VLBI Observations of a Complete Sample of Radio Galaxies V. 3C346 and 4C31.04: two Unusual CSS Sources

We present observations at 1.7 and 8.4 GHz of two Compact Steep Spectrum (CSS) sources from a complete sample of low-intermediate power radio galaxies. 3C346 shows an asymmetric structure with a one-sided ``jet'' and ``hot spot''. Present observations suggest that the classification of this source as a CSS is inappropriate, and that it is a common radio galaxy at a small angle to the line of sight. Its properties are in agreement with the predictions of unified schemes models. 4C31.04 shows more complex structure with the possibility of a centrally located flat spectrum core in between two close lobes. We suggest that this source could be a low redshift Compact Symmetric Object.Comment: 15 pages, LATEX, uuenconde ps figures To be published in the Astrophysical Journal, October 20th issu

Species sensitivity of zeolite minerals for uptake of mercury solutes

The uptake of inorganic Hg2+ and organometallic CH3Hg+ from aqueous solutions by 11 different natural zeolites has been investigated using a batch distribution coefficient (Kd) method and supported by a preliminary voltammetric study. The effect of mercury concentration on theKd response is shown over an environmentally appropriate concentration range of 0.1-5 ppm inorganic and organometallic Hg using a batch factor of 100 ml g−1 and 20 h equilibration. Analcime and a Na-chabazite displayed the greatest methylmercury uptakes (Kd values at 1.5 ppm of 4023 and 3456, respectively), with mordenite as the smallest at 578. All uptake responses were greater for methylmercury than for the inorganic mercuric nitrate solutions, suggesting a distinctive sensitivity of zeolites to reaction with different types of solute species. It is likely that this sensitivity is attributable to the precise nature of the resultant Hg-zeolite bonds. Additionally, both the Si-Al ratio and the Na content of the initial natural zeolite samples are shown to influence the Kd responses, with positive correlations between Kd and Na content for all zeolites excluding mordenite

Magnetoelectric birefringence revisited

Electromagnetic wave propagation inside isotropic material media characterized by dielectric coefficients $\varepsilon_{\mu\nu}(E,B)$ and $\mu_{\mu\nu}(E,B)$ is examined. The regime of the eikonal approximation is considered. The Hadamard method of field disturbances is used and the dispersion relations are obtained by solving the Fresnel equation. Some applications of the formalism are presented. Particularly, birefringence phenomena induced by applied external fields are derived and discussed. It is shown that magnetoelectric birefringence effect can occur even without the presence of Kerr and Cotton-Mouton effects, provided the physical system satisfies certain conditions.Comment: 9 pages, 1 figure, LaTe

The Einstein 3-form G_a and its equivalent 1-form L_a in Riemann-Cartan space

The definition of the Einstein 3-form G_a is motivated by means of the contracted 2nd Bianchi identity. This definition involves at first the complete curvature 2-form. The 1-form L_a is defined via G_a = L^b \wedge #(o_b \wedge o_a). Here # denotes the Hodge-star, o_a the coframe, and \wedge the exterior product. The L_a is equivalent to the Einstein 3-form and represents a certain contraction of the curvature 2-form. A variational formula of Salgado on quadratic invariants of the L_a 1-form is discussed, generalized, and put into proper perspective.Comment: LaTeX, 13 Pages. To appear in Gen. Rel. Gra

Induction of Parturition in Beef Cattle With Dexamethasone

In recent years many reports have shown that synthetic glucocorticoids such as dexamethasone (DXMS) and flumethasone will induce parturition in cattle when injected intramuscularly during various stages of gestation. A study was conducted at South Dakota State University to determine, under field conditions, the effectiveness of DXMS coupled with estradiol on the precision of parturition induction, the incidence of retained placentas and subsequent reproductive performance of beef cows

The Bologna Complete Sample of Nearby Radio Sources

We present a new, complete, sample of 95 radio sources selected from the B2 and 3CR catalogues, with z < 0.1. Since no selection effect on the core radio power, jet velocity, or source orientation is present, this sample is well suited for statistical studies. In this first paper we present the observational status of all sources on the parsec (mas) and kiloparsec (arcsec) scale; we give new parsec-scale data for 28 sources and discuss their parsec-scale properties. Combining these data with those in the literature, information on the parsec-scale morphology is available for a total of 53 radio sources with different radio power and kpc-scale morphology. We investigate their properties. We find a dramatically higher fraction of two-sided sources in comparison to previous flux limited VLBI surveys.Comment: 29 pages, 21 figures - ApJ in press (10 Jan 2005 issue

Geothermal energy in the UK: The life-cycle environmental impacts of electricity production from the United Downs Deep Geothermal Power project

The UK is rich in heat-producing granites, especially in the county of Cornwall, suggesting the potential for energy production with low environmental footprint. The United Downs Deep Geothermal Power (UDDGP) project aims to demonstrate the technical and commercial viability to produce electricity from the Cornish geothermal resource, exploiting the natural permeability of a significant deep structural fracture zone known as the Porthtowan Fault Zone. Drilling of the first well started at the end of 2018, and the plant is expected to be operational by mid-2020. A relevant question is whether deep geothermal energy is truly environmentally benign. This article presents a comprehensive and detailed Life Cycle Assessment study that i) identifies the main life-cycle sources of environmental impacts for the production of electricity in the UDDGP plant; ii) investigates the effects on the environmental impacts of significant uncertainties surrounding the project, such as availability of geothermal fluid and configuration of the power plant, and iii) compares the performance of the UDDGP operation, and by extension of the putative geothermal energy production in the UK, with other key energy sources in the country. The life cycle inventory relies on a combination of site-specific data for wells construction and literature data for above-surface facilities and stimulation techniques. We validated our model by comparing climate change impacts of UDDGP with those reported by other studies on enhanced geothermal systems. Our results show that the greatest portion of environmental impacts originates from the construction phase (primarily due to steel for wells casing and diesel used during drilling), whilst the scenario analysis demonstrates that increasing installed capacity and cogenerating heat and power are the most effective strategies for improving the environmental performance. Our analysis also suggests that the environmental impacts may increase by ∼35% if stimulation techniques are required to increase the geothermal wells productivity. Compared to alternative energy sources, in the category climate change, UDDGP performs better than solar energy and is comparable with wind and nuclear. It is shown that the environmental benefits of geothermal energy are not straightforward and that a number of trade-offs needs to be considered when other impact categories are quantified

Life-cycle Inventory data and impacts on electricity production at the United Downs Deep Geothermal Power project in the UK

This data article supports the research article “Geothermal energy in the UK: the life-cycle environmental impacts of electricity production from the United Downs Deep Geothermal Power project”. The article reports inventory data, primarily on the construction of the geothermal wells, that is not reported in the main article, and the complete, disaggregated numerical values of the life-cycle environmental impacts reported only in part and in graphical form in the research article. The article also includes data supporting comparative analyses between deep geothermal energy and other energy technologies in the UK, and between the impacts of the construction of wells in a deep and conventional power plant

Charles Darwin and Coral Reefs

Christmas Day of the year eighteen hundred and thirty-one found the young Charles Darwin making his final preparations for the long voyage which laid the foundations of his scientific career. He was then in his twenty-third year, and had just taken his degree at Cambridge. His keen interest in sport and in the pursuit of outdoor studies in natural history robbed him of any academic distinction, and his place as tenth on the list of the pass graduates gave no clue to those rare qualities of mind which afterwards gained him a secure place among the immortals. Darwin's interest in natural history was manifested in his boyhood days, and was fostered by the two years which he devoted to the study of medicine at Edinburgh. A further opportunity for scientific studies was given to him after graduation by his friendship with Henslow and Sedgwick. It was the botanist Henslow who secured for him the position of naturalist on the Beagle, and it was Sedgwick who fostered that love for geology which led him to give it such a prominent place during his voyage on the Beagle.