742 research outputs found
Atomic quantum gases in Kagom\'e lattices
We demonstrate the possibility of creating and controlling an ideal and
\textit{trimerized} optical Kagom\'e lattice, and study the low temperature
physics of various atomic gases in such lattices. In the trimerized Kagom\'e
lattice, a Bose gas exhibits a Mott transition with fractional filling factors,
whereas a spinless interacting Fermi gas at 2/3 filling behaves as a quantum
magnet on a triangular lattice. Finally, a Fermi-Fermi mixture at half filling
for both components represents a frustrated quantum antiferromagnet with a
resonating-valence-bond ground state and quantum spin liquid behavior dominated
by continuous spectrum of singlet and triplet excitations. We discuss the
method of preparing and observing such quantum spin liquid employing molecular
Bose condensates.Comment: 4 pages, 1 figure. Missing affiliations adde
High value timber composite panels from hardwood plantation thinnings.
Identifying processing strategies and products that suit young plantation hardwoods has proved challenging with low product recoveries and/or unmarketable products being the outcome of many trials. The production of rotary veneer has been demonstrated as an effective method for converting plantation hardwood trees. Across nine processing studies that included six different plantation species (Dunn’s white gum, spotted gum, Gympie messmate, spotted gum hybrid, red mahogany and western white gum), simple spindleless lathe technology was used to process 914 veneer billets totally 37.4 m3
High value timber composite panels from hardwood plantation thinnings.
Identifying processing strategies and products that suit young plantation hardwoods has proved challenging with low product recoveries and/or unmarketable products being the outcome of many trials. The production of rotary veneer has been demonstrated as an effective method for converting plantation hardwood trees. Across nine processing studies that included six different plantation species (Dunn’s white gum, spotted gum, Gympie messmate, spotted gum hybrid, red mahogany and western white gum), simple spindleless lathe technology was used to process 914 veneer billets totally 37.4 m3
Atomic Fermi gas in the trimerized Kagom\'e lattice at the filling 2/3
We study low temperature properties of an atomic spinless interacting Fermi
gas in the trimerized Kagom\'e lattice for the case of two fermions per trimer.
The system is described by a quantum spin 1/2 model on the triangular lattice
with couplings depending on bonds directions. Using exact diagonalizations we
show that the system exhibits non-standard properties of a {\it quantum
spin-liquid crystal}, combining a planar antiferromagnetic order with an
exceptionally large number of low energy excitations.Comment: 4 pages & 4 figures + 2 tables, better version of Fig.
Atomic Bose-Fermi mixtures in an optical lattice
A mixture of ultracold bosons and fermions placed in an optical lattice
constitutes a novel kind of quantum gas, and leads to phenomena, which so far
have been discussed neither in atomic physics, nor in condensed matter physics.
We discuss the phase diagram at low temperatures, and in the limit of strong
atom-atom interactions, and predict the existence of quantum phases that
involve pairing of fermions with one or more bosons, or, respectively, bosonic
holes. The resulting composite fermions may form, depending on the system
parameters, a normal Fermi liquid, a density wave, a superfluid liquid, or an
insulator with fermionic domains. We discuss the feasibility for observing such
phases in current experiments.Comment: 4 pages, 1 eps figure, misprints correcte
Quantum gases in trimerized kagom\'e lattices
We study low temperature properties of atomic gases in trimerized optical
kagom\'{e} lattices. The laser arrangements that can be used to create these
lattices are briefly described. We also present explicit results for the
coupling constants of the generalized Hubbard models that can be realized in
such lattices. In the case of a single component Bose gas the existence of a
Mott insulator phase with fractional numbers of particles per trimer is
verified in a mean field approach. The main emphasis of the paper is on an
atomic spinless interacting Fermi gas in the trimerized kagom\'{e} lattice with
two fermions per site. This system is shown to be described by a quantum spin
1/2 model on the triangular lattice with couplings that depend on the bond
directions. We investigate this model by means of exact diagonalization. Our
key finding is that the system exhibits non-standard properties of a quantum
spin-liquid crystal: it combines planar antiferromagnetic order in the ground
state with an exceptionally large number of low energy excitations. The
possibilities of experimental verification of our theoretical results are
critically discussed.Comment: 19 pages/14 figures, version to appear in Phys. Rev. A., numerous
minor corrections with respect to former lanl submissio
Mean-field theory of Bose-Fermi mixtures in optical lattices
We determine the phase diagram of a mixture of ultracold bosons and polarized
fermions placed in an optical lattice using mean field theory. In the limit of
strong atom-atom interactions, there exist quantum phases that involve pairing
of fermions with one or more bosons, or bosonic holes, respectively. We obtain
the analytic form of the phase boundaries separating these composite fermion
phases from the bosonic superfluid coexisting with Fermi liquid. We compare the
results with numerical simulations and discuss their validity and relevance for
current experiments.Comment: 4 pages, 2 eps figures, new section on experimental requirements and
some technical details adde
Trans-eQTLs Reveal That Independent Genetic Variants Associated with a Complex Phenotype Converge on Intermediate Genes, with a Major Role for the HLA
This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
Stable long-term outcomes after cochlear implantation in subjects with TMPRSS3 associated hearing loss:a retrospective multicentre study
Background: The spiral ganglion hypothesis suggests that pathogenic variants in genes preferentially expressed in the spiral ganglion nerves (SGN), may lead to poor cochlear implant (CI) performance. It was long thought that TMPRSS3 was particularly expressed in the SGNs. However, this is not in line with recent reviews evaluating CI performance in subjects with TMPRSS3-associated sensorineural hearing loss (SNHL) reporting overall beneficial outcomes. These outcomes are, however, based on variable follow-up times of, in general, 1 year or less. Therefore, we aimed to 1. evaluate long-term outcomes after CI implantation of speech recognition in quiet in subjects with TMPRSS3-associated SNHL, and 2. test the spiral ganglion hypothesis using the TMPRSS3-group. Methods: This retrospective, multicentre study evaluated long-term CI performance in a Dutch population with TMPRSS3-associated SNHL. The phoneme scores at 70 dB with CI in the TMPRSS3-group were compared to a control group of fully genotyped cochlear implant users with post-lingual SNHL without genes affecting the SGN, or severe anatomical inner ear malformations. CI-recipients with a phoneme score ≤ 70% at least 1-year post-implantation were considered poor performers and were evaluated in more detail. Results: The TMPRSS3 group consisted of 29 subjects (N = 33 ears), and the control group of 62 subjects (N = 67 ears). For the TMPRSS3-group, we found an average phoneme score of 89% after 5 years, which remained stable up to 10 years post-implantation. At both 5 and 10-year follow-up, no difference was found in speech recognition in quiet between both groups (p = 0.830 and p = 0.987, respectively). Despite these overall adequate CI outcomes, six CI recipients had a phoneme score of ≤ 70% and were considered poor performers. The latter was observed in subjects with residual hearing post-implantation or older age at implantation. Conclusion: Subjects with TMPRSS3-associated SNHL have adequate and stable long-term outcomes after cochlear implantation, equal to the performance of genotyped patient with affected genes not expressed in the SGN. These findings are not in line with the spiral ganglion hypothesis. However, more recent studies showed that TMPRSS3 is mainly expressed in the hair cells with only limited SGN expression. Therefore, we cannot confirm nor refute the spiral ganglion hypothesis.</p
Stable long-term outcomes after cochlear implantation in subjects with TMPRSS3 associated hearing loss:a retrospective multicentre study
Background: The spiral ganglion hypothesis suggests that pathogenic variants in genes preferentially expressed in the spiral ganglion nerves (SGN), may lead to poor cochlear implant (CI) performance. It was long thought that TMPRSS3 was particularly expressed in the SGNs. However, this is not in line with recent reviews evaluating CI performance in subjects with TMPRSS3-associated sensorineural hearing loss (SNHL) reporting overall beneficial outcomes. These outcomes are, however, based on variable follow-up times of, in general, 1 year or less. Therefore, we aimed to 1. evaluate long-term outcomes after CI implantation of speech recognition in quiet in subjects with TMPRSS3-associated SNHL, and 2. test the spiral ganglion hypothesis using the TMPRSS3-group. Methods: This retrospective, multicentre study evaluated long-term CI performance in a Dutch population with TMPRSS3-associated SNHL. The phoneme scores at 70 dB with CI in the TMPRSS3-group were compared to a control group of fully genotyped cochlear implant users with post-lingual SNHL without genes affecting the SGN, or severe anatomical inner ear malformations. CI-recipients with a phoneme score ≤ 70% at least 1-year post-implantation were considered poor performers and were evaluated in more detail. Results: The TMPRSS3 group consisted of 29 subjects (N = 33 ears), and the control group of 62 subjects (N = 67 ears). For the TMPRSS3-group, we found an average phoneme score of 89% after 5 years, which remained stable up to 10 years post-implantation. At both 5 and 10-year follow-up, no difference was found in speech recognition in quiet between both groups (p = 0.830 and p = 0.987, respectively). Despite these overall adequate CI outcomes, six CI recipients had a phoneme score of ≤ 70% and were considered poor performers. The latter was observed in subjects with residual hearing post-implantation or older age at implantation. Conclusion: Subjects with TMPRSS3-associated SNHL have adequate and stable long-term outcomes after cochlear implantation, equal to the performance of genotyped patient with affected genes not expressed in the SGN. These findings are not in line with the spiral ganglion hypothesis. However, more recent studies showed that TMPRSS3 is mainly expressed in the hair cells with only limited SGN expression. Therefore, we cannot confirm nor refute the spiral ganglion hypothesis.</p
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