Even the protein crystallographic part of the project may become a source of problems. In this context, it is not surprising that methods dealing with the prediction of protein structure have gained much interest. Among these methods, the method of homology modeling usually provides the most reliable result. The use of this method is based on the observation that two proteins belonging to the same family an sharing similar amino acid sequences , will have similar three-dimensional structures.
In reality, the degree of conservation of protein three-dimensional structure within a family is much higher than conservation of the sequence. Quality criteria, model quality; After finding a template it is an absolute requirement to make a multiple sequence alignment , which should include your sequence of course, the sequence of the template and some other sequences of proteins of the same family. This will give an overview of the general features of the protein family, the degree of conservation, the presence and location of consensus sequence motifs, etc.
It would also be very desirable to make secondary structure prediction, discussed in the tutorial on sequence alignment. Most importantly, the positions of insertions and deletions should be correct outside regions of secondary structure , likewise the conserved residues, for example active site residues, should be aligned against each other. He exploits a natural experiment to assess the difference institutional reform makes to institutional performance over his 20 year period of study. Upon recognising disparities in regional findings, he then assesses the reasons for cross-sectional and cross-temporal variation in institutional performance, moving to a more in-depth focus on 6 regions.
Although the case study discipline is beginning to decline in the modern academic sphere, the strengths of this kind of research design are still evident. Landman highlights some of the main strengths of case studies such as these, writing:. In short, the case study method allows an intensive depth study of a unit with limited resources.
As Landman statement suggests, they are extremely flexible and can serve a multitude of purposes. Making Democracy Work is also a prime example of another key strength of case studies — utilising process-tracing to uncover evidence of causal mechanisms or to explain outcomes.
Comparative Design of Structures - Concepts and Methodologies | Lin Shaopei | Springer
Other comparative methods, such as large-N, are far less conducive to this type of process tracing and unearthing of causal mechanisms. They are often able to say what happened, but not necessarily how it happened. The detail in which these mechanisms are explained is also far less extensive. Despite the strengths highlighted above, there are also some considerable limitations to the case study method that have been recorded extensively in the literature of the social sciences. Furthermore, case studies are usually better at description than establishing causation.
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The case study method is also considered intensive rather than extensive, as it tends to offer a great deal of in-depth analysis of a single unit at the expense of breadth analysis. With Putnam, for example, the study has a sole focus on Italy and Italian institutions and social capital over years. Finally, where larger-N studies often confirmatory in their nature, seeking to either confirm or reject hypotheses, case studies tend to be more exploratory, attempting to gain new insights into a topic or unit from which new hypotheses might be later developed.
Many have argued that his case selection is based upon MSSD.
Comparative Research Methods
As with the case study method, there are numerous advantages to using small-N research designs — often called the comparative method — in comparative politics. One of the most significant strengths of using the comparative method comes from the intentional selection of cases as previously mentioned.
Not only can it be a substitute for the experimental control evident in large-N analysis, the intentional selection of cases that share similar characteristics means that hypothesis testing is made easier. The result of this is greater confidence that chosen concepts are being accurately measured. These intensive analyses can be more fruitful than superficial statistical analysis of many cases that can be extremely time-consuming and difficult to execute successfully.
The collection of large data sets has also proved extremely difficult. It could be argued that the weaknesses of the comparative method, or small-N research designs, out-weigh its strengths. Lijphart, ; Goggin, Problems often arise when comparing few countries when there are more factors identified explaining the observed outcome than there are countries observed. This eventually becomes problematic when too many cases are added and the research passes from the small-N comparative method in to the large-N statistical analysis method.
Qualitative Research Methods & Methodology
Using the small-N design that Linz has can therefore be extremely problematic. The design is also cross-sectional, as data is collected from 54 elections around the world c. Multivariate regression is used to assess the different impact each of the independent variables has on the dependant variable. A particularly key advantage of using the large-N statistical method is the fact that statistical controls can be used to rule out rival explanations for an observed outcome and to control for potentially confounding factors.
Large-N analyses also allow for an extensive coverage of countries over both space and time. Refresh your browser page to run scripts and reload content. Click the Internet Zone. If you do not have to customize your Internet security settings, click Default Level. Then go to step 5.
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