3,535 research outputs found
How university students are taught about sustainability, and how they want to be taught: the importance of the hidden curriculum
File replaced (incorrect version) on 09/05/2022 by KT (LDS)
Negative diffraction pattern dynamics in nonlinear cavities with left-handed materials
We study a ring cavity filled with a slab of a right-handed material and a
slab of a left-handed material. Both layers are assumed to be nonlinear Kerr
media. First, we derive a model for the propagation of light in a left-handed
material. By constructing a mean-field model, we show that the sign of
diffraction can be made either positive or negative in this resonator,
depending on the thicknesses of the layers. Subsequently, we demonstrate that
the dynamical behavior of the modulation instability is strongly affected by
the sign of the diffraction coefficient. Finally, we study the dissipative
structures in this resonator and reveal the predominance of a two-dimensional
up-switching process over the formation of spatially periodic structures,
leading to the truncation of the homogeneous hysteresis cycle.Comment: 8 pages, 5 figure
QCD equation of state in a virial expansion
We describe recent three-flavor QCD lattice data for the pressure, speed of
soun d and interaction measure at nonzero temperature and vanishing chemical
potentia l within a virial expansion. For the deconfined phase we use a
phenomenological model which includes non-pert urbative effects from dimension
two gluon condensates that reproduce the free en ergy of quenched QCD very
well. The hadronic phase is parameterized by a generalized resonance-gas model.
Furthermore, we extend this approach to finite quark densities introducing an
ex plicit -dependence of the interaction. We calculate pressure,
quark-number density, entropy and energy density and compare to results of
lattice calculatio ns. We, additionally, investigate the structure of the phase
diagram by calculating the isobaric and isentropic lines as well as the
critical endpoint in the ()-plane.Comment: 9 pages, 11 figures. Submitted to Phys. Rev.
A study of patent thickets
Report analysing whether entry of UK enterprises into patenting in a technology area is affected by patent thickets in the technology area
Identification of PKD1L1 Gene Variants in Children with the Biliary Atresia Splenic Malformation Syndrome
Biliary atresia (BA) is the most common cause of end‐stage liver disease in children and the primary indication for pediatric liver transplantation, yet underlying etiologies remain unknown. Approximately 10% of infants affected by BA exhibit various laterality defects (heterotaxy) including splenic abnormalities and complex cardiac malformations — a distinctive subgroup commonly referred to as the biliary atresia splenic malformation (BASM) syndrome. We hypothesized that genetic factors linking laterality features with the etiopathogenesis of BA in BASM patients could be identified through whole exome sequencing (WES) of an affected cohort. DNA specimens from 67 BASM subjects, including 58 patient‐parent trios, from the NIDDK‐supported Childhood Liver Disease Research Network (ChiLDReN) underwent WES. Candidate gene variants derived from a pre‐specified set of 2,016 genes associated with ciliary dysgenesis and/or dysfunction or cholestasis were prioritized according to pathogenicity, population frequency, and mode of inheritance. Five BASM subjects harbored rare and potentially deleterious bi‐allelic variants in polycystin 1‐like 1, PKD1L1, a gene associated with ciliary calcium signaling and embryonic laterality determination in fish, mice and humans. Heterozygous PKD1L1 variants were found in 3 additional subjects. Immunohistochemical analysis of liver from the one BASM subject available revealed decreased PKD1L1 expression in bile duct epithelium when compared to normal livers and livers affected by other non‐cholestatic diseases. Conclusion WES identified bi‐allelic and heterozygous PKD1L1 variants of interest in 8 BASM subjects from the ChiLDReN dataset. The dual roles for PKD1L1 in laterality determination and ciliary function suggest that PKD1L1 is a new, biologically plausible, cholangiocyte‐expressed candidate gene for the BASM syndrome
The 2022 dengue outbreak in Bangladesh: hypotheses for the late resurgence of cases and fatalities
Abstract Bangladesh reported the highest number of annual deaths (n = 281) related to dengue virus infection in 2022 since the virus reappeared in the country in 2000. Earlier studies showed that &gt;92% of the annual cases occurred between the months of August and September. The 2022 outbreak is characterized by late onset of dengue cases with unusually higher deaths in colder months, that is, October–December. Here we present possible hypotheses and explanations for this late resurgence of dengue cases. First, in 2022, the rainfall started late in the season. Compared to the monthly average rainfall for September and October between 2003 and 2021, there was 137 mm of additional monthly rainfall recorded in September and October 2022. Furthermore, the year 2022 was relatively warmer with a 0.71°C increased temperature than the mean annual temperature of the past 20 yr. Second, a new dengue virus serotype, DENV-4, had recently reintroduced/reappeared in 2022 and become the dominant serotype in the country for a large naïve population. Third, the post-pandemic return of normalcy after 2 yr of nonpharmaceutical social measures facilitates extra mosquito breeding habitats, especially in construction sites. Community engagement and regular monitoring and destruction of Aedes mosquitoes’ habitats should be prioritized to control dengue virus outbreaks in Bangladesh.</jats:p
The chiral transition and U(1)_A symmetry restoration from lattice QCD using Domain Wall Fermions
We present results on both the restoration of the spontaneously broken chiral
symmetry and the effective restoration of the anomalously broken U(1)_A
symmetry in finite temperature QCD at zero chemical potential using lattice
QCD. We employ domain wall fermions on lattices with fixed temporal extent
N_\tau = 8 and spatial extent N_\sigma = 16 in a temperature range of T = 139 -
195 MeV, corresponding to lattice spacings of a \approx 0.12 - 0.18 fm. In
these calculations, we include two degenerate light quarks and a strange quark
at fixed pion mass m_\pi = 200 MeV. The strange quark mass is set near its
physical value. We also present results from a second set of finite temperature
gauge configurations at the same volume and temporal extent with slightly
heavier pion mass. To study chiral symmetry restoration, we calculate the
chiral condensate, the disconnected chiral susceptibility, and susceptibilities
in several meson channels of different quantum numbers. To study U(1)_A
restoration, we calculate spatial correlators in the scalar and pseudo-scalar
channels, as well as the corresponding susceptibilities. Furthermore, we also
show results for the eigenvalue spectrum of the Dirac operator as a function of
temperature, which can be connected to both U(1)_A and chiral symmetry
restoration via Banks-Casher relations.Comment: 80 pages, 14 figures, 4 appendice
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