2,532 research outputs found
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Between Protest, Compromise, and Education for Radical Change: Black Power Schools in Harlem in the Late 1960s
In response to stalled struggles for equal and integrated education by African American students, parents, teachers, and activists, Harlem in the late 1960s saw a number of independent schools emerge that drew inspiration and rhetoric from Black Power ideas. This dissertation investigated the reasons for these schools’ emergence in Harlem; what goals these institutions pursued; how they translated their goals, purposes, and ideas into pedagogical practices and curricula; and how these were adapted to the specific challenges faced by the schools by closely examining three such initiatives: West Harlem Liberation School; the storefront academies run by the New York Urban League; and West Side Street Academy, later renamed Academy for Black and Latin Education (ABLE). All of these schools incorporated values and ideas that were central to the philosophy of Black Power, such as an emphasis on self-determination, self-sufficiency, self-reliance, Black history, and cultural pride. However, the ways in which these core ideas of Black Power were interpreted and put into practice varied significantly between different initiatives, especially as they had to navigate daily necessities such as applying for funding or making compromises with corporate donors, foundations, or the New York City Board of Education. Thus, while some of these educational institutions explicitly pursued activist agendas—by positioning themselves as a means to pressure the public school system into fundamental change or by conceptualizing education explicitly as a tool for collectively dismantling systems of oppression—others came to favor approaches designed to uplift individual students rather than pursue more radical social change.
While scholars have extensively studied the fights for desegregation and community control of public schools in Harlem and New York City, the establishment of these Black alternative educational initiatives outside of the public school system as an extension of the movement for quality and equitable education—and as a part of social justice movements, including the Black Power Movement, more broadly—has rarely been considered. These schools and their approaches also provide a unique lens through which to study and re-evaluate Black Power ideas: They reflect the diversity and contradictions of the movement, the different goals and avenues for change that activists within that movement envisioned, and how the theories and ideas of Black Power were translated into practice on the local level in specific issues
Affine Extractors and AC0-Parity
We study a simple and general template for constructing affine extractors by composing a linear transformation with resilient functions. Using this we show that good affine extractors can be computed by non-explicit circuits of various types, including AC0-Xor circuits: AC0 circuits with a layer of parity gates at the input. We also show that one-sided extractors can be computed by small DNF-Xor circuits, and separate these circuits from other well-studied classes. As a further motivation for studying DNF-Xor circuits we show that if they can approximate inner product then small AC0-Xor circuits can compute it exactly - a long-standing open problem
Face Detection with Effective Feature Extraction
There is an abundant literature on face detection due to its important role
in many vision applications. Since Viola and Jones proposed the first real-time
AdaBoost based face detector, Haar-like features have been adopted as the
method of choice for frontal face detection. In this work, we show that simple
features other than Haar-like features can also be applied for training an
effective face detector. Since, single feature is not discriminative enough to
separate faces from difficult non-faces, we further improve the generalization
performance of our simple features by introducing feature co-occurrences. We
demonstrate that our proposed features yield a performance improvement compared
to Haar-like features. In addition, our findings indicate that features play a
crucial role in the ability of the system to generalize.Comment: 7 pages. Conference version published in Asian Conf. Comp. Vision
201
Measuring the Temperature of Hot Nuclear Fragments
A new thermometer based on fragment momentum fluctuations is presented. This
thermometer exhibited residual contamination from the collective motion of the
fragments along the beam axis. For this reason, the transverse direction has
been explored. Additionally, a mass dependence was observed for this
thermometer. This mass dependence may be the result of the Fermi momentum of
nucleons or the different properties of the fragments (binding energy, spin
etc..) which might be more sensitive to different densities and temperatures of
the exploding fragments. We expect some of these aspects to be smaller for
protons (and/or neutrons); consequently, the proton transverse momentum
fluctuations were used to investigate the temperature dependence of the source
Ensemble of Hankel Matrices for Face Emotion Recognition
In this paper, a face emotion is considered as the result of the composition
of multiple concurrent signals, each corresponding to the movements of a
specific facial muscle. These concurrent signals are represented by means of a
set of multi-scale appearance features that might be correlated with one or
more concurrent signals. The extraction of these appearance features from a
sequence of face images yields to a set of time series. This paper proposes to
use the dynamics regulating each appearance feature time series to recognize
among different face emotions. To this purpose, an ensemble of Hankel matrices
corresponding to the extracted time series is used for emotion classification
within a framework that combines nearest neighbor and a majority vote schema.
Experimental results on a public available dataset shows that the adopted
representation is promising and yields state-of-the-art accuracy in emotion
classification.Comment: Paper to appear in Proc. of ICIAP 2015. arXiv admin note: text
overlap with arXiv:1506.0500
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Big bottlenecks in cardiovascular tissue engineering.
Although tissue engineering using human-induced pluripotent stem cells is a promising approach for treatment of cardiovascular diseases, some limiting factors include the survival, electrical integration, maturity, scalability, and immune response of three-dimensional (3D) engineered tissues. Here we discuss these important roadblocks facing the tissue engineering field and suggest potential approaches to overcome these challenges
Magnomechanical backaction corrections due to coupling to higher order Walker modes and Kerr nonlinearities
The radiation pressure-like coupling between magnons and phonons in magnets
can modify the phonon frequency (magnomechanical spring effect) and decay rate
(magnomechanical decay) via dynamical backaction. Such effects have been
recently observed by coupling the uniform magnon mode of a magnetic sphere (the
Kittel mode) to a microwave cavity. In particular, the ability to evade
backaction effects was demonstrated [C.A. Potts et al., arXiv:2211.13766
[quant-ph] (2022)], a requisite for applications such as magnomechanical based
thermometry. However, deviations were observed from the predicted
magnomechanical decay rate within the standard theoretical model. In this work,
we account for these deviations by considering corrections due to (i) magnetic
Kerr nonlinearities and (ii) the coupling of phonons to additional magnon
modes. Provided that such additional modes couple weakly to the driven cavity,
our model yields a correction proportional to the average Kittel magnon mode
occupation. We focus our results on magnetic spheres, where we show that the
magnetostatic Walker modes couple to the relevant mechanical modes as
efficiently as the Kittel mode. Our model yields excellent agreement with the
experimental data.Comment: 20 pages, 9 figure
Dynamical Backaction Evading Magnomechanics
The interaction between magnons and mechanical vibrations dynamically modify
the properties of the mechanical oscillator, such as its frequency and decay
rate. Known as dynamical backaction, this effect is the basis for many
theoretical protocols, such as entanglement generation or mechanical
ground-state cooling. However, dynamical backaction is also detrimental for
specific applications. Here, we demonstrate the implementation of a cavity
magnomechanical measurement that fully evades dynamical backaction effects.
Through careful engineering, the magnomechanical scattering rate into the
hybrid magnon-photon modes can be precisely matched, eliminating dynamical
backaction damping. Backaction evasion is confirmed via the measurement of a
drive-power-independent mechanical linewidth.Comment: 6 pages, 5 figure
Automated segmentation by pixel classification of retinal layers in ophthalmic OCT images
Current OCT devices provide three-dimensional (3D) in-vivo images of the human retina. The resulting very large data sets are difficult to manually assess. Automated segmentation is required to automatically process the data and produce images that are clinically useful and easy to interpret. In this paper, we present a method to segment the retinal layers in these images. Instead of using complex heuristics to define each layer, simple features are defined and machine learning classifiers are trained based on manually labeled examples. When applied to new data, these classifiers produce labels for every pixel. After regularization of the 3D labeled volume to produce a surface, this results in consistent, three-dimensionally segmented layers that match known retinal morphology. Six labels were defined, corresponding to the following layers: Vitreous, retinal nerve fiber layer (RNFL), ganglion cell layer & inner plexiform layer, inner nuclear layer & outer plexiform layer, photoreceptors & retinal pigment epithelium and choroid. For both normal and glaucomatous eyes that were imaged with a Spectralis (Heidelberg Engineering) OCT system, the five resulting interfaces were compared between automatic and manual segmentation. RMS errors for the top and bottom of the retina were between 4 and 6 ÎĽm, while the errors for intra-retinal interfaces were between 6 and 15 ÎĽm. The resulting total retinal thickness maps corresponded with known retinal morphology. RNFL thickness maps were compared to GDx (Carl Zeiss Meditec) thickness maps. Both maps were mostly consistent but local defects were better visualized in OCT-derived thickness maps
General entanglement
The paper contains a brief review of an approach to quantum entanglement
based on analysis of dynamic symmetry of systems and quantum uncertainties,
accompanying the measurement of mean value of certain basic observables. The
latter are defined in terms of the orthogonal basis of Lie algebra,
corresponding to the dynamic symmetry group. We discuss the relativity of
entanglement with respect to the choice of basic observables and a way of
stabilization of robust entanglement in physical systems.Comment: 7 pages, 1 figure,1 tabe, will be published in special issue of
Journal of Physics (Conference Series) with Proceedings of CEWQO-200
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