cssi/SciSciGPT-SciSciNet huggingface dataset:
Multiple Controls on Petroleum Biodegradation and Impact on Oil Quality

Biodegradation of oils in nature is important in reservoirs cooler than approximately 80°C. Oils from shallower, cooler reservoirs tend to be progressively more biodegraded than those in deeper, hotter reservoirs. Increasing levels of biodegradation generally cause a decline in oil quality, diminishing the producibility and value of the oil as API gravity and distillate yields decrease; in addition, viscosity, sulfur, asphaltene, metals, vacuum residua, and total acid numbers increase. For a specific hydrocarbon system (similar source type and level of maturity), general trends exist for oil-quality parameters vs. present-day reservoir temperatures of <80°C. However, other controls on biodegradation may also have significant effects, making predrill prediction of oil quality difficult in some areas. It has long been observed that fresh, oxygenated waters in contact with reservoir oil can cause extensive aerobic biodegradation. More recently, it has been recognized that anaerobic sulfatereducing and fermenting bacteria also can degrade petroleum. Highly saline formation waters may inhibit bacterial degradation and effectively shield oils from oil-quality deterioration. The timing of hydrocarbon charge(s) and the post-charge temperature history of the reservoir can have major effects on oil quality. Reservoirs undergoing current charging with hydrocarbons may overwhelm the ability of bacteria to degrade the oil, resulting in better-than-anticipated oil quality. Fresh charge to reservoirs containing previously degraded oil will upgrade oil quality. Calibrated methods of oil-quality risking, based on a detailed evaluation of reservoir charge and temperature history and local controls on biodegradation, need to be developed on a play and prospect basis.
Anchored metal nanoparticles: Effects of support and size on their energy, sintering resistance and reactivity

Many catalysts consist of metal nanoparticles anchored to the surfaces of oxide supports. These are key elements in technologies for the clean production and use of fuels and chemicals. We show here that the chemical reactivity of the surface metal atoms on these nanoparticles is closely related to their chemical potential: the higher their chemical potential, the more strongly they bond to small adsorbates. Controlling their chemical potential by tuning the structural details of the material can thus be used to tune their reactivity. As their chemical potential increases, this also makes the metal surface less noble, effectively pushing its behavior upwards and to the left in the periodic table. Also, when the metal atoms are in a nanoparticle with higher chemical potential, they experience a larger thermodynamic driving force to sinter. Calorimetric measurements of metal vapor adsorption energies onto clean oxide surfaces in ultrahigh vacuum show that the chemical potential increases with decreasing particle size below 6 nm, and, for a given size, decreases with the adhesion energy between the metal and its support, Eadh. The structural factors that control the metal/oxide adhesion energy are thus also keys for tuning catalytic performance. For a given oxide, Eadh increases with (ΔHsub,M − ΔHf,MOx)/ΩM2/3 for the metal, where ΔHsub,M is its heat of sublimation, ΔHf,MOx is the standard heat of formation of that metal's most stable oxide (per mole of metal), and ΩM is the atomic volume of the bulk solid metal. The value ΔHsub,M − ΔHf,MOx equals the heat of formation of that metal's oxide from a gaseous metal atom plus O2(g), so it reflects the strength of the chemical bonds which that metal atom can make to oxygen, and ΩM2/3 simply normalizes this energy to the area per metal atom, since Eadh is the adhesion energy per unit area. For a given metal, Eadh to different clean oxide surfaces increases as: MgO(100) ≈ TiO2(110) ≤ α-Al2O3(0001) < CeO2−x(111) ≤ Fe3O4(111). Oxygen vacancies also increase Eadh, but surface hydroxyl groups appear to decrease Eadh, even though they increase the initial heat of metal adsorption.
Agent-Based Computational Economics: A Brief Guide to the Literature

A principal concern of ACE researchers is to understand the ap-parently spontaneous formation of global regularities in economic processes, such as the unplannedcoordination of trading activities in decentralized market economies that economists associate withAdam Smith's invisible hand. The challenge is to explain how these global regularities arise fromthe bottom up, through the repeated local interactions of autonomous agents channeled throughsocioeconomic institutions, rather than from the top-down imposition of ¯ctitious coordinationmechanisms such as market clearing constraints or an assumption of single representative agents.The study of evolutionary economics is by no means new, of course. Even before Darwin,attempts were made to apply evolutionary ideas to socioeconomic behavior.Although this early work is now largely ignored by economists, economic textbooks still typicallyinclude at least some mention of the ideas of J. Schumpeter regarding the evolution of economicinstitutions. Moreover, Schumpeter's work, together with the seminal work by A. A. Alchian onuncertainty and evolution in economic systems, appears to have strongly in°uenced the subsequentwell-known work by R. Nelson, S. Winter and various of their collaborators on evolutionary theoriesof economic change. In addition, one has the work of W. B. Arthur on economies incorporatingpositive feedbacks, the work by Richard Day on dynamic economies characterized by complex phasetransitions, the work by J. Foster on an evolutionary approach to macroeconomics, R. Heiner's work
A 3D microfluidic device fabrication method using thermopress bonding with multiple layers of polystyrene film

In this article, we present a fabrication method that is capable of making (3D) microfluidic devices with multiple layers of homogeneous polystyrene (PS) film. PS film was chosen as the primary device material because of its advantageous features for microfluidics applications. Thermopress is used as a bonding method because it provides sufficient bonding strength while requiring no heterogeneous bonding materials. By aligning and sequentially stacking multiple layers (3 to 20) of patterned PS film that were achieved by a craft cutter, complicated 3D structured microfluidic devices can be fabricated by multiple steps of thermopress bonding. The smallest feature that can be achieved with this method is approximately 100 μm, which is limited by the resolution of the cutter (25 μm) as well as the thickness of the PS films. Bonding characteristics of PS films are provided in this article, including a PS film bonding strength test, bonding precision assessment, and PS surface wettability manipulation. To demonstrate the capability of this method, the design, fabrication, and testing results of a 3D interacting L-shaped passive mixer are presented.
R-PARITY VIOLATING U(1)′-EXTENDED SUPERSYMMETRIC STANDARD MODEL

Supersymmetry is one of the best motivated new physics scenarios. To build a realistic supersymmetric standard model, however, a companion symmetry is necessary to address various issues. While R-parity is a popular candidate that can address the proton and dark matter issues simultaneously, it is not the only option for such a property. We review how a TeV scale U(1)′ gauge symmetry can replace the R-parity. Discrete symmetries of the U(1)′ can make the model still viable and attractive with distinguishable phenomenology. For instance, with a residual discrete symmetry of the U(1)′, Z6 = B3 × U2, the proton can be protected by the baryon triality (B3) and a hidden sector dark matter candidate can be protected by the U-parity (U2).
Optimal adaptive control: A multivariate model for marketing applications

Marketing applications motivate a specialized model and its adaptive control. Each of r control variables is set in each of a sequence of time periods. The process being controlled has a response (profit) function that is the sum of a constant plus linear and quadratic forms in the control variables. The coefficients of the quadratic form are assumed to be known constants, those of the linear form to change with time as first-order autoregressive processes. Information about the changing coefficients is collected by performing a 2rfactorial experiment on a subportion of the process being controlled. Provision is made for adding further information from unspecified sources. Bayesian methods update the distributions of the unknown coefficients. Dynamic programming determines the values of the control variables and experimental design parameters to maximize the sum of discounted future profits. The probabilistic assumptions of the model are chosen so that all distributions are normal with known variances and, for the most part, zero covariances between variables. Partly as a result of this, optimal control turns out to involve rather simple exponential smoothing rules.
Feature-based crystal construction in computer-aided nano-design

Providing nanoengineers and scientists efficient and easy-to-use tools to create geometry conformations that have minimum energies is highly desirable in materials design. Recently we developed a periodic surface model to assist the construction of nanostructures parametrically for computer-aided nano-design. In this paper, we present a feature-based approach for crystal construction. The proposed approach creates models of basic features with the aid of periodic surfaces followed by operations between basic features. The goal is to introduce a rapid construction method for complex crystal structures.
Deeds that Help and Words that Hurt: Helping and Gossip as Moderators of the Relationship Between Leader–Member Exchange and Advice Network Centrality

We examine the relationship between leader–member exchange (LMX) quality and advice network centrality using multisource data from a sample of 250 retail employees and their respective managers in Turkey to test our hypothesized model of value and costs of being sought out for advice. Drawing upon the tenets of network generation theory (Nebus, 2006), we predict that the tendency of focal actors to help others and their own tendency to gossip would be behavioral moderators of the relationship between LMX quality and their advice network centrality. Consistent with network generation theory, our results reveal that LMX quality is positively related to centrality only for those actors with a high tendency to help coworkers and a low tendency to gossip about coworkers, suggesting that behaviors indicating helpfulness and discretion are necessary for high LMX members to maintain a central position in their work group's advice network. Implications and future research directions are discussed.
Polyploidy and Agriculture: Summary

As an outsider to this field with modest understanding of Polyploidy and its implications to agriculture, there is little that I can add to the discussion. The contributions which compose this session on the relevance of Polyploidy to agriculture have provided a wealth of information on a broad array of subjects ranging from the relation between Polyploidy and plant domestication to the very elegant uses of a unique series of aneuploids in wheat. There have been several striking conclusions and observations made by the various contributors some of which deserve special notice.
Signaling for decentralized routing in a queueing network

A discrete-time decentralized routing problem in a service system consisting of two service stations and two controllers is investigated. Each controller is affiliated with one station. Each station has an infinite size buffer. Exogenous customer arrivals at each station occur with rate $$\uplambda $$ . Service times at each station have rate $$\mu $$ . At any time, a controller can route one of the customers waiting in its own station to the other station. Each controller knows perfectly the queue length in its own station and observes the exogenous arrivals to its own station as well as the arrivals of customers sent from the other station. At the beginning, each controller has a probability mass function (PMF) on the number of customers in the other station. These PMFs are common knowledge between the two controllers. At each time a holding cost is incurred at each station due to the customers waiting at that station. The objective is to determine routing policies for the two controllers that minimize either the total expected holding cost over a finite horizon or the average cost per unit time over an infinite horizon. In this problem there is implicit communication between the two controllers; whenever a controller decides to send or not to send a customer from its own station to the other station it communicates information about its queue length to the other station. This implicit communication through control actions is referred to as signaling in decentralized control. Signaling results in complex communication and decision problems. In spite of the complexity of signaling involved, it is shown that an optimal signaling strategy is described by a threshold policy which depends on the common information between the two controllers; this threshold policy is explicitly determined.
Selection of near-minimum time geometric paths for robotic manipulators

A number of trajectory planning algorithms exist for calculating the joint positions, velocities, and torques which will drive a robotic manipulator along a given geometric path in minimum time. However, the time depends upon the geometric path, so the traversal time of the path should be considered again for geometric planning. There are algorithms available for finding minimum distance paths, but even when obstacle avoidance is not an issue, minimum (Cartesian) distance is not necessarily equivalent to minimum time. In this paper, we have derived a lower bound on the time required to move a manipulator from one point to another, and determined the form of the path which minimizes this lower bound. As numerical examples, we have applied the path solution to the first three joints of the Bendix PACS arm and the Stanford arm. These examples do indeed demonstrate that the derived approximate solutions usually require less time than Cartesian straight-line (minimum-distance) paths and joint-interpolated paths.
Microtubules in Dendritic Spine Development and Plasticity.

Recent studies indicate that microtubules (MTs) may play an important role in spine development and dynam- ics. Several imaging studies have now documented the exploration of dendritic spines by dynamic MTs in an activity- dependent manner. Furthermore, it was found that alterations of MT dynamics by pharmacological and molecular ap- proaches exert profound influence on the development and plasticity of spines associated with neuronal activity. It is rea- sonable to speculate that dynamic MTs may be responsible for targeted delivery of specific cargos to a selected number of spines and/or for interacting with the actin cytoskeleton to generate the structural changes of spines associated with synap- tic modifications.
A step towards the Alekseevskii conjecture

We refine existing structure results for non-compact, homogeneous, Einstein manifolds and provide a reduction in the classification problem of such spaces. Using this work, we verify the (Generalized) Alekseevskii conjecture for a large class of homogeneous spaces.
Pd(II)-catalyzed para-selective C-H arylation of monosubstituted arenes.

Pd-catalyzed highly para-selective C–H arylation of monosubstituted arenes (including toluene) is developed for the first time using an F+ reagent as a bystanding oxidant. This finding provides a new retrosynthetic disconnection for para-substituted biaryl synthesis via C–H/C–H cross-coupling.
Process map for plasma sprayed aluminum oxide-carbon nanotube nanocomposite coatings

Process map has been developed for plasma sprayed aluminum oxide (Al2O3) ceramic nanocomposite coatings with carbon nanotube (CNT) reinforcement in varying content and spatial distribution. The process map was constructed using the temperature and velocity data of the in-flight powder particles exiting from the plasma plume. Process map elucidates the interdependence of powder feedstock pre-treatment, CNTcontent and dispersion behavior on the in-flight particle thermal history and subsequently evolving microstructure and coating properties. High thermal conductivity of CNTs alters the heat transfer characteristic during the splat formation. Microstructure of the coatings consists of fully melted zone (FM), partially melted or solid-state sintered zone (PM) and porosity. Process map provides a processing control tool for plasma spraying of Al2O3–CNT nanocomposite coatings. © 2008 Elsevier B.V. All rights reserved.
Phase diagram, extended domain walls, and soft collective modes in a three-component fermionic superfluid

We study the phase diagram of a three-component Fermi gas with weak attractive interactions, which shows three superfluid and one normal phases. At weak symmetry breaking between the components the existence of domain walls interpolating between two superfluids introduces a new length scale much larger than the coherence length of each superfluid. This, in particular, limits the applicability of the local density approximation in the trapped case, which we also discuss. In the same regime the system hosts soft collective modes with a mass much smaller than the energy gaps of individual superfluids. We derive their dispersion relations at zero and finite temperatures and demonstrate that their presence leads to a significant enhancement of fluctuations near the superfluid-normal transitions.
The expansion of the south-western fisheries in late medieval England'

S outh-western England, particularly the counties of Devon and Cornwall, experienced significant economic growth during the late middle ages, as indicated in the leap in assessed wealth made by these counties between the early fourteenth century and the early sixteenth.2 To explain this prosperity, historians have pointed to south-western England's highly diversified economy, which allowed it to adjust to the crises of the late middle ages with less difficulty than most other regions. Although we are relatively well informed about the region's growing manufacture of cloth for export, its rising profits from tin mining, and its lucrative shift to livestock husbandry,3 less is known about developments in the region's maritime sector, and almost nothing about its marine fisheries, one of the mainstays of the maritime economy. This article explores the expansion of the region's sea fisheries from the late fourteenth century to the early sixteenth, and argues that this expansion was part of the maritime sector's critical, but unappreciated, contribution to the rising prosperity of south-western England during the late middle ages. Marine biologists even today point to the unusual richness and variety of fish species off the coasts of southern Cornwall and Devon, a bounty due in large part to their location at the boundary between the shallow turbid waters of the English and Bristol Channels and the unrestricted and deeper waters of the open sea to the west.4 In the middle ages, fishing provided a crucial source of income to residents of coastal villages and towns in the region. The labour services of several villeins in the manor of Stokenham in south Devon, for example, required three teams of nine villeins each-from February to early April-to station themselves by rocks on the seashore to watch for schools of fish (especially mullet), ready with their own boats and tackle to put out to sea. The lord of the
Minimum-energy multicast in wireless ad hoc networks with adaptive antennas: MILP formulations and heuristic algorithms

In this paper, we consider wireless ad hoc networks that use adaptive antennas and have limited energy resources. To explore the advantages of power saving offered by the use of adaptive antennas, we consider the case of source initiated multicast traffic. We present a constraint formulation for the MEM (Minimum-Energy Multicast) problem in terms of MILP (Mixed Integer Linear Programming) for wireless ad hoc networks. An optimal solution to the MEM problem using our MILP model can always be obtained in a timely manner for moderately sized networks. In addition to the theoretical effort, we also present two polynomial-time heuristic algorithms called RB-MIDP and D-MIDP to handle larger networks for which the MILP model may not be computationally efficient. The experimental results show that our algorithms compare well with other proposals discussed in this paper.
The Lagrange inversion theorem in the smooth case

The classical Lagrange inversion theorem is a concrete, explicit form of the implicit function theorem for real analytic functions. An explicit construction shows that the formula is not true for all merely smooth functions. The authors modify the Lagrange formula by replacing the smooth function by its Maclaurin polynomials. The resulting modified Lagrange series is, in analogy to the Maclaurin polynomials, an approximation to the solution function accurate to o(xN) as x→0.
Real-time part position sensing

A light-stripe vision system is used to measure the location of polyhedral features of parts from a single frame of video camera output. The geometric conditions which assure location of the feature when the light plane intersects three of the feature's faces are given. Issues such as accuracy in locating the line segments of intersection in the image and combining redundant information from multiple measurements and multiple sources are addressed. It was found that in 2.5 s, the prototype sensor was capable of locating a 2-in cube to an accuracy (one standard deviation) of 0.002 in (0.055 mm) in translation and 0.1 degrees (0.0015 radians) in rotation. When integrated with a manipulator, the system was capable of performing high-precision assembly tasks. >
On the existence of values of arbitration games

Two-person games in normal form are considered, where the players may use correlated strategies and where the problem arises, which Pareto optimal point in the payoff region to choose. We suppose that the players solve this problem with the aid of an arbitration function, which is continuous and profitable, and for which the inverse image of each Pareto point is a convex set. Then the existence of values and defensive e-optimal strategies is discussed. Existence theorems are derived, using families of suitable dummy zero-sum games. The derived existence theorems contain all known existence results as special cases.
The Long-Time Dynamics of Two Hydrodynamically-Coupled Swimming Cells

Swimming microorganisms such as bacteria or spermatozoa are typically found in dense suspensions, and exhibit collective modes of locomotion qualitatively different from that displayed by isolated cells. In the dilute limit where fluid-mediated interactions can be treated rigorously, the long-time hydrodynamics of a collection of cells result from interactions with many other cells, and as such typically eludes an analytical approach. Here, we consider the only case where such problem can be treated rigorously analytically, namely when the cells have spatially confined trajectories, such as the spermatozoa of some marine invertebrates. We consider two spherical cells swimming, when isolated, with arbitrary circular trajectories, and derive the long-time kinematics of their relative locomotion. We show that in the dilute limit where the cells are much further away than their size, and the size of their circular motion, a separation of time scale occurs between a fast (intrinsic) swimming time, and a slow time where hydrodynamic interactions lead to change in the relative position and orientation of the swimmers. We perform a multiple-scale analysis and derive the effective dynamical system—of dimension two—describing the long-time behavior of the pair of cells. We show that the system displays one type of equilibrium, and two types of rotational equilibrium, all of which are found to be unstable. A detailed mathematical analysis of the dynamical systems further allows us to show that only two cell-cell behaviors are possible in the limit of t→∞, either the cells are attracted to each other (possibly monotonically), or they are repelled (possibly monotonically as well), which we confirm with numerical computations. Our analysis shows therefore that, even in the dilute limit, hydrodynamic interactions lead to new modes of cell-cell locomotion.
Diastereoselective addition of vinyl organometallic reagents to l-serinal

Abstract An examination of the diastereoselective addition of vinyl organometalic reagents to N-BOC l -serinal acetonide (1) to afford mixtures of syn-2 and anti-2 is presented. Vinylzinc chloride in nonpolar solvents was found to add to the aldehyde carbonyl of 1 with 6:1 syn/anti stereoselectivity in excellent yields.
Optimal Incentive Contracts and Information Cascades

We examine information aggregation regarding industry capital productivity from privately informed managers in a dynamic model with optimal incentive contracts. Information cascades always occur if managers enjoy limited liability: when beliefs regarding productivity become endogenously extreme (optimistic or pessimistic), learning stops. There is no learning if initial beliefs are extreme, or if agency conflicts are severe. In contrast to the literature, cascades occur even when signals have unbounded precision or when there are rich action spaces. Relaxing limited liability constraints is not sufficient to avoid cascades; we provide sufficient conditions for efficient information aggregation through incentive contracts.
Calculating Compensation in Cases of Wrongful Death

Abstract Death statutes in the United States list elements of loss for which a defendant must make compensatory payment. The element that economists as expert witnesses are called upon to calculate is net income, roughly defined as the decedent's income minus personal expenses. The existence of joint or shared consumption goods complicates the definition and calculation of net income. Net income can be interpreted as the money required for survivors to attain the same standard of living as before. Equivalence scales traditionally used for this type of calculation are flawed. A new method for calculating net income is proposed, based on a collective household model.
Microresonator-based comb generation without an external laser source

We demonstrate a fiber-microresonator dual-cavity architecture with which we generate 880 nm of comb bandwidth without the need for a continuous-wave pump laser. Comb generation with this pumping scheme is greatly simplified as compared to pumping with a single frequency laser, and the generated combs are inherently robust due to the intrinsic feedback mechanism. Temporal and radio frequency (RF) characterization show a regime of steady comb formation that operates with reduced RF amplitude noise. The dual-cavity design is capable of being integrated on-chip and offers the potential of a turn-key broadband multiple wavelength source.
Indeterminacy of intertemporal equilibria under imperfect competition

It is known that overlapping generations models with imperfectly competitive firms may exhibit a continuum of stationary equilibria. The reason of this indeterminacy is that different price expectation functions of consumers lead to different objective demand functions against which firms maximize. All these expectation functions fulfill perfect foresight in the equilibrium, but they can be arbitrary off the equilibrium. In this paper it is shown that it is not this arbitrariness which is responsible for the indeterminacy, but that the continuum of stationary equilibria emerges even if expectation functions are rational.
Borane-containing polyolefins: synthesis and applications

Abstract This article summarizes the experimental results in the synthesis and applications of borane containing polyolefins. It is becoming clear that the introduction of borane groups into polyolefins, such as polyethylene (PE) and polypropylene (PP), is a valuable route for achieving their functionalization, which has been a long scientific challenge and industrial needed technology. The trialkyborane moieties, unlike other organic functional groups, are stable to early transition metal (Lewis acid) complexes and compatible with olefin monomers. Therefore, borane-containing monomers can be effectively incorporated into polyolefins via Ziegler–Natta and metallocene copolymerization reactions. In turn, the borane group that is incorporated into the polymer not only can be quantitatively converted to a hydroxy group, but it also can be transformed into a stable polymeric radical that then initiates a living free radical polymerization of the functional monomers. The functional group and functional group concentration are basically governed by the monomers that are introduced. The resulting graft and block copolymers, having well-controlled molecular structures, would be very difficult to prepare by existing methods.
The effect of integration time on fluctuation measurements: calibrating an optical trap in the presence of motion blur

Dynamical instrument limitations, such as finite detection bandwidth, do not simply add statistical errors to fluctuation measurements, but can create significant systematic biases that affect the measurement of steady-state properties. Such effects must be considered when calibrating ultra-sensitive force probes by analyzing the observed Brownian fluctuations. In this article, we present a novel method for extracting the true spring constant and diffusion coefficient of a harmonically confined Brownian particle that extends the standard equipartition and power spectrum techniques to account for video-image motion blur. These results are confirmed both numerically with a Brownian dynamics simulation, and experimentally with laser optical tweezers.
On Expectations-Driven Business Cycles in Economies with Production Externalities: A Comment

Eusepi (2009, International Journal of Economic Theory 5, pp. 9-23) analytically finds that a one-sector real business cycle model may exhibit positive co-movement between consumption and investment when the equilibrium wage-hours locus is positively-sloped and steeper than the household's labor supply curve. However, we show that this condition does not imply expectations-driven business cycles will emerge in Eusepi's model. Specifically, a positive news shock about future productivity improvement leads to an aggregate recession whereby output, employment, consumption and investment all fall in the announcement period.
General Allylic C–H Alkylation with Tertiary Nucleophiles

A general method for intermolecular allylic C− H alkylation of terminal olefins with tertiary nucleophiles has been accomplished employing palladium(II)/bis(sulfoxide) catalysis. Allylic C−H alkylation furnishes products in good yields (avg. 64%) with excellent regio- and stereoselectivity (>20:1 linear:branched, >20:1 E:Z). For the first time, the olefin scope encompasses unactivated aliphatic olefins as well as activated aromatic/heteroaromatic olefins and 1,4-dienes. The ease of appending allyl moieties onto complex scaffolds is leveraged to enable this mild and selective allylic C−H alkylation to rapidly diversify phenolic natural products. The tertiary nucleophile scope is broad and includes latent functionality for further elaboration (e.g., aliphatic alcohols, α,β-unsaturated esters). The opportunities to effect synthetic streamlining with such general C−H reactivity are illustrated in an allylic C−H alkylation/Diels−Alder reaction cascade: a reactive diene is generated via intermolecular allylic C−H alkylation and approximated to a dienophile contained within the tertiary nucleophile to furnish a common tricyclic core found in the class I galbulimima alkaloids.
A Healthy Economy Can Break Your Heart

Panel data methods are used to investigate how deaths from coronary heart disease (CHD) in the United States vary with macroeconomic conditions. A one-percentage-point reduction in unemployment is predicted to raise CHD mortality by 0.75%, corresponding to almost 3,900 additional fatalities. The increase in relative risk is similar across age groups, implying that senior citizens account for most of the extra deaths. Direct evidence is obtained of a role for decreases in medical interventions treating coronary problems. CHD mortality increases rapidly when the economy strengthens but returns to or near its baseline level within five years for most groups.
Self-Aligned Ballistic Molecular Transistors and Electrically Parallel Nanotube Arrays

Carbon nanotube field-effect transistors with structures and properties near the scaling limit with short (down to 50 nm) channels, self-aligned geometries, palladium electrodes with low contact resistance, and high-K dielectric gate insulators are realized. Electrical transport in these miniature transistors is nearly ballistic up to high biases at both room and low temperatures. Atomic-layer-deposited (ALD) high-K films interact with nanotube sidewalls via van der Waals interactions without causing weak localization at 4 K. New fundamental understanding of ballistic transport, optical phonon scattering, and potential interfacial scattering mechanisms in nanotubes is obtained. Also, parallel arrays of such molecular transistors are enabled to deliver macroscopic currents-an important milestone for future circuit applications.
A performance study of monitoring and information services for distributed systems

Monitoring and information services form a key component of a distributed system, or Grid. A quantitative study of such services can aid in understanding the performance limitations, advise in the deployment of the monitoring system, and help evaluate future development work. To this end, we study the performance of three monitoring and information services for distributed systems: the Globus Toolkit/spl reg/ Monitoring and Discovery Service (MDS2), the European Data Grid Relational Grid Monitoring Architecture (R-GMA) and Hawkeye, part of the Condor project. We perform experiments to test their scalability with respect to number of users, number of resources and amount of data collected. Our study shows that each approach has different behaviors, often due to their different design goals. In the four sets of experiments we conducted to evaluate the performance of the service components under different circumstances, we found a strong advantage to caching or pre-fetching the data, as well as the need to have primary components at well-connected sites because of the high load seen by all systems.
OUTER VAN ALLEN BELTS AND NEUTRAL POINTS ON INTERFACE BETWEEN SOLAR WIND AND GEOMAGNETIC FIELD

Abstract : The two N-1 (neutral) points are believed to be the key mechanisms of trapping high-energy particles in the outer Van Allen belts. Their neighborhoods allow the solar wind plasma to seep into the geomagnetic field without reflection. Their instability causes the connected interface to oscillate locally, inducing magnetohydrodynamic waves which increase the energy of the trapped particles to much higher levels in succeeding steps. Even when the solar wind is not steady, the above conclusions are expected to be valid, except that the interface may change its position. Furthermore, those mechanisms of trapped particles and boosting energy become more effective. (Author)
The refraction of shock waves at a gaseous interface

A programme of shock tube experiments has been conducted to study the refraction of plane shock waves at interfaces between two gases. Shocks of strength ζ = 0·85 (weak) and ζ = 0·30 (fairly strong) were allowed to impinge, at various angles of incidence, on interfaces between air/CO2 and air/CH4, and the resulting configurations were photographed through a Mach-Zehnder interferometer. From the interferograms, measurements were made of the strengths of the reflected waves, and of the angles of refraction, and the values were compared with the theoretical calculations of Polachek & Seeger (1951). Within the range of parameters for which the refraction model assumed by the theory is applicable–the so-called ‘regular refraction’ region–the observations were in excellent agreement with the theoretical predictions.When the study was extended to ranges of the parameters for which the theory is clearly inadequate, a succession of rather complex ‘irregular refraction’ patterns was observed. Although these configurations were highly interesting qualitatively, each of them involved curved shocks, non-uniform regions of flow, and other less simple processes which discouraged any formal theoretical analysis. On a less rigorous basis, however, it could be shown that these patterns were internally consistent, and that each represented a distortion of a regular refraction process which was reasonable under the prevailing aerodynamic conditions.Certain observations in these refraction experiments appear to be of some significance outside the specific problem. (i) The sensitivity of strong shock refractions to the values of the specific heat ratio λ for the two gases suggests a possible technique for the measurement of λ and its temperature dependence. (ii) Two of the irregular refraction patterns display a transition process which would be equally appropriate to the onset of the Mach configuration in the shock reflection problem. (iii) Some irregular refractions can be considered as special cases in the problem of the interaction of a shock and a boundary layer.
Iterative Method Applied To Image Reconstruction And To Computer-Generated Holograms

This paper discusses an iterative computer method that can be used to solve a number of problems in optics. This method can be applied to two types of problems: (1) synthesis of a Fourier transform pair having desirable properties in both domains, and (2) reconstruction of an object when only partial information is available in any one domain. Illustrating the first type of problem, the method is applied to spectrum shaping for computer-generated holograms to reduce quantization noise. A problem of the second type is the reconstruction of astronomical objects from stellar speckle interferometer data. The solution of the latter problem will allow a great increase in resolution over what is ordinarily obtainable through a large telescope limited by atmospheric turbulence. Experimental results are shown. Other applications are mentioned briefly.
Selecting an Appropriate Publication Outlet: A Comprehensive Model of Journal Selection Criteria for Researchers in a Broad Range of Academic Disciplines

Building upon previously published articles from 18 different disciplines, this research delves into the area of how academics inform one another, addressing the issue of how academic scholars can determine the optimum journal for submission of their research. A comprehensive model of the journal selection process is developed, including 39 detailed considerations spread over three major categories: likelihood of timely acceptance; potential impact of the manuscript (journal credibility, prestige, visibility); and philosophical and ethical issues. Specific guidelines are given for evaluating such concepts as manuscript-journal “fit,” journal prestige, and journal visibility. The graphical model developed here assists authors in comparing journal alternatives and provides new researchers with insights into how the three primary journal selection categories are weighed and balanced. In addition, less commonly understood concepts, such as Time to Publication, Review Cycle Time Delay, and Publication Time Delay, are identified and named, and their relationships are defined in this article. On a broader level, this research demonstrates that scholars across disciplines have substantial common interests with respect to journal publishing, that the ties that unite academics seeking to publish are strong, and that the potential for future crossdisciplinary research in the area of how academics inform one another is correspondingly robust.
Viscous Shock Layer Solutions for Hypersonic Sphere-Cones

Abstract : An analysis and numerical solution of the fully viscous shock layer equations for hypersonic flow past spherically blunted cones is presented. Attention is drawn to the adverse effect in the numerical solution due to discontinuities in the flow derivatives caused by the discontinuity in the surface curvature at the sphere/cone tangency point, when the usual surface coordinate frame of reference is used. It is shown that a finite difference formulation that accounts for the imbedded gradient discontinuities resolves these numerical difficulties. This concept is demonstrated through a numerical scheme which utilizes a time dependent relaxation technique for the bow shock shape. A model problem analogous to the sphere/cone juncture problem is first formulated and finite difference schemes developed and demonstrated for this case. This approach is then extended to the solution of the viscous shock layer equations for hypersonic flow past spherically blunted cones with half cone angles varying from 30 deg to 0 deg at high Reynolds number. For these cases the present results are found to compare well with independent inviscid flow calculations. In addition, excellent comparisons with experimental pressure and heat transfer data on a 7.5 deg half angle cone are obtained.
Asymmetric Induction With Cyclodextrins: Photocyclization of Tropolone Alkyl Ethers

Employing the photobehavior of tropolone alkyl ethers as the probe, we have established that cyclodextrins could as a serve as a medium to bring about enantioselective photoreactions. The enantioselectivity observed in this study is moderate at best. The enantioselectivity observed in the solid state in comparison to aqueous solution suggests that a rigid environment may be essential to achieve chiral induction during photoreactions of organic molecules. In this context the much higher enantioselectivity observed for the same systems within zeolites is noteworthy.
Synthesis of azapolycyclic systems via the intramolecular [4 + 2] cycloaddition chemistry of 2-(alkylthio)-5-amidofurans.

A series of 2-(methylthio)-5-amidofurans containing tethered unsaturation were prepared via the reaction of dimethyl(methylthio)sulfonium tetrafluoroborate (DMTSF) with β-alkoxy-γ-dithiane amides 13−16 and 27−32 in 40−70% yield. Thermolysis of these furans resulted in an intramolecular Diels−Alder reaction (IMDAF). With the exception of 45 and 46, the oxa-bridged cycloadducts could not be isolated but immediately underwent a 1,2-methylthio shift to form bicyclic lactams in 60−100% yield. It was determined that incorporation of the amido carbonyl in the tether allowed the IMDAF reaction to proceed at a lower temperature. A dramatic example of this is seen in the IMDAF reaction of furan 35, in which the presence of an amido carbonyl as part of the dienophile tether, as opposed to the annealed ring (66) or the lack of a carbonyl (67), was necessary for the cycloaddition to occur. Furan 37, annealed to an azepine ring, underwent the IMDAF reaction at or below room temperature. To identify structural features ...
Novel synthetic pathways to wide bandgap semiconductors in the Si?C?Al?N system

Abstract Epitaxial SiCAlN films with single-phase wurtzite structures were grown by molecular beam epitaxy via reactions of a specifically designed molecular precursor H 3 SiCN and Al atoms at 750 °C, considerably below the miscibility gap of SiC and AlN at 1900 °C. The film growth was conducted directly on Si(111) despite the 19% lattice mismatch between the two materials. Commensurate heteroepitaxy was facilitated by the conversion of native and thermally grown SiO 2 layers into crystalline Si–Al–N–O interfaces in registry with the Si(111) surface. This crystalline interface acted as a template for nucleation and growth of SiCAlN. Integration of wide bandgap semiconductors including AlN and GaN with Si was achieved by this process. Perfectly epitaxial SiCAlN was also grown on 6H-SiC(0001) substrates and exhibited novel crystallographic and physical properties such as hexagonal structures with 2H/2H and 4H/2H SiC/AlN stacking, metastable cubic structures, wide bandgaps in the UV, and extreme mechanical hardness. These properties have been measured by a wide range of characterization techniques and ab initio density functional theory simulations have been used to elucidate the structural and spectroscopic behavior.
A Potentially Valuable Advance in the Synthesis of Carbohydrate-Based Anticancer Vaccines through Extended Cycloaddition Chemistry

An advance in the long-term problem of joining complex oligosaccharides to polypeptides and even proteins is described herein. The key method involves equipping the oligosaccharide sector with an azide and the polypeptide with pendant alkynyl functionality. The two sectors are joined through a "click-like" cycloaddition. The method encompasses oligosaccharide constructs with several azide linkages which undergo concurrent cycloaddition to peptide-based acetylenes. This technology could well prove to be useful in the construction of fully synthetic vaccines.
Potassium Hydride in Paraffin: A Useful Base for Organic Synthesis

The preparation of potassium hydride as a 1:1 homogenate with paraffin, termed KH(P), is reported. KH(P), a solid at room temperature, is stable without special handling. On suspension in THF with a phosphonium salt, KH(P) rapidly generates the ylide. Wittig condensation with aromatic, aliphatic, and α,β-unsaturated aldehydes proceeds with high Z selectivity. KH(P) should be a generally useful base for organic synthesis.
On the Causes of Evolutionary Transition:Transversion Bias

A pattern in which nucleotide transitions are favored several fold over transversions is common in molecular evolution. When this pattern occurs among amino acid replacements, explanations often invoke an effect of selection, on the grounds that transitions are more conservative in their effects on proteins. However, the underlying hypothesis of conservative transitions has never been tested directly. Here we assess support for this hypothesis using direct evidence: the fitness effects of mutations in actual proteins measured via individual or paired growth experiments. We assembled data from 8 published studies, ranging in size from 24 to 757 single-nucleotide mutations that change an amino acid. Every study has the statistical power to reveal significant effects of amino acid exchangeability, and most studies have the power to discern a binary conservative-vs-radical distinction. However, only one study suggests that transitions are significantly more conservative than transversions. In the combined set of 1,239 replacements (544 transitions, 695 transversions), the chance that a transition is more conservative than a transversion is 53 % (95 % confidence interval 50 to 56) compared with the null expectation of 50 %. We show that this effect is not large compared with that of most biochemical factors, and is not large enough to explain the several-fold bias observed in evolution. In short, the available data have the power to verify the "conservative transitions" hypothesis if true, but suggest instead that selection on proteins plays at best a minor role in the observed bias.
Habitat Partitioning by Three Species of Dolphins in Santa Monica Bay, California

Abstract Habitat partitioning by bottlenose dolphins (Tursiops truncatus), short-beaked common dolphins (Delphinus delphis), and long-beaked common dolphins (D. capensis), were assessed during 178 surveys conducted between 1997–2000 in Santa Monica Bay, California. Bottlenose dolphins were found year-round within 0.5 km from shore in 80.0 % of the sightings (n = 137) but they were also found in deeper waters further offshore. The two common dolphin species were observed year-round (n = 83) far from shore and near escarpments; they were sympatric but never seen in mixed schools. This study suggests that habitat partitioning in the bay probably relates to resource partitioning among three dolphins species with roughly similar ecological needs.