QCD thermal phase transition in the presence of a small chemical potential

We propose a new method to investigate the thermal properties of QCD with a small quark chemical potential mu. Derivatives of quark and gluonic observables with respect to mu are computed at mu=0 for two flavors of p4 improved staggered fermions with ma=0.1,0.2 on a 16(3)x4 lattice, and used to calculate the leading order Taylor expansion in mu of the location of the pseudocritical point about mu=0. This expansion should be well behaved for the small values of mu(q)/T(c)similar to0.1 relevant for BNL RHIC phenomenology, and predicts a critical curve T-c(mu) in reasonable agreement with estimates obtained using exact reweighting. In addition, we contrast the case of isoscalar and isovector chemical potentials, quantify the effect of munot equal0 on the equation of state, and comment on the complex phase of the fermion determinant in QCD with munot equal0.

The intuitive basis of implicature: relevance theoretic implicitness versus gricean implying

The notion of implicature was first introduced by Paul Grice (1967, 1989), who defined it essentially as what is communicated less what is said. This definition contributed in part to the proliferation of a large number of different species of implicature by neo-Griceans. Relevance theorists have responded to this by proposing a shift back to the distinction between "explicit" & "implicit" meaning (corresponding to "explicature" & "implicature," respectively). However, they appear to have pared down the concept of implicature too much, ignoring phenomena that may be better treated as implicatures in their overgeneralization of the concept of explicature. These problems have their roots in the fact that explicit & implicit meaning intuitively overlap & thus do not provide a suitable basis for distinguishing implicature from other types of pragmatic phenomena. An alternative conceptualization of implicature based on the concept of "implying" with which Grice originally associated his notion of implicature is thus proposed. From this definition, it emerges that implicature constitutes something else inferred by the addressee that is not literally said by the speaker. Instead, it is meant in addition to what the speaker literally says & is consequently defeasible like all other types of pragmatic phenomena. 1 Figure, 60 References. Adapted from the source document

Exogenous Slit2 does not affect ureteric branching or nephron formation during kidney development

In an attempt to elucidate the role of Slit2 invertebrate kidney development, the effect of adding exogenous human Slit2 protein (hSlit2) to developing murine metanephric kidney explants was examined. To confirm the activity of the recombinant Slit2 protein, neurons from 8 day old chick sympathetic nerve chain dorsal root ganglia were cultured with hSlit2 protein, which induced significant neurite branching and outgrowth. Using kidney explants as a model system, metanephric development in the presence of hSlit2 protein was examined. Addition of hSlit2 up to a final concentration of 1 mug/ml had no detectable effect on the formation of nephrons or on branching morphogenesis of the ureteric tree after 2 or 4 days in culture, as assessed via immunofluorescence for the markers WT1 and calbindin 28K respectively. Similarly, maturation of the nephrogenic mesenchyme occurred in a phenotypically normal fashion. In situ analysis of the Slit receptors, Robot and Robot, the vasculogenic markers VEGFA and Flk-1, and the stromal cell marker BF2 displayed no difference in comparison to controls.

Practices and attitudes to derivatives use in Australian commonwealth organisations

Little is known about risk management in the public sector This study reports on a survey of senior officers in Australian Commonwealth companies and statutory authorities concerning their practice and attitudes towards the use of derivative instruments for risk management. Using a variety of tests, the most important issue identified by respondents concerning the use of derivatives is for budgeting purposes. Of note, respondents rank commonly cited reasons advanced in the private sector such as reduced bankruptcy costs and taxation, as being relatively unimportant, which is consistent with arguments advanced in the paper The results also indicate that there are significant differences in the level of importance in some issues regarding derivatives use across public sector organisations, particularly those differentiated by a documented risk management plan. The study also documents for the first time the extent of derivatives use in the Australian public sector.

Relations between high and low power groups: The importance of legitimacy

Using a social identity perspective, two experiments examined the effects of power and the legitimacy of power differentials on intergroup bias. In Experiment 1, 125 math-science students were led to believe that they had high or low representation in a university decision-making body relative to social-science students and that this power position was either legitimate or illegitimate. Power did not have an independent effect on bias; rather, members of both high and low power groups showed more bias when the power hierarchy was illegitimate than when it was legitimate. This effect was replicated in Experiment 2 (N =105). In addition, Experiment 2 showed that groups located within an unfair power hierarchy expected the superordinate power body to be more discriminatory than did those who had legitimately high or low power. The results are discussed in terms of their implications for group relations.

Fas ligand and tumour counter-attack in colorectal cancer stratified according to microsatellite instability status

Expression of membrane-bound Fas ligand (FasL) by colorectal cancer cells may allow the development of an immune-privileged site by eliminating incoming tumour-infiltrating lymphocytes (TILs) in a Fas-mediated counter-attack. Sporadic colorectal cancer can be subdivided into three groups based on the level of DNA microsatellite instability (NISI). High-level NISI (NISI-High) is characterized by the presence of TILs and a favourable prognosis, while microsatellite-stable (MSS) cancers are TIL-deficient and low-level MSI (MSI-Low) is associated with an intermediate TIL density. The purpose of this study was to establish the relationship between MSI status and FasL expression in primary colorectal adenocarcinoma. Using immunohistochemistry and a selected series of 101 cancers previously classified as 31 MSI-High, 30 NISI-Low, and 40 MISS, the present study sought to confirm the hypothesis that increased TIL density in MSI-High cancers is associated with low or absent membrane-bound FasL expression, while increased FasL in MSS cancers allows the killing of host TILs. TUNEL/CD3 double staining was also used to determine whether MSS cancers contain higher numbers of apoptotic TILs in vivo than MSI-High or MSI-Low cancers. Contrary to the initial hypothesis, it was found that MSI-High cancers were associated with higher FasL expression (p = 0.04) and a stronger intensity of FasL staining (p = 0.007). In addition, mucinous carcinomas were independently characterized by increased FasL expression (p = 0.03) and staining intensity (p = 0.0005). Higher FasL expression and staining intensity did not correlate with reduced TIL density or increased numbers of apoptotic TILs. However, consistent with the hypothesis that curtailment of the host anti-tumour immune response contributes to the poor prognosis in MSS cancers, it was found that apoptotic TILs were most abundant in MSS carcinomas and metastatic Dukes' stage C or D tumours (p = 0.004; p = 0.046 respectively). This study therefore suggests that MSS colorectal cancers are killing incoming TILs in an effective tumour counter-attack, but apparently not via membrane-bound FasL. Copyright (C) 2003 John Wiley Sons, Ltd.

Effect of Co addition on the lattice parameter, electrical conductivity and sintering of gadolinia-doped ceria

Co-sintering aid has been added to Ce1.9Gd0.1O1.95 (CGO) by treating a commercial powder with Co(NO3)(2) (COCGO), X-ray diffraction (XRD) measurements of lattice parameter indicated that the Co was located on the CGO particle surface after calcination at 650 degreesC. After heat treatment at temperatures above 650 degreesC, the room temperature lattice parameter of CGO was found to increase, indicating redistribution of the Gd. Compared to CGO, the lattice parameter of CGO + 2 cation% Co (2CoCGO) was lower for a given temperature (650-1100 degreesC), A.C. impedance revealed that the lattice conductivity of 2CoCGO was enhanced when densified at lower temperatures, Transmission electron microscopy (TEM) showed that, even after sintering for 4 h at 980 degreesC, most of the Co was located at grain boundaries. (C) 2002 Published by Elsevier Science B.V.

A unified model of flames as gasdynamic discontinuities

Viewed on a hydrodynamic scale, flames in experiments are often thin so that they may be described as gasdynamic discontinuities separating the dense cold fresh mixture from the light hot burned products. The original model of a flame as a gasdynamic discontinuity was due to Darrieus and to Landau. In addition to the fluid dynamical equations, the model consists of a flame speed relation describing the evolution of the discontinuity surface, and jump conditions across the surface which relate the fluid variables on the two sides of the surface. The Darrieus-Landau model predicts, in contrast to observations, that a uniformly propagating planar flame is absolutely unstable and that the strength of the instability grows with increasing perturbation wavenumber so that there is no high-wavenumber cutoff of the instability. The model was modified by Markstein to exhibit a high-wavenumber cutoff if a phenomenological constant in the model has an appropriate sign. Both models are postulated, rather than derived from first principles, and both ignore the flame structure, which depends on chemical kinetics and transport processes within the flame. At present, there are two models which have been derived, rather than postulated, and which are valid in two non-overlapping regions of parameter space. Sivashinsky derived a generalization of the Darrieus-Landau model which is valid for Lewis numbers (ratio of thermal diffusivity to mass diffusivity of the deficient reaction component) bounded away from unity. Matalon & Matkowsky derived a model valid for Lewis numbers close to unity. Each model has its own advantages and disadvantages. Under appropriate conditions the Matalon-Matkowsky model exhibits a high-wavenumber cutoff of the Darrieus-Landau instability. However, since the Lewis numbers considered lie too close to unity, the Matalon-Matkowsky model does not capture the pulsating instability. The Sivashinsky model does capture the pulsating instability, but does not exhibit its high-wavenumber cutoff. In this paper, we derive a model consisting of a new flame speed relation and new jump conditions, which is valid for arbitrary Lewis numbers. It captures the pulsating instability and exhibits the high-wavenumber cutoff of all instabilities. The flame speed relation includes the effect of short wavelengths, not previously considered, which leads to stabilizing transverse surface diffusion terms.

A modified Weibull distribution

A new lifetime distribution capable of modeling a bathtub-shaped hazard-rate function is proposed. The proposed model is derived as a limiting case of the Beta Integrated Model and has both the Weibull distribution and Type I extreme value distribution as special cases. The model can be considered as another useful 3-parameter generalization of the Weibull distribution. An advantage of the model is that the model parameters can be estimated easily based on a Weibull probability paper (WPP) plot that serves as a tool for model identification. Model characterization based on the WPP plot is studied. A numerical example is provided and comparison with another Weibull extension, the exponentiated Weibull, is also discussed. The proposed model compares well with other competing models to fit data that exhibits a bathtub-shaped hazard-rate function.

Ataxia-telangiectasia-mutated (ATM) and NBS1-dependent phosphorylation of Chk1 on Ser-317 in response to ionizing radiation

In mammals, the ATM (ataxia-telangiectasia-mutated) and ATR (ATM and Rad3-related) protein kinases function as critical regulators of the cellular DNA damage response. The checkpoint functions of ATR and ATM are mediated, in part, by a pair of checkpoint effector kinases termed Chk1 and Chk2. In mammalian cells, evidence has been presented that Chk1 is devoted to the ATR signaling pathway and is modified by ATR in response to replication inhibition and UV-induced damage, whereas Chk2 functions primarily through ATM in response to ionizing radiation (IR), suggesting that Chk2 and Chk1 might have evolved to channel the DNA damage signal from ATM and ATR, respectively. We demonstrate here that the ATR-Chk1 and ATM-Chk2 pathways are not parallel branches of the DNA damage response pathway but instead show a high degree of cross-talk and connectivity. ATM does in fact signal to Chk1 in response to IR. Phosphorylation of Chk1 on Ser-317 in response to IR is ATM-dependent. We also show that functional NBS1 is required for phosphorylation of Chk1, indicating that NES1 might facilitate the access of Chk1 to ATM at the sites of DNA damage. Abrogation of Chk1 expression by RNA interference resulted in defects in IR-induced S and G2/M phase checkpoints; however, the overexpression of phosphorylation site mutant (S317A, S345A or S317A/S345A double mutant) Chk1 failed to interfere with these checkpoints. Surprisingly, the kinase-dead Chk1 (D130A) also failed to abrogate the S and G2 checkpoint through any obvious dominant negative effect toward endogenous Chk1. Therefore, further studies will be required to assess the contribution made by phosphorylation events to Chk1 regulation. Overall, the data presented in the study challenge the model in which Chk1 only functions downstream from ATR and indicate that ATM does signal to Chk1. In addition, this study also demonstrates that Chk1 is essential for IR-induced inhibition of DNA synthesis and the G2/M checkpoint.