Traditional or Logical Dead Poets Society Essay Example for Free

Traditional or Logical Dead Poets Society Essay In the movie Dead Poets Society, there are many disagreements on how the children should learn. The issue being discussed was everyone believed that the traditional way of teaching was a superior technique of education and the school did not want to change. Once Mr. Keating came into the picture and started teaching in a new way, administrators believed he was in the wrong by the way he taught. If the opinion of the students mattered then Mr. Keating’s way was the best. Not one of the students were ever allowed to live their life to the fullest but Keating showed the students how to have fun but still learn. This all came to an end when one student took his own life and Mr. Keating’s free ways of thinking were blamed. Although the school, Welton Academy, believed the traditional method was best, Mr. Keating’s method of teaching helped his students make their own decisions and do things for themselves. Mr. Keating’s way of teaching inspired the students to live their lives to the fullest, look at everything in different ways, and prepared them for the future by teaching them to make their own decisions and learn to do things their selves. Living their life to the fullest potential is one of the most important things that a person needs to focus on. A person needs to appreciate what they have been given and take advantage of it because they don’t know when it might be their last chance to do the activities that they want to do. Live it up and do your best because at the end of your life you should have no regrets. Living your life to the fullest a great thing to do. Mr. Keating had many different methods of teaching that helped better the students in life and make their own decisions. One of Mr. Keating’s methods of teaching was to show the kids to look at everything in more than one view. He told the all of his students to stand on top of the desk to get the best look of the room because it gives a fuller view of everything that needs to be taken in. Seeing things in different ways helps relate to the boys that everyone else may see the world in a different way. The bigger picture is not necessarily the best picture other people see things in diverse ways and take in the beauty in their own manner. Mr. Keating’s way of teaching is more inspiring to students because it varies in different learning environments. The technique teaches the students to think in new ways and helps them understand the teaching better. Also, learning new things in different places might add some interest to the subject, which may help raise grades and add a chance for the students to think for themselves. Every person is entitled to a way of learning that will better them in the long run. Understanding the way Mr. Keating’s teaches encourages the students of Welton Academy to live their lives to its fullest potential. Mr. Keating showed the students that it is alright to think for their selves make their own decisions. Most of the boys followed the decisions of their parents or had to follow in their brothers footsteps. The boys chose to make their own Dead Poets Society. Neil, one of the boys decided to join a play and Todd decided to throw his birthday present off the roof because he did not like it. All the boys did not know how to take charge until Mr. Keating taught them the phrase Carpe Diem which means seize the day. Some of the boys just blew it off and could care less and some boys took it to heart. As a result of one of the boys taking Carpe Diem to far one of the students ended up taking their own life. Although the movie ended tragically, the administrators blamed Mr. Keating. All of the boys just sat back and let everyone blame Mr. Keating. Todd Anderson stood up and used what Mr. Keating taught him and told the administrators that is was not Mr. Keating’s fault and that it was Neil’s choice.

Two Object Oriented Methodologies Booch And Rambaugh Information Technology Essay

Two Object Oriented Methodologies Booch And Rambaugh Information Technology Essay In this paper Object-oriented System development methodologies i-e Booch, Rambaugh, are reviewed and compared with each other with a focus on their development processes. We have developed a framework based on a set of criteria to compare the two methods. The aim of this comparison is to better understand the core philosophies and processes of each method, and internal activities that each method provides. The aim of this descriptions and comparisons are not to criticize the philosophies of theses methodologies, but to give a description of the two methodologies that will facilitate the readers to better understand each methodology, and to what extent the two methodologies are object oriented. And also this comparison provides an ease in selecting and evaluating each methodologys process. (doc1)The software engineering field has been evolving over the past thirty years, but it has never completely solved the software crisis. Software development methodologies, as an essential element of the discipline of software engineering, have also evolved from the shallow and informal methodologies of the late 1960s to the object-oriented methodologies of the 1990s and the new millennium (doc1). There is a rapid development in the object oriented paradigm during the past years and the important reasons for such rapidness are that the real world applications are modeled in a better way as well as the object oriented paradigm enables the reusability of different artifacts during the development of a software system. Object oriented system development approach facilitates the re-use of software components. A system developed with Object Oriented Methodology (OOM) on component basis can re-use the existing components effectively, and as well as its components can be shared by some other systems too. One can achieve higher productivity, better quality and low maintenance cost by adopting the OOM. Since, the object-oriented methodologies (OOM) are still growing and continue to evolve, and there are a number of popular OOMs circulating around, but none of them is widely accepted. The software community is yet not agreed upon several fundamental issues. (1) A methodology is a systematic collection of techniques guidelines for how to build, buy, maintain and/or enhance software products. A methodology provides a basis for communication, a toolkit of techniques and a basis for repeatable, reliable software engineering. The term, method, refers to an approach to activities generally adhering to common principles [14]. Object-oriented software development methodologies, starts from the appearance of hybrid methodologies, then move to seminal methodologies, and the development of integrated (third-generation/heavyweight) methodologies and their agile (lightweight) counterparts. The following are the categories of Object oriented methodologies [15]: Seminal: Shlaer-Mellor, Coad-Yourdon, RDD, Booch, OMT, OSA, OOSE, BON,Hodge-Mock, Syntropy, Fusion; Integrated: OPM, Catalysis, OPEN, RUP/USDP, EUP, FOOM; Agile: DSDM, Scrum, XP, ASD, dX, Crystal, FDD; Although the promises, that the object-oriented software development provides, are based on solid grounds but still there is a confusion among the organization on when and how to invest in this new technology and also whether to invest or not. One of the reason for such confusion is that a great number of methodologies have been evolved during the last years. The other reason for confusion is closely related to the attractiveness of object-oriented software: Many vendors sticks the label object-oriented to their products without delivering important features as King (1989, p. 24) states: If I were trying to sell (my cat) I would argue that he is object-oriented. Research Problem The research question we are going to answer is: To what extent the two Object Oriented Methodologies: Booch and Rambaugh methodologies are Object Oriented and to what extent the methodologies help the software development organizations?. The selection cretaria for the the above two OOM is mentioned in the section 1.4.2. Since the object oriented paradigm evolved in different areas of the software development simultaneously, therefore fundamental concepts were different in different methodologies and were not completely standardized. Each OOM developed in a particular software domain such as real time systems and Information systems, although some cross-over exists in some concepts among the methodologies. Therefore, some methodologies are best in the development of applications that belong to the domain for which the methodology is evolved, while other can be used more generally. Even though OOM that evolved in the same domain may differ enough in different concepts such as process and notation and as a result can effect the software engineering goals. Motivation In the recent years, an overwhelming popularity of object oriented analysis and design has been witnessed. This phenomenon is evidenced by the number of papers and articles that are published in various conference proceedings, journals, books, and other forms. But There are still a large part of the business world that uses traditional software development approach for applications development. And on the technology side, there is an extensive development in the area of Object-Oriented technologies that promises better quality and productivity through reusability, and also encourages team work. The following observation is made in a survey [] about the organizations that uses OOM, performed by Sumit: A recent survey of IS managers revealed that 39% of organizations have adopted OO technology in some form. Nonetheless, OO development methodologies are used in only 5% of IS projects are developed in OO methodologies (Glass, 1999). For a specific application the first task is to decide which methodology is most appropriate for its development. Sometimes we may have to adapt different methodologies. Therefore an organization, that wants to switch to object oriented technology, faces one important question: which OOM is appropriate and should be chosen? A systematic comparison of available OOMs can answer such a question in a better way before selecting one of them. There are number of papers and articles that compare different aspects of the OOMs such as the reusability, documentation and others. So there is a need for the comparison which considers their system development core philosophy including all the concepts that methodologies provide in their development process. Unfortunately, the comparison of these methodologies is complicated because each OOM has its own set of definitions of the techniques, concepts, notations and are composed of informal descriptions, therefore the comparison of the methodologies depends largely on the interpretations and perceptions of the person who performs the comparison[10]. Such a comparison facilitate the organization that are developing software with traditional approach and now these organizations want to switch from the traditional software development approach to object oriented approach.. We also want to improve the understanding of these methodologies through this comparison, and to provide an ease in selecting, and evaluating the methodologies. The other purpose is to provide knowledge to the individuals that are interested to get the knowledge about object-oriented concepts, to what extent the two methods are object oriented, and how they relate to one another. Such interest in some cases is academic (e.g., students). Similarly individuals in companies or organizations want to evaluate and select a methodology to be used in software development process. We believe that sometime these groups are given short time and resources to make this decision, therefore comparisons like this will provide a shortcut means of selection. Research Methodology and comparison issues First we will review the existing software development methodologies (seminal methodology) that are object-oriented. We will study their system development processes to get a knowledge base about the object oriented technology. The purpose of this study is to understand their system development processes and internal activities involved in these development processes. Then we will review the two methods using a process-centered template, where we will summarize the two methodologies, and the activities and techniques discuss in the two methodologies will be highlighted. In the second step we will evaluate and compare Booch and Rumbaugh Object Oriented. We will use books, journals, proceedings, and internet sources as the data sources about the object oriented methodologies and ongoing research to gain the knowledge base. This report compares the two object oriented methodologies: Booch method and Rambaugh method, by considering their system development core philosophy. A research has been done in Hewlett Packard Laboratories by Arnold and his colleagues [1], in which several comparing criteria are defined in the form of questions for comparing Object oriented Methodologies. These comparing criteria are based on the concepts, notations, process, and pragmatics of the OOM methodology. Influenced by the above research, this report presents a framework to compare the two selected methodologies using the same set of criteria form the above research. The framework uses these set of comparing criteria for comparing the concepts, notations, process, and pragmatics of the two selected methodology which are defined in the section 1.5.1 under the heading of comparison variables. Using such framework helps us to avoid misunderstanding and misinterpretation of the two methods during the comparison process. Based on this framework, the two methods are extensively compared. The results are presented in a set of tables. Since the results are in tabular form so the similarities and differences as well as the strengths and weaknesses of the two methods can easily be seen. Comparison Variables As mentioned above, this report uses four main categories of the two methodologies in the comparison which are defined as follows: Concepts: Concepts are related to the conceptual underpinnings of the methodology that makes it object-oriented, and explians how the concepts such as object, class, state, inheritance, aggregation, and information hiding are defined and dealt by the methodology? Process: The methodology describes what steps to be taken and in what order to accomplish certain task in develoment process. How well the methodology specifies the process varies largly from methodology to methodology. Notation: The methodology describes tecniques (textual, and /or graphical) to capture and represent information within the development process. Some methodologies describe graphical techniques only, while others specify the form and content of whole documents. Pragmatics: The pragmatic criteria concentrate on nontechnical features. Pragmatics covers issues like needed resources, language suitability, learning of the CASE tools, required expertise, and domain applicability.(8) Comparison variables are listed in Table 1 under each category. The selection criterion for these variables is objectiveness. The aim of this report is to do the objective comparison of methodologies. That is, hard facts are produced by these variables about a methodology showing that a methodology either supports or does not support these variables. This selection criterion has one limitation. That is, no fine grained information regarding a variable is provided in this report for the comparison. Typically, the degree to which a methodology supports a variable is not answered in this comparison. In order to alleviate this shortfall for some variables, the report distinguishes explicit methodology support from implicit methodology support in the comparison and provide fine grained information if appropriate. The definitions of these variables in Table I are delayed until Section 3 when the selected OOADMs are compared. Table 1: Comparison variables Category Variables Concepts Class/Object, Abstract Classes, Meta-Classes, Encapsulation, Inheritance, Association, Aggregation, Methods/Messages, Type of Communications between objects and classes, Concurrency Process Development Process Deliverables, Development Context, Aspects of the Development Life-Cycle, Partitioning Mechanism, The Life-Cycle of the Methodologies Notations Static Concepts, Dynamic Concepts, Explicit Rules for Notations Symbols Pragmatics System Size, Programming Languages Support Selection of OOMs As mentioned above that this report compare the following two OOM for comparison. Object-Oriented Modeling and Techniques by J. Rumbaugh, et al. [Rumbaugh 91] Object-Oriented Analysis and Design by G. Booch [Booch 94] The selection of OOMs is based on three criteria. First the Object Oriented Methodologies (OOM) must be published in text book form so that adequate information is available for our comparison; which narrowed down our selection to those OOMs that are available in the text book form. Second the OOMs should be well-known and must be accepted by the software development community as real object-oriented methodologies. Third the methodologies must be supportred by CASE tools. The two OOM, selected in this report for camparison, fulfill and satisfy the three criteria [1, 10]. Both Booch, and Rumbaugh, which are the most widely used OOM, have evolved either from the real time domain or information processing domain and also are used in general. The two methodologies has gained significant attention so far in the software development community and are well documented at the same time. These criteria might exclude some well-known OOMs or recent developments in the OOM, but sufficiency, maturity and general acceptance of methodologies are the primary requirements for software development practice. Literature review Limitation This paper evaluates the aforementioned methods by scoring them against a set of criteria. It is not the goal of the paper to answer the question which one is the best? But rather to show the differences between methods and to allow conclusions be drawn as to their applicability. Remaining of report is divided into four sections. Section 2 provides a brief introduction of the two methodologies. Section 3 contains the comparison of the two methodologies. Section 4 presents the conclusion for the comparison of the two OOMs. Finally, section 5 contains the references to the literature used for this research. Brief introduction Of the Booch And Rambaugh (OMT) Methods Booch (1991, 1994) Booch introduced object oriented methodology in his book published in 1991. He was the first one to give the idea of the object-oriented approach in software development process, which he called system design [2][3]. He was popular at that for his landmark paper [Booch 1986] and for the work on Ada program design. He then introduced the analysis methodology to his design and extended his design model as a repeating process which he called The Micro Process) within a development process which is referred as The Macro Process. The macro process is shown in the figure 1 below as prescribed by Booch which is a self-iterative process Figure 1- The Macro Process -Booch [1994] These two processes are discussed in the next sections. The Macro Process The macro process consists of the following steps [2] [3] [4]. 1. Establish core requirements for software (conceptualization). 2. Develop a model of the systems desired behavior (analysis). 3. Create architecture for the implementation (design). 4. Evolve the implementation through successive refinements (evolution). 5. Post-delivery evolution management (maintenance). The Micro Process The micro process consists of the following activities as shown in figure 2 below [2] [3] [4]: The classes and objects are identified at a given abstraction level. Figure 2-The Micro Process Booch [1994] 2. Previously identified classes and objects meanings are established by defining the Semantics for every class and object, as well as the behavior of the system and its components are determined. 3. The interface of classes and objects as well as their implementation are specified. Decisions about the representation of the classes and objects are made in design model. Rambaugh OMT (1991) Rumbaugh introduced Object Modeling Technique (OMT) in 1991.OMT consists of following three major models and then it defines a method for integrating them [11] [12]. 1. The Object Model 2. The Dynamic Model 3. The Functional Model The object model In this model, Objects static structure and relationships among these objects are determined within a system. The following are the main concepts used in this model: object class operation attribute association aggregation Inheritance Dynamic model This model gives a description about the dynamics of the objects and their changes in states. This model shows the essential characteristics that change over time in a system by observing the objects behavior over time, and by exploring control and events flow among the objects. The control aspects of a system are specified and implemented in this model. The following are the main concepts in this model: state sub/super state event activity action Functional model This model shows information about the data flow within a system and the outside world. The following are then main concepts of this model: process data flow data store actor (source/sink) control flow OMT consists of five phases. 1. Analysis 2. System Design 3. Object Design 4. Implementation (coding) 5. Testing OMT processes considers the primary features in the first three phases of development (i-e Analysis, System Design and Object Design) and are explained in following sections. The following figure 3 shows these processes. Figure 3.-The OMT process- Derr [1995]. 1. Analysis this phase goal is to build a comprehensible and correct model according to the real world situation. The initial problem statement is developed from the requirements of the users and information that are provided by developers and managers. The analysis phase produces the following deliverables [11] [12]: Problem Statement Object Model, which consists of Object Model Diagram and data dictionary Dynamic Model, which consists of State Diagrams and Global Event Flow Diagram Functional Model, which consists of Data Flow Diagram and constraints 2. System design on the bases of architectural design of the system and problem domain, the system is partitioned into subsystems. The following are the system design phase deliverables: System Design Document: consists of architectural design of the system and high-level strategic decisions for implementing data stores in the form of data structures, files, and databases. 3. Object design based on the analysis model, the goal of this phase to provide Implementation details that include the domain infrastructure classes along with the internal objects needed for implementation. The following are the object design phase deliverables: Detailed Object Model Detailed Dynamic Model Detailed Functional Model 4. Implementation in this phase the system that is designed so far is translated into programming language code and hardware. 5. Test The entire System that is developed is verified in this phase. Testing includes system level and scenario based tests. Comparison Of Booch and Rambaugh methods The framework used in this paper is considering the following major areas of each methodology for comparison: Concepts Process Notations Pragmatics 3.1 Concepts A method to be consider as object oriented, it should support concepts that are related to the object oriented methologies. This comparison provides help in evaluating the method to the extent it is is object oriented. Therefore , in this paper we are comparing object oriented concepts of the two methodologies, Booch and Rambaugh, in the following categories. Concepts, such as Class, Object, etc. The relationships such as Inheritance and Aggregation Types of communications between objects and classes. Concurrency mechanisms Object is the fundamental concept of every object-oriented method, that must be supported by the method. An object encapsulates its internal state (or attributes) and provides a set of operations (methods/messeges) as an interface for manipulating the state. Whereas a class is a template which describes the attributes and interface of a set of objects. Object instances are produced by defining class variables.[5] Table 1 lists comparison of the object oreinted concepts that both methodology provides. A Y in the box for each concept represents that an artifact is provided by the coresponding methodology. Table 1. Object Oriented concepts Method Rumbaugh Booch classes/objects Y Y abstract classes Y Y meta-classes Y Y Encapsulation Y Y single inheritance Y Y multiple inheritance Y Y Aggregation Y Y Association Y Y methods/messages Y Y Total 9 9 Real world is concurrent, so object oriented methods often uses concurrent objects in the analysis phase to model it. Objects remain in passive mode, until an operation is invoked by another object to bring them in active mode. If there are more than one thread of control associated with active object, then it is called internally concurrent object. Therefore object oriented methods should support ways to access the shared data in concurrent systems.[5] Table 2. Concurrency Method Passive Active internally concurrent Rumbaugh Y Y Y Booch Y Y Communiication provides information flow and synchronization between objects that are involved in the communication. In Synchronous communication the sender object send a messege to the reciever object and suspend execution until it receives an aknowlegment message from the reciever, whereas in asynchronous communication the sender does not wait for the aknowlegment and continues its execution. Sequential systems uses procedural call whereas concurrent object systems uses remote procedure Call for communication. Table 3. Communication Method Synchronous Asynchronous Procedural Remote procedure Rumbaugh Y Y Y Booch Y Y Y Process 3.2.1. Deliverables that are produced during the Development Process: A number of different types of deliverables are generated during the development process of a system. These include a number of specifications likely requirements, analysis, design, subsystem, and test cases. Particularly, in object-oriented development process, object and classes specifications are very important. Following criteria is used to find out the deliverables that each methodology generates during the development process: 0 shows no deliverable is generated. 1 shows deliverable is generated, but details are not provided. 2 shows deliverable is generated and also well defined. 3 shows deliverable is generated, a definition is provided, and an example is given. 4 shows deliverable is generated, a definition is provided, and an example is given, and a definition for the process is provided. 5 shows deliverable is generated, a definition is supplied, an example is given, a definition for the process is provided, and heuristics are provided. The following table 4 represents the results of this evaluation: Table 4: Development process deliverables Method Rumbaugh Booch Requirement Specification 2 1 Design Specification 2 2 Test Cases 0 0 Object/Class Specification 5 1 Subsystem Specification 0 1 Totals 9 5 3.2.2. Development Contexts A set of constraints occur during the development process which are established by development context. The following criteria are used to evaluate that whether each methodology explicitly discusses the constraints that are established by the development context, or not within the method. A Y in the With Prototyping column shows that prototyping is discussed explicitly in the methodology. A Y in the As Prototyping indicates that prototypes iteratively deliver the system and methodology produces prototypes into production. A Y in the With Reuse shows that the methodology explicitly incorporate the reuse products into the method The For Reuse indicates whether the methodology delivers reusable products for other processes or not. Table 5: Development Context Method Rumbaugh Booch With Prototype Y As Prototype With Reuse Y Y For Reuse Partial Y Aspects of the Development Life-Cycle The whole development life cycle of a methodology gives us a suggestion about the completeness and consistency of the methodology. If a methodology covers all aspects of the development lifecycle during the development process then it ensures the completeness and the consistency of the methodology and it is useful to the organization as a complete and consistent methodology. Therefore, complete life cycle coverage is very important to a life cycle with a limited coverage. Following table 6 values shows these aspects: 0 shows this feature is not covered. 1 shows this feature is covered, but with no details. 2 show this feature is covered with definition. 3 shows this feature is covered, a definition is given with an example (at least one). 4 shows this feature is covered, a definition is given with an example (at least one) and with defined process. 5 shows this feature is covered, a definition is given with an example (at least one) and with defined process, and heuristics are provided. Table 6: Development process life cycle coverage Method Rumbaugh Booch Domain Analysis 0 4 Requirement Analysis 5 2 Enterprise Modeling 0 0 Design 5 5 Implement 3 4 Test 2 0 Total 15 15 In software engineering Extensibility of the system design is a systematic measure of the ability to last or continue. A level of efforts is required to extend a system in range or scope. Table 7: Extensibility Method Completeness Consistency Extensibility Rumbaugh Y Y Y Booch N N N Table 8: Process properties Method Well-defined steps(process) Pure or hybrid Traceable across lifecycle Rumbaugh Y H Y Booch Partial P Partitioning Mechanism When system size increases, then at a particular time, the visibility of certain information about the objects of interest is very crucial and to limit this visibility a partitioning mechanism is required. Each methodology was studied carefully to seek such mechanisms it provides. So the information in the table below was the outcome. Table 9: Partition mechanism Method Partitioning Mechanism Rumbaugh Subsystems Booch Subsystems The Life-Cycle of the Methodologies The development life-cycle of each methodology was carefully reviewed so as to determine that whether the methodology follows a sequential (i-e Waterfall), iterative or recursive strategy because it is the crucial requirement for project planning. Otherwise it will yield unexpected results with high risk and would lead to total failure. The following table 10 shows that which methodology follows what strategy. Table 10: life cycle property Method Recursive Iterative Sequential Rumbaugh Y Booch Y 3.3 Notations 3.3.1. Static Concepts Each methodology was reviewed to determine that how each methodology represents the following concepts: Aggregation: what are the components an object is a composed of. Communication: How the classes or objects communicate with each other(i-e by sending message to one another) Specialization: An object is represented as a generalization, or specialization, of another class or object? Module Interfaces: The physical implementations of objects Qualifications for Reuse: How much each methodology encourages the reuse of different components of development process. These concepts within each methodology indicates that how the models are used. The table 11 below shows the notations for these concepts. Table 11: Static Concepts Method Rumbaugh Booch Aggregation Object Model Class Diagram Specialization Object Model Class Diagram Communication Scenario Class Diagram Module Interfaces Module Qualifications f

Isolation of Protein by Ammonium Sulphate Precipitation

Isolation of Protein by Ammonium Sulphate Precipitation Hypothesis Rubisco is a negatively charged protein that weighs 55,000 kDa and is also very soluble. When we add ammonium sulfate to reach a saturation of 50%, Rubisco can be isolated using ion exchange chromatography and protein electrophoresis. Materials and Methods Isolation of Protein by Ammonium Sulfate Precipitation Approximately 300g of fresh spinach leaves were de-ribbed and dried, then homogenized for 1 minute in 200mL of buffer. From the homogenized solution, approximately 50ml was placed into a beaker, which was stirred on a stir plate while 10.90g of solid ammonium sulfate was slowly added to reach 37% saturation. The solution was stirred for an additional 10 minutes and then centrifuged at 9,000-xg for 15 minutes. The pellet (Pellet I) was resuspended in 4mL of water and transferred into a dialysis bag for dialysis against distilled water. The supernatant was poured into a beaker and stirred on a stir plate while about 3g of ammonium sulfate was slowly added to reach 50% saturation. After about 15 minutes of stirring, the supernatant was centrifuged for 15 minutes at 7,000-xg. Following centrifugation, the pellet (Pellet II) was resuspended in 4mL of water and transferred into a dialysis bag for dialysis. Ion Exchange Column Chromatography The column was equilibrated by running 30mL of Buffer A (10mM Tris pH 8.0, 3mM EDTA) through. Afterwards, a centrifuge was used to pellet down any solid precipitate out of the dialyzed samples. 1mL of each sample (Pellet I and II) was transferred into labeled Eppendorf tubes and frozen for later use in the SDS-PAGE. Pellet I was diluted a 100-fold and about 4mL of diluted Pellet I and undiluted Pellet II were loaded into separate columns and the samples were allowed to flow through. The flow-through was discarded. 10mL of the low salt buffer (Buffer A + 50mM NaCl) was loaded onto the column and fractions of approximately 2mL were collected in separate cuvettes and labeled in order. After blanking the spectrophotometer at 280nm with low salt buffer, the OD readings of each fraction was measured. This process was repeated using the medium salt buffer (Buffer A + 200mM NaCl) and high salt buffer (Buffer A + 500mM NaCl). The spectrophotometer was blanked with each buffer before the readings of its corresponding fractions were obtained. The fractions with the highest OD reading at 280nm was collected in an Eppendorf tube, labeled, and placed on ice. The column was then washed with 10mL resin cleaning buffer which was discarded in a wash beaker. Protein Electrophoresis 30uL of 3X Sample Buffer (bromophenol blue, glycerol, dithiothreitol, and SDS) was added to 60ul of each of the 9 samples (standard, homogenate, Pellet I, Pellet I low, medium and high salt buffers, Pellet II low, medium and high salt buffers). The 9 tubes were heated in a water bath for 4 minutes. Into a prepared buffer chamber, approximately 20uL of each sample were loaded into separate wells using thin-barrel pipette tips. The gel was run at 180 Volts for approximately 50 minutes. The gel was removed from the glass plate sandwich and stained in Staining/Fixing Solution for 30 minutes. The gel was destained overnight in Destaining Solution and then dried ona vacuum gel dryer for one hour. Results Table 1: ODwavelength Readings of Protein Fractions for Pellet I OD Reading (280nm) Tube Low Salt Medium Salt High Salt 1 0.202 -0.077 0.020 2 0.162 0.022 -0.083 3 -0.015 -0.077 -0.059 4 0.246 0.003 -0.068 5 0.002 0.020 0.052 OD readings (280nm) for the fractions were measured using a spectrophotometer after they eluted from the ion exchange column. Table 2: OD Readings of Protein Fractions for Pellet II OD Reading (280nm) Tube Low Salt Medium Salt High Salt 1 HI 0.121 -0.069 2 HI 0.687 -0.059 3 1.442 -0.017 -0.095 4 0.963 0.025 0.200 5 0.229 -0.049 0.320 OD readings (280nm) for the fractions were measured using a spectrophotometer after they eluted from the ion exchange column. Table 3: Known Protein Standards, Relative Molecular Weights and Distance Traveled on Gel Proteins Distance Traveled (mm) Molecular Weight (Daltons) Phosphorylase b 80 97,000 Albumin 130 66,000 Ovalbumin 200 45,000 Carbonic anhydrase 260 30,000 Trypsin Indicator 20,100 Lactalbumin 14,400 The molecular weights of the proteins are known and the distance traveled was gotten by measuring with a ruler from the top of the well to the band of each band. Weight (kDa) Solutions of proteins with known weights were loaded and run in SDS-PAGE and the distance was measured from the top of the well to the bottom of the band. Table 4: title Sample # Sample No. of bands Migration distance (cm) Molecular Weight (kDa) 1 Pellet I Low salt 2 PI Medium salt 3 PI High salt 4 PI 1 2.7 28 5 Pellet II Low salt 1 2.8 26 6 PII Medium salt 7 PII High salt 8 Standard 1 2 3 4 0.8 1.3 2 2.6 97 66 45 30 9 Homogenate 1 2 3 1.8 2.3 2.6 50.3 36 30 The number of bands were tallied, then the molecular weight was collected as well as the migration distance. The migration was found by measuring from the top of the well to the bottom of the band. Four bands showed in the lane where the standard was loaded instead six, because there were six proteins present in the sample this does not make sense to me. Three bands give sizes appeared in the homogenate and one band in Pellet I and Pellet II low salt. Discussion Rubisco weighs 55,000 kDa according to literature and gel bands that correlate with it that size did not appear in either of the samples. It was predicted Rubisco is very negatively charged and very soluble, therefore it should elute the column at a high salt concentration because a large concentration of salt should be needed to disrupt the bonds created between the negatively charged ion of Rubisco and the positively charged resin, but the high salt buffer fractions had some of the lowest OD readings which is conflicting with our prediction. Instead, the OD readings were highest with the low salt buffer concentration. This could mean that Rubisco is not as negatively charged and soluble as we predicted. I cannot clearly conclude if Rubisco was isolated or not because the gel ripped and a big chunk of it was missing due to mishandling. Also, Rubisco might have been lost due to contamination because they were no bands that correlated with its molecular weight. Good! The quality of the experiment could be improved by some additional methods to identify Rubisco since it fixes carbon dioxide. Therefore they could be a test to show that the protein that was isolated can actually fix carbon dioxide.

Comparing the Themes of Vincenzio Bellini’s Norma and Euripedes Medea

Comparing the Themes of Vincenzio Bellini’s Norma and Euripedes' Medea Vincenzio Bellini’s opera Norma is considered by many to be a reworking of Euripedes' classic Greek tragedy Medea. Both plots have many identical elements of Greek tragedy such as a chorus, unity of location, and a human decision and action culminating in tragedy. Richard Wagner greatly admired Greek tragedies, believing them to be â€Å"The highest point ever reached in human creative achievement†¦Ã¢â‚¬  (Wagner 1). In his essay Theories of Art, Wagner gives five reasons for this â€Å"artistic perfection:† 1. It represented a successful combination of the arts-- poetry, drama, costumes, mime, music, dance and song-- and as such had greater scope and expressive powers than any of the arts alone. 2. It took its subject matter from myth, which illuminates the human experience in universal terms. (â€Å"The myth is true for all times.† (Wagner 2)) 3. Both the content and the occasion of performance had religious significance. 4. It was a religion of humanism and a celebration of life, even in death. 5. The entire community took part. Medea also deals heavily with the themes of female jealousy, its capabilities, and infanticide, as does Norma. Norma exhibits not only the embodiment of these themes, but also exhibits Wagner’s theories of effectiveness of Greek tragedy, therefore qualifying Bellini’s opera to be as effective in portraying the classic ideals of Greek tragedy as its counterpart, Medea. Wagner believed that as time went on, Greek art slowly disintegrated, each individual art going a separate way, developing alone—instrumentals without words, poetry without music, drama without either, etc. He believed it further disintegrated with the introduction of Christiani... ...s; Medea; Trans. Rex Warner. The Harcourt Brace Anthology of Drama: Third Edition. Orlando: Harcourt, 2000. Georgousi, Fotini; Tragic Women: Plotting and Transgressing; Minnesota University Press; 2001. McIver, Barbara Basore, B.A., M.A.; Good Girls, Bad Girls and Heroines; Models from Myth; University of Akansas Press; 1968. Plunka, Gene A. Ed. Antonin Artaud and the Modern Theater; New Jersey: Associated UP, 1994. Romani, Felice; Norma (libretto) trans. Olcese, Stefano, 2000. Romani, Frederico; Alexandre Soumet and his Three Muses; Minnesota Opera Pubs. 2003. Schumacher, Claude and Brian Singleton. Eds. Artaud on Theatre; London: Methuen, 1989. Sferro, Nuccio; Norma Libretto Notes; Stanford University Press, 2000. Wagner, Richard; Bellini: A Word in Season; trans. William Ashton Ellis; Wagner’s Prose Works Vol. 8 pp. 67-69, 1899.

acid rain :: Free Essay Writer

Impacts of Acid Rain Air Pollution Creates Acid Rain Scientists have discovered that air pollution from the burning of fossil fuels is the major cause of acid rain. Acidic deposition, or acid rain as it is commonly known, occurs when emissions of sulfur dioxide (SO2) and oxides of nitrogen (NOx) react in the atmosphere with water, oxygen, and oxidants to form various acidic compounds. This mixture forms a mild solution of sulfuric acid and nitric acid. Sunlight increases the rate of most of these reactions. These compounds then fall to the earth in either wet form (such as rain, snow, and fog or dry form (such as gas and particles). About half of the acidity in the atmosphere falls back to earth through dry deposition as gases and dry particles. The wind blows these acidic particles and gases onto buildings, cars, homes, and trees. In some instances, these gases and particles can eat away the things on which they settle. Dry deposited gases and particles are sometimes washed from trees and other surfaces by rainstorms. When that happen s, the runoff water adds those acids to the acid rain, making the combination more acidic than the falling rain alone. The combination of acid rain plus dry deposited acid is called acid deposition. Prevailing winds transport the compounds, sometimes hundreds of miles, across state and national borders. Mobile sources (transportation) also contribute significantly to NOx emissions. Overall, over 20 million tons of SO2 and NOx are emitted into the atmosphere each year. Acid rain causes acidification of lakes and streams and contributes to damage of trees at high elevations (for example, red spruce trees above 2,000 feet in elevation). In addition, acid rain accelerates the decay of building materials and paints, including irreplaceable buildings, statues, and sculptures that are part of our nation's cultural heritage. Prior to falling to the earth, SO2 and NOx gases and their particulate matter derivatives, sulfates and nitrates, contribute to visibility degradation and impact public health. Acid rain primarily affects sensitive bodies of water, that is, those that rest atop soil with a limited ability to neutralize acidic compounds (called "buffering capacity"). Many lakes and streams examined in a National Surface Water Survey (NSWS) suffer from chronic acidity, a condition in which water has a constant low pH level. In some sensitive lakes and streams, acidification has completely eradicated fish species, such as the brook trout, leaving these bodies of water barren.

Define the Key Terms Essay

Application: Generally, a function on any kind of computer or electronic device that is useful to the user, which can give the user a reason to want to own and use the device. More specifically, software that performs some useful function for a user. Computer network: A combination of many components that work together so that many different devices can communicate. Computer networking: The gerund form of the term computer network. Email: Electronic mail. An application in which the user can type text and attach other files to create the electronic equivalent of a postal letter, and send the email to another person using his or her email address. Enterprise network: A network owned and operated by a company, with that company being somewhat larger than typical, generally (but not exactly) with more than 1000 employees. HTTP: Hypertext Transfer Protocol, The protocol  used by web browsers and web servers to define the format of URLs (web addresses) and the messages used to exchange web objects. Internet/the Internet: The global network formed by interconnecting most of the networks on the planet, with each home and company network connecting to an Internet service provider (ISP), which in turn connects to other ISPs. Link: A generic term for any network cable or wireless communications path between two devices over which bits can be transmitted. Node: A generic term for any networking device that sits on the end of links, for the purpose of both connecting links to create physical paths and to make decisions about how to forward data through the network. Protocol: A set of rules that different devices and/or software must follow so that the network works correctly. Video frame: A grid of pixel locations of a chosen width by height that contains the lights/colors to be shown in a video at a single point in time. Voice call: A more modern term for a telephone call that does not use the word telephone, instead emphasizing the fact that the traffic that flows between the endpoints is voice. Web address: Text that identifies details about one object in a network so that a client can request that object from a server. An informal term for URL. Web browser: Literally, software controlled directly by a user that requests web pages from a web server, and after receiving a page, displays the web page in a window. More generally, this term refers to both the software and the hardware on which it executes. Web page: In a web browser, all the text, images, video, and sound that fill the window of the browser when the user opens a link to some web address. Web server: Literally, software that stores web pages and web objects, listens for requests for those pages, and sends the contents of those pages/objects to clients. More generally, this term refers to both the software and the hardware on which it executes.

Financial Crisis and Brazil Essay

The economic crisis that has swept the world since 2008 has wrought havoc in national economies all over the world. As a group, one of the more particularly hard-hit groups of nations has been the Latin American countries of Central and South America. One notable exception to this trend appeared to be the nation of Brazil. The gloomy projections appeared not to apply to Brazil. According to Mauricio Cardenas of the Brooking institute: This doom and gloom has not infected Brazil, however, where President Luiz Inacio Lula da Silva is showing unprecedented self-assurance. Speaking in Madrid, Lula said somewhat rhetorically that â€Å"this idea that markets can do everything is over,† and more fundamentally â€Å"The times in which emerging countries depended on the IMF are over. † This is not Hugo Chavez speaking, but the president of Latin America’s largest economy, who enjoys 80 percent popularity in his country. (Cardenas, 2008) Although Brazil weathered the early months of the financial crisis better than its Latin American neighbors, the longer the crisis has continued, the more the Brazilian economy has weakened. One of the factors that prevented an immediate collapse of the Brazilian Economy in the wake of the 2008 Crisis was the relative lack of foreign banks in the country. (Cardenas, 2008) Unlike many Latin American nations that have a high percentage of foreign banks (i. e. Mexico: 80% foreign banks), Brazil has only 30% foreign banks. (Cardenas, 2008) In the short term, this allowed Brazil to assume that a contraction in foreign lending would not have as deep an impact on their economy than that of other nations. Brazilian banks, in times of previous economic prosperity, had built reserves, rather than engaging in profligate loaning, leading to the hopes that these reserves were sufficient against the day that foreign banks severely restricted credit. (Cardenas, 2008) By September of 2008, this theory seemed to erode in the face of certain economic indicators. The Bovespa index, a market indicator similar to the Dow Jones industrial Average, lost half of its value from May to September of 2008. (Cardenas, 2008) 10% of that drop occurred in the second half of September. More strikingly, the value of Brazil’s currency, the Real, fell 32% against other world currencies. (Cardenas, 2008) These factors show that Brazil may still be prone to suffer in the economic crisis. Other analysts, such as John Williamson of the Peterson Institution of international Economics, have been less sanguine about the prospects of Brazil’s economy. Wiliamson stated: Moreover, the markets decided that while many of the emerging economies might no longer have any need for an inflow of loans, many (like Brazil) are still significant net debtors to the rest of the world and therefore still vulnerable to a sudden withdrawal of foreign credit. Compounding this is the fact that one may have a balanced overall position and still be vulnerable because debts are concentrated at short maturities. Hence one read, for example, of the Bovespa index falling by over 10 percent in a day (it has cumulatively halved in value since the peak in May). Likewise, the real has fallen by a cumulative 32 percent in the past month. The markets clearly do not believe that Brazil has been made invulnerable†¦ (Williamson, 2008) The world market contraction has had a significant effect on Brazil’s foreign trade. (Williamson, 2008) The export economy has relied upon raw materials for 50% of exports, and the prices of these materials have dropped dramatically in the face of world-wide declines in demand. (Williamson, 2008) The other half of Brazil’s exports, differentiated manufactured goods have also decreased in the face of reduced demand. Ironically, the weakness of the real against foreign currencies has softened the negative effect of these factors. (Williamson, 2008) The soft real will inspire increased purchase of manufactured goods from Brazil. This will soften, but not eliminate, the negative effects of low demand. The decrease in foreign capital that these commodity price decreases have reflected, will rapidly eat through Brazil’s trade surplus, and put strain on lending institutions in Brazil. (Williamson, 2008) The future of Brazil’s economy has been reported with varying degrees of optimism. The GDP of Brazil is projected to contract anywhere from 1. 5 to 20% in 2009 after growing 5% in 2008. (Williamson, 2008) An increase in the shift of agricultural exports to China has also contributed to the overall positive projections of the Brazilian economy. (Xinhua, 2009) The increase from March of 2008 (8. 5%) to March of 2009 (12. 5%) amounts of agricultural exports to China reflect this phenomenon. (Xinhua, 2009) The president of Brazil claims that the crisis has passed, and that Brazil has weathered the worst part of the economic crisis of 2008. (Xinhua, 2009) The longevity of the world-wide recession will determine if this is in fact a true prediction. (Xinhua, 2009) Brazil weathered the economic crisis of 2008 comparatively well, but suffered great financial repercussions late in the year. The economy seems to be in a stage of recovery, but its continued well being will rely on the recovery of other nations that control lending power and demand for Brazil’s exports. Work Cited Cardenas, M. (2008) â€Å"Global Financial Crisis: Is Brazil a Bystander? † Retrieved June 4th, 2009 from Brookings Institution website: http://www. brookings. edu/opinions/2008/1015_financial_crisis_cardenas. aspx Williamson, J. (2008) â€Å"The Impact of the Global Financial Crisis on Brazil† Retrieved June 4th, 2009 from Peterson Institution of international Economics website: http://www. iie. com/publications/papers/williamson1008. pdf Xinhua (2009) â€Å"Brazil’s agricultural exports to China up 52. 5 percent in March† Retrieved June 4th 2009 from China’s people’s Daily website: http://english. people. com. cn/90001/90778/90857/90861/6634356. html