Dust Storms in Space?

1971 ◽  
Vol 13 ◽  
pp. 223-226
Author(s):  
Robert G. Roosen ◽  
Otto E. Berg ◽  
Neil H. Farlow
Keyword(s):  
Dust Storms ◽  
Dust Particles ◽  
Sounding Rocket ◽  
List Type ◽  
Small Particles ◽  
Negative Results ◽  
The Earth ◽  
Short Period ◽  
Impact Data ◽  
Rule Out

Silverberg (1970) has explained the “dust storms” observed by the early satellite-borne microphone detectors by postulating that the orbital planes of short-period, low-inclination comets are filled with micrometeoroids. We report here on three separate approaches to test the validity of this hypothesis. (1)Optical scans of the Gegenschein brightness can yield no useful information on the nearly isotropic sheets of dust predicted by Silverberg.(2)An attempt to directly collect dust particles during a predicted high flux period by means of a sounding rocket yielded negative results.(3)Over three years of particle impact data from extremely sensitive detectors flown aboard Pioneers 8 and 9 show no observable dust storms.Hence Silverberg’s hypothesis appears untenable.However, we should not rule out the possibility that observable showers of very small particles can be blown directly off the nuclei of some comets passing between the Earth and the Sun.

The Origin of the Moon and its Relationship to the Origin of the Solar System

1962 ◽  
Vol 14 ◽  
pp. 133-148 ◽  
Author(s):  
Harold C. Urey
Keyword(s):  
Solar System ◽  
The Moon ◽  
The Past ◽  
The Earth ◽  
Short Period ◽  
Origin Of The Moon

During the last 10 years, the writer has presented evidence indicating that the Moon was captured by the Earth and that the large collisions with its surface occurred within a surprisingly short period of time. These observations have been a continuous preoccupation during the past years and some explanation that seemed physically possible and reasonably probable has been sought.

Discussion following the presentation by F. Deubner

1977 ◽  
Vol 36 ◽  
pp. 69-74
Keyword(s):  
List Type ◽  
The Sun ◽  
Type Number ◽  
Harmonic Motion ◽  
Locally Excited ◽  
Long Period ◽  
Coherent Wave ◽  
Short Period ◽  
Global Modes

The discussion was separated into 3 different topics according to the separation made by the reviewer between the different periods of waves observed in the sun :1) global modes (long period oscillations) with predominantly radial harmonic motion.2) modes with large coherent - wave systems but not necessarily global excitation (300 s oscillation).3) locally excited - short period waves.

Impairment Questions and Answers

1999 ◽  
Vol 4 (4) ◽  
pp. 4-4
Keyword(s):  
Symptom Validity ◽  
Validity Testing ◽  
Symptom Validity Testing ◽  
Negative Results ◽  
Tunnel Vision ◽  
Questions And Answers ◽  
Blurry Vision ◽  
Fatigue Evaluation ◽  
Choice Testing ◽  
Rule Out

Abstract Symptom validity testing, also known as forced-choice testing, is a way to assess the validity of sensory and memory deficits, including tactile anesthesias, paresthesias, blindness, color blindness, tunnel vision, blurry vision, and deafness—the common feature of which is a claimed inability to perceive or remember a sensory signal. Symptom validity testing comprises two elements: A specific ability is assessed by presenting a large number of items in a multiple-choice format, and then the examinee's performance is compared with the statistical likelihood of success based on chance alone. Scoring below a norm can be explained in many different ways (eg, fatigue, evaluation anxiety, limited intelligence, and so on), but scoring below the probabilities of chance alone most likely indicates deliberate deception. The positive predictive value of the symptom validity technique likely is quite high because there is no alternative explanation to deliberate distortion when performance is below the probability of chance. The sensitivity of this technique is not likely to be good because, as with a thermometer, positive findings indicate that a problem is present, but negative results do not rule out a problem. Although a compelling conclusion is that the examinee who scores below probabilities is deliberately motivated to perform poorly, malingering must be concluded from the total clinical context.

Bone Marrow Culture Yield for the Diagnosis of Opportunistic Diseases in Patients with AIDS and Disseminated Kaposi Sarcoma

2020 ◽  
Vol 18 (4) ◽  
pp. 277-282
Author(s):  
P. Cornejo-Juárez ◽  
B. Islas-Muñoz ◽  
A.F. Ramírez-Ibargüen ◽  
G. Rosales-Pedraza ◽  
B. Chávez-Mazari ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Complete Blood Count ◽  
Kaposi Sarcoma ◽  
Opportunistic Pathogens ◽  
Reactive Protein ◽  
Negative Results ◽  
Recent Diagnosis ◽  
Male Patients ◽  
Liver Tests ◽  
Rule Out

Background: Disseminated Kaposi sarcoma (DKS) is present in patients with advanced HIV infection in whom co-infection with other opportunistic pathogens can occur. Bone marrow (BM) aspirate and biopsy comprises a robust diagnostic tool in patients with fever, cytopenias, and abnormal liver tests. However, the yield in patients with DKS has not been determined. Objective: The aim of this study was to evaluate the utility of BM aspirate and biopsy in patients with DKS. Methods: We included 40 male patients with recent diagnosis of DKS. BM aspirate and biopsy was performed as part of the workup to rule out co-infections. Results: In four patients, Mycobacterium avium complex (MAC) was recovered from culture. In another four patients, intracellular yeasts were observed in the Grocott stain, diagnosed as Histoplasma. The yield of BM was calculated in 20%. Only 12 patients (30%) had fever and 11 (27.5%) had pancytopenia. Alkaline phosphatase (ALP) above normal values and C-reactive protein (CRP) were higher in patients with positive results for BM than in those with negative results (63% vs. 21.9%, and 3.0 vs. 1.2 mg/L; p = 0.03 in both comparisons). No differences were found on comparing complete blood-count abnormalities. Conclusion: We recommend performing a BM aspirate for stains, culture, and biopsy in all HIV patients with DKS, as this will permit the early diagnosis of co-infections and prevent further complications in those who receive chemotherapy.

scholarly journals New Tools for the Optimized Follow-Up of Imminent Impactors

Universe ◽  
2021 ◽  
Vol 7 (1) ◽  
pp. 10
Author(s):  
Maddalena Mochi ◽  
Giacomo Tommei
Keyword(s):  
Orbit Determination ◽  
Main Belt ◽  
Impact Monitoring ◽  
The Earth ◽  
Current Observation ◽  
Short Period ◽  
Fly Eye ◽  
Near Earth Asteroids ◽  
Near Earth Objects

The solar system is populated with, other than planets, a wide variety of minor bodies, the majority of which are represented by asteroids. Most of their orbits are comprised of those between Mars and Jupiter, thus forming a population named Main Belt. However, some asteroids can run on trajectories that come close to, or even intersect, the orbit of the Earth. These objects are known as Near Earth Asteroids (NEAs) or Near Earth Objects (NEOs) and may entail a risk of collision with our planet. Predicting the occurrence of such collisions as early as possible is the task of Impact Monitoring (IM). Dedicated algorithms are in charge of orbit determination and risk assessment for any detected NEO, but their efficiency is limited in cases in which the object has been observed for a short period of time, as is the case with newly discovered asteroids and, more worryingly, imminent impactors: objects due to hit the Earth, detected only a few days or hours in advance of impacts. This timespan might be too short to take any effective safety countermeasure. For this reason, a necessary improvement of current observation capabilities is underway through the construction of dedicated telescopes, e.g., the NEO Survey Telescope (NEOSTEL), also known as “Fly-Eye”. Thanks to these developments, the number of discovered NEOs and, consequently, imminent impactors detected per year, is expected to increase, thus requiring an improvement of the methods and algorithms used to handle such cases. In this paper we present two new tools, based on the Admissible Region (AR) concept, dedicated to the observers, aiming to facilitate the planning of follow-up observations of NEOs by rapidly assessing the possibility of them being imminent impactors and the remaining visibility time from any given station.

scholarly journals The new agroforestry paradigm’s formation

2019 ◽  
Vol 89 (10) ◽  
pp. 1044-1051
Author(s):  
Aleksandr S. Rulev ◽  
Anna M. Pugacheva
Keyword(s):  
Three Dimensional ◽  
Main Idea ◽  
Agroforestry Systems ◽  
Agricultural Landscapes ◽  
Dust Storms ◽  
Erosion Processes ◽  
Short Period ◽  
International Projects ◽  
Forest Belts ◽  
Protective Forest

From acceptance of the 1948 Plan of Field-Protective Afforestation to the present (2019), this article considers the new agroforestry paradigms protracted formation. Scientific achievements from the 1940s, introduced into practice, served as the basis for decisions on natures global transformation. Pilot facilities from the beginning of the 20th century (the Bogdinsky agroforestry stronghold, the Stone-steppe oasis) still serve as reference objects for agroforest reclamation of territories, with a scientific approach that allows them to function productively today. The plans main idea is to combat drought and desertification of steppe lands, erosion processes, and to prevent sand and dust storms. Creation of 5709 thousand hectares of protective forests, afforestation of 1106 thousand hectares of ravines, fixing and afforestation of sand on an area of 322 thousand hectares, and implementation of many planned activities during a short period locate this plan among other ambitious international projects. The authors draw attention to the time of creation and the volume of plantings of paramount importance, that is, state protective forest belts and protective forest plantations. Understanding the importance of agroforestry for modern agricultural landscapes led to formation of sustainable and durable agroforestry systems in subarid landscapes based on a combination of agricultural and landscape-ecological ideologies. Allegedly, considering terrain ecotopes, three-dimensional evaluation of the agrolandscape and a non-linear approach make it possible to create multifunctional, highly productive agroforestry systems in critical agriculture zones.

scholarly journals Gravitational differentiation in the regimes from stokes settling to Rayleigh–Raylor flows

2019 ◽  
pp. 15-30
Author(s):  
V. P. Trubitsyn
Keyword(s):  
Viscous Fluid ◽  
Interacting Particles ◽  
Small Particles ◽  
Continuous Transition ◽  
New Approach ◽  
Earth's Core ◽  
The Core ◽  
The Earth ◽  
Large Particles ◽  
Two Component

The Earth’s core was formed under gravitational differentiation in the course of the separation of iron and silicates. Most of the iron has gone into the core as early as when the Earth was growing. However, iron continued to precipitate even during the subsequent partial solidification which developed from the bottom upwards. At the different stages and in the different layers of the mantle, iron was deposited in different regimes. In this paper, the mechanisms of the deposition of a cloud of heavy interacting particles (or drops) in a viscous fluid are considered. A new approach suitable for analytical and numerical tracing the changes in the structure of the flows in a two-component suspension under continuous transition from the Stokessettling (for the case of a cloud of large particles) to the Rayleigh–Taylor flows and heavy diapirs (for the case of a cloud of small particles) is suggested. It is numerically and analytically shown that the both regimes are the different limiting cases of the sedimentation convection in suspensions.

scholarly journals Using satellite images in teaching geography at school

2020 ◽  
Keyword(s):  
Satellite Images ◽  
Visual Image ◽  
Dust Storms ◽  
Advantages And Disadvantages ◽  
The Earth ◽  
Atmospheric Fronts ◽  
History Of ◽  
Memory Representations ◽  
Control Knowledge

Satellite images occupy a signifi cant place in the Earth Sciences. This fully applies to geography. Images of the Earth from space are used in various activities: to assess crops, to establish the boundaries of a phenomenon, to determine the degree of contamination of land or ocean surfaces, to search for minerals, and so on. But in school geography, satellite images are used very rarely - for example, to prove the sphericity of the Earth or to show the view of each continent from space. The purpose of this article is to highlight the methods of using satellite images in geography lessons at school and to create tasks based on these means of training. Main material. The history of using satellite images in school geography has been considered in the article. Advantages and disadvantages of satellite images as training tools are also noted. The role of satellite images in the formation of geographical representations is highlighted by the authors. These images realistically depict many natural phenomena (atmospheric fronts, cyclones, dust storms, etc.). Therefore, as a means of visualization, they contribute to the formation of memory representations in schoolchildren. Examples of a number of satellite images show how they can be used in teaching geography. The article off ers a methodical way of the use of satellite images at diff erent stages of learning. These images can be used to explain the training material, repeat it, control knowledge, and so on. Satellite images can be used to solve cartographic tasks. As practice has shown, we can perform creative tasks based on images. Conclusions. Satellite images play an important role in the system of teaching geography. The use of satellite images allows us to improve the pupils’ interest in the subject. Satellite images form geographical memory representations create a visual image of the natural appearance of the Earth. The study of educational opportunities of the Earth’s images from space has revealed three groups of requirements: pedagogical, technical and specific, determined by the content of school geography. The teacher should select satellite images based on the content of educational tasks of school geography.

scholarly journals Preparation of Protein a Gold

1997 ◽  
Vol 5 (5) ◽  
pp. 12-13
Author(s):  
Paul Webster
Keyword(s):  
Electron Microscopy ◽  
Biological Activity ◽  
Colloidal Gold ◽  
Protein A ◽  
List Type ◽  
Type Number ◽  
Stained Glass ◽  
Small Particles ◽  
Silver Enhancement ◽  
Gold Particles

Colloidal gold has been used for centuries in the preparation of stained glass for windows and fine glassware. In recent years, colloidal gold particles have become a useful tool in microscopy for staining tissues and sections. Colloidal gold particles are especially useful for biological electron microscopy, Some of the reasons why are listed below.*Homogeneous preparations of particles varying in size from 3μm to 20μm can be easily prepared.*Colloidal gold suspensions are inexpensive to prepare. Most proteins can be easily coupled to colloidal gold particles.*Most proteins can be easily coupled to colloidal gold particles.*Proteins coupled to gold particles do not appear to lose their biological activity.*The colloidal gold particles can be easily seen in the electron microscope.*Colloidal gold does not naturally occur in biological material. Therefore, if you see it, it is because you put it there.*Colloidal gold probes can be used for light microscopy, The larger gold particles can be directly observed by the light microscope. Small particles are detected by silver enhancement or epipolarized illumination.*The same probes can be used for both LM and TEM imrnunocytochemistry.

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