2,471 research outputs found
Price Formation under Small Numbers Competition: Evidence from Land Auctions in Singapore
This paper examines the price formation process under small numbers competition using data from Singapore land auctions. The theory predicts that bid prices are less than the zero-profit asset value in these first-price sealed-bid auctions. The model also shows that expected sales price increases with the number of bidders both because each bidder has an incentive to offer a higher price and because of a greater likelihood that a high-value bidder is present. The empirical estimates are consistent with auction theory and show that the standard land attributes are reflected in auction prices as expected. Working Paper No. 04-0
Vortex Matter Transition in BiSrCaCuO under Tilted Fields
Vortex phase diagram under tilted fields from the axis in
BiSrCaCuO is studied by local magnetization
hysteresis measurements using Hall probes. When the field is applied at large
angles from the axis, an anomaly () other than the well-known
peak effect () are found at fields below . The angular dependence of
the field is nonmonotonic and clearly different from that of
and depends on the oxygen content of the crystal. The results suggest existence
of a vortex matter transition under tilted fields. Possible mechanisms of the
transition are discussed.Comment: Revtex, 4 pages, some corrections are adde
Rotational Cooling of Polar Molecules by Stark-tuned Cavity Resonance
A general scheme for rotational cooling of diatomic heteronuclear molecules
is proposed. It uses a superconducting microwave cavity to enhance the
spontaneous decay via Purcell effect. Rotational cooling can be induced by
sequentially tuning each rotational transition to cavity resonance, starting
from the highest transition level to the lowest using an electric field.
Electrostatic multipoles can be used to provide large confinement volume with
essentially homogeneous background electric field.Comment: 10 pages, 6 figure
Global Optimization by Energy Landscape Paving
We introduce a novel heuristic global optimization method, energy landscape
paving (ELP), which combines core ideas from energy surface deformation and
tabu search. In appropriate limits, ELP reduces to existing techniques. The
approach is very general and flexible and is illustrated here on two protein
folding problems. For these examples, the technique gives faster convergence to
the global minimum than previous approaches.Comment: to appear in Phys. Rev. Lett. (2002
Characteristics of predictor sets found using differential prioritization
<p>Abstract</p> <p>Background</p> <p>Feature selection plays an undeniably important role in classification problems involving high dimensional datasets such as microarray datasets. For filter-based feature selection, two well-known criteria used in forming predictor sets are relevance and redundancy. However, there is a third criterion which is at least as important as the other two in affecting the efficacy of the resulting predictor sets. This criterion is the degree of differential prioritization (DDP), which varies the emphases on relevance and redundancy depending on the value of the DDP. Previous empirical works on publicly available microarray datasets have confirmed the effectiveness of the DDP in molecular classification. We now propose to establish the fundamental strengths and merits of the DDP-based feature selection technique. This is to be done through a simulation study which involves vigorous analyses of the characteristics of predictor sets found using different values of the DDP from toy datasets designed to mimic real-life microarray datasets.</p> <p>Results</p> <p>A simulation study employing analytical measures such as the distance between classes before and after transformation using principal component analysis is implemented on toy datasets. From these analyses, the necessity of adjusting the differential prioritization based on the dataset of interest is established. This conclusion is supported by comparisons against both simplistic rank-based selection and state-of-the-art equal-priorities scoring methods, which demonstrates the superiority of the DDP-based feature selection technique. Reapplying similar analyses to real-life multiclass microarray datasets provides further confirmation of our findings and of the significance of the DDP for practical applications.</p> <p>Conclusion</p> <p>The findings have been achieved based on analytical evaluations, not empirical evaluation involving classifiers, thus providing further basis for the usefulness of the DDP and validating the need for unequal priorities on relevance and redundancy during feature selection for microarray datasets, especially highly multiclass datasets.</p
Glycerol residue - a rich source of glycerol and medium chain fatty acids
Glycerol residue, a by-product of glycerol refining from a palm kernel oil methyl ester plant, was found to be a good source of glycerol and medium chain fatty acids. From analyses of twelve samples, it was found to contain, on average, 20.2 % glycerol and 6.6 % fatty acids. The fatty acids comprised mainly C8:0 (30.3 %), C10:0 (9.4 %) and C12:0 (40.8 %)
Possible new vortex matter phases in BSCCO
The vortex matter phase diagram of BSCCO crystals is analyzed by
investigating vortex penetration through the surface barrier in the presence of
a transport current. The strength of the effective surface barrier, its
nonlinearity, and asymmetry are used to identify a possible new ordered phase
above the first-order transition. This technique also allows sensitive
determination of the depinning temperature. The solid phase below the
first-order transition is apparently subdivided into two phases by a vertical
line extending from the multicritical point.Comment: 11 pages, 3 figures, accepted for publication in PR
BISC: Binary SubComplexes in proteins database
Binary subcomplexes in proteins database (BISC) is a new protein–protein interaction (PPI) database linking up the two communities most active in their characterization: structural biology and functional genomics researchers. The BISC resource offers users (i) a structural perspective and related information about binary subcomplexes (i.e. physical direct interactions between proteins) that are either structurally characterized or modellable entries in the main functional genomics PPI databases BioGRID, IntAct and HPRD; (ii) selected web services to further investigate the validity of postulated PPI by inspection of their hypothetical modelled interfaces. Among other uses we envision that this resource can help identify possible false positive PPI in current database records. BISC is freely available at http://bisc.cse.ucsc.edu
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