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Simple Solution (simple + solution)
Selected AbstractsGrid-induced biases in connectivity metric implementations that use regular gridsECOGRAPHY, Issue 3 2010Adam G. Dunn Graph-theoretic connectivity analyses provide opportunities to solve problems related to the management, design and maintenance of fragmented landscapes. However, several modern connectivity metrics are implemented using algorithms that are affected by a grid-induced bias. When paths through a regular grid are calculated, distance errors are introduced into the metric outputs, with patterns based on the shape and orientation of the underlying grid structure. The bias is significant in the proposed implementations of the conditional minimum transit cost method introduced by Pinto and Keitt, and the effective resistance method introduced by McRae, Dickson, Keitt and Shah. One solution for ameliorating the bias that affects regular grids is to use an irregular lattice to represent the landscape. The purpose of this paper is to serve as a timely reminder of the grid-induced bias and to provide a demonstration of the irregular grid as a simple solution to the problem. [source] THE CONFLICT BETWEEN INTERPERSONAL RELATIONS AND ABSTRACT SYSTEMS IN EDUCATIONEDUCATIONAL THEORY, Issue 2 2007Benjamin Endres Endres uses Anthony Giddens's account of "abstract systems" and "pure" relations to suggest that the tension that teachers face is not only the result of opposing ideologies or philosophies of teaching, but it is the product of conflicting undercurrents in modern social and economic life. Although there is no simple solution to the ambiguous and contested status of teaching, Endres points to two examples of how the interpersonal dimensions of teaching may gain recognition and support by the institutional system of schooling: research on the effects of class size and legal guarantees for individualized educational plans in the area of special education. He concludes by emphasizing the particular challenge of cultivating interpersonal relations for the most disadvantaged students. [source] Controllable Synthesis of Cu2O Microcrystals via a Complexant-Assisted Synthetic RouteEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 7 2010Wanqun Zhang Abstract A novel method using Cu(AC)2·H2O and dimethylglyoxime as reagents has been successfully developed for the controllable synthesis of Cu2O microcrystals with distinctive morphologies, including porous hollow microspheres, octahedral microcages, and microcrystals with truncated corners and edges and octahedral microcrystals. These structures can be fine-tuned by varying reaction temperature, reaction time, and concentration. The products were characterized by X-ray diffraction, field emission scanning electron microscopy, X-ray photoelectron spectra, and UV/Vis diffuse reflectance spectra. This is the first report of the preparation of the novel microcage structure of Cu2O through a simple solution-based route. By investigating the intermediate products which resemble the final crystal structures, a possible growth mechanism is proposed. Moreover, the investigations showed that the various 3D architectures of the as-made products exhibit different abilities to catalytically degrade rhodamine-B. Our work shows that octahedral Cu2O crystals with entirely {111} faces are photocatalytically more active than octahedral microcrystals with truncated corners and edges, suggesting the {111} faces of Cu2O nanostructures are catalytically more active than the {100} and {110} faces. Due to dual effect of the cavity structure and the {111} surfaces, the octahedral microcages with truncated corners and edges exhibit a higher extent of the photodecomposition reaction. As a result of very slow photocorrosion rate of the Cu2O microcrystal, it is expected that these microcrystals with different surfaces may find more applications in photocatalysis. [source] Explaining the Weak Relationship Between Job Performance and Ratings of Job PerformanceINDUSTRIAL AND ORGANIZATIONAL PSYCHOLOGY, Issue 2 2008KEVIN R. MURPHY Ratings of job performance are widely viewed as poor measures of job performance. Three models of the performance,performance rating relationship offer very different explanations and solutions for this seemingly weak relationship. One-factor models suggest that measurement error is the main difference between performance and performance ratings and they offer a simple solution,that is, the correction for attenuation. Multifactor models suggest that the effects of job performance on performance ratings are often masked by a range of systematic nonperformance factors that also influence these ratings. These models suggest isolating and dampening the effects of these nonperformance factors. Mediated models suggest that intentional distortions are a key reason that ratings often fail to reflect ratee performance. These models suggest that raters must be given both the tools and the incentive to perform well as measurement instruments and that systematic efforts to remove the negative consequences of giving honest performance ratings are needed if we hope to use performance ratings as serious measures of job performance. [source] A Dynamic Analysis of a Spatial Manipulator to Determine Payload WeightJOURNAL OF FIELD ROBOTICS (FORMERLY JOURNAL OF ROBOTIC SYSTEMS), Issue 7 2003Carl D. Crane III This paper presents a methodology whereby the payload weight of a serial manipulator can be determined from a minimum set of sensor data, i.e., joint angle and joint torque measurements. The particular manipulator geometry that is analyzed is a four degree-of-freedom serial chain that is commonly used in excavator systems. It was quite remarkable that a relatively simple solution was obtained for the payload weight considering that there are a total of nine unknown moments and cross moments of inertia of the payload together with the unknown location of the center of mass. Example calculations are presented. © 2003 Wiley Periodicals, Inc. [source] KINETICS OF SOYBEAN LIPOXYGENASES ARE RELATED TO pH, SUBSTRATE AVAILABILITY AND EXTRACTION PROCEDURESJOURNAL OF FOOD BIOCHEMISTRY, Issue 2 2008VERONICA S. CHEDEA ABSTRACT The kinetic patterns of pure soy lipoxygenase LOX-1 and crude or defatted soybean extracts containing LOX isoenzymes (LOX-1, LOX-2 and LOX-3) were studied by UV spectrometry at 234 and 280 nm, depending on their extraction and measurement conditions. Different pHs (from 6.0 to 9.0), corresponding to specific activation of LOX isoenzymes and the ratios of enzyme protein per substrate were used in order to evaluate the enzyme rates, as indicators of its affinity for substrate in different environments. The crude soy extract contained mainly LOX-1 activity (measured at 234 nm, at pH 9.0) and LOX-3, in an approximate ratio of 3:1. The LOX-2 activity was very low. The defatted extracts buffered at pH 6.8 and 7.1 showed a low LOX-1 and LOX 2 activity, but mostly LOX-3 activity (measured at 280 nm, at pH 7.1), with a mirror-type relation between the enzyme/substrate ratio and their enzymatic specific activity. The results suggest that defatting inhibits specifically the LOX-1 activity and indicate the possibility to modulate LOX activity by modifications of enzyme/substrate ratios and modifications of pH in the enzyme environment. PRACTICAL APPLICATIONS Because of the specific kinetic behaviors of the three different LOXs found in crude soy extracts involved in off-flavor generation, one can modulate the inhibition of these isoenzymes during soybean processing. Our experiments showed that pH variation could be a simple solution to inhibit the LOX isoenzymes, and therefore, the off-flavor generation. From the analytical point of view, the techniques described in this article are designed to be as simple as possible, and easy to use at large-scale level in food industry (food chain control). The idea is to minimize the number of separate chemical manipulations and, thereby, minimize errors. These studies can offer the background of further inhibition experiments in vitro using natural extracts. The LOX inhibition by natural antioxidants is related as well to pH and other factors influencing the enzyme's activity; this idea can be also valorized practically in the future. [source] Examination of the impact of a range of Pluronic surfactants on the in-vitro solubilisation behaviour and oral bioavailability of lipidic formulations of atovaquoneJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 6 2006Leab Sek Exogenous surfactants are increasingly used to enhance the dispersion properties of lipid-based formulations of poorly water-soluble drugs, yet their possible effects on formulation digestion and oral bioavailability in-vivo are not well documented. In this study, in-vitro dispersion and digestion experiments were conducted using formulations comprising a blend of long-chain glycerides, ethanol, a model poorly water-soluble drug (atovaquone), and a series of surfactants including Cremophor EL and a range of Pluronic surfactants (Pluronics L121, L61, L72, L43 and F68). Inclusion of Cremophor EL, a surfactant with a high hydrophilic-lipophilic balance (HLB), promoted complete digestion of the formulation and effective dispersion and solubilisation of the lipolytic products and co-administered drug. Surprisingly, formulations containing the Pluronic (L121) with the lowest HLB (0.5) equally effectively promoted digestion and drug solubilisation and a trend towards decreased digestion and drug solubilisation was observed with Pluronics of increasing HLB values. All formulations effectively prevented drug precipitation, suggesting possible utility in-vivo, and no correlation was evident between the ability of the formulations to self-emulsify on dispersion and to promote drug solubilisation on digestion. Subsequent assessment of the oral bioavailability of atovaquone after administration of formulations containing Cremophor EL or Pluronic L121 or a simple solution of atovaquone in long-chain glycerides confirmed the utility of lipid-based formulations for enhancing the oral bioavailability of poorly water-soluble drugs such as atovaquone, but also indicated that in some cases microemulsion preconcentrate formulations may not provide additional bioavail-ability benefits beyond that achievable using simple lipid solutions. [source] The use of physical restraint in critical careNURSING IN CRITICAL CARE, Issue 1 2007Karen Hine Abstract Critically ill patients are at high risk for the development of delirium and agitation, resulting in non-compliance with life-saving treatment. The use of physical restraint appears to be a useful and simple solution to prevent this treatment interference. In reality, restraint is a complex topic, encompassing physical, psychological, legal and ethical issues. This article briefly discusses the incidence of delirium and agitation in critically ill patients and examines in detail the method of physical restraint to manage treatment interference. The historical background of physical restraint is discussed and the prevalence of its use in critical care units across the world examined. Studies into the use of physical restraint are analysed, and in particular the physical effects on patients discussed. The use of physical restraint raises many legal, ethical and moral questions for all health care professionals; therefore, this study aims to address these questions. This article concludes by emphasizing areas of future practice development in intensive care units throughout the UK. [source] Perspektiven für mehr Jobs in DeutschlandPERSPEKTIVEN DER WIRTSCHAFTSPOLITIK, Issue 4 2001Klaus F. Zimmermann There is no simple solution to the German unemployment dilemma. Neither too high wages, nor unionized central bargaining, nor the evidence of the effects of the welfare state deliver a simple explanation. The East German experience confirms this view. A solution needs to combine flexibility with economic growth. More flexible product markets could help to generate the higher demand for unskilled labour that is so badly needed. [source] Freeze avoidance: a dehydrating moss gathers no icePLANT CELL & ENVIRONMENT, Issue 10 2010THOMAS LENNÉ ABSTRACT Using cryo-SEM with EDX fundamental structural and mechanical properties of the moss Ceratodon purpureus (Hedw.) Brid. were studied in relation to tolerance of freezing temperatures. In contrast to more complex plants, no ice accumulated within the moss during the freezing event. External ice induced desiccation with the response being a function of cell type; water-filled hydroid cells cavitated and were embolized at ,4 °C while parenchyma cells of the inner cortex exhibited cytorrhysis, decreasing to ,20% of their original volume at a nadir temperature of ,20 °C. Chlorophyll fluorescence showed that these winter acclimated mosses displayed no evidence of damage after thawing from ,20 °C while GCMS showed that sugar concentrations were not sufficient to confer this level of freezing tolerance. In addition, differential scanning calorimetry showed internal ice nucleation occurred in hydrated moss at ,,12 °C while desiccated moss showed no evidence of freezing with lowering of nadir temperature to ,20 °C. Therefore the rapid dehydration of the moss provides an elegantly simple solution to the problem of freezing; remove that which freezes. [source] A simple solution to the k -core problemRANDOM STRUCTURES AND ALGORITHMS, Issue 1-2 2007Svante Janson Abstract We study the k -core of a random (multi)graph on n vertices with a given degree sequence. We let n ,,. Then, under some regularity conditions on the degree sequences, we give conditions on the asymptotic shape of the degree sequence that imply that with high probability the k -core is empty and other conditions that imply that with high probability the k -core is non-empty and the sizes of its vertex and edge sets satisfy a law of large numbers; under suitable assumptions these are the only two possibilities. In particular, we recover the result by Pittel, Spencer, and Wormald (J Combinator Theory 67 (1996), 111,151) on the existence and size of a k -core in G(n,p) and G(n,m), see also Molloy (Random Struct Algor 27 (2005), 124,135) and Cooper (Random Struct Algor 25 (2004), 353,375). Our method is based on the properties of empirical distributions of independent random variables and leads to simple proofs. © 2006 Wiley Periodicals, Inc. Random Struct. Alg.,, 2007 [source] Tetraethylenepentamine-Directed Controllable Synthesis of Wurtzite ZnSe Nanostructures with Tunable MorphologyCHEMISTRY - A EUROPEAN JOURNAL, Issue 31 2008Baojuan Xi Dr. Abstract A novel tetraethylenepentamine (TEPA)-directed method has been successfully developed for the controlled synthesis of ZnSe particles with distinctive morphologies, including nanobelts, nanowires, and hierarchically solid/hollow spheres. These structures, self-assembled from nanobelts and nanorods, have been synthesized by adjusting the reaction parameters, such as the solvent composition, reaction temperature, and the aging time. Results reveal that the volume ratio of H2O and TEPA plays a crucial role in the final morphology of ZnSe products. The mechanisms of phase formation and morphology control of ZnSe particles are proposed and discussed in detail. The products have been characterized by means of X-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy (TEM), selected area electron diffraction, high-resolution TEM, Raman spectra and luminescence spectroscopy. The as-prepared ZnSe nanoparticles display shape- and size-dependent photoluminescent optical properties. This is the first time to report preparation of complex hollow structures of ZnSe crystals with hierarchy through a simple solution-based route. This synthetic route is designed to exploit a new H2O/TEPA/N2H4,H2O system possibly for the preparation of other semiconductor nanomaterials. [source] Donor,Acceptor Systems: Energy Transfer from CdS Quantum Dots/Rods to Nile Red DyeCHEMPHYSCHEM, Issue 14 2008Suparna Sadhu Abstract We demonstrate strong evidence of shape-dependent efficient resonance energy transfer between CdS quantum dots (QDs) and quantum rods (QRs) (donor) to Nile Red dye (acceptor). We also report a simple solution-based method for the preparation of high quality CdS QDs and CdS QRs at relatively low temperature. The observed quenching of PL intensities are 78.8,% and 63.8,% for CdS QDs and QRs, respectively in the presence of Nile Red dye. The calculated energy-transfer efficiencies are 45,% and 19,% from QDs and QRs to dyes, respectively. The energy transfer varies with changing the shape of the nanoparticles. The estimated Förster distances (R0) are 37.8 and 33.8 Å for CdS QDs and QRs, respectively. In the present study, the estimated distances (r) between one donor and one acceptor are 39.1 and 43.1 Å for QDs and QRs, respectively, using the efficiency of Förster resonance energy transfer (FRET) which depends on the inverse sixth power of the distance of separations between one nanocrystal and one dye molecule. Considering single donor and multiple acceptors interactions, the calculated average distances (rn) between the donor and acceptor are 47.7 and 53.9 Å for QD's and QR's, respectively. The steady-state and time-resolved spectroscopic analysis of nanoassemblies confirm the formation of one donor and multiple acceptors. [source] The effect of surface,solute interactions on the transport of solutes through porous materialsEUROPEAN JOURNAL OF SOIL SCIENCE, Issue 3 2009D. A. Rose Summary We have investigated the effect of differences in surface charge, valency of ion, solute concentration, solution flux and physical structure on the leaching and uptake of individual ions from simple solutions flowing through porous materials. We studied the miscible displacement of solutions of four salts (KBr, K2SO4, CaBr2 and CaSO4) having different cation : anion ratios separately through three inert materials (ballotini, pumice and ceramic) and two sizes of a reactive material (sepiolite) over several ranges of concentration (c) and at many pore-water velocities (v) under steady vertical saturated flow. Breakthrough curves of individual effluent ions (K+, Br,, Ca2+ and SO42,) were analysed by CXTFIT 2.0 to optimize transport parameters (retardation factor, R; dispersion coefficient, K) assuming that transport was governed by the convective,dispersion equation. In the inert materials, R did not differ significantly from 1 irrespective of c. In sepiolite, R was < 1 for anions and > 1 for cations, and became more extreme as c decreased. R varied with the valency of the anions, as predicted by diffuse double layer theory, and with that of the cations by a simple charge balance. Freundlich isotherms, reconstructed from R values, described the sorption of the cations and exclusion of the anions. For the inert materials, K did not depend on the ion or c and increased monotonically with v. For sepiolite, K also increased with v and with small but non-significant differences between ions and concentrations. The K(v) functions were consistent with Passioura's theory of dispersion in aggregated media, and the transport was reversible as R and K values did not depend on whether the media were being leached or resalinized. The effective dispersion coefficient of an ion is K* = K/R so, although K(v) appears to be unaffected by ion or concentration of solute in sepiolite, K*(v) will be affected. Thus, the controlling factor of these surface,solute interactions is R. [source] Making sex: law's narratives of sex, gender and identityLEGAL STUDIES, Issue 1 2003Laura Grenfell From the 1970 decision of Corbett, onwards, legal narratives established two modes of categorising complex social identi5 in relation to sex and gender. These narratives responded to complex identity questions by attempting to simplify identity by limiting it to biological factors or anatomical and psychological factors. I demonstrate that the law's struggle to ,make' sex is reflected to a certain extent by feminism's trajectory, in that feminisms have also attempted to grapple with these complex questions, and often opted for the same simple solutions to the problem of understanding gender, sex and identity. The aim of this paper is to show that some strands of feminist theory, specifically post-structuralist feminist theory, can produce a more progressive and constructive approach to determining sex in their ability to illuminate the complexities of identity. In particular, my aim is to urge those courts that ,make' sex to consider these complexities and the implications that flow from placing transgender people into rigid arid narrow categories. [source] Why is Knowledge Management So Difficult?BUSINESS STRATEGY REVIEW, Issue 1 2001Julian Birkinshaw Knowledge management promises much, but often delivers very little. There are no simple solutions to this challenge. This article starts by trying to define what knowledge management is. It then identifies where the problems lie and suggests five steps to resolve those problems. The article is based on research in a dozen leading companies, including HP, Ericsson, ABB, Skandia and Xerox. [source] | |||||||||||||||||||