95 research outputs found
Bistable molecular conductors with a field-switchable dipole group
A class of bistable "stator-rotor" molecules is proposed, where a stationary
bridge (stator) connects the two electrodes and facilitates electron transport
between them. The rotor part, which has a large dipole moment, is attached to
an atom of the stator via a single sigma bond. Hydrogen bonds formed between
the rotor and stator make the symmetric orientation of the dipole unstable. The
rotor has two potential minima with equal energy for rotation about the sigma
bond. The dipole orientation, which determines the conduction state of the
molecule, can be switched by an external electric field that changes the
relative energy of the two potential minima. Both orientation of the rotor
correspond to asymmetric current-voltage characteristics that are the reverse
of each other, so they are distinguishable electrically. Such bistable
stator-rotor molecules could potentially be used as parts of molecular
electronic devices.Comment: 8 pages, 7 figure
The Troubling Epidemic of Wife-Battering in Ogbaru and Onitsha North Local Government Areas of Anambra State, Nigeria
Purpose: Debates and assumptions on the trend, motives/causes and implications of wife-battering in Nigeria are largely speculative. The purpose of this article is to explore in a raw form, the socio-economic determinants of wife-battering, on the sub-areas of family violence.
Methods: Using qualitative and quantitative research methods, a sample of 364 respondents comprising 196 males and 168 females was drawn from Anambra State, Nigeria. Multi-stage and purposive sampling techniques were used to reach the respondents. Questionnaire and in-depth interviews were instruments for data collection.
Results: Findings confirmed that wife-battering in Ogbaru and Onitsha-North Local Government Areas is most often caused by denial of sex and infidelity.
Conclusion: The policy implications calls for the creation of local government welfare units to be holding periodic talk shows for married couples on the imperative of living happily
ICTV Virus Taxonomy Profile:Coronaviridae 2023
The family Coronaviridae includes viruses with positive-sense RNA genomes of 22-36 kb that are expressed through a nested set of 3' co-terminal subgenomic mRNAs. Members of the subfamily Orthocoronavirinae are characterized by 80-160 nm diameter, enveloped virions with spike projections. The orthocoronaviruses, severe acute respiratory syndrome coronavirus and Middle East respiratory syndrome-related coronavirus are extremely pathogenic for humans and in the last two decades have been responsible for the SARS and MERS epidemics. Another orthocoronavirus, severe acute respiratory syndrome coronavirus 2, was responsible for the recent global COVID-19 pandemic. This is a summary of the International Committee on Taxonomy of Viruses (ICTV) Report on the family Coronaviridae which is available at www.ictv.global/report/coronaviridae.</p
Optimization of Network Topology in Computer-Aided Detection Schemes Using Phased Searching with NEAT in a Time-Scaled Framework
In the field of computer-aided mammographic mass detection, many different features and classifiers have been tested. Frequently, the relevant features and optimal topology for the artificial neural network (ANN)-based approaches at the classification stage are unknown, and thus determined by trial-and-error experiments. In this study, we analyzed a classifier that evolves ANNs using genetic algorithms (GAs), which combines feature selection with the learning task. The classifier named âPhased Searching with NEAT in a Time-Scaled Frameworkâ was analyzed using a dataset with 800 malig-nant and 800 normal tissue regions in a 10-fold cross-validation framework. The classification performance measured by the area under a receiver operating characteristic (ROC) curve was 0.856 ± 0.029. The result was also compared with four other well-established classifiers that include fixed-topology ANNs, support vector machines (SVMs), linear discriminant analysis (LDA), and bagged decision trees. The results show that Phased Searching outperformed the LDA and bagged decision tree classifiers, and was only significantly outperformed by SVM. Furthermore, the Phased Searching method required fewer features and discarded superfluous structure or topology, thus incurring a lower feature computational and training and validation time requirement. Analyses performed on the network complexities evolved by Phased Searching indicate that it can evolve optimal network topologies based on its complexi-fication and simplification parameter selection process. From the results, the study also concluded that the three classifiers â SVM, fixed-topology ANN, and Phased Searching with NeuroEvolution of Augmenting Topologies (NEAT) in a Time-Scaled Framework â are performing comparably well in our mammographic mass detection scheme.Ye
Endothelial cell dysfunction: Implications for the pathogenesis of peripheral artery disease
Peripheral artery disease (PAD) is caused by occluded or narrowed arteries that reduce blood flow to the lower limbs. The treatment focuses on lifestyle changes, management of modifiable risk factors and vascular surgery. In this review we focus on how Endothelial Cell (EC) dysfunction contributes to PAD pathophysiology and describe the largely untapped potential of correcting endothelial dysfunction. Moreover, we describe current treatments and clinical trials which improve EC dysfunction and offer insights into where future research efforts could be made. Endothelial dysfunction could represent a target for PAD therapy.Mary M. Kavurma, Christina Bursill, Christopher P. Stanley, Freda Passam, SiĂąn P. Cartland, Sanjay Patel, Jacky Loa, Gemma A. Figtree, Jonathan Golledge, Sarah Aitken, and David A. Robinso
Derivative moments for characteristic polynomials from the CUE
We calculate joint moments of the characteristic polynomial of a random
unitary matrix from the circular unitary ensemble and its derivative in the
case that the power in the moments is an odd positive integer. The calculations
are carried out for finite matrix size and in the limit as the size of the
matrices goes to infinity. The latter asymptotic calculation allows us to prove
a long-standing conjecture from random matrix theory.Comment: 31 pages, 3 figure
Avaliação de 67 casos de protrusão da glùndula da terceira pålpebra em cães (2005-2010)
Calabi-Yau Volumes and Reflexive Polytopes
We study various geometrical quantities for CalabiâYau varieties realized as cones over Gorenstein Fano varieties, obtained as toric varieties from reflexive polytopes in various dimensions. Focus is made on reflexive polytopes up to dimension 4 and the minimized volumes of the SasakiâEinstein base of the corresponding CalabiâYau cone are calculated. By doing so, we conjecture new bounds for the SasakiâEinstein volume with respect to various topological quantities of the corresponding toric varieties. We give interpretations about these volume bounds in the context of associated field theories via the AdS/CFT correspondence
Model-independent measurement of -channel single top quark production in collisions at TeV
We present a model-independent measurement of -channel electroweak
production of single top quarks in \ppbar collisions at . Using of integrated luminosity collected by the D0
detector at the Fermilab Tevatron Collider, and selecting events containing an
isolated electron or muon, missing transverse energy and one or two jets
originating from the fragmentation of quarks, we measure a cross section
\sigma({\ppbar}{\rargap}tqb+X) = 2.90 \pm 0.59\;\rm (stat+syst)\; pb for a
top quark mass of . The probability of the background to
fluctuate and produce a signal as large as the one observed is
, corresponding to a significance of 5.5 standard deviations.Comment: 8 pages, 4 figures, submitted to Phys. Lett.
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