Lattice Computation of a Magnetic Monopole Mass

A single magnetic monopole in pure SU(2) gauge theory is simulated on the lattice and its mass is computed in the full quantum theory. The results are relevant for our proposed realization of the dual superconductor hypothesis of confinement.Comment: 3 pages PostScript, to appear in the Proceedings of IMACS93 (St. Louis, USA, Oct. 1993). Registration numbers ITFA-93-38 (Amsterdam), DFTUZ/93/21 (Zaragoza

Chern-Simons number asymmetry from CP-violation during tachyonic preheating

We consider the creation of non-zero Chern-Simons number in a model of the early Universe, where the Higgs field experiences a fast quench at the end of inflation. We perform numerical lattice simulations in the Abelian Higgs model in 1+1 dimensions and in the SU(2)-Higgs model in 3+1 dimensions with an added effective CP-violating term. We also comment on the appropriate choice of vacuum initial conditions for classical simulations.Comment: 5 pages, 10 figures, to appear in the proceedings of SEWM2002. Modified presentation of final result. Results unchange

Sexual hormones in Achyla. V. Properties of hormone A of Achyla bisexualis

1. The hormonal coordinating mechanism of the sexual process in Achlya is briefly reviewed. 2. A technique is described for culturing the female plant of Achlya bisexualis in sufficient quantity to furnish material for the chemical study of hormone A. 3. A modification of the biological assay for hormone A is described. 4. Many of the properties of hormone A have been determined: (a) solubilities in common organic solvents, (b) adsorption, (c) stability, (d) inactivation, and (e) reactions with certain reagents. 5. A procedure is described whereby enormous enrichment of the active principle has been achieved

Simulations of Cold Electroweak Baryogenesis: Finite time quenches

The electroweak symmetry breaking transition may supply the appropriate out-of-equilibrium conditions for baryogenesis if it is triggered sufficiently fast. This can happen at the end of low-scale inflation, prompting baryogenesis to occur during tachyonic preheating of the Universe, when the potential energy of the inflaton is transfered into Standard Model particles. With the proper amount of CP-violation present, the observed baryon number asymmetry can be reproduced. Within this framework of Cold Electroweak Baryogenesis, we study the dependence of the generated baryon asymmetry on the speed of the quenching transition. We find that there is a separation between ``fast'' and ``slow'' quenches, which can be used to put bounds on the allowed Higgs-inflaton coupling. We also clarify the strong Higgs mass dependence of the asymmetry reported in a companion paper (hep-ph/0604263).Comment: 18 pages, 20 figure

W-Particle Distribution in ElectroWeak Tachyonic Pre-Heating

Results are presented of a numerical study of the distribution of W-bosons generated in a tachyonic electroweak pre-heating transitionComment: Contribution to Strong and ElectroWeak Matter 2002, 5 page

Xanthurenic acid and its rôle in the trytophane metabolism of pyroxidine-deficient rats

In a previous publication (1) the isolation of a green pigment from the urine of pyridoxine-deficient rats was described. The green pigment was shown to be the product of a reaction between ferric ammonium sulfate or other ferric salts and a compound whose nature was unknown. This compound has now been isolated in crystalline form. It is a yellow pigment and has been identified as xanthurenic acid

Heavy cosmic strings

We argue that cosmic strings with high winding numbers generally form in first-order gauge symmetry breaking phase transitions, and we demonstrate this using computer simulations. These strings are heavier than single-winding strings and therefore more easily observable. Their cosmological evolution may also be very different.Comment: 4 pages, updated to match the published versio

A new method for the separation of androgens from estrogens and for the partition of estriol from the estrone-estradiol fraction: with special reference to the identification and quantitative microdetermination of estrogens by ultraviolet absorption spectrophotometry

It is recognized generally that a qualitative and quantitative knowledge of the excretion pattern of the urinary estrogens is one index to an understanding of the functional activity of the ovary and adrenal cortex. Obviously, such determinations may be useful also in evaluating the normal and abnormal functions of other physiologically related endocrine glands as well as of organs like the liver and kidneys. The clinical applications of these data are self-evident. Various attempts have been made to circumvent the notoriously inaccurate values which have been obtained for the urinary estrogens by a variety of bioassay methods and calorimetric techniques (1, 2). The acknowledged shortcomings of these methods have led us to investigate the application of ultraviolet absorption spectrophotometry to the quantitative determination of the urinary estrogens in an attempt to develop an objective physical method for their accurate determination. It is known that the infra-red portion of the spectrum yields more differentially characteristic curves, but those of the ultraviolet range are more readily obtainable, and consequently better adapted to clinical use. This communication is concerned with studies of the following aspects of the problem: (1) spectrophotometric identification and quantitative micro determination of crystalline estrogens; (2) detection by spectrophotometric assay of gross errors in current methods for extraction and partition of estrogens; (3) studies on the ultraviolet absorption of substances comprising the background material; (4) separation of the phenolic estrogens from the so called neutral steroid fraction; (5) separation of urinary estrogens from other urinary phenolic substances by steam distillation; (6) micro-Girard separation of estrone from estradiol; (7) an essentially new method for the extraction and partition of crystalline estrone, estradiol, and estriol, and their quantitative assay by ultraviolet spectrophotometry

Complex, Dynamic Combination of Physical, Chemical and Nutritional Variables Controls Spatio-Temporal Variation of Sandy Beach Community Structure

Sandy beach ecological theory states that physical features of the beach control macrobenthic community structure on all but the most dissipative beaches. However, few studies have simultaneously evaluated the relative importance of physical, chemical and biological factors as potential explanatory variables for meso-scale spatio-temporal patterns of intertidal community structure in these systems. Here, we investigate macroinfaunal community structure of a micro-tidal sandy beach that is located on an oligotrophic subtropical coast and is influenced by seasonal estuarine input. We repeatedly sampled biological and environmental variables at a series of beach transects arranged at increasing distances from the estuary mouth. Sampling took place over a period of five months, corresponding with the transition between the dry and wet season. This allowed assessment of biological-physical relationships across chemical and nutritional gradients associated with a range of estuarine inputs. Physical, chemical, and biological response variables, as well as measures of community structure, showed significant spatio-temporal patterns. In general, bivariate relationships between biological and environmental variables were rare and weak. However, multivariate correlation approaches identified a variety of environmental variables (i.e., sampling session, the C:N ratio of particulate organic matter, dissolved inorganic nutrient concentrations, various size fractions of photopigment concentrations, salinity and, to a lesser extent, beach width and sediment kurtosis) that either alone or combined provided significant explanatory power for spatio-temporal patterns of macroinfaunal community structure. Overall, these results showed that the macrobenthic community on Mtunzini Beach was not structured primarily by physical factors, but instead by a complex and dynamic blend of nutritional, chemical and physical drivers. This emphasises the need to recognise ocean-exposed sandy beaches as functional ecosystems in their own right

On the design of a real-time volume rendering engine

An architecture for a Real-Time Volume Rendering Engine (RT-VRE) is given, capable of computing 750 × 750 × 512 samples from a 3D dataset at a rate of 25 images per second. The RT-VRE uses for this purpose 64 dedicated rendering chips, cooperating with 16 RISC-processors. A plane interpolator circuit and a composition circuit, both capable to operate at very high speeds, have been designed for a 1.6 micron VLSI process. Both the interpolator and composition circuit are back from production. They have been tested and both complied with our specifications