scholarly journals The surface of (4) Vesta in visible light as seen by Dawn/VIR

2021 ◽  
Vol 653 ◽  
pp. A118
Author(s):  
B. Rousseau ◽  
M. C. De Sanctis ◽  
A. Raponi ◽  
M. Ciarniello ◽  
E. Ammannito ◽  
...  
Keyword(s):  
Impact Craters ◽  
The Other ◽  
Upper Crust ◽  
Entire Surface ◽  
Spectral Parameters ◽  
Band Center ◽  
Band Area ◽  
Radiance Factor ◽  
Visible Wavelengths ◽  
Peculiar Behavior

Aims. We analyzed the surface of Vesta at visible wavelengths, using the data of the Visible and InfraRed mapping spectrometer (VIR) on board the Dawn spacecraft. We mapped the variations of various spectral parameters on the entire surface of the asteroid, and also derived a map of the lithology. Methods. We took advantage of the recent corrected VIR visible data to map the radiance factor at 550 nm, three color composites, two spectral slopes, and a band area parameter relative to the 930 nm crystal field signature in pyroxene. Using the howardite-eucrite-diogenite meteorites data as a reference, we derived the lithology of Vesta using the variations of the 930 and 506 nm (spin-forbidden) band centers observed in the VIR dataset. Results. Our spectral parameters highlight a significant spectral diversity at the surface of Vesta. This diversity is mainly evidenced by impact craters and illustrates the heterogeneous subsurface and upper crust of Vesta. Impact craters also participate directly in this spectral diversity by bringing dark exogenous material to an almost entire hemisphere. Our derived lithology agrees with previous results obtained using a combination of infrared and visible data. We therefore demonstrate that it is possible to obtain crucial mineralogical information from visible wavelengths alone. In addition to the 506 nm band, we identified the 550 nm spin-forbidden one. As reported by a laboratory study for synthetic pyroxenes, we also do not observe any shift of the band center of this feature across the surface of Vesta, and thus across different mineralogies, preventing use of the 550 nm spin-forbidden band for the lithology derivation. Finally, the largest previously identified olivine rich-spot shows a peculiar behavior in two color composites but not in the other spectral parameters.

scholarly journals The surface of (1) Ceres in visible light as seen by Dawn/VIR

2020 ◽  
Vol 642 ◽  
pp. A74 ◽  
Author(s):  
B. Rousseau ◽  
M. C. De Sanctis ◽  
A. Raponi ◽  
M. Ciarniello ◽  
E. Ammannito ◽  
...  
Keyword(s):  
Visible Light ◽  
Impact Crater ◽  
Steep Slope ◽  
Visible Range ◽  
Spectral Slope ◽  
Spectral Parameters ◽  
Radiance Factor ◽  
Visible Wavelengths ◽  
Carbonate Species ◽  
Color Composite

Aims. We study the surface of Ceres at visible wavelengths, as observed by the Visible and InfraRed mapping spectrometer (VIR) onboard the Dawn spacecraft, and analyze the variations of various spectral parameters across the whole surface. We also focus on several noteworthy areas of the surface of this dwarf planet. Methods. We made use of the newly corrected VIR visible data to build global maps of a calibrated radiance factor at 550 nm, with two color composites and three spectral slopes between 400 and 950 nm. We have made these maps available for the community via the Aladin Desktop software. Results. Ceres’ surface shows diverse spectral behaviors in the visible range. The color composite and the spectral slope between 480 and 800 nm highlight fresh impact craters and young geologic formations of endogenous origin, which appear bluer than the rest of the surface. The steep slope before 465 nm displays very distinct variations and may be a proxy for the absorptions caused by the O2− → Fe3+ or the 2Fe3+ → Fe2+ + Fe4+ charge transfers, if the latter are found to be responsible for the drop in this spectral range. We notice several similarities between the spectral slopes and the abundance of phyllosilicates detected in the infrared by the VIR, whereas no correlation can be clearly established with carbonate species. The region of the Dantu impact crater presents a peculiar spectral behavior – especially through the color and the spectral slope before 465 nm – suggesting a change in composition or in the surface physical properties that is not observed elsewhere on Ceres.

Building Materials and Techniques

1997 ◽  
Author(s):  
Roger Ling ◽  
Paul Arthur ◽  
Georgia Clarke ◽  
Estelle Lazer ◽  
Lesley A. Ling ◽  
...  
Keyword(s):  
Building Materials ◽  
The Other ◽  
Upper Crust ◽  
Calcareous Tufa ◽  
Volcanic Ashes ◽  
Wear And Tear ◽  
Modern House ◽  
Working Out ◽  
Yellowish White

Much of the ensuing discussion will focus on the working-out of structural sequences, first within individual houses or parts of houses, then within the insula as a whole. As a preface to this discussion, it is necessary to give a description of the building materials and techniques found in the insula. Brief surveys of Pompeian building techniques have appeared in various publications. Still one of the most serviceable accounts is that of R. C. Carrington in his article ‘Notes on the building materials of Pompeii” published in 1933, and most of the forms of construction found in I10 are discussed therein. First, the materials. The commonest is the socalled ‘Sarno stone’ (often inaccurately called limestone’), a yellowish white calcareous tufa which is very rough and porous, being riddled with the imprints of shells and vegetable matter; it is used both in large blocks to form quoins and the like and in smaller rubble for facing and infilling of all types. Next most common is a hard grey (trachytic) lava which is stronger and more water resistant than Sarno stone but which, because it is less easy to cut into regular shapes, is generally employed in the form of small rubble. An exception to this rule is its use for door thresholds, where its hardness is well suited to withstanding wear and tear. Rather less common in our insula is the red or purple vesicular lava known as cruma (English “scoria”), derived from the frothy upper crust of consolidated lava streams; it is occasionally cut into small blocks but more normally occurs as a sporadic material in rubble wall-facings where Sarno stone and grey lava predominate. The other main lithic materials found in the insula are varieties of tufo (tuff), formed by the consolidation of volcanic ashes. The brown or grey tuff from Nuceria (modern Nocera) is a hard and close-grained material containing darker brown or blackish specks. It can be easily cut to shape when freshly exposed in the quarry but hardens later on contact with the air, so is ideally suited for producing ashlar blocks, small tufelli (blocks of similar size to modern house bricks) and the pyramidal pieces used in reticulate work (opus reticulaium: see below), not to mention carved detail such as column and pilaster capitals.

scholarly journals Non-Destructive Monitoring of P. fluorescens and S. epidermidis Biofilm under Different Media by Fourier Transform Infrared Spectroscopy and Other Corroborative Techniques

Coatings ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 930
Author(s):  
Marco Consumi ◽  
Kamila Jankowska ◽  
Gemma Leone ◽  
Claudio Rossi ◽  
Alessio Pardini ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Staphylococcus Epidermidis ◽  
Biofilm Formation ◽  
Early Stage ◽  
Deionized Water ◽  
The Other ◽  
Ftir Technique ◽  
Low Sensitivity ◽  
Non Destructive ◽  
Peculiar Behavior

In the present study, the early stage of bacteria biofilm formation has been studied as a function of different nutrients. Infrared spectra of Pseudomonas fluorescens (PF) and Staphylococcus epidermidis (SE), on germanium ATR crystal, were collected under deionized water H2O, phosphate buffered solution (PBS) and PBS with glucose (PBS-G). In H2O, protein bands of PF increased while, no difference in PBS and PBS-G were observed until 135 min. SE strain showed a low sensitivity to PBS composition starting to expose proteins on surfaces after 120 min. SE shows a low polysaccharides increase in H2O while, in bare and enriched PBS their intensity increases after 120 and 75 min. in PBS and PBS-G respectively. PF exhibits a peculiar behavior in H2O where the saccharide bands increased strongly after 100 min, while under all the other conditions, the intensity of polysaccharide bands increased up to the plateau probably because the layer of the biofilm exceeded the penetration capability of FTIR technique. All data suggest that, under lack of nutrients, both the bacteria tend to firmly anchor themselves to the support using proteins.

The structure and formation of metacercarial cysts in the trematode family Microphallidae Travassos 1920

1997 ◽  
Vol 71 (1) ◽  
pp. 13-20 ◽  
Author(s):  
K.V. Galaktionov ◽  
I.I. Malkova ◽  
S.W.B. Irwin ◽  
D.H. Saville ◽  
J.G. Maguire
Keyword(s):  
Outer Layer ◽  
Post Infection ◽  
Secretory Granules ◽  
Heterogeneous Material ◽  
The Other ◽  
Ventral Region ◽  
Entire Surface ◽  
Excretory Bladder

AbstractThis study deals with the formation of the metacercarial cysts of four microphallid trematodes, Maritrema subdolum, M. arenaria, Levinseniella brachysoma and Microphallus claviformis. The first observable cyst was present around Maritrema arenaria 18 h p.i. (post-infection). The other species had not developed a cyst by day 8 p.i. but their cysts were apparent by day 16 p.i. These were bi-layered and that of M. subdolum was thicker than those of L. brachysoma and Microphallus claviformis of the same age. The structure of older cysts varied substantially between the four species. Microphallus claviformis and Maritrema subdolum cysts were fully formed at 30 days p.i. Like those of M. arenaria they were bi-layered, the outer layer (up to 3 μm thick) being electron-dense and the inner one (up to 7 μm thick) being less electron-dense. The cysts of fully formed L. brachysoma metacercariae were much more complex, composed of four layers, one of which was divisible into three sub-layers. It was concluded that the outer cyst layer was the product of secretory granules which were previously identified in cercarial tegument. The inner, thicker layer was derived from several sources. These included small tegument vesicles produced over the entire surface of the metacercariae, larger fragments of tegument released from the anterio-ventral region and material liberated from the metacercarial excretory bladder. This heterogeneous material accumulated in the cyst lumen for some time before becoming polymerized to form the thick inner layer or layers of the metacercarial cysts.

scholarly journals The chameleon on the branches: spectral state transition and dips in NGC 247 ULX-1

2021 ◽  
Author(s):  
A D’Aí ◽  
C Pinto ◽  
M Del Santo ◽  
F Pintore ◽  
R Soria ◽  
...  
Keyword(s):  
High Resolution ◽  
State Transition ◽  
Black Body ◽  
The Other ◽  
Spectral Parameters ◽  
Data Set ◽  
X Ray ◽  
Monitoring Campaign ◽  
Normal Branch ◽  
Spectral State

Abstract Soft Ultra-Luminous X-ray (ULXs) sources are a sub-class of the ULXs that can switch from a supersoft spectral state, where most of the luminosity is emitted below 1 keV, to a soft spectral state with significant emission above 1 keV. In a few systems, dips have been observed. The mechanism behind this state transition and the dips nature are still debated. To investigate these issues, we obtained a long XMM-Newton monitoring campaign of a member of this class, NGC 247 ULX-1. We computed the hardness-intensity diagram for the whole data-set and identified two different branches: the normal branch and the dipping branch, which we study with four and three hardness-intensity resolved spectra, respectively. All seven spectra are well described by two thermal components: a colder (kTbb ∼ 0.1-0.2 keV) black-body, interpreted as emission from the photo-sphere of a radiatively-driven wind, and a hotter (kTdisk ∼ 0.6 keV) multi-colour disk black-body, likely due to reprocessing of radiation emitted from the innermost regions. In addition, a complex pattern of emission and absorption lines has been taken into account based on previous high-resolution spectroscopic results. We studied the evolution of spectral parameters and flux of the two thermal components along the two branches and discuss two scenarios possibly connecting the state transition and the dipping phenomenon. One is based on geometrical occultation of the emitting regions, the other invokes the onset of a propeller effect.

Precipitation of high-quality multilayer-graphene using Al2O3 barrier and Au cap layers

2015 ◽  
Vol 1786 ◽  
pp. 13-18 ◽  
Author(s):  
Jumpei Yamada ◽  
Manabu Suzuki ◽  
Yuki Ueda ◽  
Takahiro Maruyama ◽  
Shigeya Naritsuka
Keyword(s):  
Low Temperature ◽  
Barrier Layer ◽  
Intensity Ratio ◽  
The Other ◽  
Multilayer Graphene ◽  
High Quality ◽  
Entire Surface ◽  
Capping Layer ◽  
Layer Graphene ◽  
Surface Migration

ABSTRACTThe mechanism for the precipitation of multilayer graphene was investigated with respect to the use of an Al2O3 barrier layer and Au capping layer. The Al2O3 barrier layer suppresses the dissolution of carbon into the catalyst, especially at low temperature, and assists a decrease in the density of graphene nuclei. On the other hand, the Au capping layer is beneficial to weaken the strong binding between the catalyst and the graphene carbon atoms, and enhances the surface migration of precipitated carbon adatoms. A combination of the Al2O3 barrier layer and Au capping layer is useful for the synthesis of high-quality graphene with large grains. On a sample with both layers annealed for 60 min, the area of 5-layer graphene islands is as large as 10 μm, and covers 60% of the entire surface. The Raman D/G band intensity ratio of 0.024 indicates the precipitated graphene is high quality.

Compositional characterization of V-type candidate asteroids identified using the MOVIS catalogue

2019 ◽  
Vol 488 (3) ◽  
pp. 3866-3875 ◽  
Author(s):  
H Medeiros ◽  
J de León ◽  
D Lazzaro ◽  
M Popescu ◽  
V Lorenzi ◽  
...  
Keyword(s):  
Infrared Spectra ◽  
Near Infrared ◽  
Spectral Parameters ◽  
Optical Telescope ◽  
Isaac Newton ◽  
Infrared Telescope ◽  
Band Area ◽  
La Palma ◽  
Near Infrared Spectra ◽  
The Right

ABSTRACT The main objective of this work is to compositionally analyse the visible to near-infrared spectra of a total of six V-type candidates identified using the MOVIS (Y-J) versus (J-Ks) colour–colour plot and located outside the Vesta collisional family. We obtained visible and near-infrared spectra of these asteroids using the 2.54m Isaac Newton Telescope, the 2.5m Nordic Optical Telescope, and the 3.58m Telescopio Nazionale Galileo, all located at the El Roque de Los Muchachos Observatory (La Palma, Spain), as well as the 3.0m NASA Infrared Telescope Facility, located at the Mauna Kea Observatory in Hawaii. We computed several diagnostic spectral parameters (slopes, band centres, band depths, band area ratio, or BAR) and compared them to the ones known for HED meteorites and (4) Vesta. The taxonomic classification confirmed five out of the six candidates as V-types, leading to an identification success rate about 83 per cent. In general, the spectral parameters obtained for the five V-types are in good agreement with those of HED meteorites and (4) Vesta. The exception is asteroid (2452) Lyot, a V-type in the outer belt, located very close to (1459) Magnya, but showing distinct [Wo] and [Fs] molar contents both from Magnya and Vesta, pointing toward a diogenitic compostion. We also studied the dependency of the BAR parameter on the way it is computed (removing or not the continuum), the spectral slope, and the last point used to delimit the right wing of the absorption band at 2 μm.

On the Mechanics of Faulting

1942 ◽  
Vol 79 (5) ◽  
pp. 291-295 ◽  
Author(s):  
Harold Jeffreys
Keyword(s):  
Outer Surface ◽  
Large Earthquake ◽  
The Other ◽  
Upper Crust ◽  
Total Displacement ◽  
Mechanics Of Faulting ◽  
Seismological Data ◽  
Abundant Evidence ◽  
Long Time ◽  
Geological Observation

1. Geological observation provides abundant evidence of fractures in the upper crust, the relative displacements of the sides of a fracture being anything from a few centimetres to thousands of metres. It is generally believed that earthquakes are produced in these displacements, but little attention seems to have been given to the quantitative relations involved. The geologist sees the record of the total displacement, but has no direct information about how long it took to occur, or whether it took place all at once or by several stages. Except in cases where an earthquake has been associated with fracture of the outer surface, and we can say how much displacement occurred up to the time of inspection, he has no means of knowing whether it took seconds, hours, years, or geological periods to form. Even in these rather rare cases the displacement is not more than a few metres, and extrapolation to the larger known faults is impossible. Seismology on the other hand is well adapted to the study of sudden shifts, but the instruments do not record large movements spread over a long time; thus the geological and seismological data are largely complementary. It is known also that a large earthquake is often followed by a swarm of small ones, called aftershocks, apparently from the same focus and continuing for, possibly, several months; there may be a thousand in a single series. The geological displacement observed long afterwards will include those due to all the aftershocks, supposing, as is generally done, that they all are due to shifts on the same fault.

A new species of Suphisellus Crotch, 1873 (Coleoptera: Noteridae) from “Los Llanos”, Venezuela

Zootaxa ◽  
2012 ◽  
Vol 3298 (1) ◽  
pp. 62 ◽  
Author(s):  
MAURICIO GARCÍA ◽  
CESAR JOÃO BENETTI ◽  
JESÚS CAMACHO
Keyword(s):  
New Species ◽  
Male Genitalia ◽  
Light Trap ◽  
Systematic Position ◽  
The Other ◽  
Medial Part ◽  
Entire Surface ◽  
Number Of Species ◽  
A New Species

Suphisellus shorti sp. n. is described from “Los Llanos”, Venezuela, which brings to six the number of species includedin the Noteridae genus Suphisellus Crotch, 1873 recorded in this country. Specimens were collected in The Plains regionin Venezuela (Apure and Guarico states) using either a light trap or a net. Description and illustration of the new speciesare provided along with a discussion of its systematic position. The new species can be distinguished from the other spe-cies of the genus by the following main characters: crease at posterolateral angle of pronotum weakly marked; numerous setae covering entire surface of prosternal process and medial part of prosternum; shape of male genitalia.

scholarly journals STUDIES ON THE ETIOLOGY OF SPONTANEOUS CONJUNCTIVAL FOLLICULOSIS OF RABBITS

1934 ◽  
Vol 60 (1) ◽  
pp. 107-118 ◽  
Author(s):  
Peter K. Olitsky ◽  
Jerome T. Syverton ◽  
Joseph R. Tyler
Keyword(s):  
Inclusion Bodies ◽  
The Other ◽  
Low Grade ◽  
Type I ◽  
Type Ii ◽  
Entire Surface ◽  
Inflammatory Reactions ◽  
Natural Processes ◽  
Pathogenic Action ◽  
Experimental Disease

Spontaneous conjunctival folliculosis is widespread among various species of rabbits. It exists in two forms: Type I, in which the lesions are localized and the disease is relatively inactive, and Type II, in which the follicles are closely distributed over the entire surface of the conjunctivae and the affection is more active and characterized by extensive inflammatory reactions. One type can be converted into the other either by experimental methods or by natural processes. The disease can be transmitted from rabbit to rabbit by means of subconjunctival inoculation of suspensions of the affected tissues or by instillation of such material into the conjunctival sac, or even by mere contact of folliculosis animals with rabbits having smooth conjunctivae. It is plain that the disease is an infection. The causal agent of the infection is not filtrable through Seitz discs that retain Serratia marcescens nor through Berkefeld V candles that permit the passage of this organism. Furthermore, the lesions of the spontaneous or of the experimental disease do not exhibit the cytotropic effects or the inclusion bodies suggestive of the action of an ultramicroscopic virus. They are characterized, on the other hand, by a persistent and progressive chronicity and show certain resemblances to the granulomata. The evidence suggests that the spontaneous conjunctival folliculosis of rabbits is due to a microorganism—one having a low grade pathogenic action. In a paper shortly to be published, a bacterium capable of reproducing folliculosis in normal rabbits will be described.

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