7,940 research outputs found
Neutrix Calculus and Finite Quantum Field Theory
In general, quantum field theories (QFT) require regularizations and infinite
renormalizations due to ultraviolet divergences in their loop calculations.
Furthermore, perturbation series in theories like QED are not convergent
series, but are asymptotic series. We apply neutrix calculus, developed in
connection with asymptotic series and divergent integrals, to QFT,obtaining
finite renormalizations. While none of the physically measurable results in
renormalizable QFT is changed, quantum gravity is rendered more manageable in
the neutrix framework.Comment: 10 pages; LaTeX; version to appear in J. Phys. A: Math. Gen. as a
Letter to the Edito
Evaluation of an adaptive implementation program for Cognitive Adaptation Training for people with severe mental illness:Protocol for a randomized controlled trial
Background: Cognitive Adaptation Training is a psychosocial intervention that focuses on reducing the negative effects of cognitive disorders, especially executive functions such as planning and targeted action. International research has shown that Cognitive Adaptation Training enhances multiple aspects of daily functioning in people with severe mental illnesses. Despite this evidence, implementation of the intervention into routine care remains a challenge. Objective: In this implementation research, a newly developed implementation program based on previous experience and scientific literature, is tested. The primary aim of this research is to assess the effectiveness of the implementation program. The secondary aim of this study is to evaluate the factors that impede or facilitate the implementation of Cognitive Adaptation Training. Methods: To test the effectiveness of the implementation program, a multicenter cluster randomized controlled trial was conducted comparing the implementation program to a single training program in four mental health institutions in The Netherlands. Focus groups, semistructured interviews, and questionnaires were used at multiple levels of service delivery (service user, professional, team, organization) to identify factors that may hamper or facilitate implementation. The RE-AIM framework was applied to measure the implementation effectiveness. Following this framework, the primary outcomes were Reach, Intervention Effectiveness, Adoption, Implementation, and Maintenance. These are assessed before, during, and after implementation. The research had a total duration of 14 months, with a follow-up measurement at 14 months. Data will be analyzed using multilevel modeling. Results: The study was funded in April 2018. Data collection occurred between November 2018 and January 2020. In total, 21 teams of 4 mental health institutions agreed to participate. Data analysis is ongoing and results are expected to be published in December 2020. Conclusions: This implementation research may provide important information about the implementation of psychosocial interventions in practice and may result in a program that is useful for Cognitive Adaptation Training, and possibly for psychosocial interventions in general. Trial registration: The Netherlands Trial Register (NL7989); https://www.trialregister.nl/trial/7989. International Registered Report Identifier (IRRID): DERR1-10.2196/17412
Classical and Quantum Annealing in the Median of Three Satisfiability
We determine the classical and quantum complexities of a specific ensemble of
three-satisfiability problems with a unique satisfying assignment for up to
N=100 and N=80 variables, respectively. In the classical limit we employ
generalized ensemble techniques and measure the time that a Markovian Monte
Carlo process spends in searching classical ground states. In the quantum limit
we determine the maximum finite correlation length along a quantum adiabatic
trajectory determined by the linear sweep of the adiabatic control parameter in
the Hamiltonian composed of the problem Hamiltonian and the constant transverse
field Hamiltonian. In the median of our ensemble both complexities diverge
exponentially with the number of variables. Hence, standard, conventional
adiabatic quantum computation fails to reduce the computational complexity to
polynomial. Moreover, the growth-rate constant in the quantum limit is 3.8
times as large as the one in the classical limit, making classical fluctuations
more beneficial than quantum fluctuations in ground-state searches
āHereās My Dilemmaā. Moral Case Deliberation as a Platform for Discussing Everyday Ethics in Elderly Care
Our study presents an overview of the issues that were brought forward by participants of a moral case deliberation (MCD) project in two elderly care organizations. The overview was inductively derived from all case descriptions (NĀ =Ā 202) provided by participants of seven mixed MCD groups, consisting of care providers from various professional backgrounds, from nursing assistant to physician. The MCD groups were part of a larger MCD project within two care institutions (residential homes and nursing homes). Care providers are confronted with a wide variety of largely everyday ethical issues. We distinguished three main categories: āresidentās behaviorā, ādivergent perspectives on good careā and āorganizational contextā. The overview can be used for agendasetting when institutions wish to stimulate reflection and deliberation. It is important that an agenda is constructed from the bottom-up and open to a variety of issues. In addition, organizing reflection and deliberation requires effort to identify moral questions in practice whilst at the same time maintaining the connection with the organizational context and existing communication structures. Once care providers are used to dealing with divergent perspectives, inviting different perspectives (e.g. family members) to take part in the deliberation, might help to identify and address ethical āblind spotsā
The relation of 12 lead ECG to the cardiac anatomy: The normal CineECG.
Abstract Background The interpretation of the 12ālead ECG is notoriously difficult and requires experts to distinguish normal from abnormal ECG waveforms. ECG waveforms depend on body build and electrode positions, both often different in males and females. To relate the ECG waveforms to cardiac anatomical structures is even more difficult. The novel CineECG algorithm enables a direct projection of the 12ālead ECG to the cardiac anatomy by computing the mean location of cardiac activity over time. The aim of this study is to investigate the cardiac locations of the CineECG derived from standard 12ālead ECGs of normal subjects. Methods In this study we used 6525 12ālead ECG tracings labelled as normal obtained from the certified Physionet PTB XL Diagnostic ECG Database to construct the CineECG. All 12 lead ECGs were analyzed, and then divided by age groups (18ā29,30-39,40-49,50-59,60-69,70ā100 years) and by gender (male/female). For each ECG, we computed the CineECG within a generic 3D heart/torso model. Based on these CineECG's, the average normal cardiac location and direction for QRS, STpeak, and TpeakTend segments were determined. Results The CineECG direction for the QRS segment showed large variation towards the left free wall, whereas the STT segments were homogeneously directed towards the septal/apical region. The differences in the CineECG location for the QRS, STpeak, and TpeakTend between the age and gender groups were relatively small (maximally 10 mm at end T-wave), although between the gender groups minor differences were found in the 4 chamber direction angles (QRS 4Ā°, STpeak 5Ā°, and TpeakTend 8Ā°) and LAO (QRS 1Ā°, STpeak 13Ā°, and TpeakTend 30Ā°). Conclusion CineECG demonstrated to be a feasible and pragmatic solution for ECG waveform interpretation, relating the ECG directly to the cardiac anatomy. The variations in depolarization and repolarization CineECG were small within this group of normal healthy controls, both in cardiac location as well as in direction. CineECG may enable an easier discrimination between normal and abnormal QRS and T-wave morphologies, reducing the amount of expert training. Further studies are needed to prove whether novel CineECG can significantly contribute to the discrimination of normal versus abnormal ECG tracings
Role of Adiposity and Lifestyle in the Relationship Between Family History of Diabetes and 20-Year Incidence of Type 2 Diabetes in U.S. Women
OBJECTIVE - To evaluate to what extent the association between family history of diabetes and risk of type 2 diabetes can be explained by excess adiposity and lifestyle risk factors. RESEARCH DESIGN AND METHODS - We analyzed data from 73,227 women who participated in the Nurses' Health Study cohort. A family history of diabetes was defined as having at least one first-degree family member with diabetes. Lifestyle factors, weight, and height were assessed by using validated questionnaires, and BMI was calculated. The relative risk of type 2 diabetes was estimated using Cox proportional hazards analysis. RESULTS - We documented 5,101 cases of type 2 diabetes during 20 years of follow-up. The age-adjusted relative risk of type 2 diabetes in participants with a family history was 2.27 (95% CI 2.14-2.40) compared with the risk in those without a family history of diabetes. Participants with a family history of diabetes had a higher BMI and were more likely to have a parental history of obesity. BMI explained 21.1% (19.4-22.9) of the association between family history of diabetes and risk of type 2 diabetes. Intakes of red meat, alcohol, and sugar-sweetened beverages explained 1.1% (0.8-1.3), 4.8% (4.3-5.3), and 2.8% (2.4-3.2) of this association, respectively. CONCLUSIONS - These results suggest that excess adiposity and, to a lesser extent, specific dietary habits can explain a substantial part of the association between having a family history of diabetes and risk of type 2 diabetes. Ā© 2010 by the American Diabetes Association
Prognostic factors and patterns of recurrence in esophageal cancer assert arguments for extended two-field transthoracic esophagectomy
BACKGROUND: High recurrence rates determine the dismal outcome in esophageal cancer. We reviewed our experiences and defined prognostic factors and patterns of recurrences after curatively, intended transthoracic esophagectomy. METHODS: Between January 1991 and December 2005, 212 consecutive patients underwent a radical transthoracic esophagectomy with extended 2-field lymphadenectomy. Recurrence rates, survival, and prognostic factors were analyzed (minimal follow-up period, 2 y). RESULTS: Radicality was obtained in 85.6%. The median follow-up period was 26.6 months. The overall recurrence rate at I, 3, and 5 years was 28%, 44%, and 64%, respectively, and locoregional recurrence rate was 17%, 27%, and 43%, respectively. Overall survival rates, including postoperative deaths, were 45% and 34% at 3 and 5 years, respectively. pT stage and lymph node (LN) ratio greater than .20 were independent prognostic factors for survival and recurrences. Radicality was most prognostic for survival, and for N+ greater than 4 positive LN for recurrences. CONCLUSIONS: Radicality and LN ratio are strong prognostic factors. High radicality and adequate nodal assessment are guaranteed by an extended transthoracic approach. (C) 2010 Elsevier Inc. All rights reserved
On SIC-POVMs in Prime Dimensions
The generalized Pauli group and its normalizer, the Clifford group, have a
rich mathematical structure which is relevant to the problem of constructing
symmetric informationally complete POVMs (SIC-POVMs). To date, almost every
known SIC-POVM fiducial vector is an eigenstate of a "canonical" unitary in the
Clifford group. I show that every canonical unitary in prime dimensions p > 3
lies in the same conjugacy class of the Clifford group and give a class
representative for all such dimensions. It follows that if even one such
SIC-POVM fiducial vector is an eigenvector of such a unitary, then all of them
are (for a given such dimension). I also conjecture that in all dimensions d,
the number of conjugacy classes is bounded above by 3 and depends only on d mod
9, and I support this claim with computer computations in all dimensions < 48.Comment: 6 pages, no figures. v3 Refs added, improved discussion of previous
work. Ref to a proof of the main conjecture also adde
Noise Thresholds for Higher Dimensional Systems using the Discrete Wigner Function
For a quantum computer acting on d-dimensional systems, we analyze the
computational power of circuits wherein stabilizer operations are perfect and
we allow access to imperfect non-stabilizer states or operations. If the noise
rate affecting the non-stabilizer resource is sufficiently high, then these
states and operations can become simulable in the sense of the Gottesman-Knill
theorem, reducing the overall power of the circuit to no better than classical.
In this paper we find the depolarizing noise rate at which this happens, and
consequently the most robust non-stabilizer states and non-Clifford gates. In
doing so, we make use of the discrete Wigner function and derive facets of the
so-called qudit Clifford polytope i.e. the inequalities defining the convex
hull of all qudit Clifford gates. Our results for robust states are provably
optimal. For robust gates we find a critical noise rate that, as dimension
increases, rapidly approaches the the theoretical optimum of 100%. Some
connections with the question of qudit magic state distillation are discussed.Comment: 14 pages, 1 table; Minor changes vs. version
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