نتایج جستجو برای: cmb

تعداد نتایج: 5818  

2008
H. K. Eriksen

We provide computationally convenient expressions for all marginal distributions of the polarization CMB power spectrum distribution P (Cl|σl), where Cl = {CTT l , C l , C l , C l } denotes the set of ensemble averaged polarization CMB power spectra, and σl = {σTT l , σ l , σ l , σ l } the set of the realization specific polarization CMB power spectra. This distribution describes the CMB power ...

Journal: :Stroke 2017
José R Romero Sarah R Preis Alexa Beiser Jayandra J Himali Ashkan Shoamanesh Philip A Wolf Carlos S Kase Ramachandran S Vasan Charles DeCarli Sudha Seshadri

BACKGROUND AND PURPOSE Cerebral microbleeds (CMB) represent a common magnetic resonance imaging marker of cerebral small vessel disease, increasingly recognized as a subclinical marker of stroke and dementia risk. CMB detection may reflect the cumulative effect of vascular risk burden and be a marker of higher mortality. We investigated the relation of CMB to risk of death in community dwelling...

2016
Zhi-Yu Zhang Padelis P Papadopoulos R J Ivison Maud Galametz M W L Smith Emmanuel M Xilouris

Images of dust continuum and carbon monoxide (CO) line emission are powerful tools for deducing structural characteristics of galaxies, such as disc sizes, H2 gas velocity fields and enclosed H2 and dynamical masses. We report on a fundamental constraint set by the cosmic microwave background (CMB) on the observed structural and dynamical characteristics of galaxies, as deduced from dust contin...

Journal: :international journal of environmental research 2014
m. al-harbi

this study assesses the air quality of two urban localities, fahaheel and al-rabia city, to assistlocal authorities to generate information supporting the planning of pollution control strategies to keeppollutants within safe limits in the long run. in terms of diurnal and seasonal variations, almost all measured pollutants exhibited two peaks: one in the morning and another in the afternoon. t...

2002
Alessandro Melchiorri

The last years have been an exciting period for the field of the Cosmic Microwave Background (CMB) research. With recent CMB balloon-borne and ground-based experiments we are entering a new era of ’precision’ cosmology that enables us to use the CMB anisotropy measurements to constrain the cosmological parameters and test new theoretical scenarios.

1998
Naoshi Sugiyama

Cosmic Microwave Background (CMB) anisotropies have been recognized as one of the most important observational quantities to understand the early stage of our universe. In this paper, recent development of theoretical works on CMB anisotropies are summarized and it is shown that temperature uctuations of CMB contain rich information, i.e., cosmological parameters, geometry of the universe, init...

2008
M. Frommert T. A. Enßlin

Secondary anisotropies of the cosmic microwave background (CMB) can be detected by using the cross-correlation between the large-scale structure (LSS) and the CMB temperature fluctuations. In such studies, chance correlations of primordial CMB fluctuations with the LSS are the main source of uncertainty. We present a method for reducing this noise by exploiting information contained in the pola...

2004
PAOLO CABELLA

These lectures introduce some of the basic theory of cosmic microwave background (CMB) polarization with the primary aim of developing the theory of CMB polarization from inflationary gravitational waves, as well as some of the related theory of weak gravitational lensing (cosmic shear) of CMB polarization. We begin with production of polarization by Thomson scattering. We then discuss tensor-h...

2001
Aparna Venkatesan

Spectroscopic studies of high-redshift objects combined with increasingly precise data on the cosmic microwave background (CMB) are beginning to place strong bounds on the epoch of hydrogen reionization. Parameter estimation from current CMB data continues, however, to be subject to several degeneracies. Here, we focus on those degeneracies in CMB parameter forecasts related to the optical dept...

2008
J. Chluba

The CMB angular temperature fluctuations observed by Cobe and Wmap enable us to place a lower limit on the spectral distortions of the CMB at any angular scale. These distortions are connected with the simple fact, that the superposition of blackbodies with different temperatures in general is not a blackbody. We show, that in the limit of small temperature fluctuations, the superposition of bl...

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