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Holmstrm L.,University of Oulu | Pasanen L.,University of Oulu | Furrer R.,University of Zrich | Sain S.R.,U.S. National Center for Atmospheric Research
Computational Statistics and Data Analysis

A method to capture the scale-dependent features in a random signal is proposed with the main focus on images and spatial fields defined on a regular grid. A technique based on scale space smoothing is used. However, while the usual scale space analysis approach is to suppress detail by increasing smoothing progressively, the proposed method instead considers differences of smooths at neighboring scales. A random signal can then be represented as a sum of such differences, a kind of a multiresolution analysis, each difference representing details relevant at a particular scale or resolution. Bayesian analysis is used to infer which details are credible and which are just artifacts of random variation. The applicability of the method is demonstrated using noisy digital images as well as global temperature change fields produced by numerical climate prediction models. © 2011 Elsevier B.V. All rights reserved. Source

Ihrler S.,Ludwig Maximilians University of Munich | Rath C.,Ludwig Maximilians University of Munich | Rath C.,University of Zrich | Zengel P.,Ludwig Maximilians University of Munich | And 3 more authors.
Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology and Endodontology

Objectives: The pathogenesis of acinar enlargement in sialadenosis is obscure. As myoepithelial cells had been reported to show degenerative changes, we decided to investigate the possible role of functionally deficient myoepithelial cells in the development of sialadenosis. Study design: This study was a morphometric analysis of glands immunohistochemically stained for CK14, α-actin, and Ki67 in 10 cases of sialadenosis and 11 normal parotids. Results: In sialadenosis, acini were much larger; there was a minor decrease in the density of the distribution of myoepithelial cells stained for CK14 and a major decrease in the density of the distribution and thickness of the myofilament component of myoepithelial cells stained for α-actin; and the proliferation of acinar and myoepithelial cells was reduced. Conclusions: Our results demonstrate a major loss and thinning of the myofilament component of the myoepithelial cells and thereby a loss of mechanical support for the acini in sialadenosis. This possibly allows acinar cells to expand as secretory granules accumulate intracellularly to produce the great acinar enlargement. This functional myoepithelial insufficiency is possibly a consequence of an autonomic neuropathy secondary to severe metabolic or hormonal disorders. © 2010 Mosby, Inc. Source

Djagoun C.A.M.S.,University Abomey Calavi | Codron D.,Florisbad Quaternary Research | Codron D.,University of Zrich | Sealy J.,University of Cape Town | And 3 more authors.
South African Journal of Wildlife Research

Bovid diets have been studied for decades, but debate still exists about the diets of many species, in part because of geographical or habitat-related dietary variations. In this study we used stable carbon isotope analyses of faeces to explore the seasonal dietary preferences of 11 bovid species from a West African savanna, the Pendjari Biosphere Reserve (PBR), along the browser/grazer (or C3/C4) continuum.We compare our carbon isotope values with those for eastern and southern African bovids, as well as with dietary predictions based on continent-wide averages derived from field studies. Oribi and reedbuck, expected to be grazers were found to be predominantly C3-feeders (browsers) in the PBR. Bushbuck, common duiker and red-flanked duiker consumed more C4 grass than reported in previous studies. When comparing wet and dry season diets, kob, roan and oribi showed the least variation in C3 and C4 plant consumed proportions, while red-flanked duiker, bushbuck, reedbuck and waterbuck showed the most marked shifts. This study shows that animals in the betterstudied eastern and southern African savannas do not exhibit the full range of possible dietary adaptations. Inclusion of data from a wider geographical area to include less well-studied regions will inform our overall picture of bovid dietary ecology. Source

Middelboe M.,Copenhagen University | Glud R.N.,University of Southern Denmark | Glud R.N.,Greenland Institute of Natural Resources | Glud R.N.,Scottish Association for Marine Science | And 2 more authors.
Aquatic Microbial Ecology

Subsurface abundance and distribution of viruses and prokaryotes was determined along a depth profile, down to 96 m below seafloor (96 mbsf), at Challenger Mound from the Porcubine Seabight (IODP Expedition 307). Viral and prokaryotic abundance decreased exponentially with sediment depth from 1.0 × 108 viruses cm-3 and 3.8 × 106 cells cm-3 at 4 mbsf to 4.9 × 106 viruses cm-3 and 9.8 × 105 cells cm-3 at 96 mbsf. The age of the sediment ranges from ca. 0.5 million yr before present (Ma) at 4 mbsf to ca. 2 Ma at 96 mbsf. Assuming that the decline in viral abundance with depth reflects a gradual decay of the viral assemblage over time, the estimated decay rate of the viral community is 1.2 × 10-6 ± 0.3 × 10 -6 (SD) yr-1, corresponding to a half-life of the viral community of 5.8 × 105 yr. Measurements of viral and prokaryotic change in abundance were performed in incubations of undiluted, but homogenized, sediment samples (13.3 and 79.8 mbsf) in anaerobic bags. Viral abundance decreased rapidly (decay rates of 0.010 ± 0.002 [SD] and 0.022 ± 0.018 [SD] h--1, respectively) in the incubations, suggesting that homogenization exposed the viruses to degradation processes. We hypothesize that most of the deep subsurface viral communities inhabit a microenvironment where the viruses are protected against decay, and can therefore persist in undisturbed sediments for hundreds of thousands, perhaps even millions, of years. © Inter-Research 2011. Source

Akinde M.,Norwegian Meteorological Institute | Bhlen M.H.,University of Zrich | Chatziantoniou D.,Athens University of Economics and Business | Gamper J.,Free University of Bozen Bolzano
Information Systems

The SQL:2003 standard introduced window functions to enhance the analytical processing capabilities of SQL. The key concept of window functions is to sort the input relation and to compute the aggregate results during a scan of the sorted relation. For multi-dimensional OLAP queries with aggregation groups defined by a general θ condition an appropriate ordering does not exist, though, and hence expensive join-based solutions are required. In this paper we introduce θconstrained multi-dimensional aggregation (θMDA), which supports multi-dimensional OLAP queries with aggregation groups defined by inequalities. θMDA is not based on an ordering of the data relation. Instead, the tuples that shall be considered for computing an aggregate value can be determined by a general θ condition. This facilitates the formulation of complex queries, such as multi-dimensional cumulative aggregates, which are difficult to express in SQL because no appropriate ordering exists. We present algebraic transformation rules that demonstrate how the θMDA interacts with other operators of a multi-set algebra. Various techniques for achieving an efficient evaluation of the θMDA are investigated, and we integrate them into concrete evaluation algorithms and provide cost formulas. An empirical evaluation with data from the TPC-H benchmark confirms the scalability of the θMDA operator and shows performance improvements of up to one order of magnitude over equivalent SQL implementations. © 2010 Elsevier B.V. All rights reserved. Source

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