scholarly journals Parker Solar Probe Observations of a Dust Trail in the Orbit of 3200 Phaethon

2020 ◽  
Author(s):  
Karl Battams ◽  
Guillermo Stenborg ◽  
Russell Howard ◽  
Brendan Gallagher ◽  
Matthew Knight ◽  
...  
Keyword(s):  
White Light ◽  
Surface Brightness ◽  
Meteor Shower ◽  
Physical Parameters ◽  
Wide Field ◽  
Trail Following ◽  
Dust Trail ◽  
Visual Magnitude ◽  
Relationship Of ◽  
The Relationship

<p>We present details on the first white-light detection of a dust trail following the orbit of asteroid 3200 Phaethon, seen in images recorded by the Wide-field Imager for Parker Solar Probe (WISPR) instrument on the NASA Parker Solar Probe (PSP) mission. In this talk we will present a brief introduction to the PSP mission and the WISPR instrument. We will then show observations returned by WISPR in multiple perihelion 'encounters' that clearly show a diffuse dust trail perfectly aligned with the perihelion portion of the orbit of 3200 Phaethon, recorded while the asteroid itself was near aphelion. We will discuss the physical parameters that we have derived for the dust trail, including its visual magnitude, surface brightness and mass. We also speculate on the relationship of this trail to the Geminid meteor shower, of which Phaethon is assumed to be the parent, and demonstrate why the trail has not been detected visually until now, despite a number of dedicated observing campaigns. We also hope to present initial analyses of the most recent set of WISPR observations (January 2020), where we anticipate the trail should again be visible in the WISPR observations.</p>

scholarly journals The alignment of the axis of asymmetry in regenerating protoplasts of the moss, Ceratodon purpureus, is determined independently of axis polarity

Development ◽  
1996 ◽  
Vol 122 (1) ◽  
pp. 371-379 ◽  
Author(s):  
D.J. Cove ◽  
R.S. Quatrano ◽  
E. Hartmann
Keyword(s):  
White Light ◽  
Incident Light ◽  
Red Light ◽  
Opposite Polarity ◽  
Genetic Dissection ◽  
Axis Alignment ◽  
Directional Stimulus ◽  
Almost All ◽  
Relationship Of ◽  
The Relationship

Ceratodon protoplasts regenerate by polar outgrowth to form cell filaments. The kinetics of regeneration show that some cellular event has to be completed before regeneration can be initiated. The development of the regeneration axis is strongly influenced by light, with axis alignment and axis polarity being fixed independently. We define axis alignment as the relationship of the regeneration axis to the incident light, independent of polarity. Thus protoplasts regenerating directly towards, or directly away from the light source are defined as being similarly aligned but with opposite polarity. Protoplasts that regenerate in unidirectional red light form axes that are aligned parallel to the light direction, with about 70% being polarised towards the light and about 30% away. In unidirectional blue or white light, almost all protoplasts regenerate towards the light but axis alignment is determined less stringently. Re-orientation of protoplasts regenerating in unidirectional light shows that axis alignment is fixed between 8 and 9 hours before protoplasts regenerate and that axis polarity is fixed later. When protoplasts are removed from directional light to either non-directional light or to darkness, regeneration axes continue to be aligned by the earlier directional stimulus for at least 24 hours. Thus although axis alignment is fixed only about 8 hours before regeneration, in the absence of contradictory information about directionality in the light environment, protoplasts retain a memory of light direction for much longer. However, both reorientation and removal from a directional light field have profound effects on axis polarity; the pattern observed in undisturbed protoplasts being lost. To account for these observations, we propose that separate gradients are established independently to determine the alignment and polarity of the regeneration axis respectively. The alignment gradient is established rapidly and is steeper in red than in blue or white light, the polarity gradient is established slowly and is steeper in white or blue light than in red. These studies will now allow a genetic dissection of these processes in moss.

scholarly journals FORMATION OF MATHEMATICAL APPARATU FOR THE METHODOLOGY OF EMERGENCY PREVENTION ON SOLID WASTE LANDFILL WITH TECHNOLOGICAL EQUIPMENT

2020 ◽  
Vol 1 (154) ◽  
pp. 100-107 ◽  
Author(s):  
N. Rashkevich
Keyword(s):  
Mathematical Model ◽  
Solid Waste ◽  
Living Conditions ◽  
Analytical Dependence ◽  
Load Force ◽  
Physical Parameters ◽  
Technological Equipment ◽  
Waste Landfill ◽  
Relationship Of ◽  
The Relationship

The landfill with technological equipment becomes a clear danger of emergencies. The dangerous factors of emergencies there is landslides of waste mass, explosion of biogas on technological equipment. Modern scientific research aimed at establishing the laws of soil mechanics, obtaining the maximum amount of methane in the biogas composition, an unresolved part of the problem of ensuring civil security is the lack of an adequate method of emergency prevention. In the course of research, by the author was developed a mathematical model of emergency prevention on solid waste landfill with technological equipment. The mathematical model consists of an equation that describes the number of casualties due to an emergency and an equation that describes the existence of solutions to separate problems of estimating the conditions for determining the density, humidity, temperature of the waste mass. The desired solution of a separate problem is an analytical dependence that describes the relationship of the density of the waste mass in accordance with the variation of the physical parameters of the load force, porosity, height of waste storage. The desired solution of a separate problem is an analytical dependence that describes the relationship of the humidity of the waste mass in accordance with the variation of the input and visible fluid flows, density. The desired solution of a separate problem is an analytical dependence that describes the relationship of the temperature of the waste mass in accordance with the variation of the amount of heat supplied, generated, discharged. The number of people affected by an emergency is less than the objective level of the effects of the hazard, and the number of people with impaired living conditions is less than or equal to the objective level. Emergency prevention involves a set of measures aimed at preventing an increase in the number of victims, casualties, and persons with impaired living conditions from an object level to a higher level. Keywords: solid waste landfill, emergency, temperature, humidity, density.

Sinusitis in Status Asthmaticus

1994 ◽  
Vol 33 (12) ◽  
pp. 712-719 ◽  
Author(s):  
Catherine G. Fuller ◽  
Joyce J. Schoettler ◽  
Vicente Gilsanz ◽  
Marvin D. Nelson ◽  
Joseph A. Church ◽  
...  
Keyword(s):  
Otitis Media ◽  
Status Asthmaticus ◽  
Chronic Otitis Media ◽  
Clinical Findings ◽  
Physical Parameters ◽  
History Of ◽  
Physical Findings ◽  
Age Range ◽  
Relationship Of ◽  
The Relationship

The relationship between sinusitis and status asthmaticus (SA) remains obscure. The purposes of this study were to determine the prevalence of abnormal sinus radiographs (SXRs) and investigate possible risk factors among unselected children admitted with SA. Eighty-eight patients over 2 years of age (range 2 to 16 years) consecutively admitted with SA were studied. The principal investigator, blinded to SXR findings, interviewed and examined the patients with respect to 10 physical parameters and 14 historical parameters. Two staff radiologists, blinded to the clinical findings, interpreted the SXRs. Relationship of historical and physical findings with positive SXRs was determined by statistical analysis. Twenty-seven percent of patients were found to have abnormal SXRs, manifesting two thirds or greater opacification of the sinuses. The mean age, sex, and race of patients with abnormal SXRs was not significantly different from those with normal films. A history of two or more admissions per year for SA, and, in children under 5 years of age, a history of chronic otitis media, and the physical finding of otitis media were significantly more frequent among patients with abnormal SXRs. Although not found to be statistically significant, a history of sinusitis and cough occurred more frequently in association with abnormal SXRs.

The Relationship of Green-Line Transients to White-Light Coronal Mass Ejections

1997 ◽  
pp. 699-718
Author(s):  
S. P. Plunkett ◽  
G. E. Brueckner ◽  
K. P. Dere ◽  
R. A. Howard ◽  
M. J. Koomen ◽  
...  
Keyword(s):  
White Light ◽  
Coronal Mass Ejections ◽  
Green Line ◽  
Relationship Of ◽  
The Relationship

Scaling of Perceived Optical Distortion

1980 ◽  
Vol 24 (1) ◽  
pp. 622-625
Author(s):  
Frank E. Ward ◽  
Daniel F. Quinn
Keyword(s):  
Sine Wave ◽  
Physical Parameters ◽  
Physical Stimulus ◽  
Dissimilarity Index ◽  
Stimulus Attribute ◽  
Scaling Procedure ◽  
Psychological Scales ◽  
Third Dimension ◽  
Relationship Of ◽  
The Relationship

When observers make subjective judgments about a physical stimulus attribute, one is studying the relationship between physical and psychological scales. If the physical stimulus is clearly multidimensional, the relationship of the physical and psychological scales is not always obvious. We have carried out two studies to explore scaling of patterns that simulate optically induced visual distortions. In the first study, subjects rank-ordered computer generated sine wave patterns in order of distortion severity. The rankings corresponded to the physical parameters of frequency and amplitude. In the second study, all possible pairs of 48 stimuli were rated on a dissimilarity index. The data were analyzed by a non-metric multidimensional scaling procedure. We found that a third dimension, in addition to frequency and amplitude was necessary to adequately describe the data.

scholarly journals Widefield imaging of retinal and choroidal tumors

2019 ◽  
Vol 5 (S1) ◽  
Author(s):  
Natalia F. Callaway ◽  
Prithvi Mruthyunjaya
Keyword(s):  
Fundus Autofluorescence ◽  
Imaging Modalities ◽  
Fundus Photography ◽  
Wide Field ◽  
Indocyanine Angiography ◽  
Relationship Of ◽  
The Relationship ◽  
Field Imaging ◽  
Wide Field Imaging ◽  
Sd Oct

Abstract Background Wide-field imaging plays an increasingly important role in ocular oncology clinics. The purpose of this review is to describe the commonly used wide-field imaging devices and review conditions seen in ocular oncology clinic that underwent wide-field imaging as part of the multimodal evaluation. Summary of review Wide-field or wide-angle imaging is defined as greater than 50° field of view. Modern devices can reach far beyond this reporting fields of view up to 267°, when utilizing montage features, with increasingly impressive resolution. Wide-field imaging modalities include fundus photography, fluorescein angiography (FA), fundus autofluorescence (FAF), indocyanine angiography (ICG), spectral domain optical coherence tomography (SD-OCT), and recently wide-field OCT Angiography (OCTA). These imaging modalities are increasingly prevalent in practice. The wide-field systems include laser, optical, and lens based systems that are contact or non-contact lens systems each with its own benefits and drawbacks. The purpose of this review is to discuss commonly used wide-field imaging modalities for retinal and choroidal tumors and demonstrate the use of various widefield imaging modalities in select ocular oncology cases. Conclusions Clinical examination remains the gold standard for the evaluation of choroidal and retinal tumors. Wide-field imaging plays an important role in ocular oncology for initial documentation, surgical planning, determining the relationship of the tumor to adjacent ocular structures, following tumor size after treatment, and monitoring for recurrence.

Roadway-Vehicle Interaction, Physical Indexes, and Human Judgment of Ride Quality

1997 ◽  
Vol 1570 (1) ◽  
pp. 55-59 ◽  
Author(s):  
Chiu Liu ◽  
Robert Herman
Keyword(s):  
Ride Quality ◽  
Physical Parameters ◽  
Human Judgment ◽  
International Roughness Index ◽  
Moving Vehicle ◽  
Roughness Index ◽  
Static Profile ◽  
Relationship Of ◽  
The Relationship ◽  
Analytical Expressions

Present serviceability index (PSI) modeling has been an important subject for decades. Other dynamic indexes characterizing a roadway such as the international roughness index (IRI), averaged rectified slope (ARS), and averaged rectified speed (ARV) have been proposed and studied. However, the roles played by these indexes in the interaction between road, vehicle, and human ratings have not been made clear. A unified physical model linking the static profile of a roadway and the dynamic response of a vehicle to the profile to the serviceability index of the roadway is presented here. Analytical expressions for jerk index, acceleration index, ARV, ARS, and IRI are derived from the developed model in terms of the physical parameters for roadways and the dynamic characteristics of a vehicle. Then a linear relation between the PSI and the logarithm of the jerk index is proposed. Using the jerk index computed from field profile data, the linear functional form for the PSI is verified, and regression R2 values higher than 0.94 are obtained for various types of pavements. The same analysis is performed for other dynamic indexes, and the R2 values are found to be approximately in the range from 0.70 to 0.80. These results indicate that the theoretical model correctly predicts and explains the human rating of ride quality and that the jerk experienced by raters in a moving vehicle dictates the ratings. Moreover, the relationship of the static parameters of roadway profiles with human ratings is discussed using the conventional approach.

The relationship of the scleractinian corals to the rugose corals

Paleobiology ◽  
1980 ◽  
Vol 6 (02) ◽  
pp. 146-160 ◽  
Author(s):  
William A. Oliver
Keyword(s):  
Critical Points ◽  
Scleractinian Corals ◽  
Convincing Evidence ◽  
Early Triassic ◽  
Rugose Corals ◽  
History Of ◽  
The Subject ◽  
Relationship Of ◽  
The Relationship ◽  
Biologic Factors

The Mesozoic-Cenozoic coral Order Scleractinia has been suggested to have originated or evolved (1) by direct descent from the Paleozoic Order Rugosa or (2) by the development of a skeleton in members of one of the anemone groups that probably have existed throughout Phanerozoic time. In spite of much work on the subject, advocates of the direct descent hypothesis have failed to find convincing evidence of this relationship. Critical points are:(1) Rugosan septal insertion is serial; Scleractinian insertion is cyclic; no intermediate stages have been demonstrated. Apparent intermediates are Scleractinia having bilateral cyclic insertion or teratological Rugosa.(2) There is convincing evidence that the skeletons of many Rugosa were calcitic and none are known to be or to have been aragonitic. In contrast, the skeletons of all living Scleractinia are aragonitic and there is evidence that fossil Scleractinia were aragonitic also. The mineralogic difference is almost certainly due to intrinsic biologic factors.(3) No early Triassic corals of either group are known. This fact is not compelling (by itself) but is important in connection with points 1 and 2, because, given direct descent, both changes took place during this only stage in the history of the two groups in which there are no known corals.

Skeletal elements of crinoid echinoderms: High-resolution structural and microanalytical results

1983 ◽  
Vol 41 ◽  
pp. 194-195
Author(s):  
D. F. Blake ◽  
L. F. Allard ◽  
D. R. Peacor
Keyword(s):  
High Resolution ◽  
Marine Invertebrates ◽  
Sea Urchins ◽  
Structural Features ◽  
Sea Stars ◽  
High Resolution Tem ◽  
Relationship Of ◽  
The Relationship ◽  
Insight Into

Echinodermata is a phylum of marine invertebrates which has been extant since Cambrian time (c.a. 500 m.y. before the present). Modern examples of echinoderms include sea urchins, sea stars, and sea lilies (crinoids). The endoskeletons of echinoderms are composed of plates or ossicles (Fig. 1) which are with few exceptions, porous, single crystals of high-magnesian calcite. Despite their single crystal nature, fracture surfaces do not exhibit the near-perfect {10.4} cleavage characteristic of inorganic calcite. This paradoxical mix of biogenic and inorganic features has prompted much recent work on echinoderm skeletal crystallography. Furthermore, fossil echinoderm hard parts comprise a volumetrically significant portion of some marine limestones sequences. The ultrastructural and microchemical characterization of modern skeletal material should lend insight into: 1). The nature of the biogenic processes involved, for example, the relationship of Mg heterogeneity to morphological and structural features in modern echinoderm material, and 2). The nature of the diagenetic changes undergone by their ancient, fossilized counterparts. In this study, high resolution TEM (HRTEM), high voltage TEM (HVTEM), and STEM microanalysis are used to characterize tha ultrastructural and microchemical composition of skeletal elements of the modern crinoid Neocrinus blakei.

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