scholarly journals Retrospective analysis of the orbits of asteroids colliding with the Earth

Author(s):  
Konstantin S. Kholshevnikov ◽  
◽  
Ivan A. Balyaev ◽  
Leonid L. Sokolov ◽  
Boris B. Eskin ◽  
...  

In this paper, we consider the trajectories of real and model asteroids that lead to collisions with the Earth. They highlight the close approaches to the Earth that precede the impact. The presence of such approaches allows you to detect a dangerous object in advance, clarify its orbit, and also use the effect of a gravitational maneuver to economically prevent an asteroid from hitting the Earth. The article considers various families of collision trajectories: possible trajectories of real dangerous asteroids, as well as model ones trajectories that are not linked to a specific object. It is shown that in the first case, the approaches preceding the collision are noticeably greater.

2020 ◽  
pp. 4-13
Author(s):  
M.Ya. Maharramova ◽  
◽  
I.S. Guliyev ◽  
A.B. Huseynov ◽  
E.B. Zeynalov ◽  
...  

The paper deals with the review of the results of detection and analysis of fullerenes in natural objects. The fullerenes (generally, buckminsterfullerenes С60) were revealed in hard subsurface rocks and sedimentary deposits of Cretaceous-Paleogene, Perm and Pre-Cambrian stages of the Earth. The map of the Earth regions of fullerene exploration and the data on fullerene composition in the rocks is provided as well. The concepts of both biogenic and abiogenic fullerene origin are known. In the first case, the process of slow metamorphization of putrid mud and terrestrial crop took place under the impact of compressing and temperature, as a result of which various allotrope compounds of hydrocarbon dispersed in the mineral matrix were formed and accumulated. In the second case, the formation of fullerenes took place due to the shocking impact during thunderbolt or fireballs (Sudbury meteorite, carbonic chondritic meteorites) strikes on the rocks of earth surface, as well as global forest fires. For reliable fullerene identification in the samples of sedimentary and subsurface rocks should be used only physical-chemical methods of high definitions, such as laser desorption / ionization and electric-shocking mass-spectrometry. In the natural objects is predominantly revealed fullerene С60.Other types of fullerenes - C70, C74, C78, C84 and C100 are identified more rarely. A hypothesis on the composition of carbonic nanostructures in the rocks of mud volcanoes in the aspect of obtained information is developed.


1962 ◽  
Vol 14 ◽  
pp. 415-418
Author(s):  
K. P. Stanyukovich ◽  
V. A. Bronshten

The phenomena accompanying the impact of large meteorites on the surface of the Moon or of the Earth can be examined on the basis of the theory of explosive phenomena if we assume that, instead of an exploding meteorite moving inside the rock, we have an explosive charge (equivalent in energy), situated at a certain distance under the surface.


Author(s):  
Julie L. Wambaugh ◽  
Lydia Kallhoff ◽  
Christina Nessler

Purpose This study was designed to examine the association of dosage and effects of Sound Production Treatment (SPT) for acquired apraxia of speech. Method Treatment logs and probe data from 20 speakers with apraxia of speech and aphasia were submitted to a retrospective analysis. The number of treatment sessions and teaching episodes was examined relative to (a) change in articulation accuracy above baseline performance, (b) mastery of production, and (c) maintenance. The impact of practice schedule (SPT-Blocked vs. SPT-Random) was also examined. Results The average number of treatment sessions conducted prior to change was 5.4 for SPT-Blocked and 3.9 for SPT-Random. The mean number of teaching episodes preceding change was 334 for SPT-Blocked and 179 for SPT-Random. Mastery occurred within an average of 13.7 sessions (1,252 teaching episodes) and 12.4 sessions (1,082 teaching episodes) for SPT-Blocked and SPT-Random, respectively. Comparisons of dosage metric values across practice schedules did not reveal substantial differences. Significant negative correlations were found between follow-up probe performance and the dosage metrics. Conclusions Only a few treatment sessions were needed to achieve initial positive changes in articulation, with mastery occurring within 12–14 sessions for the majority of participants. Earlier occurrence of change or mastery was associated with better follow-up performance. Supplemental Material https://doi.org/10.23641/asha.12592190


2016 ◽  
Vol 22 ◽  
pp. 145-146
Author(s):  
Tiffany Schwasinger-Schmidt ◽  
Georges Elhomsy ◽  
Fanglong Dong ◽  
Bobbie Paull-Forney

2020 ◽  
Author(s):  
Ahmed Youssef Kada

BACKGROUND Covid-19 is an emerging infectious disease like viral zoonosis caused by new coronavirus SARS CoV 2. On December 31, 2019, Wuhan Municipal Health Commission in Hubei province (China) reported cases of pneumonia, the origin of which is a new coronavirus. Rapidly extendable around the world, the World Health Organization (WHO) declares it pandemic on March 11, 2020. This pandemic reaches Algeria on February 25, 2020, date on which the Algerian minister of health, announced the first case of Covid-19, a foreign citizen. From March 1, a cluster is formed in Blida and becomes the epicentre of the coronavirus epidemic in Algeria, its total quarantine is established on March 24, 2020, it will be smoothly alleviated on April 24. A therapeutic protocol based on hydroxychloroquine and azithromycin was put in place on March 23, for complicated cases, it was extended to all the cases confirmed on April 06. OBJECTIVE This study aimed to demonstrate the effectiveness of hydroxychloroquin/azithromycin protocol in Algeria, in particular after its extension to all patients diagnosed COVID-19 positive on RT-PCR test. We were able to illustrate this fact graphically, but not to prove it statistically because the design of our study, indeed in the 7 days which followed generalization of therapeutic protocol, case fatality rate decrease and doubling time increase, thus confirming the impact of wide and early prescription of hydroxychloroquin/azithromycin protocol. METHODS We have analyzed the data collected from press releases and follow-ups published daily by the Ministry of Health, we have studied the possible correlations of these data with certain events or decisions having a possible impact on their development, such as confinement at home and its reduction, the prescription of hydroxychloroquine/azithromycin combination for serious patients and its extension to all positive COVID subjects. Results are presented in graphics, the data collection was closed on 31/05/2020. RESULTS Covid-19 pandemic spreads from February 25, 2020, when a foreign citizen is tested positive, on March 1 a cluster is formed in the city of Blida where sixteen members of the same family are infected during a wedding party. Wilaya of Blida becomes the epicentre of coronavirus epidemic in Algeria and lockdown measures taken, while the number of national cases diagnosed begins to increases In any event, the association of early containment measures combined with a generalized initial treatment for all positive cases, whatever their degree of severity, will have contributed to a reduction in the fatality rate of COVID 19 and a slowing down of its doubling time. CONCLUSIONS In Algeria, the rapid combination of rigorous containment measure at home and early generalized treatment with hydroxychloroquin have demonstrated their effectiveness in terms of morbidity and mortality, the classic measures of social distancing and hygiene will make it possible to perpetuate these results by reducing viral transmission, the only unknown, the reopening procedure which can only be started after being surrounded by precautions aimed at ensuring the understanding of the population. CLINICALTRIAL Algeria, Covid-19, pandemic, hydroxychloroquin, azithromycin, case fatality rate


2021 ◽  
Vol 186 (Supplement_1) ◽  
pp. 502-505
Author(s):  
Justin J Stewart ◽  
Diane Flynn ◽  
Alana D Steffen ◽  
Dale Langford ◽  
Honor McQuinn ◽  
...  

ABSTRACT Introduction Soldiers are expected to deploy worldwide and must be medically ready in order to accomplish their mission. Soldiers unable to deploy for an extended period of time because of chronic pain or other conditions undergo an evaluation for medical retirement. A retrospective analysis of existing longitudinal data from an Interdisciplinary Pain Management Center (IPMC) was used to evaluate the temporal relationship between the time of initial duty restriction and referral for comprehensive pain care to being evaluated for medical retirement. Methods Patients were adults (>18 years old) and were cared for in an IPMC at least once between May 1, 2014 and February 28, 2018. A total of 1,764 patients were included in the final analysis. Logistic regression was used to evaluate the impact of duration between date of first duty restriction documentation and IPMC referral to the outcome variable of establishment of a permanent 3 (P3) profile. Results The duration between date of first duty restriction and IPMC referral showed a curvilinear relationship to probability of a P3 profile. According to our model, a longer duration before referral is associated with an increased probability of a subsequent P3 profile with the highest probability peaking at 19 months. The probability of P3 declines gradually for those who were referred later. Discussion This is the first time the relationship between time of initial duty restriction, referral to an IPMC, and subsequent P3 or higher profile has been tested. Future research is needed to examine medical conditions listed on the profile to see how they might contribute to the cause of referral to the IPMC. Conclusion A longer duration between initial duty restriction and referral to IPMC was associated with higher odds of subsequent P3 status for up to 19 months. Referral to an IPMC for comprehensive pain care early in the course of chronic pain conditions may reduce the likelihood of P3 profile and eventual medical retirement of soldiers.


Author(s):  
Pietro De Luca ◽  
Antonella Bisogno ◽  
Vito Colacurcio ◽  
Pasquale Marra ◽  
Claudia Cassandro ◽  
...  

Abstract Background Since the spreading of SARS-CoV-2 from China, all deferrable medical activities have been suspended, to redirect resources for the management of COVID patients. The goal of this retrospective study was to investigate the impact of COVID-19 on head and neck cancers’ diagnosis in our Academic Hospital. Methods A retrospective analysis of patients treated for head and neck cancers between March 12 and November 1, 2020 was carried out, and we compared these data with the diagnoses of the same periods of the 5 previous years. Results 47 patients were included in this study. We observed a significative reduction in comparison with the same period of the previous 5 years. Conclusions Our findings suggest that the COVID-19 pandemic is associated with a decrease in the number of new H&N cancers diagnoses, and a substantial diagnostic delay can be attributable to COVID-19 control measures.


2021 ◽  
Vol 287 ◽  
pp. 116547
Author(s):  
Sebastián García ◽  
Antonio Parejo ◽  
Enrique Personal ◽  
Juan Ignacio Guerrero ◽  
Félix Biscarri ◽  
...  

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