Evaluation of a Mechanical System for Reconstructing Soil on Surface Mined Land

The existence of excessive soil compaction has hindered the surface mining industry from returning land to pre−mining productivity after reclamation, especially on prime farmland soils. Heavy earthmoving equipment used during reclamation tends to generate root−limiting bulk densities that adversely affect plant growth thereby decreasing yields. Therefore, the purpose of this study was to evaluate a mechanism, called the ‘Soil Regenerator,’ which reconstructs soil media at minimum bulk density during surface mine reclamation. The prototype soil forming mechanism was mounted on the front of a conventional bulldozer. Soil was placed in long narrow windrows by a scraper or bulldozer. As the bulldozer pushed into the windrow, soil rose up the blade and was agitated, transported, and deposited by a helicoid auger in a 0.9−m deep berm adjacent to the bulldozer. The capacity of the prototype ranged from 490 to 804 m3/h while producing bulk densities ≤ 1.0 Mg/m3 and penetrometer measurements below 0.7 MPa. These measurements demonstrated the capability of the ‘Soil Regenerator’ to eliminate soil compaction on reclaimed surface mined land and to reconstruct soil more suitable for crop growth

Integral Grothendieck-Riemann-Roch theorem

We show that, in characteristic zero, the obvious integral version of the Grothendieck-Riemann-Roch formula obtained by clearing the denominators of the Todd and Chern characters is true (without having to divide the Chow groups by their torsion subgroups). The proof introduces an alternative to Grothendieck's strategy: we use resolution of singularities and the weak factorization theorem for birational maps.Comment: 24 page

On the number of representations providing noiseless subsystems

This paper studies the combinatoric structure of the set of all representations, up to equivalence, of a finite-dimensional semisimple Lie algebra. This has intrinsic interest as a previously unsolved problem in representation theory, and also has applications to the understanding of quantum decoherence. We prove that for Hilbert spaces of sufficiently high dimension, decoherence-free subspaces exist for almost all representations of the error algebra. For decoherence-free subsystems, we plot the function $f_d(n)$ which is the fraction of all $d$-dimensional quantum systems which preserve $n$ bits of information through DF subsystems, and note that this function fits an inverse beta distribution. The mathematical tools which arise include techniques from classical number theory.Comment: 17 pp, 4 figs, accepted for Physical Review

995-22 The Effect of Perioperative Storage Solutions on the Long Term Vein Graft Function and Morphology

It has been shown that suboptimal preparation of a vein graft prior to its insertion results in immediate morphological and functional damage to the endothelial cells but not to the underlying smooth muscle cells. However. little is known if such perioperative injury to the vein grafts may influence the subsequent development of intimal hyperplasia and smooth muscle cell contractility. This study examines the influence of storage in saline or Ringer's lactate on the development of intimal hyperplasia and vasomotor function in experimental vein grafts. Twenty-six NM rabbits had a carotid vein bypass graft performed after the veins had been immersed (15 minutes) in either heparinized saline (Sal; n=13) or Ringer's lactate (RL; n=13) and each group was harvested after 28 days for either histology (n=8) or functional studies (n=5; four 5 mm rings/graft). Saline storage of the vein graft resulted in a 38% increase in the thickness of the intimal hyperplasia (113±2 vs. 83±μm, Sal vs. RL; mean±SEM, p<0.05) without a change in medial thickness (87±5 vs. 86±8μm, Sal vs. RL; p>0.05). There was no difference in the sensitivity to norepinephrine, serotonin and bradykinin between the two sets of vein grafts. The maximal contractile forces to serotonin and bradykinin were increased in the saline compared to Ringer's lactate stored vein grafts.SalineRinger'sp-valueNorepinephrine0.88±0.121.57±020<0.05Serotonin1.23±0.150.37±013<0.01Bradykinin2.08±0.110.52±007<0.01Values are the standardized maximal contractile force (maximal contraction/contraction to 60 mM KCI) expressed as mean±SEM.Saline storage of the vein graft results in the increased development of intimal hyperplasia with an overall enhanced contractility but without changes in agonist sensitivity. This study places further emphasis on the need for good perioperative care of the vein bypass graft because it results not only in the previously documented short term problems but also in long term structural and contractile changes which may contribute to decreased graft patency

High Temperature Conductance of the Single Electron Transistor

The linear conductance of the single electron transistor is determined in the high temperature limit. Electron tunneling is treated nonperturbatively by means of a path integral formulation and the conductance is obtained from Kubo's formula. The theoretical predictions are valid for arbitrary conductance and found to explain recent experimental data.Comment: 4 pages, 2 figure

Calibration of <i>Herschel</i> SPIRE FTS observations at different spectral resolutions

The SPIRE Fourier Transform Spectrometer on-board the Herschel Space Observatory had two standard spectral resolution modes for science observations: high resolution (HR) and low resolution (LR), which could also be performed in sequence (H+LR). A comparison of the HR and LR resolution spectra taken in this sequential mode revealed a systematic discrepancy in the continuum level. Analysing the data at different stages during standard pipeline processing demonstrates that the telescope and instrument emission affect HR and H+LR observations in a systematically different way. The origin of this difference is found to lie in the variation of both the telescope and instrument response functions, while it is triggered by fast variation of the instrument temperatures. As it is not possible to trace the evolution of the response functions using housekeeping data from the instrument subsystems, the calibration cannot be corrected analytically. Therefore, an empirical correction for LR spectra has been developed, which removes the systematic noise introduced by the variation of the response functions

Reversing microcrystalline tests: an analytical approach to recycling of microcrystals from drugs of abuse

A combined analysis of microcrystalline tests followed by LC-MS or GC-MS analysis is described. Microcrystalline tests are shown to be non-destructive as addition products formed were easily dissociated after the application of an appropriate solvent. Subsequent analysis of the sample was done to quantify the recovery of the drug. Examples were performed using the date rape drug γ-hydroxybutyrate (GHB) and the synthetic opioid methadone

Analysis of the mutual inductance between two parallel plates for the detection of surface flaws

There has recently been much effort behind the development of NDE methods applicable to the detection of surface/subsurface flaws in thin metallic structures with a rapid scan capability. One such method, an electromagnetic technique using a current-sheet parallel to the surface of a specimen in order to induce eddy current flow shows a high potential for satisfying the rapid scan requirement stated above. The technique is based on the detection of flaw-induced magnetic field components normal to the specimen surface by an appropriate detection mechanism positioned above the current-sheet as shown schematically in Fig. 1. As indicated in this figure, the current-sheet separates the source of the normal magnetic field components from the detector in such a way that the electric and magnetic properties of the current-sheet can be a major factor affecting the strength of the detected signals. The purpose of the present study is, therefore, to perform a detailed investigation on the effect of the material properties of the current-sheet on the detected signal strength and to establish a simple theoretical model for the detection mechanism

Grothendieck groups and a categorification of additive invariants

A topologically-invariant and additive homology class is mostly not a natural transformation as it is. In this paper we discuss turning such a homology class into a natural transformation; i.e., a "categorification" of it. In a general categorical set-up we introduce a generalized relative Grothendieck group from a cospan of functors of categories and also consider a categorification of additive invariants on objects. As an example, we obtain a general theory of characteristic homology classes of singular varieties.Comment: 27 pages, to appear in International J. Mathematic