High-TcT_c mechanism through analysis of diverging effective mass for YaBa2_2Cu3_3O6+x_{6+x} and pairing symmetry in cuprate superconductors

In order to clarify the high-$T_c$ mechanism in inhomogeneous cuprate layer superconductors, we deduce and find the correlation strength not revealed before, contributing to the formation of the Cooper pair and the 2-D density of state, and demonstrate the pairing symmetry in the superconductors still controversial. To the open questions, the fitting and analysis of the diverging effective mass with decreasing doping, extracted from the acquired quantum-oscillation data in underdoped YBCOO$_{6+x}$ superconductors, can provide solutions. Here, the results of the fitting using the extended Brinkman-Rice(BR) picture reveal the nodal constant Fermi energy with the maximum carrier density, a constant Coulomb correlation strength $k_{BR}$=$U/U_c$>0.90, and a growing Fermi arc from the nodal Fermi point to the isotropic Fermi surface with an increasing $x$. The growing of the Fermi arc indicates that a superconducting gap develops with $x$ from the node to the anti-node. The large $k_{BR}$ results from the $d$-wave MIT for the pseudogap phase in lightly doped superconductors, which can be direct evidence for high-$T_c$ superconductivity. The quantum critical point is regarded as the nodal Fermi point satisfied with the BR picture. The experimentally-measured mass diverging behavior is an average effect and the true effective mass is constant. As an application of the nodal constant carrier density, to find a superconducting node gap, the ARPES data and tunneling data are analyzed. The superconducting node gap is a precursor of $s$-wave symmetry in underdoped cuprates. The half-flux quantum, induced by the circulation of $d$-wave supercurrent and observed by the phase sensitive Josephson-pi junction experiments, is not shown due to anisotropic or asymmetric effect appearing in superconductors with trapped flux. The absence of $d$-wave superconducting pairing symmetry is also revealed.Comment: 19 pages, 21 figure

Impacts and Losses Caused By the Fraudulent and Manipulated Financial Information on Economic Decisions

Nowadays the effects of the fraudulent and manipulated financial information have been more controversial. We should take into consideration that the financial losses caused by fraudulent or manipulated financial information are remarkable. Preventing the fraud in the financial information has been an important issue by auditors all over the world. As the American economy is the dominant economy may cause and affect the capital market mostly all over the world. In the last decade we can see the financial losses caused by the fraudulent and manipulated financial information rather big. Today’s world has been affected by frauds and manipulation of the financial information. An investment decision based on false financial information causes the investors to suffer losses as was experienced in Enron and WorldCom cases. Financial information has, certainly, an important positive or negative effect in economic decisions. Positive or negative effects of financial information on economic decisions depend on reliability of the financial information. This paper aims to show the impacts of fraudulent on the financial information, effects on economic decision and what we should do for preventing the fraudulent or manipulation on the financial information.Financial information, fraudulent, manipulation, decision.

The first results from the Herschel-HIFI mission

This paper contains a summary of the results from the first years of observations with the HIFI instrument onboard ESA's Herschel space observatory. The paper starts by outlining the goals and possibilities of far-infrared and submillimeter astronomy, the limitations of the Earth's atmosphere, and the scientific scope of the Herschel-HIFI mission. The presentation of science results from the mission follows the life cycle of gas in galaxies as grouped into five themes: Structure of the interstellar medium, First steps in interstellar chemistry, Formation of stars and planets, Solar system results and Evolved stellar envelopes. The HIFI observations paint a picture where the interstellar medium in galaxies has a mixed, rather than a layered structure; the same conclusion may hold for protoplanetary disks. In addition, the HIFI data show that exchange of matter between comets and asteroids with planets and moons plays a large role. The paper concludes with an outlook to future instrumentation in the far-infrared and submillimeter wavelength ranges.Comment: Invited review paper to appear in Advances of Space Research; 32 pages, 9 figures. See http://www.sron.rug.nl/~vdtak/adspres.pdf for a 14-page journal-style versio

Space station software reliability analysis based on failures observed during testing at the multisystem integration facility

Quality of software not only is vital to the successful operation of the space station, it is also an important factor in establishing testing requirements, time needed for software verification and integration as well as launching schedules for the space station. Defense of management decisions can be greatly strengthened by combining engineering judgments with statistical analysis. Unlike hardware, software has the characteristics of no wearout and costly redundancies, thus making traditional statistical analysis not suitable in evaluating reliability of software. A statistical model was developed to provide a representation of the number as well as types of failures occur during software testing and verification. From this model, quantitative measure of software reliability based on failure history during testing are derived. Criteria to terminate testing based on reliability objectives and methods to estimate the expected number of fixings required are also presented

'Fire hardening' spear wood does slightly harden it, but makes it much weaker and more brittle

It is usually assumed that 'fire hardening' the tips of spears, as practised by hunter-gatherers and early Homo spp., makes them harder and better suited for hunting. This suggestion was tested by subjecting coppiced poles of hazel to a fire-hardening process and comparing their mechanical properties to those of naturally seasoned poles. A Shore D hardness test showed that fire treatment slightly increased the hardness of the wood, but flexural and impact tests showed that it reduced the strength and work of fracture by 30% and 36%, respectively. These results suggest that though potentially slightly sharper and more durable, fire-hardened tips would actually be more likely to break off when used, as may have been the case with the earliest known wooden tool, the Clacton spear. Fire might first have been used to help sharpen the tips of spears, and fire-hardening would have been a mostly negative side effect, not its primary purpose