bluuebunny/crossref_metadata_2025 huggingface dataset:
The operations management research agenda: An update
Authors: Amoako‐Gyampah Kwasi , Meredith Jack R.
Published: October 2002

An agenda for operations management (OM) research was first proposed by Miller et al. in 1981. However, until Hill et al. examined recent Ph.D. dissertations in 1987, no other work on the agenda had been done. We take another look at the status of the OM research agenda from a slightly different perspective. The state of OM research in the United States is examined through a survey of published journal articles by OM researchers in the period 1982–1987. Overall, 362 journal articles were reviewed and classified into 17 categories.

The topical areas of technology and innovation, service operations, productivity, and manufacturing strategy suggested in the OM agenda for future research are now receiving some attention from OM researchers. We also compared our findings to the results of Chase's 1980 study and notice that, though statistically, OM research has changed since the time of Chase's study, the overall emphasis and orientation still appear to be the same.

To account for the publication time lag suffered by most journal articles, we also examined papers from the Decision Sciences Institute (DSI) proceedings for 1986 and 1987. The DSI proceedings were used as a surrogate measure of pipeline research. Statistically, the DSI proceedings appear to be different from contemporary OM research as published in the journals; the directions of the pipeline papers are more in agreement with the directions suggested in the OM agenda.

The final part of this study examined the types of research approaches used in the journal publications and compared them to those used in the DSI proceedings. There was no statistically significant difference between the research approaches used in the published and pipeline research. Our conclusion is that, though the OM agenda had suggested broadening the research strategies used in studying OM issues, the dominant strategies continue to be model and laboratory (primarily simulation) based.
A multivariate approach for assessing facility layout complexity
Authors: Makens Paul K. , Rossin Donald E , Springer Mark C.
Published: October 2002

The block layout problem is concerned with locating activities or departments of an organization such that those activities with the strongest interrelationships are closest to each other. Many solution procedures have been proposed for this problem. Research indicates that certain solution procedures perform reasonably well on certain data sets, but yield less desirable results on other problem sets with no clearly superior procedure emerging. Attention has focused on the complexity of the problem as the deciding factor. The measure of complexity most commonly used is the coefficient of variation of the problem data. As the coefficient of variation increases, it is suggested that human planners might be better able to handle the problem. The research in this area indicates mixed results.

It is argued in this paper that these measures are overly simplistic and cannot fully capture all of the aspects which determine problem complexity. A multivariate approach for measuring problem complexity is proposed. This approach is based upon the inherent structure of the problem itself. It is thus based on structural pattern recognition. An algorithm for determining the basic substructures and megastructure of a problem is proposed. Differences in performance of different solution procedures on different layout problems are examined using this multivariate approach. The approach is illustrated with example problems from the literature. An unpublished problem from a company is used to illustrate the utility of the megastructure as a guide for laying out a facility.
Load smoothing by the planning and order review/release systems: A simulation experiment
Authors: Melnyk Steven A. , Ragatz Gary L. , Fredendall Lawrence
Published: October 2002

Most research studies investigating the impact of Order Review/Release (ORR) mechanisms on shop performance have focused strictly on managing the flow of orders to the shop floor once they have been generated by the planning system. This approach ignores the possibility that the manufacturing planning system may be managing the incoming work flow so that peaks and valleys in the work load have been smoothed out.

This study shows, via a simple computer simulation of a random job shop, that such smoothing by the planning system can improve system performance and enhance the effects of Order Review/Release. The two ‘filtering’ mechanisms of planning system smoothing and Order Review/Release have a complementary impact on the system, with smoothing working to reduce flow time and flow time variability and ORR working to reduce work in process and work in process variability. The combination of smoothing with ORR results in shorter and more consistent lead times, lower and more stable work‐in‐process levels and better delivery performance. This results in a system which is very stable and predictable.

Further, the study shows that the combined effects of smoothing and ORR can improve the performance of simple shop floor dispatching rules like first come‐first served to the point where they are competitive with more sophisticated, due date oriented rules. This raises the possibility of simplifying control mechanisms on the shop floor by doing a better job of work load planning and order release.
Human resource issues in cellular manufacturing: A sociotechnical analysis
Authors: Huber Vandra L. , Brown Karen A.
Published: October 2002

Most research on cellular manufacturing (CM) has focused on the technical issues involved in converting functionally segregated operations into integrated multifunctional cells. Examples of these technical issues include classification methods, physical arrangements, methods for reducing set‐up time, and design of work flow sequence. By comparison, research on the human or social side of CM has been notably lacking. With the exception of anecdotal descriptions of CM concerns (Fazakerley (1974, 1976)), only two empirical studies have attempted to systematically pinpoint the nature of human resource issues in these settings (Brown and Mitchell (1991); Huber and Hyer (1985)). Consequently, the social system factors that support CM success are not well understood.

Based on sociotechnical systems (STS) theories, it is suggested that a complementary match between technical and social systems is needed to ensure optimization of CM implementations. One avenue for effecting social system change in response to technical innovations is through an organization's human resource system. Planning, job analysis, selection, training, reward structures, and employee relations practices may make a difference in the relative success of a CM conversion, and also may influence employee attitudes and quality of work life. These human resource practices provide support for attaining Cherns' (1978) nine STS principles—compatibility, minimal critical specification, the sociotechnical criterion, information flow, multifunctioning, boundary location, support congruence, human values, and incompletion. The integration of human resource management practices and STS theories provides implementation guidelines and also helps to reveal areas where research is needed.

Longitudinal and cross‐sectional field studies will be the methodologies of choice for assessing human resource issues in CM settings. For example, descriptive studies may assess job satisfaction, pay satisfaction, job content, or perceptions of performance obstacles. Of equal importance will be research which tests the effectiveness of various human resource practices (e.g., realistic job previews, training. team incentive systems) in CM settings. Dependent variables for these studies may include economic measures such as throughput time, quality, inventory levels, and employee turnover rates, as well as measures of employee attitudes and the time required for full CM implementation. Field research will improve our understanding of the human resource practices which are most likely to enhance CM implementations, and also will further our understanding of STS relationships.
Factory focus: Segmenting markets from an operations perspective
Authors: Berry William L. , Klompmaker Jay E. , Bozarth Cecil C. , Hill Terence J.
Published: October 2002

Market segmentation techniques are routinely used by marketers to divide markets into groups of customers showing similar buying behavior. This paper addresses the role of market differences as they affect the development of an appropriate operations strategy, specifically factory focus. It discusses the problem of segmenting markets with regard to operations capabilities, and the application of cluster analysis to market segmentation using operations variables.

We report on field research conducted to test this approach using actual operating data. The results demonstrate the feasibility of using market segmentation analysis to characterize the market served by a company in terms of the requirements placed on operations. We believe it is critical that marketing and operations managers understand and be able to relate to the different views of a market taken by the two functions. Different perspectives on market requirements, and an awareness of the capabilities required by the firm to support these requirements, are important preconditions for the development of coherent strategic plans for a company.
Design strategy and its interface with manufacturing and marketing: A conceptual framework
Authors: Fitzsimmons James A. , Kouvelis Panagiotis , Mallick Debasish N.
Published: October 2002

“Product design is a strategic activity, by intention or by default” (Whitney (1988)). An organization has to compete to ensure its survival and the dimensions of competition are cost, quality, reliability, flexibility, service, and speed of delivery. Major commitments to these dimensions are usually made during the design stage of the product. Unfortunately, we observe in most organizations a widening gap between design and other business functions (Meikle (1989)). This article attempts to bridge this gap by: (1) defining “design” as a strategic activity to facilitate its participation in the corporate debate, and; (2) presenting a conceptual framework which integrates design with manufacturing and marketing as equal partners to support the overall corporate mission.

In this article we examine the strategic nature of design. We define “design” and “design strategy” in a language that is familiar to business and present a conceptual framework that can be used to plan, implement, and control design activities strategically.

According to this framework all dimensions of competition can be expressed by two basic design variables, complexity and innovation. The design strategy formulation process consists of two stages. In stage one we position a design using complexity and innovation levels to identify threats and opportunities, to evaluate consistency of design strategies, and to obtain an aggregate measure of effort required to support a design strategy. In stage two we use the strategic insight gained in stage one to select an appropriate infrastructure to support our design objectives.

The framework presented in this article extends the manufacturing strategy framework by Hill (1989) to provide an effective interface between design, manufacturing, and marketing functions. We have used the dimensions of competition as the integrating force.

This article also provides a foundation on which future empirical and analytical research can be based. It emphasizes the need for strategic management of design activity instead of relegating design to a traditional reactive role. In this respect the framework is a significant step towards reducing the existing gap between design and the other business functions, and can help corporate strategists use design as a competitive weapon.
Setup cost reduction in the dynamic lot‐size model
Authors: Mekler Victoria A.
Published: October 2002

Recently, one primary focus of Operations Management has turned to setup reduction because of the growth of Just‐in‐Time(JIT) manufacturing. Porteus [1] and Billington [2] have developed optimal policies for calculating investment in setup reduction and lot‐size in the EOQ model when setup cost is some function of investment. Zangwill [3] has examined the effects of incremental setup cost reductions in the multi‐factility dynamic demand environment on costs and zeroinventory facilities. His focus is on obtaining zero‐inventory facilities and maximizing savings from lower setup costs without including the cost of such an event.

As an extension of these developments, we model the Wagner‐Whitin problem with a one‐time oportunity to invest in setup reduction. Setup cost is treated as a policy variable and defined as a function of the decision variable representing the annual amortized investment in setup cost reduction. We use an exponential setup reduction function, but speculate that the results also hold for other functions as well. In contrast to Zangwill, we take a direct approach by explicitly finding the optimal investment in setup cost reduction while generating an optimal lot‐sizing schedule. Solving a model that incorporates the trade‐off between investment and savings results in more realistic solutions. We use a golden section search and the Wagner‐Whitin algorithm to obtain solutions for lot‐size, setup cost, and the investment in setup reduction. This model is also formulated as a network to better illustrate the interaction between the decision variables. The network formulation can also be exploited to solve the problem with linear programming or network techniques.

Finally, we state and prove two theorems that hold for all setup reduction models whether they assume constant or dynamic demand. The first theorem asserts that optimal values for setupt cost and lot‐sizes stay fixed over a particular range of holding costs. The second theorem states that the optimal setup cost is independent of initial setup cost.
The relative significance of forecast errors in multistage manufacturing
Authors: Ritzman Larry P. , King Barry E.
Published: October 2002

It is intuitive that controlling forecast errors should result in better customer service and lower inventories. But forecast errors come from various sources. Multistage manufacturing experiences supply and lead‐time uncertainties as well as demand uncertainties, and manufacturing has more than one lever to pull when addressing these uncertainties. The relationship of forecast errors to manufacturing performance is not clear. Furthermore, the pursuit of forecast accuracy may not be the best use of managerial resources. In this study, using a many‐factored manufacturing simulation, we examine two components of forecast errors, the mix of special and standard products, lot‐sizing, and buffering policies as they affect inventories and customer service. Although most conclusions are situation dependent, reducing forecast bias is shown to be much preferred to reducing forecast variability, bias management is more important to on‐time delivery than to inventory reduction, and the value of such reductions is particularly important in situations where there are large lot‐sizes and small buffers.
A 3D model of the voltage‐dependent anion channel (VDAC)
Authors: Casadio Rita , Jacoboni Irene , Messina Angela , De Pinto Vito
Published: October 2002

Eukaryotic porins are a group of membrane proteins whose best known role is to form an aqueous pore channel in the mitochondrial outer membrane. As opposed to the bacterial porins (a large family of protein whose 3D structure has been determined by X‐ray diffraction), the structure of eukaryotic porins (also termed VDACs, voltage‐dependent anion‐selective channels) is still a matter of debate. We analysed the secondary structure of VDAC from the yeast Saccharomyces cerevisiae, the fungus Neurospora crassa and the mouse with different types of neural network‐based predictors. The predictors were able to discriminate membrane β‐strands, globular α‐helices and membrane α‐helices and localised, in all three VDAC sequences, 16 β‐strands along the chain. For all three sequences the N‐terminal region showed a high propensity to form a globular α‐helix. The 16 β‐strand VDAC motif was thus aligned to a bacterial porin‐derived template containing a similar 16 β‐strand motif. The alignment of the VDAC sequence with the bacterial porin sequence was used to compute a set of 3D coordinates, which constitutes the first 3D prediction of a eukaryotic porin. All the predicted structures assume a β‐barrel structure composed of 16 β‐strands with the N‐terminus outside the membrane. Loops are shorter in this side of the membrane than in the other, where two long loops are protruding. The shape of the pore varies between almost circular for Neurospora and mouse and slightly oval for yeast. Average values between 3 and 2.5 nm at the C‐carbon backbone are found for the diameter of the channels. In this model VDAC shows large portions of the structure exposed on both sides of the membrane. The architecture we determine allows speculation about the mechanism of possible interactions between VDAC and other proteins on both sides of the mitochondrial outer membrane. The computed 3D model is consistent with most of the experimental results so far reported.
The F‐helix of serpins plays an essential, active role in the proteinase inhibition mechanism
Authors: Gettins Peter G.W
Published: October 2002

Proteinase inhibition by serpins requires a 70 Å translocation of the proteinase, circumvention of the blocking helix F, and a crushing of the proteinase to render it catalytically incompetent. I propose that temporary displacement of the F‐helix during proteinase transit, and its subsequent return after complete passage of the proteinase, not only allows the proteinase to reach its final location, but provides an absolutely essential coupling mechanism for making the final proteinase crushing step energetically favorable. The F‐helix is therefore not a passive impediment to proteinase translocation, but a critical, active element in permitting the serpin inhibition mechanism to operate successfully.
Pure antiandrogens disrupt the recruitment of coactivator GRIP1 to colocalize with androgen receptor in nuclei
Authors: Karvonen U , Jänne O.A , Palvimo J.J
Published: October 2002

We have used confocal microscopy to elucidate the effects of antiandrogens on nuclear localization of the androgen receptor (AR) with its transcriptional coactivator GRIP1. We show that the agonist‐activated AR recruits GRIP1 to colocalize with the receptor in the nucleoplasm. By contrast, AR complexed to the antiandrogens hydroxyflutamide and bicalutamide fails to influence nuclear distribution of GRIP1. Likewise, the non‐steroidal antiandrogens prevent the agonist‐induced AR–GRIP1 colocalization from occurring. Androgen antagonists affect nuclear redistribution of AR–GRIP1 in a fashion that parallels their effects on the transcriptional activity of AR, in that the pure antagonists block GRIP1‐dependent activation of AR function, whereas the mixed antagonist/agonist cyproterone acetate promotes both AR‐driven redistribution of GRIP1 and activation of AR by GRIP1.
3‐Chloro‐DL‐alanine resistance by L‐methionine‐α‐deamino‐γ‐mercaptomethane‐lyase activity
Authors: Yoshimura Mamiko , Nakano Yoshio , Fukamachi Haruka , Koga Toshihiko
Published: October 2002

The antibacterial agent 3‐chloro‐DL‐alanine (3CA) is an inhibitor of peptidoglycan synthesis. Fusobacterium nucleatum and Porphyromonas gingivalis, the bacteria responsible for oral malodor, are shown to be resistant to 1 mM 3CA, whereas Streptococcus mutans and Escherichia coli are sensitive to this antibacterial agent at the same concentration. We isolated the 3CA resistance gene from F. nucleatum and showed that the gene encodes an L‐methionine‐α‐deamino‐γ‐mercaptomethane‐lyase that catalyzes the α,γ‐elimination of L‐methionine to produce methyl mercaptan. The enzyme also exhibits 3CA chloride‐lyase (deaminating) activity. This antibacterial agent is expected to be useful for specific selection of malodorous oral bacteria producing high amounts of methyl mercaptan.
Direct evidence for alteration of unfolding profile of a helical peptide by far‐ultraviolet circular dichroism aromatic side‐chain contribution
Authors: Banerjee Raja , Basu Gautam
Published: October 2002

Aromatic side‐chains are known to contribute to the far‐UV circular dichroism (CD) spectra of peptides and proteins. Among other things, this can significantly affect the measured helix propensities of amino acids [Chakrabartty et al., Biochemistry 32 (1993) 5560–5565]. In order to address how interfering side‐chain contributions can affect the backbone unfolding transition of a helical peptide, as monitored by [θ]222(molar ellipticity at 222 nm), we have studied the unfolding transition of a short designed (α‐amino isobutyric acid/alanine‐based) helical peptide containing an interacting Tyr residue. The guanidinium hydrochloride‐induced unfolding of the peptide, as monitored by [θ]222, showed the presence of a sharp transition superposed over a much broader transition. When the same experiment was performed with a similar peptide that lacked the interacting Tyr residue, the sharp transition disappeared and only the broad transition remained. The sharp transition was assigned to originate from the interacting Tyr side‐chain. This demonstrates that conformationally restricted aromatic side‐chains that interact with the helical backbone not only can alter the backbone far‐UV CD signal, they may also alter the unfolding profiles, monitored by far‐UV CD, rendering them unfit for a simple analysis for extracting the appropriate unfolding thermodynamic parameters.
The hydroxyphenylpyruvate dioxygenase from Synechocystis sp. PCC 6803 is not required for plastoquinone biosynthesis
Authors: Dähnhardt Dorothee , Falk Jon , Appel Jens , van der Kooij Tom A.W , Schulz-Friedrich Rüdiger , Krupinska Karin
Published: October 2002

The disruption of the Synechocystis open reading frame Δslr0090 encoding a gene with high homology to plant genes encoding 4‐hydroxyphenylpyruvate dioxygenase results in an impairment of tocopherol biosynthesis without affecting levels of plastoquinone, carotenoids and chlorophyll as well as cell growth and photosynthesis. Our results indicate that in Synechocystis in contrast to the situation in higher plants the 4‐hydroxyphenylpyruvate dioxygenase is not required for the synthesis of plastoquinone.
A simple and rapid procedure for the purification of synthetic polypeptides by a combination of affinity chromatography and methionine chemistry
Authors: Roggero M.A. , Servis C. , Corradin G.
Published: October 2002

Chemical synthesis of bioactive peptides has become a widespread and rapidly growing technique due to automated and efficient protocols for chain assembly. For most applications, the crude synthetic product must be purified to remove residual reactants, failure sequences and chemically modified peptide species. We propose here a method of universal applicability based on immobilized metal ion affinity chromatography, CNBr cleavage and use of reversible Met‐sulfoxide protection. With this method we were able to purify to homogeneity in high yield the PbCS 242–310 polypeptide corresponding to the C‐terminal region ofPlasmodium bergheiCS protein.
Melatonin prevents changes in microsomal membrane fluidity during induced lipid peroxidation
Authors: Garcı́a Joaquı́n J , Reiter Russel J , Guerrero Juan M , Escames Germaine , Yu Byung P , Oh Chang S , Muñoz-Hoyos Antonio
Published: October 2002

We tested the effect of melatonin on membrane fluidity in microsomes of a rat liver model in which lipid peroxidation was induced by the addition of FeCl3, ADP and NADPH. Membrane fluidity was monitored using fluorescence spectroscopy and lipid peroxidation was estimated by quantifying malonaldehyde (MDA)+4‐hydroxyalkenals (4‐HDA) concentrations following the induction of lipid peroxidation with and without pre‐incubation with melatonin (1 μM–3 mM). Membrane rigidity increased during induced lipid peroxidation while melatonin reduced in a concentration‐dependent manner both membrane rigidity and MDA+4‐HDA generation. Melatonin's protective effect may relate to its known ability to scavenge free radicals and function as an antioxidant.
Postimport methylation of the small subunit of ribulose‐1,5‐bisphosphate carboxylase in chloroplasts
Authors: Grimm Rudolf , Grimm Monika , Eckerskorn Christoph , Pohlmeyer Kai , Röhl Thomas , Soll Jürgen
Published: October 2002

Electron impact mass spectronomy analysis of the amino‐terminal amino acid of the small subunit (SSU) of ribulose‐1,5‐bisphosphate carboxylase (Rubisco) showed that the amino‐terminal methionine residue is post‐translationally modified to N‐methyl‐methionine. Modification of the amino‐terminal methionine residue was found in mature SSU proteins from the dicotyledonous plants pea and spinach as well as the monocotyledonous plants barley and corn. SSU methyltransferase is a soluble protein in the chloroplast stroma and accepts heterologously expressed non‐methylated SSU as a substrate using S‐adenosylmethionine as methyl‐group donor. We show that this modification occurs after post‐translational uptake of the precursor form of SSU into chloroplasts and processing to its mature size. This reaction represents a new step in the import and assembly pathway of Rubisco holoenzyme.
The regiochemical distribution of positive charges along cholesterol polyamine carbamates plays significant roles in modulating DNA binding affinity and lipofection
Authors: Geall Andrew J , Eaton Michael A.W , Baker Terry , Catterall Catherine , Blagbrough Ian S
Published: October 2002

We have quantified the effects of the regiochemical distribution of positive charges along the polyamine moiety in lipopolyamines for DNA molecular recognition. High affinity binding leads to charge neutralisation, DNA condensation and ultimately to lipofection. Binding affinities for calf thymus DNA were determined using an ethidium bromide displacement assay and condensation was detected by changes in turbidity using light scattering. The in vitro transfection competence of cholesterol polyamine carbamates was measured in CHO cells. In the design of DNA condensing and transfecting agents for non‐viral gene therapy, the interrelationship of ammonium ions, not just their number, must be considered.
Purification and functional reconstitution of a truncated human Na+/glucose cotransporter (SGLT1) expressed in E. coli
Authors: Panayotova-Heiermann Mariana , Leung Daisy W , Hirayama Bruce A , Wright Ernest M
Published: October 2002

A truncated human Na+/glucose cotransporter (C5, residues 407–664) was expressed and purified from Escherichia coli using a GST fusion vector and glutathione affinity chromatography. The truncated transporter (C5) was cleaved from GST‐C5 by Factor Xa proteolysis and purified by gel filtration chromatography. Up to 1 mg of purified GST‐C5 was obtained from 1 l bacterial culture. Reconstitution of both GST‐C5 and C5 proteins into lipid vesicles resulted in 2.5‐fold higher initial uptake rates of [3H]D‐glucose into C5‐proteoliposomes than into liposomes. Transport was stereospecific, saturable, and inhibited by phloretin. These properties are similar to those obtained for C5 in Xenopus laevis oocytes, and provide additional evidence that the five C‐terminal transmembrane helices in SGLT1 form the sugar translocation pathway.
The conserved undecapeptide shared by thiol‐activated cytolysins is involved in membrane binding
Authors: Jacobs T. , Cima-Cabal M.D. , Darji A. , Méndez F.J. , Vázquez F. , Jacobs A.A.C. , Shimada Y. , Ohno-Iwashita Y. , Weiss S. , de los Toyos Juan R.
Published: October 2002

Thiol‐activated cytolysins share a conserved hydrophobic, Trp‐rich undecapeptide that is suggested to be involved in membrane binding and intercalation. The neutralizing monoclonal antibody PLY‐5 recognizes all members of this toxin family and peptide mapping assigned its epitope to the undecapeptide motif. This antibody inhibited binding of the toxins to host cell membranes and the epitope was no longer available for binding when a preformed toxin/membrane complex was tested. These results confirm the model of cytolysin binding suggested by structural data.
Evidence that fructose 1,6‐bisphosphate specifically protects the α‐subunit of pyrophosphate‐dependent 6‐phosphofructo‐1‐phosphotransferase against proteolytic degradation
Authors: Wang Yue-Hao , Shi Jiao-Nai
Published: October 2002

Pyrophosphate‐dependent 6‐phosphofructo‐1‐phosphotransferase (PFP) consists of α (regulatory) and β (catalytic) subunits. The α‐subunit was previously reported to be much more susceptible to tryptic digestion than the β‐subunit. In this study, ligand‐induced protection of PFP subunits against proteolysis by subtilisin was investigated in vitro and the data obtained demonstrated that fructose 1,6‐bisphosphate (Fru‐1,6‐P2), while exerting negligible effect on the β‐subunit, remarkably protected the α‐subunit against proteolytic degradation. Western blot analysis revealed a good correlation between the Fru‐1,6‐P2 concentration and the degree of corresponding protection on the α‐subunit against proteolysis. In contrast, none of other examined ligands including fructose 2,6‐bisphosphate, fructose 6‐phosphate and pyrophosphate had such protection on the α‐subunit. This finding (1) indicates that the stability of the α‐subunit can be selectively increased by Fru‐1,6‐P2, and (2) suggests that Fru‐1,6‐P2 is likely a special effector of the α‐subunit.
The effects of environmental factors on the design of master production scheduling systems
Authors: Lin Neng‐Pai , Krajewski Lee , Leong G.Keong , Benton W.C.
Published: October 2002

In uncertain environments, firms often use a rolling schedule to implement a master production schedule (MPS). The rolling schedule involves replanning the MPS periodically and freezing a portion of the MPS in each planning cycle. Two important decisions which have a significant impact on the cost performance of a rolling schedule are the choice of a replanning interval (R), which determines the replanning frequency of the MPS, and the selection of a frozen interval (F), which represents the number of periods the MPS is frozen in each planning cycle. The determination of the appropriate F and R values has been an important research issue, especially in an uncertain environment.

This paper examines the effects of environmental factors such as cost structure, bill of material (BOM) structure, cumulative lead time, magnitude of MPS change costs, and the magnitude of forecast error on the choice of F and R for a single end item in an uncertain environment where a rolling schedule is used. Results of our investigation show that the choice of F affects total system costs per period (TC) but the effects of the choice of R on TC is situational. In addition, the analysis indicates that the magnitude of the MPS change costs, the BOM structure, and the cumulative lead time of the product are important considerations in the design of MPS systems. Results also show that the magnitude of the forecast errors and the cost structure play relatively minor roles in the choice of F and R. We also show that even when MPS change costs are high, greater freeze intervals and more frequent replanning may be cost effective.
Fringe phenotypes in autism: a review of clinical, biochemical and cognitive studies
Authors: Goussé Véronique , Plumet Marie-Hélène , Chabane Nadia , Mouren-Siméoni Marie-Christine , Ferradian Nathalie , Leboyer Marion
Published: October 2002

Progress in identifying the genetic vulnerability factors in autism requires correct identification of the inherited phenotype(s). This can be achieved not only by the accurate description of the affected subject but also by the identification of vulnerability traits in non-affected relatives of autistic probands. This review will focus on this last strategy and principally on clinical, biochemical and cognitive traits.
Spectral sensitivities of five marine decapod crustaceans
and a review of spectral sensitivity variation in relation to habitat
Authors: Johnson Magnus L. , Gaten Edward , Shelton Peter M.J.
Published: October 2002

The spectral sensitivities of five species of decapod crustaceans have been determined by electroretinogram measurements. Their spectral sensitivities conform to the general picture for marine crustacea with high sensitivity to blue-green wavelengths and some showing sensitivity to violet/near ultraviolet. Two deep-water species (Paromola cuvieri and Chaceon (Geryon) affinis) have spectral sensitivity maxima below 500 nm, whereas the three coastal species examined (Crangonallmani, Pandalus montagui and Nephrops norvegicus) are maximally sensitive to light of longer wavelengths (510 to 525 nm).
First occurrence of egg masses of Loligo forbesi (Cephalopoda: Loliginidae) in deep waters of the Aegean Sea
Authors: Salman A. , Laptikhovsky V.
Published: October 2002

Egg masses of Loligo forbesi were encountered for the first time from a depth of 730 m at Gökova Bay (southern Aegean Sea), extending the known spawning depth in the Mediterranean Sea.
Expectations of inter-generational reciprocity among older Greek Cypriot migrants in London
Authors: CYLWIK HELEN
Published: October 2002

This article explores the expectations of inter-generational reciprocity amongst older Greek Cypriot women and men living in London from the parents' perspective. Participants engaged in a number of discourses when talking about children. These discourses, which were culturally determined, underpinned parental expectations of inter-generational reciprocity. On a day-to-day basis, older Greek Cypriots were both givers and receivers of help. Gender differences, rather than differences in age or marital status, were evident in both the giving and receiving of help. Parents' perceptions of parent–child relations were not affected by migration, and were pivotal to wellbeing in later life. The bonds between parents and children were perceived as being strong and enduring, although changing throughout the lifecourse.
The Long Road to Healing: From the TRC to TfD
Authors: Marlin-Curiel Stephanie
Published: October 2002

The South African Truth and Reconciliation Commission has inspired several pieces of theatre that emphasize the powerful aesthetics of testimony and the challenges of an ethical response. While many of these are experimental plays with high production values and engage with Ålite liberal audiences on a metaphoric level, the theatrical space remains a comment upon, but does not merge with, everyday reality. The focus here is on three plays in which audiences are not watching an ‘other’ but are watching themselves. They are brought on a journey of healing as a community. That Spirit by Mina Nawe, Thetha Ngikhulume (‘Speak so that I may speak’) by Bongani Linda and The Victory Sonqoba Theatre Company and The Story I am About to Tell by Khulumani Support Group belong to the category of Theatre for Development (TfD). TfD most often stages intellectual debates on social and political issues affecting a particular, usually geographically defined, community. However, rather than exploring the socio-political aspects of the TRC, these plays focus on the deep emotional trauma that remains with survivors as the TRC goes about ‘healing the nation’. This article draws on the theories of social change associated with TfD, Augusto Boal's theories of theatre as therapy, psychologists’ theories of post-conflict recovery, and, theories of restorative justice to evaluate the healing potential of both the TRC and TfD.
Routes for salmonella contamination of poultry meat: epidemiological study from hatchery to slaughterhouse
Authors: HEYNDRICKX M. , VANDEKERCHOVE D. , HERMAN L. , ROLLIER I. , GRIJSPEERDT K. , DE ZUTTER L.
Published: October 2002

Data were collected on the prevalence of salmonella at different stages during the life cycle of 18 broiler flocks on different farms as well as during slaughter in different poultry slaughterhouses. For the isolation of salmonella, the highest sensitivity (93.9%) was obtained by enrichment in the semi-solid agar Diasalm. The ‘overshoe method’ utilizing several pairs of overshoes provided the highest sensitivity for determining the salmonella status of the broilers during rearing. A clear decrease of the relative importance of the first production stages was demonstrated for the salmonella contamination of the end product, whereas horizontal transmission of salmonella to broilers during rearing and to broiler carcasses in the slaughterhouse was shown to be the main determinative factor. Ten of the 18 flocks received a salmonella positive status with the highest shedding occurring during the first 2 weeks of rearing. The shedding of the animals was significantly negatively influenced by the use of subtherapeutic or therapeutic doses of antibiotics. The intake of portable material in the broiler house was identified as the most important risk factor for horizontal transmission. Significant associations were found between the contamination level of a flock and hygiene of the broiler house, feed and water in the broiler house and both animal and non-animal material sampled in the environment. No correlation was found between contamination during the rearing period and contamination found after slaughtering. The presence of faecal material in the transport crates and predominantly the identity of the slaughterhouse seemed to be the determining factors for carcass quality. Improved hygiene management during transport of broilers and in some slaughterhouses could significantly reduce the risk of salmonella contamination of poultry meat.
Radiological assessment of male erectile dysfunction and subfertility
Authors: Jones RWA , Kabala J , Gingell JC , Persad RA
Published: October 2002

Interest in the investigation of male erectile dysfunction and male factor infertility has risen in recent years, due in part to the increased sophistication and high profile of new treatments associated with these conditions. The assessment and management of men presenting with erectile or fertility problems are usually achieved by collaboration between urology and other specialties. A radiologist is often a vital member of this multidisciplinary team. This article will review the imaging modalities currently available and discuss their current role in the investigation of these two key areas of andrology.
Lower and Upper Bounds
for the Time Constant of
First-Passage Percolation
Authors: ALM SVEN ERICK , PARVIAINEN ROBERT
Published: October 2002

We present improved lower and upper bounds for the time constant of first-passage
percolation on the square lattice. For the case of lower bounds, a new method, using
the idea of a transition matrix, has been used. Numerical results for the exponential and
uniform distributions are presented. A simulation study is included, which results in new
estimates and improved upper confidence limits for the time constants.
Progress illuminating the world: street lighting in Santiago, Valparaiso and La Plata, 1840–90
Authors: Martland Samuel J.
Published: October 2002

By examining a major port, a capital and a planned model city, this article links the diffusion of street lighting in nineteenth-century Latin America to changing notions of the night and of technology. In these three cities, lighting emerged as an eminently flexible strategy of modernization. Street lighting attracted urban officials and elite residents, who could economically install it as an antidote to crime, a complement to night life, or an emblem of progress.
The origin of Definite Article Reduction in northern English dialects: evidence from dialect allomorphy
Authors: Jones Mark J.
Published: October 2002

The phenomenon of Definite Article Reduction (DAR) is the realization of the definite article in northern British English dialects in a range of vowel-less forms, usually written t' in literature. The origin of DAR is assumed to be the assimilation of the initial fricative of the Middle English definite article þe to produce a te form, a sound change recorded for many dialects of Middle English. This article examines the validity of this hypothesis by analysing the distribution of fricative allomorphs in the modern dialects in comparison with the details of the Middle English change. The predicted distribution of fricative forms is not found at most localities, indicating that the development hypothesis is incorrect, but the available data are too scanty to suggest an alternative model.
The Rat Glomerular Filtration Barrier Does Not Show Negative Charge Selectivity
Authors: SCHAEFFER RICHARD C. , GRATRIX MAX L. , MUCHA DAVID R. , CARBAJAL JOSÉ M.
Published: October 2002

Objective: To characterize the effects of size, shape, and negative charge on the transport of macromolecules across the glomerular capillary wall by using the sieving curves (fractional clearance vs. solute molecular radii) of fluorescent polydispersed polysaccharide tracers.

Methods: Glomerular fractional clearances (FC) were measured with fluorescent neutral [isoelectric point (pI) = 7.3 ± 0.2] and negatively charged (pI = 3.5 ± 0.4) dextrans (DEX) in comparison with negatively charged (pI = 4.8 ± 0.3) hydroxy ethyl starch (HES) and (pI = 4.6 ± 0.1) bovine serum albumin (BSA) in Sprague‐Dawley and Fischer 344/Brown Norway rats. FCs (n= 53) were measured by using the urinary clearance of 14C‐inulin to determine the glomerular filtration rate. The relative uptake of each fluorescent probe by endothelial and renal proximal tubule epithelial (LLC‐PK1) cells, in vitro, was measured microscopically by using a cooled (−25 °C) CCD camera.

Results: The sieving curves for randomly coiled neutral and negatively charged DEX probes were identical. These FC values were 6‐fold greater than those for HES and 200‐fold above similarly sized fluorescent BSA. The polysaccharide probes did not show significant binding to serum proteins. The uptake of BSA by LLC‐PK1 cells was 20‐ to 100‐fold greater than that for neutral or negatively charged macromolecules.

Conclusions: These findings indicate that the rat glomerular filtration barrier restricts the transport of polysaccharide macromolecules as a function of their size and configuration but not negative charge.
CO2-Triggered Chloride Release from Guard Cells in Intact Fava Bean Leaves. Kinetics of the Onset of Stomatal Closure
Authors: Hanstein Stefan M. , Felle Hubert H.
Published: October 2002

The influence of CO2 on Cl− release from guard cells was investigated within the intact leaf by monitoring the Cl− activity in the apoplastic fluid of guard cells with a Cl−-sensitive microelectrode. In illuminated leaves adapted to a CO2 concentration within the cuvette of 350 μL L−1, an increase of 250 μL L−1CO2 triggered a transient rise in the apoplastic Cl− activity from 3 to 14 mm within 10 min. This Cl− response was similar to the Cl−efflux evoked by turning off the light, when the substomatal CO2 was kept constant (CO2 clamp). Without CO2 clamp, substomatal CO2 increased by 120 μL L−1 upon “light off.” The response to an increase in CO2 within the cuvette from 250 to 500 μL L−1 in dark-adapted leaves was equivalent to the response to an increase from 350 to 600 μL L−1 in the light. No Cl− efflux was triggered by 2-min CO2 pulses (150–800 μL L−1). After a switch from 350 μL L−1 to CO2-free cuvette air, the guard cells were less sensitive to a rise in CO2 and to light off, but the sensitivity to both stimuli partially recovered. Changes in CO2 also caused changes of the guard cell apoplastic voltage, which were generally faster than the observed Cl−responses, and which also promptly occurred when CO2 did not initiate Cl− efflux. The comparatively slow activation of Cl− efflux by CO2 indicates that an intermediate effector derived from CO2 has to accumulate to fully activate plasma membrane anion channels of guard cells.
Phase-Specific Circadian Clock Regulatory Elements in Arabidopsis
Authors: Michael Todd P. , McClung C. Robertson
Published: October 2002

We have defined a minimal Arabidopsis CATALASE 3(CAT3) promoter sufficient to drive evening-specific circadian transcription of a LUCIFERASE reporter gene. Deletion analysis and site-directed mutagenesis reveal a circadian response element, the evening element (EE: AAAATATCT), that is necessary for evening-specific transcription. The EE differs only by a single base pair from the CIRCADIAN CLOCK ASSOCIATED 1-binding site (CBS: AAAAAATCT), which is important for morning-specific transcription. We tested the hypothesis that the EE and the CBS specify circadian phase by site-directed mutagenesis to convert theCAT3 EE into a CBS. Changing the CAT3 EE to a CBS changes the phase of peak transcription from the evening to the morning in continuous dark and in light-dark cycles, consistent with the specification of phase by the single base pair that distinguishes these elements. However, rhythmicity of the CBS-containing CAT3 promoter is dramatically compromised in continuous light. Thus, we conclude that additional information normally provided in the context of a morning-specific promoter is necessary for full circadian activity of the CBS.
Down-Regulation ofTM29, a TomatoSEPALLATAHomolog, Causes Parthenocarpic Fruit Development and Floral Reversion
Authors: Ampomah-Dwamena Charles , Morris Bret A. , Sutherland Paul , Veit Bruce , Yao Jia-Long
Published: October 2002

We have characterized the tomato (Lycopersicon esculentum Mill.) MADS box gene TM29 that shared a high amino acid sequence homology to the ArabidopsisSEP1, 2, and 3(SEPALLATA1, 2, and 3) genes. TM29 showed similar expression profiles toSEP1, with accumulation of mRNA in the primordia of all four whorls of floral organs. In addition, TM29 mRNA was detected in inflorescence and vegetative meristems. To understandTM29 function, we produced transgenic tomato plants in which TM29 expression was down-regulated by either cosuppression or antisense techniques. These transgenic plants produced aberrant flowers with morphogenetic alterations in the organs of the inner three whorls. Petals and stamens were green rather than yellow, suggesting a partial conversion to a sepalloid identity. Stamens and ovaries were infertile, with the later developing into parthenocarpic fruit. Ectopic shoots with partially developed leaves and secondary flowers emerged from the fruit. These shoots resembled the primary transgenic flowers and continued to produce parthenocarpic fruit and additional ectopic shoots. Based on the temporal and spatial expression pattern and transgenic phenotypes, we propose that TM29functions in floral organ development, fruit development, and maintenance of floral meristem identity in tomato.