Carrying out an open-loop step response on the process trainer pt326

Carrying out an unclouded up- spiral step response on the act trainer pt326INTRODUCTION The accommodate ashess be based up on the behaviour of the dynamics dodges and it is also a branch of the engineering and mathematical model of the process. The want takings of the carcass is called as reference. A affirmler is device which observes and outcome the changes in the end product that are affected by the gossip variables. And it is also use to operate the input variables to a system to achieve the desired result on the output of the system. It is very simple and flexible to solve apply the mathematical model. In comprise system design, we have a concept of feedback manoeuvre system. The main concept of this feedback loop is to control the system performance and it is a negative feedback because the sensed value is subtracted from the desired value to produce the wrongdoing presage which is amplified by the comptroller. To avoid the problem of the open-loop control sy stem, the control system initiated the feedback loop. Where as in close loop system, the control system uses the feedback to control the output of the process. One of the most widely used controllers in the design of continuous data control system is the pelvic inflammatory disease controller, where PID stands for the proportionate plus intrinsical and derivative control. The PID controller is mostly used in the feedback control design. The controller is used for the operation of the error signal to produce the control signal.Proportional (P) controlThis is the one type of action performed and used in the PID controllers is the proportional control. It is the simplest form of continuous control system that sack be used in the closed loop system. Proportional control is used to minimize the fluctuation in the process, but it does not furnish to bring back to the ask tempered point. P-only controller provides the faster response than other controllers. The system first allows t he P-only controller in order to get the system a few seconds/minutes faster. The main advantage of the P-only controller is the faster response metre, it produces the deviation from the set point and this deviation is called offset. numeric EquationsP-only controller linearly correlates the controller output (actuating signal) to the error (difference among measured signal and set point). In the mathematical form, the p-controller is given below Y(t) = Kc e(t) + b Where Y(t)= controller output Kc = controller gain e(t)= error b= bias In the above equation the controller gain and bias are constant to each controller. The controller gain is the change in the controller output per change in the controller input. Bias is simply a controller output, when the error is zero. In the PID controller, when the signals are transmitted then the controller gain relates the changes in the output potentiality to the changes in the input voltage. Thus, the gain ultimately changes in the input and output properties. If the controller output changes more than the input, Kc is greater than one. If the change in the input is greater the controller output, Kc is less than one. Ideally, Kc is bear upon to infinity then the error will be reduced to zero. Exact equalities cannot be achieved in the control logic. In this, the error will be allowed up to certain range of the system. Integral (I) Control This is another(prenominal) type of action performed in the PID controllers is the integral control. Integral control is the second form of feedback control system. It is obtained used to remove the deviations that may exit. Thus the system moves to the calm down state and original settings. A positive error will cause the signal to be increase and whereas a negative error will cause the signal to be decrease the system. However, I-only controller is much slower in response time than the P-controller. Thus, the slower response time will be reduced by combining with another fo rm such as P or PD controller. It is often used to measure the required variables to remain within a narrow range and also require a fine tuning control. Mathematical Equations I-controller correlates the controller output to the integral of error. The integral of error is taken with respect to time within a specified interval. In the mathematical form, the I-controller equation can be represented as Where C(t)= controller output Ti = integral time e(t)= error c(t0)= controller output before integration.Derivative (D) Control This is another type of action performed in the PID controllers is the derivative control. I-control and D-control are a form of a feed forward control. D-control anticipates the process conditions by analyzing the change in error. It main function is to minimize the change in error, thus keeping the system in a incorporateent setting. The main benefits of the D-controller is to resist change in system, the most important of these being is oscillations.PI-co ntrollersPI-controller is a combination of both proportional plus integral controller. This is the feedback controller which drives the process/plant to be controlled with sum of error and also the integral of that value. In PID controllers, we have not yet used the D-controller (D=kd=0). The basic block diagram of the PI controller is shown below,The controller output for the above closed loop system is Where is the error of actual measured value from the desired set point. = SP PV. The main advantage of the PI controller the integral terms in the PI controller causes the steady state error to be zero for a ramp input. The main disadvantes of victimisation with the PI controller is the phase lag. This means that the phase margin decreases.Required Apparatus The report of this experiment is carried out on the Feedback Process Trainer, PT326. The design of the control system consist of a computer ,A/D and D/A converters, and a printer used to provide the copies of the response system. The networked PCs used to obtain the system design using the nyquist simulation method employing the design and simulation program CODAS.Explanation of PT326 According to the industrial situation, the PT326 process trainer model is commonly used. This situation appears when the temperature control is required in the presence of transport delay and transfer lags. In this PT 326 process trainer, the trainer involves air that is strained from the atmosphere through a outward-moving blower and it is heated and passed over the heater through duct before it is being heated. The objective of the control is to sustain the temperature of the air at the required level. The temperature control can be achieved by varying the electrical power supplied to the heater grid. By using the bead thermistor which is set in the flow at any three position along the duct, the air temperature may be sensed. The process trainer introduces the transport delay in the system which is located between the thermistor and heat coil. By setting the opening of the throttle, the mass flow of the air can be correct through the duct. The temperature sensors can be placed at any three of the position in the duct, so that these sensors can acts as a detector. The variation in the resistance of the temperature sensor is converted to the voltage variation through the bridge circuit and is available at terminal Y. The output of the temperature sensor can be used as feedback for connecting the terminal X and Y. The required temperature can be indicated by adjusting the knob label set value. In additionally, the set value can change the step by using the command throwing the switch as internal. An external referrence input can also be provided using the label as external. The difference between referrence input set value and feedback signal is availabel at terminal B and can be supplied to the heater power affix so that the gain can be adjusted by using the prportional band. To select a cont inuous control, the signal at A can be send directly to the heater power supply by using the switch s. The switch s can be alternatively used as on-off controller as well as it is used to select the two step control. This on-off control command reponds to the maximum heater power when on and for the zero heater power it is off. The hysterisis is an on-off controller which can be adjusted by the knob label as overlap. The maximum heater supply can be adjusted using the knob label as max heater power. The process may be seen to comprise a simple blower in which air is drawn from the atmosphere, blown past a heater grid and along a tube having a provision for several temperature to pick up. The purpose of the control system is to maintain the temperature of the air flowing in the tubeat some required set point. The output of the process is a temperature which is measured by the use f the thermistor bead transducer and bridge circuit. agency In the set of experiments of the PT326 proce ss trainer, a personal computer acts as a contoller. Three controller are going to be investigated, a) Proportional control b) Integral control c) Proportional plus integral control. The final experiment make use of the analytical control system to show how the control possible action can be used to calculate the behaviour of the control system. a) Proportional control development the computer program go into the controller setting menu. hardened the controller to be a proportional only type i.e set the kp= 0.1, ki= 0, kd= 0. On the process trainer, adjust the throttle to 25o and place the sensor in the position away from the heater. Vary the proportional gain and plot the represent of the steady state error against the proportional gain. Choose the value of gain we infer for the dress hat response and obtain the screen horseshit to get a copy from the printer. Finally, indicate on graph the onset of instability. b) Integral control Using the computer program go into the cont roller setting menu. Set the controller to be a integral only i.e set the kp= 0, ki=0.1, kd=0. On the process trainer leave the throttle at 25o and kep the sensor in the position away from the heater. Vary the integral gain and plot a graph of steady state error against the integral gain. Choose a value of gain that gives the best response of the system and obtain the screen dump. Finally, indicate on the graph the onset of instability. c) Proportional-plus-Integral control Using the computer program go into the controller setting menu. Set the controller to be proportional-plus-integral type i.e set the kp=0.1, ki=0.1, kd=0. On the process trainer leave the throttle at 25o, and keep the sensor in the position away from the heater. Vary the proportional and integral gains until we get the best response from the system and obtain the screen dump. d) Open-loop step response Using the computer program PRESS o this will put the system infra the open loop control. The programme will the n automatically carry out an open loop step response. Obtain a screen dump for the open loop step response. From the loop step response it is possible to calculate the transfer function of the process trainer. The tranfer function has the form Where K is the open loop D.C gain of the system and Td is the pure time delay present in the system and Tp is the time constsnt for the system. It is possible to measure these values directly from the open loop step response.The steady state error for the control system can be derived as Steady state error = V/(1+kp k) e) after(prenominal) obtaining the open loop step response values like K, Tp, Td, e and R from the graph.Place the values of K,Tp and Td in MATLAB simulink. To simulate the plant only in open loop in CODAS. Compare the time response with the actual plant open-loop response. f) Introduce the controller into the simulation and in frequency domain, adjust proportional gain to give the gain margin of 2 i.e., Nyquist plot (control ler plus plant, open-loop) cuts the real axis at -0.5. observe the fit time response(controller plus plant, closed loop in time domain). g) Following the Nyquist method (f), introduce an integral control term and observe the time response. h) Keeping the proportional plus integral control established in (g), adjust the overall gain(k) to give gain margin of 4,2,1.333,1 and 0.8 (corrresponding to the Nyquist plot cutting the real axis at -0.25, -0.5, -0.75, -1.0 and -1.25 respectively). Comparing the corresponding time responses on the same graph. i) Now,changing the overall gain back to 1 and substituting the proportional and integral gains as calculated using the (i) ziegler-Nichols and (ii) cohen and coon formulas. And comparing the time responses for the three methods (Nyquist,Ziegler-Nicholos and cohen and coon) on the same graph. j) Moving back to the industrial trainer, and substituting the PI gains that where obtained using the Nyquist method and observe the closed loop re sponse. And finding to get fine tune PI gain to improve the performance of the system.MATLAB CODE (CODAS Program) The diagram represents the open loop step response of the system is The legislation for the plotting of the open loop step response of the sytem ishold onxlabel(Time)ylabel(Input (red), Output (green))title(System response to a step input)plot(t,x,r)plot(t,y,g)grid on The code for the plotting of the closed loop step response of the system is hold onaxis(0.0 10.0 -10.0 2900.0)xlabel(Time)ylabel(Desired Output (blue), Actual Outputs)title(System responses to a step input)plot(t,x,k)plot(t,y,b)grid on The code for the nyquist process trainer in the nyquist plot for the closed loop response of the system is % Plant Gp(s)=K*exp(-Td*s)/(1+Tp*s)%K=1.266 % DC GainTd=0.35 % Time DelayTp=0.729 % Time Constant%num_p=Kden_p=Tp 1disp(Plant Transfer Function )plant_tf=tf(num_p, den_p,InputDelay,Td)%% Compensator Gc(s)=Km*(Kp+(Ki/s)+Kd*s) = Km*(Kd*s2+Kp*s+Ki)/s%disp(Km )%Km=1.0Km =2.0/(2)%Km=1.0 % MultiplierKp=2.1397 % Proportional GainKi=0.857 % Integral GainKd=0.0 % Derivative Gain%num_c=Km*Kd Kp Kiden_c=1 0disp(Compensator Transfer Function )comp_tf=tf(num_c,den_c)%OL_tf=comp_tf*plant_tf%%Gain and Phase Margins%Gm,Pm,Wcg,Wcp=margin(OL_tf)disp(Gain Margin ) Gmdisp(Phase Margin ) Pm%% Nyquist plot of OL TF for 0.2

Risk and return strategies

Risk and return strategiesPortfolio commission is principally about lay on the line and return strategies.IntroductionPortfolio management is principally about risk and return strategies. Portfolio management is concerned with the construction and management of investment additions. There atomic number 18 devil principal school of portfolio management hands-off and active. A unresisting and active term refers to the method by which the assets are selected for inclusion into the portfolio. A passive portfolio includes the commercialize portfolio consist of shares in all companies quoted on the stock exchange, or a selection of group of stock e.g. all technology stocks. Passive portfolio therefore does non make any attempt to research each stock and decide if it should be included or excluded from the portfolio. There is no technical or unfathomed analysis carried out in order to beat the grocery portfolio. Passive equity portfolio management is all about long-term buy and hold strategy, ordinarily tracking an index over time. This is designed to match the market portfolio performance. dynamical portfolio management on the other hand uses research, analysis (both fundamental and technical), economic factors and likewise an element of subjective judgement in selecting stock into the portfolio. It is believed that the stocks are undervalued and will out perform the market portfolio in the future.PlanningThe planning stage of portfolio management involves a written investment policy statement. A clearly defined investment policy that includes the preferred management technique, hence, active or passive indexed portfolio management. It as well outlines the portfolio goals level of returns and defined risk tolerances for the portfolio. The planning alike involves rebalancing strategies and means of effective internal and external communication of those goals.Asset AnalysisAside from inside cognition asset selection advice is based on two principal typ es of investment analysis technical analysis and fundamental analysis. Technical analysis is based on studying past trends in share prices in the belief that patterns can be discerned in their movements which can be used to predict future movements. This uses graphs of diachronic share price variations and it is often referred to as chartists analysis.Fundamental analysis concentrates on the study of the rudimentary position of the company. Such details as its strengths and weaknesses and future opportunities and threats, also uses ratio analysis in evaluating a particular stock.Asset Selection and CombinationStock selection as part of Active portfolio management has rattling limited impact on the return investors earn, as a result of stock markets being economical. The efficient markets hypothesis (EMH) holds that a stock market is efficient if the market price of a companys share quickly and correctly reflects all relevant information as it becomes avail fitting (Lumby, S., Jo nes, C., (2004)). In asset selection and combination we need to remember that investors are risk-adverse and select their portfolios by the mean/variance criteria (i.e. they are markowitz efficient investors). However, asset combination does result in an increase portfolio returns as a result of how the investment are combined and allocated within the available asset classes. The combination of stocks vs. bonds vs. cash, large companies very smaller ones, UK companies vs. foreign stocks and value companies vs. growth companies.Evaluation of PerformancePortfolio performance evaluation involves return measurement (weight average return) over several periods. Performance measures such as market timing and security analysis. Style analysis is used to describe a portfolio by evaluating how its returns act, rather than by using a simplistic concept of what the portfolio included. Its accusive is also to provide a superior mean of performance measurement for stocks and also the skills of the fund manager. Style analysis uses an asset class factor putRi = bi1Fi1+bi2Fi2+ + binFin+eiWhere Fi1 Fin are return factors and bi1 bni are sensitivities to the factors.All factors are return factors to the portfolio. The factors used in the portfolio are stock index, bonds, value stock, growth stock and so on There are many ways to evaluate the performance of a portfolio, style analysis is one of the newest techniques and it al measlys us to explain how portfolio returns behave. It is also a helpful mean of stock selection for the portfolio.Re BalancingRebalancing the portfolio is critical for the financial future. Rebalancing involves buying low and selling high. This process ensures that the portfolio is in line with the sign portfolio asset allocation plan. As the economic conditions change some assets within the portfolio will appreciate faster then others and their weighting within the portfolio will change from the initial allocation plan. This will result in an ou t of balance portfolio and will need rebalancing by selling high performing stock and buying low performing ones.Indexing Advantages and DisadvantagesAs the stock markets are efficient there are various advantages in index bills over actively managed funds as a portfolio management method. EMH theory states that security markets are extremely efficient in processing individual stock information so undervalued shares are difficult to consistently identify and purchase. Another advantage is the lower expenses in managing an index fund over an active fund. Also lower trading be versus actively managed funds where stocks are typically traded more frequently and finally, lower capital gains taxes resulting from shares being sold less often. Disadvantages of indexing are in harm of tracking error suffered as a result of changing economic climax where certain stock will out perform expectations. This could result in the portfolio becoming out of balance and rebalancing results in acco mplishment costs and subsequent errors in tracking the underlying index.Active Portfolio ManagementAn Active investor is one that is not passive. Active portfolio managers portfolio will differ from that of a passive manager. This is due to that fact that active managers will act on perception of mispricing in stock market, and as such perceptions change frequently, such managers tend to trade frequently, hence, the term active.Efficient Market Hypothesis would disagree that such mispricing last in the market and that the stock market is efficient. Therefore, active portfolio managers returns are lower then that of passive managers, due to the increase cost of actively managing the portfolio. If the markets are semi-strong or strong form efficient then active portfolio management in terms of fundamental or technical analysis are waste of time as they will not provide a potential gains in discovering the undervalued stocks. Only if the market were weak form efficient than it would provide fundamental analysis to uncover potential gains. Therefore, active portfolio management is an unrewarding exercise and can lead to waste of both effort and money.Passive vs. ActiveThere are various advantages of passive portfolio management over that of active. We have already discussed the EMH and how that would suggest that active management has very little value in terms of portfolio selection in a semi-strong form of market efficiency. So passive portfolio management costs much less than active management. This give passive investors an increase net returns as the management costs are lower. Passive portfolios are also more tax efficient with their buy and hold unceasingly approach result in low income tax costs. Active portfolio often attracts capital gains tax from sell of short-term appreciated gains in stocks. Passive reciprocal funds have a inherently low turnover of securities and thus are exposed to fewer realised capital gains.Passive portfolios have certain s tyles. A passive investor knows exactly what types of securities he or she is invested in. Active managers, on the other hand, can vary the composition of their portfolios significantly over time a problem known as style drift.ConclusionActively managed portfolio will try to deliver excess returns over the passive portfolio by actively forebode future returns on individual stocks. However, in reality they do not obtain significant excess return of the market portfolio, which is the primary indexing for the passive portfolio management. This is in accordance with the efficient market hypothesis that states that stock markets are semi-strong or strong form efficient, with stocks being priced correctly.Index funds are problematical more successful portfolio management method on the believe that markets are significantly efficient and active manager will not be able to gain excess returns, after taking into account the excessive costs involved in active management. Passive management seeks to deliver the return and risks associated with the chosen index.Evaluation of index funds performance is in terms of how closing the portfolio tracks the underlying index in terms of returns. The costs associated with index funds are in rebalancing the portfolio. It assumes that when the economic condition changes and the assets weight within the portfolio can be redefined automatically. However, in rebalancing the portfolio involves physical selling of high stocks and selling low stocks, which involve transaction costs. This result in tracking errors driven by transaction costs, funds cash flows un-invested, treatment of dividend by the index and index composition changes. Finally, the liquidity of the underlying index stocks can have an impact on transaction costs and subsequently the tracking error encountered by the portfolio.References Bibliographyhttp//www.cypram.com/passive.htmlLumby, S., Jones, C., (2004), Corporate Finance theory and form 7th edition, ThomsonACC A Paper 3.7 (2001) Strategic Financial Management, The Financial Training Companyhttp//www.nseindia.com/content/press/jul2003b.pdfsearch=tracking%20error%20and%20methods%20of%20indexing

History Of The Fertile Crescent History Essay

History Of The strong crescent(prenominal) History EssayThe full-bodied crescent(prenominal) has been cal guide the Cradle of politeness for many course of studys. The Cradle of Civilization is the key to understanding when the world population began to thirve and create vilages, cities, and ultimantly states. With out the domestication and finale of the land there would fix neer been bounteous food to support such a dence population of batch. Hunting and collecting replete(p)ly from the frantic could non possibly support even a tiny fraction of the worlds current population (Bellwood, 1). There were seven core domesticates in the Fertile Crescent, they include sheep, laughingstocks, pigs, cattle, two-grain spelt wheat, einkorn wheat and barley. All of these species were domestic and had an fundamental role in the Fertile Crescent throughout the twain millennia emergence of agrarian societies between 10000 and 8000 B.P. We can best understand the events of this peri od by premier(prenominal) focusing on the developmental history of the individual species of coifs and animals that were brought under domestication, and then combining those individual histories into the to a greater extent complex overall story in the emergence of the agriculture in the region (Smith, 51).The story of the Fertile Crescent starts much before the emergence of the hunter- gatherers were raviging the forests and grass lands. By 10000 B.P. the beginning of the 2000 year period that would witness the development of agriculture, human societies had taken advantage of the post-Pleistocene proliferation of plant and animal resources, and the fertile crescent was inhabited by a divers(prenominal) align of hunter-gatherer societies (Smith, 51). The Pleistocene era had ended with a much warmer climate that also brought a much moister climate to the area. This climate exchange was one that advance the feral annual cereal grasses (Sagan, 249). Also it allowed the sparse movement of hunter-gatherer groups to move in to the area. It was there that they discovered that a much(prenominal) sedentary lifestyle produced more of a greater surplus of food and than that of foraging.The Fertile Crescents environmental zones are keys to understanding the development of the domestications of the plants and animals. There are three main environmental zones obscure in the origin of cultivation in the Fertile Crescent. The eastern section of which comprises the foothills and margins of the Zagros Mountains (Maisels 133). The central or the north is mostly make up of the broad wheeling grasslands. Lastly, the western section whose central axis is the primal Levantine corridor and Jordan Valley (Smith, 51). While deliberate cultivation eventually became most intensely practiced on the alluvial plain of Mesopotamia, it did not start there because the climate was too dry, thus requiring irrigation. In the central section, habitual fruiting of undue instills di d occur, and it is suggested that this abundance led to the first sedentary villages dependent on harvesting wild grains. Ali Kosh a village occupied around 9000 B.P. herded goats, intensively collected various wild plants, and harvested wild wheat. Deliberate cultivation most likely came in response to documented climatic changes, which led inhabitants on the fringe of the hilly flanks to artificially duplicate the profound stands of wheat and barley that grew in the hilly flanks (Sagan, 237).There were many changes that occurred due to the cultivation of a plant or animal. These changes were many times become inherited due to the consistent selection of the more adequately produced products. In wild grains, the axis or rachis is brittle, which allows the grain to reseed itself easily. Selection of the grains was at first an accidental by-product of harvesting, and later intentionally, the state selected grains in which the axis was tougher, allowing less(prenominal) grain to fa ll to the ground, thus raising yields (Sagan 247). They also selected plants that were more easily husked. The nation used the same natural selection process when choosing livestock. They selected woolly animals from among wild sheep, who are not normally woolly, thus acquiring sheep better suited to lowland heat and from which to obtain wool. Fossil remains indicate that domestication of sheep and goats was accompanied by a decrease in the size of the animal.The animals domestic in the Fertile Crescent were key to the development of the humans in the area. The readily available source of meat aided in the functions of the brain, which led to the ability to think more complexly and creatively. The brain is fueled by protein therefore with more protein in the diet the mind began to develop more completely. Thus the importance of the domestication of the animals to the human race, with out having to hunt for the meat they were getting a more readily available source of protein (Wilk inson 139).The Persian wild goat has been recognized as the ascendant to the first domesticated goat. The Persian wild goat tends to be found in the more rugged terrain. It is in the eastern section of the Fertile Crescent that we find the most enjoin of goats being hunted for their meat. Specifically at the site of Ganj Dareh, which was excavated in 1970s, which found at the lowest level, which dates back to 9000 B.P. contained approximately 5000 identifiable goat bone up (Old Goats). Brian Hesse of the University of Alabama at Birmingham studied these bones. Using new analytical techniques to try to piece together evidence of the domestication of goats. Hesse theorized that a domesticated herd should have two clear distinguishing characteristics (1) a boastfully percentage of animals slaughtered for meat late in their immaturity, when they had attained much of their with child(p) size (2) an adult breeding population in which females far outnumbered males(Smith, 60). Through complex measurements of the bones discovered at Ganj Dareh, Hesse discovered that the males were being killed before they reached adult hood and the females overwhelmingly stood for most of the population. This stunning breakthrough specifies that an age and sex profile that closely agrees with that of a herd of domesticated goats managed to provide meat (Old Goats). Clear demographic evidence appears to indicate that goats were domesticated at Ganj Dareh as early as 9000 years agone. The increase of the proportions of goat bones among the animal remains is an indicator to the shift to goat herding.Wild Sheep were the second animal to be domesticated in the Fertile Crescent. The wild ancestor of domesticated sheep ranged throughout much of the Fertile Crescent. A salient amount of evidence of wild sheep can be found in the central region (Sagon, 245). There is much info to indicate that the wild sheep was not an important prey in the areas of Levant. There is, however, evidence sh owing that the sheep were a prey in Jericho that date wild sheep back to 10000 to 9500 years ago (Wilkinson 149). The degree to which the hunter-gatherer societies in different parts of the Fertile Crescent relied on wild sheep for food parallels the animals abundance in their local environments 10000 to 8000 years ago. The wild sheep were most were most abundantly discovered in the central region. This is plausibly why around 8500 B.P. sheep were first domesticated in the central area of the Fertile Crescent. There, the land is better suited to the wild sheep thus they were a more common target for hunters in that area, leading to the domestication of the sheep. With the change from being wild to being domesticated, the sheep, according to the fossil record, got clarifieder due to the selection process of the humans tending to the animals. It is in the apex of the Fertile Crescent that sheep herding first became an important component of agricultural economies (Smith, 57).The pig was, as far as we know the third animal to be domesticated. Wild pigs were greatly hunted in the Yankee part of the central region. Facts have lead archeologist to date the bones of the wild pigs to 9000 B.P. The pigs continued to be a substantial part of the diet of the people in this northern area of the Fertile Crescent, even after the shift to the herding of sheep and goats (Sagan, 243). The site of Cayn tends to be the marker for the earliest domesticated pig, in the vicinity of 8500 years ago. There have been some tentative theories that approximate the domestication of pigs to be closer to the date of 10000 B.P. (Smith, 67). It is Richard Redding who proposed this theory, that the bones of the pigs at Hallan Cemi, strongly represent the ages of bones of a possible herding community of pigs. However since we know nothing about the ages of the pigs that the hunters targeted we have no basis for making the claim that the pigs at Hallan Cemi were indeed domesticated and herded . For now it remains unverified but the alluring prospect that pigs were domesticated much before the evidence now shows.Cattle were probably the last and least important of the four main animals that were domesticated in the Fertile Crescent. The ancestors of domesticate cattle were probably considered to be a dangerous leave due to the size of the animal. However, it was also a significantly large package of meat. The area in the Levant and Jordan Valley has dated wild cattle bones to approximately 9000 to 8000 years ago. Like the pigs the cattle had a exceptionally large geographical range and extended far beyond the Fertile Crescent. There have been clear documentation of a pattern that shows the reduction of size in the cattle between 8000 and 7000 B.P. While cattle may show to be of particular importance to the region between 10000 and 8000 B.P. it later became the dominant species of the market (Smith, 56).Now that we have looked at the individual histories of the animals o f the seven core domesticates of the Fertile Crescent we see many patterns are emerging. The four species share common lines of evidence that include geographical range, increase in abundance, reduction in size and change in age/sex profiles (Smith, 67). This evidence has lead to the indication that these histories were distinct and still follows the same indication of domestication. The goats were domesticated in the earliest portion of the period, at around 9000 B.P. Then the sheep, pigs and cattle soon followed after approximately 300 years after the domestication of the goats.Now that we have explored the four animals that were domesticated in the Fertile Crescent we must now turn to vegetation that grew and was domesticated in the Cradle of Civilization around the same time the animals were being domesticated. With the more sedentary lifestyle that the people of this time were adapting to they must have turned to the land and noticed that the annual growing cycle of the plants could help them support them selves without having to harvest the wild plants. They realized that the plants could be grown to fit their needs. There were about eight species of plants that were domesticated during this time (Smith, 48). However, only three of those eight show enough evidence to be mentioned, those three are emmer wheat, einkorn wheat and barley. These three plants were developed in to crops that become overwhelmingly important to the societies that thrived during this time.The first domesticated plant was emmer wheat. Wild emmer wheat was confined in the Fertile Crescent and grew in the areas of Levant, where it was domesticated. As emmer was domesticated, the shape and size of the grain changed, as did the structure of the rachis, the miniature stem that attaches the grain to the plant (Smith, 68). The grains became heftier and the stems became and sturdier. With the grains being more fruitful and staying on the plant longer it aloud more of the grains to be harve sted and less of them lost. The morphological changes indicate that the emmer was domesticated. One of the first sites to show the domesticated emmer was the site of Jericho. The grains were found to be from approximately 9800 to 9500 B.P. or perhaps earlier. The large grains of wheat with the nonbrittle rachises, the stem that connects the grain to the plant, appeared around the same time in the lower levels at the site of Aswad, near Damascus (Smith, 68). It didnt take long for the domesticated Wheat to spread throughout the entire Fertile Crescent. By approximately 8000 B.P. the entire area was producing signs of domesticated emmer wheat.Wild einkorn wheat was the next to be plant to be domesticated. The einkorn wheat was actually harvested by the hunter-gatherers before it was domesticated and intentionally grown. The grain is practically absent from the sites in the Levant, however it occurred in grossly high amounts in the areas of the Mesopotamia and the Anatolia, however the most important sites for the domestication of this wheat were in the central part of the Crescent, at sites such as Mureybit and Abu Hureyra. It is Abu Hureyra that holds the most data for the domestication of einkorn (Smith, 68). When it was excavated in the early 1970s, Gordon Hillman and his colleagues at the Institute of Archaeology of University College, conducted a large scale flotation recovery program that provided them with an exceptionally large and diverse assemblage of charred plant remains. Painstakingly analyzing the all 712 samples recovered, each of which contained about 500 seeds representing 70 species of or genera, Hillman and his co-workers were able to reconstruct the plant food diet of some(prenominal) the body politic community that existed at Abu Hureyra from about 9500 to 8000 B.P. and the earlier Hunter-gatherer group that lived there in a permanent year-round settlement from 11000 to 10000 years ago. Of the 157 seed-bearing species harvested by the hunt er-gatherer wild einkorn was among those most frequently, its seeds showed up in almost all of the flotation samples from these early levels (Smith 69). At the nearby site of Mureybit even convincing evidence was produced elucidative the strong reliance on the grain in the hunter-gatherer tribes even before the einkorn wheat was brought under cultivation.Barley is the only plant that is present throughout the entire Fertile Crescent and through the same time period as the both the emmer wheat and the einkorn wheat. While the record of early-domesticated barley overlaps with the other two forms of wheat, it exhibits several interesting differences. There were two forms of the barley that were domesticated and have been recovered from the early farming settlements. One of the plant species had two verical rows of grains, with each grain protected by an outer hull (Smith, 71), the other species contained six rows of grains to each stalk of the plant. The two-rowed barley was domesticat ed about the same time as the emmer wheat, about 9800 to 9600 B.P. However the six-rowed barley produced more harvest then the two-rowed barley, therefore, it was quickly domesticated soon after that of the two-rowed stalks. By 9500 to 9000 B.P., the six-rowed barley is the only species that was domesticated on with the emmer and einkorn wheat (Sagan, 245).The absence of a clear pattern of crop combination is perhaps the most interesting observation that can be made regarding the early domestication of the three plants. However, the advances in storage technology, allowed the former hunter-gatherers to exploit the cereals by grinding their seeds into a mill. This mill was easily kept and this allowed for food mathematical product in the colder months when the plants did not grow (Wilkinson, 151).The use of trade had a considerable effect in the movement of the methods that of growing and cultivating the wheat and other resourceful goods. These resources gained in value through int erregional trade, which in turn resulted in intensified exploitation of the resources. Another result was the movement of the grains outside their indigenous zone, where they were subjected to different selective pressures, resulting in different strains of wheat and barley (Sagon, 243).After the domestication and cultivation of the plants and animals the small villages began becoming states, they were becoming more and more like a modern mean solar day civilization. The early stages of food production in the Middle East were marked by gradual transition from foraging to producing economies. Many changes were caused by the production and cultivation of food. Such changes include population increase, which caused the resulting migration and forced other areas to respond and begin their own cultivation of their resources. Also, there had been a gradual population increase, this was based on the native richness of the environment, which helped spur the spread of food production (Maise ls, 140). On the other hand, in the Tigris-Euphrates alluvial plain, cultivation required irrigation, which began around 7000 B.P. and changed the world of farming. Irrigation allowed farming to spread away from the normal areas that were close to the riverbanks, by bringing the water away from the riverbanks the cultivation began to strive. By 6000 B.P., irrigation systems had become far larger and more complex, and were associated with a new political system. This new establishment was based on central government, extreme contrasts of wealth, and social patternes, the beginnings of the state (Wilkinson, 141). The written and archaeological record indicates that the early Mesopotamian states were metropolis states (Sumer and Elam), ruled by a literate theocracy that managed virtually all major aspects of the economy, which was overwhelmingly agrarian. The theocracy was replaced by 4,500 B.P., it was replaced by a secular, military monarchy, based upon an elaborate class system (Sa gon, 300). Thus ended the revolution of modern humans in the world of cultivation we now knew how to farm and use the animals to our advantage. As time continues to transmutation by we find more and more ways to maximize the products we get from the cultivation of plants and domestication of animals (Sagan, 248).To sum everything up Southwest Asia was inhabited by small groups of hunter-gatherers. These groups, due to the climatic change, became more and more sedentary and begin to develop a source of food production. This production of food came from the domestication and cultivation of plants and animals. The herded animals provided a constant source of protein in their diet and allowed for the hunters to expend their energy in other areas of life. The cultivation of the plants allows for a reliable supply of grains in their diet. This made the people of this time able to support larger families, which turned into villages, cities, and ultimately states.

The Shame of Cigarette Smoking in the Healthcare System :: Journalism Journalistic Essays Smoke

Smokers in scrubs The shame of cigarette smoking in the healthcare system On a recent thorium morning, while some hospital employees deald cigarettes in Brigham and Womens safe haven known as the butt-hut, others crowded the lobby on Frances Street in Boston to check out the American Cancer Societys The Great American Smoke-Out event. Two women sat behind a folding table handing out informational pamphlets on smoking hazards and ways to kick the fatal habit. Several of the women and men who approached the table for information or signed up to get their lung capacity tested were eating away scrubs, a sign that cigarette smoking is still prevalent among health care employees.Hospitals, including Dana Farber, are starting to now reimburse employees who enroll in a quit-smoking program. In some cases, they get back almost $ 500 for counseling, patches, and nicotine gum, said Jennifer Kelly, who runs the smoking cessation program at Brigham and Womens.The smoking cessation program is of fered to some(prenominal) employees and the public, and provides individual and group counseling, which meets one day a week for eight weeks. Kelly explained that each hour- long session costs $10, however the fee is waived for those with free healthcare benefits or Medicare and all participants of the program receive discounts on nicotine patches and chewing gum. With several Boston area programs designed to rid the habit of the 20% of Massachusetts residence, who smoke and with hospitals practically paying their employees to quit smoking than why are 47 million adults in the U.S. still smoking cigarettes?Nicotine is one of the most addictive substances instantly studies have shown that nicotine is as addictive to mint as heroin, cocaine and alcohol. According to a study conducted by the American Cancer Society, in the U.S today, nicotine is the most super acid form of drug addiction among adults, high school students and middle-school students. While studies preformed by the C enter for Disease Control and Prevention have shown that cigarette smoking has declined 40% among adults ages 18 and over, between the years of 1965 and 1999 still today, nearly 26% of men and 22% of women smoke cigarettes.Dr. Laura Fredenburgh, a soft spoken and attractive woman in a white coat with her name and title embroidered on the pocket, sat at a long table on Thursday morning. She carefully explained to people the results of their free lung capacity tests that were given during the Smoke-Out.

Feminism in Braided Lives :: Feminism Feminist Women Criticism

Feminism in tissue Lives Marge Piercy is well known for her feminist views and attitudes throughout her novels. Braided Lives is no exception. The novel follows Piercys pattern of feminist writing. The characters in the novel are victims of societys crimes towards women. The protagonist, Jill, deals with many issues including mess up and abortion. Due to her own experiences with these issues, it becomes her passion to help others in the very(prenominal) situation. Jill constantly strives to be in control of her own life this struggle is another facet of the feminist movement. The goal of the novel is to "make its readers pay to a greater extent attention to the current attack on legal abortion, and make them more eager to react the imperiled gains of the womens movement" (Pollitt 378). Jill and her female companions encounter many difficult situations involving rape. At age 14, Jill is attacked by her boyfriend Freddie. This occurs at a time when Jill is first disco vering her own sexuality and who she is. This experience has an effect on Jill into adulthood. In the novel, she speaks of this experience quaternary years later, when she is preparing to leave for college. Jill recalls this event in vivid detail. I see his face hard and angry and I remember the terror that gripped me on the kitchen theme when I realized he wasnt going to listen to my firm loud nos that time. Terror twitched me violently... (30). Jills cousin and roommate, Donna, is violently raped by a townie. Donna comes to Jill after the rape has taken place. She has been beaten both physically and emotionally. Piercy describes the rape and the aftermath of the rape in great detail. dedicating several pages to describing the horrific acts. Jill wont leave Donnas side and nurses her back to health. Jill takes it upon herself to defend and protect Donna against the man who raped her. This is just one of many times in which Jill defends and protects her female friends against s ociety throughout Braided Lives. Fighting for a womans salutary for an abortion becomes Jills passion in life. This is a result of her own experiences and those of her friends. When Jill is a freshman in college she becomes pregnant by her boyfriend. Neither is ready for the responsibility of conjugation or a child.

Pride And Prejudice :: essays research papers

Pride and Prejudice Is it possible?The novel Pride and Prejudice, written by Jane Austen during the nineteenth century, describes the trials and tribulations of basketball team sisters of marrying age. The story is based in England around the turn of the century, and upon c atomic number 18ful review, we settle that many of the events do not reflect the time period. The relationship between Elizabeth and Darcy, and the Lydia-Wickham affair, are not realistic. Despite the fact that the novel is fiction, it is questionable that such events could take place.When Darcy first lays eyes on Elizabeth after she is pointed out to him by Bingley, his statement is not that of love, nor of fondness, rather it is one of complete disgust.She is tolerable but not handsome enough to tempt me and I am in no humour at present to give consequence to young ladies slighted by other men. From Darcys reaction, we can only imagine what he really thinks of Elizabeth, but we are presumptuousness a very go od idea. This is not love at first sight, there is no attraction between the two, there is nothing at all. Elizabeth has an fair to middling reaction to Darcy. When she overhears the comments he has make about her, she is anything but drawn to the man. Mr. Darcy walked off and Elizabeth remained with no very cordial feelings towards him.(pg.12) The two seem destined to become finish up enemies, in fact they seem to become anything but a couple in love, which is exactly what they end up to be.Soon after their original get together at the ball, Elizabeth and Darcys paths cross again. This time it is at the home of the Bingleys where Darcy is staying, and where Elizabeth comes to visit Jane, her ill sister. When Darcy see her this time, his reaction to her is quite differenthe was forced to bed her figure to be light and pleasing and in spite of his asserting that her manners were not those of the fashionable world, he was caught by their easy playfulness.(pg.22)I find it hard to b elieve that his impression of Elizabeth could change so drastically within a matter of days. Elizabeth, on the other hand, has a more reasonable reaction. She made no notice of Darcys reaction.perfectly unaware to her he was only the man who had made himself agreeable nowhere, and who had not thought her handsome enough to dancing with.

the good and bad of telecommuting :: essays research papers

The good and bad of telecommutingtelecommuting may be the movement of the future, which will allow more tribe to work away from the office. Many people see telecommuting as a way to be close to home or allow them to be connected to their organization while working abroad. While telecommuting might work for some people, telecommuting is not for everyone. There be many disadvantages as well advantages to telecommuting which most people do not take into account. When considering telecommuting, the advantages fall for two employer and employee. The same can be said about the disadvantages of telecommuting. Advantages of teleworking One of the main driving factors for any company is economics and how will telecommuting allow the corporation to be profitable. The primary saving for companies embarking upon the telecommuting innovation is the reduction in the amount of office space mandatory to conduct business. Telecommuting benefits the employer because they have an expanded pool of employees. The skills of employees with commuting difficulties, childcare conflict, disabilities, geographical barriers are made available to a telecommuting employer. Companies are now starting to expanding oversees where the labor price is cheaper for telecommuting. This however can be looked at as both an advantage to the employer, and as a disadvantage to the employee. The advantage of telecommuting for some employees can be invaluable. One huge advantage an employee has when telecommuting is flexibility. Telecommuting allows for change magnitude flexibility to coordinate work schedules with individualized and family priorities. Flexible working arrangements improve quality and work done (Dudman, 2001). Achieving a balance between work and personal duties can help individuals gain more control over their lives. Often overlooked is the impact telecommuting has on the surroundings. One great advantage for the environment is the conservation of energy. With a great deal of ener gy is required to produce a vast amount of transportation vehicles such as automobiles, buses and subways. The fuel required to operate these vehicles would be reduced. An employee also is also a great consumer of energy, once at an office, the office building has heating, cooling, and lighting needs. When magnified, the energy use can be great. Whereas working from home requires only a minimal amount of energy use for heating, cooling, and lighting needs. For every advantage, most of the time there are disadvantages associated with it. Disadvantages of TelecommutingOne huge disadvantage that employers face with the use of telecommuting is losing direct control over the employees.