Andr\'e-Quillen homology via functor homology

We obtain Andr\'e-Quillen homology for commutative algebras using relative homological algebra in the category of functors on finite pointed set

Testing general relativity during the cruise phase of the BepiColombo mission to Mercury

General relativity (GR) predicts that photons are delayed and deflected by the space curvature produced by any mass. The Post-Newtonian (PN) parameter controlling the curvature induced by a gravitational field is γ, with bending and delay effects proportional to (γ + 1). γ = 1 in GR. The most accurate estimation of this PN parameter γ = (1 + (2.1 ± 2.3)) · 10-5, has been obtained by the NASA mission Cassini [1] exploiting the frequency shift of radio signal during a Superior Solar Conjunction (SSC) in 2002, while the spacecraft was in cruise to Saturn. The crucial element of the experiment was an advanced radio system providing a highly stable multi-frequency radio link in X and Ka band (8.4 and 32.5 GHz), and a nearly complete cancellation of the plasma noise introduced by the solar corona in Doppler measurements. The ESA-JAXA mission BepiColombo to Mercury will improve the Cassini radio instrumentation by enabling the ranging function also in the Ka band radio link used by the Mercury Orbiter Radio science Experiment (MORE). The fully digital architecture of the transponder provides a pseudo-noie modulation of the carrier at 24 Mcps and a two-way range accuracy of 20 cm. Thanks to the simultaneous tracking by means of the standard telecommunication link, both range and range rate observables will be available for new, more accurate tests of GR. This paper reports on the simulations carried out in order to assess the attainable accuracies in the estimation of γ during the cruise phase of BepiColombo. In an optimal configuration, an uncertainty of 5·10-6 may be attained

Spacelab Users Guide: A Short Introduction to Spacelab and Its Use

Spacelab is an orbital facility that provides a pressurized, 'shirt-sleeve' laboratory (the module) and an unpressurized platform (the pallet), together with certain standard services. It is a reusable system, which is transported to and from orbit in the cargo bay of the space shuttle orbiter and remains there throughout the flight. Spacelab extends the shuttle capability, and the Orbiter/Spacelab combination can be regarded as a short-stay space station which can remain in orbit for up to 30 days (the nominal mission duration is 7 days). In orbit, the experiments carried by Spacelab are operated by a team of up to four payload specialists who normally work in the laboratory, but spend their off-duty time in the orbiter cabin. The purpose of Spacelab is to provide a ready access to space for a broad spectrum of experimenters in many fields and from many nations. Low-cost techniques are envisaged for experiment development, integration and operation. The aim of this document is to provide a brief summary of Spacelab design characteristics and its use potential for experimenters wishing to take advantage of the unique opportunities offered for space experimentation

Parallel computation with the force

A methodology, called the force, supports the construction of programs to be executed in parallel by a force of processes. The number of processes in the force is unspecified, but potentially very large. The force idea is embodied in a set of macros which produce multiproceossor FORTRAN code and has been studied on two shared memory multiprocessors of fairly different character. The method has simplified the writing of highly parallel programs within a limited class of parallel algorithms and is being extended to cover a broader class. The individual parallel constructs which comprise the force methodology are discussed. Of central concern are their semantics, implementation on different architectures and performance implications

Dataset of the Refrigerator Case: design of closed loop supply chains

This paper contains the dataset for the refrigerator case concerning the design of a production and return network for refrigerators. Section 1 emphasises the major changes to the problem structure and assumptions used by Umeda et al. (1999). Section 2 contains the parameter settings. Section 3 contains the distance matrix for all locations

Symplectomorphism groups and embeddings of balls into rational ruled 4-manifolds

Let $X$ be any rational ruled symplectic four-manifold. Given a symplectic embedding \iota:B_{c}\into X of the standard ball of capacity $c$ into $X$, consider the corresponding symplectic blow-up \tX_{\iota}. In this paper, we study the homotopy type of the symplectomorphism group \Symp(\tX_{\iota}), simplifying and extending the results of math.SG/0207096. This allows us to compute the rational homotopy groups of the space \IEmb(B_{c},X) of unparametrized symplectic embeddings of $B_{c}$ into $X$. We also show that the embedding space of one ball in $CP^2$, and the embedding space of two disjoint balls in $CP^2$, if non empty, are always homotopy equivalent to the corresponding spaces of ordered configurations. Our method relies on the theory of pseudo-holomorphic curves in 4-manifolds, on the theory of Gromov invariants, and on the inflation technique of Lalonde-McDuff.Comment: New title, new abstract, content now agrees with the published version, small correction to the proof of Theorem 1.10. A sequel to the paper SG/020709

CAMAC bulletin: A publication of the ESONE Committee Issue #14 December 1975 [last pub. of series]

CAMAC is a means of interconnecting many peripheral devices through a digital data highway to a data processing device such as a computer

Conformally equivariant second-order differential operators in dimension 1|2: Quantization and symbol calculus

11This paper is the next step of an ambitious program to develop conformally equivariant quantization on supermanifolds. This problem was considered so far in (super)dimensions 1 and 1|1. We will show that the case of several odd variables is much more difficult. We consider the supercircle $S^{1|2}$ equipped with the standard contact structure. The conformal Lie superalgebra K(2) of contact vector fields on $S^{1|2}$ contains the Lie superalgebra osp(2|2). We study the spaces of linear differential operators on the spaces of weighted densities as modules over osp(2|2). We prove that, in the non-resonant case, the spaces of second order differential operators are isomorphic to the corresponding spaces of symbols as osp(2|2)-modules. We also prove that the conformal equivariant quantization map is unique and calculate its explicit formula