bluuebunny/crossref_metadata_2025 huggingface dataset:
Detecting Protein-Protein Interactions in the Intact Cell of
Bacillus subtilis
(ATCC 6633)
Authors: Winters Michael S. , Day R. A.
Published: July 2003

The salt bridge, paired group-specific reagent cyanogen (ethanedinitrile; C
2
N
2
) converts naturally occurring pairs of functional groups into covalently linked products. Cyanogen readily permeates cell walls and membranes. When the paired groups are shared between associated proteins, isolation of the covalently linked proteins allows their identity to be assigned. Examination of organisms of known genome sequence permits identification of the linked proteins by mass spectrometric techniques applied to peptides derived from them. The cyanogen-linked proteins were isolated by polyacrylamide gel electrophoresis. Digestion of the isolated proteins with proteases of known specificity afforded sets of peptides that could be analyzed by mass spectrometry. These data were compared with those derived theoretically from the Swiss Protein Database by computer-based comparisons (Protein Prospector;
http://prospector.ucsf.edu
). Identification of associated proteins in the ribosome of
Bacillus subtilis
strain ATCC 6633 showed that there is an association homology with the association patterns of the ribosomal proteins of
Haloarcula marismortui
and
Thermus thermophilus
. In addition, other proteins involved in protein biosynthesis were shown to be associated with ribosomal proteins.
Structural Insight into the Antibiotic Action of Telithromycin against Resistant Mutants
Authors: Berisio Rita , Harms Joerg , Schluenzen Frank , Zarivach Raz , Hansen Harly A. S. , Fucini Paola , Yonath Ada
Published: July 2003

The crystal structure of the ketolide telithromycin bound to the
Deinococcus radiodurans
large ribosomal subunit shows that telithromycin blocks the ribosomal exit tunnel and interacts with domains II and V of the 23S RNA. Comparisons to other clinically relevant macrolides provided structural insights into its enhanced activity against macrolide-resistant strains.
Crystal Structures of
Mycobacterium smegmatis
RecA and Its Nucleotide Complexes
Authors: Datta S. , Krishna R. , Ganesh N. , Chandra Nagasuma R. , Muniyappa K. , Vijayan M.
Published: July 2003

The crystal structures of
Mycobacterium smegmatis
RecA (RecA
Ms
) and its complexes with ADP, ATPγS, and dATP show that RecA
Ms
has an expanded binding site like that in
Mycobacterium tuberculosis
RecA, although there are small differences between the proteins in their modes of nucleotide binding. Nucleotide binding is invariably accompanied by the movement of Gln 196, which appears to provide the trigger for transmitting the effect of nucleotide binding to the DNA-binding loops. These observations provide a framework for exploring the known properties of the RecA proteins.
An Integrated Structural and Computational Study of the Thermostability of Two Thioredoxin Mutants fromAlicyclobacillus acidocaldarius
Authors: Bartolucci Simonetta , De Simone Giuseppina , Galdiero Stefania , Improta Roberto , Menchise Valeria , Pedone Carlo , Pedone Emilia , Saviano Michele
Published: July 2003

We report a crystallographic and computational analysis of two mutant forms of theAlicyclobacillus acidocaldariusthioredoxin (BacTrx) done in order to evaluate the contribution of two specific amino acids to the thermostability of BacTrx. Our results suggest that the thermostability of BacTrx may be modulated by mutations affecting the overall electrostatic energy of the protein.
Evaluation of abnormal liver function tests
Authors: Limdi J K , Hyde G M
Published: July 2003

Interpretation of abnormalities in liver function tests is a common problem faced by clinicians. This has become more common with the introduction of automated routine laboratory testing. Not all persons with one or more abnormalities in these tests actually have liver disease. The various biochemical tests, their pathophysiology, and an approach to the interpretation of abnormal liver function tests are discussed in this review.
Emergency management of atrial fibrillation
Authors: Wakai A , O’Neill J O
Published: July 2003

Atrial fibrillation is the most common cardiac arrhythmia managed by emergency and acute general physicians. There is increasing evidence that selected patients with acute atrial fibrillation can be safely managed in the emergency department without the need for hospital admission. Meanwhile, there is significant variation in the current emergency management of acute atrial fibrillation. This review discusses evidence based emergency management of atrial fibrillation. The principles of emergency management of acute atrial fibrillation and the subset of patients who may not need hospital admission are reviewed. Finally, the need for evidence based guidelines before emergency department based clinical pathways for the management of acute atrial fibrillation becomes routine clinical practice is highlighted.
Osteoporosis and exercise
Authors: Todd J A , Robinson R J
Published: July 2003

Osteoporosis is a common medical problem. Lifestyle measures to prevent or help treat existing osteoporosis often only receive lip service. The evidence for the role of exercise in the prevention and treatment of osteoporosis is reviewed.
Post-exposure prophylaxis for blood borne viral infections in healthcare workers
Authors: Varghese G M , Abraham O C , Mathai D
Published: July 2003

Healthcare workers have a high risk of occupational exposure, more so in developing countries, with high incidence of blood borne diseases and prevalence of unsafe practices. Among the various blood borne diseases, the most common and important ones are HIV infection, hepatitis B, and hepatitis C. Most of the occupational transmission can be prevented and the “standard precaution” has been shown to reduce exposures and hence the transmission of infection. Healthcare workers have to be educated about post-exposure prophylaxis and each institution needs to adopt a clear protocol.
Primary care referral protocol for wrist ganglia
Authors: Burke F D , Melikyan E Y , Bradley M J , Dias J J
Published: July 2003

The paper summarises current knowledge on ganglia of the wrist including the views of patients and doctors. The efficacy of available treatment options are discussed. Summary points are derived from the available knowledge with a referral protocol from primary care.
Management of stable angina
Authors: Jain A , Wadehra V , Timmis A D
Published: July 2003

Ischaemic heart disease may present as a wide variety of clinical entities including unstable or stable angina pectoris, acute myocardial infarction, and occasionally heart failure. Chronic stable angina is a common condition and results in a considerable burden for both the individual and society. The goals in management are (i) treatment of other conditions that may worsen angina; (ii) modification of risk factors and treatment with medications for coronary artery disease to improve outcome; and (iii) effective relief of anginal symptoms. There are limitations to the methods available to risk-stratify patients, and the optimal treatment strategy remains unclear. The benefits of lifestyle modification cannot be over-emphasised, and appropriate attention to modifiable risk factors is paramount. The mortality benefit of lipid lowering treatment and antiplatelet therapy is well proved. However the evidence base for anti-ischaemic therapy is less rigorous, being based mainly on extrapolations from studies of acute coronary syndromes. Angioplasty has been shown to be more effective in relief of symptoms than medical therapy alone, but provides no mortality benefit. Coronary artery bypass surgery, however, has been shown to reduce mortality in patients with severe proximal coronary disease when compared with medical management alone.
What determines patients’ satisfaction with their mental health care and quality of life?
Authors: Blenkiron P , Hammill C A
Published: July 2003

Objectives

This study investigated whether patients’ satisfaction with their mental health care and quality of life is related to their age, gender, psychiatric diagnosis, and duration of mental disorder.

Method

120 adults of working age who were receiving input from a community mental health team in North Yorkshire were invited to complete the Carers’ and User’s Expectations of Services, User Version (CUES-U) questionnaire. This 16 item self rated outcome measure covers the issues that those using mental health services have identified as being their priorities.

Results

CUES-U ratings were lowest for “Social life” (49% satisfied) and highest for “Relationships with physical health workers” (88% satisfied). Satisfaction with psychiatric services correlated significantly with patients’ age (Spearman’s r = 0.444, p<0.001) and their satisfaction in other areas of their lives such as housing, money, and relationships (r = 0.575, p<0.001). Those with psychotic disorders rated their quality of life as higher than other respondents (median total satisfaction score 12 v 9, Mann-Whitney U = 377, p = 0.001). Gender and duration of disorder were unrelated to service satisfaction.

Conclusions

Patient satisfaction ratings have been promoted as an outcome measure when evaluating the quality of their mental health services. Certain factors influencing an individual’s satisfaction with the care provided (such as their age and general quality of life) are not directly under the control of professionals.
Hospital admissions for human T-cell lymphotropic virus type-1 (HTLV-1) associated diseases in Dominica
Authors: Adedayo O , Grell G , Bellot P
Published: July 2003

Human T-cell lymphotropic virus type 1 (HTLV-1) is a retrovirus that is endemic in certain regions of the world, and may account for significant morbidity and mortality among hospitalised patients.

Sixty six HTLV-1 seropositive patients admitted to hospital with HTLV-1 associated diseases from 1995–99 were studied. HTLV-1 screening was done with ELISA and confirmed on western blot testing. There were 32 females (48.5%) and 34 males (51.5%). The mean age was 56 years and the age range was 9–89 years.

The main associated diseases were tropical spastic paraparesis or HTLV-1 associated myelopathy in 18.2% of cases, acute form of adult T-cell leukaemia/lymphoma 7.6%, lymphomas 15.2%, and ectoparasites/endoparasites in 40.9%. HTLV-1 is associated with diseases in Dominica and association with severe forms of strongyloidiasis and scabies is particularly noted.
Spontaneous pneumothorax: use of aspiration and outcomes of management by respiratory and general physicians
Authors: Packham S , Jaiswal P
Published: July 2003

Background

Spontaneous pneumothorax is a common problem in hospital practice. Despite the publication of guidelines controversy over its initial management still exists, particularly over the use of simple aspiration.

Methods

The management of spontaneous pneumothorax by respiratory and general physicians at our hospital was analysed by retrospective case note review. Eighty five patients were identified over the study period (36 managed by respiratory and 49 by general physicians).

Results

There was a significantly greater use of simple aspiration by respiratory (81%) than general physicians (47%, p<0.001) and a higher rate of success in this group. As a result those patients managed by respiratory physicians had fewer intercostal drains inserted and significantly shorter length of stays (mean 5.6 (3.8) days respiratory group and 9.5 (6.8) days in general physicians group, p<0.05).

Conclusions

The greater and more successful use of simple aspiration by respiratory physicians as an initial treatment for spontaneous pneumothorax resulted in improved outcomes and reduced length of hospital stays.
Aortic aneurysm replacement with Dacron graft in a 34 year old man. How long will the graft last?
Authors: Khan B F , Renton S , Hussain S T
Published: July 2003

A unique case of an abdominal aortic aneurysm replacement in a young man of Caribbean descent is presented. The initial working diagnosis was of a mycotic aneurysm, which has recently shown resurgence with intravenous drug abuse. Blood tests and subsequent biopsy ruled that out. There was also a clinical suspicion of a connective tissue abnormality. Histological examination of the aneurysm, skin biopsy, and blood tests also ruled out this possibility. The graft used in this patient was from a new generation of grafts. In the absence of any studies on such grafts, there is the question of long term durability of the graft.
Surgical presentation of ischaemic hepatitis
Authors: Powell L , Tesfaye S , Ackroyd R , Sanders D S
Published: July 2003

Intestinal ischaemia typically presents with signs suggestive of an acute surgical abdomen. A raised serum lactate may substantiate the diagnosis. The first case of ischaemic hepatitis mimicking intestinal ischaemia is reported. The recognition of markedly deranged transaminases allows the clinician to differentiate the two diagnoses and potentially avoid the risks incurred with laparotomy.
Magnetic resonance imaging in rabies
Authors: Mani J , Reddy B C , Borgohain R , Sitajayalakshmi S , Sundaram C , Mohandas S
Published: July 2003

Rabies encephalitis has a classical clinical presentation and its diagnosis is unmistakable. In about a fifth of cases rabies occurs as its paralytic form, which lacks the classic symptoms and may mimic other diseases, especially acute disseminated encephalomyelitis (ADEM). Magnetic resonance imaging of the brain in rabies shows a distinct abnormal pattern that differentiates it from ADEM. Hence it may be a useful tool in diagnosis of paralytic rabies. Failure to administer post-exposure rabies immunoglobulin along with the rabies vaccine may result in vaccine failure.
FORMAL PROOF OF APPLICATIONS DISTRIBUTED IN SYMMETRIC INTERCONNECTION NETWORKS
Authors: GASCARD ERIC , PIERRE LAURENCE
Published: July 2003

This paper focuses on the formal proof of parallel programs dedicated to distributed memory symmetric interconnection networks; communications are realized by message passing. We have developed a method to formally verify the computational correctness of this kind of application. Using the notion of Cayley graphs to model the networks in the Nqthm theorem prover, we have formally specified and mechanically proven correct a large set of collective communication primitives. Our compositional approach allows us to reuse these libraries of pre-proven procedures to validate complex application programs within Nqthm. This is illustrated by three examples.
A NOTE ON LINEARIZABILITY AND THE GLOBAL TIME AXIOM
Authors: CHARRON-BOST BERNADETTE , CORI ROBERT
Published: July 2003

The assumption of the existence of global time, which significantly simplifies the analysis of distributed systems, is generally safe since most of the conclusions obtained under the global time axiom can be transferred to the frame where no such assumption is made. In this note, we show that the compositionality of the well-known correctness condition for concurrent objects called linearizability does not satisfy this simplification rule: we present a simple non-linearizable system composed of two objects which are individually linearizable.
A SELF-STABILIZING PHASE SYNCHRONIZATION PROTOCOL
Authors: CHIAO YIWEI
Published: July 2003

This paper presents a quorum-based self-stabilizing protocol for the phase synchronization problem. In the protocol, nodes proceed in a cyclic sequence of K phases, K > 2. The phases for any two nodes in the system can be at most one apart. This protocol is suited to work with many existing quorum-based protocols.
OPTIMAL GOSSIPING ON CCCs OF EVEN DIMENSION
Authors: SIBEYN JOP F. , ŠOCH MICHAL
Published: July 2003

A heuristic has shown that the results achieved by earlier algorithms for gossiping on cube-connected-cycles (CCCs) in the unit-cost telephone model were not optimal, but no general pattern was revealed. In this paper new gossiping algorithms are presented that apply to CCCs of all sizes. Most importantly, we show that for gossiping on the "k-dimensional" network, CCCk, with k even, gossiping can be performed in 5/2 · k - 2 communication rounds, which exactly matches the lower bound, thus completely solving the gossiping problem for these networks. For odd k we improve upon the best previous algorithm without matching the lower bound.
QoS ROUTING IN HYPERCUBE MULTICOMPUTERS
Authors: WU JIE , DAI FEI
Published: July 2003

In this paper, we present a coding method to capture QoS information in hypercube multicomputers. The coding method is based on a localized algorithm where each node interacts with its neighbors to gather QoS information. Specifically, each node maintains a QoS vector where the k-th element represents the guaranteed QoS performance to a destination that is k hops away. The localized algorithm exhibits desirable properties of self-stabilizing, self-optimizing, and self-healing. Simulation results show that this coding method provides a good approximation of the minimum QoS value to a k-hop destination and, at the same time, uses a relatively small number of packets to propagate a change in link state (QoS value) compared with the classical distributed Bellman-Ford method.
EXECUTION OF SEQUENTIAL AND PARALLEL JAVA BYTECODE IN A METACOMPUTING SYSTEM
Authors: GAMESS ERIC
Published: July 2003

In this paper, we address the goal of executing Java parallel applications in a group of nodes of a Beowulf cluster transparently chosen by a metacomputing system oriented to efficient execution of Java bytecode, with support for scientific computing. To this end, we extend the Java virtual machine by providing a message passing interface and quick access to distributed high performance resources. Also, we introduce the execution of parallel linear algebra methods for large objects from sequential Java applications by invoking SPLAM, our parallel linear algebra package.
PARALLEL REAL-TIME COMPUTATION OF NONLINEAR FEEDBACK FUNCTIONS
Authors: AKL SELIM G.
Published: July 2003

This paper focuses on the improvement in the quality of computation provided by parallelism. The problem of interest is that of computing the maximum of a nonlinear feedback function in a real-time environment. We show that the solution obtained in parallel is significantly, provably, and consistently better than a sequential one. It is important to note that our purpose is not to demonstrate merely that a parallel computer can obtain a solution to a computational problem that is of higher quality than one derived sequentially. The latter is an interesting (and often surprising) observation in its own right, but we wish to go further. It is shown here that the improvement in quality due to parallelism can be arbitrarily high. To be specific, the ratio of the parallel solution to the sequential one is typically superlinear in the number of processors used by the parallel computer. This result is akin to superlinear speedup—a phenomenon itself originally thought to be impossible.
COMBINING SPECTRAL SEQUENCING AND PARALLEL SIMULATED ANNEALING FOR THE MINLA PROBLEM
Authors: PETIT JORDI
Published: July 2003

In this paper we present and analyze new sequential and parallel heuristics to approximate the Minimum Linear Arrangement problem (MinLA). The heuristics consist in obtaining a first global solution using Spectral Sequencing and improving it locally through Simulated Annealing. In order to accelerate the annealing process, we present a special neighborhood distribution that tends to favor moves with high probability to be accepted. We show how to make use of this neighborhood to parallelize the Metropolis stage on distributed memory machines by mapping partitions of the input graph to processors and performing moves concurrently. The paper reports the results obtained with this new heuristic when applied to a set of large graphs, including graphs arising from finite elements methods and graphs arising from VLSI applications. Compared to other heuristics, the measurements obtained show that the new heuristic improves the solution quality, decreases the running time and offers an excellent speedup when ran on a commodity network made of nine personal computers.
THE STUDY OF GRAVITATIONAL COLLAPSE MODEL IN HIGHER DIMENSIONAL SPACETIME
Authors: DEBNATH UJJAL , CHAKRABORTY SUBENOY
Published: June 2003

We investigate the end state of the gravitational collapse of an inhomogeneous dust cloud in higher dimensional spacetime. The naked singularities are shown to be developing as the final outcome of non-marginally bound collapse. The naked singularities are found to be gravitationally strong in the sense of Tipler.
NEW SOLVABLE PSEUDO-HERMITIAN POTENTIAL MODELS WITH REAL SPECTRA
Authors: JIA CHUN-SHENG , YI LIANG-ZHONG , SUN YU , LIU JIAN-YI , SUN LIANG-TIAN
Published: June 2003

We construct three new solvable pseudo-Hermitian potential models with real spectra starting from the five-parameter exponential-type potential model.
CHASING THE GZK WITH HiRes
Authors: BERGMAN DOUGLAS R.
Published: June 2003

The HiRes collaboration has recently announced preliminary measurements of the energy spectrum of ultra-high energy cosmic rays (UHECR), as seen in monocular analyses from each of the two HiRes sites. This spectrum is consistent with the existence of the GZK cutoff, as well other aspects of the energy loss processes that cause the GZK cutoff. Based on the analytic energy loss formalism of Berezinsky et al., the HiRes spectra favor a distribution of extragalactic sources that has a similar distribution to that of luminous matter in the universe, both in its local over-density and in its cosmological evolution.
QUANTUM HAMILTONIANS AND PRIME NUMBERS
Authors: ROSU HARET C.
Published: June 2003

A short review of Schrödinger Hamiltonians for which the spectral problem has been related in the literature to the distribution of the prime numbers is presented here. We notice a possible connection between prime numbers and centrifugal inversions in black holes and suggest that this remarkable link could be directly studied within trapped Bose–Einstein condensates. In addition, when referring to the factorizing operators of Pitkanen and Castro and collaborators, we perform a mathematical extension allowing a more standard supersymmetric approach.
INFLATIONARY DILATONIC de SITTER UNIVERSE FROM ${\mathcal N} = 4$ SUPER-YANG–MILLS THEORY PERTURBED BY SCALARS
Authors: HURTADO JOHN QUIROGA
Published: June 2003

In this paper a quantum [Formula: see text] super-Yang–Mills theory perturbed by dilaton-coupled scalars, is considered. The induced effective action for such a theory is calculated on a dilaton-gravitational background using the conformal anomaly found via AdS/CFT correspondence. Considering such an effective action (using the large N method) as a quantum correction to the classical gravity action with cosmological constant we study the effect from dilaton to the scale factor (which corresponds to the inflationary universe without dilaton). It is shown that, depending on the initial conditions for the dilaton, the dilaton may slow down, or accelerate, the inflation process. At late times, the dilaton is decaying exponentially. At the end of this work, we consider the question how the perturbation of the solution for the scale factor affects the stability of the solution for the equations of motion and therefore the stability of the Inflationary Universe, which could be eternal.
DOES THE "KNEE" IN PRIMARY COSMIC RAY SPECTRUM EXIST?
Authors: STENKIN YURI V.
Published: June 2003

The problem of the knee in primary cosmic ray at energy about 3–5 PeV is the most exciting problem in cosmic ray physics. Since 1958, physicists have been trying to solve this problem. In our opinion, the problem could be solved from the experimental point of view, whereas the primary spectrum would follow a pure power law. A key to the "knee" problem lies in the hadronic structure of EAS and its propagation in the Earth's atmosphere. Neither exotic processes nor new physics are used. An explanation of the approach and some results of Monte Carlo simulations are given below.
ON THE β-FUNCTION AND CONFORMAL ANOMALY OF NONCOMMUTATIVE QED WITH ADJOINT MATTER FIELDS
Authors: SADOOGHI NÉDA , MOHAMMADI MOJTABA
Published: June 2003

In the first part of this work, a perturbative analysis up to one-loop order is carried out to determine the one-loop β-function of noncommutative U(1) gauge theory with matter fields in the adjoint representation. In the second part, the conformal anomaly of the same theory is calculated using Fujikawa's path integral method. The value of the one-loop β-function calculated in both methods coincides. As it turns out, noncommutative QED with matter fields in the adjoint representation is asymptotically free for the number of flavor degrees of freedom Nf < 3.
QUARK STRUCTURE OF HADRONS AND HIGH ENERGY COLLISIONS
Authors: NYIRI J.
Published: June 2003

The additive quark model is one of the simplest and oldest models for the description of soft processes at high energies, and it still works. We present here a review of this model and verify the rules of quark combinatorics following from it in hadronic Z0 decays.
BLACK HOLE ENTROPY INSIDE AND OUTSIDE THE BRICK WALL
Authors: LIU WENBIAO , HAN YIWEN , ZHOU ZHOU'AN
Published: June 2003

Applying the generalized uncertainty relation to the calculation of the free energy and entropy of a black hole inside the brick wall, the entropy proportional to the horizon area is derived from the contribution of the vicinity of the horizon. This is compared with the entropy calculated via the original brick wall model. The entropy given by the original brick wall model comes from the outside of the brick wall seemingly. The inside result using generalized uncertainty relation is similar to the outside result using original uncertainty relation, and the divergence inside the brick wall disappears. It is apparent that the cutoff is something related to the quantum theory of gravity.
MAGNETIC MONOPOLES AND CHIRAL ASYMMETRY
Authors: MARQUES G. C. , SPEHLER D.
Published: June 2003

The asymmetry, between electric (E) and magnetic (H) fields of Maxwell's equation is here analyzed by using the concept of chirality. The chiral spinorial approach sets the stage for the construction of a more general theory of spin-1 particles than usual electrodynamics. Chiral components of a rank-2 spinor field are taken as the dynamic variables of the theory. A rank-2 spinor accommodates another particle (the magnetic photon). This new particle emerges naturally from chiral invariance arguments. The nonexistence, in nature, of such a particle is the reason for the nonexistence of monopoles and the asymmetry in Maxwell's equation. The existence of magnetic monopoles would restore the symmetry of Maxwell's equation. We establish, in this way, at a very formal level, the connection between magnetic monopoles and chiral asymmetry.
CHIRAL FERMION OPERATORS ON THE LATTICE
Authors: KERLER WERNER
Published: June 2003

We only require generalized chiral symmetry and γ5-hermiticity, which leads to a large class of Dirac operators describing massless fermions on the lattice, and use this framework to give an overview of developments in this field. Spectral representations turn out to be a powerful tool for obtaining detailed properties of the operators and a general construction of them. A basic unitary operator is seen to play a central rôle in this context. We discuss a number of special cases of the operators and elaborate on various aspects of index relations. We also show that our weaker conditions lead still properly to Weyl fermions and to chiral gauge theories.
DISCRETE SPECTRA OF SEMIRELATIVISTIC HAMILTONIANS
Authors: HALL RICHARD L. , LUCHA WOLFGANG , SCHÖBERL FRANZ F.
Published: June 2003

We review various attempts to localize the discrete spectra of semirelativistic Hamiltonians of the form [Formula: see text] (defined, without loss of generality but for definiteness, in three spatial dimensions) as entering, for instance, in the spinless Salpeter equation; every Hamiltonian in this class of operators consists of the relativistic kinetic energy [Formula: see text], where β > 0 allows for the possibility of more than one particles of mass m, and a spherically symmetric attractive potential V(r), r ≡ |x|. In general, accurate eigenvalues of a nonlocal Hamiltonian operator can only be found by the use of a numerical approximation procedure. Our main emphasis, however, is on the derivation of rigorous semianalytical expressions for both upper and lower bounds to the energy levels of such operators. We compare the bounds obtained within different approaches and present relationships existing between the bounds.
ON THE SCALING OF INCLUSIVE SPECTRA OF SECONDARY PIONS IN THE FORWARD REGION
Authors: BHADRA A. , KUNWAR B.
Published: June 2003

Using available collider data the Feynman scaling on inclusive spectra of secondary pions is critically examined in the forward and very forward region incorporating the seagull effect. It is found that scaling holds to 10–15% in the forward region at least up to the center-of-mass energy 900 GeV. It is further observed that the Wdowczyk–Wolfendale scale breaking model is satisfied in the forward region only when inelasticity into pions decreases with energy.
JOINING-SPLITTING INTERACTION OF NONCRITICAL STRING
Authors: HADASZ LESZEK , JASKÓLSKI ZBIGNIEW
Published: June 2003

The joining-splitting interaction of noncritical bosonic string is analyzed in the light-cone formulation. The Mandelstam method of constructing tree string amplitudes is extended to the bosonic massive string models of the discrete series. The general properties of the Liouville longitudinal excitations which are necessary and sufficient for the Lorentz covariance of the light-cone amplitudes are derived. The results suggest that the covariant and the light-cone approach are equivalent also in the noncritical dimensions. Some aspects of unitarity of interacting noncritical massive string theory are discussed.
WARPED BRANE-WORLD COMPACTIFICATION WITH GAUSS–BONNET TERM
Authors: CHO Y. M. , NEUPANE I. P.
Published: June 2003

In the Randall–Sundrum (RS) brane-world model a singular delta-function source is matched by the second derivative of the warp factor. So one should take possible curvature corrections in the effective action of the RS models in the Gauss–Bonnet (GB) form. We present a linearized treatment of gravity in the RS brane-world with the Gauss–Bonnet modifications to Einstein gravity. We give explicit expressions for the Neumann propagator in arbitrary D dimensions and show that a bulk GB term gives, along with a tower of Kaluza–Klein modes in the bulk, a massless graviton on the brane, as in the standard RS model. Moreover, a nontrivial GB coupling can allow a new branch of solutions with finite Planck scale and no naked bulk singularity, which might be useful to avoid some of the previously known "no-go theorems" for RS brane-world compactifications.
CHERN–SIMONS GAUGE THEORY COUPLED WITH BF THEORY
Authors: IKEDA NORIAKI
Published: June 2003

We couple three-dimensional Chern–Simons gauge theory with BF theory and study deformations of the theory by means of the antifield BRST formalism. We analyze all possible consistent interaction terms for the action under physical requirements and find a new topological field theory in three dimensions with new nontrivial terms and a nontrivial gauge symmetry. We analyze the gauge symmetry of the theory and point out the theory that has the gauge symmetry based on the Courant algebroid.
THERMAL PROPERTIES OF NONDEGENERATE RELATIVISTIC QUANTUM GASES
Authors: HOMORODEAN LAUREAN
Published: June 2003

We present characteristic functions, thermal equation of state and heat capacity at constant volume for nondegenerate relativistic quantum gases without and with generation and annihilation of particle-antiparticle pairs. For some physical quantities, nonrelativistic and ultrarelativistic expressions are analysed.
STABILITY OF AN EXCITON BOUND TO AN IONIZED ACCEPTOR IN QUANTUM DOTS
Authors: BASKOUTAS S. , TERZIS A. F. , POLITIS C.
Published: June 2003

Binding energy for an exciton (X) bound in a parabolic two-dimensional quantum dot by an acceptor impurity A- located on the z-axis at a distance d from the dot plane, are calculated using the Hartree formalism with a recently developed numerical method (PMM) for the solution of the Schrödinger equation. As our analysis indicates there is a critical dot radius Rc such that for R < Rc the complex (A-, X) is unstable and with an increase of the impurity distance this critical radius increases. Furthermore, there is a critical value σc of the mass ratio [Formula: see text] such that for σ > σc the complex is stable.
SURFACE INDUCED ANOMALOUS SUPERCONDUCTIVITY
Authors: FINK HERMAN J. , HALEY STEPHEN B.
Published: June 2003

The Ginzburg–Landau (GL) theory is recast using a Hamiltonian involving the complete kinetic energy density which requires that the surface energy must contain a term ∇|ψ|2 to support superconducting (SC) states. The GL equations contain two temperature t dependent parameters α(t) and β(t), which are respectively the coefficients of the SC pair density ∝|ψ|2, and the pair interaction term ∝|ψ|4 in the free energy density. The sign of these parameters, which defines distinct solution classes, and the ratio [Formula: see text] are governed by the characteristics of the surface energy density. In addition to the conventional bulk superconducting states with (α < 0, β > 0), anomalous superconducting states exist for all other sign combinations, including cases with β < 0 which may exist only when surface pair interactions are significant. All possible solutions of our generalized nonlinear, one-dimensional GL equations are found analytically and applied to a thin superconducting slab which manifests the possibility of states exhibiting enhanced, diminished, and pre-wetting superconductivity. Critical currents are determined as functions of s(t) and surface parameters. The results are applied to critical current experiments on SNS systems.
SELF-TRAPPING IN AN ASYMMETRIC TWO-SITE HOLSTEIN MODEL
Authors: BUSTAMANTE C. A. , MOLINA M. I.
Published: June 2003

We examine numerically the long-time average probability in a two-site system, for finding an electron staying at an initially occupied site for an asymmetric quantum Holstein electron-phonon coupled model. The principal finding is the existence of quantum-mechanical resonant tunnelling channels in the electron localization phenomenon. Based on a strong-coupling perturbative analysis, we have explained the presence of the channels as a consequence of a general resonant effect on an effective two-level system. Finally, a comparison of the quantum problem with the semiclassical description given by the Discrete Nonlinear Schrödinger equation is performed.
X-RAY PROPAGATION IN TAPERED PLANAR WAVEGUIDE
Authors: DOLOCAN ANDREI , FRISO VAN DER VEEN J.
Published: June 2003

The present paper focuses on the tapered planar waveguide solution for an initial given wave form. The algorithm is constructed in distributions space such that the calculations can be actually computed by taking some hypothesis regarding the mode series which appear. The whole argument leads to the conclusion that the wave is compressed towards the waveguide in the direction of tilting, leading thereafter to a focusing phenomena. We present two alternative constructions in order to compute the convolution which gives the wave inside the waveguide. The hypothesis are providing results in good approximation with the real evolution of the field within the definition domain.
TWO-LEVEL TUNNELLING MODEL DESCRIPTION OF THERMAL CONDUCTIVITY FOR CuxSn1-x METALLIC GLASSES AT LOW TEMPERATURE
Authors: BHUIYAN G. M. , SHAHJAHAN MD. , ALI ISSAM , RAHMAN S. M. MUJIBUR
Published: June 2003

The two level tunnelling model is applied to analyze recent experimental data on low temperature thermal conductivity of Cu x Sn 1-x metallic glasses. An extra scattering mechanism due to Rayleigh is introduced to describe three characteristic regions of conductivity. Model parameters are determined using least-squares fitting procedure. Results derived from the parameters allow one to predict several interesting low temperature properties of metallic glasses in particular the characteristic plateau of conductivity. Theoretical results are also compared and contrasted with those of other metallic and non-metallic systems, and both common and uncommon features that exist between them are discussed.
Phase State as a Cooper-Pair Number: Phase Minimum Uncertainty State for Josephson Junction
Authors: Fan Hong-Yi
Published: July 2003

Based on Feynman's explanation that a Cooper pair is "a bound pair act as a Bose particle", we propose a bosonic phase operator formalism and a bosonic Hamiltonian model for Josephson junction. The Cooper pair number — phase uncertainty relation is thus established. The corresponding minimum uncertainty state is derived which turns out to be a phase state.
Energy Concentration for Thin Films in Micromagnetics
Authors: Moser Roger
Published: July 2003

We consider variational equations from micromagnetics for thin films of ferromagnetic materials and study solutions as the thickness of the film tends to 0. We find a behavior which is similar to that of sequences of harmonic maps in two dimensions.
Mumford–Shah Functional as Γ-Limit of Discrete Perona–Malik Energies
Authors: Morini M. , Negri M.
Published: July 2003

We prove that a suitable rescaling of biased Perona–Malik energies, defined in the discrete setting, Γ-converges to an anisotropic version of the Mumford–Shah functional. Numerical results are discussed.
Periodic Solutions for a Class of Functional Differential Equations with State-Dependent Delay Close to Zero
Authors: Ouifki R. , Hbid M. L.
Published: July 2003

The purpose of the paper is to prove the existence of periodic solutions for a functional differential equation with state-dependent delay, of the type [Formula: see text] Transforming this equation into a perturbed constant delay equation and using the Hopf bifurcation result and the Poincaré procedure for this last equation, we prove the existence of a branch of periodic solutions for the state-dependent delay equation, bifurcating from r ≡ 0.
On the Analysis of a Mathematical Model for Metal Matrix Composites Manufacturing
Authors: Farina A. , Fasano A.
Published: July 2003

We prove the existence and uniqueness theorems for a free boundary problem formulated as a mathematical model for metal matrix composites manufacturing. The process consists of the injection of a liquid metal through a rigid porous solid, accompanied by partial solidification and subsequent remelting. A technologically relevant qualitative property here investigated is a condition ensuring that solidification does not proceed to a point that the molten metal flow is stopped before the complete filling of the mould.
On Well-Posedness of a Boltzmann-Like Semiconductor Model
Authors: Banasiak Jacek
Published: July 2003

The paper deals with an analysis of well-posedness of the Boltzmann-like semiconductor equation with unbounded collision frequency, introduced recently by Majorana and Milazzo.17 The equation is derived by writing the balance of the electrons lost and gained at each energy level due to scattering on the crystalline lattice of the semiconductor. As the total amount of electrons is expected to be constant, the process can be viewed as a Markov process, and from the functional analytic point of view it fits into the general theory of substochastic semigroups.5,26 In this paper we present two methods of solving the evolution equation describing this process: one is a generalization of the approach of Reuter and Ledermann23 to solving differential equations governing Markov processes with denumerably many states, while the other is based on the Kato–Voigt perturbation technique for substochastic semigroups.15,26,2,3,5 The combination of these two techniques is a powerful tool yielding strong results on the existence and uniqueness of conservative solutions. It is also shown how the solution method employed in Ref. 17 fits into the theory developed in this paper.
Fluid-Magnetic Splitting of the Magnetohydrodynamic Equations
Authors: Popa Cătălin , Sritharan S. S.
Published: July 2003

We consider a splitting approximation of the magnetohydrodynamic equations which consists of decoupling the Navier–Stokes and Maxwell equations which form the magnetohydrodynamic system, on small time intervals. To compute the approximate solutions we start with a pair of initial velocity and magnetic fields and alternately solve Navier–Stokes and dynamo equations. The main result of the paper states that for sufficiently smooth initial data, the proposed scheme converges in Lp norm with p > 3. Besides the applications in numerical analysis, this scheme can also be a valuable tool in understanding the physical and mathematical structure of the magnetohydrodynamic equations.
Thermodynamics of Nonlocal Electromagnetism and Superconductivity
Authors: Fabrizio M. , Lazzari B. , Morro A.
Published: July 2003

This paper provides a thermodynamic theory, of electromagnetic undeformable media, which incorporates nonlocal effects. The laws of thermodynamics are taken to keep their standard form when applied to a whole body. If a sub-body is involved, then an additional term is allowed which accounts for possible fluxes of energy and entropy due to exchanges between the sub-body and the remaining part of the body. The divergence of such fluxes plays the role of localization residual. Next superconductivity is framed within the nonlocal theory. The nondissipativity of the theory follows without requiring any ad hoc condition. Also, the Ginzburg–Landau theory is considered as a model of phase transition. The pertinent equations are shown to be given by a free energy function of the magnetic field and of the modulus of a standard complex parameter. This approach has the advantage that the theory is apparently gauge-invariant. Further, as a generalization, the theory for time-dependent fields is elaborated.
Strict Minimality of Alternating Knots in S × I
Authors: Fleming T.
Published: July 2003

For prime knots that lie in the plane, it is known that a reduced alternating projection of a knot has fewer crossings than any non-alternating projection of that knot. We show a similar result for knots that lie in S × I, where S is a surface. A combination of polynomial, geometric and topological techniques are used.
Computations of Turaev-Viro-Ocneanu Invariants of 3-Manifolds from Subfactors
Authors: Sato Nobuya , Wakui Michihisa
Published: July 2003

In this paper, we establish a rigorous correspondence between the two tube algebras, that one comes from the Turaev-Viro-Ocneanu TQFT introduced by Ocneanu and another comes from the sector theory introduced by Izumi, and construct a canonical isomorphism between the centers of the two tube algebras, which is a conjugate linear isomorphism preserving the products of the two algebras and commuting with the actions of SL(2, Z). Via this correspondence and the Dehn surgery formula, we compute Turaev-Viro-Ocneanu invariants from several subfactors for basic 3-manifolds including lens spaces and Brieskorn 3-manifolds by using Izumi's data written in terms of sectors.
X-Ray Photoelectron Spectroscopic Study of the Surface Reaction of Uranium–Niobium Alloy with O2
Authors: Fu Xiaoguo , Liu Kezhao , Wang Xiaolin , Zhao Zhengping , Yu Yong
Published: July 2003

The initial oxidation of uranium–niobium alloy in oxygen atmosphere at 298 K has been studied by X-ray photoelectron spectroscopy (XPS). For comparison, the adsorption of oxygen on pure metal niobium and uranium has also been studied. The changes of U4f, Nb3d and O1s spectra during in situ oxidation indicate that the adsorption of oxygen on uranium–niobium alloy surfaces first leads to the formation of UO2 and NbO; then NbO2 and Nb2O5 are detected with increasing exposures of oxygen. The segregations of U and Nb to the uranium–niobium alloy surfaces are observed at different oxidation stages. The oxide film formation of uranium–niobium alloy is faster than that of pure uranium at initial oxidation stages.
Crystal Truncation Rod Measurements from Buried Quantum Dots
Authors: Rawle J. L. , Howes P. B. , Alcock S. G.
Published: July 2003

We present a method of modelling the X-ray diffraction (XRD) from buried quantum dots (QDs). Both diffuse scattering and crystal truncation rods can be modelled by calculating the scattering atomistically and adding a contribution from the bulk crystal. Because there are a large number of atoms, their positions cannot be fitted independently and Keating energy minimisation is used to ensure that the strain is physically realistic. Calculated scattering is compared with experimental data, and some of the challenges presented by real QDs are considered.
Photothermal Sorption of Gases in Porous Glass
Authors: Dmytruk Andriy , Jin Tetsuro , Lin Hong , Yazawa Tetsuo
Published: July 2003

Gas permeability of CO2, N2 and He gases through a porous glass membrane of 3.5 nm pore diameter was investigated experimentally. Changes of the gas flow rate under Xe-lamp irradiation have been found. The observed phenomenon is explained by photothermal sorption. Estimation of gas permeability has been carried out. Experimental data of the induced gas permeability are in agreement with the theoretical estimation. A new method for gas separation by time modulation of the membrane temperature is proposed in which temperature modulation occurs by periodical heating of the membrane by the irradiation.
Adsorbed Structures of Ba on Si(110) Surfaces Studied by LEED and STM
Authors: Sakamoto Y. , Fukui Y. , Takeuchi J. , Hongo S. , Urano T. , Yoshimura M.
Published: July 2003

Adsorbed structures of barium on Si(110) surfaces have been studied by low energy electron diffraction (LEED) and scanning tunneling microscopy (STM). Several structures of "10 × 1," "12 × 2," 11 × 6 and streaky 4 × n were observed by LEED at annealing temperatures of about 775°C, 800°C, 900°C and 1100°C, respectively, after a-few-monolayer deposition of Ba at room temperature. In the STM experiment periodic structures of "10 × 6" and 11 × 6, and a rearrangement of pentagon pairs which is the unit structure seen on the terrace for the clean Si(110) "16 × 2" surface, were observed.
High-Resolution X-Ray Diffractometry Investigation of Interface Layers in GaN/AlN Structures Grown on Sapphire Substrates
Authors: Mudie Stephen , Pavlov Konstantin , Morgan Michael , Tabuchi Masao , Takeda Yoshikazu , Hester James
Published: July 2003

GaInN is an important wide band gap material with applications in short wavelength optoelectronic devices. The GaInN layer is often grown on a sapphire substrate, with low-temperature-deposited AlN and thick GaN used as buffer layers. The growth regime consists of many steps, each of which contributes to the overall properties of the device. The aim of our high-resolution X-ray diffraction experiments, conducted at the Photon Factory (Tsukuba, Japan), was to investigate the structural quality of the AlN buffer layer, which affects the final properties of the device. Reciprocal space mapping was used to study samples (having various layer thicknesses) from each stage of the growth process. Analysis of the experimental data provides parameters such as mosaic block dimensions and orientation, lattice strain distribution, and layer thickness.
Ion Beam Triangulation of Surfaces and Ultrathin Films
Authors: Pfandzelter R. , Bernhard T. , Winter H.
Published: July 2003

Ion beam triangulation is a real space technique to probe structures of surfaces and ultrathin films. In-plane arrangement of surface atoms is provided from enhanced kinetic electron emission yields for the transition from planar to axial surface channeling. The technique is applied to clean (001) surfaces of fcc Cu and bcc Fe as well as ultrathin films of Mn and Co, epitaxially grown on these surfaces at different temperatures.