The Light-cone Effect on the Clustering Statistics in the Cosmological Redshift Space

We present a theoretical formalism to predict the two-point clustering statistics (the power spectrum and the two-point correlation function), simultaneously taking account of the linear velocity distortion, the nonlinear velocity distortion (finger-of-god), the cosmological redshift-space distortion and the light-cone effect. To demonstrate the importance of these effects in exploring the clustering of objects at high redshifts, we show several model predictions for magnitude-limited surveys of galaxies and quasars. This methodology provides a quantitative tool to confront theoretical models against the upcoming precision data on clustering in the universe.Comment: 8 pages, 3 figures, accepted for publication in PASJ (2000

Effect of garnet waste on the properties of foamed concrete

The research is aimed to produce foamed concrete blocks viable for nonstructural applications. This paper reports the studied effect of garnet waste on the properties of foamed concrete. Garnet waste was used to replace fine aggregates (sand) at different percentages (20%, 40%, 60%, 80% and 100%). The various mixes were checked for fresh properties (workability and plastic density of mortar and foamed concrete) and consequent compressive strength test was carried out on cube and block specimens. The results have shown increment in workability with respect to increase in garnet content. The best replacement producing the best compressive strength is that containing 20% spent garnet waste replacing fine aggregates (sand). The mix has added up to 15 % in cube compressive strength and 12% in block compressive strength. However, replacing 100% fine aggregates (sand) with spent garnet waste for foamed concrete is not possible due to probable chemical reaction between synthetic foaming agent and garnet waste disallowing proper bond between cement and garnet waste

Deciphering cosmological information from redshift surveys of high-z objects - the cosmological light-cone effect and redshift-space distortion -

The three-dimensional distribution of astronomical objects observed in redshift space significantly differs from the true distribution since the distance to each object cannot be determined by its redshift $z$ only; for $z \ll 1$ the peculiar velocity field contaminates the true recession velocity of the Hubble flow, while the true distance for objects at $z < 1$ sensitively depends on the (unknown and thus assumed) cosmological parameters. This hampers the effort to understand the true distribution of large-scale structure of the universe. In addition, all cosmological observations are carried out on a light-cone, the null hypersurface of an observer at $z=0$. This implies that their intrinsic properties and clustering statistics should change even within the survey volume. Therefore a proper comparison taking account of the light-cone effect is important to extract any cosmological information from redshift catalogues, especially for $z < 1$. We present recent theoretical development on the two effects -- the cosmological light-cone effect and the cosmological redshift-space distortion -- which should play key roles in observational cosmology in the 21st century.Comment: 28pages, 20 figures, minor revision to match the final version to appear in Progress of Theoretical Physics Supplement, vol. 133 (1999

The intention to adopt model of infrastructure as a service-based e-learning in higher education institutions in Nigeria

The global demand for providing education for all in the context of Nigerian Higher Education Institutions signifies the urgent need for an effective and efficient method of delivering e-learning content. Presently, the developed countries are adopting Cloud-Based e-learning for its cost reduction, security, scalability, and the availability of e-learning content 24/7. However, the lack of adoption of the Infrastructure as-a Service-Based E-learning faces a threat to the availability and sustainability of e-learning in Nigeria. Thus, the limited studies on its adoption further demonstrate this. Therefore, this study aims to investigate the factors that influence the Intention to adopt IaaSBEL from the perspective of the ICT directorates top managers. PLS-SEM was used to analyse the data generated from the questionnaire, while interview data were analysed using a thematic approach. The statistical results demonstrated that Relative Advantage, Cost Savings, Service Provider Support, and Government Support were significantly supported while Compatibility, Trust, Security, Top Management Support, and Competitive Pressure were not supported. The moderating variable (Government Support) statistical results show that Relative Advantage was positively supported while Cost Savings and Trust were negatively supported. The findings of this study further demonstrated the significance of the adopted variables as capable of influencing the perception of ICT directorates’ top managers' Intention to adopt the IaaSBEL model based on the TOE and DOI theories, with the addition of other external variables. However, the study observed some limitations with regards to the ICT infrastructure and policies in attaining education for all in Nigeria despite gender, financial, and location constraints. The study further contributes to the theory and practice of IS as well as recommendations to policy makers and cloud vendors. Also, effective e-learning would be available to staff and students towards reducing the budgetary constraints, hence, impacting the society

Linguistic image of the Kazakh worldview in the national ornament

Introduction: Today a comprehensive study of the Kazakh craft is of great importance both for science and for life experience. In the third millennium, the self-identification of the peoples of the world reached a new level of research. National properties are not only monuments, but appear as objects of research through various spectrums of scientific perception. The purpose of our article is to study the linguistic representation of the Kazakh worldview in the national ornament. Materials and Methods: Along with the methods of accumulation and differentiation, the methods of comparative historical analysis are used in the research work. Results and Discussion: The problem of reflecting the linguistic picture of the world in the national ornament, which is a rich heritage of the people, a symbol of their culture, an example of the works of masters is considered in the article. Conclusions: The history, classification and elements of the art of ornamentation, which were created together with the people over the centuries and became their material and spiritual good were analyzed.Introducción: Hoy en día, un estudio exhaustivo de la artesanía kazaja es de gran importancia tanto para la ciencia como para la experiencia de vida. En el tercer milenio, la autoidentificación de los pueblos del mundo alcanzó un nuevo nivel de investigación. Los bienes nacionales no son sólo monumentos, sino que aparecen como objetos de investigación a través de diversos espectros de percepción científica. El propósito de nuestro artículo es estudiar la representación lingüística de la cosmovisión kazaja en el ornamento nacional. Materiales y Métodos: Junto con los métodos de acumulación y diferenciación, en el trabajo de investigación se utilizan los métodos de análisis histórico comparativo. Resultados y Discusión: En el artículo se considera el problema de reflejar la imagen lingüística del mundo en el ornamento nacional, que es un rico patrimonio de las personas, un símbolo de su cultura, un ejemplo de las obras de los maestros. Conclusiones: Se analizó la historia, clasificación y elementos del arte de la ornamentación, que fueron creados junto con el pueblo a lo largo de los siglos y se convirtieron en su bien material y espiritual

Nonlinear Stochastic Biasing of Peaks and Halos: Scale-Dependence, Time-Evolution, and Redshift-Space Distortion from Cosmological N-body Simulations

We quantify the degree of nonlinearity and stochasticity of the clustering of biased objects, using cosmological N-body simulations. Adopting the peaks and the halos as representative biasing models, we focus on the two-point correlation of the biased objects, dark matter and their cross-correlation. Especially, we take account of the effect of redshift-space distortion and attempt to clarify the scale-dependence and the time-dependence by analyzing the biasing factor and the cross-correlation factor. On small scales, stochasticity and nonlinearity become appreciable and strongly object-dependent, especially in redshift space due to the pair-wise velocity dispersion of the biased objects. Nevertheless, an approximation of deterministic linear biasing $\delta_{\rm obj}\simeq b_{\rm obj} \delta_{\rm mass}$ works reasonably well even in the quasi-linear regime $r > 10 h^{-1}$ Mpc, and linear redshift-space distortion explains the clustering amplitudes in redshift space in this regime.Comment: 17 pages, 9 figures, accepted for publication in PAS

Redshift distortions in one-dimensional power spectra

We present a model for one-dimensional (1D) matter power spectra in redshift space as estimated from data provided along individual lines of sight. We derive analytic expressions for these power spectra in the linear and nonlinear regimes, focusing on redshift distortions arising from peculiar velocities. In the linear regime, redshift distortions enhance the 1D power spectra only on small scales, and do not affect the power on large scales. This is in contrast to the effect of distortions on three-dimensional (3D) power spectra estimated from data in 3D space, where the enhancement is independent of scale. For CDM cosmologies, the 1D power spectra in redshift and real space are similar for wavenumbers $q<0.1h/Mpc$ where both have a spectral index close to unity, independent of the details of the 3D power spectrum. Nonlinear corrections drive the 1D power spectrum in redshift space into a nearly universal shape over scale $q<10h/Mpc$, and suppress the power on small scales as a result of the strong velocity shear and random motions. The redshift space, 1D power spectrum is mostly sensitive to the amplitude of the initial density perturbations. Our results are useful in particular for power spectra computed from the SDSS quasars sample.Comment: MNRAS in press. matches published versio

Acute Kidney Injury in Patients with COVID – 19 Infection: Α Tertiary Referral Hospital Experience

The emersion of the new coronavirus SARS COV 2 (Severe Acute Respiratory SyndromeCoronavirus 2) was rapidly characterized as a pandemic by WHO. The majormanifestation of the virus is respiratory distress; however, the involvement of other organsshould not be overlooked. The kidney is one of the most important target organsof the specific virus with acute kidney injury (AKI) described in 5-36% of COVIDpositive patients and an average 25% within the severely ill.Purp ose: The purpose of this study was to consider the incidence of AKI in patientswith COVID 19 in our cohort and to better understand risk factors associated withAKI. Further, we wanted to investigate the impact of AKI on survival and in hospitalmortality.Methods: Patients admitted to Evagelismos General Hospital with confirmed COVID-19 infection from 11th March until 22th May were investigated. Patients 18 yearsold as well as transplanted patients were excluded from this study. AKI was definedaccording to the AKI criteria.Results : From 99 patients with COVID-19 infection, AKI occurred in 41 (41.4%).A total of 44 patients (44.4%) were admitted to Intensive Care Unit (ICU) and 31 ofthem (70.5%) developed AKI. Of the 44 patients with AKI, 16 (39%) required renalreplacement therapy. Hospital mortality, in total, was 16.2% (37% among patientswith AKI versus 0.02% among those without AKI, p=0.000).Conclusion: AKI was common among patients hospitalized with COVID 19. AKIwas associated with older age, clinical severity and existing CKD