bluuebunny/crossref_metadata_2025 huggingface dataset:
Factors that influence adherence to exercise and their effectiveness: Application to cystic fibrosis
Authors: Prasad S.A. , Cerny F.J.
Published: October 2002

Appropriate, regular exercise is of benefit to patients with cystic fibrosis (CF). As with other segments of the population, it has been difficult to devise exercise programs to which most patients will adhere for long periods of time. In healthy children, factors that are related to positive exercise compliance include social support, perceptions of competency and self‐esteem, enjoyment of activity, and availability of a variety of activities. In patients with CF, complications associated with the disease, e.g., time required for other treatment and fatigue, make compliance with recommended exercise activities more difficult. Factors likely to increase compliance in this population include explicit and continued encouragement and support from the family and healthcare team, and the introduction of behavior‐changing strategies. Pediatr Pulmonol. 2002; 34:66–72. © 2002 Wiley‐Liss, Inc.
Altered apoptotic gene expression and acquired apoptotic resistance in cadmium‐transformed human prostate epithelial cells
Authors: Achanzar William E. , Webber Mukta M. , Waalkes Michael P.
Published: October 2002

BACKGROUND

Cadmium is a suspected prostatic carcinogen, although the underlying mechanisms are unclear. To investigate these mechanisms, we performed molecular comparisons between the cadmium‐transformed prostate epithelial cell line CTPE and the nontumorigenic parental line RWPE‐1.

METHODS

Gene expression patterns were compared by using cDNA arrays, RNase protection assays, and Western blots. Apoptosis was analyzed by using flow cytometry to quantify apoptotic nuclei and an enzyme‐linked immunosorbent assay method to measure DNA fragmentation. Caspase‐3 activity was measured colorimetrically.

RESULTS

Among the genes down‐regulated in CTPE cells were those encoding several members of the caspase family of apoptotic proteases as well as the apoptotic regulator Bax. Ribonuclease protection assays confirmed global down‐regulation of caspase gene expression in CTPE. Decreased Bax expression in CTPE was confirmed by Western blots, which also revealed increased expression of anti‐apoptotic Bcl‐2. Consistent with these changes, CTPE cells exhibited increased resistance to apoptosis induced by cadmium, cisplatin, and etoposide. CTPE cells also exhibited lower caspase‐3 activity vs. RWPE‐1 after etoposide treatment.

CONCLUSIONS

CTPE cells exhibited altered expression of important apoptotic regulators as well as resistance to several apoptotic stimuli. We hypothesize that acquired apoptotic resistance may be a key aspect of cadmium‐induced malignant transformation of prostate epithelial cells and that this may contribute to both tumor initiation and the acquisition of aggressive characteristics subsequent to tumor formation. Prostate 52:236–244, 2002. © 2002 Wiley‐Liss, Inc.
Postatrophic hyperplasia of the prostate in Japan: Histologic and immunohistochemical features and p53 gene mutation analysis
Authors: Tsujimoto Yuichi , Takayama Hitoshi , Nonomura Norio , Okuyama Akihiko , Aozasa Katsuyuki
Published: October 2002

BACKGROUND

Postatrophic hyperplasia (PAH) is one of the patterns of prostatic atrophy but has been regarded as a precursor of prostatic cancer (PCA) because of its possible increase in proliferative activity compared with simple atrophy and morphologic mimicry of PCA.

METHODS

Radical prostatectomy specimens obtained from 28 patients with PCA were analyzed by histologic and immunohistochemical methods by using 34βE12 and Ki‐67 as primary antibodies. Tissue from PAH, PCA, high‐grade prostatic intraepithelial neoplasia (HGPIN), a possible precursor of PCA, and benign hyperplasia were microdissected and p53 gene mutations were examined by the polymerase chain reaction–single strand conformation polymorphism method followed by direct sequencing.

RESULTS

Histologically, PAH consists of compactly arranged small acini with irregular atrophic‐appearing contours, mimicking PCA. PAH lesions were detected in 7 (25%) of 28 cases with PCA: multifocal in 6 of 7 (85.7%) cases, maximum size of lesions ranged from 0.3 to 2.3 mm. Mild nuclear enlargement and small nucleoli were observed in all cases. Capsular or perineural invasion, crystalloids, and mitotic figures were not found in any case. Inflammatory changes and fibrosis near PAH were found in 100% and 71% of cases, respectively. PAH involved non‐transition zone in all cases and occasionally involved transition zone. Forty‐three percent of PAH lesions were in proximity (<2 mm) to PCA. None of the clinical and pathologic factors examined were correlated with the presence of PAH. Immunohistochemical analysis by using 34βE12 revealed intact basal cells. Proliferative activity defined by positive rate for labeling with MIB‐1 antibody was intermediate between benign prostatic hyperplasia and HGPIN. The frequency of p53 mutations in PAH lesions was 5.3%, which was similar to that in HGPIN lesions (4.2%). Benign glands never showed mutations.

CONCLUSION

These findings suggested that PAH might be a precursor for PCA. Prostate 52: 279–287, 2002. © 2002 Wiley‐Liss, Inc.
Performance evaluation of a new algorithm for the detection of remote homologs with sequence comparison
Authors: Kann Maricel G. , Goldstein Richard A.
Published: October 2002

A detailed analysis of the performance of hybrid, a new sequence alignment algorithm developed by Yu and coworkers that combines Smith Waterman local dynamic programming with a local version of the maximum‐likelihood approach, was made to access the applicability of this algorithm to the detection of distant homologs by sequence comparison. We analyzed the statistics of hybrid with a set of nonhomologous protein sequences from the SCOP database and found that the statistics of the scores from hybrid algorithm follows an Extreme Value Distribution with lambda ∼1, as previously shown by Yu et al. for the case of artificially generated sequences. Local dynamic programming was compared to the hybrid algorithm by using two different test data sets of distant homologs from the PFAM and COGs protein sequence databases. The studies were made with several score functions in current use including OPTIMA, a new score function originally developed to detect remote homologs with the Smith Waterman algorithm. We found OPTIMA to be the best score function for both both dynamic programming and the hybrid algorithms. The ability of dynamic programming to discriminate between homologs and nonhomologs in the two sets of distantly related sequences is slightly better than that of hybrid algorithm. The advantage of producing accurate score statistics with only a few simulations may overcome the small differences in performance and make this new algorithm suitable for detection of homologs in conjunction with a wide range of score functions and gap penalties. Proteins 2002;48:367–376. © 2002 Wiley‐Liss, Inc.
Optimization of a new score function for the generation of accurate alignments
Authors: Qian Bin , Goldstein Richard A.
Published: October 2002

The accuracy of the alignments of protein sequences depends on the score matrix and gap penalties used in performing the alignment. Most score functions are designed to find homologs in the various databases rather than to generate accurate alignments between known homologs. We describe the optimization of a score function for the purpose of generating accurate alignments, as evaluated by using a coordinate root‐mean‐square deviation (RMSD)‐based merit function. We show that the resulting score matrix, which we call STROMA, generates more accurate alignments than other commonly used score matrices, and this difference is not due to differences in the gap penalties. In fact, in contrast to most of the other matrices, the alignment accuracies with STROMA are relatively insensitive to the choice of gap penalty parameters. Proteins 2002;48:605–610. © 2002 Wiley‐Liss, Inc.
A novel fold recognition method using composite predicted secondary structures
Authors: An Yuling , Friesner Richard A.
Published: October 2002

In this work, we introduce a new method for fold recognition using composite secondary structures assembled from different secondary structure prediction servers for a given target sequence. An automatic, complete, and robust way of finding all possible combinations of predicted secondary structure segments (SSS) for the target sequence and clustering them into a few flexible clusters, each containing patterns with the same number of SSS, is developed. This program then takes two steps in choosing plausible homologues: (i) a SSS‐based alignment excludes impossible templates whose SSS patterns are very different from any of those of the target; (ii) a residue‐based alignment selects good structural templates based on sequence similarity and secondary structure similarity between the target and only those templates left in the first stage. The secondary structure of each residue in the target is selected from one of the predictions to find the best match with the template. Truncation is applied to a target where different predictions vary. In most cases, a target is also divided into N‐terminal and C‐terminal fragments, each of which is used as a separate subsequence. Our program was tested on the fold recognition targets from CASP3 with known PDB codes and some available targets from CASP4. The results are compared with a structural homologue list for each target produced by the CE program (Shindyalov and Bourne, Protein Eng 1998;11:739–747). The program successfully locates homologues with high Z‐score and low root‐mean‐score deviation within the top 30–50 predictions in the overwhelming majority of cases. Proteins 2002;48:352–366. © 2002 Wiley‐Liss, Inc.
Physicochemical explanation of peptide binding to HLA‐A*0201 major histocompatibility complex: A three‐dimensional quantitative structure‐activity relationship study
Authors: Doytchinova Irini A. , Flower Darren R.
Published: October 2002

A three‐dimensional quantitative structure‐activity relationship method for the prediction of peptide binding affinities to the MHC class I molecule HLA‐A*0201 was developed by applying the CoMSIA technique on a set of 266 peptides. To increase the self consistency of the initial CoMSIA model, the poorly predicted peptides were excluded from the training set in a stepwise manner and then included in the study as a test set. The final model, based on 236 peptides and considering the steric, electrostatic, hydrophobic, hydrogen bond donor, and hydrogen bond acceptor fields, had q2 = 0.683 and r2 = 0.891. The stability of this model was proven by cross‐validations in two and five groups and by a bootstrap analysis of the non‐cross‐validated model. The residuals between the experimental pIC50 (‐logIC50) values and those calculated by “leave‐one‐out” cross‐validation were analyzed. According to the best model, 63.2% of the peptides were predicted with |residuals| ≤ 0.5 log unit; 29.3% with 1.0 ≤ |residuals| < 0.5; and 7.5% with |residuals| > 1.0 log unit. The mean |residual| value was 0.489. The coefficient contour maps identify the physicochemical property requirements at each position in the peptide molecule and suggest amino acid sequences for high‐affinity binding to the HLA‐A*0201 molecule. Proteins 2002;48:505–518. © 2002 Wiley‐Liss, Inc.
Subdomains in the F and G helices of bacteriorhodopsin regulate the conformational transitions of the reprotonation mechanism
Authors: Martinez Lynell C. , Thurmond Robin L. , Jones Philip G. , Turner George J.
Published: October 2002

We have performed cysteine scanning mutagenesis of the bacteriorhodopsin mutant D85N to explore the role of individual amino acids in the conformational transitions of the reprotonation mechanism. We have used whole‐cell reflectance spectroscopy to evaluate the spectral properties of the 59 mutants generated during a scan of the entire F and G helices and the intervening loop region. Cys mutants were grouped into one of six phenotypes based on the spectral changes associated with their M ↔ N ↔ O intermediate‐state transitions. Mutations that produced similar phenotypes were found to cluster in discrete molecular domains and indicate that M, N, and O possess distinct structures and that unique molecular interactions regulate the transitions between them. The distribution of these domains suggests that 1) the extramembranous loop region is involved in the stabilization of the N and M intermediates, 2) lipid‐protein interactions play a key role in the accumulation of N, and 3) the amino acid side‐chain interactions in the extracellular portion of the interface between helices G and A participate in the accumulation of M. Proteins 2002;48:269–282. © 2002 Wiley‐Liss, Inc.
Protein domain identification and improved sequence similarity searching using PSI‐BLAST
Authors: George Richard A. , Heringa Jaap
Published: October 2002

Protein sequences containing more than one structural domain are problematic when used in homology searches where they can either stop an iterative database search prematurely or cause an explosion of a search to common domains. We describe a method, DOMAINATION, that infers domains and their boundaries in a query sequence from local gapped alignments generated using PSI‐BLAST. Through a new technique to recognize domain insertions and permutations, DOMAINATION submits delineated domains as successive database queries in further iterative steps. Assessed over a set of 452 multidomain proteins, the method predicts structural domain boundaries with an overall accuracy of 50% and improves finding distant homologies by 14% compared with PSI‐BLAST. DOMAINATION is available as a web based tool at http://mathbio.nimr.mrc.ac.uk, and the source code is available from the authors upon request. Proteins 2002;48:672–681. © 2002 Wiley‐Liss, Inc.
Numerical simulation of permeation through vacuum‐coated laminate films
Authors: Mueller K. , Weisser H.
Published: October 2002

The material usage in the packaging market of Germany has decreased over the last few years. This trend results from the substitution of heavy packages with light‐weight, flexible materials. In this context, aluminium foil‐based multilayer films have been partly replaced by metallized laminates in food packaging technology. Other coating materials, such as Al2O3 or SiOx, are used where transparent films are desired. The disadvantage of these vacuum‐coated layers is the existence of pinholes which allow diffusion processes, in contrast to aluminium foil‐based multilayer films. In this study the barrier behaviour of vacuum coated laminate films was predicted by numerical simulation. The results are presented in terms of dimensionless parameters so that they may be transferred to analogous problems. This model provides a method to calculate the oxygen permeation through coated laminates. However, it is invalid for condensable gases such as water vapour. The simulation is suited for characterizing the influence of the compound structure on the barrier properties of vacuum coated laminate films. The results are verified by comparing the calculated with measured values. Copyright © 2002 John Wiley & Sons, Ltd.
First‐order versus high‐order stochastic models for computer intrusion detection
Authors: Ye Nong , Ehiabor Timothy , Zhang Yebin
Published: October 2002

This paper presents two different methods of applying stochastic models to computer intrusion detection. One method is based on a first‐order stochastic model, specifically a Markov chain model. The other method is based on a partial high‐order stochastic model. Stochastic models are used to build a profile of normal activities on a computer from the training data of normal activities on the computer. The norm profile is then used to detect anomalous activities from testing data of both normal and intrusive activities on the computer for intrusion detection. Audit data of computer activities contain a sequence of computer events that is represented as a series of event transitions in stochastic models. The comparison of detection performance between the Markov chain model application and the partial high‐order stochastic model application reveals the better detection performance of the Markov chain model application to computer intrusion detection. Copyright © 2002 John Wiley & Sons, Ltd.
Is the Pauli exclusive principle an independent quantum mechanical postulate?
Authors: Kaplan I. G.
Published: October 2002

Foundation of the Pauli exclusive principle is discussed. It is demonstrated that the indistinguishability principle is insensitive to the permutation symmetry of the wave function and cannot be used as a criterion for the verification of the Pauli exclusive principle. The heuristic arguments are given in favor that the existence in nature of only the nondegenerate permutation representations (symmetrical and antisymmetrical) is not occasional. As follows from our analysis of possible scenarios, the permission of degenerate permutation representations leads to contradictions with the concept of particle identity and their independence. Thus, the prohibition of degenerate permutation states by the Pauli exclusive principle follows from the general physical assumptions inside quantum theory, but the problem of spin–statistics connection is still open. It is pointed out that the Pauli exclusive principle and the Jahn–Teller effect have some similar features. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2002
Calculated geometries and charge distributions of 4n and 4n + 2 π‐ring systems linked with −CH: An asymmetric versus symmetric π‐delocalization
Authors: Buck Henk
Published: October 2002

With the assistance of quantum chemical calculations we discussed the geometrical and charge density differences between [4n]CH and [4n + 2]CH cations for [4n] and [4n + 2] π cyclic‐membered rings substituted with a CH group. In the case of [4n] and [4n + 2] membered rings we are dealing with antiaromaticity and aromaticity, respectively, in the ring systems. The calculations were performed with the Hückel molecular orbital (HMO) description including a variable bond‐length–dependent resonance integral. Furthermore, the HMO method was used with (limited) configuration interaction (CI) in combination with a valence bond (VB) formalism. We focused on the symmetry of π delocalization with respect to the different kind of cations. A symmetrical π delocalization was found for the [4n + 2] CH cations and an asymmetrical π delocalization for the [4n]CH cations. Via introduction of top symmetry cations as, for example, in [4n](CH)4n then the degeneracy of the highest‐occupied molecular orbitals (HOMOs) leads to symmetry lowering from D4nh into D2nh accompanied by alternating symmetrically localized π structures. As an example, the [4](CH)4 cation is given. In both cases, as the result of a Jahn–Teller distortion, the original geometry (D2h) and π contribution of the four‐membered ring is maintained. Several cations derived from the [4n] and [4n + 2] membered rings obtained by specific regio substitution of CH groups have been studied. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2002
Spiking structure of amplitude characteristics for ion trajectories in hyperboloidal mass spectrometers: the theory
Authors: Sheretov Ernst P. , Philippov Igor V. , Karnav Tatiana B. , Kolotilin Boris I. , Ivanov Vladimir W.
Published: October 2002

We present a theory that describes a ‘spiking’ structure of the amplitude characteristics for trajectories of ions within a hyperboloidal mass spectrometer (HMS) discovered and reported recently. This effect, as well as modulation parametric resonance, relates directly to a fine structure of the stability diagram for a HMS. A method of extremum characteristic solutions of the Hill equation (developed in our laboratory earlier) has been used in this work. Simple expressions determined the shape of narrow dips (or reversed peaks) in the amplitude of ion oscillation versus stability parameter curves and conditions of their appearance are presented. The results that were calculated from analytical expressions are compared with those obtained from direct computations of ion trajectories in a HMS. This effect with respect to a nature of ‘black holes’ or ‘black canyons’ observed earlier in investigations of trapping efficiency and ion trapping within ion traps is discussed. Copyright © 2002 John Wiley & Sons, Ltd.
The Use of Natural Systems to Remediate Groundwater: Department of Energy Experience at the Savannah River Site
Authors: Blount Gerald C. , Caldwell Cathleen C. , Cardoso‐Neto Joao E. , Conner Karen R. , Jannik G. T. , Murphy Charles E. , Noffsinger David C. , Ross Jeff A.
Published: October 2002

Natural remediation is moving toward the forefront as engineers clean groundwater at the Savannah River Site
(SRS), a major Department of Energy (DOE) installation near Aiken, South Carolina. This
article reviews two successful, innovative remediation methods currently being deployed: biosparging to treat
chlorinated solvents and phytoremediation to address tritium in groundwater. The biosparging system reintroduces
oxygen into the groundwater and injects nutrient compounds for in‐situ remediation. The system has
greatly reduced the concentrations of trichloroethylene (TCE) and vinyl chloride in wells downgradient
from a sanitary landfill (SLF). Phytoremediation is an emerging technology that promises effective and
inexpensive cleanup of certain hazardous wastes. Using natural processes, plants can break down, trap and hold,
or transpire contaminants. This article discusses the use of phytoremediation to reduce the discharge of tritium
to an on‐site stream at SRS. © 2002 Wiley Periodicals Inc.*
OptimalH∞scaling for sensitivity optimization of detection filters
Authors: Edelmayer A. , Bokor J.
Published: October 2002

The paper deals with the sensitivity optimization of detection filters in linear time‐varying (LTV) systems which are subject to multiple simultaneous faults and disturbances. The robust fault detection filter design problem as ascaledH∞filtering problem is considered. The effect of two different input scaling approaches to the optimization process is investigated. The objective is to provide the smallest scaledL2gain of the unknown input of the system that is guaranteed to be less than a prespecified level, i.e., to produce a filter with optimal disturbance suppression capability in such a way that sufficient sensitivity to failure modes should still be maintained. It is shown how to obtain bounds on the scaledL2gain by transforming the standardH∞filtering problem into a convex feasibility problem, specifically, a structured, linear matrix inequality (LMI). Numerical examples demonstrating the effect of the scaled optimization with respect to conventionalH∞filtering is presented. Copyright © 2002 John Wiley & Sons, Ltd.
Dexterous manipulation of an object by means of multi‐DOF robotic fingers with soft tips
Authors: Nguyen Pham Thuc Anh , Arimoto Suguru
Published: October 2002

This article analyzes the dynamics of motion of various setups of two multiple degree‐of‐freedom (DOF) fingers that have soft tips, in fine manipulation of an object, and shows performances of their motions via computer simulation. A mathematical model of these dynamics is described as a system of nonlinear differential equations expressing motion of the overall fingers‐object system together with algebraic constraints due to tight area contacts between the finger‐tips and surfaces of the object. First, problems of (1) dynamic, stable grasping and (2) regulation of the object rotational angle by means of a setup of dual two‐DOF fingers, are treated. Second, the problem of regulating the position of the object mass center by means of a pair of two‐DOF and three‐DOF fingers is considered. Third, a set of dual three‐DOF fingers is treated, in order to let it perform a sophisticated task, which is specified by a periodic pattern of the object posture and a constant internal force. In any case, there exist sensory‐motor coordinations, which are described by analytic feedback connections from sensing to actions at finger joints. In the cases of setpoint control problems, convergences of motion to secure grasping together with the specified object rotational angle and/or the specified object mass center position, are proved theoretically. A constraint stabilization method (CSM) is used for solving numerically the differential algebraic equations to show performances of the proposed sensory‐feedback schemes. © 2002 Wiley Periodicals, Inc.
Super high definition image (WHD: Wide/Double HD) transmission system
Authors: Tanaka Kenji , Suzuki Kenji , Sato Masahito , Arakawa Yoshiki
Published: October 2002

This paper describes a WHD image transmission system constructed from a display projector, CODECs, and a camera system imaging a super high definition image (WHD: Wide/Double HD) corresponding to two screen portions of common high‐vision images. This system was developed as a transmission system to communicate with or transmit information giving a reality‐enhanced feeling to a remote location by using images of super high definition. In addition, the correction processing for the distortions of images occurring due to the structure of the camera system, an outline of the transmission experiments using the proposed system, and subjective evaluation experiments using WHD images are presented. © 2002 Wiley Periodicals, Inc. Syst Comp Jpn, 33(9): 41–49, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.10063
Optimization of requantization parameter for MPEG transcoding
Authors: Kadono Shinya , Etoh Minoru , Yokoya Naokazu
Published: October 2002

This paper considers transcoding in which an MPEG stream is converted to a low‐bit‐rate MPEG stream, and proposes a method in which the transcoding error can be reduced by optimally selecting the quantization parameter for each macroblock. In transcoding with a low compression ratio, it is crucial to prohibit transcoding with a requantization parameter which is 1 to 2 times the quantization parameter of the input stream. Consequently, as the first step, an optimization method for the requantization parameter is proposed which cares for the error propagation effect by interframe prediction. Then, the proposed optimization method is extended so that the method can also be applied to the case of a high compression ratio in which the rate—distortion curve is approximated for each macroblock in the range of requantization parameters larger than 2 times the quantization parameter. It is verified by a simulation experiment that the PSNR is improved by 0.5 to 0.8 dB compared to the case in which a 6 Mbit/s MPEG stream is not optimized by twofold recompression. © 2002 Wiley Periodicals, Inc. Syst Comp Jpn, 33(9): 21–30, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.10096
An intelligent information gathering method for dynamic information mediators
Authors: Kitamura Yasuhiko , Noda Tomoya , Tatsumi Shoji
Published: October 2002

The Internet is spreading into our society rapidly and is becoming one of the information infrastructures that are indispensable for our daily life. In particular, the WWW is widely used for various purposes such as sharing personal information, academic research, business work, and electronic commerce, and the amount of available information is increasing rapidly. We usually utilize information sources on the Internet as individual stand‐alone sources, but if we can integrate them, we can add more value to each of them. Hence, information mediators, which integrate information distributed on the Internet, are drawing attention. In this paper, under the assumption that the information sources to be integrated are updated frequently and asynchronously, we propose an information gathering method that constructs an answer to a query from a user, accessing information sources to be integrated properly within an allowable time period. The proposed method considers the reliability of data in the cache and the quality of answer in order to efficiently access information sources and to provide appropriate answers to the user. As evaluation, we show the effectiveness of the proposed method by using an artificial information integration problem, in which some parameters can be modified, and a real‐world flight information service compared with a conventional FIFO information gathering method. © 2002 Wiley Periodicals, Inc. Syst Comp Jpn, 33(9): 11–20, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.10119
Composition and decomposition learning of reaching movements under altered environments: An examination of the multiplicity of internal models
Authors: Nakano Eri , Flanagan John R. , Imamizu Hiroshi , Osu Rieko , Yoshioka Toshinori , Kawato Mitsuo
Published: October 2002

We have studied the learning processes of reaching movements under novel environments whose kinematic and dynamic properties are altered. In the experiments, we have used, as the kinematic transformation, a rotational transformation which is displayed by rotating a cursor indicating hand position in the orthogonal coordinate system on a CRT; a viscous transformation using viscous field as the dynamic transformation; and a combined transformation of these two transformations. It is observed that the hand trajectory approaches a straight line along with learning and accurately reaches the target. When the combined transformation is learned after the rotational transformation and viscous transformation are learned first, respectively, the final error becomes smaller and the path length also becomes shorter than the case when the combined transformation is learned first. Moreover, the final error and path length of the movement under rotational transformation and viscous transformation when the combined transformation is learned first also become smaller than the case when the rotational and viscous transformations are learned first. These results suggest that the central nervous system has learned separately the multiple internal models which compensate the respective transformations, and has composed or decomposed the respective internal models in accordance with the environmental changes. It may be considered that such multiplicity of internal models makes it possible for the living body to flexibly cope with the environments or tools having various dynamic and kinematic properties. © 2002 Wiley Periodicals, Inc. Syst Comp Jpn, 33(11): 80–94, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.1166
Prediction of the long‐term survival in breast cancer patients according to the present oncological status
Authors: Hatteville Laurence , Mahe Cédric , Hill Catherine
Published: October 2002

After a breast cancer diagnosis, single or multiple events can occur during follow‐up (recurrence, metastasis, and death). An analysis of long‐term survival should take into account not only the initial characteristics of the patient, but also her oncological status (that is, her history) after surgery. For this purpose, we used a technique proposed by Klein, Keiding and Copelan (1994), to predict the probability of a patient being alive 20 years after surgery for a breast cancer, based on data concerning her oncological status at time t. The first step of the model was to estimate the hazard function for each event of interest (recurrence, metastasis, and death) in a Cox model including initial patient characteristics (age, tumour size, number of involved axillary lymph nodes and the Scarff, Bloom and Richardson (SBR) histo‐prognostic grade) and time‐dependent covariates representing the occurrence of intermediate events (recurrence and metastasis). The second step was to use these estimations to calculate the conditional probability of being alive 20‐tyears later for a patient, given her oncological status at timet(t<10 years). In this second step, the method presented by Klein, Keiding and Copelan was extended to include non‐proportional hazards. This model has been applied to a population of 3180 patients operated on for a breast cancer at the Institut Gustave Roussy between 1 January 1954 and 31 December 1983. At the time of surgery, the probability of survival at 20 years is 0.78 for all patients. Ten years after surgery, if no recurrence or metastasis are observed, the probability of survival at 20 years will rise to 0.89. If only a recurrence is observed, the probability of a patient being alive at 20 years will drop to 0.72. If a metastasis and no recurrence is observed, the probability of survival at 20 years will be only 0.18. If both recurrence and metastasis are observed the probability of survival at 20 years will be equal to 0.09. In conclusion, the model used dynamically appraises the prognosis and represents a new approach for studying the outcome of breast cancer patients having undergone surgery. Copyright © 2002 John Wiley & Sons, Ltd.
Periodograms and pulse detection methods for pulsatile hormone data
Authors: Grambsch Patricia , Meller William H. , Victor Grambsch P.
Published: October 2002

Pulse detection algorithms and spectral analysis are the two most common methods for analysing pulsatile hormone data. We compared a popular high quality pulse detection algorithm (CLUSTER) to spectral analysis on a data set comparing luteinizing hormone data in depressed and control women. For these data, periodogram analysis methods, in particular Fisher's periodicity test, were superior in distinguishing the groups. Extending the pulse detection method to include measures of intra‐individual variability improved its discriminatory performance. The two methods complement each other. Copyright © 2002 John Wiley & Sons, Ltd.
Using inverse weighting and predictive inference to estimate the effects of time‐varying treatments on the discrete‐time hazard
Authors: Dawson Ree , Lavori Philip W.
Published: October 2002

We estimate the effects of non‐randomized time‐varying treatments on the discrete‐time hazard, using inverse weighting. We consider the special monotone pattern of treatment that develops over time as subjects permanently discontinue an initial treatment, and assume that treatment selection is sequentially ignorable. We use a propensity score in the hazard model to reduce the potential for finite‐sample bias due to inverse weighting. When the number of subjects who discontinue treatment at any given time is small, we impose scientific restrictions on the potentially observable discontinuation hazards to improve efficiency. We use predictive inference to account for the correlation of the potential hazards, when comparing outcomes under different durations of initial treatment. Copyright © 2002 John Wiley & Sons, Ltd.
Permutation tests for detecting and estimating mixtures in task performance within groups
Authors: Lo Yungtai , Matthysse Steven , Rubin Donald B. , Holzman Philip S.
Published: October 2002

We propose a two‐sample permutation test incorporating mixture models as a general tool for detecting and quantifying effects on task performance. We illustrate the proposed method with examples where the dependent measures under investigation are recorded for normal controls and relatives of patients with schizophrenia on a delayed response, spatial and object working memory task. Our mixture modelling in relatives allows the component distributions to arise from different continuous parametric families. We also investigate the effects of the within‐family correlation and the prior distribution of the mixing proportion on the test results. The power of the test depends on sample sizes, the mixing proportion, the difference in component means and the ratio of component variances. Copyright © 2002 John Wiley & Sons, Ltd.
On the issue of ‘multiple’ first failures in competing risks analysis
Authors: Tai Bee‐Choo , R White Ian , Gebski Val , Machin David
Published: October 2002

In the classical competing risks framework, a subject may only fail from one of several distinct causes. However, in the context of cancer clinical trials where information on first relapse is usually of interest, there could be occasions when ‘multiple’ first recurrences are identified at a particular follow‐up. In this instance, the competing risks methodology cannot be implemented without first tackling the issue of ‘tied’ first failure. When the tied events were substantial, Arriagadaet al. regarded each competing failure separately, and combined the ‘simultaneous’ failures into a single category for analysis. This paper describes two other methods of accounting for ‘multiple’ failures. First, the ties were dealt with by applying a weighting factor which was equal to the reciprocal of the number of ties. We also considered ‘jittering’ which randomly adds or subtracts a small number to each ‘tied’ event time to randomly break the tie. As illustrated using the data obtained from a randomized trial of patients with operable osteosarcoma, the estimates based on Arriagada's approach have larger standard errors. Estimates from the other alternative methods were similar. Multiple jittering has the advantage of wide applicability in any situation of tied survival times. However, it takes a longer computer running time, especially when the number of replicates is large. The weighted Cox approach is the method of choice where statistical software allows its implementation without extra programming effort. Copyright © 2002 John Wiley & Sons, Ltd.
Do make or buy decisions matter? The influence of organizational governance on technological performance
Authors: Leiblein Michael J. , Reuer Jeffrey J. , Dalsace Frédéric
Published: October 2002

This paper investigates how firms' decisions to outsource or internalize production affect their technological performance. While several popular arguments and some anecdotal evidence suggest a direct association between outsourcing and technological performance, the effects of firms' governance decisions are likely to be contingent upon several specific attributes underlying a given exchange. This paper first demonstrates how standard performance models can improperly suggest a positive relationship between firms' outsourcing decisions and their technological performance. Models that account for firm‐ and transaction‐specific features are then presented, which indicate that neither outsourcing nor internalization per se result in superior performance; rather, a firm's technological performance is contingent upon the alignment between firms' governance decisions and the degree of contractual hazards. Copyright © 2002 John Wiley & Sons, Ltd.
A page‐shift transformation format of ISO 10646
Authors: Wu Pei‐Chi
Published: October 2002

ISO 10646 Universal Character Set (UCS) or Unicode covers symbols in most of the World's written languages. There are various UCS transformation formats (UTF). UTF‐8 is compatible with systems that assume 8‐bit characters. One of the problems with UTF‐8 is its space efficiency. For files containing most Asian characters such as Han ideographs, the file sizes increase by about 50% by using UTF‐8. Although the Standard Compression Scheme for Unicode (SCSU) can compress Unicode strings to the size of a locale‐specific character set, it is complicated and is not intended to serve as a general purpose interchange format. This paper proposes a page‐shift transformation format of ISO 10646, called UTF‐S. There are four pages: 1‐byte, 2‐byte, 3‐byte and 4‐byte. Shift to page 0 uses a special code $00_{16}$; shift to page 1, 2, and 3 uses ISO 2022 shift codes SO, SS2, and SS3, respectively. We test several text files and compare these UTF with Big5, a locale‐specific character set. The result shows that the space efficiency of UTF‐S is better than that of UTF‐16 and UTF‐8 and is close to that of SCSU. UTF‐S is suitable for replacing locale‐specific character sets with ISO 10646 in Internet applications, such as the World Wide Web. Copyright © 2001 John Wiley & Sons, Ltd.
An object‐oriented interface for the dynamic memory management of sparse discrete mathematical operators in numerical scientific applications
Authors: Manzini G. , Mazet S.
Published: October 2002

This paper describes an object‐oriented interface for the memory management of sparse discrete mathematical operators in numerical scientific applications. The basic data structure we propose is intended to implement and cope with mathematical vectors in sparse format. This structure allows an effective implementation of more complex data structures, such as matrix and matrix‐like objects, to represent the discrete version of differential operators in numerical application codes. A research example concerning adaptive wavelet algorithms illustrates the possible applications.Copyright © 2002 John Wiley & Sons, Ltd.
Self‐renewal and personal development in professional life
Authors: Reisser Linda
Published: October 2002

The author discusses how senior student affairs administrators juggle busy lives and shares their recipes for maintaining healthy and balanced lifestyles.
A microscale test to measure petroleum oil toxicity to mummichog embryos
Authors: Couillard C. M.
Published: October 2002

A test was developed to compare the toxicity of different petroleum oils to mummichog (Fundulus heteroclitus) embryos. Fertilized eggs were incubated for 11 days at 22.5°C directly on the surface of oil‐contaminated sand without a superficial water layer. The mortality rates, the stage of development, and the prevalence of malformations were determined. No effect was found in controls incubated on sand with water and mineral oil as compared with controls on sand with water alone. Two weathered oils, an Alaska North Slope crude oil (ANCO) and a Mesa light crude oil (MLCO), produced similar symptoms of toxicity: retarded growth and development, pericardial edema, hemostasis, hemorrhages, and spinal deformities. These symptoms are consistent with those observed in other fish species exposed to petroleum oils, suggesting that the results of the bioassay would be applicable to other species. MLCO was more embryotoxic than ANCO. The minimal oil concentrations causing a significant reduction in body length were 4.5 μg oil/g sand for MLCO and 12.7 μg oil/g for ANCO, indicating the assay is sensitive. The slopes and the intercepts of the relationships between concentration and growth did not differ in three dose–response experiments conducted with each oil, indicating that the assay is reliable. Finally, the bioassay is less costly than other available options to assess the toxicity of petroleum oils to marine fish embryos. Further work to improve the standardization of the assay will involve comparison of the toxicity of petroleum oils with reference toxicants and selection of a standard substrate. © 2002 Wiley Periodicals, Inc. Environ Toxicol 17: 195–202, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/tox.10049
Assessment of mutagenicity and toxicity of different‐size fractions of air particulates from La Plata, Argentina, and Leipzig, Germany
Authors: Massolo L. , Müller A. , Tueros M. , Rehwagen M. , Franck U. , Ronco A. , Herbarth O.
Published: October 2002

Airborne particulates, especially fine particles and bound chemical compounds, are a potential mediator of adverse health effects. In this study an analysis was done of the concentration and size distribution of air particulate matter, the content of bound polycyclic aromatic hydrocarbons (PAHs), and the biological effects of organic extracts from different fractions of dust that had been influenced by urban and industrial emissions from the regions of La Plata, Argentina, and Leipzig, Germany, along with samples from control areas. Air particulate matter was sampled in summer and winter in each region using a high‐volume sampler with a six‐stage cascade impactor, classifying dust in six size fractions from 10‐μm particles to those less than 0.49 μm in size. Organic extracts of dust were tested for mutagenicity (Ames test, Salmonella typhimurium TA98 strain, S9+) and cytotoxicity (Tetrahymena pyriformis test system, growth rate, cell respiration). The content of PAHs was analyzed by high‐performance liquid chromatography (HPLC) with diode array and fluorescence detection. Mutagenic and cytotoxic effects were found to be associated with very fine (<0.49 μm) and fine (<1.5 μm) particle‐bound compounds, corresponding to a higher content of PAHs. The mutagenic potency (revertants/m3) associated with particles less than 0.49 μm from urban areas of La Plata was about 1 order of magnitude higher than in particles in the range of 3.0 to 0.49 μm. Fine fractions from sites with an industrial burden were also found to exhibit high mutagenic potency. A similar tendency was observed in cytotoxicity tests with T. pyriformis. This cell system proved to be very sensitive to toxicants in tested dust fractions. The observed biological effects were found to be correlated significantly with concentrations of total PAH, carcinogenic PAHs, and benzo[a]pyrene. © 2002 Wiley Periodicals, Inc. Environ Toxicol 17: 219–231, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/tox.10054
Production of drinking water from raw water containing cyanobacteria—pilot plant studies for assessing the risk of microcystin breakthrough
Authors: Schmidt Wido , Willmitzer Hartmut , Bornmann Katrin , Pietsch Jörg
Published: October 2002

Toxins in cyanobacteria are a recognized risk in the treatment of drinking‐water treatment. Cyanotoxins can occur in two modifications: cell bound and dissolved in water. The process of toxin release may occur naturally, but it also may be induced through the processes of drinking‐water treatment. Both causes of release are relevant to the safety of drinking water. This study investigated cyanotoxin release and elimination through different treatment trains in systematic pilot‐scale studies with water from the Weida Reservoir, in Thuringia, Germany. The Weida Reservoir is a dimictic mesoeutrophic reservoir typical for a number of mountainous areas in Europe, with Planktothrix rubescens as the dominant phytoplankton species, and shows a characteristic seasonal pattern of population development and microcystin occurrence. To assess the risk of microcystin breakthrough, the pilot‐scale results as well as results of laboratory‐scale experiments were used for developing a kinetic model of toxin release in relation to elimination. By calculating removal efficiency of total microcystins (cell bound and dissolved) for different treatment trains, raw water quality was related to the quality targets for finished water, and breakthrough risks could be calculated for given treatment trains and varying cyanobacterial population densities in the reservoir. © 2002 Wiley Periodicals, Inc. Environ Toxicol 17: 375–385, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/tox.10067
Outage probability of cellular mobile radio systems with selective co‐channel interference cancellation receiver in overloaded array environments
Authors: Annamalai A. , Srivastava V.
Published: October 2002

This article outlines a general numerical procedure for computing the probability of outage of a cellular mobile radio system that is equipped with a smart antenna to suppress a few strongest co‐channel interferers (CCI) out of a total ofNIactive interferers by adaptive null‐steering. Aside from the interference‐limited case, refined outage criterion that either treat receiver noise as CCI or consider a minimum detectable receiver signal threshold are studied. Exact closed‐form expressions for both the basic and refined outage criterion are also derived by assuming that all the CCI signals are subject to Nakagami‐mfading with a positive integer fading severity index. Selected numerical examples are provided to illustrate the application of the theory which includes the investigation into the effects of fade distribution of the CCI signals and traffic loading on the outage probability, and also the study of spectrum utilization efficiency improvement using a selective co‐channel interference nulling (cancellation) technique. Copyright © 2002 John Wiley & Sons, Ltd.