2,501 research outputs found
Open-closed field algebras
We introduce the notions of open-closed field algebra and open-closed field
algebra over a vertex operator algebra V. In the case that V satisfies certain
finiteness and reductivity conditions, we show that an open-closed field
algebra over V canonically gives an algebra over a \C-extension of the
Swiss-cheese partial operad. We also give a tensor categorical formulation and
categorical constructions of open-closed field algebras over V.Comment: 55 pages, largely revised, an old subsection is deleted, a few
references are adde
Degravitation, Inflation and the Cosmological Constant as an Afterglow
In this report, we adopt the phenomenological approach of taking the
degravitation paradigm seriously as a consistent modification of gravity in the
IR, and investigate its consequences for various cosmological situations. We
motivate degravitation-- where Netwon's constant is promoted to a scale
dependent filter function-- as arising from either a small (resonant) mass for
the graviton, or as an effect in semi-classical gravity. After addressing how
the Bianchi identities are to be satisfied in such a set up, we turn our
attention towards the cosmological consequences of degravitation. By
considering the example filter function corresponding to a resonantly massive
graviton (with a filter scale larger than the present horizon scale), we show
that slow roll inflation, hybrid inflation and old inflation remain
quantitatively unchanged. We also find that the degravitation mechanism
inherits a memory of past energy densities in the present epoch in such a way
that is likely significant for present cosmological evolution. For example, if
the universe underwent inflation in the past due to it having tunneled out of
some false vacuum, we find that degravitation implies a remnant `afterglow'
cosmological constant, whose scale immediately afterwards is parametrically
suppressed by the filter scale () in Planck units . We discuss circumstances through which this scenario reasonably
yields the presently observed value for . We also
find that in a universe still currently trapped in some false vacuum state,
resonance graviton models of degravitation only degravitate initially Planck or
GUT scale energy densities down to the presently observed value over timescales
comparable to the filter scale.Comment: To appear in JCAP; sections discussing degravitation as a
semi-classical effect and the modified Bianchi identities adde
Evolution of asexual and sexual reproduction in the aspergilli
Aspergillus nidulans has long-been used as a model organism to gain insights into the genetic basis of asexual and sexual developmental processes both in
other members of the genus Aspergillus, and filamentous fungi in general. Paradigms have been established concerning the regulatory mechanisms of conidial
development. However, recent studies have shown considerable genome divergence in the fungal kingdom, questioning the general applicability of findings from
Aspergillus, and certain longstanding evolutionary theories have been questioned. The phylogenetic distribution of key regulatory elements of asexual reproduction in
A. nidulans was investigated in a broad taxonomic range of fungi. This revealed that some proteins were well conserved in the Pezizomycotina (e.g. AbaA, FlbA, FluG,
NsdD, MedA, and some velvet proteins), suggesting similar developmental roles. However, other elements (e.g. BrlA) had a more restricted distribution solely in the
Eurotiomycetes, and it appears that the genetic control of sporulation seems to be more complex in the aspergilli than in some other taxonomic groups of the
Pezizomycotina. The evolution of the velvet protein family is discussed based on the history of expansion and contraction events in the early divergent fungi. Heterologous expression of the A. nidulans abaA gene in Monascus ruber failed to induce development of complete conidiophores as seen in the aspergilli, but did result in
increased conidial production. The absence of many components of the asexual developmental pathway from members of the Saccharomycotina supports the hypothesis
that differences in the complexity of their spore formation is due in part to the increased diversity of the sporulation machinery evident in the Pezizomycotina. Investigations were also made into the evolution of sex and sexuality in the aspergilli. MAT loci were identified from the heterothallic Aspergillus (Emericella) heterothallicus
and Aspergillus (Neosartorya) fennelliae and the homothallic Aspergillus pseudoglaucus (=Eurotium repens). A consistent architecture of the MAT locus was seen in
these and other heterothallic aspergilli whereas much variation was seen in the arrangement of MAT loci in homothallic aspergilli. This suggested that it is most likely that
the common ancestor of the aspergilli exhibited a heterothallic breeding system. Finally, the supposed prevalence of asexuality in the aspergilli was examined. Investigations were made using A. clavatus as a representative ‘asexual’ species. It was possible to induce a sexual cycle in A. clavatus given the correct MAT1-1 and
MAT1-2 partners and environmental conditions, with recombination confirmed utilising molecular markers. This indicated that sexual reproduction might be possible in
many supposedly asexual aspergilli and beyond, providing general insights into the nature of asexuality in fungi.National Natural Science Foundation of China 31601446National Research Foundation of Korea 2016010945Intelligent Synthetic Biology Center of Global Frontier Projects 2015M3A6A8065838Biotechnology and Biological Sciences Research CouncilGovernment of IraqMinisterio de Economía y Competitividad BIO2015-67148-
Interchannel coupling effects in the spin polarization of energetic photoelectrons
Effects of the interchannel coupling on the spin polarization of energetic
photoelectrons emitted from atomic Ne valence subshells are examined. Like
previously obtained results for cross sections and angular distributions, the
photoelectron spin polarization parameters too are found considerably
influenced by the coupling. The result completes a series of studies to finally
conclude that the independent particle description is inadequate for the {\em
entire} range of photoionization dynamics over the {\em full} spectral energy
domainComment: 7 pages, 5 figures, accepted in Phys. Rev.
Cultural Perspective on Parenting, Trait Emotional Intelligence and Mental Health in Taiwanese Children
The current study aims to clarify the associations as well as the pathways through which parenting and children's emotional intelligence (EI) may influence children's mental health with a cross-sectional sample of 675 school pupils (fourth grade, mean age = 10.4 years, 310 boy, 356 girls and 9 unidentified) in Taiwan. Hierarchical regression and path analyses were used to examine the relationships between parenting styles, children's trait EI, and their psychological symptoms, with children's psychological symptoms as the dependent variable. The results showed that authoritative parenting was positively associated with children‟s trait EI, which in turn had a negative effect on children‟s psychological symptoms, whereas authoritarian and Chinese-specific parenting styles had direct negative effect on children‟s psychological symptoms. These findings shed light on the pathways of the interrelations between different parenting styles, children's trait EI, and psychological symptoms, providing theoretical as well as practical implications for children's emotional development and mental health
Highly Facet-reflection Immune 53GBaud EML for 800G Artificial Intelligence Optical Transceivers
We developed a facet-reflection immune 53GBaud electro-absorption modulated laser (EML) for 800G artificial intelligence (AI) optical network. An ultra-low anti-reflection (AR) coating reflectivity of 2x10-5 has been demonstrated for straight waveguide. Based on Hakki-Paoli method, we characterized the ultra-low AR using the ripple test technique. Such ultra-low AR is critical in achieving excellent eye pattern and optical transmission for 800G AI supercomputing
A microsatellite marker for yellow rust resistance in wheat
Bulk segregant analysis (BSA) was used to identify molecular markers associated with yellow rust disease resistance in wheat (Triticum aestivum L.). DNAs isolated from the selected yellow rust tolerant and susceptible F-2 individuals derived from a cross between yellow rust resistant and susceptible wheat genotypes were used to established a "tolerant" and a "susceptible" DNA pool. The BSA was then performed on these DNA pools using 230 markers that were previously mapped onto the individual wheat chromosomes. One of the SSR markers (Xgwm382) located on chromosome group 2 (A, B, D genomes) was present in the resistant parent and the resistant bulk but not in the susceptible parent and the susceptible bulk, suggesting that this marker is linked to a yellow rust resistance gene. The presence of Xgwm382 was also tested in 108 additional wheat genotypes differing in yellow rust resistance. This analysis showed that 81% of the wheat genotypes known to be yellow rust resistant had the Xgwm382 marker, further suggesting that the presence of this marker correlates with yellow rust resistance in diverse wheat germplasm. Therefore, Xgwm382 could be useful for marker assisted selection of yellow rust resistances genotypes in wheat breeding programs
Muon anomalous magnetic moment and the stabilized Randall-Sundrum scenario
We study the effects of extra dimension on the muon anomalous magnetic moment
in the stabilized Randall-Sundrum scenario. The effects of the Kaluza-Klein
states heavier than the cut-off scale expected to be of order are
neglected. Contribution from the spin-2 Kaluza-Klein states dominates over that
from the spin-0 radion. The recent BNL E821 results impose a strict constraint
on the parameter space of the model: TeV with
. Small is preferred if
is TeV scale.Comment: 9 pages, ReVTeX, reference added, version to appear in PL
Nanoscale III-V Semiconductor Photodetectors for High-Speed Optical Communications
Nanophotonics involves the study of the behavior of light on nanometer scale. Modern nanoscale semiconductor photodetectors are important building blocks for high-speed optical communications. In this chapter, we review the state-of-the-art 2.5G, 10G, and 25G avalanche photodiodes (APDs) that are available in commercial applications. We discuss the key device parameters, including avalanche breakdown voltage, dark current, temperature dependence, bandwidth, and sensitivity. We also present reliability analysis on wear-out degradation and optical/electrical overload stress. We discuss the reliability challenges of nanoscale photodetectors associated with device miniaturization for the future. The reliability aspects in terms of high electric field, Joule heating, and geometry inhomogeneity are highlighted
Leading Isgur-Wise form factor of transition using QCD sum rules
The leading Isgur-Wise form factor parametrizing the semileptonic
transitions and
is calculated by using the QCD sum
rules in the framework of heavy quark effective theory, where
and is the orbitally excited charmed
baryon doublet with . The interpolating currents with
transverse covariant derivative are adopted for and
in the analysis. The slope parameter in linear
approximation of the Isgur-Wise function is obtained to be , and
the interception to be . The decay branching ratios are estimated.Comment: 16 pages, 3 figures, to appear in PL
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