22 research outputs found
Time domain Einstein-Podolsky-Rosen correlation
We experimentally demonstrate creation and characterization of
Einstein-Podolsky-Rosen (EPR) correlation between optical beams in the time
domain. The correlated beams are created with two independent continuous-wave
optical parametric oscillators and a half beam splitter. We define temporal
modes using a square temporal filter with duration and make time-resolved
measurement on the generated state. We observe the correlations between the
relevant conjugate variables in time domain which correspond to the EPR
correlation. Our scheme is extendable to continuous variable quantum
teleportation of a non-Gaussian state defined in the time domain such as a
Schr\"odinger cat-like state.Comment: 4 pages, 4 figure
MaestROB: A Robotics Framework for Integrated Orchestration of Low-Level Control and High-Level Reasoning
This paper describes a framework called MaestROB. It is designed to make the
robots perform complex tasks with high precision by simple high-level
instructions given by natural language or demonstration. To realize this, it
handles a hierarchical structure by using the knowledge stored in the forms of
ontology and rules for bridging among different levels of instructions.
Accordingly, the framework has multiple layers of processing components;
perception and actuation control at the low level, symbolic planner and Watson
APIs for cognitive capabilities and semantic understanding, and orchestration
of these components by a new open source robot middleware called Project Intu
at its core. We show how this framework can be used in a complex scenario where
multiple actors (human, a communication robot, and an industrial robot)
collaborate to perform a common industrial task. Human teaches an assembly task
to Pepper (a humanoid robot from SoftBank Robotics) using natural language
conversation and demonstration. Our framework helps Pepper perceive the human
demonstration and generate a sequence of actions for UR5 (collaborative robot
arm from Universal Robots), which ultimately performs the assembly (e.g.
insertion) task.Comment: IEEE International Conference on Robotics and Automation (ICRA) 2018.
Video: https://www.youtube.com/watch?v=19JsdZi0TW
Inverse square Levy walk emerging universally in goal-oriented tasks
The Levy walk in which the frequency of occurrence of step lengths follows a
power-law distribution, can be observed in the migratory behavior of organisms
at various levels. Levy walks with power exponents close to 2 are observed, and
the reasons are unclear. This study aims to propose a model that universally
generates inverse square Levy walks (called Cauchy walks) and to identify the
conditions under which Cauchy walks appear. We demonstrate that Cauchy walks
emerge universally in goal-oriented tasks. We use the term "goal-oriented" when
the goal is clear, but this can be achieved in different ways, which cannot be
uniquely determined. We performed a simulation in which an agent observed the
data generated from a probability distribution in a two-dimensional space and
successively estimated the central coordinates of that probability
distribution. The agent has a model of probability distribution as a hypothesis
for data-generating distribution and can modify the model such that each time a
data point is observed, thereby increasing the estimated probability of
occurrence of the observed data. To achieve this, the center coordinates of the
model must be moved closer to those of the observed data. However, in the case
of a two-dimensional space, arbitrariness arises in the direction of correction
of the center; this task is goal oriented. We analyze two cases: a strategy
that allocates the amount of modification randomly in the x- and y-directions,
and a strategy that determines allocation such that movement is minimized. The
results reveal that when a random strategy is used, the Cauchy walk appears.
When the minimum strategy is used, the Brownian walk appears. The presence or
absence of the constraint of minimizing the amount of movement may be a factor
that causes the difference between Brownian and Levy walks
Mirtazapine exerts astrocyte-mediated dopaminergic neuroprotection
Mirtazapine, a noradrenergic and specific serotonergic antidepressant (NaSSA), is known to activate serotonin (5-HT) 1A receptor. Our recent study demonstrated that stimulation of astrocytic 5-HT1A receptors promoted astrocyte proliferation and upregulated antioxidative property in astrocytes to protect dopaminergic neurons against oxidative stress. Here, we evaluated the neuroprotective effects of mirtazapine against dopaminergic neurodegeneration in models of Parkinson's disease (PD). Mirtazapine administration attenuated the loss of dopaminergic neurons in the substantia nigra and increased the expression of the antioxidative molecule metallothionein (MT) in the striatal astrocytes of 6-hydroxydopamine (6-OHDA)-injected parkinsonian mice via 5-HT1A receptors. Mirtazapine protected dopaminergic neurons against 6-OHDA-induced neurotoxicity in mesencephalic neuron and striatal astrocyte cocultures, but not in enriched neuronal cultures. Mirtazapine-treated neuron-conditioned medium (Mir-NCM) induced astrocyte proliferation and upregulated MT expression via 5-HT1A receptors on astrocytes. Furthermore, treatment with medium from Mir-NCM-treated astrocytes protected dopaminergic neurons against 6-OHDA neurotoxicity, and these effects were attenuated by treatment with a MT-1/2-specific antibody or 5-HT1A antagonist. Our study suggests that mirtazapine could be an effective disease-modifying drug for PD and highlights that astrocytic 5-HT1A receptors may be a novel target for the treatment of PD
Facile synthesis of indolizino[3,4,5-ab]isoindoles by an acid-induced cyclization of 1,2-di(1H-pyrrol-2-yl)benzenes
The new synthetic method of indolizino[3,4,5-ab]isoindoles (INIs) by an acid-induced intramolecular cyclization of 1,2-di(1H-pyrrol-2-yl)benzenes has been developed. This protocol can be applied to the preparation of INI derivatives with electron-donating and -withdrawing groups as well as azaINIs