cssi/SciSciGPT-SciSciNet huggingface dataset:
A comparison of the photocatalytic activity of six tunneled titanates

The photocatalytic behavior of six tunneled titanates—Na{sub 0.7}Ga{sub 4.7}Ti{sub 0.3}O{sub 8}, Na{sub 0.8}Ga{sub 4.8}Ti{sub 1.2}O{sub 10}, Na{sub 0.8}Ga{sub 4.8}Ti{sub 2.2}O{sub 12}, K{sub 1}Ga{sub 17}Ti{sub 15}O{sub 56}, K{sub 1.5}Ga{sub 1.5}Ti{sub 6.5}O{sub 16}, and BaTi{sub 4}O{sub 9}—was investigated using methylene blue as an indicator and a xenon arc lamp as the radiation source. Powders prepared by solid state reaction had surface areas ranging from 0.40 to 1.58 m{sup 2}/g and particle sizes ranging from 1 to 25 μm. Bandgaps, as measured from diffuse reflectance data, ranged from 2.84 to 4.15 eV. Two of the tunneled titanates—Na{sub 0.8}Ga{sub 4.8}Ti{sub 1.2}O{sub 10} and Na{sub 0.7}Ga{sub 4.7}Ti{sub 0.3}O{sub 8}—exhibited negligible photocatalytic activity. The activities of Na{sub 0.8}Ga{sub 4.8}Ti{sub 2.2}O{sub 12}, KGa{sub 17}Ti{sub 15}O{sub 56}, and K{sub 1.5}Ga{sub 1.5}Ti{sub 6.5}O{sub 16} were similar to each other, exhibiting apparent first-order reaction rates of 0.275 to 0.31 h{sup −1} using 100 mg of powder in 125 ml of 20 μM methylene blue at room temperature. The BaTi{sub 4}O{sub 9} sample exhibited the highest photocatalytic activity with an apparent first-order reaction rate of 0.53 h{sup −1} under the same conditions. The addition of a RuO{sub 2} co-catalyst improved the photocatalytic activity of Na{sub 0.7}Ga{sub 4.7}Ti{sub 0.3}O{sub 8}, decreased themore » activity of BaTi{sub 4}O{sub 9}, and had little effect on the activity of the other powders. A comparison of the structural features in the six materials shows that photocatalytic activity is strongly related to the density of TiO{sub 6} octahedra in the different crystal structures. Among the gallium-containing tunneled titanates, photocatalytic activity increased with decreasing band gap. - Graphical abstract: Na{sub 0.7}Ga{sub 4.7}Ti{sub 0.3}O{sub 8}—One of the tunneled titanates investigated. Highlights: ► The photocatalytic activity of six tunneled titanates was compared. ► Na{sub 0.8}Ga{sub 4.8}Ti{sub 1.2}O{sub 10} and Na{sub 0.7}Ga{sub 4.7}Ti{sub 0.3}O{sub 8} exhibited negligible photocatalytic activity. ► The activities of Na{sub 0.8}Ga{sub 4.8}Ti{sub 2.2}O{sub 12}, KGa{sub 17}Ti{sub 15}O{sub 56}, and K{sub 1.5}Ga{sub 1.5}Ti{sub 6.5}O{sub 16} were similar to each other. ► BaTi{sub 4}O{sub 9} exhibited the highest photocatalytic activity. ► Photocatalytic activity is related to the density of TiO{sub 6} octahedra.« less
Deconstructing de Sitter

Semiclassical gravity predicts that de Sitter space has a finite entropy. We suggest a picture for Euclidean de Sitter space in string theory, and use the AdS/CFT correspondence to argue that de Sitter entropy can be understood as the number of degrees of freedom in a quantum mechanical dual.
Development of a Corrosion Resistant Directionally Solidified Material for Land Based Turbine Blades

Advanced turbines with improved efficiency require materials that can operate at higher temperatures, Availability of these materials would minimize cooling flow requirements, and, thus, improve the efficiency of a turbine. Advanced processing, such as directional solidification (DS), can improve temperature capability of the majority of Ni based superalloys. However, results of earlier work on IN-738 reveal that the DS process does not significantly improve temperature capability of this alloy, A research program was initiated to develop a corrosion resistant Ni-based DS blade material for land based turbines. In this program, eight heats with varied Cr, Al, Ti, Ta, and W contents were selected for evaluation. Screening tests performed on these heats in the DS condition include tensile, creep, and corrosion. The results of experimental heats were compared with those of IN-738 in the equiaxed condition. From these results, two chemistries offering approximately 100°F temperature advantage at typical row I turbine blade operating stress were selected for castability and further mechanical property evaluation. Several row I solid and cored turbine blades were successfully cast. The blades were evaluated for grain structure and mechanical properties. Tests were also conducted to evaluate the effects of withdrawal rates on properties. These results are summarized in this paper.
Efficient copper-catalyzed coupling of aryl chlorides, bromides and iodides with aqueous ammonia

The copper(I)-catalyzed synthesis of a range of primary anilines from electron-rich and electron-deficient aryl halides including aryl chlorides has been achieved with aqueous ammonia, avoiding the need for inert atmosphere, expensive catalysts and ligands, anhydrous solvents, and additional base or other additives.
Thrust measurements and flow field analysis of a piezoelectrically actuated oscillating cantilever

Although not identical to the motion employed by nature’s swimmers and flyers, the simple harmonic oscillations of cantilever-like structures have been shown to provide efficient low-power solutions for applications ranging from thermal management to propulsion. However, in order to quantify their true potential, the resulting flow field and corresponding thrust must be better understood. In this work, a thin, flexible cantilever is actuated via a piezoelectric patch mounted near its base and caused to vibrate in its first resonance mode in air. The flow field is experimentally measured with particle image velocimetry while the thrust produced from the oscillatory motion is quantified using a high-resolution scale. The trends observed in the data are captured using an oscillating Reynolds number, and a clear relationship is defined between the operating parameters and the resulting thrust. Two-dimensional flow fields are extracted from the x–y and y–z planes and are primarily used to motivate future geometry and sidewall configurations that could greatly enhance the thrust capabilities of the cantilever by directing the flow downstream in a more effective manner.
Topology of Evolving Networks: Local Events and Universality

Networks grow and evolve by local events, such as the addition of new nodes and links, or rewiring of links from one node to another. We show that depending on the frequency of these processes two topologically different networks can emerge, the connectivity distribution following either a generalized power law or an exponential. We propose a continuum theory that predicts these two regimes as well as the scaling function and the exponents, in good agreement with numerical results. Finally, we use the obtained predictions to fit the connectivity distribution of the network describing the professional links between movie actors.
Results following resection for stage IV gastric cancer; are better outcomes observed in selected patient subgroups?

Background Patients who present with stage IV gastric cancer are not commonly managed with surgical resection as effective palliation can usually be accomplished with systemic chemotherapy, endoscopic stenting, or surgical bypass procedures. Given the inherent morbidity and mortality associated with gastrectomy, palliative resection for stage IV gastric cancer should be reserved for ideal surgical candidates who are most likely to benefit from the procedure. The purpose of this study is to review outcomes following resection for stage IV gastric cancer, and to identify criteria predictive of improved outcomes following gastrectomy in this setting. Methods A retrospective review of a prospective GI oncology database was conducted. Sixty-three patients with stage IV gastric cancer managed with surgical resection between 1989 and 2001 were identified. Variables including demographic data, patterns of distant spread (ex: peritoneal, lymphatic, hematogenous), location of tumor, and type of gastrectomy were utilized to conduct survival analyses. Results Actuarial survival for all patients at one and 3-year intervals was 52% and 12%, respectively. Improved survival was observed for patients of East Asian race (median survival 20 vs. 12 months, P < 0.05, students t-test) and age less than 60 years (median survival 15 vs. 12 months, P < 0.05). This trend was also illustrated by Kaplan–Meier survival analysis. Other variables including pattern of distant spread, location of tumor, and type of gastrectomy were not associated with a significant difference in survival. Both East Asian race and age less than 60 years were statistically significant predictors of improved survival when assessed by univariate regression analysis. When variables were analyzed in a multivariate regression analysis, Asian race and age <60 both lost their statistical significance as independent predictors of improved survival. Conclusions Long-term survival for patients with stage IV gastric cancer who are managed with surgical resection is achievable. Patient specific variables including East Asian race and age less than 60 years appear to be associated with prolonged survival when assessed by comparison of means, Kaplan–Meier analysis, and univariate regression analysis. However, multivariate regression analysis failed to demonstrate these factors as independent predictors of improved outcome. In conclusion, highly selected acceptable risk surgical candidates with stage IV gastric cancer should be considered for management with surgical resection in clinically appropriate scenarios. J. Surg. Oncol. 2007;95:118–122. © 2007 Wiley-Liss, Inc.
Absorption of dilaton partial waves by D3-branes

Abstract We calculate the leading term in the low-energy absorption cross section for an arbitrary partial wave of the dilaton field by a stack of many coincident D3-branes. We find that it precisely reproduces the semiclassical absorption cross section of a 3-brane geometry, including all numerical factors. The crucial ingredient in making the correspondence is the identification of the precise operators on the D3-brane world-volume which couple to the dilaton field and all its derivatives. The needed operators are related through T -duality and the IIA/M-theory correspondence to the recently determined M(atrix) theory expressions for multiple moments of the 11D supercurrent. These operators have a characteristic symmetrized trace structure which plays a key combinatorial role in the analysis for the higher partial waves. The results presented here give new evidence for an infinite family of non-renormalization theorems which are believed to exist for two-point functions in N =4 gauge theory in four dimensions.
The combining DAG: a technique for parallel data flow analysis

As the number of available multiprocessors increases, so does the importance of providing software support for these systems, including parallel compilers. Data flow analysis, an important component of software tools, may be computed many times during the compilation of a program, especially when compiling for a multiprocessor. Although converting a sequential data flow algorithm to a parallel algorithm can present some opportunities for computing data flow in parallel, more parallelism can be exposed by the development of new parallel data flow algorithms. We present a technique that computes rapid data flow problems in parallel and thus is applicable for commonly used classical data flow problems, including reaching definitions, reachable uses, available expressions, and very busy expressions. Unlike previous techniques, our technique exploits the inherent parallelism in the data flow computation that occurs across independent paths, within linear paths, and in paths through loops of a control flow graph. The technique first changes cyclic structures in a control flow graph to acyclic structures and then builds a combining directed acyclic graph (DAG) that represents the paths through the control flow graph needed to compute data flow. Data flow is then computed using two passes over the DAG by computing the data flow for the nodes on each level of the DAG in parallel. We also present experimental results comparing the performance of our algorithm with a sequential algorithm and a parallelized sequential algorithm. >
Local duality and nonleptonic B decay

Abstract In the large Nc limit, the nonleptonic width of the B meson is determined by the lepton mass spectrum in semileptonic B decay and the hadron mass spectrum in τ decay. This result can be compared with the nonleptonic width computed using the operator product expansion and local duality, to estimate the violation of local duality in B decay. In the absence of the required data, we use experimental Monte Carlo predictions and find that the difference is small, at the few percent level. We estimate the theoretical uncertainty in our results from higher order corrections (including 1/Nc effects). We also identify a new contribution to the Λb−B lifetime difference.
Ownership and Participation in Transitional Justice Mechanisms: A Sustainable Human Development Perspective from Eastern DRC

1 Sustainable human development principles underlie many of the objectives of transitional justice mechanisms. At the same time, the form, implementation and outcome of such mechanisms are influenced primarily by the political will, capacity and resources available to local, national and international institutions. Missing in the equation is the active involvement of the affected population in the planning and implementation phases. Building on the concepts of participation and ownership core to the philosophy and practice of sustainable human development, we use the results of a survey of 2,620 adult residents in eastern Democratic Republic of Congo to illustrate how transitional justice policies could and should be grounded in empirical evidence to best achieve sustainable human development objectives. Our results suggest that basic survival needs and security must come before mechanisms that deal with justice issues and reparations. Respondents expressed fear of reprisal if they were to talk openly about their experience in the conflict, which poses an obstacle to any truth-seeking process and, more generally, social change. In addition, the population's expectations for punishment and prosecution of numerous defendants must be addressed. Transitional justice mechanisms must be part of a broader set of policies for socioeconomic development and reconciliation.
DUALITIES IN 4D THEORIES WITH PRODUCT GAUGE GROUPS FROM BRANE CONFIGURATIONS

Abstract We study brane configurations which correspond to N=1 field theories in four dimensions. By inverting the order of the NS 5-branes and D6-branes, a check on dualities in four dimensional theories can be made. We consider a brane configuration which yields electric/magnetic duality for gauge theories with SO(Nc1)×Sp(Nc2) product gauge group. We also discuss the possible extension to any alternating product of SO and Sp groups. The new features arising from the intersection of the NS 5-branes on the orientifold play a crucial role in our construction.
Changes in Cascading Failure Risk with Generator Dispatch Method and System Load Level

Industry reliability rules increasingly require utilities to study and mitigate cascading failure risk in their system. Motivated by this, this paper describes how cascading failure risk, in terms of expected blackout size, varies with power system load level and pre-contingency dispatch. We used Monte Carlo sampling of random branch outages to generate contingencies, and a model of cascading failure to estimate blackout sizes. The risk associated with different blackout sizes was separately estimated in order to separate small, medium, and large blackout risk. Results from N − 1 secure models of the IEEE RTS case and a 2383 bus case indicate that blackout risk does not always increase with load level monotonically, particularly for large blackout risk. The results also show that risk is highly dependent on the method used for generator dispatch. Minimum cost methods of dispatch can result in larger long distance power transfers, which can increase cascading failure risk.
A sample of quasars with strong nitrogen emission lines from the sloan digital sky survey

We report on 293 quasars with strong N IV] λ1486 or N III] λ1750 emission lines (rest-frame equivalent width >3 A) at 1.7 < z < 4.0 selected from the Sloan Digital Sky Survey (SDSS) Fifth Data Release. These nitrogen-rich (N-rich) objects comprise ~1.1% of the SDSS quasars. The comparison between the N-rich quasars and other quasars shows that the two quasar subsets share many common properties. We also confirm previous results that N-rich quasars have much stronger Lyα and N V λ1240 emission lines. Strong nitrogen emission in all ionization states indicates high overall nitrogen abundances in these objects. We find evidence that the nitrogen abundance is closely related to quasar radio properties. The radio-loud fraction in the N III]-rich quasars is 26% and in the N IV]-rich quasars is 69%, significantly higher than ~8% measured in other quasars with similar redshift and luminosity. Therefore, the high nitrogen abundance in N-rich quasars could be an indicator of a special quasar evolution stage, in which the radio activity is also strong.
Implicit and conservative difference scheme for the Fokker-Planck equation

Abstract An implicit and fully conservative finite-difference scheme is proposed for solving the Fokker-Planck equation for Coulomb collisions between isotropically distributed like particles in a spatially homogeneous plasma. The scheme extends the standard Chang-Cooper method by providing not only number density conservation, but also energy conservation. As a result, time steps much larger than the thermal collision time can be used to stably and accurately simulate plasmas far from thermal equilibrium. Such a relaxation in time-step constraint has allowed for the successful implementation of the new scheme in multidimensional transport Fokker-Planck codes, with a resulting increase in computational efficiency.
An iron-mediated approach to o-aryloxyanisoles

Abstract The monomethoxylation of (1,2-dichlorobenzene)cyclopentadienyliron hexafluorophosphate, followed by phenoxylation utilizing a variety of variously substituted phenols, is shown to be an effective method for the synthesis of o-aryloxyanisole complexes.
BLISS for SPICA: far-IR spectroscopy at the background limit

We present concepts for the background-limited infrared-submillimeter spectrograph (BLISS) for the Japanese SPICA mission to launch early next decade. SPICA will be a 3.5-meter telescope cooled to below 5 K, and offers the potential for far-IR observations limited only by the zodiacal dust emission. BLISS will provide moderate-resolution (R 1000) spectroscopy at this background limit throughout the 40-600 μ m band. With sensitivities below 10 -20 Wm 2 in modest integrations, BLISS-SPICA will enable the first survey spectroscopy of the redshift 0.5 to 5 galaxies which produce the far-IR background. Both WaFIRS waveguide grating spectrometers, and new compact cross-dispersed echelle grating designs are under consideration. Detectors must have sensitivities around 3x10 -20 W/√Hz and have good efficiency. The most promising near-term approaches to cover the full band are transition-edge bolometers cooled to ~50 mK with an adiabatic demagnetization refrigerator.
Dependence of Galaxy Shape on Environment in the Sloan Digital Sky Survey

Using a sample of galaxies from the Sloan Digital Sky Survey Data (SDSS) Release 4, we study the trends relating surface brightness profile type and apparent axis ratio to the local galaxy environment. We use the SDSS parameter "fracDeV" to quantify the profile type (fracDeV = 1 for a pure de Vaucouleurs profile, fracDeV = 0 for a pure exponential profile). We find that galaxies with Mr -18 are mostly described by exponential profiles in all environments. Galaxies with -21 Mr -18 mainly have exponential profiles in low-density environments and de Vaucouleurs profiles in high-density environments. The most luminous galaxies, with Mr -21, are mostly described by de Vaucouleurs profiles in all environments. For galaxies with Mr -19, the fraction of de Vaucouleurs galaxies is a monotonically increasing function of local density, while the fraction of exponential galaxies is monotonically decreasing. For a fixed surface brightness profile type, the apparent axis ratio is frequently correlated with environment. As the local density of galaxies increases, we find that for Mr ∈ [-18, - 20], galaxies of all profile types become slightly rounder, on average. For Mr ∈ [-20, - 22], galaxies with mostly exponential profiles tend to become flatter, while galaxies with de Vaucouleurs profiles tend to become rounder. For Mr ∈ [-22, - ∞], galaxies with mostly exponential profiles become flatter, while the de Vaucouleurs galaxies become rounder in their inner regions, yet exhibit no change in their outer regions. We comment on how the observed trends relate to the merger history of galaxies.
Autonomous Control of Micro Aircraft Vehicles Falling Through an Atmospheric Boundary Layer

A trajectory control problem for simple micro air vehicles (MAVs) is introduced and studied. The MAVs are endowed with the ability to estimate their position and velocity and can control their drag coefficient. The objective of this work is to design a control law for the drag coefficient in order to land the MAV close to a desired streamwise location, after being dropped from an airborne carrier at low altitude. We use a simple model-predictive control law, relying on a two-dimensional time-averaged atmospheric velocity field, which is validated on an unsteady three-dimensional representation of an unstratified atmospheric boundary layer. The simulation results show that the proposed control law results in a significant (10-fold) improvement in the accuracy of the streamwise landing point location, with respect to the uncontrolled case. Similar results are obtained when errors are considered in the location of the release point and in the estimate of the mean flowfield.
A generalized Bogomolov–Gieseker inequality for the three-dimensional projective space

A generalized Bogomolov–Gieseker inequality for tilt-stable complexes on a smooth projective threefold was conjectured by Bayer, Toda, and the author. We show that such inequality holds true in general if it holds true when the polarization is sufficiently small. As an application, we prove it for the three-dimensional projective space.
Legitimacy and Justice in Republican Perspective

Let justice be a feature of the social order imposed by a state and legitimacy a feature of how it is imposed: one that makes the imposition acceptable. This article argues that, so understood, legitimacy is quite a distinct concern from justice; that the core concern is with showing how state coercion is consistent with people’s being free citizens; that this does not require showing that the state exists by consensus or contract; that the best hope of satisfying the concern lies with arguing that state coercion need not be dominating; and that this is possible only within the republican theory that identifies freedom with the absence of domination, not interference.
Angular resolution study of a combined gamma-neutron coded aperture imager for standoff detection

Abstract Nuclear threat source observables at standoff distances of tens of meters from mCi class sources include both gamma-rays and neutrons. This work uses simulations to investigate the effects of the angular resolution of a mobile gamma-ray and neutron coded aperture imaging system upon orphan source detection significance and specificity. The design requires maintaining high sensitivity and specificity while keeping the system size as compact as possible to reduce weight, footprint, and cost. A mixture of inorganic and organic scintillators was considered in the detector plane for high sensitivity to both gamma-rays and fast neutrons. For gamma-rays (100 to 2500 keV) and fission spectrum neutrons, angular resolutions of 1–9° and radiation angles of incidence appropriate for mobile search were evaluated. Detection significance for gamma-rays considers those events that contribute to the photopeak of the image pixel corresponding the orphan source location. For detection of fission spectrum neutrons, energy depositions above a set pulse shape discrimination threshold were tallied. The results show that the expected detection significance for the system at an angular resolution of 1° is significantly lower compared to its detection significance an angular resolution of ∼3–4°. An angular resolution of ∼3–4° is recommended both for better detection significance and improved false alarm rate, considering that finer angular resolution does not result in improved background rejection when the coded aperture method is used. Instead, over-pixelating the search space may result in an unacceptably high false alarm rate.
Linking impulse response functions to reaction time: Rod and cone reaction time data and a computational model

Reaction times for incremental and decremental stimuli were measured at five suprathreshold contrasts for six retinal illuminance levels where rods alone (0.002–0.2 Trolands), rods and cones (2–20 Trolands) or cones alone (200 Trolands) mediated detection. A 4-primary photostimulator allowed independent control of rod or cone excitations. This is the first report of reaction times to isolated rod or cone stimuli at mesopic light levels under the same adaptation conditions. The main findings are: 1) For rods, responses to decrements were faster than increments, but cone reaction times were closely similar. 2) At light levels where both systems were functional, rod reaction times were ~20 ms longer. The data were fitted with a computational model that incorporates rod and cone impulse response functions and a stimulus-dependent neural sensory component that triggers a motor response. Rod and cone impulse response functions were derived from published psychophysical two-pulse threshold data and temporal modulation transfer functions. The model fits were accomplished with a limited number of free parameters: two global parameters to estimate the irreducible minimum reaction time for each receptor type, and one local parameter for each reaction time versus contrast function. This is the first model to provide a neural basis for the variation in reaction time with retinal illuminance, stimulus contrast, stimulus polarity, and receptor class modulated.
Space-Time Analysis of GDP Disparities among European Regions: A Markov Chains Approach:

The purpose of this article is to study the evolution of GDP disparities among 138 European regions over the period from 1980 to 1995. Regional per capitaGDPcross-sectional distribution is characterized by means of nonparametric estimations of density functions, and the growth process is modeled as a first-order stationary Markov chain. Spatial effects are then introduced within the Markov chain framework using regional conditioning and spatial Markov chains. The results of the analysis indicate the persistence of regional disparities, a progressive bias toward a poverty trap, and the importance of geography in the convergence process.
Branes and inflationary cosmology

Abstract We discuss a brane based inflationary scenario in which an initially non-supersymmetric configuration involving a D4 brane is dynamically transformed into a supersymmetric one in a background space–time geometry determined by a stack of D6 branes. Inflation is realized in the effective four-dimensional theory and ends after reaching a stable BPS configuration. The scalar spectral index turns out to be 0.98. Under some simplifying assumption the reheat temperature, Hubble constant and the string scale are estimated to be of order 10 8 GeV, 10 12 GeV and 10 16 GeV, respectively.
The Turbulent Cascade and Proton Heating in the Solar Wind During Solar Minimum

The recently protracted solar minimum provided years of interplanetary data that were largely absent in any association with observed large-scale transient behavior on the Sun. With large-scale shear at 1 AU generally isolated to corotating interaction regions, it is reasonable to ask whether the solar wind is significantly turbulent at this time. We perform a series of third-moment analyses using data from the Advanced Composition Explorer. We show that the solar wind at 1 AU is just as turbulent as at any other time in the solar cycle. Specifically, the turbulent cascade of energy scales in the same manner proportional to the product of wind speed and temperature. Energy cascade rates during solar minimum average a factor of 2-4 higher than during solar maximum, but we contend that this is likely the result of having a different admixture of high-latitude sources.
Supersymmetry and Fredholm Modules Over Quantized Spaces

The purpose of this paper is to apply the framework of non-commutative differential geometry to quantum deformations of a class of Kahler manifolds. For the examples of the Cartan domains of type I and flat space, we construct Fredholm modules over the quantized manifolds using the supercharges which arise in the quantization of supersymmetric generalizations of the manifolds. We compute an explicit formula for the Chern character on generators of the Toeplitz ℂ*-algebra.
Understanding Child Outcomes: An Application to Child Abuse and Neglect

Recently, there have been several empirical studies exploring the effects of abortion on child outcome by correlating the availability of abortion to a mother at the time of a child's birth. This paper presents a model that helps explain the process, as well as establish that the incidence of child neglect is also reduced by access to abortion. It argues that the birth of a child reduces the desired quality of not only that particular birth but of all previous and subsequent offspring. More specifically, a family does not reduce the quality invested in a particular child, whether unwanted or not, but in all family members. Several propositions derived from the model are empirically tested. Some of the findings include that access to abortion reduces the neglect of children, yet is positively associated with sexual abuse. Furthermore, unlike the stylized facts, blacks and female-headed households are no more likely to neglect and abuse their children than other households once availability of abortion, employment status, income and other variables are taken into account. Finally, income and the poverty rate are found to be unrelated with maltreatment, while other variables such as the unemployment rate have better explanatory power.
Pilot modeling and closed-loop analysis of flexible aircraft in the pitch tracking task

The issue addressed in the appropriate modeling technique for pilot vehicle analysis of large flexible aircraft, when the frequency separation between the rigid-body mode and the dynamic aeroelastic modes is reduced. This situation was shown to have significant effects on pitch-tracking performance and subjective rating of the task, obtained via fixed base simulation. Further, the dynamics in these cases are not well modeled with a rigid-body-like model obtained by including only 'static elastic' effects, for example. It is shown that pilot/vehicle analysis of this data supports the hypothesis that an appropriate pilot-model structure is an optimal-control pilot model of full order. This is in contrast to the contention that a representative model is of reduced order when the subject is controlling high-order dynamics as in a flexible vehicle. The key appears to be in the correct assessment of the pilot's objective of attempting to control 'rigid-body' vehicle response, a response that must be estimated by the pilot from observations contaminated by aeroelastic dynamics. Finally, a model-based metric is shown to correlate well with the pilot's subjective ratings.
Alkenenitriles: conjugate additions of alkyl iodides with a silica-supported zinc-copper matrix in water.

A new silica-supported zinc-copper matrix reagent promotes the conjugate addition of alkyl iodides to cyclic and acyclic alkenenitriles in water. X-ray diffraction and electron microscopy techniques suggest that the active copper species generated from elemental zinc and copper(I) iodide is finely dispersed, zerovalent copper. Alkyl iodides react with the silica-supported reagent to generate putative radicaloid intermediates that efficiently add to alkenenitriles to provide β-substituted nitriles. Conjugate additions to acyclic and cyclic 5−7-membered alkenenitriles are most effective for primary alkyliodides, although secondary and tertiary alkyliodides are viable reaction partners. The strategy addresses the challenge of performing conjugate additions to disubstituted alkenenitriles and demonstrates the beneficial role of the silica-supported reagent.
NEUTRON STARS AND BLACK HOLES AS MACHOs

We consider the contribution of neutron stars and black holes to the dynamical mass of galactic halos. In particular, we show that if these compact objects were produced by an early generation of stars with initial metallicity 10-4 Z☉, they can contribute at most 30%-40% of the Galactic halo mass without creating supersolar levels of enrichment. We show that the case for halo neutron stars and black holes cannot be rejected on metal overproduction arguments alone because of the critical factor of the choice of progenitor metallicity in determining the yields. We show that this scenario satisfies observational constraints, similar to but no more severe than those faced by halo white dwarfs. We also discuss the recent results on halo microlensing, the presence of enriched hot gas in clusters and groups of galaxies, and other observations. If there are halo neutron stars and black holes, they will be detected in the future as longer timescale events by microlensing experiments.
ON SOLVABLE SUBGROUPS OF AUTOMORPHISM GROUPS OF RIGHT-ANGLED ARTIN GROUPS

For any right-angled Artin group, we show that its outer automorphism group contains either a finite-index nilpotent subgroup or a nonabelian free subgroup. This is a weak Tits alternative theorem. We find a criterion on the defining graph that determines which case holds. We also consider some examples of solvable subgroups, including one that is not virtually nilpotent and is embedded in a non-obvious way.
INNER-TRUNCATED DISKS IN GALAXIES

We present an analysis of the disk brightness profiles of 218 spiral and lenticular galaxies. At least 28% of disk galaxies exhibit inner truncations in these profiles. There are no significant trends of truncation incidence with Hubble type, but the incidence among barred systems is 49%, more than 4 times that for nonbarred galaxies. However, not all barred systems have inner truncations, and not all inner-truncated systems are currently barred. Truncations represent a real dearth of disk stars in the inner regions and are not an artifact of our selection or fitting procedures nor the result of obscuration by dust. Disk surface brightness profiles in the outer regions are well represented by simple exponentials for both truncated and nontruncated disks. However, truncated and nontruncated systems have systematically different slopes and central surface brightness parameters for their disk brightness distributions. Truncation radii do not appear to correlate well with the sizes or brightnesses of the bulges. This suggests that the low angular momentum material apparently missing from the inner disk was not simply consumed in forming the bulge population. Disk parameters and the statistics of bar orientations in our sample indicate that the missing stars of the inner disk have not simply been redistributed azimuthally into bar structures. The sharpness of the brightness truncations and their locations with respect to other galactic structures suggest that resonances associated with disk kinematics, or tidal interactions with the mass of bulge stars, might be responsible for this phenomenon.
An Introduction to Active Galactic Nuclei

How can we test if a supermassive black hole lies at the heart of every active galactic nucleus? What are LINERS, BL Lacs, N galaxies, broad-line radio galaxies and radio-quiet quasars and how do they compare? This timely textbook answers these questions in a clear, comprehensive and self-contained introduction to active galactic nuclei - for graduate students in astronomy and physics. The study of AGN is one of the most dynamic areas of contemporary astronomy, involving one fifth of all research astronomers. This textbook provides a systematic review of the observed properties of AGN across the entire electromagnetic spectrum, examines the underlying physics, and shows how the brightest AGN, quasars, can be used to probe the farthest reaches of the Universe. This book serves as both an entry point to the research literature and as a valuable reference for researchers in the field.
Facile Synthesis of Aluminum‐Containing Mixed‐Metal Oxides Using Doped Carboxylate Alumoxane Nanoparticles

A simple and rapid process has been developed that allows the formation of highly crystalline main-group, lanthanide, and transition-metal aluminates, including CaAl 12 O 19 (hibonite), Y 3 Al 5 O 12 (yttrium aluminum garnet, YAG), LaAl 11 O 18 LaAlO 3 , Ce 2 Al 3 O 8 , NdAlO 3 , Er 6 Al 10 O 24 , and Al 2 TiO 5 . Carboxylate-stabilized alumina nanoparticles (carboxylate alumoxanes) are reacted with the appropriate metal acetylacetonate complexes to form metal-doped carboxylate alumoxanes and aluminum acetylacetonate via a facile transmetalation reaction. Thermolysis of the metal-doped carboxylate alumoxanes, up to a temperature of 1400°C, yields crystalline aluminates, as confirmed by X-ray diffractometry, electron microprobe analysis, and scanning electron microscopy. The synthesis of different phases (i.e., LaAl 11 O 18 versus LaAlO 3 ) is controlled by the stoichiometry of the transmetalation reaction. A new, distorted, perovskite phase (with lattice parameters of a = 5.47 A and c = 13.3 A) of LaAlO 3 is formed. The alumoxane methodology results in multicomponent aluminate materials that are obtained in shorter processing times and with greater phase purity than previously reported. This observation is undoubtedly due to the atomic-scale mixing that is inherent in the alumoxane nanoparticle approach.
Collision avoidance interface for safe piloting of unmanned vehicles using a mobile device

Autonomous robots and vehicles can perform tasks that are unsafe or undesirable for humans to do themselves, such as investigate safety in nuclear reactors or assess structural damage to a building or bridge after an earthquake. In addition, improvements in autonomous modes of such vehicles are making it easier for minimally-trained individuals to operate the vehicles. As the autonomous capabilities advance, the user's role shifts from a direct teleoperator to a supervisory control role. Since the human operator is often better suited to make decisions in uncertain situations, it is important for the human operator to have awareness of the environment in which the vehicle is operating in order to prevent collisions and damage to the vehicle as well as the structures and people in the vicinity. In this paper, we present the Collision and Obstacle Detection and Alerting (CODA) display, a novel interface to enable safe piloting of a Micro Aerial Vehicle with a mobile device in real-world settings.
A Bayesian analysis of tree structure specification in nested logit models

Abstract This paper adopts a Bayesian approach to the problem of tree structure specification in nested logit models. I use the Laplace approximation and Reversible Jump Markov Chain Monte Carlo (RJMCMC) to estimate marginal likelihoods in both a simulated and a travel mode choice data set. I find that the Laplace approximation is remarkably accurate, and that model selection is invariant to prior specification.
A Homologation Approach to the Synthesis of Difluorinated Cycloalkynes

Difluorinated cyclooctynes are important reagents for labeling azido-biomolecules through copper-free click chemistry. Here, a safe, scalable synthesis of a difluorinated cyclooctyne is reported, which involves a key homologation/ring-expansion reaction. Sequential ring expansions were also employed to synthesize and study a novel difluorinated cyclononyne.
Discovery of a Wide Binary Brown Dwarf Born in Isolation

During a survey for stars with disks in the Taurus star-forming region using the Spitzer Space Telescope, we have discovered a pair of young brown dwarfs, FU Tau A and B, in the Barnard 215 dark cloud. They have a projected angular separation of 57, corresponding to 800 AU at the distance of Taurus. To assess the nature of these two objects, we have obtained spectra of them and constructed spectral energy distributions. Both sources are young (~1 Myr) according to their Hα emission, gravity-sensitive spectral features, and mid-infrared excess emission. The proper motion of FU Tau A provides additional evidence of its membership in Taurus. We measure spectral types of M7.25 and M9.25 for FU Tau A and B, respectively, which correspond to masses of ~0.05 and ~0.015 M ☉ according to the evolutionary models of Chabrier and Baraffe. FU Tau A is significantly overluminous relative to an isochrone passing through FU Tau B and relative to other members of Taurus near its spectral type, which may indicate that it is an unresolved binary. FU Tau A and B are likely to be components of a binary system based on the low probability (~3 × 10–4) that Taurus would produce two unrelated brown dwarfs with a projected separation of a ≤ 6''. Barnard 215 contains only one other young star and is in a remote area of Taurus, making FU Tau A and B the first spectroscopically confirmed brown dwarfs discovered forming in isolation rather than in a stellar cluster or aggregate. Because they were born in isolation and comprise a weakly bound binary, dynamical interactions with stars could not have played a role in their formation, and thus are not essential for the birth of brown dwarfs.
Using contingent valuation to explore willingness to pay for renewable energy: A comparison of collective and voluntary payment vehicles

Abstract This study uses a split-sample, dichotomous choice contingent valuation survey of 1574 U.S. residents to explore willingness to pay (WTP) for renewable energy under collective and voluntary payment vehicles, and under government and private provision of the good. We also evaluate the impact of “participation expectations” on stated WTP. We find some evidence that, when confronted with a collective payment mechanism, respondents state a somewhat higher WTP than when voluntary payment mechanisms are used. Similarly, private provision of the good elicits a somewhat higher WTP than does government provision. We also find that contingent valuation responses are strongly correlated with expectations for the WTP of others. Our results shed light on strategic response behavior and the incentive compatibility of different CV designs, and offer practical insight into U.S. household preferences for how to support renewable energy.
John Archibald Wheeler: A Few Highlights of His Contributions to Physics

The following quotations describe in “nutshells” a few highlights of John Archibald Wheeler’s contributions to physics. The contributions are arranged in roughly the following order: (i) concrete research results, (ii) innovative ideas that have become foundations for the research of others, (iii) insights that give guidance for the development of physics over the coming decades. Since most of Wheeler’s work contains strong elements of two or even all three of these characteristics, the editors have not attempted to delineate the dividing lines between the three categories.
Exploring the connections among job accessibility, employment, income, and auto ownership using structural equation modeling

Using structural equation modeling, this study empirically examines the connections between job accessibility, workers per capita, income per capita, and autos per capita at the aggregate level with year 2000 census tract data in Sacramento County, CA. Under the specification of the conceptual model, the model implied covariance matrix exhibits a reasonably good fit to the observed covariance matrix. The direct and total effects are largely consistent with theory and/or with empirical observations across a variety of geographic contexts. It is demonstrated that structural equation modeling is a powerful tool for capturing the endogeneity among job accessibility, employment, income, and auto ownership.
Do people really support trade restrictions? Cross-country evidence

We investigate the effect of trade restrictions on the perception of well-being. Using combined cross-sectional micro data from the World Values Survey and the European Values Survey of individuals in 89 countries, we find that citizens of a country with a lower degree of trade restrictions are more satisfied with their lives. The results are also robust across different measures of well-being, different definitions of trade restrictions, different estimation methods, and different sample sizes.
On the Secular Behavior of Irregular Satellites

Although analytical studies on the secular motion of the irregular satellites have been published recently, these theories have not yet been satisfactorily reconciled with the results of direct numerical integrations. These discrepancies occur because in secular theories the disturbing function is generally averaged over the Sun's orbital motion, whereas instead one should take into account some periodic terms, most notably the so-called evection, which can be large for distant, slow-moving satellites. This problem is identical to that initially encountered by Newton and other historical researchers when studying the Moon's motion. Here we demonstrate that the evection and other terms from lunar theory can be incorporated into the more modern Kozai formalism and that our synthetic approach produces much better agreement with results from symplectic integrations. Using this method, we plot the locations of secular resonances in the orbital-element space inhabited by the irregular satellites. Our model is found to predict correctly those satellites that are resonant or near-resonant. We also analyze the octupole term in the disturbing function to determine the strengths of resonant locking for satellites whose longitudes of pericenter are librating. By independently integrating these satellites' nominal orbits using a symplectic integrator, we show that the strength of this resonance can be successfully obtained from simple analytical arguments. We note that the distribution of irregular satellite clusters in the space of proper orbital elements appears to be nonrandom. We find that the large majority of irregular-satellite groups cluster close to the secular resonances, with several objects (Pasiphae, Sinope, Siarnaq, formerly S/2000 S3, and Stephano, formerly S/1999 U2) having practically stationary pericenters. After proposing the name main sequence to describe this grouping, we point out that none of the largest satellites (those with radii R > 100 km) belong to this class. Finally, we argue that this dichotomy implies that the smaller near-resonant satellites might have been captured differently than the largest irregulars.
State-Switched Absorber for Vibration Control of Point-Excited Beams:

A system that has the capability to make instantaneous changes in its mass, stiffness, or damping may be termed a state-switchable dynamical system. Such a system will display different dynamical responses dependent upon its current state. State-switchable stiffness may be practically obtained through the control of the termination impedance of piezoelectric stiffness elements. If such a switchable stiffness element is incorporated as part of the spring element of a vibration absorber, the change in stiffness causes a change in the resonance frequencies of the system, thereby instantaneously 'retuning' the state-switched absorber to a new frequency. In between state switches, the operation of such a device is passive, being fundamentally a passive vibration absorber. This concept has improved performance over classical passive vibration absorbers or dampers, particularly for disturbances with multiple spectral components. This paper considers the application of such a device for the purpose of vibration control on beams subjected to harmonic point-force excitation.