Algebraic-Combinatorial Methods for Low-Rank Matrix Completion with Application to Athletic Performance Prediction

This paper presents novel algorithms which exploit the intrinsic algebraic and combinatorial structure of the matrix completion task for estimating missing en- tries in the general low rank setting. For positive data, we achieve results out- performing the state of the art nuclear norm, both in accuracy and computational efficiency, in simulations and in the task of predicting athletic performance from partially observed data

Rigidity percolation by next-nearest-neighbor bonds on generic and regular isostatic lattices

Theoretical Physic

Chamber-based insights into the factors controlling epoxydiol (IEPOX) secondary organic aerosol (SOA) yield, composition, and volatility

We present measurements utilizing the Filter Inlet for Gases and Aerosols (FIGAERO) applied to chamber measurements of isoprene-derived epoxydiol (IEPOX) reactive uptake to aqueous acidic particles and associated secondary organic aerosol (SOA) formation. Similar to recent field observations with the same instrument, we detect two molecular components desorbing from the IEPOX SOA in high abundance: C5H12O4 and C5H10O3. The thermal desorption signal of the former, presumably 2-methyltetrols, exhibits two distinct maxima, suggesting it arises from at least two different SOA components with significantly different effective volatilities. Isothermal evaporation experiments illustrate that the most abundant component giving rise to C5H12O4 is semi-volatile, undergoing nearly complete evaporation within 1 h while the second, less volatile component remains unperturbed and even increases in abundance. We thus confirm, using controlled laboratory studies, recent analyses of ambient SOA measurements showing that IEPOX SOA is of very low volatility and commonly measured IEPOX SOA tracers such as C5H12O4 and C5H10O3, presumably 2-methyltetrols and C5-alkene triols or 3-MeTHF-3,4-diols, result predominantly from thermal decomposition in the FIGAERO-CIMS. We infer that other measurement techniques using thermal desorption or prolonged heating for analysis of SOA components may also lead to reported 2-methyltetrols and C5-alkene triols or 3-MeTHF-3,4-diol structures. We further show that IEPOX SOA volatility continues to evolve via acidity-enhanced accretion chemistry on the timescale of hours, potentially involving both 2-methyltetrols and organosulfates.Peer reviewe

Integrating Positive and Clinical Psychology: Viewing Human Functioning as Continua from Positive to Negative Can Benefit Clinical Assessment, Interventions and Understandings of Resilience

In this review we argue in favour of further integration between the disciplines of positive and clinical psychology. We argue that most of the constructs studied by both positive and clinical psychology exist on continua ranging from positive to negative (e.g., gratitude to ingratitude, anxiety to calmness) and so it is meaningless to speak of one or other field studying the “positive” or the “negative”. However, we highlight historical and cultural factors which have led positive and clinical psychologies to focus on different constructs; thus the difference between the fields is more due to the constructs of study rather than their being inherently “positive” or “negative”. We argue that there is much benefit to clinical psychology of considering positive psychology constructs because; (a) constructs studied by positive psychology researchers can independently predict wellbeing when accounting for traditional clinical factors, both cross-sectionally and prospectively, (2) the constructs studied by positive psychologists can interact with risk factors to predict outcomes, thereby conferring resilience, (3) interventions that aim to increase movement towards the positive pole of well-being can be used encourage movement away from the negative pole, either in isolation or alongside traditional clinical interventions, and (4) research from positive psychology can support clinical psychology as it seeks to adapt therapies developed in Western nations to other cultures

Rigidity of 1-coordinated frameworks in 2 dimensions:16th Cologne-Twente Workshop on Graphs and Combinatorial Optimization, CTW 2018 - Proceedings of the Workshop

A bar-joint framework (G, p) is a graph G with an embedding of its vertices into R d. Coordinated frameworks are those with a subset of bars that may extend or retract, but must all do so at the same time, in contrast to standard frameworks in which the bar lengths are fixed by the embedding p. We wish to extend characterisations of standard frameworks to the coordinated context

Initial international multicenter human experience with a novel epicardial access needle embedded with a real-time pressure/frequency monitoring to facilitate epicardial access : feasibility and safety

Background Epicardial ablation is often necessary for the treatment of complex arrhythmias refractory to endocardial ablation. Conventional needle access to the pericardial space is considered quite challenging, and it is often associated with several potential complications, particularly inadvertent right ventricular puncture. The novel EpiAccess needle tip is embedded with a pressure sensor able to report the pressure waveform in real time when used with the EpiAccess System. Objective We prospectively evaluated the feasibility and safety of the EpiAccess System by EpiEP, Inc., with a novel epicardial access needle in a multicenter study. Methods Twenty-five patients with a clinical need for epicardial access were enrolled. The EpiAccess needle and EpiAccess System were used for epicardial access in each case. Successful epicardial access, defined as the ability to introduce a guidewire into the epicardial space, was assessed via the device and confirmed with fluoroscopy. Significant pericardial bleeding was defined as >80 mL of blood by using peer review article definitions. Results Patients were men (76%) with a mean age of 62 years (range 28-84 years). Epicardial access for ventricular tachycardia ablation was indicated in 80% of the patients. Successful epicardial access was obtained in all cases, with pressure monitoring guiding pericardial wire access in all cases. One delayed pericardial effusion occurred. Conclusion Epicardial access with the novel EpiAccess needle and System with real-time pressure monitoring is feasible and safe. The pressure monitoring capability identifies successfully the epicardial space, facilitating access and potentially minimizing complications. This has relevant clinical implications

Nitrogen, Aerosol Composition, and Halogens on a Tall Tower (NACHTT): Overview of a wintertime air chemistry field study in the front range urban corridor of Colorado

The Nitrogen, Aerosol Composition, and Halogens on a Tall Tower (NACHTT) field experiment took place during late winter, 2011, at a site 33 km north of Denver, Colorado. The study included fixed-height measurements of aerosols, soluble trace gases, and volatile organic compounds near surface level, as well as vertically resolved measurements of nitrogen oxides, aerosol composition, soluble gas-phase acids, and halogen species from 3 to 270 m above ground level. There were 1928 individual profiles during the three-week campaign to characterize trace gas and aerosol distributions in the lower levels of the boundary layer. Nitrate and ammonium dominated the ionic composition of aerosols and originated primarily from local or regional sources. Sulfate and organic matter were also significant and were associated primarily with longer-range transport to the region. Aerosol chloride was associated primarily with supermicron size fractions and was always present in excess of gas-phase chlorine compounds. The nighttime radical reservoirs, nitryl chloride, ClNO2, and nitrous acid, HONO, were both consistently present in nighttime urban air. Nitryl chloride was especially pronounced in plumes from large point sources sampled aloft at night. Nitrous acid was typically most concentrated near the ground surface and was the dominant contributor (80%) to diurnally averaged primary OH radical production in near-surface air. Large observed mixing ratios of light alkanes, both in near-surface air and aloft, were attributable to local emissions from oil and gas activities