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Different Layers (different + layer)
Selected AbstractsRaycasting of Light Field Galleries from Volumetric DataCOMPUTER GRAPHICS FORUM, Issue 3 2008C. Rezk-Salama Abstract The paper describes a technique to generate high-quality light field representations from volumetric data. We show how light field galleries can be created to give unexperienced audiences access to interactive high-quality volume renditions. The proposed light field representation is lightweight with respect to storage and bandwidth capacity and is thus ideal as exchange format for visualization results, especially for web galleries. The approach expands an existing sphere-hemisphere parameterization for the light field with per-pixel depth. High-quality paraboloid maps from volumetric data are generated using GPU-based ray-casting or slicing approaches. Different layers, such as isosurfaces, but not restricted to, can be generated independently and composited in real time. This allows the user to interactively explore the model and to change visibility parameters at run-time. [source] Diversity of phototrophic bacteria in microbial mats from Arctic hot springs (Greenland)ENVIRONMENTAL MICROBIOLOGY, Issue 1 2007Guus Roeselers Summary We investigated the genotypic diversity of oxygenic and anoxygenic phototrophic microorganisms in microbial mat samples collected from three hot spring localities on the east coast of Greenland. These hot springs harbour unique Arctic microbial ecosystems that have never been studied in detail before. Specific oligonucleotide primers for cyanobacteria, purple sulfur bacteria, green sulfur bacteria and Choroflexus/Roseiflexus -like green non-sulfur bacteria were used for the selective amplification of 16S rRNA gene fragments. Amplification products were separated by denaturing gradient gel electrophoresis (DGGE) and sequenced. In addition, several cyanobacteria were isolated from the mat samples, and classified morphologically and by 16S rRNA-based methods. The cyanobacterial 16S rRNA sequences obtained from DGGE represented a diverse, polyphyletic collection of cyanobacteria. The microbial mat communities were dominated by heterocystous and non-heterocystous filamentous cyanobacteria. Our results indicate that the cyanobacterial community composition in the samples were different for each sampling site. Different layers of the same heterogeneous mat often contained distinct and different communities of cyanobacteria. We observed a relationship between the cyanobacterial community composition and the in situ temperatures of different mat parts. The Greenland mats exhibited a low diversity of anoxygenic phototrophs as compared with other hot spring mats which is possibly related to the photochemical conditions within the mats resulting from the Arctic light regime. [source] Microsite-dependent changes in methanogenic populations in a boreal oligotrophic fenENVIRONMENTAL MICROBIOLOGY, Issue 11 2003Pierre E. Galand Summary Wetlands, including peatlands, are the main source of natural methane emission. Well-defined fen microsites have different methane emissions rates, but it is not known whether the methane-producing Archaea communities vary at these sites. Possible horizontal variations of communities, in a natural oligotrophic fen, were analysed by characterizing the methanogens from two well-defined microsites: Eriophorum lawn and Hummock. Community structures were studied at two different layers of the fen, showing, respectively, high and low methane production. The structure of methanogen populations was determined using molecular techniques targeting the 16SrRNA gene and combined denaturing gradient gel electrophoresis (DGGE) and restriction fragment length polymorphism (RFLP) analysis. Results subjected to non-metric multidimensional scaling (MDS), diversity indices calculation and phylogenetic analysis revealed that upper layer communities changed with site while deeper layer communities remained the same. Phylogenetic analyses revealed six different clusters of sequences grouping with only two known orders of methanogens. Upper layers of Hummock were dominated by sequences clustering with members of Methanomicrobiales and sequences dominating the upper part of the Eriophorum lawn were related to members of the order Methanosarcinales. Novel methanogenic sequences were found at both sites at both depths. Vegetation characterizing the microsites probably influences the microbial communities in the layers of the fen where methane is produced. [source] Quantitative analysis of postnatal neurogenesis and neuron number in the macaque monkey dentate gyrusEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 2 2010Adeline Jabès Abstract The dentate gyrus is one of only two regions of the mammalian brain where substantial neurogenesis occurs postnatally. However, detailed quantitative information about the postnatal structural maturation of the primate dentate gyrus is meager. We performed design-based, stereological studies of neuron number and size, and volume of the dentate gyrus layers in rhesus macaque monkeys (Macaca mulatta) of different postnatal ages. We found that about 40% of the total number of granule cells observed in mature 5,10-year-old macaque monkeys are added to the granule cell layer postnatally; 25% of these neurons are added within the first three postnatal months. Accordingly, cell proliferation and neurogenesis within the dentate gyrus peak within the first 3 months after birth and remain at an intermediate level between 3 months and at least 1 year of age. Although granule cell bodies undergo their largest increase in size during the first year of life, cell size and the volume of the three layers of the dentate gyrus (i.e. the molecular, granule cell and polymorphic layers) continue to increase beyond 1 year of age. Moreover, the different layers of the dentate gyrus exhibit distinct volumetric changes during postnatal development. Finally, we observe significant levels of cell proliferation, neurogenesis and cell death in the context of an overall stable number of granule cells in mature 5,10-year-old monkeys. These data identify an extended developmental period during which neurogenesis might be modulated to significantly impact the structure and function of the dentate gyrus in adulthood. [source] Comparative distribution of the mammalian mediator subunit thyroid hormone receptor-associated protein (TRAP220) mRNA in developing and adult rodent brainEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 4 2002Anastasia Galeeva Abstract TRAP220 (thyroid hormone receptor-associated protein) is a recently cloned nuclear receptor coactivator, which interacts with several nuclear receptors in a ligand-dependent manner and stimulates transcription by recruiting the TRAP mediator complex to hormone responsive promoter regions. TRAP220 has been shown to interact with thyroid hormone receptors, vitamin D receptors, peroxisome proliferator-activated receptors, retinoic acid receptors and oestrogen receptors. Thyroid hormone and retinoic acid play very important roles in brain development and they also influence adult brain. Using in situ hybridization we have examined expression of TRAP220 mRNA in the central nervous system during development and in adult rat and mouse brain. Expression of TRAP220 was seen already during early embryonic development in the epithelium of neural tube at E9 in mouse and at E12 in rat. At later stages of development the strongest signal was seen in different layers of cerebral neocortex, external germinal layer of cerebellum, differentiating fields of hippocampus and neuroepithelium, and a moderate signal was detected in basal ganglia, different areas of diencephalon and midbrain. In adult rat brain the signal was more restricted than during development. TRAP220 expression occurred mostly in the granular layer of cerebellar cortex, piriform cortex and hippocampal formation. The signal was found predominantly in neurons. Our work supports the assumption that TRAP220 plays an important role in growth and differentiation of central nervous system and may have a function in certain areas of adult brain. [source] Expression pattern of somatostatin receptor subtypes 1,5 in human skin: an immunohistochemical study of healthy subjects and patients with psoriasis or atopic dermatitisEXPERIMENTAL DERMATOLOGY, Issue 12 2006Lena Hagströmer Abstract:, In psoriasis and atopic dermatitis, the inflammatory events have neurogenic components and the neuropeptides modify the functions of immuno-active cells in the skin. Somatostatin is a neuropeptide with several neuroendocrine and immunomodulating properties and mediates its actions by five distinct subtypes of G-protein-coupled receptors (SSTR1-5). This study describes the distribution of SSTR1,5, analysed with immunohistochemistry, in psoriasis, atopic dermatitis and controls. Normal human skin and lesional skin from patients with psoriasis or atopic dermatitis showed many similarities, but also some differences, as regards SSTR expression. SSTR1,3 were strongly expressed in the epidermis of healthy skin, and in the skin of patients with psoriasis or atopic dermatitis. It is noteworthy that SSTR4 and 5 were strongly expressed in the epidermis of psoriasis patients, but weakly expressed in the epidermis of those with atopic dermatitis and normal skin. The intensity of the staining also varied considerably between the different layers of the epidermis, especially in psoriasis patients. In all cases, the dendritic cells, found mostly in the papillary and upper reticular dermis, showed a strong expression of SSTR1,4, but a weak expression of SSTR5. SSTR1,5 were strongly expressed in the sweat glands in all skin biopsies. Hair follicles and sebaceous glands expressed all five subtypes. Striated muscle fibres showed an intense positive expression of SSTR1,4, but a weak or negative expression of SSTR5. The wide distribution and expression pattern of all five SSTRs in human skin suggest that somatostatin is involved in the interactions between the nervous system and the skin. [source] Matters of the heart: the physiology of cardiac function and failureEXPERIMENTAL PHYSIOLOGY, Issue 6 2007Godfrey Smith Heart failure as a result of a myocardial infarction (MI) is a common condition with a poor prognosis. The adaptive changes in the surviving myocardium appear to be insufficient in terms of both mechanical/contractile performance and electrical stability. The modification of the underlying myocardial physiology is complex, varying across the different layers within the wall of the ventricle and within one layer. Two therapeutic strategies are briefly discussed, as outlined here. (i) Enhancing contractility by alteration of the expression of a single protein (e.g. sarco-endoplasmic reticulum Ca2+ ATPase, SERCA) could potentially reverse both mechanical and electrical abnormalities. However, experimental data involving the upregulation of SERCA suggest that the therapeutic range of this approach is narrow. (ii) The use of regular exercise training to improve cardiac performance in heart failure. This appears to act by normalizing a number of aspects of myocardial physiology. [source] High vertical and low horizontal diversity of Prochlorococcus ecotypes in the Mediterranean Sea in summerFEMS MICROBIOLOGY ECOLOGY, Issue 2 2007Laurence Garczarek Abstract Natural populations of the marine cyanobacterium Prochlorococcus exist as two main ecotypes, inhabiting different layers of the ocean's photic zone. These so-called high light- (HL-) and low light (LL-) adapted ecotypes are both physiologically and genetically distinct. HL strains can be separated into two major clades (HLI and HLII), whereas LL strains are more diverse. Here, we used several molecular techniques to study the genetic diversity of natural Prochlorococcus populations during the Prosope cruise in the Mediterranean Sea in the summer of 1999. Using a dot blot hybridization technique, we found that HLI was the dominant HL group and was confined to the upper mixed layer. In contrast, LL ecotypes were only found below the thermocline. Secondly, a restriction fragment length polymorphism analysis of PCR-amplified pcb genes (encoding the major light-harvesting proteins of Prochlorococcus) suggested that there were at least four genetically different ecotypes, occupying distinct but overlapping light niches in the photic zone. At comparable depths, similar banding patterns were observed throughout the sampled area, suggesting a horizontal homogenization of ecotypes. Nevertheless, environmental pcb gene sequences retrieved from different depths at two stations proved all different at the nucleotide level, suggesting a large genetic microdiversity within those ecotypes. [source] Polymer Field-Effect Transistors Fabricated by the Sequential Gravure Printing of Polythiophene, Two Insulator Layers, and a Metal Ink GateADVANCED FUNCTIONAL MATERIALS, Issue 2 2010Monika M. Voigt Abstract The mass production technique of gravure contact printing is used to fabricate state-of-the art polymer field-effect transistors (FETs). Using plastic substrates with prepatterned indium tin oxide source and drain contacts as required for display applications, four different layers are sequentially gravure-printed: the semiconductor poly(3-hexylthiophene-2,5-diyl) (P3HT), two insulator layers, and an Ag gate. A crosslinkable insulator and an Ag ink are developed which are both printable and highly robust. Printing in ambient and using this bottom-contact/top-gate geometry, an on/off ratio of >104 and a mobility of 0.04,cm2 V,1 s,1 are achieved. This rivals the best top-gate polymer FETs fabricated with these materials. Printing using low concentration, low viscosity ink formulations, and different P3HT molecular weights is demonstrated. The printing speed of 40,m min,1 on a flexible polymer substrate demonstrates that very high-volume, reel-to-reel production of organic electronic devices is possible. [source] Stratigraphy and formation processes of the Upper Pleistocene deposit at Gruta da Oliveira, Almonda karstic system, Torres Novas, PortugalGEOARCHAEOLOGY: AN INTERNATIONAL JOURNAL, Issue 3 2009Diego E. Angelucci Gruta da Oliveira is a cave located in the Almonda karstic system in central Portugal. Its Upper Pleistocene fill is made up of gravitational sediments with varied biogenic and anthropogenic inputs. The archaeological sequence (35,70 ka) is fairly homogeneous, reflecting a predominantly moist climatic context modulated by millennial-scale variations. Human occupation was almost continuous throughout. In the richer archaeological layers (8,14), the anthropogenic components are in primary position, and post-depositional processes are restricted, although penecontemporaneous biological activity,such as hyena scavenging,overprinted the record. In layers 15,19, the excavated area corresponds to the footslope of a talus, where accumulation proceeded mainly through runoff and where the lithics and bones derive from occupations situated ca. 5m outward. The base of the deposit is >2m from the current base of the excavation, suggesting that Oxygen Isotope Stage (OIS)-4 and OIS-5 sediments underlay the deposit already exposed. This study confirms the archaeological integrity of the Mousterian assemblages found in the different layers, and, given the dates for layer 8, supports the hypothesis that Neanderthals survived in western Iberia until at least 35,000,38,000 calendar years ago. © 2009 Wiley Periodicals, Inc. [source] On strike-slip faulting in layered mediaGEOPHYSICAL JOURNAL INTERNATIONAL, Issue 3 2002Maurizio Bonafede Summary We study the effects of structural inhomogeneities on the stress and displacement fields induced by strike-slip faults in layered media. An elastic medium is considered, made up of an upper layer bounded by a free surface and welded to a lower half-space characterized by different elastic parameters. Shear cracks with assigned stress drop are employed as mathematical models of strike-slip faults, which are assumed to be vertical and planar. If the crack is entirely embedded within the lower medium (case A), a Cauchy-kernel integral equation is obtained, which is solved by employing an expansion of the dislocation density in Chebyshev polynomials. If the crack is within the lower medium but it terminates at the interface (case B), a generalized Cauchy singularity appears in the integral kernel. This singularity affects the singular behaviour of the dislocation density at the crack tip touching the interface. Finally, the case of a crack crossing the interface is considered (case C). The crack is split into two interacting sections, each placed in a homogeneous medium and both open at the interface. Two coupled generalized Cauchy equations are obtained and solved for the dislocation density distribution of each crack section. An asymptotic study near the intersection between the crack and the interface shows that the dislocation densities for each crack section are bounded at the interface, where a jump discontinuity is present. As a corollary, the stress drop must be discontinuous at the interface, with a jump proportional to the rigidity contrast between the adjoining media. This finding is shown to have important implications for the development of geometrical complexities within transform fault zones: planar strike-slip faults cutting across layer discontinuities with arbitrary stress drop values are shown to be admissible only if the interface between different layers becomes unwelded during the earthquake at the crack/interface junction. Planar strike-slip faulting may take place only in mature transform zones, where a repetitive earthquake cycle has already developed, if the rheology is perfectly elastic. Otherwise, the fault cannot be planar: we infer that strike-slip faulting at depth is plausibly accompanied by en-echelon surface breaks in a shallow sedimentary layer (where the stress drop is lower than prescribed by the discontinuity condition), while ductile deformation (or steady sliding) at depth may be accommodated by multiple fault branching or by antithetic faulting in the upper brittle layer (endowed with lower rigidity but higher stress). [source] Neurotoxins in the Neurobiology of PainHEADACHE, Issue 2003Stephen D. Silberstein MD Migraine is a common, chronic, incapacitating, neurovascular disorder that affects an estimated 12% of the population. Understanding the basic mechanisms of pain is important when treating patients with chronic pain disorders. Pain, an unpleasant sensory and emotional experience, is usually triggered by stimulation of peripheral nerves and often associated with actual or potential tissue damage. Peripheral nerve fibers transmit pain signals from the periphery toward the spinal cord or brain stem. The different diameter pain fibers (A and C) vary in the speed of conduction and the type of pain transmitted (eg, sharp versus dull). When stimulated, peripheral pain fibers carrying sensory input from the body enter at different layers of the dorsal horn, which is then propagated toward the thalamus via the spinothalamic tract within the spinal cord. Conversely, sensory input from the face does not enter the spinal cord but enters the brain stem via the trigeminal nerve. This review describes in detail the neurobiological mechanisms and pathways for pain sensation, with a focus on migraine pain. [source] FROM IDEAS TO CONCEPTS TO METAPHORS: THE GERMAN TRADITION OF INTELLECTUAL HISTORY AND THE COMPLEX FABRIC OF LANGUAGEHISTORY AND THEORY, Issue 2 2010ELÍAS JOSÉ PALTI ABSTRACT Recently, the diffusion of the so-called "new intellectual history" led to the dismissal of the old school of the "history of ideas" on the basis of its ahistorical nature (the view of ideas as eternal entities). This formulation is actually misleading, missing the core of the transformation produced in the field. It is not true that the history of ideas simply ignored the fact that the meaning of ideas changes over time. The issue at stake here is really not how ideas changed (the mere description of the semantic transformation they underwent historically), but rather why they do. The study of the German tradition of intellectual history serves in this essay as a basis to illustrate the meaning and significance of the recent turn from ideas as its object. In the process of trying to account for the source of contingency of conceptual formations, it will open our horizon to the complex nature of the ways by which we invest the world with meaning. That is, it will disclose the presence of different layers of symbolic reality lying beneath the surface level of "ideas," and analyze their differential nature and functions. It will also show the reasons for the ultimate failure of the "history of ideas" approach, why discourses can never achieve their vocation to constitute themselves as self-enclosed, rationally integrated systems, thereby expelling contingency from their realm. In sum, it will show why historicity is not merely something that comes to intellectual history from without (as a by-product of social history or as the result of the action of an external agent), as the history of ideas assumed, but is a constitutive dimension of it. [source] A new Cosserat-like constitutive model for bedded salt rocksINTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS, Issue 15 2009Yin-Ping Li Abstract Salt rocks are commonly used as geologic host rocks for storage of gas and crude oil, and are being considered for the disposal of radioactive waste. Different from the salt rock domes in many countries, the salt rock formations in China are usually laminar with many alternating layers, i.e. rock salt, anhydrite, and/or mudstone. Considering the unique stratigraphic characteristics of these salt rocks, a new Cosserat-like medium constitutive model is proposed in order to facilitate efficient modeling of the mechanical behavior of these formations. In this model, a new representative volume element, containing two different layers, is employed to simulate the compatibility of the meso-displacement between two different layers and also the bending effect. A new method for the deformation and failure analysis of bedded salt rocks is derived therefrom. Having the macro-average stresses, the conventional stresses in the different layers can be obtained in sequence. The conventional stresses can then be utilized in a routine way for the strength and failure analysis. For the initial numerical modeling, the new Cosserat-like medium is reduced to a transversely isotropic one. The simplified constitutive model for layered media is then implemented into FLAC3D codes. A test sample validates that the results by using the numerical model are in good agreement with that by using the built-in model, and the mesh size for the new model is reduced greatly. Finally, an application for the stability of oil storage caverns in deep thinly bedded salt rocks is carried out. The effects on convergence of storage caverns and on the failure of surrounding rock due to the presence of the mudstone interlayers (hard phase) are discussed in detail. Copyright © 2009 John Wiley & Sons, Ltd. [source] A finite volume,multigrid method for flow simulation on stratified porous media on curvilinear co-ordinate systemsINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 4 2001Pablo Calvo Abstract This paper presents a numerical study of infiltration processes on stratified porous media. The study is carried out to examine the performance of a finite volume method on problems with discontinuous solutions due to the transmission conditions in the interfaces. To discretize the problem, a curvilinear co-ordinate system is used. This permits matching the interface with the boundary of the control volumes that interchange fluxes between layers. The use of the multigrid algorithm for the resulting systems of equations allows problems involving a large number of nodes with low computational cost to be solved. Finally, some numerical experiments, which show the capillary barrier behaviour depending on the material used for the different layers and the geometric design of the interface, are presented. Copyright © 2001 John Wiley & Sons, Ltd. [source] Proxy-assisted P2P and multicast transmission schemes for layered-video streaming over wireless networksINTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 9-10 2010Yung-Cheng Kao Abstract This work describes the process of efficiently streaming a set of layered-videos from a remote server via proxy of the base station to multiple heterogeneous and asynchronous clients in wireless networks, such as the WiMAX network, which are devices that request different layers of the video according to their profiles. The process focuses on that the transmission cost savings for caching X layers of a video are not only from requests on X layers, but also from requests on layers that are lower than X layers. A set of proxy-assisted transmission schemes are proposed for layered-video streaming by integrating the proxy caching with reactive transmission schemes, peer-to-peer mesh networks and base station multicast capability. The optimal proxy prefix cache allocation is calculated for each transmission scheme to identify the cache layer and cache length of each video to minimize the aggregate transmission cost. Experimental results demonstrate that an adaptive proxy-assisted transmission scheme can lead to significant transmission cost savings. Copyright © 2009 John Wiley & Sons, Ltd. [source] Cross-layer protocol optimization for satellite communications networks: a surveyINTERNATIONAL JOURNAL OF SATELLITE COMMUNICATIONS AND NETWORKING, Issue 5 2006Giovanni Giambene Abstract Satellite links are expected to be one important component of the next-generation Internet. New satellite system architectures are being envisaged to be fully IP based and support digital video broadcasting and return channel protocols (e.g. DVB-S, DVB-S2 and DVB-RCS). To make the upcoming satellite network systems fully realizable, meeting new services and application requirements, a complete system optimization is needed spanning the different layers of the OSI, and TCP/IP protocol stack. This paper deals with the cross-layer approach to be adopted in novel satellite systems and architectures. Different cross-layer techniques will be discussed, addressing the interactions among application, transport, MAC and physical layers. The impacts of these techniques will be investigated and numerical examples dealing with the joint optimization of different transport control schemes and lower layers will be considered referring to a geostationary-based architecture. Our aim is to prove that the interaction of different layers can permit to improve the higher-layer goodput as well as user satisfaction. Copyright © 2006 John Wiley & Sons, Ltd. [source] Differentiation of snake epidermis, with emphasis on the shedding layerJOURNAL OF MORPHOLOGY, Issue 2 2005Lorenzo Alibardi Abstract Little is known about specific proteins involved in keratinization of the epidermis of snakes. The presence of histidine-rich molecules, sulfur, keratins, loricrin, transglutaminase, and isopeptide-bonds have been studied by ultrastructural autoradiography, X-ray microanalysis, and immunohistochemistry in the epidermis of snakes. Shedding takes place along a shedding complex, which is composed of two layers, the clear and the oberhautchen layers. The remaining epidermis comprises different layers, some of which contain beta-keratins and others alpha-keratins. Weak loricrin, transglutaminase, and sometimes also iso-peptide-bond immunoreactivities are seen in some cells, lacunar cells, of the alpha-layer. Tritiated histidine is mainly incorporated in the shedding complex, especially in dense beta-keratin filaments in cells of the oberhautchen layer and to a small amount in cells of the clear layer. This suggests the presence of histidine-rich, matrix proteins among beta-keratin bundles. The latter contain sulfur and are weakly immunolabeled for beta-keratin at the beginning of differentiation of oberhautchen cells. After merging with beta cells, the dense beta-keratin filaments of oberhautchen cells become immunopositive for beta-keratin. The uptake of histidine decreases in beta cells, where little dense matrix material is present, while pale beta-keratin filaments increase. During maturation, little histidine labeling remains in electron-dense areas of the beta layer and in those of oberhautchen spinulae. Some roundish dense granules of oberhautchen cells rich in sulfur are negative to antibodies for alpha-keratin, beta-keratin, and loricrin. The granules eventually merge with beta-keratin, and probably contribute to the formation of the resistant matrix of oberhautchen cells. In conclusion, beta-keratin, histidine-rich, and sulfur-rich proteins contribute to form snake microornamentations. J. Morphol. © 2005 Wiley-Liss, Inc. [source] Application of ground-penetrating radar to determine the thickness of Pleistocene periglacial slope depositsJOURNAL OF PLANT NUTRITION AND SOIL SCIENCE, Issue 6 2004Daniela Sauer Abstract Wide areas of the mountainous regions of Germany have rock covered by Pleistocene periglacial slope deposits (PPSD), formed by gelifluction during the cold periods of the ice ages in non-glaciated areas. The PPSD provide the parent material for soil development, and their physical characteristics affect several stabile soil properties. Because the PPSD play a significant ecological role, we studied the spatial distribution and properties of the PPSD in order to assess the distribution of the stabile soil properties. The high stone content of the PPSD greatly hinders augering and digging. Hence, we tested the use of ground-penetrating radar (GPR) as a potentially time-saving, non-destructive method to determine the thickness of the PPSD. In several study areas of the Rhenish Massif, GPR investigations of single soil profiles and soil transects along an exposed gas-pipeline ditch were carried out. The GPR images were compared to the actual thickness of the layers of the PPSD exposed in the profiles and the ditch. In the GPR images usually at least one distinct boundary could be identified, which occurs at the transition between the loose material and the hard rock, mostly ranging between 50 and 150,cm depth. In some cases, in which stone content changed abruptly between different layers of the PPSD, also the boundaries between these layers could be identified in the GPR image. On the other hand, in areas where remnants of the Mesozoic-Tertiary weathering mantle are preserved, the boundary between the saprolite and the overlying basal layer of the PPSD is ambiguous or not at all visible. Einsatz von Georadar zur Bestimmung der Mächtigkeit periglaziärer Lagen In den deutschen Mittelgebirgen sind die Gesteine weitflächig von periglaziären Lagen überzogen. Diese entstanden durch Gelifluktion während der Kaltzeiten in den unvergletscherten Bereichen. Sie stellen das Ausgangssubstrat der Bodenbildung dar und bestimmen eine Reihe stabiler Bodeneigenschaften. Die ökologische Bedeutung der periglaziären Lagen gab den Anlass, ihre Verbreitung und Eigenschaften zu erfassen, um daraus flächenhafte Aussagen über diese Eigenschaften abzuleiten. Da Bohrungen und Grabungen in den periglaziären Lagen häufig durch hohe Skelettgehalte erschwert werden, wurde untersucht, ob Georadar zur zeitsparenden, zerstörungsfreien Erfassung der Lagenmächtigkeiten eingesetzt werden kann. In verschiedenen Teilen des Rheinischen Schiefergebirges wurden Georadar-Messungen an Bodenprofilen sowie an Transekten entlang eines Gasleitungsgrabens durchgeführt, die jeweils mit den Mächtigkeiten der periglaziären Lagen verglichen wurden, die an der Graben- bzw. Profilwand aufgeschlossen waren. In den Radargrammen ist in der Regel mindestens eine deutliche Grenze zu erkennen. Diese tritt am Übergang vom Lockermaterial zum Festgestein auf, der in der Regel zwischen 50 und 150,cm Tiefe liegt. In einigen Fällen, in denen sich der Skelettgehalt an den Lagengrenzen abrupt stark verändert, sind auch Grenzen zwischen verschiedenen Lagen im Radargramm zu erkennen. Dagegen ist in Gebieten, in denen Reste der mesozoisch-tertiären Verwitterungsdecke im Untergrund anstehen, die Grenze zwischen der Basislage und dem Gestein im Radargramm nur diffus oder nicht ausgeprägt. [source] A blueprint for the implementation of process-oriented knowledge managementKNOWLEDGE AND PROCESS MANAGEMENT: THE JOURNAL OF CORPORATE TRANSFORMATION, Issue 4 2003Ulrich Remus Process-oriented Knowledge Management aims at the integration of business processes and knowledge management. In order to provide knowledge for value adding activities within the business processes KM instruments and KM systems have to be adapted to business and knowledge processes. In detail, KM instruments such as content management, skill management, lessons learned, and communities have to be assigned to KM activities and processes. Models and patterns that describe generic pKM processes can build a blueprint for the implementation and support the stepwise integration of business processes into the knowledge life cycle. The introduction of a pKM becomes more efficient, as the flexibility is increased and the complexity is reduced. In this paper the authors show the essential elements of a blueprint developed during the implementation of a pKM in a large transaction bank. The blueprint describes the essential knowledge structures, activities, processes and instruments on different layers of abstraction in the context of a continuous knowledge life cycle. Copyright © 2003 John Wiley & Sons, Ltd. [source] Seven-band folded-loop chip antenna for WWAN/WLAN/WiMAX operation in the mobile phoneMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 2 2009Ming-Ren Hsu Abstract A chip antenna formed by using an FR4 chip base and a folded-loop metal pattern embedded therein for internal mobile phone antenna application is presented. The folded-loop metal pattern is embedded in two different layers inside the FR4 chip base to achieve a compact structure, and a coupling gap is introduced to successfully excite two wide operating bands at about 900 and 2000 MHz to cover GSM850/900/1800/1900/UMTS, 2.4-GHz WLAN, and 2.5-GHz WiMAX operations; that is, a seven-band internal mobile phone antenna for covering WWAN/WLAN/WiMAX operation is obtained. The proposed chip antenna also occupies a small volume of 4 × 5 × 40 mm3 (0.8 cm3) and shows a low profile of 5 mm when mounted on the system circuit board of the mobile phone, making it suitable for thin mobile phone applications. The proposed chip antenna is studied and tested. The SAR effect of the antenna is also analyzed in the study. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 543,549, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24063 [source] Changes in the Room-temperature Emission Spectrum of Chlorophyll During Fast and Slow Phases of the Kautsky Effect in Intact Leaves,PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 2 2005Fabrice Franck ABSTRACT Changes in the room-temperature emission spectrum of chlorophyll (Chl) were analyzed using fast diode-array recordings during the Kautsky effect in mature and in greening barley leaves. In mature leaves, the comparison of Fo (basal level of fluorescence yield at transient O) and FM (maximum level of fluorescence yield at transient M) spectra showed that the relative amplitude of total variable fluorescence was maximal for the 684 nm Photosystem II (PSII) band and minimal for the 725 nm Photosystem I band. During the increase from Fo to FM a progressive redshift of the spectrum of variable fluorescence occurred. This shift reflected the different fluorescence rise kinetics of different layers of chloroplasts inside the leaf. This was verified by simulating the effect of screening on the emission spectrum of isolated chloroplasts and by experiments on greening leaves with low Chl content. In addition, experiments performed at different greening stages showed that the presence of uncoupled Chl at early-greening stages and lightharvesting complex II (LHCII) at later stages have detectable but minor effects on the shape of room-temperature emission spectra. When strong actinic light was applied to mature green leaves, the slow fluorescence yield, which declined from FM to FT (steady-state level of fluorescence yield at transient T), was accompanied by a slight redshift of the 684 nm PSII band because of nonphotochemical quenching of short-wavelengthemitting Chl ascribed to LHCII. [source] Apical oxygen, 3D-2D cross over and superconductivity in Sm2,xCexCuO4,,PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 9 2006M. Boujida Abstract In spite of the vast amount of experimental and theoretical articles accumulated in HTSC, the mechanism of the interaction driving charge carriers to form Cooper pairs below Tc is still unknown. The comparison of the normal state transport properties of YBa2Cu3O7,, and the Sm2,xCexCuO4,, [1, 2] might shed some light on the microscopic origin of HTSC. In comparison to the YBCO, the apical oxygen in Sm2,xCexCuO4,, [3] destroys the superconductivity via the vertical ionic bonding which localizes the charge in the Cu-O squares, however the hole transfer by moving O(4) towards the CuO2 planes, leads to the optimization of YBCO properties. The behaviour of C axis parameter vs the oxygen content cannot be explained by a BSC mechanism. The high amount of anisotropy ratio [4] is explained by the sheer square planes in NCCO system, i.e. without apical oxygen (SC with Tc maximum). From the data of the resistivity in the normal state, we conclude the observation of a 3D-2D cross over only in Sm2,xCexCuO4,, [2] and Nd2,xCexCuO4,, [5] which is also related to its high anisotropy. The competition between anisotropy and superconductivity destroys the superconducting state in the 2D limit even in the ground state. In this material the superconductivity cannot be enhanced at high temperature because the compound is a quasi 2D system (sheer square planes of CuO2) and the cuprate superconductors is a genuine three-dimensional (3D) phenomenon [6]. The Josephson coupling between the different layers is S-I-S for NCCO and S-N-S for YBCO, thus the Lawrence and Doniach model (LD) [7] with neighbouring layers coupled by the Josephson tunnelling is appropriate. In summary the behaviour of apical oxygen is intrinsically different in the two kinds of cuprates. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Magnetic anisotropy studies on FeNiCo/Ta/FeNiCo three layers film by layer sensitive ferromagnetic resonance techniquePHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 12 2004F. Yildiz Abstract Two ferromagnetic layers that are separated by a non-magnetic spacer have been deposited in the presence of an external Dc magnetic field that has been applied in a mutually perpendicular direction during the deposition of each layer. This thin three-layer film of FeNiCo/Ta/FeNiCo was then studied by electron spin resonance (ESR) technique for different directions of the external magnetic field with respect to the film plane. Beside very anisotropic and strong two main modes, relatively well-resolved and very weak subsidiary peaks in ESR spectra were observed on low field side of the main modes for almost every direction of the external field. The anisotropic behavior as the field is rotated from the film normal towards to the film plane is due to strong demagnetizing field. However, two fold (axial) small anisotropies having 90 degrees phase shifts with respect to the peaks from two different layers were seen to originate from field-induced anisotropy. The small peaks are attributed to magnetostatics modes as well. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Changes in leaf photosynthetic parameters with leaf position and nitrogen content within a rose plant canopy (Rosa hybrida)PLANT CELL & ENVIRONMENT, Issue 4 2000M. M. Gonzalez-Real ABSTRACT This paper deals with changes in leaf photosynthetic capacity with depth in a rose (Rosa hybrida cv. Sonia) plant canopy. Measurements of leaf net CO2 assimilation (Al) and total nitrogen content (Nl) were performed in autumn under greenhouse conditions on mature leaves located at different layers within the plant canopy, including the flower stems and the main shoots. These leaves were subjected (i) to contrasting levels of CO2 partial pressure (pa) at saturating photosynthetic photon flux density (I about 1000 ,mol m,2 s,1) and (ii) to saturating CO2 partial pressure (pa about 100 Pa) and varying I, while conditions of temperature were those prevailing in the greenhouse (20,38 °C). A biochemical model of leaf photosynthesis relating Al to intercellular CO2 partial pressure (pi) was parameterized for each layer of leaves, supplying corresponding values of the photosynthetic Rubisco capacity (Vlm) and the maximum rate of electron transport (Jm). The results indicated that rose leaves growing at the top of the canopy had higher values of Jm and Vlm, which resulted from a higher allocation of nitrogen to the uppermost leaves. Mean values of total leaf nitrogen, Nl, decreased about 35% from the uppermost leaves of flower stem to leaves growing at the bottom of the plant. The derived values of non-photosynthetic nitrogen, Nb, varied from 76 mmolN m,2leaf (layer 1) to 60 mmolN m,2leaf (layer 4), representing a large fraction of Nl (50 and 60% in layer 1 and 4, respectively). Comparison of leaf photosynthetic nitrogen (Np=Nl,Nb) and I profiles supports the hypothesis that rose leaves acclimate to the time-integrated absorbed I. The relationships between I and Np, obtained during autumn, spring and summer, indicate that rose leaves seem also to acclimate their photosynthetic capacity seasonally, by allocating more photosynthetic nitrogen to leaves in autumn and spring than in summer. [source] Motivations, Goals, Information Search, and Memory about Political CandidatesPOLITICAL PSYCHOLOGY, Issue 4 2001Li-Ning Huang This study investigated the ways in which motivations and goals affect patterns of political information-seeking and the consequent structure of memory about candidates. Undergraduate participants used a computerized system that displayed different layers of information about fictional political candidates; the system recorded the strategies they used to search through this information. Results showed that motivations to engage in effortful processing produced tendencies to engage in within-candidate searches, better recall, and memory structures clustered by candidate. The goal of forming impressions of the candidates, which was expected to lead to within-candidate searching, was in fact modestly associated with weaker tendencies to do so, once effort was taken into account. Impression-formation goals, however, were associated with less attribute-based memory structures. The findings confirm that the manner in which people acquire candidate information has important consequences for the way they store that information in memory, and that these processes vary according to individual motivations and goals. [source] Thin-film solar cells: an overviewPROGRESS IN PHOTOVOLTAICS: RESEARCH & APPLICATIONS, Issue 2-3 2004K. L. Chopra Abstract Thin film solar cells (TFSC) are a promising approach for terrestrial and space photovoltaics and offer a wide variety of choices in terms of the device design and fabrication. A variety of substrates (flexible or rigid, metal or insulator) can be used for deposition of different layers (contact, buffer, absorber, reflector, etc.) using different techniques (PVD, CVD, ECD, plasma-based, hybrid, etc.). Such versatility allows tailoring and engineering of the layers in order to improve device performance. For large-area devices required for realistic applications, thin-film device fabrication becomes complex and requires proper control over the entire process sequence. Proper understanding of thin-film deposition processes can help in achieving high-efficiency devices over large areas, as has been demonstrated commercially for different cells. Research and development in new, exotic and simple materials and devices, and innovative, but simple manufacturing processes need to be pursued in a focussed manner. Which cell(s) and which technologies will ultimately succeed commercially continue to be anybody's guess, but it would surely be determined by the simplicity of manufacturability and the cost per reliable watt. Cheap and moderately efficient TFSC are expected to receive a due commercial place under the sun. Copyright © 2004 John Wiley & Sons, Ltd. [source] Protamine ratio and the level of histone retention in sperm selected from a density gradient preparationANDROLOGIA, Issue 2 2009S. Hammoud Summary Fertile males express two forms of sperm nuclear proteins, protamine 1 (P1) and protamine 2 (P2), in roughly equal quantities, whereas some infertile men have been shown to have a reduction in protamine content and an increase in the level of histones retained in mature sperm. In this study, we assessed histone and protamine levels in spermatozoa isolated from different layers of a density gradient centrifugation column to evaluate the nuclear protein content of the sperm population selected. Protamine levels were measured using acid gel electrophoresis and immunofluorescence, and the percentage of cells retaining histones was evaluated using aniline staining and immunofluorescence. Our data suggests that there is an inverse correlation between P1/P2 ratio and the level of histone expression in the different layers of the density gradient. Paradoxically, the 90% layer had a lower P1/P2 ratio, which corresponded with an increase in histone expression. It is concluded that although the sperm population selected in the 90% layer of the density gradient columns had a lower P1/P2 ratio, it was yet similar to the P1/P2 ratio observed in previously screened fertile donors. [source] Differences between Ventricular Repolarization in Men and Women: Description, Mechanism and ImplicationsANNALS OF NONINVASIVE ELECTROCARDIOLOGY, Issue 4 2003Borys Surawicz M.D., M.A.C.C. The purpose of this review article is to discuss the differences between ventricular repolarization in males and females in terms of morphology, possible mechanism, and practical significance. The interest in the subject increased when it became known that in comparison to men, women have a higher incidence of torsade de pointes (tdp) and a greater lengthening of QT-interval after administration of class III antiarrhythmic drugs. Before puberty, the QT intervals and the patterns of ventricular repolarization in boys and girls are similar. At puberty, in boys the QT interval shortens, and a typical male pattern of ventricular repolarization develops. This pattern is characterized by a higher amplitude of the J-point, a shorter and steeper ST segment course, a steeper ascent, and a higher amplitude of the T wave. This pattern is prevalent in >90% of young males. With increasing age the prevalence of the male pattern in males declines gradually and drops to 14% in the oldest age group. The rise and fall of the prevalence of the male pattern appears to parallel the rise and decline of testosterone in males. The female pattern of ventricular repolarization is prevalent in about 80% of females in all age groups. The hormonal effects on ventricular repolarization have been studied in normal and castrated rabbits of both sexes. The available evidence indicates that the females have greater divergence of L calcium current among different layers of the myocardium and a lower density of the repolarizing Kr and Ks currents. The clinical significance of the repolarization differences among genders remains to be determined. Of particular interest is the question whether the males with female pattern are at the same risk of tdp as the females or whether the females with male pattern are at lower risk of tdp than the females with female pattern. [source] Synthetic aenigmatite analog Na2(Mn5.26Na0.74)Ge6O20: structure and crystal chemical considerationsACTA CRYSTALLOGRAPHICA SECTION C, Issue 3 2008Günther J. Redhammer Disodium hexamanganese(II,III) germanate is the first aenigmatite-type compound with significant amounts of manganese. Na2(Mn5.26Na0.74)Ge6O20 is triclinic and contains two different Na positions, six Ge positions and 20 O positions (all with site symmetry 1 on general position 2i of space group P). Five out of the seven M positions are also on general position 2i, while the remaining two have site symmetry (Wyckoff positions 1f and 1c). The structure can be described in terms of two different layers, A and B, stacked along the [011] direction. Layer A contains pyroxene-like chains and isolated octahedra, while layer B is built up by slabs of edge-sharing octahedra connected to one another by bands of Na polyhedra. The GeO4 tetrahedra show slight polyhedral distortion and are among the most regular found so far in germanate compounds. The M sites of layer A are occupied by highly charged (trivalent) cations, while in layer B a central pyroxene-like zigzag chain can be identified, which contains divalent (or low-charged) cations. This applies to the aenigmatite-type compounds in general and to the title compound in particular. [source] | ||||||||||||||||||||||||||||