16,966 research outputs found
Free Quarks and Antiquarks versus Hadronic Matter
Meson-meson reactions A(q_1 \bar{q}_1) + B(q_2 \bar{q}_2) to q_1 + \bar{q}_1
+ q_2 + \bar{q}_2 in high-temperature hadronic matter are found to produce an
appreciable amount of quarks and antiquarks freely moving in hadronic matter
and to establish a new mechanism for deconfinement of quarks and antiquarks in
hadronic matter.Comment: 9 pages, 3 figure
Non-degenerate solutions of universal Whitham hierarchy
The notion of non-degenerate solutions for the dispersionless Toda hierarchy
is generalized to the universal Whitham hierarchy of genus zero with
marked points. These solutions are characterized by a Riemann-Hilbert problem
(generalized string equations) with respect to two-dimensional canonical
transformations, and may be thought of as a kind of general solutions of the
hierarchy. The Riemann-Hilbert problem contains arbitrary functions
, , which play the role of generating functions of
two-dimensional canonical transformations. The solution of the Riemann-Hilbert
problem is described by period maps on the space of -tuples
of conformal maps from disks of the
Riemann sphere and their complements to the Riemann sphere. The period maps are
defined by an infinite number of contour integrals that generalize the notion
of harmonic moments. The -function (free energy) of these solutions is also
shown to have a contour integral representation.Comment: latex2e, using amsmath, amssym and amsthm packages, 32 pages, no
figur
Chemo-enzymatic saccharification strategy of microalgae chlorella sorokiniana
Biofuel production using microalgae attracted much attention because it can be cultured using CO2 and sunlight. With high carbohydrate content, microalgae have the potential to be used as a fermentation feedstock for bioethanol production. In present work, chemo-enzymatic saccharification of Chlorella sorokiniana microalgae were investigated. Chemical hydrolysis of the biomass followed by enzymatic hydrolysis and was also evaluated the effect of combining the two enzymes and the sequential addition. The effect of α-amylase concentrations was analyzed in ranged between 50 and 8000 U/g of biomass and for amyloglucosidase between 90 and 600 U/g of biomass. The higher concentrations showed the highest conversion of reducing sugars. The α-amylase concentration 8000 U/g of biomass presented a conversion of 43.06 ± 2.92% (w/w), while amyloglucosidase with 600 U/g of biomass obtained 76.57 ± 6.42% (w/w). The combination of two enzymes simultaneously was more efficient than the sequential addition for low enzyme concentrations (α-amylase 50 U/g and amyloglucosidase 90 U/g) with a total reducing sugar of 22.78 ± 3.06 and 16.92 ± 2.06% (w/w), respectively. On the other hand, using the higher enzymes concentrations, no difference was observed between the two addition strategies, 58.9 ± 3.55 and 57.05 ± 2.33% (w/w) for the sequential and simultaneous, respectively. Both strategies didn’t present advantage, since the amyloglucosidase enzyme alone produced slightly higher results. Even thought, the obtained results showed successfully performed saccharification of microalgal biomass and clearly point to microalgae use for saccharification and subsequent bioethanol production.Part of this work has been supported by European governments (INTERREG VA-POCTEP- 2014-2020; 0055_ALGARED_PLUS_5_E) and the Portuguese Science Foundation (FCT) through the grant UID/MAR/00350/2013 to the CIMA of the University of Algarve.info:eu-repo/semantics/publishedVersio
Dichotomy in the Dynamical Status of Massive Cores in Orion
To study the evolution of high mass cores, we have searched for evidence of
collapse motions in a large sample of starless cores in the Orion molecular
cloud. We used the Caltech Submillimeter Observatory telescope to obtain
spectra of the optically thin (\H13CO+) and optically thick (\HCO+) high
density tracer molecules in 27 cores with masses 1 \Ms. The red- and
blue-asymmetries seen in the line profiles of the optically thick line with
respect to the optically thin line indicate that 2/3 of these cores are not
static. We detect evidence for infall (inward motions) in 9 cores and outward
motions for 10 cores, suggesting a dichotomy in the kinematic state of the
non-static cores in this sample. Our results provide an important observational
constraint on the fraction of collapsing (inward motions) versus non-collapsing
(re-expanding) cores for comparison with model simulations.Comment: 9 pages, 2 Figures. To appear in ApJ(Letters
The Intrinsic Alignment of Dark Halo Substructures
We investigate the intrinsic alignments of dark halo substructures with their
host halo major-axis orientations both analytically and numerically.
Analytically, we derive the probability density distribution of the angles
between the minor axes of the substructures and the major axes of their host
halos from the physical principles, under the assumption that the substructure
alignment on galaxy scale is a consequence of the tidal fields of the host halo
gravitational potential. Numerically, we use a sample of four cluster-scale
halos and their galaxy-scale substructures from recent high-resolution N-body
simulations to measure the probability density distribution. We compare the
numerical distribution with the analytic prediction, and find that the two
results agree with each other very well. We conclude that our analytic model
provides a quantitative physical explanation for the intrinsic alignment of
dark halo substructures. We also discuss the possibility of discriminating our
model from the anisotropic infall scenario by testing it against very large
N-body simulations in the future.Comment: accepted version, ApJL in press, minor revision, 12 pages, 2 figure
Fabrication and Characterization of Topological Insulator BiSe Nanocrystals
In the recently discovered class of materials known as topological
insulators, the presence of strong spin-orbit coupling causes certain
topological invariants in the bulk to differ from their values in vacuum. The
sudden change of invariants at the interface results in metallic, time reversal
invariant surface states whose properties are useful for applications in
spintronics and quantum computation. However, a key challenge is to fabricate
these materials on the nanoscale appropriate for devices and probing the
surface. To this end we have produced 2 nm thick nanocrystals of the
topological insulator BiSe via mechanical exfoliation. For crystals
thinner than 10 nm we observe the emergence of an additional mode in the Raman
spectrum. The emergent mode intensity together with the other results presented
here provide a recipe for production and thickness characterization of
BiSe nanocrystals.Comment: 4 pages, 3 figures (accepted for publication in Applied Physics
Letters
Three dimensional collective charge excitations in electron-doped cuprate superconductors
High temperature cuprate superconductors consist of stacked CuO2 planes, with
primarily two dimensional electronic band structures and magnetic excitations,
while superconducting coherence is three dimensional. This dichotomy highlights
the importance of out-of-plane charge dynamics, believed to be incoherent in
the normal state, yet lacking a comprehensive characterization in
energy-momentum space. Here, we use resonant inelastic x-ray scattering (RIXS)
with polarization analysis to uncover the pure charge character of a recently
discovered collective mode in electron-doped cuprates. This mode disperses
along both the in- and, importantly, out-of-plane directions, revealing its
three dimensional nature. The periodicity of the out-of-plane dispersion
corresponds to the CuO2 plane distance rather than the crystallographic c-axis
lattice constant, suggesting that the interplane Coulomb interaction drives the
coherent out-of-plane charge dynamics. The observed properties are hallmarks of
the long-sought acoustic plasmon, predicted for layered systems and argued to
play a substantial role in mediating high temperature superconductivity.Comment: This is the version of first submission. The revised manuscript
according to peer reviews is now accepted by Nature and will be published
online on 31st Oct., 201
Quantifying the distribution of probes between subcellular locations using unsupervised pattern unmixing
Motivation: Proteins exhibit complex subcellular distributions, which may include localizing in more than one organelle and varying in location depending on the cell physiology. Estimating the amount of protein distributed in each subcellular location is essential for quantitative understanding and modeling of protein dynamics and how they affect cell behaviors. We have previously described automated methods using fluorescent microscope images to determine the fractions of protein fluorescence in various subcellular locations when the basic locations in which a protein can be present are known. As this set of basic locations may be unknown (especially for studies on a proteome-wide scale), we here describe unsupervised methods to identify the fundamental patterns from images of mixed patterns and estimate the fractional composition of them
- …