bluuebunny/crossref_metadata_2025_split huggingface dataset:
Vibration perception thresholds in workers with long term exposure to lead
Authors: Chuang Hung-Yi , Schwartz Joel , Tsai Song-Yen , Lee Mei-Ling Ting , Wang Jung-Der , Hu Howard 
Published: July 2002

OBJECTIVESTo evaluate the impact of long term occupational exposure to lead on function of the peripheral nervous system as reflected by vibration perception threshold (VPT), measured with a portable vibrameter.METHODS217 Workers in a lead battery factory were required to have an annual blood lead measurement during each of the 5 years preceding this study. All were invited to take the VPT test. A total of 206 workers were studied. The associations were analysed between VPTs and current blood lead concentration, mean concentration of blood lead over the past 5 years, maximum blood lead concentration during the past 5 years, index of cumulative blood lead (ICL), time weighted index of cumulative blood lead (TWICL), and percentage of lifespan spent at work in the plant, as well as the other potential confounders. Ordinary multiple regressions, generalised additive models, and hockey stick regression analyses were used to explore the potential existence of a threshold effect of blood lead variables on VPT.RESULTSVPT at a frequency of 220 Hz ranged from 6 to 100 (10-2g, or 0.098 m/s2) with a mean (SD) of 19.8 (14.2) for the feet and from 4 to 43 with a mean (SD) of 10.2 (6.1) for the hands. The five variables of exposure to lead were all significantly correlated with VPT of the feet but not the hands. In multiple linear regression analyses, the mean of the blood lead concentrations and the TWICL were significantly associated with VPT of the feet. The relation between VPT of the feet and mean blood lead was shown to be a J shaped curve with a generalised additive model and local smoothing technique. In the hockey stick regression, evidence was found of a threshold effect at a mean blood lead concentration of 31 μg/dl. Above this threshold it was estimated that each increase of 1 μg/dl mean blood lead over 5 years would increase VPT of the feet by 0.29 (10-2g) or 0.028 m/s2(at a frequency of 220 Hz) with other potential confounders held constant.CONCLUSIONThis study suggests that measurement of vibration sensory threshold is a relatively effective tool for detecting lead neuropathy in field studies, and that lead might cause sensory neuropathy with an effect threshold corresponding to a 5 year mean blood lead concentration of 31 μg/dl.
Association between serum concentrations of hexachlorobenzene and polychlorobiphenyls with thyroid hormone and liver enzymes in a sample of the general population
Authors: Sala M , Sunyer J , Herrero C , To-Figueras J , Grimalt J 
Published: July 2002

OBJECTIVESHexachlorobenzene (HCB) is a highly lipophilic organochlorine compound of widespread environmental occurrence, that accumulates in the biological system. It affects the porphyrine metabolism, thyroid hormones, and the liver function in animals. Although HCB is one of the most common organochlorine compound in humans, little investigation on its health effects has been done. Polychlorobiphenyls (PCBs) are also widespread toxic environmental contaminants. The aim of the present study was to investigate the association of serum HCB and PCB concentrations with thyroid hormone status and liver enzymes in human.METHODSThyroid stimulating hormone (TSH), total and free thyroxine (T4), aspartate aminotransferase (AST), alanine aminotransferase (ALT) and γ-glutamyltransferase (GGT) were measured as biological markers of thyroid and liver function in a rural population sample older than 14 years (n=192, except for TSH with n=608) highly exposed to HCB. Serum concentrations of HCB were measured by gas chromatography coupled to electron capture detection.RESULTSAfter adjustment for confounding variables, there was a significant negative association between serum HCB concentrations and total T4 (a decrease of 0.32 μg/dl per each unit, ln ng/ml, of increase of HCB) and a positive association with GGT (a relative increase of 10 % per each ln unit of increase of HCB), although most subjects (92%) were within the normal range for both T4 and GGT. These associations were not modified after adjustment for total lipid content or for other organochlorine compounds. The association of T4 and GGT with PCB was smaller although significant. No association was found with the other biochemical markers.CONCLUSIONSThese results suggest that the internal dose of HCB of this population may reflect a subtle metabolic effect on thyroid function and an enzymatic induction activity. Further studies are needed to evaluate the health impact of these effects in more susceptible populations, such as infants.
Foetal growth and duration of gestation relative to water chlorination
Authors: Jaakkola J J K , Magnus P , Skrondal A , Hwang B-F , Becher G , Dybing E 
Published: July 2002

OBJECTIVETo assess the effect of exposure to chlorination byproducts during pregnancy on foetal growth and duration of pregnancy.METHODSA population based study was conducted of 137 145 Norwegian children born alive in 1993–5. Information was obtained from the Norwegian medical birth registry, waterwork registry, and social science data service. The outcomes of interest were birth weight, low birth weight (<2500 g), small for gestational age, and preterm delivery (gestational age <37 weeks). The exposure assessment was based on quality of drinking water in the municipality where the mother lived during pregnancy. Municipal exposure was calculated with information on chlorination and the amount of natural organic matter in raw water measured as colour in mg precipitate/l. The main exposure category was high colour and chlorination, which was contrasted with the reference category of low colour and no chlorination.RESULTSIn logistic regression analysis adjusting for confounding, the risks of low birth weight (odds ratio (OR) 0.97, 95% confidence interval (95% CI) 0.89 to 1.06) and small for gestational age (OR 1.00, 95% CI 0.91 to 1.10) were not related to exposure. Contrary to the hypothesis, the risk of preterm delivery was slightly lower among the exposed than the reference category (OR 0.91, 95% CI 0.84 to 0.99). The risks of the studied outcomes were similar in newborn infants exposed to high colour drinking water without chlorination and chlorinated drinking water with low colour compared with the reference category.CONCLUSIONSThe present study did not provide evidence that prenatal exposure to chlorination byproducts at the relatively low concentrations encountered in Norwegian drinking water increases the risk of the studied outcomes.
Role of the vascular endothelium in patients with angina pectoris or acute myocardial infarction with normal coronary arteries
Authors: Sztajzel Juan , Mach François , Righetti Alberto 
Published: July 2002

Summary
Chest pain with normal coronary angiograms is a relatively common syndrome. The mode of presentation of this syndrome includes patients with syndrome X and patients with an acute myocardial infarction and angiographically normal coronary arteries. Different mechanisms have been proposed to elucidate the exact cause and to explain the various clinical presentations in these patients. Abnormalities of pain perception and the presence of oesophageal dysmotility have all been reported in patients with syndrome X. In situ thrombosis or embolization with subsequent clot lysis and recanalization, coronary artery spasm, cocaine abuse, and viral myocarditis have been described as potential mechanisms responsible for an acute myocardial infarction in patients with angiographically normal coronary arteries. Recent data suggest that both microvascular and epicardial endothelial dysfunction may play an important role in the pathophysiological mechanism of the syndrome of stable angina or acute myocardial infarction with normal coronary arteries.
Otorhinolaryngology
Authors: Weir Neil 
Published: July 2002

Summary
Otorhinolaryngology, a product of the early 20th century, developed from the joining together of the separate departments of otology, whose practitioners were surgeons, and laryngology which was managed by physicians who also treated diseases of the nose and chest. The 20th century opened with brave attempts to perform skilful surgery under conditions of primitive anaesthesia and no antibiotics. The stimulus of two world wars led to significant advances in technology and greater opportunities to explore new and resurrect old surgical procedures. The discovery of antibiotics saw an end to acute mastoiditis and the complications of otitis media and sinusitis, as well as a decline in the number of tonsillectomy and adenoidectomy operations.
Over the last 30 years the specialty has undergone dramatic development and has taken advantage of new advances in endoscopy, microsurgery, the use of lasers, cytotoxic drugs, flap reconstruction and microchip technology. During the same period, although still calling themselves otorinolaryngologists, individual surgeons have subspecialised in otology, otoneurosurgery and skull-base surgery, head and neck surgery, phonosurgery, rhinology and facioplastic surgery, and paediatric otothinolaryngology. Each of these subspecialties has its own societies and specialist journals.
The Effects of Long-Term Herbal Treatment for Pediatric AIDS
Authors: Tani Michio , Nagase Mahiko , Nishiyama Tadao , Yamamoto Tatsutaka , Matusa Rodica 
Published: July 2002

This paper presents our long-term (1992–2000) treatment of pediatric Acquired Immune Deficiency Syndrome (AIDS) patients (maximum 100 children, last three years 65) using native herbal remedies in a voluntary medical assistance program in Constanta, Romania. We primarily report the progress of 10 children at a facility called the "House of Tomorrow" and three other facilities. The long-term (8 years and 8 months) treatment contributed to a drop of the amount of Human Immunodeficiency Virus Ribonucleic Acids (HIV-RNA) below the measurable level for 9 out of 10 patients at the "House of Tomorrow." Furthermore, the treatment led to preservation and increase of the cluster of differentiation (CD4) count, a remarkable decrease in mortality rate, as well as the maintenance of a good quality of life. It took one to three years for the beneficial effects of the treatment to emerge. No side-effects were recognized either clinically or biochemically, nor was there any emergence of drug-resistant strains of HIV as seen with anti-HIV chemical treatments.This paper also refers to which herbal remedies were used and their general mechanism of action.
IN-SITU PHOTOELECTRON SPECTROSCOPY OF MAGNETIC DOTS AND MAGNETIC SEMICONDUCTOR NANOSTRUCTURES
Authors: OSHIMA M. , ONO K. , MIZUGUCHI M. , YAMADA M. , OKABAYASHI J. , FUJIMORI A. , AKINAGA H. , SHIRAI M. 
Published: July 2002

High resolution angle-resolved photoelectron spectroscopy (ARPES) has been performed on magnetic nanostructures which were in-situ grown hetero-epitaxially on GaAs substrates by low temperature molecular beam epitaxy. Sulfur termination of GaAs surfaces enabled the formation of NiAs-type MnSb dots and zinc-blende (zb) type MnAs dots, showing huge magnetoresistance at RT and half-metallic behavior, respectively. ARPES analysis revealed that the zb-MnAs dots show unique valence band feature with Mn 3d-related peak at about 4 eV of binding energy which is quite similar to (Ga,Mn)As DMS films. Zb-CrAs thin films on GaAs with T c higher than RT are found to show the band dispersion within 2 eV near the Fermi edge, which is in good agreement with the FLAPW calculation. We have also found that (Ga,Cr)As DMS thin films have the similar valence band features to zb-CrAs
ON THE COLENGTH OF A VARIETY OF LIE ALGEBRAS
Authors: GIAMBRUNO A. , MISHCHENKO S. , ZAICEV M. 
Published: July 2002

We study the variety of Lie algebras defined by the identity [Formula: see text] over a field of characteristic zero. We prove that, as in the associative case, in the nth cocharacter χn of this variety, every irreducible Sn-character appears with polynomially bounded multiplicity (not greater than n2). Anyway, surprisingly enough, we also show that the colength of this variety, i.e. the total number of irreducibles appearing in χn is asymptotically equal to [Formula: see text].
UNDERSTANDING GESTURES IN MULTIMODAL HUMAN COMPUTER INTERACTION
Authors: KETTEBEKOV SANSHZAR , SHARMA RAJEEV 
Published: July 2002

In recent years because of the advances in computer vision research, free hand gestures have been explored as a means of human-computer interaction (HCI). Gestures in combination with speech can be an important step toward natural, multimodal HCI. However, interpretation of gestures in a multimodal setting can be a particularly challenging problem. In this paper, we propose an approach for studying multimodal HCI in the context of a computerized map. An implemented testbed allows us to conduct user studies and address issues toward understanding of hand gestures in a multimodal computer interface. Absence of an adequate gesture classification in HCI makes gesture interpretation difficult. We formalize a method for bootstrapping the interpretation process by a semantic classification of gesture primitives in HCI context. We distinguish two main categories of gesture classes based on their spatio-temporal deixis. Results of user studies revealed that gesture primitives, originally extracted from weather map narration, form patterns of co-occurrence with speech parts in association with their meaning in a visual display control system. The results of these studies indicated two levels of gesture meaning: individual stroke and motion complex. These findings define a direction in approaching interpretation in natural gesture-speech interfaces.
SQUARES, SCALES AND STATIONARY REFLECTION
Authors: CUMMINGS JAMES , FOREMAN MATTHEW , MAGIDOR MENACHEM 
Published: July 2002

Since the work of Gödel and Cohen, which showed that Hilbert's First Problem (the Continuum Hypothesis) was independent of the usual assumptions of mathematics (axiomatized by Zermelo–Fraenkel Set Theory with the Axiom of Choice, ZFC), there have been a myriad of independence results in many areas of mathematics. These results have led to the systematic study of several combinatorial principles that have proven effective at settling many of the important independent statements. Among the most prominent of these are the principles diamond(♢) and square(□) discovered by Jensen. Simultaneously, attempts have been made to find suitable natural strengthenings of ZFC, primarily by Large Cardinal or Reflection Axioms. These two directions have tension between them in that Jensen's principles, which tend to suggest a rather rigid mathematical universe, are at odds with reflection properties. A third development was the discovery by Shelah of "PCF Theory", a generalization of cardinal arithmetic that is largely determined inside ZFC. In this paper we consider interactions between these three theories in the context of singular cardinals, focusing on the various implications between square and scales (a fundamental notion in PCF theory), and on consistency results between relatively strong forms of square and stationary set reflection.
Construction of test problems in quadratic bivalent programming
Authors: Pardalos Panos M. 
Published: July 2002

A method of constructing test problems for constrained bivalent quadratic programming is presented. For any feasible integer point for a given domain, the method generates quadratic functions whose minimum over the given domain occurs at the selected point.
Certain properties of unconstrained quadratic zero-one programs that determine the difficulty of the test problems are also discussed. In addition, a standardized random test problem generator for unconstrained quadratic zero-one programming is given.
A database cache for high performance and fast restart in database systems
Authors: Elhardt Klaus , Bayer Rudolf 
Published: July 2002

Performance in database systems is strongly influenced by buffer management and transaction recovery methods. This paper presents the principles of the database cache, which replaces the traditional buffer. In comparison to buffer management, cache management is more carefully coordinated with transaction management, and integrates transaction recovery. High throughput of
small- and medium-sized transactions is achieved by fast commit processing and low database traffic. Very fast handling of transaction failures and short restart time after system failure are guaranteed in such an environment. Very long retrieval and update transactions are also supported.
Polyhedral subdivision methods for free-form surfaces
Authors: Nasri Ahmad H. 
Published: July 2002

One of the central issues in computer-aided geometric design is the representation of free-form surfaces which are needed for many purposes in engineering and science. Several limitations are imposed on most available surface systems: the rectangularity of the network describing a surface and the manipulation of surfaces without regard to the volume enclosed are examples. Polyhedral subdivision methods suggest themselves as a solution to these problems. Their use, however, is not widespread for several reasons such as the lack of boundary control, and interpolation and interrogation capabilities.
In this paper the original work on subdivision methods is extended to overcome these problems. Two methods are described, one for controlling the boundary curves of such surfaces, and another for interpolating points on irregular networks. A general surface/surface intersection algorithm is also provided: seven decisions need to be made in order to specify a particular implementation. The algorithm is also suitable for intersecting other classes of surfaces amongst which are the popular Bézier and B-spline surfaces.
Correctness of query execution strategies in distributed databases
Authors: Ceri S. , Pelagatti G. 
Published: July 2002

A major requirement of a Distributed DataBase Management System (DDBMS) is to enable users to write queries as though the database were not distributed (distribution transparency). The DDBMS transforms the user's queries into execution strategies, that is, sequences of operations on the various nodes of the network and of transmissions between them. An execution strategy on a distributed database is correct if it returns the same result as if the query were applied to a nondistributed database.
This paper analyzes the correctness problem for query execution strategies. A formal model, called Multirelational Algebra, is used as a unifying framework for this purpose. The problem of proving the correctness of execution strategies is reduced to the problem of proving the equivalence of two expressions of Multirelational Algebra. A set of theorems on equivalence is given in order to facilitate this task.
The proposed approach can be used also for the generation of correct execution strategies, because it defines the rules which allow the transformation of a correct strategy into an equivalent one. This paper does not deal with the problem of evaluating equivalent strategies, and therefore is not in itself a proposal for a query optimizer for distributed databases. However, it constitutes a theoretical foundation for the design of such optimizers.
Introduction to a system for distributed databases (SDD-1)
Authors: Rothnie J. B. , Bernstein P. A. , Fox S. , Goodman N. , Hammer M. , Landers T. A. , Reeve C. , Shipman D. W. , Wong E. 
Published: July 2002

The declining cost of computer hardware and the increasing data processing needs of geographically dispersed organizations have led to substantial interest in distributed data management. SDD-1 is a distributed database management system currently being developed by Computer Corporation of America. Users interact with SDD-1 precisely as if it were a nondistributed database system because SDD-1 handles all issues arising from the distribution of data. These issues include distributed concurrency control, distributed query processing, resiliency to component failure, and distributed directory management. This paper presents an overview of the SDD-1 design and its solutions to the above problems.
This paper is the first of a series of companion papers on SDD-1 (Bernstein and Shipman [2], Bernstein et al. [4], and Hammer and Shipman [14]).
New results on quantifier elimination over real closed fields and applications to constraint databases
Authors: Basu Saugata 
Published: July 2002

In this paper, we give a new algorithm for quantifier elimination in the first order theory of real closed fields that improves the complexity of the best known algorithm for this problem till now. Unlike previously known algorithms [Basu et al. 1996; Renegar 1992; Heintz et al. 1990], the combinatorial part of the complexity (the part depending on the number of polynomials in the input) of this new algorithm is independent of the number of free variables. Moreover, under the assumption that each polynomial in the input depends only on a constant number of the free variables, the algebraic part of the complexity(the part depending on the degrees of the input polynomials) can also be made independent of the number of free variables. This new feature of our algorithm allow us to obtain a new algorithm for a variant of the quantifier elimination problem. We give an almost optimal algorithm for this new problem, which we call theuniform quantifier elimination problem.Using tthe uniform quantifier elimination algorithm, we give an algorithm for solving a problem arising in the field of constraint databases with real polynomial constraints. We give an algorithm for converting a query with natural domain semantics to an equivalent one with active domain semantics. A nonconstructive version of this result was proved in Benedikt et al. [1998]. Very recently, a constructive proof was also given independently in Benedikt and Libkin [1997]. However, complexity issues were not considered and no algorithm with a reasonable complexity bound was known for this latter problem till now.We also point out interesting logical consequences of this algorithmic result, concerning the expressive power of a constraint query language over the reals. This leads to simpler and constructive proofs for these inexpressibility results than the ones known before.Moreover, our improved algorithm for performing quantifier elimination immediately leads to improved algorithms for several problems for which quantifier elimination is a basic step, for example, the problem of computing the closure of a given semi-algebraic set.
The Synthesis of Recursive Digital Filters
Authors: Holtz Howard , Leondes C. T. 
Published: July 2002

The circumstances and methods of the synthesis of linear digital recursive filters which are both stable and physically realizable are described. It is shown that any amplitude requency transfer function expressible as an even trigonometric rational polynomial can be synthesized by a real stable linear digital recursive filter. The degree of the corresponding difference equation is twice the degree of the denominator of the rational trigonometric polynomial.
A class of even rational trigonometric functions which exhibit pointwise convergence to the deal rectangular low or high-pass amplitude frequency transfer function is chosen. A member of this class is shown to approximate more closely the ideal rectangular filter than does the corresponding classical continuous Butterworth filter. This class of filters is then mechanized. The phase and unit-impulse response functions are calculated for the corresponding difference equations of degrees 2 and 4.