bluuebunny/crossref_metadata_2025 huggingface dataset:
Malthusian Models and Irish History
Authors: Mokyr Joel
Published: May 2010

Malthusian models occupy a central position in the interpretation and analysis of long-term economic and demographic change in preindustrial societies. The models are logically plausible and attractive, but ultimately they will have to be confronted with systematic evidence before being accepted. In this paper results are reported that cast some doubt on these models in the case of prefamine Ireland. The results indicate that the evidence supporting Malthusian views is not strong, and that the modus operandi of the nexus between economic and demographic variables is probably far more complex than is implied in standard Malthusian models.
American Entrepreneurs and the Horatio Alger Myth
Authors: Sarachek Bernard
Published: May 2010

Since 1925 a number of scholars have conducted studies of the general business elite in America. Their studies have concluded that the American business elite has been predominantly native born, urban, better educated than the general population, and has originated disproportionately from higher economic classes. These conclusions are not surprising. It might have been surprising if the business elite were found to have emerged predominantly from the poor and less educated, and the immigrant, farm or working-class populations. Such origins would infer a rapid displacement of elite members, the possibility of rapid and massive disaggregation of family fortunes, and the loss of family aggrandizement as a motivating consideration in the minds of aspiring businessmen. This, however, was apparently not the case.
The Regional Diffusion and Adoption of the Steam Engine in American Manufacturing
Authors: Atack Jeremy , Bateman Fred , Weiss Thomas
Published: May 2010

In spite of the importance accorded the steam engine during nineteenth-century industrialization, little is known about its rate of diffusion and the determinants thereof in the United States. The primary purpose of this paper is to enhance our knowledge about the spread of this technology. New evidence on steam power use in 1820, 1850, and 1860, combined with published census data from 1870, permits quantitative estimates of the regional variations in timing, pace, and extent of usage before 1900. Second, we advance reasonable conjectures for the regional differences that appear. Although lack of evidence precludes a definitive delineation of causality, with simulation techniques we are able to use the limited evidence available on costs to reconcile, albeit imperfectly, the historical pattern with economic-theoretic predictions regarding the process of innovation.
Inflation or Deflation in Nineteenth-Century Syria and Palestine
Authors: Gerber Haim , Gross Nacham T.
Published: May 2010

From the 1830s on Syria and Palestine exported monetary metal to pay for an import surplus. Nevertheless, there is evidence of a concomitant inflationary process. The apparent contradiction is resolved by a theoretical argument and by reference to the dual nature of the Ottoman monetary system. Government-induced inflation in terms of the domestic (token and paper) money reinforced the rising price of full-bodied coins, caused by the adverse balance of trade.
Sound generation by turbulent boundary-layer flow over small steps
Authors: JI MINSUK , WANG MENG
Published: May 2010

The aeroacoustics of low-Mach-number boundary-layer flow over backward and forward facing steps is studied using large-eddy simulation and Lighthill's theory. The Reynolds number based on the step height and free-stream velocity ranges from 21000 to 328 as the step height is varied from 53% to 0.83% of the unperturbed boundary layer thickness at the step. For the largest step size, statistics of wall pressure fluctuations such as the root mean square values and frequency spectral density yield favourable comparisons with available experimental measurements. A low-frequency Green's function for the step geometry, valid for an acoustically compact step height, is employed to evaluate the volume integral in the solution to Lighthill's equation. Consistent with the result of previous theoretical studies, the steps act primarily as a dipole source aligned in the streamwise direction. The sound from the forward step is shown to be significantly louder than that from the backward step and the underlying reason is analysed in terms of source strength and distribution relative to the Green's function. The forward step generates stronger sources in regions closer to the step corner, which is heavily weighted by the Green's function. A detailed analysis of flow field and Green's function weighted sources reveals that the backward step generates sound mainly through a diffraction mechanism, while the forward step generates sound through a combination of diffraction and turbulence modification by the step. As the step height decreases, the difference in noise level between forward and backward steps is much reduced as turbulence modification becomes less significant.
Homogeneity of turbulence generated by static-grid structures
Authors: ERTUNÇ Ö. , ÖZYILMAZ N. , LIENHART H. , DURST F. , BERONOV K.
Published: May 2010

Homogeneity of turbulence generated by static grids is investigated with the help of hot-wire measurements in a wind-tunnel and direct numerical simulations based on the Lattice Bolztmann method. It is shown experimentally that Reynolds stresses and their anisotropy do not become homogeneous downstream of the grid, independent of the mesh Reynolds number for a grid porosity of 64%, which is higher than the lowest porosities suggested in the literature to realize homogeneous turbulence downstream of the grid. In order to validate the experimental observations and elucidate possible reasons for the inhomogeneity, direct numerical simulations have been performed over a wide range of grid porosity at a constant mesh Reynolds number. It is found from the simulations that the turbulence wake behind the symmetric grids is only homogeneous in its mean velocity but is inhomogeneous when turbulence quantities are considered, whereas the mean velocity field becomes inhomogeneous in the wake of a slightly non-uniform grid. The simulations are further analysed by evaluating the terms in the transport equation of the kinetic energy of turbulence to provide an explanation for the persistence of the inhomogeneity of Reynolds stresses far downstream of the grid. It is shown that the early homogenization of the mean velocity field hinders the homogenization of the turbulence field.
Gesture and posture: pointing the finger and the mapping of outer continental shelves
Authors: Dodds Klaus
Published: May 2010

This note considers the practice of pointing the finger at the map. Using two recent examples from Australia and Norway involving outer continental shelf submissions, it considers why such a bodily gesture might actually be more than a mere gesture. With regard to the polar regions, it is a timely reminder that ceremonies of possession remain important and provides further opportunity to reflect on the embodied and gendered nature of these activities. Being seen is one thing and being cited is another.
THE HOMELESS OBSERVER: JOHN HARSANYI ON INTERPERSONAL UTILITY COMPARISONS AND BARGAINING, 1950–1964
Authors: FONTAINE PHILIPPE
Published: May 2010

This paper traces interpersonal utility comparisons and bargaining in the work of John Harsanyi from the 1950s to the mid-1960s. As his preoccupation with how theorists can obtain information about agents moved from an approach centered on empathetic understanding to the more distanced perspective associated with game theory, Harsanyi shifted emphasis from the social scientist’s lack of information vis-à-vis agents to agents’ lack of information about each other. In the process, he provided economists with an analytical framework they could use to study problems related to the distribution of information among agents while consolidating the perspective of a distant observer whose knowledge can replace that of real people.
Introduction to the TPLP special issue, logic programming in databases: From Datalog to semantic-web rules
Authors: ORSI GIORGIO , TANCA LETIZIA
Published: May 2010

Much has happened in data and knowledge base research since the introduction of the relational model in Codd (1970) and its strong logical foundations influence its advances ever since. Logic has been a common ground where Database and Artificial Intelligence research competed and collaborated with each other for a long time (Abiteboul et al. 1995). The product of this joint effort has been a set of logic-based formalisms, such as the Relational Calculus (Codd 1970), Datalog (Ceri et al. 1990), Description Logics (Baader et al. 2007), etc., capturing not only the structure but also the semantics of data in an explicit way, thus enabling complex inference procedures.
Contact surgeries and the transverse invariant in knot Floer homology
Authors: Ozsváth Peter , Stipsicz András I.
Published: May 2010

We study naturality properties of the transverse invariant in knot Floer homology under contact (+1)-surgery. This can be used as a calculational tool for the transverse invariant. As a consequence, we show that the Eliashberg–Chekanov twist knots En are not transversely simple for n odd and n > 3.
Swan conductors for p-adic differential modules. II Global variation
Authors: Kedlaya Kiran S.
Published: May 2010

Using a local construction from a previous paper, we exhibit a numerical invariant, the differential Swan conductor, for an isocrystal on a variety over a perfect field of positive characteristic overconvergent along a boundary divisor; this leads to an analogous construction for certain p-adic and l-adic representations of the étale fundamental group of a variety. We then demonstrate some variational properties of this definition for overconvergent isocrystals, paying special attention to the case of surfaces.
SUPER LIARS
Authors: SCHLENKER PHILIPPE
Published: May 2010

Kripke’s theory of truth offered a trivalent semantics for a language which, like English, contains a truth predicate and means of self-reference; but it did so by severely restricting the expressive power of the logic. In Kripke’s analysis, the Liar (e.g.,This very sentence is not true) receives the indeterminate truth value, but this fact cannot be expressed in the language; by contrast, it is straightforward to say in English thatthe Liar is something other than true. Kripke’s theory also fails to handle the Strengthened Liar, which can be expressed in English as:This very sentence is something other than true. We develop a theory which seeks to overcome these difficulties, and is based on a detailed analysis of some of the linguistic means by which the Strengthened Liar can be expressed in English. In particular, we propose to takeliterallythe quantificational form of the negative expressionsomething other than true.Like other quantifiers, it may have different implicit domain restrictions, which give rise to a variety of negations of different strengths (e.g.,something other than true among the values{0, 1}, oramong{0, 1, 2}, etc). This analysis naturally leads to a logic with as many truth values as there are ordinals—a conclusion reached independently by Cook (2008a). We develop the theory within a generalization of the Strong Kleene Logic, augmented with negations that each have a nonmonotonic semantics. We show that fixed points can be constructed for our logic, and that it enjoys a limited form of ‘expressive completeness’. Finally, we discuss the relation between our theory and various alternatives, including one in which the wordtrue(rather than negation) is semantically ambiguous, and gives rise to a hierarchy of truth predicates of increasing strength.
Infrapopliteal run-off and the outcome of femoropopliteal percutaneous transluminal angioplasty
Authors: Salapura  , Blinc  , Kozak  , Jezovnik  , Pohar Perme  , Berden  , Kuhelj  , Kljucevsek  , Popovic;  , Stankovic  , Vrtovec  , Surlan
Published: May 2010

Background: The outcome of percutaneous transluminal angioplasty (PTA) of peripheral arterial lesions is influenced by several factors, including the haemodynamic conditions. Our study tested: (a) whether infrapopliteal run-off after completed PTA influenced the time course of restenosis/reocclusion of the femoropopliteal arterial segment, and (b) whether worsening of infrapopliteal run-off influenced the long-term femoropopliteal patency after PTA. Patients and methods: Among 245 patients treated by femoropopliteal PTA we enroled 176 patients who consented to regular follow-up. Concomitant infrapopliteal PTA was performed whenever feasible. The technical success of PTA and the patency of calf arteries were assessed by angiography. Infrapopliteal run-off was scored by a modification of the Society for Vascular Surgery criteria. The treated patients' limbs were divided into a group with good infrapopliteal run-off and a group with compromised run-off. Follow-up examination of the femoropopliteal arterial segment was performed by vascular ultrasonography (US) 1, 6 and 12 months after PTA, and an adverse outcome was defined by a ≥ 50 % stenosis, i.e., at least doubling of the maximal systolic velocity, or occlusion - evidenced by the absence of flow. The patency of calf arteries was re-assessed by US 12 months after PTA. Results: One month after femoropopliteal PTA 19 / 83 (23 %) of patients with compromised run-off developed the combined end-point of restenosis or reocclusion in comparison to 10 / 93 (11 %) with good run-off (p = 0.03). After 6 months the incidence of restenosis/reocclusion had increased in both groups at an approximately equal rate, but the differences were no longer significant: 39 / 80 (49 %) in the compromised run-off group vs. 36 / 83 (43 %) in the good run-off group after 6 months, p = 0.49, and 42 / 73 (57 %) vs. 38 / 73 (52 %) after 12 months, p = 0.51. However, in patients' limbs with good periprocedural run-off that deteriorated into compromised run-off in the year after PTA, femoropopliteal restenosis/reocclusion occurred more often than in limbs which retained good run-off: 10 / 14 (71 %) vs. 18 / 51 (35 %), p = 0.02. Conclusions: Compromised postprocedural infrapopliteal run-off predisposes to early restenosis/reocclusion after femoropopliteal PTA. Deterioration of infrapopliteal run-off in the year after femoropopliteal PTA is accompanied by worsening of long-term femoropopliteal patency.
Vibrational kinetics of air plasmas induced by sprites
Authors: Gordillo‐Vazquez F. J.
Published: May 2010

The vibrational kinetics of air plasmas produced by the presence of sprites in the mesosphere of the Earth is studied in detail. The present model solves the coupled electron Boltzmann equation and rate equations for electrons, neutrals (ground and excited), and ions. Special attention is paid to the vibrational kinetics of N2 (X1Σg+) and to that of the N2 triplet states (A3Σu+, B3Πg, C3Πu, W3Δu, and B′3Σu+). The results presented are for an altitude of 78 km over sea level where the model‐predicted vibrational distribution function (VDF) of N2 (B3Πg) is in agreement with available VDF derived from sprite spectra (640–820 nm) obtained using spectrographs coupled to high‐speed video cameras (300 frames per second (fps)). In addition, the model predictions indicate that the sprite plasma VDFs of N2 (B3Πg) and N2 (C3Πu) are almost in thermal equilibrium and exhibit a maximum at v = 0 followed by lower values for v = 1 and v = 2. Finally, it is also predicted that the N2 (B3Πg) and N2 (C3Πu) VDFs recorded with very high speed video cameras (up to 10000 fps) should not differ much from the N2 (B3Πg) and N2 (C3Πu) VDFs obtained with cameras working at lower speeds (30 and 300 fps).
Airborne synthetic aperture radar observations of “spiral eddy” slick patterns in the Southern California Bight
Authors: Marmorino George O. , Holt Benjamin , Molemaker M. Jeroen , DiGiacomo Paul M. , Sletten Mark A.
Published: May 2010

Repeat sampling on hourly time scales using an airborne synthetic aperture radar (SAR) is used to investigate the occurrence and evolving characteristics of spiral‐shaped slick patterns, commonly presumed to be indicators of submesoscale ocean eddies, in the area around Santa Catalina Island, California (∼33.4°N, 118.4°W). Simultaneous SAR imagery and boat survey data are examined over two ∼5 h long periods spaced 3 days apart in April 2003. The SAR imagery reveals several spiral‐like patterns, roughly 5 km in diameter, occurring downstream of the western end of Catalina. We believe that the most likely formation mechanism for these patterns is current‐wake instability related to the flow of the Southern California Countercurrent along the north shore of Catalina. In one case, there is an observed cold‐core eddy and vortex sheet attached to the tip of the island, similar to island‐wake simulations done by Dong and McWilliams (2007). In another case, the SAR imagery shows a series of slick patterns that, at least initially, resemble spiral eddies, but the data show no clear evidence of actual ocean eddies being present either at depth or through a rotating surface expression. A speculation is that such features signify island‐wake eddies that are relatively weak and dissipate quickly. An unexpected finding was how quickly a spiral slick pattern could deteriorate, suggesting a time scale for the surface feature of the order of only several hours. An implication of this result is that care is needed when interpreting a single satellite SAR imagery for evidence of active submesoscale eddies. Recommendations are made for future field studies.
Seismic characteristics around the fault segment boundary of historical great earthquakes along the Nankai Trough revealed by repeated long‐term OBS observations
Authors: Mochizuki Kimihiro , Nakahigashi Kazuo , Kuwano Asako , Yamada Tomoaki , Shinohara Masanao , Sakai Shin'ichi , Kanazawa Toshihiko , Uehira Kenji , Shimizu Hiroshi
Published: May 2010

The existence of a static fault segment boundary has been proposed for segmentation of the historical great earthquakes along the Nankai Trough, southwest of Japan. Due to the extremely low seismicity, the seismic characteristics around the boundary have remained too uncertain to allow detailed discussion of the cause of the fault segmentation. We collected four years of continuous seismic data around the segment boundary through repeated marine observations and determined accurate hypocenters, magnitudes and focal mechanisms of the observed earthquakes. The Tokai segment to the east of the boundary shows particularly low seismicity. An abrupt change in the P‐axis orientation of intra‐slab earthquakes coincides with heterogeneous structure within the subducting Philippine Sea Plate. The boundaries between regions of different seismic character are parallel to the magnetic anomaly lineation over the Shikoku Basin of the subducting plate, implying that they are determined by the formation process of the basin.
Innovative bioinformatic approaches for developing peptide‐based vaccines against hypervariable viruses
Authors: Sirskyj Danylo , Diaz‐Mitoma Francisco , Golshani Ashkan , Kumar Ashok , Azizi Ali
Published: May 2010

The application of the fields of pharmacogenomics and pharmacogenetics to vaccine design has been recently labeled ‘vaccinomics’. This newly named area of vaccine research, heavily intertwined with bioinformatics, seems to be leading the charge in developing novel vaccines for currently unmet medical needs against hypervariable viruses such as human immunodeficiency virus (HIV), hepatitis C and emerging avian and swine influenza. Some of the more recent bioinformatic approaches in the area of vaccine research include the use of epitope determination and prediction algorithms for exploring the use of peptide epitopes as vaccine immunogens. This paper briefly discusses and explores some current uses of bioinformatics in vaccine design toward the pursuit of peptide vaccines for hypervariable viruses. The various informatics and vaccine design strategies attempted by other groups toward hypervariable viruses will also be briefly examined, along with the strategy used by our group in the design and synthesis of peptide immunogens for candidate HIV and influenza vaccines.
Re-evaluating the list of high-production chemicals predicted to become Arctic contaminants
Authors: Rayne Sierra , Forest Kaya
Published: May 2010

The large number of historical and current organic chemicals in commerce, and the ability of these compounds to make their way from industrial to remote regions, has resulted in concerted efforts to predict which chemicals have the capacity to migrate from where they are used/disposed to areas such as the Arctic. A suite of 120 high production volume chemicals has been recently screened from an initial dataset of >100,000 compounds and listed as potential Arctic contaminants. In the current work, we critically assess members of this proposed list for their possible rapid reactivity in environmental systems that would prevent substantial accumulation or transport in the environment and accumulation in vivo, as well as whether the investigated physicochemical properties are adequate for the intended environmental screening purposes.
Allergological and toxicological risk assessment of genetically modified (GM) plants - Development of a model system
Authors: Steinmann Alain , Entzian Kristin , Grümmer Birgit , Meyer Udo
Published: May 2010

Technical advances in biotechnology lead to a rising number of genetically modified plants and derived food and feed. Therefore, the international interest in adequate and standardized analytical methods increases to assess health risks in a rapid and low cost manner.To address this issue a decision support system (DSS), which will be based on baseline data and thresholds of key parameters, is going to be established in the framework of a joint project (BioOK). Determination of the potential allergenicity or toxicity of novel proteins caused by the genetic modification compared to near isogenic variants (NIV) is a key issue in this context. For the development of DSS the model plant “potato” was used to compare values of relevant parameters of GM plants with those of NIV using different allergological and toxicological methods which are shown in the present poster. No significant differences in comparison of the results of GM plants and NIV were found so far.
Development of a sampling regime for research with environmental relevance based on variability of transgene expression in plants
Authors: Struzyna-Schulze Carla , Mikschofsky Heike , Mönkemeyer Wenke , Schmidtke Jörg , Schmidt Kerstin , Broer Inge
Published: May 2010

Transgenic plants often produce proteins that are unknown in conventional crops. Therefore, it requires a fundamental analysis before approval of a new genetically modified plant is given. Since the EFSA-guidelines for risk assessment on transgenic plants provide only recommendations but no detailed instructions, we wanted to develop a valid test scheme that defines sample size and sampling organ to enable a statically valid and efficient analysis of transgene expression and its variability. The scheme will be based on data obtained for the variability in expression i. of different recombinant proteins in one variety; ii. of different integration sites of one transgene in one variety; iii. of the same recombinant protein between different varieties and between isogenic clones in a variety. The optimization of experimental procedures shall enable the development of cost and time efficient and valid sampling systems that will be used as a part of the Decision Support System (DSS) that is developed by BioOK.
Detection strategies for non-authorized GMO products on the European market
Authors: Gürtler Patrick , Meissner Esther , Busch Ulrich
Published: May 2010

Import and planting of biotech crops is strictly regulated in Europe. In order to observe these strict regulations, an efficient surveillance of the European market is required. In Europe, data on authorised biotech crops from foreign countries are on hand, however, only scarce information on non-authorised biotech crops is available. Experience of the last years has shown that non-authorized biotech crops (e.g. biotech-papaya, Bt10-maize, LL601-rice and Bt63-rice) were detected on the European market. The Bavarian Health and Food Safety Authority is responsible for the detection of illegal imports and for labelling control of Food and Feed in Bavaria (Germany). The quantitative real-time PCR is the method of choice for the detection of genetic modifications in plants on DNA level. Therefore, data on novel DNA constructs and event-specific detection methods need to be gathered to assure the surveillance of the market for non-authorised GMO.
The Viscosity and Thermal Conductivity Coefficients of Dilute Nitrogen and Oxygen
Authors: Hanley H. J. M. , Ely James F.
Published: May 2010

The viscosity and thermal conductivity coefficients of dilute oxygen and nitrogen are discussed and tables of values are presented for temperatures between 80 and 2000 K. The oxygen viscosity tables are estimated to be accurate to two percent for temperatures up to 400 K and four percent above that temperature; the nitrogen viscosity tables are estimated to be reliable to one percent in the range 100–1000 K, increasing to two percent above 1000 K and below 100 K. The error assigned to the thermal conductivity is three percent below 400 K and five percent above 400 K for both gases. The tables were calculated from the appropriate kinetic theory equations using the m-6–8 model potential with nonspherical contributions. The approximations to the equations are discussed. It is emphasized that the available data for oxygen viscosity are generally poor and that the thermal conductivity data for both oxygen and nitrogen cannot be considered reliable at high temperatures. No oxygen data exist for temperatures above 1500 K.
Thermodynamic Properties of Nitrogen Including Liquid and Vapor Phases from 63 K to 2000 K with Pressures to 10,000 Bar
Authors: Jacobsen Richard T. , Stewart Richard B.
Published: May 2010

Tables of thermodynamic properties of nitrogen are presented for the liquid and vapor phases for temperatures from the freezing line to 2000 K and pressures to 10,000 bar. The tables include values of density, internal energy, enthalpy, entropy, isochoric heat capacity (Cv), isobaric heat capacity (Cp), velocity of sound, the isotherm derivative (∂P/∂ρ)τ, and the isochor derivative (∂P/∂T)ρ. The thermodynamic property tables are based on an equation of state, P=P (ρ,T), which accurately represents liquid and gaseous nitrogen for the range of pressures and temperatures covered by the tables. Comparisons of property values calculated from the equation of state with measured values for P-ρ-T, heat capacity, enthalpy, latent heat, and velocity of sound are included to illustrate the agreement between the experimental data and the tables of properties presented here. The coefficients of the equation of state were determined by a weighted least squares fit to selected P-ρ-T data and, simultaneously, to Cv data determined by corresponding states analysis from oxygen data, and to data which define the phase equilibrium criteria for the saturated liquid and the saturated vapor. The vapor pressure equation, melting curve equation, and an equation to represent the ideal gas heat capacity are also presented. Estimates of the accuracy of the equation of state, the vapor pressure equation, and the ideal gas heat capacity equation are given. The equation of state, derivatives of the equation, and the integral functions for calculating derived thermodynamic properties are included.
Thermodynamic Properties of Helium 4 from 2 to 1500 K at Pressures to 108 Pa
Authors: Mc Carty Robert D.
Published: May 2010

Tabular values of density, internal energy, enthalpy, entropy, heat capacity, and speed of sound for liquid and gaseous helium are presented for temperatures from 2 to 1500 kelvin at pressures from 1.0 × 104 to 1.0 × 108 pascals. Diagrams of temperature vs entropy are also given. The properties presented are calculated from an equation of state which was fitted to experimental P—V—T and other thermodynamic data from the world's literature. The equation of state was fitted to these data in three separate regions of pressure and temperature. The regional equations are forced to join smoothly at the preconceived boundaries. Extensive comparisons between the equation of state and experimental data have been made, and deviation plots are presented. A particularly careful determination of the second virial coefficient over the full temperature range 2–1500 kelvin is presented. The Joule-Thomson inversion curve has been calculated and comparisons made with other sources. Equations for the density of the saturated liquid and vapor are included as well as an equation which represents the 1958 helium vapor pressure temperature scale.
Identifying unstable modes in stratified shear layers
Authors: Carpenter J. R. , Balmforth N. J. , Lawrence G. A.
Published: May 2010

One interpretation of the mechanism of instability in stratified shear flows is based on the idea that two independently propagating waves may interact to cause mutual growth in one another. This theory is used in the present study to develop a diagnostic that can be used to identify different types of unstable modes. We focus on stratified shear layers that are susceptible to both the Kelvin–Helmholtz (KH) and Holmboe (H) modes of instability—though the formulation is more general. The diagnostic is found to be useful in differentiating between KH and H modes in the symmetric stratified shear layer (where the center of the shear layer and the density interface coincide). The asymmetric stratified shear layer is also examined since there is no clear distinction between KH- and H-type modes in this flow. The KH mechanism of growth is predicted to extend to stronger stratifications (i.e., larger bulk Richardson numbers) than in the symmetric case, in qualitative agreement with nonlinear numerical results. However, the transition is found to be a gradual one in which the KH mechanism gives way to the H as the bulk Richardson number is increased. In order to demonstrate the utility of the method, we apply it to instability observed in the Fraser River estuary.
Theoretical study of the X Σ2+ states of the neutral CM–RG complexes (CM=coinage metal, Cu, Ag, and Au and RG=rare gas, He–Rn)
Authors: Gardner Adrian M. , Plowright Richard J. , Watkins Mark J. , Wright Timothy G. , Breckenridge W. H.
Published: May 2010

We present high level ab initio potential energy curves for the X Σ2+ electronic states of the CM–RG complexes; where CM is a coinage metal, CM=Cu, Ag and Au and RG is a rare gas, RG=He–Rn. These potentials are calculated over a range of internuclear separations, R, and the energy at each point is corrected for basis set superposition error and extrapolated to the basis set limit. Spectroscopic constants are determined from the potentials so obtained and are compared to available experimental data. The impact of core-valence correlation to the overall interactions within the complexes involving the lighter RG atoms is also considered. We find that there is a surprising continuous decrease in Re in these species from CM-He to CM-Rn and show that this is likely due to a combination of sp hybridization and small amounts of charge transfer.
Plastic ablator ignition capsule design for the National Ignition Facility
Authors: Clark Daniel S. , Haan Steven W. , Hammel Bruce A. , Salmonson Jay D. , Callahan Debra A. , Town Richard P. J.
Published: May 2010

The National Ignition Campaign, tasked with designing and fielding targets for fusion ignition experiments on the National Ignition Facility (NIF) [G. H. Miller, E. I. Moses, and C. R. Wuest, Nucl. Fusion 44, S228 (2004)], has carried forward three complementary target designs for the past several years: a beryllium ablator design, a plastic ablator design, and a high-density carbon or synthetic diamond design. This paper describes current simulations and design optimization to develop the plastic ablator capsule design as a candidate for the first ignition attempt on NIF. The trade-offs in capsule scale and laser energy that must be made to achieve a comparable ignition probability to that with beryllium are emphasized. Large numbers of one-dimensional simulations, meant to assess the statistical behavior of the target design, as well as two-dimensional simulations to assess the target’s susceptibility to Rayleigh–Taylor growth are presented.
On the atmosphere of a moving body
Authors: Roenby Johan , Aref Hassan
Published: May 2010

We explore whether a rigid body moving freely with no circulation around it in a two-dimensional ideal fluid can carry a fluid “atmosphere” with it in its motion. Somewhat surprisingly, the answer appears to be “yes.” When the body is elongated and the motion is dominated by rotation, we demonstrate numerically that, indeed, regions of fluid follow the body in its motion. We see this as an example of the stability of Kolmogorov–Arnold–Moser tori. These observations of an atmosphere around a moving body with no circulation around it appear to be new.
Linear stability of a doubly periodic array of vortices to three-dimensional perturbations
Authors: Pathak A. K. , Bhattacharyya S. N.
Published: May 2010

The linear stability of a doubly periodic array of vortices to three-dimensional perturbations is studied. The instabilities are separated into symmetric and antisymmetric modes. For two-dimensional disturbances only the symmetric mode is found to be unstable. The antisymmetric mode shows a peak in growth rate at long wavelengths. This is attributed to the Crow instability. For short wavelengths both symmetric and antisymmetric modes are found to have similar growth rates. This is attributed to the elliptical instability and it is found to occur even when the vortex cells are square, a physical explanation for which is provided, but for elongated vortex cells the growth rates are higher. Viscosity is found to have a strong stabilizing influence on short wavelength perturbations.
Assessment of TD-DFT methods and of various spin scaled CIS(D) and CC2 versions for the treatment of low-lying valence excitations of large organic dyes
Authors: Goerigk Lars , Grimme Stefan
Published: May 2010

We present an extension of our previously published benchmark set for low-lying valence transitions of large organic dyes [L. Goerigk et al., Phys. Chem. Chem. Phys. 11, 4611 (2009)]. The new set comprises in total 12 molecules, including two charged species and one with a clear charge-transfer transition. Our previous study on TD-DFT methods is repeated for the new test set with a larger basis set. Additionally, we want to shed light on different spin-scaled variants of the configuration interaction singles with perturbative doubles correction [CIS(D)] and the approximate coupled cluster singles and doubles method (CC2). Particularly for CIS(D) we want to clarify, which of the proposed versions can be recommended. Our results indicate that an unpublished SCS-CIS(D) variant, which is implemented into the TURBOMOLE program package, shows worse results than the original CIS(D) method, while other modified versions perform better. An SCS-CIS(D) version with a parameterization, that has already been used in an application by us recently [L. Goerigk and S. Grimme, ChemPhysChem 9, 2467 (2008)], yields the best results. Another SCS-CIS(D) version and the SOS-CIS(D) method [Y. M. Rhee and M. Head-Gordon, J. Phys. Chem. A 111, 5314 (2007)] perform very similar, though. For the electronic transitions considered herein, there is no improvement observed when going from the original CC2 to the SCS-CC2 method but further adjustment of the latter seems to be beneficial. Double-hybrid density functionals belong to best methods tested here. Particularly B2GP-PLYP provides uniformly good results for the complete set and is considered to be close to chemical accuracy within an ab initio theory of color. For conventional hybrid functionals, a Fock-exchange mixing parameter of about 0.4 seems to be optimum in TD-DFT treatments of large chromophores. A range-separated functional such as, e.g., CAM-B3LYP seems also to be promising.
High-temperature electrical transport behaviors of the layered Ca2Co2O5-based ceramics
Authors: Lan Jinle , Lin Yuan-Hua , Li Guo-jing , Xu Shaoliang , Liu Yong , Nan Ce-Wen , Zhao Shu-Jin
Published: May 2010

Textured Bi-substituted Ca2Co2O5 ceramics have been prepared using a coprecipitation method combined with spark plasma sintering. The Bi substitution is effective in increasing the grain orientation of the Ca2Co2O5-based ceramics (from 0.46 to 0.85). Electrical conductivity increases obviously with partial substitution of Bi3+ for Ca2+ (from 113.9 to 142.4 S/cm at 973 K). The Ca1.92Bi0.08Co2O5 sample exhibits higher power factor (4.4×10−4 W m−1 K−2) than that of pure Ca2Co2O5 (3.2×10−4 W m−1 K−2) at 973 K, indicating that the Ca2Co2O5 system is another promising p-type material for high-temperature thermoelectric applications.
Tungsten oxide as a buffer layer inserted at the SnO2/p-a-SiC interface of pin-type amorphous silicon based solar cells
Authors: Fang Liang , Baik Seung Jae , Lim Koeng Su , Yoo Seung Hyup , Seo Myung Soo , Kang Sang Jung , Won Seo Jung
Published: May 2010

A thermally evaporated p-type amorphous tungsten oxide (p-a-WO3) film was introduced as a buffer layer between SnO2 and p-type amorphous silicon carbide (p-a-SiC) of pin-type amorphous silicon based solar cells. Using the Schottky barrier model, it is shown that the p-a-WO3 layer lowered the Schottky barrier height, which enhanced the open circuit voltage and the blue response compared to a bufferless cell. By inserting a 2-nm-thick p-a-WO3 layer between SnO2 and an 8-nm-thick p-a-SiC layer, the conversion efficiency was increased by 7.3% compared to the optimized bufferless cell only with a 10-nm-thick p-a-SiC window layer.
Selective atomic layer deposition of HfO2 on copper patterned silicon substrates
Authors: Tao Qian , Jursich Gregory , Takoudis Christos
Published: May 2010

Selective atomic layer deposition (ALD) was performed on copper patterned silicon substrates to selectively deposit HfO2 film on silicon. The selectivity is based on differences of surface physics/chemistry rather than use of any molecular masking such as self-assembled monolayers. On silicon, the growth rate of HfO2 is 0.11 nm /cycle with no initial inhibition of film growth, while on copper no HfO2 deposition was observed up to at least 25 ALD cycles. The selective growth on silicon over copper at 25 ALD cycles provides a patterned film deposition at thicknesses of 2.8 nm HfO2 which is relevant to semiconductor nanofabrication.
Biexciton emission from sol-gel ZnMgO nanopowders
Authors: Chia C. H. , Lai Y. J. , Hsu W. L. , Han T. C. , Chiou J. W. , Hu Y. M. , Lin Y. C. , Fan W. C. , Chou W. C.
Published: May 2010

We studied the power-dependent photoluminescence of Zn1−xMgxO nanopowders grown by sol-gel method, at temperature T=100 K. At moderate optical pumping intensity, a nonlinear emission band due to the radiative recombination of free biexcitons was detected. We found that the free biexciton binding energies of Zn1−xMgxO nanopowder (0.01≤x≤0.05) are nearly constant (13.5±1.5 meV).
Pressure-independent point in current-voltage characteristics of coplanar electrode microplasma devices operated in neon
Authors: Meng Lingguo , Xing Jianping , Liang Zhihu , Liu Chunliang , Lin Zhaojun
Published: May 2010

We introduce the idea of a pressure-independent point (PIP) in a group of current-voltage curves for the coplanar electrode microplasma device (CEMPD) at neon pressures ranging from 15 to 95 kPa. We studied four samples of CEMPDs with different sizes of the microcavity and observed the PIP phenomenon for each sample. The PIP voltage depends on the area of the microcavity and is independent of the height of the microcavity. The PIP discharge current, IPIP, is proportional to the volume (Vol) of the microcavity and can be expressed by the formula IPIP=IPIP0+D×Vol. For our samples, IPIP0 (the discharge current when Vol is zero) is about zero and D (discharge current density) is about 3.95 mA mm−3. The error in D is 0.411 mA mm−3 (less than 11% of D). When the CEMPD operates at VPIP, the discharge current is quite stable under different neon pressures.
The effect of nanocrystallite size in monoclinic HfO2 films on lattice expansion and near-edge optical absorption
Authors: Cisneros-Morales M. C. , Aita C. R.
Published: May 2010

Nanocrystalline monoclinic HfO2 films were sputter deposited on fused silica substrates, air annealed at 573 to 1273 K to affect crystallite growth, and analyzed by x-ray diffraction and spectrophotometry. Lattice expansion occurs with diminishing crystallite size. O 2p→Hf 5d interband absorption dominates the optical edge at energy E≥6.24 eV, with an optical band gap, Eo=5.48±0.023, which is independent of crystallite size. However, the strength of a localized resonant band, with onset at 5.65 eV and maximum at 5.94 eV, is affected by crystallite size. Its polaronic origin in a perfect HfO2 lattice is discussed.
DJ-1 is critical for mitochondrial function and rescues PINK1 loss of function
Authors: Hao Ling-Yang , Giasson Benoit I. , Bonini Nancy M.
Published: May 2010

Mutations or deletions inPARKIN/PARK2,PINK1/PARK6, andDJ-1/PARK7lead to autosomal recessive parkinsonism. InDrosophila, deletions inparkinandpink1result in swollen and dysfunctional mitochondria in energy-demanding tissues. The relationship betweenDJ-1and mitochondria, however, remains unclear. We now report thatDrosophilaand mouse mutants inDJ-1show compromised mitochondrial function with age. Flies deleted forDJ-1manifest similar defects aspink1andparkinmutants: male sterility, shortened lifespan, and reduced climbing ability. We further found poorly coupled mitochondria in vitro and reduced ATP levels in fly and mouseDJ-1mutants. Surprisingly, up-regulation ofDJ-1can amelioratepink1, but notparkin,mutants inDrosophila; cysteine C104 (analogous to C106 in human) is critical for this rescue, implicating the oxidative functions of DJ-1 in this property. These results suggest thatDJ-1is important for proper mitochondrial function and acts downstream of, or in parallel to,pink1. These findings linkDJ-1,pink1, andparkinto mitochondrial integrity and provide the foundation for therapeutics that link bioenergetics and parkinsonism.
Innate and adaptive immune correlates of vaccine and adjuvant-induced control of mucosal transmission of SIV in macaques
Authors: Sui Yongjun , Zhu Qing , Gagnon Susan , Dzutsev Amiran , Terabe Masaki , Vaccari Monica , Venzon David , Klinman Dennis , Strober Warren , Kelsall Brian , Franchini Genoveffa , Belyakov Igor M. , Berzofsky Jay A.
Published: May 2010

Adjuvant effects on innate as well as adaptive immunity may be critical for inducing protection against mucosal HIV and simian immunodeficiency virus (SIV) exposure. We therefore studied effects of Toll-like receptor agonists and IL-15 as mucosal adjuvants on both innate and adaptive immunity in a peptide/poxvirus HIV/SIV mucosal vaccine in macaques, and made three critical observations regarding both innate and adaptive correlates of protection: (
i
) adjuvant-alone without vaccine antigen impacted the intrarectal SIVmac251 challenge outcome, correlating with surprisingly long-lived APOBEC3G (A3G)-mediated innate immunity; in addition, even among animals receiving vaccine with adjuvants, viral load correlated inversely with A3G levels; (
ii
) a surprising threshold-like effect existed for vaccine-induced adaptive immunity control of viral load, and only antigen-specific polyfunctional CD8
+
T cells correlated with protection, not tetramer
+
T cells, demonstrating the importance of T-cell quality; (
iii
) synergy was observed between Toll-like receptor agonists and IL-15 for driving adaptive responses through the up-regulation of IL-15Rα, which can present IL-15
in trans
, as well as for driving the innate A3G response. Thus, strategic use of molecular adjuvants can provide better mucosal protection through induction of both innate and adaptive immunity.
Quantum Monte Carlo computations of phase stability, equations of state, and elasticity of high-pressure silica
Authors: Driver K. P. , Cohen R. E. , Wu Zhigang , Militzer B. , Ríos P. López , Towler M. D. , Needs R. J. , Wilkins J. W.
Published: May 2010

Silica (SiO2) is an abundant component of the Earth whose crystalline polymorphs play key roles in its structure and dynamics. First principle density functional theory (DFT) methods have often been used to accurately predict properties of silicates, but fundamental failures occur. Such failures occur even in silica, the simplest silicate, and understanding pure silica is a prerequisite to understanding the rocky part of the Earth. Here, we study silica with quantum Monte Carlo (QMC), which until now was not computationally possible for such complex materials, and find that QMC overcomes the failures of DFT. QMC is a benchmark method that does not rely on density functionals but rather explicitly treats the electrons and their interactions via a stochastic solution of Schrödinger’s equation. Using ground-state QMC plus phonons within the quasiharmonic approximation of density functional perturbation theory, we obtain the thermal pressure and equations of state of silica phases up to Earth’s core–mantle boundary. Our results provide the best constrained equations of state and phase boundaries available for silica. QMC indicates a transition to the denseα-PbO2structure above the core-insulating D” layer, but the absence of a seismic signature suggests the transition does not contribute significantly to global seismic discontinuities in the lower mantle. However, the transition could still provide seismic signals from deeply subducted oceanic crust. We also find an accurate shear elastic constant for stishovite and its geophysically important softening with pressure.
Enzootic and epizootic dynamics of the chytrid fungal pathogen of amphibians
Authors: Briggs Cheryl J. , Knapp Roland A. , Vredenburg Vance T.
Published: May 2010

Chytridiomycosis, the disease caused by the chytrid fungus,
Batrachochytrium dendrobatidis
(Bd), has contributed to amphibian population declines and extinctions worldwide. The impact of this pathogen, however, varies markedly among amphibian species and populations. Following invasion into some areas of California's Sierra Nevada, Bd leads to rapid declines and local extinctions of frog populations (
Rana muscosa
,
R. sierrae
). In other areas, infected populations of the same frog species have declined but persisted at low host densities for many years. We present results of a 5-year study showing that infected adult frogs in persistent populations have low fungal loads, are surviving between years, and frequently lose and regain the infection. Here we put forward the hypothesis that fungal load dynamics can explain the different population-level outcomes of Bd observed in different areas of the Sierra Nevada and possibly throughout the world. We develop a model that incorporates the biological details of the Bd-host interaction. Importantly, model results suggest that host persistence versus extinction does not require differences in host susceptibility, pathogen virulence, or environmental conditions, and may be just epidemic and endemic population dynamics of the same host–pathogen system. The different disease outcomes seen in natural populations may result solely from density-dependent host–pathogen dynamics. The model also shows that persistence of Bd is enhanced by the long-lived tadpole stage that characterize these two frog species, and by nonhost Bd reservoirs.