Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Solar System”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 883 records · Page 49Linked to original sources
PubMed2001

Eclipse retinopathy.

PURPOSE: Solar retinopathy is a well-recognised clinical entity of macular damage caused by viewing the sun, induced by a photochemical process. The term 'eclipse retinopathy' is frequently employed when the condition is sustained as a result of viewing a solar eclipse. Considerable public excitement had been raised in anticipation of the full solar eclipse on 11 August 1999. Whilst experience has shown that visual morbidity is likely to be temporary, current evidence is anecdotal and restricted to isolated case reports and series. This study was conducted to establish the true visual morbidity associated with a solar eclipse, and whether it was temporary or permanent. METHODS: A 3 month active case ascertainment study was carried out from July to September 1999 to record cases presenting to ophthalmologists with visual symptoms arising from solar viewing. Further information about the cases was sought using a short questionnaire. A follow-up questionnaire requesting outcome data at 6 months was also employed. RESULTS: There were 70 reported cases of visual loss. The average age was 29.5 +/- 12.9 years. Half the cases presented to an ophthalmologist within 2 days of the eclipse. An abnormal macular appearance was reported in 84% of patients at presentation. There have been no reported cases of continued visual loss or symptoms at 6 months. CONCLUSIONS: This is the largest nationwide study of the visual effects of a solar eclipse ever undertaken. There were no recorded cases of permanent visual loss, which corroborates the previous evidence that visual morbidity is likely to be temporary. It would appear probable that public health education was most effective in reducing visual morbidity and hence keeping the consequent burden on the NHS to a minimum.

Adolescent↗
PubMed2005

A non-terrestrial 16O-rich isotopic composition for the protosolar nebula.

The discovery in primitive components of meteorites of large oxygen isotopic variations that could not be attributed to mass-dependent fractionation effects has raised a fundamental question: what is the composition of the protosolar gas from which the host grains formed? This composition is probably preserved in the outer layers of the Sun, but the resolution of astronomical spectroscopic measurements is still too poor to be useful for comparison with planetary material. Here we report a precise determination of the oxygen isotopic composition of the solar wind from particles implanted in the outer hundreds of nanometres of metallic grains in the lunar regolith. These layers of the grains are enriched in 16O by >20 +/- 4 per thousand relative to the Earth, Mars and bulk meteorites, which implies the existence in the solar accretion disk of reactions--as yet unknown--that were able to change the 17O/16O and 18O/16O ratios in a way that was not dependent strictly on the mass of the isotope. Photochemical self-shielding of the CO gas irradiated by ultraviolet light may be one of these key processes, because it depends on the abundance of the isotopes, rather than their masses.

Carbon Monoxide↗
PubMed2001

Save the earth.

Explore the source record for details and available documents.

Conservation of Natural Resources↗
PubMed2001

The ice of life.

Explore the source record for details and available documents.

Astronomical Phenomena↗
PubMed2001

Catching some sun.

Explore the source record for details and available documents.

Astronomical Phenomena↗
PubMed1994

The Earth's elements.

The elements that make up the earth and its inhabitants were created by earlier generations of stars.

Astronomical Phenomena↗
PubMed2002

Participation of the homing pigeon thalamofugal visual pathway in sun-compass associative learning.

The ascending thalamofugal visual pathway in pigeons (Columba livia) terminates in the telencephalic wulst. Characterizing the role of this pathway in visually guided behaviour has remained a challenge. To determine whether this pathway, and in particular the wulst, may participate in sun-compass-guided behaviour in homing pigeons, intact, ectostriatum-lesioned or wulst-lesioned pigeons were trained to use their sun compass to locate the direction of a food reward in an outdoor, octagonal arena. Control and ectostriatum-lesioned pigeons learned the task well, and orientated appropriately during the first trial of the last three training sessions and after a phase-shift manipulation. In contrast, the wulst-lesioned pigeons learned the task but they took more sessions to learn, and their directional choices were more scattered during the first trial of the last three training sessions and after the phase-shift manipulation. A subsequent regression analysis indicated that deeper layers of the wulst might have made more of a contribution to the observed behavioural impairments. The data indicate that the homing pigeon wulst participates in visually guided behaviour when the sun compass is used to learn the directional location of a goal.

Animals↗
PubMed2000

Effects of simulated solar disinfection of water on infectivity of Salmonella typhimurium.

To determine whether cells of Salmonella typhimurium rendered nonculturable by simulated solar disinfection retain infectivity for mice. Bacteria suspended in water were exposed to UVA irradiation for up to 8 h. Culturability, determined by colony forming unit and Most Probable Number counts, fell by six log10 units, while cellular activity determined by the Kogure cell elongation test was retained by approximately 5% of the cells present after 8 h. Intraperitoneal doses of nonculturable cells and active but nonculturable (ABNC) cells exceeding the LD50 of the test organism and BALB/c mouse host, respectively, by 4 and 3 orders of magnitude failed to produce detectable infections. Culturable cells that had been irradiated for 1.5 h were less infective (virulent) than their nonirradiated counterparts. Nonculturable and ABNC cells of Salm. typhimurium produced by UVA irradiation do not retain infectivity for mice. Although ABNC cells could be produced by low cost solar disinfection systems, they do not appear to pose a potential infection hazard.

Animals↗
PubMed1993

Risk from relativistic heavy ions on manned space missions.

The risk from exposure to radiation posed to space travelers outside the magnetic shielding provided by the geomagnetosphere will come from two sources: the slowly varying but low intensity high-energy galactic cosmic rays and the more intense predominantly low-energy protons from large solar particle events associated with magnetic disturbances originating sporadically on or within the solar surface during the active period of the 11-year solar cycle. The energy spectra of the protons in solar particle events are quite soft, with large numbers of low-energy protons and a rather steep decrease of the energy spectra with increasing energy. This allows for the possibility to provide, within the space vehicle or habitat, a well-shielded area sometimes called a "storm shelter" or "safe haven" where the travelers could gather during the largest particle events. Intensity risetimes on the order of half an hour or more and overall event durations of 1 to 2 days would make actively seeking a well-shielded shelter for the duration a distinct possibility. The high-energy and penetrating nature and relative constancy of the galactic cosmic rays, on the other hand, do not allow the use of highly shielded areas as a means of protection against them. The first question to answer becomes: what is the risk to human health from the galactic cosmic rays? We need to have a good idea of the answer to this question before we can address the problem of how to best protect human health or, indeed, whether any specific measures need to be taken.

Cosmic Radiation↗