cssi/SciSciGPT-SciSciNet huggingface dataset:
Evaluating Completion Damage in High-Rate, Gravel-Packed Wells

Conoco has completed and tested a series of high rate, gravel-packed oil wells. Analysis of the well test data for the first completion indicated significant formation/completion damage had been caused during the gravel-packing process. Extensive laboratory testing designed to closely simulate the completion procedure was performed in conjunction with detailed completion pressure loss evaluation. The studies identified the LCM pill used during completion operations as the primary source of damage. A new, self-breaking, LCM composition was designed that provided fluid-loss control with minimum formation/completion damage. This LCM system and a number of other design improvements were then used in the field's remaining gravel-packed completions. This paper describes the analysis of well test data and the application of this information to evaluate completion procedures for these high rate, cased-hole, gravel-packed completions. The analysis technique used is unique in that it uses a combination of laboratory, analytical, and operational data to quantify individual components of the total measured pressure drop across the completion. This approach provides a significantly better insight into completion performance than merely stating an overall completion pressure drop, skin value, or well flow efficiency. This systematic analysis of pressure losses resulted in a better understanding of formation damage effects and the factors that influenced them during the completion process. This in turn allowed completion procedures to be modified to target specific areas for improvement.
Magnetic nanoparticles and nanotubes for biomedical applications

Magnetic nanomaterials, especially nanoparticles and nanotubes, are among the most widely used nanomaterials for biomedical applications, and they are also the most promising nanomaterials for clinical treatments. This paper starts with the fundamentals for nanomedicine and magnetic nanomedicine. After discussing the basic requirements for the biomedical applications, the properties and the biomedical applications of magnetic nanoparticles and nanotubes are discussed. Our results indicate that, with suitable functionalization, iron oxide nanomaterials are non-toxic to biological systems, and they are ideal drug carriers which can be remotely controlled by external magnetic fields. At the final part of this paper, the challenges and our approach for targeted drug delivery with controlled release are discussed.
Quantitative Digital Angiography as an Adjunct to the lntraoperative Placement of Endovascular Stents in Congenital Heart Disease

Abstract Clearly identifiable intraoperative landmarks render the placement of intraoperative stents difficult. Preoperative use of quantitative digital angiography helps the surgeon accurately insert endovascular stents intraoperatively. By using defined points of reference, we were able to carefully select the size and lengths of stents before the operation and precisely place these stents in the operating room. Furthermore, we have been able to redilate these stents using the same techniques at subsequent operations. Our results reflect the efficacy of this technique.
The effect of aerodynamic asymmetries on turbomachinery flutter

Abstract In this paper, the effect of aerodynamic asymmetries on the flutter characteristics of turbomachinery blades is investigated. Specifically, the present method is used to study the effect of leading edge blending in loaded and unloaded rotors. The unsteady aerodynamic response of the blades to self-excited vibrations is modeled using a harmonic balance method, which allows one to model the entire wheel using complex periodic boundary conditions and a computational grid spanning a single sector (symmetry group). This reduces the computational and memory requirements dramatically compared to similar time-accurate analyses. It is shown that alternate blending degrades the stability of a loaded rotor whereas it improves the stability of an unloaded rotor. On the other hand, when blends are spaced five blades apart their effect is less pronounced.
Lacan's psychoanalysis, or the figure in the screen*

What can an analyst do, psychoanalytically, on a television program? In its very terms, the question seems an aporia. What, indeed, can be more contrary to the privacy, the intimacy of psychoanalytic work than the publicity, the ostentatiousness of what is called "show business"? How, in spite of this discrepancy of contexts, can an analyst take a psychoanalytic stance on a television screen? It is nothing less than the challenge of this question that Lacan addresses through his enigmatic and ironical performance on the tube. If the written text of this video performance, originally aired on French television (January 1973) as a program named "Psychoanalysis," was from the outset destined to be published, simultaneously, as a book entitled Television, it is, I would suggest, because, confronted with the camera, Lacan invites us not to take "the little screen" for granted, but to rethink through it, provocatively, his complex structure of address. Through the duplicity of title and of medium of transmission, we are in fact invited to attend the very dissonance inscribed in the text of an appearance: a text which, paradoxically enough, fails to appear to the spectator; a text which, to appear as such, demands not just a reader (rather than a viewer), but, specifically, a reading (and, I would insist, a psychoanalytic reading) of the very act of viewing.
THE X-RAY HALO OF CEN X-3

Using two Chandra observations, we have derived estimates of the dust distribution and distance to the eclipsing high-mass X-ray binary Cen X-3 using the energy-resolved dust-scattered X-ray halo. By comparing the observed X-ray halos in 200 eV bands from 2-5 keV to the halo profiles predicted by the Weingartner & Draine interstellar grain model, we find that the vast majority (≈ 70%) of the dust along the line of sight to the system is located within about 300 pc of the Sun, although the halo measurements are insensitive to dust very close to the source. One of the Chandra observations occurred during an egress from eclipse as the pulsar emerged from behind the mass-donating primary. By comparing model halo light curves during this transition to the halo measurements, a source distance of 5.7 ± 1.5 kpc (68% confidence level) is estimated, although we find this result depends on the distribution of dust on very small scales. Nevertheless, this value is marginally inconsistent with the commonly accepted distance to Cen X-3 of 8 kpc. We also find that the energy scaling of the scattering optical depth predicted by the Weingartner & Draine interstellar grain model does not accurately represent the results determined by X-ray halo studies of Cen X-3. Relative to the model, there appears to be less scattering at low energies or more scattering at high energies in Cen X-3.
Confronting Prejudice and Stereotypes: A Teaching Model

ABSTRACT: As the demographics of the workforce continue to change dramatically and the globalization of the marketplace escalates, it becomes increasingly important for employees, managers, and leaders to value differences and to work effectively with people who have various cultures, backgrounds, races, genders, sexual orientations, and languages. The competencies and skills necessary for effectively working across these boundaries do not necessarily come naturally, and it is increasingly essential for organizations to provide opportunities for people to develop the capacity to deal with volatile issues such as diversity, prejudice, and stereotyping. These issues, which lie at the heart of many problematic interpersonal conflicts and systemic dysfunctionalities, are extremely difficult to address in learning situations, whether classroom or boardroom. In this article, we present a management development experience based on the notion that sharing accurate information, developing self awareness, and enhancing the capacity for empathy lead to heightened awareness of the negative consequences of prejudice and stereotyping and quite possibly encourage people to consider adopting more effective attitudes and behaviors. Specifically, we present a conceptual framework upon which diversity education initiatives may be based and a brief activity entitled, “Prejudice in Our Lives,” which has proven very effective in both higher education and management development venues.
Modes of collaboration in modern science: Beyond power laws and preferential attachment

The goal of the study was to determine the underlying processes leading to the observed collaborator distribution in modern scientific fields, with special attention to nonpower-law behavior. Nanoscience is used as a case study of a modern interdisciplinary field and its coauthorship network for 2000–2004 period is constructed from the NanoBank database. We find three collaboration modes that correspond to three distinct ranges in the distribution of collaborators: (1) for authors with fewer than 20 collaborators (the majority) preferential attachment does not hold and they form a log-normal “hook” instead of a power law; (2) authors with more than 20 collaborators benefit from preferential attachment and form a power law tail; and (3) authors with between 250 and 800 collaborators are more frequent than expected because of the hyperauthorship practices in certain subfields. © 2010 Wiley Periodicals, Inc.
Deducing the age of the dense Venus atmosphere

It is shown how crater size-density counts may be used to help constrain the history of the Venus atmosphere, based on the predictions of simple but reasonable models for crater production, surface erosion, and the effects of atmospheric drag and breakup on incident meteors in the Venus atmosphere. In particular, if the atmosphere is young, the old (uneroded) surfaces will have crater densities upward of 0.0001/sq km and a ratio of small (4 km) craters to large (128 km) craters near 1000. If the atmosphere is old and the breakup mechanism is dominant, absolute crater densities on Venus surfaces will be diminished by several orders of magnitude relative to the young atmosphere case. If atmospheric drag is dominant, the absolute crater density will be lowered by perhaps an order of magnitude relative to the young atmosphere case, and the ratio of small to large craters will be reduced to a value near 10 to the 1.5 power. Once a large fraction of Venus surface has been imaged at kilometer resolution, as the VOIR project promises to do, it could be possible to make an early determination of the age of the Venus atmosphere.
Singlet couplings and (0,2) models

We use the quantum symmetries present in string compactification on Landau-Ginzburg orbifolds to prove the existence of a large class of exactly marginal (0,2) deformations of (2,2) superconformal theories. Analogous methods apply to the more general (0,2) models introduced earlier by the present authors, lending further credence to the fact that the corresponding Landau-Ginzburg models represent bona fide (0,2) SCFTs. We also use the large symmetry groups which arise when the worldsheet superpotential is turned off to constrain the dependence of certain correlation functions on the untwisted moduli. This allows us to approach the problem of what happens when one tries to deform away from the Landau-Ginzburg point. In particular, we find that the masses and three-point couplings of the massless E6 singlets related to H1(End(T)) vanish at all points in the quintic Kahler moduli space. Putting these results together, and invoking some plausible dynamical assumptions about the corresponding linear σ-models, we show that one can deform these Landau-Ginzburg theories to arbitrary values of the Kahler moduli.
Applications of minimum-order Wiener modeling to retinal ganglion cell spatiotemporal dynamics

Abstract In a previous paper (Marmarelis et al. , 1986) we presented the concept of minimum-order Wiener (MOW) modeling of continuous-input/spike-output (CISO) systems. The associated MOW methodology aims at obtaining low-order Wiener models for CISO systems of practical interest. The assertion was made that many neurophysiological systems that fall in this class can be studied effectively by the use of this method. We have chosen a sensory system to demonstrate the efficacy of the method with actual experimental data. The response of retinal ganglion cells to spatiotemporal visual stimuli was studied with this approach and a second-order MOW model was obtained. The results appear to corroborate the adequacy of this model in terms of predicting the timing of the output spikes.
Conditions for Building a Community of Practice in an Advanced Physics Laboratory.

We use the theory of communities of practice and the concept of accountable disciplinary knowledge to describe how a learning community develops in the context of an upper-division physics laboratory course. The change in accountable disciplinary knowledge motivates students' enculturation into a community of practice. The enculturation process is facilitated by four specific structural features of the course and supported by a primary instructional choice. The four structural features are ``paucity of instructor time,'' ``all in a room together,'' ``long and difficult experiments,'' and ``same experiments at different times.'' The instructional choice is the encouragement of the sharing and development of knowledge and understanding by the instructor. The combination of the instructional choice and structural features promotes the development of the learning community in which students engage in authentic practices of a physicist. This results in a classroom community that can provide students with the opportunity to have an accelerated trajectory towards being a more central participant of the community of a practice of physicists. We support our claims with video-based observations of laboratory classroom interactions and individual, semistructured interviews with students about their laboratory experiences and physics identity.
Spitzer Detections of New Dust Components in the Outflow of the Red Rectangle

We present Spitzer high spectral resolution IRS spectroscopy of three positions in the carbon-rich outflow of post-asymptotic giant branch star HD 44179, better known as the Red Rectangle. Surprisingly, the spectra show some strong unknown mid-infrared resonances, in the 13-20 μm range. The shape and position of these resonances vary with position in the nebula, and they are not correlated with the polycyclic aromatic hydrocarbon features. We conclude that these features are due to oxygen-rich minerals, located in a region that is believed to be predominantly carbon-rich. We provide possible explanations for the presence of oxygen-rich dust in the carbon-rich outflows. Simple Mg-Fe oxides (Mg1-xFexO) are suggested as carriers of these unidentified features.
The homogenization limit and waveguide gradient index devices demonstrated through direct visualization of THz fields

Electromagnetic homogenization approximation calculates an effective refractive index of a composite material as a weighted average of its components, and has found uses in gradient refractive index and transformation optics devices. However, the utility of the homogenization approximation is hindered by uncertainty in its range of applicability. Harnessing the capability of time-resolved imaging provided by the terahertz polaritonics platform, we determined the dispersion curves of slab waveguides with periodic arrays of holes, and we quantified the breakdown of the homogenization approximation as the period approached the terahertz wavelength and the structure approached the photonic bandgap regime. We found that if the propagation wavelength in the dielectric waveguide was at least two times as large as the Bragg condition wavelength, the homogenization approximation held independent of the detailed geometry, propagation direction, or fill fraction. This value is much less demanding than the estimate of 10:1 often assumed for homogenization. We further used the experimental capabilities to extract the effective refractive index of the photonic crystals in the homogenization approximation limit, and we used this to analyze the predictive strength of analytical formulas. These formulas enabled rapid design of a Luneburg lens and a bi-directional cloak in a waveguide platform without the need for numerical simulations. Movies of terahertz waves interacting with these structures, which were fabricated using femtosecond laser machining, reveal excellent performance. The combination of an analytical formula and confidence in the homogenization approximation will aid in fast design and prototyping of gradient index devices.
Optical Detection of the Hidden Nuclear Engine in NGC 4258

The subparsec masing disk recently found to be orbiting a central mass of ~3.6 × 107 M☉ in the Seyfert/LINER galaxy NGC 4258 (Miyoshi and coworkers) provides the most compelling evidence to date for the existence of a massive black hole in the nucleus of a galaxy. The disk is oriented nearly edge-on, and the X-ray spectrum is heavily absorbed. Therefore, in this galaxy, the optical emission-line spectrum generally exhibited by an active galactic nucleus is perhaps best sought using polarized light: probing for light scattered off material surrounding the central source. New polarimetry of NGC 4258 has uncovered a compact polarized nucleus whose spectrum consists of a faint blue continuum similar to those of unobscured quasars (Fν ∝ ν-1.1), plus broadened (~1000 km s-1) emission lines. The lines are strongly linearly polarized (5%-10%) at a position angle (85° ± 2°) coincident with the plane of the maser disk. This result provides substantiating evidence for a weakly active central engine in NGC 4258 and for the existence of obscuring, orbiting tori, which impart many of the perceived distinctions between various types of active galaxies.
Religion, the New Millennium, and Globalization

It seems we all have survived the passage of the millennium without many visible trials and tribulations. Actually, one could contend that Dionysius Exiguus, the monk who around 525A.D. came up with the A.D. calendar division now in use around the globe, miscalculated and postdated the birth of Jesus by at least four years, in which case our millennial celebrations were actually a few years late.1 Alternatively, one could believe that Dionisius Exiguus was misguided in choosing the Incarnation rather than the Passion and Resurrection of Christ as the anno Domini, in which case we were a few decades early. Or one might follow the Jewish calendar, or the Islamic one, or the Chinese, the Aztec, whichever, in which case the B.C./A.D. convention is meaningless. Or one could be a strict separationist and deem it unconstitutional to imbue our strictly secular calendar conventions with any particular denominational religious meaning and, therefore one would carefully lowercase the B.C./A.D. signs into the religiously neutral b.c.la.c., before and after "our common era." Which, of course, only opens up the question who are the we? Common to whom? Which era are we talking about? We could continue this exercise ad infinitum and ad absurdum. The fact is that most Christian believers, whether pre-millennial, postmillennial, or simply a-millennial accept the fact that only the Father knows the hour and the day and despite all numerology, it may be futile to try to curtail God's freedom by tying the divine eschatological plans to our own secular calendars and human deadlines. Sacred time and secular time are related, for sacred time can only happen within worldly time. But the relationship is not objective or automatic, and therefore believers are compelled to search for God's
Government influence on the process of innovation in Europe and Japan

Abstract A total of 164 innovation projects were sampled in five industries to determine the effect, if any, of government policy on their conduct and outcome. Sixty-six of the projects had at the time of the study achieved commercial success, in the view of the firms involved. Fifty-one were considered failures, while 47 were still underway. Nearly half of the projects had been affected by one or more mechanisms of government policy. There is no indication that this degree of government involvement has either increased or decreased in recent years. There is also no indication that government involvement influenced success or failure, in any way. It does appear, however, that technology has been relatively successful in coping with government regulation in the area of safety, pollution control, etc., since projects affected by these policies were significantly more likely to be successful.
Construction of pyrazolo[3,4-b]pyridines and pyrazolo[4,3-c]pyridines by ring closure of 3-acylpyridine N-oxide tosylhydrazones

3-Acylpyridine N-oxide tosylhydrazones give good overall yields of a mixture of pyrazolo[3,4-b]pyridines and pyrazolo[4,3-c]pyridines when treated with an electrophilic additive and an amine base. (Z)-Hydrazones cyclize readily, while (E)-hydrazones fail to react under the reported conditions. The reaction takes place at room temperature, and moderate regiocontrol over the cyclization can be achieved by varying the electrophile/solvent combination.
Partonic effects in heavy ion collisions at RHIC

Effects of partonic interactions in heavy ion collisions at RHIC are studied in a multiphase transport model (AMPT) that includes both initial partonic and final hadronic interactions. It is found that a large parton scattering cross section is needed to understand the measured elliptic flow of pions and two-pion correlation function.
R&D spillovers through trade in a panel of OECD industries

This paper investigates the significance of Research and Development (R&D) spillovers through intra- and international trade in intermediate goods for productivity growth in a panel of OECD industries during 1973–1994. In the model, four different sources of R&D are identified: R&D conducted in the particular industry itself, R&D conducted in the same industries in other countries, R&D conducted in other domestic industries, and R&D conducted in other foreign industries. I find that among R&D sources the most important contributions to productivity growth come from the domestic R&D efforts. Here, own R&D is important for both domestic innovation and for the productivity catch-up process. Evidence that international R&D spillovers also have significant effects on productivity growth is found to be less robust. My analysis also shows that human capital affects productivity directly as a factor of production.
Analytical evaluation and correction of port loss error in integrating sphere reflectometers

ABSTRACT Incomplete hemispherical irradiation of the sample (or collection of radiation, in the reverse geometry) in an integrating sphere reflectometer is unavoidable due to sample viewing (or illumination) requirements. This means that one measures with nearly hemispherical irradiation and obtains a quantity that is not identical to the hemispherical/directional (or directional/hemispherical) reflectance factor (HDR) of the sample. The assumption that this quantity is identical to the HDR can lead to error in the measurement result, which is not generally corrected for. The error, a.k.a. port loss error, is minimal for comparative measurements of samples with similar reflective properties, but can easily amount to several percent for a diffuse vs. specular comparison and could be even higher for samples that exhibit strong forward scattering. Only a few papers in the literature have dealt with this issue, perhaps due to the existence of other larger sources of error. Our approach to this problem has three elements: (1) establish a definition and set of equations that quantify the error due to incomplete irradiation of the sample due to the presence of the viewing port (port loss uncertainty); (2) develop algorithms and computer models to predict port loss effects for a specular-diffuse sphere coating and specular-diffuse (or more general bi-directional reflectance distribution function (BRDF)) sample; (3) design a technique and instrumentation to allow routine direct measurements of port loss to correct the error; using reference standards such as an Al mirror and a polytetraflouroethylene (PTFE). Keywords : integrating sphere, reflectance, BRDF, uncertainty.
Highly enantioselective reductive cyclization of acetylenic aldehydes via rhodium catalyzed asymmetric hydrogenation.

Catalytic hydrogenation of acetylenic aldehydes 1a−12a using chirally modified cationic rhodium catalysts enables highly enantioselective reductive cyclization to afford cyclic allylic alcohols 1b−12b. Using an achiral hydrogenation catalyst, the chiral racemic acetylenic aldehydes 13a−15a engage in highly syn-diastereoselective reductive cyclizations to afford cyclic allylic alcohols 13b−15b. Ozonolysis of cyclization products 7b and 9b allows access to optically enriched α-hydroxy ketones 7c and 9c. Reductive cyclization of enyne 7a under a deuterium atmosphere provides the monodeuterated product deuterio-7b, consistent with a catalytic mechanism involving alkyne−carbonyl oxidative coupling followed by hydrogenolytic cleavage of the resulting oxametallacycle. These hydrogen-mediated transformations represent the first examples of the enantioselective reductive cyclization of acetylenic aldehydes.
OBSERVED ORBITAL ECCENTRICITIES

For 391 spectroscopic and visual binaries with known orbital elements and having B0-F0 IV or V primaries, we collected the derived eccentricities. As has been found by others, those binaries with periods of a few days have been circularized. However, those with periods up to about 1000 or more days show reduced eccentricities that asymptotically approach a mean value of 0.5 for the longest periods. For those binaries with periods greater than 1000 days their distribution of eccentricities is flat from 0 to nearly 1, indicating that in the formation of binaries there is no preferential eccentricity. The binaries with intermediate periods (10-100 days) lack highly eccentric orbits.
Crystal growth, structural characterization, and magnetic properties of new uranium(IV) containing mixed metal oxalates: Na2U2M(C2O4)6(H2O)4 (M = Mn2+, Fe2+, Co2+, and Zn2+).

A series of new mixed-metal oxalates containing U4+ and divalent transition metal cations, Na2U2M(C2O4)6(H2O)4 (M = Mn2+, Fe2+, Co2+, and Zn2+), were synthesized via a hydrothermal route and structurally characterized by single crystal X-ray diffraction. All of the materials are triclinic, with space group P1. The three-dimensional structure of these isostructural uranates consists of oxalate bridged UO10 and MO6 polyhedra. The U4+ cation is surrounded by five oxalate ligands, while the M2+ cations are bonded to two oxalate ligands and four water molecules. The magnetic susceptibility data of these mixed metal oxalates were measured as a function of temperature and result in a value of the effective magnetic moment of 3.50 μB for U4+ cation in the Zn member, while the total effective moment of the Mn2+, Fe2+, and Co2+ members are 6.01, 5.46, and 5.06 μB, respectively. For all materials, negative Weiss constants were observed revealing that the materials exhibited local antiferromagnetic interactions. The...
BSDEs with terminal conditions that have bounded Malliavin derivative

Abstract We show existence and uniqueness of solutions to BSDEs of the form Y t = ξ + ∫ t T f ( s , Y s , Z s ) d s − ∫ t T Z s d W s in the case where the terminal condition ξ has bounded Malliavin derivative. The driver f ( s , y , z ) is assumed to be Lipschitz continuous in y but only locally Lipschitz continuous in z. In particular, it can grow arbitrarily fast in z. If in addition to having bounded Malliavin derivative, ξ is bounded, the driver needs only be locally Lipschitz continuous in y. In the special case where the BSDE is Markovian, we obtain existence and uniqueness results for semilinear parabolic PDEs with non-Lipschitz nonlinearities. We discuss the case where there is no lateral boundary as well as lateral boundary conditions of Dirichlet and Neumann type.
Captopril inhibits secretin-induced pancreatic bicarbonate output.

Background. Renin-angiotensin systems function at both the organ and systemic levels. Previous studies suggest that angiotensin II (Ang II) stimulates pancreatic secretion in vitro. In contrast, in vivo studies suggest that Ang II inhibits pancreatic secretion. To further assess Ang II's influence on pancreatic secretion, we examined the effect of captopril on secretin-stimulated pancreatic output. Methods. After a 30-min basal period, four conscious dogs with chronic gastric and Herrera pancreatic fistulas received an intravenous bolus of captopril (0.1 mg/kg) followed by a continuous infusion (25 μg/kg/ min). Control studies were performed with volume-and rate-matched saline infusion. After 1 h, secretin infusion was begun at 16 ng/kg/h, doubling the dose every 30 min. Pancreatic juice was analyzed for bicarbonate and protein. A paired t test was used to assess statistical significance. Results. When compared to controls, pancreatic bicarbonate outputs were lower during captopril administration; the difference between captopril and control was statistically significant at the highest secretin dose. Protein outputs also appeared lower during captopril administration, although these differences were not statistically significant. Conclusion. These data suggest that Ang II may augment secretin-induced pancreatic secretion. Further, the data seemingly refute the inhibitory role attributed to Ang II in earlier studies.
NaCu6Se4: A Layered Compound with Mixed Valency and Metallic Properties

A new ternary compound NaCu6Se4 was synthesized from the reaction of Cu in a molten sodium polyselenide flux. The compound crystallizes in trigonal space group R3m with a = 4.0465(3) A and c = 41.493(5) A. The crystal structure contains flat two-dimensional slabs of (1)/∞[Cu6Se4] with a unique structural arrangement, separated by Na cations. The compound contains mixed valency and has a high conductivity of ∼3 × 10(3) S cm(-1) at room temperature, and exhibits increasing conductivity with decreasing temperature, indicating metallic behavior. A small positive thermopower (4-11 μV K(-1) from 300 to 500 K) and Hall effect measurements indicate p-type transport with a carrier concentration of ∼2.8(3) × 10(21) cm(-3) and a hole mobility of ∼8.75 cm(2) V(-1) s(-1) at 300 K. NaCu6Se4 exhibits temperature-independent Pauli paramagnetism.
Windows Scheduling Problems for Broadcast Systems

The windows scheduling problem is defined by the positive integers n, h, and w1, ...,wn. There are n pages where the window wi is associated with page i, and h is the number of slotted channels available for broadcasting the pages. A schedule that solves the problem assigns pages to slots such that the gap between any two consecutive appearances of page i is at most wi slots. We investigate two optimization problems. (i) The optimal windows scheduling problem: given w1, ..., wn find a schedule in which h is minimized. (ii) The optimal harmonic windows scheduling problem: given h find a schedule for the windows wi = i in which n is maximized. The former is a formulation of the problem of minimizing the bandwidth in push systems that support guaranteed delay, and the latter is a formulation of the problem of minimizing the startup delay in media-on-demand systems. For the optimal windows scheduling problem we present an algorithm that constructs asymptotically close to optimal schedules, and for the optimal harmonic windows scheduling problem we show how to achieve the largest known n's for all values of h.
Simple preparation of a helical quinone

Abstract p -Divinylbenzene and p -benzoquinone combine to give a [5]-helicene-bis-quinone. This procedure uses no light and gives a helicene with an interesting functional group. It is notably simple. An enzymatic hydrolysis is used to obtain the quinone optically active.
Measurement And Identification Of Laser-Damage Thresholds In Thin Films

This paper discusses the source and magnitude of uncertainties in the measurement of practical laser-damage thresholds. Damage is defined to be a permanent induced change in a bare or coated optical surface which degrades the merit of the surface with regard to specifications such as scattering, reflection, or transmission. Bulk damage is not treated, and the discussion is limited to tests conducted with laser pulses having wavelengths of 694 nm or 1064 nm and durations less than 100 ns. The measurement of pulse energy, the spatial and temporal profile of the pulse, and determination of the occurrence of damage are described in detail. It is shown that the uncertainty in the measurement of absolute laser-damage thresholds can be as small as 10% and that, within such limits, there is no site-to-site variation of the threshold of optical surfaces.
Soft drug design: general principles and recent applications.

Soft drug design represents a new approach aimed to design safer drugs with an increased therapeutic index by integrating metabolism considerations into the drug design process. Soft drugs are new therapeutic agents that undergo predictable metabolism to inactive metabolites after exerting their therapeutic effect. Hence, they are obtained by building into the molecule, in addition to the activity, the most desired way in which the molecule is to be deactivated and detoxified. In an attempt to systematize and summarize the related work done in a number of laboratories, including ours, the present review presents an overview of the general soft drug design principles and provides a variety of specific examples to illustrate the concepts. A number of already marketed drugs, such as esmolol, remifentanil, or loteprednol etabonate, resulted from the successful application of such design principles. Many other promising drug candidates are currently under investigation in a variety of fields including possible soft antimicrobials, anticholinergics, corticosteroids, β-blockers, analgetics, ACE inhibitors, antiarrhythmics, and others. Whenever possible, pharmacokinetic and pharmacodynamic properties are briefly summarized and compared to those of other compounds used in the same field. © 2000 John Wiley & Sons, Inc. Med Res Rev, 20, No. 1, 58–101, 2000.
Open for Expansion: US Policy and the Purpose for the Internet in the Post–Cold War Era

US Internet governance policy, it has been argued, is a threat to the Internet. Calls persist for the development of a multilateral Internet governance organization where states, especially the United States, play a lessened Internet governance role. Yet, US policymakers continue to resist greater multilateralism in global Internet governance favoring instead multistakeholder governance. Why do US policymakers continue to resist greater multilateralism in global governance of the Internet? Employing the Open Door interpretation of US diplomatic history, I show that, in the post–Cold War era, US policymakers purposed the Internet as a platform for the expansion of American products and political ideals and view greater multilateralism in global Internet governance as a threat to this purpose for the Internet. US policymakers will continue to support the present multistakeholder Internet governance structure that reflects US Internet governance policy preferences. Efforts at greater multilateralism in global governance of the Internet will continue to encounter US resistance unless such efforts incorporate US Internet governance policy preferences.
The Galaxy Octopole Moment as a Probe of Weak-Lensing Shear Fields

In this paper, we introduce the octopole moment of the light distribution in galaxies as a probe of the weak-lensing shear field. While traditional ellipticity estimates of the local shear derived from the quadrupole moment are limited by the width of the intrinsic ellipticity distribution of background galaxies, the dispersion in the intrinsic octopole distribution is expected to be much smaller, implying that the signal from this higher order moment is ultimately limited by measurement noise, and not by intrinsic scatter. We present the computation of the octopole moment and show that current observations are at the regime in which the octopole estimates will soon be able to contribute to the overall accuracy of the estimates of local shear fields. Therefore, the prospects for this estimator from future data sets such as the Advanced Camera for Survey and the Next Generation Space Telescope are very promising.
The Empirical Minimum-Variance Hedge

Decision making under unknown true parameters estimation risk) is discussed along with Bayes' and parameter certainty equivalent (PCE) criteria. Bayes' criterion incorporates estimation risk in a manner consistent with expected utility maximization. The PCE method, which is the most commonly used, is not consistent with expected utility maximization. Bayes' criterion is employed to solve for the minimum-variance hedge ratio. Empirical application of Bayes' minimum-variance hedge ratio is addressed and illustrated. Simulations shoe that discrepancies between prior and sample parameters may lead to substantial differences between Bayesian and PCE minimum-variance hedges.
State-periodic adaptive compensation of cogging and Coulomb friction in permanent-magnet linear motors

This paper focuses on the state-periodic adaptive compensation of cogging and Coulomb friction for permanent-magnet linear motors (PMLMs) executing a task repeatedly. The cogging force is considered as a position-dependent disturbance and the Coulomb friction is non-Lipschitz at zero velocity. The key idea of our disturbance compensation method is to use past information for one trajectory period along the state axis to update the current adaptation law. The new method consists of three different steps: 1) in the first repetitive trajectory, an adaptive compensator is designed to guarantee the l/sub 2/-stability of the overall system; 2) from the second repetitive trajectory and onward, a trajectory-periodic adaptive compensator stabilizes the system; and 3) to make use of the stored past state-dependent cogging information, a search process is utilized for adapting the current cogging coefficient. We illustrate the validity of our state-periodic adaptive cogging and friction compensator by actual PMLM-model-based simulation.
Acylation-cyclization of allenes using acyltetracarbonylcobalt complexes

Abstract Allenes bearing tethered nucleophiles undergo acylation-cyclization on treatment with acylcobalt complexes and base.
Radical Chemistry Based on (+)-cis-Pinononic and (+)-CIS-Pinonic Acids

Abstract A high yield method for the preparation of (+)-cis-pinononic acid starting from the inexpensive (+)-α-pinene has been developed. The capture of the cyclobutyl radical from decarboxylation of (+)-cis-pinononic acid has been investigated. Moreover the radical decarboxylation of (+)-cis-pinonic acid to the corresponding nor-alkane was studied.
Delayed neutrons from fissionable isotopes of uranium, plutonium and thorium☆

Abstract The periods, relative abundances, and absolute yields of delayed neutrons from “fast” fission of six nuclides (235U, 233U, 238U, 240Pu, and 232Th) and thermal fission of three nuclides (235U, 233U, and 239Pu) have been measured. “Godiva,” the bare 235U metal assembly at Los Alamos, was the neutron source. Six exponential periods were found necessary and sufficient for optimum least-squares fit to the data. Despite evident perturbations, general agreement among delayed neutron periods was obtained for all nuclides. Measured absolute total yields in delayed neutrons per fission (for the pure isotopes) are: 235 U : 0·0165 ± 0.0005 239 Pu: 0·0063 ± 0·0003 233 U : 0·0070 ± 0.0004 240 Pu : 0·0088 ± 0.0006 239 U : 0·0412 ± 0.0017 232 Th: 0·0496 ± 0·0020 Representative of general delayed neutron periods (half-lives) and abundances are the 235U fast-fission data: Half-life (sec) Relative abundance 54·51 ± 0·94 0·038 ± 0·003 21·84 ± 0·54 0·213 ± 0·005 6·00 ± 0·17 0·188 ± 0·016 2·23 ± 0·06 0·407 ± 0·007 0·496 ± 0·29 0·128 ± 0·008 0·179 ± 0·017 0·026 ± 0·003 These data have been corroborated in detail by independent period vs. reactivity measurements on the “Godiva” assembly. Period and abundance values for the various nuclides are compared and several mechanisms for perturbation of measured delayed neutron parameters are discussed.
An automatic data generating system for data base simulation and testing

It would seem in this age where much is heard of the "information explosion," the last thing the world needs is an automatic system for the generation of data. And yet, there are many instances in management systems design where such a system is very useful.
Conic display generator using multiplying digital-analog decoders

The need has been recognized for a computer-driven generator which is capable of drawing complex curves without imposing a great burden on the central computer. It has been shown that analog and hybrid techniques offer promise of lifting some of this computational and storage load. Past approaches using these techniques have been limited in speed and in kinds of curves drawn. Roberts has proposed a hybrid analog-digital generator based on homogeneous coordinate mathematics. Such a generator has been designed and built using the wideband multiplying decoder as its basic component.
Real Exchange Rate and Output Variability: The Role of Sticky Prices

The relationships between the degree of price stickiness and the variability of output and the real exchange rate are investigated in an open economy with flexible exchange rates and capital mobility. A critical degree of price inflexibility is shown to exist below which increased inflexibility reduces the variability of output. Also, as prices become more inflexible, the relationship between the variability of the real exchange rate and that of output will be nonmonotonic; that is, as the variability of the real exchange rate increases, the variability of output first declines and then increases.
Assignment of the triplet manifolds of d8 complexes and linear chains via the effects of temperature and magnetic fields on the phosphorescence lifetimes

Abstract Characteristics of the electronic excited states of transition-metal complexes are reviewed. Attention is focussed on the experimental means of identifying the orbital natures of the emitting manifolds. Two new criteria for distinguishing among excited triplet terms are enunciated: (a) the profile of the phosphorescence lifetime vs. the temperature in the range 77−4 K, and (b) the functional dependence of the phosphorescence decay rate on an external magnetic field at ∼ 4 K temperatures. These criteria are applied to the red emission emanating from solid platinum(II) complexes that form linear chains [Pt(2,2′-bipyridine)(CN)2; Pt(2,2′-bipyridine)Cl2] and to Pt(2-phenylpyridine)2 that crystallizes with discrete dimeric units. The origin of the phosphorescence from all three substances is assigned to a 3 d σ ∗ p σ term from a consideration of the criteria given above. The red emission from solutions and rigid glasses of Pt(4,4′-dimethyl-2,2′-bipyridine)(ecda) and Pt(4,7-diphenyl-1,10-phenantroline)(ecda) [ecda = 1-ethoxycarbonyl-1-cyanoethylene-2,2-dithiolate] is reassigned to a 3 d σ ∗ p σ term of a binuclear defect state since the T-dependence criterion does not support the current assignment to a 3MLCT of a monomeric species.
Asymmetric Homologation of Boronic Esters Bearing Azido and Silyloxy Substituents

In the asymmetric homologation of boronic esters with a (dihalomethyl)lithium, substituents that can bind metal cations tend to interfere. Accordingly, we undertook the introduction of weakly basic oxygen and nitrogen substituents into boronic esters in order to maximize the efficiency of multistep syntheses utilizing this chemistry. Silyloxy boronic esters cannot be made efficiently by direct substitution, but a (hydroxymethyl)boronic ester has been silylated in the usual manner. Conversion of alpha-halo boronic esters to alpha-azido boronic esters has been carried out with sodium azide and a tetrabutylammonium salt as phase-transfer catalyst in a two-phase system with water and either nitromethane or ethyl acetate. These are safer solvents than the previously used dichloromethane, which can form an explosive byproduct with azide ion. Boronic esters containing silyloxy or alkoxy and azido substituents have been shown to react efficiently with (dihalomethyl)lithiums, resulting in efficient asymmetric insertion of the halomethyl group into the carbon-boron bond.
Generation of Ultrafast Jets Through the Implosion of a Nested Conical Wire Array

It is shown that in contrast to the electric pulse power driven implosion of a single conical wire array, the implosion of a nested conical wire array with opposite alternate opening angles can lead to the generation of fast jets, with velocities of the order 108 cm/s. This technique can be applied for the supersonic shear flow stabilization of a dense z-pinch, but possibly also for the fast ignition of a pre-compressed dense deuterium–tritium target.
HIGH-RESOLUTION NMR ANALYSIS OF COBALT(III) COMPLEXES WITH 1,8-DIAMINO-3,6-DITHIAOCTANE

Abstract This article summarizes NMR data obtained for cobalt(III) complexes derived from linear and tripodal tetradentate or pentadentate ligands containing nitrogen and/or sulfur donor atoms, and not complexes of large Schiff-base macrocycles, porphyrins or corrins. The review is supplemented with recent NMR work on complexes that had their origin in the laboratories of Professor Busch at a time when the use of NMR spectroscopy as an inorganic structural tool was in its infancy. The more recent capabilities and uses of nuclear magnetic resonance spectroscopy for assisting in metal complex structure assignments and isomeric identification are illustrated by the following work. Cobalt(III) complexes containing the quadridentate ligand 1,8-diamino-3,6-dithiaoctane (eee) were examined by high resolution one and two-dimensional NMR techniques. The spectra acquired using conventional pulse sequences include proton, carbon, DEPT, COSY and heteronuclear correlation. [Co(eee)(NO 2 ) 2 ]Cl and [Co(eee)Cl 2 ]Cl both give rise to carbon-13 spectra which contain only three signals and 1 H-proton spectra which contain a highly pronounced A 2 B 2 pattern. This data is supportive of the symmetrical cis geometry. Assignments in the proton spectra were assisted by the use of the COSY experiment. Carbon-13 signals were assigned by heteronuclear chemical shift spectroscopy. The DEPT spectra confirmed all carbon signals arise from methylene carbons. The study highlights the power of 1 H and 13 C NMR spectroscopic techniques for the structural characterization of inorganic complexes.
Radial transport times at rotating ring-disk electrodes. Limitations on the detection of electrode intermediates undergoing homogeneous chemical reacti

Abstract An expression is derived for the time required to transport a particle generated at a disk electrode to a concentric ring electrode. Experimental verification is given for the minimum transit time, e.g., the time required to transport a particle from the outermost edge of the disk electrode to the innermost edge of the ring electrode. If a disk electrode intermediate undergoes a homogeneous chemical reaction while it is transported to the ring electrode by convective diffusion, its half-life must be at least ~ 1O−2 sec for it to be detected at the ring electrode.