bluuebunny/crossref_metadata_2025 huggingface dataset:
PDF versus LP: An empirical aggregate planning comparison
Authors: Holt Jack A.
Published: October 2002

Production Decision Framework (PDF) is a recently introduced heuristic method for solving the aggregate planning problem. The algorithm was developed and tested over a wide range of deterministic demand patterns and cost parameters. The decision by Wayn‐Tex Inc., to adopt the methodology provided a real world opportunity to evaluate the performance of PDF under uncertainty over a one year's operating period.

This paper concentrated on a study of (1) the effectiveness of the model in selecting a suitable rolling planning horizon, and (2) the performance of PDF as compared to a linear program solution using the same length horizon. The monthly sales forecast used in the study, developed by the sales department, took into consideration trend, seasonality, and known market conditions. The results were gratifying. Management has indicated their desire to continue using PDF as a guide in the production planning process through the use of the computerized program available.
The effects of input control in a simple scheduling model
Authors: Baker Kenneth R.
Published: October 2002

Input control is a generic procedure for smoothing production workload by delaying work during intervals of heavy load. While input control techniques have several practical benefits, they also have an inherent disadvantage. By restricting the set of jobs available for scheduling, an input control procedure removes some of the scheduling options that would otherwise be available. This paper examines the impact of such a procedure in a simple simulation model.

The simulation model represents a production shop in a simplified way, as a single machine, but the production control system has three distinct parts. The first part assigns due‐dates to customer orders, taking into consideration the size of each job and the workload in the shop. The second part is a job releasing rule that implements input control. The third part is a priority dispatching procedure that is aimed at meeting due‐dates. By representing this three‐part control system the model provides an opportunity to explore the interdependence between input control and other control procedures.

Reinforcing previous research, the simulation experiments confirm that modified due‐date priorities perform more effectively than other basic priority rules when performance is measured by average tardiness. Moreover, the experiments indicate that performance under the modified due‐date regime is never improved by the use of input control. On the other hand, with dispatching rules that rely on shortest‐first or critical ratio priorities, the experiments indicate that input control is sometimes advantageous. The effects of input control on scheduling performance thus appear to be somewhat complicated, and further experiments were designed to explore some of the relationships involved. The principal finding, however, provides a warning that input control can be counterproductive.
Integer goal programming for multistage lot sizing: Experimentation and implementation
Authors: Vickery Shawnee K. , Markland Robert E.
Published: October 2002

This article considers the issues involved in implementing a large‐scale multistage lot sizing model in a pharmaceutical manufacturing environment, and reports on a series of sensitivity experiments that subsequently examined the critical impacts of system capacity and inventory policy on the specification of a multistage schedule. The model was initially developed as an aggregate scheduling aid for a class of tablet pharmaceuticals. The manufacture of tablet products is a serial‐type process characterized by batch flow. The model placed multiple resource capacity restrictions on various stages of the multistage system to ensure the feasibility of the resultant schedules. Difficulties in estimating penalty costs for shortages were circumvented by employing a multi‐objective formulation of the lot‐sizing problem.

Various obstacles encountered during the implementation process are discussed. Model implementation encompassed the development of an approximation algorithm for efficiently solving the large‐scale problem. The performance of the algorithm was evaluated by examining the closeness to optimality of the solutions obtained using the procedure. Performance statistics are presented for the sensitivity experiments discussed herein. Another essential aspect of implementation involved the timely revision of model input parameters. This facet of implementation proved to be at least as important to management as the efficient provision of a “good” solution.

Model experimentation centered on variations in the capacities of bottleneck resources and changes in target inventory parameters whose values are predetermined by company policy. The first set of experiments was designed to demonstrate the importance of system capacity to the lot‐sizing process and to illustrate that the location of a system bottleneck can vary over time as a function of both internal and external factors. The results indicated that lot‐sizing procedures that fail to incorporate capacity information or that focus on a single bottleneck production stage in order to schedule production are severely limited with respect to practical and/or long‐term applicability.

The final set of inventory‐related experiments indicated that the specification of target ending inventory levels was a crucial factor in the lot‐sizing process. The determination of appropriate target levels must reflect the inherent trade‐off between the objective of minimizing shortages and the desire to avoid excessive inventory accumulations. The generation of usable model information was found to be contingent upon the realistic definition of target level parameters.
A reformulation of the aggregate planning problem
Authors: Schroeder Roger G. , Larson Paul D.
Published: October 2002

This article proposes a reformulation of the aggregate planning problem which more closely agrees with situations frequently encountered in practice. The proposed reformulation assumes that a firm's production planners want to determine the expected service and inventory levels for a given production profile in the face of uncertain seasonal demand. By using several different production profiles that are each consistent with the firm's staffing, subcontracting, and overtime policies, it is possible to pick the profile that best meets the firm's preferences for service level and inventory turns. Actually, the trade‐offs between inventory and service levels are examined so that an informed choice can be made by all of those concerned.

One of the advantages of the proposed model is that communications can be established among production, marketing, and finance managers who often have conflicting goals. Also, levels for inventory turns, service, and production can be set that are consistent with each other. Furthermore, several alternative production profiles can be examined in a relatively short time through the use of the simulation model proposed.

An application of the model to the Wagner Spray Tech Company, a producer of painting equipment, is presented. In this particular case, where forecasting errors are quite high, some of the potential uses of the model are presented. Also, reasons are given why this particular reformulation of the aggregate planning problem was found to be useful.
The effect of lead‐time variability: The case of independent demand
Authors: Bagchi Uttarayan , Hayya Jack C. , Chu Chao‐Hsien
Published: October 2002

We show in this study, through analysis and examples, the impact on stockouts and stockout risk if the variability of lead time in independent demand systems is ignored. In calculating safety stocks, we recommend that the compound distribution of demand during lead time, or a good approximation to it, be used. We motivate the article by a case study on lead‐time variability at the U.S. Air Force and show the impact of lead‐time variability by means of numerical examples and by marginal analysis. Having established that it is essential to consider lead‐time variability, we take advantage of theoretical developments and show how to calculate reorder points and safety stocks in some common situations.

It is important to use the proper form for the compound distribution of demand during lead time. A normal approximation to it will often yield significant errors. This is because the true distribution is usually very much skewed to the right.
The use of cost‐based priorities in random and flow shops
Authors: Scudder Gary D. , Hoffmann Thomas R.
Published: October 2002

This article evaluates the use of cost information for establishing priorities in a job shop. Most traditional research in the area of job shop scheduling uses only time‐oriented rules and performance criteria when in reality, minimizing total cost is the most appropriate objective.

Utilizing a simulation model of randomly‐routed and flow job shops, several priority rules are evaluated on the basis of time performance, primarily on‐time completions, as well as on the basis of cost performance: the minimization of work‐in‐process (WIP) investment. The priority rules use either time information only, cost or value information only, or both types of information in a composite manner. An additional concept examined is that of the speed of a job relative to its due date. Speed is examined for different profitability classes of jobs: high, medium, and low. It is often important that high profit jobs are completed on time, while low profit jobs may not be as critical.

The priority rules are simulated at four utilization levels and several replications are made to make statements about the statistical significance of the results. The results show that a time rule, such as critical ratio, performs poorly on cost measures, moves high and low profit jobs indiscriminately, and completes significantly fewer jobs on time at high utilization levels than the cost rules examined. One of the cost rules that utilizes the value added to a job is the best performer in terms of cost and does quite well in completing jobs on time.
Yield management: A tool for capacity‐considered service firms
Authors: Kimes Sheryl E.
Published: October 2002

Airlines typically sell their seats for a variety of different fares. If customers make reservations early, low fares might be available, but if customers call at the last minute, they will probably have to pay the full fare. Since deregulation, early all airlines have been using a technique called yield management. Yield management allows the airlines to allocate their fixed capacity of seats in the most profitable manner possible. Since the airline's inventory of seats is perishable, the airlines must have a method of quickly and accurately allocating potential demand to capacity. The airline industry has been in the forefront of using management, but yield management has potential application to any firm constrained by capacity. Other services which have adopted yield management include the lodging, rental car, delivery service, rail and cruise line industries.

The objective of yield management is to maximize the revenue or yield of the firm. A good yield management system will help the firm decide how much of each type of inventory (whether it be seats on an airplane, rooms in a hotel, or cars in a rental car fleet) to allocate to different types of demand. This article attempts to structure the concept of yield management by reviewing current literature, classifying types of solution approaches, discussing the managerial implications of yield management and presenting a future research agenda. While corporate research on yield management has been performed, most firms are understandably reluctant to share the results of their research with others. Operations management researchers could assist small and medium sized capacity‐constrained firms by developing simple and accurate yield management techniques. The intent of the paper is to focus attention n the yield management and stimulate practical and theoretical research in this area.
Time and product variety competition in the book distribution industry
Authors: Lindsley William B. , Blackburn Joseph D. , Elrod Terry
Published: October 2002

Product variety and time have emerged as prominent dimensions in global competition. Marketers have emphasized the strategic advantages accruing from offering increased variety: on the other hand, operations managers have stressed reduced operations cycle times and faster response times to customer needs. Although substantial documentation supports the impact of such activities on costs, the only empirical evidence concerning actual rewards in the marketplace from such strategic endeavors is anecdotal.

This study of the book distribution industry demonstrates a two‐phase methodology for valuing the rewards from faster response and improved variety. First an industry analysis was conducted to determine at a macro level how time and variety have been treated strategically and how it has affected the industry. The conclusion was that the very existence of the industry depends on the ability of these firms to offer a greater variety of titles shipped in smaller quantities in a relatively rapid fashion. Within the industry, those who can do this best have increased their market share substantially.

To quantify the potential rewards accruing to time‐based and variety‐based strategies, conjoint (or trade‐off) analyses were conducted via telephone to estimate the specific trade‐offs that retailers were willing to make among price, delivery time, and product variety. By understanding the relative value of different services or attributes to the consumer (in this case the book retailer), the impact of changing these services by either the firm or one of its competitors can be evaluated. For example, in our study, to overcome retailer's loyalty to a competitor, distributors would need to deliver one day faster than the average and fill about 3% more of the retailer's title needs. Similarly, one can determine what order fill rate increase or delivery time reduction would be necessary to offset a specific price increase and not lose customers.

In conclusion, the empirical research confirms the importance of time and variety as critical strategic dimensions. The emergence of a distributor that distinguishes itself from the competition along one or both these dimensions can alter the structure of the industry. Consequently, managers need to be cognizant of the relative values of time and variety in configuring their distribution strategy.
A systematic simulation approach for the design of JIT manufacturing systems
Authors: Abdou G. , Dutta S.P.
Published: October 2002

The paper provides a simulation model for kanban‐based scheduling in a multi‐stage, multi‐product manufacturing system. The model assists managers in determining the number of circulating kanbans and the corresponding container capacity. Each part is analyzed separately to find the optimum interarrivai time of the material handler, the optimum container capacity and the optimum number of kanbans. The analysis is based on the relationships between the overall cost and interarrivai times of each of these three input variables. Possible combinations of lot sizes are also investigated with the objective of reducing the number of such mixes. The results are used as an input for the multi‐product multistage simulation model to determine the best policy of mixed container capacities and number of kanbans. It is demonstrated that, given a set of operational conditions, a better design of a just‐in‐time manufacturing system can be attained through the application of the proposed simulation model.
A resource dependence perspective of Just‐in‐Time purchasing
Authors: Handfield Robert B.
Published: October 2002

A substantial body of literature in operations management has emphasized the importance of establishing “Just‐in‐Time” (JIT) purchasing with suppliers in order to reduce inventory levels, reduce inspection and produce better products. This issue is paralleled in resource dependence theory, which predicts how organizations respond to uncertainty within their external environment. The current research proposes a model which uses resource dependence to explain how and why purchasing is moving towards JIT, thereby bridging the fields of operations management and organization theory. The model proposes that supply base reduction is a response to increased uncertainty in demand and that JIT is preceded by greater information sharing with fewer suppliers. Further, the success of JIT purchasing systems is sustained through reduced transaction uncertainty with critical suppliers. These hypotheses are embodied in a path analysis model, which is tested for the existence of causal linkages between the constructs. The path model was tested using data collected from interviews with production, purchasing and engineering personnel at forty Make‐to‐Order manufacturing facilities. The results of the study support the idea that purchasing departments in Make‐to‐Order firms are likely to reduce the number of critical suppliers in response to uncertainty in demand. Further, evidence of the relationship between information sharing and supply base reduction was established and information sharing was shown to be an antecedent to JIT purchasing. The hypothesis that supply base reduction is an antecedent to JIT was not supported. However, the results suggest that the two policies are complementary, in that a coordinated program of both JIT purchasing and supply base consolidation can lead to significant reductions in transaction uncertainty
The effects of lot sizing and dispatching on customer service in an MRP environment
Authors: Gardiner Stanley C. , Blackstone John H.
Published: October 2002

Results are presented of a simulation analysis of a hypothetical fabrication and assembly shop controlled by material requirements planning. The purpose of the study is to investigate the impact of lot sizing on the customer service performance of dispatching techniques in an MRP‐controlled assembly job shop operating near capacity. Six dispatching techniques are compared based on the tardiness of customer orders under four lot‐sizing techniques, two levels of demand, and two levels of nervousness. The study is conducted with a stable product mix, limited production capacity, and fixed routings. Random shifts in short‐term product mix cause short‐term bottlenecks, but one of the 15 work stations has less than 10% idle time and is the most commonly encountered bottleneck.

The interaction of lot‐sizing and dispatching techniques was found to be a function of capacity utilization, a factor influenced by demand and nervousness level. Under low demand, earliest job due date yielded the best performance with regard to the percentage of tardy orders, average order tardiness, and maximum order tardiness. Under high demand, earliest job due date performed best with respect to average order tardiness and maximum order tardiness, but the best dispatching technique with respect to percentage of tardy orders depended on the lot‐sizing technique and the nervous‐ness level. Under high demand and high nervousness, effective capacity decreased and queues increased with economic order quantity, period order quantity, or least total cost. Economic order quantity generated the smallest batches. Period order quantity and least total cost generated extra set‐ups under high nervousness. Use of either of the three lot‐sizing techniques at high demand and high nervousness forced a choice between a dispatching technique that yields a low percentage of orders tardy (earliest modified operation due date) and one that generates low maximum order tardiness (earliest job due date). The Silver‐Meal heuristic consumed less effective capacity than the other lot‐sizing techniques. Using Silver‐Meal at high demand and nervousness, earliest job due date performed best with respect to each tardiness measure.

The bottleneck causes the plant to behave like a single machine shop. Since large queues are maintained at the bottleneck, that is where the choice of dispatching technique is critical. Earliest due date minimizes the percentage of tardy orders. Earliest modified operation due date, operating like the shortest processing time rule, minimizes the percentage of tardy orders, but maximum tardiness is high. These results may stimulate new interest in single‐machine scheduling.

The combination of least total cost and earliest job due produced the best overall performance at low demand. At high demand, Silver‐Meal and earliest job due date achieved the best performance.
A comparison of resource allocation and activity scheduling rules in a dynamic multi‐project environment
Authors: Yang Kum‐Khiong , Sum Chee‐Chuong
Published: October 2002

The use of a dual‐level structure in managing the use of resources in a multi‐project environment involves two sets of decisions. Resource allocation decisions, usually controlled by a central authority, determine the allocation of resources among projects such that resources are allocated to the critical projects. Once assigned to a project, the resources are managed by an independent project manager who schedules the activities within his project using only the resources assigned to him. This paper evaluates the relative performance of four resource allocation priority rules and six resource transfer rules in conjunction with two activity scheduling rules. The results show that the First in System First Served resource allocation priority rule dominates over the other three proposed resource allocation priority rules with the lowest project tardiness, flowtime, and lateness standard deviation. Further evaluation of the resource transfer rules shows that additional resources should only be transferred into a project just‐in‐time of expected use, and idle resources which are expected to be utilized within a time period of not longer than two times the resource transfer time should be retained within their assigned project. The minimum late finish activity scheduling rule is also shown to perform better than the minimum slack activity scheduling rule.
Manufacturing strategy and production systems: An integrated framework
Authors: Kim Yearnmin , Lee Jinjoo
Published: October 2002

This paper suggests a set of potential profiles for different types of production systems and manufacturing strategies and deals with the contingency framework that links production systems to manufacturing strategies. Specifically, an explicit conceptual link is drawn between “generic manufacturing strategy” that uses two dimensions of strategy (cost efficiency and differentiation) and the complementary production system typology in manufacturing that uses technical complexity and technical flexibility. Proposed production systems are “intermittent production system”, “continuous production system”, “concurrent production system”, and “degenerate production system”. This paper also expands the area of interest to focus on the development of methods and measures of each technology dimension that can be validated in some way.

Thus, this study, by suggesting an integrated framework, clarifies and combines the terms and concepts related to manufacturing strategies based on the results of business strategy research and new manufacturing technology for further empirical study with this framework.
The impact of lot splitting on due date performance
Authors: Wagner Bret J. , Ragatz Gary L.
Published: October 2002

The primary purpose of the research project was to determine if the flow time reductions that occur from splitting jobs into smaller transfer batches result in improved due data performance. The research was performed using a computer simulation of a five machine open job shop. In the open shop environment, each job is unique, and the flow time reductions are solely a result of overlapping operations rather than saved setups from processing similar jobs in sequence. To determine the impact of lot splitting on due date performance, two questions had to be answered. First, how does the impact of lot splitting vary with the magnitude of setup times? Second, how does the size of the transfer batch affect lot splitting performance?

This study shows the benefits from lot splitting improve monotonically with decreasing transfer batch size and that lot splitting provides improvements that are essentially independent of the setup time as long as the total utilization (ratio of setup and processing time to available time) is constant. As for the primary research question, lot splitting can provide substantial reductions in mean tardiness (up to 39%) and number of jobs tardy in the open shop environment.

The repetitive lots logic developed by Jacobs and Bragg (1988) is reformulated to clearly show that it can be used in combination with any dispatching rule. This rule demonstrates that the repetitive lots logic makes surprisingly good scheduling decisions in spite of its simplicity.

Lot splitting is shown to be a simple and effective means of improving the performance of an open job shop. Based on its robust performance in this study, the benefits should be able to be realized in combination with other shop floor control techniques, such as order review release and order expediting.
Masthead Vol.2 No.1
Authors: Mandell Lewis
Published: October 2002

NA
From the Editor Vol 2 No 1
Authors: Mandell Lewis
Published: October 2002

NA
Nobody Gains from Dollar Cost Averaging Analytical, Numerical and Empirical Results
Authors: Knight John R. , Mandell Lewis
Published: October 2002

Dollar Cost Avemging is an investment system that is widely advocated by brokerage firms and mutual funds. In its best known form, an investor seeking to put a lump sum into risky assets is counseled to invest the money over a period of time in equal installments in or&r to avoid the devastating effect of a marketfall immediately afkr a single, lump-sum investment. Using graphical analysis, historical stock market returns, and Monte Carlo simulations, this article demonstmtes that no such benefit accrues to a Dollar Cost Averaging Stmtegy. Two alternative strategies, optimal rebalancing and buy and hold achieve better performance in all three analyses.
Temporal and spatial expression of two isoforms of the Dutt1/Robo1 gene in mouse development
Authors: Clark Katherine , Hammond Ester , Rabbitts Pamela
Published: October 2002

The mammalian homologue of the Drosophila axonal guidance receptor roundabout is expressed in a wide range of tissues. Here we show that alternative splicing of the Dutt1/Robo1 gene results in two mRNA transcripts with different signal peptides, which are differentially expressed throughout mouse embryogenesis. Since mice with a targeted deletion in the Dutt1/Robo1 gene have abnormal lung pathology, immunohistochemistry was used to identify the cellular expression pattern of Dutt1/Robo1 during lung development. Dutt1/Robo1 expression was widespread and diffuse in the lung at embryonic day 17.5 but became increasingly localised to the bronchial epithelium in newborn and adult mice.
Structural domains required for channel function of the mouse transient receptor potential protein homologue TRP1β
Authors: Engelke Michael , Friedrich Olaf , Budde Petra , Schäfer Christina , Niemann Ursula , Zitt Christof , Jüngling Eberhard , Rocks Oliver , Lückhoff Andreas , Frey Jürgen
Published: October 2002

Transient receptor potential proteins (TRP) are supposed to participate in the formation of store‐operated Ca2+ influx channels by co‐assembly. However, little is known which domains facilitate the interaction of subunits. Contribution of the N‐terminal coiled‐coil domain and ankyrin‐like repeats and the putative pore region of the mouse TRP1β (mTRP1β) variant to the formation of functional cation channels were analyzed following overexpression in HEK293 (human embryonic kidney) cells. MTRP1β expressing cells exhibited enhanced Ca2+ influx and enhanced whole‐cell membrane currents compared to mTRP1β deletion mutants. Using a yeast two‐hybrid assay only the coiled‐coil domain facilitated homodimerization of the N‐terminus. These results suggest that the N‐terminus of mTRP1β is required for structural organization thus forming functional channels.
Cloning and characterization of two novel aldo‐keto reductases (AKR1C12 and AKR1C13) from mouse stomach
Authors: Ikeda Sakahiro , Okuda-Ashitaka Emiko , Masu Yasuo , Suzuki Toshiko , Watanabe Kikuko , Nakao Masafumi , Shingu Koh , Ito Seiji
Published: October 2002

In contrast to hepatic hydrosteroid dehydrogenases (HSDs) of the aldo‐keto reductase family (AKR1C), little is known about a stomach one. From a mouse stomach cDNA library, we isolated two clones encoding proteins of 323 amino acid residues. They exhibited 93.2% amino acid sequence identity and 64–68% with any known HSDs. Recombinant proteins expressed in Escherichia coli reduced 9,10‐phenanthraquinone with NAD(P)H as cofactor. The mRNAs were exclusively expressed in stomach, liver and ileum. The present study demonstrates that these proteins are new members of the HSD subfamily and they are named AKR1C12 and AKR1C13. Immunohistochemical analysis suggests that they are involved in detoxification of xenobiotics in the stomach.
From supply to demand chain management: efficiency and customer satisfaction
Authors: Heikkilä Jussi
Published: October 2002

How do companies in the fast‐growing industries achieve good customer satisfaction together with efficiency in supply chain management (SCM)? This inductive case study of six customer cases of Nokia Networks, one of the leading providers of mobile telecommunication technology, led to propositions exploring that question. Good relationship between the customer and the supplier contributes to reliable information flows, and reliable demand information flows in turn contribute to high efficiency—these are well‐researched issues also in other industry environments. But in a fast‐growing systems business such as mobile telecommunications industry, the supplier needs to be able to adapt its offering to a wide variety of customer situations and needs. Understanding the customer’s situation and need together with the right offering contributes to good co‐operation in improving the joint demand chain, which further leads to superior demand chain efficiency and high customer satisfaction.
Retail stocking decisions with order and stock sales
Authors: Rajagopalan S. , Kumar K.Ravi
Published: October 2002

Key factors for success in competitive markets are to be able to offer the customer the product features he/she desires and still maintain low costs. We believe that, just as lean manufacturing has helped reduce inventories in factories, there is a need for lean retailing to reduce the large inventories at retailers. One way to do this is to exploit the potential for order‐and‐wait sales rather than hold a lot of inventory, especially in high‐variety environments. This paper analyzes retailing operations from this perspective and looks at the issue of providing the customer with the option of purchasing from stock or by placing an order, when variety is an inherent feature of the product market. A multi‐period, multiproduct model with a constraint on the amount of stock that can be held is developed, with both stock and order‐and‐wait sales possible. We provide an optimal procedure to solve the problem and develop other key results. First, we show that the optimal quantity of stock to be held by the retailer decreases when the option of placing an order is offered. The idea is that, through identifying and servicing segments of consumers with a propensity to waiting, retailers can reduce their stocking levels (and costs) needed to service those consumers who have no desire to wait for product delivery. Another key conclusion is that, in some contexts, the retailer should actually be offering discounts to those who will place an order and wait for the product they desire. However, under certain conditions, it may indeed be optimal to charge a premium for the ordered item (relative to in‐stock items).
Homicide by schizophrenic patients in Israel
Authors: Valevski A. , Averbuch I. , Radwan M. , Gur S. , Spivak B. , Modai I. , Weizman A.
Published: October 2002

Thirty-three schizophrenic inpatients aged 45.3 ± 13.5 years who had been found not guilty of homicide by reason of insanity were compared with 28 schizophrenic patients matched for age, sex and duration of disease who had not committed any crime. Statistical analysis revealed a high rate in the study group of individual factors associated with aggression, such as alcohol abuse, previous contact with the police, aggressive behavior and threats (P < 0.05). Significantly more of them were also immigrants (P < 0.05). There was no between-group difference in familial factors. These findings support earlier studies indicating that schizophrenic patients with the profile of alcoholism, aggressiveness and foreign country of origin are at high risk of homicidal behavior.
Myocardial contractile reserve under low doses of dobutamine and improvement of left ventricular ejection fraction with treatment by carvedilol
Authors: Jourdain P. , Funck F. , Fulla Y. , Hagege A. , Bellorini M. , Guillard N. , Loiret J. , Thebault B. , Desnos M.
Published: October 2002

To examine the ability of myocardial contractile reserve (MCR) assessment to predict the improvement of left ventricular ejection fraction with treatment by carvedilol, a prospective study was undertaken in 85 patients with chronic heart failure and left ventricular ejection fraction <45%. Low dose dobutamine echocardiography (DSE), a 6‐min walk test and measured brain natriuretic peptide (BNP) were assessed in all the patients. Patients were separated into two groups. Group A were patients without any myocardial reserve and group B patients with a myocardial contractile reserve defined as an increment of more than 20% of the resting left ventricular ejection fraction during dobutamine infusion. The two groups differed for percentage of ischemic cardiomyopathy (67.8 in group A vs. 29.7% in group B P‐0.028), 6‐min walk test performance (respectively, 343 vs. 415 meters P<0.05) and BNP plasma levels (respectively, 184.5 vs. 70.1 P<0.02) but not for left ventricular ejection fraction or NYHA class. During DSE, MCR and heart rate variation was higher in group B than in group A. At the end of the follow up, LVEF increased and NYHA class decreased in group B but not in group A. In multivariate analysis the existence of MCR could predict the improvement of LVEF with treatment by carvedilol. In our study, studying MCR could help to predict patients who will improve their LVEF with carvedilol prior to the administration of the treatment.
Role of trapped and circulating particles in
inducing current drive and radial electric field
by Alfvén waves in tokamaks
Authors: TSYPIN V. S. , GALVÃO R. M. O. , NASCIMENTO I. C. , TENDLER M. , SEVERO J. H. F. , RUCHKO L. F.
Published: October 2002

Absorption by trapped particles is supposed to seriously hinder current
drive by Alfvén waves. However, it is shown in this paper that the same effect is
rather beneficial for the emergence of the radial electric field induced by these waves,
which is important for creating and maintaining transport barriers in tokamaks.
Occurrence of ocean sunfish, Mola mola near fronts in the western English Channel
Authors: Sims D.W. , Southall E.J.
Published: October 2002

Surface occurrence of ocean sunfish (Mola mola) was recorded during summer (May–September) in the western English Channel off Plymouth over a six-year period between 1995 and 2001. Fifteen individuals of between 0.5–0.7 m estimated total length were sighted during 1651 hours of observation. Nearly all sightings (93%) occurred in June and July in water between 13 and 17°C. Sunfish were mostly associated with frontal and stratified water masses (86%) rather than in cooler, mixed water.
Acute hospitals and older people in Australia
Authors: MCCORMACK JOHN
Published: October 2002

The Australian health care system is frequently portrayed as being in crisis, with reference to either large financial burdens in the form of hospital deficits, or declining service levels. Older people, characterised as a homogeneous category, are repeatedly identified as a major contributor to the crisis, by unnecessarily occupying acute beds while they await a vacancy in a residential facility. Several enquiries and hospital taskforce management groups have been set up to tackle the problem. This article reviews their findings and strategic recommendations, particularly as they relate to older people. Short-term policy responses are being developed which specifically target older people for early discharge and alternative levels of care, and which, while claiming positive intentions, may introduce new forms of age discrimination into the health system. Few of the currently favoured proposals promote age-inclusivity and older people's rights to equal access to acute care.
Shifting serotypes, plasmid profile analysis and antimicrobial resistance pattern of shigellae strains isolated from Kolkata, India during 1995–2000
Authors: DUTTA S. , RAJENDRAN K. , ROY S. , CHATTERJEE A. , DUTTA P. , NAIR G. B. , BHATTACHARYA S. K. , YOSHIDA S-I.
Published: October 2002

One hundred and sixty-six shigellae strains, isolated from stool samples of paediatric patients (<5 years old) at a Childrens' Hospital in Kolkata, India during the period of 1995–2000 were examined for serotyping, drug resistance pattern and plasmid profiles. Sh. flexneri (58%) was found to be commonest isolate of total shigellae, followed by Sh. sonnei (28%), Sh. boydii (9%) and Sh. dysenteriae (5%). This profile of species was in sharp contrast to the picture obtained before 1995, when Sh. dysenteriae 1 predominated over Sh. flexneri. In Sh. flexneri strains, Sh. flexneri 2a (35%) was the most prevalent serotype, following Sh. flexneri 3a (31%), Sh. flexneri 6 (14%), Sh. flexneri 2b (11%) and Sh. flexneri 4 (9%). Resistance patterns of the strains to 12 commonly used antimicrobial agents and minimum inhibitory concentrations (MICs) of the antibiotics were also tested. All strains were found uniformly susceptible to norfloxacin, but more than 90% strains were resistant to tetracycline, co-trimoxazole and 67% strains were resistant to ampicillin. Resistance to amoxicillin, chloramphenicol and nalidixic acid was found in 55% (range 45–74%), 46% (range 40–60%) and 29% (range 15–40%) strains respectively. Overall, shigellae strains showed statistically significant increase in resistance against tetracycline, nalidixic acid and furazolidone (P<0.05) over the years of this study. This indicates decreased efficacy of furazolidone, cotrimoxazole and nalidixic acid for the empirical treatment of shigellosis in Kolkata. Although a few strains showed intermediate susceptibility to ciprofloxacin (4%) and cefotaxime (10%) by disk diffusion test, but the MICs of those antibiotics were within the normal limits. Almost 57% of the strains were resistant to four or more drugs with high MICs of the antibiotics. Plasmid profile analysis revealed presence of large plasmid of 220 kb in majority of the strains except in Sh. sonnei and a correlation between presence of smaller plasmids and shigellae serotypes. Hence this study reports epidemiological change of shigellae species in Kolkata, India with regard to serotypes and antibiotic resistance patterns.
The use of sequential studies in a salmonellosis outbreak linked to continental custard cakes
Authors: WARD B. , ANDREWS R. , GREGORY J. , LIGHTFOOT D.
Published: October 2002

We investigated an outbreak of 54 cases of Salmonella Typhimurium phage type 9 (STM9) with a specific antibiotic resistance pattern. We used sequential analytic studies: two retrospective cohort studies, a case-control study, and a modified case-control study. An outbreak of salmonellosis due to Salmonella Typhimurium PT9 SSu (resistant to streptomycin and sulphafurazole) was identified. Fifty-four cases had illness onset from November 1998 to March 1999. Notifications commenced following a restaurant birthday party in December 1998. An initial cohort and case control study found no association with consumption of custard cake. However, case follow-up identified another cohort of people who had attended a birthday party in February at which 8/27 people who consumed a continental custard cake were ill compared to 0/10 who did not (P = 0.07). A revised case control study found illness was strongly associated with consumption of a particular continental custard cake (Mantel–Haenszel matched OR ∞, P = 0.00004). This report highlights the epidemiological value of using sequential study types, and persisting with the investigation of apparently sporadic food-borne outbreaks.
Investigation of an outbreak of cercarial dermatitis
Authors: LÉVESQUE B. , GIOVENAZZO P. , GUERRIER P. , LAVERDIÈRE D. , PRUD'HOMME H.
Published: October 2002

We present the investigation of an outbreak of cercarial dermatitis that occurred in a recreational-tourist lake in the Québec City region (Canada) in the summer of 1999. A case-reporting form was sent to 450 families likely to have activities that would bring them in contact with the lake's water. The snails were characterized and the prevalence of their infestation by schistosomes was investigated. In total, 63 episodes consistent with cercarial dermatitis were reported. Sixty-nine percent of the cases occurred from swimming at the same beach. This location was the one where the only population of snails in the lake was identified. Shoreline residents were informed that they should not feed waterfowl, and a clean-up of the snail population was done at the start of the following summer. There were no cases of cercarial dermatitis at this site the following summer.
Phylogenetic and antigenic analysis of influenza A(H3N2) viruses isolated from conscripts receiving influenza vaccine prior to the epidemic season of 1998/9
Authors: PYHÄLÄ R. , IKONEN N. , HAANPÄÄ M. , SANTANEN R. , TERVAHAUTA R.
Published: October 2002

Roughly half (54%) of the 910 young conscripts at a garrison in Finland were vaccinated with commercial influenza vaccines in autumn 1998. During the influenza outbreak in February 1999, 12 H3N2-subtype virus strains were isolated from vaccinated patients, and 11 such strains were isolated from unvaccinated patients. The isolates were related to the vaccine strain A/Sydney/5/97 and could be classified into three subgroups based on sequence variation in the HA1 gene coding for the variable domain of viral haemagglutinin (HA). A total of 6–10 amino-acid substitutions in HA1, three of these in the receptor-binding site, differentiated the field strains from the vaccine virus. In haemagglutination inhibition (HI) tests, eight strains from the study population exhibited reduced reactivity with a variety of antisera including human post-vaccination sera. Six of these strains were isolated from vaccinated and two from unvaccinated patients. The reduced reactivity did not correlate with particular amino-acid changes in HA1. We suggest that low-reactivity viruses may have an advantage over other co-circulating variants under some circumstances characterized by enhanced immunity-mediated selection and high infection pressure. Whether the frequency of these viruses increased in our vaccinated study population cannot be determined, nor can their effect on vaccine efficacy.
Variable ambisyllabicity
Authors: Trousdale Graeme
Published: October 2002

This article is an attempt to account for data, collected from twenty speakers of Tyneside English (TE), which seem to indicate that syllabification of the oral stops in certain positions in English is subject to dialectal variation, and that the issue of syllabification is closely linked to patterns of glottal reinforcement and glottal substitution in the TE variety. Models of syllable structure based on data from ‘standard’ accents such as Received Pronunciation (RP) therefore fail to account for patterns in nonstandard varieties. In what follows, I propose some revisions to the RP-based account provided in Giegerich (1999) which are necessary to account for the TE data and, furthermore, I emphasize the need for a more holistic approach to studies of variation, which attempts to synthesize structural and sociolinguistic principles.
Chemical Inactivation of the Cinnamate 4-Hydroxylase Allows for the Accumulation of Salicylic Acid in Elicited Cells
Authors: Schoch Guillaume A. , Nikov Georgi N. , Alworth William L. , Werck-Reichhart Danièle
Published: October 2002

The cinnamate (CA) 4-hydroxylase (C4H) is a cytochrome P450 that catalyzes the second step of the main phenylpropanoid pathway, leading to the synthesis of lignin, pigments, and many defense molecules. Salicylic acid (SA) is an essential trigger of plant disease resistance. Some plant species can synthesize SA from CA by a mechanism not yet understood. A set of specific inhibitors of the C4H, including competitive, tight-binding, mechanism-based irreversible, and quasi-irreversible inhibitors have been developed with the main objective to redirect cinnamic acid to the synthesis of SA. Competitive inhibitors such as 2-hydroxy-1-naphthoic acid and the heme-coordinating compound 3-(4-pyridyl)-acrylic acid allowed strong inhibition of C4H activity in a tobacco (Nicotiana tabacum cv Bright Yellow [BY]) cell suspension culture. This inhibition was however rapidly relieved either because of substrate accumulation or because of inhibitor metabolism. Substrate analogs bearing a methylenedioxo function such as piperonylic acid (PIP) or a terminal acetylene such as 4-propynyloxybenzoic acid (4PB), 3-propynyloxybenzoic acid, and 4-propynyloxymethylbenzoic acid are potent mechanism-based inactivators of the C4H. PIP and 4PB, the best inactivators in vitro, were also efficient inhibitors of the enzyme in BY cells. Inhibition was not reversed 46 h after cell treatment. Cotreatment of BY cells with the fungal elicitor β-megaspermin and PIP or 4PB led to a dramatic increase in SA accumulation. PIP and 4PB do not trigger SA accumulation in nonelicited cells in which the SA biosynthetic pathway is not activated. Mechanism-based C4H inactivators, thus, are promising tools for the elucidation of the CA-derived SA biosynthetic pathway and for the potentiation of plant defense.
l-Ascorbic Acid Is Accumulated in Source Leaf Phloem and Transported to Sink Tissues in Plants
Authors: Franceschi Vincent R. , Tarlyn Nathan M.
Published: October 2002

l-Ascorbic acid (AsA) was found to be loaded into phloem of source leaves and transported to sink tissues. Whenl-[14C]AsA was applied to leaves of intact plants of three different species, autoradiographs and HPLC analysis demonstrated that AsA was accumulated into phloem and transported to root tips, shoots, and floral organs, but not to mature leaves. AsA was also directly detected in Arabidopsis sieve tube sap collected from an English green aphid (Sitobion avenae) stylet. Feeding a single leaf of intact Arabidopsis or Medicago sativawith 10 or 20 mm  l-galactono-1,4-lactone (GAL-l), the immediate precursor of AsA, lead to a 7- to 8-fold increase in AsA in the treated leaf and a 2- to 3-fold increase of AsA in untreated sink tissues of the same plant. The amount of AsA produced in treated leaves and accumulated in sink tissues was proportional to the amount of GAL-l applied. Studies of the ability of organs to produce AsA from GAL-l showed mature leaves have a 3- to 10-fold higher biosynthetic capacity and much lower AsA turnover rate than sink tissues. The results indicate AsA transporters reside in the phloem, and that AsA translocation is likely required to meet AsA demands of rapidly growing non-photosynthetic tissues. This study also demonstrates that source leaf AsA biosynthesis is limited by substrate availability rather than biosynthetic capacity, and sink AsA levels may be limited to some extent by source production. Phloem translocation of AsA may be one factor regulating sink development because AsA is critical to cell division/growth.