36,565 research outputs found
Zero-loss/deflection map analysis
Experimental plots of the fraction of detected electrons removed from the
zero-loss peak, versus the fraction of incident electrons scattered outside of
the objective aperture, can serve as a robust fingerprint of object-contrast in
an energy filtered transmission electron microscope (EFTEM). Examples of this,
along with the first in a series of models for interpreting the resulting
patterns, were presented at the August 2010 meeting of the Microscope Society
of America meeting in Portland, Oregon, and published in {\em Microscopy and
MicroAnalysis} {\bf 16}, Supplement 2, pages 1534-1535 by Cambridge University
Press.Comment: 3 pages (3 figs, 4 refs) RevTeX, cf.
http://www.umsl.edu/~fraundorfp/zldeflmaps.htm
Charles M. Breder, Jr.: Bahamas and Florida
Dr. Charles M. Breder, a well known ichthyologist, kept meticulous field diaries throughout his career. This publication is a transcription of field notes recorded during the Bacon Andros Expeditions, and trips to Florida, Ohio and Illinois during the 1930s. Breder's work in Andros included exploration of a "blue hole", inland ecosystems, and collection of marine and terrestrial specimens. Anecdotes include descriptions of camping on the beach, the "filly-mingoes" (flamingos) of Andros Island, the Marine
Studios of Jacksonville, FL, a trip to Havana, and the birth of seahorses. This publication is part of a series of transcriptions of Dr. Breder's diaries. (PDF contains 55 pages
Inelastic final-state interaction
The final-state interaction in multichannel decay processes is sytematically
studied with application to B decay in mind. Since the final-state inteaction
is intrinsically interwoven with the decay interaction in this case, no simple
phase theorem like "Watson's theorem" holds for experimentally observed final
states. We first examine in detail the two-channel problem as a toy-model to
clarify the issues and to remedy common mistakes made in earlier literature.
Realistic multichannel problems are too challenging for quantitative analysis.
To cope with mathematical complexity, we introduce a method of approximation
that is applicable to the case where one prominant inelastic channel dominates
over all others. We illustrate this approximation method in the amplitude of
the decay B to pi K fed by the intermediate states of a charmed meson pair.
Even with our approximation we need more accurate information of strong
interactions than we have now. Nonethless we are able to obtain some insight in
the issue and draw useful conclusions on general fearyres on the strong phases.Comment: The published version. One figure correcte
Charles M. Breder, Jr.: Atlantis Expedition, 1934
Dr. Charles M. Breder participated on the 1934 expedition of the Atlantis from Woods Hole, Massachusetts to Panama and back and kept a field diary of daily activities. The Atlantis expedition of 1934, led by Prof. A. E. Parr, was a milestone in the history of scientific discovery in the Sargasso Sea and the West Indies. Although naturalists had visited the Sargasso Sea for many years, the Atlantis voyage was the first attempt to investigate in detailed quantitative manner biological problems about this varying, intermittent ‘false’ bottom of living, floating plants and associated fauna. In addition to Dr. Breder, the party also consisted of Dr. Alexander Forbes, Harvard University and Trustee of the Woods Hole Oceanographic Institution (WHOI); T. S. Greenwood, WHOI hydrographer; M. D. Burkenroad, Yale University’s Bingham Laboratory, carcinology and Sargasso epizoa; M. Bishop, Peabody Museum of Natural History, Zoology Dept., collections and preparations and H. Sears, WHOI ichthyologist. The itinerary included the following waypoints: Woods Hole, the Bermudas, Turks Islands, Kingston, Colon, along the Mosquito Bank off of Nicaragua, off the north coast of Jamaica, along the south coast of Cuba, Bartlett Deep, to off the Isle of Pines, through the Yucatan Channel, off Havana, off Key West, to Miami, to New York City, and then the return to Woods Hole. During the expedition, Breder collected rare and little-known flying fish species and developed a method for hatching and growing flying fish larvae. (PDF contains 48 pages
ADVANCING THROUGH RETREATING: SELF-CARE AMONG HELPING PRACTITIONERS
The research was conducted in Cape Town amongst a non-probability sample of 16 helping practitioners who are also retreatants. A literature review describes the value of retreats and retreating and informs the empirical study. The review supports the view that helping practitioners have not only the ability but also a duty to care for themselves The empirical research explores respondents’ perceptions and explanations of their retreating experience, using their own words. Six themes surrounding the meaning of retreating emerged from the data. A discussion of findings identifies the efficacy of retreating as a self-care tool among helping practitioners. Retreatants yearn for recuperative silence and reflective opportunities that remedy the stresses and pace of modern living. By retreating, they experience not only an avoidance of burnout but also an enhancement of functioning and well-being. The tools used on retreat have as much value outside the retreat setting as in it. Eight recommendations encourage the development of self-awareness and self-care practices related to retreating, including making space for this development in the workplace
The application of amino acid racemization in the acid soluble fraction of enamel to the estimation of the age of human teeth
Estimation of age-at-death for skeletonised forensic remains is one of the most significant problems in forensic anthropology. The majority of existing morphological and histological techniques are highly inaccurate, and show a bias towards underestimating the age of older individuals. One technique which has been successful in forensic age estimation is amino acid racemization in dentine. However, this method cannot be used on remains where the post-mortem interval is greater than 20 years. An alternative approach is to measure amino acid racemization in dental enamel, which is believed to be more resistant to change post-mortem. The extent of amino acid racemization in the acid soluble fraction of the enamel proteins was determined for modem known age teeth. A strong correlation was observed between the age of the tooth and the extent of racemization. No systematic bias in the direction of age estimation errors was detected. For the majority of teeth analyzed, the presence of dental caries did not affect the results obtained. In a minority of cases, carious teeth showed a higher level of racemization than would be expected given the age of the individual. These results indicate that amino acid racemization in enamel has the potential to be used in age estimation of skeletal remains. (C) 2007 Elsevier Ireland Ltd. All rights reserved
An evaluation: The potential of discarded tires as a source of fuel
The destructive distillation of rubber tire samples was studied by thermogravimetry, differential scanning calorimetry, combustion calorimetry, and mass spectroscopy. The decomposition reaction was found to be exothermic and produced a mass loss of 65 percent. The gas evolution curves that were obtained indicate that a variety of organic materials are evolved simultaneously during the decomposition of the rubber polymer
Proton configurations in the hydrogen bonds of KH2PO4 as seen by resonant x-ray diffraction
KH2PO4 (KDP) belongs to the class of hydrogen-bonded ferroelectrics, whose
paraelectric to ferroelectric phase transition is driven by the ordering of the
protons in the hydrogen bonds. We demonstrate that forbidden reflections of
KDP, when measured at an x-ray absorption edge, are highly sensitive to the
asymmetry of proton configurations. The change of average symmetry caused by
the "freezing" of the protons during the phase transition is clearly evidenced.
In the paraelectric phase, we identify in the resonant spectra of the forbidden
reflections a contribution related to the transient proton configurations in
the hydrogen bonds, which violates the high average symmetry of the sites of
the resonant atoms. The analysis of the temperature dependence reveals a change
of relative probabilities of the different proton configurations. They follow
the Arrhenius law, and the activation energies of polar and Slater
configurations are 18.6 and 7.3 meV, respectively
Computation of Brightness Temperature of Sea-foam Modelled as Sequences of Thin Phase Screens using Matlab
Sea surface temperature of the ocean is a significant climate parameter. Satellites provide data for analysing and monitoring the sea surface temperature (SST). Satellite remote sensing provide thermal data in a short duration over large area. Temperature measurement by remote sensing is dependent on the principle that most objects emit electromagnetic (EM) radiation corresponding to temperature, wavelength and emissivity of the objects. Brightness temperatures are detected by thermal sensors, however, brightness temperature coincides with the real temperature of objects if they are black bodies. In this paper, we estimated the effective dielectric constant of sea foam layer which is a very important parameter in investigating ocean brightness temperature. This was done at WindSat frequencies and using a discretization method to evaluate the dielectric constant of a random distribution of air-bubbles discretized into slices of sea foam layer. For efficient evaluation of scattering by foam covered sea surface and measurement of brightness temperature in milli-Kelvin, we develop a discrete based physical model of sea foam which provides accurate estimate of the complex effective dielectric constant of sea foam. The foam covered sea foam layer is modelled as sequences of thin phase screens ( slices ofsea foam layer) with equal depth . Each layer comprised of random distribution of bubbles that follows a log-normal distribution pattern with geometrical and optical properties such as foam layer thickness, foam void fraction, foam volume fraction, sea surface temperature and sea surface salinity. Results of sea surface emissivity and brightness temperature as a function of polarization, angle of incidence, WindSat frequencies and thickness of sea foam are presented
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