3,112 research outputs found
Middle atmosphere project. A semi-spectral numerical model for the large-scale stratospheric circulation
The complete model is a semispectral model in which the longitudinal dependence is represented by expansion in zonal harmonics while the latitude and height dependencies are represented by a finite difference grid. The model is based on the primitive equations in the log pressure coordinate system. The lower boundary of the model domain is set at the 100 mb level (i.e., near the tropopause) and the effects of tropospheric forcing are included in the lower boundary condition. The upper boundary is at approximately 96 km, and the latitudinal extent is either global or hemispheric. The basic differential equations and boundary conditions are outlined. The finite difference equations are described. The initial conditions are discussed and a sample calculation is presented. The FORTRAN code is given in the appendix
Viscosity Information from Relativistic Nuclear Collisions: How Perfect is the Fluid Observed at RHIC?
Relativistic viscous hydrodynamic fits to RHIC data on the centrality
dependence of multiplicity, transverse and elliptic flow for sqrt{s}=200 GeV
Au+Au collisions are presented. For Glauber-type initial conditions, while data
on integrated v_2 is consistent with a ratio of viscosity over entropy density
up to eta/s=0.16, data on minimum bias v_2 seems to favor a much smaller
viscosity over entropy ratio, below the bound from the AdS/CFT conjecture. Some
caveats on this result are discussed.Comment: 4 pages, 5 figures; v2: matches published version, title changed by
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Memory, persons and dementia
Memory is a complex phenomenon, so the loss of memory that occurs in dementia is equally complex. Accounts that deny personhood to dementia sufferers typically fail to accommodate that complexity. This is the author accepted manuscript. The final version is available from SAGE Publications via http://dx.doi.org/10.1177/095394681664296
Experiment requirements: Vitamin D metabolites and bone demineralization, Spacelab 2, experiment no. 1
As a contribution toward an understanding of the molecular basis of bone loss, mineral imbalance, and increasing fecal calcium under conditions of prolonged space flight, the blood levels of biologically active vitamin D metabolites of flight crew members will be quantitatively measured. Prior to the mission, the refinement of existing and the development of new techniques for the assay of all vitamin D metabolites will provide an arsenal of methods suitable for a wide range of metabolite levels. In terms of practical application, the analysis of human and animal plasma samples, Spacelab crew plasma samples, and flight hardware are envisioned
The temporal response of bone to unloading
Rats were suspended by their tails with the forelimbs bearing the weight load to simulate the weightlessness of space flight. Growth in bone mass ceased by 1 week in the hindlimbs and lumbar vertebrae in growing rats, while growth in the forelimbs and cervical vertebrae remained unaffected. The effects of selective skeletal unloading on bone formation during 2 weeks of suspension was investigated using radio iostope incorporation (with Ca-45 and H-3 proline) and histomorphometry (with tetracycline labeling). The results of these studies were confirmed by histomorphometric measurements of bone formation using triple tetracycline labeling. This model of simulated weightlessness results in an initial inhibition of bone formation in the unloaded bones. This temporary cessation of bone formation is followed in the accretion of bone mass, which then resumes at a normal rate by 14 days, despite continued skeletal unloading. This cycle of inhibition and resumption of bone formation has profound implication for understanding bone dynamics durng space flight, immobilization, or bed rest and offers an opportunity to study the hormonal and mechanical factors that regulate bone formation
Developing a sector sustainability strategy for the UK precast concrete industry
Sector sustainability strategies can provide industry sectors with a way of managing risks
and opportunities, and contributing to sustainable development. The UK Government has
encouraged their development in the construction industry. British Precast, as the trade
association for the precast concrete industry in the UK, had undertaken to develop a
sector sustainability strategy for that industry. However, the development of such
strategies is a departure from the traditional role of the trade association and presented
British Precast with a number of challenges. This EngD research programme was
therefore established in order to address those challenges and facilitate progress towards a
more sustainable precast industry.
The research programme has followed a mixed method strategy of inquiry based on
action research methodology, that is, a series of research cycles have been undertaken
with the findings from each cycle being used to inform and guide subsequent cycles;
archival analysis, survey and case study were the main research methods used. The
requirement of the EngD programme to publish elements of the work in refereed journal
and conference papers as the research progresses has allowed the research to be validated
as scientifically satisfactory.
The strategy development process combined best practice, current and emerging theory,
original research, stakeholder engagement, and experience from other sectors and
industries. The strategy was produced in the form of an action plan for British Precast.
This plan differs from the sustainability strategies produced for other sectors of the
construction products industry in that rather than simply promoting action on specific
objectives, it provides British Precast with a means of engaging with the industry and its
stakeholders, and facilitating progress towards a more sustainable precast industry. The
action plan has been well received by the industry and its stakeholders, and there is clear
evidence that it is helping to guide the business decisions of companies in the industry,
and that progress towards a more sustainable precast industry is being achieved as a
result.
The research supporting the strategy development process has added to current
knowledge and guidance on the development of sector sustainability strategies, but shown
that there are limits to the influence trade associations can have over their members’
actions. It has also been shown that the development of management systems, particularly
environmental management systems to ISO 14001, and continuous performance
improvement cultures can assist companies in managing for sustainability, supporting the
findings of other studies. However, further work is needed to build support for the action
plan within the precast industry, particularly amongst SMEs, to support the downstream
supply chain in using precast products to deliver more sustainable construction, and to
assist companies in achieving progress towards corporate sustainability.
Recommendations are made for this work
Trust and trustworthiness
What is it to trust someone? What is it for someone to be trustworthy? These are the two main questions that this paper addresses. There are various situations that can be described as ones of trust, but this paper considers the issue of trust between individuals. In it, I suggest that trust is distinct from reliance or cases where someone asks for something on the expectation that it will be done due to the different attitude taken by the trustor. I argue that the trustor takes Holton's 'participant stance' and this distinguishes trust from reliance. I argue that trustworthiness is different from reliability and that an account of trustworthiness cannot be successful whilst ignoring the point that aligning trustworthiness with reliability removes the virtue from being trustworthy. On the question of what it is distinguishes trustworthiness from reliability, I argue that the distinction is in the opportunity for the trustee to act against the wishes of the trustor and the trustee's consideration of the value of the trust that has been placed in them by the trustor
On the spectrum of vertically propagating gravity waves generated by a transient heat source
It is commonly believed that cumulus convection preferentially generates gravity waves with tropospheric vertical wavelengths approximately twice the depth of the convective heating. Individual cumulonimbus, however, act as short term transient heat sources (duration 10 to 30min). Gravity waves generated by such sources have broad frequency spectra and a wide range of vertical scales. The high-frequency components tend to have vertical wavelengths much greater than twice the depth of the heating. Such waves have large vertical group velocities, and are only observed for a short duration and at short horizontal distances from the convective source. At longer times and longer distances from the source the dominant wave components have short vertical wavelengths and much slower group velocities, and thus are more likely to be observed even though their contribution to the momentum flux in the upper stratosphere and mesosphere may be less than that of the high frequency waves. These properties of convectively generated waves are illustrated by a linear numerical model for the wave response to a specified transient heat source. The wave characteristics are documented through Fourier and Wavelet analysis, and implications for observing systems are discussed
A Model Study of Zonal Forcing in the Equatorial Stratosphere by Convectively Induced Gravity Waves
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