Physical parameters for the Saturn atmosphere computed by using voyager data

We have computed the following physical parameters for the atmosphere of Saturn: 1) Temperature, 2) Pressure, 3) Density, 4) Density Scale, 5) Number Density, 6) Viscosity, 7) Mean Pressure Scale, 8) Mean Particle Velocity, 9) Mean Collisional Frequency, 10) Columnar Mass, and 11)Mean Free Path. Voyager 2 measurements have been used in order to compute the above parameters from 0 to 300 km above the top of the clouds. From 0 to 300 km below the top of the clouds, ground based measurements have been used.     

Outstanding issues in understanding the dynamics of the inner plasma sheet and ring current during storms and substorms

The paper deals with five selected issues of the dynamical coupling of the near-Earth plasma sheet and magnetosphere, (1) substorm initiation, (2) dipolarization, (3) pressure release of the outer magnetosphere via the auroral energy conversion process, (4) magnetization of the very high beta plasma assembling at the inner edge of the tail, and (5) penetration of energetic particles into the ring current below L 4. One outstanding and strongly debated subject is not discussed here, the origin of the substorm current wedge. The main conclusions (or personal preferences) are: (1) the substorm is initiated by formation of a near-Earth neutral line; (2) dipolarization occurs through magnetic flux transport by the earthward reconnection flow and not by current diffusion; (3) the auroral energy conversion process, the “auroral pressure valve”, contributes substantially to the pressure release during the substorms; (4) high beta ( 10) plasma breaks up into smaller scale blobs under slow magnetization; and (5) deep and prolonged penetration of hot plasma sheet plasma into the middle magnetosphere produces currents and electric fields which lead to the growth of the storm-time ring current.     

Selection of sensors and spectral bands of marine observation satellite (MOS) — 1

After trading off the proposed requirements by the Committee on Earth Observation Satellite Development, cost and time for development of sensors, spacecraft and launch vehicle, the following sensors were selected for Marine Observation Satellite (MOS) - 1.(1) Four channel visible and near IR sensor (MESSR) with 50 meter resolution. (2) Four channel visible and thermal IR sensor (VTIR) with 0.9 km (visible) and 2.7 km (IR) resolution respectively. Out of three IR channels, two channels are atmospheric window channels while the third channel is water vapor absorption band. (3) Two channel microwave scanning radiometer (MSR) with responsivity in 23.8 and 31.4 GHz respectively. (4) Data collection system.     

银河宇宙线在电离层D层中电离的全球分布

本文从带电粒子对D层大气电离出发, 给出了宇宙线相对论粒子、非相对论粒子及低能粒子在地球大气中的电离公式, 从而给出了宇宙线在电离层D层中电子产生率q(h)和电子密度N(h)的全球分布.结果表明, 宇宙线产生的q(h)和N(h)具有明显的纬度效应, 在极区产生的q(h)和N(h)要比低纬高得多, 当截止刚度R_c=10—18GV时, q(h)的变化相差很小.太阳活动11年调制对q(h)的影响是明显的, 但远小于R_c对q(h)的影响.大气密度ρ(h)对q(h)的影响主要是随高度的变化.      

Mars ultraviolet imaging spectrometer experiment on the PLANET-B mission

An ultraviolet imaging spectrometer (UVS) has been developed for the PLANET-B spacecraft. The UVS instrument is composed of a grating spectrometer (UVS-G) and a D/H absorption cell photometer (UVS-P). The UVS-G is a flat-field type spectrometer measuring optical emissions in the FUV and MUV range between 115 nm and 310 nm with a spectral resolution of 2 – 3 nm. The UVS-P is a photometer detecting hydrogen (H) and deuterium (D) Lyman α emissions separately by an absorption cell technique. Scientific targets of the UVS experiment are the investigation of (1) hydrogen and oxygen coronas around Mars, (2) the D/H ratio in the upper atmosphere, (3) dayglow, (4) aurora and nightglow, (5) dust, clouds and ozone, and (6) the surface composition of Phobos and Deimos.     

A quantitative assay of biologically important compounds in simulated primitive Earth experiments.

A CH4-N2-H2OV gas mixture was subjected to a high voltage (20 kV), high frequency (0.3 MHz) electric discharge. The energy input in the electric discharge was varied from 0.016 to 3.048 MJ mol-1. The chemical yields (G), expressed as the number of molecules formed or destroyed per 100 eV of energy input were calculated for several products. The G values calculated at the lowest energy input were (-CH4) = 6.48; (-N2) = 2.51; (C2H2) = 1.16; (HCN) = 0.215; (CH3CHO) = 0.115; (CH3CH2CHO) = 0.00161; (CH3(CH2)2CHO) = 0.0165; ((CH2CO2H)2) = 0.0000339; (CH4 --> Solid material) = 0.196; (N2 --> Solid material) = 0.00355. This is the first report in prebiotic studies in which the G values of various products in electric discharge experiments are determined. This type of study is needed in order to get a better insight into the relative role of electric discharges on the primitive Earth.     

Active galaxies observed by IUE

IUE has extended the grasp of ultraviolet astronomy to cover active galaxies and quasars fainter than the sixteenth magnitude. These observations have:(i) provided a diagnostic for the source of ionization in active galaxies,(ii) cast light on the excitation mechanism of the Fe II lines,(iii) shown the broad hydrogen lines in Seyferts and quasars are not in their recombination ratios,(iv) demonstrated the absence of gas in BL Lac objects,(v) supported the gravitational lens explanation of the double quasar,(vi) demonstrated the presence of a hot (30 000 K) black body in active nuclei,(vii) discovered stratification of the ionization conditions in the Broad Line Regions of active nuclei.     

Modeling M(3000)F2 based on extreme learning machine

This paper presents an novel extreme learning machine (ELM)-based prediction model for the ionospheric propagation factor M(3000)F2 at Darwin station (12.4°S, 131.5°E; −44.5°dip) in Australia. The proposed ELM model is trained with hourly daily values of M(3000)F2 from the period 1998–2014 except 2001 and 2009. The hourly daily values of 2001 (high solar activity) and 2009 (low solar activity) are used for validating the prediction accuracy. The proposed ELM for modeling M(3000)F2 can achieve faster training process and similar testing accuracy compared with backward propagation neural network (BPNN). In addition, the performance of the ELM is verified by comparing the predicted values of M(3000)F2 with observed values and the international reference ionosphere (IRI −2016) model predicted values. Based on the error differences (the root mean square error (RMSE) and the M(3000)F2 percentage improvement values M(3000)F2_IMP(%)), the result demonstrates the effectiveness of the ELM model compared with the IRI-2016 model at hourly, daily, monthly, and yearly in high (2001) and low (2009) solar activity years. The ELM also shows good agreement with observations compared with the IRI during disturbed magnetic activity.     

Determination of the threshold acceleration for the gravitropic stimulation of cress roots and hypocotyls.

To determine the range of the threshold acceleration (a-threshold) for the gravitropic stimulation of Lepidium sativum L. roots and hypocotyls, experiments were performed on a centrifuge-clinostat with two-orthogonal axes. The rotation rate of the clinostat was 4 rpm (< or = 1.8 x 10(-4) g), while that of the centrifuge was from 3 to 17 rpm (3 x 10(-3) to 10(-1) g). The gravitropic response was determined: (i) after growth of roots and hypocotyls in their normal vertical position and subsequent gravitropic stimulation for 3 h by accelerations of 4 x 10(-3) to 10(-1) g, and (ii) after continuous stimulation in the lateral direction by centripetal accelerations of 4 x 10(-3) to 10(-1) g. The a-threshold was defined by an extrapolation of the regression line of R = p + rx, where x was either ln a or l/a for 3 h or a continuous stimulation, respectively. The a-threshold estimated after 3 h stimulation was equal to 2.6 x 10(-3) g for roots and 3.1 x 10(-3) g for hypocotyls. The threshold accelerations that were unable to evoke a gravitropic response even with continuous stimulation of cress roots and hypocotyls were approximately 3.1 x 10(-3) g and 3.6 x 10(-3) g, respectively. Increasing the stimulation acceleration up to 4.1 x 10(-3) g led to a statistically confirmed gravitropic response of a definite proportion of both the root and hypocotyl populations. In the experiments where acceleration and stimulation time were variable, the threshold dose (D-threshold) for roots was determined to be about 14 to 22 g x s, depending on the stimulation duration and the range of accelerations. The kinetics of gravitropic response at a near-threshold acceleration (4 x 10(-3) to 1.9 x 10(-2) g) differed from that at 1 g (horizontal stimulation). At low forces, the maximal response dependent on the magnitude of acceleration could not be enhanced by increasing the stimulation time up to at least 210 min.     

Effect of condensation agents and minerals for oligopeptide formation under mild and hydrothermal conditions in related to chemical evolution of proteins

The role of condensation agents and minerals for oligopeptide formation was inspected to see whether minerals possess catalytic activity under mild and hydrothermal conditions. Under mild conditions, oligopeptide formation from negatively charged amino acids (Asp and Glu) using different minerals and the elongation of alanine oligopeptides ((Ala)₂–(Ala)₅) were attempted using apatite minerals. Oligo(Asp) up to 10 amino acid units from Asp were observed in the presence of 1-ethyl-3-(3-dimethylaminopropyl carbodiimide (EDC). Notable influence of minerals was not detected for the oligo(Asp) formation. Oligo(Asp) was gradually degraded by the further incubation in the presence of EDC in both the absence and presence of minerals. The formation of oligo(Glu) was less efficient in the presence of carbonyldiimidazole. The elongation from (Ala)₃, (Ala)₄, and (Ala)₅ and the formation of diketopiperazine from (Ala)₂ proceeded immediately in the presence of EDC in the meantime of the sample preparations. In addition, it was unexpected that the disappearance of the products and the reformation of the reactants occurred by the further incubation for 24 h; for instance, (Ala)₅ decreased but (Ala)₄ increased with increasing the reaction time in the reaction of (Ala)₄ with EDC. These facts suggest that the activation of the reactant amino acids or peptides immediately occurs. Under the simulated hydrothermal conditions, EDC did not enhance the formation of oligopeptides from Asp, Glu or Ala nor the spontaneous formation of (Ala)₅ from (Ala)₄.     

Equatorial M(3000)F2 estimation of F2-layer models peak heights during low solar activity

M(3000)F2 estimation of h_mF2 based on four different formulated models viz: (1) Shimazaki (1955) (2) Bradley and Dudeney (1973), (3) Dudeney (1974) and (4) Bilitza et al. (1979) at an equatorial station in West Africa during low solar activity period (1995) are used to validate its conformity with observed and International Reference Ionosphere (IRI) model. Local time analyses of data from fifteen (15) selected days during the January and July solstices and April and October equinoxes are used. The results obtained show that the M(3000)F2 estimation of h_mF2 from the ionosonde-measured values using the Ionospheric Prediction Service (IPS-42) sounder compared to the observed values which were deduced using an algorithm from scaled virtual heights of quiet day ionograms are highly correlated with Bilitza model. International Reference Ionosphere (IRI 2007) model for the equatorial region also agrees with the formulation developed by Bilitza et al. (1979) for the four different seasons of the year. h_mF2 is highest (425 km) in summer (June solstice) season and lowest (386 km) in autumn (September equinox) season with daytimes peaks occurring at 1100–1200 LT during the solstices and at 1000 LT during the equinoxes respectively. Also, the post-sunset peaks are highest (362 km) at the spring (March equinox) and lowest (308 km) at the summer (June solstice) both occurring between 1800 and 2000 LT.     

A new global version of M(3000)F2 prediction model based on artificial neural networks

A new version of global empirical model for the ionospheric propagation factor, M(3000)F2 prediction is presented. Artificial neural network (ANN) technique was employed by considering the relevant geophysical input parameters which are known to influence the M(3000)F2 parameter. This new version is an update to the previous neural network based M(3000)F2 global model developed by Oyeyemi et al. (2007), and aims to address the inadequacy of the International Reference Ionosphere (IRI) M(3000)F2 model (the International Radio Consultative Committee (CCIR) M(3000)F2 model). The M(3000)F2 has been found to be relatively inaccurate in representing the diurnal structure of the low latitude region and the equatorial ionosphere. In particular, the existing hmF2 IRI model is unable to reproduce the sharp post-sunset drop in M(3000)F2 values, which correspond to a sharp post-sunset peak in the peak height of the F2 layer, hmF2. Data from 80 ionospheric stations globally, including a good number of stations in the low latitude region were considered for this work. M(3000)F2 hourly values from 1987 to 2008, spanning all periods of low and high solar activity were used for model development and verification process. The ability of the new model to predict the M(3000)F2 parameter especially in the low latitude and equatorial regions, which is known to be problematic for the existing IRI model is demonstrated.     

太阳风-磁层-电离层耦合过程中的能量收支

太阳风向磁层电离层(Magnetosphere and Ionosphere, MI)系统输入能量, 而输入的能量随后在MI系统中消耗. 本文从能量守恒原理出发, 讨论太阳风-磁层-电离层 (SMI)耦合过程中的能流路径和能量收支的定量关系. 主要讨论9个问题: (1) 太阳风向MI系统的能量输入, (2) MI系统对能量输入的响应, (3) 环电流的能量消耗, (4) 极区电离层焦耳加热的能量消耗, (5) 极光粒子沉降的能量消耗, (6) 磁尾能量的消耗、储存以及返回下游太阳风, (7)平静期间的能量积累与释放, (8)能量在不同能汇中的分配, (9)评价能量函数的准则和方法.      

Assessing ecohydrological factors variations and their relationships at different spatio-temporal scales in semiarid area,northwestern China

As a typical semiarid farming-pastoral ecotone sensitive to the environmennt, the Plain of West Liaohe Basin (WLBP) is currently experiencing drastic environmental changes. To identify how environmental change affect vegetation in the WLBP, we analysed spatiotemporal variation characteristics of Ecological environment factors based on monthly and annual air temperature (T), precipitation (P) and Normalized Difference Vegetation Index (NDVI) from 1982 to 2015. And the correlations between them were investigated by correlation analysis (Simple correlation, partial correlation and complex correlation) at temporal and spatial scale. The results showed that: (1) the vegetation growth of the WLBP showed ameliorated trend, with a change rate of 0.004/yr.; (2) P was more sensitive to NDVI than T; (3) and the influence of hydrothermal changes on vegetation growth was more significant than that of the change of single climate factors at time scales; (4) the effects of anthropogenic factors on vegetation change were 75.07% (1982–1993) and 98.08% (1994–2015), respectively. At the temp-special scales, P&T and land use type change (LUCC) were the main climatic and anthropogenic factors that affect vegetation changes, respectively.     

An improved approach to model regional ionosphere and accelerate convergence for precise point positioning

Given the severe effects of the ionosphere on global navigation satellite system (GNSS) signals, single-frequency (SF) precise point positioning (PPP) users can only achieve decimeter-level positioning results. Ionosphere-free combinations can eliminate the majority of ionospheric delay, but increase observation noise and slow down dual-frequency (DF) PPP convergence. In this paper, we develop a regional ionosphere modeling and rapid convergence approach to improve SF PPP (SFPPP) accuracy and accelerate DF PPP (DFPPP) convergence speed. Instead of area model, ionospheric delay is modeled for each satellite to be used as a priori correction. With the ionospheric, wide-lane uncalibrated phase delay (UPD) and residuals satellite DCBs product, the wide-lane observations for DF users change to be high-precision pseudorange observations. The validation of a continuously operating reference station (CORS) network was analyzed. The experimental results confirm that the approach considerably improves the accuracy of SFPPP. For DF users, convergence time is substantially reduced.     

The CELSS Test Facility project: an example of a CELSS flight experiment system.

The CELSS Test Facility (CTF) is a device for measuring crop plant productivity in the micro-gravity environment of Space Station Freedom. It will allow us to address questions of crop productivity in space, versus that on the ground. The crop productivity factors that will be measured are rates of: 1) biomass production, 2) food production, 3) O2 and CO2 exchange, and 4) water transpiration. In addition, other productivity factors of specific crops will be determined, such as : 1) the ratio of edible to inedible biomass (harvest index), 2) leaf area exposed to and collecting light (leaf area index), 3) ratio of root mass to total biomass, and 4) photosynthetic efficiency (ratio of moles of CO2 fixed (or O2 produced), per mole of photons of specific energies used). Plant and crop morphology, at several levels, ranging from the community to the sub-cellular, will also be evaluated.     

Evaluation of Voigt algorithms for the ISS/JEM/SMILES L2 data processing system

We present a calculation of the accuracy and speed of the Voigt function of various algorithms (Armstrong (1967), Hui et al. (1978), Humlicek (1982) and improved version of Kuntz (1997) developed in this study) for making the faster and higher accuracy forward model required for the Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES) Level 2 (L2) data processing system.     

High spectral resolution line profiles and images of comet Halley

High-spectral-resolution line profiles and images of comet Halley were obtained in 1986 at the National Solar Observatory McMath telescope, using a dual-etalon Fabry-Perot spectrometer. The spectrometer was designed to obtain data in four distinct modes: (1) high-resolution (R = 200,000) scanning, (2) high-resolution imaging, (3) moderate resolution (R = 30,000) scanning, and (4) moderate resolution imaging. This paper describes the instrument and some examples of data obtained in the high-resolution scanning mode.     

Features of vestibuloocular reflex modulations induced by altered gravitational forces in tadpoles (Xenopus laevis).

In Xenopus laevis tadpoles, we studied the static vestibuloocular reflex (rVOR) in relation to modifications of the gravitational environment to find basic mechanisms of how altered gravitational forces (AGF) affect this reflex. Animals were exposed to microgravity during space flight or hypergravity (3g) for 4 to 12 days. Basic observations were that (1)the development of the rVOR is significantly affected by altered gravitational conditions, (2) the duration of 1g-readaptation depends on the strength of the test stimulus, (3) microgravity induces malformations of the body which are related to the rVOR depression. Future studies are based on the hypotheses (1) that the vestibular nuclei play a key roll in the adaptation to AGF conditions, (2) that the stimulus transducing systems in the sense organ are affected by AGF conditions, and (3) that fertilized eggs will be converted to normal adults guided by physiological and morphological set points representing the genetic programs. Developmental retardation or acceleration, or otherwise occurring deviations from standard development during embryonic and postembryonic life will activate genes that direct the developmental processes towards normality.     

A comparative study of ionospheric IRIEup and ISP assimilative models during some intense and severe geomagnetic storms

Three-dimensional (3-D) electron density matrices, computed in the Mediterranean area by the IRI climatological model and IRIEup and ISP nowcasting models, during some intense and severe geomagnetic-ionospheric storms, were ingested by the ray tracing software tool IONORT, to synthesize quasi-vertical ionograms. IRIEup model was run in different operational modes: (1) assimilating validated autoscaled electron density profiles only from a limited area which, in our case, is the Mediterranean sector (IRIEup_re(V) mode); (2) assimilating electron density profiles from a larger region including several stations spread across Europe: (a) without taking care of validating the autoscaled data in the assimilation process (IRIEup(NV)); (b) validating carefully the autoscaled electron density profiles before their assimilation (IRIEup(V)).The comparative analysis was carried out comparing IRI, IRIEup_re(V), ISP, IRIEup(NV), and IRIEup(V) foF2 synthesized values, with corresponding foF2 measurements autoscaled by ARTIST, and then validated, at the truth sites of Roquetes (40.80°N, 0.50°E, Spain), San Vito (40.60°N, 17.80°E, Italy), Athens (38.00°N, 23.50°E, Greece), and Nicosia, (35.03°N, 33.16°E, Cyprus). The outcomes demonstrate that: (1) IRIEup_re(V), performs better than ISP in the western Mediterranean (around Roquetes); (2) ISP performs slightly better than IRIEup_re(V) in the central part of Mediterranean (around Athens and San Vito); (3) ISP performance is better than the IRIEup_re(V) one in the eastern Mediterranean (around Nicosia); (4) IRIEup(NV) performance is worse than the IRIEup(V) one; (5) in the central Mediterranean area, IRIEup(V) performance is better than the IRIEup_re(V) one, and it is practically the same for the western and eastern sectors.Concerning the overall performance, nowcasting models proved to be considerably more reliable than the climatological IRI model to represent the ionosphere behaviour during geomagnetic-ionospheric storm conditions; ISP and IRIEup(V) provided the best performance, but neither of them has clearly prevailed over the other one.