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PubMedDate not supplied

Using the science fiction film invaders from Mars in a child psychiatry seminar.

OBJECTIVE: The science fiction film Invaders From Mars is used to teach principles of child development; clinical features of separation anxiety and nightmares; and clinical interventions, including child psychotherapy, child protective issues, and crisis management. METHODS: Commercial films have been used as teaching aids in child psychiatry seminars. In this child psychiatry seminar, Invaders From Mars is viewed, and relevant teaching points are discussed with child psychiatry residents. RESULTS: The response of child psychiatry residents has been positive, with high ratings. CONCLUSION: This film may serve as a useful tool for teaching child psychiatry residents principles of child development, clinical features of separation anxiety and nightmares, and basic clinical interventions.

Capgras Syndrome↗
PubMed2001

Space radiation cancer risks and uncertainties for Mars missions.

Projecting cancer risks from exposure to space radiation is highly uncertain because of the absence of data for humans and because of the limited radiobiology data available for estimating late effects from the high-energy and charge (HZE) ions present in the galactic cosmic rays (GCR). Cancer risk projections involve many biological and physical factors, each of which has a differential range of uncertainty due to the lack of data and knowledge. We discuss an uncertainty assessment within the linear-additivity model using the approach of Monte Carlo sampling from subjective error distributions that represent the lack of knowledge in each factor to quantify the overall uncertainty in risk projections. Calculations are performed using the space radiation environment and transport codes for several Mars mission scenarios. This approach leads to estimates of the uncertainties in cancer risk projections of 400-600% for a Mars mission. The uncertainties in the quality factors are dominant. Using safety standards developed for low-Earth orbit, long-term space missions (>90 days) outside the Earth's magnetic field are currently unacceptable if the confidence levels in risk projections are considered. Because GCR exposures involve multiple particle or delta-ray tracks per cellular array, our results suggest that the shape of the dose response at low dose rates may be an additional uncertainty for estimating space radiation risks.

Cosmic Radiation↗
PubMed2003

Radiation-dependent limit for the viability of bacterial spores in halite fluid inclusions and on Mars.

When claims for the long-term survival of viable organisms are made, either within terrestrial minerals or on Mars, considerations should be made of the limitations imposed by the naturally occurring radiation dose to which they have been exposed. We investigated the effect of ionizing radiation on different bacterial spores by measuring the inactivation constants for B. subtilis and S. marismortui spores in solution as well as for dry spores of B. subtilis and B. thuringiensis. S. marismortui is a halophilic spore that is genetically similar to the recently discovered 2-9-3 bacterium from a halite fluid inclusion, claimed to be 250 million years old (Vreeland et al., Nature 407, 897-900, 2000). B. thuringiensis is a soil bacterium that is genetically similar to the human pathogens B. anthracis and B. cereus (Helgason et al., Appl. Environ. Microbiol. 66, 2627-2630, 2000). To relate the inactivation constant to some realistic environments, we calculated the radiation regimen in a halite fluid inclusion and in the Martian subsurface over time. Our conclusion is that the ionizing dose of radiation in those environments limits the survival of viable bacterial spores over long periods. In the absence of an active repair mechanism in the dormant state, the long-term survival of spores is limited to less than 109 million years in halite fluid inclusions, to 100 to 160 million years in the Martian subsurface below 3 m, and to less than 600,000 years in the uppermost meter of Mars.

Mars↗
PubMed1998

Search for life on Mars.

A multi-user integrated suite of instruments designed to optimize the search for evidence of life on Mars is described. The package includes: -Surface inspection and surface environment analysis to identify the potential Mars landing sites, to inspect the surface geology and mineralogy, to search for visible surficial microbial macrofossils, to study the surface radiation budget and surface oxidation processes, to search for niches for extant life. -Subsurface sample acquisition by core drilling -Analysis of surface and subsurface minerals and organics to characterize the surface mineralogy, to analyse the surface and subsurface oxidants, to analyse the mineralogy of subsurface aliquots, to analyse the organics present in the subsurface aliquots (elemental and molecular composition, isotopes, chirality). -Macroscopic and microscopic inspection of subsurface aliquots to search for life's indicators (paleontological, biological, mineralogical) and to characterize the mineralogy of the subsurface aliquots. The study is led by ESA Manned Spaceflight and Microgravity Directorate.

Europe↗
PubMed1990

Essay: should we implant life on Mars?

The question of whether or not we should implant life on Mars has at its core another question. Could we implant life on Mars? As interesting as the ethical considerations of the proposition are--and we shall look at these--they are moot unless the concept itself is feasible.

Ecosystem↗
PubMed1991

Human exploration of Mars.

The human exploration of Mars has the potential to return a rich harvest of scientific information about that planet, its possible past biological history and the prospects for future habitation by Earthly life. The realization of that potential will require new approaches and new technologies--a whole new paradigm in space exploration. Picture yourself exploring the surface of Mars, where your task involves conducting a detailed investigation of features larger than the United States in order to uncover a record of planetary history spanning over four billion years.

Atmosphere↗
PubMed1995

The circum-Chryse region as a possible example of a hydrologic cycle on Mars: geologic observations and theoretical evaluation.

The transection and superposition relationships among channels, chaos, surface materials units, and other features in the circum-Chryse region of Mars were used to evaluate relative age relationships and evolution of flood events. Channels and chaos in contact (with one another) were treated as single discrete flood-carved systems. Some outflow channel systems form networks and are inferred to have been created by multiple flood events. Within some outflow channel networks, several separate individual channel systems can be traced to a specific chaos which acted as flood-source area to that specific flood channel. Individual flood-carved systems were related to widespread materials units or other surface features that served as stratigraphic horizons. Chryse outflow channels are inferred to have formed over most of the perceivable history of Mars. Outflow channels are inferred to become younger with increasing proximity to the Chryse basin. In addition, outflow channels closer to the basin show a greater diversity in age. The relationship of subsequent outflow channel sources to the sources of earlier floods is inferred to disfavor episodic flooding due to the progressive tapping of a juvenile near-surface water supply. Instead, we propose the circum-Chryse region as a candidate site of past hydrological recycling. The discharge rates necessary to carve the circum-Chryse outflow channels would have inevitably formed temporary standing bodies of H2O on the Martian surface where the flood-waters stagnated and pooled (the Chryse basin is topographically enclosed). These observations and inferences have led us to formulate and evaluate two hypotheses: (1) large amounts of the sublimated H2O off the Chryse basin flood lakes precipitated (snowed) onto the flood-source highlands and this H2O was incorporated into the near surface, recharging the H2O sources, making possible subsequent deluges; and (2) ponded flood-water in Chryse basin drained back down an anti basinward dipping subsurface layer accessed long the southern edge of the lake, recharging the flood-source aquifers. H2O not redeposited in the flood-source region was largely lost to the hydrologic cycle. This loss progressively lowered the vitality of the cycle, probably by now killing it. Our numerical evaluations indicate that of the two hypotheses we formulated, the groundwater seep cycle seems by far the more viable. Optimally, approximately 3/4 of the original mass of an ice-covered cylindrical lake (albedo 0.5, 1 km deep, 100-km radius, draining along its rim for one quarter of its circumference into substrata with a permeability of 3000 darcies) can be modeled to have moved underground (on timescales of the order of 10(3) years) before the competing mechanisms of sublimation and freeze down choked off further water removal. Once underground, this water can travel distances equal to the separation between Chryse basin and flood-source sites in geologically short (approximately 10(6) year-scale) times. Conversely, we calculate that optimally only approximately 40% of the H2O carried from Chryse can condense at the highlands, and most of the precipitate would either collect at the base of the highlands/lowlands scarp or sublimate at rates greater than it would accumulate over the flood-source sites. Further observations from forthcoming missions may permit the determination of which mechanisms may have operated to recycle the Chryse flood-waters.

Disasters↗
PubMed1993

Gaia and the colonization of Mars.

The Gaia hypothesis states that the atmosphere, hydrosphere, surface sediments, and life on Earth behave dynamically as a single integrated physiological system. What has been traditionally viewed as the passive environment is a highly active, integral part of the gaian system. Aspects of the surface temperature and chemistry are regulated by the sum of life, the biota. Formulated first by James E. Lovelock, in the late 1960s, the Gaia hypothesis has been in the scientific literature for more than 25 years. Because of its properties of exponential growth and propagation, life is a powerful geologic force. A useful aspect of the Gaia idea is that it requires integration of scientific disciplines for the study of Earth. The recently touted Earth system science is broadly parallel with the gaian concept of the physiochemical regulation of Earth's surface. We discuss here, in a gaian context, the colonization of Mars by Earth organisms. Although colonizing Mars may be impossible, its accomplishment would be exactly equivalent to "the reproduction of Gaia by budding."

Atmosphere↗
PubMed1995

Genetic modification and selection of microorganisms for growth on Mars.

Genetic engineering has often been suggested as a mechanism for improving the survival prospects of terrestrial microoganisms when seeded on Mars. The survival characteristics that these pioneer microorganisms could be endowed with and a variety of mechanisms by which this can be achieved are discussed, together with an overview of some of the potential hurdles that must be overcome. Also, a number of biologically useful properties for these microorganisms are presented that could facilitate the initial human colonisation and ultimately the planetary engineering of Mars.

Bacteria, Anaerobic↗
PubMed1964

The atmospheres of Mars, Venus and Jupiter.

The general properties of the atmospheres of Mars, Venus and Jupiter are reviewed. The evolutionary processes of planetary atmospheres are outlined as an introduction to a detailed discussion of the structure of the atmospheres of other planets. The most recent observational results indicate that the surface pressure on Mars could be as low as 20 mb, and the amount of CO2 may have a mixing ratio as high as 25% by volume. For Venus, the Mariner II results suggest that the surface temperature may actually be of the order of 600 degrees K. Also there are indications that the surface pressure on Venus could be approximately 100 atm., with the atmosphere mainly composed of N2. In the case of Jupiter, recent theoretical investigations of the atmosphere below the clouds suggest, that there may be regions in the atmosphere of very high density and pressure but at relatively low temperature, creating conditions possibly favorable to the occurrence of complex organic reactions.

Atmosphere↗
PubMed2003

[Cryptobiosphere of Mars].

The US Viking missions (1975-1976) failed to discover any biological activity on the surface of Mars. Yet, life may exist in the planet lithosphere which was found to contain a substantial amount of water. Martian interior can also provide microbial cryptolife with sources of carbon (CO, CO2, CH4) and energy (reduced elements and compounds, e.g. H2, CO, H2S, NH4+, CH4, Fe3+). Microorganisms identical to the Earth's anaerobic methanogens, sulfate reducers, acetogens, denitrifiers etc. are the most probable Martian aborigines. Well-balanced continuous functioning of the Martian cryptobiosphere implies closure of biochemical carbon, sulfur and nitrogen cycles which cannot be reached but with participation of organotrophic and anaerobic hydrolytic and zymotic organisms, ammonifiers and denitrifiers. Considering the low intensity of biological and chemical processes in the absence of surface hydrosphere, low-power atmosphere and cryptobiosphere closure on Mars, and slow global energy matter cycles, evolution of the presumable Martian cryptolife should also go at a slack pace and directions and forms of the evolution of living substance can have little in common with those on Earth. Comprehensive investigations of the Martian biota will employ a great variety of geochemical, radi- and stable isotope, microbiological, enzymatic and molecular biology methods.

Aerobiosis↗
PubMed2003

[Consideration of the deuterium-free water supply to an expedition to Mars].

Interplanetary missions, including to Mars, will put crews into severe radiation conditions. Search for methods of reducing the risk of radiation-induced cancer is of the top priority in preparation for the mission to Mars. One of the options is designing life support systems that will generate water with low content of the stable hydrogen isotope (deuterium) to be consumed by crewmembers. Preliminary investigations have shown that a decrease of the deuterium fraction by 65% does impart to water certain anti-cancer properties. Therefore, drinking deuterium-free water has the potential to reduce the risk of cancer consequent to the extreme radiation exposure of the Martian crew.

Animals↗
PubMed2004

[Radiation risk to cosmonauts in a flight to Mars].

The paper presents results of the 14-year studies (1966-1980) with dogs irradiated by presumable doses of the galactic cosmic rays (GCR) and solar cosmic rays (SCR) that might affect cosmonauts during a flight to Mars. Along with data of chronic experiments with small laboratory animals exposed to a broad variety of dose rates, our data formed a basis for construction of mathematical models of processes of radiation damage to living organisms, and growth of the probability of mammal death or life span reduction caused by repeated acute and chronic irradiation by different dose rates. Described are present-date estimates of equivalent doses from GCR and SCR behind various shields, and radiation risks for cosmonauts of different age on a mission to Mars. Also compared are values of total radiation risks over the length of life, risks of cancer and lifetime reduction after the planetary mission derived by the mathematical modeling and calculation.

Age Factors↗
PubMedDate not supplied

Water related environment modelling on Mars.

During a human Mars exploration because of the lack of time astronauts need fast methods for the interpretation of unexpected observations which give them flexibility and new, important targets. With in-situ modelling it is possible to get information on various past and present processes at the same location on a far wider spectrum than would be realized even during a long mission. This work summarizes the potential technical requirements and benefits of the modelling. Based on a simple estimation with a 300 kg package, and 1-10% of the working time of 1-2 astronauts at the same location, they can get plenty of new and important information for the whole past and present Mars. With the proposed five test groups astronauts will be able to make better and newer kinds of interpretations of observations, and find better targets and methods during the same mission.

Astronauts↗
PubMed1996

Water on early Mars.

Large flood channels, valley networks and a variety of features attributed to the action of ground ice indicate that Mars emerged from heavy bombardment 3.8 Ga ago, with an inventory of water at the surface equivalent to at least a few hundred metres spread over the whole planet, as compared with 3 km for the Earth. The mantle of Mars is much drier than that of the Earth, possibly as a result of global melting at the end of accretion and the lack of plate tectonics to subsequently reintroduce water into the interior. The surface water resided primarily in a porous, kilometres-thick megaregolith created by the high impact rates. Under today's climatic conditions groundwater is trapped below a thick permafrost zone. At the end of heavy bombardment any permafrost zone would have been much thinner because of the high heat flows, but climatic conditions may have been very different then, as suggested by erosion rates 1000 times higher than subsequent rates. Water trapped below the permafrost periodically erupted onto the surface to form large flood channels and lakes. Given abundant water at the surface and sustained volcanism, hydrothermal activity must have frequently occurred but we have yet to make the appropriate observations to detect the results of such activity.

Climate↗
PubMed1997

Mars Pathfinder [foldout].

The following foldout present images and analysis from the Mars Pathfinder Mission that are discussed in seven subsequent Reports. The center is a four-page panorama of the surface of Mars around the lander (Plate 1). The back of the foldout contains surface images (Plate 7), a different perspective of the landing site (Plate 2), rover targets (Plate 3), locations of rocks and other features (Plate 6) and data analysis (Plates 4, 4, 8, 9, and 10).

Extraterrestrial Environment↗
PubMed1996

Binding of MAR-DNA elements by mutant p53: possible implications for its oncogenic functions.

The tumor suppressor p53 is a multifunctional protein whose main duty is to preserve the integrity of the genome. This function of wild-type p53 as "guardian of the genome" is achieved at different levels, as a cell cycle checkpoint protein, halting the cell cycle upon DNA damage, and via a direct involvement in processes of DNA repair. Alternatively, p53 can induce apoptosis. Mutations in the p53 gene occur in about 50% of all human tumors and eliminate the tumor suppressor functions of p53. However, many mutant p53 proteins have not simply lost tumor suppressor functions but have gained oncogenic properties which contribute to the progression of tumor cells to a more malignant phenotype. The molecular basis for this gain of function of mutant p53 is still unknown. However, mutant (mut) p53 specifically binds to nuclear matrix attachment region (MAR) DNA elements. MAR elements constitute important higher order regulatory elements of chromatin structure and function. By binding to these elements, mut p53 could modulate important cellular processes, like gene expression, replication, and recombination, resulting in phenotypic alterations of the tumor cells. Mut p53 thus could be the first representative of a new class of oncogenes, which exert their functions via long-range alterations or perturbation of chromatin structure and function.

Animals↗
PubMed1982

The measurement of mathematics anxiety: the Mathematics Anxiety Rating Scale for Adolescents--MARS-A.

Describes the Mathematics Anxiety Rating Scale for Adolescents (MARS-A). Normative data on over 1,200 junior high and senior high students are reported. In addition, psychometric data that relate to reliability and construct validity for the MARS-A scale are discussed. Two factors were identified in the scale, a factor of numerical anxiety that appeared in 91% of the items and a factor of mathematics test anxiety that appeared in the remaining items. Results that show the association between high mathematics anxiety scale scores and low grade average in mathematics courses are reported on two samples of students.

Adolescent↗