Some zero rest mass test fields in general relativity

Zero rest mass test fields of pure algebraic type are defined and studied via the newly developed GHP formalism. The field equations are written explicitly and an immediate generalisation of Robinson's theorem is obtained. The form for the general zero rest mass test field of pure type is determined in terms of the tetrad components of the background Weyl spinor and an additional gauge dependent function which can be thought of as representing a test neutrino field.     

温度限制串联相关神经网络及其在细菌辨识中的应用

蛋白质在微生物研究中可用作生物标记物,故在生物技术中其表征工作很重要．各种质谱技术已被用于细菌的表征[‘－’j．1994年,Cain等[‘]首先报道了将色谱和基体辅助激光解离/电离飞行时间质谱(M     

The effect of a phosphorus bridgehead atom on the loss of neutral species in the mass spectra of bicyclooctanes

The effect of a bridgehead phosphorus atom, as both the three (phosphate)and five (phosphate) oxidation states, to influence unique mass spectral neutral losses from a 1-phosphabicyclo[2.2.2]octane system has been investigated. A conventional neutral loss of formaldehyde was found for the phosphites while a unique loss of ethylene was observed for the phosphate. These losses are discussed in terms of the substituent effects from the 4-position.     

On-probe sample pretreatment for the detection of proteins above 15 KDa from whole cell bacteria by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

A rapid methodology is described for the enhancement of the signal-to-base-line (S/B) ratio of high molecular weight protein signals from whole cell bacteria analyzed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS). The procedure involves depositing growing bacteria colonies from culture dishes directly onto the MALDI probe followed by treatment of the sample spot with a 2 microL aliquot of 40% ethanol prior to the addition of a ferulic acid matrix solution (12.5 mg dissolved in 17% formic acid/33% acetonitrile/50% H(2)O). Protein signals of more than 20 kDa were routinely produced from both Gram positive and Gram negative bacteria prepared in this manner. Moreover, a substantial number of intense protein signals were also produced in the more 'conventional' fingerprint region extending from 4 to 20 kDa. This approach is rapid, easy to implement into existing methodologies, and does not require any special hardware.     

Emergence and induction of cellular automata rules via probabilistic reinforcement paradigms

Two simple models of emergence and automated induction are described. In the first, an initially random process comes, over time, to emulate a deterministic process with noise. In the second, an induction algorithm is used to make unbiased best guess estimates of cellular automata rules generating a given time series of binary strings. The general conclusions are as follows: (1) that it may not be possible to distinguish between a stochastic process with selection and reinforcement and a noisy deterministic process; and (2) automated induction algorithms will often be vulnerable to errors of type 1 when faced with random data. In this second case, this leads to a method for study of the modeling class assumed in the induction algorithm. © 2006 Wiley Periodicals, Inc. Complexity 11: 44–57, 2006