3,016 research outputs found
Mountain winds (revisited)
The prediction of extremely high wind speeds, at ground level on the downstream side of a mountain range, is possible by solving the initial value problem for a two-layered nonlinear shallow water model of the atmosphere. Three different numerical methods are described to find the solutions which may involve shocks: (1) the vonNeumann-Richtmyer artificial viscosity method, (2) a filtering scheme, and (3) a hybrid method
Numerical methods for meteorology and climatology
Efficient numerical methods for long term weather forecasting are developed. One implicit and one explicit scheme are compared as to accuracy
Chaotic root-finding for a small class of polynomials
In this paper we present a new closed-form solution to a chaotic difference equation, with coefficient , and using this solution, show how corresponding exact roots to a special set of related polynomials of order with two independent parameters can be generated, for any
Comfort with Communication in Palliative and End of Life Care (C-COPE)
The C-COPE instrument is based on literature review, content from the COMFORT model, and iterative input from four content experts. The COMFORT communication model is grounded in patient-centered care and narrative medicine, where patients, families, and the healthcare team value each other’s story and collaboratively identify wishes and goals of care. COMFORT communication skills include bearing witness, understanding health literacy, actively listening, understanding family communication patterns, talking through the tension, embracing patient and family goals of care, and learning to collaborate with members of the team. The C-COPE operationalizes the key components of the COMFORT model: Communication, Orientation and opportunity, Mindful presence, Family, Openings, Relating, and Team. The 28-item instrument includes two ranked items and 26 items rated on a 5-point Likert-type scale (1 = not difficult, 2 = slightly difficult, 3 = uncertain, 4 = difficult, 5 = very difficult) to assess healthcare professional comfort with palliative and end-of-life communication. The range of possible C-COPE total scores is 26-130 points, with higher scores indicating less comfort with palliative and end-of-life communication. Rated items were categorized according to patient communication, family communication, and team communication. Preliminary psychometric analysis based on this pilot test of the C-COPE instrument supports test-retest reliability with ICC \u3e 0.77, internal reliability for total score with Cronbach’s alpha = 0.91, and four factors with Cronbach’s alpha ranging from 0.81- 0.90
Information-disturbance tradeoff in estimating a maximally entangled state
We derive the amount of information retrieved by a quantum measurement in
estimating an unknown maximally entangled state, along with the pertaining
disturbance on the state itself. The optimal tradeoff between information and
disturbance is obtained, and a corresponding optimal measurement is provided.Comment: 4 pages. Accepted for publication on Physical Review Letter
Causality re-established
Causality never gained the status of a "law" or "principle" in physics. Some
recent literature even popularized the false idea that causality is a notion
that should be banned from theory. Such misconception relies on an alleged
universality of reversibility of laws of physics, based either on determinism
of classical theory, or on the multiverse interpretation of quantum theory, in
both cases motivated by mere interpretational requirements for realism of the
theory. Here, I will show that a properly defined unambiguous notion of
causality is a theorem of quantum theory, which is also a falsifiable
proposition of the theory. Such causality notion appeared in the literature
within the framework of operational probabilistic theories. It is a genuinely
theoretical notion, corresponding to establish a definite partial order among
events, in the same way as we do by using the future causal cone on Minkowski
space. The causality notion is logically completely independent of the
misidentified concept of "determinism", and, being a consequence of quantum
theory, is ubiquitous in physics. In addition, as classical theory can be
regarded as a restriction of quantum theory, causality holds also in the
classical case, although the determinism of the theory trivializes it. I then
conclude arguing that causality naturally establishes an arrow of time. This
implies that the scenario of the "Block Universe" and the connected "Past
Hypothesis" are incompatible with causality, and thus with quantum theory: they
both are doomed to remain mere interpretations and, as such, not falsifiable,
similar to the hypothesis of "super-determinism". This article is part of a
discussion meeting issue "Foundations of quantum mechanics and their impact on
contemporary society".Comment: Presented at the Royal Society of London, on 11/12/ 2017, at the
conference "Foundations of quantum mechanics and their impact on contemporary
society". To appear on Philosophical Transactions of the Royal Society
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