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The deviation from thermodynamic equilibrium of the ion velocity distribution functions (VDFs), as measured by the Magnetospheric Multiscale (MMS) mission in the Earth’s turbulent magnetosheath, is quantitatively investigated. Making use of the unprecedented high-resolution MMS ion data, and together with Vlasov–Maxwell simulations, this analysis aims at investigating the relationship between deviation from Maxwellian equilibrium and typical plasma parameters. Correlations of the non-Maxwellian features with plasma quantities such as electric fields, ion temperature, current density and ion vorticity are found to be similar in magnetosheath data and numerical experiments, with a poor correlation between distortions of ion VDFs and current density, evidence that questions the occurrence of VDF departure from Maxwellian at the current density peaks. Moreover, strong correlation has been observed with the magnitude of the electric field in the turbulent magnetosheath, while a certain degree of correlation has been found in the numerical simulations and during a magnetopause crossing by MMS. This work could help shed light on the influence of electrostatic waves on the distortion of the ion VDFs in space turbulent plasmas.
The Universe is permeated by hot, turbulent, magnetized plasmas. Turbulent plasma is a major constituent of active galactic nuclei, supernova remnants, the intergalactic and interstellar medium, the solar corona, the solar wind and the Earth’s magnetosphere, just to mention a few examples. Energy dissipation of turbulent fluctuations plays a key role in plasma heating and energization, yet we still do not understand the underlying physical mechanisms involved. THOR is a mission designed to answer the questions of how turbulent plasma is heated and particles accelerated, how the dissipated energy is partitioned and how dissipation operates in different regimes of turbulence. THOR is a single-spacecraft mission with an orbit tuned to maximize data return from regions in near-Earth space – magnetosheath, shock, foreshock and pristine solar wind – featuring different kinds of turbulence. Here we summarize the THOR proposal submitted on 15 January 2015 to the ‘Call for a Medium-size mission opportunity in ESAs Science Programme for a launch in 2025 (M4)’. THOR has been selected by European Space Agency (ESA) for the study phase.
Wolbachia, belonging to Alphaproteobacteria, is ubiquitously found in arthropods and filarial nematodes, and is known to manipulate the reproduction of its hosts in various ways, such as feminization, male killing, induction of parthenogenesis or induction of cytoplasmic incompatibility. We found that the Wolbachia infection frequencies of the butterfly Colias erate poliographus were high (85.7–100%) in seven Japanese populations. Crossing experiments and rearing revealed that the Wolbachia strain exhibited strong cytoplasmic incompatibility and perfect vertical transmission in C. erate poliographus. Moreover, a comparison of the survival rates between infected and cured broods suggested that Wolbachia infection had beneficial effects on host fitness. Our findings suggested that the high infection frequencies in Japanese populations have been accomplished by these advantageous traits of the Wolbachia strain. Furthermore, the multilocus sequence typing (MLST) scheme revealed that the Wolbachia in C. erate poliographus is a novel strain (ST141), belonging to supergroup B.
The FIRBE (Far-Infrared Balloon-Borne Experiment) pro ject is focused on mapping of the far-infrared emission from the Galaxy and external galaxies with the same spatial resolution as that of the IRAS.
Two dimensional array on a low emissivity telescope is a powerful facility for wide-area survey.
A comprehensive study of ice-crystal fabrics and textures was conducted on the Dome F (Antarctica) ice core. Crystal ,-axis orientations, crystal sizes and crystal shape were measured on thin sections with an automatic ice-fabric analyzer. The general feature of textural and fabric development through a 2500 m long core was obtained by a 20 m interval study. Crystal size steadily increases with depth except for depths of about 500,1800, 2000, 2200 and 2300 m, at which depths crystal size decreases suddenly. There is a clear correlation between crystal-size and ´18O values. Crystals tend to elongate horizontally with depth, and the aspect ratio (long axis vs short axis of a grain) increases twofold at 1600 m depth and fluctuates below that depth. The .-axis orientation fabrics gradually change with depth from a random orientation pattern near the surface to a strong vertical single maximum at 2500 m. These are very similar to those from the GRIP (Greenland) core The observations of crystal shape and the fabric measurements indicate that nucleation-recrystallization does not take place at Dome F.
An X-ray transmission method has been developed to obtain a continuous profile of bulk densities of ice cores. Intensities of X-rays transmitted through an ice-core sample were continuously measured by an X-ray detector during translation of the sample across the X-ray beam. A thick section of an ice core with a constant thickness was prepared by band-sawing followed by microtome planing. The X-ray intensity profile obtained was converted to a density profile using a calibration curve for X-ray absorption vs ice thickness. Using this method, spatial resolution of the density profile was down to 1 mm. X-ray radiographs were also taken on a two-dimensional detector imaging plate, in order to observe layer structures of the ice cores.
The method was applied to Dome Fuji (Antarctica) ice cores from the surface to 110 m depth. From the density profile obtained we calculated the power spectrum of the density variation by the discrete Fourier transform, and obtained several peaks at different frequencies. The center period in the spectrum was close to the annual accumulation thickness at the drill site.
Background. Although many case–control
studies have replicated an association between
dysfunctional parenting and a lifetime diagnosis of depression,
few epidemiological studies have
explored the association. In addition, little is known about the
association in non-western countries.
Methods. Using logistic regression analyses, additive and
interactive contributions of parental child-rearing behaviours, as
measured by the Parental Bonding Instrument (PBI), toward the risk for
having a lifetime diagnosis of major depressive disorder were explored
in 418 employed Japanese
adults. The diagnosis was provided by using the Inventory to Diagnose
Depression, lifetime version.
The analyses were conducted for male and female subjects separately.
Results. Parental care rather than parental protection
was primary in predicting lifetime depression
in both male and female subjects. An interactive combination of low care
and high protection
(‘affectionless control’) was a significant risk factor
for lifetime depression in male respondents'
reporting child-rearing behaviours of both parents and female
respondents' reporting paternal
child-rearing behaviours. Model improvements when entering the PBI scores
were larger in male
subjects than in female subjects.
Conclusions. The results suggested that a combination of
low care and over-protection increases a
risk to lifetime depression even in a non-clinical sample; that an
association between dysfunctional
parenting (particularly low care) and the development of depression is
independent of culture; and
that Japanese boys are more sensitive than Japanese girls to
dysfunctional parenting as regards the development of depression.
Compact, efficient, spectroscopic detector arrays which preferably operate without cooling have applications in the fields of x-ray astronomy, nuclear medicine and radioactive materials management. We have fabricated a 16 element CdZnTe detector array that provides a stopping efficiency of greater than 80%, a photopeak fraction of 44% and an energy resolution of 3.2 keV FWHM at 122 keV. The 4 × 4 array uses a pixel size of(1.5 mm)2 with 0.2 mm spacing on a 5 mm thick substrate. The variation in spectroscopic properties amongst pixels has been characterized in terms of energy resolution and detection efficiency. Operation in current (or flux) mode for transmission imaging has also been investigated.
Horizontal and vertical distributions of melt features (ice layers) were examined using two ice cores (206.6 and 101.5 m deep, 1 m apart) from Site J (66°51.9′ N, 46°15.9′W, 2030 m a.s.l.). The temperature at 10 m was −16.3°C. We observed 2804 melt features, with a total thickness of 30.32 m, in the 206.6 m core, corresponding to 16.4% by volume of the ice-equivalent core length. Horizontal distribution of melt features was examined by correlating melt-feature thicknesses in the two cores. The correlation coefficient was 0.71 (n = 514) for each melt feature in the two cores. It was maximum for data passed through 5 and 40 year low-pass filters. A significant relationship (P = 0.005, n = 36) was obtained for the vertical distribution of melt features and the June temperature on the west coast of Greenland (Jakobshavn). Using this, June temperatures at Jakobshavn since 1550 were estimated. There are three periods (1685-1705, 1835-70 and 1933-45) during which mean June temperatures clearly decreased, when they were estimated to he 0.1°, 0.4° and 0.2°C lower than the average for the whole period (1550-1989). The first two “cold” periods have been identified in melt features of the Dye 3 and Devon Island ice cores and in a tree-ring profile from Yukon Territory, Canada. Melt-feature percentages in the Site J ice core have increased since about 1945, probably reflecting summer-temperature warming on the ice sheet.
Between May 1983 and July 1984 glaciological parties of the 24th and 25th Japanese Antarctic Research Expeditions (JARE–24 and 25) carried out ice-core drilling using a thermal drill, down to 700.5 m depth at Mizuho Station (70°41'53"S, 44°19'54"E), as a part of the Glaciological Research Program in east Dronning Maud Land, Antarctica.
The thermal drill, 3.9 m long and capable of taking a core 1.5 m long and 130 mm in diameter, is an improved version of a drill used by JARE–15 in 1975. The most important improvement was the monitoring system during drilling, for which a micro-computer was fitted in the drill. By using this system, such accidents as heater burn-out, tank overflow and failure of water suction would immediately be brought to our attention. The drilling speed was about 1.6 m/h, when the optimum output was 3.6 kW. The core recovery rate was above 99%.
The core quality was good down to a depth of 80 m. Between 80 and 120 m, cracks were found at intervals of 0.15–0.5 m, and horizontal cracks were found continuously at intervals of 0.01 m or less.
Immediately after the core was pulled, the stratigraphy was observed and bulk density was measured. A dust band, presumably volcanic particles, was seen at only 500.2 m depth during stratigraphic observation. The following analyses were carried out at Mizuho Station within a month of recovery:
(1) Density determination by the hydrostatic method.
(2) Measurement of total gas content.
(3) Thin-section analyses, including observation of cracking around air bubbles and the crystalline texture, and ice-fabric studies.
The 700.5 m core has been brought to Japan, and the following analyses are now under way:
(1) Oxygen-isotope ratio.
(2) Concentration of microparticles.
(3) Electric conductivity.
(4) Chemistry of soluble impurities.
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