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Interesting Insights (interesting + insight)
Selected AbstractsConstrained price, address, or logit brand demand models: An econometric comparison in the Boston fluid milk marketAGRIBUSINESS : AN INTERNATIONAL JOURNAL, Issue 2 2005Li Tian This article estimates a general linear demand model for three fluid milk brands. It finds perverse signs and complementarity among these substitutes. We develop three constrained models to eliminate perverse signs: a price conduct constraint in the linear model that links private label and Garelick pricing, a generalized Mills address model, and the logit model. Statistical tests indicate that each of the three constrained models produces acceptable substitution patterns and that none is preferred to the other two. On nonstatistical grounds, however, the Mills and price-constrained models perform best. This is the first empirical study of the Mills address model of private-label pricing. Finally, we demonstrate that estimated price-reaction functions and the corresponding total elasticities, which capture only strategic non-collusive interaction in these Nash Bertrand models, provide interesting insight into competition among brands. EconLit citation: L670, L130.] © 2005 Wiley Periodicals, Inc. Agribusiness 21: 149,166, 2005. [source] Using software trails to reconstruct the evolution of softwareJOURNAL OF SOFTWARE MAINTENANCE AND EVOLUTION: RESEARCH AND PRACTICE, Issue 6 2004Daniel M. German Abstract This paper describes a method to recover the evolution of a software system using its software trails: information left behind by the contributors to the development process of the product, such as mailing lists, Web sites, version control logs, software releases, documentation, and the source code. This paper demonstrates the use of this method by recovering the evolution of Ximian Evolution, a mail client for Unix. By extracting useful facts stored in these software trails and correlating them, it was possible to provide a detailed view of the history of this project. This view provides interesting insight into how an open source software project evolves and some of the practices used by its software developers. Copyright © 2004 John Wiley & Sons, Ltd. [source] On the use of the intensity-scale verification technique to assess operational precipitation forecastsMETEOROLOGICAL APPLICATIONS, Issue 1 2008Gabriella Csima Abstract The article describes the attempt to include the intensity-scale technique introduced by Casati et al. (2004) into a set of standardized verifications used in operational centres. The intensity-scale verification approach accounts for the spatial structure of the forecast field and allows the skill to be diagnosed as a function of the scale of the forecast error and intensity of the precipitation events. The intensity-scale method has been used to verify two different resolutions of the European Centre for Medium-Range Weather Forecasts (ECMWF) operational quantitative precipitation forecast (QPF) over France, and to compare the performance of the ECMWF and the Hungarian Meteorological Service operational model (ALADIN) forecasts, run over Hungary. Two case studies have been introduced, which show some interesting insight into the spatial scale of the error. The distribution of daily skill score for an extended period of time is also presented. The intensity-scale technique shows that the forecasts in general exhibit better skill for large-scale events, and lower skill for small-scale and intense events. In the paper, it is mentioned how some of the stringent assumptions on the domain over which the method can be applied, and the availability of the matched forecasts and observations, can limit its usability in an operational environment. Copyright © 2008 Royal Meteorological Society [source] Robust estimation of the SUR modelTHE CANADIAN JOURNAL OF STATISTICS, Issue 2 2000Martin Bilodeau Abstract This paper proposes robust regression to solve the problem of outliers in seemingly unrelated regression (SUR) models. The authors present an adaptation of S -estimators to SUR models. S -estimators are robust, have a high breakdown point and are much more efficient than other robust regression estimators commonly used in practice. Furthermore, modifications to Ruppert's algorithm allow a fast evaluation of them in this context. The classical example of U.S. corporations is revisited, and it appears that the procedure gives an interesting insight into the problem. Les auteurs proposent une méthode de régression robuste pour résoudre le problème des valeurs aberrantes dans les modèles SUR. Ils adaptent les S -estimateurs dans les modèles SUR. Les S -estimateurs sont robustes, ont un haut point de rupture et sont beaucoup plus efficaces que les autres estimateurs robustes de régression couramment utilisés en pratique. De plus, une modification de l'algorithme de Ruppert permet une évaluation rapide de ces estimateurs dans ce contexte. La procédure donne une compréhension intéressante d'un problème classique portant sur des compagnies américaines. [source] Transition-State Energy and Position along the Reaction Coordinate in an Extended Activation Strain Model,CHEMPHYSCHEM, Issue 8 2007G. Theodoor de Jong Dr. Abstract We investigate palladium-induced activation of the CH, CC, CF, and CCl bonds in methane, ethane, cyclopropane, fluoromethane, and chloromethane, using relativistic density functional theory (DFT) at ZORA-BLYP/TZ2P. Our purpose is to arrive at a qualitative understanding, based on accurate calculations, of the trends in activation barriers and transition state (TS) geometries (e.g. early or late along the reaction coordinate) in terms of the reactants' properties. To this end, we extend the activation strain model (in which the activation energy ,E, is decomposed into the activation strain ,E,strain of the reactants and the stabilizing TS interaction ,E,int between the reactants) from a single-point analysis of the TS to an analysis along the reaction coordinate ,, that is, ,E(,)=,Estrain(,)+,Eint(,). This extension enables us to understand qualitatively, trends in the position of the TS along , and, therefore, the values of the activation strain ,E,strain=,Estrain(,TS) and TS interaction ,E,int=,Eint(,TS) and trends therein. An interesting insight that emerges is that the much higher barrier of metal-mediated CC versus CH activation originates from steric shielding of the CC bond in ethane by CH bonds. Thus, before a favorable stabilizing interaction with the CC bond can occur, the CH bonds must be bent away, which causes the metal,substrate interaction ,Eint(,) in CC activation to lag behind. Such steric shielding is not present in the metal-mediated activation of the CH bond, which is always accessible from the hydrogen side. Other phenomena that are addressed are anion assistance, competition between direct oxidative insertion (OxIn) versus the alternative SN2 pathway, and the effect of ring strain. [source] The Rift: Explaining Europe's Divergent Iraq Policies in the Run-Up of the American-Led War on IraqFOREIGN POLICY ANALYSIS, Issue 3 2006JÜRGEN SCHUSTER America's plan to attack Iraq split Europe down the middle. Why did European countries take such different stances toward the Bush administration's policy? This article examines three different approaches, each rooted in one of international relations (IRs) prominent schools of thought, with regard to their explanatory power in this specific puzzle. Firstly, it shows that public opinion (utilitarian,liberal approach) cannot account for whether a state joined the "coalition of the willing" or not. Secondly, it demonstrates that in Eastern Europe systemic forces of power relations (neorealist approach) are suitable for explaining state behavior, but not in Western Europe. Thirdly, it shows that the ideological orientations of governments (liberal,constructivist approach) were the decisive factor in determining whether a state supported the United States in Western Europe, but not in Eastern Europe. These results offer some interesting insights for the theoretical debate in IRs theory and foreign policy analysis, which are discussed in the final section of the article. In regard to foreign policy analysis, for example, the results of this study propose to "bring political parties in." [source] Understanding the role of managerial agency in achieving business benefits from ERP systemsINFORMATION SYSTEMS JOURNAL, Issue 3 2010Lorraine Staehr Abstract Previous enterprise resource planning (ERP) research has identified ,top management support' as an important factor in implementation success. However, most studies are short on the detail of exactly how and why ,top management support' contributes to ERP success. Moreover, although ,improved management decision-making' is often claimed as a business benefit of ERP systems, there is little evidence in previous ERP research of it having actually occurred. This paper examines the role of managerial agency at all levels in four Australian manufacturing organizations in achieving business benefits from ERP systems during the post-implementation period. The research contributes to current understanding of the role of managerial agency in achieving business benefits from ERP systems by providing theoretically based, detailed and interesting insights from four interpretive case studies. [source] In-line analysis of a fluid bed pellet coating process using a combination of near infrared and Raman spectroscopyJOURNAL OF CHEMOMETRICS, Issue 7-8 2010Andrey Bogomolov Abstract Near infrared (NIR) and Raman spectroscopic analyzers applied through an immersion Lighthouse Probe (LHP) were used for simultaneous in-line monitoring of a fluid bed pellet coating process. Multivariate curve resolution analysis of data, collected from four pilot-scale batches, has shown that the two techniques deliver complementary information about the process and their combination may be synergistic. This data analysis enabled a much better understanding of some of the process observations and also gave some interesting insights into the best way to use the techniques themselves. PLS regression analysis of the product moisture and the quantity of coating material sprayed was performed using NIR and Raman data blocks both separately and in combination. The performance of method combination compared to individual techniques is analyzed and discussed. Copyright © 2010 John Wiley & Sons, Ltd. [source] Signalling molecules and growth factors for tissue engineering of cartilage,what can we learn from the growth plate?,JOURNAL OF TISSUE ENGINEERING AND REGENERATIVE MEDICINE, Issue 6 2009Christoph Brochhausen Abstract Modern tissue engineering concepts integrate cells, scaffolds, signalling molecules and growth factors. For the purposes of regenerative medicine, fetal development is of great interest because it is widely accepted that regeneration recapitulates in part developmental processes. In tissue engineering of cartilage the growth plate of the long bone represents an interesting, well-organized developmental structure with a spatial distribution of chondrocytes in different proliferation and differentiation stages, embedded in a scaffold of extracellular matrix components. The proliferation and differentiation of these chondrocytes is regulated by various hormonal and paracrine factors. Thus, members of the TGF, superfamily, the parathyroid hormone-related peptide,Indian hedgehog loop and a number of transcription factors, such as Sox and Runx, are involved in the regulation of chondrocyte proliferation and differentiation. Furthermore, adhesion molecules, homeobox genes, metalloproteinases and prostaglandins play a role in the complex regulation mechanisms. The present paper summarizes the morphological organization of the growth plate and provides a short but not exhaustive overview of the regulation of growth plate development, giving interesting insights for tissue engineering of cartilage. Copyright © 2009 John Wiley & Sons, Ltd. [source] The structure and evolution of the murine inhibitor of carbonic anhydrase: A member of the transferrin superfamilyPROTEIN SCIENCE, Issue 9 2010Brian E. Eckenroth Abstract The original signature of the transferrin (TF) family of proteins was the ability to bind ferric iron with high affinity in the cleft of each of two homologous lobes. However, in recent years, new family members that do not bind iron have been discovered. One new member is the inhibitor of carbonic anhydrase (ICA), which as its name indicates, binds to and strongly inhibits certain isoforms of carbonic anhydrase. Recently, mouse ICA has been expressed as a recombinant protein in a mammalian cell system. Here, we describe the 2.4 Å structure of mouse ICA from a pseudomerohedral twinned crystal. As predicted, the structure is bilobal, comprised of two ,-, domains per lobe typical of the other family members. As with all but insect TFs, the structure includes the unusual reverse ,-turn in each lobe. The structure is consistent with the fact that introduction of two mutations in the N-lobe of murine ICA (mICA) (W124R and S188Y) allowed it to bind iron with high affinity. Unexpectedly, both lobes of the mICA were found in the closed conformation usually associated with presence of iron in the cleft, and making the structure most similar to diferric pig TF. Two new ICA family members (guinea pig and horse) were identified from genomic sequences and used in evolutionary comparisons. Additionally, a comparison of selection pressure (dN/dS) on functional residues reveals some interesting insights into the evolution of the TF family including that the N-lobe of lactoferrin may be in the process of eliminating its iron binding function. [source] A tale of two books: Bessarion's In Calumniatorem Platonis and George of Trebizond's Comparatio Philosophorum Platonis et Aristotelis1RENAISSANCE STUDIES, Issue 1 2008John Monfasani The two central Latin works of the Plato-Aristotle Controversy of the Fifteenth Century were George of Trebizond's Comparatio Philosophorum Platonis et Aristotelis and Cardinal Bessarion's In Calumniatorem Platonis in response to George. The Renaissance fortuna of Bessarion's work is well known and reflects the relative success it enjoyed. George's Comparatio, however, had a much harder time of it. The story of its eventually printing in 1523 involves us tracing the history of MS Vat. Lat. 3382 of the Biblioteca Apostolica Vaticana through Central Europe until its arrival in Venice. The key figure in the printing proved to be the imperial official Jacopo Bannisio. A marginal note by the Englishman Robert Ridley in a copy of Bessarion's work now at Yale University reporting a conversation he had with Jacques Lefèvre d'Etaples in Paris provides interesting insights on how Lefèvre and others viewed the conflict between Bessarion and George as well as on the fortuna of George's Comparatio. [source] Function of plastidial pyruvate kinases in seeds of Arabidopsis thaliana,THE PLANT JOURNAL, Issue 3 2007Sébastien Baud Summary Pyruvate kinase (PK) catalyses the irreversible synthesis of pyruvate and ATP, which are both used in multiple biochemical pathways. These compounds are essential for sustained fatty acid production in the plastids of maturing Arabidopsis embryos. Using a real-time quantitative reverse transcriptase (RT)-PCR approach, the three genes encoding putative plastidial PKs (PKps) in Arabidopsis, namely PKp1 (At3g22960), PKp2 (At5g52920) and PKp3 (At1g32440), were shown to be ubiquitously expressed. However, only PKp1 and PKp2 exhibited significant expression in maturing seeds. The activity of PKp1 and PKp2 promoters was consistent with this pattern, and the study of the PKp1:GFP and PKp2:GFP fusion proteins confirmed the plastidial localization of these enzymes. To further investigate the function of these two PKp isoforms in seeds comprehensive functional analyses were carried out, including the cytological, biochemical and molecular characterization of two pkp1 and two pkp2 alleles, together with a pkp1pkp2 double mutant. The results obtained outlined the importance of these PKps for fatty acid synthesis and embryo development. Mutant seeds were depleted of oil, their fatty acid content was drastically modified, embryo elongation was retarded and, finally, seed germination was also affected. Together, these results provide interesting insights concerning the carbon fluxes leading to oil synthesis in maturing Arabidopsis seeds. The regulation of this metabolic network by the WRINKLED1 transcription factor is discussed, and emphasizes the role of plastidial metabolism and the importance of its tight regulation. [source] Curcumin in Cancer Chemoprevention: Molecular Targets, Pharmacokinetics, Bioavailability, and Clinical TrialsARCHIV DER PHARMAZIE, Issue 9 2010Adeeb Shehzad Abstract Curcumin (diferuloylmethane), a derivative of turmeric is one of the most commonly used and highly researched phytochemicals. Abundant sources provide interesting insights into the multiple mechanisms by which curcumin may mediate chemotherapy and chemopreventive effects on cancer. The pleiotropic role of this dietary compound includes the inhibition of several cell signaling pathways at multiple levels, such as transcription factors (NF-,B and AP-1), enzymes (COX-2, MMPs), cell cycle arrest (cyclin D1), proliferation (EGFR and Akt), survival pathways (,-catenin and adhesion molecules), and TNF. Curcumin up-regulates caspase family proteins and down-regulates anti-apoptotic genes (Bcl-2 and Bcl-XL). In addition, cDNA microarrays analysis adds a new dimension for molecular responses of cancer cells to curcumin at the genomic level. Although, curcumin's poor absorption and low systemic bioavailability limits the access of adequate concentrations for pharmacological effects in certain tissues, active levels in the gastrointestinal tract have been found in animal and human pharmacokinetic studies. Currently, sufficient data has been shown to advocate phase II and phase III clinical trials of curcumin for a variety of cancer conditions including multiple myeloma, pancreatic, and colon cancer. [source] MAD phasing using the (Ta6Br12)2+ cluster: a retrospective studyACTA CRYSTALLOGRAPHICA SECTION D, Issue 5 2008Oliwia Pasternak The crystal structure of cytokinin-specific binding protein (CSBP) containing four independent molecules with 4 × 155 = 620 residues in the asymmetric unit of the P64 unit cell has been solved by three-wavelength MAD using 1.8,Å resolution data recorded from a crystal derivatized with the dodecabromohexatantalum cation (Ta6Br12)2+. The diffraction data contained a very strong anomalous signal (allowing successful phasing even using peak SAD data alone) despite the fact that the five (Ta6Br12)2+ clusters found in the asymmetric unit have low occupancy (about 0.3). The derivative structure has been successfully refined to R = 0.158, providing interesting details on the geometry of the (Ta6Br12)2+ cluster, its interactions with the protein and on the backsoaking of a cytokinin ligand that was originally part of a CSBP,cytokinin complex in the native crystals used for (Ta6Br12)2+ derivatization. A simulation analysis of the phasing power of the (Ta6Br12)2+ ions at artificially imposed resolution limits shows that it is not possible to resolve the individual Ta atoms if the dmin limit of the data is higher than 2.9,Å. Additionally, for successful Ta identification the (Ta6Br12)2+ complex should be specifically bound and ordered. Good binding at the protein surface is facilitated by the presence of acidic groups, indicating higher pH buffer conditions to be preferable. In addition, the water channels in the crystal should be sufficiently wide (at least 11,Å) to allow free diffusion of the (Ta6Br12)2+ ions on soaking. A retrospective look at the initial molecular-replacement calculations provides interesting insights into how the peculiar packing mode and strong bias of the molecular-replacement-phased electron-density maps had hindered successful solution of the structure by this method. [source] | ||||||||||||||||