cssi/SciSciGPT-SciSciNet huggingface dataset:
Upper bounds for binary and ternary decision feedback equalization of the magnetic recording channel

A new technique proposed by Altekar and Beaulieu (see IEEE Trans. Inform. Theory, vol.39, p.145-56, Jan. 1993) for determining the upper bound to the probability of error of a decision feedback equalizer is applied to the magnetic recording channel (MRC). The upper bound on the probability of a symbol error is calculated as a function of the channel information density for both binary and ternary decision feedback equalization of the MRC. The MRC is modeled as a linear channel with a Lorentzian step response, additive white Gaussian noise, and perfect timing. A comparison of the binary and ternary MRC under these assumptions shows that in the absence of channel coding, the binary MRC is preferred for information densities of interest. However, the ternary MRC may have an advantage when channel coding is used at high information densities. >
Targets and systems of health care cost control.

Discussion of health care cost control policy and politics tends to focus on terms such as "market," "government," and "managed care" that are either too general or too value laden to encourage sound analysis. This article proposes an alternative framework for classifying cost control policies. It first distinguishes targets from systems of control. Targets can then be divided into categories of service (e.g., hospital care, pharmaceutical treatment) and components of cost (e.g., price and volume). Systems can be classified in terms of the degree of pooling of finance, ranging from no insurance to a single pool of funds, and how payment of providers is organized, ranging from all payers paying all providers on the same terms to extensive selective contracting among payers and providers. The article analyzes examples of target policy and politics, system policy and politics, and how system choices can influence which targets are targeted how well, so as to show that both policy consequences and political alignments become clearer by using these terms. As one instance, discussions of "managed care" are often confused because the term has two meanings, one referring to target policy and one to system policy.
Justifications for logic programs under answer set semantics

The paper introduces the notion of offline justification for answer set programming (ASP). Justifications provide a graph-based explanation of the truth value of an atom with respect to a given answer set. The paper extends also this notion to provide justification of atoms during the computation of an answer set (on-line justification) and presents an integration of online justifications within the computation model of SMODELS. Offline and online justifications provide useful tools to enhance understanding of ASP, and they offer a basic data structure to support methodologies and tools for debugging answer set programs. A preliminary implementation has been developed in .
Snaxels on a plane

While many algorithms exist for tracing various contours for illustrating a meshed object, few algorithms organize these contours into region-bounding closed loops. Tracing closed-loop boundaries on a mesh can be problematic due to switchbacks caused by subtle surface variation, and the organization of these regions into a planar map can lead to many small region components due to imprecision and noise. This paper adapts "snaxels," an energy minimizing active contour method designed for robust mesh processing, and repurposes it to generate visual, shadow and shading contours, and a simplified visual-surface planar map, useful for stylized vector art illustration of the mesh. The snaxel active contours can also track contours as the mesh animates, and frame-to-frame correspondences between snaxels lead to a new method to convert the moving contours on a 3-D animated mesh into 2-D SVG curve animations for efficient embedding in Flash, PowerPoint and other dynamic vector art platforms.
Thermally enhanced blue light-emitting diode

We investigate thermoelectric pumping in wide-bandgap GaN based light-emitting diodes (LEDs) to take advantage of high junction temperature rather than avoiding the problem of temperature-induced efficiency droop through external cooling. We experimentally demonstrate a thermally enhanced 450 nm GaN LED, in which nearly fourfold light output power is achieved at 615 K (compared to 295 K room temperature operation), with nearly no reduction in the wall-plug efficiency (i.e., electrical-optical energy conversion efficiency) at bias V<ℏω/q. The LED is shown to work in a mode similar to a thermodynamic heat engine operating with charged carriers pumped into the active region by a combination of electrical work and Peltier heat (phonons) drawn from the lattice. In this optimal operating regime at 615 K, the LED injection current (3.26 A/cm2) is of similar magnitude to the operating point of common high power GaN based LEDs (5–35 A/cm2). This result suggests the possibility of removing bulky heat sinks in curre...
State-of-the-Art in Sequential Change-Point Detection

We provide an overview of the state-of-the-art in the area of sequential change-point detection assuming discrete time and known pre- and post-change distributions. The overview spans over all major formulations of the underlying optimization problem, namely, Bayesian, generalized Bayesian, and minimax. We pay particular attention to the latest advances in each. Also, we link together the generalized Bayesian problem with multi-cyclic disorder detection in a stationary regime when the change occurs at a distant time horizon. We conclude with two case studies to illustrate the cutting edge of the field at work.
Wrinkling of inhomogeneously strained thin polymer films

Wrinkles occur due to a mechanical instability when sufficient strain is applied to an incompressible thin film attached to a deformable substrate. For wrinkles made with a polymer film supported on a soft elastomer, the amplitude is directly proportional to the wavelength and the square root of the applied strain. This dependence has been confirmed with ideal substrates where the global strain is homogeneously distributed, but the influence of strain inhomogeneity has not been considered previously. We use the contact line wrinkling technique to prepare polystyrene thin films with periodic regions of different wrinkle amplitudes, hence strains, on soft substrates. We find that an inhomogeneously strained surface approaches amplitude homogeneity globally upon the application of sufficiently large strains. We derive relationships to describe this process, providing fundamental knowledge of the wrinkling mechanism.
Functionalized Tetrazoles from Cyanogen Azide with Secondary Amines

Secondary amines react with cyanogen azide at ambient temperature in water/acetonitrile to provide tetrazole derivatives directly. The scope and limitations with regard to steric hindrance of the amine are discussed. Although reaction yields are moderate, 29–81 %, the cyanogen azide reactions provide a direct and versatile route to functionalized tetrazoles that may be especially useful considering the diversity of amines suitable for this transformation. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Was Postwar Suburbanization “White Flight”? Evidence from the Black Migration

Residential segregation across jurisdiction lines generates disparities in public services and education by race. The distinctive American pattern - in which blacks live in the center city and whites in the suburban ring - was enhanced by black migration from the rural South from 1940-1970. I show that urban whites responded to this black influx by relocating to the suburbs and rule out the indirect effect on urban housing prices as a cause. Black migrants may have been attracted to areas already undergoing suburbanization. I create an instrument for changes in urban diversity that predicts black migrant flows from southern states and assigns these flows to northern cities according to established settlement patterns. The best causal estimates imply that "white flight" explains around 20 percent of suburban growth in the postwar period.
Structured product labeling improves detection of drug-intolerance issues.

Abstract Objectives This study sought to assess the value of the Health Level 7/U.S. Food and Drug Administration Structured Product Labeling (SPL) drug knowledge representation standard and its associated terminology sources for drug-intolerance (allergy) decision support in computerized provider order entry (CPOE) systems. Design The Regenstrief Institute CPOE drug-intolerance issue detection system and its knowledge base was compared with a method based on existing SPL label content enriched with knowledge sources used with SPL (NDF-RT/MeSH). Both methods were applied to a large set of drug-intolerance (allergy) records, drug orders, and medication dispensing records covering >50,000 patients over 30 years. Measurements The number of drug-intolerance issues detected by both methods was counted, as well as the number of patients with issues, number of distinct drugs, and number of distinct intolerances. The difference between drug-intolerance issues detected or missed by either method was qualitatively analyzed. Results Although Conclusion The SPL-based approach is more sensitive and suggests that mapping local dictionaries to SPL, and enhancing the depth and breadth of coverage of SPL content are worth accelerating. The study also highlights specificity problems known to trouble drug-intolerance decision support and suggests how terminology and methods of recording drug intolerances could be improved.
A semidefinite representation for some minimum cardinality problems

Using techniques developed , we show that some minimum cardinality problems subject to linear inequalities can be represented as finite sequences of semidefinite programs. In particular, we provide a semidefinite representation and a set of successively finer relaxations for the minimum rank problem on positive semidefinite matrices and for the minimum cardinality problem subject to linear inequalities.
The public accounting industry production function

Abstract A translog function is specified to represent the relation between revenue and human resource inputs in public accounting firms. Estimation of the model using a balanced panel of annual data for 64 large CPA firms for the period 1995–1999 indicates that increasing returns to scale prevail in the public accounting industry, justifying recent merger and acquisition activities among accounting firms. Average marginal revenue product of partners increased monotonically from 1995 to 1998, decreased slightly in 1999, and was about nine times that of other professionals during 1995–1999. The public accounting industry exhibited continuing improvement in productivity over the 5 years.
Transparent checkpoint-restart over infiniband

Transparently saving the state of the InfiniBand network as part of distributed checkpointing has been a long-standing challenge for researchers. The lack of a solution has forced typical MPI implementations to include custom checkpoint-restart services that "tear down" the network, checkpoint each node in isolation, and then re-connect the network again. This work presents the first example of transparent, system-initiated checkpoint-restart that directly supports InfiniBand. The new approach simplifies current practice by avoiding the need for a privileged kernel module. The generality of this approach is demonstrated by applying it both to MPI and to Berkeley UPC (Unified Parallel C), in its native mode (without MPI). Scalability is shown by checkpointing 2,048 MPI processes across 128 nodes (with 16 cores per node). The run-time overhead varies between 0.8% and 1.7%. While checkpoint times dominate, the network-only portion of the implementation is shown to require less than 100 milliseconds (not including the time to locally write application memory to stable storage).
Time as a determinant of comparative advantage

It is assumed that added time to export adds cost to and lowers the volume of trade. Time delays may also affect the composition of trade and can disproportionately reduce trade in time-sensitive goods. This paper investigates the validity of these propositions using the World Bank Doing Business database and Enterprise Surveys for 64 developing countries. The authors find that in countries where there is longer time needed to export firms in time-sensitive industries are less likely to become exporters. Moreover, firms that do export have lower export intensities. Their findings imply that time to export is a significant determinant of comparative advantage. For example, consider two industries that have the same export probability and intensity - but differ in time-sensitivity by one standard deviation. Action taken to cut time to export by 50 percent for one industry opens a 6 percentage point difference between the export probabilities of the two industries. In addition, steps to cut time delays increase export intensities by 1.9 percentage points. This impact applies to industries with different productivity levels -- and those in developing countries with different income levels.
Explicit Codes Achieving List Decoding Capacity: Error-Correction With Optimal Redundancy

In this paper, we present error-correcting codes that achieve the information-theoretically best possible tradeoff between the rate and error-correction radius. Specifically, for every 0 < R < 1 and epsiv < 0, we present an explicit construction of error-correcting codes of rate that can be list decoded in polynomial time up to a fraction (1- R - epsiv) of worst-case errors. At least theoretically, this meets one of the central challenges in algorithmic coding theory. Our codes are simple to describe: they are folded Reed-Solomon codes, which are in fact exactly Reed-Solomon (RS) codes, but viewed as a code over a larger alphabet by careful bundling of codeword symbols. Given the ubiquity of RS codes, this is an appealing feature of our result, and in fact our methods directly yield better decoding algorithms for RS codes when errors occur in phased bursts. The alphabet size of these folded RS codes is polynomial in the block length. We are able to reduce this to a constant (depending on epsiv) using existing ideas concerning ldquolist recoveryrdquo and expander-based codes. Concatenating the folded RS codes with suitable inner codes, we get binary codes that can be efficiently decoded up to twice the radius achieved by the standard GMD decoding.
The Schwarzian derivative and measured laminations on Riemann surfaces

A holomorphic quadratic differential on a hyperbolic Rie- mann surface has an associated measured foliation, which can be straight- ened to yield a measured geodesic lamination. On the other hand, a quadratic differential can be considered as the Schwarzian derivative of a 1 structure, to which one can naturally associate another measured geodesic lamination using grafting. We compare these two relationships between quadratic differentials and measured geodesic laminations, each of which yields a homeomor- phism ML(S) ! Q(X) for each conformal structure X on a compact surface S. We show that these maps are nearly the same, differing by a multiplicative factor of 2 and an error term of lower order than the maps themselves (which we bound explicitly). As an application we show that the Schwarzian derivative of a 1 structure with Fuchsian holonomy is close to a 2�-integral Jenkins- Strebel differential. We also study compactifications of the space of 1 structures using the Schwarzian derivative and grafting coordinates; we show that the natural map between these extends to the boundary of each fiber over Teichmuller space, and we describe this extension.
The structure of the vorticity field in turbulent channel flow. Part 2. Study of ensemble-averaged fields

Several conditional sampling techniques are applied to a data base generated by large-eddy simulation of turbulent channel flow. It is shown that the bursting process is associated with well-organized horseshoe vortices inclined at about 45 deg. to the wall. These vortical structures are identified by examining the vortex lines of three-dimensional, ensemble averaged vorticity fields. Two distinct horseshoe-shaped vortices corresponding to the sweep and ejection events are detected. These vortices are associated with high Reynolds shear stress and hence make a significant contribution to turbulent energy production. The dependency of the ensemble averaged vortical structures on the detection criteria, and the question of whether this ensemble-averaged structure is an artifact of the ensemble averaging process are examined. The ensemble-averaged pattern of these vortical structures that emerge from the analysis could provide the basis for a hypothetical model of the organized structures of wall-bounded shear flows.
Exploring the Synthetic Applicability of a Cyanobacterium Nitrilase as Catalyst for Nitrile Hydrolysis

The substrate specificity and synthetic applicability of the nitrilase from cyanobacterium Synechocystis sp. strain PCC 6803 have been examined. This nitrilase catalyzed the hydrolysis of both aromatic and aliphatic nitriles to the corresponding acids in high yields. Furthermore, the stereoselective hydrolysis of phenyl-substituted β-hydroxy nitriles to (S)-enriched β-hydroxy carboxylic acids and selective hydrolysis of α,ω-dinitriles with five or less methylene groups to ω-cyano carboxylic acids have been achieved. This suggested that nitrilase from Synechocystis sp. PCC 6803 could be a useful enzyme catalyst for the “green” nitrile hydrolysis. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Chromene chromium carbene complexes in the syntheses of naphthopyran and naphthopyrandione units present in photochromic materials and biologically active natural products.

The carbene complex 5-(2,2-dimethyl-2H-chromene)methoxylmethylene chromium pentacarbonyl will undergo a benzannulation reaction with phenylacetylene, 1-pentyne, 3-hexyne, and trimethylsilylacetylen...
The compact genetic algorithm

Introduces the compact genetic algorithm (cGA) which represents the population as a probability distribution over the set of solutions and is operationally equivalent to the order-one behavior of the simple GA with uniform crossover. It processes each gene independently and requires less memory than the simple GA. The development of the compact GA is guided by a proper understanding of the role of the GA's parameters and operators. The paper clearly illustrates the mapping of the simple GA's parameters into those of an equivalent compact GA. Computer simulations compare both algorithms in terms of solution quality and speed. Finally, this work raises important questions about the use of information in a genetic algorithm, and its ramifications show us a direction that can lead to the design of more efficient GAs.
Hausdorff Dimension of the SLE Curve Intersected with the Real Line

We establish an upper bound on the asymptotic probability of an $SLE(\kappa)$ curve hitting two small intervals on the real line as the interval width goes to zero, for the range $4 < \kappa < 8$. As a consequence we are able to prove that the random set of points in $R$ hit by the curve has Hausdorff dimension $2-8/\kappa$, almost surely.
Diffusion NMR methods applied to xenon gas for materials study

We report initial NMR studies of (i) xenon gas diffusion in model heterogeneous porous media and (ii) continuous flow laser-polarized xenon gas. Both areas utilize the pulsed gradient spin-echo (PGSE) techniques in the gas phase, with the aim of obtaining more sophisticated information than just translational self-diffusion coefficients--a brief overview of this area is provided in the Introduction. The heterogeneous or multiple-length scale model porous media consisted of random packs of mixed glass beads of two different sizes. We focus on observing the approach of the time-dependent gas diffusion coefficient, D(t) (an indicator of mean squared displacement), to the long-time asymptote, with the aim of understanding the long-length scale structural information that may be derived from a heterogeneous porous system. We find that D(t) of imbibed xenon gas at short diffusion times is similar for the mixed bead pack and a pack of the smaller sized beads alone, hence reflecting the pore surface area to volume ratio of the smaller bead sample. The approach of D(t) to the long-time limit follows that of a pack of the larger sized beads alone, although the limiting D(t) for the mixed bead pack is lower, reflecting the lower porosity of the sample compared to that of a pack of mono-sized glass beads. The Pade approximation is used to interpolate D(t) data between the short- and long-time limits. Initial studies of continuous flow laser-polarized xenon gas demonstrate velocity-sensitive imaging of much higher flows than can generally be obtained with liquids (20-200 mm s-1). Gas velocity imaging is, however, found to be limited to a resolution of about 1 mm s-1 owing to the high diffusivity of gases compared with liquids. We also present the first gas-phase NMR scattering, or diffusive-diffraction, data, namely flow-enhanced structural features in the echo attenuation data from laser-polarized xenon flowing through a 2 mm glass bead pack. c2002 John Wiley & Sons, Ltd.
Thermodynamic and Kinetic Study of Phase Transformations in Solder/Metal Systems

Diffusion in both the Pd‐Sn and Cu‐Sn systems has been investigated using differential scanning calorimetry. Averaged interdiffusion coefficients for the PdSn 4 , PdSn 2 and Cu 3 Sn intermetallics have been calculated, where equilibrium concentrations in the diffusion couples are assumed. There is an obvious hierarchy within the Pd‐Sn system where diffusion is fastest in the most Sn‐rich intermetallic. Comparisons within each system, including consideration of the solute diffusion coefficients in pure Sn, provide evidence that in the most Sn rich phase (e.g. PdSn 4 ) the interstitial diffusion of metal atoms is the dominant reaction mechanism. In contrast, the diffusion coefficient for the Cu‐rich phase Cu 3 Sn was found to be five orders of magnitude smaller than the solute diffusion coefficient for Cu in pure Sn.
Fine-Grained Authorization for Job Execution in the Grid: Design and Implementation

In this paper, we describe our work on enabling fine-grained authorization for resource usage and management. We address the need of virtual organizations to enforce their own polices in addition to those of the resource owners, with regards to both resource consumption and job management. To implement this design, we propose changes and extensions to the Globus Toolkit's version 2 resource management mechanism. We describe the prototype and policy language that we have designed to express fine-grained policies and present an analysis of our solution. Copyright © 2004 John Wiley & Sons, Ltd.
SPIN—an extensible microkernel for application-specific operating system services

Application domains such as multimedia, databases, and parallel computing, require operating system services with high performance and high functionality. Existing operating systems provide fixed interfaces and implementations to system services and resources. This makes them inappropriate for applications whose resource demands and usage patterns are poorly matched by the services provided. The SPIN operating system enables system services to be defined in an application-specific fashion through an extensible microkernel. It offers applications fine-grained control over a machine's logical and physical resources through run-time adaptation of the system to application requirements.
A fractional- N frequency synthesizer architecture utilizing a mismatch compensated PFD/DAC structure for reduced quantization-induced phase noise

Techniques are proposed to dramatically reduce the impact of quantization noise in /spl Sigma//spl Delta/ fractional-N synthesizers, thereby improving the existing tradeoff between phase noise and bandwidth that exists in these systems. The key innovation is the introduction of new techniques to overcome nonidealities in a phase-frequency detector (PFD)/digital-to-analog converter (DAC) structure, which combines the functionality of both phase detector and cancellation DAC into a single element. The proposed architecture achieves better gain matching between the phase-error signal and cancellation DAC than offered by previous approaches. Dynamic element matching techniques are introduced to mitigate the effects of PFD/DAC unit element and timing mismatch on synthesizer phase noise performance. We present behavioral simulations of an example application of this technique that demonstrates 36 dB reduction in broad-band quantization-induced phase noise with the use of a 7-b PFD/DAC. Simulations further demonstrate that fractional spurs are rejected to levels <-90 dBc when a low-cost, low-overhead digital gain correction technique is employed.
Criterion for Cannon’s Conjecture

The Cannon Conjecture from the geometric group theory asserts that a word hyperbolic group that acts effectively on its boundary, and whose boundary is homeomorphic to the 2-sphere, is isomorphic to a Kleinian group. We prove the following Criterion for Cannon’s Conjecture: a hyperbolic group G (that acts effectively on its boundary) whose boundary is homeomorphic to the 2-sphere is isomorphic to a Kleinian group if and only if every two points in the boundary of G are separated by a quasi-convex surface subgroup. Thus, the Cannon’s conjecture is reduced to showing that such a group contains “enough” quasi-convex surface subgroups.
Electrotelluration: A New Approach to Tri- and Tetrasubstituted Alkenes

A novel electrotelluration process is described in which a Michael addition of an alkyl or aryl tellurolate anion occurs onto an activated alkyne with subsequent trapping of a vinyl anion with electrophiles (aldehydes and ketones) other than a proton. This process provides an efficient regio- and stereospecific route to tri- and tetrasubstituted alkenes. Methodologically significant examples of this chemistry were studied in which aryl and alkyl tellurolate anions were added to ω-keto alkynyl esters in a Michael reaction, and the incipient vinyl anions were trapped intramolecularly by the internal aldehydes. The reactive centers were tethered by different lengths of alkyl chains to form highly functionalized five-, six-, seven-, and eight-membered rings in modest to good yields.
Medical Requirements of the Hospital Pharmacy

Before the medical requirements of a hospital pharmacy are considered, it is important to have a clear understanding of the function of hospitals. It is generally recognized that a hospital has four primary purposes: The diagnosis of disease. The treatment of the patient. The teaching of doctors, nurses and medical students. 4. Research. DIAGNOSIS OF DISEASE As regards the diagnosis of disease, the clinician and the diagnostic laboratories are alone concerned, but as regards the other three functions of the hospital the pharmacy often has an important role. It is my plan to discuss the relationship of the pharmacy to these three important purposes of the hospital. TREATMENT OF THE PATIENT As regards the first of these, namely, the treatment of the patient, the role of the pharmacy is distinctly important. Therapeutic results depend in large measure on the pharmacy's dispensing exactly what is ordered. The physician
Differential current switch logic: a low power DCVS logic family

Differential current switch logic (DCSL), a new logic family for implementing clocked CMOS circuits, has been developed. DCSL is in principle a clocked differential cascode voltage switch logic circuit (DCVS). The circuit topology outlines a generic method for reducing internal node swings in clocked DCVS logic circuits. In comparison to other forms of clocked DCVS, DCSL achieves better performance both in terms of power and speed by restricting internal voltage swings in the NMOS tree. DCSL circuits are capable of implementing high complexity high fan-in gates without compromising gate delay. Automatic lock-out of inputs on completion of evaluation is a novel feature of the circuit. Three forms of DCSL circuits have been developed with varying benefits in speed and power. SPICE simulations of circuits designed using the 1.2 /spl mu/m MOSIS SCMOS process indicate a factor of two improvement in speed and power over comparable DCVS gates for moderate tree heights.
Laser-frequency stabilization using mode interference from a reflecting reference interferometer.

We present a new method for locking the frequency of a laser to a reference-interferometer cavity. For a non-mode-matched input beam, the light reflected off a cavity contains an interference between the wave fronts corresponding to the various cavity modes. A detector placed at the proper position on the interference pattern provides a signal proportional to the imaginary component of the reflected field. As a function of laser frequency, this signal is dispersion shaped and can be used as the error signal for electronic frequency stabilization.
Discovery of yttrium, zirconium, niobium, technetium, and ruthenium isotopes

Abstract Currently, thirty-four yttrium, thirty-five zirconium, thirty-four niobium, thirty-five technetium, and thirty-eight ruthenium isotopes have been observed and the discovery of these isotopes is described here. For each isotope a brief synopsis of the first refereed publication, including the production and identification method, is presented.
Transient Signal Distortion In A Multipath Environment

Abstract : The classification of transient signals is facilitated if propagational distortion is removed. This distortion can be removed if the ocean impulse response from source to receiver is known. The ocean impulse response is, however, very sensitive to source location and the ocean environment. It is shown that for a bottom-mounted receiver and almost normal incidence, distortion of a 244-Hz transient signal envelope can be accounted for if the time delays and relative amplitudes of the ocean impulse response are accurately known. These time delays and amplitudes are extracted from transient data for the known source case. This work provides the motivation for the development of high-resolution, time-delay estimation algorithms to be presented in a companion paper. These algorithms will be tested on the data presented in this paper for the unknown source case.
Options For Upgrading Legacy Avionics Systems

This paper examines a comprehensive set of options for upgrading legacy avionics systems in tactical aircraft. The options have been developed as part of study involving the avionics system of a current military aircraft. Multiple options are considered ranging from minor changes to the legacy system to complete replacement of computers and communications buses with commercial off-the-shelf (COTS) hardware and new software. The pros and cons of each potential solution are described and guidelines are given for choosing the appropriate solution for a given program. The results of this study may be used when evaluating upgrade options for a wide range of embedded computer applications.
Analytic models of plausible gravitational lens potentials

Gravitational lenses on galaxy scales are plausibly modelled as having ellipsoidal symmetry and a universal dark matter density profile, with a Sersic profile to describe the distribution of baryonic matter. Predicting all lensing effects requires knowledge of the total lens potential: in this work we give analytic forms for that of the above hybrid model. Emphasising that complex lens potentials can be constructed from simpler components in linear combination, we provide a recipe for attaining elliptical symmetry in either projected mass or lens potential. We also provide analytic formulae for the lens potentials of Sersic profiles for integer and half-integer index. We then present formulae describing the gravitational lensing effects due to smoothly-truncated universal density profiles in cold dark matter model. For our isolated haloes the density profile falls off as radius to the minus fifth or seventh power beyond the tidal radius, functional forms that allow all orders of lens potential derivatives to be calculated analytically, while ensuring a non-divergent total mass. We show how the observables predicted by this profile differ from that of the original infinite-mass NFW profile. Expressions for the gravitational flexion are highlighted. We show how decreasing the tidal radius allows stripped haloes to be modelled, providing a framework for a fuller investigation of dark matter substructure in galaxies and clusters. Finally we remark on the need for finite mass halo profiles when doing cosmological ray-tracing simulations, and the need for readily-calculable higher order derivatives of the lens potential when studying catastrophes in strong lenses.
On bundles that admit fiberwise hyperbolic dynamics

This paper is devoted to rigidity of smooth bundles which are equipped with fiberwise geometric or dynamical structure. We show that the fiberwise associated sphere bundle to a bundle whose leaves are equipped with (continuously varying) metrics of negative curvature is a topologically trivial bundle when either the base space is simply connected or, more generally, when the bundle is fiber homotopically trivial. We present two very different proofs of this result: a geometric proof and a dynamical proof. We also establish a number of rigidity results for bundles which are equipped with fiberwise Anosov dynamical systems. Finally, we present several examples which show that our results are sharp in certain ways or illustrate necessity of various assumptions.
Mechanics of Indentation into Micro- and Nanoscale Forests of Tubes, Rods, or Pillars

The force-depth behavior of indentation into fibrillar-structured surfaces such as those consisting of forests of micro- or nanoscale tubes or rods is a depth-dependent behavior governed by compression, bending, and buckling of the nanotubes. Using a micromechanical model of the indentation process, the effective elastic properties of the constituent tubes or rods as well as the effective properties of the forest can be deduced from load-depth curves of indentation into forests. These studies provide fundamental understanding of the mechanics of indentation of nanotube forests, showing the potential to use indentation to deduce individual nanotube or nanorod properties as well as the effective indentation properties of such nanostructured surface coatings. In particular, the indentation behavior can be engineered by tailoring various forest features, where the force-depth behavior scales linearly with tube areal density (m, number per unit area), tube moment of inertia (I), tube modulus (E), and indenter radius (R) and scales inversely with the square of tube length (L 2), which provides guidelines for designing forests whether to meet indentation stiffness or for energy storage applications in microdevice designs.
Theoretical study of factors influencing arc erosion of cathode

A theoretical model has been formulated describing the influence of the arc condition and the cathode material and geometry on arc cathode erosion. To arrive at a self-consistent description for the entire arc cathode attachment region, a realistic, one-dimensional sheath model has been used. This sheath model is supplemented by an integral energy balance of the ionization zone between the sheath and the arc, and by a differential energy balance of the cathode. For the case of a tungsten cathode, it has been shown that arc constriction has a strong effect on the current density at the cathode spot but little influence on the cathode temperature. It has also been found that heat conduction within the cathode and radiation from the cathode surface control the energy transport from the cathode spot at low currents, and dissipation by thermionic electron release dominates at high currents. The conclusions are that for high-current applications erosion can be minimized by using a cathode material with a low vapor pressure, and that for these conditions the thermal design of the cathode plays a secondary role. In contrast, for low currents the erosion will be determined by the thermal characteristics of the cathode material. >
Pharmacokinetics and pharmacodynamics of single-chain recombinant human follicle-stimulating hormone containing the human chorionic gonadotropin carboxyterminal peptide in the rhesus monkey☆

Abstract Objective: To compare the pharmacokinetics of a long-acting FSH analog containing the hCG-β carboxyterminal peptide (recombinant hFSH–CTP) with native recombinant hFSH and describe the pharmacodynamics of recombinant hFSH–CTP after SC injection in female rhesus monkeys. Design: Rhesus monkey study. Setting: Academic research environment. Animal(s): Ten female rhesus monkeys. Intervention(s): Recombinant hFSH and recombinant hFSH–CTP were administered via a single SC or IV dose to rhesus monkeys, and serial phlebotomy was performed (n = 2 and n=4 for SC recombinant hFSH and recombinant hFSH–CTP, respectively; for IV dosing, n=1 in each group). An additional two monkeys were pretreated with SC ganirelix and received SC recombinant hFSH–CTP after confirmation of pituitary suppression. Main Outcome Measure(s): Plasma disappearance rate of recombinant hFSH and recombinant hFSH–CTP and serum estradiol levels. Result(s): The elimination half-life of recombinant hFSH–CTP was twofold and fourfold longer than that for recombinant hFSH after SC and IV dosing, respectively. The absorption half-life was approximately threefold longer for recombinant hFSH–CTP than for recombinant hFSH after SC administration. Recombinant hFSH–CTP stimulates estradiol secretion for 5–7 days after an isolated SC dose. Conclusion(s): Addition of the hCG-β carboxyterminal peptide to hFSH-β results in an FSH analog with longer absorption and elimination half-lives compared with native hormone. This analog is capable of prolonged ovarian stimulation in rhesus monkeys after an isolated SC injection.
Anomalous transport due to long-lived fluctuations in plasma Part 1. A general formalism for two-time fluctuations

A general formalism for describing two-time fluctuations in magnetized plasma is presented. Two-time expectations of one-body operators (phase functions) are written in terms of the phase space density autocorrelation function where δ N is the fluctuation in the singular Klimontovich microdensity. It is shown that is the first member of a set of two-time quantities which collectively obeys the linearized BBGKY cumulant hierarchy in the ( X i , t ) variables, with initial conditions successively smaller in the plasma parameter . We study in detail the case of fluctuations in thermal equilibrium, although the general formalism holds also for the non-equilibrium case. To lowest order in e P , Γ obeys the linearized Vlasov equation. From this are recovered all of Rostoker's results for fluctuations excited by Cherenkov emission and absorbed by Landau damping, as well as a constructive proof of the test particle superposition principle. To first order, Γ obeys (in the Markovian approximation) the linearized Balescu-Guernsey-Lenard equation. For frequencies and wavenumbers in the hydrodynamic regime, the velocity moments of Γ obey linearized fluid equations with classical transport coefficients (i.e. essentially those computed by Braginskii in the 3-D case). It has been found that the classical theory is in disagreement with certain computer and laboratory experiments performed in strong magnetic fields. This defect is attributed to the absence in the classical theory of contributions to the collision operator, hence transport coefficients, of fluctuations long-lived on the Vlasov scale. Analogous difficulties arise in the theory of hydrodynamics in neutral fluids. To improve the plasma theory, a renormalization of the two-time hierarchy is proposed which sums selected terms from all orders in e P and thus treats the hydrodynamic fluctuations self-consistently. The resulting theory retains appropriate fluid conservation laws, thereby avoiding erroneous results encountered in certain diffusing orbit theories, when the fluid viscosity is indiscriminantly replaced by the test particle diffusion coefficient. In order to explain the results of the computer simulations, the theory is applied in part 2 to the problem of anomalous hydrodynamic contributions to the transport coefficients.
An Electrically Driven Impinging Liquid Jet for Direct Cooling of Heated Surfaces

An electrically driven impinging liquid jet concept is being proposed and numerically investigated for direct cooling of heated surfaces. The liquid jet flow is generated with the aid of uniquely designed electrodes immersed in a liquid bath and positioned nearby a heated surface. The jet flow is generated based on the electric conduction phenomenon. This numerical study reveals that high impinging jet velocities can be generated with the proposed electrode design, allowing for the effective removal of the heat from the heated surfaces.
Microwave remote sensing of soil moisture for estimation of soil properties

Surface soil moisture dynamics was derived using microwave remote sensing, and employed to estimate soil physical and hydraulic properties. The L-band ESTAR radiometer was employed in an airborne campaign over the Little Washita watershed, Oklahoma during June 10-18, 1992. Brightness temperature (TB) data were employed in a soil moisture inversion algorithm which corrected for vegetation and soil effects. Analyses of spatial TB and soil moisture dynamics during the dry-down period revealed a direct relationship between changes in TB, soil moisture and soil texture. Extensive regression analyses were carried out which yielded statistically significant quantitative relationships between ratio of percent sand to percent clay (RSC, a term derived to quantify soil texture) and saturated hydraulic conductivity (Ksat) in terms of change components of TB and surface soil moisture. Validation of results indicated that both RSC and Ksat can be estimated with reasonable accuracy. These findings have potential applications for deriving spatial distributions of RSC and Ksat over large areas.
Technologies for security, military police, and professional policing organizations: the Department of Energy perspective

There are many technologies emerging from this decade that can be used to help the law enforcement community protect the public as well as public and private facilities against ever increasing threats to this country and its resources. These technologies include sensors, closed circuit television (CCTV), access control, contraband detection, communications, control and display, barriers, and various component and system modeling techniques. This paper will introduce some of the various technologies that have been examined for the Department of Energy that could be applied to various law enforcement applications. They include: (1) scannerless laser radar; (2) next generation security systems; (3) response force video information helmet system; (4) access delay technologies; (5) rapidly deployable intrusion detection systems; and (6) cost risk benefit analysis.
Herbivory-induced mortality increases with radial growth in an invasive riparian phreatophyte

†Background and Aims Under equal conditions, plants that allocate a larger proportion of resources to growth must do so at the expense of investing fewer resources to storage. The critical balance between growth and storage leads to the hypothesis that in high-resource environments, plants that express high growth rates are more susceptible to episodic disturbance than plants that express lower growth rates. †Methods This hypothesis was tested by measuring the radial growth, basal area increment (BAI) and carbon isotope ratios (d 13 C) in tree-ring a-cellulose of 62 mature tamarisk trees (Tamarix spp.) occurring at three sites in the western USA (n ¼ 31 live and 31 killed trees across all sites, respectively). All of the trees had been subjected to periods of complete foliage loss by episodic herbivory over three or more consecutive growing seasons by the tamarisk leaf beetle (Diorhabda carinulata), resulting in approx. 50 % mortality at each site. †Key Results Mean annual BAI (measured from annual ring widths) in the 10 years prior to the onset of herbivory was on average 45 % higher in killed trees compared with live trees (P , 0.0001). Killed trees that had higher growth rates also expressed higher (less negative) d 13 C ratios compared with live trees. In fact, at one site near Moab, UT, the mean annual BAI was 100 % higher in killed trees despite having about a 0.5 ‰ higher d 13 C relative to live trees (P ¼ 0.0008). Patterns of d 13 C suggest that the intrinsic water-use efficiency was higher in killed than surviving trees, possibly as a consequence of lower whole-canopy stomatal conductance relative to live trees. †Conclusions The results show that a likely trade-off occurs between radial growth and survival from foliage herbivory in Tamarix spp. that currently dominates riparian areas throughout the western USA and northern Mexico. Thus, herbivory by D. carinulata may reduce the overall net primary productivity of surviving Tamarix trees and may result in a reduction in genetic variability in this dominant invasive tree species if these allocation patterns are adaptive.
The first example of a nitrogen-substituted oxyallyl cation cycloaddition

The readily available α,α'-phthalimidoyldibromide 2 has been converted to the first reported N-substitutedoxyallyl cation by treatment with either CF3CH2OH or 3M LiClO4Et2O in the presence of Et3N. The formation of this reactive intermediate has been demonstrated by its in situ cycloaddition with cyclopentadiene and furan.
Flow Boiling Heat Transfer to a Dielectric Coolant in a Microchannel Heat Sink

This paper presents an experimental study of flow boiling heat transfer in a microchannel heat sink. The dielectric fluid Fluorinert FC-77 is used as the boiling liquid after it is fully degassed. The experiments were performed at three flow rates ranging from 30-50ml/min. The heat transfer coefficients, as well as the critical heat flux (CHF), were found to increase with flow rate. Wall temperature measurements at three locations (near the inlet, near the exit, and in the middle of heat sink) reveal that wall dryout first occurs near the exit of the microchannels. The ratio of heat transfer rate under CHF conditions to the limiting evaporation rate was found to decrease with increasing flow rate, asymptotically approaching unity. Predictions from a number of correlations for nucleate boiling heat transfer in the literature are compared against the experimental results to identify those that provide a good match. The results of this work provide guidelines for the thermal design of microchannel heat sinks in two-phase flow
Ruthenium‐Catalyzed Oxidative Transformations of Terminal Alkynes to Ketenes By Using Tethered Sulfoxides: Access to β‐Lactams and Cyclobutanones

The oxidation of in situ generated Ru vinylidenes to ketenes is realized with tethered sulfoxides. The result is a Ru-catalyzed oxidative transformation of terminal alkynes to highly valuable ketenes. Moreover, the ketenes generated here were shown to undergo characteristic ketene [2+2] cycloaddition reactions with tethered alkenes and external imines, yielding synthetically versatile bicyclic cyclobutanones and β-lactams, respectively.