1,067 research outputs found
Distribution of soft drinks in the greater Boston area.
Thesis (M.B.A.)--Boston Universit
School Leadership and Equity : an examination of policy response in Scotland
In this paper we adopt a critical perspective on the implementation of policy on school leadership and equity in Scotland, viewing policy as both an attempt to solve problems and an attempt to persuade social actors to subscribe to particular beliefs that delineate action. We begin by offering a definition of “policy response”, and then examine how policy “conversations” establish consensus around such things as school leadership and equity. We examine Scottish policy on school leadership and equity and consider what practices this policy does, and does not permit. In so doing, our examination of the implementation of policy on school leadership and equity in Scotland acknowledges that such policy is in part extemporized, and in part the attempt to make inevitable a “de-stated” account of governance. We conclude by contextualising our forthcoming empirical study of the Leadership Standards for Social Justice in Scotlan
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
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Network operations support plan for Apollo Lunar Surface Experiments Package
The purpose of this Network Operations Support Plan (NOSP) is to provide operational configurations and procedures applicable to the Apollo Lunar Surface Experiments Packages (ALSEP). Some information on the Particles and Fields Subsatellite (P&FS) has been retained for historical purposes. The provisions of this document take precedence over procedures contained in other documents.Carl O. Roberts, Michael T. Ward.Mission operations -- Telemetry -- Unified S-band -- Station computer systems -- command -- Computer support -- Data management -- Station communications system -- NOCC/station interface -- Network testing and simulations -- 12-meter (40-foot) tracking antenna system -- 26-meter (85-foot) tracking antenna system -- ALSEP sunrise/sunset predictionsRevision
A Day on the Nile: Living in a Town in Nubia
As archaeologists, we are often asked what it was like to live in the past. By blending a fictional narrative with factual archaeological evidence, we offer an interpretation of what a typical day may have been like living at Sai, a town on an island in the River Nile during the second millennium before the common era (BCE), in what is now Sudan. We focus on the question at different levels, thinking about the day-to-day life of the residents of an ancient town, activities that took place, and its broader historical, geographical, and cultural contexts. We also explain how archaeologists work and interpret some of the evidence we discuss, focusing on a range of methods. These include recent advances in virtual 3-D reconstruction, which offer a unique perspective on our interpretation of the past. Many themes covered in this article are highly relevant today and can be linked to several UN Sustainable Development Goals (in particular, 9, 11, and 12). We encourage readers to think about some of the things we discuss in relation to their own lives and experiences and have provided a number of call-out questions in speech bubbles throughout the article to get some of these discussions started
The Predictability of Commodity Trading Advisor Returns
This study investigates the performance and predictability of returns generated by advisors to Commodity Trading Funds from 1979 through 1989. Rates of return and Sharpe Ratios show evidence of predictability from one year to the next for all Commodity Trading Advisors (CTAs). Returns for the top one-third and top 5 performing CTAs show more predictability than for all CTAs
Matrix Pencils and Entanglement Classification
In this paper, we study pure state entanglement in systems of dimension
. Two states are considered equivalent if they can be
reversibly converted from one to the other with a nonzero probability using
only local quantum resources and classical communication (SLOCC). We introduce
a connection between entanglement manipulations in these systems and the
well-studied theory of matrix pencils. All previous attempts to study general
SLOCC equivalence in such systems have relied on somewhat contrived techniques
which fail to reveal the elegant structure of the problem that can be seen from
the matrix pencil approach. Based on this method, we report the first
polynomial-time algorithm for deciding when two states
are SLOCC equivalent. Besides recovering the previously known 26 distinct SLOCC
equivalence classes in systems, we also determine the
hierarchy between these classes
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Covalent targeting of the vacuolar H+-ATPase activates autophagy via mTORC1 inhibition.
Autophagy is a lysosomal degradation pathway that eliminates aggregated proteins and damaged organelles to maintain cellular homeostasis. A major route for activating autophagy involves inhibition of the mTORC1 kinase, but current mTORC1-targeting compounds do not allow complete and selective mTORC1 blockade. Here, we have coupled screening of a covalent ligand library with activity-based protein profiling to discover EN6, a small-molecule in vivo activator of autophagy that covalently targets cysteine 277 in the ATP6V1A subunit of the lysosomal v-ATPase, which activates mTORC1 via the Rag guanosine triphosphatases. EN6-mediated ATP6V1A modification decouples the v-ATPase from the Rags, leading to inhibition of mTORC1 signaling, increased lysosomal acidification and activation of autophagy. Consistently, EN6 clears TDP-43 aggregates, a causative agent in frontotemporal dementia, in a lysosome-dependent manner. Our results provide insight into how the v-ATPase regulates mTORC1, and reveal a unique approach for enhancing cellular clearance based on covalent inhibition of lysosomal mTORC1 signaling
Robo-AO Kepler Survey IV: the effect of nearby stars on 3857 planetary candidate systems
We present the overall statistical results from the Robo-AO Kepler planetary
candidate survey, comprising of 3857 high-angular resolution observations of
planetary candidate systems with Robo-AO, an automated laser adaptive optics
system. These observations reveal previously unknown nearby stars blended with
the planetary candidate host star which alter the derived planetary radii or
may be the source of an astrophysical false positive transit signal. In the
first three papers in the survey, we detected 440 nearby stars around 3313
planetary candidate host stars. In this paper, we present observations of 532
planetary candidate host stars, detecting 94 companions around 88 stars; 84 of
these companions have not previously been observed in high-resolution. We also
report 50 more-widely-separated companions near 715 targets previously observed
by Robo-AO. We derive corrected planetary radius estimates for the 814
planetary candidates in systems with a detected nearby star. If planetary
candidates are equally likely to orbit the primary or secondary star, the
radius estimates for planetary candidates in systems with likely bound nearby
stars increase by a factor of 1.54, on average. We find that 35
previously-believed rocky planet candidates are likely not rocky due to the
presence of nearby stars. From the combined data sets from the complete Robo-AO
KOI survey, we find that 14.5\pm0.5% of planetary candidate hosts have a nearby
star with 4", while 1.2% have two nearby stars and 0.08% have three. We find
that 16% of Earth-sized, 13% of Neptune-sized, 14% of Saturn-sized, and 19% of
Jupiter-sized planet candidates have detected nearby stars.Comment: Accepted to the Astronomical Journa
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