REGIONAL AND SECTORAL EFFECTS OF COMPETITION FOR WHEAT TRANSPORTATION

Crop Production/Industries,

Ewald Sums for One Dimension

We derive analytic solutions for the potential and field in a one-dimensional system of masses or charges with periodic boundary conditions, in other words Ewald sums for one dimension. We also provide a set of tools for exploring the system evolution and show that it's possible to construct an efficient algorithm for carrying out simulations. In the cosmological setting we show that two approaches for satisfying periodic boundary conditions, one overly specified and the other completely general, provide a nearly identical clustering evolution until the number of clusters becomes small, at which time the influence of any size-dependent boundary cannot be ignored. Finally we compare the results with other recent work with the hope of providing clarification over differences these issues have induced. We explain that modern formulations of physics require a well defined potential which is not available if the forces are screened directly.Comment: 2 figures added references expanded discussion of algorithm corrected figures added discussion of screened forc

Predictors and outcomes of crossover to surgery from physical therapy for meniscal tear and osteoarthritis a randomized trial comparing physical therapy and surgery

BACKGROUND: Arthroscopic partial meniscectomy (APM) combined with physical therapy (PT) have yielded pain relief similar to that provided by PT alone in randomized trials of subjects with a degenerative meniscal tear. However, many patients randomized to PT received APM before assessment of the primary outcome. We sought to identify factors associated with crossing over to APM and to compare pain relief between patients who had crossed over to APM and those who had been randomized to APM. METHODS: We used data from the MeTeOR (Meniscal Tear in Osteoarthritis Research) Trial of APM with PT versus PT alone in subjects ≥45 years old who had mild-to-moderate osteoarthritis and a degenerative meniscal tear. We assessed independent predictors of crossover to APM among those randomized to PT. We also compared pain relief at 6 months among those randomized to PT who crossed over to APM, those who did not cross over, and those originally randomized to APM. RESULTS: One hundred and sixty-four subjects were randomized to and received APM and 177 were randomized to PT, of whom 48 (27%) crossed over to receive APM in the first 140 days after randomization. In multivariate analyses, factors associated with a higher likelihood of crossing over to APM among those who had originally been randomized to PT included a baseline Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) Pain Score of ≥40 (risk ratio [RR] = 1.99; 95% confidence interval [CI] = 1.00, 3.93) and symptom duration of <1 year (RR = 1.74; 95% CI = 0.98, 3.08). Eighty-one percent of subjects who crossed over to APM and 82% of those randomized to APM had an improvement of ≥10 points in their pain score at 6 months, as did 73% of those who were randomized to and received only PT. CONCLUSIONS: Subjects who crossed over to APM had presented with a shorter symptom duration and greater baseline pain than those who did not cross over from PT. Subjects who crossed over had rates of surgical success similar to those of the patients who had been randomized to surgery. Our findings also suggest that an initial course of rigorous PT prior to APM may not compromise surgical outcome. LEVEL OF EVIDENCE: Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence

Electrostatic Solar Sail: A Propellantless Propulsion Concept for an Interstellar Probe Mission

The propulsion of an electrostatic solar sail (E Sail) is obtained by extracting momentum from the solar wind through electrostatic repulsion of the positively charged solar wind ions (see Figure 1). The positively charged solar wind protons are deflected by the electric field created around the tethers.This electric field grows in diameter as the spacecraft moves away from the Sun, therefore the E Sail effective area grows. The growth of the E-Sail effective area allows the propulsive force to decrease as 1/r up to distances of 20 AU as it moves away from the Sun, unlike solar sail propulsion whose thrust decreases as 1/r 2 but only to distances of 5AU. This propulsive force is created without using propellant and, therefore, E-sail avoids both the mass and complexity of chemical rockets (that require large amounts of propellant, propellant storage tanks, plumbing, valves, and insulation)

All-optical sub-Kelvin sympathetic cooling of a levitated microsphere in vacuum

Funding: UK Engineering and Physical Sciences Research Council (EP/P030017/1).We demonstrate all-optical sympathetic cooling of a laser-trapped microsphere to sub-Kelvin temperatures, mediated by optical binding to a feedback-cooled adjacent particle. Our study opens prospects for multi-particle quantum entanglement and sensing in levitated optomechanics.Publisher PDFPeer reviewe

Conformational Dynamics of hSGLT1 during Na+/Glucose Cotransport

This study examines the conformations of the Na+/glucose cotransporter (SGLT1) during sugar transport using charge and fluorescence measurements on the human SGLT1 mutant G507C expressed in Xenopus oocytes. The mutant exhibited similar steady-state and presteady-state kinetics as wild-type SGLT1, and labeling of Cys507 by tetramethylrhodamine-6-maleimide had no effect on kinetics. Our strategy was to record changes in charge and fluorescence in response to rapid jumps in membrane potential in the presence and absence of sugar or the competitive inhibitor phlorizin. In Na+ buffer, step jumps in membrane voltage elicited presteady-state currents (charge movements) that decay to the steady state with time constants τmed (3–20 ms, medium) and τslow (15–70 ms, slow). Concurrently, SGLT1 rhodamine fluorescence intensity increased with depolarizing and decreased with hyperpolarizing voltages (ΔF). The charge vs. voltage (Q-V) and fluorescence vs. voltage (ΔF-V) relations (for medium and slow components) obeyed Boltzmann relations with similar parameters: zδ (apparent valence of voltage sensor) ≈ 1; and V0.5 (midpoint voltage) between −15 and −40 mV. Sugar induced an inward current (Na+/glucose cotransport), and reduced maximal charge (Qmax) and fluorescence (ΔFmax) with half-maximal concentrations (K0.5) of 1 mM. Increasing [αMDG]o also shifted the V0.5 for Q and ΔF to more positive values, with K0.5's ≈ 1 mM. The major difference between Q and ΔF was that at saturating [αMDG]o, the presteady-state current (and Qmax) was totally abolished, whereas ΔFmax was only reduced 50%. Phlorizin reduced both Qmax and ΔFmax (Ki ≈ 0.4 μM), with no changes in V0.5's or relaxation time constants. Simulations using an eight-state kinetic model indicate that external sugar increases the occupancy probability of inward-facing conformations at the expense of outward-facing conformations. The simulations predict, and we have observed experimentally, that presteady-state currents are blocked by saturating sugar, but not the changes in fluorescence. Thus we have isolated an electroneutral conformational change that has not been previously described. This rate-limiting step at maximal inward Na+/sugar cotransport (saturating voltage and external Na+ and sugar concentrations) is the slow release of Na+ from the internal surface of SGLT1. The high affinity blocker phlorizin locks the cotransporter in an inactive conformation

Updated checklist of the mosquitoes of Oklahoma including new state records and West Nile virus vectors, 2003-06

The mosquito fauna of Oklahoma has not been evaluated since 1965 and no report has been published concerning species associated with urban areas in the state. Mosquito collections were conducted as part of the West Nile virus (WNV) surveillance program between April and November from 2003 to 2006, using standard collection methods. A total of 74,756 adults were collected in 26 urban centers in 16 counties of Oklahoma. Altogether, 40 species were recorded during this study period, bringing the total mosquito species recorded in Oklahoma to 62 species in 9 different genera and 18 subgenera. An updated checklist of Oklahoma mosquito fauna is included with a comparison to historical records. New state records include 3 species: Aedes muelleri, Anopheles perplexens, and Culex coronator. In addition to updating the checklist, 12 species of mosquitoes were tested for WNV. Pools of Culex pipiens complex represented the highest proportion testing positive for WNV (134/766, 17.5%), followed by Cx. tarsalis (13/192, 6.8%) and Aedes albopictus (5/215, 2.3%). West Nile virus-positive mosquitoes were detected earliest in June 2005 and latest in November 2004. Infected Cx. pipiens complex testing positive for WNV were more prevalent in the eastern and central areas of Oklahoma, whereas positive Cx. tarsalis were found mainly in the western areas of the state. This distinct geographical difference needs to be monitored and followed up to ensure optimal mosquito control efforts in Oklahoma communities with mosquito control capabilities.Peer reviewedEntomology and Plant Patholog

Updated distribution of Aedes albopictus in Oklahoma, and implications in arbovirus transmission

A series of statewide surveys were conducted in Oklahoma in the summers between 1991 and 2004 to identify the distribution of Aedes albopictus. Adult mosquitoes were identified in 63 counties, bringing the currently known distribution of Ae. albopictus in the state to 69 of 77 counties. The widespread presence of Ae. albopictus in Oklahoma has important current and future public and veterinary health implications for surveillance and control efforts.Peer reviewedEntomology and Plant Patholog

MELDI2 Do No Harm Test Series

Mars 2020 will fly the Mars Entry, Descent, and Landing Instrumentation II (MEDLI2) sensor suite consisting of a total of seventeen instrumented thermal sensor plugs, eight pressure transducers, two heat flux sensors, and one radiometer embedded in the thermal protection system (TPS). Of the MEDLI2 instrumentation, eleven instrumented thermal plugs and seven pressure transducers will be installed on the heatshield of the Mars 2020 vehicle while the rest will be installed on the backshell. The goal of the MEDLI2 instrumentation is to directly inform the large performance uncertainties that contribute to the design and validation of a Mars entry system. A better understanding of the entry environment and TPS performance could lead to reduced design margins enabling a greater payload mass-fraction and smaller landing ellipses. To prove that the MEDLI2 system will not degrade the performance of the Mars 2020 TPS, an Aerothermal Do No Harm (DNH) test series was designed and conducted. Like Mars 2020's predecessor, Mars Science Laboratory (MSL), the heatshield material will be Phenolic Impregnated Carbon Ablator (PICA); the Mars 2020 entry conditions are enveloped by the MSL design environments, therefore the development and qualification testing performed during MEDLI is sufficient to show that the similar MEDLI2 heatshield instrumentation will not degrade PICA performance. However, given that MEDLI did not include any backshell instrumentation, the MEDLI2 team was required to design and execute a DNH test series utilizing the backshell TPS material (SLA-561V) with the intended flight sensor suite. To meet the requirements handed down from Mars 2020, the MEDLI2 DNH test series emphasized the interaction between the MEDLI2 sensors and sensing locations with the surrounding backshell TPS and substrucutre. These interactions were characterized by performing environmental testing of four 12" by 12" test panels, which mimicked the construction of the backshell TPS and the integration of the MEDLI2 sensors as seen in Figure 1. The testing included thermal vacuum/ cycling, random vibration, shock, and arc jet testing. The test panels were fabricated by Lockheed Martin, establishing techniques that will be utilized during the Mars 2020 vehicle installation. Each test panel included one thermal sensor plug (two embedded thermocouples), one heat flux sensor, and multiple pressure port holes for evaluation. This presentation will discuss the planning and execution of the MEDLI2 DNH test series. Selected highlights and results of each environmental test will be presented, and lessons learned will be addressed that will feed forward into the planning for the MEDLI2 flight system certification testing

Site-Selective Excitation And Polarized Absorption Spectra Of Nd3+ In Sr-5(Po4)(3)F And Ca-5(Po4)(3)F

Polarized absorption and fluorescence spectra were analyzed to establish individual energy (Stark) levels of Nd3+ ions in host crystals of Sr-5(PO4)(3)F (SFAP) and Ca-5(PO4)(3)F (FAP). Site-selective excitation and fluorescence facilitated differentiation between Nd3+ ions in emitting sites-associated with 1.06 mu m stimulated emission, and nonemitting Nd3+ ions in other sites. Measurements were made on samples containing different concentrations of Nd3+ at 4 K and higher temperatures. Substitution of Nd3+ for Sr2+ or Ca2+ was accompanied by passive charge compensation during crystal growth. Crystal-field splitting calculations were performed according to site for Stark levels of Nd3+ ions identified spectroscopically. We obtained a final set of crystal-field parameters B-nm for Nd3+ ions in fluorescing sites with a rms, deviation of 7 cm(-1) (52 levels in Nd:SFAP) and 8 cm(-1) (59 levels in Nd:FAP). For one of the nonemitting sites in Nd:FAP we obtained a final set of B-nm parameters which gave a rms deviation of 6 cm(-1) between 46 experimental and calculated levels