Simulations and Observations of the Microwave Universe

[Abridged] Simulations and observations of the microwave sky are of great importance for understanding the Universe that we reside in. Specifically, knowledge of the CMB and its foregrounds - including the 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, and is significantly skewed towards increased values for the power spectrum. 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. We carry out end-to-end simulations for OCRA-p observations of point sources. The introduction of simulated 1/ f noise 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 VSA fields so that they can be subtracted from observations of the CMB power spectrum. We 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. [Abridged]Comment: 289 pages. This thesis was submitted by Michael Peel to The University of Manchester for the degree of Doctor of Philosophy in the Faculty of Engineering and Physical Sciences on the 18th December 200

Addressing unobserved selection bias in accounting studies: the bias minimization method

This note explains the minimum-biased estimator (MBE), which accounting researchers can use to analyze the robustness of regression or propensity score-matched treatment estimates to unobserved selection (endogeneity) bias. Based on the principles of the Heckman treatment model, the MBE entails estimating matched treatment effects within a range of propensity scores that minimizes unobserved selection bias. A major advantage of the MBE is that an instrumental variable is not required. The potential utility of the MBE in accounting studies is highlighted, and a familiar empirical illustration is provided

Identification And Functional Characterization Of Novel Determinants Of The Somatotropes And Lactotrope Lineages In The Anterior Pituitary

The differentiation of the hormone-producing cell lineages of the anterior pituitary represents an informative model of mammalian cell fate determination. The generation and maintenance of two of these lineages, the growth hormone (GH) producing somatotropes and the prolactin (PRL) producing lactotropes, are dependent on the pituitary-specific transcription factor, POU1F1. While POU1F1 is expressed in both cell types, and plays a direct role in the activation of both the Gh and Prl genes, GH expression is restricted to somatotropes and PRL expression is restricted to lactotropes. These observations imply the existence of additional, cell type-enriched factors, that contribute to the somatotrope and lactotrope cell identities. Here, we use transgenic mouse models to facilitate sorting of somatotrope and lactotrope populations based on the expression of fluorescent markers expressed under Gh and Prl gene transcriptional controls. The transcriptomic analyses reveal a concordance of gene expression profiles in the two populations. The limited number of mRNAs that are selectively enriched in each of the two populations includes a set of transcription factors. A subset of these factors may have roles in pituitary lineage divergence, and/or in regulating expression of cell-type specific genes after differentiation. Four of these factors were validated for lineage enrichment at the level of protein expression, two somatotrope-enriched and two lactotrope-enriched. Three of these four factors were shown to have corresponding activities in appropriate enhancement or repression of landmark somatotrope or lactotrope genes in a pituitary-derived cell culture model system. Conditional inactivation of the genes encoding these factors in mice revealed that two of these transcription factors impact the expression of landmark hormone genes and alter cell phenotypes in primary murine pituitary. Subsequent mechanistic studies revealed that these two factors act on their target genes either through a direct binding at the target promoter and release of paused Pol II complexes, or through indirect mechanism(s). The functions of these two factors are further remarkable in how they maintain hormone expression in the lactotrope and somatotrope lineages; one serves to enhance landmark Prl gene expression in lactotropes while the second serves to reciprocally repress expression of the Prl gene in somatotropes. In conclusion, these studies identify novel regulators of the somatotropes and lactotropes, explore their mechanisms of action, and establish a useful database for further study of these lineages in the anterior pituitary

The impact of filing micro-entity accounts and the disclosure of reporting accountants on credit scores: an exploratory study

There is a dearth of evidence regarding the potential costs incurred by small private companies that opt to publish only an unaudited abbreviated balance sheet. This paper provides new evidence regarding whether UK companies that publish reduced balance sheet information in micro-entity annual accounts are allocated lower credit scores by a credit rating agency. Recently, for the smallest companies, a new exemption category for ‘micro-entities’ was introduced. Qualifying companies may elect to file even less unaudited balance sheet information than their small company counterparts. Consistent with the conjecture that publishing micro accounts conveys a negative signal to the credit scorer, there is systematic evidence that micro-entities are assigned worse credit scores. This result is robust to the employment of statistical methods that account for observed and unobserved bias. Based on both assurance and signalling tenets, the second novel conjecture examined in this study, is that companies which disclose their annual accounts are prepared by an accountancy firm (reporting accountant) will attract higher credit scores. Contrary to extant research which reports that companies that opt for voluntary audits receive higher credit scores, there is no evidence that the credit scorer rewards companies whose accounts bear the imprimatur of a reporting accountant

Compression failure of angle-ply laminates

The present work deals with modes and mechanisms of failure in compression of angle-ply laminates. Experimental results were obtained from 42 angle-ply IM7/8551-7a specimens with a lay-up of ((plus or minus theta)/(plus or minus theta)) sub 6s where theta, the off-axis angle, ranged from 0 degrees to 90 degrees. The results showed four failure modes, these modes being a function of off-axis angle. Failure modes include fiber compression, inplane transverse tension, inplane shear, and inplane transverse compression. Excessive interlaminar shear strain was also considered as an important mode of failure. At low off-axis angles, experimentally observed values were considerably lower than published strengths. It was determined that laminate imperfections in the form of layer waviness could be a major factor in reducing compression strength. Previously developed linear buckling and geometrically nonlinear theories were used, with modifications and enhancements, to examine the influence of layer waviness on compression response. The wavy layer is described by a wave amplitude and a wave length. Linear elastic stress-strain response is assumed. The geometrically nonlinear theory, in conjunction with the maximum stress failure criterion, was used to predict compression failure and failure modes for the angle-ply laminates. A range of wave length and amplitudes were used. It was found that for 0 less than or equal to theta less than or equal to 15 degrees failure was most likely due to fiber compression. For 15 degrees less than theta less than or equal to 35 degrees, failure was most likely due to inplane transverse tension. For 35 degrees less than theta less than or equal to 70 degrees, failure was most likely due to inplane shear. For theta less than 70 degrees, failure was most likely due to inplane transverse compression. The fiber compression and transverse tension failure modes depended more heavily on wave length than on wave amplitude. Thus using a single parameter, such as a ratio of wave amplitude to wave length, to describe waviness in a laminate would be inaccurate. Throughout, results for AS4/3502, studied previously, are included for comparison. At low off-axis angles, the AS4/3502 material system was found to be less sensitive to layer waviness than IM7/8551-7a. Analytical predictions were also obtained for laminates with waviness in only some of the layers. For this type of waviness, laminate compression strength could also be considered a function of which layers in the laminate were wavy, and where those wavy layers were. Overall, the geometrically nonlinear model correlates well with experimental results

Towards a framework for cooperation:spatial public diplomacy on the island of Ireland

European spatial planning arguments advocate a blend of strategic thinking, coordination and related initiatives to promote and secure territorial cohesion. These ambitions embrace a set of normative agendas around economic, social and environmental convergence, competitiveness, policy coordination and efficient infrastructure provision across space. In practice, territorial management then involves devising interventions across inter-connecting scales of governance which comprise complex agency relations, differentiated places and defined communities. In transnational contexts, attempts to foster appropriate spatial governance arrangements and relations across sovereign borders necessitate re-crafting planning and development cultures and service delivery practices to advance territorial cohesion. Transnational working necessarily involves cooperation across an extended range of institutions, interests, influences and potential actors. This paper examines attempts to secure bi-lateral commitment to a joint planning framework for the two distinct territories on the island of Ireland. Specifically, it traces the formal and informal activities involved in the development of the 2013 Framework for Cooperation between the Republic of Ireland and Northern Ireland. Informed by ideas of cross-border regionalism, it discusses the necessary spatial public diplomacy involved in the social reconstruction of strategic spatial planning to improve policy coordination and cross-border working

The timeliness of UK private company financial reporting:Regulatory and economic influences

This paper investigates the extent to which the timeliness of UK private companies’ accounting information reflects regulatory and economic influences by studying the impact of a one month shortening of the statutory regulatory filing deadline. Using the financial reporting lag and propensity to file late as measures of timeliness, we find that although reporting behaviour is largely driven by regulatory deadlines, companies conjectured to be producing accounting information for reporting to outside investors publish their accounts significantly more quickly, and are substantially less likely to file beyond the statutory deadline (late), than their counterparts lacking similar incentives. However, in terms of this reporting lag differential, the change in regulation had a homogeneous impact. We report a significant reduction in the mean and median filing time, but an increase of 46% in the proportion of firms filing late, in the year following the regulatory change. Our results are robust to the employment of a number of different estimation methods, including matching and Huber and median regressio

Foreword

Early Middle Cambrian bituminous coquinoid limestones from a tectonically isolated outcrop in southwestern Kyrgyzstan yield a remarkably diverse fauna, with stem-group cnidarians, trilobites, rhynchonelliformean brachiopods, and other shelly fossils. The fossil site is in the northern foothills of the Turkestan Range and thus forms part of the westernmost extension of the South Tien Shan. The fauna includes two fairly well known trilobite species, Glabrella ventrosa Lermontova, 1940 and Dorypyge richthofeniformis Lermontova, 1940, that provide confident support for an Amgan age of the rocks. New described taxa include the stem-group cnidarian Cambroctoconus kyrgyzstanicus Peel sp. nov., the trilobite Olenoides sagittatus Geyer sp. nov., and the helcionelloid Manasoconus bifrons Peel gen. et sp. nov. Additional fossils within the samples include the trilobites Olenoides sp. A, Kootenia sp., and Pseudoeteraspis? sp.; the rhynchonelliform brachiopods Narynella cf. ferganensis (Andreeva, 1962), Narynella? sp., Austrohedra? sp. nov., and two species of uncertain generic affinity; the tommotiid Tesella sp.; the hyolithelminth Hyolithellus sp.; and the palaeoscolecid Hadimopanella oezgueli Gedik, 1977. Of particular interest is Cambroctoconus kyrgyzstanicus with an octagonal corallum and a sparsely septate calyx

Hierarchical community structure in networks

Modular and hierarchical structures are pervasive in real-world complex systems. A great deal of effort has gone into trying to detect and study these structures. Important theoretical advances in the detection of modular, or "community", structures have included identifying fundamental limits of detectability by formally defining community structure using probabilistic generative models. Detecting hierarchical community structure introduces additional challenges alongside those inherited from community detection. Here we present a theoretical study on hierarchical community structure in networks, which has thus far not received the same rigorous attention. We address the following questions: 1)~How should we define a valid hierarchy of communities? 2)~How should we determine if a hierarchical structure exists in a network? and 3)~how can we detect hierarchical structure efficiently? We approach these questions by introducing a definition of hierarchy based on the concept of stochastic externally equitable partitions and their relation to probabilistic models, such as the popular stochastic block model. We enumerate the challenges involved in detecting hierarchies and, by studying the spectral properties of hierarchical structure, present an efficient and principled method for detecting them.Comment: 22 pages, 12 figure