2,328 research outputs found
Saccharomyces arboricola and Its Hybrids’ Propensity for Sake Production: Interspecific Hybrids Reveal Increased Fermentation Abilities and a Mosaic Metabolic Profile
The use of interspecific hybrids during the industrial fermentation process has been well established, positioning the frontier of advancement in brewing to capitalize on the potential of Saccharomyces hybridization. Interspecific yeast hybrids used in modern monoculture inoculations benefit from a wide range of volatile metabolites that broaden the organoleptic complexity. This is the first report of sake brewing by Saccharomyces arboricola and its hybrids. S. arboricola x S. cerevisiae direct-mating generated cryotolerant interspecific hybrids which increased yields of ethanol and ethyl hexanoate compared to parental strains, important flavor attributes of fine Japanese ginjo sake rice wine. Hierarchical clustering heatmapping with principal component analysis for metabolic profiling was used in finding low levels of endogenous amino/organic acids clustered S. arboricola apart from the S. cerevisiae industrial strains. In sake fermentations, hybrid strains showed a mosaic profile of parental strains, while metabolic analysis suggested S. arboricola had a lower amino acid net uptake than S. cerevisiae. Additionally, this research found an increase in ethanolic fermentation from pyruvate and increased sulfur metabolism. Together, these results suggest S. arboricola is poised for in-depth metabolomic exploration in sake fermentation
Broadband Spectral Investigations of SGR J1550-5418 Bursts
We present the results of our broadband spectral analysis of 42 SGR
J1550-5418 bursts simultaneously detected with the Swift/X-ray Telescope (XRT)
and the Fermi/Gamma-ray Burst Monitor (GBM), during the 2009 January active
episode of the source. The unique spectral and temporal capabilities of the XRT
Windowed Timing mode have allowed us to extend the GBM spectral coverage for
these events down to the X-ray domain (0.5-10 keV). Our earlier analysis of the
GBM data found that the SGR J1550-5418 burst spectra were described equally
well with a Comptonized model or with two blackbody functions; the two models
were statistically indistinguishable. Our new broadband (0.5 - 200 keV)
spectral fits show that, on average, the burst spectra are better described
with two blackbody functions than with the Comptonized model. Thus, our joint
XRT/GBM analysis clearly shows for the first time that the SGR J1550-5418 burst
spectra might naturally be expected to exhibit a more truly thermalized
character, such as a two-blackbody or even a multi-blackbody signal. Using the
Swift and RXTE timing ephemeris for SGR J1550-5418 we construct the
distribution of the XRT burst counts with spin phase and find that it is not
correlated with the persistent X-ray emission pulse phase from SGR J1550-5418.
These results indicate that the burst emitting sites on the neutron star need
not be co-located with hot spots emitting the bulk of the persistent X-ray
emission. Finally, we show that there is a significant pulse phase dependence
of the XRT burst counts, likely demonstrating that the surface magnetic field
of SGR J1550-5418 is not uniform over the emission zone, since it is
anticipated that regions with stronger surface magnetic field could trigger
bursts more efficiently.Comment: accepted for publication in The Astrophysical Journa
Knots in a Spinor Bose-Einstein Condensate
We show that knots of spin textures can be created in the polar phase of a
spin-1 Bose-Einstein condensate, and discuss experimental schemes for their
generation and probe, together with their lifetime.Comment: 4 pages, 3 figure
Quantum tunneling of a complex systems: effects of finite size and intrinsic structure
A simple model is considered to study the effects of finite size and internal
structure in the tunneling of bound two-body systems through a potential
barrier. It is demonstrated that these effects are able to increase the
tunneling probability. Applications may include nuclear fusion,hydrogen atom
and Cooper pair tunneling.Comment: 9 page
Particle Monte Carlo simulation of string-like colloidal assembly in 2 dimensions
We simulate structural phase behavior of polymer-grafted colloidal particles
by molecular Monte Carlo technique. Interparticle potential, which has a finite
repulsive square-step outside a rigid core of the colloid, was previously
confirmed via numerical self-consistent field calculation. This model potential
is purely repulsive. We simulate these model colloids in the canonical ensemble
in 2 dimensions and find that these particles containing no interparticle
attraction self-assemble and align in a string-like assembly, at low
temperature and high density. This string-like colloidal assembly is related to
percolation phenomena. Analyzing the cluster size distribution and the average
string length, we build phase diagrams and discover that the average string
length diverges around the region where the melting transition line and the
percolation transition line cross. This result is similar to Ising spin
systems, in which the percolation transition line and the order-disorder line
meet at a critical point.Comment: 11 pages, 14 figure
Interaction network rewiring and species’ contributions to community-scale flexibility
「やわらかい」ネットワークを作るコア生物種 --生態系の柔軟性を支える種を探索する--. 京都大学プレスリリース. 2024-03-07.The architecture of species interaction networks is a key factor determining the stability of ecological communities. However, the fact that ecological network architecture can change through time is often overlooked in discussions on community-level processes, despite its theoretical importance. By compiling a time-series community dataset involving 50 spider species and 974 Hexapoda prey species/strains, we quantified the extent to which the architecture of predator–prey interaction networks could shift across time points. We then developed a framework for finding species that could increase the flexibility of the interaction network architecture. Those “network coordinator” species are expected to promote the persistence of species-rich ecological communities by buffering perturbations in communities. Although spiders are often considered as generalist predators, their contributions to network flexibility vary greatly among species. We also found that detritivorous prey species can be cores of interaction rewiring, dynamically interlinking below-ground and above-ground community dynamics. We further found that the predator–prey interactions between those network coordinators differed from those highlighted in the standard network-analytical framework assuming static topology. Analyses of network coordinators will add a new dimension to our understanding of species coexistence mechanisms and provide platforms for systematically prioritizing species in terms of their potential contributions in ecosystem conservation and restoration
Topological classification of vortex-core structures of spin-1 Bose-Einstein condensates
We classify vortex-core structures according to the topology of the order
parameter space. By developing a method to characterize how the order parameter
changes inside the vortex core. We apply this method to the spin-1
Bose-Einstein condensates and show that the vortex-core structures are
classified by winding numbers that are locally defined in the core region. We
also show that a vortex-core structure with a nontrivial winding number can be
stabilized under a negative quadratic Zeeman effect.Comment: 16 pages, 6 figure
Self-Ordering Point Clouds
In this paper we address the task of finding representative subsets of points
in a 3D point cloud by means of a point-wise ordering. Only a few works have
tried to address this challenging vision problem, all with the help of hard to
obtain point and cloud labels. Different from these works, we introduce the
task of point-wise ordering in 3D point clouds through self-supervision, which
we call self-ordering. We further contribute the first end-to-end trainable
network that learns a point-wise ordering in a self-supervised fashion. It
utilizes a novel differentiable point scoring-sorting strategy and it
constructs an hierarchical contrastive scheme to obtain self-supervision
signals. We extensively ablate the method and show its scalability and superior
performance even compared to supervised ordering methods on multiple datasets
and tasks including zero-shot ordering of point clouds from unseen categories
Positions of Point-Nodes in Borocarbide Superconductor YNi2B2C
To determine the superconducting gap function of YNi2B2C, we calculate the
local density of states (LDOS) around a single vortex core with the use of
Eilenberger theory and the band structure calculated by local density
approximation assuming various gap structures with point-nodes at different
positions. We also calculate the angular-dependent heat capacity in the vortex
state on the basis of the Doppler-Shift method. Comparing our results with the
STM/STS experiment, the angular-dependent heat capacity and thermal
conductivity, we propose the gap-structure of YNi2B2C, which has the
point-nodes and gap minima along . Our gap-structure is consistent with
all results of angular-resolved experiments.Comment: 7 pages, 5 figure
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