10,806 research outputs found

    Permian 40Ar/39Ar ages for post-Variscan minor intrusions in the Iberian Range and Spanish Central System

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    40Ar/39Ar dating of biotite from a calc-alkaline gabbro stock NW of Loscos in the Iberian Range yielded a slightly disturbed gas release spectrum. It has an early Permian, 288.5 ± 1.4 Ma total gas age, interpreted as the minimum emplacement age. The 40Ar/39Ar apparent age of the gabbro agrees with the Autunian stratigraphic age of related volcanic rocks. 40Ar/39Ar step-heating dating of amphibole phenocrysts from an alkaline camptonite dyke ca. 4 km SE of El Hoyo de Pinares in the Sierra Guadarrama sector of the Spanish Central System yielded a mid-Permian 264 ± 3 Ma plateau age, interpreted as the emplacement age. The age is indistinguishable from published 40Ar/39Ar amphibole ages for N-S trending camptonite dykes from the western, Sierra de Gredos segment of the Central System. This suggests that the camptonite dykes from both sectors belong to the same generation

    The future (?) of effective protection

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    This paper aims at a comparative reading of some archaeological remains in the island of Sardinia, starting from a reflection on the UNESCO discipline, which introduces a hierarchy of cultural heritage based on the level of worthiness of protection and provides enhanced protection for the goods that are on its list. The main goal of the study is to investigate in parallel the application of this ‘selective appreciation’ on the actual context of the protection of the so-called ‘real cultural heritage’ (article 9 of the Italian Constitution). The study proceeds by comparing some important sites on the island having similar contextualization, but different strategies for protection: the Archaeological Park of Porto Torres, Su Nuraxi in Barumini, registered since 1997 in the World Heritage List of UNESCO, and the archaeological area of Neapolis (Oristano). From comparisons and analysis carried out in selected areas it was possible to focus attention on some critical aspects of the UNESCO rules and on contradictions between the operational guidelines and the objectives that the organization provides for the protection of property. In the wake of new reforms for the reorganization of the Ministry of Heritage, Culture and Tourism, the critical issues discussed in this paper appear even more evident in Sardinia. The idea of a ‘protection of the exceptional’ appears to reduce the opportunities of intervention, by isolating the evidence from its context and making the action of protection inadequate for the territory and for the same items contained therein

    The future (?) of effective protection

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    This paper aims at a comparative reading of some archaeological remains in the island of Sardinia, starting from a reflection on the UNESCO discipline, which introduces a hierarchy of cultural heritage based on the level of worthiness of protection and provides enhanced protection for the goods that are on its list. The main goal of the study is to investigate in parallel the application of this ‘selective appreciation’ on the actual context of the protection of the so-called ‘real cultural heritage’ (article 9 of the Italian Constitution). The study proceeds by comparing some important sites on the island having similar contextualization, but different strategies for protection: the Archaeological Park of Porto Torres, Su Nuraxi in Barumini, registered since 1997 in the World Heritage List of UNESCO, and the archaeological area of Neapolis (Oristano). From comparisons and analysis carried out in selected areas it was possible to focus attention on some critical aspects of the UNESCO rules and on contradictions between the operational guidelines and the objectives that the organization provides for the protection of property. In the wake of new reforms for the reorganization of the Ministry of Heritage, Culture and Tourism, the critical issues discussed in this paper appear even more evident in Sardinia. The idea of a ‘protection of the exceptional’ appears to reduce the opportunities of intervention, by isolating the evidence from its context and making the action of protection inadequate for the territory and for the same items contained therein

    Physical interaction between MYCN oncogene and polycomb repressive complex 2 (PRC2) in neuroblastoma: Functional and therapeutic implications

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    This article is made available through the Brunel Open Access Publishing Fund. © 2013 by The American Society for Biochemistry and Molecular Biology, Inc.CLU (clusterin) is a tumor suppressor gene that we have previously shown to be negatively modulated by the MYCN proto-oncogene, but the mechanism of repression was unclear. Here, we show that MYCN inhibits the expression of CLU by direct interaction with the non-canonical E box sequence CACGCG in the 5′-flanking region. Binding of MYCN to the CLU gene induces bivalent epigenetic marks and recruitment of repressive proteins such as histone deacetylases and Polycomb members. MYCN physically binds in vitro and in vivo to EZH2, a component of the Polycomb repressive complex 2, required to repress CLU. Notably, EZH2 interacts with the Myc box domain 3, a segment of MYC known to be essential for its transforming effects. The expression of CLU can be restored in MYCN-amplified cells by epigenetic drugs with therapeutic results. Importantly, the anticancer effects of the drugs are ablated if CLU expression is blunted by RNA interference. Our study implies that MYC tumorigenesis can be effectively antagonized by epigenetic drugs that interfere with the recruitment of chromatin modifiers at repressive E boxes of tumor suppressor genes such as CLU.SPARKS, The Neuroblastoma Society, a Wellcome Trust grant (to A. S.), and the Italian Association for Cancer Research

    Remarkable Presentation: Anaplastic Thyroid Carcinoma Arising from Chronic Hyperthyroidism

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    Background. Undifferentiated anaplastic carcinoma rarely develops from chronic hyperthyroidism. Although acute hyperthy- roidism can develop prior to anaplastic transformation, chronic hyperthyroidism was thought to be a protective measure against thyroid malignancy. Methods. A 79-year-old female presented acutely to the hospital with dyspnea. She had been taking methimazole for chronic hyperthyroidism due to toxic thyroid nodules, previously biopsied as benign. Upon admission, imaging showed tracheal compression, requiring a total thyroidectomy with tracheostomy for airway management. Results. Pathology demonstrated undifferentiated anaplastic thyroid carcinoma. The patient passed away shortly after hospital discharge. Despite treatment with methimazole for many years, abrupt enlargement of her toxic multinodular goiter was consistent with malignant transformation. Chronic hyperthyroidism and toxic nodules are rarely associated with thyroid malignancy, with only one previous report documenting association with anaplastic thyroid carcinoma. Conclusion. Progressive thyroid enlargement and acute worsening of previously controlled hyperthyroidism should promote concern for disease regardless of baseline thyroid function

    Novel synthetic approach to heteroatom doped polycyclic aromatic hydrocarbons: Optimizing the bottom-up approach to atomically precise doped nanographenes

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    The success of the rational bottom-up approach to nanostructured carbon materials and the discovery of the importance of their doping with heteroatoms puts under the spotlight all synthetic organic approaches to polycyclic aromatic hydrocarbons. The construction of atomically precise heteroatom doped nanographenes has evidenced the importance of controlling its geometry and the position of the doping heteroatoms, since these parameters influence their chemical–physical properties and their applications. The growing interest towards this research topic is testified by the large number of works published in this area, which have transformed a once “fundamental research” into applied research at the cutting edge of technology. This review analyzes the most recent synthetic approaches to this class of compounds

    Spinfoams in the holomorphic representation

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    We study a holomorphic representation for spinfoams. The representation is obtained via the Ashtekar-Lewandowski-Marolf-Mour\~ao-Thiemann coherent state transform. We derive the expression of the 4d spinfoam vertex for Euclidean and for Lorentzian gravity in the holomorphic representation. The advantage of this representation rests on the fact that the variables used have a clear interpretation in terms of a classical intrinsic and extrinsic geometry of space. We show how the peakedness on the extrinsic geometry selects a single exponential of the Regge action in the semiclassical large-scale asymptotics of the spinfoam vertex.Comment: 10 pages, 1 figure, published versio
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