cssi/SciSciGPT-SciSciNet huggingface dataset:
Bilateral Ureteral Obstruction Associated With Henoch-Schoenlein Purpura

Renal involvement is common in Henoch-Schoenlein purpura (HSP) and, while ureteral obstruction has been described in patients with the disease, it is rare. We report a female with HSP who developed bilateral ureteral obstruction from peri-ureteral vasculitis and subsequent ureteral ischemia. Hydronephrosis and typical findings on contrast urography indicated the diagnosis.
Functional integration on spaces of connections

Suppose thatGis a compact connected Lie group andP→Mis a smooth principalG-bundle. We define a “cylinder function” on the space A of smooth connections onPto be a continuous complex function of the holonomies along finitely many piecewise smoothly immersed curves inM. Completing the algebra of cylinder functions in the sup norm, we obtain a commutative C*-algebra Fun(A). Let a “generalized measure” on A be a bounded linear functional on Fun(A). We construct a generalized measureμ0on A that is invariant under all automorphisms of the bundleP(not necessarily fixing the baseM). This result extends previous work which assumedMwas real-analytic and used only piecewise analytic curves in the definition of cylinder functions. As before, any graph withnedges embedded inMdetermines a C*-subalgebra of Fun(A) isomorphic toC(Gn), and the generalized measureμ0: Fun(A)→C restricts to the linear functional onC(Gn) given by integration against normalized Haar measure onGn. Our result implies that the group G of gauge transformations acts as unitary operators onL2(A), the Hilbert space completion of Fun(A) in the norm ‖F‖2=μ0(|F|2)1/2. Using “spin networks,” we construct explicit functions spanning the subspaceL2(A/G)⊆L2(A) consisting of vectors invariant under the action of G.
Techniques for Parathyroid Localization with Ultrasound

Four-gland parathyroid exploration has been the gold standard for parathyroid surgery until recently. Emphasis is now placed on minimally invasive and focused parathyroidectomy. In conjunction with functional sestamibi scanning, ultrasonography permits accurate localization of enlarged parathyroid glands in the vast majority of patients with hyperparathyroidism. Consequently, ultrasound technology applied to parathyroid pathology facilitates directed surgical therapy and minimally invasive applications. As such, ultrasonography holds great promise as a tool that enables cost-effective and advanced patient care.
Low Mach Number Limit of Viscous Compressible Magnetohydrodynamic Flows

The relationship between the compressible magnetohydrodynamic flows with low Mach number and the incompressible magnetohydrodynamic flows is investigated. More precisely, the convergence of weak solutions of the compressible isentropic viscous magnetohydrodynamic equations to the weak solutions of the incompressible viscous magnetohydrodynamic equations is proved as the density becomes constant and the Mach number goes to zero; that is, the corresponding incompressible limits are justified when the spatial domain is a periodic domain, the whole space, or a bounded domain.
John M. Wilcox 1925”1983

John Marsh Wilcox, Director of the Stanford Solar Observatory, died while swimming in surf in the Sea of Cortez near Puerto Penasco, Mexico, on October 14, 1983. He was 58 years old. A solar physicist specializing in the study of magnetic fields at the solar surface and in the interplanetary medium, Wilcox authored or coauthored over 100 scientific publications. Over the past decade, working with various associates, Wilcox found that there is a yet unexplained connection between the sector boundaries of the interplanetary magnetic field and the areas of strong vorticity in the circulation of the earth's atmosphere at the lower boundary of the stratosphere. The effect, though small and of changeable magnitude, is of great theoretical interest.
INELASTIC NEUTRON SCATTERING INVESTIGATION OF SPIN WAVES AND MAGNETIC INTERACTIONS IN α-Fe2O3

Spin waves in antiferromagnetic α-Fe2O3 have been studied at temperatures of 240 and 290° K by means of inelastic neutron scattering. We report here the first determination of the acoustical branch throughout the entire Brillouin zone and the first observation of the optical branch. The latter shows little dispersion throughout the zone, and has an energy of 1125° K (97 meV) at the zone centre. At the zone boundaries a gap of 20 to 70° K exists between the two branches. Heisenberg interaction parameters Jm defined through a Hamiltonian were obtained through fitting of the data to theoretical expressions for the dispersion relations. The following values were obtained for the first five nearest neighbours: J1 = 6.0 ± 1.6° K, J2 = 1.6 ± 0.6° K, J3 = −29.7 ± ± 2.0° K, J4 = −23.2 ± 1.0° K and J5 = −1.0 ± 1.0° K. Interactions to farther neighbours were found to be weak. Neutron intensity data were partly invoked in obtaining the interaction parameters, as two sets of parameters could fit the energy data almost equally well, but they predicted different relative intensities for the two branches in certain regions of the reciprocal space. All spin waves of energy larger than 80° K, including the entire optical branch, were found to be unaffected by the Morin spin-flip transition at 261° K temperature. The spin-wave data were used to calculate the sublattice magnetization, the Neel and the Curie-Weiss temperatures, the perpendicular susceptibility at low temperatures and the density of spin-wave state spectrum. [Russian Text Ignored]
Some exact results on tachyon condensation in string field theory

The study of open string tachyon condensation in string field theory can be drastically simplified by making an appropriate choice of coordinates on the space of string fields. We show that a very natural coordinate system is suggested by the connection between the worldsheet renormalization group and spacetime physics. In this system only one field, the tachyon, condenses while all other fields have vanishing expectation values. These coordinates are also well-suited to the study of D-branes as solitons. We use them to show that the tension of the D25-brane is cancelled by tachyon condensation and compute exactly the profiles and tensions of lower dimensional D-branes.
Nanoscale morphology of polyelectrolyte self-assembled films probed by scanning force and near-field scanning optical microscopy

Abstract We applied shear force microscopy, an analog to attractive-mode atomic force microscopy, and near-field scanning optical microscopy (NSOM) to the study of surface roughness and nanoscale morphology in polyelectrolyte self-assembled layers. Our data show that the surface roughness of multilayer films on glass grows linearly with the number of polyelectrolyte bilayers for the first 10 bilayers, and then asymptotes at a surface roughness of 4 nm. The surface of these films is characterized by bumps of 100–500 nm in diameter and 25–50 nm tall. In addition, the size and density of the bumps for each bilayer are uncorrelated to the previous surface. This result is in sharp contrast to what is observed for other self-assembled layer structures, such as metal-phosphonate and Langmuir–Blodgett self-assembly, where the surface roughness linearly increases with the number of layers. Subsurface morphology in thin films was observed via fluorescence NSOM of a dye-doped polyelectrolyte film. The NSOM images show domains of higher and lower fluorescence intensity, which could be assigned to local changes in the film thickness, suggesting that the dye molecules are uniformly distributed within the film. We also show that both the initial and asymptotic surface roughness can be dramatically decreased if the bare glass surface is treated with a high charge-density polyelectrolyte, such as poly(ethyleneimine) (PEI), prior to the bilayer formation. Finally, we observed that if the initial substrate is rough, growth of the polyelectrolyte layers acts to smooth the surface until the equilibrium value is reached.
Duration of molecules in upper quantum states

Values of rate of decay and mean life of atoms and molecules in upper quantum states calculated from data on the intensity of absorption lines.—By combining Fuchtbauer's method of determining from the intensity of absorption lines the probability that a molecule will absorb a quantum of energy, with Einstein's views as to the mechanism of light absorption and emission, the following equation is derived for calculating the rate at which molecules jump from upper to lower quantum states: A21=8πν2/c2N1p1/p2∫0∞αdν where A21 is the chance per unit time that a molecule will jump spontaneously from quantum state 2 to quantum state 1, ν is the frequency of the light emitted in such a jump, p1 and p2 are the a priori probabilities of quantum states 1 and 2, and α is the absorption coefficient of the substance measured under conditions such that N1 is the number of molecules per unit volume in the lower quantum state 1. The integral ∫αdν is to be taken over the total effective width of the absorption line corresponding to the passage of molecules from quantum state 1 to quantum state 2. The mean life τ of molecules which decay from state 2 to state 1 is the reciprocal of A21. Values of A21 and τ are calculated from existing data for the mercury line λ2537, for a number of lines belonging to the alkali doublets, for the iodine line λ5461, and for a very considerable number of lines belonging to the rotation-oscillation spectra of the hydrogen halides. The values obtained agree with the meager data made available by other experimental methods. From these results the following conclusions are drawn. The mean life of molecules and atoms in upper quantum states may vary for different states at least over the range 1 to 10-8 seconds. The rate of decay is not a simple function of the frequency of the emitted light. The rate corresponding to the emission of a line of high frequency may be greater or less than that for a line of lower frequency. The data now available for the alkali doublets 1s-mp1 and 1s-mp2 indicate a higher rate of decay the smaller the change in total quantum number for the line under consideration. The rate of decay from a given mp1 state is m times as great as from the corresponding mp2 state (already stated in another form by Fuchtbauer and Hofmann). In the case of the rotation-oscillation spectra of the hydrogen halides the rate of decay is greater for quantum states with one unit of oscillation and many of rotation, than for those with one unit of oscillation and only a few of rotation; and in the case of different molecules but the same quantum numbers the rate of decay is greater for the molecule with the greater frequency of oscillation. Finally the possibility and method of calculating absolute values of A21 from the Bohr correspondence principle is indicated.
Inter-ring directed ortho lithiation by the 2-pyridyl group in bipyridines

Abstract Kinetically enhanced metallation by the 2-pyridyl group of 2,2′-bipyridine or 2,4′-bipyridine (BPY) in the presence of lithium 2,2,6,6-(tetramethyl)piperidide directs lithiation to the ortho position of the adjacent ring. Representative electrophiles convert the lithiated material to a number of substituted products. The stannylated BPY products were coupled with 3-iodopyridine in the presence of Pd(PPh 3 ) 4 to give two novel terpyridines.
Signal reconstruction from the phase of the bispectrum

The authors present a simple procedure, the bispectrum signal reconstruction (BSR) algorithm, to recover the Fourier phase of a signal from the phase of its bispectrum. By simple analogy, a procedure that recovers the Fourier magnitude of a signal from the magnitude of its bispectrum is also presented. In addition, the authors propose an iterative scheme, the bicepstrum iterative reconstruction algorithm (BIRA), for the reconstruction of a finite impulse response (FIR) sequence from only the phase of its bispectrum, and they demonstrate how some a priori information on the energy of the cepstra coefficients can improve significantly the convergence rate of the algorithm. Both schemes are based on the key observation that the differences of the bispectrum coefficients contain all the information concerning the Fourier phase of the signal, whereas their sums contain the Fourier-magnitude information. >
A Tight Analysis of the Greedy Algorithm for Set Cover

We establish significantly improved bounds on the performance of the greedy algorithm for approximatingset cover. In particular, we provide the first substantial improvement of the 20-year-old classical harmonic upper bound,H(m), of Johnson, Lovasz, and Chvatal, by showing that the performance ratio of the greedy algorithm is, in fact,exactlylnm?lnlnm+?(1), wheremis the size of the ground set. The difference between the upper and lower bounds turns out to be less than 1.1. This provides the first tight analysis of the greedy algorithm, as well as the first upper bound that lies belowH(m) by a function going to infinity withm. We also show that the approximation guarantee for the greedy algorithm is better than the guarantee recently established by Srinivasan for the randomized rounding technique, thus improving the bounds on theintegrality gap. Our improvements result from a new approach which might be generally useful for attacking other similar problems.
Introduction to Geomagnetic Fields

Introduction to Geomagnetic Fields is a textbook for advanced undergraduate and graduate students of geophysics. It explains the natural magnetic fields in and surrounding the Earth that arise from a variety of electric currents. The author clearly presents these different components of the Earth's magnetic field with a minimum of mathematical complexity. Readers are also introduced to the techniques and instrumentation for measuring geomagnetic fields, and to the range of applications for which these measurements are used. This second edition has been fully revised. It has been designed as a textbook for use with semester courses in geomagnetism and includes student exercises at the end of each chapter. Special appendices review relevant mathematical techniques and direct the reader to various journals, books, organizations, and websites where computer programs for geomagnetism may be downloaded.
A SURVEY OF HIGH-CONTRAST STELLAR FLARES OBSERVED BY CHANDRA

The X-ray light curves of pre-main-sequence (PMS) stars can show variability in the form of flares altering a baseline characteristic activity level; the largest X-ray flares are characterized by a rapid rise to more than 10 times the characteristic count rate, followed by a slower quasi-exponential decay. Analysis of these high-contrast X-ray flares enables the study of the innermost magnetic fields of PMS stars. We have scanned the ANCHORS database of Chandra observations of star-forming regions to extend the study of flare events on PMS stars both in sky coverage and in volume. We developed a sample of 30 high-contrast flares out of the 14,000 stars of various ages and masses available in ANCHORS at the start of our study. Applying methods of time-resolved spectral analysis, we obtain the temperatures, confining magnetic field strengths, and loop lengths of these bright, energetic flares. The results of the flare analysis are compared to the Two Micron All Sky Survey and Spitzer data available for the stars in our sample. We find that the longest flare loop lengths (of order several stellar radii) are only seen on stars whose IR data indicates the presence of disks. This suggests that the longest flares maymore » stretch all the way to the disk. Such long flares tend to be more tenuous than the other large flares studied. A wide range of loop lengths are observed, indicating that different types of flares may occur on disked young stellar objects.« less
Transformation-Toughened ZrO2: Correlations between Grain Size Control and Composition in the System ZrO2-Y2O3

The average grain size of ZrO2(+Y, o,) materials sintered at 1400°C was observed to depend significantly on the Y2O3 content. The average grain size decreased by a factor of 4 to 5 for Y2O3 contents between 0.8 and 1.4 mol% and increased at Y2O3 contents of 6.6 mol%. Grain growth control by a second phase is the concept used to interpret these data; compositions with a small grain size lie within the two-phase tetragonal + cubic phase field, and the size of the tetragonal grains is believed to be controlled by the cubic grains. This interpretation suggests that the Y2O3-rich boundary of the two-phase field lies between 0.8 and 1.4 mol% Y2O3. Transformation toughened materials fabricated in this binary system must have a composition that lies within the two-phase field to obtain the small grain size required, in part, to retain the tetragonal toughening agent.
Understanding European Real Exchange Rates

We study good-by-good deviations from the Law-of-One-Price (LOP) for over 1,800 retail goods and services between all European Union (EU) countries for the years 1975, 1980, 1985, and 1990. We find that for each of these years, after we control for differences in income and value-added tax (VAT) rates, there are roughly as many overpriced goods as there are underpriced goods between any two EU countries. We also find that good-by-good measures of cross-sectional price dispersion are negatively related to the tradeability of the good, and positively related to the share of non-traded inputs required to produce the good. We argue that these observations are consistent with a model in which retail goods are produced by combining a traded input with a non-traded input.
Geodesic density tracking with applications to data driven modeling

Many problems in dynamic data driven modeling deals with distributed rather than lumped observations. In this paper, we show that the Monge-Kantorovich optimal transport theory provides a unifying framework to tackle such problems in the systems-control parlance. Specifically, given distributional measurements at arbitrary instances of measurement availability, we show how to derive dynamical systems that interpolate the observed distributions along the geodesics. We demonstrate the framework in the context of three specific problems: (i) finding a feedback control to track observed ensembles over finite-horizon, (ii) finding a model whose prediction matches the observed distributional data, and (iii) refining a baseline model that results a distribution-level prediction-observation mismatch. We emphasize how the three problems can be posed as variants of the optimal transport problem, but lead to different types of numerical methods.
Towards dideoxynucleosides: the silicon approach

Abstract Dixanthanes, formed from vic-diols, can easily be transformed to the corresponding olefins with diphenylsilane in a new, high-yielding radical reaction.
Kinetics of sub-critical bubbles and the electroweak transition

Abstract We investigate the role of large-amplitude sub-critical thermal fluctuations in the dynamics of first-order phase transitions. In particular, we obtain a kinetic equation for the number density of sub-critical fluctuations of the broken-symmetric phase within the symmetric phase, modeled as spherical bubbles, and solve it analytically for temperatures above the critical temperature. We study the approach to equilibrium and obtain the equilibrium distribution of sub-critical bubbles of the unstable phase by examining three possible mechanisms responsible for their removal; their shrinking, their coupling to thermal noise, and by thermal fluctuations of the true vacuum inside them. We show that for sufficiently strong transitions, either the shrinking or the coupling to thermal noise dominates the dynamics. As the strength of the transition weakens we show that sub-critical fluctuations become progressively more important, as a larger fraction of the total volume is occupied by the broken-symmetric phase, until the point where our analytical approach breaks down. Our investigation suggests that pre-transitional phenomena may considerably change the dynamics of sufficiently weak first-order transitions. We apply our results to the standard electroweak transition.
Enalapril Attenuates the Exaggerated Sympathetic Response to Physical Stress in Prenatally Programmed Hypertensive Rats

Adulthood hypertension can be prenatally programmed by maternal dietary protein deprivation. We have shown that the sympathetically mediated pressor response to physical stress is exaggerated in prenatally programmed hypertensive (PPH) rats. The mechanisms underlying this abnormal responsiveness remain undetermined. The renin–angiotensin system is known to affect sympathetic nerve activity. Therefore, the purpose of this study was to determine whether inhibition of the renin–angiotensin system attenuates the enhanced sympathetic and pressor responses to physical stress in PPH rats. Changes in renal sympathetic nerve activity and blood pressure in response to hindlimb contraction, hindlimb stretch, and hindlimb intra-arterial capsaicin administration were assessed in control and PPH rats treated (from age 3 weeks) with either vehicle or the angiotensin-converting enzyme inhibitor enalapril. Conscious resting systolic arterial pressure was significantly greater in PPH rats (142±5 mm Hg) than in control (128±2 mm Hg) after vehicle treatment ( P
Radiatively induced spontaneous symmetry breaking for asymptotically free gauge theories

We investigate the possibility that the symmetry of asymptotically free theories whose effective scalar quartic coupling constants (in the sense of the renormalization group) take on negative values is dynamically spontaneously broken. We find this phenomenon to be common for theories whose scalars transform as the irreducible second-rank tensor representations of $\mathrm{SU}(n)$ and $\mathrm{O}(n)$. The symmetry-breaking pattern is determined by the tree approximation in some cases, by the one-loop approximation in other cases, but for none of these models does it allow for an asymptotically free theory whose $S$-matrix elements are defined. Our dynamical mechanism does provide a natural explanation of superstrong spontaneous symmetry breaking.
Crosstalk and the Evolution of Specificity in Two-Component Signaling

Two-component Signaling (TCS) serves as the dominant signaling modality in bacteria. A typical pathway includes a sensor Histidine Kinase (HK) that phosphorylates a Response Regulator (RR), modulating its activity in response to an incoming signal. Most HKs are bifunctional, acting as both kinase and phosphatase for their substrates. Unlike eukaryotic signaling networks, there is very little crosstalk between bacterial TCS pathways; indeed, adding crosstalk to a pathway can have disastrous consequences for cell fitness. It is currently unclear exactly what feature of TCS necessitates this degree of pathway isolation. In this work we used mathematical models to show that, in the case of bifunctional HKs, adding a competing substrate to a TCS pathway will always reduce response of that pathway to incoming signals. We found that the pressure to maintain cognate signaling is sufficient to explain the experimentally observed “kinetic preference” of HKs for their cognate RRs. These findings imply a barrier to the evolution of new HK-RR pairs, since crosstalk is unavoidable immediately after the duplication of an existing pathway. We characterized a set of “near-neutral” evolutionary trajectories that minimize the impact of crosstalk on the function of the parental pathway. These trajectories predicted that crosstalk interactions should be removed before new input/output functionalities evolve. Analysis of HK sequences in bacterial genomes provided evidence that the selective pressures on the HK-RR interface are different from those experienced by the input domain immediately after duplication. This work thus provides a unifying explanation for the evolution of specificity in TCS networks.
Aeroacoustics of Three-Stream Jets

Results from acoustic measurements of noise radiated from a heated, three-stream, co-annular exhaust system operated at subsonic conditions are presented. The experiments were conducted for a range of core, bypass, and tertiary stream temperatures and pressures. The nozzle system had a fan-to-core area ratio of 2.92 and a tertiary-to-core area ratio of 0.96. The impact of introducing a third stream on the radiated noise for third-stream velocities below that of the bypass stream was to reduce high frequency noise levels at broadside and peak jet-noise angles. Mid-frequency noise radiation at aft observation angles was impacted by the conditions of the third stream. The core velocity had the greatest impact on peak noise levels and the bypass-to-core mass flow ratio had a slight impact on levels in the peak jet-noise direction. The third-stream jet conditions had no impact on peak noise levels. Introduction of a third jet stream in the presence of a simulated forward-flight stream limits the impact of the third stream on radiated noise. For equivalent ideal thrust conditions, two-stream and three-stream jets can produce similar acoustic spectra although high-frequency noise levels tend to be lower for the three-stream jet.
Sensing and Control of Combustion Instabilities in Swirl-Stabilized Combustors Using Diode-Laser Absorption

** † ‡ Thermoacoustic instability and lean blowout (LBO) are monitored in propane/air flames in a swirl-stabilized combustor using a novel tunable diode laser (TDL) sensor for gas temperature using wavelength-scanned laser absorption of two neighboring water vapor transitions near 1.4 μm. Although the gas composition and temperature are not uniform along the sensor line-of-sight, temperature oscillations and fluctuations are clearly identified in the FFT power spectra of the time-resolved data. Detailed experiments are conducted to optimize the position of the sensor line-of-sight in the flame for thermoacoustic instability and LBO sensing. The output of the sensor is used to suppress the thermoacoustic oscillations in a phase-delay feedback control system, and acoustic modulation of the intake air flow suppresses the temperature oscillations by more than 7dB. The low-frequency temperature fluctuations measured by the TDL sensor increase sharply as the flame approaches LBO. The intensity of these low-frequency fluctuations is used to detect the proximity to LBO, and can be used as a control variable for active LBO suppression without knowing the LBO fuel/air ratio limit. The TDL sensor results are compared with traditional pressure and emission sensors, and the TDL sensor is found to offer several advantages including better spatial resolution and insensitivity to background acoustic noise and flame emissions.
Scaling laws for homogeneous turbulent shear flows in a rotating frame

The scaling properties of plane homogeneous turbulent shear flows in a rotating frame are examined mathematically by a direct analysis of the Navier-Stokes equations. It is proved that two such shear flows are dynamically similar if and only if their initial dimensionless energy spectrum E star (k star, 0), initial dimensionless shear rate SK sub 0/epsilon sub 0, initial Reynolds number K squared sub 0/nu epsilon sub 0, and the ration of the rotation rate to the shear rate omega/S are identical. Consequently, if universal equilibrium states exist, at high Reynolds numbers, they will only depend on the single parameter omega/S. The commonly assumed dependence of such equilibrium states on omega/S through the Richardson number Ri=-2(omega/S)(1-2 omega/S) is proven to be inconsistent with the full Navier-Stokes equations and to constitute no more than a weak approximation. To be more specific, Richardson number similarity is shown to only rigorously apply to certain low-order truncations of the Navier-Stokes equations (i.e., to certain second-order closure models) wherein closure is achieved at the second-moment level by assuming that the higher-order moments are a small perturbation of their isotropic states. The physical dependence of rotating turbulent shear flows on omega/S is discussed in detail along with the implications for turbulence modeling.
A mortar segment-to-segment frictional contact method for large deformations

Abstract Contact modeling is still one of the most difficult aspects of non-linear implicit structural analysis. Most 3D contact algorithms employed today use node-on-segment approaches for contacting dissimilar meshes. Two pass node-on-segment contact approaches have the well known deficiency of locking due to over-constraint. Furthermore, node-on-segment approaches suffer when individual nodes slide out of contact at contact surface boundaries or when contacting nodes slide from facet to facet. This causes jumps in the contact forces due to the discrete nature of the constraint enforcement and difficulties in convergence for implicit solution techniques. In a previous work [Comput. Methods Appl. Mech. Engrg., in press], we developed a segment-to-segment contact approach based on the mortar method that was applicable to large deformation mechanics. The approach proved extremely robust since it eliminated the over-constraint which caused “locking” and provided smooth force variations in large sliding. Here, we extend this previous approach in [Comput. Methods Appl. Mech. Engrg., in press] to treat frictional contact problems. The proposed approach is then applied to several challenging frictional contact problems which demonstrate its effectiveness.
Human menopausal gonadotropins: a justifiable therapy in ovulatory women with long-standing idiopathic infertility.

Abstract Long-standing infertility of unknown etiology is currently an indication for in vitro fertilization. Because of the prolonged waiting time, expense, and operative risk, we have treated a group of women with empiric human menopausal gonadotropins/human chorionic gonadotropin before in vitro fertilization. A study group of 97 couples with well-documented, long-standing idiopathic infertility received up to four cycles of empiric human menopausal gonadotropin therapy before in vitro fertilization. This group was compared with a control group of 48 couples who did not receive human menopausal gonadotropin before in vitro fertilization. The 12 (12.4%) conceptions and eight (8.2%) term births resulting from empiric human menopausal gonadotropin therapy in the study group was significantly higher than the number of spontaneous conceptions and births (1%) in the study group (p
Behavior in a shared resource game with cooperative, greedy, and vigilante players

We study a problem of trust in a distributed system in which a common resource is shared by multiple parties. In such naturally information-limited settings, parties are expected to abide by a behavioral protocol that leads to fair sharing of the resource. However, greedy players may defect from a cooperative protocol and achieve a greater than fair share of resources, often without significant adverse consequences to themselves. In this paper, we study the role of a few vigilante (attendant) players who also defect from a cooperative resource-sharing protocol but only in response to perceived greedy behavior. For a simple model of engagement, we demonstrate surprisingly complex dynamics among greedy and vigilante players. We show that the best response function for the greedy-player under our formulation has a jump discontinuity, which leads to conditions under which there is no Nash equilibrium. To study this property, we formulate an exact representation for the greedy player best response function in the case when there is one greedy player, one vigilante player and N − 2 cooperative players. We use this formulation to show conditions under which a Nash equilibrium exists. We also illustrate that in a case when there is no Nash equilibrium, the discrete dynamic system generated from fictitious play will not converge, but will oscillate indefinitely as a result of the jump discontinuity. The case of multiple vigilante and greedy players is studied numerically. Finally, we explore the relationship between fictitious play and the better-response dynamics (gradient descent) and illustrate that this dynamical system can have a fixed point even when the discrete dynamical system arising from fictitious play does not.
The impact of advertising regulation on industry: the cigarette advertising ban of 1971

This article studies the impact of the 1971 TV/radio advertising ban on the cigarette industry. Data indicate that industry advertising spending decreased sharply immediately following the ban but recovered and actually exceeded the preban level within five years. A dynamic oligopoly model of advertising is developed to incorporate two potential explanations. The estimated model fully accounts for the puzzling trend, with 74% of the postban advertising spending increase explained by industry dynamics, and 26% explained by learning. Furthermore, this article uses the new concept of nonstationary oblivious equilibrium to handle intractable state space and accelerate equilibrium computation.
Organic reducing agents. Reduction of electron deficient bromides by 1,2,2,6,6-pentamethylpiperidine (PMP)/mercaptoethanol☆

Abstract 1,2,2,6,6-pentamethylpiperidine (PMP) is shown to be an effective reducing agent for the radical chain conversion of primary bromoesters to the corresponding esters. The problem of inefficient reduction of tertiary bromoesters in these reactions has been overcome by the addition of an alkyl thiol which mediates the hydrogen atom transfer between the two hindered alkyl centers.
Ion-Exchange Behavior of One-Dimensional Linked Dodecaniobate Keggin Ion Materials

Ion-exchange media for cation or anion separations are employed in private industries such as mining, pharmaceutical, and chemical. Government organizations utilize ion-exchange processes for water treatment, environmental remediation and preservation, and nuclear waste treatment. Here, we present an investigation of the ion-exchange behavior of polyoxoniobate materials. Dodecaniobate Keggin ions, [TNb12O40]16− (T = Si, Ge) linked by cationic dimer bridges, [Nb2O2]6+ or [Ti2O2]4+ form a one-dimensional anionic framework, charge-balanced by hydrated Na+ cations. The hydrated sodium resides in interchain tunnels, only loosely associated with the Keggin chains, a geometry that provides rapid exchange kinetics and high exchange capacity. The lattice water is extremely mobile and could not be located on fixed crystallographic positions. Rather, we characterized the water loading by both thermogravimetric studies and computational studies. The LeBail method was used to quantify unit cell change of Keggin chain ...
On the enumeration of some D-optimal designs

Abstract Two matrices with elements taken from the set { - 1 , 1 } are Hadamard equivalent if one can be converted into the other by a sequence of permutations of rows and columns, and negations of rows and columns. In this paper we summarize what is known about the number of equivalence classes of matrices having maximal determinant. We establish that there are 7 equivalence classes for matrices of order 21 and that there are at least 9884 equivalence classes for matrices of order 26. The latter result is obtained primarily using a switching technique for producing new designs from old.
Lipschitz minorants of Brownian motion and Lévy processes

For $$\alpha > 0$$ , the $$\alpha $$ -Lipschitz minorant of a function $$f\!:\!\mathbb{R }\rightarrow \mathbb{R }$$ is the greatest function $$m : \mathbb{R }\rightarrow \mathbb{R }$$ such that $$m \le f$$ and $$|m(s)-m(t)| \le \alpha |s-t|$$ for all $$s,t \in \mathbb{R }$$ , should such a function exist. If $$X=(X_t)_{t \in \mathbb{R }}$$ is a real-valued Levy process that is not pure linear drift with slope $$\pm \alpha $$ , then the sample paths of $$X$$ have an $$\alpha $$ -Lipschitz minorant almost surely if and only if $$| \mathbb{E }[X_1] | < \alpha $$ . Denoting the minorant by $$M$$ , we investigate properties of the random closed set $$\fancyscript{Z} := \{ t \in \mathbb{R }: M_t = X_t \wedge X_{t-} \}$$ , which, since it is regenerative and stationary, has the distribution of the closed range of some subordinator “made stationary” in a suitable sense. We give conditions for the contact set $$\fancyscript{Z}$$ to be countable or to have zero Lebesgue measure, and we obtain formulas that characterize the Levy measure of the associated subordinator. We study the limit of $$\fancyscript{Z}$$ as $$\alpha \rightarrow \infty $$ and find for the so-called abrupt Levy processes introduced by Vigon that this limit is the set of local infima of $$X$$ . When $$X$$ is a Brownian motion with drift $$\beta $$ such that $$|\beta | < \alpha $$ , we calculate explicitly the densities of various random variables related to the minorant.
Runtime FPGA partial reconfiguration

Field-programmable gate arrays (FPGAs) are now being integrated into many space-based applications. FPGAs are being used as replacements for application-specific integrated circuits (ASICs) without considering new options offered by their reprogrammable nature. Runtime partial reconfiguration can potentially reduce the number of devices or the device size, thereby reducing both size and power consumption. A system that requires either transmit or receive capabilities at any given time, but not both, can switch between the two modes in a fraction of a second using partial reconfiguration. The current approach requires that both modes be implemented simultaneously, thereby wasting power and requiring more resources. The idea of adaptively allocating limited FPGA resources is also applicable to hardware-accelerated software-defined radios. The hardware accelerators are loaded into FPGA(s) as they are needed. Partial reconfiguration allows swapping of accelerators much faster than is possible with current methods, and with less disruption to other processes running in parallel. This technology significantly reduces power consumption critical for space and portable ground-based applications of FPGA technology. A software-defined radio was designed with a reprogrammable forward error correction (FEC) block supporting multiple FEC codes to demonstrate one practical use of this technology. This paper provides an overview of the design flow necessary for partial reconfiguration and comments on the additional overhead necessary for creating such a design. In addition, limitations to this emerging technology are outlined.
Immigrant Transnational Organizations and Development: A Comparative Study

This article explores how ninety Colombian, Dominican, and Mexican transnational immigrant organizations pursue philanthropic projects that aid in the development of their country or community of origin. We find that each nationality's context of exit and reception affects the origin, strength, and character of their organizations. We produce “maps” of the interaction of transnational organizations with each country of origin and conduct multivariate regressions to establish determinants of key organizational characteristics, including their degree of formalization and form of creation. Generally, Colombian organizations assume more middle-class forms, Dominican organizations stem largely from politics in the country of origin, and Mexican organizations are primarily hometown associations with greater involvement of the national state. We observe that regardless of nationality, transnational immigrant organizations’ members are older, better-established, and possess above-average levels of education, suggesting that participation in transnational activities and assimilation are not incompatible. The character of proactive activities by each national state are examined. Theoretical implications for immigrant adaptation and community/national development are discussed.
On Borel fixed ideals generated in one degree

Abstract We construct a shellable polytopal cell complex that supports a minimal free resolution of a Borel fixed ideal, which is Borel generated by just one monomial in S = k [ x 1 , x 2 , … , x n ] ; this includes the case of powers of the homogeneous maximal ideal ( x 1 , x 2 , … , x n ) as a special case. In our most general result we prove that for any Borel fixed ideal I generated in one degree, there exists a polytopal cell complex that supports a minimal free resolution of I.
Synthesis and Electrical Properties of Dense Ce0.9Gd0.1O1.95 Ceramics

Uniform spherical powders of Ce 0.9 Gd 0.1 O 1.95 with an average diameter of 250 nm were obtained at 700°C from a sol-gel process of mixing nitrates and ethylene glycol. Broadening of the X-ray peaks of the fluorite structure reveals a small crystallite size within the powders. Sintering in air of pressed pellets of the powders at 1585°C gives ceramics of 99% theoretical density with grain sizes 1-10 μm and a cubic unit cell a = 5.422 ± 0.034 A. The electrical conductivity σ = σ o + σ e has two components. In air or argon, the electronic component σ e is negligible and the oxide-ion conductivity σ o is not described by a classical Arrhenius equation; a pronounced curvature at T T * has been observed in the Arrhenius plot of the bulk conductivity. The system could be modeled by a condensation of mobile oxygen vacancies into ordered clusters below a temperature T* 583 ± 45°C and a motional enthalpy ΔH m = 0.63 ± 0.01 eV for the vacancies. A measured trapping energy ΔH t (I - T/T * ) has ΔH t = 0.19 ± 0.01 eV = 2.57kT*. In a reducing atmosphere, σ e exhibits a small-polaron motional enthalpy ΔH P = 0.40 ± 0.08 eV for transfer of a 4f electron from a Ce 3+ to a Ce 4+ ion and a ΔH p + ΔH pt = 0.51 ± 0.04 eV at T < T*.
A learning optimizer for a federated database management system

Anfrageoptimierer in modernen Datenbanksystemen (DBS) verwenden ein Kostenmodell, um fur eine Anfrage einen effizienten Zugriffsplan aus der Menge aller moglichen Zugriffsplane auszuwahlen. Die Genauigkeit, mit der diese Kosten geschatzt werden, hangt stark davon ab, wie genau Statistiken uber die Datenverteilung die ihnen zugrunde liegenden Daten modellieren. Veraltete Statistiken, oder ungultige Annahmen im statistischen Modell, fuhren haufig zur Auswahl suboptimaler Zugriffsplane und dadurch zu Defiziten bei der Ausfuhrungsgeschwindigkeit von Datenbankanfragen. Foderierte Systeme mussen auf dem koordinierenden DBS Statistiken uber verteilte Daten unterhalten, um effiziente Zugriffsplane zu entwickeln, wenn Daten aus verschiedenen Datenquellen zusammengefuhrt werden. Fehlerhafte Statistiken verursachen in diesem Fall schlechte Lastenverteilung sowie zusatzlichen Kommunikationsaufwand und Netzlast. Die Synchronisation dieser zusatzlichen Statistiken mit den Statistiken der entfernten Datenquellen ist problematisch, da Datenquellen vollig unabhangig voneinander sind und ihre Statistiken eventuell nicht externalisieren oder inkompatible bzw. andere statistische Modelle verwenden als das koordinierende DBS. Im folgenden zeigen wir eine Erweiterung der Feedback-Schleife von DB2s lernendem Optimierer (LEO) auf foderierte Architekturen, die es LEO ermoglicht, automatisch Statistiken uber Daten auf entfernten Datenquellen zu lernen und zu verwalten. Wir diskutieren mehrere Moglichkeiten, Feedback fur foderierte Anfragen zu erhalten und stellen einen Losung vor, die lokales Feedback verwendet, und einen Stichprobenprozess (statistical sampling) zu steuren, der die benotigten entfernten Daten basierend auf dem Feedback effizient ermittelt. Mittels einer detaillierten Leistungsanalyse der vorgestellten Moglichkeiten im Rahmen einer Fallstudie belegen wir, dass der potenzielle Geschwindigkeitszuwachs fur Datenbankanfragen sehr hoch ist, wahrend die Zusatzbelastung durch LEO in moderaten Grenzen liegt.
Hypoellipticity for filtering problems of partially observable diffusion processes

We prove that under Hormander’s type conditions on the coefficients of the unobservable component of a partially observable diffusion process the filtering density is infinitely differentiable and can be represented as the integral of an infinitely differentiable kernel against the prior initial distribution. These results are derived from more general results obtained for SPDEs. One of the main novelties of the paper is the existence and smoothness of the kernel, another one is that we allow the coefficients of our partially observable process to be just measurable with respect to the time variable and Lipschitz continuous with respect to the observation variable.
See an object, hear an object file: Object correspondence transcends sensory modality

An important task of perceptual processing is to parse incoming information into distinct units and to keep track of those units over time as the same, persisting representations. Within the study of visual perception, maintaining such persisting object representations is helped by “object files”—episodic representations that store (and update) information about objects' properties and track objects over time and motion via spatiotemporal information. Although object files are typically discussed as visual, here we demonstrate that object–file correspondence can be computed across sensory modalities. An object file can be initially formed with visual input and later accessed with corresponding auditory information, suggesting that object files may be able to operate at a multimodal level of perceptual processing.
Permeability and Effective Pore Pressure of Shales

Laboratory-derived permeability and pore-pressure data obtained for Wellington and Pierre shales are used to describe swelling pressure, and spalling types of wellbore instability. Tests showed that increased pore pressures can lead to wellbore failure. The laboratory pore-pressure information developed displays a time-dependent swelling process followed by a Darcy type of flow. A total aqueous chemical potential concept is presented that describes the driving potentials that operate during both phases of flow. Experimental methods are presented to determine the storage of water shale during the swelling phase and the permeabilities with steady-state-flow and transient-flow techniques. Permeability values measured under effective stresses up to 8,000 psi show the Wellington shale to have values as low as 0.30 [times] 10[sup [minus]6] md.
Silicon nanowires as efficient thermoelectric materials

Thermoelectric materials, capable of converting a thermal gradient to an electric field and vice versa, could be useful in power generation and refrigeration. But the fabrication of the available high-performance thermoelectric materials is not easily scaled up to the volumes needed for large-scale heat energy scavenging applications. Nanostructuring improves thermoelectric capabilities of some materials, but good thermoelectric materials tend not to take readily to nanostructuring. How about silicon? It can be processed on a large scale but has poor thermoelectric properties. Two groups now show that silicon's thermoelectric properties can be vastly improved by structuring it into arrays of nanowires and carefully controlling nanowire morphology and doping. So with more development, silicon may have potential as a thermoelectric material. Thermoelectric materials interconvert thermal gradients and electric fields for power generation or for refrigeration1,2. Thermoelectrics currently find only niche applications because of their limited efficiency, which is measured by the dimensionless parameter ZT—a function of the Seebeck coefficient or thermoelectric power, and of the electrical and thermal conductivities. Maximizing ZT is challenging because optimizing one physical parameter often adversely affects another3. Several groups have achieved significant improvements in ZT through multi-component nanostructured thermoelectrics4,5,6, such as Bi2Te3/Sb2Te3 thin-film superlattices, or embedded PbSeTe quantum dot superlattices. Here we report efficient thermoelectric performance from the single-component system of silicon nanowires for cross-sectional areas of 10 nm × 20 nm and 20 nm × 20 nm. By varying the nanowire size and impurity doping levels, ZT values representing an approximately 100-fold improvement over bulk Si are achieved over a broad temperature range, including ZT ≈ 1 at 200 K. Independent measurements of the Seebeck coefficient, the electrical conductivity and the thermal conductivity, combined with theory, indicate that the improved efficiency originates from phonon effects. These results are expected to apply to other classes of semiconductor nanomaterials.