653 research outputs found
Transience and connection in Robert Lepage's 'The Blue Dragon': China in the space of flows
Despite the stylish blend of multimedia and live performance in Robert Lepage's The Blue Dragon, touring in 2010 and 2011, critics are surprised by the reappearance of the archetypal love story in the space of contemporary intermedial performance. This article argues that the performance, set in contemporary Shanghai, explores the lived experience of transience and mobility through a narrative in which individual lives are implicated in a transnational, transcultural and transgenerational romance. Drawing on Zygmunt Bauman's work on liquid modernity and liquid love, we argue that the performance grapples with the experience of being unbound and disconnected in a liquid world
Magnetism and pairing of two-dimensional trapped fermions
The emergence of local phases in a trapped two-component Fermi gas in an
optical lattice is studied using quantum Monte Carlo simulations. We treat
temperatures that are comparable or lower than those presently achievable in
experiments and large enough systems that both magnetic and paired phases can
be detected by inspection of the behavior of suitable short-range correlations.
We use the latter to suggest the interaction strength and temperature range at
which experimental observation of incipient magnetism and d-wave pairing are
more likely and evaluate the relation between entropy and temperature in
two-dimensional confined fermionic systems.Comment: 4 pages + supplementary materia
Nondestructive testing techniques used in analysis of honeycomb structure bond strength
DOT /Driver-Displacement Oriented Transducer/, applicable to both lap shear type application and honeycomb sandwich structures, measures the displacement of the honeycomb composite face sheet. It incorporates an electromagnetic driver and a displacement measuring system into a single unit to provide noncontact bond strength measurements
Physical Activity Clinical Champions: A Peer-to-Peer Physical Activity Education Programme in England.
Physical inactivity is a key risk factor for morbidity and mortality worldwide1. Targeted interventions aim to increase activity participation, with healthcare professionals (HCPs) having a vital role in its promotion. The England-based Physical Activity Clinical Champion Programme is a global example of a professional development programme designed to harness HCPs influence. This editorial reflects its history, with insight from some key individuals who shaped it
Interaction effects and quantum phase transitions in topological insulators
We study strong correlation effects in topological insulators via the Lanczos
algorithm, which we utilize to calculate the exact many-particle ground-state
wave function and its topological properties. We analyze the simple,
noninteracting Haldane model on a honeycomb lattice with known topological
properties and demonstrate that these properties are already evident in small
clusters. Next, we consider interacting fermions by introducing repulsive
nearest-neighbor interactions. A first-order quantum phase transition was
discovered at finite interaction strength between the topological band
insulator and a topologically trivial Mott insulating phase by use of the
fidelity metric and the charge-density-wave structure factor. We construct the
phase diagram at as a function of the interaction strength and the
complex phase for the next-nearest-neighbor hoppings. Finally, we consider the
Haldane model with interacting hard-core bosons, where no evidence for a
topological phase is observed. An important general conclusion of our work is
that despite the intrinsic nonlocality of topological phases their key
topological properties manifest themselves already in small systems and
therefore can be studied numerically via exact diagonalization and observed
experimentally, e.g., with trapped ions and cold atoms in optical lattices.Comment: 13 pages, 12 figures. Published versio
Locating the source of projectile fluid droplets
The ill-posed projectile problem of finding the source height from spattered
droplets of viscous fluid is a longstanding obstacle to accident reconstruction
and crime scene analysis. It is widely known how to infer the impact angle of
droplets on a surface from the elongation of their impact profiles. However,
the lack of velocity information makes finding the height of the origin from
the impact position and angle of individual drops not possible. From aggregate
statistics of the spatter and basic equations of projectile motion, we
introduce a reciprocal correlation plot that is effective when the polar launch
angle is concentrated in a narrow range. The vertical coordinate depends on the
orientation of the spattered surface, and equals the tangent of the impact
angle for a level surface. When the horizontal plot coordinate is twice the
reciprocal of the impact distance, we can infer the source height as the slope
of the data points in the reciprocal correlation plot. If the distribution of
launch angles is not narrow, failure of the method is evident in the lack of
linear correlation. We perform a number of experimental trials, as well as
numerical calculations and show that the height estimate is insensitive to
aerodynamic drag. Besides its possible relevance for crime investigation,
reciprocal-plot analysis of spatter may find application to volcanism and other
topics and is most immediately applicable for undergraduate science and
engineering students in the context of crime-scene analysis.Comment: To appear in the American Journal of Physics (ms 23338). Improved
readability and organization in this versio
Effects of D-amino acid oxidase inhibition on memory performance and long-term potentiation in vivo
N-methyl-d-aspartate receptor (NMDAR) activation can initiate changes in synaptic strength, evident as long-term potentiation (LTP), and is a key molecular correlate of memory formation. Inhibition of d-amino acid oxidase (DAAO) may increase NMDAR activity by regulating d-serine concentrations, but which neuronal and behavioral effects are influenced by DAAO inhibition remain elusive. In anesthetized rats, extracellular field excitatory postsynaptic potentials (fEPSPs) were recorded before and after a theta frequency burst stimulation (TBS) of the Schaffer collateral pathway of the CA1 region in the hippocampus. Memory performance was assessed after training with tests of contextual fear conditioning (FC, mice) and novel object recognition (NOR, rats). Oral administration of 3, 10, and 30 mg/kg 4H-furo[3,2-b]pyrrole-5-carboxylic acid (SUN) produced dose-related and steady increases of cerebellum d-serine in rats and mice, indicative of lasting inhibition of central DAAO. SUN administered 2 h prior to training improved contextual fear conditioning in mice and novel object recognition memory in rats when tested 24 h after training. In anesthetized rats, LTP was established proportional to the number of TBS trains. d-cycloserine (DCS) was used to identify a submaximal level of LTP (5× TBS) that responded to NMDA receptor activation; SUN administered at 10 mg/kg 3–4 h prior to testing similarly increased in vivo LTP levels compared to vehicle control animals. Interestingly, in vivo administration of DCS also increased brain d-serine concentrations. These results indicate that DAAO inhibition increased NMDAR-related synaptic plasticity during phases of post training memory consolidation to improve memory performance in hippocampal-dependent behavioral tests
The Rising Incidence of Type 1 Diabetes Is Accounted for by Cases With Lower-Risk Human Leukocyte Antigen Genotypes
OBJECTIVE—The rising incidence of type 1 diabetes has been attributed to environment, implying a lesser role for genetic susceptibility. However, the rise could be accounted for by either more cases with classic high-risk genes or by cases with other risk genes. Separately, for any degree of genetic susceptibility, age at presentation may decrease in a permissive environment. To examine these possibilities, human leukocyte antigen (HLA) class II DRB1 genes known to confer risk for type 1 diabetes were analyzed in relation to year of birth and age at diagnosis over the last five decades
Long-term forest soil warming alters microbial communities in temperate forest soils
Soil microbes are major drivers of soil carbon cycling, yet we lack an understanding of how climate warming will affect microbial communities. Three ongoing field studies at the Harvard Forest Long-term Ecological Research (LTER) site (Petersham, MA) have warmed soils 5°C above ambient temperatures for 5, 8, and 20 years. We used this chronosequence to test the hypothesis that soil microbial communities have changed in response to chronic warming. Bacterial community composition was studied using Illumina sequencing of the 16S ribosomal RNA gene, and bacterial and fungal abundance were assessed using quantitative PCR. Only the 20-year warmed site exhibited significant change in bacterial community structure in the organic soil horizon, with no significant changes in the mineral soil. The dominant taxa, abundant at 0.1% or greater, represented 0.3% of the richness but nearly 50% of the observations (sequences). Individual members of the Actinobacteria, Alphaproteobacteria and Acidobacteria showed strong warming responses, with one Actinomycete decreasing from 4.5 to 1% relative abundance with warming. Ribosomal RNA copy number can obfuscate community profiles, but is also correlated with maximum growth rate or trophic strategy among bacteria. Ribosomal RNA copy number correction did not affect community profiles, but rRNA copy number was significantly decreased in warming plots compared to controls. Increased bacterial evenness, shifting beta diversity, decreased fungal abundance and increased abundance of bacteria with low rRNA operon copy number, including Alphaproteobacteria and Acidobacteria, together suggest that more or alternative niche space is being created over the course of long-term warming
- …