Semantic modelling of user interests based on cross-folksonomy analysis

The continued increase in Web usage, in particular participation in folksonomies, reveals a trend towards a more dynamic and interactive Web where individuals can organise and share resources. Tagging has emerged as the de-facto standard for the organisation of such resources, providing a versatile and reactive knowledge management mechanism that users find easy to use and understand. It is common nowadays for users to have multiple profiles in various folksonomies, thus distributing their tagging activities. In this paper, we present a method for the automatic consolidation of user profiles across two popular social networking sites, and subsequent semantic modelling of their interests utilising Wikipedia as a multi-domain model. We evaluate how much can be learned from such sites, and in which domains the knowledge acquired is focussed. Results show that far richer interest profiles can be generated for users when multiple tag-clouds are combine

Molecular mechanisms of microtubule-dependent kinetochore transport toward spindle poles

In mitosis, kinetochores are initially captured by the lateral sides of single microtubules and are subsequently transported toward spindle poles. Mechanisms for kinetochore transport are not yet known. We present two mechanisms involved in microtubule-dependent poleward kinetochore transport in Saccharomyces cerevisiae. First, kinetochores slide along the microtubule lateral surface, which is mainly and probably exclusively driven by Kar3, a kinesin-14 family member that localizes at kinetochores. Second, kinetochores are tethered at the microtubule distal ends and pulled poleward as microtubules shrink (end-on pulling). Kinetochore sliding is often converted to end-on pulling, enabling more processive transport, but the opposite conversion is rare. The establishment of end-on pulling is partly hindered by Kar3, and its progression requires the Dam1 complex. We suggest that the Dam1 complexes, which probably encircle a single microtubule, can convert microtubule depolymerization into the poleward kinetochore-pulling force. Thus, microtubule-dependent poleward kinetochore transport is ensured by at least two distinct mechanisms

Effect of Fermented Chub Mackerel Extract on Lipid Metabolism of Diabetic Rats

The present study was conducted to evaluate the effect of fermented chub mackerel extract(FCME) on lipid metabolism in diabetic rats. Four week-old male Wistar rats were divided into threegroups based on weight. All rats were induced with diabetes mellitus by single intraperitoneal injectionof streptozotocin at 45 mg/kg body weight. Thereafter, they were randomly distributed to threetreatments with 7 rats assigned to each treatment. One group was the control with no additive, and twotreatmentgroups were given the purified diets supplemented with 1% or 2% FCME. Experimentalresults showed that in comparison to the control, diabetic rats fed FCME increased feed intake (P<0.01)and body weight gain (P<0.05). FCME inclusion significantly reduced the activities of acetyl-CoAcarboxylase (P<0.01) and fatty acid synthetase (P<0.05) in diabetic rats. FCME significantly increasedcholesterol 7 -hydroxylase with no effect on HMG-CoA reductase activity. FCME had no effect onhepatic triglyceride, free cholesterol and phospholipid. FCME inclusion at 1% level significantlyreduced serum triglyceride. FCME significantly increased HDL-cholesterol (P<0.05) with no effect onLDL + VLDL-cholesterol, and significantly reduced atherogenic index. FCME did not significantlyaffect serum insulin and glucose concentration. In conclusion, FCME supplementation altered lipidmetabolism in diabetic rats. FCME supplementation reduced the risk of atherosclerosis in diabetic rats

SWAP, SWITCH, and STABILIZE:Mechanisms of Kinetochore–Microtubule Error Correction

For correct chromosome segregation in mitosis, eukaryotic cells must establish chromosome biorientation where sister kinetochores attach to microtubules extending from opposite spindle poles. To establish biorientation, any aberrant kinetochore–microtubule interactions must be resolved in the process called error correction. For resolution of the aberrant interactions in error correction, kinetochore–microtubule interactions must be exchanged until biorientation is formed (the SWAP process). At initiation of biorientation, the state of weak kinetochore–microtubule interactions should be converted to the state of stable interactions (the SWITCH process)—the conundrum of this conversion is called the initiation problem of biorientation. Once biorientation is established, tension is applied on kinetochore–microtubule interactions, which stabilizes the interactions (the STABILIZE process). Aurora B kinase plays central roles in promoting error correction, and Mps1 kinase and Stu2 microtubule polymerase also play important roles. In this article, we review mechanisms of error correction by considering the SWAP, SWITCH, and STABILIZE processes. We mainly focus on mechanisms found in budding yeast, where only one microtubule attaches to a single kinetochore at biorientation, making the error correction mechanisms relatively simpler

Upper Bound on the First Star Formation History

Our understanding of the nature of the extragalactic background light (EBL) has improved with the recent development of gamma-ray observation techniques. An open subject in the context of the EBL is the reionization epoch, which is an important probe of the formation history of first stars, the so-called Population III (Pop III) stars. Although the mechanisms for the formation of Pop III stars are rather well understood on theoretical grounds, their formation history is still veiled in mystery because of their faintness. To shed light into this matter, we study jointly the gamma-ray opacity of distant objects and the reionization constraints from studies of intergalactic gas. By combining these studies, we obtain a sensitive upper bound on the Pop III star formation rate density as $\dot\rho_{*}(z)<0.01[(1+z)/{(1+7.0)}]^{3.4}({f_{\rm esc}}/{0.2})^{-1}({C}/{3.0})\ {\rm M}_{\odot} {\rm yr}^{-1}\ {\rm Mpc}^{-3}$ at $z\ge7$, where $f_{\rm esc}$ and $C$ are the escape fraction of ionizing photons from galaxies and the clumping factor of the intergalactic hydrogen gas. This limit is a $\sim10$ times tighter constraint compared with previous studies that take into account gamma-ray opacity constraints only. Even if we do not include the current gamma-ray constraints, the results do not change. This is because the detected gamma-ray sources are still at $z\le4.35$ where the reionization has already finished.Comment: 5 pages, 2 figures, accepted for publication in ApJ

Different Methods of Forming Cold Fronts in Non-Merging Clusters

Sharp edges in X-ray surface brightness with continuous gas pressure called cold fronts have been often found in relaxed galaxy clusters such as Abell 496. Models that explain cold fronts as surviving cores of head-on subcluster mergers do not work well for these clusters and competing models involving gas sloshing have been recently proposed. Here, we test some concrete predictions of these models in a combined analysis of density, temperature, metal abundances and abundance ratios in a deep Chandra exposure of Abell 496. We confirm that the chemical discontinuities found in this cluster are not consistent with a core merger remnant scenario. However, we find chemical gradients across a spiral "arm" discovered at 73 kpc north of the cluster center and coincident with the sharp edge of the main cold front in the cluster. Despite the overall SN Ia iron mass fraction dominance found within the cooling radius of this cluster, the metal enrichment along the arm, determined from silicon and iron abundances, is consistent with a lower SN Ia iron mass fraction (51% +- 14%) than that measured in the surrounding regions (85% +- 14%). The "arm" is also significantly colder than the surroundings by 0.5-1.6 keV. The arm extends from a boxy colder region surrounding the center of the cluster, where two other cold fronts are found. This cold arm is a prediction of current high resolution numerical simulations as a result of an off-center encounter with a less massive pure dark matter halo and we suggest that the cold fronts in A496 provide the first clear corroboration of such model, where the closest encounter happened ~ 0.5 Gyr ago. We also argue for a possible candidate dark matter halo responsible for the cold fronts in the outskirts of A496.Comment: 11 ApJ pages, 1 Table, 16 Figures, accepted for publication in the Astrophysical Journal. For full version with all hi-res figures click on http://www.astro.lsa.umich.edu/~rdupke/a496sub.pd

Effect of zero energy bound states on macroscopic quantum tunneling in high-Tc superconductor junctions

The macroscopic quantum tunneling (MQT) in the current biased high-Tc superconductor Josephson junctions and the effect of the zero energy bound states (ZES) on the MQT are theoretically investigated. We obtained the analytical formula of the MQT rate and showed that the presence of the ZES at the normal/superconductor interface leads to a strong Ohmic quasiparticle dissipation. Therefore, the MQT rate is noticeably inhibited in compared with the c-axis junctions in which the ZES are completely absent.Comment: 4 pages, 1 figure, comment and reference about recent experiment adde