A Purely Functional Computer Algebra System Embedded in Haskell

We demonstrate how methods in Functional Programming can be used to implement a computer algebra system. As a proof-of-concept, we present the computational-algebra package. It is a computer algebra system implemented as an embedded domain-specific language in Haskell, a purely functional programming language. Utilising methods in functional programming and prominent features of Haskell, this library achieves safety, composability, and correctness at the same time. To demonstrate the advantages of our approach, we have implemented advanced Gr\"{o}bner basis algorithms, such as Faug\`{e}re's $F_4$ and $F_5$, in a composable way.Comment: 16 pages, Accepted to CASC 201

USDLA: An Instructional Media Selection Guide For Distance Learning

Purpose and Use of the Media Selection Guide Increasingly, educators and trainers are challenged within their respective organizations to provide for the efficient distribution of instructional con-tent using instructional media. The appropriate selection of instructional media to support distance learning is not intuitive and does not occur as a matter of personal preference. On the contrary, instructional media selec-tion is a systematic sequence of qualitative processes based on sound in-structional design principles. Although media selection is often mentioned when studying the discipline of instructional technology or Instructional Systems Design (ISD), it is sometimes overlooked when applying the se-lection process in a distance-learning environment. It is our intent, there-fore, for this guide to highlight the essentials of good media selection. We hope to present an instructionally sound and systematic approach to se-lecting the most appropriate media for the delivery of content at a dis-tance

Rescuing human development from a lip-service syndrome

Motivation : Despite widespread attention and praise from policy -makers, practitioners and individual academics for the Human Development Report, the paradigm of human development has often lacked sustained academic and operational policy -making attention . Purpose: Investigating this undesirable disconnect and discussing the possible reasons behind it, this article reveals two fundamental challenges: to make more specific the rich concepts of human development and to relate them to the dominant concepts of development globally an d to motivate and guide the context -specific choices made within national and regional contexts. Approach and Methods: Addressing these challenges will require a more careful exploration of the theoretical and operational implications of the work of Sen and Nussbaum as well as their adoption by the Human Development Report Office at the United Nations Development Programme (UNDP). Conclusions: To achieve this, the article makes some proposals both to UNDP and to academia for the future directions of this approach . Policy implications: The proposals seek to chart pathways out of the current economic stagnation and slowdown

HIV envelope tail truncation confers resistance to SERINC5 restriction

SERINCs and IFITMs are potent lentiviral restriction factors that inhibit infection by blocking viral entry into cells. Specifically, SERINCs inhibit viral fusion by targeting the envelope glycoprotein (Env) by a mechanism that remains incompletely understood. Here, we report that truncation of the Env cytoplasmic tail (CT) of HIV-1 and HIV-2 confers complete resistance to SERINC and IFITM restriction. Notably, while the EnvCT of HIV-1 is necessary for viral replication in T cells, HIV-2 does not require the EnvCT. Our data suggest a mechanism by which human lentiviruses can evade restriction that is mediated by the EnvCT but reveal key differences in the likely fitness cost imposed by this on pandemic HIV-1 and nonpandemic HIV-2

Reduction of blade-vortex interaction noise using higher harmonic pitch control

An acoustics test using an aeroelastically scaled rotor was conducted to examine the effectiveness of higher harmonic blade pitch control for the reduction of impulsive blade-vortex interaction (BVI) noise. A four-bladed, 110 in. diameter, articulated rotor model was tested in a heavy gas (Freon-12) medium in Langley's Transonic Dynamics Tunnel. Noise and vibration measurements were made for a range of matched flight conditions, where prescribed (open-loop) higher harmonic pitch was superimposed on the normal (baseline) collective and cyclic trim pitch. For the inflow-microphone noise measurements, advantage was taken of the reverberance in the hard walled tunnel by using a sound power determination approach. Initial findings from on-line data processing for three of the test microphones are reported for a 4/rev (4P) collective pitch control for a range of input amplitudes and phases. By comparing these results to corresponding baseline (no control) conditions, significant noise reductions (4 to 5 dB) were found for low-speed descent conditions, where helicopter BVI noise is most intense. For other rotor flight conditions, the overall noise was found to increase. All cases show increased vibration levels

Barriers and facilitators to hepatitis C treatment for people who inject drugs: A qualitative study

2012 Hepatitis C virus (HCV) infection is a significant global public health problem. The burden of HCV infection is concentrated among people who inject drugs (PWID), with an estimated five million PWID living with chronic HCV in the European Region. HCV antiviral treatment with peginterferon alfa and ribavirin is the standard care for chronic HCV, with a 50-85% cure rate depending on genotype. Research indicates that PWID are interested in HCV treatment uptake and have rates of viral clearance comparable with other populations. Current injectors are not precluded from HCV treatment access in a number of European countries, yet uptake rates are substandard

Simulation can offer a sustainable contribution to clinical education in osteopathy.

Background: Clinical education forms a substantial component of health professional education. Increased cohorts in Australian osteopathic education have led to consideration of alternatives to traditional placements to ensure adequate clinical exposure and learning opportunities. Simulated learning offers a new avenue for sustainable clinical education. The aim of the study was to explore whether directed observation of simulated scenarios, as part replacement of clinical hours, could provide an equivalent learning experience as measured by performance in an objective structured clinical examination (OSCE). Methods: The year 3 osteopathy cohort were invited to participate in replacement of 50% of their clinical placement hours with online facilitated, video-based simulation exercises (intervention). Competency was assessed by an OSCE at the end of the teaching period. Inferential statistics were used to explore any differences between the control and intervention groups as a post-test control design. Results: The funding model allowed ten learners to participate in the intervention, with sixty-six in the control group. Only one OSCE item was significantly different between groups, that being technique selection (p = 0.038, d = 0.72) in favour of the intervention group, although this may be a type 1 error. Grade point average was moderately positively correlated with the manual therapy technique station total score (r = 0.35, p < 0.01) and a trivial relationship with the treatment reasoning station total score (r = 0.17, p = 0.132). Conclusions: The current study provides support for further investigation into part replacement of clinical placements with directed observation of simulated scenarios in osteopathy

Demonstration of the Zero-Crossing Phasemeter with a LISA Test-bed Interferometer

The Laser Interferometer Space Antenna (LISA) is being designed to detect and study in detail gravitational waves from sources throughout the Universe such as massive black hole binaries. The conceptual formulation of the LISA space-borne gravitational wave detector is now well developed. The interferometric measurements between the sciencecraft remain one of the most important technological and scientific design areas for the mission. Our work has concentrated on developing the interferometric technologies to create a LISA-like optical signal and to measure the phase of that signal using commercially available instruments. One of the most important goals of this research is to demonstrate the LISA phase timing and phase reconstruction for a LISA-like fringe signal, in the case of a high fringe rate and a low signal level. We present current results of a test-bed interferometer designed to produce an optical LISA-like fringe signal previously discussed in the literature.Comment: find minor corrections in the CQG versio

Surface Defect Mitigation of Additively Manufactured Parts Using Surfactant-Mediated Electroless Nickel Coatings

The emergence of defects during the early production phases of ferrous-alloy additively manufactured (AM) parts poses a serious threat to their versatility and adversely impacts their overall mechanical performance in industries ranging from aerospace engineering to medicine. Lack of fusion and gas entrapment during the manufacturing stages leads to increased surface roughness and porosities in the finished part. In this study, the efficacy of employing electroless nickel–boron (Ni-B) deposition to fill and level simulated AM defects was evaluated. The approach to levelling was inspired by the electrochemical deposition techniques used to fill vias in the electronics industry that (to some extent) resemble the size and shape of AM-type defects. This work investigated the use of surfactants to attenuate surface roughness in electroless nickel coatings, thereby achieving the preferential inhibition of the coating thickness on the surface and promoting the filling of the simulated defects. A cationic surfactant molecule, CTAB (cetyltrimethyl ammonium bromide), and a nonpolar surfactant, PEG (polyethylene glycol), at different concentrations were tested using a Ni-B electrolyte for the levelling study. It was found that the use of electroless Ni-B to fill simulated defects on ferrous alloys was strongly influenced by the concentration and nature of the surfactant. The highest levelling percentages were obtained for the heavy-molecular-weight PEG-mediated coatings at 1.2 g/L. The results suggest that electroless Ni-B deposition could be a novel and facile approach to filling defects in ferrous-based AM parts