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,*,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,1,Unit 7 How to Write the Materials and Methods,2,1. Purpose,2. Content and Structure,3. Sample Analysis,4. Grammar and Writing skills,5. Summary,6. Exercises,3,The title of this section varies in different disciplines and in different journals.,Materials and Methods,Procedure,Experiments,Experimental,Simulation,Methodology,Model,4,1. Purpose of the section,1) to describe the experimental design and provide sufficient details so that other researchers can repeat the experiments,2) to provide information that will let readers judge the appropriateness of the experimental methods (and thus the probable validity of the findings),5,2. Content and Structure,Materials,Include the exact technical specifications , quantities, and source or method of preparation.,6,Methods,If your methods have not been reported previously, you must provide all of the necessary detail.,If, however, the methods have been previously described in a standard journal, provide only that literature reference.,If you modified a previously published method, provide the literature reference and give a detailed description of your modifications.,7,Organization,Arrange experimental details in chronological order or by subsections,Subheading,8,3. Sample Analysis,Read the sample Methodology and write a shorting description of what the writer is doing in each sentence.,9,The current investigation involved sampling and analyzing six sites to measure changes in groundwater chemistry. The sites were selected from the London Basin area, which is located in the south-east of England and has been frequently used to interpret groundwater evolution.,1,2,3,A total of 18 samples was collected and then analyzed for the isotopes mentioned earlier. Samples 1-9 were collected in thoroughly-rinsed 25 ml brown glass bottles which were filled to the top and then sealed tightly to prevent contamination. The filled bottles were shipped directly to two separate laboratories at Reading University, where they were analyzed using standard methods suitably miniaturized to handle small quantities of water.,4,Samples 10-18 were prepared in our laboratory using a revised version of the precipitation method established by the ISF Institute in Germany.,5,This method obtains a precipitate through the addition of BaCl,2,.2H,2,O; the resulting precipitate can be washed and stored easily.,The samples were subsequently shipped to ISF for analysis by accelerator mass spectrometry (AMS). All tubing used was stainless, and although two samples were at risk of CFC contamination as a result of brief contact with plastic, variation among samples was negligible.,10,The current investigation,involved,sampling and analyzing six sites to measure changes in groundwater chemistry. The sites,were selected,from the London Basin area, which,is,located in the south-east of England and has been,frequently,used to interpret groundwater evolution.,1,2,3,In sentence 1 the writer offers a general overview of the entire subsection, including the purpose of the investigation.,In sentence 2 the writer provides background information and,justifies,the choice of location by referring to previous research.,11,A total of 18 samples was collected and then analyzed for the isotopes mentioned earlier. Samples 1-9 were collected in,thoroughly-rinsed,25 ml brown glass bottles which were filled to the top and then sealed,tightly,to prevent contamination. The filled bottles were shipped,directly,to two,separate,laboratories at Reading University, where they were analyzed using,standard,methods,suitably,miniaturized to handle,small,quantities of water.,4,In sentence 3 the writer provides an overview of the procedure/method itself.,In sentence 4 the writer provides details about what was done and used, and also shows that care was taken.,In sentence 5 the writer continues to describe what was done in detail, using language which communicates that care was taken.,12,Samples 10-18 were prepared in our laboratory using a,revised,version of the precipitation method established by the ISF Institute in Germany.,5,This method obtains a precipitate through the addition of BaCl,2,.2H,2,O; the resulting precipitate can be washed and stored easily.,In sentence 6 the writer describes what was done by,referring to existing methods in the literature.,In sentence 7 the writer provides more detailed information about the method and shows it to have been a good choice.,13,The samples were,subsequently,shipped to ISF for analysis by accelerator mass spectrometry (AMS). All tubing used was stainless, and although two samples were at risk of CFC contamination as a result of brief contact with plastic, variation among samples was,negligible.,In sentence 8 the writer provides more details of the method.,In sentence 9 the writer mentions a possible difficulty in the methodology.,14,Why do I need to justify or give reasons for what I did Isnt it obvious,If you fail to provide justification for what you did, the reader my not accept the validity of your choice. They may wonder why you did things in a particular way, or why you used a particular procedure.,If you dont explain why you did things then readers cannot be expected to accept your methodology, and this will eventually affect the way they evaluate your whole paper.,15,Many writers believe that this section is just an impersonal description of what was done or used; in fact there is a strong,persuasive,and,communicative,element.,In the description of your materials and methods, you need to communicate not only,This is exactly what I did/used,but also,I had good reasons for those decisions.,16,Evaluate the Materials and Methods section of your target papers.,1. Identify how the authors start this section.,2. Write the topic of each paragraph.,3. Identifyif possiblethe topic sentences.,4. Identifyif possiblean example of each technique of continuity:,a. repeated key term,b. transition word and transition phrase or clause,c. parallel form,5. Are the paragraphs of this section organized well,17,4. Grammar and Writing Skills,4.1 Passives and Tense Pairs,4.2 Use of a and the,4.3 Writing Style,4.4 Use of Parentheses,18,4.1 Passives and Tense Pairs,We/I collected the samples.,active,The samples were collected.,passive,19,(a) A flexible section is inserted in the pipe.,present simple passive,(b) A flexible section was inserted in the pipe.,past simple passive,When you write about what you did and what you used, you need to be able to distinguish between standard procedures, i.e. what is normally done or how a piece of equipment is normally constructed, and what you did yourself.,20,In the examples above, (a) uses the Present Simple tense to describe what is normally done or to describe a standard piece of equipment used in the research and (b) uses the Past Simple tense to describe what you did yourself.,21,Samples for gas analysis were collected using the method described by Brown (1999), which uses a pneumatic air sampling pump.,22,Common problems with writing passive sentences,Example 1,Wheat and barley, collected from the Virginia field site, as well as sorghum and millet, collected at Loxton, were used. (,),Four cereals were used: wheat and barley, collected from the Virginia field site; and sorghum and millet, collected at Loxton. (),This improved example demonstrates a very effective sentence structure for writing lists in English.,23,Example 2,The assays,were performed,for 10 min at room temperature.,We,then,added,10 ml of 95% ethanol. (),The assays,were performed,for 10 min at room temperature. Then 10 ml of 95% ethanol,were added.,24,4.2,Use of a and the,How do you make a choice between a/an and the,25,Singular countable nouns need a determiner.,A determiner is a word like,the,a,my,one,some,.,Its a difficult rule to operate successfully because two problems need to be solved before you can use it.,Firstly, its hard to know exactly which nouns are countable.,26,There have been three,deaths,this year from pneumonia.,Many,industries,rely on fossil fuels.,Some,steels,are used in the manufacture of medical instruments.,27,The way you use a noun determines whether it is used in its countable or uncountable form.,When you use a noun like industry, stop and think do you mean industry in general (uncountable) or a particular industry (countable),28,Now look at the second problem: how do you decide whether to use a or the,There is a book on the shelf above my desk; can you bring it here,I had a cheese sandwich and an apple for lunch. The sandwich was fine but the apple had a worm in it.,29,When both you and your readers know who or what you are referring to, you can use the.,This is true even if the thing or person has not been mentioned before, for example, in the following sentences:,Did she get the job,Ill meet you in the library later.,30,Sometimes the choice of,a,or,the,changes the meaning of the sentence completely:,1) This effect may hide,a,connection between the two.,2) This effect may hide,the,connection between the two,.,31,1) There may possibly be a connection between the two but if there is, we cannot see it.,2) There is definitely a connection between the two but we may not be able to see it because of the effect.,32,The nodes should be attached to two adjacent receptor sites.,The nodes should be attached to,the,two adjacent receptor sites.,33,The electroencephalograph is a machine for measuring brain waves.,An electroencephalograph is a machine for measuring brain waves.,Electroencephalographs are machines for measuring brain waves.,34,4.3 Writing Style,The sample was then placed on a 300600 mm stainless steel sheet and heated in a Panasonic E458500 w standard fan-assisted oven for 90 minutes at 350.,Now put the chicken in a hot oven for about an hour and a half.,35,4.4 Use of Parentheses,To provide enough details while maintaining good flow in your writing, parentheses are commonly used in the Materials and Methods section. Often these technical specifications include manufacturers names, lot numbers, names of machinery, and additional explanations and specifications.,Example,To assess trends over time, we calculated relative abundances of species, averaging monthly capture data over 6-month periods (January-June and July-December).,36,5. Summary,1). Provide sufficient details and references to enable a trained scientist to evaluate or repeat your work.,2). Signal and link the different topics.,3). Explain the purpose for any procedure whose function is not clear.,4). In the Materials and Methods section, passive voice is often preferred.,37,6. Exercises,For each pair of sentences provided, select the better version and explain why you chose it.,1). a. Seedlings were grown in a continuous light before being collected.,b. Seedlings were grown in a continuous light at 15 for 21 days before being collected.,38,2). a. Here we provide a description of how subjects were chosen for our study. We selected only healthy males between 60 and 80 years.,b. For our study, we selected only healthy males between 60 and 80 years.,39,3). a. Study subjects were presented with a list of potentially traumatic events, and we asked them to use three responses categories (yes, no, unsure) to indicate if they had ever experienced them.,b. Study subjects were presented with a list of potentially traumatic events, and were asked to use three responses categories (yes, no, unsure) to indicate if they had ever experienced them.,40,4). a. The Stress Index Short Form (SI/SF), which is a 36-item questionnaire, was used to assess stress after natural disasters (26).,b. The Stress Index Short Form (SI/SF), which was a 36-item questionnaire, was used to assess stress after natural disasters (26).,
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