1,652 research outputs found
Detecting a topologically ordered phase from unbiased infinite projected entangled-pair state simulations
We present an approach to identify topological order based on unbiased
infinite projected entangled-pair states (iPEPS) simulations, i.e. where we do
not impose a virtual symmetry on the tensors during the optimization of the
tensor network ansatz. As an example we consider the ground state of the toric
code model in a magnetic field exhibiting topological order. The
optimization is done by an efficient energy minimization approach based on a
summation of tensor environments to compute the gradient. We show that the
optimized tensors, when brought into the right gauge, are approximately
symmetric, and they can be fully symmetrized a posteriori to generate a stable
topologically ordered state, yielding the correct topological entanglement
entropy and modular S and U matrices. To compute the latter we develop a
variant of the corner-transfer matrix method which is computationally more
efficient than previous approaches based on the tensor renormalization group.Comment: 16 pages, 14 figure
Lies that feel honest: Dissociating between incentive and deviance processing when evaluating dishonesty
Delayed presentations of crush injury and the controversies surrounding the missed compartment or wipe out syndrome
Detection of child abuse by Dutch preventive child-healthcare doctors and nurses:Has it changed?
Abstract
Objective
Child maltreatment (i.e., abuse and neglect) is a major cause of child morbidity and death. It is a principal topic in community child-healthcare services yet little is known about the actual detection of suspected cases. We examined trends in this detection, as well as the characteristics of parents and children associated with higher rates of detection.
Methods
We obtained data on suspected cases of physical maltreatment, as well as of emotional and sexual abuse, from Dutch national samples for children aged 3 Âľ , 5-6 and 8-12 years, for 1997/98 and 2002/03 (response rates 92% and 84%, respectively, about 4,000 children each), as registered by preventive child-healthcare doctors and nurses. We assessed changes in the detection of suspected cases and also assessed the association of suspicion with the background characteristics of parents and children.
Results
Rates increased slightly over this 5-years period, from .23% to .41%, due to a quadrupling of suspected emotional abuse cases (from .06% to .24%), but without statistical significance. Suspicion of maltreatment was found to be more likely among boys, older children, and children with low-educated fathers and mothers who were younger than 27 years at the child’s birth.
Conclusions
Professionals in Dutch preventive child-healthcare services detected fewer cases of child maltreatment than might be expected on the basis of prevalence rates of self-reported maltreatment. Detection of other types of child maltreatment thus still needs further improvement in order to reach the goal of better child health.
Longitudinal links between childhood peer acceptance and the neural correlates of sharing
Childhood peer acceptance is associated with high levels of prosocial behavior and advanced perspective taking skills. Yet, the neurobiological mechanisms underlying these associations have not been studied. This functional magnetic resonance imaging study examined the neural correlates of sharing decisions in a group of adolescents who had a stable accepted status (n = 27) and a group who had a chronic rejected status (n = 19) across six elementary school grades. Both groups of adolescents played three allocation games in which they could share money with strangers with varying costs and profits to them and the other person. Stably accepted adolescents were more likely to share their money with unknown others than chronically rejected adolescents when sharing was not costly. Neuroimaging analyses showed that stably accepted adolescents, compared to chronically rejected adolescents, exhibited higher levels of activation in the temporo-parietal junction, posterior superior temporal sulcus, temporal pole, pre-supplementary motor area, and anterior insula during costly sharing decisions. These findings demonstrate that stable peer acceptance across childhood is associated with heightened activity in brain regions previously linked to perspective taking and the detection of social norm violations during adolescence, and thereby provide insight into processes underlying the widely established links between peer acceptance and prosocial behavior
Competition between intermediate plaquette phases in SrCu(BO) under pressure
Building on the growing evidence based on NMR, magnetization, neutron
scattering, ESR, and specific heat that, under pressure, SrCu(BO)
has an intermediate phase between the dimer and the N\'eel phase, we study the
competition between two candidate phases in the context of a minimal model that
includes two types of intra- and inter-dimer interactions without enlarging the
unit cell. We show that the empty plaquette phase of the Shastry-Sutherland
model is quickly replaced by a quasi-1D full plaquette phase when intra- and/or
inter-dimer couplings take different values, and that this full plaquette phase
is in much better agreement with available experimental data than the empty
plaquette one.Comment: 19 page
Assessing the Need for a Statewide Farmers’ Market Association in Maryland
Research is funded by a grant from the USDA Federal- State Marketing Improvement Program (FSMIP). FSMIP provides matching funds to State Departments of Agriculture, State agricultural experiment stations, and other appropriate State agencies to assist in exploring new market opportunities for U.S. food and agricultural products, and to encourage research and innovation aimed at improving the efficiency and performance of the marketing system
The Oldest Stars of the Extremely Metal-Poor Local Group Dwarf Irregular Galaxy Leo A
We present deep Hubble Space Telescope single-star photometry of Leo A in B,
V, and I. Our new field of view is offset from the centrally located field
observed by Tolstoy et al. (1998) in order to expose the halo population of
this galaxy. We report the detection of metal-poor red horizontal branch stars,
which demonstrate that Leo A is not a young galaxy. In fact, Leo A is as least
as old as metal-poor Galactic Globular Clusters which exhibit red horizontal
branches, and are considered to have a minimum age of about 9 Gyr. We discuss
the distance to Leo A, and perform an extensive comparison of the data with
stellar isochrones. For a distance modulus of 24.5, the data are better than
50% complete down to absolute magnitudes of 2 or more. We can easily identify
stars with metallicities between 0.0001 and 0.0004, and ages between about 5
and 10 Gyr, in their post-main-sequence phases, but lack the detection of
main-sequence turnoffs which would provide unambiguous proof of ancient (>10
Gyr) stellar generations. Blue horizontal branch stars are above the detection
limits, but difficult to distinguish from young stars with similar colors and
magnitudes. Synthetic color-magnitude diagrams show it is possible to populate
the blue horizontal branch in the halo of Leo A. The models also suggest ~50%
of the total astrated mass in our pointing to be attributed to an ancient (>10
Gyr) stellar population. We conclude that Leo A started to form stars at least
about 9 Gyr ago. Leo A exhibits an extremely low oxygen abundance, of only 3%
of Solar, in its ionized interstellar medium. The existence of old stars in
this very oxygen-deficient galaxy illustrates that a low oxygen abundance does
not preclude a history of early star formation.Comment: 44 pages, 18 figures, accepted for publication in the August 2002
issue of AJ. High resolution figures is available at
http://www.astro.spbu.ru/staff/dio/preprints.htm
Osteomyelitis of the ribs in children: a rare and potentially challenging diagnosis
Background
Rib osteomyelitis is rare in children and can mimic other pathologies. Imaging has a major role in the diagnosing rib osteomyelitis.
Objective
To evaluate clinical presentation and imaging findings in children with rib osteomyelitis.
Materials and methods
We performed a retrospective (2009–2018) study on children with rib osteomyelitis verified by either positive culture or pathology. We excluded children with multifocal osteomyelitis or empyema necessitans. We reviewed medical charts for clinical, laboratory and pathology data, and treatment. All imaging modalities for rib abnormalities were evaluated for presence and location of osteomyelitis and abscess. We calculated descriptive statistics to compare patient demographics, clinical presentation and imaging findings.
Results
The study group included 10 children (6 boys, 4 girls), with an average age of 7.3 years (range, 3 months to 15.9 years). The most common clinical presentations were fever (n=8) and pain (n=5). Eight children had elevated inflammatory indices (leukocytosis, erythrocyte sedimentation rate [ESR], C-reactive protein [CRP]). Localized chest wall swelling was found initially in six children and later in two more children. Rib osteomyelitis was suspected on presentation in only two children. All children had chest radiographs. Rib lytic changes were found on only one chest radiograph, in two of the four ultrasound studies, and in four of eight CTs. Bone marrow signal abnormalities were seen in all eight MRIs. In nine children the osteomyelitis involved the costochondral junction. Six children had an associated abscess. Staphylococcus aureus was cultured in eight children. Osteomyelitis was diagnosed based on pathology in one child with negative cultures.
Conclusion
While rib osteomyelitis is rare, imaging findings of lytic changes at the costochondral junction combined with a history of fever, elevated inflammatory markers or localized soft-tissue swelling in the chest should raise suspicion for this disease
- …