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PubMed2002

Measurements of cosmic-ray low-energy antiproton and proton spectra in a transient period of solar field reversal.

The energy spectra of cosmic-ray low-energy antiprotons ( *p's) and protons ( p's) have been measured by BESS in 1999 and 2000, during a period covering reversal at the solar magnetic field. Based on these measurements, a sudden increase of the *p/p flux ratio following the solar magnetic field reversal was observed, and it generally agrees with a drift model of the solar modulation.

Journal Article↗
PubMedDate not supplied

Non-light based ecosystems and bioastronomy.

The possibility of the existence of life beyond planet Earth has always fascinated humans. However, due to certain circumstances such as the failure of the Viking expeditions to detect any sign of biotic activity on Mars, and the understanding that the presence of life would lead to drastic alterations in the atmosphere of the host planet (alterations that have never been detected on other planets or planetoids of the solar system), the belief that our planet is the only planet to sustain life inside the solar system originated. During the last three decades a series of new complex biological communities have been discovered, in the deep sea, inside caves isolated from the external biosphere, and deep inside the crust of our planet, and found to depend on geothermal energy instead of solar energy for their survival. These discoveries give us new evidence and hope that life might exist not only on other planets, but perhaps even in other planetoids of our solar system. Life may exist in regions other than the surface of a planet, and these areas would be extremely difficult to identify.

Ecosystem↗
PubMed1999

Sun exposure and pterygium of the eye: a dose-response curve.

PURPOSE: To present a quantitative analysis of pterygium and ocular sun exposure, a dose-response curve, and a discussion of the health-promotion implications of the findings. METHODS: A hospital-based, case-control study was conducted in Perth, Western Australia. Case subjects had surgical removal of a pterygium; control subjects had an ear, nose, or throat procedure. A lifetime history of residence, sun exposure patterns, and use of hats, spectacles, and sunglasses was obtained at interview. Measures of potential sun exposure included latitude, daily sunshine hours, and daily global solar radiant energy. The most complex estimate of actual sun exposure was the daily ocular solar radiation dose, calculated from climatic data, time spent outdoors not under shade, and the use of hats and spectacles. RESULTS: There were strong positive associations between pterygium and measures of potential and actual sun exposure. Associations were as strong for whole-life measures as for those in any specific age range. Pterygium odds ratios increased with exposure level; the odds ratio was 4.0 (95% confidence interval, 1.6 to 10.9) for the highest quarter of the daily sun exposure. The strongest associations were seen for the estimated daily ocular solar radiation dose, with an odds ratio of 6.8 (95% confidence interval, 2.6 to 19.7) for the highest quarter of exposure. CONCLUSIONS: Pterygium is strongly related to ocular sun exposure, with little evidence that exposure during any particular period of life is more important than in other periods; the implication for prevention of pterygium is that ocular protection is beneficial at all ages.

Adult↗
PubMed2002

Measurement of day and night neutrino energy spectra at SNO and constraints on neutrino mixing parameters.

The Sudbury Neutrino Observatory (SNO) has measured day and night solar neutrino energy spectra and rates. For charged current events, assuming an undistorted 8B spectrum, the night minus day rate is 14.0%+/-6.3%(+1.5%)(-1.4%) of the average rate. If the total flux of active neutrinos is additionally constrained to have no asymmetry, the nu(e) asymmetry is found to be 7.0%+/-4.9%(+1.3%)(-1.2%). A global solar neutrino analysis in terms of matter-enhanced oscillations of two active flavors strongly favors the large mixing angle solution.

Journal Article↗
PubMed1982

The ocean as a supplier of food and energy.

This paper presents the concept of raising seaweeds and other valuable organisms with the aid of huge structures ('ocean farms') emplaced in the surface waters of the open oceans. Potential advantages from and difficulties to be expected in realizing the associated technologies are briefly set forth. Much of the published literature pertaining to the concept is referenced and summarized. Wave-powered upwelling of cool, nutrient-rich waters through vertical pipes extending to depths of 100-300 m is indicated as desirable. Technologies are outlined for using the harvested seaweeds to create foods and other valuable products such as animal feeds, fertilizers, fibers, plastics, synthetic natural gas (methane), and alcohol and gasoline fuels. Results from site selection studies and economic analyses are given. It appears that dynamically positioned farms orbiting with the surface current patterns typically found on the ocean will be most cost-effective. The general conclusion is stated that open ocean farming will become economically more feasible as the cheaper fossil fuels and food producing lands of the earth become increasingly consumed in the course of the next century.

Animals↗
PubMed1995

Primary production and humanosphere--is energy sufficient for sustainable humanosphere?

There is a growing concern about the sustainability of our humanosphere. Realizing that our consumption of natural resources is soon to exhaust available ones in this globe, we feel the need for more prudent ways to utilize them. In particular, the need would be greater in the ways for the use of the primary products as we are to continue to face the rapid increase in human population. On the contrary, however, we are rapidly losing the traditional customs of their many uses. For instance, rice straws were once a significant raw material for many manufactured products in Japan, while most of them are now simply burned in the paddy. Here I would like to review the current status of primary production on the Earth from the viewpoint of material cycling and to demonstrate that, unless we quickly turn around our ever-increasing demand for more material and more energy, the humanosphere would never enter a stable phase. At the year 2006 A.D., the energy demand of a possibly sustainable humanosphere surpasses the available energy through the global primary production.

Agriculture↗
PubMed1994

A model for the evolution of CO2 on Mars.

We have constructed a model that predicts the evolution of CO2 on Mars from the end of the heavy bombardment period to the present. The model draws on published estimates of the main processes believed to affect the fate of CO2 during this period: chemical weathering, regolith uptake, polar cap formation, and atmospheric escape. Except for escape, the rate at which these processes act is controlled by surface temperatures which we calculate using a modified version of the Gierasch and Toon energy balance model (1973, J. Atmos. Sci. 30, 1502-1508). The modifications account for the change in solar luminosity with time, the greenhouse effect, and a polar and solar equatorial energy budget. Using published estimates for the main parameters, we find no evolutionary scenario in which CO2 is capable of producing a warm (global mean temperatures>250 K) and wet (surface pressures>30 mbar) early climate, and then evolves to present conditions with approximately 7 mbar in the atmosphere, <300 mbar in the regolith, and <5 mbar in the caps. Such scenarios would only exist if the early sun were brighter than standard solar models suggest, if greenhouse gases other than CO2 were present in the early atmosphere, or if the polar albedo were significantly lower than 0.75. However, these scenarios generally require the storage of large amounts of CO2 (>1 bar) in the carbonate reservoir. If the warm and wet early Mars constraint is relaxed, then we find best overall agreement with present day reservoirs for initial CO2 inventories of 0.5-1.0 bar. We also find that the polar caps can a profound effect on how the system evolves. If the initial amount of CO2 is less than some critical value, then there is not enough heating of the poles to prevent permanent caps from forming. Once formed, these caps control how the system evolves, because they set the surface pressure and, hence, the thermal environment. If the initial amount of CO2 is greater than this critical value, then caps do not form initially, but can form later on, when weathering and escape lower the surface pressure to a point at which polar heating is no longer sufficient to prevent cap formation and the collapse of the climate system. Our modeling suggests this critical initial amount of CO2 is between 1 and 2 bar, but its true value will depend on all factors affecting the polar heat budget.

Atmosphere↗
PubMed2000

Extended magnetic reconnection at the Earth's magnetopause from detection of bi-directional jets

Magnetic reconnection is a process that converts magnetic energy into bi-directional plasma jets; it is believed to be the dominant process by which solar-wind energy enters the Earth's magnetosphere. This energy is subsequently dissipated by magnetic storms and aurorae. Previous single-spacecraft observations revealed only single jets at the magnetopause--while the existence of a counter-streaming jet was implicitly assumed, no experimental confirmation was available. Here we report in situ two-spacecraft observations of bi-directional jets at the magnetopause, finding evidence for a stable and extended reconnection line; the latter implies substantial entry of the solar wind into the magnetosphere. We conclude that reconnection is determined by large-scale interactions between the solar wind and the magnetosphere, rather than by local conditions at the magnetopause.

Journal Article↗
PubMed2004

Density-functional study of organic-inorganic hybrid single crystal ZnSe(C2H8N2)(1/2).

Unusual properties (i.e., strong band dispersion, high carrier mobility, wide absorption-energy window, and sharp band-edge transition) that are desirable for hybrid-material electronics and for solar electric energy conversion are predicted to exist in the organic-inorganic chalcogenide single crystal ZnSe(C2H8N2)(1/2) by using density-functional calculations. A simple mechanism, namely that the band-edge electronic states of the hybrid composite is predominantly determined by the inorganic constituent, is revealed to be responsible for governing these properties. Suggestions for further engineering hybrid semiconductors are also provided

Journal Article↗