scholarly journals Scintillation Timescales of Bright FRBs Detected by CHIME/FRB

2021 ◽  
Vol 5 (11) ◽  
pp. 271
Author(s):  
Eve Schoen ◽  
Calvin Leung ◽  
Kiyoshi Masui ◽  
Daniele Michilli ◽  
Pragya Chawla ◽  
...  
Keyword(s):  
Strong Correlation ◽  
Characteristic Frequency ◽  
Milky Way ◽  
The Other ◽  
Radio Bursts ◽  
Frequency Structure

Abstract We describe a pipeline to measure scintillation in fast radio bursts (FRBs) detected by CHIME/FRB in the 400–800 MHz band by analyzing the frequency structure of the FRB's spectrum. We use the pipeline to measure the characteristic frequency bandwidths of scintillation between 4–100 kHz in 12 FRBs corresponding to timescales of ∼2–40 μs for 10 FRBs detected by CHIME/FRB. For the other two FRBs, we did not detect scintillation in the region our analysis is sensitive. We compared the measured scintillation timescales to the NE2001 predictions for the scintillation timescales from the Milky Way. We find a strong correlation to be an indication that in most instances, the observed scintillation of FRBs can be explained by the Milky Way.

USE OF THE GALAXY AS A TOOL FOR SPATIAL AND TEMPORAL ORIENTATION DURING THE EARLY ISLAMIC PERIOD AND UP TO THE 15TH CENTURY

2021 ◽  
Vol 31 (1) ◽  
pp. 1-44
Author(s):  
Andreas Eckart
Keyword(s):  
Milky Way ◽  
The Other ◽  
Temporal Orientation ◽  
Islamic Period ◽  
Space And Time ◽  
15Th Century ◽  
Other Hand ◽  
The Galaxy ◽  
Early Islamic Period ◽  
Early Islamic

AbstractWe study to what extent the Milky Way was used as an orientation tool at the beginning of the Islamic period covering the 8th to the 15th century, with a focus on the first half of that era. We compare the texts of three authors from three different periods and give detailed comments on their astronomical and traditional content. The text of al-Marzūqī summarises the information on the Milky Way put forward by the astronomer and geographer ʾAbū Ḥanīfa al-Dīnawarī. The text makes it clear that in some areas the Milky Way could be used as a geographical guide to determine the approximate direction toward a region on Earth or the direction of prayer. In the 15th century, the famous navigator Aḥmad b. Māǧid describes the Milky Way in his nautical instructions. He frequently demonstrates that the Milky Way serves as a guidance aid to find constellations and stars that are useful for precise navigation on land and at sea. On the other hand, Ibn Qutayba quotes in his description of the Milky Way a saying from the famous Bedouin poet Ḏū al-Rumma, which is also mentioned by al-Marzūqī. In this saying the Milky Way is used to indicate the hot summer times in which travelling the desert was particularly difficult. Hence, the Milky Way was useful for orientation in space and time and was used for agricultural and navigational purposes.

Proverbial homogeneity: A cross-linguistic examination of Korean and Indonesian

2014 ◽  
Vol 16 (1) ◽  
pp. 63-81
Author(s):  
Sang-Oak Lee
Keyword(s):  
The Other ◽  
Frequency Data ◽  
Corpus Linguistic ◽  
Cultural Life ◽  
Frequency Structure ◽  
Other Hand ◽  
The Last Two Millennia

This study explores the use of keywords in proverbs in Korean, English, Chinese, and Indonesian. The study applies the traditional corpus linguistic tools of frequency and ranking to the keywords found in proverbs in an attempt to characterize the proverbs of these languages. The frequency data show that English proverbs are dominated by abstract keywords like “love, God, age, foolishness, wisdom, poverty, good, evil, and truth.” On the other hand, Chinese proverbs are dominated by more “action oriented” and “pragmatic concern” keywords such as “heart, time, talk/say, act/do, words, method, and knowledge,” showing a clear divergence from the frequency structure of English proverb keywords. Surprisingly, Korean proverb keywords, just like the English keywords, are also found to share very little in common with Chinese, a longstanding neighbor which has strongly influenced the cultural life of Korea over the last two millennia. Instead, the data show that the proverb keyword structure most resembles that of Indonesian, both having material/physical terms dominating the keywords and both sharing three common top-ranking keywords: water, dog, and cow.

Coupled systems of two-dimensional turbulence

2013 ◽  
Vol 732 ◽  
Author(s):  
Rick Salmon
Keyword(s):  
Hamiltonian System ◽  
Energy Conservation ◽  
Strong Correlation ◽  
Conservation Law ◽  
Hamiltonian Dynamics ◽  
Coupled Systems ◽  
The Other ◽  
Two Dimensional ◽  
Coherent Vortices ◽  
Fluid Particles

AbstractOrdinary two-dimensional turbulence corresponds to a Hamiltonian dynamics that conserves energy and the vorticity on fluid particles. This paper considers coupled systems of two-dimensional turbulence with three distinct governing dynamics. One is a Hamiltonian dynamics that conserves the vorticity on fluid particles and a quantity analogous to the energy that causes the system members to develop a strong correlation in velocity. The other two dynamics considered are non-Hamiltonian. One conserves the vorticity on particles but has no conservation law analogous to energy conservation; the other conserves energy and enstrophy but it does not conserve the vorticity on fluid particles. The coupled Hamiltonian system behaves like two-dimensional turbulence, even to the extent of forming isolated coherent vortices. The other two dynamics behave very differently, but the behaviours of all four dynamics are accurately predicted by the methods of equilibrium statistical mechanics.

On the Nature of Weak Spots in High-k Layers Submitted to Anneals

2004 ◽  
Vol 811 ◽  
Author(s):  
J. Pétry ◽  
W. Vandervorst ◽  
O. Richard ◽  
T. Conard ◽  
P. DeWolf ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Strong Correlation ◽  
Positive Charge ◽  
The Other ◽  
Physical Analysis ◽  
Force Microscopy ◽  
Atomic Force ◽  
Other Hand ◽  
High K ◽  
High K Dielectric

ABSTRACTIn the path to the introduction of high-k dielectric into IC components, a large number of challenges have still to be solved. Some of the major issues concern the low mobility of carriers and the reliability of the devices. Trapped charges in the stack have been identified as being the cause of these issues. With this in mind, we used Conducting Atomic Force Microscopy, combined with physical analysis to understand the nature of these charges. In this contribution, we have studied the uniformity of thin HfO2 layers, with and without anneal. The Conducting Atomic Force microscopy measurements show spots of higher conductivity. Recording local IV's in those ‘weak’ spots suggests that they consist of positive charge. On the other hand, XPS and ToFSIMS analysis show a diffusion of the interfacial SiO2 upwards into the high-k layer. Finally, the comparison of samples with differing high-k material and crystallinity indicates a strong correlation between the weak spots and the presence of silicon in the film.

scholarly journals Which one to trust? Exploratory analysis on astrology, science and religiosity among students in Bucharest

2021 ◽  
Vol 19 (1) ◽  
pp. 117-133
Author(s):  
Dragoș Obreja
Keyword(s):  
University Students ◽  
Negative Correlation ◽  
Strong Correlation ◽  
Statistical Significance ◽  
The Other ◽  
Contemporary Society ◽  
Negative Relation ◽  
Probability Sample ◽  
And Mathematics ◽  
Moderate Positive Correlation

Confidence in astrology remains a visible phenomenon in contemporary society, and this is a constant topic of academic interest. A survey based on 512 valid questionnaires were obtained from a non-probability sample of university students from Bucharest, in order to observe possible statistical relations between confidence in astrology, confidence in sciences such as medicine and mathematics, but also fields such as astronomy and horoscope. On the other hand, several statements have been used to measure the level of religiosity. Notable is the moderate positive correlation obtained between astrology and astronomy, but also the strong correlation between astrology and horoscope (this last correlation was expected). Broadly speaking, it is observed that astrology correlates positively with the variables that constitute the ‘inward’ component of religiosity, while the ‘outward’ component shows a rather negative correlation, but which does not enjoy a similar statistical significance. Astronomy, like medicine, outlines negative relation with the level of religiosity. Instead, the correlations that involve trust in medicine have a negative and moderate value, in relation to religiosity. In conclusion, it is observed that the trust in “strong sciences” generates more prompt correlations compared to the trust in astrology, while further studies are needed to clarify the reasons for such uncertain correlations between astrology and religiosity.

scholarly journals High-Velocity Clouds and the Local Group

2004 ◽  
Vol 217 ◽  
pp. 2-11 ◽  
Author(s):  
B. P. Wakker
Keyword(s):  
High Velocity ◽  
Milky Way ◽  
Local Group ◽  
Current Data ◽  
The Other ◽  
Hot Gas ◽  
Neutral Gas ◽  
Hα Emission ◽  
M 31 ◽  
High Velocity Clouds

I examine some of the evidence relevant to the idea that high-velocity clouds (HVCs) are gas clouds distributed throughout the Local Group, as proposed by Blitz et al. (1999) and Braun & Burton (1999). This model makes several predictions: a) the clouds have low metallicities; b) there should be no detectable Hα emission; c) analogues near other galaxies should exist; and d) many faint HVCs in the region around M 31 can be found. Low metallicities are indeed found in several HVCs, although they are also expected in several other models. Hα emission detected in most HVCs and, when examined more closely, distant (D>200 kpc) HVCs should be almost fully ionized, implying that most HVCs with H I must lie near the Milky Way. No clear extragalactic analogues have been found, even though the current data appear sensitive enough. The final prediction (d) has not yet been tested. on balance there appears to be no strong evidence for neutral gas clouds distributed throughout the Local Group, but there may be many such clouds within 100 or so kpc from the Milky Way (and M31). on the other hand, some (but not all) of the high-velocity O VI recently discovered may originate in hot gas distributed throughout the Local Group.

scholarly journals The Milky Way: summary and outlook

1985 ◽  
Vol 106 ◽  
pp. 635-639
Author(s):  
Jeremiah P. Ostriker
Keyword(s):  
Empirical Evidence ◽  
Milky Way ◽  
Oblate Spheroid ◽  
The Other ◽  
Human Thought ◽  
Conspicuous Feature ◽  
Other Hand ◽  
Absorption Of Light ◽  
The Galaxy ◽  
The One

First let me review the historical discussions presented during our symposium: the papers by Paul, Gingerich, Hoskin and Smith. I was greatly impressed by the power of abstract human thought in its confrontation with resistant reality. On the one hand we see again and again extraordinary prescience, where abstract beliefs based on little or no empirical evidence–like the island-universe hypothesis–turn out to be, in their essentials, true. Clearly, we often know more than we know that we know. On the other hand, there are repeated instances of resistance to the most obvious truth due to ingrained beliefs. These may be termed conspiracies of silence. Van Rhijn and Shapley agreed about few things. But one of them was that there was no significant absorption of light in the Galaxy. Yet the most conspicuous feature of the night sky is the Milky Way, and the second most conspicuous feature is the dark rift through its middle. What looks to the most untutored eye like a “sandwich” was modeled as an oblate spheroid. These eminent scientists must have known about the rift, but somehow wished it away in their analyses. I find that very curious. Other examples from earlier times abound. We all know that the Crab supernova was seen from many parts of the globe but, though it was bright enough to be detected by the unaided eye in daylight, its existence was never–so far as we know–recorded in Europe. It did not fit in with the scheme of things, so it was not seen.

scholarly journals The Moyjil site, south-west Victoria, Australia: fire and environment in a 120,000-year coastal midden — nature or people?

2018 ◽  
Vol 130 (2) ◽  
pp. 71 ◽  
Author(s):  
Jim M. Bowler ◽  
David M. Price ◽  
John E. Sherwood ◽  
Stephen P. Carey
Keyword(s):  
Magnetic Susceptibility ◽  
Strong Correlation ◽  
The Other ◽  
Last Interglacial ◽  
Human Occupation ◽  
Thermal Alteration ◽  
South West ◽  
Eastern Australia ◽  
Dark Staining ◽  
Mis 5E

At Moyjil (Point Ritchie), a cliffed site at the mouth of the Hopkins River at Warrnambool, south-eastern Australia, an erosional disconformity of Last Interglacial age on both a rock stack and the adjacent headland represents a surface of possible human occupation. Shells of edible marine molluscs occur on the disconformity, together with a distinctive population of transported stones derived from a calcrete of MIS 7 age and bearing variable dark grey to near-black colouration suggestive of fire. Experimental fire produced similar thermal alteration of calcrete. A strong correlation exists between intensity and depth of dark staining on one hand and increased magnetic susceptibility on the other. Thermal luminescence analyses of blackened stones provide ages in the MIS 5e range, 100–130 ka, consistent with independent stratigraphic evidence and contemporaneous with the age of the surface on which they lie. The distribution of fire-darkened stones is inconsistent with wildfire effects. Two hearth-like features closely associated with the disconformity provide further indications of potential human agency. The data are consistent with the suggestion of human presence at Warrnambool during the Last Interglacial.

scholarly journals High reddening patches in Gaia DR2

2020 ◽  
Vol 634 ◽  
pp. A33
Author(s):  
Leire Beitia-Antero ◽  
Ana Inés Gómez de Castro ◽  
Raúl de la Fuente Marcos
Keyword(s):  
Star Formation ◽  
Milky Way ◽  
Spectroscopic Analysis ◽  
Galactic Halo ◽  
Spiral Galaxies ◽  
Monte Carlo Sampling ◽  
The Other ◽  
Host Galaxies ◽  
Galactic Model ◽  
Gaia Dr2

Context. Deep GALEX UV data show that the extreme outskirts of some spiral galaxies are teeming with star formation. Such young stellar populations evolving so far away from the bulk of their host galaxies challenge our overall understanding of how star formation proceeds at galactic scales. It is at present unclear whether our own Milky Way may also exhibit ongoing and recent star formation beyond the conventional edge of the disk (∼15 kpc). Aims. Using Gaia DR2 data, we aim to determine if such a population is present in the Galactic halo, beyond the nominal radius of the Milky Way disk. Methods. We studied the kinematics of Gaia DR2 sources with parallax values between 1/60 and 1/30 milliarcseconds towards two regions that show abnormally high values of extinction and reddening; the results are compared with predictions from GALAXIA Galactic model. We also plotted the color–magnitude (CM) diagrams with heliocentric distances computed inverting the parallaxes, and studied the effects of the large parallax errors by Monte Carlo sampling. Results. The kinematics point towards a Galactic origin for one of the regions, while the provenance of the stars in the other is not clear. A spectroscopic analysis of some of the sources in the first region confirms that they are located in the halo. The CM diagram of the sources suggests that some of them are young.

A precise worldwide correlation of early Ordovician graptolite sequences

1990 ◽  
Vol 127 (6) ◽  
pp. 497-525 ◽  
Author(s):  
R. A. Cooper ◽  
K. Lindholm
Keyword(s):  
Strong Correlation ◽  
The Other ◽  
Data Sets ◽  
Early Ordovician ◽  
Standard Sequence ◽  
The World ◽  
Species Groups ◽  
Stratigraphic Ranges ◽  
High Level

AbstractFourteen early Ordovician (Tremadoc-Llandeilo) graptolite sequences from around the world are precisely (infrazonally) correlated, based on the stratigraphic ranges of 130 species and species groups. The composite standard sequence (CSS) of graptolites has been determined from the six best regional sequences by a nonparametric graphic correlation. Two data sets were selected: one comprised first appearance events of 103 taxa, the other, first and last appearance events of 45 taxa. The results of the two runs accord well and reveal respectively 66 and 73 successive bioevents in early Ordovician time. Event spacing averages 0.7–0.8 Ma and enables fine subdivision, correlation and homotaxial testing for diachroneity. The strong correlation between each of the six regional sequences and the CSS indicates the high level of accordance among graptolite successions around the world.

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