The Issue of Human Cloning Essay Example for Free

The Issue of Human Cloning Essay INTRODUCTION Human cloning has been a favorite subject in science fiction stories, but has in recent years, it has become front page news. Anytime that a new scientific debate is born, many details about the topic itself is muddled with many inaccuracies. The problem is: do people understand enough of the science to predict whether cloning will be acceptable or not ethically and/or legally? Does it make sense to bring new people in the world whose origin is drastically different than the majority of people? This short review will focus first on arguments for cloning human beings based on scientific arguments and second on arguments against human cloning from the book by Leon Kass â€Å"The Ethics of Human Cloning. † REPRODUCTIVE AND RESEARCH CLONING Cloning is done in adult animals by somatic cell nuclear transfer. In the case of sheep like Dolly, the nucleus of a cell from a sheep is placed inside the cell of another sheep that has been emptied from its nucleus. However, contrary to the popular belief, the cloned sheep will not be 100% genetically identical to the donor sheep. The enucleated cell still has some DNA inside in organelles like the mitochondria that will be different than the donor’s DNA. The main arguments for cloning deal with the potential medical as well as scientific benefits that would be conferred upon humanity if adult humans could be cloned. The first reason is that cloning humans would bring forth medical breakthroughs for curing diseases like cancer. The rationale is that cloning involved in the differentiation of a cell may be an advantage that could help in the comprehension of how a cell differentiates and divides. Cancerous cells are multiplying without restraints since the cellular mechanisms for regulating cell division and cell growth are non-functional. Usually, unrestrained division and growth in normal cells do not continue because the cell has safety mechanisms that will induce death or apoptosis to stop this uncontrollable process. Other ideas about the benefit of cloning are cloning organs that could replace defective ones like heart, kidneys, and liver. This type of cloning is called research cloning contrasting with reproductive cloning. Another argument deals with infertility and reproduction. Many people cannot have children. Reproductive cloning would not only give them a child, but an ideal child in terms of genomic inheritance, implying that a clone could have its genome altered based on the parent’s disease history. This would guarantee a healthy child or some kind of twin to the parent. In essence, identical twins are clones of each other since their genome is identical. Cloning also happens all the time in nature. So, why not in humans too whenever it is wanted? ARGUMENTS AGAINST CLONING Leon Kass in his book â€Å"The Ethics of Human Cloning† analyzes the reasons why human cloning should never be used in our society. Dr. Kass expresses a fundamental distrust of human cloning based on the fact that human intervention is involved in the process. In effect, he draws a parallel between artificial insemination and cloning since both are in vitro processes in the beginning, being transferred to a host in vivo at the end. The problem with â€Å"human hands† is that ‘good intentions pave the way to Hell’ as the saying goes. We can start as wanting the best child, better health, and more intelligence, but in any case, we are not very far from eugenics. Eugenics have a strong opposition because it relies on selecting people based on genetic traits that are changed in order to bring about a specific characteristic in an individual. Eugenics may be the start of a socially unacceptable bias or discrimination based on the fact that the majority of mankind is naturally not fit genetically to qualify as persons almost physically and mentally perfect. In a world where only the most perfect humans would be chosen to survive, no room would be left for ‘inferior’ people. A past historical event connected with this idea is the Holocaust during which, people were gassed in order to get rid of their races or experimented upon in order to find out what physical perfection meant in order to improve the superior race. In addition, Dr. Kass deals with the traditional way of reproduction. Humans reproduce by sexual reproduction and have done so since the beginning of times. Since the announcement about cloning the first sheep, people have been upset about it because they feel that developing the technique further opens the proverbial Pandora’s Box. Will cloning affect our human dignity or our human nature? Moreover, based on the assumption that cloning humans would be accepted, he asks what status a clone would hold in our society. Past historical experiences with slavery and racism have troubled society till today. In fact, the general human population alienates who is different. It has been our nature people to ostracize others who are not judged normal. What would be the place of a clone in our society? What about a social status? What about legal perspectives concerning the rights and connections to their family? Dr. Kass also explains that science has more and more meddled with human reproduction, which he finds troublesome. He believes that there is an excess of consideration of what science in general can do to solve problems. In fact, by remedying one problem, it always creates new ones. In conclusion, cloning seems to possess multiple challenges to its establishment in society. The majority of humans feel that it is an attack on their human nature (reproduction and morality), which they hold sacred. The supporters of cloning are mainly concerned with what cloning can do for mankind in terms of acquiring scientific knowledge to cure diseases like cancer. Time will tell if cloning will bring doom or a better lot in life for humans.

The WWW and Problem Based Learning in Introductory Philosophy :: Education Teaching Essays

The WWW and Problem Based Learning in Introductory Philosophy ABSTRACT: This essay explains how problem-based learning and the World Wide Web (WWW) may be used in collaboration to shift student learning experiences in dramatic ways and to encounter the tasks and concerns of philosophy. We will provide a guided tour of the web site and the problems used in the course, and will describe how these pedagogical strategies may be used to complement traditional classroom venues without making a commitment to offering a course completely on-line for distance learning scenarios. Problem-based learning will also be described and its importance to philosophical instruction will be emphasized. We argue that teaching philosophy by means of problems is more philosophically sound than taking a discrete topical or textual approach. Challenges to this pedagogy are uncovered and discussed. This paper will focus on two significant instructional methods, problem based learning and the use of the web as a teaching tool. It will provide details of the ways in which these two methods have been merged in an Introductory Philosophy class. We will be demonstrating the navigation of our Introduction to Philosophy course web site. I. Problem Based Learning Problem-Based Learning (PBL) is a method of teaching and learning that stresses problem solving activities as a means to encountering and applying knowledge. (Barrows, 1984) It develops out of a strong concern that traditional education stresses the acquisition of factual knowledge without long term retention of that information, the ability to apply the material, the skill to think critically, or the understanding of the context in which knowledge develops and relates. (Norman, 1988, Bridges, 1992, Walton and Matthews, 1989).PBL uses a set of problems - simulations, ethical dilemmas, case studies, medical diagnoses or decisions, legal disputes, public policy issues - as the framework for student learning. The closer the problem is to a real life, relevant problem, the better it functions as a learning motivator. (Bridges, 1992). In traditional lecture and discussion format classes, the instructor introduces the material that he/she deems appropriate and then tests the students knowl edge of the material. In PBL, the student is initially confronted with a problem that requires a solution. The problem drives the student assignments and learning tasks. It is the avenue through which students become acquainted with the material. Barbara Duch says "In a traditional science class, learning tends to proceed from the abstract to the concrete, with concepts being introduced first, followed by an application problem.

Digital Modulation Techniques

LOVELY PROFESSIONAL UNIVERSITY TERM PAPER Topic: Digital Modulation Techniques Course code: ELE102 Course title: Electrical science-II Submitted to:Submitted by: Subrahmanyam Tanala Sirvishwajeet kumar Sec:K1901 Roll:B57 Contents INTRODUCTION †¢ 1 Aim †¢ 2 Analog modulation methods †¢ 3 Digital modulation methods o 3. 1 Fundamental digital modulation methods o 3. 2 Modulator and detector principles of operation o 3. 3 List of common digital modulation techniques †¢ 4 Digital baseband modulation or line coding †¢ 5 Pulse modulation methods †¢ 6 Miscellaneous modulation techniques 7 References INTRODUCTION In electronics, modulation is the process of varying one or more properties of a high frequency periodic waveform, called the carrier signal, with respect to a modulating signal. This is done in a similar fashion as a musician may modulate a tone (a periodic waveform) from a musical instrument by varying its volume, timing and pitch. The three key parame ters of a periodic waveform are its amplitude (â€Å"volume†), its phase (â€Å"timing†) and its frequency (â€Å"pitch†), all of which can be modified in accordance with a low frequency signal to obtain the modulated signal.Typically a high-frequency sinusoid waveform is used as carrier signal, but a square wave pulse train may also occur. Aim The aim of digital modulation is to transfer a digital bit stream over an analog passband channel, for example over the public switched telephone network (where a bandpass filter limits the frequency range to between 300 and 3400 Hz), or over a limited radio frequency band. The aim of analog modulation is to transfer an analog baseband (or lowpass) signal, for example an audio signal or TV signal, over an analog passband channel, for example a limited radio frequency band or a cable TV network channel. | 2 Analog modulation methods In analog modulation, the modulation is applied continuously in response to the analog info rmation signal. [pic] [pic] A low-frequency message signal (top) may be carried by an AM or FM radio wave. Common analog modulation techniques are: †¢ Amplitude modulation (AM) (here the amplitude of the carrier signal is varied in accordance to the instantaneous amplitude of the modulating signal) o Double-sideband modulation (DSB) ? Double-sideband modulation with carrier (DSB-WC) (used on the AM radio broadcasting band) ?Double-sideband suppressed-carrier transmission (DSB-SC) ? Double-sideband reduced carrier transmission (DSB-RC) o Single-sideband modulation (SSB, or SSB-AM), †¢ Angle modulation o Frequency modulation (FM) (here the frequency of the carrier signal is varied in accordance to the instantaneous amplitude of the modulating signal) o Phase modulation (PM) (here the phase shift of the carrier signal is varied in accordance to the instantaneous amplitude of the modulating signal) The accompanying figure shows the results of (amplitude-)modulating a signal on to a carrier (both of which are sine waves).At any point along the y-axis, the amplitude of the modulated signal is equal to the sum of the carrier signal and the modulating signal amplitudes. [pic] [pic] Simple example of amplitude modulation. 3 Digital modulation methods In digital modulation, an analog carrier signal is modulated by a digital bit stream. Digital modulation methods can be considered as digital-to-analog conversion, and the corresponding demodulation or detection as analog-to-digital conversion. The changes in the carrier signal are chosen from a finite number of M alternative symbols (the modulation alphabet). [pic] [pic] Schematic of 4 baud (8 bps) data link.A simple example: A telephone line is designed for transferring audible sounds, for example tones, and not digital bits (zeros and ones). Computers may however communicate over a telephone line by means of modems, which are representing the digital bits by tones, called symbols. If there are four alternative symbols (corresponding to a musical instrument that can generate four different tones, one at a time), the first symbol may represent the bit sequence 00, the second 01, the third 10 and the fourth 11. If the modem plays a melody consisting of 1000 tones per second, the symbol rate is 1000 symbols/second, or baud.Since each tone (i. e. , symbol) represents a message consisting of two digital bits in this example, the bit rate is twice the symbol rate, i. e. 2000 bits per second. This is similar to the technique used by dialup modems as opposed to DSL modems. . According to one definition of digital signal, the modulated signal is a digital signal, and according to another definition, the modulation is a form of digital-to-analog conversion. Most textbooks would consider digital modulation schemes as a form of digital transmission, synonymous to data transmission; very few would consider it as analog transmission. . 1 Fundamental digital modulation methods The most fundamental digita l modulation techniques are based on keying: †¢ In the case of PSK (phase-shift keying), a finite number of phases are used. †¢ In the case of FSK (frequency-shift keying), a finite number of frequencies are used. †¢ In the case of ASK (amplitude-shift keying), a finite number of amplitudes are used. †¢ In the case of QAM (quadrature amplitude modulation), a finite number of at least two phases, and at least two amplitudes are used. FSK The two binary states, logic 0 (low) and 1 (high), are each represented by an analogue waveform.Logic 0 is represented by a wave at a specific frequency, and logic 1 is represented by a wave at a different frequency. Below shows the basic representation. [pic]  Ã‚  Ã‚  [pic] With binary FSK, the centre or carrier frequency is shifted by the binary input data. Thus the input and output rates of change are equal and therefore the bit rate and baud rate equal. The frequency of the carrier is changed as a function of the modulating signal (data), which is being transmitted. Amplitude remains unchanged. Two fixed-amplitude carriers are used, one for a binary zero, the other for a binary one. Uses of FSK.Today FSK Modems are used for short haul data communication over private lines or any dedicated wire pair. These are many used for communication between industrial applications like railroad signalling controls and mobile robotic equipment. The short haul modem offers the following specs; – Speeds of up to 9600 bps – Full-duplex or half duplex operation. – Distance up to 9. 5 miles In the past FSK was used in the Bell 103 and Bell 202. These were the first data modem but due to their low bit rate there not being used any more. The Bell 103 had a data rate of only 300 bauds. This modem was predominant until the early 1980s.Phase Shift Keying – PSK Phase shift keying (PSK) is a method of transmitting and receiving digital signals in which the phase of a transmitted signal is varied to c onvey information. The simplest form of PSK has only two phases, 0 and 1. It is therefore a type of ASK with  ¦(t) taking the values -1 or 1, and its bandwidth is the same as that of ASK. The digital signal is broken up time wise into individual bits (binary digits). The state of each bit is determined according to the state of the preceding bit. If the phase of the wave does not change, then the signal state stays the same (low or high).If the phase of the wave changes by 180 degrees, that is, if the phase reverses, then the signal state changes (from low to high or from high to low) If the phase of the wave changes by 180 degrees, that is, if the phase reverses, then the signal state changes (from low to high or from high to low). Because there are two possible wave phases, this form of PSK is sometimes called bi-phase modulation. If two or more of the same logic level are received in secession the frequency will remain the same until the logic level changes. Variants of PSK. -B inary Phase Shift Keying (BPSK): – Use alternative sine wave phase to encode bits Simple to implement, inefficient use of bandwidth Binary Phase Shift Keying (BPSK) demonstrates better performance than ASK and FSK. PSK can be expanded to a M-array scheme, employing multiple phases and amplitudes as different states. Phase Shift Keying – PSK Phase shift keying (PSK) is a method of transmitting and receiving digital signals in which the phase of a transmitted signal is varied to convey information. The simplest form of PSK has only two phases, 0 and 1. It is therefore a type of ASK with  ¦(t) taking the values -1 or 1, and its bandwidth is the same as that of ASK.The digital signal is broken up time wise into individual bits (binary digits). The state of each bit is determined according to the state of the preceding bit. If the phase of the wave does not change, then the signal state stays the same (low or high). If the phase of the wave changes by 180 degrees, that is , if the phase reverses, then the signal state changes (from low to high or from high to low) If the phase of the wave changes by 180 degrees, that is, if the phase reverses, then the signal state changes (from low to high or from high to low).Because there are two possible wave phases, this form of PSK is sometimes called bi-phase modulation. If two or more of the same logic level are received in secession the frequency will remain the same until the logic level changes. Variants of PSK. a)Binary Phase Shift Keying (BPSK): – Use alternative sine wave phase to encode bits – Simple to implement, inefficient use of bandwidth [pic] Binary Phase Shift Keying (BPSK) demonstrates better performance than ASK and FSK. PSK can be expanded to a M-array scheme, employing multiple phases and amplitudes as different states.Filtering can be employed to avoid spectral spreading. b)Quadrature Phase Shift Keying (QPSK): – Multilevel modulation technique: 2 bits per symbol â€⠀œ More spectrally efficient, more complex receiver [pic][pic][pic] Quadrature Phase Shift Keying is effectively two independent BPSK systems (I and Q), and therefore exhibits the same performance but twice the bandwidth efficiency. Output waveform is sum of modulated;  ± Cosine and  ± Sine wave. Variants of QPSK [pic] – Conventional QPSK has transitions through zero (i. e.. 180o phase transition). Highly linear amplifier required. In Offset QPSK, the transitions on the I and Q channels are staggered. Phase transitions are therefore limited to 90o – ? /4-QPSK the set of constellation points are toggled each symbol, so transitions through zero cannot occur. This scheme produces the lowest envelope variations. Uses of PSK Binary Phase Shift Keying (BPSK) – BPSK is mainly used in deep space telemetry and also cable modems Quadrature Phase Shift Keying (QPSK) and it Variants Satellites – CDMA, (Code-Division Multiple Access) refers to any of several proto cols used in so-called second-generation (2G) and third-generation (3G) wireless communications. TETRA, Terrestrial Trunked Radio) is a set of standards developed by the European Telecommunications Standardization Institute (ETSI) that describes a common mobile radio communications infrastructure throughout Europe This infrastructure is targeted primarily at the mobile radio needs of public safety groups (such as police and fire departments), utility companies, and other enterprises that provide voice and data communications services. LMDS, (Local Multipoint Distribution System) is a system for broadband microwave wireless transmission direct from a local antenna to homes and businesses within a line-of-sight radius, a solution to the so-called last-mile technology problem of economically bringing high-bandwidth services to users. . 3. 3 List of common digital modulation techniques The most common digital modulation techniques are: †¢ Phase-shift keying (PSK): o Binary PSK (BPS K), using M=2 symbols Quadrature PSK (QPSK), using M=4 symbols o 8PSK, using M=8 symbols o 16PSK, using M=16 symbols o Differential PSK (DPSK) o Differential QPSK (DQPSK) o Offset QPSK (OQPSK) o ? /4–QPSK †¢ Frequency-shift keying (FSK): o Audio frequency-shift keying (AFSK) o Multi-frequency shift keying (M-ary FSK or MFSK) o Dual-tone multi-frequency (DTMF) o Continuous-phase frequency-shift keying (CPFSK) †¢ Amplitude-shift keying (ASK) †¢ On-off keying (OOK), the most common ASK form M-ary vestigial sideband modulation, for example 8VSB †¢ Quadrature amplitude modulation (QAM) – a combination of PSK and ASK: o Polar modulation like QAM a combination of PSK and ASK. [citation needed] †¢ Continuous phase modulation (CPM) methods: o Minimum-shift keying (MSK) o Gaussian minimum-shift keying (GMSK) †¢ Orthogonal frequency-division multiplexing (OFDM) modulation: o discrete multitone (DMT) – including adaptive modulation and bit-load ing. †¢ Wavelet modulation Miscellaneous modulation techniques †¢ The use of on-off keying to transmit Morse code at radio frequencies is known as continuous wave (CW) operation. †¢ Adaptive modulation †¢ Space modulation A method whereby signals are modulated within airspace, such as that used in Instrument landing systems. 7 REFRENCES J. R. Barry, E. A. Lee, D. G. Messerschmidt, Digital Communication, Kluwer Academic Publishers, 2004. www. wikipedia. org Communication systems (Simon Haykin), Wiley India

The Presidents of Ireland 1938 Until Present