scholarly journals Galaxy Motions in the Nearby Universe

1996 ◽  
Vol 168 ◽  
pp. 143-155
Author(s):  
John P. Huchra
Keyword(s):  
Virgo Cluster ◽  
Velocity Fields ◽  
Density Field ◽  
Current Status ◽  
Microwave Background ◽  
History Of ◽  
Measured Flow ◽  
Nearby Galaxies ◽  
Cluster 2 ◽  
Hubble Flow

In this paper we review the history of the search for and study of the motions of nearby galaxies with respect to the Hubble Flow. The current status of the field is that (1) convincing infall has been detected into dense clusters, especially the Virgo cluster, (2) the microwave background direction is moderately well aligned with the measured flow nearby but not apparently on larger scales, and (3) there is good but not perfect consistency between the nearby density fields and velocity fields. Particular problems exist in the different Ω's required to fit the density field derived from optically selected and IRAS (60μ) selected galaxy samples.

scholarly journals The Motion of the Local Group of Galaxies with Respect to the Background of Galaxies

1983 ◽  
Vol 104 ◽  
pp. 255-258
Author(s):  
R. D. Davies
Keyword(s):  
Large Scale ◽  
Local Group ◽  
Microwave Background ◽  
Optical Studies ◽  
Group Motion ◽  
Gravitational Influence ◽  
Nearby Galaxies ◽  
Peculiar Motion ◽  
The Universe ◽  
Hubble Flow

A measurement of the motion of the Local Group of galaxies through the Universe provides an indication of their peculiar motion relative to the Hubble flow consequent upon the gravitational influence of the local large scale mass inhomogeneities. This motion can be measured either relative to the cosmic microwave background at z ∼ 1000 or relative to the background or nearby (z ∼ 0.01) galaxies. The interpretation of published measurements is subject to some uncertainty. As an example, the Local Group motion derived from optical studies of nearby galaxies (Rubin et al. 1976) differs from that derived from radio frequency measurements of the dipole anisotropy in the microwave background. (Boughn et al. 1981, Gorenstein & Smoot 1981).

Nonlocal Gravity

2017 ◽  
Author(s):  
Bahram Mashhoon
Keyword(s):  
Gravitational Field ◽  
Gravitational Lensing ◽  
Past History ◽  
Lorentz Invariance ◽  
Minkowski Spacetime ◽  
Field Measurements ◽  
Local Principle ◽  
History Of ◽  
Expansion Of The Universe ◽  
Nearby Galaxies

A postulate of locality permeates through the special and general theories of relativity. First, Lorentz invariance is extended in a pointwise manner to actual, namely, accelerated observers in Minkowski spacetime. This hypothesis of locality is then employed crucially in Einstein’s local principle of equivalence to render observers pointwise inertial in a gravitational field. Field measurements are intrinsically nonlocal, however. To go beyond the locality postulate in Minkowski spacetime, the past history of the accelerated observer must be taken into account in accordance with the Bohr-Rosenfeld principle. The observer in general carries the memory of its past acceleration. The deep connection between inertia and gravitation suggests that gravity could be nonlocal as well and in nonlocal gravity the fading gravitational memory of past events must then be taken into account. Along this line of thought, a classical nonlocal generalization of Einstein’s theory of gravitation has recently been developed. In this nonlocal gravity (NLG) theory, the gravitational field is local, but satisfies a partial integro-differential field equation. A significant observational consequence of this theory is that the nonlocal aspect of gravity appears to simulate dark matter. The implications of NLG are explored in this book for gravitational lensing, gravitational radiation, the gravitational physics of the Solar System and the internal dynamics of nearby galaxies as well as clusters of galaxies. This approach is extended to nonlocal Newtonian cosmology, where the attraction of gravity fades with the expansion of the universe. Thus far only some of the consequences of NLG have been compared with observation.

Recovering the star formation history of galaxies through spectral fitting: Current challenges

2019 ◽  
Vol 15 (S359) ◽  
pp. 386-390
Author(s):  
Lucimara P. Martins
Keyword(s):  
Star Formation ◽  
Mass Function ◽  
Initial Mass Function ◽  
Star Formation History ◽  
Stellar Spectra ◽  
Spectral Fitting ◽  
Formation History ◽  
History Of ◽  
Nearby Galaxies ◽  
Extract Information

AbstractWith the exception of some nearby galaxies, we cannot resolve stars individually. To recover the galaxies star formation history (SFH), the challenge is to extract information from their integrated spectrum. A widely used tool is the full spectral fitting technique. This consists of combining simple stellar populations (SSPs) of different ages and metallicities to match the integrated spectrum. This technique works well for optical spectra, for metallicities near solar and chemical histories not much different from our Galaxy. For everything else there is room for improvement. With telescopes being able to explore further and further away, and beyond the optical, the improvement of this type of tool is crucial. SSPs use as ingredients isochrones, an initial mass function, and a library of stellar spectra. My focus are the stellar libraries, key ingredient for SSPs. Here I talk about the latest developments of stellar libraries, how they influence the SSPs and how to improve them.

scholarly journals Canada’s history of failing to provide medical care for Indigenous children

2020 ◽  
Author(s):  
Rakhshan Kamran
Keyword(s):  
Health Care ◽  
Human Rights ◽  
First Nations ◽  
Social Services ◽  
Current Status ◽  
House Of Commons ◽  
Canadian Government ◽  
Indigenous Children ◽  
History Of ◽  
Services And Supports

Abstract In December 2007, the House of Commons unanimously supported Jordan’s Principle, a commitment that all First Nations children would receive the health care products, social services, and supports, and education they need, in memory of Jordan River Anderson. However, the process of applying for Jordan’s Principle was convoluted and not transparent, leaving several cases not being responded to. The Canadian Human Rights Tribunal found the definition and implementation of Jordan’s Principle to be racist and discriminatory in 2016, ordering the Canadian government to make immediate changes. Failing to make changes to Jordan’s Principle, the Canadian government was found to be noncompliant with the Canadian Human Rights Tribunal orders in 2018. This article provides one case example of Jordan’s Principle that was not responded to, details on the current status of Jordan’s Principle, and information on the recent implementation of the Act respecting First Nations, Inuit and Métis children, youth and families.

scholarly journals Development of an Understanding of Reactive Mercury in Ambient Air: A Review

Atmosphere ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 73
Author(s):  
Mae Sexauer Gustin ◽  
Sarrah M. Dunham-Cheatham ◽  
Jiaoyan Huang ◽  
Steve Lindberg ◽  
Seth N. Lyman
Keyword(s):  
Ambient Air ◽  
Automated System ◽  
Current Status ◽  
Measurement Systems ◽  
Power Plant Emissions ◽  
History Of ◽  
Plant Emissions ◽  
Gas Measurements ◽  
Future Work ◽  
Stack Gas

This review focuses on providing the history of measurement efforts to quantify and characterize the compounds of reactive mercury (RM), and the current status of measurement methods and knowledge. RM collectively represents gaseous oxidized mercury (GOM) and that bound to particles. The presence of RM was first recognized through measurement of coal-fired power plant emissions. Once discovered, researchers focused on developing methods for measuring RM in ambient air. First, tubular KCl-coated denuders were used for stack gas measurements, followed by mist chambers and annular denuders for ambient air measurements. For ~15 years, thermal desorption of an annular KCl denuder in the Tekran® speciation system was thought to be the gold standard for ambient GOM measurements. Research over the past ~10 years has shown that the KCl denuder does not collect GOM compounds with equal efficiency, and there are interferences with collection. Using a membrane-based system and an automated system—the Detector for Oxidized mercury System (DOHGS)—concentrations measured with the KCl denuder in the Tekran speciation system underestimate GOM concentrations by 1.3 to 13 times. Using nylon membranes it has been demonstrated that GOM/RM chemistry varies across space and time, and that this depends on the oxidant chemistry of the air. Future work should focus on development of better surfaces for collecting GOM/RM compounds, analytical methods to characterize GOM/RM chemistry, and high-resolution, calibrated measurement systems.

scholarly journals Shaping Disk Galaxy Stellar Populations via Internal and External Processes

2012 ◽  
Vol 10 (H16) ◽  
pp. 372-372
Author(s):  
Rok Roškar
Keyword(s):  
Galaxy Formation ◽  
Stellar Population ◽  
Milky Way ◽  
Stellar Populations ◽  
Radial Migration ◽  
Disk Formation ◽  
Process Understanding ◽  
History Of ◽  
Nearby Galaxies ◽  
Gas Accretion

AbstractIn recent years, effects such as the radial migration of stars in disks have been recognized as important drivers of the properties of stellar populations. Radial migration arises due to perturbative effects of disk structures such as bars and spiral arms, and can deposit stars formed in disks to regions far from their birthplaces. Migrant stars can significantly affect the demographics of their new locales, especially in low-density regions such as in the outer disks. However, in the cosmological environment, other effects such as mergers and filamentary gas accretion also influence the disk formation process. Understanding the relative importance of these processes on the detailed evolution of stellar population signatures is crucial for reconstructing the history of the Milky Way and other nearby galaxies. In the Milky Way disk in particular, the formation of the thickened component has recently attracted much attention due to its potential to serve as a diagnostic of the galaxy's early history. Some recent work suggests, however, that the vertical structure of Milky Way stellar populations is consistent with models that build up the thickened component through migration. I discuss these developments in the context of cosmological galaxy formation.

Corning Scientific Center in St Petersburg, Russia: The history of its creation, its current status, and its prospects

2001 ◽  
Vol 68 (4) ◽  
pp. 301
Author(s):  
Ch. V. Deneka ◽  
A. V. Dotsenko ◽  
Zh. G. Lemuan ◽  
D. L. Teilor
Keyword(s):  
Current Status ◽  
Scientific Center ◽  
History Of

scholarly journals Cosmic Microwave Background Anisotropy at Degree Angular Scales and the Thermal History of the Universe

1997 ◽  
Vol 480 (1) ◽  
pp. 1-5 ◽  
Author(s):  
Paolo de Bernardis ◽  
Amedeo Balbi ◽  
Giancarlo De Gasperis ◽  
Alessandro Melchiorri ◽  
Nicola Vittorio
Keyword(s):  
Cosmic Microwave Background ◽  
Thermal History ◽  
Microwave Background ◽  
Cosmic Microwave Background Anisotropy ◽  
History Of ◽  
The Universe

Professional Psychology in Portugal

1997 ◽  
Vol 81 (3_suppl) ◽  
pp. 1211-1222 ◽  
Author(s):  
Teresa Fagulha ◽  
Richard H. Dana
Keyword(s):  
Rapid Development ◽  
Well Being ◽  
Professional Psychology ◽  
Current Status ◽  
Environmental Concerns ◽  
Advanced Degrees ◽  
Professional Degree ◽  
History Of ◽  
Training Research

This paper describes the history and current status of professional psychology in Portugal where a unique perspective combines training, research, and practical contributions from Europe and the Americas with their own history of psychological tradition and expertise. Training in professional psychology includes Social Psychology and Educational and Vocational Guidance specializations in addition to Clinical Psychology and Psychotherapy and Counseling for the professional degree, Licenciatura. Advanced degrees are offered in Environmental Psychology, Career Development, Social Cognition, and other areas, primarily for academic positions. Research in all of these areas is expected to have applied outcomes that contribute to individual well being and an improved quality of life for the entire population. The result has been a rapid development of an indigenous professional psychology to address mental health, social, and environmental concerns that compel psychological attention and resources worldwide as well as those problems of local and national origins.

MicroRNA annotation in plants: current status and challenges

2021 ◽  
Author(s):  
Yongxin Zhao ◽  
Zheng Kuang ◽  
Ying Wang ◽  
Lei Li ◽  
Xiaozeng Yang
Keyword(s):  
Small Rna ◽  
Signal To Noise Ratio ◽  
Current Status ◽  
Mirna Biogenesis ◽  
Plant Mirnas ◽  
Signal To Noise ◽  
Advantages And Disadvantages ◽  
Plant Mirna ◽  
History Of ◽  
Mirna Biogenesis Pathway

Abstract Last two decades, the studies on microRNAs (miRNAs) and the numbers of annotated miRNAs in plants and animals have surged. Herein, we reviewed the current progress and challenges of miRNA annotation in plants. Via the comparison of plant and animal miRNAs, we pinpointed out the difficulties on plant miRNA annotation and proposed potential solutions. In terms of recalling the history of methods and criteria in plant miRNA annotation, we detailed how the major progresses made and evolved. By collecting and categorizing bioinformatics tools for plant miRNA annotation, we surveyed their advantages and disadvantages, especially for ones with the principle of mimicking the miRNA biogenesis pathway by parsing deeply sequenced small RNA (sRNA) libraries. In addition, we summarized all available databases hosting plant miRNAs, and posted the potential optimization solutions such as how to increase the signal-to-noise ratio (SNR) in these databases. Finally, we discussed the challenges and perspectives of plant miRNA annotations, and indicated the possibilities offered by an all-in-one tool and platform according to the integration of artificial intelligence.

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