3,192 research outputs found

    Geodetic research studies Final technical report

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    Geopotential surface measurement of ocean using altimeter dat

    Finding the Witch’s Mark: Female Participation in the Judicial System During the Hopkins Trials 1645-47

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    Between the years of 1645 and 1647 in East Anglia, a series of witch trials known as the Hopkins Trials took place. In all, 250 witches were accused and 100 hanged. The ability to convict a person of the crime of witchcraft relied heavily on evidence which was hard to come by given the nature of the crime of witchcraft. Tangible proof of an intangible crime was needed; this came in the form of witch’s marks. To the learned population, marks were a symbol of the witch’s covenant with the devil. To the lay person, they were called ‘teats’ and were believed to be evidence that a witch kept familiars— imps of the devil which often took the form of a small animal. The finding of marks on an accused witch was one way to increase the chances of conviction. It also often led to the witch confessing to her or his supposed crimes. Thus, those who were qualified to find marks on a witch’s body were powerful actors in the Hopkins Trials. Searchers, women who were qualified to find these marks because of their experiential knowledge of the female body, were commissioned to help in this pre-trial evidence gathering. These women were an extremely influential part of the Hopkins Trials. However, they have been largely overlooked in historical discussion of witch trials to date. In the past few decades, significant gains have been made in documenting women’s history and integrating it into historical discussion overall. The study of witch trials has not yet reached this point. Women are still discussed largely as victims. They are either victims of witchcraft, or victims because they were thought to be witches. While both these groups were certainly present, it is too simplistic a model. Women were much more than just these two things. Searchers, with their good social standing, respectability and power within the Hopkins Trials, are an example of the complexity of early modern English women’s lives. I have devoted my Departmental Honors Project to highlighting the importance of these women as a case study of the differences between women in contemporary England. Through the reading of primary sources which discuss at length the importance of marks and the testimony of women searchers, I prove that these women were not victims. They were set apart from those who were suspected of witchcraft and are an example of the attention women deserve in historical investigation

    Phylogeography of New Zealand’s coastal benthos

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    During the past 30 years, 42 molecular studies have been undertaken in New Zealand to examine the phylogeography of coastal benthic invertebrates and plants. Here, we identify generalities and/or patterns that have emerged from this research and consider the processes implicated in generating genetic structure within populations. Studies have used various molecular markers and examined taxonomic groups with a range of life histories and dispersal strategies. Genetic disjunctions have been identified at multiple locations, with the most frequently observed division occurring between northern and southern populations at the top of the South Island. Although upwelling has been implicated as a cause of this disjunction, oceanographic evidence is lacking and alternative hypotheses exist. A significant negative correlation between larval duration and genetic differentiation (r2 = 0.39, P < 0.001, n = 29) across all studies suggests that larval duration might be used as a proxy for dispersal potential. However, among taxa with short larval durations (<10 days) there was greater variability in genetic differentiation than among taxa with longer pelagic periods. This variability implies that when larval duration is short, other factors may determine dispersal and connectivity among populations. Although there has been little congruence between the phylogeographic data and recognised biogeographic regions, recent research has resolved population subdivision at finer spatial scales corresponding more closely with existing biogeographic classifications. The use of fast-evolving and ecologically significant molecular markers in hypothesis-driven research could further improve our ability to detect population subdivision and identify the processes structuring marine ecosystems

    Guiding of Rydberg atoms in a high-gradient magnetic guide

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    We study the guiding of 87^{87}Rb 59D5/2_{5/2} Rydberg atoms in a linear, high-gradient, two-wire magnetic guide. Time delayed microwave ionization and ion detection are used to probe the Rydberg atom motion. We observe guiding of Rydberg atoms over a period of 5 ms following excitation. The decay time of the guided atom signal is about five times that of the initial state. We attribute the lifetime increase to an initial phase of ll-changing collisions and thermally induced Rydberg-Rydberg transitions. Detailed simulations of Rydberg atom guiding reproduce most experimental observations and offer insight into the internal-state evolution

    Pyridine nucleotide metabolism in Escherichia coli. II. Niacin starvation

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    Journal ArticleThe effect of niacin starvation has been studied in a niacin-requiring auxotroph of Escherichia coli. If a culture is totally deprived of niacin, cells continue to divide until the total pyridine nucleotide content has fallen from 1.9 X 10^6 to 1.2 X 10^5 molecules per cell. During starvation, the relative proportion of the pyridine nucleotides changes greatly: the TPN: DPN ratio increases from 0.30 to over 2.0 and nicotinic acid mononucleotide accumulates until it is present at concentrations comparable to DPN

    Pyridine nucleotide metabolism in Escherichia coli. I. Exponential growth

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    Journal ArticleThe pyridine nucleotide pool of Escherichia coli is made up almost exclusively of DPN and TPN. In an exponentially growing glucose culture an average cell contains 1,460,000 molecules of DPN (30% reduced) and 440,000 molecules of TPN (57% reduced). If the total volume of the cell were accessible to pyridine nucleotide, this would mean a total DPN concentration of 1.3 X 10-3 M and a TPN concentration of 3.9 X 10-4 M

    On the jets, kinks, and spheromaks formed by a planar magnetized coaxial gun

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    Measurements of the various plasma configurations produced by a planar magnetized coaxial gun provide insight into the magnetic topology evolution resulting from magnetic helicity injection. Important features of the experiments are a very simple coaxial gun design so that all observed geometrical complexity is due to the intrinsic physical dynamics rather than the source shape and use of a fast multiple-frame digital camera which provides direct imaging of topologically complex shapes and dynamics. Three key experimental findings were obtained: (1) formation of an axial collimated jet [Hsu and Bellan, Mon. Not. R. Astron. Soc. 334, 257 (2002)] that is consistent with a magnetohydrodynamic description of astrophysical jets, (2) identification of the kink instability when this jet satisfies the Kruskal-Shafranov limit, and (3) the nonlinear properties of the kink instability providing a conversion of toroidal to poloidal flux as required for spheromak formation by a coaxial magnetized source [Hsu and Bellan, Phys. Rev. Lett. 90, 215002 (2003)]. A new interpretation is proposed for how the n=1 central column instability provides flux amplification during spheromak formation and sustainment, and it is shown that jet collimation can occur within one rotation of the background poloidal field.Comment: Physics of Plasmas (accepted

    A theory for primary failure of straight centrally loaded columns

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    A theory of primary failure of straight centrally loaded columns is presented. It is assumed that the column cross section and the load are constant throughout the length

    Flavin monooxygenases regulate Caenorhabditis elegans axon guidance and growth cone protrusion with UNC-6/Netrin signaling and Rac GTPases

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    The guidance cue UNC-6/Netrin regulates both attractive and repulsive axon guidance. Our previous work showed that in C. elegans, the attractive UNC-6/Netrin receptor UNC-40/DCC stimulates growth cone protrusion, and that the repulsive receptor, an UNC-5:UNC-40 heterodimer, inhibits growth cone protrusion. We have also shown that inhibition of growth cone protrusion downstream of the UNC-5:UNC-40 repulsive receptor involves Rac GTPases, the Rac GTP exchange factor UNC-73/Trio, and the cytoskeletal regulator UNC-33/CRMP, which mediates Semaphorin-induced growth cone collapse in other systems. The multidomain flavoprotein monooxygenase (FMO) MICAL (Molecule Interacting with CasL) also mediates growth cone collapse in response to Semaphorin by directly oxidizing F-actin, resulting in depolymerization. The C. elegans genome does not encode a multidomain MICAL-like molecule, but does encode five flavin monooxygenases (FMO-1, -2, -3, -4, and 5) and another molecule, EHBP-1, similar to the non-FMO portion of MICAL. Here we show that FMO-1, FMO-4, FMO-5, and EHBP-1 may play a role in UNC-6/Netrin directed repulsive guidance mediated through UNC-40 and UNC-5 receptors. Mutations in fmo-1, fmo-4, fmo-5, and ehbp-1 showed VD/DD axon guidance and branching defects, and variably enhanced unc-40 and unc-5 VD/DD axon guidance defects. Developing growth cones in vivo of fmo-1, fmo-4, fmo-5, and ehbp-1 mutants displayed excessive filopodial protrusion, and transgenic expression of FMO-5 inhibited growth cone protrusion. Mutations suppressed growth cone inhibition caused by activated UNC-40 and UNC-5 signaling, and activated Rac GTPase CED-10 and MIG-2, suggesting that these molecules are required downstream of UNC-6/Netrin receptors and Rac GTPases. From these studies we conclude that FMO-1, FMO-4, FMO-5, and EHBP-1 represent new players downstream of UNC-6/Netrin receptors and Rac GTPases that inhibit growth cone filopodial protrusion in repulsive axon guidance
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