Radiative transfer in the mesosphere

Radiative temperature changes for molecular gases under non local thermodynamic equilibriu

Shapes of Semiflexible Polymer Rings

The shape of semiflexible polymer rings is studied over their whole range of flexibility. Investigating the joint distribution of asphericity and nature of asphericity as well as their respective averages we find two distinct shape regimes depending on the flexibility of the polymer. For small perimeter to persistence length the fluctuating rings exhibit only planar, elliptical configurations. At higher flexibilities three dimensional, crumpled structures arise. Analytic calculations for tight polymer rings confirm an elliptical shape in the stiff regime.Comment: 4 pages, 3 figures, Version as published in Phys. Rev. Let

Oregon's nutria problem

The nutria or coypu, Myocastor coypus, is a large semi-aquatic rodent that superficially resembles an overgrown muskrat or a stunted beaver. They were introduced into Oregon from about 1930 to the 1950's. At one time Oregon had more than 600 fur farmers raising these animals for fur; now there are none. Some animals escaped and many others were released into the wild when it became apparent that pelt values were nonexistent and production costs greatly exceeded profits. Being prolific and quite mobile, the nutria quickly spread through much of western Oregon. By the 1960's damage to agricultural crops was common to severe in western Oregon. Crops damaged included seed, grain, forage, hay and trees. Burrowing damage to stream banks, field borders, and farm ponds was reported in many areas. Growth and reproduction data for Oregon nutria are included. Methods for controlling feral nutria including the use of prolin, red squill, strychnine alkaloid, and zinc phosphide are reported. Fur trapping and adverse weather as factors in population reduction are discussed

K-Adaptability in Two-Stage Distributionally Robust Binary Programming

We propose to approximate two-stage distributionally robust programs with binary recourse decisions by their associated K-adaptability problems, which pre-select K candidate secondstage policies here-and-now and implement the best of these policies once the uncertain parameters have been observed. We analyze the approximation quality and the computational complexity of the K-adaptability problem, and we derive explicit mixed-integer linear programming reformulations. We also provide efficient procedures for bounding the probabilities with which each of the K second-stage policies is selected

Understanding the truth about subjectivity

Results of two experiments show children’s understanding of diversity in personal preference is incomplete. Despite acknowledging diversity, in Experiment 1(N=108), 6- and 8-year-old children were less likely than adults to see preference as a legitimate basis for personal tastes and more likely to say a single truth could be found about a matter of taste. In Experiment 2 (N=96), 7- and 9-year-olds were less likely than 11- and 13-yearolds to say a dispute about a matter of preference might not be resolved. These data suggest that acceptance of the possibility of diversity does not indicate an adult-like understanding of subjectivity. An understanding of the relative emphasis placed on objective and subjective factors in different contexts continues to develop into adolescence

A distributionally robust perspective on uncertainty quantification and chance constrained programming

The objective of uncertainty quantification is to certify that a given physical, engineering or economic system satisfies multiple safety conditions with high probability. A more ambitious goal is to actively influence the system so as to guarantee and maintain its safety, a scenario which can be modeled through a chance constrained program. In this paper we assume that the parameters of the system are governed by an ambiguous distribution that is only known to belong to an ambiguity set characterized through generalized moment bounds and structural properties such as symmetry, unimodality or independence patterns. We delineate the watershed between tractability and intractability in ambiguity-averse uncertainty quantification and chance constrained programming. Using tools from distributionally robust optimization, we derive explicit conic reformulations for tractable problem classes and suggest efficiently computable conservative approximations for intractable ones

SQPR: Stream Query Planning with Reuse

When users submit new queries to a distributed stream processing system (DSPS), a query planner must allocate physical resources, such as CPU cores, memory and network bandwidth, from a set of hosts to queries. Allocation decisions must provide the correct mix of resources required by queries, while achieving an efficient overall allocation to scale in the number of admitted queries. By exploiting overlap between queries and reusing partial results, a query planner can conserve resources but has to carry out more complex planning decisions. In this paper, we describe SQPR, a query planner that targets DSPSs in data centre environments with heterogeneous resources. SQPR models query admission, allocation and reuse as a single constrained optimisation problem and solves an approximate version to achieve scalability. It prevents individual resources from becoming bottlenecks by re-planning past allocation decisions and supports different allocation objectives. As our experimental evaluation in comparison with a state-of-the-art planner shows SQPR makes efficient resource allocation decisions, even with a high utilisation of resources, with acceptable overheads

Upper extremity pain and overuse injuries in fly-fishing: A North American cross-sectional survey and implications for injury prevention

Background: Fly-fishing requires rhythmic, coordinated movements to successfully cast a fly line. Previous studies have shown that the biomechanical demands of fly-casting may cause some individuals to develop upper extremity pain or injuries. Purpose: To report the rates, trends, and contributing factors of upper extremity pain and overuse injuries in a sample of North American recreational fly-fishers. Study Design: Descriptive epidemiology study. Methods: Participants were reached via 3 popular online fly-fishing forums in April 2019. Each consenting North American participant over 18 years of age was given a link to a unique survey that recorded his or her demographic and orthopaedic histories, fly-fishing experience, equipment, casting techniques, upper extremity pain after fly-fishing, and chronic outcomes. Results: The 162 fly-fishers included were 63.3 (± 11.5) years of age, and 95.1% were men. In total, 59 (36.4%) reported experiencing upper extremity pain immediately after fly-fishing. Pain was rated a 4.0 (interquartile range, 3.0-6.0) on a 10-point Likert scale, commonly lasting less than 1 day (45.0%) or between 1 day and 1 week (45.0%). The majority (62.7%) reported not needing to see a medical provider for their pain/soreness. Those who did most commonly received diagnoses of elbow or rotator cuff tendinitis. Pain/soreness was associated with casting in an elliptical/sidearm fashion, compared with overhead or 2-handed casting ( Conclusion: In this sample of recreational fly-fishers, no aspects of fly-fishing were associated with long-term upper extremity disability, and only a little more than a third reported having transient pain immediately after fishing. Casting style, using weighted lines or added weight, and grip style were all associated with pain. These are modifiable risk factors that can be adjusted to reduce the risk of upper extremity pain immediately after fly-fishing

The Skylab concentrated atmospheric radiation project

The author has identified the following significant results. Comparison of several existing infrared radiative transfer models under somewhat controlled conditions and with atmospheric observations of Skylab's S191 and S192 radiometers illustrated that the models tend to over-compute atmospheric attenuation in the window region of the atmospheric infrared spectra