Versatile ytterbium ion trap experiment for operation of scalable ion-trap chips with motional heating and transition-frequency measurements

We present the design and operation of an ytterbium ion trap experiment with a setup offering versatile optical access and 90 electrical interconnects that can host advanced surface and multilayer ion trap chips mounted on chip carriers. We operate a macroscopic ion trap compatible with this chip carrier design and characterize its performance, demonstrating secular frequencies >1 MHz, and trap and cool nearly all of the stable isotopes, including 171Yb+ ions, as well as ion crystals. For this particular trap we measure the motional heating rate 〈ṅ〉 and observe an 〈ṅ〉∝1/ω2 behavior for different secular frequencies ω. We also determine a spectral noise density SE(1 MHz)=3.6(9)×10-11 V2 m-2 Hz-1 at an ion electrode spacing of 310(10) μm. We describe the experimental setup for trapping and cooling Yb+ ions and provide frequency measurements of the 2S1/2↔2P1/2 and 2D3/2↔3D[3/2]1/2 transitions for the stable 170Yb+, 171Yb+, 172Yb+, 174Yb+, and 176Yb+ isotopes which are more precise than previously published work

Supersolutions for a class of semilinear heat equations

A semilinear heat equation $u_{t}=\Delta u+f(u)$ with nonnegative initial data in a subset of $L^{1}(\Omega)$ is considered under the assumption that $f$ is nonnegative and nondecreasing and $\Omega\subseteq \R^{n}$. A simple technique for proving existence and regularity based on the existence of supersolutions is presented, then a method of construction of local and global supersolutions is proposed. This approach is applied to the model case $f(s)=s^{p}$, $\phi\in L^{q}(\Omega)$: new sufficient conditions for the existence of local and global classical solutions are derived in the critical and subcritical range of parameters. Some possible generalisations of the method to a broader class of equations are discussed.Comment: Expanded version of the previous submission arXiv:1111.0258v1. 14 page

Antithrombotic therapy after myocardial reperfusion in acute myocardial infarction

AbstractThe problem of post-thrombolytic reocclusion can be approached in several ways. 1) Better thrombolytic agents with longer duration of effects and more powerful properties aimed at enhanced clot lysis and anticoagulation are under study. 2) The combination of high dose heparin and low dose aspirin is proposed for all patients with an acute myocardial infarction treated with thrombolytic agents. 3) Peptide inhibitors of thrombin and monoclonal antibodies against platelet glycoprotein receptors and adhesive macromolecules are potentially effective inhibitors of platelet aggregation and thrombus formation during or after thrombolytic therapy

Overwinter Growth and Survival of Largemouth Bass: Interactions among Size, Food, Origin, and Winter Severity

Winter severity (temperature, duration, and photocycle), geographic origin, food availability, and initial body size likely influence growth, survival, and, therefore, recruitment of age-0 largemouth bass Micropterus salmoides. We collected age-0 largemouth bass (70–160 mm total length) from low (33N), intermediate (40N), and high (45N) latitudes throughout their natural range (origin), and we subjected all three groups of fish to three experimental winters that mimicked these latitudes (N = 9 largemouth bass per treatment). Within each winter and origin, one-half of the largemouth bass were fed fish prey, whereas the remaining one-half were starved. Winter strongly influenced survival; overall survival rates in the high-, intermediate-, and low-latitude winters were 34.9, 59.4, and 61.1%, respectively (x2 test, P < 0.05). Largemouth bass from 33N suffered high mortality in the high-latitude winter. Across all winters, more fed fish (64.5%) survived than did starved fish (38.1%) (x2 test, P =100 mm) size classes revealed that more small fish died than did large fish in the low- and high-latitude winters, but this was not the case in the middle-latitude winter. Wet weights (g) of fed largemouth bass increased, remained constant, and declined in the low-, intermediate-, and high-latitude winters, respectively. Wet weights and total energy content (kJ) of fed individuals were consistently higher than those of their starved counterparts in all winters. However, energy density (kJ/g) of fed individuals often declined to levels similar to those of starved largemouth bass. Winter temperature combined with duration likely dictate the northern limit of largemouth bass by reducing growth, even when food is abundant. Because survival of individuals from the low latitude was poor in higher latitude winters, stocking southern largemouth bass in northern systems may translate to high mortality and perhaps to degradation of physiological tolerances of local populations through hybridization.This research was funded by National Science Foundation grant DEB 9407859 and associated Research Experiences for Undergraduates supplement to A. H. Fullerton and by Federal Aid in Sport Fish Restoration project F-69-P, administered jointly by the U.S. Fish and Wildlife Service and the Ohio Division of Wildlife. A Presidential Fellowship from The Ohio State University supported J. E. Garvey

Predicting How Winter Affects Energetics of Age-0 Largemouth Bass: How Do Current Models Fare?

During the first winter of life, loss of energy reserves as a function of low feeding activity and scarce prey may contribute to high mortality of age-0 largemouth bass Micropterus salmoides. To explore how two current bioenergetics models predict winter energy depletion, we quantified growth and consumption by age-0 largemouth bass from Alabama, Ohio, and Wisconsin fed maintenance rations in 55-L aquaria in three simulated winters mimicking temperatures and photoperiods at low temperate latitudes (Alabama; 33N), middle latitudes (Ohio; 40N), and high temperate latitudes (Wisconsin; 46N).We compared observed growth in aquaria with that predicted by putting observed consumption into both models. During winter 1995–1996, we validated one of the models with a separate pool experiment (5,800-L) in which age-0 largemouth bass were fed either at 0.5 X or 1.5 X maintenance ration. In aquaria, energy density of the largemouth bass declined in the high- and middle- but not in the low-latitude winter. Though error was slight in the low- and middle-latitude winters for one of the models, both models underestimated growth in the high-latitude winter. To fit the model to the data, the function that estimates weight-specific resting metabolism had to be reduced by about 16%. In pools, where we predicted consumption from observed growth, the model adequately predicted consumption by largemouth bass fed 1.5 X maintenance, but overestimated consumption by 0.5 X maintenance individuals. Current bioenergetics models perform poorly at the cold temperatures (<6C), photoperiods, and low prey abundances typical of high-latitude lakes, likely because metabolic costs are overestimated.This research was funded by National Science Foundation grant DEB 9407859 to R.A.S. and Federal Aid in Sport Fish Restoration Project F-69-P, administered jointly by the U.S. Fish and Wildlife Service and the Ohio Division of Wildlife. A University PostDoctoral Fellowship and a Presidential Fellowship from The Ohio State University supported R.A.W. and J.E.G., respectively, during part of this work

Evaluating How Local- and Regional-Scale Processes Interact to Regulate Growth of Age-0 Largemouth Bass

Regional- and local-scale processes may interact to influence early growth and survival, thereby governing cohort strength. During summer through fall 1994–1996, we assessed how precipitation (a regional-scale process) and prey availability (a local-scale process) influenced piscivory and growth of age-0 largemouth bass Micropterus salmoides in five Ohio reservoirs (190–1,145 ha). We expected early growth to vary with the abundance and relative sizes of age- 0 gizzard shad Dorosoma cepedianum. We collected age-0 largemouth bass and prey fishes every 3 weeks in each reservoir. In 1994, May precipitation was low (total = 4 cm), resulting in low mean daily reservoir discharge (x¯5 reservoirs = 3.6 m3/s). In four reservoirs, stable water levels may have led to successful largemouth bass reproduction and perhaps an early hatch. As such, age-0 largemouth bass in these systems were abundant, consumed gizzard shad, and reached large sizes by fall (15.3 g). In 1995 and 1996, high precipitation (total > 12 cm) and high reservoir discharge [x¯5 reservoirs = 13.8 m3/s (1995), 28.8 m3/s (1996)] in some reservoirs in May likely reduced largemouth bass abundances. Growth during these years was density dependent across reservoirs. When age-0 largemouth bass abundance was low, nonshad prey fish were consumed, and mean fall sizes were similar to those in 1994 (12.0 g). Conversely, fall weights (4.5–7.4 g) declined in reservoirs with increasing largemouth bass density. Surveying May precipitation in Ohio across 48 years revealed that conditions like those in 1994 occurred less than 15% of the time. Because gizzard shad should rarely be available and other prey fish species probably are limited, density-dependent processes should often regulate early piscivory, growth, and potentially, cohort strength in these systems.This research was funded by National Science Foundation grant DEB 9407859 to RAS and Federal Aid in Sport Fish Restoration project F-69-P, administered jointly by the U.S. Fish and Wildlife Service and the Ohio Division of Wildlife. A Postdoctoral Fellowship and Presidential Fellowship from The Ohio State University supported RAW and JEG, respectively, during part of this work