cssi/SciSciGPT-SciSciNet huggingface dataset:
Evaluation of defect-related diffusion in semiconductors by electrooptical sampling

The electrooptical sampling technique is used to assess the electrical behavior of Ohmic contact regions in GaAs. For this purpose unique Ohmic contact coplanar waveguides were fabricated and tested. A reduced electrooptical sampling signal is detected in certain Ohmic contact regions. Since the electrical fields present in this device are known a priori, the deviation of the electrooptical signal from its nominal value is attributed to a deviation in the electrooptical coefficient. Defects introduced during the annealing step of the Ohmic contact accelerated by existing dislocations are discussed as a mechanism capable of disrupting the electrooptic coefficient. A simple phenomenological diffusion model is presented to explain the mechanism responsible for the nulling of the electrooptical coefficient.
Analyzing chiral symmetry breaking in supersymmetric gauge theories

Abstract We compare gap equation predictions for the spontaneous breaking of global symmetries in supersymmetric Yang–Mills theory to nonperturbative results from holomorphic effective action techniques. In the theory without matter fields, both approaches describe the formation of a gluino condensate. With N f flavors of quark and squark fields, and with N f below a certain critical value, the coupled gap equations have a solution for quark and gluino condensate formation, corresponding to breaking of global symmetries and of supersymmetry. This appears to disagree with the newer nonperturbative techniques, but the reliability of gap equations in this context and whether the solution represents the ground state remain unclear.
On QCD String Theory and AdS Dynamics

The AdS/CFT correspondence of elementary string theory has been recently suggested as a “microscopic” approach to QCD string theory in various dimensions. We use the microscopic theory to show that the ultraviolet regime on the string world-sheet is mapped to the ultraviolet effects in QCD. In the case of QCD_2, a world-sheet path integral representation of QCD strings is known, in terms of a topological rigid string theory whose world-sheet supersymmetry is reminiscent of Parisi-Sourlas supersymmetry. We conjecture that the supersymmetric rigid string theory is dual to the elementary Type IIB string theory in the singular AdS background that corresponds to the large-N limit of QCD_2. We also generalize the rigid string with world-sheet Parisi-Sourlas supersymmetry to dimensions greater than two, and argue that the theory is asymptotically free, a non-zero string tension is generated dynamically through dimensional transmutation, and the theory is topological only asymptotically in the ultraviolet.
Vibrational feedback control of time delay systems

This paper applies vibrational feedback control to time lag systems. Averaging theory for differential delay systems is presented and then applied to aid in the design of periodic controllers. Both stabilization and transient issues are discussed. An illustrative example is given which demonstrates that the proposed controller: 1) provides superior robustness properties in comparison to time-invariant controllers when applied correctly; 2) is not robust with respect to unmodeled delays; and 3) does not have zero placement capabilities, in the sense defined in the paper.
Cinematography of spatial and temporal variations in auroral forms with an image orthicon tv system.

A new technique for cinematographic recording at 24 frames per see of variations in auroral forms is discussed. The equipment is a very sensitive image orthicon television system from whose monitor the image is photographed with a 16-mm movie camera. The technique permits changes in auroral forms to be studied which occur in as little as 1/24 sec.
Excess Dietary Protein Can Adversely Affect Bone

The average American diet, which is high in protein and low in fruits and vegetables, generates a large amount of acid, mainly as sulfates and phosphates. The kidneys respond to this dietary acid challenge with net acid excretion, as well as ammonium and titratable acid excretion. Concurrently, the skeleton supplies buffer by active resorption of bone. Indeed, calciuria is directly related to net acid excretion. Different food proteins differ greatly in their potential acid load, and therefore in their acidogenic effect. A diet high in acid-ash proteins causes excessive calcium loss because of its acidogenic content. The addition of exogenous buffers, as chemical salts or as fruits and vegetables, to a high protein diet results in a less acid urine, a reduction in net acid excretion, reduced ammonium and titratable acid excretion, and decreased calciuria. Bone resorption may be halted, and bone accretion may actually occur. Alkali buffers, whether chemical salts or dietary fruits and vegetables high in potassium, reverse acid-induced obligatory urinary calcium loss. We conclude that excessive dietary protein from foods with high potential renal acid load adversely affects bone, unless buffered by the consumption of alkali-rich foods or supplements.
A novel technology for fabricating gratings of any chirp characteristics by design

We demonstrated a novel material and device technology to form gratings of any chirp characteristics by design. Furthermore, the chirp characteristics can be tuned dynamically after the device is fabricated. The device was fabricated on low cost polymer material polydimethylsiloxane (PDMS). This inorganic polymer possesses highly desirable optical and mechanical properties and is chemically stable and easy to process. Using PDMS molding techniques, we are able to control the device geometry and subsequently the chirp profile precisely. This technology shows promise in dense wavelength-division multiplexing, and nontelecommunication applications including chemical and molecular sensing and biomedical microfluidic devices.
Industry Growth and Capital Allocation: Does Having a Market- or Bank-Based System Matter?

Are market-based or bank-based financial systems better at financing the expansion of industries that depend heavily on external finance, facilitating the formation of new establishments, and improving the efficiency of capital allocation across industries? We find evidence for neither the market-based nor the bank-based hypothesis. While legal system efficiency and overall financial development boost industry growth, new establishment formation, and efficient capital allocation, having a bank-based or market-based system per se does not seem to matter much.
α-Sheet: The Toxic Conformer in Amyloid Diseases?

A novel secondary structure, the α-sheet, was identified through molecular dynamics (MD) simulations of various proteins associated with amyloid diseases under amyloidogenic conditions. The structure was first predicted by Pauling and Corey, and it has been directly observed in crystal structures of “nonnatural peptides”. There are occurrences of α-strands and α-sheets in the Protein Data Bank, but they are rare. We propose that α-sheet is formed during the conformational changes associated with amyloidosis and that it may represent the toxic conformer. Here, structural properties of the α-sheet, background information, and experimental support for this novel structure are presented. Finally we speculate about the possible role of this conformation in disease.
Surgical Alternatives for Treating Peyronie’s Disease

Editorial Comment: Most men requiring surgical reconstruction for Peyronie’s disease have curvature less than 60 degrees without significant hourglass deformity. Use of either a simple “16-dot” plication procedure or insertion of an inflatable penile prosthesis (with modeling if necessary) usually achieves excellent results. Graft procedure are technically much more demanding and carry additional risks, and, thus, should generally be performed in a subspecialty setting.
Antigen-specific B-cell receptor sensitizes B cells to infection by influenza virus

Transnuclear mice are generated from B cells with a receptor specific for the haemagglutinin of influenza A virus; the authors show that influenza virus can infect and deplete haemagglutinin-specific B cells in the lung, which might confer a replicative advantage to the virus and allow it to evade an early neutralizing response. Using FluBI mice, a transgenic system containing B cells with a cellular receptor specific for the HA antigen of influenza, Hidde Ploegh and colleagues show that influenza virus can infect and deplete HA-specific B cells in the lung. The authors speculate that by targeting and killing influenza-specific B cells, the virus may gain a replicative advantage sufficient for it to evade an early neutralizing response and to become established in the lung. Influenza A virus-specific B lymphocytes and the antibodies they produce protect against infection1. However, the outcome of interactions between an influenza haemagglutinin-specific B cell via its receptor (BCR) and virus is unclear. Through somatic cell nuclear transfer we generated mice that harbour B cells with a BCR specific for the haemagglutinin of influenza A/WSN/33 virus (FluBI mice). Their B cells secrete an immunoglobulin gamma 2b that neutralizes infectious virus. Whereas B cells from FluBI and control mice bind equivalent amounts of virus through interaction of haemagglutinin with surface-disposed sialic acids, the A/WSN/33 virus infects only the haemagglutinin-specific B cells. Mere binding of virus is not sufficient for infection of B cells: this requires interactions of the BCR with haemagglutinin, causing both disruption of antibody secretion and FluBI B-cell death within 18 h. In mice infected with A/WSN/33, lung-resident FluBI B cells are infected by the virus, thus delaying the onset of protective antibody release into the lungs, whereas FluBI cells in the draining lymph node are not infected and proliferate. We propose that influenza targets and kills influenza-specific B cells in the lung, thus allowing the virus to gain purchase before the initiation of an effective adaptive response.
Nitridomanganese(V) Complexes: Design, Preparation, and Use as Nitrogen Atom-Transfer Reagents

Oxidation of organic substrates by direct oxygen-atom transfer from transition-metal complexes is of fundamental importance and has been subject to intensive investigation. Highly selective methods for alkene epoxidation and dihydroxylation have been described and are commonly employed in synthesis. By contrast, significantly fewer reagents and protocols are available for the analogous nitrogen-atom-transfer process, despite the enormous potential utility of such methodology. Recent efforts by other groups to develop general olefin amination strategies have led to impressive advances in both metalcatalyzed hydroxyamination and aziridination. Our interest in this area has resulted in the preparation and characterization of novel nitridomanganese complexes which may be activated for nitrogen-atom transfer. Pivotal to the success of this research has been the development of new protocols for the construction of these manganese nitride (Mn≡N) reagents. These systems have proven to be versatile and effective aminating agents with different classes of olefins which include both silyl enol ethers and glycals (eq 1). The following account documents these findings and highlights the unique chemistry of these complexes as nitrogen-atom-transfer reagents.
Technology and Income Distribution Issues in Trade Models

In a world characterized by global competitive market conditions, technological improvements initially localized in one sector of one country cause real income changes at home and abroad, sometimes in paradoxical fashion. A foreign technological advance in the production of a commodity not produced at home may worsen the home country's real income. As well, a foreign technological advance in a commodity the home country exports may serve to raise home real incomes. These paradoxes are explained and related to the basic proposition that a country moving from autarky to free trade must gain. (JEL codes: F10, F11, O30) Copyright , Oxford University Press.
Theodore E. Woodward: 1914–2005

Dr. Woodward was born in Westminster, Maryland, on 22 March 1914. As a youngster, he accompanied his physician father on house calls, igniting a spark that would become a lifelong passion for medicine. He attended Westminster High School and then Franklin and Marshall College, where he lettered in 5 sports while earning a bachelor of science degree. He then entered the University of Maryland School of Medicine, graduating in 1938 with a medical degree and the hand in marriage of his classmate, Celeste C. Lauve. While in medical school, Dr. Woodward spent 2 summers as a subintern at the Tuberculosis Sanatorium in
Formation of Jets and Equatorial Superrotation on Jupiter

ThezonalflowinJupiter’suppertroposphereisorganizedintoalternatingretrogradeandprogradejets,with a prograde (superrotating) jet at the equator. Existing models posit as the driver of the flow either differential radiativeheatingoftheatmosphereorintrinsicheatfluxesemanatingfromthedeepinterior;however,theydo not reproduce all large-scale features of Jupiter’s jets and thermal structure. Here it is shown that the difficulties in accounting for Jupiter’s jets and thermal structure resolve if the effects of differential radiative heating and intrinsic heat fluxes are considered together, and if upper-tropospheric dynamics are linked to a magnetohydrodynamic(MHD)dragthatactsdeepintheatmosphereandaffectsthezonalflowawayfrombut not near the equator. Baroclinic eddies generated by differential radiative heating can account for the offequatorial jets; meridionally propagating equatorial Rossby waves generated by intrinsic convective heat fluxescanaccountfortheequatorialsuperrotation.Thezonalflowextendsdeeplyintotheatmosphere,withits speed changing with depth, away from the equator up to depths at which the MHD drag acts. The theory is supported by simulations with an energetically consistent general circulation model of Jupiter’s outer atmosphere. A simulation that incorporates differential radiative heating and intrinsic heat fluxes reproduces Jupiter’s observed jets and thermal structure and makes testable predictions about as yet unobserved aspects thereof. A control simulation that incorporates only differential radiative heating but not intrinsic heat fluxes producesoff-equatorialjetsbutnoequatorialsuperrotation;anothercontrolsimulationthatincorporatesonly intrinsic heat fluxes but not differential radiative heating produces equatorial superrotation but no offequatorial jets. The proposed mechanisms for the formation of jets and equatorial superrotation likely act in the atmospheres of all giant planets.
Effective capacity channel model for frequency-selective fading channels

To efficiently support quality of service (QoS) in future wireless networks, it is important to model a wireless channel in terms of connection-level QoS metrics such as data rate, delay and delay-violation probability. To achieve this, in [7], we proposed and developed a link-layer channel model termed effective capacity (EC) for flat fading channels. In this paper, we apply the effective capacity technique to modeling frequency selective fading channels. Specifically, we utilize the duality between the distribution of a queue with superposition of N i.i.d. sources, and the distribution of a queue with a frequency-selective fading channel that consists of N i.i.d. sub-channels, to model a frequency selective fading channel. In the proposed model, a frequency selective fading channel is modeled by three EC functions; we also propose a simple and efficient algorithm to estimate these EC functions. Simulation results show that the actual QoS metric is closely approximated by the QoS metric predicted by the proposed EC channel model. The accuracy of the prediction using our model can translate into efficiency in admission control and resource reservation.
The Boltzmann equation for gluons at early times after a heavy ion collision

Abstract A Boltzmann equation is given for the early stages of evolution of the gluon system produced in a head-on heavy ion collision. The collision term is taken from gluon-gluon scattering in the one-gluon approximation. 〈p⊥〉 and 〈pz2〉 are evaluated as a function of time using initial conditions taken from the McLerran–Venugopalan model.
An Economic Analysis of Fresh Fruit and Vegetable Consumption: Implications for Overweight and Obesity among Higher- and Lower-Income Consumers

This paper examines the consumption patterns of higher- and lower-income consumers for fresh fruit and vegetables. Supermarket scanner data are obtained for every fresh fruit and vegetable sold in six supermarkets over 69 weeks during 2001 and 2002. These data are collected from three inner-city stores (lower income) and three suburban stores (higher income) in Columbus, Ohio. These data are segmented into eight sub-categories of fruit and six sub-categories of vegetables. An error correction model consisting of 14 equations is specifi ed and estimated using the time series cross-section regression procedure in SAS. Results show lower-income consumers to be more price-sensitive and more careful shoppers, as compared to higher-income shoppers. Lower-income shoppers are shown to make larger purchases from the lower-priced sub-categories of fruit and vegetables and they invariably pay lower prices. These purchase patterns suggest that income constrains the purchase behavior of lower-income consumers and, if higher consumption of fresh fruits and vegetables is critical to alleviating overweight and obesity among lower-income Americans, the analyses suggest a need for some type of market intervention to make fresh fruits and vegetables more affordable (e.g., price subsidies).
Signaling Network State Predicts Twist-Mediated Effects on Breast Cell Migration Across Diverse Growth Factor Contexts

Epithelial-mesenchymal transition (EMT), whether in developmental morphogenesis or malignant transformation, prominently involves modified cell motility behavior. Although major advances have transpired in understanding the molecular pathways regulating the process of EMT induction per se by certain environmental stimuli, an important outstanding question is how the activities of signaling pathways governing motility yield the diverse movement behaviors characteristic of pre-induction versus postinduction states across a broad landscape of growth factor contexts. For the particular case of EMT induction in human mammary cells by ectopic expression of the transcription factor Twist, we found the migration responses to a panel of growth factors (EGF, HRG, IGF, HGF) dramatically disparate between confluent pre-Twist epithelial cells and sparsely distributed post-Twist mesenchymal cells—but that a computational model quantitatively integrating multiple key signaling node activities could nonetheless account for this full range of behavior. Moreover, motility in both conditions was successfully predicted a priori for an additional growth factor (PDGF) treatment. Although this signaling network state model could comprehend motility behavior globally, modulation of the network interactions underlying the altered pathway activities was identified by ascertaining differences in quantitative topological influences among the nodes between the two conditions.
Nonlinear effects of beam-plasma instabilities on neutralized propagation of intense ion beams in background plasma

The streaming of an intense ion beam relative to the background plasma can cause the development of fast electrostatic collective instabilities. In this paper we examine numerically the defocusing effects of two-stream instability on the ion beam propagating in neutralizing background plasma. The scaling laws for the average de-focusing forces on the beam ions are identified, and confirmed by comparison with numerical simulations. These scalings can be used in the development of realistic ion beam compression scenarios in present and next-generation ion-beam-driven experiments.
Time and Work in Eighteenth-Century London

Witnesses' accounts are used to analyze changes in working hours between 1750 and 1800. Two findings stand out. The article demonstrates that the information contained in witnesses' accounts allows us to reconstruct historical time-budgets and provides extensive tests of the new method. Estimates of annual labor input in 1749/63 and 1799/1803 are presented. It emerges that the number of annual working hours changed rapidly between the middle and the of the eighteenth century. These findings have important implications for the issue of total factor productivity during the Industrial Revolution.
Do Politicians Use Policy to Make Politics? The Case of Public Sector Labor Laws

Schattschneider's insight that "policies make politics" has played an influential role in the modern study of political institutions and public policy. Yet if policies do indeed make politics, rational politicians clearly have opportunities to use policies to create a future structure of politics more to their own advantage—and this strategic dimension has gone almost entirely unexplored. Do politicians actually use policies to make politics? Under what conditions? In this paper, we develop a theoretical argument about what can be expected from strategic politicians, and we carry out an empirical analysis on a policy development that is particularly instructive: the adoption of public sector collective bargaining laws by the states during the 1960s, 1970s, and early 1980s—laws that fueled the rise of public sector unions, and "made politics" to the great advantage of Democrats over Republicans.
Signatures of a Maxwellian component in shock-accelerated electrons in GRBs

Recent particle-in-cell simulations suggest that a large f raction of the energy dissipated in a relativistic shock is deposited into a Maxwellian distribu tion of electrons that is connected to the high-energy power-law tail. Here, we explore the observational implications of such a mixed thermal-nonthermal particle distribution for the a fterglow and prompt emission of gamma-ray bursts. When the Maxwellian component dominates the energy budget, the afterglow lightcurves show a very steep decline phase followed by a more shallow decay when the characteristic synchrotron frequency crosses the observe d band. The steep decay appears in the X-rays at∼100 sec after the burst and is accompanied by a characteristi c hard-soft-hard spectral evolution that has been observed in a large number of early afterglows. If internal shocks produce a similar mixed electron distribution, a bump is expected at the synchrotron peak of theν fν spectrum.
Synthesis of fluorinated derivatives of methionine and 5′-deoxy-5′-(methylthio)-adenosine using the mccarthy transformation of sulfoxides to α-fluoro thioethers

Abstract Treatment of N-acetylmethionine sulfoxide methyl ester with diethylamino- sulfur trifluoride (DAST) or dimethylaminosulfur trifluoride (meDAST) yielded N-acetyl-S-(monofluoromethyl)homocysteine methyl ester as the sole fluorinated product. In contrast, treatment of 2′,3′-di-O-acetyl-5′-(methylthio)adenosine sulfoxide with DAST or meDAST unexpectedly produced three novel fluorinated products.
Software components in a data structure precompiler

This research aims to simplify component creation and reduce the necessity of implementing new components. It concentrates more on programmer productivity and code efficiency than on program evolution and maintenance. The project is called PREDATOR. PREDATOR is a data structure precompiler that generates efficient code for maintaining and querying complex data structures. It embodies a novel component reuse technology that transcends traditional generic data types. The authors explain the concepts of this work and the prototype system. It is shown that complex data structures can be specified as compositions of software building blocks. Performance results are presented that compare PREDATOR output to hand-optimized programs. >
Directed-graph epidemiological models of computer viruses

The strong analogy between biological viruses and their computational counterparts has motivated the authors to adapt the techniques of mathematical epidemiology to the study of computer virus propagation. In order to allow for the most general patterns of program sharing, a standard epidemiological model is extended by placing it on a directed graph and a combination of analysis and simulation is used to study its behavior. The conditions under which epidemics are likely to occur are determined, and, in cases where they do, the dynamics of the expected number of infected individuals are examined as a function of time. It is concluded that an imperfect defense against computer viruses can still be highly effective in preventing their widespread proliferation, provided that the infection rate does not exceed a well-defined critical epidemic threshold. >
Alpha channeling with high-field launch of lower hybrid waves

Although lower hybrid waves are effective at driving currents in present-day tokamaks, they are expected to interact strongly with high-energy particles in extrapolating to reactors. In the presence of a radial alpha particle birth gradient, this interaction can take the form of wave amplification rather than damping. While it is known that this amplification more easily occurs when launching from the tokamak high-field side, the extent of this amplification has not been made quantitative. Here, by tracing rays launched from the high-field-side of a tokamak, the required radial gradients to achieve amplification are calculated for a temperature and density regime consistent with a hot-ion-mode fusion reactor. These simulations, while valid only in the linear regime of wave amplification, nonetheless illustrate the possibilities for wave amplification using high-field launch of the lower hybrid wave.
A dielectric model of the vegetation effects on the microwave emission from soils

A layer of vegetation over the soil surface absorbs some of the radiation emitted from the soil and emits at its own temperature. This results in a reduction of the information in the microwave radiation about the soil surface. To study this problem further the authors use the model of F.T. Ulaby and M.A. El-Rayes (1987) for the dielectric constant of vegetation to estimate the absorption loss and optical depth, tau , of plant canopies for frequencies between 1 and 40 GHz. The authors treated tau as the product of a vegetation parameter b and vegetation water content, VW. They compared both the linear and square root (refractive) mixing models with the observed data in terms of the b parameter. These data were obtained from published reports on the values of tau and VW for crops ranging from prairie grass to corn and soybeans. The data fit the curve for the refractive model quite well. For the refractive model the value of b was independent of VW, while for the linear model there was some dependence on VW. For both models b is roughly proportional to the frequency. >
Star Formation and Asymmetry in the Spiral Arms of M51: Variable Star Formation Caused by More than One Spiral Density Wave

In the inner 3 kpc of M51, we find that logarithmic spirals provide good fits to the peak intensities in molecular gas observed by the Berkeley-Illinois-Maryland Association array in the CO (J = 1–0) emission line along the spiral arms. However, we measure significant asymmetries between the location and density of the arms observed on one side of the galaxy compared with those on the opposite side. Between a radius of 1 and 2.2 kpc, the gas distribution traced in CO is lopsided with densities twice as large in one arm than the opposite one. In the same region, the spiral arms are offset by 20° from the position of the arm on the opposite side of the galaxy after a rotation of 180°. We use the ratio of CO emission to the emission in the Paα hydrogen recombination line to estimate the efficiency of star formation along each arm. Except for a narrow region at about 2 kpc in which star formation is surprisingly inefficient, the gas depletion time is approximately 200 million years despite large variations in the molecular gas density in the arms. We account for the deviations from two-armed bisymmetric structure with a simple model that includes an additional three-armed spiral density wave. This model accounts for the angular offset between the arm on one side compared with its opposite, the lopsided distribution in molecular gas, and interarm star formation to the northeast of the galaxy nucleus. Since the star formation efficiency is unaffected by the variations in gas density, and the variations in gas density can be accounted for by the presence of an additional three-armed density wave, we suggest that the star formation rate is variable and is highest where and when the maxima of the two spiral density waves coincide or constructively add. The inner region of M51 provides good evidence for the presence of more than one spiral density wave and a resulting variable rate of star formation.
Governing for the Common Good

The proper object of global health governance (GHG) should be the common good, ensuring that all people have the opportunity to flourish. A well-organized global society that promotes the common good is to everyone's advantage. Enabling people to flourish includes enabling their ability to be healthy. Thus, we must assess health governance by its effectiveness in enhancing health capabilities. Current GHG fails to support human flourishing, diminishes health capabilities and thus does not serve the common good. The provincial globalism theory of health governance proposes a Global Health Constitution and an accompanying Global Institute of Health and Medicine that together propose to transform health governance. Multiple lines of empirical research suggest that these institutions would be effective, offering the most promising path to a healthier, more just world.
Hadamard spaces with isolated flats

We explore the geometry of nonpositively curved spaces with isolated flats, and its consequences for groups that act properly discontinuously, cocompactly, and isometrically on such spaces. We prove that the geometric boundary of the space is an invariant of the group up to equivariant homeomorphism. We also prove that any such group is relatively hyperbolic, biautomatic, and satisfies the Tits Alternative. The main step in establishing these results is a characterization of spaces with isolated flats as relatively hyperbolic with respect to flats. Finally we show that a CAT(0) space has isolated flats if and only if its Tits boundary is a disjoint union of isolated points and standard Euclidean spheres. In an appendix written jointly with Hindawi, we extend many of the results of this article to a more general setting in which the isolated subspaces are not required to be flats. AMS Classification numbers Primary: 20F67 Secondary: 20F69
The payout phase of pension systems : a comparison of five countries

This paper provides a comparative summary of the payout phase of pension systems in five countries -- Australia, Chile, Denmark, Sweden, and Switzerland. All five countries have large pension systems with mandatory or quasi-mandatory retirement savings schemes. But they exhibit important differences in the structure and role of different pillars, regulation of payout options, level of annuitization, market structure, capital regulations, risk management, and use of risk sharing arrangements. The paper summarizes the experience of these countries and highlights the lessons they offer to other countries.
Transverse Force on Quarks in DIS

The $x^2$-moment of the twist-3 polarized parton distribution $g_2(x)$ is related to the transverse force acting on the active quark in deep-inelastic scattering off a transversely polarized nucleon immediately after it has absorbed the virtual photon. Lattice calculations of the corresponding matrix element as well as experimental measurements of $g_2(x)$ are used to estimate sign and magnitude of this force. Similarly, the $x^2$-moment of the chirally odd twist-3 unpolarized parton distribution $e(x)$ can be related to the transverse force experienced by a transversely polarized quark ejected from a transversely polarized nucleon.
Accuracy of equation-of-state formulations

The accuracy of equation-of-state formulations is compared for theoretical total energies or experimental pressure-volume measurements for H{sub 2}, Ne, Pt, and Ta. This spans the entire range of compression found for minerals and volatiles in the Earth. The Vinet equation is found to be most accurate. The origin of the behavior of different equation-of-state formulations is discussed. It is shown that subtle phase transitions can be detected by examining the residuals from an equation-of-state fit. A change in the electronic structure of Ta is found at high pressures using this procedure, and a possible new transition in H{sub 2}.
Alpha Alumina Formation in Alum‐Derived Gamma Alumina

The formation of alpha alumina in gamma alumina obtained from ammonium alum was studied at 1150°C. The transformation occurs by a nucleation and growth process, preceded by an incubation time. Mechanical treatments of the gamma alumina markedly increase the density of nuclei and hence the transformation rate. The alpha alumina forms in porous colonies consisting of a single crystal with an interconnected wormy morphology.
The Economics of Managing Wildlife Disease

The spread of infectious disease among and between wild domesticated animals has become a major problem worldwide. Upon analyzing the dynamics of wildlife growth and infection when the disease animals cannot be identified separately from healthy wildlife prior to the kill, we find that harvest-based strategies alone have no impact on disease transmission. Other controls that directly influence disease transmission and/or mortality are required. Next, we analyze the socially optimal management of infectious wildlife. The model is applied to the problem of bovine tuberculosis among Michigan white-tailed deer, with non-selective harvests and supplemental feeding being the control variables. Using a two-state linear control model, we find a two-dimensional singular path is optimal (as opposed to a more conventional bang-bang solution) as part of a cycle that results in the disease remaining endemic in the wildlife. This result follows from non-selective harvesting and intermittent wildlife productivity gains from supplemental feeding.
Background and Scattered-Light Subtraction in the High-Resolution Echelle Modes of the Space Telescope Imaging Spectrograph

We present a simple, effective approach for estimating the on-order backgrounds of spectra taken with the highest resolution modes of the Space Telescope Imaging Spectrograph (STIS) on board the Hubble Space Telescope. Our scheme for determining the on-order background spectrum for STIS E140H and E230H observations uses moderate-order polynomial fits to the interorder scattered light visible in the two-dimensional STIS MAMA images. We present a suite of high-resolution STIS spectra to demonstrate that our background-subtraction routine produces the correct overall zero point as judged by the small residual flux levels in the centers of strongly saturated interstellar absorption lines. Although there are multiple sources of background light in STIS echelle mode data, this simple approach works very well for wavelengths longward of Lyα (λ 1215 A). At shorter wavelengths, the smaller order separation and generally lower signal-to-noise ratios of the data can reduce the effectiveness of our background estimation procedure. Slight artifacts in the background-subtracted spectrum can be seen in some cases, particularly at wavelengths of 1300 A. Most of these are caused by echelle scattering of strong spectral features into the interorder light. We discuss the limitations of high-resolution STIS data in light of the uncertainties associated with our background-subtraction procedure. We compare our background-subtracted STIS spectra with the Goddard High Resolution Spectrograph (GHRS) Ech-A observations of the DA white dwarf G191-B2B and the GHRS first-order G160M observations of the early-type star HD 218915. We find no significant differences between the GHRS data and the STIS data reduced with our method in either case.
The mid-latitude thermosphere☆

The F-region ionosphere at middle latitudes moves up and down in an irregular manner on a time scale of hours. This behavior is a manifestation of complex coupling between photochemical, fluid dynamical, and electrodynamical processes in the thermosphere. This closely coupled system is explored using a computationally simple theoretical model of the F-region. Observations of ionospheric properties, including the ion drift velocity vector and the neutral wind speed, have been made at the Arecibo Observatory in Puerto Rico. The theoretical model is used to interpret these observations in terms of electric currents and pressure gradients. Measured gradients in ionospheric properties imply local current divergence in the sense that the eastward gradient of the eastward current is significantly different from zero. It appears that current continuity is maintained by the exchange of charge between hemispheres, so that a gradient in the current in one hemisphere is matched by an opposite gradient at the conjugate point. The consequence of this global current pattern is that the conjugate ionospheres behave differently at night, with one F-region moving down when the other one moves up, and with one F-region tilting upward to the East when the other tilts downward to the East.
Free radical scavenging enzymes in fetal dysmorphogenesis among offspring of diabetic rats

Recent studies have suggested that the fetal dysmorphogenesis in diabetic pregnancies is associated with an increase in embryonic oxygen-free radicals. This excess of oxygen-free radicals may result from either overproduction or decreased clearance by the enzymatic scavenging mechanism. However, there are no in vivo data on the activity of embryonic oxygen-free radical scavenging enzymes. The purpose of the current study is to investigate whether this increase in embryonic oxygen-free radicals is the result of a change in the activity of the fetal oxygen-free radical scavenging/antioxidant enzymes during pregnancy complicated by maternal diabetes in an in vivo rat model. Thirty-six Sprague-Dawley rats were randomly assigned to one of two study groups: nondiabetic control and an untreated diabetic group. On day 12, fetuses were examined for crown-rump lengths, somite numbers, and external anomalies. The activity of fetal oxygen-free radical scavenging enzymes, including superoxide dismutase (SOD), glutathione peroxidase (GPX), and catalase (CAT), were determined. The untreated diabetic group of rats had a significantly higher mean blood glucose level than that of the nondiabetic controls and also a significantly lower weight gain, higher resorption rate, smaller embryonic size with lower total protein content, and a approximately 6-fold increase in the rate of fetal neural tube defects compared to the nondiabetic controls. Superoxide dismutase activity was significantly reduced in the embryos with neural tube defects regardless of maternal diabetic status (2.25 +/- 0.83 vs. 1.17 +/- 0.04 u/mg protein; P < 0.05). Glutathione peroxidase and catalase activity were significantly reduced in malformed versus normal-formed embryos of nondiabetic mothers (GPX-2.68 +/- 1.15 vs. 4.46 +/- 1.12 mu/mg protein, CAT -1.67 +/- 0.53 vs 2.49 +/- 0.61 u/mg protein respectively; P < 0.01). However, overall catalase activity was increased in embryos of diabetic mothers as compared to controls. Two-way analysis of variance identified fetal malformations as the variance associated with reduced fetal SOD activity, whereas maternal diabetes was associated with the increase in fetal catalase activity. Neither neural tube defect nor maternal diabetes was found to be the variable affecting fetal GPX activity, Fetal oxygen-free radical scavenging enzymes respond differently to the adverse environment created by maternal diabetes during pregnancy. Defects in embryonic SOD and catalase activity, regardless of maternal diabetic status, may reduce the ability of the fetus to clear free oxygen radicals, thereby exposing it to an increased oxidative load that may cause fetal dysmorphogenesis. The diabetic state of the mothers did not decrease embryonic activity of any of the scavenging enzymes. Therefore, although excess oxidative load, as observed in diabetes, may cause tissue injury and embryopathy, the mechanism does not appear to be a diabetes-induced reduction in the action of the scavenging enzymes.
An algorithm for constructing parsimonious hybridization networks with multiple phylogenetic trees

Phylogenetic network is a model for reticulate evolution. Hybridization network is one type of phylogenetic network for a set of discordant gene trees, and "displays" each gene tree. A central computational problem on hybridization networks is: given a set of gene trees, reconstruct the minimum (i.e. most parsimonious) hybridization network that displays each given gene tree. This problem is known to be NP-hard, and existing approaches for this problem are either heuristics or make simplifying assumptions (e.g. work with only two input trees or assume some topological properties). In this paper, we develop an exact algorithm (called PIRNC) for inferring the minimum hybridization networks from multiple gene trees. The PIRNC algorithm does not rely on structural assumptions. To the best of our knowledge, PIRNC is the first exact algorithm for this formulation. When the number of reticulation events is relatively small (say four or fewer), PIRNC runs reasonably efficient even for moderately large datasets. For building more complex networks, we also develop a heuristic version of PIRNC called PIRNCH. Simulation shows that PIRNCH usually produces networks with fewer reticulation events than those by an existing method.
Monetary policy and long-term real rates

Changes in monetary policy have surprisingly strong effects on forward real rates in the distant future. A 100 basis point increase in the two-year nominal yield on a Federal Open Markets Committee announcement day is associated with a 42 basis point increase in the ten-year forward real rate. This finding is at odds with standard macro models based on sticky nominal prices, which imply that monetary policy cannot move real rates over a horizon longer than that over which all prices in the economy can readjust. Instead, the responsiveness of long-term real rates to monetary shocks appears to reflect changes in term premia. One mechanism that could generate such variation in term premia is based on demand effects due to the existence of what we call yield-oriented investors. We find some evidence supportive of this channel.
The Strong CP Problem and Axions

I describe how the QCD vacuum structure, necessary to resolve the U(1)_A problem, predicts the presence of a PabbrevPparity transformation, TabbrevTtime reversal transformation, and CPabbrevCPcharge conjugation transformation followed by party transformation violating term proportional to the vacuum angle θ. To agree with experimental bounds, however, this parameter must be very small (θ < 10-9). After briefly discussing some other possible solutions to this, so-called, strong CP problem, I concentrate on the chiral solution proposed by Peccei and Quinn which has associated with it a light pseudoscalar particle, the axion. I discuss in detail the properties and dynamics of axions, focusing particularly on invisible axion models where axions are very light, very weakly coupled, and very long-lived. Astrophysical and cosmological bounds on invisible axions are also briefly touched upon.
Interaction of CaO–FeO–SiO2 Slags with Partially Stabilized Zirconia

Calcia- and magnesia-partially-stabilized zirconia samples were corroded under static and dynamic conditions in three slags from the CaO-FeO-SiO[sub 2] system. Low-basicity and high-FeO slags corroded the samples by leaching magnesia from the cubic phase in the specimen, causing its destabilization and ultimate dissolution. However, a higher-basicity slag which proved the most corrosive of the three promoted bulk dissolution of the cubic phase instead, the rate of which was controlled by the thickness of the adjacent slag boundary layer. The levels of sample corrosion both at and below the slag line are used to illustrate the effects of experimental variables, including slag composition, specimen density, and slag motion.
Preparation and reactions of 4-iodobutyl pinacolborate. Synthesis of substituted alkyl and aryl pinacolboronates via 4-iodobutyl pinacolborate utilizing tetrahydrofuran as the leaving group

Iodine reacts with 4,4,5,5-tetramethyl-1,3,2-dioxaborolane (HBpin), under ambient reaction conditions in THF, to form the iodoalkylborate species 2-(4-iodobutoxy)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (4-IboxBpin). Apparently, one-half equivalent of I2 reacts with HBpin to form IBpin in pentanes, which in turn cleaves THF to form the 4-IboxBpin. Alkyl and aryl Grignard reagents, prepared under Barbier conditions, then react with 4-IboxBpin to form the corresponding alkyl and aryl pinacolboronates while reforming and liberating THF as the leaving group.
Comparative Similarity Analysis of Hypersonic Rarefied Gas Flows Near Simple-Shape Bodies

Hypersonic viscous flows near simple-shape bodies (wedge, cone, disk, and plate) have been studied numerically under the conditions of wind-tunnel experiments. The Direct Simulation Monte-Carlo technique has been used to study the influence of similarity parameters (the Reynolds number, temperature factor, specific heat ratio, and viscosity-approximation parameter) on the flow structure near the bodies and on the aerodynamic coefficients in hypersonic streams of air, nitrogen, helium, and argon. The numerical results are in a good agreement with experimental data, which were obtained in a vacuum chamber at low and moderate Reynolds numbers from 0.1 to 200.
The effect of IMF programs on economic growth

Abstract Using a bivariate, dynamic version of the Heckman selection model, we estimate the effect of participation in International Monetary Fund (IMF) programs on economic growth. We find evidence that governments enter into agreements with the IMF under the pressures of a foreign reserves crisis but they also bring in the Fund to shield themselves from the political costs of adjustment policies. Program participation lowers growth rates for as long as countries remain under a program. Once countries leave the program, they grow faster than if they had remained, but not faster than they would have without participation.
Local writhing dynamics

We present an alternative local definition of the writhe of a self-avoiding closed loop which differs from the traditional non-local definition by an integer. When studying dynamics this difference is immaterial. We employ a formula due to Aldinger, Klapper and Tabor for the change in writhe and propose a set of local, link preserving dynamics in an attempt to unravel some puzzles about actin.