Field Effect Transistors on Rubrene Single Crystals with Parylene Gate Insulator

We report on fabrication and characterization of the organic field effect transistors (OFETs) on the surface of single crystals of rubrene. The parylene polymer film has been used as the gate insulator. At room temperature, these OFETs exhibit the p-type conductivity with the field effect mobility up to 1 cm^2/Vs and the on/off ratio ~ 10^4. The temperature dependence of the mobility is discussed.Comment: 3 page

The impact of evolving labor practices and demographics on U.S. inflation and unemployment

Since the early 1990s, NAIRU estimates have declined and unemployment duration has risen relative to the unemployment rate. These developments may have arisen from the aging of the workforce or practices reducing job turnover. We assess the internal consistency of these hypotheses using simulation methods and test their external consistency using modified NAIRU models. We find that demographics cannot fully account for changes in the NAIRU, consistent with Staiger, Stock, and Watson (2001) and in contrast to Shimer (1998, 2001). Instead, our results attribute shifts in the NAIRU and duration to a combination of shifts in demographics and job turnover.

Sudden Expansion of a One-Dimensional Bose Gas from Power-Law Traps

We analyze free expansion of a trapped one-dimensional Bose gas after a sudden release from the confining trap potential. By using the stationary phase and local density approximations, we show that the long-time asymptotic density profile and the momentum distribution of the gas are determined by the initial distribution of Bethe rapidities (quasimomenta) and hence can be obtained from the solutions to the Lieb-Liniger equations in the thermodynamic limit. For expansion from a harmonic trap, and in the limits of very weak and very strong interactions, we recover the self-similar scaling solutions known from the hydrodynamic approach. For all other power-law traps and arbitrary interaction strengths, the expansion is not self-similar and shows strong dependence of the density profile evolution on the trap anharmonicity. We also characterize dynamical fermionization of the expanding cloud in terms of correlation functions describing phase and density fluctuations.Comment: Final published version with modified title and a couple of other minor changes. 5 pages, 2 figures, and Supplemental Materia

Editorial

Being asked to guest edit EECERJ has reinforced what I see as one of the great contributions of EECERA (through both its conferences and journal) – that of sharing ideas, practices, beliefs and theories on the care and education of young children. Any analysis of theoretical and empirical explorations of early childhood education illustrate that as a community there is a long history of sharing ideas on the care and education of young children (Georgeson et al. 2013; Miller and Cameron 2014). Sharing and comparing different approaches to early childhood education offers the advantage of helping to reveal what is taken for granted within our own cultures and opening up alternative possibilities (Tobin et al. 2009). However, despite the advantages of sharing ideas on the care and education of young children, the increased analysis of early education services by supra-national organisations risks ‘global panopticism’ (Lingard et al. 2013), whereby the global construction of early childhood education services acts a regulatory gaze as to the purpose of services and how they should be delivered and structured. The OECD’s proposed International Early Learning Study (IELS) is illustrative of the normative ways of thinking about early childhood education, whereby services are identified as a social good, supporting children’s lifelong learning (based on predefined desirable indicators) and offering early intervention to those from socio-economically disadvantaged circumstances (Moss et al. 2016). However, advocates of contextualised approaches to early childhood education would caution against a convergence of perspectives (Moss et al. 2016), identifying a need to appreciate that culture and history are central to explaining and understanding differences (Oberhuemer 2014; Tobin 2005; Tobin et al. 2009). Thus whilst considering the ‘other’ can offer alternative perspectives and open up new possibilities, the transfer of ideas may not always be possible or desirable

Translational perspectives on perfusion-diffusion mismatch in ischemic stroke

Magnetic resonance imaging has tremendous potential to illuminate ischemic stroke pathophysiology and guide rational treatment decisions. Clinical applications to date have been largely limited to trials. However, recent analyses of the major clinical studies have led to refinements in selection criteria and improved understanding of the potential implications for the risk vs. benefit of thrombolytic therapy. In parallel, preclinical studies have provided complementary information on the evolution of stroke that is difficult to obtain in humans due to the requirement for continuous or repeated imaging and pathological verification. We review the clinical and preclinical advances that have led to perfusion–diffusion mismatch being applied in phase 3 randomized trials and, potentially, future routine clinical practice

Questions of quality in repositories of open educational resources: a literature review

Open educational resources (OER) are teaching and learning materials which are freely available and openly licensed. Repositories of OER (ROER) are platforms that host and facilitate access to these resources. ROER should not just be designed to store this content – in keeping with the aims of the OER movement, they should support educators in embracing open educational practices (OEP) such as searching for and retrieving content that they will reuse, adapt or modify as needed, without economic barriers or copyright restrictions. This paper reviews key literature on OER and ROER, in order to understand the roles ROER are said or supposed to fulfil in relation to furthering the aims of the OER movement. Four themes which should shape repository design are identified, and the following 10 quality indicators (QI) for ROER effectiveness are discussed: featured resources; user evaluation tools; peer review; authorship of the resources; keywords of the resources; use of standardised metadata; multilingualism of the repositories; inclusion of social media tools; specification of the creative commons license; availability of the source code or original files. These QI form the basis of a method for the evaluation of ROER initiatives which, in concert with considerations of achievability and long-term sustainability, should assist in enhancement and development. Keywords: open educational resources; open access; open educational practice; repositories; quality assuranc

Three-dimensional Binary Superlattices of Oppositely-charged Colloids

We report the equilibrium self-assembly of binary crystals of oppositely-charged colloidal microspheres at high density. By varying the magnitude of the charge on near equal-sized spheres we show that the structure of the binary crystal may be switched between face-centered cubic, cesium chloride and sodium chloride. We interpret these transformations in terms of a competition between entropic and Coulombic forces