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Very Large (very + large)
Terms modified by Very Large Selected AbstractsOut-of-core compression and decompression of large n -dimensional scalar fieldsCOMPUTER GRAPHICS FORUM, Issue 3 2003Lawrence Ibarria We present a simple method for compressing very large and regularly sampled scalar fields. Our method is particularlyattractive when the entire data set does not fit in memory and when the sampling rate is high relative to thefeature size of the scalar field in all dimensions. Although we report results foranddata sets, the proposedapproach may be applied to higher dimensions. The method is based on the new Lorenzo predictor, introducedhere, which estimates the value of the scalar field at each sample from the values at processed neighbors. The predictedvalues are exact when the n-dimensional scalar field is an implicit polynomial of degreen, 1. Surprisingly,when the residuals (differences between the actual and predicted values) are encoded using arithmetic coding,the proposed method often outperforms wavelet compression in anL,sense. The proposed approach may beused both for lossy and lossless compression and is well suited for out-of-core compression and decompression,because a trivial implementation, which sweeps through the data set reading it once, requires maintaining only asmall buffer in core memory, whose size barely exceeds a single (n,1)- dimensional slice of the data. Categories and Subject Descriptors (according to ACM CCS): I.3.5 [Computer Graphics]: Compression, scalar fields,out-of-core. [source] Application of High Current and Current Zero Simulations of High-Voltage Circuit BreakersCONTRIBUTIONS TO PLASMA PHYSICS, Issue 10 2006C. M. Franck Abstract This paper reports on the use of computational fluid dynamic (CFD) simulations to predict the interruption behaviour of high-voltage circuit breakers (HV-CB) using the self-blast principle. Two different levels of accuracy of the arc model are proven to be sufficiently accurate for simulating the high-current phase and the period around current zero (CZ). For the high-current phase, a simplified equivalent model of the arc is implemented to predict the pressure build-up, and even more important to accurately trace the hot gas from the arcing zone into the exhausts and the heating volume. A detailed analysis of the gas mixing in the heating volume for different arcing times and current amplitudes showed the optimum geometrical design of the heating volume. For the CZ phase, a more detailed arc model is needed including the effects of ohmic heating, radiative energy transfer, and turbulent cooling fully resolved in space and time. The validation with experiments was done and shows good agreement which justifies the use of the implemented model. With it, scaling laws varying only one parameter at a time (pressure and applied current slope) were derived and confirm previously found empirical laws. This is of particular interest, as it is very difficult to derive such scaling laws from experiments where the scatter is always very large and where it is impossible to vary only one parameter at a time. The influence of the most important geometrical parameters of the nozzle on the interruption performance is shown. In addition to previous experimental indications of this, the simulation reveals that turbulent cooling on the arc edge is the main reason for the difference in interruption performance. Moreover, the exact spatio-temporal build-up of arc resistance and with it the detailed understanding of the arc interruption process is possible and shown here for the first time. These simulations enable us to predict HV-CB performance and to minimise the number of development tests and are routinely used in new development projects. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Mesothelioma Symposium 11.30,12.30 Tuesday 16 September 2003CYTOPATHOLOGY, Issue 2003Darrel Whitaker Dr The diagnosis of malignant mesothelioma on the cytology of serous effusions is a two-phase process. First is to determine that the effusion is malignant based on morphological features such as a highly cellular fluid with many large three dimensional cell aggregates, and/or the recognition of minor malignant criteria including prominent cell engulfment, uniformly present very prominent nucleoli, or the finding of very large (giant) cells. In cell block sections, strong positive staining with EMA often with cell membrane accentuation provides compelling support for a cytological diagnosis of malignancy. Second is to recognize that the malignant cells have a mesothelial phenotype and do not represent metastatic malignancy (usually adenocarcinoma). Criteria in support of mesothelioma include the lack of a ,two cell' population, that is one native (mesothelial) and one foreign (metastatic), cells with abundant dense staining cytoplasm, the presence of ,windows' where mesothelioma cells lie in close apposition and intracytoplasmic glycogen presenting either as small peripheral vacuoles on MGG stained smears or large yellow refractile crescents on Papanicolaou stained smears. In addition, mesothliomas often possess connective tissue stromal cores occurring as either well-formed collagen within papillary aggregates or lying free as pink (MGG) or light green (Pap) amorphous material in the background of the smear or in loose association with mesothelioma cells. Finally small orange staining squamous-like cells can occasionally be identified and sometimes this may be a very prominent finding and has resulted in the false impression of a squamous cell carcinoma. Almost certainly these cells represent apoptotic tumour cells. The connective tissue mucin hyaluronic acid may be found as a net-like pattern in the smear background or as large hard-edged magenta-stained vacuoles on MGG-stained smears. Cell block sections provide architectural information and it is usually possible to separate mesothelioma aggregates with their cuboidal cells, central nuclei and abundant dense cytoplasm arranged in solid, papillary or hollow clusters from those of adenocarcinoma with less dense, often foamy cytoplasm, often composed of columnar cells with elongated nuclei. Aggregate form in adenocarcinoma can be variable but true acini are a rare finding. These cell block sections provide an ideal medium for histochemistry (PAS with and without diastase digestion) and immunocytochemistry. By using a panel of antibodies (Calretinin and CK 5/6, BerEp4, CEA, B72.3) it is almost always possible to distinguish mesothelioma from metastatic adenocarcinoma. Calretinin and CK 5/6 positive staining and absent staining with BerEp4, CEA and B72.3 is considered diagnostic of mesothelioma. [source] Port-Wine Stain Nodules in the Adult: Report of 20 Cases Treated by CO2 Laser VaporizationDERMATOLOGIC SURGERY, Issue 8 2001Jesús Del Pozo MD Background. Port-wine stain (PWS) is a congenital vascular malformation of the superficial dermal vessels. These vessels become progressively ectatic, with development of nodular and hypertrophic areas on the surface of the lesions. Objective. To determine the efficacy of CO2 laser vaporization in the treatment of nodules in PWS. Methods. Twenty adult patients with PWS who developed nodules and hypertrophy on the surface of the lesions were treated by CO2 laser vaporization. Only one pass was performed to each area of the lesions, using a continuous and defocused mode, with a power density of 10 W/cm2. When the treated lesion was very large, several sessions of treatment were necessary to vaporize its entire surface. Photographic controls were performed before and after treatment. Results. The nodules and hypertrophy were removed and the smooth surface of the lesions was reestablished. The color, usually violaceous, was transformed in a slight erythema. Conclusion. CO2 laser is a good method for treatment of nodules and hypertrophy in PWS. With adequate precautions, excellent cosmetic results can be obtained. Other more-specific laser systems may be successively used to treat the remaining erythema. [source] Ultrastructure of spermatozoa of lizards in the genus Mabuya from Central BrazilACTA ZOOLOGICA, Issue 1 2009S. M. De Sá Mandel Abstract This is the first description of spermatozoal ultrastructure of Mabuya skinks. The spermatozoa of the species studied are filiform, consisting of a head region, a midpiece and a tail. The head is characterized by the following features: a depressed acrosome anteriorly, an acrosome vesicle divided into cortex and medulla, paracrystalline subacrosomal material, a pointed tip perforatorium, a circular perforatorium base plate inside the subacrosomal cone, an epinuclear lucent zone separated from the subacrosomal cone by a membrane, a large nuclear rostrum, and round nuclear shoulders. The midpiece presents a bilateral stratified laminar structure, a distal centriole, peripheral fibres 3 and 8 grossly enlarged, columnar mitochondria with linear cristae, dense body rings and a triangular annulus. Finally, the tail is composed of a principal piece and an end piece. An axoneme and a fibrous sheath characterize the principal piece, and the end piece is formed only by an axoneme, which loses its pattern in the last portion. Comparisons with members of Teiidae revealed differences in the numbers of dense rings. A well-developed epinuclear lucent zone in Mabuya is less prominent among teiids. In the spermatozoa of Mabuya, the first ring of dense bodies is very large, uniquely resembling the condition present in snakes. [source] Arthroscopic laser extirpation of metacarpophalangeal synovial pad proliferation in eleven horsesEQUINE VETERINARY JOURNAL, Issue 3 2001D. J. MURPHY Summary A new surgical technique for treatment of chronic metacarpophalangeal synovial pad proliferation in the horse and the findings and long-term follow-up from 11 clinical cases are described. The medical records of all equine lameness cases attributed to metacarpophalangeal synovial pad proliferation admitted to the College of Veterinary Medicine at Cornell University (1991,1996) were reviewed and all those treated surgically by laser extirpation were included in this study. Retrieved data included subject details, preoperative lameness, ultrasonography, radiography and synovial fluid evaluations and lesion histopathology. Lesions were ablated using a CO2 or a Nd:YAG laser intra-articularly with arthroscopic guidance. Long-term follow-up was provided by telephone conversation with owners or trainers. All horses had fetlock joint effusion and were lame at presentation. Mean synovial pad thickness measured ultrasonographically was 9.0 mm (range 6,15 mm). Seven horses (64%) had radiographic evidence of remodelling of the dorsal cortex of distal McIII and 3 horses (27%) had concurrent dorsal proximal P1 fractures. No postoperative complications were noted. All 11 horses returned to training within 90 days of surgery without recurrence of the lesion(s). Laser extirpation of metacarpophalangeal synovial pad proliferation using arthroscopic guidance provided a rapid, safe and efficient method for surgical removal of such lesions without complications or recurrence. This surgical technique provides a suitable alternative to more conventional treatments for chronic metacarpophalangeal synovial pad proliferation in horses, particularly for removal of very large, fibrotic masses. [source] Reduced smoking: an introduction and review of the evidenceADDICTION, Issue 1s1 2000John R. Hughes The major questions about reductions in the number of cigarettesday as a treatment goal are (1) how many smokers can reduce and maintain such reduction, (2) how much compensation will occur, (3) will reduced smoking significantly decrease the risk of smoking and (4) will reduction promote or undermine cessation. Naturalistic studies of smokers who are not trying to stop smoking indicate that a substantial minority of smokers spontaneously reduce their number of cigarettesday and can maintain significant reductions (-7% to -43%) over long periods of time. Six experimental trials of smokers not interested in quitting were able to induce large reductions in cigarettesday (-15% to -63%) using behavioral therapy andor nicotine replacement. Reductions in toxin exposure (carbon monoxide) were not as large but still substantial (-21% to -35%). The three studies with long-term follow-ups found little loss of effects over 6-30 months. Although face-valid, there is no direct test of whether reduced smoking will decrease smoking risks and such a study would need to be very large and last for a long time. None of the above-cited studies indicate that reduction undermines the probability of future cessation attempts and several found reduction promotes future cessation. [source] Effects of pressure on the activity and spectroscopic properties of carboxyl proteinasesFEBS JOURNAL, Issue 3 2001Apparent correlation of pepstatin-insensitivity, pressure response The pressure dependence of the activity and spectroscopic properties of four carboxyl proteinases were investigated. Two were pepstatin-sensitive carboxyl proteinases (porcine pepsin and proteinase A from baker's yeast) and two were pepstatin-insensitive carboxyl proteinases (from Pseudomonas sp. 101 (pseudomonapepsin; PCP) and Xanthomonas sp. T-22 (xanthomonapepsin; XCP)). The specificity constant [kcat/Km(app)] of PCP and XCP for a synthetic peptide substrate showed only a slight decrease with increasing pressure, whereas pepsin and proteinase A showed substantial disactivation at higher pressures. The calculated apparent activation volume (,Vkcat/Km) was about 1, 3, 13, and 14 mL·mol,1 for PCP, XCP, pepsin, and proteinase A, respectively. The hydrolysis of acid-denatured myoglobin by the four carboxyl proteinases was only slightly affected by high pressure (except for proteinase A at 400 MPa), in contrast to the results for the peptide hydrolysis. In fact, PCP, XCP, and proteinase A actually showed slightly higher degradations of acid-denatured myoglobin at higher pressures. The residual activities of these enzymes after the incubation at high pressures implied a pressure-induced stabilization towards autolysis. The changes in the fourth derivative near-UV absorbance spectrum of the four enzymes in aqueous solution were measured at various pressures from 0.1 to 400 MPa. Upon an increase in pressure, the peaks from PCP and XCP red-shifted slightly, whereas pepsin and proteinase A blue-shifted substantially, thus indicating a more polar environment. The intrinsic fluorescence also decreased upon increasing pressure. However, the change for XCP was rather small, but the change for the other three was very large. The changes in the peak wavelength for pepsin and proteinase A were characteristic, and also indicated a more polar environment under high pressure. An analysis by the center of spectra mass (CSM) gave the ,G and ,V of transition as 9.8 kJ·mol,1 and ,24 mL·mol,1 (pepsin) and 11.7 kJ·mol,1 and ,43 mL·mol,1 (proteinase A), respectively, by assuming a simple two-state transition. The circular dichroism (CD) showed relatively small changes after 1-h incubations at 400 MPa, indicating that the secondary structures were largely maintained. [source] Nonlocal quantum gravity and the size of the universeFORTSCHRITTE DER PHYSIK/PROGRESS OF PHYSICS, Issue 6-7 2004M. Reuter Motivated by the conjecture that the cosmological constant problem is solved by strong quantum effects in the infrared we use the exact flow equation of Quantum Einstein Gravity to determine the renormalization group behavior of a class of nonlocal effective actions. They consist of the Einstein-Hilbert term and a general nonlinear function Fk(V) of the Euclidean spacetime volume V. For the V + V ln V -invariant the renormalization group running enormously suppresses the value of the renormalized curvature which results from Planck-size parameters specified at the Planck scale. One obtains very large, i.e., almost flat universes without finetuning the cosmological constant. A critical infrared fixed point is found where gravity is scale invariant. [source] Infiltration of basinal fluids into high-grade basement, South Norway: sources and behaviour of waters and brinesGEOFLUIDS (ELECTRONIC), Issue 1 2003S. A. Gleeson Abstract Quartz veins hosted by the high-grade crystalline rocks of the Modum complex, Southern Norway, formed when basinal fluids from an overlying Palaeozoic foreland basin infiltrated the basement at temperatures of c. 220°C (higher in the southernmost part of the area). This infiltration resulted in the formation of veins containing both two-phase and halite-bearing aqueous fluid inclusions, sometimes with bitumen and hydrocarbon inclusions. Microthermometric results demonstrate a very wide range of salinities of aqueous fluids preserved in these veins, ranging from c. 0 to 40 wt% NaCl equivalent. The range in homogenization temperatures is also very large (99,322°C for the entire dataset) and shows little or no correlation with salinity. A combination of aqueous fluid microthermometry, halogen geochemistry and oxygen isotope studies suggest that fluids from a range of separate aquifers were responsible for the quartz growth, but all have chemistries comparable to sedimentary formation waters. The bulk of the quartz grew from relatively low ,18O fluids derived directly from the basin or equilibrated in the upper part of the basement (T < 200°C). Nevertheless, some fluids acquired higher salinities due to deep wall-rock hydration reactions leading to salt saturation at high temperatures (>300°C). The range in fluid inclusion homogenization temperatures and densities, combined with estimates of the ambient temperature of the basement rocks suggests that at different times veins acted as conduits for influx of both hotter and colder fluids, as well as experiencing fluctuations in fluid pressure. This is interpreted to reflect episodic flow linked to seismicity, with hotter dry basement rocks acting as a sink for cooler fluids from the overlying basin, while detailed flow paths reflected local effects of opening and closing of individual fractures as well as reaction with wall rocks. Thermal considerations suggest that the duration of some flow events was very short, possibly in the order of days. As a result of the complex pattern of fracturing and flow in the Modum basement, it was possible for shallow fluids to penetrate basement rocks at significantly higher temperatures, and this demonstrates the potential for hydrolytic weakening of continental crust by sedimentary fluids. [source] Correlation between sea surface topography and bathymetry in shallow shelf waters in the Western MediterraneanGEOPHYSICAL JOURNAL INTERNATIONAL, Issue 3 2002G. Rodríguez Velasco Summary In this paper, gravimetric and altimetric data are used to assess an estimation of the sea surface topography in the Western Mediterranean Sea. This is a complex area from different points of view, due to the presence of several islands, coastal lines, shallow waters and a peculiar hydrologic equilibrium due to its proximity to the Atlantic water exchange area. First, a gravimetric geoid was computed using the least-squares collocation (LSC) procedure with the classical remove-restore technique. We also present a local mean sea surface generated from repeat ERS-1 altimeter data fitted to TOPEX. We chose this satellite because it offers a better spatial resolution than the TOPEX data. The time span used in the computations is one year. This is a useful interval for averaging out the regular seasonal variations, which are very large in this area. We present the comparisons between the gravimetric geoidal heights and the adjusted sea surface. This is a way to obtain a rough estimation of the sea surface topography (SST) since we also include the errors in the two surfaces and other oceanic signals. The differences obtained are physically reasonable with a mean of 17 cm and standard deviation (s.d.) of 39 cm. A significant similarity is observed between the features reproduced by these differences and the bathymetry in the area, suggesting some sort of correlation between both magnitudes for the studied region. If we accept such correlation, the SST may be described as a function of depth. This procedure lets us filter out the short wavelength part of the geoid from the first SST estimation. [source] Analytical Methods for Transient Flow to a Well in a Confined-Unconfined AquiferGROUND WATER, Issue 4 2008Li-Tang Hu Concurrent existence of confined and unconfined zones of an aquifer can arise owing to ground water withdrawal by pumping. Using Girinskii's potential function, Chen (1974, 1983) developed an approximate analytical solution to analyze transient ground water flow to a pumping well in an aquifer that changes from an initially confined system to a system with both unconfined and confined regimes. This article presents the details of the Chen model and then compares it with the analytical model developed by Moench and Prickett (1972) for the same problem. Hypothetical pumping test examples in which the aquifer undergoes conversion from confined to water table conditions are solved by the two analytical models and also a numerical model based on MODFLOW. Comparison of the results suggests that the solutions of the Chen model give better results than the Moench and Prickett model except when the radial distance is very large or aquifer thickness is large compared with drawdown. [source] Human genome variation and pharmacogenetics,HUMAN MUTATION, Issue 4 2008Bruce Gottlieb Abstract A recent HGVS-sponsored symposium has examined, for the first time, the possible effects of the discovery of very large and widespread amounts of human genome variation on the emerging fields of pharmacogenetics and pharmacogenomics. This article discusses the effects of the resultant paradigm shifts and raises a number of important questions that need to be considered in order to truly advance the field in a meaningful and significant way. Hum Mutat 29(4):453,455, 2008. © 2008 Wiley-Liss, Inc. [source] Ten novel mutations in the human neurofibromatosis type 1 (NF1) gene in Italian patientsHUMAN MUTATION, Issue 1 2002Paola Origone Abstract The entire NF1 coding region was analyzed for mutations in a panel of 108 unrelated Italian NF1 patients. Using PTT, SSCP, and DNA sequencing, we found 10 mutations which have never been reported before. Clinical diagnosis of NF1 was established according to the NIH consensus criteria in 100 individuals, while 8 were young children with only multiple cafè-au-lait spots. We detected 46 truncated fragments, and 24 of them were fully characterized by SSCP and direct sequencing. Of the 24, 14 were known mutations (R304X, R681X, Q682X, R1306X, R1362X, R1513X, R1748X, Q1794X, R1947X, Y2264X, R2237X, 2674delA, 6789delTTAC, 2027insC). The other 10 mutations represent novel changes that contribute to the germline mutational spectrum of the NF1 gene (K810X, Q2595X, 6772delT, 7190delCT, 7331delA, 1021insTT, 3921insT, 4106insTA, 7149insC, 2033insCG / 2034delA). PTT in a large number of Italian NF1 patients supports the usefulness of this method for characterization of mutations in disorders where the responsible gene is very large and the disease-causing mutations often create a stop codon. In agreement with previous reports, no mutational hotspots within the NF1 gene were detected. © 2002 Wiley-Liss, Inc. [source] Tectonic control of erosion and sedimentation in the Amazon Basin of BoliviaHYDROLOGICAL PROCESSES, Issue 22 2009Patrice Baby Abstract The western Amazon drainage basin, which extends from southern Colombia to northern Bolivia, comprises the Cordillera Oriental of the Andes and its adjacent foreland basin system. In northern Bolivia, the orogenic wedge of the eastern Andes is very large, and its forward propagation controls the morphology of the Madeira drainage basin. We consider here the erosion and sedimentation mass balance in this part of the Amazon Basin, estimated on the basis of recent sediment yield data, within the current tectonic and geomorphic framework. The total suspended sediment (TSS) flux exported from the present orogenic wedge of northern Bolivia has been estimated at 500,600 million t year,1. More than 50% of the total sediment load crossing the Madeira foreland basin system is deposited. The rest of the sediments (less than 46%) reaches the eastern Amazon Basin, bypassing the Brazilian craton to the north. The average mass of sediment that has been deposited from the late Miocene to the present in the Madeira foreland basin sedimentation system is less than that intercepted today, by a factor of about 2·4. These results can be interpreted as an increase in Bolivian foreland basin flexural subsidence over time, associated with crust thickening and orogenic loading, and accentuated by the growing mass of retained sediments. They are consistent with the uplift rates of the Cordillera Oriental, obtained from fission-track dating, which began increasing significantly around 10,15 Ma. Copyright © 2009 John Wiley & Sons, Ltd. [source] Hydrometeorological behaviour of pine and larch forests in eastern SiberiaHYDROLOGICAL PROCESSES, Issue 1 2004Shuko Hamada Abstract Seasonal changes in the water and energy exchanges over a pine forest in eastern Siberia were investigated and compared with published data from a nearby larch forest. Continuous observations (April to August 2000) were made of the eddy-correlation sensible heat flux and latent heat flux above the canopy. The energy balance was almost closed, although the sum of the turbulent fluxes sometimes exceeded the available energy flux (Rn , G) when the latent heat flux was large; this was related to the wind direction. We examined the seasonal variation in energy balance components at this site. The seasonal variation and magnitude of the sensible heat flux (H) was similar to that of the latent heat flux (,E), with maximum values occurring in mid-June. Consequently, the Bowen ratio was around 1·0 on many days during the study period. On some clear days just after rainfall, ,E was very large and the sum of H and ,E exceeded Rn , G. The evapotranspiration rate above the dry canopy from May to August was 2·2 mm day,1. The contributions of understory evapotranspiration (Eu) and overstory transpiration (Eo) to the evapotranspiration of the entire ecosystem (Et) were both from 25 to 50% throughout the period analysed. These results suggest that Eu plays a very important role in the water cycle at this site. From snowmelt through the tree growth season (23 April to 19 August 2000), the total incoming water, comprised of the sum of precipitation and the water equivalent of the snow at the beginning of the melt season, was 228 mm. Total evapotranspiration from the forest, including interception loss and evaporation from the soil when the canopy was wet, was 208,254 mm. The difference between the incoming and outgoing amounts in the water balance was from +20 to ,26 mm. The water and energy exchanges of the pine and larch forest differed in that ,E and H increased slowly in the pine forest, whereas ,E increased rapidly in the larch forest and H decreased sharply after the melting season. Consequently, the shape of the Bowen ratio curves at the two sites differed over the period analysed, as a result of the differences in the species in each forest and in soil thawing. Copyright © 2003 John Wiley & Sons, Ltd. [source] An efficient diagonal preconditioner for finite element solution of Biot's consolidation equationsINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 4 2002K. K. Phoon Abstract Finite element simulations of very large-scale soil,structure interaction problems (e.g. excavations, tunnelling, pile-rafts, etc.) typically involve the solution of a very large, ill-conditioned, and indefinite Biot system of equations. The traditional preconditioned conjugate gradient solver coupled with the standard Jacobi (SJ) preconditioner can be very inefficient for this class of problems. This paper presents a robust generalized Jacobi (GJ) preconditioner that is extremely effective for solving very large-scale Biot's finite element equations using the symmetric quasi-minimal residual method. The GJ preconditioner can be formed, inverted, and implemented within an ,element-by-element' framework as readily as the SJ preconditioner. It was derived as a diagonal approximation to a theoretical form, which can be proven mathematically to possess an attractive eigenvalue clustering property. The effectiveness of the GJ preconditioner over a wide range of soil stiffness and permeability was demonstrated numerically using a simple three-dimensional footing problem. This paper casts a new perspective on the potentialities of the simple diagonal preconditioner, which has been commonly perceived as being useful only in situations where it can serve as an approximate inverse to a diagonally dominant coefficient matrix. Copyright © 2002 John Wiley & Sons, Ltd. [source] The p -version of the finite element method for three-dimensional curved thin walled structuresINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 7 2001A. Düster Abstract In this paper we present an implementation of a three-dimensional p -version for structural problems of solids with almost arbitrarily curved surfaces. Applying the blending function method, complex structures can often be modelled by a few p -elements, being the basis for a higher order approximation. Numerical examples will demonstrate, that the p -version with anisotropic Ansatz spaces allows to predict the structural behaviour of three-dimensional plates and shells with approximately the same amount of degrees of freedom as in the two-dimensional case, yet significantly more accurate due to the three-dimensional model. Furthermore, it is advantageous to compute complex structures exclusively with three-dimensional discretizations as no special elements are needed to model the transition from dimensionally reduced formulations like plates or shells to fully three-dimensional solid elements. Using the p -version with anisotropic Ansatz spaces the whole structure can be efficiently discretized with solid elements, even if the aspect ratio of the elements becomes very large. Copyright © 2001 John Wiley Sons, Ltd. [source] Atypical X-linked ichthyosis in a patient with a large deletion involving the steroid sulfatase (STS) geneINTERNATIONAL JOURNAL OF DERMATOLOGY, Issue 2 2009Luz Gonzalez-Huerta MD A 70-year-old male presented with very large, thick, tightly adherent, dark-brown scales on the front of his lower extremities. His face, neck, back, abdomen, upper extremities, flexural areas, palms and soles as well as hair and nails were not involved. Family history was negative for similar lesions. Otherwise, the patient had a normal development. Onset of symptoms occurred during childhood with scales on lower extremities with no more additional features. Treatment included emollients exclusively with partial and temporary remission of cutaneous lesions. Recently, the patient had not received topical or systemic medical treatment. Laboratory investigations were within normal limits. The patient had undetectable levels of STS activity when compared with normal control (0.00 pmol mg -1 protein h -1) which confirmed the diagnosis of X-linked ichthyosis (XLI) . PCR analysis showed deletion of the STS gene, markers DXS1139 and DXF22S1and the 5, end of the VCX3A gene. The patient had scales present on lower extremities only with no medical treatment that corresponded to an unusual clinical manifestation of XLI. Clinical manifestations of XLI are due to a great variety of environmental, genetic and individual factors that should be considered in XLI diagnosis. [source] Selective sampling for approximate clustering of very large data setsINTERNATIONAL JOURNAL OF INTELLIGENT SYSTEMS, Issue 3 2008Liang Wang A key challenge in pattern recognition is how to scale the computational efficiency of clustering algorithms on large data sets. The extension of non-Euclidean relational fuzzy c-means (NERF) clustering to very large (VL = unloadable) relational data is called the extended NERF (eNERF) clustering algorithm, which comprises four phases: (i) finding distinguished features that monitor progressive sampling; (ii) progressively sampling from a N × N relational matrix RN to obtain a n × n sample matrix Rn; (iii) clustering Rn with literal NERF; and (iv) extending the clusters in Rn to the remainder of the relational data. Previously published examples on several fairly small data sets suggest that eNERF is feasible for truly large data sets. However, it seems that phases (i) and (ii), i.e., finding Rn, are not very practical because the sample size n often turns out to be roughly 50% of n, and this over-sampling defeats the whole purpose of eNERF. In this paper, we examine the performance of the sampling scheme of eNERF with respect to different parameters. We propose a modified sampling scheme for use with eNERF that combines simple random sampling with (parts of) the sampling procedures used by eNERF and a related algorithm sVAT (scalable visual assessment of clustering tendency). We demonstrate that our modified sampling scheme can eliminate over-sampling of the original progressive sampling scheme, thus enabling the processing of truly VL data. Numerical experiments on a distance matrix of a set of 3,000,000 vectors drawn from a mixture of 5 bivariate normal distributions demonstrate the feasibility and effectiveness of the proposed sampling method. We also find that actually running eNERF on a data set of this size is very costly in terms of computation time. Thus, our results demonstrate that further modification of eNERF, especially the extension stage, will be needed before it is truly practical for VL data. © 2008 Wiley Periodicals, Inc. [source] Mining interesting sequential patterns for intelligent systemsINTERNATIONAL JOURNAL OF INTELLIGENT SYSTEMS, Issue 1 2005Show-Jane Yen Mining sequential patterns means to discover sequential purchasing behaviors of most customers from a large number of customer transactions. Past transaction data can be analyzed to discover customer purchasing behaviors such that the quality of business decisions can be improved. However, the size of the transaction database can be very large. It is very time consuming to find all the sequential patterns from a large database, and users may be only interested in some sequential patterns. Moreover, the criteria of the discovered sequential patterns for user requirements may not be the same. Many uninteresting sequential patterns for user requirements can be generated when traditional mining methods are applied. Hence, a data mining language needs to be provided such that users can query only knowledge of interest to them from a large database of customer transactions. In this article, a data mining language is presented. From the data mining language, users can specify the items of interest and the criteria of the sequential patterns to be discovered. Also, an efficient data mining technique is proposed to extract the sequential patterns according to the users' requests. © 2005 Wiley Periodicals, Inc. Int J Int Syst 20: 73,87, 2005. [source] Size matters sometimes: wall height and the structure of subtidal benthic invertebrate assemblages in south-eastern Australia and Mediterranean SpainJOURNAL OF BIOGEOGRAPHY, Issue 12 2003A. R. Davis Abstract Aim, Variation in the structure of shallow subtidal invertebrate assemblages was examined over three spatial scales; within reef, between reef and between continents. We sought to provide a context from which to examine and interpret ecological processes between continents. In addition, we predicted that variation in pattern would increase as the scale of examination increased. Location, Reefs near Wollongong and within Jervis Bay in south-eastern Australia and Mediterranean reefs on the Costa Brava (Catalonia), north-eastern Spain. Methods, We compared assemblages on vertical rock walls of two heights , short (< 2 m) and tall (> 3 m) in two temperate regions over the same depth range. Specifically we examined the diversity and cover of invertebrates, the cover and biomass of foliose and crustose algae, the size of invertebrate colonies and the biomass of urchins on short and tall walls (n = 3) at each of two locations in each country. Results, Foliose algae dominated rock walls in Spain and although invertebrate cover was high, colonies were generally very small. Two urchin species were commonly encountered on rock walls in Spain, Arbacia lixula and Paracentrotus lividus; their biomass was relatively low and did not differ significantly between short and tall walls. These findings contrasted strongly with south-eastern Australia, where foliose algae were almost completely absent. A single urchin species, Centrostephanus rodgersii occurred with extremely high biomass on short walls, which were dominated by grazer-resistant crustose calcareous algae. In contrast, the biomass of this urchin was low on tall walls, which were dominated by invertebrates, usually exceeding 95% in cover. Invertebrate colonies were significantly larger on both short and tall walls in south-eastern Australia relative to the Mediterranean. Findings within a country were consistent between the replicate rock walls and between locations. In contrast to our prediction, however, there was significant variation among walls within a location, but not among locations within a continent. Temporal variation in the structure of these assemblages was not examined, but appears limited. Main conclusions, We conclude that submarine topography, i.e. the presence of short or tall rock walls, as a function of rock type and structure, has a marked impact on community structure in south-eastern Australia, but made little difference to the structure of the assemblage in Mediterranean Spain. The differences in structure we observed between walls of different heights in Australia were correlated with differences in the biomass of urchins and they appear to be major determinants of assemblage structure. Interactions among species are often reported from disparate parts of the globe with little or no reference to the structure of the assemblage of which they are a part; we contend that this will hinder interpretation. Our data are consistent with the organisms in these two regions experiencing distinct selection pressures; for example high levels of urchin grazing activity in south-eastern Australia, and shading and whiplash associated with an algal canopy in the Mediterranean. It may not be appropriate to contrast processes operating at very large (intercontinental) scales unless context can be established with a clear understanding of ecological pattern. Objectivos, En el presente trabajo hemos examinado la variación en estructura de comunidades de invertebrados de aguas someras a tres escalas espaciales: dentro de arrecifes rocosos, entre arrecifes y entre continentes. Nuestro objetivo era proveer un contexto para examinar y interpretar procesos ecológicos entre continentes. Además, realizamos la predicción de que el modelo de variación aumentaría conforme aumentaba la escala de observación. Localidad, Arrecifes rocosos cerca de Wollongong y en Jarvis Bay en la zona sudeste de Australia y arrecifes rocosos mediterráneos en la Costa Brava (Cataluña), en el nordeste de España. Metodos, Comparamos comunidades en paredes rocosas verticales de dos alturas , bajas (< 2 m) y altas (> 3 m) en dos regiones templadas y dentro del mismo rango de profundidades. Específicamente, examinamos la diversidad y el recubrimiento de invertebrados, el recubrimiento y la biomasa de algas foliosas e incrustantes, la medida de las colonias de invertebrados y la biomasa de erizos en paredes bajas y altas (n = 3) en dos localidades de cada país. Resultados, Las algas foliosas dominaban las paredes rocosas en España y, aunque el recubrimiento de invertebrados era alto, las colonias eran generalmente muy pequeñas. Dos especies de erizos eran comunes en las paredes rocosas en España: Arbacia lixula y Paracentrotus lividus. Su biomasa total era relativamente pequeña y no mostraba diferencias significativas entre paredes bajas y altas. Estos resultados contrastan con los hallados en el sudeste de Australia, donde las algas foliosas eran prácticamente ausentes. Una única especie de erizo, Centrostephanus rodgersii, se encontraba en las paredes bajas, donde presentaba elevadas biomasas. Estas paredes estaban dominadas por algas incrustantes y carbonatadas resistentes al ramoneo por erizos. En cambio, la biomasa de este erizo era baja en paredes altas, que estaban dominadas por invertebrados, con recubrimientos normalmente por encima del 95%. Las colonias de invertebrados eran significativamente más grandes tanto en las paredes altas como bajas en el sudeste de Australia en comparación con el Mediterráneo. Los resultados dentro de cada país eran consistentes entre las réplicas de paredes estudiadas y entre localidades. Contrariamente a nuestra predicción, sin embargo, había una variación significativa entre paredes dentro de una localidad pero no entre localidades dentro de un continente. La variación temporal en estructura en estas comunidades no fue estudiada, pero parece ser limitada. Conclusiones Principales, Concluimos que la topografía submarina, esto es, la presencia de paredes bajas o altas en función del tipo de roca y estructura, tiene un efecto importante en la estructura de las comunidades en el sudeste de Australia. Este factor, sin embargo, tiene un efecto muy limitado en el Mediterráneo español. Las diferencias en estructura observadas entre paredes de diferentes alturas en Australia se correlacionan con diferencias en la biomasa de erizos, los cuales parecen ser determinantes en la estructura de las comunidades. Frecuentemente se estudian interacciones entre especies en zonas alejadas del globo con escasa o nula referencia a la estructura de la comunidad de la que forman parte. En nuestra opinión este hecho impide una correcta interpretación. Nuestros datos son consistentes con la idea de que los organismos en las dos regiones estudiadas experimentan diversas presiones selectivas, por ejemplo, niveles altos de ramoneo por erizos en el sudeste de Australia, y oscurecimiento y disturbancia mecánica asociadas a la cobertura de algas en el Mediterráneo. No parece apropiado comparar procesos que operan a escalas muy amplias (intercontinentales) sin establecer antes un contexto con una comprensión clara de los parámetros ecológicos. [source] Accelerating the analyses of 3-way and 4-way PARAFAC models utilizing multi-dimensional wavelet compressionJOURNAL OF CHEMOMETRICS, Issue 11-12 2005Jeff Cramer Abstract Parallel factor analysis (PARAFAC) is one of the most popular methods for evaluating multi-way data sets, such as those typically acquired by hyphenated measurement techniques. One of the reasons for PARAFAC popularity is the ability to extract directly interpretable chemometric models with little a priori information and the capability to handle unknown interferents and missing values. However, PARAFAC requires long computation times that often prohibit sufficiently fast analyses for applications such as online sensing. An additional challenge faced by PARAFAC users is the handling and storage of very large, high-dimensional data sets. Accelerating computations and reducing storage requirements in multi-way analyses are the topics of this manuscript. This study introduces a data pre-processing method based on multi-dimensional wavelet transforms (WTs), which enables highly efficient data compression applied prior to data evaluation. Because multi-dimensional WTs are linear, the intrinsic underlying linear data construction is preserved in the wavelet domain. In almost all studied examples, computation times for analyzing the much smaller, compressed data sets could be reduced so much that the additional effort for wavelet compression was more than recompensated. For 3-way and 4-way synthetic and experimental data sets, acceleration factors up to 50 have been achieved; these data sets could be compressed down to a few per cent of the original size. Despite the high compression, accurate and interpretable models were derived, which are in good agreement with conventionally determined PARAFAC models. This study also found that the wavelet type used for compression is an important factor determining acceleration factors, data compression ratios and model quality. Copyright © 2006 John Wiley & Sons, Ltd. [source] Electrostatic energies and forces computed without explicit interparticle interactions: A linear time complexity formulationJOURNAL OF COMPUTATIONAL CHEMISTRY, Issue 8 2005Robert J. Petrella Abstract A rapid method for the calculation of the electrostatic energy of a system without a cutoff is described in which the computational time grows linearly with the number of particles or charges. The inverse of the distance is approximated as a polynomial, which is then transformed into a function whose terms involve individual particles, instead of particle pairs, by a partitioning of the double sum. In this way, the electrostatic energy that is determined by the interparticle interactions is obtained without explicit calculation of these interactions. For systems of positive charges positioned on a face-centered cubic lattice, the calculation of the energy by the new method is shown to be faster than the calculation of the exact energy, in many cases by an order of magnitude, and to be accurate to within 1,2%. The application of this method to increase the accuracy of conventional truncation-based calculations in condensed-phase systems is also demonstrated by combining the approximated long-range electrostatic interactions with the exact short-range interactions in a "hybrid" calculation. For a 20-Å sphere of water molecules, the forces are shown to be six times as accurate using this hybrid method as those calculated with conventional truncation of the electrostatic energy function at 12 Å. This is accomplished with a slight increase in speed, and with a sevenfold increase in speed relative to the exact all-pair calculation. Structures minimized with the hybrid function are shown to be closer to structures minimized with an exact all-pair electrostatic energy function than are those minimized with a conventional 13-Å cutoff-based electrostatic energy function. Comparison of the energies and forces calculated with the exact method illustrate that the absolute errors obtained with standard truncation can be very large. The extension of the current method to other pairwise functions as well as to multibody functions, is described. © 2005 Wiley Periodicals, Inc. J Comput Chem 26: 755,787, 2005 [source] The evolution of self-fertilization and inbreeding depression under pollen discounting and pollen limitationJOURNAL OF EVOLUTIONARY BIOLOGY, Issue 3 2005E. PORCHER Abstract We model the evolution of plant mating systems under the joint effects of pollen discounting and pollen limitation, using a dynamic model of inbreeding depression, allowing for partial purging of recessive lethal mutations by selfing. Stable mixed mating systems occur for a wide range of parameter values with pollen discounting alone. However, when typical levels of pollen limitation are combined with pollen discounting, stable selfing rates are always high but less than 1 (0.9 < s < 1 in most cases); in this situation, complete selfing does not evolve because pollen discounting becomes very large at high selfing rates, so that the automatic advantage of selfing changes to a disadvantage. These results suggest that mixed mating systems with high selfing rates can be maintained by selection, whereas mixed mating systems with low to moderate selfing rates are more likely attributable to unavoidable geitonogamous selfing. [source] Spatially structured genetic variation in a broadcast spawning bivalve: quantitative vs. molecular traitsJOURNAL OF EVOLUTIONARY BIOLOGY, Issue 2 2003P. C. Luttikhuizen Abstract Understanding the origin, maintenance and significance of phenotypic variation is one of the central issues in evolutionary biology. An ongoing discussion focuses on the relative roles of isolation and selection as being at the heart of genetically based spatial variation. We address this issue in a representative of a taxon group in which isolation is unlikely: a marine broadcast spawning invertebrate. During the free-swimming larval phase, dispersal is potentially very large. For such taxa, small-scale population genetic structuring in neutral molecular markers tends to be limited, conform expectations. Small-scale differentiation of selective traits is expected to be hindered by the putatively high gene flow. We determined the geographical distribution of molecular markers and of variation in a shell shape measure, globosity, for the bivalve Macoma balthica (L.) in the western Dutch Wadden Sea and adjacent North Sea in three subsequent years, and found that shells of this clam are more globose in the Wadden Sea. By rearing clams in a common garden in the laboratory starting from the gamete phase, we show that the ecotypes are genetically different; heritability is estimated at 23%. The proportion of total genetic variation that is between sites is much larger for the morphological additive genetic variation (QST = 0.416) than for allozyme (FST = 0.000,0.022) and mitochondrial DNA cytochrome- c -oxidase-1 sequence variation (,ST = 0.017). Divergent selection must be involved and intraspecific spatial genetic differentiation in marine broadcast spawners is apparently not constrained by low levels of isolation. [source] Scaled Gromov hyperbolic graphsJOURNAL OF GRAPH THEORY, Issue 2 2008Edmond Jonckheere Abstract In this article, the ,-hyperbolic concept, originally developed for infinite graphs, is adapted to very large but finite graphs. Such graphs can indeed exhibit properties typical of negatively curved spaces, yet the traditional ,-hyperbolic concept, which requires existence of an upper bound on the fatness , of the geodesic triangles, is unable to capture those properties, as any finite graph has finite ,. Here the idea is to scale , relative to the diameter of the geodesic triangles and use the Cartan,Alexandrov,Toponogov (CAT) theory to derive the thresholding value of ,diam below which the geometry has negative curvature properties. © 2007 Wiley Periodicals, Inc. J Graph Theory 57: 157,180, 2008 [source] Novel variants related to TT virus distributed widely in China,JOURNAL OF MEDICAL VIROLOGY, Issue 1 2002Kangxian Luo Abstract TTV is a DNA virus with high genetic heterogeneity. To investigate the novel isolates of the virus, blood samples were collected from subjects who lived in various parts of China and suffered from hepatitis or were asymptomatic carriers. Nested PCR was carried out to amplify a 3.2-kb fragment using primers deduced from the prototype TTV (TA278). The ten entire 3.2-kb nt sequences were aligned with isolate TA278, SANBAN, TUS01, and SENV retrieved from GenBank, and a phylogenetic tree was constructed by Neighbor-Joining method. The analysis indicated that five novel variants of the present study have not been described before, and all TTV-related isolates could be classified into three groups. The isolate TCHN-A, B and TUS01 were included in a group, and the remaining novel isolates together with SANBAN and TA278 clustered into another group, while SEN virus formed a distinct group. The genetic distances of the five novel variants were 0.5507,0.8476 to TA278, 0.4635,0.7877 to SANBAN, 0.6064,0.7834 to TUS01 and 0.6936,0.8236 to SENV. Of these novel variants, the ORF1 consisted of 426,772 aa and ORF2 of 141,156 aa. The nt identities of ORF1 and ORF2 between those variants and TA278, SANBAN, and TUS01 were 46.1,60.8 and 48.7,63.6%, and those of aa sequences were only 27.1,52.4 and 28.9,45.5%, respectively. The first 65 aa of ORF1 were rich in arginine and most conserved with homology of 56.5,70.0%. There was a hypervariable region from aa 286 to 403 with merely 17.7,27.0% of identity. Despite a low aa identity between TA278 and the variants, they have similar hydrophilicity profiles of ORF1. There were 2,10 N-glycosylation motifs found in these variants. In conclusion, despite the high divergence, sequences of all these isolates shared common genome organisation, ORF structure, hydrophilicity patterns, and some potential motifs with TTV prototype. It is suggested that various TTV and TTV-related isolates belong to a very large and complex family, which remains to be studied. J. Med. Virol. 67:118,126, 2002. © 2002 Wiley-Liss, Inc. [source] Comparison of the three-dimensional structures of a human Bence-Jones dimer crystallized on Earth and aboard US Space Shuttle Mission STS-95,JOURNAL OF MOLECULAR RECOGNITION, Issue 2 2003Simon S. Terzyan Abstract Crystals of a human (Sea) Bence-Jones dimer were produced in a capillary by vapor diffusion under microgravity conditions in the 9 day US Space Shuttle Mission STS-95. In comparison to ground-based experiments, nucleation was facile and spontaneous in space. Appearance of a very large (8,×,1.6,×,1.0,mm) crystal in a short time period is a strong endorsement for the use of microgravity to produce crystals sufficiently large for neutron diffraction studies. The Sea dimer crystallized in the orthorhombic space group P212121, with a,=,48.9,Å, b,=,85.2,Å, and c,=,114.0,Å. The crystals grown in microgravity exhibited significantly lower mosaicities than those of ground-based crystals and the X-ray diffraction data had a lower overall B factor. Three-dimensional structures determined by X-ray analysis at two temperatures (100 and 293,K) were indistinguishable from those obtained from ground-based crystals. However, both the crystallographic R factor and the free R factor were slightly lower in the models derived from crystals produced in microgravity. The major difference between the two crystal growth systems is a lack of convection and sedimentation in a microgravity environment. This environment resulted in the growth of much larger, higher-quality crystals of the Sea Bence-Jones protein. Structurally, heretofore unrecognized grooves on the external surfaces of the Sea and other immunoglobulin-derived fragments are regular features and may offer supplementary binding regions for super antigens and other elongated ligands in the bloodstream and perivascular tissues. Copyright © 2003 John Wiley & Sons, Ltd. [source] Do dendritic amphiphiles self-assemble in water?JOURNAL OF PHYSICAL ORGANIC CHEMISTRY, Issue 7 2001A Fourier transform pulse-gradient spin-echo NMR study Abstract Amphiphilic poly(amidoamine) (PAMAM) dendrimers were synthesized having an average of 7,46 hydrophobic chains of varying lengths (C10,C14) attached to the periphery of 64 amine groups. The synthesis was performed in three steps: (1) protection of a desired number of amines with BOC groups; (2) reaction of the remaining amine groups with long-chain acid chlorides; and (3) deprotection from the BOC groups to produce the amphiphilic dendrimers as HCl salts. The behavior of the dendrimers in aqueous media was examined by pulse-gradient spin-echo (FT-PGSE) NMR and dynamic light scattering. Self-diffusion data on dendrimers with 22 or fewer chains, along with dynamic light scattering on concentrations of ,16 wt%, gave no indication of dendrimer,dendrimer self-assembly via hydrocarbon chains exposed on the dendrimer surface. It is concluded that dendrimers with 7,22 chains, each having 10,14 carbons, behave as unimolecular entities with chains coiled largely within the dendrimer periphery. Only when the number of chains becomes very large (ca ,34) are chains forced externally where they can promote hydrophobically induced self-assembly. Monomeric dendrimers possessing the full range of functional polarity have great potential in enzyme modeling. Copyright © 2001 John Wiley & Sons, Ltd. [source] | |||||||||||||||||||||||||||||||||||||||||||||||||