bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of direction of rotation in continuous and discontinuous 8 hour shift systems
Authors: Tucker Philip , Smith Lawrence , Macdonald Ian , Folkard Simon 
Published: July 2002

OBJECTIVESPrevious research has produced conflicting evidence on the relative merits of advancing and delaying shift systems. The current study assessed the effects of the direction of shift rotation within 8 hour systems, upon a range of measures including sleep, on shift alertness, physical health, and psychological wellbeing.METHODSAn abridged version of the standard shiftwork index which included retrospective alertness ratings was completed by four groups of industrial shiftworkers on relatively rapidly rotating 8 hour systems (n=611). Two groups worked continuous systems that were either advancing or delaying; the other two groups worked discontinuous systems that were either advancing or delaying.RESULTSFew effects were found of direction of rotation on chronic measures of health and wellbeing, even when the systems incorporated “quick returns” (a break of only 8 hours when changing from one shift to another). This was despite the use of measures previously shown to be sensitive to the effects of a broad range of features of shift systems. However, advancing continuous systems seemed to be associated with marginally steeper declines in alertness across the shift (F(3,1080)=2.87, p<0.05). They were also associated with shorter sleeps between morning shifts (F(1,404)=4.01, p<0.05), but longer sleeps between afternoons (F(1,424)=4.16, p<0.05).CONCLUSIONSThe absence of negative effects of advancing shifts upon the chronic outcome measures accorded with previous evidence that advancing shifts may not be as harmful as early research indicated. However, this interpretation is tempered by the possibility that difficult shift systems self select those workers most able to cope with their deleterious effects. The presence of quick returns in advancing continuous systems seemed to impact upon some of the acute measures such as duration of sleep, although the associated effects on alertness seemed to be marginal.
Increased nitric oxide in exhaled air: an early marker of asthma in non-smoking aluminium potroom workers?
Authors: Lund M B , Øksne P I , Hamre R , Kongerud J 
Published: July 2002

OBJECTIVESTo study exhaled nitric oxide (NO) as a marker of airway inflammation caused by potroom exposure, hypothesising that (a) workers exposed to potroom pollutants would have higher concentrations of NO in expired air than control subjects employed at the same plant but working outside of the potroom atmosphere, and (b) that concentrations of exhaled NO in potroom employees might be positively associated with concentrations of fluoride and exposure to dust.METHODSA study group comprising 186 male subjects (aged 24–63 years), employed in the potrooms of one Norwegian aluminium smelter, and 40 comparable control subjects (aged 25–60 years) recruited from the same plant, were examined by measurements of exhaled and nasal concentrations of NO, spirometry, and a questionnaire on respiratory symptoms as a part of an annual health surveillance programme. Estimates of exposure to fluorides and dust for selected job categories were obtained by means of personal samplers carried by the workers.RESULTSIn the non-smokers, the concentrations of exhaled NO were higher in the potroom workers than in the controls (median (interquartile range) 9.3 (6.2–15.6)v5.7 (4.6–8.3) ppb, p=0.001). The two groups did not differ in spirometry and asthma-like symptoms. Non-smoking potroom workers with asthma-like symptoms had higher concentrations of exhaled NO than those with no symptoms (median (interquartile range) 21.0 (19.3–41.4)v8.5 (5.9–12.8) ppb, p=0.001), but had comparable spirometric values. In subjects who smoked, the concentrations of exhaled NO did not differ significantly between potroom workers and controls (median (interquartile range) 4.6 (3.3–8.0)v4.0 (3.4–5.1) ppb. Exhaled NO was not significantly associated with either duration of employment or routine measurements of dust and fluorides.CONCLUSIONSExposure to potroom pollutants is associated with increased concentrations of exhaled NO in non-smoking subjects. Nitric oxide in exhaled air may be an early marker of airway inflammation in aluminium potroom workers.
Short term influence of mechanical factors on regional musculoskeletal pain: a study of new workers from 12 occupational groups
Authors: Nahit E S , Macfarlane G J , Pritchard C M , Cherry N M , Silman A J 
Published: July 2002

OBJECTIVESTo determine the influence of short term exposure to mechanical factors on regional musculoskeletal pain.METHODSFull time newly employed workers were recruited from 12 occupational groups and information collected by questionnaire. Subjects indicated on a blank body manikin any low back, shoulder, wrist or forearm or both, or knee pain which had occurred during the past month and had lasted more than 1 day. Data were also collected with a previously validated questionnaire on working postures, manual handling activities, and repetitive movements of the upper limb. The relations between mechanical factors and each area of pain were calculated as odds ratios (ORs) with 95% confidence intervals (95% CIs). Adjustment was made for age and sex.RESULTS1081 subjects (median age 23; interquartile range 20–27) were recruited to the study (a participation rate of 91%). 261 (24%) reported low back pain, 221 (20%) shoulder pain, 93 (9%) wrist or forearm pain, and 222 (21%) knee pain. Several specific manual handling activities were found to be associated with low back, shoulder, and knee pain. Carrying weights of more than 50 lbs (23 kg) on one shoulder was the factor which was most strongly associated with low back pain (OR 2.4 (95% CI 1.5 to 3.8)), shoulder pain (OR 3.1 (95% CI 1.9 to 4.8)), and knee pain (OR 3.5 (95% CI 2.2 to 5.5)), whereas forearm pain was most strongly associated with repetitive movements of the wrists (OR 1.8 (95% CI 1.04 to 3.1)). By contrast very few postures were associated with regional pain, although bending forwards in an uncomfortable position for at least 15 minutes was associated with shoulder pain (OR 1.6 (95% CI 1.2 to 2.2)) and kneeling for at least 15 minutes was associated with knee pain (OR 1.8 (95% CI 1.2 to 2.6)). Exposure to mechanical factors was most strongly associated with pain at multiple sites rather than with pains in individual regions.CONCLUSIONSEven among workers with only short term exposure to mechanical factors, musculoskeletal pain is increased.
Use of routinely collected data on trihalomethane in drinking water for epidemiological purposes
Authors: Keegan T , Whitaker H , Nieuwenhuijsen M J , Toledano M B , Elliott P , Fawell J , Wilkinson M , Best N 
Published: July 2002

OBJECTIVESTo explore the use of routinely collected trihalomethane (THM) measurements for epidemiological studies. Recently there has been interest in the relation between byproducts of disinfection of public drinking water and certain adverse reproductive outcomes, including stillbirth, congenital malformations, and low birth weight.METHODFive years of THM readings (1992–6), collected for compliance with statutory limits, were analysed. One water company in the north west of England, divided into 288 water zones, provided 15 984 observations for statistical analysis. On average each zone was sampled 11.1 times a year. Five year, annual, monthly, and seasonal variation in THMs were examined as well as the variability within and between zones.RESULTSBetween 1992 and 1996 the total THM (TTHM) annual zone means were less than half the statutory concentration, at approximately 46 μg/l. Differences in annual water zone means were within 7%. Over the study period, the maximum water zone mean fell from 142.2 to 88.1 μg/l. Mean annual concentrations for individual THMs (μg/l) were 36.6, 8.0, and 2.8 for chloroform, bromodichloromethane (BDCM), and dibromochloromethane (DBCM) respectively. Bromoform data were not analysed, because a high proportion of the data were below the detection limit. The correlation between chloroform and TTHM was 0.98, between BDCM and TTHM 0.62, and between DBCM and TTHM −0.09. Between zone variation was larger than within zone variation for chloroform and BDCM, but not for DBCM. There was only little seasonal variation (<3%). Monthly variation was found although there were no consistent trends within years.CONCLUSIONIn an area where the TTHM concentrations were less than half the statutory limit (48 μg/l) chloroform formed a high proportion of TTHM. The results of the correlation analysis suggest that TTHM concentrations provided a good indication of chloroform concentrations, a reasonable indication of BDCM concentrations, but no indication of DBCM. Zone means were similar over the years, but the maximum concentrations reduced considerably, which suggests that successful improvements in treatment have been made to reduce high TTHM concentrations in the area. For chloroform and BDCM, the main THMs, the component between water zones was greater than variation within water zones and explained most of the overall exposure variation. Variation between months and seasons was low and showed no clear trends within years. The results indicate that routinely collected data can be used to obtain exposure estimates for epidemiological studies at a small area level.
The role of penile prosthetic surgery in the modern management of erectile dysfunction
Authors: Jain S , Bhojwani A , Terry T R 
Published: July 2002

Summary
The management of erectile dysfunction looks set to be revolutionised with the introduction of effective oral therapies. There will remain, however, some men who do not respond to conservative measures. This article reviews the important role of penile prosthetic surgery as a treatment option in these patients.
Calciphylaxis
Authors: Mathur R V , Shortland J R , El Nahas A M 
Published: July 2002

Abstract
The phenomenon of calciphylaxis is rare, but potentially fatal. It has been recognised for a long time in patients with chronic renal failure with secondary hyperparathyroidism. Disturbed calcium and phosphate metabolism can result in painful necrosis of skin, subcutaneous tissue and acral gangrene. Appearance of the lesions is distinctive but the pathogenesis remains uncertain. The beneficial effects of parathyroidectomy are controversial. However, correction of hyperphosphataemia or occasionally hypercalcaemia is imperative. Fulminant sepsis as a consequence of secondary infection of necrotic and gangrenous tissue is a frequent cause of patient morbidity and mortality.
Effect of clean indoor air laws on smokers: the clean air module of theSimSmokecomputer simulation model
Authors: Levy David T , Friend Karen , Polishchuk Eugene 
Published: July 2002

OBJECTIVESTo develop a simulation model to examine the effects of clean indoor air laws on prevalence rates and smoking attributable deaths.METHODSBased on empirical and theoretical research, the effects of clean air laws are modelled by type of law. The model considers clean air laws at the state levels between 1993 and 2000, and projects the number of smokers and smoking attributable deaths in the USA under different scenarios from 2000 onward.RESULTSThe model predicts that comprehensive clean air laws have the potential to reduce substantially the number of smokers and smoking attributable deaths, and these effects are predicted to grow over time. The predicted impact of new worksite laws are reduced when previously implemented private and public worksite restrictions are taken into account.CONCLUSIONSClean indoor air laws have the ability to reduce smoking rates substantially and save lives, but their impact is likely to depend on their comprehensiveness and prior private worksite restrictions in place.
CLARIFYING CHAOS III: CHAOTIC AND STOCHASTIC PROCESSES, CHAOTIC RESONANCE, AND NUMBER THEORY
Authors: BROWN RAY , CHUA LEON O. 
Published: July 2002

In this tutorial we continue our program of clarifying chaos by examining the relationship between chaotic and stochastic processes. To do this, we construct chaotic analogs of stochastic processes, stochastic differential equations, and discuss estimation and prediction models. The conclusion of this section is that from the composition of simple nonlinear periodic dynamical systems arise chaotic dynamical systems, and from the time-series of chaotic solutions of finite-difference and differential equations are formed chaotic processes, the analogs of stochastic processes. Chaotic processes are formed from chaotic dynamical systems in at least two ways. One is by the superposition of a large class of chaotic time-series. The second is through the compression of the time-scale of a chaotic time-series. As stochastic processes that arise from uniform random variables are not constructable, and chaotic processes are constructable, we conclude that chaotic processes are primary and that stochastic processes are idealizations of chaotic processes. Also, we begin to explore the relationship between the prime numbers and the possible role they may play in the formation of chaos.
CLOSED SUBGROUPS IN PRO-V TOPOLOGIES AND THE EXTENSION PROBLEM FOR INVERSE AUTOMATA
Authors: MARGOLIS S. , SAPIR M. , WEIL P. 
Published: July 2002

We relate the problem of computing the closure of a finitely generated subgroup of the free group in the pro-V topology, where V is a pseudovariety of finite groups, with an extension problem for inverse automata which can be stated as follows: given partial one-to-one maps on a finite set, can they be extended into permutations generating a group in V? The two problems are equivalent when V is extension-closed. Turning to practical computations, we modify Ribes and Zalesskiĭ's algorithm to compute the pro-p closure of a finitely generated subgroup of the free group in polynomial time, and to effectively compute its pro-nilpotent closure. Finally, we apply our results to a problem in finite monoid theory, the membership problem in pseudovarieties of inverse monoids which are Mal'cev products of semilattices and a pseudovariety of groups. Résumé: Nous établissons un lien entre le problème du calcul de l'adhéerence d'un sous-groupe finiment engendré du groupe libre dans la topologie pro-V, oú V est une pseudovariété de groupes finis, et un probléme d'extension pour les automates inversifs qui peut être énoncé de la faç con suivante: étant données des transformations partielles injectives d'un ensemble fini, peuvent-elles être étendues en des permutations qui engendrent un groupe dans V? Les deux problèmes sont équivalents si V est fermée par extensions. Nous intéressant ensuite aux calculs pratiques, nous modifions l'algorithme de Ribes et Zalesskiĭ pour calculer l'adhérence pro-p d'un sous-groupe finiment engendré du groupe libre en temps polynomial et pour calculer effectivement sa clôture pro-nilpotente. Enfin nous appliquons nos résultats à un problème de théorie des monoïdes finis, celui de de l'appartenance dans les pseudovariétés de monoïdes inversifs qui sont des produits de Mal'cev de demi-treillis et d'une pseudovariété de groupes.
MODEL STUDY OF FACTORS INFLUENCING STEADY STATE CLEARANCE FOR LIPOPHILIC TOXICANTS IN AQUATIC MICROCOSMS
Authors: VENTURINO ANDRÉS , ROVEDATTI MARÍA GABRIELA , GAUNA LIDIA , LOEWY MIRIAM , DE D'ANGELO ANA MARÍA PECHEN 
Published: July 2002

We have studied the distribution and bioelimination of the organophosphorus pesticide parathion in a native microcosm consisting of water, sediment, bivalves and aquatic plants. A common apparent clearance constant for biotic and abiotic components was suggested from the analysis of parathion accumulation and degradation. In this work we developed a global model explaining the toxicokinetics of a lipophilic compound and particurlarly the common steady state degradation in an aquatic microcosm, using a set of linear differential equations. We simulated the distribution and degradation of the compound in the microcosm, and fitted single-compartment equation models to data, estimating the apparent sorption and elimination constants. We verified the existence of a common apparent degradation constant for all the compartments. We infer from the mathematical expressions and corroborate from the simulated data that the apparent degradation constant is equal to the sum of the metabolization rates at each biotic compartment multiplied by the compound mass ratios established at steady state between the biotic and the abiotic compartments. Product kinetics simulation showed that steady state might also be achieved in the different compartments, with the same apparent constant as that obtained for toxicant clearance. As a practical result, the total radioactivity in water would serve to calculate the global clearance constant in a simple experimental way if a radiotracer is used. Physical and chemical degradation and chemical loss due to volatilization and CO 2 diffusion were analyzed in the microcosm model. The assessments of the cases where these factors affect the clearance process as well as the implications emerged are discussed.
DEADLINE ALLOCATION IN A TIME-CONSTRAINED WORKFLOW
Authors: SON JIN HYUN , KIM JUNG HOON , KIM MYOUNG HO 
Published: July 2002

Workflow management systems should efficiently manage workflow constraints such as time, resource, and cost during workflow executions. Especially, workflow time management is important in timely scheduling of workflow process execution, avoiding deadline violations, and improving the workflow throughput. Though there have been some studies on the dynamic deadline management in a workflow, the importance of the static deadline management has not been much addressed in the past. We first describe our workflow model considered in this paper. Then, we propose a static deadline allocation method that can facilitate an efficient workflow processing. The proposed method can achieve high workflow throughput by analyzing the interrelated workflow components. We also present various experimental results that show the usefulness and efficiency of the method.
Cooperative shared memory
Authors: Hill Mark D. , Larus James R. , Reinhardt Steven K. , Wood David A. 
Published: July 2002

We believe the paucity of massively parallel, shared-memory machines follows from the lack of a shared-memory programming performance model that can inform programmers of the cost of operations (so they can avoid expensive ones) and can tell hardware designers which cases are common (so they can build simple hardware to optimize them). Cooperative shared memory, our approach to shared-memory design, addresses this problem.Our initial implementation of cooperative shared memory uses a simple programming model, called Check-In/Check-Out (CICO), in conjunction with even simpler hardware, called Dir1SW. In CICO, programs bracket uses of shared data with a check_in directive terminating the expected use of the data. A cooperative prefetch directive helps hide communication latency. Dir1SW is a minimal directory protocol that adds little complexity to message-passing hardware, but efficiently supports programs written within the CICO model.
Formal aspects of concurrency control in long-duration transaction systems using the NT/PV model
Authors: Korth Henry F. , Speegle Greg 
Published: July 2002

In the typical database system, an execution is correct if it is equivalent to some serial execution. This criterion, called serializability, is unacceptable for new database applications which require long-duration transactions. We present a new transaction model which allows correctness criteria more suitable for these applications. This model combines three enhancements to the standard model: nested transactions, explicit predicates, and multiple versions. These features yield the name of the new model, nested transactions with predicates and versions, or NT/PV.
The modular nature of the NT/PV model allows a straightforward representation of simple systems. It also provides a formal framework for describing complex interactions. The most complex interactions the model allows can be captured by a protocol which exploits all of the semantics available to the NT/PV model. An example of these interactions is shown in a CASE application. The example shows how a system based on the NT/PV model is superior to both standard database techniques and unrestricted systems in both correctness and performance.
Behavioral equivalence in the polymorphic pi-calculus
Authors: Pierce Benjamin C. , Sangiorgi Davide 
Published: July 2002

We investigateparametric polymorphismin message-based concurrent programming, focusing on behavioral equivalences in a typed process calculus analogous to the polymorphic lambda-calculus of Girard and Reynolds.Polymorphism constrains the power of observers by preventing them from directly manipulating data values whose types are abstract, leading to notions of equivalence much coarser than the standard untyped ones. We study the nature of these constraints through simple examples of concurrent abstract data types and develop basic theoretical machinery for establishing bisimilarity of polymorphic processes.We also observe some surprising interactions between polymorphism and aliasing, drawing examples from both the polymorphic pi-calculus and ML.
A comparison of two network-based file servers
Authors: Mitchell James G. , Dion Jeremy 
Published: July 2002

This paper compares two working network-based file servers, the Xerox Distributed File System (XDFS) implemented at the Xerox Palo Alto Research Center, and the Cambridge File Server (CFS) implemented at the Cambridge University Computer Laboratory. Both servers support concurrent random access to files using atomic transactions, both are connected to local area networks, and both have been in service long enough to enable us to draw lessons from them for future file servers.
We compare the servers in terms of design goals, implementation issues, performance, and their relative successes and failures, and discuss what we would do differently next time.
Eliminating monotonous mathematics with FORMAC
Authors: Tobey Robert G. 
Published: July 2002

The FORMAC (FORmula MAnipulation Compiler) programming system provides a powerful tool for performing mathematical analysis. It is an extension of FORTRAN IV which permits the use of the computer to perform the tedious algebraic computations that arise in many different fields. Among the areas in which it has been successfully used are: differentiation of complicated expressions; expansion of truncated power series, solution of simultaneous equations with literal coefficients, nonlinear maximum likelihood estimation, tensor analysis, and generation of the coefficients of equations in Keplerian motion. These types of analysis—which arose in the solution of specific practical problems in physics, engineering, astronomy, statistics and astronautics—are discussed in the paper.
In addition to its usage for specific problem solutions, FORMAC can also be used to automate the analysis phase in certain production programming. Several such applications are presented.