Comprehensive data reduction package for the Immersion GRating INfrared Spectrograph: IGRINS

We present a Python-based data reduction pipeline package (PLP) for the Immersion GRating INfrared Spectrograph (IGRINS), an instrument that covers the complete H- and K-bands in one exposure with a spectral resolving power of 40,000. The reduction steps carried out by the PLP include flat-fielding, background removal, order extraction, distortion correction, wavelength calibration, and telluric correction using spectra of A type standard stars. As the spectrograph has no moving parts, the PLP automatically reduces the data using predefined functions for the processes of order extraction, distortion correction, and wavelength calibration. Before the telluric correction of the target spectra, the intrinsic hydrogen absorption features of the standard A star are removed with a Gaussian fitting algorithm. The final result is the flux of the target as a function of wavelength. Users can customize the predefined functions for the extraction of the spectrum from the echellogram and adjust the parameters for the fitting functions for the spectra of celestial objects, using “fine-tuning” options, as necessary. Presently, the PLP produces the best results for point-source targets.     

Modeling Multifractality of the Solar Wind

The question of multifractality is of great importance because it allows us to investigate interplanetary hydromagnetic turbulence. The multifractal spectrum has been investigated with Voyager (magnetic field) data in the outer heliosphere and with Helios (plasma) data in the inner heliosphere. We use the Grassberger and Procaccia method that allows calculation of the generalized dimensions of the solar wind attractor in the phase space directly from the cleaned experimental signal. We analyze time series of plasma parameters of the low-speed streams of the solar wind measured in situ by Helios in the inner heliosphere. The resulting spectrum of dimensions shows a multifractal structure of the solar wind attractor. In order to quantify that multifractality, we use a simple analytical model of the dynamical system. Namely, we consider the generalized self-similar baker’s map with two parameters describing uniform compression and natural invariant measure on the attractor of the system. The action of this map exhibits stretching and folding properties leading to sensitive dependence on initial conditions. The obtained solar wind singularity spectrum is consistent with that for the multifractal measure on the weighted baker’s map.     

Emesis and space motion sickness in amphibians.

Amphibians possess the ability to vomit in response to a variety of stimuli that provoke emesis in mammals. Pharmacological studies have establish that the ejection of gastric contents and the basic mechanism for vomiting have been phylogenetically conserved among these tetrapods. As part of on-going comparative studies on emesis in vertebrates, we previously documented that some postmetamorphic anurans and salamander larvae experience motion-induced emesis when exposed to the provocative stimulus of parabolic aircraft flight. However, more recent experiments suggest that there are strict conditions for inducing emesis in amphibians exposed to parabolic flight and that amphibians are not as sensitive to this stimulus as mammals. Further studies on emesis in lower vertebrates may help us understand the processes that cause emesis in abnormal gravitational regimes.     

The mechanics of air-breathing in anuran larvae: implications to the development of amphibians in microgravity.

Because of their rapid development, amphibians have been important model organisms in studies of how microgravity affects vertebrate growth and differentiation. Both urodele (salamanders) and anuran (frogs and toads) embryos have been raised in orbital flight, the latter several times. The most commonly reported and striking effects of microgravity on tadpoles are not in the vestibular system, as one might suppose, but in their lungs and tails. Pathological changes in these organs disrupt behavior and retard larval growth. What causes malformed (typically lordotic) tadpoles in microgravity is not known, nor have axial pathologies been reported in every flight experiment. Lung pathology, however, has been consistently observed and is understood to result from the failure of the animals to inflate their lungs in a timely and adequate fashion. We suggest that malformities in the axial skeleton of tadpoles raised in microgravity are secondary to problems in respiratory function. We have used high speed videography to investigate how tadpoles breathe air in the 1G environment. The video images reveal alternative species-specific mechanisms, that allow tadpoles to separate air from water in less that 150 ms. We observed nothing in the biomechanics of air-breathing in 1G that would preclude these same mechanisms from working in microgravity. Thus our kinematic results suggest that the failure of tadpoles to inflate their lungs properly in microgravity is due to the tadpoles' inability to locate the air-water interface and not a problem with the inhalation mechanism per se.     

Gravitropism of basidiomycetous fungi--on Earth and in microgravity.

In order to achieve perfect positioning of their lamellae for spore dispersal, fruiting bodies of higher fungi rely on the omnipresent force gravity. Only accurate negatively gravitropic orientation of the fruiting body cap will guarantee successful reproduction. A spaceflight experiment during the STS-55 Spacelab mission in 1993 confirmed that the factor gravity is employed for spatial orientation. Most likely every hypha in the transition zone between the stipe and the cap region is capable of sensing gravity. Sensing presumably involves slight sedimentation of nuclei which subsequently causes deformation of the net-like arrangement of F-actin filament strands. Hyphal elongation is probably driven by hormone-controlled activation and redistribution of vesicle traffic and vesicle incorporation into the vacuoles and cell walls to subsequently cause increased water uptake and turgor pressure. Stipe bending is achieved by way of differential growth of the flanks of the upper-most stipe region. After reorientation to a horizontal position, elongation of the upper flank hyphae decreases 40% while elongation of the lower flank slightly increases. On the cellular level gravity-stimulated vesicle accumulation was observed in hyphae of the lower flank.     

A capillary-driven root module for plant growth in microgravity.

A new capillary-driven root module design for growing plants in microgravity was developed which requires minimal external control. Unlike existing systems, the water supply to the capillary-driven system is passive and relies on root uptake and media properties to develop driving gradients which operate a suction-induced flow control valve. A collapsible reservoir supplies water to the porous membrane which functions to maintain hydraulic continuity. Sheet and tubular membranes consisting of nylon, polyester and sintered porous stainless steel were tested. While finer pore sized membranes allow greater range of operation, they also reduce liquid flux thereby constraining system efficiency. Membrane selection should consider both the maximum anticipated liquid uptake rate and maximum operating matric head (suction) of the system. Matching growth media water retention characteristics to the porous membrane characteristics is essential for supplying adequate liquid flux and gas exchange. A minimum of 10% air-filled porosity (AFP) was necessary for adequate aeration. The capillary-driven module maintained hydraulic continuity and proper gas exchange rates for more than 80 days in a plant growth experiment.     

Biodosimetry of heavyions by interphase chromosome painting

We report measurements of chromosomal aberrations in peripheral blood lymphocytes from cancer patients undergoingradiotherapy treatment. Patients with cervix or esophageal cancer were treated with 10 MV X-rays produced at a LINAC accelerator, or high-energy carbon ions produced at the HIMAC accelerator at the National Institute for Radiological Sciences (NIRS) in Chiba. Blood samples were obtained before, during, and after the radiation treatment. Chromosomes were prematurely condensed by incubation in calyculin A. Aberrations in chromosomes 2 and 4 were scored after fluorescence in situ hybridization with whole-chromosome probes. Pre-treatment samples were exposed in vitro to X-rays, individual dose-response curves for the induction of chromosomal aberrations were determined, and used as calibration curves to calculate the effective whole-body dose absorbed during the treatment. This calculated dose, based on the calibration curve relative to the induction of reciprocal exchanges, has a sharp increase after the first few fractions of the treatment, then saturates at high doses. Although carbon ions are 2–3 times more effective than X-rays in tumor sterilization, the effective dose was similar to that of X-ray treatment. However, the frequency of complex-type chromosomal exchanges was much higher for patients treated with carbon ions than X-ray.     

Observations in the South Atlantic geomagnetic anomaly with intercosmos-Bulgaria-1300 during a geomagnetic storm

The region of South Atlantic Geomagnetic Anomaly (SAGA) was investigated by the Intercosmos-Bulgaria-1300 satellite, launched on August 7, 1981. On the basis of data obtained from 15 orbits during increased geomagnetic activity in August 1981, a map of the Anomaly was elaborated. Two centres of activity were identified. By means of the EMO-5 electrophotometer on board the Intercosmos-Bulgaria-1300 satellite, the atmosphere glow in lines λ 5577 Å, λ 6300 Å and λ 4278 Å was studied.     

The biological clock of Neurospora in a microgravity environment.

The circadian rhythm of conidiation in Neurospora crassa is thought to be an endogenously derived circadian oscillation; however, several investigators have suggested that circadian rhythms may, instead, be driven by some geophysical time cue(s). An experiment was conducted on space shuttle flight STS-9 in order to test this hypothesis; during the first 7-8 cycles in space, there were several minor alterations observed in the conidiation rhythm, including an increase in the period of the oscillation, an increase in the variability of the growth rate and a diminished rhythm amplitude, which eventually damped out in 25% of the flight tubes. On day seven of flight, the tubes were exposed to light while their growth fronts were marked. Some aspect of the marking process reinstated a robust rhythm in all the tubes which continued throughout the remainder of the flight. These results from the last 86 hours of flight demonstrated that the rhythm can persist in space. Since the aberrant rhythmicity occurred prior to the marking procedure, but not after, it was hypothesized that the damping on STS-9 may have resulted from the hypergravity pulse of launch. To test this hypothesis, we conducted investigations into the effects of altered gravitational forces on conidiation. Exposure to hypergravity (via centrifugation), simulated microgravity (via the use of a clinostat) and altered orientations (via alterations in the vector of a 1 g force) were used to examine the effects of gravity upon the circadian rhythm of conidiation.     

Biological nitrogen fixation under primordial Martian partial pressures of dinitrogen.

Early Earth and early Mars were similar enough such that past geochemical and climatic conditions on Mars may have also been favorable for the origin of life. However, one of the most striking differences between the two planets was the low partial pressure of dinitrogen (pN2) on early Mars (18 mb). On Earth, nitrogen is a key biological element and in many ecosystems the low availability of fixed nitrogen compounds is the main factor limiting growth. Biological fixation of dinitrogen on Earth is a crucial source of fixed nitrogen. Could the low availability of dinitrogen in the primordial Martian atmosphere have prevented the existence, or evolution of Martian microbiota? Azotobacter vinelandii and Azomonas agilis were grown in nitrogen free synthetic medium under various partial pressures of dinitrogen ranging from 780-0 mb (total atmosphere=1 bar). Below 400 mb the biomass, cell number, and growth rate decreased with decreasing pN2. Both microorganisms were capable of growth at a pN2 as low as 5 mb, but no growth was observed at a pN2 < or = 1 mb. The data appear to indicate that biological nitrogen fixation could have occurred on primordial Mars (pN2=18 mb) making it possible for a biotic system to have played a role in the Martian nitrogen cycle. It is possible that nitrogen may have played a key role in the early evolution of life on Mars, and that later a lack of available nitrogen on that planet (currently, pN2=0.2 mb) may have been involved in its subsequent extinction.