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Circular
Terms modified by Circular Selected AbstractsMetal-Assisted Hybridization of Oligonucleotides, Evaluation of Circular 2,- O -Me RNA as Ligands for the TAR RNA TargetEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 6 2003Laurence Zapata Abstract Two complementary oligonucleotides were conjugated with terpyridine ligands at their nearby 5,- and 3,-ends. Addition of a stoichiometric amount of a transition metal (Zn2+, Fe2+) resulted in a large increase in the melting temperature of the duplex. The conjugation of TPY to stem-loop oligomers provided an efficient procedure for the cyclisation of the oligomer after the addition of metal ions. Such a short stem-loop oligomer was designed to target the HIV-1 TAR RNA through loop,loop interactions. The addition of Zn2+ ions yielded a good ligand (Kd = 30 nM) for this RNA structural element. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003) [source] Can a purchaser be a partner? nursing education in the English universitiesINTERNATIONAL JOURNAL OF HEALTH PLANNING AND MANAGEMENT, Issue 2 2001E. Meerabeau Abstract Since the early 1990s, public sector management in England has been exhorted to follow the example of the private sector, and ,quasi-markets' have been established, for example in the health service. A quasi-market also exists between the NHS and higher education for the purchasing (or procurement) of nursing education. This paper uses policy documents such as the National Health Service Executive Circular (March 1999) on ,Good Contracting Guidelines' for Non-Medical Education and Training, plus other relevant literature on the commodification of higher education, quasi-markets and contract theory to examine this market, and the confusion of two rhetorics, those of competition and partnership. Nursing occupies a marginal place in higher education in England, having only recently become part of it. The emphasis of the quasi-market on the output of a trained ,fit for purpose' labour force combines with professional attempts to create an academic discipline, in complex ways which are as yet underanalysed. Copyright © 2001 John Wiley & Sons, Ltd. [source] Cognitive mediation of panic reduction during an early intervention for panicACTA PSYCHIATRICA SCANDINAVICA, Issue 1 2010P. Meulenbeek Meulenbeek P, Spinhoven P, Smit F, van Balkom A, Cuijpers P. Cognitive mediation of panic reduction during an early intervention for panic. Objective:, This study investigated cognitive mediation of improvement in panic disorder (PD) symptomatology during and after an early intervention for panic symptoms in subthreshold and mild PD. Method:, We executed a pragmatic, pre-post, two-group, multi-site, randomized trial of an early intervention for panic symptoms, based on cognitive-behavioural therapy, vs. a wait-list control group in a sample of 217 participants with subthreshold PD or mild PD. Results:, First, two of the three subscales of the mediator variable Panic Appraisal Inventory (PAI-anticipation and PAI-coping) significantly mediated residual change in PD symptomatology on the PD Severity Scale-Self Report. Second, preintervention to postintervention PAI-anticipation and PAI-coping change scores significantly predicted postintervention to follow-up change in PD symptomatology after controlling for other change scores. However, the converse association was also significant. Conclusion:, The results suggest that changes in cognitions may mediate changes in PD symptomatology and that the process of change is circular. [source] Particle capture in ciliary filter-feeding gymnolaemate and phylactolaemate bryozoans , a comparative studyACTA ZOOLOGICA, Issue 4 2010Hans Ulrik Riisgård Abstract Riisgård, H.U., Okamura, B. and Funch, P. 2009. Particle capture in ciliary filter-feeding gymnolaemate and phylactolaemate bryozoans , a comparative study. ,Acta Zoologica (Stockholm) 91: 416,425. We studied particle capture using video-microscopy in two gymnolaemates, the marine cheilostome Electra pilosa and the freshwater ctenostome Paludicella articulata, and three phylactolaemates, Fredericella sultana with a circular funnel-shaped lophophore, and Cristatella mucedo and Lophophus crystallinus, both with a horseshoe-shaped lophophore. The video-microscope observations along with studies of lophophore morphology and ultrastructure indicated that phylactolaemate and gymnolaemate bryozoans with a diversity of lophophore shapes rely on the same basic structures and mechanisms for particle capture. Our study also demonstrates that essential features of the particle capture process resemble one another in bryozoans, brachiopods and phoronids. [source] THE TECHNICAL FUNDAMENTALS OF ENDOSCOPIC MUCOSAL RESECTION IN THE COLON: OUR METHODDIGESTIVE ENDOSCOPY, Issue 2004Yasushi Oda ABSTRACT Endoscopic mucosal resection (EMR) is the technique used to resect flat or depressed tumors or larger tumors such as laterally spreading tumors with marginal normal mucosa. Recently, endoscopic mucosal dissection technique has been rapidly accepted, mainly in early gastric cancer in Japan. We need to have firm knowledge of EMR technique in the colon for recovery as we advance this new technique. We describe our conventional EMR method practically. EMR should be performed to locate the target lesion at down side to perform sure EMR. The ideal shape of upheaval by saline injection is hemisphere. The needle sheath and snare should be taken out a little of the endoscopy to manipulate firmly. Another technique of secure EMR is the snare manipulation. We prefer that the shape of the snare is circular and the snare is hard. It is important while trapping to press the target lesion with both the whole snare circle and the end of the sheath. With these fundamental procedures we could resect the target lesions at will. [source] The musculature of three species of gastrotrichs surveyed with confocal laser scanning microscopy (CLSM)ACTA ZOOLOGICA, Issue 3 2006Francesca Leasi Abstract The muscular system of gastrotrichs consists of circular, longitudinal and helicoidal bands that when analysed with confocal laser scanning microscopy, provide new insights into their functional organization and phylogenetic importance. We therefore undertook a comparative study of the muscle organization in three species of Gastrotricha from the orders Macrodasyida (Paradasys sp., Lepidodasyidae; Turbanella sp., Turbanellidae) and Chaetonotida (Polymerurus nodicaudus, Chaetonotidae). The general muscle organization of the marine interstitial macrodasyidans, Paradasys and Turbanella, not only confirms earlier observation on other species but also adds new details concerning the organization and number of helicoidal, longitudinal and other muscle bands (e.g. semicircular band). The freshwater, epibenthic,epiphytic chaetonotid, Polymerurus nodicaudus, has a similar muscular organization to other species of Chaetonotidae, especially species of Chaetonotus, Halichaetonotus and Lepidodermella. Perhaps unique to Polymerurus is the combined presence of an unbranched Rückenhautmuskel (also in Halichaetonotus and Lepidodermella) and a specialized dorsoventral caudal muscle, which flank the splanchnic component of the longitudinal muscles (only in Chaetonotus and Lepidodermella). This combination, together with the presence of splanchnic dorsoventral muscles, known only in Xenotrichulidae, implies a unique phylogenetic position for Polymerurus, and indicates a potential basal position of this taxon among the Chaetonotidae studied so far (i.e. Aspidiophorus, Chaetonotus, Halichaetonotus and Lepidodermella). [source] In Vitro Validation of a New Approach for Quantitating Regurgitations Using Proximal Isovelocity Surface AreaECHOCARDIOGRAPHY, Issue 7 2000A. Delouche The present work has been designed to validate the calculation of the effective regurgitant orifice (ERO) area with the use of a new formula that takes into account the velocity profile (Vr vs r) and that is insensitive to errors in the determination of the position of the orifice. Assuming a hemispheric model, ERO = 2,r2· Vr/Vo (with Vo= velocity at the orifice) and (Vo/Vr)0.5= (2,/ERO)0.5r. Thus, the slope of the corresponding linear regression allows ERO to be calculated as: ERO = 2,/slope2. This approach was tested in vitro in pulsatile conditions on circular, conical, and slit-like orifices. The calculated ERO was compared with the actual jet cross sectional area derived from the transverse velocity profile at the jet origin. For the purpose of comparison, the "classical" ERO was calculated for all the configurations, angulations, and threshold velocities. The relationship between (Vo/Vr)0.5 was linear (r > 0.98) over a wide range of velocities. The nonhemispheric components were found to modify the constant and not the slope. The mean variation of the calculated ERO was 6.5%. The correlation between the calculated and the actual ERO was very close (>0.97) with slope equal to 0.96. By comparison with the new method, the classical formula gave an underestimation of the ERO that dramatically increased when studying the flow closer to the orifice or in the case of error on the measurement of r. In conclusion, a method using velocity profiles instead of isolated values improves the accuracy of the proximal isovelocity surface area (PISA) method for measuring the ERO. [source] Regularity of species richness relationships to patch size and shapeECOGRAPHY, Issue 4 2007Einar Heegaard This study aims to assess the degree of regularity in the effect of patch size and patch shape on plant species richness across a macroscale region, and to evaluate the implications for nature conservation. Our study area covers south-eastern Norway and contains 16 agricultural landscapes with 2162 patches. To analyse regularity a local linear mixed model (LLMM) was applied. This procedure estimates the richness trends due to shared effects of size and shape, and simultaneously provides the landscape-specific random effect. The latter is a direct estimate of the degree of irregularity between the landscapes, conditioned on specific values of size and shape. The results show a positive interaction between the shape and size of patches, which is repeated for all landscapes. The shape of the patches produces more regular patterns in species richness than the size of patches. This we attribute to effects of dispersal and distance to neighbouring patches of different environmentally conditioned species pools. Large and complex patches have shorter average distance to neighbouring patches (of different types) than large simple-shaped (circular) patches have. We attribute the higher species richness of the former, given a similar area, to a higher number of species dispersed from the outside into the more complex plot. For small patches, however, the distance to the edge is short relative to normal dispersal distances, for patches of all shapes. This explains why the positive effect of shape complexity on species richness is stronger for large patches. This interpretation is supported by a strong spatial correlation conditioned on the most complex patches. Theories of dynamics in biodiversity in patchy landscapes must consider shape as a regulator at the same level as size, and both shape and size of patches should be simultaneously taken into account for management planning. [source] Mechanism of DNA damage by cadmium and interplay of antioxidant enzymes and agentsENVIRONMENTAL TOXICOLOGY, Issue 2 2007Veera L. D. Badisa Abstract Cadmium is an environmental toxicant, which causes cancer in different organs. It was found that it damages DNA in the various tissues and cultured cell lines. To investigate the mechanism of DNA damage, we have studied the effect of cadmium-induced DNA damage in plasmid pBR322 DNA, and the possible ameliorative effects of antioxidative agents under in vitro conditions. It was observed that cadmium alone did not cause DNA damage. However, it caused DNA damage in the presence of hydrogen peroxide, in a dose dependent manner, because of production of hydroxyl radicals. Findings from this study show the conversion of covalently closed circular double-stranded pBR 322 DNA to the open circular and linear forms of DNA when treated with 10 ,M cadmium and various concentrations of H2O2. The conversion was due to nicking in DNA strands. The observed rate of DNA strand breakage was dependent on H2O2 concentration, temperature, and time. Metallothionein I failed to prevent cadmium-induced DNA nicking in the presence of H2O2. Of the two antioxidant enzymes (catalase and superoxide dismutase) studied, only catalase conferred significant (50,60%) protection. EDTA and DMSO exhibited protection similar to catalase, while mannitol showed only about 20% protection against DNA damage. Ethyl alcohol failed to ameliorate cadmium-induced DNA strands break. From this study, it is plausible to infer that cadmium in the presence of hydrogen peroxide causes DNA damage probably by the formation of hydroxyl ions. These results may indicate that cadmium in vivo could play a major role in the DNA damage induced by oxidative stress. © 2007 Wiley Periodicals, Inc. Environ Toxicol 22: 144,151, 2007. [source] Increased infiltration of Chlamydophila pneumoniae in the vessel wall of human veins after perfusionEUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 7 2008K. Kupreishvili ABSTRACT Background Several studies have suggested an association between Chlamydophila pneumoniae (Cp) infection and atherosclerosis. A recent study detected Cp DNA in the saphenous vein of 12% of all patients before bypass grafting and in 38% of failed grafts. We used a system in which human veins were perfused with autologous blood under arterial pressure. Materials and methods, Veins were surplus segments of saphenous veins of coronary artery bypass grafting (CABG) patients. Vein grafts were perfused with the blood of the same patient after CABG procedures. Veins were analysed for Cp -specific membrane protein using immunohistochemical and PCR analysis. Veins were analysed before and after perfusion (up to 4 h). The number of Cp positive cells was then quantified in the vein layers. Results Cp protein was detected within macrophages only. In non-perfused veins, Cp was present in the adventitia in 91% of all patients, in the circular (64%) and longitudinal (23%) layer of the media. No positivity was found in the intima. Perfusion subsequently resulted in a significant increase of Cp positive cells within the circular layer of the media that, however, differed strongly between different patients. Cp DNA was not detected by PCR in those specimens. Conclusion Cp protein was present in 91% of veins, but the number of positive cells differed remarkably between patients. Perfusion of veins resulted in increased infiltration of Cp into the circular layer. These results may point to a putative discriminating role of Cp with respect to graft failure between different patients. [source] Two-stage detection of partitioned random CDMAEUROPEAN TRANSACTIONS ON TELECOMMUNICATIONS, Issue 5 2008Lukasz Krzymien Random Code Division Multiple Access (CDMA) with low complexity two-stage joint detection/decoding is considered. A sequence partitioning approach is used for modulation, where every spreading sequence is divided into M sections (partitions) which are interleaved prior to transmission. This setup, called partitioned CDMA, can be understood as a generalisation of (chip) interleave division multiple access (IDMA). An analysis of a low-complexity iterative cancellation receiver is presented for arbitrary received power distributions. It is shown that for equal rate and equal power users the asymptotic performance of partitioned CDMA is equal to the performance of CDMA with optimal a posteriori probability (APP) detection for system loads K/N,<,1.49. Effects of asynchronous signal transmission are quantified for standard pulse shaping filters and it is shown that the signal-to-noise ratios achievable in an asynchronous system are improved with respect to fully synchronous transmission. The effect of unequal received powers is examined and considerable gains in performance are obtained by judicious choices of power distributions. For certain power distribution, partitioned CDMA with iterative detection can achieve arbitrary system loads, that is detection is no longer fundamentally interference limited. The practical near-far resistance of the proposed system is illustrated using an example of a receiver with a circular receive footprint and uniformly distributed transmitters (single cell system). Copyright © 2008 John Wiley & Sons, Ltd. [source] Does History End with Postmodernism?FAMILY PROCESS, Issue 4 2001Toward an Ultramodern Family Therapy Although the end of history has often been announced, human thought continues to renew itself, always incorporating, in each of its stages, important aspects of what has come before. In this sense, neither family therapy in general, nor its more particular postmodern orientations, have led to a radical break with the past. Neither can they claim to have reached a comfortable, definitive position. The subjectivist turn that introduced postmodernism into the systemic model has enriched it with important theoretical and practical elements, such as the critique of a therapist's supposed objectivity, circular and reflexive questioning, or the technique of externalization. This article proposes to take the renewal of systemic family therapy farther by addressing still unresolved issues, such as the role of the individual in relational systems, the place of emotions, or the construction of a relational psychopathology. The term "ultramodern family therapy" is proposed until such time as there is agreement upon a better one. [source] Reconstructing the replication complex of AcMNPVFEBS JOURNAL, Issue 24 2002Kathleen L. Hefferon Baculoviruses are well known for their large, circular, double-stranded DNA genomes. The type member, AcMNPV, is the best characterized and undergoes a succession of early, late and very late gene expression during its infection cycle. The viral genes involved in DNA replication have previously been identified and their products are required for the activation of late gene expression. In this study, we FLAG- and HA-tagged the replication late expression factors of AcMNPV, examined their expression and functional activities by CAT assay and Western blot analysis, and determined their subcellular localization in transfected cells by subcellular fractionation and immunofluorescent microscopy. We found that all replication LEFs with the exception of P143 and P35 resided in the nucleus of transfected cells. We further investigated the interactions among various replication LEFs using both yeast two-hybrid and coprecipitation strategies. A summary of the interactive properties of the replication LEFs is presented and a model for a putative AcMNPV replication complex is offered. [source] Origin of post-Minoan caves and volcaniclastic cave fill, Thera (Santorini), GreeceGEOARCHAEOLOGY: AN INTERNATIONAL JOURNAL, Issue 5 2003Joan M. Ramage The Aegean island of Thera (Santorini) was covered by tephra from its cataclysmic Late Bronze Age (ca. 3600 yr B.P.) eruption. Vertical exposures of the eruptive sequence show secondary, nonvolcanic, circular (in cross section) features composed of stratified sediment. Many are inaccessible from the floors of modern quarries and appear to be caves filled with younger sediment, but show no connection to the land surface. A filled cave was found in the wall of a modern gully outside the modern quarries, and a filled cave was found in a terrace scarp, well above the modern gully. Natural (and probably rapid) incision by gullies into the thick tephra deposit left many locations with lateral access to tephra. Inhabitants from post-Minoan to recent times excavated tephra for materials and buildings, and caves were subsequently filled by sporadic (possibly seasonal) flood events that deposited sediment. These gullies may have provided access for modern tephra removal that isolated the filled caves high on the modern quarry walls. © 2003 Wiley Periodicals, Inc. [source] Numerical simulation of natural convection heat transfer in the open space between two horizontal circular planesHEAT TRANSFER - ASIAN RESEARCH (FORMERLY HEAT TRANSFER-JAPANESE RESEARCH), Issue 6 2001Hideki Tokanai Abstract Numerical simulations were conducted for natural convection heat transfer in a narrow gap between two horizontal plates in air. The lower plate is an infinite plate with a circular heating zone. The upper one is the bottom of a vertical cylinder, which is placed right above the circular heated plate and kept at room temperature. A set of Navier,Stokes equations and an energy equation are analyzed for a variety of combinations of gap clearance and Rayleigh number. The calculated average heat transfer values are shown to be in good agreement with the experimentally obtained ones reported in a previous paper. From the obtained isotherms, streamlines, and local Nusselt numbers, it is found that two types of convection appear in the gap space according to the conditions of Rayleigh number and gap clearance: one is a simple convection due to a single renewal flow which replaces heated air with ambient air and the other is a combined convection due to several vortex flows and a renewal flow. Furthermore, the flow rate of each flow controls the rate of heat transfer from the limited area which is covered by each flow. From this fact, the validity of the previously proposed heat transfer correlation is briefly discussed. © 2001 Scripta Technica, Heat Trans Asian Res, 30(6): 485,502, 2001 [source] Negative Poisson's Ratio Behavior Induced by an Elastic InstabilityADVANCED MATERIALS, Issue 3 2010Katia Bertoldi Negative Poisson's ratio behavior has been uncovered in cellular solids that comprise a solid matrix with a square array of circular voids. The simplicity of the fabrication implies robust behavior, which is relevant over a range of scales. The behavior results from an elastic instability, which induces a pattern transformation and excellent quantitative agreement is found between calculation and experiment. [source] Analytical solutions for a three-invariant Cam clay model subjected to drained loading historiesINTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS, Issue 5 2006Dunja Peri Abstract Analytical solutions are derived for a three-invariant Cam clay model subjected to proportional and circular drained loading histories. The solutions are presented for a specific volume, and volumetric and generalized shear strains. In the case of a proportional loading only straight effective stress paths are considered while in the case of a circular loading the maximum possible change in Lode's angle is ,/3 due to plastic isotropy. Additionally, a concept of deviatoric stiffness is devised and an analytical expression for the generalized hardening modulus is derived. Qualitative and quantitative analyses are carried out in the form of direct comparisons between analytical solutions for drained and undrained loading histories thus offering an improved understanding of the three-invariant model. Copyright © 2006 John Wiley & Sons, Ltd. [source] Semi-analytical far field model for three-dimensional finite-element analysisINTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS, Issue 11 2004James P. Doherty Abstract A challenging computational problem arises when a discrete structure (e.g. foundation) interacts with an unbounded medium (e.g. deep soil deposit), particularly if general loading conditions and non-linear material behaviour is assumed. In this paper, a novel method for dealing with such a problem is formulated by combining conventional three-dimensional finite-elements with the recently developed scaled boundary finite-element method. The scaled boundary finite-element method is a semi-analytical technique based on finite-elements that obtains a symmetric stiffness matrix with respect to degrees of freedom on a discretized boundary. The method is particularly well suited to modelling unbounded domains as analytical solutions are found in a radial co-ordinate direction, but, unlike the boundary-element method, no complex fundamental solution is required. A technique for coupling the stiffness matrix of bounded three-dimensional finite-element domain with the stiffness matrix of the unbounded scaled boundary finite-element domain, which uses a Fourier series to model the variation of displacement in the circumferential direction of the cylindrical co-ordinate system, is described. The accuracy and computational efficiency of the new formulation is demonstrated through the linear elastic analysis of rigid circular and square footings. Copyright © 2004 John Wiley & Sons, Ltd. [source] Influence of particle shape and angularity on the behaviour of granular materials: a numerical analysisINTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS, Issue 14 2003C. Nouguier-Lehon Abstract This paper analyses the influence of grain shape and angularity on the behaviour of granular materials from a two-dimensional analysis by means of a discrete element method (Contact Dynamics). Different shapes of grains have been studied (circular, isotropic polygonal and elongated polygonal shapes) as well as different initial states (density) and directions of loading with respect to the initial fabric. Simulations of biaxial tests clearly show that the behaviour of samples with isotropic particles can be dissociated from that of samples with anisotropic particles. Indeed, for isotropic particles, angularity just tends to strengthen the behaviour of samples and slow down either local or global phenomena. One of the main results concerns the existence of a critical state for isotropic grains characterized by an angle of friction at the critical state, a critical void ratio and also a critical anisotropy. This critical state seems meaningless for elongated grains and the behaviour of samples generated with such particles is highly dependent on the direction of loading with respect to the initial fabric. The study of local variables related to fabric and particle orientation gives more information. In particular, the coincidence of the principal axes of the fabric tensor with those of the stress tensor is sudden for isotropic particles. On the contrary, this process is gradually initiated for elongated particles. Copyright © 2003 John Wiley & Sons, Ltd. [source] Scaled boundary finite-element analysis of a non-homogeneous axisymmetric domain subjected to general loadingINTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS, Issue 10 2003James P. Doherty Abstract The scaled boundary finite-element method is derived for elastostatic problems involving an axisymmetric domain subjected to a general load, using a Fourier series to model the variation of displacement in the circumferential direction of the cylindrical co-ordinate system. The method is particularly well suited to modelling unbounded problems, and the formulation allows a power-law variation of Young's modulus with depth. The efficiency and accuracy of the method is demonstrated through a study showing the convergence of the computed solutions to analytical solutions for the vertical, horizontal, moment and torsion loading of a rigid circular footing on the surface of a homogeneous elastic half-space. Computed solutions for the vertical and moment loading of a smooth rigid circular footing on a non-homogeneous half-space are compared to analytical ones, demonstrating the method's ability to accurately model a variation of Young's modulus with depth. Copyright © 2003 John Wiley & Sons, Ltd. [source] Solution of two-dimensional Poisson problems in quadrilateral domains using transfinite Coons interpolationINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING, Issue 7 2004Christopher G. Provatidis Abstract This paper proposes a global approximation method to solve elliptic boundary value Poisson problems in arbitrary shaped 2-D domains. Using transfinite interpolation, a symmetric finite element formulation is derived for degrees of freedom arranged mostly along the boundary of the domain. In cases where both Dirichlet and Neumann boundary conditions occur, the numerical solution is based on bivariate Coons interpolation using the boundary only. Furthermore, in case of only Dirichlet boundary conditions and no existing axes of symmetry, it is proposed to use at least one internal point and apply transfinite interpolation. The theory is sustained by five numerical examples applied to domains of square, circular and elliptic shape. Copyright © 2004 John Wiley & Sons, Ltd. [source] An appropriate quadrature rule for the analysis of plane crack problems in the boundary-element methodINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING, Issue 10 2001E. E. Theotokoglou Abstract An hypersingular integral equation of a three-dimensional elastic solid with an embedded planar crack subjected to a uniform stress field at infinity is derived. The solution of the boundary-integral equation is succeeded taking into consideration an appropriate Gauss quadrature rule for finite part integrals which is suitable for the numerical treatment of any plane crack with a smooth-contour shape and permit the fast convergence for the results. The problem of a circular and of an elliptical crack in an infinite body subjected to a uniform stress field at infinity is confronted; and the stress intensity factors are calculated. Copyright © 2001 John Wiley & Sons, Ltd. [source] Potential flow around obstacles using the scaled boundary finite-element methodINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 7 2003Andrew J. Deeks Abstract The scaled boundary finite-element method is a novel semi-analytical technique, combining the advantages of the finite element and the boundary element methods with unique properties of its own. The method works by weakening the governing differential equations in one co-ordinate direction through the introduction of shape functions, then solving the weakened equations analytically in the other (radial) co-ordinate direction. These co-ordinate directions are defined by the geometry of the domain and a scaling centre. The method can be employed for both bounded and unbounded domains. This paper applies the method to problems of potential flow around streamlined and bluff obstacles in an infinite domain. The method is derived using a weighted residual approach and extended to include the necessary velocity boundary conditions at infinity. The ability of the method to model unbounded problems is demonstrated, together with its ability to model singular points in the near field in the case of bluff obstacles. Flow fields around circular and square cylinders are computed, graphically illustrating the accuracy of the technique, and two further practical examples are also presented. Comparisons are made with boundary element and finite difference solutions. Copyright © 2003 John Wiley & Sons, Ltd. [source] Nursing Diagnosis and Nursing Theory: Exploration of Factors Inhibiting and Supporting Simultaneous UseINTERNATIONAL JOURNAL OF NURSING TERMINOLOGIES AND CLASSIFICATION, Issue 2 2002FAAN, Noreen C. Frisch PhD PURPOSE. To explore the values and philosophies of nursing theories that inhibit the simultaneous use of nursing diagnosis and nursing theory. SOURCES.Published articles, books, book chapters. DATA SYNTHESIS. Four factors in the literature and reflected in practice may have had a negative influence on the use of nursing diagnoses: (a) commitment to the uniqueness of each person, (b) an abandonment of the nursing process, (c) a perspective that nursing care is an evolving interaction, and (d) a belief that theory-derived language is more articulate and precise than standard classifications. PRACTICE IMPLICATIONS.Strategies for combining theory and diagnoses include emphasizing the diagnostic terms as professional shorthand and permitting flexibility in modifying diagnoses as needed; widely disseminating the concept that classification can be used effectively with newer iterations of the nursing process reflecting circular, simultaneous, and intuitive processes; developing classification language based on concepts of hypothesis and perception; and including diagnostic categories associated with theoretical perspectives. Search terms:Nursing classifications, nursing diagnoses, nursing theory Diagnostics infirmiers et théories de soins: Exploration des facteurs qui freinent et soutiennent leur utilisation simultanée BUT.Explorer les valeurs et les conceptions à la base des théories de soins qui inhibent I'utilisation des diagnostics infirmiers avec les théories de soin. SOURCES.Articles, manuels, chapitres d'ouvrages. SYNTHÈSE DES DONNÉES.Les données de la littérature professionnelle et l'examen de la pratique ont permis d'identifier quatre facteurs qui ont pu avoir une influence négative sur l'utilisation des diagnostics infirmiers: (a) l'importance donnée au caractère unique de chaque personne; (b) l'abandon de la démarche de soins; (c) l'idée que le soin est fait d'interactions en évolution constante; (d) la croyance que le langage découlant de la théorie est plus précis et articulé que les classifications normalisées. IMPLICATIONS POUR LA PRATIQUE.Quelques stratégies pourraient faciliter la combinaison de la théorie et des diagnostics, notamment: souligner le fait que les termes des diagnostics constituent une sorte de sténographie professionnelle et permettre la flexibilité pour les modifier; disséminer le fait que les classifications peuvent être utiles dans une démarche de soin rénovée, reflétant les aspects circulaires, simultanés et intuitifs du raisonnement; développer un langage basé sur les concepts d'hypothéses et de perceptions et inclure des catégories diagnostiques associées à des courants théoriques. Mots-clés:Classifications de soins, diagnostics infirmiers, théories de soins Diagnóstico de enfermagem e teoria de enfermagem: Exploração dos fatores inibidores e estimuladores do seu uso simultâneo OBJETIVO.Explorar os valores e filosofias das teorias de enfermagem que inibem o uso simultâneo dos diagnósticos de enfermagem e das teorias de enfermagem. FONTES.Artigos publicados, livros, capítulos de livros. SÍNTESE DOS DADOS.Quatro fatores citados na literatura e refletidos na prática podem ter tido uma influência negativa no uso dos diagnóstics de enfermagem: (a) compromisso com a singularidade de cada pessoa, (b) um abandono do processo de enfermagem, (c) uma perspectiva de que o cuidado de enfermagem é uma interação que evolui e (d) uma crença de que uma linguagem derivada da teoria é mais articulada e precisa do que classificações padronizadas. IMPLICAÇÕES PARA A PRÁTICA.Estratégias para combinar teoria e diagnósticos incluem enfatizar os termos diagnóstics como uma taquigrafia profissional e permitir flexibilidade para modificar diagnósticos sempre que necessário, disseminando amplamente o conceito de que a classificação pode ser usada efetivamente com novas repetições do processo de enfermagem, refletindo processos circulares, simultâneos e intuitivos; desenvolver uma linguagem de classificação baseada em conceitos de hipótese e percepção; e incluir categorias diagnósticas associadas com perspectivas teóricas. Palavras para busca:Classificações de enfermagem, diagnóstico de enfermagem, teoria de enfermagem Diagnóstico enfermero y teoría enfermera: Exploración de factores que inhiben y apoyan una utilización simultánea PROPÓSITO.Explorar los valores y filosofías de teorías enfermeras, que inhiben la utilización simultánea de diagnósticos y teorías enfermeras. FUENTES.Artículos publicados, libros, capítulos de libros. SÍNTESIS DE LOS DATOS.Cuatro factores reflejados en la práctica y en la bibliografía, pueden haber tenido una influencia negativa en la utilizatión de los diagnósticos de enfermería: (a) compromiso a la singularidad de cada persona, (b) abandono del proceso de enfermería, (c) una perspectiva de que los cuidados de enfermería son una interacción que evoluciona y (d) una creencia de que el lenguaje derivado de la teoría, es más preciso y expresa mejor que las clasificaciones estándar. IMPLICACIONES PARA LA PRÁCTICA.Las estrategias para combinar la teoría y los diagnósticos enfermeros, incluyen: Dar énfasis a los términos diagnósticos como una abreviatura profesional, permitir ser flexible al modificar diagnósticos si es necesario, diseminar ampliamente el concepto de que la clasificación puede usarse eficazmente con nuevas iteraciones del proceso enfermero que reflejen procesos circulares, simultáneos e intuitivos, desarrollar lenguajes de clasificación basados en los conceptos de hipótesis y percepción, Incluir categorías diagnósticas asociadas con perspectivas teóricas. Términos de búsqueda:Diagnósticos enfermeros, clasificaciones enfermeras y teoría enfermera [source] Trepanation in the Chachapoya region of northern PerúINTERNATIONAL JOURNAL OF OSTEOARCHAEOLOGY, Issue 1 2007K. C. Nystrom Abstract This paper discusses trepanation frequency data from the Chachapoya region of the northern highlands of Perú. New data from three skeletal samples are presented: Kuelap, Laguna Huayabamba, and Los Pinchudos, as well as isolated crania housed at the Chachapoya Museo Instituto Nacional de Cultura. The vast majority of the trepanations are circular in shape, except for one individual exhibiting as many as three roughly square trepanations. Evidence for healing is prevalent, with examples of both associated periosteal reaction of nearby outer table bone, as well as for healing of the insult itself. Only one case demonstrates a clear association between a traumatic injury and a trepanation event. The purpose or function of the remaining cases of trepanation, however, remains elusive. Copyright © 2006 John Wiley & Sons, Ltd. [source] Common generating function for two-dimensional hydrogen atom complete wave functionsINTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, Issue 1 2007L. Chaos-Cador Abstract The Schrödinger equation for the two-dimensional hydrogen atom is known to be separable and integrable in circular, parabolic, and elliptical coordinates. This makes it possible to construct a common generating function for the complete wave functions of the atom in the respective coordinates. The connections with the corresponding generating function and wave functions for the harmonic oscillator are recognized and applied in this work. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2007 [source] Mobile Livelihoods: The Sociocultural Practices of Circular Migrants between Puerto Rico and the United States,INTERNATIONAL MIGRATION REVIEW, Issue 2 2002Jorge Duany This article focuses on the bilateral flow of people between Puerto Rico and the United States - what has come to be known as circular, commuter, or revolving-door migration. It documents the migrants' livelihood practices based on a recent field study of population flows between Puerto Rico and the mainland. Specifically, the basic characteristics of multiple movers, one-time movers and nonmovers residing in Puerto Rico are compared. More broadly, the article assesses the implications of circular migration for Puerto Rican communities on and off the island. The author's basic argument is that the constant displacement of people - both to and from the island - blurs the territorial, linguistic, and juridical boundaries of the Puerto Rican nation. As people expand their means of subsistence across space, they develop multiple attachments to various localities. In the Puerto Rican situation, such mobile livelihoods are easier to establish than in other places because of the free movement of labor and capital between the island and the mainland. The author hypothesizes that circulation does not entail major losses in human capital for most Puerto Ricans, but rather often constitutes an occupational, educational, and linguistic asset. [source] Behavior, metamorphosis, and muscular organization of the predatory rotifer Acyclus inquietus (Rotifera, Monogononta)INVERTEBRATE BIOLOGY, Issue 3 2010Rick Hochberg Abstract. The atrochid rotifer, Acyclus inquietus, is a sedentary predator that lives within the colonies of its prey, the rotifer Sinantherina socialis. After larvae infiltrate and become associated with the colony, they secrete a permanent gelatinous tube and undergo metamorphosis to the adult stage. We followed settlement and metamorphosis using bright-field microscopy to document specific larval behaviors after eclosion, and used epifluorescence and confocal microscopy of phalloidin-labeled specimens to visualize some of the morphological changes that occur during metamorphosis. Upon eclosion, larvae possess paired eyespots and a ciliated corona that functions strictly in locomotion. After leaving the parent's gelatinous tube, larvae eventually settle on unoccupied colonies of S. socialis or on other substrates if colonies are unavailable. Settlement involves a period of gliding among colony members before attachment with the foot and the secretion of a gelatinous tube. After settlement, there is a drastic reconfiguration of the corona that involves loss of the eyespots, loss of the coronal cilia, and the formation of the cup-shaped infundibulum, a deep depression in the anterior of the head that leads to the mouth. The development of the infundibulum involves the expansion of tissues around the mouth and is accompanied by a reorientation of the underlying musculature that supplies the infundibulum and allows its use in prey capture. The arrangement of the muscles in the trunk and foot regions, which contain outer circular (complete and incomplete) and inner longitudinal bands, remains unchanged between ontogenetic stages, and reflects the condition characteristic of other rotifers. [source] A comparative study of the egg morphology in four species of Eubothrium (Cestoda: Pseudophyllidea) with comments on their early developmentINVERTEBRATE BIOLOGY, Issue 1 2006Roman Kuchta Abstract. Freshly released eggs from four species of the cestode Eubothrium (Eubothrium crassum, Eubothrium fragile, Eubothrium rugosum, and Eubothrium salvelini) were subjected to morphological and morphometric analysis. The eggs of the two freshwater species, E. rugosum and E. salvelini, were ovoid with a lobed embryophore whereas the eggs of the two marine species, E. crassum and E. fragile, were more circular with a smooth embryophore. However, the morphological differences between species were not readily evident to permit their clear distinction from one another. To discriminate species, a forward stepwise linear discriminant analysis, using six of the seven measured metric characters made on the eggs, was used, which gave 100% correct classification of two species, E. rugosum and E. salvelini, and a high proportion of correct classification for E. crassum (98%) and E. fragile (83%). Of the latter two species, one specimen of E. crassum and five specimens of E. fragile were misclassified between the respective groups. The principal characters used in the classification of the species were the width of the egg, the length of the mediolateral hooks, and the width of the oncosphere. To provide more information on the life cycle of each species, the eggs were used in a series of infection trials to identify appropriate intermediate hosts. Experimental infections with freshwater copepods were successful when exposed to the eggs of E. salvelini, partially successful when exposed to the eggs of marine E. crassum with 10% of the copepods becoming infected, but no infections were obtained when the eggs of E. fragile were used. [source] Scattering from laterally heterogeneous vesicles.JOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 3 2007Despite growing interest in the formation of domains or `rafts' in cell and model membranes, there have been relatively few attempts to characterize such systems via scattering techniques. Previously [Pencer et al. (2006). J. Appl. Cryst.39, 293,303], it was demonstrated that the Porod invariant, Q, could be used to detect lateral segregation. Here, the general theory for scattering from laterally heterogeneous vesicles is outlined and form factors are derived for vesicles containing either single circular or annular domains. These form factors are then applied to the analysis of neutron scattering data from heterogeneous vesicles. Potential advantages and limitations of this technique are also discussed. [source] | ||||||||||||||||||||||||||||||||||||||||||||||