Continuous monitoring of the lunar or Martian subsurface using on-board pattern recognition and neural processing of Rover geophysical data

The ultimate goal is to create an extraterrestrial unmanned system for subsurface mapping and exploration. Neural networks are to be used to recognize anomalies in the profiles that correspond to potentially exploitable subsurface features. The ground penetrating radar (GPR) techniques are likewise identical. Hence, the preliminary research focus on GPR systems will be directly applicable to seismic systems once such systems can be designed for continuous operation. The original GPR profile may be very complex due to electrical behavior of the background, targets, and antennas, much as the seismic record is made complex by multiple reflections, ghosting, and ringing. Because the format of the GPR data is similar to the format of seismic data, seismic processing software may be applied to GPR data to help enhance the data. A neural network may then be trained to more accurately identify anomalies from the processed record than from the original record

Turnover of microbial biomass, plant residues and soil humic constituents under field conditions

Includes bibliographical references (pages 156-157).The effects of soil texture and climatic conditions on turnover rates of plant residues were measured under field conditions. Carbon-14- and 15N-labelled straw made it possible to follow degradation rates of the original substrate and of the soil organic constituents formed during the initial degradation process. Subsequent sampling measured the turnover of the active fraction. Carbon dating was used to measure the turnover rates of the more resistant fraction. Fractionation of the soil during the first two years showed greater accumulation of a condensed aromatic moiety (humic acid A) in the medium-textured Luvisolic soil and in the coarse-textured Dark Brown Chernozemic (Kastanozem). High clay grassland soils showed protection of aliphatic nitrogen from further humification. Much of the initial nitrogen and carbon mineralization of soil organic materials produced on decomposition of the straw came from the fulvic acids which contained a predominance of recently synthesized low molecular weight materials. Carbon and nitrogen incorporation into the > 0.2 μm fraction lagged behind incorporation into other fractions. Large quantities of immobilized carbon and nitrogen were contained in the > 0.2 μm fraction as well as in the 0.04 μm sedimentation fraction allowing these two fractions to act as sources of slowly released nitrogen. Residual humic acid carbon and nitrogen turnover was best estimated from carbon dating of the carbon after fractionation of the soil. The nitrogen turnover was calculated utilizing the C/N ratios of the fractions. Acid hydrolysis was found to be the simplest method of fractionation of large quantities of soil for carbon dating and for specific components. Na4P2O7 extraction followed by peptization and sediment analysis proved useful for measuring C and N transformations on a shorter term basis

Fractionation of soil and 15N nitrogen to separate the organic and clay interactions of immobilized N

Includes bibliographical references (pages 211-212).Labelled 15N was added to two soils in cylinders in the field, and allowed to equilibrate for two summers of crop growth. The labelled soils were fractionated to provide information on the effect of organic and inorganic colloids on the stabilization of immobilized, 15N. Organic materials removed by 0.5 N NaOH without pretreatment contained more 15N than those extracted by the same reagent following decalcification and removal of sesquioxides with dithionite and HCl. Both extracts had similar amino acid (contents) and similar degrees of hydrolability. A fractionation system using an initial 0.1 M NaOH–0.1 M Na4P2O7 extraction followed by sonication and peptization in H2O yielded a humic acid fraction and a sedimentation fraction (< 0.04 μm) which differed markedly in degree of hydrolyzability, 15N content and amino acid-N content. The N associated with inorganic colloids < 0.04 μm, and that remaining in solution after the removal of larger particles accounted for 50% of the amino acid-N in a clay soil, and 40% in a fine sandy loam soil. Removal of sesquioxides followed by a second 0.5 N NaOH extraction reduced the N content of the colloidal size fractions of both soils, indicating that amorphous iron and aluminum compounds on the surface of clays are probably the active agents in bonding organic N to inorganic colloids. It is suggested that the nonhydrolytic technique, based largely on dispersion of the inorganic–organic colloids and analyses of the sediment, could be used to interpret the fate of microbiologically immobilized N compounds in the soil. Materials removed by 0.1 M Na4P2O7 were associated with polyvalent cations in the soil. Materials such as cytoplasmic constituents, released from the biomass during ultrasonic vibration or as lytic products would be expected to be adsorbed to inorganic colloids. They should be concentrated in the < 0.04 μm-size fraction. Cell wall and other particulate debris with a faster setting velocity would be expected to appear in larger-sized sedimentation fractions

Electron tunneling time measured by photoluminescence excitation correlation spectroscopy

The tunneling time for electrons to escape from the lowest quasibound state in the quantum wells of GaAs/AlAs/GaAs/AlAs/GaAs double-barrier heterostructures with barriers between 16 and 62 Å has been measured at 80 K using photoluminescence excitation correlation spectroscopy. The decay time for samples with barrier thicknesses from 16 Å (≈12 ps) to 34 Å(≈800 ps) depends exponentially on barrier thickness, in good agreement with calculations of electron tunneling time derived from the energy width of the resonance. Electron and heavy hole carrier densities are observed to decay at the same rate, indicating a coupling between the two decay processes

Radial Redshift Space Distortions

The radial component of the peculiar velocities of galaxies cause displacements in their positions in redshift space. We study the effect of the peculiar velocities on the linear redshift space two point correlation function. Our analysis takes into account the radial nature of the redshift space distortions and it highlights the limitations of the plane parallel approximation. We consider the problem of determining the value of \beta and the real space two point correlation function from the linear redshift space two point correlation function. The inversion method proposed here takes into account the radial nature of the redshift space distortions and can be applied to magnitude limited redshift surveys that have only partial sky coverage.Comment: 26 pages including 11 figures, to appear in Ap

Statistical Arbitrage Mining for Display Advertising

We study and formulate arbitrage in display advertising. Real-Time Bidding (RTB) mimics stock spot exchanges and utilises computers to algorithmically buy display ads per impression via a real-time auction. Despite the new automation, the ad markets are still informationally inefficient due to the heavily fragmented marketplaces. Two display impressions with similar or identical effectiveness (e.g., measured by conversion or click-through rates for a targeted audience) may sell for quite different prices at different market segments or pricing schemes. In this paper, we propose a novel data mining paradigm called Statistical Arbitrage Mining (SAM) focusing on mining and exploiting price discrepancies between two pricing schemes. In essence, our SAMer is a meta-bidder that hedges advertisers' risk between CPA (cost per action)-based campaigns and CPM (cost per mille impressions)-based ad inventories; it statistically assesses the potential profit and cost for an incoming CPM bid request against a portfolio of CPA campaigns based on the estimated conversion rate, bid landscape and other statistics learned from historical data. In SAM, (i) functional optimisation is utilised to seek for optimal bidding to maximise the expected arbitrage net profit, and (ii) a portfolio-based risk management solution is leveraged to reallocate bid volume and budget across the set of campaigns to make a risk and return trade-off. We propose to jointly optimise both components in an EM fashion with high efficiency to help the meta-bidder successfully catch the transient statistical arbitrage opportunities in RTB. Both the offline experiments on a real-world large-scale dataset and online A/B tests on a commercial platform demonstrate the effectiveness of our proposed solution in exploiting arbitrage in various model settings and market environments.Comment: In the proceedings of the 21st ACM SIGKDD international conference on Knowledge discovery and data mining (KDD 2015

Charge order, dynamics, and magneto-structural transition in multiferroic LuFe2_2O4_4

We investigated the series of temperature and field-driven transitions in LuFe$_2$O$_4$ by optical and M\"{o}ssbauer spectroscopies, magnetization, and x-ray scattering in order to understand the interplay between charge, structure, and magnetism in this multiferroic material. We demonstrate that charge fluctuation has an onset well below the charge ordering transition, supporting the "order by fluctuation" mechanism for the development of charge order superstructure. Bragg splitting and large magneto optical contrast suggest a low temperature monoclinic distortion that can be driven by both temperature and magnetic field.Comment: 4 pages, 3 figures, PRL in prin

The Correlation Function in Redshift Space: General Formula with Wide-angle Effects and Cosmological Distortions

A general formula for the correlation function in redshift space is derived in linear theory. The formula simultaneously includes wide-angle effects and cosmological distortions. The formula is applicable to any pair with arbitrary angle $\theta$ between lines of sight, and arbitrary redshifts, $z_1$, $z_2$, which are not necessarily small. The effects of the spatial curvature both on geometry and on fluctuation spectrum are properly taken into account, and thus our formula holds in a Friedman-Lema\^{\i}tre universe with arbitrary cosmological parameters $\Omega_0$ and $\lambda_0$. We illustrate the pattern of the resulting correlation function with several models, and also show that validity region of the conventional distant observer approximation is $\theta \le 10^\circ$.Comment: 45 pages including 9 figures, To Appear in Astrophys. J. 535 (2000

Psychological climates in action learning sets: A manager’s perspective

Action Learning (AL) is often viewed as a process that facilitates professional learning through the creation of a positive psychological climate (Marquart, 2000; Schein, 1979). An psychological climate that fosters an environment in which learning set members feel psychologically safe enough to reflect upon both the successes, and failures in their professional life without any form of repercussion. However, there has been little attention given to the ways that that psychological climate develops, and the differing facets that create that climate. In response to such deficit, this paper reports the outcomes of interviews with eleven managers, all of whom are former AL set members on their experiences of action learning set membership. Drawing upon an interpretivist philosophy, the paper explores the key themes that emerged from the analysis of those interviews. The analysis serves to illustrate the differing facets that collectively contribute creation of a positive psychological climate that is conducive for learning. Analysis points to the relative importance of such facets as: trust, honesty, vulnerability, reciprocity, confidentiality and personal disclosure, all of which have the capacity to lead to a positive psychological climate in action learning sets. This paper is useful for developing an understanding of the differing facets in AL sets that create a psychological climate conducive for learning. As such, it has utility for action learning facilitators, set members, academics and educational consultants

Increased proportion of active soil N in Breton loam under cropping systems with forages and green manures

Total soil N and N mineralization rate partially ctririct&iie the influence olvariouJcropping systems on the growth of.sequent.crop.s in a rotation' The objectives of this study were to (1) quantify the relationship among cropping system, total N and mineralizable N, and (2) compare amount of N mineralized under'controlled laboratory conditions-with pianl N uptake under green]ouse conditi:ns. Three cropping systems that have been in operation between 9 and 60 yr on a Gray-Luvisol (Breton loam; were ^selected . They included: (1) an ag.lo: ecological (lnn) d-yr rotation involving fabibeans as gr-een manure (AER1 sampled after the_first lababean crop-?nq AER? ,u-pied after 3 yr of continuous forage)l (2) continuous grain system (CG), with fertilizer N at 90 kg ha-'^yr- '; inttrated in 1980 and considered established in f"98i; i3) a classicial Ereton iotation (CBR) involving 9]o-ng-term (ca. 1930) 5-yr rotation with forages and cereals and no return of.ciop residues (CBR1 fertilized with P-K-S and CBR2 unfertilized). We cautio_n that not all ohlses of each rotation were sampled: bur conclusions pertain to N-mineralization potential in soil samples immediately preceding barley as sequent crop in each rotation. The rate ofN mineralization declined with time, but it remained greater than iero aftei 20 wi AER2 > > CBRI > CBR2 : CG. Mineralizable soil N, following one cycle of the AER rotation, was almost double that following 60 yr of the CBR rotation. Data for mineral-N accumulation under laboratory conditions were described best by a single-component expo-n-ential model. Legume-based rotations were associated with increased total soil N and a greater proportional increase in active N than in total soilN. Active N was least in soil under the CG system. The incubation-extraction procedure resulted in higher estimates of mineralizable N than did the plant-uptake method; liowever, the ranking of N-supplying power of soils was the same