Home About us Contact
|
Home About us Contact | ||
|
|
||
Basic Building Block (basic + building_block)
Selected AbstractsOff-shell supergravity in five dimensions and supersymmetric brane world scenariosFORTSCHRITTE DER PHYSIK/PROGRESS OF PHYSICS, Issue 9 2003M. ZuckerArticle first published online: 18 AUG 200 We review the construction of off-shell Poincaré supergravity in five dimensions. We describe in detail the minimal multiplet, which is the basic building block, containing the propagating fields of supergravity. All matter multiplets containing (8 + 8) components, being the smallest matter multiplets in five dimensions, are constructed. Using these multiplets the complete tensor calculus for supergravity is developed. As expected it turns out, that there exist three distinct minimal (i.e. containing (48 + 48) field components) off-shell supergravities. The lagrangians for these theories and their gauged variants are given explicitly. These results are used in the second part to develop a tensor calculus on the orbifold . Gauged supergravity on the orbifold with additional cosmological constants at the fixpoints, is constructed. This generalizes the work of Randall-Sundrum to local supersymmetry. The developed tensor calculus is used to extend this model to include matter located at the fixpoints. Chiral and super Yang-Mills multiplets at the fixpoints are considered. [source] Combined seismic tomographic and ultrashallow seismic reflection study of an Early Dynastic mastaba, Saqqara, EgyptARCHAEOLOGICAL PROSPECTION, Issue 4 2005Mohamed Metwaly Abstract Mastabas were large rectangular structures built for the funerals and burials of the earliest Pharaohs. One such mastaba was the basic building block that led to the first known stone pyramid, the,>4600-year old Step Pyramid within the Saqqara necropolis of Egypt. We have tested a number of shallow geophysical techniques for investigating in a non-invasive manner the subsurface beneath a large Early Dynastic mastaba located close to the Step Pyramid. After discovering that near-surface sedimentary rocks with unusually high electrical conductivities precluded the use of the ground-penetrating radar method, a very high-resolution seismic data set was collected along a profile that extended the 42.5,m length of the mastaba. A sledgehammer source was used every 0.2,m and the data were recorded using a 48-channel array of single geophones spaced at 0.2,m intervals. Inversions of the direct- and refracted-wave travel times provided P-wave velocity tomograms of the shallow subsurface, whereas relatively standard processing techniques yielded a high-fold (50,80) ultrashallow seismic reflection section. The tomographic and reflection images were jointly interpreted in terms of loose sand and friable limestone layers with low P-wave velocities of 150,650,m,s,1 overlying consolidated limestone and shale with velocities,>,1500,m,s,1. The sharp contact between the low- and high-velocity regimes was approximately horizontal at a depth of ca. 2,m. This contact was the source of a strong seismic reflection. Above this contact, the velocity tomogram revealed moderately high velocities at the surface location of a friable limestone outcrop and two low-velocity blocks that probably outlined sand-filled shafts. Below the contact, three regularly spaced low velocity blocks probably represented tunnels and/or subsurface chambers. Copyright © 2005 John Wiley & Sons, Ltd. [source] Crystallization and preliminary X-ray diffraction analysis of mouse galectin-4 N-terminal carbohydrate recognition domain in complex with lactoseACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 7 2008Veronika Krej, íková Galectin-4 is thought to play a role in the process of tumour conversion of cells of the alimentary tract and the breast tissue; however, its exact function remains unknown. With the aim of elucidating the structural basis of mouse galectin-4 (mGal-4) binding specificity, we have undertaken X-ray analysis of the N-terminal domain, CRD1, of mGal-4 in complex with lactose (the basic building block of known galectin-4 carbohydrate ligands). Crystals of CRD1 in complex with lactose were obtained using vapour-diffusion techniques. The crystals belong to tetragonal space group P4212 with unit-cell parameters a = 91.1, b = 91.16, c = 57.10,Ĺ and preliminary X-ray diffraction data were collected to 3.2,Ĺ resolution. An optimized crystallization procedure and cryocooling protocol allowed us to extend resolution to 2.1,Ĺ. Structure refinement is currently under way; the initial electron-density maps clearly show non-protein electron density in the vicinity of the carbohydrate binding site, indicating the presence of one lactose molecule. The structure will help to improve understanding of the binding specificity and function of the potential colon cancer marker galectin-4. [source] Bulk Nanostructured Materials: Non-Mechanical Synthesis,ADVANCED ENGINEERING MATERIALS, Issue 8 2010Yulia Ivanisenko An overview of the synthesis and processing techniques for bulk nanostructured materials that are based on "bottom-up" approaches is presented. Typically, these processes use nanoparticles, which can be produced by a variety of methods in the gas, liquid or solid state, as the basic building blocks. Their assembly into bulk nanostructured materials requires at least one more processing step, such as compaction or the formation of thick films. For certain nanostructures, film deposition techniques can also be employed. A wide range of nanostructures , from thick films with theoretical density to bulk nanocrystalline materials with nanoporosity , exhibiting novel structural and functional properties useful in many fields of applications are presented. Additionally, the properties of these bulk nanostructured materials can be categorized as either tailored, i.e., microstructure-dependent and inherently irreversible, or tunable, i.e., reversible by the application of an external field. Examples of both categories of properties are presented and the special role of the synthesis and processing routes to achieve the necessary nanostructures is emphasized. [source] KERIS: evolving software with extensible modulesJOURNAL OF SOFTWARE MAINTENANCE AND EVOLUTION: RESEARCH AND PRACTICE, Issue 5 2005Matthias ZengerArticle first published online: 26 SEP 200 Abstract We present the programming language KERIS, an extension of Java with explicit support for software evolution. KERIS introduces extensible modules as the basic building blocks for software. Modules are composed hierarchically, explicitly revealing the architecture of systems. A distinct feature of the module design is that modules do not get linked manually. Instead, the wiring of modules gets inferred. The module assembly and refinement mechanism of KERIS is not restricted to the unanticipated extensibility of atomic modules. It also allows extensions of already linked systems by replacing selected submodules with compatible versions without needing to re-link the full system. Extensibility is type-safe and non-invasive, i.e., the extension of a module preserves the original version and does not require access to source code. Copyright © 2005 John Wiley & Sons, Ltd. [source] The dual role of a loop with low loop contact distance in folding and domain swappingPROTEIN SCIENCE, Issue 7 2002Apichart Linhananta Abstract , helices, , strands, and loops are the basic building blocks of protein structure. The folding kinetics of , helices and , strands have been investigated extensively. However, little is known about the formation of loops. Experimental studies show that for some proteins, the formation of a single loop is the rate-determining step for folding, whereas for others, a loop (or turn) can misfold to serve as the hinge loop region for domain-swapped species. Computer simulations of an all-atom model of fragment B of Staphylococcal protein A found that the formation of a single loop initiates the dominant folding pathway. On the other hand, the stability analysis of intermediates suggests that the same loop is a likely candidate to serve as a hinge loop for domain swapping. To interpret the simulation result, we developed a simple structural parameter: the loop contact distance (LCD), or the sequence distance of contacting residues between a loop and the rest of the protein. The parameter is applied to a number of other proteins, including SH3 domains and prion protein. The results suggest that a locally interacting loop (low LCD) can either promote folding or serve as the hinge region for domain swapping. Thus, there is an intimate connection between folding and domain swapping, a possible cause of misfolding and aggregation. [source] | ||||||||||