849 research outputs found

    Perception Of Farmers About Profitability Of Vegetable Gardening Enterprise In Ahiazu Mbaise Local Government Area Of Imo State, Nigeria

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    This study assessed perception of farmers about profitability of vegetable gardening enterprise in Ahiazu Mbaise local government area of Imo state, Nigeria. A structured questionnaire was administered to 60 randomly selected farmers in the study area. Data collected were analysed using frequencies, percentages and mean scores. Results showed that majority of the respondents (70%) were married, with mean age of 37 years. About 78% of the farmers had secondary education. The mean farm size was 9 plots. Most of the respondents (67%) perceived that vegetable gardening was profitable. The average monthly amount spent was N765 while an average revenue of N1200 was realized from vegetable production in the area. The average profit was N435, which is very low. It was recommended among others that farmers should form co-operative societies to enable them acquire enoughland for gardening. Government should provide appropriate materials and technologies that will help to reduce the labour involved in the production of vegetables

    The Development And Adoption Of Improved Land Management Practices Under The Intensified Agricultural Production System In Anambra State, Nigeria

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    In present day Anambra State, increased population densities, growing food and market demands, urbanization, proximity to major road infrastructure, soil conditions and deterioration in quality of land for agricultural purposes have brought about reduced agricultural productivity. These changes have resulted to increasing socio-economic pressure on land and differential access to farmland and intensification of cultivation with far-reaching consequences for land-use management practices and the sustainability of the agricultural system. Severe soil fertility and productivity decline, ecological damages including soil erosion losses, flood and gullies are some of the out comes of the uncontrolled land-use and agricultural intensification in the state. These problems might worsen in future due to the fragile, heavily weathered and leached nature of the soil. This situation can only be corrected by the incorporation of improved soil conservation practices in our farming system through acceleration of farmer\'s adoption rates of the recommended innovations

    The role of bioenergy and biochemicals in CO2 mitigation through the energy system - a scenario analysis for the Netherlands

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    Bioenergy as well as bioenergy with carbon capture and storage are key options to embark on cost-efficient trajectories that realize climate targets. Most studies have not yet assessed the influence on these trajectories of emerging bioeconomy sectors such as biochemicals and renewable jet fuels (RJFs). To support a systems transition, there is also need to demonstrate the impact on the energy system of technology development, biomass and fossil fuel prices. We aim to close this gap by assessing least-cost pathways to 2030 for a number of scenarios applied to the energy system of the Netherlands, using a cost-minimization model. The type and magnitude of biomass deployment are highly influenced by technology development, fossil fuel prices and ambitions to mitigate climate change. Across all scenarios, biomass consumption ranges between 180 and 760 PJ and national emissions between 82 and 178 Mt CO2. High technology development leads to additional 100-270 PJ of biomass consumption and 8-20 Mt CO2 emission reduction compared to low technology development counterparts. In high technology development scenarios, additional emission reduction is primarily achieved by bioenergy and carbon capture and storage. Traditional sectors, namely industrial biomass heat and biofuels, supply 61-87% of bioenergy, while wind turbines are the main supplier of renewable electricity. Low technology pathways show lower biochemical output by 50-75%, do not supply RJFs and do not utilize additional biomass compared to high technology development. In most scenarios the emission reduction targets for the Netherlands are not met, as additional reduction of 10-45 Mt CO2 is needed. Stronger climate policy is required, especially in view of fluctuating fossil fuel prices, which are shown to be a key determinant of bioeconomy development. Nonetheless, high technology development is a no-regrets option to realize deep emission reduction as it also ensures stable growth for the bioeconomy even under unfavourable conditions.</p

    Circulating mediators of inflammation and immune activation in AIDS-related non-Hodgkin lymphoma

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    Background: Non-Hodgkin lymphoma (NHL) is the most common AIDS-related malignancy in developed countries. An elevated risk of developing NHL persists among HIV-infected individuals in comparison to the general population despite the advent of effective antiretroviral therapy. The mechanisms underlying the development of AIDS-related NHL (A-NHL) are not fully understood, but likely involve persistent B-cell activation and inflammation. Methods: This was a nested case-control study within the ongoing prospective Multicenter AIDS Cohort Study (MACS). Cases included 47 HIV-positive male subjects diagnosed with high-grade B-cell NHL. Controls were matched to each case from among participating HIV-positive males who did not develop any malignancy. Matching criteria included time HIV+ or since AIDS diagnosis, age, race and CD4+ cell count. Sera were tested for 161 serum biomarkers using multiplexed beadbased immunoassays. Results: A subset of 17 biomarkers, including cytokines, chemokines, acute phase proteins, tissue remodeling agents and bone metabolic mediators was identified to be significantly altered in A-NHL cases in comparison to controls. Many of the biomarkers included in this subset were positively correlated with HIV viral load. A pathway analysis of our results revealed an extensive network of interactions between current and previously identified biomarkers. Conclusions: These findings support the current hypothesis that A-NHL develops in the context of persistent immune stimulation and inflammation. Further analysis of the biomarkers identified in this report should enhance our ability to diagnose, monitor and treat this disease. © 2014 Nolen et al

    The effect of coating architecture and defects on the corrosion behaviour of a PVD multilayer Inconel 625/Cr coating

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    This paper investigates the effect of substrate surface finish and deposition conditions of PVD multilayer Inconel 625/Cr coatings on their ability to act as a corrosion-barrier. The corrosion-barrier performance of the coatings was characterized by potentiodynamic testing and salt-spray testing followed by image analysis of the exposed surface; further coating properties were investigated through XRD, SEM, EDX and scratch testing. The results show that multilayering produced the expected improvement in scratch resistance however it did not affect corrosion behaviour. Interrupting the deposition process did not decrease the defect density. Defect density was observed to reduce with decreasing substrate surface finish. The corrosion barrier performance of the multilayer Inconel 625/Cr coating (bp100 nm) was greatly improved for coatings deposited on a polished substrate. For the multilayer Inconel 625/Cr coating system used in this work multilayering and process interruption did not prevent defects from limiting the corrosion barrier effectiveness of the coatings. Corrosion barrier performance was successfully enhanced by the use of low roughness substrates to minimise the defect density

    Cold gas accretion in galaxies

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    Evidence for the accretion of cold gas in galaxies has been rapidly accumulating in the past years. HI observations of galaxies and their environment have brought to light new facts and phenomena which are evidence of ongoing or recent accretion: 1) A large number of galaxies are accompanied by gas-rich dwarfs or are surrounded by HI cloud complexes, tails and filaments. It may be regarded as direct evidence of cold gas accretion in the local universe. It is probably the same kind of phenomenon of material infall as the stellar streams observed in the halos of our galaxy and M31. 2) Considerable amounts of extra-planar HI have been found in nearby spiral galaxies. While a large fraction of this gas is produced by galactic fountains, it is likely that a part of it is of extragalactic origin. 3) Spirals are known to have extended and warped outer layers of HI. It is not clear how these have formed, and how and for how long the warps can be sustained. Gas infall has been proposed as the origin. 4) The majority of galactic disks are lopsided in their morphology as well as in their kinematics. Also here recent accretion has been advocated as a possible cause. In our view, accretion takes place both through the arrival and merging of gas-rich satellites and through gas infall from the intergalactic medium (IGM). The infall may have observable effects on the disk such as bursts of star formation and lopsidedness. We infer a mean ``visible'' accretion rate of cold gas in galaxies of at least 0.2 Msol/yr. In order to reach the accretion rates needed to sustain the observed star formation (~1 Msol/yr), additional infall of large amounts of gas from the IGM seems to be required.Comment: To appear in Astronomy & Astrophysics Reviews. 34 pages. Full-resolution version available at http://www.astron.nl/~oosterlo/accretionRevie

    Postcopulatory sexual selection

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    The female reproductive tract is where competition between the sperm of different males takes place, aided and abetted by the female herself. Intense postcopulatory sexual selection fosters inter-sexual conflict and drives rapid evolutionary change to generate a startling diversity of morphological, behavioural and physiological adaptations. We identify three main issues that should be resolved to advance our understanding of postcopulatory sexual selection. We need to determine the genetic basis of different male fertility traits and female traits that mediate sperm selection; identify the genes or genomic regions that control these traits; and establish the coevolutionary trajectory of sexes

    Human place and response learning: navigation strategy selection, pupil size and gaze behavior.

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    In this study, we examined the cognitive processes and ocular behavior associated with on-going navigation strategy choice using a route learning paradigm that distinguishes between three different wayfinding strategies: an allocentric place strategy, and the egocentric associative cue and beacon response strategies. Participants approached intersections of a known route from a variety of directions, and were asked to indicate the direction in which the original route continued. Their responses in a subset of these test trials allowed the assessment of strategy choice over the course of six experimental blocks. The behavioral data revealed an initial maladaptive bias for a beacon response strategy, with shifts in favor of the optimal configuration place strategy occurring over the course of the experiment. Response time analysis suggests that the configuration strategy relied on spatial transformations applied to a viewpoint-dependent spatial representation, rather than direct access to an allocentric representation. Furthermore, pupillary measures reflected the employment of place and response strategies throughout the experiment, with increasing use of the more cognitively demanding configuration strategy associated with increases in pupil dilation. During test trials in which known intersections were approached from different directions, visual attention was directed to the landmark encoded during learning as well as the intended movement direction. Interestingly, the encoded landmark did not differ between the three navigation strategies, which is discussed in the context of initial strategy choice and the parallel acquisition of place and response knowledge

    Plasma leptin and insulin-like growth factor I levels during acute exacerbations of chronic obstructive pulmonary disease

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    <p>Abstract</p> <p>Background</p> <p>Recent studies have provided evidence for a link between leptin and tumor necrosis factor-alpha (TNF-α). Insulin-like growth factor I (IGF-I) mediates the metabolic effects of growth hormone (GH). The GH axis is believed to be suppressed in chronic obstructive pulmonary disease (COPD). The aim of this study is to find out whether acute exacerbations of COPD are followed by changes in plasma leptin and insulin-like growth factor I (IGF-I) levels and furthermore, whether these changes are related to systemic inflammation.</p> <p>Methods</p> <p>We measured serum leptin, IGF-I, TNF-α, interleukin 1β (IL-1β), interleukin 6 (IL-6) and interleukin 8 (IL-8) levels in 52 COPD patients with acute exacerbation on admission to hospital (Day 1) and two weeks later (Day 15). 25 healthy age-matched subjects served as controls. COPD patients were also divided into two subgroups (29 with chronic bronchitis and 23 with emphysema). Serum leptin and IGF-I were measured by radioimmunoassay and TNF-α, IL-1β, IL-6 and IL-8 were measured by ELISA.</p> <p>Results</p> <p>Serum leptin levels were significantly higher and serum IGF-I levels significantly lower in COPD patients on Day 1 than in healthy controls (p < 0.001). A positive correlation was observed between leptin and TNF-α on Day 1 (r = 0.620, p < 0.001). Emphysematous patients had significantly lower IGF-I levels compared to those with chronic bronchitis both on Day 1 and Day 15 (p = 0.003 and p < 0.001 respectively).</p> <p>Conclusion</p> <p>Inappropriately increased circulating leptin levels along with decreased IGF-I levels occured during acute exacerbations of COPD. Compared to chronic bronchitis, patients with emphysema had lower circulating IGF-I levels both at the onset of the exacerbation and two weeks later.</p

    Molecular and cellular mechanisms underlying the evolution of form and function in the amniote jaw.

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    The amniote jaw complex is a remarkable amalgamation of derivatives from distinct embryonic cell lineages. During development, the cells in these lineages experience concerted movements, migrations, and signaling interactions that take them from their initial origins to their final destinations and imbue their derivatives with aspects of form including their axial orientation, anatomical identity, size, and shape. Perturbations along the way can produce defects and disease, but also generate the variation necessary for jaw evolution and adaptation. We focus on molecular and cellular mechanisms that regulate form in the amniote jaw complex, and that enable structural and functional integration. Special emphasis is placed on the role of cranial neural crest mesenchyme (NCM) during the species-specific patterning of bone, cartilage, tendon, muscle, and other jaw tissues. We also address the effects of biomechanical forces during jaw development and discuss ways in which certain molecular and cellular responses add adaptive and evolutionary plasticity to jaw morphology. Overall, we highlight how variation in molecular and cellular programs can promote the phenomenal diversity and functional morphology achieved during amniote jaw evolution or lead to the range of jaw defects and disease that affect the human condition
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