128 research outputs found
Variations on the Theme of Journe's Lemma
Journe's Lemma is a critical component of many questions related to the
product theory of S.-Y. Chang and R. Fefferman. This article presents
several different variants of the Lemma, some known, some implicit in the
literature, and some new.Comment: 27 pages ; 17 references; To appear in Houston Journal of Mathematic
A Compact Representation of Histopathology Images using Digital Stain Separation & Frequency-Based Encoded Local Projections
In recent years, histopathology images have been increasingly used as a
diagnostic tool in the medical field. The process of accurately diagnosing a
biopsy sample requires significant expertise in the field, and as such can be
time-consuming and is prone to uncertainty and error. With the advent of
digital pathology, using image recognition systems to highlight problem areas
or locate similar images can aid pathologists in making quick and accurate
diagnoses. In this paper, we specifically consider the encoded local
projections (ELP) algorithm, which has previously shown some success as a tool
for classification and recognition of histopathology images. We build on the
success of the ELP algorithm as a means for image classification and
recognition by proposing a modified algorithm which captures the local
frequency information of the image. The proposed algorithm estimates local
frequencies by quantifying the changes in multiple projections in local windows
of greyscale images. By doing so we remove the need to store the full
projections, thus significantly reducing the histogram size, and decreasing
computation time for image retrieval and classification tasks. Furthermore, we
investigate the effectiveness of applying our method to histopathology images
which have been digitally separated into their hematoxylin and eosin stain
components. The proposed algorithm is tested on the publicly available invasive
ductal carcinoma (IDC) data set. The histograms are used to train an SVM to
classify the data. The experiments showed that the proposed method outperforms
the original ELP algorithm in image retrieval tasks. On classification tasks,
the results are found to be comparable to state-of-the-art deep learning
methods and better than many handcrafted features from the literature.Comment: Accepted for publication in the International Conference on Image
Analysis and Recognition (ICIAR 2019
[μ-1,3-Bis(diphenylphosphino)propane-κ2 P:P′]bis[bromidogold(I)]
The title compound, [Au2Br2(C27H26P2)], features linearly coordinated AuI atoms within P,Br-donor sets. The central portion of the molecule is practically planar as quantified by the Br–Au⋯Au–Br torsion angle of −169.9 (2)°. The P—Au—Br chromophores are twisted with respect to each other [dihedral angle = 52.3 (6)°]. The benzene rings on each P atom lie on either side of this plane. The Au atoms are positioned at the periphery of the molecule, which facilitates the formation of Au⋯Au interactions [3.2575 (11) Å] that result in the formation of supramolecular chains along the b-axis direction. The Au⋯Au interactions are responsible for the deviations from the ideal linear geometry for each Au atom
Finding secluded places of special interest in graphs.
Finding a vertex subset in a graph that satisfies a certain property is one of the most-studied topics
in algorithmic graph theory. The focus herein is often on minimizing or maximizing the size
of the solution, that is, the size of the desired vertex set. In several applications, however, we also
want to limit the “exposure” of the solution to the rest of the graph. This is the case, for example,
when the solution represents persons that ought to deal with sensitive information or a segregated
community. In this work, we thus explore the (parameterized) complexity of finding such secluded
vertex subsets for a wide variety of properties that they shall fulfill. More precisely, we study the
constraint that the (open or closed) neighborhood of the solution shall be bounded by a parameter
and the influence of this constraint on the complexity of minimizing separators, feedback vertex
sets, F-free vertex deletion sets, dominating sets, and the maximization of independent sets
Finding secluded places of special interest in graphs
Finding a vertex subset in a graph that satisfies a certain property is one of the most-studied topics in algorithmic graph theory. The focus herein is often on minimizing or maximizing the size of the solution, that is, the size of the desired vertex set. In several applications, however, we also want to limit the “exposure” of the solution to the rest of the graph. This is the case, for example, when the solution represents persons that ought to deal with sensitive information or a segregated community. In this work, we thus explore the (parameterized) complexity of finding such secluded vertex subsets for a wide variety of properties that they shall fulfill. More precisely, we study the constraint that the (open or closed) neighborhood of the solution shall be bounded by a parameter and the influence of this constraint on the complexity of minimizing separators, feedback vertex sets, F-free vertex deletion sets, dominating sets, and the maximization of independent sets
Recommended from our members
Unitized regenerative fuel cell systems
Energy storage systems with extremely high specific energy (>400 Wh/kg) have been designed that use lightweight pressure vessels to contain the gases generated by reversible (unitized) regenerative fuel cells (URFCs).[1] URFC systems are being designed and developed for a variety of applications, including high altitude long endurance (HALE) solar rechargeable aircraft (SRA), zero emission vehicles (ZEVs), hybrid energy storage/propulsion systems for spacecraft, energy storage for remote (off-grid) power sources, and peak shaving for on-grid applications.[1-10] Energy storage for HALE SRA was the original application for this set of innovations, and a prototype solar powered aircraft (Pathfinder-Plus) recently set another altitude record for all propeller-driven aircraft on August 6, 1998, when it flew to 80,285 feet (24.47 km).[11
Metamaterial Polarization Converter Analysis: Limits of Performance
In this paper we analyze the theoretical limits of a metamaterial converter
that allows for linear-to- elliptical polarization transformation with any
desired ellipticity and ellipse orientation. We employ the transmission line
approach providing a needed level of the design generalization. Our analysis
reveals that the maximal conversion efficiency for transmission through a
single metamaterial layer is 50%, while the realistic re ection configuration
can give the conversion efficiency up to 90%. We show that a double layer
transmission converter and a single layer with a ground plane can have 100%
polarization conversion efficiency. We tested our conclusions numerically
reaching the designated limits of efficiency using a simple metamaterial
design. Our general analysis provides useful guidelines for the metamaterial
polarization converter design for virtually any frequency range of the
electromagnetic waves.Comment: 10 pages, 11 figures, 2 table
Working memory dynamics and spontaneous activity in a flip-flop oscillations network model with a Milnor attractor
Many cognitive tasks require the ability to maintain and manipulate simultaneously several chunks of information. Numerous neurobiological observations have reported that this ability, known as the working memory, is associated with both a slow oscillation (leading to the up and down states) and the presence of the theta rhythm. Furthermore, during resting state, the spontaneous activity of the cortex exhibits exquisite spatiotemporal patterns sharing similar features with the ones observed during specific memory tasks. Here to enlighten neural implication of working memory under these complicated dynamics, we propose a phenomenological network model with biologically plausible neural dynamics and recurrent connections. Each unit embeds an internal oscillation at the theta rhythm which can be triggered during up-state of the membrane potential. As a result, the resting state of a single unit is no longer a classical fixed point attractor but rather the Milnor attractor, and multiple oscillations appear in the dynamics of a coupled system. In conclusion, the interplay between the up and down states and theta rhythm endows high potential in working memory operation associated with complexity in spontaneous activities
Families of patients in ICU: A Scoping review of their needs and satisfaction with care
Aim To describe published literature on the needs and experiences of family members of adults admitted to intensive care and interventions to improve family satisfaction and psychological well‐being and health. Design Scoping review. Methods Several selective databases were searched. English‐language articles were retrieved, and data extracted on study design, sample size, sample characteristics and outcomes measured. Results From 469 references, 43 studies were identified for inclusion. Four key themes were identified: (a) Different perspectives on meeting family needs; (b) Family satisfaction with care in intensive care; (c) Factors having an impact on family health and well‐being and their capacity to cope; and (d) Psychosocial interventions. Unmet informational and assurance needs have an impact on family satisfaction and mental health. Structured written and oral information shows some effect in improving satisfaction and reducing psychological burden. Future research might include family in the design of interventions, provide details of the implementation process and have clearly identified outcomes
Practical, Microfabrication-Free Device for Single-Cell Isolation
Microfabricated devices have great potential in cell-level studies, but are not easily accessible for the broad biology community. This paper introduces the Microscale Oil-Covered Cell Array (MOCCA) as a low-cost device for high throughput single-cell analysis that can be easily produced by researchers without microengineering knowledge. Instead of using microfabricated structures to capture cells, MOCCA isolates cells in discrete aqueous droplets that are separated by oil on patterned hydrophilic areas across a relatively more hydrophobic substrate. The number of randomly seeded Escherichia coli bacteria in each discrete droplet approaches single-cell levels. The cell distribution on MOCCA is well-fit with Poisson distribution. In this pioneer study, we created an array of 900-picoliter droplets. The total time needed to seed cells in ∼3000 droplets was less than 10 minutes. Compared to traditional microfabrication techniques, MOCCA dramatically lowers the cost of microscale cell arrays, yet enhances the fabrication and operational efficiency for single-cell analysis
- …