Comments are presented on the article by Abbasnejad et al. (Environ Earth Sci 75:1306, 2016) dealing with qanat and hazards in Iran. My rebuttal starts from the direct attribution of the described hazards to qanat and addresses the importance in the correct use of terminology for geological hazards. All of the problems pointed out in Iran (subsidence, sinkholes, pollution) have, to me, an anthropogenic origin and cannot be directly ascribed to qanat. Eventually, I present some additional elements to highlight the remarkable importance of qanat systems and their influence on the development of similar underground structures in many countries of the Mediterranean Basin. This remarks the relevance of qanat as cultural heritage sites and the need for their preservation and valorization. 相似文献
International Journal of Earth Sciences - The Juchatengo complex (JC) suite is located between the Proterozoic Oaxacan complex to the north and the Xolapa complex to the south, and was amalgamated... 相似文献
The effects of the freshwater discharge of the Oued Sebou River on the macroinfauna, was studied on the sandy beach of Mehdia through the analysis of the abiotic parameters and of the macrozoobenthos. In autumn 2002 and spring 2003, three beach sites, each with two transects, localized at 50, 3500 and 5720 m from the river mouth respectively, were studied. Positive correlations were recorded for beach slope and pH whereas negative ones were obtained for organic matter content and salinity at increasing distances from the river mouth. Significant differences between beach sites and seasons occurred for median grain size, organic matter content and pH. For each beach site, mean macroinfauna abundance varied between 30 and 100 ind.·m−2 and in spring there was a significant correlation between this parameter and the increasing distance from the river mouth. No significant correlation was instead found between species richness and the increasing distance, although the farthest beach site from the mouth had the highest number of species during both seasons. The results indicated the importance of organic matter content and salinity for the macrofaunal abundance whereas the diversity indices were more affected by beach slope and grain size. The results showed that there was no clear spatial trend in compound indices of the macrofauna across the sampled sites and the influence of the river discharge of Sebou River did not seem to be significant and consistent on the macrobenthos of this mesotidal shore. Comparison with microtidal shores revealed the influence of the tidal excursion and swell characteristics on the response of the benthic structures of sandy beaches to discharges of freshwater. 相似文献
Over the last few years, the impacts of wildlife on agriculture have constantly been growing, in particular in areas close to woodland and in hunting ban zones (“refuge effect”). Public administrations have difficulty in meeting the growing requests for crop damage compensation. The development of appropriate measures to control this trend—starting from the understanding of the dynamics concerned—is crucial. The aim of this study was, therefore, to analyze damage at regional scale and define common local actions. In particular, the study involved different steps that define a spatial-based classification of risk levels, integrating statistical methods (principal component analysis and receiver operating characteristic) with multi-criteria evaluation (MCE) in a geographic information system (GIS). It turns out that, in the study area, the very high-risk zones affect 8.83% of used agricultural areas; about 97% of them concentrated in the first 400 m from the most suitable habitats. A selected cluster of 11 test areas within these zones allowed us to assess the cost-effectiveness of integrated prevention and control actions (IPCA) with respect to the compensation of the damage. The analysis shows cost of IPCA to be nearly twice the actual cost incurred by the public administration to compensate partially the damage. The comparison with the estimated damage shows the overall economic convenience of the proposed investment with significant differences depending on the areas. Thus, we suggest reaching an “agro-ecological” balance starting from actions on specific areas; if they produce the desired effects, they could be progressively extended to other areas with gradual investments (adaptive management).
The DArk Matter Particle Explorer(DAMPE),also known as Wukong in China,which was launched on 2015 December 17,is a new high energy cosmic ray and γ-ray satellite-borne observatory.One of the main scientific goals of DAMPE is to observe Ge V-Te V high energy γ-rays with accurate energy,angular and time resolution,to indirectly search for dark matter particles and for the study of high energy astrophysics. Due to the comparatively higher fluxes of charged cosmic rays with respect to γ-rays,it is challenging to identify γ-rays with sufficiently high efficiency,minimizing the amount of charged cosmic ray contamination. In this work we present a method to identify γ-rays in DAMPE data based on Monte Carlo simulations,using the powerful electromagnetic/hadronic shower discrimination provided by the calorimeter and the veto detection of charged particles provided by the plastic scintillation detector. Monte Carlo simulations show that after this selection the number of electrons and protons that contaminate the selected γ-ray events at~10 Ge V amounts to less than 1% of the selected sample.Finally,we use flight data to verify the effectiveness of the method by highlighting known γ-ray sources in the sky and by reconstructing preliminary light curves of the Geminga pulsar. 相似文献
Mineral inventories of enstatite chondrites; (EH and EL) are strictly dictated by combined parameters mainly very low dual oxygen (fO2) and sulfur (fS2) fugacities. They are best preserved in the Almahata Sitta MS‐17, MS‐177 fragments, and the ALHA 77295 and MAC 88136 Antarctic meteorites. These conditions induce a stark change of the geochemical behavior of nominally lithophile elements to chalcophile or even siderophile and changes in the elemental partitioning thus leading to formation of unusual mineral assemblages with high abundance of exotic sulfide species and enrichment in the metallic alloys, for example, silicides and phosphides. Origin and mode of formation of these exotic chondrites, and their parental source regions could be best scrutinized by multitask research experiments of the most primitive members covering mineralogical, petrological, cosmochemical, and indispensably short‐lived isotopic chronology. The magnitude of temperature and pressure prevailed during their formation in their source regions could eventually be reasonably estimated: pre‐ and postaccretionary could eventually be deduced. The dual low fugacities are regulated by the carbon to oxygen ratios estimated to be >0.83 and <1.03. These parameters not only induce unusual geochemical behavior of the elements inverting many nominally lithophile elements to chalcophile or even siderophile or anthracophile. Structure and mineral inventories in EL3 and EH3 chondrites are fundamentally different. Yet EH3 and EL3 members store crucial information relevant to eventual source regions and importantly possible variation in C/O ratio in the course of their evolution. EL3 and EH3 chondrites contain trichotomous lithologies (1) chondrules and their fragments, (2) polygonal enstatite‐dominated objects, and (3) multiphase metal‐rich nodules. Mineralogical and cosmochemical inventories of lithologies in the same EL3 indicate not only similarities (REE inventory and anomalies in oldhamite) but also distinct differences (sinoite‐enstatite‐graphite relationship). Oldhamite in chondrules and polygonal fragments in EL3 depict negative Eu anomaly attesting a common cosmochemical source. Metal‐dominated nodules in both EL3 and EH3 are conglomerates of metal clasts and sulfide fragments in EH3 and concentrically zoned C‐bearing metal micropebbles (≥25 μm ≤50 μm) in EL3 thus manifesting a frozen in unique primordial accretionary metal texture and composition. Sinoite‐enstatite‐diopside‐graphite textures reveal a nucleation and growth strongly suggestive of fluctuating C/O ratio during their nucleation and growth in the source regions. Mineral inventories, sulfide phase relations, sinoite‐enstatite‐graphite intergrowth, carbon and nitrogen isotopic compositions of graphite, spatial nitrogen abundance in graphite in metal nodules, and last but not least 129I/129Xe and 53Mn/53Cr systematics negate any previously suggested melting episode, pre‐accretionary or dynamic, in parental asteroids. 相似文献
Two sedimentary units are recognized by means of stratigraphic and sedimentological analyses at Monte Verde, a late Pleistocene archeological site with stone tools and well-preserved wood artifacts and botanical remains, that lies southwest of Lago Llanquihue and north of the Golfo de Reloncavi in the southern end of the Chilean Central graben. the geological evidence shows that at no time after 33,000 yr B.P., and perhaps since the first Llanquihue advance (before 56,000 yr B.P.), was the Monte Verde area covered by ice. Influences of two glacial advances at 20,000 and 15,000-14,500 yr B.P. are recognized at the site; effects of the Varas Interstade, however, are not identified. Rapid climatic change took place after the end of the Llanquihue Glaciation. It was shortly interrupted by a cool, wet period around 10,000 yr B.P., after which a well-documented Hypsithermal (8270-4750 yr B.P.) accompanied by pyroclastic vulcanism followed. The evidence indicates that around 13,000 yr B.P. 1) the site occupants settled on the sandy point bars and beaches of the old creek channel and 2) the area was habitated during cool and wet conditions similar to those that prevail in the area today. Evidence for reconstruction of the paleo-environment and climate of the terminal Pleistocene and the preliminary implications of these findings for understanding the human occupation at Monte Verde are discussed. 相似文献