cssi/SciSciGPT-SciSciNet huggingface dataset:
Images of eigenvalue distributions under power maps

In [9], it was shown that if U is a random n×n unitary matrix, then for any p≥n, the eigenvalues of U p are i.i.d. uniform; similar results were also shown for general compact Lie groups. We study what happens when p<n instead. For the classical groups, we find that we can describe the eigenvalue distribution of U p in terms of the eigenvalue distributions of smaller classical groups; the earlier result is then a special case. The proofs rely on the fact that a certain subgroup of the Weyl group is itself a Weyl group. We generalize this fact, and use it to study the power-map problem for general compact Lie groups.
Extragalactic Radio Sources and the WMAP Cold Spot

We detect a dip of 20%-45% in the surface brightness and number counts of NRAO VLA Sky Survey (NVSS) sources smoothed to a few degrees at the location of the WMAP cold spot. The dip has structure on scales of ~1° to 10°. Together with independent all-sky wavelet analyses, our results suggest that the dip in extragalactic brightness and number counts and the WMAP cold spot are physically related, i.e., that the coincidence is neither a statistical anomaly nor a WMAP foreground-correction problem. If the cold spot does originate from structures at modest redshifts, as we suggest, then there is no remaining need for non-Gaussian processes at the last scattering surface of the cosmic microwave background (CMB) to explain the cold spot. The late integrated Sachs-Wolfe effect, already seen statistically for NVSS source counts, can now be seen to operate on a single region. To create the magnitude and angular size of the WMAP cold spot requires a ~140 Mpc radius completely empty void at z ≤ 1 along this line of sight. This is far outside the current expectations of the concordance cosmology, and adds to the anomalies seen in the CMB.
Another heteroskedasticity- and autocorrelation-consistent covariance matrix estimator

Abstract A ✓T- consistent estimator of a heteroskedasticity and autocorrelation consistent covariance matrix estimator is proposed and evaluated. The relevant applications are ones in which the regression disturbance follows a moving average process of known order. In a system of l equations, this ‘AM-l’ estimator entails estimation of the moving average coefficients of an l-dimensional vector. Simulations indicate that the MA-l estimator's finite sample performance is better than that of the estimators of Andrews and Monahan (1992) and Newey and West (1994) when cross-products of instruments and disturbances are sharply negatively autocorrelated, comparable or slightly worse otherwise.
Time-reversal symmetry, Poincaré recurrence, irreversibility, and the entropic arrow of time: From mechanics to system thermodynamics

In this paper, we use a large-scale dynamical systems perspective to provide a system-theoretic foundation for thermodynamics. Specifically, using a state space formulation, we develop a nonlinear compartmental dynamical system model characterized by energy conservation laws that is consistent with basic thermodynamic principles. In addition, we establish the existence of a unique, continuously differentiable global entropy function for our large-scale dynamical system, and using Lyapunov stability theory we show that the proposed thermodynamic model has convergent trajectories to Lyapunov stable equilibria determined by the system initial energies. Finally, using the system entropy, we establish the absence of Poincare recurrence for our thermodynamic model and develop a clear connection between irreversibility, the second law of thermodynamics, and the entropic arrow of time.
The connection between the narrow-line region and the uv absorbers in seyfert galaxies

We present evidence that the outflowing UV absorbers in Seyfert 1 galaxies arise primarily in their inner narrow- (emission-) line regions (NLRs), based on similarities in their locations, kinematics, and physical conditions. Hubble Space Telescope observations show that nearly all Seyfert galaxies have bright, central knots of [O III] emission in their NLRs with radii of tens of parsecs. These sizes are consistent with most previous estimates of the distances of UV (and X-ray) absorbers from their central continuum sources and a recently obtained reliable distance of ~25 pc for a UV absorber in the Seyfert 1 galaxy NGC 3783. The nuclear emission-line knots in a sample of 10 Seyfert galaxies have velocity widths of 300-1100 km s-1 (half-width at zero intensity), similar to the radial velocities of most UV absorbers. The highest radial velocity for a Seyfert UV absorber to date is only -2100 km s-1, which is much lower than typical broad-line region (BLR) velocities. There is also mounting evidence that the NLR clouds are outflowing from the nucleus, like the UV absorbers. If our hypothesis is correct, then the NLR should have a component with a high global covering factor (Cg) of the continuum source and a BLR to match that found from previous surveys of UV absorbers (Cg = 0.5-1.0). Using Space Telescope Imaging Spectrograph spectra of NGC 4151, obtained when the continuum and BLR fluxes were low, we find evidence for optically thin gas in its nuclear emission-line knot. We are able to match the line ratios from this gas with photoionization models that include a component with Cg ≈ 1 and an ionization parameter and hydrogen column density that are typical of UV absorbers.
K23Au12Sn9—An Intermetallic Compound Containing a Large Gold−Tin Cluster: Synthesis, Structure, and Bonding

A polyanionic unit {Au12Sn9} with a novel “corrugated sheet” shape occurs in K23Au12Sn9. The compound was obtained by fusion of the pure elements in tantalum ampules at high temperatures followed by programmed cooling, and the structure was determined by X-ray diffraction: I42m (No. 121), a = 20.834(3), c = 6.818(1) A, Z = 2. The large heteroatomic cluster has D2d point symmetry and features a central four bonded (4b-) Sn, eight 3b- or 2b-Sn on the perimeter, and 24 linking nearly linear Sn−Au bonds at 12 Au atoms. Formula splitting according to the Zintl concept suggests that the compound is one electron deficient, and linear muffin-tin-orbital (LMTO) electronic structure calculations show that the Fermi level (EF) lies near a band gap at around 0.5 eV, that is, an incompletely filled valence band in concert with favorable atom packing. Large relative −ICOHP values for Au−Sn are consistent with the observed maximization of the number of heteroatomic bonds, whereas the numerous K-Sn and K-Au contacts con...
Doppler optical coherence microscopy for studies of cochlear mechanics.

The possibility of measuring subnanometer motions with micron scale spatial resolution in the intact mammalian cochlea using Doppler optical coherence microscopy (DOCM) is demonstrated. A novel DOCM system is described that uses two acousto-optic modulators to generate a stable 500-kHz heterodyne frequency. Images and motion measurements are obtained using phase-resolved analysis of the interference signal. The DOCM system permits imaging with micron-scale resolution and 85-dB sensitivity and motion measurements with 100-kHz bandwidth, directional discrimination, and 30-pm/Hz0.5 noise floor. Images and motion measurements are presented that demonstrate the ability to resolve motions of structures of interest in a mammalian cochlea in vitro including the basilar membrane, reticular lamina, tectorial membrane, and outer hair cells.
Bis(trimethylsilyl) enol ethers as 1,3-dianion equivalents: Regiocontrolled [3+4] and [3+5] annulation reactions

Abstract In the presence of titanium tetrachloride, 1,3-bis(trimethylsiloxy)-1-methoxy-1,3-butadiene (1) undergoes facile [3 + n] annulation reactions with 1,4- and 1,5-dielectrophiles to generate seven- and eight-membered bicyclic ether adducts. The annulations occur in good yields (49–83%) and are also highly regioselective for substrates containing two distinct electrophilic groups.
BIS(dioxothiacyclopenta)-tetrathiafulvalene

Abstract A novel synthesis and some physical properties of bis(dioxothia-cyclopenta)-tetrathiafulvalene (7), a new π-electron donor, are reported.
The Neber Route to Substituted Indoles

Two complementary procedures have been developed for the conversion of the oximes of α-aryl ketones to azirines. On heating, the azirines rearrange smoothly to the corresponding indoles. The overall transformation offers a versatile route to indoles, complementary to the Fischer indole synthesis.
BIRD'S-EYE VIEW OF GnRH ANALOG USE IN A PEDIATRIC ENDOCRINOLOGY REFERRAL CENTER

ABSTRACT Objective: Gonadotropin-releasing hormone analogs (GnRHa) are standard of care for the treatment of central precocious puberty (CPP). GnRHa have also been prescribed in other clinical settings with the hope of increasing adult stature, although evidence to support this practice is lacking. The degree to which GnRHa are being prescribed for indications other than CPP in routine clinical care has not been described. We sought to systematically examine GnRHa prescribing practices among the pediatric endocrinologists at our academic medical center. Methods: We reviewed medical records of children treated with GnRHa during a 6-year interval. Variables analyzed included gender, age at start of treatment, indication for therapy, and use of growth hormone as adjunctive treatment. Nonparametric analyses were utilized to compare treatment characteristics of those with CPP versus those without. Results: A total of 260 patients (82% female) aged 8.06 ± 2.68 years were identified. Of these, 191 (73.5%) were t...
Simulation of Quantum Adiabatic Search in the Presence of Noise

Results are presented of a large-scale simulation of the quantum adiabatic search (QuAdS) algorithm in the presence of noise. The algorithm is applied to the NP-Complete problem N-Bit Exact Cover 3 (EC3). The noise is assumed to Zeeman-couple to the qubits and its effects on the algorithm's performance is studied for various levels of noise power, and for four different types of noise polarization. We examine the scaling relation between the number of bits N (EC3 problem-size) and the algorithm's noise-averaged median run-time 〈T(N)〉. Clear evidence is found of the algorithm's sensitivity to noise. Two fits to the simulation results were done: (i) power-law scaling 〈T(N)〉 = aNb; and (ii) exponential scaling 〈T(N)〉 = a[exp(bN) - 1]. Both types of scaling relations provided excellent fits, although the scaling parameters a and b varied with noise power, and with the type of noise polarization. The sensitivity of the scaling exponent b to noise polarization allows a relative assessment of which noise polarizations are most problematic for quantum adiabatic search. We demonstrate how the noise leads to decoherence in QuAdS, and estimate the amount of decoherence present in our simulations. An upper bound is also derived for the noise-averaged QuAdS success probability in the limit of weak noise that is appropriate for our simulations.
Solitons on intersecting 3-Branes II: a holographic perspective

We study the low energy effective theory of two sets of D3-branes overlapping in 1+1 dimensions, recently considered by Mintun, Polchinski, and Sun. In the original treatment by MPS, by studying the properties of magnetic solitons, the low energy effective field theory was found to require some ultraviolet completion, possibly involving full string dynamics. Recently in a companion paper, it was shown that by scaling the angle between the D3-branes and the D3′-branes in the zero slope limit in specific way, one can find simpler effective field theory which consists of a single tower of Regge trajectory states and yet is ultraviolet complete and non-singular. In this article, we study this model by further studying a limit which recovers the MPS dynamics from this non-singular construction. We approach this issue from a holographic perspective, where we consider a stack of N D3-branes overlapping with a single D3′-brane, and treat that D3′-brane as a probe in the AdS5 × S 5 dual. In general, the D3′-brane probe supports a magnetic monopole as a non-singular soliton configuration, but in the limit where the MPS dynamics is recovered, the soliton degenerates. This is consistent with the idea that the effective dynamics in the MPS setup is incomplete, but that it can be completed with a single tower of Regge trajectory states.
Clues to galaxy activity from rich cluster simulations

New simulations of rich cluster evolution are used to evaluate the first infall hypothesis of Gunn and Dressler - the idea that the enhanced fraction of active galaxies seen in high redshift clusters is due to a one-time burst of star formation triggered by the rapid rise in external pressure as a galaxy plows into the hot intracluster medium (ICM). Using three-dimensional simulations which contain both baryonic gas and collisionless dark material, local static pressure histories for test orbits of galaxies are generated and a simple trigger threshold based on dP/dt/P sub ISM is applied to define an active fraction of the population. The results lend qualitative and quantitative support to the first infall interpretation.
Samarium(II) Iodide-Mediated Reductive Annulations of Ketones Bearing a Distal Vinyl Epoxide Moiety

Samarium(II) iodide in the presence of hexamethylphosphoramide (HMPA) efficiently promotes the intramolecular coupling of ketones with distal epoxy olefins. The reaction appears to proceed by a mechanism wherein a ketyl couples with the unsaturated epoxide. Subsequent fragmentation of the epoxide ring in compounds 1a−k yields carbocycles 2a−k with an allyl alcohol side chain in good yields, and often with high diastereoselectivity. When tetramethylguanidine was used as an additive instead of HMPA, the desired carbocycle was obtained in good yield, but the diastereoselectivity was diminished. A palladium(0)-catalyzed SmI2 reaction provided the expected product in modest yield, but the sense of diastereoselectivity was reversed. In the latter case, a different reaction mechanism may be involved. Thus, formation of an allylsamarium species may be invoked, with nucleophilic carbonyl addition leading to the observed facial selectivity.
Vector Expected Utility and Attitudes Toward Variation

This paper proposes a model of decision under ambiguity deemed vector expected utility, or VEU. In this model, an uncertain prospect, or Savage act, is assessed according to (a) a baseline expected-utility evaluation ,a nd (b) anadjustment that reflects the individual’s perception of ambiguity and her attitudes toward it. The adjustment is itself a function of the act’s exposure to distinct sources of ambiguity, as well as its variability. The key elements of the VEU model are a baseline probability and a collection of random variables, or adjustment factors, which represent acts exposed to distinct ambiguity sources and also reflect complementarities among ambiguous events. The adjustment to the baseline expected-utility evaluation of an act is a function of the covariance of its utility profile with each adjustment factor, which reflects exposure to the corresponding ambiguity source. A behavioral characterization of the VEU model is provided. Furthermore, an updating rule for VEU preferences is proposed and characterized. The suggested updating rule facilitates the analysis of sophisticated dynamic choice with VEU preferences.
The synthesis and catalytic activity of the iridium(I) hydroquinone complex [(H2Q)Ir(COD)]+

Abstract The η6-hydroquinone iridium complex [(η6-H2Q)Ir(COD)]BF4 undergoes facile double deprotonation to the η4-quinone anionic analogue. The latter has been shown to be the first example of an iridium complex that catalyzes 1,4 conjugate addition reactions of aryl boronic acids to electron deficient olefins.
Pushing Requirements Changes through to Changes in Specifications

Requirements changes can occur both during and after a phase of development. It is difficult and intensive work to integrate requirements changes made after specification is completed. Sequence-based specification was developed to convert ordinary functional requirements into complete, consistent, and traceably correct specifications through a constructive process. Algorithms for managing requirements changes meet a very great need in field application of the sequence-based specification method. In this paper we propose to capture requirements changes as a series of atomic changes in specifications, and present algorithms for managing these changes. The algorithms are built into the tool support with which users are able to push requirements changes through to changes in specifications, maintain old specifications over time and evolve them into new specifications with the least amount of human interaction and rework. All our change algorithms are supported by rigorous mathematical formulation and proof of correctness.
The Aging Population and the Size of the Welfare State: Is There a Puzzle?

Abstract Razin, Sadka, and Swagel [Razin, Asaf, Efraim Sadka, and Phillip Swagel (2002) “The Aging Population and the Size of the Welfare State” The Journal of Political Economy, vol. 110, no. 4, pp. 900–918.] unveil a puzzling fact: the welfare state appears to be shrinking even as the dependency ratio rises. While they formulate an elegant political economy model to explain the coexistence of an aging population and declining transfers, the resolution of the puzzle turns out to be much simpler. Labor tax rates and per capita transfers are negatively correlated with the dependency ratio in advanced economies only because this measure includes children as well as retirees. Both labor tax rates and per capita transfers in advanced economies are, in fact, historically positively correlated with the ratio of retirees to the working-age population and negatively correlated with the ratio of children to the working-age population. Increasing the number of retirees shifts preferences toward higher taxes and transfers by increasing the fraction of the population that receives transfers. In contrast, workers with more children prefer to spend more of their lifetime income while raising dependents, so they prefer smaller public pension systems. These results suggest that fiscal leakage from workers to retirees is not required to explain the broad trends in the transfer policies of advanced economies.
The Minimum Description Length Principle

The minimum description length (MDL) principle is a powerful method of inductive inference, the basis of statistical modeling, pattern recognition, and machine learning. It holds that the best explanation, given a limited set of observed data, is the one that permits the greatest compression of the data. MDL methods are particularly well-suited for dealing with model selection, prediction, and estimation problems in situations where the models under consideration can be arbitrarily complex, and overfitting the data is a serious concern.This extensive, step-by-step introduction to the MDL Principle provides a comprehensive reference (with an emphasis on conceptual issues) that is accessible to graduate students and researchers in statistics, pattern classification, machine learning, and data mining, to philosophers interested in the foundations of statistics, and to researchers in other applied sciences that involve model selection, including biology, econometrics, and experimental psychology. Part I provides a basic introduction to MDL and an overview of the concepts in statistics and information theory needed to understand MDL. Part II treats universal coding, the information-theoretic notion on which MDL is built, and part III gives a formal treatment of MDL theory as a theory of inductive inference based on universal coding. Part IV provides a comprehensive overview of the statistical theory of exponential families with an emphasis on their information-theoretic properties. The text includes a number of summaries, paragraphs offering the reader a "fast track" through the material, and boxes highlighting the most important concepts.
Effective interactions for light nuclei: an effective (field theory) approach

One of the central open problems in nuclear physics is the construction of effective interactions suitable for many-body calculations. We discuss a recently developed approach to this problem, where one starts with an effective field theory containing only fermion fields and formulated directly in a no-core shell-model space. We present applications to light nuclei and to systems of a few atoms in a harmonic-oscillator trap. Future applications and extensions, as well as challenges, are also considered.
Hardness and microstructure of internally oxidized silver alloys

Alloys of Ag, Ag/1.12 at.% Mg, and Ag/0.25 at.% Mg-0.25 at.%Ni were internally oxidized at 450 to 825/spl deg/C and their hardnesses and microstructures were observed. Microhardness profiles showed that hardness was high near the surface and decreased with depth into the sample. Microstructures contained regions of small and large grains, where region sizes were dependent on treatment temperature. Transitions between small- and large-grained regions were abrupt. Treatments at higher temperatures failed to alter grain structure, indicating that Mg-O clusters had indeed pinned the grain boundaries. Clustering was shown to affect the hardness of oxidized alloys, not only by inhibiting grain growth, but also by inhibiting dislocation motion.
A Density—Quantile Function Perspective on Robust Estimation

Publisher Summary This chapter presents a perspective on robust estimation by regarding it as one of the components of a unified theory of statistical science, in which various approaches are applied simultaneously, such as parametric statistical inference, goodness of fit procedures, robust statistical inference, exploratory data analysis, and non-parametric statistical inference. A key to accomplishing such unification might be to think in terms of quantile functions and density-quantile functions. Parametric statistical inference may be concerned with statistical inference of parameters of a model from data assumed to satisfy the model. Goodness of fit procedures is concerned with testing whether a specified parametric model adequately fits the observed sample probabilities. Robust statistical inference may be concerned with statistical inference of parameters of a model from data assumed to satisfy the model only approximately. Exploratory data analysis may be concerned with statistical inference from data that is nonideal in the sense that it is not assumed to obey a specified model.
The Luminous Infrared Host Galaxy of Short-duration GRB 100206A

The known host galaxies of short-hard gamma-ray bursts (GRBs) to date are characterized by low to moderate star formation rates (SFRs) and a broad range of stellar masses, in general agreement with models associating the phenomenon with an old progenitor, such as merging neutron stars. In this paper, we positionally associate the recent unambiguously short-hard Swift GRB 100206A with a disk galaxy at redshift z = 0.4068 that is rapidly forming stars at a rate of 30 M ⊙yr-1, almost an order of magnitude higher than any previously identified short-GRB host. The galaxy is very red (g - K = 4.3ABmag), heavily obscured (AV 2mag), and has the highest metallicity of any GRB host to date (12 + log[O/H]KD02 = 9.2): it is a classical luminous infrared galaxy (LIRG), with L IR 4 × 1011 L ⊙. While these properties could be interpreted to support an association of this GRB with recent star formation, modeling of the broadband spectral energy distribution also indicates that a substantial stellar mass of mostly older stars is also present. The specific SFR is modest (sSFR 0.5Gyr-1), the current SFR is not substantially elevated above its long-term average, and the host morphology shows no sign of recent merger activity. Our observations are therefore equally consistent with an older progenitor. Given the precedent established by previous short-GRB hosts and the significant fraction of the universe's stellar mass in LIRG-like systems at z ≳ 0.3, an older progenitor represents the most likely origin of this event. © 2012. The American Astronomical Society. All rights reserved.
Modeling, control and power quality evaluation of a PEM fuel cell based power supply system for residential use

The use of fuel-cell (FC)-based power generation systems is expected to become more widespread in the near future due to better power quality, reliability, portability, and ecological constraints. The use of FC technology for electricity and heat generation for residential applications generated tremendous interest. Proton exchange membrane FCs (PEMFCs) are attractive for residential use due to its low operating temperature and fast startup characteristics. This paper focuses on the modeling, control (voltage and active power control), and simulation of PEMFC-based power supply system for residential applications. A proportional-integral (PI)-type voltage and real power controller is usually implemented by controlling the fuel input into FC stack and adjusting the inverter modulation index. Furthermore, power-quality issues are evaluated based on the transformer connection type and harmonic content of the load for household appliances. Detailed simulation software has been developed using the Matlab software package. The topology chosen for the simulation consists of a 5-kW PEMFC, a single-stage-voltage-sourced pulsewidth-modulation inverter followed by an LC filter and a step-up transformer. The simulation results illustrate that the voltage at the load point and active power demand versus load variations can be achieved using the PI controller. The control parameters used involves inverter modulation index and phase angle. The power-quality evaluation confirms that the bus voltage harmonics meet the IEEE-519 requirements for all home appliances, which are modeled based on real measured values. However, system voltage and current harmonics can be affected either by the harmonic contents of load current or supply voltage overlap at resonance frequency
Temporal synchronization in video watermarking

One of the challenges for blind watermark detection is synchronization. Synchronization is the process of identifying the coordinates of an embedded watermark and is crucial in successful watermark detection. If the detector's input is watermarked but synchronization fails, then the embedded watermark will not be detected. In this paper, temporal synchronization for blind video watermark detection is examined by developing new models for watermark embedding and detection. The structure of the watermark, and specifically its key schedule, dramatically affects the ease of synchronization. The new embedder models the construction of the watermark by using a state machine key generator. The key generator can produce time-invariant, time-independent, and time-periodic key schedules as special cases. The watermark detector uses a queue and a state predictor to perform a search to establish and maintain temporal synchronization. These models are general and can be applied to many symmetric blind video watermarking techniques. It is shown that a watermark without temporal redundancy in its key schedule is vulnerable to attacks such as frame dropping and transposition. Using the models, a watermark more resilient against temporal synchronization attacks is designed by adding temporal redundancy in the watermark construction. Experimental results from an implementation of the models are presented.
The Relationship of Self-Concept and Self-Care in Children with Cancer

The purposes of this descriptive study were to examine the relationships between self-concept and (a) self-care, (b) dependent-care, and (c) basic conditioning factors for children with cancer, and to compare the self-concept of children on- and off-therapy. The theoretical framework was Orem's self-care deficit theory of nursing. The sample consisted of 74 children with cancer and their mothers. Results showed small but significant correlations between variables, providing some evidence that if children had higher self-concept scores they performed more self-care activities and received more dependent-care from their mothers. The self-concept scores of the on- and off-therapy groups were not significantly different. This study supports Orem's theory and reinforces the need to promote positive self-concept.
“TO BE INDIFFERENT AND TO BE YOUNG”: DISRAELI, SYBIL , AND THE PRESERVATION OF AN AMERICAN “RACE,” 1879–1912

On November 16, 1918, a little more than two weeks after an armistice officially ended World War I, an editorial in the Idaho Statesman offered advice about the future of the world economy. Lifting the title of its editorial directly from Benjamin Disraeli's Sybil, or The Two Nations, the Statesman argued only the political philosophy espoused by that novel and its author could show the world a way forward. Quoting from the novel's final paragraph, the newspaper declares: “‘To be indifferent and to be young can no longer be synonymous.’ Those words were true when Disraeli penned them just 73 years ago, but they apply with striking force to the problems of today and to the problems which will be certain to develop in the years just ahead” (“Trustees of Posterity” 4). The newspaper wasn't only advocating political involvement by the nation's youth, nor was Disraeli. Sybil proposes a particular kind of economic and political order, a union between a “just” aristocracy, led by the young and ambitious, and the laboring classes. It proposes that great statesmen take up the mantle of responsibility just as Thomas Carlyle, in Disraeli's day, advocated great captains of industry take up that mantle (Houghton 328). The newspaper's argument implies this seventy-year-old British novel will be critical to America's political future. But this vision of responsibility belongs in the nineteenth century – it is rooted in the conflict between republicanism and aristocratic oligarchy – and the timing of the Statesman article at first seems wildly inappropriate. As the First World War ended, the Statesman expected the world would face the kind of threats Americans had perceived before the war. The editorial warns that “mobocracy” still “holds nearly half of the area of Europe and much of northern Asia in its bloody and irresponsible grip.” If there is any doubt about who is behind this “mobocracy,” the newspaper clears that matter up, answering: “Bolshevists, Socialists and all of the disciples of unrest who may be roughly grouped as ‘The Reds’” (“Trustees of Posterity” 4). And when the Statesmen warns about “Reds,” it can easily expect its readers to remember that, only seventeen years earlier, President McKinley had been shot by just such a “Red”: Leon Czolgosz, an alleged anarchist and the child of Polish immigrants.
Shock Losses in Transonic Compressor Blade Rows

The rather extensive study of the shock losses in transonic compressors can he summarized by the following remarks: 1. A simple flow model can be used to estimate shock losses at the design point for transonic compressor blade rows and results iii reasonable correlation of loss data. It is indicated that shock losses can constitute a sizable portion of the total losses in it transonic compressor rotor. This includes all blade elements at which sonic or higher relative velocities are obtained. 2. Shock losses can he shown to exist across the blade passage (free-stream loss) and by the method of superposition with the blade profile losses result in an estimated design total loss coefficient. 3. The shock configuration was experimentally determined by the rapid pressure rise between the blades as measured by the use of barium titanate crystals. At the minimum loss operating conditions the shock is very similar to that assumed in the simple How model. 4. Shock losses obtained from a more detailed flow model were compared with the losses obtained by the simple flow model. Measured loss distribution from blade to blade closely approaches the analytical shock loss distribution. The measured distribution shows the effect of a shock boundary layer interaction. 5. The analytical method (from the detailed flow model) of determining the shock location ahead of the blade seems to apply reasonably well over a range of incidence angles. The analytical shock losses do not vary a great deal with blade element incidence angles.
Embryonic pattern scaling achieved by oppositely directed morphogen gradients.

Morphogens are proteins, often produced in a localized region, whose concentrations spatially demarcate regions of differing gene expression in developing embryos. The boundaries of gene expression are typically sharp and the genes can be viewed as abruptly switching from on to off or vice versa upon crossing the boundary. To ensure the viability of the organism these boundaries must be set at certain fractional positions within the corresponding developing field. Remarkably this can be done with high precision despite the fact that the size of the developing field itself can vary widely from embryo to embryo. How this scaling is accomplished is unknown but it is clear that a single morphogen gradient is insufficient. Here we show how a pair of morphogens A and B, produced at opposite ends of a one-dimensional developing field, can solve the pattern-scaling problem. In the most promising scenario the morphogens interact via an effective annihilation reaction A + B → ∅ and the switch occurs according to the absolute concentration of A or B. We define a scaling criterion and show that morphogens coupled in this way can set embryonic markers across the entire developing field in proportion to the field size. This scaling occurs at developing-field sizes of a few times the morphogen decay length. The scaling criterion is not met if instead the gradients couple combinatorially such that downstream genes are regulated by the ratio A/B of the morphogen concentrations.
True Womanhood in Hollywood: Gendered Business Strategies and the Rise and Fall of the Woman Filmmaker, 1896–1928

Women flourished as producers, directors, screenwriters, and editors in the first quarter-century of the film industry. But by 1925 their presence in all but screenwriting was severely diminished. The argument of this essay is that the process of gendering the industry ultimately closed studio doors to female filmmakers. As studios moved from the artistic and entrepreneurial stage, conducive to the perceived qualities of women, to the corporate stage, the needs of the industry became masculinized and women were excluded. This process is explored by examining the assumptions regarding gender inherited by the early movie industry and the context in which gender was discussed within the industry, and by asking whether explicit assumptions about the fitness of women and men were ever factors in determining what and who a filmmaker should be.
A comparison of cardinal tournaments and piece rate contracts with liquidity constrained agents

A celebrated result in the theory of tournaments is that relative performance evaluation (tournaments) is a superior compensation method to absolute performance evaluation (piece rate contracts) when the agents are risk-averse, the principal is risk-neutral or less risk-averse than the agents and production is subject to common shocks that are large relative to the idiosyncratic shocks. This is because tournaments get closer to the first best by filtering common uncertainty. This paper shows that, surprisingly, tournaments are superior even when agents are liquidity constrained so that transfers to them cannot fall short of a predetermined level. The rationale is that, by providing insurance against common shocks through a tournament, payments to the agents in unfavorable states increase and payments in favorable states decrease which enables the principal to satisfy tight liquidity constraints for the agents without paying any ex ante rents to them, while simultaneously providing higher-power incentives than under piece rates. The policy implication of our analysis is that firms should adopt relative performance evaluation over absolute performance evaluation regardless of whether the agents are liquidity (wealth) constrained or not.
Equation of state of the alpha and epsilon phases of iron

Abstract An empirical equation of state that is thermodynamically consistent is found for the alpha (body-centered-cubic) and epsilon (hexagonal-close-packed) phases of iron. It is fit to all available types of experimental data-calorimetic, thermal expansion, acoustic, static compression, and shock data. All thermodynamic identities are satisfied, since expressions for all observables are derived from a thermodynamic potential. No specific theoretical assumptions are made, but the Helmholtz potential is formulated in terms of a number of adjustable functions of single variables by applying some general considerations of lattice vibrations, conduction electrons, and ferromagnetic exchange interaction. The effective Gruneisen parameter depends on temperature as well as volume. Ultrasonic and shock data for the alpha phase are found to be consistent with X-ray determinations of compression based on the sodium chloride standard. The Slater and Dugdale-MacDonald relations are tested against the fit at low pressure and are found to be in error. At high pressure not enough different types of data exist to establish a unique fit without theoretical assumptions.
Remote timing attacks are practical

Timing attacks are usually used to attack weak computing devices such as smartcards. We show that timing attacks apply to general software systems. Specifically, we devise a timing attack against OpenSSL. Our experiments show that we can extract private keys from an OpenSSL-based web server running on a machine in the local network. Our results demonstrate that timing attacks against network servers are practical and therefore security systems should defend against them.
Creation of new lasing modes with spatially nonuniform gain

We report on the creation of new lasing modes with spatially nonuniform profiles of optical gain in a one-dimensional random structure. It is demonstrated numerically that even without gain saturation and mode competition, the spatial nonuniformity of gain can cause dramatic and complicated changes. New lasing modes appear with frequencies between those of the lasing modes with uniform gain. We examine new modes in detail and find that they exhibit high output directionality. Our results show that random lasing properties may be modified significantly without changing the underlying structure.
HOW MANY SMALL FIRMS ARE ENOUGH

Individual investors are undiversified, holding on average less than four securities in their personal portfolios. The small firm literature focuses on CAPM (systematic risk, full diversification concept) premia, and the actual performance of small firm portfolios held by investors is overstated because of the presence of unsystematic risk. This paper illustrates the magnitudes of total risk for small and large firms, and the behavior of such measures as portfolio size is altered. Small firms contain more risk as shown by the finding that a diversified portfolio of small firms has greater variability than a single, typical large firm. While small firms outperform large firms, investors should be aware of the implications for small firm undiversified portfolios. Because small firms contain large amounts of unsystematic risk, diversification is important if investors are going to capture the small firm premia reported in the literature.
A MODEL OF OVERCONFIDENCE

People use information about their ability to choose tasks. If more challenging tasks provide more accurate information about ability, people who care about and who are risk averse over their perception of their ability will choose tasks that are not sufficiently challenging. Moderate overestimation of ability and overestimation of the precision of initial information leads people to choose tasks that raise expected output (and utility); however, extreme overconfidence leads people to undertake tasks that are excessively challenging. Consistent with our results, psychologists find that moderate overconfidence is both pervasive and advantageous.
Controlled Crystallization of the Amorphous Phase in Silicon Nitride Ceramics

The controlled crystallization of amorphous second phases in SiAlON is demonstrated in two systems. In a magnesia-containing SiAlON, cordierite crystallized on annealing after hot-pressing. Similarly, garnet crystallized in yttria-contain-ing SiAlON. The resulting microstructures are characterized by TEM and qualitatively related to changes on room-temperature toughness and high-temperature deformation.
Viscous Properties of Strongly Interacting Matter at High Temperature

Substantial collective flow is observed in collisions between large nuclei at high energy, and the data are well-reproduced by perfect fluid dynamics. In a separate development, calculation of the dimensionless ratio of shear viscosity $\eta$ to entropy density within AdS/CFT yields $\eta/s = 1/4\pi$, which has been conjectured to be a lower bound for any physical system. It is shown that the transition from hadrons to quarks and gluons has behavior similar to helium, nitrogen, and water at and near their phase transitions in the ratio $\eta/s$. Conversely, there are indications that the ratio of bulk viscosity $\zeta$ to entropy density may have a maximum in the vicinity of the phase transition. Therefore it is possible that experimental measurements can pinpoint the location of the transition or rapid crossover in QCD via the ratios $\eta/s$ and $\zeta/s$ in addition to and independently of the equation of state.
ROBUSTNESS OF NON-PARAMETRIC MEASUREMENT OF EFFICIENCY AND RISK AVERSION

This paper examines the performance of a risk-adjusted non-parametric approach to measuring efficiency and risk aversion. Prior work is extended to the case where agent behavior is motivated by expected utility maximization. Results indicate the approach significantly outperforms traditional efficiency measurement methods when applied to risk averse agents.
Evaporation of ice in planetary atmospheres: Ice-covered rivers on mars

Abstract The evaporation rate of water ice on the surface of a planet with an atmosphere involves an equilibrium between solar heating and radiative and evaporative cooling of the ice layer. The thickness of the ice is governed principally by the solar flux which penetrates the ice layer and then is conducted back to the surface. These calculations differ from those of Lingenfelter et al. [(1968) Science 161, 266–269] for putative lunar channels in including the effect of the atmosphere. Evaporation from the surface is governed by two physical phenomena: wind and free convection. In the former case, water vapor diffuses from the surface of the ice through a lamonar boundary layer and then is carried away by eddy diffusion above, provided by the wind. The latter case, in the absence of wind, is similar, except that the eddy diffusion is caused by the lower density of water vapor than the Martian atmosphere. For mean Martian insolations the evaporation rate above the ice is ∼ 10−8 g cm−2 sec−1. Thus, even under present Martian conditions a flowing channel of liquid water will be covered with ice which evaporates sufficiently slowly that the water below can flow for hundreds of kilometers even with quite modest discharges. Evaporation rates are calculated for a wide range of frictional velocities, atmospheric pressures, and insolations and it seems clear that at least some subset of observed Martian channels may have formed as ice-choked rivers. Typical equilibrium thicknesses of such ice covers are ∼ 10 to 30 m; typical surface temperatures are 210 to 235°K. Ice-covered channels or lakes on Mars today may be of substantial biological interest. Ice is a sufficiently poor conductor of heat that sunlight which penetrates it can cause melting to a depth of several meters or more. Because the obliquity of Mars can vary up to some 35°, the increased polar heating at such times seems able to cause subsurface melting of the ice caps to a depth which corresponds to the observed lamina thickness and may be responsible for the morphology of these polar features.
A Model of Reference-Dependent Preferences

We develop a model of reference-dependent preferences and loss aversion where “gain‐loss utility” is derived from standard “consumption utility” and the reference point is determined endogenously by the economic environment. We assume that a person’s reference point is her rational expectations held in the recent past about outcomes, which are determined in a personal equilibrium by the requirement that they must be consistent with optimal behavior given expectations. In deterministic environments, choices maximize consumption utility, but gain‐loss utility influences behavior when there is uncertainty. Applying the model to consumer behavior, we show that willingness to pay for a good is increasing in the expected probability of purchase and in the expected prices conditional on purchase. In within-day labor-supply decisions, a worker is less likely to continue work if income earned thus far is unexpectedly high, but more likely to show up as well as continue work if expected income is high.
Pressure Measurements in the Exhaust of a Pulsed Megawatt MPD Arc Thruster

Pulsed megawatt MPD arc thruster exhaust pressure measurements, discussing time dependence, peak dynamic and static pressures, etc
Greenhouse Gas Emission Impacts of Carsharing in North America

This paper evaluates the greenhouse gas (GHG) emission impacts that result from individuals participating in carsharing organizations within North America. The authors con ducted an online survey with members of major carsharing organizations and evaluated the change in annual household emissions (e.g., impact) of respondents that joined carsharing. The results show that a majority of households joining carsharing are increasing their emissions by gaining access to automobiles. However, individually, these increases are small. In contrast, the remaining households are decreasing their emissions by shedding vehicles and driving less. The collective emission reductions outweigh the collective emission increases, which implies that carsharing reduces GHG emissions as a whole. The results are reported in the form of an observed impact, which strictly evaluates the changes in emissions that physically occur, and a full impact, which also considers emissions that would have happened but were avoided due to carsharing. The mean observed impact is -0.58 t GHG/year per household, whereas the mean full impact is -0.84 t GHG/year per household. Both means are statistically significant. We present a sensitivity analysis to evaluate the robustness of the results and find that the overall results hold across a variety of assumptions. The average observed vehicle kilometers traveled (VKT) per year was found to decline by 27%. We conclude with an evaluation of the annual aggregate impacts of carsharing based on current knowledge of the industry membership population.
Dynamic Late Merge-Control Concept for Work Zones on Rural Interstate Highways

Conventional traffic control plans for lane closures of rural Interstate highways normally work well as long as congestion does not develop. However, when the traffic demand exceeds the capacity of the work zone, queues may extend back past the advance warning signs, often surprising approaching traffic and increasing the accident potential. Also, smooth and orderly merging operations may be lost as some drivers remain in the closed lane attempting to squeeze into the open lane at the head of the queue, while other drivers try to prevent drivers in the closed lane from passing them by straddling the centerline or traveling slowly in tandem with another vehicle in the closed lane. These maneuvers tend to reduce the capacity of the merging operation and increase the accident potential and road rage among drivers. Early merge and late merge are two forms of merge control designed to deal with these problems. However, these approaches have operational characteristics that limit their effectiveness under both ...