Central extensions of mapping class groups from characteristic classes

Tangential structures on smooth manifolds, and the extension of mapping class groups they induce, admit a natural formulation in terms of higher (stacky) differential geometry. This is the literal translation of a classical construction in differential topology to a sophisticated language, but it has the advantage of emphasizing how the whole construction naturally emerges from the basic idea of working in slice categories. We characterize, for every higher smooth stack equipped with tangential structure, the induced higher group extension of the geometric realization of its higher automor- phism stack. We show that when restricted to smooth manifolds equipped with higher degree topological structures, this produces higher extensions of homotopy types of diffeomorphism groups. Passing to the groups of connected components, we obtain abelian extensions of mapping class groups and we derive sufficient conditions for these being central. We show as a special case that this provides an elegant re-construction of Segal’s approach to $\mathbb{Z}$ -extensions of mapping class groups of surfaces that provides the anomaly cancellation of the modular functor in Chern-Simons theory. Our construction generalizes Segal’s approach to higher central extensions of mapping class groups of higher dimensional manifolds with higher tangential structures, expected to provide the analogous anomaly cancellation for higher dimensional TQFTs

Perbandingan Pemberian Heparin Subkutan Dan Intravena Terhadap Kadar Fibrinogen Pada Pencegahan Deep Vein Thrombosis

Background: Deep vein thrombosis (DVT) is a condition where thrombus is formed in a deep vein especially in the lower limbs and inguinal. Blood clots can obstruct blood flow from lower limbs to the heart. DVT is an often occured disease and can be fatal and deathly if it is not get diagnosed and treated effectively. Giving anticoagulants such as heparin either intravenously or subcunaneosly can prevent thrombus formation. Fibrinogen levels is directly proportional to the risk of a thrombus generation.Methods: An observational study with cross-sectional approach. Data were derived from secondary data with total sample of 20 which divided into two groups. Group 1 was an ICU patient who given intravenous heparin and Group 2 given subcutaneous heparin. Fibrinogen levels were recorded and compared before and after one day heparin administration.Results: There is no significant differences (p=0,226) between fibrinogen levels before and after intravenous heparin administration (388,56209,31 mg/dl vs 468,93178,38 mg/dl). In subcutaneous heparin group there is a significant (p=0,006) increase in levels of fibrinogen before and after heparin administration (265,2790,67 mg/dl vs 453,93112,49 mg/dl). After comparing pre-post fibrinogen levels in both groups (60,37228,85 mg/dl vs 188,66169,19 mg/dl), we obtained no significant difference between two groups (p=0,171).Conclusions: No significant differences between administering heparin intravenously and subcutaneously against fibrinogen levels as a prophylactic of deep vein thrombosis in ICU

The Face Semigroup Algebra of a Hyperplane Arrangement

This article presents a study of an algebra spanned by the faces of a hyperplane arrangement. The quiver with relations of the algebra is computed and the algebra is shown to be a Koszul algebra. It is shown that the algebra depends only on the intersection lattice of the hyperplane arrangement. A complete system of primitive orthogonal idempotents for the algebra is constructed and other algebraic structure is determined including: a description of the projective indecomposable modules; the Cartan invariants; projective resolutions of the simple modules; the Hochschild homology and cohomology; and the Koszul dual algebra. A new cohomology construction on posets is introduced and it is shown that the face semigroup algebra is isomorphic to the cohomology algebra when this construction is applied to the intersection lattice of the hyperplane arrangement.Comment: 37 pages, LaTeX; Added section 8.3B; Changed the wording of a few paragraphs in the introduction and abstract. No major change

Batako Berlubang Geopolimer Berbahan Dasar Lumpur Sidoarjo

Lumpur Sidoarjo merupakan material yang sedang dikembangkan sebagai pengganti semen. Alasan digunakannya lumpur Sidoarjo adalah jumlahnya yang melimpah dan telah terbukti memiliki kandungan yang dapat menggantikan fungsi semen. Oleh karena itu sebaiknya lumpur Sidoarjo dijadikan sebagai produk jadi yang berguna, untuk masyarakat secara luas. Salah satu produk yang cocok diproduksi dari lumpur Sidoarjo adalah batako geopolimer. Batako geopolimer sendiri mempunyai beberapa kelebihan daripada batako pada umumnya, antara lain dapat mengurangi pelepasan gas CO2 ke atmosfer karena tidak menggunakan semen, sehingga lebih ramah terhadap lingkungan, selain itu bahan geopolimer memiliki ketahanan serangan dari luar. Untuk mengolah lumpur agar siap pakai dalam pembuatan batako, lumpur harus melewati beberapa tahapan, antara lain lumpur harus dijemur selama 24 jam, kemudian dimasukkan ke oven selama 24 jam. Setelah itu lumpur dibakar dengan suhu 650ºC selama 9 jam agar sifat lumpur menjadi amorf sehingga dapat digunakan. Lumpur kemudian digiling sampai melewati ayakan nomor 200. Setelah siap dipakai, lumpur dicampurkan dengan pasir, NaOH, serta sodium silikat dengan perbandingan tertentu untuk dijadikan campuran mortar untuk pembuatan batako. Dari hasil penelitian yang telah dilakukan, kuat tekan dan penyerapan air dari mortar menunjukkan hasil yang baik, Sehingga produk batako geopolimer memenuhi syarat batako pada umumnya

T-duality and Differential K-Theory

We give a precise formulation of T-duality for Ramond-Ramond fields. This gives a canonical isomorphism between the "geometrically invariant" subgroups of the twisted differential K-theory of certain principal torus bundles. Our result combines topological T-duality with the Buscher rules found in physics.Comment: 23 pages, typos corrected, submitted to Comm.Math.Phy

Measurements of the effect of collisions on transverse beam halo diffusion in the Tevatron and in the LHC

Beam-beam forces and collision optics can strongly affect beam lifetime, dynamic aperture, and halo formation in particle colliders. Extensive analytical and numerical simulations are carried out in the design and operational stage of a machine to quantify these effects, but experimental data is scarce. The technique of small-step collimator scans was applied to the Fermilab Tevatron collider and to the CERN Large Hadron Collider to study the effect of collisions on transverse beam halo dynamics. We describe the technique and present a summary of the first results on the dependence of the halo diffusion coefficient on betatron amplitude in the Tevatron and in the LHC.Comment: 4 pages, 2 figures. Submitted to the Proceedings of the ICFA Mini-Workshop on Beam-beam Effects in Hadron Colliders (BB2013), Geneva, Switzerland, 18-22 March 201

Fastener starter tool

A fastener starter tool includes a number of spring retention fingers for retaining a small part, or combination of parts. The tool has an inner housing, which holds the spring retention fingers, a hand grip, and an outer housing configured to slide over the inner housing and the spring retention fingers toward and away from the hand grip, exposing and opening, or respectively, covering and closing, the spring retention fingers. By sliding the outer housing toward (away from) the hand grip, a part can be released from (retained by) the tool. The tool may include replaceable inserts, for retaining parts, such as screws, and configured to limit the torque applied to the part, to prevent cross threading. The inner housing has means to transfer torque from the hand grip to the insert. The tool may include replaceable bits, the inner housing having means for transferring torque to the replaceable bit

Beam halo dynamics and control with hollow electron beams

Experimental measurements of beam halo diffusion dynamics with collimator scans are reviewed. The concept of halo control with a hollow electron beam collimator, its demonstration at the Tevatron, and its possible applications at the LHC are discussed.Comment: 5 pages, 4 figures, in Proceedings of the 52nd ICFA Advanced Beam Dynamics Workshop on High-Intensity and High-Brightness Hadron Beams (HB2012), Beijing, China, 17-21 September 201

Design of a low band gap oxide ferroelectric: Bi6_6Ti4_4O17_{17}

A strategy for obtaining low band gap oxide ferroelectrics based on charge imbalance is described and illustrated by first principles studies of the hypothetical compound Bi$_6$Ti$_4$O$_{17}$, which is an alternate stacking of the ferroelectric Bi$_4$Ti$_3$O$_{12}$. We find that this compound is ferroelectric, similar to Bi$_4$Ti$_3$O$_{12}$ although with a reduced polarization. Importantly, calculations of the electronic structure with the recently developed functional of Tran and Blaha yield a much reduced band gap of 1.83 eV for this material compared to Bi$_4$Ti$_3$O$_{12}$. Therefore, Bi$_6$Ti$_4$O$_{17}$ is predicted to be a low band gap ferroelectric material

Indexing Dan Searching Document Menggunakan Metode Semantic Suffix Tree Clustering Berbasis Android

Anroid smartphone device has been involved in user's way of living in this modern era. Smartphone device is used in user's daily activity such as reading and storing electronic document in Pdf, Word and other file formats. User might and frequently forgot elctronic document's directory in the smartphone.This research aims to help user to find documents that reflect user's keyword semantically or literally. Documents that reflect user keyword semantically or literaly will be shown. Various method is tested to minimize time use in clustering using suffix tree to semantic searching processes.This research finds that user could find documents in the smartphone that reflect user's keyword. Average time use for clustering about 100 documents containing 1000 word for each document is 686.7 seconds. User is able to search for document right after clustering process is done. Average time use for document searching is less than 2 seconds. Hence, thread implementation for processes decrease time consume greatly and the search result displayed to the user represents document content semantically