1,131 research outputs found
The stratigraphy and structure of the syncline of stainmore
The stainmore area is a typographical and geological depression lying between the two upstanding block areas of the Northern Pennines. The succession includes bede of Yoredale facies of the middle and upper Limestone groups, overlain by “Millstone Grit”, the total time range extending from late P(_2) age, probably to late E(_2). Detailed mapping of marine horizons has enabled the establishment of correlations between the successions of the Alston block to the north and tho Askrigg block to the south, They show that marine conditions were more persistant to the south and east of the stainmore area. Millstone grit facies entorent a lower horizon in the east and west of the stainmore area than it does in tho centre. Tho grite on the flanko correspond to the tenhill grite of N. W. Swaledale and are considered to pass laterally into the coaleleugh transgression bods in the centre. This is demonstrated by equating the upper felltop Limestone of Alston with the Heane Beck Limestone of upper Swaledale. An upper horizon of grit facies is subjacent to Botany Limestone and is considered to be the equivalent of the first Millstone crit of Durham and the water crag Grit of Upper Swaledale, the Botany Limestone corresponding to the shunner pell Limestone. The structure consists of an asymmetrical syncline, pitching gently to the east, with two small elongated domes to the south. The fault pattern on the east is similar to that of Alston block; on the west a semi-radical pattern is apparent. Joint directions are varied. The area has been affected by both the stainmore and Teesdale glaciers, the former being dominant only at first, and showing evidence of a minor readvance and second retreat
Sub-wavelength surface IR imaging of soft-condensed matter
Outlined here is a technique for sub-wavelength infrared surface imaging
performed using a phase matched optical parametric oscillator laser and an
atomic force microscope as the detection mechanism. The technique uses a novel
surface excitation illumination approach to perform simultaneously chemical
mapping and AFM topography imaging with an image resolution of 200 nm. This
method was demonstrated by imaging polystyrene micro-structures
Associahedra via spines
An associahedron is a polytope whose vertices correspond to triangulations of
a convex polygon and whose edges correspond to flips between them. Using
labeled polygons, C. Hohlweg and C. Lange constructed various realizations of
the associahedron with relevant properties related to the symmetric group and
the classical permutahedron. We introduce the spine of a triangulation as its
dual tree together with a labeling and an orientation. This notion extends the
classical understanding of the associahedron via binary trees, introduces a new
perspective on C. Hohlweg and C. Lange's construction closer to J.-L. Loday's
original approach, and sheds light upon the combinatorial and geometric
properties of the resulting realizations of the associahedron. It also leads to
noteworthy proofs which shorten and simplify previous approaches.Comment: 27 pages, 11 figures. Version 5: minor correction
Recent Advances in Nuclear Powered Electric Propulsion for Space Exploration
Nuclear and radioisotope powered electric thrusters are being developed as primary in-space propulsion systems for potential future robotic and piloted space missions. Possible applications for high power nuclear electric propulsion include orbit raising and maneuvering of large space platforms, lunar and Mars cargo transport, asteroid rendezvous and sample return, and robotic and piloted planetary missions, while lower power radioisotope electric propulsion could significantly enhance or enable some future robotic deep space science missions. This paper provides an overview of recent U.S. high power electric thruster research programs, describing the operating principles, challenges, and status of each technology. Mission analysis is presented that compares the benefits and performance of each thruster type for high priority NASA missions. The status of space nuclear power systems for high power electric propulsion is presented. The paper concludes with a discussion of power and thruster development strategies for future radioisotope electric propulsion systems
Identification of electrofacies on the basis of well logging to determine sedimentation environment of horizon JK[2] in Em-Egovskoe field (Western Siberia)
Well logging results are one of the ways to study the buried terrigenous rocks genesis. To ensure the most objective characterization of the rock and identification of electrofacies it is necessary to use a complex geological and geophysical survey. The comprehensive investigations of environmental conditions based on well logging have been performed for the horizon JK[2] of Tumenskoe formation in Em-Egovskoe area, Krasnoleninskoe field (Western Siberia). The defined electrofacies were compared with the results of earlier conducted granulometric and mineralogical analyses. The totality of research provided for a conclusion that the investigated sediments of horizon JK2 had been formed within the destructive tidal delta. Thus, objective facies prediction can only be ensured by analyzing core and well logging data comprehensively
Syn‐rift sediment gravity flow deposition on a Late Jurassic fault‐terraced slope, northern North Sea
Structurally controlled bathymetry in rifts has a significant influence on sediment routing pathways and depositional architecture of sediment gravity flow deposits. In contrast to rift segments characterized by crustal-scale half-grabens, the tectono-stratigraphic evolution of deep-water rift domains characterised by distributed faulting on narrow fault terraces has received little attention. We use 3D broadband seismic data, calibrated by boreholes, from the Lomre and Uer terraces in the northern North Sea rift to investigate Late Jurassic syn-rift sediment gravity flow systems on fault-terraced slopes. The sediment gravity flow fairways were sourced from hinterland drainages via basin margin deltaic systems on the Horda Platform to the southeast. The deep-water sedimentary systems evolve from initial, widespread submarine channelized lobe complexes, through submarine channels, to incised submarine canyons. This progressive confinement of the sediment gravity flow system was concomitant with progressive localization of strain onto the main terrace-bounding faults. Although the normal fault network on the terraces has local impact on deep-water sediment transport and the architecture of gravity flow deposits, it is the regional basin margin to rift axis gradient that dominantly controls deep-water sediment routing. Furthermore, the gravity flow deposits on the Lomre and Uer terraces were predominantly sourced by rift margin deltaic systems, not from erosion of local uplifted footwall crests, emphasising the significance of hinterland catchments in the development of volumetrically significant deep-water syn-rift depositional systems
Subword complexes, cluster complexes, and generalized multi-associahedra
In this paper, we use subword complexes to provide a uniform approach to
finite type cluster complexes and multi-associahedra. We introduce, for any
finite Coxeter group and any nonnegative integer k, a spherical subword complex
called multi-cluster complex. For k=1, we show that this subword complex is
isomorphic to the cluster complex of the given type. We show that multi-cluster
complexes of types A and B coincide with known simplicial complexes, namely
with the simplicial complexes of multi-triangulations and centrally symmetric
multi-triangulations respectively. Furthermore, we show that the multi-cluster
complex is universal in the sense that every spherical subword complex can be
realized as a link of a face of the multi-cluster complex.Comment: 26 pages, 3 Tables, 2 Figures; final versio
The Role of Neutrophils during Mild and Severe Influenza Virus Infections of Mice
Neutrophils have been implicated in both protective and pathological responses following influenza virus infections. We have used mAb 1A8 (anti-Ly6G) to specifically deplete LyG6high neutrophils and induce neutropenia in mice infected with virus strains known to differ in virulence. Mice were also treated with mAb RB6-8C5 (anti-Ly6C/G or anti-Gr-1), a mAb widely used to investigate the role of neutrophils in mice that has been shown to bind and deplete additional leukocyte subsets. Using mAb 1A8, we confirm the beneficial role of neutrophils in mice infected with virus strains of intermediate (HKx31; H3N2) or high (PR8; H1N1) virulence whereas treatment of mice infected with an avirulent strain (BJx109; H3N2) did not affect disease or virus replication. Treatment of BJx109-infected mice with mAb RB6-8C5 was, however, associated with significant weight loss and enhanced virus replication indicating that other Gr-1+ cells, not neutrophils, limit disease severity during mild influenza infections
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