The cosmic microwave background bispectrum from the non-linear evolution of the cosmological perturbations

This article presents the first computation of the complete bispectrum of the cosmic microwave background temperature anisotropies arising from the evolution of all cosmic fluids up to second order, including neutrinos. Gravitational couplings, electron density fluctuations and the second order Boltzmann equation are fully taken into account. Comparison to limiting cases that appeared previously in the literature are provided. These are regimes for which analytical insights can be given. The final results are expressed in terms of equivalent fNL for different configurations. It is found that for moments up to lmax=2000, the signal generated by non-linear effects is equivalent to fNL~5 for both local-type and equilateral-type primordial non-Gaussianity.Comment: 44 pages, 8 figure

CMB spectra and bispectra calculations: making the flat-sky approximation rigorous

This article constructs flat-sky approximations in a controlled way in the context of the cosmic microwave background observations for the computation of both spectra and bispectra. For angular spectra, it is explicitly shown that there exists a whole family of flat-sky approximations of similar accuracy for which the expression and amplitude of next to leading order terms can be explicitly computed. It is noted that in this context two limiting cases can be encountered for which the expressions can be further simplified. They correspond to cases where either the sources are localized in a narrow region (thin-shell approximation) or are slowly varying over a large distance (which leads to the so-called Limber approximation). Applying this to the calculation of the spectra it is shown that, as long as the late integrated Sachs-Wolfe contribution is neglected, the flat-sky approximation at leading order is accurate at 1% level for any multipole. Generalization of this construction scheme to the bispectra led to the introduction of an alternative description of the bispectra for which the flat-sky approximation is well controlled. This is not the case for the usual description of the bispectrum in terms of reduced bispectrum for which a flat-sky approximation is proposed but the next-to-leading order terms of which remain obscure.Comment: 20 pages, 12 figure

Cosmic microwave background bispectrum on small angular scales

This article investigates the non-linear evolution of cosmological perturbations on sub-Hubble scales in order to evaluate the unavoidable deviations from Gaussianity that arise from the non-linear dynamics. It shows that the dominant contribution to modes coupling in the cosmic microwave background temperature anisotropies on small angular scales is driven by the sub-Hubble non-linear evolution of the dark matter component. The perturbation equations, involving in particular the first moments of the Boltzmann equation for the photons, are integrated up to second order in perturbations. An analytical analysis of the solutions gives a physical understanding of the result as well as an estimation of its order of magnitude. This allows to quantify the expected deviation from Gaussianity of the cosmic microwave background temperature anisotropy and, in particular, to compute its bispectrum on small angular scales. Restricting to equilateral configurations, we show that the non-linear evolution accounts for a contribution that would be equivalent to a constant primordial non-Gaussianity of order fNL~25 on scales ranging approximately from l~1000 to l~3000.Comment: 21 pages, replaced to match published versio

Alienation in Capitalist Society

This paper attempts to study the roots of the alienation that currently exists in society. Alienation for this paper refers to the rift that exists between humans as we currently are and the potential that we can reach. This paper will attempt to trace the roots of alienation to the origins of the capitalist mode of production. In this, it will first deal with the "transition debate" and posit an understanding of the transition as something that brought about a drastic and qualitative change in social relations and the ways in which people reproduce themselves. It will attempt to denaturalize capitalist relations in order to truly trace the origins of the logic of capital. The paper will then delve into human nature. It will put forth a notion of human nature that is social and productive in order to understand some of the ways that capitalist production relations have fettered the growth of human nature. Finally, the paper will deal with alienation. It will trace the roots of alienation in some of the foundational tenets of the capitalist mode of production and discuss ways in which this alienation manifests itself. This paper ends with noting that alienation is inherent within capitalism and that in order for humans to achieve the same potential that capitalist production also generates, capitalism itself will have to be replaced with an alternate mode of production

Diagnostic in CVD processes by IR pyrometry

The control of CVD processes requires in situ analysis techniques and real time monitoring to identify the chemical species involved in the mechanism, to determine the growth kinetics and more generally to detect and analyze the dynamics of any event occurring during the growth of the film. We demonstrate through four representative examples that IR pyrometry allows to answer to the last two items, which make it an attractive diagnostic tool for CVD processes, simple to use, sensitive at nanometric scale, economic and being able to operate either under atmospheric or low pressure. Thus, we monitored the initial stages of the growth of conducting diffusion barriers CrCxNy on Si and as a second example, we have followed their heat treatment to detect possible phase transformations. The case of MOCVD of Fe reveals the high sensitivity of this diagnostic technique. Indeed, the abrupt changes of the pyrometric signal correlate remarkably to changes in the growth mode. Lastly, the characteristic oscillations due to multireflexions at the interfaces observed in the first stages of the growth of transparent TiO2 film allow the real time determination of the growth rate. These examples show the great diagnostic potentialities of IR pyrometry for the optimization and the control of CVD processes

Embedded layer of Ag nanoparticles prepared by a combined PECVD/PVD process producing SiOxCy-Ag nanocomposite thin films.

Structural properties of SiOxCy–Ag nanocomposite thin films prepared by a dual process PVD–PECVD in the same reactor have been investigated. The experimental results have demonstrated the influence of a PECVD process carried out at room temperature for the growth of a dielectric matrix on the size and the distribution density of Ag nanoparticles (NPs) deposited beforehand by magnetron sputtering. The plasma during the growth of the encapsulation SiOxCy layer caused a diffusion of silver from NPs through the SiOxCy matrix associated with a decrease in the average size of nanoparticles and an increase of their distribution density. Silver diffusion is blocked at a barrier interface to form a buried layer of individual Ag NPs which, for instance, can find plasmonic applications. Silver also diffuses toward the outer surface inducing antibacterial properties. In both cases initial Ag NPs act as reservoirs for multifunctional properties of advanced nanostructured films

The importance of management training in the hotel industry

M.Comm. (Strategic Management)The South African hotel industry is a labour intensive industry, with high staff turnover and a shortage of skilled labour. The introduction of the national grading system and an increase in tourists, both local and foreign, placed more pressure on hotels to improve the quality of their services. Improvement of quality service is linked to well qualified personnel. The question : ''Does the countryhavethe requiredlabourforce" thus arises. The answer is obviously "No'~ In order to solve the above mentioned labour problem, management training and management development programmes are of cardinal importance. Top management in hotels must show more interest inand commitment towards management training and development. Training at colleges, technikons and universities is placed under the microscope to ascertain whether it meets the requirements of the industry. Most students have the necessary theoretical training, but practical training (in-service training) has to be improved.Affirmative action is implemented to satisfy the needs of the majority in the work force. The necessity of affirmative action and its implementation is investigated with the aim of affording the majority of the labour force the opportunity to be trained. The main aim of this study is to highlight the necessity of management training in a changing environment. It is important that hotel management identify these changes and take action accordingly in order to remain competitive

MOCVD of Cr3(C,N)2 and CrSixCy Films Growth and Characterization

CrCxNy and CrSixCy thin films were deposited under low pressure by metallorganic chemical vapor deposition (MOCVD) in the temperature ranges 380-450°C and 450-500°C, respectively, using Cr(NEt2)4 and CrCH2SiMe34 as single-source precursors.The growth was achieved in a cold-wall vertical reactor using, respectively, H2 and He as the carrier gases. Both types of films exhibit a mirrorlike surface morphology and are amorphous asdeposited. The CrCxNy layers start to crystallize at 600°C after annealing for 1 h under vacuum,whereas it is necessary to reach 650°C under H2 atmosphere. In both cases, the original ternary phase Cr3(C0.8N0.2)2 crystallizes. The resistivity of as-deposited amorphous CrCxNy films is typically 600. cm, and it decreases to 150 #. cm after annealing upon the formation of polycrystalline Cr3#C,N#2 films. The CrSixCy layers have a very stable amorphous structure until 850°C for 4 h. In spite of their metallic appearance, they exhibit a high resistivity compared to the Cr3#C,N#2 films. The main characteristics of these Cr-based layers is presented and discussed

Determinants of House Ownership Among University of Uyo Staff: Emerging Lessons

Man has consistently tried to build his immediate environment so as to provide a means to cover and protect himself from the external elements. Despite man’s effort to provide decent accommodation, his effort seems unrealizable with processes that are too cumbersome. This paper seeks to investigate determinants of house ownership among University of Uyo Staff. For the purpose of collecting data, a population size of 2494 Staff was identified through the Department of Establishment, University of Uyo. However, one hundred and fifty (150) copies of questionnaire were distributed among the University staff using simple random technique. A Factor Analysis technique was used to analyze fourteen factors which five components were extracted and their factor loadings were used in examining the determinants. The factors were renamed to include family life cycle, identity, cost saving resources, socioeconomic, and catalyst of determination. Conclusion were reached that some individuals are oblivious or lack determination to build their own houses or they await a time where considerable savings will propel them to build a house but such opportunities are scanty. The study recommended that Physical Planners and Planning Agencies should advice government on the technological innovation needed to be in place to facilitate housing development which are not limited to computerized land information system, Geographic Information System and other relevant tools that can aid efficiency of work in the agencies. Also, people should invest in real estate knowing that housing is a veritable item of economic investment. Keywords: House, Determinants, University of Uyo Staff, Ownership

Ubuntu and skills development in the Overberg region of the Western Cape

The philosophy of Ubuntu forms an integral part of tourism and tourism development in underdeveloped and neglected regions in South Africa. The Overberg region in the Western Cape is a classic example of where this philosophy can be applied for the benefit of the entire region. It is high time that the tourist ‘rand’ be extended to the local communities to empower them in a real and significant manner. The untapped secrets of the Overberg were revealed and identified in a very recent study of the region. The Overberg is situated between Cape Town central and the Garden Route, and because the access route is between Caledon and Swellendam, the area tends to be ignored, whereas Cape Town with its popular branding and abundant tourist offerings attracts many international tourists annually. The Western Cape is divided into ten different regions, each with its own unique characteristics and appeal, of which the Overberg is the third biggest in terms of its geographical area. This unspoilt area boasts some of the region’s richest birdlife and a wealth of fauna and flora; the southernmost tip of Africa, where the cold Atlantic and warm Indian oceans meet; sprawling, white, sandy beaches and dunes; an abundance of whales and last, but not least, it has the greatest historical and cultural significance of all the regions. Given that Cape Town is the gateway to the entire region and benefits from the strong Mother City brand, the Overberg should also be branded and marketed strongly to expose the ‘untapped secrets’ of the region. If this became a regional priority of Cape Town Routes Unlimited (DMO), the Overberg would enjoy the benefit of better tourism, which would stimulate greater skills development for the owners and employees of the region’s tourism Small, Medium and Micro Enterprises (SMMEs). Standing together, building the brand together and promoting the essence of real empowerment in the region can only lead to more sustainable tourism enterprises. The biggest challenge however, is the level of skills, expertise and product knowledge of the current operators in the Overberg region. Equipping the people of this region with skills, determination and passion will inevitably lead to the highest standard of satisfaction in terms of the unlimited needs of tourists. Ubuntu, the way forward.http://cenled.co.za/skillswork-theory-and-practice-journal/am201