The dependency diagram of a mixed integer linear programme

The Dependency Diagram of a Linear Programme (LP) shows how the successive inequalities of an LP depend on former inequalities, when variables are projected out by Fourier- Motzkin Elimination. This is explained in a paper referenced below. The paper, given here, extends the results to the Mixed Integer case (MILP). It is shown how projection of a MILP leads to a finite disjunction of polytopes. This is expressed as a set of inequalities (mirroring those in the LP case) augmented by correction terms with finite domains which are subject to linear congruences

Monolayers of 3He on the Surface of Bulk Superfluid 4He

We have used quantum evaporation to investigate the two-dimensional fermion system that forms at the free surface of (initially isotopically pure) 4He when small quantities of 3He are added to it. By measuring the first-arrival times of the evaporated atoms, we have determined that the 3He-3He potential in this system is V_3S/k_B=(0.23+/-0.02) K nm^2 (repulsive) and estimated a value of m_3S=(1.53+/-0.02)m_3 for the zero-coverage effective mass. We have also observed the predicted second layer-state which becomes occupied once the first layer-state density exceeds about 0.6 monolayers.Comment: 2 pages, 3 figures. Submitted to Proc. LT-22 (1999) to appear in Physica

Mapping biodiversity value worldwide: combining higher-taxon richness from different groups

Maps of large-scale biodiversity are urgently needed to guide conservation, and yet complete enumeration of organisms is impractical at present. One indirect approach is to measure richness at higher taxonomic ranks, such as families. The difficulty is how to combine information from different groups on numbers of higher taxa, when these taxa may in effect have been defined in different ways, particularly for more distantly related major groups. In this paper, the regional family richness of terrestrial and freshwater seed plants, amphibians, reptiles and mammals is mapped worldwide by combining: (i) absolute family richness; (ii) proportional family richness; and (iii) proportional family richness weighted for the total species richness in each major group. The assumptions of the three methods and their effects on the results are discussed, although for these data the broad pattern is surprisingly robust with respect to the method of combination. Scores from each of the methods of combining families are used to rank the top five richness hotspots and complementary areas, and hotspots of endemism are mapped by unweighted combination of range-size rarity scores

Relative Evaporation Probabilities of 3He and 4He from the Surface of Superfluid 4He

We report a preliminary experiment which demonstrates that 3He atoms in Andreev states are evaporated by high-energy (E/k_B ~ 10.2 K) phonons in a quantum evaporation process similar to that which occurs in pure 4He. Under conditions of low 3He coverage, high-energy phonons appear to evaporate 3He and 4He atoms with equal probability. However, we have not managed to detect any 3He atoms that have been evaporated by rotons, and conclude that the probability of a roton evaporating a 3He atom is less than 2% of the probability that it evaporates a 4He atom.Comment: 2 pages, 3 figures. Submitted to Proc. LT-22 (1999) Physica

Action perception is intact in autism spectrum disorder

Date of Acceptance:10/11/2014. Copyright © 2015 the authors 0270-6474/15/351849-09$15.00/0. Copyright of all material published in The Journal of Neuroscience remains with the authors. The authors grant the Society for Neuroscience an exclusive license to publish their work for the first 6 months. After 6 months the work becomes available to the public to copy, distribute, or display under a Creative Commons Attribution 4.0 International (CC BY 4.0) license.Peer reviewedPublisher PD

Deterministic dense coding and entanglement entropy

We present an analytical study of the standard two-party deterministic dense-coding protocol, under which communication of perfectly distinguishable messages takes place via a qudit from a pair of non-maximally entangled qudits in pure state |S>. Our results include the following: (i) We prove that it is possible for a state |S> with lower entanglement entropy to support the sending of a greater number of perfectly distinguishable messages than one with higher entanglement entropy, confirming a result suggested via numerical analysis in Mozes et al. [Phys. Rev. A 71 012311 (2005)]. (ii) By explicit construction of families of local unitary operators, we verify, for dimensions d = 3 and d=4, a conjecture of Mozes et al. about the minimum entanglement entropy that supports the sending of d + j messages, j = 2, ..., d-1; moreover, we show that the j=2 and j= d-1 cases of the conjecture are valid in all dimensions. (iii) Given that |S> allows the sending of K messages and has the square roof of c as its largest Schmidt coefficient, we show that the inequality c <= d/K, established by Wu et al. [ Phys. Rev. A 73, 042311 (2006)], must actually take the form c < d/K if K = d+1, while our constructions of local unitaries show that equality can be realized if K = d+2 or K = 2d-1.Comment: 19 pages, 2 figures. Published versio

Constitutive acoustic-emission elastic-stress behavior of magnesium alloy

Repeated laoding and unloading of a magnesium alloy below the macroscopic yield stress result in continuous acoustic emissions which are generally repeatable for a given specimen and which are reproducible between different specimens having the same load history. An acoustic emission Bauschinger strain model is proposed to describe the unloading emission behavior. For the limited range of stress examined, loading and unloading stress delays of the order of 50 MN/sq m are observed, and they appear to be dependent upon the direction of loading, the stress rate, and the stress history. The stress delay is hypothesized to be the manifestation of an effective friction stress. The existence of acoustic emission elastic stress constitutive relations is concluded, which provides support for a previously proposed concept for the monitoring of elastic stresses by acoustic emission

Non-parametric Reconstruction of Cluster Mass Distribution from Strong Lensing: Modelling Abell 370

We describe a new non-parametric technique for reconstructing the mass distribution in galaxy clusters with strong lensing, i.e., from multiple images of background galaxies. The observed positions and redshifts of the images are considered as rigid constraints and through the lens (ray-trace) equation they provide us with linear constraint equations. These constraints confine the mass distribution to some allowed region, which is then found by linear programming. Within this allowed region we study in detail the mass distribution with minimum mass-to-light variation; also some others, such as the smoothest mass distribution. The method is applied to the extensively studied cluster Abell 370, which hosts a giant luminous arc and several other multiply imaged background galaxies. Our mass maps are constrained by the observed positions and redshifts (spectroscopic or model-inferred by previous authors) of the giant arc and multiple image systems. The reconstructed maps obtained for \a370 reveal a detailed mass distribution, with substructure quite different from the light distribution. The method predicts the bimodal nature of the cluster and that the projected mass distribution is indeed elongated along the axis defined by the two dominant cD galaxies. But the peaks in the mass distribution appear to be offset from the centres of the cDs. We also present an estimate for the total mass of the central region of the cluster. This is in good agreement with previous mass determinations. The total mass of the central region is M=(2.0-2.7) 10^14 Msun/h50, depending on the solution chosen.Comment: 14 pages(19 postscript figures), minor corrections, MNRAS in pres