cssi/SciSciGPT-SciSciNet huggingface dataset:
Exploiting high pressures to generate porosity, polymorphism, and lattice expansion in the nonporous molecular framework Zn(CN)2.

Systematic exploration of the molecular framework material Zn(CN)2 at high pressure has revealed several distinct series of transitions leading to five new phases: four crystalline and one amorphous. The structures of the new crystalline phases have been resolved through ab initio structural determination, combining charge flipping and direct space methods, based on synchrotron powder diffraction data. The specific transition activated under pressure depends principally on the pressure-transmitting fluid used. Without fluid or in large molecule fluids (e.g., isopropanol, ethanol, or fluorinert), the high-pressure behavior intrinsic to Zn(CN)2 is observed; the doubly interpenetrated diamondoid framework structure transforms to a distorted, orthorhombic polymorph, Zn(CN)2-II (Pbca) at ∼1.50–1.58 GPa with asymmetric displacement of the bridging CN ligand and reorientation of the Zn(C/N)4 tetrahedra. In small molecule fluids (e.g., water, methanol, methanol–ethanol–water), the nonporous interpenetrated Zn(CN)...
“Last-Place Aversion”: Evidence and Redistributive Implications

We present evidence from laboratory experiments showing that individuals are ‘‘last-place averse.’’ Participants choose gambles with the potential to move them out of last place that they reject when randomly placed in other parts of the distribution. In modified dictator games, participants randomly placed in second-to-last place are the most likely to give money to the person one rank above them instead of the person one rank below. Last-place aversion suggests that low-income individuals might oppose redistribution because it could differentially help the group just beneath them. Using survey data, we show that individuals making just above the minimum wage are the most likely to oppose its increase. Similarly, in the General Social Survey, those above poverty but below median income support redistribution significantly less than their background characteristics would predict. JEL Codes: H23, D31, C91.
Lagrangian Coherent Structures near a Subtropical Jet Stream

Direct Lyapunov exponents and stability results are used to extract and distinguish Lagrangian coherent structures (LCS) from a three-dimensional atmospheric dataset generated from the Weather Research and Forecasting (WRF) model. The numerical model is centered at 19.788N, 155.558W, initialized from the Global Forecast System for the case of a subtropical jet stream near Hawaii on 12 December 2002. The LCS are identified that appear to create optical and mechanical turbulence, as evidenced by balloon data collected during a measurement campaign near Hawaii.
Pinching estimates for negatively curved manifolds with nilpotent fundamental groups

Let M be a complete Riemannian metric of sectional curvature within [−a2,−1] whose fundamental group contains a k-step nilpotent subgroup of finite index. We prove that a ≥ k answering a question of M. Gromov. Furthermore, we show that for any \(\epsilon > 0,\) the manifold M admits a complete Riemannian metric of sectional curvature within \([ - (k + \epsilon )^2 , - 1].\)
Instability of sharing systems in the presence of retransmissions

Retransmissions represent a primary failure recovery mechanism on all layers of communication network architecture. Similarly, fair sharing, for example, processor sharing (PS), is a widely accepted approach to resource allocation among multiple users. Recent work has shown that retransmissions in failure-prone, for example, wireless ad hoc, networks can cause heavy tails and long delays. In this paper, we discover a new phenomenon showing that PS-based scheduling induces complete instability with zero throughput in the presence of retransmissions, regardless of how low the traffic load may be. This phenomenon occurs even when the job sizes are bounded/fragmented, for example, deterministic. Our analytical results are further validated via simulation experiments. Moreover, our work demonstrates that scheduling one job at a time, such as first-come-first-serve, achieves a larger stability region and should be preferred in these systems.
The Age of the Universe and the Cosmological Constant Determined from Cosmic Microwave Background Anisotropy Measurements

If Ωtot = 1 and structure formed from adiabatic initial conditions, then the age of the universe, as constrained by measurements of the cosmic microwave background (CMB), is t0 = 14.0 ± 0.5 Gyr. The uncertainty is surprisingly small given that CMB data alone do not significantly constrain either h or ΩΛ. This small uncertainty is due to the tight (and accidental) correlation in flat adiabatic models of the age with the angle subtended by the sound horizon on the last-scattering surface and, thus, with the well-determined acoustic peak locations. If we assume either the Hubble Space Telescope Key Project result h = 0.72 ± 0.08 or simply that h > 0.55, we find ΩΛ > 0.4 at 95% confidence—another argument for dark energy, independent of supernovae observations. Our analysis is greatly simplified by the Monte Carlo Markov chain approach to Bayesian inference combined with a fast method for calculating angular power spectra.
Sampler placement to determine emission factors from ground level area sources

Emission factors are used by state air pollution regulatory agencies to regulate emissions from sources of atmospheric pollution. Emission factors for ground level area sources (GLASs) can be determined by sampling ambient pollutant levels and using dispersion modeling to back-calculate the emission rate from a source. This manuscript describes a method used to locate samplers downwind of a GLAS to most accurately determine the emission flux from the source. Contributions from other sources, changes in particle size distributions, and measurement uncertainty are considered.
Testing Hardy–Weinberg equilibrium with a simple root-mean-square statistic

SUMMARY We provide evidence that, in certain circumstances, a root-mean-square test of goodness of fit can be significantly more powerful than state-of-the-art tests in detecting deviations from Hardy–Weinberg equilibrium. Unlike Pearson’s χ 2 test, the log-likelihood-ratio test, and Fisher’s exact test, which are sensitive to relative discrepancies between genotypic frequencies, the root-mean-square test is sensitive to absolute discrepancies. This can increase statistical power, as we demonstrate using benchmark data sets and simulations, and through asymptotic analysis.
On time-scale designs for networks

We motivate the problem of designing a subset of the edge weights in a graph, to shape the spectrum of an associated linear time-invariant dynamics. We address a canonical design problem of this form by applying time-scale assignment methods, and give graph-theoretic characterisations of the designed dynamics.
Reformulating the situation calculus and the event calculus in the general theory of stable models and in answer set programming

Circumscription and logic programs under the stable model semantics are two wellknown nonmonotonic formalisms. The former has served as a basis of classical logic based action formalisms, such as the situation calculus, the event calculus and temporal action logics; the latter has served as a basis of a family of action languages, such as language A and several of its descendants. Based on the discovery that circumscription and the stable model semantics coincide on a class of canonical formulas, we reformulate the situation calculus and the event calculus in the general theory of stable models. We also present a translation that turns the reformulations further into answer set programs, so that efficient answer set solvers can be applied to compute the situation calculus and the event calculus.
Rotor Wake Variability in a Multistage Compressor

Rotorwakevariability isnot typically accountedforin computational fluid dynamics models,yet small deviations from the modeled average wake could have impacts on performance and forced vibratory response of airfoils. This paper quantifies rotor wake variability, in terms of wake depth and width, for each stage in a three-stage research compressor. Time-resolved flow angle data are acquired with a cross-film sensor at midspan for all three rotor exits for 50 circumferential positions spanning a vane passage. This research focuses on rotor wake variability driven by blade row interactions. The scope of the study includes wake variations caused by blade-to-blade differences, interactions with upstream rotor wakes, and interactions with the potential field of the downstream vane row. The lowest levels of variability are associated with rotor 1. In the downstream rotors, ensemble-averaged revolutions of data show an amplitude modulation caused by interactions with the rotor wakes from the upstream blade rows and, thus, increased levels of blade-to-blade wake variability. The main effect of the downstream vane row is to shift the mean levels of the wake without significantly influencing the wake shape. Nomenclature mc = corrected mass flow rate Nc = corrected rotational speed R = rotor Rec = Reynolds number based on chord length S = stator t = time U = wheel speed V = flow velocity in the absolute reference frame W = flow velocity in the rotating reference frame � = absolute flow angle � = relative flow angle � = adiabatic efficiency � = standard deviation
A computational model for the stereoscopic optics of a head-mounted display

For stereoscopic photography or telepresence, orthostereoscopy occurs when the perceived size, shape, and relative position of objects in the three-dimensional scene being viewed match those of the physical objects in front of the camera. In virtual reality, the simulated scene has no physical counterpart, so orthostereoscopy must be defined in this case as constancy, as the head moves around, of the perceived size, shape, and relative positions of the simulated objects. Achieving this constancy requires that the computational model used to generate the graphics matches the physical geometry of the head-mounted display being used. This geometry includes the optics used to image the displays and the placement of the displays with respect to the eyes. The model may fail to match the geometry because model parameters are difficult to measure accurately, or because the model itself is in error. Two common modeling errors are ignoring the distortion caused by the optics and ignoring the variation in interpupillary distance across different users. A computational model for the geometry of a head-mounted display is presented, and the parameters of this model for the VPL EyePhone are calculated.
The influence of thermal-hydraulic-mechanical- and chemical effects on the evolution of permeability, seismicity and heat production in geothermal reservoirs

a b s t r a c t A coupled continuum model representing thermo-hydro-mechanical behaviors is applied to follow the evolution of induced seismicity within a prototypical enhanced geothermal system (EGS) reservoir. The model is applied to the potential Newberry EGS field (USA) by assuming fracture sizes of 10-1200 m. Models are classified by their conceptualization of the fractured reservoir geometry as networks of dis- crete fractures and with equivalent fractured media as fill-in. The THMC model is applied to a doublet injector-producer to explore the spatial and temporal triggering of seismicity for varied fracture network geometries both shallow (2000 m) and at depth (2750 m). The magnitude of the resulting seismic events is in the range −2 to +1.9. The largest event size (∼1.9) corresponds to the largest fracture size (∼1200 m) within the reservoir. The rate of hydraulic and thermal transport has a considerable influence on the amount, location, and timing of failure, and ultimately, on the event rate. The event rate is highest when the fracture density is highest (0.9 m−1) and the initial stresses highest (at depth). In all cases, the a-value decreases and the b-value increases with time. The b-value is largest (∼1.34) for the highest fracture density and the highest stress regime. Thermal energy recovered during production is also greatest at depth and for the highest density of fractures.
Glycans as receptors for influenza pathogenesis

Influenza A viruses, members of the Orthomyxoviridae family, are responsible for annual seasonal influenza epidemics and occasional global pandemics. The binding of viral coat glycoprotein hemagglutinin (HA) to sialylated glycan receptors on host epithelial cells is the critical initial step in the infection and transmission of these viruses. Scientists believe that a switch in the binding specificity of HA from Neu5Acα2-3Gal linked (α2-3) to Neu5Acα2-6Gal linked (α2-6) glycans is essential for the crossover of the viruses from avian to human hosts. However, studies have shown that the classification of glycan binding preference of HA based on sialic acid linkage alone is insufficient to establish a correlation between receptor specificity of HA and the efficient transmission of influenza A viruses. A recent study reported extensive diversity in the structure and composition of α2-6 glycans (which goes beyond the sialic acid linkage) in human upper respiratory epithelia and identified different glycan structural topologies. Biochemical examination of the multivalent HA binding to these diverse sialylated glycan structures also demonstrated that high affinity binding of HA to α2-6 glycans with a characteristic umbrella-like structural topology is critical for efficient human adaptation and human-human transmission of influenza A viruses. This review summarizes studies which suggest a new paradigm for understanding the role of the structure of sialylated glycan receptors in influenza virus pathogenesis.
Tree of Life Reveals Clock-Like Speciation and Diversification

Genomic data are rapidly resolving the tree of living species calibrated to time, the timetree of life, which will provide a framework for research in diverse fields of science. Previous analyses of taxonomically restricted timetrees have found a decline in the rate of diversification in many groups of organisms, often attributed to ecological interactions among species. Here, we have synthesized a global timetree of life from 2,274 studies representing 50,632 species and examined the pattern and rate of diversification as well as the timing of speciation. We found that species diversity has been mostly expanding overall and in many smaller groups of species, and that the rate of diversification in eukaryotes has been mostly constant. We also identified, and avoided, potential biases that may have influenced previous analyses of diversification including low levels of taxon sampling, small clade size, and the inclusion of stem branches in clade analyses. We found consistency in time-to-speciation among plants and animals, ∼2 My, as measured by intervals of crown and stem species times. Together, this clock-like change at different levels suggests that speciation and diversification are processes dominated by random events and that adaptive change is largely a separate process.
ON THE TOPOLOGY OF ENDING LAMINATION SPACE

We show that if S is a nite type orientable surface of genus g and p punctures where 3g + p 5, thenEL(S) is (n 1)-connected and (n 1)- locally connected, where dim(PML(S)) = 2n + 1 = 6g + 2p 7. Furthermore, if g = 0, thenEL(S) is homeomorphic to the p 4 dimensional Nobeling space.
The effect of aging on the utilization of chemotherapy for metastatic breast cancer: a population-based study.

Older women (i. e., ≤65 years of age) receive less adjuvant chemotherapy than younger women, in part because chemotherapy has been less effective in postmenopausal than premenopausal women in Clinical Trials. Metastatic breast cancer, however, does not respond differently to chemotherapy by age. Therefore, to evaluate further the effect of age on chemotherapy utilization, we conducted a population-based study of the treatment of metastatic breast cancer. Patients (n = 132) were identified by cross-tabulating death certificates from 1984 to 1991 with breast cancer cases in the Washington County Cancer Registry. Treatment information was obtained from the Tumor Registry of the Washington County Hospital and Hospital medical records. Forty patients (74%) <65 years old received chemotherapy compared to 11 (42%) 65-74 and 6 (12%) ≤75 (p < 0.0001). Adjusting for other medical conditions and whether or not the patient saw a medical oncologist, there was still a significant effect of age in patients ≤75 (p < 0.00...
Stereo vision for planetary rovers: stochastic modeling to near real-time implementation

NASA scenarios for lunar and planetary missions include robotic vehicles that function in both teleoperated and semi-autonomous modes. Under teleoperation, on-board stereo cameras may provide 3-D scene information to human operators via stereographic displays; likewise, under semi-autonomy, machine stereo vision may provide 3-D information for obstacle avoidance. In the past, the slow speed of machine stereo vision systems has posed a hurdle to the semi-autonomous scenario; however, recent work at JPL and other laboratories has produced stereo systems with high reliability and near real-time performance for low-resolution image pairs. In particular, JPL has taken a significant step by achieving the first autonomous, cross-country robotic traverses (of up to 100 meters) to use stereo vision, with all computing on-board the vehicle. Here, we describe the stereo vision system, including the underlying statistical model and the details of the implementation. The statistical and algorithmic aspects employ random field models of the disparity map, Bayesian formulations of single-scale matching, and area-based image comparisons. The implementation builds bandpass image pyramids and produces disparity maps from the 60×64 level of the pyramids at rates of up to two seconds per image pair. All vision processing is done in one 68020 augmented with Datacube image processing boards. We argue that the overall approach provides a unifying paradigm for practical, domain-independent stereo ranging. We close with a discussion of practical and theoretical issues involved in evaluating and extending the performance of the stereo system.
Design of Lipid Nanocapsule Delivery Vehicles for Multivalent Display of Recombinant Env Trimers in HIV Vaccination

Immunization strategies that elicit antibodies capable of neutralizing diverse virus strains will likely be an important part of a successful vaccine against HIV. However, strategies to promote robust humoral responses against the native intact HIV envelope trimer structure are lacking. We recently developed chemically cross-linked lipid nanocapsules as carriers of molecular adjuvants and encapsulated or surface-displayed antigens, which promoted follicular helper T-cell responses and elicited high-avidity, durable antibody responses to a candidate malaria antigen. To apply this system to the delivery of HIV antigens, Env gp140 trimers with terminal his-tags (gp140T-his) were anchored to the surface of lipid nanocapsules via Ni-NTA-functionalized lipids. Initial experiments revealed that the large (409 kDa), heavily glycosylated trimers were capable of extracting fluid phase lipids from the membranes of nanocapsules. Thus, liquid-ordered and/or gel-phase lipid compositions were required to stably anchor trimers to the particle membranes. Trimer-loaded nanocapsules combined with the clinically relevant adjuvant monophosphoryl lipid A primed high-titer antibody responses in mice at antigen doses ranging from 5 μg to as low as 100 ng, whereas titers dropped more than 50-fold over the same dose range when soluble trimer was mixed with a strong oil-in-water adjuvant comparator. Nanocapsule immunization also broadened the number of distinct epitopes on the HIV trimer recognized by the antibody response. These results suggest that nanocapsules displaying HIV trimers in an oriented, multivalent presentation can promote key aspects of the humoral response against Env immunogens.
Ambiguity, Information Quality, and Asset Pricing

When ambiguity-averse investors process news of uncertain quality, they act as if they take a worst-case assessment of quality. As a result, they react more strongly to bad news than to good news. They also dislike assets for which information quality is poor, especially when the underlying fundamentals are volatile. These effects induce ambiguity premia that depend on idiosyncratic risk in fundamentals as well as skewness in returns. Moreover, shocks to information quality can have persistent negative effects on prices even if fundamentals do not change. FINANCIAL MARKET PARTICIPANTS ABSORB a large amount of news, or signals, every day. Processing a signal involves quality judgments: News from a reliable source should lead to more portfolio rebalancing than news from an obscure source. Unfortunately, judging quality itself is sometimes difficult. For example, stock picks from an unknown newsletter without a track record might be very reliable or entirely useless—it is simply hard to tell. Of course, the situation is different when investors can draw on a lot of experience that helps them interpret signals. This is true especially for “tangible” information, such as earnings reports, that lends itself to quantitative analysis. By looking at past data, investors may become quite confident about how well earnings forecast returns. This paper focuses on information processing when there is incomplete knowledge about signal quality. The main idea is that, when quality is difficult to judge, investors treat signals as ambiguous. They do not update beliefs in standard Bayesian fashion, but behave as if they have multiple likelihoods in mind when processing signals. To be concrete, suppose that θ is a parameter that an investor wants to learn. We assume that a signal s is related to the parameter by a family of likelihoods: s = θ + � , � ∼ N � 0, σ 2 s � , σ 2 s ∈ � σ 2
A Model-Independent Determination of the Expansion and Acceleration Rates of the Universe as a Function of Redshift and Constraints on Dark Energy

Determination of the expansion and acceleration history of the universe is one of the fundamental goals of cosmology. Detailed measurements of these rates as a function of redshift can provide new physical insights into the nature and evolution of the dark energy, which apparently dominates the global dynamics of the universe at the present epoch. We present here dimensionless coordinate distances y(z) to 20 radio galaxies reaching out to z ≈ 1.8, the redshift range currently not covered by supernova standard-candle observations. There is very good agreement between coordinate distances to radio galaxies and supernovae for the redshift range in which these measurements overlap, suggesting that neither is plagued at this level by unknown systematic errors. We develop a simple numerical method for a direct determination of the expansion and acceleration rates, E(z) and q(z), from the data, which makes no assumptions about the underlying cosmological model or the equation of state parameter w. This differential method is in contrast to the traditional cosmological tests, in which particular model equations are integrated and then compared with the observations. The new approach is model independent, but at a cost of being noisier and highly sensitive to the amount and quality of the available data. We illustrate the method by applying it to the currently available supernova data and the data on radio galaxies presented here. We derive the expansion rate of the universe as a function of redshift, E(z), and for the first time we obtain a direct estimate of the acceleration rate of the universe as a function of redshift, q(z), in a way that is independent of assumptions regarding the dark energy and its redshift evolution. The current observations indicate that the universe makes a transition from acceleration to deceleration at a redshift greater than 0.3, with a best-fit estimate of about 0.45; this transition redshift and our determinations of E(z) are broadly in agreement with the currently popular Friedmann-Lemaitre cosmology with Ωm = 0.3 and ΩΛ = 0.7, even though no model assumptions are made in deriving the fits for E(z) and q(z). With the advent of much better and richer data sets in the future, our direct method can provide a useful complementarity and an independent check on the traditional cosmological tests.
An Empirical Test of the Rent-Shifting Hypothesis: The Case of State Trading Enterprises

Abstract A central result in the theoretical literature on strategic trade is the ‘rent-shifting hypothesis’, the idea that government’s can employ trade policy as a precommitment device to transfer profit from foreign to domestic firms. To our knowledge, however, the rent-shifting hypothesis remains untested empirically. This paper constructs a theory-based empirical test of rent-shifting behavior that relies on observations of government precommitment variables employed through State Trading Enterprises (STEs). The analysis applies data on the delayed producer payment structure of the Canadian Wheat Board (CWB) and examines its merits as a rent-shifting mechanism in the international durum market. The model fails to reject the hypothesis that the CWB utilizes a pre-commitment mechanism in the international durum market and several nonparametric tests confirm that the observed transfer payments set by the CWB are consistent with rent-shifting behavior in the 1972–95 pre-WTO period.
Stochastic Relativistic Shock-surfing Acceleration

We study relativistic particles undergoing surfing acceleration at perpendicular shocks. We assume that particles undergo diffusion in the component of momentum perpendicular to the shock plane as a result of moderate fluctuations in the shock electric and magnetic fields. We show that dN/dE, the number of surfing-accelerated particles per unit energy, attains a power-law form, dN/dE E-b. We calculate b analytically in the limit of weak momentum diffusion, and use Monte Carlo test-particle calculations to evaluate b in the weak, moderate, and strong momentum-diffusion limits.
Mixed mode I/II fracture and fatigue crack growth along 63Sn–37Pb solder/brass interface

Abstract Solder joints are extensively used in electronic packaging. They provide critical electrical and mechanical connections. Single edge notched sandwich specimens, which were made of two blocks of brass joined with a 63Sn–37Pb solder layer, were prepared for a fatigue and fracture study of the joint under mixed mode loading. Mode I and mixed mode I/II fracture toughness, fatigue crack thresholds, and fatigue crack growth rates (FCGR) were measured at room temperature using a four point bending test setup. It was found that the fracture toughness of the joint increased and FCGR decreased upon the introduction of the mode II component. The interface fracture toughness was higher than that reported for pure solder. The data of FCGR correlated well with the power law relation of d a/ d N=C ∗ (ΔG) m , where ΔG is the alternating energy released rate for a crack under mixed mode loading. It was also observed that both fracture toughness and FCGR were a function of the solder layer thickness. When the solder layer thickness increased from 0.1 to 1.0 mm, the fracture toughness decreased substantially and FCGR increased slightly. For mode I loading, fatigue cracks propagated inside the solder layer. However, for mixed mode loading, once a crack initiated, it changed its direction toward the interface and then propagated along the interface. These observations were related to local mode I and mode II stress fields. Fracture surfaces showed signs of rubbing under mixed mode loading with elongated cavities at the crack tip. However, under mode I loading, fracture surfaces were covered with equi-ax voids.
Valuing a spatially variable environmental resource: reducing non-point source pollution in Green Bay, WI.

This article investigates the value of reducing non-point-source pollution in Green Bay, Wisconsin. Using stated preference methods, we find the lower bound on the benefits of reducing runoff enough to universally increase water clarity by 4 ft is greater than $10 million annually. Using a unique survey design, we show that because current water clarity in Green Bay is spatially variable, the value that a household places on this universal improvement depends on the distance of the household's residence from the bay and on the particular geospatial location of the residence. This has important implications for estimating aggregate benefits.
Multi-perspective video analysis of persons and vehicles for enhanced situational awareness

This paper presents a multi-perspective vision-based analysis of people and vehicle activities for the enhancement of situational awareness. Multiple perspectives provide a useful invariant feature of object in image, i.e., the footage area on the ground. Moving objects are detected in image domain, and tracking results of the objects are represented in projection domain using planar homography. Spatio-temporal relationships between human and vehicle tracks are categorized to safe or unsafe situation depending on site context such as walkway and driveway locations. Semantic-level information of the situation is achieved with the anticipation of possible directions of near-future tracks using piecewise velocity history. Crowd density is estimated from the footage in homography plane. Experimental data show promising results. Our framework can be applied to broad range of situational awareness for emergency response, disaster prevention, human interactions in structured environments, and crowd movement analysis in wide-view areas.
More on the narrowing of impact broadened radio recombination lines at high principal quantum number

Recently Alexander and Gulyaev have suggested that the apparent decrease in impact broadening of radio recombination lines seen at high principal quantum number n may be a product of the data reduction process, possibly resulting from the presence of noise on the telescope spectra that is not present on the calculated comparison spectra. This is an interesting proposal. However, there are serious problems with their analysis that need to be pointed out. Perhaps the most important of these is the fact that for principal quantum numbers below n=200, where the widths are not in question, their processed generated profile widths do not fit the widths of the processed lines obtained at the telescope. After processing, the halfwidths of the generated and telescope profiles must agree below n=200 if we are to believe that the processed generated linewidths above n=200 are meaningful. Theirs do not. Furthermore, we find that after applying the linewidth reduction factors found by Alexander and Gulyaev for their noise added profiles to our generated profiles to simulate their noise adding effect, the processed widths we obtain still do not come close to explaining the narrowing seen in the telescope lines for n values in the range 200<n<250. It is concluded that what is needed to solve this mystery is a completely new approach using a different observing technique instead of simply a further manipulation of the frequency-switched data.
Efficient detection and signal parameter estimation with applications to high dynamic GPS receivers

The author presents a technique for simultaneously detecting data and estimating the parameters of a receiver carrier signal phase that is modulated by unknown data and experiencing very high Doppler, Doppler rate, etc. Such a situation arises, for example, in the case of the Global Positioning System (GPS), where the signal parameters are directly related to the position, velocity, and acceleration of the GPS receiver. The proposed scheme is based upon first estimating the received signal local (data-dependent) parameters over two consecutive bit periods, followed by detecting a possible jump in these parameters. The presence of the detected jump signifies a data transition which is then removed from the received signal. This effectively demodulated signal is then processed to provide the estimates of global (data-independent) parameters of the signal related to the position, velocity, etc. of the receiver. >
The Thermodynamic Arrow-of-time and Quantum Mechanics

I give an explanation of the thermodynamic arrow-of-time (namely entropy increases with time) within a quantum mechanical framework. This entails giving a solution to the Loschmidt paradox, i.e. showing how an irreversible macro-dynamics can arise from a reversible micro-dynamics. I argue that, in accordance to the reversible dynamics, both entropy-increasing and entropy-decreasing transformations take place, but entropy-decreasing transformations cannot leave any information of their having happened. This is indistinguishable from their not having happened at all. The second law of thermodynamics is then reduced to a tautology: the only transformations that can be seen are those where entropy does not decrease. However, typicality arguments seem to prevent this argument to be used as a complete solution to the arrow-of-time dilemma: it might still be necessary to postulate a low entropy initial state for the system under consideration.
Earnings surprises that motivate analysts to reduce average forecast error

Large earnings surprises and negative earnings surprises represent more egregious errors in analysts' earnings forecasts. We find evidence consistent with our expectation that egregious forecast errors motivate analysts to work harder to develop or acquire relatively more private information in an effort to avoid future forecasting failures. Specifically, we find that after large or negative earnings surprises there is a greater reduction in the error in individual analysts' forecasts of future earnings, and these individual forecasts are based more heavily on individual analysts' private information. This increased reliance on private information reduces the error in the mean forecast of upcoming earnings (even after controlling for the effect of reduced error in individual forecasts). As reliance on private information increases, more of each individual forecast error is idiosyncratic, and thus averaged out in the computation of the mean forecast.
Auditing in the Presence of Outside Sources of Information

We examine how an auditor’s ability to terminate a multi-period client relationship provides the auditor with a real option whose value depends on the nature of informational asymmetry between the incumbent and other potential auditors. In particular, we isolate conditions under which the auditor’s private and public sources of information behave as complements rather than substitutes. In such circumstances, increasing the likelihood of publicly provided information induces the auditor to expend more (rather than less)resources in private information gathering activities.
Towards quantifying non-local information transfer: finite-bit non-locality

Abstract The advent of Bell's inequalities provoked the possibility that entangled quantum phenomena are non-local in nature. Since teleportation only requires two bits, we investigated whether non-local correlations can be further quantified in terms of finite information. The EPR–Bell cosine correlation is reproduced exactly using on average 1.48 bits.
Adaptive detector arrays for optical communications receivers

An optimal adaptive array receiver for use in groundbased optical communications is investigated. Kolmogorov phase screen simulations are used to generate realistic focal-plane distributions of the received optical fields in the presence of turbulence. The array detection concept reduces interference from background radiation by effectively assigning higher confidence levels at each instant of time to those detector elements that contain significant signal energy and suppressing those that do not. A simpler suboptimum structure that replaces the continuous weighting of the optimal receiver by a hard decision over each detector element is also described. It is shown that, for photon counting receivers observing Poisson distributed signals, performance improvements of up to 5 dB can be obtained over conventional single-detector photon counting receivers when observing turbulent optical fields in high background environments.
Interfaces between Molecular and Polymeric “Metals”: Electrically Conductive, Structure‐Enforced Assemblies of Metallomacrocycles

The design, synthesis, characterization, and understanding of new molecular and macro-molecular substances with “metal-like” electrical properties represents an active research area at the interface of chemistry, physics, and materials science. An important, long-range goal in this field of “materials by design” is to construct supermolecular assemblies which exhibit preordained collective phenomena by virtue of “engineered” interactions between molecular building blocks. In this review, such a class of designed materials is discussed which, in addition, bridges the gap between molecular and polymeric conductors: assemblies of electrically conductive metallomacrocycles. It is seen that efforts to rationally construct stacked metal-like molecular arrays lead logically to structure-enforced macromolecular assemblies of covalently linked molecular subunits. Typical building blocks are robust, chemically versatile metallophthalocyanines. The electrical optical, and magnetic properties of these metallomacrocyclic assemblies and the fragments thereof, provide fundamental information on the connections between local atomic-scale architecture, electronic structure, and the macroscopic collective properties of the bulk solid.
PRECISE RADIUS ESTIMATES FOR THE EXOPLANETS WASP-1b AND WASP-2b

We present precise z-band photometric time series spanning times of transit of the two exoplanets recently discovered by the SuperWASP collaboration. We find planetary radii of 1:44 � 0:08 and 1:04 � 0:06 RJ for WASP-1b and WASP-2b, respectively. These error estimates include both random errors in the photometry and also the uncertainty in the stellar masses. Our results are 5 times more precise than the values derived from the discovery data alone. Our measurement of the radius of WASP-2b agrees with previously published models of hot Jupiters that
On the robustness of aerosol effects on an idealized supercell storm simulated with a cloud system-resolving model

Abstract. A cloud system-resolving model (the Weather Research and Forecasting model) with 1 km horizontal grid spacing is used to investigate the response of an idealized supercell storm to increased cloud droplet concentrations associated with polluted conditions. The primary focus is on exploring robustness of simulated aerosol effects in the face of complex process interactions and feedbacks between the cloud microphysics and dynamics. Simulations are run using sixteen different model configurations with various microphysical or thermodynamic processes modified or turned off. Robustness of the storm response to polluted conditions is also explored for each configuration by performing additional simulations with small perturbations to the initial conditions. Differences in the domain-mean accumulated surface precipitation and convective mass flux between polluted and pristine conditions are small for almost all model configurations, with relative differences in each quantity generally less than 15%. Configurations that produce a decrease (increase) in cold pool strength in polluted conditions also tend to simulate a decrease (increase) in surface precipitation and convective mass flux. Combined with an analysis of the dynamical and thermodynamic fields, these results indicate the importance of interactions between microphysics, cold pool evolution, and dynamics along outflow boundaries in explaining the system response. Several model configurations, including the baseline, produce an overall similar storm response (weakening) in polluted conditions despite having different microphysical or thermodynamic processes turned off. With hail initiation turned off or the hail fallspeed-size relation set to that of snow, the model produces an invigoration instead of weakening of the storm in polluted conditions. These results highlight the difficulty of foreseeing impacts of changes to model parameterizations and isolating process interactions that drive the system response to aerosols. Overall, these findings are robust, in a qualitative sense, to small perturbations in the initial conditions. However, there is sensitivity in the magnitude, and in some cases sign, of the storm response to polluted conditions with small perturbations in the temperature of the thermal used to initiate convection (less than p0.5 K) or the vertical shear of the environmental wind (p5%). It is concluded that reducing uncertainty in simulations of aerosol effects on individual deep convective storms will likely require ensemble methods in addition to continued improvement of model parameterizations.
Target space duality I: General theory

Abstract We develop a systematic framework for studying target space duality at the classical level. We show that target space duality between manifolds M and M arises because of the existence of a very special symplectic manifold. This manifold locally looks like M× M and admits a double fibration. We analyze the local geometric requirements necessary for target space duality and prove that both manifolds must admit flat orthogonal connections. We show how abelian duality, nonabelian duality and Poisson–Lie duality are all special cases of a more general framework. As an example we exhibit new (nonlinear) dualities in the case M= M = R n .
On the structure of simplicial categories associated to quasi-categories

The homotopy coherent nerve from simplicial categories to simplicial sets and its left adjoint C are important to the study of (∞,1)-categories because they provide a means for comparing two models of their respective homotopy theories, giving a Quillen equivalence between the model structures for quasi-categories and simplicial categories. The functor C also gives a cofibrant replacement for ordinary categories, regarded as trivial simplicial categories. However, the hom-spaces of the simplicial category CX arising from a quasi-category X are not well understood. We show that when X is a quasi-category, all � 2 horns in the hom-spaces of its simplicial category can be filled. We prove, unexpectedly, that for any simplicial set X, the hom-spaces of CX are 3-coskeletal. We characterize the quasi-categories whose simplicial categories are locally quasi, finding explicit examples of 3-dimensional horns that cannot be filled in all other cases. Finally, we show that when X is the nerve of an ordinary category, CX is isomorphic to the simplicial category obtained from the standard free simplicial resolution, showing that the two known cofibrant “simplicial thickenings” of ordinary categories coincide, and furthermore its hom-spaces are 2-coskeletal.
Constraining conformal field theories with a higher spin symmetry

We study the constraints imposed by the existence of a single higher spin conserved current on a three-dimensional conformal field theory (CFT). A single higher spin conserved current implies the existence of an infinite number of higher spin conserved currents. The correlation functions of the stress tensor and the conserved currents are then shown to be equal to those of a free field theory. Namely a theory of N free bosons or free fermions. This is an extension of the Coleman–Mandula theorem to CFT’s, which do not have a conventional S-matrix. We also briefly discuss the case where the higher spin symmetries are ‘slightly’ broken.This article is part of a special issue of Journal of Physics A: Mathematical and Theoretical devoted to ‘Higher spin theories and holography’.
The two-user Gaussian fading broadcast channel

This paper presents outerbounds for the two-user Gaussian fading broadcast channel. These outerbounds are based on Costa's entropy power inequality (Costa-EPI) and are formulated mathematically as a feasibility problem. For classes of the two-user Gaussian fading broadcast channel where the outerbound is found to have a feasible solution, we find conditions under which a suitable inner and outer bound meet. For all such cases, this paper provides a partial characterization of the capacity region of the Gaussian two-user fading broadcast channel.
Rules with Discretion and Local Information

To ensure that individual actors take certain actions, community enforcement may be required. This can present a rules-versus-discretion dilemma: it can become impossible to employ discretion based on information that is not widely held, because the wider community is unable to verify how the information was used. Instead, actions may need to conform to simple and widely verifiable rules. We study when discretion in the form of exceptions to a simple rule can be implemented, if the information is shared by the action taker and a second party, who is able to verify for the larger group that an exception is warranted. In particular, we compare protocols where the second party excuses the action taker from taking the action ex ante with protocols where the second party instead forgives a rule-breaking actor ex post. JEL Codes: C73, D82.
Meningitis or epidural abscesses after neuraxial block for removal of infected hip or knee prostheses

Background Infection, whether localized or systemic, can be a relative contraindication to neuraxial anaesthesia. Data correlating neuraxial anaesthesia and the development of meningitis or epidural abscess in this setting are limited. Methods Retrospective chart review was performed on 710 medical records of patients admitted between 1998 and 2009 for removal of potentially infected total hip and total knee prostheses. Ultimately, 474 patients were identified as being infected. Factors that predisposed a patient to an immunocompromised state, and signs and symptoms of infection in the pre-, intra-, and postoperative stages were documented. Bacteraemic patients were reviewed for signs of neuraxial infection. The endpoint of follow-up was development of complications before hospital discharge. Results All 474 patients had removal of the infected prosthesis under neuraxial anaesthesia. Mean patient age was 65.5 yr (58% >65 yr) and mean length of hospital stay was 21 days. Patient characteristics included concurrent disease (65%), steroid use (5.3%), preoperative antibiotic use (50.8%), signs of inflammatory process (84%), bacteraemia (4.2%), and documented positive intraoperative joint cultures (88%). Using clinical standards for diagnosis of central neuraxial infection, patients developed infectious complications (incidence of 0.6% on 95% confidence interval), although three patients had findings attributable to anaesthesia, including epidural haematoma, psoas abscess, and back pain. Conclusions Based on clinical criteria, our findings suggest that the incidence of central nervous system infection after neuraxial anaesthesia in patients with infected hip and knee prostheses is low after neuraxial block.