933 resultados para Tie Breaking


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We elaborate on a recent study of a model of supersymmetry breaking we proposed recently, in the presence of a tunable positive cosmological constant, based on a gauged shift symmetry of a string modulus, external to the Standard Model (SM) sector. Here, we identify this symmetry with a global symmetry of the SM and work out the corresponding phenomenology. A particularly attracting possibility is to use a combination of Baryon and Lepton number that contains the known matter parity and guarantees absence of dimension-four and -five operators that violate B and L.

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The mutinies of the Continental Army during the American Revolution threatened both the integrity of the army and the viability of the Revolution itself. They were complex phenomena, stemming from numerous underlying physical and psychological causes. Having slowly developed over the course of the war, the problems confronting the Continental Army eventually brought it to the breaking point. No less than four major mutinies, involving soldiers or officers, occurred between 1780-1783. This essay focuses on the reasons for the mutinies and how the participants justified their actions. It also examines responses from General Washington and other senior officers, and what effects these actions had on the army. Finally, this essay addresses the question of why so few major mutinies occurred given the miserable state of the Continental Army.

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Vorbesitzer: Heinrich Anton Cornill-d'Orville (Exlibris im Vorderdeckel);

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The magnetic polarity stratigraphy at Site 907 obtained from the shipboard pass-through magnetometer and from discrete samples is readily interpretable back to the onset of the Gilbert Chron (5.89 Ma). From this level to the base of the section at ~14 Ma, the interpretation is corroborated by silicoflagellate datums with predictable correlation to polarity chrons. The resulting magnetostratigraphic interpretation differs from those proposed in the Leg 151 (Hole 907A) and 162 (Holes 907B and 907C) Initial Reports volumes. An important hiatus in the 7-10 Ma interval at Site 907 caused sedimentation to slow or cease for ~2.7 m.y. We have revised the shipboard correlation among the three holes at Site 907, resulting in a new composite section splice and recalculation of composite depths. For Site 985, magnetostratigraphic interpretation is possible down to ~150 meters below seafloor (mbsf) (C3An/C3Ar) at ~6 Ma. There are no useful biostratigraphic datums from Site 985 to support this interpretation; however, the interpretation is supported by the correlation of Sites 985 and 907 using natural gamma data from the shipboard multisensor track. Below ~150 mbsf at Site 985, drilling-related deformation at the onset of extended core barrel drilling precluded magnetostratigraphic interpretation.

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Few high-latitude terrestrial records document the timing and nature of the Cenozoic "Greenhouse" to "Icehouse" transition. Here we exploit the bulk geochemistry of marine siliciclastic sediments from drill cores on Antarctica's continental margin to extract a unique semiquantitative temperature and precipitation record for Eocene to mid-Miocene (~54-13 Ma). Alkaline elements are strongly enriched in the detrital mineral fraction in fine-grained siliciclastic marine sediments and only occur as trace metals in the biogenic fraction. Hence, terrestrial climofunctions similar to the chemical index of alteration (CIA) can be applied to the alkaline major element geochemistry of marine sediments on continental margins in order to reconstruct changes in precipitation and temperature. We validate this approach by comparison with published paleotemperature and precipitation records derived from fossil wood, leaves, and pollen and find remarkable agreement, despite uncertainties in the calibrations of the different proxies. A long-term cooling on the order of >=8°C is observed between the Early Eocene Climatic Optimum (~54-52 Ma) and the middle Miocene (~15-13 Ma) with the onset of transient cooling episodes in the middle Eocene at ~46-45 Ma. High-latitude stratigraphic records currently exhibit insufficient temporal resolution to reconstruct continental aridity and inferred ice-sheet development during the middle to late Eocene (~45-37 Ma). However, we find an abrupt aridification of East Antarctica near the Eocene-Oligocene transition (~34 Ma), which suggests that ice coverage influenced high-latitude atmospheric circulation patterns through albedo effects from the earliest Oligocene onward.

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Multiple holes were cored at Ocean Drilling Program Leg 178 Sites 1098 and 1099 in two subbasins of the Palmer Deep in order to recover complete and continuous records of sedimentation. By correlating measured properties of cores from different holes at a site, we have established a common depth scale, referred to as the meters composite depth scale (mcd), for all cores from Site 1098. For Site 1098, distinct similarities in the magnetic susceptibility records obtained from three holes provide tight constraints on between-hole correlation. Additional constraints come from lithologic features. Specific intervals from other data sets, particularly gamma-ray attenuation bulk density, magnetic intensity, and color reflectance, contain distinctive anomalies that correlate well when placed into the preferred composite depth scale, confirming that the scale is accurate. Coring in two holes at Site 1099 provides only a few meters of overlap. None of the data sets within this limited overlap region provide convincing correlations. Thus, the preferred composite depth scale for Site 1099 is the existing depth scale in meters below seafloor (mbsf).

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We report the paleomagnetic and rock magnetic results from discrete sample analysis of sediments from Walvis Ridge, Leg 208 of the Ocean Drilling Program. In an effort to refine the shipboard magnetostratigraphy, alternating field and thermal demagnetization of discrete samples were carried out, predominantly on samples from Sites 1262 and 1267. Results are generally consistent with the shipboard pass-through cryomagnetometer data, though in some cases the discrete samples resolved ambiguities in the reversal record. Significantly, the C24r/C24n reversal boundary was identified at Sites 1262 and 1267, and most boundaries in the Paleocene and Upper Cretaceous sections are now identified to within 10-30 cm. Magnetic mineralogy results show that prior to the late Miocene, the predominant detrital magnetic component was coarse-grained magnetite and that after the late Miocene, titanomagnetite has also been present. This suggests a possible change in detrital source at that time.