Automatic navigation of a long range rocket vehicle

The flight of a rocket vehicle in the equatorial plane of a rotating earth is considered with possible disturbances in the atmosphere due to changes in density, in temperature, and in wind speed. These atmospheric disturbances together with possible deviations in weight and in moment of inertia of the vehicle tend to change the flight path away from the normal flight path. The paper gives the condition for the proper cut-off time for the rocket power, and the proper corrections in the elevator angle so that the vehicle will land at the chosen destination in spite of such disturbances. A scheme of tracking and automatic navigation involving a high-speed computer and elevator servo is suggested for this purpose

Systematic errors due to linear congruential random-number generators with the Swendsen-Wang algorithm: A warning

We show that linear congruential pseudo-random-number generators can cause systematic errors in Monte Carlo simulations using the Swendsen-Wang algorithm, if the lattice size is a multiple of a very large power of 2 and one random number is used per bond. These systematic errors arise from correlations within a single bond-update half-sweep. The errors can be eliminated (or at least radically reduced) by updating the bonds in a random order or in an aperiodic manner. It also helps to use a generator of large modulus (e.g. 60 or more bits).Comment: Revtex4, 4 page

Tailoring Communication about Suburban Deer Management to Stakeholders' Concerns

Click on the PDF for an Executive Summary and the full report. Visit the HDRU website for a complete listing of HDRU publications at: http://hdru.dnr.cornell.edu

Communicating about Suburban Deer Management: Tailoring the Message to the Stakeholders

Public input plays an important role in selecting suburban deer management alternatives. Agencies often communicate with the public to ensure that citizens have accurate information when judging management alternatives. Research has shown that suburban residents evaluate deer management alternatives on the basis of different sets of criteria (e.g., effectiveness, humaneness, etc.). We explored whether people\u27s attitudes were more likely to be influenced by information if it addressed the criteria about which they were concerned. We conducted our research through two mail surveys of randomly selected residents of Irondequoit, New York, implemented 20 months apart. Some 512 people responded to both surveys. The first survey was used to: (I) determine those considerations respondents used to judge deer management alternatives; and (2) measure their attitudes toward contraception and other alternatives. We used these results to categorize respondents according to how important it was to them that a deer management method be: (1) effective; and (2) humane. The second survey contained a subset of questions from the first survey. Three versions of the second questionnaire were used, varying in the type of explanatory information contained: (1) effectiveness of contraception; (2) humaneness of contraception; or (3) neither topic. We used general linear models and logistic regression models to explore whether receiving effectiveness or humaneness information influenced attitudes toward contraception and whether the effect of the information was influenced by how important the concern described in the information was to respondents. We found that people were more likely to change their opinion about contraception if they received information addressing their concerns

Communicating about suburban deer management: Tailoring the message to the stakeholders

Public input plays an important role in selecting suburban deer management alternatives. Agencies often communicate with the public to ensure that citizens have accurate information when judging management alternatives. Research has shown that suburban residents evaluate deer management alternatives on the basis of different sets of criteria (e.g., effectiveness, humaneness, etc.). We explored whether people\u27s attitudes were more likely to be influenced by information if it addressed the criteria about which they were concerned. We conducted our research through two mail surveys of randomly selected residents of Irondequoit, New York, implemented 20 months apart. Some 512 people responded to both surveys. The first survey was used to: (1) determine those considerations respondents used to judge deer management alternatives; and (2) measure their attitudes toward contraception and other alternatives. We used these results to categorize respondents according to how important it was to them that a deer management method be: (1) effective; and (2) humane. The second survey contained a subset of questions from the first survey. Three versions of the second questionnaire were used, varying in the type of explanatory information contained: (1) effectiveness of contraception; (2) humaneness of contraception; or (3) neither topic. We used general linear models and logistic regression models to explore whether receiving effectiveness or humaneness information influenced attitudes toward contraception and whether the effect of the information was influenced by how important the concern described in the information was to respondents. We found that people were more likely to change their opinion about contraception if they received information addressing their concerns

Knuthian Drawings of Series-Parallel Flowcharts

Inspired by a classic paper by Knuth, we revisit the problem of drawing flowcharts of loop-free algorithms, that is, degree-three series-parallel digraphs. Our drawing algorithms show that it is possible to produce Knuthian drawings of degree-three series-parallel digraphs with good aspect ratios and small numbers of edge bends.Comment: Full versio

Revealing Relationships among Relevant Climate Variables with Information Theory

A primary objective of the NASA Earth-Sun Exploration Technology Office is to understand the observed Earth climate variability, thus enabling the determination and prediction of the climate's response to both natural and human-induced forcing. We are currently developing a suite of computational tools that will allow researchers to calculate, from data, a variety of information-theoretic quantities such as mutual information, which can be used to identify relationships among climate variables, and transfer entropy, which indicates the possibility of causal interactions. Our tools estimate these quantities along with their associated error bars, the latter of which is critical for describing the degree of uncertainty in the estimates. This work is based upon optimal binning techniques that we have developed for piecewise-constant, histogram-style models of the underlying density functions. Two useful side benefits have already been discovered. The first allows a researcher to determine whether there exist sufficient data to estimate the underlying probability density. The second permits one to determine an acceptable degree of round-off when compressing data for efficient transfer and storage. We also demonstrate how mutual information and transfer entropy can be applied so as to allow researchers not only to identify relations among climate variables, but also to characterize and quantify their possible causal interactions.Comment: 14 pages, 5 figures, Proceedings of the Earth-Sun System Technology Conference (ESTC 2005), Adelphi, M

Greater Forearm Blood Flow is Associated With Higher Physical Activity in Older Individuals

Please refer to the pdf version of the abstract located adjacent to the title

Origin of Complex Quantum Amplitudes and Feynman's Rules

Complex numbers are an intrinsic part of the mathematical formalism of quantum theory, and are perhaps its most mysterious feature. In this paper, we show that the complex nature of the quantum formalism can be derived directly from the assumption that a pair of real numbers is associated with each sequence of measurement outcomes, with the probability of this sequence being a real-valued function of this number pair. By making use of elementary symmetry conditions, and without assuming that these real number pairs have any other algebraic structure, we show that these pairs must be manipulated according to the rules of complex arithmetic. We demonstrate that these complex numbers combine according to Feynman's sum and product rules, with the modulus-squared yielding the probability of a sequence of outcomes.Comment: v2: Clarifications, and minor corrections and modifications. Results unchanged. v3: Minor changes to introduction and conclusio

Subventricular zone stem cells are heterogeneous with respect to their embryonic origins and neurogenic fates in the adult olfactory bulb

Wedetermined the embryonic origins of adult forebrain subventricular zone (SVZ) stem cells by Cre-lox fate mapping in transgenic mice. We found that all parts of the telencephalic neuroepithelium, including the medial ganglionic eminence and lateral ganglionic eminence (LGE) and the cerebral cortex, contribute multipotent, self-renewing stem cells to the adult SVZ. Descendants of the embryonic LGE and cortex settle in ventral and dorsal aspects of the dorsolateral SVZ, respectively. Both populations contribute new (5-bromo-2(')-deoxyuridine- labeled) tyrosine hydroxylase- and calretinin-positive interneurons to the adult olfactory bulb. However, calbindin-positive interneurons in the olfactory glomeruli were generated exclusively by LGE- derived stem cells. Thus, different SVZ stem cells have different embryonic origins, colonize different parts of the SVZ, and generate different neuronal progeny, suggesting that some aspects of embryonic patterning are preserved in the adult SVZ. This could have important implications for the design of endogenous stem cell-based therapies in the future