cssi/SciSciGPT-SciSciNet huggingface dataset:
Assessing the direct economic effects of reallocating irrigation water to alternative uses : concepts and an application

Irrigation water reallocations are playing an increasingly important role in both developed and developing countries. With growing urban and environmental water demands, rising costs for the development of new water supplies, and irrigated agriculture usually including the least economically valuable use of water, transfers of irrigation water to alternative uses are increasing. However, such reallocations are often controversial, and it is often questioned whether the benefits resulting from these transactions are large enough to outweigh the associated costs. This paper reviews the experience with irrigation water transfers, including the involvement of the World Bank. It discusses the problems of assessing the direct economic effects of reallocations, with a focus on the foregone direct benefits in irrigated agriculture. Because foregone direct benefits cannot easily be directly observed, they need to be estimated. However, assessments have shown widely differing estimates -- even when the same methodology was used. The paper reviews the methodologies and model specifications used for estimating foregone direct benefits; illustrates the impact of different model specifications on the magnitude of estimates of foregone direct benefits based on an application in an example case; and draws conclusions with regard to future efforts in assessing reallocation effects, including calculating adequate compensation for farmers. Because estimating the direct benefits of irrigation expansion is methodologically equivalent to estimating foregone direct benefits from reduced irrigation water supplies, the findings have implications for a broader range of water allocation decisions.
INCORPORATING STOCHASTIC HARVESTS INTO AN ANALYSIS OF PRODUCTION: THE U.S. ATLANTIC AND GULF OF MEXICO PELAGIC LONGLINE FLEET

Vessel operators maximize expected utility indirectly through cost-minimizing production decisions subject to stochastic harvests. Data on the Atlantic longline fleet, available from NMFS logbooks, is used for the empirical analysis. An ex ante multi-input cost function that incorporates expected rather than realized output levels is estimated and results are reported.
A transformational characterization of equivalent Bayesian network structures

We present a simple characterization of equivalent Bayesian network structures based on local transformations. The significance of the characterization is twofold. First, we are able to easily prove several new invariant properties of theoretical interest for equivalent structures. Second, we use the characterization to derive an efficient algorithm that identifies all of the compelled edges in a structure. Compelled edge identification is of particular importance for learning Bayesian network structures from data because these edges indicate causal relationships when certain assumptions hold.
Durability/life of fiber composites in hygrothermomechanical environments.

Statistical analysis and multiple regression were used to determine and quantify the significant hygrothermomechanical variables which infuence the tensile durability/life (cycle loading, fatigue) of boron-fiber/epoxy-matrix (B/E) and high-modulus-fiber/epoxy-matrix (HMS/E) composites. The use of the multiple regression analysis reduced the variables from fifteen, assumed initially, to six or less with a probability of greater than 0.999. The reduced variables were used to derive predictive models for compression an intralaminar shear durability/life of B/E and HMS/E composites assuming isoparametric fatigue behavior. The predictive models were subsequently generalized to predict the durability/life of graphite-fiber-r generalized model is of simple form, predicts conservative values compared with measured data and should be adequate for use in preliminary designs.
Dating Business Cycle Turning Points

Abstract This chapter discusses formal quantitative algorithms that can be used to identify business cycle turning points. An intuitive, graphical derivation of these algorithms is presented along with a description of how they can be implemented making very minimal distributional assumptions. We also provide the intuition and detailed description of these algorithms for both simple parametric univariate inference as well as latent-variable multiple-indicator inference using a state-space Markov-switching approach. We illustrate the promise of this approach by reconstructing the inferences that would have been generated if parameters had to be estimated and inferences drawn based on data as they were originally released at each historical date. Our recommendation is that one should wait until one extra quarter of GDP growth is reported or one extra month of the monthly indicators released before making a call of a business cycle turning point. We introduce two new measures for dating business cycle turning points, which we call the “quarterly real-time GDP-based recession probability index” and the “monthly real-time multiple-indicator recession probability index” that incorporate these principles. Both indexes perform quite well in simulation with real-time data bases. We also discuss some of the potential complicating factors one might want to consider for such an analysis, such as the reduced volatility of output growth rates since 1984 and the changing cyclical behavior of employment. Although such refinements can improve the inference, we nevertheless recommend the simpler specifications which perform very well historically and may be more robust for recognizing future business cycle turning points of unknown character.
A dynamic data middleware cache for rapidly-growing scientific repositories

Modern scientific repositories are growing rapidly in size. Scientists are increasingly interested in viewing the latest data as part of query results. Current scientific middleware cache systems, however, assume repositories are static. Thus, they cannot answer scientific queries with the latest data. The queries, instead, are routed to the repository until data at the cache is refreshed. In data-intensive scientific disciplines, such as astronomy, indiscriminate query routing or data refreshing often results in runaway network costs. This severely affects the performance and scalability of the repositories and makes poor use of the cache system. We present Delta a dynamic data middleware cache system for rapidly-growing scientific repositories. Delta's key component is a decision framework that adaptively decouples data objects---choosing to keep some data object at the cache, when they are heavily queried, and keeping some data objects at the repository, when they are heavily updated. Our algorithm profiles incoming workload to search for optimal data decoupling that reduces network costs. It leverages formal concepts from the network flow problem, and is robust to evolving scientific workloads. We evaluate the efficacy of Delta, through a prototype implementation, by running query traces collected from a real astronomy survey.
THE INFORMATIONAL ROLE OF COMMODITY PRICES IN FORMULATING MONETARY POLICY: A REEXAMINATION

Abstract This paper reexamines the issue of whether commodity prices provide useful information for formulating monetary policy through the application of a recent development in time series methodology developed by Toda and Yamamoto [J. Econometrics 66 (1995) 225–250]. We found that commodity prices signal the future direction of the economy.
Signal-based classical emulation of a universal quantum computer

In this paper we present a novel approach to emulating a universal quantum computer with a classical system, one that uses a signal of bounded duration and amplitude to represent an arbitrary quantum state. The signal may be of any modality (e.g., acoustic, electromagnetic, etc), but we focus our discussion here on electronic signals. Unitary gate operations are performed using analog electronic circuit devices, such as four-quadrant multipliers, operational amplifiers, and analog filters, although non-unitary operations may be performed as well. In this manner, the Hilbert space structure of the quantum state, as well as a universal set of gate operations, may be fully emulated classically. The required bandwidth scales exponentially with the number of qubits, however, thereby limiting the scalability of the approach, but the intrinsic parallelism, ease of construction, and classical robustness to decoherence may nevertheless lead to capabilities and efficiencies rivaling that of current high performance computers.
Probability estimation in face of irrelevant information

In this paper, we consider one aspect of the problem of applying decision theory to the design of agents that learn how to make decisions under uncertainty. This aspect concerns how an agent can estimate probabilities for the possible states of the world, given that it only makes limited observations before committing to a decision. We show that the naive application of statistical tools can be improved upon if the agent can determine which of his observations are truly relevant to the estimation problem at hand. We give a framework in which such determinations can be made, and define an estimation procedure to use them. Our framework also suggests several extensions, which show how additional knowledge can be used to improve the estimation procedure still further.
Tremor bands sweep Cascadia

[1] During the slow slip events in Cascadia and Japan, a well-documented feature of nonvolcanic tremor (NVT) is its puzzling slow along-strike migration. But the cause, possible implications, and underlying physics of this long-term tremor migration and its relationship with slow slip remain elusive. Here, we use tremor data recorded by a dense seismic array in Cascadia, and apply a beam-backprojection technique to map the spatiotemporal evolution of tremor with high resolution. It reveals that elongated slip-parallel bands of tremor activity illuminate the slipping part of the plate interface over the time-scale of several hours, and sweep Cascadia along-strike from south to north. We propose that small changes in static stress due to slow slip in a section of the fault cause slip and associated NVT activity in the adjacent section, and the resulting progressive along-strike transfer of stress is responsible for the long-term tremor migration during a slow slip event.
High-Energy Neutrino Astronomy : Science and First Results

We introduce neutrino astronomy starting from the observational fact that Nature accelerates protons and photons to energies in excess of 1020 and 1013 eV, respectively. Although the discovery of cosmic rays dates back a century, we do not know how and where they are accelerated. We review the observations as well as speculations about the sources. Among these gamma ray bursts and active galaxies represent well-motivated speculations because these are also the sources of the highest energy gamma rays, with emission observed up to 20 TeV, possibly higher.
Symmetric Word Equations in Two Positive Definite Letters

CHRISTOPHER J. HILLAR AND CHARLES R. JOHNSONAbstract. A generalized word in two positive deﬁnite matrices A and B isa ﬁnite product of nonzero real powers of A and B. Symmetric words inpositive deﬁnite A and B are positive deﬁnite, and so for ﬁxed B, we canview a symmetric word, S(A,B), as a map from the set of positive deﬁnitematrices into itself. Given positive deﬁnite P, B, and a symmetric word,S(A,B), with positive powers of A, we deﬁne a symmetric word equation asan equation of the form S(A,B) = P. Such an equation is solvable if there isalways a positive deﬁnite solution A for any given B and P. We prove that allsymmetric word equations are solvable. Applications of this fact, methods forsolution, questions about unique solvability (injectivity), and generalizationsare also discussed.
Symmetry-protected topological phases in noninteracting fermion systems

Symmetry-protected topological (SPT) phases are gapped quantum phases with a certain symmetry, which can all be smoothly connected to the same trivial product state if we break the symmetry. For noninteracting fermion systems with time reversal ($\stackrel{\ifmmode \hat{}\else \^{}\fi{}}{T}$), charge conjugation ($\stackrel{\ifmmode \hat{}\else \^{}\fi{}}{C}$), and/or $U(1)$ ($\stackrel{\ifmmode \hat{}\else \^{}\fi{}}{N}$) symmetries, the total symmetry group can depend on the relations between those symmetry operations, such as $\stackrel{\ifmmode \hat{}\else \^{}\fi{}}{T}\stackrel{\ifmmode \hat{}\else \^{}\fi{}}{N}{\stackrel{\ifmmode \hat{}\else \^{}\fi{}}{T}}^{\ensuremath{-}1}=\stackrel{\ifmmode \hat{}\else \^{}\fi{}}{N}$ or $\stackrel{\ifmmode \hat{}\else \^{}\fi{}}{T}\stackrel{\ifmmode \hat{}\else \^{}\fi{}}{N}{\stackrel{\ifmmode \hat{}\else \^{}\fi{}}{T}}^{\ensuremath{-}1}=\ensuremath{-}\stackrel{\ifmmode \hat{}\else \^{}\fi{}}{N}$. As a result, the SPT phases of those fermion systems with different symmetry groups have different classifications. In this paper, we use Kitaev's K-theory approach to classify the gapped free-fermion phases for those possible symmetry groups. In particular, we can view the $U(1)$ as a spin rotation. We find that superconductors with the ${S}_{z}$ spin-rotation symmetry are classified by $Z$ in even dimensions, while superconductors with the time reversal plus the ${S}_{z}$ spin-rotation symmetries are classified by $Z$ in odd dimensions. We show that all 10 classes of gapped free-fermion phases can be realized by electron systems with certain symmetries. We also point out that, to properly describe the symmetry of a fermionic system, we need to specify its full symmetry group that includes the fermion number parity transformation ${(\ensuremath{-})}^{\stackrel{\ifmmode \hat{}\else \^{}\fi{}}{N}}$. The full symmetry group is actually a projective symmetry group.
When Is Command-and-Control Efficient? Institutions, Technology, and the Comparative Efficiency of Alternative Regulatory Regimes for Environmental Protection

Contrary to the conventional wisdom among economists and legal scholars, command-and-control (CAC) environmental regulations are not inherently inefficient or invariably less efficient than alternative "economic" instruments (EI). In fact, CAC regimes can be and have been efficient (producing net social benefits), even more efficient in some cases that alternative EI regimes. Standard economic accounts of CAC are insensitive to the historical, technological, and institutional contexts that can influence (and sometimes determine) the efficiency of alternative regulatory regimes. A regime that is nominally or relatively efficient in one set of circumstances may be nominally or relatively inefficient in another. In some cases, given the marginal costs of pollution control, technological constraints, and existing institutions, CAC can be the most efficient means of achieving a society's environmental protection goals. This paper reviews the empirical literature on environmental regulation and finds that CAC is not inherently inefficient or invariably less efficient that EI. In addition, the paper elaborates a model through five stylized cases, which demonstrate how alternative approaches to environmental regulation are more or less efficient depending on institutional and technological factors that affect overall regulatory costs. Finally, the model is empirically supported by a detailed history of the U.S. Clean Air Act's regulatory regime. Viewed as an evolutionary process, occurring within an institutional and technological framework, it was (nominally and relatively) efficient for Congress to rely, in the early years of federal air pollution control, on CAC regulations, and then in more recent years to begin experimenting with efficiency-enhancing EI.
Information Processing, Optical

This article presents a brief review of the fundamentals of optical information processing. We discuss optical information processing techniques, materials and devices for optical processing, optical pattern recognition, optical security, optical neural computing, and optical memory. Optical image processing algorithms and architectures as well as basic hardware concepts such as the fundamentals of optical spatial light modulators are reviewed. Keywords: optical information processing; optical imaging; optical pattern recognition; optical security; optical spatial light modulators; optical neural computing; optical memory
A verified technique for calibrating space solar cells

Solar cells have been flown on high-altitude balloons for over 24 years, to produce solar cell standards that can be used to set the intensity of solar simulators. The events of a typical balloon calibration flight are reported. These are: the preflight events, including the preflight cell measurements and the assembly of the flight cells onto the solar tracker; the activities at the National Scientific Balloon Facility in Palestine, Texas, including the preflight calibrations, the mating of the tracker and cells onto the balloon, preparations for launch, and the launch; the payload recovery, which includes tracking the balloon by aircraft, terminating the flight, and retrieving the payload. In 1985, the cells flow on the balloon were also flown on a shuttle flight and measured independently. The two measurement methods are compared and shown to agree within 1 percent.
Reasoning about action I: a possible worlds approach

Abstract Reasoning about change is an important aspect of commonsense reasoning and planning. In this paper we describe an approach to reasoning about change for rich domains where it is not possible to anticipate all situations that might occur. The approach provides a solution to the frame problem, and to the related problem that it is not always reasonable to explicitly specify all of the consequences of actions. The approach involves keeping a single model of the world that is updated when actions are performed. The update procedure involves constructing the nearest world to the current one in which the consequences of the actions under consideration hold. The way we find the nearest world is to construct proofs of the negation of the explicit consequences of the expected action, and to remove a premise in each proof from the current world. Computationally, this construction procedure appears to be tractable for worlds like our own where few things tend to change with each action, or where change is regular.
Computable constraints on entanglement-sharing of multipartite quantum states

Negativity is regarded as an important measure of entanglement in quantum informa-tion theory. In contrast to other measures of entanglement, it is easily computable forbipartite states in arbitrary dimensions. In this paper, based on the negativity and re-alignment, we provide a set of entanglement-sharing constraints for multipartite states,where the entanglement is not necessarily limited to bipartite and pure states, thusaiding in the quantification of constraints for entanglement-sharing. These may findapplications in studying many-body systems.
Unstable spiral waves and local Euclidean symmetry in a model of cardiac tissue

This paper investigates the properties of unstable single-spiral wave solutions arising in the Karma model of two-dimensional cardiac tissue. In particular, we discuss how such solutions can be computed numerically on domains of arbitrary shape and study how their stability, rotational frequency, and spatial drift depend on the size of the domain as well as the position of the spiral core with respect to the boundaries. We also discuss how the breaking of local Euclidean symmetry due to finite size effects as well as the spatial discretization of the model is reflected in the structure and dynamics of spiral waves. This analysis allows identification of a self-sustaining process responsible for maintaining the state of spiral chaos featuring multiple interacting spirals.
The Art of Making Everybody Happy: How to Prevent a Secession

In this paper we examine compensation schemes that prevent a threat of secession by all country's regions. We prove that, under quite general assumptions on the distribution of citizens' preferences, there exist transfer schemes that are secession-proof. Moreover, we show that these compensation schemes entail a degree of partial equalization among the regions: the gap between advantageous regions has to be reduced but it should never be completely eliminated. We demonstrate that in the case of a uniform distribution of the nation citizens', the secession-proof conditions generate the 50% compensation rule for disadvantageous regions. JEL Classification Numbers: D70, H20, H73
An introduction to NRQED

We present a pedagogical introduction to NRQED (non-relativistic quantum electrodynamics). NRQED is an effective field theory that describes the interaction of non-relativistic, possibly composite, spin- 1 2 particle with the electromagnetic field. We explain in detail how the NRQED Lagrangian is constructed up to and including order 1∕M2, where M is the mass of the spin- 1 2 particle. As a sample application, we derive the Thomson scattering cross-section for the low energy scattering of a photon and a possibly composite spin- 1 2 particle.
Genome wide comprehensive analysis and web resource development on cell wall degrading enzymes from phyto-parasitic nematodes

Background: The plant cell wall serves as a primary barrier against pathogen invasion. The success of a plant pathogen largely depends on its ability to overcome this barrier. During the infection process, plant parasitic nematodes secrete cell wall degrading enzymes (CWDEs) apart from piercing with their stylet, a sharp and hard mouthpart used for successful infection. CWDEs typically consist of cellulases, hemicellulases, and pectinases, which help the nematode to infect and establish the feeding structure or form a cyst. The study of nematode cell wall degrading enzymes not only enhance our understanding of the interaction between nematodes and their host, but also provides information on a novel source of enzymes for their potential use in biomass based biofuel/bioproduct industries. Although there is comprehensive information available on genome wide analysis of CWDEs for bacteria, fungi, termites and plants, but no comprehensive information available for plant pathogenic nematodes. Herein we have performed a genome wide analysis of CWDEs from the genome sequenced phyto pathogenic nematode species and developed a comprehensive publicly available database. Results: In the present study, we have performed a genome wide analysis for the presence of CWDEs from five plant parasitic nematode species with fully sequenced genomes covering three genera viz. Bursaphelenchus, Glorodera and Meloidogyne. Using the Hidden Markov Models (HMM) conserved domain profiles of the respective gene families, we have identified 530 genes encoding CWDEs that are distributed among 24 gene families of glycoside hydrolases (412) and polysaccharide lyases (118). Furthermore, expression profiles of these genes were analyzed across the life cycle of a potato cyst nematode. Most genes were found to have moderate to high expression from early to late infectious stages, while some clusters were invasion stage specific, indicating the role of these enzymes in the nematode’s infection and establishment process. Additionally, we have also developed a Nematode’s Plant Cell Wall Degrading Enzyme (NCWDE) database as a platform to provide a comprehensive outcome of the present study. Conclusions: Our study provides collective information about different families of CWDEs from five different sequenced plant pathogenic nematode species. The outcomes of this study will help in developing better strategies to curtail the nematode infection, as well as help in identification of novel cell wall degrading enzymes for biofuel/bioproduct industries.
Mining Missing Hyperlinks from Human Navigation Traces: A Case Study of Wikipedia

Hyperlinks are an essential feature of the World Wide Web. They are especially important for online encyclopedias such as Wikipedia: an article can often only be understood in the context of related articles, and hyperlinks make it easy to explore this context. But important links are often missing, and several methods have been proposed to alleviate this problem by learning a linking model based on the structure of the existing links. Here we propose a novel approach to identifying missing links in Wikipedia. We build on the fact that the ultimate purpose of Wikipedia links is to aid navigation. Rather than merely suggesting new links that are in tune with the structure of existing links, our method finds missing links that would immediately enhance Wikipedia's navigability. We leverage data sets of navigation paths collected through a Wikipedia-based human-computation game in which users must find a short path from a start to a target article by only clicking links encountered along the way. We harness human navigational traces to identify a set of candidates for missing links and then rank these candidates. Experiments show that our procedure identifies missing links of high quality.
3-D multiphoton laser scanning confocal microscopy as a probe for subsurface defects in polymers

Summary form only given. Confocal laser scanning microscopy (CLSM) provides a significant improvement in axial resolution over conventional epi-fluorescence microscopy by eliminating out-of-focus fluorescence. This is achieved by using a spatial filter in the form of a confocal aperture. The use of IR leads to a larger penetration depth in materials, providing an opportunity to image thicker samples. Furthermore, it is possible to open up the entire visible spectrum for multiple detection channels. The fluorophore, 4-[N-(2-hydroxyethyl-N-methyl) amino phenyl]-4'-(6-hydroxyhexyl sulfonyl)stilbene (APSS), exhibits a strong two-photon absorption at 800 nm, and green upconverted fluorescence emission.
In the Beginning was Game Semantics

This chapter presents an overview of computability logic—the game-semantically constructed logic of interactive computational tasks and resources. There is only one non-overview, technical section in it, devoted to a proof of the soundness of affine logic with respect to the semantics of computability logic.
Multiplier ideals of monomial ideals

In this note we calculate the multiplier ideal associated to an arbitrary monomial ideal in C^n. We discuss applications to the calculation of log canonical thresholds.
Models of pain and suffering: foundations for an ethic of compassion.

This congress is a testimony to the fact that neurosurgery is deeply concerned with the problem of pain. In fact, neurosurgery is so extensively involved in problems of pain that some neurosurgeons have come to believe they have a special claim on this problem within the medical world. They believe that pain is their province. This is true in some respects, for the history of neurosurgery is marked with many efforts to test pathways of pain conduction and an ever more sophisticated range of surgical procedures from Gasserian ganglionectomy in the nineteenth century to today’s most sophisticated surgical interventions for the relief of pain. On the other hand, this Academy’s program is witness to the attitude that “the problem of pain” is not properly addressed even in the world of medicine until one acquires the knowledge and insight that can be provided by thorough consultation with a wide range of humanistic and scientific disciplines.
Software holography: interferometric data analysis for the challenges of next generation observatories

Next generation radio observatories such as the Murchison Widefield Array (MWA), the Long Wavelength Array (LWA), the LOw Frequency ARray (LOFAR), the Combined Array for Research Millimeter-wave Astronomy (CARMA) and the Square Kilometer Array (SKA) provide a number of challenges for interferometric data analysis. These challenges include heterogeneous arrays, direction-dependent instrumental gain, and refractive and scintillating atmospheric conditions. From the analysis perspective, this means that calibration solutions cannot be described using a single complex gain per antenna. In this paper, we use the optimal map-making formalism developed for cosmic microwave background analyses to extend traditional interferometric radio analysis techniques - removing the assumption of a single complex gain per antenna and allowing more complete descriptions of the instrumental and atmospheric conditions. Due to the similarity with holographic mapping of radio antenna surfaces, we call this extended analysis approach software holography. The resulting analysis algorithms are computationally efficient, unbiased and optimally sensitive. We show how software holography can be used to solve some of the challenges of next generation observations, and how more familiar analysis techniques can be derived as limiting cases.
Lumbar Myelography with Metrizamide: Supplemental Techniques

In a pilot group of 20 sequential patients who underwent metrizamide lumbar myelography, three modifications in technique were compared: (1) a “30” min delayed frontal projection, (2) supine projection of the conus medullaris, and (3) horizontal beam oblique views of the lumbosacral theca. The study showed much better opacification of the lowermost lumbar and the sacral root sleeves by delayed filming in most (70%) of the cases; that the conus medullaris, a structure difficult to visualize by the routine method of prone positioning, could be well visualized routinely with the patient supine; and that larger numbers of lumbar nerve root sleeves could be seen with the same degree of table tilt on horizontal beam oblique than on vertical beam oblique radiography.
Galaxy-scale outflows driven by active galactic nuclei

We present hydrodynamical simulations of major mergers of galaxies and study the effects of winds produced by active galactic nuclei (AGN) on interstellar gas in the AGN’s host galaxy. We consider winds with initial velocities ∼10 000 km s−1 and an initial momentum (energy) flux of ∼τw L/c (∼ 0.01 τw L), with . The AGN wind sweeps up and shock heats the surrounding interstellar gas, leading to a galaxy-scale outflow with velocities ∼1000 km s−1, peak mass outflow rates comparable to the star formation rate and a total ejected gas mass of ∼3 × 109 M⊙. Large momentum fluxes, τw≳ 3, are required for the AGN-driven galactic outflow to suppress star formation and accretion in the black hole’s host galaxy. Less powerful AGN winds (τw≲ 3) still produce a modest galaxy-scale outflow, but the outflow has little global effect on the ambient interstellar gas. We argue that this mechanism of AGN feedback can plausibly produce the high-velocity outflows observed in post-starburst galaxies and the massive molecular and atomic outflows observed in local ultraluminous infrared galaxies. Moreover, the outflows from local ultraluminous infrared galaxies are inferred to have τw∼ 10, comparable to what we find is required for AGN winds to regulate the growth of black holes and set the MBH - σ relation. We conclude by discussing theoretical mechanisms that can lead to AGN wind mass loading and momentum/energy fluxes large enough to have a significant impact on galaxy formation.
Distributed Agreement in Tile Self-assembly

Laboratory investigations have shown that a formal theory of fault-tolerance will be essential to harness nanoscale self-assembly as a medium of computation. Several researchers have voiced an intuition that self-assembly phenomena are related to the field of distributed computing. This paper formalizes some of that intuition. We construct tile assembly systems that are able to simulate the solution of the wait-free consensus problem in some distributed systems. This potentially allows binding errors in tile assembly to be analyzed (and managed) with positive results in distributed computing, as a "blockage" in our tile assembly model is analogous to a crash failure in a distributed computing model. We also define a strengthening of the "traditional" consensus problem, to make explicit an expectation about consensus algorithms that is often implicit in distributed computing literature. We show that solution of this strengthened consensus problem can be simulated by a two-dimensional tile assembly model only for two processes, whereas a three-dimensional tile assembly model can simulate its solution in a distributed system with any number of processes.
NP-hardness of deciding convexity of quartic polynomials and related problems

We show that unless P = NP, there exists no polynomial time (or even pseudo-polynomial time) algorithm that can decide whether a multivariate polynomial of degree four (or higher even degree) is globally convex. This solves a problem that has been open since 1992 when N. Z. Shor asked for the complexity of deciding convexity for quartic polynomials. We also prove that deciding strict convexity, strong convexity, quasiconvexity, and pseudoconvexity of polynomials of even degree four or higher is strongly NP-hard. By contrast, we show that quasiconvexity and pseudoconvexity of odd degree polynomials can be decided in polynomial time.
The Case for a 30m Diameter Submillimeter Telescope on the Antarctic Plateau

A large single-dish submillimeter-wave telescope equipped with a focal plane array containing � 10 4 bolometers and costing about $120M could locate most protogalaxies in the southern sky within a year of operation.
The impact of trade liberalization on household welfare in vietnam

What is the effect of trade liberalization on households in developing countries? To what extent do the poor benefit when local markets are made more accommodative to international trade? The author empirically analyzes the distributional impact of trade policies on households in a low-income country with a large rural economy where labor markets are imperfect. The methodology in this paper, which can be applied to various types of labor market conditions, relates changes in prices attributed to trade reforms to changes in household welfare, income distribution, and poverty using theoretically consistent measures of producer and consumer welfare. The author investigates the effects on poverty and income distribution of national and international market integration in Vietnam's rice sector and fertilizer market between 1993 and 1998, a period of ongoing market reforms when the national poverty rate fell sharply from 59 percent to 37 percent. He finds that when the effects of opening the rice and fertilizer market are isolated, Vietnam's agricultural trade reforms did not contribute to a significant improvement in overall household welfare or decline in poverty over this period. Nonetheless, the liberalization exercise can explain about half of the reduction in poverty incidence among farm households. The results also show that liberalization did not exacerbate income inequality, but did generate gains for rural households across the distribution, particularly the poor, at the expense of urban households.
Valuation, Adverse Selection, and Market Collapses

We study a market for funding real investment where valuation—meaning investors devoting resources to acquiring information about future payoffs—creates an adverse selection problem. Unlike previous models, more valuation is associated with lower market prices and so greater returns to valuation. This strategic complementarity in the capacity to do valuation generates multiple equilibria. With multiple equilibria, the equilibrium without valuation is most efficient despite funding some unprofitable investments. Switches to valuation equilibria, valuation runs, look like credit crunches. A large investor can ensure the efficient equilibrium only if it can precommit to a price and potentially, only if subsidized
Depolymerization of GeO2 and B2O3‐GeO2 Network Glasses by Sb2O3

Binary Sb2O3-GeO2 glasses containing 45 mol% Sb2O3 and ternary Sb2O3-B2O3-GeO2 glasses containing 50 mol% GeO2 were prepared. Their densities (volumes), refractive indices, and infrared spectra were determined, and their colors and high-temperature viscosities were estimated visually. Small amounts of Sb2O3 (∼10 mol%) appear to perturb neither the Ge-O-Ge network nor those B-O-Ge networks with small B/Ge ratios (∼0.2). The B-O-Ge networks with larger B/Ge ratios (∼1.0) depolymerize in the presence of even less Sb2O3. Amounts of Sb2O3 >10 mol% appear to depolymerize the Ge-O-Ge and Ge-O-B networks progressively, possibly with the formation of chains. A structurally sensitive ir isofrequency contour technique developed for ternary glass systems was applied successfully to these Sb2O3-B2O3-GeO2 glasses. These contours can thus readily detect significant network depolymerization in the absence of the usual network modifiers.
The Sum of Its Parts: The Lawyer-Client Relationship in Initial Public Offerings

This Article examines the impact of the quality of a lawyer’s working relationship with his or her client on one of the most important types of capital markets deal in a company’s existence: its initial public offering (IPO). Drawing on data from interviews with equity capital markets lawyers at major law firms, and analyzing data from IPOs in the United States registered with the Securities and Exchange Commission between June 1996 and December 2010, this study finds a strong association between several measures of IPO performance and the familiarity between the lead underwriter and its counsel, as measured by the number of times a particular law firm serves as counsel to a managing underwriter within a relatively short time period. Performance is gauged according to a stock’s opening day returns, price performance over thirty, sixty, and ninety trading days, correct price revision, litigation rates, and the speed at which deals are completed. I also analyze the relationships between the lawyers for the lead underwriter and the lawyers for the issuer. The analysis shows some benefits from familiarity, albeit generally smaller than those associated with the underwriter-lawyer relationship. In all cases, the positive effects of repeated interaction diminish the further back in time the previous collaborations occurred. To rule out selection and reverse causality, I perform a number of tests using smaller subsets of the data to remove observations that are plausibly selection driven. I also show that the relationships between familiarity and deal quality occur independently of the level of the lawyers’ experience. These findings support the conclusion that lawyers’ relational skill can positively influence deal outcomes, independent even of substance and process knowledge. I hypothesize that the core advantage of repeated interaction is the formation of more effective lawyer-client team dynamics.
On staggered checkpointing

A consistent checkpointing algorithm serves a consistent view of a distributed application's state on stable storage. The traditional consistent checkpointing algorithms require different processes to save their state at about the same time. This causes contention for the stable storage, potentially resulting in large overheads. Staggering the checkpoints taken by various processes can reduce checkpoint overhead. The paper presents a simple approach to arbitrarily stagger the checkpoints. The approach requires that the processes take consistent logical checkpoints, as compared to consistent physical checkpoints enforced by existing algorithms. Experimental results on nCube-2 are presented.
Inventories, Stock-Outs, and Production Smoothing

If stock-outs are ignored and if demand shocks are additive, then optimal behaviour requires that the marginal cost of production (MC) be equated with the expected marginal revenue of increasing expected sales by one unit (EMR). However, with more general demand shocks (and still ignoring stock-outs), the excess of MC over EMR has the same sign as the covariance of the slope of the demand curve and the marginal valuation of inventory. The equality of EMR and MC is also broken by taking account of stock-outs, even if demand shocks are additive. If there is a production lag, then taking account of stock-outs implies that optimal behaviour will be characterized by production smoothing even if the cost of production is linear. Two alternative definitions of production smoothing are presented and optimal behaviour in the presence of stock-outs displays each type of smoothing. It is a well-known proposition that a firm producing a storable good under conditions of increasing marginal cost will tend to smooth the time profile of its production relative to the time profile of its sales. The incentive to smooth production arises from the fact that the cost function is a convex function of the level of production. For a given average level of production, average costs can be reduced by reducing the variation in production. Of course, if the cost function is linear in the level of production, then this incentive to smooth production disappears. However, we will demonstrate in this paper that if the possibility of stock-outs is explicitly incorporated into the firm's dynamic optimization problem (i.e. if we impose a non-negativity constraint on inventories), and if there is a lag in production, then optimal behaviour can be characterized by production smoothing even if the cost function is linear.
Designing Privacy-Preserving Smart Meters with Low-Cost Microcontrollers

Smart meters that track fine-grained electricity usage and implement sophisticated usage-based billing policies, e.g., based on time-of-use, are a key component of recent smart grid initiatives that aim to increase the electric grid’s efficiency. A key impediment to widespread smart meter deployment is that fine-grained usage data indirectly reveals detailed information about consumer behavior, such as when occupants are home, when they have guests or their eating and sleeping patterns. Recent research proposes cryptographic solutions that enable sophisticated billing policies without leaking information. However, prior research does not measure the performance constraints of real-world smart meters, which use cheap ultra-low-power microcontrollers to lower deployment costs. In this paper, we explore the feasibility of designing privacy-preserving smart meters using low-cost microcontrollers and provide a general methodology for estimating design costs. We show that it is feasible to produce certified meter readings for use in billing protocols relying on Zero-Knowledge Proofs with microcontrollers such as those inside currently deployed smart meters. Our prototype meter is capable of producing these readings every 10 seconds using a $3.30USD MSP430 microcontroller, while less powerful microcontrollers deployed in today’s smart meters are capable of producing readings every 28 seconds. In addition to our results, our goal is to provide smart meter designers with a general methodology for selecting an appropriate balance between platform performance, power consumption, and monetary cost that accommodates privacy-preserving billing protocols.
Optical interconnects to silicon CMOS

In this paper the author summarizes the rationale for considering optical interconnects to silicon CMOS chips, presents recent results on chip-to-chip interconnects using hybrid-attached quantum well devices, discusses key issues such as latency in optical interconnects, and shows the radical potential of short optical pulses for clock injection, skew and jitter removal, and wavelength-division multiplexed interconnects.
Controllability and Observability of Distributed Gyroscopic Systems

Controllability and observability of a class of distributed gyroscopic systems under pointwise actuators and sensors are presented. The equations of motion are cast in a state space form, in which orthogonality of the eigenfunction is obtined. The controllability and observability conditions in finite dimensions are obtained for a model representing a truncated modal expansion of the distributed system. In infinite dimensions the controllability and observability conditions are obtained through semi-group theory. In both the finite and infinite dimensional models the conditions of controllability and observability are evaluated through the eigenfunctions in an explicit form. The minimum number of actuators and minimum number of sensors needed to control and observe the system are determined by the largest eigenvalue multiplicity. The results are illustrated on vibration control of the axially moving string and the rotating circular plate.
Particle production for a muon storage ring II. Radiation loads

Abstract Efficient production and collection of a large number of muons is needed to make a neutrino factory based on a muon storage ring viable. Results of extensive MARS simulations for 2–30 GeV protons on various targets in a 20 T hybrid solenoid followed by a matching section and decay channel are reported. Part II describes radiation loads on targets, capturing system and shielding.
Optical Properties Of Explosive-Driven Shock Waves In Noble Gases

High explosives have been used to shock-heat rare gases to brightness temperatures up to 36 000 K, with large radiating areas. Temperatures were determined from radiometer signals at both 280 and 520 nm. Shock velocities up to 9 mm/ps were used in both plane and cylindrical geometries. Neon, argon, krypton, and xenon gases at atmospheric initial pressure were examined in plane shocks. Using argon, the effects of increased initial pressure were studied. For cylindrical shock expansion in argon, brightness temperatures were measured over a range of shock velocities from 3 to 9 mm/ps. Up to 4% of the explosive energy was emitted as radiation. The shock waves are found to be reasonable approximations to black-bodies.
The effect of Regulation FD on the properties of management earnings forecasts

Abstract We investigate Regulation FD’s (FD) effect on management earnings forecast properties. We posit FD’s prohibition on private manager-analyst communication reduces (increases) optimism (pessimism) in management earnings forecasts. Prior to FD, managers could avoid publicly retracting prior optimistic forecasts by privately communicating with analysts, who could lower investor expectations with a new analyst forecast. After FD, managers with optimistic forecasts must either publicly admit their optimism by issuing a new management forecast or they must negatively surprise investors at the earnings announcement. Further, FD forces managers to use public forecasts instead of private communications to establish beatable expectations. Our evidence suggests FD reduced optimism in management forecasts. This reduction in optimistic bias is not offset by an increase in pessimistic bias. Consistent with this, we further find post-FD improvements in forecast accuracy and informativeness. We find no such changes around several potentially confounding events or for foreign firms surrounding FD. Overall, our evidence suggests FD improved firms’ forecast properties (less bias, greater accuracy, and greater informativeness).
Contribution of Time-of-Flight Information to Limited Angle Positron Tomography

Limited-angle emission tomography has been investigated using a two-dimensional phantom to generate positron events simulating a camera with two opposed parallel position-sensitive detectors collecting data within a 90° cone. The data, backprojected onto lines passing through the phantom volume, is used with a matrix reconstruction method to provide two-dimensional images. Image quality has been measured using the standard deviation of the reconstructions with respect to the original phantom. The application of Phillips-Twomey smoothing to the deconvolution matrices has substantially improved the original reconstructions, a factor of 1.9 in signal to noise ratio, giving S/N = 3.4 for a phantom having an average of 150 events/pixel. Using photon time-of-flight to restrict the reconstruction volume a further considerable improvement is made. When the time-of-flight limited the contributing volume to 4 lines out of 11 the improvement was another factor of 1.9 giving SN = 6.0 for the same phantom. Comparable increases in signal to noise ratios are expected for three-dimensional reconstructions.