Main Centre (main + centre)

Distribution by Scientific Domains


Selected Abstracts


In search of simple structures in climate: simplifying EOFs

INTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 1 2006
A. Hannachi
Abstract Empirical orthogonal functions (EOFs) are widely used in climate research to identify dominant patterns of variability and to reduce the dimensionality of climate data. EOFs, however, can be difficult to interpret. Rotated empirical orthogonal functions (REOFs) have been proposed as more physical entities with simpler patterns than EOFs. This study presents a new approach for finding climate patterns with simple structures that overcomes the problems encountered with rotation. The method achieves simplicity of the patterns by using the main properties of EOFs and REOFs simultaneously. Orthogonal patterns that maximise variance subject to a constraint that induces a form of simplicity are found. The simplified empirical orthogonal function (SEOF) patterns, being more ,local', are constrained to have zero loadings outside the main centre of action. The method is applied to winter Northern Hemisphere (NH) monthly mean sea level pressure (SLP) reanalyses over the period 1948,2000. The ,simplified' leading patterns of variability are identified and compared to the leading patterns obtained from EOFs and REOFs. Copyright © 2005 Royal Meteorological Society. [source]


York and its Region in the Eighth and Ninth Centuries AD: An Archaeological Study

OXFORD JOURNAL OF ARCHAEOLOGY, Issue 1 2001
John Naylor
The archaeological study of the early medieval economy, and especially the emporia, has traditionally focused on aspects of long-distance exchange. The paper highlights the need for a more regional focus, by assessing the role and impact of the emporia on the surrounding areas, using York and its region as the basis for the study. Coinage, pottery, and stone artefacts are examined through their regional distributions, and implications for trade and exchange (long-distance, regional and local) discussed. The concluding discussion suggests that York, whilst probably the main centre for long-distance trade, may have been only one of a number of trading centres, and that during the later eighth and ninth centuries, regional exchange may have become increasingly important with the rise of potential markets at a number of inland sites. [source]


Men born in the region of Leipzig (Saxony, Germany) between 1960 and 1970 showed a significantly decreased sperm count (examination of 3432 individuals)

ANDROLOGIA, Issue 6 2003
U. Paasch
Summary. The routine spermiogram parameters of 3432 patients born between 1952 and 1971 in the region of Leipzig were determined between January 1975 and March 2000. The patient group aged 24,35 years was characterized by low mobility and relocation living in the main centre of chemical industry with enormous environmental pollution in Eastern Germany up to 1990. Sperm concentrations and total sperm counts were found to be significantly reduced in men born between 1960 and 1970 compared with men born before this period (52.38 ± 1.21 versus 70.79 ± 2.15millions ml,1; 139.51 ± 3.66 versus 176.31 ± 6.04 millions; mean ± SEM; P < 0.01; 2410 versus 1022 patients) independently of the year of semen examination. [source]


ARCHSECRET: a multi-item scale to measure service quality within the voluntary sector

INTERNATIONAL JOURNAL OF NONPROFIT & VOLUNTARY SECTOR MARKETING, Issue 2 2001
Liz Vaughan
This paper provides an overview of the application of SERVQUAL reflecting the theoretical criticisms concerning disconfirmation model, process orientation, role of expectations and portability. The original SERVQUAL framework was found to be inappropriate for services that had no close analogue with the private sector. A qualitative research study was undertaken to establish the sector-specific criteria used by customers to evaluate service quality. The study identified 40 potentially unique features of the service as perceived by service recipients. These features were developed into a pilot survey instrument that comprised 40 questions, covering expectations, perceptions and importance. A pilot study was undertaken to test the instrument among disabled customers and their carers across the main centres of a national voluntary organisation. Analyses of the pilot survey data resulted in a set of 27 distinct statements across ten hypothesised service quality dimensions. These are Access, Responsiveness, Communication, Humaneness, Security, Enabling/Empowerment, Competence, Reliability, Equity, and Tangibles, giving rise to the acronym ARCHSECRET. The ARCHSECRET instrument is potentially a powerful diagnostic tool for managers in their pursuit of continuous quality improvement within voluntary sector organisations. Copyright © 2001 Henry Stewart Publications [source]


The settlement patterns of north-eastern and south-eastern Arabia in late antiquity

ARABIAN ARCHAEOLOGY AND EPIGRAPHY, Issue 2 2009
Michel Mouton
The east Arabian settlements in antiquity were never large urban sites. However, they were the main centres of the communities that inhabited that area, interfacing between the nomadic and sedentary societies. A study of the distribution and characteristics of these sites reveals different, complementary functions. They were organized in local networks forming the essential structure of the settlement pattern and delineating the territories of communities having their own political identity. [source]


A Survey of Portuguese Mathematics in the Nineteenth Century

CENTAURUS, Issue 4 2000
Luis M. Ribeiro Saraiva
Résumé La reforme de l'Université Portugaise en 1772, qui avait pour but la mettre au niveau des meilleures Universités d'Europe, n'a pas eu le temps de se développer, opposée par des forces rétrogrades. En conséquence de ce fait et du climat d'agitation politique et sociale qui a caractérisé la Portugal dans la première moitié du dixneuvième siècle, la production mathématique dans cette époque fut minimale. Les académies militaires étaient alors les principaux centres de transmission des connaissances mathématiques, et les articles de mathématique en ce temps étaient publiés dans sa majorité par l'Académie de Sciences de Lisbonne. Dans la deuxième moitié du dixneuvième siècle le Portugal entra dans une période de stabilité. La reforme de l'enseignement de 1836, et les nouveaux status de l'Académie de 1851 ont proporcionné un développement de l'activité mathématique, qui fut acompagnée de la restructuration des académies militaires ou de leur transformation en Ecoles Polytechniques; l'Ecole Polytechnique de Lisbonne fut spécialement importante. A partir de 1877, avec la publication du premier journal de mathématique qui ne dépendait pas de l'Académie, et qui avait pour but spécifique briser l'isolement des mathématiques portugaises, la recherche en ce champs s'est encore plus développée. Dans la dernière partie de cet article nous donnons quelques éléments sur la vie et l'oeuvre de deux importants mathématiciens portugais du dixneuvième siècle: Daniel Augusto da Silva (1814,1878) et Francisco Gomes Teixeira (1851,1933). Abstract The Portuguese University was briefly reformed in 1772, aiming to bring it to the level of its European counterparts; but this was soon cut short by the return to power of reactionary forces. As a consequence of this, and the political and social unrest that characterized the first half of the nineteenth century in Portugal, there was very little production of mathematics in this period. The military academies were the main centres of transmission of mathematical knowledge, and mathematical works were mostly published by the Lisbon Academy of Sciences. In the second half of the nineteenth century the country entered a period of stability. The education reform of 1836 and the Academy's new statutes of 1851 set in train a blossoming of mathematical activity, reflected in the restructuring of the military academies, or their transformation into Polytechnic Schools, of which the Polytechnic School of Lisbon is of particular importance. Mathematics research was further promoted from 1877 onwards by the publication of the first mathematics journal independent of the Academy, which aimed specifically at ending the isolation of Portuguese mathematics. In the final pages of this survey some data is given on the life and work of the two outstanding Portuguese mathematicians of the nineteenth century: Daniel Augusto da Silva (1814,1878) and Francisco Gomes Teixeira (1851,1933). [source]