cssi/SciSciGPT-SciSciNet huggingface dataset:
Development of blood coagulation--a fetal lamb model.

Summary: To study the normal development of blood coagulation factor activities in a growing fetus while avoiding the effects of labor and delivery, a chronic fetal lamb model was developed in which serial blood samples from 10 fetuses were studied during the third trimester of pregnancy and 24 hr after birth. Under operating room conditions with sterile technique, a polyethylene catheter to which heparin had been bound to both internal and external surfaces was inserted into the femoral artery of the fetus. The catheter was brought out through a skin pouch to the side of the ewe and enclosed in a zip lock bag. Blood samples were withdrawn from the catheter three times each week for measurement of coagulation factor activities. Levels of coagulation factor activities at birth in noncatheterized animals were not different from those found in catheterized animals except for factor IX activity which was 12% higher in the catheterized animals (0.02 < P < 0.05). The patterns of development for each of the coagulation factors were similar in all 10 animals studied. Fibrinogen, prothrombin, and factor VII show a decrease in activity early in the last trimester of pregnancy whereas other factors V, VIII, IX, X, XI, XII, and XIII show a gradual increase in activity throughout the last trimester of pregnancy. Both factors VIII and IX show a significant increase in activity (23% factor VIII and 12% factor IX) associated with the process of delivery. The levels of coagulation factor activities at birth in the lamb relative to adult sheep normals are similar to those found in humans with the exception of factor XIII. Factor XIII is at normal levels in the newborn lamb and is reported to be at levels approximately 50% of the adult level in human infants. Speculation: The development of a chronic fetal lamb preparation has allowed the construction of developmental patterns for coagulation factor activities throughout the last trimester of pregnancy. Further studies into the biology of the changes in coagulation factor activities observed and the influences of such stresses as hypoxemia and premature delivery should enhance our understanding of the bleeding neonate.
Exact de Rham Sequences of Spaces Defined on Macro-Elements in Two and Three Spatial Dimensions

This paper proposes new finite element spaces that can be constructed for agglomerates of standard elements that have certain regular structure. The main requirement is that the agglomerates share faces that have closed boundaries composed of 1-d edges. The spaces resulting from the agglomerated elements are subspaces of the original de Rham sequence of $H^1$-conforming, $H(\mathbf{curl})$-conforming, $H(\mathbf{div})$-conforming, and piecewise constant spaces associated with an unstructured “fine” mesh. The procedure can be recursively applied so that a sequence of nested de Rham complexes can be constructed. As an illustration we generate coarser spaces from the sequence corresponding to the lowest-order Nedelec spaces, lowest-order Raviart-Thomas spaces, and for piecewise linear $H^1$-conforming spaces, all in three dimensions. The resulting $V$-cycle multigrid methods used in preconditioned conjugate gradient iterations appear to perform similar to those of the geometrically refined case.
S Matrix for the One-Dimensional N -Body Problem with Repulsive or Attractive δ -Function Interaction

For $N$ particles with equal mass, interacting with repulsive or attractive $\ensuremath{\delta}$-function interaction of the same strength, the $S$ matrix is explicitly given and shown to be symmetrical and unitary. The incoming and outgoing states may consist of bound compounds as well as single particles. The momenta of the particles and compounds are not changed in the scattering, but particles are exchanged, such as $ABC+DE\ensuremath{\rightarrow}ADC+BE$. Only distinguishable particles are considered.
Reverse Mathematics and Uniformity in Proofs without Excluded Middle

We show that when certain statements are provable in subsystems of constructive analysis using intuitionistic predicate calculus, related sequential statements are provable in weak classical subsystems. In particular, if a $\Pi^1_2$ sentence of a certain form is provable using E-HA${}^\omega$ along with the axiom of choice and an independence of premise principle, the sequential form of the statement is provable in the classical system RCA. We obtain this and similar results using applications of modified realizability and the Dialectica interpretation. These results allow us to use techniques of classical reverse mathematics to demonstrate the unprovability of several mathematical principles in subsystems of constructive analysis.
Centering in Dynamic Semantics

Centering theory posits a discourse center, a distinguished discourse entity that is the topic of a discourse. A simplified version of this theory is developed in a Dynamic Semantics framework. In the resulting system, the mechanism of center shift allows a simple, elegant analysis of a variety of phenomena involving sloppy identity in ellipsis and "paycheck pronouns".
Trivializations of differential cocycles

Associated to a differential character is an integral cohomology class, referred to as the characteristic class, and a closed differential form, referred to as the curvature. The characteristic class and curvature are equal in de Rham cohomology, and this is encoded in a commutative square. In the Hopkins–Singer model, where differential characters are equivalence classes of differential cocycles, there is a natural notion of trivializing a differential cocycle. In this paper, we extend the notion of characteristic class, curvature, and de Rham class to trivializations of differential cocycles. These structures fit into a commutative square, and this square is a torsor for the commutative square associated to characters with degree one less. Under the correspondence between degree two differential cocycles and principal circle bundles with connection, we recover familiar structures associated to global sections.
Correlation Statistics of Spectrally Varying Quantized Noise

I calculate the noise in the measured correlation functions and spectra of digitized, noiselike signals. In the spectral domain, the signals are drawn from a Gaussian distribution with variance that depends on frequency. Nearly all astrophysical signals have noiselike statistics of this type, many with important spectral variations. Observation and analysis of such signals at millimeter and longer wavelengths typically involves sampling in the time domain and digitizing the sampled signal. (Quantum mechanical effects, not discussed here, are important at infrared and shorter wavelengths.) The digitized noise is then correlated to form a measured correlation function, which is then Fourier transformed to produce a measured spectrum. When averaged over many samples, the elements of the correlation function and of the spectrum follow Gaussian distributions. For each element, the mean of that distribution is the deterministic part of the measurement. The standard deviation of the Gaussian is the noise. Here I calculate that noise as a function of the parameters of digitization. The noise of the correlation function is related to the underlying spectrum by constants that depend on the digitization parameters. Noise affects variances of elements of the correlation function and covariances between them. In the spectral domain, noise also produces variances and covariances. I show that noise is correlated between spectral channels for digitized spectra and calculate the correlation. These statistics of noise are important for the understanding of signals sampled with very high signal-to-noise ratio, or signals with rapidly changing levels such as pulsars.
Field-theoretic approach to the properties of the solid state

Abstract The techniques of quantum field theory are used to investigate the thermodynamic ion displacement correlation function—or Green's function of the phonon field—in a crystal and especially in a metal. The structure of thermodynamic Green's functions is outlined and the method for solving for them at finite temperature is fully discussed. The analytic structure of the phonon Green's function is then considered. This function is shown to be bounded and invertible everywhere off the real axis; a spectral form is derived for its inverse. The symmetries imposed by the point group of the crystal are then discussed. Assuming small ionic oscillations, we find the inverse of the phonon Green's function as a linear function of the electronic contribution to the dielectric response function of the metal. This dielectric function is shown to be simply related to the longitudinal part of the conductivity tensor that gives the response of the electrons to the effective electric field in the metal. The assumption of translational invariance then leads to an explicit expression for the phonon Green's function in terms of this conductivity. The deformations in the lattice induced by an arbitrarily time varying external force are calculated in terms of the retarded phonon Green's function. In the static long wavelength limit the phonon Green's function yields the macroscopic elastic constants of the crystal. Their relation to the conductivity is exhibited, and several elastic constants are estimated. We also see that the complete phonon spectrum and the lifetimes of the phonon states may be calculated from this Green's function. A relation between the long wavelength acoustic attenuation in metals and the de conductivity is derived, which is in good agreement with recent experiments. Furthermore, the ions in a metal are shown to have a high-frequency oscillation along with the electrons, at essentially the electron plasma frequency.
Gaussian Peaks and Clusters of Galaxies

We develop and test a method to compute mass and autocorrelation functions of rich clusters of galaxies from linear density fluctuations, based on the formalism of Gaussian peaks. The essential, new ingredient in the current approach is a simultaneous and unique fixture of the size of the smoothing window for the density field, rf, and the critical height for collapse of a density peak, δc, for a given cluster mass (enclosed within the sphere of a given radius rather than the virial radius, which is hard to measure observationally). Of these two parameters, rf depends on both the mass of the cluster in question and Ω, whereas δc is a function of only Ω and Λ. These two parameters have formerly been treated as adjustable and approximate parameters. Thus, for the first time, the Gaussian peak method (GPM) becomes unambiguous, and more importantly, accurate, as is shown here. We apply this method to constrain all variants of the Gaussian cold dark matter (CDM) cosmological model using the observed abundance of local rich clusters of galaxies and the microwave background temperature fluctuations observed by COBE. The combined constraint fixes the power spectrum of any model to ~10% accuracy in both shape and overall amplitude. To set the context for analyzing CDM models, we choose six representative models of current interest, including an Ω0 = 1 tilted cold dark matter model, a mixed hot and cold dark matter model with 20% mass in neutrinos, two lower density open models with Ω0 = 0.25 and Ω0 = 0.40, and two lower density flat models with (Ω0 = 0.25, Λ0 = 0.75) and (Ω0 = 0.40, Λ0 = 0.60). This suite of CDM models should bracket any CDM model that is currently viable. The parameters of all these models are also consistent with a set of other constraints, including the Hubble constant, the age of the universe and the light-element nucleosynthesis with Ωb chosen to maximize the viability of each model with respect to the observed gas fraction in X-ray clusters.
Synthesis and Fluoride-Promoted Wittig Rearrangements of α-Alkoxysilanes

Lewis acid-catalyzed reaction of allyl and benzyl trichloroacetimidates with α-silyl alcohols was found to be a general method for the synthesis of α-alkoxysilanes. Upon exposure to CsF, these α-alkoxysilanes could be made to undergo [2,3]-Wittig rearrangement with an efficiency similar to that realized by the analogous but inherently more toxic α-alkoxystannanes.
THE INTERACTION OF NEW AND OLD MAGNETIC FLUXES AT THE BEGINNING OF SOLAR CYCLE 23

The 11 yr cycle of solar activity follows Hale's law by reversing the magnetic polarity of leading and following sunspots in bipolar regions during the minima of activity. In the 1996-1997 solar minimum, most solar activity emerged in narrow longitudinal zones—"active longitudes" but over a range in latitude. Investigating the distribution of solar magnetic flux, we have found that the Hale sunspot polarity reversal first occurred in these active zones. We have estimated the rotation rates of the magnetic flux in the active zones before and after the polarity reversal. Comparing these rotation rates with the internal rotation inferred by helioseismology, we suggest that both "old" and "new" magnetic fluxes were probably generated in a low-latitude zone near the base of the solar convection zone. The reversal of active region polarity observed in certain longitudes at the beginning of a new solar cycle suggests that the phenomenon of active longitudes may give fundamental information about the mechanism of the solar cycle. The nonrandom distribution of old-cycle and new-cycle fluxes presents a challenge for dynamo theories, most of which assume a uniform longitudinal distribution of solar magnetic fields.
How investment bankers determine the offer price and allocation of new issues

Abstract We investigate how investment bankers use indications of interest from their client investors to price and allocate new issues. We model the process as an auction constructed to induce asymmetrically informed investors to reveal what they know to the underwriter. The analysis yields a number of empirical implications, including that new issues will be underpriced and that distributional priority will be given to an underwriter's regular investors. We also find that tension between an underwriter's propensity to presell an issue and an issuing firm's desire to obtain maximum proceeds affects the type of underwriting contract chosen.
Information preserving image compression for archiving NMR images.

Abstract This paper presents a result on information preserving compression of NMR images for the archiving purpose. Both Lynch-Davisson coding and linear predictive coding have been studied. For NMR images of 256 × 256 × 12 resolution, the Lynch-Davisson coding with a block size of 64 as applied to prediction error sequences in the Gray code bit planes of each image gave an average compression ratio of 2.3:1 for 14 testing images. The predictive coding with a third order linear predictor and the Hulffman encoding of the prediction error gave an average compression ratio of 3.1:1 for 54 images under test, while the maximum compression ratio achieved was 3.8:1. This result is one step further toward the improvement, albeit small, of the information preserving image compression for medical applications.
Apodized phase mask coronagraphs for arbitrary apertures

Context. With a clear circular aperture, the vortex coronagraph perfectly cancels an on-axis point source and offers a 0.9 or 1.75λ/D inner working angle for topological charge 2 or 4, respectively. Current and near-future large telescopes are on-axis, however, and the diffraction effects of the central obscuration, and the secondary supports are strong enough to prevent the detection of companions 10−3–10−5 as bright as, or fainter than, their host star. Aims. Recent advances show that a ring apodizer can restore the performance of this coronagraph by compensating for the diffraction effects of a circular central obscuration in a 1D modeling of the pupil. Our aim is to extend this work and design optimal apodizers for arbitrary apertures in 2D in order to tackle the diffraction effects of the spiders and other noncircular artifacts in the pupil. Methods. We fold this analytical result into a numerical optimization scheme that yields hybrid coronagraph designs that combine the advantages of the vortex coronagraph (small in IWA) and of shaped pupils coronagraphs (robustness to central obscuration and pupil asymmetric structures). The transmission of the apodizer is maximized, while constraints are set on the extremum values of the electric field that is computed in chosen regions of the Lyot plane through closed form expressions derived even for topological charges. Optimal apodizers are computed for topological charges 2 and 4 vortex coronagraphs and for telescope apertures with 10–30% central obscurations and 0%, 0.5%, and 1% thick spiders. Results. We put the results of our numerical optimizations in perspective with the analytical solutions and show that our apodizations converge to the ring apodizations. We then characterize the impacts of the obscuration ratio and the thickness of the spiders on the throughput and the IWA. For the apodized charge-2 vortex coronagraph the throughputs are slightly below those of the ring apodized vortex coronagraph, and the inner working angle is mostly unaffected by the apodization. The throughputs of the apodizers for the charge-4 vortex coronagraph are higher than those of the ring apodized vortex coronagraph. This effect increases with the obscuration ratio, though the inner working angle does, too, and it ranges between 2 and 3λ/D. Conclusions. The results presented in this paper show that high contrast at small inner working angles can be obtained with a vortex coronagraph for on-axis telescopes, in spite of the presence of a secondary mirror and its secondary support structures.
Defensive industrial marketing strategies

Abstract This study provides a framework for industrial product managers to select defensive marketing strategies for products facing competitive attack. The proposed model is based on Hauser and Shugan's Defender model. It can be used by marketing decision makers to assess the impact of competitive attack on the firm's shares and contributions, as well as the effects of a range of possible defensive maneuvers. It therefore can serve as an effective model for planning response strategies. An actual (disguised) real-life application of the model to an industrial-product situation is presented and discussed.
Effects of Morphology and Electronic Structure on the Catalysis of Zeolite Encaged Palladium Particles

Abstract After calcination of ion exchanged Pd/Nay at 500°C, the Pd 2+ ions have lost their ligands and are located in sodalite cages, but after calcination at 250° Pd(NHY 3 ) 2+2 ions are present in supercages. Reduction leads to Pd atoms in sodalite cages or to Pd particles in supercages. An important difference between these cases is due to the co-product of hydrogen reduction: NH 4 + ions or protons. Probing these catalysts with the conversion of neopentane shows that Pd particle morphology has only a minor influence on the rate of conversion, but the presence of protons has a marked effect, increasing the activity per site by two orders of magnitude. This result is tentatively ascribed to electron deficient [Pd n -H x ] x+ clusters as superactive sites.
Zeolite Y adsorbents with high vapor uptake capacity and robust cycling stability for potential applications in advanced adsorption heat pumps

Modular and compact adsorption heat pumps (AHPs) promise an energy-efficient alternative to conventional vapor compression based heating, ventilation and air conditioning systems. A key element in the advancement of AHPs is the development of adsorbents with high uptake capacity, fast intracrystalline diffusivity and durable hydrothermal stability. Herein, the ion exchange of NaY zeolites with ingoing Mg2+ ions is systematically studied to maximize the ion exchange degree (IED) for improved sorption performance. It is found that beyond an ion exchange threshold of 64.1%, deeper ion exchange does not benefit water uptake capacity or characteristic adsorption energy, but does enhance the vapor diffusivity. In addition to using water as an adsorbate, the uptake properties of Mg,Na-Y zeolites were investigated using 20 wt.% MeOH aqueous solution as a novel anti-freeze adsorbate, revealing that the MeOH additive has an insignificant influence on the overall sorption performance. We also demonstrated that the labscale synthetic scalability is robust, and that the tailored zeolites scarcely suffer from hydrothermal stability even after successive 108-fold adsorption/desorption cycles. The samples were analyzed using N2 sorption, 27Al/29Si MAS NMR spectroscopy, ICP-AES, dynamic vapor sorption, SEM, Fick's 2nd law and D-R equation regressions. Among these, close examination of sorption isotherms for H2O and N2 adsorbates allows us to decouple and extract some insightful information underlying the complex water uptake phenomena. This work shows the promising performance of our modified zeolites that can be integrated into various AHP designs for buildings, electronics, and transportation applications.
Systematic Receiver Function Analysis of the Moho Geometry in the Southern California Plate-Boundary Region

We investigate the geometry of the Moho interface in the southern California region including the San Andreas fault (SAF), San Jacinto fault zone (SJFZ), Elsinore fault (EF) and Eastern California Shear Zone with systematic analysis of receiver functions. The data set consists of 145 teleseismic events recorded at 188 broadband stations throughout the region. The analysis utilizes a 3D velocity model associated with detailed double-difference tomographic results for the seismogenic depth section around the SAF, SJFZ, and EF combined with a larger scale community model. A 3D ray tracing algorithm is used to produce effective 1D velocity models along each source-receiver teleseismic ray. Common Conversion Point (CCP) stacks are calculated using the set of velocity models extracted for each ray. The CCP stacks are analyzed with volumetric plots, maps of maximum CCP stack values, and projections along profiles that cross major faults and other features of interest. The results indicate that the Moho geometry in the study area is very complex and characterized by large prominent undulations along the NE–SW direction. A zone of relatively deep Moho (~35–40 km) with overall N–S direction crosses the SAF, SJFZ, and EF. A section of very shallow Moho (~10 km) below and to the SE of the Salton Trough, likely associated with a young oceanic crust, produces large Moho offsets at its margins. Locations with significant changes of Moho depth appear to be correlated with fault complexity in the brittle crust. The observations also show vertical Moho offsets of ~8 km across the SAF and SJFZ close to Cajon pass, and sections with no clear Moho phase underneath Cajon pass and adjacent to the SJFZ near Anza likely produced by complex local velocity structures in the brittle upper crust. These features are robust with respect to various parameters of the analysis procedure.
Bit-level analysis of an SRT divider circuit

It is impractical to verify multiplier or divider circuits entirely at the bit-level using ordered binary decision diagrams (BDDs), because the BDD representations for these functions grow exponentially with the word size. It is possible, however, to analyze individual stages of these circuits using BDDs. Such analysis can be helpful when implementing complex arithmetic algorithms. As a demonstration, we show that Intel could have used BDDs to detect erroneous lookup table entries in the Pentium floating point divider. Going beyond verification, we show that bit-level analysis can be used to generate a correct version of the table.
Does the Study of Business Reduce the Likelihood of Committing Insider Trading

Abstract In this study, 347 students at two Christian liberal arts schools and a state university completed a survey after watching a clip from the 1987 film Wall Street. The survey was given to 347 students. Seniors were less likely to respond that they would commit insider trading than were freshmen, and students attending the Christian liberal arts schools, compared with students at the state university, were less likely to respond that they would commit insider trading.
Reciprocal State and Local Airport Spending Spillovers and Symmetric Responses to Cuts and Increases in Federal Airport Grants

How states and localities react to federal airport grant cuts is a question of increasing importance, especially in light of recent congressional funding reauthorization debates. This study finds that states and localities behave in the way public finance theory predicts. The magnitude of an airport spending change is the same (but in opposite directions) for a cut and an increase in airport grants. Thus, the flypaper effect operates in both directions. Spillovers arising from airport spending are also considered. With the hub and spoke structure of the U.S. air transportation system, a spending increase on airports experiencing major time delays confers spillover benefits on individuals in other states in the form of travel time savings from decreased congestion. These spillovers are reciprocal. There is significant evidence of such interdependencies, and an individual state raises airport spending by between 50 and 60 cents when other states increase airport spending by 1 dollar.
Codes on Graphs: Duality and MacWilliams Identities

A conceptual framework involving partition functions of normal factor graphs is introduced, paralleling a similar recent development by Al-Bashabsheh and Mao. The partition functions of dual normal factor graphs are shown to be a Fourier transform pair, whether or not the graphs have cycles. The original normal graph duality theorem follows as a corollary. Within this framework, MacWilliams identities are found for various local and global weight generating functions of general group or linear codes on graphs; this generalizes and provides a concise proof of the MacWilliams identity for linear time-invariant convolutional codes that was recently found by Gluesing-Luerssen and Schneider. Further MacWilliams identities are developed for terminated convolutional codes, particularly for tail-biting codes, similar to those studied recently by Bocharova, Hug, Johannesson, and Kudryashov.
Photographic exploration of Mars with solar- electric propulsion.

Photographic mapping of Martian surface with electrically propelled solar-powered photographic spacecraft placed into near polar orbit
A feature selection framework for text filtering

We present a new framework for local feature selection in text filtering. In this framework, a feature set is constructed per category by first selecting a set of terms highly indicative of membership (positive set) and another set of terms highly indicative of nonmembership (negative set), and then combining these two sets. This feature selection framework not only unifies several standard feature selection methods, but also facilitates the proposal of a new method that optimally combines the positive and negative sets. The experimental comparison between the proposed method and standard methods was conducted on six feature selection metrics: chi-square, correlation coefficient, odds ratio, GSS coefficient and two proposed variants of odds ratio and GSS coefficient: OR-square and GSS-square respectively. The results show that the proposed feature selection method improves text filtering performance.
Capture and containment of the positron beam in the APS injector linac

The authors describe the positron-capture solenoid and F0D0 system for the 450-MeV positron injector linac of the 7-GeV Advanced Photon Source (APS) storage ring at Argonne National Laboratory. A nonlinear beam optics study of the positron-capture solenoid following the positron converter is performed. Based upon an analytical expression of the magnetic fields, the phase space acceptance of the positron-capture solenoid is obtained. The detailed F0D0 structure of the positron-focusing quadrupoles is also discussed. >
Compatible Measures and Merging

Two measures, μ and μI, are updated as more information arrives. If with μ-probability 1, the predictions of future events according to both measures become close, as time passes, we say that μI merges to μ. Blackwell and Dubins Blackwell, D., L. Dubins. 1962. Merging of opinions with increasing information. Ann. Math. Statist.38 882--886. showed that if μ is absolutely continuous with respect to μI then μI merges to μ. Restricting the definition to prediction of near future events and to a full sequence of times yields the new notion of almost weak merging AWM, presented here. We introduce a necessary and sufficient condition and show many cases with no absolute continuity that exhibit AWM. We show, for instance, that the fact that μI is diffused around μ implies AWM.
Cluster winds blow along supercluster axes

Within Abell galaxy clusters containing wide-angle tailed (WAT) radio sources, there is evidence of a `prevailing wind' which directs the WAT jets. We study the alignment of WAT jets and nearby clusters to test the idea that this wind may be a fossil of drainage along large-scale supercluster axes. We also test this idea with a study of the alignment of WAT jets and supercluster axes. Statistical tests indicate no alignment of WAT jets towards nearest neighbour clusters, but do indicate approximately 98 per cent confidence in alignment with the long axis of the supercluster in which the cluster lies. We find a preferred scale for such superclusters of order 25 h-1 Mpc.
User Interaction Design for Secure Systems

The security of any system that is configured or operated by human beings depends on the information conveyed by the user interface, the decisions of the users, and the interpretation of their actions. This paper establishes some starting points for reasoning about security from a user-centred perspective: it proposes to model systems in terms of actors and actions, and introduces the concept of the subjective actor-ability state. Ten principles for secure interaction design are identified; examples of real-world problems illustrate and justify the principles.
Public Health and Public Goods

It has become increasingly difficult to distinguish public health (and public health ethics) from tangentially related fields like social work. I argue that we should reclaim the more traditional conception of public health as the provision of health-related public goods. The public goods account has the advantage of establishing a relatively clear and distinctive mission for public health. It also allows a consensus of people with different comprehensive moral and political commitments to endorse public health measures, even if they disagree about precisely why they are desirable.
The 1,5-Disubstituted Tetrazole Ring as a cis -Amide Bond Surrogate

Proline occupies a special role among those amino acids incorporated into peptides and proteins by the normal ribosomal pathways, since it is the only residue that leads to an N-alkyl amide bond. In peptide natural products that often have special biosynthetic pathways or unusual posttranslational modifications, N-methyl amino acids are common and may play a special role because of their conformational properties, including their proclivity for cis-trans isomerism of the amide bond. Numerous peptides with important biological activities, such as cyclosporin and didemnin, contain N-methyl amino acids. Cis-trans isomerism of the N-alkyl amide bond involving the amino group can readily be observed (1) in the NMR of proline and N-methyl amino acid-containing peptides. In the case of angiotensin and thyroliberin (TRH) analogs, the quantity of cis-isomer in aqueous solution was correlated (2) with the biological activity. This suggested that the cis-isomer might be the one bound to the receptor and responsible for the observed biological activity. Bairaktari et al. (3) have reported that the normal amide bond between an He and Lys residues in the linear peptide, bombolitin, has the cis-conformation when bound to phospholipid micelles. In protei0n crystal structures, cis-amide bond conformations are occasionally observed for the normal, nonalkylated amide bond. A cis-amide bond predisposes the peptide for a reverse turn, a so-called Type VI β-turn. Brandl and Deber (4) have proposed that cis-trans isomerism of proline residue might play a role in transduction of transmembrane proteins.
Effects of a High-Amplitude 1-MHz Standing Ultrasonic Field on the Algae Hydrodictyon

When portions of a Hydrodictyon reticulatum colony were exposed to a high-amplitude l-MHz ultrasonic standing wave, the cells of this green algae were typically destroyed by cavitation in the sur- rounding water. If cavitation did not occur, however, another ultrasonic hioeffect could be discerned: regularly spaced markings gradually ap- peared in the cytoplasm of the cells. Peak pressure amplitudes in the field were 1-2 MPa, with exposure durations of up to 30 min. The markings appear to be the result of acoustic streaming generated in the cytoplasm when a transverse standing wave is induced in the cell walls. A theoretical prediction of the spacing, based on theory for a membrane under tension, is in rough agreement with the observed spacing of the markings. This phenomenon is a rare example of an ul- trasonic bioeffect, which is not attributable either to heating or to cav- itation.
Properties of Ion Clusters: Interactions of [Ru(NH3)5H2O]3+ and [Ru(NH3)6]3+ with [Ru(CN)6]4- and [Fe(CN)6]4-

A study of the kinetics of formation of inner-sphere complexes between [Ru(NH3)5H2O]3+ and [Ru(CN)6]4- or [Fe(CN)6]4- indicated that outer-sphere ion clusters of high order form. Measurements of the areas of intervalence bands are consistent with binding of the ions in excess at octahedral faces when anion concentration exceeds that of cation, and at apices (hydrogen bonding) in the inverse case. In the former case, the observations suggest that structural changes occur before the terminal composition is reached.
Group Sparse Additive Models

We consider the problem of sparse variable selection in nonparametric additive models, with the prior knowledge of the structure among the covariates to encourage those variables within a group to be selected jointly. Previous works either study the group sparsity in the parametric setting (e.g., group lasso), or address the problem in the non-parametric setting without exploiting the structural information (e.g., sparse additive models). In this paper, we present a new method, called group sparse additive models (GroupSpAM), which can handle group sparsity in additive models. We generalize the l1/l2 norm to Hilbert spaces as the sparsity-inducing penalty in GroupSpAM. Moreover, we derive a novel thresholding condition for identifying the functional sparsity at the group level, and propose an efficient block coordinate descent algorithm for constructing the estimate. We demonstrate by simulation that GroupSpAM substantially outperforms the competing methods in terms of support recovery and prediction accuracy in additive models, and also conduct a comparative experiment on a real breast cancer dataset.
The Nilpotent filtration and the action of automorphisms on the cohomology of finite p-groups

We study H*(P), the mod p cohomology of a finite p-group P, viewed as an module. In particular, we study the conjecture, first considered by Martino and Priddy, that, if e is a nonzero idempotent, then the Krull dimension of eH*(P) equals the rank of P. We prove this for all p-groups when p is odd, and for many 2-groups.
Agricultural Prices in the 1970's: How Will Value Be Established?

The method of value determination for agricultural commodities and products is likely to be of major concern during the balance of the 1970's. Food and agricultural prices are currently in the forefront of public interest. This concern is likely to continue and be more dramatic at times during the rest of this decade. Attention is likely to focus on the marketplace and arrangements for price determination. Several writers in the field argue that the manner in which agricultural prices are determined presents some major equity problems. They envision more problems ahead. Some conclude that there must be better mechanisms, institutions, organizational arrangements and procedures for determining the value of agriculture products. This concern implies a belief that a relationship exists between the method or process of price determination and performance. However, we know very little about the formation of prices, and we have very little empirical evidence on which to base firm conclusions about alternative arrangements.
MetaRing-a full-duplex ring with fairness and spatial reuse

The design principles of a ring network with spatial bandwidth reuse are described. A distributed fairness mechanism for this architecture, which uses low latency hardware control signals, is presented. The basic fairness mechanism can be extended for implementing multiple priority levels and integration of asynchronous with synchronous traffic. The ring is full-duplex and has two basic modes of operation: buffer insertion mode for variable-size packets and slotted mode for fixed-size packets or cells. Concurrent access and spatial reuse allow simultaneous transmissions over disjoint segments of a bidirectional ring and can increase the effective throughput by a factor of four or more. The combination of a full-duplex ring, spatial reuse, a reliable fairness mechanism, and the exploitation of advent in fiber-optic technology are the basis for the MetaRing network architecture. >
Sodium Silicate Based Thermal Interface Material for High Thermal Contact Conductance

Sodium silicate based thermal interface pastes give higher thermal contact conductance across conductor surfaces than polymer based pastes and oils, due to their higher fluidity and the consequent greater conformability. Addition of hexagonal boron nitride particles up to 16.0 vol. percent further increases the conductance of sodium silicate, due to the higher thermal conductivity of BN. However, addition beyond 16.0 vol. percent BN causes the conductance to decrease, due to the decrease in fluidity. At 16.0 vol. percent BN, the conductance is up to 63 percent higher than those given by silicone based pastes and is almost as high as that given by solder. Water is almost as effective as sodium silicate without filler, but the thermal contact conductance decreases with time due to the evaporation of water. Mineral oil and silicone without filler are much less effective than water or sodium silicate without filler. @S1043-7398~00!00402-3#
A bilingual VOYAGER system

This paper describes our initial efforts at porting the VOYAGER spoken language system to Japanese. In the process we have reorganized the structure of the system so that language dependent information is separated from the core engine as much as possible. For example, this information is encoded in tabular or rule-based form for the natural language understanding and generation components. The internal system manager, discourse and dialogue component, and database are all maintained in language transparent form. Once the generation component was ported, data were collected from 40 native speakers of Japanese using a wizard collection paradigm. A portion of these data was used to train the natural language and segment-based speech recognition components. The system obtained an overall understanding accuracy of 52% on the test data, which is similar to our earlier reported results for English [1].
Equilibrium tax rates and income redistribution: A laboratory study

This paper reports results from a laboratory experiment that investigates the Meltzer–Richard model of equilibrium tax rates, inequality, and income redistribution. The experiment varies the amount of wage inequality and the political process used to determine tax rates. We find that higher inequality leads to higher tax rates; the effect is significant and large in magnitude. The tax rates and labor supply functions are both quantitatively close to the theory. The result is robust to the political institution. The theoretical model of Meltzer–Richard is extended to incorporate social preferences in the form of altruism and inequity aversion, which are found to have negligible effects in the data.
From strings in 6d to strings in 5d

We show how recent progress in computing elliptic genera of strings in six dimensions can be used to obtain expressions for elliptic genera of strings in five-dimensional field theories which have a six-dimensional parent. We further connect our results to recent mathematical results about sheaf counting on ruled surfaces.
On greedy adaptive measurements

The purpose of this article is to examine the greedy adaptive measurement policy in the context of a linear Guassian measurement model with an optimization criterion based on information gain. In the special case of sequential scalar measurements, we provide sufficient conditions under which the greedy policy actually is optimal in the sense of maximizing the net information gain. In the general setting, we also discuss cases where the greedy policy is not optimal.
Genomic and physiological characterization of the chromate-reducing, aquifer-derived firmicute Pelosinus sp. strain HCF1

Pelosinus spp. are fermentative firmicutes that were recently reported to be prominent members of microbial communities at contaminated subsurface sites in multiple locations. Here we report metabolic characteristics and their putative genetic basis in Pelosinus sp. strain HCF1, an isolate that predominated anaerobic, Cr(VI)-reducing columns constructed with aquifer sediment. Strain HCF1 ferments lactate to propionate and acetate (the methylmalonyl-coenzyme A [CoA] pathway was identified in the genome), and its genome encodes two [NiFe]- and four [FeFe]-hydrogenases for H2 cycling. The reduction of Cr(VI) and Fe(III) may be catalyzed by a flavoprotein with 42 to 51% sequence identity to both ChrR and FerB. This bacterium has unexpected capabilities and gene content associated with reduction of nitrogen oxides, including dissimilatory reduction of nitrate to ammonium (two copies of NrfH and NrfA were identified along with NarGHI) and a nitric oxide reductase (NorCB). In this strain, either H2 or lactate can act as a sole electron donor for nitrate, Cr(VI), and Fe(III) reduction. Transcriptional studies demonstrated differential expression of hydrogenases and nitrate and nitrite reductases. Overall, the unexpected metabolic capabilities and gene content reported here broaden our perspective on what biogeochemical and ecological roles this species might play as a prominent member of microbial communities in subsurface environments.
Technology Considerations for the Use of Multiple Beam Antenna Systems in Communication Satellites

The general usage of multibeam antennas in satellite communication system is reviewed, and design constraints for a six-beam reconfigurable satellite antenna system are considered. These show that losses in the variable beam-forming network (BFN) Iimit performance achievable with a conventional common-power-amplifier/receiver system. An alternative design for an active BFN is presented, and relative performance predicted at 4/6, 11/14, and 20/30 GHz.
Minimax Policies for Selling an Asset and Dollar Averaging

The results of this paper fall into two areas. First, it is shown that the conventional wisdom of dollar averaging is related to hedging against, large regrets rather than unfavorable outcomes. Suppose that a given sum of dollars is to be irreversibly converted into stock within a given number of periods. Suppose that the share price of dollars follows an arithmetic random walk. It is shown that dollar averaging is a nonsequential minimax strategy, if the largest possible price increase in each period is equal to the largest possible decrease. On the other hand, it is shown that dollar averaging cannot be a nonsequential expected utility maximizing strategy for any strictly concave utility function and any arithmetic random walk. Second, sequential minimax strategies are examined. Here the analysis may be viewed as an extension of the literature on the optimal time to sell an asset or the optimal stopping problem. The minimax sequential strategy is shown to be of the following form. At any time there exists a critical value which depends only on n, the difference between the maximum price since conversions began and the current price. Funds held in excess of this value are converted into stock, otherwise no funds are converted. The critical values are shown to be decreasing functions of n. When the share price of dollars rises i.e., stock prices fall few funds are converted while decreases produce large conversions. These results seem to correspond to the second thoughts of those, embarking on nonsequential policies of the dollar averaging type. Buying and selling minimax policies are shown to be symmetric. Sequential minimaxing will tend to have a reinforcing effect on price movements.
An introduction to right-angled Artin groups

Recently, right-angled Artin groups have attracted much attention in geometric group theory. They have a rich structure of subgroups and nice algorithmic properties, and they give rise to cubical complexes with a variety of applications. This survey article is meant to introduce readers to these groups and to give an overview of the relevant literature.
Adaptive fuzzy sliding control for a three-link passive robotic manipulator

An adaptive fuzzy sliding control scheme is proposed to control a passive robotic manipulator. The motivation for the design of the adaptive fuzzy sliding controller is to eliminate the chattering and the requirement of pre-knowledge on bounds of error associated with the conventional sliding control. The stability and convergence of the adaptive fuzzy sliding controller is proven both theoretically and practically by simulations. A three-link passive manipulator model with two unactuated joints is derived to be used in the simulations. Simulation results demonstrate that the proposed system is robust against structured and unstructured uncertainties.
Stimulus intensity and foreperiod effects in intersensory facilitation.

Intersensory facilitation refers to the more rapid reaction time (RT) to a target in one modality and an accessory stimulus in a different modality compared to a RT to the target alone. Prior studies suggest two processes contribute to the phenomenon, termed the preparatory state and energy integration which refer to the action of accessory stimulation in providing forewarning and intensifying the reaction signal, respectively. Experiment I factorially varied foreperiod duration, light (target) intensity and tone (accessory) intensity in a discriminative RT task. The results were that foreperiod (preparatory state) and intensity (energy integration) effects were additive, implying that they affected separate processing stages. Accessory stimulus intensity affected false alarm rate on catch trials. This suggests that energy integration involves a form of response bias (increased likelihood of responding) and not facilitation (more rapid information processing). Experiment II indicated that comparable energ...
Structural Reform of Social Security

Governments around the world have enacted or are currently considering fundamental structural reforms of their Social Security pension programs. The key feature in these reforms is a shift from a pure pay-as-you-go tax-financed system, in which taxes on current workers are primarily distributed to current retirees, to a mixed system that combines pay-as-you-go benefits with investment-based personal retirement accounts. This paper discusses how such a mixed system could work in practice and how the transition to such a change could be achieved. It then analyzes the economic gains that would result from shifting to a mixed system. I turn next to the three problems that critics raise about any investment-based plan: administrative costs, risk, and income distribution. Finally, I comment on some of the ad hoc proposals for dealing with the financial problem of Social Security without shifting to an investment-based system.