Solving Quantum Ground-State Problems with Nuclear Magnetic Resonance

Quantum ground-state problems are computationally hard problems; for general many-body Hamiltonians, there is no classical or quantum algorithm known to be able to solve them efficiently. Nevertheless, if a trial wavefunction approximating the ground state is available, as often happens for many problems in physics and chemistry, a quantum computer could employ this trial wavefunction to project the ground state by means of the phase estimation algorithm (PEA). We performed an experimental realization of this idea by implementing a variational-wavefunction approach to solve the ground-state problem of the Heisenberg spin model with an NMR quantum simulator. Our iterative phase estimation procedure yields a high accuracy for the eigenenergies (to the 10^-5 decimal digit). The ground-state fidelity was distilled to be more than 80%, and the singlet-to-triplet switching near the critical field is reliably captured. This result shows that quantum simulators can better leverage classical trial wavefunctions than classical computers.Comment: 11 pages, 13 figure

Digital Quantum Simulation of the Statistical Mechanics of a Frustrated Magnet

Many interesting problems in physics, chemistry, and computer science are equivalent to problems of interacting spins. However, most of these problems require computational resources that are out of reach by classical computers. A promising solution to overcome this challenge is to exploit the laws of quantum mechanics to perform simulation. Several "analog" quantum simulations of interacting spin systems have been realized experimentally. However, relying on adiabatic techniques, these simulations are limited to preparing ground states only. Here we report the first experimental results on a "digital" quantum simulation on thermal states; we simulated a three-spin frustrated magnet, a building block of spin ice, with an NMR quantum information processor, and we are able to explore the phase diagram of the system at any simulated temperature and external field. These results serve as a guide for identifying the challenges for performing quantum simulation on physical systems at finite temperatures, and pave the way towards large scale experimental simulations of open quantum systems in condensed matter physics and chemistry.Comment: 7 pages for the main text plus 6 pages for the supplementary material

Regional differences in psychiatric disorders in Chile

BACKGROUND: Psychiatric epidemiological surveys in developing countries are rare and are frequently conducted in regions that are not necessarily representative of the entire country. In addition, in large countries with dispersed populations national rates may have low value for estimating the need for mental health services and programs. METHODS: The Chile Psychiatric Prevalence Study using the Composite International Diagnostic Interview was conducted in four distinct regions of the country on a stratified random sample of 2,978 people. Lifetime and 12-month prevalence and service utilization rates were estimated. RESULTS: Significant differences in the rates of major depressive disorder, substance abuse disorders, non-affective psychosis, and service utilization were found across the regions. The differential prevalence rates could not be accounted by socio-demographic differences between sites. CONCLUSIONS: Regional differences across countries may exist that have both implications for prevalence rates and service utilization. Planning mental health services for population centers that span wide geographical areas based on studies conducted in a single region may be misleading, and may result in areas with high need being underserved

Students’ perceptions of patient safety during the transition from undergraduate to postgraduate training: an activity theory analysis

Evidence that medical error can cause harm to patients has raised the attention of the health care community towards patient safety and influenced how and what medical students learn about it. Patient safety is best taught when students are participating in clinical practice where they actually encounter patients at risk. This type of learning is referred to as workplace learning, a complex system in which various factors influence what is being learned and how. A theory that can highlight potential difficulties in this complex learning system about patient safety is activity theory. Thirty-four final year undergraduate medical students participated in four focus groups about their experiences concerning patient safety. Using activity theory as analytical framework, we performed constant comparative thematic analysis of the focus group transcripts to identify important themes. We found eight general themes relating to two activities: learning to be a doctor and delivering safe patient care. Simultaneous occurrence of these two activities can cause contradictions. Our results illustrate the complexity of learning about patient safety at the workplace. Students encounter contradictions when learning about patient safety, especially during a transitional phase of their training. These contradictions create potential learning opportunities which should be used in education about patient safety. Insight into the complexities of patient safety is essential to improve education in this important area of medicine

Native human autoantibodies targeting GIPC1 identify differential expression in malignant tumors of the breast and ovary

<p>Abstract</p> <p>Background</p> <p>We have been studying the native humoral immune response to cancer and have isolated a library of fully human autoantibodies to a variety of malignancies. We previously described the isolation and characterization of two fully human monoclonal antibodies, 27.F7 and 27.B1, from breast cancer patients that target the protein known as GIPC1, an accessory PDZ-domain binding protein involved in regulation of G-protein signaling. Human monoclonal antibodies, 27.F7 and 27.B1, to GIPC1 demonstrate specific binding to malignant breast cancer tissue with no reactivity with normal breast tissue.</p> <p>Methods</p> <p>The current study employs cELISA, flow cytometry, Western blot analysis as well as immunocytochemistry, and immunohistochemistry. Data is analyzed statistically with the Fisher one-tail and two-tail tests for two independent samples.</p> <p>Results</p> <p>By screening several other cancer cell lines with 27.F7 and 27.B1 we found consistently strong staining of other human cancer cell lines including SKOV-3 (an ovarian cancer cell line). To further clarify the association of GIPC1 with breast and ovarian cancer we carefully studied 27.F7 and 27.B1 using immunocytochemical and immunohistochemical techniques. An immunohistochemical study of normal ovarian tissue, benign, borderline and malignant ovarian serous tumors, and different types of breast cancer revealed high expression of GIPC1 protein in neoplastic cells. Interestingly, antibodies 27.F7 and 27.B1 demonstrate differential staining of borderline ovarian tumors. Examination of different types of breast cancer demonstrates that the level of GIPC1 expression depends on tumor invasiveness and displays a higher expression than in benign tumors.</p> <p>Conclusion</p> <p>The present pilot study demonstrates that the GIPC1 protein is overexpressed in ovarian and breast cancer, which may provide an important diagnostic and prognostic marker and will constitute the basis for further study of the role that this protein plays in malignant diseases. In addition, this study suggests that human monoclonal antibodies 27.F7 and 27.B1 should be further evaluated as potential diagnostic tools.</p

Effects on incident reporting after educating residents in patient safety: a controlled study

<p>Abstract</p> <p>Background</p> <p>Medical residents are key figures in delivering health care and an important target group for patient safety education. Reporting incidents is an important patient safety domain, as awareness of vulnerabilities could be a starting point for improvements. This study examined effects of patient safety education for residents on knowledge, skills, attitudes, intentions and behavior concerning incident reporting.</p> <p>Methods</p> <p>A controlled study with follow-up measurements was conducted. In 2007 and 2008 two patient safety courses for residents were organized. Residents from a comparable hospital acted as external controls. Data were collected in three ways: 1] questionnaires distributed before, immediately after and three months after the course, 2] incident reporting cards filled out by course participants during the course, and 3] residents' reporting data gathered from hospital incident reporting systems.</p> <p>Results</p> <p>Forty-four residents attended the course and 32 were external controls. Positive changes in knowledge, skills and attitudes were found after the course. Residents' intentions to report incidents were positive at all measurements. Participants filled out 165 incident reporting cards, demonstrating the skills to notice incidents. Residents who had reported incidents before, reported more incidents after the course. However, the number of residents reporting incidents did not increase. An increase in reported incidents was registered by the reporting system of the intervention hospital.</p> <p>Conclusions</p> <p>Patient safety education can have immediate and long-term positive effects on knowledge, skills and attitudes, and modestly influence the reporting behavior of residents.</p

VEGFR2 pY949 signalling regulates adherens junction integrity and metastatic spread

The specific role of VEGFA-induced permeability and vascular leakage in physiology and pathology has remained unclear. Here we show that VEGFA-induced vascular leakage depends on signalling initiated via the VEGFR2 phosphosite Y949, regulating dynamic c-Src and VE-cadherin phosphorylation. Abolished Y949 signalling in the mouse mutant Vegfr2Y949F/Y949F leads to VEGFA-resistant endothelial adherens junctions and a block in molecular extravasation. Vessels in Vegfr2Y949F/Y949F mice remain sensitive to inflammatory cytokines, and vascular morphology, blood pressure and flow parameters are normal. Tumour-bearing Vegfr2Y949F/Y949F mice display reduced vascular leakage and oedema, improved response to chemotherapy and, importantly, reduced metastatic spread. The inflammatory infiltration in the tumour micro-environment is unaffected. Blocking VEGFAinduced disassembly of endothelial junctions, thereby suppressing tumour oedema and metastatic spread, may be preferable to full vascular suppression in the treatment of certain cancer forms

Jet energy measurement with the ATLAS detector in proton-proton collisions at root s=7 TeV

The jet energy scale and its systematic uncertainty are determined for jets measured with the ATLAS detector at the LHC in proton-proton collision data at a centre-of-mass energy of √s = 7TeV corresponding to an integrated luminosity of 38 pb-1. Jets are reconstructed with the anti-kt algorithm with distance parameters R=0. 4 or R=0. 6. Jet energy and angle corrections are determined from Monte Carlo simulations to calibrate jets with transverse momenta pT≥20 GeV and pseudorapidities {pipe}η{pipe}<4. 5. The jet energy systematic uncertainty is estimated using the single isolated hadron response measured in situ and in test-beams, exploiting the transverse momentum balance between central and forward jets in events with dijet topologies and studying systematic variations in Monte Carlo simulations. The jet energy uncertainty is less than 2. 5 % in the central calorimeter region ({pipe}η{pipe}<0. 8) for jets with 60≤pT<800 GeV, and is maximally 14 % for pT<30 GeV in the most forward region 3. 2≤{pipe}η{pipe}<4. 5. The jet energy is validated for jet transverse momenta up to 1 TeV to the level of a few percent using several in situ techniques by comparing a well-known reference such as the recoiling photon pT, the sum of the transverse momenta of tracks associated to the jet, or a system of low-pT jets recoiling against a high-pT jet. More sophisticated jet calibration schemes are presented based on calorimeter cell energy density weighting or hadronic properties of jets, aiming for an improved jet energy resolution and a reduced flavour dependence of the jet response. The systematic uncertainty of the jet energy determined from a combination of in situ techniques is consistent with the one derived from single hadron response measurements over a wide kinematic range. The nominal corrections and uncertainties are derived for isolated jets in an inclusive sample of high-pT jets. Special cases such as event topologies with close-by jets, or selections of samples with an enhanced content of jets originating from light quarks, heavy quarks or gluons are also discussed and the corresponding uncertainties are determined. © 2013 CERN for the benefit of the ATLAS collaboration

Measurement of the inclusive and dijet cross-sections of b-jets in pp collisions at sqrt(s) = 7 TeV with the ATLAS detector

The inclusive and dijet production cross-sections have been measured for jets containing b-hadrons (b-jets) in proton-proton collisions at a centre-of-mass energy of sqrt(s) = 7 TeV, using the ATLAS detector at the LHC. The measurements use data corresponding to an integrated luminosity of 34 pb^-1. The b-jets are identified using either a lifetime-based method, where secondary decay vertices of b-hadrons in jets are reconstructed using information from the tracking detectors, or a muon-based method where the presence of a muon is used to identify semileptonic decays of b-hadrons inside jets. The inclusive b-jet cross-section is measured as a function of transverse momentum in the range 20 < pT < 400 GeV and rapidity in the range |y| < 2.1. The bbbar-dijet cross-section is measured as a function of the dijet invariant mass in the range 110 < m_jj < 760 GeV, the azimuthal angle difference between the two jets and the angular variable chi in two dijet mass regions. The results are compared with next-to-leading-order QCD predictions. Good agreement is observed between the measured cross-sections and the predictions obtained using POWHEG + Pythia. MC@NLO + Herwig shows good agreement with the measured bbbar-dijet cross-section. However, it does not reproduce the measured inclusive cross-section well, particularly for central b-jets with large transverse momenta.Comment: 10 pages plus author list (21 pages total), 8 figures, 1 table, final version published in European Physical Journal

Do specialty registrars change their attitudes, intentions and behaviour towards reporting incidents following a patient safety course?

<p>Abstract</p> <p>Background</p> <p>Reporting incidents can contribute to safer health care, as an awareness of the weaknesses of a system could be considered as a starting point for improvements. It is believed that patient safety education for specialty registrars could improve their attitudes, intentions and behaviour towards incident reporting. The objective of this study was to examine the effect of a two-day patient safety course on the attitudes, intentions and behaviour concerning the voluntary reporting of incidents by specialty registrars.</p> <p>Methods</p> <p>A patient safety course was designed to increase specialty registrars' knowledge, attitudes and skills in order to recognize and cope with unintended events and unsafe situations at an early stage. Data were collected through an 11-item questionnaire before, immediately after and six months after the course was given.</p> <p>Results</p> <p>The response rate at all three points in time assessed was 100% (n = 33). There were significant changes in incident reporting attitudes and intentions immediately after the course, as well as during follow-up. However, no significant changes were found in incident reporting behaviour.</p> <p>Conclusions</p> <p>It is shown that patient safety education can have long-term positive effects on attitudes towards reporting incidents and the intentions of registrars. However, further efforts need to be undertaken to induce a real change in behaviour.</p