The identification of gamma ray induced EAS

Some of the penetrating particles in gamma-induced EAS from Cygnus X-3 observed by a single layer of flash-bulbs under 880 g cm/2 concrete, may be punched through photons rather than muons. An analysis of the shielded flash-tube response detected from EAS is presented. The penetration of the electro-magnetic component through 20 cm of Pb is observed at core distances approx. 10 m

Chemical Trends in the Ice Springs Basalt, Black Rock Desert, Utah

The Holocene Ice Springs volcanic field of west-central Utah consists of 0.53 km3 of tholeitic basalts erupted as a sequence of nested cinder cones and associated lava flows. Whole rock x-ray fluorescence and atomic absorption analysis of ninety-six samples of known relative age document statistically significant inter- and intra- eruption chemical variations. Elemental trends include increases in Ti, Fe, Ca, P, and Sr and decreases in Si, K, Rb, Ni, Cr, and Zr with decreasing age. Microprobe analyses of microphenocrysts of olivine, plagioclase, and Fe-Ti oxides and of groundmass olivine, plagioclase, and clinopyroxene indicate limited chemical variation between mineral assemblages of the eruptive events. Petrographic analyses have identified the presence of minor amounts of silicic xenoliths, orthopyroxene megacrysts, and plagioclase xenocrysts. Potassium-argon determinations establish the existence of excess argon in the basaltic cinder (30.05 x 10 -12 moles/gm) and in distal lava flows (8.29 x 10 -12 moles/gm) which suggest apparent ages of 16 and 4.3 million years respectively. Strontium isotopic data (Puskar and Condie, 1973) show systematic variations from oldest eruptions (87Sr/86Sr=0.7052) to youngest eruptions (87Sr/86Sr=0.7059). Theoretical evaluation of observed major element, trace element, isotopic, and thermophysical properties of the lavas and cinders limits the importance of proposed magmatic differentation processes. The data are compatible with model involving crystal fractionation, crustal assimilation, and magma mixing. Initial modification of mantle derived melts resulted from olivine fractionation at depth. Subsequent combination of 6 to 8% fractionation of plagioclase, minor olivine, and magnetite at shallow depths, less than one percent assimilation of silicic crustal basement rocks, and interaction of compositionally similar magma pulses explains the overall inter-eruption chemical trends. The intra-eruption variations follow the overall trends and a similar combination of processes of lesser magnitude accounts for the intra-eruption variations

Average features of the muon component of EAS or = 10(17) eV

Three 10 sq m liquid scintillators were situated at approximately 0 m, 150 m and 250 m from the center of the Haverah Park array. The detectors were shielded by lead/barytes giving muon detection thresholds of 317 MeV, 431 MeV and 488 MeV respectively. During part of the operational period the 431 MeV threshold was lowered to 313 MeV for comparison purposes. For risetime measurement fast phototubes were used and the 10% to 70% amplitude time interval was parameterized by T sub 70. A muon lateral density distribution of the form rho mu (R theta) = krho(500)0.94 1/R(1 + R/490)-eta has been fitted to the data for 120 m R 600 m and 0.27 (500) 2.55. The shower size parameter (500) is the water Cerenkov response at 500 m from the core of the extensive air showers (EAS) and is relatable to the primary energy. The results show general consistency

Muon fluctuation studies of EAS 10(17) eV

Fluctuation studies need to compare a parameter which is sensitive to longitudinal fluctuations against a parameter which is insensitive. Cascade calculations indicate that the shower size parameter at Haverah Park, rho (500), and the muon density are insensitive while parameters that significantly reflect the longitudinal development of a particular extensive air shower (EAS) include the muon/water Cerenkov response ratio and the muon arrival time dispersion. This paper presents conclusions based on muon fluctuation studies of EAS measured between 1976 and 1981 at Haverah Park

Endocrine disrupting effects on the nesting behaviour of male three-spined stickleback Gasterosteus aculeatus L

The analysis of patterns of temporal variability in the nesting behaviour of male threespined stickleback (Gasterosteus aculeatus) exposed to the synthetic oestrogen, 17β-ethinylestradiol, revealed immediate, but transient, treatment-related effects. Gluing frequency and time spent near nest were significantly reduced in exposed fish at the beginning of the experiment. The expression of these behaviours subsequently recovered and there was no effect of treatment on nest building success. The potential causes and implications of these findings are discussed

Radiometric dating and tuff mineralogy of omo group deposits

Journal ArticleThrough the efforts of the Omo Research Expedition and the East Rudolf Research Group, a large number of vertebrate fossils have been collected from the sedimentary deposits near the northern end of Lake Rudolf in Kenya and in the lower Omo valley in Ethiopia. The hominid fossils collected in this area have attracted the most attention, but the associated mammalian fossils are of equal importance, since they provide clues to the environment in which early man lived. Because these large collections of well-preserved material are extremely useful for correlation and for ascribing ages to other deposits, dating them is critical. In this chapter we try to describe some of the problems encountered in dating the deposits in the lower Omo valley, to assess some of the possible problems, and where possible to apply other controls to the radiometric dates. The work is not yet finished, and it may be many years before the final words are written on the age of these deposits. The following text is merely a summary of our knowledge to date

The muon content of EAS as a function of primary energy

The muon content of extensive air showers (EAS) was measured over the wide primary energy range 10 to the 16th power to 10 to the 20th power eV. It is reported that the relative muon content of EAS decreases smoothly over the energy range 10 to the 17th power to 10 to the 19th power eV and concluded that the primary cosmic ray flux has a constant mass composition over this range. It is also reported that an apparent significant change in the power index occurs below 10 to the 17th power eV rho sub c (250 m) sup 0.78. Such a change indicates a significant change in primary mass composition in this range. The earlier conclusions concerning EAS of energy 10 to the 17th power eV are confirmed. Analysis of data in the 10 to the 16th power - 10 to the 17th power eV range revealed a previously overlooked selection bias in the data set. The full analysis of the complete data set in the energy range 10 to the 16th power - 10 to the 17th power ev with the selection bias eliminated is presented

Fatalities due to intestinal obstruction following the ingestion of foreign bodies

Two fatalities due to an occlusive ileus following the ingestion of foreign bodies in patients with psychiatric disorders are described. A severely mentally handicapped young man developed a temperature and died 1 h after admission to a surgical ward. At autopsy, not, vert, similar 2000 cm3 of foreign material, including broken glass and porcelain, branches, buttons, parts of clothing and other material were found in the gastrointestinal tract, leading to a complete obstruction of the distal intestine and colon with resulting faecal vomiting. The other case was even more unusual as a hair fetishist had swallowed a thick strand of his own hair, 50 cm long, also resulting in mechanical obstruction of the distal intestine

Manifestations of quantum holonomy in interferometry

Abelian and non-Abelian geometric phases, known as quantum holonomies, have attracted considerable attention in the past. Here, we show that it is possible to associate nonequivalent holonomies to discrete sequences of subspaces in a Hilbert space. We consider two such holonomies that arise naturally in interferometer settings. For sequences approximating smooth paths in the base (Grassmann) manifold, these holonomies both approach the standard holonomy. In the one-dimensional case the two types of holonomies are Abelian and coincide with Pancharatnam's geometric phase factor. The theory is illustrated with a model example of projective measurements involving angular momentum coherent states.Comment: Some changes, journal reference adde

Singular forces and point-like colloids in lattice Boltzmann hydrodynamics

We present a second-order accurate method to include arbitrary distributions of force densities in the lattice Boltzmann formulation of hydrodynamics. Our method may be used to represent singular force densities arising either from momentum-conserving internal forces or from external forces which do not conserve momentum. We validate our method with several examples involving point forces and find excellent agreement with analytical results. A minimal model for dilute sedimenting particles is presented using the method which promises a substantial gain in computational efficiency.Comment: 22 pages, 9 figures. Submitted to Phys. Rev.