cssi/SciSciGPT-SciSciNet huggingface dataset:
Revenue Insurance for Georgia and South Carolina Peaches

We estimate actuarially fair premium rates for yield and revenue insurance for Georgia and South Carolina peaches. The premium rates for both products decrease at a decreasing rate as the mean farm-level yield increases. In general, the premium rate for revenue insurance exceeds the premium rate for yield insurance for a given coverage level and expected yield. Although the revenue and yield insurance rates differ in a statistical sense, they do not appear to differ in an economic sense except at high coverage levels for growers with very high yields.
Role of avionics in trajectory-based operations

Air Traffic Management automation systems are being developed and fielded to assist controllers in handling more aircraft and larger airspace per controller. Many of these systems are time-based and built upon predicting the aircraft trajectories as accurately as possible. Trajectories of multiple aircraft are strategically deconflicted by modifying appropriate trajectories and issuing corresponding clearances to the aircraft. However, disturbances and modeling errors will cause aircraft to deviate from their predicted trajectories and controllers will need to take action to keep trajectories free from conflict. The associated increase in workload will reduce the usefulness of these automation systems. On-board avionics can help improve the accuracy of the trajectory prediction system in three ways: (1) sharing aircraft state information to improve the performance of the ground trajectory prediction system, (2) sharing airborne prediction results and allowable minimum and maximum arrival times at key route waypoints, and, finally, (3) by applying feedback control onboard the aircraft to autonomously correct for disturbances encountered in flight. This presents an analysis of trajectory dispersion with and without airborne time of arrival control, presents an operational concept for air/ground trajectory negotiation, discusses integration with airborne merging and spacing algorithms, and raises concerns about challenges in implementing this integrated solution.
Introducing the Target-Matrix Paradigm for Mesh Optimization via Node-Movement

A general-purpose algorithm for mesh optimization via nodemovement, known as the Target-Matrix Paradigm, is introduced. The algorithm is general purpose in that it can be applied to a wide variety of mesh and element types, and to various commonly recurring mesh optimization problems such as shape improvement, and to more unusual problems like boundary-layer preservation with sliver removal, high-order mesh improvement, and edge-length equalization. The algorithm can be considered to be a direct optimization method in which weights are automatically constructed to enable definitions of application-specific mesh quality. The high-level concepts of the paradigm have been implemented in the Mesquite mesh-improvement library, along with a number of concrete algorithms that address mesh quality issues such as those shown in the examples of the present paper.
Three-Dimensional Topological Insulators

Topological insulators in three dimensions are nonmagnetic insulators that possess metallic surface states (SSs) as a consequence of the nontrivial topology of electronic wavefunctions in the bulk of the material. They are the first known examples of topological order in bulk solids. We review the basic phenomena and experimental history, starting with the observation of topological insulator behavior in BixSb1−x by angle and spin-resolved photoemission spectroscopy (spin-ARPES) and continuing through measurements on other materials and by other probes. A self-contained introduction to the single-particle theory is then given, followed by the many-particle definition of a topological insulator as a material with quantized magnetoelectric polarizability. The last section reviews recent work on strongly correlated topological insulators and new effects that arise from the proximity effect between a topological insulator and a superconductor. Although this article is not intended to be a comprehensive review...
Physical Model of the Immune Response of Bacteria Against Bacteriophage Through the Adaptive CRISPR-Cas Immune System

Bacteria and archaea have evolved an adaptive, heritable immune system that recognizes and protects against viruses or plasmids. This system, known as the CRISPR-Cas system, allows the host to recognize and incorporate short foreign DNA or RNA sequences, called ‘spacers’ into its CRISPR system. Spacers in the CRISPR system provide a record of the history of bacteria and phage coevolution. We use a physical model to study the dynamics of this coevolution as it evolves stochastically over time. We focus on the impact of mutation and recombination on bacteria and phage evolution and evasion. We discuss the effect of different spacer deletion mechanisms on the coevolutionary dynamics. We make predictions about bacteria and phage population growth, spacer diversity within the CRISPR locus, and spacer protection against the phage population.
Strongly tilting truncated path algebras

For any truncated path algebra Λ, we give a structural description of the modules in the categories \({\mathcal{P}^{<\infty}(\Lambda\text{-}{\rm mod})}\) and \({\mathcal{P}^{<\infty}(\Lambda\text{-}{\rm mod})}\) , consisting of the finitely generated (resp. arbitrary) Λ-modules of finite projective dimension. We deduce that these categories are contravariantly finite in Λ−mod and Λ-Mod, respectively, and determine the corresponding minimal \({\mathcal{P}^{<\infty}}\) -approximation of an arbitrary Λ-module from a projective presentation. In particular, we explicitly construct—based on the Gabriel quiver Q and the Loewy length of Λ—the basic strong tilting module ΛT (in the sense of Auslander and Reiten) which is coupled with \({\mathcal{P}^{<\infty}(\Lambda\text{-}{\rm mod})}\) in the contravariantly finite case. A main topic is the study of the homological properties of the corresponding tilted algebra \({\tilde{\Lambda} = {\rm End}_\Lambda(T)^{\rm op}}\) , such as its finitistic dimensions and the structure of its modules of finite projective dimension. In particular, we characterize, in terms of a straightforward condition on Q, the situation where the tilting module \({T_{\tilde{\Lambda}}}\) is strong over \({\tilde{\Lambda}}\) as well. In this Λ-\({\tilde{\Lambda}}\)-symmetric situation, we obtain sharp results on the submodule lattices of the objects in \({\mathcal{P}^{<\infty}({\rm Mod}\text{-}\tilde{\Lambda})}\) , among them a certain heredity property; it entails that any module in \({\mathcal{P}^{<\infty}({\rm Mod}\text{-}\tilde{\Lambda})}\) is an extension of a projective module by a module all of whose simple composition factors belong to \({\mathcal{P}^{<\infty}({\rm Mod}\text{-}\tilde{\Lambda})}\) .
Synthesis of (2S,3S)-β-methyltryptophan

Abstract Nα-Fmoc-protected (2S,3S)-β-methyltryptophan has been synthesized by asymmetric synthesis through the aid of an oxazolidinone auxiliary. Coupling of the mixed anhydride of Nin-Boc-protected indoleacrylic acid to the oxazolidinone auxiliary was achieved by lithium bromide and N,N-dimethylpyridine (DMAP). This reaction is milder and more convenient to run than the traditional conditions using butyl lithium.
Cluster abundance and large-scale structure

We use the presently observed number density of large X-ray clusters and linear mass power spectra to constrain the shape parameter ($\Gamma$), the spectral index ($n$), the amplitude of matter density perturbations on the scale of $8 h^{-1}$Mpc ($\sigma_8$), and the redshift distortion parameter ($\beta$). The non-spherical-collapse model as an improvement to the Press-Schechter formula is used and yields significantly lower $\sigma_8$ and $\beta$. An analytical formalism for the formation redshift of halos is also derived.
Dications of Fluorenylidenes. The Effect of Substituent Electronegativity and Position on the Antiaromaticity of Substituted Tetrabenzo[5.5]fulvalene Dications

Oxidation of 3,6-disubstituted tetrabenzo[5.5]fulvalenes by SbF5 results in the formation of dications that behave like two antiaromatic fluorenyl cations connected by a single bond. Both fluorenyl systems exhibit the paratropic shifts and nucleus independent chemical shifts (NICS) characteristic of antiaromatic species. Comparison with analogous 2,7-disubstituted tetrabenzo[5.5]fulvalenes reveals that the antiaromaticity of the substituted ring system can be altered substantially by changes in the placement of the substituents, possibly due to changes in the delocalization of charge in the system. Substituents in the 3,6-position decrease the antiaromaticity because of the increase in the benzylic resonance compared to 2,7-substituents.
Incremental Parser Generation for Tree Adjoining Grammars

This paper describes the incremental generation of parse tables for the LR-type parsing of Tree Adjoining Languages (TALs). The algorithm presented handles modifications to the input grammar by updating the parser generated so far. In this paper, a lazy generation of LR-type parsers for TALs is defined in which parse tables are created by need while parsing. We then describe an incremental parser generator for TALs which responds to modification of the input grammar by updating parse tables built so far.
Access vs. bandwidth in codes for storage

Maximum distance separable (MDS) codes are widely used in storage systems to protect against disks (nodes) failures. An (n, k, l) MDS code uses n nodes of capacity l to store k information nodes. The MDS property guarantees the resiliency to any n − k node failures. An optimal bandwidth (resp. optimal access) MDS code communicates (resp. accesses) the minimum amount of data during the recovery process of a single failed node. It was shown that this amount equals a fraction of 1/(n − k) of data stored in each node. In previous optimal bandwidth constructions, l scaled polynomially with k in codes with asymptotic rate < 1. Moreover, in constructions with constant number of parities, i.e. rate approaches 1, l scaled exponentially w.r.t. k. In this paper we focus on the practical case of n − k = 2, and ask the following question: Given the capacity of a node l what is the largest (w.r.t. k) optimal bandwidth (resp. access) (k + 2, k, l) MDS code. We give an upper bound for the general case, and two tight bounds in the special cases of two important families of codes.
Geometry of online packing linear programs

We consider packing LP's with m rows where all constraint coefficients are normalized to be in the unit interval. The n columns arrive in random order and the goal is to set the corresponding decision variables irrevocably when they arrive to obtain a feasible solution maximizing the expected reward. Previous (1−e)-competitive algorithms require the right-hand side of the LP to be $\Omega (\frac{m}{\epsilon^2} \log \frac{n}{\epsilon})$, a bound that worsens with the number of columns and rows. However, the dependence on the number of columns is not required in the single-row case and known lower bounds for the general case are also independent of n. Our goal is to understand whether the dependence on n is required in the multi-row case, making it fundamentally harder than the single-row version. We refute this by exhibiting an algorithm which is (1−e)-competitive as long as the right-hand sides are $\Omega (\frac{m^2}{\epsilon^2} \log \frac{m}{\epsilon})$. Our techniques refine previous PAC-learning based approaches which interpret the online decisions as linear classifications of the columns based on sampled dual prices. The key ingredient of our improvement comes from a non-standard covering argument together with the realization that only when the columns of the LP belong to few 1-d subspaces we can obtain small such covers; bounding the size of the cover constructed also relies on the geometry of linear classifiers. General packing LP's are handled by perturbing the input columns, which can be seen as making the learning problem more robust.
Estimating changes in urban ozone concentrations due to life cycle emissions from hydrogen transportation systems

Hydrogen has been proposed as a low polluting alternative transportation fuel that could help improve urban air quality. This paper examines the potential impact of introducing a hydrogen-based transportation system on urban ambient ozone concentrations. This paper considers two scenarios, where significant numbers of new hydrogen vehicles are added to a constant number of gasoline vehicles. In our scenarios hydrogen fuel cell vehicles (HFCVs) are introduced in Sacramento, California at market penetrations of 9% and 20%. From a life cycle analysis (LCA) perspective, considering all the emissions involved in producing, transporting, and using hydrogen, this research compares three hypothetical natural gas to hydrogen pathways: (1) on-site hydrogen production; (2) central hydrogen production with pipeline delivery; and (3) central hydrogen production with liquid hydrogen truck delivery. Using a regression model, this research shows that the daily maximum temperature correlates well with atmospheric ozone formation. However, increases in initial VOC and NOx concentrations do not necessarily increase the peak ozone concentration, and may even cause it to decrease. It is found that ozone formation is generally limited by NOx in the summer and is mostly limited by VOC in the fall in Sacramento. Of the three hydrogen pathways, the truck delivery pathway contributes the most to ozone precursor emissions. Ozone precursor emissions from the truck pathway at 9% market penetration can cause additional 3-h average VOC (or NOx) concentrations up to approximately 0.05% (or 1%) of current pollution levels, and at 20% market penetration up to approximately 0.1% (or 2%) of current pollution levels. However, all of the hydrogen pathways would result in very small (either negative or positive) changes in ozone air quality. In some cases they will result in worse ozone air quality (mostly in July, August, and September), and in some cases they will result in better ozone air quality (mostly in October). The truck pathway tends to cause a much wider fluctuation in degradation or improvement of ozone air quality: percentage changes in peak ozone concentrations are approximately −0.01% to 0.04% for the assumed 9% market penetration, and approximately −0.03% to 0.1% for the 20% market penetration. Moreover, the 20% on-site pathway occasionally results in a decrease of about −0.1% of baseline ozone pollution. Compared to the current ambient pollution level, all three hydrogen pathways are unlikely to cause a serious ozone problem for market penetration levels of HFCVs in the 9–20% range.
A Discrepancy Lower Bound for Information Complexity

This paper provides the first general technique for proving information lower bounds on two-party unbounded-rounds communication problems. We show that the discrepancy lower bound, which applies to randomized communication complexity, also applies to information complexity. More precisely, if the discrepancy of a two-party function f with respect to a distribution $$\mu $$μ is $$Disc_\mu f$$Discμf, then any two party randomized protocol computing f must reveal at least $$\Omega (\log (1/Disc_\mu f))$$Ω(log(1/Discμf)) bits of information to the participants. As a corollary, we obtain that any two-party protocol for computing a random function on $$\{0,1\}^n\times \{0,1\}^n$${0,1}n?{0,1}n must reveal $$\Omega (n)$$Ω(n) bits of information to the participants. In addition, we prove that the discrepancy of the Greater-Than function is $$\Omega (1/\sqrt{n})$$Ω(1/n), which provides an alternative proof to the recent proof of Viola (Proceedings of the twenty-fourth annual ACM-SIAM symposium on discrete algorithms, SODA 2013, New Orleans, LA, USA, 6---8 Jan 2013, pp 632---651, 2013) of the $$\Omega (\log n)$$Ω(logn) lower bound on the communication complexity of this well-studied function and, combined with our main result, proves the tight $$\Omega (\log n)$$Ω(logn) lower bound on its information complexity. The proof of our main result develops a new simulation procedure that may be of an independent interest. In a followup breakthrough work of Kerenidis et al. (53rd annual IEEE symposium on foundations of computer science, FOCS 2012, New Brunswick, NJ, USA, 20---23 Oct 2012, pp 500---509, 2012), our simulation procedure served as a building block towards a proof that almost all known lower bound techniques for communication complexity (and not just discrepancy) apply to information complexity as well.
PARP16 is a tail-anchored endoplasmic reticulum protein required for the PERK- and IRE1α-mediated unfolded protein response

Chang and colleagues reveal that the poly(ADP-ribose) polymerase PARP16 participates in the endoplasmic reticulum (ER) stress response. They report that PARP16 is a transmembrane ER protein that PARsylates and activates PERK and IRE1α in response to ER stress.
Optimal precision in the presence of uncertainty

We consider the problem of achieving coordinated actions in a real-time distributed system. In particular, we consider how tightly processors can be guaranteed to perform a particular action, in a system where message transmission is guaranteed, but there is some uncertainty in message transmission time. We present an algorithm to achieve optimal precision in arbitrary networks.
DCMS: A data analytics and management system for molecular simulation

Molecular Simulation (MS) is a powerful tool for studying physical/chemical features of large systems and has seen applications in many scientific and engineering domains. During the simulation process, the experiments generate a very large number of atoms and intend to observe their spatial and temporal relationships for scientific analysis. The sheer data volumes and their intensive interactions impose significant challenges for data accessing, managing, and analysis. To date, existing MS software systems fall short on storage and handling of MS data, mainly because of the missing of a platform to support applications that involve intensive data access and analytical process. In this paper, we present the database-centric molecular simulation (DCMS) system our team developed in the past few years. The main idea behind DCMS is to store MS data in a relational database management system (DBMS) to take advantage of the declarative query interface (i.e., SQL), data access methods, query processing, and optimization mechanisms of modern DBMSs. A unique challenge is to handle the analytical queries that are often compute-intensive. For that, we developed novel indexing and query processing strategies (including algorithms running on modern co-processors) as integrated components of the DBMS. As a result, researchers can upload and analyze their data using efficient functions implemented inside the DBMS. Index structures are generated to store analysis results that may be interesting to other users, so that the results are readily available without duplicating the analysis. We have developed a prototype of DCMS based on the PostgreSQL system and experiments using real MS data and workload show that DCMS significantly outperforms existing MS software systems. We also used it as a platform to test other data management issues such as security and compression.
Efficient Active Algorithms for Hierarchical Clustering

Advances in sensing technologies and the growth of the internet have resulted in an explosion in the size of modern datasets, while storage and processing power continue to lag behind. This motivates the need for algorithms that are efficient, both in terms of the number of measurements needed and running time. To combat the challenges associated with large datasets, we propose a general framework for active hierarchical clustering that repeatedly runs an off-the-shelf clustering algorithm on small subsets of the data and comes with guarantees on performance, measurement complexity and runtime complexity. We instantiate this framework with a simple spectral clustering algorithm and provide concrete results on its performance, showing that, under some assumptions, this algorithm recovers all clusters of size Ω(log n) using O(n log2 n) similarities and runs in O(n log3 n) time for a dataset of n objects. Through extensive experimentation we also demonstrate that this framework is practically alluring.
Suspect Disrespect toward the Police

Research shows that suspects' behavior influences police officers' decisions. Those who are disrespectful to the police are more likely to have that behavior reciprocated. To date, the factors influencing whether suspects will show deference remain largely unexamined. Guided by social interactionist theory and recent developments in urban sociology, we use systematic social observations and census data to investigate. We find that elevated levels of police force can induce suspect disrespect, but more subtle forms tend to have the opposite effect. The size of the audiences observing the encounter also influences whether suspects behave disrespectfully. Hypothesized links between disinhibiting factors such as intoxicants and disrespect are confirmed. Excluding traffic encounters, suspects in disadvantaged neighborhoods are less likely to show defference. This finding helps explain why officers encountering African Americans are the targets of disrespect.
Bladder Distention and Pyelectasis in the Male Fetus: Causes, Comparisons, and Contrasts

The objective of this paper was to determine if prenatal sonographic findings can accurately differentiate between the causes of bladder distention and pyelectasis in the male fetus. Twenty-one cases were evaluated for the presence of oligohydramnios, posterior urethral dilation, bladder wall thickening, urachal patency, cortical thinning, cortical cysts, and increased renal echogenicity. Postnatal diagnosis included posterior urethral valves (10 cases), prune belly syndrome (four cases), vesicoureteral reflux (four cases), left ureterovesical junction obstruction (one case), and nonrefluxing, nonobstructive megacystis‐megaureter (two cases). Oligohydramnios was present in eight of 10 cases of posterior urethral valves and in one of four cases of prune belly syndrome. A dilated posterior urethra was noted in seven of 10 cases of posterior urethral valves and transiently in two of four cases of prune belly syndrome. Bladder wall thickening developed in all cases of posterior urethral valves and was noted in two of four patients with prune belly syndrome. A patent urachus likewise was identified in two of four cases of prune belly syndrome. The presence of oligohydramnios, progressive bladder wall thickening, and dilated posterior urethra was most suggestive of posterior urethral valves, whereas the presence of a patent urachus was most suggestive of prune belly syndrome. The presence of pyelectasis and megacystis without additional amniotic fluid, bladder, urethral, or renal abnormalities was most suggestive of vesicoureteral reflux, ureterovesical junction obstruction, or nonrefluxing, nonobstructive megacystis‐ megaureter. Owing to the overlap and evolution of these findings, close follow-up evaluation is recommended. KEY WORDS: Posterior urethral valves; Prune belly syndrome; Pyelectasis; Bladder, distention.
Misguided Retribution: Criminalization of Pregnant Women Who Take Drugs

This article addresses the attempts to use criminal punishment to respond to pregnant women who take drugs in the United States. Although many have discussed why this approach is harmful, none have...
The Global Enforcement of Human Rights: The Unintended Consequences of Transnational Litigation

ABSTRACT In the last few years, a growing number of individuals whose basic rights are violated have filed transnational human rights claims in foreign countries. By placing the individual as a holder of basic rights at the core of the process of development, the capability approach, as put forward by Amartya Sen and Martha Nussbaum, provides a fertile theoretical framework to assess translational human rights litigation. The paper shows that transnational claims are problematic in two regards: 1) they undermine development by discouraging foreign companies from investing in countries that are sources of transnational claims and by weakening local governments and judiciaries; 2) the conflict resolution process is inadequate because financial and practical constraints prevent stakeholders from directly participating in the process, and because assessing damages and enforcing award judgments will most likely be unfair. The path to be taken involves developing a stronger rule of law, stronger local instituti...
Contour lines of the two-dimensional discrete Gaussian free field

The 2-dimensional massless Gaussian free field (GFF) is a 2-dimensional-time analog of Brownian motion. Just as Brownian motion is a scaling limit of simple random walks and various other 1-dimensional systems, the GFF is a scaling limit of several discrete models for random surfaces. Among these is the discrete Gaussian free field (DGFF), also called the harmonic crystal. We presently discuss the basic definitions and describe the main results of the current work, postponing an overview of the history and general context to §1.3.
Capacity Gain From Two-Transmitter and Two-Receiver Cooperation

Capacity improvement from transmitter and receiver cooperation is investigated in a two-transmitter, two-receiver network with phase fading and full channel state information (CSI) available at all terminals. The transmitters cooperate by first exchanging messages over an orthogonal transmitter cooperation channel, then encoding jointly with dirty-paper coding. The receivers cooperate by using Wyner-Ziv compress-and-forward over an analogous orthogonal receiver cooperation channel. To account for the cost of cooperation, the allocation of network power and bandwidth among the data and cooperation channels is studied. It is shown that transmitter cooperation outperforms receiver cooperation and improves capacity over noncooperative transmission under most operating conditions when the cooperation channel is strong. However, a weak cooperation channel limits the transmitter cooperation rate; in this case, receiver cooperation is more advantageous. Transmitter-and-receiver cooperation offers sizable additional capacity gain over transmitter-only cooperation at low signal-to-noise ratio (SNR), whereas at high SNR transmitter cooperation alone captures most of the cooperative capacity improvement.
Effect of Crystallization of the Grain‐Boundary Phase on the Thermal Diffusivity of a Sialon Ceramic

Crystallization of the glassy grain-boundary phase in a series of sialon ceramics fabricated using a range of hot-pressing schedules increased the thermal diffusivity at room temperature by an average of =lo%. For samples made by a given hotpressing schedule, the relative difference in thermal diffusivity between composites containing a glassy grain-boundary phase and those in which this phase had crystallized decreased with increasing temperature. This behavior is attributed to enhanced phonon scattering in the crystalline grain-boundary phase.
RECENT ADVANCES IN SODIUM INTERCALATION POSITIVE ELECTRODE MATERIALS FOR SODIUM ION BATTERIES

Significant progress has been achieved in the research on sodium intercalation compounds as positive electrode materials for Na-ion batteries. This paper presents an overview of the breakthroughs in the past decade for developing high energy and high power cathode materials. Two major classes, layered oxides and polyanion compounds, are covered. Their electrochemical performance and the related crystal structure, solid state physics and chemistry are summarized and compared.
The formation of high-mass black holes in low-mass X-ray binaries

Abstract We suggest that high-mass black holes; i.e., black holes of several solar masses, can be formed in binaries with low-mass main-sequence companions, provided that the hydrogen envelope of the massive star is removed in common envelope evolution which begins only after the massive star has finished He core burning.
Upgrading the Local Ergodic Theorem for Planar Semi-dispersing Billiards

The Local Ergodic Theorem (also known as the ‘Fundamental Theorem’) gives sufficient conditions under which a phase point has an open neighborhood that belongs (mod 0) to one ergodic component. This theorem is a key ingredient of many proofs of ergodicity for billiards and, more generally, for smooth hyperbolic maps with singularities. However, the proof of that theorem relies upon a delicate assumption (Chernov-Sinai Ansatz), which is difficult to check for some physically relevant models, including gases of hard balls. Here we give a proof of the Local Ergodic Theorem for two dimensional billiards without using the Ansatz.
Ring expansion of trans-divinyl ethylene oxide by oxonium ylide [2,3] sigmatropic rearrangement

Oxonium ylide [2,3] sigmatropic rearrangement of trans-divinyl ethylene oxide is observed upon its exposure to ethyl or t-butyl diazoacetate in the presence of either Rh(II) or Cu(II) catalysts to produce cis-6-vinyl-3,6-dihydropyran-2-carboxylates.
Valuing Ecosystem Services

SUMMARY This paper explores two methods for valuing ecosystems by valuing the services that they yield to various categories of user and that are not directly valued in the market, and illustrates the usefulness of these methods with an application to the valuation of mangrove ecosystems in Thailand. The first method is known as the production function approach and relies on the fact that ecosystems may be inputs into the production of other goods or services that are themselves marketed, such as fisheries. I discuss issues that arise in measuring the input into fisheries, particularly those due to the fact that the fishery stock is changing over time, and the shadow value of the ecosystem consists in its contribution to the maintenance of the stock as well as its contribution to current output. The second method is known as the expected damage approach and is used to value the services of storm protection in terms of the reduction in expected future storm damage that the ecosystem can provide. These two methods are shown to yield very different valuations of ecosystems from those that would be derived by the methods typically used in cost-benefit analyses. I argue that they represent a significant improvement on current practice.
A thermal exitance and energy balance model for forest canopies

A steady-state thermal radiance model to compute thermal exitance and energy balance within forest canopies is described. The model treats fully leafed canopies as discrete ensembles of leaves partitioned into slope-angle and height classes. Short-wave energy flux absorbed within the canopy is estimated by solving simplified radiosity equations. Sensible heat exchange is estimated using a logarithmic wind profile above the canopy and a modified exponential profile within the canopy. The latent heat boundary layer resistance is estimated from site-specific measurements summarizing the effects of solar irradiance, air temperature, and vapor pressure deficit on stomatal conductance. Example comparisons for a dense spruce-fir forest study site in central Maine are given. For clear days the resulting root mean square error in modeled versus measured canopy temperatures was 1.2/spl deg/C. Corresponding errors in latent and sensible heat flux energy budget terms were 30 and 32 W/m/sup -2/, respectively. For partly cloudy days the root mean square error in predicted temperature was 1.0/spl deg/C and corresponding errors in latent and sensible heat were 40 and 110 W/m/sup -2/. >
Facile synthesis of thiazoles via an intramolecular thia-Michael strategy

Abstract A mild and efficient method for the synthesis of substituted thiazoles is reported via one-pot N -desilylation, thioacylation/oxythioacylation/thiothioacylation followed by thia-Michael cycloisomerisation. This method has a general applicability to introduce various oxo and thio functionalities including aliphatic and aromatic moieties, especially at the C2-position of thiazoles.
Ferrographic and spectrometer oil analysis from a failed gas turbine engine

An experimental gas turbine engine was destroyed as a result of the combustion of its titanium components. It was concluded that a severe surge may have caused interference between rotating and stationary compressor parts that either directly or indirectly ignited the titanium components. Several engine oil samples (before and after the failure) were analyzed with a Ferrograph, and with plasma, atomic absorption, and emission spectrometers to see if this information would aid in the engine failure diagnosis. The analyses indicated that a lubrication system failure was not a causative factor in the engine failure. Neither an abnormal wear mechanism nor a high level of wear debris was detected in the engine oil sample taken just prior to the test in which the failure occurred. However, low concentrations (0.2 to 0.5 ppm) of titanium were evident in this sample and samples taken earlier. After the failure, higher titanium concentrations (2 ppm) were detected in oil samples taken from different engine locations. Ferrographic analysis indicated that most of the titanium was contained in spherical metallic debris after the failure. The oil analyses eliminated a lubrication system bearing or shaft seal failure as the cause of the engine failure. Previously announced in STAR as N83-12433
Building Routines: Learning, Cooperation, and the Dynamics of Incomplete Relational Contracts

This paper studies how agents with conflicting interests learn to cooperate when the details of cooperation are not common knowledge. It considers a repeated game in which one player has incomplete information about when and how her partner can provide benefits. Initially, monitoring is imperfect and cooperation requires inefficient punishment. As the players' common his tory grows, the uninformed player can learn to monitor her partner's actions, which allows players to establish more efficient cooperative routines. Because revealing information is costly, it may be optimal not to reveal all the existing information, and efficient equilibria can be path-dependent. (JEL C73, D82, D83, D86) This paper studies how agents with conflicting interests go about developing a successful cooperative relationship when the details of cooperation are not common knowledge. In cir cumstances where formal contracts are unavailable or inconvenient, agents frequently rely on informal cooperative agreements?or relational contracts?to resolve incentive conflicts. In fact, whenever the interested parties have better information than do outside courts, relational con tracts can outperform formal contracts by allowing agents to adapt their joint behavior to contin gencies that cannot be assessed by third parties.1 The starting point of this paper is to recognize that even when agents have better information than outside courts, this does not mean that the details of how and when cooperation should occur are common knowledge between the parties. For instance, a new plant manager may not have a complete understanding of what her produc tion teams can and cannot do, a firm's CEO may have only partial understanding of how research teams should operate, and so on. The question is then: how do players go about building a com mon agreement? Or, formulated in a slightly different way, how do they go about specifying the contingencies of their relational contract? The model developed in the paper considers two players engaged in an infinitely repeated game with asymmetric information. In each period, player 1 decides to stay (and interact with player 2) or exit (and skip interaction for one period). Staying is costly for player 1 and yields a benefit for player 2. If player 1 stays, player 2 can reciprocate by taking some action from a set of available actions, which is randomly drawn in each period from a countable superset. Player 2 can take actions of two types: unproductive actions that are costless to player 2 but yield zero benefit to
Sifting through Nine Years of NIST Clock Data with TA2

We have extended the new TA2 post-processed time scale at the NIST beyond our previous reports to include all of the period from January 1984 to December 1992. Derived from the ensemble of clocks at the NIST, this time scale includes the benefits of several recent refinements to the algorithm. By iteratively running the algorithm on the ensemble clock data and characterizing anomalous behaviour in the dominant individual clocks of the ensemble between iterations, we obtain an optimized scale which benefits from the informed anticipation of that anomalous behaviour and demonstrates an overall decrease in scale disruption. Herein we discuss changes to the TA2 algorithm that we made while processing the eight-year run, our method of characterizing anomalous behaviour in individual clocks, the way unanticipated anomalous behaviour is dealt with by the algorithm, and our resulting nine-year time scale.
Gravitational radiation damping and the three-body problem

A model of three-body motion is developed which includes the effects of gravitational radiation reaction. The radiation reaction due to the emission of gravitational waves is the only post-Newtonian effect that is included here. For simplicity, all of the motion is taken to be planar. Two of the masses are viewed as a binary system, and the third mass, whose motion will be a fixed orbit around the centre-of-mass of the binary system, is viewed as a perturbation. This model aims to describe the motion of a relativistic binary pulsar that is perturbed by a third mass. Numerical integration of this simplified model reveals that, given the right initial conditions and parameters, one can see resonances. These (m, n) resonances are defined by the resonance condition, mw = 2nΩ, where m and n are relatively prime integers, and w and Ω are the angular frequencies of the binary orbit and third mass orbit (around the centre-of-mass of the binary), respectively. The resonance condition consequently fixes a value for the semimajor axis of the binary orbit for the duration of the resonance; therefore the binary energy remains constant on average, while its angular momentum changes during the resonance.
A note on UMD spaces and transference in vector-valued function spaces

A Banach space X is called an HT space if the Hilbert transform is bounded from Lp(X) into Lp(X), where 1 < p < ∞. We introduce the notion of an ACF Banach space, that is, a Banach space X for which we have an abstract M. Riesz Theorem for conjugate functions in Lp(X), 1 < p < ∞. Berkson, Gillespie, and Muhly [5] showed that X ∈ HT =⇒ X ∈ ACF. In this note, we will show that X ∈ ACF =⇒ X ∈ UMD, thus providing a new proof of Bourgain’s result X ∈ HT =⇒ X ∈ UMD.
Copper-catalyzed electrophilic amination of organozinc nucleophiles: documentation of O-benzoyl hydroxylamines as broadly useful R2N(+) and RHN(+) synthons.

This paper details new copper-catalyzed electrophilic amination reactions of diorganozinc reagents using O-benzoyl hydroxylamines as electrophilic nitrogen sources that may be accessed in one step. Simple and functionalized aryl, heteroaryl-, benzyl, n-alkyl, sec-alkyl, and tert-alkyl nucleophiles couple with R2NOC(O)Ph and RHNOC(O)Ph reagents in the presence of catalytic quantities of copper salts to provide tertiary and secondary amines, respectively, in generally good yields. In many cases, the product may be isolated analytically pure after a simple extractive workup. The amination process is shown to tolerate a significant degree of steric demand. The amination of nominally unreactive Caryl−H bonds via a sequential directed ortho metalation/transmetalation/catalytic amination reaction sequence is detailed. The direct Cu-catalyzed amination of Grignard reagents using cocatalysis by ZnCl2 is described.
Low-dimensional clustering detects incipient dominant influenza strain clusters

Influenza has been circulating in the human population and has caused three pandemics in the last century (1918 H1N1, 1957 H2N2 and 1968 H3N2). The 2009 A(H1N1) was classified by World Health Organization as the fourth pandemic. Influenza has a high evolution rate, which makes vaccine design challenging. We here consider an approach for early detection of new dominant strains. By clustering the 2009 A(H1N1) sequence data, we found two main clusters. We then define a metric to detect the emergence of dominant strains. We show on historical H3N2 data that this method is able to identify a cluster around an incipient dominant strain before it becomes dominant. For example, for H3N2 as of 30 March 2009, the method detects the cluster for the new A/British Columbia/RV1222/2009 strain. This strain detection tool would appear to be useful for annual influenza vaccine selection.
Evaluating Heuristics Used When Designing Product Costing Systems

The academic and practitioner literature justifies firms' use of product costs in product pricing and capacity planning decisions as heuristics to address an otherwise intractable problem. However, product costs are the output of a cost reporting system, which itself is the outcome of heuristic design choices. In particular, because of informational limitations, when designing cost systems firms use simple rules of thumb to group resources into cost pools and to select drivers used to allocate the pooled costs to products. Using simulations, we examine how popular choices in costing system design influence the error in reported costs. Taking information needs into account, we offer alternative ways to translate the vague guidance in the literature to implementable methods. Specifically, we compare size-based rules for forming cost pools with more informationally demanding correlation-based rules and develop a blended method that performs well in terms of accuracy. In addition, our analysis suggests that significant gains can be made from using a composite driver rather than selecting a driver based on the consumption pattern for the largest resource only, especially when combined with correlation-based rules to group resources. We vary properties of the underlying cost structure (such as the skewness in resource costs, the traceability of resources to products, the sharing of resources across products, and the variance in resource consumption patterns) to address the generalizability of our findings and to show when different heuristics might be preferred. This paper was accepted by Stefan Reichelstein, accounting.
Three models for the description of language

We investigate several conceptions of linguistic structure to determine whether or not they can provide simple and "revealing" grammars that generate all of the sentences of English and only these. We find that no finite-state Markov process that produces symbols with transition from state to state can serve as an English grammar. Furthermore, the particular subclass of such processes that produce n -order statistical approximations to English do not come closer, with increasing n , to matching the output of an English grammar. We formalize-the notions of "phrase structure" and show that this gives us a method for describing language which is essentially more powerful, though still representable as a rather elementary type of finite-state process. Nevertheless, it is successful only when limited to a small subset of simple sentences. We study the formal properties of a set of grammatical transformations that carry sentences with phrase structure into new sentences with derived phrase structure, showing that transformational grammars are processes of the same elementary type as phrase-structure grammars; that the grammar of English is materially simplified if phrase structure description is limited to a kernel of simple sentences from which all other sentences are constructed by repeated transformations; and that this view of linguistic structure gives a certain insight into the use and understanding of language.
Solving triangular linear systems in parallel using substitution

Working within the LogP model, we present parallel triangular solvers which use forward/backward substitution and show that they are optimal. We begin by deriving several lower bounds on execution time for solving triangular linear systems. Specifically, we derive lower bounds in which it is assumed that the number of data items per processor is bounded, a general lower bound, and lower bounds for specific data layouts commonly used for this problem. Furthermore, algorithms are provided which have running times within a constant factor of the lower bounds described. One interesting result is that the popular 2-dimensional block matrix layout necessarily results in significantly longer running times than simpler one-dimensional schemes. Finally, we present a generalization of the lower bounds to banded triangular linear systems.
Which Boolean functions are most informative

We introduce a simply stated conjecture regarding the maximum mutual information a Boolean function can reveal about noisy inputs. Specifically, let Xn be i.i.d. Bernoulli(l/2), and let Yn be the result of passing Xn through a memoryless binary symmetric channel with crossover probability α. For any Boolean function b : {0, l}n → {0,1}, we conjecture that I(b(Xn);Yn) ≤ 1 - H (α). While the conjecture remains open, we provide substantial evidence supporting its validity.
Spectral and graph-theoretic bounds on steady-state-probability estimation performance for an ergodic Markov chain

Abstract Motivated by the wide application of Markov-chain steady-state-probability estimation, we pursue a spectral and graph-theoretic performance analysis of a classical estimator for steady-state probabilities here. Specifically, we connect a performance measure to estimate the structure of the underlying graph defined on the Markov-chain's state transitions. To do so, (1) we present a series of upper bounds on the performance measure in terms of the subdominant eigenvalue of the state transition matrix, which is closely connected with the graph structure; (2) as an illustration of the graph-theoretic analysis, we then relate the subdominant eigenvalue to the connectivity of the graph, including for the strong-connectivity case and the weak-link case. We also apply the results to characterize estimation in Markov chains with rewards.
ScalaExtrap: Trace-based communication extrapolation for SPMD programs

Performance modeling for scientific applications is important for assessing potential application performance and systems procurement in high-performance computing (HPC). Recent progress on communication tracing opens up novel opportunities for communication modeling due to its lossless yet scalable trace collection. Estimating the impact of scaling on communication efficiency still remains nontrivial due to execution-time variations and exposure to hardware and software artifacts.This work contributes a fundamentally novel modeling scheme. We synthetically generate the application trace for large numbers of nodes via extrapolation from a set of smaller traces. We devise an innovative approach for topology extrapolation of single program, multiple data (SPMD) codes with stencil or mesh communication. Experimental results show that the extrapolated traces precisely reflect the communication behavior and the performance characteristics at the target scale for both strong and weak scaling applications. The extrapolated trace can subsequently be (a) replayed to assess communication requirements before porting an application, (b) transformed to autogenerate communication benchmarks for various target platforms, and (c) analyzed to detect communication inefficiencies and scalability limitations.To the best of our knowledge, rapidly obtaining the communication behavior of parallel applications at arbitrary scale with the availability of timed replay, yet without actual execution of the application, at this scale, is without precedence and has the potential to enable otherwise infeasible system simulation at the exascale level.