Thematic Structure and Thematic Progression in Research Articles Published in Scopus-Indexed International Journals

____________________ Abstract _________________________________________________________________ Publishing in highly-indexed journals is greatly competitive, thus writing a qualified and eligible text becomes more challenging for a second/foreign language writer of English. A good text should be written logically and organized effectively according to the role of good academic writing. Thematic structure and thematic progression contribute to the development of a well-structured meaningful text. This study examines the use of thematic structure and thematic progression in research articles published in Q1 and Q2 Scopus-indexed international journals as well as their relationship to achieve the texts’ coherence. This is a descriptive qualitative study within the framework of Systemic Functional Linguistics (SFL) that employs discourse analysis. 3426 clauses gathered from ten research articles were analyzed by using Halliday and Matthiessen’s (2014) taxonomy of thematic structure and Eggins’s (2004) theory of thematic progression. This study highlights three major findings. Firstly, in terms of thematic structure, the textual theme is massively used followed by the topical and interpersonal theme. The predominance of the textual theme implies the authors’ ability in developing the logical


INTRODUCTION
Publishing in a highly-indexed or reputable journal especially a Scopus-indexed journal is highly competitive, especially for a second/foreign language (ESL/EFL) writer of English. It is due to the quality of the foreign language used in the paper being scrutinized. The submitted paper should match a good standard in which it should be qualified, eligible, and expressive enough. Moreover, Scopus -a highlyindexing and the largest database in various kinds of research discipline -challenges Indonesian scholars as EFL writers to struggle and compete with other writers around the world to publish their writing in the journals it indexes.
Meanwhile, writing academic papers including research articles are considered challenging and problematic by especially most EFL learners or writers. It is because creating a good piece of writing requires not only the high frequency of the foreign linguistic rules but also excellent cognitive skills for organizing and expressing ideas (Asif et al., 2020). In other words, they not only need to generate and organize ideas using an appropriate choice of vocabulary, sentence, and paragraph organization but also turn the ideas into a readable, cohesive, and coherent text. As suggested by (Thornbury, 2005) that a good text has elements that hang together and need to make sense to the readers.
Dealing with cohesive and coherent texts, thematic structure and thematic progression play a pivotal role to generate the cohesiveness and coherence of writing. Both are the main aspects of how speakers or writers construct their message smoothly into the unfolding language event (Thompson, 2014) and how the ways of thinking and expression flow through the aspect of theme and rheme (Al Bakaa, 2014). Regarding this, Halliday and Matthiessen (2014) state that thematic structure is the basic form of the organization of a clause as a message realized through the Theme-Rheme structure. Theme is the first element of a clause and the rest is called rheme. Besides, thematic progression helps the development of between clauses and the flow of information in a text (Eggins, 2004).
In terms of thematic structure, Halliday and Matthiessen (2014) lay down three types of thematic structure, namely topical or ideational, interpersonal and textual theme. First, the topical theme is the first element of a clause that may be nominal group, nominal group complexes, adverbial groups, prepositional phrases or embedded clauses. Second, the interpersonal theme is the theme that occurs before the topical theme. It indicates the relationship between participants in the texts, or the position or the point of view that is being taken in the clause. Third, the textual theme signals the coherence of the text and helps structure the text by developing links to other clauses realized through continuatives, structural conjunctions, and conjunctive adjuncts.
In terms of thematic progression, Eggins (2004) proposes three types of thematic progression patterns, called theme reiteration, the zig-zag pattern, and the multiple rheme pattern. First, the theme reiteration pattern allows the speaker or writer to keep a text-focused through reiterating an element. Second, the zig-zag pattern helps a text make sense by building on newly introduces information and contributes to the text a sense of cumulative development which does not happen in theme reiteration. Third, the multiple rheme pattern helps the readers to recognize the focus and follow the flow of the idea in the text easily.
Besides, the analysis of the thematic structure and thematic progression is done to see the logical relations between clauses in the texts. The logical relationship has some relations that make connections between two or more clauses. It shows how sentences are connected to convey the purpose of a text to be understood by readers. The logical relations constructed by the thematic progression are classified into additive, adversative, causal, and temporal by Thornbury (2005). In addition, thematic progression theory is mostly used to analyze texts in the academic field. The purpose of thematic progression is to create a well-structured text indicated through the unity and connectedness between sentences.
Some studies have also been carried out to evaluate the coherence of texts through the use of thematic structure and thematic progression (e.g. Arabi & Ali, 2015;Suwandi, 2016;Fitriati & Yonata, 2017;Priangan et al., 2020). Suwandi (2016) examined the level (micro and macro) of coherence as well as cohesion in students' writing abstracts and found that the texts have not satisfactorily achieved coherence through some devices including as the logical relationship cannot be identified. Moreover, Arabi and Ali's study (2015) reported that one of the coherence errors occurs in dealing with the information structure (theme-rheme).
Some linguistic scholars also have great intentions in implementing and examining the use of both thematic structure and thematic progression in the teaching field, especially in teaching writing (e.g. Fang & Li, 2015;Dalimunthe, 2018). The findings show that implementing thematic structure and thematic progression analysis promote students' writing ability as well as encourage the success of the teaching of writing. Meanwhile, Arunsirot's (2013) study reveal that EFL students have at least five problems in using the thematic structure and thematic progression pattern including the problem of empty theme, the problem of the brand new theme, the overuse of constant progression, the problems of empty rheme, and the confusion of textual theme selection.
Triggered by those previous studies, it is interesting to investigate how research articles published in reputable or highly-indexed journals (Scopus-indexed) are textually presented in which the articles may be the role models of wellorganized meaningful texts. Regarding this, a concern comes up through this study to examine how thematic structure and thematic progression are used in research articles published in Scopusindexed international journals and how the relationship between these elements results in the texts' coherence. Thus, the research questions are formulated as follows: How is the use of thematic structure in research articles published in Scopus-indexed international journals?
How is the use of thematic progression in research articles published in Scopus-indexed international journals?
How is the relationship between thematic structure and thematic progression in achieving the texts' coherence?

METHODS
This study is a descriptive qualitative study within the framework of Systemic Functional Linguistics (SFL) that employed discourse analysis. The descriptive qualitative approach was used as it provides intensive description and analysis of a single entity. A descriptivequalitative design is ideal as it is fundamentally interpretive (Creswell, 2012). Since the primary purpose of this study is to analyze, describe, categorize, and interpret the data to examine how thematic structure and thematic progression were used and how their relationship achieve the texts' coherence, a descriptive qualitative study was considered appropriate. In addition, discourse analysis itself is defined as an attempt to study the organization of language above the sentence or clause, and therefore to study larger linguistic units, such as conversational exchanges or written text (Widdowson, 2007).
The data in this study involved 3426 clauses gathered from all sections of ten research articles published in Scopus-indexed international journals in the Asiatic Region. The journals are those of the open-access journals in Quartile 1 (Q1) and Quartile 2 (Q2) ranked by Schimago Journal Ranking (SJR). The articles which were purposively selected are in the area of Asiatic Region specifically in the subject area of Art and Humanities, in the category of Language and Linguistics, especially in English teaching and learning. The unit of analysis is the clauses of the research articles, including the clausecomplexes. The data were collected and analyzed by applying three observation sheets as the data instruments.
In analyzing the data on the use of thematic structure and thematic progression, the framework of thematic structure proposed by Halliday and Matthiessen's (2014) and the thematic progression taxonomy by Eggins' (2004) were employed. Moreover, the analysis of the relationship between those two components in achieving the texts' coherence referred to the logical relations proposed by Thornbury (2005).
The procedure of analyzing the data followed several steps. First, close-reading the texts. Second, classifying the clauses and arranging them in the instrument datasheet.
Third, identifying and classifying the thematic structure based on the taxonomy proposed by Halliday and Matthiessen (2014). Fourth, identifying and classifying the thematic progression patterns based on Eggins's (2004) theory. Fifth, tabulating the thematic structure and thematic progression patterns. Sixth, interpreting the data by making a personal assessment related to the data analysis. Seventh, validating the research results through investigator triangulation. Eight, correcting the results of the analysis by adding some feedback from the triangulator to strengthen the standpoint of this research. The last, drawing a conclusion and providing suggestions from the research findings and data interpretation.

RESULTS AND DISCUSSION
The results of this study highlight three main findings based on the formulated research questions. They are the use of thematic structure in the research articles published in Scopusindexed international journals, the use of thematic progression in the texts and the relationship between thematic structure and thematic progression in achieving the texts' coherence. Each of them is explained below.

The Use of Thematic Structure in the Texts
The findings to answer the first research question revealed that the three types of thematic structure formulated by Hallliday and Matthiessen (2014) (i.e. topical, interpersonal, and textual theme) are applied in the texts with a different number of occurrences. The findings concerning the use of thematic structure in the texts are outlined in Table 1. As illustrated in Table 1, the textual theme is the most frequent theme used. It occurs 1708 times out of 3426 clauses. The massive use of the textual theme indicates the authors' ability in developing the logical relationship between clauses that make their texts more cohesive and coherent. This phenomenon meets Halliday and Matthiessen's (2004;2014) theory that textual themes help structure a text by developing links to other clauses as well as signal the coherence of the text. Likewise, textual themes do cohesive work in relating the clause to its context (Eggins, 2004, p.305). Moreover, this also supports Butt et al. (2000), arguing that being able to control the use of textual themes will make their use critical to the organization of texts to achieve their purpose effectively by shaping and structuring the texts.
Furthermore, the textual theme found in this study is applied and indicated by the use of conjunctive adjuncts and conjunctions, while none of the continuatives is used. The non-existence of continuatives in the texts may be because they are commonly used in spoken texts. This has been postulated by Eggins (2004) "continuity adjuncts are used in spoken dialogue to indicate the speaker's contribution to what a previous speaker has said in an earlier".
Different from the textual theme, the interpersonal theme is the rarest type of theme found. The occurrence of this theme in the entire texts is only 69 times. This finding detects that the authors rarely use interpersonal elements such as modal/comment adjuncts and vocatives in their texts. This also confirms Eggins (2004) and Butt et al. (2000) assertion that interpersonal theme commonly occurs in conversation or spoken interaction. The finding also corroborates the previous studies' findings that the interpersonal theme is rarely found in written texts. The rarity was expected, as it is only needed to foreground the writer's position, judgement, or comment.
Additionally, the analysis results also show that the interpersonal themes are realized only in the form of modal adjuncts and finite or interrogative clauses, while none of the vocatives is used. This may be because the vocatives which are names or nicknames to address someone (Gerot & Wignell, 1994) are rarely or even almost never used in written formal academic writing, e.g. research articles.
Another finding related to the use of the interpersonal theme is that the interpersonal theme comes before the topical theme. This supports Halliday and Matthiessen's (2014) affirmation that the interpersonal theme occurs before the topical theme. It is the constituent of the Mood label which appears at the beginning of a clause (Eggins, 2004).
Moving toward the last thematic structure type applied, the topical theme takes the part as the second dominant thematic structure used in the texts with the number of occurrences 1649 times of the total. The frequent use of the topical theme detects that the authors write effectively orient the readers to what their texts are about. The topical theme is broken down into two types, i.e. the unmarked and marked topical theme. Dealing with the employment of the topical themes, this study found that the topical themes are dominated by the unmarked topical theme (1221 times). The frequent occurrence of the unmarked topical theme implies that the authors prefer to start their message by initiating the subject at the beginning of the clauses. In other words, it indicates that the authors prefer to put the subject in the initial position. It confirms what Gerot and Wignell (1994), Eggins (2014), Thompson (2014), and Halliday and Matthiessen (2004;2014) postulate that in unmarked topical theme the subject is the theme of the clause.
To conclude, the findings on the use of thematic structure show that the three types of thematic structure are applied in the texts. The textual theme is the most dominant theme occurring in the texts (1708 times) followed by the topical theme (1649 times). Meanwhile and the interpersonal theme is rarely employed (69 times). The findings not only corroborate the relevant theories but also show contradictions to the previous studies' findings specifically in terms of the dominant theme type found in the study.

The Use of Thematic Progression in the Texts
The findings to answer the second research question reports that the three patterns of thematic progression proposed by Eggins (2004) are applied in the texts. The patterns include the theme reiteration, the zig-zag, and the multiplerheme pattern. The realization of the progression patterns contribute to the texts' cohesion and coherence as it maintained the flow of information development. The findings concerning the use of thematic progression are outlined in Table 2.  Table 2 presents that the theme reiteration pattern is dominantly used in the texts. Simply put, the theme reiteration pattern outnumbers the two other patterns (the zig-zag and the multiplerheme pattern) with the number of occurrences 480 times. The tremendous use of the theme reiteration pattern implies that the authors successfully maintain the focus of the texts by reiterating the thematic constituent of the former clause in the subsequent clause (Eggins, 2004).
The finding revealing the outnumbering of theme reiteration pattern is in harmony with some earlier studies' findings focusing on the research articles (e.g. Alboghobeish & Sedghi, 2014;Rahmawati & Kurniawan, 2015;Ebrahimi (2016); Muroda et al., 2018). These studies figured out that theme reiteration patterns or constant themes dominated the thematic progression patterns employed in the texts.
Contrariwise, the zig-zag pattern is rarely employed in the texts, occurring 344 times. The realization of the zig-zag pattern indicates that the authors are able to manage the given-new information in building relations between clauses This pattern creates a smooth flow of information development in the texts (Thompson, 2014). Moreover, it contributes to the texts' cohesiveness and coherence and gives the texts make a sense of continuous development by building on the newly preceding information. Thus, the employment of the zig-zag pattern in the texts commits to achieve the texts' cohesion by shifting a rheme element of the earlier clause to be a theme of the subsequence clause.
The last thematic progression pattern used in the texts is the multiple-rheme pattern. This pattern comes up as the second dominant pattern used after the theme reiteration pattern. This finding brings a novelty to the relevant studies which have the same focus on written texts (e.g. Alboghobeish & Sedghi, 2014; Rahmawati & Kurniawan, 2015;Al Bakaa, 2015;Yuned, et al., 2016;Gunawan & Aziza, 2017;Na-on & Jaturapitakkul, 2017;Herdiawan, 2018;and Lestari et al., 2019), discovering that the multiplerheme pattern (also called as split rheme by Danes, 1974) is the rarest or least pattern found in the texts.
The existence and the frequent occurrences of the multiple-rheme pattern may signal the authors' ability to develop texts according to the prior plan. They successfully express their focus at the rheme of one clause to be described consecutively as the themes in the subsequent clauses. This affirms what Eggins (2004) expounds that the multiple-rheme rheme pattern often provides the underlying organizing principle for a text, with both zig-zag and theme reiteration strategies used to elaborate the thematic points. Moreover, the multiple rheme pattern organizes the texts in a way that creates readers' expectations towards what information will follow in the paragraphs since this pattern allows the readers to predict what would come next.
However, another finding on the thematic progression analysis, reveals that there are also clauses that do not form any thematic progression pattern. Since no expert has named the clauses that did not form any thematic progression pattern, in this study they are labelled as empty progression. The empty progression means that the clauses in the text are not developed from the previous theme or rheme constituent. As a result, it stopped the succession of progression chains that could affect in lessening of the texts' coherence.
Despite that, on the whole, this present study shows that the three progression patterns are used in the texts that contribute to the texts' coherence by maintaining the flow of information and the information development so that the texts meet the readers' expectations. From the analysis, the existence of thematic structure and thematic progression patterns in the texts may emerge the following up question about the relationship between them in achieving the texts' coherence.

Texts' Coherence
To answer the third research question about the relationship between thematic structure and thematic progression to achieve the textual coherence of the texts, in analyzing the data, this present study was referring to the logical relations taxonomy proposed by Thornbury (2005). The results of the analysis uncover that the relations between thematic structure and thematic progression create logical relations between clauses in the texts that achieve the texts' coherence. The logical relations are built through the realization of thematic progression patterns. These findings uphold the previous studies (e.g. Yunita, 2018thomps;Fitriati & Yonata, 2017) reporting that thematic progression built logical relationships between clauses in texts. Additionally, Fitriati and Yonata (2017) confirm that the thematic progression and its logical relations made the texts make sense.
The relationship between topical theme and the thematic progression patterns create the logical relations called additive, showing the relations of addition, and exemplification. More specifically, the relations between them appear frequently to provide examples and give details about or specify the statement of the earlier clause or sentence. Nevertheless, the analysis results also pointed out that the logical relations showing the relationship between the topical theme and thematic progression patterns are not explicitly implied through conjunctive adjuncts or linking devices. This confirms Thornbury's (2005) statement that there are lexical clues that tie the texts together; however, there are also implicit logical connections that help create the feeling that the texts make sense in which the logical connections are the same as the linking devices, but no explicit conjuncts were signalling the relation.
Moving on to the relationship between the interpersonal theme and the three thematic progression patterns, the results showed that they construct the logical connections between clauses through the additive relations (addition and emphasis). The logical relations constructed are realized in the form of modal adjuncts and finite or interrogative forms. The modal adjuncts built the relations of emphasis since they are used to emphasize the statement in the clauses as well as to show validations. Meanwhile, the finite or interrogative clauses represented the relations of addition since they are realized to specify and describe in detail the constituent of the previous clause. Moreover, the realization of the interpersonal theme is accompanied by the use of other theme types, especially the topical themes. Specifically, the interpersonal theme comes before the topical theme.
The last relations discussed are created by the relationship between textual theme and the thematic progression patterns. In this regard, the results reveal that the four logical relations (i.e additive, adversative, causal, and temporal) suggested by Thornbury (2005) are realized. More specifically, the logical relations show the relations of addition, exemplification, similarity, contrast, cause, effect, the sequence in time, and sequences. The realization is through the use of conjunctive adjuncts and conjunctions that belong to the textual theme elements. This is why the relationship between textual theme and the thematic progression express all the logical relations proposed, that both textual elements (conjunctive adjuncts and conjunctions) contribute to the texts' coherence a lot. This corroborates what Thornbury (2005) argues that the logical connections between clauses can be viewed from the conjunctions or conjuncts that link the sentences in which the conjuncts can also express several different categories of logical relation between parts of a text. In the same vein, Eggins (2004), Thompson (2014), and Halliday and Matthiessen (2014) postulate that the logical relations or connections can be viewed from the linking devices that tie the clauses together, including conjunctive adjuncts and conjunctions.
As has been mentioned formerly, that this study found the textual theme is massively used in the texts. It means that the textual elements support the cohesion and the coherence of the texts a lot by constructing logical relations or connections to tie and hang the texts together. Hence, the use of logical connections can create make sense texts (Thornbury, 2005). Thus, the texts meet the readers' expectations.
To sum up, the relation between thematic structure and thematic progression build logical relations between clauses and sentences in achieving the texts' coherence. The relations between the topical theme and thematic progression patterns show the additive relations (addition and exemplification), interpersonal and the thematic progression patterns build the additive relations (addition and emphasis), and textual theme and thematic progression patterns create the four logical relations (i.e. additive, adversative, causal, and temporal).

CONCLUSIONS
Overall, this study reports that the relationship between thematic structure and thematic progression supports the textual coherence of the research articles published in Scopus-indexed international journals. The results of this study are highlighted in three major findings. Firstly, in terms of the use of thematic structure, this study reports that the three types of thematic structure are used. The textual theme is the most frequent theme used in the texts, followed by the topical and the interpersonal theme. Secondly, in terms of the use of thematic progression, the three types of thematic progression patterns are realized. The theme reiteration pattern is dominantly applied in the texts, followed by the multiple-rheme pattern and the zig-zag pattern. The second dominant use of the multiple-rheme pattern brings a new insight or discovery in the relevant research field. Thirdly, the relationship between thematic structure and thematic progression constructs logical relations between clauses or sentences in achieving the texts' coherence. The relations imply that the authors construct the textual cohesion and coherence of the texts through the use of cohesive relationships (textual themes) to relate and tie ideas in the texts, the use of semantic ties (topical theme) to construct the contextual frame in the texts, the use of interpersonal constituents (interpersonal theme) to personal construe ideas or opinions, the use of theme reiteration afford strong and clear focus of the texts, the use of the zig-zag pattern to give a sense of cumulative development of the texts, and the use of the multiple-rheme pattern to uphold the coherency of the texts. In the end, the findings are expected to give profound contributions to English students, English teachers/lecturers, and other fellow writers or researchers to develop and conduct further research related to thematic structure and thematic progression.
Finally, anything considered, a number of suggestions are provided for the development of the teaching of English as a second/foreign language as the pedagogical implications of this present study. Firstly, thematization in SFL (i.e. thematic structure and thematic progression) needs to be applied in EFL writing classes to foster students' writing skills through utilizing structural forms of functional linguistics and to enable the students to create a cohesive and coherent text. Secondly, the thematization or theme management should be exposed through modeling and construction activities. The teachers should provide sufficient and appropriate models of texts such as highlyindexed articles to be explored by students to help them understand the functions of thematization in producing a well-structured meaningful text. Lastly, thematization should be taught explicitly to make the students aware of the pivotal role thematization plays in writing.