33 research outputs found

    Seasonal Variations in Voluntary Intake and Apparent Digestibility of Forages in Goats Grazing on Introduced Pasture

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    The nutrient composition of pasture, voluntary intake and digestibility of diet ingested by goats grazing on an introduced Leymus chinensis pasture were measured across spring (May), summer (July), autumn (October) and winter (March). In each season, 12 Inner Mongolian Cashmere goats (6 wethers and 6 does with an average live weight of 22.2±1.3 kg and 19.5±0.8 kg, respectively) were used to graze on a 2 hectares size paddock. Diet selection was observed and the plant parts selected by grazing goats and whole plant L. chinensis were sampled simultaneously. The alkane pair C32:C33 and C36 were used to estimate intake and digestibility, respectively. The results showed that the plant parts selected by goats had higher crude protein (CP) and lower acid detergent fiber (ADF) and neutral detergent fiber (NDF) than the whole plant, especially in the autumn and winter. The voluntary intake of dry matter (DM), CP, ADF, NDF, and metabolizable energy (ME) by goats was highest in summer (p<0.05). The goats ingested more CP, ME, and less ADF in spring than in autumn (p<0.05). The intakes of DM, CP, and ME were lowest in winter (p<0.05). There were significant differences in nutrient intake between wethers and does in each season, except for the ADF and ME intake per metabolic weight (LW0.75). The nutrient digestibilities were higher in spring and summer, and decreased significantly during the autumn and winter (p<0.05). Goats, especially wethers, had a relative constant NDF digestibility across seasons, however, the apparent digestibility of CP in both wethers and does, decreased to negative values in winter. The grazing goats experienced relatively sufficient nutrients supply in spring and summer, and a severe deficiency of CP and ME in winter

    Preparation and enhanced properties of Fe3O4 nanoparticles reinforced polyimide nanocomposites

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    Polyimide (PI) nanocomposite reinforced with Fe3O4 nanoparticles (NPs) at various NPs loadings levels of 5.0, 10.0, 15.0, and 20.0 wt% were prepared. The chemical interactions of the Fe3O4 NPs/PI nanocomposites were characterized using Fourier Transform Infrared (FT-IR) spectroscopy. X-ray Diffraction (XRD) results revealed that the addition of NPs had a significant effect on the crystallization of PI. Scanning electron microscope (SEM) and the atomic force microscope (AFM) were used to characterize the dispersion and surface morphology of the Fe3O4 NPs and the PI nanocomposites. The obtained optical band gap of the nanocomposites characterized using Ultraviolet-Visible Diffuse Reflectance Spectroscopy (UV-Vis DRS) was decreased with increasing the Fe3O4 loading. Differential scanning calorimetry (DSC) results showed a continuous increase of Tg with increasing the Fe3O4 NPs loading. Some differences were observed in the onset decomposition temperature between the pure PI and nanocomposites since the NPs and the PI matrix were physically entangled together to form the nanocomposites. The contact angle of pure PI was larger than that of Fe3O4/PI nanocomposites films, and increased with increasing the loading of Fe3O4. The degree of swelling was increased with increasing the Fe3O4 loading and the swelling time. The dielectric properties of the nanocomposite were strongly related to the Fe3O4 loading levels. The Fe3O4/PI magnetic property also had been improved with increasing the loading of the magnetic nanoparticles

    A Designed Framework for Delivering Systems Thinking Skills to Small Business Managers

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    Many small businesses suffer from inadequate management skills which can lead to poor business performance and unsustainable businesses. Research to date has focused on traditional skills such as communication, time management and people skills, yet critically many business managers have no systems thinking skills. This paper presents a framework targeted at delivering systems thinking skills to managers of small businesses utilizing some key characteristic of small business managers. The design is also based on a systems analysis and guided by both adult learning theory and teaching theory. The quality of a training framework depends on the quality of the content design and the right training delivery methods. The systems thinking skills training framework structured systems thinking knowledge into three modules in order to meet the needs of different levels of managers. The framework advocates blended training delivery methods and it also presents possible pitfalls based on training experiences. Additionally, the framework incorporates a continuous improvement process for ongoing systemic improvement

    Single-Cell Analysis Differentiates the Effects of p53 Mutation and p53 Loss on Cell Compositions of Oncogenic Kras-Driven Pancreatic Cancer

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    Pancreatic ductal adenocarcinoma (PDAC) is a devastating malignant disease with a dismal prognosis. In the past decades, a plethora of genetically engineered mouse models (GEMMs) with autochthonous pancreatic tumor development have greatly facilitated studies of pancreatic cancer. Commonly used GEMMs of PDAC often harbor the oncogenic KRAS driver mutation (KrasG12D), in combination with either p53 mutation by knock-in strategy (Trp53R172H) or p53 loss by conditional knockout (Trp53cKO) strategy, in pancreatic cell lineages. However, the systematic comparison of the tumor microenvironment between KrasG12D; Trp53R172H (KPmut) mouse models and KrasG12D; Trp53cKO (KPloss) mouse models is still lacking. In this study, we conducted cross-dataset single-cell RNA-sequencing (scRNA-seq) analyses to compare the pancreatic tumor microenvironment from KPmut mouse models and KPloss mouse models, especially focusing on the cell compositions and transcriptomic phenotypes of major cell types including cancer cells, B cells, T cells, granulocytes, myeloid cells, cancer-associated fibroblasts, and endothelial cells. We identified the similarities and differences between KPmut and KPloss mouse models, revealing the effects of p53 mutation and p53 loss on oncogenic KRAS-driven pancreatic tumor progression

    The best salt solution parameter to describe seed/seedling responses to saline and sodic salts

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    Background and aims Results of studies on plant responses to salt stress often are difficult to compare because different salt parameters were used. Our aim was to compare the effects of different combinations of sodium salts on germination/seedling growth of two forage species and determine which salt solution parameter(s) was(were) most closely related to these responses. Methods Seeds of the legume Medicago sativa and the grass Elymus dahuricus were germinated in different concentrations of saline and sodic salts. Various parameters of the salt solutions were determined, and seed germination and seedling growth metrics were measured. Results Seeds of both species were more tolerant to saline than to sodic salts, and seedlings of E. dahuricus were more salt tolerant than those of M. sativa. Na2SO4 and Na2CO3 were more inhibitory to germination/growth of the two study species than the same concentration of NaCl and NaHCO3 for saline and sodic salts, respectively. For both species, electrical conductivity, salt content (%) and Na+ concentration best correlated with germination/growth for saline salts and Na+ concentration for sodic salts. Conclusions In evaluating the effects of salt on seed germination and seedling growth, both saline and sodic salts need to be considered, and Na+ concentration is the best salt solution parameter to use in comparing and communicating the results

    Effect of LULC change on surface runoff in urbanization area,

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    ABSTRACT In recent decades, urbanization has become a significant urban environmental and ecological concern, especially in most developing countries. In China, rapid urban sprawl has had a profound influence on runoff and results in larger and more frequent incidents of flooding in many urban areas. Therefore, evaluating the impacts of urbanization on runoff is of great important for urban planning policy makers and water/land resource management. The objective of this paper is to present a case study to derive land use/land cover (LULC) maps and further to investigate the long-term effects of LULC change on surface runoff in the fast urbanizing Beijing city. The LULC maps were derived from Landsat TM/ETM+ imagery (acquired in 1986, 1992, 1999, 2006, and 2009 respectively) using support vector machine (SVM) method. A Long-Term Hydrologic Impact Assessment (L-THIA) model was applied to assess the impacts of LULC change on surface runoff. Results indicated that the selected study area experienced rapid urbanization from 1986 to 2009. Urban areas increased from 4.18% in 1986 to 12.78% in 2009 in the whole area. Our results also indicated that the long-term surface runoff increased 25% in the whole area from 1986 to 2009, and the runoff increase was highly correlated with urban expansion (R 2 = 0.91). This research can provide a simple method for policy makers to assess potential hydrological impacts of future planning and development activities
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