What Are the Advantages and Disadvantages of the Matrix Form of Structure Essay Example for Free

What Are the Advantages and Disadvantages of the Matrix Form of Structure Essay Organisational structure refers to the way that tasks and responsibilities are allocated to individuals and the ways that individuals are grouped together into offices, departments, and divisions. Mangers often describe their organisation by drawing an organisation chart which shows the structure of an organisation and the relationships and relative ranks of its profits and positions. When small businesses are started, they consist of an owner, manager and a few employees so an organisational structure is unnecessary at this stage. As an organisation grows to become an established business, it will adopt one of a number of organisational structures to implement its strategy. There are a number of different structures (the allocation of tasks and responsibilities to individuals) an organisation can choose. They include a functional structure, multidivisional structure or a matrix structure. The matrix structure is more complex than the other forms of structure. It combines different structural dimensions simultaneously, for example, product divisions and geographical territories or product divisions and functional specialism. The matrix structure has certain advantages and disadvantages: Advantages: 1.They are effective at knowledge management because they allow separate areas of knowledge to be integrated across organisation boundaries. Particularly in professional services organisations. Can be helpful in applying particular knowledge specialism to different market or geographic segments. E.g. for a particular client – people with particular knowledge specialism (strategy/organisational design) tied with people grouped with particular markets (industry sectors or geographic regions.  Example: education specialists – various age groups 2.Matrix organisations are very flexible because they allow different dimensions of the organisation to be mixed together. It is particularly attractive to organisations operating globally, because they of possible mix between local and global dimensions. For example, local marketing in geographical divisions and global product divisions. 3.The matrix structure replaces formal lines of authority with (cross matrix) structures or dual dimensions. This can lead to problems and disadvantages of the matrix structure. Disadvantages: 1.It will typically take longer to make decisions because of bargaining between the managers of different dimensions. 2.There may also be conflict because staff may find themselves responsible to managers from two structural dimensions. In short, matrix organisations are hard to control. 3.Jobs and responsibilities of staff across the matrix may not be clear, i.e. one ‘arm’ of the matrix may work for another ‘arm’ of the matrix (economic production volumes over local variations). 4.Cost and profit responsibilities can be unclear. Senior managers must be good at sustaining collaborative relationships across the matrix and strategically leading and guiding employees.

The Impact Of Tourism On Water Consumption Tourism Essay

The Impact Of Tourism On Water Consumption Tourism Essay Tourism is the major economic sector for many countries around the world especially for small island developing states. . The major growth of the tourism industry started in the 1980s culmination increasing coastal development with major investments in hotels Mauritius is now a well established high class tourist resort destination and tourism is the third pillar of the Mauritian economy after the export processing zone manufacturing sector and agriculture. It contributes significantly to economic growth and has been a key factor in the overall development of Mauritius. In the past two decades tourist arrivals increased at an average annual rate of 9% and in 2000, gross tourism receipts contributed about 11% of the GDP of Mauritius. (CSO, 2007)) The plan of the government is targeting 2.0 million tourists from 2015 to 2020. The strategy for the development of the Tourism sector takes its base in the Tourism Development Plan (2002). It presents a twenty year vision which sees the tourism industry growing but ensuring that environmental and social issues are addressed to the benefit of the people of Mauritius (Min .of Environment and NDU). The Action Plan includes private sector investments in tourist accommodation, tourist attractions, and ancillary facilities, public sector investment in tourism support programmes (e.g. roads, car parking, water and sewage schemes), infrastructure and critical tourism product improvements, diversification and innovations, human resource development/social projects and environmental management support. There will be an accompanying demand for services for high quality up-market tourists with specially trained staff and hotel rooms including trained tour guides and support services such as flight bookings, airline operations, etc. Tourism and water The industry is also a major consumer of water resources and impacting heavily on water demand of island states. The problem of water supply is further exacerbated by the impact of climate change. Tourism industry relies also on a safe and reliable supply of water. With the goal of attracting 2M tourists by 2015 in Mauritius the intensive tourism development that will follow will have a major impact on our natural resources (CSD, 1996). It has been growing rapidly and impacting on the natural resources of the host countries. Overexploitation of water resources can impact negatively on ecosystems which are major components of its tourism industry. Competition for water resources by the tourism sector and domestic population is a global problem exacerbated by the climate change (Goodwin, 2007). Mauritius is facing each year prolong drought problems during the dry season where it is also the peak tourist period. Over extraction and lowering of ground water table can lead to eventually the depletion of aquifers as it is not replenished as rapidly it is consumed. Pollution from sea water intrusion will further limit the availability of freshwater. The latter will be more apparent with sea level rise due to global warming (Goodwin, 2007). The tourism industry faces two issues with regards to water as a resource namely how it affects distribution of water and secondly the impact of the industrys consumption on the environment and the availability of water (Goodwin, 2007). For the development of large resorts, especially in water scarcity areas, the water available for the local people is deviated to provide for these resorts (Goodwin, 2007). In many places water is diverted to provide for tourists and thus leaving indigenous population short of water. European Environment Agency (2003) in its assessment reported that tourists consume up to 300 Litres (up to 880 Litres for luxury tourism) and generate around 180L of wastewater per day. The number of tourists visiting particular places is season dependent and is not constant all year round and tends to be concentrated in places which have limited water resources (Garcia and Servera, 2003). There are conflicts of interests as the tourism industry is able to buy water at higher prices whereas the poorer population will have more frequent water shortage (Goodwin, 2007). In Tunisia groundwater resources that were important for agriculture were diverted to provide for the tourism industry and thus creating a new problem of dried out land that are unarable and had to be abandoned. The European Tourism Study Group report 2007 conclude that hotels are high consumers of water, as a tourist staying in a hotel uses on average one third more water per day than a local inhabitant. The desalination of sea water on a large scale is a measure affordable to countries with high revenues such as United Arab Emirates and Maldives which have oil resources (Dluzewska, 2008). LAND USE PATTERNS in Tourism: Tourism is being given special attention with respect to its actual and potential impacts in land use (Rico-Amoros, et al., 2008). The tourism distribution is not homogenous for many countries and the different forms and types of tourism have different water requirement (Gossling, 2001). Water consumption by the tourism sector is not well documented by statistics at present. More complete information on water demand of tourism and its different subsector ( second homes, facilities, activities etc,) is needed by state and local authorities to define priorities for water conservation or demand management programs ( Hof. et al, 2011). Rico-Amoros et al. (2008) mentioned that the development of tourism in Mediterranean region is enhancing pressure on water demand because there high numbers of tourists at specific period and summer droughts which further decrease the availability of water. However, from closer study of the different type of tourists, Rico-Amoros et al (2008) found out tha t concentration of tourists such as in hotels tend to use comparatively less water than disperse, low density residential resorts. Hof and Schmitt (2011) found out that increase water consumption is directly related to the low-density residential tourist land use due to outdoor uses such as swimming pools and gardens comparing with tourists in hotels. The research of Hof and Schmitt (2011) concluded that in summer 70% of the total water consumption in the residential tourist areas is used for gardens irrigation which has been identified as the main cause for increase in water consumption. The additional pressure on water use is from individually own swimming pools which accounts for 22 litres/person/day as shown by Hof and Schmitt (2011). Hotels with golf courses were analysed for their water consumption patterns and regression analysis demonstrated that the size and price were important factors that will influence the water use by golf courses (Gopalakrishnan, 2003). Resorts and ho tels golf courses are heavy water users and for small islands the problem is urgent as there is limited resources of drinking water, and thus the water must be judiciously managed ( Graefe and Vaske, 1987). Benchmarks for water use in guest rooms in litres per guest night Good Fair Poor Temperate 250 250-300 >300 Mediterranean 270 270-320 >320 Tropical 300 300-350 >350 Source IBLF WWF-UK (2005) p.19 Mauritius as SIDS: its vulnerability Small Island States are mostly dependent on their natural environment for promoting tourism development but paradoxically the tourism development appear to be a fast track to social and economic development and thus little care is given for the ecosystem (CSD, 1996). The environment impacts of tourism are more consequent in Small Island States due to its limited land space and freshwater resource. Land is use to build infrastructures and facilities for tourists along with hotels and the new trend of residential houses or apartment. Rising prices of building land increase the pressure to build on agricultural land as the tourism sector is more lucrative. In many countries including Mauritius, there has been unchecked construction along the coast whereby the original pristine beauty of these areas has been changed in favour of urbanization since the development of the tourism sector (CSD, 1996). It is only recently that governments are taking measures through legislations to protect th e natural resources and promote sustainable. development. Over the past years, there has been a drastic increase in water demand from the different economic and demographic sectors, which in general is leading the country to a water stressed situation. Mauritius and its water resources According to the United Nations Development Programme (UNDP) Human Development Report, Mauritius is already facing a situation of water stress because it has a supply of 1083 m3 per person per year (based on actual population), which is below the norm of 1 700m3 per person per year. Mauritius is expected to suffer from water scarcity by 2020 with a projected supply of 974 m3 per person per year (based on a projected population of 1 335 000). Although the figures can be interpreted in various ways, they provide an indication of the problems that Mauritius may face in the future regarding water supply. The water sector faces a number of challenges resulting from increasing demand from the different sectors. New dams are planned to be built and reduction in unaccounted for water are being envisaged with big investment in new pipe networks. Diversification of the tourism product-IRS in Mauritius In view to attract more foreign investment Mauritius has recently introduced a new type of development namely the Integrated Resort Schemes (IRS) whereby resorts are being constructed that include hotels, residential villas and golf courses. Since 2005 there has been an increase in the number of resorts and golf courses though the financial crisis has put a halt to this rapid increase. These developments have put further pressure to the scarce water resources. In Mauritius strategies are being put in place to manage the water resources the demand as well as the supply sides. The IRS promotes the concept of residential tourism with second permanent homes for rich retired or rich celebrities. This market diversification has therefore allowed the development of golf, villas, spas and also permanent second homes or residential that have increased the demand of water from the tourism sector. In encouraging this type of development and targeting more and more tourist this will again have a consequences on the water resources. Mauritius depend on a few number of reservoirs and are already under pressure to supply for the domestic, industrial, agricultural and tourism sector. The tourist hotel mainly the large ones have started to have desalination plants to have constant supply of water. Due to high water demand Mauritius has reached almost its limits in terms of underground resources. The table below shows the water requirements till 2050. Table 1:Water requirements in Mauritius (Proag, V., 2006, Water Resources Management in Mauritius. European Water 15/16: 45-57) Available Water resources and climate change could however have an impact on the diversification strategy thereby causing a decline of growth in the tourism sector especially if these water crises are not well managed. (Essex et al, 2004) Residential Tourism or second homes The different types of tourist accomodation and new type of residential tourism do not consume water resources similarly. The golf courses are consuming more and more water for irrigation purposes. A.Hof et al (2011) have shown that outdoor uses such as swimming pools, garden irrigation are also have a high impact on water resources. As determined by a study (Gopalakrishnan and Cox 2003) shows that number of units of swimming pools and golf courses will determine the consumption of water. Aim of paper To develop appropriate strategies for the management of the water resources information on the tourism sector demand for water and the different usage will be required. There is however an information gap with regards to its impact on water resources . This paper will try to show the influence of tourism: hotel, non hotel and residential on the scarce water resources and thereby assist in developing a strategy for a sustainable tourism.

Normal Occlusion And Its Characteristics

Normal Occlusion And Its Characteristics The development of human dentition from adolescence to adulthood has been the subject of extensive study by numerous dentists, orthodontists and other experts in the past. While prevention and cure of dental diseases, surgical reconstitution to address teeth anomalies and research studies on teeth and development of the dental arch during the growing up years has been the main concerns across the past decades, in recent years, substantial effort has been evident in the field of mathematical analysis of the dental arch curve, particularly of children from varied age groups and diverse ethnic and national origins. The proper care and development of the primary dentition into permanent dentition is of major importance and the dental arch curvature, whose study has been related intimately by a growing number of dentists and orthodontists to the prospective achievement of ideal occlusion and normal permanent dentition, has eluded a proper definition of form and shape. Many eminent authors have put forth mathematical models to describe the teeth arch curve in humans. Some have imagined it as a parabola, ellipse or conic while others have viewed the same as a cubic spline. Still others have viewed the beta function as best describing the actual shape of the dental arch curve. Both finite mathematical functions as also polynomials ranging from 2nd order to 6th order have been cited as appropriate definitions of the arch in various studies by eminent authors. Each such model had advantages and disadvantages, but none could exactly define the shape of the human dental arch curvature and factor in its features like shape, spacing and symmetry/asymmetry. Recent advances in imaging techniques and computer-aided simulation have added to the attempts to determine dental arch form in children in normal occlusion. This paper presents key mathematical models compares them through some secondary research study. Keywords: Dental Arch,Normal Occlussion,Mixed Dentition INTRODUCTION Primary dentition in children needs to be as close as possible to the ideal in order that during future adulthood, the children may exhibit normal dental features like normal mastication and appearance, space and occlusion for proper and healthy functioning of permanent dentition. Physical appearance does directly impact on the self-esteem and inter-personal behaviour of the human individual, while dental health challenges like malocclusions, dental caries, gum disease and tooth loss do require preventive and curative interventions right from childhood so that permanent dentition may be normal in later years. Prabhakaran, S., et al, (2006) maintain that the various parts of the dental arch during childhood, viz., canine, incisor and molar play a vital role in shaping space and occlusion characteristics during permanent dentition and also stress the importance of the arch dimensions in properly aligning teeth, stabilizing the form, alleviating arch crowding, and providing for a normal overbite and over jet, stable occlusion and a balanced facial profile. Both research aims and clinical diagnosis and treatment have long required the study of dental arch forms, shape, size and other parameters like over jet and overbite, as also the spacing in deciduous dentition. In fact, arch size has been seen to be more important than even teeth size (Facal-Garcia et al., 2001). While various efforts have been made to formulate a mathematical model for the dental arch in humans, the earliest description of the arch was via terms like elliptic, parabolic, etc and, also, in terms of measurement, the arch circumference, width and depth were some of the previous methods for measuring the dental arch curve. Various experts have defined the dental arch curvature through use of biometry by measurement of angles, linear distances ratios (Brader, 1972; Ferrario et al., 1997, 1999, 2001; Harris, 1997; Braun et al., 1998; Burris and Harris, 2000; Noroozi et al., 2001). Such analysis, ho wever, has some limitations in describing a three-dimensional (3D) structure like the dental arch (Poggio et al., 2000). Whereas, there are numerous mathematical models and geometrical forms that have been put forth by various experts, no two models appear to be clearly defined by means of a single parameter (Noroozi, H., et al, 2001). DEFINING THE DENTAL ARCH Models for describing the dental arch curvature include conic sections (Biggerstaff, 1972; Sampson, 1981), parabolas (Jones Richmond, 1989), cubic spline curves (BeGole, E.A., 1980), catenary curves (Battagel, J.M., 1996), and polynomials of second to eight degree (Pepe, S.H., 1975), mixed models and the beta function (Braun, et al, 1998). The definitions differ as because of differences in objectives, dissimilarity of samples studied and diverse methodologies adopted and uniform results in defining and arriving at a generalized model factoring in all symmetries and asymmetries of curvature elude experts even today. Some model may be suitable in one case while others may be more so in another situation. In this respect, conic sections which are 2nd order curves, can only be applied to specific shapes like hyperbolas, eclipse, etc and their efficiency as ideal fit to any shape of the dental arch is thus limited (AlHarbi, S, et al, 2006). The beta function, although superior, consider s only the parameters of molar width and arch depth and does not factor in other dental landmarks. Nor does it consider asymmetrical forms. In contrast, the 4th order polynomial functions are better effective in defining the dental arch than either cubic spline or the beta function (AlHarbi, et al, 2006). AlHadi and others (2006) also maintain that important considerations in defining the human dental arch through mathematical modelling like symmetry or asymmetry, objective, landmarks used and required level of accuracy do influence the actual choice of model made. OCCLUSION AND ITS TYPES Occlusion is the manner in which the lower and upper teeth intercuspate between each other in all mandibular positions or movements. Ash Ramfjord (1982) state that it is a result of neuromuscular control of the components of the mastication systems viz., teeth, maxilla mandibular, periodontal structures, temporomandibular joints and their related muscles and ligaments. Ross (1970) also differentiated between physiological and pathological occlusion, in which the various components function smoothly and without any pain, and also remain in good health. Furthermore, occlusion is a phenomenon that has been generally classified by experts into three types, namely, normal occlusion, ideal occlusion and malocclusion. Ideal Occlusion Ideal occlusion is a hypothetical state, an ideal situation. McDonald Ireland (1998) defined ideal occlusions as a condition when maxilla and mandible have their skeletal bases of correct size relative to one another, and the teeth are in correct relationship in the three spatial planes at rest. Houston et al (1992) has also given various other concepts relating to ideal occlusion in permanent dentition and these concern ideal mesiodistal buccolingual inclinations, correct approximal relationships of teeth, exact overlapping of upper and lower arch both laterally and anteriorly, existence of mandible in position of centric relation, and also presence of correct functional relationship during mandibular excursions. Normal Occlusion and its Characteristics Normal occlusion was first clearly defined by Angle (1899) which was the occlusion when upper and lower molars were in relationship such that the mesiobuccal cusp of upper molar occluded in buccal cavity of lower molar and teeth were all arranged in a smoothly curving line. Houston et al, (1992) defined normal occlusion as an occlusion within accepted definition of the ideal and which caused no functional or aesthetic problems. Andrews (1972) had previously also mentioned of six distinct characteristics observed consistently in orthodontic patients having normal occlusion, viz., molar relationship, correct crown angulation inclination, absence of undesirable teeth rotations, tightness of proximal points, and flat occlusal plane (the curve of Spee having no more than a slight arch and deepest curve being 1.5 mm). To this, Roth (1981) added some more characteristics as being features of normal occlusion, viz., coincidence of centric occlusion and relationship, exclusion of posterior t eeth during protrusion, inclusion of canine teeth solely during lateral excursions of the mandible and prevalence of even bilateral contacts in buccal segments during centric excursion of teeth. Oltramari, PVP et al (2007) maintain that success of orthodontic treatments can be achieved when all static functional objectives of occlusion exist and achieving stable centric relation with all teeth in Maxim intercuspal position is the main criteria for a functional occlusion MATHEMATICAL MODELS FOR MEASURING THE DENTAL ARCH CURVE Whether for detecting future orthodontic problems, or for ensuring normal occlusion, a study of the dental arch characteristics becomes essential. Additionally, intra-arch spacing also needs to be studied so as to help the dentist forecast and prevent ectopic or premature teeth eruption. While studies in the past on dentition in children and young adults have shown significant variations among diverse populations (Prabhakaran et al, 2006), dentists are continuously seized of the need to generalize their research findings and arrive at a uniform mathematical model for defining the human dental arch and assessing the generalizations, if any, in the dental shape, size, spacing and other characteristics. Prabhakaran et al (2006) also maintain that such mathematical modelling and analysis during primary dentition is very important in assessing the arch dimensions and spacing as also for helping ensure a proper alignment in permanent dentition during the crucial period which follows the co mplete eruption of primary dentition in children. They are also of the view that proper prediction of arch variations and state of occlusion during this period can be crucial for establishing ideal desired esthetic and functional occlusion in later years. While all dentists and orthodontists seem to be more or less unanimous in perceiving as important the mathematical analysis of the dental arch in children in normal occlusion, no two experts seem agreeable in defining the dental arch by means of a single generalized model. A single model eludes the foremost dental practitioners owing to the differences in samples studied with regard to their origins, size, features, ages, etc. Thus while one author may have studied and derived his results from studying some Brazilian children under some previously defined test conditions, another author may have studied Afro-American children of another age group, sample size or geographical origins. Also, within the same set of samples studied, there are also marked variations in dental arch shapes, sizes and spacing as found out by leading experts in the field. Shapes are also unpredictable as to the symmetry or asymmetry and this is another obstacle to the theoretical generalization that could evo lve a single uniform mathematical model. However, some notable studies in the past decades do stand out and may be singled out as the most relevant and significant developments in the field till date. The earliest models were necessarily qualitative, rather than quantitative. Dentists talked of ellipse, parabola, conic section, etc when describing the human dental arch. Earlier authors like Hayashi (1962) and Lu (1966) did attempt to explain mathematically the human dental arch in terms of polynomial equations of different orders. However, their theory could not explain asymmetrical features or predict fully all forms of the arch. Later on, authors like Pepe (1975), Biggerstaff (1972), Jones Richmond (1989), Hayashi (1976), BeGole (1980) made their valuable contributions to the literature in the dental field through their pioneering studies on teeth of various sample populations of children in general, and a mathematical analysis of the dental arch in particular. While authors like Pepe and Biggerstaff relied on symmetrical features of dental curvature, BeGole was a pioneer in the field in that he utilized the asymmetrical cubic splines to describe the dental arch. His model assu med that the arch could not be symmetrical and he tried to evolve a mathematical best fit for defining and assessing the arch curve by using the cubic splines. BeGole developed a FORTRAN program on the computer that he used for interpolating different cubic splines for each subject studied and essentially tried to substantiate a radical view of many experts that the arch curve defied geometrical definition and such perfect geometrical shapes like the parabola or ellipse could not satisfactorily define the same. He was of the view that the cubic spline appropriately represented the general maxillary arch form of persons in normal occlusion. His work directly contrasted efforts by Biggerstaff (1972) who defined the dental arch form through a set of quadratic equations and Pepe who used polynomial equations of degree less than eight to fit on the dental arch curve (1975). In Pepes view, there could be supposed to exist, at least in theory, a unique polynomial equation having degree (n + 1) or less (n was number of data points) that would ensure exact data fit of points on the dental arch curve. An example would be the polynomial equation based on Le-Granges interpolation formula viz., Y = n Ã¢â‚¬Å"i=1yi Ã‚ [j ¹i](x-xj)/xi-xj), where xi, yi were data points. In 1989, Jones Richmond used the parabolic curve to explain the form of the dental arch quite effectively. Their effort did contribute to both pre and post treatment benefits based on research on the dental arch. However, Battagel (1996) used the catenary curves as a fit for the arch curvature and published the findings in the popular British Journal of Orthodontics, proving that the British researchers were not far behind their American counterparts. Then, Harris (1997) made a longitudinal study on the arch form while the next year (1998), Braun and others put forth their famous beta function model for defining the dental arch. Braun expressed the beta function by means of a mathematical equation thus: In the Braun equation, W was molar width in mm and denoted the measured distance between right and left 2nd molar distobuccal cusp points and D the depth of the arch. A notable thing was that the beta function was a symmetrical function and did not explain observed variations in form and shape in actual human samples studied by others. Although it was observed by Pepe (1975) that 4th order polynomials were actually a better fit than the splines, in later analyses in the 1990s, it appeared that these were even better than the beta (AlHarbi et al, 2006). In the latter part of the 1990s, Ferrario et al (1999) expressed the dental curve as a 3-D structure. These experts conducted some diverse studies on the dental arch in getting to know the 3-D inclinations of the dental axes, assessing arch curves of both adolescents and adults and statistically analysing the Monsons sphere in healthy human permanent dentition. Other key authors like Burris et al (2000), who studied the maxillary arch sizes and shapes in American whites and blacks, Poggio et al (2000) who pointed out the deficiencies in using biometrical methods in describing the dental arch curvature, and Noroozi et al (2001) who showed that the beta function was solely insufficient to describe an expanded square dental arch form, perhaps, constitute some of the most relevant mathematical analyses of recent years. Most recently, one of the most relevant analyses seems to have been carried out by AlHarbi ad others (2006) who essentially studied the dental arch curvature of individuals in normal occlusion. They studied 40 sets of plaster dental casts both upper and lower of male and female subjects from ages 18 to 25 years. Although their samples were from adults, they considered four most relevant functions, namely, the beta function, the polynomial functions, the natural cubic splines, and the Hermite cubic splines. They found that, whereas the polynomials of 4th order best fit the dental arch exhibiting symmetrical form, the Hermite cubic splines best described those dental arch curves which were irregular in shape, and particularly useful in tracking treatment variations. They formed the opinion at the end of their study of subjects all sourced, incidentally, from nationals of Saudi Arabia that the 4th order polynomials could be effectively used to define a smooth dental arch curve which could further be applied into fabricating custom arch wires or a fixed orthodontic apparatus, which could substantially aid in dental arch reconstruction or even in enhancement of esthetic beauty in patients. COMPARISON OF DIFFERENT MODELS FOR ANALYSING THE DENTAL ARCH The dental arch has emerged as an important part of modern dentistry for a variety reasons. The need for an early detection and prevention of malocclusion is one important reason whereby dentists hope to ensure a normal and ideal permanent dentition. Dentists also increasingly wish to facilitate normal facial appearance in case of teeth and space abnormalities in children and adults. What constitutes the ideal occlusion, ideal intra-arch and adjacent space and correct arch curvature is a matter of comparison among leading dentists and orthodontists. Previous studies done in analyzing dental arch shape have used conventional anatomical points on incisal edges and on molar cusp tips so as to classify forms of the dental arch through various mathematical forms like ellipse, parabola, cubical spline, etc, as has been mentioned in the foregoing paragraphs. Other geometric shapes used to describe and measure the dental arch include the catenary curves. Hayashi (1962) used mathematical equations of the form: y = axn + e Ã‚ ¡(x- Ã‚ ¢) and applied them to anatomic landmarks on buccal cusps and incisal edges of numerous dental casts. However, the method was complex and required estimation of the parameters like Ã‚ ¡, Ã‚ ¢, etc. Also, Hayashi did not consider the asymmetrical curvature of the arch. In contrast, Lu (1966) introduced the concept of fourth degree polynomial for defining the dental arch curve. Later, Biggerstaff (1973) introduced a generalized quadratic equation for studying the close fit of shapes like the parabol a, hyperbola and ellipse for describing the form of the dental arch. However, sixth degree polynomials ensured a better curve fit as mentioned in studies by Pepe, SH (1975). Many authors like Biggerstaff (1972) have used a parabola of the form x2 = -2py for describing the shape of the dental arch while others like Pepe (1975) have stressed on the catenary curve form defined by the equation y = (ex + e-x)/2. Biggerstaff (1973) has also mentioned of the equation (x2/b2) + (y2/a2) = 1 that defines an ellipse. BeGole (1980) then developed a computer program in FORTRAN which was used to interpolate a cubic spline for individual subjects who were studied to effectively find out the perfect mathematical model to define the dental arch. The method due to BeGole essentially utilized the cubic equations and the splines used in analysis were either symmetrical or asymmetrical. Another method, finite element analysis used in comparing dental-arch forms was affected by homology function and the drawbacks of element design. Another, multivariate principal component analyses, as performed by Buschang et al (1994) so as to determine size and shape factors from numerous linear measurements could not satisfactorily explain major variations in dental arch forms and the method failed to provide for a larger generalization in explaining the arch forms. ANALYSING DENTAL ARCH CURVE IN CHILDREN IN NORMAL OCCLUSION Various studies have been conducted by different experts for defining human dental arch curves by a mathematical model and whose curvature has assumed importance, particularly in prediction, correction and alignment of dental arch in children in normal occlusion. The study of children in primary dentition have led to some notable advances in dental care and treatment of various dental diseases and conditions, although, an exact mathematical model for the dental arch curve is yet to be arrived at. Some characteristic features that have emerged during the course of various studies over time indicate that no single arch form could be found to relate to all types of samples studied since the basic objectives, origin and heredity of the children under study, the drawbacks of the various mathematical tools, etc, do inhibit a satisfactory and perfect fit of any one model in describing the dental arch form to any degree of correction. However, it has been evident through the years of continu ous study by dentists and clinical orthodontists that children exhibit certain common features during their childhood, when their dentition is yet to develop into permanent dental form. For example, a common feature is the eruption of primary dentition in children that generally follows a fixed pattern. The time of eruption of various teeth like incisors, molars, canines, etc follow this definite pattern over the growing up years of the child. The differences of teeth forms, shape, size, arch spacing and curvature, etc, that characterize a given sample under study for mathematical analysis, also essentially vary with the nationality and ethnic origin of a child. In one longitudinal study by Henrikson et al (2001) that studied 30 children of Scandinavian origin with normal occlusion, it was found that when children pass from adolescence into adulthood, a significant lack of stability in arch form was discernible. In another study, experts have also indicated that dental arches in som e children were symmetrical, while in others this was not so, indicating that symmetrical form of a dental arch was not a prerequisite for normal occlusion. All these studies based on mathematical analysis of one kind or another have thrown up more data rather than been correlated to deliver a generalized theory that can satisfactorily associate a single mathematical model for all dental arch forms in children with normal occlusion. CONCLUSION Factors that determine satisfactory diagnosis in orthodontic treatment include teeth spacing and size, the dental arch form and size. Commonly used plaster model analysis is cumbersome, whereas many scanning tools, like laser, destructive and computer tomography scans, structured light, magnetic resonance imaging, and ultrasound techniques, do exist now for accurate 3-D reconstruction of the human anatomy. The plaster orthodontic methods can verily be replaced successfully by 3-D models using computer images for arriving at better accurate results of study. The teeth measurement using computer imaging are accurate, efficient and easy to do and would prove to be very useful in measuring tooth and dental arch sizes and also the phenomenon of dental crowding. Mathematical analysis, though now quite old, can be applied satisfactorily in various issues relating to dentistry and the advances in computer imaging, digitalization and computer analysis through state-of-the-art software program s, do herald a new age in mathematical modelling of the human dental arch which could yet bring in substantial advancement in the field of Orthodontics and Pedodontics. This could in turn usher in an ideal dental care and treatment environment so necessary for countering lack of dental awareness and prevalence of dental diseases and inconsistencies in children across the world.

Definition Essay - Defining Freedom -- Expository Definition Essays

Definition Essay – Defining Freedom Is it possible to define freedom? To define freedom is more than a difficult task, but perhaps easier than one might imagine if not overanalyzed. Given ample time to consider the task, however, a simple, sufficient definition can present itself: freedom is the ability to choose, for any creature living life in any place in any time. There is no greater truth to the statement, and no underlying meanings; freedom is simply the ability to choose. So one might ask, "If this ability to choose applies to all creatures in all places in all times, why can freedom only be defined in the context of the specific creature whose definition of freedom is concerned?" That is simple. Freedom is something that can only be experienced to some extent; there is no such thing as absolute freedom. However, each varying life form has differing boundaries to which this freedom can conform. If such a thing as absolute freedom were to exist, then those who possessed it could do absolutely anything imaginable. One could then wonder, if there is th...

Characterizing the Religious Encounter between Moravians and Saramakas

Characterizing the Religious Encounter between Moravians and Saramakas When Moravians in Germany sent three missionaries to Suriname in 1765 to witness to the Saramakas, two groups with unique and fundamentally different cultural, social, and religious beliefs and structures met. During the course of their stay, the Moravians were hounded by disease and disappointed by the poor reception of the gospel; meanwhile, the Saramakas were plagued with inter-tribal rivalries and poor relations with the white government officials and plantation owners, with whom they maintained an unsteady peace. These circumstances, as well as the many ways in which Moravian and Saramaka expectations and social behavior differed, created a barrier between the two groups. Because the Moravians entered Saramaka society in small numbers and with no pretense of using political force or monetary bribery (the latter of which the Saramakas would likely have accepted) to force conversions, the extent of their influence on Saramaka religion and culture was limited. Though there was s ome cultural exchange, including the adoption of European manufactured goods into Saramaka life and the adoption of some Saramaka medical treatments by the Moravians, for the Moravians and for the majority of Saramakas, the religious encounter was a meeting of mutually closed worlds. For a handful of Saramakas, including Alabi, an apparently true conversion took place. In addition to the few converts, there were a small number (Brother Wietz reports twelve in 1779) of Saramakas who came to Christian services regularly, and thus were interested in and perhaps persuaded to some degree by the missionaries’ message, but made no commitment to or identification with Christianity and c... ...vian presence certainly changed the lives of a few Saramakas, but did not make a great impact on Saramaka society as a whole. The missionaries who died or returned to Germany did not manage to build relationships with the Saramaka community as a whole and could not count Suriname as one of their fruitful mission endeavors. Conversion was rare, and the syncretism formed after the Moravians introduced Christianity was admonished by the Moravians themselves and short-lived in any case. The current presence of Christianity, or some syncretic form, among a minority of Saramakas is probably not derived from the Moravians. Though Christian stories and the Moravian presence will never be forgotten because of their importance in the life of the gaama Alabi, the importance of the encounter with Moravians is restricted to a specific place and time in Saramaka history.

Physics Lab

In the Tumble Buggy Lab, my partners and I used several different methods to calculate the velocity of a Tumble Buggy. The methods we used were a meter stick and a timer, a Spark Timer, a Photogate, and a Motion Sensor. Each method was different but overall, our velocities were very similar. Using the meter stick and timer, our velocity was 0. 22 m/s. With the spark timer, our velocity was 0. 26 m/s. Next, the velocity found with the Photogate was 0. 325 m/s. Finally, when we used the motion sensor, we found our velocity to be 0. 34 m/s. This lab is prone to some mechanical and human error.First, the meter stick and timer method. This method is the least accurate because it is the most subject to human error. While doing this method, one person must time the car as it moves a distance of one meter. This can be very inaccurate because the timer could start the timer to early or to late and could stop the timer to early or to late. Next we have the Spark Timer. This method uses special tapes and burns small holes into the tape every tenth of a second. The Spark Timer is very accurate and the timing is very precise. Our third trial was the Photogate.I believe that this device is the most accurate because it measures the speed at which a flag placed on top of the buggy passes through a infrared beam, breaking the beam. The final trial was the motion sensor. Although this device is accurate it is subject to human error. This error comes into play when the person is starting and stopping the buggy in the motion sensor. The error is that you cannot be sure if the motion sensor is hitting the buggy at all times, effecting the data. Overall, I believe that this lab went well but if I were to redo the lab, I would definitely have more than one trial using each device.

Personal Statement CELTA TBI Essay

I would like the opportunity to partake in the CELTA course at TBI, so I am able to increase my knowledge and experience, whilst simultaneously being able to assist students’ in their own understanding of the English language. By gaining the CELTA qualification at your institute, I will be equipped to continually encourage my students’ towards reaching their language goals by building on the foundation of knowledge they already have. My future aims and intentions are to train to be a teacher of extremely high standard, and once I have obtained my CELTA certificate and gained some more practical knowledge within schools; I am particularly interested in completing my Post Graduate Certificate of Education (PGCE). The CELTA course would be greatly beneficial in helping me gain valuable experience in preparation for my future PGCE. Having lived in Jakarta for a few years, I am able to empathize with some the hardships involved in learning a new language. It is important to build rapport with the student whilst still maintaining professionalism. As I am able to appreciate the difficulties each student may face, I feel this would contribute towards creating an enjoyable, yet fulfilling, learning environment. Allowing the students to see you (the teacher) as approachable and encouraging, whilst still upholding a professional relationship is a key aspect of encouraging students’ to pursue their language goals. I am a confident, hardworking, highly motivated team player, able to make decisions in a high pressure environment. I understand the importance of diligence and role versatility when tailoring lesson plans to suit the strengths and weaknesses of each individual student. It is of great significance that these individually tailored lessons do not impact the whole class negatively, but rather, enable interaction between those students of a similar skill level. My previous involvement completing my bachelor degree and distance learning diploma, shows that I am able to complete assignments to the highest standard I am able to achieve. For the distance learning Diploma, it was essential to organise and manage my time productively, to ensure sufficient researching, planning and writing time were allocated accordingly, enabling me to complete each of the necessary components on schedule. Throughout my time at both University and College, I was a member of the student representative committees, liaising between the student body and departmental teams. This has helped me gain confidence and familiarity when dealing with my peers and those in higher authority  positions alike. I have learnt how to be patient and diplomatic when the need arises, as well as being able to ascertain when to use my own initiative. The opportunity to undertake studying my CELTA with your institution, allows me to not only better myself, but also the students that I will be teaching. I feel it is an extremely rewarding course, and the large array of possibilities that open up on completion of the CELTA, is endless and exciting. The knowledge and practical experience I would gain from obtaining a CELTA qualification is vast and would enable me to kick start my teaching career.