Morphometric and molecular data on two mitochondrial genes of a newly discovered chimaeran fish (Hydrolagus melanophasma, Chondrichthyes)     

José De La Cruz-Agüero  Francisco Javier García-Rodríguez  Víctor Manuel Cota-Gómez  Felipe Neri Melo-Barrera  Rogelio González-Armas 《Ocean Science Journal》2012,47(2):147-153

Fresh and preserved (type material) specimens of the black ghost chimaera Hydrolagus melanophasma were compared for morphometric characteristics. A molecular comparison was also performed on two mitochondrial gene sequences (12S rRNA and 16S rRNA gene sequences). While significant differences in measurements were found, the differences were not attributable to sexual dimorphism or the quality of the specimens, but to the sample size and the type of statistical tests. The result of the genetic characterization showed that 12S rRNA and 16S rRNA genes represented robust molecular markers that characterized the species.  相似文献   

Industrial structural changes in Hong Kong, China under one country, two systems framework     

Simon Xiaobin ZHAO  Carola B RAMóN-BERJANO 《中国地理科学(英文版)》2012,22(3):302-318

Hong Kong has undergone substantial economic transformations and developed into a sophisticated business and financial center in the Asia-Pacific region,since the return of sovereignty to China as a Special Administrative Region under the One Country Two Systems (OCTS) in 1997.This paper discusses and analyzes the industrial structural changes of Hong Kong in recent decades as well as its future challenges and opportunities.The data and finding reveal that even though Hong Kong will face fierce competition from the Mainland’s cities as the rise of China,the important role as a bridge between China and the rest of the world will brace Hong Kong itself under the OCTS for developing into a service hub for business and trade in the Asia-Pacific region.  相似文献   

Landform instability and land-use dynamics in tropical high mountains, Central Mexico     

GARCíA-ROMERO Arturo  ACEVES-QUESADA José Fernando  ARREDONDO-LEóN Carlos 《山地科学学报》2012,9(3):414-430

This investigation is an analysis of the influence of landform instability on the distribution of land-use dynamics in a hydrographical basin, located in the Mexican Volcanic Belt mountain range (central Mexico), currently affected by substantial changes in land use and deforestation. A landform map was produced, in addition to seven attribute maps - altimetry, drainage density, slope, relief energy, potential erosion, geology and tectonics - which were considered as factors for determining landform instability through Multi-criteria Evaluation Analysis. Likewise, the direction and rhythm of land-use dynamics were analyzed in four dates - between 1976 and 2000 - and cross tabulations were made between them, in order to analyze the trends and processes of land-use dynamics. Afterwards, the databases obtained were cross tabulated with the landform variables to derive areas, percentages and correlation indices. In the study area, high-instability landforms are associated with most ancient volcanic and sedimentary landforms, where high altitude, drainage density, slope and potential to develop gravitational and fluvial processes are the major factors favouring a land-use pattern, dominated by the conservation of extensive forest land, abandonment of human land use and regeneration of disturbed areas. In contrast, low-instability landforms correspond to alluvial plains and lava hills covered by pyroclasts, where low potential erosion to develop fluvial processes, added to water and soil availability and accessibility, have favoured a land-use pattern dominated by the expansion of agroforestry plantations and human settlements, showing a marked trend towards either intensification or permanence of the current land use and with little abandonment and regeneration.  相似文献   

Gigantic low-gradient landslides in the northern periphery of the Crimean Mountains (Ukraine)     

Tom&#x; Pnek  Jan Hradecký  Veronika Smolkov  Karel &#x;ilhn 《Geomorphology》2008,95(3-4):449-473

Large-scale, low-gradient ancient landslides estimated at 5.4–18.9 km² in area and  0.2–1.2 km³ in volume have been studied in the northern hilly periphery of the Crimean Mountains (Ukraine). They originated on slopes along wide water gaps of rivers (Belbek, Kacha, Alma and Biyuk–Karasu) crossing the cuestas of the northern foothills. The slopes generally consist of slightly northward tilting Miocene (mainly Sarmatian) limestones overlying weak, clay-rich Lower Neogene–Palaeogene substratum with a significant content of smectite. Although the region is characterised by the least active contemporary morphodynamics within the Crimean Mountains, the landslides which were studied are of the same size or even larger than various types of landslides occupying active geomorphic domains of the highest mountain range in the southernmost part of the peninsula. The landslides are generally a spreading type, but the sliding mechanics were probably very complex, involving toppling, rotational slides, gravitational folding and translational block slides. All the landslides which were studied are located in the vicinity of regional faults and three of them have headscarps aligned along faults. A common feature is also a location close (within several km) to the Mesozoic suture zone which is the most important tectonic feature in the northern periphery of the Crimean Orogene. This suture was formerly classified as aseismic; however, evidence of strong, low-frequency palaeoearthquakes was collected during the last decade within both the Mesozoic suture and the low-lying northern part of the Crimean Peninsula. Radiocarbon dating of deposits associated with the landslides has revealed at least two phases of increased landslide-activity during the Late Glacial chronozone and Holocene epoch. The main landslide phase presumably took place at some time between the Late Glacial and Atlantic chronozones. Minor reactivation of landslide toes occurred during the Subatlantic chronozone and some of them have been active up to recent times. The first major landslide phase was possibly triggered by an earthquake, whereas late Holocene activity can be attributed both to seismic and hydroclimatic factors.  相似文献   

Seismic stratigraphy of Lago Puyehue (Chilean Lake District): new views on its deglacial and Holocene evolution     

François Charlet  Marc De Batist  Emmanuel Chapron  Sébastien Bertrand  Mario Pino  Roberto Urrutia 《Journal of Paleolimnology》2008,39(2):163-177

Prior to the collection of a series of sediment cores, a high- and very-high-resolution reflection seismic survey was carried out on Lago Puyehue, Lake District, South-Central Chile. The data reveal a complex bathymetry and basin structure, with three sub-basins separated by bathymetric ridges, bedrock islands and interconnected channels. The sedimentary infill reaches a thickness of >200 m. It can be sub-divided into five seismic-stratigraphic units, which are interpreted as: moraine, ice-contact or outwash deposits (Unit I), glacio-lacustrine sediments rapidly deposited in a proglacial or subglacial lake at the onset of deglaciation (Unit II), lacustrine fan deposits fed by sediment-laden meltwater streams in a proglacial lake (Unit III), distal deposits of fluvially derived sediment in an open, post-glacial lake (Unit IV) and authigenic lacustrine sediments, predominantly of biogenic origin, that accumulated in an open, post-glacial lake (Unit V). This facies succession is very similar to that observed in other glacial lakes, and minor differences are attributed to an overall higher depositional energy and higher terrigenous input caused by the strong seismic and volcanic activity in the region combined with heavy precipitation. A long sediment core (PU-II core) penetrates part of Unit V and its base is dated as 17,915 cal. yr. BP. Extrapolation of average sedimentation rates yields an age of ca. 24,750 cal. yr. BP for the base of Unit V, and of ca. 28,000 cal. yr. BP for the base of Unit IV or for the onset of open-water conditions. This is in contrast with previous glacial-history reconstructions based on terrestrial records, which date the complete deglaciation of the basin as ca. 14,600 cal. yr. BP. This discrepancy cannot be easily explained and highlights the need for more lacustrine records from this region. This is the second in a series of eight papers published in this special issue dedicated to the 17,900 year multi-proxy lacustrine record of Lago Puyehue, Chilean Lake District. The papers in this special issue were collected by M. De Batist, N. Fagel, M.-F. Loutre and E. Chapron.  相似文献   

Contribution of non-pollen palynomorphs to the paleolimnological study of a high-altitude Andean lake (Laguna Verde Alta,Venezuela)     

Valentí Rull  José A. López-Sáez  Teresa Vegas-Vilarrúbia 《Journal of Paleolimnology》2008,40(1):399-411

This paper evaluates the potential usefulness of non-pollen palynomorphs or NPPs (microfossils other than pollen and spores present in palynological preparations) contained in lake sediments in the paleolimnological reconstruction of high altitude environments (>4,000 m) from the Venezuelan Andes. A synthetic, quantitative approach is employed, instead of the classical analytical and mostly qualitative approach commonly used so far for NPPs. The main sources of variation are the Pediastrum–Botryococcus alternation and the relationship between these two algae and animal remains such as Acari legs, postabdomina of Cladocera, mandibles of other invertebrates, and an unknown type called LVA-1. Other significant microfossils are remains of Rivularia-type and turbellarian oocytes, including Gyratrix. The sequence initiates around 15,000 calibrated years before present (cal BP) with the deglaciation of the lake catchment, high water levels and still cold climates. A phase of lower lake levels was recorded between about 12,000 and 6,000 cal BP. Temperatures increased by around 9,000 and 7,000 cal BP, and then decreased until 6,000 cal BP. Since that time, both lake levels and temperature increased again and stabilized at about 4,000 cal BP, when they reach modern-like values. These results show a good agreement with previous studies based on pollen, diatom and oxygen isotope analyses, and provide additional paleoecological information, as for example the possibility of a previously unrecorded Younger Dryas signal. The inclusion of quantitative NPP analysis in routine paleolimnological studies using synthetic methods is thus recommended. Possible future improvements are suggested, mainly those related with the development and use of NPP modern analogs.  相似文献   

High variability in carbon and nitrogen isotopic discrimination of tropical freshwater invertebrates     

Ana Paula C. de Carvalho  Björn Gücker  Mario Brauns  Iola G. Boëchat 《Aquatic Sciences - Research Across Boundaries》2015,77(2):307-314

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Scale-dependent correlations between soil heavy metals and As around four coal-fired power plants of northern Greece     

Nikos Nanos  Theodoros Grigoratos  José Antonio Rodríguez Martín  Constantini Samara 《Stochastic Environmental Research and Risk Assessment (SERRA)》2015,29(6):1531-1543

We analyse the concentration of five trace elements (As, Cu, Ni, Pb and Zn) in the topsoil of the Kozani-Ptolemais basin where four coal-fired power plants run to provide almost 47.8 % of electricity requirements in Greece. We assume that if the power plants have altered the spatial (co)variation of the analysed elements through their toxic by-products, their effect would be observable only on a small spatial scale, since deposition of airborne pollutants is more evident if it is near the emission source. We used Factorial Cokriging to estimate the small-scale correlations among soil elements and to compare them to large spatial-scale correlations. Soil samples were collected from 92 sites. Given the low concentrations in soil heavy metals and As, we observed no serious soil contamination risk. We estimated correlations among the analysed elements on two spatial scales. On the larger scale, Ni and As exhibited higher correlation and received higher weights for the first regionalized factor, contrary to Cu, Pb and Zn which weighted more for the second regionalized factor. On the small spatial scale As associated with neither Ni nor other heavy metals. We conclude that soil arsenic has been altered by enrichment caused by some power plants through fly ash deposition and/or disposal. However, enrichment of soil elements was detectable only on the smaller spatial scale because anthropogenic inputs in soil through airborne emissions and subsequent deposition are evident only in the vicinity of the emission source.  相似文献   

Evaluation of the recorded ground motions for the unusual earthquake of 13 August 2006 (M w 5.3) in Michoacán México     

Alejandro Ramírez-Gaytán  Miguel A. Jaimes  William L. Bandy  Victor M. Huerfano  Ricardo A. Salido-Ruiz 《Journal of Seismology》2015,19(4):881-898

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Impact of heat and cold waves on circulatory-cause and respiratory-cause mortality in Spain: 1975–2008     

C. Linares  J. Diaz  A. Tobías  R. Carmona  I. J. Mirón 《Stochastic Environmental Research and Risk Assessment (SERRA)》2015,29(8):2037-2046

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