3,334 research outputs found
The unseen planets of double belt debris disk systems
The gap between two component debris disks is often taken to be carved by
intervening planets scattering away the remnant planetesimals. We employ N-body
simulations to determine how the time needed to clear the gap depends on the
location of the gap and the mass of the planets. We invert this relation, and
provide an equation for the minimum planet mass, and another for the expected
number of such planets, that must be present to produce an observed gap for a
star of a given age. We show how this can be combined with upper limits on the
planetary system from direct imaging non-detections (such as with GPI or
SPHERE) to produce approximate knowledge of the planetary system.Comment: Accepted to MNRA
Beyond Markov Chains, Towards Adaptive Memristor Network-based Music Generation
We undertook a study of the use of a memristor network for music generation,
making use of the memristor's memory to go beyond the Markov hypothesis. Seed
transition matrices are created and populated using memristor equations, and
which are shown to generate musical melodies and change in style over time as a
result of feedback into the transition matrix. The spiking properties of simple
memristor networks are demonstrated and discussed with reference to
applications of music making. The limitations of simulating composing memristor
networks in von Neumann hardware is discussed and a hardware solution based on
physical memristor properties is presented.Comment: 22 pages, 13 pages, conference pape
Some serological studies in the horse in relation to the pathogenesis of chronic obstructive pulmonary disease
The study described in this thesis was designed to
examine some serological factors which may be involved
in the pathogenesis of chronic obstructive pulmonary
disease (C.O.P.D.) of horses.In the first section, zone electrophoresis of
normal horse serum on agarose gels (pH 8.6) was studied
and the serum electrophoretic profiles of normal and
C.O.P.D. affected horses and ponies were compared. No
differences between the serum electrophoretic profiles
of healthy and C.O.P.D. affected horses and ponies were
observed which could be attributed to the presence of the
disease.In the second section, the nature of the two
major, electrophoretically distinct antiproteases in
horse serum was investigated prior to examining the
possible association of antiprotease deficiency with
the onset of C.O.P.D. in the horse, analogous to the
association of the inherited dysproteinaemia of alpha-1
antitrypsin deficiency and chronic lung disease in
man. The electrophoretically faster antiprotease, a
functional homologue of human alpha-1 antitrypsin, was
shown to appear in the prealbumin region of horse serum
after acidic starch gel electrophoresis (pH 4.3). This
polymorphic antiprotease corresponded to the allele
products of the Pr locus of horse serum described by
Braend (1970). The genetically determined polymorphism
of the Pr antiprotease was examined by acid starch
gel electrophoresis, isoelectric focusing and immunofixation
electrophoresis. The occurrence of a second
antiprotease in the acidic prealbumin region of horse
serum was postulated, although its nature remains to
be established.The electrophoretically slower antiprotease of
horse serum was identified as alpha-2 macroglobulin,
and was shown to contribute 48 percent of the total
serum antiproteolytic activity. As in man, horse
alpha-2 macroglobulin is able to inhibit the proteolytic
activity of trypsin, but has only limited inhibitory
activity on its esterolytic activity. Native alpha-2
macroglobulin was shown to possess esterase activity
and the possible association of the macroglobulin and
plasma pseudocholinesterase is discussed. No inherited
polymorphism of horse alpha-2 macroglobulin was observed.The Pr antiprotease allele frequencies in healthy
and C.O.P.D. affected Thoroughbred horses were compared
and no significant differences were observed. There
was however an apparently increased frequency of the
PrW allele amongst C.O.P.D. affected horses and ponies
of mixed breeding, although the significance of this
observation could not be established. Significantly
increased levels of immunochemically measured circulating
Pr protein were observed in a C.O.P.D. affected
population, although no corresponding increase in
biochemically measured serum trypsin inhibitory
capacity (STIC) was observed in this same population.It was concluded that serum antiprotease deficiency
and consequent predisposition to the development of
C.O.P.D. was unlikely to occur in the horse, although
a possible deficiency of local bronchiolar antiproteases,
resulting in an increased chance of hypersensitization
to the protease antigens of the fungi
commonly incriminated in C .0 .P .D ., could not be excluded.In the third section the occurrence of a serum
homocytotropic antibody in the horse, homologous to
human IgE, was investigated. A passively transferable
homocytotropic antibody against Culicoides pulicaris
was demonstrated in the serum of horses and ponies
affected with recurrent seasonal dermatitis. Like
human IgE, this antibody is heat-labile, susceptible
to thiol reducing agents and persists for long periods
in homologous skin. The elution characteristics of
the horse antibody on DEAE-anion exchange chromatography
are similar to those of human IgE. Anti-human
IgE was shown to induce reversed anaphylaxis-like
reactions in horse skin and immunfluorescent studies
provided preliminary evidence of the binding of antihuman
IgE to horse mast cells. These observations
on the equine homocytotropic antibody satisfy Vaerman's
(1970) criteria of interspecies protein homology
suggesting that the antibody is homologue of human IgE
Impact of a high-involvement approach to customer satisfaction on employees and organizational performance
This study examined the impacts of high-involvement approaches to enhancing customer satisfaction within a professional services firm. The study identified supportive organizational factors and employee attitudes and behaviors. Employee, customer, and organizational impacts associated with the initiative also were identified. Ten employees were surveyed and six were interviewed. Survey data were neutral, meaning that the respondents neither agreed nor disagreed with the items. Empowerment measures however, were significantly and positively correlated to organizational commitment, job satisfaction, and engagement. Organizational supports include direction, vision, allowance and recognition for these customer-focused behaviors, and having a return on investment from customer orientation. Supportive employee attitudes include valuing strong customer relationships and active involvement. Supportive behaviors include team-wide customer orientation, immersion with customers, follow through, and consistency. Employee outcomes include self-efficacy, ownership, and a sense of reward and contribution. Customer outcomes include superior value and connection. Organizational outcomes include business health and return customers
Automating tide gauge quality control
Tide gauges provide a vital component in coastal flooding alert systems, and as a record of past events. They are used to record short duration extremes such as tsunamis, storm surges lasting a few hours, regular tides, and long term changes in relative sea-level. Globally, there is far more tide gauge data in existence than is available in the public domain for research. A significant factor obstructing the release of data is that quality control of tide-gauge records is still carried out with a great deal of manual inspection, and is therefore labour-intensive. Automated systems must carefully distinguish between spikes due to instrumental error and genuine rare extreme events; and between damaged instruments and still water. The National Oceanography Centre automatic quality control software aims to enable analysis of any high-frequency tide-gauge record around the world with minimal manual intervention or parameter selection. We demonstrate the implementation in Matlab and discuss the successes and challenges of the software
A compact to revitalise large-scale irrigation systems using a leadership-partnership-ownership âtheory of changeâ
In countries with transitional economies such as those found in South Asia, large-scale irrigation systems (LSIS) with a history of public ownership account for about 115 million ha (Mha) or approximately 45% of their total area under irrigation. In terms of the global area of irrigation (320 Mha) for all countries, LSIS are estimated at 130 Mha or 40% of irrigated land. These systems can potentially deliver significant local, regional and global benefits in terms of food, water and energy security, employment, economic growth and ecosystem services. For example, primary crop production is conservatively valued at about US$355 billion. However, efforts to enhance these benefits and reform the sector have been costly and outcomes have been underwhelming and short-lived. We propose the application of a 'theory of change' (ToC) as a foundation for promoting transformational change in large-scale irrigation centred upon a 'global irrigation compact' that promotes new forms of leadership, partnership and ownership (LPO). The compact argues that LSIS can change by switching away from the current channelling of aid finances controlled by government irrigation agencies. Instead it is for irrigators, closely partnered by private, public and NGO advisory and regulatory services, to develop strong leadership models and to find new compensatory partnerships with cities and other river basin neighbours. The paper summarises key assumptions for change in the LSIS sector including the need to initially test this change via a handful of volunteer systems. Our other key purpose is to demonstrate a ToC template by which large-scale irrigation policy can be better elaborated and discussed
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A linked data approach to publishing complex scientific workflows
Past data management practices in many fields of natural science, including climate research, have focused primarily on the final research output - the research publication - with less attention paid to the chain of intermediate data results and their associated metadata, including provenance. Data were often regarded merely as an adjunct to the publication, rather than a scientific resource in their own right. In this paper, we attempt to address the issues of capturing and publishing detailed workflows associated with the climate/research datasets held by the Climatic Research Unit (CRU) at the University of East Anglia. To this end, we present a customisable approach to exposing climate research workflows for the effective re-use of the associated data, through the adoption of linked-data principles, existing widely adopted citation techniques (Digital Object Identifier) and data exchange mechanisms (Open Archives Initiative Object Reuse and Exchange)
Experiences and perceptions of Spring Lane Sure Start Children's Centre
Spring Lane Sure Start Childrenâs Centre was designated in September 2007, and âofficially openedâ in February 2009. The Centre is housed in refurbished premises within a nursery/school complex in the heart of Northampton and offers diverse health, childcare, early education and support services delivered by a multi-professional team. These services and activities are available to children aged 0-5 years old, and their parents/carers, residing within a catchment area comprising eight âSuper Output Areasâ in the Castle and St. James ward of Northampton.
In April 2009, the Centre for Children and Youth (CCY) â a research centre based at The University of Northampton â was commissioned by Spring Lane Sure Start Childrenâs Centre to collate and gather evaluative data regarding experiences and perceptions of the Childrenâs Centre during its first year of activitie
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