Multimodal spectral control of a quantum-dot diode laser for THz difference frequency generation

Generation of stable dual and/or multiple longitudinal modes emitted from a single quantum dot (QD) laser diode (LD) over a broad wavelength range by using volume Bragg gratings (VBG's) in an external cavity setup is reported. The LD operates in both the ground and excited states and the gratings give a dual-mode separation around each emission peak of 5 nm, which is suitable as a continuous wave (CW) optical pump signal for a terahertz (THz) photomixer device. The setup also generates dual modes around both 1180m and 1260 nm simultaneously, giving four simultaneous narrow linewidth modes comprising two simultaneous difference frequency pump signals. (C) 2011 American Institute of Physics.

Direct observation of R...R distances in rare-earth (R) phosphate glasses by magnetic difference neutron diffraction

A magnetic difference neutron diffraction study of a rare-earth (Tb) phosphate glass has revealed exclusively the Tb...Tb distances. The difference between data taken with and without an applied magnetic field of 4 T shows Tb...Tb pairwise atomic correlations at 3.9 and 6.4 A, respectively, with relative coordination numbers of 1:14. The first distance arises when two Tb3+ ions share a common oxygen neighbor, and indicates a clustering of rare-earth ions. The second distance arises when two Tb3+ ions are coordinated to different oxygens in the same PO4 group, in a near-linear arrangement.

What difference doguidelines make? An observational study of online-questionnaire design guidelines put to practical use

As a new medium for questionnaire delivery, the Internet has the potential to revolutionize the survey process. Online-questionnaires can provide many capabilities not found in traditional paper-based questionnaires. Despite this, and the introduction of a plethora of tools to support online-questionnaire creation, current electronic survey design typically replicates the look-and-feel of paper-based questionnaires, thus failing to harness the full power of the electronic delivery medium. A recent environmental scan of online-questionnaire design tools found that little, if any, support is incorporated within these tools to guide questionnaire designers according to best-practice [Lumsden & Morgan 2005]. This paper briefly introduces a comprehensive set of guidelines for the design of online-questionnaires. Drawn from relevant disparate sources, all the guidelines incorporated within the set are proven in their own right; as an initial assessment of the value of the set of guidelines as a practical reference guide, we undertook an informal study to observe the effect of introducing the guidelines into the design process for a complex online-questionnaire. The paper discusses the qualitative findings — which are encouraging for the role of the guidelines in the ‘bigger picture’ of online survey delivery across many domains such as e-government, e-business, and e-health — of this case study.

Representational difference analysis:Critical appraisal and method development for the identification of unique DNA sequences from prokaryotes

Representational difference analysis (RDA) has great potential for preferential amplification of unique but uncharacterised DNA sequences present in one source such as a whole genome, but absent from a related genome or other complex population of sequences. While a few examples of its successful exploitation have been published, the method has not been well dissected and robust, detailed published protocols are lacking. Here we examine the method in detail, suggest improvements and provide a protocol that has yielded key unique sequences from a pathogenic bacterial genome. © 2003 Elsevier Science B.V. All rights reserved.

Development of a passive MEG stimulus for measurement of the binaural masking level difference

The ability to hear a target signal over background noise is an important aspect of efficient hearing in everyday situations. This mechanism depends on binaural hearing whenever there are differences in the inter-aural timing of inputs from the noise and the signal. Impairments in binaural hearing may underlie some auditory processing disorders, for example temporal-lobe epilepsies. The binaural masking level difference (BMLD) measures the advantage in detecting a tone whose inter-aural phase differs from that of the masking noise. BMLD’s are typically estimated psychophysically, but this is challenging in children or those with cognitive impairments. The aim of this doctorate is to design a passive measure of BMLD using magnetoencephalography (MEG) and test this in adults, children and patients with different types of epilepsy. The stimulus consists of Gaussian background noise with 500-Hz tones presented binaurally either in-phase or 180° out-of-phase between the ears. Source modelling provides the N1m amplitude for the in-phase and out-of-phase tones, representing the extent of signal perception over background noise. The passive BMLD stimulus is successfully used as a measure of binaural hearing capabilities in participants who would otherwise be unable to undertake a psychophysical task.

Analog of Favard's Theorem for Polynomials Connected with Difference Equation of 4-th Order

Orthonormal polynomials on the real line {pn (λ)} n=0 ... ∞ satisfy the recurrent relation of the form: λn−1 pn−1 (λ) + αn pn (λ) + λn pn+1 (λ) = λpn (λ), n = 0, 1, 2, . . . , where λn > 0, αn ∈ R, n = 0, 1, . . . ; λ−1 = p−1 = 0, λ ∈ C. In this paper we study systems of polynomials {pn (λ)} n=0 ... ∞ which satisfy the equation: αn−2 pn−2 (λ) + βn−1 pn−1 (λ) + γn pn (λ) + βn pn+1 (λ) + αn pn+2 (λ) = λ2 pn (λ), n = 0, 1, 2, . . . , where αn > 0, βn ∈ C, γn ∈ R, n = 0, 1, 2, . . ., α−1 = α−2 = β−1 = 0, p−1 = p−2 = 0, p0 (λ) = 1, p1 (λ) = cλ + b, c > 0, b ∈ C, λ ∈ C. It is shown that they are orthonormal on the real and the imaginary axes in the complex plane ...

On the Difference of 4-Gonal Linear Systems on some Curves

Let C = (C, g^1/4 ) be a tetragonal curve. We consider the scrollar invariants e1 , e2 , e3 of g^1/4 . We prove that if W^1/4 (C) is a non-singular variety, then every g^1/4 ∈ W^1/4 (C) has the same scrollar invariants.

Nonstandard Finite Difference Schemes with Application to Finance: Option Pricing

2000 Mathematics Subject Classification: 65M06, 65M12.

Low Volatility Options and Numerical Diffusion of Finite Difference Schemes

2000 Mathematics Subject Classification: 65M06, 65M12.

Oscillation Criteria of Second-Order Quasi-Linear Neutral Delay Difference Equations

2000 Mathematics Subject Classification: 39A10.

Making a difference:critical linguistic analysis in a legal context

One of the major problems for Critical Discourse Analysts is how to move on from their insightful critical analyses to successfully 'acting on the world in order to transform it'. This paper discusses, with detailed exemplification, some of the areas where linguists have moved beyond description to acting on and changing the world. Examples from three murder trials show how essential it is, in order to protect the rights of witnesses and defendants, to have audio records of significant interviews with police officers. The article moves on to discuss the potentially serious consequences of the many communicative problems inherent in legal/lay interaction and illustrates a few of the linguist-led improvements to important texts. Finally, the article turns to the problems of using linguistic data to try to determine the geographical origin of asylum seekers. The intention of the article is to act as a call to arms to linguists; it concludes with the observation that 'innumerable mountains remain for those with a critical linguistic perspective who would like to try to move one'. © 2011 John Benjamins Publishing Company.

Does the balanced scorecard make a difference to the strategy development process

A great number of strategy tools are being taught in strategic management modules. These tools are available to managers for use in facilitating strategic decision making and enhancing the strategy development process in their organisations. A number of studies have been published examining which are the most popular tools; however there is little empirical evidence on how their utilisation influences the strategy process. This paper is based on a large scale international survey on the strategy development process, and seeks to examine the impact of a particular strategy tool, the Balanced Scorecard (BSC), upon the strategy process. Recently, it has been suggested that as a strategy tool, the BSC can influence all elements of the strategy process. The results of this study indicate that although there are significant differences in some elements of the strategy process between the organisations that have implemented the BSC and those that have not, the impact is not comprehensive. © 2011 Operational Research Society Ltd. All rights reserved.

The impact of phase conjugation on the nonlinear-Shannon limit:the difference between optical and electrical phase conjugation

We show that optical and electrical phase conjugation enable effective nonlinear compensation, The impact of polarization mode dispersion and finite processing bandwidth on the ultimate limits are also considered.

Uncovering the root cause of ethnic difference in ability testing:differential test functioning, test familiarity and trait optimism as explanations of ethnic group differences

The present research represents a coherent approach to understanding the root causes of ethnic group differences in ability test performance. Two studies were conducted, each of which was designed to address a key knowledge gap in the ethnic bias literature. In Study 1, both the LR Method of Differential Item Functioning (DIF) detection and Mixture Latent Variable Modelling were used to investigate the degree to which Differential Test Functioning (DTF) could explain ethnic group test performance differences in a large, previously unpublished dataset. Though mean test score differences were observed between a number of ethnic groups, neither technique was able to identify ethnic DTF. This calls into question the practical application of DTF to understanding these group differences. Study 2 investigated whether a number of non-cognitive factors might explain ethnic group test performance differences on a variety of ability tests. Two factors – test familiarity and trait optimism – were able to explain a large proportion of ethnic group test score differences. Furthermore, test familiarity was found to mediate the relationship between socio-economic factors – particularly participant educational level and familial social status – and test performance, suggesting that test familiarity develops over time through the mechanism of exposure to ability testing in other contexts. These findings represent a substantial contribution to the field’s understanding of two key issues surrounding ethnic test performance differences. The author calls for a new line of research into these performance facilitating and debilitating factors, before recommendations are offered for practitioners to ensure fairer deployment of ability testing in high-stakes selection processes.

Az európai uniós támogatások hatékonysága és hatásossága közötti különbség a ROP 1.2 intézkedésnél (The difference between the efficiency and effectiveness of using the EU-subsidies at Regional Operational Program)

A szerző cikkében megpróbál rávilágítani annak fontosságára, hogy az Európai Unióból érkező fejlesztési támogatások hasznosulása és a támogatási rendszer hatékonysága között jelentős különbség van. Ha nem tudjuk hatékonyan és hatásosan felhasználni az Unióból érkező pénzügyi eszközöket, akkor a cél: a kohézió, a konvergencia az Európai Unió régi tagállamainak fejlettségi szintjéhez, jólétéhez még nehezebben és lassabban érhető el. Az uniós támogatások hatékonysága alapvetően a rendelkezésre álló pénz lekötésének, lehívásának arányából, illetve a lekötött, lehívott és esetleg visszafizetett összeg arányából állapítható meg (kvantitatív megközelítés). A támogatások felhasználásának hatékonyságánál bonyolultabb, jóval összetettebb megközelítést igényel a hatásosság fogalma. A felhasználás hatásosságát a projektszinten a támogatás hatására megtermelt hozzáadott értékkel, programszinten a GDP hozzáadott növekedéssel lehet kifejezni. A cikk alapvetően a ROP 1.2 "Turisztikai fogadóképesség javítása" pályázati kiírás nyertes projektjeinél végzett kutatás eredményein keresztül kívánja szemléltetni a projektszintű vagy mikro hatásosság fontosságára (kvalitatív megközelítés). _________ The author tries to highlight the importance the difference between the efficiency and effectiveness of using the EU-subsidies. If Hungary cannot use the financial means of the EU efficiently and effectively, than the goal: cohesion and convergence to the level of the old, developed countries of the EU will be much harder and slowly. The efficiency of the EU-subsidies can be measured by the ratio of the amount of money obliged and the amount of money spent, and by the amount of money withdrawn by the Commission, which is actually lost (quantitative approach). The effectiveness of EU-subsidies needs a much more complicated and complex approach, than the efficiency. The effectiveness of usage on project level can be measured by the "added value" of the project, on program level by the added GDP growth or employment. The article is analysing basically the results of a survey made among the winner project of the application ROP 1.2 (Regional Operational Program 1.2) Improving the capacity for tourism (project level or micro effectiveness – qualitative approach).