3,361 research outputs found

    Contact Whiskers for Millimeter Wave Diodes

    Get PDF
    Several techniques are investigated for making short conical tips on wires (whiskers) used for contacting millimeter-wave Schottky diodes. One procedure, using a phosphoric and chromic acid etching solution (PCE), is found to give good results on 12 microns phosphor-bronze wires. Full cone angles of 60 degrees-80 degrees are consistently obtained, compared with the 15 degrees-20 degrees angles obtained with the widely used sodium hydroxide etch. Methods are also described for cleaning, increasing the tip diameter (i.e. blunting), gold plating, and testing the contact resistance of the whiskers. The effects of the whisker tip shape on the electrical resistance, inductance, and capacitance of the whiskers are studied, and examples given for typical sets of parameters

    Pretreatment cognitive and neural differences between sapropterin dihydrochloride responders and non-responders with phenylketonuria

    Get PDF
    Sapropterin dihydrochloride (BH4) reduces phenylalanine (Phe) levels and improves white matter integrity in a subset of individuals with phenylketonuria (PKU) known as “responders.” Although prior research has identified biochemical and genotypic differences between BH4 responders and non-responders, cognitive and neural differences remain largely unexplored. To this end, we compared intelligence and white matter integrity prior to treatment with BH4 in 13 subsequent BH4 responders with PKU, 16 subsequent BH4 non-responders with PKU, and 12 healthy controls. Results indicated poorer intelligence and white matter integrity in non-responders compared to responders prior to treatment. In addition, poorer white matter integrity was associated with greater variability in Phe across the lifetime in non-responders but not in responders. These results underscore the importance of considering PKU as a multi-faceted, multi-dimensional disorder and point to the need for additional research to delineate characteristics that predict response to treatment with BH4

    PROPERTIES OF HOT NUCLEAR MATTER

    No full text
    The properties of cold and hot nuclear matter are studied in the frame of the Brueckner theory, extended to finite temperature. We limit ourself to the BHF approximation. The basic ingredient is the Paris potential supplemented by the introduction of three-body forces coming from the exchange of π and ρ mesons. Particular attention is paid to one-body properties namely the single-particle energy spectrum, the effective mass and the mean free path. We evaluate and discuss the level density parameter a which is closely related to the calculated entropy. In a first approach, the temperature and density dependence of a two-body properties, the effective interaction, is analysed

    The Anglo-Norman Bible's Book of Judges: A Critical Edition (BL Royal 1 C III)

    Get PDF
    A silver-tongued assassin, a motherly prophetess, a consecrated strongman unable to resist the charms of foreign women: the Anglo-Norman Bible’s Book of Judges features a roll-call of unlikely heroes. At the book’s core is a cycle of saviour stories. Twelve times the Israelites embrace foreign gods, succumb to neighbouring enemies, repent and are delivered by a ‘judge’. As Israel itself descends into ever-greater religious, moral and political decay, the narrative pattern also unravels. The book ends bleakly, with stories of rape, murder and civil war. The stage is set for a king. Gideon-a doubting Thomas who repeatedly ‘tests’ God-and Samson-lion-killer and lover of Delilah-were firm medieval favourites. Their tales and those of other flawed judges inspired heroic deeds on the battlefield and provided lessons on how to behave (and indeed how not to behave). With its remarkable heroines, moreover-from cut-throat Jael, who wields a tent-peg to devastating effect, to Jephthah’s dignified daughter, sacrificed because of her father’s rash vow-this is a book that prompted much reflection in the Middle Ages on the place of women in society. The Anglo-Norman Bible’s Book of Judges survives in two fourteenth-century manuscripts: British Library Royal MS 1 C III (L), noted for its multilingual glosses, and the richly illustrated Paris, Bibliothèque nationale de France, fonds français 1 (P). The critical text, based on L, has been prepared by Pitts. An introduction and notes by Grange aim to elucidate and interpret the Anglo-Norman Bible’s Book of Judges for the modern reader

    The Commission and Its Report: Public Education, Advocacy and Lobbying

    Get PDF
    Mr. Harris: The question concerning the justification of commissions of inquiry has been raised in the preceding discussions. If their sole justification is having the bulk of their recommendations implemented, the institution probably would have died out long ago. Nevertheless, it must be of considerable concern to commissioners that the record has not been good in terms of implementation and one of the questions that perhaps will determine how successful commissions are in this respect has to do with what happens when the report is delivered and thereafter. These questions will be largely the subject of the panel that we are about to present. You will not be treated to profound, scholarly papers on policy analysis or anything like that in this panel. There will be practical comments and suggestions

    Estimating turbulent velocities in the elliptical galaxies NGC 5044 and NGC 5813

    Full text link
    The interstellar and intra-cluster medium in giant elliptical galaxies and clusters of galaxies is often assumed to be in hydrostatic equilibrium. Numerical simulations, however, show that about 5-30% of the pressure in a cluster is provided by turbulence induced by, for example, the central AGN and merger activity. We aim to put constraints on the turbulent velocities and turbulent pressure in the ICM of the giant elliptical galaxies NGC 5044 and NGC 5813 using XMM-Newton RGS observations. The magnitude of the turbulence is estimated using the Fe XVII lines at 15.01 A, 17.05 A, and 17.10 A in the RGS spectra. At low turbulent velocities, the gas becomes optically thick in the 15.01 A line due to resonant scattering, while the 17 A lines remain optically thin. By comparing the (I(17.05)+I(17.10))/I(15.01) line ratio from RGS with simulated line ratios for different Mach numbers, the level of turbulence is constrained. The measurement is limited by systematic uncertainties in the atomic data, which are at the 20-30% level. We find that the line ratio in NGC 5813 is significantly higher than in NGC 5044. This difference can be explained by a higher level of turbulence in NGC 5044. The high turbulent velocities and the fraction of the turbulent pressure support of >40% in NGC 5044, assuming isotropic turbulence, confirm that it is a highly disturbed system, probably due to an off-axis merger. The turbulent pressure support in NGC 5813 is more modest at 15-45%. The (I(17.05)+I(17.10))/I(15.01) line ratio in an optically thin plasma, calculated using AtomDB v2.0.1, is 2 sigma above the ratio measured in NGC 5044, which cannot be explained by resonant scattering. This shows that the discrepancies between theoretical, laboratory, and astrophysical data on Fe XVII lines need to be reduced to improve the accuracy of the determination of turbulent velocities using resonant scattering.Comment: 11 pages, 5 figures, accepted for publication in A&

    Cavity-Enhanced Two-Photon Interference using Remote Quantum Dot Sources

    Full text link
    Quantum dots in cavities have been shown to be very bright sources of indistinguishable single photons. Yet the quantum interference between two bright quantum dot sources, a critical step for photon based quantum computation, has never been investigated. Here we report on such a measurement, taking advantage of a deterministic fabrication of the devices. We show that cavity quantum electrodynamics can efficiently improve the quantum interference between remote quantum dot sources: poorly indistinguishable photons can still interfere with good contrast with high quality photons emitted by a source in the strong Purcell regime. Our measurements and calculations show that cavity quantum electrodynamics is a powerful tool for interconnecting several devices.Comment: 5 pages, 4 figures (Supp. Mat. attached

    Constraining the Flux of Impactors Postdating Heavy Bombardment Using U-Pb Ages of Impact Glasses

    Get PDF
    Spherules of glass varying in size from a few micrometres to a few millimetres are common in the lunar regolith. While some of these glass beads are products of pyroclastic fire fountains others originate as impact melt ejected from the target that breaks into small droplets and solidifies as spherical particles while raining back to the lunar surface. These glasses preserve information about the chemical composition of the target and often contain sufficient amount of radioactive nuclides such as 40K to enable Ar-40-Ar-39 dating of individual beads. Studies measuring the age of glass beads have been used in attempts to establish variations in the flux of impactors hitting the Moon, particularly during the period that postdates the formation of major impact basins [1,2]. These studies proposed a possibility of spike in the impact flux about 800 Ma [2] and over the last 400 Ma [1]. More recently U-Th-Pb isotopic systems have been also utilized to determine the age of impact glasses from the Apollo 17 regolith [3]. Our aim is to extend the application of the U-Pb system in impact glasses to spherules isolated from Apollo 14 soil 14163 in an attempt to further investigate the applicability of this isotopic system to the chronology of impact glass beads and gain additional information on the impact flux in the inner Solar system
    corecore