8,048 research outputs found
Open educational practices for curriculum enhancement
Open educational resources (OER) and open educational practices (OEP) are relatively new areas in educational research. How OER and OEP can help practitioners enhance curricula is one of a number of under-researched topics. This article aims to enable practitioners to identify and implement appropriate open practices to enhance higher education curricula. To that aim, we put forward a framework of four open educational practices based on patterns of OER reuse (‘as is’ or adapted), mapped against the processes of curriculum design and delivery. The framework was developed from the in-depth analysis of 20 cases of higher education practitioners, which revealed patterns of OER reuse across disciplines, institutions and needs. For each open practice we offer evidence, examples and ideas for application by practitioners. We also put forward recommendations for institutional policies on OER and OE
Observation of Droplet Size Oscillations in a Two-Phase Fluid under Shear Flow
Experimental observations of droplet size sustained oscillations are reported
in a two-phase flow between a lamellar and a sponge phase. Under shear flow,
this system presents two different steady states made of monodisperse
multilamellar droplets, separated by a shear-thinning transition. At low and
high shear rates, the droplet size results from a balance between surface
tension and viscous stress whereas for intermediate shear rates, it becomes a
periodic function of time. A possible mechanism for such kind of oscillations
is discussed
3D printing dimensional calibration shape: Clebsch Cubic
3D printing and other layer manufacturing processes are challenged by
dimensional accuracy. Several techniques are used to validate and calibrate
dimensional accuracy through the complete building envelope. The validation
process involves the growing and measuring of a shape with known parameters.
The measured result is compared with the intended digital model. Processes with
the risk of deformation after time or post processing may find this technique
beneficial. We propose to use objects from algebraic geometry as test shapes. A
cubic surface is given as the zero set of a 3rd degree polynomial with 3
variables. A class of cubics in real 3D space contains exactly 27 real lines.
We provide a library for the computer algebra system Singular which, from 6
given points in the plane, constructs a cubic and the lines on it. A surface
shape derived from a cubic offers simplicity to the dimensional comparison
process, in that the straight lines and many other features can be analytically
determined and easily measured using non-digital equipment. For example, the
surface contains so-called Eckardt points, in each of which three of the lines
intersect, and also other intersection points of pairs of lines. Distances
between these intersection points can easily be measured, since the points are
connected by straight lines. At all intersection points of lines, angles can be
verified. Hence, many features distributed over the build volume are known
analytically, and can be used for the validation process. Due to the thin shape
geometry the material required to produce an algebraic surface is minimal. This
paper is the first in a series that proposes the process chain to first define
a cubic with a configuration of lines in a given print volume and then to
develop the point cloud for the final manufacturing. Simple measuring
techniques are recommended.Comment: 8 pages, 1 figure, 1 tabl
A Parallel Tree code for large Nbody simulation: dynamic load balance and data distribution on CRAY T3D system
N-body algorithms for long-range unscreened interactions like gravity belong
to a class of highly irregular problems whose optimal solution is a challenging
task for present-day massively parallel computers. In this paper we describe a
strategy for optimal memory and work distribution which we have applied to our
parallel implementation of the Barnes & Hut (1986) recursive tree scheme on a
Cray T3D using the CRAFT programming environment. We have performed a series of
tests to find an " optimal data distribution " in the T3D memory, and to
identify a strategy for the " Dynamic Load Balance " in order to obtain good
performances when running large simulations (more than 10 million particles).
The results of tests show that the step duration depends on two main factors:
the data locality and the T3D network contention. Increasing data locality we
are able to minimize the step duration if the closest bodies (direct
interaction) tend to be located in the same PE local memory (contiguous block
subdivison, high granularity), whereas the tree properties have a fine grain
distribution. In a very large simulation, due to network contention, an
unbalanced load arises. To remedy this we have devised an automatic work
redistribution mechanism which provided a good Dynamic Load Balance at the
price of an insignificant overhead.Comment: 16 pages with 11 figures included, (Latex, elsart.style). Accepted by
Computer Physics Communication
Effects of a multi-component exercise program and calcium–vitamin-D3-fortified milk on bone mineral density in older men : a randomised controlled trial
Summary We examined the independent and combined effects of a multi-component exercise program and calcium–vitamin-D3-fortified milk on bone mineral density (BMD) in older men. Exercise resulted in a 1.8% net gain in femoral neck BMD, but additional calcium–vitamin D3 did not enhance the response in this group of older well-nourished men.Introduction This 12-month randomised controlled trial assessed whether calcium–vitamin-D3-fortified milk could enhance the effects of a multi-component exercise program on BMD in older men.Methods Men (n  = 180) aged 50–79 years were randomised into: (1) exercise + fortified milk; (2) exercise; (3) fortified milk; or (4) controls. Exercise consisted of high intensity progressive resistance training with weight-bearing impact exercise. Men assigned to fortified milk consumed 400 mL/day of low fat milk providing an additional 1,000 mg/day calcium and 800 IU/day vitamin D3. Femoral neck (FN), total hip, lumbar spine and trochanter BMD and body composition (DXA), muscle strength 25-hydroxyvitamin D and parathyroid hormone (PTH) were assessed.Results There were no exercise-by-fortified milk interactions at any skeletal site. Exercise resulted in a 1.8% net gain in FN BMD relative to no-exercise (p < 0.001); lean mass (0.6 kg, p < 0.05) and muscle strength (20–52%, p < 0.001) also increased in response to exercise. For lumbar spine BMD, there was a net 1.4–1.5% increase in all treatment groups relative to controls (all p < 0.01). There were no main effects of fortified milk at any skeletal site.Conclusion A multi-component community-based exercise program was effective for increasing FN BMD in older men, but additional calcium–vitamin D3 did not enhance the osteogenic response.<br /
Shear-banding in a lyotropic lamellar phase, Part 2: Temporal fluctuations
We analyze the temporal fluctuations of the flow field associated to a
shear-induced transition in a lyotropic lamellar phase: the layering transition
of the onion texture. In the first part of this work [Salmon et al., submitted
to Phys. Rev. E], we have evidenced banded flows at the onset of this
shear-induced transition which are well accounted for by the classical picture
of shear-banding. In the present paper, we focus on the temporal fluctuations
of the flow field recorded in the coexistence domain. These striking dynamics
are very slow (100--1000s) and cannot be due to external mechanical noise.
Using velocimetry coupled to structural measurements, we show that these
fluctuations are due to a motion of the interface separating the two
differently sheared bands. Such a motion seems to be governed by the
fluctuations of , the local stress at the interface between the
two bands. Our results thus provide more evidence for the relevance of the
classical mechanical approach of shear-banding even if the mechanism leading to
the fluctuations of remains unclear
Public Health Care Delivery in Five U.S. Municipalities: Lessons and Implications
Increasing pressures on private and public hospitals have necessitated a reassessment of urban health care delivery. Patients left unserved by stressed private hospitals have placed a greater burden on public institutions, which themselves are often old, underfunded, and in danger of closure. As policy analysts consider remedies, primary care in community-based settings has reemerged as an important component of planning. We present results of a comparative analysis of five public health care delivery systems (Boston, Dallas, Denver, Milwaukee, and Seattle), reflecting their economic, political, and cultural dynamics. Although significant differences in the relative centralization of care and reliance on community-based clinics are evident, the five cities discussed have incorporated an increased emphasis on preventive and primary care. The diversity among the systems is highlighted: adaptability is apparently a vital component in designing a public health care system appropriate to the needs of particular communities. Implications for Chicago and other cities are discussed
Visualizing elements of Sha[3] in genus 2 jacobians
Mazur proved that any element xi of order three in the Shafarevich-Tate group
of an elliptic curve E over a number field k can be made visible in an abelian
surface A in the sense that xi lies in the kernel of the natural homomorphism
between the cohomology groups H^1(k,E) -> H^1(k,A). However, the abelian
surface in Mazur's construction is almost never a jacobian of a genus 2 curve.
In this paper we show that any element of order three in the Shafarevich-Tate
group of an elliptic curve over a number field can be visualized in the
jacobians of a genus 2 curve. Moreover, we describe how to get explicit models
of the genus 2 curves involved.Comment: 12 page
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