Pseudacris clarkii

Number of Pages: 3Integrative BiologyGeological Science

A Step-indexed Semantics of Imperative Objects

Step-indexed semantic interpretations of types were proposed as an alternative to purely syntactic proofs of type safety using subject reduction. The types are interpreted as sets of values indexed by the number of computation steps for which these values are guaranteed to behave like proper elements of the type. Building on work by Ahmed, Appel and others, we introduce a step-indexed semantics for the imperative object calculus of Abadi and Cardelli. Providing a semantic account of this calculus using more `traditional', domain-theoretic approaches has proved challenging due to the combination of dynamically allocated objects, higher-order store, and an expressive type system. Here we show that, using step-indexing, one can interpret a rich type discipline with object types, subtyping, recursive and bounded quantified types in the presence of state

Tacting of Function in College Student Mental Health: An Online and App-Based Approach to Psychological Flexibility

Mental and emotional health concerns among college students are prevalent and diverse in their symptom presentations. With increasing demands on counseling centers to provide efficient care and to address students with higher acuity or risk for harm, there has been an increased focus on identifying therapeutic targets that underlie a wide breadth of concerns to broaden the scope and impact of mental health services. Psychological inflexibility is one such target and refers to a combination of excessive avoidance of internal experiences coupled with a lack of actions that align with a person’s values. Interventions for psychological inflexibility aim to support people in reducing actions that are mostly about avoiding unwanted thoughts and feelings and actions that involve moving towards chosen values. Such interventions may produce changes in people’s actions in part through helping people notice and label the different roles their actions play in relation to thoughts, feelings, and personal values. However, the skill of noticing and labeling the purposes of one’s actions has not been studied in interventions for psychological inflexibility despite being discussed in theoretical writings. Training this skill may serve as a direct means of reducing psychological inflexibility and as a foundation for other interventions, thus it may be a relevant target in interventions for psychological inflexibility among college students. Given this, the present study developed and tested an intervention focused on noticing and labeling one’s actions as an intervention for psychological inflexibility in a college student sample, as delivered through web and app-based media. The study recruited 106 students with symptoms of depression and anxiety from a medium sized university in the Mountain West of the United States, and then randomly assigned them to either wait for eight weeks or receive a three-week online and app-based training for noticing and labeling avoidant and values-consistent actions. The results of the study indicated short-term effects on symptoms of depression and anxiety for participants who received the online and app-based training as compared with participants who were asked to wait, although both groups showed reductions in symptoms by the end of the study period. Participants did not report changes in the target skill of noticing and labeling their actions although the study did find larger reductions in psychological inflexibility among participants who received the training as compared with those asked to wait. Further, changes in psychological flexibility were related to changes in behavioral activity and life satisfaction, but not life quality. The results raise questions about the necessity of training the ability to notice and label one’s actions as a direct intervention mechanism for psychological inflexibility. The findings also suggest that changing inflexible patterns of behavior may be more important than the capacity to notice such changes. These results are further interpreted in relation to interventions for college student mental and emotional health

Higher-order subtyping

AbstractSystem F⩽ω is an extension with subtyping of the higher-order polymorphic λ-calculus —an orthogonal combination of Girard's system Fω with Cardelli and Wegner's Kernel Fun variant of System F⩽. We develop the fundamental metatheory of this calculus: decidability of β-conversion on well-kinded types, elimination of the “cut-rule” of transitivity from the subtype relation, and the soundness, completeness, and termination of algorithms for subtyping and typechecking

The acceptance and commitment therapy matrix mobile app: A pilot randomized trial on health behaviors

Mobile apps provide a promising format for delivering acceptance and commitment therapy (ACT) to improve diet/exercise. This pilot trial evaluated a novel ACT-based app for health behaviors based on the matrix approach. A sample of 23 community adults were randomly assigned to use the app for two weeks or to a waitlist condition. Findings indicated a high degree of satisfaction with the app and acceptable adherence. Although the intent-to-treat sample indicated few intervention effects, when focusing on program engagers only, health behaviors significantly improved in the app condition relative to waitlist. There were no differences between conditions on valued action or experiential avoidance. However, the rate of valued actions increased over days using the app. This was moderated by baseline values and experiential avoidance, suggesting those more psychologically flexible benefit more from the matrix app. An ACT matrix app appears promising for improving health behaviors, but additional revisions and research is needed

On Inner Classes

AbstractInner classes in object-oriented languages play a role similar to nested function definitions in functional languages, allowing an object to export other objects that have direct access to its own methods and instance variables. However, the similarity is deceptive: a close look at inner classes reveals significant subtleties arising from their interactions with inheritance. The goal of this work is a precise understanding of the essential features of inner classes; our object of study is a fragment of Java with inner classes and inheritance (and almost nothing else). We begin by giving a direct reduction semantics for this language. We then give an alternative semantics by translation into a yet smaller language with only top-level classes, closely following Java's Inner Classes Specification. We prove that the two semantics coincide, in the sense that translation commutes with reduction, and that both are type-safe

Decoding Choice Encodings

We study two encodings of the asynchronous pi-calculus with input-guarded choice into its choice-free fragment. One encoding is divergence-free, but refines the atomic commitment of choice into gradual commitment. The other preserves atomicity, but introduces divergence. The divergent encoding is fully abstract with respect to weak bisimulation, but the more natural divergence-free encoding is not. Instead, we show that it is fully abstract with respect to coupled simulation, a slightly coarser - but still coinductively defined - equivalence that does not enforce bisimilarity of internal branching decisions. The correctness proofs for the two choice encodings introduce a novel proof technique exploiting the properties of explicit decodings from translations to source terms