3,213 research outputs found

    Random Chance or Loaded Dice: The Politics of Judicial Designation

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    [Excerpt] “In the 1950s and 1960s, the southern states struggled to respond to the civil rights decisions being issued by the U.S. Supreme Court as well as the new civil rights laws being passed by Congress. The judicial battleground for this perfect storm of evasion and massive resistance was found in the “old” Fifth Circuit Court of Appeals, which encompassed the states of Alabama, Florida, Georgia, Louisiana, Mississippi, and Texas. In the “old” Fifth Circuit, a minority of liberal appeals court judges—sympathetic to the civil rights movement—used all legal and administrative power at their disposal to make sure that the federal district and appeals courts were complying with the U.S. Supreme Court’s mandate in Brown v. Board of Education. In their ground-breaking book A Court Divided: The Fifth Circuit Court of Appeals and the Politics of Judicial Reform, political scientists Deborah J. Barrow and Thomas G. Walker carefully examined the political behavior of these aforementioned liberal appeals court judges and found evidence that Elbert Parr Tuttle, the Fifth Circuit’s chief judge from 1960 to 1967, was manipulating, or “gerrymandering,” the assignment of appeals court judges to both three-judge district court panels, and three-judge appellate court panels to guarantee that the panels had at least two liberal judges who would enforce the Supreme Court’s desegregation rulings.

    Formation of viable cell fragments by treatment with colchicine

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    Time-lapse cinematography of human fibroblasts revealed that mitotic cells separated into numerous cell fragments containing varying amounts of chromatin and cytoplasm when treated with colchicine. As cell fragments were very loosely attached to the surface of the culture vessel during their formation, they could be easily detached like mitotic cells by gently shaking the vessel and thus separated from normal interphase cells. Fragments obtained by this procedure were able to exclude trypan blue indicating, therefore, an intact cell membrane. When placed into Petri dishes many of them attached to and even spread out on the surface. Five hours later the majority of the attached fragments incorporated [3H]leucine. Time-lapse films showed that fragments were able to extend and retract pseudopodia at least for several hours after their formation. Although the fragments degenerated within a few days, in the present experiments the possibility was not excluded that fragments which had lost only a very small amount of chromatin and cytoplasm survived for longer periods of time. The observations clearly indicate viability of many newly formed fragments

    Seafood Safety and Trade

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    Food Consumption/Nutrition/Food Safety, International Relations/Trade,

    Rabl's model of the interphase chromosome arrangement tested in Chinise hamster cells by premature chromosome condensation and laser-UV-microbeam experiments

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    In 1885 Carl Rabl published his theory on the internal structure of the interphase nucleus. We have tested two predictions of this theory in fibroblasts grown in vitro from a female Chinese hamster, namely (1) the Rabl-orientation of interphase chromosomes and (2) the stability of the chromosome arrangement established in telophase throughout the subsequent interphase. Tests were carried out by premature chromosome condensation (PCC) and laser-UV-microirradiation of the interphase nucleus. Rabl-orientation of chromosomes was observed in G1 PCCs and G2 PCCs. The cell nucleus was microirradiated in G1 at one or two sites and pulse-labelled with 3H-thymidine for 2h. Cells were processed for autoradiography either immediately thereafter or after an additional growth period of 10 to 60h. Autoradiographs show unscheduled DNA synthesis (UDS) in the microirradiated nuclear part(s). The distribution of labelled chromatin was evaluated in autoradiographs from 1035 cells after microirradiation of a single nuclear site and from 253 cells after microirradiation of two sites. After 30 to 60h postincubation the labelled regions still appeared coherent although the average size of the labelled nuclear area fr increased from 14.2% (0h) to 26.5% (60h). The relative distance dr, i.e. the distance between two microirradiated sites divided by the diameter of the whole nucleus, showed a slight decrease with increasing incubation time. Nine metaphase figures were evaluated for UDS-label after microirradiation of the nuclear edge in G1. An average of 4.3 chromosomes per cell were labelled. Several chromosomes showed joint labelling of both distal chromosome arms including the telomeres, while the centromeric region was free from label. This label pattern is interpreted as the result of a V-shaped orientation of these particular chromosomes in the interphase nucleus with their telomeric regions close to each other at the nuclear edge. Our data support the tested predictions of the Rabl-model. Small time-dependent changes of the nuclear space occupied by single chromosomes and of their relative positions in the interphase nucleus seem possible, while the territorial organization of interphase chromosomes and their arrangement in general is maintained during interphase. The present limitations of the methods used for this study are discussed

    Testing the neutrality of matter by acoustic means in a spherical resonator

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    New measurements to test the neutrality of matter by acoustic means are reported. The apparatus is based on a spherical capacitor filled with gaseous SF6_6 excited by an oscillating electric field. The apparatus has been calibrated measuring the electric polarizability. Assuming charge conservation in the β\beta decay of the neutron, the experiment gives a limit of ϵp-e11021\epsilon_\text{p-e}\lesssim1\cdot10^{-21} for the electron-proton charge difference, the same limit holding for the charge of the neutron. Previous measurements are critically reviewed and found incorrect: the present result is the best limit obtained with this technique

    Analysis of chromosome positions in the interphase nucleus of Chinese hamster cells by laser-UV-microirradiation experiments

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    Unsynchronized cells of an essentially diploid strain of female Chinese hamster cells derived from lung tissue (CHL) were laser-UV-microirradiated (=257 nm) in the nucleus either at its central part or at its periphery. After 7–9 h postincubation with 0.5 mM caffeine, chromosome preparations were made in situ. Twenty-one and 29 metaphase spreads, respectively, with partial chromosome shattering (PCS) obtained after micro-irradiation at these two nuclear sites, were Q-banded and analyzed in detail. A positive correlation was observed between the frequency of damage of chromosomes and both their DNA content and length at metaphase. No significant difference was observed between the frequencies of damage obtained for individual chromosomes at either site of microirradiation. The frequency of joint damage of homologous chromosomes was low as compared to nonhomologous ones. Considerable variation was noted in different cells in the combinations of jointly shattered chromosomes. Evidence which justifies an interpretation of these data in terms of an interphase arrangement of chromosome territories is discussed. Our data strongly argue against somatic pairing as a regular event, and suggest a considerable variability of chromosome positions in different nuclei. However, present data do not exclude the possibility of certain non-random chromosomal arrangements in CHL-nuclei. The interphase chromosome distribution revealed by these experiments is compared with centromere-centromere, centromere-center and angle analyses of metaphase spreads and the relationship between interphase and metaphase arrangements of chromosomes is discussed

    State scaling of continuous-time sigma-delta modulators

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    In this paper, the common method of scaling the feedback coefficients of continuous time sigma delta modulators in order to stabilize the system is enhanced. The presented approach scales the different states of the system instead of the coefficients. The new corresponding coefficients are then calculated from the solution of the state space description. Therewith, it is possible to tune the maximum out-of-band gain directly in continuous time. In addition, the input amplitude distribution between each quantization level of multi bit sigma-delta modulator can be adapted
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