2,665 research outputs found

    Quantitative assessment of the spatial variability of morphological and physical properties of some alluvial soils at Lincoln College, Canterbury : A thesis submitted in partial fulfilment of the requirements for the degree of Master of Applied Science in the University of Canterbury [Lincoln College]

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    The complex soil distribution across part of a Lincoln College Farm relates to the previous history and pattern of alluvial deposition. Depth to mottles (DM), depth to gravels (DG), and thickness of loamy sand and/or coarser-textured layers (TS) are used to classify the soils and delineate the area into Eyre, Templeton and Wakanui soil-series simple mapping units. Geostatistical analyses of the grid data reveal that values of each morphological parameter are spatially dependent, though to different extents. Most variation of DM, for instance occurs between 30 m and 430 m, whereas a large amount of the variation in TS is present within less than 30 m. The morphological parameters also vary anisotropically, with the direction of maximum variation for DM and DG being NE-SW across a major abandoned channel hollow. Similar patterns are reflected in the soil maps of the study area and of adjacent larger regions, where mapping units are elongated in a NW-SE direction. Geostatistical methods are more efficient than conventional in determining optimal sampling strategies for future soil survey and variability studies: less samples are needed to achieve the same level of precision. The morphologically based soil classification system is generally effective in separating soils into (series) taxonomic units in terms of soil physical properties. Examined hydraulic properties [e.g. "field -saturated" hydraulic conductivity (Kfs) differ between typical profiles of each taxonomic unit : these observations are statistically substantiated by data from taxonomically-pure "window areas" of the three soil series. The differences are mainly attributable to spatial changes in soil texture and pore-size distributions. Different amounts of variation in physical properties, however, are still present within each taxonomic unit. The variation in physical properties amongst the combined window areas is reduced, though, to differing extents by the classification and delineation into separate taxonomic units. More than half of the variance in moisture content at both topsoil and subsoil depths amongst Templeton and Wakanui taxonomic units for instance is accounted for by the classification. and is thus clue to differences between the two soils. Little contribution however is made by the classification in reducing the heterogeneity of Kfs, in topsoils. The classification is particularly effective in separating Wakanui from Templeton taxonomic units in terms of subsoil Kfs an important property controlling water movement storage and related soil-forming processes

    Neurocalcin-delta: a potential memory-related factor in hippocampus of obese rats induced by high-fat diet.

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    Introduction: Aberrant protein expression within the hippocampus has recently been implicated in the pathogenesis of obesity- induced memory impairment.Objectives: The objective of the current study was to search for specific memory-related factors in the hippocampus in obese rats.Methods: Sprague-Dawley (SD) rats were fed either a high-fat (HF) diet or normal-fat (NF) diet for 10 weeks to obtain the control (CON), diet-induced obese rats (DIO) and diet-resistant (DR) rats. D-galactose was injected subcutaneously for 10 weeks to establish model (MOD) rats with learning and memory impairment. After the hippocampus of the rats sampling, the proteome analysis was conducted using two-dimensional get electrophoresis (2-DE) combined with peptide mass fingerprinting (PMF).Results: We found 15 differential proteins that expressed in the hippocampus in rats induced by HF diet from the 2-DE map. In addition, Neurocalcin-delta (NCALD) was nearly down-regulated in the DR rats compared with CON rats and MOD rats, which was further confirmed by Western blot, real-time PCR and ELISA results.Conclusion: Our data demonstrates that the differential memory-related proteins were a reflection of the HF diet, but not potential factors in obesity proneness or obesity resistance. Furthermore, NCALD is proved to be a potential hippocampus-memory related factor related to obesity.Keywords: Diet-induced obesity; diet-resistant; high fat diet; neurocalcin-delta; proteom

    Maize straw application as an interlayer improves organic carbon and total nitrogen concentrations in the soil profile: A four-year experiment in a saline soil

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    Soil salinization is a critical environmental issue restricting agricultural production. Deep return of straw to the soil as an interlayer (at 40 cm depth) has been a popular practice to alleviate salt stress. However, the legacy effects of straw added as an interlayer at different rates on soil organic carbon (SOC) and total nitrogen (TN) in saline soils still remain inconclusive. Therefore, a four-year (2015–2018) field experiment was conducted with four levels (i.e., 0, 6, 12 and 18 Mg ha–1) of straw returned as an interlayer. Compared with no straw interlayer (CK), straw addition increased SOC concentration by 14–32 and 11–57% in the 20–40 and 40–60 cm soil layers, respectively. The increases in soil TN concentration (8–22 and 6–34% in the 20–40 and 40–60 cm soil layers, respectively) were lower than that for SOC concentration, which led to increased soil C:N ratio in the 20–60 cm soil depth. Increases in SOC and TN concentrations in the 20–60 cm soil layer with straw addition led to a decrease in stratification ratios (0–20 cm:20–60 cm), which promoted uniform distributions of SOC and TN in the soil profile. Increases in SOC and TN concentrations were associated with soil salinity and moisture regulation and improved sunflower yield. Generally, compared with other treatments, the application of 12 Mg ha–1 straw had higher SOC, TN and C:N ratio, and lower soil stratification ratio in the 2015–2017 period. The results highlighted that legacy effects of straw application as an interlayer were maintained for at least four years, and demonstrated that deep soil straw application had a great potential for improving subsoil fertility in salt-affected soils.publishedVersio

    Mapping the distribution of Anthrax in Mainland China, 2005-2013

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    Anthrax in China was characterized by significant seasonality and spatial clustering. The spatial distribution of human anthrax was largely driven by livestock husbandry, human density, land cover, elevation, topsoil features and climate. Enhanced surveillance and intervention for livestock and human anthrax in the high-risk regions, particularly on the Qinghai-Tibetan Plateau, is the key to the prevention of human infections

    Influence of organic and mineral amendments on soil microbial properties and processes

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    Microbial diversity in soils is considered important for maintaining sustainability of agricultural production systems. However, the links between microbial diversity and ecosystem processes are not well understood. This study was designed to gain better understanding of the effects of short-term management practices on the microbial community and how changes in the microbial community affect key soil processes. The effects of different forms of nitrogen (N) on soil biology and N dynamics was determined in two soils with organic and conventional management histories that varied in soil microbial properties but had the same fertility. The soils were amended with equal amounts of N (100 kg ha−1) in organic (lupin, Lupinus angustifolius L.) and mineral form (urea), respectively. Over a 91-day period, microbial biomass C and N, dehydrogenase enzyme activity, community structure of pseudomondas (sensu stricto), actinomycetes and α proteobacteria (by denaturing gradient gel electrophoresis (DGGE) following PCR amplification of 16S rDNA fragments) and N mineralisation were measured. Lupin amendment resulted in a two- to five-fold increase in microbial biomass and enzyme activity, while these parameters did not differ significantly between the urea and control treatments. The PCR–DGGE analysis showed that the addition of mineral and organic compounds had an influence on the microbial community composition in the short term (up to 10 days) but the effects were not sustained over the 91-day incubation period. Microbial community structure was strongly influenced by the presence or lack of substrate, while the type of amendment (organic or mineral) had an effect on microbial biomass size and activity. These findings show that the addition of green manures improved soil biology by increasing microbial biomass and activity irrespective of management history, that no direct relationship existed among microbial structure, enzyme activity and N mineralisation, and that microbial community structure (by PCR–DGGE) was more strongly influenced by inherent soil and environmental factors than by short-term management practices

    Synergistic anti-atherosclerotic effect of Yerba Maté (Illex Paraguariensis) polyphenols and Lox-1 silencing in foam cell model

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    Purpose: To elucidate the anti-atherosclerotic effect of Yerba Mate polyphenols (MP) as well as the anti-atherosclerotic effect of a combination of MP and silencing of lectin-like oxidized low-density lipoprotein receptor-1 interference group (LOX)-1.Methods: The anti-atherosclerotic effects of control group (CG), simvastatin group (SG), MP group (MP), LOX-1 interference group (LOX) and MP + LOX-1 interference group (MP-LOX) were determined using Oil Red O staining, enzyme-linked immunosorbent assay (ELISA) and Western blot assay.Results: The levels of foam cells, intracellular lipids, viz, total cholesterol (TC), free cholesterol (FC), cholesterol ester (CE) and acyl-coenzyme A: cholesterol acyltransferase 1 (ACAT1); LOX-1, inflammation (TNF-alpha, IL-6 and pNF-κB/NF-κB); adhesion molecular status (ICAM-1 and VCAM-1), and monocyte chemotactic protein-1 in SG and in MP, LOX and MP-LOX groups were significantly decreased, when compared with CG (p < 0.01). The levels of these parameters were much lower in MPLOX group than in SG (p < 0.01). However, they were synergistically reduced in MP-LOX group, relative to MP group or LOX group (p < 0.01). Combination of LOX-1 gene silencing with MP produced synergistic anti-atherosclerotic effect which was reflected in decreases in foam cell formation, intracellular lipids, inflammatory status, adhesion molecular status, and MCP-1-mediated migration and infiltration of macrophages in foam cells.Conclusion: The synergistic anti-atherosclerotic effects of MP and LOX-1 gene silencing may be potential tools for development of anti-atherosclerotic agents

    Effects of past and current management practices on crop yield and nitrogen leaching - a comparison of organic and conventional cropping systems

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    Farming practices can have significant effects on important soil processes, including nitrogen (N) dynamics and nitrate leaching. A lysimeter experiment was conducted to determine differences in N leaching resulting from past and current crop management practices. Intact monolith lysimeters (50 cm diam. × 70 cm deep) were taken from sites of the same soil type that had either been under long-term organic or conventional crop management. These were then managed according to established organic and conventional practices over 2 1/2 years using the same crop rotation (barley (Hordeum vulgare L.), maize (Zea mays L.), rape (Brassica napus L. ssp. oleifera) plus a lupin green manure (Lupinus angustifolius L.)) and two fertiliser regimes, resulting in four treatments based on soil management history and current fertilisation strategy. Dry matter yield of each crop was determined after harvest and leachates were collected after significant rainfall events and analysed for total mineral N concentrations. Mineral fertilisation had a clear positive effect on yields of the first crop, whereas there were no considerable differences between treatments for the last crop owing to a significant positive effect of green manure incorporation on yields. Although there was a trend of lower mineral N leaching from organically fertilised soils (organic management: 24.2 kg N ha–1; conventional management: 28.6), differences in N losses were not statistically significant between treatments. This shows that under the experimental conditions, leaching losses and crop yields were more strongly influenced by crop rotation and green manuring than by the presence or absence of mineral fertilisation. Overall, the study highlights the benefits of including a green manure in the crop rotation of any farming system

    Probing Primordial Gravitational Waves: Ali CMB Polarization Telescope

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    In this paper, we will give a general introduction to the project of Ali CMB Polarization Telescope (AliCPT), which is a Sino-US joint project led by the Institute of High Energy Physics (IHEP) and has involved many different institutes in China. It is the first ground-based Cosmic Microwave Background (CMB) polarization experiment in China and an integral part of China's Gravitational Waves Program. The main scientific goal of AliCPT project is to probe the primordial gravitational waves (PGWs) originated from the very early Universe. The AliCPT project includes two stages. The first stage referred to as AliCPT-1, is to build a telescope in the Ali region of Tibet with an altitude of 5,250 meters. Once completed, it will be the worldwide highest ground-based CMB observatory and open a new window for probing PGWs in northern hemisphere. AliCPT-1 telescope is designed to have about 7,000 TES detectors at 90GHz and 150GHz. The second stage is to have a more sensitive telescope (AliCPT-2) with the number of detectors more than 20,000. Our simulations show that AliCPT will improve the current constraint on the tensor-to-scalar ratio rr by one order of magnitude with 3 years' observation. Besides the PGWs, the AliCPT will also enable a precise measurement on the CMB rotation angle and provide a precise test on the CPT symmetry. We show 3 years' observation will improve the current limit by two order of magnitude.Comment: 11 pages, 7 figures, 2 table
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