Evaluation of WGS-subtyping methods for epidemiological surveillance of foodborne salmonellosis

Background: Salmonellosis is one of the most common foodborne diseases worldwide. Although human infection by non-typhoidal Salmonella (NTS) enterica subspecies enterica is associated primarily with a self-limiting diarrhoeal illness, invasive bacterial infections (such as septicaemia, bacteraemia and meningitis) were also reported. Human outbreaks of NTS were reported in several countries all over the world including developing as well as high-income countries. Conventional laboratory methods such as pulsed field gel electrophoresis (PFGE) do not display adequate discrimination and have their limitations in epidemiological surveillance. It is therefore very crucial to use accurate, reliable and highly discriminative subtyping methods for epidemiological characterisation and outbreak investigation. Methods: Here, we used different whole genome sequence (WGS)-based subtyping methods for retrospective investigation of two different outbreaks of Salmonella Typhimurium and Salmonella Dublin that occurred in 2013 in UK and Ireland respectively. Results: Single nucleotide polymorphism (SNP)-based cluster analysis of Salmonella Typhimurium genomes revealed well supported clades, that were concordant with epidemiologically defined outbreak and confirmed the source of outbreak is due to consumption of contaminated mayonnaise. SNP-analyses of Salmonella Dublin genomes confirmed the outbreak however the source of infection could not be determined. The core genome multilocus sequence typing (cgMLST) was discriminatory and separated the outbreak strains of Salmonella Dublin from the non-outbreak strains that were concordant with the epidemiological data however cgMLST could neither discriminate between the outbreak and non-outbreak strains of Salmonella Typhimurium nor confirm that contaminated mayonnaise is the source of infection, On the other hand, other WGS-based subtyping methods including multilocus sequence typing (MLST), ribosomal MLST (rMLST), whole genome MLST (wgMLST), clustered regularly interspaced short palindromic repeats (CRISPRs), prophage sequence profiling, antibiotic resistance profile and plasmid typing methods were less discriminatory and could not confirm the source of the outbreak. Conclusions: Foodborne salmonellosis is an important concern for public health therefore, it is crucial to use accurate, reliable and highly discriminative subtyping methods for epidemiological surveillance and outbreak investigation. In this study, we showed that SNP-based analyses do not only have the ability to confirm the occurrence of the outbreak but also to provide definitive evidence of the source of the outbreak in real-time

Some factors affecting magnesium uptake by citrus leaves : a thesis presented in partial fulfilment of the requirements for the degree of Master of Horticultural Science at Massey University, Palmerston North, New Zealand

Pineapple sweet orange seedlings and rooted leaf bud cuttings of Meyer lemons were used to investigate the effects of some of the factors affecting magnesium uptake by leaves. Magnesium was determined by thiazole yellow method of Drosdoff and Nearpass (1948) and uptake was usually measured 24 hours after spray treatment. It was shown that the addition of wetting agents to magnesium nitrate sprays significantly increased the uptake of magnesium by leaves. The nonionic wetter (Terric GN9) at the very low (0.01% a.i.) and high (0.08 - 0.1% a.i.) concentrations did. not affect magnesium uptake, whereas at intermediate concentrations, magnesium uptake was increased. Use of the humectant glycerine at 1 or 2 percent significantly increased the uptake of magnesium by leaves, compared with sprays to which no glycerine was added, but had no beneficial effect over sprays which contained a nonionic wetter (Terric GN9). Magnesium uptake by leaves grown in 100% relative humidity for two weeks was greater than the uptake by leaves grown in average relative humidity of 71% Both morning and the evening sprays resulted in greater uptake of magnesium by leaves, compared with afternoon sprays. A significant increase in leaf magnesium concentration occurred after 2 hours of a magnesium nitrate spray application. Leaf magnesium concentration rose steeply for 24 hours after spraying, thereafter remaining constant. (Because it was not possible to measure the degree of magnesium transport out of the leaf, it is not clear whether magnesium uptake, in fact, stopped after 24 hours). Of the three magnesium salts used, magnesium nitrate and magnesium chloride sprays resulted in greater magnesium uptake by leaves, compared with magnesium sulphate sprays. Uptake varied with the concentration of magnesium in. the leaves. The lower the concentration of magnesium in the leaves, the loss the uptake of magnesium by leaves, and the higher the concentration of magnesium, the higher the uptake of magnesium. Leaf nitrogen also affected uptake of magnesium by leaves. High leaf nitrogen (2.92% of dry weight) resulted in greater uptake of magnesium than the low leaf nitrogen (2.08% of dry weight). The average increase in the concentration of magnesium in the leaves of low nitrogen plants was 0.09% of dry weight, while in leaves of high nitrogen plants the increase was 0.19%. Thus the increase in the % leaf concentration of magnesium in the high nitrogen plants was double that of the low nitrogen plants. This may be a direct effect of the low leaf nitrogen or an indirect one due to the induced low leaf magnesium in those plants

Water Resources In Nepal: Institutional Analysis Based On Legal Provisions

Occasional Papers in Sociology and Anthropology - Volume 9, 200

On The Risk Of Unemployment: A Comparative Assessment of the Labour Market Success of Migrants in Australia

One important indicator of the successful assimilation of immigrants is the comparison of the relative success of immigrants and of the native born population in finding employment under different macro economic regimes that affect the overall rate of unemployment in an economy. This paper analyzes the "risk" of unemployment of male immigrants to Australia relative to the native born for two different time periods in which the overall labour market characteristics and the pool of immigrants differ considerably. The two data sets used are the 1990 Income and Housing Costs Survey conducted by the Australian Bureau of Statistics and the first wave of the Household Income and Labour Dynamics in Australia (HILDA) survey whose data refer primarily to the 2001 calendar year. The paper analyzes the correlates of unemployment at the individual level using logistic and probit regression models. It uses both a standard specification of the probability of being unemployed determined by individual and family level socio-economic characteristics (i.e. years of schooling and work experience, age, years since migration, etc.); and an extended model that is feasible only with the extra information available in the HILDA data set. The results show there is a clear disadvantage in the probability of finding employment for migrants with similar characteristics of a native born Australian in both the standard and extended model specifications. There also are very distinct country of birth effects which persist even after controlling for the individual migrant's English language skills. The relative disadvantage of migrants has not diminished between the two time periods in spite of greater emphasis on skilled migration in recent years. By providing a clearer understanding of why and how the individual and subgroup level characteristics are correlated with the probability of an individual being unemployed, this paper gives valuable insights on how the Australian labor market functions, and, in particular on how it evaluates the employment prospects of specific immigrant groups.employment prospects of migrants, immigrant workers and assimilation, unemployment probabilities, immigrants in Australia

The relationship between farm size and productivity: empirical evidence from the Nepalese mid-hills

This paper examines the farm size and productivity relationship using data from Nepalese mid hills. The household data used has been drawn from a survey conducted by the author and financed by the Norwegian University of Life Science. The analysis uses models both allowing for and not allowing for village dummies(as cluster controls), the ratio of irrigated land (as proxy for land quality), and other socio-economic variables such as households, belonging to caste groups, and family size (as proxy for access to resources). The result supported the almost âstylized factâ of inverse relationship (IR) between farm size and output per hectare. Total cash input use and labour hours per hectare were found to be higher on small farms. The findings of regression equations allowing for village dummies and other socio-economic variables do not support the explanation that the IR between farm size and productivity is due to variation in regions as well as access to resources. Nevertheless, family size and caste dummies show some effects on farm value added. The paper further investigates returns to scale in Nepalese agriculture, applying the Cobb-Douglas (CD) production function. The result shows constant returns to scale. Labour input seems more influential in farm production, followed by manure, in the sample farms. The overall result shows that the IR between farm size and output per hectare is perhaps due to the result more of other inputs used by small farms rather than diseconomies of scale.inverse relationship, farm size, productivity, returns to scale, Nepal, Q15, O13, Farm Management,

The relationship between farm size and productivity: empirical evidence from the Nepalese mid-hills

This paper examines the farm size and productivity relationship using data from Nepalese mid hills. The household data used has been drawn from a survey conducted by the author and financed by the Norwegian University of Life Science. The analysis uses models both allowing for and not allowing for village dummies(as cluster controls), the ratio of irrigated land (as proxy for land quality), and other socio-economic variables such as households, belonging to caste groups, and family size (as proxy for access to resources). The result supported the almost ‘stylized fact’ of inverse relationship (IR) between farm size and output per hectare. Total cash input use and labour hours per hectare were found to be higher on small farms. The findings of regression equations allowing for village dummies and other socio-economic variables do not support the explanation that the IR between farm size and productivity is due to variation in regions as well as access to resources. Nevertheless, family size and caste dummies show some effects on farm value added. The paper further investigates returns to scale in Nepalese agriculture, applying the Cobb-Douglas (CD) production function. The result shows constant returns to scale. Labour input seems more influential in farm production, followed by manure, in the sample farms. The overall result shows that the IR between farm size and output per hectare is perhaps due to the result more of other inputs used by small farms rather than diseconomies of scale.inverse relationship; farm size; productivity; returns to scale; Nepal

Strategic planning for a SME

The purpose of this research is to find competitive advantages for an organisation and prepare a long-term strategic planning for the SME. In a New Zealand context, small business enterprises play vital roles in business and the economic sector. However, most small business do not have specific competitive advantage and long-term strategies to compete in the market. Both qualitative and quantitative approaches have been used as mixed method research. Interviews and surveys have been done. Using those methods, researchers are intended to use the most effective implementation methodology to find out the best solution to the problem and cause of a SME. Location and customer satisfaction have been identified as the prime factors for the firm to run the business successfully. The business has been operating smoothly without using any further strategies to compete in the market. Recommendations involve pricing, advertising and stock management