990 resultados para Berkeley Pit


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The POU transcription factor Pit-1 activates members of the prolactin/growth hormone gene family in specific endocrine cell types of the pituitary gland. Although Pit-1 is structurally conserved among vertebrate species, evolutionary changes in the pattern of Pit-1 RNA splicing have led to a notable "contraction" of the transactivation domain in the mammalian lineage, relative to Pit-1 in salmonid fish. By site-directed mutagenesis we demonstrate that two splice insertions in salmon Pit-1, called beta (29 aa) and gamma (33 aa), are critical for cooperative activation of the salmon prolactin gene. Paradoxically, Pit-1-dependent activation of the prolactin gene in rat is enhanced in the absence of the homologous beta-insert sequence. This apparent divergence in the mechanism of activation of prolactin genes by Pit-1 is target gene specific, as activation of rat and salmon growth hormone genes by Pit-1 splice variants is entirely conserved. Our data suggest that efficient activation of the prolactin gene in the vertebrate pituitary has significantly constrained the pattern of splicing within the Pit-1 transactivation domain. Rapid evolutionary divergence of prolactin gene function may have demanded changes in Pit-1/protein interactions to accommodate new patterns of transcriptional control by developmental or physiological factors.

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A novel OTX-related homeodomain transcription factor has been identified on the basis of its ability to interact with the transactivation domain of the pituitary-specific POU domain protein, Pit-1. This factor, referred to as P-OTX (pituitary OTX-related factor), is expressed in primordial Rathke's pouch, oral epithelium, first bronchial arch, duodenum, and hindlimb. In the developing anterior pituitary, it is expressed in all regions from which cells with distinct phenotypes will emerge in the mature gland. P-OTX is able to independently activate and to synergize with Pit-1 on pituitary-specific target gene promoters. Therefore, P-OTX may subserve functions in generating both precursor and specific cell phenotypes in the anterior pituitary gland and in several other organs.

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We present UBV photometry of the highly reddened and poorly studied open cluster Berkeley 55, revealing an important population of B-type stars and several evolved stars of high luminosity. Intermediate-resolution far-red spectra of several candidate members confirm the presence of one F-type supergiant and six late supergiants or bright giants. The brightest blue stars are mid-B giants. Spectroscopic and photometric analyses indicate an age 50 ± 10 Myr. The cluster is located at a distance d ≈ 4 kpc, consistent with other tracers of the Perseus Arm in this direction. Berkeley 55 is thus a moderately young open cluster with a sizable population of candidate red (super)giant members, which can provide valuable information about the evolution of intermediate-mass stars.

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Context. It appears that most (if not all) massive stars are born in multiple systems. At the same time, the most massive binaries are hard to find owing to their low numbers throughout the Galaxy and the implied large distances and extinctions. Aims. We want to study LS III +46 11, identified in this paper as a very massive binary; another nearby massive system, LS III +46 12; and the surrounding stellar cluster, Berkeley 90. Methods. Most of the data used in this paper are multi-epoch high S/N optical spectra, although we also use Lucky Imaging and archival photometry. The spectra are reduced with dedicated pipelines and processed with our own software, such as a spectroscopic-orbit code, CHORIZOS, and MGB. Results. LS III +46 11 is identified as a new very early O-type spectroscopic binary [O3.5 If* + O3.5 If*] and LS III +46 12 as another early O-type system [O4.5 V((f))]. We measure a 97.2-day period for LS III +46 11 and derive minimum masses of 38.80 ± 0.83 M⊙ and 35.60 ± 0.77 M⊙ for its two stars. We measure the extinction to both stars, estimate the distance, search for optical companions, and study the surrounding cluster. In doing so, a variable extinction is found as well as discrepant results for the distance. We discuss possible explanations and suggest that LS III +46 12 may be a hidden binary system where the companion is currently undetected.

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Berkeley’s general tenet about immaterialism is presented and discussed. I examined apart the several theses that concur to the immaterialist theory. After that, the general argument is presented and discussed. In particular, I stress Berkeley’s assumption that a world without matter and a world with matter would be indistinguishable from the point of view of (i) the content of perceptions, (ii) natural science (viz. Newtonian mechanics). I stress that this assumption depends on a relative account of circular motion, generating the centrifugal forces, as Newton shows in his bucket experiment. In spite of the efforts by Leibniz and Huygens, such a relative account of rotational motion was never presented. So the thesis about the scientific and perceptual identity between worlds with and without matter remains a simple case of wishful thinking in need for a justification.

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The annexation of Crimea has brought the Russian authorities significant dividends, in particular on the domestic stage: it has resulted in an unprecedented social and political consolidation, and strengthened Vladimir Putin’s position after several years of decline in social support for him. It has provided Russia with strategic benefits, giving it broad access to the Black Sea and the military infrastructure on the peninsula, as well as access to natural gas and crude oil reserves. Russia has also taken over numerous assets (including the tourist infrastructure) previously owned by the Ukrainian state. However, the decision itself concerning Moscow’s annexation of Crimea was taken off the cuff, with no calculation of the costs of integrating it with the Russian legal, political and socio-economic space. Russia took over a region that required subsidies from the Ukrainian budget; moreover, the annexation struck at the most important industry of the Crimean economy – tourism. Crimea’s integration with Russia will be a complex process that entails high costs, financial, organisational and social, including multi-billion dollar investments in the modernisation and development of infrastructure, covering the region’s budget deficit, and paying out social benefits. For reasons of prestige and political significance, Moscow is treating Crimea as a showcase region. Russia is determined to prove that the Crimean incorporation will be beneficial for the region’s economy and will raise people’s living standards. However, the expenses triggered by Crimea’s integration will coincide with a deteriorating economic situation in Russia, aggravated by US and EU sanctions, and this may force Russia to postpone or even give up some of its ambitious investments in the peninsula. Some of the integration costs will have to be borne by other Russian regions, even though they already face serious financial problems that have forced them to reduce their own investment programs. Another issue that has come into question is the fulfilment of the Crimean people’s’ expectations concerning the improvement of their living standards, due to the tourist sector’s problems (small-scale tourist services used to be one of the local people’s main sources of income), the rising costs of maintenance, and finally, restrictions of civil rights after the introduction of the more restrictive Russian legislation.

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Includes bibliographic references.

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5 proof sheets of an unidentified student protest at Berkeley

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Mode of access: Internet.

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"Originally presented under the title 'New light on Berkeley's American sojourn', at the commemoration of the two hundredth anniversary of Dean Berkeley's arrival in America ... held at the Berkeley divinity school in New Haven ... on January 23, 1929."--Pref.

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Absorbed Directory of cement, gypsum, lime, sand, gravel and crushed-stone plants in 1930 and assumed its volume numbering.