scholarly journals Light Echoes of Transients and Variables in the Local Universe

2012 ◽  
Vol 29 (4) ◽  
pp. 466-481 ◽  
Author(s):  
A. Rest ◽  
B. Sinnott ◽  
D. L. Welch
Keyword(s):  
Interstellar Dust ◽  
Three Dimensional ◽  
Large Magellanic Cloud ◽  
Multiple Perspectives ◽  
Local Universe ◽  
New Developments ◽  
Light Echoes ◽  
Dimensional Distribution ◽  
History Of ◽  
The Many

AbstractAstronomical light echoes, the time-dependent light scattered by dust in the vicinity of varying objects, have been recognized for over a century. Initially, their utility was thought to be confined to mapping out the three-dimensional distribution of interstellar dust. Recently, the discovery of spectroscopically useful light echoes around centuries-old supernovae in the Milky Way and the Large Magellanic Cloud has opened up new scientific opportunities to exploit light echoes.In this review, we describe the history of light echoes in the local Universe and cover the many new developments in both the observation of light echoes and the interpretation of the light scattered from them. Among other benefits, we highlight our new ability to classify outbursting objects spectroscopically, view them from multiple perspectives, obtain a spectroscopic time series of the outburst, and establish accurate distances to the source event. We also describe the broader range of variable objects with properties that may be better understood from light-echo observations. Finally, we discuss the prospects of new light-echo techniques not yet realized in practice.

AAT Observations of the Interstellar Medium towards SN 1987A

1988 ◽  
Vol 7 (4) ◽  
pp. 527-534 ◽  
Author(s):  
M. Pettini
Keyword(s):  
Signal To Noise Ratio ◽  
Three Dimensional ◽  
Large Magellanic Cloud ◽  
High Spectral Resolution ◽  
High Signal ◽  
Interstellar Matter ◽  
Interstellar Clouds ◽  
Sn 1987A ◽  
Light Echoes ◽  
Dimensional Distribution

AbstractThe exceptional brightness of SN 1987A has provided a unique opportunity to probe intervening gas clouds in the disk and halo of our Galaxy and in the Large Magellanic Cloud, as well as intergalactic matter between the two. At the AAO we have exploited this opportunity in two ways: in searches for very weak interstellar features requiring exceptionally high signal-to-noise ratio spectra, and in recording known interstellar lines with unprecedentedly high spectral resolution. We are also monitoring photographically the evolution of the light-echoes to map the three-dimensional distribution of interstellar matter near the supernova. Surprisingly high column densities of million-degree gas have been found in the LMC through the first detection of [Fe X] in absorption. The hot gas may fill the interior of a ‘superbubble’, created by the combined effects of previous supernovae in this active region of star-formation; this cavity may be related to the shells of interstellar matter giving rise to the light-echoes. The ultra-high resolution observations, which required the rapid construction of a dedicated new spectrograph, were successful in resolving the hyperfine structure of the sodium D lines in several interstellar clouds. This implies that the clouds are at temperatures of at most 170 K and have internal turbulent velocities of no more than 0.3 km s−1, even though some are moving with high velocities relative to the Sun.

scholarly journals Three-dimensional molar enamel distribution and thickness in Australopithecus and Paranthropus

2008 ◽  
Vol 4 (4) ◽  
pp. 406-410 ◽  
Author(s):  
A.J Olejniczak ◽  
T.M Smith ◽  
M.M Skinner ◽  
F.E Grine ◽  
R.N.M Feeney ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Two Dimensional ◽  
Cross Sectional ◽  
Enamel Thickness ◽  
Australopithecus Africanus ◽  
Interspecific Differences ◽  
Dimensional Measurements ◽  
Dimensional Distribution ◽  
History Of ◽  
Thickness Measurements

Thick molar enamel is among the few diagnostic characters of hominins which are measurable in fossil specimens. Despite a long history of study and characterization of Paranthropus molars as relatively ‘hyper-thick’, only a few tooth fragments and controlled planes of section (designed to be proxies of whole-crown thickness) have been measured. Here, we measure molar enamel thickness in Australopithecus africanus and Paranthropus robustus using accurate microtomographic methods, recording the whole-crown distribution of enamel. Both taxa have relatively thick enamel, but are thinner than previously characterized based on two-dimensional measurements. Three-dimensional measurements show that P. robustus enamel is not hyper-thick, and A. africanus enamel is relatively thinner than that of recent humans. Interspecific differences in the whole-crown distribution of enamel thickness influence cross-sectional measurements such that enamel thickness is exaggerated in two-dimensional sections of A. africanus and P. robustus molars. As such, two-dimensional enamel thickness measurements in australopiths are not reliable proxies for the three-dimensional data they are meant to represent. The three-dimensional distribution of enamel thickness shows different patterns among species, and is more useful for the interpretation of functional adaptations than single summary measures of enamel thickness.

scholarly journals Three-dimensional Distribution of the Interstellar Dust in the Milky Way

2021 ◽  
Vol 906 (1) ◽  
pp. 47
Author(s):  
H.-L. Guo ◽  
B.-Q. Chen ◽  
H.-B. Yuan ◽  
Y. Huang ◽  
D.-Z Liu ◽  
...  
Keyword(s):  
Interstellar Dust ◽  
Milky Way ◽  
Three Dimensional ◽  
Dimensional Distribution

scholarly journals Monitoring microbial communities using light sheet fluorescence microscopy

2017 ◽  
Author(s):  
Raghuveer Parthasarathy
Keyword(s):  
Fluorescence Microscopy ◽  
Microbial Communities ◽  
Three Dimensional ◽  
Light Sheet ◽  
Rapid Acquisition ◽  
History Of ◽  
The Many ◽  
And Function ◽  
Microbial Systems ◽  
Light Sheet Fluorescence Microscopy

Microbes often live in dense, dynamic, multi-species communities whose architecture and function are intimately intertwined. Imaging these complex, three-dimensional ensembles presents considerable technical challenges, however. In this review, I describe light sheet fluorescence microscopy, a technique that enables rapid acquisition of three-dimensional images over large fields of view and over long durations, and I highlight recent applications of this method to microbial systems that include artificial closed ecosystems, bacterial biofilms, and gut microbiota. I comment also on the history of light sheet imaging and the many variants of the method. Light sheet techniques have tremendous potential for illuminating the workings of microbial communities, a potential that is just beginning to be realized.

scholarly journals Monitoring microbial communities using light sheet fluorescence microscopy

2017 ◽  
Author(s):  
Raghuveer Parthasarathy
Keyword(s):  
Fluorescence Microscopy ◽  
Microbial Communities ◽  
Three Dimensional ◽  
Light Sheet ◽  
Rapid Acquisition ◽  
History Of ◽  
The Many ◽  
And Function ◽  
Microbial Systems ◽  
Light Sheet Fluorescence Microscopy

Microbes often live in dense, dynamic, multi-species communities whose architecture and function are intimately intertwined. Imaging these complex, three-dimensional ensembles presents considerable technical challenges, however. In this review, I describe light sheet fluorescence microscopy, a technique that enables rapid acquisition of three-dimensional images over large fields of view and over long durations, and I highlight recent applications of this method to microbial systems that include artificial closed ecosystems, bacterial biofilms, and gut microbiota. I comment also on the history of light sheet imaging and the many variants of the method. Light sheet techniques have tremendous potential for illuminating the workings of microbial communities, a potential that is just beginning to be realized.

scholarly journals Monitoring microbial communities using light sheet fluorescence microscopy

2017 ◽  
Author(s):  
Raghuveer Parthasarathy
Keyword(s):  
Fluorescence Microscopy ◽  
Microbial Communities ◽  
Three Dimensional ◽  
Light Sheet ◽  
Rapid Acquisition ◽  
History Of ◽  
The Many ◽  
And Function ◽  
Microbial Systems ◽  
Light Sheet Fluorescence Microscopy

Microbes often live in dense, dynamic, multi-species communities whose architecture and function are intimately intertwined. Imaging these complex, three-dimensional ensembles presents considerable technical challenges, however. In this review, I describe light sheet fluorescence microscopy, a technique that enables rapid acquisition of three-dimensional images over large fields of view and over long durations, and I highlight recent applications of this method to microbial systems that include artificial closed ecosystems, bacterial biofilms, and gut microbiota. I comment also on the history of light sheet imaging and the many variants of the method. Light sheet techniques have tremendous potential for illuminating the workings of microbial communities, a potential that is just beginning to be realized.

scholarly journals The 3-Dimensional Distribution of Interstellar Dust

2013 ◽  
Vol 9 (S298) ◽  
pp. 213-220
Author(s):  
Jayant Murthy
Keyword(s):  
Interstellar Dust ◽  
Three Dimensional ◽  
3 Dimensional ◽  
Dust Extinction ◽  
Structure And Morphology ◽  
Current State ◽  
The Galaxy ◽  
Dimensional Distribution ◽  
Color Data ◽  
Dust Distribution

AbstractA knowledge of the three dimensional distribution of interstellar dust is critical in interpreting all observations of the sky, particularly in the understanding of the structure and morphology of our Galaxy. It has been much easier to map the integrated dust extinction through the Galaxy, which is needed in modeling extragalactic sources, but this yields an overestimate of reddening to Galactic objects. Massive surveys, such as Gaia, present both a problem in that the distribution of interstellar dust must be known in order to model the internal structure of the Galaxy and an opportunity in that multi-color data may be used to deconvolve the dust distribution. I will present the current state of the modeling, which is yet in its early stages.

scholarly journals The ISM near SN 1987A: Kinematics and 3-D Structure

1999 ◽  
Vol 190 ◽  
pp. 162-164
Author(s):  
Arlin P.S. Crotts ◽  
Jun Xu
Keyword(s):  
Three Dimensional ◽  
Sn 1987A ◽  
Light Echoes ◽  
History Of

We present two views of the region around SN 1987A: a three-dimensional map of structure revealed by light echoes, and a multicomponent velocity map at 10 km s−1 resolution in [N II], correlating the various superbubble structures found in both, with implications for their age and dynamics, as well as the history of the SN progenitor.

Folds and Refolds

2016 ◽  
pp. 723-743
Author(s):  
Mauro Chiarella
Keyword(s):  
Three Dimensional ◽  
Physical Structure ◽  
Geometric Representation ◽  
Two Dimensional ◽  
Western Thought ◽  
New Developments ◽  
Architectural Space ◽  
The World ◽  
History Of ◽  
Mathematical Calculation

Geometry and architecture both have a long trajectory in the history of western thought. Geometry offers the possibility to interpret the physical structure of the world and to develop rational thinking, while architecture provides the capacity to transform the physical substance and meaning of our surroundings. Diverse developments in the field of geometric representation have determined the characteristics of architectural space: from the modulated rigour of Classicism and the birth of Euclidean geometry, to contemporary informalism with the incorporation of digital mathematical calculation and intense questioning and reconsideration of traditional Cartesian space. The two-dimensional constant and dynamic projection of a three-dimensional spatial situation has been upheld since the time of simple spatial-temporal allegories of the architectural project up until the new developments with unconventional instrumental resources, generating innovative structural, formal, spatial and technological solutions.

Three-dimensional distribution of ribulose-1, 5-bisphosphate carboxylase/oxygemase during the early development of proplastids in dark-grown Euglena cells transferred to an inorganic medium

1990 ◽  
Vol 48 (3) ◽  
pp. 906-907
Author(s):  
Tomoko Ehara ◽  
Shuji Sumida ◽  
Tetsuaki Osafune ◽  
Eiji Hase
Keyword(s):  
Cell Suspension ◽  
Euglena Gracilis ◽  
Carbon Materials ◽  
Three Dimensional ◽  
Peripheral Region ◽  
Plastid Development ◽  
Bisphosphate Carboxylase ◽  
Inorganic Medium ◽  
Ribulose 1 ◽  
Dimensional Distribution

As shown previously, Euglena cells grown in Hutner’s medium in the dark without agitation accumulate wax as well as paramylum, and contain proplastids showing no internal structure except for a single prothylakoid existing close to the envelope. When the cells are transferred to an inorganic medium containing ammonium salt and the cell suspension is aerated in the dark, the wax was oxidatively metabolized, providing carbon materials and energy 23 for some dark processes of plastid development. Under these conditions, pyrenoid-like structures (called “pro-pyrenoids”) are formed at the sites adjacent to the prolamel larbodies (PLB) localized in the peripheral region of the proplastid. The single prothylakoid becomes paired with a newly formed prothylakoid, and a part of the paired prothylakoids is extended, with foldings, in to the “propyrenoid”. In this study, we observed a concentration of RuBisCO in the “propyrenoid” of Euglena gracilis strain Z using immunoelectron microscopy.

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