Spatialising the scholarly imagination: Globalisation, refugees and education

The notion of globalisation has attracted much attention since its arrival as a master concept in the social science disciplines in the 1990s. Despite the flurry of commentary, much work remains to be done. One of the consequences of the emphasis on the newness and uniqueness of globalisation is a tendency to view established disciplines and intellectual traditions as ‘old fashioned’ or ‘outdated’ (Robinson, 2003, Eriksen, 2003). This, we suggest, is a problematic view. We use the case of refugees to argue that talk about a borderless world and global connectivity is misleading as ‘old’ ontologies of space, time and identity are still at work

Cooling Performance of a Novel Circulatory Flow Concentric Multi-Channel Heat Sink with Nanofluids

Heat rejection from electronic devices such as processors necessitates a high heat removal rate. The present study focuses on liquid-cooled novel heat sink geometry made from four channels (width 4 mm and depth 3.5 mm) configured in a concentric shape with alternate flow passages (slot of 3 mm gap). In this study, the cooling performance of the heat sink was tested under simulated controlled conditions.The lower bottom surface of the heat sink was heated at a constant heat flux condition based on dissipated power of 50 W and 70 W. The computations were carried out for different volume fractions of nanoparticles, namely 0.5% to 5%, and water as base fluid at a flow rate of 30 to 180 mL/min. The results showed a higher rate of heat rejection from the nanofluid cooled heat sink compared with water. The enhancement in performance was analyzed with the help of a temperature difference of nanofluid outlet temperature and water outlet temperature under similar operating conditions. The enhancement was ~2% for 0.5% volume fraction nanofluids and ~17% for a 5% volume fraction

Influence of solvent molecular geometry on the growth of nanostructures

Solvent properties such as surface tension, dielectric constant, and viscosity have been extensively studied over more than 150 years to understand their influence on the growth kinetics of nanostructures. Interestingly, these nanoparticles-based studies have missed the influence of solvent molecular geometry. Herein, by synthesizing ZnO nanorods on a highly conductive nitrogen incorporated graphene oxide (N-GO) substrate, we present the first study showing the influence of solvent molecular geometry on the growth mechanism of nanostructures. The solvents such as water (N-GO-ZnO-W) allow a large number of functional atoms along a, b and c-axis to coordinate in all possible directions with the metal ions of wurtzite hexagonal crystal system of ZnO and thus leads to lower aspect ratio nanorods. On the contrary, the unavailability of binding sites along a-axis for solvents such as ethanol (N-GO-ZnO-E) provides a size-limiting effect and leads to preferred growth along b and c-axis, thus generating ZnO nanorods with a higher aspect ratio. The study shows that the number of interacting atoms, carbon chain length and the solvent molecular geometry influence the aspect ratio and therefore a solvent could be used to tune the nanostructures morphology and hence the performance of devices based on them

van der Waals contact engineering of graphene field-effect transistors for large-area flexible electronics

Graphene has great potential for high-performance flexible electronics. Although studied for more than a decade, contacting graphene efficiently, especially for large-area, flexible electronics, is still a challenge. Here, by engineering the graphene-metal van der Waals (vdW) contact, we demonstrate that ultra-low contact resistance is achievable via a bottom-contact strategy incorporating a simple transfer process without any harsh thermal treatment (>150°C). The majority of the fabricated devices show contact resistances below 200 Ω·µm with values as low as 65 Ω·µm achievable. This is on a par with the state-of-the-art top- and edge-contacted graphene field-effect transistors (GFETs). Further, our study reveals that these contacts, despite the presumed weak nature of the vdW interaction, are stable under various bending conditions, thus guaranteeing compatibility with flexible electronics with improved performance. This work illustrates the potential of the previously underestimated vdW contact approach for large-area flexible electronics

Computationally-predicted CB1 cannabinoid receptor mutants show distinct patterns of salt-bridges that correlate with their level of constitutive activity reflected in G protein coupling levels, thermal stability, and ligand binding

The cannabinoid receptor 1 (CB1), a member of the class A G-protein-coupled receptor (GPCR) family, possesses an observable level of constitutive activity. Its activation mechanism, however, has yet to be elucidated. Previously we discovered dramatic changes in CB1 activity due to single mutations; T3.46A, which made the receptor inactive, and T3.46I and L3.43A, which made it essentially fully constitutively active. Our subsequent prediction of the structures of these mutant receptors indicated that these changes in activity are explained in terms of the pattern of salt-bridges in the receptor region involving transmembrane domains 2, 3, 5, and 6. Here we identified key salt-bridges, R2.37 + D6.30 and D2.63 + K3.28, critical for CB1 inactive and active states, respectively, and generated new mutant receptors that we predicted would change CB1 activity by either precluding or promoting these interactions. We find that breaking the R2.37 + D6.30 salt-bridge resulted in substantial increase in G-protein coupling activity and reduced thermal stability relative to the wild-type reflecting the changes in constitutive activity from inactive to active. In contrast, breaking the D2.63 + K3.28 salt-bridge produced the opposite profile suggesting this interaction is critical for the receptor activation. Thus, we demonstrate an excellent correlation with the predicted pattern of key salt-bridges and experimental levels of activity and conformational flexibility. These results are also consistent with the extended ternary complex model with respect to shifts in agonist and inverse agonist affinity and provide a powerful framework for understanding the molecular basis for the multiple stages of CB1 activation and that of other GPCRs in general

Predicting the response of a submillimeter bolometer to cosmic rays

Bolometers designed to detect. submillimeter radiation also respond to cosmic, gamma, and x rays. Because detectors cannot be fully shielded from such energy sources, it is necessary to understand the effect of a photon or cosmic-ray particle being absorbed. The resulting signal (known as a glitch) can then be removed from raw data. We present measurements using an Americium-241 gamma radiation source to irradiate a prototype bolometer for the High Frequency Instrument in the Planck Surveyor satellite. Our measurements showed no variation in response depending on where the radiation was absorbed, demonstrating that the bolometer absorber and thermistor thermalize quickly. The bolometer has previously been fully characterized both electrically and optically. We find that using optically measured time constants underestimates the time taken for the detector to recover from a radiation absorption event. However, a full thermal model for the bolometer, with parameters taken from electrical and optical measurements, provides accurate time constants. Slight deviations from the model were seen at high energies; these can be accounted for by use of an extended model

Sustaining Viability of Informal Millet Seed Systems

The main purpose of alternative seed delivery system is to address the seed availability problems of smallholder farmers. Most of the community-based seed production models /schemes are initiated because farmers are concerned about the non-availability of quality seed at planting time. Many farmers don't have access to improved varieties; and wouldn't be able to afford them even if they were. So introduction of alternative seed systems models must impact farmers' access to seeds of improved varieties at affordable cost. The quality of seed produced by communitybased system or farmer seed systems is guaranteed only by its seller or village seed committee, because they are not processed and are uncertified seed. The seed so produced is low priced, and available at farmers' doorsteps at the right time, and provides access to all farmer groups in the village..

GEOLOCATION AWARE RESOURCE ALLOCATION IN CELLULAR BASED COGNITIVE RADIO NETWORKS WITH GREEN COMMUNICATION PERSPECTIVE

This paper puts forward a Geolocation aware spectrum and power allocation scheme for cellular-based cognitive radio network using the principle of sensing free spectrum access. The problem formulation to test the feasibility of deploying the secondary system within Terrestrial Trunked Radio (TETRA) based cellular primary system is carried out to maximize the served Secondary Users (SU) while keeping the interference to Primary Users (PU) under a predefined threshold. A novel model called Primary Mobility Contour (PMC) for the avoidance of harmful interference to PU is proposed, which will consider the velocity of PU, the time taken by the secondary base station for transmission and Geolocation information. Using this model sensing free spectrum and power allocation algorithm is developed for cellular-based cognitive radio network to maximize the served SU to enhance system throughput and achieve an enhanced energy efficiency of the system to attain green communication. Simulation results confirm that the proposed scheme maximizes the served SUs per cell, throughput and energy efficiency

Diversity of Lecidea (Lecideaceae, Ascomycota) species revealed by molecular data and morphological characters

The diversity of lichens, especially crustose species, in continental Antarctica is still poorly known. To overcome difficulties with the morphology based species delimitations in these groups, we employed molecular data (nuclear ITS and mitochondrial SSU rDNA sequences) to test species boundaries within the genus Lecidea. Sampling was done along a north–south transect at five different areas in the Ross Sea region (Cape Hallett, Botany Bay to Mount Suess, Taylor Valley, Darwin Area and Mount Kyffin). A total of 153 specimens were collected from 13 localities. Phylogenetic analyses also include specimens from other regions in Antarctica and non-Antarctic areas. Maximum parsimony, maximum likelihood and Bayesian analyses agreed in placing the samples from continental Antarctica into four major groups. Based on this phylogenetic estimate, we restudied the micromorphology and secondary chemistry of these four clades to evaluate the use of these characters as phylogenetic discriminators. These clades are identified as the following species Lecidea cancriformis, L. andersonii as well as the new species L. polypycnidophora Ruprecht & Türk sp. nov. and another previously unnamed clade of uncertain status, referred to as Lecidea sp. (L. UCR1)