Annual solar UV exposure and biological effective dose rates on the Martian surface.

The ultraviolet (UV) environment of Mars has been investigated to gain an understanding of the variation of exposure throughout a Martian year, and link this flux to biological effects and possible survival of organisms at the Martian surface. To gain an idea of how the solar UV radiation varies between different regions, including planned landing sites of two future Mars surface missions, we modelled the total solar UV surface flux throughout one Martian year for two different dust scenarios. To understand the degree of solar UV stress on micro-organisms and/or molecules essential for life on the surface of Mars, we also calculated the biologically effective dose (BED) for T7 and Uracil in relevant wavelength regions at the Martian surface as a function of season and latitude, and discuss the biological survival rates in the presence of Martian solar UV radiation. High T7/Uracil BED ratios indicate that even at high latitudes where the UV flux is significantly reduced, the radiation environment is still hostile for life due to the persisting UV-C component of the flux.     

Residual chromatin breaks as biodosimetry for cell killing by carbon ions

We have studied the relationship between cell killing and the induction of residual chromatin breaks on various human cell lines and primary cultured cells obtained by biopsy from patients irradiated with either X-rays or heavy-ion beams to identify potential bio-marker of radiosensitivity for radiation-induced cell killing. The carbon-ion beams were accelerated with the Heavy Ion Medical Accelerator in Chiba (HIMAC). Six primary cultures obtained by biopsy from 6 patients with carcinoma of the cervix were irradiated with two different mono-LET beams (LET= 13 keV/μm, 76 keV/μm) and 200kV X rays. Residual chromatin breaks were measured by counting the number of non-rejoining chromatin fragments detected by the premature chromosome condensation (PCC) technique after a 24 hour postirradiation incubation period. The induction rate of residual chromatin breaks per cell per Gy was the highest for 76 keV/μm beams on all of the cells. Our results indicated that cell which was more sensitive to the cell killing was similarly more susceptible to induction of residual chromatin breaks. Furthermore there is a good correlation between these two end points in various cell lines and primary cultured cells. This suggests that the detection of residual chromatin breaks by the PCC technique may be useful as a predictive assay of tumor response to cancer radiotherapy.     

Seasonal-to-interannual variability of chlorophyll-a bloom timing associated with physical forcing in the Gulf of Cádiz

Seasonal-to-interannual variability of the winter-spring bloom in the Gulf of Cádiz, eastern North Atlantic, has been investigated using chlorophyll-a remote sensing (CHL). These data have been obtained from the GlobColour project; the temporal coverage extends from September 1997 to December 2010. In this study we develop a generic quantitative approach for describing the temporal variability in the shape of the winter-spring bloom within a region. Variability in both the timing and magnitude of the bloom in the basin has been evaluated as a function of physical properties in the water column such as Mixed Layer Depth (MLD, GODAS model), sea surface temperature (SST, from AVHRR radiometers), photosynthetically-active radiation (PAR, from ocean color data) and euphotic depth (Z_eu, from ocean color data). The analysis indicated that the timing, size and duration of the phytoplankton bloom in this area are largely controlled by both meteorological and oceanographic conditions at different scales; this means that it is likely to vary widely from one year to another.     

A debris image tracking using optical flow algorithm

This study proposes a motion detection and object tracking technique for GEO debris in a sequence of images. A couple of techniques (called the “stacking method” and “line-identifying technique”) were recently proposed to address the same problem. Although these techniques are effective at detecting the debris position and motion in the image sequences, there are some issues concerned with computational load and assumed debris motion. This study derives a method to estimate motion vectors of objects in image sequence and finally detect the debris locations by using a computer vision technique called an optical flow algorithm. The new method detects these parameters in low computational time in a serial manner, which implies that it has an advantage to track not only linear but also nonlinear motion of GEO debris more easily than the previous methods. The feasibility of the proposed methods is validated using real and synthesized image sequences which contain some typical debris motions.     

Comparison of Antarctic riometer radio wave absorption and THEMIS mission energetic electron fluxes

Simultaneous observations of in situ plasma properties in the tail of the Earth’s magnetosphere and of ground based instruments, lying on the same geomagnetic field lines, have recently proved to yield significant new results. In most cases magnetosphere ionosphere interactions during the night-time northern hemisphere conditions are studied. Here, observations of energetic electrons in the tail of the Earth’s magnetosphere made by the THEMIS mission satellites are compared with auroral radio wave absorption determined by riometers in the Antarctic for sunlit conditions. Days for which satellites and riometers are connected by the same geomagnetic field line are selected using a geomagnetic field model. The six days analysed show clear associations between fluxes and absorptions in some cases. However, these do not necessarily correspond to conjugacy intervals. Hours of positive associations are 1.65 times those for negative associations, all hours and days considered (1.42–3.6 on five days and 0.58 on the other day). These computations are assumed appropriate since the footprints of the satellites used approximately follow corrected geomagnetic parallels for all six days studied. The use of a finer parameterization of geomagnetic models to determine conjugacy may be needed.     

Relativistic electron fluxes and dose rate variations during April–May 2010 geomagnetic disturbances in the R3DR data on ISS

Space radiation has been monitored successfully using the Radiation Risks Radiometer-Dosimeter (R3D) installed at the ESA EXPOSE-R (R3DR) facility outside of the Russian Zvezda module of the International Space Station (ISS) between March 2009 and January 2011. R3DR is a Liulin type spectrometer–dosimeter with a single Si PIN detector 2 cm² of area and 0.3 mm thick. The R3DR instrument accumulated about 2 million measurements of the absorbed dose rate and flux of 10 s resolution. The total external and internal shielding before the detector of R3DR device is 0.41 g cm⁻². The calculated stopping energy of normally incident particles to the detector is 0.78 MeV for electrons and 15.8 MeV for protons. After the Coronal Mass Ejection (CME) at 09:54 UTC on 3 April 2010, a shock was observed at the ACE spacecraft at 0756 UTC on 5 April, which led to a sudden impulse on Earth at 08:26 UTC. Nevertheless, while the magnetic substorms on 5 and 6 of April were moderate; the second largest in history of GOES fluence of electrons with energy >2 MeV was measured. The R3DR data show a relatively small amount of relativistic electrons on 5 April. The maximum dose rate of 2323 μGy day⁻¹ was reached on 7 April; by 9 April, a dose of 6600 μGy was accumulated. By the end of the period on 7 May 2010 a total dose of 11,587 μGy was absorbed. Our data were compared with AE-8 MIN, CRESS and ESA-SEE1 models using SPENVIS and with similar observations on American, Japanese and Russian satellites.     

An ion analyzer for the lunar surface with E-parallel–B

We present a novel instrument concept to measure the energy and mass spectra of ions incident on the lunar surface, based on the E-parallel–B or Thomson-parabola device used extensively as a diagnostic in the plasma fusion community. The Apollo-era Suprathermal Ion Detector Experiment (SIDE) was the first instrument package to perform in-situ measurements of ions incident on the lunar surface. The ions can originate from a variety of sources, including the solar wind, the Earth’s magnetotail, and photoionization of the thin lunar atmosphere. The species and energy distribution of ions arriving at the lunar surface depend in a complicated and poorly-understood fashion on the phase of the lunar day, the position of the Moon with respect to the Earth, and on the local plasma environment.     

Analysis of data of “Clementine” and “KAGUYA” missions and “ULCN” and “KSC-1162” catalogues

In this paper an analysis of data coordinate systems from selenographic catalogues and space missions was carried out. The lunar macrorelief models were made on basis of the software package ASNI USTU using method of the spherical harmonic expansion. These models accurately describe the global features of the lunar figure. To construct these models the following sources of topographic information were used: “Clementine” and “KАGUYА” (Selena, Japan mission) missions, “KSC-1162” (Kazan selenocentric catalogue), “Kiev” (selenodesic catalogue), “SAI” (Chuikova (1975)), “Bills, Ferrari”, “ULCN” (The Unified Lunar Control Network 2005). Direct comparison hypsometric information “KSС-1162” catalogue data with “Clementine” mission was carried out. These researches confirmed a good agreement of the hypsometric information of compared systems. The normalized coefficients were obtained on basis of the hypsometric information expansion for eight sources. The displacement of the lunar center of mass (LCM) relatively to the lunar center of figure (LCF) was obtained by using topographic data selenodetical catalogues and space missions.     

Soybean cultivar selection for Bioregenerative Life Support Systems (BLSSs) – Hydroponic cultivation

Four soybean cultivars (‘Atlantic’, ‘Cresir’, ‘Pr91m10’ and ‘Regir’), selected through a theoretical procedure as suitable for cultivation in BLSS, were evaluated in terms of growth and production. Germination percentage and Mean Germination Time (MGT) were measured. Plants were cultivated in a growth chamber equipped with a recirculating hydroponic system (Nutrient Film Technique). Cultivation was performed under controlled environmental conditions (12 h photoperiod, light intensity 350 μmol m⁻² s⁻¹, temperature regime 26/20 °C light/dark, relative humidity 65–75%). Fertigation was performed with a standard Hoagland solution, modified for soybean specific requirements, and EC and pH were kept at 2.0 dS m⁻¹ and 5.5 respectively.     

Introduction: an overview of gravity sensing, perception, and signal transduction in animals and plants.

The antiquity of biological sensitivity and response to gravity can be traced through the ubiquity of morphology, mechanisms, and cellular events in gravity sensing biological systems in the most diverse species of both plants and animals. Further, when we examine organisms at the cellular level to elucidate the molecular mechanism by which a gravitational signal is transduced into a biochemical response, the distinction between plants and animals becomes blurred.