758 research outputs found
Federalism to an Advantage: The Demise of State Blue Sky Laws Under the Uniform Securities Act
They come at an opportune time. They are the changes to the Uniform Securities Act. Although some of the changes are perfunctory, the significant changes have a fascinating common thread running through them. That fascinating thread is federalism. Changes in the Act could move regulation away from the hands of the states and make federal registration, more or less, a ticket for sales without state approval. The changes are not without opposition. This article will discuss the changes, the reactions of particular concerned groups and the perceived effects of such changes
Global mapping of RNA homodimers in living cells
RNA homodimerization is important for various physiological processes, including the assembly of membraneless organelles, RNA subcellular localization, and packaging of viral genomes. However, understanding RNA dimerization has been hampered by the lack of systematic in vivo detection methods. Here, we show that CLASH, PARIS, and other RNA proximity ligation methods detect RNA homodimers transcriptome-wide as “overlapping” chimeric reads that contain more than one copy of the same sequence. Analyzing published proximity ligation data sets, we show that RNA:RNA homodimers mediated by direct base-pairing are rare across the human transcriptome, but highly enriched in specific transcripts, including U8 snoRNA, U2 snRNA, and a subset of tRNAs. Mutations in the homodimerization domain of U8 snoRNA impede dimerization in vitro and disrupt zebrafish development in vivo, suggesting an evolutionarily conserved role of this domain. Analysis of virus-infected cells reveals homodimerization of SARS-CoV-2 and Zika genomes, mediated by specific palindromic sequences located within protein-coding regions of N gene in SARS-CoV-2 and NS2A gene in Zika. We speculate that regions of viral genomes involved in homodimerization may constitute effective targets for antiviral therapies
Genome landscapes and bacteriophage codon usage
Across all kingdoms of biological life, protein-coding genes exhibit unequal
usage of synonmous codons. Although alternative theories abound, translational
selection has been accepted as an important mechanism that shapes the patterns
of codon usage in prokaryotes and simple eukaryotes. Here we analyze patterns
of codon usage across 74 diverse bacteriophages that infect E. coli, P.
aeruginosa and L. lactis as their primary host. We introduce the concept of a
`genome landscape,' which helps reveal non-trivial, long-range patterns in
codon usage across a genome. We develop a series of randomization tests that
allow us to interrogate the significance of one aspect of codon usage, such a
GC content, while controlling for another aspect, such as adaptation to
host-preferred codons. We find that 33 phage genomes exhibit highly non-random
patterns in their GC3-content, use of host-preferred codons, or both. We show
that the head and tail proteins of these phages exhibit significant bias
towards host-preferred codons, relative to the non-structural phage proteins.
Our results support the hypothesis of translational selection on viral genes
for host-preferred codons, over a broad range of bacteriophages.Comment: 9 Color Figures, 5 Tables, 53 Reference
Using synthetic biological parts and microbioreactors to explore the protein expression characteristics of Escherichia coli
Synthetic
biology has developed numerous parts for the precise
control of protein expression. However, relatively little is known
about the burden these place on a host, or their reliability under
varying environmental conditions. To address this, we made use of
synthetic transcriptional and translational elements to create a combinatorial
library of constructs that modulated expression strength of a green
fluorescent protein. Combining this library with a microbioreactor
platform, we were able to perform a detailed large-scale assessment
of transient expression and growth characteristics of two <i>Escherichia coli</i> strains across several temperatures. This
revealed significant differences in the robustness of both strains
to differing types of protein expression, and a complex response of
transcriptional and translational elements to differing temperatures.
This study supports the development of reliable synthetic biological
systems capable of working across different hosts and environmental
contexts. Plasmids developed during this work have been made publicly
available to act as a reference set for future research
Pattern Comparator Trigger (PACT) for the muon system of the CMS experiment
The general scheme for the fast, pipelined first level trigger on high pt muons in the CMS detector at LHC is presented. The prototype PACT system was tested in the high momentum muon beams in the RD5 experiment during 1993/94 runs. The obtained efficiency curves are shown
On the appearance of Eisenstein series through degeneration
Let be a Fuchsian group of the first kind acting on the hyperbolic
upper half plane , and let be the
associated finite volume hyperbolic Riemann surface. If is parabolic,
there is an associated (parabolic) Eisenstein series, which, by now, is a
classical part of mathematical literature. If is hyperbolic, then,
following ideas due to Kudla-Millson, there is a corresponding hyperbolic
Eisenstein series. In this article, we study the limiting behavior of parabolic
and hyperbolic Eisenstein series on a degenerating family of finite volume
hyperbolic Riemann surfaces. In particular, we prove the following result. If
corresponds to a degenerating hyperbolic element, then a
multiple of the associated hyperbolic Eisenstein series converges to parabolic
Eisenstein series on the limit surface.Comment: 15 pages, 2 figures. This paper has been accepted for publication in
Commentarii Mathematici Helvetic
Gravitational Waves From Known Pulsars: Results From The Initial Detector Era
We present the results of searches for gravitational waves from a large selection of pulsars using data from the most recent science runs (S6, VSR2 and VSR4) of the initial generation of interferometric gravitational wave detectors LIGO (Laser Interferometric Gravitational-wave Observatory) and Virgo. We do not see evidence for gravitational wave emission from any of the targeted sources but produce upper limits on the emission amplitude. We highlight the results from seven young pulsars with large spin-down luminosities. We reach within a factor of five of the canonical spin-down limit for all seven of these, whilst for the Crab and Vela pulsars we further surpass their spin-down limits. We present new or updated limits for 172 other pulsars (including both young and millisecond pulsars). Now that the detectors are undergoing major upgrades, and, for completeness, we bring together all of the most up-to-date results from all pulsars searched for during the operations of the first-generation LIGO, Virgo and GEO600 detectors. This gives a total of 195 pulsars including the most recent results described in this paper.United States National Science FoundationScience and Technology Facilities Council of the United KingdomMax-Planck-SocietyState of Niedersachsen/GermanyAustralian Research CouncilInternational Science Linkages program of the Commonwealth of AustraliaCouncil of Scientific and Industrial Research of IndiaIstituto Nazionale di Fisica Nucleare of ItalySpanish Ministerio de Economia y CompetitividadConselleria d'Economia Hisenda i Innovacio of the Govern de les Illes BalearsNetherlands Organisation for Scientific ResearchPolish Ministry of Science and Higher EducationFOCUS Programme of Foundation for Polish ScienceRoyal SocietyScottish Funding CouncilScottish Universities Physics AllianceNational Aeronautics and Space AdministrationOTKA of HungaryLyon Institute of Origins (LIO)National Research Foundation of KoreaIndustry CanadaProvince of Ontario through the Ministry of Economic Development and InnovationNational Science and Engineering Research Council CanadaCarnegie TrustLeverhulme TrustDavid and Lucile Packard FoundationResearch CorporationAlfred P. Sloan FoundationAstronom
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