6,505 research outputs found
Monetary and Exchange Rate Policy Coordination in ASEAN 1
This paper develops the basis for monetary and exchange rate coordination in Asia as part of a package of monetary integration that could support growth and poverty reduction. This could be achieved directly through coordinated exchange rate stabilization, and indirectly through the implications of this for reserve pooling and investment in an Asian development fund (ADF) and through development of the Asian bond market (ABM). Macro policy coordination could be viewed as a necessary condition for further development of both reserve pooling via the Chiang Mai Initiative (CMI) and of the ABM. The paper analyzes the trade structure of ASEAN and China in terms of both geographic sources of imports and markets for exports, and of the commodity structure of trade. The similarities of the geographic and commodity trade structures across the region are consistent with adoption of a common currency basket for stabilization, and with an argument for monetary integration across the region along the lines of Mundell (1961) on optimum currency areas. The paper constructs currency baskets and real effective exchange rates (REERs) for the countries in the region. Since their trade patterns are quite similar and their policies are already implicitly coordinated, their REERs tend to move together. This means that ASEAN and China are already moving toward integration in practical effect. Explicit movement toward coordination could support surveillance and reserve-sharing under the CMI, and release reserves to be invested in an ADF.
Semiconductor filled microstructured optical fibres with single mode guidance
Microstructured optical fibre (MOF) technology has generated new opportunities for the implementation of optical fibres with novel properties and functions [1]. It has been shown that silica MOFs make excellent 3D templates for semiconductor material deposition inside the capillary voids [2]. Recently a silicon MOF was designed and fabricated that had a high refractive index micron sized core, but yet only supported two guided modes [3]. This structure was realised via the complete filling of a hollow core photonic bandgap fibre (PBGF) with silicon so that the original air guiding PBGF was converted to a total internal reflection guiding fibre. Here, we extend the investigation by using a finite element method to model the optical properties of semiconductor filled MOFs of similar structures, with the aim to achieve broadband single mode guidance. Strategies to achieve single mode guidance both through the MOF template design and the selective filling of the voids of the original PBGF with semiconductor materials of different indices (silicon, silicon nitride, germanium) are proposed and investigated numerically. In particular, by selectively filling MOF templates with cladding rods that have a slightly raised index over that of the core, index guiding single mode operation can be observed in high index micron sized cores. Small index differences are achievable by controlling the nitrogen content in SiNx and an example of a single mode semiconductor MOF is shown in Figure 1, where the confinement loss of the fundamental mode is ~106 lower than the lowest order cladding mode
Erodibility of hill peat
peer-reviewedThe project was funded by the European Union Structural Funds EAGGF distributed under the Department of Agriculture and Food Stimulus Fund.The energy necessary to entrain soil in water depends on the soil strength. Once entrained, the settling velocity of the eroded soil in water is of fundamental importance to the processes of sediment transport and deposition. In this paper, stream power theory and transport concepts coupled with the equation of continuity were used to derive a transport-limited peat concentration. The ratio of the log of the actual sediment concentration in surface run-off to the log of the transport-limited sediment concentration was the index of erosion used. The value of this index is a measure of the sensitivity of peat to erosion by sheet flow. Four peats were subjected to a range of overland flow rates under two slopes in a laboratory flume. The peats represented peat farmed in a sustainable manner (Leenane), overgrazed peat (Maam), peat undergoing erosion (Newport) and peat which had undergone weathering following exposure by a landslip (Croagh Patrick). Both in situ and surface damaged slabs were studied. The results indicate that shearing and remoulding of a wet peat surface (e.g., by animal treading) and weathering of exposed drained peat surfaces predispose peat to erosion. Defoliation by overgrazing is considered to be of secondary importance.Department of Agriculture, Food and the MarineEuropean Union Structural Funds EAGG
Ultrafast optical control using the Kerr nonlinearity in hydrogenated amorphous silicon microcylindrical resonators
Microresonators are ideal systems for probing nonlinear phenomena at low thresholds due to their small mode volumes and high quality (Q) factors. As such, they have found use both for fundamental studies of light-matter interactions as well as for applications in areas ranging from telecommunications to medicine. In particular, semiconductor-based resonators with large Kerr nonlinearities have great potential for high speed, low power all-optical processing. Here we present experiments to characterize the size of the Kerr induced resonance wavelength shifting in a hydrogenated amorphous silicon resonator and demonstrate its potential for ultrafast all-optical modulation and switching. Large wavelength shifts are observed for low pump powers due to the high nonlinearity of the amorphous silicon material and the strong mode confinement in the microcylindrical resonator. The threshold energy for switching is less than a picojoule, representing a significant step towards advantageous low power silicon-based photonic technologies
A LEAKY INTEGRATE-AND-FIRE NEURON WITH ADJUSTABLE REFRACTORY PERIOD AND SPIKE FREQUENCY ADAPTATION
As standard CMOS technology approaches its physical limitations there is increased motivation to explore new computing paradigms. One possible path forward is to develop an array of computational architectures which specialize in distinct tasks. Neural computing architectures excel at pattern recognition and processing low-fidelity sensory input, but one of the biggest challenges in the field has been implementing architectures which strike an appropriate balance between biologically-plausible performance and the simplicity needed to make large neural systems practical. This work proposes a new VLSI neural architecture which seeks to provide such a balance.
The design described here builds on an implementation first proposed by van Schaik. Van Schaik’s circuit has the advantage of simplicity. It uses a Leaky-Integrate-and-Fire model while offering some biologically analogous behavior and maintaining a very compact layout profile. However, the circuit lacks the ability to emulate certain desirable biologically inspired features, most notably spike frequency adaptation (SFA).
The circuit depicted receives a current stimulus as its input. If the current is greater than the neuron’s leakage current, then it charges a capacitor which drives a comparator circuit. When the voltage on the capacitor exceeds the threshold voltage a spike is generated. The design makes use of four parametric inputs to tune its behavior and also contains circuitry for a tunable refractory period and SFA.
Rather than operate in biological time, the circuit operates in accelerated time with a spike frequency in the nano-second region. This allows smaller capacitors to be used and reduces the overall layout area. The circuit layout was created using Tanner EDA’s L-Edit software and designed for fabrication with a 180nm technology node. It occupies 386.497µm2. The circuit was extracted and simulated using Tanner Tools T-Spice. Simulations show an average power consumption in the micro-Watt range
Adolescents' and parents' views of Child and Adolescent Mental Health Services (CAMHS) in Ireland
Aim: To explore adolescents’ and parents’ experiences of CAMHS in relation to accessibility, approachability, and appropriateness. Methods: Using a descriptive qualitative design, a combination of focus group and single interviews were conducted with adolescents (n=15) and parents (n=32) from three mental health clinics. Data were transcribed verbatim and analysed using thematic analysis. Results: Accessing mental health services was a challenging experience due to knowledge deficit, lack of information and limited availability of specialist services. Participants desired more information, involvement in decision-making, single and shared consultations, flexible scheduling of appointments, continuity with clinicians, school support and parent support groups. Participants seem to be generally satisfied, however adolescents felt less involved in decision making than they would have liked. Frequent staff changes was problematic as it disrupted continuity of care and hindered the formation of a trusting relationship. Implications for practice: Parents and adolescents expressed similar views of the positive and negative aspects of mental health services. Their need for more information-sharing and involvement in decision-making underline the importance of collaborative practice. Clinician continuity contributed to trusting therapeutic relationships and was valued. These are key principles that with attention, could lead to quality service provision for adolescents and families
Real-world geographers and geography students using GIS: relevance, everyday applications and the development of geographical knowledge
While Geographical information systems (GIS) are increasingly being seen in school geography classrooms, there remains significant reluctance among teachers to engage with the technology (e.g. Hong, 2017), as well as limited consideration of students’ perspectives on GIS. In response to this, we have undertaken research to explore how a programme of GIS training, integrated within a two-year A-Level examination course, develops students’ perceptions of the value and nature of GIS, their subsequent engagement with it, and its impact on their geographical knowledge. This paper reports on one strand of the longitudinal research which focuses on how tapping into the expertise of real-world, industry experts can affect students’ perceptions of the relevance of GIS to geography and support their acquisition of geographical knowledge. The project, an interpretive case study, used questionnaires, interviews and analysis of students’ work to elicit students’ developing perceptions of and engagement with GIS, as well as changes in their geographical knowledge. Results suggest that engagement with industry experts aids students’ understanding of what GIS is, allowing them to develop a more nuanced appreciation of its real-world applications; this then appears to play both a direct and indirect role in the subsequent development of students’ geographical knowledg
Sitting and chronic disease: where do we go from here?
KW is supported by a British Heart Foundation Intermediate Basic Science Research Fellowship (grant number FS/12/58/29709) and the UK Medical Research Council (grant number MC_UU_12015/3). GNH is supported by an Australian National Health and Medical Research Council Career Development Fellowship (grant number 108029).This is the author accepted manuscript. The final version is available from Springer via http://dx.doi.org/10.1007/s00125-016-3886-
Does diet mediate associations of volume and bouts of sedentary time with cardiometabolic health indicators in adolescents?
Objective: Examine the mediating role of diet in the relationship between volume and duration of sedentary time with cardiometabolic health in adolescents. Methods: Adolescents (12-19 years) participating in the 2003/04 and 2005/06 U.S. National Health and Nutrition Examination Survey (NHANES) were examined. Cardiometabolic health indicators were body mass index z-scores (zBMI) (n 5 1,797) and metabolic syndrome (MetS) (n 5 812). An ActiGraph hip-worn accelerometer was used to derive total sedentary time and usual sedentary bout duration. Dietary intake was assessed using two 24-hour dietary recalls. Mediation analyses were conducted to examine five dietary mediators [total energy intake, discretionary foods, sugar-sweetened beverages (SSB), fruits and vegetables, and dietary quality] of the relationship between total sedentary time and usual sedentary bout duration with zBMI and MetS. Results: Total sedentary time was inversely associated with zBMI (b 5 21.33; 95% CI 22.53 to 20.13) but attenuated after adjusting for moderate-to-vigorous physical activity. No significant associations were observed between usual sedentary bout duration with zBMI or either sedentary measure with MetS. None of the five dietary variables mediated any of the relationships examined. Conclusions: Further studies are needed to explore associations of specific time periods (e.g., after school) and bout durations with both cardiometabolic health indicators and dietary behaviors
Mid-infrared transmission properties of step index and large mode area ZnSe microstructured optical fibers
ZnSe microstructured fibers have been designed and fabricated using silica capillaries and an air-silica photonic band-gap optical fiber as high-pressure microfluidic templates for semiconductor growth via chemical fluid deposition. We examine their transmission properties over a wide spectral range
- …