bluuebunny/crossref_metadata_2025_split huggingface dataset:
Crystal Structure of Dibromo(η4-1,5-cyclooctadiene)palladium(II)
Authors: Štěpnička Petr , Císařová Ivana 
Published: July 2002

The crystal structure of [(η4-C8H12)PdBr2] has been determined by a single crystal X-ray diffraction with R = 3.82% for 2 147 independent diffractions. The compound crystallizes with the symmetry of orthorhombic space group P212121 (No. 19) within the following parameters: a = 7.0785(5) Å, b = 11.1896(9) Å, c = 12.514(1) Å, V = 991.2(1) Å3, Z = 4. The square planar arrangement of ligands around Pd(II) is distorted due to the steric requirements of 1,5-cyclooctadiene in a twisted boat conformation. Formula units are joined by the weak C2-H2...Br1(1 + x, y, z) hydrogen bonds.
3-Bromo-2,5-dihydrofuran-2-one and 4-Bromo-2,5-dihydrofuran-2-one
Authors: Brecker Lothar , Kreiser Wolfgang , Ernst Ludger , Hopf Henning 
Published: July 2002

Although 3-bromo-2,5-dihydrofuran-2-one and 4-bromo-2,5-dihydrofuran-2-one were first reported in 1894, considerable ambiguity still exists about the correct structure assignment of the two compounds. The present article gives a brief overview on the varying assignments of constitution and describes a novel method for the formation of 3-bromo-2,5-dihydrofuran-2-one. A comparison is made of the experimental 13C NMR chemical shifts with values predicted by increment calculations and experimental 1JC-C coupling constants are given for both compounds. Secure structural assignments are now available for both isomers.
Exposure to benzene, occupational stress, and reduced birth weight
Authors: Chen Dafang , Cho Sung-Il , Chen Changzhong , Wang Xiaobin , Damokosh Andrew I , Ryan Louise , Smith Thomas J , Christiani David C , Xu Xiping 
Published: July 2002

OBJECTIVESThe association between birth weight and exposure to benzene, work stress, and other occupational and environmental hazards was investigated.METHODSIn a large petrochemical industry, 792 pregnant workers were enrolled and followed up through delivery between May 1996 and December 1998. Exposure to benzene and other solvents was assessed by an industrial hygienist based on each woman's job title and workplace information. Other occupational and environmental exposures and personal information, including perceived work stress, exposure to noise, physical exertion at work, and passive smoking, were obtained by an interview questionnaire. Univariate and multivariate regression models were used to examine the individual and combined associations of occupational and environmental exposures with birth weight, with adjustment for major confounders including gestational age.RESULTSIn the univariate model, birth weight was negatively associated with exposure to benzene (−58 g (95% confidence interval (95% CI), −115 to −2)) and with work stress (−84 g (95% CI, −158 to −10)). In the multivariate model, there was a significant interaction between exposure to benzene and work stress relative to reduced birth weight, after adjustment for other environmental and occupational exposures and personal variables. Adjusted mean birth weight was 3445 g (95% CI 3401 to 3489) among those with neither exposure, 3430 g for those with exposure to benzene only, 3426 g for those with work stress only, and 3262 g (95% CI 3156 to 3369) for those with both exposures. In other words, there was 183 g (95% CI 65 to 301) reduction in birth weight among those with both exposure to benzene and work stress compared with those with neither exposure. Other work or environmental factors could not explain these findings.CONCLUSIONSLow level exposure to benzene and work stress interact to reduce birth weight in this population.
Behçet’s disease
Authors: Kontogiannis V , Powell R J 
Published: July 2002

Abstract
Behçet’s disease is a systemic vasculitis of unknown aetiology characteristically affecting venules. Onset is typically in young adults with recurrent oral and genital ulceration, uveitis, skin manifestations, arthritis, neurological involvement, and a tendency to thrombosis. It has a worldwide distribution but is prevalent in Japan, the Middle East, and some Mediterranean countries. International diagnostic criteria have been proposed, however diagnosis can be problematical, particularly if the typical ulcers are not obvious at presentation. Treatment is challenging, must be tailored to the pattern of organ involvement for each patient and often requires combination therapies.
Poisson Spaces with a Transition Probability
Authors: Landsman N. P. 
Published: July 2002

The common structure of the space of pure states ℘ of a classical or a quantum mechanical system is that of a Poisson space with a transition probability. This is a topological space equipped with a Poisson structure, as well as with a function p:℘×℘→[0,1], with certain properties. The Poisson structure is connected with the transition probabilities through unitarity (in a specific formulation intrinsic to the given context). In classical mechanics, where p(ρ,σ)=δρσ, unitarity poses no restriction on the Poisson structure. Quantum mechanics is characterized by a specific (complex Hilbert space) form of p, and by the property that the irreducible components of ℘ as a transition probability space coincide with the symplectic leaves of ℘ as a Poisson space. In conjunction, these stipulations determine the Poisson structure of quantum mechanics up to a multiplicative constant (identified with Planck's constant). Motivated by E. M. Alfsen, H. Hanche-Olsen and F. W. Shultz (Acta Math.144 (1980) 267–305) and F.W. Shultz (Commun. Math. Phys.82 (1982) 497–509), we give axioms guaranteeing that ℘ is the space of pure states of a unital C*-algebra. We give an explicit construction of this algebra from ℘.
CdTe and Si SOLAR CELL PERFORMANCE COMPARISON IN A NEW SYSTEM FOR SOLAR ENERGY CONVERSION AND STORAGE
Authors: MORALES-SÁNCHEZ E. , GONZÁLEZ-HERNÁNDEZ J. , RAMÍREZ-BON R. , ESPINOZA-BELTRÁN F. , VOROBIEV Y. , MORALES-ACEVEDO A. , GORLEY PETRO , KOVALYUK Z. , HORLEY PAUL 
Published: July 2002

A new system for the effective conversion and storage of solar energy using CdTe and Si based photovoltaic solar cells and the Li- Bi 2 Se 3 rechargable batteries was created and studied. PV Solar Cells with the different types of structure and barrier were studied (Shottky. MIS with thin insulating layer, and p-n junction), employing low-temperature and high-temperature technological cycles. The influence of the technological details upon the electrical parameters as well as the efficiency and stability of their performance were analyzed, and also the condition for improving the efficiency were found. In particular, it was established that Zn-doping of CdTe and the Al alloying to Si at 800°C have a profound effect upon the PV cell characteristics. The influence of the recombination in different parts of the cell upon the cell's efficiency and the recombination dependence upon the technological features were investigated. A comparison of the performance and fabrication cost of the new systems for solar energy conversion and storage with others using conventional cells and batteries is made. It is shown that newly developed systems could provide a global efficiency close to that for traditional ones, with simpler and cheaper technology. With some modifications of the technology, we expect to get even higher efficiencies and a wider system operation temperature range. The possibilities are discussed for the creation of a hybrid energy conversion system on the basis of our cells and batteries, with an overall efficiency of transformation of solar-to-electric energy around 40%.
SIMULTANEOUS REPRESENTATIONS OF SEMILATTICES BY LATTICES WITH PERMUTABLE CONGRUENCES
Authors: TŮMA JIŘÍ , WEHRUNG FRIEDRICH 
Published: July 2002

The Congruence Lattice Problem (CLP), stated by R. P. Dilworth in the forties, asks whether every distributive {∨, 0}-semilattice S is isomorphic to the semilattice Con c L of compact congruences of a lattice L. While this problem is still open, many partial solutions have been obtained, positive and negative as well. The solution to CLP is known to be positive for all S such that |S|≤ℵ1. Furthermore, one can then take Lwith permutable congruences. This contrasts with the case where |S|≥ℵ2, where there are counterexamples S for which Lcannot be, for example, sectionally complemented. We prove in this paper that the lattices of these counterexamples cannot have permutable congruences as well. We also isolate finite, combinatorial analogues of these results. All the "finite" statements that we obtain are amalgamation properties of the Con c functor. The strongest known positive results, which originate in earlier work by the first author, imply that many diagrams of semilattices indexed by the square22 can be lifted with respect to the Con c functor. We prove that the latter results cannot be extended to the cube, 23. In particular, we give an example of a cube diagram of finite Boolean semilattices and semilattice embeddings that cannot be lifted, with respect to the Con c functor, by lattices with permutable congruences. We also extend many of our results to lattices with almost permutable congruences, that is, α∨β=αβ ∪βα, for all congruences α and β. We conclude the paper with a very short proof that no functor from finite Boolean semilattices to lattices can lift the Con c functor on finite Boolean semilattices.
MONOIDS WITH IDEMPOTENT CROSS-SECTIONS
Authors: PUTCHA MOHAN S. 
Published: July 2002

In this paper we consider monoids M with an idempotent cross-section Λ of regular [Formula: see text]-classes such that for all idempotents e, f of M with e≥f, there exists x in the unit group such that x-1ex, x-1fx∈Λ. Such monoids arise frequently in connection with group representations. We show that Λ is then necessarily a semilattice and that the idempotent structure of M can for the most part, be determined within the unit group. We identify a particular class of "canonical monoids" inspired by some projective compactifications of algebraic groups. We show that these canonical monoids are 0-semilattice unions of completely 0-simple semigroups.
THE MORPHOGENESIS OF HIGH SYMMETRY: THE SYMMETRIZATION THEOREM
Authors: MARZEC CHRISTOPHER J. 
Published: July 2002

A multi-part theorem is presented concerning the morphogenesis of high-symmetry structures made of three-dimensional morphological units (MU's) free to move on the surface of a sphere. All parts of each MU interact non-specifically with the remainder of the structure, via an isotropic function of distance. Summing all interactions gives a net figure of merit, ℐ, that depends upon MU positions and orientations. The structure evolves via gradient dynamics, each MU moving down the local gradient of ℐ. The analysis is reresented with generality in Fourier space, which eases the expression of symmetry. Structures near symmetry, but far from a local minimum of ℐ, are analyzed. For each, a symmetrical configuration can be found, for which ℐ is an extremum with respect to symmetry-breaking perturbations. Under gradient dynamics, a quadratic measure of such deviations from symmetry decreases monotonically, anywhere in the large basin of attraction of a local minimum. Thus: high symmetry is an attractor. Application is made to icosahedral virus capsids. The Symmetrization Theorem shows that a stable capsid, maintained by non-specific interactions among its capsomeres, could arise generically in a "bottom-up" process. For animated evolutions that self-assemble into high symmetry, visit
NEW TARGETS FOR THE STUDIES OF BIOMECHANICAL, ENDOCRINOLOGIC, GENETIC AND PHARMACEUTICAL EFFECTS ON BONES: BONE'S "NEPHRON EQUIVALENTS", MUSCLE, NEUROMUSCULAR PHYSIOLOGY
Authors: Frost Harold M. 
Published: July 2002

As age, experience and common sense look at biomechanical, hormonal, genetic and other roles in bone physiology and its disorders, two questions can arise: (a) How did we fail? (b) How could we make it better? The acerbic Sam Johnson said that to teach new things, we should use examples of already known ones. If so, an analogy might help to clarify this article's message for people who work with bones and their disorders. Assume this: (a) Mythical physiologists were taught that renal physiology depends on "kidney cells" but were taught nothing about nephrons; (b) so they explained renal health and disorders in those terms. (c) For many decades, they "knew" that view was correct (as the ancients "knew" the world was flat). (d) But then others described nephrons and some errors their properties revealed in those views about renal physiology; (e) so controversies began. Today, an analogous situation confronts real biomechanicians and physiologists. (i) Most of them were taught that osteoblasts and osteoclasts (bone's "effector cells") explain bone physiology without "nephron-equivalent" input, so they explained bone disorders and mechanical effects in those terms. (ii) Yet nephron-equivalent mechanisms and functions, including biomechanical ones, in bones have the same operational relationship to their cells, health and disorders as nephrons and their functions do to renal cells, health and disorders. (iii) Adding that knowledge to former views led to the Utah paradigm of skeletal physiology. It also revealed errors in many former views about bone physiology; (iv) so real controversies have begun. Biomechanicians, physiologists, clinicians and pharmacologists from whom poor interdisciplinary communication hid that paradigm could think the view in (i) above remains valid, and keep analyzing data and designing studies within its constraints. Like Wegner's idea of plate tectonics in geology, the Utah paradigm came before its field was ready, so others fought it. But while the plate-tectonics war was won, it has just begun for the Utah paradigm. This article reviews how such things could apply to bone and some of their implications. Its conclusion offers succinct answers to the italicized questions above.
MODULAR CONNECTIONIST MODELLING AND CLASSIFICATION APPROACHES FOR LOCAL DIAGNOSIS IN TELECOMMUNICATION TRAFFIC MANAGEMENT
Authors: BENNANI YOUNÈS , BOSSAERT FABRÌCE 
Published: July 2002

In Neural Networks (NN) applications, it is common practice to train several different networks and select the best one on the basis of performance on a validation set. There is a major disadvantage of such an approach: the network with the best performance on the validation set might not be the best one on new test data. In fact, the generalization performance on the validation set has a random component that is due to the data noise. An alternative approach to this problem is to use a combination of multiple NN classifiers. It is well known that such combinations can produce better performance than the best single network used in isolation. Several studies in different fields of the pattern recognition have experimentally shown that an appropriate combination of NN classifiers allows to capture complex phenomena, and to make decisions even with a great deal of information.3,11,12 The combination of multiple classifiers is a general problem in the pattern recognition area. Several methods for combining the outputs of multiple classifiers have been proposed: ensemble methods,14 boosting approaches,9 stacking techniques,27 multi-expert systems,2,16 and multi-modular architectures.3,13,18 A very rich synthesis of different methods of combining classifiers can be found in Ref. 28. An analytical framework to quantify the improvements in classification results that is due to combining classifiers is provided in Ref. 26. In this paper some contributions in combining multiple NN classifiers are presented. We give a combinational approach based on multi-modular systems for local diagnosis problem in the telephone network. In addition, we propose a combinational method for discrimination task using a fusion. The system validation will be performed on a disturbance identification problem.
PILOT—A New Multiple Computer System
Authors: Leiner A. L. , Notz W. A. , Smith J. L. , Weinberger A. 
Published: July 2002

The PILOT data processor is a high-speed multiple computer system, more than 100 times faster than SEAC. It contains three interconnected computers for rapid processing of data, and also contains multiple input-output channels for rapid transfer of data into and out of the system. All of these units operate concurrently in a coordinated fashion. A summary description is given of the over-all logical plan of the system, including the principal characteristics of the first computer, the second computer, the third computer, the internal controls, and the external controls.
The system combines internal processing capabilities that are fast and versatile with external communication capabilities that are exceptionally flexible. This combination permits the internal power of the machine to be exploited readily by the outside world,—either by other automatic devices or by human operators.
The Placement of Computer Logic Modules
Authors: Mamelak J. S. 
Published: July 2002

The object of the work described was to develop a procedure for the allocation of logic to cards, boards, platters and so on which utilize modular circuit design and etched wiring techniques.
A chain of logic elements is a set of interconnected (logic) elements two of which connect to, at least, the remaining elements of this set. Every logic diagram has a characteristic set of chains. A subset of these chains is selected to initiate the determination of the locations of each element on a card. The elements of a chain are assigned to one row or column of platter locations. The positions of the chains in relation to one another are determined by such criteria as total wire length reduction, proximity requirements between gates based on electrical considerations and the proximity requirements between elements and pins based on timing considerations.
The effectiveness of the automatic procedure was tested during the design of small cards (mounting 16 modules, up to 64 gates). In these circumstances human experience and insight are at their best. The layouts of experienced technicians and engineers were compared with the layouts produced by the program. Significant similarities between the determinations were found in all cases tested.
Samplesort: A Sampling Approach to Minimal Storage Tree Sorting
Authors: Frazer W. D. , McKellar A. C. 
Published: July 2002

The methods currently in use and previously proposed for the choice of a root in minimal storage tree sorting are in reality methods for making inefficient statistical estimates of the median of the sequence to be sorted. By making efficient use of the information in a random sample chosen during input of the sequence to be sorted, significant improvements over ordinary minimal storage tree sorting can be made.
A procedure is proposed which is a generalization of minimal storage tree sorting and which has the following three properties: (a) There is a significant improvement (over ordinary minimal storage tree sorting) in the expected number of comparisons required to sort the input sequence. (b) The procedure is statistically insensitive to bias in the input sequence. (c) The expected number of comparisons required by the procedure approaches (slowly) the information-theoretic lower bound on the number of comparisons required. The procedure is, therefore, “asymptotically optimal.”
Recent Studies in Automatic Text Analysis and Document Retrieval
Authors: Salton G. 
Published: July 2002

Many experts in mechanized text processing now agree that useful automatic language analysis procedures are largely unavailable and that the existing linguistic methodologies generally produce disappointing results. An attempt is made in the present study to identify those automatic procedures which appear most effective as a replacement for the missing language analysis.
A series of computer experiments is described, designed to simulate a conventional document retrieval environment. It is found that a simple duplication, by automatic means, of the standard, manual document indexing and retrieval operations will not produce acceptable output results. New mechanized approaches to document handling are proposed, including document ranking methods, automatic dictionary and word list generation, and user feedback searches. It is shown that the fully automatic methodology is superior in effectiveness to the conventional procedures in normal use.
The effects of multiplexing on a computer-communications system
Authors: Pack Charles D. 
Published: July 2002

A study is made of the way in which asynchronous time division multiplexing changes the stochastic nature of the arrival process from a user to the computer and, consequently, affects the performance of a time-shared computer-communications system. It is concluded that while, for certain values of system parameters, there is noticeable improvement in the performance of the computer (model), in the sense that time-shared scheduling delays are reduced, these improvements are offset by the transmission delays imposed by multiplexing so that there may be little or no change in the computer-communications system performance.
Analytical and simulation results are based on the model of the computer-communications system being an M/D/1 queue (the multiplexor) in tandem with a single exponential server (the computer). Analytical results include a general description of the output process of an M/D/1 queue and the conditions under which this output process is approximately Poisson.
An interactive command generating facility
Authors: Grant Charles A. 
Published: July 2002

A facility to permit conversationally controlled tasks to be executed in a noninteractive environment is proposed. A means by which programs can generate interactive time-sharing commands and receive the corresponding output response is presented. The commands will be invoked as if they had been typed at a console keyboard. It is argued that this facility will help overcome some of the current limitations in man-computer communication.
A set of functions to accomplish the above which could be embedded into any string processing language is suggested, and necessary information pertinent to implementation of the facility on existing time-sharing systems is given.
Conversational access to a 2048-word machine
Authors: Wilkes Mary Allen 
Published: July 2002

LAP6 is an on-line system running on a 2048-word LINC which provides full facilities for text editing, automatic filing and file maintenance, and program preparation and assembly. It focuses on the preparation and editing of continuously displayed 23,040-character text strings (manuscripts) which can be positioned anywhere by the user and edited by simply adding and deleting lines as though working directly on an elastic scroll. Other features are available through a uniform command set which itself can be augmented by the user.
The machine, although small, aids program design by providing display scope and premarked randomly addressable LINC tapes as standard items, in an environment similar to that of a sophisticated terminal. The tapes are logically similar to a disk. Priority was given to the design of efficient tape algorithms to minimize the limitations of the small memory. Techniques developed for handling scroll editing, filing, and the layered system structure are outlined.
LAP6 is used by about 2000 people in 11 countries. Its design was strongly influenced by performance criteria established in interviews held with the LINC users themselves during the specification period.