Xdsl Essays - Digital Subscriber Line, DSL Modem,

Xdsl Digital Subscriber Lines Fast and affordable Internet access has become a big issue for private users and small businesses. Today users have many different options concerning Internet access. One can use a 56k/28k modem, cable modem, wireless, Ethernet, an ISDN connection, a T1 or T3 connection, or a DSL connection. Each method of connection has advantages and disadvantages concerning security, cost, and speed. A newer technology for users is DSL or a Digital Subscriber Line. DSL uses existing phone lines to send info. Unlike a dial up analog modem, a DSL connection allows voice and data to be sent at the same time on the same phone line, the bit rate is faster and the connection is continuous (no need to dial up). DSL Technology DSL is a technology for pushing high bit rates through last mile telephone connections (small gage copper less that 18,000 ft.). For most people, point A will be their home and point B will be the substation of the local phone company. DSL modems, unlike conventional modems, establish a connection from one end of a copper wire to the other end of that copper wire: the signal does not pass into the telephone switching system. DSL modems are not limited to using only the voice frequencies passed by the standard telephone system (usually 0-4kHz), DSL modems typically use more than 100kHhz. (Day 1999) When the local loop carrying the voice/data reaches the local phone company the loop first goes to a splitter which separates the voice from the data. The voice frequencies are sent to the traditional telephone switching network used for voice transfer. The data frequencies are wired into a DSL modem at the central office (CO) end. The resulting high-speed digital data stream coming from (or going to) the consumer is handled as digital data (not analog voice) and may be hooked into a number of networks connection to the data's destination. The data never enters the standard telephone switching system. (Day 1999) When you connect to the ISP (Internet Service Provider) you are not connecting to the ISP over its standard modem bank, instead you are coming in over some sort of LAN/WAN (Local/Wide Area Network) data connection that the ISP has arranged with your local phone company. This is the only way an ISP can provide DSL-connected ISP service for customers. Because of the connection to the area network the DSL connection is always on, there is no need to dial up and connect to a modem. (Day 1999) This is a good graphic network map from dslreports.com DSL Protocols There are many different protocols and sub protocols that fall under DSL. Some of the main protocols for DSL are: -ADSL-Asymmetric Digital Subscriber Line (1.5 Mbps-9Mbps) (DNAI 1999) -RADSL-Rate Adaptive Digital Subscriber Line (test and adapts for fastest speed) (DNAI 1999) -HDSL-High bit-rate Digital Subscriber Line (T1 Speeds, currently requires 2 lines) (DNAI 1999) -VDSL-Very-high-bit-rate Digital Subscriber Line (ten times as fast as ADSL, not on market yet) (Clarke 1999) DSL networks have modems at both ends of the connection, the customer's modem and the ISP's modem. Because different protocols use different hardware (modem) the ISP chooses what protocol will be used. Hardware Although it depends on your ISP and the equipment they use, typically you will need a 10Base-T adapter with which to connect to the external DSL modem, and a personal computer. Keep in mind that with different protocols you will need different DSL modems. If you are putting together a LAN you will also need a hub or preferably a switch. Usually the customer DSL device is implemented as a bridge, router or both. (Kristoff 1999) Splitters and Filters Because the same line is used to send voice and data frequencies it is possible for interference to occur. Sometimes a phone will go above the 4kHZ frequency and cause interference with the DSL data stream. Another problem is the high frequencies used by the DSL modem can be picked up by the phone resulting in static on the headset. The original solution to 4kHZ interference problems was to use a POTS splitter. A splitter takes the phone line and forks it. One line goes to the telephones and the other goes to the DSL modem. Besides splitting the line the splitter acts as a

Global Food Production essays

Global Food Production essays The present world population exceeds 6 billion people. Incredibly, of those 6 billion about half suffer from malnourishment. In the past, people viewed malnutrition as a problem of hunger and famine amongst poor countries. However, the definition of malnourishment has broadened to include a deficiency in a persons intake of nutrients and other dietary elements to live a healthy life, as well as an excess in the intake of nutrients. For the first time in history the number of people that are over-consuming food rivals the number of people that arent eating enough. Over-consumption is a problem of industrialized countries with the United States leading the way. Also, there are profound misconceptions about malnutrition. For example, there is often enough food to go around in countries like Africa where hunger is severe. Also, in U.S., the wealthiest nation in all of history, hunger still persists. The biggest misconception of all is that global hunger is a result of scarcity of food. For more than 40 years the world has produced regular and often bountiful food surpluses. So why then does malnutrition affect half of the worlds population? Delving into this problem we find that malnutrition is only the tip of the iceberg to a much more intricate global problem. As we analyze the problems of worldwide malnutrition we find it is interconnected to global food production systems, land and water degradation, poverty, and the political-economy of globalization. We find that malnutrition is only the face to a whole body of problems. It is the first visible symptom of our present day food production system. It directly affects populations which we easily identify with. Looking beyond the immediate effects of malnutrition, we find connections to the degradation of the environment on a global scale. Malnutrition leads to another problem, and another to another, and so on and so forth. As our perspective widen...

A Timeline of the History of Alcohol

A Timeline of the History of Alcohol The history of alcohol and humans is at least 30,000 and arguably 100,000 years long. Alcohol, a flammable liquid produced by the natural fermentation of sugars, is currently the most widely used human psychoactive agent around the world today, ahead of nicotine, caffeine, and betel nut. It was made and consumed by prehistoric societies in six of the seven continents (not Antarctica), in a variety of forms based on a variety of natural sugars found in grains and fruits.   Alcohol Timeline: Consumption The earliest possible moment that humans consumed alcohol is conjecture. The creation of alcohol is a natural process, and scholars have noted that primates, insects, and birds partake in (accidentally) fermented berries and fruit. While there is no direct evidence that our ancient ancestors also drank fermented liquids, it is a possibility we should consider. 100,000 years ago (theoretically): At some point, Paleolithic humans or their ancestors recognized that leaving fruit in the bottom of a container for an extended period of time leads naturally to alcohol-infused juices. 30,000 BCE: Some scholars interpret the abstract parts of Upper Paleolithic cave art as the work of shamans, religious specialists who were attempting to connect with natural forces and supernatural beings. Shamans work under altered states of consciousness (ASC), which can be created by chanting or fasting or aided by pyschotropic drugs, like alcohol. Some of the earliest cave paintings suggest activities of shamans; some scholars have suggested they reached ASC using alcohol. Laussel Venus, Upper Paleolithic Bas-Relief, Aquitaine Museum, Bordeaux, France. Apic / Hulton Archive / Getty Images 25,000 BCE: The Venus of Laussel, found in a French Upper Paleolithic cave, is a carved representation of a woman holding what looks like a cornucopia or a bison horn core. Some scholars have interpreted it as a drinking horn. 13,000 BCE: To intentionally make fermented beverages, one needs a container where they may be stored during the process, and the first pottery was invented in China at least 15,000 years ago. 10,000 BCE: Grape pips attest to possible wine consumption at Franchthi Cave in Greece. 9th millennium BCE: The earliest domesticated fruit was the fig tree, 8th millennium BCE: The domestication of rice and barley, crops used for the production of fermented alcohol, occurred about 10,000 years ago. Production Alcoholic substances have intoxicating, mind-altering properties that might have been restricted to elites and religious specialists, but they were also used in the maintenance of social cohesion in the context of feasting available to everyone in a community.  Some herb-based beverages may have been used for medicinal purposes as well. 7000 BCE: The earliest evidence of wine production comes from jars at the Neolithic site of Jiahu in China, where residue analysis has identified a fermented concoction of rice, honey and fruit. 5400–5000 BCE: Based on the recovery of tartaric acid in ceramic vessels, people produced resinated wine, such as that on a fairly large scale at Hajji Firuz Tepe, Iran. 4400–4000 BCE: Grape pips, empty grape skins, and two-handled cups at the Greek site of Dikili Tash are the earliest evidence for wine production in the Aegean Sea region. 4000 BCE: A platform for crushing grapes and a process to move crushed grapes to storage jars are evidence of wine production at the Armenian site of Areni-1. Ubaid Pottery from Susa, Iran, 4th millennium BCE, Musà ©e National de Cà ©ramique, Sà ªvres, France. Siren-Com 4th millennium BCE: By the beginning of the 4th millennium BCE, wine and beer were produced in many locations in Mesopotamia, Assyria and Anatolia (such as the Ubaid site of Tepe Gawra) and treated as a trade and elite luxury good. At the same time, Predynastic Egyptian tomb paintings and wine jars are evidence of the local production of herb-based beers. 3400–2500  BCE: The predynastic community of Hierankopolis in Egypt had a large number of barley- and wheat-based brewery installations. Alcohol as a Trade Good It is difficult to draw the line globally for the production of wine and beer explicitly for trade. It seems clear that alcohol was both an elite substance and one with ritual significance, and the liquids as well as the technology of making them was shared and traded across cultures fairly early on. 3150 BCE: One of the rooms of the tomb of Scorpion I, the earliest of the dynastic kings of Egypt, was stuffed with 700 jars believed to have been made and filled with wine in the Levant and shipped to the king for his consumption. 3300–1200 BCE: Wine consumption is in evidence, used in ritual and elite contexts in Early Bronze Age sites in Greece, including both Minoan and ​Mycenaean cultures. Fu Yi Gong wine vessel from the Late Shang Dynasty (13th–11th century BCE) at the Shanghai Museum, China. Tim Graham / Getty Images 1600–722 BCE: Cereal based alcohol are stored in sealed bronze vessels of Shang (ca. 1600-1046 BCE), and Western Zhou (ca. 1046-722 BCE) dynasties in China. 2000–1400 BCE: Textual evidence demonstrates that barley and rice beers, and others made from a variety of grasses, fruits and other substances, were produced in the Indian subcontinent at least as long ago as the Vedic period. 1700–1550 BC: Beer based on the locally domesticated sorghum grain is manufactured and becomes ritually important in the Kerma dynasty of the Kushite kingdom of present-day Sudan. 9th century BCE: Chicha beer, made from a combination of maize and fruit, is a significant part of feasting and status differentiation throughout South America.   8th century BCE: In his classic tales The Iliad and The Odyssey, Homer prominently mentions the wine of Pramnos. When [Circe] had got [the Argonauts] into her house, she set them upon benches and seats and mixed them a mess with cheese, honey, meal, and Pramnian wine, but she drugged it with wicked poisons to make them forget their homes, and when they had drunk she turned them into pigs by a stroke of her wand and shut them up in her pig-sties. Homer, The Odyssey, Book X 8th–5th centuries BCE: The Etruscans produce the first wines in Italy; according to Pliny the Elder, they practice wine blending and create a muscatel type beverage. 600 BCE: Marseilles is founded by the Greeks who brought wines and vines to the great port city in France.   Iron and Gold Drinking Horn of the Celtic Chieftain at Hochdorf, on display at Kunst der Kelten, Historisches Museum Bern. Rosemania 530–400 BCE: Grain beers and mead produced in central Europe, such as barley beer at Iron Age Hochdorf in what is today Germany. 500–400 BCE: Some scholars, such as F.R. Alchin, believe that the first distillation of alcohol might have occurred as early as this period in India and Pakistan. 425–400 BCE: Wine production at the Mediterranean port of Lattara in southern France marks the beginning of the wine industry in France. 4th century BCE: The Roman colony and competitor of Carthage in North Africa has an extensive trade network of wine (and other goods) all over the Mediterranean region, including a sweet wine made from sun-dried grapes.   4th century BCE: According to Plato, strict laws in Carthage forbid the drinking of wine for magistrates, jury members, councilors, soldiers, and ships pilots while on duty, and for slaves at any time.   Widespread Commercial Production The empires of Greece and Rome are largely responsible for the international commercialization of the trade in many different goods, and specifically in the production of alcoholic beverages. 1st–2nd centuries BCE: The Mediterranean wine trade explodes, bolstered by the Roman empire. 150 BCE–350 CE: Distillation of alcohol is a common practice in in northwest Pakistan.   92 CE: Domitian forbids the planting of new vineyards in the provinces because the competition is killing the Italian market. Roman pavement mosaic depicting the god Bacchus at the Genazzano Villa in Rome, Antonine dynasty, 138–193 CE.   Werner Forman / Archive/Heritage Images / Getty Images 2nd century CE: Romans begin cultivating grapes and producing wine in Mosel valley of Germany and France becomes a major wine-producing region. 4th century CE: The process of distillation is (possibly re-)developed in Egypt and Arabia. 150 BCE–650 CE: Pulque, made from fermented agave, is used as a dietary supplement at the Mexican capital city of Teotihuacan. 300–800 CE: At Classic period Maya feasts, participants consume balche (made from honey and bark) and chicha (maize-based beer).   500–1000 CE: Chicha beer becomes a significant element of feasting for the Tiwanaku in South America, evidenced in part by the classic kero form of flared drinking goblet.   13th century CE: Pulque, an alcoholic beverage made from fermented agave, is part of the Aztec state in Mexico. 16th century CE: Production of wine in Europe moves from monasteries to merchants. Selected Sources Anderson, Peter. Global Use of Alcohol, Drugs . Drug 25.6 (2006): 489–502. Print.and andTobacco Alcohol ReviewDietler, Michael. Alcohol: Anthropological/Archaeological Perspectives. Annual Review of Anthropology 35.1 (2006): 229–49. Print.McGovern, Patrick E. Uncorking the Past: The Quest for Beer, Wine and Other Alcoholic Beverages. Berkeley: University of California Press, 2009. Print.McGovern, Patrick E., Stuart J. Fleming, and Solomon H. Katz, eds. The Origins and Ancient History of Wine. Philadelphia: The University of Pennsylvania Museum of Archaeology and Anthropology, 2005. Print.McGovern, Patrick E., et al. Fermented Beverages of Pre- and Proto-Historic China. Proceedings of the National Academy of Sciences 101.51 (2004): 17593–98. Print.Meussdoerffer, Franz G. A Comprehensive History of Beer Brewing. Handbook of Brewing. Wiley-VCH Verlag GmbH Co. KGaA, 2009. 1–42. Print.Stika, Hans-Peter. Beer in Prehistoric Europe. Liquid Bread: Beer and Brewi ng in Cross-Cultural Perspective. Eds. Schiefenhovel, Wulf and Helen Macbeth. Vol. 7. The Anthropology of Food and Nutrition. New York: Berghahn Books, 2011. 55–62. Print. Surico, Giuseppe. The Grapevine and Wine Production through the Ages. Phytopathologia Mediterranea 39.1 (2000): 3–10. Print.

Provide a concise account of the fundamental legal, ethical and Essay

Provide a concise account of the fundamental legal, ethical and professional practice aspects of nursing drug administration - Essay Example The safe and efficient administration of medication is one of the key responsibilities of the professional nurse. The practice of drug administration involves providing the patient with a substance prescribed and intended for the diagnosis, treatment, or prevention of a medical illness or condition (Hopkins, 1999). Although, effective drug administration involves the actual and complete conveyance of a prescribed medication to the patient, however, there is wider set of practices required to achieve safe, effective patient outcomes and to prepare for and evaluate the outcome of medication administration (Potter and Anne, 1997; Taylor et al, 1997). Because nurses administer prescribed drugs directly to patients, they happen to be the last link in the safe and effective drug prescription and administration sequence. Increased acuity of the patient nurses have to serve and the apparent reduction in the volume of resources available to nurses to ensure safe and effective practice, have greatly complicated the role of the nurse in drug administration (Cook, 2002). The purpose of this paper is therefore, to examine the legal, ethical and professional requirements of safe nursing drug administration. According to the NMC Guidelines for the Administration of Medicines, administration of medicines is a vital part of the professional duty of the nurse. It is not, however, a function that can be carried out ‘mechanically’ or following orders, but should be seen as a task that must be carried out in strict compliance with the written prescription of a medical practitioner. More importantly, it is task that requires thought and the exercise of professional judgement (NMC, 2002:3). Drug administration play a crucial role in achieving positive patient outcomes and despite the complexities involved with safely administering medications to patients, the professional nurse is duty-bound to do everything within her professional capacity to ensure this. The NMC code of

Subsidence Coursework Example | Topics and Well Written Essays - 4000 words

Subsidence - Coursework Example The crystalline rocks in which most metals are mined have greater strength and are less likely to settle or collapse. Subsidence can also occur where underground water has dissolved subsurface materials or has been withdrawn by wells. Sinking caused by the caving in of underground mine workings. Subsidence can result in serious structural damage to buildings, roads, irrigation ditches, underground utilities and pipelines. It can disrupt and alter the flow of surface or underground water. Surface depressions created by subsidence may be filled in, only to sink further because the underground void has not been completely closed. Areas may appear to be free of subsidence for many years and then undergo renewed gradual or even drastic subsidence Weight, including surface developments such as roads, reservoirs, and buildings, and man-made vibrations from such activities as blasting, heavy truck or train traffic can accelerate the natural processes of subsidence. Fluctuations in the level of underground waters caused by pumping or by injecting fluids into the earth can initiate sinking to fill the empty space previously occupied by water or soluble minerals. In general, the type and severity of surface subsidence is governed by the amount ground surface and the location of removal or compression, and the geologic conditions of a particular site. Withdrawal of pore fluids, usually ground water, is a common cause of ground subsidence. Massive lowering of the groundwater table by "mining" of ground water* in a poorly consolidated aquifer results in subsidence of the ground surface. Hydrocompaction produces ground surface collapse from excessive wetting of certain low-density weak soils. This can occur in two general types of soil, a) wind deposited silts b) predominantly fine-grained colluvial soils. In either case, collapse occurs from excessive wetting of previously dry, collapsible soils. Wetting of these materials weakens the already weak or unstable soil structure, which undergoes internal collapse and densification (reduction of air voids). Densification of the weak soil column produces ground surface collapse and subsidence in the v icinity of excessive wetting. Removal of fine material by piping* is probably an additional factor in some cases of subsidence by wetting. Such excessive wetting can occur from irrigation, broken water lines, surface ponding, or drainage diversions. Dissolution of soluble rock or soil materials also results in ground subsidence. This occurs in areas underlain by highly soluble rock formations-especially gypsum (CaSo4. 2H2O), or halite (NaC1); and to lesser extent in limestone (CaCO3) materials. Removal of earth materials by water solution leads to surface collapse. Hydrologic factors that may cause the solution and removal of material may be natural or man-induced. Natural solution is the result of the normal hydrologic processes of downward percolation of surface water and/or lateral movement of ground water within the water table (either the main ground water table or a perched water table). Man-induced hydrologic changes or activities can have much the same effect on soluble eart h materials. Such activities include temporary or permanent stream channel changes, irrigation ditches, land irrigation leaking or broken pipes, temporary or perm

How the area of a wire affects the resistance in a circuit Essay Example for Free

How the area of a wire affects the resistance in a circuit Essay Electricity is conducted through a conductor. Resistance is the word used to describe the opposition between forces. The more free electrons there are, the better the conduction and the worse the resistance is. The more atoms vibrate, the more resistance there is. The free electrons are given energy, as a result they move and collide with the surrounding electrons. This happen throughout the whole wire. This is how the electricity is conducted. Resistance is the result of energy loss in form of heat. How do we measure it? V=I/R V=Voltage I =Current R=Resistance Ohms Law. This law states that the current through a metallic conductor (wire) at a constant temperature is proportional to the potential difference (Voltage). Therefore the Voltage and Current is constant. If the resistance increases the temperature increases, so it stays constant. At higher temperatures the particles move more quickly, increasing the collision of the free electrons. Possible Input Variables Wire area Wire thickness Wire length Applied voltage Material Taught connections Cross-sectional shape Insulated Density of wire Coiled or not Temperature Preliminary Experiments. Easy to measure? Easy to change Wire area V V Wire thickness X X Wire length V V Applied voltage V V Material X V Taught connections X X Cross-sectional shape X X Insulated X V Density of wire V X Coiled or not V V Temperature V V Applied I or V by a double cell which is measured by digital volt and ammeter. I will find out the Resistance by the formula using R=V/I. Wire area. It is difficult to change the area. A possible solution would be to add wires and twist them together. Coiled or not? It has not got an obvious affect. The Voltage and Current didnt increase or decrease. Temperature. My idea was to set up a water bath to keep the wire at a same temperature at every point. I would experiment with temperatures from 20? C-100 (room temperature to the boiling point of water) Wire length. Is very easy to set up. There is a very large range of results. Chosen Input variable I chose wire area as my variable because it is has a better variety of results. I will have 8 wires with the same cross sectional area. It would be to expensive using different cross sectional sizes of wire. I will put the wire parallel to each other an twist them add the end to increase the area of the wire. My chosen output variable is resistance because that is what I am looking for in the wire. Fair Test In the experiment I am not going to change anything ( wire length and applied voltage). The only thing I will change is the area of the wire (input variable). I will use the same equipment throughout the test, to make sure it is a fair test. If I would use different equipment it may give me different readings. I am using a safety resistor, so that the current is the same and that the wire will not overheat. It would not be a fair test if the wire would heat because it would give my different sets of results at different temperatures. It could also be a safety hazard if the wire overheats. Method Cut eight wires of the same cross sectional area in 35cm length (only 30cm of wire measured because I have to attach crocodile clips on each side   The equipment is as following: 2 cell Battery Ammeter+ Voltmeter Safety Resistor 8 wires (35cm) 2 crocodile clips   My circuit will look as following:   Let electricity pass through the circuit and note down the readings of the ammeter and voltmeter. Add more wires to the circuit and continue as planned   Make three sets of results through an accurate experiment Prediction I will expect that if the area of the wire increases the resistance will decrease. This can be proven by background physics of the past. Observation Test Results Nr. of wires   This graph shows the voltages I measured Nr. of wires This graph shows the Current I measured Nr. of wires R1 R2 R3 Rave Area m^2 1/Area   This graph shows me the resistance and resistance average I have worked out. It also includes the formulas for the Area and 1/Area My Graphs are on a separate sheet of graph paper. Analysis My graph shows me that if I increase the area the resistance decreases. I have plotted two graphs to give me a wider range of results and averages in different areas (1/Area and Area m^2). My Area graph looks like a y =1/X graph X Y 1 1 2 0. 5 3 0. 333 4 0. 25 To reassure this I have plotted an average 1/Area. If it is correct then I should get a straight line. When I plotted the graph I had a straight line. This tells me that the average is proportional to 1/Area i. e. Rave ? 1/Area. The slope is: y/x= 10. 5/16= 0. 66 ? /mi I am ignoring the offset on my 1/Area graph This experiment shows me that resistance is definitely affected by the area of the wire. Looking at my background physics it has worked out like resistors on a parallel circuit. When attaching another wire to the experiment it acts like adding another parallel resistor in a parallel circuit. So if the area of the wire increases the resistance decreases. Also I have learned if the voltage goes down the resistance goes up Evaluation I found this experiment easy to do. I had no anomalies on my graph. This means that the points I have plotted are all in a acceptable arrangement. There were no experimental caused by a faulty connection. There were no safety hazards and the experiment was safe to do.

Conceptual and Historical Issues in Psychology Essay -- Psychology

For a long time in history, studies of history of psychology have been done in three distinct ways. These domains were as follows: consciousness, psyche, behavior and mental life but every case stood on its own. Psychology was in this case the knowledge domain. Moreover, psychology was composed of various accounts. There was also the case of the society that was composed of views of the world or culture or industrialization. Although the history between these disciplines is not viewed sometimes, there are social aspects that are studied on how they are related to psychology. The often asked question is the relationship between the theories of psychology and its application to human life for instance, individual life, mental life and subjectivity. Presently, efforts by writers to separate the three categories have seen light. Psychology itself cannot exist without a society which supports all its facts. Moreover, psychological object cannot be taken as independent, given, discovered b ut that which is discovered and comes before knowledge. Psychology can hence be seen in two perspectives: as a discipline and as a subject of human. A conclusion can be made that psychology exists in a domain that is constructed. This is contrary to science domain where truth is constructed. Introduction Science employs an approach of empiricism. This approach states that our senses are the only place from which knowledge originates. This is in contrary to knowledge view that exists that it could be acquired purely by logical argument and reasoning. Hence empiricism views knowledge to be based on experience. Empiricism through gain of knowledge via experience came to be an approach of science and influenced greatly chemistry and physics d... ... Scientific thought on the other hand, goes ahead to justify every observation by mere experimentation. With time it is found out that there an implication that the outcome of the experiments has on judgment because many arguments can be correct till proven right. Another example is on statistics where it is implicated in relationships. Works Cited McLeod, S. A. (2008). Simply Psychology; Psychology as a Science G. Bachelard (1984).The New Scientific Spirit, tr. Arthur Goldhammer, Boston, Beacon Press K. Danziger (1990).Constructing the Subject, Cambridge: Cambridge U. P K. Gergen(1985). The social constructionist movement in modern psychology, American Psychologist Hacking (1990).The Taming of Chance, Cambridge, Cambridge University Press. P. Heelas and A. Lock (1981).Indigenous Psychologies: The Anthropology of the Self, London, Academic Press