Clasts in the CM2 carbonaceous chondrite Lonewolf Nunataks 94101: evidence for aqueous alteration prior to complex mixing

Clasts in the CM2 carbonaceous chondrite Lonewolf Nunataks (LON) 94101 have been characterized using scanning and transmission electron microscopy and electron microprobe analysis to determine their degrees of aqueous alteration, and the timing of alteration relative to incorporation of clasts into the host. The provenance of the clasts, and the mechanism by which they were incorporated and mixed with their host material are also considered. Results show that at least five distinct types of clasts occur in LON 94101, of which four have been aqueously altered to various degrees and one is largely anhydrous. The fact that they have had different alteration histories implies that the main part of aqueous activity occurred prior to the mixing and assimilation of the clasts with their host. Further, the presence of such a variety of clasts suggests complex mixing in a dynamic environment involving material from various sources. Two of the clasts, one containing approximately 46 vol% carbonate and the other featuring crystals of pyrrhotite up to approximately 1 mm in size, are examples of unusual lithologies and indicate concentration of chemical elements in discrete areas of the parent body(ies), possibly by flow of aqueous solutions

Fine Grid Asteroseismology Of G117-B15A And R548

We now have a good measurement of the cooling rate of G117-B15A. In the near future, we will have equally well determined cooling rates for other pulsating white dwarfs, including R548. The ability to measure their cooling rates offers us a unique way to study weakly interacting particles that would contribute to their cooling. Working toward that goal, we perform a careful asteroseismological analysis of G117-B15A and R548. We study them side by side because they have similar observed properties. We carry out a systematic, fine grid search for best-fit models to the observed period spectra of those stars. We freely vary four parameters: the effective temperature, the stellar mass, the helium layer mass, and the hydrogen layer mass. We identify and quantify a number of uncertainties associated with our models. Based on the results of that analysis and fits to the periods observed in R548 and G117-B15A, we clearly define the regions of the four-dimensional parameter space occupied by the best-fit models.NSF AST 05-07639Astronom

A New Timescale for Period Change in the Pulsating DA White Dwarf WD 0111+0018

We report the most rapid rate of period change measured to date for a pulsating DA (hydrogen atmosphere) white dwarf (WD), observed in the 292.9 s mode of WD 0111+0018. The observed period change, faster than 10^{-12} s/s, exceeds by more than two orders of magnitude the expected rate from cooling alone for this class of slow and simply evolving pulsating WDs. This result indicates the presence of an additional timescale for period evolution in these pulsating objects. We also measure the rates of period change of nonlinear combination frequencies and show that they share the evolutionary characteristics of their parent modes, confirming that these combination frequencies are not independent modes but rather artifacts of some nonlinear distortion in the outer layers of the star.Comment: 10 pages, 6 figures, accepted for publication in The Astrophysical Journa

Sudbury project (University of Muenster-Ontario Geological Survey): Field studies 1984-1989 - summary of results

In cooperation between the Ontario Geological Survey and the Institute of Geology and Institute of Planetology, geological, petrological, and geochemical studies were carried out on impact-related phenomena of the Sudbury structure during the last decade. The main results of the field studies are briefly reviewed. Footwall rocks, sublayer, and lower sections of the Sudbury Igneous Complex (SIC) were mainly mapped and sampled in the northern (Levack Township) and western (Trillabelle and Sultana Properties) parts of the north range. Within these mapping areas Sudbury Breccias (SB) and Footwall Breccias (FB) were studied; SB were also investigated along extended profiles beyond the north and south ranges up to 55 km from the SIC. The Onaping Formation (OF) and the upper section of the SIC were studied both in the north range (Morgan and Dowling Townships) and in the southern east range (Capreol and McLennan Townships)

Analysing trade-offs in container loading: Combining load plan construction heuristics with agent-based simulation

This is the accepted version of the following article: Analysing Trade-offs in Container Loading: Combining Load Plan Construction Heuristics with Agent-based Simulation. International Transactions in Operational Research, 20(4): 471-491which has been published in final form at http://onlinelibrary.wiley.com/doi/10.1111/itor.12017/abstractIn this paper we describe two operations research techniques, cutting and packing optimisation (CPO) and simulation, and present a multi-methodology approach for analysing the trade-offs between loading efficiency and various important practical considerations in relation to the cargo, such as its stability, fragility or possible cross-contamination between different types of items over time. The feasibility of this approach is demonstrated by considering a situation where the items to be loaded have differing degrees of perishability and where badly deteriorated items can affect those in their immediate vicinity (e.g. through the spread of mould). Our approach uses the output of the CPO algorithms to create agents that simulate the spread of mould through proximity-based interactions between the agents. The results show the trade-offs involved in container utilisation and the propagation of mould, without evidence of any correlation between them. The contribution of this research is the methodology and the feasibility study

First Season QUIET Observations: Measurements of Cosmic Microwave Background Polarization Power Spectra at 43 GHz in the Multipole Range 25 ≤ ℓ ≤ 475

The Q/U Imaging ExperimenT (QUIET) employs coherent receivers at 43 GHz and 94 GHz, operating on the Chajnantor plateau in the Atacama Desert in Chile, to measure the anisotropy in the polarization of the cosmic microwave background (CMB). QUIET primarily targets the B modes from primordial gravitational waves. The combination of these frequencies gives sensitivity to foreground contributions from diffuse Galactic synchrotron radiation. Between 2008 October and 2010 December, over 10,000 hr of data were collected, first with the 19 element 43 GHz array (3458 hr) and then with the 90 element 94 GHz array. Each array observes the same four fields, selected for low foregrounds, together covering ≈1000 deg^2. This paper reports initial results from the 43 GHz receiver, which has an array sensitivity to CMB fluctuations of 69 μK√s. The data were extensively studied with a large suite of null tests before the power spectra, determined with two independent pipelines, were examined. Analysis choices, including data selection, were modified until the null tests passed. Cross-correlating maps with different telescope pointings is used to eliminate a bias. This paper reports the EE, BB, and EB power spectra in the multipole range ℓ = 25-475. With the exception of the lowest multipole bin for one of the fields, where a polarized foreground, consistent with Galactic synchrotron radiation, is detected with 3σ significance, the E-mode spectrum is consistent with the ΛCDM model, confirming the only previous detection of the first acoustic peak. The B-mode spectrum is consistent with zero, leading to a measurement of the tensor-to-scalar ratio of r = 0.35^(+1.06)_(–0.87). The combination of a new time-stream "double-demodulation" technique, side-fed Dragonian optics, natural sky rotation, and frequent boresight rotation leads to the lowest level of systematic contamination in the B-mode power so far reported, below the level of r = 0.1

Runoff properties of extreme discharges on Parana and Uruguay rivers

Climate variability in different spatial scales is a study area which has reached interest in application, especially during de last years. River discharges can be considered as a robust integrator of the properties of the basin; under these premises the goal of this work is to analyse flows from the Parana and Uruguay rivers in several gauge stations ´ and study the behavior of positive and negative anomalies and their extremes. The variable to be analysed was defined as the number of anomalies with the same sign per year. Results show that the structures are different for both rivers, which implies a different stochastic process. Identical representativeness was found between the anomaly series in each river. The risk estimation of extremes in both rivers indicates that it is possible to establish a decision model. Additionally, the series of annual number of anomalies presented a climatic jump in the seventies, for both rivers.Fil: Vargas, Walter Mario. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ciencias de la Atmósfera y los Océanos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Bischoff, S.. Ministerio de Defensa. Secretaria de Planeamiento. Servicio Meteorológico Nacional; ArgentinaFil: Naumann, Gustavo. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ciencias de la Atmósfera y los Océanos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Marcuzzi, E.. Plan Nacional de Manejo del Fuego; Argentin

Boundary non-crossings of Brownian pillow

Let B_0(s,t) be a Brownian pillow with continuous sample paths, and let h,u:[0,1]^2\to R be two measurable functions. In this paper we derive upper and lower bounds for the boundary non-crossing probability \psi(u;h):=P{B_0(s,t)+h(s,t) \le u(s,t), \forall s,t\in [0,1]}. Further we investigate the asymptotic behaviour of $\psi(u;\gamma h)$ with $\gamma$ tending to infinity, and solve a related minimisation problem.Comment: 14 page