Radiation exposure from heavy nuclei in solar particle beams in space systems of low shielding.
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Humans↗
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Results for “Solar System”
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[Effect of solar activity on the blood system (review of the literature)].
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Blood Cell Count↗
[Changes in medical indicators during heliogeophysical disturbances].
Influence of heliogeophysical factors on medical indexes is studied. Relationship between changes of these indexes and solar flares, magnetic and ionospheric storms is analyzed. Possibility of forecasting the biotropic effects by using the starting of heliogeophysical events as predictions is showed. Comparisons between calculations and experimental data are provided. Reasonable agreement was obtained.
Electromagnetic Fields↗
[The logic of a traditional health belief: solar eclipse and pregnancy in Ocuituco, Mexico].
An analysis of the logic of one of the commonest health beliefs in rural areas of Mexico is made, taking as a starting point testimonies collected in the area of Ocuituco, in the state of Morelos. This belief suggests that a pregnant woman is in danger of having a harelipped baby during a solar eclipse. The importance of the knowledge about the logic of this kind of beliefs is discussed from a public health perspective. These beliefs are associated with specific forms of suffering and give way to particular preventive measures which must be taken into account if the efficacy of health programs is to be increased. The interrelation of these beliefs with other traditional elements (such as the "loss of the shadow" and the "hot-cold theory") is discussed. Also, some of the already existing interpretations of this belief which seek to link the "loss of the shadow" with the solar eclipse belief are reviewed. Finally, an alternative interpretation of this belief is made from a structuralist methodological perspective. This interpretation is grounded in the Nahuatl myth on the creation of the sun and the moon, and in an analysis of the nature of rabbits in the Nahuatl culture, according to historic secondary sources. It is suggested that the belief about the danger of a solar eclipse must be interpreted in connection to the "hot-cold theory", but not to the "loss of the shadow". This paper concludes by emphasizing the importance of this type of research within the public health field, as it enables us both to understand the underlying logic of this type of conceptions, and to reinforce the dialogue between modern and alternative medicine, so that the daily encounter between these two types of medicine can be facilitated.
Cleft Lip↗
[Biomedical effects of solar activity].
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Adolescent↗
Sun compass-based spatial learning impaired in homing pigeons with hippocampal lesions.
The hippocampal formation is known to be critical for spatial cognition, for example, regulating the learning of environmental maps. But how is a spatial map learned, and what is the role of the hippocampal formation in the learning process? The sun compass is perhaps the most ubiquitous, naturally occurring spatial orientation mechanism found in the animal kingdom. The sun compass may also serve as a directional reference that supports spatial learning. We report that homing pigeons with hippocampal lesions were unable to use the sun compass to learn the directional location of food in an outdoor, experimental arena. Homing pigeons with lesions of the caudal neostriatum readily learned the same task, and showed appropriately shifted directional responses following a clock-shift manipulation demonstrating that they were indeed using the sun compass to learn the task. Finally, both hippocampal and control lesioned birds quickly learned a procedurally similar task where a color cue identified the location of food in the same experimental arena. The results indicate that hippocampal lesions impair sun compass use in the context of learning. As such, the results support the hypothesis that the importance of the hippocampal formation in spatial cognition may be related to its participation in a neural process in which information from a directional reference, in this case the sun compass, is used to learn the directional relationship among stimuli in space.
Animals↗
[Animal behavior against a background of long period heliogeophysical fluctuations].
Many Earth biological processes are immediately linked with the Cosmos, its matter and energy. Cosmic rays, which as noted by V.I. Vernadsky, come from all heavenly bodies, penetrate the whole Earth and everything on it. It is solar rays that dictate the main features of the planetary organisation of the biosphere, provide the free chemical energy, and determine the development of the organic world, cycles, rhythms and the great variety of this development.
Animals↗
Correlation of human longevity oscillations with sunspot cycles.
An examination of past human mortality trends revealed that the mean longevity of birth cohorts from 1740 to 1900 for United States of America (U.S.) Congressional Representatives exhibited oscillations that coincided with the 9- to 12-year sunspot cycle. Cohort mean longevities were 2-3 years greater during times of low sunspot activity than at peak activity. This phenomenon was confirmed in data from members of the House of Commons of the United Kingdom Parliament and from University of Cambridge alumni. An additional longevity oscillation with a longer period was visible in the data and may also be related to sunspot cycles. The amplitude and frequency modulations in the longevity and sunspot oscillations aligned when a 20-year phase shift was incorporated. This shift requires the existence of a lag between solar changes and the affected birth cohorts. Several possible causes of the effect are discussed, in particular: radiation on primordial germ cells in developing embryos; influenza epidemics and pandemics; and weather. The size of the longevity oscillation requires that the solar effect must be considered in studies that examine longevity trends and risk estimation.
History, 18th Century↗
Characterization of Anopheles pseudopunctipennis larval habitats.
A survey of Anopheles pseudopunctipennis larval habitats was performed throughout most of its known geographic range. Eleven key environment variables characterized most larval habitats of this important vector of malaria in the Americas. Larval habitats occurred mainly in valley and foothill areas which were often situated in arid regions. Immatures were found primarily during the dry season in sun-exposed freshwater stream pools with clear, shallow, stagnant water containing abundant filamentous green algae and/or aquatic vegetation.
Animals↗
The origin of low mass stars.
Recent evidence indicates that most low mass stars in the Galaxy (< 5 M [symbol: see text]) form alongside massive stars in clusters embedded in giant molecular clouds. Once their parental gas is removed, the fate of these clusters is to disperse and blend into the field population of the galactic disk. The distribution of stellar masses in the solar neighborhood, called the Initial Mass Function, is discussed in the context of the origin of low mass stars. Arguments based on the production rate of field stars are presented that point to giant molecular clouds as the primary birth sites for low mass stars. The role of observations of molecular clouds at millimeter and infrared wavelengths in confirming this picture is reviewed. Millimeter-wave observations have revealed that molecular clouds consist of low-density gas interspersed with high-density cores. Near-infrared images of these clouds indicate that stars form preferentially in these cores, with the number of young stars roughly scaling with the mass of the core. Molecular-line and near-infrared observations which characterize star formation in the nearest giant molecular cloud complex in Orion are presented. The implications for the Sun forming in a cluster environment are briefly discussed.
Astronomical Phenomena↗
Habitable zones around low mass stars and the search for extraterrestrial life.
Habitable planets are likely to exist around stars not too different from the Sun if current theories about terrestrial climate evolution are correct. Some of these planets may have evolved life, and some of the inhabited planets may have evolved O2-rich atmospheres. Such atmospheres could be detected spectroscopically on planets around nearby stars using a space-based interferometer to search for the 9.6 micron band of O3. Planets with O2-rich atmospheres that lie within the habitable zone around their parent star are, in all probability, inhabited.
Astronomical Phenomena↗
Backup compass mechanisms in pigeon orientation with the sun in the zenith.
The sun is known to guide homing pigeons as a priority cue. The literature indicates that under total overcast conditions pigeons rely on a backup mechanism akin to the magnetic inclination compass for which there is much laboratory evidence in migratory birds. Total overcast conditions are not favorable for orientation research in the State of São Paulo, Brazil. The orientation of homing pigeons raised near the tropic of Capricorn was therefore observed around the time of the December solstice, when the sun culminated directly overhead, with a consequent interruption of the sun compass for a short time every day. In these experiments, carried out between 1981 and 1993, local geomagnetic field inclination was -25 degrees to -29 degrees 30', so that a functioning magnetic inclination compass should have been available to the birds. Whereas the birds released with sun to zenith angles between 10 degrees and 30 degrees were well oriented, both in the morning (99 vanishing bearings) and in the afternoon (143 vanishing bearings), those released with the sun less than 5 degrees away from the zenith showed random orientation (105 vanishing bearings), with no evidence of an alternative magnetic compass mechanism.
Animals↗
The radiation environment in low-Earth orbit.
The radiation environment in low-Earth orbit is a complex mixture of galactic cosmic radiation, particles of trapped belts and secondary particles generated in both the spacecraft and Earth's atmosphere. Infrequently, solar energetic particles are injected into the Earth's magnetosphere and can penetrate into low-Earth orbiting spacecraft. In this paper, the sources of charged-particle radiation that contribute significantly to radiation exposure on manned spacecraft are reviewed briefly, and estimates of expected dose rate for the upcoming International Space Station that are based on measurements made on the Russian Mir orbital station are provided.
Aerospace Medicine↗
[Natural environment of ions in air].
The author discusses the effect of natural changes in atmospheric parameters on the environment of air-ions. The investigations show that the position of the Sun is the major factor which changes the environment. A significant effect of plant agglomerations on the concentration of air-ions was also observed.
Air Ionization↗
The shadow rule: a simple method for sun protection.
The intensity of ultraviolet radiation (UVR) from the sun is directly related to the angle of the sun or altitude above the horizon. Solar altitude at any given clock time varies with season and latitude-longitude. The shadow rule indirectly determines the sun's altitude by observing the length of a person's shadow during the time course of a day. When the shadow on a horizontal surface in the sun is equal in length to height of the person casting the shadow, then the altitude of the sun above the horizon is 45 degrees. The tangent of 45 degrees altitude (tan alt) equals 1 or the ratio of the height of the person casting a shadow (y) to the length of the person's shadow (x). In middle latitudes, the intensity of UVR is approximately inversely proportional to the length of the person's shadow. Thus, when a person's shadow is shorter than the person is tall, the intensity of UVR from the sun is more likely to cause sunburn.
Altitude↗
[Solar retinopathy].
The purpose of this study is the present clinical evaluation of 21 patients (number of affected eyes--33), who watched eclipse of the sun on 12 October 1996. All patients had general ophthalmic examination with emphasis on visual acuity, visual field, Amsler test, fluorescein angiography and fundus appearance. Eleven out of 21 patients had at least one follow up examination (number of affected eyes--17). None of the patient received any treatment. All patients revealed tiny, central scotomata--positive Amsler test and decreased visual acuity on the first visit; reading Snellen chart could be improved in all patients by adequate head tilt or eye movement (improvement up to 3 Snellen chart lines). No signs of retinopathy were observed in two eyes with uncorrected refractive error and one amblyopic eye. After 7-8 weeks the visual acuity was decreased to 5/30 in two eyes and to 5/10 in ten eyes. In all those eyes persisted a tiny, central scotoma. Looking at the eclipse of the sun in spite of using primitive eye protection may cause irreversible retinal damage. Return of visual acuity to 5/5 does not always imply complete recovery because of persistent central scotoma.
Adolescent↗
Oxygen reservoirs in the early solar nebula inferred from an Allende CAI.
Ultraviolet laser microprobe analyses of a calcium-aluminum-rich inclusion (CAI) from the Allende meteorite suggest that a line with a slope of exactly 1.00 on a plot of delta (17)O against delta (18)O represents the primitive oxygen isotope reservoir of the early solar nebula. Most meteorites are enriched in (17)O and (18)O relative to this line, and their oxygen isotope ratios can be explained by mass fractionation or isotope exchange initiating from the primitive reservoir. These data establish a link between the oxygen isotopic composition of the abundant ordinary chondrites and the primitive (16)O-rich component of CAIs.
Meteoroids↗
Oxygen isotope exchange between refractory inclusion in Allende and solar nebula gas.
A calcium-aluminum-rich inclusion (CAI) from the Allende meteorite was analyzed and found to contain melilite crystals with extreme oxygen-isotope composition (approximately 5 percent oxygen-16 enrichment relative to terrestrial oxygen-16). Some of the melilite is also anomalously enriched in oxygen-16 compared with oxygen isotopes measured in other CAIs. The oxygen isotopic variation measured among the minerals (melilite, spinel, and fassaite) indicates that crystallization of the CAI started from oxygen-16-rich materials that were probably liquid droplets in the solar nebula, and oxygen isotope exchange with the surrounding oxygen-16-poor nebular gas progressed through the crystallization of the CAI. Additional oxygen isotope exchange also occurred during subsequent reheating events in the solar nebula.
Crystallization↗