12,344 research outputs found

    Computations on Sofic S-gap Shifts

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    Let S={sn}S=\{s_{n}\} be an increasing finite or infinite subset of N⋃{0}\mathbb N \bigcup \{0\} and X(S)X(S) the SS-gap shift associated to SS. Let fS(x)=1βˆ’βˆ‘1xsn+1f_{S}(x)=1-\sum\frac{1}{x^{s_{n}+1}} be the entropy function which will be vanished at 2h(X(S))2^{h(X(S))} where h(X(S))h(X(S)) is the entropy of the system. Suppose X(S)X(S) is sofic with adjacency matrix AA and the characteristic polynomial Ο‡A\chi_{A}. Then for some rational function QS Q_{S} , Ο‡A(x)=QS(x)fS(x)\chi_{A}(x)=Q_{S}(x)f_{S}(x). This QS Q_{S} will be explicitly determined. We will show that ΞΆ(t)=1fS(tβˆ’1)\zeta(t)=\frac{1}{f_{S}(t^{-1})} or ΞΆ(t)=1(1βˆ’t)fS(tβˆ’1)\zeta(t)=\frac{1}{(1-t)f_{S}(t^{-1})} when ∣S∣<∞|S|<\infty or ∣S∣=∞|S|=\infty respectively. Here ΞΆ\zeta is the zeta function of X(S)X(S). We will also compute the Bowen-Franks groups of a sofic SS-gap shift.Comment: This paper has been withdrawn due to extending results about SFT shifts to sofic shifts (Theorem 2.3). This forces to apply some minor changes in the organization of the paper. This paper has been withdrawn due to a flaw in the description of the adjacency matrix (2.3

    Do We See Eye to Eye? Moderators of Correspondence Between Student and Faculty Evaluations of Day-to-Day Teaching

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    Students and instructors show moderate levels of agreement about the quality of day-to-day teaching. In the present study, we replicated and extended this finding by asking how correspondence between student and instructor ratings is moderated by time of semester and student demographic variables. Participants included 137 students and 5 instructors. On 10 separate days, students and instructors rated teaching effectiveness and challenge level of the material. Multilevel modeling indicated that student and instructor ratings of teaching effectiveness converged overall, but more advanced students and Caucasian students converged more closely with instructors. Student and instructor ratings of challenge converged early but diverged later in the semester. These results extend our knowledge about the connection between student and faculty judgments of teaching

    Hardware and software status of QCDOC

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    QCDOC is a massively parallel supercomputer whose processing nodes are based on an application-specific integrated circuit (ASIC). This ASIC was custom-designed so that crucial lattice QCD kernels achieve an overall sustained performance of 50% on machines with several 10,000 nodes. This strong scalability, together with low power consumption and a price/performance ratio of $1 per sustained MFlops, enable QCDOC to attack the most demanding lattice QCD problems. The first ASICs became available in June of 2003, and the testing performed so far has shown all systems functioning according to specification. We review the hardware and software status of QCDOC and present performance figures obtained in real hardware as well as in simulation.Comment: Lattice2003(machine), 6 pages, 5 figure

    Haplotype analysis of the PPARgamma Pro12Ala and C1431T variants reveals opposing associations with body weight.

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    BACKGROUND: Variation at the PPARG locus may influence susceptibility to type 2 diabetes and related traits. The Pro12Ala polymorphism may modulate receptor activity and is associated with protection from type 2 diabetes. However, there have been inconsistent reports of its association with obesity. The silent C1431T polymorphism has not been as extensively studied, but the rare T allele has also been inconsistently linked to increases in weight. Both rare alleles are in linkage disequilibrium and the independent associations of these two polymorphisms have not been addressed. RESULTS: We have genotyped a large population with type 2 diabetes (n = 1107), two populations of non-diabetics from Glasgow (n = 186) and Dundee (n = 254) and also a healthy group undergoing physical training (n = 148) and investigated the association of genotype with body mass index. This analysis has demonstrated that the Ala12 and T1431 alleles are present together in approximately 70% of the carriers. By considering the other 30% of individuals with haplotypes that only carry one of these polymorphisms, we have demonstrated that the Ala12 allele is consistently associated with a lower BMI, whilst the T1431 allele is consistently associated with higher BMI. CONCLUSION: This study has therefore revealed an opposing interaction of these polymorphisms, which may help to explain previous inconsistencies in the association of PPARG polymorphisms and body weight

    The Fall of the Quasar Population

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    We derive quantitative predictions of the optical and X-ray luminosity functions (LF) for QSs in the redshift range z<3z<3. Based on BH paradigm, we investigate how the accretion is controlled by the surrounding structures, as these grow hierarchically. We argue that for z<3z < 3 efficient black hole fueling is triggered by the encounters of a gas-rich host with its companions in a group. The dispersion of the dynamical parameters in the encounters produces a double power-law LF. Strong luminosity evolution (LE) is produced as these encounters deplete the gas supply in the host; an additional, milder density evolution obtains since the interactions become progressively rarer as the groups grow richer but less dense. From the agreement with the optical and the X-ray data, we conclude that the evolution of the bright quasars is articulated in two ways. Earlier than zΒ 3z~3 the gas-rich protogalaxies grow by merging, which also induces parallel growth of central holes accreting at Eddington rates. In the later era of group assemblage the host encounters with companions drive onto already existing holes further but meager accretion; these consume the gas in the hosts, and cause supply-limited emissions which are intermittent, go progressively sub-Eddington and peter out. Then other fueling processes come to the foreground; we discuss the faint emissions, especially noticeable in X-rays, which are expected when hosts in the field cannibalize satellite galaxies with their meager gas contents.Comment: 12 pages Latex + 3 EPS figures, ApJ in press, we have corrected the previous printing problems with the style \ca
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