Diagonalization of matrices over graded principal ideal domains

AbstractThe main result of this paper is the analogue of the classical diagonal reduction of matrices over PIDs, for graded principal ideal domains. A method for diagonalizing graded matrices over a graded principal ideal domain is obtained. In Section 2 we emphasis on some applications. A procedure is given to decide whether or not a matrix defined over an ordinary Dedekind domain (i.e. nongraded), with cyclic class group, is diagonalizable. In case the answer is positive the diagonal form can be calculated. This can be done by taking a suitable graded PID which has the Dedekind domain as its part of degree zero. It turns out that, even in the case where diagonalization of a matrix over the part of degree zero is not possible, the diagonal representation over the graded ring contains useful information. The main reason for this is that the graded ring hasn't essentially more units than its part of degree zero. We illustrate this by considering the problem of von Neumann regularity of a matrix over a Gr-PID and to matrices over Dedekind domains with cyclic class group. These problems were the original motivation for studying diagonalization over graded rings

Rassenonderzoek witte asperge seizoen 2001-2002

In 2000 zijn twee nieuwe rassenproeven witte asperge aangelegd in Meterik, Nederland (PPO) en in Geel, België (PDLT). Er zijn 10 dezelfde rassen aangeplant op beide plaatsen. De rassen zijn gezaaid bij plantenkwekerij de Kemp in Meterik in 1999. Het sortiment bestaat uit de Hollandse rassen Backlim, Gijnlim, Thielim, Grolim afkomstig van Asparagus BV te Horst en de Duitse rassen Eposs, Ramada, Ramos, Ravel , Rally (96013) en Rapsody (96071) afkomstig van SWD Saatsucht. De Nederlandse rassen worden verkocht door Nunhem en de Duitse door Royal Sluis

Imaging dielectric relaxation in nanostructured polymers by frequency modulation electrostatic force microscopy

We have developed a method for imaging the temperature-frequency dependence of the dynamics of nanostructured polymer films with spatial resolution. This method provides images with dielectric compositional contrast well decoupled from topography. Using frequency-modulation electrostatic-force-microscopy, we probe the local frequency-dependent (0.1–100 Hz) dielectric response through measurement of the amplitude and phase of the force gradient in response to an oscillating applied electric field. When the phase is imaged at fixed frequency, it reveals the spatial variation in dielectric losses, i.e., the spatial variation in molecular/dipolar dynamics, with 40 nm lateral resolution. This is demonstrated by using as a model system; a phase separated polystyrene/polyvinyl-acetate (PVAc) blend. We show that nanoscale dynamic domains of PVAc are clearly identifiable in phase images as those which light-up in a band of temperature, reflecting the variations in the molecular/dipolar dynamics approaching the glass transition temperature of PVAc

Modern and fossil non-pollen palynomorphs from the Basque mountains (western Pyrenees, France): the use of coprophilous fungi to reconstruct pastoral activity

International audienceThis paper presents results from a modern dataset of non-pollen palynomorphs and its application to aca. 2,000 year peat record from the same area in the western Pyrenees (Basque Country, France). The modern dataset is composed of 35 surface samples (moss polsters) from a mountainous pasture-woodland landscape. Airborne fungal spores (ascospores and conidia), found dominant in the dataset, are linked to the degree of landscape openness and grazing pressure. The complete spectrum of 13 selected spore-types of dung-related Ascomycetes is positively linked with grazing pressure. However, different dung affinities between the spore-types have been identified. These are types clearly related to high grazing pressure and types with no or unclear dung indicative value. The modern dataset is used to aid interpretation of the local fossil pollen record as an independent 'proxy' to assess past pastoral dynamics. This study confirms the utility of modern nonpollen palynomorphs from terrestrial ecosystems in the reconstruction of historical local pastoral activities but also shows their limitation. It may be necessary to extend such study to wetland ecosystems and to investigate the spatial dimension of some fungal spores

A Novel Connexin 26 Mutation in a Patient Diagnosed with Keratitis–Ichthyosis–Deafness Syndrome

Keratitis–ichthyosis–deafness syndrome is a rare disorder characterized by erythrokeratoderma, deafness, and keratitis. Scarring alopecia and squamous cell carcinoma can also occur. Most cases described so far were sporadic. Here we present evidence that keratitis–ichthyosis–deafness syndrome is caused by a mutation in the connexin 26 gene. This finding expands the spectrum of disorders caused by defects in connexin 26 and implies the gene in normal corneal function, hair growth, and carcinogenesis

Primary leiomyosarcoma of the adrenal gland

We report a rare case of a primary leiomyosarcoma of the adrenal gland. A 73-year-old woman presented with an inferior vena cava syndrome. MR imaging was suggestive of a large tumour originating from the right adrenal gland. Angiography revealed a tumour vascularised by the right adrenal artery. At explorative laparotomy a tumour of 27 cm in diameter was found which was completely fixed to the liver; the tumour was therefore considered unresectable. As a consequence of the mechanical problems caused by this large tumour, the patient died 3 weeks after the operation. Autopsy revealed no distant metastases or other primary tumour site.</p

Primary leiomyosarcoma of the adrenal gland

We report a rare case of a primary leiomyosarcoma of the adrenal gland. A 73-year-old woman presented with an inferior vena cava syndrome. MR imaging was suggestive of a large tumour originating from the right adrenal gland. Angiography revealed a tumour vascularised by the right adrenal artery. At explorative laparotomy a tumour of 27 cm in diameter was found which was completely fixed to the liver; the tumour was therefore considered unresectable. As a consequence of the mechanical problems caused by this large tumour, the patient died 3 weeks after the operation. Autopsy revealed no distant metastases or other primary tumour site.</p

The composition of serous fluid after axillary dissection

Objective: To analyse the composition of the serous fluid formed after axillary dissection Design: Descriptive study Setting: University hospital and teaching hospital, The Netherlands Subjects: 16 patients whose axillas were dissected as part of a modified radical mastectomy for stage I or II breast cancer. Main outcome measures: Chemical and cellular composition of axillary drainage fluid on the first, fifth, and tenth postoperative days compared with the same constituents in blood and with reported data on the composition of peripheral lymph. Results and conclusion: On the first postoperative day the drainage fluid contained blood contents and a high concentration of creatine phosphokinase (CPK). After day one it changed to a peripheral lymph-like fluid but containing different cells, more protein, and no fibrinogen, making coagulation impossible. The reduction in the fluid production must be caused by other wound healing processes, such as formation of scars and connective tissue