bluuebunny/crossref_metadata_2025 huggingface dataset:
Pedagogical context knowledge: Toward a fuller understanding of what good science teachers know
Authors: Barnett John , Hodson Derek
Published: August 2002

A codified model of teacher knowledge, situated in school science teaching, is proposed as a synthesis of a number of models, metaphors, and notions already described in the literature about teachers' knowledge. This model, called pedagogical context knowledge, suggests that in discussion of their classroom practice, exemplary science teachers utilize four kinds of knowledge: academic and research knowledge, pedagogical content knowledge, professional knowledge, and classroom knowledge. The model is used to examine data collected through interviews with science teachers about the ways in which they design and implement science lessons. Analysis of the data shows that the model is sufficiently robust to provide a simple and rapid, yet effective and efficient way of examining teachers' views and the knowledge base in which they are embedded. © 2001 John Wiley & Sons, Inc. Sci Ed 85:426–453, 2001.
A network switch for supporting high‐performance parallel processing by computers distributed in local areas
Authors: Nishi Hiroaki , Tasho Koji , Kudoh Tomohiro , Amano Hideharu
Published: August 2002

The authors have developed a communications architecture called RHiNET that is capable of high‐performance parallel processing by interconnecting PCs and WSs. RHiNET uses not only computers concentrated in one place but also computers used for daily business within buildings and within floors for parallel processing. Networks used by RHiNET should have high effective bandwidths and small latencies for high‐efficiency computing, as well as link lengths for connecting the computers within buildings and floors and a free topology. The former requirements are not satisfied sufficiently by the conventional LANs, while the latter is not satisfied by SANs which are used in cluster systems. RHiNET satisfies both conditions by using a switch having a large memory capacity. In this paper, the architecture and implementation of the RHiNET/SW1 switch used by RHiNET networks are discussed. A scheme called virtual cache is used in RHiNET/SW1 such that a large‐capacity packet buffer is installed by SRAM outside the switch ASIC. In addition, the performance of the switch is evaluated by a simulator. © 2001 Scripta Technica, Syst Comp Jpn, 32(14): 24–33, 2001
Image correspondences by warping functions and its applications
Authors: Prochazka Zdenek , Ito Takayuki , Okamoto Toshio
Published: August 2002

In various fields such as movement detection, stereo matching, image morphing, image synthesis, and image recognition, automatic determination of the image correspondence is a very basic problem. In this paper, the relation establishing correspondence between a prototype and the images (i.e., warping function) is treated and the method of determination of such function is proposed. The proposed method is based on the variational principle. The warping function is determined as the solution which minimizes the brightness differences between the pixels under smoothness constraints. Examples on applications of the proposed procedure of determination of warping functions are presented which indicate the effectiveness of the method. ©2002 Scripta Technica, Syst Comp Jpn, 33(2): 22–30, 2002
Image processing of snow particles and classification into snowflakes and graupel
Authors: Shiina Toru , Muramoto Ken‐ichiro
Published: August 2002

To analyze the relationship between the radar reflectivity and the intensity of a snowfall, it is important to know the percentages of snowflakes and graupel in snow particles. This paper proposes an automatic method of classification of falling snow particles. The method consists of two CCD cameras which record each particle simultaneously with different shutter speeds and magnifications. The first CCD camera has a slow shutter speed (1/60 s) and a relatively wide view angle, and records the trailing image and diameter of each falling snow particle so that its fall velocity is obtained, and this camera also records the distribution of diameters of the snow particles. The second CCD camera has a higher shutter speed (1/8000 s) and a narrow view field (1/5 the first CCD camera), and records a binary image and a gray‐level image of each snow particle so that the shape parameter of each particle can be obtained. Each snow particle is classified as a snowflake or a graupel pellet by image processing based on the fall velocity and shape parameter. The proposed method has been successfully tested in snowfall (continuously for 2 weeks), obtaining the percentages of snowflakes and graupel once a minute in real time. © 2002 Scripta Technica, Syst Comp Jpn, 33(2): 43–53, 2002
Void dwellings—a ‘headline’ indicator?
Authors: Tate John
Published: August 2002

This paper explores a specific theme within the context of the use of ‘headline’ indicators by the UK strategy on sustainable development. It argues that the indicator on housing (unfit dwellings) might appropriately be replaced by a measure relating to void (empty) dwellings. Following an interpretation of what constitutes a ‘headline’ indicator, the paper explores the role of such an indicator in assessing the sustainability of the housing system in terms of the respective roles played by both unfit and void dwellings. The argument is then expanded through an examination of current issues and initiatives in relation to void dwellings, including abandonment in the core areas of some cities and falling demand in the social housing sector generally. The implications for the environment of poor management of the housing stock are stressed, as are the linkages between man‐made and natural systems. Failure to address the issues raised could result in a ‘lose–lose’ situation with unsustainable outcomes for both urban and rural environments. The void dwelling measure is superior to that of unfits on a range of counts, but particularly if this wider context is taken into consideration. Copyright © 2002 John Wiley & Sons, Ltd. and ERP Environment.
High‐mass‐resolution ToF‐SIMS study of chlorine‐containing polymers
Authors: Briggs David , Fletcher Ian W. , Gonçalves Nancy M.
Published: August 2002

A series of seven chlorine‐containing polymers with widely ranging structures have been studied by time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS) at high mass resolution. The prototypical positive ion spectrum of poly(vinyl chloride) has been analysed in detail to identify unambiguously all the components at each nominal mass up to m/z 130. For other polymers based on variously Cl‐substituted aliphatic hydrocarbons, the same Cl‐containing ions are observed but their relative intensities are different and characteristic. The relative intensities of common fragments containing one or two chlorine atoms in both positive ion spectra (RCl2+/RCl+) and negative ion spectra (Cl2−/Cl−) have been compared quantitatively with the bulk atomic chlorine concentration. These two ratios also show a remarkable correlation across the polymer series. An ion formation mechanism is proposed to explain the observed correlations. Copyright © 2002 John Wiley & Sons, Ltd.
Spatial mixture relative risk models applied to disease mapping
Authors: Lawson Andrew B. , Clark Allan
Published: August 2002

An important issue within health services research is the correct allocation of resources within health authority regions and the capability of public health professionals to make such allocation appropriately. This allocation is often based on a mapping of relevant disease incidence and the assessment of the geographical distribution of relative risk of disease in small areas within the health authority administrative domain. Existing methods for the statistical analysis of small area risk are mostly based on smoothing methods. However, these methods often smooth over large discontinuities in the risk surface which might be important to maintain for the purposes of resource allocation. In this paper we propose a method that involves the use of spatial mixtures of components that can provide a balance between smoothness and the maintenance of discontinuity. The method is applied to a sudden infant death incidence data set. Copyright © 2002 John Wiley & Sons, Ltd.
A new parametric method based on S‐distributions for computing receiver operating characteristic curves for continuous diagnostic tests
Authors: Sorribas Albert , March Jaume , Trujillano Javier
Published: August 2002

Receiver operating characteristic (ROC) curves provides a method for evaluating the performance of a diagnostic test. These curves represent the true positive ratio, that is, the true positives among those affected by the disease, as a function of the false positive ratio, that is, the false positives among the healthy, corresponding to each possible value of the diagnostic variable. When the diagnostic variable is continuous, the corresponding ROC curve is also continuous. However, estimation of such curve through the analysis of sample data yields a step‐line, unless some assumption is made on the underlying distribution of the considered variable. Since the actual distribution of the diagnostic test is seldom known, it is difficult to select an appropriate distribution for practical use. Data transformation may offer a solution but also may introduce a distortion on the evaluation of the diagnostic test. In this paper we show that the distribution family known as the S‐distribution can be used to solve this problem. The S‐distribution is defined as a differential equation in which the dependent variable is the cumulative. This special form provides a highly flexible family of distributions that can be used as models for unknown distributions. It has been shown that classical statistical distributions can be represented accurately as S‐distributions and that they occur in a definite subspace of the parameter space corresponding to the whole S‐distribution family. Consequently, many other distributional forms that do not correspond to known distributions are provided by the S‐distribution. This property can be used to model observed data for unknown distributions and is very useful in constructing parametric ROC curves in those cases. After fitting an S‐distribution to the observed samples of diseased and healthy populations, ROC curve computation is straightforward. A ROC curve can be considered as the solution of a differential equation in which the dependent variable is the ratio of true positives and the independent variable is the ratio of false positives. This equation can be easily obtained from the S‐distributions fitted to observed data. Using these results, we can compute pointwise confidence bands for the ROC curve and the corresponding area under the curve. We shall compare this approach with the empirical and the binormal methods for estimating a ROC curve to show that the S‐distribution based method is a useful parametric procedure. Copyright © 2002 John Wiley & Sons, Ltd.
Optimal two‐stage designs for clinical trials based on safety and efficacy
Authors: Thall Peter F. , Cheng Su‐Chun
Published: August 2002

In clinical trials designed to evaluate treatment efficacy, it is common practice to terminate a treatment arm in which the observed rate of an adverse event is unacceptably high. This practice may be formalized by a group‐sequential test based on a multivariate outcome including both adverse and efficacy events. Recently, Thall and Cheng proposed a family of tests for randomized trials of an experimental treatment versus a standard where patient outcome is bivariate with entries characterizing efficacy and safety. The test is motivated by the idea that clinically meaningful improvements over the standard may be characterized by a two‐dimensional parameter quantifying trade‐offs between efficacy and safety. We provide optimal two‐stage designs based on this test that minimize either the mean sample size under the null hypothesis of no treatment difference, or the maximum sample size if the trial continues to a second stage. A more general group‐sequential version of the design also is described, an illustration is provided, and application to the special case of single‐arm phase II trials is discussed. Copyright © 2001 John Wiley & Sons, Ltd.
Theory and practice in medical statistics
Authors: Armitage Peter
Published: August 2002

The discipline of statistics generally, and that of medical statistics in particular, has evolved through two traditions, the theoretical and the practical. Their history, traced briefly here, shows recurrent points of contact and a process of gradual merging which is now almost complete. However, the current tendency to build complex mathematical and computing models may lead to over‐confidence in their conclusions, when some crucial aspects of the data cannot easily be modelled satisfactorily. Illustrations are drawn from the use of formal stopping rules in the monitoring of clinical trials, and from the treatment of missing data and incomplete compliance with the trial protocol. Copyright © 2001 John Wiley & Sons, Ltd.
Disease map reconstruction
Authors: Lawson Andrew B.
Published: August 2002

The analysis of the geographical distribution of disease incidence or prevalence is now of considerable importance for public health workers and epidemiologists alike. Important disease variations often have a spatial expression and so spatial analysis methods are an important additional tool in this connection. In this tutorial I have aimed to highlight the main issues relating to the analysis of disease where the goal is the reduction in noise in a disease map. This area is sometimes simply called disease mapping. A number of modelling approaches to disease mapping are considered and a case study highlighting the methods advocated is also included. Copyright © 2001 John Wiley & Sons, Ltd.
Population toxicokinetic analysis of 2,3,7,8‐tetrachlorodibenzo‐p‐dioxin using Bayesian techniques
Authors: Bortot Paola , Thomaseth Karl , Salvan Alberto
Published: August 2002

Understanding the kinetics of 2,3,7,8‐tetrachlorodibenzo‐p‐dioxin (TCDD) concentrations in humans is an important step for TCDD cancer risk assessment. In this paper longitudinal series of serum TCDD concentration measurements on U.S. veterans of the Vietnam war, who were exposed to dioxin during herbicide‐spraying operations, are studied. The overall aim is to use these data to infer the dynamics of TCDD concentrations in humans. This is done by identifying a kinetic model describing the dioxin time course at the individual level. The individual toxicokinetic model is then expanded into a population model within a Bayesian hierarchical framework which allows residual variations across subjects that cannot be explained by observed covariates. Other complications in the data, such as unknown exposure histories, are also resolved implicitly through the hierarchical model. Moreover, the choice of a Bayesian approach enables the accumulation of external source of information in the form of prior distributions. The model is subjected to various diagnostic checks and analyses of sensitivity to distributional assumptions showing a good fit in terms of both the population and the kinetic features. Copyright © 2002 John Wiley & Sons, Ltd.
An isomorphic theory of stress: the dynamics of person–environment fit
Authors: Quick James Campbell , Nelson Debra L. , Quick Jonathan D. , Orman Dusty K.
Published: August 2002

An isomorphic theory in the domain of stress refers to a dimension‐specific extension of person–environment fit theory. Isomorphism extends person–environment fit theory by focusing attention on corresponding characteristics in the person and the environment; in this case, the control, uncertainty, and interpersonal dimensions. Isomorphic theory overarches and integrates the ecological and adaptation approaches to stress, providing the basis for a dynamic effects model of stress and person–environment fit. Copyright © 2001 John Wiley & Sons, Ltd.
Branded interface toolkits
Authors: Kotula Jeffrey
Published: August 2002

Typical software companies want the applications they market to have a consistent look and feel, so as to brand or identify their particular family of products or product line. Current user interface (UI) implementation techniques serve this business need poorly, tending to treat each application as a unique, independent artifact sharing little, if any, UI implementation code with other applications. Coupled with the overwhelming complexity found in modern UI toolkits, this results in unnecessarily high development costs for interfaces, and is at odds with the need of software companies to devote their resources to value‐added application code rather than incidental user‐interface implementation. This paper presents a model for a domain‐based UI application framework that addresses these issues: consistency in a family of products, both in operation and presentation; reduced implementation costs; and rapid development times. Copyright © 2001 John Wiley & Sons, Ltd.
The DeltaUp constraint solver: minimizing the number of method selections in DeltaBlue
Authors: Suzuki Tetsuya , Tokuda Takehiro
Published: August 2002

We present a modification of the DeltaBlue constraint solver called DeltaUp. DeltaBlue is an incremental constraint solver based on local propagation, which is widely used for constructing graphical user interfaces and algorithm animations. DeltaUp minimizes the number of time‐consuming tasks of DeltaBlue, namely method selections, in each planning phase. To compute the exact number of needed method selections, we introduced a cost function up‐cost to DeltaBlue. Our benchmarks show that DeltaUp is approximately two times faster than DeltaBlue in the best case. Even in the worst case, it is only slightly slower than DeltaBlue. Copyright © 2001 John Wiley & Sons, Ltd.
Revisiting the Model Minority Stereotype: Implications for Student Affairs Practice and Higher Education
Authors: Suzuki Bob H.
Published: August 2002

The model minority stereotype of Asian Americans is retrospectively analyzed twenty‐five years after the author’s original study of this issue. The continuing effects of this stereotype in higher education are examined.
MR imaging: Breast cancer staging and screening
Authors: Kinkel Karen , Vlastos Georges
Published: August 2002

This review describes the current knowledge and challenges of breast cancer staging and screening with MRI of the breast. Assessment of local disease extent, including tumor size, multicentricity, and chest wall invasion, can be obtained more accurately with MRI than with mammography. Moreover, international experts have established standardized reporting of MRI staging results, taking into account tumor size measurements and the number of breast quadrants involved. Results from MRI assessment of the axilla and skin are promising, but need further refinement. Preliminary results of the use of breast MRI in patients at high risk for breast cancer demonstrated a superiority of breast MRI over the combined use of mammography and high‐frequency ultrasound. The role of MRI in this subset of patients may be confirmed by ongoing larger multicenter trials. Strict protocol conditions are mandatory to maintain a high standard of quality. Confirming the nature of “MRI‐only” lesions with MRI‐guided biopsy systems will allow changes in treatment planning. More accurate tumor diagnosis and tumor volume evaluation may allow minimally invasive treatment strategies. Semin. Surg. Oncol. 20:187–196, 2001. © 2001 Wiley‐Liss, Inc.
Surgical strategies and minimal residual disease detection
Authors: Weitz Jürgen , Herfarth Christian
Published: August 2002

The ultimate goal in the treatment of cancer patients is the elimination of all tumor cells. A cure by surgery alone is possible only if the tumor is still confined locally. Detection of disseminated tumor cells may help to individually tailor the surgical procedure to each patient: extended or limited resections may be indicated depending on the individual state of tumor cell dissemination. In cases of systemic tumor cell dissemination, surgery alone cannot cure the patient. Thus, by detecting disseminated tumor cells, patients with a higher risk for relapse, who might benefit from multimodal therapeutic regimes, could be defined. A second aspect is the possibility of tumor cell shedding induced by manipulation during surgical procedures, which could be demonstrated for several tumor entities. Intraoperative tumor cell dissemination could be prevented by alternative operative strategies. In addition, perioperative antibody or cytotoxic therapy may prevent tumor cell implantation. Well‐designed clinical studies are now of major importance to evaluate the clinical impact of individualized patient management and altered surgical procedures. Semin. Surg. Oncol. 20:329–333, 2001. © 2001 Wiley‐Liss, Inc.
Effects of vibrissae removal on methamphetamine‐induced damage to rat somatosensory cortical neurons
Authors: O'Dell Steven J. , Marshall John F.
Published: August 2002

Repeated methamphetamine (mAMPH) damages forebrain monoamine terminals and causes degeneration of nonmonoaminergic cell bodies in rat primary somatosensory cortex (S1). These degenerating cortical neurons can be labeled with the fluorochrome dye Fluoro‐Jade (FJ) and are found almost exclusively in layers II/III and IV of the vibrissae representation in S1. Within S1, layer IV is organized into discrete, anatomically identifiable units termed barrels, each of which receives information from a single whisker. We previously reported that mAMPH‐damaged neurons in S1 were located within the whisker barrels, suggesting that the prolonged mAMPH‐induced whisking contributes to S1 neuronal injury. Here, we investigate effects of vibrissae removal on mAMPH‐induced damage to S1 neurons. Rats were anesthetized and vibrissae were trimmed from either the left, right, or neither side of the snout. The next day they were given four injections of either saline (1 ml/kg, s.c.) or mAMPH (4 mg/kg, s.c.) at 2‐h intervals. Three days later, cortical sections were processed for FJ histochemistry. The hemivibrissotomy produces a hemispheric asymmetry in FJ‐positive neurons in barrel cortex, with fewer damaged neurons contralateral than ipsilateral to whisker removal. Taken together with the demonstration that acute injection of this dose of mAMPH induces the immediate early gene zif/268 and Fos protein in barrel cortex, these data suggest that the prolonged behavioral activity involving the vibrissae contributes to the mAMPH‐induced damage to S1 neurons. Thus, some of the injurious effects of drugs may depend on afferent activity occurring as a result of the abnormal behaviors evoked by their administration. Synapse 43:122–130, 2002. © 2001 Wiley‐Liss, Inc.
In vitro and in vivo characterization of [125I]iodomethyllycaconitine in the rat
Authors: Navarro H.A. , Xu H. , Zhong D. , Abraham P. , Carroll F.I.
Published: August 2002

The in vitro and in vivo binding characteristics of [125I]iodomethyllycaconitine ([125I]iodoMLA) were determined in the rat. [125I]iodoMLA binding to rat cerebral cortex membranes was saturable and reversible and its specific binding represented approximately 70–80% of the total binding. [125I]iodoMLA labeled a single site with Kd = 1.8 ± 0.4 nM and Bmax = 68 ± 3 fmol/mg protein. Kinetic analysis revealed a t1/2 for association and dissociation of 10.5 ± 3.1 and 10.3 ± 1.6 min, respectively. Pharmacological characterization of [125I]iodoMLA binding indicated that it was specific for the α7 nAChR. In vitro brain region binding studies revealed greater binding in regions known to contain high numbers of α7 nAChRs. The analysis of the biodistribution of intravenously administered [125I]iodoMLA indicated that it was rapidly cleared and exhibited poor brain penetration; nevertheless, the levels of [125I]iodoMLA in α7 nAChR‐rich target regions were significantly increased compared to the nontarget region (cerebellum) 60–120 min after administration. No metabolism of MLA by human liver S9 fraction was detected. Our results suggest that [125I]iodoMLA will be a useful radioligand to study the α7 nAChR in vitro and in vivo. Synapse 44:117–123, 2002. © 2002 Wiley‐Liss, Inc.
Influence of restraint stress on the expression and the serine/threonine phosphatase activity of calcineurin in the rat brain
Authors: Takahashi Jun , Tanaka Kazuhide , Morinobu Shigeru , Fujimaki Koichiro , Li Sheng‐Tian , Kato Kunio , Ohkawa Masako , Yamawaki Shigeto , Kato Nobumasa
Published: August 2002

To investigate the role of calcineurin (CaN) in the pathogenesis of stress‐related psychiatric disorders, we examined the expression of CaN A mRNA and the serine/threonine phosphatase activity of CaN in the rat brain following various restraint stress paradigms. Northern blot analysis revealed no significant changes in the levels of CaN A mRNA expression, in either the frontal cortex or the hippocampus, in response to a single restraint stress for either 15, 45, or 90 min. In addition, no significant change in the levels of CaN A mRNA was found 3 or 6 h after a single restraint stress for 90 min. In situ hybridization analysis revealed that a single restraint stress for 45 min had no influence on CaN A mRNA expression in the CA1 and CA3 pyramidal cell layers or in the dentate gyrus granule cell layer of the hippocampus. However, serine/threonine phosphatase activity was significantly increased in both regions in response to a single restraint stress for either 45 or 90 min. These results demonstrate that the single restraint stress paradigms used in this study increase the activity of CaN without any changes in the expression of CaN, suggesting that the activation of calmodulin and the increased levels of heat shock proteins in response to the restraint stress may upregulate the activity of CaN in the rat brain. Synapse 40:130–136, 2001. © 2001 Wiley‐Liss, Inc.
Genotoxic action of the sesquiterpene lactone centratherin on mammalian cells in vitro and in vivo
Authors: Burim Regislaine Valéria , Canalle Renata , Lopes João Luis Callegari , Vichnewski Walter , Takahashi Catarina Satie
Published: August 2002

Centratherin is a sesquiterpene lactone known for its antimicrobial, anti‐inflammatory, and trypanocidal activities. The aim of this study was to determine the clastogenic and cytotoxic potential of centratherin in human lymphocytes and in mice. Human lymphocytes in culture were submitted to either continuous treatment or treatment during G2 phase of the cell cycle. After continuous treatment the 0.2 μg/ml concentration induced a significant increase in total of chromosomal aberrations (CA) and sister chromatid exchange compared to control, and it reduced the mitotic index (MI). In the treatment during G2 phase, centratherin induced a significant increase in the frequency of CA for all concentrations tested (0.1, 0.3, and 0.5 μg/ml). In the in vivo test system all three concentrations tested in mice (3.3, 6.7, and 13.3 mg/kg b.w.) induced a significant increase in CA compared to the negative control. On the basis of these results, centratherin showed clastogenic and cytotoxic activity on in vitro and in vivo mammalian systems. Teratogenesis Carcinog. Mutagen. 21:383–393, 2001. © 2001 Wiley‐Liss, Inc.
Green organic syntheses: Organic carbonates as methylating agents
Authors: Tundo Pietro , Perosa Alvise
Published: August 2002

Dimethylcarbonate (DMC) is a valuable methylating reagent that can replace methyl halides and dimethylsulfate in the methylation of a variety of nucleophiles. It couples tunable reactivity and unprecedented selectivity towards mono‐C‐ and mono‐N‐methylation. In addition, it is a prototype example of a green reagent, because it is nontoxic, is made by a clean process, is biodegradable, and reacts in the presence of a catalytic amount of base, thereby avoiding the formation of undesirable inorganic salts as by‐products. Depending on the reaction conditions, DMC can be reacted under plug‐flow, CSTR, or batch conditions. Other remarkable reactions are those where DMC behaves as an oxidant. The reactivity of other carbonates is reported as well. © 2002 The Japan Chemical Journal Forum and John Wiley & Sons, Inc. Chem Rec 2: 13–23, 2002
Toxicity tests to assess pollutants removal during wastewater treatment and the quality of receiving waters in Argentina
Authors: Gómez Carlos E. , Contento Liliana , Carsen Andrés E.
Published: August 2002

In Argentina, legislation to control adverse impacts of effluent discharges and the quality of receiving waters is scant and relies mainly on the physicochemical characteristics of the effluents and receiving waters. Objectives of this study were to use standardized acute toxicity tests to assess treatment of petrochemical industry effluents and the toxicity of various treated industrial effluents in the Buenos Aires metropolitan area and their receiving waters. Tests for the first objective used Daphnia magna and Ceriodaphnia dubia; those for the second used D. magna, Spirillum volutans, and Scenedesmus spinosus. Chemical analyses demonstrated that the removal of aromatic hydrocarbon compounds (benzene, toluene, ethylbenzene, xylene, styrene, and naphthalene) from the petrochemical effluents ranged between 77 and 93%, but toxicity removal was significantly lower: untreated effluents were very toxic and treated effluents were very toxic to toxic [acute toxicity units (TUa)>3]. Physicochemical parameters measured according to current Argentinian regulations indicated that industrial effluents (e.g., from textile and paper industries) were within established guidelines, but 25% of the samples were moderately to highly toxic (TUa>1.33). However, for the receiving waters, toxicity tests were moderate to very toxic. The results show the need of including tests for toxicity of discharged effluents, and their effects on receiving waters of Argentina, especially for regulatory purposes. © 2001 John Wiley & Sons, Inc. Environ Toxicol 16: 217–224, 2001
Heat shock protein 70 levels in rainbow trout primary epidermal cultures in response to 2,4‐dichloroaniline exposure: A novel in vitro aquatic toxicity marker
Authors: Kilemade Michael , Mothersill Carmel
Published: August 2002

The aim of this work was to investigate the use of the heat shock protein, HSP 70, as a sublethal measurement of ecotoxicity and to identify if the amount of HSP 70 synthesized is proportional to the chemical stress applied. This was achieved by quantifying the HSP 70 levels in primary cultured rainbow trout, Oncorhynchus mykiss (R.), skin epidermal cells in response to 2,4‐dichloroaniline (2,4‐DCA) exposure. The cellular stress response protects organisms from damage resulting from exposure to a wide variety of stressors including xenobiotics. The use of a HSP 70 polyclonal antibody on rainbow trout primary epidermal skin cultures exposed to 2,4‐DCA was investigated as a possible biomarker for environmental stress using an immunocytochemical approach. The epidermis is highly susceptible, as it is the interface between the fish and its aquatic environment. In this study we have developed a simple in vitro system for aquatic‐toxicity risk assessment. A method for the quantification of heat shock (stress) protein levels by immunocytochemistry is described. The antibody dilution range enabled the detection and quantification of only the inducible HSP 70 fraction. A 1:2000 dilution was decided upon. This assay was effective in detecting and quantifying the induced HSP 70. There was a direct toxicant concentration‐dependent increase in the levels of the cellular stress protein in the primary epidermal cultures. Enhanced localization of HSP 70 in the nuclei of the epidermal cells was observed following exposure to 2,4‐DCA. This work indicated the possibility of using heat shock protein induction and subsequent quantification as a sensitive system for aquatic toxicity risk assessment. © 2001 John Wiley & Sons, Inc. Environ Toxicol 16: 253–259, 2001
Making Eco‐Efficiency the Foundation of Environmental Policy Reform
Authors: Rondinelli Dennis A.
Published: August 2002

Environmental policy in the United States should refocus on eco‐efficiency and pollution prevention.
© 2001 John Wiley & Sons, Inc.
Reduced‐trellis equalization using the M‐BCJR algorithm
Authors: Fragouli Christina , Seshadri Nambirajan , Turin William
Published: August 2002

The complexity of channel equalization using the BCJR algorithm [Bahl LR et al. IEEE Transactions on Info. Theory 1974; 20: 284–287] grows exponentially with the channel memory. The M‐BCJR algorithm [Franz V, Anderson J. IEEE J. Selected Areas Comm. 1998; 16(2): 186–195] provides a method for reduced‐trellis channel equalization, but its performance varies significantly with the distribution of a channel energy to its taps. This paper proposes a variation of the M‐algorithm, based on the implementation of the BCJR algorithm in the logarithmic domain, which can offer robust performance. Designer choices such as the decision delay, maximum and minimum phase transformation, and selection of states are discussed. Simulation results demonstrate the effect of different parameters on the proposed algorithm's performance. Copyright © 2001 John Wiley & Sons, Ltd.
Optimization of parameters in electron probe microanalysis
Authors: Bonetto Rita , Castellano Gustavo , Trincavelli Jorge
Published: August 2002

A method for the refinement of atomic and experimental parameters applicable to several spectroscopic techniques is presented. This kind of procedure, previously used in x‐ray diffraction, is shown to be a powerful tool in electron probe microanalysis (EPMA). This method consists of minimizing the differences between an experimental x‐ray spectrum and a function proposed to account for the bremsstrahlung and characteristic peaks from the corresponding sample, and also for detection artifacts. This complicated function involves several parameters related to different sources (x‐ray production, x‐ray attenuation, sample composition, x‐ray detection, etc.). Initial values must be supplied for them, and after a numerical iterative procedure is performed, improved values are achieved. Depending on the particular situation, certain parameters may be known a priori, so that they can be fixed, allowing the others to vary. In this way, the method can be used for different purposes: determination of atomic parameters such as fluorescence yields, transition rates or photoelectric cross‐sections, quantitative standardless analysis, determination of detector characteristics, etc. This work is intended to present the general aspects of the method for refining EPMA parameters, and to give some examples of its application to the aforementioned issues. Even when only EPMA spectra are included in this work, the method can be applied to different spectroscopic techniques, such as x‐ray fluorescence, particle‐induced x‐ray emission, etc. Copyright © 2001 John Wiley & Sons, Ltd.
Meiotic crossing‐over in the regions of homology between homeologous chromosomes V
Authors: Shubochkina Elena A. , Nielsen Trine L. , Nilsson‐Tillgren Torsten
Published: August 2002

Homeologous chromosomes V of Saccharomyces cerevisiae and S. carlsbergensis virtually do not recombine in meiosis. Artificially created short regions of homology were found toinduce meiotic crossing‐over if they contained sequences located upstream of the S. carlsbergensis ILVI gene. Heterozygous restriction site markers were introduced withinthe 1.1 kb region of homology to monitor conversion events associated with the crossovers. In the presence of five heterozygosities, 85% of crossovers showed associated conversion. Crossovers with no detected conversion were found in the two largest (0.34 and 0.29 kb) intervals, into which the 1.1 kb region was divided by the introduction of the five markers, whereas the shortest conversion tracts observed did not exceed 0.26 kb. Several lines of evidence suggest that each crossover required a formation of heteroduplex DNA with the considerable minimal length of ∼200–260 bp. Copyright © 2001 John Wiley & Sons, Ltd.
Increasing sulphite formation in Saccharomyces cerevisiae by overexpression of MET14 and SSU1
Authors: Donalies Ute E. B. , Stahl Ulf
Published: August 2002

Saccharomyces cerevisiae produces sulphite as an intermediate product during the assimilatory reduction of sulphate to sulphide. Three genes, MET3, MET14 and MET16, are essential for this reduction. We investigated the level of transcription of these genes in strains of S. cerevisiae with high, medium and low sulphite formation. The level of MET14‐ and MET16‐mRNA varied with sulphite production, whereas the level of MET3‐mRNA was very weak in almost all strains. We also analysed the effect of overexpression of MET14 and MET16 on sulphite formation. Two strains with low sulphite production were transformed with high‐copy plasmids containing either or both MET14 and MET16. The overexpression of these two genes leads to a two‐ to three‐fold sulphite formation. In addition, inactivation of MET10, encoding a subunit of the sulphite reductase, also leads to a distinct increase in sulphite formation; however, the cells became methionine auxotroph. The overexpression of SSU1, a gene encoding a putative sulphite pump, yields a slight increase in sulphite accumulation, whereas overexpression of SSU1, together with MET14, increases sulphite formation up to 10‐fold. Furthermore, sulphite formation strongly depends on growth conditions, e.g. yeast transformants growing in wort produce much higher amounts of sulphite when compared to growth in minimal media. The addition of glucose can also increase the sulphite formation in strains overexpressing MET14 and/or SSU1 under oxygen‐limiting conditions, while the addition of glucose has no significant effect under aerobic conditions. Copyright © 2002 John Wiley & Sons, Ltd.
Assessment of testicular endocrine function in captive African elephants by measurement of urinary and fecal androgens
Authors: Ganswindt Andre , Heistermann Michael , Borragan Santiago , Hodges J. Keith
Published: August 2002

Androgen measurements in urine and/or feces represent a potentially important tool for monitoring testicular endocrine function in the African elephant. To assess the feasibility of this approach, the aims of the present study were to: 1) examine the presence and relative abundance of immunoreactive testosterone (iT) and its 5α‐reduced 17‐oxometabolite epiandrosterone (iEA) in African elephant excreta, and 2) compare urine and fecal androgen profiles in animals of different ages and during the musth and non‐musth condition. Urine and fecal samples were collected over periods of up to 3 years from five bulls (ages 7–24 years) living in three mixed social groups. In parallel, indications of musth were recorded by keeper staff as an independent marker of male androgen status. Measurements of iT and iEA were carried out by enzymeimmunoassay (EIA) following methanolic extraction of hydrolyzed urine and lyophilized fecal powder. High‐pressure liquid chromatography (HPLC) of musth phase samples confirmed the presence of substantial quantities of testosterone (T) and epiandrosterone (EA) in both urine and feces. EA was predominant in feces, whereas T was more abundant in urine. In each male, the two androgen measures were significantly correlated (feces, r = 0.71–0.93, P < 0.0001; urine, r = 0.86–0.91, P < 0.0001), as were fecal and urinary concentrations of each of the two androgens measured (r = 0.35–0.77, P < 0.0001). Moreover, in the two oldest males that showed clear signs of musth, levels of iEA and iT were markedly elevated during musth compared to non‐musth periods (differences were significant for feces in both animals, but in urine only for one). Collectively, the data show that measurement of urinary and fecal androgens generates useful information on gonadal status in male African elephants, and as such should provide new opportunities to improve the management and welfare of bulls maintained in captivity, as well as to examine physiological correlates of reproductive function in free‐ranging animals. Zoo Biol 21:27–36, 2002. © 2002 Wiley‐Liss, Inc.
Postoperative Biliary Ascariasis: Presentation and Management—Experience
Authors: Wani Nazir A. , Shah Omar J. , Naqash Sameer H.
Published: August 2002

Subsequent to preoperative and perioperative indications the common bile duct was explored in 705 patients over a 12‐year period, from January 1983 to December 1994. Consequent postoperative T‐tube cholangiography revealed the presence of worms in 22 patients. Expulsion of the worms followed T‐tube irrigation with 0.9% normal saline in 18 patients. Only one patient had to be reexplored to remove the ascaris. In two patients the worm was removed along with the T‐tube, and in one patient the worm came out through the T‐tube tract.
Impact of Initial Surgical Treatment on Survival of Patients with Differentiated Thyroid Cancer: Experience of an Endocrine Surgery Center in an Iodine‐deficient Region
Authors: Duren Mete , Yavuz Nihat , Bukey Yusuf , Ozyegin M. Ates , Gundogdu Sadi , Açbay Ozer , Hatemi Husrey , Uslu Ihami , Onsel Çetin , Aksoy Figen , Oz Feriha , Unal Gurcan , Duren Erol
Published: August 2002

This retrospective clinical study was designed to analyze the impact of the initial surgical procedure on the survival of 1000 patients with differentiated thyroid cancer of follicular cell origin who had a thyroid operation and were followed for the 30 years between 1968 and 1998 (median 14 years) in an iodine‐deficient region where goiter is endemic. There were 753 women and 247 men with a mean age of 42.8 ± 6.7 years (range 17–86 years). Patients were divided into three groups. All patients had undergone thyroxine treatment and thyroid‐stimulating hormone (TSH) suppression, and most had had iodine‐131 treatment postoperatively. Group A consisted of 336 patients with differentiated thyroid cancer (DTC) who were treated with bilateral subtotal thyroidectomy in our institution or elsewhere. Group B consisted of 158 patients with DTC who were treated initially with unilateral total lobectomy and contralateral subtotal lobectomy in our institution or elsewhere and underwent reoperation in our department. Group C consisted of 506 patients with DTC who were treated initially with total or near‐total thyroidectomy in our department. Kaplan‐Meyer survival analysis was used. Recurrence was seen in 23% and death in 8% of the patients. The 20‐year survival rates were 76%, 85%, and 92% for groups A, B, and C, respectively. The survival difference among the patients of group A and groups B and C was found to be statistically different (p < 0.001). Long‐term survival of patients with differentiated thyroid cancer living in endemic areas for goiter can be influenced by the initial surgical treatment. Patients treated initially with total or near‐total thyroidectomy appear to have a better prognosis.
Indicators of Fatigue and of Prolonged Weaning from Mechanical Ventilation in Surgical Patients
Authors: O'Keefe Grant E. , Hawkins Kenneth , Boynton Jackie , Burns Darren
Published: August 2002

Indicators of weaning success have been tested primarily in patients who have been ventilated for short periods of time, and they may not be as accurate in cases where support has been required for longer than a few days. In patients requiring longer periods of support it is difficult to estimate the likelihood of successful liberation. Therefore we evaluated established weaning indices for their accuracy in surgical patients who required ≥ 72 hours of mechanical ventilation. Surgical patients who required mechanical ventilation for ≥ 72 hours were prospectively followed (over 6 months). We obtained standard indices of ventilatory function daily once patients were ready to wean. These indices included the respiratory rate/tidal volume ratio (RSBI), the maximal inspiratory pressure, and the minute ventilation. The duration of weaning and explicitly defined episodes of fatigue were the outcomes of interest. Statistical analyses evaluated the multiple factors that might influence the duration of weaning. Ninety‐five patients (66% trauma; 34% surgery) survived to begin weaning, and 93% were liberated. The median duration of mechanical ventilation prior to weaning was 4 days (range 3–16 days), and the median duration of weaning was 3 days (range 0–56 days). Fatigue occurred in 36 patients and was not reliably predicted by any of the weaning measurements. However, a RSBI of >105 on the first day of weaning was associated with prolonged weaning. By multivariate analysis, an RSBI of >105 on the first day of weaning predicted prolonged weaning (hazard ratio 1.9; p= 0.03). After 72 hours of mechanical ventilation, clinical fatigue and successful liberation are not reliably predicted by standard indices of respiratory muscle strength and reserve. However, an RSBI of >105 observed once the patient is ready to wean is associated with prolonged weaning.
Pancreaticobiliary Maljunction‐Associated Pancreatitis: An Experimental Study on the Activation of Pancreatic Phospholipase A2
Authors: Nakamura Tetsuro , Okada Akira , Higaki Jun , Tojo Hiromasa , Okamoto Mitsuhiro
Published: August 2002

Congenital dilatation of the bile duct (CDBD), or choledochal cyst, is often complicated by recurrent pancreatitis. Reflux of pancreatic juice into the bile duct through pancreaticobiliary maljunction (PBM), an anomaly commonly associated with CDBD, and ensuing activation of pancreatic enzymes could be involved in the pathophysiologic mechanism of recurrent pancreatitis. A study was undertaken to follow the time course of the activity of phospholipase A2 (PLA2) in animal models of PBM. The assay procedures for PLA2 were evaluated, as were the conditions for separating the active enzyme from its inactive proenzyme (pro‐PLA2) by immunoblotting. A rat model was designed according to Block's method with some modifications. The kinetics of prophospholipase A2 (proPLA2) activation in bile was examined by measuring PLA2 activity and by immunoblotting using anti‐rat pancreatic enzyme antibody after separating PLA2 from its zymogen under nonreducing conditions. Experimental animals were divided into three groups: group 1 (PBM group) in which bile and pancreatic juice were mixed with occlusion of the papilla; group 2, in which the papilla and hepatic hilus were occluded without mixing the two juices; and group 3, in which simple laparotomy was done. In group 1 animals, pro‐PLA2 in bile was activated to its active form. In group 2 animals, where proPLA2 was predominant, there was only slight elevation of PLA2 activity in bile. In group 1 an immunohistologic study demonstrated localization of PLA2 around necrotic foci in the pancreatic parenchyma. These results suggest the involvement of activated PLA2 in the pathogenesis of choledochal cyst‐associated pancreatitis.