Universal Local symmetries and non-superposition in classical mechanics

In the Hilbert space formulation of classical mechanics (CM), pioneered by Koopman and von Neumann (KvN), there are potentially more observables that in the standard approach to CM. In this paper we show that actually many of those extra observables are not invariant under a set of universal local symmetries which appear once the KvN is extended to include the evolution of differential forms. Because of their non-invariance, those extra observables have to be removed. This removal makes the superposition of states in KvN, and as a consequence also in CM, impossible

Gas-Grain Simulation Facility: Fundamental studies of particle formation and interactions. Volume 2: Abstracts, candidate experiments and feasibility study

An overview of the Gas-Grain Simulation Facility (GGSF) project and its current status is provided. The proceedings of the Gas-Grain Simulation Facility Experiments Workshop are recorded. The goal of the workshop was to define experiments for the GGSF--a small particle microgravity research facility. The workshop addressed the opportunity for performing, in Earth orbit, a wide variety of experiments that involve single small particles (grains) or clouds of particles. Twenty experiments from the fields of exobiology, planetary science, astrophysics, atmospheric science, biology, physics, and chemistry were described at the workshop and are outlined in Volume 2. Each experiment description included specific scientific objectives, an outline of the experimental procedure, and the anticipated GGSF performance requirements. Since these experiments represent the types of studies that will ultimately be proposed for the facility, they will be used to define the general science requirements of the GGSF. Also included in the second volume is a physics feasibility study and abstracts of example Gas-Grain Simulation Facility experiments and related experiments in progress

Gas-Grain Simulation Facility: Fundamental studies of particle formation and interactions. Volume 1: Executive summary and overview

An overview of the Gas-Grain Simulation Facility (GGSF) project and its current status is provided. The proceedings of the Gas-Grain Simulation Facility Experiments Workshop are recorded. The goal of the workshop was to define experiments for the GGSF--a small particle microgravity research facility. The workshop addressed the opportunity for performing, in Earth orbit, a wide variety of experiments that involve single small particles (grains) or clouds of particles. The first volume includes the executive summary, overview, scientific justification, history, and planned development of the Facility

INTRINSIC MECHANISM FOR ENTROPY CHANGE IN CLASSICAL AND QUANTUM EVOLUTION

It is shown that the existence of a time operator in the Liouville space representation of both classical and quantum evolution provides a mechanism for effective entropy change of physical states. In particular, an initially effectively pure state can evolve under the usual unitary evolution to an effectively mixed state.Comment: 20 pages. For more information or comments contact E. Eisenberg at [email protected] (internet)

Quantum dynamics and statistics of two coupled down-conversion processes

In the framework of Heisenberg-Langevin theory the dynamical and statistical effects arising from the linear interaction of two nondegenerate down-conversion processes are investigated. Using the strong-pumping approximation the analytical solution of equations of motion is calculated. The phenomena reminiscent of Zeno and anti-Zeno effects are examined. The possibility of phase-controlled and mismatch-controlled switching is illustrated.Comment: 17 pages, 7 figure

Dislocation screening in crystals with spherical topology

Whereas disclination defects are energetically prohibitive in two-dimensional flat crystals, their existence is necessary in crystals with spherical topology, such as viral capsids, colloidosomes or fullerenes. Such a geometrical frustration gives rise to large elastic stresses, which render the crystal unstable when its size is significantly larger than the typical lattice spacing. Depending on the compliance of the crystal with respect to stretching and bending deformations, these stresses are alleviated by either a local increase of the intrinsic curvature in proximity of the disclinations or by the proliferation of excess dislocations, often organized in the form of one-dimensional chains known as "scars". The associated strain field of the scars is such to counterbalance the one resulting from the isolated disclinations. Here, we develop a continuum theory of dislocation screening in two-dimensional closed crystals with genus one. Upon modeling the flux of scars emanating from a given disclination as an independent scalar field, we demonstrate that the elastic energy of closed two-dimensional crystals with various degrees of asphericity can be expressed as a simple quadratic function of the screened topological charge of the disclinations, both at zero and finite temperature. This allows us to predict the optimal density of the excess dislocations as well as the minimal stretching energy attained by the crystal

Exponential behavior of a quantum system in a macroscopic medium

An exponential behavior at all times is derived for a solvable dynamical model in the weak-coupling, macroscopic limit. Some implications for the quantum measurement problem are discussed, in particular in connection with dissipation.Comment: 8 pages, report BA-TH/94-17

An Integrated XRF/XRD Instrument for Mars Exobiology and Geology Experiments

By employing an integrated x-ray instrument on a future Mars mission, data obtained will greatly augment those returned by Viking; details characterizing the past and present environment on Mars and those relevant to the possibility of the origin and evolution of life will be acquired. A combined x-ray fluorescence/x-ray diffraction (XRF/XRD) instrument was breadboarded and demonstrated to accommodate important exobiology and geology experiment objectives outlined for MESUR and future Mars missions. Among others, primary objectives for the exploration of Mars include the intense study of local areas on Mars to establish the chemical, mineralogical, and petrological character of different components of the surface material; to determine the distribution, abundance, and sources and sinks of volatile materials, including an assessment of the biologic potential, now and during past epoches; and to establish the global chemical and physical characteristics of the Martian surface. The XRF/XRD breadboard instrument identifies and quantifies soil surface elemental, mineralogical, and petrological characteristics and acquires data necessary to address questions on volatile abundance and distribution. Additionally, the breadboard is able to characterize the biogenic element constituents of soil samples providing information on the biologic potential of the Mars environment. Preliminary breadboard experiments confirmed the fundamental instrument design approach and measurement performance

Outcomes of patient education in adult oncologic patients receiving oral anticancer agents: a systematic review protocol

Background: A large variety of oral anticancer agents have become available and while at first glance these therapies appear to provide only benefits, patients have expressed their need for educational interventions and raised safety issues. Although both patients and providers have recognized patient education’s importance, and an interplay with safety has been acknowledged, no systematic reviews of the literature that summarize all of the current evidence related to patient education’s outcomes for patients who receive oral anticancer agents have been performed to date. Accordingly, this systematic review will attempt to fill the gap in the literature as well as to map (1) contents, (2) methodologies, (3) settings, (4) timing/duration, and (5) healthcare professionals involved. Methods: This protocol is being reported in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. A systematic review will be performed. Studies that targeted eligible adult patients (≥ 18 years old) in hospital, outpatient, and home settings, and reported patient education’s outcomes for those taking oral anticancer agents will be included. Searches will be conducted in PubMed/MEDLINE, CINAHL, Embase, and Scopus, and gray literature will be also sought. Two researchers will screen the search results independently and blindly in two phases: (1) title/abstract screening and (2) full-text screening using the Rayyan AI platform. An electronic data extraction form will be implemented and piloted, and then, two trained data extractors will extract the data cooperatively. Thereafter, a quality appraisal will be conducted using the Critical Appraisal Tools from The Joanna Briggs Institute. The results will be analyzed, grouped, clustered into categories, and discussed until a consensus is reached. Emerging evidence will be synthesized narratively and reported in accordance with the synthesis without meta-analysis guidelines. Discussion: The systematic review’s results will be relevant to (1) policymakers and management at an institutional level, and (2) for clinical practice, in an evidence-based paradigm, potentially leading to a quality improvement with respect to safety and patient satisfaction. Systematic review registration: PROSPERO CRD42022341797