1、研究生如何撰寫高水平的學(xué)術(shù)論文,導(dǎo)言,為什么要撰寫學(xué)術(shù)論文？,一篇高水平的學(xué)術(shù)論文包括哪些要素？,如何撰寫高水平的學(xué)術(shù)論文？,在撰寫學(xué)術(shù)論文過程中的科研道德問題,一、為什么要撰寫學(xué)術(shù)論文？,為什么要撰寫學(xué)術(shù)論文？,基礎(chǔ)研究的成果以論文形式表現(xiàn) 研究結(jié)果只有發(fā)表了，他人才能重復(fù)、驗(yàn)證，結(jié)果才可能成為知識(shí) 提供書面材料讓同行知道：做了什么？為什么這樣做？怎樣做的？發(fā)現(xiàn)了什么？發(fā)現(xiàn)意味了什么？ 撰寫和發(fā)表論文是科研工作的最后一道工序 發(fā)表論文的質(zhì)量與數(shù)量：衡量水平和效率的客觀標(biāo)準(zhǔn),二、一篇高水平的學(xué)術(shù)論文包括哪些要素？,創(chuàng)新性 可讀性 信息量 參考文獻(xiàn) 署名與致謝,科技論文的五要素,創(chuàng)新性,創(chuàng)新是一

2、種科學(xué)發(fā)現(xiàn) 二十世紀(jì)初量子論誕生； 四十年代末至五十年代初發(fā)明晶體管； 五十年代發(fā)現(xiàn)DNA雙螺旋結(jié)構(gòu) 八十年代末PCR技術(shù)的發(fā)明,創(chuàng)新性,Nature：創(chuàng)新是科研成果新穎，引人注意（出人意料或令人吃驚），而且該項(xiàng)研究看來在該領(lǐng)域之外具有廣泛的意義，無論是報(bào)道一項(xiàng)突出的發(fā)現(xiàn)，還是某一重要的問題的實(shí)質(zhì)性進(jìn)展的第一手報(bào)告，均應(yīng)使其他領(lǐng)域的科學(xué)家感興趣。 Science：創(chuàng)新是指對(duì)自然或理論提出新見解，而不是對(duì)已有研究結(jié)論的再次論證，內(nèi)容激動(dòng)人心并富有啟發(fā)性，具有廣泛的科學(xué)興趣。具體而言，就是說在已沉寂的研究領(lǐng)域提出創(chuàng)新思想；在十分活躍的研究領(lǐng)域取得重大進(jìn)展或者是將原先彼此分離的研究領(lǐng)域融合在一起。,

3、創(chuàng)新性,如何體現(xiàn)創(chuàng)新：一篇論文或一項(xiàng)研究課題，規(guī)模不一定很大，但研究一定要深入，結(jié)論一定要深刻，要能反映研究者獨(dú)到的見解。,可讀性,Nature：來稿應(yīng)清楚、簡(jiǎn)練，以便讓其他領(lǐng)域的讀者和母語為非英語的讀者能夠讀懂。 在投稿之前，請(qǐng)從事其他學(xué)科研究的同事對(duì)最終文稿在清楚易懂方面提供意見往往很有用。 Nature的編輯常常建議修改并重寫論文的摘要和引言 保證文章和圖片對(duì)非該領(lǐng)域的讀者明確、能讀懂。 Nature一再申明：凡不符合他們要求的稿件，毋需深入閱讀即行退稿。,本世紀(jì)初，Hilbert由于提出23個(gè)數(shù)學(xué)難題而名聲大振。 何謂一個(gè)好的數(shù)學(xué)選題？“清晨當(dāng)你漫步時(shí)，能向你遇到的第一位行人用10分鐘

4、時(shí)間解釋清楚的數(shù)學(xué)選題” 簡(jiǎn)明、清楚、易懂！ 可讀性：使讀者能夠明了你要說的什么問題，是怎樣著手解決的，并不需要讀者非得全面理解你的論文的全部?jī)?nèi)容。,什么是可讀性,可讀性包括：,結(jié)論的可靠性：實(shí)質(zhì)性進(jìn)展？階段性成果的指導(dǎo)意義？ 構(gòu)思的嚴(yán)密性和寫作的邏輯性：解釋學(xué)術(shù)思想，介紹研究背景 論述的生動(dòng)性： 文字和圖表的規(guī)范性：數(shù)據(jù)的取舍和圖表的設(shè)計(jì) 論文格式的標(biāo)準(zhǔn)性：嚴(yán)格按照Guide for authors,信息量,Chinese Physics Letters：“要盡可能多地給出有關(guān)研究的信息，盡可能少地運(yùn)用investigate（調(diào)查），Study（研究），discuss（討論）等詞。 如：“T

5、he acid concentration is 25 g/L 就比“The acid concentration is measured”包含更多的信息量。 避免或少使用“it is shown, it is obvious”等冗余詞語,信息量,讀之前或者不知道，或者模糊不清或者不確切的知識(shí)，在讀過該文之后不僅獲得新知識(shí)，還消除了模糊不清或不確切之處，就說明這篇文章包含較多的信息量。 如：“多點(diǎn)測(cè)量”的信息量要比“6點(diǎn)測(cè)量”少得多，前者給出的是模糊的、不確切的信息，而后則是清楚的、確切的信息,論文篇幅的限制,新的學(xué)術(shù)思想，實(shí)驗(yàn)，發(fā)現(xiàn)等結(jié)果決定論文信息量 篇幅的嚴(yán)格限制，可刪除那些與文章主題關(guān)

6、系不大的或次要的內(nèi)容 篇幅限制：重新構(gòu)思論文的框架，選擇最重要的素材，采納最恰當(dāng)?shù)谋硎龇绞讲?duì)文字的敘述仔細(xì)推敲。 Watson與Crick發(fā)現(xiàn)DNA雙螺旋結(jié)構(gòu)的論文發(fā)表在Nature，只有約500字和一幅DNA的雙螺旋圖；這篇論文使作者獲得了諾貝爾生物醫(yī)學(xué)獎(jiǎng)。,參考文獻(xiàn),SCI(Science Citation Index)：美國(guó)賓州的科學(xué)信息研究所（Institute for Scientific in formation，ISI） 按論文被引用的次數(shù)來評(píng)價(jià)研究成果的思想 SCI它除了收錄論文的作者、題目、源期刊、摘要、關(guān)鍵詞之位外，還將論文所列的參考文獻(xiàn)全部收錄下來，可以勾畫一篇論文同其

7、他論文之間的學(xué)術(shù)聯(lián)系,期刊的影響因子,期刊的影響因子（Impact Factor，IF）：某一期刊在連續(xù)兩年內(nèi)發(fā)表的論文總數(shù)為A，第三年它被引用的次數(shù)為B，影響因子IF=B/A，意指該刊兩年內(nèi)所發(fā)表的論文在第三年被引用的平均次數(shù)，反映了該期刊在世界范圍內(nèi)的影響。 在不同刊物上發(fā)表文章其難易程度相差可能很大，參考文獻(xiàn)對(duì)計(jì)算影響因子和評(píng)價(jià)論文水平所引起的巨大作用。 不能脫離學(xué)科分類來看IF。,如何列舉參考文獻(xiàn),一定要將產(chǎn)生新的學(xué)術(shù)思想之前最重要的文獻(xiàn)列舉出來，說明當(dāng)時(shí)的研究所達(dá)到的水平； 在研究工作開展中，受哪些文獻(xiàn)資料的啟發(fā)，從哪些論文中獲得了教益，促進(jìn)了研究進(jìn)度，屬于這類的文獻(xiàn)均應(yīng)列出。 寫論

8、文時(shí)應(yīng)對(duì)論文涉及的學(xué)科內(nèi)容進(jìn)行檢索，看看是否遺漏了重要的相關(guān)文獻(xiàn)。,列出參考文獻(xiàn)的重要性,編輯和審稿人根據(jù)參考文獻(xiàn)，初步判斷該論文的水平以及作者對(duì)有關(guān)學(xué)科的背景知識(shí)水平 在一定程度上也可以判斷作者的科學(xué)道德，如果未能列出密切相關(guān)的主要文獻(xiàn)，讀者、編輯和審稿人可能會(huì)看作是一種不良學(xué)風(fēng)。參考文獻(xiàn)關(guān)系到論文的可信度和作者的聲譽(yù)。 國(guó)內(nèi)一些低檔次期刊對(duì)參考文獻(xiàn)極不重視。,國(guó)內(nèi)的主要問題,1、為了省事，轉(zhuǎn)引二手文獻(xiàn)，既不核對(duì)，自己也沒有看過或?yàn)g覽過 2、只引自己的論文，是自負(fù)又是無知的表現(xiàn)。 3、閱讀的是中文文獻(xiàn)，引用的是外文文獻(xiàn)。 4、引用文獻(xiàn)中近三年之內(nèi)的比例少。,署名和致謝,優(yōu)秀科技論文的署名反映

9、了作者的科學(xué)道德，應(yīng)經(jīng)得起時(shí)間的考驗(yàn)。論文作者和參與工作的人應(yīng)區(qū)別開。 致謝：國(guó)內(nèi)一般是感謝基金支持。課題組的集體力量、同行的學(xué)術(shù)交流等等都應(yīng)當(dāng)致謝。 致謝不是可有可無。論文公開發(fā)表后，就用書面形式記載了你的科研成果，同時(shí)也記下了你的科研道德，,三、如何撰寫高水平的學(xué)術(shù)論文？,What is the major question addressed in this paper? Is this question important and why? What are the approaches used in this paper, and whether they are adequate

10、 for the questions? What are the novel idea or using innovative approaches? What is the concept coming out of this paper? Do the results presented support this new concept?,怎樣閱讀科技論文,Introduction, Methods, Results, and Discussion (IMRAD) I: What and why? 研究什么問題？為什么研究這個(gè)問題？ M：How? 如何研究的？ R：What? 發(fā)現(xiàn)了什么？

11、 D：What? 發(fā)現(xiàn)意味著什么？,科技論文的基本結(jié)構(gòu),重要性 體現(xiàn)創(chuàng)新點(diǎn) 包含所有關(guān)鍵詞 吸引人 用動(dòng)詞、句子,Important/significant Unexpected/unusual Functional Simple Straight forward Specific,標(biāo)題,最好不用“的研究”、“的意義”、“的發(fā)現(xiàn)” 、“的特征”、“的討論” 、 “的分析”等詞；某某問題的研究、初步研究 用論文中的主要結(jié)論作為標(biāo)題,寫文章的目的 研究過程和使用的方法 主要結(jié)果和結(jié)論。基礎(chǔ)研究應(yīng)體現(xiàn)創(chuàng)新，但不宜過分強(qiáng)調(diào)；應(yīng)用研究要提出應(yīng)用前景。 不要把文中內(nèi)容照搬 重要事實(shí)開頭，避免第一人稱或輔助

12、從句 過去時(shí)敘述作者工作，現(xiàn)在時(shí)表達(dá)主要結(jié)論 效果：國(guó)外同行根據(jù)英文摘要和圖表，可以大致看懂全文。,摘要,前言,(1)“為什么要做?” 簡(jiǎn)要回顧本文所涉及到的科學(xué)問題的研究歷史，闡述本課題的研究目的。 (2)“別人做了什么工作? 存在什么問題?” 應(yīng)當(dāng)對(duì)國(guó)內(nèi)外在本課題上的研究作一總結(jié)。總結(jié)用表的形式比較好，再輔以適當(dāng)?shù)恼撌?。不要引一大堆參考文獻(xiàn)，要引自己看過的參考文獻(xiàn)，這一點(diǎn)請(qǐng)?zhí)貏e注意。 (3)“準(zhǔn)備做什么?” 針對(duì)他人研究工作中存在的問題，提出自己的思路和研究?jī)?nèi)容，扼要交代本研究所采用的方法和技術(shù)手段等，強(qiáng)調(diào)研究的重要性。,丙酮酸作為一種重要的工業(yè)原料，不僅在化工、制藥及農(nóng)用化學(xué)品工業(yè)中有著

13、廣泛的用途，在食品保健業(yè)也具有巨大的市場(chǎng)潛力。最近，廣東太陽(yáng)神集團(tuán)以丙酮酸鈣制成減肥膠囊即為一例。日益增長(zhǎng)的市場(chǎng)需求，使得研究者對(duì)發(fā)酵法生產(chǎn)丙酮酸的興趣不斷增大1。（為什么要做） 球擬酵母(Torulopsis)的維生素營(yíng)養(yǎng)缺陷型具有大量積累丙酮酸的潛力，曾有一些學(xué)者研究過溶氧對(duì)其產(chǎn)酸性能的影響。Miyata和Yonehara認(rèn)為供氧不足會(huì)造成丙酮酸產(chǎn)量下降，而乙醇產(chǎn)量顯著增加2；Hua和Shimizu等則利用代謝通量分析方法研究了不同溶氧水平下Torulopsis glabrata胞內(nèi)的代謝流分配3,4。作者在前期工作中也發(fā)現(xiàn)，較高的溶氧有利于丙酮酸的積累5。（別人做了什么工作?）但是，若要

14、實(shí)現(xiàn)丙酮酸發(fā)酵過程高產(chǎn)量、高產(chǎn)率和高生產(chǎn)強(qiáng)度的統(tǒng)一，溶氧應(yīng)當(dāng)高到什么程度，在發(fā)酵過程中應(yīng)當(dāng)采取何種控制策略，這是已有文獻(xiàn)尚未闡明的問題。（存在什么問題?） Torulopsis glabrata WSH-IP12是一株能夠積累丙酮酸的多重維生素營(yíng)養(yǎng)缺陷型6。作者對(duì)其進(jìn)行誘變改良，獲得了一株產(chǎn)丙酮酸性能更佳的T. glabrata突變株WSH-IP3037。在優(yōu)化了培養(yǎng)基中維生素濃度的基礎(chǔ)上8，本文首先分析了不同體積傳氧系數(shù)下(溶氧均高于50%)WSH-IP303發(fā)酵的動(dòng)力學(xué)特征，根據(jù)主要?jiǎng)恿W(xué)參數(shù)(m、qs和qp)的變化特性提出了分階段供氧控制模式。然后，實(shí)驗(yàn)驗(yàn)證了該模式在實(shí)現(xiàn)丙酮酸高產(chǎn)量和高

15、產(chǎn)率的統(tǒng)一上的有效性，并對(duì)不同供氧方式下細(xì)胞的代謝活性進(jìn)行了討論。（準(zhǔn)備做什么?）,舉例,Glutathione (g-GluCysGly, reduced form GSH ) is the major non-protein thiol compound in living cells, including human, yeast and bacterial cells. In contrast to the extensive study of the cellular functions of GSH in eukaryotic cells, relatively little is

16、 known about GSH in prokaryotes, except for Escherichia coli. In this organism GSH was found to be involved in the resistance to osmotic stress (23), oxidative stress (4, 24) and toxic electrophiles (9). Fahey et al. (7) reported that GSH was found in many gram-negative bacteria but was lacking in m

17、ost of the gram-positive bacteria, except Lactococcus lactis and Streptococcus agalatiae. Those organisms were thought to synthesize GSH, since the total intracellular amount was much higher than the total amount detected in the medium. Subsequently, Newton et al. (17) concluded that streptococci an

18、d enterococci must have the capacity to synthesize GSH, because the high GSH content of those strains, up to 11 micromole per gram of dry cell, could not be exclusively achieved by import of GSH from medium. However, these authors did not measure the activities of g-glutamylcysteine synthetase and g

19、lutathione synthetase, which would have supplied direct evidence for the existence of a glutathione biosynthetic system. On the other hand, by supplementing 35SCys and 35SGSH in chemically defined medium, Wiederholt and Steele (29) showed that L. lactis ssp. cremoris Z8 takes up GSH efficiently from

20、 the medium but is unable to synthesize it, whereas strain C2 could neither import nor synthesize GSH.,In this study we aim to characterize GSH accumulation and its role in lactic acid bacteria. Defined starter cultures of L. lactis are of great economic importance in the bulk production of Cheese.

21、As a facultative anaerobe, strains of L. lactis very often encounter a challenge from oxygen and they have evolved several systems, e.g. NADH oxidase/NADH perosidase system, to survive this challenge (6). The glutathione-dependent reduction system is responsible for maintaining the reduced environme

22、nt and plays an important role against oxidative stress in E. coli and S. cerevisiae (4). However, the physiological role of GSH in L. lactis, or even in gram-positive bacteria, remains unknown except that Sherrill and Fahey (22) found the cellular glutathione of Streptococcus mutans ATCC 33402 prot

23、ected cells against growth inhibition caused by a specific thiol oxidizing agent diamide. We therefore examined the presence of GSH and glutathione-dependent enzymes, e.g. glutathione reductase (GR), in different strains of L. lactis. All the subspecies of dairy L. lactis were unable to synthesize G

24、SH but some strains could import it from the medium. In addition, glutathione reductase was observed to be a ubiquitous enzyme in L. lactis, and the activity of this enzyme was sensitive to oxygenation. Using L. lactis SK11 as a model strain, we demonstrated that stationary phase cells with intracel

25、lular GSH had a strong resistance against H2O2 treatment compared to cells without intracellular GSH, which exhibited as a high survival and a shortened lag phase as well. Furthermore, the lag phase difference upon H2O2 treatment was found to be dependent on the ability to take up glutathione in the

26、 16 tested strains of L. lactis. To our best knowledge, this is the first report with respect to a clear physiological role of glutathione in lactic acid bacteria. In addition, our insights on the presence and protection role of GSH in L. lactis could be applied to dairy industry, e.g. screening L.

27、lactis which could take up glutathione as a starter for cheese production.,材料與方法,材料與方法是論文中非常重要的一個(gè)環(huán)節(jié)。國(guó)外期刊對(duì)此尤其重視，國(guó)內(nèi)限于文章篇幅，對(duì)此要求不是很嚴(yán)格。 材料與方法讓他人看到你的論文后能重復(fù)研究工作。,結(jié)果,在結(jié)果的開始部分簡(jiǎn)單介紹原理和實(shí)驗(yàn)?zāi)康?按照?qǐng)D表，看圖說明，描述具體結(jié)果。不能遺漏，按照結(jié)果在正文和圖表中的邏輯順序。 實(shí)驗(yàn)結(jié)果的順序，絕不是按獲得數(shù)據(jù)的先后排列，而是要按企圖說明問題的邏輯順序排列。 要學(xué)會(huì)合理使用圖、表和文字說明。 要敢于舍棄不必要的數(shù)據(jù)！,What do we

28、learn from this research? 概括主要發(fā)現(xiàn)，不要重復(fù)前言和結(jié)果 引用可以支持你的文章，但不會(huì)影響或降低文章的創(chuàng)新性 主要缺點(diǎn)（或局限性）是什么？為什么？ 不要做太多假設(shè)，不要夸大不能被實(shí)驗(yàn)數(shù)據(jù)完全支持的結(jié)論 在文章的最后突出研究的重要性！,討論,The results in the present study may have a number of implications in the cell biology of tyrosine kinase receptors. First, we report the . To our knowledge, this is

29、the first demonstration for . Thus, our results suggest a cross-talk between Ca2+ and tyrosine kinase signaling pathways. Second, the present study reveals an important regulatory effect of . It will be interesting to determine whether . Finally, we show that . Xxx . Taken together, these results su

30、ggest a general role of tyrosine kinase in the endocytosis of growth factor receptors.,There are three main findings in the present study. First, we report a GDNF-induced long-term facilitation of neurotransmitter release at the neuromuscular synapses. Second, we show that the effect of GDNF on syna

31、ptic transmission is mediated by an increase in the expression of the Ca2+-binding protein frequenin. Finally, we demonstrate that GDNF and frequenin facilitate synaptic transmission by enhancing N-type Ca2+ channel activation, leading to an enhancement of Ca2+ influx. Thus, this study has identifie

32、d, for the first time, a molecular target that mediates the long-term, synaptic action of a neurotrophic factor. Our findings may also provide new insights into the regulatory mechanisms of neurotransmitter release.,舉例,圖,FIG. 2 Growth curves of L. lactis SK11 in the absence (open symbols) or the pre

33、sence (closed symbols) of 0.2 mM GSH. An overnight CDM culture was inoculated into fresh CDM supplemented with or without GSH with an inoculum size of 5% (v/v). The sample identifications (A, B, C, D, E, and F) were used to denote the growth phases, at which samples were withdrawn for investigating

34、the H2O2 resistance (FIG. 3),表,參考文獻(xiàn),朱日祥, 劉春, 朱崗昆. 極性倒轉(zhuǎn)頻率及其分布規(guī)律. 科學(xué)通報(bào), 1990, 35(4)：374-375 Watts D R, Watts G C, Bramall A M. Cretaceous and Early Tertiary paleomagnetic results from the Antarctic Peninsula. Tectonics, 1984, 3(3)：333-346 英語名字的三種規(guī)范：“Yin Li”, “LI Yin”, “Li, Yin” Li Y, Chen J, Lun S. Li

35、, Y., Chen, J., Lun, S. Li, Y., J. Chen, and S. Lun.,導(dǎo)師和學(xué)生討論論文的基本構(gòu)思、框架、插圖；學(xué)生說明其實(shí)驗(yàn)結(jié)果的創(chuàng)新點(diǎn)；決定投寄何種雜志。 學(xué)生向?qū)熖峁┡c該課題有關(guān)的主要綜述和原始論文（2030篇）。 由學(xué)生本人撰寫論文的初稿，送交導(dǎo)師。,論文撰寫的程序,導(dǎo)師對(duì)初稿作出評(píng)論；請(qǐng)學(xué)生補(bǔ)充實(shí)驗(yàn)數(shù)據(jù)，并提出修改意見，但通常并不立即修改。 參考導(dǎo)師評(píng)論和修改意見，學(xué)生撰寫第二稿，送交導(dǎo)師。 導(dǎo)師在第二稿基礎(chǔ)上進(jìn)行修改，部分內(nèi)容完全重寫，交回學(xué)生，請(qǐng)學(xué)生提出修改意見（用不同字體標(biāo)明），形成第三稿。,論文撰寫的程序,導(dǎo)師與學(xué)生對(duì)第三稿進(jìn)行討論后，由

36、導(dǎo)師擬就第四稿，交回學(xué)生再評(píng)論和修改。 對(duì)學(xué)生的評(píng)論和修改意見作認(rèn)真考慮后，擬就第五稿（半定稿），請(qǐng)學(xué)生評(píng)論、修改。 導(dǎo)師最后定稿（第六稿），并對(duì)英文作仔細(xì)潤(rùn)色。 由學(xué)生嚴(yán)格按投寄雜志的要求整理定稿、送審。,論文撰寫的程序,高水平期刊的審稿程序,Pre-submission inquiry Submit/cover letter Initial screen Send out for reviews Reject/soft reject/revise Rebuttal Revise again Accept,significance/importance original and innova

37、tive Solid and rigorous unusual/surprising general interests,Initial screening,You,Editors,main findings significance suggested reviewers “not to review” list who have read,投稿信,Be calm about reviewers criticisms. Always make editor your friend Never argue with reviewers Try to do everything that rev

38、iewers ask Seize the opportunity when reviewers make mistakes,文章的修改,導(dǎo)師和學(xué)生對(duì)評(píng)審意見逐條進(jìn)行討論，決定如何答復(fù)，是否需作補(bǔ)充實(shí)驗(yàn)。 由學(xué)生擬出答復(fù)意見。,如何答復(fù)修改意見,文章未審就退稿,Dear Editor, I would appreciate if you could reconsider to review our manuscript, “111. We feel strongly that this is an important subject that touches one of the central

39、 dogmas in neuroscience: xxx. It is also very timely, given the publication of the paper by X and Y entitled “222” in the latest issue of Nature Neuroscience. In this paper, the authors xxx. They claimed that xxx. When a paper this provocative has been published by a high profile journal like Nature

40、 Neuroscience, we believe that it is worth giving a benefit of doubts. It will be helpful if there are papers that consider other alternative interpretations, or attempt to replicate in the same or different systems. We have observed similar xxx, but we have a completely different interpretation. We

41、 found that 1) xxx 2) xxx; 3) xxx. Thus, our paper raises the possibility that xxx reported by X and Y were due to xxx. Specifically, we would like you to consider the following two issues: First, X and Y used aaa, while we used bbb. sssssssss. Second, ccc used by X and Y may not be so specific. In

42、addition to the drastically different opinions regarding xxx, we feel that our findings on xxx is also significant in yyy and will be of interests to general readers of Nature Neuroscience. We therefore did not write our paper to directly challenge the paper by X and Y. However, we will be willing t

43、o re-write the paper in ways you think that will help debate on this important issue.,Dear Dr. xx, We received with some surprise your letter of November 4, rejecting this manuscript on the basis of one reviewers opinion which you “found persuasive”. We wish to indicate our dissatisfaction with this reviewers comments, which appear to ignore the new experiments submitted as part of the revised manuscript. This reviewer states: “111.” This was precisely the point of the xxx experimen