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C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | If the code is a triplet code, there are 64 (4×4×4) possible triplets. Our results suggest that it is unlikely that only 20 of these represent the 20 amino-acids and that the remaining 44 are nonsense. If this were the case, the region over which suppressors of the FC
0 family occur (perhaps a quarter of the B
cistro... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | At the recent Biochemical Congress at Moscow, the audience of Symposium I was startled by the announcement of Nirenberg that he and Matthaei18
had produced polyphenylalanine (that is, a polypeptide all the residues of which are phenylalanine) by adding polyuridylic acid (that is, an RNA the bases of which are all urac... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | , 43
, 416 (1957).
Benzer, S., Proc. U.S. Nat. Acad. Sci
., 45
, 1607 (1959), for refs. to earlier papers.
Benzer, S., Proc. U.S. Nat. Acad. Sci.,
47
, 403 (1961); see his Fig. 3.
Brenner, S., Benzer, S., and Barnett, L., Nature
, 182
, 983 (1958).
Brenner, S., Barnett, L., Crick, F. H. C., and Orgel, A., J. Mol.... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | 此外,所有被详细研究过的异常人血红蛋白都只显示出单个氨基酸的变化[4]
。这些新近的实验结果基本上排除了重叠密码存在的可能性。
英文
如果密码是不重叠的,那么必然存在某种规则以指示如何沿着连续的碱基序列选择出正确的三联体(或四联体,或其他任何可能的类型)。一种显而易见的设想是,每组第四个碱基都是一个“逗号”;另一种想法是某些三联体是“有义”的,而其他的则是“无义”的,就像克里克、格里菲思和奥格尔[5]
提出的无逗号密码那样。或者从某个固定的位点起始沿着碱基序列以每次读取三个(或四个,或任何其他可能的数量)的方式来作出正确选择,我们现在更倾向于这种可能性。
英文
实验结果
我们的遗传实验是在能侵染大肠杆菌菌株的T
4... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | 英文
除了最初的FC
0突变体外,其余所有的突变都是自发产生的。不过,我们用吖啶黄作为诱变剂得到了一组突变体(作为FC
7突变体的抑制子)。我们获得的抑制子中突变位点的分布(见图2,h
行)与自发产生的抑制子中突变位点的分布大致相似,同时所有的突变体也都是非渗漏性的r
型。我们从所有突变体中选出一(小)部分并对其进行了检测,发现在吖啶黄作用下它们的回复突变率提高了。
英文
综上所述,我们总计获得了大约80种独立的r
型突变体,它们都是FC
0的抑制子,或者是抑制子的抑制子,或者是抑制子的抑制子的抑制子。所有的突变位点都分布在基因的某个有限区域内,而且都是非渗漏性的r
型突变体。
英文
在K
菌体上生长的... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | 为了说明的方便,我们仅仅显示了一种ABC
不断重复的碱基序列(这将编码一条只由一种氨基酸组成的多肽链)。我们假设密码是三联体形式的。虚线代表假想的从序列左端开始每三个一组进行阅读的“阅读框”。
英文
现在我们肯定会提出这样的问题:为什么我们得到的抑制子的突变位点不是遍布在整个基因上?最简单的假设就是,阅读框的移动产生了一些读取时“不能被接受的”三联体密码。比如,它们可能是“无义”的,或者它们代表“链的结束”,再或者由于某些和蛋白质结构复杂性有关的原因而不能被接受。这意味着,一个抑制子,如FC
0抑制子,发生突变的位点必然位于一定的区域内,使得FC
0和它的抑制子之间的阅读框的移动不至于产生“不能被接受的”三联体。但很明... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | 然而,当这三种突变同时出现在同一个基因中时却能够部分地恢复该基因的功能,从而产生能在K
菌体上生长的假野生型噬菌体。
英文
这正是编码比率为3或3的倍数时,我们预期会出现的结果。
英文
因此我们揭示编码比率的能力有赖于如下事实:至少在我们获得的一种复合“野生型”突变体中,在多肽链中增添或缺失至少一个氨基酸不会很大程度地干扰基因产物的功能。
英文
这是一种非常幸运的情形。我们之所以能制备出这一系列的突变并研究如此大的一个基因区域,可能是因为该蛋白质的这一部分对于其功能而言是非必需的。钱普和本则尔[18]
在研究r
II
区域内的互补现象时就曾提出过这种观点。通过一种特别的检测方法(联合侵染K
菌株后再涂布到B... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | 英文
因此,除非吖啶和肼通常都缺失(或增添)偶数个碱基,否则这个证据就支持编码比率为3结论。不过,因为我们对这些诱变剂的具体作用机理还不太清楚,因此我们还不能肯定地说编码比率不是6,虽然看起来更可能是3。
英文
我们有一些初步的结果表明,其他由吖啶诱发的突变经常是通过邻近位点的抑制子回复的,但是这些结果还太粗略不适合在这里报道。图6显示了P
83突变(这一突变发生在顺反子B
的另一端,B
9a
片段内)的一些抑制子分布的初步图谱。可以看出,它们分布在比FC
0的抑制子更窄的区域内,大约占顺反子B
的1/20。正如预期的那样,双突变体WT
(2+5)呈现出r
表型。
英文
图6.P
83突变及其抑制子(... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | Haemoglobin's structure was, by this time, well established—the adult red-blood-cell protein contains two identical α polypeptide chains and two identical β chains. And amino-acid substitutions in the polypeptide chains had been shown to produce disease-causing variants. In particular, biologist Vernon M. Ingram had sh... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | Results indicate that there were three tryptophan-positive peptides in both haemoglobins as shown in Fig. 1. The tryptophan-positive peptide which migrated the fastest at p
H 6.4 towards the cathode in Hb-A vanished in Hb-I. (In our previous publication, Fig. 2, 4 tryptophan-positive peptides were shown for Hb-I; this... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | (Try)(Gly)(Lys); where Ala = alanyl, Try = tryptophy1, Gly = glycyl, and Lys = lysyl. In order to preserve tryptophan, leucine-aminopeptidase was used to hydrolyse the peptide which contained it. The NH2
-terminal residue of the pentapeptide was alany1 by the method of Sanger7
. The amino-acid sequence of the pentape... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | I thank Dr. Robert J. Hill and Dr. William Konigsberg, of the Rockefeller Institute, who provided me with the α-chain of Hb-A; they also collaborated with me on the amino-acid analyses of the pentapeptide. I also thank T. Viswanatha and Mr. H. B. Marsh for assistance.
中文
(196
, 226-227; 1961)
Makio Murayama: Nation... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | 英文
结果如图1所示,在两种血红蛋白中都发现了3条含色氨酸残基的肽段。在pH值为6.4时向负极迁移最快的含色氨酸的肽段只存在于血红蛋白A中,而在血红蛋白I中这条肽段消失了。(在我们以前发表的文章中,如图2所示,在血红蛋白I中有4条含色氨酸的肽段,现在知道这是由于样品中存在血红蛋白A的污染而造成的。)正如以前所报道的,血红蛋白I经酶解后的第23条肽段向正极的移动比正常肽段更快。血红蛋白I的第23条肽段含有色氨酸残基和一个天冬氨酸残基(后者的存在使血红蛋白I能更快地向正极迁移),而在血红蛋白A相应的肽段中并不存在这两种残基。由于血红蛋白A的α链经胰蛋白酶消化后的产物中只有一个色氨酸残基,所以这一残基一定和血红蛋白I中消失的那条肽段(图... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | 英文
(荆玉祥 翻译;袁峥 审稿)
Fossil Hand Bones from Olduvai Gorge
J. Napier
Editor's Note
Here British palaeontologist John Napier studies the mechanics of hand bones recovered from the same floor at Olduvai Gorge from which Louis Leakey had recently reported a new hominid skull. Napier analyses the capacity of the fossil han... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | Fig. 1. Hand bone assemblage (drawings by Audrey Besterman). Top row. Juvenile. L. to R., terminal phalanx (thumb); 2 terminal phalanges (fingers). Second row. Juvenile. Middle phalanges, II-V. Third row. L. to R., proximal phalanx (adult), lateral and A.-P. views. 2 proximal phalanges (juvenile). Fourth row. Indetermi... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | . This is due largely to the absence in the fossil bones of any features peculiarly characteristic of brachiators. The adult gorilla hand has a number of specializations that are presumably related to its secondarily terrestrial mode of life and its great body-weight; these features, again, are absent from the fossil b... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | . The power grip is used by man when a secure and strong grip is required for performing an activity in which the elements of delicacy and precision are of secondary importance. In the power grip the object is held as in a clamp between the flexed fingers and the palm, reinforcement and counter-pressure being supported... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | , pulp-to-pulp contact cannot be made owing to the marked disproportion of the length of fingers and thumb. It would seem, therefore, that the Olduvai hand was capable of power grip equal in performance, but, in view of the evidence of the attachment of the flexor tendons, comparatively greater in strength than in mode... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | If, on the other hand, one bears the possibility in mind that some other, more advanced form was the toolmaker and the known incumbents of the floor were its victims, then it is in the functional morphology of the hand itself that one must look for evidence of toolmaking. On anatomical grounds there is no doubt that th... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | 它们强烈弯曲,掌型,骨末端一半处有很清晰的槽,以便指浅屈肌附着。
英文
图1.手骨组合(奥德丽·贝斯特曼绘画)。最上面一排:未成年个体,从左到右,远节指骨(拇指)、两块远节指骨(手指);第2排:未成年个体,中节指骨,II~V;第3排:从左到右,近节指骨(成年个体),侧面与掌侧视图、两块近节指骨(未成年个体)。第4排:年龄未确定,从左到右,大多角骨、手舟骨和头状骨。
英文
成年个体的近节指骨(图1,第3排)与现代人类的同等长度的骨相比也粗壮很多;纵横两个方向都强烈弯曲,呈纺锤形,掌面深陷;纤维状屈肌腱鞘脊非常明显,从骨基部延伸到颈部。
英文
未成年个体的远节指骨(图1,第1排)的骨骺融合不完全,形状上有智人的特征,... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | 如果假设发现在生活面上的早期奥杜威文化的器物是由在此发现遗骸的物种所创造的,那么,这个判断标准是成立的;此外,可能会得出一个有趣的结论:在人类演化的谱系上制作工具的出现远远早于现代人手雏形的出现。
英文
从另一方面说,如果有人认为某些更高等的物种才是工具制造者,而在生活面上发现的动物只是其牺牲品,那么就必须从手的功能形态学上寻找手本身制造工具的证据。就解剖学而言,在基本的有力抓握与精确抓握方面,奥杜威手骨无疑十分高级,能够利用现成的物体作为工具来获取利益。不太确定是否能制造工具,因为这不仅涉及外部环境因素,还涉及奥克利一直坚持的大脑的智力因素[2]
。地层中第I层的未成年个体头骨破片的报道即将发表,通过指出未成年个体头骨的近... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | 212 is a source of comparatively small flux density and although the diffraction effects at the Moon's limb were clearly visible the signal-to-noise ratio was inadequate to study the pattern in detail and hence to realize the full potentialities of the method. Here we describe the observation of a series of occultation... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | 273 is a double source orientated in such a way that whereas the two components passed successively behind the Moon at both immersions, they reappeared almost simultaneously. The prominent diffraction fringes show that the angular sizes of these components must be considerably smaller than 10′′, which is the order of s... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | It has been shown by Scheuer4
that it is possible to recover the true brightness distribution across the source from the observed diffraction pattern, the resolution being subject only to limitations imposed by the receiver bandwidth and the finite signal to noise ratio and being independent of the angular scale of th... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | was assumed to be 3′′ as indicated by the estimates at position angles 105° and 83°. The individual measurements at each frequency are reasonably consistent but there is a striking variation of the angular size of component A
with frequency and evidence of a similar variation for component B
. As at the time of the A... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | , where most of the emission arises in a source about 0.5′′ wide, is markedly flatter than that of A
, where it arises in a source about 2′′ wide.
中文
The analysis is not sufficiently accurate to reach any reliable conclusions on the ellipticity of the individual components of 3C
273, but allowing for the uncertain... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | , that the size of the triangles defined by the Moon's limb was larger than would be expected from the estimated timing errors. This suggests that errors in the positions of the Moon's limb are more important than the estimated timing errors, and possibly that the effective position of the source varies slightly with f... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | respectively, and allows a new limit to be set to the density of the lunar ionosphere. Thus, from his observations at 81.5 Mc/s, Elsmore has set an upper limit to the electron density of 103
cm–3
; and it follows that the present measurements set a limit of about 102
cm–3
. Similarly, Buckingham7
has estimated tha... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | Bolton, J. G., Gardner, F. F., and Mackey, M. B. (unpublished results).
Scheuer, P. A. G., Austral. J. Phys.
, 15
, 333 (1962).
Slee, O. B., Mon. Not. Roy. Astro. Soc.
, 123
, 223 (1961).
Elsmore, B., Phil. Mag.
, 2
, 1040 (1957).
Buckingham, M. J., Nature
, 193
, 538 (1962).
Blackwell, D. E., and Ingham, M. F.... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | 假设当频率为410兆周/秒和1,420兆周/秒时,3C
273的流量密度[3]
分别是60瓦·米–2
(周/秒)–1
和35瓦·米–2
(周/秒)–1
,并且在此频率范围内,每个子源的频谱可由S
∝f
n
表示,则上述比值相应于子源A
和B
的谱指数分别为–0.9和0.0。A
的谱指数是II类射电源的典型值,但B
的平谱是最特别的,目前尚未发表过类似的频谱的测量结果。如果假定谱指数在频率降至136兆周/秒时仍为常数,则在此频率下子源A
几乎贡献总发射的90%,通过比较8月5日当频率为136兆周/秒和410兆周/秒时的掩始时间可以证实这一结论。
英文
朔伊尔[4]
曾指出,可以通过观测到的衍射图案来重... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | 这表明月球边缘的位置误差比估算的时间误差更重要,并且源的有效位置可能随频率稍有变化。因此,每个源的位置可能是由在相关时间内月球边缘所确定的三角形中内切圆的中心所给出的。航海天文历编制局的尼克尔森博士已做过计算,估算的位置如下:
英文
表2.3C
273两个子源的观测掩源的时间
子源A
(世界时)
子源B
(世界时)
消失的时间
1962年8月5日
07h 46m 00s ±1s
07h 46m 27.2s ± 0.5s
重现的时间
1962年8月5日
09h 05m 45.5s ±1s
09h 05m 45.7s ± 1.5s
消失的时间
1962年10月26日
02h 55m 09.0s ±1s
02h 56... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | HE only objects seen on a 200-in. plate near the positions of the components of the radio source 3C
273 reported by Hazard, Mackey and Shimmins in the preceding article are a star of about thirteenth magnitude and a faint wisp or jet. The jet has a width of 1′′-2′′ and extends away from the star in position angle 43°.... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | for the three very wide emission bands.
中文
Table1. Wave-lengths and identifications
中文
It thus appears that six emission bands with widths around 50Å can be explained with a red-shift of 0.158. The differences between the observed and the expected wave-lengths amount to 6Å at the most and can be entirely underst... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | Only the detection of an irrefutable proper motion or parallax would definitively establish 3C
273 as an object within our Galaxy. At the present time, however, the explanation in terms of an extragalactic origin seems most direct and least objectionable.
中文
I thank Dr. T.A. Matthews, who directed my attention to t... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | 这个核心区域在光学上比迄今为止所有通过射电源证认的亮星系的亮度还要大100倍。如果射电源的光学喷流和子源A
与星系相关,那么它们的距离应为50千秒差距,这意味着其时间尺度超过105
年。在光度恒定的情况下,其光学波段内辐射的总能量量级应为1059
尔格。
英文
只有确定无误地检测到其自行或视差才能最终肯定3C
273为银河系中的天体。然而,目前来看,将其视为起源于河外的天体似乎是最直接、最不会引起争议的。
英文
非常感谢马修斯博士将我的注意力引向射电源,并感谢格林斯坦博士和奥凯博士与我进行了有益的讨论。
英文
Molecular Biology, Eugenics and Euphenics
*
J. L... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | Recent years have seen breath-taking advances in the molecular foundations of biology, at a pace that reminds us that the gross effort in science in one year now matches the total accumulation to the beginning of this century; as much scientific effort has been invested since 1950 as was in all previous history. These ... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | Eugenic progress creeps within the joint constraints of our limited knowledge of human genetics and customary wisdom concerning its implementation. Even so, the eugenicists argue, some beginning must be made, to offset exigent counter-eugenic influences, perhaps to assure that some eugenic wisdom survives until the spe... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | Until now, the major problems of human development—not only embryology, but also the phenomena of learning (in its neurobiological aspects), immunity (with its bearing on transplantation), neoplasia and senescence—could be approached at only the most superficial level. They are about to be transformed in the sense that... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | , the abolition of immunity to transplants introduced in early life, which has clarified the biology of immunity and points to the solution of the transplantation problem. At present, human individuality is the bar to spare-part medicine: the organism rejects grafts from other individuals even of the same species, the ... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | Many social problems arise from technological imbalance, or at least have possible technological antidotes which can then be properly discussed here. For example, the political stability of the world might be enhanced if the present technology of the detection matched that of the power output of nuclear explosives; lik... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | for the succession the military uses of industrial technology.
中文
Man's control of his own development, “euphenics”, transmutes the means, and also the ends of eugenics, as have all the precedent cultural revolutions that have shaped the species: language, agriculture, political organization, the physical technologi... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | In our inquiry on his future, the aims of human existence are inseparable from the power and responsibility for human nature. It becomes more perplexing as biological technology dissolves the barriers around individual man and intrudes on his secret, germinal continuity. The humanist premise of individual value must fa... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | 这些研究进展的细节可以从其他渠道获知。此处值得一提的是解决遗传学基本问题的研究发现:DNA结构中遗传信息的编码机制和核苷酸序列复制的酶学机制。以上研究进展揭示了陆上生物在生物化学水平上统一的遗传模式,以及遗传信息翻译成为生物性状的过程,也就是细胞内蛋白质合成的机制。
英文
对人类的遗传质量进行有意改良的优生学,已经受到许多唯心主义者的关注。像其他崇高的目标一样,优生学曾被误认为是不人道的做法,也无法通过合乎伦理的方法来评定它的有效性和可行性。赫胥黎和马勒巧妙地引用一个优生学的例子深刻驳斥了这种自满情绪:人类从长期史前进化中获得的生物学遗产很幸运地刚好能满足现代人的体能需求以及适应现代社会技术的复杂性。简单来说,如果人类长得像“... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | 英文
许多社会问题是由技术不均衡引起的,尽管有少数通过技术恢复均衡的方法,随后我们会对后者进行适当的讨论。例如,如果现有的核探测技术与核爆炸技术相匹配,那么世界政治将更加稳定;同样的平衡也存在于人类适度的多育与婴儿的死亡率之间。以目前的情况看,同种移植技术已经达到初步阶段,如果在此基础上继续发展的话,那么由人类器官紧缺所引起的巨大压力将得到改善。其中一个可能的优生学方案是将其他物种作为器官来源。如果这些器官的来源在遗传上是一致的,并且能通过免疫和功能适应性的特定筛选,那么从其他物种进行异种移植这个较为困难的问题就能得以缓解了。目前,动物中只有近交系小鼠符合这些标准。通过工业生产特异蛋白质(化学合成或细胞合成)将是一个非常重要的辅助... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | The idea that the continents drift slowly over the surface of the Earth was first put forward by the German Geophysicist Alfred Wegener early in the twentieth century, but scientific opinion that Wegener's hypothesis might be correct swung in that direction only after the Second World War. One of the decisive pieces of... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | The general increase in wave-length of the anomalies away from the crest of the ridge is almost certainly associated with the increase in depth to the magnetic crustal material1
. Local anomalies of short-period may often be correlated with bathymetry, and explained in terms of reasonable susceptibility contrasts and ... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | In this low magnetic latitude (inclination–6°) the effect of a body magnetized in the present direction of the Earth's field is to reduce the strength of the field above it, producing a negative anomaly over the body and a slight positive anomaly to the north. Here, over the centre of the Ridge, the bottom topography i... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | control of contouring is less precise. The other example is central where the control is good. In both cases the intensity of magnetization deduced was about 0.005 e.m.u.; this is equivalent to an effective susceptibility of ±0.0133: (effective susceptibility=total intensity of magnetization (remanent+induced)/present ... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | , normally magnetized; diagonally shaded blocks, reversely magnetized. Effective susceptibility of blocks, 0.0027, except for the block under the median valley in profiles 2 and 3, 0.0053 (1) Pacific Grain. Total field strength, T
=0.5 oersted; inclination, I
=60°; magnetic bearing of profile, θ
=073°. (2) Mid-Atlan... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | , but the most plausible of the models used involved very severe restrictions on the distribution of lava flows in crustal layer 2. They are readily explained in terms of reversals assuming the model shown in Fig. 4 (1). It can be shown that this type of anomaly pattern will be produced for virtually all orientations a... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | . Since the only reasonable explanation of the magnetic anomalies mapped near the site of the drilling is that the area is underlain by a block of normally magnetized crustal material14
, it appears that the drill penetrated a layer of reversely magnetized lava overlying a normally magnetized block.
中文
In Fig. 4 it... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | In order to explain the steep gradients and large amplitudes of magnetic anomalies observed over oceanic ridges all authors have been compelled to assume vertical boundaries and high-susceptibility contrasts between adjacent crustal blocks. It is appreciated that magnetic contrasts within the oceanic crust can be expla... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | Dietz, R. S., Nature
, 190
, 854 (1961).
Cox, A., Doell, R. R., and Dalrymple, G. B., Nature
, 198
, 1049 (1963).
Mason, R. G., Geophys. J.
, 1
, 320 (1958).
Mason, R. G., and Raff, A. D., Bull. Geol. Soc. Amer.
, 72
, 1259 (1961).
Hospers, J., Geol. Mag.
, 91
, 352 (1954).
Thorarinsson, S., Einarsson, T., an... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | 图2显示了球极投影上的矢量方向。计算机先对磁矢量进行“最佳拟合”并假定这个拟合结果成立,然后对地块上的异常重新进行运算,便可以得出一个拟合后的精确表示。这种拟合适用于受到反向磁化作用时的情况,但并不适用于受到近似正向磁化作用时的情况。存在这种差异并不奇怪,因为我们忽略了相邻地形的影响以及附近其他磁异常的干扰。此外,这个正向磁化作用的例子靠近区域的转角处,其边界的控制不够精确。另一个例子处于约束得较好的中心位置。在这两种情况下,推算出的磁化强度均约为0.005个电磁单位,由此可以得出有效磁化率为±0.0133:(有效磁化率=总磁化强度(剩余的+感应的)/当前总磁场强度:相当于0.01数量级玄武岩的平均值)。
英文
图2.在球极投... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | 我们认为,莫霍钻探[13,14]
的初步结果为这个构想提供了有力的证明。钻头进入钻井底部玄武岩熔岩流40英尺处,已证明这里受到了反向磁化作用[13]
。地图上钻井附近出现了磁化异常,对此唯一合理的解释就是因为这个区域上方覆盖着一块被正向磁化的地壳物质[14]
,这表明钻头进入的被反向磁化的熔岩层下方是一块被正向磁化的岩体。
英文
我们还应注意到,图4中假设的有效磁化率与根据研究区中这些独立的特征导出的有效磁化率相比要小2倍到5倍。尽管这种导出的强度并无太大意义,但这个现象仍可表明,与主要地壳层中的侵入岩相比,岩体表面的细纹状喷出岩体(玄武岩)受到了强度更高的磁化作用。我们认为这两类岩石具有相似的化学成分(即辉长岩),并且... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | HE recent discoveries of fossil hominid remains at Olduvai Gorge have strengthened the conclusions—which each of us had reached independently through our respective investigations—that the fossil hominid remains found in 1960 at site F.L.K.N.N.
I, Olduvai, did not represent a creature belonging to the sub-family Austr... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | We have come to the conclusion that, apart from Australopithecus
(Zinjanthropus
), the specimens we are dealing with from Bed I and the lower part of Bed II at Olduvai represent a single species of the genus Homo
and not an australopithecine. The species is, moreover, clearly distinct from the previously recognized ... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | ); the supra-orbital region of the frontal bone is very variable, ranging from a massive and very salient supra-orbital torus to a complete lack of any supra-orbital projection and a smooth brow region; the facial skeleton varies from moderately prognathous to orthognathous, but it is not concave (or dished) as is comm... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | A mean cranial capacity greater than that of members of the genus Australopithecus
, but smaller than that of Homo erectus
; muscular ridges on the cranium ranging from slight to strongly marked; chin region retreating, with slight or no development of the mental trigone; maxillae and mandibles smaller than those of ... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | , in the strength of fibro-tendinous markings, in the orientation of trapezium in the carpus, in the form of the scaphoid and in the marked depth of the carpal tunnel; however, the hand bones resemble those of Homo sapiens sapiens
in the presence of broad, stout, terminal phalanges on fingers and thumb, in the form of... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | I, Olduvai, Bed I (the site that yielded also the Australopithecus
(Zinjanthropus
) skull). This is catalogued as Olduvai Hominid 6. It is possible that the tibia and fibula found at this site belong with Homo habilis
rather than with Australopithecus
(Zinjanthropus
). These limb bones have been reported on by Dr.... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | , the latter in process of erupting; the corresponding left maxillary fragment with M
1
to M
3
, the latter likewise erupting, the isolated left P
3
; parts of the vault of a small, adult cranium, comprising much of the occipital, including part of the posterior margin of foramen magnum
, parts of both parietals, r... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | . The form of the parietal—anteroposteriorly elongated and bilaterally narrow, with a fairly abrupt lateral descent in the plane of the parietal boss—reproduces closely these features in the somewhat larger parietal of the type specimen (Olduvai Hominid 7 from F.L.K.N.N.
I).
中文
(b
) Olduvai Hominid
6 from
F.L.K.... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | . The width of the mandible is 19.2 m level with the mesial half of the molar, but the maximum width must have been somewhat greater, The molar is 15.1 mm in mesiodistal length and 13.0 mm in buccolingual breadth; it is thus a small and narrow tooth by australopithecine standards, but large in comparison with Homo erec... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | . The Kanam mandibular fragment, discovered by the expedition in 1932 by one of us (L. S. B. L.), and which has been shown to possess archaic features (Tobias, Nature
, 185
, 946; 1960), may well justify further investigation along these lines. The Lake Chad craniofacial fragment, provisionally described by M. Yves C... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | have been found. It seems that the early hominids of this period were capable of making rough shelters or windbreaks and it is likely that Homo habilis
may have been responsible.
中文
Relationship to Australopithecus
(Zinjanthropus
)
The fossil human remains representing the new species Homo habilis
have been foun... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | 英文
当我们有了这一新发现时(正如路易斯·利基及其夫人玛丽·利基在先前文章中所描述的),就准备发表关于这一结论的证据,并且给予这个属于人属的新标本一个科学的名字。
英文
这些发现的检验结果使我们拓宽了判断新种的基础,并充分证实了人属存在于奥杜威地层序列的下部,比确定属于南方古猿亚科的东非人头骨或者更早、或者同时代、或者更晚。
英文
为了描述方便,本文中我们采用了威尔弗里德·勒格罗–克拉克爵士在《人类进化的化石证据》(第110页,1955年)一书中提出的对于人科的判断标准。在这个科中我们暂时接受南方古猿属和人属,包括南方古猿属目前具有的三个亚属(南方古猿亚属、傍人亚属和东非人亚属)。尽管我们中的路易斯·利基准备接受亚属的... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | 平均颅容量比南方古猿属成员的颅容量大,但是比直立人的要小一些;颅部肌肉附着处粗壮程度表现不一,在微小到非常明显的范围之间;下巴后缩,颏三角轻度发育或未形成;上颌骨和下颌骨比南方古猿的小,处于直立人和智人的范围之中;就齿系特点来说,门齿比南方古猿和直立人的相对要大;犬齿相对于前臼齿成比例增大;前臼齿比南方古猿的狭小(颊舌径),但是仍处于直立人的范围之内;臼齿的绝对尺寸处于南方古猿范围下限与直立人范围上限之间;所有牙齿都具有颊舌向变窄和近中远中径向延长的显著趋势,这一趋势在下前臼齿和下臼齿尤其明显(在下前臼齿跟座显著延长,在下臼齿远侧齿尖重新排列);顶骨矢状曲度呈现从轻微(在人亚科的变化范围之内)到中等(在南方古猿亚科的范围之内)的变化... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | 一方面,几乎所有牙齿的尺寸都能够纳入人亚科化石的变化范围之内。奥杜威第13号人科化石的牙齿表现出近中远中向延长和颊舌向缩小的特点。在有些牙齿中,齿冠指数(长/宽)甚至超过了奥杜威7号正型标本和6号副型标本。枕骨矢状曲度轻微,枕骨矢状指数处于南方古猿亚科和北京直立人的变化范围之外、智人变化范围之内。另一方面,顶骨矢状曲度要比所有南方古猿亚科标本(除一例以外)和所有北京直立人标本的都要大,指数下降到现代人群变化范围的上限。顶骨和枕骨尺寸很小,某些尺寸小于一两例南方古猿亚科标本,且所有尺寸达不到北京直立人的变化范围。顶骨前后延长、两侧变窄,顶骨凸面陡然侧斜——顶骨的形态再次展现了与正型标本(从奥杜威F.L.K.N.N.
I点发现的第7个... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | 英文
最近在D.K.
I地点第I层的下部生活层发现了由石头松散堆成的类似圆圈形状,这是值得我们注意的。在地质学上这个点和M.K.
I地点是同一时代,就在距离它不及1英里的地方发现了能人的遗骸。看来,这一时期的早期人科具有制造粗制的掩蔽物或防风墙的能力,而这一人类很可能是能人。
英文
与南方古猿(东非人)的关系
在第I层和第II层的中、下部发现了代表新种能人的人类化石,M.K.
I和F.L.K.N.N.
I两个地点的地质学年代要比出土南方古猿亚科东非人头骨的更远。其中F.L.K.
I地点出土了南方古猿(东非人)和能人的遗骸,而另外两个地点——M.N.K.
II和F.L.K.
II马伊科河年代稍近。路易斯·利基博士... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | with which numerous other haemoglobins observed in West Africa, or in persons of West African origin, are identical3
; (2) haemoglobin GChinese
, which has only been found in persons of Chinese extraction4
; (3) a haemoglobin found in a British family, haemoglobin GNorfolk
5
. There is one other haemoglobin named G... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | , was missing and another new peptide was seen instead which had moved nearer towards the cathode (Fig. 1). The new peptide gave a positive colour reaction for histidine11
, as does the βTp
IX of haemoglobin A (βA
Tp
IX). This peptide contains in haemoglobin A 16 amino-acid residues12,13
(Table 1).
中文
Table 1. A... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | 中文
To investigate this possibility, both peptides βTp
IX were eluted with 10 percent (v/v) pyridine to prevent hydrolysis of asparaginyl, and then digested with pronase for 4 h using the same arrangement as had been used for trypsin, and the resulting smaller peptides and amino-acids were separated by high voltage el... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | This peptide was not found in βG
Tp
IX. However, free asparagine could be demonstrated in the neutral band before hydrolysis. No free asparagine was found in the neutral band of βA
Tp
IX. From this it could be concluded that the residue next to leucyl in position 79 of the βG
-chain was asparaginyl and haemoglobin G... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | The red cell fragility showed an almost normal distribution: initial haemolysis at 0.5 percent sodium chloride, 50 percent haemolysis at 0.415 and 90 percent haemolysis at 0.3 percent sodium chloride. The only unusual feature was that 10 percent of the cells were still not haemolysed at 0.3 percent sodium chloride, and... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | . From iron incorporation studies in anaemic sickle-cell trait (A + S) carriers they concluded that, in the case of haemoglobin A + S at least, cells with a wide range of A : S proportions are produced—some with A < S and some with A > S. The first are rapidly eliminated and as a result the final over-all proportion of... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | . (2) Harmful in homozygotes, harmless in heterzygotes (abnormal variant < 50 > 20 percent). Haemoglobins S, C, D and E would belong to this group. (3) Harmful in heterozygotes (abnormal variant < 20 percent). To this would belong the haemoglobins which are associated with haemolysis even in the heterozygote, such as h... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | 人们注意到6号肽段(根据旧的计数系统)或胰蛋白酶消化肽段βTp
IX(根据新的命名法则)[10]
消失了,而在更接近阴极的地方出现了另一个新的肽段(图1)。这个新肽段与组氨酸可以发生阳性的颜色反应[11]
,如同血红蛋白A的βTp
IX(βA
Tp
IX)一样。在血红蛋白A中,该肽段有16个氨基酸残基[12,13]
(表1)。
英文
表1.血红蛋白A的β链胰蛋白酶消化的肽段IX的氨基酸序列
英文
图1.血红蛋白G阿克拉
胰蛋白酶消化物的指纹图谱。右侧箭头指出了βA
Tp
IX缺失的区域,左侧箭头指出了新出现的肽段βG
Tp
IX。+表示加样点。
英文
两个肽段的氨基末端[14]
都是缬氨酰,... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | 英文
他的血液化验值如下:
血红蛋白
12.6克/100毫升
红细胞
4,500,000/毫米3
红细胞压积
40%
英文
平均红细胞体积如下:
细胞体积
89 微米3
血红蛋白
28 γγ
血红蛋白浓度
32%
英文
图2.血红蛋白G纯合子染色后血液涂片。细胞被充分染色,图中没有靶细胞以及其他与血红蛋白S、C、D和E纯合子血象相关联的异常形式。
英文
红细胞的脆性实验显示出几乎正常的分布:在0.5%的氯化钠溶液中红细胞开始溶解,在0.415%的氯化钠溶液中有50%红细胞溶解,在0.3%的氯化钠溶液中有90%的红细胞溶解。唯一不正常的是在0.3%的氯化钠中仍有10%的红细胞没有溶解,只有在蒸馏水... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | from Bed I at Olduvai looked much more like Australopithecus africanus
than Homo
—and that the stratigraphically later finds from Bed II might be better subsumed within Homo erectus
. The problem of inadequate definition has dogged the study of Homo habilis
to this day. The material Leakey assigned to this species ... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | depends in part on the validity of the new species proposed for it. The new species is defined briefly as though proof had previously been presented that it is a new taxon—but in fact there is no discussion of “evidence” which clearly establishes that this is the case. The definition does include a few very broad diagn... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | has not been established either. (In this general connexion see also the recent comment by Oakley and Campbell2
.)
中文
Validity of the Proposed New Species
Although the authors do not present evidence in support of the few suggested differentially diagnostic features separating the proposed new species from the aust... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | and not far outside that for Pekin Man. The fit is slightly less close with Australopithecus
; but the sample for this form is made up of only four specimens representing three individuals. The highest value listed for Paranthropus
belongs to a tooth which had not yet begun to erupt and the final dimensions would pos... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | —indeed, the “mean” index for the sample of 13 specimens for the latter tooth is 116.3. The ranges for this index for M
2
and M
3
of Australopithecus
are 98.0-11.3 and 100.0-116.0 (N
= 10) respectively.
中文
The size can best be compared by using the module so that single values can be compared instead of pairs. T... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | . It is not possible to distinguish taxonomically between these groups by means of this index if anything like adequate sample sizes are used. As may be seen from Table 1 the means for Paranthropus
and Pekin Man are 85.2 and 86.3 respectively for P
3
and (not shown in Table 1) values for samples of modern Bantu and a... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | ” as an apparent primitive tool-maker, were culturally advanced and therefore one might expect that the moulding of the hand under the influence of manipulative activity of the human sort was not far advanced. Thus one might expect the foot to have had a more modern-looking structure than the hand in both the australop... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | ” mandible is damaged near the symphyseal region so that the partial right side has been displaced toward the left. However, the midline can be determined within very narrow limits and the internal contour of the left half is intact and undisturbed from very near the symphysis to a point behind M
2
. It is therefore s... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | . The latter is characterized among other things, as witnessed by the South African, East African and Indonesian evidence, by a small canine as compared with the size of the premolars, especially in the mandible. Indeed, the lower canines of this form are so small that they fall within the observed size range for moder... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | However, the Bed I and II groups of specimens occurred in the same geographical area, both appear to have been tool-makers and there seems no obvious morphological reasons why the earlier group could not have been ancestral to the later group. Furthermore, it seems unlikely in terms of ecology and behaviour that two mo... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | just at that stage where the essentially tool-using stage of the former was giving way to the primarily tool-making condition of the latter. The widely held belief of recent years that Paranthropus
at Olduvai was responsible for the stone implements found associated with it never did seem probable to me7
in the light... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | (as distinct from Paranthropus
). This genus would then include the whole sequence from the point where a shift to an omnivorous diet (by the inclusion of a substantial degree of carnivorousness) caused a new set of selection pressures to come into play favouring the whole complex of culture as a means of adaptation a... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | included in a single genus and the two species defined in terms of two major stages of cultural development.
中文
(205
, 121-124; 1965)
J. T. Robinson: Departments of Anthropology and Zoology, University of Wisconsin, Madison 6, Wisconsin.
References:
Leakey, L. S. B., Tobias, P. V., and Napier, J. R., Nature
, 20... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | 同样有意思的是我们注意到作者认为,如果在此情况下确定了其同种性,那么十多年前描述的材料应该归属于他们的新种而非其他情形——遵照《国际动物命名法规》的要求。
英文
因而可能得出下列结论:(a
)作者没有证明他们提出的新种确实是全新的;(b
)连作者他们自己都怀疑它是否是全新的;(c
)既然新种的有效性还不确定,人属新定义的有效性也就尚未确定。(有关这方面还可以参见奥克利与坎贝尔[2]
的最近评论。)
英文
建立新种的有效性
尽管作者没有给出证据来支持他们所提出的少量能区分新种与南方古猿亚科的不同的鉴别特征,但是这些特征的有效性仍值得探究。
英文
很显然,给作者留下深刻印象的一个特征[1,3]
是“所有牙齿都... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | 正如从表1所示,傍人与北京人的第三下前臼齿的平均值分别是85.2与86.3,现代班图人与澳大利亚土著居民样本的值(表1中没有列出)与北京人只相差一个单位的十分之几。可见,涵盖如此大范围的人科种群的系数平均值十分接近。另一方面,现代人类不同地区种群的系数平均值实际上表现出比前述更大的变化。也就是说,现代人类种内平均值的差异实际上比南方古猿、傍人以及直立人三个种群平均值的属间差异大。而且,与任何一个种群内观测到的变化幅度相比,平均值间的差异是很小的。
英文
根据可用的少量间接证据[8,1]
,“能人”的颅容量似乎与南方古猿的颅容量差异很小,其范围与后者有很大重叠。
英文
这种新型人科的足具有类似人属的结构,进化程度颇高,然... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | 英文
根据可用的证据,似乎更有理由把第I层的标本组与南方古猿联系起来,把地层II的标本组与直立人联系起来,而不是把第I层与第II层两组互相联系起来。因此采用以下做法似乎是完全合理的:把第I层的材料作为南方古猿非洲种的高等代表,第II层的组作为直立人稍微早期的成员。
英文
然而,第I层与第II层的两组标本出现在相同的地理区域,两者似乎都已经能够制造工具,而且似乎没有明显的形态学的原因能够解释为什么较早的类型不能是其后类型的祖先。而且,形态学上相似的两个类型至少都通过文化群落进行了很大程度的适应性改变,根据生态学与行为学,它们似乎不可能会在同一个普通地理区域发展。事实上很明显地,在这个区域同时存在至少两种人科类型:即所讨论的材料... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | 英文
(田晓阳 张立召 翻译;赵凌霞 审稿)
Dimensions and Probability of Life
H. F. Blum
Editor's Note
Harold Blum, a biologist at Princeton University, was unusual in being prepared to bring general thermodynamic considerations to bear on the seemingly intractable question of how life began. Erwin Schrödinger had already pointed out ... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | If one were to think of the biosphere as an open system continuously replicated in exact quantity and pattern—the same total amount of information being maintained—one would assume that no over-all change in order occurred in this system, the only change in entropy being in the Sun-Earth system. But evolution of the bi... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | indicates the logarithm to the base 2; b
is the number of questions answered; and b
2
>b
1
. The number of answers is not concerned with meaningful content—it is not a measure of the knowledge gained from the computer operation. In such an operation interest is usually focused on only the accepted answers, the rejec... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | , if we could measure these in the same dimensions. But more quantitative comparison would demand that it be possible to measure q
as an N
times a k, and this presents difficulties that appear insurmountable since we lack a co-ordinate frame of reference3
. The evolutionary record retains, for the most part, only ev... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | dimensions. We lack knowledge of any close quantitative relationship between order and meaningful content in the evolutionary changes going on in the biosphere, so in estimating change in number of facets we must rely on subjective judgment based on what seems to us to be the meaningful content. This is done whenever n... | 400套付费套装书 |
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