The study of continuum sky background spectrum at low radio frequencies has achieved specific importance in present day observational cosmology . At these low frequencies the sky continuum is contributed by the extragalactic radio sources together with the synchrotron emission of the Milky Way as well as CMB. Following the recombination, the energy exchange between the primordial neutral hydrogen and CMB photons, during its propagation through the ”Dark ages” as well as the ”cosmic dawn” resulted in absorption and emission features in CMB spectrum which evolved with the evolution of the HI over cosmic time. Due to cosmological expansion of the Universe such spectral signatures of cosmological origin is now redshifted to low radio wavelengths. Although the peak to peak amplitudes of the same are smaller by orders of magnitude than the total galactic and extragalactic contribution at these frequencies the later is expected to be smooth over the scales of few hundred MHz. Hence, except for the extreme cases where the time scale over which such radiative transfer interaction occurred is very long and therefore the spectral fluctuations are spread over a large range of frequencies, these cosmological radiation signatures should be detectable at meter wavelengths. The duration and frequency at which such spectral signatures may occur can give constraints on the physical processes that governed the process of such energy exchange at a very early time, the history of evolution of the gas and the nature and evolution of sources of first light in the Universe. Measurements of the absolute brightness of the continuum background at meter wavelengths and detection of the spatial and spectral variations can therefore be an important probe of cosmology. In addition, measurements to date suggest that the radio background that is of extragalactic origin consists of CMB plus a power-law spectrum and has a brightness temperature of (1.2 ± 0.09) × (ν/1 GHz)−2.60±0.04 K. Surprisingly, the sky brightness corresponding to discrete radio sources detected in the deepest surveys to date account for only a fraction of the extragalactic radio background, even after excluding the CMB. Improved measurements of the radio background and, in particular, the spectrum at long wavelengths where errors are relatively larger, are important in estimating the spectrum of the unexplained part and thereby constraining the sources of this cosmic radiation. The wideband measurements at meter wavelengths pose limit on the accuracy of such measurements where the errors are relatively large. The instrument systematics, which are frequency dependent, in interaction with the sky signal may result in an incorrect estimate of the absolute sky brightness as well as may give rise to spectral features which may confuse with the true cosmological signatures in the foreground. A strategic system design with the aim of minimizing the systematics and characterization of the system non-ideal behavior can lead to the measurement accuracy with which the cosmological signatures could be detected along with the absolute measurement of the foreground. The aim of the work that constitute this thesis is precision measurement of the continuum radio emission at long wavelengths and detect the signature from the epoch of reionization in the background spectrum. A single element radio telescope system has been designed and built which is capable of useful measurement of spectral signatures of the EoR in the radio background. SARAS deployed in the Gauribidanur Observatory, about 80 km north of Bangalore in India. The design, calibration method and observation strategies developed are novel and unique, and relevant for any wideband measurements. The content of this thesis is outlined below. The Chapter 1 briefly introduces to the 21 cm cosmology. The neutral hydrogen as an cosmological probe is discussed first. The redshifted 21 cm signal and its possible use to probe the early Universe is discussed in detail. The chapter also gives a description of the redshifted 21 cm background and the EoR global signature as well as the 21 cm power spectrum. Finally an account of the recent and future experiments for detection of the global EoR signature and the EoR power spectrum are given. In the light of the science introduced in this chapter, the major aim and the work of the thesis is also summarised. In Chapter 2 the design philosophy of the SARAS spectrometer is illustrated. The basic elements of the system, the antenna, analog and the digital receiver have been described in detail. The complete configuration and the complex performance of the integrated system are detailed. For an ideal performance of such a wideband system the calibration strategies are considered and measurement equations are derived. Chapter3 addresses the most important issues of systematic effect for this wideband continuum measurement. The designed system performance deviates from its ideal due to non-idealities. The non-ideal behaviour of the real systems that are the limiting factors for a precision wideband measurement at low frequencies are thoroughly investigated. The effects of single and multiple reflections that occurs due to impedance mismatch internal to the system and results in spurious response in the measured data are considered. Within the limits of the known systematics, the system has been argued to qualify to be able to measure the EoR spectral signature in the background spectrum. Chapter 4 gives the details of the SARAS observation and description of the measurement that has been done by the SARAS spectrometer from the Gouribidanur Radio Observatory . The detailed understanding of the systematics led to the two strategic observation modes; EoR mode and RB mode, which are also discussed in this chapter. Next, the absolute calibration of the SARAS spectrometer is described following which the interference rejection algorithms, purpose developed for rejection of RFI from the SARAS data are outlined. The measured data is calibrated and the additional calibration product is derived. The data set is then modelled by modelling the sky noise and the systematic effects. In Chapter 5 the methodology of the SARAS data analysis is illustrated along with step by step analysis of the observation made in the RB mode. The model that is derived in chapter 4 is fitted to the measurements and the parameters are estimated by minimising the merit function Chi-square. The minimisation followed the downhill simplex algorithm which is outlined in this chapter. The data analysis strategy relied on the derivation of the initial values of the parameters from the measured data. The data has been fitted in hierarchy and initial guesses for subset of parameters are derived from each step of hierarchical modelling. This method of analysis is strategic and discussed in detail in this chapter. The statistical and systematic error of measurement are discussed next. Finally, the posterior probability distribution of the parameters are calculated by uniformly sampling the parameter space around the best fit values and calculating the Chi-square and the likelihood functions of the parameters. Mariginalizing the computed posterior probability distribution over the system parameters, the error on estimated sky parameter or the confidence region of the sky parameter is estimated. Chapter 6 presents the analysis identical to that presented in the Chapter 5 for the data acquired in the second observing mode, the EoR mode is presented. In this section the detection ability and the limitations of the SARAS observations, made from the Gouribidanur Radio observatory, for a useful detection of the EoR spectral signature is considered. Chapter 7 described a concept of system bandpass calibration using the time domain information that could be obtained from the voltage samples before computing the power spectrum. In the Chapter 3, the spurious periodic correlation, generated due to the internal reflections of the noise voltages is discussed in detail. If a short pulse is injected into the system via the antenna, due to internal reflections, the primary pulse in the output voltage samples would be followed by a series of delayed pulses each of which is generated by subsequent reflections internal to the system. Inspection of such pulses in the time domain could potentially provide with accurate bandpass calibration. A digital hardware is programmed and a nano second pulse generator-accumulator system is built. The performance of this system and table top demonstration of this bandpass calibration concept is presented in this chapter. This pulse injection system is used in a proposed calibration experiment in the Parkes radio telescope. The initial result of the experiment is presented in this chapter. In Chapter 8 the work carried out for this thesis is summarised. The end to end task of carrying out the background measurement by purpose building a single element radio telescope, observing with it and analysis of the data has led to a successful measurement of the background spectrum with an accuracy > 1%. The detailed understanding of the problems associated with the precision measurements and development of the measurement techniques that can overcome such problems has led to significant progress towards a successful detection of the EoR signatures. Some aspects and ideas which are understood to be essentials for such an experiment yet unexplored here due to limited time are listed in this section and the future prospcts of this work is also discussed.

This study investigates the kanji learning strategies used by learners of Japanese from two non-logographic orthographic backgrounds within the Sinosphere (Korean and Vietnamese), and alphabetic-language-based backgrounds, and how the three groups compare to each other. The study utilised data analysis techniques on data collected from 40 Japanese language learners via an online survey, and semi-structured interviews with four learners from Korea and Vietnam. The study found that Korean and Vietnamese learners benefit from first language kanji knowledge when learning to recognise Japanese kanji (particularly among Korean learners), and that common and preferred kanji learning methods differ between groups, with learners of alphabet-language backgrounds preferring methods from the planning learning and evaluating learning metacognitive strategies categories; and Korean and Vietnamese learners preferring association cognitive and planning learning metacognitive methods.

This study focuses on connection between socioeconomic factors and the didactic choices in the English language teaching in lower primary school. The aim of the study is to examine if and how these choices differ between a charity-based school and a non-charity based (private) school in a slum area in Kenya, based on the reflections of teachers. Furthermore the aim is to investigate the motives or reasons behind the didactic choices, as expressed by the teachers during the interviews, and how these are possible to relate to the economic and social situation of the schools and the children. The research questions for the study was what the similarities and the differences are in how the lower primary teachers in an informal school compared with a private school in a rural area in Kenya reflect on their didactic approach in the subject English. The second question is how their reflections and didactic choices can be understood in relation to the economic and social conditions that characterize each school. The method used was a qualitative multi case study where the data collection was made by direct observations of four lessons and semi-structured interviews with four teachers, two in each school. The theoretical perspective used was Maslow’s motivation theory about the hierarchy of basic needs (1970, 1987) and the frame factor theory through Löwing (2004) and Knutas (2008). The main findings were that despite the two schools different economical resources and the childrens’ different socioeconomic backgrounds the overall didactic approach was very similar which partly can be explained with social and cultural norms that affect the way of teaching. Another finding was that the biggest obstacle for the language learning was small amount of pre-knowledge which was connected to poor or no use of English at home, and a lack of basic need. These factors were according to the teachers mostly found among the poor or in some way vulnerable children

The dissertation examines the use of background appeals in campaign messages. I argue that background appeals allow campaigns to meet two seemingly conflicting incentives in the same message—the incentive to reduce voters’ uncertainty about their candidate, and the incentive to remain ambiguous in their issue positions. Background appeals allow voters to know more about a candidate and develop more certainty about what he will do in office. At the same times, campaigns can achieve this goal while avoiding specific policy commitments, which, on controversial issues, might repel a significant part of the electorate. I test my argument by examining how campaigns plan on using candidates’ backgrounds by interviewing a sample of political consultants. The consultants I interviewed make the candidate’s background a top priority in developing a message plan for their clients. They want to show voters “who their candidate is” as a means of developing likeability and credibility with voters. As expected, campaigns use background appeals frequently, in nearly 80% of advertisements aired by US Senate campaigns in 2000 and 2002. But in these appeals, campaigns avoid specifically connecting their candidate to particular policies. Also, the appeal of ambiguity is so great that campaigns only use more specific background appeals when discussing the opponent’s background. Background appeals can have a positive effect on perceptions of a candidate. Using an experimental design, I vary the background of a mock candidate for Congress while holding constant his issue position. Respondents regard the candidate more favorably when they learn about his occupation than when they receive no such information. / text

<p>Children from different backgrounds, cultures and home environments attend school everyday. The educational system of today focus on the importance for every individual pupil to take responsibility, in order to gain knowledge. From an early age should the pupils learn how to work independant and take responsibility for their education. My questian, and what I have decided to discuss in this paper, is wether everyone has the same opportunity to gain knowlwdge and learn trough this method. In preperation for this essay I read litterature where the authors claims that this kind of educational system is not for everyone, but it benefits those pupils that comes from a middleclass background.</p><p>So, is our school system fair and equal? Can everyone, no matter what social and cultural group they belong to, get the education thay have right to? In order to get a deeper understanding I interviewed three teachers that works in different schools. The conclusion in this paper is based on these interviews, so it is not to be generalized. The paper has three major hedings; The national curriculum and individual responsibility, those who benefits, how does one help?</p><p>The results of the paper, and the conlclusion of the interviews, shows that it is crucial for the pupils to have been thaught from a very young age, to take responsibility for their own learning. The teachers also agreed that those who benifits from this kind of educational system has supportive parents that value the need of education. This despite which ethnic, social or cultural group they belong to. All pupils must be aware of the curriculum, and the teaching needs to be individualized.</p>

This is a theoretical and empirical study of leadership. Although sociologists have contributed important theories and research on authority and power, there is not yet a developed leadership theory in sociology. On the other hand, leadership studies in other disciplines are not satisfying, and they will not be satisfying in the foreseeable future if they adhere to their basic theoretical orientations, e.g. focusing on leadership personal traits and characteristics. I elaborate the important sociological theories that can be used in the study of leadership. I also intend to link sociological theories of leadership to social background analysis. The social backgrounds considered are family status, education, religion, military service, and more. Particular attention is paid to military background and its impact on business, because military has always been such an important social phenomenon but the theories of it have been controversial.The study of leadership inevitably involves both individuals and their groups. With evidence obtained from different data sources on leaders and on business organizations, I studied the impact of military social background of business leaders. This research unpacks the rise of business leaders with military experience in the late 20th century, using a database on the 20th century Great American Business Leaders. This research also measures the organizational performance of these leaders, incorporating information from Standard & Poor's Compustat database. Statistical techniques like logistic regressions and hierarchical linear models are used in the analysis to test various effects on personal and organizational performance. I found that military experience does not help a business leader in aspects like time taken to become a CEO and time to be a CEO, but it does help organizational performance as measured by profitability. Both rank and number of years in the military contribute to profitability. I also found that ex-military business leaders differ from non-military business leaders in certain organizational behaviors, e.g. they are less likely to downsize the organizations.The theory of institutional logics and social background analysis were combined in this study. I also attempted to link institutional logics with theories of rationality. From the idea of institutional leadership and inter-institutional relationship, I suggested a theory of extended rationality.

No description available.

Simulations and observations of the microwave sky are of great importance for under- standing the Universe that we reside in. Specifically, knowledge of the Cosmic Microwave Background (CMB) and its foregrounds – including the Sunyaev-Zel’dovich (SZ) effect from clusters of galaxies and radio point sources – tell us about the Universe on its very largest scales, and also what the Universe is made of. We describe the creation of software to carry out large numbers of virtual sky simulations. The simulations include the CMB, SZ effect and point sources, and are designed to examine the effects of point sources and the SZ effect on present and recent observations of the CMB. Utilizing sets of 1,000 simulations, we find that the power spectrum resulting from the SZ effect is expected to have a larger standard deviation by a factor of 3 than would be expected from purely Gaussian realizations. It also has a distribution that is significantly skewed towards increased values for the power spectrum, especially when small map sizes are used. The effects of the clustering of galaxy clusters, residual point sources and uncertainties in the gas physics are also investigated, as are the implications for the excess power measured in the CMB power spectrum by the CBI and BIMA experiments. We also investigate the possibility of using the One Centimetre Receiver Array (OCRA) receivers to observe the CMB and measure this high-multipole excess. An automated data reduction package has been created for the OCRA receivers, which has been used in end-to-end simulations for OCRA-p observations of point sources. We find that these simulations are able to realistically simulate the noise present in real observations, and that the introduction of 1/ f noise into the simulations significantly reduces the predicted ability of the instruments to observe weak sources by measuring the sources for long periods of time. The OCRA-p receiver has been used to observe point sources in the Very Small Array fields so that they can be subtracted from observations of the CMB power spectrumWe find that these point sources are split between steep and flat spectrum sources. We have also observed 550 CRATES flat spectrum radio sources, which will be useful for comparison to Planck satellite observations. Finally, the assembly and commissioning of the OCRA-F receiver is outlined. This receiver is now installed on the Torun ́ 32-m telescope, and is currently being calibrated prior to starting observations in the next few months.

This thesis shows how the appeal to the transcendent characterizes aspects of the debate amongst leading contemporary philosophers of science regarding the value-free ideal and the attendant aim of attaining objective knowledge. It compares the positions of leading feminist philosophers of science (Longino and Harding) with influential figures in the historically rooted Western belief who appeal to the transcendent in the pursuit of knowledge of the necessary and of the contingent. Chapter 2 relates the historically rooted Western belief in appeal to the transcendent in the pursuit of knowledge and includes two components: the pursuit of knowledge of the necessary and knowledge of the contingent. Chapter 3 assesses how contemporary leading feminist philosophers of science have contended with beliefs of influential 20th century thinkers (Weber, Kuhn and Quine) regarding this problem. Through this comparison, I provide commentary on how current leading philosophers of science have addressed the value-free ideal issue through the prism of appeal to transcendent reason as justification, as opposed to the historically rooted appeal to the transcendent itself via reason as justification and how this apparent disparity has bearing on the debate concerning the value-free ideal and the attendant goal of achieving objective knowledge. / Graduate / 0727 / jahn712002@yahoo.ca

In this thesis I construct various models to interpret measurements of the clustering of dusty star-forming galaxies through the angular power spectrum statistic. The goals of this work are, firstly, to facilitate the separation of the dusty galaxy contribution from the cosmic microwave background background (CMB) power spectrum, and, secondly, to improve our understanding of the physical properties of these galaxies. I present analysis of the first cross-correlation of millimeter and submillimeter sky maps, using data from the Atacama Cosmology Telescope (ACT) and the Balloon-borne Large-Aperture Submillimeter Telescope (BLAST), which revealed that the dusty galaxies that dominate the submillimeter sky are, to a significant extent, those same sources that are a nuisance contaminant for CMB cosmology. I then perform a joint fit to the ACT and BLAST power spectra as well as early results from the Planck Surveyor to construct a simple phenomenological template for the frequency and angular scale dependence of the contribution from clustered dusty galaxies to the total power spectrum. This template may be used to assist in extracting the CMB signal from future ACT and other data sets. The correlation between dusty galaxies and the thermal Sunyaev Zel'dovich effect leads to an additional contribution to the measured angular power spectrum that further hampers constraining quantities of cosmological interest. I present the first physically-motivated model for this correlation, and make predictions for its frequency and scale dependence as a CMB foreground. Finally, I combine angular power spectrum measurements from ACT, Planck and other instruments with deep far-infrared and submillimeter source number counts and constrain a model for the emission properties of these dusty galaxies. I demonstrate that the power spectrum carries significant constraining power and can improve our understanding of dust emission and star formation from unresolved objects at high redshift.