Saha Equation Normalized to Total Atomic Number

The Saha equation describes the relative number density of consecutive ionization levels of a given atomic species under conditions of thermodynamic equilibrium in an ionized gas. Because the number density in the denominator may be very small, special steps must be taken to ensure numerical stability. In this paper we recast the equation into a form in which each ionization fraction is normalized by the total number density of the atomic species, analogous to the Boltzmann equation describing the distribution of excitation states for a given ion

The General Relativistic Instability of Massive Stars

Binding energy of massive polytrope and general relativistic instability of massive star

Spruce Budworm Egg Mass Density on Balsam Fir and White Spruce: Low Population Levels (Lepidoptera: Tortricidae)

As part of a study to develop improved foliage sampling methods for spruce budworm, Choristoneura fumiferana (Clemens), egg masses, two balsam fir (four in one stand), Abies balsamea, and two white spruce, Picea glauca, trees were chosen from each of five spruce- fir stands in Michigan\u27s Upper Peninsula in 1980. All stands had very low to low population densities. Each tree was completely enumerated so that the number of new egg masses, foliage surface area, and egg mass density could be determined for the entire tree, three crown classes, four quadrants, and the tree top. Results indicated (1) considerable tree-to- tree and stand-to-stand variation; (2) no meaningful or consistent differences among quad- rants within or between species; (3) the average density in white spruce trees was 3.2 times larger than that in balsam fir trees; (4) the tree-la-tree variation of density in white spruce trees was 8.4 times larger than that in balsam fir trees; (5) densities in the mid-crown, upper-crown, and tree top are considerably higher than that in the lower-crown for both species; the relative differences for balsam fir are about twice that of white spruce; and (6) on the average, density at mid-crown was close to that of the entire tree for balsam fir, but density at mid-crown was 17.9% lower than that of the entire tree for white spruce. These results have important implications to the development of sampling plans for estimating egg mass density in spruce-fir stands

Considerations When Sampling Spruce Budworm Egg Masses on Balsam Fir and White Spruce in the Lake States: Low Population Levels

One cluster each of balsam fir, Abies balsamea, and white spruce, Picea glauca, trees was chosen from each of five stands of spruce-fir in Michigan\u27s Upper Peninsula. The foliage surface area and the number of new egg masses of the spruce budworm, Choristoneura fumiferana, were determined for each branch and the top of each tree. The effects, in terms of the bias and the variance of the estimator, of sampling in different parts of the tree and with various size branches were determined. Factors that the sampler should consider in developing sampling plans to estimate spruce bud worm egg mass densities in mixed spruce-fir stands were identified. Egg mass density and its per branch variance may be considerably higher in white spruce than in balsam fir. Sampling whole feasible branches at mid-crown yielded, in general, the most precise and accurate estimates of tree egg mass density

Bibliography of Sequential Sampling Plans in Insect Pest Management Based on Wald\u27s Sequential Probability Ratio Test

This paper contains 65 references dealing with the development of sequential sampling plans in insect pest management based on Wald\u27s Sequential Probability Ratio Test (SPRT), 25 in forest entomology and 40 in agriculture entomology. The insect(s) sampled, whether the decision procedure was based on one or two SPRTs, and the mathematical distribution and probabilities of Type I and Type II errors used to develop the SPRTs are also given for each sequential sampling plan

Regression Equations and Table for Estimating Numbers of Eggs in Jack Pine Budworm (Lepidoptera: Tortricidae) Egg Masses in Michigan

Three simple linear regression equations were developed to estimate the numbers of eggs in jack pine budworm, Choristoneura pinus pinus, egg masses in Michigan. One equation was developed for each of 2-row, 2-row +, and 3-row egg masses. A table of estimated numbers of eggs per egg mass is given for each of the three row types for egg mass lengths from 1 to 25 nun

Bit error rate measurement above and below bit rate tracking threshold

Bit error rate is measured by sending a pseudo-random noise (PRN) code test signal simulating digital data through digital equipment to be tested. An incoming signal representing the response of the equipment being tested, together with any added noise, is received and tracked by being compared with a locally generated PRN code. Once the locally generated PRN code matches the incoming signal a tracking lock is obtained. The incoming signal is then integrated and compared bit-by-bit against the locally generated PRN code and differences between bits being compared are counted as bit errors

Challenges in nucleosynthesis of trans-iron elements

© 2014 Author(s).. All article content, except where otherwise noted, is licensed under a Creative Commons Attribution 3.0 Unported License.Nucleosynthesis beyond Fe poses additional challenges not encountered when studying astrophysical processes involving light nuclei. Astrophysical sites and conditions are not well known for some of the processes involved. On the nuclear physics side, different approaches are required, both in theory and experiment. The main differences and most important considerations are presented for a selection of nucleosynthesis processes and reactions, specifically the s-, r-, γ-, and νp-processes. Among the discussed issues are uncertainties in sites and production conditions, the difference between laboratory and stellar rates, reaction mechanisms, important transitions, thermal population of excited states, and uncertainty estimates for stellar rates. The utility and limitations of indirect experimental approaches are also addressed. The presentation should not be viewed as confining the discussed problems to the specific processes. The intention is to generally introduce the concepts and possible pitfalls along with some examples. Similar problems may apply to further astrophysical processes involving nuclei from the Fe region upward and/or at high plasma temperatures. The framework and strategies presented here are intended to aid the conception of future experimental and theoretical approaches.Peer reviewe