Concept Of Quality Circles Essay Example | Topics and Well Written Essays - 6000 words

Concept Of Quality Circles - Essay Example Quality Circle concept has three major attributes: a) Change in Attitude: The establishment of quality circles brings an attitude change from "I don't care" to "I do care". Also it brings 'Continuous improvement' in quality of work life through humanization of work. A Quality Circle has an appropriate organizational structure for its effective and efficient performance. It varies from industry to industry, organization to organization. But it is useful to have a basic framework as a model. The structure of a Quality Circle consists of the following elements. i. A steering committee: This is at the top of the structure. It is headed by a senior executive and includes representatives from the top management personnel and human resources development people. It establishes policy, plans and directs the program and meets usually once in a month. v. Circle members: They may be staff workers. Without circle members the porgramme cannot exist. They are the lifeblood of quality circles. They should attend all meetings as far as possible, offer suggestions and ideas, participate actively in group process, take training seriously with a receptive attitude. The roles of Steering Committee, Co-ordinator, Facilitator, Circle leader and Circle members are well defined. PROCESS OF OPERATION The operation of quality circles involves a set of sequential steps as under: 1. Problem identification: Identify a number of problems. 2 Problem selection: Decide the priority and select the problem to be taken up first. 3 Problem Analysis: Problem is clarified and analysed by basic problem solving methods. 4 Generate alternative solutions: Identify and evaluate causes and generate number of possible alternative solutions. 5 Select the most appropriate solution : Discuss and evaluate the alternative solutions by comparison in terms of investment and return from the investment. This enables to select the most appropriate solution. 6 Prepare plan of action : Prepare plan of action for converting the solution into reality which includes

Tesla in Turkey Essay Example | Topics and Well Written Essays - 1750 words

Tesla in Turkey - Essay Example The automotive industry is very important after the construction and tourism sectors (Saee 194). This industry creates the country’s highest multiplier. Furthermore, the industry intertwines with other industries such as marketing, fuel, finance, service and insurance. Any changes in the automotive industry are important to the country’s economy. The best approach for Tesla Motors in this country is to cooperate in the production and marketing fields. This increases the company’s capacity in the country’s automotive industry. The company enjoys more economic competition, innovations and investments for new models. In short, the automotive industry in Turkey is lucrative and with the right market entry strategies, Tesla Motors will enjoy significant profits. From a political and legal perspective, the country has liberalization (Nas & Mehmet 41). Turkey is a key supporter of liberal trade and investment policies that permit trade with countries in the Europ ean Union. The custom union of 1996 allowed Turkish firms to expand and become more successful internationally (Altug & Alpay 25). Turkish exports have continuously increased by 10% on an annual basis showing the trading potential of the country. The country charges sales tax, inclusive of VAT and exclusive consumer tax, on all motor vehicles. These taxes are higher compared to those other developed countries. The sales tax comprise of almost 19.2 percent to 117.1 percent. The country’s legislation on motor vehicle changes rapidly depending on changes in technology.

Concept Of Quality Circles Essay Example | Topics and Well Written Essays - 6000 words

Concept Of Quality Circles - Essay Example Quality Circle concept has three major attributes: a) Change in Attitude: The establishment of quality circles brings an attitude change from "I don't care" to "I do care". Also it brings 'Continuous improvement' in quality of work life through humanization of work. A Quality Circle has an appropriate organizational structure for its effective and efficient performance. It varies from industry to industry, organization to organization. But it is useful to have a basic framework as a model. The structure of a Quality Circle consists of the following elements. i. A steering committee: This is at the top of the structure. It is headed by a senior executive and includes representatives from the top management personnel and human resources development people. It establishes policy, plans and directs the program and meets usually once in a month. v. Circle members: They may be staff workers. Without circle members the porgramme cannot exist. They are the lifeblood of quality circles. They should attend all meetings as far as possible, offer suggestions and ideas, participate actively in group process, take training seriously with a receptive attitude. The roles of Steering Committee, Co-ordinator, Facilitator, Circle leader and Circle members are well defined. PROCESS OF OPERATION The operation of quality circles involves a set of sequential steps as under: 1. Problem identification: Identify a number of problems. 2 Problem selection: Decide the priority and select the problem to be taken up first. 3 Problem Analysis: Problem is clarified and analysed by basic problem solving methods. 4 Generate alternative solutions: Identify and evaluate causes and generate number of possible alternative solutions. 5 Select the most appropriate solution : Discuss and evaluate the alternative solutions by comparison in terms of investment and return from the investment. This enables to select the most appropriate solution. 6 Prepare plan of action : Prepare plan of action for converting the solution into reality which includes

Protien Essay Example | Topics and Well Written Essays - 1000 words

Protien - Essay Example Due to presence of a high degree of palindromic sequences changes were made in the 3rd codons for R and A, and the 1st codon for L based on the second priority codon preference. The changes reduced the chances of self-annealing and formation of secondary structures. The new gene sequence was thus: The next step was to choose the restriction enzymes for cutting out the complete gene after it has been cloned to the TOPO vector. NdeI, which cleaves the sequence CA/TATG was chosen for the 5’ end while BPu1102 which cuts GC/TGAGC was selected for the 3’ end. Both restriction enzymes do not have restriction sites in the chosen vector (but are present in the expression vector which will be used for protein expression later). GCGC nucleotides are added before and after the NdeI and BPu1102 sites respectively to act as primer initiation sites for PCR of the final gene sequence which is the following: 2. The PCR-based methods for gene synthesis normally require a DNA template, which is not available for designed peptides, for error-free amplification. To reduce error, nucleotide stretches of the optimized gene sequences are synthesized and ligated to complementary sequences followed by PCR amplification (Tsuchiya, Morioka, Shirai, Yoshida, & Inumaru, 2006) (Young & Dong, 2004). These procedures result in different gene fragments that have errors in the sequences. Further cloning, purification and sequencing for the desired gene sequence is expensive and time-consuming. In this study, the gene will be synthesized using circular assembly amplification, a new technique in gene synthesis that removes error sequences and increases the probability of getting accurate sequences (Bang & Church, 2008). Here, a mixture of short complementary oligonucleotides (~ 50bp), that are designed with overlaps to allow complementary coupling or annealing, generates circular DNA. This is followed by exonuclease treatment to remove

Assessment and Learner Essay Example for Free

Assessment and Learner Essay This discussion paper is part of a series being published and disseminated by the Office of the Queensland School Curriculum Council. The purpose of this series is to encourage discussion on various issues concerning assessment and reporting. Teacher observation is one of several types of assessment techniques recommended by the Council in its Position and Guidelines on Assessment and Reporting for Years 1 to 10 and in its syllabus documents for the key learning areas. Other assessment techniques include consultation, focused analysis, peer assessment and self-assessment. The Position and Guidelines state that: ‘Observation involves teachers in observing students as they participate in planned activities. Teacher observation occurs continually as a natural part of the learning and teaching process and can be used to gather a broad range of information about students’ demonstrations of learning outcomes’ (p. 16). Teacher observation has been valued as an important assessment technique in the lower primary school, but has in the past received less attention in later year levels. Secondary schools especially have favoured formal testing and structured assessment tasks rather than in-situ observation, although there has been some movement towards in-situ observation in some subjects in recent years, even in the senior years. The Council’s Position and Guidelines and syllabus documents elevate teacher observation to a more prominent position in the range of assessment techniques that teachers might use. Other techniques have been identified as consultation and focused analysis as well as peer and self-assessment. Focused analysis includes more formal assessment procedures such as set tests and set tasks. However, these categories of assessment techniques are not necessarily distinct. For example, as this paper explains, observation may be employed in association with focused analysis, especially where what is observed is student performance on a set task. This discussion paper is not an official policy statement of the Council. Rather, it represents the views of the author, Dr Graham Maxwell, of the School of Education, The University of Queensland. As such, it offers a personal perspective on the issues. Dr Maxwell has been involved in research and consultation on assessment for many years in Australia, USA and UK, ranging over all sectors and levels of education. He has taught courses and conducted workshops on assessment for pre-service and in-service teachers for 30 years. He has also been involved in recent Council deliberations on assessment and reporting. The audience for this discussion paper is professional educators, especially schoolteachers and administrators who must deal with assessment and reporting practice in classrooms and schools. Such people already know a great deal about assessment and reporting theories and practices, and this discussion paper builds on that knowledge. The hope is that the discussion paper will serve as a basis for professional debate, development workshops and collaborative planning. iii The Office of the Council would be pleased to have your reactions to and comments on the discussion paper, as well as any examples of ways in which the discussion paper may have helped to clarify or resolve any theoretical or practical problems you are facing in the implementation of Council syllabuses. These reactions, comments and examples would assist the Office of the Council in deciding what further assistance it might be able to provide on these issues. JE Tunstall Director Queensland School Curriculum Council October 2001 iv CONTENTS Preface Introduction Arguments for valuing teacher observation Collection and recording of evidence Planning for teacher observation Factors affecting validity of teacher observations and what to do about them 1. Prejudgments and prejudices 2. Selective perception 3. Providing inadvertent clues 4. Inappropriate inference 5. Inconsistency Conclusion Some useful references on teacher observation iii 1 2 5 7 9 10 11 11 12 12 13 14 v Teacher Observation in Student Assessment INTRODUCTION Teacher observation is one of the assessment techniques recommended in the Position and Guidelines on Assessment and Reporting for Years 1 to 10 of the Queensland School Curriculum Council (the Council). For the implementation of Council syllabuses, assessment is seen as involving a variety of school-based (teacher-enacted) techniques for profiling student demonstrations of learning outcomes. Teacher observation, that is, observation of a student by a teacher, is one of those techniques. It can be used in conjunction with other techniques. 1 Teacher observation has been accepted readily in the past as a legitimate source of information for recording and reporting student demonstrations of learning outcomes in early childhood education. As the student progresses to later years of schooling, less and less attention typically is given to teacher observation and more and more attention typically is given to formal assessment procedures involving required tests and tasks taken under explicit constraints of context and time. However, teacher observation is capable of providing substantial information on student demonstration of learning outcomes at all levels of education. For teacher observation to contribute to valid judgments concerning student learning outcomes, evidence needs to be gathered and recorded systematically. Systematic gathering and recording of evidence requires preparation and foresight. This does not necessarily mean that all aspects of the process of observation need to be anticipated but that the approach taken is deliberate rather than happenstance. It is necessary, at least, to know in advance both what kinds of learning outcomes are anticipated and how evidence will be recorded. Adequate records are essential for good assessment. Teacher observation can be characterised as two types: incidental and planned. †¢ Incidental observation occurs during the ongoing (deliberate) activities of teaching and learning and the interactions between teacher and students. In other words, an unplanned opportunity emerges, in the context of classroom activities, where the teacher observes some aspect of individual student learning. Whether incidental observation can be used as a basis for formal assessment and reporting may depend on the records that are kept. Planned observation involves deliberate planning of an opportunity for the teacher to observe specific learning outcomes. This planned opportunity may occur in the context of regular classroom activities or may occur through the setting of an assessment task (such as a practical or performance activity). 2 †¢ 1 2 Other possibilities for collecting evidence by observation exist, including observations by another teacher, observations by other students, and student self-observation. This paper concentrates on teacher observation and does not consider these additional forms of observation. Ultimately, the teacher must judge the validity and relevance of all forms of evidence, so these alternative forms of evidence involve similar principles of assessment to those applicable to other forms of evidence, including teacher observation. ‘Classroom’ should be interpreted liberally. It may include settings outside the school, such as field excursions, public presentations and work experience. What matters is the presence of an assessor, typically the teacher, to observe and record the event. 1 Discussion Paper on Assessment and Reporting ARGUMENTS FOR VALUING TEACHER OBSERVATION Teacher observation is an important but underutilised assessment technique. It is sometimes argued that teachers are unable to make appropriate and dependable assessment judgments from observations of students in natural settings. The table (below) details some of the claims of this viewpoint, together with some relevant rebuttals. Handled carefully, teacher observations can provide important evidence for assessment judgments. In some cases, they provide the only way of obtaining evidence about particular learning outcomes, especially those involving practical techniques, performance activities, ‘real life’ projects and group work. Table 1: Arguments against teacher observations and rebuttals of those arguments Arguments against teacher observations Lack of representativeness Students may not demonstrate all relevant learning outcomes in natural settings. They may know or know how but the context may not prompt them to demonstrate this. Lack of observation Teachers may not observe the demonstration of a learning outcome when it occurs, either because their attention is els ewhere or because they fail to recognise it. Lack of control of influences The student can derive unintended cues and prompts from the setting, even from the teacher, and these can be unnoticed by the teacher. Student performance may then be misinterpreted. Lack of standardisation All students do not undertake the same tasks under the same conditions. Teacher judgments of student demonstrations of learning outcomes are therefore undependable. Lack of objectivity Teacher judgments are subjective and prone to inconsistencies. Too much is left to the discretion of the teacher. Possibility of stereotyping Subjective judgments allow the possibility of stereotyping of students in terms of other performances or characteristics. Possibility of bias Subjective judgments allow the possibility of conscious or unconscious bias for or against particular individuals or groups. Rebuttal of those arguments Learning outcomes that have not been demonstrated can be deliberately prompted. Assessment should be planned as well as incidental. Teachers can ensure that assessment is comprehensive. Over time, teachers have many opportunities for observation. It is not critical if particular opportunities for observation are missed. Some observation is deliberate and focused. No single occasion is sufficient for judging a student’s demonstration of learning outcomes. Multiple opportunities and a variety of contexts allow cross-checking the robustness of the student’s performance. Quality requirements for teacher judgments are ‘evidence-based’ and ‘defensible’. Tailoring and adaptation allow optimum student performance and holistic interpretation of the evidence (taking contextual factors into consideration). All assessment involves sequences of subjective decisions; mechanistic marking schemes reflect earlier design decisions. Procedures to strengthen and verify teacher judgments can be introduced. Stereotyping is not inevitable. Each assessment occasion can be approached as a fresh opportunity to test hypotheses derived from prior impressions. Conscious bias is unethical. Unconscious bias requires constant vigilance. It is difficult for bias to survive evidence-based justification to students and their parents (a form of accountability). 2 Teacher Observation in Student Assessment An important argument in support of teacher observation is that teachers have access to a rich and diverse range of evidence on student learning outcomes from observations of their students; and that the capability of teachers to collect and interpret this range of evidence should be respected. Otherwise, a rich source of evidence on student learning outcomes is being ignored. In any case, the issue is not whether teacher observations should be used — since they are necessarily used informally during teaching — but how teacher judgments can be strengthened and improved so that they can be used for formal purposes, especially for reporting and certification. A strong justification for using teacher observation in assessment is its capacity to enhance assessment validity. By extending the range of possible assessments, teacher observation allows assessment to be more: †¢ †¢ †¢ †¢ †¢ comprehensive — ensuring recognition of all desired learning outcomes, especially those not otherwise assessable than in classroom contexts; connected — situated within familiar learning contexts and closely related to curriculum frameworks, learning experiences and pedagogical planning; contextualised — sensitive to the effects of context on performance and deriving assessment evidence from a variety of situations and occasions; authentic — interesting, challenging, worthwhile and meaningful to students; holistic — emphasising relatedness and connections in learning and involving performance on complex wholes rather than separate components. All of these characteristics can be supported as important for high quality learning and assessment. Assessments with these characteristics have better representation of, clearer relevance to, and stronger consequences for desirable learning outcomes. Appropriate representation, relevance and consequences are often now recognised as the requirements of valid assessments. Past practice in assessment, particularly in secondary schools, has not accorded much recognition to teacher observation for formal purposes. Some people have argued that while teacher observation is necessarily a component of classroom teaching, a clear distinction should be made between informal and formal assessment. For example, some educators argue that assessment situations should not be confused with learning activities. 3 This draws too firm a distinction. Certainly, there should not be strong accountability for first attempts. Also, reports need to indicate the progress made by students at the time of reporting. However, a firm  distinction between assessment situations and learning activities stems from over3 This is argued by Caroline Gipps in her book, Beyond Testing: Towards a Theory of Educational Assessment, The Falmer Press, London, 1994. 3 Discussion Paper on Assessment and Reporting concern for comparison and ranking. Where the aim is to map the student’s profile of demonstrated learning outcomes, standardised comparison is not the issue. The question is simply what justifiable evidence is there for concluding that the student has demonstrated a particular learning outcome. This does not require students to be ‘tested’ under controlled — and artificial — conditions. An alternative vision is one where assessment becomes incidental to and indistinguishable from learning activities. This allows for the strongest connection between pedagogy and assessment and, as already argued, a strengthening of the quality of the learning and the validity of the assessment. It can be argued that unless there is a strong connection between pedagogy and assessment, the assessment will be disembodied and discriminatory, that is, unconnected to any means for improving student learning and privileging students with existing cultural capital. Such an approach focuses on the student’s best performance over time and values the progress they are making (similar to ‘personal best’ in athletics). Howard Gardner puts it this way: ‘Rather than being imposed â€Å"externally† at odd times during the year, assessment ought to become part of the natural learning environment. As much as possible it should occur â€Å"on the fly†, as part of an individual’s natural engagement in a learning situation. Initially, the assessment would have to be introduced explicitly; but after a while, much assessment would occur naturally on the part of student and teacher, with little need for explicit recognition or labelling on anyone’s part. †¦ As assessment gradually becomes part of the landscape, it no longer needs to be set off from the rest of classroom activity. As in a good apprenticeship, the teachers and the students are always assessing. There is also no need to â€Å"teach for the assessment† because the assessment is ubiquitous; indeed, the need for formal tests might atrophy altogether. ’ 4 4 ‘Assessment in context: The alternative to standardized testing’, in B. R. Gifford M. C. O’Connor (Eds), Changing assessments: Alternative views of aptitude, achievement and instruction (pp. 78119), London, Kluwer, 1992. 4 Teacher Observation in Student Assessment COLLECTION AND RECORDING OF EVIDENCE All assessment requires the collection and recording of evidence of student learning. For the implementation of Council syllabuses, it has been recommended that the evidence focus on the demonstration of learning outcomes. Evidence is documentation that records, illustrates or confirms student demonstrations of learning outcomes. Collection and recording of evidence is necessary for two reasons: accountability — justification of the assessment judgments; and verification — confirmation of the assessment judgments. Accountability and verification are key factors in assuring the quality of assessments. †¢ †¢ Accountability (justification) means being able to explain and defend assessment judgments to students, their parent(s) and other teachers. Verification (confirmation) means being able to revisit the foundations for assessment judgments — being able to check their completeness, relevance and veracity. Teacher observations are primarily directed at the observation of events, performances and activities. In some cases, an artefact may be produced as a consequence of the event, performance or activity. In other cases, no artefact is produced and the event, performance or process iself is the sole focus of attention. An artefact is something constructed by the t student, for example, a worksheet, a piece of writing, a design, a painting, a composition, a webpage — in other words, a product of some kind. Teacher observation is not primarily concerned with the artefact itself but with the way in which the artefact was produced, that is, with the process. 5 Evidence of process, whether or not there is a resultant artefact, may involve either direct record or written record. These two types of record have different characteristics. A direct record keeps a ‘trace’ of the event through an audio-recording, a video-recording or a sequence of photographs. The activity or event might be, for example, a speech, a dramatic presentation, a group activity or a practical task. The term ‘trace’ emphasises that the record is not the same as the event itself. At best, it allows some features of the event to be represented and recalled. Some features of the event may be lost, such as the ‘feel’ of the occasion or the ‘spark’ between presenter and audience. Some features of the event may be filtered or distorted by the medium of recording, for example, through positioning and handling of the 5 In some cases, a sequence of artefacts may be produced and these may provide a progressive record of stages of production. These could involve, for example, a sequence of written drafts, initial designs, trial compositions, or tentative frameworks. In this case, the artefacts indicate milestones of development towards the final product. It is important to keep the total sequence of artefacts, together with annotations about contextual factors, such as the way in which the student has made use of comments and suggestions, so that a complete interpretation of what the student has done can be made. 5 Discussion Paper on Assessment and Reporting recording device. It is important, therefore, to realise that such a record offers only partial representation of the event. Nevertheless, such ‘traces’ are better than having no record at all. A written record can take the form of an observation sheet or a logbook (diary of events). Observation sheets can be more or less structured: at one extreme they contain checklists of learning outcomes; at the other extreme they contain broad categories for writing on-the-spot comments or annotations; and in between these extremes is a combination of them both. 6 A logbook provides a record of critical incidents or key comments (sometimes referred to as an anecdotal record); for accuracy of recall, entries need to be made as soon after the event as possible. The student’s name and the date also need to be clearly recorded. A sequential collection of such records is sometimes called a ‘running record’. When keeping an observation sheet or a logbook, written entries can be (relatively) high inference or (relatively) low inference. ‘High inference’ means that a judgment or interpretation is made, whereas ‘low inference’ means that the specifics of the event are described (without any attempt to interpret what they signify). Thus, using a checklist of core learning outcomes would involve high inference, whereas providing a descriptive account of student performance without direct reference to core learning outcomes could involve low inference. In the latter case, judgments relating to the demonstration of learning outcomes can be delayed until a variety of evidence has been collected. The advantage of low inference observations is that they are more ‘objective’ or ‘transparent’ and can provide a ‘closer-to-the-event’ basis for later verification; the specifics of the event are more easily accessible. The advantage of high inference observations is greater ease and efficiency in record keeping, but the specifics of the event are not then retrievable from the record. It is possible to record both a judgment (high inference) and a description (low inference), thus retaining some of the benefits of each. Descriptive accounts can include written commentary on student performance under specific headings on an observation sheet; critical incidents or significant events recorded in a logbook; and key performance features recorded in a logbook. Critical incidents and significant events are particularly noteworthy instances of the demonstration of particular learning outcomes (or the lack of it), especially those observed for the first time or demonstrated in a particularly dramatic or unexpected way. Key performance features are salient features of an observed performance whether or not they are particularly ‘critical’, including evidence that strengthens or confirms early judgments relating to student demonstrations of learning outcomes. When an artefact, direct record or descriptive account is kept and placed in the student’s assessment portfolio, the artefact, direct record or descriptive account can be referred to again at a later time in order to retrieve the specifics of student performance. This allows assessment judgments to be delayed until a convenient time or allows assessment judgments to be 6. Rating scales are not mentioned here since arbitrary distinctions of quality are not part of the assessment position espoused by the Council. However, the sequences of core learning outcomes (arranged in levels along a developmental continuum) provide quasi-rating scales. It is a matter of convenience and style whether a sequence of core learning outcomes is characterised as a quasi-rating scale (showing where the student is positioned along the developmental continuum) or simply an expanded checklist (showing which core learning outcomes the student has demonstrated). 6 Teacher Observation in Student Assessment verified on a subsequent occasion, for example, for purposes of moderation. It is difficult to verify written records of judgments without an accompanying artefact, direct record or descriptive account as a reference point. 7 Table 2: Summary of types of teacher observation evidence Focus on product — keep artefact(s) Focus on activity — record process †¢ Direct record (‘trace’) o Audio-tape o Video-tape o Photographs Written record o Observation sheet  § Checklist (high inference)  § Description (low inference) o Logbook  § Description of critical incidents  § Description of key performance features †¢ PLANNING FOR TEACHER OBSERVATION Teacher observations cannot be useful without planning. Different types of evidence require different types of planning. An essential requirement for  all types of evidence is anticipating the kinds of learning outcomes that may be demonstrated. This is particularly important where observation is incidental and where judgments (rather than descriptions) are recorded. Council syllabuses provide a framework of learning outcomes that serve as the perceptual reference points for recognising the characteristics of student performance. The framework of learning outcomes makes available to the teacher concepts and language for recognising and describing what a student knows and can do. Learning the structure, language and concepts of the framework therefore is a key aspect of planning for teacher observation, as it is too for teaching. Incidental observation necessarily involves little additional planning, apart from the normal planning of classroom learning activities for students. Incidental observation is opportunistic, 7 Where there is no supporting evidential record for the judgment, verification of the judgment is strictly impossible. The record of judgment needs to be considered in the context of other evidence collected from different times and events. Where it corroborates other evidence, the judgment is strengthened. Where it contradicts other evidence, more evidence may be needed. Ultimately, the weight of evidence is what matters. ‘Other evidence’ could include the judgments of other observers, that is, other records of judgment of the same event. 7 Discussion Paper on Assessment and Reporting  capitalising on revelations of student learning during regular classroom learning activities. In this sense it cannot be planned. It is essentially unanticipated. It can only be recorded through descriptions in a logbook. Although there may sometimes be an artefact to provide corroboration for the teacher’s observation, any process details depend on teacher description. Incidental observation is therefore the weakest form of teacher observation and would preferably be used only as supplementary evidence to support other forms o evidence. f Relying on incidental observation alone would be unsatisfactory (see caveats below). Planned observation can involve planning  for ‘in situ’ observation (in learning situations) or planning for set assessment tasks. There is little to distinguish these two situations in practical terms. However, as assessment becomes more important, particularly in Years 8 to 10, students may need to know when they are being assessed, since they may otherwise choose not to show their actual capabilities. Absence of demonstration of learning outcomes might not indicate incapability of demonstrating those learning outcomes but lack of appropriate challenge or opportunity. Formal assessment occasions would appear to become more important in the secondary school than in the primary school, at least for the present. 8 For all planned observations, whether ‘in situ’ or set tasks, thought needs to be given to how the event and/or the observations will be recorded. Consideration needs to be given to whether a direct record will be kept and what form of observation record will be made. The validity of teacher observations is strengthened by preparing an observation sheet that allows systematic recording of observations and judgments. An observation sheet may include checklists of learning outcomes and/or categories for describing student activities and performances. Learning outcomes might be made more explicit by listing their elaborations, components or criteria, that is, by providing more detail on the characteristics of the desired learning outcome. The advantages of prepared observation sheets include: †¢ †¢ †¢ †¢ †¢ †¢ †¢ †¢ opportunity to share learning expectations with students in advance encouragement of student self-monitoring and self-assessment clarification of the desired learning outcomes to guide learning focus on the desired learning outcomes to guide teaching cuing of attention to the full range of relevant learning outcomes having available an explicit and standard recording format ease of recording of student performance characteristics structured means of providing feedback to students. 8 In the long term, taking up Howard Gardner’s vision (see footnote 4), a more natural approach to assessment would require that classrooms become more like normal work environments. This does not necessarily mean that the student (as the worker) is under constant surveillance but that there are  opportunities to demonstrate their capabilities in situations that really matter (but are preferably ‘authentic’ rather than ‘artificial’). The necessary shift in assessment practice to support this is from ‘one-off testing’ to progressive demonstration of ‘best (sustained) performance’. Reformed assessment practice would place more onus on the student to demonstrate the desired learning outcomes (and to indicate when they think they are doing so) together with specific ‘invitations’ to students to demonstrate their level of development in relation to sequences of learning outcomes of increasing complexity. 8 Teacher Observation in Student Assessment  Disadvantages of prepared observation sheets include: †¢ †¢ †¢ †¢ the need to allow for several levels of learning outcomes on a single sheet it can be difficult to anticipate all the learning outcomes that might appear it is possible that other serendipitous learning outcomes will be missed students’ learning may be constrained by listed learning outcomes. The disadvantages are outweighed by the advantages. They can be overcome, in any case, by careful design of the observation sheet, tailoring it to the current stage of student development, and allowing space for additional observations to be recorded. Observation sheets should be used as a tentative organising structure for recording teacher observations rather than a limiting framework for the actual observations. Space also needs to be provided on the observation sheet for including descriptive details of the context. These details need to include any characteristics of the setting or the occasion that could have influenced the student’s performance, either positively or negatively, and that might be relevant in making a judgment about whether the student has demonstrated particular learning outcomes. The details can be physical (e. g. , uncomfortable surroundings), psychological (e. g. , personal attributes in stressful situations) or social (e. g. , other events in the life of the school or the student). Through all of this, it must be remembered that any written record  of observations is necessarily selective. Only certain features of student performance are likely to be noticed and can be recorded. Therefore, having a clear understanding and ready access to the framework of expected learning outcomes is essential. One technique for reducing the cognitive demands of open observation is ‘spotlighting’. This means targeting specific learning outcomes (across several levels of a strand) on particular occasions. This has the added advantage of ensuring systematic coverage of all relevant learning outcomes. However, it should not be pursued so religiously that evidence of other learning outcomes outside the spotlighting target is ignored. 9 FACTORS AFFECTING VALIDITY OF TEACHER OBSERVATIONS AND WHAT TO DO ABOUT THEM Teacher observations will be valid to the extent that the evidence is appropriately recorded and interpreted, that is, whether: †¢ †¢ the recorded evidence accurately represents the observed student performance the interpretation (judgment) of this evidence is justifiable. Accurate recording requires transparent and unbiased perception of the student’s performance. Justifiable interpretation requires careful consideration of what the student’s performance signifies, in terms of learning outcomes, taking into consideration any factors 9 Margaret Forster and Geoff Masters discuss ‘spotlighting’ in Performances: Assessment resource kit, Camberwell, Victoria, Australian Council for Educational Research, 1996. 9 Discussion Paper on Assessment and Reporting that may have influenced the performance. The use of the term ‘justifiable’ here emphasises that there may not be a single unequivocal interpretation of the evidence but rather that the interpretation should withstand challenge as being reasonable and defensible. There also may be a requirement that the interpretation be consistent with the interpretations of other teachers. 10 The following discussion covers some factors that can affect the accuracy of the recorded evidence or the justifiability of the interpretation or both.

Design of Interventional Biomedical Devices

Design of Interventional Biomedical Devices 1. Neurovascular Catheters and Engineering Design 1. Case Study 1. The following catheter found in the cathlabdigest written by Gill Laroya discusses the advancement of the design of interventional biomedical devices from an engineering perspective and how engineers enhance the design of catheters to prevent problems such as kink. The article discusses areas such as the history of biomedical devices, the materials involved, design challenges and the interface. It discusses a specific example in terms of catheters and their use. If a catheter must travel a long distance within the neurovascular anatomy, the engineer designing the product might decide to incorporate a shaft support component, such as a stainless steel braid in order to enhance the micro catheters kink resistance. The down side of incorporating the stainless steel braid is its ability to travel within tight sections and irregular shaped bends within the neurovascular system. In order to solve this problem a stainless steel coil support is added to the distal end of the catheter, the ad dition of the coil support enhances lateral flexibility and adding hoop strength to even better the kink resistance of the micro catheter. Also, the engineer can add a lubricous hydrophilic coating to the catheter to improve axial and rotational handling of the device and reduce trauma on the walls of the veins and arteries. The study shows us how we can design micro catheters to prevent problems such as kink occurring. Cathlabdigest.com. (2016). The Design of Interventional Devices: An Engineers Perspective | Cath Lab Digest. 2. Neurovascular Catheter Design The following article was posted in Medical Tubing Types by Shana Leonard on December 12, 2014. Form the article it is predicted that by 2020 the neurovascular market will reach $600 million, according to iData Research. A key factor contributing to the growth of this sector is down to the various advancements of the biomedical device. The design goal for minimally invasive surgical devices is to strive towards engineering the smallest possible outside diameter for a micro catheter device without compromising any of the performance characteristics. Designing neurovascular catheters to meet these constraints must take into account the intricate neurovascular anatomy. Mddionline.com. (2016). Key Considerations for Designing Neurovascular Microcatheters | MDDI Medical Device and Diagnostic Industry News Products and Suppliers. According to Steven W. Berhow, president of Rogers, MN-based Biomerics Advanced Catheter, he believes that upon designing neurovascular catheters they must contain the following traits; Good torque within the shaft from the proximal to distal end. Flexibility in the distal portion of the catheter. Kink Resistance. Visibility under fluoroscopy. Low Stretch. High Pressure. Good guidewire movement. These 7 traits stand as basic constraints when it comes to designing intricate, complicated neurovascular minimally invasive devices. Figure 2. Neurovascular Catheter Design.   Mddionline.com. (2016). Key Considerations for Designing Neurovascular Microcatheters | MDDI Medical Device and Diagnostic Industry News Products and Suppliers. 3. Advanced Catheters The first thing you need to know is what an advanced catheter is. So according to Bill Alexander, Director of Business Development at Biomerics Advanced Catheter, an advanced catheter is a minimally invasive medical device that typically consists of a thin walled, braid reinforced tube or shaft with multiple durometers. An advanced catheter has the ability to navigate through the neurovascular anatomy and deliver implants and devices such as coils, heart stents etc. The difference between advanced catheters and traditional catheters can be mainly seen when it comes to manufacturing the product. A little error in the materials used in an advanced catheter can lead to larger errors as the specific wall thickness requirement of an advance catheter are very strict to ensure optimal performance. Characteristics such as pushability, trackability, torqueability and kink resistance are crucial for the advanced catheter design. Traditional catheters and advanced catheters are not mutually exclusive and can be used to benefit each other and improve patient surgical results. (2016). Advanced catheters What you need to know about this growing medical device market. Figure 3 Advanced Catheters and Traditional Catheters.   (2016). Advanced catheters What you need to know about this growing medical device market. Advanced catheters have the ability to incorporate new technologies and have a more complex design than traditional catheters. 2. Human Neurovascular and Cardiovascular Anatomy 1. Cardiovascular System The cardiovascular system consists of the heart and blood vessels along with blood itself. It transports oxygen, nutrients, hormones and more and is powered by the heart. The heart consists of 2 circulatory loops, the pulmonary circulation loop and the systematic circulation loop. The pulmonary circulation transports deoxygenated blood from the right atrium and ventricle to the lungs. The systematic circulation carries oxygenated blood from the left atrium and left ventricle to all around the body. The cardiovascular system consists of blood vessels, coronary circulation (hearts own set of blood vessels), hepatic portal circulation (veins of stomach and intestines) and the blood itself (red blood cells, white blood cells, platelets and plasma). An understanding of the complex network and its physical structures are important when designing non-invasive medical devices. System, C. (2016). Cardiovascular System. InnerBody.   Figure 4 Cardiovascular System. Slideshare.net. (2016). Circulatory system PowerPoint Blood vessels are the road network by which blood transports around the body and returns back to the heart again. This intricate tiny transportation system of blood vessels has a major part to play when engineering advanced catheters and ensuring problems such as kinking dont occur. 2. Structure and Functions of Blood Vessels Blood vessels consist of arteries and veins. Arteries bring blood away from the heart. As the arteries are brought away from the heart they eventually become smaller and are broken down to the smallest arteries called arterioles which further branch into capillaries where gases and nutrients are excreted or exchanged. Veins have a larger structure and bring blood back to the heart again. As can be seen below in figure 4, the cardiovascular circuit can be seen where two main circulatory systems occur. The pulmonary circulatory system and systematic circulatory system. Each providing their own different structural differences that engineers must take into account when designing minimally invasive medical devices. Philschatz.com. (2016). Structure and Function of Blood Vessels  · Anatomy and Physiology. Figure 5 Structure of Blood Vessels. ] Philschatz.com. (2016). The structure of blood vessels can be seen below. The artery and the veins vary in thickness as can be seen from the micrograph in figure 6. From figure 5, it can be seen that Arteries have a thicker Tunica media than Veins but veins have a larger tunica externa than arteries. Figure 6 Arteries vs Veins Structural differences. Philschatz.com. (2016).  Ã‚   Figure 7 Micrograph showing the relevant difference in thickness. Philschatz.com. (2016). As can be seen in figure 6 and 5, vein walls are considerably thinner than Artery walls meaning veins withstand a much lower pressure of blood passing through them. Table 1 Appearance of Arteries and Veins. Philschatz.com. (2016). Arteries Veins General Appearance Thick walls, small lumen Rounded appearance Thin walls, large lumen Flattened appearance Conor Patrick Goold, DME4. 7 3. Shapes of Catheters in the Neurovascular Anatomy 1. Guide Catheters and shapes in the Neurovascular system. The following is an example of a Stryker neurovascular catheter called the DAC catheter. From figure 8, it can be seen that the DAC catheter accesses the distal neurovasculature. It achieves this by providing enhanced stability through a braided shaft and this in turn also provides resistance to ovulation. Preventing shapes such as snaking and reducing friction against the blood vessel walls. Stryker.com. (2016). Neurovascular Intervention DACâ„ ¢ Catheter: Stryker. Figure 8 Catheters, Shapes and Uses. Stryker.com. (2016). Neurovascular Intervention DACâ„ ¢ Catheter: Stryker. 2. Neurovascular Catheters in the Brain. The following images are obtained through a technique that requires the use of a minimally invasive advanced neurovascular catheter. What these images do is they give a visual understanding of the intricate nature in which the catheters must travel within the cardio vascular system. To do this the catheter is guided under x-ray guidance through neurovascular and cardiovascular system. The catheter for this procedure is usually brought to a blood vessel located in the neck and a non-ionic x-ray contrast agent is injected into the blood vessels which then in turn travels through to the brain. Prior to this procedure the catheter is then removed through the groin and the bleeding is stopped through direct manual compression or by using a vascular closure device. Neuroangio.org. (2016). Introductory Brain Angiography | neuroangio.org. Figure 9 ICA Internal Carotid Artery. Neuroangio.org. (2016). Introductory Brain Angiography | neuroangio.org. In order to reach such distances in the neurovascular system, many advanced catheters are used to travel so far. The deployment of a large support catheter through the groin goes first and then a variation of other smaller catheters are deployed through the larger catheter in order to reach the required location and deploy medical devices such as coils and stents. Figure 10. CT scan of Brain. Neuroangio.org. (2016). Introductory Brain Angiography | neuroangio.org. 3. Neurovascular Catheters in the heart. Figure 11 shows the placement of a pacemaker into the heart by the deployment from a minimally invasive advanced catheter. The catheter enters the body through the collar bone on the left hand side of the heart and enters through the veins to place an electronic or mechanical pacemaker into the heart to overcome heart problems such as tachyarrhythmias, which occurs when your heart beats too fast or bradyarrhythmias, which occurs when your heart beats too slow. System, C. (2016). Cardiovascular System. Figure 11 Advanced Catheters in the Heart. System, C. (2016). Cardiovascular System. From figure 11, the C shaped position of the catheter can be seen. A number of issues can occur from an engineering perspective when a catheter must bend into the shape of a C. Kinking can occur at the maximum area of stress and strain. Engineers must design their advanced catheters in order to prevent kink from occurring and so a reinforcement braid is usually added to increase the hoop stresses of the catheter and the addition of this braid also provides better torqueability and pushability of the medical delivery device to allow it to bend to the required positions to deploy a pacemaker in the heart. 4. Research into Existing Test Methods 1. Simple existing Test methods The following is the most basic of test methods implemented by physicians when no Standard test method is available and time is of the essence. This method was applied when surgeons were experiences kinking in catheters when deployed into patients. In order to predetermine kink from happening the physicians used a simple bending technique to test for the kinking limit of catheters. If the catheter kinked, the unit was rendered useless, if not it was determined safe to use. This method is clearly not an optimal solution so further investigation into the kinking limit of catheters had to be researched and developed. Beamer, J. and French, G. (2016). A simple method for testing for the kinking epidural catheter. Figure 12 Simple Test Method No kink LHS and Kinked RHS. Beamer, J. and French, G. (2016). A simple method for testing for the kinking epidural catheter. 1.1 Simple existing test methods The catheter bends around the pin, having a predetermined diameter, D. The diameter can range from a number of different values, 5mm 50mm. The catheter is bent around the template and contacts the template at 2 tangential locations, to generate a curve and predetermine L = D. Figure 13 Kink resistance Test Method. Anon, (2016). 2. Guidance for Industry and FDA Staff Non-Clinical Engineering Tests and Recommended Labelling for Intravascular Stents and Associated Delivery Systems The following FDA guidelines outline the standards to abide by when dealing with stents and associated delivery systems. It details how the content and format of test data should be summarised in a report as well as detailing the test reports and test protocol procedures to carry out. For this test method, a review of the non-clinical engineering section was undertaken focusing on the section B (Stent Dimensions and Functional attributes) of the non-clinical engineering test, part 16. Part 16 gave FDA guidelines in kink resistance. The significance of outlining FDA guidelines for stents which are delivered by advanced catheters, it to prevent kink occurring when the normal body is in motion such as an elbow joint flexing and to ensure that no deformation to the stent occurs. This also applied to the stent delivery system when the physician deploying the stent into the human anatomy as the advanced catheter must be engineered to prevent kink from occurring upon deployment. The recommended outcome to prevent kink from happening, according to the FDA guidance document, is to determine the smallest radius of curvature that the stent can withstand and recover to its original shape and size. The test carried out to determine the smallest radius of curvature must replicate the area to which the stent will be deployed i.e. the femoral arteries. This recommended advice for implementing stents to the human body can be tailored towards the stent delivery systems also i.e. the advanced catheters. Therefore these guidelines will be taken into account when developing a test method to determine the kinking limit of catheters. See appendices for further detail regarding the FDA guidance documents discussed. Fda.gov. (2016). Guidance for Industry and FDA Staff Non-Clinical Engineering Tests and Recommended Labeling for Intravascular Stents and Associated Delivery Systems. 3. Standards and guidelines ProtomedLabs provide a list of standards and regulations that relate to flexibility and kink resistance test methods. Information on the state of the art available testing equipment is provided such as the interventional device testing equipment (IDTE) from MSI which will be discussed further in part 4 of this section (MSI Catheter testing equipment). The ProtomedLabs provide information on flexibility kink resistance regarding applicable standards, related tests and test method descriptions. Applicable standards such as the FDA guidelines discussed in heading 2 above as well as ASTM standard guide for three point bending of balloon expandable vascular stents and stent systems which will be further discussed in section 5 of the literature review. Protomedlabs.com. (2016). Flexibility Kink Resistance Protomed Labs. 4. MSI Catheter testing equipment State of the art interventional device testing equipment (IDTE), compares tests and analyses performance catheters, quantifying the data of each catheter being tested. The PC allows for simple and repeatable tests with instantaneous feedback on design changes of the catheter. The IDTE was designed taking into account several different standards and test regulations such as ISO standard 25539-1 which covers cardiovascular implants endovascular devices and ISO 15539 Cardiovascular implants Endovascular Prostheses. The product is the most state of the art catheter testing equipment available right now and differentiates itself from the rest of the market by having the ability to test catheters in extremely realistic and challenging conditions. MSI. (2016). Catheter Testing MSI. Figure 14. IDTE Test Equipment. MSI. (2016). Catheter Testing MSI. The IDTE has a high temperature range with ambient temperatures of 50oC, a water bath with a temperature accuracy of +/- 2oC. It has auxiliary load cells of 100g and distal load cells of 1kg. It has the ability to test track force which is the force needed to advance a catheter, push efficiency which measures the amount of force being measured from the proximal end to the distal end, flexibility, torqueability a measure of the rotational response, retractability a measure of the amount of force required to withdraw a catheter and the crossability which measures the ability of a catheter to cross the abnormal narrowing of a passage in the body. The machine itself weighs 250kg with a height of 1372mm, width of 1194mm and a depth of 940mm. the output data of each tested is outputted onto a computer where numerical or graphical results can be formulated. MSI. (2016). Catheter Testing MSI. 5. Current Test Methods available to determine Kinking Point 1. ASTM F2606 Standard guide for three-point bending of balloon expandable vascular stents and stent systems The three point bending of stent system guidelines provide a test method that can be used to compare the flexibility of different advanced catheters by comparing load deflection curves and by comparison of calculated slopes of the curves. The test method uses a simple 3 point bending test. The upper single load applier and the two static load supporters as seen below in figure 14 must have a radius of 6.35mm. Another requirement of this test is that both the upper load applier and the two bottom static load supporters must be made of a material with a low friction coefficient so that they do contribute to the results outputted from carrying out this experiment. This test method can also be carried out in a bath of 37oC, which replicates the ambient body temperature and realistic conditions, if this application is necessary, the fixtures can be made from stainless steel or other materials that will not rust. Figure 15 Example of a three point bending test. YouTube. (2017). Catheter Bend Test at Anecto. This test has many benefits as it can many advanced catheters can be used with this method and it is applicable to many different products. It does not cause damage to the product prior to testing and can test the kinking limit along different material junctions. The test method ASTM F2606 uses a tensile tester to output its results to a computer in numerical or graphical form. Instron.us. (2017). ASTM F2606 Three-Point Bending Balloon Expandable Vascular Stents and Stent Systems Instron. 3. BS EN 13868 Catheters test methods for kinking of single lumen catheters and medical tubing This standard test method looks at the kinking of catheters being used for short term or long term uses. The short term use determines the kinking limit of a catheter being used less in than an hour and the long term is above an hour. The tube is defined as being kinked when the flow meter (Labelled 4 in figure 15 below) is outputting a reading 50% lower than the original reading. The original reading is read when the kink tools (Labelled 7) are either 50mm, 100mm or 200mm apart, depending on the users required starting distance. When the kinking tools are being compressed by the tensile tester (Labelled 7) the mass flow rate of the water flowing from the beakers (Labelled 2) will begin to reduce. Once the mass flow rate reduces to 50% of its original the catheter is said to be kinked and the test is complete. The results are outputted to a computer which gives numerical and graphical results. This test method is very beneficial as it is convenient, safe and fit for purpose. Difficulties may arise when using this test method when it comes to the fittings of the flow meter with the different sized catheters. As all catheters vary in sizes, the universal fitting of the flow meter may be difficult to mate with the distal/proximal ends of the various advanced catheters. See Appendices for more detail regarding BS EN 13868 kinking of single lumen catheters. European Standard, (2002). Catheters Test methods for kinking of single lumen catheters and medical tubing. BS EN 13868:2002. Figure 16 Short Term (LHS) and Long Term (RHS) Test methods for kinking single lumen catheters and medical tubings European Standard, (2002). Catheters Test methods for kinking of single lumen catheters and medical tubing. BS EN 13868:2002. 6. Proposed Mathematical Methods for Determining Optimal Test Method significant factors. 1. Analysis of Variance (ANOVA) Testing. The analysis of variance method determines if groups (related or unrelated) are statistically significant to each other. In order to carry out an ANOVA test, a hypothesis must first be determined. A hypothesis is a standard procedure about testing a claim about a property of a population. First a null hypothesis is formed. The Null hypothesis will test the significance of the hypothesis by either rejecting or failing to reject the claim of the null hypothesis. The Null hypothesis will claim that no difference exist between the population and the alternative hypothesis will claim that a difference exists between the populations. The alternative hypothesis will state that one or more of the parameters involved in a population will differ from the null hypothesis. The next step in an ANOVA test is to determine if the null hypothesis should be rejected or is it better to fail to reject the null hypothesis. In order to do so, an understanding of a type 1 and type 2 error is needed. A type 1 error is when the null hypothesis is rejected when in fact it should be accepted. The symbol ÃŽ ± is used to represent a type 1 error. A type 2 error is the mistake of failing to reject the null hypothesis when in fact it is false. The symbol to represent a type 2 error is ÃŽ ². In order to determine when the results are statistically significand and when the null hypothesis should be rejected, then p < ÃŽ ±, therefore the result is statistically significant and the null hypothesis should be rejected. If p > ÃŽ ±, then the null hypothesis should fail to be rejected and the results are statistically insignificant. Lacey, S. (2017). Mathematics for Engineers 402. 2. Analysis of Variance (ANOVA) Examples. To show how the ANOVA method can be applied to the parameters involved in determining the kinking limit of catheters and which factors attribute to the kinking limit the most i.e. which are statistically significant or insignificant, an example where an experiment was undertaken to test the effect of temperature and bar size on the UTS of a weld. The results from the experiment are show below in figure 16 and analysis of variance was carried out in order to determine the level of significance each parameter had on the strength of a weld. Lacey, S. (2017). Mathematics for Engineers 402. Figure 17 Analysis of Variance Example Dr. Sean Lacey, 2016, Mathematics for Engineers 402. Figure 18 Analysis of Variance Example Dr. Sean Lacey, 2016, Mathematics for Engineers 402. Figure 19 Analysis of Variance Example Dr. Sean Lacey, 2016, Mathematics for Engineers 402. Figure 20 Analysis of Variance Example Dr. Sean Lacey, 2016, Mathematics for Engineers 402. 7. Material Properties of Neurovascular Catheters Advanced catheters are engineered to perform an increasing number of minimally invasive surgeries. They must be able to guide their way through the intricate pathways of the neurovascular, cardiovascular and other anatomies. In order to achieve these demands, using ultra small catheters of 0.5 mm, the design must be near perfect and material selection for this design is key. Catheters consists mainly of 3 layers, the liner, the braiding and the outer sheath. They can be made up to lengths ranging from 900mm 1200 mm. the best material for use in catheters are fluoropolymers such as PTFE and FEP due to their biocompatibility and lubricous properties. PTFE is the most lubricous polymer on the market today followed by FEP. The materials can undergo secondary processing steps such as etching and cutting, along with post extrusion expansion such as heat-shrinking. The liner layer mainly is made from PTFE for it lubricity, ability to maintain a thin wall and have a small diameter. The braid reinforcement layer is mainly made from Type 304 or 306 stainless steel. This layer increase is strength and rigidity without kinking the catheter. It increases the rigidity at the proximal end with a smaller pitch between winds and decrease rigidity at the distal end with a larger pitch between winds. This is done to provide greater torque transition from the proximal to distal tip of the catheter. The coil provides a greater kink resistance to the catheter along with reinforcing the catheters liner against ovalization by maximising the hoop stress. The outer sheath is made up of high performance materials such as Pebax, FEP, PTFE, ETFE, polyurethane, polyethylene and nylon. Mddionline.com. (2016). Think Extrusion and Beyond for Optimal Catheter Design | MDDI Medical Device and Diagnostic Industry News Products and Suppliers. Figure 21 Material layers of a Neurovascular Catheter. Mddionline.com. (2016). Think Extrusion and Beyond for Optimal Catheter Design | MDDI Medical Device and Diagnostic Industry News Products and Suppliers.

The Effect of Walking on Blood Pressure Essay -- Health, Diseases

The Effect of Walking on Blood Pressure Walking is one of the oldest means of transport known to mankind as well as a more physical activity undertaken by the majority of people in their lives. Walking has become an interest field for researchers, where there is evidence to show how walking can help in the prevention and treatment of many chronic diseases, such as cardiovascular disease, diabetes, renal diseases, hypertension, breast cancer, colon cancer, depression, stress and obesity. It has also become a major recommendation of the American College of Sports Medicine (ACSM) and the Center of Disease Control (CDC). It is suggested that brisk walking for 30 minutes, 5 days a week, at 3-4 miles per hour for adults is a form of moderate intensity physical activity which can prove effective as a useful prevention and treatment model (Lee and Buchner, 2008). Many studies have provided evidence that walking is an effective approach for decreasing blood pressure in both hypertensive and normotensive, and that there is an inverse relation between them (Kelley et al, 2001). A recent systematic review, which involved 27 randomized controlled trials, showed a reduction in either systolic/diastolic blood pressure, or both, in response to a walking programme. This reduction was significantly statistically shown in 9 trials. Of these 9 trials, three studies reported that the decrease was significant for both systolic and diastolic blood pressure, four showed a significant decrease only in systolic blood pressure, while two studies found a significant reduction in diastolic blood pressure. The mean difference between walking groups and control groups was found to range from -5.2 to -11 mmHg for systolic blood pressure, while for diastolic ... ...s too long, participants may be unwilling to follow or complete it. Thus, it has been found that a walking programme which is more than 12 months long is less effective than a 6 month programme, and that the explanation for this is due to a decrease in the participants’ adherence to the programme (see Lee et al, 2010). It seems that the longer the programme, the less likely it is that the individual will keep to it. It was found (by Lee et al, 2010) that the way in which the time spent walking each day was divided up made no significant difference in terms of reduction of blood pressure response. The study measured the effect of walking on blood pressure by dividing the daily session of walking into three short bouts of 10 minutes; and it was found that this had the same effect on blood pressure as a continuous uninterrupted daily walking session of 30 minutes.