First-principles calculations of lattice thermal conductivity in Tl,\u3csub\u3e3\u3c/sub\u3eVSe\u3csub\u3e4\u3c/sub\u3e: Uncertainties from different approaches of force constants

Accurate and reliable first-principles simulations of lattice thermal conductivity (κL) of highly anharmonic crystals have long been challenging in condensed matter and materials physics. With recent theoretical advances, the calculation of κL has evolved into a sophisticated process requiring the consideration of higher levels of refinements, such as high-order phonon-phonon scattering, anharmonic phonon renormalization, and heat transport beyond the phonon gas picture. Interatomic force constants (IFCs), however, as a shared pillar of the above concepts, are sometimes ambiguously implemented in this process, resulting in non-negligible uncertainties among different studies. Here, we revisit the ultralow κL of Tl3VSe4 and make a rigorous comparison of κL obtained from IFCs extracted by different approaches (flavors). We find that the fourth-order IFCs extracted with small-displacement data (0 K) are prone to yield significant phonon frequency shifting (phonon renormalization) and four-phonon scatterings, which lead to distinctively increased or decreased κL, respectively. Moreover, the different flavors of second-, third-, and fourth-order IFCs extracted with the same large-displacement data (temperature-dependent) also result in significantly disparate κL owing to the mixing of higher-order IFCs into the lower-order IFCs. Our work discloses the potential uncertainties of κL that arise from the choice of different flavors of IFCs and underscores the pressing need for more rigorous and robust approaches to extracting IFCs

3-Oxapentane-1,5-diyl dicarbamate

The complete mol­ecule of the title compound, C6H12N2O5, is generated by a rotation about a twofold axis. The conformation along the bond sequence linking the two amino groups is trans-trans-(+)gauche-trans-trans. In the crystal, N—H⋯O hydrogen bonds link the mol­ecules into a three-dimensional supra­molecular architecture

Typical Scales in the Spatial Distribution of QSOs

We present results of searching for the possible typical scales in the spatial distribution of QSOs. Our method is based on the second derivative of the two-point correlation function. This statistic is sensitive to the scale of the maximum in the spectrum $P(k)$ of the density perturbation in the universe. This maximum or bend scale can be detected as the wavelengths of the periodic component in the second derivative of the integral correlation function. For various QSO samples compiled from surveys of pencil-beam and bright QSOs, a typical scale of about 93 $\pm$ 10 h$^{-1}$Mpc for $q_0=0.5$ has been detected. This typical scale is in good agreement with that found in the spatial distributions of galaxies, clusters of galaxies, and CIV absorption systems of QSOs if $q_0$ is taken to be $\sim 0.2$. Therefore, it is likely a common or universal scale in the large scale structure traced by these objects. This result is consistent with the assumption that the typical scale comes from a characteristic scale in the spectrum of the density perturbation in the universe.Comment: 16 pages, 13 figures (available upon request), Latex, AZPH-TH/94-02, to appear in Ap.

Individual position diversity in dependence socioeconomic networks increases economic output

The availability of big data recorded from massively multiplayer online role-playing games (MMORPGs) allows us to gain a deeper understanding of the potential connection between individuals' network positions and their economic outputs. We use a statistical filtering method to construct dependence networks from weighted friendship networks of individuals. We investigate the 30 distinct motif positions in the 13 directed triadic motifs which represent microscopic dependences among individuals. Based on the structural similarity of motif positions, we further classify individuals into different groups. The node position diversity of individuals is found to be positively correlated with their economic outputs. We also find that the economic outputs of leaf nodes are significantly lower than that of the other nodes in the same motif. Our findings shed light on understanding the influence of network structure on economic activities and outputs in socioeconomic system.Comment: 19 pages, 5 figure

Effect of CYP2C9*3 gene polymorphism on lipid-lowering efficacy of fluvastatin in a Chinese hyperlipidemic population

Purpose: To investigate the frequency of gene CYP2C9*3 in Chinese populations, and to analyze the impact of CYP2C9*3 genetic polymorphism on the cholesterol-lowering effect of fluvastatin in a Chinese hyperlipidemic population.Methods: CYP2C9 genotype was determined by polymerase chain reaction - restriction fragment length polymorphism (PCR - RFLP) in 270 unrelated hyperlipidemic patients who were treated with 80mg fluvastatin monotherapy daily for 4 weeks and 250 healthy controls. Clinical data were collected prior to treatment with fluvastatin and 4 weeks after.Results: In 270 hyperlipidemic patients, the frequency of CYP2C9*3 was 3.70 % which is significantly higher than in 250 healthy controls (2.60 %) (p < 0.01). After oral intake of fluvastatin 80 mg daily for 4 weeks, CYP2C9*1/*3 genotype was associated with a decrease in LDL-C levels (by 33.9 % in CYP2C9*1/*3 versus 24.5 % for CYP2C9*1/*1, p < 0.05) and with reduction of TC (by 36.4 % in CYP2C9*1/*3 versus 19.4 % in CYP2C9*1/*1, p < 0.05).Conclusion: The frequency of CYP2C9*3 is 3.17 % in Chinese populations, and those who carry CYP2C9*3 mutation have a high risk of hyperlipidemia. CYP2C9*3 seems to increase the lipid-lowering effects of fluvastatin.Keywords: Hyperlipidemia, Gene, CYP2C9, Polymorphism, Polymerase chain reaction, Restriction fragment length polymorphism, Fluvastati