结果表明，三交种株高、叶绿素含量、穗长等性状与单交种的变异系数差异不显著，但群体抽穗历期延长；
The variation coefficient of TCH was similar to CKs in plant height, chlorophyll content, panicle length, and so on. The heading duration of TCH population was longer than those of CKs.
即使在感染你的时候，感冒病毒也会发生变异，而且新的病毒毒株经常出现，以至于当制药商研制出针对其中一种变异的疫苗时，血清已经过时了。
Colds mutate even while they're infecting you, and new strains pop up so often that by the time drug-makers create a vaccine against one variation, the serum is already out of date.
而那种蛋白质是病毒变化最快的部分，因此，针对一种病毒株的抗体可能识别不出另一种病毒株。
But that protein is the fastest-changing part of the virus, so antibodies to one strain might not recognize another.
但树和灌木就是很难区分的，因为没有一种方法来区分一棵树和一株灌木，其中一种不知不觉地渐变为另一种。
But tree and bush are hardly that, since there is no way to define a tree versus a bush. The two categories grade insensibly into one another.
如果我们能研制一种对所有流感病毒株都有效的疫苗，我们就可以预防年度季节性流感及偶见的流感大流行，就像其它那些疾病一样。
If only we could develop a vaccine that was effective against all strains of flu, we might prevent both annual epidemics and occasional pandemics like the one now under way.
今天，我们知道一种具有大流行强大潜力的病毒，即H1N1病毒的新毒株，从世界上另一边的另一个来源产生。
Today, we know that a virus with great pandemic potential, the new strain of the H1N1 virus, has emerged from another source on another side of the world.
经过一段时间，形成一种混合物，它包含实验室毒株的内部成分以及大流行毒株的外部成分。
After a while, a hybrid is formed which contains the inner components of the laboratory strain, and the outer components of the pandemic strain.
但是自然选择是一种强大的力量，而如果疾病的传播意味着这些药物将被广泛使用的话，一种具有抗药性的病毒毒株可能将轻易地进化出来。
But natural selection is a powerful force, and if the spread of the disease means they have to be used widely, a resistant strain of the virus could easily evolve.
2001年，乔治·布什颁发命令，禁止联邦资金支持新胚胎干细胞株的研究，这实际上是一种妥协，意味着科学家们只能对业已产生的胚胎干细胞进行研究。
In 2001 George Bush issued a ban on federal funding of research on new embryonic stem-cell lines-a compromise that meant that scientists could only work with cells from the batches they already had.
在1997年以前，西尼罗河病毒并未被认为对鸟类具有致病性，但就在那时，以色列出现了一种能够导致多种鸟类出现脑炎和麻痹症状继而死亡的毒力更强的毒株。
Before 1997 WNV was not considered pathogenic for birds, but at that time in Israel a more virulent strain caused the death of different bird species presenting signs of encephalitis and paralysis.
今年的季节流感疫苗含有三种流感病毒——一种甲型（H3N2）病毒，一种与猪流感毒株无关的常规季节性甲型（H1N1）病毒，以及一种乙型病毒。
This year’s seasonal vaccine contains three influenza viruses — one A (H3N2) virus, one regular seasonal A (H1N1) virus unrelated to the swine flu strain and one B virus.
为了验证此一想法，研究人员培育出三种酵母突变株。
To test this idea, the researchers created three mutant strains of yeast.
古斯塔沃·帕拉西奥斯正在对一种刚从一只西班牙蝙蝠中发现的新的埃博拉病毒株进行基因测序。——这是个令人不安的消息，因为这种病毒以往只在非洲地区发现过。
Gustavo Palacios was sequencing the genes from a new strain of Ebola virus found in a bat in Spain - a worrisome development, since the fatal virus has almost never been found outside Africa.
在美国旧金山，发现了一种对现有市场上的所有蛋白酶抑制剂都耐药的HIV病毒株。
An HIV strain resistant to all protease inhibitor drugs currently on the market turns up in San Francisco.
他们发现HPV16—一种最常见的引发癌症的株状病毒在百分之72的癌症患者的肿瘤中都出现了。
They found HPV16 - one of the most common cancer-causing strains of the virus - was present in the tumours of 72 per cent of cancer patients.
在加利福尼亚病毒样本中发现的两种菌株的基因很常见，属于北美和欧亚猪流感株。
The two strains whose genes are found in the hybrid belong to influenza families known generally as North American and Eurasian pig flu.
被称为“猪流感”的病毒是一种新的甲型H1N 1流感病毒株。墨西哥的感染和死亡人数最多。
Mexico has the highest number of deaths and infections of the flu, which is caused by a new strain of the influenza a H1N1 virus.
这样一来，植株就可以排列的更为紧密，每英亩产量也随之翻番，每一层楼内都可以种好几排矮株作物。
So plants could be packed tighter, doubling yield per acre, and multiple layers of dwarf crops could be grown per floor.
例如那张梅花八便是一株有八片大花瓣的大树，一种表现森林的怪诞手法。
The eight of clubs, for instance, represented a huge tree bearing eight enormous trefoil leaves, a sort of fantastic personification of the forest.
这两种抗体具有广泛的中和性，也就是说对目前发现的数千种HIV毒株中的大部分都适用。
They are 'broadly neutralizing,' which means they can target most of the many thousands of HIV strains.
在关于月亮的神话中，嫦娥喝下了不死药，而吴刚砍伐着一株永远砍不倒的桂树，这些意象都包含着一种“永生”的观念。
According to the myth of the moon, Chang E drank the elixir of life and Wu Kang cut down the cassia tree which can restore itself with each blow, implying an immortal spirit of life.
答：疫苗衍生脊髓灰质炎病毒(VDPV)是一种罕见的脊髓灰质炎病毒株，由口服脊髓灰质炎疫苗(opv)里的病毒株遗传变异而来。
A: a vaccine-derived poliovirus (VDPV) is a rare strain of poliovirus, genetically mutated from the strain contained in oral polio vaccine (OPV).
H1和N1是这一种新型病毒株表面蛋白名称。
The H1 and N1 in the name of the new strain refer to proteins on the virus's surface.
有些病人感染的病毒株对其他所有常用药物都产生了耐药性，这两种新的药物为他们带来了希望。
These two new drugs offered hope to patients infected with virus strains resistant to almost all other classes of drugs designed to fight aids.18.
有些病人感染的病毒株对其他所有常用药物都产生了耐药性，这两种新的药物为他们带来了希望。
These two new drugs offered hope to patients infected with virus strains resistant to almost all other classes of drugs designed to fight aids.18.
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