21,224 research outputs found
An objective method for forecasting tropical cyclone intensity and motion using Nimbus-5 ESMR measurements and non-satellite derived descriptors
An empirical analysis program, based on finding an optimal representation of the data was applied to 120 observations of 29 1973 and 1974 North Pacific tropical cyclones. Each observation consists of a field of Nimbus-5 Electrically Scanning Microwave Radiometer radiation measurements at 267 grid points covering and surrounding the tropical cyclone plus nine other non-satellite derived discriptors. Forecast algorithms to estimate storm intensity and motion at 12, 24, 48, and 72 hours after each observation were developed using an independent eigen screening analysis. These algorithms were based on best track data. Independent testing of these algorithms showed that the performance of most of these algorithms were better than persistence and the algorithms forecasting 24, 48, and 72 hour maximum wind speed were better than those made operationally by the Joint Typhoon Warning Center for 1973 and 1974 that did not use best track data
New light on the âDrummer of Tedworthâ: conflicting narratives of witchcraft in Restoration England
This paper presents a definitive text of hitherto little-known early documents concerning âThe Drummer of Tedworthâ, a poltergeist case that occurred in 1662-3 and became famous not least due to its promotion by Joseph Glanvill in his demonological work, Saducismus Triumphatus. On the basis of these and other sources, it is shown how responses to the events at Tedworth evolved from anxious piety on the part of their victim, John Mompesson, to confident apologetic by Glanvill, before they were further affected by the emergence of articulate scepticism about the case
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High-Frequency Measurements Of The Spectrum Of Sagittarius A*
We report near-simultaneous interferometric measurements of the spectrum of Sagittarius A* over the 5-354 GHz range and single-dish observations that have yielded the first detection of Sgr A* at 850 GHz. We confirm that Sgr A*'s spectrum rises more steeply at short millimeter wavelengths than at centimeter wavelengths, leading to a near-millimeter/submillimeter excess that dominates its luminosity. Below 900 GHz, Sgr A*'s observed luminosity is 70 +/- 30 L.. A new upper limit to Sgr A*'s 24.3 mu m flux, together with a compilation of other extant IR data, imply a far-infrared spectral turnover, which can result from either an intrinsic synchrotron cutoff or excess extinction near Sgr A*. If the former applies, Sgr A*'s total synchrotron luminosity is <10(3) L., while in the latter case it is <3 x 10(4) L. if spherical symmetry also applies.NSF AST96-15025, AST96-13717Astronom
Shoot Heterogeneity Effects on Shiraz/Richter 99 Grapevines. I. Vegetative Growth
In this study the vegetative growth parameters of normally developed and underdeveloped shoots were compared in an attempt to quantify shoot heterogeneity in a Shiraz/Richter 99 vineyard. A field trial was performed in the Stellenbosch area,Western Cape, South Africa. Comparisons based on certain vegetative growth parameters were made between normally developed and underdeveloped shoots from both shaded and well-exposed canopies. The longer primary shoots of the normally developed shoots matured earlier in the season, with less apparent competition between shoot lignification and grape ripening. Reserves were more evenly distributed in these shoots. Total starch content over the whole shoot was found to be higher in the normally developed shoots, particularly when wellexposed. More and longer secondary shoots occurred on the normally developed shoots than on the underdeveloped shoots. No difference was found in the number of primary leaves (leaves on primary shoots) betweennormally developed and underdeveloped shoots, although the leaf area was much larger in the case of the former. Normally developed shoots had more and larger secondary leaves (leaves on secondary shoots), while all the leaves that developed in the shaded canopies were found to be larger than those in the well-exposed canopies with a higher leaf area:mass ratio. The normally developed shoots seemed to have a greater potential for producing a higher yield, with better quality, than the underdeveloped shoots, as they have a more desirable leaf area composition in addition to a larger total leaf area per shoot
Type I Superconductivity in YbSb2 Single Crystals
We present evidence of type I superconductivity in YbSb2 single crystals,
from DC and AC magnetization, heat capacity and resistivity measurements. The
critical temperature and critical field are determined to be 1.3 K
and 55 Oe. A small Ginzburg-Landau parameter \kappa = 0.05,
together with typical magnetization isotherms of type I superconductors, small
critical field values, a strong Differential Paramagnetic Effect (DPE) signal,
and a field-induced change from second to first order phase transition, confirm
the type I nature of the superconductivity in YbSb2. A possible second
superconducting state is observed in the radiofrequency (RF) susceptibility
measurements, with 0.41 K and 430 Oe.Comment: 6 pages, 10 figure
Shoot Heterogeneity Effects on Shiraz/Richter 99 Grapevines. II. Physiological Activity
In this study, the physiology of normally developed and underdeveloped shoots is compared in an attempt toquantify the effect of shoot heterogeneity in a Shiraz/Richter 99 vineyard, located in the Stellenbosch area of theWestern Cape, South Africa. Comparisons are made between normally developed and underdeveloped shoots fromshaded and well-exposed canopies. In the first five weeks after véraison, photosynthetic and transpiration rates,stomatal conductance and water-use efficiency (WUE) decreased as berry ripening progressed, while the internalCO2 levels of the leaves increased. Since differences in activity between individual leaves from normally developedand underdeveloped shoots only became apparent in the third week after véraison, it seemed as if the leaf area pershoot played a more important role than the photosynthetic output per unit leaf area in determining photosynthetatesupply to the rest of the vine up to this stage. From the third week after véraison, higher levels of photosynthetateswere produced by normally developed shoots than by underdeveloped shoots, due to the larger effective leaf areaper shoot as well as the higher photosynthetic activity per unit leaf area. This points to premature senescence of theleaves on underdeveloped shoots. The quantity and quality of the yield from normally developed shoots are expectedto benefit from the higher physiological output of the leaves. The enhancing effect on leaf functioning induced bycanopy exposure became apparent from the third week after véraison
The effects of peer influence on adolescent pedestrian road-crossing decisions
Objective: Adolescence is a high-risk period for pedestrian injury. It is also a time of heightened susceptibility to peer influence. The aim of this research was to examine the effects of peer influence on the pedestrian road-crossing decisions of adolescents.
Methods: Using 10 videos of road-crossing sites, 80 16- to 18-year-olds were asked to make pedestrian road-crossing decisions. Participants were assigned to one of 4 experimental conditions: negative peer (influencing unsafe decisions), positive peer (influencing cautious decisions), silent peer (who observed but did not comment), and no peer (the participant completed the task alone). Peers from the adolescentâs own friendship group were recruited to influence either an unsafe or a cautious decision.
Results: Statistically significant differences were found between peer conditions. Participants least often identified safe road-crossing
sites when accompanied by a negative peer and more frequently identified dangerous road-crossing sites when accompanied by a positive peer. Both cautious and unsafe comments from a peer influenced adolescent pedestriansâ decisions.
Conclusions: These findings showed that road-crossing decisions of adolescents were influenced by both unsafe and cautious comments from their peers. The discussion highlighted the role that peers can play in both increasing and reducing adolescent risk-taking
Shoot Heterogeneity Effects on Shiraz/Richter 99 Grapevines. III. Leaf Chlorophyll Content
In this study, the leaf chlorophyll content of normally developed and underdeveloped shoots was compared in anattempt to quantify the effect of shoot heterogeneity in a Shiraz/Richter 99 vineyard, located in the Stellenbosch areaof the Western Cape, South Africa. Comparisons are also made between normally developed and underdevelopedshoots from shaded and well-exposed canopies. No positive correlation was found between the photosyntheticactivity and the chlorophyll concentration of the leaves at five weeks after véraison. Equal amounts of chlorophyllper cm2 and a non-significant difference in the assimilation rate were calculated for the leaves of normally developedand underdeveloped shoots. No significant differences were found between the shaded and well-exposed canopies. Ittherefore appears that it is the effective surface area per leaf or per shoot rather than the chlorophyll concentrationor activity that may be responsible for any apparent difference in the photosynthetic output of the leaves fromnormally developed and underdeveloped shoots in shaded or well-exposed canopies
Submillimeter Imaging of NGC 891 with SHARC
The advent of submillimeter wavelength array cameras operating on large
ground-based telescopes is revolutionizing imaging at these wavelengths,
enabling high-resolution submillimeter surveys of dust emission in star-forming
regions and galaxies. Here we present a recent 350 micron image of the edge-on
galaxy NGC 891, which was obtained with the Submillimeter High Angular
Resolution Camera (SHARC) at the Caltech Submillimeter Observatory (CSO). We
find that high resolution submillimeter data is a vital complement to shorter
wavelength satellite data, which enables a reliable separation of the cold dust
component seen at millimeter wavelengths from the warmer component which
dominates the far-infrared (FIR) luminosity.Comment: 4 pages LaTeX, 2 EPS figures, with PASPconf.sty; to appear in
"Astrophysics with Infrared Surveys: A Prelude to SIRTF
Critical Casimir interaction of ellipsoidal colloids with a planar wall
Based on renormalization group concepts and explicit mean field calculations
we study the universal contribution to the effective force and torque acting on
an ellipsoidal colloidal particle which is dissolved in a critical fluid and is
close to a homogeneous planar substrate. At the same closest distance between
the substrate and the surface of the particle, the ellipsoidal particle prefers
an orientation parallel to the substrate and the magnitude of the fluctuation
induced force is larger than if the orientation of the particle is
perpendicular to the substrate. The sign of the critical torque acting on the
ellipsoidal particle depends on the type of boundary conditions for the order
parameter at the particle and substrate surfaces, and on the pivot with respect
to which the particle rotates
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