bluuebunny/crossref_metadata_2025 huggingface dataset:
A SURVEY OF VETERINARY RADIATION FACILITIES IN THE UNITED STATES DURING 2001
Authors: McEntee Margaret C.
Published: September 2004

A survey of veterinary radiation therapy facilities in the United States was done in 2001 to determine the type of equipment available, radiation protocols used, case load, tumor types irradiated, as well as other details of the practice of radiation oncology. A total of 42 sites were identified and included 17 (40%) academic institutions, and 25 (60%) private practice external beam radiation facilities. The overall response rate was 79% (33/42 responded). Based on this survey there is substantial variation between facilities in all aspects ranging from equipment and personnel to radiation protocols and caseloads. American College of Veterinary Radiology boarded radiation oncologists direct 76% of the radiation facilities at academic institutions and 60% of the private practice facilities. Three facilities had orthovoltage radiation units only, and 30 facilities had megavoltage equipment: cobalt 60 or linear accelerator. A total of 18 facilities had linear accelerators with three of these off site at a human radiation facility. Patient load information was available from 31 sites (74% of the radiation facilities in the United States), and based on the responses 2790 dogs and 1081 cats were irradiated in 2001. Canine mast cell tumors were the most frequently irradiated tumor. This represents the first survey of veterinary radiation facilities in the United States and provides information on the specialty of veterinary radiation oncology.
The opioid system in the gastrointestinal tract
Authors: Sternini C. , Patierno S. , Selmer I. ‐S. , Kirchgessner A.
Published: September 2004

µ‐, δ‐ and κ‐opioid receptors (ORs) mediate the effects of endogenous opioids and opiate drugs. Here we report (1) the distribution of µOR in the guinea‐pig and human gastrointestinal tract in relation to endogenous ligands, to functionally distinct structures in the gut and to δOR and κOR; and (2) the ligand‐induced µOR endocytosis in enteric neurones using in vitro and in vivo models. In the guinea pig, µOR immunoreactivity is confined mainly to the myenteric plexus. µOR myenteric neurones are most numerous in the small intestine, followed by the stomach and the proximal colon. µOR immunoreactive fibres are dense in the muscle layer and the deep muscular plexus, where they are in close association with interstitial cells of Cajal. This distribution closely matches the pattern of enkephalin. µOR enteric neurones comprise functionally distinct populations of neurones of the ascending and descending pathways of the peristaltic reflex. In human gut, µOR immunoreactivity is localized to myenteric and submucosal neurones and to immune cells of the lamina propria. δOR immunoreactivity is located in both plexuses where it is predominantly in varicose fibres in the plexuses, muscle and mucosa, whereas κOR immunoreactivity appears to be confined to the myenteric plexus and to bundles of fibres in the muscle. µOR undergoes endocytosis in a concentration‐dependent manner, in vitro and in vivo. Pronounced µOR endocytosis is observed in neurones from animals that underwent abdominal surgery that has been shown to induce delay in gastrointestinal transit. We can conclude that all three ORs are localized to the enteric nervous system with differences among species, and that µOR endocytosis can be utilized as a means to visualize enteric neurones activated by opioids and sites of opioid release.
Preclinical studies of opioids and opioid antagonists on gastrointestinal function
Authors: Greenwood‐Van Meerveld B. , Gardner C. J. , Little P. J. , Hicks G. A. , Dehaven‐Hudkins D. L.
Published: September 2004

Opioid receptors in the gastrointestinal (GI) tract mediate the effects of endogenous opioid peptides and exogenously administered opioid analgesics, on a variety of physiological functions associated with motility, secretion and visceral pain. The studies reviewed or reported here describe a range of in vivo activities of opioid receptor antagonists upon GI function in rodents, focusing on µ receptors. Naloxone, and the peripherally acting µ‐opioid receptor antagonists alvimopan and methylnaltrexone, reverse morphine‐induced inhibition of GI transit in mice and rats, and morphine‐ or loperamide‐induced inhibition of castor oil‐induced diarrhoea in mice. At doses producing maximal reversal of morphine‐induced effects upon GI transit, only the central nervous system (CNS) penetrant antagonist naloxone was able to reverse morphine‐induced analgesia. Both central and peripheral opioid antagonists may affect GI function and/or visceromotor sensitivity in the absence of exogenous opioid analgesics, suggesting a constitutive role for endogenous opioid peptides in the control of GI physiology. Furthermore, in contrast to naloxone, alvimopan does not produce hypersensitivity to the visceromotor response induced by nociceptive levels of colorectal distension in a rodent model of postinflammatory colonic hypersensitivity, suggesting that in the periphery endogenous μ‐opioid receptor‐mediated mechanisms do not regulate colonic sensitivity. The data support the hypothesis that peripherally acting opioid antagonists may be able to selectively block opioid receptors in the GI tract, thereby preserving normal GI physiology, while not blocking the effects of endogenous opioid peptides or exogenous opioid analgesics in the CNS. These findings suggest that the primary sites of action of µ‐opioid agonists with respect to inhibition of GI function are in the periphery, whereas analgesic activity resides primarily in the CNS.
Peripheral opiate action on afferent fibres supplying the rat intestine
Authors: Grundy D. , Booth C. E. , Winchester W. , Hicks G. A.
Published: September 2004

The aim of the present study was to examine the sensitivity of mesenteric afferents supplying the rat small intestine to µ‐opioid receptor ligands. Mesenteric afferent discharge was recorded electrophysiologically in response to [D‐ALA2, N‐Me‐Phe4, Gly5‐ol]‐enkephalin (DAMGO; 100 µg kg−1 i.v.), before and after treatment with the µ‐receptor antagonist alvimopan (1 mg kg−1 i.v.). DAMGO markedly stimulated whole nerve mesenteric afferent discharge (P < 0.05), an effect completely blocked by alvimopan. The response of mesenteric afferents to 2‐methyl‐5‐hydroxytryptamine (30 µg kg−1 i.v.), bradykinin (0.1–1 µg kg−1 i.a.) and both low‐ and high‐threshold distension (0–60 mmHg) was unaffected by alvimopan. In chronically vagotomized animals, the low‐threshold response to distension was attenuated while the remaining high‐threshold response was unaffected by alvimopan. In conclusion, mesenteric afferent fibres are markedly stimulated by µ‐opioid receptor agonists, an effect blocked by alvimopan, which may contribute to the gastrointestinal reflex and behavioural responses to opiate treatment or abuse. However, alvimopan did not influence the normal sensitivity of intestinal afferents to chemical and mechanical stimuli that activate different subpopulations of vagal and spinal afferents. Thus, alvimopan may be useful for the treatment of gastrointestinal sequelae following opiate treatment for postoperative or chronic pain.
Mechanisms of postoperative ileus
Authors: Bauer A. J. , Boeckxstaens G. E.
Published: September 2004

Postoperative ileus is an iatrogenic condition that follows abdominal surgery. Three main mechanisms are involved in its causation, namely neurogenic, inflammatory and pharmacological mechanisms. In the acute postoperative phase, mainly spinal and supraspinal adrenergic and non‐adrenergic pathways are activated. Recent studies, however, show that the prolonged phase of postoperative ileus is caused by an enteric molecular inflammatory response and the subsequent recruitment of leucocytes into the muscularis of the intestinal segments manipulated during surgery. This inflammation impairs local neuromuscular function and activates neurogenic inhibitory pathways, inhibiting motility of the entire gastrointestinal tract. The mechanisms underlying the recruitment of the inflammatory cells, and their interaction with the intestinal afferent innervation, are discussed. Finally, opioids administered for postoperative pain control also contribute to a large extent to the reduction in propulsive gastrointestinal motility observed after abdominal surgery.
Clinical perspective on postoperative ileus and the effect of opiates
Authors: Delaney C. P.
Published: September 2004

Postoperative ileus (POI) is a mandatory period of cessation of intestinal function, after abdominal surgery. Over the last decade research has continued into this field, and while we continue to learn about pathogenesis, few controlled data are available for management. The clinical manifestations of POI are reviewed. Management techniques are also reviewed, including the use of postoperative care plans with early ambulation and diet, the effects of epidural anaesthesia, benefits of laparoscopic approaches for intestinal resection, and potential avenues for prevention using novel medications.
Advanced High Turning Compressor Airfoils for Low Reynolds Number Condition—Part I: Design and Optimization
Authors: Sonoda Toyotaka , Yamaguchi Yoshihiro , Arima Toshiyuki , Olhofer Markus , Sendhoff Bernhard , Schreiber Heinz-Adolf
Published: September 2004

High performance compressor airfoils at a low Reynolds number condition at Re=1.3×105 have been developed using evolutionary algorithms in order to improve the performance of the outlet guide vane (OGV), used in a single low pressure turbine (LPT) of a small turbofan engine for business jet aircrafts. Two different numerical optimization methods, the evolution strategy (ES) and the multi-objective genetic algorithm (MOGA), were adopted for the design process to minimize the total pressure loss and the deviation angle at the design point at low Reynolds number condition. Especially, with respect to the MOGA, robustness against changes of the incidence angle is considered. The optimization process includes the representation of the blade geometry, the generation of a numerical grid and a blade-to-blade analysis using a quasi-three-dimensional Navier-Stokes solver with a k-ω turbulence model including a newly implemented transition model to evaluate the performance. Overall aerodynamic performance and boundary layer properties for the two optimized blades are discussed numerically. The superior performance of the two optimized airfoils is demonstrated by a comparison with conventional controlled diffusion airfoils (CDA). The advantage in performance has been confirmed by detailed experimental investigations, which are presented in Part II of this paper.
Experimental Surface Heat Transfer and Flow Structure in a Curved Channel With Laminar, Transitional, and Turbulent Flows
Authors: Ligrani P. M. , Hedlund C. R.
Published: September 2004

Heat transfer and flow structure are described in a channel with a straight portion followed by a portion with mild curvature at Dean numbers from 100 to 1084. The channel aspect ratio is 40, radius ratio is 0.979, and the ratio of shear layer thickness to channel inner radius is 0.011. The data presented include flow visualizations, and spanwise-averaged Nusselt numbers. Also included are time-averaged turbulence structural data, time-averaged profiles of streamwise velocity, spectra of longitudinal velocity fluctuations, and a survey of the radial time-averaged vorticity component. Different flow events are observed including laminar two-dimensional flow, Dean vortex flow, wavy Dean vortex flow (in both undulating and twisting modes), splitting and merging of Dean vortex pairs, transitional flow with arrays of Dean vortex pairs, and fully turbulent flow with arrays of Dean vortex pairs. Transitional events generally first appear in the curved portion of the channel at Dean numbers less than 350 in the form of arrays of counterrotating Dean vortex pairs. At Dean numbers greater than 350, transitional events occur in the upstream straight portion of the channel but then continue to cause important variations in the downstream curved portion. The resulting Nusselt number variations with curvature, streamwise development, and Dean number are described as they are affected by these different laminar, transitional, and turbulent flow phenomena.
The Effect of Real Turbine Roughness With Pressure Gradient on Heat Transfer
Authors: Bons Jeffrey P. , McClain Stephen T.
Published: September 2004

Experimental measurements of heat transfer (St) are reported for low speed flow over scaled turbine roughness models at three different freestream pressure gradients: adverse, zero (nominally), and favorable. The roughness models were scaled from surface measurements taken on actual, in-service land-based turbine hardware and include samples of fuel deposits, TBC spallation, erosion, and pitting as well as a smooth control surface. All St measurements were made in a developing turbulent boundary layer at the same value of Reynolds number Rex≅900,000. An integral boundary layer method used to estimate cf for the smooth wall cases allowed the calculation of the Reynolds analogy 2St/cf. Results indicate that for a smooth wall, Reynolds analogy varies appreciably with pressure gradient. Smooth surface heat transfer is considerably less sensitive to pressure gradients than skin friction. For the rough surfaces with adverse pressure gradient, St is less sensitive to roughness than with zero or favorable pressure gradient. Roughness-induced Stanton number increases at zero pressure gradient range from 16–44% (depending on roughness type), while increases with adverse pressure gradient are 7% less on average for the same roughness type. Hot-wire measurements show a corresponding drop in roughness-induced momentum deficit and streamwise turbulent kinetic energy generation in the adverse pressure gradient boundary layer compared with the other pressure gradient conditions. The combined effects of roughness and pressure gradient are different than their individual effects added together. Specifically, for adverse pressure gradient the combined effect on heat transfer is 9% less than that estimated by adding their separate effects. For favorable pressure gradient, the additive estimate is 6% lower than the result with combined effects. Identical measurements on a “simulated” roughness surface composed of cones in an ordered array show a behavior unlike that of the scaled “real” roughness models. St calculations made using a discrete-element roughness model show promising agreement with the experimental data. Predictions and data combine to underline the importance of accounting for pressure gradient and surface roughness effects simultaneously rather than independently for accurate performance calculations in turbines.
Experimental Investigation of Unsteady Flow Field in the Tip Region of an Axial Compressor Rotor Passage at Near Stall Condition With Stereoscopic Particle Image Velocimetry
Authors: Liu Baojie , Wang Hongwei , Liu Huoxing , Yu Hongjun , Jiang Haokang , Chen Maozhang
Published: September 2004

Stereoscopic particle image velocimetry (SPIV) was applied to a large-scale low-speed compressor facility with the configuration of the two CCD cameras placed on each side of the light sheet to make the measurement of the vortices in the cross flow section possible and to avoid the disturbance from the light sheet containing periscope-type probe. Instantaneous velocity and vorticity distributions were successfully documented at the tip region of the rotor at near stall condition. The measurement results clearly revealed the generation and evolution of the tip leakage vortex. Comparing to design condition, the tip leakage vortex at near stall condition generates and breaks down earlier and interacts more violently with mainstream, which causes large blockage and much loss. Whether corner vortex exists or not is the primary difference between near stall and design condition. Differing from the leakage vortex, the corner vortex is composed of multiple vortices developed from the suction surface of the rotor blade. The key mechanism for the generation of the corner vortex is that the rotation of the rotor has different effect on the evolution of positive vortices and negative vortices, which makes the positive vortices dissipates faster than the negative ones, the vortices at the rotor exit therefore bear mainly negative vortices, which induces the fluids to rotate clockwise at the corner and forms the corner vortex.
Acoustic Resonance in Aeroengine Intake Ducts
Authors: Cooper A. J. , Parry A. B. , Peake N.
Published: September 2004

A theoretical model is used to investigate the effect of geometry, flow conditions and acoustic lining on the occurrence of acoustic resonance within aeroengine ducts. Semi-analytical methods are used to demonstrate that two types of acoustic resonance can be excited. The first is an intake resonance arising due to axial variation of the intake shape and the presence of swirling flow downstream of the rotor. The second occurs as a result of mode trapping between the rotor and stator. Such resonance phenomena may be relevant to the destabilization of the fan and the onset of flutter and rotating stall.
Probiotics and human health: a clinical perspective
Authors: Gill H S , Guarner F
Published: September 2004

There is unequivocal evidence that administration of probiotics could be effective in the treatment of acute infectious diarrhoea in children and the prevention of antibiotic associated diarrhoea and nosocomial/community acquired diarrhoea. Encouraging evidence is also emerging for the effectiveness of probiotics in the prevention and management of pouchitis and paediatric atopic diseases, and the prevention of postoperative infections. There is also strong evidence that certain probiotic strains are able to enhance immune function, especially in subjects with less than adequate immune function such as the elderly. Efficacy of probiotics in the prevention of traveller’s diarrhoea, sepsis associated with severe acute pancreatitis, and cancers, the management of ulcerative colitis, and lowering of blood cholesterol remains unproven. In addition to firm evidence of efficacy (for a range of conditions), major gaps exist in our knowledge regarding the mechanisms by which probiotics modulate various physiological functions and the optimum dose, frequency, and duration of treatment for different probiotic strains.
Endocrine emergencies
Authors: Savage M W , Mah P M , Weetman A P , Newell-Price J
Published: September 2004

Diabetic and endocrine emergencies are traditionally treated by the acute medical admitting team or accident and emergency department staff. Most will see diabetic emergencies on a regular basis, as they are common and both type 1 and type 2 disease are increasing in prevalence. Diabetic emergencies are usually easily treated and the patients discharged. However, it is vital not to become complacent as these disorders can lead to death. It is particularly important to follow local guidance and to involve the diabetes team both during and after each episode. Recently it has become clear that about 30% of patients admitted with acute coronary syndrome (including infarction) have either diabetes or “stress hyperglycaemia”; evidence suggests that these patients should be treated not only as a cardiac emergency but also as a diabetic one. Thus, every patient with acute coronary syndrome or acute myocardial infarction needs diabetes to be excluded. The other endocrine emergencies are less common, but in some ways more important simply because of their rarity. A high level of suspicion is often required to make a diagnosis, although some, such as myxoedema coma, are usually obvious. Treatment must be started before the diagnosis can be confirmed. Guidance on making the diagnosis and initiating treatment should be made available on the local NHS intranet for non-endocrinologists to access; and where possible expert advice made available by telephone. The basic management steps in the common diabetic and endocrine emergencies are outlined; this is not a complete list, but rather an insight for those involved in non-selected emergency admissions.
Sentinel lymph node biopsy in breast cancer patients after overnight migration of radiolabelled sulphur colloid
Authors: Lamichhane N , Shen K W , Li C L , Han Q X , Zhang Y J , Shao Z M , Shen Z Z
Published: September 2004

Objective: To evaluate the performance and feasibility of sentinel lymph node biopsy in breast cancer patients using technetium-99m (99mTc) sulphur colloid and gamma probe.

Methods: From May 2000 to March 2001, 70 patients with a tumour less than 5 cm with clinically negative axillary lymph nodes underwent sentinel node biopsy followed by standard axillary dissection. 99mTc sulphur colloid was injected around the primary tumour the day before surgery and a gamma probe was used to detect the sentinel lymph node during the surgical procedure. Sentinel lymph node biopsy was compared with standard axillary dissection for its ability to accurately reflect the final pathological status of the axillary nodes.

Results: The sentinel lymph node was successfully identified in 67 of 70 patients (95.71%). The number of sentinel lymph nodes ranged from 1–5 (mean 1.5) and non-sentinel nodes ranged from 5–22 (mean 13.3). Of the 67 patients with successfully identified sentinel lymph nodes, 43.28% (29/67) were histologically positive. Sensitivity of the sentinel lymph node to predict axilla was 82.75%; specificity was 100%. Positive and negative predictive values were 100% and 88.3% respectively. The sentinel lymph node was falsely negative in five patients, yielding an accuracy of 92.53%. Sentinel lymph node biopsy was more accurate for T1 tumours than for T2 tumours.

Conclusions: The gamma probe guided method after overnight migration of 99mTc sulphur colloid is technically feasible for detecting sentinel lymph nodes in most breast cancer patients, accurately predicting the axillary lymph node status, and appears more accurate for T1 lesions than for larger lesions. This minimally invasive axillary staging procedure represents a major advance in the surgical treatment of breast cancer.
|Vub| AND |Vcb|, CHARM COUNTING AND LIFETIME DIFFERENCES IN INCLUSIVE BOTTOM HADRON DECAYS
Authors: WU Y. L. , YAN Y. A.
Published: September 2004

Inclusive bottom hadron decays are analyzed based on the heavy quark effective field theory (HQEFT). Special attentions in this paper are paid to the b→u transitions and nonspectator effects. As a consequence, the CKM quark mixing matrix elements |Vub| and |Vcb| are reliably extracted from the inclusive semileptonic decays B→Xueν and B→Xceν. Various observables, such as the semileptonic branch ratio BSL, the lifetime differences among B-, B0, Bsand Λbhadrons, the charm counting nc, are predicted and found to be consistent with the present experimental data.
NONLINEAR SCHRÖDINGER DYNAMICS OF MATRIX D-BRANES
Authors: MAVROMATOS NICK E. , SZABO RICHARD J.
Published: September 2004

We formulate an effective Schrödinger wave equation describing the quantum dynamics of a system of D0-branes by applying the Wilson renormalization group equation to the world sheet partition function of a deformed σ-model describing the system, which includes the quantum recoil due to the exchange of string states between the individual D-particles. We arrive at an effective Fokker–Planck equation for the probability density with diffusion coefficient determined by the total kinetic energy of the recoiling system. We use Galilean invariance of the system to show that there are three possible solutions of the associated nonlinear Schrödinger equation depending on the strength of the open string interactions among the D-particles. When the open string energies are small compared to the total kinetic energy of the system, the solutions are governed by freely-propagating solitary waves. When the string coupling constant reaches a dynamically determined critical value, the system is described by minimal uncertainty wavepackets which describe the smearing of the D-particle coordinates due to the distortion of the surrounding space–time from the string interactions. For strong string interactions, bound state solutions exist with effective mass determined by an energy-dependent shift of the static BPS mass of the D0-branes.
PLASMON INTERACTIONS IN THE QUARK–GLUON PLASMA
Authors: METAXAS D. , NAIR V. P.
Published: September 2004

We construct plasmon creation and annihilation operators for Yang–Mills theory at finite temperature. This provides a starting point for perturbation theory with resummation of hard thermal loops in a Hamiltonian framework.
NONLINEAR VACUUM PHENOMENA IN NONCOMMUTATIVE QED
Authors: ALVAREZ-GAUMÉ L. , BARBÓN J. L. F.
Published: September 2004

We show that the classic results of Schwinger on the exact propagation of particles in the background of constant field-strengths and plane waves can be readily extended to the case of nocommutative QED. It is shown that nonperturbative effects on constant backgrounds are the same as their commutative counterparts, provided the on-shell gauge-invariant dynamics are referred to a nonperturbatively related space–time frame.

For the case of the plane wave background, we find evidence of the effective extended nature of noncommutative particles, producing retarded and advanced effects in scattering. Besides the known "dipolar" character of noncommutative neutral particles, we find that charged particles are also effectively extended, but they behave instead as "half-dipoles."
CURVED D-BRANE GEOMETRY AND ZERO MODES
Authors: KAR SUPRIYA
Published: September 2004

We present a path integral formalism to review the effective dynamics of an arbitrary and curved Dirichlet p-brane (Dp-brane) in open bosonic string and subsequently in type I superstring theory. We obtain the perturbative corrections to the Dirac–Born–Infeld dynamics up to [Formula: see text] in the presence of an antisymmetric two-form B field. A part of the corrections can be seen to be associated with an ultraviolet divergence. Renormalization of the Dp-brane collective coordinates is performed to show that the residual corrections lead to a noncommutative description on the world volume. The Dp-brane modes are analyzed and we show that its zero modes play a vital role in noncommutative geometry. Our analysis facilitates the noncommutative world volume description for an arbitrary B field.
NONPERTURBATIVE DISPERSIVE SECTOR IN STRONG (QUASI-)ABELIAN FIELDS
Authors: CVETIČ G. , YU JI-YOUNG
Published: September 2004

In strong (quasi-)Abelian fields, even at the one-loop level of the coupling constant, quantum fluctuations of fermions induce an effective Lagrangian density whose imaginary (absorptive) part is purely nonperturbative and known to be responsible for the fermion–antifermion pair creation. On the other hand, the induced real (dispersive) part has perturbative and nonperturbative contributions. In the one-loop case, we argue how to separate the two contributions from each other for any strength of the field. We show numerically that the nonperturbative contributions are in general comparable with or larger than the induced perturbative ones. We arrive at qualitatively similar conclusions also for the induced energy density. Further, we investigate numerically the quasianalytic continuation of the perturbative results into the nonperturbative sector, by employing (modified) Borel–Padé. It turns out that in the case at hand, we have to integrate over renormalon singularities, but there is no renormalon ambiguity involved.
THE PROPERTIES OF A HADRON
Authors: BANERJEE S. N. , BHATTACHARYA A. , CHAKRABARTI B. , BANERJEE S.
Published: September 2004

Using the analogy of a well-known mathematical formalism, an analytical form of the probability density of a hadron as a quarkonium system has been suggested which corresponds to that obtained from the statistical model. The aforesaid prescription also offers the necessary framework to incorporate different orders of approximations in it. Unlike all existing theoretical approaches, the model reveals the fractal characteristics of a hadron, like the fractal dimension DF, correlation dimension DCand the anomalous dimension DA. The direct physical bearings of these dimensional quantities on the physical parameters related to the recent experimental data have also been discussed.
NUCLEAR MATTER IN INTENSE MAGNETIC FIELD AND WEAK PROCESSES
Authors: GOYAL ASHOK , GUPTA V. K. , GOSWAMI KANUPRIYA , TULI VINITA
Published: September 2004

We study the effect of magnetic field on the dominant neutrino emission processes in neutron stars. The processes are first calculated for the case when the magnetic field does not exceed the critical value to confine electrons to the lowest Landau state. We consider here magnetic fields up to ~1019 Gauss. We find that fields of strength 1015-1016 Gauss have significant effect on the neutronization process, for the direct URCA process the effect of the magnetic field becomes significant only at ~1019 Gauss. In order to estimate the effect we derive the composition of cold nuclear matter at high densities and in beta equilibrium, a situation appropriate for neutron stars. The hadronic interactions are incorporated through the exchange of scalar and vector mesons in the framework of relativistic mean field theory. In addition the effects of anomalous magnetic moments of nucleons are also considered.
TWO BODY NONLEPTONIC DECAYS OF Bs MESONS
Authors: KAUR HARPREET , KHANNA M. P.
Published: September 2004

Two-body nonleptonic decays of [Formula: see text] mesons involving heavy to heavy transitions are discussed in detail. All these decay widths are estimated by the use of spectator model dominance. The form factors for various transitions are calculated in BSW model improved to O(1/mQ) by comparison with the heavy quark effective theory.
A PEDESTRIAN APPROACH TO HIGH ENERGY LIMITS OF BRANES AND OTHER GRAVITATIONAL SYSTEMS
Authors: LINDSTRÖM ULF , SVENDSEN HARALD G.
Published: September 2004

In this article we study limits of models that contain a dimensionful parameter such as the mass of the relativistic point-particle. The limits are analogous to the massless limit of the particle and may be thought of as high energy limits. We present the ideas and work through several examples in a (hopefully) pedagogical manner. Along the way we derive several new results.
PATH INTEGRALS ON RIEMANNIAN MANIFOLDS WITH SYMMETRY AND INDUCED GAUGE STRUCTURE
Authors: TANIMURA SHOGO
Published: September 2004

We formulate path integrals on any Riemannian manifold which admits the action of a compact Lie group by isometric transformations. We consider a path integral on a Riemannian manifold M on which a Lie group G acts isometrically. Then we show that the path integral on M is reduced to a family of path integrals on a quotient space Q=M/G and that the reduced path integrals are completely classified by irreducible unitary representations of G. It is not necessary to assume that the action of G on M is either free or transitive. Hence our formulation is applicable to a wide class of manifolds, which includes inhomogeneous spaces, and it covers all the inequivalent quantizations. To describe the path integral on inhomogeneous space, stratification geometry, which is a generalization of the concept of principal fiber bundle, is necessarily introduced. Using it we show that the path integral is expressed as a product of three factors; the rotational energy amplitude, the vibrational energy amplitude, and the holonomy factor. When a singular point arises in Q, we determine the boundary condition of the path integral kernel for a path which runs through the singularity.
INFLUENCE OF STATISTICAL FLUCTUATIONS ON K/π RATIOS IN RELATIVISTIC HEAVY ION COLLISIONS
Authors: YANG C. B. , CAI X.
Published: September 2004

The influence of pure statistical fluctuations on K/π ratio is investigated in an event-by-event way. Poisson and the modified negative binomial distributions are used as the multiplicity distributions since they both have statistical background. It is shown that the distributions of the ratio in these cases are Gaussian, and the mean and relative variance are given analytically.
THE HIGGS SECTOR IN THE MINIMAL 3-3-1 MODEL WITH THE MOST GENERAL LEPTON-NUMBER CONSERVING POTENTIAL
Authors: ANH NGUYEN TUAN , KY NGUYEN ANH , LONG HOANG NGOC
Published: September 2004

The Higgs sector of the minimal 3-3-1 model with three triplets and one sextet is investigated in detail under the most general lepton-number conserving potential. The mass spectra and multiplet decomposition structure are explicitly given in a systematic order and a transparent way allowing them to be easily checked and used in further investigations. A previous problem that arose from the inconsistent signs of f2is also automatically solved.
PARAMETRIZING THE MIXING MATRIX: A UNIFIED APPROACH
Authors: CHATURVEDI S. , MUKUNDA N.
Published: September 2004

A unified approach to parametrization of the mixing matrix for N generations is developed. This approach not only has a clear geometrical underpinning but also has the advantage of being economical and recursive and leads in a natural way to the known phenomenologically useful parametrizations of the mixing matrix.
THE FUTURE OF PARTICLE PHYSICS
Authors: BJORKEN JAMES D.
Published: September 2004

After a very brief review of twentieth century elementary particle physics, prospects for the next century are discussed. First and most important are technological limits of opportunities; next, the future experimental program, and finally the status of the theory, in particular its limitations as well as its opportunities.
DUALITY PROPERTIES OF SUPER D-BRANE ACTIONS IN GENERAL TYPE IIB SUPERGRAVITY BACKGROUND
Authors: KIMURA TADAHIKO , ODA ICHIRO
Published: September 2004

We examine duality transformations of supersymmetric and κ-symmetric Dp-brane actions in a general type IIB supergravity background where in particular the dilaton and the axion are not supposed to be zero or a constant but a general superfield. Due to nonconstant dilaton and axion, we can explicitly show that the dilaton and the axion as well as the two two-form gauge potentials transform as doublets under the SL (2,R) transformation from the point of view of the world volume field theory.
COSMOLOGY OF BRANE-BULK MODELS IN FIVE DIMENSIONS
Authors: MOHAPATRA R. N. , DE S. PIRES C. A. , PÉREZ-LORENZANA A.
Published: September 2004

We study the cosmology of models with four space and one time dimension where our universe is a three-brane and report a few results which extend existing work in several directions. Assuming a stable fifth dimension, we obtain a solution for the metric, which does not depend on any arbitrary parameters. We discuss some implications of this result.
THE COSMOLOGICAL CONSTANT IN BRANE WORLD SCENARIOS AND STRING THEORY
Authors: DE ALWIS S. P.
Published: September 2004

The possibility of getting a zero (or small) cosmological constant within the brane world scenario is discussed in some detail. We find that the best one can do is to argue that within a certain class of compactifications (on squashed spheres) there may be a way of obtaining flat (or nearly flat) effective four dimensional theories by adjusting integration constants/parameters.
TOWARDS A SUPERSYMMETRIC NON-ABELIAN BORN-INFELD THEORY
Authors: BERGSHOEFF E. A. , DE ROO M. , SEVRIN A.
Published: September 2004

We define an iterative procedure to obtain a non-abelian generalization of the Born-Infeld action. This construction is made possible by the use of the severe restrictions imposed by kappa-symmetry. We have calculated all bosonic terms in the action up to terms quartic in the Yang-Mills field strength and all fermion bilinear terms up to terms cubic in the field strength. Already at this order the fermionic terms do not satisfy the symmetric trace-prescription.
VERTEX OPERATORS FOR AdS3 WITH RAMOND BACKGROUND
Authors: DOLAN LOUISE
Published: September 2004

The computation of exact vertex operators for the Type IIB superstring in an AdS3×S3 background with Ramond-Ramond flux is described. The components of these vertex operators are shown to satisfy the supergravity linearized equations of motion for the six-dimensional (2,0) theory of a supergravity and tensor multiplet expanded around AdS3×S3 spacetime.
D-BRANES IN THE BACKGROUND OF NS FIVEBRANES
Authors: ELITZUR SHMUEL , GIVEON AMIT , KUTASOV DAVID , RABINOVICI ELIEZER , SARKISSISAN GOR
Published: September 2004

We study the dynamics of D-branes in the near-horizon geometry of NS fivebranes. This leads to a holographically dual description of the physics of D-branes ending on and/or intersecting NS5-branes. We use it to verify some properties of such D-branes which were deduced indirectly in the past, and discuss some instabilities of non-supersymmetric brane configurations. Our construction also describes vacua of Little String Theory which are dual to open plus closed string theory in asymptotically linear dilaton spacetimes.
DOMAIN WALL WORLD(S)
Authors: CVETIČ M.
Published: September 2004

Gravitational properties of domain walls in fundamental theory and their implications for the trapping of gravity are reviewed. In particular, the difficulties to embed gravity trapping configurations within gauged supergravity is reviewed and the status of the domain walls obtained via the breathing mode of sphere reduced Type IIB supergravity is presented.
SOME COMMENTS ON BRANES, G-FLUX, AND K-THEORY
Authors: MOORE GREGORY
Published: September 2004

Summary of a talk explaining three ways in which string theory and M-theory are related to the mathematics of K-theory.
SPACE-TIME UNCERTAINTY AND NONCOMMUTATIVITY IN STRING THEORY
Authors: YONEYA TAMIAKI
Published: September 2004

We analyze the nature of space-time nonlocality in string theory. After giving a brief overview on the conjecture of the space-time uncertainty principle, a (semi-classical) reformulation of string quantum mechanics, in which the dynamics is represented by the noncommutativity between temporal and spatial coordinates, is outlined. The formalism is then compared to the space-time noncommutative field theories associated with nonzero electric B-fields.
NONABELIAN D-BRANES AND NONCOMMUTATIVE GEOMETRY
Authors: MYERS ROBERT
Published: September 2004

We discuss the nonabelian world-volume action which governs the dynamics of N coincident Dp-branes. In this theory, the branes' transverse displacements are described by matrix-valued scalar fields, and so this is a natural physical framework for the appearance of noncommutative geometry. One example is the dielectric effect by which Dp-branes may be polarized into a noncommutative geometry by external fields. Another example is the appearance of noncommutative geometries in the description of intersecting D-branes of differing dimensions, such as D-strings ending on a D3- or D5-brane.
STABLE NON-BPS STATES AND THEIR HOLOGRAPHIC DUALS
Authors: MUKHI SUNIL , SURYANARAYANA NEMANI V.
Published: September 2004

Stable non-BPS states can be constructed and studied in a variety of contexts in string theory. Here we review some interesting constructions that arise from suspended and wrapped branes. We also exhibit some stable non-BPS states that have holographic duals.
REPRESENTATIONS OF SUPERCONFORMAL ALGEBRAS IN THE AdS7/4/CFT6/3 CORRESPONDENCE
Authors: FERRARA SERGIO , SOKATCHEV EMERY
Published: September 2004

We perform a general analysis of representations of the superconformal algebras OSp (8/4, ℝ) and OSp (8*/2N) in harmonic superspace. We present a construction of their highest-weight UIR's by multiplication of the different types of massless conformal superfields ("supersingletons"). In particular, all "short multiplets" are classified. Representations undergoing shortening have "protected dimension" and may correspond to BPS states in the dual supergravity theory in anti-de Sitter space. These results are relevant for the classification of multitrace operators in boundary conformally invariant theories as well as for the classification of AdS black holes preserving different fractions of supersymmetry.
THE ENHANÇON, MULTIMONOPOLES AND FUZZY GEOMETRY
Authors: JOHNSON CLIFFORD V.
Published: September 2004

The presentation at Strings 2000 was intended to be in two main parts, but there was only time for part one. However both parts appeared on the online proceedings, and are also included in this document. The first part concerns an exploration of the connection between the physics of the "enhançon" geometry arising from wrapping N D6–branes on the K3 manifold in Type IIA string theory and that of a charge N BPS multi–monopole. This also relates to the physics of 2+1 dimensional SU(N) gauge theory with eight supercharges. The main results uncovered by this exploration are: a) better insight into the non–perturbative geometry of the enhançon; b) the structure of the moduli space geometry, and its characterisation in terms of a family of Atiyah–Hitchin–like manifolds; c) the use of Nahm data to describe aspects of the geometry, showing that the enhançon locus itself has a description as a fuzzy sphere. Part two discusses the addition of extra D2–branes into the geometry. Two probe computations show the difference between the geometry as seen by D2–branes and that seen by wrapped D6–branes, and the accompanying gauge theory interpretations are discussed.
TOP TEN PROBLEMS IN FUNDAMENTAL PHYSICS
Authors: DUFF M. J.
Published: September 2004

In 1900 the world-renowned mathematician David Hilbert presented twenty-three problems at the International Congress of Mathematicians in Paris. These problems have inspired mathematicians throughout the last century. As a piece of millennial madness, all participants of the Strings 2000 Conference were invited to help formulate the ten most important unsolved problems in fundamental physics. Each participant was allowed to submit one candidate problem for consideration. To qualify, the problem must not only have been important but also well-defined and stated in a clear way. The best ten problems were selected at the end of the conference by a selection panel consisting of David Gross, Edward Witten and myself.
START, STOP AND TRANSITION OF VELOCITIES OF AN UNDER-ACTUATED BIPEDAL ROBOT WITHOUT REFERENCE TRAJECTORIES
Authors: SABOURIN CHRISTOPHE , BRUNEAU OLIVIER , FONTAINE JEAN-GUY
Published: September 2004

In this paper, we propose a control strategy allowing us to perform the transition of velocities included in [0 m/s; 1 m/s] for the dynamic walking of a virtual under-actuated robot (RABBIT) without reference trajectories. This strategy of control enables us to carry out the transition from stop towards walking and the reverse process. The interest of this method is that, on the one hand, the intrinsic dynamics of the system are exploited by using a succession of active and passive phases and, on the other hand, the control strategy is very simple to implement on-line. Moreover, we apply this method by taking into account the technological limitations related to experimentation on the real robot such as dry and viscous frictions, maximum torque, and maximum power.
PERFORMANCE-DERIVED BEHAVIOR VOCABULARIES: DATA-DRIVEN ACQUISITION OF SKILLS FROM MOTION
Authors: JENKINS ODEST CHADWICKE , MATARIĆ MAJA J.
Published: September 2004

Control for and interaction with humanoid robots is often restrictive due to limitations of the robot platform and the high dimensionality of controlling systems with many degrees of freedom. We focus on the problem of providing a "skill-level interface" for a humanoid robot. Such an interface serves as (i) a modular foundation for structuring task-oriented control, (ii) a parsimonious abstraction of motor-level control (e.g. PD-servo control), and (iii) a means for grounding interactions between humans and robots through common skill vocabularies. Our approach to constructing skill-level interfaces is two-fold. First, we propose a representation for a skill-level interface as a "behavior vocabulary," a repertoire of modular exemplar-based memory models expressing kinematic motion. A module in such a vocabulary encodes a flow field (or gradient field) in joint angle space that describes the "flow" of kinematic motion for a particular skill-level behavior, enabling prediction from a given kinematic configuration. Second, we propose a data-driven method for deriving behavior vocabularies from time-series data of human motion using spatio-temporal dimension reduction and clustering. Results from evaluating an implementation of our methodology are presented along with the application of derived behavior vocabularies as predictors towards on-line humanoid trajectory formation and off-line motion synthesis.
Calcium, ATP, and ROS: a mitochondrial love-hate triangle
Authors: Brookes Paul S. , Yoon Yisang , Robotham James L. , Anders M. W. , Sheu Shey-Shing
Published: September 2004

The mitochondrion is at the core of cellular energy metabolism, being the site of most ATP generation. Calcium is a key regulator of mitochondrial function and acts at several levels within the organelle to stimulate ATP synthesis. However, the dysregulation of mitochondrial Ca2+ homeostasis is now recognized to play a key role in several pathologies. For example, mitochondrial matrix Ca2+ overload can lead to enhanced generation of reactive oxygen species, triggering of the permeability transition pore, and cytochrome c release, leading to apoptosis. Despite progress regarding the independent roles of both Ca2+ and mitochondrial dysfunction in disease, the molecular mechanisms by which Ca2+ can elicit mitochondrial dysfunction remain elusive. This review highlights the delicate balance between the positive and negative effects of Ca2+ and the signaling events that perturb this balance. Overall, a “two-hit” hypothesis is developed, in which Ca2+ plus another pathological stimulus can bring about mitochondrial dysfunction.
MKP-1 expression and stabilization and cGK Iα prevent diabetes- associated abnormalities in VSMC migration
Authors: Jacob Asha , Smolenski Albert , Lohmann Suzanne M. , Begum Najma
Published: September 2004

Diabetes mellitus is a major risk factor in the development of atherosclerosis and cardiovascular disease conditions, involving intimal injury and enhanced vascular smooth muscle cell (VSMC) migration. We report a mechanistic basis for divergences between insulin’s inhibitory effects on migration of aortic VSMC from control Wistar Kyoto (WKY) rats versus Goto-Kakizaki (GK) diabetic rats. In normal WKY VSMC, insulin increased MAPK phosphatase-1 (MKP-1) expression as well as MKP-1 phosphorylation, which stabilizes it, and inhibited PDGF-mediated MAPK phosphorylation and cell migration. In contrast, basal migration was elevated in GK diabetic VSMCs, and all of insulin’s effects on MKP-1 expression and phosphorylation, MAPK phosphorylation, and PDGF-stimulated migration were markedly inhibited. The critical importance of MKP-1 in insulin inhibition of VSMC migration was evident from several observations. MKP-1 small interfering RNA inhibited MKP-1 expression and abolished insulin inhibition of PDGF-induced VSMC migration. Conversely, adenoviral expression of MKP-1 decreased MAPK phosphorylation and basal migration rate and restored insulin's ability to inhibit PDGF-directed migration in GK diabetic VSMCs. Also, the proteasomal inhibitors lactacystin and MG132 partially restored MKP-1 protein levels in GK diabetic VSMCs and inhibited their migration. Furthermore, GK diabetic aortic VSMCs had reduced cGMP-dependent protein kinase Iα (cGK Iα) levels as well as insulin-dependent, but not sodium nitroprusside-dependent, stimulation of cGMP. Adenoviral expression of cGK Iα enhanced MKP-1 inhibition of MAPK phosphorylation and VSMC migration. We conclude that enhanced VSMC migration in GK diabetic rats is due at least in part to a failure of insulin-stimulated cGMP/cGK Iα signaling, MKP-1 expression, and stabilization and thus MAPK inactivation.