Development and Application of Luminescence to Earth and Planetary Sciences: Some Landmarks

2014 ◽  
Vol 357 ◽  
pp. 217-243
Author(s):  
R.H. Biswas
Keyword(s):  
Numerical Models ◽  
Cosmic Ray ◽  
Time Resolved ◽  
Infrared Stimulated Luminescence ◽  
Accuracy And Precision ◽  
Wide Range ◽  
History Of ◽  
Recent Trends ◽  
User Friendly ◽  
Exposure Ages

Luminescence, mainly thermoluminescence (TL) and optically stimulated luminescence (OSL), has been researched for more than five decades towards its application to earth and planetary sciences. Luminescence production mechanism has been understood through several theoretical studies, like analytical kinetic theory, numerical models along with the experimental results. Instrument development has progressed with aim from user friendly TL/OSL reader dedicated for dating to challenging reader forin-situMartian sediment dating. Since the development of optical dating in 1985, the technique revolutionised the research in earth sciences. And since then to recent, many methodologies have been developed and some are in developing stage using different signals, like, single grain OSL, red TL, time resolved OSL, thermally transferred OSL (TT-OSL), post infrared-infrared stimulated luminescence (pIR-IRSL), violet light stimulated luminescence (VSL), infrared radioluminescence (IRRL), etc. with an objective to improve the accuracy and precision and to extend the dating range. The wide range of application in different environment, e.g. aeolian, fluvial, marine, glacier, soil, volcanic materials, heated materials, shocked materials, meteorites, etc. have made the technique successful to understand the quaternary history of earth and planetary information like terrestrial and cosmic ray exposure ages of meteorite, meteoroid orbit, thermal metamorphism history of meteorite etc. The aim of this present paper is to discuss some landmarks and recent trends in the development and application in these areas. Contents of the Paper

scholarly journals Interstellar and intergalactic dynamos

2012 ◽  
Vol 8 (S294) ◽  
pp. 225-236
Author(s):  
M. Hanasz ◽  
D. Woltanski ◽  
K. Kowalik
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Large Scale ◽  
Numerical Models ◽  
Rotation Period ◽  
Cosmic Ray ◽  
Small Scale ◽  
Galactic Rotation ◽  
Galaxy Mergers ◽  
Wide Range

AbstractWe review recent developments of amplification models of galactic and intergalactic magnetic field. The most popular scenarios involve variety of physical mechanisms, including turbulence generation on a wide range of physical scales, effects of supernovae, buoyancy as well as the magnetorotational instability. Other models rely on galaxy interaction, which generate galactic and intergalactic magnetic fields during galaxy mergers. We present also global galactic-scale numerical models of the Cosmic Ray (CR) driven dynamo, which was originally proposed by Parker (1992). We conduct a series of direct CR+MHD numerical simulations of the dynamics of the interstellar medium (ISM), composed of gas, magnetic fields and CR components. We take into account CRs accelerated in randomly distributed supernova (SN) remnants, and assume that SNe deposit small-scale, randomly oriented, dipolar magnetic fields into the ISM. The amplification timescale of the large-scale magnetic field resulting from the CR-driven dynamo is comparable to the galactic rotation period. The process efficiently converts small-scale magnetic fields of SN-remnants into galactic-scale magnetic fields. The resulting magnetic field structure resembles the X-shaped magnetic fields observed in edge-on galaxies.

scholarly journals Quantifying pigment cover to assess variation in animal colouration

2017 ◽  
Vol 2 (1) ◽  
Author(s):  
Andjin Siegenthaler ◽  
Debapriya Mondal ◽  
Chiara Benvenuto
Keyword(s):  
High Precision ◽  
Digital Images ◽  
Behavioural Ecology ◽  
Crangon Crangon ◽  
Accuracy And Precision ◽  
Wide Range ◽  
Pigment Migration ◽  
Animal Colouration ◽  
User Friendly ◽  
Speed Accuracy

Abstract The study of animal colouration addresses fundamental and applied aspects relevant to a wide range of fields, including behavioural ecology, environmental adaptation and visual ecology. Although a variety of methods are available to measure animal colours, only few focus on chromatophores (specialized cells containing pigments) and pigment migration. Here, we illustrate a freely available and user-friendly method to quantify pigment cover (PiC) with high precision and low effort using digital images, where the foreground (i.e. pigments in chromatophores) can be detected and separated from the background. Images of the brown shrimp, Crangon crangon, were used to compare PiC with the traditional Chromatophore Index (CI). Results indicate that PiC outcompetes CI for pigment detection and transparency measures in terms of speed, accuracy and precision. The proposed methodology provides researchers with a useful tool to answer essential physiological, behavioural and evolutionary questions on animal colouration in a wide range of species.

Eisenmeteorite als Raumsonden für die Untersuchung des Intensitätsverlaufes der kosmischen Strahlung während der letzten Milliarden Jahre

1962 ◽  
Vol 17 (5) ◽  
pp. 422-432 ◽  
Author(s):  
H. Voshage
Keyword(s):  
Interplanetary Space ◽  
Cosmic Ray ◽  
Gas Production ◽  
Rare Gas ◽  
Rare Gases ◽  
Production Rates ◽  
Cosmic Ray Intensity ◽  
Long Time ◽  
History Of ◽  
Exposure Ages

The use of iron meteorites for the establishment of possible long-time variations (108 —109 years) of the cosmic ray intensity in interplanetary space is based upon the study of the production rates of nuclides which are formed by the interaction of cosmic ray particles with nuclei in meteorites. Mass spectrometric measurements of the isotopic composition of meteoritic potassium * are combined with data on cosmogenic rare gases and other elements to give K41-K40-exposure ages and rare gas production rates. The K41-K40-exposure ages are larger than the exposure ages obtained from the study of short-lived activities (e. g. Cl36, A39), by a factor 1.3 to 1.8. This result indicates that the cosmic ray intensity increased during the bombardment history of the meteorites. The data, for example, are consistent with the following assumptions: 1) The cosmic ray intensity was constant during most of the bombarding time and increased by a factor of about 1.5 only a few million years ago. 2) The intensity rose as I(t) =I0 e— γt with —1.1·10-9 ≦ γ ≦ —0.6 · 10-9 a–1. The consequences of this result for the interpretation of meteorite data are discussed.

Cosmic-ray exposure ages of diogenites and the recent collisional history of the howardite, eucrite and diogenite parent body/bodies

1997 ◽  
Vol 32 (6) ◽  
pp. 891-902 ◽  
Author(s):  
KEES C. WELTEN ◽  
LOUIS LINDNER ◽  
KLAAS BORG ◽  
THOMAS LOEKEN ◽  
PETER SCHERER ◽  
...  
Keyword(s):  
Cosmic Ray ◽  
Parent Body ◽  
History Of ◽  
Exposure Ages ◽  
Cosmic Ray Exposure Ages

Cosmogenic Nuclides

2020 ◽  
Author(s):  
Rainer Wieler
Keyword(s):  
Noble Gas ◽  
Cosmic Ray ◽  
Parent Body ◽  
Cosmogenic Nuclides ◽  
Cosmogenic Nuclide ◽  
Production Models ◽  
History Of ◽  
Noble Gas Isotopes ◽  
Exposure Ages

Cosmogenic nuclides are produced by the interaction of energetic elementary particles of galactic (or solar) cosmic radiation and their secondaries with atomic nuclei in extraterrestrial or terrestrial material. Cosmogenic nuclides usually are observable only for some noble gas isotopes, whose natural abundances in the targets of interest are exceedingly low; some radioactive isotopes with half-lives mostly in the million-year range; and a few stable nuclides of elements, such as Gd and Sm, whose abundance is sizably modified by reactions with low energy secondary cosmic ray neutrons. In solid matter, the mean attenuation length of galactic cosmic ray protons is on the order of 50 cm. Therefore, cosmogenic nuclides are a major tool in studying the history of small objects in space and of matter near the surfaces of larger parent bodies. A classical application is to measure “exposure ages” of meteorites, namely the time they spent as a small body in interplanetary space. In some cases, also the previous history of the future meteorite in its parent-body regolith can be constrained. Such information helps to understand delivery mechanisms of meteorites from their parent asteroids or parent planets and to constrain the number of ejection events responsible for the collected meteorites. Cosmogenic nuclides in lunar samples from known depths of up to ~2 m serve to study the deposition and mixing history of the lunar regolith over hundreds of millions of years, as well as to calibrate nuclide production models. Present and future sample return missions rely on cosmogenic nuclide measurements as important tools to constrain the sample’s exposure history or loss rates of their parent body surfaces to space. The first data from cosmogenic noble gas isotopes measured on the surface of Mars demonstrate that the exposure and erosional history of planetary bodies can be obtained by in-situ analyses. For the foreseeable future, exposure ages of presolar grains in meteorites are presumably the only means to quantitatively constrain their presolar history. In some cases, irradiation effects of energetic particles from the early sun can be detected in early solar system condensates, confirming that the early sun was likely much more active than today, as expected from observations of young stars. The ever-increasing precision of isotope analyses also reveals tiny isotopic anomalies induced by cosmic-ray effects in several elements of interest in cosmochemistry, which need to be recognized and corrected for. Cosmogenic nuclide studies rely on the knowledge of their production rates, which depend on the elemental composition of a sample and its “shielding” during irradiation, that is, its position within an irradiated object and for meteorites their preatmospheric size. The physics of cosmogenic nuclide production is basically well understood and has led to sophisticated production models. They are most successful if a sample’s shielding can be constrained by the analyses of several cosmogenic nuclides with different depth dependencies of their production rates. Cosmogenic nuclides are also an important tool in Earth Sciences. The foremost example is 14C produced in the atmosphere and incorporated into organic material, which is used for dating. Cosmogenic radionuclides and noble gases produced in-situ in near surface samples, mostly by secondary cosmic-ray neutrons, are an important tool in quantitative geomorphology and related fields.

scholarly journals Pervasive subduction zone devolatilization recycles CO2 into the forearc

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
E. M. Stewart ◽  
Jay J. Ague
Keyword(s):  
Numerical Models ◽  
Chemical System ◽  
Water Mobility ◽  
Carbon Loss ◽  
Geologic Time ◽  
Direct Observations ◽  
Wide Range ◽  
History Of ◽  
The Subject ◽  
Subducting Slab

AbstractThe fate of subducted CO2 remains the subject of widespread disagreement, with different models predicting either wholesale (up to 99%) decarbonation of the subducting slab or extremely limited carbon loss and, consequently, massive deep subduction of CO2. The fluid history of subducted rocks lies at the heart of this debate: rocks that experience significant infiltration by a water-bearing fluid may release orders of magnitude more CO2 than rocks that are metamorphosed in a closed chemical system. Numerical models make a wide range of predictions regarding water mobility, and further progress has been limited by a lack of direct observations. Here we present a comprehensive field-based study of decarbonation efficiency in a subducting slab (Cyclades, Greece), and show that ~40% to ~65% of the CO2 in subducting crust is released via metamorphic decarbonation reactions at forearc depths. This result precludes extensive deep subduction of most CO2 and suggests that the mantle has become more depleted in carbon over geologic time.

Multiple phase transitions investigated by high-speed TEM

1990 ◽  
Vol 48 (4) ◽  
pp. 550-551
Author(s):  
Oleg Bostanjoglo ◽  
Peter Thomsen-Schmidt
Keyword(s):  
Phase Transitions ◽  
High Speed ◽  
Short Exposure ◽  
Semiconductor Film ◽  
Time Resolved ◽  
Short Exposure Time ◽  
Multiple Phase ◽  
Model Substance ◽  
History Of ◽  
Electron Image

Thin GexTe1-x (x = 0.15-0.8) were studied as a model substance of a composite semiconductor film, in addition being of interest for optical storage material. Two complementary modes of time-resolved TEM were used to trace the phase transitions, induced by an attached Q-switched (50 ns FWHM) and frequency doubled (532 nm) Nd:YAG laser. The laser radiation was focused onto the specimen within the TEM to a 20 μm spot (FWHM). Discrete intermediate states were visualized by short-exposure time doubleframe imaging /1,2/. The full history of a transformation was gained by tracking the electron image intensity with photomultiplier and storage oscilloscopes (space/time resolution 100 nm/3 ns) /3/. In order to avoid radiation damage by the probing electron beam to detector and specimen, the beam is pulsed in this continuous mode of time-resolved TEM,too.Short events ( <2 μs) are followed by illuminating with an extended single electron pulse (fig. 1c)

Group Experiences and Individual Differences in Stuttering

2019 ◽  
Vol 62 (12) ◽  
pp. 4335-4350 ◽  
Author(s):  
Seth E. Tichenor ◽  
J. Scott Yaruss
Keyword(s):  
Individual Differences ◽  
Support Groups ◽  
Support Group ◽  
Affective States ◽  
Life Outcomes ◽  
Self Help ◽  
Wide Range ◽  
Group Experiences ◽  
History Of ◽  
Adults Who Stutter

Purpose This study explored group experiences and individual differences in the behaviors, thoughts, and feelings perceived by adults who stutter. Respondents' goals when speaking and prior participation in self-help/support groups were used to predict individual differences in reported behaviors, thoughts, and feelings. Method In this study, 502 adults who stutter completed a survey examining their behaviors, thoughts, and feelings in and around moments of stuttering. Data were analyzed to determine distributions of group and individual experiences. Results Speakers reported experiencing a wide range of both overt behaviors (e.g., repetitions) and covert behaviors (e.g., remaining silent, choosing not to speak). Having the goal of not stuttering when speaking was significantly associated with more covert behaviors and more negative cognitive and affective states, whereas a history of self-help/support group participation was significantly associated with a decreased probability of these behaviors and states. Conclusion Data from this survey suggest that participating in self-help/support groups and having a goal of communicating freely (as opposed to trying not to stutter) are associated with less negative life outcomes due to stuttering. Results further indicate that the behaviors, thoughts, and experiences most commonly reported by speakers may not be those that are most readily observed by listeners.

Introduction: Emotion, History and the Arts

2018 ◽  
Vol 7 (2) ◽  
pp. 117-128 ◽  
Author(s):  
Erin Sullivan ◽  
Marie Louise Herzfeld-Schild
Keyword(s):  
Historical Change ◽  
Carson Mccullers ◽  
Emotional Life ◽  
Review Section ◽  
The Arts ◽  
Wide Range ◽  
War Correspondents ◽  
History Of ◽  
Johan Huizinga

This introduction surveys the rise of the history of emotions as a field and the role of the arts in such developments. Reflecting on the foundational role of the arts in the early emotion-oriented histories of Johan Huizinga and Jacob Burkhardt, as well as the concerns about methodological impressionism that have sometimes arisen in response to such studies, the introduction considers how intensive engagements with the arts can open up new insights into past emotions while still being historically and theoretically rigorous. Drawing on a wide range of emotionally charged art works from different times and places—including the novels of Carson McCullers and Harriet Beecher-Stowe, the private poetry of neo-Confucian Chinese civil servants, the photojournalism of twentieth-century war correspondents, and music from Igor Stravinsky to the Beatles—the introduction proposes five ways in which art in all its forms contributes to emotional life and consequently to emotional histories: first, by incubating deep emotional experiences that contribute to formations of identity; second, by acting as a place for the expression of private or deviant emotions; third, by functioning as a barometer of wider cultural and attitudinal change; fourth, by serving as an engine of momentous historical change; and fifth, by working as a tool for emotional connection across communities, both within specific time periods but also across them. The introduction finishes by outlining how the special issue's five articles and review section address each of these categories, while also illustrating new methodological possibilities for the field.

History of the Study of Apocrypha in Early Medieval England

2020 ◽  
Vol 48 (3-4) ◽  
pp. 13-26
Author(s):  
Brandon W. Hawk
Keyword(s):  
Old Testament ◽  
Medieval England ◽  
Medieval Period ◽  
Early Medieval ◽  
Future Directions ◽  
Early Judaism ◽  
Wide Range ◽  
History Of ◽  
The Subject ◽  
Early English

Literature written in England between about 500 and 1100 CE attests to a wide range of traditions, although it is clear that Christian sources were the most influential. Biblical apocrypha feature prominently across this corpus of literature, as early English authors clearly relied on a range of extra-biblical texts and traditions related to works under the umbrella of what have been called “Old Testament Pseudepigrapha” and “New Testament/Christian Apocrypha." While scholars of pseudepigrapha and apocrypha have long trained their eyes upon literature from the first few centuries of early Judaism and early Christianity, the medieval period has much to offer. This article presents a survey of significant developments and key threads in the history of scholarship on apocrypha in early medieval England. My purpose is not to offer a comprehensive bibliography, but to highlight major studies that have focused on the transmission of specific apocrypha, contributed to knowledge about medieval uses of apocrypha, and shaped the field from the nineteenth century up to the present. Bringing together major publications on the subject presents a striking picture of the state of the field as well as future directions.

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