Early martian environments: the Antarctic and other terrestrial analogs.

The comparability of the early environments of Mars and Earth, and the biological evolution which occurred on early earth, motivates serious consideration of the possibility of an early martian biota. Environments which could have contained this early martian life and which may presently contain evidence of this former life include aquatic, ice, soil, and rock habitats. Several analogs of these potential early martian environments, which can provide useful information in searching for extinct life on Mars, are currently available for study on Earth. These terrestrial analogs include the perennially ice-covered lakes and sandstone rocks in the Polar Deserts of Antarctica, surface of snowfields and glaciers, desert soils, geothermal springs, and deep subsurface environments.     

An evaluation of the IRI-2007 storm time model at low latitude stations

This paper discusses the ability of the International Reference Ionosphere IRI-2007 storm time model to predict foF2 ionospheric parameter during geomagnetic storm periods. Experimental data (based on availability) from two low latitude stations: Vanimo (geographic coordinates, 2.7 °S, 141.3 °E, magnetic coordinates, 12.3 °S, 212.50 °E) and Darwin (geographic coordinates, 12.45 °S, 130.95 °E, magnetic coordinates, 22.9 °S, 202.7 °E) during nine storms that occurred in 2000 (Rz₁₂ = 119), 2001(Rz₁₂ = 111) and 2003 (Rz₁₂ = 64) are compared with those obtained by the IRI-2007 storm model. The results obtained show that the percentage deviation between the experimental and IRI predicted foF2 values during these storm periods is as high as 100% during the main and recovery phases. Based on the values of “relative deviation module mean” (RDMM) obtained (i.e. between 0.08 and 0.60), it is observed that there is a reasonable to poor agreement between measured foF2 values and the IRI-storm model prediction values during main and recovery phases of the storms under investigation. As a result, in addition to other studies that have been carried out from different sectors, more studies are required to be carried out. This will enable IRI community to improve on the present performance of the model. In general the IRI-storm model predictions follow normal trend of the foF2 measured values but does not reproduce well the measured values.     

Mapping mean lake surface from satellite altimetry and GPS kinematic surveys

Lake water height is a key variable in water cycle and climate change studies, which is achievable using satellite altimetry constellation. A method based on data processing of altimetry from several satellites has been developed to interpolate mean lake surface (MLS) over a set of 22 big lakes distributed on the Earth. It has been applied on nadir radar altimeters in Low Resolution Mode (LRM: Jason-3, Saral/AltiKa, CryoSat-2) in Synthetic Aperture Radar (SAR) mode (Sentinel-3A), and in SAR interferometric (SARin) mode (CryoSat-2), and on laser altimetry (ICESat). Validation of the method has been performed using a set of kinematic GPS height profiles from 18 field campaigns over the lake Issykkul, by comparison of altimetry’s height at crossover points for the other lakes and using the laser altimetry on ICESat-2 mission. The precision reached ranges from 3 to 7 cm RMS (Root Mean Square) depending on the lakes. Currently, lake water level inferred from satellite altimetry is provided with respect to an ellipsoid. Ellipsoidal heights are converted into orthométric heights using geoid models interpolated along the satellite tracks. These global geoid models were inferred from geodetic satellite missions coupled with absolute and regional anomaly gravity data sets spread over the Earth. However, the spatial resolution of the current geoid models does not allow capturing short wavelength undulations that may reach decimeters in mountaineering regions or for rift lakes (Baikal, Issykkul, Malawi, Tanganika). We interpolate in this work the geoid height anomalies with three recent geoid models, the EGM2008, XGM2016 and EIGEN-6C4d, and compare them with the Mean Surface of 22 lakes calculated using satellite altimetry. Assuming that MLS mimics the local undulations of the geoid, our study shows that over a large set of lakes (in East Africa, Andean mountain and Central Asia), short wavelength undulations of the geoid in poorly sampled areas can be derived using satellite altimetry. The models used in this study present very similar geographical patterns when compared to MLS. The precision of the models largely depends on the location of the lakes and is about 18 cm, in average over the Earth. MLS can serve as a validation dataset for any future geoid model. It will also be useful for validation of the future mission SWOT (Surface Water and Ocean Topography) which will measure and map water heights over the lakes with a high horizontal resolution of 250 by 250 m.     

Testing a Mars science outpost in the Antarctic dry valleys.

Field research conducted in the Antarctic has been providing insights about the nature of Mars in the science disciplines of exobiology and geology. Located in the McMurdo Dry Valleys of southern Victoria Land (160 degrees and 164 degrees E longitude and 76 degrees 30' and 78 degrees 30' S latitude), research outposts are inhabited by teams of 4-6 scientists. We propose that the design of these outposts be expanded to enable meaningful tests of many of the systems that will be needed for the successful conduct of exploration activities on Mars. Although there are some important differences between the environment in the Antarctic dry valleys and on Mars, the many similarities and particularly the field science activities, make the dry valleys a useful terrestrial analog to conditions on Mars. Three areas have been identified for testing at a small science outpost in the dry valleys; 1) studying human factors and physiology in an isolated environment; 2) testing emerging technologies (e.g., innovative power management systems, advanced life support facilities including partial bioregenerative life support systems for water recycling and food growth, telerobotics, etc.); and 3) conducting basic scientific research that will enhance our understanding of Mars while contributing to the planning for human exploration. We suggest that an important early result of a Mars habitat program will be the experience gained by interfacing humans and their supporting technology in a remote and stressful environment.     

Morphometric,rheological and compositional analysis of an effusive lunar dome using high resolution remote sensing data sets: A case study from Marius hills region

Domes, an analog of the terrestrial shield volcanoes are one of the important volcanic features found on the lunar surface. Such volcanic features are windows to better understanding of the contrasting natures of lunar volcanism, giving an insight into the source and the nature of the basaltic magmas. Marius Hills Complex is one of the most important regions in the entire lunar surface for having a complex setting of volcanic constructs with an abundant number of volcanic features like domes, cones and rilles. As a part of initiation of the study of Marius Hills volcanism, an effusive dome located to the south of Rima Galilaei, near the contact of Imbrian and Eratosthenian geological units is taken for the present study. Inferring from the Terrain Mapping Camera-Digital Elevation Model (TMC-DEM), the morphometric parameters are estimated (350 m in height, 9.62 km in diameter), and accordingly the rheological parameters are also estimated. As the signatures of multiphase eruption are not clear geomorphologically and also in topography, the dome is assumed to evolved in monogenetic eruption. The causative dike parameters of the dome are estimated, which gives upper bounds of true values of the parameters. The estimated feeder dike length (150 km) and width (233 m) implies that the source region is lying most probably in the mantle portion of moon. The crater size frequency distribution (CSFD) is applied to determine the age of the particular dome and also the surrounding mare surface so as to better construct a stratigraphic correlation. It is found that dome belongs to oldest age unit of Marius Hills region while the surrounding units are relatively younger. Using Chandrayaan-I Moon Mineralogy Mapper (M³) data, the surface composition for the study area is also analysed. Thus, the morphometry, rheology, dike parameters, age determination and mineralogy are found to be in good agreement with results of the earlier studies. Such a study, covering all the domes and other volcanic features in Marius Hills using high resolution data sets will provide a clear and better understanding of the volcanic history of the region and the Oceanus Procellarum Basin as well. In such a study, the application potential of high resolution Chandrayaan-I TMC image and its DEM generated from the stereo data has been useful.     

Transformation of a delta: Converting estuaries to lakes

In this century large-scale transformations have been carried out in the delta of the Rhine, Meuse and Scheldt in The Netherlands. The following principal consequences are considered: the loss of estuarine ecosystems, the change in the process of sedimentation and erosion, and the development of new aquatic and terrestrial ecosystems. The ecological consequences of the transformation of the Grevelingen estuary into a salt-water lake and some surprising developments are described briefly. The need for a limited restoration of the water exchange between the lake and the North Sea is indicated, as well as the major impacts of the exchange. The necessity for the maintenance or restoration of estuaries, the ecological development and the possibilities of the new lakes, and the management of these lakes by engineering structures are discussed. Careful land-use planning and ecosystem management, backed by research, are needed to make the fullest possible use of the potential offered by new lakes. It is also concluded that salt lakes have interesting perspectives.     

2010年海口上空突发钠层事件观测

使用钠荧光激光雷达观测2010年低纬度地区海口(20.0°N, 110.3°E)上空突发钠层事件. 2010年总计观测时间为458h, 观测到突发钠层事件38次, 即每观测12h有1次突发钠层事件发生. 结合武汉上空突发钠层数据, 对比巴西低纬度地区数据, 揭示低纬度地区突发钠层频发现象. 观测到2010年12月30日突发钠层峰值时刻钠层密度廓线具有很好的空间对称性. 分析了距海口激光雷达西南约160km中国海南澹州(19.5°N, 109.1°E)的测高仪数据, 检测了13对突发钠层和电离层偶发事件, 结果表明突发钠层与Es有很强的相关性. 通过 分析低纬度地区上空突发钠层峰值径迹平均速度发现, 大多数突发钠层峰值向 下运动.     

Comparison of GPS derived TEC with the TEC predicted by IRI 2012 model in the southern Equatorial Ionization Anomaly crest within the Eastern Africa region

We have compared the TEC obtained from the IRI-2012 model with the GPS derived TEC data recorded within southern crest of the EIA in the Eastern Africa region using the monthly means of the 5 international quiet days for equinoxes and solstices months for the period of 2012 – 2013. GPS-derived TEC data have been obtained from the Africa array and IGS network of ground based dual-frequency GPS receivers from four stations (Kigali (1.95°S, 30.09°E; Geom. Lat. 11.63°S), Malindi (2.99°S, 40.19°E; Geom. Lat. 12.42°S), Mbarara (0.60°S, 30.74°E; Geom. Lat. 10.22°S) and Nairobi (1.22°S, 36.89°E; Geom. Lat. 10.69°S)) located within the EIA crest in this region. All the three options for topside Ne of IRI-2012 model and ABT-2009 for bottomside thickness have been used to compute the IRI TEC. Also URSI coefficients were considered in this study. These results are compared with the TEC estimated from GPS measurements. Correlation Coefficients between the two sets of data, the Root-Mean Square Errors (RMSE) of the IRI-TEC from the GPS-TEC, and the percentage RMSE of the IRI-TEC from the GPS-TEC have been computed. Our general results show that IRI-2012 model with all three options overestimates the GPS-TEC for all seasons and at all stations, and IRI-2001 overestimates GPS-TEC more compared with other options. IRI-Neq and IRI-01-corr are closely matching in most of the time. The observation also shows that, GPS TEC are underestimated by TEC from IRI model during noon hours, especially during equinoctial months. Further, GPS-TEC values and IRI-TEC values using all the three topside Ne options show very good correlation (above 0.8). On the other hand, the TEC using IRI-Neq and IRI-01- corr had smaller deviations from the GPS-TEC compared to the IRI-2001.     

A REPORT OF GROUND EXPERIMENTS FOR BRAIN FUNCTION IN SPACE

The brain function is of crucial importance in space adaptation and astronaut performance. According to the theory of nonequiliblium fluctuations a new technology, ET (Elec-troencephalofluctuography [EEFG] Technology), has been developed in our laboratory for space application. Information of different attracters, especially the dominant supra-slow (S) oscillations of the brain can be abstracted from the fluctuating brain waves. Specific Sspectral lines related to neurophysiological and neuro-chemical activities have been identified and charcteristic spatial patterns have been figured out. ETanalysis has been carried out in a series of ground experiments: (1) 20 degrees head lowered suspension experiments in rabbits; (2) 2Gz hypergravity experiments in rabbits; (3) effects of antimotionsickness drugs on rabbits during suspension; (4) clincal observations on patients with brain circulation diseases. Valuable information has been collected in all these experiments, which can hardly be obtained by means of other existing techniques. The potentiality of ETapplication in space research was discussed.      

The effects of simulated microgravity on the seminiferous tubules of rats

Space flight has been shown to have many adverse effects on various systems throughout the body. Because the opportunity to place research animals on board a Space Shuttle or the International Space Station is infrequent, various techniques have been designed to simulate the effects of microgravity in Earth based laboratories. A commonly used technique is known as antiorthostatic suspension, also often referred to as hind limb suspension. In this technique the hind portion of the animal is raised so that its hind limbs are non-weight bearing. This places the animal in roughly a 30° head down tilt position. This results in cephalic fluid shifts similar to those seen in actual space flight. This technique has also been shown to mimic other physiological parameters that are affected during space flight. This study examined testicular tissue from rats subjected to a 7 day antiorthostatic suspension. This tissue was acquired through a tissue sharing program and some of the experimental animals were injected with Interleukin 1 receptor antagonist (IL-1ra) which was hoped to ameliorate some of the effects of antiorthostatic suspension. The injection of IL-1ra was not expected to have any effect on testicular tissue, however this tissue was included in the morphological and statistical analysis to conduct a more complete study. All tissues were embedded in paraffin, sectioned, and stained using standard H&E staining. The tissue was then qualitatively ranked according to the “health” of the seminiferous tubules. Our findings indicate that 7 days of antiorthostatic suspension had adverse effects on the tissue that comprises the walls of the seminiferous tubules. It has long been known that antiorthostatic suspension has deleterious effects on testicular tissue, however this research indicates that these effects occur much faster than indicated by previous researchers. This is a significant finding because it indicates that meaningful earth based studies in this area can be carried out in a shorter time span. This could result in more studies per year as well as saving money by avoiding longer than necessary animal suspensions. This is especially important as we enter an era when, without Space Shuttle, flight opportunities will become scarce. These antiorthostatic suspension studies indicate that space flight, even short duration spaceflight, may have harmful effects on the seminiferous tubules and blood-testis barrier of astronauts.     

Azimuthal propagation of Pc5 geomagnetic field pulsations in the southern polar cap

A statistical analysis of low frequency geomagnetic fluctuations at the two Antarctic stations Mario Zucchelli Station (geographic coordinates: 74.7°S, 164.1°E; corrected geomagnetic coordinates: 80.0°S, 306.8°E) and Dumont D’Urville (geographic coordinates: 66.7°S, 140.0°E; corrected geomagnetic coordinates: 80.4°S, 236.0°E) is shown. The analysis focuses on power spectra, coherence and phase difference between the stations, which are both located in the polar cap, with a 5-h magnetic local time displacement along a geomagnetic parallel; in this situation, the phase difference between geomagnetic fluctuations indicates the direction of their azimuthal propagation. Coherent fluctuations have been found to occur preferably when both stations are on the same side (dawnward or duskward) with respect to the polar cusp; moreover, around local magnetic midnight, they occur essentially during open magnetospheric conditions. The phase difference for coherent fluctuations indicates a propagation direction away from local geomagnetic noon and midnight. Also the analysis of three individual pulsation events, occurring at different times during the day, is shown; they are characterized at the two stations by simultaneous, coherent fluctuations, whose phase difference finds correspondence with the statistical behaviour.     

Putative graviperception mechanisms of protists.

Many (if not all) free-living cells use the gravity vector for their spatial orientation (gravitaxis). Additional responses may include gravikinesis as well as changes in morphological and physiological parameters. Though using essentially different modes of locomotion, ameboid and ciliated cells seem to rely on common fundamental graviperception mechanisms. Uniquely in the ciliate family Loxodidae a specialized intracellular gravireceptor organelle has been developed, whereas in all other cells common cell structures seem to be responsible for gravisensing. Changes in direction or magnitude of acceleration (from 0 to 5 g) as well as experiments in density-adjusted media strongly indicate that either the whole cytoplasm or dense organelles like nuclei act as statoliths and open directly or via cytoskeletal elements mechano-sensitive ion channels in the cell membrane. A recent spaceflight experiment (S/MM-06) demonstrated that prolonged (9 d) actual weightlessness did not affect the ability of Loxodes to respond to acceleration stimuli. However, prolonged cooling (> or = l4 d, 4-10 degrees C) destroyed the ability for gravitactic orientation of Paramecium. This may reflect a profound effect either on the gravireceptor itself or on the gravity-signal processing. In gravity signalling the ubiquitous second messenger cAMP may be involved in acceleration-stimulus transduction.     

Biological degradation and composition of inedible sweetpotato biomass.

Many challenges are presented by biological degradation in a bioregenerative Controlled Ecological Life Support System (CELSS) as envisioned by the U.S. National Aeronautics and Space Administration (NASA). In the studies conducted with biodegradative microorganism indigenous to sweetpotato fields, it was determined that a particle size of 75 microns and incubation temperature of 30 degrees C were optimal for degradation. The composition of the inedible biomass and characterization of plant nutrient solution indicated the presence of potential energy sources to drive microbial transformations of plant waste. Selected indigenous soil isolates with ligno-cellulolytic or sulfate-reducing ability were utilized in biological studies and demonstrated diversity in ability to reduce sulfate in solution and to utilize alternative carbon sources: a lignin analog--4-hydroxy, 3-methoxy cinnamic acid, cellulose, arabinose, glucose, sucrose, mannitol, galactose, ascorbic acid.     

Do we know the cosmic-ray boosters?

The literature on cosmic-ray acceleration tends to favour strong shocks (in supernovae, stellar and galactic winds) over compact boosters. Difficulties are posed by the spectrum which does not reveal the implied upper cutoff (at E = 10^13±1 eV), by the energy-dependent anisotropy at the high-energy end (at E 10¹⁸ eV), the missing hydrogen, the large required boosting efficiency, the high positron abundance at E 10 GeV, detailed studies of supernova shells, and by an inadequacy of the Sedov-Taylor model for supernova explosions. Solar and solar-wind data support single-step or few-step accelerations because of the large observed anisotropies and short time scales.

The importance of spindown in compact binary systems is often underestimated. Several neutron-star binaries have been detected at cosmic γ-ray energies. Cosmic-ray escape from the Galaxy may proceed supersonically through narrow tubes rather than via convective diffusion.     

Validation of University of New Brunswick Ionospheric Modeling Technique with ionosonde TEC estimation over South Africa

For more than a decade, ionospheric research over South Africa has been carried out using data from ionosondes geographically located at Madimbo (28.38°S, 30.88°E), Grahamstown (33.32°S, 26.50°E), and Louisvale (28.51°S, 21.24°E). The objective has been modelling the bottomside ionospheric characteristics using neural networks. The use of Global Navigation Satellite System (GNSS) data is described as a new technique to monitor the dynamics and variations of the ionosphere over South Africa, with possible future application in high frequency radio communication. For this task, the University of New Brunswick Ionospheric Modelling Technique (UNB-IMT) was applied to compute midday (10:00 UT) GNSS-derived total electron content (GTEC). GTEC values were computed using GNSS data for stations located near ionosondes for the years 2002 and 2005 near solar maximum and minimum, respectively. The GTEC was compared with the midday ionosonde-derived TEC (ITEC) measurements to validate the UNB-IMT results. It was found that the variation trends of GTEC and ITEC over all stations are in good agreement and show a pronounced seasonal variation for the period near solar maximum, with maximum values (∼80 TECU) around autumn and spring equinoxes, and minimum values (∼22 TECU) around winter and summer. Furthermore, the residual ΔTEC = GTEC − ITEC was computed. It was evident that ΔTEC, which is believed to correspond to plasmaspheric electron content, showed a pronounced seasonal variation with maximum values (∼20 TECU) around equinoxes and minimum (∼5 TECU) around winter near solar maximum. The equivalent ionospheric and total slab thicknesses were also computed and comprehensively discussed. The results verified the use of UNB-IMT as one of the tools for future ionospheric TEC research over South Africa.     

远东地区的微粒E层事件

本文给出了1983-1985年磁暴期间,我国乌鲁木齐等七个站及日本国分寺等五个站出现微粒E层的情况;得到了微粒E层的日变化、月变化和纬度变化;结合同时的地磁、宇宙线、TEC和电离层的变化,对微粒E层出现率作了分析。初步证实:微粒E层的形成和维持与赤道环电流指数(Dst)负变幅大小密切相关,此外还同宇宙线的FD(Forbushdecreases)事件的出现有关。作者认为,沉降粒子可能是低纬地区微粒E层事件的主要粒子来源。      

低纬电离层等离子体块相关等离子体泡演化期间的虚高变化

针对东亚地区地磁低纬度南北半球Vanimo台站(地理2.7°S,141.3°E;地磁11.2°S,146.2°W)和海南台站(地理19.5°N,109.1°E;地磁9.1°N,179.1°W)上空的3个电离层等离子体块与等离子体泡相关联的事件,利用地面台站的电离层测高仪连续观测数据,研究等离子体泡演化期间的电离层虚高变...     

Effects of temperature, CO2/O2 concentrations and light intensity on cellular multiplication of microalgae, Euglena gracilis.

Microalgae culture is likely to play an important role in aquatic food production modules in bioregenerative systems for producing feeds for fish, converting CO2 to O2 and remedying water quality as well as aquatic higher plants. In the present study, the effects of culture conditions on the cellular multiplication of microalgae, Euglena gracilis, was investigated as a fundamental study to determine the optimum culture conditions for microalgae production in aquatic food production modules including both microalgae culture and fish culture systems. E. gracilis was cultured under conditions with five levels of temperatures (25-33 degrees C), three levels of CO2 concentrations (2-6%), five levels of O2 concentrations (10-30%), and six levels of photosynthetic photon flux (20-200 micromoles m-2 s-1). The number of Euglena cells in a certain volume of solution was monitored with a microscope under each environmental condition. The multiplication rate of the cells was highest at temperatures of 27-31 degrees C, CO2 concentration of 4%, O2 concentration of 20% and photosynthetic photon flux of about 100 micromoles m-2 s-1. The results demonstrate that E. gracilis could efficiently produce biomass and convert CO2 to O2 under relatively low light intensities in aquatic food production modules.     

Complex organics in meteorites.

Complex macromolecular organic matter is present in carbonaceous chondrites as the most abundant organic matter and may be present in interstellar dusts and comets. With this view, our studies of the complex organic matter isolated from six CM2 chondrites, namely Yamato-74662, Yamato-791198, Yamato-793321, Yamato-86720, Belgica-7904, and Murchison are introduced and discussed in the text. The complex organic matter is acid-insoluble and organic solvent-insoluble, and therefore, it was examined by heating experiments to obtain information on its chemical constituents and characteristics. Three chondrites, Yamato-74662, Yamato-791198, and Murchison which have solvent-extractable organic compounds, such as amino acids, carboxylic acid, hydrocarbons, etc. possess thermally labile organic fraction in the complex organic matter. Organic compounds detected in the pyrolyzate of the complex organic matter number over 130 of which aromatic hydrocarbons are dominant. They appeared around 300 degrees C, and disappeared at about 600 degrees C with a maximum at 400-500 degrees C during the heating. On the other hand, the other three chondrites do not have the extractable organic compounds nor a thermally labile organic fraction. The presence or absence of the fraction in the complex organic matter likely indicates the presence or absence of the solvent-extractable organic compounds and relates to thermal history of the chondrite.     

Prostaglandin-induced radioprotection of murine intestinal crypts and villi by a PGE diene analog (SC-44932) and a PGI analog (iloprost).

The aminothiols exemplified by WR-2721 are effective radioprotectors; however, their toxicity associated with hypotension, nausea, and emesis has limited their development for applications to medicine or in harzardous radiation environments. There is a need for new radioprotectors that have fewer toxic side effects when given alone or combined with reduced amounts of thiols. A variety of prostaglandins (PGs) have been shown to be radioprotective agents and some appear to have fewer toxic side effects than the aminothiols. Iloprost, a stable PGI, analog protects the clonogenic epithelial cells of intestinal crypts but does not protect epithelial cells of the villi. In contrast, an E-series omega chain diene analog designated SC-44932 protects epithelial cells of both crypts and villi. When the two are combined, protection of the crypts is additive and the villi are protected to the same degree as when SC-44932 is given alone. Since radioprotection for some PGs has been shown to be dependent upon receptors, we suggest that the pattern of radioprotection seen with these two analogs depend on the location of the respective receptors or on the ability of differentiated villus cells to respond to PGs. By studying different analogs, we hope to identify mechanisms associated with PG-induced radioprotection and to identify the most protective PG analogs for applications of radioprotection.