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G Moser

Publications and source records attributed to G Moser.

At least 19 recordsLinked to original sources
PubMed2006

Two-loop field theory and nonasymptotic properties of the dynamical model for the lambda transition in 3He-4He mixtures.

Model F' introduced by Siggia and Nelson [Phys. Rev. B 15, 1427 (1977)] describes the critical dynamics of 3He-4He mixtures near the superfluid transition. Using the minimal subtraction scheme this model is renormalized within dynamical field theory. The dynamic zeta functions needed for the nonasymptotic flow properties are presented in two-loop order. The fixed points are discussed and the stable fixed points are identified. The transition to limiting models contained in model F' is shown analytically by performing the corresponding limits and numerically by calculating the nonlinear flow. These results are the basis for further experimental comparison of the transport coefficents in 3He-4He mixtures at higher concentrations including the tricritical point.

Journal Article↗
PubMed2006

European evidence based consensus on the diagnosis and management of Crohn's disease: special situations.

This third section of the European Crohn's and Colitis Organisation (ECCO) Consensus on the management of Crohn's disease concerns postoperative recurrence, fistulating disease, paediatrics, pregnancy, psychosomatics, extraintestinal manifestations, and alternative therapy. The first section on definitions and diagnosis reports on the aims and methods of the consensus, as well as sections on diagnosis, pathology, and classification of Crohn's disease. The second section on current management addresses treatment of active disease, maintenance of medically induced remission, and surgery of Crohn's disease.

Anti-Bacterial Agents↗
PubMed2005

Critical dynamics of diluted relaxational models coupled to a conserved density.

We consider the influence of quenched disorder on the relaxational critical dynamics of a system characterized by a nonconserved order parameter coupled to the diffusive dynamics of a conserved scalar density (model C). Disorder leads to model A critical dynamics in the asymptotics; however, it is the effective critical behavior that is often observed in experiments and in computer simulations, and this is described by the full set of dynamical equations of diluted model C. Indeed, different scenarios of effective critical behavior are predicted.

Journal Article↗
PubMed2005

Critical dynamics of stochastic models with two conserved densities (model C' ).

We calculate the field-theoretic functions of the generalized dynamical model C(*') , where two conserved secondary densities are coupled to a nonconserved complex order parameter (OP), in two-loop order. A transformation to "orthogonalized" densities can be performed where only one secondary density with nontrivial static coupling to the OP exists while the second one remains Gaussian. The secondary densities remain dynamically coupled by the nondiagonal diffusion coefficent. General relations for the field-theoretic functions allow us to relate the asymptotic critical properties of model C(*') to the simpler model C(*) with only one conserved density coupled to the OP. The nonasymptotic properties, however, differ as can be seen from the flow of the dynamic parameters, which is presented for the case of a real OP with componets n=1,2,3 .

Journal Article↗
PubMed2004

Critical dynamics of stochastic models with energy conservation (model C).

We calculate the field-theoretic functions of the generalized dynamical model C*, in which a conserved secondary density is coupled to a nonconserved complex order parameter, in two-loop order. We show that the fixed points in this extended model are equal to the fixed points obtained in model C with a real order parameter, which has been introduced by Halperin, Hohenberg, and Ma. Our results correct long-standing errors in the field-theoretic functions in model C published by several authors leading also to different fixed point values w* for the ratio of the two time scales involved. The stability regions of the fixed points, which remained partially unclear, considered in a "phase diagram"--whose axes are the spatial dimension d and number of order parameter components n--are now clarified. Especially an anomalous region found by previous authors, in which the scaling properties remained unsolved, does not exist. There are only two regions: one with a finite fixed point w* where the dynamical exponent z of the order parameter is z=2+alpha/nu and another region where w*=0 and z is equal to the model A value.

Journal Article↗
PubMed2004

Effects of season of birth on reproduction in contemporary humans: brief communication.

BACKGROUND: At high latitudes the external environment varies with season, and therefore the season of birth may contribute to the developmental processes during the perinatal period. METHODS: We investigated the association between birth season and measures of reproductive performance (offspring count, percentage childless individuals) in a contemporary sample of women and men. RESULTS: In the male sample (n = 2342), men born in autumn had fewer offspring (mean 1.4 versus 1.62; P < 0.01) and a higher probability of remaining childless (32.6% versus 25.6%; P = 0.01) than men born in spring. The photoperiod at a male's birth was significantly positively correlated with his subsequent offspring count (P = 0.023). In the female sample, an association between birth season and reproduction was not found. CONCLUSIONS: We assume that in men, among other seasonal factors, pre- or perinatal photoperiod might be involved in the underlying physiological mechanism.

Family Characteristics↗
PubMed2004

Brief communication: birth month influences reproductive performance in contemporary women.

BACKGROUND: Season of birth has been reported to affect later reproduction in samples of pre-modern women and contemporary men. METHODS: To examine whether the effect of birth date is also valid in contemporary women, we investigated the association between birth month and measures of reproductive performance (number of live-born children, % childless individuals) in a representative sample of contemporary Austrian women. RESULTS: Among reproducing women, birth month is significantly associated with the number of live-born children (n = 2839, P = 0.032). On average, women born in summer months have fewer children than women born during the remainder of the year. No association between birth month and the percentage of childless individuals was found. CONCLUSIONS: As has been reported in pre-modern women, month of birth also appears to affect later reproduction in contemporary women.

Austria↗
PubMed2003

Critical dynamics of model C resolved.

We analyze the field theoretic functions of the dynamical model C in two-loop order. Our results correct long-standing errors in these functions published by several authors. We discuss, in particular, the fixed points for the ratio w* of the two time scales involved, as well as their stability. The regions of the "phase diagram," whose axes are the spatial dimension d and number of order parameter components n, correspond to these fixed points; previous authors have found, in addition, an anomalous region in which the scaling properties were unclear. We show that such an anomalous region does not exist. There are only two regions: one with a finite fixed-point w* where the dynamical exponent z=2+alpha/nu, and another where w*=0 and z is equal to the model A value. We show how the one-loop result is recovered from the two-loop result in the limit epsilon=4-d going to zero.

Journal Article↗
PubMed2003

A comparitive study of ammonia-oxidizing bacteria in lab-scale industrial wastewater treatment reactors.

The diversity and community structure of the beta-proteobacterial ammonia oxidising bacteria (AOB) in a range of different lab-scale industrial wastewater treatment reactors were compared. Three of the reactors treat waste from mixed domestic and industrial sources whereas the other reactor treats waste solely of industrial origin. PCR with AOB selective primers was combined with denaturing gradient ge electrophoresis to allow comparative analysis of the dominant AOB populations and the phylogenetic affiliation of the dominant AOB was determined by cloning and sequencing or direct sequencing of bands excised from DGGE gels. Different AOB were found within and between different reactors. All AOB sequences identified were grouped within the genus Nitrosomonas. Within the lab-scale reactors there appeared to be selection for a low diversity of AOB and predominance of a single AOB population. Furthermore, the industrial input in both effluents apparently selected for salt tolerant AOB, most closely related to Nitrosococcus mobilis and Nitrosomonas halophila.

Ammonia↗
PubMed2002

Dynamic critical behavior near the superfluid transition in 3He-4He mixtures in two loop order.

We calculated in two loop order the field theoretic renormalization group functions taking into account the decomposition of the dynamical vertex functions into the static vertex functions and genuine dynamical parts. The observation of this nonperturbative structure simplifies the theoretical expressions obtained by perturbation theory considerably and makes tractable a complete two loop calculation of the critical dynamics near the superfluid transition of 3He-4He mixtures (model F'). As a result, we obtain various transport coefficients, which govern the nonasymptotic and nonuniversal temperature dependence. We also correct long-standing results for the critical dynamics of the superfluid transition in pure 4He (model F) and for the dynamics of structural or magnetic phase transitions (model C).

Journal Article↗
PubMed2001

Extracorporeal photochemotherapy in patients with steroid-dependent Crohn's disease: a prospective pilot study.

BACKGROUND: Extracorporeal photochemotherapy has been proven effective in selected T-cell mediated diseases. AIM: To evaluate the safety and efficacy of extracorporeal photochemotherapy in patients with steroid-dependent Crohn's disease by an open, monocentric trial in three phases of 24 weeks each. METHODS: In phase 1 standardized steroid tapering was initiated in patients with a history of steroid-dependent Crohn's disease. Those with a prospectively evaluated maintenance dose of at least 10 mg/day prednisolone continued steroid-withdrawal under the application of extracorporeal photochemotherapy in phase 2. The duration of remission or response was followed during phase 3. Colonic tissue bioptically obtained before and after extracorporeal photochemotherapy was studied by immunofluorescence microscopy for the presence of photoadduct positive cells. RESULTS: Out of 24 patients included in phase 1, 10 entered phase 2 for extracorporeal photochemotherapy. Four subjects achieved remission and four others response. Significant reductions in serum C-reactive protein levels and intestinal permeability were measured, as well as increases in quality of life and plasma adrenocorticotropic hormone levels. No major side-effects were observed. Remission remained stable in three out of four patients during phase 3. In three patients, positive nuclear stainings of photoadducts were detected in colonic mononuclear cells after extracorporeal photochemotherapy. CONCLUSIONS: Extracorporeal photochemotherapy represents a safe steroid-sparing approach in patients with Crohn's disease and is associated with intestinal homing of photopheresed cells.

Adult↗
PubMed2001

Azathioprine treatment and male fertility in inflammatory bowel disease.

BACKGROUND & AIMS: Long-term treatment with azathioprine (AZA) is well established in inflammatory bowel disease (IBD). AZA is metabolized to 6-mercaptopurine (6-MP), which interacts in purine metabolism and is therefore considered to have mutagenic potentials. This is the first study to examine the influence of AZA on semen quality. METHODS: Semen quality was examined and compared with World Health Organization (WHO) standards regarding sperm density, motility, morphology, ejaculate volume, and total sperm count in 23 IBD patients treated with AZA. In 10 of these patients, a semen sample was assessed before and during AZA treatment; in another 5, semen analysis was performed twice during at least 2 years of AZA therapy. RESULTS: In 18 patients treated with 1.5-2 mg/kg AZA daily for at least 3 months but without sulfasalazine, sperm density was 94 +/- 84 Mio/mL (94% within WHO standard), motility was 60% +/- 20% (67% within WHO standard), the proportion of sperm with normal morphology was 44% +/- 21% (67% within WHO standard), ejaculate volume was 3.4 +/- 1.5 mL (89% within WHO standard), and total sperm count was 297 +/- 272 Mio (94% within WHO standard). No changes in semen parameters were noted after 11 +/- 5 months of AZA administration or during long-term treatment (49 +/- 14 months). Sulfasalazine administration in 5 patients was associated with markedly reduced semen morphology. During the study period, 6 patients fathered 7 healthy children. CONCLUSIONS: Our data show that AZA does not reduce semen quality and thereby male fertility in IBD.

Adolescent↗