cssi/SciSciGPT-SciSciNet huggingface dataset:
A Critical Evaluation of Turbulence Modeling in a Model Combustor

Based on the previous benchmark studies on combustion, scalar transfer and radiation models, a critical evaluation of turbulence models in a propane-air diffusion flame combustor with interior and exterior conjugate heat transfers has been performed. Results obtained from six turbulence models are presented and compared in detail with a comprehensive database obtained from a series of experimental measurements. It is found that the Reynolds stress model (RSM), a second moment closure, is superior over the five popular eddy-viscosity two-equation models. Although the main flow patterns are captured by all six turbulence models, only the RSM is able to successfully predict the lengths of both recirculation zones and give fairly accurate predictions for mean velocity, temperature, CO2 and CO mole fractions, as well as turbulence kinetic energy in the combustor chamber. In addition, the realizable k-e (Rk-e) model illustrates better performance than four other two-equation models and can provide comparable results to those from the RSM for the configuration and operating conditions considered in the present study.Copyright © 2012 by Her Majesty the Queen in Right of Canada
Prospects for Black Farmers in the Years Ahead

BLACK RURAL population is about threetenths of the total black population. Most blacks and other minority groups, except the American Indians, live in urban areas. Between 1960 and 1968, about 28 percent of the drop in farm population was the result of the exodus of blacks and other minority groups [3, p. 58]. Many of the problems that beset blacks everywhere occur in their most severe, undiluted, and least hopeful settings in the countryside; and to the extent that rural areas continue to be a seedbed for the cities, the problems of the rural minority continue to be the problems of all [1, p. 161]. In 1964 there were 199,952 nonwhite farm operators in the United States [4, p. 760]. Of this total 92 percent were blacks and 8 percent were classified as other nonwhite. Ninety-two percent of all nonwhite operators were in the South, and of these 98 percent were black. For this analysis black is used synonymously with Negro and nonwhite. The census data for nonwhites are treated as all black, since 92 percent and 98 percent for the United States and the South, respectively, are black. Even with this overstatement of the data for blacks, the conclusions should be valid.
A convenient synthesis of phosphonothioic acids

Abstract A method for the convenient synthesis of phosphonothioates, or phosphonothioic acids, is reported. A significant advantage of the method is the alleviation of the need for purification of intermediates, other than washing with water. No chromatography is needed and the only purification step is the crystallization of the final product. The method uses standard reagents and should be applicable to the synthesis of phosphonothioic acids bearing a range of functional groups.
Derivative free gradient projection algorithms for rotation

A simple modification substantially simplifies the use of the gradient projection (GP) rotation algorithms of Jennrich (2001, 2002). These algorithms require subroutines to compute the value and gradient of any specific rotation criterion of interest. The gradient can be difficult to derive and program. It is shown that using numerical gradients gives almost precisely the same results as using exact gradients. The resulting algorithm is very easy to use because the only problem specific code required is that needed to define the rotation criterion. The computing time is increased when using numerical gradients, but it is still very modest for most purposes. While used extensively elsewhere, numerical derivatives seem to be underutilized in statistics.
Combining Fuzzy Information from Multiple Systems

In a traditional database system, the result of a query is a set of values (those values that satisfy the query). In other data servers, such as a system with queries based on image content, or many text retrieval systems, the result of a query is a sorted list. For example, in the case of a system with queries based on image content, the query might ask for objects that are a particular shade of red, and the result of the query would be a sorted list of objects in the database, sorted by how well the color of the object matches that given in the query. A multimedia system must somehow synthesize both types of queries (those whose result is a set and those whose result is a sorted list) in a consistent manner. In this paper we discuss the solution adopted by Garlic, a multimedia information system being developed at the IBM Almaden Research Center. This solution is based on “graded” (or “fuzzy”) sets. Issues of efficient query evaluation in a multimedia system are very different from those in a traditional database system. This is because the multimedia system receives answers to subqueries from various subsystems, which can be accessed only in limited ways. For the important class of queries that are conjunctions of atomic queries (where each atomic query might be evaluated by a different subsystem), the naive algorithm must retrieve a number of elements that is linear in the database size. In contrast, in this paper an algorithm is given, which has been implemented in Garlic, such that if the conjuncts are independent, then with arbitrarily high probability, the total number of elements retrieved in evaluating the query is sublinear in the database size (in the case of two conjuncts, it is of the order of the square root of the database size). It is also shown that for such queries, the algorithm is optimal. The matching upper and lower bounds are robust, in the sense that they hold under almost any reasonable rule (including the standard min rule of fuzzy logic) for evaluating the conjunction. Finally, we find a query that is provably hard, in the sense that the naive linear algorithm is essentially optimal.
Decreasing inequality under Latin America's "social democratic" and "populist" governments: is the difference real?

The article addresses the claim that the “left populist” governments of Argentina, Bolivia, Ecuador, and Venezuela failed to effectively reduce inequality in the 2000s. The author examines the econ...
Mesoscale Nanostructures as a Bridge Between Homogeneous and Heterogeneous Catalysis

The environment that surrounds catalytically active metallic nanoclusters has an important role in tuning their catalytic reactivity and selectivity and can initiate novel reaction routes. In this review we will demonstrate two different approaches for utilization of the environment in bi-functional, mesoscale catalysts. In these catalytic systems, the molecules that surround the metallic nanoclusters have an active role as co-catalysts. In the first bi-functional system, the steric effects of metal-adsorbed ligands have been exploited for regulating the adsorption orientation of reactants. By favoring specific orientation of the reactants, the products selectivity was widely tuned. In the second bi-functional catalytic system, the catalytic properties of the metallic nanoclusters were controlled by their encapsulation within a polymeric matrix. The oxidation state, catalytic reactivity and stability of metallic nanoclusters were tuned by their encapsulation in polyamidoamine dendrimer molecules. Oxidation of dendrimer-encapsulated nanoclusters into highly oxidized metal-ions activated the catalyst toward a variety of reactions which were previously catalyzed by homogeneous catalysts. Moreover, by modifying the properties of the polymeric matrix, enhanced chemo-, diastereo- and enantio-selectivity were obtained. These two examples of mesoscale catalysts indicate the important role of the surrounding environment in tuning the catalytic reactivity and selectivity. In addition, it is demonstrated that these catalysts can function as a bridge between homogeneous and heterogeneous catalysis.
Classical two-parabolic T -Schottky Groups

AT-Schottky group is a discrete group of Mobius transformations whose generators identify pairs of possibly-tangent Jordan curves on the complex sphere ℂ. If the curves are Euclidean circles, then the group is termed classicalT-Schottky.
Extracting the resolution algorithm from a completeness proof for the propositional calculus

Abstract We prove constructively that for any propositional formula ϕ in Conjunctive Normal Form, we can either find a satisfying assignment of true and false to its variables, or a refutation of ϕ showing that it is unsatisfiable. This refutation is a resolution proof of ¬ ϕ . From the formalization of our proof in Coq, we extract Robinson’s famous resolution algorithm as a Haskell program correct by construction. The account is an example of the genre of highly readable formalized mathematics.
Non-LTE kinetics modeling of krypton ions: Calculations of radiative cooling coefficients

Abstract For plasmas containing high-Z ions the energy loss due to radiative processes can be important in understanding energy distributions and spectral characteristics. Since high-Z plasmas occur over a wide range of temperature and density conditions, a general non-LTE population kinetics description is required to provide a qualitative and quantitative description for radiative energy loss. We investigate radiative properties of non-LTE krypton plasmas with a collisional–radiative (CR) model constructed from detailed atomic data. This work makes two extensions beyond previous non-LTE kinetics models. First, this model explicitly treats the dielectronic recombination (DR) channels. Second, this model allows one to investigate the higher electron density regimes found commonly in laboratory plasmas. This more comprehensive approach enables the study of population kinetics in a general manner and will provide a systematic guide for reducing a complex model to a simpler one. Specifically, we present the calculations of radiative cooling coefficients of krypton ions as a function of electron density in the optically thin limit. Total, soft X-ray (1.6 keV ≤ E ≤ 12 keV), and hard X-ray (E ≥ 12 keV) radiative cooling coefficients are given for the plasma conditions of 0.6 keV ≤ Te ≤ 10 keV and 1014 cm−3 ≤ Ne ≤ 1024 cm−3. The ionic radiative cooling coefficients provided are sufficient to allow users to construct the total rate from given charge state distributions. Steady-state calculations of the average charge state at given Te and Ne values are also presented.
The Croatian Collection at The New York Public Library

It is generally known that the New York Public Library (NYPL) is one of the most important repositories of Slavic intellectual and cultural documents, literature, and scholarly writings outside Europe. The specifics of the Croatian collection are not so well known, however. In an attempt to provide scholars with an overview of the NYPL's resources, this report describes the holdings of three of the Library's research divisions: the Slavic and Baltic Division, the General Research Division, and the Map Division, which are located at the Humanities and Social Sciences Library at Fifth Avenue and 42nd Street in Manhattan. Although the divisions function autonomously and are at a physical remove from each other within the institution, their Croatian holdings are uniformly cataloged within one electronic database (CATNYP), which can be accessed via the web at http://catnyp.nypl.org. This article was originally published by the Croatian Academy of America Inc. in the Journal of Croatian Studies, 1997, Vol. 38, ...
Refinement of Zinc Silicate Phosphor Synthesis

Zinc silicates are important in CRTs and lamp phosphors. Previous work has shown that a sol‐gel‐like method (termed CGUPS) can produce uniform zinc silicate phosphor particles whose surface layer possesses an appropriate activator concentration gradient and exhibits efficient cathodoluminescence (CL). This work further investigates this synthesis method in detail and verifies quantitatively the processing parameters for yielding optimal phosphors. Phosphors are evaluated as a function of starting silicic acid particle size ranges and activator (Mn) and coactivator (As) concentrations. Our results indicate that the CGUPS synthesis is not very sensitive to the processing parameters within their initially defined ranges. This study also demonstrates that the CL efficiency of phosphors does depend on particle size and is maximum for 4–7 and 7–12 μm size range with 10 keV electron excitation. For optimal CL efficiency and persistance, the Mn concentration is found to be 0.3% in terms of Mn/Zn ratio and the As/Mn ratio is 36%.
Spatial curvature falsifies eternal inflation

Inflation creates large-scale cosmological density perturbations that are characterized by an isotropic, homogeneous, and Gaussian random distribution about a locally flat background. Even in a flat universe, the spatial curvature measured within one Hubble volume receives contributions from long wavelength perturbations, and will not in general be zero. These same perturbations determine the Cosmic Microwave Background (CMB) temperature fluctuations, which are (10−5). Consequently, the low-l multipole moments in the CMB temperature map predict the value of the measured spatial curvature Ωk. On this basis we argue that a measurement of |Ωk| > 10−4 would rule out slow-roll eternal inflation in our past with high confidence, while a measurement of Ωk < −10−4 (which is positive curvature, a locally closed universe) rules out false-vacuum eternal inflation as well, at the same confidence level. In other words, negative curvature (a locally open universe) is consistent with false-vacuum eternal inflation but not with slow-roll eternal inflation, and positive curvature falsifies both. Near-future experiments will dramatically extend the sensitivity of Ωk measurements and constitute a sharp test of these predictions.
On combining machine learning with decision making

We present a new application and covering number bound for the framework of "Machine Learning with Operational Costs (MLOC)," which is an exploratory form of decision theory. The MLOC framework incorporates knowledge about how a predictive model will be used for a subsequent task, thus combining machine learning with the decision that is made afterwards. In this work, we use the MLOC framework to study a problem that has implications for power grid reliability and maintenance, called the Machine Learning and Traveling Repairman Problem (ML&TRP). The goal of the ML&TRP is to determine a route for a "repair crew," which repairs nodes on a graph. The repair crew aims to minimize the cost of failures at the nodes, but as in many real situations, the failure probabilities are not known and must be estimated. The MLOC framework allows us to understand how this uncertainty influences the repair route. We also present new covering number generalization bounds for the MLOC framework.
GPU-based fast cone beam CT reconstruction from undersampled and noisy projection data via total variation

Purpose: Cone-beam CT (CBCT) plays an important role in image guided radiation therapy (IGRT). However, the large radiation dose from serial CBCT scans in most IGRT procedures raises a clinical concern, especially for pediatric patients who are essentially excluded from receiving IGRT for this reason. The goal of this work is to develop a fast GPU-based algorithm to reconstruct CBCT from undersampled and noisy projection data so as to lower the imaging dose. Methods: The CBCT is reconstructed by minimizing an energy functional consisting of a data fidelity term and a total variation regularization term. The authors developed a GPU-friendly version of the forward-backward splitting algorithm to solve this model. A multigrid technique is also employed. Results: It is found that 20-40 x-ray projections are sufficient to reconstruct images with satisfactory quality for IGRT. The reconstruction time ranges from 77 to 130 s on an NVIDIA Tesla C1060 (NVIDIA, Santa Clara, CA) GPU card, depending on the number of projections used, which is estimated about 100 times faster than similar iterative reconstruction approaches. Moreover, phantom studies indicate that the algorithm enables the CBCT to be reconstructed under a scanning protocol with as low as 0.1 mA s/projection. Comparing with currentlymore » widely used full-fan head and neck scanning protocol of {approx}360 projections with 0.4 mA s/projection, it is estimated that an overall 36-72 times dose reduction has been achieved in our fast CBCT reconstruction algorithm. Conclusions: This work indicates that the developed GPU-based CBCT reconstruction algorithm is capable of lowering imaging dose considerably. The high computation efficiency in this algorithm makes the iterative CBCT reconstruction approach applicable in real clinical environments.« less
The Masses of Transition Circumstellar Disks: Observational Support for Photoevaporation Models

We report deep Submillimeter Array observations of 26 pre-main-sequence (PMS) stars with evolved inner disks. These observations measure the mass of the outer disk (r ~ 20-100 AU) across every stage of the dissipation of the inner disk (r < 10 AU) as determined by the IR spectral energy distributions (SEDs). We find that only targets with high mid-IR excesses are detected and have disk masses in the 1-5 MJup range, while most of our objects remain undetected to sensitivity levels of MDISK ~ 0.2–1.5 MJup. To put these results in a more general context, we collected publicly available data to construct the optical to millimeter wavelength SEDs of over 120 additional PMS stars. We find that the near-IR and mid-IR emissions remain optically thick in objects whose disk masses span 2 orders of magnitude (~0.5-50 MJup). Taken together, these results imply that, in general, inner disks start to dissipate only after the outer disk has been significantly depleted of mass. This provides strong support for photoevaporation being one of the dominant processes driving disk evolution.
Twisted skein homology

We apply the techniques of totally twisted Khovanov homology to Asaeda, Przytycki, and Sikora's construction of Khovanov type homologies for links and tangles in I-bundles over (orientable) surfaces. As a result we describe a chain complex built out of resolutions with only noncontractible circles whose homology is an invariant of the tangle. We use these to understand the δ-graded homology for links with alternating diagrams in the surface.
Strained-layer quantum well heterostructure lasers

Abstract Low threshold, high efficiency strained-layer InGaAsGaAsAlGaAs quantum well heterostructure lasers have been grown by metal-organic chemical vapor deposition. The metallurgical aspects of critical thickness in strained-layer heterostructure systems, the effects of strain and quantum size effect on emission wavelength, and considerations of threshold current density in strained-layer lasers are briefly outlined. Broad area InGaAsGaAs strained-layer heterostructure lasers having varying quantum well composition and thickness with respect to the critical thickness are described. The characteristics of optimized strained-layer InGaAsGaAs quantum well heterostructure lasers are presented.
Characteristics of Pool Boiling Bubble Dynamics in Bead Packed Porous Structures

Spherical glass and copper beads have been used to create bead packed porous structures for an investigation of two-phase heat transfer bubble dynamics under geometric constraints. The results demonstrated a variety of bubble dynamics characteristics under a range of heating conditions. The bubble generation, growth, and detachment during the nucleate pool boiling heat transfer have been filmed, the heating surface temperatures and heat flux were recorded, and theoretical models have been employed to study bubble dynamic characteristics. Computer simulation results were combined with experimental observations to clarify the details of the vapor bubble growth process and the liquid water replenishing the inside of the porous structures. This investigation has clearly shown, with both experimental and computer simulation evidence, that the millimeter scale bead packed porous structures could greatly influence pool boiling heat transfer by forcing a single bubble to depart at a smaller size, as compared with that in a plain surface situation at low heat flux situations, and could trigger the earlier occurrence of critical heat flux by trapping the vapor into interstitial space and forming a vapor column net at high heat flux situations. The results also proved data for further development of theoretical models of pool boiling heat transfer in bead packed porous structures.
Adaptive control of systems with backlash

Abstract We develop a mathematical model of backlash inverse and give a parametrization of the error caused by its estimate. We then design an adaptive backlash inverse controller for unknown plants with backlash and prove the global boundedness of the closed-loop signals. Simulations show major improvements of system performance.
Clinical experiences with mechanized cardiac massage

Abstract The important requisites for a mechanical pump for external cardiac massage have been described and are incorporated in a unit which has been evaluated during the past two and a half years. This instrument is portable, weighs only 31 pounds and is powered by oxygen or any other gas source. The ambulance model differs from the hospital model in that the exhaust oxygen is collected in a reservoir and then used to ventilate the lungs. Also, this model does not contain the optional feature of performing synchronized massage, which may be indicated when resuscitation is performed in the hospital. Both models permit the effective performance of external cardiopulmonary resuscitation by one person without incurring fatigue. The pump has been applied to many persons who sustained cardiac arrest. It produced adequate artificial circulation in each instance as manifested by a palpable peripheral pulse, a decrease in the size of the pupils, and the allowance of electrical conversion of ventricular fibrillation to a conducted beat. The most favorable cardiorespiratory factors appear to be a rate of 40 compressions/min., with a duration of systole one-third the cycle time, and with artificial ventilation being instituted between every other compression. It is most important that the artificial circulation not be interrupted for ventilatory or any other reasons. Clinical evidence could not be obtained to indicate that faster massage rates were better. Since the mechanical pump was never found to be less effective or more traumatic than manual massage, the many obvious advantages of mechanization warrant the substitution of the pump for the individual massager as soon as it is brought to the treatment area. The ultimate rate of salvage possible among patients sustaining cardiac arrest outside the operating room is not known. The solution of several questions currently apparent will undoubtedly influence the results; e.g., (1) should open-chest massage be used when the closed method appears unsuccessful, and when should it be instituted, (2) is it necessary to synchronize mechanical compression with electrical systole, and (3) is any advantage to be obtained by using adjunct supportive measures such as balloon occlusion of the abdominal aorta and internal diastolic pumping?
A model of the liquidity structure based on asset indivisibility

Abstract Although the notion of a liquidity structure of asset yields is widely accepted, there do not seem to be models of such a structure. Here, the liquidity of an asset is taken to be its transaction velocity, the amount traded per unit time divided by the stock. Assets are assumed to be indivisible and to differ in size. Trade using such assets is implied by pairwise matching and absence-of-double-coincidence in produced goods. It is shown that a sufficiently large asset has a lower velocity and a higher yield than a sufficiently small asset.
Engineering considerations of the advanced free-electron laser facility☆

Abstract The advanced free-electron laser (AFEL) is being built at Los Alamos inside a large existing laboratory building. In addition to cost and available space considerations, several engineering issues affected the design of the AFEL and its facility. The 1300 MHz, 20 MeV electron linac required extensive radiation shielding and a short rf-waveguide run. The free-electron laser (FEL) and photocathode-drive laser optics require a clean, constant temperature environment. New environmental, health, and safety (ESH compliance is now mandatory. The facility design included an earthquake restraint system for the radiation shielding, full compliance with the National Environmental Protection Act (NEPA), and minimization of airborne emissions.
Paget's disease of bone

Paget’s disease of bone is a focal disorder of unknown etiology characterized initially by excessive resorption and subsequently by excessive formation of bone, culminating in a “mosaic” pattern of lamellar bone associated with extensive local vascularity and increased fibrous tissue in adjacent marrow. In the strict sense this is not a metabolic bone disease, since some portion of the skeleton is spared, no matter how widespread the disease process may be. It is the extraordinary extent of the abnormal remodeling seen in some cases and its metabolic consequences that make necessary a detailed consideration of the disorder in this volume.
Synthesis of 2,6-dioxabicyclo[3.3.0]octenes by tandem ring-rearrangement/cross metathesis

Abstract A facile synthesis of stereodefined 2,6-dioxabicyclo[3.3.0]octene derivatives from the vinyl ether of endo -7-oxanorbornen-2-ol via tandem ring-opening/ring-closing(ring-rearrangement)/cross metathesis is reported.
Measurement of quasiparticle transport in aluminum films using tungsten transition-edge sensors

We report on experimental studies of phonon sensors which utilize quasiparticle diffusion in thin aluminum films connected to tungsten transition-edge-sensors (TESs) operated at 35 mK. We show that basic TES physics and a simple physical model of the overlap region between the W and Al films in our devices enables us to accurately reproduce the experimentally observed pulse shapes from x-rays absorbed in the Al films. We further estimate quasiparticle loss in Al films using a simple diffusion equation approach. These studies allow the design of phonon sensors with improved performance.
Price Subsidies, Diagnostic Tests, and Targeting of Malaria Treatment: Evidence from a Randomized Controlled Trial

Author(s): Dupas, Pascaline; Cohen, Jessica; Schaner, Simone | Abstract: Both under- and over-treatment of communicable diseases are public bads. But efforts to decrease one run the risk of increasing the other. Using rich experimental data on household treatment-seeking behavior in Kenya, we study the implications of this tradeoff for subsidizing life-saving antimalarials sold over-the-counter at retail drug outlets. We show that a very high subsidy (such as the one under consideration by the international community) dramatically increases access, but nearly half of subsidized pills go to patients without malaria. We study two ways to better target subsidized drugs: reducing the subsidy level and introducing rapid malaria tests over-the-counter.
Palladium-catalyzed stille couplings of aryl-, vinyl-, and alkyltrichlorostannanes in aqueous solution

Abstract Stille coupling of water-soluble aryl and vinyl halides with alkyl-, aryl-, and vinyltrichlorostannane derivatives (RSnCl 3 ) are effected in aqueous solution using a catalyst generated in situ from PdCl 2 and KOH both with and without added PhP( m -C 6 H 4 SO 3 Na) 2 . The yields are generally good to excellent, although some limitations of the protocol are described.
To Wet or Not to Wet: That Is the Question

Wetting transitions have been predicted and observed to occur for various combinations of fluids and surfaces. This paper describes the origin of such transitions, for liquid films on solid surfaces, in terms of the gas-surface interaction potentials V(r), which depend on the specific adsorption system. The transitions of light inert gases and H2 molecules on alkali metal surfaces have been explored extensively and are relatively well understood in terms of the least attractive adsorption interactions in nature. Much less thoroughly investigated are wetting transitions of Hg, H2O, heavy inert gases and other molecular films. The basic idea is that nonwetting occurs, for energetic reasons, if the adsorption potential’s well-depth D is smaller than, or comparable to, the well-depth e of the adsorbate-adsorbate mutual interaction. At the wetting temperature, Tw, the transition to wetting occurs, for entropic reasons, when the liquid’s surface tension is sufficiently small that the free energy cost in forming a thick film is sufficiently compensated by the fluid-surface interaction energy. Guidelines useful for exploring wetting transitions of other systems are analyzed, in terms of generic criteria involving the “simple model”, which yields results in terms of gas-surface interaction parameters and thermodynamic properties of the bulk adsorbate.
Thin Film Evaporation Using Nanoporous Membranes for Enhanced Heat Transfer

Recent advancements in integrated circuits demand the development of novel thermal management schemes that can dissipate ultra-high heat fluxes with high heat transfer coefficients. Previous study demonstrated the potential of thin film evaporation on micro/nanostructured surfaces [1–11]. Theoretical calculations indicate that heat transfer coefficients on the order of 106 W/m2K and heat fluxes of 105 W/cm2 can be achievable with water [1, 5–6]. However, in previous experimental setup, the coolant has to propagate across the surface which limits the increase in heat flux and the heat transfer coefficient, while adding complexity to the system design. This work aims to decouple the propagation of the coolant from the evaporation process through a novel experimental configuration. Thin nanoporous membranes of 13 mm diameter were used where a metal layer was deposited on the top surface to serve as a resistance heater. Liquid was supplied from the bottom of the membrane, driven through the nanopores by capillary force, and evaporated from the top surface. Heat transfer coefficient over 104 W/m2K was obtained with isopropyl alcohol (IPA) as the coolant, which is only two orders of magnitude smaller than the theoretical limit. This work offers insights into optimal experimental designs towards achieving kinetic limits of heat transfer for thin film evaporation based thermal management solutions.Copyright © 2012 by ASME
Moduli spaces of hyperelliptic curves with A and D singularities

We introduce moduli spaces of quasi-admissible hyperelliptic covers with at worst A and D singularities. The stability conditions for these moduli spaces depend on two rational parameters describing allowable singularities. For the extreme values of the parameters, we obtain the stacks of stable limits of $$A_n$$ and $$D_n$$ singularities, and the quotients of the miniversal deformation spaces of these singularities by natural $$\mathbb G _m$$ -actions. We interpret the intermediate spaces as log canonical models of the stacks of stable limits of $$A_n$$ and $$D_n$$ singularities.
Synthesis, intramolecular hydrogen bonding and conformation of optically active bilirubin amides. Analysis by circular dichroism and NMR

Abstract The conformation of the diamide and the bis-N-methylamide of an optically active analog of bilirubin (β S ,β′ S -dimethylmesobilirubin-XIIIα) is stabilized in a ridge-tile shape by intramolecular hydrogen bonding, as detected by 1 H-NMR and CD spectroscopy. The matrix of intramolecular hydrogen bonds resists disruption even in (CH 3 ) 2 SO solvent, where very strong exciton coupling CD is evident: Δϵ max 427 −417, Δϵ max 383 +234 (diamide).
Alkyl-alkenyl cross coupling via alkyl cobaloxime radical chemistry.An alkyl equivalent to the heck reaction compatible with common organic functional groups

Abstract A novel cobalt-mediated radical-olefin coupling reaction is described which regenerates the olefin functionality in the final product. The regeneration of olefin functionality is unique among radical-olefin couplings using simple activated alkenes.
Extracting facial features by an inhibitory mechanism based on gradient distributions

Abstract The extraction of facial features is a fundamental and crucial step in most face detection and recognition systems. Here a set of approaches are proposed for extracting internal and external facial features in a gray-level images containing single or multiple faces of various sizes, at different locations without any restriction on the background. These approaches are distinctive in several aspects: the use of some rarely exploited photometric properties as the basis of facial features extraction, a novel metrics on radial symmetry of gradient orientations, and an inhibitory mechanism for extracting internal facial features and a simple mechanism for external ones.
Higher alcohol and oxygenate synthesis over cesium-doped Cu/ZnO catalysts

Abstract The synthesis of higher (C+2) alcohols and esters has been studied over cesium-doped Cu ZnO catalysts. Under higher alcohol synthesis conditions, e.g., 583 K, 7.6 MPa, and gas hourly space velocity = 3260 liters (STP)/kg cat/hr with a H 2 CO = 0.45 synthesis gas, the presence of cesium promoted the formation of higher oxygenates, especially 2-methyl-1-propanol. The yields of products passed through distinct maxima at cesium nominal concentrations of 0.3–0.5%. These nominal concentrations generated optimum surface cesium concentrations of 15–25%. Under the reaction conditions employed, the principal role of cesium was to increase the ethanol synthesis rate and to provide an even greater enhancement in the rate of ethanol conversion to 1-propanol and subsequently to higher alcohols. To obtain insight into the mechanism of the carbon chain growth, e.g., C1 → C2, C2 → C3, and linear versus branched carbon chain growth, a 13C-NMR study of the C2C4 products formed over Cu ZnO and 0.4 mol% Cs/Cu/ZnO catalysts was performed. Separate injections into the CO H 2 synthesis gas of methanol and ethanol with natural-abundance 13C and enriched by 13C in specific positions showed that (i) lower alcohols were incorporated into the synthesis to form higher alcohols; (ii) carbon chain growth occurred in a stepwise manner dominated by the addition of oxygenated C1 intermediates at the β carbons of the oxygenated Cn (n ≥ 2) intermediates but also proceeding via linear addition Cn + C1 (n ≥ 1); and (iii) the presence of cesium had a dramatic effect on the reaction mechanism and promoted greatly the synthesis rates. The mechanistic effects of the alkali dopant were most pronounced in the C2 → C3 step. Over the Cu ZnO catalyst, injection of ethanol produced 1-propanol via linear chain growth, i.e., CH 3 13 CH 2 OH + CO H 2 → CH 3 13 CH 2 CH 2 OH . The presence of Cs effected a mechanistic switch and promoted β-carbon addition, CH 3 13 CH 2 OH + CO H 2 → 13 CH 3 CH 2 CH 2 OH . The position of the 13C label in the CH3 group of propanol provides evidence for retention of oxygen associated with the C1 intermediate, formed from CO H 2 , and loss of oxygen associated with the 13CH2OH group of ethanol. Mechanistically, such a retention is favored by a β-ketoalkoxide intermediate that is bonded to the cesium centers via its anionic oxygen. This unique mechanism is termed herein as aldol coupling with oxygen retention reversal and is specific to the presence of the cesium salt dopant. Higher alcohol synthetic steps C2 + C2 and Cn + Cm (n ≥ 3, m = 1, 2, 3) were also analyzed. Both oxygen retention reversal and normal oxygen retention were observed in coupling reactions leading to the higher-molecular-weight products (m + n > 3), and this observation is attributed to steric effects favoring the cis conformation of the β-alkoxide followed by rejection of either of its two oxygens.
The thinnest path problem

We formulate and study the thinnest path problem for secure communication in wireless ad hoc networks. The objective is to find a path from a source to its destination that results in the minimum number of nodes overhearing the message by a judicious choice of relaying nodes and their corresponding transmission powers. We adopt a directed hypergraph model of the problem and establish the NP-completeness of the problem in 2-D networks. We then develop two polynomial-time approximation algorithms that offer $\sqrt{{n\over 2}}$ and ${n\over 2\sqrt{n-1}}$ approximation ratios for general directed hypergraphs (which can model nonisotropic signal propagation in space) and constant approximation ratios for ring hypergraphs (which result from isotropic signal propagation). We also consider the thinnest path problem in 1-D networks and 1-D networks embedded in a 2-D field of eavesdroppers with arbitrary unknown locations (the so-called 1.5-D networks). We propose a linear-complexity algorithm based on nested backward induction that obtains the optimal solution for both 1-D and 1.5-D networks. This algorithm does not require the knowledge of eavesdropper locations and achieves the best performance offered by any algorithm that assumes complete location information of the eavesdroppers.
Paroxysmal nocturnal hemoglobinuria.

Purpose of reviewThe aim is to report on recent observations related to the natural history of paroxysmal nocturnal hemoglobinuria (PNH) and to review new therapeutic strategies for controlling the hemolysis of PNH.Recent findingsThis review focuses on studies designed to characterize the long-term
Low frequency quasi-normal modes of AdS black holes ∗

We calculate analytically low frequency quasi-normal modes of gravitational perturbations of AdS Schwarzschild black holes in d dimensions. We arrive at analytic expressions which are in agreement with their counterparts from linearized hydrodynamics in Sd−2 × , in accordance with the AdS/CFT correspondence. Our results are also in good agreement with results of numerical calculations.
Modulated Chemical Doping of Individual Carbon Nanotubes

Modulation doping of a semiconducting single-walled carbon nanotube along its length leads to an intramolecular wire electronic device. The nanotube is doped n-type for half of its length and p-type for the other half. Electrostatic gating can tune the system into p-n junctions, causing it to exhibit rectifying characteristics or negative differential conductance. The system can also be tuned into n-type, exhibiting single-electron charging and negative differential conductance at low temperatures. The low-temperature behavior is manifested by a quantum dot formed by chemical inhomogeneity along the tube.
Electron impact spectroscopy

The concepts of electron impact spectroscopy are discussed, comparing the electron spectroscopy techniques with those of the optical spectroscopy. The main advantage of the electron spectroscopy is to be found in the elimination of optical selection rules in excitation processes and the ability to scan the spectrum from the infrared to the X-ray region. The range of the method is indicated through a review of several examples, including electron impact excitation of Ba and rotational excitation of H2. The sensitivity of the method is demonstrated by vibrational excitation spectrum of N2. It is shown that the application of the method to the inner-shell excitation allows to obtain information about molecular species which are not commonly available, while spectroscopy of negative ions yields information about their energy and symmetry properties. However, the techniques are still under development and more data are expected to become available in the coming years.
Effects of Substrate Relaxation on Adsorption in Pores

Fluids in porous media are commonly studied with analytical or simulation methods, usually assuming that the host medium is rigid. By evaluating the substrate’s response (relaxation) to the presence of the fluid we assess the error inherent in that assumption. One application is a determination of the ground state of 3He in slit and cylindrical pores. With the relaxation, there results a much stronger cohesion than would be found for a rigid host. Similar increased binding effects of relaxation are found for classical fluids confined within slit pores or nanotube bundles.
Towards an understanding of decision complexity in IT configuration

In previous work we laid out an approach to quantifying configuration complexity [3]. In that earlier work, we explicitly focused on complexity as experienced by expert systems managers, and thus looked at straight-line configuration procedures, ignoring the complexity faced by non-experts as they have to decide what configuration steps to follow. Decision complexity is the complexity faced by a non-expert system administrator---the person providing IT support in a small-business environment, who is confronted by decisions during the configuration process, and is a measure of how easy or hard it is to identify the appropriate sequence of configuration actions to perform in order to achieve a specified configuration goal. To identify spots of high decisionmaking complexity, we need a model of decision complexity for configuring and operating computing systems. This paper extends previous work on models and metrics for IT configuration complexity by adding the concept of decision complexity. As the first step towards a complete model of decision complexity, we describe an extensive user study of decision making in a carefully-mapped analogous domain (route planning), and illustrate how the results of that study suggest an initial model of decision complexity applicable to IT configuration. The model identifies the key factors affecting decision complexity and highlights several interesting results, including the fact that decision complexity has significantly different impacts on user-perceived difficulty than on objective measures like time and error rate. We also describe some of the implications of our decision complexity model for system designers seeking to automate the decision-making and reduce the configuration complexity of their systems.
Pair excitations, collective modes, and gauge invariance in the BCS-Bose-Einstein crossover scenario

In this paper we study the BCS Bose-Einstein condensation ~BEC! crossover scenario within the superconducting state, using a T-matrix approach which yields the ground state proposed by Leggett. Here we extend this ground state analysis to finite temperatures T and interpret the resulting physics. We find two types of bosoniclike excitations of the system: long lived, incoherent pair excitations and collective modes of the superconducting order parameter, which have different dynamics. Using a gauge invariant formalism, this paper addresses their contrasting behavior as a function of T and superconducting coupling constant g .A t a more physical level, our paper emphasizes how, at finite T, BCS-BEC approaches introduce an important parameter D pg 5D 2 2D sc into the description of superconductivity. This parameter is governed by the pair excitations and is associated with particle-hole asymmetry effects that are significant for sufficiently largeg .I n the fermionic regime, D pg represents the difference between the square of the excitation gap D 2 and that of the superconducting order parameter D sc . The parameter D pg , which is necessarily zero in the BCS ~mean field! limit increases monotonically with the strength of the attractive interaction g. It follows that there is a significant physical distinction between this BCS-BEC crossover approach ~in which g is the essential variable which determines D pg) and the widely discussed phase fluctuation scenario in which the plasma frequency is the tuning parameter. Finally, we emphasize that in the strong coupling limit, there are important differences between the composite bosons that arise in crossover theories and the usual bosons of the ~interacting! Bose liquid. Because of constraints imposed on the fermionic excitation gap and chemical potential, in crossover theories, the fermionic degrees of freedom can never be fully removed from consideration.
COSMOLOGICAL CONSTRAINTS FROM GRAVITATIONAL LENS TIME DELAYS

Future large ensembles of time delay (TD) lenses have the potential to provide interesting cosmological constraints complementary to those of other methods. In a flat universe with constant w including a Planck prior, The Large Synoptic Survey Telescope TD measurements for ~4000 lenses should constrain the local Hubble constant h to ~0.007 (~1%), ? de to ~0.005, and w to ~0.026 (all 1? precisions). Similar constraints could be obtained by a dedicated gravitational lens observatory (OMEGA) which would obtain precise TD and mass model measurements for ~100 well-studied lenses. We compare these constraints (as well as those for a more general cosmology) to the optimistic Stage IV constraints expected from weak lensing, supernovae, baryon acoustic oscillations, and cluster counts, as calculated by the Dark Energy Task Force. TDs yield a modest constraint on a time-varying w(z), with the best constraint on w(z) at the pivot redshift of z 0.31. Our Fisher matrix calculation is provided to allow TD constraints to be easily compared to and combined with constraints from other experiments. We also show how cosmological constraining power varies as a function of numbers of lenses, lens model uncertainty, TD precision, redshift precision, and the ratio of four-image to two-image lenses.
From solidarity to division: An analysis of Lech Wałęsa's transition to constituted leadership

Abstract This essay analyzes the capacity and constraints of authority in the contexts of constituted vs. non-constituted leadership. Using the experience of Lech Walesa's transition from the leader of the Solidarity social movement to the president of Poland as a case study, this article evaluates the portability of leadership skills and informal authority to the changing operational context of constituted leadership. It argues that the constraints of formal authority are significantly higher than those imposed on non-constituted leaders. As a result, while constituted leaders may have greater resources available to broadcast power, the allocation of these resources entails higher expectation for their custodians. This analysis concludes that a successful transition from non-constituted to constituted leadership is possible only when the leader manages to build new bases of informal authority. Walesa failed to expand his informal authority and was unsuccessful at transferring his leadership skills to the presidency.
Plasmid‐directed mechanisms for bacteriophage defense in lactic streptococci

Genetic studies with lactic streptococci have identified a variety of plasmids coding for systems that interfere with phage adsorption, direct restriction and modification activities, and disrupt various stages in the phage lytic cycle. This review describes mechanisms of phage defense that are plasmid-directed in lactic streptococci, examines the physical and genetic properties of the plasmids involved, and discusses genetic strategies for construction of phage-insensitive starter cultures for dairy fermentations.