bluuebunny/crossref_metadata_2025 huggingface dataset:
GAUGING INTERNAL FERMIONIC SYMMETRIES AND SPIN-3/2 FIELDS
Authors: LOVE S. T.
Published: June 2003

Field theoretic models possessing a global internal fermionic shift symmetry are considered. When such a symmetry is realized locally, spin-3/2 fields appear naturally as gauge fields. Implementation of the gauging procedure requires not only the usual replacement of ordinary derivatives by covariant derivatives containing the spin-3/2 fields, but also the inclusion of additional monomials. The Higgs mechanism and the high energy Nambu–Goldstone fermion equivalence theorem are explicitly demonstrated.
EXTENDED PLANCK SCALE
Authors: COOPERSTOCK F. I. , FARAONI V.
Published: June 2003

Traditional derivations of the Planck mass ignore the role of charge and spin in general relativity. From the Kerr–Newman null surface and horizon radii, quantized charge and spin dependence are introduced in an extended Planck scale of mass. Spectra emerge with selection rules dependent upon the choice of Kerr–Newman radius to link with the Compton wavelength. The appearance of the fine structure constant suggests the possibility of a variation in time of the extended Planck mass, which may be much larger than the variation in the traditional one. There is a suggestion of a connection with the α value governing high-energy radiation in Z-boson production and decay.
A NOTE ON DUALITIES IN EINSTEIN'S GRAVITY IN THE PRESENCE OF A NON-MINIMALLY COUPLED SCALAR FIELD
Authors: ABRAMO L. R. , BRENIG L. , GUNZIG E. , SAA ALBERTO
Published: June 2003

We show that the action of Einstein's gravity with a scalar field coupled in a generic way to spacetime curvature is invariant under a particular set of conformal transformations. These transformations relate dual theories for which the effective couplings of the theory are scaled uniformly. In the simplest case, this class of dualities reduces to the S-duality of low-energy effective action of string theory.
D-BRANES, CYCLIC SYMMETRY AND NONCOMMUTATIVE GEOMETRY
Authors: KAR SUPRIYA
Published: June 2003

In this paper, we study the open string modes, describing the world-volume of a D p-brane, for its cyclic symmetry in the presence of a magnetic field. We outline the analogy between cyclic and noncommutative symmetries and demonstrate the point-splitting prescription to explain some of the unusual ir phenomena observed in a noncommutative field theory.
OVRO CMB ANISOTROPY MEASUREMENT CONSTRAINTS ON FLAT-Λ AND OPEN CDM COSMOGONIES
Authors: MUKHERJEE PIA , SOURADEEP TARUN , RATRA BHARAT , SUGIYAMA NAOSHI , GORSKI KRZYSZTOF M.
Published: June 2003

We use Owens Valley Radio Observatory (OVRO) cosmic microwave background (CMB) anisotropy data to constrain cosmological parameters. We account for the OVRO beamwidth and calibration uncertainties, as well as the uncertainty induced by the removal of non-CMB foreground contamination. We consider open and spatially-flat-Λ cold dark matter cosmogonies, with nonrelativistic-mass density parameter Ω0in the range 0.1–1, baryonic-mass density parameter ΩBin the range (0.005–0.029)h-2, and age of the universe t0in the range (10–20) Gyr. Marginalizing over all parameters but Ω0, the OVRO data favors an open (spatially-flat-Λ) model with Ω0≃ 0.33 (0.1). At the 2σ confidence level model normalizations deduced from the OVRO data are mostly consistent with those deduced from the DMR, UCSB South Pole 1994, Python I-III, ARGO, MAX 4 and 5, White Dish, and SuZIE data sets.
THE CANONICAL PATH INTEGRAL QUANTIZATION OF CHIRAL SCHWINGER MODEL
Authors: MUSLIH S. I.
Published: June 2003

We quantize the chiral Schwinger model by using the Hamilton–Jacobi formalism. We show that one can obtain the integrable set of equation of motion and the action function by using the integrability conditions of total differential equations and without any need to introduce unphysical auxiliary fields. The path integral for this model is obtained by using the canonical path integral method.
A COMPLETE YIELD CURVE DESCRIPTION OF A MARKOV INTEREST RATE MODEL
Authors: ELLIOTT ROBERT J. , MAMON ROGEMAR S.
Published: June 2003

This paper aims to present a complete term structure characterisation of a Markov interest rate model. To attain this objective, we first give a proof that establishes the Unbiased Expectation Hypothesis (UEH) via the forward measure. The UEH result is then employed, which considerably facilitates the calculation of an explicit analytic expression for the forward rate f(t, T). The specification of the bond price P(t, T), yield rate Y(t, T) and f(t, T) gives a complete set of yield curve descriptions for an interest rate market where the short rate r is a function of a continuous time Markov chain.
MODEL PERFORMANCE MEASURES FOR EXPECTED UTILITY MAXIMIZING INVESTORS
Authors: FRIEDMAN CRAIG , SANDOW SVEN
Published: June 2003

We examine model performance measures in four contexts: Discrete Probability, Continuous Probability, Conditional Discrete Probability and Conditional Probability Density Models. We consider the model performance question from the point of view of an investor who evaluates models based on the performance of the (optimal) strategies that the models suggest. Under this new paradigm, the investor selects the model with the highest estimated expected utility. We interpret our performance measures in information theoretic terms and provide new generalizations of entropy and Kullback-Leibler relative entropy. We show that the relative performance measure is independent of the market prices if and only if the investor's utility function is a member of a logarithmic family that admits a wide range of possible risk aversions. In this case, we show that the relative performance measure is equivalent to the (easily understood) differential expected growth of wealth or the (familiar) likelihood ratio. We state conditions under which relative performance measures for general utilities are well approximated by logarithmic-family-based relative performance measures. Some popular probability model performance measures (including ROC methods) are not consistent with our framework. We demonstrate that rank based performance measures can suggest model selections that are disastrous under various popular utilities.
WHICH PROCESS GIVES RISE TO THE OBSERVED DEPENDENCE OF SWAPTION IMPLIED VOLATILITY ON THE UNDERLYING?
Authors: REBONATO RICCARDO
Published: June 2003

In this paper we investigate whether a CEV model can account for the observed variation in the at-the-money implied volatility as a function of the level of the at-the-money forward rate. We also determine which exponent β in the CEV process for the swap rate best accounts for the observed behaviour of the implied volatilities.
Quantitative analysis of Li contents in LixCoO2cathodes via Rietveld refinement
Authors: Rodriguez Mark A. , Ingersoll David , Doughty Daniel H.
Published: June 2003

Rietveld refinement of LixCoO2-type cathodes (wherex=0.59–1.00) has been demonstrated to yield quantitative information about the Li occupancy with an error of about ∼10%. With careful X-ray diffraction (XRD) data collection, refinement, and proper calibration, accurate values can be obtained. Rietveld refinement tends to under-predict the Li occupancy values in charged (de-lithiated) cathodes as compared to ICP measurements. A Li-gradient model that assumes a decreasing concentration of Li from the particle core to its surface is discussed to explain this observation. The observed lattice parameters for the fully lithiated LiCoO2standard phase (R-3m symmetry) werea=2.8155(1) Å,c=14.052(1) Å. The error convention used in this paper is 3σ of standard deviations obtained from Rietveld refinement output.
Powder X-ray diffraction data of a new polymorph of HfMo2O8
Authors: Achary S. N. , Mukherjee G. D. , Tyagi A. K. , Godwal B. K.
Published: June 2003

A new polymorph of HfMo2O8 (β-form) is synthesized under high pressure and high temperature conditions. The powder X-ray diffraction (XRD) data could be explained based on a monoclinic lattice (Space Group: C2/c No. 15) with the unit cell parameters as: a=11.415(3), b=7.906(2), c=7.438(2) Å and β=122.37(2)°, V=566.9(2) Å3. The detailed powder XRD data and analysis are reported herein.
Improved crystallographic data for graphite
Authors: Howe J. Y. , Rawn C. J. , Jones L. E. , Ow H.
Published: June 2003

Powder diffraction pattern of SP-1 graphite has been obtained using synchrotron X-ray diffraction. Unit cell dimensions were calculated using a least-squares analysis that refined to a |Δ2θ°| of no more than 0.007. A hexagonal cell was determined with a space group of P63/mmc (194), a=2.4617(2) and c=6.7106 (4) Å. The Smith/Synder figure of merit is 167 based upon 11 peaks, which indicates that the quality of this data set is superior to the existing PDF card for graphite, 41-1487. It is also emphasized that the interlayer spacing of graphite should be 3.355(1) Å. Using GAS and EXPGUI codes, a new set of calculated powder diffraction data based upon the interlayer spacing of 3.555 Å is generated. A comparison with the current calculated card, 75-1621, has also been made.
Phosphorus: Newin situpowder data from large-volume apparatus
Authors: Crichton Wilson A. , Mezouar Mohamed , Monaco Giulio , Falconi Sara
Published: June 2003

Improved X-ray powder diffraction data for orthorhombic phosphorus, S.G.Cmca (64) obtainedin situat synthesis conditions of 1.2 GPa and 1100 K, are described. Representative, as synthesized, data include 2.552X, 3.3204, 2.5953, 5.1912, 1.6302, for least-squares unit-cella=3.3182(6) Å,b=10.3744(18) Å andc=4.3227(9) Å. As an illustration of the quality of the data, the structure was solved from powder XRD and Rietveld refined to givea=3.3199(2) Å,b= 10.3678(4) Å,c=4.3154(2)Å, andV=148.535(12) Å3with the P atom on 8f(1/2,y,z) withy=0.1044(22) andz=0.9179(7).
X-ray powder diffraction data of the novel copper and iron complexes as models for the active site in metalloproteins
Authors: Vlasenko V. G. , Shuvaev A. T. , Shuvaeva V. A. , Uraev A. I.
Published: June 2003

Two novel copper and iron chelates have been studied by powder diffraction. The cell parameters for triclinic (space group P 1 (2)) C25H21CuN3SO4 are a=9.636(2) Å; b=11.014(1) Å; c=11.233(3) Å; α=83.55(2); β=82.45(6); γ=76.36(2); Z=2; Dx=1.456 g cm−3. The monoclinic cell parameters (space group P 21/c (14)) for C40H30Cl4Fe2N8S2 are a=11.464(8) Å; b=17.462(1) Å; c=20.550(6) Å; β=103.534(1); Z=2; Dx=1.356 g cm−3.
Distorted chiolite crystal structures of α-Na5M3F14 (M=Cr,Fe,Ga) studied by X-ray powder diffraction
Authors: Le Bail A. , Mercier A.-M.
Published: June 2003

The crystal structures of the chiolite-related room temperature phases α-Na5M3F14 (MIII=Cr,Fe,Ga) are determined. For all of them, the space group is P21/n, Z=2; a=10.5096(3) Å, b=7.2253(2) Å, c=7.2713(2) Å, β=90.6753(7)° (M=Cr); a=10.4342(7) Å, b=7.3418(6) Å, c=7.4023(6) Å, β=90.799(5)° (M=Fe), and a=10.4052(1) Å, b=7.2251(1) Å, c=7.2689(1), β=90.6640(4)° (M=Ga). Rietveld refinements produce final RF factors 0.036, 0.033, and 0.035, and RWP factors, 0.125, 0.116, and 0.096, for MIII=Cr, Fe, and Ga, respectively. The MF6 polyhedra in the defective isolated perovskite-like layers deviate very few from perfect octahedra. Subtle octahedra tiltings lead to the symmetry decrease from the P4/mnc space group adopted by the Na5Al3F14 chiolite aristotype to the P21/n space group adopted by the title series. Facile twinning precluded till now the precise characterization of these compounds.
Powder X-ray diffraction study of LaCo0.5Ni0.5O3−δ and LaCo0.5Fe0.5O3−δ
Authors: Vyshatko N. P. , Kharton V. V. , Shaula A. L. , Marques F. M. B.
Published: June 2003

The crystal structures of LaCo0.5Ni0.5O3−δ and LaCo0.5Fe0.5O3−δ solid solutions, studied by powder X-ray diffraction, were found to be rhombohedral perovskite. The unit cell parameters in the hexagonal setting are a=5.491(6) Å and c=13.231(3) Å for LaCo0.5Fe0.5O3−δ, and a=5.464(4) Å and c=13.125(3) Å for LaCo0.5Ni0.5O3−δ. The space group is R3c (No. 167).
Results and conclusions of the internet based “Search/match round robin 2002”
Authors: Le Meins J-M. , Cranswick L. M. D. , Le Bail A.
Published: June 2003

To test the effectiveness of phase identification software, a two-stage search/match round robin using powder X-ray diffraction data was organized, through the internet and world wide web. The first stage provided powder patterns and a vague sample origin, the second stage provided the chemistry and sample history. While the statistics are not robust, it shows that routine phase identification without chemistry can be performed, providing effective modern third generation search/match software is used; the most up to date databases are available; and well trained, experienced scientists perform the analysis.
Rietveld refinement for indium nitride in the 105–295 K range
Authors: Paszkowicz W. , Černý R. , Krukowski S.
Published: June 2003

Results of Rietveld refinement for indium nitride data collected in the temperature range 105–295 K are presented. Acicular microcrystals of indium nitride prepared by reaction of liquid indium with nitrogen plasma were studied by X-ray diffraction. The diffraction measurements were carried out at the Swiss-Norwegian Beamline SNBL (ESRF) using a MAR345 image-plate detector. Excellent counting statistics allowed for refinement of the lattice parameters of InN as well as those of the metallic indium secondary phase. In the studied temperature range, the InN lattice parameters show a smooth increase that can be approximated by a linear function. Lattice-parameter dependencies confirm the trends indicated earlier by data measured using a conventional equipment. The relative change of both the a and c lattice parameters with increasing the temperature in the studied range is about 0.05%. The axial ratio slightly decreases with rising temperature. The experimental value of the free structural parameter, u=0.3769(14), is reported for InN for the first time. Its temperature variation is found to be considerably smaller than the experimental error. The thermal-expansion coefficients (TECs), derived from the linearly approximated lattice-parameter dependencies, are αa=3.09(14)×10−6 K−1 and αc=2.79(16)×10−6 K−1. The evaluated TECs are generally consistent with the earlier data. For the present dataset, the accuracy is apparently higher for both, the lattice parameters and thermal-expansion coefficients, than for the earlier results. The refined lattice parameter cIn of the indium secondary phase exhibits the known strongly nonlinear behavior; a shift (ΔT equal about −50 K) of the maximum in cIn(T) dependence is observed with respect to the literature data.
Rietveld refinements of a new solid solution Ba(3−x)Srx(PO4)2 (0≤x≤3)
Authors: Manoun B. , Popović L. , De Waal D. , Verryn S. M. C.
Published: June 2003

Ba(3−x)Srx(PO4)2 orthophosphates (0≤x≤3) have been prepared by solid state reaction. The final temperature was 1000°C. The X-ray diffraction analyses show the existence of a continuous solid solution. Ba(3−x)Srx(PO4)2 orthophosphates (0≤x≤3) crystallize in the hexagonal system with the space group R3m. Their structure is based on a three-dimensional framework constructed of infinite layers of Ba1/Sr1O12 linked and parallel to infinite layers of Ba2/Sr2O10 polyhedra and PO4 tetrahedra.
X-ray film as a two-dimensional detector for X-ray diffraction analysis
Authors: Blanton T. N.
Published: June 2003

Silver halide based photographic imaging elements have been utilized as detectors for X-rays for over 100 years. These elements comprised of gelatin dispersed silver halide coated on one or both sides of a support, have been utilized in diffraction experiments since the discovery of X-ray diffraction by Laue and co-workers. X-ray film has high spatial resolution and can be adapted to flat or curved two-dimensional detection geometries. This paper describes the use of X-ray film as a two-dimensional detector for X-ray diffraction analysis, and discusses X-ray film composition, exposure, and processing, along with considerations for analyzing X-ray diffraction data collected using X-ray film.
A new method for texture measurements using a general area detector diffraction system
Authors: Helming Kurt , Lyubchenko Mike , He Bob , Preckwinkel Uwe
Published: June 2003

Advances in X-ray texture solutions require new methods and descriptions for the texture analysis process, e.g., when using general area detector diffraction systems. A new method is presented that defines a general pole figure resolution and provides the possibility to optimize strategies for efficient pole figure data collection. Application of the new method improves resolution and (!) speed. New software enables simultaneous monitoring of pole and detector space. This allows a fundamentally better understanding of the collected information, e.g., in situations where peaks overlap or high backgrounds compromise data quality.
Microdiffraction applications utilizing a two-dimensional proportional detector
Authors: Tissot Ralph G.
Published: June 2003

Two-dimensional proportional detectors with their faster data collection, large dynamic range, and more available information than point or linear proportional detectors make them ideal for microdiffraction analysis. The unique capabilities of these detectors coupled with a rotating anode source, capillary optics, and a variety of accessories allow for a wide range of applications.
Novel, photon counting X-ray detectors
Authors: Durst R. D. , Diawara Y. , Khazins D. , Medved S. , Becker B. , Thorson T.
Published: June 2003

A novel sealed gaseous parallel plate avalanche chamber detector is described which is significantly less prone to discharges and can consequently achieve high gas gains at high counting rates. The detector has demonstrated stable gains greater than 104 at counting rates in excess of 107 counts/mm2 s.
c-fos Expression in the Forebrain after Mating in the Female Rat Is Altered by Adrenalectomy
Authors: Cameron Nicole , Erskine Mary S.
Published: June 2003

In rats of both sexes, mating stimulates neuronal activity in forebrain areas that are also activated by stress. Hypothalamic cells in the arcuate (ARC) and paraventricular (PVN) nuclei synthesize hormones or peptides whose levels are altered by adrenalectomy. In this experiment, we examined whether the mating-induced expression of c-fos in the forebrain is altered by adrenalectomy (Adx) in female rats. Ovariectomized females were adrenalectomized (Adx) or sham-operated (Sham), hormone-primed and mated 2 weeks after surgery. They received 15 intromissions (15I), 5 intromissions (5I) or 15 mounts without intromission (MO) from a male or were taken directly from their home cage (HC). Two hours after mating, rats were perfused with paraformaldehyde and their brains were collected and stained immunocytochemically for FOS protein. FOS-immunoreactive (FOS-IR) cells in the posterodorsal medial amygdala (MePD), bed nucleus of stria terminalis (BNST), ventromedial hypothalamus (VMH), medial preoptic area (mPOA), ARC and PVN were counted bilaterally. In Sham animals, intromissions produced significant increases in FOS above HC levels. In Adx animals, mating increased FOS activity in all areas. However, responses to 5I and 15I differed between Sham and Adx groups. In all areas, Shams showed either the highest FOS response following 15I or levels which were equivalent after 5I and 15I. In Adx animals, the greatest number of FOS-positive cells occurred after 5I, with the 15I group showing significant suppression of FOS below 5I levels in the VMH, mPOA, ARC and PVN. These results demonstrate that the adrenal modulates FOS responses to mating in the female rat and suggest that adrenal secretory products normally may decrease sensitivity to low levels of mating stimulation. These effects may be due to increased corticotropin-releasing hormone (CRH) or β-endorphin in the hypothalamus after adrenalectomy.
The Roots of Coherence in Discourse
Authors: Levy Elena T.
Published: June 2003

This article is concerned with the emergence of logical coherence across children’s repetitions of their own narrative discourse. I propose that coherence does not emerge in isolation of language, but that it depends on the use and manipulation, in ongoing speech, of specific linguistic forms, such as the clause-linking devices that form part of the cohesive system, the text-forming component of language. Using observations from a young child’s spontaneous speech and from older children’s elicited narrations, I propose that a function of repeated language play is to set up subsequent discourse for the use of increasingly compact sequences of clauses. This creates narrative compression, an integration of clauses that is not only structural but semantic as well, and that corresponds to a description of events that is more coherent than what was originally described. I point out parallels to the grammaticalization of discourse across both diachronic and longer-term ontogenetic time, and I place the findings within a developmental and social framework.
Infants in Groups: A Paradigm for the Study of Early Social Experience
Authors: Selby Jane M. , Bradley Benjamin Sylvester
Published: June 2003

This paper reports on a two-stage, case-based analysis of infant sociability in infant-only trios to illustrate how findings made using this approach extend our theoretical understanding of early intersubjectivity. Studying infant groups allows us to address three kinds of emerging theoretical argument: (1) that babies are born with a ‘general relational capacity’ which complements or even founds the more specific ‘dyadic program’ that generates attachments; (2) that infants’ communication with peers is the best route to understanding the shared meanings that inform language acquisition, and (3) that the reconceptualisation of ‘nonbasic’ emotions requires we discover whether babies are communicatively competent to elaborate context-specific meanings over time. The materials we use to illustrate this two-stage approach show infants manifest core characteristics of group-communication in the second six months of life, in particular the capacity to be involved with more than one person at a time and for relational encounters to shift behavioral significances for the infants as a product of group interactions.
Variations in Nutritional Status of Elderly Men and Women according to Place of Residence
Authors: Sibai Abla-Mehio , Zard Chantal , Adra Nada , Baydoun May , Hwalla (Baba) Nahla
Published: June 2003

Objective: The purpose of this study was to assess comprehensively the nutritional status of elderly individuals in institutions and to compare it with that of community based dwellers in an urban setting in Lebanon. Methods: Participants included 100 elderly men and women (aged 65 years and older) selected randomly from four institutions who were based on sex and neighborhood with 100 free-living individuals. Subjects were mentally and physically capable of responding to an interview schedule. Their nutritional status was assessed by anthropometric measurements, dietary food intake for a 3-day period, and hematological and biochemical variables. Energy and macro- and micronutrient intakes were compared with the US recommended dietary allowances (RDA) or dietary reference intakes (DRI) as appropriate. Results: Elderly living at home had significantly higher mean body mass index and waist circumference than those living in institutions. Although the total energy intake was comparable between the two groups, the elderly in the institutions consumed more fat and had lower intake of dietary fibers. Deficiencies (below 2/3rd RDA/DRI intakes) in zinc, magnesium, α-tocopherol, vitamins A and D, and pyridoxine were noted in both study groups with overall higher proportions observed among the institutionalized elderly. These were also anemic (42.5%) and had low levels of albumin (27.5%). In contrast, those living at home showed a higher prevalence of obesity and a lower calcium intake. Multivariate analysis controlling for a number of potential covariates did not change the results observed. Conclusions: The results of the present study showed a higher prevalence of obesity in those living at home and varying deficiencies by place of residence with no evidence that duration of institutionalization in itself being associated with poor nutritional status. Awareness of the risks associated with these deficiencies and excesses should address the lay and health professionals working in the community and institutions alike.
Temporal Surveillance of the Humoral Immunity against Influenza Vaccine in the Elderly over 9 Consecutive Years
Authors: Odelin Marie-France , Momplot Corinne , Bourlet Thomas , Gonthier Régis , Aymard Michèle , Pozzetto Bruno
Published: June 2003

Background: The effect of age on declining immunity is well established, but its influence on humoral responses to influenza vaccines is still debated. Objective: To compare prospectively the immunogenicity of an influenza vaccine in elderly and healthy control subjects and to search for correlations between this specific humoral protection and clinical and virological parameters. Methods: A prospective study of the humoral response to influenza vaccine was conducted over 9 consecutive years in the long-term care units of the Saint-Etienne University Hospital, France. Antibodies directed against the vaccinal strains in an inactivated trivalent vaccine were tested by radial haemolysis before and 1 month after 477 and 242 cumulative annual vaccinations in elderly people and in healthy controls, respectively. During the last 6 years of the study, clinical samples from patients with fever ≧38°C were tested systematically for the diagnosis of an influenza infection. Results: A significant rise in anti-A/H3N2 antibody titres was observed in 49.3% of the elderly subjects and in 48.3% of the controls (not significant). The rises for the A/H1N1 and B strains were 31.4 and 39.2% (p < 0.001) and 30.6 and 40.5 (p < 0.001), respectively. When control subjects under 31 years old were excluded, no significant difference was recorded for any strain. Only 3.9% of the vaccinated elderly experienced any clinical influenza infection as defined by fever ≧38°C and virological proof. Conclusions: The humoral response to influenza immunization is not impaired in the elderly compared with middle-aged controls, and the incidence of febrile episodes due to influenza is low in this vaccinated elderly population. These findings provide further evidence supporting the recommendation for annual influenza vaccination in the elderly.
Effects of Regular Walking on Postural Stability in the Elderly
Authors: Melzer I. , Benjuya N. , Kaplanski J.
Published: June 2003

Background: Both age and lack of physical activity may be responsible for poor health and poor balance control. Conversely, physical activity may modulate postural control in elderly people. Objective: An observational study was performed in older adults to explore whether walking on a regular basis might prove to be beneficial not only to the cardiovascular system but also to maintaining a good balance. Methods: Twenty-two healthy older subjects walking on a regular basis (DW group) and 121 healthy control older subjects who did not walk regularly (NW group) were studied. The subjects included in the study were free from major gait and postural disorders. An instrumented force platform was used to measure the time-varying displacements of the center of pressure under eight static conditions and postural limit tests. An isometric test was performed to evaluate lower limb muscle strength, and a static two-point discrimination test evaluated the innervation density of the slowly adapting receptors of the sole of the first toe. Results: The DW group had a significantly better (p < 0.05) postural stability under static conditions than the NW group. There were no significant differences in postural limit tests and in two-point discrimination between the groups. The DW group had significantly higher values of ankle plantar flexor and knee extensor strengths, while there were no significant differences in ankle dorsiflexors and knee flexors. None of the DW group reported experiencing a fall during the previous 6 months compared with 16% in the NW group who reported at least two falls during the last half year. Conclusions: Walking on a regular basis in old age may have the potential to modulate stability. It was found that healthy older subjects, who walked on a regular basis since their retirement, have better postural control, especially in their static balance, than those who do not. The laboratory results were accompanied by the important finding that although older subjects who walk on a regular basis walked much more than nonwalkers, they did not suffer from falls.
Age-Correlated Changes of the Erythrocyte Catalase Activity in the Spanish Population
Authors: Casado Angela , López-Fernández María Encarnación
Published: June 2003

Background: Oxygen free radical and reactive oxygen species are involved in many diseases and ageing. Scavening enzymes represent one of the several natural defence mechanisms against free radical induced damage. Catalase (CAT) is an enzyme that is involved in antioxidant defence. Objective: In order to establish a comprehensive profile of the erythrocyte CAT activity during ageing, we investigated this activity in human erythrocytes from 2,827 apparently healthy Spanish subjects (1,388 males and 1,439 females). Methods: We divided the subjects into twelve age groups (newborns and 1–3, 4–9, 10–19, 20–29, 30–39, 40–49, 50–59, 60–69, 70–79, 80–89, and >90 years of age) to evaluate ageing changes. The CAT activity was measured in haemolysates by the method of Aebi (see text). Results: No significant variations with respect to sex were detected, except for the 70- to 93-year age groups. In these elderly subjects, the CAT activity in males remained constant with no significant variations between age groups, whereas the CAT activity showed a significant increase in females. This fact is considered to be one of the outcomes of the greater longevity in females. Significant age-related modifications in erythrocyte CAT activity appeared in the group of newborns (p < 0.001), in the group 1–3 years of age (p < 0.025), and in the elderly groups: 70–79 years (p < 0.025) and 80–89 years (p < 0.05) of age. Conclusion: Our results confirm that the CAT activity in the Spanish population shows an interindividual variability and suggest that this variability may be due, at least in part, to the age of the individuals.
Low Serum Albumin Levels, Confusion, and Fecal Incontinence: Are These Risk Factors for Pressure Ulcers in Mobility-Impaired Hospitalized Adults?
Authors: Reed Richard L. , Hepburn Kenneth , Adelson Richard , Center Bruce , McKnight Patrick
Published: June 2003

Background: Studies of risk factors for clinically significant pressure ulcers in the hospital have been limited by the small number of study subjects that develop pressure ulcers, resulting in contradictory findings regarding some risk factors. Objective: To determine if three risk factors (low serum albumin level, fecal incontinence, and confusion) were significant risk factors when tested in a large data set. Methods: The study design was a longitudinal cohort study using data collected as a component of a multi-site controlled clinical trial. The data were collected at 47 Veterans Affairs Hospitals. 2,771 subjects that required high levels of nursing care were identified to have mobility impairment. Their medical records were abstracted using a standard form to identify a large number of potential risk factors. The subsequent development of stage 2 or greater pressure ulcers was recorded for a maximum of 14 days after admission. Results: 406 patients (14.7%) subsequently developed at least one stage 2 or greater pressure ulcer over a 2-week period. In a multivariate model, the presence of low albumin levels (odds ratio OR = 1.40) and confusion (OR = 1.45) were both found to be statistically significant risk factors, while fecal incontinence was not. Having a Do Not Resuscitate (DNR) order was also a significant risk factor (OR = 1.55). Two other known risk factors also entered the model: being malnourished (OR = 1.69) and requiring a urinary catheter (OR = 1.55). Conclusions: This study confirmed confusion and low albumin as pressure ulcer risk factors, but not fecal incontinence. A DNR order was found to be a new pressure ulcer risk factor not previously described in the literature.
Postprandial Systolic Blood Pressure Responses of Older People in Residential Care: Association with Risk of Falling
Authors: Le Couteur David G. , Fisher Alex A. , Davis Michael W. , McLean Allan J.
Published: June 2003

Background: The association between postprandial blood pressure, falls and medications is controversial. Objective: To investigate cardiovascular responses to meals in elderly people together with clinical associations and therapeutic issues. Methods: A cross-sectional observational study of 179 semi-independent older people (age 83.2 ± 7.0 years) in residential care facilities was undertaken. Data on the frequency of falls, medical and medication history and measurement of blood pressure before and after a breakfast meal, and then after standing and walking after the meal were documented. Results: Postprandial hypotension (≧20 mm Hg fall in systolic blood pressure (SBP)) and low absolute SBP (≤115 mm Hg) were common after meals and exacerbated by standing. Risk factors for low postprandial SBP included use of selective serotonin reuptake inhibitors (OR = 4.3, CI 1.4–13.1, p = 0.006), antipsychotic medications (OR = 5.2, CI 1.4–19.2, p = 0.007) and a history of smoking (OR = 4.7, CI 1.5–14.9, p = 0.005). Antihypertensive therapy ameliorated the postprandial decline in blood pressure. The incidence of falls was increased only in the 10% of subjects with low postprandial SBP. Conclusions: Significant adverse cardiovascular change is common after meals in older people and a postprandial SBP of <115 mm Hg was associated with a history of falls. Selective serotonin reuptake inhibitors and antipsychotic medications were associated with low postprandial SBP, which may provide a mechanism for their association with falls. Hypertension was positively and antihypertensive therapy negatively associated with postprandial hypotension.
Self-Rated Life Expectancy as a Predictor of Mortality: Evidence from the HRS and AHEAD Surveys
Authors: Siegel Michele , Bradley Elizabeth H. , Kasl Stanislav V.
Published: June 2003

Background: An extensive literature has demonstrated that self-ratings of health predict mortality, even after controlling for more objective measures of health, health habits and sociodemographic characteristics. We examine the role of a related concept, self-rated life expectancy, in predicting mortality. Objective: To assess whether self-rated life expectancy predicts mortality after controlling for measures of health, self-rated health, and sociodemographic characteristics. Methods: Using data from the 1992 Health and Retirement Survey (HRS), the 1993 Asset and Health Dynamics Among the Oldest Old (AHEAD) survey, and the second Tracker file (2.0), Cox proportional hazard models were estimated to assess whether self-rated life expectancy predicts mortality, after adjusting for self-rated health and several potential confounders that might otherwise explain this relationship. The AHEAD sample included 2,102 men and 3,160 women. During the 2 years of follow-up, 9% (n = 185) of the men died and 5% (n = 166) of the women died. The HRS sample was comprised of 4,090 men and 4,885 women. Four percent (n = 164) of the men died and 2% (n = 99) of the women died in the 3 years of follow-up. Results: In the older, AHEAD sample, both self-rated life expectancy (p < 0.01) and self-rated health (p < 0.05) predicted mortality for both men and women, even when the two measures were included in the model together. In the younger, HRS sample, self-rated life expectancy was not significantly associated with mortality when self-rated health was included in the model. Conclusion: Our findings suggest that, although self-rated life expectancy and self-rated health may be conceptually related, they have independent empirical effects on mortality.
Incidence of Amyotrophic Lateral Sclerosis in the Local Health District of Ferrara, Italy, 1964–1998
Authors: Govoni Vittorio , Granieri Enrico , Capone Jay , Manconi Mauro , Casetta Ilaria
Published: June 2003

One of the epidemiologic characteristics of amyotrophic lateral sclerosis (ALS) still under discussion is whether the incidence of ALS is increasing over time. We performed a new investigation expanding our previous study of ALS in the local health district (LHD) of Ferrara, northern Italy, to determine whether there have been any changes in the incidence of ALS in the years 1964–1998. We used a complete enumeration approach by reviewing all possible sources of case collection available in the study area. We selected all patients with definite and probable ALS according to the World Federation of Neurology criteria. The mean annual crude incidence rate for 1964–1998 was 1.63 per 100,000 population (95% CI 1.31–2.00). An increase in incidence from 1.07 to 2.19 per 100,000 population was observed during the study period. It was greater in women and in individuals of 70 years old and over. Substantial population ageing occurred in the LHD of Ferrara during the study period and it was more prominent in women. This increase in incidence seems to be explained mainly by the ageing of the population. Moreover, greater precision in diagnosis of ALS in elderly women, rather than better case ascertainment of diagnosed patients, may have contributed to the increase. The role of environmental factors cannot be excluded, but based on the present findings, it seems to be of little importance.
A4T Mutation in the SOD1 Gene Causing Familial Amyotrophic Lateral Sclerosis
Authors: Aksoy Hatice , Dean Geoffrey , Elian Marta , Deng H.X. , Deng Gang , Juneja Tony , Storey Elsdon , McKinlay Gardner R.J. , Jacob Rebecca L. , Laing Nigel G. , Siddique Teepu
Published: June 2003

We report the clinical and laboratory findings in the largest kindred so far recorded with familial amyotrophic lateral sclerosis due to an A4T mutation in the SOD1 gene. The age of onset ranged from 32 to 60 years, with a mean of 46 years. Weakness in the legs was the most frequent early symptom and there was a predominance of lower motor neuron signs. The mean time from onset of symptoms to death was 14 months. One man with onset at the age of 37 has shown a slowly developing form and is currently alive 76 months after diagnosis (October 2002), although severely affected. The A4T mutation, with one exception, was of similar severity to the A4V mutation.
Spouses and Unrelated Friends of Probands as Controls for Stroke Genetics Studies
Authors: Worrall Bradford Burke , Brown Devin L. , Brott Thomas G. , Brown Robert D. , Silliman Scott L. , Meschia James F.
Published: June 2003

To plan a multisite, ischemic stroke genetic study, stroke patients were surveyed about the availability and characteristics of a convenience sample of spouse/friend controls. 65% of all stroke-affected probands reported a living spouse. A more detailed survey was conducted at the University of Virginia, Charlottesville, Va., USA: 51% of stroke patients reported a living, stroke-free spouse who would be willing to serve as a control, and 49% reported having a stroke-free friend who would be willing to serve as a control. Overall, 75% of stroke patients reported at least 1 individual willing to participate as a control. Cases without an identified control were more likely to be non-white (48%) than were cases with a control (13%; p = 0.00004). Cases were older than controls (67.3 vs. 59.2 years; p = 0.000002), and a greater proportion of cases than controls were male (57 vs. 33%; p = 0.0002). Without proper attention to matching, the use of a spouse/friend convenience sample would result in imbalances in basic demographic characteristics.
Reproductive Factors Have Low Impact on the Risk of Different Primary Brain Tumours in Offspring
Authors: Mogren Ingrid , Malmer Beatrice , Tavelin Björn , Damber Lena
Published: June 2003

Objectives: The aim of our study was to investigate whether reproductive factors influence the risk of primary brain tumours (PBT) in offspring. Methods: Data on all deliveries in two Swedish counties from 1955 to 1990 were extracted from two birth registries. The follow-up period closed at the end of 1994, with subjects followed up to early middle age. Incidence rates of malignancy for 1958–1994 were obtained from the Swedish Cancer Registry. Standardised incidence ratios (SIR) and relative risks were calculated for astrocytomas, primitive neuroectodermal tumour, ependymoma and meningiomas in offspring. Results: Few associations were detected. High birth weight indicated an increased risk for astrocytomas grade I and II for all primary brain tumours, and the risk was close to significance for astrocytomas grade I–II (SIR = 3.64; CI = 0.98–9.31). For children under 15 years of age the risk for astrocytomas grade I and II was further increased (SIR = 4.44; CI = 1.19–11.38). Conclusions: A consistent pattern of non-association indicated a low impact of intrauterine environment on the future development of primary brain tumours in offspring up to early middle age.
‘Friction and Adhesive Forces’ – Possible Underlying Causes for Temporomandibular Joint Internal Derangement
Authors: Nitzan D.W.
Published: June 2003

Since normal temporomandibular joint (TMJ) movements depend primarily on the disc freely sliding down the slope of the eminence, understanding how aberrations in the lubrication system contribute to TMJ dysfunction is clearly critically important. It provides a possible explanation for the genesis of disc displacement and helps make us familiar with the clinical appearance and ways of treating limited mouth opening caused by the anchored disc phenomenon (ADP) versus disc displacement without reduction, TMJ open lock versus dislocation and osteoarthritis. This understanding clarifies the efficiency of procedures such as joint hydraulic pump, arthrocentesis and arthroscopic lavage and lysis particularly in ADP, open lock and osteoarthritis.
Pathophysiological Mechanisms in Osteoarthritis Lead to Novel Therapeutic Strategies
Authors: Malemud Charles J. , Islam Najmul , Haqqi Tariq M.
Published: June 2003

Osteoarthritis (OA) is a debilitating, progressive disease of diarthrodial joints associated with aging. At the molecular level, OA is characterized by an imbalance between anabolic (i.e. extracellular matrix biosynthesis) and catabolic (i.e. extracellular matrix degradation) pathways in which articular cartilage is the principal site of tissue injury responses. The pathophysiology of OA also involves the synovium in that ‘nonclassical’ inflammatory synovial processes contribute to OA progression. Chondrocytes are critical to the OA process in that the progression of OA can be judged by the vitality of chondrocytes and their ability to resist apoptosis. Growth factors exemplified by insulin-like growth factor-1, its binding proteins and transforming growth factor-β contribute to anabolic pathways including compensatory biosynthesis of extracellular matrix proteins. Catabolic pathways are altered by cytokine genes such as interleukin-1 (IL-1) and tumor necrosis factor-α (TNF-α) which are upregulated in OA. In addition, IL-1 and TNF-α downregulate extracellular matrix protein biosynthesis while concomitantly upregulating matrix metalloproteinase (MMP) gene expression. When MMPs are activated, cartilage extracellular matrix degradation ensues apparently because levels of endogenous cartilage MMP inhibitors cannot regulate MMP activity. Therapeutic strategies designed to modulate the imbalance between anabolic and catabolic pathways in OA may include neutralizing cytokine activity or MMP gene expression or inhibiting signaling pathways which result in apoptosis dependent on mature caspase activity or mitogen-activated protein kinase (MAPK) activity. MAPK activity appears critical for regulating chondrocyte and synoviocyte apoptosis and MMP genes.
Induction of Early Growth Response Gene Egr2 by Basic Calcium Phosphate Crystals through a Calcium-Dependent Protein Kinase C-Independent p44/42 Mitogen-Activated Protein Kinase Pathway
Authors: Zeng Xiao R. , Sun Yubo , Wenger Leonor , Cheung Herman S.
Published: June 2003

Using the reverse transcriptase-polymerase chain reaction we examined the effect of basic calcium phosphate (BCP) crystals on the induction of the early growth response gene Egr2 transcription and the signal transduction pathway involved. The results showed that BCP crystals induced Egr2 transcription up to 8-fold, peaking at 24 h after treatment. The induction of Egr2 was confirmed by transient transfection assays using an Egr2 promoter/luciferase reporter construct and could be inhibited by the p44/42 mitogen-activated protein kinase (MAPK)-specific inhibitor U0126, or by calcium chelator TMB-8, but not by the SAPK2/p38 MAPK inhibitor SB202190 or by the protein kinase C inhibitor bisindolylmaleimide I (Bis-I). Using the Mercury Pathway Profiling System (Clontech, Palo Alto, Calif., USA) we further showed that induced Egr2 could stimulate the activities of several transcription factors that are associated with cell proliferation, such as c-fos, SRF and c-myc.
Specialized Cranial Muscles: How Different Are They from Limb and Abdominal Muscles?
Authors: Sciote James J. , Horton Michael J. , Rowlerson Anthea M. , Link Jason
Published: June 2003

Mammalian skeletal muscle fibers can be classified into functional types by the heavy chain (MyHC) and light chain (MyLC) isoforms of myosin (the primary motor protein) that they contain. Most human skeletal muscle contains fiber types and myosin isoforms I, IIA and IIX. Some highly specialized muscle fibers in human extraocular and jaw-closing muscles express either novel myosins or unusual combinations of isoforms of unknown functional significance. Extrinsic laryngeal muscles may express the extraocular MyHC isoform for rapid contraction and a tonic MyHC isoform for slow tonic contractions. In jaw-closing muscles, fiber phenotypes and myosin expression have been characterized as highly unusual. The jaw-closing muscles of most carnivores and primates have tissue-specific expression of the type IIM or ‘type II masticatory’ MyHC. Human jaw-closing muscles, however, do not contain IIM myosin. Rather, they express myosins typical of developing or cardiac muscle in addition to type I, IIA and IIX myosins, and many of their fibers are hybrids, expressing two or more isoforms. Fiber morphology is also unusual in that the type II fibers are mostly of smaller diameter than type I. By combining physiological and biochemical techniques it is possible to determine the maximum velocity of unloaded shortening (Vo) of an individual skeletal muscle fiber and subsequently determine the type and amount of myosin isoform. When analyzed, some laryngeal fibers shorten at much faster rates than type II fibers from limb and abdominal muscle. Yet some type I fibers in masseter show an opposite trend towards speeds 10-fold slower than type I fibers of limb muscle. These unusual shortening velocities are most probably regulated by MyHC isoforms in laryngeal fibers and by MyLC isoforms in masseter. For the jaw-closing muscles, this finding represents the first case in human muscle of physiological regulation of kinetics by light chains. Together, these results demonstrate that, compared to other skeletal muscles, cranial muscles have a wider repertoire of contractile protein expression and function. Molecular techniques for reverse transcription of mRNA and amplification by polymerase chain reaction have been applied to typing of single fibers isolated from limb muscles, successfully identifying pure type I, IIA and IIX and hybrid type I/IIA and IIA/IIX fibers. This demonstrates the potential for future studies of the regulation of gene expression in jaw-closing and laryngeal muscles, which have such a variety of complex fiber types fitting them for their roles in vivo.