8,903 research outputs found

    Correlations in nuclear energy recurrence relations

    Full text link
    The excitation energies of states belonging to the ground state bands of heavy even-even nuclei are analysed using recurrence relations. Excellent agreement with experimental data at the 10 keV level is obtained by taking into account strong correlations which emerge in the analysis. This implies that the excitation energies can be written as a polynomial of maximum degree four in the angular momentum.Comment: 4 pages, 1 figure, 1 table, 9 reference

    The development of a cislunar space infrastructure

    Get PDF
    The primary objective of this Advanced Mission Design Program is to define the general characteristics and phased evolution of a near-Earth space infrastructure. The envisioned foundation includes a permanently manned, self-sustaining base on the lunar surface, a space station at the Libration Point between earth and the moon (L1), and a transportation system that anchors these elements to the Low Earth Orbit (LEO) station. The implementation of this conceptual design was carried out with the idea that the infrastructure is an important step in a larger plan to expand man's capabilities in space science and technology. Such expansion depends on low cost, reliable, and frequent access to space for those who wish to use the multiple benefits of this environment. The presence of a cislunar space infrastructure would greatly facilitate the staging of future planetary missions, as well as the full exploration of the lunar potential for science and industry. The rationale for, and a proposed detailed scenario in support of, the cislunar space infrastructure are discussed

    Science is perception: what can our sense of smell tell us about ourselves and the world around us?

    Get PDF
    Human sensory processes are well understood: hearing, seeing, perhaps even tasting and touch—but we do not understand smell—the elusive sense. That is, for the others we know what stimuli causes what response, and why and how. These fundamental questions are not answered within the sphere of smell science; we do not know what it is about a molecule that … smells. I report, here, the status quo theories for olfaction, highlighting what we do not know, and explaining why dismissing the perception of the input as ‘too subjective’ acts as a roadblock not conducive to scientific inquiry. I outline the current and new theory that conjectures a mechanism for signal transduction based on quantum mechanical phenomena, dubbed the ‘swipe card’, which is perhaps controversial but feasible. I show that such lines of thinking may answer some questions, or at least pose the right questions. Most importantly, I draw links and comparisons as to how better understanding of how small (10’s of atoms) molecules can interact so specially with large (10 000’s of atoms) proteins in a way that is so integral to healthy living. Repercussions of this work are not just important in understanding a basic scientific tool used by us all, but often taken for granted, it is also a step closer to understanding generic mechanisms between drug and receptor, for example

    Desynchronization of pulse-coupled oscillators with delayed excitatory coupling

    Full text link
    Collective behavior of pulse-coupled oscillators has been investigated widely. As an example of pulse-coupled networks, fireflies display many kinds of flashing patterns. Mirollo and Strogatz (1990) proposed a pulse-coupled oscillator model to explain the synchronization of South East Asian fireflies ({\itshape Pteroptyx malaccae}). However, transmission delays were not considered in their model. In fact, the presence of transmission delays can lead to desychronization. In this paper, pulse-coupled oscillator networks with delayed excitatory coupling are studied. Our main result is that under reasonable assumptions, pulse-coupled oscillator networks with delayed excitatory coupling can not achieve complete synchronization, which can explain why another species of fireflies ({\itshape Photinus pyralis}) rarely synchronizes flashing. Finally, two numerical simulations are given. In the first simulation, we illustrate that even if all the initial phases are very close to each other, there could still be big variations in the times to process the pulses in the pipeline. It implies that asymptotical synchronization typically also cannot be achieved. In the second simulation, we exhibit a phenomenon of clustering synchronization

    Electromagnetic Transition Strengths in Heavy Nuclei

    Full text link
    We calculate reduced B(E2) and B(M1) electromagnetic transition strengths within and between K-bands in support of a recently proposed model for the structure of heavy nuclei. Previously, only spectra and a rough indication of the largest B(E2) strengths were reported. The present more detailed calculations should aid the experimental identification of the predicted 0+0^+, 1+1^+ and 2+2^+ bands and, in particular, act to confirm or refute the suggestion that the model 0+0^+ and 2+2^+ bands correspond to the well known and widespread beta and gamma bands. Furthermore they pinpoint transitions which can indicate the presence of a so far elusive 1+1^+ band by feeding relatively strongly into or out of it. Some of these transitions may already have been measured in 230^{230}Th, 232^{232}Th and 238^{238}U.Comment: 10 pages, 1 Figure, submitted to Physical Review

    Dairy and hog farming in northeastern Iowa

    Get PDF
    On Northeastern Iowa dairy and hog farms, highest returns were obtained where the number of milk cows equaled litters of pigs. This meant about 6 pounds of hogs were produced to each pound of butterfat. Where hog production was less, returns were lower. The butterfat-hog price ratio, during the years of the study, favored hogs, with 1 pound butterfat worth only 3.5 pounds of hogs. Generally, the strictly dairy herds were more profitable than the dual-purpose herds, even though butterfat prices were unfavorable in comparison to beef, during the period studied. Income from beef in the dual-purpose herds was not enough to offset the lower sales of butterfat. The dairy herds, with 16.6 cows, averaged 229 pounds butterfat sold or used in the household, and 493 pounds beef per cow, while the dual-purpose herds, with 14.1 cows, averaged 162 pounds butterfat output and 711 pounds beef per cow
    corecore