6,546,337 research outputs found
Deformations of zero-dimensional schemes and applications
In this thesis we consider the geometry of the Hilbert scheme of points in
P^n, concentrating on the locus of points corresponding to the Gorenstein
subschemes of P^n. New results are given, most importantly we provide tools for
constructing flat families and analysis of finite Gorenstein algebras and
expose their efficiency by proving smoothability of certain families of
algebras. Much of the existing theory and folklore is reviewed, providing a
micro-encyclopaedic reference.Comment: v2: some minor corrections made. 29 pages. This is an MSc thesis done
on the University of Warsaw; my adviser is Jaros{\l}aw Buczy\'nsk
Agro-industrial Lignocellulosic Biomass: A Sustainable Platform for the Production of α-amylase and xylanase A
Enzymes such as α-amylase and xylanase offer potential for numerous industrial applications such as food, beverage, and animal feed production, detergents, textile, cosmetics and biodiesel production. Economic factors such as achievement of optimum yields and production cost are the main deterrents in the industrial use of these enzymes. Enzymes are generally produced via microbial fermentation using expensive mediums which account for 30 to 40% of the production cost. Food industry wastes such as spent coffee waste (SCW) and Brewers’ spent grain (BSG) are two of the most common food waste products expelled by the food and beverage industry here in Ireland and are environmental burden. However, these inexpensive food wastes can be utilized as a substrate for the production of enzymes, which can significantly reduce the production cost of the enzymes and also enhance the value of underutilized food waste. Based on the above facts, the aim of this study is to exploit the lignocellulosic food industry waste such as BSG and SCW for the production of industrially viable enzymes such as α-amylase and xylanase. Although high in polysaccharide content, the effective utilisation of SCW and BSG requires specific pretreatment measures that result in a decrease in recalcitrance by removal of the lignin fraction. The aim of the project was achieved through the following objectives: ▪ Identification and development of the best pretreatment strategy for SCW and BSG that would enhance their enzymatic digestibility and liberation of higher amount of fermentable sugars. ▪ Optimisation of SCW and BSG for the production of enzymes such as α-amylase and xylanase. The effect of the pretreatments was primarily analysed as changes that occurred in the composition of SCW and BSG. A number of analytical techniques were used to characterise the pretreated waste samples, including FTIR, FESEM, XRD and DSC
Detection of Genetically Modified Foods
In recent years, Genetically Modified (GM) foods have become increasingly common on our supermarket shelves. Consumer concerns regarding their safety have prompted codes of practice and legislation requiring labelling of all GM-food-containing products. Labelling requires some means of verification. There is no simple means of detecting GM food and until recently, there were no tests available. The object of this study was to develop a simple, rapid and user-friendly method of detecting genetically modified foods. The study concentrated on the detection of GM tomatoes, using a commercially available tomato paste. The method of choice was the Polymerase Chain Reaction (PCR) targeting the selectable marker gene Neomycin Phosphotransferase II (NPTII). The selectable marker gene confers resistance to the antibiotic kanamycin, and is used to detect newly transformed plants in the laboratory. NPT II has commonly been used as a selectable marker and therefore can be used to test for many species of transgenic plants. A PCR method to detect NPT II was developed and applied to genetically modified tomato paste. Commonly used plant DNA extraction methods proved unsuitable and an extraction method based on microwave treatment of the paste was developed. This increased both the sensitivity and reproducibility of the PCR method. It was also attempted to develop a method to detect genetically modified soy using PCR, by targeting the cauliflower mosaic virus promoter gene
An Investigation into the Predictive Capability of Customer Spending in Modelling Mortgage Default
The mortgage arrears crisis in Ireland was and is among the most severe experienced on record and although there has been a decreasing trend in the number of mortgages in default in the past four years, it still continues to cause distress to borrowers and vulnerabilities to lenders. There are indications that one of the main factors associated with mortgage default is loan affordability, of which the level of disposable income is a driver. Additionally, guidelines set out by the European Central Bank instructed financial institutions to adopt measures to further reduce and prevent loans defaulting, including the implementation and identification of Early Warning Indicators (EWIs). Financial institutions currently adopt credit risk models in order to calculate the risk associated with customers. Therefore, this research observed a cohort of mortgage customers in Lender A over a 30-month period and utilised transactional features, explaining the use of disposable income, to expand on existing credit risk models and aid in the identification of EWIs for the mortgage portfolio. Over the course of the study three feature selection techniques were adopted, namely correlation-based analysis, random forest feature importance and decision tree feature importance. A number of transactional categories were identified including insurance spend, gambling spend, savings and the value of ATM withdrawals. Furthermore, it was found that the inclusion of transactional features in existing credit risk models statistically improved performance
The Effects of Intraspecific, interSpecific, and Intergeneric Grafting on the Growth and Development of Fraxinus Excelsior Scions
Fraxinus excelsior (common ash) is a hardwood tree, native to Ireland which has demonstrated adaptability to growing in a wide range of sites. In 2013, there was a total of over 20,000 hectares recorded under ash in Ireland. From an economic, ecological and carbon aspect ash is also a very important tree species. Since the arrival of Chalara disease, which has the potential to prove fatal to c.97% of the ash population there is an urgent need to consider how to preserve the remaining resistant trees and propagate new resistant lines. Grafting is the suggested method which has the capacity to produce a tree in a breeding programme which can be field planted within a year, once suitable rootstocks can be determined and produced. This thesis examined the potential for grafting two Fraxinus excelsior clones M72 and 98, chosen at random onto F. excelsior, F. paxiana, F. chinensis, F. japonica, F. platypoda, Syringa vulgaris, and Ligustrum ovalifolium rootstocks to confirm their suitability for large scale vegetative propagation. It was found that when Clone M72 and Clone 98 were grafted onto Fraxinus excelsior rootstocks the survival was 100% and 97% respectively, while the non-grafted Control returned a plant survival rate of 93%. When Clone M72 was grafted onto Fraxinus chinensis and Fraxinus paxiana rootstocks the resultant graft survival was 68% and 40% respectively. When Fraxinus platypoda and Fraxinus japonica interstocks were used for grafting Clone 98 survival was 87% and 60% respectively. When Ligustrum and Syringa rootstocks were used to propagate Clone M72 survival was 37% and 33% respectively. When Ligustrum and Syringa were used as rootstocks for Clone 98 the result was 30% and 40% respectively. Propagation by budding was not successful
The Study of Reconfigurable Antennas and Associated Circuitry
This research focuses on the design of pattern reconfigurable antennas and the associated circuitry. The proposed pattern reconfigurable antenna designs benefit from advantages such as maximum pattern diversity and optimum switching circuits to realise 5G reconfigurable antennas. Whereas MIMO based solutions can provide increased channel capacity, they demand high computational capability and power consumption due to multiple channel processing. This prevents their use in many applications most notably in the Internet of Things where power consumption is of key importance. A switched-beam diversity allows an energy-efficient solution improving the link budget even for small low-cost battery operated IoT/sensor network applications. The main focus of the antenna reconfiguration in this work is for switched-beam diversity. The fundamental switching elements are discussed including basic PIN diode circuits. Techniques to switch the antenna element in the feed or shorting the antenna element to the ground plane are presented. A back-to-back microstrip patch antenna with two hemispherical switchable patterns is proposed. The patch elements on a common ground plane, are switched with a single-pole double-throw PIN diode circuit. Switching the feed selects either of two identical oppositely oriented radiation patterns for maximum diversity in one plane. The identical design of the antenna elements provides similar performance control of frequency and radiation pattern in different states. This antenna provides a simple solution to cross-layer PIN diode circuit designs. A mirrored structure study provides an understanding of performance control for different switching states. A printed inverted-F antenna is presented for monopole reconfigurable antenna design. The proposed low-profile antenna consists of one main radiator and one parasitic element. By shorting the parasitic element to the ground plane using only one PIN diode, the antenna is capable of switching both the pattern and polarisation across the full bandwidth. The switched orthogonal pattern provides the maximum spatial pattern diversity and is realised using a simple structure. Then, a dual-stub coplanar Vivaldi antenna with a parasitic element is presented for the 5G mm-Wave band. The use of a dual-stub coupled between the parasitic element and two tapered slots is researched. The parasitic element shape and size is optimised to increase the realised gain. A bandpass coupled line filter is used for frequency selective features. The use of slits on the outer edge of the ground plane provides a greater maximum gain. This integrated filtenna offers lower insertion loss than the commercial DC blocks. The UWB antenna with an integrated filter can be used for harmonic suppression. The influence of the integrated filter circuit close to the antenna geometry informs the design of PIN diode circuit switching and power supply in the 5G band. Based on the filter design in the mm-Wave band, a method of designing a feasible DC power supply for the PIN diode in the mm-Wave band is studied. A printed Yagi-Uda antenna array is integrated with switching circuitry to realise a switched 180° hemispheres radiation pattern. The antenna realises a maximum diversity in one plane. The study offers the possibility to use PIN diodes in the mm-Wave band for reconfigurable antenna designs. For the presented antennas, key geometric parameters are discussed for improved understanding of the trade-offs in radiation pattern/beamwidth and gain control for reconfigurable antenna applications
English Language Acquisition by Chechen Programme Refugees in Roscommon, Ireland
This research explored the acquisition of English by Programme Chechen refugees who arrived in Ireland ten years ago. Very many of them had less than a basic level of English. To meet the language needs of the newly arrived Chechen Programme refugees an intensive English course was set up by the local Vocational Education Committee. However, refugees’ basic needs such as health care, parental care took precedence over language provision. The research found that they were unable to fully participate in and benefit from the course. The process of acquiring English happened to a large extent outside the classroom. This research also looked at how the Chechens have acquired language outside the classroom and within their social environment since their initial English language course. The collective case study research with a qualitative approach produced a number of findings that complemented each other. The findings from the assessments, the questionnaire, the semi-structured interviews, individual case studies and notes made from empirical observation all reinforced each other. The experiences of the individual personalities which became apparent in the individual case studies also shared a lot in common. This research has shown that the Chechens in Roscommon town have become well integrated; they are independent and plan to stay. Most of them speak English quite well and are continuing to improve by participating in local society. Based on the results of this research, it is recommended that the initial language course for programme refugees should be set up at an appropriate time for them, after a period of time for settlement
Data Mining by Grid Computing in the Search for Extrasolar Planets
A system is presented here to provide improved precision in ensemble differential photometry. This is achieved by using the power of grid computing to analyse astronomical catalogues. This produces new catalogues of optimised pointings for each star, which maximise the number and quality of reference stars available. Astronomical phenomena such as exoplanet transits and small-scale structure within quasars may be observed by means of millimagnitude photometric variability on the timescale of minutes to hours. Because of atmospheric distortion, ground-based observations of these phenomena require the use of differential photometry whereby the target is compared with one or more reference stars. CCD cameras enable the use of many reference stars in an ensemble. The more closely the reference stars in this ensemble resemble the target, the greater the precision of the photometry that can be achieved. The Locus Algorithm has been developed to identify the optimum pointing for a target and provide that pointing with a score relating to the degree of similarity between target and the reference stars. It does so by identifying potential points of aim for a particular telescope such that a given target and a varying set of references were included in a field of view centred on those pointings. A score is calculated for each such pointing. For each target, the pointing with the highest score is designated the optimum pointing. The application of this system to the Sloan Digital Sky Survey (SDSS) catalogue demanded the use of a High Performance Computing (HPC) solution through Grid Ireland. Pointings have thus been generated for 61,662,376 stars and 23,697 quasars
Time-temperature and Relative Humidity Profiles of Chilled and Frozen Foods in Retail Outlets Nationwide, and Evaluation of Related Practices
Temperature abuse combined with poor operational practices are the dominant factors in the mishandling of food products which can result in outbreaks of food borne disease. The objective of this work was to determine efficacy of temperature and relative humidity control using recorded data and to assess the food safety management systems in operation in retail outlets in the Republic of Ireland. This study also aims to examine food safety risk to consumers as a result of inadequate temperature control and poor food hygiene practices using microbial analysis and predictive modelling. External air temperature, core temperature and relative humidity of various chilled and frozen food products were recorded at 5 minute intervals over a 7.5 hour period in butcher, delicatessen and supermarket outlets in each county of Ireland, amounting to 85 commercial establishments. A questionnaire was discussed with employees regarding food safety management systems including hygiene protocol and staff training strategies. Microbial analysis was carried out for Staphylococcus aureus and listeria moncyotogenes in three ready-to-eat chilled foods in 10 retail premises in Dublin city centre to investigate food safety practices. Predictive modelling for growth of both pathogens in chilled foods was done using results from the microbial analysis and temperature data recorded during the nationwide survey. Results showed that in 37% of premises surveyed, temperatures in chill cabinets exceeded 5°C. Frozen food was incorrectly stored in 52% of outlets surveyed. Readings for relative humidity were satisfactory in 36% of premises. There was compliance for the 3 elements of HACCP in 51% of outlets surveyed, with temperature control being the element of HACCP with least compliance. Provision of knowledge alone will not lead to changes in attitude and food handling behaviour, and management motivation is critical to the success of hygiene training. Low hygiene standards and poor temperature control detected in retail outlets suggest that there is a potential risk of food borne diseases as a result of consumption of chilled ‘ready-to-eat’ foods
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