60 research outputs found
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Effects of conversion of native cerrado vegetation to pasture on soil hydro-physical properties, evapotranspiration and streamflow on the Amazonian agricultural frontier
Understanding the impacts of land-use change on landscape-hydrological dynamics is one of the main challenges in the Northern Brazilian Cerrado biome, where the Amazon agricultural frontier is located. Motivated by the gap in literature assessing these impacts, we characterized the soil hydro-physical properties and quantified surface water fluxes from catchments under contrasting land-use in this region. We used data from field measurements in two headwater micro-catchments with similar physical characteristics and different land use, i.e. cerrado sensu stricto vegetation and pasture for extensive cattle ranching. We determined hydraulic and physical properties of the soils, applied ground-based remote sensing techniques to estimate evapotranspiration, and monitored streamflow from October 2012 to September 2014. Our results show significant differences in soil hydro-physical properties between the catchments, with greater bulk density and smaller total porosity in the pasture catchment. We found that evapotranspiration is smaller in the pasture (639 ± 31% mm yr-1) than in the cerrado catchment (1,004 ± 24% mm yr-1), and that streamflow from the pasture catchment is greater with runoff coefficients of 0.40 for the pasture and 0.27 for the cerrado catchment. Overall, our results confirm that conversion of cerrado vegetation to pasture causes soil hydro-physical properties deterioration, reduction in evapotranspiration reduction, and increased streamflow
The development and preliminary psychometric properties of two positive psychology outcome measures for people with dementia: the PPOM and the EID-Q.
Background:
Positive psychology research in dementia care has largely been confined to the qualitative literature because of the lack of robust outcome measures. The aim of this study was to develop positive psychology outcome measures for people with dementia.
Methods:
Two measures were each developed in four stages. Firstly, literature reviews were conducted to identify and operationalise salient positive psychology themes in the qualitative literature and to examine existing measures of positive psychology. Secondly, themes were discussed within a qualitative study to add content validity for identified concepts (n = 17). Thirdly, draft measures were submitted to a panel of experts for feedback (n = 6). Finally, measures were used in a small-scale pilot study (n = 33) to establish psychometric properties.
Results:
Salient positive psychology themes were identified as hope, resilience, a sense of independence and social engagement. Existing measures of hope and resilience were adapted to form the Positive Psychology Outcome Measure (PPOM). Due to the inter-relatedness of independence and engagement for people with dementia, 28 items were developed for a new scale of Engagement and Independence in Dementia Questionnaire (EID-Q) following extensive qualitative work. Both measures demonstrated acceptable internal consistency (α = .849 and α = .907 respectively) and convergent validity.
Conclusions:
Two new positive psychology outcome measures were developed using a robust four-stage procedure. Preliminary psychometric data was adequate and the measures were easy to use, and acceptable for people with dementia
Dimethylaminoparthenolide and gemcitabine: a survival study using a genetically engineered mouse model of pancreatic cancer
BACKGROUND: Pancreatic cancer remains one of the deadliest cancers due to lack of early detection and absence of effective treatments. Gemcitabine, the current standard-of-care chemotherapy for pancreatic cancer, has limited clinical benefit. Treatment of pancreatic cancer cells with gemcitabine has been shown to induce the activity of the transcription factor nuclear factor-kappaB (NF-κB) which regulates the expression of genes involved in the inflammatory response and tumorigenesis. It has therefore been proposed that gemcitabine-induced NF-κB activation may result in chemoresistance. We hypothesize that NF-κB suppression by the novel inhibitor dimethylaminoparthenolide (DMAPT) may enhance the effect of gemcitabine in pancreatic cancer. METHODS: The efficacy of DMAPT and gemcitabine was evaluated in a chemoprevention trial using the mutant Kras and p53-expressing LSL-Kras(G12D/+); LSL-Trp53(R172H); Pdx-1-Cre mouse model of pancreatic cancer. Mice were randomized to treatment groups (placebo, DMAPT [40 mg/kg/day], gemcitabine [50 mg/kg twice weekly], and the combination DMAPT/gemcitabine). Treatment was continued until mice showed signs of ill health at which time they were sacrificed. Plasma cytokine levels were determined using a Bio-Plex immunoassay. Statistical tests used included log-rank test, ANOVA with Dunnett’s post-test, Student’s t-test, and Fisher exact test. RESULTS: Gemcitabine or the combination DMAPT/gemcitabine significantly increased median survival and decreased the incidence and multiplicity of pancreatic adenocarcinomas. The DMAPT/gemcitabine combination also significantly decreased tumor size and the incidence of metastasis to the liver. No significant differences in the percentages of normal pancreatic ducts or premalignant pancreatic lesions were observed between the treatment groups. Pancreata in which no tumors formed were analyzed to determine the extent of pre-neoplasia; mostly normal ducts or low grade pancreatic lesions were observed, suggesting prevention of higher grade lesions in these animals. While gemcitabine treatment increased the levels of the inflammatory cytokines interleukin 1α (IL-1α), IL-1β, and IL-17 in mouse plasma, DMAPT and DMAPT/gemcitabine reduced the levels of the inflammatory cytokines IL-12p40, monocyte chemotactic protein-1 (MCP-1), macrophage inflammatory protein-1 beta (MIP-1β), eotaxin, and tumor necrosis factor-alpha (TNF-α), all of which are NF-κB target genes. CONCLUSION: In summary, these findings provide preclinical evidence supporting further evaluation of agents such as DMAPT and gemcitabine for the prevention and treatment of pancreatic cancer
Spatial and temporal variability of urban soil water dynamics observed by a soil monitoring network
Purpose Urban soils’ variability in the vertical direction presumably affects hydrological parameters at the timescale. Moreover, horizontal soil alterations at small spatial scales are common in urban areas. This spatio-temporal variability and heterogeneity of soil moisture and the possible influencing factors were to be described and quantified, using data of a soil monitoring network in the city of Hamburg, Germany. Materials and methods Soil moisture data from ten observation sites within the project HUSCO was evaluated for two different years. The sites were located within districts with different mean groundwater table depths and characteristic urban soil properties. Soil hydrological simulations with SWAP were calculated for a selected site. Results and discussion The temporal evolution of soil water content and tension for the sites was very distinct, related to soil substrate, organic matter content, and groundwater table depth. Impacts of different vegetation rooting depths, the soil substrates’ type, and to some extent the degree of disturbance on soil water dynamics could be identified. An impact of groundwater table depth on the water content of the topsoil during low-precipitation periods could be assumed. The comparison of the results of soil hydrological simulations with empirical data indicated an overestimation of infiltration and percolation for the given soil substrates. Conclusions While soil properties are mainly determinant for the long-term progression of soil hydrology, local site factors affect the short-term regime. A shallow groundwater table contributes to more constant water dynamics while the relative decrease of water during a dry phase is diminished
Cascade of Proppant-Sandwiched Silt Blocks as a Double-Continuum: From Discovery to Mathematical Modeling
Loss of weight in ryegrass and clover roots preserved in ethanol prior to image analysis for root traits
Simulation modelling of variable patterns of water movement through a cracking clay soil
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