bluuebunny/crossref_metadata_2025 huggingface dataset:
Reconstruction of radial Dirac operators
Authors: Albeverio S. , Hryniv R. , Mykytyuk Ya.
Published: April 2007

We study the inverse spectral problem of reconstructing the potential of radial Dirac operators acting in the unit ball of R3. For each one-dimensional partial Dirac operator corresponding to a nonzero angular momentum, we give a complete description of the spectral data (eigenvalues and suitably defined norming constants), prove existence and uniqueness of solutions to the inverse problem, and present the reconstruction algorithm.
Large-eddy simulation of very large kinetic and magnetic Reynolds number isotropic magnetohydrodynamic turbulence using a spectral subgrid model
Authors: Gomez T. , Sagaut P. , Schilling O. , Zhou Y.
Published: April 2007

A spectral eddy viscosity and magnetic resistivity subgrid-scale model based on the eddy-damped quasi-normal Markovian (EDQNM) kinetic and magnetic energy transfers is used in large-eddy simulation (LES) of asymptotically large kinetic and magnetic Reynolds number magnetohydrodynamic (MHD) turbulence. The model is assessed a posteriori on three-dimensional, incompressible, isotropic, nonhelical, freely decaying MHD turbulence. Using LES initialized with spectra such that the Alfvén ratio of kinetic to magnetic energy equals unity, it is shown that the kinetic energy and magnetic energy spectra exhibit k−5∕3 Kolmogorov inertial subrange scalings consistent with the EDQNM model.
Time-dependent density functional theory Ehrenfest dynamics: Collisions between atomic oxygen and graphite clusters
Authors: Isborn Christine M. , Li Xiaosong , Tully John C.
Published: April 2007

An ab initio direct Ehrenfest dynamics method with time-dependent density functional theory is introduced and applied to collisions of 5eV oxygen atoms and ions with graphite clusters. Collisions at three different sites are simulated. Kinetic energy transfer from the atomic oxygen to graphite local vibrations is observed and electron-nuclear coupling resulting in electronic excitation within the graphite surface as well as alteration of the atomic charge is first reported in this paper. The three oxygen species studied, O(P3), O−(P2), and O+(S4), deposit different amounts of energy to the surface, with the highest degree of damage to the π conjugation of the cluster produced by the atomic oxygen cation. Memory of the initial charge state is not lost as the atom approaches, in contrast to the usual assumption.
Exciton transfer integrals between polymer chains
Authors: Barford William
Published: April 2007

The line-dipole approximation for the evaluation of the exciton transfer integral J between conjugated polymer chains is rigorously justified. Using this approximation, as well as the plane-wave approximation for the exciton center-of-mass wave function, it is shown analytically that J∼L when the chain lengths are smaller than the separation between them, or J∼L−1 when the chain lengths are larger than their separation, where L is the chain length. Scaling relations are also obtained numerically for the more realistic standing wave approximation for the exciton center-of-mass wave function, where it is found that for chain lengths larger than their separation J∼L−1.8 or J∼L−2, for parallel or collinear chains, respectively. These results have important implications for the photophysics of conjugated polymers and self-assembled molecular systems, as the Davydov splitting in aggregates and the Förster transfer rate for exciton migration decrease with chain lengths larger than their separation. This latter result has obvious deleterious consequences for the performance of polymer photovoltaic devices.
A macromolecule in a solvent: Adaptive resolution molecular dynamics simulation
Authors: Praprotnik Matej , Delle Site Luigi , Kremer Kurt
Published: April 2007

The authors report adaptive resolution molecular dynamics simulations of a flexible linear polymer in solution. The solvent, i.e., a liquid of tetrahedral molecules, is represented within a certain radius from the polymer’s center of mass with a high level of detail, while a lower coarse-grained resolution is used for the more distant solvent. The high resolution sphere moves with the polymer and freely exchanges molecules with the low resolution region through a transition regime. The solvent molecules change their resolution and number of degrees of freedom on the fly. The authors show that their approach correctly reproduces the static and dynamic properties of the polymer chain and surrounding solvent.
Transverse transport of solutes between co-flowing pressure-driven streams for microfluidic studies of diffusion/reaction processes
Authors: Salmon Jean-Baptiste , Ajdari Armand
Published: April 2007

We consider a situation commonly encountered in microfluidics: two streams of miscible liquids are brought at a junction to flow side by side within a microchannel, allowing solutes to diffuse from one stream to the other and possibly react. We focus on two model problems: (i) the transverse transport of a single solute from a stream into the adjacent one, (ii) the transport of the product of a diffusion-controlled chemical reaction between solutes originating from the two streams. Our description is made general through a nondimensionalized formulation that incorporates both the parabolic Poiseuille velocity profile along the channel and thermal diffusion in the transverse direction. Numerical analysis over a wide range of the streamwise coordinate x reveal different regimes. Close to the top and the bottom walls of the microchannel, the extent of the diffusive zone follows three distinct power law regimes as x is increased, characterized, respectively, by the exponents 1/2, 1/3, and 1/2. Simple analytical arguments are proposed to account for these results.
Mechanism of subwavelength imaging with bilayered magnetic metamaterials: Theory and experiment
Authors: Sydoruk O. , Shamonin M. , Radkovskaya A. , Zhuromskyy O. , Shamonina E. , Trautner R. , Stevens C. J. , Faulkner G. , Edwards D. J. , Solymar L.
Published: April 2007

We present a theoretical and experimental study of a bilayered metamaterial structure for subwavelength imaging of magnetic field. The simplest version of such a structure consists of one or two linear arrays of capacitively loaded split pipe resonators. Its subwavelength physics is governed by strongly anisotropic magnetic coupling between individual resonators and by propagation of magnetoinductive waves with wavelength much shorter than the wavelength of the electromagnetic radiation in free space. It is shown that magnetoinductive waves propagating in the lateral direction are undesirable because they spread the image. Good subwavelength imaging is achieved when, due to the strong interlayer coupling, a stop band in the vicinity of the resonant frequency appears in the dispersion characteristics. The imaging properties of the single and double lens are compared and it is shown that the double lens has a superior performance. Excellent agreement is obtained between experimental and theoretical results for the magnetic field in the image plane in the operation frequency range of 30–60 MHz. It is shown that the same mechanism is responsible for image formation using bilayered planar metamaterial structures and a design of such a lens comprising two planar layers with a total of 542 elements is provided. The conclusions are not restricted to the radio frequency region because the elements can be scaled down.
Rotation of methyl radicals in a solid argon matrix
Authors: Popov Evgeny , Kiljunen Toni , Kunttu Henrik , Eloranta Jussi
Published: April 2007

Electron spin resonance (ESR) measurements were carried out to study the rotation of methyl radicals (CH3) in a solid argon matrix at 14–35K temperatures. The radicals were produced by dissociating methane by plasma bursts generated either by a focused 193nm laser radiation or a radio frequency discharge device during the gas condensation on the substrate. The ESR spectrum exhibits axial symmetry at the lowest temperature and is ascribed to ground state molecules with symmetric total nuclear spin function I=3∕2. The hyperfine anisotropy (A‖−A⊥) was found to be −0.01mT, whereas that of the g value was 2.5×10−5. The anisotropy is observed for the first time in Ar and is manifested by the splitting of the low-field transition. Elevation of temperature leads reversibly to the appearance of excited state contribution having antisymmetric I=1∕2. As a function of the sample temperature, the relative intensities of symmetric and antisymmetric spin states corresponding to ground and excited rotor states, respectively, proton hyperfine and electron g-tensor components, and spin-lattice relaxation rates were determined by a numerical fitting procedure. The experimental observations were interpreted in terms of a free rotation about the C3 axis and a thermal activation of the C2-type rotations above 15K. The ground and excited rotational state energy levels were found to be separated by 11.2cm−1 and to exhibit significantly different spin-lattice coupling. A crystal field model has been applied to evaluate the energy levels of the hindered rotor in the matrix, and crystal field parameter ϵ4=−200cm−1, corresponding to a 60cm−1 effective potential barrier for rotation of the C3 axis, was obtained.
Matrix formulation of the surface-enhanced Raman optical activity theory
Authors: Bouř Petr
Published: April 2007

The surface-enhanced Raman optical activity theory [J. Chem. Phys.125, 124704 (2006)] is formulated in a matrix form, which makes the formalism simpler and allows to extend it for more complicated colloid and molecular systems.
Subwavelength lasers
Authors: Lawandy Nabil M.
Published: April 2007

Composite media comprised of a host with amplification and high aspect ratio metallic spheroids exhibit a dielectric resonance which is accompanied by both a gigantic index of refraction and large collective gain. Expressions for the complex index of refraction near this dielectric anomaly are derived for the case of oriented spheroids in an amplifying host. The large index of refraction and gain can be used to satisfy the laser cavity resonance condition in nanoscale subwavelength structures with EH11 transverse modes allowing for the future miniaturization of laser devices.
Multiple plasmon resonances from gold nanostructures
Authors: Sheridan A. K. , Clark A. W. , Glidle A. , Cooper J. M. , Cumming D. R. S.
Published: April 2007

Understanding and controlling plasmon resonances from metallic nanoscale structures have been the focus of much attention recently, with applications including local surface plasmon resonance sensing, surface enhanced Raman spectroscopy, and negative refractive index materials. In this letter the authors demonstrate the fabrication of uniform arrays of split rings from gold and show that such structures are capable of supporting multiple plasmon resonances. The authors show that up to five plasmon resonances can be identified and use finite difference time domain modeling and absorption spectroscopy to fully characterize and identify each resonance. The implications of higher order surface plasmon resonances for sensing are discussed.
Electron energy distribution function in plasma determined using numerical simulations of multiple harmonic components on Langmuir probe characteristic—Efficiency of the method
Authors: Jauberteau J. L. , Jauberteau I.
Published: April 2007

The method proposed to determine the electron energy distribution is based on the numerical simulation of the effect induced by a sinusoidal perturbation superimposed to the direct current voltage applied to the probe. The simulation is generating a multiple harmonic components signal over the rough experimental data. Each harmonic component can be isolated by means of finite impulse response filters. Then, the second derivative is deduced from the second harmonic component using the Taylor expansion. The efficiency of the method is proved first on simple cases and second on typical Langmuir probes characteristics recorded in the expansion of a microwave plasma containing argon or nitrogen-hydrogen gas mixture. Results obtained using this method are compared to those, which are determined using a classical Savitzsky–Golay filter.
Developing an optical chopper-modulated capacitive probe for measuring surface charge
Authors: Ugolini D. , McKinney R. , Harry G. M.
Published: April 2007

Gravitational-wave observatories such as Laser Interferometer Gravitational-Wave Observatory (LIGO) use suspended optics in a Michelson interferometer configuration to measure strains in space between 10 Hz and 3 kHz. One potential noise source in this frequency range is the buildup and motion of surface charge on the optics, which can generate fluctuating electric fields, interfere with position control, and reduce reflectance by attracting dust to the optical surface. We have developed a capacitive probe to measure the magnitude and relaxation time of surface charge deposited on smaller test optics in high vacuum (∼10−5 Torr). Our device modulates capacitance with a tuning-fork optical chopper between probe and sample, chosen for vacuum compatibility and minimal cost. We have found that the probe has a resolution of (3.5±0.5)×105 e−∕cm2 in air, on the order of charging levels that could contribute noise to Advanced LIGO, and sufficient for measuring relaxation times on test optics.
Assessing the water challenge of a new green revolution in developing countries
Authors: Rockström Johan , Lannerstad Mats , Falkenmark Malin
Published: April 2007

This article analyzes the water implications in 92 developing countries of first attaining the 2015 hunger target of the United Nations Millennium Development Goals and then feeding a growing population on an acceptable standard diet. The water requirements in terms of vapor flows are quantified, potential water sources are identified, and impacts on agricultural land expansion and water tradeoffs with ecosystems are analyzed. This article quantifies the relative contribution from infiltrated rainwater/green water in rain-fed agriculture, and liquid water/blue water from irrigation, and how far water productivity (WP) gains can go in reducing the pressure on freshwater resources. Under current WP levels, another 2,200 km
3
·yr
−1
of vapor flow is deemed necessary to halve hunger by 2015 and 5,200 km
3
·yr
−1
in 2050 to alleviate hunger. A nonlinear relationship between vapor flow and yield growth, particularly in low-yielding savanna agro-ecosystems, indicates a high potential for WP increase. Such WP gains may reduce additional water needs in agriculture, with 16% in 2015 and 45% by 2050. Despite an optimistic outlook on irrigation development, most of the additional water will originate from rain-fed production. Yield growth, increasing consumptive use on existing rain-fed cropland, and fodder from grazing lands may reduce the additional rain-fed water use further by 43–47% until 2030. To meet remaining water needs, a cropland expansion of ≈0.8% yr
−1
, i.e., a similar rate as over the past 50 years (≈0.65% yr
−1
), seems unavoidable if food production is to occur in proximity to local markets.
Composite synthetic lethal identification of membrane traffic inhibitors
Authors: Duncan Mara C. , Ho David G. , Huang Jing , Jung Michael E. , Payne Gregory S.
Published: April 2007

Small molecule inhibitors provide powerful tools to characterize highly dynamic and complex eukaryotic cell pathways such as those mediating membrane traffic. However, a lack of easy and generalizable assays has constrained identification of novel inhibitors despite availability of diverse chemical libraries. Here, we report a facile growth-based strategy in yeast to screen for pathway-specific inhibitors. The approach uses well characterized synthetic genetic growth defects to guide design of cells genetically sensitized for inhibition of chosen pathways. With this strategy, we identified a family of piperazinyl phenylethanone compounds as inhibitors of traffic between the trans-Golgi network (TGN) and endosomes that depends on the clathrin adaptor complex AP-1. The compounds did not significantly alter other trafficking pathways involving the TGN or endosomes, indicating specificity. Compound treatment also altered localization of AP-1 in mammalian cells. These previously uncharacterized inhibitors will be useful for future studies of clathrin-mediated transport in yeast, and potentially in other organisms. Furthermore, the easily automated technology should be adaptable for identification of inhibitors of other cellular processes.
Cryptic proteolytic activity of dihydrolipoamide dehydrogenase
Authors: Babady Ngolela Esther , Pang Yuan-Ping , Elpeleg Orly , Isaya Grazia
Published: April 2007

The mitochondrial enzyme, dihydrolipoamide dehydrogenase (DLD), is essential for energy metabolism across eukaryotes. Here, conditions known to destabilize the DLD homodimer enabled the mouse, pig, or human enzyme to function as a protease. A catalytic dyad (S456–E431) buried at the homodimer interface was identified. Serine protease inhibitors and an S456A or an E431A point mutation abolished the proteolytic activity, whereas other point mutations at the homodimer interface domain enhanced the proteolytic activity, causing partial or complete loss of DLD activity. In humans, mutations in the DLD homodimer interface have been linked to an atypical form of DLD deficiency. These findings reveal a previously unrecognized mechanism by which certain DLD mutations can simultaneously induce the loss of a primary metabolic activity and the gain of a moonlighting proteolytic activity. The latter could contribute to the metabolic derangement associated with DLD deficiency and represent a target for therapies of this condition.
A feedforward architecture accounts for rapid categorization
Authors: Serre Thomas , Oliva Aude , Poggio Tomaso
Published: April 2007

Primates are remarkably good at recognizing objects. The level of performance of their visual system and its robustness to image degradations still surpasses the best computer vision systems despite decades of engineering effort. In particular, the high accuracy of primates in ultra rapid object categorization and rapid serial visual presentation tasks is remarkable. Given the number of processing stages involved and typical neural latencies, such rapid visual processing is likely to be mostly feedforward. Here we show that a specific implementation of a class of feedforward theories of object recognition (that extend the Hubel and Wiesel simple-to-complex cell hierarchy and account for many anatomical and physiological constraints) can predict the level and the pattern of performance achieved by humans on a rapid masked animal vs. non-animal categorization task.
Raman spectra of a Lower Cambrian ctenophore embryo from southwestern Shaanxi, China
Authors: Chen Jun-Yuan , Schopf J. William , Bottjer David J. , Zhang Chen-Yu , Kudryavtsev Anatoliy B. , Tripathi Abhishek B. , Wang Xiu-Qiang , Yang Yong-Hua , Gao Xiang , Yang Ying
Published: April 2007

The Early Cambrian (≈540 million years old) Meishucun fossil assemblage of Ningqiang County (Shaanxi Province), China, contains the oldest complex skeletonized organisms known in the geological record. We here report the finding in this assemblage of an exquisitely preserved late-stage embryo of a ctenophore (“comb jelly”), its fine structure documented by confocal laser scanning microscopy and shown by Raman spectroscopy to be composed of carbonaceous kerogen permineralized in apatite. In its spheroidal morphology, the presence of eight comb rows and the absence of tentacles, this embryo resembles an adult ctenophore (
Maotianoascus octonarius
) known from the immediately younger Chengjiang fauna of Yunnan, China. The oldest ctenophore and the only embryonic comb jelly known from the fossil record, this exceptionally well preserved specimen provides important clues about the early evolution of the phylum Ctenophora and of metazoans in general.
Rat
Mcs5a
is a compound quantitative trait locus with orthologous human loci that associate with breast cancer risk
Authors: Samuelson David J. , Hesselson Stephanie E. , Aperavich Beth A. , Zan Yunhong , Haag Jill D. , Trentham-Dietz Amy , Hampton John M. , Mau Bob , Chen Kai-Shun , Baynes Caroline , Khaw Kay-Tee , Luben Robert , Perkins Barbara , Shah Mitul , Pharoah Paul D. , Dunning Alison M. , Easton Doug F. , Ponder Bruce A. , Gould Michael N.
Published: April 2007

Breast cancer risk is a polygenic trait. To identify breast cancer modifier alleles that have a high population frequency and low penetrance we used a comparative genomics approach. Quantitative trait loci (QTL) were initially identified by linkage analysis in a rat mammary carcinogenesis model followed by verification in congenic rats carrying the specific QTL allele under study. The
Mcs5a
locus was identified by fine-mapping
Mcs5
in a congenic model. Here we characterize the
Mcs5a
locus, which when homozygous for the Wky allele, reduces mammary cancer risk by 50%. The
Mcs5a
locus is a compound QTL with at least two noncoding interacting elements:
Mcs5a1
and
Mcs5a2
. The resistance phenotype is only observed in rats carrying at least one copy of the Wky allele of each element on the same chromosome.
Mcs5a1
is located within the ubiquitin ligase
Fbxo10
, whereas
Mcs5a2
includes the 5′ portion of
Frmpd1
. Resistant congenic rats show a down-regulation of
Fbxo10
in the thymus and an up-regulation of
Frmpd1
in the spleen. The association of the
Mcs5a1
and
Mcs5a2
human orthologs with breast cancer was tested in two population-based breast cancer case-control studies (≈12,000 women). The minor alleles of rs6476643 (
MCS5A1
) and rs2182317 (
MCS5A2
) were independently associated with breast cancer risk. The minor allele of rs6476643 increases risk, whereas the rs2182317 minor allele decreases risk. Both alleles have a high population frequency and a low penetrance toward breast cancer risk.
Pseudomonas aeruginosa exploits a PIP3-dependent pathway to transform apical into basolateral membrane
Authors: Kierbel Arlinet , Gassama-Diagne Ama , Rocha Claudia , Radoshevich Lilliana , Olson Joan , Mostov Keith , Engel Joanne
Published: April 2007

Pseudomonas aeruginosa, an important human pathogen, preferentially binds and enters injured cells from the basolateral (BL) surface. We previously demonstrated that activation of phosphatidylinositol 3-kinase (PI3K) and Akt are necessary and sufficient for P. aeruginosa entry from the apical (AP) surface and that AP addition of phosphatidylinositol 3,4,5-trisphosphate (PIP3) is sufficient to convert AP into BL membrane (Kierbel, A., A. Gassama-Diagne, K. Mostov, and J.N. Engel. 2005. Mol. Biol. Cell. 16:2577–2585; Gassama-Diagne, A., W. Yu, M. ter Beest, F. Martin-Belmonte, A. Kierbel, J. Engel, and K. Mostov. 2006. Nat. Cell Biol. 8:963–970). We now show that P. aeruginosa subverts this pathway to gain entry from the AP surface. In polarized monolayers, P. aeruginosa binds near cell–cell junctions without compromising them where it activates and recruits PI3K to the AP surface. Membrane protrusions enriched for PIP3 and actin accumulate at the AP surface at the site of bacterial binding. These protrusions lack AP membrane markers and are comprised of BL membrane constituents, which are trafficked there by transcytosis. The end result is that this bacterium transforms AP into BL membrane, creating a local microenvironment that facilitates its colonization and entry into the mucosal barrier.
The role of karyopherins in the regulated sumoylation of septins
Authors: Makhnevych Taras , Ptak Christopher , Lusk C. Patrick , Aitchison John D. , Wozniak Richard W.
Published: April 2007

In the yeast Saccharomyces cerevisiae, several components of the septin ring are sumoylated during anaphase and then abruptly desumoylated at cytokinesis. We show that septin sumoylation is controlled by the interactions of two enzymes of the sumoylation pathway, Siz1p and Ulp1p, with the nuclear transport machinery. The E3 ligase Siz1p is imported into the nucleus by the karyopherin Kap95p during interphase. In M phase, Siz1p is exported from the nucleus by the karyopherin Kap142p/Msn5p and subsequently targeted to the septin ring, where it participates in septin sumoylation. We also show that the accumulation of sumoylated septins during mitosis is dependent on the interactions of the SUMO isopeptidase Ulp1p with Kap121p and Kap95p–Kap60p and the nuclear pore complex (NPC). In addition to sequestering Ulp1 at the NPC, Kap121p is required for targeting Ulp1p to the septin ring during mitosis. We present a model in which Ulp1p is maintained at the NPC during interphase and transiently interacts with the septin ring during mitosis.
Dolichol-linked oligosaccharide selection by the oligosaccharyltransferase in protist and fungal organisms
Authors: Kelleher Daniel J. , Banerjee Sulagna , Cura Anthony J. , Samuelson John , Gilmore Reid
Published: April 2007

The dolichol-linked oligosaccharide Glc3Man9GlcNAc2-PP-Dol is the in vivo donor substrate synthesized by most eukaryotes for asparagine-linked glycosylation. However, many protist organisms assemble dolichol-linked oligosaccharides that lack glucose residues. We have compared donor substrate utilization by the oligosaccharyltransferase (OST) from Trypanosoma cruzi, Entamoeba histolytica, Trichomonas vaginalis, Cryptococcus neoformans, and Saccharomyces cerevisiae using structurally homogeneous dolichol-linked oligosaccharides as well as a heterogeneous dolichol-linked oligosaccharide library. Our results demonstrate that the OST from diverse organisms utilizes the in vivo oligo saccharide donor in preference to certain larger and/or smaller oligosaccharide donors. Steady-state enzyme kinetic experiments reveal that the binding affinity of the tripeptide acceptor for the protist OST complex is influenced by the structure of the oligosaccharide donor. This rudimentary donor substrate selection mechanism has been refined in fungi and vertebrate organisms by the addition of a second, regulatory dolichol-linked oligosaccharide binding site, the presence of which correlates with acquisition of the SWP1/ribophorin II subunit of the OST complex.
Repression of BCL-6 is required for the formation of human memory B cells in vitro
Authors: Kuo Tracy C. , Shaffer Arthur L. , Haddad Joseph , Choi Yong Sung , Staudt Louis M. , Calame Kathryn
Published: April 2007

Memory B cells provide rapid protection to previously encountered antigens; however, how these cells develop from germinal center B cells is not well understood. A previously described in vitro culture system using human tonsillar germinal center B cells was used to study the transcriptional changes that occur during differentiation of human memory B cells. Kinetic studies monitoring the expression levels of several known late B cell transcription factors revealed that BCL-6 is not expressed in memory B cells generated in vitro, and gene expression profiling studies confirmed that BCL-6 is not expressed in these memory B cells. Furthermore, ectopic expression of BCL-6 in human B cell cultures resulted in formation of fewer memory B cells. In addition, the expression profile of in vitro memory B cells showed a unique pattern that includes expression of genes encoding multiple costimulatory molecules and cytokine receptors, antiapoptotic proteins, T cell chemokines, and transcription factors. These studies establish new molecular criteria for defining the memory B cell stage in human B cells.
Improving Data Quality: Actors, Incentives, and Capabilities
Authors: Herrera Yoshiko M. , Kapur Devesh
Published: April 2007

This paper examines the construction and use of data sets in political science. We focus on three interrelated questions: How might we assess data quality? What factors shape data quality? and How can these factors be addressed to improve data quality? We first outline some problems with existing data set quality, including issues of validity, coverage, and accuracy, and we discuss some ways of identifying problems as well as some consequences of data quality problems. The core of the paper addresses the second question by analyzing the incentives and capabilities facing four key actors in a data supply chain: respondents, data collection agencies (including state bureaucracies and private organizations), international organizations, and finally, academic scholars. We conclude by making some suggestions for improving the use and construction of data sets.

It is a capital mistake, Watson, to theorise before you have all the evidence. It biases the judgment.

—Sherlock Holmes in “A Study in Scarlet”

Statistics make officials, and officials make statistics.”

—Chinese proverb
From Sowthistles and Brambles to a More Humanistic Response
Authors: Ames Kenneth J.
Published: April 2007

When Marjorie Nicolson, some thirteen years ago, outlined certain problems facing the teacher of Milton, she was pointing up a trilogy of obstacles that seem today, if anything, even more impenetrable and adamantine than they were when she was writing her helpful little guidebook before the liberating Sixties.1 Now, as then, one confronts the inadequacy of background in fields of particular importance to Milton study (to use Nicolson's divisions): lack of background in the Bible, lack of background in classical mythology, and lack of background in languages. Of course, it is still true, as Nicolson says, that “To know the poetry of John Milton is indeed to have a liberal, a generous, education” (p. xiii), but, sadly, a prior necessity for such a liberal education is a grounding, some kind of primer (or “prerequisite” as we might say now) which in most undergraduates is just not there. It's like the old joke: we'd have some ham and eggs if we had any ham‐but we're all out of eggs!
“With Balanc't Air in Counterpoise”: Milton & Robert Boyle
Authors: Berkowitz M. S.
Published: April 2007

Despite Kester Svendsen's otherwise authoritative study of Milton and science, his statement that Milton's “curiosity in science never advanced to the experiments of a Royal Society nor the speculations of a Descartes or a Hoboes”1 may now require some emendation. The evidence for this assertion appears in Book IV of Paradise Lost in the scene in which Gabriel and Satan stand ready to engage in what promises to be the world's first super‐heavyweight contest:

Th’ Eternal to prevent such horrid fray Hung forth in Heav'n his golden Scales, yet seen Betwixt Astrea and the Scorpion sign, Wherein all things created first he weigh'd, The pendulous round Earth with balanc't Air in counterpoise ……2
Eve's Additions to the Command: Milton and Donne
Authors: Low Anthony
Published: April 2007

Cheryl H. Fresch's informative survey of how various authorities interpreted Eve's modification of the divine prohibition against eating the forbidden fruit (MQ, October, 1978) reveals both that there were several explanations, from which Milton was at liberty to choose one that best suited his purposes, and that what began as a problem–reconciling an apparent conflict in the by‐definition infallible text of Genesis–ended as an opportunity–for moral instruction and literary invention. Another instance of this transformation from exegesis to fabulation, at the hands of a major writer, is to be found in John Donne's sermon “Preached to the Lords upon Easter‐day, at the Communion, The King being then dangerously sick at New‐Market,” on the text “What man is he that liveth, and shall not see death?“
Images of “Licence” in Milton's Sonnet XII
Authors: Wentersdorf Karl P.
Published: April 2007

The publication of the divorce tracts earned for Milton the reputation of a radical whose views favoring the dissolubility of marriage in certain circumstances were in opposition to the basic moral laws of Christian society. Following the appearance of The Doctrine and Discipline of Divorce in 1643, he was attacked as a “lewd” writer guilty of advocating “libertinism” and accused of encouraging men and women to abandon their lawful spouses.1 In the preface to his translation of The Judgment of Martin Bucer (1644), Milton admits that he had been denounced for setting forth a doctrine that was “licentious” and “scandalous.“2 He felt that the opinions of the prestigious Bucer in favor of divorce would strengthen his own position, but the appearance of the translation did little if anything to stem the tide; his writings continued to be criticized as “corrupt and wicked” and “little less than blasphemy.“3 After the simultaneous publication in March 1645 of the Colasterion (a counter‐attack on his opponents) and the Tetrachordon (an account of the four scriptural passages bearing on divorce), the attacks escalated. He was treated as the prophet of a new heretical sect, the Divorcers; his views on loosening the bonds of marriage were said to constitute an incitement to “inordinate lust”; there was even a rumor that Milton had “two or three wives living”; and at the Restoration he was still being castigated as a “Christian libertine.“4
Waiting for Samson: The Modernity of Samson Agonistes
Authors: Freedman Morris
Published: April 2007

Milton himself, of course, insisted on the “ancient” and “Italian,” the “traditional,“ character of Samson Agonistes in his pithy preface to the play with a title reminiscent of Dryden's Essay of Dramatic Poesy: “Of That Sort of Dramatic Poem which is call'd Tragedy.” He also let us know why he bothered to repeat simple if high‐sounding commonplaces about tragedy: “This is mention'd,” he wrote toward the close of his preface, “to vindicate Tragedy from the small esteem, or rather infamy, which in the account of many it undergoes at this day with other common Interludes ……“
Inigo Jones’“Glory” in Poems by Milton and Shirley
Authors: Stevenson Kay
Published: April 2007

For “glory” (sb. 9) as “the circle of light represented as surrounding the head, or the whole figure, of the Saviour, the Virgin, or one of the Saints: an AUREOLE or NIMBUS,“ the OED gives as its earliest citation “1646 Sir T. Browne, Pseud, Ep. v.ix.247 Radiant Halo's … which after the French expression are usually tearmed, the Glory.“
ABSTRACTS
Authors: Cheney Margaret E.
Published: April 2007

The following abstracts are from essays in Milton Studies 25 (1989), ed. James D. Simmonds. Pittsburgh, PA: U of Pittsburgh P, 1990.

Stephen C. Behrendt. “Paradise Lost, History Painting, and Eighteenth‐Century English Nationalism.”

Lloyd F. Dickson. “Against the Wiles of the Devil: Carlotta Petrina's Christocentric Illustrations of Paradise Lost.” 161–90.

Steven C. Dillon. “Milton and the Poetics of Extremism.” 265–83.

M. J. Doherty. “Salvation History, Poetic Form, and the Logic of Time in Milton's Nativity Ode.” 21–42.

J. Karl Franson. “The Fatal Voyage of Edward King, Milton's Lycidas.” 43–67.

John K. Hale. “Milton Playing with Ovid.” 3–19.

Elizabeth Hanson. “To Smite Once and Yet Once More: The Transaction of Milton's Lycidas.” 69–88.

Michael Lieb. “Reading God: Milton and the Anthropopathetic Tradition.” 213–43.

Shirley Sharon‐Zisser. “Silence and Darkness in Paradise Lost.” 191–211.

Keith W. F. Stavely. “Satan and Arminianism in Paradise Lost.” 125–39.

Julia M. Walker. “Milton and Galileo: The Art of Intellectual Canonization.” 109–23.

William Walker. “Typology and Paradise Lost, Books XI and XII.” 245–64.

Robert Wiltenburg. “Damnation in a Roman Dress: Catiline, Catiline, and Paradise Lost.” 89–108.
Tidal Mixing in the Narrows of the Mersey Estuary
Authors: Hughes P.
Published: April 2007

Observations of salinity in the Narrows of the River Mersey have shown that vertical mixing due to tidally induced turbulence may be complete at mid-tide. As tidal currents abate horizontal differential velocities, which constitute a seaward flow in the upper layer and an upriver flow near the bottom, become apparent and produce vertical salinity gradients. A second series of observations showed that vertical homogeneity may not be reached at any stage of the tide if the riverflow is high. Applying the theory for a vertically mixed estuary, coefficients of longitudinal eddy diffusion were computed for a low riverflow of 26 m3/s and gave a mean value of 160 m2/s. During a period of greater fresh water influx (103 m3/s) when conditions were less clearly defined, the average coefficient was considerably higher at 360 m2/s.
Magnetic Cleaning of Rocks in Palaeomagnetic Research
Authors: As J. A. , Zijderveldt J. D. A.
Published: April 2007

It has been observed that the remanent magnetism of rocks is often the resultant of two magnetizations: firstly a magnetization with low coercive force, mostly directed by the local present Earth's field; and secondly a magnetization with high coercive force which shows the direction of the field from the period of the rock formation.

It is shown that it is possible to remove the disturbing magnetization of low coercive force while saving a good deal of the fossil magnetization with the aid of partial demagnetization. This was carried out by a combination of alternating fields and heating.

Generally a demagnetization with alternating fields up to 300 oersted (effective) at a temperature of 150 °C appeared to be sufficient to clean the rocks.
An Investigation into the Calibration of Gravity meters
Authors: Gilbert R. L. G.
Published: April 2007

Gravity observations made with gravity meters over large gravity ranges have shown the instruments to be less satisfactory than is desirable. Figures are given showing the errors which have been found using three gravity meters under various field procedures and some possible causes of error are discussed. The scale constants of the gravity meters are shown to change substantially with time, and a system is described which was built into one gravity meter in order to check the scale constant at any time. The results obtained from this device are tabulated and discussed; no satisfactory mechanism has been produced to explain the change in scale-constant, and the calibration device has some use, although not so much as had been hoped.

It is concluded that for the accurate measurement of large gravity differences careful operation of the gravity meters is essential, the calibration of the instrument being checked regularly; and that pendulum measurements may be preferable for the measurement of very large gravity differences.
An Array Experiment with Magnetic Variometers Near the Coasts of South-east Australia
Authors: Lilley F. E. M. , Bennett D. J.
Published: April 2007

An array of magnetic variometers has been operated in the south-east corner of the Australian mainland, observing the coast effect simultaneously in two dimensions for the first time. The observations are presented as sets of variograms in the time domain and as contour maps of certain parameters in the frequency domain. Vertical field response functions are determined for each station, and the concept of fitting a surface over the area, using the response functions to define tangential planes, is introduced.

By choosing different polarizations of the horizontal fields, the effects of the two coast lines, which are approximately at right angles to one another, can be distinguished. A major result is that for the East Coast, the enhanced vertical variations are not accompanied by significantly enhanced horizontal variations. The distinctive coast effect of the Bass Strait is noted, especially concerning the amplitude of the variations in the horizontal fields. There is a suggestion of an anomalous region in western Victoria, which may correlate with the ‘Newer Volcanics’ rock structure of the area. A quantitative interpretation is planned for a subsequent paper.
Melting on Fault Planes During Large Earthquakes
Authors: McKenzie Dan , Brune James N.
Published: April 2007

For simple models of the movement on a fault during an earthquake the temperature on the fault plane is shown to reach the melting temperature for short periods if the slip is sufficiently large. The displacement required to produce melting depends on the magnitude of the regional stress and also on the friction stress. If both stresses are one kilobar melting can occur for displacements as small as one millimetre. If, however, both stresses are ten bars melting is impossible for any observed displacement. It is estimated that the width of the melted zone could be between 2 mm and 1 cm.

Melting on fault planes during earthquakes is not in disagreement with geological and geophysical observations, and suggests a new explanation for some mylonites. Melting may be important because the molten film rock formed on the fault may act as a lubricant and in the case of large earthquakes allow the release of almost all the elastic strain in the region of the shock. This would provide an important constraint in estimating the state of stress along a fault.
The Influence of Eddy Viscosity on the Vertical Distribution of Velocity in the Tidal Estuary
Authors: McGregor R. C.
Published: April 2007

The periodic equation of motion with a general quadratic form for the eddy viscosity is solved analytically. A logarithmic expression is deduced from this solution which is in better agreement with the accurate solution than previous estimates and allows friction length theory to be put on an analytic footing. With hindsight the approximate solution may be determined directly from the initial data by simple arithmetic.
A Comment on Certain Papers Involving Electromagnetic Induction in Uniformly-Conducting Hemispherical Shells
Authors: Hobbs B. A.
Published: April 2007

It is shown that a series of papers by Rikitake and a paper by Rikitake & Yokoyama, concerning electromagnetic induction in a finitely conducting hemispherical shell, contain solutions that require correction. The solutions are compared to those obtained by Hobbs using an alternative method.
Comparing hard and soft prior bounds in geophysical inverse problems
Authors: Backus George E.
Published: April 2007

In linear inversion of a finite-dimensional data vector y to estimate a finite-dimensional prediction vector z, prior information about the correct earth model x   E is essential if y is to supply useful limits for z. The one exception occurs when all the prediction functionals are linear combinations of the data functionals.

We compare two forms of prior information: a ‘soft’ bound on x   E is a probability distribution px on the model space X which describes the observer's opinion about where x   E is likely to be in X; a ‘hard’ bound on x   E is an inequality QX (x   E , x   E ) 1, where Qx is a positive definite quadratic form on X. A hard bound Qx can be ‘softened’ to many different probability distributions px , but all these px 's carry much new information about x   E which is absent from Qx , and some information which contradicts Qx. For example, all the px 's give very accurate estimates of several other functions of x   E besides Qx (x   E , x   E ). And all the px 's which preserve the rotational symmetry of Qx assign probability 1 to the event Qx (x E , x   E ) =∞. Both stochastic inversion (SI) and Bayesian inference (BI) estimate z from y and a soft prior bound px. If that probability distribution was obtained by softening a hard prior bound Qx , rather than by objective statistical inference independent of y, then px contains so much unsupported new ‘information’ absent from Qx that conclusions about z obtained with SI or BI would seem to be suspect.
A pattern recognition approach to geophysical inversion using neural nets
Authors: Raiche Art
Published: April 2007

This paper is a philosophical exploration of adaptive pattern recognition paradigms for geophysical data inversion, aimed at overcoming many of the problems faced by current inversion methods. APR (adaptive pattern recognition) methods are based upon encoding exemplar patterns in such a way that their features can be used to classify subsequent test patterns. These paradigms are adaptive in that they learn from experience and are capable of inferring rules to deal with incomplete data. APR paradigms can also be highly effective in dealing with noise and other data distortions through the use of exemplars which characterize such distortions. Rather than merely seeking to reduce the point by point mismatch between data and model curves, effective APR paradigms would match patterns by establishing a feature vocabulary and inferring rules to weight the relative importance of these features in interpreting data. They have the advantage that prototype data sets can include analogue modelling data and field survey data rather than being restricted to models for which a numerical forward model can be calculated. The success of this approach to inversion will depend upon the effectiveness of replacing continuous parameter estimation with microclassification (discretized parameter estimation). Once the viability of APR schemes has been established for inverting data from individual geophysical methods, the task of joint interpretation of data from different geophysical survey methods could be accomplished in an optimum fashion by using hierarchical adaptive schemes.

The application of APR to inversion is explored from the standpoint of neural net implementations. The foundations and properties of seven well-known neural net paradigms are examined in terms of several attributes necessary to build an effective inversion system. Different input space representation concepts for feature extraction and data compression are presented, including moment methods and a non-reversible, generalized Fourier transform method. Both parametric and non-parametric concepts for output space representation are explored as microclassification paradigms for quantitative estimation of Earth properties. The paper concludes that neural net paradigms have become sufficiently powerful to justify research programs aimed at implementing APR methods for geophysical inversion.
Immunoglobulin deposition in membranous glomerulonephritis: immunofluorescence and immuno‐election microscopy findings
Authors: DAVIES D. R. , TIGHE J. R. , WING A. J. , JONES N. F.
Published: April 2007

In a series of 250 renal biopsies (transplants excluded) the diagnosis of membranous glomerulonephritis was made in 22. This was done on light microscopy in 17, while the addition of immunofluorescence enabled the diagnosis to be made in a further five. Electron microscopy confirmed the diagnosis in all cases. Immunoperoxidase studies emphasized the basement membrane distribution of the deposits of immunoglobulin and the relative sparing of the mesangium. They showed at an ultrastructural level the presence of IgG in the deposits.
Standardization and the histopathology of tumours
Authors: SOBIN L. H.
Published: April 2007

Standardization of tumour classifications is a prerequisite in facilitating international communication in cancer research. Standardized classifications are not meant to replace, or compete with, conceptual classifications. The World Health Organization's efforts in this field give consideration to definitions of tumour types, terminology, formats of categorization, and codes.
The histological preparation of bronchial brushings–a reliable and satisfactory method
Authors: BLUM L. J. , COLE L. , TOWLER G.
Published: April 2007

A method for improving the diagnostic yield of fibreoptic bronchoscopic bronchial brushings and tiny biopsies has been developed. This technique has proved reliable giving a high positive yield of malignant cells and tissue in the 232 specimens examined.