What Goes on Here

Americans, like most human beings, recoil at the thought of war, and the idea of another war, a World War III, seems repulsive beyond description. However, here and there in our country, there are voices which are saying that we should engage in a so-called preventive war against Russia

Hydrogeology and Hydrogeochemistry of the Shallow Alluvial Aquifer Zone, Las Vegas Valley, Nevada

In Las Vegas Valley, Nevada, the shallow alluvial aquifer zone is a possible source of contamination to the principal alluvial aquifers that provide 30% of the public drinking water supply for the valley. Development of the principal aquifers has lowered pressure head in the principal aquifers and created the potential for downward seepage from the shallow aquifer zone. This study was undertaken to characterize the hydrogeology and hydrogeochemistry of the shallow alluvial aquifer zone and to compare the hydrogeochemistry of the shallow and principal alluvial aquifer zones. A 37 well shallow ground water monitoring network was established and water-level, water-quality, and isotopic data were collected between June, 1988 and December, 1989. Water levels fluctuate seasonally and are influenced by land use practices. Irrigation influenced water levels are higher in fall and lower in winter while the natural water level pattern has lows in the fall and highs in the winter. Water temperature, pH, and EC appear to be unaffected by local land use practices. Temperatures are high in fall and low in spring. pH remains fairly constant near neutrality throughout the year. EC appears to be controlled by alternating variable length cycles of concentration and dilution of saline water near the water table. Water quality evolves along flow path from a fresh Ca2+-Mg2+-HCO3- type water with TDS around 300 mg/l in the north to a moderately saline Ca2+ - Mg2+-SO42- type water with TDS around 8000 mg/1 in the southeast near Las Vegas Wash. TDS varies temporally but does not follow a seasonal pattern. Ion ratios remain constant throughout the year. Water samples are generally oversaturated with respect to calcite, dolomite, and quartz, but are undersaturated with respect to gysum and amorphous silica. Delta D and o18 0 indicate that the water in the shallow aquifer zone originated as principal aquifer zone water. Comparison of shallow to principal aquifer zone data reveals that Ca2+, Mg2+, Cl-, SO42-, TDS, Si02, TOC, PO43-, B, Mn, Se, and tritium are all suitable for use as natural tracers for tracing the downward leakage of water from the shallow to the principal aquifer zone. Comparison of historical shallow aquifer zone data to the data generated during this investigation reveals that water levels in the shallow aquifer zone rose by an average of about 0.5 meter from 1972 to 1989 and that TDS increased by around 570 mg/1 between 1981 and 1989

High angular resolution mm- and submm-observations of dense molecular gas in M82

Researchers observed CO(7-6), CO(3-2), HCN(3-2) and HCO+(3-2) line emission toward the starburst nucleus of M82 and have obtained an upper limit to H13CN(3-2). These are the first observations of the CO(7-6), HCN(3-2) and HCO+(3-2) lines in any extragalactic source. Researchers took the CO(7-6) spectrum in January 1988 at the Infrared Telescope Facility (IRTF) with the Max Planck Institute for Extraterrestrial Physics/Univ. of California, Berkeley 800 GHz Heterodyne Receiver. In March 1989 researchers used the Institute for Radio Astronomy in the Millimeter range (IRAM) 30 m telescope to observe the CO(3-2) line with the new MPE 350 GHz Superconductor Insulator Superconductor (SIS) receiver and the HCN(3-2) and HCO+(3-2) lines with the (IRAM) 230 GHz SIS receiver (beam 12" FWHM, Blundell et al. 1988). The observational parameters are summarized

Open environments to support systems engineering tool integration: A study using the Portable Common Tool Environment (PCTE)

A study of computer engineering tool integration using the Portable Common Tool Environment (PCTE) Public Interface Standard is presented. Over a 10-week time frame, three existing software products were encapsulated to work in the Emeraude environment, an implementation of the PCTE version 1.5 standard. The software products used were a computer-aided software engineering (CASE) design tool, a software reuse tool, and a computer architecture design and analysis tool. The tool set was then demonstrated to work in a coordinated design process in the Emeraude environment. The project and the features of PCTE used are described, experience with the use of Emeraude environment over the project time frame is summarized, and several related areas for future research are summarized

Complete characterization of convergence to equilibrium for an inelastic Kac model

Pulvirenti and Toscani introduced an equation which extends the Kac caricature of a Maxwellian gas to inelastic particles. We show that the probability distribution, solution of the relative Cauchy problem, converges weakly to a probability distribution if and only if the symmetrized initial distribution belongs to the standard domain of attraction of a symmetric stable law, whose index $\alpha$ is determined by the so-called degree of inelasticity, $p>0$, of the particles: $\alpha=\frac{2}{1+p}$. This result is then used: (1) To state that the class of all stationary solutions coincides with that of all symmetric stable laws with index $\alpha$. (2) To determine the solution of a well-known stochastic functional equation in the absence of extra-conditions usually adopted

The Anatomy of the bill Tip of Kiwi and Associated Somatosensory Regions of the Brain: Comparisons with Shorebirds

Three families of probe-foraging birds, Scolopacidae (sandpipers and snipes), Apterygidae (kiwi), and Threskiornithidae (ibises, including spoonbills) have independently evolved long, narrow bills containing clusters of vibration-sensitive mechanoreceptors (Herbst corpuscles) within pits in the bill-tip. These ‘bill-tip organs’ allow birds to detect buried or submerged prey via substrate-borne vibrations and/or interstitial pressure gradients. Shorebirds, kiwi and ibises are only distantly related, with the phylogenetic divide between kiwi and the other two taxa being particularly deep. We compared the bill-tip structure and associated somatosensory regions in the brains of kiwi and shorebirds to understand the degree of convergence of these systems between the two taxa. For comparison, we also included data from other taxa including waterfowl (Anatidae) and parrots (Psittaculidae and Cacatuidae), non-apterygid ratites, and other probe-foraging and non probe-foraging birds including non-scolopacid shorebirds (Charadriidae, Haematopodidae, Recurvirostridae and Sternidae). We show that the bill-tip organ structure was broadly similar between the Apterygidae and Scolopacidae, however some inter-specific variation was found in the number, shape and orientation of sensory pits between the two groups. Kiwi, scolopacid shorebirds, waterfowl and parrots all shared hypertrophy or near-hypertrophy of the principal sensory trigeminal nucleus. Hypertrophy of the nucleus basorostralis, however, occurred only in waterfowl, kiwi, three of the scolopacid species examined and a species of oystercatcher (Charadriiformes: Haematopodidae). Hypertrophy of the principal sensory trigeminal nucleus in kiwi, Scolopacidae, and other tactile specialists appears to have co-evolved alongside bill-tip specializations, whereas hypertrophy of nucleus basorostralis may be influenced to a greater extent by other sensory inputs. We suggest that similarities between kiwi and scolopacid bill-tip organs and associated somatosensory brain regions are likely a result of similar ecological selective pressures, with inter-specific variations reflecting finer-scale niche differentiation

Probabilistic study of the speed of approach to equilibrium for an inelastic Kac model

This paper deals with a one--dimensional model for granular materials, which boils down to an inelastic version of the Kac kinetic equation, with inelasticity parameter $p>0$. In particular, the paper provides bounds for certain distances -- such as specific weighted $\chi$--distances and the Kolmogorov distance -- between the solution of that equation and the limit. It is assumed that the even part of the initial datum (which determines the asymptotic properties of the solution) belongs to the domain of normal attraction of a symmetric stable distribution with characteristic exponent \a=2/(1+p). With such initial data, it turns out that the limit exists and is just the aforementioned stable distribution. A necessary condition for the relaxation to equilibrium is also proved. Some bounds are obtained without introducing any extra--condition. Sharper bounds, of an exponential type, are exhibited in the presence of additional assumptions concerning either the behaviour, near to the origin, of the initial characteristic function, or the behaviour, at infinity, of the initial probability distribution function

Distributions of vascular plants in the Czech Republic. Part 8

The eighth part of the series on the distributions of vascular plants in the Czech Republic includes grid maps of 106 taxa in the genera Abutilon, Achillea. Arctium, Arenaria. Arnoseris, Carex. Chamaecytisus, Cornus, Diphasiastrum, Echinops. Galeopsis. Galium, Huperzia, Isoetes. Lyco-podiella. Lycopodium. Moehringia, Orobanche, Phelipanche, Prunus, Ranunculus, Selaginella. Stachys, Telekia, Typha and Zannichellia. These maps were produced by taxonomic experts based on examined herbarium specimens, literature and field records. Many of the studied native species are on the national Red List. They are represented by plants that are rare in the Czech Republic, in extreme cases confined to single sites (Arenaria grandiflora. Galium austriacum, Isoetes echinospora, I. lacustris and Orobanche teucrii). or that have experienced a considerable decline (e.g. Arnoseris minima. Carex hordeistichos, C. secalina. Diphasiastrum tristachyum and Lycopodiella inundata), or a combination of both (e.g. Orobanche artemisiae-campestris. O. coerulescens, Phelipanche arenaria. Ph. caesia and Stachys germanica). Three species (Moehringia muscosa, Selaginella helvetica and Typha minima) have been extirpated from this country. Alien species are represented by both archaeophytes (e.g. Arctium lappa, A. tomentosum, Orobanche minor, Stachys annua and S. arvensis) and neophytes (e.g. Abutilon theophrasti and Typha laxmannii). Two species have become invasive: Echinops sphaerocephalus spreads mainly in dry and disturbed habitats along roads and railways in warm lowlands, whereas Telekia speciosa is now locally frequent in various habitats mainly at middle and high elevations. Echinops bannaticus is reported here as a new alien species in the Czech Republic that occasionally escapes from cultivation. Spatial distributions and often also temporal dynamics of individual taxa are shown in maps and documented by records included in the Pladias database and available in electronic appendices. The maps are accompanied by comments that include additional information on the distribution, habitats, taxonomy and biology of the taxa

A multi-transition HCN and HCO+ study of 12 nearby active galaxies: AGN versus SB environments

Recent studies have indicated that the HCN-to-CO(J=1-0) and HCO+-to-HCN(J=1-0) ratios are significantly different between galaxies with AGN (active galactic nucleus) and SB (starburst) signatures. In order to study the molecular gas properties in active galaxies and search for differences between AGN and SB environments, we observed the HCN(J=1-0), (J=2-1), (J=3-2), HCO+(J=1-0) and HCO+(J=3-2), emission with the IRAM 30m in the centre of 12 nearby active galaxies which either exhibit nuclear SB and/or AGN signatures. Consistent with previous results, we find a significant difference of the HCN(J=2-1)-to-HCN(J=1-0), HCN(J=3-2)-to-HCN(J=1-0), HCO+(J=3-2)-to-HCO+(J=3-2), and HCO+-to-HCN intensity ratios between the sources dominated by an AGN and those with an additional or pure central SB: the HCN, HCO+ and HCO+-to-HCN intensity ratios tend to be higher in the galaxies of our sample with a central SB as opposed to the pure AGN cases which show rather low intensity ratios. Based on an LVG analysis of these data, i.e., assuming purely collisional excitation, the (average) molecular gas densities in the SB dominated sources of our sample seem to be systematically higher than in the AGN sources. The LVG analysis seems to further support systematically higher HCN and/or lower HCO+ abundances as well as similar or higher gas temperatures in AGN compared to the SB sources of our sample. Also, we find that the HCN-to-CO ratios decrease with increasing rotational number J for the AGN while they stay mostly constant for the SB sources.Comment: accepted for publication in ApJ; 20 pages, 7 figures; in emulateApJ forma