Fission studies with 140 MeV α\bm{\alpha}-Particles

Binary fission induced by 140 MeV $\alpha$-particles has been measured for $^{\rm nat}$Ag, $^{139}$La, $^{165}$Ho and $^{197}$Au targets. The measured quantities are the total kinetic energies, fragment masses, and fission cross sections. The results are compared with other data and systematics. A minimum of the fission probability in the vicinity $Z^2/A=24$ is observed.Comment: 4 figures, 2 table

Offshore oil and gas platforms as stepping stones for expansion of coral communities: a molecular genetic analysis

The northern Gulf of Mexico (GOM) is one of the most productive oil and gas exploration areas in the world, currently containing approximately 3,800 offshore platforms. These platforms serve as artificial reefs in shallow water, which until their introduction was nearly devoid of shallow hard substrata. The question is raised whether this newly available substrate could help expand coral populations in the GOM. In this study, I examined adult scleractinian corals on oil and gas platforms in the northern GOM, in the vicinity of the Flower Garden Banks (FGB; approximately 180 km SE of Galveston, Texas) and attempted to determine the degree of genetic affinity among the natural and platform populations there. Adult coral tissue samples were collected from seven platforms surveyed in the region of the FGB at a depth range of 0-30 m. The three most abundant scleractinian, hermatypic species were sampled: Madracis decactis, Diploria strigosa, and Montastraea cavernosa. Genetic variation was revealed by Amplified Fragment Length Polymorphisms (AFLPs), a DNA-fingerprinting technique based on the polymerase chain reaction (PCR). This tool successfully distinguished between closely related colonies derived from populations on different platforms and on the two Flower Garden Banks. AMOVA analyses indicated that the East and West FGB were homogeneous for Madracis decactis and Diploria strigosa; however, the Montastraea cavernosa populations at the two banks were significantly different. Randomized data sets of two Madracis decactis populations were run with AFLPOP using a minimum log-likelihood difference of zero and one. These analyses determined that a log-likelihood difference of one is a more conservative and more reliable option, and all subsequent analyses were run using this setting. AFLPOP analyses showed that Montastraea cavernosa at the two banks was highly self-contained, indicating a possible high degree of self-seeding with regard to this species. It appears that Madracis decactis, a brooding species, is highly effective at dispersing to neighboring habitats over distances of kms to tens of kms. By comparison, Diploria strigosa and Montastraea cavernosa, both broadcasting species, are not. They may be more effective at larger scale dispersal, but this remains to be demonstrated

Cross-sections of spallation residues produced in 1.A GeV 208Pb on proton reactions

Spallation residues produced in 1 GeV per nucleon $^{208}$Pb on proton reactions have been studied using the FRagment Separator facility at GSI. Isotopic produc- tion cross-sections of elements from $_{61}$Pm to $_{82}$Pb have been measured down to 0.1 mb with a high accuracy. The recoil kinetic energies of the produced fragments were also determined. The obtained cross-sections agree with most of the few existing gamma-spectroscopy data. Data are compared with different intra nuclear-cascade and evaporation-fission models. Drastic deviations were found for a standard code used in technical applications.Comment: 4 pages, 3 figures, accepted for publication in Phys. Rev. Lett. Revised version May 12, 200

Spallation Residues in the Reaction 56Fe + p at 0.3, 0.5, 0.75, 1.0 and 1.5 A GeV

The spallation residues produced in the bombardment of 56}Fe at 1.5, 1.0, 0.75, 0.5 and 0.3 A GeV on a liquid-hydrogen target have been measured using the reverse kinematics technique and the Fragment Separator at GSI (Darmstadt). This technique has permitted the full identification in charge and mass of all isotopes produced with cross-sections larger than 10^{-2} mb down to Z=8. Their individual production cross-sections and recoil velocities at the five energies are presented. Production cross-sections are compared to previously existing data and to empirical parametric formulas, often used in cosmic-ray astrophysics. The experimental data are also extensively compared to different combinations of intra-nuclear cascade and de-excitation models. It is shown that the yields of the lightest isotopes cannot be accounted for by standard evaporation models. The GEMINI model, which includes an asymmetric fission decay mode, gives an overall good agreement with the data. These experimental data can be directly used for the estimation of composition modifications and damages in materials containing iron in spallation sources. They are also useful for improving high precision cosmic-ray measurements.Comment: Submited to Phys. Rev. C (10/2006

Green Plants in the Red: A Baseline Global Assessment for the IUCN Sampled Red List Index for Plants

Plants provide fundamental support systems for life on Earth and are the basis for all terrestrial ecosystems; a decline in plant diversity will be detrimental to all other groups of organisms including humans. Decline in plant diversity has been hard to quantify, due to the huge numbers of known and yet to be discovered species and the lack of an adequate baseline assessment of extinction risk against which to track changes. The biodiversity of many remote parts of the world remains poorly known, and the rate of new assessments of extinction risk for individual plant species approximates the rate at which new plant species are described. Thus the question ‘How threatened are plants?’ is still very difficult to answer accurately. While completing assessments for each species of plant remains a distant prospect, by assessing a randomly selected sample of species the Sampled Red List Index for Plants gives, for the first time, an accurate view of how threatened plants are across the world. It represents the first key phase of ongoing efforts to monitor the status of the world’s plants. More than 20% of plant species assessed are threatened with extinction, and the habitat with the most threatened species is overwhelmingly tropical rain forest, where the greatest threat to plants is anthropogenic habitat conversion, for arable and livestock agriculture, and harvesting of natural resources. Gymnosperms (e.g. conifers and cycads) are the most threatened group, while a third of plant species included in this study have yet to receive an assessment or are so poorly known that we cannot yet ascertain whether they are threatened or not. This study provides a baseline assessment from which trends in the status of plant biodiversity can be measured and periodically reassessed

Building light nuclei from neutrons, protons, and pions

In these lectures I first explain, in a rather basic fashion, the construction of effective field theories. I then discuss some recent developments in the application of such theories to two- and three-nucleon systems.Comment: 54 pages, uses czjphys.cls. Lectures given at 14th Summer School "Understanding the Structure of Hadrons", Prague, July 2001. To appear in Czechoslovak Journal of Physic

Search for heavy neutrinos mixing with tau neutrinos

We report on a search for heavy neutrinos (\nus) produced in the decay D_s\to \tau \nus at the SPS proton target followed by the decay \nudecay in the NOMAD detector. Both decays are expected to occur if \nus is a component of $\nu_{\tau}$.\ From the analysis of the data collected during the 1996-1998 runs with $4.1\times10^{19}$ protons on target, a single candidate event consistent with background expectations was found. This allows to derive an upper limit on the mixing strength between the heavy neutrino and the tau neutrino in the \nus mass range from 10 to 190 $\rm MeV$. Windows between the SN1987a and Big Bang Nucleosynthesis lower limits and our result are still open for future experimental searches. The results obtained are used to constrain an interpretation of the time anomaly observed in the KARMEN1 detector.\Comment: 20 pages, 7 figures, a few comments adde

The Vegetarian Magazine May 1900

Periodical discussing the vegetarian lifestyle and recipes. Includes the regular column Of Interest to the Housewife. Discusses ways of serving bleached apricots, corn meal, and rice.https://knowledge.e.southern.edu/foodiesguide-1890/1082/thumbnail.jp

Using Mobile Technologies to Enhance Accessibility and Inclusion in Field-Based Learning

The relevance of field education in the geosciences has been subject to increasing scrutiny, in part due to the exclusionary nature of traditional field practices that require independent work and physical agility. As an alternative, this article presents strategies for increasing accessibility and inclusion in collaborative field-based education through the use of mobile technologies. We present a series of examples to show how the use of mobile technologies in the field can enable collaborative observation, data collection, data sharing, and interpretation. The strategies developed in these examples provide equitable access to instruction, peer engagement, and participation in every field exercise. We suggest that technological approaches to accessibility and inclusion in the field can facilitate opportunities for all students to gain field experiences that are an important component of geoscience education

The Vegetarian Magazine July 1900

Periodical discussing the vegetarian lifestyle and recipes. Includes the regular column Of Interest to the Housewife. Recipes include dumpling soup, cream of peas, tomato salad, and cucumber salad.https://knowledge.e.southern.edu/foodiesguide-1890/1068/thumbnail.jp