21,955 research outputs found
Polymer micro-grippers with an integrated force sensor for biological manipulation
The development of a novel micro-system integrating SU-8 polymer micro-grippers with a tensile force sensor for handling and characterizing the mechanical properties of delicate biological materials, such as fibrils, is presented. The micro-grippers are actuated by the electro-thermal effect and have gripping forces comparable to the common \u27hot-and-cold-arm\u27 grippers. A robust finite element model was developed to investigate system performance and validated experimentally. A new micro-mechanical calibration method using a piezoelectric manipulator with a micro-force measurement system was successfully applied to test the structure. Both FEA simulation and micro-mechanical testing results indicated that the system could fulfil the requirements for micro-object manipulation within a biological environment
Delivering public services in the mixed economy of welfare : perspectives from the voluntary and community sector in rural England
The voluntary and community sector in England is playing an increasingly important role in the delivery of public services to older adults and in doing so they rely on unpaid volunteers. In this article, we draw on the findings of a recent qualitative study of the impact on the voluntary and community sector of delivering ‘low-level’ public services that promote independent living and wellbeing in old age. The fieldwork focused on services that help older adults aged 70+ living in remote rural communities across three English regions. Those charged with service delivery, which is increasingly the voluntary and community sector, face particular challenges, such as uncertain funding regimes and reliance on volunteer labour
Endogenous growth and property rights over renewable resources
We study how different regimes of access rights to renewable natural resources - namely, open access versus full property rights – affect sustainability, growth and welfare in the context of modern endogenous growth theory. Resource exhaustion may occur under both regimes but is more likely to arise under open access. Moreover, under full property rights, positive resource rents increase expenditures on manufacturing goods and temporarily accelerate productivity growth, but also yield a higher resource price at least in the short-to-medium run. We characterize analytically and quantitatively the model’s dynamics to assess the welfare implications of differences in property rights enforcement
Deep structure of the Baringo Rift Basin (central Kenya) from three-dimensional magnetotelluric imaging: Implications for rift evolution
Evidence of Titan's Climate History from Evaporite Distribution
Water-ice-poor, 5-m-bright material on Saturn's moon Titan has
previously been geomorphologically identified as evaporitic. Here we present a
global distribution of the occurrences of the 5-m-bright spectral unit,
identified with Cassini's Visual Infrared Mapping Spectrometer (VIMS) and
examined with RADAR when possible. We explore the possibility that each of
these occurrences are evaporite deposits. The 5-m-bright material covers
1\% of Titan's surface and is not limited to the poles (the only regions with
extensive, long-lived surface liquid). We find the greatest areal concentration
to be in the equatorial basins Tui Regio and Hotei Regio. Our interpretations,
based on the correlation between 5-m-bright material and lakebeds, imply
that there was enough liquid present at some time to create the observed
5-m-bright material. We address the climate implications surrounding a
lack of evaporitic material at the south polar basins: if the south pole basins
were filled at some point in the past, then where is the evaporite
Tacotron: Towards End-to-End Speech Synthesis
A text-to-speech synthesis system typically consists of multiple stages, such
as a text analysis frontend, an acoustic model and an audio synthesis module.
Building these components often requires extensive domain expertise and may
contain brittle design choices. In this paper, we present Tacotron, an
end-to-end generative text-to-speech model that synthesizes speech directly
from characters. Given pairs, the model can be trained completely
from scratch with random initialization. We present several key techniques to
make the sequence-to-sequence framework perform well for this challenging task.
Tacotron achieves a 3.82 subjective 5-scale mean opinion score on US English,
outperforming a production parametric system in terms of naturalness. In
addition, since Tacotron generates speech at the frame level, it's
substantially faster than sample-level autoregressive methods.Comment: Submitted to Interspeech 2017. v2 changed paper title to be
consistent with our conference submission (no content change other than typo
fixes
Pigment identification of an illuminated mediaeval manuscript De Civitate Dei by means of a portable Raman equipment
Entropy paradox in strongly correlated Fermi systems
A system of interacting, identical fermions described by standard Landau
Fermi-liquid (FL) theory can experience a rearrangement of its Fermi surface if
the correlations grow sufficiently strong, as occurs at a quantum critical
point where the effective mass diverges. As yet, this phenomenon defies full
understanding, but salient aspects of the non-Fermi-liquid (NFL) behavior
observed beyond the quantum critical point are still accessible within the
general framework of the Landau quasiparticle picture. Self-consistent
solutions of the coupled Landau equations for the quasiparticle momentum
distribution and quasiparticle energy spectrum are shown
to exist in two distinct classes, depending on coupling strength and on whether
the quasiparticle interaction is regular or singular at zero momentum transfer.
One class of solutions maintains the idempotency condition of
standard FL theory at zero temperature while adding pockets to the Fermi
surface. The other solutions are characterized by a swelling of the Fermi
surface and a flattening of the spectrum over a range of momenta
in which the quasiparticle occupancies lie between 0 and 1 even at T=0. The
latter, non-idempotent solution is revealed by analysis of a Poincar\'e mapping
associated with the fundamental Landau equation connecting and
and validated by solution of a variational condition that yields
the symmetry-preserving ground state. Paradoxically, this extraordinary
solution carries the burden of a large temperature-dependent excess entropy
down to very low temperatures, threatening violation of the Nernst Theorem. It
is argued that certain low-temperature phase transitions offer effective
mechanisms for shedding the entropy excess. Available measurements in
heavy-fermion compounds provide concrete support for such a scenario.Comment: 34 pages, 6 figure
Short-range correlations in (e,ep) and (e,epp) reactions on complex nuclei
The influence of short-range correlations (SRC) on the triple-coincidence
(e,epp) reactions is studied. The non-relativistic model uses a mean-field
potential to account for the distortions that the escaping particles undergo.
Apart from the SRC, that are implemented through a Jastrow ansatz with a
realistic correlation function, we incorporate the contribution from pion
exchange and intermediate currents. The (e,epp) cross
sections are predicted to exhibit a sizeable sensitivity to the SRC. The
contribution from the two-nucleon breakup channel to the semi-exclusive
C(e,ep) cross section is calculated in the kinematics of a recent
NIKHEF-K experiment. In the semi-exclusive channel, a selective sensitivity in
terms of the missing energy and momentum to the SRC is found.Comment: 9 pages, Revtex, 3 figures included as an uuencoded and compressed
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