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1.
This paper discusses the Brazilian Supreme Court ruling on the case of anencephaly. In Brazil, abortion is a crime against the life of a fetus, and selective abortion of non-viable fetuses is prohibited. Following a paradigmatic case discussed by the Brazilian Supreme Court in 2004, the use of abortion was authorized in the case of a fetus with anencephaly. The objective of this paper is to analyze the ethical arguments of the case, in particular the strategy of avoiding the moral status of the fetus, the cornerstone thesis of the Catholic Church.  相似文献   

2.
In this paper a general deterministic discrete-time metapopulation model with a finite number of habitat patches is analysed within the framework of adaptive dynamics. We study a general model and prove analytically that (i) if the resident populations state is a fixed point, then the resident strategy with no migration is an evolutionarily stable strategy, (ii) a mutant population with no migration can invade any resident population in a fixed point state, (iii) in the uniform migration case the strategy not to migrate is attractive under small mutational steps so that selection favours low migration. Some of these results have been previously observed in simulations, but here they are proved analytically in a general case. If the resident population is in a two-cyclic orbit, then the situation is different. In the uniform migration case the invasion behaviour depends both on the type of the residents attractor and the survival probability during migration. If the survival probability during migration is low, then the system evolves towards low migration. If the survival probability is high enough, then evolutionary branching can happen and the system evolves to a situation with several coexisting types. In the case of out-of-phase attractor, evolutionary branching can happen with significantly lower survival probabilities than in the in-phase attractor case. Most results in the two-cyclic case are obtained by numerical simulations. Also, when migration is not uniform we observe in numerical simulations in the two-cyclic orbit case selection for low migration or evolutionary branching depending on the survival probability during migration.  相似文献   

3.
探讨应用电子阴道镜在寻找妊娠期阴道出血原因方面的价值。方法:对我院2004年5月-2006年11月64例非产科原因孕期阴道流血的孕妇,进行电子阴道镜检查及颈管分泌物培养和镜下定位活检。结果:阴道镜下发现宫颈赘生物12例,其中2例坏死,10例明显充血水肿;宫颈炎伴活动性出血2例,宫颈炎无活动性出血18例;正常宫颈16例;宫颈上皮内瘤样病变图象15例;宫颈分泌物培养阳性23例。结论:妊娠期不规则阴道出血原因复杂,阴道镜检查能较快排除与查明宫颈及阴道病变所导致的出血。  相似文献   

4.
The case of industrial melanism in the peppered moth has been used as a teaching example of Darwinian natural selection in action for half a century. However, over the last decade, this case has come under attack from those who oppose Darwinian evolution. Here, the main elements of the case are outlined and the reasons that the peppered moth case became the most cited example of Darwinian evolution in action are described. Four categories of criticism of the case are then evaluated. Criticisms of experimental work in the 1950s that centered on lack of knowledge of the behavior and ecology of the moth, poor experimental procedure, or artificiality in experiments have been addressed in subsequent work. Some criticisms of the work are shown to be the result of lack of understanding of evolutionary genetics and ecological entomology on the part of the critics. Accusations of data fudging and scientific fraud in the case are found to be vacuous. The conclusion from this analysis of criticisms of the case is that industrial melanism in the peppered moth is still one of the clearest and most easily understood examples of Darwinian evolution in action and that it should be taught as such in biology classes.  相似文献   

5.
Despite the fact that migration occurs in a wide variety of taxa worldwide, little is known about the conditions under which migration is expected to evolve from an ancestral resident population. We develop a model that focuses on ecological factors affecting the evolution of migration in a seasonal environment within a genetically explicit framework. We model the evolution of migration for two common types of migration: ‘shared breeding where migrants share a breeding ground with residents and migrate to a separate non-breeding area, versus ‘shared non-breeding’, where migrants share a non-breeding ground with residents and migrate to a separate breeding area. Ecologically, migration is more easily established in the shared-breeding case versus the shared-non-breeding case. Genetically, the additive effect of a migratory allele affects its establishment more in the shared-non-breeding case versus the shared-breeding case, whereas the dominance effect of the allele affects its establishment more in the shared-breeding case versus the shared-non-breeding case. Generally, migratory alleles can invade even when residents are competitively superior to migrants during the shared season. Partial migration occurs when the population is polymorphic for migratory and non-migratory alleles, and is dependent upon which season is shared and the additive and dominance behaviour of the migratory allele.  相似文献   

6.
The case series is the most prevalent type of clinical research in the plastic surgery literature. However, this is a lower level study design in the hierarchy of evidence. The case series is nevertheless a useful hypothesis generator for future studies. These in turn can be tested with more robust study designs such as the randomized controlled trial. Because the case series remains the most common study design used to communicate our new innovations, there is a need to improve its reporting so that readers will know why the study was undertaken, what the results were, and how the results affect patient care. The authors provide a guide to help future investigators improve the conduct and the reporting of their case series.  相似文献   

7.
The case of a vessel, which supplies a region through which it passes with some substance, is considered for the situation in which the permeability is the limiting factor. Diffusion parallel to the vessel is neglected. The substance may, however, be consumed proportional to its concentration in the inner or outer region. A solution is given for the case in which the input is an arbitrary function of time. It is suggested that the results may be applied in some cases to data on the injection of substances into blood vessels, or they may be applied to the transient effects in the case of vapors or gases passing through the respiratory passages.  相似文献   

8.
One case of human palpebral dirofilariasis by Dirofilaria repens, in Abruzzo, is described. It is the first case reported in this region. The parasite was released following the energetic rubbing of the palpebral area, with the result in the spontaneous recovery of the patient.  相似文献   

9.
The formulation of hard selection is reviwed in the context of haploid viabilities and the criteria for stability of the fixation states are given. In contrast to soft selection, both fixation states can be simultaneously stable. However, this is not possible if the migration matrix is positive definite. In the case of only two demes there is at most one polymorphic equilibrium as occurs under soft selection, but the internal equilibrium may be unstable in contrast to the soft selection case. The question of hard versus soft protection is posed in the context of haploid viabilities and the principle hard protection implies soft protection holds with a similar degree of generality as in the diploid case.  相似文献   

10.
A class of viability models that generalize the standard additive model for the case of pairwise additive by additive epistatic interactions is considered. Conditions for existence and stability of steady states in the corresponding two-locus model are analyzed. Using regular perturbation techniques, the case when selection is weaker than recombination and the case when selection is stronger than recombination are investigated. The results derived are used to make conclusions on the dependence of population characteristics on the relation between the strength of selection and the recombination rate.  相似文献   

11.
A case of generalized avian tuberculosis in sheep is described. The case was somewhat unusual. No calcification and slight encapsulation together with scanty participation of epithelioid cells in the inflammations were typical features. The source of the infection, in an area where this disease is rare, is not known.  相似文献   

12.
分析克拉玛依市麻疹流行状况及预防控制措施,为消除麻疹提供依据。采用描述流行病学分析方法,对2008年克拉玛依市麻疹资料进行分析。结果显示,克拉玛依市2008年麻疹发病率为38.83/10万(138/355381),呈高度散发,较2007年有所上升。发病高峰在3~5月,发病数占全年的83.33%。年龄分布大年龄组高于小年龄组,>20岁年龄组病例占50.00%,<1岁病例占18.84%;流动人口发病占51.11%。应切实提高麻疹常规免疫接种率和做好入托、入学儿童查验预防接种证工作,加强麻疹监测,提高实验室确诊病例的比例。  相似文献   

13.
We report a case of chimpanzee trisomy 22 in a captive-born female. Because chromosome 22 in great apes is homologous to human chromosome 21, the present case is analogous to human trisomy 21, also called Down syndrome. The chimpanzee in the present case experienced retarded growth; infantile cataract and vision problems, including nystagmus, strabismus, and keratoconus; congenital atrial septal defect; and hypodontia. All of these symptoms are common in human Down syndrome. This case was the second reported case of trisomy 22 in the chimpanzee. The chimpanzee in our case became blind by 7 years old, making social life with other chimpanzees difficult, but opportunities to interact with other conspecific individuals have been offered routinely. We believe that providing her with the best care over the course of her life will be essential.  相似文献   

14.
A new case of partial trisomy 13 through unbalanced de novo translocation t(X;13) is reported. In situ hybridization has been used to specify breakage points on the X chromosome. This case is cytogenetically comparable with another reported case; the phenotypical aspect of these two patients is however different. This discrepancy is discussed.  相似文献   

15.
In this review, studies of the role of head movements in generating motion parallax which is used in depth perception are examined. The methods used and definitiveness of the results vary with the animal groups studied. In the case of insects, studies which quantify motor outputs have provided clear evidence that motion parallax evoked by head movements is used for distance estimation and depth perception. In the case of birds and rodents, training studies and analyses of the head movements themselves have provided similar indications. In the case of larger mammals, due to a lack of systematic experiments, the evidence is less conclusive.  相似文献   

16.
A recently introduced approximation method is applied in order to obtain an expression for the amount of a substance remaining within a nerve at any time, the nerve having been soaked for a long time in a solution containing the substance until the time zero when it is bathed in the same solution but without the substance. The case of a uniform nerve without a sheath leads to substantially the same results as previously obtained by A. V. Hill (1928) for this case. A solution is given for the case of a nerve without sheath but having fibers which are permeable. In this case it is shown how an effective diffusion coefficient for the interstitial fluid can be obtained, as well as the effective inward and outward fiber permeabilities. A solution is given for the case of a nerve with a sheath in which the substance considered does not penetrate the fibers, and it is shown how the effective diffusion coefficients of the sheath and the interstitial fluid can be obtained.  相似文献   

17.
结合激光雷达分析上海地区一次连续浮尘天气过程   总被引:4,自引:0,他引:4  
马井会  顾松强  陈敏  施红  张国琏 《生态学报》2012,32(4):1085-1096
通过分析2010年3月至20日至3月22日上海地区一次典型的连续浮尘天气过程,利用激光雷达数据资料反演得到的气溶胶消光系数图和垂直廓线图,结合地面气象数据和气溶胶观测资料以及卫星遥感资料,初步得出了此次连续浮尘天气形成的原因。外源性输入和垂直风场分布是导致此次浮尘天气发生的重要原因,大气层结变化决定着浮尘天气发生的强度,当存在接地逆温时,浮尘天气维持,而太阳辐射强度变化决定着边界层高度的变化。第一次浮尘过程以大颗粒污染为主,且在消光作用中散射性气溶胶的贡献大于吸收性气溶胶,而第二次回流浮尘过程则PM2.5比重上升,吸收性气溶胶对消光系数的贡献与散射性气溶胶大体相当。  相似文献   

18.
E. Zalan  W. D. Leers  N. A. Labzoffsky 《CMAJ》1962,87(13):714-715
Reovirus Type 2 was isolated from three patients aged 5, 9 and 10 years. The etiological role of Reovirus in one case was confirmed by demonstration of antibodies in convalescent serum and none in acute serum. Symptoms in this case were suggestive of infectious mononucleosis. In the second case, rhinitis and non-purulent otitis were preceded by two waves of fever, abdominal pain and emesis. Acute serum was not available but convalescent serum had a high titre to a Reovirus, thus supporting a Reovirus etiology. Symptoms in the third case were fever, intermittent headache, neck stiffness, abdominal cramps and weakness of a leg. Because of the unavailability of convalescent serum, evidence of a Reovirus etiology was incomplete. No attempt is made to associate Reovirus with a particular clinical picture. Rather, attention is simply drawn to the existence of Reovirus infections in Ontario.  相似文献   

19.
Studies have been carried out on the effects of mutations in nine distinct genes which regulate ribosome biosynthesis in yeast. Although some mutants have more extensive effects than others, in each case there is an inhibition by 50 to 80% of the synthesis of ribosomal precursor RNA. In each case there is an inhibition of the processing of that RNA which is made, ranging from 80 to 95%. In each case there is degradation of 50 to 70% of that RNA which is processed. Much of the RNA which survives to become the mature 25 s and 18 s species is found in functioning polyribosomes.  相似文献   

20.
Theoretical basis and favourable therapeutical application of magnetic field in case of trophic ulcerations of the lower limbs are discussed. As a clinical example of such action a case of a 39-year old female patient with trophic ulceration of the leg is presented. Practical advantages of magnetotherapy in similar to the described case patients are suggested.  相似文献   

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