63,410 research outputs found
Construction of pseudo-bosons systems
In a recent paper we have considered an explicit model of a PT-symmetric
system based on a modification of the canonical commutation relation. We have
introduced the so-called {\em pseudo-bosons}, and the role of Riesz bases in
this context has been analyzed in detail. In this paper we consider a general
construction of pseudo-bosons based on an explicit {coordinate-representation},
extending what is usually done in ordinary supersymmetric quantum mechanics. We
also discuss an example arising from a linear modification of standard creation
and annihilation operators, and we analyze its connection with coherent states.Comment: In press in Journal of Mathematical Physic
The refractive characteristics and intraocular tensions of colony chimpanzees Technical report, Aug. 1965
Refraction and intraocular pressure tests of colony chimpanzees - age relationshi
TILAPIA: BOTH FISH AND FOWL?
Tilapia aquaculture production is now around one million tonnes and is widely tipped to become an even bigger player in the international arena. This paper considers the case for such claims by reviewing the production environment, costs, the key characteristics of the product and its marketing with particular reference to the emergent EU markets and the increasingly established North American market. It is concluded that tilapia has quite distinct comparative advantages, not least being its diverse production scenarios, low cost, and product attributes which are commonly sought by consumers. Coupled with potentially green marketing attributes, it is concluded that this species is likely to appear in a broadening product range including more added value products.Resource /Energy Economics and Policy,
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Kinosternon integrum
Number of Pages: 6Integrative BiologyGeological Science
Ultrasound and phakometry measurements of the primate eye Technical report, Aug. 1965
Ultrasonic testing and phakometry measurements of primate ey
Time to publication for NIHR HTA programme-funded research: a cohort study
ObjectiveTo assess the time to publication of primary research and evidence syntheses funded by the National Institute for Health Research (NIHR) Health Technology Assessment (HTA) Programme published as a monograph in Health Technology Assessment and as a journal article in the wider biomedical literature.Study designRetrospective cohort study.SettingPrimary research and evidence synthesis projects funded by the HTA Programme were included in the cohort if they were registered in the NIHR research programmes database and was planned to submit the draft final report for publication in Health Technology Assessment on or before 9 December 2011.Main outcome measuresThe median time to publication and publication at 30?months in Health Technology Assessment and in an external journal were determined by searching the NIHR research programmes database and HTA Programme website.ResultsOf 458 included projects, 184 (40.2%) were primary research projects and 274 (59.8%) were evidence syntheses. A total of 155 primary research projects had a completion date; the median time to publication was 23?months (26.5 and 35.5?months to publish a monograph and to publish in an external journal, respectively) and 69% were published within 30?months. The median time to publication of HTA-funded trials (n=126) was 24?months and 67.5% were published within 30?months. Among the evidence syntheses with a protocol online date (n=223), the median time to publication was 25.5?months (28?months to publication as a monograph), but only 44.4% of evidence synthesis projects were published in an external journal. 65% of evidence synthesis studies had been published within 30.0?months.ConclusionsResearch funded by the HTA Programme publishes promptly. The importance of Health Technology Assessment was highlighted as the median time to publication was 9?months shorter for a monograph than an external journal article
Ensemble dependence in the Random transverse-field Ising chain
In a disordered system one can either consider a microcanonical ensemble,
where there is a precise constraint on the random variables, or a canonical
ensemble where the variables are chosen according to a distribution without
constraints. We address the question as to whether critical exponents in these
two cases can differ through a detailed study of the random transverse-field
Ising chain. We find that the exponents are the same in both ensembles, though
some critical amplitudes vanish in the microcanonical ensemble for correlations
which span the whole system and are particularly sensitive to the constraint.
This can \textit{appear} as a different exponent. We expect that this apparent
dependence of exponents on ensemble is related to the integrability of the
model, and would not occur in non-integrable models.Comment: 8 pages, 12 figure
Economic Comparison of the Undercutter and Traditional Tillage Systems for Winter Wheat-Summer Fallow Farming
Wind erosion and blowing dust are major problems for traditional tillage winter wheat-summer fallow in eastern Washington. Wind erosion reduces soil productivity and dust particulates are a major air quality concern. Conservation tillage summer fallow can reduce wind erosion markedly, but is used by relatively few farmers in the low-precipitation (less than 12 inch/year) region of the Inland Pacific Northwest. Barriers to adoption include the cost of conservation tillage implements and reluctance to change "tried and proven"traditional tillage methods. This bulletin compares economic results for the V-sweep undercutter and traditional fallow tillage systems on a case study farm located near Ritzville, WA. The farm’s eight-year average wheat yield is 46 bu/ac. Grain yields are similar for the two systems. This study shows that the undercutter method of summer fallow farming is more profitable than the traditional system on the case study farm due to slightly lower production costs. The undercutter system is eligible for conservation payments, but the traditional system is not. Receipt of these payments further strengthens the profitability advantage of the undercutter systemcapital, labor, land and management resources, type and size of machinery complement
Studies of laser and laser devices
The generation of tunable, infrared, and ultraviolet light, and the control of this light by mode-locking and modulation techniques are discussed. Particular emphasis is given to energy storage and extraction using atomic levels, the development of a tunable narrowband vacuum ultraviolet light source, and to the generation and applications of ultrashort optical pulses
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