4,776 research outputs found

    Covariant q-differential operators and unitary highest weight representations for U_q su(n,n)

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    We investigate a one-parameter family of quantum Harish-Chandra modules of U_q sl(2n). This family is an analog of the holomorphic discrete series of representations of the group SU(n,n) for the quantum group U_q su(n, n). We introduce a q-analog of "the wave" operator (a determinant-type differential operator) and prove certain covariance property of its powers. This result is applied to the study of some quotients of the above-mentioned quantum Harish-Chandra modules. We also prove an analog of a known result by J.Faraut and A.Koranyi on the expansion of reproducing kernels which determines the analytic continuation of the holomorphic discrete series.Comment: 26 page

    Photonic crystal fiber with a hybrid honeycomb cladding

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    We consider an air-silica honeycomb lattice and demonstrate a new approach to the formation of a core defect. Typically, a high or low-index core is formed by adding a high-index region or an additional air-hole (or other low-index material) to the lattice, but here we discuss how a core defect can be formed by manipulating the cladding region rather than the core region itself. Germanium-doping of the honeycomb lattice has recently been suggested for the formation of a photonic band-gap guiding silica-core and here we experimentally demonstrate how an index-guiding silica-core can be formed by fluorine-doping of the honeycomb lattice.Comment: 5 pages including 3 figures. Accepted for Optics Expres

    Frequency Dependent Specific Heat from Thermal Effusion in Spherical Geometry

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    We present a novel method of measuring the frequency dependent specific heat at the glass transition applied to 5-polyphenyl-4-ether. The method employs thermal waves effusing radially out from the surface of a spherical thermistor that acts as both a heat generator and thermometer. It is a merit of the method compared to planar effusion methods that the influence of the mechanical boundary conditions are analytically known. This implies that it is the longitudinal rather than the isobaric specific heat that is measured. As another merit the thermal conductivity and specific heat can be found independently. The method has highest sensitivity at a frequency where the thermal diffusion length is comparable to the radius of the heat generator. This limits in practise the frequency range to 2-3 decades. An account of the 3omega-technique used including higher order terms in the temperature dependency of the thermistor and in the power generated is furthermore given.Comment: 17 pages, 15 figures, Substantially revised versio

    Harmonizing Software Standards with a Semantic Model

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    The application of standards in the software development process supports interoperability between systems. Maintenance of standards must be guaranteed on the organisational and technical level. The use of semantic technologies can contribute to the standard maintenance process by providing a harmonizing bridge between standards of different knowledge domains and languages and by providing a single point of administration for standard domain concepts. This paper describes a case study of the creation of a semantic layer between software standards for water management systems in The Netherland

    Intranasal immunization with pneumococcal polysaccharide conjugate vaccines protects mice against invasive pneumococcal infections.

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    To access publisher full text version of this article. Please click on the hyperlink in Additional Links fieldHost defenses against Streptococcus pneumoniae depend largely on opsonophagocytosis mediated by antibodies and complement. Since pneumococcus is a respiratory pathogen, mucosal immune responses may play a significant role in the defense against pneumococcal infections. Thus, mucosal vaccination may be an alternative approach to current immunization strategies, but effective adjuvants are required. Protein antigens induce significant mucosal immunoglobulin A (IgA) and systemic IgG responses when administered intranasally (i. n.) with the glyceride-polysorbate based adjuvant RhinoVax (RV) both in experimental animals and humans. The immunogenicity and efficacy of pneumococcal polysaccharide conjugate vaccines (PNC) of serotypes 1 and 3 was studied in mice after i.n. immunization with RV. Antibodies were measured in serum (IgM, IgG, and IgA) and saliva (IgA) and compared to antibody titers induced by parenteral immunization. The PNCs induced significant systemic IgG and IgA antibodies after i.n. immunization only when given with RV and, for serotype 1, serum IgG titers were comparable to titers induced by subcutaneous immunization. In addition, i.n. immunization with PNC-1 in RV elicited detectable mucosal IgA. These results demonstrate that RV is a potent mucosal adjuvant for polysaccharides conjugated to proteins. A majority of the PNC-1-immunized mice were protected against both bacteremia and pneumonia after i.n. challenge with a lethal dose of serotype 1 pneumococci, and protection correlated significantly with the serum IgG titers. Similarly, the survival of mice immunized i.n. with PNC-3 in RV was significantly prolonged. These results indicate that mucosal vaccination with PNC and adjuvants may be an alternative strategy for prevention against pneumococcal infections

    Intranasal immunization with pneumococcal polysaccharide conjugate vaccines with nontoxic mutants of Escherichia coli heat-labile enterotoxins as adjuvants protects mice against invasive pneumococcal infections

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    To access publisher full text version of this article. Please click on the hyperlink in Additional Links fieldHost defenses against Streptococcus pneumoniae depend largely on phagocytosis following opsonization by polysaccharide-specific immunoglobulin G (IgG) antibodies and complement. Since colonization of the respiratory mucosa is the first step in pneumococcal pathogenesis, mucosal immune responses may play a significant role. In addition to inducing systemic immune responses, mucosal vaccination with an effective adjuvant has the advantage of inducing mucosal IgA antibodies. The heat-labile enterotoxin (LT) of Escherichia coli is a well-studied mucosal adjuvant, and adjuvant activity of nontoxic LT mutants has been demonstrated for several protein antigens. We investigated the immunogenicity of pneumococcal polysaccharide conjugate vaccines (PNC) of serotypes 1 and 3 in mice after intranasal (i.n.) immunization by using as an adjuvant the nontoxic LT mutant LT-K63 or LT-R72, which has minimal residual toxicity. Pneumococcal serotype-specific antibodies were measured in serum (IgM, IgG, and IgA) and saliva (IgA), and vaccine-induced protection was evaluated by i.n. challenge with virulent pneumococci of the homologous serotype. When administered with LT mutants, i.n. immunization with both conjugates induced systemic and mucosal immune responses, and serum IgG antibody levels were significantly higher than after subcutaneous immunization. All mice immunized i.n. with PNC-1 and LT mutants were protected against bacteremia and cleared the pneumococci from the lung 24 h after i.n. challenge; pneumococcal density correlated significantly with serum IgG antibody levels. Similarly, the survival of mice immunized i.n. with PNC-3 and LT mutants was significantly prolonged. These results demonstrate that i.n. vaccination with PNC and potent adjuvants can protect mice against invasive and lethal pneumococcal infections, indicating that mucosal vaccination with PNC may be an alternative vaccination strategy for humans

    Intergalactic HeII absorption towards QSO 1157+3143

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    We report the discovery of a further line of sight allowing detection of HeII Ly alpha absorption by the intergalactic medium. A HST/STIS survey of 32 bright z ~ 3 quasars selected from the Hamburg Quasar Surveys yielded one detection toward QSO 1157+3143 (z ~ 3, B ~ 17). A 10 orbit follow-up spectrum reveals a UV spectrum significantly supressed by two intervening Lyman limit systems at z=2.77 and 2.94, but with the continuum flux recovering sufficiently shortward of ~ 1700 A to allow study of the HeII absorption spectrum in the redshift range 2.75 < z < 2.97. The absorption is characterized by alternating voids and dense filament structures seen in both HeII and HI. Attempts to model the HeII opacity in terms of HI Ly alpha forest absorption are not successful in the voids, suggesting that HeII reionization is not complete between z=2.77 and 2.97 or that an optically thin Lyman limit system with z ~ 0.3 is responsible for the additional opacity.Comment: 6 pages, 4 figures, accepted by A&

    Dietary determinants of changes in waist circumference adjusted for body mass index - a proxy measure of visceral adiposity

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    Background Given the recognized health effects of visceral fat, the understanding of how diet can modulate changes in the phenotype “waist circumference for a given body mass index (WCBMI)”, a proxy measure of visceral adiposity, is deemed necessary. Hence, the objective of the present study was to assess the association between dietary factors and prospective changes in visceral adiposity as measured by changes in the phenotype WCBMI. Methods and Findings We analyzed data from 48,631 men and women from 5 countries participating in the European Prospective Investigation into Cancer and Nutrition (EPIC) study. Anthropometric measurements were obtained at baseline and after a median follow-up time of 5.5 years. WCBMI was defined as the residuals of waist circumference regressed on body mass index, and annual change in WCBMI (¿WCBMI, cm/y) was defined as the difference between residuals at follow-up and baseline, divided by follow-up time. The association between energy, energy density (ED), macronutrients, alcohol, glycemic index (GI), glycemic load (GL), fibre and ¿WCBMI was modelled using centre-specific adjusted linear regression, and random-effects meta-analyses to obtain pooled estimates. Men and women with higher ED and GI diets showed significant increases in their WCBMI, compared to those with lower ED and GI [1 kcal/g greater ED predicted a ¿WCBMI of 0.09 cm (95% CI 0.05 to 0.13) in men and 0.15 cm (95% CI 0.09 to 0.21) in women; 10 units greater GI predicted a ¿WCBMI of 0.07 cm (95% CI 0.03 to 0.12) in men and 0.06 cm (95% CI 0.03 to 0.10) in women]. Among women, lower fibre intake, higher GL, and higher alcohol consumption also predicted a higher ¿WCBMI. Conclusions Results of this study suggest that a diet with low GI and ED may prevent visceral adiposity, defined as the prospective changes in WCBMI. Additional effects may be obtained among women of low alcohol, low GL, and high fibre intake

    Laudatores Temporis Acti, or Why Cosmology is Alive and Well - A Reply to Disney

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    A recent criticism of cosmological methodology and achievements by Disney (2000) is assessed. Some historical and epistemological fallacies in the said article have been highlighted. It is shown that---both empirically and epistemologically---modern cosmology lies on sounder foundations than it is portrayed. A brief historical account demonstrates that this form of unsatisfaction with cosmology has had a long tradition, and rather meagre results in the course of the XX century.Comment: 11 pages, no figures; a criticism of astro-ph/0009020; Gen. Rel. Grav., accepted for publicatio

    Acute Effects of Massage or Active Exercise in Relieving Muscle Soreness: Randomized Controlled Trial

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    Andersen, LL, Jay, K, Andersen, CH, Jakobsen, MD, Sundstrup, E, Topp, R, and Behm, DG. Acute effects of massage or active exercise in relieving muscle soreness: randomized controlled trial. J Strength Cond Res 27(12): 3352–3359, 2013—Massage is commonly believed to be the best modality for relieving muscle soreness. However, actively warming up the muscles with exercise may be an effective alternative. The purpose of this study was to compare the acute effect of massage with active exercise for relieving muscle soreness. Twenty healthy female volunteers (mean age 32 years) participated in this examiner-blind randomized controlled trial (ClinicalTrials.gov NCT01478451). The participants performed eccentric contractions for the upper trapezius muscle on a Biodex dynamometer. Delayed onset muscle soreness (DOMS) presented 48 hours later, at which the participants (a) received 10 minutes of massage of the trapezius muscle or (b) performed 10 minutes of active exercise (shoulder shrugs 10 × 10 reps) with increasing elastic resistance (Thera-Band). First, 1 treatment was randomly applied to 1 shoulder while the contralateral shoulder served as a passive control. Two hours later, the contralateral resting shoulder received the other treatment. The participants rated the intensity of soreness (scale 0–10), and a blinded examiner took measures of pressure pain threshold (PPT) of the upper trapezius immediately before treatment and 0, 10, 20, and 60 minutes after treatment 48 hours posteccentric exercise. Immediately before treatment, the intensity of soreness was 5.0 (SD 2.2) and PPT was 138 (SD 78) kPa. In response to treatment, a significant treatment by time interaction was found for the intensity of soreness (p \u3c 0.001) and PPT (p \u3c 0.05). Compared with control, both active exercise and massage significantly reduced the intensity of soreness and increased PPT (i.e., reduced pain sensitivity). For both types of treatment, the greatest effect on perceived soreness occurred immediately after treatment, whereas the effect on PPT peaked 20 minutes after treatment. In conclusion, active exercise using elastic resistance provides similar acute relief of muscle soreness as compared with that using massage. Coaches, therapists, and athletes can use either active warm-up or massage to reduce DOMS acutely, for example, to prepare for competition or strenuous work, but should be aware that the effect is temporary, that is, the greatest effects occurs during the first 20 minutes after treatment and diminishes within an hour
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