Evidence for Thermally Activated Spontaneous Fluxoid Formation in Superconducting Thin-Film Rings

We have observed spontaneous fluxoid generation in thin-film rings of the amorphous superconductor Mo$_3$Si, cooled through the normal-superconducting transition, as a function of quench rate and externally applied magnetic field, using a variable sample temperature scanning SQUID microscope. Our results can be explained using a model of freezout of thermally activated fluxoids, mediated by the transport of bulk vortices across the ring walls. This mechanism is complementary to a mechanism proposed by Kibble and Zurek, which only relies on causality to produce a freezout of order parameter fluctuations.Comment: 4 pages, 3 figure

Influences on Artistic Expression in Traditional Domestic Architecture of South West Nigeria

Over the years, art in its various forms has played a vital role in the lives of African people. It served as a major form of communicative expression of religious beliefs and sociocultural norms of the people. Its form, presentation and significance however, varied from one cultural setting to another. This paper examines art in the context of domestic architecture of indigenous people of South West Nigeria and factors that have influenced its transformation. The paper notes the disappearance of the rich meaning-laden traditional motifs and symbols from contemporary housing and their replacement with more contemporary art forms influenced by several forces including colonialism, expatriation of slaves and more recent forces of globalisation and industrial mass production. It concludes that the current trend presents an architecture that is devoid of cultural architectural uniqueness and identity. One of the implications identified is for architectural curricula to incorporate indigenous themes that will help architects produce domestic architecture that have contextual relevance. Data for the paper was collected through literature review and the qualitative research method using interviews and observations of houses in the study area. Those interviewed included professional architects and residents in the study area. Data was content analysed to highlight emerging common themes

De-carbonizing the Nigerian Housing Sector: The Role of Life Cycle CO2 Assessment

Carbon in the form of carbon dioxide (CO2) is the most important chemical compound in the climate change process as it is the main causative agent of global warming and climate change. International efforts aimed at arresting climate change are all directed at carbon elimination or reduction. Buildings especially residential buildings have been found to contribute substantially to climate change through the carbon emitted to the environment in the process of building procurement and use. This paper aims at tracking the CO2 content of the various activities and processes involved in building procurement and use in a Nigerian context with a view to indentifying the target areas for decarbonization. This is done by applying the life cycle CO2 assessment (LCCO2A) approach to a typical urban residential apartment building in Lagos, Nigeria’s most populous and urbanized city. In this respect, the ICE database and the activity based method were used to estimate the embodied and operational CO2 emissions associated with the case building. The study found that the embodied and operational emissions were significant when compared with baseline scenarios in other countries. Hence the paper concluded that de-carbonization strategies should be targeted at both the embodied and operational carbon emissions of buildings. The best result will be achieved if the de-carbonization efforts are combined with natural and active carbon sinks that exist in the study contex

Bridging The Housing Deficit In Nigeria: Energy And Co2 Emissions Implications

Affordable and decent housing constitute an important component of the urban infrastructure of any nation. In Nigeria, the housing deficit was estimated in the year 2012 to be about 17 million. Understandably, the huge financial and complex logistical implications of bridging the deficit appear to have dominated academic discussions on the subject matter. This paper attempts to address the energy and CO2 emissions implications of mitigating the huge housing deficit. Using a predominant urban social housing typology in the highly urbanized city of Lagos as a basis, the paper estimated the embodied energy and CO2 emissions associated with providing the additional housing units needed to bridge the deficit. The life cycle energy analysis framework was adopted for the study with the Inventory of Carbon and Energy (ICE) as the main source of embodied energy and CO2 coefficients. It was found that given a housing unit footprint of 120m2 and a building life span of 50 years, the embodied energy and CO2 emissions intensities for the prototype were 7378MJ/m2 and 589kg/m2 respectively. For the additional housing units, the above intensities translated to about 15.x 1012 MJ of embodied energy and 1.2 x 1012kg of CO2. With respect to the building components, the largest contributors to the embodied energy and carbon profile were the substructure, frame and upper floors as well as internal and external walls and the key materials for the components were cement and steel reinforcement. In order to reduce the estimated embodied energy and carbon impact of providing the additional housing needs, the targets for mitigation should be the concrete, steel reinforcement and envelope/partition materials of the building

EMPLOYEE PARTICIPATION IN DECISION-MAKING IN ARCHITECTURAL FIRMS

In this study, the participation of employee architects in decision making in architectural firms is investigated. This is with a view to identifying the organisational contexts that enhance employee participation in decision making. The impact of such participation on the performances of the firms was also assessed. This study was carried out through a questionnaire survey of employers of architects in Nigeria. In agreement with findings of previous studies, participation of the employees of the architectural firms in the study in decision making is low. Employee participation in decision making in the firms was dependent on the staffing strategy and proportion of junior staff in many cases. The positive impact of employee participation in decision making on firm performance varied with the nature of the decision. This study concludes that there is need for employers in architectural firms to identify the categories of decision that employees should be involved in and to modify their firm contexts to encourage participation where desired

Crystal structure of the catalytic fragment of murine poly(ADP-ribose) polymerase-2.

Poly(ADP-ribose) polymerase-1 (PARP-1) has become an important pharmacological target in the treatment of cancer due to its cellular role as a 'DNA-strand break sensor', which leads in part to resistance to some existing chemo- and radiological treatments. Inhibitors have now been developed which prevent PARP-1 from synthesizing poly(ADP-ribose) in response to DNA-breaks and potentiate the cytotoxicity of DNA damaging agents. However, with the recent discoveries of PARP-2, which has a similar DNA-damage dependent catalytic activity, and additional members containing the 'PARP catalytic' signature, the isoform selectivity and resultant pharmacological effects of existing inhibitors are brought into question. We present here the crystal structure of the catalytic fragment of murine PARP-2, at 2.8 A resolution, and compare this to the catalytic fragment of PARP-1, with an emphasis on providing a possible framework for rational drug design in order to develop future isoform-specific inhibitors

BRIDGING THE HOUSING DEFICIT IN NIGERIA: ENERGY AND CO2 EMISSIONS IMPLICATIONS

Affordable and decent housing constitute an important component of the urban infrastructure of any nation. In Nigeria, the housing deficit was estimated in the year 2012 to be about 17 million. Understandably, the huge financial and complex logistical implications of bridging the deficit appear to have dominated academic discussions on the subject matter. This paper attempts to address the energy and CO2 emission implications of mitigating the huge housing deficit. Using a predominant urban social housing typology in the highly urbanized city of Lagos as a basis, the paper estimated the embodied energy and CO2 emissions associated with providing the additional housing units needed to bridge the deficit. The life cycle energy analysis framework was adopted for the study with the Inventory of Carbon and Energy (ICE) as the main source of embodied energy and CO2 coefficients. It was found that given a housing unit footprint of 120m2 and a building life span of 50 years, the embodied energy and CO2 emissions intensities for the prototype were 7378MJ/m2 and 589kg/m2 respectively. For the additional housing units, the above intensities translated to about 15.x 1012 MJ of embodied energy and 1.2 x 1012kg of CO2. With respect to the building components, the largest contributors to the embodied energy and carbon profile were the substructure, frame and upper floors as well as internal and external walls and the key materials for the components were cement and steel reinforcement. In order to reduce the estimated embodied energy and carbon impact of providing the additional housing needs, the targets for mitigation should be the concrete, steel reinforcement and envelope/partition materials of the building

CATHEDRAL: A Fast and Effective Algorithm to Predict Folds and Domain Boundaries from Multidomain Protein Structures

We present CATHEDRAL, an iterative protocol for determining the location of previously observed protein folds in novel multidomain protein structures. CATHEDRAL builds on the features of a fast secondary-structure–based method (using graph theory) to locate known folds within a multidomain context and a residue-based, double-dynamic programming algorithm, which is used to align members of the target fold groups against the query protein structure to identify the closest relative and assign domain boundaries. To increase the fidelity of the assignments, a support vector machine is used to provide an optimal scoring scheme. Once a domain is verified, it is excised, and the search protocol is repeated in an iterative fashion until all recognisable domains have been identified. We have performed an initial benchmark of CATHEDRAL against other publicly available structure comparison methods using a consensus dataset of domains derived from the CATH and SCOP domain classifications. CATHEDRAL shows superior performance in fold recognition and alignment accuracy when compared with many equivalent methods. If a novel multidomain structure contains a known fold, CATHEDRAL will locate it in 90% of cases, with <1% false positives. For nearly 80% of assigned domains in a manually validated test set, the boundaries were correctly delineated within a tolerance of ten residues. For the remaining cases, previously classified domains were very remotely related to the query chain so that embellishments to the core of the fold caused significant differences in domain sizes and manual refinement of the boundaries was necessary. To put this performance in context, a well-established sequence method based on hidden Markov models was only able to detect 65% of domains, with 33% of the subsequent boundaries assigned within ten residues. Since, on average, 50% of newly determined protein structures contain more than one domain unit, and typically 90% or more of these domains are already classified in CATH, CATHEDRAL will considerably facilitate the automation of protein structure classification