34,732 research outputs found
Incorporation of nitrogen from crop residues into light fraction organic matter in soils with contrasting management histories
The proportion of N from crop residues entering the light-fraction organic matter (LFOM) pool was investigated in soils with contrasting soil organic matter and microbial characteristics arising from different management histories. A laboratory experiment was conducted in which 15N-labelled sugar beet, Brussels sprout or ryegrass shoots, which possessed a range of C/N contents, and hence different biochemical qualities, were incorporated into a sandyâloam soil collected from within a field (FC) or from the field margin (FM). Amounts of C and N incorporated into LFOM were determined after 112 days. The FC and FM soils had organic C contents of 0.9% and 2.5%, respectively. Addition of crop residues increased total LFOM N content and reduced its C/N in FC soil but had no effect on total LFOM N or its C/N in FM soil. Ryegrass incorporation into FC was the only treatment in which there was a net increase in LFOM C. Isotopic analysis indicated that more crop-residue-derived N became incorporated into the LFOM N pool in FM relative to FC soil, with per cent crop residue N incorporated ranging from 25.9% to 35.3% in FC and between 38.9 and 68.5 in FM. Incorporation of crop residues had a positive priming effect on pre-existing LFOM N in FM but not FC soil. We conclude that the characteristics of plant material, together with differences in soil organic matter and microbiology resulting from contrasting management, determined the amount of crop residue C and N incorporated into both HFOM and LFOM
A review of key planning and scheduling in the rail industry in Europe and UK
Planning and scheduling activities within the rail industry have benefited from developments in computer-based simulation and modelling techniques over the last 25 years. Increasingly, the use of computational intelligence in such tasks is featuring more heavily in research publications. This paper examines a number of common rail-based planning and scheduling activities and how they benefit from five broad technology approaches. Summary tables of papers are provided relating to rail planning and scheduling activities and to the use of expert and decision systems in the rail industry.EPSR
Turbulent Mixing in the Outer Solar Nebula
The effects of turbulence on the mixing of gases and dust in the outer Solar
nebula are examined using 3-D MHD calculations in the shearing-box
approximation with vertical stratification. The turbulence is driven by the
magneto-rotational instability. The magnetic and hydrodynamic stresses in the
turbulence correspond to an accretion time at the midplane about equal to the
lifetimes of T Tauri disks, while accretion in the surface layers is thirty
times faster. The mixing resulting from the turbulence is also fastest in the
surface layers. The mixing rate is similar to the rate of radial exchange of
orbital angular momentum, so that the Schmidt number is near unity. The
vertical spreading of a trace species is well-matched by solutions of a damped
wave equation when the flow is horizontally-averaged. The damped wave
description can be used to inexpensively treat mixing in 1-D chemical models.
However, even in calculations reaching a statistical steady state, the
concentration at any given time varies substantially over horizontal planes,
due to fluctuations in the rate and direction of the transport. In addition to
mixing species that are formed under widely varying conditions, the turbulence
intermittently forces the nebula away from local chemical equilibrium. The
different transport rates in the surface layers and interior may affect
estimates of the grain evolution and molecular abundances during the formation
of the Solar system.Comment: To appear in the Astrophysical Journal; 20 pages, 9 figure
Three and Four Region Multi-sector Linear Modelling Using UK Data : Some Preliminary Results
Scotland and Wales have relatively up-to-date, independently generated, IO tables. These can be separated out from a UK national IO table to construct an inter-regional table. We therefore undertake the detailed analysis at this three-region (Scotland, Wales and the Rest of the UK (RUK)) level, where the Rest of the UK is England and Northern Ireland. However, we also construct a more rudimentary four-region (Scotland, Wales, England and Ireland) set of IO and SAM accounts by constructing a separate Northern Ireland accounts. The inter-regional IO and SAM models are produced for the year 1999. This was determined by the availability of consistent data. In Section II we describe the construction of a three-region Input-Output model for the United Kingdom, which includes the regions of Scotland, Wales and the Rest of the UK (RUK). In Section III we extend the three-region model to construct an inter-regional Social Accounting Matrix. Section IV reports some results using the three-region IO and SAM models. In Section V, we generate a four-region IO and SAM model for the UK, which disaggregates Northern Ireland from the Rest of the UK, and provide some results using the four-region IO and SAM models. Section VI offers our conclusions
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What is the impact of psychiatric decision units on mental health crisis care pathways? Protocol for an interrupted time series analysis with a synthetic control study
Background
The UK mental health system is stretched to breaking point. Individuals presenting with mental health problems wait longer at the ED than those presenting with physical concerns and finding a bed when needed is difficult â 91% of psychiatric wards are operating at above the recommended occupancy rate. To address the pressure, a new type of facility â psychiatric decision units (also known as mental health decision units) â have been introduced in some areas. These are short-stay facilities, available upon referral, targeted to help individuals who may be able to avoid an inpatient admission or lengthy ED visit. To advance knowledge about the effectiveness of this service for this purpose, we will examine the effect of the service on the mental health crisis care pathway over a 4-year time period; the 2 years proceeding and following the introduction of the service. We use aggregate service level data of key indicators of the performance of this pathway.
Methods
Data from four mental health Trusts in England will be analysed using an interrupted time series (ITS) design with the primary outcomes of the rate of (i) ED psychiatric presentations and (ii) voluntary admissions to mental health wards. This will be supplemented with a synthetic control study with the same primary outcomes, in which a comparable control group is generated for each outcome using a donor pool of suitable National Health Service Trusts in England. The methods are well suited to an evaluation of an intervention at a service delivery level targeting population-level health outcome and the randomisation or âtrialabilityâ of the intervention is limited. The synthetic control study controls for national trends over time, increasing our confidence in the results. The study has been designed and will be carried out with the involvement of service users and carers.
Discussion
This will be the first formal evaluation of psychiatric decision units in England. The analysis will provide estimates of the effect of the decision units on a number of important service use indicators, providing much-needed information for those designing service pathways
A software architecture for autonomous maintenance scheduling: Scenarios for UK and European Rail
A new era of automation in rail has begun offering developments in the operation and maintenance of industry standard systems. This article documents the development of an architecture and range of scenarios for an autonomous system for rail maintenance planning and scheduling. The Unified Modelling Language (UML) has been utilized to visualize and validate the design of the prototype. A model for information exchange between prototype components and related maintenance planning systems is proposed in this article. Putting forward an architecture and set of usage mode scenarios for the proposed system, this article outlines and validates a viable platform for autonomous planning and scheduling in rail
An extension and application of the Leontief pollution model for waste generation and disposal in Scotland
Solid waste generation, treatment and disposal are important policy concerns for the Scottish Parliament. As a result of the Environment Act 1995, a National Waste Strategy for Scotland was introduced with the general aim of reducing the amount of waste produced and dealing with what is produced in more sustainable ways. This implies the need for an empirical framework to inform policymakers regarding the relationship between economic activity and waste generation, treatment and disposal and the likely impacts of any policy actions or other disturbances on all types of sustainability indicators. In this paper we report on a study to develop an extended input-output (IO) system of the type originally proposed in the seminal paper by Leontief (1970). This involves extending the standard IOaccounts to take account of pollution or waste generation as an additional output accompanying production and consumption activities in the economy and of the activity required to clean up (or prevent) these unwanted outputs. The extension of IO tables to take account of pollution/waste generation is relatively widespread in the literature. It is usually achieved through the introduction of physical pollution/waste-output coefficients, and has been previously applied to Scotland for the case ofair pollution (see McNicoll & Blackmore, 1993, McGregor et al, 2001). Such an approach allows us to examine the impact of the economy on the environment, in terms of the amount of pollution/waste emitted as a result of economic activity. However, it does not allow us to track the feedback from the environment to the economy in terms of the resources used in environmental cleaning. If we areinterested in this aspect, we need to identify the input structure of any pollution abatement or waste disposal activities and identify columns in the IO tables representing cleaning activities
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Identification of Trace Organic Components in the CR Chondrites by 4D TOFMS
This paper reports preliminary results of a 4D TOFMS study of CR chondrite organic material, highlighting the low-level organic species that may further reveal the complexity of parent body modification of interstellar precursors
An intelligent framework and prototype for autonomous maintenance planning in the rail industry
This paper details the development of the AUTONOM project, a project that aims to provide an enterprise system tailored to the planning needs of the rail industry. AUTONOM extends research in novel sensing, scheduling, and decision-making strategies customised for the automated planning of maintenance activities within the rail industry. This paper sets out a framework and software prototype and details the current progress of the project. In the continuation of the AUTONOM project it is anticipated that the combination of techniques brought together in this work will be capable of addressing a wider range of problem types, offered by Network rail and organisations in different industries
Atmospheric environment for space shuttle (STS-8) launch
Selected atmospheric conditions observed near Space Shuttle STS-8 launch time on August 30, 1983, at Kennedy Space Center, Florida are summarized. Values of ambient pressure, temperature, moisture, ground winds, visual observations (cloud), and winds aloft are included. The sequence of prelaunch Jimsphere measured vertical wind profiles is given. Also presented are wind and thermodynamic parameters representative of surface and aloft conditions in the SRB descent/impact ocean area. Final meteorological tapes, which consist of wind and thermodynamic parameters versus altitude, for STS-8 vehicle ascent and SRB descent/impact were constructed. The STS-8 ascent meteorological data tape was constructed
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