Teacher: In this task, you are given a paragraph (from a research paper) and your task is to classify each sentence of the paragraph (assume n sentence) into the following categories: Background, Purpose, Method, Finding/Contribution, or Other. Return the output in this format: 1 - category of sentence 1, 2 - category of sentence 2, ..., n - category of sentence n; where each number indicates the order of the sentence. The categories can be identified using the following questions: 
 Background: - Why is this problem important? - What relevant works have been done before? - What did the previous works miss? - What are the high-level research questions? - How might this help other researchers?
 Purpose: - What specific things do the researchers want to do? - What specific knowledge do the researchers want to know? - What specific hypothesis do the researchers want to test?
 Method: - How did the researchers do it or find it out? - What are the procedures and steps of this research?
 Finding/Contribution: - What did the researchers find out? Did the proposed methods work? - Did things behave as the researchers expected?
Other: put every text fragment that does not fit into any of the categories above here. Put a sentence here if its not in English, is not part of the article, contains numbers and dates, is a caption of a figure or a table, is a formatting error, or you are not sure about it.
Teacher: Now, understand the problem? If you are still confused, see the following example:
In many infectious diseases caused by either viruses or bacteria, pathogen glycoproteins play important roles during the infection cycle, ranging from entry to successful intracellular replication and host immune evasion. Dengue is no exception. Dengue virus glycoproteins, envelope protein (E) and non-structural protein 1 (NS1) are two popular sub-unit vaccine candidates. E protein on the virion surface is the major target of neutralizing antibodies. NS1 which is secreted during DENV infection has been shown to induce a variety of host responses through its binding to several host factors. However, despite their critical role in disease and protection, the glycosylated variants of these two proteins and their biological importance have remained understudied. In this review, we seek to provide a comprehensive summary of the current knowledge on protein glycosylation in DENV, and its role in virus biogenesis, host cell receptor interaction and disease pathogenesis.
Solution: 1 - background, 2 - background, 3 - background, 4 - background, 5 - background, 6 - background, 7 - background, 8 - background, 9 - background, 10 - background, 11 - purpose, 12 - purpose, 13 - purpose
Reason: The paragraph contains 13 sentences. The first 10 sentences provide background information about how some infectious diseases are caused by bacteria and viruses. The last 3 sentences talk about the purpose of the study.

Now, solve this instance: Objectives: 1) To compare the 2-year completed suicide and reattempt rates in a preintervention group of Hong Kong Chinese suicide attempters (aged 65 years and older) who received standard care and a postintervention group enrolled in a regional elderly suicide prevention program (ESPP) that adopts a two-tiered multifaceted care management model and 2) to examine the trend of suicide rates in older adults aged 65 years and older in the pre-and postintervention periods. Design: The first part is an observational cohort study with baseline, follow-up, and outcome data being identified from a clinical electronic registry. The second part examines changes in suicide rates from official mortality statistics. Setting: A government-funded suicide intervention program serving catchment population (852,796 people aged 65 years and older) in Hong Kong, China. Participants: Suicide attempters (aged 65 years and older) presenting to old-age psychiatric service in the pre-and postintervention phases. Measurements: 1) Two-year rates of completed suicide and suicide reattempt and 2) changes in population suicide rates in the pre-and postintervention periods. Results: The 2-year completed suicide rate was 7.58% in the preintervention group (N = 66) and 1.99% in the ESPP group (N = 351) χ 2 = 6.192; p value: 0.028; df = 1). Reattempt rates were not different. At a population level, suicide rate dropped significantly only in women aged 85 years and older, relative to the preintervention period. Conclusions: The ESPP was associated with a reduced rate of completed suicide in old-age suicide attempters and might have contributed to a fall of suicide rate in women aged 85 years and older. (Am J Geriatr Psychiatry 2011; 19:1-12) 
Student:
1 - purpose, 2 - method, 3 - method, 4 - method, 5 - method, 6 - method, 7 - method, 8 - finding, 9 - finding, 10 - finding, 11 - finding, 12 - finding, 13 - other