Cosmological 21cm experiments: Searching for a needle in a haystack

There are several planned and ongoing experiments designed to explore the Epoch of Reionization (EoR), the pivotal period during which the gas in the intergalactic medium went from being entirely neutral to almost entirely ionized. These experiments will probe the EoR, through the redshifted 21 cm line from neutral hydrogen, using radio arrays: e.g. Low Frequency Array (LOFAR) and Murchinson Widefield Array (MWA). Unfortunately however, the cosmological 21 cm signal is highly contaminated by astrophysical foregrounds and by non-astrophysical and instrumental effects. Therefore, to reliably detect the cosmological signal, it is essential to understand very well all data components, their influence on the desired signal and explore additional complementary or corroborating probes of the EoR. These proceedings give an overview of observational constrains of the foregrounds, present theoretical efforts to model the foregrounds, and discuss a problem of the foreground removal. The major results are presented for the LOFAR-EoR experiment.Comment: 12 pages, 6 figures, accepted for publication in proceedings of "ISKAF2010 Science Meeting", PoS(ISKAF2010)02

Quench dynamics of the 2d XY model

We investigate the out of equilibrium dynamics of the two-dimensional XY model when cooled across the Berezinskii-Kosterlitz-Thouless (BKT) phase transition using different protocols. We focus on the evolution of the growing correlation length and the density of topological defects (vortices). By using Monte Carlo simulations we first determine the time and temperature dependence of the growing correlation length after an infinitely rapid quench from above the transition temperature to the quasi-long range order region. The functional form is consistent with a logarithmic correction to the diffusive law and it serves to validate dynamic scaling in this problem. This analysis clarifies the different dynamic roles played by bound and free vortices. We then revisit the Kibble-Zurek mechanism in thermal phase transitions in which the disordered state is plagued with topological defects. We provide a theory of quenching rate dependence in systems with the BKT-type transition that goes beyond the equilibrium scaling arguments. Finally, we discuss the implications of our results to a host of physical systems with vortex excitations including planar ferromagnets and liquid crystals as well as the Ginzburg-Landau approach to bidimensional freely decaying turbulence.Comment: 28 pages, 14 figure

Computational screening study towards redox-active metal-organic frameworks

The metal-organic framework (MOF) MFU-4l containing Co(II) centers and Cl- ligands has recently shown promising redox activity. Aiming for further improved MOF catalysts for oxidation processes employing molecular oxygen we present a density-functional theory (DFT) based computational screening approach to identify promising metal center and ligand combinations within the MFU-4l structural family. Using the O2 binding energy as a descriptor for the redox property, we show that relative energetic trends in this descriptor can reliably be obtained at the hybrid functional DFT level and using small cluster (scorpionate-type complex) models. Within this efficient computational protocol we screen a range of metal center / ligand combinations and identify several candidate systems that offer more exothermic O2 binding than the original Co/Cl-based MFU-4l framework.Comment: 9 pages, 4 figure

AGRICULTURAL EXTENSION SERVICE IN THE FUNCTION OF RURAL DEVELOPMENT

Agriculture and agricultural extension service are facing numerous problems in present times when good solutions are not easy to find. Providing of agricultural extension service is important foreign-political instrument of a state which has stimulates the development of agricultural production. Agricultural extension service must provide effective link between holdings-producers, agricultural research and other sources of information. Agricultural extension agents must be aware of psycho-social and social aspects of group action and individual counselling. Therefore, one of priorities in agricultural development of our country is rising of the level of extension operation and establishment of extension service based on modern principles. This is the reason why in this paper, some of the traits of the genesis of extension services were indicated, as well as types of extension services and models of the organization, financing and human resources at disposal and structuring of these resources according to main characteristics, for the purpose of modernization and agricultural and rural development.agricultural extension service, types, models, functioning, human resources, Agribusiness, Community/Rural/Urban Development, Teaching/Communication/Extension/Profession,

COFFE: a code for the full-sky relativistic galaxy correlation function

We present a public version of the code COFFE (COrrelation Function Full-sky Estimator) available at https://github.com/JCGoran/coffe. The code computes the galaxy two-point correlation function and its multipoles in linear perturbation theory, including all relativistic and wide angle corrections. COFFE also calculates the covariance matrix for two physically relevant estimators of the correlation function multipoles. We illustrate the usefulness of our code by a simple but relevant example: a forecast of the detectability of the lensing signal in the multipoles of the two-point function. In particular, we show that lensing should be detectable in the multipoles of the two-point function, with a signal-to-noise larger than 10, in future surveys like Euclid or the SKA.Comment: Code available at https://github.com/JCGoran/coff

Allocation of burden of proof that the arm's length principle was(not) breached under the TFEU Fundamental Freedoms

The topic of this work is the correlation between the protection of tax base by transfer princing rules and EU Law requirements. In particular, the question that wil be dealt with in this paper is how the burdern of proof that the arm's length principle was (not) followed by the taxpayer should be allocated in EU Law Context? Firstly, the EU Law framwork that is relevant for transfer pricing rules of EU Member States will be analyzed. Based on those findings, transfer pricing rules of particular EU Member States will be analyzed in order to determine in what way can the transfer pricing rules of The Member States breach EU Law in relation to the topic of this work

SKA - EoR correlations and cross-correlations: kSZ, radio galaxies, and NIR background

The Universe's Cosmic Dawn (CD) and Epoch of Reionization (EoR) can be studied using a number of observational probes that provide complementary or corroborating information. Each of these probes suffers from its own systematic and statistical uncertainties. It is therefore useful to consider the mutual information that these data sets contain. In this paper, we discuss a potential of cross-correlations between the SKA cosmological 21 cm data with: (i) the kinetic Sunyaev- Zel'dovich (kSZ) effect in the CMB data; (ii) the galaxy surveys; and (iii) near infrared (NIR) backgrounds.Comment: Accepted for publication in the SKA Science Book 'Advancing Astrophysics with the Square Kilometre Array', to appear in 201

Study of Varying Boundary Layer Height on Turret Flow Structures

The Air Force Institute of Technology and the Air Force Research Labs are investigating flows over turrets which are commonly encountered in directed energy integrations with air vehicles. In this work, the computational study was performed using the NASA developed time-marching finite volume code OVERFLOW 2.2 to analyze the effect of boundary layer height on symmetrical and non-symmetrical turret geometries. The effects of aerodynamics yield to the aberration of the laser beam through two methods, aero-optical and aero-mechanical jitter. The analysis of the flow features, pressure fluctuations, density fluctuations, and forces and moments on the various geometries was conducted to predict the impact on the beam quality at low subsonic and transonic speeds. The two flight conditions referred to as low-slow and high-fast where the low-slow flight condition was computed with Mach number of 0.45, Reynolds number of 157,697 per inch (1.892 x 106 per foot), and an altitude of 18,000 feet. The second flight condition referred to as high-fast was set to Mach number of 0.85, Reynolds number of 238,376 per inch (2.86 x 106 per foot), and an altitude of 25,000 feet. The parametric study set up led to 24 cases for comparison of various boundary layer heights between the submerged and exposed turret geometries. The study of flow features indicated that an increase in boundary layer delays the separation and yields to a reduction in the aero-mechanical and aero-optical jitter. For the study of aero-mechanical jitter the pressure fluctuations on the surface of the turret and the flat plate were analyzed to show that an increase in boundary layer reduces the pressure fluctuations in the wake of the geometry