3,433 research outputs found

    An Algebraic Jost-Schroer Theorem for Massive Theories

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    We consider a purely massive local relativistic quantum theory specified by a family of von Neumann algebras indexed by the space-time regions. We assume that, affiliated with the algebras associated to wedge regions, there are operators which create only single particle states from the vacuum (so-called polarization-free generators) and are well-behaved under the space-time translations. Strengthening a result of Borchers, Buchholz and Schroer, we show that then the theory is unitarily equivalent to that of a free field for the corresponding particle type. We admit particles with any spin and localization of the charge in space-like cones, thereby covering the case of string-localized covariant quantum fields.Comment: 21 pages. The second (and crucial) hypothesis of the theorem has been relaxed and clarified, thanks to the stimulus of an anonymous referee. (The polarization-free generators associated with wedge regions, which always exist, are assumed to be temperate.

    Nurses\u27 Alumnae Association Bulletin - Volume 16 Number 1

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    Alumnae Notes ANA Biennial Convention Cancer of the Cervix, Uterus and Ovaries Committee Reports Digest of Alumnae Association Meetings Greetings from Miss Childs Greetings from the President Graduation Awards - 1950 Isotopes and the Nurse - Dr. T.P. Eberhard Marriages Necrology New Arrivals Nursing Care in Heart Disease with Pulmonary Infarction Nursing Care of a Mitral Commissurotomy Physical Advances at Jefferson - 1950 Policies of the Private Duty Nurses\u27 Registry Staff Activities, 1950-1951 Students\u27 Corner The Department of Surgical Research - Drs. Templeton and Gibbon White Haven and Barton Memorial Division

    Evaluating the effects of bilingual traffic signs on driver performance and safety

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    Variable Message Signs (VMS) can provide immediate and relevant information to road users and bilingual VMS can provide great flexibility in countries where a significant proportion of the population speak an alternative language to the majority. The study reported here evaluates the effect of various bilingual VMS configurations on driver behaviour and safety. The aim of the study was to determine whether or not the visual distraction associated with bilingual VMS signs of different configurations (length, complexity) impacted on driving performance. A driving simulator was used to allow full control over the scenarios, road environment and sign configuration and both longitudinal and lateral driver performance was assessed. Drivers were able to read one and two-line monolingual signs and two-line bilingual signs without disruption to their driving behaviour. However, drivers significantly reduced their speed in order to read four-line monolingual and four-line bilingual signs, accompanied by an increase in headway to the vehicle in front. This implies that drivers are possibly reading the irrelevant text on the bilingual sign and various methods for reducing this effect are discussed

    Remarks on Causality in Relativistic Quantum Field Theory

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    It is shown that the correlations predicted by relativistic quantum field theory in locally normal states between projections in local von Neumann algebras \cA(V_1),\cA(V_2) associated with spacelike separated spacetime regions V1,V2V_1,V_2 have a (Reichenbachian) common cause located in the union of the backward light cones of V1V_1 and V2V_2. Further comments on causality and independence in quantum field theory are made.Comment: 10 pages, Latex, Quantum Structures 2002 Conference Proceedings submission. Minor revision of the order of definitions on p.

    Gesture analysis for physics education researchers

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    Systematic observations of student gestures can not only fill in gaps in students' verbal expressions, but can also offer valuable information about student ideas, including their source, their novelty to the speaker, and their construction in real time. This paper provides a review of the research in gesture analysis that is most relevant to physics education researchers and illustrates gesture analysis for the purpose of better understanding student thinking about physics.Comment: 14 page

    Teleology and Realism in Leibniz's Philosophy of Science

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    This paper argues for an interpretation of Leibniz’s claim that physics requires both mechanical and teleological principles as a view regarding the interpretation of physical theories. Granting that Leibniz’s fundamental ontology remains non-physical, or mentalistic, it argues that teleological principles nevertheless ground a realist commitment about mechanical descriptions of phenomena. The empirical results of the new sciences, according to Leibniz, have genuine truth conditions: there is a fact of the matter about the regularities observed in experience. Taking this stance, however, requires bringing non-empirical reasons to bear upon mechanical causal claims. This paper first evaluates extant interpretations of Leibniz’s thesis that there are two realms in physics as describing parallel, self-sufficient sets of laws. It then examines Leibniz’s use of teleological principles to interpret scientific results in the context of his interventions in debates in seventeenth-century kinematic theory, and in the teaching of Copernicanism. Leibniz’s use of the principle of continuity and the principle of simplicity, for instance, reveal an underlying commitment to the truth-aptness, or approximate truth-aptness, of the new natural sciences. The paper concludes with a brief remark on the relation between metaphysics, theology, and physics in Leibniz

    On Vanishing Theorems For Vector Bundle Valued p-Forms And Their Applications

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    Let F:[0,)[0,)F: [0, \infty) \to [0, \infty) be a strictly increasing C2C^2 function with F(0)=0F(0)=0. We unify the concepts of FF-harmonic maps, minimal hypersurfaces, maximal spacelike hypersurfaces, and Yang-Mills Fields, and introduce FF-Yang-Mills fields, FF-degree, FF-lower degree, and generalized Yang-Mills-Born-Infeld fields (with the plus sign or with the minus sign) on manifolds. When F(t)=t,1p(2t)p2,1+2t1,F(t)=t, \frac 1p(2t)^{\frac p2}, \sqrt{1+2t} -1, and 112t,1-\sqrt{1-2t}, the FF-Yang-Mills field becomes an ordinary Yang-Mills field, pp-Yang-Mills field, a generalized Yang-Mills-Born-Infeld field with the plus sign, and a generalized Yang-Mills-Born-Infeld field with the minus sign on a manifold respectively. We also introduce the EF,gE_{F,g}-energy functional (resp. FF-Yang-Mills functional) and derive the first variational formula of the EF,gE_{F,g}-energy functional (resp. FF-Yang-Mills functional) with applications. In a more general frame, we use a unified method to study the stress-energy tensors that arise from calculating the rate of change of various functionals when the metric of the domain or base manifold is changed. These stress-energy tensors, linked to FF-conservation laws yield monotonicity formulae. A "macroscopic" version of these monotonicity inequalities enables us to derive some Liouville type results and vanishing theorems for pp-forms with values in vector bundles, and to investigate constant Dirichlet boundary value problems for 1-forms. In particular, we obtain Liouville theorems for FF-harmonic maps (e.g. pp-harmonic maps), and FF-Yang-Mills fields (e.g. generalized Yang-Mills-Born-Infeld fields on manifolds). We also obtain generalized Chern type results for constant mean curvature type equations for pp-forms on Rm\Bbb{R}^m and on manifolds MM with the global doubling property by a different approach. The case p=0p=0 and M=RmM=\mathbb{R}^m is due to Chern.Comment: 1. This is a revised version with several new sections and an appendix that will appear in Communications in Mathematical Physics. 2. A "microscopic" approach to some of these monotonicity formulae leads to celebrated blow-up techniques and regularity theory in geometric measure theory. 3. Our unique solution of the Dirichlet problems generalizes the work of Karcher and Wood on harmonic map

    Measurement of Angular Distributions and R= sigma_L/sigma_T in Diffractive Electroproduction of rho^0 Mesons

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    Production and decay angular distributions were extracted from measurements of exclusive electroproduction of the rho^0(770) meson over a range in the virtual photon negative four-momentum squared 0.5< Q^2 <4 GeV^2 and the photon-nucleon invariant mass range 3.8< W <6.5 GeV. The experiment was performed with the HERMES spectrometer, using a longitudinally polarized positron beam and a ^3He gas target internal to the HERA e^{+-} storage ring. The event sample combines rho^0 mesons produced incoherently off individual nucleons and coherently off the nucleus as a whole. The distributions in one production angle and two angles describing the rho^0 -> pi+ pi- decay yielded measurements of eight elements of the spin-density matrix, including one that had not been measured before. The results are consistent with the dominance of helicity-conserving amplitudes and natural parity exchange. The improved precision achieved at 47 GeV, reveals evidence for an energy dependence in the ratio R of the longitudinal to transverse cross sections at constant Q^2.Comment: 15 pages, 15 embedded figures, LaTeX for SVJour(epj) document class Revision: Fig. 15 corrected, recent data added to Figs. 10,12,14,15; minor changes to tex

    Reducing Rehospitalizations through Automated Alerts to Primary Care Providers and Staff When Older Patients are Discharged from the Hospital: A Randomized Trial

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    Background: Inadequate continuity of care places older patients at very high risk during transitions from the hospital to ambulatory setting. Methods: We conducted a randomized controlled trial of an HIT-based transitional care intervention in patients aged 65 and older discharged from hospital to home. All patients were senior plan members of a Massachusetts-based health plan, and cared for by a multispecialty medical group using the EpicCare Ambulatory Medical Record. In addition to notifying providers about the patient’s recent transition, the system provided information about new drugs added during the inpatient stay, warnings about drug-drug interactions, recommendations for dose changes and laboratory monitoring of high-risk medications, and reminded the primary care provider’s support staff to schedule a post-hospitalization office visit. Randomization occurred at the time of hospital discharge during a one-year intervention period beginning in August 2010. Alerts were automatically delivered to the provider and staff in-basket within the EMR. The primary outcomes were: 1) having an outpatient office visit with the primary care provider within 30 days following discharge; and 2) having a rehospitalization within 30 days following discharge. Results: The study included 3667 discharges of which 1877 discharges were randomly assigned to the intervention arm. Forty-nine percent of discharges in the intervention arm were followed by office visits with the primary care provider within 30 days, compared to 51% in the comparison arm (RR 0.96, 95% CI 0.90, 1.03). Eighteen percent of discharges in the intervention arm were followed by a rehospitalization within 30 days compared to 20% in the comparison arm (RR 0.92, 95% CI 0.80, 1.05). Conclusions: This HIT-based intervention was not effective in increasing the percentage of hospital discharges of older patients that were followed by timely office visits to primary care providers or reducing the percentage with rehospitalization

    Adverse Drug Events Post-Hospital Discharge in Older Patients: Types, Severity, and Involvement of Beers Criteria Medications

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    Objective: To characterize adverse drug events (ADEs) occurring within the high-risk 45-day period post-hospitalization in older adults. Design: Clinical pharmacists reviewed the ambulatory records of 1000 consecutive discharges. Setting: A large multispecialty group practice closely aligned with a Massachusetts-based health plan. Participants: Hospitalized patients aged 65 years and older who were discharged to home. Measurements: Possible drug-related incidents occurring during the 45-day period post-hospitalization were identified and presented to a pair of physician-reviewers who classified incidents as to whether an ADE was present, whether the event was preventable, and the severity of the event. Medications implicated in ADEs were further characterized according to their inclusion in the 2012 Beers Criteria for Potentially Inappropriate Medication Use in Older Adults. Results: At least one ADE was identified during the 45-day period in 18.7% (187) of the 1000 discharges. Of the 242 ADEs identified, 35% (n=84) were deemed preventable, of which 32% (n=27) were characterized as serious, and 5% (n=4) as life threatening. Over half of all ADEs occurred within the first 14 days post-hospitalization. The percentage of ADEs in which Beers Criteria medications were implicated was 16.5% (n=40). Beers Criteria medications with both a high quality of evidence and strong strength of recommendation were implicated in 6.6% (n=16) of the ADEs. Conclusion: ADEs are common and often preventable among older adults following hospital discharge, underscoring the need to address medication safety during this high-risk period in this vulnerable population. Beers Criteria medications played a small role in these events suggesting that efforts to improve the quality and safety of medication use during this critical transition period must extend beyond a singular focus on Beers criteria medications
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