171 research outputs found
SemEval-2018 Task 5: Counting Events and Participants in the Long Tail
This paper discusses SemEval-2018 Task 5: a referential quantification task of counting events and participants in local, long-tail news documents with high ambiguity. The complexity of this task challenges systems to establish the meaning, reference and identity across documents. The task consists of three subtasks and spans across three domains. We detail the design of this referential quantification task, describe the participating systems, and present additional analysis to gain deeper insight into their performance
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Soft Robotics for Chemists
Soft robots: A methodology based on embedded pneumatic networks (PneuNets) is described that enables large-amplitude actuations in soft elastomers by pressurizing embedded channels. Examples include a structure that can change its curvature from convex to concave, and devices that act as compliant grippers for handling fragile objects (e.g., a chicken egg).Chemistry and Chemical Biolog
Soft Fiber-Reinforced Pneumatic Actuator Design and Fabrication: Towards Robust, Soft Robotic Systems
© Springer Nature Switzerland AG 2019. Soft robotics is a rapidly evolving, young research area. So far there are no well-established design standards nor fabrication procedures for soft robots. A number of research groups are working on soft robotics solutions independently and we can observe a range of designs realized in different ways. These soft robots are based on various actuation principles, are driven with various actuation media, and offer various actuation properties. Still, most of them require lots of manual effort and high manual fabrication skills from the person manufacturing these kinds of robots. A significant share of the proposed designs suffers from some imperfections that could be improved by simple design changes. In this work, we propose a number of design and fabrication rules for improving the performance and fabrication complexity of soft fiber-reinforced pneumatic actuators. The proposed design approach focuses on a circular geometry for the pressure chambers and applying a dense, fiber-based reinforcement. Such an approach allows for a more linear actuator response and reduced wear of the actuators, when compared to previous approaches. The proposed manufacturing procedure introduces the application of the reinforcement before the fabrication of the actuator body, significantly reducing the required fabrication effort and providing more consistent and more reliable results
Pretreatment with Pancaspase Inhibitor (Z-VAD-FMK) Delays but Does Not Prevent Intraperitoneal Heat-Killed Group B Streptococcus-Induced Preterm Delivery in a Pregnant Mouse Model
Caspases and apoptosis are thought to play a role in infection-associated preterm-delivery. We have shown that in vitro treatment with pancaspase inhibitor Z-VAD-FMK protects trophoblasts from microbial antigen-induced apoptosis. Objective. To examine whether in vivo administration of Z-VAD-FMK would prevent infection-induced preterm-delivery. Methods. We injected 14.5 day-pregnant-mice with heat-killed group B streptococcus (HK-GBS). Apoptosis within placentas and membranes was assessed by TUNEL staining. Calpain expression and caspase-3 activation were assessed by immunohistochemistry. Preterm-delivery was defined as expulsion of a fetus within 48 hours after injection. Results. Intrauterine (i.u.) or intraperitoneal (i.p.) HK-GBS injection led to preterm-delivery and induced apoptosis in placentas and membranes at 14 hours. The expression of calpain, a caspase-independent inducer of apoptosis, was increased in placenta. Treatment with the specific caspase inhibitor Z-VAD-FMK (i.p.) prior to HK-GBS (i.p.) delayed but did not prevent preterm-delivery. Conclusion. Caspase-dependent apoptosis appears to play a role in the timing but not the occurrence of GBS-induced preterm delivery in the mouse
Thermodyamic bounds on Drude weights in terms of almost-conserved quantities
We consider one-dimensional translationally invariant quantum spin (or
fermionic) lattices and prove a Mazur-type inequality bounding the
time-averaged thermodynamic limit of a finite-temperature expectation of a
spatio-temporal autocorrelation function of a local observable in terms of
quasi-local conservation laws with open boundary conditions. Namely, the
commutator between the Hamiltonian and the conservation law of a finite chain
may result in boundary terms only. No reference to techniques used in Suzuki's
proof of Mazur bound is made (which strictly applies only to finite-size
systems with exact conservation laws), but Lieb-Robinson bounds and exponential
clustering theorems of quasi-local C^* quantum spin algebras are invoked
instead. Our result has an important application in the transport theory of
quantum spin chains, in particular it provides rigorous non-trivial examples of
positive finite-temperature spin Drude weight in the anisotropic Heisenberg XXZ
spin 1/2 chain [Phys. Rev. Lett. 106, 217206 (2011)].Comment: version as accepted by Communications in Mathematical Physics (22
pages with 2 pdf-figures
Thermal behavior of hard-axis magnetization in noninteracting particles with uniaxial anisotropy
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Experimental evidence is presented to support predictions made by an analytical model describing the temperature-dependent behavior of an assembly of noninteracting magnetic nanoparticles with uniaxial anisotropy under an external field. When the applied field is smaller than the anisotropy field of the particles and is oriented perpendicular to the easy axis, a maximum of the magnetization occurs at finite temperature. The theory shows good agreement with measurements of an array of CoCrPt nanoislands with uniaxial anisotropy. Deviations are discussed taking into account the thermal dependencies of the saturation magnetization and the anisotropy of the magnetic material.9520PIIC-DGIP-USMFondecyt Chile [1070224]Millennium Science Initiative ChileFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)CONICYTNational Science Foundation [DMR 02-13282]Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fondecyt Chile [1070224]National Science Foundation [DMR 02-13282
A Hybrid Combining Hard and Soft Robots
This manuscript describes a hybrid robotic system combining hard and soft sub-systems. This hybrid comprises a wheeled robot (an iRobot Create©; hard) and a four-legged quadruped (soft). It is capable (using a simple, wireless control system) of rapid locomotion over flat terrain (using the wheeled hard robot), and of gripping and retrieval of an object (using the soft robot). The utility of this system is demonstrated by performing a mission requiring the capabilities of both components: retrieving an object (iPod Nano®) from the center of a room. This class of robot— hybrids comprising hard and soft systems functioning synergistically—is capable of performing tasks that neither can do alone. In contrast to specialised hard robotic arms with grippers (capable of performing some of the functions we describe here), which are complex, relatively expensive, and require sophisticated controls, this hybrid system is easy to construct, simple to control, and low in cost. The soft robotic system in the hybrid is lightweight, disposable if contaminated or damaged, and capable of multiple functions.Chemistry and Chemical Biolog
From the quantum transfer matrix to the quench action: the Loschmidt echo in XXZ Heisenberg spin chains
We consider the computation of the Loschmidt echo after quantum quenches in the interacting XXZ Heisenberg spin chain both for real and imaginary times. We study two-site product initial states, focusing in particular on the N\ue9el and tilted N\ue9el states. We apply the Quantum Transfer Matrix (QTM) approach to derive generalized TBA equations, which follow from the fusion hierarchy of the appropriate QTM's. Our formulas are valid for arbitrary imaginary time and for real times at least up to a time t0, after which the integral equations have to be modified. In some regimes, t0 is seen to be either very large or infinite, allowing to explore in detail the post-quench dynamics of the system. As an important part of our work, we show that for the N\ue9el state our imaginary time results can be recovered by means of the quench action approach, unveiling a direct connection with the quantum transfer matrix formalism. In particular, we show that in the zero-time limit, the study of our TBA equations allows for a simple alternative derivation of the recently obtained Bethe ansatz distribution functions for the N\ue9el, tilted N\ue9el and tilted ferromagnet states
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