Consequences of growth variation in northern Baltic herring for assessment and management     

Rahikainen  Mika; Stephenson  Robert L. 《ICES Journal of Marine Science》2004,61(3):338-350

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Industrial minerals and rocks, aggregates and natural stones in the Nordic countries     

Kurt Johansson Rune B. Larsen Markku J. Lehtinen Lars Persson Mika Raeisaenen Stig A. Schack Pedersen Paer Weihed Nils-Gunnar Wik 《《幕》》2008,31(1):133-139

The Nordic countries, including Greenland, have a long tradition in mining. The industrial minerals sector is expanding in most Nordic countries and extensive development has taken place during the last few years. The main commodities mined are carbonate rocks, quartz, feldspar, apatite, olivine and talc.
A number of diferent types of dimension stones are quarried in all countries. Rock aggregates are increasingly important, replacing sand and gravel aggregate as construction materials in some countries due to the need to protect ground water supplies.  相似文献   

An objective classification system of air mass types for Szeged, Hungary, with special interest in air pollution levels     

L. Makra  J. Mika  A. Bartzokas  R. Béczi  E. Borsos  Z. Sümeghy 《Meteorology and Atmospheric Physics》2006,92(1-2):115-137

Summary This paper determines the characteristic air mass types over the Carpathian Basin for the winter (December, January, and February) and summer (June, July and August) months dependant on levels of the main air pollutants. Based on the ECMWF data set, daily sea-level pressure fields analysed at 00 UTC were prepared for each air mass type (cluster) in order to relate sea-level pressure patterns with the level of air pollutants in Szeged. The data comprise daily values of twelve meteorological and eight pollutant parameters for the period 1997–2001. Objective definition of the characteristic air mass types is achieved by using the methods of Factor Analysis and Cluster Analysis. According to the results, during the winter months five air mass types (clusters) were detected based on higher concentrations of primary pollutants that occur with high irradiance and low wind speed. This is the case when an anticyclone is found over the Carpathian Basin and over the region south of Hungary, influencing the weather of the country. Low levels of pollutants occur when zonal currents exert influence over Hungary. During the summer months anticyclones and anticyclone ridge situations are found over the Carpathian Basin. (During the prevalence of anticyclone ridge situations, the Carpathian Basin is found at the edge of a high pressure centre.) As a result of high irradiance and very low NO levels, secondary pollutants are highly enriched.  相似文献   

Giant bow shock pairs associated with herbig-haro jets     

Katsuo Ogura 《Astrophysics and Space Science》1995,224(1-2):151-154

Two pairs of giant (linear size 1 pc) bow shock structures have been discovered, each located symmetrically about HH 1/2 and HH 124. Their Herbig-Haro (HH) natures have been confirmed by narrow band CCD imaging on and off [SII] 6717/6731 and/or slit spectroscopy. Multiple bow shocks are known associated with a few HH objects such as HH 34, and are interpreted as evidence for recurrent outflow activity of the exciting sources. The giant bow shocks associated with HH 1/2 or HH 124 provide further, beautiful examples of this phenomenon and, with dynamical ages of nearly 20000 yr in both pairs, extend its timescale by more than an order of magnitude.  相似文献   

Ecological conflicts in Poland   总被引：1，自引：0，他引：1  

Włodzimierz Kurek  Robert Faracik  Mirosław Mika 《GeoJournal》2001,55(2-4):507-516

Transformation of the political system, observed in Poland for 10 years in connection with economic restructuring and basic socio-economic reforms to harmonise with European Union structures, is also evident in terms of environmental management. Pollution has been reduced in many ways but the rise in living standards, linked with the rapid growth of cars and other forms of consumption, has had a negative effect and environmental conditions have deteriorated in the central areas of large cities. The growth of waste water and refuse is a considerable problem. More areas are now officially protected and the three levels of local government established at the beginning of January 1999 (voivodeship, district and community) all have certain defined environmental protection responsibilities which are cumulatively greater than before. Meanwhile there is a greater awareness in society of environmental issues, although it does not yet lead to a high level of participation in protection work. However, there are strongly-expressed opinions on the ecological acceptability of certain economic developments and conflicts are frequently arising within communities and local governments and also between investors on the one side and ecological organisations and environmental protection institutions on the other. Most controversial are new roads, power stations (like the Zarnowiec nuclear project) and reservoirs like the one on the Dunajec river at Czorsztyn. Local communities frequently resist plans for waste dumps, incinerating plants and other developments which are seen as injurious to health or the quality of life. The planned reprivatisation of the state-owned forests is also criticised by foresters and ecological movements. Conflicts are likely to grow as economic development accelerates but better information and greater public understanding of the need for sustainability should make for consensus. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Mesozoic radiolarians and radiolarian-bearing sequences in the circum-Pacific regions: A report of the symposium-'Radiolarians and Orogenic Belts'     

Atsushi  Matsuoka  Yoshiaki  Aita  Munasri  Koji  Wakita  Gaoping  Shen  Hiroshi  Ujilé  Katsuo  Sashida  Valentina S.  Vishnevskaya  Nkita Y.  Bragin Fabrice  Cordey 《Island Arc》1996,5(2):203-213

Abstract This paper contains extended abstracts of the seven papers presented at the symposium 'Radiolarians and Orogenic Belts' held at the seventh meeting of the International Association of Radiolarian Paleontologists (INTERRAD). Important results of the symposium include the following: (1) Upper Paleozoic and Mesozoic cherts are widely distributed within accretionary complexes in the circum-Pacific orogenic belt. Radiolarian dating reveals that long durations of chert sedimentation in a pelagic environment are recorded on both sides of Pacific-rim accretionary complexes (e.g. New Zealand, Japan, Russian Far East, Canadian Cordillera). (2) Triassic radiolarian faunas from New Zealand and the Omolon Massif, northeast Siberia are similar in composition and are characterized by the absence of typical Tethyan elements. This suggests that radiolarian faunal provincialism may have been established as early as the Triassic. High-latitude radiolarian taxa exhibit a bi-polar distribution pattern. (3) The Lower Triassic interval in chert dominant pelagic sequences is mechanically weaker than other levels and acted as a décollement in accretionary events. This lithologic. contrast in physical property is considered to reflect radiolarian evolution, such as the end-Permian mass extinction.  相似文献   

Nucleation,growth and stability of CaAl2Si2O8 polymorphs     

Toshiya Abe  Katsuo sukamoto  Ichiro Sunagawa 《Physics and Chemistry of Minerals》1991,17(6):473-484

By means of in situ observation, the nucleation and growth of triclinic, pseudo-orthorhombic and pseudo-hexagonal CaAl₂Si₂O₈ were investigated and their relative stabilities established. Pseudo-hexagonal and pseudo-orthorhombic CaAl₂Si₂O₈ nucleate prior to anorthite and grow in a supercooled anorthite melt before the latter appears. They either dissolve or transform to anorthite once the latter nucleates and starts to grow. Corundum and mullite also nucleate metastably prior to anorthite in this melt. The liquidus temperatures of the four metastably nucleated phases were determined precisely by in situ measurements of the transformation temperatures from a polyhedral to a rounded morphology. On the basis of the supercooling thus determined, the growth rate versus supercooling relations were measured and analysed for the respective phases. The growth rate of the stable phase is one order of magnitude higher than those of any metastable phases. However, the growth rates of the three CaAl₂Si₂O₈ polymorphs normalized by the viscosities are nearly the same.  相似文献   

Subarctic catchment water storage and carbon cycling – Leading the way for future studies using integrated datasets at Pallas,Finland     

Hannu Marttila  Annalea Lohila  Pertti Ala-Aho  Kashif Noor  Jeffrey M. Welker  Danny Croghan  Kaisa Mustonen  Leo-Juhani Meriö  Anna Autio  Filip Muhic  Hannah Bailey  Mika Aurela  Jussi Vuorenmaa  Timo Penttilä  Valtteri Hyöky  Eric Klein  Anton Kuzmin  Pasi Korpelainen  Timo Kumpula  Anssi Rauhala  Bjørn Kløve 《水文研究》2021,35(9):e14350

Subarctic ecohydrological processes are changing rapidly, but detailed and integrated ecohydrological investigations are not as widespread as necessary. We introduce an integrated research catchment site (Pallas) for atmosphere, ecosystems, and ecohydrology studies in subarctic conditions in Finland that can be used for a new set of comparative catchment investigations. The Pallas site provides unique observational data and high-intensity field measurement datasets over long periods. The infrastructure for atmosphere- to landscape-scale research in ecosystem processes in a subarctic landscape has recently been complemented with detailed ecohydrological measurements. We identify three dominant processes in subarctic ecohydrology: (a) strong seasonality drives ecohydrological regimes, (b) limited dynamic storage causes rapid stream response to water inputs (snowmelt and intensive storms), and (c) hydrological state of the system regulates catchment-scale dissolved carbon dynamics and greenhouse (GHG) fluxes. Surface water and groundwater interactions play an important role in regulating catchment-scale carbon balances and ecosystem respiration within subarctic peatlands, particularly their spatial variability in the landscape. Based on our observations from Pallas, we highlight key research gaps in subarctic ecohydrology and propose several ways forward. We also demonstrate that the Pallas catchment meets the need for sustaining and pushing the boundaries of critical long-term integrated ecohydrological research in high-latitude environments.  相似文献   

Seasonal variations of organic carbon and nitrogen in the upper basins of Yangtze and Yellow Rivers     

Xiang-ying Li  Yong-jian Ding  Tian-ding Han  Jian-zhong Xu  Shi-chang Kang  Qing-bai Wu  Mika Sillanpää  Zhong-bo Yu  Cong-rong Yu 《山地科学学报》2017,14(8):1577-1590

The profound impacts exerted by climate warming on the Tibetan Plateau have been documented extensively, but the biogeochemical responses remain poorly understood. This study was aimed at seasonal variations of total organic carbon (TOC) and total organic nitrogen (TON) in stream water at two gauging sections (TTH, ZMD) in the upper basin of Yangtze River (UBYA) and at four gauging sections (HHY, JM, JG, TNH) in the upper basin of Yellow River (UBYE) in 2013. Results showed that concentrations of TON exhibit higher values in spring and winter and lower values in summer. TOC exhibits higher concentrations in spring or early summer and lower concentrations in autumn or winter. Seasonal variations of TOC and TON fluxes are dominated by water flux. In total, the UBYE and UBYA delivers 55,435 tons C of organic carbon and 9,872 tons N of organic nitrogen to downstream ecosystems in 2013. Although the combined flux of TOC from UBYA and UBYE is far lower than those from large rivers, their combined yields is higher than, or comparable with, those from some large rivers (e.g. Nile, Orange, Columbia), implying that organic carbon from the Tibetan Plateau may exert a potentially influence on regional and/or global carbon cycles in future warming climate.  相似文献   

Crystallization of cosmic dust from highly supersaturated silicate vapor in a rapidly cooled environment     

Hidekazu Kobatake  Katsuo Tsukamoto  Ken Nagashima  Peter Dold 《Icarus》2008,198(1):208-217

Growth conditions and the resultant morphology of cosmic forsterite and enstatite particles condensed from the vapor were investigated experimentally as a function of growth temperature and supersaturation using flash-heating by CO₂ laser irradiation. Forsterite particles grew dominantly, followed by a few pyroxenes. No silica minerals were observed. The forsterite morphology changed systematically depending on the temperature (T) and the vapor supersaturation (σ). As the temperature decreased and the vapor supersaturation increased, the forsterite morphology changed from a bulky type (T=1000-1450 °C, σ<97) to a platy type (T=700-1000 °C, σ=97-161), then to a columnar needle shape (T=500-820 °C, σ=131-230), and finally to a droplet type (T<500 °C, σ>230). Very thin polygonal growth steps, which suggest vapor-solid (VS) growth, were detected on the surface of the faceted bulky and platy forsterite particles. Transmission electron microscopic (TEM) observation showed that the tip of the columnar and needle-shaped forsterite was covered with an amorphous layer. This amorphous coverage illustrates that a liquid phase can be condensed from the vapor, even under the stable conditions where crystalline forsterite is stable. This amorphous layer plays a role in the vapor-liquid-solid (VLS) mechanism of the forsterite particles. The difference in the growth mechanism as a function of vapor supersaturation and temperature can be explained by metastable liquid condensation. The experimentally synthesized coexisting patterns of VS-grown and VLS-grown olivine particles resemble the pattern of matrix olivine or chondrule rims in primitive meteorites. Forsterite can crystallize more easily than either pyroxene or silica minerals, which is consistent with the dominance of forsterite in cometary dust particles, as suggested by its infrared spectrum.  相似文献