Fundamental limitations on photoisomerization from thermodynamic resource theories

Small, out-of-equilibrium, and quantum systems defy simple thermodynamic expressions. Such systems are exemplified by molecular switches, which exchange heat with a bath. These molecules can photoisomerize, or change conformation, or switch, upon absorbing light. The photoisomerization probability depends on kinetic details that couple the molecule's energetics to its dissipation. Therefore, a simple, general, thermodynamic-style bound on the photoisomerization probability seems out of reach. We derive such a bound using a resource theory. The resource-theory framework is a set of mathematical tools, developed in quantum information theory, used to generalize thermodynamics to small and quantum settings. From this toolkit has been derived a generalization of the second law, the thermomajorization preorder. We use thermomajorization to upper-bound the photoisomerization probability. Then, we compare the bound with an equilibrium prediction and with a Lindbladian model. We identify a realistic parameter regime in which the Lindbladian evolution saturates the thermomajorization bound. We also quantify the energy coherence in the electronic degree of freedom, and we argue that this coherence cannot promote photoisomerization. This work illustrates how quantum-information-theoretic thermodynamics can elucidate complex quantum processes in nature, experiments, and synthetics.Comment: 8.5 pages. Published versio

Diagnosis of coronary stenosis with CT angiography comparison of automated computer diagnosis with expert readings.

RATIONALE AND OBJECTIVES: To compare computer-generated interpretation of coronary computed tomography angiography (cCTA) by commercially available COR Analyzer software with expert human interpretation. MATERIALS AND METHODS: This retrospective Health Insurance Portability and Accountability Act‑compliant study was approved by the institutional review board. Among 225 consecutive cCTA examinations, 207 were of adequate quality for automated evaluation. COR Analyzer interpretation was compared to human expert interpretation for detection of stenosis defined as ≥50% vessel diameter reduction in the left main, left anterior descending (LAD), circumflex (LCX), right coronary artery (RCA), or a branch vessel (diagonal, ramus, obtuse marginal, or posterior descending artery). RESULTS: Among 207 cases evaluated by COR Analyzer, human expert interpretation identified 48 patients with stenosis. COR Analyzer identified 44/48 patients (sensitivity 92%) with a specificity of 70%, a negative predictive value of 97% and a positive predictive value of 48%. COR Analyzer agreed with the expert interpretation in 75% of patients. With respect to individual segments, COR Analyzer detected 9/10 left main lesions, 33/34 LAD lesions, 14/15 LCX lesions, 27/31 RCA lesions, and 8/11 branch lesions. False-positive interpretations were localized to the left main (n = 16), LAD (n = 26), LCX (n = 21), RCA (n = 21), and branch vessels (n = 23), and were related predominantly to calcified vessels, blurred vessels, misidentification of vessels and myocardial bridges. CONCLUSIONS: Automated computer interpretation of cCTA with COR Analyzer provides high negative predictive value for the diagnosis of coronary disease in major coronary arteries as well as first-order arterial branches. False-positive automated interpretations are related to anatomic and image quality considerations

Observations on short-period internal waves in Massachusetts Bay

Temperature measurements made 9 km west of a prominent sill in Massachusetts Bay indicate that the seasonal thermocline heaves up and down in phase with periods of 6 to 8 minutes for about 2.5 hours during flood tide. A sudden rise in the general temperature level accompanies the onset of the short-period motion...

Constructive Decision Theory

Contemporary approaches to decision making describe a decision problem by sets of states and outcomes, and a rich set of acts: functions from states to outcomes over which the decision maker (DM) has preferences. Real problems do not come so equipped. It is often unclear what the state and outcome spaces would be. We present an alternative foundation for decision making, in which the primitive objects of choice are syntactic programs. We show that if the DM's preference relation on objects of choice satisfies appropriate axioms, then we can find states, outcomes, and an embedding of the programs into Savage acts such that preferences can be represented by EU in the Savage framework. A modeler can test for SEU behavior without having access to the subjective states and outcomes. We illustrate the power of our approach by showing that it can represent DMs who are subject to framing effects.Decision theory, subjective expected utility, behavioral anomalies

Imagination or Repetition? The Possible Role of the Referential Validity Effect in Autobiographical Memory Distortion

Recently a number of researchers have found that asking participants to imagine engaging in unlikely childhood events can increase their estimation that those events actually took place. This "imagination inflation" effect has been assumed to result from the process of imagination. However, this conclusion may be premature since prior studies investigating imagination have been confounded with repetition; i.e., participants receive more exposure to the "target" items (i.e., those items which are imagined) than to the "non-target" items (i.e., those items which are not imagined). Research on the referential validity effect reveals that estimations of the truth of propositions is increased for repeated items relative to items that are presented for the first time. Based on unpublished work investigating the potency of imagination inflation, and on the inherent similarities between the multiple exposures to target items in the imagination inflation paradigm and repetition utilized in studies investigating the validity effect, the current study tested the effects of imagining an item against those of simply being exposed to multiple repetitions of it. Results provided initial support for the hypothesis that repetition is the driving force between differences between targets and non-targets, and that they do not depend on the act of extensive imagination. However, a limitation in the design of this study (whereby control subjects engaged in some imagination, albeit far less that imagination subjects) suggests that the present findings must be viewed with caution. The implications of this limitation are discussed, and potential ways of honing the experimental design are offered