Message-Layer Encryption in Ricochet

My intention for this project was to implement encryption and authentication on Ricochet\u27s message layer. This provides two major benefits. The first is a higher level of encryption in the event that a flaw is found in the existing channel-layer encryption, or if increases in computing power make attacks on that encryption feasible. Tor is used by the military, journalists, law enforcement, researchers, and activists, whose communications may be interesting to state-level adversaries and criminal organizations with access to great amount of computing resources. Additionally, message-layer encryption would allow users to specify relay nodes that can temporarily store messages and forward them once the recipient comes online. Because the channel-layer encryption in hidden services only encrypts data between end users, the addition of authentication and encryption within messages would enable the application to conceal communication data from relay nodes

Synthesis And Characterization Of (pyNO−)2GaCl: A Redox-Active Gallium Complex

We report the synthesis of a gallium complex incorporating redox-active pyridyl nitroxide ligands. The (pyNO−)2GaCl complex was prepared in 85% yield via a salt metathesis route and was characterized by 1H and 13C NMR spectroscopies, X-ray diffraction, and theory. UV–Vis absorption spectroscopy and electrochemistry were used to access the optical and electrochemical properties of the complex, respectively. Our discussion focuses primarily on a comparison of the gallium complex to the corresponding aluminum derivative and shows that although the complexes are very similar, small differences in the electronic structure of the complexes can be correlated to the identity of the metal

An Inquiry into the Practice of Proving in Low-Dimensional Topology

The aim of this article is to investigate specific aspects connected with visualization in the practice of a mathematical subfield: low-dimensional topology. Through a case study, it will be established that visualization can play an epistemic role. The background assumption is that the consideration of the actual practice of mathematics is relevant to address epistemological issues. It will be shown that in low-dimensional topology, justifications can be based on sequences of pictures. Three theses will be defended. First, the representations used in the practice are an integral part of the mathematical reasoning. As a matter of fact, they convey in a material form the relevant transitions and thus allow experts to draw inferential connections. Second, in low-dimensional topology experts exploit a particular type of manipulative imagination which is connected to intuition of two- and three-dimensional space and motor agency. This imagination allows recognizing the transformations which connect different pictures in an argument. Third, the epistemic—and inferential—actions performed are permissible only within a specific practice: this form of reasoning is subject-matter dependent. Local criteria of validity are established to assure the soundness of representationally heterogeneous arguments in low-dimensional topology

Flights in my hands : coherence concerns in designing Strip'TIC, a tangible space for air traffic controllers

Best Paper Honorable Mention awardInternational audienceWe reflect upon the design of a paper-based tangible interactive space to support air traffic control. We have observed, studied, prototyped and discussed with controllers a new mixed interaction system based on Anoto, video projection, and tracking. Starting from the understanding of the benefits of tangible paper strips, our goal is to study how mixed physical and virtual augmented data can support the controllers' mental work. The context of the activity led us to depart from models that are proposed in tangible interfaces research where coherence is based on how physical objects are representative of virtual objects. We propose a new account of coherence in a mixed interaction system that integrates externalization mechanisms. We found that physical objects play two roles: they act both as representation of mental objects and as tangible artifacts for interacting with augmented features. We observed that virtual objects represent physical ones, and not the reverse, and, being virtual representations of physical objects, should seamlessly converge with the cognitive role of the physical object. Finally, we show how coherence is achieved by providing a seamless interactive space

Why 'scaffolding' is the wrong metaphor : the cognitive usefulness of mathematical representations.

The metaphor of scaffolding has become current in discussions of the cognitive help we get from artefacts, environmental affordances and each other. Consideration of mathematical tools and representations indicates that in these cases at least (and plausibly for others), scaffolding is the wrong picture, because scaffolding in good order is immobile, temporary and crude. Mathematical representations can be manipulated, are not temporary structures to aid development, and are refined. Reflection on examples from elementary algebra indicates that Menary is on the right track with his ‘enculturation’ view of mathematical cognition. Moreover, these examples allow us to elaborate his remarks on the uniqueness of mathematical representations and their role in the emergence of new thoughts.Peer reviewe

Perioperative management of the patient undergoing automatic internal cardioverter-defibrillator implantation

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/28646/1/0000461.pd

Lack of trust in maternal support is associated with negative interpretations of ambiguous maternal behavior

Attachment theory assumes that children who lack trust in maternal availability for support are more inclined to interpret maternal behavior in congruence with their expectation that mother will remain unavailable for support. To provide the first test of this assumption, early adolescents (9-13 years old) were asked to assess whether ambiguous interactions with mother should be interpreted in a positive or a negative way. In our sample (n = 322), results showed that early adolescents' lack of trust in their mother's availability for support was related to more negative interpretations of maternal behavior. The associations remained significant after controlling for depressive mood. The importance of these findings for our understanding of attachment theory, attachment stability, and clinical practice are discussed

Evaluation of left ventricular ejection fraction as a measure of pump performance in patients with chronic mitral regurgitation

Left ventricular (LV) ejection fraction may not adequately detect a reduction in LV systolic performance resulting from chronic mitral regurgitation (MR), due to ventricular unloading into the low-impedance left atrium. To determine whether LV ejection fraction sufficiently gauges myocardial function in MR, nine patients were studied using micromanometer-measured LV pressures and biplane cineventriculography before and 1 year after mitral valve surgery. Six control patients were also studied. LV ejection fraction was normal in MR patients, despite an increase in LV end-systolic volume index. LV end-systolic pressure-volume and stress-volume ratios in MR patients were lower than in controls ( P < 0.05 and P < 0.01), suggesting that LV systolic performance fell. One year after mitral valve surgery, LV ejection fraction decreased ( P < 0.05) even though LV end-systolic volume index ( P < 0.05), pressure-volume ( P < 0.05), and stress-volume ratios ( P < 0.01) all improved. Thus, LV ejection fraction inadequately reflected LV systolic function in MR patients before and after mitral valve surgery. Cathet. Cardiovasc. Intervent. 49:290–296, 2000. © 2000 Wiley-Liss, Inc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/35248/1/14_ftp.pd

Insight out : making creativity visible

Models of creative problem solving are predicated upon mental states to explain everything from the outcome of problem‐solving experiments to the emergence of artistic creativity. We present two converging perspectives that describe a profoundly different ontological description of creativity. Our analysis proceeds from a distinction between first‐order problem solving, where the agent interacts with a physical model of the problem and second‐order problem solving, where the agent must cogitate a solution to a problem that is presented as a verbal description of a state of the world but where the agent does not or cannot transform physical elements of a problem. We acknowledge the recent evidence that foregrounds the importance of working memory in problem solving, including insight problem solving. However, we stress that the impressive psychometric success is obtained with a methodology that only measures second‐order problem solving; we question whether first‐order problem solving is equally well predicted by measures of cognitive or dispositional capacities. We propose that if mental simulation is replaced by the opportunity to engage with a physical model of a problem then the environment can provide affordances that help the participant to solve problems. In the second part of the paper, we present the subjective experience of an artist as he monitors the microdecisions that occur during the morphogenesis of a large, clay, sculptural installation. The testimony is a vivid demonstration that creative action occurs, not in the brain, but in the movement between the hand and the clay. Insight becomes outsight

Diagnostic Algorithm for Joint Pain in Patients with Inflammatory Bowel Disorders

Aim. An algorithm development for joint pain differential diagnosis in patients with inflammatory bowel disorders (IBD) and its validation in clinical practice.Materials and methods. A total of 349 IBD patients hospitalised for gastroenterological complaints at the Chelyabinsk Regional Clinical Hospital during 2017–2020 have been examined.Results. Upon survey, 97 (27.8%) IBD patients complained of joint pain. Ulcerative colitis (UC) predominated (79 patients; 81.4%), Crohn’s disease (CD) had a 18.6% incidence. In survey, 27% UC and 32.1% CD patients reported joint pain (p = 0.26). Among IBD patients, 52.6% had mechanical, and 47.4% — inflammatory pain. The inflammatory back pain (IBP) rate in survey cohort was 23.7%. Use of a diagnostic algorithm allowed concomitant rheumatic disease detection in 7 (7.2%) patients from the IBD–joint pain cohort: 2 patients were diagnosed with psoriatic spondyloarthritis, 2 — rheumatoid arthritis, 1 — gout and 2 — with ankylosing spondylitis. IBD-associated arthritis was diagnosed in 41 (42.3%) cases, osteoarthritis — in 38 (39.2%) IBD patients with joint pain, arthralgia with no objective inflammation, impaired joint function or lesions in X-ray and/or ultrasound — in 13 (13.4%) patients.Conclusion. Joint pain complaints are common in IBD patients and require a multispecialty rheumatologists-involving approach to proceed with differential diagnosis and opting for treatment tactics. A clinically verified algorithm coupled with laboratory tests and instrumental imaging facilitates diagnosis and optimal therapy selection in IBD patients with complaints of joint pain