Use of Geographic Information System Technology to Assess Vulnerability to Shallow Groundwater Contamination.

Geographic Information System (GIS) technology was used to develop a local scale screening procedure for assessing shallow ground water\u27s vulnerability to nitrate contamination. The procedure was based on the spatial distribution of ten key physical and chemical properties of soils. Both flow characteristics and attenuation capabilities of soils were incorporated into the assessment. Land surface areas were classified by the GIS to show the level of vulnerability present at a site as a result of existing natural conditions. The procedure produced a Vulnerability Index (VI), and resulted in VI ranging from 4.98 to 6.72 for the study area (with ten indicating the highest vulnerability). Procedure evaluation involved shallow water well sampling for nitrates, and the correlation of VI values with nitrate concentrations. Four GIS-based approaches were used to evaluate the procedure\u27s reliability. Vulnerability was examined as a point value (at the wellhead), and within a wellhead buffer area of three different sizes: 400- and 800-meter radius, and a custom-shaped area upgradient of the wellhead of equal area to the 800-meter area. Sampling was conducted in the Big Creek sub-basin of the Tangipahoa River in Southeastern Louisiana. Wells located on sixteen dairies and ten residential (non-dairy) sites were tested for nitrates and phosphates. Bi-weekly sampling was conducted during the summer, 1993 and winter, 1994. Water quality results indicated that 84.7 percent of all samples had ground water nitrate concentrations less than 1 mg-N/L. Nineteen of 26 sites had concentrations that remained below this level. Higher concentrations were observed at seven sites. The highest concentrations observed were 12.95 Mg-N/L (dairy site) and 8.57 mg-N/L (residential site). Phosphates were not detected at any sampling site. Comparisons of VI to nitrate concentrations by linear regression analysis indicated the procedure was moderately reliable. Area assessments consistently provided better correlation between vulnerability and nitrate occurrence than did the point assessment. The best correlation between VI and maximum nitrate concentrations (R of 0.454) was obtained for the custom buffered approach

Attosecond time-resolved photoelectron holography

Ultrafast strong-field physics provides insight into quantum phenomena that evolve on an attosecond time scale, the most fundamental of which is quantum tunneling. The tunneling process initiates a range of strong field phenomena such as high harmonic generation (HHG), laser-induced electron diffraction, double ionization and photoelectron holography—all evolving during a fraction of the optical cycle. Here we apply attosecond photoelectron holography as a method to resolve the temporal properties of the tunneling process. Adding a weak second harmonic (SH) field to a strong fundamental laser field enables us to reconstruct the ionization times of photoelectrons that play a role in the formation of a photoelectron hologram with attosecond precision. We decouple the contributions of the two arms of the hologram and resolve the subtle differences in their ionization times, separated by only a few tens of attoseconds

The circle of Gánovce. Natural history of an endocast

The natural endocranial cast of Gánovce was found in Slovakia in 1926, and then stored in the National Museum (Národní Muzeum) of Prague. The endocast was extensively studied by Emanuel Vlček (1925-2006), mostly during the 50s and 60s of the past century (e.g., Vlček, 1949, 1953, 1955, 1969), with a large set of analytical tools including radiographic and biochemical sur- veys, and outline shape analysis. He recognized the Neanderthal morphology of the cast, which was dated to 105 ka and which has an estimated volume of 1320cc. In particular, Vlček noticed a similarity with specimens such as Krapina 3, Gibraltar 1 and Saccopastore 1. In fact, these three specimens all display a similar overall cra- nial anatomy, being possibly representatives of an “early and small-brained” Neanderthal morpho- type (Bruner & Manzi, 2006, 2008)

Solar High-energy Astrophysical Plasmas Explorer (SHAPE). Volume 1: Proposed concept, statement of work and cost plan

The concept of the Solar High-Energy Astrophysical Plasmas Explorer (SHAPE) is studied. The primary goal is to understand the impulsive release of energy, efficient acceleration of particles to high energies, and rapid transport of energy. Solar flare studies are the centerpieces of the investigation because in flares these high energy processes can be studied in unmatched detail at most wavelenth regions of the electromagnetic spectrum as well as in energetic charged particles and neutrons

Motivation for Active Aging: Results of a Pilot Study

The current research explores the question whether activity on the part of older people can be explained, in part, by a general motivation to be active that cuts across various forms of activity. One premise is that motivation defined as “personal interest or desire” is one of a number of forces that contributes to participation in an activity. A further premise is that a distinction may be made between motivation that is specific to a particular activity and general motivation to be active. A general motive to be active may help to explain specific forms of activity. Further, a general motive to be active may also help to explain the number of forms of activity in which people engage

Sonata for Flute and Piano

1 score (28 p.) ; 1 finale (32 p.

The energetics of the gradual phase

Reseachers compare results with those in the chapter by Moore et al. (1980), who reached five main conclusions about the gradual phase: (1) the typical density of the soft X-ray emitting plasma is between 10 to the 11th power and 10 to the 12th power cm-3 for compact flares and between 10 to the 10th power and 10 to the 11th power cm-3 for a large-area flare; (2) cooling is by conduction and radiation in roughly equal proportions; (3) continual heating is needed in the decay phase of two-ribbon flares; (4) continual heating is probably not needed in compact events; (5) most of the soft-X-ray-emitting plasma results from chromospheric evaporation. The goal was to reexamine these problems with the data from the Solar Maximum Mission (SMM) and other supporting instruments as well as to take advantage of recent theoretical advances. SMM is capable of measuring coronal temperatures more accurately and with a better cadence than has been possible before. The SMM data set is also unique in that the complete transit of an active region was observed, with soft X-ray and UV images being taken every few minutes. Researcher's were therefore able to establish the pre-flare conditions of the region and see whether anything has changed as a result of the flare. The assumptions made in attempting to determine the required plasma parameters are described. The derived parameters for the five prime flares are presented, and the role of numerical simulations is discussed