2,755 research outputs found
General Recursion and Formal Topology.
Comment: In Proceedings PAR 2010, arXiv:1012.455
Quantum theory of the low-frequency linear susceptibility of interferometer-type superconducting qubits
We use the density matrix formalism to analyze the interaction of
interferometer-type superconducting qubits with a high quality tank circuit,
which frequency is well below the gap frequency of a qubit. We start with the
ground state characterization of the superconducting flux and charge qubits.
Then, by making use of a dressed state approach we describe the qubits'
spectroscopy when the qubit is irradiated by a microwave field which is tuned
to the gap frequency. The last section of the paper is devoted to continuous
monitoring of qubit states by using a DC SQUID in the inductive mode.Comment: 11 pages, 5 figures; the title and abstract are slightly changed;
several typos are corrected; in order to make our argumentation more clear we
added some comments in the introduction and other section
Morphological and Mitochondrial DNA Analyses of Oysters in the Northern Bay of Bengal, Bangladesh
The geographic boundaries of many important habitat-building shallow estuarine oyster (Family Ostreidae) species are poorly understood, especially in subtropical and tropical waters. These keystone species often have extensive historical and extant ranges, in part because of their ability to adapt to diverse environmental conditions and the transfer and introduction of a few species worldwide for aquaculture production. In addition, oysters exhibit morphological plasticity additionally confounding species identification and taxonomy. Molecular techniques have led to significant improvements in oyster systematics and taxonomy but have not been applied to oysters from many tropical regions, including the coastal areas of the Indian Ocean such as Bangladesh. Because species’ identification based on morphological traits alone, in this case primarily shell characteristics, were inadequate, phylogenetic analyses of mitochondrial cytochrome oxidase subunit I gene fragments was also done to confirm the identity of oyster specimens collected from Bangladesh coastal waters. Phylogenetic analyses of collected oyster samples confirmed the two monophyletic subclades of the Ostreidae family Crassostrea and Saccostrea, and five oyster lineages from the region of Bangladesh were identified: Crassostrea gryphoides, Crassostrea belcheri, Saccostrea cuccullata lineage B, S. cuccullata lineage F, and Saccostrea mordax. A new addition to the list of Crassostrea species, C. belcheri was found in Bangladesh, but C. belcheri, C. gryphoides, and S. cuccullata are considered “common” species in the neighboring states of India and Myanmar indicating a widespread distribution of these species along the entire coast of the Bay of Bengal. However, S. mordax, is a new record for the Bay of Bengal region including the coastal waters of Andaman and Nicobar Islands, and thus extends the geographical distribution of this species
Love, desire, and problematic behaviors : exploring young adults’ smartphone use from a uses and gratifications perspective
In light of the pervasive adoption of smartphones, scholars have explored the consequences of
problematic (i.e., excessive and uncontrolled) use of this technology. Studies have often shown that
individuals who spend much time using smartphones experience symptoms similar to those of
substance addiction. However, considering the number of hours employed on smartphones as a
criterion for measuring problematic use does not account for what people do with their smartphones
and why. This study aims to understand what gratifications are related to smartphone usage time
and problematic use. Secondly, it aims to understand whether different usage profiles are
identifiable from those gratifications and how they differ in terms of problematic use, time-of-use,
and socio-demographic characteristics. The data from 528 Italian university students had been
collected through a cross-sectional design. Through regression analyses, we found that smartphone
gratifications differentially predict the amount of time spent using the smartphone and the level of
problematic use that students exhibited. Using the K-means clustering technique, we identified five
usage profiles that differed in the amount of time spent using smartphones and, to a greater extent,
in their problematic use levels
Saharan dust events at the Jungfraujoch: detection by wavelength dependence of the single scattering albedo and first climatology analysis
International audienceScattering and absorption coefficients have been measured continuously at several wavelengths since March 2001 at the high altitude site Jungfraujoch (3580ma.s.l.). From these data, the wavelength dependences of the Ångström exponent and particularly of the single scattering albedo are determined. While the exponent of the single scattering albedo usually increases with wavelength, it decreases with wavelength during Saharan dust events (SDE) due to the greater size of the mineral aerosol particles and their different chemical composition. This change in the sign of the single scattering exponent turns out to be a sensitive means for detecting Saharan dust events. The occurrence of SDE detected by this new method was confirmed by visual inspection of filter colors and by studying long-range back-trajectories. An examination of SDE over a 22-month period shows that SDE are more frequent during the March-June period as well as during October and November. The trajectory analysis indicated a mean traveling time of 96.5h, with the most important source countries situated in the northern and north-western part of the Saharan desert. Most of the SDE do not lead to a detectable increase of the 48-h total suspended particulate matter (TSP) concentration at the Jungfraujoch. During Saharan dust events, the average contribution of this dust to hourly TSP at the Jungfraujoch is 16µg/m3, which corresponds to an annual mean of 0.8µg/m3 or 24% of TSP
Theoretical and methodological approaches to activism during the COVID-19 pandemic — between continuity and change
In order to understand the way in which scholars approach the study of activism at a time of crisis, a scoping review was conducted to identify the extant empirical work on activism during the COVID-19 crisis. Our search resulted in 23 published papers across disciplines. Results showed elements of continuity and change in scholars' theoretical and empirical approaches to new and old forms of activism emerging at this time of crisis. In general, we found that COVID-19 led to the employment of novel and adaptive approaches from both the activists and the researchers, who tactically modified their strategies in light of the new demands. We conclude by suggesting that incorporating an analysis of the tools of protest, combined with an analysis of the adaptive strategies adopted by communities at a time of crisis might further our understanding of the ontology—as well as the epistemology—of social movements. Moreover, the study highlighted existing tensions between academia and other social stakeholders, which deserve further exploration
Measuring and explaining the diversity of voices and viewpoints in the news
News media can be considered to fulfil their democratic role as a “marketplace of
ideas” only if they present a diverse content that gives space to a wider range of ideas
and viewpoints. But how can content diversity be assessed? And what determines
actor and viewpoint diversity in the first place? By employing measurements of actor
and viewpoint diversity at the article and newspaper level, this study provides a
complete overview on the content diversity of immigration news, and it investigates
factors that have an impact on content diversity of immigration newspaper articles in
Belgium, Germany, Italy and the United Kingdom (2013-2014). The results of a
multilevel analysis indicate that both the articles’ size and the elite character of a
newspaper play a key role in enhancing news’ multiperspectivalness. Also, the
findings show that these two measurements of content diversity are different yet
related to each other
Homeotic genes controlling flower development in Antirrhinum
In order to study genes controlling flower development, we have carried out an extensive transposon-mutagenesis experiment in Antirrhinum majus. More than 15 independent homeotic mutations were obtained, allowing three categories of genes to be defined. The first includes floricaula (flo), a primary gene required for the initiation of the floral developmental pathway. In the absence of the wild-type flo product, proliferating inflorescence meristems arise in place of flowers. The flo gene has been isolated and shown to be expressed transiently in a subset of organ primordia in the floral meristem. The second category includes genes that affect the identity, and also sometimes the number, of whorls of organs in the flower. These genes act in overlapping domains so that each whorl has a distinct combination of gene functions, suggesting a model for the genetic control of whorl identity and number. Genes of the third category control differences between organs in the same whorl and hence the overall symmetry of the flower. We discuss how the basic plan of the flower and inflorescence may arise through the interactions between the three categories of genes
A comparison of collision cross section values obtained via travelling wave ion mobility-mass spectrometry and ultra high performance liquid chromatography-ion mobility-mass spectrometry : application to the characterisation of metabolites in rat urine
A comprehensive Collision Cross Section (CCS) library was obtained via Travelling Wave Ion Guide mobility measurements through direct infusion (DI). The library consists of CCS and Mass Spectral (MS) data in negative and positive ElectroSpray Ionisation (ESI) mode for 463 and 479 endogenous metabolites, respectively. For both ionisation modes combined, TWCCSN2 data were obtained for 542 non-redundant metabolites. These data were acquired on two different ion mobility enabled orthogonal acceleration QToF MS systems in two different laboratories, with the majority of the resulting TWCCSN2 values (from detected compounds) found to be within 1% of one another. Validation of these results against two independent, external TWCCSN2 data sources and predicted TWCCSN2 values indicated to be within 1-2% of these other values. The same metabolites were then analysed using a rapid reversed-phase ultra (high) performance liquid chromatographic (U(H)PLC) separation combined with IM and MS (IM-MS) thus providing retention time (tr), m/z and TWCCSN2 values (with the latter compared with the DI-IM-MS data). Analytes for which TWCCSN2 values were obtained by U(H)PLC-IM-MS showed good agreement with the results obtained from DI-IM-MS. The repeatability of the TWCCSN2 values obtained for these metabolites on the different ion mobility QToF systems, using either DI or LC, encouraged the further evaluation of the U(H)PLC-IM-MS approach via the analysis of samples of rat urine, from control and methotrexate-treated animals, in order to assess the potential of the approach for metabolite identification and profiling in metabolic phenotyping studies. Based on the database derived from the standards 63 metabolites were identified in rat urine, using positive ESI, based on the combination of tr, TWCCSN2 and MS data.</p
An Algebraic Approach to Linear-Optical Schemes for Deterministic Quantum Computing
Linear-Optical Passive (LOP) devices and photon counters are sufficient to
implement universal quantum computation with single photons, and particular
schemes have already been proposed. In this paper we discuss the link between
the algebraic structure of LOP transformations and quantum computing. We first
show how to decompose the Fock space of N optical modes in finite-dimensional
subspaces that are suitable for encoding strings of qubits and invariant under
LOP transformations (these subspaces are related to the spaces of irreducible
unitary representations of U(N)). Next we show how to design in algorithmic
fashion
LOP circuits which implement any quantum circuit deterministically. We also
present some simple examples, such as the circuits implementing a CNOT gate and
a Bell-State Generator/Analyzer.Comment: new version with minor modification
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