cssi/SciSciGPT-SciSciNet huggingface dataset:
A holistic approach to decentralized structural damage localization using wireless sensor networks

Wireless sensor networks (WSNs) have become an increasingly compelling platform for Structural Health Monitoring (SHM) applications, since they can be installed relatively inexpensively onto existing infrastructure. Existing approaches to SHM in WSNs typically address computing system issues or structural engineering techniques, but not both in conjunction. In this paper, we propose a holistic approach to SHM that integrates a decentralized computing architecture with the Damage Localization Assurance Criterion algorithm. In contrast to centralized approaches that require transporting large amounts of sensor data to a base station, our system pushes the execution of portions of the damage localization algorithm onto the sensor nodes, reducing communication costs by two orders of magnitude in exchange for moderate additional processing on each sensor. We present a prototype implementation of this system built using the TinyOS operating system running on the Intel Imote2 sensor network platform. Experiments conducted using two different physical structures demonstrate our system's ability to accurately localize structural damage. We also demonstrate that our decentralized approach reduces latency by 65.5% and energy consumption by 64.0% compared to a typical centralized solution.
Hazards of Expropriation: Tenure Insecurity and Investment in Rural China

This paper uses household data from Northeast China to examine the link between investment and land tenure insecurity induced by China’s system of village-level land reallocation. We quantify expropriation risk using a hazard analysis of individual plot tenures and incorporate the predicted “hazards of expropriation” into an empirical analysis of plot-level investment. Our focus is on organic fertilizer use, which has long lasting benefits for soil quality. Although we find that higher expropriation risk significantly reduces application of organic fertilizer, a welfare analysis shows that guaranteeing land tenure in this part of China would yield only minimal efficiency gains.
USING ARTIFICIAL NEURAL NETWORKS AND SELF-ORGANIZING MAPS FOR DETECTION OF AIRFRAME ICING

A method of using Artificial Neural Networks (ANNs) and Kohonen Self-Organizing Maps (SOMs) to detect ice on a horizontal tail is proposed and investigated. It is hypothesized that ANN systems trained on the aircraft dynamics would converge to different connection weights for iced and clean aircraft. Kohonen SOMs are used to detect these differences automatically and therefore identify the configuration as being clean or being iced. The system is shown to be capable of acting in an advisory role for the flight crew. The fidelity of the approach is shown to depend on the level of atmospheric turbulence, as well as the magnitude of the elevator input NOMENCLATURE Subscripts denote derivatives, unless stated otherwise. [A] state matrix [B] control matrix
Minichannels in Polymer Electrolyte Membrane Fuel Cells

This paper provides an overview of the application of minichannels, typically on the order of a 1 mm hydraulic diameter, in the design of polymer electrolyte membrane (PEM) fuel cells. In these ele...
Absence of Bowditch phenomenon in the ventricular muscle of hamsters with hereditary cardiomyopathy

Abstract The interval-tension relationship of right ventricular muscles of normal hamsters was compared to that of hamsters with hereditary cardiomyopathy, with or without congestive heart failure. The contractility of the heart of animals with cardiomyopathy without circulatory insufficiency did not differ from that of the normal animals at any frequency. The cardiac muscle of animals with severe congestive heart failure showed normal contractility at a low frequency of stimulation (range of the Woodworth phenomenon) but did not show the increased contractility upon high frequency stimulation (Bowditch phenomenon) seen in all other animals. Ryanodine, which eliminates only the contractility caused by the Woodworth phenomenon, abolished the contractility of the hearts of animals with congestive failure over the whole frequency range. Cardiac glycosides, which are known to potentiate the Bowditch phenomenon, were ineffective on the cardiac muscle of animals without Bowditch phenomenon. The probable cause of cardiac failure in hamsters with hereditary cardiomyopathy is discussed.
Cascading failures in networks with proximate dependent nodes

We study the mutual percolation of a system composed of two interdependent random regular networks. We introduce a notion of distance to explore the effects of the proximity of interdependent nodes on the cascade of failures after an initial attack. We find a nontrivial relation between the nature of the transition through which the networks disintegrate and the parameters of the system, which are the degree of the nodes and the maximum distance between interdependent nodes. We explain this relation by solving the problem analytically for the relevant set of cases. In the process, we solve a variant of R\'enyi's parking problem on treelike graphs.
Computer-mediated communication and cooperation in social dilemmas: an experimental analysis

One of the most consistent findings in experimental studies of social dilemmas is the positive influence of face-to-face communication on cooperation. The face-to-face `communication effect' has be...
Penetration of a Transverse Supersonic Jet into a Subsonic Compressible Crossflow

Particle image velocimetry data have been acquired in the far field of the interaction generated by an overexpanded axisymmetric supersonic jet exhausting transversely from a flat plate into a subsonic compressible crossflow. Mean velocity fields were found in the streamwise plane along the flowfield centerline for different values of the crossflow Mach number M∞ and the jet-to-freestream dynamic pressure ratio J. The magnitude of the streamwise velocity deficit and the vertical velocity component both decay with downstream distance and were observed to be greater for larger J while M∞ remained constant. Jet trajectories derived independently using the maxima of each of these two velocity components are not identical, but show increasing jet penetration for larger J. Similarity in the normalized velocity field was found for constant J at two different transonic M∞ ,b utat two lower M∞ the jet appeared to interact with the wall boundary layer and data did not collapse. The magnitude and width of the peak in the vertical velocity component both increase with J, suggesting that the strength and size of the counter-rotating vortex pair increase and, thus, may have a stronger influence on aerodynamic surfaces despite further jet penetration from the wall.
Linear phase cosine modulated maximally decimated filter banks with perfect reconstruction

We propose a novel way to design maximally decimated FIR cosine modulated filter banks, in which each analysis and synthesis filter has a linear phase. The system can be designed to have either the approximate reconstruction property (pseudo-QMF system) or perfect reconstruction property (PR system). In the PR case, the system is a paraunitary filter bank. As in earlier work on cosine modulated systems, all the analysis filters come from an FIR prototype filter. However, unlike in any of the previous designs, all but two of the analysis filters have a total bandwidth of 2/spl pi//M rather than /spl pi//M (where 2M is the number of channels in our notation). A simple interpretation is possible in terms of the complex (hypothetical) analytic signal corresponding to each bandpass subband. The coding gain of the new system is comparable with that of a traditional M-channel system (rather than a 2M-channel system). This is primarily because there are typically two bandpass filters with the same passband support. Correspondingly, the cost of the system (in terms of complexity of implementation) is also comparable with that of an M-channel system. We also demonstrate that very good attenuation characteristics can be obtained with the new system.
Chemistry on a single protein, vascular cell adhesion molecule-1, during forced unfolding.

Proteins of many types experience tensile forces in their normal function, and vascular cell adhesion molecule-1 (VCAM-1) is typical in this. VCAM has seven Ig domains, and each has a disulfide bond (-S–S-) buried in its core that covalently stabilizes about half of each domain against unfolding. VCAM is extended here by single molecule atomic force microscopy in the presence or absence of reducing agents. In the absence of reducing agent, a sawtooth pattern of forced unfolding reveals an average period and total length consistent with disulfide locations in VCAM. With increasing reducing agent, accessible disulfides are specifically reduced (to SH); the average period for unfolding increases up to saturation together with additional metrics of unfolding. Steered molecular dynamics simulations of unfolding indeed show that the core disulfide bond is solvent-exposed in the very earliest stages of protein extension. Michaelis-Menten kinetics emerge with reduction catalyzed by force (τreduction ∼ 10–4 s). The results establish single molecule reduction, one bond at a time, and show that mechanical forces can play a key role in modulating the redox state of cell adhesion proteins that are invariably stressed in cell adhesion.
Enantioselective organocatalytic intramolecular Diels-Alder reactions. The asymmetric synthesis of solanapyrone D.

The first direct enantioselective organocatalytic intramolecular Diels−Alder reaction has been accomplished. The use of iminium catalysis has provided a new catalytic strategy for the enantioselective [4 + 2] cycloisomerization of a wide variety of tethered diene-enal systems. The use of imidazolidinones 1 and 2 as the asymmetric catalysts has been found to mediate the enantioselective construction of [4.4.0] and [4.3.0] ring systems. Application of this methodology to the highly efficient asymmetric synthesis of the marine metabolite solanpyrone D has also been accomplished. A diverse spectrum of aldehyde substrates can also be accommodated in this new organocatalytic transformation. Importantly, this technology has been utilized to execute the first enantioselective, catalytic Type II IMDA reaction.
A generalized cut-set bound

In this paper, we generalize the well known cutset bound (see for example [1, p. 444]) to the problem of lossy transmission of functions of arbitrarily correlated sources over a discrete memoryless multiterminal network.
Compact vs. exponential-size LP relaxations

In this paper, we illustrate by means of examples a technique for formulating compact (i.e. polynomial-size) linear programming relaxations in place of exponential-size models requiring separation algorithms. In the same vein as a celebrated theorem by Grotschel, Lovasz and Schrijver, we state the equivalence of compact separation and compact optimization. Among the examples used to illustrate our technique, we introduce a new formulation for the traveling salesman problem, whose relaxation we show as an equivalent to the subtour elimination relaxation.
Coordinate-invariant path integral methods in conformal field theory

We present a coordinate-invariant approach, based on a Pauli–Villars measure, to the definition of the path integral in two-dimensional conformal field theory. We discuss some advantages of this approach compared to the operator formalism and alternative path integral approaches. We show that our path integral measure is invariant under conformal transformations and field reparametrizations, in contrast to the measure used in the Fujikawa calculation, and we show the agreement, despite different origins, of the conformal anomaly in the two approaches. The natural energy–momentum in the Pauli–Villars approach is a true coordinate-invariant tensor quantity, and we discuss its nontrivial relationship to the corresponding nontensor object arising in the operator formalism, thus providing a novel explanation within a path integral context for the anomalous Ward identities of the latter. We provide a direct calculation of the nontrivial contact terms arising in expectation values of certain energy–momentum products, and we use these to perform a simple consistency check confirming the validity of the change of variables formula for the path integral. Finally, we review the relationship between the conformal anomaly and the energy–momentum two-point functions in our formalism.
Placing the satellite in its orbit

The VANGUARD satellite launching vehicle is a three-stage rocket of which the first two stages are guided and the third stage is maintained in a fixed orientation while it is firing. The first stage, an improved Viking, serves primarily to raise the remaining stages to altitude. The second stage, another liquid-propellant rocket, contains the guidance for the three-stage vehicle and, in addition, supplies some of the propulsive energy. The third stage, a solid-propellant rocket, is ejected from the second stage at orbital altitude and provides about half of the required orbital velocity. The VANGUARD launching vehicle system was chosen from a number of possible two- and three-stage vehicle combinations. It represents the smallest satellite launching vehicle consistent with the present state of rocket development.
Detection of curved and straight segments from gray scale topography

Abstract Conventional structural pattern recognition methods that rely on thinning approximate the skeleton by polygons and proceed from that step to recognition. Polygonal approximations have the disadvantage that they introduce significant ambiguities. In particular, vertices may correspond either to real corners or to approximations of smooth arcs. We propose a method that relies on topographic features and, in particular, ridge lines. The information about ridge line directions obtained from the underlying surface of the gray tone is used to discriminate between arcs and straight lines. Normally, ridge lines are centered within character strokes, forming skeleton-like ribbons with generally no more than three pixels in width. For each ridge pixel, the tangent direction of the ridge line at the pixel is calculated. These computed tangent directions are then used in the detection of sharp corners and junctions, in the line tracking process, and in the feature decomposition process. Decomposition is achieved using curvature primitives and singular points. The result of the method is a relational feature graph which gives a compact and flexible description of the shapes of the objects in the input image. By not using a conventional thinning algorithm and performing arc and straight line decomposition without a usual polygonal approximation step, our method is able to reduce some artifacts of conventional thinning and to eliminate completely the ambiguities resulting from polygonal approximations.
Correlates and outcomes of preserved left ventricular systolic function among older adults hospitalized with heart failure.

Background Heart failure (HF) in older adults is often associated with preserved left ventricular systolic function (LVSF). The objective of this retrospective follow-up study was to determine the correlates and outcomes of preserved LVSF among older adults hospitalized with HF. Methods We studied older Medicare beneficiaries hospitalized with HF (n = 1091) who had documented LVSF evaluation (n = 438). LVSF was defined as preserved if left ventricular ejection fraction was ≥40%. The Fisher exact test and the Student t test were used to compare baseline characteristics between patients with preserved versus those with impaired LVSF. Multivariate logistic regression analysis was used to determine the correlates of preserved LVSF. Cox proportional hazards analyses were used to determine the associations between LVSF and both 4-year mortality rates and 6-month readmission rates and the associations between angiotensin-converting enzyme (ACE) inhibitor use and 4-year mortality rates, separately, in patients with preserved and impaired LVSF. Results Of the 438 patients, 200 (46%) had preserved LVSF. Women were more likely to have preserved LVSF (odds ratio [OR] = 2.44, 95% CI 1.57-3.81) than men. Preserved LVSF was associated with lower 4-year mortality rates (adjusted hazards ratio [HR] = 0.67, 95% CI 0.52-0.86) but not with 6-month readmission rates (adjusted HR = 0.66, 95% CI 0.41-1.09). The use of ACE inhibitors was associated with lower 4-year mortality rates in patients with impaired LVSF (adjusted HR = 0.61, 95% CI 0.43-0.86) but not in those with preserved LVSF (HR = 0.96, 95% CI 0.65-1.42). Conclusions Among older adults hospitalized with HF, preserved LVSF was common among women and was associated with significantly higher morbidity and mortality rates, which were unaffected by treatment with ACE inhibitors. (Am Heart J 2002;144:365-72.)
Changing phenotypes of hematopoietic stem cells.

Identification of the surface phenotypes of hematopoietic stem cells is an important subject in both clinical stem cell transplantation and basic research in hematopoiesis. Transplantation of pure populations of stem cells should eliminate the occurrence of graft-vs-host disease (GVHD) in allogeneic transplantation and may reduce the recurrence rate of malignancies in autologous transplantation. Availability of highly enriched populations of stem cells should facilitate investigations in a number of areas such as in vitro expansion, cryogenic storage, and gene therapy using stem cells. An ultimate goal is to develop a method to quantitate the number of living stem cells based on their surface characteristics. During the last two decades, investigators identified a number of surface molecules, which, in combinations, were thought to provide exact definition of murine and human stem cells. Recent studies of murine stem cells, however, clearly demonstrated that expression of the surface antigens of stem cells is under the influence of developmental stages and the kinetic state of the stem cells. This review summarizes the concept of the changing phenotypes of hematopoietic stem cells.
Single-Mode Panel Flutter of a Wind Tunnel Flex-Wall

Twice during the spring of 1978, the two steel-plate "flex-walls" that form the variable-geometry nozzle of the 11- by 11-ft transonic wind tunnel at Ames Research Center experienced a severe dynamic instability. Both walls fluttered in the fundamental beam-bending mode and experienced stresses approaching the yield strength of the material. Both flutter incidents occurred at Mach numbers of about 1.15. The tunnel, operational for 24 years, had no history of such an instability. The cause of these flutter incidents, the steps taken to prevent a recurrence, and the requalification of the facility are described.
Menstrual regulation and contraception in Bangladesh: Competing or complementary?

To examine the relationship between menstrual regulation (MR) and subsequent use of contraception in Bangladesh, we studied the birth control practices of a 6-month cohort of 4359 family-planning acceptors in a family-planning clinic in Dacca. We compared their use of birth control measures before and after MR. We attempted to examine the subsequent pregnancy and induced-abortion rates of 1671 of these women through a 3-year non-concurrent prospective study. Of those 1172 made their first visit to the clinic to obtain an MR and the remaining 499 women, who served as a comparison group, made their first visit to obtain contraceptive services not associated with MR. Three years' followup data were available for 558 women in the MR group and 228 women in the comparison group. Based on these data, the 3-year pregnancy rate for the MR group was 37.6/100 women and the induced abortion rate was 4.3/100 women. The 3-year pregnancy rate for the comparison group was 39/100 women and the induced abortion rate was 3.5/100 pregnancies. Thus, during a 3-year period women in the MR group did not obtain abortions significantly more often than women in the comparison group.
Analysis of random number generators using Monte Carlo simulation

Monte Carlo simulation is one of the main applications involving the use of random number generators. It is also one of the best methods of testing the randomness properties of such generators, by comparing results of simulations using different generators with each other, or with analytic results. Here we compare the performance of some popular random number generators by high precision Monte Carlo simulation of the 2-d Ising model, for which exact results are known, using the Metropolis, Swendsen-Wang, and Wolff Monte Carlo algorithms. Many widely used generators that perform well in standard statistical tests are shown to fail these Monte Carlo tests.
MAGPI (Meatoplasty and Glanuloplasty) A Procedure for Subcoronal Hypospadias

The MAGPI operation for the distal meatus has been a satisfactory operation both functionally and cosmetically. The complication rate is minimal. We therefore believe it is warranted in such cases, particularly to produce the esthetic appearance of a normal penis. We have found it to be a difficult operation to teach others except by demonstration, since we have not been very very successful in producing diagrams or photographs which convey the details of the technique adequately. It is therefore recommended that before this procedure is attempted, one should observe its performance by a surgeon who has mastered the technique.
Are economists human

A controversy among economists and others interested in the limits of rational choice analysis, still running after an onset at least two decades ago, concerns whether intelligent people and especially experts, can be subject to cognitive illusions. This note provides a striking illustration supporting that disconcerting conjecture. It analyses the apparent inability of professional economists to give a better than chance response to a very elementary question about consumer surplus.
Concise Total Synthesis of (+)-Gliocladins B and C.

The first total synthesis of (+)-gliocladin B is described. Our concise and enantioselective synthesis takes advantage of a new regioselective Friedel–Crafts-based strategy to provide an efficient multigram-scale access to the C3-(3′-indolyl)hexahydropyrroloindole substructure, a molecular foundation present in a significant subset of epipolythiodiketopiperazine natural alkaloids. Our first-generation solution to (+)-gliocladin B involved the stereoselective formation of (+)-12-deoxybionectin A, a plausible biosynthetic precursor. Our synthesis clarified the C15 stereochemistry of (+)-gliocladin B and allowed its full structure confirmation. Further studies of a versatile dihydroxylated diketopiperazine provided a concise and efficient synthesis of (+)-gliocladin B as well as access to (+)-gliocladin C.
The Hubble Constant from (CLASS) Gravitational Lenses

Received 2001 January 21, accepted 2001 April 5 One of the main objectives of the Cosmic Lens All-Sky Survey (CLASS) collaboration has been to find gravitational lens (GL) systems at radio wavelengths that are suitable for the determination of time delays between image pairs. The survey is now near completion and at least 18 GL systems have been found. Here, I will discuss our efforts to measure time delays from several of these systems with the ultimate aim of constraining the Hubble Constant (H0). Thus far three CLASS GL systems (B0218+357, B1600+434 and B1608+656) have yielded measurements of time delays, from which values of H0 ≈ 60–70 km s-1 Mpc-1 have been estimated. Although most GL systems give similar values of H0, statistical and systematic uncertainties are still considerable. To reduce these uncertainties, I will mention two monitoring programs that we are undertaking to (re)measure time delays in 14 CLASS GL systems and address several important issues for the near future.
Influence of Reclaimed Asphalt Pavement Temperature on Mix Design Process of Cold In-Place Recycling Using Foamed Asphalt

The temperature of the existing asphalt pavement, which is to be recycled, would change from a low morning temperature of the spring/fall season to a high afternoon temperature of summer. However, most agencies do not consider the temperature of the reclaimed asphalt pavement (RAP) materials when they design cold in-place recycling using foamed asphalt (CIR-foam) mixtures. The main objective of this research is to determine whether the temperature of RAP materials would affect the optimum foamed asphalt content (FAC), which would produce the highest wet indirect tensile strength. On the basis of the limited laboratory test results, the temperature of RAP materials would have a significant impact on the wet indirect tensile strength of CIR-foam mixtures. This research supports the field reduction of FAC up to 0.5% when the RAP temperature reaches up to 55°C. The change in the wet indirect tensile strength caused by RAP temperatures was not sufficient to warrant a design method change. Also, improved compac...
Asociaciones: una lectura de "Mephisto Waltzer"

En este trabajo se explora la estetica de la asociacion en el cuento "Mephisto Waltzer", en el cual se muestra con claridad la relacion que se establece en la narrativa de Sergio Pitol entre la cotidianidad enganosa y la fantasia literaria. Se abordan aqui los distintos componentes del juego de cajas chinas de "Mephisto Waltzer", haciendose hincapie en las alusiones, tanto internas como externas, a La sonata de Kreutzer de Leon Tolstoi. En "Mephisto Waltzer" Pitol ensaya con elegancia y economia uno de sus temas predilectos: la ambiguedad del arte.
Gender in Transition: The Case of North Korea

This paper uses a survey of 300 North Korean refugees to examine the experience of women in North Korea’s fitful economic transition. Like other socialist states, North Korea has maintained a de jure commitment to women’s rights. However, we find that women have been disproportionately shed from state-affiliated employment and thrust into a market environment characterized by weak institutions and corruption. As a result, the state and its affiliated institutions are increasingly populated by males, and the market, particularly in its retail aspects, is dominated by women. Among the most recent cohort of refugees to leave North Korea, more than one-third of male respondents indicate that criminality and corruption is the best way to make money, and 95 percent of female traders report paying bribes to avoid the penal system. In short, the increasingly male-dominated state preys on the increasingly female-dominated market. These results paint a picture of a vulnerable group that has been disadvantaged in North Korea’s transition. Energies are directed toward survival, mass civil disobedience is reactive, and as a group, this population appears to lack the tools or social capital to act collectively to improve their status.
A time- and memory-sharing executive program for quick-response on-line applications

The TX-2 Computer, an experimental facility at M.I.T. Lincoln Laboratory, has been in operation since 1960. Never a service facility, the computer has been used principally in a number of long-term research projects that have taken advantage of the special input/output capabilities and the direct accessibility of the machine. These projects have included graphics, waveform processing, and pattern recognition. Most of the work on the computer has involved real-time inputs, interaction with output displays, or both. The computer has always been used as an on-line facility with the bulk of its time allotted in sessions of several hours duration. Programming has been in machine language, augmented in the past by a number of personal macro languages and recently by a more general macro language for list processing (CORAL). An on-line macro assembler, MK 4, has been used both as an assembly program and on-line operating system by most users.
The influences of the material properties on ceramic micro-stereolithography

Abstract Ceramic micro-stereolithography (μSL) was recently introduced in the fabrication of complex 3D ceramic microstructures. Light scattering is found as an important factor in the μSL of ceramics. In this work, the Monte Carlo ray tracing method is employed to investigate the influences of the important materials properties on the scattering during the ceramic μSL. It is found that the scattering is the strongest when the size of the ceramic powders approaches to the laser wavelength (0.364 μm). It was also found that the higher the refractive index contrast between the particle and the resin, the stronger the light scattering. High laser intensity is required to fabricate absorbing ceramic materials to compensate for the laser energy absorbed by the ceramic particle. The μSL of three typical ceramic powders: silica, alumina, and lead zirconate titanate (PZT) are examined by the numerical model. The numerical model has been demonstrated as an efficient tool to optimize the μSL process. Finally, the ceramic micro green structures have been successfully fabricated.
Bilateral carcinoma of the temporal bone: case report and literature review.

Summary Introduction Squamous cell carcinoma of the temporal bone is a rare entity. Only a few cases have been reported in the literature and even fewer describe bilateral tumours. Because its clinical presentation resembles chronic otitis media or otitis externa, diagnosis could be delayed. Case Report A case is presented of bilateral squamous cell carcinoma of the temporal bone in a 66 year old woman. The patient underwent a left subtotal petrosectomy followed by a right subtotal petrosectomy a month later. Conclusions Early diagnosis is directly related to patient prognosis. However, prognosis remains poor and the surgical treatment is a challenge for the experienced skull base surgeon.
An algebra-level version of a link-polynomial identity of Lickorish

We establish isomorphisms between certain specializations of BMW algebras and the symmetric squares of Temperley-Lieb algebras. These isomorphisms imply a link-polynomial identity due to W. B. R. Lickorish. As an application, we compute the closed images of the irreducible braid group representations factoring over these specialized BMW algebras.
Olefin Metathesis by Supported Metal Oxide Catalysts

The literature of olefin metathesis by heterogeneous supported catalysts, both industrial-type supported metal oxides (ReOx/Al2O3, ReOx/(SiO2–Al2O3), MoOx/SiO2, MoOx/Al2O3, MoOx/(SiO2–Al2O3), WOx/SiO2, and WOx/(SiO2–Al2O3)) and supported organometallic complexes, is comprehensively reviewed. The focus of this Review is supported metal oxide catalysts, but the well-defined supported organometallic catalyst literature is also covered because such model catalysts have the potential to bridge heterogeneous and homogeneous olefin metathesis catalysis. The recent world shortage of small olefin feedstocks has created renewed interest in olefin metathesis as a route to synthesizing small olefins and is reflected in the recent growth of the patent literature. Despite the extensive application of supported metal oxides in industry for metathesis of small and large olefins, the molecular structures and oxidation states of the catalytic active sites, surface reaction intermediates, and reaction mechanisms of this imp...
Representation dependence in probabilistic inference

Non-deductive reasoning systems are often representation dependent: representing the same situation in two different ways may cause such a system to return two different answers. Some have viewed this as a significant problem. For example, the principle of maximum entropy has been subjected to much criticism due to its representation dependence. There has, however, been almost no work investigating representation dependence. In this paper, we formalize this notion and show that it is not a problem specific to maximum entropy. In fact, we show that any representation-independent probabilistic inference procedure that ignores irrelevant information is essentially entailment, in a precise sense. Moreover, we show that representation independence is incompatible with even a weak default assumption of independence. We then show that invariance under a restricted class of representation changes can form a reasonable compromise between representation independence and other desiderata, and provide a construction of a family of inference procedures that provides such restricted representation independence, using relative entropy.
LHC searches for non-chiral weakly charged multiplets

In this paper we consider vector representations of fermions in multiplets of SU(2)L with a lightest neutral state, a notable example of which is the wino LSP in anomaly-mediated models. Because of the expected small one-loop-level splitting between charged and neutral states, the path length in the detector is finite but short so the signature is distinctive but challenging. Our analysis determines the LHC reach of models with additional weakly charged vector-like matter using similar search strategies to existing studies of some specific models. Currently planned search strategies would fail to find such particles, although early LHC data could be used to better understand our signal and possible backgrounds.
Linear and nonlinear associative memories for parameter estimation

This paper proposes the use of associative memories for obtaining preliminary parameter estimates for nonlinear systems. For each parameter vector r, in a selected training set, the system equations are used to determine a vector s, of system outputs, An associative memory matrix M is then constructed which optimally, in the least squares sense, associates each system output vector s, with its corresponding parameter vector I-,. Given any observed system output vector s*, an estimate i for the system parameters is obtained by setting i = Ms*. Numerical experiments are reported which indicate the effectiveness of this approach, especially for the nonlinear associative memory case in which the training vectors s, include not only the system output levels but also products of these levels. Training with noisy output vectors is shown to improve the accuracy of the parameter estimates when the
Increasing river discharge in the Eurasian Arctic: Consideration of dams, permafrost thaw, and fires as potential agents of change

[1] Discharge from Eurasian rivers to the Arctic Ocean has increased significantly in recent decades, but the reason for this trend remains unclear. Increased net atmospheric moisture transport from lower to higher latitudes in a warming climate has been identified as one potential mechanism. However, uncertainty associated with estimates of precipitation in the Arctic makes it difficult to confirm whether or not this mechanism is responsible for the change in discharge. Three alternative mechanisms are dam construction and operation, permafrost thaw, and increasing forest fires. Here we evaluate the potential influence of these three mechanisms on changes in discharge from the six largest Eurasian Arctic rivers (Yenisey, Ob’, Lena, Kolyma, Pechora, and Severnaya Dvina) between 1936 and 1999. Comprehensive discharge records made it possible to evaluate the influence of dams directly. Data on permafrost thaw and fires in the watersheds of the Eurasian Arctic rivers are more limited. We therefore use a combination of data and modeling scenarios to explore the potential of these two mechanisms as drivers of increasing discharge. Dams have dramatically altered the seasonality of discharge but are not responsible for increases in annual values. Both thawing of permafrost and increased fires may have contributed to changes in discharge, but neither can be considered a major driver. Cumulative thaw depths required to produce the observed increases in discharge are unreasonable: Even if all of the water from thawing permafrost were converted to discharge, a minimum of 4 m thawed evenly across the combined permafrost area of the six major Eurasian Arctic watersheds would have been required. Similarly, sensitivity analysis shows that the increases in fires that would have been necessary to drive the changes in discharge are unrealistic. Of the potential drivers considered here, increasing northward transport of moisture as a result of global warming remains the most viable explanation for the observed increases in Eurasian Arctic river discharge. INDEX TERMS: 1655 Global Change: Water cycles (1836); 1803 Hydrology: Anthropogenic effects; 1833 Hydrology: Hydroclimatology; 1860 Hydrology: Runoff and streamflow; KEYWORDS: Arctic river discharge, global change Citation: McClelland, J. W., R. M. Holmes, B. J. Peterson, and M. Stieglitz (2004), Increasing river discharge in the Eurasian Arctic: Consideration of dams, permafrost thaw, and fires as potential agents of change, J. Geophys. Res., 109, D18102,
Rational Pessimism, Rational Exuberance, and Asset Pricing Models

The paper estimates and examines the empirical plausibiltiy of asset pricing models that attempt to explain features of financial markets such as the size of the equity premium and the volatility of the stock market. In one model, the long run risks model of Bansal and Yaron (2004), low frequency movements and time varying uncertainty in aggregate consumption growth are the key channels for understanding asset prices. In another, as typified by Campbell and Cochrane (1999), habit formation, which generates time-varying risk-aversion and consequently time-variation in risk-premia, is the key channel. These models are fitted to data using simulation estimators. Both models are found to fit the data equally well at conventional significance levels, and they can track quite closely a new measure of realized annual volatility. Further scrutiny using a rich array of diagnostics suggests that the long run risk model is preferred.
Analysis of Orthogonal Matching Pursuit Using the Restricted Isometry Property

Orthogonal matching pursuit (OMP) is the canonical greedy algorithm for sparse approximation. In this paper we demonstrate that the restricted isometry property (RIP) can be used for a very straightforward analysis of OMP. Our main conclusion is that the RIP of order K+1 (with isometry constant δ <; [ 1/( 3√K)]) is sufficient for OMP to exactly recover any K-sparse signal. The analysis relies on simple and intuitive observations about OMP and matrices which satisfy the RIP. For restricted classes of K-sparse signals (those that are highly compressible), a relaxed bound on the isometry constant is also established. A deeper understanding of OMP may benefit the analysis of greedy algorithms in general. To demonstrate this, we also briefly revisit the analysis of the regularized OMP (ROMP) algorithm.
Synthesis and in vitro evaluation of N,N′-diphenyl and N-naphthyl-N′-phenylguanidines as N-methyl-d-aspartate receptor ion-channel ligands

Abstract A series of N,N ′-diphenyl and N -naphthyl- N ′-phenyl guanidine derivatives was synthesized as potential N -methyl- d -aspartate (NMDA) receptor positron emission tomography (PET) ligands. The affinity of the different compounds was determined using in vitro receptor binding assays, and their log P values were estimated using HPLC analysis. The effect of N′-3 and N′-3,5 substitution on affinity and lipophilicity was examined. The K i values ranged from 1.87 to 839 nM, while log P values between 1.22 and 2.88 were observed.
Search for supersymmetric particles at CDF

Abstract Analyses of events with large unbalanced transverse energy from the 1987 and 1988–1989 CDF data runs have set limits on the masses of supersymmetric squarks and gluinos. In a simple model with a stable photino as the lightest supersymmetric particle, the 1987 data with an integrated luminosity of 25.3 ng−1 have excluded at the 90% CL, squarks of mass less than 73 GeV/c2 and gluinos of mass less than 74 GeV/c2. Preliminary results from an analysis of 1 pb−1 of data from the current 1988–1989 run imply that the existence of a squark of mass less than 150 GeV/c2 is unlikely.
Colour appearance and compensation in the near periphery

The spectral sensitivity of the visual system varies markedly between the fovea and surrounding periphery owing in part to the rapid fall in macular pigment density with eccentricity. We examined how colour appearance changes between the fovea and near periphery (8°) by measuring achromatic loci and the loci of unique and binary hues. Chosen colours remained much more similar at the two locations than predicted by the change in spectral sensitivity. Compensation for white may reflect long-term gain changes within the cones that equate sensitivity for the local average stimulus in the fovea and periphery. However, adjusting only to the average stimulus cannot correct for all of the effects of a spectral sensitivity change, and predicts differences in colour percepts between the fovea and periphery that were not observed. The similarities in hue percepts at 0 and 8° thus suggest that additional processes help compensate colour appearance to maintain constancy in the near periphery. We model the results of previous studies to show that similar adjustments are implied by age-related changes in lens pigment, and to show that these adjustments are consistent with previous measurements of peripheral colour appearance based on hue cancellation.
Intersection homology with field coefficients: $K$-Witt spaces and $K$-Witt bordism

We construct geometric examples of pseudomanifolds that satisfy the Witt condition for intersection homology Poincare duality with respect to certain fields but not others. We then compute the bordism theory of K-Witt spaces for an arbitrary field K, extending results of Siegel for K = ℚ. © 2008 Wiley Periodicals, Inc.
Fault mode single-phase operation of a variable frequency induction motor drive and improvement of pulsating torque characteristics

Improved reliability and fault tolerant operation of power converter systems are extremely important for industrial AC drives. The paper considers variable frequency variable voltage operation of a three-phase induction motor in single-phase mode for two common faults of a three-phase inverter, i.e., open base drive and device short-circuit. The motor performance has been extensively analyzed in single-phase mode and remedial strategies have been developed to neutralize large second and other lower order harmonic pulsating torques. In a single-phase open loop volts/Hz control made of a faulty three-phase inverter, it has been demonstrated that odd harmonic voltages at appropriate phase angles can be injected to neutralize the low frequency pulsating torques so as to permit smooth drive operation. It has been shown that the pulsating torque can be further reduced by load dependent flux programming rather than operating with constant rated flux. >
Investigation of Electrokinetic Decontamination of Concrete

Abstract Experiments have been conducted to investigate the capabilities of electrokinetic decontamination of conceret. Batch equilibration studies have determined that the loading of cesium and strontium on concrete may be decreased using electrolyte solutions containing competing cations, while solubilization of uranium and cobalt, that precipitate at high pH, will require lixiviants containing complexing agents. Dynamic electrokinetic experiments showed greater mobility of cesium than strontium, while some positive results were obtained for the transport of cobalt through concrete using EDTA and for uranium using carbonate. *Managed by Lockheed Martin Energy Research Corp. for the U. S. Department of Energy under contract DE-AC05-96OR22464.
The point of view of the particle on the law of large numbers for random walks in a mixing random environment

The point of view of the particle is an approach that has proven very powerful in the study of many models of random motions in random media. We provide a new use of this approach to prove the law of large numbers in the case of one or higher-dimensional, finite range, transient random walks in mixing random environments. One of the advantages of this method over what has been used so far is that it is not restricted to i.i.d. environments.
THE SIZE, DENSITY, AND FORMATION OF THE ORCUS-VANTH SYSTEM IN THE KUIPER BELT

The Kuiper Belt object (KBO) Orcus and its satellite Vanth form an unusual system in the Kuiper Belt. While most large KBOs have small satellites in circular orbits and smaller KBOs and their satellites tend to be much closer in size, Orcus sits in between these two regimes. Orcus is among the largest objects known in the Kuiper Belt, but the relative size of Vanth is much larger than that of the tiny satellites of the other large objects. Here, we characterize the physical and orbital characteristics of the Orcus-Vanth system in an attempt to distinguish discuss possible formation scenarios. From Hubble Space Telescope observations, we find that Orcus and Vanth have different visible colors and that Vanth does not share the water ice absorption feature seen in the infrared spectrum of Orcus. We also find that Vanth has a nearly face-on circular orbit with a period of 9.5393 ± 0.0001 days and semimajor axis of 8980 ± 20 km, implying a system mass of (6.32 ± 0.01) × 10^(20) kg or 3.8% the mass of dwarf planet Eris. From Spitzer Space Telescope observations, we find that the thermal emission is consistent with a single body with diameter 940 ± 70 km and a geometric albedo of 0.28 ± 0.04. Assuming equal densities and albedos, this measurement implies sizes of Orcus and Vanth of 900 and 280 km, respectively, and a mass ratio of 33. Assuming a factor of 2 lower albedo for the non-icy Vanth, however, implies sizes of 860 km and 380 km and a mass ratio of 12. The measured density depends on the assumed albedo ratio of the two objects but is approximately 1.5 ± 0.3 g cm^(–3), midway between typical densities measured for larger and smaller objects. The orbit and mass ratio is consistent with formation from a giant impact and subsequent outward tidal evolution, and even consistent with the system having now achieved a double synchronous state. Because of the large angle between the plane of the heliocentric orbit of Orcus and the plane of the orbit of Vanth, the system can be equally well explained, however, by initial eccentric capture, Kozai cycling to increase the eccentricity and decrease the pericenter of the orbit of Vanth, and subsequent inward tidal evolution. We discuss implications of these formation mechanisms.
Performance Evaluation Of Image Intensifiers Coupled With Photofluorographic Camera And Their Clinical Application

Through measurements of modulation transfer functions (MTF), the imaging characteristics of three x-ray image intensifiers equipped with dissimilar input face designs coupled with photoflouorographic cameras were evaluated in the clinical environment. The MTF data enabled one to correlate and compare the clinical impressions of these imaging systems in a quantitative manner to evaluate and determine the feasibility of utilizing these imaging systems for different clinical approaches.
Rural vehicles in China: appropriate policy for appropriate technology

Over 3 million Chinese Rural Vehicles (CRVs) were produced in China in 2002, three times that of conventional passenger cars. Yet these smaller, simpler, indigenous vehicles are virtually unknown outside China. The CRV industry is unusual in that it evolved largely outside the control of government regulation and policy, using local technology and resources. CRVs now consume one fourth of the diesel fuel in China and play an important role in rural development. This paper is the first comprehensive assessment (in English or Chinese) of these vehicles and this remarkable industry. This study documents and analyzes vehicle technology, government policy, environmental impacts, market demand, and industry dynamics. We find that increasing government regulation (mostly for emissions and safety) is having profound effects on the industry, with uncertain implications for the sales and globalization of rural vehicle technology.