1,266 research outputs found
Implementing an electronic sideband offset lock for precision spectroscopy in radium
We demonstrate laser frequency stabilization with at least 6 GHz of offset
tunability using an in-phase/quadrature (IQ) modulator to generate electronic
sidebands (ESB) on a titanium sapphire laser at 714 nm and we apply this
technique to the precision spectroscopy of Ra, and Ra. By
locking the laser to a single resonance of a high finesse optical cavity and
adjusting the lock offset, we determine the frequency difference between the
magneto-optical trap (MOT) transitions in the two isotopes to be
MHz, a factor of 29 more precise than the previously available data. Using the
known value of the hyperfine splitting of the level, we calculate
the isotope shift for the to transition to be
MHz, which is a factor of 8 more precise than the best available
value. Our technique could be applied to countless other atomic systems to
provide unprecedented precision in isotope shift spectroscopy and other
relative frequency comparisons
Encoding a magic state with beyond break-even fidelity
We distill magic states to complete a universal set of fault-tolerant logic
gates that is needed for large-scale quantum computing. By encoding better
quality input states for our distillation procedure, we can reduce the
considerable resource cost of producing magic states. We demonstrate an
error-suppressed encoding scheme for a two-qubit input magic state, that we
call the CZ state, on an array of superconducting qubits. Using a complete set
of projective logical Pauli measurements, that are also tolerant to a single
circuit error, we propose a circuit that demonstrates a magic state prepared
with infidelity . Additionally, the yield of
our scheme increases with the use of adaptive circuit elements that are
conditioned in real time on mid-circuit measurement outcomes. We find our
results are consistent with variations of the experiment, including where we
use only post-selection in place of adaptive circuits, and where we interrogate
our output state using quantum state tomography on the data qubits of the code.
Remarkably, the error-suppressed preparation experiment demonstrates a fidelity
exceeding that of the preparation of the same unencoded magic-state on any
single pair of physical qubits on the same device.Comment: 10 pages, 7 figures, comments welcom
iPSCORE: A Resource of 222 iPSC Lines Enabling Functional Characterization of Genetic Variation across a Variety of Cell Types.
Large-scale collections of induced pluripotent stem cells (iPSCs) could serve as powerful model systems for examining how genetic variation affects biology and disease. Here we describe the iPSCORE resource: a collection of systematically derived and characterized iPSC lines from 222 ethnically diverse individuals that allows for both familial and association-based genetic studies. iPSCORE lines are pluripotent with high genomic integrity (no or low numbers of somatic copy-number variants) as determined using high-throughput RNA-sequencing and genotyping arrays, respectively. Using iPSCs from a family of individuals, we show that iPSC-derived cardiomyocytes demonstrate gene expression patterns that cluster by genetic background, and can be used to examine variants associated with physiological and disease phenotypes. The iPSCORE collection contains representative individuals for risk and non-risk alleles for 95% of SNPs associated with human phenotypes through genome-wide association studies. Our study demonstrates the utility of iPSCORE for examining how genetic variants influence molecular and physiological traits in iPSCs and derived cell lines
The HERMES Dual-Radiator Ring Imaging Cerenkov Detector
The construction and use of a dual radiator Ring Imaging Cerenkov(RICH)
detector is described. This instrument was developed for the HERMES experiment
at DESY which emphasizes measurements of semi-inclusive deep-inelastic
scattering. It provides particle identification for pions, kaons, and protons
in the momentum range from 2 to 15 GeV, which is essential to these studies.
The instrument uses two radiators, C4F10, a heavy fluorocarbon gas, and a wall
of silica aerogel tiles. The use of aerogel in a RICH detector has only
recently become possible with the development of clear, large homogeneous and
hydrophobic aerogel. A lightweight mirror was constructed using a newly
perfected technique to make resin-coated carbon-fiber surfaces of optical
quality. The photon detector consists of 1934 photomultiplier tubes for each
detector half, held in a soft steel matrix to provide shielding against the
residual field of the main spectrometer magnet.Comment: 25 pages, 23 figure
The Effects of Trauma History and Prenatal Affective Symptoms on Obstetric Outcomes: Trauma, Anxiety, and Birthweight
Prenatal maternal mood may explain the adverse obstetric outcomes seen in disadvantaged populations yet the effects of trauma history are not well studied. We examined the impact of trauma exposure and mood symptoms on obstetric outcomes in 358 women. Women with antecedent trauma were more likely to have a history of depression χ2(1, N = 358) = 19.2, p =.001; OR = 2.83, 95% CI [1.81, 4.42], were younger at their first pregnancy t(356) = −2.97, p = .003 and had a higher number of previous pregnancies t(356) = 2.77, p = .011 compared to those with no trauma exposure. Women with prenatal anxiety had significantly smaller babies than nonanxious women F(1, 322) = 5.32, p = .024. Trauma history magnified the effects of maternal prenatal mood on birth weight; the moderating effect was limited to those who first experienced a trauma under 18 years of age F(14, 320) = 2.44, p =.005. Childhood trauma exposure increases vulnerability for low birthweight delivery associated with prenatal mood disturbance. Screening pregnant women for trauma history and current mood symptoms is indicated
Fish Farms at Sea: The Ground Truth from Google Earth
In the face of global overfishing of wild-caught seafood, ocean fish farming has augmented the supply of fresh fish to western markets and become one of the fastest growing global industries. Accurate reporting of quantities of wild-caught fish has been problematic and we questioned whether similar discrepancies in data exist in statistics for farmed fish production. In the Mediterranean Sea, ocean fish farming is prevalent and stationary cages can be seen off the coasts of 16 countries using satellite imagery available through Google Earth. Using this tool, we demonstrate here that a few trained scientists now have the capacity to ground truth farmed fish production data reported by the Mediterranean countries. With Google Earth, we could examine 91% of the Mediterranean coast and count 248 tuna cages (circular cages >40 m diameter) and 20,976 other fish cages within 10 km offshore, the majority of which were off Greece (49%) and Turkey (31%). Combining satellite imagery with assumptions about cage volume, fish density, harvest rates, and seasonal capacity, we make a conservative approximation of ocean-farmed finfish production for 16 Mediterranean countries. Our overall estimate of 225,736 t of farmed finfish (not including tuna) in the Mediterranean Sea in 2006 is only slightly more than the United Nations Food and Agriculture Organization reports. The results demonstrate the reliability of recent FAO farmed fish production statistics for the Mediterranean as well as the promise of Google Earth to collect and ground truth data
Costs and difficulties of recruiting patients to provide e-health support: pilot study in one primary care trust
<p>Abstract</p> <p>Background</p> <p>Better use of e-health services by patients could improve outcomes and reduce costs but there are concerns about inequalities of access. Previous research in outpatients suggested that anonymous personal email support may help patients with long term conditions to use e-health, but recruiting earlier in their 'journey' may benefit patients more. This pilot study explored the feasibility and cost of recruiting patients for an e-health intervention in one primary care trust.</p> <p>Methods</p> <p>The sample comprised 46 practices with total patient population of 250,000. We approached all practices using various methods, seeking collaboration to recruit patients via methods agreed with each practice. A detailed research diary was kept of time spent recruiting practices and patients. Researcher time was used to estimate costs. Patients who consented to participate were offered email support for their use of the Internet for health.</p> <p>Results</p> <p>Eighteen practices agreed to take part; we recruited 27 patients, most (23/27) from five practices. Practices agreed to recruit patients for an e-health intervention via waiting room leaflets (16), posters (16), practice nurses (15), doctors giving patients leaflets (5), a study website link (7), inclusion in planned mailshots (2), and a special mailshot to patients selected from practice computers (1). After low recruitment response we also recruited directly in five practices through research assistants giving leaflets to patients in waiting rooms. Ten practices recruited no patients. Those practices that were more difficult to recruit were less likely to recruit patients. Leaving leaflets for practice staff to distribute and placing posters in the practice were not effective in recruiting patients. Leaflets handed out by practice nurses and website links were more successful. The practice with lowest costs per patient recruited (£70) used a special mailshot to selected patients.</p> <p>Conclusion</p> <p>Recruitment via general practice was not successful and was therefore expensive. Direct to consumer methods and recruitment of patients in outpatients to offer email support may be more cost effective. If recruitment in general practice is required, contacting practices by letter and email, not following up non-responding practices, and recruiting patients with selected conditions by special mailshot may be the most cost-effective approach.</p
Effectiveness of a biopsychosocial e-learning intervention on the clinical judgements of medical students and GP trainees regarding future risk of disability in patients with chronic lower back pain: study protocol for a randomised controlled trial
Introduction Chronic lower back pain (CLBP) is a major healthcare problem with wide ranging effects. It is a priority for appropriate management of CLBP to get individuals back to work as early as possible. Interventions that identify biopsychosocial barriers to recovery have been observed to lead to successfully reduced pain-related work absences and increased return to work for individuals with CLBP. Modern conceptualisations of pain adopt a biopsychosocial approach, such as the flags approach. Biopsychosocial perspectives have been applied to judgements about future adjustment, recovery from pain and risk of long-term disability; and provide a helpful model for understanding the importance of contextual interactions between psychosocial and biological variables in the experience of pain. Medical students and general practitioner (GP) trainees are important groups to target with education about biopsychosocial conceptualisations of pain and related clinical implications. Aim The current study will compare the effects of an e-learning intervention that focuses on a biopsychosocial model of pain, on the clinical judgements of medical students and trainees. Methods and analysis Medical student and GP trainee participants will be randomised to 1 of 2 study conditions: (1) a 20 min e-learning intervention focused on the fundamentals of the flags approach to clinical judgement-making regarding risk of future pain-related disability; compared with a (2) wait-list control group on judgement accuracy and weighting (ie, primary outcomes); flags approach knowledge, attitudes and beliefs towards pain, judgement speed and empathy (ie, secondary outcomes). Participants will be assessed at preintervention and postintervention. Ethics and dissemination The study will be performed in agreement with the Declaration of Helsinki and is approved by the National University of Ireland Galway Research Ethics Committee. The results of the trial will be published according to the CONSORT statement and will be presented at conferences and reported in peer-reviewed journals
The PHENIX Experiment at RHIC
The physics emphases of the PHENIX collaboration and the design and current
status of the PHENIX detector are discussed. The plan of the collaboration for
making the most effective use of the available luminosity in the first years of
RHIC operation is also presented.Comment: 5 pages, 1 figure. Further details of the PHENIX physics program
available at http://www.rhic.bnl.gov/phenix
- …