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851.
The cod stocks in the Baltic Sea are important not only for fisheries but for the entire ecosystem utilized by numerous stakeholders around the coast. All such activities have economic values. In this note the economics of the Swedish Baltic Sea cod fishery is estimated in relation to the sector's interaction with other users of the Baltic Sea ecosystem. The results show a negative resource rent for the fishery, € −5 million without public expenses (subsidies and administrative costs), and € −13 million including public expenses. The interactions between the fisheries and tourism, seal population, carbon dioxide emissions, recreational fishing, and discards are discussed, and when monetary estimates are available these are related to the estimated resource rent. 相似文献
852.
853.
Castillo Yvelice Pais Maria Alexandra Fernandes João Ribeiro Paulo Morozova Anna L. Pinheiro Fernando J. G. 《Solar physics》2021,296(7):1-30
Solar Physics - During solar minimum, the Sun is relatively inactive with few sunspots observed on the solar surface. Consequently, we observe a smaller number of highly energetic events such as... 相似文献
854.
Haldo Vedin Anna Eklund & Hans Alexandersson 《Geografiska Annaler: Series A, Physical Geography》1999,81(3):361-368
The flood at Mount Fulufjället, 30-31 August 1997 was caused by the most furious rainstorm ever documented in Sweden. Private measurements on the mountain show not less than 276 mm over 24 hours, and the distribution of severe damage suggests even higher amounts in other parts of the mountain. The precipitation was connected to a front attacking a high pressure that had been dominating the weather in Sweden for several weeks, but orographic lifting on the east-facing slopes of the mountain may partly have caused the extreme intensity. In River Fulan, one of the upper branches of River Dalälven, the discharge peaked at a diurnal mean value of 233 m 3/s;, the highest since measurements began in 1913. At the stream Tangån and the new common outlet of the streams Stora and Lilla Göljån, both locations with a normal discharge of only around 1 m 3/s, instantaneous values of approximately 300 m 3/s have been estimated, corresponding to values close to the normal discharge at the mouth of River Dalälven on the coast of the Sea of Bothnia. 相似文献
855.
856.
Paolo Farinella Andrea Milani Anna M. Nobili Paolo Paolicchi Vincenzo Zappalà 《Icarus》1983,54(2):353-360
Hyperion is an irregularly shaped object of about 285 km in mean diameter, which appears as the likely remmant of a catastrophic collisional evolution. Since the peculiar orbit of this satellite (in resonance locking with Titan) provides an effective mechanism to prevent any reaccretion of secondary fragments originated in a breakup event, the present Hyperion is probably the “core” of a disrupted precursor. This contrasts with the other, regularly shaped small satellites of Saturn, which, according to B.A. Smith et al. [Science215, 504–537 (1982)], were disrupted several times but could reaccrete from narrow rings of collisional fragments. The numerical experiments performed to explore the region of the phase space surrounding the present orbit show that most fragments ejected with a relative velocity rapidly attain chaotic-type orbits, having repeated close encounters with Titan. Ejection velocities of this order of magnitude are indeed expected for a collision at a velocity of ~ 10 km/sec with a projectile-to-target mass ratio of the order of 10?3; similar effects could be produced by less energetic but nearly grazing collisions. Such events are not likely to displace the largest remnant (i.e., the present Hyperion) outside the stable region of the phase space associated with the resonance, but could be responsible for the large amplitude of the observed orbital libration. 相似文献
857.
858.
Summary Regular measurements of the dust and nuclei content of the air near the ground at Poona were made during 1967–69 to study the characteristic elements of natural pollution near the ground, its origin and its variation with time, seasons and altitude. The electrical field strength, the positive and negative polar conductivities of the air and the number of positively and negatively charged small ions in the atmosphere near the ground were also measured at the same time. These measurements were repeated at two mountain stations during February, March, and June 1969. The dust content and the electric field show seasonal and diurnal variations opposite to those of the small ion density and electrical conductivity. Thus while the electric field is a maximum in winter, the conductivity and small ion content is a maximum during the monsoon months and the dust content a maximum in the premonsoon summer months. A marked increase in the electric field and the dust and condensation nuclei content is observed since similar measurements were last made in 1935–37 at Poona, with a corresponding decrease in small ion count and conductivity. These large variations are associated with the increased industrialization and urbanization of the regions round Poona during the last thirty years.
Zusammenfassung In den Jahren 1967 bis 1969 wurden in Poona regelmässige Messungen der Staub-und Kernzahlen in der bodennahen Atmosphäre ausgeführt, um die charakteristischen Elemente der bodennahen Pollution, ihrer Herkunft und ihren Änderungen im Lauf der Zeit, der Jahreszeiten, und der Höhe zu studieren. Gleichzeitig wurden auch die luftelektrische Feldstärke, die positiven und negativen polaren Leitfähigkeiten, und die Konzentration der positiven und negativen schnellen Ionen in der bodennahen Luft gemessen. Im Februar, März, und Juni 1969 wurden diese Messungen an zwei Bergstationen wiederholt. Staubgehalt und luftelektrisches Feld zeigen Jahresgänge und Tagesgänge welche zu denen der Leitfähigkeiten und der Ionenzahlen entgegengesetzt verlaufen. Demnach sind, während das luftelektrische Feld seinen Höchstwert im Winter erreicht, luftelektrische Leitfähigkeit und Ionenzahlen während der Monsunmonate am grössten; der Staubgehalt hat seinen Höchstwert in den Sommermonaten vor der Monsunzeit. Seit ähnliche Messungen zum letzten Male in Poona ausgeführt wurden, 1935 bis 1937, ist die Konzentration der Kerne und der Wert des luftelektrischen Feldes merklich angestiegen, während Kleinionenzahlen und Leifähigkeit entsprechend zurückgegangen sind. Diese starken Veränderungen werden mit der in den letzten dreissig Jahren angewachsenen Industrialisierung und Verstädterung der Gegend um Poona in Zusammenhang gebracht.相似文献
859.
Anna Hietanen 《Contributions to Mineralogy and Petrology》1971,30(2):161-176
Distribution of major and minor elements has been determined for five hornblende-biotite pairs from hornblende-biotite quartz diorite and monzotonalite and for a clinopyroxene-orthopyroxene pair from pyroxene diorite collected from the border zones and centers of zoned plutons in the northern Sierra Nevada, California. The distribution coefficients K
d
[Mg/Fe] for biotite/hornblende are of the same magnitude (0.61–0.67) for both the mafic border zone and the silicic center.For comparison, K
D
[Mg/Fe] values for biotite/hornblende from plutonic rocks of the central Sierra Nevada and the southern California batholith were calculated from data published by others. Rocks of the oldest age group (ca. 150 m.y.) in the central Sierra Nevada have an average distribution coefficient, K
D
, of 0.64, close to the average K
D
in the study area, where K-Ar dates are 143 to 129 m.y. The intermediate age group has an average K
D
=0.81, and the youngest group has K
D
=0.77. K
D
[Mg/Fe] for biotite/hornblende from the southern California batholith is 0.83, close to the average of the intermediate age group in the central Sierra Nevada. The calculated difference in pressure of crystallization between rocks of the Feather River area and the southern California batholith is 1 kb; the rocks of the Feather River area being crystallized at a higher pressure. This is in good agreement with the low-pressure contact metamorphism in the south (pyroxene hornfels facies), as compared with a medium-pressure metamorphism around the northern plutons, where andalusitesillimanite-cordierite and andalusite-staurolite subfacies of the amphibolite facies indicate pressures of about 4 kb.Trace elements Cr, V, Ni, Co, Ga are distributed equally between biotite and hornblende, whereas Ba and possibly Cu are concentrated in biotite and Sr and Sc and possibly Zr in hornblende.Publication authorized by the Director, U.S. Geological Survey. 相似文献
860.
A Palacomagnetic isochron dated at about 8.1 Myr BP and detailed lithostratigraph of a 40 m interval exposed along strike for 40 km establish the depositional patterns of two contemporaneous, interfingering fluvial systems in the upper part of the Meddle Siwalik sequence. The two systems, referred to as the buff and blue-grey, differ in unit shape, lithofacies, bedding sequence, palaeocurrent direction and sand composition. Interfingering occurs along the south-west-north-east strike of the outcrops, with the palaeodrainage directions of the two systems generally perpendicular to this line. The axis of the blue-grey system, which deposited widespread sheet sands and silts, lay toward the south west end of the study area. The more complex axis of the buff system, which deposited shoe-string sand bodies and lage volumes of silt and clay, lay toward the north-east. The source area for both systems was the rising Himalyan belt to the north and noth-east of the study area. At maximum extent the blue-grey system occupied a channel belt at least 25 km wide. Channel belt widths and depths for the buff system are 1–3 km and 3–7 m, respectively. Current directions averge 94° for blue-grey sands and 136° for buff sands. Blur-grey sands contain 20% more rock fragments and are otherwise less mature than buff sands. The buff system shows a verticla pattern of avulsion, palaeosol formation and floodplain aggradation which we attribute to autocyclic processes of parallel rivers. The blue-grey system shows phases of erosion accompaniced laterally by plaeosol formation, folowed by valley fill and overfowing of interfluve surfaces. Theis pattern may be caused by allocyclic presses affecting the source area. We interpret the blue-grey system as a major drainage from the interior Himalayas (perhaps the ancestral Indus) and the buff system as a complex of smaller drinages along the mountain front which were probably ributaries to the bluegrey syste. Vertebrate fossils including hominoid primates from the area are almost exclusively associated with lithofacies of the buff system, and this probably refects both taphonomic and palaeoecological differences between the two systems. 相似文献