A Paper in Support of the Progressive Creationism Theory Research

A in Support of the Progressive Creationism Theory - Research Paper Example This particular theory is neither purely scientific or atheistic such as the atheistic evolution theory, nor purely biblical like the theistic evolution or 24-hour day theory. It aims to mediate these two frames of thought by explaining creation in a way that addresses the concerns of both though patterns. According to Dale Tooley in his paper, â€Å"Progressive Creation: An Overview†, the progressive creationism theory is increasingly becoming accepted as a viable and arguable theory for the creation and origin of the world. In contrast to young earth creation theories, it maintains that the 6 days of creation written in the bible do not necessarily refer to 24-hour days, but instead refer to â€Å"ages†. This gives way to hard scientific evidence regarding the earth's age. Some may discard this theory due to some wordings in the bible that refer to actual days, however, we must keep in mind that we cannot compare God's day with our own. As Christians recognize that Go d's knowledge is infinite and encompasses and eclipses our own, we cannot compare his understanding to ours. This is supported by the bible in the book of Mathew, 24:36. â€Å"No one knows about that day or hour, not even the angels in heaven, nor the sun, but only the father.† This particular area of the theory also allows for intraevolution, or evolution and development within a species, but does not recognize interevolution, or evolution into other species. This gives us an explanation or rationalization for the 6 day-ages of creation. Some other theories will discount this theory saying that the bible states that death is a result of sin, and therefore, would mean that there was no death for ages until Adam committed the first sin. This can be answered in a very simple statement. Man is a very unique creation. We are not just a higher form of animal but instead were created in God's image. We were given higher thinking, rationalization, and a sense of right and wrong. The refore, the weight or burden of sin only applies to us. Since animals do not have a moral compass, and are not accountable to God, we are the only creatures that are affected by sin. Therefore, death came to us as a result of our sin and disobedience, not because of anyone else. Also discussing humans as unique creatures, we must touch on the subject of evolution. We were presented with a theory concerning man's evolution from primates. Most, if not all Christians will not accept this,and for good reason. It is not about not wanting to be associated with monkeys, nor about denial of evolution, but about how the creation of man was described in the bible. If we look at it, creation of other creatures was described rather normally. There were not a lot of details that were given regarding how other creatures were created, but this is not the case with man. The bible gave details on how man was made. This indicates that our creation is unique, purposeful and special. The bible also des cribes that we were made in God's image and that life was breathed into us by God himself. This highlights just how special we are. The theory does recognize that within ages, animals can evolve and adapt, with the guidance of God. A good example of this is the abundance of different kinds of birds. Some swim, others walk, others fly. But never the less, all of them are still birds. This is not the same as the evolution of man from primates. We are not

Main Pollutants emitted by vehicle Engines Essay Example for Free

Main Pollutants emitted by vehicle Engines Essay The hydroxyl radical then reacts with nitrogen dioxide and oxidises it to nitrate ions. The superoxide ion reacts with nitrogen monoxide to form nitrate ions. NO2 + OH H+ + NO3- NO + O2- NO3- These nitrates are then either washed away or absorbed by the blocks to form stable compounds. The crystals also catalyse the reaction because the surface of the block holds together the reactants. This increases the concentration of the reactants. Figure 2: NOX removal by titanium oxide crystals. x Three-way Catalytic Converters A three-way catalytic converter oxidises carbon monoxide and hydrocarbons, and reduces the levels of nitrogen oxides. It does this by creating the right conditions for reactions of these emissions to occur. The air to fuel ratio must be carefully controlled as oxygen is needed for the reaction of carbon monoxide and hydrocarbons. Oxygen sensors are fitted in engines with a three-way catalyst. Figure 3: The three-way catalyst system. xi Three-way catalysts are designed to produce more desirable reactions and less undesirable reactions. Desirable reactions reduce the harmful emissions from the car exhaust. Carbon monoxide and hydrocarbons react with oxygen to produce carbon dioxide and water, and nitrogen oxides react with carbon monoxide to produce carbon dioxide and nitrogen. The products are already present in the Earths atmosphere. 2CO + O2 2CO2 C7H16 + 11O2 8H2O + 7CO2 2CO + 2NO 2CO2 + N2 xii Three-way catalytic converters contain the stoichiometric fuel mixture. This means that the catalysts have the right amount of oxygen to combust the fuel and react with the carbon monoxide and hydrocarbons. Three-way catalysts also contain ceria, which stores oxygen when the mixture is lean, and releases it when the mixture is rich. This gives optimum conversion of pollutants because as the carbon monoxide and hydrocarbons are absorbed onto the catalysts surface, the oxygen stored by the ceria oxidises them even if there is not enough oxygen in the air to fuel ratio. xiii The future Scientists still have problems that need to be solved to reduce harmful vehicle emissions. One problem that needs to be addressed is how to prevent harmful exhaust emissions when the catalyst is still warming up. There are several ways that this could be dealt with, including operating the catalysts at lower temperatures and also heating the catalyst before the engine is started. xiv Scientists also need to develop a system that is able to reduce nitrogen oxide emissions from diesel engines. There are several ideas on how to go about this, including using ammonia in the exhaust, but nothing has yet been developed.  http://www.nutramed.com/environment/carsepa.htm

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.

Time For A Change :: Essays Papers

Time For A Change The more that I learn about fossil fuels and their effect on the environment, the more surprised I become about the state of the world we live in. It seems that we live in a time that demands instant gratification. The problem with instant gratification is that the repercussions are seldom thought about. While millions of people think nothing of driving their cars for hours a day, the effects of decades of this behavior are already manifesting themselves around the world. This is particularly true in the United States, where mass consumption of fossil fuels are propagating serious environmental hazards. Perhaps the problem that strikes me as most frightening is the problem of acid rain. The nitrogens and sulfides in fossil fuels that we burn are wrecking serious havoc on the air we breathe. It is horrifying for me to think of rain falling that contains extremely corrosive and damaging factors. If this rain has the ability to corrode buildings, monuments and stat ues, I can only imagine how its long term effects must damage organic matter (Acid Rain, March 2005). It is also difficult to predict the future of this state. Will the problem intensify with time or will the recent slew of clear air acts and proposals have a palpable effect on the air we breathe? Have we passed the point of irreversibility or can we ameliorate the problems that have building over the last decades in the golden age of fossil fuels? Despite the looming problems at hand, I can’t help but feel optimistic about the situation. Technology has gotten us into this problem, and it could very well get us out of it. One breakthrough in technology could easily reduce the incidence of pollution in the long run. With the emergence and surprising popularity of hybrid cars (Hybrid Cars, March 2005) and all the research into alternative fuels such as hydrogen, it seems that the only thing missing is the technology itself. The market is clearly there. Hybrid cars have sold an astounding already. Also, considering the unprecedented exponential rate of technological advance in the past 100 years, it seems almost inevitable that a breakthrough is just around the corner.

Dance Elements Essay

Literal meaning of the word kathak is related to katha, the art of story-telling, â€Å"Katha Kahe So Kathaka Kahave†, which means â€Å"one who tells a story is a story-teller†. According to M. Monier Williams, Katha denotes conversation, story, speech, tale or fable. Katha also means to ‘ sing in praise’, ‘to say or inform something’. Thus, kathakars were originally a caste of story-tellers who were attached to temples in certain parts of Northern India. These kathakars used to go around the countryside narrating the stories of the Epics and other Legends. The modes employed were poetry, music and dance. All these three arts were closely inter-linked. The aim of kathaks was to educate the people in the knowledge of Gods and Mythological Legends. Historically kathak dates back to the Vedic period which are full of descriptions and stories which give us an insight into the mind of those who wrote or composed jthem. Kathak dance is evolved from religious and mythological concepts. In Ramayana period, we can see many glimpses of music and dance. The Ramayana tells the story of an ideal heroic prince Rama of Ayodhya and his devoted wife Sita. This ancient tale has been treasured and retold for countless generation in every Hindu house; they worshipped Rama as the seventh incarnation of Lord Vishnu. In Ramayana we find a mention of recitors who were specialised in story-telling. Lava and Kusha, the two brave sons of Rama rendered Ramayana in verses composed by Sage Valmiki. While reciting the stories, they also added the element of acting-Abhinaya. From that time nomadic bards who narrated the Ramayana were known as ‘Kushilavas’. As a matter of fact, the term kushilavas has been associated with dancers and actors. Likewise, many mythological stories were depicted through gestures, postures and abhinaya. The another story of Ramayana which tells us that how Ravana, the king of Lanka worshipped Lord Shiva with song and dance. Also the story of Ravana assaulting Rambha, one of the main Apsaras. According to Kapila Vatsyayan, in Ramayana, the Apsaras are the most important mythological characters who danced and performed both in heaven and earth. There are various other instances like the stories of the grand act of breaking Shiva’s bow in â€Å"Sita Swayamvar†, the evil plotting of Kaikayee, the Banishment of Rama to a fourteen-year exile, Sita’s kidnapping by Ravana and the war that ensued leading to Rama’s victory and Sita’s rescue. Thus, Ramayana is rich in incident and moral concept. We come across many references to perfomances of dances from the Mahabharata. In this period, worship and adoration of Bramha, Vishnu and Mahesh started with music and dance. Krishna is the ‘Sutradhara’ (around whom the entire Mahabharata developed) and he was an expert dancer. The Mahabharata depicts episodes of Krishna’s life that how he is adopted and raised by a family of cowherds. The stories of his childhood of stealing butter and milkmaids known as â€Å"MakhanChori†. His dance of his youth with Radha and Braj narees is known as â€Å"Rasa Lila†. His spiritual love dance with Gopis or Milkmaids by the bank of Yamuna river in moonlit night is known as â€Å"MahaRaas†. The story of â€Å"Kaliya Daman† which tells us how Krishna defeated the poisonous snake Kaliya and danced on his hoods. The story of â€Å"Govardhan Dharan† which tells us how krishna picked and hold the Govardhan mountain to protect the people of Vrindavan from heavy rain. Another important episode of Mahabharata is known as â€Å"Vastraharan†, in which Krishna saves the honour of the Pandava Queen Draupadi. The story goes that Dushasana, one of the Kaurava brothers attempted to humilate her by disrobing her. Draupadi called out to Krishna to save her and miraculously, as layer after layer of her saree was pulled, the number of sarees went on increasing. This episode is a popular theme in Kathak dance. Mahabharata also depicts the story of the five Pandava brothers who were unjustly deprived of their kingdom by their cousins, the kauravas, and of the great battle of Kurukshetra that established the victory of the Pandavas after much suffering and bloodshed. The Mahabharata also describes Krishna’s role as the Charioteer of Arjuna during the battle of Kurukshetra, and his conversation on the battlefield constitutes the text of the Bhagavad-Gita, the celebrated philosophical work. Thus, it is clear that by the time of Mahabharata, the arts of music and dance developed sufficient content, form, style to be taught in a systematic order. The training also seems to be elaborate with rules and regulations. Natyashastra is an encyclopedic work having 36 chapters and it deals with various topics such as the first 3 chapters deal with the origin of Natya, construction of theatre, Rangapooja, etc. , 4th and 5th chapters deal with the varieties of Dance. The 6th and 7th deal with Rasa and Bhava. From the 8th chapter of the 15th one, the different poses of Dance are being dealt with. The different aspects of Abhinaya are described in 15 to 22 and from 22nd to 28th describe the costumes elaborately. The chapters from 28th to 34 deal with music and musical instruments and the last two deal with the different characters and costumes. Natyashastra also describes the divine character and dance of the Nataraja, the dancing Lord Shiva who is considered the king of actors and dancers and also the supreme Lord of Dance. The moon which he adorns in his head is the symbol complete control of his senses. The serpents wound around his body is the proof of his complete control over vital life forces. His foot raised high over the wicked demon, a symbol of victory over the ego. This divine art form is performed by Shiva and his wife Goddess Parvati. The Dance performed Lord Shiva is known as â€Å"Tandava†, which depicts his violent nature as the destructor of the Universe. The Dance performed by Goddess Parvati is known as â€Å"Lasya†, in which the movements are gentle, graceful, erotic and it is also called the feminine version of Tandava. Therefore, according to Kapila Vatsyayan, Bharata attributes to dancing a divine origin, a literary and religious heritage both in thought and technique and aesthetic secular purpose. It has also been mentioned in Natyashastra, how to interpret the different moods of man accompanied by Bhava, Raga and Tal – all directed to create rasa or emotion in the spectators who are called â€Å"Rasikaas†. From the 7th and 8th century, â€Å"Sangeet† occupied a prominent place in the society. The art of sculptures also made great strides and most of the sculptures depicted various dance poses. Temples were the places of origin whereas the dancers or the priests danced in praise of the Lord enacting various mythological stories. Temples sprang up where the devotees gathered to pray to the Almighty God or hear stories about Him. The Temple connection is well established as can be seen in the art of â€Å"Kathavachakas† who carry on the tradition to this day in the North in the Temple boundaries and in open spaces. With the passage of time, in the medieval period, the Bhakti movement influenced all over India. The vast spiritual empire established by Vaishnavism in the North embraces life in its totality. The fine arts found a fuller expression by the 15th and the 16th centuries A. D. Literature, music, dance, painting and other fine arts flourished with the patronage extended by the temples, priests and devotees. In particular the Rasa Lilas in Braj and the neighbouring areas of Mathura in the North sustained the tradition that centered round Vishnu and his recognization as Krishna. The Bhakti movement inspired a whole new school of poetry, dance and music. Krishna and radha are the presiding deities of Vaishnavism and it was on the basis of Leelas of Krishna that precious and distinctive art heritage of Vaishnavism was built up. Mirabai, Surdas and Tulsidas for e. g. wrote powerful devotional verses on longing and separation, expressing the yearning of the human soul for union with God. They chosen the themes was the love of radha for krishna. Krishna Leela though brought out in high relief by Vaishnavism but it had its origin in the past and it can be traced easily to the periods of Mahabharata and Bhasa. In Braj, the Rasa lila’s developed as a combination of music, dance and narration that was used to enact the Krishna Legends – especially the Radha-Krishna idea and stories of Krishna’s youth with the gopis or milkmaids. Hence, the earliest compositions in kathak were based on the religious and stylised music of North India, notably the Dhrupad, Keertan, Hori, Dhamar, Pad and Bhajan. According to Mohan Khokar, Keertans are similar style to dhrupad, but they may, unlike the latter, also be sung in chorus. Keertan is a spiritual practice belonging to the path of Bhakti (devotion). Keertan more specifically means the chanting of sacred sounds or mantras. The Rasa Lila miracle plays of Braj were formerly staged to the accompaniment of keertan music only. Keertans were meant both for singing and dancing. Whereas Bhajans are strictly devotional songs and are in praise of deities such as Krishna, Shiva, Rama, Ganesha, Durga, etc. The songs are rendered in ragas, but improvised tunes are also freely used. Stories and episodes from scriptures, the teachings of saints and description of Gods have all been the subject of Bhajan. Bhajans of Mirabai, Tulsidas, Surdas, Kabir, the Ashtachhap poets and other composers are a part of kathak repertoire. Some of the Famous Bhajans of Mirabai is the following: â€Å"Baso more nanun mein nandlal, Mor mukut makrakrit kundal, arun tilak diyo bhal, Mohni murat – saavari surat, naina bane bisaal, Adhar sudha – ras murli rajat, ur baijanti maal. Chhudra ghantika kati tat sobhit, nupur sabad rasaal, Mira’ prabhu santan sukhdai, bhagat – bachhal gopal† With the advent of the Mughals, the Hindustani music underwent a drastic change. The stylised music absorbed the Mughal influence in a remarkable manner. The dancers moved from the temple courtyard to the palace dubar and this necessitated changes in presentation as Muslim kings could not enjoy the bhava of Bhakti Rasa. Kathak received encouragement at the hands of Nawabs and Rajas. Whereas formerly it was religious and devotional in mood and temperament, now it turned into a means of entertainment. The forms like Thumri, Dadra, Ghazal evolved and became a part of the Hindustani music. The word â€Å"Thumri† has been derived from a combination of two terms i. e. ‘thumak’ (or the chaal) and ‘rijhana’ (or to please). Thus, together meaning graceful stamping of the foot. Thumri is a verse that has Krishna and Radha or Krishna and Gopi’s as its central theme. It is essentially based on the divine romance portraying both aspects of separation and union. The last Nawab of Oudh, Wajid Ali Shah was an accomplished dancer and musician. He composed thumries in classical style and these were sung by the kathak dancers. His contemporaries and the court musicians like Kadarpiya, Akhtar Piya, Lallan Piya, Sikandar Piya and others contributed to its popularity. Although he was a muslim, he liked the Radha-Krishna themes. He himself presented a dance on the Rasa Lila which he called ‘Rahas’. His famous thumries are the following: â€Å"Babul mora nehar chhuto jaye, Chaar kahar mil, doliya uthave, Apna begana chhuto jaye. † Another Thumri: â€Å"Jab chod chale lucknow nagri, Tab hale ‘ali’ par kya guzri, Mahal mahal mein begum rove, Jab hum guzre duniya guzri. † According to PeterLamarche Manuel, Bindadin Maharaj is regarded as one of the most important figures in the development of Thumri as well as Kathak. The kathak Masters Bindadin and his brother Kalka Prasad composed Thumries that were suitable for kathak dancing. Some of the famous Thumri of Bindadin Maharaj is the following: â€Å"Mohe chhedo na, nand ki suno challa, Badi der bhai, ghar jane de mohe.

Is Foreign Aid a Blessing or Curse?

Since the time of independence Pakistan has been facing macroeconomic exertions, such as vicious circle of poverty, less utilization of available natural resources, unfavorable political circumstances that influenced domestic economy and so on. To seize the deficiency, Pakistan has had to depend greatly on financial assistance made by distant countries. Pakistan has been seeking aid since 1947 from global lenders including International Monetary Fund (IMF), Asian Development Bank (ADB) and World Bank.This financial aid poured mostly in the form of loans or debts with high interest rates. Focal of such assistance is the socio-economic development of the country. Financial assistance once taken as a blessing, appeared as to remove all the dearth of the economy. Resultantly many of the sectors started nourishing at par. Pakistan commenced its way towards developing nation but 2005s earthquake ruined Pakistan leaving its awful economy further worsen.Though foreign aid showered in the cou ntry but, in fact, it directly went to the bank accounts of few effluents and hence with the passage of time, it proved that foreign aid has become a curse instead of becoming blessing, not only perished the confidence of local people but corrupted more government officials. All the authorities here are now seeking more and more aid rather than to rely on their own available resources. Pakistan has already borrowed too much foreign aid in the form of loans and is still borrowing that has reached the historic over $60 billion.Debt burden is continuously increasing so its interest rates that worth more than the debt itself. Now the economic position is so deteriorated that for the payment of interest, Pakistan tries to get more loans. Pakistan has become now an aid addict and does not make policies to develop their economy with their own domestic resources. Officials do not pay attention for the development of the technology. They just become entirely dependent on others. Major portio n of aid particularly commodity aid is misappropriated by the concerned Government officials.Moreover, when aid is in terms of commodity such as wheat etc, which many times is provided at a very nominal price, discourages local production of that commodity because of higher cost of production within the country. This situation discourages local agricultural production. If donor country has assisted in establishing imported substitution industry then raw material for the industry will have to be imported from loan given country otherwise industry will not continue its production because particular raw material is not available locally.This causes heavy foreign exchange burden on economy. Pakistan is obtaining foreign aid for bridging gap between domestic savings and investment and also to improve balance of payments position but till now it has not been able to accomplish this task, rather both gaps are continuously increasing. Sometimes aid giving countries interfere in the defense and foreign affairs of Pakistan. That’s why it is said that there are always political strings attached to the bilateral loans. Thus this is to be reveal here that all aid is not for economic rationales but also political.Most of the politicians misallocate the aid for its appropriate concern so to raise their pay, power and prestige. Thus aid is also promoting greed and selfishness among the leaders of the realm. Pakistan was accessed as an independent nation but Pakistan is now fully dependent on the aid drug to eradicate all the absences. As soon as a new government takes office it is out to woe the US for aid, begs from the Saudis for a few crumbs and looks to countries like China for handouts. This must stop.To achieve self-respect and start to improve the lives of the impoverished masses the country needs corrective surgery. The starting point should be adopting a culture of austerity and simplicity. The President, Prime Minister, Army Chief and Chief Justice should be given homes and protocol of ordinary citizens. The vestiges of colonial days, the pomp of office must go. Leaders must present themselves as a role model of modesty rather to complex the masses by their luxurious stuff.One has only to look across the border that how people present themselves in public in simple clothes, sans jewels and accessories, where ministers don’t drive in flashy imported vehicles if a role model is needed. The next step is to generate resources by taxing all. The first step should be agriculture. There is no more favorable time than now. In the past 3 to 4 years produce price including cotton have witnesses a runaway increase and most farmers have had their incomes increase by over 400 percent in three years. Income tax is a failure in Pakistan however consumption tax can be promoted.All students going abroad for study should be required to get an NOC which would require their parents to explain the source of funds. All property purchase, vehicle purch ase and airline ticket purchase should require an NTN number. Put in place consumption taxes. For examples vehicles over 1000 cc should progressively be taxed. Measures such as the above would document the economy and bring more of the black economy into the main stream. With a corrupt bureaucracy, political elite and military this may virtually impossible. So a revolution is needed to unshackle Pakistan.

The british colonial experienc essays

The british colonial experienc essays When Christopher Columbus first landed on the island of Hispaniola, he had no concept of what his voyage had discovered. A New World; with boundless land and new frontiers for exploration. Political issues and the powerful Spain prevented England from any ventures into New World colonization. In 1584, Sir Walter Ralegh founded the first English settlement. Roanoke, Virginia, named for the countrys queen, was a disaster from the start. Poor land choice and much difficulty with the Indians led to a failed community. By 1586, when Sir Francis Drake visited Roanoke, the town was dead. No one reason for the disappearance of Roanoke can be found; some believe that the colonists may have been attacked by Indians, or suffered simply from the weather. Theorists believe that several of the occupants left to join native communities. The failure of Roanoke discouraged many Englishmen. No aristocrats were willing to subject themselves or families to famine and disease. Horror stories flooded England, and people did not want to leave. Richard Hakluyt and several others saw the New World as a chance for English advancement. Hakluyt wrote on the many positives colonization could bring to England. Hakluyt cited God, Gold and Glory to raise English nationalism and encourage New World colonization. The beginning of semi-successful English colonization did not occur until almost twenty years later with the settlement of Jamestown. Jamestown would be followed by distinctly different colonies that were founded by Englishmen as time moved on. Jamestown, Virginia was named for King James who gave the London Company a charter to settle there. In 1806, Sir Thomas Smith sailed for the New World. Only men came to Jamestown in 1806. The settlers picked a plot of land that they decided would be a perfect spot to protect against Spanish invasion. The men promptly built a fort to secure the colony. They didnt build schoolhouses or churches. The ...