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Absence of finite temperature phase transitions in the X-Cube model and its Zp generalization
No full textWe investigate thermal properties of the X-Cube model and its Zp \clocktype" (pX-Cube) extension. In the latter, the elementary spin-1/2 operators of the X-Cube model are replaced by elements of the Weyl algebra. We study dierent boundary condition realizations of these models and analyze their nite temperature dynamics and thermodynamics. We nd that (i) no nite temperature phase transitions occur in these systems. In tandem, employing bond-algebraic dualities, we show that for Glauber type solvable baths, (ii) thermal uctuations might not enable system size dependent time autocorrelations at all positive temperatures (i.e., they are thermally fragile). Qualitatively, our results demonstrate that similar to Kitaev's Toric code model, the X-Cube model (and its p-state clock-type descendants) may be mapped to simple classical Ising (p-state clock) chains in which neither phase transitions nor anomalously slow glassy dynamics might appear
Symbolic Disintegration with a Variety of Base Measures
Get PDFDisintegration is a relation on measures and a transformation on probabilistic programs that generalizes density calculation and conditioning, two operations widely used for exact and approximate inference. Existing program transformations that find a disintegration or density automatically are limited to a fixed base measure that is an independent product of Lebesgue and counting measures, so they are of no help in practical cases that require tricky reasoning about other base measures. We present the first disintegrator that handles variable base measures, including discrete-continuous mixtures, dependent products, and disjoint sums. By analogy with type inference, our disintegrator can check a given base measure as well as infer an unknown one that is principal. We derive the disintegrator and prove it sound by equational reasoning from semantic specifications. It succeeds in a variety of applications where disintegration and density calculation had not been previously mechanized
Integration of Sequential Reactions in a Continuous Flow Droplet Reactor: A Route to Architecturally Defined Bimetallic Nanostructures
No full textMicroreactors for nanoparticle (NP) synthesis offer advantages over batch reactions in terms of scale-up and integration with online analyses. Herein, two microreactors (i.e., a duo-microreactor) are integrated to achieve sequential reactions for the synthesis of bimetallic NPs with architectural control. The generality of the duo-microreactor is shown with the synthesis of branched Pd-Pt NPs and core@shell Pd@Au NPs, both achieved by synthesizing Pd nanocubes in the first part of the duomicroreactor and then using those nanocubes downstream as seeds for Pt or Au deposition. Control of the dimensions of these NPs was further demonstrated and achieved by tailoring metal precursor concentrations inline. This microreactor methodology is anticipated to be applicable to other bimetallic NP systems
Magnetization Slow Dynamics in Ferrocenium Complexes
No full textThe Single-Molecule Magnet (SMM) properties of a series of ferrocenium complexes, [Fe(-CR)]+ (R = Me, Bn), are reported. In the presence of an applied dc field, the slow dynamics of the magnetization in [Fe(-CMe)]BAr are revealed. Multireference quantum mechanical calculations show a large energy difference between the ground and first excited states, excluding the commonly invoked, thermally activated (Orbach-like) mechanism of relaxation. In contrast, a detailed analysis of the relaxation time highlights that both direct and Raman processes are responsible for the SMM properties. Similarly, the bulky ferrocenium complexes, [Fe(-CBn)]BF and [Fe(-CBn)]PF, also exhibit magnetization slow dynamics, however an additional relaxation process is clearly detected for these analogous systems
Should a manufacturer sell refurbished returns on the secondary market to incentivize retailers to reduce consumer returns?
No full textConsumer electronics returns are typically returned by the retailer to the manufacturer for a full refund of the wholesale price. This practice does not suciently motivate the retailer to reduce the volume of returns. Dierent mechanisms have been proposed to incentivize the retailer to reduce returns, such as a reduced wholesale price for returns below a target, but they do not consider the subsequent disposition of returns. The high value of returns usually justies refurbishment and resale. We study how competition between refurbished returns sold by the manufacturer and new products sold at the retailer aects retailer behavior. We nd that the retailer never exerts more eort to reduce returns when faced with competition through the online store. The manufacturer's protability, however, is always higher with an online store. The online store is also preferable to a strategy where the manufacturer only partially refunds the retailer for returns
Veine de marbre et veine poétique: Clésinger, Baudelaire et la chair de la Présidente
Get PDFLa Femme piquée par un serpent d’Auguste Clésinger fut l’un des plus gros succès du Salon de 1847, qui s’est tenu au Louvre à partir du 16 mars. Or cette statue de marbre, présentée comme une « étude », ne tarda pas à provoquer un scandale, en donnant lieu à un âpre débat critique. Dans son feuilleton de La Presse du 10 avril, Théophile Gautier salue certes « l’incontestable originalité » de Clésinger, en remarquant que « nul sculpteur n’a embrassé la réalité d’une étreinte plus étroite ». Quant à la statue, Gautier observe que « ce corps frémissant n’est pas sculpté mais pétri; il a le grain de la peau et la fleur de l’épiderme », si bien que le critique en vient à pasticher le pygmalionisme du peintre balzacien Frenhofer face à son « Chef-d’oeuvre inconnu »: « Car elle n’est pas en marbre, elle est en chair; elle n’est pas sculptée, elle vit! elle se tord. Et n’est-ce pas une illusion? elle a remué! Il me semble que si l’on posait la main sur ce corps blanc et souple, au lieu du froid de la pierre, on trouverait la tiédeur de l’existence ». Pourtant, une rumeur ne tarda pas à se répandre selon laquelle la « volupté » se dégageant de la statue de la Femme piquée par un serpent ne serait pas tellement due au talent du sculpteur, mais plutôt au corps même du modèle
Crossing the color line: An examination of mediators and a social media intervention for racial bias in selective exposure to movies
No full textPrevious research has found that White audiences exhibit less preference for movies with minority casts than for movies with White casts. We conducted two experiments to explore why this race-based bias occurs and how to overcome it. In the first study, we examined potential mediators of the relationship between actors’ race and intention to view movies with minority actors. Results indicated that perceptions of the intended audience fully mediated the relationship. The second study manipulated this perception via social media postings. Findings suggest the race bias can be eliminated for White audiences. Specifically, the drop in interest in seeing a movie with a Black cast was erased when Whites read positive comments about the film from other Whites
The interaction between inhibitory control and corrective feedback timing
Get PDFThis article reports a study investigating the role of inhibitory control in the acquisition of Spanish noun-adjective gender agreement under different feedback timing conditions. Forty-three Spanish learners completed a communicative task through synchronous computer-mediated communication. The immediate group received reformulations immediately after their errors, whereas the delayed group received reformulations at the end of the task. The control group did not receive any feedback. Learners’ knowledge of the target form was assessed using oral production and grammaticality judgment tests at three different times: once before the treatment, once immediately after the treatment, and once ten days after the treatment. Inhibitory control was measured with the Flanker test. Results did not show a statistically significant interaction between inhibitory control and feedback timing group on either outcome measure even though the correlations between learners' gains and inhibitory control were different across groups
Consumption and Performance: Understanding Longitudinal Dynamics of Recommender Systems via an Agent-Based Simulation Framework
Get PDFWe develop a general agent-based modeling and computational simulation approach to study the impact of various factors on the temporal dynamics of recommender systems’ performance. The proposed agent-based simulation approach allows for comprehensive analysis of longitudinal recommender systems performance under a variety of diverse conditions, which typically is not feasible with live real-world systems. We specifically focus on exploring the product consumption strategies and show that, over time, userrecommender interactions consistently lead to the longitudinal performance paradox of recommender systems. In particular, users’ reliance on the system’s recommendations to make item choices generally tends to make the recommender system less useful in the long run or, more specifically, negatively impacts the longitudinal dynamics of several important dimensions of recommendation performance. Furthermore, we explore the nuances of the performance paradox via additional explorations of longitudinal dynamics of recommender systems for a variety of user populations, consumption strategies, as well as personalized and non-personalized recommendation approaches. One interesting discovery from our exploration is that a certain hybrid consumption strategy, i.e., where users rely on a combination of both personalized- and popularity-based recommendations, offers a unique ability to substantially improve consumption relevance over time. In other words, for such hybrid consumption settings, recommendation algorithms facilitate the general “quality-risesto- the-top” phenomenon, which is not present in the pure popularity-based consumption. In addition to discussing a number of interesting performance patterns, the paper also analyzes and provides insights into the underlying factors that drive such patterns. Our findings have significant implications for the design and implementation of recommender systems
Key considerations when using health insurance claims data in advanced data analyses: An experience report
Get PDFHealth claims have become a popular source of data for healthcare analytics, with numerous applications ranging from disease burden estimation and policy evaluation to drug event detection and advanced predictive analytics. Independent of the application, a researcher utilizing claims information will likely encounter challenges in using the data, which include dealing with several coding systems and coding irregularities. We highlight some of these challenges and approaches for successful analysis that may reduce implementation time and help in avoiding common pitfalls. We describe the experiences of a group of academic researchers in using an extensive seven-year repository of US medical and pharmaceutical claims data in a research study, and it provides an overview of the challenges encountered with handling claims records for data analysis while sharing suggestions on how to address these challenges. To illustrate our experiences, we use the example of dening episodes of care for a bundled payment reimbursement system in the US context