340 research outputs found

    A Review on the Little Ice Age and Factors to Glacier Changes in the Tian Shan, Central Asia

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    Mountain glaciers are a reliable and unequivocal indicator of climate change due to their sensitive response to changes in temperature and precipitation. The importance of mountain glaciers is best reflected in regions with limited precipitation, such as arid and semi-arid central Asia. High concentration of glaciers and meltwater from the Tian Shan contribute considerably to the freshwater resource in Xinjiang (China), Kyrgyzstan and nearby countries. Documenting glacier distribution and research on glacier changes can provide insights and scientific support for water management in central Asia. As the most recent glacial event, the Little Ice Age (LIA, approximately AD 1300–1850) signifies the cold periods prior to the warming trend in the twentieth century. Here we present an overview of topics recently studied on the modern and LIA glaciers in the Tian Shan of the central Asia. With data sets of the Glacier Inventory of China and the presumed LIA glacial extents, we applied statistical models in a case study of the eastern Tian Shan to examine the impact of local topographic and geometric factors on glacier area changes. The findings of glacier size and elevation as key local factors are representative and consistent with other studies

    Landslide Inventory (2001–2017) of Chittagong Hilly Areas, Bangladesh

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    Landslides are a frequent natural hazard in Chittagong Hilly Areas (CHA), Bangladesh, which causes the loss of lives and damage to the economy. Despite this, an official landslide inventory is still lacking in this area. In this paper, we present a landslide inventory of this area prepared using the visual interpretation of Google Earth images (Google Earth Mapping), field mapping, and a literature search. We mapped 730 landslides that occurred from January 2001 to March 2017. Different landslide attributes including type, size, distribution, state, water content, and triggers are presented in the dataset. In this area, slide and flow were the two dominant types of landslides. Out of the five districts (Bandarban, Chittagong, Cox’s Bazar, Khagrachari, and Rangamati), most (55%) of the landslides occurred in the Chittagong and Rangamati districts. About 45% of the landslides were small (<100 m2) in size, while the maximum size of the detected landslides was 85202 m2. This dataset will help to understand the characteristics of landslides in CHA and provide useful guidance for policy implementation

    An Empirical Study of Consumers Emotional Reaction on Brand Collaboration

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    The study aims to examine customers’ emotional reaction to brand collaboration, taking into consideration the possible combination of different brand equities using three experiments. Mobile phone is selected as the hypothetical product. Samsung is selected as the brand with the highest awareness in the mobile manufacture category whereas Burberry is selected as the brand with the highest awareness in the fashion category. Meanwhile, HTC and Bottega Veneta have the lowest brand awareness in the mobile and fashion category respectively. Four companies were selected to launch a hypothetical collaboration product. Analyzing the experiment samples’ data from China mobile phone market, the study findings revealed that consumer’s image congruence level (brand attitude/ brand relationship) of a product having two high brand awareness (High-High) is significantly greater than consumer’s image congruence for the same product having two different brand awareness (High-Low or Low-High). Consumer’s image congruence level (brand attitude/ brand relationship) for a product with two high brand awareness (High-High) is significantly greater than consumer’s image congruence for the same product with two low brand awareness (Low-Low) brands. A psychological framework is proposed in order to give marketers a new analytical tool in understanding and implementing effective brand collaboration

    Peak-off-peak load shifting:Are public willing to accept the peak and off-peak time of use electricity price?

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    Encouraging residential electricity consumers switch from the flat-rate electricity tariff to the peak and off-peak pricing is an important task for demand response management. But are consumers willing to accept the peak and off-peak pricing?-This paper presents the results of a national survey with a sample size of 3863 residential electricity consumers throughout China. The result reveals that nearly two-third of the residential electricity consumers are willing to accept the peak and off-peak pricing. Consumer knowledge is the key driver for consumer acceptance. In addition, the influences of households’ electricity consumption and consumers’ socio-economic background profiles on consumer acceptance were also examined. Four barriers to consumer acceptance were identified. Among which, lack of the economic benefit is the primary hurdle. Finally, the managerial implications of this research are discussed.</p

    LiDAR-based Sinkhole Detection and Mapping in Knox County, Tennessee

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    Sinkholes are one of the major causes of damage to roads, buildings, and other infrastructure throughout the US. Sinkholes near or on roads are especially costly and occasionally deadly. Knox County and much of East Tennessee are located within karst areas (comprised of porous and soluble limestone and dolomite), deeming it at risk for sinkholes. Currently, Knox County uses contour maps to manually identify sinkholes. Supported by a geographic information system (GIS), we developed a streamlined model to identify the locations and extents of potential sinkholes using 1.3-ft resolution LiDAR (Light Detection and Ranging) data and applied it to the Dutchtown area of Knox County. This model consists of creating a Digital Elevation Model (DEM), filling the depressions in the DEM, extracting the depressions with a DEM difference, converting the depressions to a polygon shapefile, and analyzing the shape characteristics of the depressions. This work provides a pilot study for Knox County Stormwater Management in identifying potential sinkholes and has the potential to be used in other similar regions

    Assessing the Impact of a Geospatial Data Collection App on Student Engagement in Environmental Education

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    A critical component of environmental education is to ensure student understanding and use of available technologies to better experience and analyze spatially distributed features of the environment. Combining mobile technologies with geographic information systems in field data collection may provide a unique opportunity for students to feel engaged in what they are learning and take ownership of their learning process. We customized an open access data collection application using Collector for ArcGIS and investigated its impacts on student engagement and perception of the incorporation of technology within an environmental science curriculum. Analyses of pre- and post-surveys indicate that the inclusion of geospatial technologies as a part of environmental curricula allows students to take the lead on their own research, view field data interactively as opposed to looking at a database in hindsight and analyze multiscale data as it is presented during field data collection. The findings of this study are consistent with previous studies, suggesting a strong association between the inclusion of geospatial technologies as a part of curricula and student engagement

    Why magnesium isotope fractionation is absent from basaltic melts under thermal gradients in natural settings

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    Laboratory experiments have shown that thermal gradients in silicate melts can lead to isotopic fractionation; this is known as the Richter effect. However, it is perplexing that the Richter effect has not been documented in natural samples as thermal gradients commonly exist within natural igneous systems. To resolve this discrepancy, theoretical analysis and calculations were undertaken. We found that the Richter effect, commonly seen in experiments with wholly molten silicates, cannot be applied to natural systems because natural igneous samples are more likely to be formed out of partially molten magma and the presence of minerals adds complexity to the behaviour of the isotope. In this study, we consider two related diffusion-rate kinetic isotope effects that originate from chemical diffusion, which are absent from experiments with wholly molten samples. We performed detailed calculations for magnesium isotopes, and the results indicated that the Richter effect for magnesium isotopes is buffered by kinetic isotope effects and the total value of magnesium isotope fractionation can be zero or even undetectable. Our study provides a new understanding of isotopic behaviour during the processes of cooling and solidification in natural magmatic systems

    Optimization of extraction process and structural characterization of polysaccharides from Cornus officinalis

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    Objective: This study aimed to optimize the microwave assisted aqueous two-phase extraction (MATPE) process of polysaccharides from Cornus officinalis and obtain a uniform polysaccharide fraction. Methods: The best extraction technology was determined through an orthogonal experiment. To obtain a uniform polysaccharides fraction (COP-2-S), the crude extract of C. officinalis polysaccharides was purified using DEAE-52 cellulose and Sephadex G-100 column chromatography. The molecular weight of COP-2-S was determined by high performance gel permeation chromatography. The monosaccharide composition of COP-2-S was determined by gas chromatography. The structure of COP-2-S was characterized by UV, and IR spectra, and a scanning electron microscope. Results: The optimal MATPE process of polysaccharides from C. officinalis was as follows: microwave power of 300 W, ethanol volume fraction of 35%, ammonium sulfate mass fraction of 22%, a solid-to-liquid ratio of 1∶20 (g/mL), and the yield of polysaccharides from C. officinalis was (12.04±0.17)%. The molecular weight of COP-2-S was 17 450 Da. The molar ratio of arabinose, glucose, and galactose that made up the monosaccharide was 12.85∶30.71∶18.09. Conclusion: COP-2-S had no characteristic absorption at 260 nm and 280 nm. Besides, COP-2-S had typical infrared absorption characteristics of polysaccharides

    MODIS-Derived Spatiotemporal Changes of Major Lake Surface Areas in Arid Xinjiang, China, 2000–2014

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    Inland water bodies, which are critical freshwater resources for arid and semi-arid areas, are very sensitive to climate change and human disturbance. In this paper, we derived a time series of major lake surface areas across Xinjiang Uygur Autonomous Region (XUAR), China, based on an eight-day MODIS time series in 500 m resolution from 2000 to 2014. A classification approach based on water index and dynamic threshold selection was first developed to accommodate varied spectral features of water pixels at different temporal steps. The overall classification accuracy for a MODIS-derived water body is 97% compared to a water body derived using Landsat imagery. Then, monthly composites of water bodies were derived for the months of April, July, and September to identify seasonal patterns and inter-annual dynamics of 10 major lakes (\u3e100 km2) in XUAR. Our results indicate that the changing trends of surface area of major lakes varied across the region. The surface areas of the Ebinur and Bosten Lakes showed a significant shrinking trend. The Ulungur-Jili Lake remained relatively stable during the entire period. For mountain lakes, the Barkol Lake showed a decreasing trend in April and July, but the Sayram Lake showed a significant expanding trend in September. The four plateau lakes exhibited significant expanding trends in all three seasons except for Arkatag Lake in July. The shrinking of major lakes reflects severe anthropogenic impacts due to agricultural and industrial needs, in addition to the impact of climate change. The pattern of lake changes across the XUAR can provide insight into the impact of climate change and human activities on regional water resources in this arid and semi-arid region

    ACME2: an extended toolbox for automated cirque metrics extraction

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    With the availability of improved digital elevation models (DEMs) of global coverage, the morphological analysis of large populations of glacial cirques is possible, and can be used to derive important paleo-climate and environmental information related to the distribution and history of former glaciers. In 2017, an ArcGIS toolbox, ACME (Automated Cirque Metrics Extraction), was developed to derive 16 cirque metrics based on input cirque outlines, threshold midpoints, and DEMs. ACME has been widely used in cirque morphological analysis and regional comparisons. This paper presents a revised and extended toolbox, ACME2. This extended toolbox includes new functions to automatically derive cirque threshold midpoints (cirque foci) and 49 morphometric and locational variables, with attributes related to cirque location, size, shape, altitude, slope, and aspect, including variables related to the median axis, as well as 3 input metadata attributes. ACME2 also improves the methods for calculation of the hypsometric maximum and integral, and implements a new method for plan closure to be more consistent with the original definition. All ACME2 tools are coded in Python and can be imported into ArcGIS with user-friendly interfaces. Comparisons for 155 cirques in the English Lake District and 51 in the Shulaps Range, British Columbia, indicate consistency between the ACME2-derived and manually derived metrics, with most correlations r > 0.90: none <0.70. ACME2 provides more cirque metrics and automates the whole calculation sequence with cirque outlines and DEMs. Its comprehensive approach facilitates understanding of cirque form and development in all its variety
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