bluuebunny/crossref_metadata_2025_split huggingface dataset:
Shift scheduling in services when employees have limited availability: An L.P. approach
Authors: Thompson Gary M. 
Published: October 2002

AbstractThis paper compares two linear programming (LP) models for shift scheduling in services where homogeneously‐skilled employees are available at limited times. Although both models are based on set covering approaches, one explicitly matches employees to shifts, while the other imposes this matching implicitly. Each model is used in three forms—one with complete, another with very limited meal break placement flexibility, and a third without meal breaks—to provide initial schedules to a completion/ improvement heuristic. The term completion/improvement heuristic is used to describe a construction/ improvement heuristic operating on a starting schedule.On 80 test problems varying widely in scheduling flexibility, employee staffing requirements, and employee availability characteristics, all six LP‐based procedures generated lower cost schedules than a comparison from‐scratch construction/improvement heuristic. This heuristic, which perpetually maintains an explicit matching of employees to shifts, consists of three phases which add, drop, and modify shifts.In terms of schedule cost, schedule generation time, and model size, the procedures based on the implicit model performed better, as a group, than those based on the explicit model. The LP model with complete break placement flexibility and implicitly matching employees to shifts generated schedules costing 6.7% less than those developed by the from‐scratch heuristic.
Assembly line design with incompatible task assignments
Authors: Rachamadugu Ram 
Published: October 2002

AbstractAssembly lines are widely used for the mass production of consumer goods and components in large volume production systems. Design of these lines warrants taking into consideration not only cycle time and precedence constraints, but also other restrictions. An important recurring restriction is that some pairs of tasks cannot be assigned to the same station due to factors such as safety, physical demands placed on workers, quality, and technological considerations. We investigate this problem and a current industry practice used for solving this problem. Our investigation of this problem yields three findings. First, we identify a new class of heuristic procedures which dynamically updates task priorities. Our investigations show that this class of heuristics yields better results. Second, extremely greedy procedures such as knapsack heuristics (Hoffmann procedure) continue to perform better than competing heuristics for industrial grade problems even when additional restrictions on task assignments are present. However, when task restrictions are severe, this is no longer true. Lastly, we present an enumerative procedure to search for optimal solutions in the presence of restrictions. Our study shows that while most simple assembly line balancing problems can be solved optimally, presence of additional restrictions such as task assignments makes them inherently more difficult. We provide insights into this aspect.
Management of technology in service firms
Authors: Haynes Ray M. , Thies Emil A. 
Published: October 2002

AbstractThe service sector is receiving increasing attention with respect to technology implementation and productivity issues. At the same time, industry management remains concerned that the integrated nature of real world business is not adequately covered by academicians and their theories. This paper addresses these issues in a unique manner by examining the results of an industry gathered survey in light of three proven service models.Specifically, data collected by a major financial services provider during a customer survey associated with two automated delivery systems, automated teller machines and self‐service gas pumps, was made available. Next, three theoretical models were selected reflecting the integrated nature of the service delivery process. Functional disciplines included operations, marketing and human behavior. The actual management of technology issue was considered from the perspectives of productivity, effectiveness, efficiency and quality factors identified in these models.The customer acceptance and utilization of automated teller machines has been substantially less than the success of self‐service gas during the 1970–1990 period. Comparing the issues of technology management during the implementation of each offers valuable insight into factors requiring consideration when designing automated service delivery systems. Management implications are identified within the framework of lessons learned from studying these two specific technology applications.The contrast in the success of the implementation of technology in the two service sectors studied was linked to three key factors. First, the process must be well defined and measurable characteristics identified prior to changing the system. Second, the goals of the marketing and operations functions must be coordinated with respect to implementation strategy and established capabilities of the system to change. Finally, the technology implementation must consider the needs of the customer and potential tangible benefits, so that customers will utilize the new system at volume levels that justify the initial expense of the technology.
Conducting case study research in operations management
Authors: McCutcheon David M. , Meredith Jack R. 
Published: October 2002

AbstractRecently, there have been numerous calls for more empirical field‐based research to be conducted in operations management (OM). Knowledge of how operations systems work can be enhanced significantly through contact with the “real‐world” conditions that OM models seek to describe. Case study research is a primary means of exploring field conditions but is an unfamiliar methodology for many in OM. Moreover, the case study method is viewed with scepticism by those who consider it to be a weak form of research, one that lacks rigor and objectivity.Here, we offer an introduction to the case study method for OM researchers who may have little background in field based research. We provide an outline of the procedure and cite some excellent sources that cover case study design, data analysis and the philosophical rationale for the methodology. We also identify some recent examples of OM case studies that illustrate our points. We then contrast the various uses for case study research and their different design and theory requirements. An appendix provides a listing of case studies that have appeared in some OM journals in recent years, classifying the studies by their research purpose.However, regardless of their purposes, case study research need to be conducted in a manner that assures maximum measurement reliability and theory validity. We describe some of the steps that must be taken to ensure that a study is as rigorous as possible. We also argue that, properly conducted, a case study is a truly scientific research approach. We conclude by pointing out some areas of OM research where case studies might be particularly valuable.
An evaluation of labor assignment rules when workers are not perfectly interchangeable
Authors: Bobrowski Paul M. , Park Paul Sungchil 
Published: October 2002

AbstractThe dual resource constrained job shop research has considered the issue of labor flexibility. However, labor flexibility has been defined as the ability of the worker to transfer from work center to work center. A more encompassing definition used in this research is that labor flexibility is worker efficiency at each work station. With workers not equally capable at every center, assignments of different workers to the same work center results in different capacity requirements for the same job. The research here examines how to assign labor to work centers when these differences exist. The traditional labor assignment rules, when to move and where to move, are tested against rules that are created to incorporate worker efficiency information. These rules are first evaluated and then subsequently tested on differing matrices representing other labor efficiencies and with alternative dispatching rules. Results of this research indicate a departure from previous results in the dual resource constrained job shop. The research shows that selection of the rule that governs where the worker should move is the most important choice.
Mixing static and dynamic flowtime estimates for due‐date assignment
Authors: Vig Michelle M. , Dooley Kevin J. 
Published: October 2002

AbstractPrediction of job flowtimes is important from the perspectives of both providing internal control and customer satisfaction. More specifically, accurate and precise flowtime prediction can facilitate proper timing for the release of materials and resources, improved accuracy of delivery dates to customers, and identification of jobs that require expediting. The objective of this paper is to introduce a new approach to flowtime prediction which improves performance quality over that found in existing dynamic flowtime estimation models. This new approach, mixed flowtime estimation, incorporates both static and dynamic flowtime estimates into a single, flowtime prediction model. In this investigation, mixed and dynamic models are compared experimentally using computer simulation of a job shop under various congestion conditions and dispatching heuristics. The results of this investigation reveal that the mixed flowtime prediction models provide significant improvements in job shop due‐date estimation performance. Statistically significant performance improvements are obtained in both the average lateness and fraction tardy jobs for mixed estimates. Specifically, average lateness is reduced by 25% in the balanced shop and 40% in the bottleneck shop. This improvement enables a corresponding increase in the accuracy of job flowtime estimates, and, hence, due‐date assignment accuracy. Due‐date performance improvements are observed for each scheduling heuristic investigated.
Calpain and myogenesis: development of a convenient cell culture model
Authors: Dedieu Stéphane , Dourdin Nathalie , Dargelos Elise , Poussard Sylvie , Veschambre Philippe , Cottin Patrick , Brustis Jean‐Jacques 
Published: October 2002

AbstractPrevious studies have led us to hypothesize that m‐calpain plays a pivotal role in myoblast fusion through its involvement in cell membrane and cytoskeleton component reorganization. To support this hypothesis, a convenient and simple myoblast culture model using frozen embryonic myoblasts was developed, which resolved a number of problems inherent to cell primary culture. Biological assays on cultured myoblasts using different media to define the characteristics of the fusion process were first conducted. Proteinase was detectable before the initiation of the fusion process and was closely correlated to the phenomenon of fusion under each culture condition studied. In addition, the study of calpastatin showed that the initiation of fusion does not require a decrease in the level of this endogenous inhibitor of calpains and also confirmed that calpastatin may be implicated in the determination of the end of fusion. On the other hand, analysis of the evolution of myogenic factors revealed that myogenins, MyoD and Myf5, increase very significantly during the formation of multinucleated myotubes. Moreover, the antisense technique against myogenin is capable of preventing the process of fusion by 50%, confirming the pivotal role of this factor in the early stages of differentiation. The possible role of myogenic regulator factors on m‐calpain gene expression is discussed.
Demand chain management theory: constraints and development from global aerospace supply webs
Authors: Williams Tim , Maull Roger , Ellis Bruce 
Published: October 2002

AbstractThis paper develops an empirical and theoretical approach to where strategic capabilities should lie within global aerospace supply chains. Theory from transaction cost economics (TCE) and the resource‐based view (RBV) of the firm are applied to the aerospace sector and used to underpin a theory of demand chain management (DCM). A two‐stage research process was used to generate and validate data from aerospace supply chain case studies. Demand chain driver and resource‐based response categories were identified from these data and are presented. Concluding comments concern current limits of a demand chain theory and implications for practitioners.
Interstitial Po2 Determination by Phosphorescence Quenching Microscopy
Authors: SMITH LANE M. , GOLUB ALEKSANDER S. , PITTMAN ROLAND N. 
Published: October 2002

ABSTRACTObjective: This study introduces the technique of microinjection of phosphor probe into skeletal muscle tissue to determine oxygen tension (Po2) in the interstitium by phosphorescence quenching microscopy.Method: The spinotrapezius muscle of Wistar‐Kyoto rats weighing 240–280 g was surgically isolated and underwent the microinjection procedure. We measured the spatial distribution of phosphor probe 10, 30, and 80 minutes after injection; the tissue Po2 at sites adjacent to arteriolar and venular microvessels; and the decline in tissue Po2 during a 3‐minute period of 8‐Hz contraction.Results: The phosphorescence signal from the probe was undetectable outside a 2.5‐mm radius from the site of injection at the 10‐minute time point, increased to measurable values after 30 minutes, and was double the 30‐minute intensity value after 80 minutes. When used to measure periarteriolar Po2, the tissue microinjection technique demonstrated a nonlinear fall in tissue Po2 with distance away from secondary arterioles (30–40 µm diameter). Conversely, perivenular tissue Po2 increased in a nonlinear manner with distance away from secondary venules (60–70 µm diameter). The tissue Po2 at distances of 16 µm and greater from both types of secondary microvessels was significantly different from values taken directly over the centerline of these microvessels. During muscle contraction, the Po2 fell from a mean precontraction value of 28.3 ± 4.9 mmHg to 8.2 ± 0.9 mmHg at the end of the contraction period.Conclusions: These observations indicate that the microinjection technique yields values for tissue Po2 that are in good agreement with previously published results using oxygen microelectrodes.
The Abscisic Acid-Responsive Kinase PKABA1 Interacts with a Seed-Specific Abscisic Acid Response Element-Binding Factor, TaABF, and Phosphorylates TaABF Peptide Sequences
Authors: Johnson Russell R. , Wagner Ryan L. , Verhey Steven D. , Walker-Simmons Mary K. 
Published: October 2002

AbstractThe abscisic acid (ABA)-induced protein kinase PKABA1 is present in dormant seeds and is a component of the signal transduction pathway leading to ABA-suppressed gene expression in cereal grains. We have identified a member of the ABA response element-binding factor (ABF) family of basic leucine zipper transcription factors from wheat (Triticum aestivum) that is specifically bound by PKABA1. This protein (TaABF) has highest sequence similarity to the Arabidopsis ABA response protein ABI5. In two-hybrid assays TaABF bound only to PKABA1, but not to a mutant version of PKABA1 lacking the nucleotide binding domain, suggesting that binding of TaABF requires prior binding of ATP as would be expected for binding of a protein substrate by a protein kinase. TaABF mRNA accumulated together with PKABA1 mRNA during wheat grain maturation and dormancy acquisition and TaABFtranscripts increased transiently during imbibition of dormant grains. In contrast to PKABA1 mRNA, TaABF mRNA is seed specific and did not accumulate in vegetative tissues in response to stress or ABA application. PKABA1 produced in transformed cell lines was able to phosphorylate synthetic peptides representing three specific regions of TaABF. These data suggest that TaABF may serve as a physiological substrate for PKABA1 in the ABA signal transduction pathway during grain maturation, dormancy expression, and ABA-suppressed gene expression.
Short Integuments1/suspensor1/carpel Factory, a Dicer Homolog, Is a Maternal Effect Gene Required for Embryo Development in Arabidopsis
Authors: Golden Teresa A. , Schauer Stephen E. , Lang Jean D. , Pien Stéphane , Mushegian Arcady R. , Grossniklaus Ueli , Meinke David W. , Ray Animesh 
Published: October 2002

AbstractThe importance of maternal cells in controlling early embryogenesis is well understood in animal development, yet in plants the precise role of maternal cells in embryogenesis is unclear. We demonstrated previously that maternal activity of theSIN1 (SHORT INTEGUMENTS1) gene of Arabidopsis is essential for embryo pattern formation and viability, and that its postembryonic activity is required for several processes in reproductive development, including flowering time control and ovule morphogenesis. Here, we report the cloning of SIN1, and demonstrate its identity to the CAF (CARPEL FACTORY) gene important for normal flower morphogenesis and to the SUS1 (SUSPENSOR1) gene essential for embryogenesis.SIN1/SUS1/CAF has sequence similarity to the Drosophila melanogaster geneDicer, which encodes a multidomain ribonuclease specific for double-stranded RNA, first identified by its role in RNA silencing. The Dicer protein is essential for temporal control of development in animals, through the processing of small RNA hairpins that in turn inhibit the translation of target mRNAs. Structural modeling of the wild-type and sin1 mutant proteins indicates that the RNA helicase domain of SIN1/SUS1/CAF is important for function. The mRNA was detected in floral meristems, ovules, and early embryos, consistent with the mutant phenotypes. A 3.3-kb region 5′ of theSIN1/SUS1/CAF gene shows asymmetric parent-of-origin activity in the embryo: It confers transcriptional activation of a reporter gene in early embryos only when transmitted through the maternal gamete. These results suggest that maternal SIN1/SUS1/CAF functions early in Arabidopsis development, presumably through posttranscriptional regulation of specific mRNA molecules.
The KNAT2 Homeodomain Protein Interacts with Ethylene and Cytokinin Signaling
Authors: Hamant Olivier , Nogué Fabien , Belles-Boix Enric , Jublot Delphine , Grandjean Olivier , Traas Jan , Pautot Véronique 
Published: October 2002

Abstract
Using a transgenic line that overexpresses a fusion of the KNAT2 (KNOTTED-like Arabidopsis) homeodomain protein and the hormone-binding domain of the glucocorticoid receptor (GR), we have investigated the possible relations between KNAT2 and various hormones. Upon activation of the KNAT2-GR fusion, we observed a delayed senescence of the leaves and a higher rate of shoot initiation, two processes that are also induced by cytokinins and inhibited by ethylene. Furthermore, the activation of the KNAT2-GR fusion induced lobing of the leaves. This feature was partially suppressed by treatment with the ethylene precursor 1-aminocyclopropane-1-carboxylic acid, or by the constitutive ethylene response ctr1mutation. Conversely, some phenotypic traits of the ctr1mutant were suppressed by the activation of the KNAT2-GR fusion. These data suggest that KNAT2 acts synergistically with cytokinins and antagonistically with ethylene. In the shoot apical meristem, the KNAT2 gene is expressed in the L3 layer and the rib zone. 1-Aminocyclopropane-1-carboxylic acid treatment restricted the KNAT2 expression domain in the shoot apical meristem and reduced the number of cells in the L3. The latter effect was suppressed by the activation of the KNAT2-GR construct. Conversely, the KNAT2 gene expression domain was enlarged in the ethylene-resistant etr1-1 mutant or in response to cytokinin treatment. These data suggest that ethylene and cytokinins act antagonistically in the meristem via KNAT2 to regulate the meristem activity.
Molecular Characterization of the Cotton GhTUB1 Gene That Is Preferentially Expressed in Fiber
Authors: Li Xue-Bao , Cai Lin , Cheng Ning-Hui , Liu Jian-Wei 
Published: October 2002

Abstract
Each fiber of cotton (Gossypium hirsutum) is a single epidermal cell that rapidly elongates to 2.5 to 3.0 cm from the ovule surface within about 16 d after anthesis. A large number of genes are required for fiber differentiation and development, but so far, little is known about how these genes control and regulate the process of fiber development. To investigate gene expression patterns in fiber, a cDNA, GhTUB1, encoding β-tubulin was isolated from a cotton fiber cDNA library. The analyses of RNA northern-blot hybridization and reverse transcriptase-polymerase chain reaction demonstrated that GhTUB1 transcripts preferentially accumulated at high levels in fiber, at low levels in ovules at the early stage of cotton boll development, and at very low levels in other tissues of cotton. The correspondingGhTUB1 gene including the promoter region was isolated by screening a cotton genomic DNA library. To demonstrate the specificity of the GhTUB1 promoter, the 5′-flanking region including the promoter and 5′-untranslated region was fused with the β-glucuronidase reporter gene. The expression of the reporter chimera was examined in a large number of transgenic cotton plants. Histochemical assays demonstrated thatGhTUB1::β-glucuronidasefusion genes were expressed preferentially at high levels in fiber and primary root tip of 1- to 3-d-old seedlings and at low levels in other tissues such as ovule, pollen, seedling cotyledon, and root basal portion. The results suggested that the GhTUB1 gene may play a distinct and required role in fiber development. In addition, the GhTUB1 promoter may have great potential for cotton improvement by genetic engineering.
Changes in the Antioxidant Systems as Part of the Signaling Pathway Responsible for the Programmed Cell Death Activated by Nitric Oxide and Reactive Oxygen Species in Tobacco Bright-Yellow 2 Cells
Authors: de Pinto Maria Concetta , Tommasi Franca , De Gara Laura 
Published: October 2002

Abstract
Nitric oxide (NO) has been postulated to be required, together with reactive oxygen species (ROS), for the activation of the hypersensitive reaction, a defense response induced in the noncompatible plant-pathogen interaction. However, its involvement in activating programmed cell death (PCD) in plant cells has been questioned. In this paper, the involvement of the cellular antioxidant metabolism in the signal transduction triggered by these bioactive molecules has been investigated. NO and ROS levels were singularly or simultaneously increased in tobacco (Nicotiana tabacum cv Bright-Yellow 2) cells by the addition to the culture medium of NO and/or ROS generators. The individual increase in NO or ROS had different effects on the studied parameters than the simultaneous increase in the two reactive species. NO generation did not cause an increase in phenylalanine ammonia-lyase (PAL) activity or induction of cellular death. It only induced minor changes in ascorbate (ASC) and glutathione (GSH) metabolisms. An increase in ROS induced oxidative stress in the cells, causing an oxidation of the ASC and GSH redox pairs; however, it had no effect on PAL activity and did not induce cell death when it was generated at low concentrations. In contrast, the simultaneous increase of NO and ROS activated a process of death with the typical cytological and biochemical features of hypersensitive PCD and a remarkable rise in PAL activity. Under the simultaneous generation of NO and ROS, the cellular antioxidant capabilities were also suppressed. The involvement of ASC and GSH as part of the transduction pathway leading to PCD is discussed.