bluuebunny/crossref_metadata_2025 huggingface dataset:
Size heterogeneity of telomeric DNA in mouse meiotic chromosomes
Authors: Viera A. , Parra M.T. , Rufas J.S. , Suja J.A.
Published: April 2003

Heterogeneity for the length of telomeric DNA sequences has been found among different mitotic chromosomes in several mammalian species. However, there are no studies reporting such heterogeneity in meiotic chromosomes. To analyse this heterogeneity we have performed fluorescence in situ hybridization with a telomeric (C3TA2)3 peptide nucleic acid (PNA) probe on spread metaphase chromosomes during both male mouse meiotic divisions. Our results show that independently of the meiotic division, telomeric DNA signals were always surrounded by DAPI-stained chromatin, even at centromeric regions. Moreover, we have found heterogeneity for the size of telomeric DNA signals among different chromosomes, between homologues, and even within a given chromosome. We discuss the functional significance of the location of telomeric DNA in condensed meiotic chromosomes, and then the possible origin for the different polymorphisms found.
Uropathogenic Escherichia coli Toxins Induce Caspase-Independent Apoptosis in Renal Proximal Tubular Cells via ERK Signaling
Authors: Chen Ming , Jahnukainen Timo , Bao Wenjie , Daré Elisabetta , Ceccatelli Sandra , Celsi Gianni
Published: April 2003

Background: Pyelonephritis is a risk factor for renal tubular epithelial cell damage. Recent studies have shown that Escherichia coli and/or its toxins may stimulate apoptotic cell death in renal tubular cells, but the underlying molecular mechanisms remain to be elucidated. Methods: Confluent LLC-PK1 cells were exposed to E. coli toxins from overnight cultures of the uropathogenic O6K13H1 (O6) and the nonpathogenic W3110. The cell death was studied with morphological and biological assay. Results:E. coli soluble toxins from uropathogenic O6:K13:H1(O6) strain were found to induce apoptosis in a dose- and time-dependent manner in LLC-PK1 cells. The expression of FasR and the phosphorylation of ERK1/2 were significantly upregulated by O6 soluble toxins in a time-dependent manner. Cell death was completely inhibited by two specific ERK1/2 inhibitors, but not by a broad caspase inhibitor, zVAD-fmk, implicating a caspase-independent pathway via ERK. Moreover, we found that lysophosphatidic acid could trigger a survival signal through G-proteins and PI3K. Conclusion: We demonstrate that apoptosis induced by uropathogenic E. coli toxins is dependent on ERK1/2. Caspases, although being activated, are not necessary for cell death, and they act after the ERK signaling at which point cells become committed to cell death or can be rescued.
NANOSCALE ENGINEERING OF ALUMINIUM SURFACES
Authors: Caicedo-Martinez C. E. , Thompson G. E. , Koroleva E. V.
Published: April 2003

The development of regular, finely spaced, arrays of metal ridges and troughs, i.e. nanotex tures, by surface treatment of aluminium has been probed by atomic force microscopy (AFM) and transmission electron microscopy (TEM), assisted by radio frequency glow discharge optical emission spectrometry (rf GDOES). AFM reveals the grain orientation dependence of the tex ture and its increased dimensions with increased metal purity. TEM reveals atomic number contrast effects at the centres of metal ridges comprising the boundaries of the cells, thus implicating the composition and structure of the substrate. Enrichment of copper in the alloy immediately beneath the residual alumina film is evident in rf GDOES depth profiles; conversely, iron and silicon, present at similar levels as copper, are not detected. This suggests strongly that crucial impurities, i.e. silicon, are present as fine segregates in the alloy with a grain orientation dependent distribution originating from casting. The distribution of segregates controls the dissolution of the adjacent aluminium matrix in surface pretreatment, thus generating nanotex tures of regular arrangements of metal ridges and troughs with an amorphous alumina film developed over the macroscopic aluminium surface.
DESIGN OF LOW WEIGHT COMPONENTS: A THEORETICAL APPROACH
Authors: Wänstrand O. , Kassman-Rudolphi Å , Hogmark S.
Published: April 2003

The commercially available software package Elastica has been used to calculate the von Mises stresses in steel as well as in titanium nitride (TiN) and nickel coated aluminium subjected to spherical indentation. Uncoated steel of three different yield strengths was used as reference material, and indenters of different radii were utilised. The critical loads for plastic deformation arrived at were then applied to an Al alloy coated with 5 μ m TiN, and any yield was detected. In cases where the TiN coating could not protect the Al alloy from plastic flow, the required thickness of an intermediate nickel layer was calculated. It was found that with sharp indenters, it is possible to obtain the same critical load for onset of plastic deformation for TiN coated aluminium as for uncoated hardened steels. When the radius of the indenter is large, however, this is not possible owing to the limited thickness of the TiN coating. With the introduction of an intermediate load carrying nickel layer between the aluminium base material and the thin TiN coating the critical load for onset of plastic deformation can be increased.
HIGH DENSITY INFRARED PROCESSING OF WC/Ni–11P COMPOSITE COATINGS
Authors: Engleman P. G. , Dahotre N. B. , Blue C. A. , Harper D. C. , Ott R.
Published: April 2003

A new high density infrared based coating process has been developed to produce wear resistant coatings on AISI 4340 steel substrates that are of commercial interest. The process combines infrared heating, with power densities up to 35 MW m -2, with room temperature precursor spray deposition processes to rapidly form wear resistant coatings. Here, the process is demonstrated using a 20 vol.-%WC reinforced coating in a Ni-11 wt-%P binder on a AISI 4340 steel substrate, to produce a smooth, high density, 10 μm thick coating with minimal degradation of the WC reinforcement or base steel and a hardness seven times greater than that of the substrate.
SiO2/SiO2-ZnO Optical Multiliayer Coatings Fabricated by Sol-Gel Method
Authors: Mozaffarinia R. , Ashrafizadeh F. , Golozar M.
Published: April 2003

A sol-gel based coating technology has been developed for making multilayer ceramic coatings. The coatings are SiO2 and SiO2-ZnO composites made by dispersing ZnO powders in a sol-gel solution. SiO2/SiO2-ZnO multilayer stacks were alternately coated on glass soda lime substrates. Investigations of the structure and coating analysis were carried out and the durability of the coatings in different environments was evaluated. Reflected spectrums from surface coatings were prepared and the optical behaviour of the layers was studied. The results indicate that the sol-gel process can be used to produce completely stable ceramic multilayer coatings. Analysis of reflected spectrums also indicated that with an increase in the number of alternate layers of SiO2 and SiO2-ZnO, the percentage of reflected beams in the VIS region reduced considerably.
INVESTIGATION OF WEAR PROCESSES ON WORN TOOLS USING RAMAN MICROSCOPY
Authors: Constable C. P. , Yarwood J. , Robinson G. , Luo Q. , Lewis D. B. , Münz W.-D.
Published: April 2003

In order to address the industry driven interest in wear and associated mechanisms of coated tools during dry high speed machining applications, two commercially available physical vapour deposited (PVD) coatings were studied. These were TiAlN based and had multilayered architectures deposited on to cemented carbide 8 mm ball-nosed two flute end mills. Raman microscopy and SEM-EDX analysis were used to characterise the molecular and elemental species, respectively, present on the worn surfaces of tools after controlled lifetime tests milling into A2 HRC58 die steel. This was performed to gain a better understanding of tribochemical reactions that occur in the highly complex wear environment during milling. Cutting temperatures were estimated as ≥950°C, indicated by oxide phase transformations and corroborated by static oxidation studies. In addition, transfer layers of iron/steel and iron oxide species (FeO, Fe3O4, and Fe2O3), oxidation products of the coating (TiO2 and α-Al2O3), and spectral changes owing to deformation and stress state were observed as a consequence of wear. The high spatial resolution (2 μm), sensitivity to structural/chemical changes, and the non-destructive nature of the technique make Raman microscopy ideal for the study of wear on tools with complex geometry that cannot be readily studied by other techniques without difficult sample preparation.
Enhancing Surface Hardness of Titanium Alloy Ti-6Al-4V by Combined Nitriding and CVD Coating
Authors: Kessler O. , Surm H. , Hoffmann F. , Mayr P.
Published: April 2003

Titanium alloys show a relatively high strength to density ratio and good corrosion resistance. Their main disadvantage in many applications is the low hardness and hence low resistance to abrasive wear. The wear resistance of titanium alloys can be enhanced by nitriding, but the compound layer thickness is limited. The requirement of thicker compound layers could be fulfilled by a combination process. The duplex process of nitriding plus moderate temperature chemical vapour deposition (MTCVD) TiCN coating of titanium alloys appears promising. Either pressure nitriding or gas nitriding can be applied to Ti-6Al-4V. With pressure nitriding, homogeneous compound layers can be produced on complex shaped components; however, the combined process must be carried out discontinuously in two reactors, due to the different process parameters. When using gas nitriding, the combined process can be performed continuously in the CVD equipment. With the combined nitriding +MTCVD coating route, thick compound layers could be produced in relatively short process times. The surface microstructures consist of a nitrogen diffusion layer, an intermediate layer, a compound layer, and a TiCN coating. The Ti-6Al-4V surface was characterised by high hardness and good layer adhesion.
Surface Characteristics and Tribological Properties of Ti-Al Intermetallic Compound Coatings on Ferrous Substrates
Authors: Salehi M. , Tahvilian A. , Karimzadeh F.
Published: April 2003

Titanium aluminide intermetallic compound coatings were produced on carbon tool steel surfaces by a two stage pack titanisation and aluminisation process. The coatings were subsequently diffusion annealed at a range of temperatures and times. The diffusion time and temperature at each stage were optimised in order to control the tribological behaviour of the coatings formed. Metallographic, microhardness, X-ray diffraction, and glow discharge optical spectroscopic techniques were used to identify coating and interface regions, and the results show that coatings were produced with graded compositions and properties. Tribological tests were conducted on a conventional reciprocating wear test machine under dry conditions, and the worn surfaces and wear debris were examined by SEM. The results of wear testing indicate that titanium aluminide coatings improve the wear behaviour of carbon tool steel significantly. Subsequent diffusion annealing of the titanium aluminide coatings significantly enhanced the wear resistance of the steel substrates, with a friction coefficient of less than 0.2 being maintained over many test cycles. These results confirm the feasibility of producing a Ti - Al intermetallic compound layer for use in hostile environments.
Thermal stability of carbon S phase in 316 stainless steel
Authors: Li X. Y. , Thaiwatthana S. , Dong H. , Bell T.
Published: April 2003

A low temperature plasma carburising process has been developed to engineer the surfaces of austenitic stainless steels to achieve combined improvements in wear and corrosion resistance. Previous studies have investigated the chemical, mechanical and structural characteristics of this carburised layer produced on AISI 316 steel at temperatures between 400° C and 600° C. The present paper focuses on the thermal stability of this carbon S phase layer. The investigation included isothermal annealing of the S phase layer as well as microstructure and property characterisation of the specimens. The results show that the S phase is metastable. When thermally annealed at certain temperatures for long enough, the carbon S phase decomposes into chromium carbides. Correspondingly, the hardness and corrosion resistance also varied. A preliminary isothermal transformation diagram has been constructed, which provides a basic guideline for the application of low temperature plasma carburised 316 austenitic stainless steel.
Surface engineering of austenitic stainless steel
Authors: Bell T.
Published: April 2003

The inherent poor tribological behaviour of austenitic stainless steels has been a barrier to their wider application under corrosion wear conditions. Therefore, researchers have long dreamt of developing new technologies to enhance the wear resistance of stainless steel surfaces without loss of their attractive ‘stainless’ characteristics. For example, the discovery of low temperature plasma nitriding in the mid 1980s allowed a new phase with a high hardness and good corrosion resistance to be produced on austenitic stainless steel surfaces. Since then much research and development has aimed to combine improvements in wear, corrosion and fatigue properties. This has been demonstrated by various low temperature surface alloying processes (including plasma, ion beam, gaseous and salt bath methods) and increasing numbers of academic publications, reflecting rapidly expanding niche markets in the food, chemical, nuclear and medical sectors. In this paper, the historical evolution and development of low temperature thermochemical surface alloying processes are overviewed. The research and development of low temperature surface alloying of austenitic stainless steels in an attempt to combine improvements in wear, corrosion and fatigue properties are also assessed. Finally, new directions and key areas for future development are identified and discussed.
Structure and corrosion behaviour of stainless steels after plasma and gas nitriding
Authors: Spies H.-J. , Eckstein C. , Zimdars H.
Published: April 2003

The microstructures and corrosion properties of ferritic and austenitic stainless steels have been investigated after plasma and gas nitriding at 200-450° C. Little difference was observed between the surface layers produced by the two nitriding techniques: that on ferritic X6Cr17 consisted of ferrite plus epsilon-carbide, that on the austenitic X5CrNi18-10 was the expanded austenite S phase. Pitting resistance of X5CrNi18-10 was improved by nitriding at up to 420° C, but deteriorated for higher nitriding temperatures. The presence of epsilon-carbides in the layer on X6Cr17 slightly reduced pitting resistance for nitriding temperatures up to 440° C. Annealing the nitrided specimens degraded corrosion resistance by redistributing the nitrogen in the surface layer and promoting chromium nitride precipitation.
Application OF Ni-P-ZrO2-Al2O3-Al3Zr Electroless Composite Coatings and Their Characteristics
Authors: Sharma S. B. , Agarwala R. C. , Agarwala V. , Ray S.
Published: April 2003

This paper investigates the application of Ni-P-ZrO2-Al2O3-Al3Zr (Ni-P-X) electroless coatings on three different substrate materials: commercial aluminium; low carbon steel and carbon fabric, by in situ co-precipitation of Al2O3 and ZrO2 and by co-deposition with Al3Zr. The Ni-P-X coatings have been studied in terms of composition and tribological behaviour. Application of Ni-P-X coatings on carbon fabric and their effect on UTS has also been explained.
Conditions for Formation of Coherent Aluminide Coatings on γ-Tiai by Pack Cementation Process
Authors: Xiang Z. D. , Rose S. R. , Datta P. K.
Published: April 2003

Thermochemical analyses were undertaken for a series of pack powder mixtures for depositing aluminide coatings on γ-TiAl by the pack cementation process. Particular attention was focused on the effects of halide activators on the deposition characteristics of the pack powder mixtures. The activators investigated included the halide salts NH4F, NH4Cl, AlF3 and AlCl3. Based on the results of the analyses, a series of coating deposition experiments was carried out to identify optimum pack powder mixtures for depositing adherent and coherent aluminide coatings on γ-TiAl. It was observed that aluminide coatings consisting of an outer TiAl3 layer and an inner TiAl2 layer with a coherent structure free from microcracking could be deposited on γ-TiAl via inward diffusion of aluminium at 1000 ° C using pack powder mixtures containing 4 wt-%Al or less and 2 wt-%AlCl3 with Al2O3 as the inert filler. A discussion is presented on the conditions that need to be carefully controlled to ensure the deposition of aluminide coatings on γ-TiAl with a coherent structure free from microcracking by the pack cementation process. The oxidation resistance and the thermal stability of the aluminide coatings deposited were evaluated in air at temperatures up to 850 ° C. The results are discussed in relation to the oxide scale formation process and the high temperature stability of the diffusion triplet of TiAl3/TiAl2/TiAl.
Surface hardening for austenitic stainless steels based on carbon solid solution
Authors: Aoki K. , Kitano K.
Published: April 2003

A novel low temperature carburising approach for austenitic stainless steels, the NV Pionite process, is described. The formation of a metal fluoride layer on the surface before carburising allows carbon to be introduced into the workpiece by gas carburising at 450-500° C. Laboratory trials using 316 have been conducted. A single phase expanded austenite diffusion layer with surface microhardness of 810 HV0.05 and good corrosion properties is produced.
Solutions to improve surface hardness of stainless steels without loss of corrosion resistance
Authors: Poirier L. , Corre Y. , Lebrun J. P.
Published: April 2003

Ion nitriding is an extensively industrialised process enabling steel surfaces to be hardened by nitrogen diffusion, with a resulting increase in wear, seizure and fatigue resistance. Unfortunately, its direct application to stainless steels, while enhancing their mechanical properties, also causes a marked degradation in their corrosion resistance. By adapting the plasma process however, it is possible to reconcile improvement of tribological properties with maintenance of corrosion resistance. This may be obtained by working with base nitrogen and/or base carbon plasmas. The material properties obtained with a nitrogen plasma are discussed, using, as an example, the application of this process to the control rod clusters of pressurised water nuclear reactors (PWR). This nitriding process is then compared with low temperature nitriding and/or carburising thermionically enhanced low pressure plasma processes which have been recently developed. Following this type of treatment it is possible to increase the wear rate resistance of austenitic stainless steels by 60 to 700 times, while fully conserving the corrosion resistance of the untreated alloy.
Recurring chromosomal abnormalities in leukemia in PML-RARA transgenic mice identify cooperating events and genetic pathways to acute promyelocytic leukemia
Authors: Le Beau Michelle M. , Davis Elizabeth M. , Patel Bhumi , Phan Vernon T. , Sohal Jastinder , Kogan Scott C.
Published: April 2003

Acute promyelocytic leukemia (APL) is characterized by the PML-RARA fusion gene. To identify genetic changes that cooperate with PML-RARA, we performed spectral karyotyping analysis of myeloid leukemias from transgenic PML-RARA mice and from mice coexpressing PML-RARA and BCL2, IL3, activated IL3R, or activated FLT3. A cooperating mutation that enhanced survival (BCL2) was not sufficient to complete transformation and was associated with multiple numeric abnormalities, whereas cooperating mutations that deregulated growth and enhanced survival were associated with normal karyotypes (IL3) or simple karyotypic changes (IL3R, FLT3). Recurring abnormalities included trisomy 15 (49%), trisomy 8 (46%), and -X/-Y (54%). The most common secondary abnormality in human APL is +8 or partial trisomy of 8q24, syntenic to mouse 15. These murine leukemias have a defined spectrum of changes that recapitulates, in part, the cytogenetic abnormalities found in human APL. Our results demonstrate that different cooperating events may generate leukemia via different pathways.
Human Granulocyte Colony-Stimulating Factor in Children With High-Risk Acute Lymphoblastic Leukemia: A Children’s Cancer Group Study
Authors: Heath John A. , Steinherz Peter G. , Altman Arnold , Sather Harland , Jhanwar Suresh , Halpern Steven , Pieters Richard , Shah Narayan , Steinherz Laurel , Tannous Raymond , Terry William , Trigg Michael E.
Published: April 2003

Purpose: To investigate the effect of granulocyte colony-stimulating factor (G-CSF) on hematopoietic toxicities, supportive care requirements, time to complete intensive therapy, and event-free survival (EFS) and overall survival (OS) in children with high-risk acute lymphoblastic leukemia (HR-ALL).

Patients and Methods: A total of 287 children with HR-ALL were randomly assigned to intensive chemotherapy regimens (New York I [NY I] or NY II) as part of the Children’s Cancer Group (CCG)-1901 protocol. The induction phases consisted of five drugs (vincristine, prednisone, l-asparaginase, daunorubicin, and cyclophosphamide). Initial consolidation comprised six-agent chemotherapy combined with 18 Gy of total-brain irradiation. Patients were randomly assigned to receive G-CSF (5 μg/kg/day) during either induction or initial consolidation. A crossover study analysis was done on the 259 patients who completed both phases of therapy.

Results: The mean time to neutrophil recovery (≥ 0.5 × 109/L) was reduced with G-CSF (16.7 v 19.1 days, P = .0003); however, patients who received G-CSF did not have significantly reduced episodes of febrile neutropenia (149 v 164, P = .41), positive blood cultures (57 v 61, P = .66), or serious infections (75 v 79, P = .62). Hospitalization (14.0 v 13.9 days, P = .87) and induction therapy completion times (NY I, 30.3 v 31.3 days, P = .11; NY II, 33.4 v 32.3 days, P = .40) were not significantly altered. There were no differences in 6-year EFS (P = .24) or OS (P = .54) between patients receiving or not receiving G-CSF on CCG-1901, NY I and NY II.

Conclusion: Children with high-risk ALL do not appear to benefit from prophylactic G-CSF.
Phase II Trial of Gemcitabine in Refractory or Relapsed Small-Cell Lung Cancer: Eastern Cooperative Oncology Group Trial 1597
Authors: Masters Gregory A. , Declerck Lieven , Blanke Charles , Sandler Alan , DeVore Russell , Miller Kathy , Johnson David
Published: April 2003

Purpose: Gemcitabine has shown a broad range of activity in solid tumors, including previously untreated small-cell lung cancer (SCLC). The objective of this phase II trial was to investigate the activity of gemcitabine in patients with relapsed SCLC.

Patients and Methods: SCLC patients with measurable disease who had experienced treatment failure with one prior chemotherapy regimen were considered eligible. Patients were required to have Eastern Cooperative Oncology Group (ECOG) performance status of 0 to 2 and adequate organ function; signed informed consent was also required. Treatment consisted of gemcitabine 1,000 mg/m2 on days 1, 8, and 15 of a 28-day cycle. Patients were stratified according to their previous response to first-line chemotherapy (primary refractory v primary sensitive disease).

Results: Forty-six patients were enrolled onto this phase II trial (20 refractory and 26 sensitive patients). Forty-two of these patients were assessable for response and survival, and 44 were assessable for toxicity. Median patient age was 60 years, and median ECOG performance status was 1. Principal grade 3/4 hematologic toxicities included neutropenia (27%) and thrombocytopenia (27%). The main grade 3/4 nonhematologic toxicities were pulmonary (9%) and neurologic toxicity (14%). Objective responses occurred in 11.9% of patients overall, including one patient with refractory SCLC (5.6%) and four patients with sensitive SCLC (16.7%). Median survival for the overall group was 7.1 months. Survival was not significantly different for patients with refractory versus sensitive disease.

Conclusion: Gemcitabine has modest activity in previously treated SCLC patients. The favorable toxicity profile warrants further investigation, either in combination chemotherapy regimens or with targeted biologic compounds.
Enrollment of Older Patients in Cancer Treatment Trials in Canada: Why is Age a Barrier?
Authors: Yee Karen W.L. , Pater Joseph L. , Pho Lam , Zee Benny , Siu Lillian L.
Published: April 2003

Purpose: To evaluate the enrollment of older patients (≥ 65 years) in Canadian cancer treatment trials and compare accrual of older patients in Canada and the United States.

Patients and Methods: A retrospective analysis of the number of older patients enrolled in National Cancer Institute of Canada Clinical Trials Group (NCIC CTG) treatment trials between 1993 and 1996 was performed. These rates were compared with the corresponding rates in the general population of patients who were ≥ 65 years old and had cancer, obtained from Statistics Canada, and those published by the Southwest Oncology Group (SWOG) in the United States.

Results: Between 1993 and 1996, 4,174 patients were enrolled onto 69 NCIC CTG trials of 16 tumor types. Older patients accounted for 22% of trial enrollees, compared with 58% of the Canadian population with cancer. This discrepancy existed in all cancer types except for multiple myeloma. The percentages of older patients enrolled were also analyzed by study type: 15% in adjuvant trials, 25% in metastatic trials, 29% in investigational new drug trials, 24% in phase I trials, and 21% in supportive care trials. The overall proportion of older patients enrolled onto Canadian trials (22%) was slightly lower than that in SWOG trials (25%).

Conclusion: Age remains a barrier for accrual onto cancer treatment trials, even when reimbursement is not an issue. Strategies to overcome this barrier, including the implementation of trials specifically tailored to patients aged ≥ 65 years, are prudent in light of our aging population.
Cross-Functional Influence in New Product Development: An Exploratory Study of Marketing and R…D Perspectives
Authors: Atuahene-Gima Kwaku , Evangelista Felicitas
Published: April 2003

Previous research in new product development (NPD) has focused on the participation of marketing and R…D personnel, but little attention has been paid to their influence. This study examined the effects of marketing's and R…D's influence and participation on new product performance and the differential effects of personal, new product, and organizational factors on their influence in the NPD process as seen from each other's perspective. The results suggest that marketing's and R…D's self-reported influence and their influence as reported by the other have a differential impact on new product performance. Unlike R…D's participation as perceived by marketing, marketing's participation as perceived by R…D affects new product performance only when its influence is high. The results also suggest that marketing's and R…D's influence in the NPD process is differentially affected by personal, new product, and organizational factors.
Organizational Architecture and Success in the Information Technology Industry
Authors: Mendelson Haim
Published: April 2003

This paper studies an organizational architecture that I call information-age architecture. I define a measure of organizational IQ and test whether it is related to financial and market success using data from the fast-moving information technology industry. Higher organizational IQ is associated with higher profitability and growth. This relationship is stronger in business environments that are characterized by faster clockspeeds.
Technical Note: Longitudinal Performance Stratification—An Iterative Kolmogorov-Smirnov Approach
Authors: Ruefli Timothy W. , Wiggins Robert R.
Published: April 2003

The stratification of entities into statistically distinct levels of performance over time is a problem encountered in a number of research and management settings. Traditional techniques to address this issue (e.g., cluster analysis) often require, either ex ante or ex post, the exogenous specification of the number of groups to be employed in further analysis—and are not especially suited to dealing with distributions over time. The methodology presented here iteratively applies the Kolmogorov-Smirnov two-sample test to identify the number and membership of statistically significantly different performance strata on a longitudinal basis. Monte Carlo simulations compare the new methodology with traditional clustering techniques. An application that stratifies mutual funds by returns illustrates the technique.
bc — prod: A Specialized Branch-and-Cut System for Lot-Sizing Problems
Authors: Belvaux Gaetan , Wolsey Laurence A.
Published: April 2003

bc — prod is a prototype modelling and optimization system designed and able to tackle a wide variety of the discrete-time lot-sizing problems arising both in practice and in the literature. To use bc — prod, the user needs to formulate his/her problem as a mixed integer program using XPRESS-MP's mp — model, a standard mathematical programming modelling language, taking into account a reserved set of key words for specific lot-sizing objects, such as production variables, storage, and demand data, etc. The problem is then solved by the XPRESS-MP branch-and-bound system including lot-sizing specific preprocessing, cutting planes for different aspects of lot-sizing problems, plus general cutting planes, and a lot-sizing-specific primal heuristic. Results are presented for a wide variety of big bucket and small bucket models with set-up and start-up costs and times.
Accounting Information, Aggregation, and Discriminant Analysis
Authors: Arya Anil , Fellingham John , Schroeder Doug
Published: April 2003

Aggregation is a pervasive theme in accounting. The preparation of financial statements involves extensive aggregation—information regarding several transactions is summarized using a few account balances. In this article, we study linear, double-entry aggregation rules. The level of aggregation (transactions versus account balance information) affects a decision maker's ability to discriminate between two entities. We show that the orientation of the discriminant function relative to the row space and the nullspace (two fundamental subspaces) of the double-entry matrix determines the information loss due to aggregation. In addition, we observe that an interdependency in account balances is introduced by the double-entry process. The cause and effect property (debit and credit) translates into a negative covariance being introduced among account balances; this, in turn, affects the decision maker's optimal use of information. Finally, in discussing benefits to aggregation, we present an example in which adopting a double-entry aggregation rule serves as a commitment device for the owner.
Optimal Parallel Inspection for Finding the First Nonconforming Unit in a Batch—An Information Theoretic Approach
Authors: Herer Yale T. , Raz Tzvi
Published: April 2003

We consider the case of a batch of discrete units produced by a process subject to failures under a known probability distribution function, and apply information theory to the problem of finding the first nonconforming unit in the batch at minimum cost. Two distinct but related aspects of this problem were treated: determining which units should be inspected, and determining how many units should be sent for inspection at the same time. The solution is based on the principles of inspecting the product units that maximize the reduction in the uncertainty regarding the location of the first nonconforming unit, and of minimizing the cost per unit of uncertainty reduced. These principles are formalized by means of a series of theorems leading to an easy-to-implement algorithm for managing parallel inspection. This approach is successfully compared with the optimal solution obtained with dynamic programming and with other heuristics.
An Empirical Analysis of Process Industry Transformation Systems
Authors: Dennis Daina , Meredith Jack
Published: April 2003

Process industries share many characteristics because their transformation systems are designed for nondiscrete materials. Hence, the process industries typically are lumped together in a general group and contrasted from the discrete industries as a whole. The result is a poor understanding of the differences between distinct types of process industries. In this article, 19 different process industry sites are analyzed for the purpose of identifying the key differences between their transformation systems. Using cluster analysis, seven major subtypes of process industries are identified within the sample: (1) process job shop, (2) fast batch, (3) custom blending, (4) stock hybrid, (5) custom hybrid, (6) multistage continuous, and (7) rigid continuous. It is shown how these seven subtypes differ on the composite dimensions of (1) materials diversity, (2) equipment, (3) materials movement, and (4) run time. The research and managerial implications of these results are discussed.
Generic Uniqueness of Equilibrium in Large Crowding Games
Authors: Milchtaich Igal
Published: April 2003

A crowding game is a noncooperative game in which the payoff of each player depends only on the player's action and the size of the set of players choosing that particular action: The larger the set, the smaller the payoff. Finite, n-player crowding games often have multiple equilibria. However, a large crowding game generically has just one equilibrium, and the equilibrium payoffs in such a game are always unique. Moreover, the sets of equilibria of the m-replicas of a finite crowding game generically converge to a singleton as m tends to infinity. This singleton consists of the unique equilibrium of the “limit” large crowding game. This equilibrium generically has the following graph-theoretic property: The bipartite graph, in which each player in the original, finite crowding game is joined with all best-response actions for (copies of ) that player, does not contain cycles.
Separating a Superclass of Comb Inequalities in Planar Graphs
Authors: Letchford Adam N.
Published: April 2003

Many classes of valid and facet-inducing inequalities are known for the family of polytopes associated with the Symmetric Travelling Salesman Problem (STSP), including subtour elimination, 2-matching and comb inequalities. For a given class of inequalities, an exact separation algorithm is a procedure which, given an LP relaxation vector x*, finds one or more inequalities in the class which are violated by x*, or proves that none exist. Such algorithms are at the core of the highly successful branch-and-cut algorithms for the STSP. However, whereas polynomial time exact separation algorithms are known for subtour elimination and 2-matching inequalities, the complexity of comb separation is unknown.

A partial answer to the comb problem is provided in this paper. We define a generalization of comb inequalities and show that the associated separation problem can be solved efficiently when the subgraph induced by the edges with x*e > 0 is planar. The separation algorithm runs in 𝒪(n3) time, where n is the number of vertices in the graph.
A Near-Optimal Solution to a Two-Dimensional Cutting Stock Problem
Authors: Kenyon Claire , Rémila Eric
Published: April 2003

We present an asymptotic fully polynomial approximation scheme for strip-packing, or packing rectangles into a rectangle of fixed width and minimum height, a classical NP-hard cutting-stock problem. The algorithm, based on a new linear-programming relaxation, finds a packing of n rectangles whose total height is within a factor of (1 + ε) of optimal (up to an additive term), and has running time polynomial both in n and in 1/ε.
A Note on the Existence of Optimal Policies in Total Reward Dynamic Programs with Compact Action Sets
Authors: Cavazos-Cadena Rolando , Feinberg Eugene A. , Montes-de-Oca Raúl
Published: April 2003

This work deals with Markov decision processes (MDPs) with expected total rewards, discrete state spaces, and compact action sets. Within this framework, a question on the existence of optimal stationary policies, formulated by Puterman (1994, p. 326), is considered. The paper concerns the possibility of obtaining an affirmative answer when additional assumptions are imposed on the decision model. Three conditions ensuring the existence of average optimal stationary policies in finite-state MDPs are analyzed, and it is shown that only the so-called structural continuity condition is a natural sufficient assumption under which the existence of total-reward optimal stationary policies can be guaranteed. In particular, this existence result holds for unichain MDPs with finite state space, but an example is provided to show that this general conclusion does not have an extension to the denumerable state space case.
Stability of Multiclass Queueing Networks Under Priority Service Disciplines
Authors: Chen Hong , Zhang Hanqin
Published: April 2003

In this paper, we establish a sufficient condition for the stability of a multiclass fluid network and queueing network under priority service disciplines. The sufficient condition is based on the existence of a linear Lyapunov function, and it is stated in terms of the feasibility of a set of linear inequalities that are defined by network parameters. In all the networks we have tested, this sufficient condition actually gives a necessary and sufficient condition for their stability.
Development of a Rapid-Response Supply Chain at Caterpillar
Authors: Rao Uday , Scheller-Wolf Alan , Tayur Sridhar
Published: April 2003

As part of its growth strategy, Caterpillar Inc. is launching a new P2000 product line of “compact” construction equipment and worktools. In anticipation of this, they asked the authors to construct and analyze potential P2000 supply chain configurations. Using decomposition and results from network flow theory, inventory theory, and simulation theory, we were able to provide solutions to this problem for different supply chain scenarios provided by Caterpillar. Novel features of our model include expedited deliveries, partial backlogging of orders, and realized sales that are responsive to service. Caterpillar made their decision regarding the P2000 supply chain based on our recommendations.
The Surplus Inventory Matching Problem in the Process Industry
Authors: Kalagnanam Jayant R. , Dawande Milind W. , Trumbo Mark , Lee Ho Soo
Published: April 2003

We introduce a new problem that arises from operations planning in the process industry. This problem involves matching an order book against surplus inventory before production planning. It can be formulated by generalizing the multiple knapsack problem along three dimensions: (i) adding assignment restrictions on items that can be assigned to a knapsack, (ii) adding a new attribute (called “color” in this paper) to an item and then adding the associated “color” constraints that restrict the number of distinct colors that can be assigned to a knapsack, and (iii) considering multiple objectives for optimization. We formulate the problem, provide a result regarding its complexity, and report on our computational experience with solving a set of real instances based on data from the operations of a large steel plant. We then propose a network-flow—based heuristic that yields solutions within 3% of optimal (or the best known feasible solution). This system has been successfully deployed and is now used daily in the mill operations.
On the Asymptotic Optimality of the SPT Rule for the Flow Shop Average Completion Time Problem
Authors: Xia Cathy H. , Shanthikumar George J. , Glynn Peter W.
Published: April 2003

Consider a flow shop with M machines in series, through which a set of jobs are to be processed. All jobs have the same routing, and they have to be processed in the same order on each of the machines. The objective is to determine such an order of the jobs, often referred to as a permutation schedule, so as to minimize the total completion time of all jobs on the final machine. We show that when the processing times are statistically exchangeable across machines and independent across jobs, the Shortest ProcessingTime first (SPT) scheduling rule, based on the total service requirement of each job on all M machines, is asymptotically optimal as the total number of jobs goes to infinity. This extends a recent result of Kaminsky and Simchi-Levi (1996), in which a crucial assumption is that the processing times on all M machines for all jobs must be i.i.d.. Our work provides an alternative proof using martingales, which can also be carried out directly to show the asymptotic optimality of the weighted SPT rule for the Flow Shop Weighted Completion Time Problem.
Inference-Based Sensitivity Analysis for Mixed Integer/Linear Programming
Authors: Dawande M. W. , Hooker J. N.
Published: April 2003

A new method of sensitivity analysis for mixed integer/linear programming (MILP) is derived from the idea of inference duality. The inference dual of an optimization problem asks how the optimal value can be deduced from the constraints. In MILP, a deduction based on the resolution method oftheorem proving can be obtained from the branch-and-cut tree that solves the primal problem. One can then investigate which perturbations ofthe problem leave this proof intact. On this basis it is shown that, in a minimization problem, any perturbation that satisfies a certain system of linear inequalities will reduce the optimal value no more than a prespecified amount. One can also give an upper bound on the increase in the optimal value that results from a given perturbation. The method is illustrated on two realistic problems.
An Exact Performance Evaluation for the Supplier in a Two-Echelon Inventory System
Authors: Cheung Ki Ling , Hausman Warren H.
Published: April 2003

This paper studies a continuous review two-echelon inventory system with a supplier serving multiple retailers. Each location uses a decentralized (Q, R) policy based on installation stocks. Each retailer may set a unique reorder quantity as a multiple of a basic packaging size Q. The supplier, in turn, adopts a similar batch replenishment policy. Our objective is to derive the exact steady-state performance for the supplier. We show that the inventory position at the supplier can be easily characterized by a uniform distribution. As a result, the closed-form expected cost function is tractable. We also examine the performance of approximation schemes such as the classic Poisson approximation. Our numerical results show that even though the Poisson approximation performs reasonably well in estimating steady-state performance, the cost penalty for using it in optimization may be significant.
Central Limit Theorems for Permuted Regenerative Estimators
Authors: Calvin James M. , Nakayama Marvin K.
Published: April 2003

We prove strong laws of large numbers and central limit theorems for some permuted estimators from regenerative simulations. These limit theorems provide the basis for constructing asymptotically valid confidence intervals for the permuted estimators.
A Lower Bound for the Split Delivery Vehicle Routing Problem
Authors: Belenguer J. M. , Martinez M. C. , Mota E.
Published: April 2003

In this paper we consider the Split Delivery Vehicle Routing Problem (SDVRP), a relaxation of the known Capacitated Vehicle Routing Problem (CVRP) in which the demand of any client can be serviced by more than one vehicle. We define a feasible solution of this problem, and we show that the convex hull of the associated incidence vectors is a polyhedron (PSDVRP), whose dimension depends on whether a vehicle visiting a client must service, or not, at least one unit of the client demand. From a partial and linear description of PSDVRP and a new family of valid inequalities, we develop a lower bound whose quality is exhibited in the computational results provided, which include the optimal resolution of some known instances—one of them with 50 clients. This instance is, as far as we know, the biggest one solved so far.
Information Privacy: Corporate Management and National Regulation
Authors: Milberg Sandra J. , Smith H. Jeff , Burke Sandra J.
Published: April 2003

The 1990s have seen a resurgence of interest in information privacy. Public opinion surveys show that many citizens are becoming greatly concerned about threats to their information privacy, with levels of such concern reaching all-time highs. Perhaps as a response to the growing concerns of citizens, the media are devoting more attention to privacy issues, and governmental regulation of the corporate privacy environment is increasing in many countries. Almost all developed countries have grappled with the trade-offs between open access to information—which enables economic efficiency—and an individual's right to privacy. Consistent with these trade-offs, many recent incidents suggest that regulatory approaches to information privacy, corporate management of personal data, and consumer reactions are becoming tightly interwoven around the world. To provide some insights into these relationships, we develop a conceptual model and test it with a cross-cultural sample from 19 different countries.

In general, we find that a country's regulatory approach to the corporate management of information privacy is affected by its cultural values and by individuals' information privacy concerns. In addition, as governments become more involved in the corporate management of information privacy, internal management of such issues seems to tighten. This result supports previous observations that most firms take a primarily reactive approach to managing privacy by waiting for an external threat before crafting cohesive policies that confront their information practices. Moreover, when corporations are not perceived to adequately manage information privacy issues, and/or when privacy concerns rise, individuals are more inclined to prefer government intervention and be distrustful of firm self-regulation. As such, citizens may look to lawmakers to enact stricter regulation to reduce their privacy concerns. These findings and several international trends suggest that the self-regulatory model of privacy governance may not be sustainable over the long term.

Findings from this research constitute an important contribution to the emerging theoretical base of information privacy research and should be particularly enlightening to those managing information privacy issues. Several directions for future research are also discussed.
Insufficient Bureaucracy: Trust and Commitment in Particularistic Organizations
Authors: Pearce Jone L. , Branyiczki Imre , Bigley Gregory A.
Published: April 2003

Many employees in the world are evaluated and rewarded at work based on who they are (“particularism”) rather than based on impersonal judgments of their performance (“universalis”). Yet the field of organizational behavior has been virtually silent on how employees react to workplaces dominated by particularism. In an effort to understand the role of particularistic organizational practices, several ideas from comparative institutions theories are applied to questions of organizational behavior, and the model is tested in samples of large manufacturing and service organizations in the United States and Hungary. It was found that employees in a modernist political system (United States) did echo social scientists’ claims by reporting that their employers’ personnel practices were comparatively more universalistic than those in organizations operating in a neotraditional polity (Hungary). This perception of differences in personnel practices mediated the relationship between political system and employees’ trust in one another, their perceptions of coworker shirking, and their organizational commitment.