Switching Equivalence in Symmetric n-Sigraphs-V

Introducing a new notion S-antipodal symmetric n-sigraph of a symmetric n-sigraph and its properties are obtained. Also giving the relation between antipodal symmetric n-sigraphs and S-antipodal symmetric n-sigraphs. Further, discussing structural characterization of S-antipodal symmetric n-sigraphs

Mapping the mineralogical composition of the Pinaria region (Av-11) of Vesta

We present the mineralogical map of a quadrant of the southern hemisphere of Vesta spanning 0-90 degrees longitude, and -21 to -66 degrees latitude; a region named Pinaria. The region, named after the Roman vestal virgin (c. 600 B.C.), includes an approximately 37km diameter crater, also named Pinaria. Several additional large craters are in this region as is the western most region of the rim of Rhea Silvia, named Matronalia Rupes. Mineralogical maps are based on data acquired by the Visible and Infrared Mapping Spectrometer (VIR-MS) and the Framing Camera (FC) on the Dawn spacecraft that has been orbiting Vesta since July 2011. VIR-MS is sensitive to wavelengths from 0.25um to 5.1um with a spatial resolution that depends upon the mission phase: nominally from 2.5 up to 0.8 km/pixel during the approach, 0.8 km/pixel during survey, 0.2 km/pixel during the high altitude orbit (HAMO) and about 0.05 km/pixel during the low altitude orbit (LAMO). This spatial resolution does not include the effects of the spacecraft's nor Vesta's motion. FC data from Survey orbit with a spatial resolution of about 250 m/pixel have been mapped using filter band parameters selected to enhance the anticipated mineralogy of Vesta. Global color maps of Vesta's surface using these color differences and ratios are generated. VIR data show that Vesta's surface is dominated by pyroxenes, with no evidence for the presence of other minerals observed at the scale of the survey measurements. The spectral parameters of the two major pyroxene absorption bands including band centers, depths and band areas and their variation within the Pinaria region, suggest mineralogical variation representing different compositional and/or textural terrains. Matronalia Rupes has band parameters suggesting different composition or grain size possibly resulting from down slope motion of regolith revealing different material beneath. The authors gratefully acknowledge the support of the Dawn Instrument, Operations, and Science Teams. This work is supported by an Italian Space Agency (ASI) grant, the DLR, MPI and by NASA through the Dawn project and the Dawn at Vesta Participating Scientist grant

Statefinder Parameters for Different Dark Energy Models with Variable G Correction in Kaluza-Klein Cosmology

In this work, we have calculated the deceleration parameter, statefinder parameters and EoS parameters for different dark energy models with variable $G$ correction in homogeneous, isotropic and non-flat universe for Kaluza-Klein Cosmology. The statefinder parameters have been obtained in terms of some observable parameters like dimensionless density parameter, EoS parameter and Hubble parameter for holographic dark energy, new agegraphic dark energy and generalized Chaplygin gas models.Comment: 9 pages, no figure, accepted for publication in IJTP. arXiv admin note: text overlap with arXiv:1104.2366 by other author

A Mechanistic Paradigm for Broad-Spectrum Antivirals that Target Virus-Cell Fusion

10.1371/journal.ppat.1003297PLoS Pathogens94

Survivability of copper projectiles during hypervelocity impacts in porous ice: A laboratory investigation of the survivability of projectiles impacting comets or other bodies

AbstractDuring hypervelocity impact (>a few kms−1) the resulting cratering and/or disruption of the target body often outweighs interest on the outcome of the projectile material, with the majority of projectiles assumed to be vaporised. However, on Earth, fragments, often metallic, have been recovered from impact sites, meaning that metallic projectile fragments may survive a hypervelocity impact and still exist within the wall, floor and/or ejecta of the impact crater post-impact. The discovery of the remnant impactor composition within the craters of asteroids, planets and comets could provide further information regarding the impact history of a body. Accordingly, we study in the laboratory the survivability of 1 and 2mm diameter copper projectiles fired onto ice at speeds between 1.00 and 7.05kms−1. The projectile was recovered intact at speeds up to 1.50kms−1, with no ductile deformation, but some surface pitting was observed. At 2.39kms−1, the projectile showed increasing ductile deformation and broke into two parts. Above velocities of 2.60kms−1 increasing numbers of projectile fragments were identified post impact, with the mean size of the fragments decreasing with increasing impact velocity. The decrease in size also corresponds with an increase in the number of projectile fragments recovered, as with increasing shock pressure the projectile material is more intensely disrupted, producing smaller and more numerous fragments. The damage to the projectile is divided into four classes with increasing speed and shock pressure: (1) minimal damage, (2) ductile deformation, start of break up, (3) increasing fragmentation, and (4) complete fragmentation. The implications of such behaviour is considered for specific examples of impacts of metallic impactors onto Solar System bodies, including LCROSS impacting the Moon, iron meteorites onto Mars and NASA’s “Deep Impact” mission where a spacecraft impacted a comet

The Geology of the Marcia Quadrangle of Asteroid Vesta: Assessing the Effects of Large, Young Craters

We used Dawn spacecraft data to identify and delineate geological units and landforms in the Marcia quadrangle of Vesta as a means to assess the role of the large, relatively young impact craters Marcia (approximately 63 kilometers diameter) and Calpurnia (approximately 53 kilometers diameter) and their surrounding ejecta field on the local geology. We also investigated a local topographic high with a dark-rayed crater named Aricia Tholus, and the impact crater Octavia that is surrounded by a distinctive diffuse mantle. Crater counts and stratigraphic relations suggest that Marcia is the youngest large crater on Vesta, in which a putative impact melt on the crater floor ranges in age between approximately 40 and 60 million years (depending upon choice of chronology system), and Marcia's ejecta blanket ranges in age between approximately 120 and 390 million years (depending upon choice of chronology system). We interpret the geologic units in and around Marcia crater to mark a major Vestan time-stratigraphic event, and that the Marcia Formation is one of the geologically youngest formations on Vesta. Marcia crater reveals pristine bright and dark material in its walls and smooth and pitted terrains on its floor. The smooth unit we interpret as evidence of flow of impact melts and (for the pitted terrain) release of volatiles during or after the impact process. The distinctive dark ejecta surrounding craters Marcia and Calpurnia is enriched in OH- or H-bearing phases and has a variable morphology, suggestive of a complex mixture of impact ejecta and impact melts including dark materials possibly derived from carbonaceous chondrite-rich material. Aricia Tholus, which was originally interpreted as a putative Vestan volcanic edifice based on lower resolution observations, appears to be a fragment of an ancient impact basin rim topped by a dark-rayed impact crater. Octavia crater has a cratering model formation age of approximately 280-990 million years based on counts of its ejecta field (depending upon choice of chronology system), and its ejecta field is the second oldest unit in this quadrangle. The relatively young craters and their related ejecta materials in this quadrangle are in stark contrast to the surrounding heavily cratered units that are related to the billion years old or older Rheasilvia and Veneneia impact basins and Vesta's ancient crust preserved on Vestalia Terra

A Model for the Development of the Rhizobial and Arbuscular Mycorrhizal Symbioses in Legumes and Its Use to Understand the Roles of Ethylene in the Establishment of these two Symbioses

We propose a model depicting the development of nodulation and arbuscular mycorrhizae. Both processes are dissected into many steps, using Pisum sativum L. nodulation mutants as a guideline. For nodulation, we distinguish two main developmental programs, one epidermal and one cortical. Whereas Nod factors alone affect the cortical program, bacteria are required to trigger the epidermal events. We propose that the two programs of the rhizobial symbiosis evolved separately and that, over time, they came to function together. The distinction between these two programs does not exist for arbuscular mycorrhizae development despite events occurring in both root tissues. Mutations that affect both symbioses are restricted to the epidermal program. We propose here sites of action and potential roles for ethylene during the formation of the two symbioses with a specific hypothesis for nodule organogenesis. Assuming the epidermis does not make ethylene, the microsymbionts probably first encounter a regulatory level of ethylene at the epidermis–outermost cortical cell layer interface. Depending on the hormone concentrations there, infection will either progress or be blocked. In the former case, ethylene affects the cortex cytoskeleton, allowing reorganization that facilitates infection; in the latter case, ethylene acts on several enzymes that interfere with infection thread growth, causing it to abort. Throughout this review, the difficulty of generalizing the roles of ethylene is emphasized and numerous examples are given to demonstrate the diversity that exists in plants