A gentler way to show suffering

Leslie Knott, an award-winning filmmaker and photographer, is co-founder of Tiger Nest Films, and travels to some of the most unstable regions in world. Knott’s shocking and moving films expose viewers to the largely uncovered humanitarian issues such as the refugee crisis. Polis Summer School student Alexandra Kazerounian reports on her talk to the Polis/LSE Journalism Summer School

Autonomous Reinforcement of Behavioral Sequences in Neural Dynamics

We introduce a dynamic neural algorithm called Dynamic Neural (DN) SARSA(\lambda) for learning a behavioral sequence from delayed reward. DN-SARSA(\lambda) combines Dynamic Field Theory models of behavioral sequence representation, classical reinforcement learning, and a computational neuroscience model of working memory, called Item and Order working memory, which serves as an eligibility trace. DN-SARSA(\lambda) is implemented on both a simulated and real robot that must learn a specific rewarding sequence of elementary behaviors from exploration. Results show DN-SARSA(\lambda) performs on the level of the discrete SARSA(\lambda), validating the feasibility of general reinforcement learning without compromising neural dynamics.Comment: Sohrob Kazerounian, Matthew Luciw are Joint first author

Towards More Expressive and Usable Types for Dynamic Languages

Many popular programming languages, including Ruby, JavaScript, and Python, feature dynamic type systems, in which types are not known until runtime. Dynamic typing provides the programmer with flexibility and allows for rapid program development. In contrast, static type systems, found in languages like C++ and Java, help catch errors early during development, enforce invariants as programs evolve, and provide useful documentation via type annotations. Many researchers have explored combining these contrasting paradigms, seeking to marry the flexibility of dynamic types with the correctness guarantees and documentation of static types. However, many challenges remain in this pursuit: programmers using dynamic languages may wish to verify more expressive properties than basic type safety; operations for commonly used libraries, such as those for databases and heterogeneous data structures, are difficult to precisely type check; and type inference---the process of automatically deducingthe types of methods and variables in a program---often produces type annotations that are complex and verbose, and thus less usable for the programmer. To address these issues, I present four pieces of work that aim to increase the expressiveness and usability of static types for dynamic languages. First, I present RTR, a system that adds refinement types to Ruby: basic types extended with expressive predicates. RTR uses assume-guarantee reasoning and a novel idea called just-in-time verification---in which verification is deferred until runtime---to handle dynamic program features such as mixins and metaprogramming. We found RTR was useful for verifying key methods in six Ruby programs. Second, I present CompRDL, a Ruby type system that allows library method type signatures to include type-level computations(or comp types). Comp types can be used to precisely type check database queries, as well as operations over heterogeneous data structures like arrays and hashes. We used CompRDL to type check methods from six Ruby programs, enabling us to check more expressive properties, with fewer manually inserted type casts, than was possible without comp types. Third, I present InferDL, a Ruby type inference system that aims to produce usable type annotations. Becausethe types inferred by standard, constraint-based inference are often complex and less useful to the programmer, InferDL complements constraints with configurable heuristics that aim to produce more usable types. We applied InferDL to four Ruby programs with existing type annotations and found that InferDL inferred 22% more types that matched the prior annotations compared to standard inference. Finally, I present SimTyper, a system that builds on InferDL by using a novel machine learning-based technique called type equality prediction. When standard and heuristic inference produce a non-usable type for a position (argument/return/variable), we use a deep similarity network to compare that position to other positions with usable types. If the network predicts that two positions have the same type, we guess the usable type in place of the non-usable one, and check the guess against constraints to ensure soundness. We evaluated SimTyper on eight Ruby programs with prior annotations and found that, compared to standard inference, SimTyper finds 69% more types that match programmer-written annotations. In sum, I claim that RTR, CompRDL, InferDL, and SimTyper represent promising steps towards more expressive and usable types for dynamic languages

Guided Tuning of Turbine Blades: A Practical Method to Avoid Operating at Resonance

In gas turbine applications, forced vibrations of turbine blades under resonant-or nearly resonant-conditions are undesirable. Usually in airfoil design procedures, at least the first three blade modes are required to be free of excitation in the operating speed range. However, not uncommonly, a blade may experience resonance at other higher natural frequencies. In an attempt to avoid resonant oscillations, the structural frequencies are tuned away from the excitation frequencies by changing the geometry of the blade. The typical iterative design process-of adding and removing material through restacking the airfoil sections-is laborious and in no way assures an optimal design. In response to the need for an effective and fast methodology, the guided tuning of turbine blades method (GTTB) is developed and presented in this paper. A practical tuning technique, the GTTB method is based on structural perturbations to the mass and stiffness at critical locations, as determined by the methodology described herein. This shifts the excited natural frequency out of the operating speed range, while leaving the other structural frequencies largely undisturbed. The methodology is demonstrated here in the redesign of an actual turbine blade. The numerical results are experimentally validated using a laser vibrometer. The results indicate that the proposed method is not computationally intensive and renders effective results that jibe with experiments

Cardiac troponin I assessment and late cardiac complications after carotid stenting or endarterectomy

PurposeWhen compared with carotid endarterectomy (CEA), percutaneous carotid angioplasty with stent replacement (CAS) is a less invasive technique in the treatment of carotid stenosis. However, periprocedural hemodynamic instability still remains a challenge. This instability might lead to myocardial damage, which is now measured accurately by using cardiac troponin I (CTnI).MethodsThis study was designed to compare the periprocedural variation of CTnI in 150 consecutive patients scheduled to undergo CEA (n = 75) or CAS (n = 75). The levels of CTnI were measured until the third postoperative day in all patients. Short-term (1 month) and long-term (up to 5 years) postoperative cardiac outcome were assessed by means of chart review, regular follow-ups, and telephone calls.ResultsThere was not any statistically significant difference between the 2 groups regarding the demographic characteristics and preprocedural medical status. The incidence of increase of CTnI (>0.5 ng/mL) was significantly higher in the CEA group (13%) compared with that in the CAS group (1%; P = .001). During the acute postprocedural period, the CAS group was significantly more prone to hypotension, requiring vasopressor therapy, whereas the CEA group had more hypertension, necessitating hypotensive medications (P < .001). At 5 years, the overall incidence of major cardiac complications (nonfatal myocardial infarction and death related to cardiac origin) was significantly more frequent in the CEA group (20% vs 5%, P < .01).ConclusionThe results of our study suggest that CAS yielded less myocardial damage in the short and long term when compared with CEA. Larger randomized multicenter trials with long-term outcomes are necessary to confirm our findings

Broadening Participation: A Report on a Series of Workshops Aimed at Building Community and Increasing the Number of Women and Minorities in Engineering Design

Despite some progress in increasing the numbers of women and minorities in engineering over the past 30 years, their full participation in the discipline has yet to be achieved, particularly in engineering academia. One cause is the leaky pipeline ; even after women and minorities choose to major in engineering, they drop out at rates higher than their counterparts along all career stages (undergraduate school, graduate school, tenure-track, etc.). Their small numbers creates isolation that has the unfortunate risks of struggle, less professional success, less sense of personal belonging, and less retention. Our hypothesis is that building a community that provides networking and support, opportunities for collaboration, and professional development, will lead to greater career success, personal fulfillment and professional happiness, retention, and greater participation/contribution from women and minorities. The authors have been conducting a series of workshops aimed at broadening participation of women and other minorities within the American Society of Mechanical Engineers (ASME) Design Engineering Division (DED). This paper reports on the activities and results of the workshop series. Pre-workshop survey data indicated a clear opportunity to address the unmet needs of underrepresented groups in the ASME DED. Post-workshop survey data showed success in attendee satisfaction with feelings of inclusion and community, professional skill building, and the prospect of future workshops held by the committee. A follow-up impact assessment survey showed that the workshops have led to greater participation in DED activities, new positive connections within the DED community, and positive feelings regarding their communication/collaboration abilities, self confidence, level of comfort, feelings of inclusion, professional goals, leadership abilities, and skill sets. While these results are encouraging, the committee feels strongly that greater success in broadening the participation of underrepresented groups in engineering would be possible by sharing our strategies and successes, and learning from others with similar experience creating communities within the many engineering disciplines represented in ASEE

Uptake of oxLDL and IL-10 production by macrophages requires PAFR and CD36 recruitment into the same lipid rafts

Macrophage interaction with oxidized low-density lipoprotein (oxLDL) leads to its differentiation into foam cells and cytokine production, contributing to atherosclerosis development. In a previous study, we showed that CD36 and the receptor for platelet-activating factor (PAFR) are required for oxLDL to activate gene transcription for cytokines and CD36. Here, we investigated the localization and physical interaction of CD36 and PAFR in macrophages stimulated with oxLDL. We found that blocking CD36 or PAFR decreases oxLDL uptake and IL-10 production. OxLDL induces IL-10 mRNA expression only in HEK293T expressing both receptors (PAFR and CD36). OxLDL does not induce IL-12 production. The lipid rafts disruption by treatment with βCD reduces the oxLDL uptake and IL-10 production. OxLDL induces co-immunoprecipitation of PAFR and CD36 with the constitutive raft protein flotillin-1, and colocalization with the lipid raft-marker GM1-ganglioside. Finally, we found colocalization of PAFR and CD36 in macrophages from human atherosclerotic plaques. Our results show that oxLDL induces the recruitment of PAFR and CD36 into the same lipid rafts, which is important for oxLDL uptake and IL-10 production. This study provided new insights into how oxLDL interact with macrophages and contributing to atherosclerosis development

Planar and Spherical Rigid Motion as Special Cases of Spherical and 3-Spherical Motion

This paper describes the operational theory and design of a quadri-directional air thruste

RhoB controls coordination of adult angiogenesis and lymphangiogenesis following injury by regulating VEZF1-mediated transcription

Mechanisms governing the distinct temporal dynamics that characterize post-natal angiogenesis and lymphangiogenesis elicited by cutaneous wounds and inflammation remain unclear. RhoB, a stress-induced small GTPase, modulates cellular responses to growth factors, genotoxic stress and neoplastic transformation. Here we show, using RhoB null mice, that loss of RhoB decreases pathological angiogenesis in the ischaemic retina and reduces angiogenesis in response to cutaneous wounding, but enhances lymphangiogenesis following both dermal wounding and inflammatory challenge. We link these unique and opposing roles of RhoB in blood versus lymphatic vasculatures to the RhoB-mediated differential regulation of sprouting and proliferation in primary human blood versus lymphatic endothelial cells. We demonstrate that nuclear RhoB-GTP controls expression of distinct gene sets in each endothelial lineage by regulating VEZF1-mediated transcription. Finally, we identify a small-molecule inhibitor of VEZF1–DNA interaction that recapitulates RhoB loss in ischaemic retinopathy. Our findings establish the first intra-endothelial molecular pathway governing the phased response of angiogenesis and lymphangiogenesis following injury