955 research outputs found
The loschmidt index
We study the nodes of the wavefunction overlap between ground states of a parameterdependent Hamiltonian. These nodes are topological, and we can use them to analyze in a unifying way both equilibrium and dynamical quantum phase transitions in multiband systems. We define the Loschmidt index as the number of nodes in this overlap and discuss the relationship between this index and the wrapping number of a closed auxiliary hypersurface. This relationship allows us to compute this index systematically, using an integral representation of the wrapping number. We comment on the relationship between the Loschmidt index and other well-established topological numbers. As an example, we classify the equilibrium and dynamical quantum phase transitions of the XY model by counting the nodes in the wavefunction overlaps
A review of the importance of the Caribbean region in Oligo-Miocene low latitude planktonic foraminiferal biostratigraphy and the implications for modern biogeochronological schemes
Planktonic foraminifera are widely used in marine biostratigraphy thanks to their small size, limited stratigraphic range and abundance in oceanic sediments. The utility of planktonic foraminifera in biostratigraphy was first fully recognised within the Caribbean region during the middle of the 20th century. The area was critical for the subsequent development of the low latitude biostratigraphic schemes and remains fundamental for modern day biogeochronologies. This study presents a historical review of the Oligo-Miocene component of these biostratigraphic schemes, including the first proposed scheme of Cushman and Stainforth (1945) and the subsequent development. The work of Hans Bolli and Walter Blow is particularly highlighted due to their heavy influence on modern day biostratigraphy, including these authors initially recognising the biostratigraphic utility of a number of bioevents still applied today. These Caribbean-centric schemes are correlated to the modern-day low latitude biogeochronology of Wade et al. (2011), with this synthesis highlighting that a number of bioevents (e.g. Top Paragloborotalia kugleri and Top Catapsydrax dissimilis) have been applied consistently since their initial recognition. This in turn allows the recognisability of these bioevents to be deduced based on how consistently applied each datum has been. In addition, the range charts of six studies focusing heavily on the Caribbean have been reassessed to determine whether there is potential to apply a given bioevent, and the original author merely did not recognise the biostratigraphic utility of the species or favoured another bioevent.
In considering this historical review, a number of amendments to Wade et al. (2011) and future priorities to planktonic foraminifera biogeochronologies are suggested. Most notably, the re-introduction of Base Globigerinatella insueta as a primary bioevent due to the historical biostratigraphic importance of this species. This event now defines early Miocene Subzone M3b (Gt. insueta/Ct. dissimilis PRZ) dividing Zone M3 into an upper Subzone M3b (Base Gt. insueta) and lower Subzone M3a (Base Globigerinatella sp.). Finally, the Miocene to Recent timescale of Wade et al. (2011) has been recalibrated following more recent updates to the magnetostratigraphy (Kochhann et al., 2016; Ogg et al., 2016; Drury et al., 2017; Beddow et al., 2018) and cyclostratigraphy (Wilkens et al., 2017). The overall effect on the planktonic foraminifera biogeochronology is minor but our results become the suggested biostratigraphic framework for the low latitudes
Long term effectiveness of the mixture of diatomaceous earth and deltamethrin on wheat
A mixture of diatomaceous earth (DE) and deltamethrin (DM) was developed to control stored-grain insect pests. The formulation contains a low quantity of DE and small amounts of insecticide deltamethrin technical powder dissolved in solvent and soap. This study was initiated in order to determine how long the mixture DE/DM will provide acceptable protection against infestation by the rice weevil, Sitophilus oryzae (L.), the lesser grain borer Rhyzopertha dominica (F.) and the red flour beetle, Tribolium castaneum (Herbst), when applied to hard red spring wheat (HRSW) and stored under normal storage conditions. Immediately after treatment, all three species were controlled at 100 milligram per kg or parts per million (ppm) of DE/DM mixture. At 100 ppm, DE/DM mixture provided 100% population reduction of all three species for up to 12 months with little or no progeny produced.Keywords: Diatomaceous earth, Deltamethrin, Mixture, Wheat, Protectio
Happiness, environmental protection and market economy
The manufacturing sector is leaving the West for Asia’s low wages and good working culture. Europe would be better off keeping these manufacturing activities, slowing down wage inflation and what is more, letting a young, cheaper workforce from the East settle down within their borders. This would aid in preserving the diverse economic structure which has been characteristic for Europe.Beside the economic growth there are two more concepts which have turned into the “holy cows” of economics during the last fifty years. One is the need to constantly improve labor productivity and the other is increasing competitiveness of nations. The high labor productivity of some countries, induces severe unemployment in the globalized world. In the other hand it is high time we understood that it is not competition, but cooperation that brings more happiness to humanity.Should we still opt for “happiness” and “sanity”, it is quite obvious that we all should, in economists’ terms, define our individual welfare functions corresponding to our own set of values, staying free from the influence of media, advertisements and fashion. The cornerstone to all this is the intelligent citizen who prefers local goods and services
OPE statistics from higher-point crossing
We present new asymptotic formulas for the distribution of OPE coefficients in conformal field theories. These formulas involve products of four or more coefficients and include light-light-heavy as well as heavy-heavy-heavy contributions. They are derived from crossing symmetry of the six and higher point functions on the plane and should be interpreted as non-Gaussianities in the statistical distribution of the OPE coefficients. We begin with a formula for arbitrary operator exchanges (not necessarily primary) valid in any dimension. This is the first asymptotic formula constraining heavy-heavy-heavy OPE coefficients in d > 2. For two-dimensional CFTs, we present refined asymptotic formulas stemming from exchanges of quasi-primaries as well as Virasoro primaries.We present new asymptotic formulas for the distribution of OPE coefficients in conformal field theories. These formulas involve products of four or more coefficients and include light-light-heavy as well as heavy-heavy-heavy contributions. They are derived from crossing symmetry of the six and higher point functions on the plane and should be interpreted as non-Gaussianities in the statistical distribution of the OPE coefficients. We begin with a formula for arbitrary operator exchanges (not necessarily primary) valid in any dimension. This is the first asymptotic formula constraining heavy-heavy-heavy OPE coefficients in . For two-dimensional CFTs, we present refined asymptotic formulas stemming from exchanges of quasi-primaries as well as Virasoro primaries
Fish schooling as a basis for vertical axis wind turbine farm design
Most wind farms consist of horizontal axis wind turbines (HAWTs) due to the
high power coefficient (mechanical power output divided by the power of the
free-stream air through the turbine cross-sectional area) of an isolated
turbine. However when in close proximity to neighbouring turbines, HAWTs suffer
from a reduced power coefficient. In contrast, previous research on vertical
axis wind turbines (VAWTs) suggests that closely-spaced VAWTs may experience
only small decreases (or even increases) in an individual turbine's power
coefficient when placed in close proximity to neighbours, thus yielding much
higher power outputs for a given area of land. A potential flow model of
inter-VAWT interactions is developed to investigate the effect of changes in
VAWT spatial arrangement on the array performance coefficient, which compares
the expected average power coefficient of turbines in an array to a
spatially-isolated turbine. A geometric arrangement based on the configuration
of shed vortices in the wake of schooling fish is shown to significantly
increase the array performance coefficient based upon an array of 16x16 wind
turbines. Results suggest increases in power output of over one order of
magnitude for a given area of land as compared to HAWTs.Comment: Submitted for publication in BioInspiration and Biomimetics. Note:
The technology described in this paper is protected under both US and
international pending patents filed by the California Institute of Technolog
Discovery of Five New Pulsars in Archival Data
Reprocessing of the Parkes Multibeam Pulsar Survey has resulted in the
discovery of five previously unknown pulsars and several as-yet-unconfirmed
candidates. PSR J0922-52 has a period of 9.68 ms and a DM of 122.4 pc cm^-3.
PSR J1147-66 has a period of 3.72 ms and a DM of 133.8 pc cm^-3. PSR J1227-6208
has a period of 34.53 ms, a DM of 362.6 pc cm^-3, is in a 6.7 day binary orbit,
and was independently detected in an ongoing high-resolution Parkes survey by
Thornton et al. and also in independent processing by Einstein@Home volunteers.
PSR J1546-59 has a period of 7.80 ms and a DM of 168.3 pc cm^-3. PSR J1725-3853
is an isolated 4.79-ms pulsar with a DM of 158.2 pc cm^-3. These pulsars were
likely missed in earlier processing efforts due to their high DMs and short
periods and the large number of candidates that needed to be looked through.
These discoveries suggest that further pulsars are awaiting discovery in the
multibeam survey data.Comment: 12 pages, 2 figures, 2 tables, accepted to Ap
TFLink: an integrated gateway to access transcription factor-target gene interactions for multiple species
Analysis of transcriptional regulatory interactions and their comparisons across multiple species are crucial for progress in various fields in biology, from functional genomics to the evolution of signal transduction pathways. However, despite the rapidly growing body of data on regulatory interactions in several eukaryotes, no databases exist to provide curated high-quality information on transcription factor-target gene interactions for multiple species. Here, we address this gap by introducing the TFLink gateway, which uniquely provides experimentally explored and highly accurate information on transcription factor-target gene interactions (∼12 million), nucleotide sequences and genomic locations of transcription factor binding sites (∼9 million) for human and six model organisms: mouse, rat, zebrafish, fruit fly, worm and yeast by integrating 10 resources. TFLink provides user-friendly access to data on transcription factor-target gene interactions, interactive network visualizations and transcription factor binding sites, with cross-links to several other databases. Besides containing accurate information on transcription factors, with a clear labelling of the type/volume of the experiments (small-scale or high-throughput), the source database and the original publications, TFLink also provides a wealth of standardized regulatory data available for download in multiple formats. The database offers easy access to high-quality data for wet-lab researchers, supplies data for gene set enrichment analyses and facilitates systems biology and comparative gene regulation studies. Database URL https://tflink.net/
Black Hole to Photosphere:3D GRMHD Simulations of Collapsars Reveal Wobbling and Hybrid Composition Jets
Observational signatures of disk and jet misalignment in images of accreting black holes
Black hole accretion is one of nature's most efficient energy extraction processes. When gas falls in, a significant fraction of its gravitational binding energy is either converted into radiation or flows outwards in the form of black hole-driven jets and disk-driven winds. Recently, the Event Horizon Telescope (EHT), an Earth-size sub-millimetre radio interferometer, captured the first images of M87's black hole. These images were analysed and interpreted using general-relativistic magnetohydrodynamics (GRMHD) models of accretion disks with rotation axes aligned with the black hole spin axis. However, since infalling gas is often insensitive to the black hole spin direction, misalignment between accretion disk and black hole spin may be a common occurrence in nature. In this work, we use the general-relativistic radiative transfer (GRRT) code \texttt{BHOSS} to calculate the first synthetic radio images of (highly) tilted disk/jet models generated by our GPU-accelerated GRMHD code \texttt{HAMR}. While the tilt does not have a noticeable effect on the system dynamics beyond a few tens of gravitational radii from the black hole, the warping of the disk and jet can imprint observable signatures in EHT images on smaller scales. Comparing the images from our GRMHD models to the 43 GHz and 230 GHz EHT images of M87, we find that M87 may feature a tilted disk/jet system. Further, tilted disks and jets display significant time variability in the 230 GHz flux that can be further tested by longer-duration EHT observations of M87
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