Laboratory modeling of nonstationary processes in space cyclotron masers: First results and prospects

Results are presented from laboratory modeling of the dynamics of space cyclotron masers. A selfoscillatory mode of cyclotron instability in the nonequilibrium plasma of an ECR discharge in a magnetic mirror trap is found. The plasma comprises two electron populations: the background population with a density of N _e ～ 10¹³–10¹⁴ cm^?3 and temperature of T _e ≈ 300 eV and the energetic population with a density of N _e ～ 10¹⁰ cm^?3 and temperature of T _e ≈ 10 keV. Quasi-periodic pulsed precipitation of energetic electrons from the trap, accompanied by microwave bursts at frequencies below the electron gyrofrequency in the center of the trap, is detected. The study of the microwave plasma emission and the energetic electrons precipitated from the trap shows that the precipitation is related to the excitation of whistler-mode waves propagating nearly parallel to the trap axis. The observed instability has much in common with phenomena in space magnetic traps, such as radiation belts of magnetized planets and solar coronal loops. The experimental results demonstrate the opportunity of laboratory modeling of space cyclotron masers. The main tasks and possibilities of such modeling are discussed.     

Solitary waves in dusty plasmas with weak relativistic effects in electrons and ions

Two distinct classes of dust ion acoustic (DIA) solitary waves based on relativistic ions and electrons, dust charge Z _d and ion-to-dust mass ratio Q’ = m _i /m _d are established in this model of multicomponent plasmas. At the increase of mass ratio Q’ due to increase of relativistic ion mass and accumulation of more negative dust charges into the plasma causing decrease of dust mass, relativistic DIA solitons of negative potentials are abundantly observed. Of course, relativistic compressive DIA solitons are also found to exist simultaneously. Further, the decrease of temperature inherent in the speed of light c causes the nonlinear term to be more active that increases the amplitude of the rarefactive solitons and dampens the growth of compressive solitons for relatively low and high mass ratio Q’, respectively. The impact of higher initial streaming of the massive ions is observed to identify the point of maximum dust density N _d to yield rarefactive relativistic solitons of maximum amplitude.     

Informative Value of Temperatures in Different Areas of the Human Body for Correcting Body Thermal Imbalance during Extravehicular Activities

Identification of noninvasive and informative sites on the body reflecting the development of body thermal imbalance during extravehicular activities (EVAs) is highly important for enhancing astronaut safety. Temperature changes were evaluated on several areas of the head (the mastoid fossa (T _mf ), the forehead (T _fo ), and the cheek (T _ch )) and on the fingers (T _fing ). Subjects were dressed in a multicompartment liquid cooling/warming garment. Studies I and II consisted of different combinations of hood versus garment cooling or warming imposed across stages; studies III and IV involved sagittally divided cooling or warming regimes with the hood worn (study III) or with the head uncovered (study IV). In studies I and II, T _mf significantly (P < 0.05) differed between stages 2, when the head was cooled and the rest of the body heated, and 3, when the head was heated and the rest of the body cooled. The T _mf changes were consistent with the thermal conditions imposed on the head but not reflective of the developing body heat deficit. In study III, the T _mf at stages 2 and 3 on the right or the left followed the thermal conditions on the ipsilateral side of the body (P < 0.01). In study IV, T _fing showed no significant differences across stages. In studies I–IV, T _fing showed consistent changes across stages (P < 0.05), reflecting the developing body heat deficit. In all studies, there were no significant differences in rectal temperature (T _re ) across stages. T _mf and temperatures at other head skin sites did not respond in accordance with the actual intensity of a heat or cold flux from the garment and were not reflective of the overall development of body thermal imbalance. T _fing was a more adequate indicator of initial thermal destabilization and provided information that would be useful for monitoring the thermal balance and comfort during EVAs.     

Using hydrothermal time concept to describe sesame (<Emphasis Type="Italic">Sesamum indicum</Emphasis> L.) seed germination response to temperature and water potential

To quantify both temperature (T) and water potential (ψ) effects on sesame (Sesamum indicum L.) seed germination (SG) and also to determine the cardinal T _s for this plant, a laboratory experiment was carried out using hydrothermal time model (HTT). For this purpose, four sesame cultivars (‘Asbomahalleh’, ‘Darab’, ‘Dashtestan’ and ‘Yellowhite’) were germinated at seven constant T _s (20, 25, 30, 35, 37, 39 and 43 °C) at each of the following ψ _s (0, ? 0.12, ? 0.24 and ? 0.36 MPa; provided by PEG 8000). Germination rate (GR) and germination percentage (GP) significantly influenced by ψ, T and their interactions in all cultivars (P ≤ 0.01). There was no significant difference, based on the confidence intervals of the model coefficients, between cultivars, so an average of cardinal T _s was 14.7, 35.4 and 47.2 °C for the minimum (T _b), optimum (T _o) and maximum (T _c) T _s, respectively, in the control condition (0 MPa). Hydrotime values in all cultivars decreased when T was increased to T _o and then remained constant at T _s > T _o (15 MPa h^?1). An average value of ψ _b(50) was estimated to be ? 1.23 MPa at T _s ≤ T _o and then increased linearly (0.1041 MPa°Ch^?1, the slope of the relationship between ψ _b(50) and supra-optimal T _s) with T when T _s increased above T _o and finally reached to zero at T _c. The T _b and T _o values were not influenced by ψ, but T _c value decreased (from 47.2 for zero to 43.5 °C for ? 0.36 MPa) at supra-optimal T _s as a result of the effect of ψ on GR. Based on our findings, this model (as a predictive tool) and or the estimated parameter values in this study can easily be used in sesame SG simulation models to quantitatively characterize the physiological status of sesame seed populations at different T _s and ψ _s.     

Hydrothermal time analysis of watermelon (<Emphasis Type="Italic">Citrullus vulgaris</Emphasis> cv. ‘Crimson sweet’) seed germination

This study evaluated the ability of a hydrothermal time model (HTT) to describe the kinetics of watermelon (Citrullus vulgaris cv. ‘Crimson sweet’) seed germination under different temperatures (T) and water potentials (ψ) and also to determine the cardinal temperatures of watermelon. Results indicated that ψ influenced germination rate and germination percentage. For this seed lot, cardinal temperatures were 10 °C for T _b, 28.34 °C for T _o and 40.8 °C for T _c in the control (0 MPa) treatment. There was a decrease in hydrotime constant (θ _H) when T was increased to T _o and then remained constant at supra-optimal temperatures (30 MPah^?1). Also, at temperatures above T _o, ψ _b(50) values increased linearly with T. The k _T value (the slope of the relationship between ψ _b(50) and T exceeds T _o) of this seed lot was calculated as 0.076 MPa°Ch^?1. Results this study show that when the HTT model is applied, it can accurately describe ψ _b(g) and the course of germination around Ts (R ² = 0.82). Moreover, the ψ _b(50) was estimated to be ?0.96 MPa based on this model. Consequently, the germination response of watermelon for all Ts and ψs can be adequately described by the HTT model and enabling it to be used as a predictive tool in watermelon seed germination simulation models.     

Thermal Preference of the Bush Cricket <Emphasis Type="Italic">Isophya rizeensis</Emphasis>; Testing the Effect of Countergradient Selection

Thermal preference is one of the most crucial components of behavioral thermoregulation in ectotherms, and documenting the adaptation of thermal preference carries great importance for studying the evolution of thermal biology. However there are not many studies focusing on the adaptation of thermal preference in elevational and latitudinal gradients. Isophya rizeensis is a color polymorphic bush cricket species endemic to the mountainous region of northeastern Turkey. Populations of this species are distributed in a wide elevational range between 350 and 2300 m. In this study, we hypothesized that the thermal preference of Isophya rizeensis might follow a countergradient variation where crickets from higher altitudes have higher temperature preferences compared to crickets from lower altitudes. To test this hypothesis, thermal preference values (T _pref ) of crickets from three altitudes groups (low, middle and high) were measured with a thermal gradient experiment. Additionally, body temperatures (T _b ) and environmental temperatures (T _a ) were measured in field. Deviation values of T _b and T _a from T _pref were calculated to investigate the extent of thermoregulation. As Isophya rizeensis is color polymorphic species where morphology pattern changes from lighter to darker types with increasing altitude we also tested whether coloration has any effect on temperature excess (T _ex ) and thermoregulation. Thermal preference values did not differ significantly between three groups and also colouration does not influence the extent of thermoregulation in this species. These results indicate that there is not sufficient evidence for the existence of a countergradient selection related with thermal behavior. However, the deviation of body (D _b ) and environmental (D _a ) temperatures suggest that at higher altitudes thermoregulation might be more efficient than lower altitudes.     

Nonquasineutral relativistic current filaments and their X-ray emission

Nonquasineutral electron current filaments with the azimuthal magnetic field are considered that arise due to the generation of electron vorticity in the initial (dissipative) stage of evolution of a current-carrying plasma, when the Hall number is small (σB/en _e c ? 1) because of the low values of the plasma conductivity and magnetic field strength. Equilibrium filamentary structures with both zero and nonzero net currents are considered. Structures with a zero net current type form on time scales of t < t _sk = (r ₀ω _pe /c)² t _st, where t _sk is the skin time, t _st is the typical time of electron-ion collisions, and r ₀ is the radius of the filament. It is shown that, in nonquasineutral filaments in which the current is carried by electrons drifting in the crossed electric (E _r ) and magnetic (B _θ) fields, ultrarelativistic electron beams on the typical charge-separation scale r _B = B/(4πen _e ) (the so-called magnetic Debye radius) can be generated. It is found that, for comparable electron currents, the characteristic electron energy in filaments with a nonzero net current is significantly lower than that in zero-net-current filaments that form on typical time scales of t < t _sk. This is because, in the latter type of filaments, the oppositely directed electron currents repel one another; as a result, both the density and velocity of electrons increase near the filament axis, where the velocities of relativistic electrons are maximum. Filaments with a zero net current can emit X rays with photon energies ? ω up to 10 MeV. The electron velocity distributions in filaments, the X-ray emission spectra, and the total X-ray yield per unit filament length are calculated as functions of the current and the electron number density in the filament. Analytical estimates of the characteristic lifetime of a radiating filament and the typical size of the radiating region as functions of the plasma density are obtained. The results of calculations are compared with the available experimental data.     

Effect of the anode material on the X-ray spectrum of micropinch discharge plasma

The effect of the elemental composition of the anode material on the parameters and X-ray spectrum of micropinch discharge plasma have been studied using a low-inductance vacuum spark device. It is shown that the plasma electron temperature T _e and intensity of hard X-ray emission increase with increasing nuclear charge number Z of the anode material of the discharge system.     

A novel NADPH-dependent reductase of <Emphasis Type="Italic">Sulfobacillus acidophilus</Emphasis> TPY phenol hydroxylase: expression,characterization, and functional analysis

The reductase component (MhpP) of the Sulfobacillus acidophilus TPY multicomponent phenol hydroxylase exhibits only 40 % similarity to Pseudomonas sp. strain CF600 phenol hydroxylase reductase. Amino acid sequence alignment analysis revealed that four cysteine residues (Cys-X ₄ -Cys-X ₂ -Cys-X _29-35 -Cys) are conserved in the N terminus of MhpP for [2Fe-2S] cluster binding, and two other motifs (RXYS and GXXS/T) are conserved in the C terminus for binding the isoalloxazine and phosphate groups of flavin adenine dinucleotide (FAD). Two motifs (S/T-R and yXCGp) responsible for binding to reduce nicotinamide adenine dinucleotide phosphate (NADPH) are also conserved in MhpP, although some residues differ. To confirm the function of this reductase, MhpP was heterologously expressed in Escherichia coli BL21(DE3) and purified. UV-visible spectroscopy and electron paramagnetic resonance spectroscopy revealed that MhpP contains a [2Fe-2S] cluster. MhpP mutants in which the four cysteine residues were substituted via site-directed mutagenesis lost the ability to bind the [2Fe-2S] cluster, resulting in a decrease in enzyme-specific oxidation of NADPH. Thin-layer chromatography revealed that MhpP contains FAD. Substrate specificity analyses confirmed that MhpP uses NADPH rather than NADH as an electron donor. MhpP oxidizes NADPH using cytochrome c, potassium ferricyanide, or nitro blue tetrazolium as an electron acceptor, with a specific activity of 1.7 ± 0.36, 0.78 ± 0.13, and 0.16 ± 0.06 U/mg, respectively. Thus, S. acidophilus TPY MhpP is a novel NADPH-dependent reductase component of phenol hydroxylase that utilizes FAD and a [2Fe-2S] cluster as cofactors.     

Analysis of the dependence of surfatron acceleration of electrons by an electromagnetic wave in space plasma on the particle momentum along the wave front

Based on the numerical solution of the nonlinear nonstationary second-order equation for the wave phase on the particle trajectory, the dynamics of surfatron acceleration of electrons by an electromagnetic wave propagating across the external magnetic field in space plasma is analyzed as a function of the electron momentum along the wave front. Numerical calculations show that, for strongly relativistic initial values of the electron momentum component along the wave front g _y (0) (the other parameters of the problem being the same), electrons are trapped into the regime of ultrarelativistic surfatron acceleration within a certain interval of the initial wave phase Ψ(0) on the particle trajectory. It is assumed in the calculations that |Ψ(0)| ≤ π. For strongly relativistic values of g _y (0), electrons are immediately trapped by the wave for 19% of the initial values of the phase Ψ(0) (favorable phases). For the rest of the values of Ψ(0), trapping does not occur even at long times. This circumstance substantially simplifies estimations of the wave damping due to particle acceleration in subsequent calculations. The dynamics of the relativistic factor and the components of the electron velocity and momentum under surfatron acceleration is also analyzed. The obtained results are of interest for the development of modern concepts of possible mechanisms of generation of ultrarelativistic particle fluxes in relatively calm space plasma, as well as for correct interpretation of observational data on the fluxes of such particles and explanation of possible reasons for the deviation of ultrarelativistic particle spectra detected in the heliosphere from the standard power-law scalings and the relation of these variations to space weather and large-scale atmospheric processes similar to tropical cyclones.     

Prediction of Successful Personal Cognitive Performance Based on Integrated Characteristics of Multichannel EEG

The present study aimed to assess the possible relationship between psychometric and electroencephalographic (EEG) parameters in humans. Normalized parameters of the integrated spatial (p _S ) and integrated temporal (p _T ) regularities of real resting EEG with the eyes closed were calculated. The algorithm of estimation of these parameters was based on the calculation of empirical multivariate temporal structure function of the first order. It was revealed that p _S and p _T parameters varied in a specific range, which was characterized by well-defined individual configuration reflecting the variability type (spatial, temporal, or mixed) of resting EEG. Obtained p _S and p _T parameters were compared to the speed of performed cognitive activity. The cognitive tasks included nonverbal subtests of the Wechsler Adult Intelligence Scale (WAIS) including block design according to a given template and construction of an object without any template, and motor probe. The successful performance on cognitive tasks was detected to be achieved with different combinations of p _S and p _T parameters in different subjects. Thus, the same intelligence resource can probably be organized with nonlinear principle in different subjects.     

<Emphasis Type="Italic">Nibribacter flagellatus</Emphasis> sp. nov., isolated from rhizosphere of <Emphasis Type="Italic">Hibiscus syriacus</Emphasis> and emended description of the genus <Emphasis Type="Italic">Nibribacter</Emphasis>

A Gram-stain negative, aerobic, motile by flagella, rod-shaped strain (THG-T16^T) was isolated from rhizosphere of Hibiscus syriacus. Growth occurred at 10–40 °C (optimum 28–30 °C), at pH 6.0–8.0 (optimum 7.0) and at 0–1.0% NaCl (optimum 0%). Based on 16S rRNA gene sequence analysis, the near phylogenetic neighbours of strain THG-T16^T were identified as Nibribacter koreensis KACC 16450^T (98.6%), Rufibacter roseus KCTC 42217^T (94.7%), Rufibacter immobilis CCTCC AB 2013351^T (94.5%) and Rufibacter tibetensis CCTCC AB 208084^T (94.4%). The DNA G+C content of strain THG-T16^T was determined to be 46.7 mol%. DNA–DNA hybridization values between strain THG-T16^T and N. koreensis KACC 16450^T, R. roseus KCTC 42217^T, R. immobilis CCTCC AB 2013351^T, R.tibetensis CCTCC AB 208084^T were 33.5?±?0.5% (31.7?±?0.7% reciprocal analysis), 28.1?±?0.2% (25.2?±?0.2%), 17.1?±?0.9% (10.2?±?0.6%) and 8.1?±?0.3% (5.2?±?0.1%). The polar lipids were identified as phosphatidylethanolamine, two unidentified aminophospholipids, an unidentified aminolipid and three unidentified lipids. The quinone was identified as MK-7 and the polyamine as sym-homospermidine. The major fatty acids were identified as C_16:1 ω5c, C_17:1 ω6c, iso-C_15:0, summed feature 3 (C_16:1 ω7c and/or C_16:1 ω6c) and summed feature 4 (iso-C_17:1 I and/or anteiso-C_17:1 B). On the basis of the phylogenetic analysis, chemotaxonomic data, physiological characteristics, and DNA–DNA hybridization data, strain THG-T16^T represents a novel species of the genus Nibribacter, for which the name Nibribacter flagellatus sp. nov. is proposed. The type strain is THG-T16^T(=?KACC 19188^T?=?CCTCC AB 2016246^T).     

<Emphasis Type="Italic">Halomonas tibetensis</Emphasis> sp. nov., isolated from saline lakes on Tibetan Plateau

Strains pyc13^T and ZGT13 were isolated from Lake Pengyan and Lake Zigetang on Tibetan Plateau, respectively. Both strains were Gram-negative, catalase- and oxidase-positive, aerobic, rod-shaped, nonmotile, and nonflagellated bacteria. Phylogenetic analysis based on 16S rRNA gene sequences showed that strains pyc13^T and ZGT13 belong to the genus Halomonas, with Halomonas alkalicola 56-L4-10aEn^T as their closest neighbor, showing 97.4% 16S rRNA gene sequence similarity. The predominant respiratory quinone of both strains was Q-9, with Q-8 as a minor component. The major fatty acids of both strains were C_18:1ω6c/C_18:1ω7c, C_16:1ω6c/C_16:1ω7c, C_16:0, and C_12:0 3OH. The polar lipids of both strains consisted of phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, glycolipid, phospholipids of unknown structure containing glucosamine, and unidentified phospholipids. The DNA G + C content of pyc13^T and ZGT13 were 62.6 and 63.4 mol%, respectively. The DNA-DNA hybridization values of strain pyc13^T were 34, 41, 61, 35, and 35% with the reference strains H. alkalicola 56-L4-10aEn^T, H. sediminicola CPS11^T, H. mongoliensis Z-7009^T, H. ventosae Al12^T, and H. fontilapidosi 5CR^T, respectively. Phenotypic, biochemical, genotypic, and DNA-DNA hybridization data showed that strains pyc13^T and ZGT13 represent a new species within the genus Halomonas, for which the name H. tibetensis sp. nov. is proposed. The type strain is pyc13^T (= CGMCC 1.15949^T = KCTC 52660^T).     

Nonlinear dynamics of beam–plasma instability in a finite magnetic field

The nonlinear dynamics of beam–plasma instability in a finite magnetic field is investigated numerically. In particular, it is shown that decay instability can develop. Special attention is paid to the influence of the beam?plasma coupling factor on the spectral characteristics of a plasma relativistic microwave accelerator (PRMA) at different values of the magnetic field. It is shown that two qualitatively different physical regimes take place at two values of the external magnetic field: B ₀ = 4.5 kG (Ω ~ ωB _p ) and 20 kG (Ω _B ? ω_p). For B ₀ = 4.5 kG, close to the actual experimental value, there exists an optimal value of the gap length between the relativistic electron beam and the plasma (and, accordingly, an optimal value of the coupling factor) at which the PRMA output power increases appreciably, while the noise level decreases.     

Temperature sensitivity of soil respiration in a low-latitude forest ecosystem varies by season and habitat but is unaffected by experimental warming

Experimental warming of forest ecosystems typically stimulates soil respiration (CO₂ efflux), but most warming experiments have been conducted in northern latitudes (>?40°N) with relatively young soils. We quantified the influence of experimental warming on soil respiration (R_T) in two adjacent forest habitats—a mature, closed canopy forest and a gap where trees were manually removed— on highly-weathered Ultisols of the southeastern U.S. (33°N). Using temperature variation, both natural and induced by experimental warming, we also quantified the temperature sensitivity of R_T, defined as the activation energy, E_A in the Arrhenius equation. Experimental warming (either + 3 °C or + 5 °C above ambient) did not significantly increase soil respiration rate or cumulative CO₂ loss over the 3 years of the experiment, and did not influence the temperature sensitivity of soil respiration, once the influence of natural temperature variation was taken into consideration. Despite the absence of an experimental warming effect, we observed that E_A varied on monthly time scales, and varied differently in each habitat. Soil moisture and habitat also influenced R_T, but the effects were not consistent, and varied by month. Our results suggest that although R_T does depend on temperature, the sensitivity of R_T to temperature variation is influenced primarily by factors like microclimate and plant phenology that can change on relatively short (<?monthly) time scales. Thus, using the temperature sensitivity of R_T to predict future CO₂ losses due to warming is only reasonable if monthly variation in E_A is incorporated into models for lower-latitude subtropical ecosystems with highly weathered soils, such as those in this study. Finally, our results suggest that higher temperatures may not enhance R_T in highly-weathered, C-poor soils to the extent that has been reported in prior studies of high-latitude soils, which may constrain ecosystem-atmosphere carbon exchanges and feedbacks to the climate system.     

Suspended-sediment responses after strip thinning in headwater catchments

We examined changes in suspended-sediment yields (SSY) after a 50 % strip thinning in headwater streams draining a Japanese cedar (Cryptomeria japonica) and cypress (Chamaecyparis obtusa) plantation forest. We applied a paired-catchment analysis to treated (K _T : 17.1 ha) and control (K _C : 8.9 ha) catchments. Annual suspended-sediment yield (SSY_an) in the prethinning period in the K _T and K _C catchments was 110.0 and 142.1 kg/ha per year. For the postthinning period, SSY_an in the K _T catchment became 5055.6 kg/ha per year, whereas that in the K _C catchment increased 893.2 kg/ha per year. The paired-catchment analysis revealed that SSY in the K _T catchment increased 17.0-fold compared with the prethinning period. However, the dominant hysteresis pattern remained clockwise in both pre- and postthinning periods. Sequences of large storm events in the postthinning period elevated SSY in both catchments. Increase in suspended sediment in the K _T catchment was associated with the combined impacts of thinning and sequences of storm events during the period of thinning operation.     

<Emphasis Type="Italic">Phenylobacterium terrae</Emphasis> sp. nov., isolated from a soil sample of Khyber-Pakhtun-Khwa,Pakistan

A Gram-stain negative, aerobic, motile, non-spore-forming and rod-shaped bacterial strain, designated YIM 730227^T, was isolated from a soil sample, collected from Karak district, Khyber-Pakhtun-Khwa, Pakistan. The bacterium was characterized using a polyphasic taxonomic approach. Pairwise comparison of the 16S rRNA gene sequences showed that strain YIM 730227^T is closely related to Phenylobacterium lituiforme FaiI3^T (97.5% sequence similarity), Phenylobacterium muchangponense A8^T (97.4%), Phenylobacterium panacis DCY109^T (97.1%), Phenylobacterium immobile E^T (97.1%) and Phenylobacterium composti 4T-6^T (97.0%), while also sharing 98.0% sequence similarity with Phenylobacterium hankyongense HKS-05^T after NCBI blast, showing it represents a member of the family Caulobacteraceae. The major respiratory quinone was Q-10 and the major fatty acids were C_16:0, summed feature 8 (comprising C_18:1ω7c and/or C_18:1ω6c), C_18:1ω7c 11-methyl and C_17:0. The polar lipids were phosphatidylglycerol, unidentified glycolipids, phospholipid and unidentified lipid. The G?+?C content of the genomic DNA was 68.2 mol%. The DNA–DNA relatedness values of strain YIM 730227^T with P. hankyongense HKS-05^T, P. lituiforme FaiI3^T, P. muchangponense A8^T, P. panacis DCY109^T, P. immobile E^T and P. composti 4T-6^T were 31.3?±?0.6, 26.1?±?0.2, 24.3?±?0.1, 21.8?±?0.9, 19.8?±?0.6 and 18.2?±?1.1%, respectively, values lower than 70%. Besides the morphological and chemotaxonomic characteristics, phylogenetic analyses of 16S rRNA gene sequences and the biochemical characteristics indicated that the strain YIM 730227^T represents a novel member of the genus Phenylobacterium, for which the name Phenylobacterium terrae sp. nov. (type strain YIM 730227^T =?KCTC62324^T?=?CGMCC 1.16326^T) is proposed.     

Plasma diagnostics from intensities of resonance line series of He-like ions

The possibility of using the relative intensities of the 1snp ¹P₁–1s ^{2 1}S0 transitions with n = 3–6 in He-like multicharged ions to diagnose plasma in a nonstationary ionization state is considered. The calculations performed for F VIII ions show that, at electron temperatures of T _e = 10–100 eV, the intensity ratios are sensitive to the plasma electron density in the range of N _e = 10¹⁶–10²⁰ cm^–3. The universal calculated dependences can be used to diagnose various kinds of recombining or ionizing plasmas containing such ions.     

<Emphasis Type="Italic">Limnobacter humi</Emphasis> sp. nov., a thiosulfate-oxidizing,heterotrophic bacterium isolated from humus soil,and emended description of the genus <Emphasis Type="Italic">Limnobacter</Emphasis> Spring <Emphasis Type="Italic">et al.</Emphasis> 2001

Three Gram-negative, strictly aerobic, chemolithoheterotrophic bacterial strains, designated UCM-30, UCM-33, and UCM-39^T, were isolated in South Korea. Based on their 16S rRNA gene sequences, the three isolated strains were found to be similar to Limnobacter thiooxidans CS-K2^T (97.41–97.68%), Limnobacter litoralis KP1-19^T (95.55–95.76%), and various genera belonging to the class Betaproteobacteria (90.34–93.34%). DNA-DNA hybridization showed 79.3–83.9% similarity between the genomic DNA of UCM-39^T, UCM-30, and UCM-33, while the sequence similarity between UCM-39^T and L. thiooxidans KACC 13837T or L. litoralis LMG 24869T was 23.7% and 18.6%, respectively. The DNA G+C content of UCM 39T was 59.7 mol%, the major ubiquinone was Q-8, and the optimal oxidation rate was observed at 10 mM thiosulfate. The major fatty acids (≥ 10%) were summed features 3 (C_16:1 ω7c and/or C_16:1 ω6c) and 8 (C_18:1 ω7c and/or C_18:1 ω6c), and C_16:0. The major polar lipids (diphosphatidylglycerol, phosphatidylethanolamine, and phosphatidylglycerol) were found in all members of genus Limnobacter. Based on phenotypic, physiological, and phylogenetic analyses, the UCM-39T strain was found to be significantly distinct to represent a novel species affiliated to the genus Limnobacter. We propose to name it Limnobacter humi sp. nov. with the type strain UCM-39^T (=KACC 18574^T =NBRC 111650^T).