1,399 research outputs found
Photoassociation spectra and the validity of the dipole approximation for weakly bound dimers
Photoassociation (PA) of ultracold metastable helium to the 2s2p manifold is
theoretically investigated using a non-perturbative close-coupled treatment in
which the laser coupling is evaluated without assuming the dipole
approximation. The results are compared with our previous study [Cocks and
Whittingham, Phys. Rev. A 80, 023417 (2009)] that makes use of the dipole
approximation. The approximation is found to strongly affect the PA spectra
because the photoassociated levels are weakly bound, and a similar impact is
predicted to occur in other systems of a weakly bound nature. The inclusion or
not of the approximation does not affect the resonance positions or widths,
however significant differences are observed in the background of the spectra
and the maximum laser intensity at which resonances are discernable. Couplings
not satisfying the dipole selection rule |J-1| <= J' <= |J+1| do not lead to
observable resonances.Comment: 5 pages, 2 figures; Minor textual revision
Thick film silicon growth techniques
Thick film silicon ribbons were produced by means of the edge-defined, film-fed growth (EFG) technique. EFG is a process by which single crystals may be grown having a shape controlled by the outside dimensions of a die, the growth taking place from an extremely thin film of liquid fed by capillary action from a crucible below. The principal problem to be overcome in the application of this process to the growth of thick film silicon ribbon relates to the material, such as the shaping die. For the method to operate, this die material must be wet by the liquid silicon. To preserve semiconductor quality, the liquid silicon must not react significantly with the die material. The most promising die material for this application appears to be SiC and SiC-SiO2 admixture. In this case good wetting occurs between the molten silicon and the SiC. C is a relatively unharmful contaminant of Si and additions of quartz to SiC are found to decrease the extent of reaction
Public Facilitation of Small Farmer Access to International Food Marketing Channels: An Empirical Analysis of the USDA Market Assistance Program in Armenia
With the continued globalization, rapid channel consolidation, increasing technology, capital, food safety and private grades and standards requirements, many small scale agricultural and horticultural producers from transitional and developing countries are rapidly becoming excluded from international agri-food marketing system. Consequently, governments and international agencies alike are reevaluating the structure, form, and delivery of their assistance programs as they search to identify new delivery mechanisms that can overcome the weaknesses that their traditional programs face within this new business environment. Their challenge is to design programs that facilitate the establishment of economically viable and sustainable market relationships and business models between small-scale producers and the international food marketing system that provide these financially distress producers access to the technological know-how, market knowledge and access, and financial and productive resources required to successively compete. Recent Central and Eastern European (CEE) experiences indicate that foreign direct investment and the entry of multinational firms have successfully facilitated small farmers access to international marketing channels. By entering markets with sufficient capital to ensure contract enforcement and support investment, multinational firms can overcome the pervasive hold-up and underinvestment problems plaguing the sector thereby stimulating investment and growth in agricultural production (Gow & Swinnen, 1998; 2001; Walkenhorst, 2000; Dries & Swinnen, 2004). For numerous reasons access to sufficient foreign direct investment or multinational firms may not be an option for many countries. The obvious question therefore becomes, can an alternative third-party facilitation mechanism for stimulating agriculture be identified apart from the private solutions found in Central and East Europe? Glover and Kusterer (1990), Porter and Philips-Howard (1997), Coulter et al (1999), Eaton and Shepherd (2001), and Simmons (2001) allude to the benefits of public agencies in facilitating firm farmer relationships. However as of now the literature has not identified nor extracted the critical processes and factors required in the design, development and establishment of long-run economically viable and sustainable business models that facilitate small producers' access to international food markets. In this research we develop a theoretical model explaining the critical processes and factors involved in the public facilitation of the establishment of economically sustainable marketing relationships between small producers and agroprocessors in the presence of financial distress and absence of effective enforcement mechanisms. The USDA Market Assistance Program (MAP) in Armenia is used to empirically test the theoretical model as it provides a natural experiment. Aremina's recovery is similar to those observed in other CEE countries; however Armenia's agricultural sector has not experienced the recovery found elsewhere. A key constraining factor has been the lack of foreign direct investment initiated solutions so successfully employed elsewhere (World Bank, 1999; 2002). Without the presence of private solutions that can create self-enforcing relationships and encourage relationship specific investment, the Armenian agricultural sector has remained in a sub optimal equilibrium characterized by deep financial distress and a general lack of investment. The only sub-sectors that have seen growth any growth have had MAP facilitation support. Thus what is unique is that the MAP project appears to provide a public solution rather than a private solution to the problem, as in all the previous research (Gow & Swinnen, 1998; 2001; Foster, 1999; Gow et al, 2000; Walkenhorst, 2000; Dries & Swinnen, 2004; Cocks & Gow, 2003). In order to examine the phenomena of establishment and development of sustainable inter-organizational marketing relationships within the context of Armenian agriculture, the USDA MAP project, and the goat industry, we have used mixed methodological approach combining qualitative and quantitative data collection. Approximately 100 semi-structured interviews were conducted with farmers, industry representatives, local experts, and USDA MAP personnel. In additional, an extensive enumerated survey was implemented questioning 2000 farmers in five sectors over 2003 and 2004. Based upon the extensive interviews 12 different business models and facilitation processes used by the USDA MAP were identified and a suitable stratified survey frame was designed to test the differences between these models. The theoretical model and empirical results indicate that the third party public facilitator, USDA MAP, is critical in facilitating the initial development of the channel and identifying a value proposition in a downstream market. However, economic sustainability requires that the public agency remain an arms-length third party facilitator, rather than being the leader in the development of the channel and thus an integral cog in the channel. The actual development of the marketing channel should be led by an entrepreneur who possesses both the ability to develop the marketing channel and who is trusted by the local community. By leading the development of the channel the private enforcement capital that is created through the development of the channel is created between the entrepreneur and the farmers. Over time this widens the self enforcing range of the relationship, therefore allowing greater shifts in market conditions and decreasing the risk of opportunistic behavior (Gow et al, 2000). By holding the trust and respect of the community the entrepreneur inherently holds private enforcement capital with the rest of the community equivalent to the present value of their reputation or trust individually and collectively with the community (Oliver & Gow, 2002). Additionally, the expectation of a value proposition of a downstream market creates the expectation of private enforcement capital between farmers the entrepreneur through the present value of future returns that the entrepreneur could earn from the value proposition (Gow et al, 2000). Thus the combination of the present value of the entrepreneur's reputation with the farmers in the short term combined with the longer term expectation of future returns through the value proposition and creates sufficient private enforcement capital for the immediate development of a self-enforcing relationship with the farmers.International Relations/Trade,
Thick film silicon growth techniques
Silicon ribbon growth experiments were conducted using orifices (dies) fabricated from SiC-SiO2 mixtures, fused quartz, SiC, and fine-grained, high density graphite. The best results were obtained from graphite dies. A number of different approaches was tried in modifying the thermal gradient in the dies and in holding the dies. The best results here were obtained from a 0.25-in. thick Mo disc holding a graphite die directly and fitting the die quite closely. Ribbon growths as wide as 9 mm were obtained, while the longest ribbon was 450 x 3.5 x 0.5 mm. Resistivities of ribbons grown from graphite dies have been measured over the range of 0.03 to 1.6 ohm-cm. Some thoughts and literature findings are presented regarding refractory oxide materials as potential orifices
Simultaneous description of four positive and four negative parity bands
The extended coherent state model is further extended in order to describe
two dipole bands of different parities. The formalism provides a consistent
description of eight rotational bands. A unified description for spherical,
transitional and deformed nuclei is possible. Projecting out the angular
momentum and parity from a sole state, the band acquires a
magnetic character, while the electric properties prevail for the other band.
Signatures for a static octupole deformation in some states of the dipole bands
are pointed out. Some properties which distinguish between the dipole band
states and states of the same parity but belonging to other bands are
mentioned. Interesting features concerning the decay properties of the two
bands are found. Numerical applications are made for Gd, Yb,
Th, Ra, U and Pu, and the results are
compared with the available data.Comment: 36 pages, 13 figures, 12 table
`In pursuit of the Nazi mind?' the deployment of psychoanalysis in the allied struggle against Germany
This paper discusses how psychoanalytic ideas were brought to bear in the Allied struggle against the Third Reich and explores some of the claims that were made about this endeavour. It shows how a variety of studies of Fascist psychopathology, centred on the concept of superego, were mobilized in military intelligence, post-war planning and policy recommendations for ‘denazification’. Freud's ideas were sometimes championed by particular army doctors and government planners; at other times they were combined with, or displaced by, competing, psychiatric and psychological forms of treatment and diverse studies of the Fascist ‘personality’. This is illustrated through a discussion of the treatment and interpretation of the deputy leader of the Nazi Party, Rudolf Hess, after his arrival in Britain in 1941
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A "novel" reading therapy programme for reading difficulties after a subarachnoid haemorrhage
Background: Although several treatments for acquired reading difficulties exist, few studies have explored the effectiveness of treatment for mild reading difficulties and treatment for reading difficulties associated with cognitive impairment.
Aims: This study explored the effectiveness of an individual strategy-based reading treatment of 11 sessions given to a female participant (IW) who had mild reading difficulties following a subarachnoid haemorrhage (SAH). The impact of treatment on reading ability, confidence and emotions associated with reading were investigated.
Methods & Procedures: Treatment focussed on the use of strategies to support IW’s memory when reading books, the use of a checklist to select appropriate reading materials, and increasing IW’s confidence in discussing the book she was reading with others. A person-centred approach and personally relevant materials were used throughout the treatment. Reading ability was assessed using the Gray Oral Reading Tests (GORT-4; Lee Wiederholt & Bryant, 2001), and IW’s perspective was obtained using the Reading Confidence and Emotions Questionnaire (RCEQ; see Cocks et al., 2010. Pre-treatment, post-treatment and maintenance (7 weeks post) assessments were undertaken, with an additional exit interview at the final time point.
Outcomes & Results: Gains were noted in reading rate, accuracy, comprehension, and confidence, with parallel increased pleasure gained from reading and reduced negative emotions and frustration. Self-reported gains included conversing with others about material read, verbal communication, and re-engagement with the identity of being a reader.
Conclusions: Strategy-based treatment resulted in positive gains in reading for pleasure, conversation, and identity, for an individual with mild chronic reading difficulties. Participant self-report and interview reveal the true value of this treatment for the individual. The positive results suggest that further research is warranted that investigates the effectiveness of strategy-based reading therapy approaches for others with acquired reading difficulties
A review of the changes of internal state related to high temperature creep of polycrystalline metals and alloys
When polycrystalline metals and their alloys are used at high temperature, creep deformation leads to changes in their internal state. The change in internal state manifests itself in many ways, but the two ways that concern us in this review are (i) the creation of internal stress arising from the strain incompatibility between grains and/or the formation of cell/sub-grain structures and (ii) a change in the material resistance. This review aims to provide a clear separation of these two concepts by exploring the origin of each term and how it is associated with the creep deformation mechanism. Experimental techniques used to measure the internal stress and internal resistance over different length-scales are critically reviewed. It is demonstrated that the interpretation of the measured values requires knowledge of the dominant creep deformation mechanism. Finally, the concluding comments provide a summary of the key messages delivered in this review and highlight the challenges that remain to be addressed
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