第二产业完成增加值342亿元,同比增长38%;第三产 …

第1章 绪论1.1 简述下列术语：数据，数据元素、数据对象、数据结构、存储结构、数据类型和抽象数据类型。

解：数据是对客观事物的符号表示。

在计算机科学中是指所有能输入到计算机中并被计算机程序处理的符号的总称。

数据元素是数据的基本单位，在计算机程序中通常作为一个整体进行考虑和处理。

数据对象是性质相同的数据元素的集合，是数据的一个子集。

数据结构是相互之间存在一种或多种特定关系的数据元素的集合。

存储结构是数据结构在计算机中的表示。

数据类型是一个值的集合和定义在这个值集上的一组操作的总称。

抽象数据类型是指一个数学模型以及定义在该模型上的一组操作。

是对一般数据类型的扩展。

1.2 试描述数据结构和抽象数据类型的概念与程序设计语言中数据类型概念的区别。

解：抽象数据类型包含一般数据类型的概念，但含义比一般数据类型更广、更抽象。

一般数据类型由具体语言系统内部定义，直接提供给编程者定义用户数据，因此称它们为预定义数据类型。

抽象数据类型通常由编程者定义，包括定义它所使用的数据和在这些数据上所进行的操作。

在定义抽象数据类型中的数据部分和操作部分时，要求只定义到数据的逻辑结构和操作说明，不考虑数据的存储结构和操作的具体实现，这样抽象层次更高，更能为其他用户提供良好的使用接口。

1.3 设有数据结构(D,R)，其中{}4,3,2,1d d d d D =，{}r R =，()()(){}4,3,3,2,2,1d d d d d d r =试按图论中图的画法惯例画出其逻辑结构图。

解：1.4 试仿照三元组的抽象数据类型分别写出抽象数据类型复数和有理数的定义（有理数是其分子、分母均为自然数且分母不为零的分数）。

解：ADT Complex{ 数据对象：D={r,i|r,i 为实数} 数据关系：R={<r,i>} 基本操作： InitComplex(&C,re,im)操作结果：构造一个复数C ，其实部和虚部分别为re 和imDestroyCmoplex(&C)操作结果：销毁复数CGet(C,k,&e)操作结果：用e返回复数C的第k元的值Put(&C,k,e)操作结果：改变复数C的第k元的值为eIsAscending(C)操作结果：如果复数C的两个元素按升序排列，则返回1，否则返回0IsDescending(C)操作结果：如果复数C的两个元素按降序排列，则返回1，否则返回0Max(C,&e)操作结果：用e返回复数C的两个元素中值较大的一个Min(C,&e)操作结果：用e返回复数C的两个元素中值较小的一个}ADT ComplexADT RationalNumber{数据对象：D={s,m|s,m为自然数，且m不为0}数据关系：R={<s,m>}基本操作：InitRationalNumber(&R,s,m)操作结果：构造一个有理数R，其分子和分母分别为s和m DestroyRationalNumber(&R)操作结果：销毁有理数RGet(R,k,&e)操作结果：用e返回有理数R的第k元的值Put(&R,k,e)操作结果：改变有理数R的第k元的值为eIsAscending(R)操作结果：若有理数R的两个元素按升序排列，则返回1，否则返回0IsDescending(R)操作结果：若有理数R的两个元素按降序排列，则返回1，否则返回0Max(R,&e)操作结果：用e返回有理数R的两个元素中值较大的一个Min(R,&e)操作结果：用e返回有理数R的两个元素中值较小的一个}ADT RationalNumber1.5 试画出与下列程序段等价的框图。

■ 特殊字符大全（GB2312）：特殊符号：·⊙①⊕◎Θ⊙●○¤㊣㈱＠の■□★☆◆◇◣◢◤◥▲△▼▽⊿◢▂▃ ▄ ▅▆▇ █ ▉▊▋▌▍▎▏■ ▓ 回□ 〓≡↑↓→←↘↙♀♂┇┅‖$ @ * & # ※卍卐∞Ψ §∮ № ⌒＊░ ▒ ▣▤▥▦▧▨▩ ▪ ▫ ▬ ◆◇◈◎ ● ◐◑☉☎☏☜☞☺☻ ☼ ♠♡♢♣♤♥♦♧☎♩ ♪ ♫ ♬♭♯ ¥标点符号：．。

，、；：？！ˉˇ¨`~ 々～‖∶＂＇｀｜·… —～- 〃‘’“”〝〞〔〕〈〉《》「」『』〖〗【】（）［］｛｝︻︼﹄﹃数学符号：＋－×÷﹢﹣±／＝∥∠ ≌ ∽ ≦ ≧ ≒﹤﹥≈ ≡ ≠ ＝≤ ≥ ＜＞≮ ≯∷ ∶ ∫ ∮ ∝ ∞ ∧ ∨ ∑ ∏ ∪ ∩ ∈ ∵ ∴ ⊥ ∥ ∠ ⌒ ⊙ √∟⊿ ㏒㏑％‰单位符号：㎎㎏㎜㎝㎞㎡㏄㏎㏑㏒㏕℡ ％‰ ℃ ℉ °′″＄￡￥￠♂♀℅数字序号：① ② ③ ④ ⑤ ⑥ ⑦ ⑧ ⑨ ⑩ ㈠㈡㈢㈣㈤㈥㈦㈧㈨㈩№⑴ ⑵ ⑶ ⑷ ⑸ ⑹ ⑺ ⑻ ⑼ ⑽ ⑾⑿ ⒀ ⒁ ⒂ ⒃ ⒄ ⒅ ⒆ ⒇⒈ ⒉ ⒊ ⒋ ⒌ ⒍ ⒎ ⒏ ⒐ ⒑ ⒒ ⒓ ⒔ ⒕ ⒖ ⒗ ⒘ ⒙ ⒚ ⒛Ⅰ Ⅱ Ⅲ Ⅳ Ⅴ Ⅵ Ⅶ Ⅷ Ⅸ Ⅹ Ⅺ Ⅻ ⅰ ⅱ ⅲ ⅳ ⅴ ⅵ ⅶ ⅷ ⅸ ⅹ希腊字母：Α Β Γ Δ Ε Ζ Η Θ Ι Κ Λ Μ Ν Ξ Ο Π Ρ Σ Τ Υ Φ Χ Ψ Ωα β γ δ ε ζ ν ξ ο π ρ σ η θ ι κ λ μ τ υ φ χ ψ ω俄语字符：А Б В Г Д Е Ё Ж З И Й К Л М Н О П Р С Т У Ф Х Ц Ч Ш Щ Ъ Ы ЬЭ Ю Яа б в г д е ё ж з и й к л м н о п р с т у ф х ц ч ш щ ъ ы ь э ю я汉语拼音：ā á ǎ à ō ó ǒ ò ē é ě è ī í ǐ ì ū ú ǔ ù ǖ ǘ ǚ ǜ ü ê ɑ ń ň ɡㄅㄆㄇㄈㄉㄊㄋㄌㄍㄎㄏㄐㄑㄒㄓㄔㄕㄖㄗㄘㄙㄚㄛㄜㄝㄞㄟㄠㄡㄢㄣㄤㄥㄦㄧㄨㄩ中文字符：偏旁部首：横起：夬丅乛竖起：丄丩乚撇起：夊亅亇厃々捺起：丂零壹贰叁肆伍陆柒捌玖拾佰仟万亿吉太拍艾分厘毫微卍卐卄巜弍弎弐朤氺曱甴囍兀々〆のぁ〡〢〣〤〥〦〧〨〩日语：ぁあぃいぅうぇえぉおかがきぎくぐけげこごさざしじすずせぜそぞただちぢっつづてでとどなにぬねのはばぱひびぴふぶぷへべぺほぼぽまみむめもゃやゅゆょよらりるれろゎわゐゑをん注音码：ァアィイゥウェエォオカガキギクグケゲコゴサザシジスズセゼソゾタダチヂッツヅテデトドナニヌネノハバパヒビピフブプヘベペホボポマミムメモャヤュユョヨラリルレロヮワヰヱヲンヴヵヶ绘表符号：─━│┃┄┅┆┇┈┉┊┋┌┍┎┏┐┑┒┓└┕┖┗┘┙┚┛├┝┞┟┠┡┢┣┤┥┦┧┨┩┪┫┬┭┮┯┰┱┲┳┴┵┶┷┸┹┺┻┼┽┾┿╀╁╂╃╄╅╆╇╈╉╊╋═║╒╓╔╕╖╗╘╙╚╛╜╝╞╟╠╡╢╣╤╥╦╧╨╩╪╫╬╳╔ ╗╝╚ ╬ ═ ╓ ╩ ┠ ┨┯ ┷┏ ┓┗ ┛┳⊥﹃﹄┌╭╮╯╰表情符号：*^_^* ^*^ ^-^ ^_^ ^︵^经典字符全收集：、。

计算机测量与控制．２０２０．２８（１１）　犆狅犿狆狌狋犲狉犕犲犪狊狌狉犲犿犲狀狋牔犆狅狀狋狉狅犾　·２３８　·收稿日期：２０２００４１７；　修回日期：２０２００５１５。

基金项目：国家自然科学基金（６１６７２３９６）。

作者简介：陈国良（１９７２），男，湖南湘潭人，副教授，主要从事智能控制与机器人技术、计算机视觉、机电一体化方向的研究。

文章编号：１６７１４５９８（２０２０）１１０２３８０４ ＤＯＩ：１０．１６５２６／ｊ．ｃｎｋｉ．１１－４７６２／ｔｐ．２０２０．１１．０４８ 中图分类号：ＴＰ３９文献标识码：Ａ基于犔犻狀狌狓的多核实时任务调度算法改进陈国良，朱艳军（武汉理工大学机电工程学院，武汉　４３００７０）摘要：嵌入式实时系统通常被实现为多任务系统，以满足多个外部输入的响应时间的最后期限约束；Ｌｉｎｕｘ内核中已经实现了基于ＥＤＦ（ｅａｒｌｉｅｓｔｄｅａｄｌｉｎｅｆｉｒｓｔ）调度算法的ＤＬ调度器，使得实时任务能在截止期限内运行完成；但对于多核处理器，由于实时任务在ＥＤＦ算法下会出现Ｄｈａｌｌ效应，文章对Ｌｉｎｕｘ内核中实时任务调度算法进行了改进；在ＥＤＦ算法的基础上，实现ＬＬＦ（ｌｅａｓｔｌａｘｉｔｙｆｉｒｓｔ）调度算法并对其加以改进，通过降低任务上下文切换频率以及减少松弛度的计算来减小调度过程中的颠簸现象；实验证明该方法既避免了Ｄｈａｌｌ效应，又减少了任务上下文切换带来的系统开销，并使得任务能在截止期限内完成调度，取得了较好的调度性能。

关键词：实时任务；Ｌｉｎｕｘ内核；多核处理器；ＬＬＦ犐犿狆狉狅狏犲犱犕狌犾狋犻－犮狅狉犲犚犲犪犾－狋犻犿犲犜犪狊犽犛犮犺犲犱狌犾犻狀犵犃犾犵狅狉犻狋犺犿犅犪狊犲犱狅狀犔犻狀狌狓ＣｈｅｎｇＧｕｏｌｉａｎｇ，ＺｈｕＹａｎｊｕｎ（ＳｃｈｏｏｌｏｆＭｅｃｈａｎｉｃａｌａｎｄＥｌｅｃｔｒｏｎｉｃＥｎｇｉｎｅｅｒｉｎｇ，ＷｕｈａｎＵｎｉｖｅｒｓｉｔｙｏｆＴｅｃｈｎｏｌｏｇｙ，Ｗｕｈａｎ　４３００７０，Ｃｈｉｎａ）犃犫狊狋狉犪犮狋：Ｅｍｂｅｄｄｅｄｒｅａｌ－ｔｉｍｅｓｙｓｔｅｍｓａｒｅｏｆｔｅｎｉｍｐｌｅｍｅｎｔｅｄａｓｍｕｌｔｉ－ｔａｓｋｉｎｇｓｙｓｔｅｍｓｔｏｍｅｅｔｄｅａｄｌｉｎｅｃｏｎｓｔｒａｉｎｔｓｏｎｔｈｅｒｅ ｓｐｏｎｓｅｔｉｍｅｏｆｍｕｌｔｉｐｌｅｅｘｔｅｒｎａｌｉｎｐｕｔｓ．ＴｈｅＤＬｓｃｈｅｄｕｌｅｒｂａｓｅｄｏｎｔｈｅＥＤＦ（ＥａｒｌｉｅｓｔＤｅａｄｌｉｎｅＦｉｒｓｔ）ｓｃｈｅｄｕｌｉｎｇａｌｇｏｒｉｔｈｍｈａｓｂｅｅｎｉｍｐｌｅｍｅｎｔｅｄｉｎｔｈｅＬｉｎｕｘｋｅｒｎｅｌ，ｓｏｔｈａｔｒｅａｌ－ｔｉｍｅｔａｓｋｓｃａｎｂｅｃｏｍｐｌｅｔｅｄｗｉｔｈｉｎｔｈｅｄｅａｄｌｉｎｅ．Ｂｕｔｆｏｒｍｕｌｔｉ－ｃｏｒｅｐｒｏｃｅｓｓｏｒｓ，ｒｅａｌ－ｔｉｍｅｔａｓｋｓｗｉｌｌｈａｖｅＤｈａｌｌｅｆｆｅｃｔｕｎｄｅｒｔｈｅＥＤＦａｌｇｏｒｉｔｈｍ．Ｉｎｖｉｅｗｏｆｔｈｅａｂｏｖｅｐｒｏｂｌｅｍｓ，ｔｈｉｓｐａｐｅｒｐｒｏｐｏｓｅｓａｎｉｍｐｒｏｖｅｄｍｅｔｈｏｄｆｏｒｒｅａｌ－ｔｉｍｅｔａｓｋｓｃｈｅｄｕｌｉｎｇａｌｇｏｒｉｔｈｍｓｉｎｔｈｅＬｉｎｕｘｋｅｒｎｅｌ．ＢａｓｅｄｏｎｔｈｅＥＤＦａｌｇｏｒｉｔｈｍ，ｔｈｅＬＬＦ（ＬｅａｓｔＬａｘｉｔｙＦｉｒｓｔ）ｓｃｈｅｄｕｌｉｎｇａｌｇｏｒｉｔｈｍｉｓｉｍｐｌｅｍｅｎｔｅｄａｎｄｉｍｐｒｏｖｅｄ．Ｉｔｒｅｄｕｃｅｓｔｈｅｊｉｔｔｅｒｉｎｔｈｅｓｃｈｅｄｕｌｉｎｇｐｒｏｃｅｓｓｂｙｒｅｄｕｃｉｎｇｔｈｅｔａｓｋｃｏｎｔｅｘｔｓｗｉｔｃｈｉｎｇｆｒｅｑｕｅｎ ｃｙａｎｄｒｅｄｕｃｉｎｇｔｈｅｓｌａｃｋｃａｌｃｕｌａｔｉｏｎ．ＥｘｐｅｒｉｍｅｎｔｓｓｈｏｗｔｈａｔｔｈｉｓｍｅｔｈｏｄｎｏｔｏｎｌｙａｖｏｉｄｓｔｈｅＤｈａｌｌｅｆｆｅｃｔ，ｂｕｔａｌｓｏｒｅｄｕｃｅｓｔｈｅｓｙｓｔｅｍｏｖｅｒｈｅａｄｃａｕｓｅｄｂｙｔａｓｋｃｏｎｔｅｘｔｓｗｉｔｃｈｉｎｇ，ａｎｄｅｎａｂｌｅｓｔａｓｋｓｔｏｂｅｓｃｈｅｄｕｌｅｄｗｉｔｈｉｎｄｅａｄｌｉｎｅｓ，ａｎｄａｃｈｉｅｖｅｓｂｅｔｔｅｒｓｃｈｅｄｕｌｉｎｇｐｅｒ ｆｏｒｍａｎｃｅ．犓犲狔狑狅狉犱狊：ｔａｓｋｓｃｈｅｄｕｌｉｎｇ；Ｌｉｎｕｘｋｅｒｎｅｌ；ｍｕｌｔｉ－ｃｏｒｅｐｒｏｃｅｓｓｏｒ；ＬＬＦ０　引言随着计算机的发展，实时调度被广泛应用于实时性强的众多领域，如电子商务、交通管制、航空航天等，要求操作系统能够及时高效地处理多任务的运行。

极限误差符号
极限误差符号通常用Δ表示，读作delta。

在数学中，Δ常常用来表示一个变量的增量或者减量，也就是这个变量的变化量。

例如，如果一个函数在某一点的增量是Δx，那么我们就可以说Δx是这个函数在这一点的极限误差。

此外，Δ还常常用来表示一个小的、可忽略的部分。

例如，在微积分中，Δx 就表示当x趋近于某个值时，x与这个值的差值。

由于Δx非常小，所以我们通常可以忽略它的影响，从而得到更准确的结果。

Δ是一个非常常用的数学符号，它在各种数学理论和公式中都有出现。

虽然Δ的具体含义可能会因为上下文的不同而有所不同，但是它基本上都是表示一个变量的变化量或者一个小的、可忽略的部分。

American Journal of Medical Genetics121A:258–262(2003)Clinical ReportDonnai-Barrow Syndrome:Four Additional Patients Nicolas Chassaing,1,2Didier Lacombe,2*Dominique Carles,3Patrick Calvas,1Robert Saura,2and Eric Bieth11Service de ge´ne´tique me´dicale,Hoˆpital Purpan,Toulouse,France2Service de ge´ne´tique me´dicale,CHU Pellegrin,Bordeaux,France3Laboratoire d’Anatomo-Pathologie,CHU Pellegrin,Bordeaux,FranceIn1993,Donnai and Barrow reported a new syndrome in two sets of sibs and in anunrelated child,including diaphragmatichernia,exomphalos,absent corpus callosum,hypertelorism,myopia,and sensorineuraldeafness.Since then,only four similar pa-tients have been documented.We describefour additional patients,including two sib-ling pairs from healthy parents.This reportfirmly establishes this syndrome as a distinctclinical entity and provides further evidence for its previously postulated autosomalrecessive inheritance.ß2003Wiley-Liss,Inc.KEY WORDS:Donnai-Barrow syndrome;diaphragmatic hernia;ab-sent corpus callosum;hy-pertelorism;sensorineuraldeafness;myopiaINTRODUCTIONWe report two sets of sibs(two male and two female patients)from two unrelated families with identical features to those described by Donnai and Barrow [1993].The main features are diaphragmatic hernia, exomphalos,absent corpus callosum,hypertelorism, myopia,and sensorineural deafness.Otherfindings include wide anterior fontanel,downslanting palpebral fissures,iris coloboma,short nose with a broad tip,and intestinal malrotation.Autosomal recessive inheritance was suspected because two sibling pairs of healthy parents were affected.Four patients with this condition were reported by Gripp et al.[1997]and by Avunduk et al.[2000].In two families,the parents werefirst cousins,providing more evidence for autosomal reces-sive inheritance.CLINICAL REPORTSPatient1A male fetus from a healthy unrelated couple,mother aged27and father aged29years,was delivered at 22weeks of gestation.Weight was491g(50th centile), length was29.7cm(50th centile),and occipitofrontal circumference(OFC)was21cm(50th centile).The pregnancy was terminated after ultrasound scan docu-mented agenesis of the corpus callosum and an arach-noid cyst.The facial appearance of the fetus showed a large anterior fontanel,hypertelorism,prominent eyes, marked underorbital creases,short palpebralfissures,a short nose with a broad tip,and low set and posteriorly angulated ears(Fig.1).Autopsy confirmed agenesis of the corpus callosum;no other internal abnormalities were noted.Chromosomes were normal(46,XY).Patient2A male fetus,the sib of patient1,delivered at25weeks of gestation.Weight was850g(75th centile),length was 34cm(50th centile),OFC was25cm(75th centile).The pregnancy was interrupted after ultrasound scan documented diaphragmatic hernia.The facial appear-ance was very similar to that of thefirst affected fetus with wide anterior fontanel and metopic suture,hyper-telorism,marked underorbital creases,a short nose with a broad tip,mid-face hypoplasia,and low set and normally angulated ears(Fig.2).Autopsy confirmed a left diaphragmatic hernia,and found partial agenesis of the corpus callosum and double superior vena cava. Chromosomes were normal(46,XY).Patient3A female fetus from a healthy unrelated couple, mother aged39and father aged31years,delivered at 26weeks of gestation.Weight was960g(50th centile), length was39cm(97th centile),OFC was26cm(75th*Correspondence to:Didier Lacombe,Department of Medical Genetics,CHU Pellegrin-Enfants,Place Ame´lie Raba-Le´on,F-33076Bordeaux Cedex,France.E-mail:******************************Received19November2002;Accepted26February2003DOI10.1002/ajmg.a.20266ß2003Wiley-Liss,Inc.Fig.1.Patient1.a:Note hypertelorism,marked underorbital creases,short nose with broad tip.b:Note low-set and posteriorly angulatedears. Fig.2.Patient2.a:Note hypertelorism,marked underorbital creases,short nose with broad tip,wide anterior fontanel and metopic suture and mid-face hypoplasia.b:Note low-set ears.Donnai-Barrow Syndrome259centile).The pregnancy was terminated after ultrasound scan documented diaphragmatic hernia,and hypoplasia of the corpus callosum.Autopsy confirmed a diaphrag-matic hernia.No other internal abnormalities were noted,but the brain was not examined.Chromosomes were normal (46,XX).Patient 4A girl,the sib of patient 3,was born normally after 40weeks of pregnancy.A small exomphalos was seen during pregnancy (23weeks of gestation)using ultra-sound scan.No other abnormalities were detected.Birth weight was 3.290kg (50–75th centile),height was 51cm (50th centile),and OFC was 35.5cm (50th centile).A small exomphalos was repaired at birth.Hypertelorism was also noted.Brain ultrasound findings were consis-tent with partial agenesis of the corpus callosum.Ophthalmologic examination showed severe bilateral myopia and bilateral attenuation of retinal pigment epithelium.Chromosomes were normal (46,XX).When she was 3-months old,severe bilateral sensorineural deafness was diagnosed.At the age of 18months,she was referred to the genetics clinic.She had marked hypertelorism,epi-canthal folds,downslanting palpebral fissures,low-set and posteriorly angulated ears,and a short nose with a broad tip (Fig.3).Psychomotor development was in the low range of the normal.Cranial CT scan confirmed partial agenesis of the corpus callosum.Proteinuria was detected on a routine urine investigation and was in the range of 100mg/day.Renal ultrasound showed normal kidneys.DISCUSSIONDonnai and Barrow [1993]reported two sets of sibs and an unrelated individual with a new syndrome.The phenotype associated diaphragmatic hernia,exompha-los,absent corpus callosum,intestinal malrotation,myopia,sensorineural deafness,and particular face.The facial dysmorphism included large anterior fonta-nel,hypertelorism,downslanting palpebral fissures,short nose with a broad tip,and low-set,posteriorly angulated ears.Gripp et al.[1997]and Avunduk et al.[2000]subsequently reported four additional patients with the same features.The findings in our patients are very similar to those described in this syndrome.Features of all the reported patients including ours are summarized in Table I.Pregnancy was terminated in about one half of the patients (6/13)due to ultrasound scan documentation of diaphragmatic hernia and/or agenesis of the corpus callosum.Two children died in the first day of life secondarily to the diaphragmatic hernia.The living children’s birth weight,length and OFC were high-ranking.Absence of the corpus callosum and diaphragmatic hernia are the major features of the syndrome.Exomphalos seems to be frequent,but is found in only one of our four patients.Facial dysmorph-ism is a constant and characteristic feature.Myopia,sensorineural deafness and developmental delay are reported in all living children.Patient 4has a mild developmental delay as she walked at 17months.The psychomotor retardation can be worsened by severe myopia and sensorineural hearing loss.A cardiac abnor-mality (VSD,double superior vena cava)is detected in two cases,and may sometimes be part of the syndrome.Severe epilepsy and bicornuate uterus have been de-scribed once and may be rare features of the syndrome.Syndromes with similar features (Kniest,Marshall,Stickler,De Hauwere,and Fryns syndromes)were discussed by Donnai and Barrow [1993]and were considered as distinct syndromes.Donnai and Barrow [1993]and Gripp et al.[1997]compared their patients with two sibs described by Holmes and Schepens [1972]who had severe ocular anomalies,hypertelorism,sen-sorineural deafness and umbilical hernia in one sib.They were unable to conclude whether they had the same condition.Since the initial report by Donnai and Barrow [1993],a new syndrome has been described by Temtamy etal.Fig.3.Patient 4at age 18months.a :Note hypertelorism,epicanthal folds,short nose with broad tip,downslanting palpebral fissures.b :Note low-set and posteriorly angulated ears.260Chassaing et al.[1996].They reported three sibs with an autosomal recessive syndrome consisting in absent corpus callo-sum,myopia,delayed closure of fontanel in one sib,coloboma of iris,hypertelorism,antimongoloid slanting of eyes,low-set ears,and developmental delay.This syndrome associated other features such as dilatation of the cerebral ventricles,dental and skeletal anomalies,and evidence of connective dysplasia in the form of dilatation of the aorta and aortic regurgitation,joint hyperextensibility,and ultrastructural changes in the gingiva which revealed reduced collagen.Furthermore,no affected children in that family had diaphragmatic hernia,exomphalos or sensorineural deafness,and we do not think that this is the same entity.Devriendt et al.[1998]published a patient with dia-phragmatic hernia,hypertelorism,severe myopia and sensorineural deafness,but no agenesis of the corpus callosum.In addition,proteinuria was detected,and the authors concluded that this patient presented features of Donnai-Barrow syndrome and facio-oculo-acoustico-renal (FOAR)syndrome.The FOAR syndrome includes proteinuria and some features of the Donnai-Barrow syndrome,such as high myopia,iris coloboma,sensor-ineural deafness,umbilical hernia,and facial dys-morphism with delayed closure of anterior fontanel,hypertelorism,and downslanting palpebral fissures [Schowalter et al.,1997].None of the affected children had agenesis of the corpus callosum,and except for the case reported by Devriendt et al.[1998],none had diaphragmatic hernia.One of our Donnai-Barrow pa-tients (patient 4)had proteinuria,thus providing more evidence that these two syndromes overlap.Interest-ingly,the case reported by Holmes and Schepens [1972]was considered as a possible Donnai-Barrow syndrome by Gripp et al.[1997],and is described in the review of the FOAR syndrome [Schowalter et al.,1997],thereby demonstrating the difficulty of distinguishing these two syndromes.These two distinct syndromes clearly over-lap,since some patients have features of Donnai-Barrow and FOARsyndromes and may be allelic to thesamegene.In the report of Donnai and Barrow [1993],autosomal recessive inheritance was suspected because two sets of sibs,a boy and a girl in each,were affected and the parents of another patient were probably related.The parents of the patients described by Gripp et al.[1997]and Avunduk et al.[2000]were first cousins,thus providing further evidence for autosomal recessive inheritance.We report two new pairs of sibs,thereby adding further support to the postulated autosomal recessive inheritance pattern in this syndrome.We suggest that this syndrome,which is clearly a new entity with autosomal recessive inheritance,could be called the Donnai-Barrow syndrome,as it is already known in the LDDB.REFERENCESAvunduk AM,Aslan Y,Kapicioglu Z,Elmas R.2000.High myopia,hypertelorism,iris coloboma,exomphalos,absent corpus callosum,and sensorineural deafness:Report of a case and further evidence for autosomal recessive inheritance.Acta Ophthalmol Scand 78:221–222.Devriendt K,Standaert L,Van Hole C,Devlieger H,Fryns JP.1998.Proteinuria in a patient with the diaphragmatic hernia-hypertelorism-T A B L E I .C l i n i c a l F i n d i n g s i n R e p o r t e d P a t i e n t sA v u n d u k e t a l .T o t a l%S e x M M F F M F F M F M F F M 6M /7F T h e r a p e u t i c a b o r t i o n þþþÀÀþÀþÀÀþÀÀ6/1345B i r t h w e i g h t c e n t i l e ?50–75t h 97t h ?97t h 50–75t h 50–75t h 80t h L a r g e a n t e r i o r f o n t a n e l þþ?ÀþþþþÀþþþÀ9/1275H y p e r t e l o r i s m þþ?þþþþþþþþþþ12/12100D o w n s l a n t i n g p a l p e b r a l fis s u r e s aÀÀ?þþþþ?þþÀþþ8/1173H i g h m y o p i a ???þþ?þ?þ?þ5/5100I r i s c o l o b o m a ???Àþ?À?Àþ??þ3/650S h o r t n o s e þþ?þþþþ?þþÀþÀ9/1182P o s t e r i o r l y a n g u l a t e d e a r s þÀ?þþþþ?ÀþþÀÀ7/1164S e n s o r i n e u r a l d e a f n e s s ???þþ?þ?þ???þ5/5100D i a p h r a g m a t i c h e r n i a ÀþþÀþÀþþþþþþÀ9/1370E x o m p h a l o s /c o r d h e r n i a ÀÀÀþþþþ?ÀÀþÀþ6/1250M a l r o t a t i o n o f b o w e l ÀÀÀÀþÀþÀÀþÀÀÀ3/1323A b s e n t c o r p u s c a l l o s u m þþþþþþþ?þ?þþþ11/11100D e v e l o p m e n t a l d e l a y???þþ?þ?þ????4/4100aD o w n s l a n t i n g p a l p e b r a l fis s u r e s w e r e n o t r e p o r t e d i n s o m e o f t h e p u b l i s h e d c a s e s ,a n d h a v e b e e n a d d e d t o t h e t a b l e o n t h e b a s i s o f r e p o r t e d p i c t u r e s .Donnai-Barrow Syndrome261myopia-deafness syndrome:further evidence that the facio-oculo-acous-tico-renal syndrome represents the same entity.J Med Genet35:70–71. Donnai D,Barrow M.1993.Diaphragmatic hernia,exomphalos,absent corpus callosum,hypertelorism,myopia,and sensorineural deafness:A newly recognized autosomal recessive disorder?Am J Med Genet47: 679–682.Gripp KW,Donnai D,Clericuzio CL,McDonald-McGinn DM,Guttenberg M, Zackai EH.1997.Diaphragmatic hernia-exomphalos-hypertelorism syndrome:A new case and further evidence of autosomal recessive inheritance.Am J Med Genet68:441–444.Holmes LB,Schepens CL.1972.Syndrome of ocular and facial anomalies, telecanthus,and deafness.J Pediatr81:552–555.Temtamy SA,Salam MA,Aboul-Ezz EH,Hussein HA,Helmy SA,Shalash BA.1996.New autosomal recessive multiple congenital abnormalities/ mental retardation syndrome with craniofacial dysmorphism absent corpus callosum,iris colobomas and connective tissue dysplasia.Clin Dysmorphol5:231–240.Schowalter DB,Pagon RA,Kalina RE,McDonald R.1997.Facio-oculo-acoustico-renal(FOAR)syndrome:Case report and review.Am J Med Genet69:45–49.262Chassaing et al.。