The interpretation of data from the Viking Mars Atmospheric Water Detectors (MAWD): Some points for discussion

Properly interpreted, water vapor column abundance measurements can provide important insights into many of the processes that govern the diurnal, seasonal, and climatic cycles of atmospheric water on Mars. The uncertain distribution of water vapor complicates this analysis. It is argued that if a significant fraction of the total atmospheric vapor content is concentrated within the lowermost scale height, then the hemispheric asymmetry in zonally averaged topography/air mass might itself explain the observed gradient in the annual and zonally averaged vapor abundance

Mars: Crustal pore volume, cryospheric depth, and the global occurrence of groundwater

It is argued that most of the Martian hydrosphere resides in a porous outer layer of crust that, based on a lunar analogy, appears to extend to a depth of about 10 km. The total pore volume of this layer is sufficient to store the equivalent of a global ocean of water some 500 to 1500 m deep. Thermal modeling suggests that about 300 to 500 m of water could be stored as ice within the crust. Any excess must exist as groundwater

MECA Workshop on Atmospheric H2O Observations of Earth and Mars. Physical Processes, Measurements and Interpretations

The workshop was held to discuss a variety of questions related to the detection and cycling of atmospheric water. Among the questions addressed were: what factors govern the storage and exchange of water between planetary surfaces and atmospheres; what instruments are best suited for the measurement and mapping of atmospheric water; do regolith sources and sinks of water have uniquely identifiable column abundance signatures; what degree of time and spatial resolution in column abundance data is necessary to determine dynamic behavior. Of special importance is the question, does the understanding of how atmospheric water is cycled on Earth provide any insights for the interpretation of Mars atmospheric data

Scientific Results of the Nasa-sponsored Study Project on Mars: Evolution of Its Climate and Atmosphere

The scientific highlights of the Mars: Evolution of its Climate and Atmosphere (MECA) study project are reviewed and some of the important issues in Martian climate research that remain unresolved are discussed

Martian geomorphology and its relation to subsurface volatiles

Martian volatile inventory, planetary climatic and atmospheric evolution, and the interpretation of various remote sensing data were discussed. A number of morphologies that were cited as potential indicators of subsurface volatiles were reviewed. Rampart craters and terrain softening were the focus of more in-depth discussion because of the popular attention they have received and the fact that their areal distributions are by far the most extensive of all the proposed indicators

Piezoelectric-based apparatus for strain tuning

We report the design and construction of piezoelectric-based apparatus for applying continuously tuneable compressive and tensile strains to test samples. It can be used across a wide temperature range, including cryogenic temperatures. The achievable strain is large, so far up to 0.23% at cryogenic temperatures. The apparatus is compact and compatible with a wide variety of experimental probes. In addition, we present a method for mounting high-aspect-ratio samples in order to achieve high strain homogeneity.Comment: 8 pages, 8 figure

Vibrational-Resonance Enhancement of Positron Annihilation in Molecules

A first study of positron annihilation as a function of positron energy was performed. The rate of annihilation of low-energy positrons in molecular gases was discussed. It was shown that the large observed values of annihilation rates are due to the excitation of long-lived vibrational resonances of the positron-molecule complex. The results are consistent with a theoretical model of resonant annihilation

Mars, evolution of its climate and atmosphere

The scientific highlights of the Mars: Evolution of its Climate and Atmosphere (MECA) study project are reviewed and some of the important issues in Martian climate research that remain unresolved are discussed.Stephen M. Clifford, Ronald Greeley, Robert M. Haberle ; compiled by the Lunar and Planetary Institute.Project Summary -- Science Report -- Origin of MECA -- MECA Membership List -- MECA Bibliograph

Dietary nitrate and population health: a narrative review of the translational potential of existing laboratory studies

BACKGROUND: Dietary inorganic nitrate (NO(3)(−)) is a polyatomic ion, which is present in large quantities in green leafy vegetables and beetroot, and has attracted considerable attention in recent years as a potential health-promoting dietary compound. Numerous small, well-controlled laboratory studies have reported beneficial health effects of inorganic NO(3)(−) consumption on blood pressure, endothelial function, cerebrovascular blood flow, cognitive function, and exercise performance. Translating the findings from small laboratory studies into ‘real-world’ applications requires careful consideration. MAIN BODY: This article provides a brief overview of the existing empirical evidence basis for the purported health-promoting effects of dietary NO(3)(−) consumption. Key areas for future research are then proposed to evaluate whether promising findings observed in small animal and human laboratory studies can effectively translate into clinically relevant improvements in population health. These proposals include: 1) conducting large-scale, longer duration trials with hard clinical endpoints (e.g. cardiovascular disease incidence); 2) exploring the feasibility and acceptability of different strategies to facilitate a prolonged increase in dietary NO(3)(−) intake; 3) exploitation of existing cohort studies to explore associations between NO(3)(−) intake and health outcomes, a research approach allowing larger samples sizes and longer duration follow up than is feasible in randomised controlled trials; 4) identifying factors which might account for individual differences in the response to inorganic NO(3)(−) (e.g. sex, genetics, habitual diet) and could assist with targeted/personalised nutritional interventions; 5) exploring the influence of oral health and medication on the therapeutic potential of NO(3)(−) supplementation; and 6) examining potential risk of adverse events with long term high- NO(3)(−) diets. CONCLUSION: The salutary effects of dietary NO(3)(−) are well established in small, well-controlled laboratory studies. Much less is known about the feasibility and efficacy of long-term dietary NO(3)(−) enrichment for promoting health, and the factors which might explain the variable responsiveness to dietary NO(3)(−) supplementation between individuals. Future research focussing on the translation of laboratory data will provide valuable insight into the potential applications of dietary NO(3)(−) supplementation to improve population health

Water in a Changing World

Life on earth depends on the continuous flow of materials through the air, water, soil, and food webs of the biosphere. The movement of water through the hydrological cycle comprises the largest of these flows, delivering an estimated I 10,000 cubic kilometers (km^\u3e of water to the land each year as snow and rainfall. Solar energy drives the hydrological cycle, vaporizing water from the surface of oceans, lakes, and rivers as well as from soils and plants (evapotranspiration). Water vapor rises into the atmosphere where it cools, condenses, and eventually rains down anew. This renewable freshwater supply sustains life on the land, in estuaries, and in the freshwater ecosystems of the earth