cssi/SciSciGPT-SciSciNet huggingface dataset:
Large sample theory of intrinsic and extrinsic sample means on manifolds—II

This article develops nonparametric inference procedures for estimation and testing problems for means on manifolds. A central limit theorem for Frechet sample means is derived leading to an asymptotic distribution theory of intrinsic sample means on Riemannian manifolds. Central limit theorems are also obtained for extrinsic sample means w.r.t. an arbitrary embedding of a differentiable manifold in a Euclidean space. Bootstrap methods particularly suitable for these problems are presented. Applications are given to distributions on the sphere Sd (directional spaces), real projective space ℝPN−1 (axial spaces), complex projective space ℂPk−2 (planar shape spaces) w.r.t. Veronese–Whitney embeddings and a three-dimensional shape space Σ34.
Zimbabwe's guerrilla war : peasant voices

1. Peasant revolutions: theories and methods 2. Inequalities and peasant grievances 3. Strategies, goals and appeals: continuity and change 4. Guerrilla - civilian relations: the issue of popular support 5. Struggles in the struggle 6. Legacies of the war for peasants 7. Conclusion.
Better Feature Tracking through Subspace Constraints

Feature tracking in video is a crucial task in computer vision. Usually, the tracking problem is handled one feature at a time, using a single-feature tracker like the Kanade-Lucas-Tomasi algorithm, or one of its derivatives. While this approach works quite well when dealing with high-quality video and "strong" features, it often falters when faced with dark and noisy video containing low-quality features. We present a framework for jointly tracking a set of features, which enables sharing information between the different features in the scene. We show that our method can be employed to track features for both rigid and non-rigid motions (possibly of few moving bodies) even when some features are occluded. Furthermore, it can be used to significantly improve tracking results in poorly-lit scenes (where there is a mix of good and bad features). Our approach does not require direct modeling of the structure or the motion of the scene, and runs in real time on a single CPU core.
Charge equilibrium and radiation of low-energy cosmic rays passing through interstellar medium

The charge equilibrium and radiation of an oxygen and an iron beam in the MeV per nucleon energy range, representing a typical beam of low-energy cosmic rays passing through the interstellar medium, is considered. Electron loss of the beam has been taken into account by means of the First Born approximation allowing for the target atom to remain unexcited, or to be excited to all possible states. Electron capture cross sections have been calculated by means of the scaled Oppenheimer-Brinkman-Kramers approximation, taking into account all atomic shells of the target atoms. Radiation of the beam due to electron capture into the excited states of the ion, collisional excitation and collisional inner-shell ionization of the ions has been considered. Effective X-ray production cross sections and multiplicities for the most energetic X-ray lines emitted by the Fe and O beams have been calculated.
OPERATIVE TECHNIQUES AND RECURRENCE RATES ASSOCIATED WITH GASTRIC VOLVULUS IN THE DOG

Numerous surgical procedures have been attempted to correct the immediate emergency associated with the gastric dilation-volvulus syndrome in the dog. These surgical procedures included anatomical repositioning alone, gastropexy, gastrotomy with an occasional partial gastrectomy, pyloric surgery, pharyngostomy tube, and splenectomy. None of these procedures has been shown to totally prevent recurrence of gastric volvulus.
Har Gobind Khorana 1922-2011.

Gobind Khorana was a scientist who traversed boundaries, both scientifically and culturally. He pioneered the use of concepts and tools from chemistry and physics to tackle fundamental questions of biology. In particular, he helped to decipher how RNA encodes for the synthesis of protein, research that earned him the Nobel Prize in Medicine with Marshall Nirenberg and Robert Holley in 1968. Although deeply modest and unassuming, Gobind would often remark, “I only work on big problems.” Indeed, only such challenges were worthy of the extraordinary intensity, creativity, and focus that Gobind brought to a question.
REGULARIZED GREEN'S FUNCTION FOR THE INVERSE SQUARE POTENTIAL

A Green's function approach is presented for the D-dimensional inverse square potential in quantum mechanics. This approach is implemented by the introduction of hyperspherical coordinates and the use of a real-space regulator in the regularized version of the model. The application of Sturm–Liouville theory yields a closed expression for the radial energy Green's function. Finally, the equivalence with a recent path-integral treatment of the same problem is explicitly shown.
UV absorption cross sections of HO2NO2 between 343 and 273 K

The UV absorption spectrum of gas phase HO2NO2 (PNA, peroxynitric acid) was measured over the wavelength range 220 to 350 nm at temperatures between 273 and 343 K using a diode array spectrometer. Contributions to the measured spectra from HNO3, H2O2 and NO2 were subtracted by using mass spectral detection of HNO3 and H2O2 and UV/Vis absorption for NO2. Our HO2NO2 absorption spectra have been scaled to the previously reported absorption cross section data of Molina and Molina [L. T. Molina and M. J. Molina, J. Photochem., 1981, 15, 97] and Singer et al. [R. J. Singer, J. N. Crowley, J. P. Burrows, W. Schneider and G. K. Moortgat, J. Photochem. Photobiol., A: Chemistry, 1989, 48, 17] at 250 nm. Our measured HO2NO2 cross sections at wavelengths longer than 290 nm are compared with literature values and the discrepancies are discussed. An empirical parametrization of the measured HO2NO2 cross section temperature dependence for use in atmospheric model calculations is presented.
Key Issues in Developing School-Linked, Integrated Services

This article identifies several nuts-and-bolts issues involved in planning and implementing school-linked services. Effective planning must include discussion of implementation details and is possible only if a policy-minded team of coequals works toward the same goals. No one agency should "own" the process. In addition to education, health, and social services agency leaders, the team should include representatives of community and neighborhood groups, line workers, and parents. This team must carefully address questions of targeting, governance, financing, evaluation, and information sharing. In addition, team members must consider operational issues such as ensuring line worker buy-in and establishing an effective case management staffing plan that is acceptable to existing staff. The article discusses different strategies that community teams can use to address each of these issues. he development of school-linked services has progressed to a point where we can begin to distill the most effective approaches to planning and implementing these programs. In this journal issue the article by Levy and Shepardson discusses key elements of these programs. This article identifies some of the nuts-and-bolts issues that must be addressed when establishing school-linked service programs. These include planning, targeting, governance, information systems, and staffing.
IMAGING THE MOLECULAR DISK ORBITING THE TWIN YOUNG SUNS OF V4046 Sgr

We have imaged the disk surrounding the nearby (D {approx} 73 pc), {approx}12 Myr, classical T Tauri binary system V4046 Sgr with the Submillimeter Array (SMA) at an angular resolution of {approx}2''. We detect a rotating disk in {sup 12}CO(2-1) and {sup 13}CO(2-1) emission and resolve the continuum emission at 1.3 mm. We infer disk gas and dust masses of {approx}110 and {approx}40 Earth masses, respectively. Fits to a power-law disk model indicate that the molecular disk extends to {approx}370 AU and is viewed at an inclination of between {approx}33{sup 0} and {approx}39{sup 0} for dynamical stellar masses ranging from 1.8 M {sub sun} down to 1.5 M {sub sun} (the range of the total mass previously determined for the central, 2.4 day spectroscopic binary). This range of disk inclination is consistent with that assumed in deducing the central binary mass (i.e., 35{sup 0}), suggesting that the V4046 Sgr binary system and its circumbinary, molecular disk are coplanar. In light of the system's age and binarity, the presence of an extensive molecular disk orbiting V4046 Sgr provides constraints on the timescales of processes related to Jovian planet formation and demonstrates that circumbinary Jovian planets potentially could form around close binarymore » systems.« less
Application of Optimization Technology to Wing/Store Flutter Prediction

Gradient-directed numerical search techniques, using derivatives of flutter speed with respect to store parameters, are applied to the problem of determining critical flutter configurations for a wing with multiple external stores. The elementary steepest-descent method is first applied to demonstrate the feasibility of the overall approach; a more efficient and reliable algorithm (rank-one-correction) is later introduced to obtain a satisfactory search procedure. Applications to a twoand a four-variable problem are presented. The method offers a useful alternative to current practices and can reduce the potentially catastrophic possibility of "missing" critical store configurations.
Is it signalling? Exchange intervention and the dollar-Deutschemark rate

Abstract The portfolio balance channel for sterilised intervention is tested by examining the effects of changes in relative asset supplies on the dollar-Deutschemark rate during the 1980s. In contrast to previous studies, we control for any signalling effects of central bank intervention and find a weak, but statistically significant, portfolio balance influence on the exchange rate.
Simulated changes in extreme temperature and precipitation events at 6 ka

Abstract We have employed a high-resolution regional climate model (RCM) to test the sensitivity of extreme climate events to 6 ka orbital forcing, using western North America as a case study. Calculated differences ( 6 ka − Control ) in annual extreme precipitation event frequency were mostly positive throughout the RCM domain, as were differences in extreme event contribution to total annual precipitation. These annual mean differences were driven by changes in the seasonal distribution of extreme precipitation events at 6 ka, which was in turn linked to changes in the daily variability of upper-level zonal wind speeds over the northeast Pacific. Positive differences in the frequency of extreme maximum daily temperature values occurred inland in the RCM domain, with peak differences of 28 days/year over the Great Basin. Likewise, days in which the maximum daily temperature exceeded 32 °C were 24% more frequent in the 6 ka integration than in the control integration and heat waves lasted up to 12 days longer. Mean first and last freeze dates were generally earlier in the 6 ka integration along the Pacific coast and over the southern Great Basin, and later over the northern Great Basin and interior of the Pacific Northwest. We propose that, by exerting controls on paleoclimate archives unique from changes in the mean climate state, such changes in the frequency and duration of extreme climate events could have played a substantial role in shaping the mid-Holocene paleoclimate record of the region, and that extreme climate events may have been similarly important in other regions and during other time periods.
Geometry of the Cramer-Rao bound

Abstract The Fisher information matrix determines how much information a measurement brings about the parameters that index the underlying probability distribution for the measurement. In this paper we assume that the parameters structure the mean value vector in a multivariate normal distribution. The Fisher matrix is then a Gramian constructed from the sensitivity vectors that characterize the first-order variation in the mean with respect to the parameters. The inverse of the Fisher matrix lower bounds the covariance of any unbiased estimator of the parameters. This inverse has several geometrical properties that bring insight into the problem of identifying multiple parameters. For example, it is the angle between a given sensitivity vector and the linear subspace spanned by all other sensitivity vectors that determines the variance bound for identifying a given parameter. Similarly, the covariance for identifying the linear influence of two different subsets of parameters depends on the principal angles between the linear subspaces spanned by the sensitivity vectors for the respective subsets. These geometrical interpretations may also be given filtering interpretations in a related multivariate normal estimation problem.
Women, Wealth and Mobility

Using estate tax returns data, we observe that the share of women among the very wealthy in the United States peaked in the late 1960s at nearly one-half and then declined to one-third. We argue that this pattern reflects changes in the importance of dynastic wealth, with the share of women proxying for inher? ited wealth. If so, wealth mobility decreased until the 1970s and rose thereafter. Such an interpretation is consistent with technological change driving long term trends in mobility and inequality, as well as the recent divergence between top wealth and top income shares documented elsewhere. (JEL D31, J16, J62, 033) The extent of, and changes in, intergenerational mobility of wealth are central to understanding dynamics of wealth inequality, but are hard to measure. In this paper we argue that the share of women among the wealthiest Americans can be used as a proxy for the importance of inherited rela? tive to self-made wealth. This approach assumes that women tend to inherit rather than make great fortunes. If so, a higher share of women among the wealthy would reflect a rise in inherited wealth at the top, and, thus, lower wealth mobility. Conversely, higher wealth mobility where self-made wealth replaces inherited wealth would result in more men at the top of the wealth distribution. Judged by this proxy, and corroborated by various data sources, wealth mobility decreased in the period 1925? 1969 and increased thereafter. Such a pattern is consistent with an important role for technological change in shaping the wealth distribution, and can provide an explanation for why wealth concentra? tion has remained stable, despite increasing income concentration in the last three decades. Over the past century, the share of women among the very wealthy followed an inverse-U pattern, peaking in the late 1960s. According to estate tax returns, in 1925 one-quarter of the wealthiest 0.01 percent were women. This fraction rose rapidly through World War II (WWII) and then more slowly to peak in 1969, when women neared parity with men. Since then, the decline has been marked. By 2000, women's share had fallen to one-third, its prewar level. While the rise was evident among all wealth groups in the top 1 percent of the wealth distribution, the decline was confined to the very top. Figure IA graphs the share of women for four different groups in the top 1 percent among decedents by year. Figure IB does the same for the "living" population with the help of estate-multipliers (a method that treats death as a random sampling device and uses mortality rates by age and gender to infer the distribution of wealth among the living, as described in the Data Appendix). While the rise in the share of women among the wealthy until the 1960s could reflect improve? ments in women's economic status, labor market gains work against the recent decline. For instance, since the 1970s, the share of women among top earners (top 0.1 percent) has risen by
QUANTIFYING THE UNCERTAINTY IN THE ORBITS OF EXTRASOLAR PLANETS

Precise radial velocity measurements have led to the discovery of ~100 extrasolar planetary systems. We investigate the uncertainty in the orbital solutions that have been fitted to these observations. Understanding these uncertainties will become more and more important as the discovery space for extrasolar planets shifts to longer and longer periods. While detections of short-period planets can be rapidly refined, planets with long orbital periods will require observations spanning decades to constrain the orbital parameters precisely. Already in some cases, multiple distinct orbital solutions provide similarly good fits, particularly in multiple-planet systems. We present a method for quantifying the uncertainties in orbital fits and addressing specific questions directly from the observational data rather than relying on best-fit orbital solutions. This Markov chain Monte Carlo (MCMC) technique has the advantage that it is well suited to the high-dimensional parameter spaces necessary for the multiple-planet systems. We apply the MCMC technique to several extrasolar planetary systems, assessing the uncertainties in orbital elements for several systems. Our MCMC simulations demonstrate that for some systems there are strong correlations between orbital parameters and/or significant non-Gaussianities in parameter distributions, even though the measurement errors are nearly Gaussian. Once these effects are considered, the actual uncertainties in orbital elements can be significantly larger or smaller than the published uncertainties. We also present simple applications of our methods, such as predicting the times of possible transits for GJ 876.
THE IMPACT OF ICM SUBSTRUCTURE ON RAM PRESSURE STRIPPING

Cluster galaxies moving through the intracluster medium (ICM) are expected to lose some of their interstellar medium (ISM) through ram pressure stripping and related ISM-ICM interactions. Using high-resolution cosmological simulations of a large galaxy cluster including star formation, we show that the ram pressure a galaxy experiences at a fixed distance from the cluster center can vary by well over an order of magnitude We find that this variation in ram pressure is due in almost equal parts to variation in the ICM density and in the relative velocity between the galaxy and the ICM. We also find that the ICM and galaxy velocities are weakly correlated for infalling galaxies.
Hierarchical channel router

Abstract The channel routing problem is a special case of the wire routing problem when interconnections have to be performed within a rectangular strip having no obstructions between terminals located on opposite sides of the rectangle. We present here a new channel routing algorithm, based on reduction of the problem to the case of a ( 2 × n ) grid and on consistent utilization of a ‘divide-and-conquer’ approach. For the current implementation of the algorithm, the running time is proportional to N ∗ n log (m) where N is the number of nets, n the length of the channel (number of columns) and m the width of the channel (number of tracks). Traditional technological restrictions are assumed, ie, net terminals are located on vertical grid lines, two wiring layers are available for interconnections. One layer is used exclusively for vertical segments and another for horizontal. Vias are introduced for each layer change. This algorithm consistently outperforms several known routers in quality of wiring. We tested the algorithm on several benchmark problems. One of them, Deutsch's ‘difficult example’, was routed with only 19 horizontal wiring tracks (the absolute minimum for this case), whereas all other known routers required 20 or more tracks.
RNA Bind-n-Seq: Quantitative Assessment of the Sequence and Structural Binding Specificity of RNA Binding Proteins

Specific protein-RNA interactions guide posttranscriptional gene regulation. Here, we describe RNA Bind-n-Seq (RBNS), a method that comprehensively characterizes sequence and structural specificity of RNA binding proteins (RBPs), and its application to the developmental alternative splicing factors RBFOX2, CELF1/CUGBP1, and MBNL1. For each factor, we recovered both canonical motifs and additional near-optimal binding motifs. RNA secondary structure inhibits binding of RBFOX2 and CELF1, while MBNL1 favors unpaired Us but tolerates C/G pairing in motifs containing UGC and/or GCU. Dissociation constants calculated from RBNS data using a novel algorithm correlated highly with values measured by surface plasmon resonance. Motifs identified by RBNS were conserved, were bound and active in vivo, and distinguished the subset of motifs enriched by CLIP-Seq that had regulatory activity. Together, our data demonstrate that RBNS complements crosslinking-based methods and show that in vivo binding and activity of these splicing factors is driven largely by intrinsic RNA affinity.
Limits of incompressible surfaces

Abstract One can embed arbitrarily many disjoint, non-parallel, non-boundary parallel, incompressible surfaces in any three manifold with at least one boundary component of genus two or greater (Howards, 1998). This paper proves the contrasting, but not contradictory result that although one can sometimes embed arbitrarily many surfaces in a 3-manifold it is impossible to ever embed an infinite number of such surfaces in any compact, orientable 3-manifold M .
Synthesis and Optical Properties of Photochromic Perinaphthothioindigo

Abstract (1,2-naphtho)(1,8-naphtho)thioindigo (PNT) has been synthesized following a simple Friedel–Crafts route and its photochemical properties in toluene and polymethylmethacrylate (PMMA) have been characterized. PNT is a photochromic molecule capable of reversible photoisomerization between a yellow form ( cis -PNT, λ max = 484 nm) and a purple form ( trans -PNT, λ max = 595 nm). The stable purple form converts to the yellow form with a trans -PNT to cis -PNT conversion quantum yield of 0.027 in toluene and 0.062 in PMMA. The unstable yellow form exhibits a cis -PNT to trans -PNT quantum efficiency of conversion of 0.27–0.85 in toluene and 0.17–0.68 PMMA, with highest conversion efficiency occurring in the vicinity of its λ max of 484 nm. trans -PNT has a strong fluorescence quantum yield, 0.14 (toluene) and 0.16 (PMMA). For samples prepared photochemically in the cis -PNT form, slow thermal relaxation to the trans form occurs in the dark, with a half life of about 17 h in toluene (25 °C) and even slower, 168 h, in PMMA. The property of photoswitching between fluorescent and non-fluorescent forms makes this material a candidate for many applications in imaging and data storage.
Development Of The Compound Parabolic Collector For Photo-Thermal And Photo-Voltaic Applications

We describe principles of design and experimental tests of the compound parabolic collector (CPC) concept for concentrating solar energy onto a receiver. Because of its wide angle of acceptance, the CPC can concentrate solar energy up to a factor ten without diurnal tracking of the sun, making it well suited for use in applications as a source of relatively high temperature (150 - 400°F) heat or an optical concentrator to reduce surface area requirements of photovoltaic cells.© (1976) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Optimal Design of Centered Squeeze Film Dampers

A two degree-of-freedom model, consisting of a rigid rotor supported on rigid bearings which are in turn supported on squeeze film dampers, is considered. Isotropic centering springs are assumed resulting in a steady synchronous centered circular response for the rotor. The resulting nonlinear system is modeled in nondimensional form. The transmissibility ratio of the system as well as the power dissipated are minimized for various values of unbalance and at several speeds, with the squeeze film bearing parameter as the primary design variable. Expressions are derived for linear variational stability of the circular orbit, and are imposed as constraints in the optimization process. The dependence of the optimal configuration on speed and unbalance is discussed.
The importance of the solar tachocline

Abstract The solar tachocline, a thin layer containing the strong radial differential rotation at the base of the convection zone has proven to be important for several reasons. Radial shear there is likely to generate the Sun’s strongest toroidal fields, which eventually erupt as bipolar spots at the surface, and the tachocline provides a good location for magnetic flux-storage. The subadiabatic stratification of this layer allows storage of strong toroidal field despite its magnetic buoyancy, while toroidal bands are held against poleward slip by either the prolateness of this layer, or by jet-like flows within the band, or both. Global HD and MHD instabilities that are theoretically predicted to occur in this layer produce two major results. One is the production of large-scale non-axisymmetries, by tipping or deforming the toroidal band, and the other is the generation of kinetic helicity. Both have important implications in solar dynamos. The former could be responsible for producing the Sun’s “active-longitudes”, while the latter produces the extended dipolar poloidal fields that are necessary for magnetically coupling the Sun’s N- and S-hemispheres. We will review these theoretical results, and indicate features to look for in the helioseismic data, such as, prolateness, amplitude and location of jets in the tachocline, including their variations with the solar cycle; as well as helical flows and their spatial and temporal dependence.
Solar Flare X-Ray Spectra from the P78 - 1 Spacecraft

Results from the high resolution solar X-ray spectrometer experiments on the P78-1 spacecraft are discussed. These results concern physical quantities such as electron temperature and density, turbulence, mass motions, and state of ionization equilibrium, characteristic of the thermal soft X-ray emitting flare plasma, and the time behavior of these quantities during flares. In addition, a brief description of the instruments is given, the plasma diagnostics used in interpreting the spectra are summarized, and the origin of the thermal soft X-ray emitting plasma is discussed in light of the P78-1 results, earlier data, and numerical simulations of magnetic flux tubes heated to solar flare temperatures.
Zonal Momentum Balance in the Tropical Atmospheric Circulation during the Global Monsoon Mature Months

AbstractIn this paper, zonal momentum balances of the tropical atmospheric circulation during the global monsoon mature months (January and July) are analyzed in three dimensions based on the ECMWF Interim Re-Analysis (ERA-Interim). It is found that the dominant terms in the balance of the atmospheric boundary layer (ABL) in both months are the pressure gradient force, the Coriolis force, and friction. The nonlinear advection term plays a significant role only in the Asian summer monsoon regions within the ABL. In the upper troposphere, the pressure gradient force, the Coriolis force, and the nonlinear advection are the dominant terms. The transient eddy force and the residual force (which can be explained as convective momentum transfer over open oceans) are secondary, yet cannot be neglected near the equator. Zonal-mean equatorial upper-troposphere easterlies are maintained by the absolute angular momentum advection associated with the cross-equatorial Hadley circulation. Equatorial upper-troposphere ea...
Modelling collision products of triple-star mergers

In dense stellar clusters, binary-single and binary-binary encounters can ultimately lead to collisions involving two or more stars during a resonant interaction. A comprehensive survey of multistar collisions would needto explore an enormous amount of parameter space, but here we focus on a number of representative cases involving low-mass (0.4-, 0.6- and 0.8-M O .) main-sequence stars. Using both smoothed particle hydrodynamics (SPH) calculations and a much faster fluid sorting software package (MMAS), we study scenarios in which a newly formed product from an initial collision collides with a third parent star. By varying the order in which the parent stars collide, as well as the orbital parameters of the collision trajectories, we investigate how factors such as shock heating affect the chemical composition and structure profiles of the collision product. Our simulations and models indicate that the distribution of most chemical elements within the final product is not significantly affected by the order in which the stars collide, the direction of approach of the third parent star, or the periastron separations of the collisions. Although the exact surface abundances of beryllium and lithium in the product do depend on the details of the dynamics, these elements are always severely depleted due to mass loss during the collisions. We find that the sizes of the products, and hence their collisional cross-sections for subsequent encounters, can be sensitive to the order and geometry of the collisions. For the cases that we consider, the radius of the product formed in the first (single-single star) collision ranges anywhere from roughly 2-30 times the sum of the radii of its parent stars. The size of the final product formed in our triple-star collisions is more difficult to determine, but it can easily be as large or larger than a typical red giant. Although the vast majority of the volume in such a product contains diffuse gas that could be readily stripped in subsequent interactions, we nevertheless expect the collisional cross-section of a newly formed product to be greatly enhanced over that of a thermally relaxed star of the same mass. Our results also help establish that the algorithms of MMAS can quickly reproduce the important features of our SPH models for these collisions, even when one of the parent stars is itself a former product.
Improving the Performance of the Education Sector: The Valuable, Challenging, and Limited Role of Random Assignment Evaluations

In an attempt to improve the quality of educational research, the US Department of Education's Institute of Education Sciences has provided funding for 65 randomized controlled trials of educational interventions. We argue that this research methodology is more effective in providing guidance to extremely troubled schools about how to make some progress than guidance to schools trying to move from making some progress to becoming high-performance organizations. We also argue that the conventional view of medical research—discoveries made in specialized laboratories that are then tested using randomized control trials—is an inaccurate description of the sources of advances in medical practice. Moreover, this conventional view of the sources of advances in medical practice leads to incorrect inferences about how to improve educational research. We illustrate this argument using evidence from the history of medical research on the treatment of cystic fibrosis.
Modeling Coupled Evaporation and Seepage in Ventilated Cavities

Cavities excavated in unsaturated geological formations are important to activities such as nuclear waste disposal and mining. Such cavities provide a unique setting for simultaneous occurrence of seepage and evaporation. Previously, inverse numerical modeling of field liquid-release tests and associated seepage into cavities were used to provide seepage-related large-scale formation properties, ignoring the impact of evaporation. The applicability of such models was limited to the narrow range of ventilation conditions under which the models were calibrated. The objective of this study was to alleviate this limitation by incorporating evaporation into the seepage models. We modeled evaporation as an isothermal vapor diffusion process. The semiphysical model accounts for the relative humidity (RH), temperature, and ventilation conditions of the cavities. The evaporation boundary layer thickness (BLT) over which diffusion occurs was estimated by calibration against free-water evaporation data collected inside the experimental cavities. The estimated values of BLT were 5 to 7 mm for the open underground drifts and 20 mm for niches closed off by bulkheads. Compared with previous models that neglected the effect of evaporation, this new approach showed significant improvement in capturing seepage fluctuations into open cavities of low RH. At high relative-humidity values (>85%), the effect of evaporation on seepage was very small.
The Palomar Abell Cluster Optical Survey. I. Photometric Redshifts for 431 Abell Clusters

This paper presents photometric redshifts for 431 Abell clusters imaged as part of the Palomar Abell Cluster Optical Survey, of which 236 are new redshifts. We have obtained moderately deep, three-band (Gunn gri) imaging for this sample at the Palomar Observatory 60 inch (1.5 m) telescope, as part of the photometric calibration of the Digitized Second Palomar Sky Survey. Our data acquisition, reduction, and photometric calibration techniques are described, and photometric accuracy and consistency are demonstrated. An empirical redshift estimator is presented, utilizing background-corrected median g-r colors and mean g magnitudes for the ensemble of galaxies in each field. We present photometric redshift estimates for the clusters in our sample with an accuracy of σz = 0.038. These redshift estimates provide checks on single-galaxy cluster redshifts, as well as distance information for studies of the Butcher-Oemler effect, luminosity functions, mass-to-light ratios, and many other projects.
Uncovering the charming Higgs at the LHC

We study the observability of the Higgs boson in the “charming Higgs” model. In this model the Higgs boson primarily undergoes a cascade decay to four charm quarks via light intermediate pseudoscalars. Such a decay allows the Higgs boson to escape the most stringent LEP bounds on the Standard Model Higgs boson mass. If the light pseudoscalars are sufficiently light they become highly boosted and their decay products collimated into jets. We show that by using jet substructure techniques, this model is potentially observable at the LHC. For a Higgs boson mass of 100 GeV and light pseudoscalar mass of 12 GeV, we find a signal significance of 3.8σ with a luminosity of 30 fb−1 and that a 5σ significance can be obtained with 50 fb−1 of luminosity at the 14 TeV LHC.
Long-Term Evolution of Massive Black Hole Binaries

The long-term evolution of massive black hole binaries at the centers of galaxies is studied in a variety of physical regimes, with the aim of resolving the final parsec problem, i.e., how black hole binaries manage to shrink to separations at which emission of gravity waves becomes efficient. A binary ejects stars by the gravitational slingshot and carves out a loss cone in the host galaxy. Continued decay of the binary requires a refilling of the loss cone. We show that the standard treatment of loss cone refilling, derived for collisionally relaxed systems like globular clusters, can substantially underestimate the refilling rates in galactic nuclei. We derive expressions for nonequilibrium loss cone dynamics and calculate timescales for the decay of massive black hole binaries following galaxy mergers, obtaining significantly higher decay rates than heretofore. Even in the absence of two-body relaxation, decay of binaries can persist as a result of repeated ejection of stars returning to the nucleus on eccentric orbits. We show that this recycling of stars leads to a gradual, approximately logarithmic dependence of the binary binding energy on time. We derive an expression for the loss cone refilling induced by the Brownian motion of a black hole binary. We also show that numerical N-body experiments are not well suited to probe these mechanisms over long times as a result of spurious relaxation.
Summary of AIEE-IRE-ACM conference

To attempt to summarize the disclosures of this important three-day conference on information-processing systems is for me a most difficult assignment. Each paper was in itself a summary of extensive investigations, usually covering the co-operative efforts of large teams of engineers and scientists. Furthermore, I was unable personally to hear more than a few of the papers although I was fortunate in having advance copies of most of the others. For the remaining coverage I am indebted for effective reports to the good efforts of Miss Mary Stevens and Sam Alexander of the NBS staff. I am further indebted to these two for the opportunity of discussing highlights of many of the conference papers.
Quantal fluctuation limitations on reaction time to sinusoidal gratings

A model of sinusoidal grating detection based on the output of many parallel-processing spatial frequency-bandpass receptive fields is developed. The receptive fields are assumed to be of similar shape but to differ in scale and retinal location. Because the retinal image is inherently noisy due to photon noise a signal detection analysis is carried out. For a stimulus grating having a particular spatial frequency there is a most sensitive mechanism: one with a receptive field of ideal size and retinal location with respect to the stimulus. We hypothesize that subjects make reliable judgements concerning the physical presence of a grating based on the time-integrated output of the most sensitive mechanism. This leads to the prediction that reaction time to grating onset will be linearly related to the square of the grating frequency. This prediction is confirmed by data from Breitmeyer [1975, Experiment 1 (Vision Res. 15, 1411-1412)].
X-Ray Emission-Line Imaging and Spectroscopy of Tycho's Supernova Remnant

We present X-ray images of Tycho's supernova remnant in emission-line features of Mg, Si, S, Ar, Ca, and Fe, plus the continuum, using data obtained by the imaging spectrometers on board the Advanced Satellite for Cosmology and Astrophysics (ASCA). All the images show the shell-like morphology characteristic of previously obtained broadband X-ray images, but they are clearly distinct from each other. We use image reconstruction techniques to achieve a spatial resolution of ~08. Line intensity ratios are used to make inferences about the remnant's physical state, on average for the entire remnant and with angular position around the rim. The average temperature of the Si and S ejecta in the remnant is (0.8-1.1) × 107 K, and the average ionization age is (0.8-1.3) × 1011 cm-3 s. For a constant ionization age, the observed relative brightness variations of Si and S line image profiles with azimuthal angle imply differences of roughly a factor of 1.3-1.8 in the temperature. We compare the radial brightness profiles of our images with simple geometrical models and find that a spherical emitting geometry is favored over a torus. A spherical geometry is further supported by the absence of systematic Doppler shifts across the remnant. The radial fit results also suggest that some radial mixing of the ejecta has occurred. However, the azimuthally averaged Fe K image peaks at a markedly lower radius than the other images. The average Fe K/Fe L line intensity ratio and the position of the Fe K energy centroid support a temperature several times higher and an ionization age approximately a factor of 10 lower than for the other elements, and imply that the Fe ejecta must have retained some of its stratification. Although many of the features in the 4-6 keV X-ray continuum correspond to those in the radio, there is no obvious correlation between the relative brightness in these bands.
On the Nature of Traveling Ionospheric Disturbances Launched by Low‐Altitude Nuclear Explosions

The nuclear explosion of October 30, 1961, over Novaya Zemlya, resulted in major perturbations of the F-layer critical frequency, even at very great ranges from the explosion site. These perturbations have been interpreted in terms of long-period gravity waves, and more recently in terms of shorter-period acoustic-gravity waves. It is shown here that the new interpretation is unsatisfactory, while the old is perfectly consistent with the observations if allowance is made for the obliquity of energy propagation. The results have some bearing on natural traveling ionospheric disturbances as well.
Asymmetric aldol additions: use of titanium tetrachloride and (-)-sparteine for the soft enolization of N-acyl oxazolidinones, oxazolidinethiones, and thiazolidinethiones.

Asymmetric aldol additions using chlorotitanium enolates of N-acyloxazolidinone, oxazolidinethione, and thiazolidinethione propionates proceed with high diastereoselectivity for the Evans or non-Evans syn product depending on the nature and amount of the base used. With 1 equiv of titanium tetrachloride and 2 equiv of (−)-sparteine as the base or 1 equiv of (−)-sparteine and 1 equiv of N-methyl-2-pyrrolidinone, selectivities of 97:3 to >99:1 were obtained for the Evans syn aldol products using N-propionyl oxazolidinones, oxazolidinethiones, and thiazolidinethiones. The non-Evans syn aldol adducts are available with the oxazolidinethione and thiazolidinethiones by altering the Lewis acid/amine base ratios. The change in facial selectivity in the aldol additions is proposed to be a result of switching of mechanistic pathways between chelated and nonchelated transition states. The auxiliaries can be reductively removed or cleaved by nucleophilic acyl substitution. Iterative aldol sequences with high diastere...
Õ(Congestion + Dilation) Hot-Potato Routing on Leveled Networks

We study packet routing problems, in which we are given a set of N packets which will be sent on preselected paths with congestion C and dilation D. For store-and-forward routing, in which nodes have buffers for packets in transit, there are routing algorithms with a performance that matches the lower bound Ω(C+D). Motivated from optical networks, we study hot-potato routing in which the nodes are bufferless. Due to the lack of buffers, in hot-potato routing the packets may be delayed more than in store-and-forward routing. An interesting question is how much is the performance of routing algorithms affected by the absence of buffers.Here, we answer this question for the class of leveled networks, in which the nodes are partitioned into L+1 distinct levels. We present a randomized hot-potato routing algorithm for leveled networks, which routes the packets in O((C + L) ln9 (LN)) time with high probability. For routing problems with dilation Ω(L), and where N is a polynonial in L, this bound is within polylogarithmic factors of the lower bound Ω(C+L). Our algorithm demonstrates that for such routing problems the benefit from using buffers is no more than polylogarithmic; thus, hot-potato routing is an efficient way to route packets in leveled networks.In hot-potato routing, due to the lack of buffers, the packets may not be able to remain on their preselected paths during the course of routing (while in store-and-forward routing the packets remain on their preselected paths). However, in our algorithm the actual path that each packet follows contains its original preselected path; thus the lower bound Ω(C+L) is also a lower bound for the new paths. Our algorithm is distributed, that is, routing decisions are taken locally at each node while packets are routed in the network. To our knowledge, this is the first hot-potato algorithm designed and analyzed, in terms of congestion and dilation, for leveled networks.
Heckle and Chide: Results of a randomized road safety intervention in Kenya

In economies with weak enforcement of traffic regulations, drivers who adopt excessively risky behavior impose externalities on other vehicles, and on their own passengers. In light of the difficulties of correcting inter -vehicle externalities associated with weak third-party enforcement, this paper evaluates an intervention that aims instead to correct the intra-vehicle externality between a driver and his passengers, who face a collective action problem when deciding whether to exert social pressure on the driver if their safety is compromised. We report the results of a field experiment aimed at solving this collective action problem, which empowers passengers to take action. Evocative messages encouraging passengers to speak up were placed inside a random sample of over 1,000 long-distance Kenyan minibuses, or matatus, serving both as a focal point for, and to reduce the cost of, passenger action. Independent insurance claims data were collected for the treatment group and a control group before and after the intervention. Our results indicate that insurance claims fell by a half to two-thirds, from an annual rate of about 10 percent without the intervention, and that claims involving injury or death fell by at least 50%. Results of a driver survey eight months into the intervention suggest passenger heckling was a contributing factor to the improvement in safety. Available: http://www.cgdev.org/files/1421541_file_Habyarimana_Jack_Heckle_FINAL.pdf
Hopf-Bifurcation Analysis of Airfoil Flutter at Transonic Speeds

Hopf-bifurcation analysis is used to determine flutter onset for a pitch-and-plunge airfoil at transonic Mach number conditions. The pitch-and-plunge model is a coupling of the Euler equations and a twodegree-of-freedom structural model composed of linear and torsional springs. The Euler equations are discretized using the upwind total variation diminishing scheme of Harten and Yee. Equilibrium solutions of the aeroelastic model are computed using Newton's method, and dynamic solutions are explicitly integrated in time with first-order accuracy. The Hopf-bifurcation point, which models the flutter condition, is computed directly using a modified form of the Griewank and Reddien algorithm. A path of Hopf points is computed as a function of Mach number to produce a Mach flutter boundary. The flutter boundary is validated by time integration. Flutter boundaries are also obtained through variation of static pretwist and pitch and plunge damping. The direct, Hopf-point method is found to be precise and efficient for grids typical of inviscid, transonic airfoil calculations.
Development of a short-form Learning Organization Survey: the LOS-27.

Despite urgent need for innovation, adaptation, and change in health care, few tools enable researchers or practitioners to assess the extent to which health care facilities perform as learning org...
ADHA: automatic data layout framework for heterogeneous architectures

Data layouts play a crucial role in determining the performance of a given application running on a given architecture. Existing parallel programming frameworks for both multicore and heterogeneous systems leave the onus of selecting a data layout to the programmer. Therefore, shifting the burden of data layout selection to optimizing compilers can greatly enhance programmer productivity and application performance. In this work, we introduce ADHA: a two-level hierarchal formulation of the data layout problem for modern heterogeneous architectures. We have created a reference implementation of ADHA in the Heterogeneous Habanero-C (H2C) parallel programming system. ADHA shows significant performance benefits of up to 6.92× compared to manually specified layouts for two benchmark programs running on a CPU+GPU heterogeneous platform.