504 research outputs found

    Effect of Mycorrhizal Inoculation on Growth and Nutrient Uptake by Leek (Allium porrum) fertilized with Inorganic N Combined with Saturated Polonite

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    The continuous rise in global population continues to increase the demand for food. Meeting this rise in demand requires an increase in agricultural input, such as applying fertilizers, including phosphorus (P). This results in a surge in demand and acquisition of P from non-renewable phosphate rocks from natural reserves in areas such as Morocco, USA and Russia. Rise in political unrest within Morocco and between Russia and Ukraine pose threats to global trade and supply. Continuous accumulation of P in soil due to P application increases the risk of aquatic eutrophication. Inoculation with arbuscular mycorrhizal fungi (AMF) can potentially improve plant P uptake and reduce fertilizer input dependence. The need to apply principles of the circular economy such that recycled P fertilizers used for crop production are also used responsibly in crop cultivation is crucial for phosphorus-importing countries, sustainable food production, food security and the environment. This study, therefore, aimed to determine the effect of mycorrhizal inoculation on growth, Nitrogen (N) and P uptake by host plant (leek) fertilized with P-saturated polonite combined with either ammonium sulfate or nitrate. The study involved an incubation and a cultivation experiment. The incubation experiment was designed to determine the effect of nitrogen application using three levels of ammonium sulfate (200 mg/pot, 400 mg/pot, and 600 mg/pot), each supplying 50, 100, and 150% of 140mg N/L and ammonium nitrate (370.06 mg/pot) supplying 150% of 140mg N/L on soil pH, and phosphorus availability in the soil and from 9g per pot of saturated polonite (PO) added. The cultivation experiment was designed to determine AMF inoculation on growth and P uptake by leek (Allium porrum) fertilized with 9g of saturated polonite, 400 mg/pot of ammonium sulfate and 247.06 mg/pot of ammonium nitrate per standardized rate of N application (140 mg N/L soil). AMF inoculation significantly and positively influenced above-ground biomass, shoot P concentration and uptake by the plants under (-) PO conditions but did not affect P uptake and P acquisition efficiency (%) under (+) PO conditions. Other nutrients, including potassium, sodium and magnesium, were significantly influenced by AMF inoculation. Saturated polonite addition significantly and positively influenced soil P concentration, plant above-ground biomass, shoot P concentration and uptake. Saturated polonite also significantly increased soil pH compared to control but negatively affected ammonium-N in the soil. Root colonization was positively influenced by AMF inoculation, but there was no correlation observed between root colonization and P uptake. Ammonium sulfate at 100% before incubation and 150% after incubation reduced soil pH compared to control. Nitrogen (N) addition overall affected shoot concentration and uptake of Na, S and Mn. Ammonium sulfate and nitrate positively influenced soil N availability, but did not affect soil P availability and negatively influenced shoot P concentration and uptake compared to control treatment. Ammonium sulfate supplied at 150% (600 mg/pot) reduced soil pH compared to control after incubation. When applied to PO treatments, ammonium sulfate (100%) positively influenced shoot fresh and dry weight compared to ammonium nitrate. The study concluded that AMF inoculation may increase plant growth (above-ground biomass), shoot P concentrations and uptake, but this depends on whether soil P is enough due to P addition or deficiency in the soil. In addition, saturated polonite as a P fertilizer alternative can potentially increase plant growth (above-ground biomass), shoot P concentration and uptake

    WILLINGNESS-TO-PAY FOR ATTRIBUTES OF HEALTH CARE FACILITIES IN RURAL KENTUCKY

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    Background: As rural hospitals in Kentucky face insolvency, stakeholders must assess the value of rural hospitals as well as alternatives such as rural clinics and private physician offices. Objective: To identify the value of attributes of healthcare facilities based on Kentucky’s rural residents’ willingness-to-pay (WTP). Methods: A survey instrument was created and distributed to ten counties in rural Kentucky. A conditional logit model was used to obtain baseline values and then a mixed logit model was used to address heterogeneity among consumers in estimating WTP. WTP values incorporated respondents’ demographic characteristics and their health status from self-reported frequency of use of medical services and distance from these services. Results: The results indicate that on average respondents were willing to pay 69.90eachyearfortheattributeofafacilitythattreatspatientswhethertheyhavehealthinsuranceornot,comparedtoafacilitythatonlyacceptspatientswithprivatehealthinsurance.Uninsuredresidentswerewillingtopay69.90 each year for the attribute of a facility that treats patients whether they have health insurance or not, compared to a facility that only accepts patients with private health insurance. Uninsured residents were willing to pay 81.15 for this attribute level. Conclusion: The study suggests that uninsured residents value this attribute level of a facility that grants them access to care. Stakeholders may justify such welfare benefit amounts in support of the establishment or maintenance of such a facility

    CORPORATE SOCIAL RESPONSIBILITIES OF GHANAIAN COMPANIES: PROSPECTS, CHALLENGES AND THE WAY FORWARD

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      Corporate social responsibility is a means whereby most corporations make contributions to the society in which they operate. The emergence of industrialization in the late nineteenth and early twentieth centuries brought in its trail a lot of harmful effects such as pollution, environmental degradation, forest depletion which compelled societies to require many corporations to use part of their profit to correct the harm so caused.   For the past two decades, companies have been giving back to their communities a share of the benefits they have reaped from the environment. It can thus be assumed that corporate social responsibility does really enhance the economic benefits and the image of the firms or companies involved.   It is therefore recommended to Ghanaian firms not only to have a documented social responsibility policy but also to ensure that such a policy is adequately publicized and implemented

    Exploring the Magnitude, Characteristics and Socio-economic Contexts of Witchcraft-Related Eldercides in Kenya

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    Many eldercides in African societies are motivated by witchcraft beliefs. Yet, witchcraft-related eldercide remains an understudied criminological subject. The present study explores the scale, features and socio-cultural and economic contexts of witchcraft-related elder homicide in Kenya. A total of 94 media articles reporting the witchcraft-related killings of 136 older people in Kenya between January 2012 and December 2021 were perused. Key information about the victims and perpetrators and the circumstances surrounding each event/eldercide was collected and critically analysed. The data suggest that approximately 75% of witchcraft-related homicide victims in Kenya are 60 years old and above. Most victims were females (mainly widows) of low socio-economic backgrounds. All the cases occurred in rural communities, and the perpetrators were largely young adult males. Arson, slashing with a machete and clubbing/beating were the dominant methods used to kill alleged witches. Most killings were motivated by the belief that the victims caused misfortunes/calamities by witchcraft. However, witchcraft allegations and concomitant killings were sometimes weaponized to obtain the victims' property/land. Because witchcraft beliefs are deeply entrenched in the culture and philosophy of the Kenyan people, the use of a multifaceted approach may be the most appropriate way of curtailing the problem.</p

    Colonisation of lettuce by Listeria monocytogenes and its biofilm formation : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Food Microbiology at Massey University, Manawatu, New Zealand

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    Foodborne outbreaks associated with fresh produce due to pathogenic bacteria such as Listeria monocytogenes (L. monocytogenes) are increasing. A survey conducted as part of this study showed 5% of bagged lettuces sold at retail outlets contained L. monocytogenes. The ability of L. monocytogenes to form biofilms is a concern in terms of fresh produce safety. The use of hydroponics (growing plants in nutrient solution without using soil) in fresh produce production is a more controlled environment than soil, and therefore may be easier to prevent pathogen contamination. The aim of this study was to determine whether hydroponic grown lettuce and UV-C stress can reduce the colonization, growth and biofilm formation of three fresh produce related strains of L. monocytogenes: PFR O8A06 (coleslaw isolate), PFR O8A07 and PFR O8A08 (cabbage isolates) on lettuce. Evaluation of the nutrient content and indigenous microbiota between hydroponic and soil grown lettuces revealed significant differences. 16S rRNA amplicon sequencing of the bacterial community associated with hydroponically grown lettuce showed that it was more diverse than soil-grown lettuce. Pseudomonas was found to be the dominant bacteria on hydroponically grown lettuce while Bacillus was found to be dominant in soil grown lettuce. There was no significant difference (p > 0.05) in L. monocytogenes attachment to both hydroponic and soil grown lettuce leaves under minimal exposure times. Exposure of lettuce to 5 log CFU/ml for just one second resulted in at least 0.77 log CFU/cm² attachment. L. monocytogenes was able to survive and grow on both lettuce leaf surfaces at 4 and 10°C. Both hydroponic and soil grown lettuce leaf extracts enhanced the survival, growth and biofilm formation of L. monocytogenes on stainless steel coupons, representing surfaces in lettuce processing plants. The results of this study demonstrate the ability of L. monocytogenes to colonize and form biofilms on lettuce irrespective of the growth system used. Finally, UV-C (1.3 kJm⁻²) on lettuce produced a stress response in the plants that reduced L. monocytogenes attachment, survival and growth at pre-harvest. Further exploration of this technique may enhance the microbial safety of lettuce

    An Efficient Methodology for Learning Bayesian Networks

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    Statistics from the National Cancer Institute indicate that 1 in 8 women will develop Breast cancer in their lifetime. Researchers have developed numerous statistical models to predict breast cancer risk however physicians are hesitant to use these models because of disparities in the predictions they produce. In an effort to reduce these disparities, we use Bayesian networks to capture the joint distribution of risk factors, and simulate artificial patient populations (clinical avatars) for interrogating the existing risk prediction models. The challenge in this effort has been to produce a Bayesian network whose dependencies agree with literature and are good estimates of the joint distribution of risk factors. In this work, we propose a methodology for learning Bayesian networks that uses prior knowledge to guide a collection of search algorithms in identifying an optimum structure. Using data from the breast cancer surveillance consortium we have shown that our methodology produces a Bayesian network with consistent dependencies and a better estimate of the distribution of risk factors compared with existing method

    An Exponential Time Differencing Scheme with a Real Distinct Poles Rational Function for Advection-Diffusion Reaction Equations

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    A second order Exponential Time Differencing (ETD) scheme for advection-diffusion reaction systems is developed by using a real distinct poles rational function for approximating the underlying matrix exponential. The scheme is proved to be second order convergent. It is demonstrated to be robust for reaction-diffusion systems with non-smooth initial and boundary conditions, sharp solution gradients, and stiff reaction terms. In order to apply the scheme efficiently to higher dimensional problems, a dimensional splitting technique is also developed. This technique can be applied to all ETD schemes and has been found, in the test problems considered, to reduce computational time by up to 80%
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