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1.

Background

Marriage benefits both individuals and societies, and is a fundamental determinant of health. Until recently same sex couples have been excluded from legally recognized marriage in the United States. Recent debate around legalization of same sex marriage has highlighted for anti-same sex marriage advocates and policy makers a concern that allowing same sex couples to marry will lead to a decrease in opposite sex marriages. Our objective is to model state trends in opposite sex marriage rates by implementation of same sex marriages and other same sex unions.

Methods and Findings

Marriage data were obtained for all fifty states plus the District of Columbia from 1989 through 2009. As these marriage rates are non-stationary, a generalized error correction model was used to estimate long run and short run effects of same sex marriages and strong and weak same sex unions on rates of opposite sex marriage. We found that there were no significant long-run or short run effects of same sex marriages or of strong or weak same sex unions on rates of opposite sex marriage.

Conclusion

A deleterious effect on rates of opposite sex marriage has been argued to be a motivating factor for both the withholding and the elimination of existing rights of same sex couples to marry by policy makers–including presiding justices of current litigation over the rights of same sex couples to legally marry. Such claims do not appear credible in the face of the existing evidence, and we conclude that rates of opposite sex marriages are not affected by legalization of same sex civil unions or same sex marriages.  相似文献   

2.
北草蜥几种消化酶活力比较   总被引:1,自引:0,他引:1  
应用酶学分析法测定了越冬后北草蜥胃、肠组织中蛋白酶、淀粉酶、纤维素酶的活力。结果表明 ,不同年龄、性别的北草蜥同一组织中消化酶活力有显著差异 ;不同地理种群的北草蜥同一组织中消化酶活力有显著差异 ;不同消化酶在北草蜥同一组织中的活力有显著差异 ;在北草蜥不同的组织中同一消化酶的活力有显著差异。说明北草蜥消化酶的活力与年龄、性别、部位和地理环境等因素有关 ,受食物组成、能量需求和遗传等因素的影响 ,产生了不同的酶活力和分布。这也说明生物长期适应环境 ,形成了不同的代谢水平  相似文献   

3.
In 1905 two different etiologic agents for syphilis were proposed in Berlin, one, the Cytorrhyctes luis, by John Siegel, the other, Spirochaete pallida, by Fritz Schaudinn. Both scientists were pupils of Franz Eilhard Schulze, and were outsiders to the Berlin medical establishment. Both belonged to the same thought collective, used the same thought style, and started from the same supposition that the etiologic agent of syphilis must be a protist. Both used the same morphological approach, the same microscopes and the same stains. Both presented their findings in the same societies, used the same rhetoric, published in the same journals, used the same arguments to criticise each other's shortcomings. Both were backed by powerful institutions and enlisted the support of prestigious patrons. Within half a year, the scientific community at large had in its overwhelming majority accepted Schaudinn's results and rejected those of Siegel. Social forces thus cannot be shown to have played any role in deciding the issue. Ludwik Fleck's suggestion that ‘appropriate influence’ and a ‘proper measure of publicity throughout the thought collective’ would have been sufficient for Siegel's ideas to win the day is untenable.  相似文献   

4.
Reiman J 《Bioethics》2007,21(6):329-341
Lee claims that foetuses and adult humans are phases of the same identical substance, and thus have the same moral status because: first, foetuses and adults are the same physical organism, and second, the development from foetus to adult is quantitative and thus not a change of substance. Versus the first argument, I contend that the fact that foetuses and adults are the same physical organism implies only that they are the same thing but not the same substance, much as living adults and their corpses are the same thing (same body) but not the same substance. Against Lee's second argument, I contend that Lee confuses the nature of a process with the nature of its result. A process of quantitative change can produce a change in substance. Lee also fails to show that foetuses are rational and thus have all the essential properties of adults, as required for them to be the same substance. Against the pro-choice argument from asymmetric value (that only the fact that a human has become conscious of its life and begun to count on its continuing can explain human life's asymmetric moral value, i.e. that it is vastly worse to kill a human than not to produce one), Lee claims that foetus's lives are asymmetrically valuable to them before consciousness. This leads to counterintuitive outcomes, and it confuses the goodness of life (a symmetric value that cannot account for why it is worse to kill a human than not produce one) with asymmetric value.  相似文献   

5.
赵赣 《生物学杂志》2009,26(5):91-91
磷酸果糖激酶-1与磷酸果糖激酶-2催化的反应性质、底物都相同,但是它们的产物是不同的。因此.严格的说它们不是同工酶。  相似文献   

6.
用来自日本和美国的立枯丝核菌8个融合群11个类群代表菌株进行可溶性蛋白质电泳,其结果表明,各融合群及亚群之间电泳图谱有显著差异,而同一类群菌株的电泳图谱则相似。分析来源于华东等地已鉴定的融合类群117个菌株的电泳图谱显示,同一融合群内菌株,虽然采集地区、寄主植物或致病力不同,其蛋白质图谱仍十分相似;而不同融合类群的菌株,即使在同一田块中同一种寄主植物上引起相似病害,其图谱也显示出明显差异。本文就上述可溶性蛋白质图谱显示的结果与其它研究者在血清学、DNA同源性.酯酶等生化水平上对融合群的研究结果进行了比较和探讨。  相似文献   

7.
青海高原高寒草甸植物柔软紫苑和糙毛鹅冠草,在同一海拔高度(3200m),由于种的不同,净光合速率和表观光合量子效率(AQY=1/AQR)也不同。双子叶植物柔软紫苑较单子叶植物糙毛鹅冠草高一些。同一垂穗披碱草,而在不同海拔高度(2300m和3200m),由于海拔和气压不同,Pn和AQY也不同。在高海拔地区(3200m),长期生长的垂穗披碱草的Pn和AQY较低海拔地区(2300m)同一植物的低,在青海  相似文献   

8.
紫胶虫的有效性比   总被引:1,自引:0,他引:1  
利用前人调查数据及近年研究结果,比较分析了几种紫胶虫的有效性比。结果表明,在同一种寄主植物上,相同的世代,不同年份间,田紫胶虫有效性比出现差异;相同年份、相同世代,在不同寄主植物上的田紫胶虫和紫胶蚧有效性比出现差异;在相同的寄主植物上,田紫胶虫和信德紫胶虫在一年中的2个不同世代的有效性比存在差异;对于同一种寄主植物,在相同年份的同一个世代,紫胶蚧和信德紫胶虫有效性比出现一定差异;在相同年份的同一个世代,不同种胶在相同寄主植物上,田紫胶虫的有效性比出现变化。环境温湿度和寄主植物的结构、营养和生长速度等对紫胶虫的有效性比可能产生影响。紫胶虫性比偏斜的机制可能同时遵循局域交配竞争和局域资源竞争。  相似文献   

9.
Previous work has shown that the contact inhibition that occurs among roots of Ambrosia dumosa shrubs has a self/nonself recognition capability. In the current study, we investigated some of the geographic and genotypic dimensions of this recognition capability by using root observation chambers to observe the effects of encounters of individual roots on root elongation rates. We measured such effects in encounters between roots of plants from the same region and compared these to effects in encounters between roots of plants from two different regions. We also measured effects of encounters between roots of plants from the same clones and compared these to effects of encounters of roots of plants from different clones. Roots of plants from the same region (population) showed the usual “nonself” precipitous decline in elongation rates following contact, but when roots of plants from different regions contacted each other, elongation rates continued unchanged. When roots of separate plants from the same clone contacted each other, the same “nonself” precipitous decline in elongation rates as seen in encounters between roots of plants of different clones from the same region occurred. Meanwhile, in these same experiments “self” contacts between sister roots connected to the same plants resulted in no changes in elongation rates. Thus, differences between individuals from two geographically separate populations of Ambrosia dumosa may be sufficient to thwart the “nonself,” population-level recognition of similarity apparently necessary for contact inhibition. Furthermore, the “self” recognition mechanism, which precludes contact inhibition between two roots on the same plant, appears to be physiological rather than genetic in nature.  相似文献   

10.
在蟾蜍视网膜的视杆外段上进行片膜钳记录.在同一片膜中,8-Br-cGMP开启的通道,似乎是cGMP所开启的同一光敏感通道.在相同的片膜电位下,由同一片膜诱发同样大小的膜电流,所灌流的8-Br-cGMP溶液的浓度要大大低于cGMP溶液的浓度.再者,8-Br-cGMP被磷酸二酯酸水解的速率,比cGMP的要慢得多.结果表明,在开启视杆外段的光敏感通道的过程中,cGMP分子中的3',5'-环一磷酸可能起主要作用.  相似文献   

11.
miRNAs是一类-22nt、在转录后调节mRNAs表达的内源性非编码RNA。人类miRNA具有成簇聚集于染色体上的特点。文章系统分析了人基因组簇内miRNA各成员的预测靶基因之间的关系,发现簇内miRNA各成员具有更多共同的靶基因,表明簇内miRNA各成员功能相似。仔细分析簇内miRNA和mRNA的结合位点,发现有两种类型:一种是簇内miRNAs可能竞争性结合同一个靶基因的同一个结合位点:另一种是簇内miRNAs可能协同结合于同一个靶基因的不同结合位点。  相似文献   

12.
本文将来源不同的球孢白僵菌菌株分别按相同地理来源和相同分离奇主进行配对培养,发现相同地理来源菌株的营养亲和型多样性要明显小于相同分离寄主的菌株,前者的P及Shannon-Wiener多样性指数分别为0.4286及0.8708,后者分别为0.7500及1.3321。这说明来源于同一地区的菌株属于同一VCG的概率要大于相同分离寄主的菌株,同时也说明相同地理来源菌株的遗传相似性要高于相同分离寄主菌株的遗传相似性。  相似文献   

13.
小麦体细胞无性系SSR位点的遗传变异特性分析   总被引:2,自引:0,他引:2  
研究结果表明:(1)小麦体细胞无性系SSR位点变异类型有:扩增片段迁移率的变大或变小、扩增片段缺失以及新的扩增片段;(2)变异特点为:变异频率与基因型有关,不同染色体组上的SSR位点变异频率不同,而不同无性系后代的SSR位点变异频率也不同;(3)同一SSR位点的变异类型在同一基因型的无性系后代中变异表现一致,在不同基因型无性系后代中的变异表现不同,有的SSR位点在无性系后代中表现出一致的变异,而有的则不一致。  相似文献   

14.
We observed anastomosis between hyphae originating from the same spore and from different spores of the same isolate of the arbuscular mycorrhizal fungi Glomus mosseae, Glomus caledonium, and Glomus intraradices. The percentage of contacts leading to anastomosis ranged from 35 to 69% in hyphae from the same germling and from 34 to 90% in hyphae from different germlings. The number of anastomoses ranged from 0.6 to 1.3 per cm (length) of hyphae in mycelia originating from the same spore. No anastomoses were observed between hyphae from the same or different germlings of Gigaspora rosea and Scutellospora castanea; no interspecific or intergeneric hyphal fusions were observed. We monitored anastomosis formation with time-lapse and video-enhanced light microscopy. We observed complete fusion of hyphal walls and the migration of a mass of particles in both directions within the hyphal bridges. In hyphal bridges of G. caledonium, light-opaque particles moved at the speed of 1.8 +/- 0.06 microm/s. We observed nuclear migration between hyphae of the same germling and between hyphae belonging to different germlings of the same isolate of three Glomus species. Our work suggests that genetic exchange may occur through intermingling of nuclei during anastomosis formation and opens the way to studies of vegetative compatibility in natural populations of arbuscular mycorrhizal fungi.  相似文献   

15.
动物肌动蛋白基因中内含子的来源及存在意义的探讨   总被引:5,自引:0,他引:5  
吴加金  吴晓霞 《遗传学报》1998,25(5):409-415
对动物界演化过程中肌动蛋白家族内含子插入位置分布的演化规律作了分析,并对相同插入位置的内含子序列按同亚型和不同亚型作了比较。结果得出:从整个肌动蛋白家族的外显子序列高度保守性推断整个肌动蛋白家族可能是从共同的祖先蛋白进化而来的;从同亚型肌动蛋白内含子序列的类似性随进化距离而变化,但在短进化距离的物种间,类似性都较高,不同亚型肌动蛋白内含子序列的类似性都较低,即使是同一物种(如人),类似性也远低于同亚型但进化距离较近的物种,由此可推断,同亚型肌动蛋白的内含子序列可能从共同祖先进化,不同亚型肌动蛋白的内含子序列从不同祖先进化,综上推断可导出内含子可能是在蛋白异化过程中获得的:还发现内含子在肌动蛋白家族编码基因中位置的分布随进化方向不同而逐步形成两种截然不同的模式,由此提出了内含子的位置分布与动物演化方向之间可能具有某种必然联系,为内含子的存在提出了某种依据。  相似文献   

16.
乳酸脱氢酶与酯酶同工酶同板染色法   总被引:4,自引:0,他引:4  
介绍一种在同一块凝胶板上染乳酸脱氢酶(LDH)与酯酶(EST)的染色方法. 该同板染色法利用两种同工酶显色反应互不干扰和颜色不同的特点, 先染LDH, 后染EST, 可以在同一块胶板上得到两种同工酶清晰的酶带, 每一种酶的酶带与单板染色的酶带完全一样. 这种染色法, 能节省同工酶分析所需的试剂、时间和经费, 也便于样品的鉴定与比较, 是一种经济有效的方法. 此方法, 同样适用于苹果酸脱氢酶(MDH)与酯酶等同工酶的同板染色.  相似文献   

17.
A note on effective population size with overlapping generations   总被引:13,自引:7,他引:6       下载免费PDF全文
Hill WG 《Genetics》1979,92(1):317-322
A simple derivation is given for a formula obtained previously for the effective size of random-mating populations with overlapping generations. The effective population size is the same as that for a population with discrete generations having the same variance of lifetime family size and the same number of individuals entering the population per generation.  相似文献   

18.
为了提高精制原代地鼠肾细胞狂犬病疫苗(PPHKRV)的质量,在甲醛浓度,温度和时间相同的条件下,对静置法和转瓶法灭活狂犬病毒后制成的疫苗进行了效力测定比较,结果表明采用转瓶灭活的PPHKRV效力高于静置灭活法。  相似文献   

19.
Microsatellite markers were used to test whether groups of pre‐spawning adult brook trout Salvelinus fontinalis from the same population and captured at the same location during their breeding migration comprised kin. Only weak evidence for kin associations was found at the onset of breeding: the proportion of kin captured at the same location was low and similar to the proportion found across all locations and the average relatedness of S. fontinalis captured at the same location was low. A dilution of kin associations from the feeding to breeding phase is hypothesized to stem from mainly natural mortality that reduces family size by the adult stage. The results illustrate the dynamic nature of kin associations between consecutive life stages, even within the same fish population.  相似文献   

20.
Human head lice and body lice are morphologically and biologically similar but have distinct ecologies. They were shown to have almost the same basic genetic content (one gene is absent in head lice), but differentially express certain genes, presumably responsible for the vector competence. They are now believed to be ecotypes of the same species (Pediculus humanus) and based on mitochondrial studies, body lice have been included with head lice in one of three clades of human head lice (Clade A). Here, we tested whether head and body lice collected from the same host belong to the same population by examining highly polymorphic intergenic spacers. This study was performed on lice collected from five homeless persons living in the same shelter in which Clade A lice are prevalent. Lice were individually genotyped at four spacer loci. The genetic identity and diversity of lice from head and body populations were compared for each homeless person. Population genetic structure was tested between lice from the two body regions and between the lice from different host individuals.We found two pairs of head and body lice on the same homeless person with identical multi locus genotypes. No difference in genetic diversity was found between head and body louse populations and no evidence of significant structure between the louse populations was found, even after controlling for a possible effect of the host individual. More surprisingly, no structure was obvious between lice of different homeless persons.We believe that the head and body lice collected from our five subjects belong to the same population and are shared between people living in the same shelter. These findings confirm that head and body lice are two ecotypes of the same species and show the importance of implementing measures to prevent lice transmission between homeless people in shelters.  相似文献   

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