X‐Ray observations of the Galactic Centre with Suzaku

We report on the diffuse X‐ray emission from the Galactic Centre (GCDX) observed with the X‐ray Imaging Spectrometer (XIS) on board the Suzaku satellite. The highly accurate energy calibration and extremely low background of the XIS provide many new facts on the GCDX. These are (1) the origin of the lines at 6.7 and 7.0 keV is collisional excitation in a hot plasma, (2) the discovery of new SNR and super‐bubble candidates, (3) most of the 6.4 keV line is X‐ray fluorescence, and (4) time variability of the 6.4 keV line is found from the Sgr B2 complex. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

A Study Of The Atmospheric Boundary Layer Using Radon And Air Pollutants As Tracers

Concentrations of radon ²²²Rn andair pollutants, meteorological parametersnear the surface and vertical profiles of meteorological elements were measured atUchio (Okayama City, Okayama Prefecture, Japan) 12 km north from the coast ofthe Inland Sea of Japan. In the nighttime, the ²²²Rn concentration increased in the case of weak winds, but did not increase as much in the case of moderate or strong winds, as had been expected. In the daytime, the ²²²Rn concentrationheld at a slightly higher than average level for the period from sunrise to about 1100 JST. It is considered that this phenomenon is due to a period of morning calm, that is, a transition period from land breeze to sea breeze.NO, which is sensitive to traffic volume,brought information concerning advection.Oxidant concentrations,which reflect the availability of sunlight,acted in the reverse manner to ²²²Rnconcentrations. Thus, a set of ²²²Rn and air pollutants could provide useful information regarding the local conditions of the atmospheric boundary layer.     

Classification et cartographie du paysage sur base écologique avec application à l'Italie

It is well known that although the geographic landscape and the ecosystem are both terrestrial units involving physical and biological components, including man and his activity, they are in nature extremely different. The geographic landscape is a complex of directly perceptible forms produced by the interaction (synergism) of three main components (synergizing) present in varying degrees and in unstable equilibrium (physical base, the biotic element and the results of human activity); whilst the ecosystem may not be directly perceived and is composed of a stable system of matter and energy, contained in the living and non-living parts of an environment, where exchanges between the two parts take place in a continuous flux (Odum, 1958). The geographic landscape is characterized by formal, structural aspects, whereas the ecosystem is, by nature, functional and biological and is dominated by two cycles, one of matter and the other of energy, within which man can be included in varying degrees. Ever since man began to alter the natural biological processes with his constructive, destructive and polluting activity, structures have emerged within the ecosystem which show local modifications in quality and energy imbalance. These have survived in the form of truncated anthropo-ecosystems (Delpoux, 1972), where the artificially interrupted trophic chain survives with a disturbed energy balance. Imbalances are caused by alterations which are difficult to perceive directly in ecosystems, but are observable in landscapes which have been modified in response to such changes. The ecosystem must, therefore, be considered a determinant of landscape. Hence it is possible to distinguish fairly precisely the existence of different types of landscape on the basis of the material and energy balance of their associated ecosystems where ecosystem and geographic landscape are closely linked by cause and effect. Hence the term landscape ecology (Landschaftsöcologie;Troll, 1939) where the term “ecology” is taken to mean “the functional study of the dynamics of a system of action, determining landscape” (Schmithüsen, 1973). If the energy balance and the natural and human transformations of ecosystems are jointly considered, it is possible to obtain a significant ecologically based landscape classification. The first category is that of ecologically balanced landscapes, within which transfer phenomena are cyclic as energy, or even matter, are completely utilized by their biological constituents. This applies to all natural landscapes, even those with a dominant natural factor, that are unaffected by human action; their limits can therefore be considered similar to those of natural ecosystems. Amongst these can also be included areas with a gathering economy and primitive and subsistence farming. By contrast with these is the category of ecologically unbalanced landscapes where the presence of man in the environment has transformed natural ecosystems into anthropoecosystems with different characteristics. Two types can be distinguished, one hyperenergetic with a positive energy balance and thus an exporter of energy, the other hypoenergetic characterised by a negative energy balance,and thus importing energy (Delpoux, 1972). In hyperenergetic landscapes man intervenes with advanced agriculture and animal husbandry and thus transforms in different ways and in varying degrees the natural setting. They therefore include agrobiosystems, typical of specialized agriculture, intensive polyculture and plantation monoculture, and trophobiosystems typical of rationalized animal husbandry. Both produce vegetable and animal foods for the market. In hypoenergetic landscapes, the production of organic substances with an energy value becomes increasingly deficient, so that the biological community has to become dependent on external contributions; they mainly occur in high density population landscapes with low productivity rural activities due to poor natural conditions, poor organization, or a high degree of urban and industrial development. To these categories, which are mainly dependent on the ratio of population to resources, can be added that of degraded landscapes or ecosystems, caused by natural degradation (exogenous or endogenous) or by pollution and despoliation (biological and mineral) caused by human activity. Then follow landscapes with artificial or substitution ecosystems (urban or industrial) the elements of which are characteristically formal in appearance. The last category is that of ecologically integrated and complex landscapes, the result of the combination of two or more different ecological aspects (rural and urban, and, for example, outside this group, rural and industrial, agricultural and moderately urbanized) which interdigitate and encroach upon each other. On the basis of this classification, it is possible to discern the distinguishing features typical of landscapes and thus our ability to delimit their extent on maps. They have been applied in the production of an ecologically based landscape map of Italy at an original scale of 1:1,500,000, a reduced black-and-white version of which has been reproduced in the main body of this paper. As a first attempt at such a representation it is both adequate and useful and provides a basis for further work and analysis. The exercise confirms that the consideration of landscape, especially humanized landscape, in an ecological perspective, supplies important information for the interpretation of its structure from a functional and physiological stand-point, as well as for the understanding of its dynamics. It also facilitates the consideration of the environment as a whole, presenting more effectively the problems of its evaluation and consequently adds to our appreciation of its economic and social significance.     

Cosmic ray sidereal diurnal variation of galactic origin observed by neutron monitors

We have analyzed the sidereal diurnal variation of cosmic rays, using 620 station-years of neutron monitor data during the period 1958–1979. The sidereal variation averaged over the period for all the stations in the Northern Hemisphere is different from the corresponding variation in the Southern Hemisphere. The difference is statistically significant and can be identified with the spurious sidereal variation produced from the stationary anisotropy of solar origin, responsible for the solar semi-diurnal variation. The variation common to both hemispheres is also exceptionally significant from the statistical point of view and could be regarded as being due to a uni-directional galactic anisotropy. This variation has an amplitude of 0.0204 ± 0.0015% and a phase of 6.8 ± 0.3 h and is clearly different from that ( ～ 0.05%, 0 ～ 3 h) observed in the high rigidity region (500 ～ 10⁴ GV). The physical meaning of the variation is discussed from the standpoint of the heliomagnetospheric modulation of galactic anisotropy.     

Seismic and ground deformation crises at Rabaul Caldera: Prelude to an eruption?

A dramatic short-term increase in seismicity and ground deformation took place at Rabaul Caldera on 19 September 1983, and marked the start of a period of frequent episodes of high seismic energy release and concurrent rapid ground deformation. Together with increased background levels of seismicity and ground deformation, these phenomena are interpreted as indications of higher rates of magma injection at shallow depths within the caldera, which greatly increases the likelihod of an eruption at Rabaul in the near future. A modest volume of magma, about 100 million m³, could be available for eruption from two shallow reservoirs, but a somewhat deeper and much larger magma body — residual from the latest major eruption about 1400 yr BP — may also exist beneath the caldera.     

Monitoring Quiescent Volcanoes by Diffuse CO2 Degassing: Case Study of Mt. Fuji, Japan

Since the 8th century, more than seventeen eruptions have been recorded for the Mt. Fuji volcano, with the most recent eruption occurring in 1707 (Hoei eruption). For the past 300 years the volcano has been in a quiescent stage and, since the early 1960s, has exhibited neither fumarolic nor thermal activity. However, the number of low-frequency earthquakes with a hypocentral depth of 10–20 km increased significantly beneath the northeastern flank of Mt. Fuji in 2000–2001, suggesting a possible resumption of magmatic activity. In this study, diffuse CO₂ efflux and thermal surveys were carried out in four areas of the volcano in 2001–2002 in order to detect possible signs of the upward movement of deep magma. At all survey points, the CO₂ efflux was below the detection limit with the exception of a few points with biological CO₂ emission, and ground temperatures at a depth of 20–30 cm were below ambient, indicating no surface manifestations of gas or heat emission. Should magma rise into the subsurface, the diffuse CO₂ efflux would be expected to increase, particularly along the tectonically weakened lineation on the Mt. Fuji volcano, allowing for the early detection of pre-eruptive degassing.     

Analysis of freak wave measurements in the Sea of Japan

This paper presents an analysis of a set of available freak wave measurements gathered from several periods of continuous wave recordings made in the Sea of Japan during 1986–1990 by the Ship Research Institute of Japan. The analysis provides an ideal opportunity to catch a glimpse of the statistics of freak waves in the ocean. The results show that a well-defined freak wave may occur in the developed wind–wave condition: S(f)∝f⁻⁴, with single-peak directional spectra. The crest and trough amplitude distributions of the observed sea waves including freak waves are different from the Rayleigh distribution, although the wave height distribution tends to agree with the Rayleigh distribution. Freak waves can be readily identified from the wavelet spectrum where a strong energy density occurs in the spectrum, and is instantly surged and seemingly carried over to the high-frequency components at the instant the freak wave occurs.     

Occurrence probability of a freak wave in a nonlinear wave field

The Edgeworth’s form of a cumulative expansion of the probability density function (PDF) of surface elevation expands the maximum wave height distribution to predict the occurrence probability of freak waves. This study investigated the enhancement of the occurrence probability of freak waves due to the fourth order moment of surface elevation, kurtosis, change and found that the nonlinear effects on the occurrence probability of a freak wave linearly depends on kurtosis for a small number of waves N=250. The statistical theory was compared with field data, and freak waves sometimes appear when not expected by the Rayleigh theory, but they were predicted by the proposed theory.     

Effects of wave breaking on wave statistics for deep-water random wave train

The experimental studies of the breaking effects on wave statistics for deep-water random waves are presented. It is especially focused on the behavior of kurtosis of surface elevations due to wave breaking. Wave breaking suppresses the maximum limit of kurtosis of the surface elevation, although skewness depends on characteristic wave steepness. The mean instantaneous wave steepness of breaking waves defined using the zero-down-crossing method was much lower than expected from the Stokes waves.     

Biomarkers for endocrine disruptors in three species of Mediterranean large pelagic fish

The hypothesis that Mediterranean top predator species, such as large pelagic fish, are potentially at risk due to endocrine disrupting chemicals (EDCs), is investigated. The potential estrogenic effects of PHAHs in three fish species of commercial interest, the top predators bluefin tuna (Thunnus thynnus thynnus), swordfish (Xiphias gladius), and Mediterranean spearfish (Tetrapturus belone), were investigated using vitellogenin (Vtg), zona radiata proteins (Zrp) and mixed function oxidases (EROD, BPMO) as diagnostic tools. High induction of Vtg and Zrp was detected by western blot and ELISA techniques in adult males of X. gladius and T. thynnus thynnus, suggesting that these species are at high toxicological risk in the Mediterranean sea. Comparison of BPMO and EROD activities in the three species indicated, both in male and female, much higher MFO activity in bluefin tuna. This data suggests high exposure of this species to lipophilic xenobiotic contaminants in the Mediterranean environment.