6,608 research outputs found
How to project a bipartite network?
The one-mode projecting is extensively used to compress the bipartite
networks. Since the one-mode projection is always less informative than the
bipartite representation, a proper weighting method is required to better
retain the original information. In this article, inspired by the network-based
resource-allocation dynamics, we raise a weighting method, which can be
directly applied in extracting the hidden information of networks, with
remarkably better performance than the widely used global ranking method as
well as collaborative filtering. This work not only provides a creditable
method in compressing bipartite networks, but also highlights a possible way
for the better solution of a long-standing challenge in modern information
science: How to do personal recommendation?Comment: 7 pages, 4 figure
Irreversible proliferation of magnetic moments at cleaved surfaces of the topological Kondo insulator SmB6
The compound SmB is the best established realization of a topological
Kondo insulator, in which a topological insulator state is obtained through
Kondo coherence. Recent studies have found evidence that the surface of SmB
hosts ferromagnetic domains, creating an intrinsic platform for unidirectional
ballistic transport at the domain boundaries. Here, surface-sensitive X-ray
absorption (XAS) and bulk-sensitive resonant inelastic X-ray scattering (RIXS)
spectra are measured at the Sm N-edge, and used to evaluate electronic
symmetries, excitations and temperature dependence near the surface of cleaved
samples. The XAS data show that the density of large-moment atomic multiplet
states on a cleaved surface grows irreversibly over time, to a degree that
likely exceeds a related change that has recently been observed in the surface
4f orbital occupation
Ecology & computer audition: applications of audio technology to monitor organisms and environment
Among the 17 Sustainable Development Goals (SDGs) proposed within the 2030 Agenda and adopted by all the United Nations member states, the 13th SDG is a call for action to combat climate change. Moreover, SDGs 14 and 15 claim the protection and conservation of life below water and life on land, respectively. In this work, we provide a literature-founded overview of application areas, in which computer audition – a powerful but in this context so far hardly considered technology, combining audio signal processing and machine intelligence – is employed to monitor our ecosystem with the potential to identify ecologically critical processes or states. We distinguish between applications related to organisms, such as species richness analysis and plant health monitoring, and applications related to the environment, such as melting ice monitoring or wildfire detection. This work positions computer audition in relation to alternative approaches by discussing methodological strengths and limitations, as well as ethical aspects. We conclude with an urgent call to action to the research community for a greater involvement of audio intelligence methodology in future ecosystem monitoring approaches
Impact of patient characteristics on the risk of influenza/ILI-related complications
BACKGROUND: We sought to quantify the impact of patient characteristics on complications and health care costs associated with influenza and influenza-like illness (ILI) in a nonelderly population. METHODS: Patients with medical reimbursement claims for influenza in the 1996–1997 season were identified from the automated database of a large private New England Insurer (NEI). Influenza care during the 21- day follow-up period was characterized according to age, gender, vaccine status, co-morbidities, prior influenza/ILI episodes, treatments, and recent health care costs and related diagnoses. RESULTS: There were 6,241 patients. Approximately 20% had preexisting chronic lung disease. Overall, 23% had health care services for possible complications, among which respiratory diagnoses were the most common (13%). Two percent of the influenza/ILI episodes involved hospitalization, with a median stay of five days. Factors most strongly predictive of hospitalizations and complications were preexisting malignancy (hospitalizations OR = 3.7 and complications OR = 2.4), chronic heart disease (OR = 3.2 and OR = 1.8), diabetes (OR = 2.2 and OR = 1.7) and recent illnesses that would have counted as complications had they occurred during an influenza/ILI episode (hospitalizations OR = 3.2 and complications OR = 1.5). The same factors affected influenza-related costs and total costs of care as dramatically as they affected complication rates. CONCLUSIONS: Influenza/ILI-related costs are driven by the characteristics that predict complications of influenza. Patients with chronic illness and those with recent acute respiratory events are the most likely to experience complications and hospitalizations
A frequency-domain perspective on GW150914 ringdown overtone
We revisit the recent debate on the evidence for an overtone in the black
hole ringdown of GW150914. By gating and inpainting the data, we discard the
contamination from earlier parts of the gravitational wave signal before
ringdown. This enables the parameter estimation to be conducted in the
frequency domain, which is mathematically equivalent to the time domain method.
We keep the settings as similar as possible to the previous studies by
\textcite{Cotesta:2022pci} and Isi \textit{et
al.}\cite{Isi:2019aib,Isi:2022mhy} which yielded conflicting results on the
Bayes factor of the overtone. We examine the spectral contents of the
matched-filtering in the frequency domain, and propose a convergence test to
assess the validity of an overtone model. Our results find the Bayes factors
for the overtone fall within and around a range of times centered at
the best-fit merger time of GW150914, which supports the existence of an
overtone in agreement with the conclusions of Isi \textit{et
al.}\cite{Isi:2019aib,Isi:2022mhy}. Our work contributes to the understanding
of how various methods affect the statistical significance of overtones.Comment: 8 pages, 7 figures. Data release at
https://github.com/gwastro/gw150914-overtone. Comments welcome
Spectroscopy for asymmetric binary black hole mergers
We study Bayesian inference of black hole ringdown modes for simulated binary black hole signals. We consider to what extent different fundamental ringdown modes can be identified in the context of black hole spectroscopy. Our simulated signals are inspired by the high-mass event GW190521. We find strong correlation between mass ratio and Bayes factors of the subdominant ringdown modes. The Bayes factor values and time dependency, and the peak time of the (3,3,0) mode align with those found analyzing the real event GW190521, particularly for high-mass ratio systems
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Computational cytometer based on magnetically modulated coherent imaging and deep learning.
Detecting rare cells within blood has numerous applications in disease diagnostics. Existing rare cell detection techniques are typically hindered by their high cost and low throughput. Here, we present a computational cytometer based on magnetically modulated lensless speckle imaging, which introduces oscillatory motion to the magnetic-bead-conjugated rare cells of interest through a periodic magnetic force and uses lensless time-resolved holographic speckle imaging to rapidly detect the target cells in three dimensions (3D). In addition to using cell-specific antibodies to magnetically label target cells, detection specificity is further enhanced through a deep-learning-based classifier that is based on a densely connected pseudo-3D convolutional neural network (P3D CNN), which automatically detects rare cells of interest based on their spatio-temporal features under a controlled magnetic force. To demonstrate the performance of this technique, we built a high-throughput, compact and cost-effective prototype for detecting MCF7 cancer cells spiked in whole blood samples. Through serial dilution experiments, we quantified the limit of detection (LoD) as 10 cells per millilitre of whole blood, which could be further improved through multiplexing parallel imaging channels within the same instrument. This compact, cost-effective and high-throughput computational cytometer can potentially be used for rare cell detection and quantification in bodily fluids for a variety of biomedical applications
Parameters of Herbig Ae/Be and Vega-type stars
This work presents the determination of the effective temperature, gravity,
metallicity, mass, luminosity and age of 27 young early-type stars, most of
them in the age range 1-10 Myr, and three -suspected- hot companions of post-T
Tauri stars belonging to the Lindroos binary sample. Most of these objects show
IR excesses in their spectral energy distributions, which are indicative of the
presence of disks. The work is relevant in the fields of stellar physics,
physics of disks and formation of planetary systems.
Spectral energy distributions and mid-resolution spectra were used to
estimate the effective temperature. The comparison of the profiles of the
Balmer lines with synthetic profiles provides the value of the stellar gravity.
High-resolution optical observations and synthetic spectra are used to estimate
the metallicity, [M/H]. Once these three parameters are known for each star,
evolutionary tracks and isochrones provide estimations of the mass, luminosity,
age and distance (or upper limits in some cases). The method is original in the
sense that it is distance-independent, i.e. the estimation of the stellar
parameters does not require, as it happens in other works, the knowledge of the
distance to the object. A detailed discussion on some individual objects, in
particular VV Ser, RR Tau, 49 Cet and the three suspected hot companions of
post-T Tauris, is presented. The paper also shows the difficulty posed by the
morphology and behaviour of the system star+disk in the computation of the
stellar parameters.Comment: 18 pages, 11 figure
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