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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Clinometric records with two long water levels in Lohja,Finland, during the total solar eclipse in 1990     

Jussi Kääriäinen 《Journal of Geodesy》1992,66(3):281-283

Two water tube clinometers are installed in a deep mine in Lohja, Finland. One, lying in an E-W direction, is 177 m long and the other, lying in a N-S direction, is 62 m long. These instruments are used for tidal records and research. Because the station was on the zone of totality of the 1990 solar eclipse, the instruments offered a suitable tool for investigating whether there was any shielding effect on the direction of the vertical. During the eclipse, the resolution of the instruments was increased to 0.00001 and 0.00004, respectively. p ]Recordings and data evaluation are discussed, and the results obtained show that no gravitational shielding was found at the level of the above accuracy.  相似文献   

Analysis of the color variability of ON 231 in 1994–2002     

V. A. Hagen-Thorn  E. I. Hagen-Thorn  L. O. Takalo  A. Sillanpää 《Astronomy Reports》2005,49(5):368-373

We analyze multicolor observations of the blazar ON 231 obtained during coordinated observations in 1994–2002. On average, the spectral energy distribution of the variable component in the optical range remains constant, and can be represented by the power law F _ν ∼ ν ^−0.85. Since the radiation of the blazar is strongly polarized, there is no doubt that the variable emission that is responsible for the activity of the blazar is synchrotron radiation. There are small but significant season-to-season variations in the spectral index.  相似文献   

Investigation of superstructures in mullite by high resolution electron microscopy and electron diffraction     

J. Ylä-Jääski  H.-U. Nissen 《Physics and Chemistry of Minerals》1983,10(2):47-54

Superstructures in synthetic mullite, Al_4+2x Si_2?2x O_10?x , prepared using the zone melting technique, are studied by high resolution electron microscopy (HREM), electron diffraction, and in situ energy dispersive X-ray spectroscopy. For x=0.40 composition HREM images indicate only short-range order. Near x=0.5 composition mullite has an antiphase domain structure with antiphase boundaries (APB's) oriented parallel to (100). For higher Al-content the APB's run in non-rational orientations which are slightly inclined against the {601}-planes. We propose models for the superstructures in which oxygen vacancies are arranged in channels parallel to the crystal b-axis. The models are supported by a one-to-one match between observed and computer-simulated images. An Al-rich limit of x=2/3 for mullite is deduced on the basis of stereochemical considerations. Different ordering schemes for the tetrahedral cations are believed to result in the orientation change of the APB's near x=0.5 composition.  相似文献   

Analysis of Multicolor Observations of 3C 66A in 1993-1998     

V. A. Hagen-Thorn  A. V. Hagen-Thorn  S. G. Jorstad  L. O. Takalo  A. Sillanpää  T. Pursimo  P. Boltwood 《Astrophysics》2001,44(3):283-291

The results of multicolor observations of the blazar 3C 66A, obtained in the course of the project OJ-94, are analyzed. It is established that the energy distribution of the variable source in the optical and IR ranges can be represented, on the average, by a power law: F ^-0.92. Since the blazar's emission is strongly polarized, there is no doubt of the synchrotron nature of the variable source responsible for the blazar's activity.  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   

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   

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   

HCO+ and13CO survey of CB and HHL objects     

R. A. Kandalian  P. Harjunpää 《Astrophysics》1993,36(1):6-11

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Estimation of pH optima and tolerances of diatoms in lake sediments by the methods of weighted averaging,least squares and maximum likelihood,and their use for the prediction of lake acidity   总被引：1，自引：0，他引：1  

Jari Oksanen  Esa Läärä  Pertti Huttunen  Jouko Meriläinen 《Journal of Paleolimnology》1988,1(1):39-49

Ecological optima and tolerances with respect to autumn pH were estimated for 63 diatom taxa in 47 Finnish lakes. The methods used were weighted averaging (WA), least squares (LS) and maximum likelihood (ML), the two latter methods assuming the Gaussian response model.WA produces optimum estimates which are necessarily within the observed lake pH range, whereas there is no such restriction in ML and LS. When the most extreme estimates of ML and LS were excluded, a reasonably close agreement among the results of different estimation methods was observed. When the species with unrealistic optima were excluded, the tolerance estimates were also rather similar, although the ML estimates were systematically greater.The parameter estimates were used to predict the autumn pH of 34 other lakes by weighted averaging. The ML and LS estimates including the extreme optima produced inferior predictions. A good prediction was obtained, however, when prediction with these estimates was additionally scaled with inverse squared tolerances, or when the extreme values were removed (censored). Tolerance downweighting was perhaps more efficient, and when it was used, no additional improvement was gained by censoring. The WA estimates produced good predictions without any manipulations, but these predictions tended to be biased towards the centroid of the observed range of pH values.At best, the average bias in prediction, as measured by mean difference between predicted and observed pH, was 0.082 pH units and the standard deviation of the differences, measuring the average random prediction error, was 0.256 pH units.  相似文献