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1.
Jeffrey E. Moore Bryan P. Wallace Rebecca L. Lewison Ramúnas Žydelis Tara M. Cox Larry B. Crowder 《Marine Policy》2009
This paper reviews the available information (observer programs, estimates, statutes, regulations) for bycatch of marine mammals, sea turtles, and seabirds in fisheries of the United States. Goals of the review were to evaluate the state of knowledge of bycatch and the role of existing protective legislation in shaping bycatch management for different taxa. Pressing issues are identified, as well as knowledge gaps and policy limitations that hinder multi-species bycatch reduction. The USA has made important progress toward reducing bycatch in its fisheries, but the efficacy of its management has been limited somewhat by a focus on taxon- and fishery-specific regulation and the lack of consistent mandate across taxa for taking a cumulative perspective on bycatch. Applying consistent criteria across taxa for setting bycatch limits (e.g., extending the approach used for marine mammals to sea turtles and seabirds) would be the first step in a multi-species approach to bycatch reduction. A population-based multi-species multi-gear approach to bycatch would help identify priority areas where resources are needed most and can be used most effectively. 相似文献
2.
Bandwidth effects in the GAIA photometric system 3G are discussed. It is demonstrated that careful account for the bandwidth
effects in any proposed GAIA photometric system has to be made, in order to determine the fundamental parameters of heavily
reddened stars.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
3.
We investigate the plausibility of using diffuse interstellar band at862 nm for tracing interstellar extinction with the ESA's
astrometric space mission GAIA. For this purpose we perform numerical tests to simulate the conditions of real observations,
covering a wide range of stellar parameters and different amounts of interstellar extinction. Our simulations indicate that
with the present Radial Velocity Spectrometer setup the uncertainty in color excess of σE(B-V)≤ 0.05 can be achieved only for the interstellar reddening tracers brighter than V ∼ 13. None of the plausible tracers can provide accurate color excesses (σ
E(B-V)
≤ 0.05) at the distances beyond 2 kpc. We therefore conclude that with the currently planned instrumentation onboard GAIA
this method can not be used as a stand-alone approach for probing interstellar extinction on the Galactic distance scales
within the framework of the GAIA mission.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
4.
5.
GIS-based land suitability analysis integrating multi-criteria evaluation for the allocation of potential pollution sources 总被引：2，自引：1，他引：1
The geological environment has been heavily polluted by chemical substances over the past few decades. Pollution sources located on the earth’s surface or underground have affected the quality of the environment. A significant amount of impact could be reduced if the allocation of potential pollution sources was based on an evaluation of environmental conditions. The main objective of this study was to develop a methodology for the allocation of potential pollution sources by employing GIS and multi-criteria evaluation techniques. This methodology was applied to a study area located in the eastern part of Lithuania. A GIS-based land suitability analysis was performed after identifying 16 factors concerning the geological and socio-economic environment, which were important for environmental protection, land use and spatial planning. The environmental and socio-economic factors were divided into eliminating and limiting criteria. Criteria maps based on the selected factors were compiled. Areas delineated by eliminating criteria were identified as unsuitable for development (according to national legislation). Limiting criteria were evaluated according to the suitability level, which were determined in this study considering the principles of sustainable development. The relative importance of each criterion was assessed utilising the Analytical Hierarchy Process (AHP). A land suitability index (LSI) was calculated and the final result of the land suitability analysis was summarized in three suitability maps (environmental, socio-economic and composite). Four suitability classes (unsuitable, least, moderately and most suitable) for the allocation of potential pollution sources in the study area were used, and the nine most suitable candidate sites were selected according to the proposed methodology. 相似文献
6.
While consideration of natural environment factors increased in the late eighties, from the very beginning geoscience was outside the planning process. It was a consequence of the state of applied geology in Lithuania. During this time the development of certain industrial projects was stopped; urgent environment protection measures came into use; it was recognised that nonrational utilization depleted resources. 相似文献
7.
Arūnas Kučinskas Vladas Vansevičius Toshihiko Tanabé 《Astrophysics and Space Science》2002,280(1-2):151-157
We discuss a possible use of the asymptotic giant branch (AGB) stars for tracing star formation histories on the Galactic
and extragalactic distance scales with the ESA's astrometric space mission GAIA. Extensive numerical simulations demonstrate
that metallicities (Δ [M/H] ≲ 0.3) can be obtained for the AGB stars with GAIA up to the distances of ∼ 200 kpc, if no interstellar
extinction is present. Reliable population ages can be also obtained from the AGB stars if their T
eff are constrained precisely. We show that precise effective temperatures can be obtained by fitting observed spectral energy
distributions of the AGB stars with theoretical fluxes calculated from the synthetic spectra. A combination of the derived
effective temperatures with the bolometric luminosities allows to derive precise population ages for a wide range of ages
and metallicities over the large distance scales. This demonstrates that AGB stars can be employed very effectively for tracing
star formation histories with GAIA, allowing to refine the global evolutionary scenarios of stellar populations in the Milky
Way and the galaxies beyond.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
8.
Jokūbas Sūdžius Saulius Raudeliūnas Arūnas Kučinskas Audrius Bridžius Vladas Vansevičius 《Astrophysics and Space Science》2002,280(1-2):109-114
We investigate the possibilities for tracing interstellar extinction with the ESA's astrometric space mission GAIA. The analysis
is based on detailed simulations of the GAIA photometry, which are used to derive the distribution of interstellar matter
in a modelled Galaxy. We find that `small' diffuse clouds (diameter D = 4 pc, E
B-V = 0.06) will be easily traced with GAIA up to the distances of ∼ 800 pc. `Large' diffuse interstellar clouds (D = 10 pc, E
B-V = 0.13) will be located up to the distances of ∼ 2.5 kpc. This holds for the reddening tracers of spectral types O – K2 brighter
than V = 17. Inmost cases, due to their low spatial density, the early type stars (O– A2) cannot provide reliable information about
the distribution of interstellar matter. None of the reddening tracers measured by GAIA will provide reliable identification
of the individual interstellar clouds beyond the distances of ∼ 3 kpc. Therefore, we conclude that the information available
from photometric observations will be not sufficient for the detailed reconstruction of the 3-D distribution of Galactic interstellar
matter. It is therefore extremely important to define the new strategies which would allow to combine all the available information,
including the earlier space- and/or ground-based investigations, together with the information which will be provided by GAIA
itself (parallaxes, E
B-V etc.).
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
9.
The Proterozoic pre-Ediacaran metamorphic basement of the southern Tajik (North Afghanistan) continental block and the adjacent Band-e-Bayan zone is exposed in the Ghor Province of Central Afghanistan. It is predominantly composed of the EW-striking supracrustal succession consisting of interbedded felsic schists and gneisses (metapsammites), amphibolites (metabasalts), calcite and dolomite marbles. The metamorphic facies changes from greenschist in the Band-e-Bayan zone to amphibolite facies in the Tajik block. The supracrustal rocks of the Band-e-Bayan zone and Tajik block possess common features suggesting that the former represents a tectonized part of the latter. The geochemical characteristics of metapsammites indicate derivation of the clastic material from a continental arc and, partly from a passive continental margin, whereas the composition of metabasalts suggests their possible formation in a continental rift basin. The tectonic setting of supracrustal unit could be interpreted as a back-arc type basin. We presume that the Tajik microcontinent split off the Gondwana supercontinent along an ancient rift zone during the late Paleozoic. 相似文献
10.
Diana Meilutytė-Lukauskienė Vytautas Akstinas Jūratė Kriaučiūnienė Diana Šarauskienė Aldona Jurgelėnaitė 《Acta Geophysica》2017,65(1):89-102
In this research, variability of spring (from 1 March to 30 May) and flash (from 1 June to 30 November) floods in rivers of different regions was analysed. The territory of Lithuania is divided into three regions according to hydrological regime of the rivers: Western, Central, and Southeastern. The maximum river discharge data of spring and flash floods [a total of 31 water gauging stations (WGS)] were analysed. Comparison of the data of four periods (1922–2013, 1941–2013, 1961–2013, and 1991–2013) with the data of the reference period (1961–1990) was performed. Analysis included the longest discharge data set of the Nemunas River at Smalininkai WGS (1812–2013) as well. Mixed patterns of flood changes in Lithuanian rivers were detected. The analysis of flood discharges of the Nemunas River indicated that both spring and flash floods in Lithuania were getting smaller. 相似文献