1,375 research outputs found
An architecture for systematic tracking of skills and competence level progression in computer science
A typical Computer Science degree is three to five years long, consists of four to six subjects per semester, and two semesters per year. A student enrolled in such a degree is expected to learn both discipline-specific skills and transferable generic skills. These skills are to be taught in a progressive sequence through the duration of the degree. As the student progresses through the subjects and semesters of a degree, his skill portfolio and competence level for each skill is expected to grow. Effectively modeling these curriculum skills, mapping them to assessment tasks across subjects of a degree, and measuring the progression in learner competence level is, largely, still an unsolved problem. Previous work at this scale is limited. This systematic tracking of skills and competence is crucial for effective quality control and optimization of degree structures. Our main contribution is an architecture for a curriculum information management system to facilitate this systematic tracking of skill and competence level progression in a Computer Science context
Phylogenetic inferences of Atelinae (Platyrrhini) based on multi-directional chromosome painting in Brachyteles arachnoides, Ateles paniscus paniscus and Ateles b. marginatus
We performed multi-directional chromosome painting in a comparative cytogenetic study of the three Atelinae species Brachyteles arachnoides, Ateles paniscus paniscus and Ateles belzebuth marginatus, in order to reconstruct phylogenetic relationships within this Platyrrhini subfamily. Comparative chromosome maps between these species were established by multi-color fluorescence in situ hybridization ( FISH) employing human, Saguinus oedipus and Lagothrix lagothricha chromosome-specific probes. The three species included in this study and four previously analyzed species from all four Atelinae genera were subjected to a phylogenetic analysis on the basis of a data matrix comprised of 82 discrete chromosome characters. The results confirmed that Atelinae represent a monophyletic clade with a putative ancestral karyotype of 2n = 62 chromosomes. Phylogenetic analysis revealed an evolutionary branching sequence \{Alouatta \{Brachyteles \{Lagothrix and Ateles\}\}\} in Atelinae and \{Ateles belzebuth marginatus \{Ateles paniscus paniscus \{Ateles belzebuth hybridus and Ateles geoffroyi\}\}\} in genus Ateles. The chromosomal data support a re-evaluation of the taxonomic status of Ateles b. hybridus. Copyright (C) 2005 S. Karger AG, Basel
Distant X-ray Galaxies: Insights from the Local Population
A full understanding of the origin of the hard X-ray background requires a
complete and accurate census of the distant galaxies that produce it.
Unfortunately, distant X-ray galaxies tend to be very faint at all wavelengths,
which hinders efforts to perform this census. This chapter discusses the
insights that can be obtained through comparison of the distant population to
local X-ray galaxies, whose properties are well characterized. Such comparisons
will ultimately aid investigations into the cosmic evolution of supermassive
black holes and their environments.Comment: 19 pages, 10 figures, to appear as Chapter 7 in "Supermassive Black
Holes in the Distant Universe" (2004), ed. A. J. Barger, Kluwer Academic
Publishers, in pres
The effectiveness of public health interventions to reduce the health impact of climate change:a systematic review of systematic reviews
Climate change is likely to be one of the most important threats to public health in the coming years. Yet despite the large number of papers considering the health impact of climate change, few have considered what public health interventions may be of most value in reducing the disease burden. We aimed to evaluate the effectiveness of public health interventions to reduce the disease burden of high priority climate sensitive diseases
Amplification of asynchronous inhibition-mediated synchronization by feedback in recurrent networks
Synchronization of 30-80 Hz oscillatory activity of the principle neurons in the olfactory bulb (mitral cells) is believed to be important for odor discrimination. Previous theoretical studies of these fast rhythms in other brain areas have proposed that principle neuron synchrony can be mediated by short-latency, rapidly decaying inhibition. This phasic inhibition provides a narrow time window for the principle neurons to fire, thus promoting synchrony. However, in the olfactory bulb, the inhibitory granule cells produce long lasting, small amplitude, asynchronous and aperiodic inhibitory input and thus the narrow time window that is required to synchronize spiking does not exist. Instead, it has been suggested that correlated output of the granule cells could serve to synchronize uncoupled mitral cells through a mechanism called "stochastic synchronization", wherein the synchronization arises through correlation of inputs to two neural oscillators. Almost all work on synchrony due to correlations presumes that the correlation is imposed and fixed. Building on theory and experiments that we and others have developed, we show that increased synchrony in the mitral cells could produce an increase in granule cell activity for those granule cells that share a synchronous group of mitral cells. Common granule cell input increases the input correlation to the mitral cells and hence their synchrony by providing a positive feedback loop in correlation. Thus we demonstrate the emergence and temporal evolution of input correlation in recurrent networks with feedback. We explore several theoretical models of this idea, ranging from spiking models to an analytically tractable model. © 2010 Marella, Ermentrout
Entanglement distribution and quantum discord
Establishing entanglement between distant parties is one of the most
important problems of quantum technology, since long-distance entanglement is
an essential part of such fundamental tasks as quantum cryptography or quantum
teleportation. In this lecture we review basic properties of entanglement and
quantum discord, and discuss recent results on entanglement distribution and
the role of quantum discord therein. We also review entanglement distribution
with separable states, and discuss important problems which still remain open.
One such open problem is a possible advantage of indirect entanglement
distribution, when compared to direct distribution protocols.Comment: 7 pages, 2 figures, contribution to "Lectures on general quantum
correlations and their applications", edited by Felipe Fanchini, Diogo
Soares-Pinto, and Gerardo Adess
The human FK506-binding proteins: characterization of human FKBP19
Analysis of the human repertoire of the FK506-binding protein (FKBP) family of peptidyl-prolyl cis/trans isomerases has identified an expansion of genes that code for human FKBPs in the secretory pathway. There are distinct differences in tissue distribution and expression levels of each variant. In this article we describe the characterization of human FKBP19 (Entrez Gene ID: FKBP11), an FK506-binding protein predominantly expressed in vertebrate secretory tissues. The FKBP19 sequence comprises a cleavable N-terminal signal sequence followed by a putative peptidyl-prolyl cis/trans isomerase domain with homology to FKBP12. This domain binds FK506 weakly in vitro. FKBP19 mRNA is abundant in human pancreas and other secretory tissues and high levels of FKBP19 protein are detected in the acinar cells of mouse pancreas
Quasi-Normal Modes of Stars and Black Holes
Perturbations of stars and black holes have been one of the main topics of
relativistic astrophysics for the last few decades. They are of particular
importance today, because of their relevance to gravitational wave astronomy.
In this review we present the theory of quasi-normal modes of compact objects
from both the mathematical and astrophysical points of view. The discussion
includes perturbations of black holes (Schwarzschild, Reissner-Nordstr\"om,
Kerr and Kerr-Newman) and relativistic stars (non-rotating and
slowly-rotating). The properties of the various families of quasi-normal modes
are described, and numerical techniques for calculating quasi-normal modes
reviewed. The successes, as well as the limits, of perturbation theory are
presented, and its role in the emerging era of numerical relativity and
supercomputers is discussed.Comment: 74 pages, 7 figures, Review article for "Living Reviews in
Relativity
Community ecology of the Middle Miocene primates of La Venta, Colombia: the relationship between ecological diversity, divergence time, and phylogenetic richness
It has been suggested that the degree of ecological diversity that characterizes a primate community correlates positively with both its phylogenetic richness and the time since the members of that community diverged (Fleagle and Reed in Primate communities. Cambridge University Press, New York, pp 92–115, 1999). It is therefore questionable whether or not a community with a relatively recent divergence time but high phylogenetic richness would be as ecologically variable as a community with similar phylogenetic richness but a more distant divergence time. To address this question, the ecological diversity of a fossil primate community from La Venta, Colombia, a Middle Miocene platyrrhine community with phylogenetic diversity comparable with extant platyrrhine communities but a relatively short time since divergence, was compared with that of modern Neotropical primate communities. Shearing quotients and molar lengths, which together are reliable indicators of diet, for both fossil and extant species were plotted against each other to describe the dietary “ecospace” occupied by each community. Community diversity was calculated as the area of the minimum convex polygon encompassing all community members. The diversity of the fossil community was then compared with that of extant communities to test whether the fossil community was less diverse than extant communities while taking phylogenetic richness into account. Results indicate that the La Ventan community was not significantly less ecologically diverse than modern communities, supporting the idea that ecological diversification occurred along with phylogenetic diversification early in platyrrhine evolution
Identifying characteristic features of the retinal and choroidal vasculature in choroideremia using optical coherence tomography angiography
PURPOSE: Using optical coherence tomography angiography (OCTA) to investigate the area with flow in the superficial retinal vessel network (SVRN) and choriocapillaris (CC) layer among male subjects with choroideremia (CHM), female carriers, and normal controls to identify vascular changes. PATIENTS AND METHODS: Images of SRVN and CC layer were acquired in 9 affected males, 5 female carriers, and 14 age- and gender-matched controls using the Angiovue software of the RTVue XR Avanti. RESULTS: The mean age was 33 years for affected male CHM patients (median 30 years), 46 years for female carriers (median 53 years), and 39 years for controls (median 38.5). Mean SRVN area±SD in subjects with CHM was 12.93±2.06 mm², in carrier subjects 15.36±0.60 mm², and in controls 15.30±1.35 mm² (P<0.01). The mean CC area±SD with flow was 6.97±5.26 mm² in CHM subjects, 21.65±0.17 mm² in carriers and 21.36±0.76 mm² in controls (P<0.01). SRVN and CC area with flow showed a negative correlation in CHM subjects with the age (r=−0.86; P<0.003 and r=−0.77; P<0.01, respectively). CC area with flow had a positive correlation with SRVN (r=0.83, P<0.001). Overall, visual acuity had a negative correlation with SRVN and CC area with flow (r=−0.67, P<0.001 and r=−0.57, P<0.002, respectively). CONCLUSIONS: This is the first study to highlight changes in the SRVN in CHM subjects. OCTA detected a reduced area with flow in both retinal and choroidal circulations, and may be a useful tool for monitoring natural history and disease progression in forthcoming clinical trials
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