Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 14 de 14
Filtrar
Más filtros










Base de datos
Intervalo de año de publicación
1.
Astrobiology ; 17(6-7): 585-594, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-28731818

RESUMEN

This overview presents the physical principles, design, measurement capabilities, and summary of planned operations of the autonomous detector of radiation of neutrons onboard rover at Mars (ADRON-RM) on the surface of Mars. ADRON-RM is a Russian project selected for the joint European Space Agency-Roscosmos ExoMars 2020 landing mission. A compact passive neutron spectrometer, ADRON-RM, was designed to study the abundance and distribution of water and neutron absorption elements (such as Cl, Fe, and others) in the martian subsurface along the path of the ExoMars rover. Key Words: Mars exploration-Surface-Neutron Spectroscopy-Water. Astrobiology 17, 585-594.

2.
Rev Sci Instrum ; 87(8): 085112, 2016 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-27587165

RESUMEN

The recent availability of large volume cerium bromide crystals raises the possibility of substantially improving gamma-ray spectrometer limiting flux sensitivities over current systems based on the lanthanum tri-halides, e.g., lanthanum bromide and lanthanum chloride, especially for remote sensing, low-level counting applications or any type of measurement characterized by poor signal to noise ratios. The Russian Space Research Institute has developed and manufactured a highly sensitive gamma-ray spectrometer for remote sensing observations of the planet Mercury from the Mercury Polar Orbiter (MPO), which forms part of ESA's BepiColombo mission. The Flight Model (FM) gamma-ray spectrometer is based on a 3-in. single crystal of LaBr3(Ce(3+)) produced in a separate crystal development programme specifically for this mission. During the spectrometers development, manufacturing, and qualification phases, large crystals of CeBr3 became available in a subsequent phase of the same crystal development programme. Consequently, the Flight Spare Model (FSM) gamma-ray spectrometer was retrofitted with a 3-in. CeBr3 crystal and qualified for space. Except for the crystals, the two systems are essentially identical. In this paper, we report on a comparative assessment of the two systems, in terms of their respective spectral properties, as well as their suitability for use in planetary mission with respect to radiation tolerance and their propensity for activation. We also contrast their performance with a Ge detector representative of that flown on MESSENGER and show that: (a) both LaBr3(Ce(3+)) and CeBr3 provide superior detection systems over HPGe in the context of minimally resourced spacecraft and (b) CeBr3 is a more attractive system than LaBr3(Ce(3+)) in terms of sensitivities at lower gamma fluxes. Based on the tests, the FM has now been replaced by the FSM on the BepiColombo spacecraft. Thus, CeBr3 now forms the central gamma-ray detection element on the MPO spacecraft.

3.
Parazitologiia ; 48(6): 454-60, 2014.
Artículo en Ruso | MEDLINE | ID: mdl-25936171

RESUMEN

Based on the forest woody species wilt areassurvey in Nizhniy Novgorod region in August 2014, the possible factors of the pest spread risk modelling were analysed on six species of the genus Bursaphelenchus and Devibursaphelenchus teratospicularis using six parameters: plant host species, beetle vector species, average temperatures in July and January, annual precipitation. It was concluded that these parameters in the evaluated wilt spots correspond to climatic and biological data of the already published woody plants wilt records in Europe and Asia caused by the same nematode pest species. It was speculated that the annual precipitation of 600 mm and average July temperature of 25 degrees C or higher, are the critical combination that may be used to develop the predicative risk modelling in the forests' and parks' wilt monitoring.


Asunto(s)
Modelos Estadísticos , Pinus/parasitología , Enfermedades de las Plantas/parasitología , Rabdítidos/fisiología , Tylenchida/fisiología , Madera/parasitología , Animales , Escarabajos/parasitología , Insectos Vectores/parasitología , Lluvia , Rabdítidos/patogenicidad , Federación de Rusia , Estaciones del Año , Temperatura , Tylenchida/patogenicidad
4.
Science ; 330(6003): 483-6, 2010 Oct 22.
Artículo en Inglés | MEDLINE | ID: mdl-20966247

RESUMEN

Hydrogen has been inferred to occur in enhanced concentrations within permanently shadowed regions and, hence, the coldest areas of the lunar poles. The Lunar Crater Observation and Sensing Satellite (LCROSS) mission was designed to detect hydrogen-bearing volatiles directly. Neutron flux measurements of the Moon's south polar region from the Lunar Exploration Neutron Detector (LEND) on the Lunar Reconnaissance Orbiter (LRO) spacecraft were used to select the optimal impact site for LCROSS. LEND data show several regions where the epithermal neutron flux from the surface is suppressed, which is indicative of enhanced hydrogen content. These regions are not spatially coincident with permanently shadowed regions of the Moon. The LCROSS impact site inside the Cabeus crater demonstrates the highest hydrogen concentration in the lunar south polar region, corresponding to an estimated content of 0.5 to 4.0% water ice by weight, depending on the thickness of any overlying dry regolith layer. The distribution of hydrogen across the region is consistent with buried water ice from cometary impacts, hydrogen implantation from the solar wind, and/or other as yet unknown sources.


Asunto(s)
Luna , Medio Ambiente Extraterrestre , Hidrógeno , Análisis Espectral
5.
Astrobiology ; 8(4): 793-804, 2008 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-18844457

RESUMEN

The scientific objectives of neutron mapping of the Moon are presented as 3 investigation tasks of NASA's Lunar Reconnaissance Orbiter mission. Two tasks focus on mapping hydrogen content over the entire Moon and on testing the presence of water-ice deposits at the bottom of permanently shadowed craters at the lunar poles. The third task corresponds to the determination of neutron contribution to the total radiation dose at an altitude of 50 km above the Moon. We show that the Lunar Exploration Neutron Detector (LEND) will be capable of carrying out all 3 investigations. The design concept of LEND is presented together with results of numerical simulations of the instrument's sensitivity for hydrogen detection. The sensitivity of LEND is shown to be characterized by a hydrogen detection limit of about 100 ppm for a polar reference area with a radius of 5 km. If the presence of ice deposits in polar "cold traps" is confirmed, a unique record of many millions of years of lunar history would be obtained, by which the history of lunar impacts could be discerned from the layers of water ice and dust. Future applications of a LEND-type instrument for Mars orbital observations are also discussed.


Asunto(s)
Luna , Neutrones , Frío , Diseño de Equipo , Medio Ambiente Extraterrestre , Hidrógeno , Hielo , Modelos Teóricos , Vuelo Espacial/instrumentación , Nave Espacial/instrumentación , Estados Unidos , United States National Aeronautics and Space Administration
6.
Astrobiology ; 8(3): 605-12, 2008 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-18598140

RESUMEN

We present a summary of the physical principles and design of the Dynamic Albedo of Neutrons (DAN) instrument onboard NASA's 2009 Mars Science Laboratory (MSL) mission. The DAN instrument will use the method of neutron-neutron activation analysis in a space application to study the abundance and depth distribution of water in the martian subsurface along the path of the MSL rover.


Asunto(s)
Laboratorios , Marte , Neutrones , Vuelo Espacial/instrumentación , United States National Aeronautics and Space Administration , Hidrógeno/análisis , Análisis Numérico Asistido por Computador , Suelo/análisis , Estados Unidos
7.
Vestn Dermatol Venerol ; (7): 51-4, 1990.
Artículo en Ruso | MEDLINE | ID: mdl-2147805

RESUMEN

Mycoses of the hairy part of the head have been effectively treated in the two last decades in Armenia. The number of trichophytosis patients has reduced from 32.7 per 100,000 in 1965 to 5.4 per 100,000 in 1987. The share of anthroponotic trichophytosis among all trichophytosis forms has reduced from 24.9 to 6.7 percent. Chronic trichophytosis became quite rare among adult patients. Favus has not been recorded in Armenia since 1976. Epidemic outbreaks of imported anthroponotic microsporosis were recorded in the 60s and 70s. The incidence of zooanthroponotic microsporosis was low and the cases were imported. In recent years cases of human infection from mongrel cats were recorded in Armenia.


Asunto(s)
Dermatomicosis/epidemiología , Microsporum , Tiña Favosa/epidemiología , Tiña/epidemiología , Factores de Edad , Animales , Armenia/epidemiología , Dermatomicosis/transmisión , Brotes de Enfermedades/estadística & datos numéricos , Humanos , Prevalencia , Tiña/transmisión , Tiña del Cuero Cabelludo/epidemiología , Tiña del Cuero Cabelludo/transmisión , Tiña Favosa/transmisión , Zoonosis/transmisión
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA