177,930 research outputs found
Robo-AO M-dwarf Multiplicity Survey: Catalog
We analyze observations from Robo-AO's field M dwarf survey taken on the 2.1 m Kitt Peak telescope and perform a multiplicity comparison with Gaia DR2. Through its laser-guided, automated system, the Robo-AO instrument has yielded the largest adaptive optics M dwarf multiplicity survey to date. After developing an interface to visually identify and locate stellar companions, we selected 11 low-significance Robo-AO detections for follow-up on the Keck II telescope using NIRC2. In the Robo-AO survey we find 553 candidate companions within 4'' around 534 stars out of 5566 unique targets, most of which are new discoveries. Using a position cross-match with DR2 on all targets, we assess the binary recoverability of Gaia DR2 and compare the properties of multiples resolved by both Robo-AO and Gaia. The catalog of nearby M dwarf systems and their basic properties presented here can assist other surveys which observe these stars, such as the NASA TESS mission
The Robo-AO-2 facility for rapid visible/near-infrared AO imaging and the demonstration of hybrid techniques
We are building a next-generation laser adaptive optics system, Robo-AO-2,
for the UH 2.2-m telescope that will deliver robotic, diffraction-limited
observations at visible and near-infrared wavelengths in unprecedented numbers.
The superior Maunakea observing site, expanded spectral range and rapid
response to high-priority events represent a significant advance over the
prototype. Robo-AO-2 will include a new reconfigurable natural guide star
sensor for exquisite wavefront correction on bright targets and the
demonstration of potentially transformative hybrid AO techniques that promise
to extend the faintness limit on current and future exoplanet adaptive optics
systems.Comment: 15 page
N-cadherin acts in concert with Slit1-Robo2 signaling in regulating aggregation of placode-derived cranial sensory neurons
Vertebrate cranial sensory ganglia have a dual origin from the neural crest and ectodermal placodes. In the largest of these, the trigeminal ganglion, Slit1-Robo2 signaling is essential for proper ganglion assembly. Here, we demonstrate a crucial role for the cell adhesion molecule N-cadherin and its interaction with Slit1-Robo2 during gangliogenesis in vivo. A common feature of chick trigeminal and epibranchial ganglia is the expression of N-cadherin and Robo2 on placodal neurons and Slit1 on neural crest cells. Interestingly, N-cadherin localizes to intercellular adherens junctions between placodal neurons during ganglion assembly. Depletion of N-cadherin causes loss of proper ganglion coalescence, similar to that observed after loss of Robo2, suggesting that the two pathways might intersect. Consistent with this possibility, blocking or augmenting Slit-Robo signaling modulates N-cadherin protein expression on the placodal cell surface concomitant with alteration in placodal adhesion. Lack of an apparent change in total N-cadherin mRNA or protein levels suggests post-translational regulation. Co-expression of N-cadherin with dominant-negative Robo abrogates the Robo2 loss-of-function phenotype of dispersed ganglia, whereas loss of N-cadherin reverses the aberrant aggregation induced by increased Slit-Robo expression. Our study suggests a novel mechanism whereby N-cadherin acts in concert with Slit-Robo signaling in mediating the placodal cell adhesion required for proper gangliogenesis
Social inclusion and inclusive education
The key question addressed in this article is social inclusion, as an opposite concept of social exclusion. The author provides a historical of social inclusion/exclusion terminology. Further, some of the principles of social inclusion are presented. A brief review of the literature provides key views and theories of social inclusion. In particular, the author brings to attention that the included/excluded dualism apparent in the writings of social inclusion and exclusion cannot be taken at face value. In line with global debate on social inclusion and exclusion, the author brings the way this debate has now pervaded both the official and development policy discourse in Albania.Social inclusion is considered as one of the priorities of the current government, with poverty reduction as its main focus, which will be ensured not only through economic development. In the end, the article focuses on the role of education as a very important and useful tool for ensuring social inclusion.Social inclusion through education, in particular through vocational education, considered by the author as the only way towards sustainable development of Albanian society
Laser-only adaptive optics achieves significant image quality gains compared to seeing-limited observations over the entire sky
Adaptive optics laser guide star systems perform atmospheric correction of
stellar wavefronts in two parts: stellar tip-tilt and high-spatial-order
laser-correction. The requirement of a sufficiently bright guide star in the
field-of-view to correct tip-tilt limits sky coverage. Here we show an
improvement to effective seeing without the need for nearby bright stars,
enabling full sky coverage by performing only laser-assisted wavefront
correction. We used Robo-AO, the first robotic AO system, to comprehensively
demonstrate this laser-only correction. We analyze observations from four years
of efficient robotic operation covering 15,000 targets and 42,000 observations,
each realizing different seeing conditions. Using an autoguider (or a
post-processing software equivalent) and the laser to improve effective seeing
independent of the brightness of a target, Robo-AO observations show a 39+/-19%
improvement to effective FWHM, without any tip-tilt correction. We also
demonstrate that 50% encircled-energy performance without tip-tilt correction
remains comparable to diffraction-limited, standard Robo-AO performance.
Faint-target science programs primarily limited by 50% encircled-energy (e.g.
those employing integral field spectrographs placed behind the AO system) may
see significant benefits to sky coverage from employing laser-only AO.Comment: Accepted for publication in The Astronomical Journal. 7 pages, 6
figure
Requirement for Slit-1 and Robo-2 in zonal segregation of olfactory sensory neuron axons in the main olfactory bulb
The formation of precise stereotypic connections in sensory systems is critical for the ability to detect and process signals from the environment. In the olfactory system, olfactory sensory neurons (OSNs) project axons to spatially defined glomeruli within the olfactory bulb (OB). A spatial relationship exists between the location of OSNs within the olfactory epithelium (OE) and their glomerular targets
along the dorsoventral axis in the OB. The molecular mechanisms underlying the zonal segregation of OSN axons along the dorsoventral axis of the OB are poorly understood. Using robo-2/ (roundabout) and slit-1/ mice, we examined the role of the Slit family of axon
guidance cues in the targeting of OSN axons during development. We show that a subset of OSN axons that normally project to the dorsal region of the OB mistarget and form glomeruli in the ventral region in robo-2/ and slit-1/ mice. In addition, we show that the Slit
receptor, Robo-2, is expressed in OSNs in a high dorsomedial to low ventrolateral gradient across the OE and that Slit-1 and Slit-3 are expressed in the ventral region of the OB. These results indicate that the dorsal-to-ventral segregation of OSN axons are not solely defined
by the location of OSNs within the OE but also relies on axon guidance cues
Algorithms & Fiduciaries: Existing and Proposed Regulatory Approaches to Artificially Intelligent Financial Planners
Artificial intelligence is no longer solely in the realm of science fiction. Today, basic forms of machine learning algorithms are commonly used by a variety of companies. Also, advanced forms of machine learning are increasingly making their way into the consumer sphere and promise to optimize existing markets. For financial advising, machine learning algorithms promise to make advice available 24–7 and significantly reduce costs, thereby opening the market for financial advice to lower-income individuals. However, the use of machine learning algorithms also raises concerns. Among them, whether these machine learning algorithms can meet the existing fiduciary standard imposed on human financial advisers and how responsibility and liability should be partitioned when an autonomous algorithm falls short of the fiduciary standard and harms a client. After summarizing the applicable law regulating investment advisers and the current state of robo-advising, this Note evaluates whether robo-advisers can meet the fiduciary standard and proposes alternate liability schemes for dealing with increasingly sophisticated machine learning algorithms
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