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PubMed2003

Practical algorithm for reducing convex spike noises on a spectrum.

Quantitative data analysis and high-sensitivity measurements by use of Raman and infrared spectroscopy often suffer from noisy spikes such as those due to cosmic rays and water vapor. Since these spikes are unidirectional and isolated, the conventional smoothing techniques do a poor job of removing them. However, a small modification can improve these smoothing techniques significantly. In this paper, we present a simple denoising technique for a single-scan spectrum that is corrupted by convex spikes. In general, the noisy spikes arising from cosmic rays or water vapor have a much narrower bandwidth compared with target "informative" bands in Raman and infrared spectra. This means that these noisy spikes can be separated from the target bands by means of the difference in the bandwidths. The proposed method employs the moving window averaging procedure to distinguish and separate the convex spike. The proposed algorithm allows us to take away the convex spikes from measured spectra without preparing multiply recorded spectra and (much) biasing the measured spectrum.

Acetamides↗
PubMed2003

Image curvature correction and cosmic removal for high-throughput dispersive Raman spectroscopy.

A key factor determining the sensitivity of a Raman spectrometer is the usable detection area, which is the product of the usable slit width and the height. For the majority of process Raman samples, the larger the sampling area is, the more the scattered Raman signal can be gathered. On a multi-channel-detector-based dispersive spectrometer, a given spectral resolution limits the slit width. Extending the slit height using a straight slit usually causes the image to be curved on the detector due to optical effects. If left untreated, the curved slit image will degrade the peak shape and spectral resolution; therefore, the slit height must also be kept small if this negative effect is to be avoided. The mechanism of the curvature formation was analyzed for an on-axis-lens-based spectrograph, and a correction technique was developed to generate a straight slit image on the charge-coupled device (CCD). This allowed a large portion of the CCD height to be used without degrading the spectral resolution. A large fiber bundle was usable instead of a single small core fiber, generating significant increase in collected signal strength in clear or translucent samples. The straight image also enabled a new cosmic spike removal method, wherein the CCD image was divided into multiple strips, and a comparison among them allowed the identification and removal of cosmic spikes in a single CCD integration. On the contrary, many existing cosmic removal methods rely on comparison of multiple sequentially acquired spectra, potentially introducing artifacts, particularly when the spectral features are changing.

Acetaminophen↗
PubMed2000

Correlation of two levels of space proton flux with monthly distribution of deaths from cardiovascular disease and suicide.

In our previous studies /1-3/ we described some significant links between monthly number of deaths due to cardiovascular disease and suicide and space proton flux > 90 MeV. The aims of the present study were to compare the relationship of some solar and geomagnetic parameters with space proton fluxes of > 60 and > 90 MeV; to examine the monthly correlation of these two proton groups with the monthly death distribution in two countries, Israel and Lithuania. Physical data were obtained from the National Geophysical Data Center and the SESC in Boulder, CO; NSSDC in Goddard Space Flight Center, USA, and the Izmiran Institute of the Academy of Sciences in Russia. Pearson correlation coefficients and probabilities were compared for 56-180 consecutive months. Proton flux of > 60 MeV significantly correlated with three of the four studied monthly geomagnetic activity indices (Ap, Am, Dst), but not with such solar activity markers as sunspot number and solar flux (2800 MGH, 10.6 cm). There was no significant relationship between proton flux of > 60 MeV and monthly number of deaths from cardiovascular diseases and suicide, in contrast to the results for > 90 MeV. From the data available during the 36 months (1986-1988), there was no correlation between monthly levels of > 60 to > 90 MeV. In conclusion, a monthly space proton flux of > 60 MeV is not significantly correlated with the monthly death distribution from cardiovascular disease and suicide and some solar activity indices, such as proton flux of > 90 MeV. It is possible that the 60-90 MeV fraction in the > 60 MeV proton flux "blunts" the cosmobiological relationship between proton flux of > 90 MeV and monthly death number.

Cardiovascular Diseases↗
PubMed2002

Cosmic rays activity and monthly number of deaths: a correlative study.

We studied the relation between the intensity of cosmic rays, the level of solar/geomagnetic activity, and the monthly numbers of deaths in a large hospital in Israel and in all Lithuania. The Israeli data include 30526 hospital deaths, two groups of fatal suicides (2359, 2763), and 15435 suicidal attempts for two periods of 108 and 236 consecutive months. The national data for the entire Republic of Lithuania include 424925 deaths for the period of 120 consecutive months. Cosmic rays intensity was measured by an Apatity neutron monitor. We obtained the data on solar, geomagnetic radiovawe propagation, ionosphere ionization hours, proton flux of two energy levels (>90 and 60 MeV) from the National Geophysical Data Center at Goddard Space Flight Center, National Space Environment Center at Boulder, Colorado, USA, and from the Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation (IZMIRAN), Russia. We calculated Pearson coefficients and their probabilities for correlation between monthly space activity level and monthly number of male and female deaths from different causes. Cosmic rays activity revealed significant negative correlation with solar/geomagnetic activity indices and related physical phenomena levels. This activity strongly correlated with flux of protons with the energies >90 MeV proton flux and did not exhibit significant correlation with 60 MeV proton fluxes. Cosmic rays intensity correlation with monthly numbers of deaths was strong for noncardiovascular deaths, suicides, and traffic accidents. The correlation was much weaker for deaths caused by ishemic heart disease and strokes.

Accidents↗
PubMed2003

Temporal distribution of death among oncology patients: environmental links.

BACKGROUND: The natural history of terminal oncologic disease is death from cardiopulmonary arrest. The goal of this study was to determine whether the temporal distribution of death among oncology patients is related to levels of environmental physical activity-solar, geomagnetic, and cosmic rays and high energy space proton flux, as previously shown for other situations like accidents, suicide, and the occurrence of acute myocardial infarction. EXPERIMENTAL: Deaths of oncology patients, n = 102604, in 168 consecutive months were compared with-monthly indices of solar, geomagnetic, cosmic rays activity (sunspot number, solar flux, Ap, Cp, Am), and indices of magnetic and cosmic rays activity according to neutron monitor data). In addition, oncology patients monthly death numbers were compared with numbers of deaths from ischemic heart disease (IHD), stroke, sudden cardiac death (SCD), accidents, road accidents, non cardiovascular death (total deaths - [IHD + stroke]). The National Data of the Republic of Lithuania was used, excluding SCD and myocardial infarction in Kaunas--the second largest city in Lithuania Monica study register was used for SCD at age 25-64, and all data of AMI. Pearson correlation coefficients and their probabilities were obtained between the numbers of oncology patient monthly deaths and (1) cosmo-physical indices and (2) the number of deaths from other causes and the occurrence of AMI. RESULTS: The number of oncology patient deaths was inversely correlated with solar and geomagnetic activity indices and positively correlated with cosmic rays activity. The number of oncology patient deaths was correlated with monthly number of deaths from non-cardiovascular courses, stroke, suicide, at trend level with SCD, but not with deaths from IHD, accidents, road accidents. Oncology patient deaths showed a significant correlation with the number of AMI. CONCLUSION: The monthly death number of oncology patients is significantly related with environmental physical activity and shows similarity with deaths distribution by time of some other groups of death--stroke, SCD, suicide, and occurrence of AMI. The inverse correlation with solar and geomagnetic activity and positive links with cosmic rays activity level are remarkable.

Accidents↗
PubMed2004

Link between monthly rates of four subtypes of acute myocardial infarction and their corresponding cosmophysical activity parameters.

UNLABELLED: The aim of this study was (1) to examine the relation between the monthly rate of acute myocardial infarction (AMI) and three cosmophysical activity parameters: solar activity (SA), geomagnetic activity (GMA), and cosmic rays activity (CRA) levels; (2) to study whether different subtypes of AMI: ST-elevation MI (STEMI), non-ST-elevation (NSTEMI), Q-wave (Q-waveMI) and non-Q-wave (NQ-wave MI) are linked with monthly cosmophysical indices or with the daily level (I degrees-IV degrees) of GMA. METHODS: For the first question, we studied for 204 consecutive months (1983-1999) 16,683 patients (including 10405 males) with AMI who were included in the Kaunas Registry and for the second, 3824 AMI patients (2342 males), 72-month data. Cosmophysical data were obtained from the Apatity Neutron Monitoring Station of the Russian Academy of Science. RESULTS: According to neutron monitoring data, total AMI and all its subtypes significantly correlated with monthly levels of CRA and inversely correlated with SA and GMA indices (r = 0.32-0.45; p = 0.0007-0.0001). No significant correlation was found between AMI subtypes and the daily level (I degrees-IV degrees) of GMA. All cosmophysical parameters were stronger in female patients. CONCLUSION: The monthly rates of all subtypes of AMI were significantly correlated with CRA and inversely correlated with SA and GMA, more strongly in female patients. We presume that the environmental factors studied here affect the general patho-physiological components of AMI, and that different subtypes are a consequence of the localization and extent of the process.

Adult↗
PubMed2006

Neutrons and sudden cardiac death (SCD) codes 121-125 ICD 10.

Recent studies have shown that (1) monthly neutron activity (NA) (imp/min) correlates with monthly number of acute myocardial infarction (AMI); (2) NA is higher on days of automatic implantable cardioverter defibrillators (AICD) discharges for VT, VF. Here we checked the level of NA in relation to timing and type of sudden cardiac death (SCD) patients [n=848 (579, 68.28% male)] obtained from the Kaunas registry for the years 2002-2004. All underwent Forensic Medicine post mortem examination and classification according to ICD10 by code 121-125. Daily NA data were obtained from Oulu U-ty, Finland and Moscow Monitoring Station of the Russian Academy of Sciences. No difference in NA was found on days with or without SCD. In men < 65, SCD occurred on days with higher NA than in women of the same age (p = 0.01) or in > 65 y old men (p = 0.045). Days of SCD with myocardial ruptures showed the highest level of NA, significantly higher than on all days (n = 669) of SCD (p = 0.037) and all 1096 days of the study (p = 0.0048). Three groups were accompanied by significantly higher NA: repeated AMI, myocardial ruptures (codes122, 123), and coronary atherothrombosis without AMI, related to electrical heart instability. The mechanism of possible neutron role in pathophysiology needs special studies.

Adult↗
PubMed2001

Comparisons of LET distributions measured in low-earth orbit using tissue-equivalent proportional counters and the position-sensitive silicon-detector telescope (RRMD-III).

Determinations of the LET distribution, phi(L), of charged particles within a spacecraft in low-Earth orbit have been made. One method used a cylindrical tissue-equivalent proportional counter (TEPC), with the assumption that for each measured event, lineal energy, y, is equal to LET and thus phi(L) = phi(y). The other was based on the direct measurement of LETs for individual particles using a charged-particle telescope consisting of position-sensitive silicon detectors called RRMD-III. There were differences of up to a factor of 10 between estimates of phi(L) using the two methods on the same mission. This caused estimates of quality factor to vary by a factor of two between the two methods.

Cosmic Radiation↗
PubMed2001

Preface.

Explore the source record for details and available documents.

Aerospace Medicine↗
PubMed2006

Analytical functions to predict cosmic-ray neutron spectra in the atmosphere.

Estimation of cosmic-ray neutron spectra in the atmosphere has been an essential issue in the evaluation of the aircrew doses and the soft-error rates of semiconductor devices. We therefore performed Monte Carlo simulations for estimating neutron spectra using the PHITS code in adopting the nuclear data library JENDL-High-Energy file. Excellent agreements were observed between the calculated and measured spectra for a wide altitude range even at the ground level. Based on a comprehensive analysis of the simulation results, we propose analytical functions that can predict the cosmic-ray neutron spectra for any location in the atmosphere at altitudes below 20 km, considering the influences of local geometries such as ground and aircraft on the spectra. The accuracy of the analytical functions was well verified by various experimental data.

Algorithms↗
PubMed1998

Abiotic formation of bioorganic compounds in space--preliminary experiments on ground and future exobiology experiments in space.

Simulation experiments on ground have shown that "amino acid precursors", which give amino acids after acid-hydrolysis, can be formed when an ice mixture simulating ice mantles of interstellar dust particles (lSDs) is irradiated with high energy particles or UV light. It is strongly suggested that such bioorganic compounds were delivered by comets for the first biosphere on the Earth. It is of great interest to confirm this hypothesis in actual space conditions, such as in an exposed facility of JEM. Fundamental designs for such exobiology experiments in earth orbit (EEEO) will be discussed.

Amino Acids↗
PubMed1998

A conceptual design for cosmo-biology experiments in Earth's Orbit.

A conceptual design was developed for a cosmo-biology experiment. It is intended to expose simulated interstellar ice materials deposited on dust grains to the space environment. The experimental system consists of a cryogenic system to keep solidified gas sample, and an optical device to select and amplify the ultraviolet part of the solar light for irradiation. By this approach, the long lasting chemical evolution of icy species could be examined in a much shorter time of exposure by amplification of light intensity. The removal of light at longer wavelength, which is ineffective to induce photochemical reactions, reduces the heat load to the cryogenic system that holds solidified reactants including CO as a constituent species of interstellar materials. Other major hardware components were also defined in order to achieve the scientific objectives of this experiment. Those are a cold trap maintained at liquid nitrogen temperature to prevent the contamination of the sample during the exposure, a mechanism to exchange multiple samples, and a system to perform bake-out of the sample exposure chamber. This experiment system is proposed as a candidate payload implemented on the exposed facility of Japanese Experiment Module on International Space Station.

Cold Temperature↗
PubMed1998

Ecological cultivation ark (ECA) project--mutation and evolution of micro-organisms in space.

Ecological cultivation capsules (ECC), that is a materially sealed microcosm. composed of primary producers, consumers and bacteria as a decomposer were developed in order to cultivate bacteria without any artificial operation for long duration more than 10 years in space. It is planned to be left on the space station to study the process that bacteria in MIR space station had acquired their resistance to cosmic ray radiation as well as ultra-violet light. As contrasted with the space experiment, bacteria are cultivating in the ECC on the ground to trace the changes of bacteria under the simulated radiation dose in Earth orbit.

Bacillus subtilis↗
PubMed1998

Corona chemistry in Titan.

The atmosphere of Titan is constantly bombarded by galactic cosmic rays and Saturnian magnetospheric electrons causing the formation of free electrons and primary ions, which are then stabilized by ion cluster formation and charging of aerosols. These charged particles accumulate in drops in cloud regions of the troposphere. Their abundance can substantially increase by friction, fragmentation or collisions during convective activity. Charge separation occurs with help of convection and gravitational settling leading to development of electric fields within the cloud and between the cloud and the ground. Neutralization of these charged particles leads to corona discharges which are characterized by low current densities. We have therefore, experimentally studied the corona discharge of a simulated Titan's atmosphere (10% methane and 2% argon in nitrogen) at 500 Torr and 298 K by GC-FTIR-MS techniques. The main products have been identified as hydrocarbons (ethane, ethyne, ethene, propane, propene+propyne, cyclopropane, butane, 2-methylpropane, 2-methylpropene, n-butane, 2-butene, 2,2-dimethylpropane, 2-methylbutane, 2-methylbutene, n-pentane, 2,2-dimethylbutane, 2-methylpentane, 3-methylpentane, n-hexane, 2,2-dimethylhexane, 2,2-dimethylpentane, 2,2,3-trimethylbutane, 2,3-dimethylpentane and n-heptane), nitriles (hydrogen cyanide, cyanogen, ethanenitrile, propanenitrile, 2-methylpropanenitrile and butanenitrile) and a highly branched hydrocarbon deposit. We present the trends of hydrocarbons and nitriles formation as a function of discharge time in an ample interval and have derived their initial yields of formation. The results clearly demonstrate that a complex organic chemistry can be initiated by corona processes in the lower atmosphere. Although photochemistry and charged particle chemistry occurring in the stratosphere can account for many of the observed hydrocarbon species in Titan, the predicted abundance of ethene is too low by a factor of 10 to 40. While some ethene will be produced by charged-particle chemistry, the production of ethene by corona processes and its subsequent diffusion into the stratosphere appears to be an adequate source. Because little UV penetrates to the lower atmosphere to destroy the molecules formed there, the corona-produced species may be long-lived and contribute significantly to the composition of the lower atmosphere and surface.

Aerosols↗