871 research outputs found

    Ceramics and Society in Northern Europe

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    Neolithic pottery in Britain and Ireland was produced from shortly after 4000 BC. There are regional variations but overall a four phase chronology for the pottery is also suggested: First Neolithic, approximately 4000–3800 BC; Early Neolithic, approximately 3800–3500 BC; Middle Neolithic, approximately 3500–2900 BC; and Late Neolithic, approximately 2900–2400 BC. Within this framework evidence for the processes of pottery production and use are studied to define a number of different traditions and practices. The external form of vessels seems to be strongly codified in the early part of the period, although there was a range of different inclusion recipes used. In the Middle and Later Neolithic there seem to be much simpler fabrics but a greater range of vessel shapes. This later pottery also seems to have been used for a much wider range of tasks

    Coherent many-body spin dynamics in a long-range interacting Ising chain

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    Coherent many-body quantum dynamics lies at the heart of quantum simulation and quantum computation. Both require coherent evolution in the exponentially large Hilbert space of an interacting many-body system. To date, trapped ions have defined the state of the art in terms of achievable coherence times in interacting spin chains. Here, we establish an alternative platform by reporting on the observation of coherent, fully interaction-driven quantum revivals of the magnetization in Rydberg-dressed Ising spin chains of atoms trapped in an optical lattice. We identify partial many-body revivals at up to about ten times the characteristic time scale set by the interactions. At the same time, single-site-resolved correlation measurements link the magnetization dynamics with inter-spin correlations appearing at different distances during the evolution. These results mark an enabling step towards the implementation of Rydberg atom based quantum annealers, quantum simulations of higher dimensional complex magnetic Hamiltonians, and itinerant long-range interacting quantum matter.Comment: 11 pages, 9 figure

    Invasion trajectory of Pacific oysters in the northern Wadden Sea

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    Invasion trajectories of introduced alien species usually begin with a long establishment phase of low abundance, often followed by exponential expansion and subsequent adjustment phases. We review the first 26 years of feral Pacific oysters Crassostrea gigas around the island of Sylt in the Wadden Sea (North Sea, NE Atlantic), and reveal causal conditions for the invasion phases. Sea-based oyster farming with repeated introductions made establishment of feral oysters almost inevitable. Beds of mussels Mytilus edulis on mud flats offered firm substrate for attachment and ideal growth conditions around low tide level. C. gigas mapped on to the spatial pattern of mussel beds. During the 1990s, cold summers often hampered recruitment and abundances remained low but oyster longevity secured persistence. Since the 2000s, summers were often warmer and recruitment more regular. Young oysters attached to adult oysters and abundances of >1000 m−2 were achieved. However, peak abundance was followed by recruitment failure. The population declined and then was also struck by ice winters causing high mortality. Recovery was fast (>2000 m−2) but then recruitment failed again. We expect adjustment phase will proceed with mean abundance of about 1000 m−2 but density-dependent (e.g., diseases) and density-independent (e.g., weather anomalies) events causing strong fluctuations. With continued global warming, feral C. gigas at the current invasion fronts in British estuaries and Scandinavian fjords may show similar adjustment trajectories as observed in the northern Wadden Sea, and also other marine introductions may follow the invasion trajectory of Pacific oysters

    ZMI - Newsletter 2/2005

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    Interaktive Wissenschaftskommunikation in digitalen Medien. * Kommunikations- und Informationsplattform "Partnerschaftsinitiative" - nachhaltige Entwicklungszusammenarbeit durch private Initiativen und Projekte. *AK eLearning: Strategiepapier zum eLearning an der JLU

    Effects of perioperative intravenous omega-3 fatty acids in colon cancer patients:a randomized, double-blind, placebo-controlled clinical trial

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    Background: The postoperative inflammatory response contributes to tissue healing and recovery but overwhelming inflammation is associated with postoperative complications. n-3 (ω-3) PUFAs modulate inflammatory responses and may help to prevent a proinflammatory cascade. Objectives: We aimed to investigate the effects of perioperative intravenous n-3 PUFAs on inflammatory cytokines in colon cancer surgery. Methods: This study is a randomized, double-blind, placebo-controlled clinical trial. Forty-four patients undergoing elective colon resection for nonmetastasized cancer were randomly assigned to 2 intravenous n-3 PUFA or saline control infusions the night before and the morning after surgery. Blood was sampled at 6 perioperative time points for changes in cytokines in serum and in LPS-stimulated whole blood samples and leukocyte membrane fatty acid profiles. Results: Twenty-three patients received saline and 21 patients received n-3 PUFAs. Patient and operation characteristics were equal between groups, except for open resection (saline n = 5 compared with n-3 PUFA n = 0, P = 0.056). Ex-vivo IL-6 after LPS stimulation was significantly higher in the n-3 PUFA group at the first day after surgery (P = 0.014), but not different at the second day after surgery (P = 0.467). White blood cell count was higher in the n-3 PUFA group at the fourth day after surgery (P = 0.029). There were more patients with infectious complications in the n-3 PUFA group (8 compared with 3, P = 0.036). There were no overall differences in serum IL-6, IL-10, C-reactive protein, and length of stay. The administration of n-3 PUFAs resulted in rapid increases in leukocyte membrane n-3 PUFA content. Conclusions: In the n-3 PUFA group a clear relation with serum and LPS-stimulated cytokines was not found but, unexpectedly, more infectious complications occurred. Caution is thus required with the off-label use of a perioperative intravenous n-3 PUFA emulsion as a standalone infusion in the time sequence reported in the present study in colon resections with primary anastomosis. This trial was registered at clinicaltrials.gov as NCT02231203

    Expression cloning and production of human heavy-chain-only antibodies from murine transgenic plasma cells

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    Several technologies have been developed to isolate human antibodies against different target antigens as a source of potential therapeutics, including hybridoma technology, phage and yeast display systems. For conventional antibodies, this involves either random pairing of VH and variable light (VL) domains in combinatorial display libraries or isolation of cognate pairs of VH and VL domains from human B cells or from transgenic mice carrying human immunoglobulin loci followed by single-cell sorting, single-cell RT-PCR, and bulk cloning of isolated natural VH-VL pairs. Heavy-chain-only antibodies (HCAbs) that naturally occur in camelids require only heavy immunoglobulin chain cloning. Here, we present an automatable novel, high-throughput technology for rapid direct cloning and production of fully human HCAbs from sorted population of transgenic mouse plasma cells carrying a human HCAb locus. Utility of the technique is demonstrated by isolation of diverse sets of sequence unique,soluble, high-affinity influenza A strain X-31 hemagglutinin-specific HCAbs

    Size Distributions of Coastal Ocean Suspended Particulate Inorganic Matter: Amorphous Silica and Clay Minerals and their Dynamics

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    Particulate inorganic matter (PIM) is a key component in estuarine and coastal systems and plays a critical role in trace metal cycling. Better understanding of coastal dynamics and biogeochemistry re-quires improved quantification of PIM in terms of its concentration, size distribution, and mineral species composition. The angular pattern of light scattering contains detailed information about the size and composition of particles. These volume scattering functions (VSFs) were measured in Mobile Bay, Alabama, USA, a dynamic, PIM dominated coastal environment. From measured VSFs, we determined through inversion the particle size distributions (PSDs) of major components of PIM, amorphous silica and clay minerals. An innovation here is the extension of our reported PSDs significantly into the sub-micron range. The PSDs of autochthonous amorphous silica exhibit two unique features: a peak centered at about 0.8mm between 0.2 and 4mm and a very broad shoulder essentially extending from 4mm to\u3e100mm. With an active and steady particle source from blooming diatoms, the shapes of amorphoussilica PSDs for sizes area, but showed more particles of sizes\u3e10mm inside the bay, likely due to wind-induced resuspension of larger frustules that have settled. Compared to autochthonous amorphous silica, the allochthonous clay minerals are denser and exhibit relatively narrower PSDs with peaks located between 1 and 4mm. Preferential settling of larger mineral particles as well as the smaller but denser illite component further narrowed the size distributions of clay minerals as they were being transported outside the bay. The derived PSDs also indicated a very dynamic situation in Mobile Bay when a cold weather front passed through during the experiment. With northerly winds of speeds up to 15 m s-1, both amorphous silica and clay minerals showed a dramatic increase in concentration and broadening in size distribution outside the exit of the barrier islands, indicative of wind-induced resuspension and subsequent advection of particles out of Mobile Bay. While collectively recognized as the PIM, amorphous silica and clay minerals, as shown in this study, possess very different size distributions. Considering how differences in PSDs and the associated particle areas will effect differences in sorption/desorption properties of these components, the results also demonstrate thepotential of applying VSF-inversion in studying biogeochemistry in the estuarine-coastal ocean system

    Ultrasonography of the Adrenal Gland

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    With appropriate techniques and using liver, spleen or kidney as an acoustic window, normal adrenal gland and adrenal lesions can be delineated by ultrasonography. The right adrenal gland is usually evaluated by transverse oblique scans and coronal scans, respectively, through the anterior and middle axillary line, while the left adrenal gland is investigated by an oblique coronal scan mainly through the posterior axillary line. For adrenal lesions, ultrasonography has a sensitivity of 74–97%, a specificity of 61–96%, and an accuracy of 70–97%. The diagnostic accuracy depends on the scanning technique and expertise of the operator, the body status of the patient, the size and functional status of the lesion, and the ultrasonographic quality. Small adrenal nodules, ileus, obesity, fatty liver, and large body status account for most of the reasons for decreased accuracy. Small adrenal nodules less than 3 cm in diameter mainly comprise functioning cortical adenomas, nonfunctioning cortical adenomas, nodular hyperplasia, and metastases. Most small adrenal masses are homogeneous and hypoechoic, and the echo patterns are nonspecific. Large adrenal masses greater than 3 cm in diameter mainly include primary adrenocortical carcinoma, lymphoma, metastasis, lymphoma, and pheochromocytoma. The echogenicity of a large adrenal mass may be hyperechoic and heterogeneous because of the higher incidence of necrosis and hemorrhage. Other uncommon adrenal masses are myelolipoma, hematoma, granulomatous lesions, hemangioma, and adrenal cysts of various origins. The differential diagnoses of a hyperechoic adrenal mass include neuroblastoma, myelolipoma, and tumor with central necrosis or heterogeneity. Calcification is encountered in both benign and malignant processes. It is sometimes difficult to differentiate benign adrenal masses from malignant lesions. Dynamic computed tomography, magnetic resonance imaging, and positron emission tomography play critical complementary roles in such an instance
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