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Available Space (available + space)
Selected AbstractsInfluences of Aquifer Properties on Flow Dimensions in DolomitesGROUND WATER, Issue 5 2009Timotej Verbov The paper focuses on analyses and correlations of flow dimensions in different dolomite aquifers in Slovenia. Flow dimensions are obtained through the reinterpretation of 72 pumping tests with the generalized radial flow model, based on the fractional flow dimension. The average value of flow dimensions is 2.16 for all dolomites. A study of flow dimensions in individual aquifers categorized according to their lithological properties shows that higher dimensions occur in massive late-diagenetic Cordevolian and Anisian dolomites compared with bedded Main, Ba,a, and especially Lower Triassic dolomites, which contain a greater proportion of noncarbonate minerals. Partially penetrating wells have higher flow dimensions than fully penetrating wells. Flow dimensions are poorly correlated with hydraulic conductivities of fractures. When comparing the quantities of major dissolved minerals, obtained by hydrogeochemical inverse modeling, with the values of flow dimensions, the Cordevolian and Anisian dolomites are found to exhibit the highest values of both dissolved dolomite and flow dimensions, indicating that greater dissolution occurs at higher flow dimensions. For other aquifers, data points are more scattered and the correlation is mostly poor. When compared with three-dimensional fractal dimensions of fracture networks, there is no correlation with flow dimensions. However, almost all the values of flow dimensions are lower than the corresponding fractal dimensions in dolomites (average D= 2.77), possibly indicating the channeling of flow within the available space of the fracture networks, consequently reducing the flow dimensions. [source] Performance evaluation of CSMA/ID MAC protocol for IP over WDM ring networksINTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 11 2008Jih-Hsin Ho Abstract In this paper, a packet pre-classification media access control protocol based on a carrier sense multiple access with idle detection (CSMA/ID) scheme is investigated for supporting IP packets over all-optical WDM ring networks. The purpose of the protocol is to increase throughput and to decrease the packet transmission delay of IP packets over optical networks in a metropolitan area network. This protocol avoids both packet collision and packet fragmentation. In order to improve the utilization of the network, the packets transmitted from a local area network are first pre-classified into various class queues of an access point (AP) according to their length. After checking the available space based on the wavelength received by the receivers of the AP, the packets in the queues are transmitted. An analytical model is developed to evaluate the performance of the protocol, with simulation results showing good network efficiency. The proposed network has short-term variations that introduce unfairness conditions. This problem could be overcome by assigning a quota on individual queues to allow all queues fair access. Copyright © 2008 John Wiley & Sons, Ltd. [source] Can selection on nest size from nest predation explain the latitudinal gradient in clutch size?JOURNAL OF ANIMAL ECOLOGY, Issue 5 2010Luis Biancucci Summary 1.,Latitudinal variation in clutch sizes of birds is a well described, but poorly understood pattern. Many hypotheses have been proposed, but few have been experimentally tested, and none have been universally accepted by researchers. 2.,The nest size hypothesis posits that higher nest predation in the tropics favours selection for smaller nests and thereby constrains clutch size by shrinking available space for eggs and/or nestlings in the nest. We tested this hypothesis with an experiment in a tropical forest and a comparative study between temperate and tropical field sites. 3.,Specifically, we tested if: (i) predation increased with nest size; (ii) tropical birds had smaller nests controlled for body size; and (iii) clutch size was explained by nest size controlled for body size. 4.,Experimental swapping of nests of different sizes showed that nest predation increased with nest size in the tropical site. Moreover, nest predation rates were higher in species with larger nests in both sites. However, nest size, corrected for body mass and phylogeny, did not differ between sites and was not related to clutch size between sites. 5.,Hence, nest predation can exert selection on nest size as predicted by the hypothesis. Nest size increased with adult body mass, such that adult size might indirectly influence reproductive success through effects on nest size and nest predation risk. Ultimately, however, selection from nest predation on nest size does not explain the smaller clutch sizes typical of the tropics. [source] Evaluation of interarch space for implant restorations in edentulous patients: A laboratory techniqueJOURNAL OF PROSTHODONTICS, Issue 2 2000Nicolas F. AbuJamra DDS This article describes a laboratory procedure for the visual evaluation of interarch space and its effect on implant prosthesis design. The method is applicable to patients presenting with completely edentulous arches. Silicone impression material is used to form a resilient cast and an external mold from an existing denture. The denture is duplicated using autopolymerizing acrylic resin. The duplicate denture and resilient cast are mounted on an articulator. Spatial relationships of anatomic landmarks can be evaluated, and a quantitative evaluation of available space can be made. The duplicate denture can also be used as a surgical template to direct implant placement. Reference tables are provided to serve as guidelines in the correlation between available space and minimum space required for various implant-assisted restorations. [source] Structural formation of hybrid siloxane-based polymer monolith in confined spacesJOURNAL OF SEPARATION SCIENCE, JSS, Issue 10-11 2004Kazuyoshi Kanamori Abstract Structural deformation of phase-separated methylsiloxane gel under the influence of a surface has been studied. Competitive wetting of siloxane gel phase on a surface during phase formation is found to significantly affect the final morphology in a confined space. When the spinodal wavelength is sufficiently shorter than the size of the available space, a uniform bicontinuous structure forms in confined geometry. However, gel skeletons in the vicinity of a surface are elongated with decreasing size of the space, and finally when the size of the space becomes shorter than the spinodal wavelength, all the gel phase wets on a surface, showing a "wetting transition". Homogeneous bicontinuous methylsiloxane gels were successfully prepared, avoiding such structural deformation, in a long cylindrical fused silica capillary and used for capillary HPLC. The capillary gels exhibited excellent separation efficiency of nitrobenzenes and it was found that the surface character can be altered by incorporating surfactants, which will enable more advanced and extended control of surface character, depending on the analytes. [source] Starch,poly(,-caprolactone) and starch,poly(lactic acid) fibre-mesh scaffolds for bone tissue engineering applications: structure, mechanical properties and degradation behaviourJOURNAL OF TISSUE ENGINEERING AND REGENERATIVE MEDICINE, Issue 5 2008M. E. Gomes Abstract In scaffold-based tissue engineering strategies, the successful regeneration of tissues from matrix-producing connective tissue cells or anchorage-dependent cells (e.g. osteoblasts) relies on the use of a suitable scaffold. This study describes the development and characterization of SPCL (starch with ,-polycaprolactone, 30:70%) and SPLA [starch with poly(lactic acid), 30:70%] fibre-meshes, aimed at application in bone tissue-engineering strategies. Scaffolds based on SPCL and SPLA were prepared from fibres obtained by melt-spinning by a fibre-bonding process. The porosity of the scaffolds was characterized by microcomputerized tomography (µCT) and scanning electron microscopy (SEM). Scaffold degradation behaviour was assessed in solutions containing hydrolytic enzymes (,-amylase and lipase) in physiological concentrations, in order to simulate in vivo conditions. Mechanical properties were also evaluated in compression tests. The results show that these scaffolds exhibit adequate porosity and mechanical properties to support cell adhesion and proliferation and also tissue ingrowth upon implantation of the construct. The results of the degradation studies showed that these starch-based scaffolds are susceptible to enzymatic degradation, as detected by increased weight loss (within 2 weeks, weight loss in the SPCL samples reached 20%). With increasing degradation time, the diameter of the SPCL and SPLA fibres decreases significantly, increasing the porosity and consequently the available space for cells and tissue ingrowth during implantation time. These results, in combination with previous cell culture studies showing the ability of these scaffolds to induce cell adhesion and proliferation, clearly demonstrate the potential of these scaffolds to be used in tissue engineering strategies to regenerate bone tissue defects. Copyright © 2008 John Wiley & Sons, Ltd. [source] Students' perceptions of relationships between some educational variables in the out-patient settingMEDICAL EDUCATION, Issue 8 2002D H J M Dolmans Background Medical education uses the cognitive apprenticeship model of student learning extensively. Students rotate among different hospitals and out- patient clinics where they are exposed to a range of professionally relevant contexts. Here they learn to think and act in different domains under the supervision of experts. Previous research has shown that these learning situations involve little teaching. Students see a narrow range of patient problems and feedback is limited. The aim of this study is to investigate relationships among some educational variables in the out-patient clinic. Method This paper provides a theoretical model that specifies the factors influencing the effectiveness of student rotations at out-patient clinics. The model makes distinctions between input variables, such as organizational quality, number of students contemporaneously involved and available space, and process variables, such as patient mix and supervision, and the output variable of the effectiveness of rotations in out-patient clinics. Results The model was tested against empirical data from evaluative surveys and showed a reasonable fit. The model offers suggestions for improving the learning environment of clinical rotations. Discussion The strength of this study lies in its process evaluation perspective which investigates interactions between intervening variables rather than the influence of particular variables in isolation from other variables. [source] Palmaris profundus: One name, several subtypes, and a shared potential for nerve compressionCLINICAL ANATOMY, Issue 6 2009Elena Pirola Abstract The palmaris profundus is a rare, but known anatomic variation which may lead to compression of the median nerve and/or its branches. Two patients with carpal tunnel syndrome are presented in whom a palmaris profundus was discovered at operation. In these cases, median nerve compression at the wrist was attributed to the course of the extra tendon and its local mass effect on the nerve (i.e., the palmaris profundus and median nerve shared a common sheath); more commonly, the resultant decreased available space for the median nerve within the carpal tunnel due to the presence of an accessory (10th) flexor tendon is thought to be responsible. Postoperative 3 Tesla magnetic resonance imaging (MRI) was performed to demonstrate the full course of the variant muscle; despite variations in the size and longitudinal extent of the accessory musculotendinous unit, an important similarity was noted: the intimate relationship of the median nerve and the palmaris profundus. These two cases and our review of the literature highlight the fact that one name (i.e. palmaris profundus) reflects several anatomic subtypes. However, the close relationship of the palmaris profundus with the median nerve in the forearm and the palm is a common theme which emphasizes the potential pathoanatomic consequences of this relationship: nerve compression. Clin. Anat. 22:643,648, 2009. © 2009 Wiley-Liss, Inc. [source] | ||||||||||||||||