Geoelectrical Possibilities of Detecting Stream Channels in Carbonate Rocks

Several geoelectrical resistivity methods that may be used to determine the position and flow characteristics of underground water associated with carbonate bedrock and karst development are considered. The most promising method studied employs depth soundings patterned after Schlumberger. The plotting of half electrode separation against apparent resistivity yields a curve which may be used to discriminate between lateral and vertical inhomogeneities in bedrock. A network of depth soundings of this type ultimately may lead to a map that will show geoelectrical anisotropies that may be used to analyze subsurface water courses in carbonate rock

Fermionization, Convergent Perturbation Theory, and Correlations in the Yang-Mills Quantum Field Theory in Four Dimensions

We show that the Yang-Mills quantum field theory with momentum and spacetime cutoffs in four Euclidean dimensions is equivalent, term by term in an appropriately resummed perturbation theory, to a Fermionic theory with nonlocal interaction terms. When a further momentum cutoff is imposed, this Fermionic theory has a convergent perturbation expansion. To zeroth order in this perturbation expansion, the correlation function $E(x,y)$ of generic components of pairs of connections is given by an explicit, finite-dimensional integral formula, which we conjecture will behave as $$E(x,y) \sim |x - y|^{-2 - 2 d_G},$$ \noindent for $|x-y|>>0,$ where $d_G$ is a positive integer depending on the gauge group $G.$ In the case where $G=SU(n),$ we conjecture that $$d_G = {\rm dim}SU(n) - {\rm dim}S(U(n-1) \times U(1)),$$ \noindent so that the rate of decay of correlations increases as $n \to \infty.$Comment: Minor corrections of notation, style and arithmetic errors; correction of minor gap in the proof of Proposition 1.4 (the statement of the Proposition was correct); further remark and references adde

Methods of determining aquifer storage capacity and fresh-saline water interfaces by geoelectrical investigations

Students supported: One graduate student supportedGeoelectrical investigations in Grundy County of northwestern Missouri where the groundwater resources of the glacial deposits have already been examined through an extensive drilling program by the Missouri Geological Survey and Water Resources, indicate that water-bearing gravel deposits can be distinguished from glacial deposits containing appreciable amounts of clay and limited, amounts of water. The Schlumberger method used for the geoelectric depth soundings in the vicinity of the Survey's drillholes demonstrates the exploratory usefulness of the method in that it can partly replace the more expensive procedure of drilling. The method also provides improved interpretation between drillholes. Results of the investigation show that, in the area, clay has a resistivity below 20(omega)m, that the fresh water-bearing gravel at the bottom of the buried glacial stream channels has a resisitivity of 40 to 50 (omega)m, and that the near surface glacial gravel deposits have a resistivity above 100 (omega)m. Interpretation of the depth soundings and the conductivity of water obtained from a local well implies that its water is drawn from the saline water of the bedrock. A recommendation is made for the quality improvement of this particular well.Project # A-046-MO Agreement # 14-31-0001-352

STRATA-VARIOUS: A flexible Fortran program for dynamic forward modeling of stratigraphy

STRATA-VARIOUS version 1.3 is a computer program written in Fortran 77 to perform two-dimensional forward modeling of stratigraphic processes. We designed specific features of the program to investigate orbital forcing of high-frequency glacioeustasy. This requires forward modeling of many hundreds of sea-level stillstands and the graphic display of relatively precise spatial details. To use this program, the user constructs files that specify the times and elevations of sea-level stillstands, the initial basement topography, numerous parameters that control the geometry and physical properties of stratigraphic beds, the isostatic response of the lithosphere, the pattern of tectonic subsidence and uplift, the number and scale of desired output cross sections, etc. Two features of this program are especially novel. Whereas many forward-modeling programs store information about stratigraphic beds in fixed-size horizontal bins, our program retains in memory the precise locations of all horizontal locations where any stratigraphic bed undergoes any distinct change. This allows us to obtain regional cross sections and magnified sections that preserve information about the geometry and lithology of individual beds. Second, for clastic sediments we have developed a realistic parametric scheme for describing how sea-level variation affects the sediment discharge rate. The parameters that control this scheme have simple physical interpretations in terms of the dimensions, erosion rates, etc. for the alluvial valley responsible for the sediment supply. In this article we give various examples of STRATA-VARIOUS graphic output to illustrate model sensitivity and to demonstrate some of the options available

Degradation of LaMnO{3-y} surface layer in LaMnO{3-y}/ metal interface

We report electrical measurements showing the degradation processes of LaMnO$_{3-y}$ (LaMnO) in LaMnO/normal metal interface in both point contact and planar-type junctions. Immediately after the preparation of the interface, the degradation process was followed by measuring the evolution of the junction resistance versus time. This process is characterized by the appearance of a second maximum in the resistance vs. temperature (R-T) dependence at temperatures lower than the Curie temperature T$_c$, at which the metal-insulator transition occurs in the bulk. These effects are explained in terms of the formation of a depleted interface layer in LaMnO caused by an out-diffusion of oxygen from the manganite surface to the normal metal. This assumption is confirmed by XPS measurement. Similar results on LaSrMnO$_{3-y}$ interfaces are also obtained.Comment: 4 pages, 3 figures, accepted for publication in Appl. Phys. Lett.(2002

The detection of subsurface stream channels in carbonate rocks by geoelectrical methods

Student supported: 1 Student AssistantThe distinction of partially dissolved from compact carbonate rocks and from the alluvial overburden is a major problem in geological engineering and water resources. Geoelectrical depth soundings after Schlumberger were applied over karst terraines in three locations of the Ozarks in Missouri. The zone of dissolved carbonate rock shows intermediate resistivities between low values for the overburden and extremely high values for the compact rock. The main part of the investigation was directed towards solving the underground flow and disappearance of Logan Creek near Ellington, Missouri. Combined geoelectrical and gravity surveys under consideration of some near surface seismic refractions indicate zones of increased depth and degree of dissolution at the Ellington Fault. A detailed gravity profile across the fault shows a negative anomaly with a minimum of -2.0 mgal, which extends over approximately 3 miles with large lateral gradients. A theoretical model can explain the anomaly if the depth of the cavernous limestone has a maximum of 350 feet and if the bulk volume of fissures and stream channels amounts to 15 percent. The coincidence between the fault and the negative anomaly suggests that ruptures along fault planes weakened the rock so that chemical dissolution from surface waters had a greater penetration.Project # A-065-MO Agreement # 14-31-0001-382

Family memories in the home: contrasting physical and digital mementos

We carried out fieldwork to characterise and compare physical and digital mementos in the home. Physical mementos are highly valued, heterogeneous and support different types of recollection. Contrary to expectations, we found physical mementos are not purely representational, and can involve appropriating common objects and more idiosyncratic forms. In contrast, digital mementos were initially perceived as less valuable, although participants later reconsidered this. Digital mementos were somewhat limited in function and expression, largely involving representational photos and videos, and infrequently accessed. We explain these digital limitations and conclude with design guidelines for digital mementos, including better techniques for accessing and integrating these into everyday life, allowing them to acquire the symbolic associations and lasting value that characterise their physical counterparts

Composition of the Innermost Core Collapse Supernova Ejecta

With presently known input physics and computer simulations in 1D, a self-consistent treatment of core collapse supernovae does not yet lead to successful explosions, while 2D models show some promise. Thus, there are strong indications that the delayed neutrino mechanism works combined with a multi-D convection treatment for unstable layers. On the other hand there is a need to provide correct nucleosynthesis abundances for the progressing field of galactic evolution and observations of low metallicity stars. The innermost ejecta is directly affected by the explosion mechanism, i.e. most strongly the yields of Fe-group nuclei for which an induced piston or thermal bomb treatment will not provide the correct yields because the effect of neutrino interactions is not included. We apply parameterized variations to the neutrino scattering cross sections and alternatively, parameterized variations are applied to the neutrino absorption cross sections on nucleons in the ``gain region''. We find that both measures lead to similar results, causing explosions and a Ye>0.5 in the innermost ejected layers, due to the combined effect of a short weak interaction time scale and a negligible electron degeneracy, unveiling the proton-neutron mass difference. We include all weak interactions (electron and positron capture, beta-decay, neutrino and antineutrino capture on nuclei, and neutrino and antineutrino capture on nucleons) and present first nucleosynthesis results for these innermost ejected layers to discuss how they improve predictions for Fe-group nuclei. The proton-rich environment results in enhanced abundances of 45Sc, 49Ti, and 64Zn as requested by chemical evolution studies and observations of low metallicity stars as well as appreciable production of nuclei in the mass range up to A=80.Comment: 13 pages, 8 figures. Final versio

Socioeconomic inequalities in secondhand smoke exposure before, during and after implementation of Quebec's 2015 'An Act to Bolster Tobacco Control'

BACKGROUND: To better understand whether tobacco control policies are associated with changes in secondhand smoke (SHS) exposure across socioeconomic groups, we monitored differences in socioeconomic inequalities in SHS exposure in households and private vehicles among youth and adults before, during and after adoption of Quebec’s 2015 An Act to Bolster Tobacco Control. METHODS: Using data from the Canadian Community Health Survey, we examined the prevalence of daily exposure to SHS in households and private vehicles among youth (ages 12 to 17) and adults (ages 18+) across levels of household education and income (separately) in 2013/2014, 2015/2016 and 2017/2018. We tested differences in the magnitude of differences in outcomes over time across education and income categories using logistic models with interaction terms, controlling for age and sex. RESULTS: We detected inequalities in SHS exposure outcomes at each time point, most markedly at home among youth (OR of SHS exposure among youth living in the 20% poorest households vs the 20% richest=4.9, 95% CI 2.7 to 6.2). There were decreases in SHS exposure in homes and cars in each education/income group over time. The magnitude of inequalities in SHS exposure in homes and cars, however, did not change during this period. CONCLUSIONS: The persistence of socioeconomic inequalities in SHS exposure despite implementation of new tobacco control laws represents an increasingly worrisome public health challenge, particularly among youth. Policymakers should prioritise the reduction of socioeconomic inequalities in SHS exposure and consider the specific needs of socioeconomically disadvantaged populations in the design of future legislation