705 research outputs found

    Cross Recurrence Plot Based Synchronization of Time Series

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    The method of recurrence plots is extended to the cross recurrence plots (CRP), which among others enables the study of synchronization or time differences in two time series. This is emphasized in a distorted main diagonal in the cross recurrence plot, the line of synchronization (LOS). A non-parametrical fit of this LOS can be used to rescale the time axis of the two data series (whereby one of it is e.g. compressed or stretched) so that they are synchronized. An application of this method to geophysical sediment core data illustrates its suitability for real data. The rock magnetic data of two different sediment cores from the Makarov Basin can be adjusted to each other by using this method, so that they are comparable.Comment: Nonlinear Processes in Geophysics, 9, 2002, in pres

    Sedimentation rates in the Makarov Basin, central Arctic Ocean: A paleomagnetic and rock magnetic approach

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    Three long sediment cores from the Makarov Basin have been subjected to detailed paleomagnetic and rock magnetic analyses. Investigated sediments are dominated by normal polarity including short reversal excursions, indicating that most of the sediments are of Brunhes age. In general, the recovered sediments show only low to moderate variability in concentration and grain size of the remanence-carrying minerals. Estimations of relative paleointensity variations yielded a well-documented succession of pronounced lows and highs that could be correlated to published reference curves. However, together with five accelerator mass spectrometry C-14 ages and an incomplete Be-10 record, still two different interpretations of the paleomagnetic data are possible, with long-term sedimentation rates of either 1.3 or 4 cm kyr(-1) However, both models implicate highly variable sedimentation rates of up to 10 cm kyr(-1), and abrupt changes in rock magnetic parameters might even indicate several hiatuses

    Histological, histochemical and fine structure studies of the lacrimal gland and superficial gland of the third eyelid and their significance on the proper function of the eyeball in alpaca (Vicugna pacos)

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    The lacrimal gland (LG) and superficial gland of the third eyelid (SGTE) belong to accessory organs of the eye. The aim of the present studies was to evaluate the histological, histochemical and fine structure of the LG and SGTE obtained from 3 adult females and 2 adult males of alpaca (Vicugna pacos). The LG was situated in the dorsolateral angle of the orbit between the dorsal rectus and the lateral rectus muscles. The SGTE was located between the medial rectus muscle, the ventral rectus muscle and was partially covered by the ventral oblique muscle of the eyeball. There were no effect of gender on the morphometry of examined LG and SGTE. The third eyelid resembles an anchor in shape. During histological and ultrastructural analyses using light and transmission electron microscopy, it was established that the LG and SGTE are tubulo-acinar glands with mucoserous characters. The LG contains either lymphocytes or plasma cells, while SGTE had rare plasma cells and numerous lymphocytes in connective tissue. The cartilage of the third eyelid was composed of hyaline tissue. Numerous aggregations of lymphocytes as lymph nodules in bulbar surface of the third eyelid were observed. The LG and SGTE secretory cells exhibited a similar ultrastructure appearance in electron microscopic examination, with secretory cells tightly filled with intracytoplasmatic secretory granules and numerous clusters of mucus of different sizes which were observed in the peripheral cells compartment

    26 Ocena wyników pooperacyjnej radioterapii skojarzonej z 5-fluorouracylem u chorych na raka odbytnicy

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    Celem pracy była ocena wyników leczenia uzupełniającego z udziałem chemio- i radioterapii chorych po radykalnym zabiegu operacyjnym z powodu raka odbytnicy, ze szczególnym uwzględnieniem tolerancji leczenia. Materiał obejmuje 64 chorych leczonych w Klinice Onkologii i Radioterapii w Iatach1991–1995. Głównymi powikłaniami w czasie leczenia były biegunki (58%), nudności i wymioty (15%), objawy dyżuryczne (6%), leukopenia (33%) i niedokrwistość (5%). Do ostrych powikłań doszło ogółem 43 chorych (66%) w tym u 15 (23%) miały one charakter ciężki (stopień III i IV). Troje chorych nie ukończyło leczenia z powodu znacznego nasilenia objawów niepożądanych leczenia i pogorszenia stanu ogólnego.Późne powikłania, przede wszystkim w obrębie jelit i dróg moczowych, wystąpiły ogółem u 22 chorych (34%) w tym u 6 (9%)- w stopniu ciężkim. Spośród ocenionych 64 chorych dotychczas zmarło 19 (30%). Mediana czasu przeżycia w całej grupie wynosiła 37 miesięcy (11–60 miesięcy). Do wznowy miejscowej doszło u 15 chorych (23%) natomiast przerzuty odległe wystąpiły u 18 chorych (28%). Przedstawione wyniki, wskazujące na wysoki odsetek nawrotów oraz dużą liczbę powikłań popromiennych, skłoniły nas do zmiany techniki napromieniania. Efekty tych modyfikacji będzie można ocenić dopiero za kilka lat

    Domain-wall dynamics in 4C pyrrhotite at low temperature

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    Monoclinic 4C pyrrhotite (Fe7S8) is ferrimagnetic due to an ordered defect structure with alternating vacancy and vacancy-free sublattices. Its low-temperature magnetic transition near 35 K is characterized by the distinct increase in coercivity and remanent magnetization. The increase of these parameters has been attributed to changes in the domain wall structure. We present static and dynamic magnetization data of a powder sample to study the domain-wall dynamics across the low-temperature transition. The amplitude-dependent ac susceptibility and the ferromagnetic resonance spectroscopy indicate that the hardening of the domain-wall pinning at the transition occurs simultaneously with the decrease in initial saturation remanent magnetization. These two effects are explained by the enhanced inhomogeneity of the bulk material caused by the persistency of the ordered vacancies and by newly formed defects due to localized distortion of Fe(II) sites in the vacancy-free sublattice. The generated localized defects are the link between the domain wall dynamics and the low-temperature transition in 4C pyrrhotit

    Environmental control on the occurrence of high-coercivity magnetic minerals and formation of iron sulfides in a 640 ka sediment sequence from Lake Ohrid (Balkans)

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    The bulk magnetic mineral record from Lake Ohrid, spanning the past 637 kyr, reflects large-scale shifts in hydrological conditions, and, superimposed, a strong signal of environmental conditions on glacial–interglacial and millennial timescales. A shift in the formation of early diagenetic ferrimagnetic iron sulfides to siderites is observed around 320 ka. This change is probably associated with variable availability of sulfide in the pore water. We propose that sulfate concentrations were significantly higher before  ∼  320 ka, due to either a higher sulfate flux or lower dilution of lake sulfate due to a smaller water volume. Diagenetic iron minerals appear more abundant during glacials, which are generally characterized by higher Fe / Ca ratios in the sediments. While in the lower part of the core the ferrimagnetic sulfide signal overprints the primary detrital magnetic signal, the upper part of the core is dominated by variable proportions of high- to low-coercivity iron oxides. Glacial sediments are characterized by high concentration of high-coercivity magnetic minerals (hematite, goethite), which relate to enhanced erosion of soils that had formed during preceding interglacials. Superimposed on the glacial–interglacial behavior are millennial-scale oscillations in the magnetic mineral composition that parallel variations in summer insolation. Like the processes on glacial–interglacial timescales, low summer insolation and a retreat in vegetation resulted in enhanced erosion of soil material. Our study highlights that rock-magnetic studies, in concert with geochemical and sedimentological investigations, provide a multi-level contribution to environmental reconstructions, since the magnetic properties can mirror both environmental conditions on land and intra-lake processes

    Putative Cooperative ATP-DnaA Binding to Double-Stranded DnaA Box and Single-Stranded DnaA-Trio Motif upon Helicobacter pylori Replication Initiation Complex Assembly

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    oriC is a region of the bacterial chromosome at which the initiator protein DnaA interacts with specific sequences, leading to DNA unwinding and the initiation of chromosome replication. The general architecture of oriCs is universal; however, the structure of oriC and the mode of orisome assembly differ in distantly related bacteria. In this work, we characterized oriC of Helicobacter pylori, which consists of two DnaA box clusters and a DNA unwinding element (DUE); the latter can be subdivided into a GC-rich region, a DnaA-trio and an AT-rich region. We show that the DnaA-trio submodule is crucial for DNA unwinding, possibly because it enables proper DnaA oligomerization on ssDNA. However, we also observed the reverse effect: DNA unwinding, enabling subsequent DnaA–ssDNA oligomer formation—stabilized DnaA binding to box ts1. This suggests the interplay between DnaA binding to ssDNA and dsDNA upon DNA unwinding. Further investigation of the ts1 DnaA box revealed that this box, together with the newly identified c-ATP DnaA box in oriC1, constitute a new class of ATP–DnaA boxes. Indeed, in vitro ATP–DnaA unwinds H. pylori oriC more efficiently than ADP–DnaA. Our results expand the understanding of H. pylori orisome formation, indicating another regulatory pathway of H. pylori orisome assembly
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