177,706 research outputs found
An alternative semiparametric model for spatial panel data
No full textWe propose a semiparametric P-Spline model to deal with spatial panel data. This
model includes a non-parametric spatio-temporal trend, a spatial lag of the dependent
variable, and a time series autoregressive noise. Specifically, we consider a spatiotemporal
ANOVA model, disaggregating the trend into spatial and temporal main
effects, as well as second- and third-order interactions between them. Algorithms
based on spatial anisotropic penalties are used to estimate all the parameters in a closed
form without the need for multidimensional optimization. Monte Carlo simulations
and an empirical analysis of regional unemployment in Italy show that our model
represents a valid alternative to parametric methods aimed at disentangling strong and
weak cross-sectional dependence when both spatial and temporal heterogeneity are
smoothly distributed
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
"Closing the R&D Gap, Evaluating the Sources of R&D Spending"
No full textBoth spending and tax policies have been implemented in the United States with the goal of stimulating private sector research and development (R&D). Karier questions whether current R&D policy, especially the research and experimentation tax credit, can contribute to closing the gap between nondefense expenditures on R&D in the United States and such expenditures in other countries, such as Japan and Germany. He also explores possible changes to our current R&D policy to make it more effective.
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Letter from R. R. Zellick, Assistant Trust Officer, Anglo California National Bank of San Francisco, to Joseph R. Goodman, October 2, 1942
No full textLetter from R. R. Zellick, Assistant Trust Officer at The Anglo California National Bank of San Francisco, to Joseph R. Goodman, regarding property owned by Dave Tatsuno. Zellick mentions a dispute between current tenants and Tatsuno, and that Tatsuno has asked Goodman to help locate trustworthy tenants.Personal correspondence, organizational records, government documents, publications, and other papers created or collected by Joseph R. Goodman documenting the forced removal and incarceration of Japanese Americans during World War II, as well as organized resistance to incarceration. Included in the collection are records of the Japanese Young Men's Christian Association and the Japanese American Citizens' League in San Francisco, including papers of the Japanese YMCA's executive secretary Lincoln Kanai; Sakai family papers; Goodman's correspondence to and from Japanese American incarcerees, organizations opposing forced removal and incarceration of Japanese Americans, the War Relocation Authority, and others; publications, photographs, and ephemera from the Topaz Relocation Center, where Goodman taught high school; War Relocation Authority records and publications; and newspaper clippings, pamphlets, and reports about forced removal and incarceration created by various government, religious, and civic organizations, in California and nationwide
The impact of immigration on the internal mobility of natives and foreign-born residents: evidence from Italy
No full textThe relationship between immigration flows and internal mobility in Italy is investigated for the period 2003–11. Using semiparametric negative binomial gravity models with smooth spatio-temporal trends, and dealing with endogeneity issues through an instrumental variables approach, evidence is provided of a significant negative (or displacement) effect of new foreign immigrants on the internal mobility of foreign citizens and of Italian citizens with a low educational level, as well as a significant positive (or complementarity) effect of new foreign immigrants on the internal mobility of Italian citizens with a high educational level
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Apolipoprotein E and Alzheimer's diseases : signals and effects
No full textAlzheimer's Disease (AD) is the most frequent cause of dementia in the elderly. A diagnosis of AD is confirmed post-mortem by the accumulation of neuritic plaques (NP) and neurofibrillary tangles (NFTs) in brain tissue. NPs are extracellular deposits composed mainly of amyloid beta-peptide (A-beta) that is derived from the P amyloid precursor protein (APP). NFTs are found inside neurons and are characterised by structures referred to as paired helical filaments, whose major component is an abnormally phosphorylated and glycosylated form of the 'tau' protein.The most important risk factor for AD is polymorphism in the apolipoprotein E (apoE) gene. The apoE gene polymorphism gives rise to three different protein isoforms that differ in one single amino acid substitution and which show different lipid binding properties and three dimensional structure. The dose of the apoE4 isoform both increases the risk and reduces the age of onset for AD. The molecular mechanisms underlying this association are not fully understood, and in many cases are controversial. The present thesis, focuses on investigating several aspects of apoE biology in the context of AD.Paper I characterised factors that regulate apoE secretion in brain. ApoE secretion was shown to be modulated by adenosine 3':5'-cyclic monophosphate (cAMP) and factors that regulate intracellular cAMP. Retinoic acid potentiated, while the protein kinase C (PKC) activator phorbol 12- myristate 13-acetate (PMA) reversed the cAMP mediated effect. High PMA concentrations decreased apoE secretion. Also several agonists linked to the phospholipase C/PKC signalling pathway had opposite effects on apoE secretion, suggesting that the regulation of apoE by PKC may result from both positive and negative mechanisms. PKC activation and cAMP had opposite effects on nerve growth factor secretion than those seen for apoE secretion.Paper II aimed to clarify the interactions between A-beta, apoE isoforms and apoE containing lipoproteins with respect to neurotoxicity. In human SH-SY5Y neuroblastoma cells, both apoE3 and E4 were toxic when used alone but not when associated with P-very low density lipoproteins (beta-VLDL). Beta-VLDL also reduced the toxicity of A beta. These results suggest that the conformation of lipoprotein containing apoE particles may be important for determining the direct apoE contribution to neurotoxicity. No toxic effects were found in human fibroblasts, suggesting cell specificity.Papers III, IV and V explored the hypothesis that apoE may act as modulator of intracellular signalling pathways implicated in AD pathology. Paper III showed that apoE activates PKC without either isoform specific effects or further consequences for alpha-secretase APP cleavage. Paper IV showed that apoE4 and A-beta(1-42), but not apoE3, disrupt carbachol-induced phosphoinositide (P1) hydrolysis by an oxidative stress mediated mechanism. Moreover, apoE3 protected against the A-beta effect. Both apoE4 and A-beta(1-42) mediated disruptions of PI hydrolysis were protected by estrogen via an antioxidant effect and activation of phosphatidylinositol 3-kinase (PI3K). These findings may help to explain the lower effectiveness of treatments for AD based on cholinergic enhancers in apoE4 carriers, as well as shedding light on the protective mechanism of action of estrogen in AD.Paper V showed apoE isoform differences on the regulation of glycogen synthase kinase-3 beta (GSK-3 beta) activity. ApoE3 induced a mild transient early activation of GSK-3 beta that was possibly balanced by PKC activation. In contrast, apoE4 regulated GSK-30 activity in a biphasic manner, with a strong early activation and a subsequent inactivation of GSK-3 beta. ApoE4 also activated PKC-alpha and PKB, which may have given the subsequent GSK-3 beta inhibition. A beta(1-42) modulation of GSK-3 beta activity was also biphasic with a strong early activation and a subsequent inactivation. A beta(1-42) also induced an early and potent activation of PKC-alpha and a decreased PKB activity.These studies provide insight into some of the factors that control apoE secretion in brain and the neurotoxic effects of variant apoE isoforms. They also provide evidence that apoE has isoform specific effects on several signalling cascades involved in A beta production, tau phosphorylation, and apoptosis.List of scientific papersI. Cedazo-Minguez A, Hamker U, Meske V, Veh RW, Hellweg R, Jacobi C, Albert F, Cowburn RF, Ohm TG (2001). Regulation of apolipoprotein E secretion in rat primary hippocampal astrocyte cultures. Neuroscience. 105(3): 651-61. https://pubmed.ncbi.nlm.nih.gov/11516830II. Cedazo-Minguez A, Huttinger M, Cowburn RF (2001). Beta-VLDL protects against A beta(1-42) and apoE toxicity in human SH-SY5Y neuroblastoma cells. Neuroreport. 12(2): 201-6. https://pubmed.ncbi.nlm.nih.gov/11209921III. Cedazo-Minguez A, Wiehager B, Winblad B, Huttinger M, Cowburn RF (2001). Effects of apolipoprotein E (apoE) isoforms, beta-amyloid (Abeta) and apoE/Abeta complexes on protein kinase C-alpha (PKC-alpha) translocation and amyloid precursor protein (APP) processing in human SH-SY5Y neuroblastoma cells and fibroblasts. Neurochem Int. 38(7): 615-25. https://pubmed.ncbi.nlm.nih.gov/11290387IV. Cedazo-Minguez A, Cowburn RF (2001). Apolipoprotein E isoform-specific disruption of phosphoinositide hydrolysis: protection by estrogen and glutathione. FEBS Lett. 504(1-2): 45-9. https://pubmed.ncbi.nlm.nih.gov/11522294V. Cedazo-Minguez A, Wiehager B, Pei JJ, Cowburn RF (2002). Apolipoprotein E and beta-amyloid regulation of glycogen synthase kinase-3 beta. [Submitted]</p
Liftings for noncomplete probability spaces
No full textThe current state of knowledge concerning liftings for noncomplete probability spaces is discussed. This is a somewhat expanded version of the author's talk given at the 1991 Summer Conference on General Topology and Applications in Honor of Mary Ellen Rudin and Her Work.PT: S; CR: BURKE MR, IN PRESS P AM MATH S BURKE MR, 1991, ISRAEL J MATH, V73, P33 BURKE MR, 1992, ISRAEL J MATH, V79, P289 CARLSON T, THEOREM LIFTING CHRISTENSEN JPR, 1974, TOPOLOGY BOREL STRUC FREMLIN DH, 1989, HDB BOOLEAN ALGEBRAS, P877 INOESCUTULCEA A, 1966, 5TH P BERK S MATH ST, V2 IONESCUTULCEA A, 1967, CONTRIBUTIONS PROB 1, P63 IONESCUTULCEA A, 1969, TOPICS THEORY LIFTIN JECH TJ, 1978, SET THEORY JOHNSON RA, 1980, P AM MATH SOC, V80, P234 JUST W, IN PRESS T AM MATH S KUPKA J, 1983, INDIANA U MATH J, V32, P717 LOSERT V, 1983, LNM, V1080, P95 MAHARAM D, 1958, P AM MATH SOC, V9, P987 SHELAH S, 1983, ISRAEL J MATH, V45, P90 TALAGRAND M, 1982, P AM MATH SOC, V84, P379 VONNEUMANN J, 1931, CRELLES J MATH, V165, P109; NR: 18; TC: 0; J9: ANN N Y ACAD SCI; PG: 4; GA: BZ86BSource type: Electronic(1
GEOMETRÍA DESCRIPTIVA. SISTEMA ACOTADO: APLICACIONES
No full textCon esta publicación se pretende que los futuros graduados en Ingeniería que han de tener un conocimiento profundo de la representación del terreno y sus aplicaciones conozcan la herramienta imprescindible para ese fin: el sistema acotado (o de planos acotados). Para ello, en los temas primero (Generalidades) y decimocuarto (Anejos) del libro,se estudian los principios de geometría que son la base para construir dicho sistema; del tema segundo al sexto se muestra la teoría, propiamente dicha, del sistema acotado utilizando el abatimiento del plano proyectante, en primer lugar, y el abatimiento de un plano cualquiera, al final, como herramienta fundamental de estudio; del tema sexto hasta el noveno se aplica el sistema acotado a la resolución de problemas de intersección de rectas y planos con poliedros, con cilindros, con conos y con esferas por su importancia pedagógica; y del tema décimo al decimotercero, se estudian las aplicaciones más importantes del sistema acotado en ingeniería como son la resolución de cubiertas de edificaciones, la elaboración de planos y mapas topográficos, la realización de perfiles longitudinales y transversales, el estudio gráfico de las explanaciones necesarias en una obra, etc.Para facilitar, en lo posible, el aprendizaje del sistema acotado el libro contiene un número importa.Díaz Minguez, R. (2015). GEOMETRÍA DESCRIPTIVA. SISTEMA ACOTADO: APLICACIONES. Editorial Universitat Politècnica de València. https://riunet.upv.es/handle/10251/70607EDITORIA
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