21 research outputs found
The International Patent System and Biomedical Research: Reconciling Aspiration, Policy and Practice
This article reviews how the international environment shapes international patent law and practice with bearing on biomedical innovation. The cluster of issues is encapsulated in two core paradoxes. The first concerns how public goods, such as new pharmaceuticals, may be produced through the deliberate creation of private rights that exclude material from the public domain. The second paradox concerns how “technological neutrality” and overall policy balance in the application of general patent law principles requires technology-specific interventions by regulators. The article illustrates how centrifugal and centripetal trends influence diverse national approaches to applying patentability criteria for pharmaceutical products
Deformation bands and the formation of grain boundaries in a superplastic aluminum alloy
Superplastic aluminum alloys are often classified according to the mechanism of microstructural
transformation during annealing after deformation processing. In Al-Cu-Zr materials, such as Supral
2004, the presence of fine (10 to 50 nm) second-phase particles retards dislocation rearrangement
and the formation and migration of boundaries during either annealing or elevated temperature
deformation after thermomechanical processing. This leads to predominance of recovery in the evolution of microstructure, although high-angle boundaries must still form in order to account for the
superplastic response of such materials. The mechanisms of high-angle boundary formation in such
circumstances have remained unclear. The term “continuous recrystallization” (CRX) has been used as
a phenomenological description of recovery-dominated processes that take place uniformly through-
out the microstructure and lead to the formation of fine grains with high-angle boundaries.
Orientation imaging microscopy (OIM) methods have been employed to assess the as-processed
microstructure of this alloy and its evolution during annealing at 450 °C, as well as during
superplastic deformation at this temperature. Orientation images demonstrate the presence of
deformation bands of alternating lattice orientations that corresponds to the symmetric variants of
the brass, or B, texture component ((112){110} in rolled material). During annealing, the
high-angle grain boundaries (disorientation of 50 to 62.8 deg) develop from transition regions
between such bands while the lower-angle boundaries (i.e., up to 20 deg) separate an evolving cell
structure within the bands. Further OIM results show that the bands remain distinct features of the
microstructure during either annealing alone or during deformation under superplastic conditions
The impact of tandem redundant/sky-based calibration in MWA Phase II data analysis
Precise instrumental calibration is of crucial importance to 21-cm cosmology experiments. The Murchison Widefield Array's (MWA) Phase II compact configuration offers us opportunities for both redundant calibration and sky-based calibration algorithms; using the two in tandem is a potential approach to mitigate calibration errors caused by inaccurate sky models. The MWA Epoch of Reionization (EoR) experiment targets three patches of the sky (dubbed EoR0, EoR1, and EoR2) with deep observations. Previous work in Li et al. (2018) and (2019) studied the effect of tandem calibration on the EoR0 field and found that it yielded no significant improvement in the power spectrum (PS) over sky-based calibration alone. In this work, we apply similar techniques to the EoR1 field and find a distinct result: The improvements in the PS from tandem calibration are significant. To understand this result, we analyse both the calibration solutions themselves and the effects on the PS over three nights of EoR1 observations. We conclude that the presence of the bright radio galaxy Fornax A in EoR1 degrades the performance of sky-based calibration, which in turn enables redundant calibration to have a larger impact. These results suggest that redundant calibration can indeed mitigate some level of model incompleteness error