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La adenosis poliquística esclerosante de la parótida (APEP) es una enfermedad infrecuente, caracterizada por elementos histológicos inflamatorios reactivos de las glándulas salivales, pero la presencia de displasia y atiplas hace también posible pensar se trate de un pseudotumor o una neoplasia. La APEP posee además semejanzas histopatológicas con la enfermedad fibroquística de la mama y comparten receptores de progesterona y estrógenos en las células ductales. La edad promedio de ocurrencia de esta patología es de 44,5 años y generalmente afecta las glándulas salivares mayores. Presentamos aquí el caso clínico de una mujer de 25 años de edad que el año 2002 consultó por un aumento de volumen de la parótida derecha, de larga data. Después de estudios diagnósticos y tratamientos fue intervenida quirúrgicamente y el análisis histopatológico sugirió el diagnóstico APEP. Sclerosing polycystic adenosis (SPA) of the parotid gland is a rare disease characterized histologically by a reactive inflammation of the salivary glands, although the presence of displasia and atypia raise the possibility that SPA might represent a neoplastic lesion. SPA bears histopathological resemblance to fibrocystic disease of the breast, and both glands show progesterone and oestrogen receptors in the ductal cells. The mean age of occurrence is 44.5 year-old, and it mostly affects major salivary glands. We report the case of a 25-years-old woman, who in 2002 presented with increased volume in the right parotid gland. After medical studies and several surgical treatments, the histopathological study revealed it to be SPA.

La adenosis poliquística esclerosante de la parótida (APEP) es una enfermedad infrecuente, caracterizada por elementos histológicos inflamatorios reactivos de las glándulas salivales, pero la presencia de displasia y atiplas hace también posible pensar se trate de un pseudotumor o una neoplasia. La APEP posee además semejanzas histopatológicas con la enfermedad fibroquística de la mama y comparten receptores de progesterona y estrógenos en las células ductales. La edad promedio de ocurrencia de esta patología es de 44,5 años y generalmente afecta las glándulas salivares mayores. Presentamos aquí el caso clínico de una mujer de 25 años de edad que el año 2002 consultó por un aumento de volumen de la parótida derecha, de larga data. Después de estudios diagnósticos y tratamientos fue intervenida quirúrgicamente y el análisis histopatológico sugirió el diagnóstico APEP.

Results of studying bottom deposits of Lake Naroch in Belarus are discussed. Six cores up to 5.88 m thick taken by a special corer that does not disturb the structure and integrity of sediments. All of the study cores showed good agreement between variations in the declination and inclination of the ChRM vector extracted by the alternating field (AF) demagnetization. Absolute ages of the sediments and the along-core time scales were obtained from 14C data and correlation with archaeomagnetic data from central Europe over the last 2000 years. The inferred data are used for constructing variation curves of inclination and declination in this region covering a 12-kyr period. The results are compared with paleovariations in geomagnetic field elements in Western Europe. A 700-year shift is discovered between the ages of magnetization and the sediments. The postdepositional magnetization smoothed the amplitudes of variations recorded in the sediments. Copyright © 2003 by MAIK "Nauka/Interperiodica" (Russia).

A detailed rock magnetic investigation of loess/palaeosol samples from the section at Lingtai on the central Chinese Loess Plateau (CLP) is presented. Thermal demagnetisation of isothermal remanent magnetisation (IRM) and Curie temperature measurements suggest the presence of magnetite, maghemite and hematite as remanence carrying components. Bulk and grain size fractionated samples have been analysed using coercivity spectra of remanence acquisition/demagnetisation curves, which identify four main remanence carriers in different grain size fractions of loesses and palaeosols. A linear source mixing model quantifies the contribution of the four components which have been experimentally derived as dominating endmembers in specific grain size fractions. Up to two thirds of the total IRM of the palaeosols are due to slightly oxidised pedogenic magnetite. Two detrital components dominate up to 90% of the IRM of the loess samples and are ascribed to maghemite of different oxidation degree. Detrital hematite is present in all samples and contributes up to 10% of the IRM. The iron content of the grain size fractions gives evidence that iron in pedogenically grown remanence carriers does not originate from the detrital iron oxides, but rather from iron-bearing clays and mafic silicates. The contribution of pedogenic magnetite to the bulk IRM increases with the increasing degree of pedogenesis, which depends in turn on climate change. © 2003 Elsevier B.V. All rights reserved.

A record of geomagnetic paleosecular variation (PSV) spanning the last ∼1200 years has been obtained from two lacustrine sediment cores from the north part of Aral Sea (Kazakhstan). Magnetic susceptibility and NRM intensity have been used for correlating between cores and reconstructing composite core data. The main swings and fine details of declination and inclination records correlate well between both cores. A very high sedimentation rate (up to 25 mm per year) due to recent tectonic activity of the region provides a very high resolution PSV record for the interval from 450 ± 100 years BP to 655 ± 65 years BP. The results which have been dated by eight AMS radiocarbon age determinations, suggest that a 200-400 years secular variation period with amplitudes in declination and inclination up to 10-15° existed regularly during the time interval 0-1200 BP. Amplitudes of the PSV record from Aral Sea are not reduced and smoothed by postdetrital magnetization processes. They adjoin to the historical data model and are considered to represent a reliable paleosecular variation record for the Aral Sea region for the last ∼1200 years.

A methodology is proposed, which gives information about the contents of ferrimagnetic and antiferromagnetic minerals with different domain structure in soils and sediments. Isothermal remanent magnetisation (IRM) acquired and measured both at room temperature and at low temperature (77K) provides data which define a set of new parameters: AIRMlc provides information about the fraction of superparamagnetic ferrimagnetics in the studied samples; parameters C and g, respectively, inform about absolute and relative contents of goethite, and parameters B and b discern the fraction of goethite, in superparamagnetic state. The proposed methodology is applied to the study of cave sediments from the palaeo-anthropological site of Atapuerca

A magnetostratigraphic study has been performed on the paleontologically well constrained pelagic Middle Triassic (Lower/Upper Ladinian boundary) section at Margon (Trento, Southern Alps, Italy). Rock magnetic investigations indicate the presence of both high and low coercivity minerals. Specimens subjected to progressive thermal demagnetization procedures show that nearly all of them exhibit a low temperature magnetization component, parallel to the present-day field before bedding correction, and a high temperature one, characterized by either positive or negative and opposite polarity, considered as the characteristic Triassic magnetization. Comparison of the Margon magnetic polarity zonation with those of two coeval sections poses some problems when ammonoid- and conodont-based stratigraphies have to be correlated. However, a good correlation has been obtained for the recognized Middle Triassic ammonoid biozones in the Tethys realm. Valuable data for the construction of a standard magnetostratigraphic and paleontological scale have been provided by the results from the Margon section.

BioMetals, 10 (4), ISSN:0966-0844, ISSN:1572-8773

The Late Permian is characterized palaeomagnetically by the transition from the long-lasting Permo-Carboniferous reversed polarity superchron (PCRS; also called: Kiaman reversed superchron) to the subsequent Permo-Triassic mixed polarity superchron, often called Illawarra mixed polarity superchron. Many discussions have been devoted to the exact time of the onset of the Illawarra reversals. Apparently contradictory data have been obtained from magnetostratigraphic sediment successions formed in different environments in many regions of the world. These sediments have been dated using classical geological or palaeontological correlation methods without the possibility of absolute age control because volcanogenic materials are missing. Application of the local or regional stratigraphic schemes leads to difficulties and apparent diachronous age estimates of the end of the PCRS. This paper shows that in agreement with earlier investigations, the continental red beds of the Upper Permian Tatarian stage on the eastern Russian platform record the Kiaman/Illawarra boundary. The Illawarra reversal sequence measured in a type section at the Volga river can be correlated well with the corresponding polarity pattern found in the Tethyan realm if one assumes a longer duration of the Tatarian than previously suggested.

A magnetostratigraphic profile of the uppermost Tatarian (Upper Permian) of a section of continental sediments from Eastern Platform is presented. Around 300 samples across an Upper Permian sequence o f red beds Monastirskoje on the Volga River Valley (South-West of Tatarian, Russia) have been collected. The characteristic primary component defined nearly for all the examined samples has a normal as well as reversed polarity, therefore a clear polarity zonation Is defined. The fold test, carried out on samples collected In the nearby section of Titjuschin where the sediments are exposed in a fold structure, indicates that the characteristic magnetization pre-dates the folding, Se presenta el perfil magnetoestratigráflco del Tatariense (Pérmico Superior) de una sección de sedimentos continentales de la plataforma del Este. Se recogieron alrededor de 300 muestras a lo largo de una serie continua de red beds en Monastirskoje, en el valle del Volga, (Suroeste de Tataria, Rusia). La componente característica primaria en todas las muestras examinadas presenta tanto polaridad normal como invertida, por lo que se ha definido una clara secuencia de polaridad. Se ha llevado a cabo un test del pliegue en rocas próxima a la sección de Titjuschin donde los sedimentos han experimentado fuertes plegamientos, que ha indicado que la magnetización característica es previa al plegamiento

A paleomagnetic record of geomagnetic secular variation during the last 3500 yr has been obtained from three lake sediment cores from lake Aslikul in the western Pre-Ural region (Russia). Pollen data provide a time-scale and relative paleotemperatures which can be compared with radiocarbon dated paleotemperature data for this region. Magnetic susceptibility measurements have been used for correlation between cores and reconstruction of composite core data. The paleosecular variations which have been recorded in the lake Aslikul sediments are consistent with results from West-European lakes. Westward shifting inclination features are observed between the more western European and the Pre-Ural regions which have apparent age differences between 200 and 600 years resulting in drift rates which are of the order of 0.1 degrees/year.