Toward Semantic Foundations for Program Editors

Programming language definitions assign formal meaning to complete programs. Programmers, however, spend a substantial amount of time interacting with incomplete programs - programs with holes, type inconsistencies and binding inconsistencies - using tools like program editors and live programming environments (which interleave editing and evaluation). Semanticists have done comparatively little to formally characterize (1) the static and dynamic semantics of incomplete programs; (2) the actions available to programmers as they edit and inspect incomplete programs; and (3) the behavior of editor services that suggest likely edit actions to the programmer based on semantic information extracted from the incomplete program being edited, and from programs that the system has encountered in the past. This paper serves as a vision statement for a research program that seeks to develop these "missing" semantic foundations. Our hope is that these contributions, which will take the form of a series of simple formal calculi equipped with a tractable metatheory, will guide the design of a variety of current and future interactive programming tools, much as various lambda calculi have guided modern language designs. Our own research will apply these principles in the design of Hazel, an experimental live lab notebook programming environment designed for data science tasks. We plan to co-design the Hazel language with the editor so that we can explore concepts such as edit-time semantic conflict resolution mechanisms and mechanisms that allow library providers to install library-specific editor services

Nutraceutical and pharmaceutical cocktails did not improve muscle function or reduce histological damage in D2-mdx mice

Progressive muscle injury and weakness are hallmarks of Duchenne muscular dystrophy. We showed previously that quercetin (Q) partially protected dystrophic limb muscles from disease-related injury. As quercetin activates PGC-1α through Sirtuin-1, an NAD+-dependent deacetylase, the depleted NAD+ in dystrophic skeletal muscle may limit quercetin efficacy, hence, supplementation with the NAD+ donor, nicotinamide riboside (NR), may facilitate quercetin efficacy. Lisinopril (Lis) protects skeletal muscle and improves cardiac function in dystrophin-deficient mice, therefore it was included in this study to evaluate the effects of lisinopril used with quercetin and NR. Our purpose was to determine the extent to which Q, NR, and Lis decreased dystrophic injury. We hypothesized that Q, NR or Lis alone would improve muscle function and decrease histological injury and when used in combination would have additive effects. Muscle function of 11-month-old DBA (healthy), D2-mdx (dystrophin-deficient), and D2-mdx mice was assessed following treatment with Q, NR, and/or Lis for 7-months. To mimic typical pharmacology of DMD patients a group was treated with prednisolone (Pred) in combination with Q, NR and Lis. At 11-months of age, dystrophin deficiency decreased specific tension and tetanic force in the soleus and extensor digitorum longus muscles and was not corrected by any treatment. Dystrophic muscle was more sensitive to contraction-induced injury, which was partially offset in the QNRLisPred group, while fatigue was similar between all groups. Treatments did not decrease histological damage. These data suggest treatment with Q, NR, Lis and Pred failed to adequately maintain dystrophic limb muscle function or decrease histological 46 damage

Retina-simulating phantom for optical coherence tomography.

Optical coherence tomography (OCT) is a rapidly growing imaging modality, particularly in the field of ophthalmology. Accurate early diagnosis of diseases requires consistent and validated imaging performance. In contrast to more well-established medical imaging modalities, no standardized test methods currently exist for OCT quality assurance. We developed a retinal phantom which mimics the thickness and near-infrared optical properties of each anatomical retinal layer as well as the surface topography of the foveal pit. The fabrication process involves layer-by-layer spin coating of nanoparticle-embedded silicone films followed by laser micro-etching to modify the surface topography. The thickness of each layer and dimensions of the foveal pit are measured with high precision. The phantom is embedded into a commercially available, water-filled model eye to simulate ocular dispersion and emmetropic refraction, and for ease of use with clinical OCT systems. The phantom was imaged with research and clinical OCT systems to assess image quality and software accuracy. Our results indicate that this phantom may serve as a useful tool to evaluate and standardize OCT performance

The effects of acute beetroot juice ingestion on upper and lower body muscular power during weightlifting exercise in men

Nitrate-rich beetroot juice (BR) supplementation improves movements with high-velocity and high-power muscle contractions which may be due to enhanced blood flow, oxygenation and contractile function in type II muscle fibers. The literature has focused predominantly on the effects of BR supplementation running and cycling performance, but its efficacy in resistance exercise, a modality that relies on type II muscle fibers, has limited data. Furthermore, it is unknown how supplementation strategies impact the physiological and ergogenic effects of BR during exercise. Therefore, the purpose of this study is to assess whether single or multi-day nitrate ingestion will improve performance and muscle oxygenation during resistance exercise. In a double-blind, randomized crossover design, 14 healthy recreationally active men will report to the laboratory for five occasions over a 4-wk period. On the first visit, participants will undergo a 1 repetition-max (1RM) test for back squat and bench press. Subsequently, participants will complete two 4-day experimental trials where they will consume 2 x 70mL doses per day of either nitrate-depleted placebo (PL) or concentrated nitrate-rich BR. On experimental days of each supplementation period (day 1 and 4), subjects will consume 140 mL of their allocated beverage 2.5-h before exercise. On day 2 and 3 of the supplementation period, participants will consume one 70 mL beverage in the morning and one in the evening. On experimental days, participants performed a power protocol, consisting of 2 sets x 2 repetitions of back squats and bench press at 70%1RM followed by repetition-to-failures at 60%1RM. Muscle oxygenation, power and velocity were assessed during exercise using near infrared spectroscopy and a linear transducer, respectively. A subset of data has been collected (n=9) and data collection is ongoing

The effects of acute beetroot juice ingestion on upper and lower body muscular power during weightlifting exercise in men.

Dietary nitrate supplementation, administered per beetroot juice (BR), has been shown to enhance performance while cycling and running. BR has enhanced skeletal muscle contraction and blood flow within type II fibers which are recruited during high-velocity and high-power contractions. However, it is unknown whether BR influences alternative forms of exercise, such as resistance exercise. The purpose of this study is to assess whether BR supplementation influences neuromuscular performance (muscle power and speed), and repetitions-to-failure in healthy, recreationally active men. In a double-blind, randomized crossover design, 14 males will be recruited to complete two 4-day supplementation periods in which they consume 2 x 70mL nitrate-depleted placebo (PL) or nitrate-rich BR per day. Subjects will report to the lab 5 times over a 3-to 4-wk period. Subjects will complete a 1 repetition max (1RM) test and familiarization to the protocol. On experimental days subjects will complete a warm up and then a protocol to assess explosive performance, consisting of 2 sets x 2 repetitions of back squat at 70% 1RM using a cadence that emphasizes an explosive concentric phase. Skeletal muscle oxygenation will be measured using near-infrared spectroscopy and neuromuscular performance will be measured during exercise using a linear transducer. Following a 5-min recovery period, subjects performed 1 set x repetition-to-failure at 60% 1RM to determine muscular endurance. This protocol will be repeated in the bench press exercise. Data was analyzed in a subset of n = 9. There were no significant differences in resistance exercise performance between conditions; however, data collection is ongoing and results are currently underpowered. These data could provide insight for dietary nitrate as an ergogenic aid and inform both supplementation guidelines and recommendations for enhancing resistance training performance in men

How Do Disks Survive Mergers?

We develop a physical model for how galactic disks survive and/or are destroyed in interactions. Based on dynamical arguments, we show gas primarily loses angular momentum to internal torques in a merger. Gas within some characteristic radius (a function of the orbital parameters, mass ratio, and gas fraction of the merging galaxies), will quickly lose angular momentum to the stars sharing the perturbed disk, fall to the center and be consumed in a starburst. A similar analysis predicts where violent relaxation of the stellar disks is efficient. Our model allows us to predict the stellar and gas content that will survive to re-form a disk in the remnant, versus being violently relaxed or contributing to a starburst. We test this in hydrodynamic simulations and find good agreement as a function of mass ratio, orbital parameters, and gas fraction, in simulations spanning a wide range in these properties and others, including different prescriptions for gas physics and feedback. In an immediate sense, the amount of disk that re-forms can be understood in terms of well-understood gravitational physics, independent of details of ISM gas physics or feedback. This allows us to explicitly quantify the requirements for such feedback to (indirectly) enable disk survival, by changing the pre-merger gas content and distribution. The efficiency of disk destruction is a strong function of gas content: we show how and why sufficiently gas-rich major mergers can, under general conditions, yield systems with small bulges (B/T<0.2). We provide prescriptions for inclusion of our results in semi-analytic models.Comment: 32 pages, 16 figures, accepted to ApJ (minor revisions to match accepted version