国际工程投标报价方法与技巧

国际投标竞争的胜负不仅取决于各投标商的实力，也取决于投标商的报价编制方法与投标技巧运用是否得当。因此，投标单位应针对工程的实际情况，凭借自己的实力，并正确运用投标报价方法与技巧来达到中标的目的，从而给企业带来较好的经济效益和社会效益。     

An Efficient Restrictive Blind Signature Scheme with Applications to Electronic Cash

In this paper, a new restrictive blind signature scheme is proposed. Compared with Brands restrictive blind signature scheme, our scheme is even more restrictive and efficient. And our scheme is proved secure, too. A new withdrawal protocol of electronic cash system is designed by using our restrictive blind signature scheme, which is more efficient than the withdrawal protocol and is more appropriate for adopting pre-processing and post-processing.     

General Laws of Contemporary Science Development and Our Countermeasures

A general law of the development of science is from material science, information science to mental science, and from material science, life science to human science. We should enlarge the input for researching of information science and life science because they reflect the developing tendency of the science.     

Governing Equation and Mathematical Simulation on Ablation and Transpiration Control

This paper represents a physical model of two -dimensional transpiration cooling control system with surface heating and ablating. The governing equation is derived and the third boundary conditions are given. They constitute a two -dimensional variable -domain distributed parameter control system in which the control parameter appears in both the governing equation and the boundary conditions. Applying time semi-step alternating direction method to difference this mathematical model, the tridiagonal difference equations are obtained. For a flying shell of electromagnetic railgun, the mathematical simulation results agree with the realistic physical process, and the control parameter not only can control the temperature of heat shield, but also can control the boundary motion effectively.     

Complete Nucleotide Sequence of a Newly Avirulent Newcastle Disease Virus Hubei 92(HB92) Strain

Newcastledisease (ND )isaseriousaviandiseasewithworldwidedistributionthatcancausesevereeconomicloss esinthepoultryindustry .Thecausativeagentofthedisease ,newcastlediseasevirus(NDV)alsoknownasavianParamyxovirustype 1,isamemberoftheParamyxoviridaeandcontainsasin gle strandednegativesenseRNAgenomeencompassing 15 186nucleotides[1 3] .Theviralgenomecontainssixgenes ,whichen codetheviralnucleoprotein(NP) ,phosphoprotein(P) ,matrixprotein(M ) ,fusionprotein (F) ,hemagglutinin neuraminidase(HN…     

DNA sequence and analysis of human chromosome 18

Chromosome 18 appears to have the lowest gene density of any human chromosome and is one of only three chromosomes for which trisomic individuals survive to term. There are also a number of genetic disorders stemming from chromosome 18 trisomy and aneuploidy. Here we report the finished sequence and gene annotation of human chromosome 18, which will allow a better understanding of the normal and disease biology of this chromosome. Despite the low density of protein-coding genes on chromosome 18, we find that the proportion of non-protein-coding sequences evolutionarily conserved among mammals is close to the genome-wide average. Extending this analysis to the entire human genome, we find that the density of conserved non-protein-coding sequences is largely uncorrelated with gene density. This has important implications for the nature and roles of non-protein-coding sequence elements.     

R gene expression induced by a type-III effector triggers disease resistance in rice

Disease resistance (R) genes in plants encode products that specifically recognise incompatible pathogens and trigger a cascade of events leading to disease resistance in the host plant. R-gene specificity is dictated by both host R genes and cognate avirulence (avr) genes in pathogens. However, the basis of gene-for-gene specificity is not well understood. Here, we report the cloning of the R gene Xa27 from rice and the cognate avr gene avrXa27 from Xanthomonas oryzae pv. oryzae. Resistant and susceptible alleles of Xa27 encode identical proteins. However, expression of only the resistant allele occurs when a rice plant is challenged by bacteria harbouring avrXa27, whose product is a nuclear localized type-III effector. Induction of Xa27 occurs only in the immediate vicinity of infected tissue, whereas ectopic expression of Xa27 resulted in resistance to otherwise compatible strains of the pathogen. Thus Xa27 specificity towards incompatible pathogens involves the differential expression of the R gene in the presence of the AvrXa27 effector.     

Calcium-sensitive potassium channelopathy in human epilepsy and paroxysmal movement disorder

The large conductance calcium-sensitive potassium (BK) channel is widely expressed in many organs and tissues, but its in vivo physiological functions have not been fully defined. Here we report a genetic locus associated with a human syndrome of coexistent generalized epilepsy and paroxysmal dyskinesia on chromosome 10q22 and show that a mutation of the alpha subunit of the BK channel causes this syndrome. The mutant BK channel had a markedly greater macroscopic current. Single-channel recordings showed an increase in open-channel probability due to a three- to fivefold increase in Ca(2+) sensitivity. We propose that enhancement of BK channels in vivo leads to increased excitability by inducing rapid repolarization of action potentials, resulting in generalized epilepsy and paroxysmal dyskinesia by allowing neurons to fire at a faster rate. These results identify a gene that is mutated in generalized epilepsy and paroxysmal dyskinesia and have implications for the pathogenesis of human epilepsy, the neurophysiology of paroxysmal movement disorders and the role of BK channels in neurological disease.     

Comparative mapping of QTLs for Al tolerance in rice and identification of positional Al-induced genes

Aluminum (A1) toxicity is the major factor limiting crop productivity in acid soils. In this study, a recombinant inbreed line (RIL) population derived from a cross between an A1 sensitive lowland indica rice variety IR1552 and an A1 tolerant upland japonica rice variety Azucena, was used for mapping quantitative trait loci (QTLs) for A1 tolerance. Three QTLs for relative root length (RRL) were detected on chromosome 1,9, 12, respectively, and 1 QTL for root length under A1 stress is identical on chromosome 1 after one week and two weeks stress. Comparison of QTLs on chromosome 1 from different studies indicated an identical interval between C86 and RZ801 with gene(s) for A1 tolerance. This interval provides an important start point for isolating genes responsible for A1 tolerance and understanding the genetic nature of Al tolerance in rice. Four A1 induced ESTs located in this interval were screened by reverse Northern analysis and confirmed by Northern analysis. They would be candidate genes for the QTL.     

Off-pump coronary artery bypass grafting versus on-pump coronary artery bypass grafting： which is better in patients with chronic obstructive pulmonary disease？

To evaluate the clinic outcome of off-pump coronary bypass grafting (OPCABG) of patients with coronary heart disease and chronic obstructive pulmonary disease, we collected and analyzed 1998-2002 data on 28 patients with these two diseases who had received off-pump coronary bypass operation in our hospital, and compared with data on those who also had the same two diseases but received on-pump coronary artery bypass at same time. There were no operation-related death;one died of respiratory failure 14 days after operation while staying in hospital; there were more respiratory complications in the conventional coronary artery bypass grafting group (CCABG) than in the OPCABG group; and the PaO2/FiO2 in the CCABG group was higher than that in the OPCABG group during operation because of CPB, but lower than that in the OPCABG group 6-12 hours after operation. OPCABG seemed more suitable than CCABG for coronary artery disease patients with chronic obstructive pulmonary disease due to less damage to their oxygen-exchange capability and the fewer respiratory complications.