cssi/SciSciGPT-SciSciNet huggingface dataset:
Pilot-wave dynamics in a rotating frame: on the emergence of orbital quantization

We present the results of a theoretical investigation of droplets walking on a rotating vibrating fluid bath. The droplet’s trajectory is described in terms of an integro-differential equation that incorporates the influence of its propulsive wave force. Predictions for the dependence of the orbital radius on the bath’s rotation rate compare favourably with experimental data and capture the progression from continuous to quantized orbits as the vibrational acceleration is increased. The orbital quantization is rationalized by assessing the stability of the orbital solutions, and may be understood as resulting directly from the dynamic constraint imposed on the drop by its monochromatic guiding wave. The stability analysis also predicts the existence of wobbling orbital states reported in recent experiments, and the absence of stable orbits in the limit of large vibrational forcing.
Classification and existence of doubly-periodic instantons

We present a classification of SU(2) instantons on T 2 × R 2 according to their asymptotic behaviour. We then study the existence of such instantons for different values of the asymptotic parameters, uncovering some surprising non-existence results. We also describe explicitly the moduli space for unit charge.
Quantitative analogy between polymer-grafted nanoparticles and patchy particles

We establish a quantitative analogy between polymer grafted nanoparticles (PGNPs) and patchy nanoparticles (NPs). Over much of the experimentally relevant parameter space, we show that PGNPs behave quantitatively like Janus NPs, with the patch size having a universal dependence on the number of grafts and the ratio of the size of the NPs to the grafted chain size. The widely observed anisotropic self-assembly of PGNP into superstructures can thus be understood through simple geometric considerations of single patch models, in the same spirit as the geometry-based surfactant models of Israelachvili.
Continuous robust control design for nonlinear uncertain systems without a priori knowledge of control direction

In this paper, a robust control scheme is proposed for a class of nonlinear systems that have not only additive nonlinear uncertainties but also unknown multiplicative signs. These signs are called control directions since they represent effectively the direction of motion under any given control. Except for the unknown control directions, the class of systems satisfy the generalized matching conditions. Nonlinear robust control is designed to identify on-line unknown control directions and to guarantee global stability of uniform ultimate boundedness without the knowledge of nonlinear dynamics except their size bounding functions. It is also shown that the proposed robust control can be made continuous through utilizing the so-called shifting laws that change smoothly and accordingly the signs of robust controls and that, no matter what time constants and gains of the shifting laws are, global stability is always ensured. The analysis and design is done using Lyapunov's direct method. >
Time Resolution of a Scintillation Counter System

Time resolution of a scintillation counter system composed of scintillator, light pipe, multiplier phototube, discriminator, and coincidence circuit is discussed. The discriminator and coincidence circuits can produce coincidence curves with edges as steep as 10 psec per decade. Multiplier phototubes are capable of similar resolution. providing they view sufficiently bright, well-defined light flashes. In a time-of-flight measurement at the Berkeley 184-inch Cyclotron, the coincidence curve slope, measured from a counting rate of 50% to 5%, is 400 psec per decade. The light level corresponds to 2000 electrons reaching the first dynode of the multiplier phototube. A slope of 200 psec per decade would be expected if only the multiplier phototube and electronics were considered. Geometry and rate of light output of the scintillator are believed to limit system resolution at present.
Augmenting the Condenser Heat-Transfer Performance of Rotating Heat Pipes

A rotating heat pipe assembly was tested at rotational speeds of 700, 1400, and 2800 rpm using distilled water as the working fluid. Tests were made during film condensation on several copper condensers, including smoothwalled cylinders, an internally finned cylinder, and a truncated cone. The truncated cone surface was also promoted for dropwise condensation using n-octadecyl mercaptan in octanoic acid. Heat-transfer performance improved with increasing rotational speed. The internally finned cylinder and the truncated cone showed a 100% improvement over the equivalent smooth-walled cylinder. Dropwise condensation showed substantial improvement over film condensation, primarily at low rotational speeds. Nomenclature cp = specific heat gc = gravitational constant m = mass rate of flow Q = heat-transfer rate R = radius AT = cooling water temperature difference p = density a = surface tension o> = angular velocity
Migrants’ International Transfers and Educational Expenditure: Empirical Evidence from Albania

The primary objective of this article is to cast some light upon the relationship between education expenditure and the volume of remittances sent to Albania from abroad by international migrants. To assess the existence of an education enhancing effect of remittances, an Engel curve framework is used. In addition, quintile regression analysis is employed to investigate whether migrants’ remittances have a differentiated effect on various quantiles of the conditional distribution of education consumption. The two main empirical findings are that household income has a positive and well-determined impact on education expenditure, whereas international transfers do not influence education spending.
Transformation Toughening in Large‐Grain‐Size CeO2‐Doped ZrO2 Polycrystals

The fracture and transformation behavior of tetragonal polycrystalline ZrO2 alloys containing 18 mol% CeO2 (Ce-TZP) was investigated. In the absence of applied stress the tetragonal phase was found to be stable in large-grained (>30 μm) samples at room temperature. The monoclinic phase was detected in regions of high residual stress near hardness indentations although no evidence of a wake of monoclinic phase along the fracture surface was observed. The fracture toughness increased from 4 to 7 MPa · m1/2 as density and/or grain size increased. It is proposed that the relatively high toughness of these materials is due to the occurrence of stress-driven tetragonal-to-monoclinic transformation near the crack tip, which reverses when the crack has passed.
Cosmic Rays from Gamma Ray Bursts in the Galaxy

The rate of terrestrial irradiation events by Galactic gamma-ray bursts (GRBs) is estimated using recent standard-energy results. We assume that GRBs accelerate high-energy cosmic rays, and we present results of three-dimensional simulations of cosmic rays moving in the Galactic magnetic field and diffusing through pitch-angle scattering. An on-axis GRB extinction event begins with a powerful prompt γ-ray and neutron pulse, followed by a longer lived phase from cosmic-ray protons and neutron-decay protons that diffuse toward Earth. Our results force a reinterpretation of reported ~1018 eV cosmic-ray anisotropies and offer a rigorous test of the model in which high-energy cosmic rays originate from GRBs, and this model will soon be tested using the Auger Observatory.
The noncentrosymmetric chain compounds, A3M2AsSe11 (A = K, Rb, Cs; M = Nb, Ta)

Abstract The noncentrosymmetric niobium and tantalum selenoarsenates, A3Nb2AsSe11 (A=K, Rb, Cs) and K3Ta2AsSe11, were synthesized in a polyselenoarsenate flux. All compounds crystallize in the polar monoclinic space group Cc. The structures are comprised of the same type of infinite chain anions, [M2Se2(Se2)3(AsSe3)]3− (M=Nb, Ta) separated by alkali metal cations. The As3+ centers with nonbonded electron pairs play an important role in stabilizing the noncentrosymmetric structures. UV-Vis spectroscopy, Raman spectroscopy and differential thermal analysis data are reported. The energy gaps of these compounds vary between 1.35 and 1.53 eV.
Trade Costs and the Gains from Trade in Crop Agriculture

We develop a simulation model of world crop markets that is based upon Ricardian comparative advantage. We apply the model to twenty-three countries and provide measures of the degree of globalization in this sector, the gains from trade, and the elasticity of trade volumes to trade costs. The distribution of the gains from trade across countries is uneven due to important differences in openness to imports, productivity, and other factors, some of which appear to be related to a country’s level of development. Distance limits the extent by which changes in one country are transmitted to others.
A pipelined architecture for logic programming with a complex but single-cycle instruction set

Abstract An architecture is described which executes logic programs using fewer instruction cycles than hardware implementations of the Warren Abstract Machine or the Berkeley SPUR augmented with a Prolog coprocessor. This is achieved by balancing the characteristics of CISC and RISC architectures. Specifically, this architecture provides support for the semantics of logic programs using complex instructions and multiple pipelined functional units. Examples of complex instructions include partial unify, push and load reference, pop and dereference and switch on type ; all typically execute in a single clock cycle from a full pipeline. Conditional instruction execution reduces branch frequency to 0.09%, which keeps the pipeline full and allows 16-way memory interleaving. Under these conditions, one LIBRA processor using 100 ns memory is estimated to execute nine million logical inferences per second.
Targeting DNA repair pathways for cancer treatment: what’s new?

ABSTRACT: Disruptions in DNA repair pathways predispose cells to accumulating DNA damage. A growing body of evidence indicates that tumors accumulate progressively more mutations in DNA repair proteins as cancers progress. DNA repair mechanisms greatly affect the response to cytotoxic treatments, so understanding those mechanisms and finding ways to turn dysregulated repair processes against themselves to induce tumor death is the goal of all DNA repair inhibition efforts. Inhibition may be direct or indirect. This burgeoning field of research is replete with promise and challenge, as more intricacies of each repair pathway are discovered. In an era of increasing concern about healthcare costs, use of DNA repair inhibitors can prove to be highly effective stewardship of R&D resources and patient expenses.
I’m Proud of It: Consumer Technology Appropriation and Psychological Ownership

While a common narrative is that we are increasingly living in a “technology-mediated” world, a quick assessment of emerging digital technologies suggests that today’s standards will soon seem old-fashioned and quaint. For example, advances in circuitry, flexible displays, projection, and wearable computing promise to literally and figuratively weave technology into the fabric of our lives.
Synthesis, resolution, and aldol reactions of a planar-chiral Lewis acid complex.

The synthesis and resolution of a new planar-chiral Lewis acid complex is described. The compound is applied to asymmetric Mukaiyama aldol reactions, leading to the formation of the desired product with good stereoselectivity. The sense of stereoselection is as predicted by the design, which exploits the ability of the Lewis acid to simultaneously serve as a σ and a π acceptor. Mechanistic observations are consistent with rate-determining formation of an aldehyde−Lewis acid complex, followed by rapid nucleophilic addition.
The effects of N-methylation on the enantioselectivity of catalysis by cyclo[(R)-His-(R)-Phe]

Abstract The cyclic dipeptide cyclo[( R )-His-( R )-Phe] 1 has been known since 1981 to catalyze the enantioselective formation of cyanohydrins from aldehydes and HCN. Although 1 has proved to be very effective in the production of optically active cyanohydrins, the precise structure of its catalytically active form remains unresolved. Two derivatives, in which the two amides in 1 were independently N -methylated, were synthesized as probes of the structural and functional requirements for catalysis by 1 . Both derivatives were far more soluble in organic solvents and were found to catalyze the formation of racemic cyanohydrin, but differed greatly in their turnover rates. Mixtures of the two derivatives with each other and with 1 were also examined as hydrocyanation catalysts. Only the mixtures containing 1 demonstrated any enantioselectivity, but did not appear any more competent as catalysts than reduced quantities of 1 . From these data, it is concluded that both amide bonds are essential for effective catalysis by 1 , but that the amide containing the His N α appears to be involved in interactions with the substrate while the other amide plays a structural role, possibly for self-associative hydrogen bonding.
Did You Get Your Shots? Experimental Evidence on the Role of Reminders

Many families fail to vaccinate their children despite the supply of these services at no cost. This study tests whether personal reminders can increase demand for vaccination. A field experiment was conducted in rural Guatemala in which timely reminders were provided to families whose children were due for a vaccine. The six-month intervention increased the probability of vaccination completion by 2.2 percentage points among all children in treatment communities. Moreover, for children in treatment communities who were due to receive a vaccine, and whose parents were expected to be reminded about that due date, the probability of vaccination completion increased by 4.6 percentage points. The cost of an additional child with complete vaccination due to the intervention is estimated at about $7.50.
Supporting range queries on web data using k-nearest neighbor search

A large volume of geospatial data is available on the web through various forms of applications. However, access to these data is limited by certain types of queries due to restrictive web interfaces. A typical scenario is the existence of numerous business web sites that provide the address of their branch locations through a limited "nearest location" web interface. For example, a chain restaurant's web site such as McDonalds can be queried to find some of the closest locations of its branches to the user's home address. However, even though the site has the location data of all restaurants in, for example, the state of California, the provided web interface makes it very difficult to retrieve this data set. We conceptualize this problem as a more general problem of running spatial range queries by utilizing only k-Nearest Neighbor (k-NN) queries. Subsequently, we propose two algorithms to cover the rectangular spatial range query by minimizing the number of k-NN queries as possible. Finally, we evaluate the efficiency of our algorithms through empirical experiments.
Dynamic rates of return to education in the U.S.

Abstract This paper develops dynamic and expected dynamic rates of return to high school and college education for males and females for 1967–95 that take the effects of annual changes in institutional costs and in real earnings within each age group in cross section age earnings profiles into account. As such they are more comparable to total returns on financial assets. Based on Current Population Survey data, and on adjustments for net “ability” bias from recent studies of identical twins, it is shown that the standard rates of return underestimate the returns to college in 1995 by 3 percentage points for male college graduates and 5 percentage points for females. Assuming that recent trends are based on underlying technical change, globalization, and other factors that are likely to persist, these expected dynamic rates averaged 13.3% in real terms or 11.7% if corrected for ability, family factors, and for measurement error.
Synthesis and biological evaluation of novel cytotoxic phospholipids for prostate cancer

We describe herein synthesis, SAR, and biological evaluation of a novel series of cytotoxic serine amide phosphates (SAPs) for prostate cancer. These compounds were tested for their cytotoxicity in five human prostate cancer cell lines (DU-145, PC-3, LNCaP, PPC-1, and TSU), and in CHO and RH7777 cells (negative controls). Comparison of anticancer effects of these compounds with a standard chemotherapeutic agent 5-fluorouracil shows that they are very effective in killing prostate cancer cells with low micromolar cytotoxicity and provide us a new lead for the development of drugs for prostate cancer.
A macroeconomic model with a financial sector

This paper studies a macroeconomic model in which financial experts borrow from less productive agents. We pursue four sets of results: (i) The economy is prone to instability and occasionally enters volatile episodes. As volatility spikes agents precautionary motive increases depressing prices even further. Log-linear approximations fail to capture these non-linear effects that can cause economies to be significantly depressed for long periods of time. (ii) Endogenous risk during volatile episodes increases asset price correlations. (iii) Financial experts impose a negative externality on each other and on the labor sector by not maintaining adequate capital cushion, and funding structure. (iv) While risk sharing within the financial sector (through securitization and derivatives contracts) reduces many inefficiencies, it can also amlify systemic risks.
Shear-Induced Diffusion in Dilute Suspensions of Charged Colloids

We propose a model for the nonequilibrium enhancement of colloidal self‐diffusion in an externally imposed shear flow in charged systems. The diffusion enhancement is calculated in terms of electrostatic, two‐body interactions between the particles in shear flow. In the high‐shear rate, low‐volume fraction limit in which the model is valid, we compare these calculations to the experiments of Qiu et al. [PRL 61, 2554 (1988)] and simulations of Chakrabarti et al. [PRE 50, R3326 (1994)] and find good agreement on scaling and magnitude to within experimental uncertainty of the electrostatic parameters.
Presidential Coattails in 1972

Because Richard Nixon's overwhelming victory in the 1972 presidential election was not accompanied by any significant increase in Republican representation in Congress, it has been assumed that his coattails were exceedingly short. However, analysis of several kinds of evidence suggests that such an assumption is premature and that Nixon's pulling power has been underestimated. An explanation of the failure of Republican gains to materialize as congressional seats may be found in the competitive disadvantages suffered by Republicans in a period of increasingly safe seats. Gary C. Jacobson is Associate Professor of Political Science at Trinity College, Hartford. POQ 40 (1976) pp. 194-200 This content downloaded from 207.46.13.114 on Thu, 26 May 2016 06:05:03 UTC All use subject to http://about.jstor.org/terms PRESIDENTIAL COATTAILS IN 1972 195 fall took many of them down with him. His "coattails" operated only negatively. Or so it appears. But such asymmetry is not satisfying; it compels us to take another look at presidential coattails in 1972. As Miller explained some years ago, untangling true coattail effects from other determinants of voting is no simple matter;2 neither aggregate nor survey data provide unambiguous results. Thus the data analysis reported below does not, by itself, sustain the case for significant coattail effects in 1972; but it shows how presidential and congressional voting tended to vary together and suggests that dismissal of the possibility has
Convergence to Rational Expectations in a Stationary Linear Game

This paper describes several learning processes which converge, with probability one, to the rational expectations (Bayesian-Nash) equilibrium of a stationary linear game. The learning processes include a test for convergence to equilibrium, and a method for changing the parameters of the process when non-convergence is indicated. This self-stabilization property eliminates the need to impose stability conditions on the economic environment. Convergence to equilibrium is proved for two types of self-stabilizing learning mechanisms: a centralized forecasting mechanism and a decentralized strategy adjustment process.
III-V compounds and their applications

The III-V compounds and their alloys offer a unique combination of new electrical and optical properties. The available variety of band structure allows these materials to compete for electronic and optical functions not accessible to the elemental semiconductors.
Nonlinear differential-geometric techniques for control of a series DC motor

The problem of controlling a series DC motor using only current measurements is considered. It is shown that both speed and load-torque may be estimated from the current measurements. Two nonlinear feedback laws are considered based on feedback linearization and input-output linearization, respectively. Both of these control laws require knowledge of the speed and load-torque. The speed/torque estimation scheme and the control schemes are valid in the presence of magnetic saturation in the field circuit and when high-speed field-weakening is employed. By neglecting the armature inductance, the estimation is accomplished using nonlinear state-space and output-space transformations to construct an observer with linear error-dynamics whose rate of convergence may be arbitrarily specified. (Such an observer could provide reliability to existing systems in the event of a speed sensor failure.) The feedback-linearization controller involves a nontrivial state-space transformation allowing control of the full state trajectory. An input-output linearization controller with stable internal dynamics is also explicitly constructed. Finally, simulations are given to demonstrate the algorithms. >
Metallicity Evolution in the Early Universe.

Observations of the damped Lyα systems provide direct measurements on the chemical enrichment history of neutral gas in the early universe. In this Letter, we present new measurements for four damped Lyα systems at high redshift. Combining these data with [Fe/H] values culled from the literature, we investigate the metallicity evolution of the universe from z ≈ 1.5 to 4.5. Contrary to our expectations and the predictions of essentially every chemical evolution model, the N(H I)-weighted mean [Fe/H] metallicity exhibits minimal evolution over this epoch. For the individual systems, we report tentative evidence for an evolution in the unweighted [Fe/H] mean and the scatter in [Fe/H], with the higher redshift systems showing lower scatter and lower typical [Fe/H] values. We also note that no damped Lyα system has [Fe/H] < -2.7 dex. Finally, we discuss the potential impact of small number statistics and dust on our conclusions and consider the implications of these results on chemical evolution in the early universe.
Benzo[1,2-c:3,4-c']bis[1,2,5]selenadiazole, [1,2,5]selenadiazolo-[3,4-e]-2,1,3-benzothiadiazole, furazanobenzo-2,1,3 -thiadiazole, furazanobenzo-2,1,3-selenadiazole and related heterocyclic systems

The first synthesis of benzo[1,2-c:3,4-c']bis[1,2,5]selenadiazole has been developed starting from commercially available 4-nitrobenzo-2,1,3-selenadiazole. Improved syntheses of the related heterocycles [1,2,5]selenadiazolo[3,4-e]-2,1,3-benzothiadiazole, furazanobenzo-2,1,3-thiadiazole and furazanobenzo-2,1,3-selenadiazole are also reported.
Spontaneous regression of cancer

Spontaneous regression of cancer is one of the most fascinating phenomena observed in medicine. It is generally regarded as inexplicable, although there are now some laboratory studies of regressed or regressing tumours, as well as new theoretical possibilities about mechanisms. In this review, the historical background, clinical features and possible mechanisms are discussed. The clinical aspects of the malignancies most often reported to undergo spontaneous regression, namely renal cell carcinoma, neuroblastoma, carcinoma of the breast, malignant melanoma and leukaemias/lymphomas, are reviewed. The prevalent view regarding the mechanism for spontaneous regression is the involvement of immunological factors in the host. Other mechanisms include hormonal changes, tumour necrosis, trauma and changes in blood supply. Recent. reports suggest other mechanisms such as apoptosis and differentiation to a benign tumour. Decreased telomerase activity has been reported in neuroblastomas that regress, and hypomethylation of DNA in retinoblastoma is a possibility. A role for cytokines and/or growth factors is also discussed. The significance of spontaneous regression is the demonstration of endogenous control of neoplastic growth. Spontaneous regression of cancer is defined as the complete or partial disappearance of malignant tumour in the absence of therapy that is capable of inducing anti-neoplastic effects. Most patients ultimately relapse, so it is not usually associated with cure of the malignant disease. The existence of spontaneous regression is often questioned; indeed, review of the literature reveals reported cases which do not represent malignant disease, instances in which documentation of metastases is questionable and some reported cases in which therapy may have played a role. In 1966, Everson and Cole published a classic monograph on this topic which included 176 well- documented cases of spontaneous regression of cancer published from 1900 until 1964, and listed criteria for the diagnosis (1). These are: documented histologic regression of biopsy-proven metastases; radiologic regression of
Symmetry restoration and tachyon condensation in open string theory

It has recently been argued that D-branes in bosonic string theory can be described as noncommutative solitons, outside whose core the tachyon is condensed to its ground state. We conjecture that, in addition, the local U(1) gauge symmetry is restored to a U(∞) symmetry in the vacuum outside this core. We present new solutions obeying this boundary condition. The tension of these solitons agrees exactly with the expected D-brane tension for arbitrary noncommutativity parameter θ, which effectively becomes a dynamical variable. The restored U(∞) eliminates unwanted extra modes which might otherwise appear outside the soliton core.
Local controllability for a “swimming” model.

We study the local controllability of a mathematical model of an abstract object which "swims" in the 2-D nonstationary Stokes fluid. We assume that this object consists of finitely many subsequently connected small sets ("thick points") each of which can act upon any of the adjacent sets in a rotation fashion with the purpose to generate its fish- or snakelike motion. We regard the magnitudes of the respective rotation forces, entering the system's equations as coefficients, as multiplicative (or bilinear) controls. The structural integrity of the object is maintained by the elastic forces acting between the aforementioned adjacent sets according to Hooke's law. Models like this are of a interest in biology and engineering applications dealing with propulsion systems in fluids.
Gold(I)‐Catalyzed Cycloisomerization of 2‐Fluoroalk‐3‐yn‐1‐ones: Synthesis of 2,5‐Substituted 3‐Fluorofurans

Fluorination of 1,4-disubstituted tert-butyldimethylsilyl but-1-en-3-yn-1-yl ethers with Selectfluor gives 2-mono-fluorobut-3-yn-1-ones. Subsequent 5-endo-dig cyclization in the presence of chlorotriphenylphosphine gold(I)/silver trifluoromethanesulfonate (both 5 mol%, dichloromethane) under ambient conditions, provides a facile method for the generation of mainly 2,5-diaryl-substituted 3-fluorofurans in high yields (89―96%). The structure of 2-(4-bromophenyl)-3-fluoro-5-(4-methylphenyl)furan was confirmed by X-ray crystallography.
Maximum a posteriori estimation for SPECT using regularization techniques on massively parallel computers

Single photon emission computed tomography (SPECT) reconstructions performed using maximum a posteriori (penalized likelihood) estimation with the expectation maximization algorithm are discussed. Due to the large number of computations, the algorithms were performed on a massively parallel single-instruction multiple-data computer. Computation times for 200 iterations, using I.J. Good and R.A. Gaskins's (1971) roughness as a rotationally invariant roughness penalty, are shown to be on the order of 5 min for a 64*64 image with 96 view angles on an AMT-DAP 4096 processor machine and 1 min on a MasPar 4096 processor machine. Computer simulations performed using parameters for the Siemens gamma camera and clinical brain scan parameters are presented to compare two regularization techniques-regularization by kernel sieves and penalized likelihood with Good's rotationally invariant roughness measure-to filtered backprojection. Twenty-five independent sets of data are reconstructed for the pie and Hoffman brain phantoms. The average variance and average deviation are examined in various areas of the brain phantom. It is shown that while the geometry of the area examined greatly affects the observed results, in all cases the reconstructions using Good's roughness give superior variance and bias results to the two alternative methods. >
Mixed-Mode Crack Propagation in Functionally Graded Materials

This paper presents numerical simulation of mixed-mode crack propagation in functionally graded materials by means of a remeshing algorithm in conjunction with the finite element method. Each step of crack growth simulation consists of the calculation of the mixedmode stress intensity factors by means of a non-equilibrium formulation of the interaction integral method, determination of the crack growth direction based on a specific fracture criterion, and local automatic remeshing along the crack path. A specific fracture criterion is tailored for FGMs based on the assumption of local homogenization of asymptotic crack-tip fields in FGMs. The present approach uses a user-defined crack increment at the beginning of the simulation. Crack trajectories obtained by the present numerical simulation are compared with available experimental results.
Highest weight modules and polarized embeddings of shadow spaces

The present paper was inspired by the work on polarized embeddings by Cardinali et al. (J. Algebr. Comb. 25(1):7---23, 2007) although some of our results in it date back to 1999. They study polarized embeddings of certain dual polar spaces, and identify the minimal polarized embeddings for several such geometries. We extend some of their results to arbitrary shadow spaces of spherical buildings, and make a connection to work of Burgoyne, Wong, Verma, and Humphreys on highest weight representations for Chevalley groups. Let Δ be a spherical Moufang building with diagram M over some index set I, whose strongly transitive automorphism group is a Chevalley group $G(\mathbb{F})$ over the field $\mathbb{F}$ . For any non-empty set K?I let Γ be the K-shadow space of Δ. Extending the notion in to this situation, we say that an embedding of Γ is polarized if it induces all singular hyperplanes. Here a singular hyperplane is the collection of points of Γ not opposite to a point of the dual geometry Γ ?, which is the shadow geometry of type opp I (K) opposite to K. We prove a number of results on polarized embeddings, among others the existence of (relatively) minimal polarized embeddings. We assume that $G(\mathbb{F})$ is untwisted. In that case, the point-line geometry Γ has an embedding e K into the Weyl module $V(\lambda_{K})_{\mathbb{F}}^{0}$ of highest weight ? K =? k?K ? k . We show that this embedding is polarized in the sense described above. We then prove that the minimal polarized embedding relative to e K exists and equals the unique irreducible $G(\mathbb{F})$ -module L(? K ) of highest weight ? K . More precisely we show that the polar radical of e K (the intersection of all singular hyperplanes) coincides with the radical of the contravariant bilinear form considered by Wong to obtain the irreducible (restricted) representations of $G(\mathbb{F})$ in positive characteristic. This viewpoint allows us to "recognize" the irreducible $G(\mathbb{F})$ -modules of highest weight ? K geometrically as minimal polarized embeddings of the appropriate shadow space.
Real-space and energy representations for the interface-roughness scattering in quantum-well structures

We show that the real space representation of the interface roughness as a fluctuating potential in the coordinate space is equivalent to the usual energy-fluctuation representation for intrasublevel scattering in multi-interface quantum well structures with generally shaped confinement-potential profiles. The coordinate picture is, however, more general and can be used for higher-order effects and multi-sublevel scattering in tunnel-coupled multi-quantum-well structures. The result is employed to study the interface-roughness-limited mobility of tunnel-coupled double quantum wells at low temperatures.
Ballistic Transport in Metallic Nanotubes with Reliable Pd Ohmic Contacts

Contacting metallic single-walled carbon nanotubes by palladium (Pd) affords highly reproducible ohmic contacts and allows for the detailed elucidation of ballistic transport in metallic nanotubes. The Pd ohmic contacts are more reliable than the titanium (Ti) previously used for ballistic nanotube devices. In contrast, Pt contacts appear to give nonohmic contacts to metallic nanotubes. For both ohmic and nonohmic contacts, the length of the nanotube under the metal contact area is electrically turned off. Transport occurs from metal to nanotube at the edges of the contacts. Measurements with large numbers of Pd-contacted nanotube samples reveal that the mean free path for defect scattering in SWNTs grown by chemical vapor deposition can be up to 4 Im. The mean free paths for acoustic phonon scattering are on the order of 500 nm at room temperature and .4 Im at low temperatures. Ohmic contacts with minimum contact resistance are important to the fundamental characterization and realization of high-performance devices of electronic materials. Ohmic contacts to individual metallic single-walled carbon nanotubes (m-SWNTs) by Cr and Ti have enabled the observation
Free radical reactions for heterocycle synthesis. Part 7: 2-Bromobenzoic acids as building blocks in the construction of spirobenzolactones and spirobenzolactams

A straightforward 2-step parallel synthesis for structurally diversified spiro compounds is developed. 2-Bromobenzoic acids are used as common building blocks to couple with a series of conjugated enoles or enamines. Sequential intramolecular free radical Michael additions lead to formation of spirobenzolactones, spirobenzolactams, spirobenzolactone-lactams, spiorbenzolactone-thiolactones, spiordilactones, and bridged-spirolactones.
Preparation of Silicon Nitride‐Titanium Nitride and Titanium‐Titanium Nitride Composites from (CH3)3SiNHTiCl3‐Coated Si3N4 and Ti Particles

[(Trimethylsilyl)amino]titanium trichloride, (CH{sub 3}){sub 3}-SiNHTiCl{sub 3}, was isolated as a red-orange crystalline solid in 58% Yield from the reaction of TiCl{sub 4} with [(CH{sub 3}){sub 3}Si]{sub 2} NH in 1:1 molar ratio in dichloromethane at {minus}78 C. Pyrolysis of (CH{sub 3}){sub 3}SiNHTiCl{sub 3} at 600 C furnished titanium nitride. This precursor is suitable for the preparation of composites and was employed to prepare Si{sub 3}N{sub 4}-TiN and Ti-TiN powders by adding Si{sub 3}N{sub 4} particles or titanium powders to a solution of (CH{sub 3}){sub 3} SiNHTiCl{sub 3} in dichloromethane, drying and pyrolyzing the resulting solid. This precursor also has been used as a binder to prepare Si{sub 3}N{sub 4}-TiN and Ti-TiN bodies. High-resolution transmission electron microscopic studies of the Si{sub 3}N{sub 4}-TiN composite showed that titanium nitride is concentrated on the surface of the Si{sub 3}N{sub 4} particles.
Learning in Multi-Robot Systems

This paper discusses why traditional reinforcement learning methods often result in poor performance in dynamic, situated multiagent domains characterized by multiple goals, noisy perception and action, and inconsistent reinforcement. We propose a methodology for designing the representation and the forcement functions that take advantage of implicit domain knowledge in order to accelerate learning in such domains, and demonstrate it experimentally in two different mobile robot domains.
Construction of a double-layered tetrahedral network within a perovskite host: Two-step route to the alkali-metal-halide layered perovskite, (LixCl)LaNb2O7

A two-step topotactic route is used to construct lithium halide layers within a perovskite host. Initially RbLaNb2O7 is converted to (CuCl)LaNb2O7 by ion exchange and then reductive intercalation with n-butyllithium is used to form (LixCl)LaNb2O7. The copper metal byproduct from the reduction step is removed by treatment with iodine. Rietveld refinement of neutron powder diffraction data revealed that an alkali-halide double layer with LiO2Cl2 tetrahedra forms between the perovskite slabs. Compositional studies indicate that the range for x in (LixCl)LaNb2O7 is 2⩽x<4, which appears consistent with the neutron data where only one lithium site was found in the structure.
Distortions to world trade: impacts on agricultural markets and farm incomes

The authors provide estimates of the impact that removing all merchandise trade distortions (including agricultural subsidies) would have on food and agricultural production, trade, and incomes. Using the latest versions of the Global Trade Analysis Project (GTAP) database and the World Bank's LINKAGE model of the global economy (projected to 2015), their results suggest farm employment, the real value of agricultural output and exports, the real returns to farm land and unskilled labor, and real net farm incomes would all rise substantially in developing country regions with a move to free merchandise trade, thereby alleviating rural poverty-despite the decline in international terms of trade for developing countries that are net food importers or are enjoying preferential access to agricultural markets of high-income countries.
Employment of second order ruled surfaces in design of sheet beam guns

A novel 3D method of sheet beam (SB) gun design has recently been developed [1]. Second order ruled surfaces (SORS) to define the geometry of the gun electrodes. The gun design process is made simpler if SORS are derived from analytical formulas. A proposed method is discussed and illustrated.
Order ideals and a generalized Krull height theorem

Let N be a finitely generated module over a Noetherian local ring (R,m). We give criteria for the height of the order ideal N*(x) of an element x ∈ N to be bounded by the rank of N. The Generalized Principal Ideal Theorem of Bruns, Eisenbud and Evans says that this inequality always holds if x ∈ mN. We show that the inequality even holds if the hypothesis becomes true after first extending scalars to some local domain and then factoring out torsion. We give other conditions in terms of residual intersections and integral closures of modules. We derive information about order ideals that leads to bounds on the heights of trace ideals of modules—even in circumstances where we do not have the expected bounds for the heights of the order ideals!
Turbulent shear flows of variable density.

Abstract : A study was made of the mean flow field of free turbulent layers of variable density showing that if the velocity distribution in a particular constant-density flow is known, it is possible to obtain the corresponding variable-density velocity field without the introduction of a compressible turbulent viscosity. This is accomplished by a Dorodnitsyn-Howarth type of transformation applied to the time-dependent equations of motion rather than to the mean equations of motion, as has been done previously. When the transformed equations are averaged, using Reynolds' method, the incompressible turbulent equations for the mean flow are obtained. These equations can then be handled by conventional methods. Predictions obtained by this procedure agree well with experimental results.
Early martian dynamo generation due to giant impacts

Abstract During late-stage planet formation, giant impacts produce localized mantle melt regions within which impactor iron droplets settle to the bottom near a permeability horizon. After accumulation, iron heated by the impact migrates downward to the core through colder, mostly solid mantle. The degree of thermal equilibration and partitioning of viscous heating between impactor iron and silicates depends on the mechanism of iron transport to the core. Simple estimates suggest that, following a giant impact, the temperature difference between iron delivered to the core and the mantle outside the impact heated region can be ∼10 3 K. Hot impactor iron mergers with the core where it may be efficiently mixed or remain stratified due to thermal buoyancy. In either case, collisional energy carried to the core by impactor iron helps establish conditions favorable for early core cooling and dynamo generation. In this study, we consider the end-member scenario in which impactor iron forms a layer at the top of the core. Energy transfer from the impactor iron layer to the mantle is sufficient to power a dynamo for up to ∼30 Myr even in the limit of a very viscous mantle and heat flux limited by conduction. Using two-dimensional finite element calculations of mantle convection, we show that large-scale mantle flow driven by the buoyancy of the impact thermal anomaly focuses plumes in the impact region and increases both dynamo strength and duration. Melting within the mantle thermal boundary layer likely leads to formation of a single superplume in the location of the impact anomaly driven upwelling. We suggest that formation of magnetized southern highland crust may be related to spreading and differentiation of an impact melt region during the impact-induced dynamo episode.
Legal Challenges in Government Imposition of Water Conservation: The Kansas Example

This article deals with legal challenges in conserving water in the United States, using Kansas as an example. The focus is on one aspect of American water allocation law—the extent to which a state can force reductions in pumping by holders of water rights. It explains the hybrid nature of water rights, which on the one hand are “real property rights,” and yet on the other hand they are viewed as rights only to use water and not to own the water itself. Because they are a kind of property right, they are protected by the fifth amendment to the U.S. Constitution against “takings” by the government without compensation. The ques tion becomes: to what extent, then, can states demand reductions in pumping without having to pay compensation? The answer is difficult for both water right holders and government officials to predict. The law of groundwater rights in Kansas illustrates the problem. The article describes the Kansas law in the context of other states on this issue, including the historic changes in Kansas’ water law doctrines, water management under the appropriation doctrine, the public trust doctrine, groundwater management districts, and intensive groundwater use control areas, as well as recent attempts to foster voluntary actions by water right holders that avoid government imposition of restrictions. Questions remain in Kansas and elsewhere about where the line can be drawn, between acceptable government restrictions and unacceptable takings of property. Future drought caused by climate change will focus even more attention on this question.
The Core Structure of Presolar Graphite Onions

Of the "presolar particles" extracted from carbonaceous meteorite dissolution residues, i.e., of those particles that show isotopic evidence of formation in the neighborhood of other stars prior to the origin of our solar system, a subset of the onion-like graphite spheres has an interesting concentric graphene core-graphite rim structure. We show here that single graphene sheet defects in the onion cores (e.g., cyclopentane loops) may be observable edge-on by high-resolution electron microscopy. This could allow a better evaluation of models for their formation and in particular could strengthen the possibility that growth of these assemblages proceeds atom by atom with the aid of such in-plane defects, under conditions of growth (e.g., radiation fluxes or grain temperature) that discourage the graphite layering that dominates subsequent formation of the graphite rims.
Screening for Depression in the Primary Care Population

Despite strong efforts, the diagnosis and treatment of depression bring many challenges in the primary care setting. Screening for depression has been shown to be effective only if reliable systems of care are in place to ensure appropriate treatment by clinicians and adherence by patients. New evidence-based models of care for depression exist, but spread has been slow because of inadequate funding structures and conflicts within current clinical culture. The Affordable Care Act introduces potential opportunities to reorganize funding structures, conceivably leading to increased adoption of these collaborative care models. Suicide screening remains controversial.
Inspection of through silicon vias (TSV) and other interconnections in IC packages by computed tomography

Through silicon vias (TSV) as used in 3D integrated electronic packages were inspected non-destructively by highly resolving nanofocus computed tomography (nanoCT). In particular, in the TSVs plating voids were visualised and quantitatively evaluated by numerical processing of the resulting volumetric data. The nanoCT technology is outlined and further applications such as interposers etc. are considered.
A new mechanism for the generation of quasi‐zonal jets in the ocean

[1] A simple barotropic quasi-geostrophic model is used to demonstrate that instabilities radiated from an unstable eastern boundary current can generate zonal striations in the ocean interior with realistic wavelengths and amplitudes. Nonlinear transfer of energy from the more unstable trapped modes is important for radiating modes to overcome friction. The dynamics shown here are generic enough to point to the eastern boundary current as a likely source of the observed striations extending from oceanic eastern boundaries.
Computational Analysis of Stall and Separation Control in Centrifugal Compressors

A three-dimensional compressibleNavier ‐Stokes code has been used to model thesteady and unsteady e owe eld within a low-speed centrifugal compressor cone guration tested at NASA Lewis Research Center. Near-design conditions, the performance map, pressure e eld, and the velocity e eld were in good agreement with measured data. At off-design conditions, the calculations show that e ow reversal e rst occurs near the blade leading edge. If leftunchecked,thereversed-e owregiongrowsspatiallyandtemporally.Injectionofairupstreamofthecompressor face was found to modify the local e ow near the blade leading edge and to suppress rotating stall and surge. Even a moderate amount of air, typically around 5% of the total mass e ow rate, was sufe cient to extend the useful operating range of the compressor.