5,389 research outputs found
Effects of a Token Economy on a Student with Autism Exhibiting Disruptive Behavior in a General Education Classroom
The Centers for Disease Control and Prevention defines autism spectrum disorder (ASD) as a developmental disability that can cause significant social, communication, and behavioral challenges; and estimates that one in 68 children in the United States are affected by it (CDC, 2014). This prevalence rate is much higher than that of prior decades and has led to trends and factors related to educational programs that include an increase in the inclusion of students with ASD in general education classrooms. For this reason, it is crucial that teachers have access to efficient, teacher-friendly, and research-based interventions for students with ASD in the general education environment. One strategy that has been implemented in many different settings to influence behavior is a token economy system. The purpose of the current study was to examine the effectiveness of a token economy in decreasing disruptive behavior displayed by a student with ASD in a fourth-grade general education classroom. Using an ABAB single subject design, results showed that the studentâs disruptive behavior was at an increased level during the initial baseline condition; decreased as the intervention was introduced; returned to an increased level during the second baseline condition; and decreased again once the intervention was reinstated. Furthermore, the studentâs behavior continued to stay at decreased levels during a maintenance phase
Systematic Visual Reasoning through Object-Centric Relational Abstraction
Human visual reasoning is characterized by an ability to identify abstract
patterns from only a small number of examples, and to systematically generalize
those patterns to novel inputs. This capacity depends in large part on our
ability to represent complex visual inputs in terms of both objects and
relations. Recent work in computer vision has introduced models with the
capacity to extract object-centric representations, leading to the ability to
process multi-object visual inputs, but falling short of the systematic
generalization displayed by human reasoning. Other recent models have employed
inductive biases for relational abstraction to achieve systematic
generalization of learned abstract rules, but have generally assumed the
presence of object-focused inputs. Here, we combine these two approaches,
introducing Object-Centric Relational Abstraction (OCRA), a model that extracts
explicit representations of both objects and abstract relations, and achieves
strong systematic generalization in tasks (including a novel dataset,
CLEVR-ART, with greater visual complexity) involving complex visual displays
Zero-shot visual reasoning through probabilistic analogical mapping
Human reasoning is grounded in an ability to identify highly abstract
commonalities governing superficially dissimilar visual inputs. Recent efforts
to develop algorithms with this capacity have largely focused on approaches
that require extensive direct training on visual reasoning tasks, and yield
limited generalization to problems with novel content. In contrast, a long
tradition of research in cognitive science has focused on elucidating the
computational principles underlying human analogical reasoning; however, this
work has generally relied on manually constructed representations. Here we
present visiPAM (visual Probabilistic Analogical Mapping), a model of visual
reasoning that synthesizes these two approaches. VisiPAM employs learned
representations derived directly from naturalistic visual inputs, coupled with
a similarity-based mapping operation derived from cognitive theories of human
reasoning. We show that without any direct training, visiPAM outperforms a
state-of-the-art deep learning model on an analogical mapping task. In
addition, visiPAM closely matches the pattern of human performance on a novel
task involving mapping of 3D objects across disparate categories
Liver transplantation for late-onset acute liver failure in Wilsonâs disease: the UK experience over two decades
BACKGROUNDS AND AIMS: Acute liver failure as the initial presentation of Wilsonâs disease is usually associated with onset in childhood, adolescence or early adulthood. Outcomes after transplantation for late-onset presentations, at or after 40 years, are seldom reported in the literature METHODS: We report a case, review the literature and provide unpublished data from the UK Transplant Registry on late-onset acute liver failure in Wilsonâs disease. RESULTS: We describe a 62-year-old man presenting with acute liver failure who was successfully treated with urgent liver transplantation. We identified seven cases presenting at age 40 years or over in the literature where individual outcomes were reported; three were treated with transplantation and two survived. We identified a further eight cases listed for transplantation in the UK between 1995 and 2014; seven were treated with transplantation and six survived. One patient was de-listed for unknown reasons. CONCLUSIONS: We discuss the need to consider Wilsonâs disease in older adults presenting with acute liver failure and importance of making the diagnosis prior to transplantation. We suggest that urgent liver transplantation has good outcomes for late-onset presentations and recommend that urgent transplantation should always be considered in Wilsonâs disease presenting with acute liver failure
Learning Representations that Support Extrapolation
Extrapolation -- the ability to make inferences that go beyond the scope of
one's experiences -- is a hallmark of human intelligence. By contrast, the
generalization exhibited by contemporary neural network algorithms is largely
limited to interpolation between data points in their training corpora. In this
paper, we consider the challenge of learning representations that support
extrapolation. We introduce a novel visual analogy benchmark that allows the
graded evaluation of extrapolation as a function of distance from the convex
domain defined by the training data. We also introduce a simple technique,
temporal context normalization, that encourages representations that emphasize
the relations between objects. We find that this technique enables a
significant improvement in the ability to extrapolate, considerably
outperforming a number of competitive techniques.Comment: ICML 202
The Relational Bottleneck as an Inductive Bias for Efficient Abstraction
A central challenge for cognitive science is to explain how abstract concepts
are acquired from limited experience. This effort has often been framed in
terms of a dichotomy between empiricist and nativist approaches, most recently
embodied by debates concerning deep neural networks and symbolic cognitive
models. Here, we highlight a recently emerging line of work that suggests a
novel reconciliation of these approaches, by exploiting an inductive bias that
we term the relational bottleneck. We review a family of models that employ
this approach to induce abstractions in a data-efficient manner, emphasizing
their potential as candidate models for the acquisition of abstract concepts in
the human mind and brain
Biomineralisation in the Palaeozoic oceans: evidence for simultaneous crystallisation of high and low magnesium calcite by phacopine trilobites
The chemical composition and microstructure of the calcite cuticles of eleven species of phacopine trilobites have been investigated by electron beam imaging, diffraction, and microanalysis, and results reveal that the lenses of their schizochroal eyes differed signiïŹcantly in chemical composition from the rest of the cuticle in vivo. Apart from the eye lenses, most cuticles are inferred to have escaped extensive recrystallisation because their constituent crystals are sub-micrometre in size and have a preferred orientation that is consistent between species. Their current compositions of ~1.4 to 2.4 mol% MgCO3 are likely to be close to original values, although as they commonly luminesce and contain detectable manganese and iron, some diagenetic alteration has taken place. The associated lenses have a microstructure that is suitable for focusing light, yet are optically turbid owing to the presence within calcite of micropores and crystals of microdolomite, apatite, celestite and pyrite. The microdolomite indicates that lenses recrystallised from an original high-Mg calcite composition and this is supported by the presence of nanometre-scale modulated microstructures in both the calcite and dolomite. These lenses currently contain ~1 to 6 mol% MgCO3, and by comparison with the proportion of magnesium lost from echinoderm stereom in the same thin sections, may have contained ~7.5 mol% MgCO3 in vivo. In some samples, more extensive diagenetic alteration is evidenced by recrystallisation of the cuticle including lenses to coarse equant calcite or enrichment of the cuticle, but not necessarily the lenses, in magnesium accompanying replacement by a MgâFe phyllosilicate. The phacopine trilobites had to modify partition coefïŹcients for magnesium considerably in order to grow lenses with contrasting compositions to the rest of their cuticles, and such a strong vital effect on biomineralisation suggests that incorporation of magnesium was essential for functioning of their calcite optical s
The Space Density and Colors of Massive Galaxies at 2<z<3: the Predominance of Distant Red Galaxies
Using the deep multi-wavelength MUSYC, GOODS, and FIRES surveys we construct
a stellar mass-limited sample of galaxies at 2<z<3. The sample comprises 294
galaxies with M>10^11 Solar masses distributed over four independent fields
with a total area of almost 400 sq arcmin. The mean number density of massive
galaxies in this redshift range is (2.2+-0.6) x 10^-4 Mpc^-3. We present median
values and 25th and 75th percentiles for the distributions of observed R mags,
observed J-K colors, and rest-frame UV continuum slopes, M/L(V) ratios, and U-V
colors. The galaxies show a large range in all these properties. The ``median
galaxy'' is faint in the observer's optical (R=25.9), red in the observed
near-IR (J-K=2.48), has a rest-frame UV spectrum which is relatively flat
(beta=-0.4), and rest-frame optical colors resembling those of nearby spiral
galaxies (U-V=0.62). We determine which galaxies would be selected as Lyman
break galaxies (LBGs) or Distant Red Galaxies (DRGs, having J-K>2.3) in this
mass-limited sample. By number DRGs make up 69% of the sample and LBGs 20%,
with a small amount of overlap. By mass DRGs make up 77% and LBGs 17%. Neither
technique provides a representative sample of massive galaxies at 2<z<3 as they
only sample the extremes of the population. As we show here, multi-wavelength
surveys with high quality photometry are essential for an unbiased census of
massive galaxies in the early Universe. The main uncertainty in this analysis
is our reliance on photometric redshifts; confirmation of the results presented
here requires extensive near-infrared spectroscopy of optically-faint samples.Comment: Accepted for publication in ApJ Letter
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