in sample r of cycle i is the rth order statistic, X(r). Stokes and Sager (1988) have shown that the empirical distribution function based on such samples is an unbiased estimate of the underlying distribution function and is more precise than the empirical distribution function calculated from a simple random sample of the same size. In this article, the properties of the empirical distribution function developed by Stokes and Sager (1988) are further investigated. In addition, a kernel‐type estimator of the distribution function is developed. For large n, the smooth estimator is shown to be consistent and asymptotically normal. Finally, small sample properties of the two estimators are investigated and compared via computer simulations. Copyright © 2004 John Wiley & Sons, Ltd.
Using inter‐event functions for bandwidth selection in disease incidence ratio estimation
Authors: Chadæuf J. , Lebond A. , Senoussi R. 
Published: July 2004

AbstractWe propose a distance based criterion to choose the optimal bandwidth for a non‐parametric kernel estimator of the mark probability of a non‐stationary bivariate location process. The selected bandwidth achieves the minimum standardized distance between the observed inter‐event distance distribution and its expectation under the estimated model. This selection principle is performed to map the intensity of the incidence ratio of a West‐Nile outbreak in the South of France. Copyright © 2004 John Wiley & Sons, Ltd.
Assessment of sediment trace metal level and biological quality of Rhumel river by using multivariate analysis
Authors: Afri‐Mehennaoui Fatima‐Zohra , Sahli Leila , Mehennaoui Smail 
Published: July 2004

AbstractThe aim of this article is to assess the level of trace metal contamination of sediment and to evaluate the environmental water quality based on the distribution of benthic organisms at stations along the Rhumel river and its principal tributary Boumerzoug river selected in urban areas (Constantine, Algeria). Fresh sediment samples and benthic organisms were collected from 10 sites on three occasions (December 2000, February 2001 and April 2001). Four trace metals—manganese (Mn), lead (Pb), chrome (Cr), and cadmium (Cd)—were measured in surface sediment and in the fauna using a flame or flameless atomic absorption spectrophotometer. In addition, chemical water parameters, pH, dissolved oxygen (DO), conductivity (EC) and sediment variables, pH, loss on ignition (LOI) and grain size were determined. The differences in species composition of the benthic community and the biotic index variation were used to reveal disturbance in watercourses.Principal component analysis (PCA) was used to identify the relationship between the sediment variables, water chemistry and distribution of benthic invertebrate communities. The results of PCA indicate that there are several significant correlations between trace metals which suggest their common origin (anthropogenic or natural sources). Besides, the PCA results suggest the following trend: the biotic index, communities' distribution of macroinvertebrates and dissolved oxygen were unconnected to from both sediment and fauna trace metals concentrations. Copyright © 2004 John Wiley & Sons, Ltd.
New real‐value modal combination rules for non‐classically damped structures
Authors: Falsone Giovanni , Muscolino Giuseppe 
Published: July 2004

AbstractA procedure is presented to determine new modal combination rules (both CQC and SRSS) for non‐classically damped structures. The procedure presented in this paper does not need the solution of any complex eigenvalue problem, in contrast to other methods found in the literature. Thus, the modal combination rules presented here are easily applicable, even by those engineers who are unaccustomed to using complex algebra. Moreover, these formulations show the further advantage of requiring the response spectra only for the target damping ratio value. So the use of approximated formulae, necessary for passing from the response spectrum with the target damping ratio value to other ones, is avoided. Copyright © 2004 John Wiley & Sons, Ltd.
Evaluation of site‐dependent constant‐damage design spectra for reinforced concrete structures
Authors: Panyakapo Phaiboon 
Published: July 2004

AbstractAn investigation on the validity of the conventional design approach known as constant displacement ductility is carried out. The hysteretic behaviour described by the Modified Takeda model is taken to represent the characteristics of reinforced concrete structural systems. The results presented in the form of seismic damage spectra indicate that the conventional design approach may not be valid because cumulative damage is excessively high. The inelastic design spectra based on the constant‐damage concept are proposed in terms of simplified expressions. The expressions are derived from constant‐damage design spectra computed by non‐linear response analysis for SDOF systems subjected to ground motions recorded on rock sites, alluvium deposits, and soft‐soil sites. The proposed expressions, which are dependent on the local soil conditions, are functions of target seismic damage, displacement ductility ratio and period of vibration. The seismic damage of structures that have been designed based on this new design approach is also checked by a design‐and‐evaluation approach. The results are found to be satisfactory. Copyright © 2004 John Wiley & Sons, Ltd.
Modeling discontinuous periodic conditional volatility: Evidence from the commodity futures market
Authors: Taylor Nicholas 
Published: July 2004

AbstractThis paper examines a wide variety of models that allow for complex and discontinuous periodic variation in conditional volatility. The value of these models (including augmented versions of existing models) is demonstrated with an application to high frequency commodity futures return data. Their use is necessary, in this context, because commodity futures returns exhibit discontinuous intraday and interday periodicities in conditional volatility. The former of these effects is well documented for various asset returns; however, the latter is unique amongst commodity futures returns, where contract delivery and climate are driving forces. Using six years of high‐frequency cocoa futures data, the results show that these characteristics of conditional return volatility are most adequately captured by a spline‐version of the periodic generalized autoregressive conditional heteroscedastic (PGARCH) model. This model also provides superior forecasts of future return volatility that are robust to variation in the loss function assumed by the user, and are shown to be beneficial to users of Value‐at‐Risk (VaR) models. © 2004 Wiley Periodicals, Inc. Jrl Fut Mark 24:805–834, 2004
Romarchite and associated phases as common corrosion products on pewter artifacts from marine archaeological sites
Authors: Dunkle Stacie E. , Craig James R. , Lusardi Wayne R. 
Published: July 2004

AbstractCorrosion products were examined from typical pewter artifacts originating from six different submerged archaeological sites, dating to between ca. A.D. 1550 and 1733, along the eastern seaboard of North America and in the Caribbean Sea. The artifacts were viewed as 270–450‐year long experiments revealing the phases and mechanisms of tin corrosion in seawater. All of the samples analyzed exhibit abhurite (Sn3O(OH)2Cl2), romarchite (SnO), and hydroromarchite (Sn3O2(OH)2) forming at the expense of the underlying artifact. Textural analysis suggests that abhurite is the first alteration product to form at the expense of the pewter; romarchite subsequently develops and then hydroromarchite. The outermost corrosion layers on several of the most corroded artifacts also exhibit cassiterite (SnO2) as a significant and apparently final phase to form during alteration. The absence of this mineral on many samples demonstrates that, while samples appeared to be stable under the conditions that were present, cassiterite had not yet had time to form. The very limited stability field for romarchite, based on data presented by Séby et al. (Geochimica et Cosmochimica Acta, 65, 3041–3053, 2001), suggests that its presence on these artifacts may be the result of a kinetic effect. The universal appearance of this mineral on corroding tin suggests that it is a required step in the oxidation of pure tin to the final most stable phase of cassiterite. The stability of romarchite and its effectiveness as an agent of passivation can provide insight into not only the formation of tin oxides but the rate of tin corrosion. This can have significant implications in the field of artifact preservation as well as more widespread industrial applications. © 2004 Wiley Periodicals, Inc.
Geoarchaeology and prehistory of the Kipsing and Tol river watersheds in the Mukogodo Hills region of Central Kenya
Authors: Pearl Frederic B. , Dickson D. Bruce 
Published: July 2004

AbstractAn archaeological survey and geomorphological investigation were conducted over a period of three years in the Tol and Kipsing River valleys, both located in the Mukogodo Hills‐Upper Ewaso Ng'iro Plains region of Central Kenya. Eleven alluvial‐stratigraphic sections were studied, and five late‐Quaternary alluvial stratigraphic units were identified on the basis of lithology, chronology, and soil stratigraphy. The locations of 63 archaeological sites recorded during the reconnaissance were compared with the distribution of the alluvial units. These data were used to predict where sites of different cultural periods are most likely to be found and to determine the relationship between site location and alluvial deposition. Since natural processes of deposition and erosion do not fully account for the distribution of Middle and Later Stone Age sites in the study area, the hypothesis that these differences reflect human choices, not the operation of natural processes, cannot be rejected. © 2004 Wiley Periodicals, Inc.
Late holocene behavior of Chaco and McElmo Canyon drainages (Southwest U.S.): A comparison based on archaeologic age controls
Authors: Force Eric R. 
Published: July 2004

AbstractTwo outwardly similar shallow‐canyon drainages of the Four Corners region of the Colorado Plateau (southwestern U.S.), McElmo Creek (SW Colorado) and Chaco Wash (NW New Mexico), expose late Holocene units which have been dated by numerous remains of the puebloan Anasazi culture (A.D. 500–1300). The stratigraphic sequences, though composed of similar sediment facies, show markedly different evolutions. The McElmo Canyon sequence consists of two units separated by an unconformity that apparently represents an arroyo that migrated 5 km upstream in 200 years, suggesting a slow “complex response” model. The dated Chaco Canyon sequence includes an arroyo channel fill seemingly cut simultaneously through a 9–14 km reach, which began filling simultaneously throughout about 100 years later. Base level control seems to have been temporarily controlled by a large eolian sand dune damming Chaco Wash, probably during a dry period. The two entrenchment chronologies do overlap, but the resemblance of either record to published regional chronostratigraphies is minimal. The differences among these regional chronologies suggest that great variety existed among fluvial sequences in prehistory, perhaps more than is seen in present‐day drainages of the region. The contrasting fluvial histories correspond to an equally marked difference in cultural responses, especially in water‐control technology. The strongest obvious similarity between the sequences is probable anthropogenic influence, which is a consequence of using cultural remains for establishing chronological control. A strong influence of climate change is less obvious but still probable if lags in the system and possible intraregional paleoclimatic differences are included in the analysis. © 2004 Wiley Periodicals, Inc.
Hypoxic regulation of Ca2+ signaling in cultured rat astrocytes
Authors: Smith I.F. , Boyle J.P. , Kang P. , Rome S. , Pearson H.A. , Peers C. 
Published: July 2004

AbstractAcute hypoxia modulates various cell processes, such as cell excitability, through the regulation of ion channel activity. Given the central role of Ca2+ signaling in the physiological functioning of astrocytes, we have investigated how acute hypoxia regulates such signaling, and compared results with those evoked by bradykinin (BK), an agonist whose ability to liberate Ca2+ from intracellular stores is well documented. In Ca2+‐free perfusate, BK evoked rises of [Ca2+]i in all cells examined. Hypoxia produced smaller rises of [Ca2+]i in most cells, but always suppressed subsequent rises of [Ca2+]i induced by BK. Thapsigargin pre‐treatment of cells prevented any rise of [Ca2+]i evoked by either BK or hypoxia. Restoration of Ca2+ to the perfusate following a period of acute hypoxia always evoked capacitative Ca2+ entry. During mitochondrial inhibition (due to exposure to carbonyl cyanide p–trifluromethoxyphenyl hydrazone (FCCP) and oligomycin), rises in [Ca2+]i (observed in Ca2+‐free perfusate) evoked by hypoxia or by BK, were significantly enhanced, and hypoxia always evoked responses. Our data indicate that hypoxia triggers Ca2+ release from endoplasmic reticulum stores, efficiently buffered by mitochondria. Such liberation of Ca2+ is sufficient to trigger capacitative Ca2+ entry. These findings indicate that the local O2 level is a key determinant of astrocyte Ca2+ signaling, likely modulating Ca2+‐dependent astrocyte functions in the central nervous system. © 2004 Wiley‐Liss, Inc.
Low nuclear levels of nuclear factor‐κB are essential for KC self‐induction in astrocytes: Requirements for shuttling and phosphorylation
Authors: Zhai Qiwei , Luo Yi , Zhang Ye , Berman Michael A. , Dorf Martin E. 
Published: July 2004

AbstractStimulation with the chemokine KC induces an autocrine response in mouse astrocytes. A requirement for NF‐κB was established for KC self‐induction. NF‐κB inhibitors, p65 antisense oligonucleotides, or dominant‐negative IκBα inhibited this autocrine response. Mutation of a specific κB site in the KC promoter also blocked KC self‐induction. Chromatin immunoprecipitation and in vivo footprinting confirmed the direct binding of NF‐κB to the KC promoter. However, neither NF‐κB nuclear translocation, increased IκB degradation, nor upregulation of NF‐κB DNA binding activity was observed after KC stimulation. Reporter gene assays demonstrated KC‐upregulated NF‐κB transcriptional activity, and this effect was inhibited by dominant‐negative IκBα. Accumulation of NF‐κB was noted within the nucleus in the presence of nuclear export inhibitor leptomycin B, demonstrating constitutive shuttling of NF‐κB between the cytoplasm and nucleus. Blocking NF‐κB shuttling inhibited KC transcription. KC induced p65 phosphorylation, which was critical for NF‐κB activation as determined with the Gal‐4‐p65 fusion protein and mutation of p65 phosphorylation sites. In conclusion, low‐level nuclear NF‐κB is essential for KC self‐induction, and this effect is mediated by shuttling and phosphorylation of NF‐κB. The results outline a novel mechanism for NF‐κB participation in transcription regulation. © 2004 Wiley‐Liss, Inc.
Shaker‐type potassium channel subunits differentially control oligodendrocyte progenitor proliferation
Authors: Vautier François , Belachew Shibeshih , Chittajallu Ramesh , Gallo Vittorio 
Published: July 2004

AbstractOligodendrocyte precursor (OP) cells are exposed to multiple extrinsic signals that control their proliferation and differentiation. Previous cell proliferation studies and electrophysiological analysis in cultured cells and in brain slices have suggested that outward potassium channels, particularly Kv1 subunits, may have a prominent role in OP cell proliferation. In the present study, we assessed to what extent overexpression of Kv1.3, Kv1.4, Kv1.5, and Kv1.6 can affect OP cell proliferation and differentiation in culture. We observed that overexpression of Kv1.3 or Kv1.4 increased OP cell proliferation in the absence of mitogens, whereas Kv1.6 overexpression inhibited mitogen‐induced OP cell cycle progression. Interestingly, Kv1.3, Kv1.4, Kv1.5, and Kv1.6 overexpression did not interfere with the kinetics of oligodendrocyte differentiation. This study represents the first demonstration that the activity of potassium channels containing distinct Kv1 subunit proteins directly controls oligodendroglial proliferation in the presence of mitogens, as well as in growth factor‐free conditions. © 2004 Wiley‐Liss, Inc.
Astroglial‐derived lymphotoxin‐α exacerbates inflammation and demyelination, but not remyelination
Authors: Plant Sheila R. , Arnett Heather A. , Ting Jenny P‐y. 
Published: July 2004

AbstractTumor necrosis factorα (TNFα) and lymphotoxin‐α (Ltα) are upregulated in and around multiple sclerosis plaques and are proposed to play a role during chronic inflammation in demyelinating disease. Despite the perceived detrimental role of these cytokines, human clinical trials inhibiting TNFα signaling has led to worsening of symptoms in multiple sclerosis (MS) patients. Our laboratory has verified a role for TNFα in the exacerbation of demyelination but, more importantly, has demonstrated a novel role for TNFα in reparative remyelination in a cuprizone‐induced demyelination model. This may explain the worsening of symptoms experienced by MS patients. In view of the cross‐talk in TNF family signaling, the aim of this study is to understand the role of Ltα in demyelination and remyelination in hopes of improving therapeutic strategies for MS. Using the same model, we show that mice lacking Ltα exhibit a delay in demyelination that is greater than that exhibited by TNFα null mice. In this model, Ltα is expressed primarily by astroglia. The delay in demyelination is accompanied by a delay in the loss of mature GSTπ‐positive oligodendrocytes in Ltα−/− mice compared with wild‐type mice. Ltα−/− mice have decreased numbers of microglia at the site of insult during demyelination, although the number of astrocytes present is similar between strains. In contrast to TNFα the lack of Ltα did not alter the time course of remyelination, or the number of mature oligodendrocytes during the remyelination phase. Since Ltα is detrimental in inflammation and demyelination, but not necessary for remyelination and repair, inhibiting Ltα signaling may represent a promising strategy to treat MS. © 2004 Wiley‐Liss, Inc.
Murine complement C4 is not required for experimental autoimmune encephalomyelitis
Authors: Boos Laura A. , Szalai Alexander J. , Barnum Scott R. 
Published: July 2004

AbstractIn vitro studies have demonstrated that myelin and myelin‐derived proteins activate both the classical and alternative complement pathways. More recently, studies have shown that mice deficient in factor B, a protein required for activation of the alternative pathway, have attenuated experimental autoimmune encephalomyelitis (EAE), the animal model for multiple sclerosis. The relative contribution of the classical pathway to the pathogenesis of EAE has remained unexplored. To address this question, we performed EAE using mice deficient in C4 (C4−/−), a protein required for full activation of the classical pathway. We found that deletion of the C4 gene does not significantly change either the time of onset or the severity and tempo of myelin oligodendrocyte‐induced EAE compared with controls with a fully intact complement system. We observed similar levels of cellular infiltration (CD11b+ macrophages and CD3+ T cells) and demyelination in the two kinds of mice. Despite this, ribonuclease protection assays demonstrated a two‐ to fourfold increase in several pro‐inflammatory cytokines in C4−/− mice with EAE, including interleukin‐β (IL‐1β), IL‐18, tumor necrosis factor‐α (TNF‐α), IP‐10, and RANTES. These results support the conclusion that the contribution of murine complement to the pathogenesis of demyelinating disease is realized via the alternative pathway. © 2004 Wiley‐Liss, Inc.
Subjective and polysomnographic effects of milnacipran on sleep in depressed patients
Authors: Lemoine Patrick , Faivre Thierry 
Published: July 2004

AbstractThe effects of milnacipran (50 mg bid) on sleep patterns of eight depressed inpatients, treated for 4 weeks, were studied during the initial (days 1–3) and terminal (days 26–28) treatment periods and compared with those obtained from three sleep recordings performed just prior to the initiation of the treatment. The clinical evolution of patients was evaluated weekly using the MADRS depression scale and the Spiegel and Norris sleep scales. Clinical improvement, shown by a mean reduction of 58% in MADRS scale scores, was accompanied by an improvement of disturbed sleep parameters. From the beginning of treatment, there was an increase in the total duration of sleep and stage II sleep, a decrease in sleep latency and an increase in sleep efficiency. Total REM sleep was not modified although, since there was an increase in total sleep time, the percent REM sleep was significantly reduced. REM latency was increased early in the study, an effect classically associated with antidepressant treatment. This study suggests that milnacipran improves disturbed sleep parameters in depressed patients without any additional disturbance at the onset of treatment. Copyright © 2004 John Wiley & Sons, Ltd.