2,319 research outputs found

    Sectionalism and the Representation Debate, 1787-1792

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    From 1787 until 1792 the issue of the apportionment of representatives in the House of Representatives was the focus of spirited debate in American politics. The central issue at stake was the size and influence of each of the sections in future Congresses. The representation issue was first debated during the Constitutional Convention in 1787. After a temporary settlement of the representation guestion in the Convention, the First Congress re-opened the apportionment debate. The result was a constitutional amendment that would have significantly increased the size of the House of Representatives. After that amendment failed to pass the states, the Second Congress finally passed in 1792 an apportionment bill that increased the House in size in time for the convening of the Third Congress in March 1793. No historian that I know of has addressed the representation debate after the Constitutional Convention. Therefore, the details of the debate over the apportionment amendment remained unexamined. Additionally, the contest in the Second House to increase the size of the House has been virtually ignored. This paper therefore addresses the representation debate from 1787 to 1792. Starting with the Constitutional Convention of 1787, I have traced the representation question through the First Congress and the failed apportionment amendment to the debate\u27s conclusion in the Second Congress. Both primary and secondary sources were used in the research of this paper. Additionally, legislative roll call analysis was used to determine the degree of sectionalism surrounding the representation debate in the Second Congress. The conclusion of my research is that North-South sectionalism played a significant role in the apportionment debate. The question of slavery\u27s place in the apportionment of representatives was central to the debate in the Constitutional Convention. Although the slavery question was settled by the three-fifths compromise, the North and the South, after the Convention, divided along sectional lines on the question of how large of an increase in the size of the House of Representatives was necessary. By the Second Congress the South had split with the North on that issue. But within the North, two distinct voting blocs emerged. The New England and the Mid-Atlantic states fractured over the details of limiting the increase in the number of representatives in the House. Thus, by 1792, a distinct North-South sectionalism over the size and make-up of the House of Representatives was present in American politics

    High resistivity and ultrafast carrier lifetime in argon implanted GaAs

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    We have investigated the optoelectronic and structural properties of GaAs that has been implanted with Ar ions and subsequently annealed. The material exhibits all the basic optical and electronic characteristics typically observed in nonstoichiometric, As implanted or low‐temperature‐grown GaAs. Annealing of Ar implanted GaAs at 600 °C produces a highly resistive material with a subpicosecond trapping lifetime for photoexcited carriers. Transmission electron microscopy shows that, instead of As precipitates, characteristic for the nonstoichiometeric GaAs, voids ranging in size from 3 to 5 nm are observed in Ar implanted and annealed GaAs. © 1996 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/69637/2/APPLAB-69-17-2569-1.pd

    Pregnancy after liver transplantation under tacrolimus

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    Background. The maternal and fetal risk of pregnancy after organ transplantation under tacrolimus has not been reported. This was prospectively studied in 27 pregnancies by 21 female liver recipients who were treated with tacrolimus before and throughout gestation. Method. Twenty- seven babies were born between October 1990 and April 1996. In 15 cases, samples were obtained at or after delivery and stored (-40°C) for comparison of tacrolimus concentration in the maternal blood with different combinations of cord and infant venous blood, breast milk, or a section of the placenta. Results. The 21 mothers had surprisingly few serious complications of pregnancy and no mortality. Two infants with 23 and 24 weeks gestation died shortly after birth. The mean birth weight of the other 25 was 2638±781 g after a gestational period of 36.0±3.3 weeks. Mean birth weight percentile for gestational age was 50.2±26.2 (median 40). On the day of delivery, the mean tacrolimus concentrations (ng/ml) were 4.3 in placenta versus 1.5, 0.7, and 0.5 in maternal, cord, and child plasma, and 0.6 in the first breast milk specimens. The infants had a 36% incidence of transient perinatal hyperkalemia (K+>7.0 meq/L) and a mild reversible renal impairment, which were thought to reflect in part maternal homeostasis. One newborn had unilateral polycystic renal disease (the only anomaly). All 25 babies have had satisfactory postnatal growth and development with a current mean weight percentile of 62±37 (median 80). Conclusions. Pregnancy by postliver transplant mothers under tacrolimus was possible with a surprisingly low incidence of the hypertension, preeclampsia, and other maternal complications historically associated with such gestations. As in previous experience with other immunosuppressive regimens, preterm deliveries were common. However, prenatal growth for gestational age and postnatal infant growth for post- partum age were normal

    Learning through the ages? Generational inequalities and inter-generational dynamics of lifelong learning

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    This exploratory paper considers the concept of generation in the context of learning across the life course. Although researchers have often found considerable inequalities in participation by age, as well as strongly articulated attitudinal differences, there have so far been only a handful of studies that have explored these patterns through the perspective of generational formations. The paper is primarily conceptual, exploratory and reflective, setting out a number of approaches to the concept of generations, most of which derive largely from debates with the ghost of Karl Mannheim; it then considers how these concepts of generation have been applied to understandings of educational inequalities in recent research in Germany and the Nordic nations. It then examines the dynamics of inter-generational relations in learning, drawing on research undertaken as part of the Teaching and Learning Research Programme. The paper argues that although inter-generational dynamics are a relatively neglected dimension of Anglophone research on life chances and learning, there is a strong case for understanding their dual roles in both inequality and cohesion. It concludes by outlining some themes and areas for further investigation in the future

    The proangiogenic capacity of polymorphonuclear neutrophils delineated by microarray technique and by measurement of neovascularization in wounded skin of CD18-deficient mice

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    Growing evidence supports the concept that polymorphonuclear neutrophils (PMN) are critically involved in inflammation-mediated angiogenesis which is important for wound healing and repair. We employed an oligonucleotide microarray technique to gain further insight into the molecular mechanisms underlying the proangiogenic potential of human PMN. In addition to 18 known angiogenesis-relevant genes, we detected the expression of 10 novel genes, namely midkine, erb-B2, ets-1, transforming growth factor receptor-beta(2) and -beta(3), thrombospondin, tissue inhibitor of metalloproteinase 2, ephrin A2, ephrin B2 and restin in human PMN freshly isolated from the circulation. Gene expression was confi rmed by the RT-PCR technique. In vivo evidence for the role of PMN in neovascularization was provided by studying neovascularization in a skin model of wound healing using CD18-deficient mice which lack PMN infi ltration to sites of lesion. In CD18-deficient animals, neo- vascularization was found to be signifi cantly compromised when compared with wild- type control animals which showed profound neovascularization within the granulation tissue during the wound healing process. Thus, PMN infiltration seems to facilitate inflammation mediated angiogenesis which may be a consequence of the broad spectrum of proangiogenic factors expressed by these cells. Copyright (c) 2006 S. Karger AG, Basel

    NLRP6 negatively regulates innate immunity and host defence against bacterial pathogens

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    Members of the intracellular nucleotide-binding and oligomerization domain (NOD)-like receptor (NLR) family contribute to immune responses through activation of nuclear factor-kappa B (NF-kappa B), type I interferon and inflammasome signalling(1). Mice lacking the NLR family member NLRP6 were recently shown to be susceptible to colitis and colorectal tumorigenesis(2-4), but the role of NLRP6 in microbial infections and the nature of the inflammatory signalling pathways regulated by NLRP6 remain unclear. Here we show that Nlrp6-deficient mice are highly resistant to infection with the bacterial pathogens Listeria monocytogenes, Salmonella typhimurium and Escherichia coli. Infected Nlrp6-deficient mice had increased numbers of monocytes and neutrophils in circulation, and NLRP6 signalling in both haematopoietic and radioresistant cells contributed to increased susceptibility. Nlrp6 deficiency enhanced activation of mitogen-activated protein kinase (MAPK) and the canonical NF-kappa B pathway after Toll-like receptor ligation, but not cytosolic NOD1/2 ligation, in vitro. Consequently, infected Nlrp6-deficient cells produced increased levels of NF-kappa B-and MAPK-dependent cytokines and chemokines. Thus, our results reveal NLRP6 as a negative regulator of inflammatory signalling, and demonstrate a role for this NLR in impeding clearance of both Gram-positive and -negative bacterial pathogens

    Measurement of the Branching Fraction for B- --> D0 K*-

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    We present a measurement of the branching fraction for the decay B- --> D0 K*- using a sample of approximately 86 million BBbar pairs collected by the BaBar detector from e+e- collisions near the Y(4S) resonance. The D0 is detected through its decays to K- pi+, K- pi+ pi0 and K- pi+ pi- pi+, and the K*- through its decay to K0S pi-. We measure the branching fraction to be B.F.(B- --> D0 K*-)= (6.3 +/- 0.7(stat.) +/- 0.5(syst.)) x 10^{-4}.Comment: 7 pages, 1 postscript figure, submitted to Phys. Rev. D (Rapid Communications

    Tractostorm 2 : Optimizing tractography dissection reproducibility with segmentation protocol dissemination

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    The segmentation of brain structures is a key component of many neuroimaging studies. Consistent anatomical definitions are crucial to ensure consensus on the position and shape of brain structures, but segmentations are prone to variation in their interpretation and execution. White-matter (WM) pathways are global structures of the brain defined by local landmarks, which leads to anatomical definitions being difficult to convey, learn, or teach. Moreover, the complex shape of WM pathways and their representation using tractography (streamlines) make the design and evaluation of dissection protocols difficult and time-consuming. The first iteration of Tractostorm quantified the variability of a pyramidal tract dissection protocol and compared results between experts in neuroanatomy and nonexperts. Despite virtual dissection being used for decades, in-depth investigations of how learning or practicing such protocols impact dissection results are nonexistent. To begin to fill the gap, we evaluate an online educational tractography course and investigate the impact learning and practicing a dissection protocol has on interrater (groupwise) reproducibility. To generate the required data to quantify reproducibility across raters and time, 20 independent raters performed dissections of three bundles of interest on five Human Connectome Project subjects, each with four timepoints. Our investigation shows that the dissection protocol in conjunction with an online course achieves a high level of reproducibility (between 0.85 and 0.90 for the voxel-based Dice score) for the three bundles of interest and remains stable over time (repetition of the protocol). Suggesting that once raters are familiar with the software and tasks at hand, their interpretation and execution at the group level do not drastically vary. When compared to previous work that used a different method of communication for the protocol, our results show that incorporating a virtual educational session increased reproducibility. Insights from this work may be used to improve the future design of WM pathway dissection protocols and to further inform neuroanatomical definitions.Peer reviewe

    Study of e+e- --> pi+ pi- pi0 process using initial state radiation with BABAR

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    The process e+e- --> pi+ pi- pi0 gamma has been studied at a center-of-mass energy near the Y(4S) resonance using a 89.3 fb-1 data sample collected with the BaBar detector at the PEP-II collider. From the measured 3pi mass spectrum we have obtained the products of branching fractions for the omega and phi mesons, B(omega --> e+e-)B(omega --> 3pi)=(6.70 +/- 0.06 +/- 0.27)10-5 and B(phi --> e+e-)B(phi --> 3pi)=(4.30 +/- 0.08 +/- 0.21)10-5, and evaluated the e+e- --> pi+ pi- pi0 cross section for the e+e- center-of-mass energy range 1.05 to 3.00 GeV. About 900 e+e- --> J/psi gamma --> pi+ pi- pi0 gamma events have been selected and the branching fraction B(J/psi --> pi+ pi- pi0)=(2.18 +/- 0.19)% has been measured.Comment: 21 pages, 37 postscript figues, submitted to Phys. Rev.

    Measurement of Branching Fraction and Dalitz Distribution for B0->D(*)+/- K0 pi-/+ Decays

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    We present measurements of the branching fractions for the three-body decays B0 -> D(*)-/+ K0 pi^+/-andtheirresonantsubmodes and their resonant submodes B0 -> D(*)-/+ K*+/- using a sample of approximately 88 million BBbar pairs collected by the BABAR detector at the PEP-II asymmetric energy storage ring. We measure: B(B0->D-/+ K0 pi+/-)=(4.9 +/- 0.7(stat) +/- 0.5 (syst)) 10^{-4} B(B0->D*-/+ K0 pi+/-)=(3.0 +/- 0.7(stat) +/- 0.3 (syst)) 10^{-4} B(B0->D-/+ K*+/-)=(4.6 +/- 0.6(stat) +/- 0.5 (syst)) 10^{-4} B(B0->D*-/+ K*+/-)=(3.2 +/- 0.6(stat) +/- 0.3 (syst)) 10^{-4} From these measurements we determine the fractions of resonant events to be : f(B0-> D-/+ K*+/-) = 0.63 +/- 0.08(stat) +/- 0.04(syst) f(B0-> D*-/+ K*+/-) = 0.72 +/- 0.14(stat) +/- 0.05(syst)Comment: 7 pages, 3 figures submitted to Phys. Rev. Let
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