2,846 research outputs found
How the Ji’kmaqn Came to Spiro: Possible Additions to the Inventory of Sound-Making Instruments Depicted in the Spiro Engravings
While doing research on turtle shell rattles the author stumbled onto a photograph of a rare and unusual idiophone whose exact likeness appears twice in one of the engraved shell images from Spiro. This paper describes the instrument and the Spiro image and discusses how an instrument currently found only in the Maritime Provinces of Canada may have come to be portrayed on a marine shell cup found at Spiro
How many metals does it take to fix N2? A mechanistic overview of biological nitrogen fixation
During the process of biological nitrogen fixation, the enzyme nitrogenase catalyzes the ATP-dependent reduction of dinitrogen to ammonia. Nitrogenase consists of two component metalloproteins, the iron (Fe) protein and the molybdenum-iron (MoFe) protein; the Fe protein mediates the coupling of ATP hydrolysis to interprotein electron transfer, whereas the active site of the MoFe protein contains the polynuclear FeMo cofactor, a species composed of seven iron atoms, one molybdenum atom, nine sulfur atoms, an interstitial light atom, and one homocitrate molecule. This Perspective provides an overview of biological nitrogen fixation and introduces three contributions to this special feature that address central aspects of the mechanism and assembly of nitrogenase
Nitrogenase: A nucleotide-dependent molecular switch
In the simplest terms, the biological nitrogen cycle is the reduction of atmospheric dinitrogen (N2) to ammonia with the subsequent reoxidation ammonia to dinitrogen (1). At the reduction level of ammonia, nitrogen incorporated into precursors for biological macromolecules such as proteins and nucleic acids. Reoxidation of ammonia to dinitrogen ("denitrification") by a variety of microbes (by way of nitrite and other oxidation levels of nitrogen) leads to the depletion of the "fixed," biologically usable, nitrogen pool. Besides the relatively small contribution from commercial ammonical fertilizer production, replenishing of the nitrogen pool falls mainly to a limited number of physiologically diverse microbes (e.g. eubacteria and archaebacteria; free-living and symbiotic; aerobic and anaerobic) that contain the nitrogenase enzyme system
Contribution of the voluntary sector to mental health crisis care in England: protocol for a multimethod study.
Introduction - Timely access to the right kind of support for people experiencing a mental health crisis can be problematic. The voluntary sector (VS) plays a key role in providing support and enabling access, but there is a knowledge gap concerning its contribution and interface with public services in mental health crisis care.
Methods and analysis - This study aims to address this. The study has three empirical elements: (1) a national survey of voluntary sector organisations (VSOs) in England and national stakeholder interviews to develop a typology of organisations and interventions provided by VSOs; (2) detailed mapping of VS services in two regions through interviews and extending the national survey; (3) four case studies, identified from the regional mapping, of VS mental health crisis services and their interface with National Health Service (NHS) and local authority services, at both a system and individual level. Data collection will involve interviews with commissioners; VSO and NHS or local authority providers; and focus groups with people who have experience of VSO crisis support, both service users and carers; and mapping the crisis trajectory of 10 service users in each study site through narrative interviews with service users and informal carers to understand the experience of VSO crisis care and its impact.
Ethics and dissemination - The University of Birmingham Humanities and Social Sciences Ethical Review Committee granted ethical approval (reference ERN_16-1183) for the national and regional elements of the study. Ethical review by the Health Research Authority will be required for the case study research once the sites have been identified from the first two elements of the study. A range of methods including a policy seminar, publication in academic journals and a tool kit for commissioners and practitioners will be produced to maximise the impact of the findings on policy and practice
A REST Model for High Throughput Scheduling in Computational Grids
Current grid computing architectures have been based on cluster management and batch queuing systems, extended to a distributed, federated domain. These have shown shortcomings in terms of scalability, stability, and modularity. To address these problems, this dissertation applies architectural styles from the Internet and Web to the domain of generic computational grids. Using the REST style, a flexible model for grid resource interaction is developed which removes the need for any centralised services or specific protocols, thereby allowing a range of implementations and layering of further functionality. The context for resource interaction is a generalisation and formalisation of the Condor ClassAd match-making mechanism. This set theoretic model is described in depth, including the advantages and features which it realises. This RESTful style is also motivated by operational experience with existing grid infrastructures, and the design, operation, and performance of a proto-RESTful grid middleware package named DIRAC. This package was designed to provide for the LHCb particle physics experiment's âワoff-lineâ computational infrastructure, and was first exercised during a 6 month data challenge which utilised over 670 years of CPU time and produced 98 TB of data through 300,000 tasks executed at computing centres around the world. The design of DIRAC and performance measures from the data challenge are reported. The main contribution of this work is the development of a REST model for grid resource interaction. In particular, it allows resource templating for scheduling queues which provide a novel distributed and scalable approach to resource scheduling on the grid
Higher education and employment in Kenya: a liberal interpretation of the literature
This paper is an attempt to synthesize and interpret the literature on higher education and employment of the highly-trained in Kenya. The paper begins by examining four trends which characterise the labour market for university graduates in the 1980's. These trends are the,
1) Low employment generation in the private sector and the subsequent pressure on the government to provide jobs;
2) Increasing competition among graduates for desirable employment;
3) Occurrence of education or credential inflation, particularly at the entry-level; and,
4) Limited, but one-way, public to private sector movement of skilled persons.
The relationship of these trends has a number of parallels with the classic inflationary spiral. The demand for education places an unending pressure on the government to expand the educational system, which in turn results in subsequent pressure to expand employment opportunities, which reinforces the demand for education (by assuring that relatively high-paying jobs are available). The government cannot maintain the increasing commitment of resources necessary to continue to expand the educational system and employ its graduates.
The paper concludes with an examination of some selected policy options. The pervasive theme and intent of these strategies are to reduce the role that the government plays in subsidizing of higher levels of education and the provision of employment for the highly-trained. Changes must also occur on the individual level. Greater responsibility must be shifted to the consumer of education to be informed of available training alternatives, to assume a greater proportion of the costs of that education, to be aware of employment prospects and realities, and to be prepared to accept the outcomes, whatever they may be
Welfare to work initiatives: understanding the politics of subcontracted service delivery
Drawing on empirical research on the recent Work Programme, Rebecca Taylor, James Rees, and Christopher Damm explain how providers from the public, private, and third sector experienced delivering it; and how the supply chain model worked
Public sector commissioning of local mental health services from the third sector:Third Sector Research Centre Working Paper 122
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