352 research outputs found
Quantum teleportation over the Swisscom telecommunication network
We present a quantum teleportation experiment in the quantum relay
configuration using the installed telecommunication network of Swisscom. In
this experiment, the Bell state measurement occurs well after the entanglement
has been distributed, at a point where the photon upon which data is teleported
is already far away, and the entangled qubits are photons created from a
different crystal and laser pulse than the teleported qubit. A raw fidelity of
0.93+/-0.04 has been achieved using a heralded single-photon source.Comment: 6 pages, 7 figures, updated references on May 3rd. To be published in
Journal of the Optical Society of America B, Feature issue "Optical
Quantum-Information Science", February 200
Extended Cave Drip Water Time Series Captures the 2015â2016 El Niño in Northern Borneo
Time series of cave drip water oxygen isotopes (ÎŽ18O) provide siteâspecific assessments of the contributions of climate and karst processes to stalagmite ÎŽ18O records employed for hydroclimate reconstructions. We present ~12âyearâlong time series of biweekly cave drip water ÎŽ18O variations from three sites as well as a daily resolved local rainfall ÎŽ18O record from Gunung Mulu National Park in northern Borneo. Drip water ÎŽ18O variations closely match rainfall ÎŽ18O variations averaged over the preceding 3â18 months. We observe coherent interannual drip water ÎŽ18O variability of ~3â° to 5â° related to the El NiñoâSouthern Oscillation (ENSO), with sustained positive rainfall and drip water ÎŽ18O anomalies observed during the 2015/2016 El Niño. Evidence of nonlinear behavior at one of three drip water monitoring sites implies a timeâvarying contribution from a longerâterm reservoir. Our results suggest that wellâreplicated, highâresolution stalagmite ÎŽ18O reconstructions from Mulu could characterize past ENSOârelated variability in regional hydroclimate.Plain Language SummaryCave stalagmites allow for the reconstruction of past regional rainfall variability over the last hundreds of thousands of years with robust age control. Such reconstructions rely on the fact that differences in the isotopic composition of rainwater set by regional rainfall patterns is preserved as the rainwater travels through cave bedrock to feed the cave drip waters forming stalagmites. Longâterm monitoring of rainwater and cave drip water isotopes ground truth the climate to stalagmite relationship across modernâday changes in regional rainfall. Twelve years of monitoring data presented in this study identify individual El NiñoâSouthern Oscillation events in rainfall and cave drip water isotopic composition, providing a strong foundation for stalagmiteâbased climate reconstructions from this site.Key PointsThree 12âyearâlong cave drip water ÎŽ18O time series capture El Niño and La Niña events in northern BorneoEstimates of karst residence times range from 3 to 18 months, with a secondary contribution from a longerâterm reservoir at one drip siteDrip water nonstationarity implies multiple stalagmites are required to reconstruct El NiñoâSouthern Oscillation variability over timePeer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154266/1/grl60264-sup-0002-2019GL086363-SI.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154266/2/grl60264_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154266/3/grl60264.pd
Why, what, and how? case study on law, risk, and decision making as necessary themes in built environment teaching
The paper considers (and defends) the necessity of including legal studies as a core part of built environment undergraduate and postgraduate curricula. The writer reflects upon his own experience as a lawyer working alongside and advising built environment professionals in complex land remediation and site safety management situations in the United Kingdom and explains how themes of liability, risk, and decision making can be integrated into a practical simulation in order to underpin more traditional lecture-based law teaching. Through reflection upon the writer's experiments with simulation-based teaching, the paper suggests some innovations that may better orientate law teaching to engage these themes and, thereby, enhance the relevance of law studies to the future needs of built environment professionals in practice.</p
Entangling single photons on a beamsplitter
We report on a scheme for the creation of time-bin entangled states out of
two subsequent single photons. Both photons arrive on the same input port of a
beamsplitter and the situation in which the photons leave the beamsplitter on
different output ports is post-selected. We derive a full quantum mechanical
analysis of such time-bin entanglement for emitters subject to uncorrelated
dephasing processes and apply this model to sequential single photons emerging
from a single semiconductor quantum dot. Our results indicate that the
visibility of entanglement is degraded by decoherence effects in the quantum
dot, but can be restored by use of CQED effects, namely the Purcell effect.Comment: Accepted EPJ
The promise of the affordable artist's studio: Governing creative spaces in London
The role of artists' organisations in populating and popularising postindustrial urban areas is well documented. However, what are less apparent are analyses of how spaces of artistic production are organised and governed in these areas. This paper explores, via an analysis of organisational documents and practices, the techniques used by London-based affordable studio providers to imagine, calculate, and make material low-cost workspace for artists. The argument made is that the negotiation of competing agendas around the production of cultural, economic, and social benefit by affordable studio providers has led to the emergence of a specific form of affordable studio. This analysis will thus show how configurations of creative space emerge from mundane techniques of measurement and governance. © 2013 Pion and its Licensors
Taking Be proud! Be responsible! to the Suburbs: A Replication Study
CONTEXT: An important phase of HIV prevention research is replicating successful interventions with different groups and in different settings.
METHODS: Be Proud! Be Responsible!, a successful intervention originally targeting black urban males and carried out in nonschool settings, was presented in health classes at urban and suburban schools with diverse student bodies. A group-randomized intervention study, which included 1,357 ninth and 10th graders from 10 paired schools in a Midwestern metropolitan area, was conducted in 2000-2002. Half the schools received the intervention, and half received a general health promotion program. Students\u27 reports of their sexual behavior and selected cognitive mediators were analyzed immediately following the programs and four and 12 months later.
RESULTS: Compared with students who received the control curriculum, students exposed to the intervention reported significantly greater knowledge of HIV, other STDs and condoms; greater confidence in their ability to control sexual impulses, to use condoms and to negotiate the use of condoms; and stronger intentions to use condoms. Stratified analyses revealed that the strongest intervention impacts were on knowledge and efficacy among males and students attending suburban schools. The intervention had no impact on sexual initiation, frequency of intercourse or condom use.
CONCLUSIONS: Schools are a logical and viable setting for the dissemination and acquisition of information about HIV, including prevention strategies. However, the behavioral impact of an intervention may not be easily transferable when the program is taught outside a carefully controlled, nonschool setting
Tomato: a crop species amenable to improvement by cellular and molecular methods
Tomato is a crop plant with a relatively small DNA content per haploid genome and a well developed genetics. Plant regeneration from explants and protoplasts is feasable which led to the development of efficient transformation procedures.
In view of the current data, the isolation of useful mutants at the cellular level probably will be of limited value in the genetic improvement of tomato. Protoplast fusion may lead to novel combinations of organelle and nuclear DNA (cybrids), whereas this technique also provides a means of introducing genetic information from alien species into tomato. Important developments have come from molecular approaches. Following the construction of an RFLP map, these RFLP markers can be used in tomato to tag quantitative traits bred in from related species. Both RFLP's and transposons are in the process of being used to clone desired genes for which no gene products are known. Cloned genes can be introduced and potentially improve specific properties of tomato especially those controlled by single genes. Recent results suggest that, in principle, phenotypic mutants can be created for cloned and characterized genes and will prove their value in further improving the cultivated tomato.
A putative relay circuit providing low-threshold mechanoreceptive input to lamina I projection neurons via vertical cells in lamina II of the rat dorsal horn
Background:
Lamina I projection neurons respond to painful stimuli, and some are also activated by touch or hair movement. Neuropathic pain resulting from peripheral nerve damage is often associated with tactile allodynia (touch-evoked pain), and this may result from increased responsiveness of lamina I projection neurons to non-noxious mechanical stimuli. It is thought that polysynaptic pathways involving excitatory interneurons can transmit tactile inputs to lamina I projection neurons, but that these are normally suppressed by inhibitory interneurons. Vertical cells in lamina II provide a potential route through which tactile stimuli can activate lamina I projection neurons, since their dendrites extend into the region where tactile afferents terminate, while their axons can innervate the projection cells. The aim of this study was to determine whether vertical cell dendrites were contacted by the central terminals of low-threshold mechanoreceptive primary afferents.
Results:
We initially demonstrated contacts between dendritic spines of vertical cells that had been recorded in spinal cord slices and axonal boutons containing the vesicular glutamate transporter 1 (VGLUT1), which is expressed by myelinated low-threshold mechanoreceptive afferents. To confirm that the VGLUT1 boutons included primary afferents, we then examined vertical cells recorded in rats that had received injections of cholera toxin B subunit (CTb) into the sciatic nerve. We found that over half of the VGLUT1 boutons contacting the vertical cells were CTb-immunoreactive, indicating that they were of primary afferent origin.
Conclusions:
These results show that vertical cell dendritic spines are frequently contacted by the central terminals of myelinated low-threshold mechanoreceptive afferents. Since dendritic spines are associated with excitatory synapses, it is likely that most of these contacts were synaptic. Vertical cells in lamina II are therefore a potential route through which tactile afferents can activate lamina I projection neurons, and this pathway could play a role in tactile allodynia
Searching for gravitational waves from known pulsars
We present upper limits on the amplitude of gravitational waves from 28
isolated pulsars using data from the second science run of LIGO. The results
are also expressed as a constraint on the pulsars' equatorial ellipticities. We
discuss a new way of presenting such ellipticity upper limits that takes
account of the uncertainties of the pulsar moment of inertia. We also extend
our previous method to search for known pulsars in binary systems, of which
there are about 80 in the sensitive frequency range of LIGO and GEO 600.Comment: Accepted by CQG for the proceeding of GWDAW9, 7 pages, 2 figure
Analysis of LIGO data for gravitational waves from binary neutron stars
We report on a search for gravitational waves from coalescing compact binary
systems in the Milky Way and the Magellanic Clouds. The analysis uses data
taken by two of the three LIGO interferometers during the first LIGO science
run and illustrates a method of setting upper limits on inspiral event rates
using interferometer data. The analysis pipeline is described with particular
attention to data selection and coincidence between the two interferometers. We
establish an observational upper limit of 1.7 \times 10^{2}M_\odot$.Comment: 17 pages, 9 figure
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