The reliability of simple progressive dies

The stamping process, of which the punching process is a major division, is one of the most important metal parts production methods in industry. Punching dies are the heart of the punching process. Die performance, as measured by the number of strokes between sharpenings and/or repairs, determines the important per part costs of die depletion and maintenance. Existing quantitative studies are principally on tool wear and punchability

Control of flower development in Arabidopsis thaliana by APETALA1 and interacting genes

Mutations in the APETALA1 gene disturb two phases of flower development, flower meristem specification and floral organ specification. These effects become manifest as a partial conversion of flowers into inflorescence shoots and a disruption of sepal and petal development. We describe the changes in an allelic series of nine apetala1 mutants and show that the two functions of APETALA1 are separable. We have also studied the interaction between APETALA1 and other floral genes by examining the phenotypes of multiply mutant plants and by in situ hybridization using probes for several floral control genes. The results suggest that the products of APETALA1 and another gene, LEAFY, are required to ensure that primordia arising on the flanks of the inflorescence apex adopt a floral fate, as opposed to becoming an inflorescence shoot. APETALA1 and LEAFY have distinct as well as overlapping functions and they appear to reinforce each other's action. CAULIFLOWER is a newly discovered gene which positively regulates both APETALA1 and LEAFY expression. All functions of CAULIFLOWER are redundant with those of APETALA1. APETALA2 also has an early function in reinforcing the action of APETALA1 and LEAFY, especially if the activity of either is compromised by mutation. After the identity of a flower primordium is specified, APETALA1 interacts with APETALA2 in controlling the development of the outer two whorls of floral organs

BLOOD AND TISSUE IDENTIFICATION OF SELECTED BIRDS AND MAMMALS, PART II: Cross Reaction Patterns of Birds and Mammals, Using Deer, Bovine, Raccoon, Chicken and Mallard Duck Antiserum, part 4

Part 4 (pp. 86-114) Mammals (Figure 10), continued Horse Human Mink Opossum Pig Porcupine. Prairie Dog Raccoon Big Horn Sheep Domestic Sheep Striped Skunk Fox Squirrel Discussio

On the effect of ensemble size on the discrete and continuous ranked probability scores

Copyright © 2008 Royal Meteorological SocietyFour recent papers have investigated the effects of ensemble size on the Brier score (BS) and discrete ranked probability score (RPS) attained by ensemble-based probabilistic forecasts. The connections between these papers are described and their results are generalized. In particular, expressions, explanations and estimators for the expected effect of ensemble size on the RPS and continuous ranked probability score (CRPS) are obtained. Copyright (c) 2008 Royal Meteorological Society

Water-Blown Polyurethane Foams Showing a Reversible Shape-Memory Effect

Water-blown polyurethane (PU) foams are of enormous technological interest as they are widely applied in various fields, i.e., consumer goods, medicine, automotive or aerospace industries. The discovery of the one-way shape-memory effect in PU foams provided a fresh impetus for extensive investigations on porous polymeric actuators over the past decades. High expansion ratios during the shape-recovery are of special interest when big volume changes are required, for example to fill an aneurysm during micro-invasive surgery or save space during transportation. However, the need to program the foams before each operation cycle could be a drawback impeding the entry of shape- memory polymeric (SMP) foams to our daily life. Here, we showed that a reversible shape-memory effect (rSME) is achievable for polyurethane water- blown semicrystalline foams. We selected commercially available crystallizable poly(ε-caprolactone)-diols of different molecular weight for foams synthesis, followed by investigations of morphology, thermal, thermomechanical and shape- memory properties of obtained compositions. Densities of synthesized foams varied from 110 to 180 kg∙m−3, while peak melting temperatures were composition-dependent and changed from 36 to 47 °C, while the melting temperature interval was around 15 K. All semicrystalline foams exhibited excellent one-way SME with shape-fixity ratios slightly above 100% and shape- recovery ratios from the second cycle of 99%. The composition with broad distribution of molecular weights of poly(ε-caprolactone)-diols exhibited an rSME of about 12% upon cyclic heating and cooling from Tlow = 10 °C and Thigh = 47 °C. We anticipate that our experimental study opens a field of systematic investigation of rSMEs in porous polymeric materials on macro and micro scale and extend the application of water-blown polyurethane foams to, e.g., protective covers with zero thermal expansion or even cushions adjustable to a certain body shape. View Full-Tex

The fraction of AGN in major merger galaxies and its luminosity dependence

We use a phenomenological model which connects the galaxy and AGN populations to investigate the process of AGN triggering through major galaxy mergers at z~0. The model uses stellar mass functions as input and allows the prediction of AGN luminosity functions based on assumed Eddington ratio distribution functions (ERDFs). We show that the number of AGN hosted by merger galaxies relative to the total number of AGN increases as a function of AGN luminosity. This is due to more massive galaxies being more likely to undergo a merger and does not require the assumption that mergers lead to higher Eddington ratios than secular processes. Our qualitative analysis also shows that to match the observations, the probability of a merger galaxy hosting an AGN and accreting at a given Eddington value has to be increased by a factor ~10 relative to the general AGN population. An additional significant increase of the fraction of high Eddington ratio AGN among merger host galaxies leads to inconsistency with the observed X-ray luminosity function. Physically our results imply that, compared to the general galaxy population, the AGN fraction among merger galaxies is ~10 times higher. On average, merger triggering does however not lead to significantly higher Eddington ratios.Comment: 11 pages, 3 figues, accepted for publication in MNRA

Properties of the Interstitial in the Diamond-Type Lattice

Linear combination of atomic orbital—molecular orbital cluster calculations using extended Hückel theory suggest that the interstitial carbon atom in diamond prefers an interstitialcy configuration. The predicted minimum-energy configuration changes with charge state, providing a possible example of the Bourgoin mechanism for athermal migration of the interstitial in the presence of ionizing radiation

The F model on dynamical quadrangulations

The dynamically triangulated random surface (DTRS) approach to Euclidean quantum gravity in two dimensions is considered for the case of the elemental building blocks being quadrangles instead of the usually used triangles. The well-known algorithmic tools for treating dynamical triangulations in a Monte Carlo simulation are adapted to the problem of these dynamical quadrangulations. The thus defined ensemble of 4-valent graphs is appropriate for coupling to it the 6- and 8-vertex models of statistical mechanics. Using a series of extensive Monte Carlo simulations and accompanying finite-size scaling analyses, we investigate the critical behaviour of the 6-vertex F model coupled to the ensemble of dynamical quadrangulations and determine the matter related as well as the graph related critical exponents of the model.Comment: LaTeX, 43 pages, 10 figures, 7 tables; substantially shortened and revised version as published, for more details refer to V1, to be found at http://arxiv.org/abs/hep-lat/0409028v

Salinity is an agent of divergent selection driving local adaptation of Arabidopsis to coastal habitats

Understanding the molecular mechanism of adaptive evolution in plants provides insights into the selective forces driving adaptation and the genetic basis of adaptive traits with agricultural value. The genomic resources available for Arabidopsis (Arabidopsis thaliana) make it well suited to the rapid molecular dissection of adaptive processes. Although numerous potentially adaptive loci have been identified in Arabidopsis, the consequences of divergent selection and migration (both important aspects of the process of local adaptation) for Arabidopsis are not well understood. Here, we use a multiyear field-based reciprocal transplant experiment to detect local populations of Arabidopsis composed of multiple small stands of plants (demes) that are locally adapted to the coast and adjacent inland habitats in northeastern Spain. We identify fitness tradeoffs between plants from these different habitats when grown together in inland and coastal common gardens and also, under controlled conditions in soil excavated from coastal and inland sites. Plants from the coastal habitat also outperform those from inland when grown under high salinity, indicating local adaptation to soil salinity. Sodium can be toxic to plants, and we find its concentration to be elevated in soil and plants sampled at the coast. We conclude that the local adaptation that we observe between adjacent coastal and inland populations is caused by ongoing divergent selection driven by the differential salinity between coastal and inland soils