2,028 research outputs found
Intersegmental Coordination in the Kinematics of Prehension Movements of Macaques
The most popular model to explain how prehensile movements are organized assumes that they comprise two "components", the reaching component encoding information regarding the object's spatial location and the grasping component encoding information on the object's intrinsic properties such as size and shape. Comparative kinematic studies on grasping behavior in the humans and in macaques have been carried out to investigate the similarities and differences existing across the two species. Although these studies seem to favor the hypothesis that macaques and humans share a number of kinematic features it remains unclear how the reaching and grasping components are coordinated during prehension movements in free-ranging macaque monkeys. Twelve hours of video footage was filmed of the monkeys as they snatched food items from one another (i.e., snatching) or collect them in the absence of competitors (i.e., unconstrained). The video samples were analyzed frame-by-frame using digitization techniques developed to perform two-dimensional post-hoc kinematic analyses of the two types of actions. The results indicate that only for the snatching condition when the reaching variability increased there was an increase in the amplitude of maximum grip aperture. Besides, the start of a break-point along the deceleration phase of the velocity profile correlated with the time at which maximum grip aperture occurred. These findings suggest that macaques can spatially and temporally couple the reaching and the grasping components when there is pressure to act quickly. They offer a substantial contribution to the debate about the nature of how prehensile actions are programmed
Design and implementation of an automatic measurement system for the characterization of power MOSFETs
Peer Reviewe
Stoquasticity in circuit QED
We analyze whether circuit-QED Hamiltonians are stoquastic focusing on
systems of coupled flux qubits: we show that scalable sign-problem free path
integral Monte Carlo simulations can typically be performed for such systems.
Despite this, we corroborate the recent finding [arXiv:1903.06139] that an
effective, non-stoquastic qubit Hamiltonian can emerge in a system of
capacitively coupled flux qubits. We find that if the capacitive coupling is
sufficiently small, this non-stoquasticity of the effective qubit Hamiltonian
can be avoided if we perform a canonical transformation prior to projecting
onto an effective qubit Hamiltonian. Our results shed light on the power of
circuit-QED Hamiltonians for the use of quantum adiabatic computation and the
subtlety of finding a representation which cures the sign problem in these
system
Existence of Positive Eigenfunctions to an Anisotropic Elliptic Operator via Sub-Super Solutions Method
Using the sub-supersolution method we study the existence of positive
solutions for the anisotropic problem \begin{equation}
-\sum_{i=1}^N\frac{\partial}{\partial x_i}\left( \left|\frac{\partial
u}{\partial x_i}\right|^{p_i-2}\frac{\partial u}{\partial x_i}\right)=\lambda
u^{q-1} \end{equation} where is a bounded and regular domain of
, and .Comment: 11 pages, references 16 title
Use of surrogate endpoints in healthcare policy : proposal for consistent adoption of a validation framework
We propose a three step framework for the evaluation of surrogate endpoints for health policy decisions on health technologies
Surrogate endpoints in trials-a call for better reporting
Better reporting of RCTs with primary surrogate endpoints
Ecological Distribution and Oenological Characterization of Native Saccharomyces cerevisiae in an Organic Winery
The relation between regional yeast biota and the organoleptic characteristics of wines has attracted growing attention among winemakers. In this work, the dynamics of a native Saccharomyces cerevisiae
population was investigated in an organic winery. In this regard, the occurrence and the persistence of
native S. cerevisiae were evaluated in the vineyard and winery and during spontaneous fermentation of
two nonconsecutive vintages. From a total of 98 strains, nine different S. cerevisiae biotypes were identified
that were distributed through the whole winemaking process, and five of them persisted in both vintages.
The results of the oenological characterization of the dominant biotypes (I and II) show a fermentation
behavior comparable to that exhibited by three common commercial starter strains, exhibiting specific
aromatic profiles. Biotype I was characterized by some fruity aroma compounds, such as isoamyl acetate
and ethyl octanoate, while biotype II was differentiated by ethyl hexanoate, nerol, and β-damascenone
production also in relation to the fermentation temperature. These results indicate that the specificity of
these resident strains should be used as starter cultures to obtain wines with distinctive aromatic profiles
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