1,013 research outputs found
Electrostatic Field Classifier for Deficient Data
This paper investigates the suitability of recently developed models based on the physical
field phenomena for classification problems with incomplete datasets. An original approach
to exploiting incomplete training data with missing features and labels, involving extensive use
of electrostatic charge analogy, has been proposed. Classification of incomplete patterns has been
investigated using a local dimensionality reduction technique, which aims at exploiting all available
information rather than trying to estimate the missing values. The performance of all proposed
methods has been tested on a number of benchmark datasets for a wide range of missing data scenarios
and compared to the performance of some standard techniques. Several modifications of the
original electrostatic field classifier aiming at improving speed and robustness in higher dimensional
spaces are also discussed
Compressed correlation functions and fast aging dynamics in metallic glasses
We present x-ray photon correlation spectroscopy measurements of the atomic
dynamics in a Zr67Ni33 metallic glass, well below its glass transition
temperature. We find that the decay of the density fluctuations can be well
described by compressed, thus faster than exponential, correlation functions
which can be modeled by the well-known Kohlrausch-Williams-Watts function with
a shape exponent {\beta} larger than one. This parameter is furthermore found
to be independent of both waiting time and wave-vector, leading to the
possibility to rescale all the correlation functions to a single master curve.
The dynamics in the glassy state is additionally characterized by different
aging regimes which persist in the deep glassy state. These features seem to be
universal in metallic glasses and suggest a non diffusive nature of the
dynamics. This universality is supported by the possibility of describing the
fast increase of the structural relaxation time with waiting time using a
unique model function, independently of the microscopic details of the system.Comment: 7 pages, 4 figures. To be published in J. Chem. Phy
AGN feedback with the Square Kilometer Array (SKA) and implications for cluster physics and cosmology
AGN feedback is regarded as an important non-gravitational process in galaxy
clusters, providing useful constraints on large-scale structure formation. It
modifies the structure and energetics of the intra-cluster medium (ICM) and
hence its understanding is crucially needed in order to use clusters as high
precision cosmological probes. In this context, particularly keeping in mind
the upcoming high quality radio data expected from radio surveys like SKA with
its higher sensitivity, high spatial and spectral resolutions, we review our
current understanding of AGN feedback, its cosmological implications and the
impact that SKA can have in revolutionizing our understanding of AGN feedback
in large-scale structures. Recent developments regarding the AGN outbursts and
its possible contribution to excess entropy in the hot atmospheres of groups
and clusters, its correlation with the feedback energy in ICM, quenching of
cooling flows and the possible connection between cool core clusters and radio
mini-halos, are discussed. We describe current major issues regarding modeling
of AGN feedback and its impact on the surrounding medium. With regard to the
future of AGN feedback studies, we examine the possible breakthroughs that can
be expected from SKA observations. In the context of cluster cosmology, for
example, we point out the importance of SKA observations for cluster mass
calibration by noting that most of clusters discovered by eROSITA X-ray
mission can be expected to be followed up through a 1000 hour SKA-1 mid
programme. Moreover, approximately radio mini halos and
radio halos at can be potentially detected by SKA1 and SKA2 and used as
tracers of galaxy clusters and determination of cluster selection function.Comment: 14 pages, 10 figures, Review article accepted in Journal of
Astrophysics and Astronomy (JOAA
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Elevated fetal steroidogenic activity in autism
Autism affects males more than females, giving rise to the idea that the influence of steroid hormones on early fetal brain development may be one important early biological risk factor. Utilizing the Danish Historic Birth Cohort and Danish Psychiatric Central Register, we identified all amniotic fluid samples of males born between 1993 and 1999 who later received ICD-10 (International Classification of Diseases, 10th Revision) diagnoses of autism, Asperger syndrome or PDD-NOS (pervasive developmental disorder not otherwise specified) (n=128) compared with matched typically developing controls. Concentration levels of Δ4 sex steroids (progesterone, 17α-hydroxy-progesterone, androstenedione and testosterone) and cortisol were measured with liquid chromatography tandem mass spectrometry. All hormones were positively associated with each other and principal component analysis confirmed that one generalized latent steroidogenic factor was driving much of the variation in the data. The autism group showed elevations across all hormones on this latent generalized steroidogenic factor (Cohen's d=0.37, P=0.0009) and this elevation was uniform across ICD-10 diagnostic label. These results provide the first direct evidence of elevated fetal steroidogenic activity in autism. Such elevations may be important as epigenetic fetal programming mechanisms and may interact with other important pathophysiological factors in autism
Our Apples are Healthier than Your Apples: Deciphering the Healthiness Bias for Domestic and Foreign Products
This study extends previous research by exploring perceptions of healthiness in the international food marketplace. To this end, it aims to fill an important gap by shedding light on the role of country of origin in shaping perceptions of healthiness. The authors provide evidence that domestic and foreign food products elicit different perceptions of healthiness. Consumers choose domestic products because they perceive them as healthier and more natural. The effect holds across different samples and product categories (apples, tomatoes, bread, and yogurt). However, this healthiness bias vanishes when products are presented as posing health risks and when products are introduced with a dual identity (i.e., both foreign and domestic). Researching these health-related effects helps provide a better understanding of consumer attitudes toward domestic- versus foreign-made food products
The Value of Literacy Practices
The concepts of literacy events and practices have received considerable attention in educational research and policy. In comparison, the question of value, that is, ‘which literacy practices do people most value?’ has been neglected. With the current trend of cross-cultural adult literacy assessment, it is increasingly important to recognise locally valued literacy practices. In this paper we argue that measuring preferences and weighting of literacy practices provides an empirical and democratic basis for decisions in literacy assessment and curriculum development and could inform rapid educational adaptation to changes in the literacy environment. The paper examines the methodological basis for investigating literacy values and its potential to inform cross-cultural literacy assessments. The argument is illustrated with primary data from Mozambique. The correlation between individual values and respondents’ socio-economic and demographic characteristics is explored
Revealing the fast atomic motion of network glasses
Still very little is known on the relaxation dynamics of glasses at the microscopic level due to the lack of experiments and theories. It is commonly believed that glasses are in a dynamical arrested state, with relaxation times too large to be observed on human time scales. Here we provide the experimental evidence that glasses display fast atomic rearrangements within a few minutes, even in the deep glassy state. Following the evolution of the structural relaxation in a sodium silicate glass, we find that this fast dynamics is accompanied by the absence of any detectable aging, suggesting a decoupling of the relaxation time and the viscosity in the glass. The relaxation time is strongly affected by the network structure with a marked increase at the mesoscopic scale associated with the ion-conducting pathways. Our results modify the conception of the glassy state and asks for a new microscopic theory
Consensus definitions of 14 severe acute toxic effects for childhood lymphoblastic leukaemia treatment: a Delphi consensus
Although there are high survival rates for children with acute lymphoblastic leukaemia, their outcome is often counterbalanced by the burden of toxic effects. This is because reported frequencies vary widely across studies, partly because of diverse definitions of toxic effects. Using the Delphi method, 15 international childhood acute lymphoblastic leukaemia study groups assessed acute lymphoblastic leukaemia protocols to address toxic effects that were to be considered by the Ponte di Legno working group. 14 acute toxic effects (hypersensitivity to asparaginase, hyperlipidaemia, osteonecrosis, asparaginase-associated pancreatitis, arterial hypertension, posterior reversible encephalopathy syndrome, seizures, depressed level of consciousness, methotrexate-related stroke-like syndrome, peripheral neuropathy, high-dose methotrexate-related nephrotoxicity, sinusoidal obstructive syndrome, thromboembolism, and Pneumocystis jirovecii pneumonia) that are serious but too rare to be addressed comprehensively within any single group, or are deemed to need consensus definitions for reliable incidence comparisons, were selected for assessment. Our results showed that none of the protocols addressed all 14 toxic effects, that no two protocols shared identical definitions of all toxic effects, and that no toxic effect definition was shared by all protocols. Using the Delphi method over three face-to-face plenary meetings, consensus definitions were obtained for all 14 toxic effects. In the overall assessment of outcome of acute lymphoblastic leukaemia treatment, these expert opinion-based definitions will allow reliable comparisons of frequencies and severities of acute toxic effects across treatment protocols, and facilitate international research on cause, guidelines for treatment adaptation, preventive strategies, and development of consensus algorithms for reporting on acute lymphoblastic leukaemia treatment
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