10,316 research outputs found
Quantum fluctuations of the electroweak sphaleron: Erratum and Addendum
We correct an error in our treatment of the tadpole contribution to the
fluctuation determinant of the sphaleron, and also a minor mistake in a
previous estimate. Thereby the overall agreement between the two existing exact
computations and their consistency with the estimate is improved considerably.Comment: 4 pages, Dortmund preprint DO-TH-93/19E
The Rachel Carson Letters and the Making of Silent Spring
Environment, conservation, green, and kindred movements look back to Rachel Carson’s 1962 book Silent Spring as a milestone. The impact of the book, including on government, industry, and civil society, was immediate and substantial, and has been extensively described; however, the provenance of the book has been less thoroughly examined. Using Carson’s personal correspondence, this paper reveals that the primary source for Carson’s book was the extensive evidence and contacts compiled by two biodynamic farmers, Marjorie Spock and Mary T. Richards, of Long Island, New York. Their evidence was compiled for a suite of legal actions (1957-1960) against the U.S. Government and that contested the aerial spraying of dichlorodiphenyltrichloroethane (DDT). During Rudolf Steiner’s lifetime, Spock and Richards both studied at Steiner’s Goetheanum, the headquarters of Anthroposophy, located in Dornach, Switzerland. Spock and Richards were prominent U.S. anthroposophists, and established a biodynamic farm under the tutelage of the leading biodynamics exponent of the time, Dr. Ehrenfried Pfeiffer. When their property was under threat from a government program of DDT spraying, they brought their case, eventually lost it, in the process spent US$100,000, and compiled the evidence that they then shared with Carson, who used it, and their extensive contacts and the trial transcripts, as the primary input for Silent Spring. Carson attributed to Spock, Richards, and Pfeiffer, no credit whatsoever in her book. As a consequence, the organics movement has not received the recognition, that is its due, as the primary impulse for Silent Spring, and it is, itself, unaware of this provenance
Biologic effects of oil fly ash.
Epidemiologic studies have demonstrated increased human morbidity and mortality with elevations in the concentration of ambient air particulate matter (PM). Fugitive fly ash from the combustion of oil and residual fuel oil significantly contributes to the ambient air particle burden. Residual oil fly ash (ROFA) is remarkable in the capacity to provoke injury in experimental systems. The unique composition of this emission source particle makes it particularly useful as a surrogate for ambient air PM in studies of biologic effects testing the hypothesis that metals mediate the biologic effects of air pollution particles. A majority of the in vitro and animal model investigations support the postulate that transition metals present in ROFA (especially vanadium) participate in Fenton-like chemical reactions to produce reactive oxygen species. This is associated with tyrosine phosphorylation, nuclear factor kappa B and other transcription factor activation, induction of inflammatory mediator expression, and inflammatory lung injury. It is also evident that vanadium accounts for a significant portion of the biologic activity of ROFA. The extrapolation of this body of investigation on ROFA to the field of ambient air PM is difficult, as particles in numerous environments have such small amounts of vanadium
Quantum Fluctuations around the Electroweak Sphaleron
We present an analysis of the quantum fluctuations around the electroweak
sphaleron and calculate the associated determinant which gives the 1--loop
correction to the sphaleron transition rate. The calculation differs in various
technical aspects from a previous analysis by Carson et al. so that it can be
considered as independent. The numerical results differ also -- by several
orders of magnitude -- from those of this previous analysis; we find that the
sphaleron transition rate is much less suppressed than found previously.Comment: DO-TH-93/19 39 pages, 5 figures (available on request as Postscript
files or via Fax or mail), LaTeX, no macros neede
Low Head Power Generation With Bulb Turbines
Because of uncertainties, delays, and high costs associated with alternative electric energy sources, many agencies responsible for generation of electrical power are investigating means of replacing or supplementing their existing hydroelectric facilities. In the head range between 10 and 60 feet, the bulb-type generating unit, in which the generator is enclosed in a metal capsule within the water passage, has many advantages, including higher efficiency and lower cost, over other types of turbines. Two of the municipalities in the United States which have recently conducted feasibility studies for installing bulb turbines in their systems are the City of Idaho Falls, Idaho, and the City of Vanceburg, Kentucky. For the City of Idaho Falls, International Engineering Company, Inc. prepared feasibility studies which demonstrated that for 7 MW units installed in existing plants, (I) bulb turbines are more economical than comparable conventional (vertical shaft Kaplan) units, (2) installation of new bulb turbine units is preferable to rehabilitating and/or relocating the existing generating units, and (3) the cost of energy generated by the proposed bulb turbine installations would be less than that from alternative sources of energy. At locations at existing dams on the Ohio River, the Vanceburg Electric Light, Heat and Power System studied installations comprised of 3 - 23 MW bulb turbines per plant and also found that the cost of energy from these facilities would be less than from other sources
Application of Airborne Gamma Ray Spectrometric Surveys Meguma Terrane, Nova Scotia
Between 1976 and 1983 a series of airborne gamma-ray spectrometric surveys with flight lines spaced at one kilometer intervals were carried out in the Province of Nova Scotia. These surveys covered most of the Meguma Terrane and have yielded radioelement distribution patterns that have proven useful in delineating various aspects of the region's geology.
Within a cogenetic suite of Devonian-Carboniferous peraluminous granitic rocks uranium concentrations are shown to increase progressively with increasing differentiation while thorium concentrations reflect two contrasting trends- The most prevalent trend, shown by the granitic rocks of the eastern part of the South Mountain Batholith (New Ross area) and Eastern Meguma Terrane, is one of decreasing thorium concentrations with increasing differentiation. A second, less prominent trend exhibited by the granitic rocks of the western part of the South Mountain Batholith shows increasing thorium concentrations with increasing differentiation. The more prevalent inverse relationship between uranium and thorium results in high eU/eTh ratios associated with the more differentiated phases of the granitic suite. In addition, certain slate units of the Meguma Group are shown to have distinctly higher radioelement contents, in particular thorium, compared to the other slate units and the remainder of the Meguma Group.
Follow-up investigations of these airborne gamma-ray spectrometric surveys have confirmed the relationships between uranium and thorium. Limited lithogeochemical sampling has shown that those phases of the granitic suite which exhibit a high eU/eTh ratio also exhibit increased levels of other lithophlle elements, Sn and Be and occasionally Li and F.
RÉSUMÉ
Entre 1976 et 1983 une série de levées de terrains spectomètrlque aérien de rayons gamma, avec des lignes de vois éspacées à intervals d'un kilomètre, ont été effectuées dans la province de la Nouvelle Écosse. Ces levées s'étendent sur la pluspart du terrain Meguma et ont fourni aes pattrons de distribution d'éléments radioactifs qui ont été utiles pour décrire divers aspects de la géologie de la région.
Dans une suite Dévoniene-Carbonifère cogénétique de roches granitiques per-alumineuse, il a été démonté que les concentrations d' uranium augmentent progressivement avec des hausses de dlfférenciations alors que les concentrations de thorium montrent deux tendences contrastantes. La tendence la plus dominante, démontrée par les roches granitiques du batholithe de la "South Mountain", (région de New Ross) et du terrain "Eastern Meguma", est une baisse de concentration de thorium avec un accroissement de différenciation. Une autre tendance, moins accentuée, exposée par les roches granitiques de la partie de l'ouest du batholithe de la "South Mountain" montre une hausse des concentrations de thorium avec une hausse de différenciation. Les rélations inverses les plus dominantes entre l'uranium et le thorium donnent des rapports eU/eTh, qui sont associés avec les phases plus différenciees de la suite granitique. De plus, certaines unités d'ardoise du groupe Meguma, ont des teneurs d'éléments radioactlf qui sont nettement plus élevées, surtout pour le thorium, cooparé aux autres unités d'ardoise dans le reste du groupe Meguma.
De plus amples investigations de ces levées spectrometriques à rayons gamma, ont confirmé les rélations entre l'uranium et le thorium. Des prévèlements d'échantlllons limite de géochimie, ont demontré ces phases de la suite granitique, qui exposent de hautes proportions de eU/eTh, comprennent aussi des niveaux élevés d'autres éléments, lithophiles, Sn, Be, et desfois Li et F.
[Traduit par le journal
Apollo experience report: Development of the extravehicular mobility unit
The development and performance history of the Apollo extravehicular mobility unit and its major subsystems is described. The three major subsystems, the pressure garment assembly, the portable life-support system, and the oxygen purge system, are defined and described in detail as is the evolutionary process that culminated in each major subsystem component. Descriptions of ground-support equipment and the qualification testing process for component hardware are also presented
Intra-individual movement variability during skill transitions: A useful marker?
Applied research suggests athletes and coaches need to be challenged in knowing when and how much a movement should be consciously attended to. This is exacerbated when the skill is in transition between two more stable states, such as when an already well learnt skill is being refined. Using existing theory and research, this paper highlights the potential application of movement variability as a tool to inform a coach’s decision-making process when implementing a systematic approach to technical refinement. Of particular interest is the structure of co-variability between mechanical degrees-of-freedom (e.g., joints) within the movement system’s entirety when undergoing a skill transition. Exemplar data from golf are presented, demonstrating the link between movement variability and mental effort as an important feature of automaticity, and thus intervention design throughout the different stages of refinement. Movement variability was shown to reduce when mental effort directed towards an individual aspect of the skill was high (target variable). The opposite pattern was apparent for variables unrelated to the technical refinement. Therefore, two related indicators, movement variability and mental effort, are offered as a basis through which the evaluation of automaticity during technical refinements may be made
Report of the sensor readout electronics panel
The findings of the Sensor Readout Electronics Panel are summarized in regard to technology assessment and recommended development plans. In addition to two specific readout issues, cryogenic readouts and sub-electron noise, the panel considered three advanced technology areas that impact the ability to achieve large format sensor arrays. These are mega-pixel focal plane packaging issues, focal plane to data processing module interfaces, and event driven readout architectures. Development in each of these five areas was judged to have significant impact in enabling the sensor performance desired for the Astrotech 21 mission set. Other readout issues, such as focal plane signal processing or other high volume data acquisition applications important for Eos-type mapping, were determined not to be relevant for astrophysics science goals
The Higher Derivative Expansion of the Effective Action by the String-Inspired Method, Part I
The higher derivative expansion of the one-loop effective action for an
external scalar potential is calculated to order O(T**7), using the
string-inspired Bern-Kosower method in the first quantized path integral
formulation. Comparisons are made with standard heat kernel calculations and
with the corresponding Feynman diagrammatic calculation in order to show the
efficiency of the present method.Comment: 13 pages, Plain TEX, 1 figure may be obtained from the authors,
HD-THEP-93-4
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