cssi/SciSciGPT-SciSciNet huggingface dataset:
Soret feedback in thermal diffusion of suspensions

We have theoretically studied the interaction of a light beam with liquids containing absorbing nanoparticles. We have shown that the Soret effect ensures a feedback that essentially limits heat insertion into the system and the change in its temperature: the temperature rise on the axis of a Gaussian beam is inversely proportional to the Soret constant. Transverse spatial redistribution of the absorbing particles gives a specific thickness dependence of the transparency of the material. These properties not only play an essential role in the study of light interactions with absorbing solutions, but also can underlie optical methods for measurements of the Soret constant.
The covariant quantum superstring and superparticle from their classical actions

Abstract We develop an approach based on the Noether method to construct nilpotent BRST charges and BRST-invariant actions. We apply this approach first to the holomorphic part of the flat-space covariant superstring, and we find that the ghosts b , c z , which we introduced by hand in our earlier work, are needed to fix gauge symmetries of the ghost action. Then we apply this technique to the superparticle and determine its cohomology. Finally, we extend our results to the combined left- and right-moving sectors of the superstring.
Design and test of a propfan gear system

A propfan gear-system technology development program was undertaken to meet the needs of future geared propfan propulsion systems. The design and initial testing of a prototype, 13,000 hp, counterrotating gear system are described. Emphasis was placed on utilization of modern design techniques and advanced gear and bearing technologies during the design phase of this program. A highly instrumented gear-system test was conducted to verify design calculations. A new gear-system test facility is described that allows simulation of flight-operat ing conditions.
Parton cascade description of heavy-ion collisions at CERN?

There seems to be a general consensus now that a first glimpse of a QGP-like effect has become visible in the beautiful NA50 data on J/{psi} production and the anomalous suppression phenomenon. On the other hand, it is still widely believed that the dynamics of heavy-ion collisions at CERN SPS energy is predominantly governed by soft, non-perturbative physics. This is ironic: after all, it is unlikely that a QGP could be formed if the underlying dynamics were essentially soft, rather than that it requires intense quark-gluon production with sufficient cascade-like reinteractions which drive the matter to large density and equilibrium. Therefore, the author advocates in this contribution that for ultra-relativistic nucleus-nucleus collisions a description based on the pQCD interactions and cascade evolution of involved partons can and should be used, owing to the claim that short-range parton interactions play an important role at sufficiently high beam energies, including CERN energy {radical}s {approx_equal} 20 A GeV. Here mini-jet production which liberates of quarks and gluons cannot be considered as an isolated rare phenomenon, but can occur quite copiously and may lead to complex multiple cascade-type processes.
A Study of the MBE HgTe Growth Process

The MBE growth of HgTe on CdTe is examined over a hundred-fold range in Hg/Te2 flux ratio and over four separate substrate surface orientations [(111)Te, (111)Te-4 degrees, (112)Te and (001)]. The 77K Hall mobility of the (112)Te and (001) oriented HgTe layers approaches the best bulk values reported to date, although our (111)Te and (111)Te-4 deg oriented HgTe films yield much lower values. The growth process is shown to be very far from thermodynamic equilibrium at our optimal substrate temperature and calculated equivalent Hg beam pressure. Important clues to help understand the kinetics governing the HgTe growth process are uncovered by studying the defects that form under Hg- or Te-rich conditions with cross-sectional transmission electron microscopy (XTEM). Since multilayered structures are an important application for MBE growth of Hg-based semiconductors, we have also examined the interfacial roughness present in HgTe-CdTe superlattices (SL) as a function of growth orientation.
A Search for Early Optical Emission at Gamma-Ray Burst Locations by the Solar Mass Ejection Imager (SMEI)

The Solar Mass Ejection Imager (SMEI) views nearly every point on the sky once every 102 minutes and can detect point sources as faint as R approx. 10th magnitude. Therefore, SMEI can detect or provide upper limits for the optical afterglow from gamma-ray bursts in the tens of minutes after the burst when different shocked regions may emit optically. Here we provide upper limits for 58 bursts between 2003 February and 2005 April.
Theory of Nuclear Level Density

We have compared the level density of a nuclear model deduced from a statistical analysis with the results of the exact counting of the levels of the same model. The tables of levels of ${\mathrm{Ne}}^{20}$ given by Critchfield and Oleksa have been used as a test of the statistical theory. A new derivation of the level density is presented. It starts, as usual, from the independent-particle model. However, it differs from the previous treatments in two respects: (a) the exact states of the nucleons in the central potential are kept throughout the calculations instead of being replaced by a continuous distribution; (b) the effect of mutual interactions of the nucleons of the Majorana, Bartlett, or Heisenberg type is taken into account in the long-range approximation. With these modifications, the statistical theory agrees very well with the exact counting of the levels, both for the total density and for the density of the levels having a given angular momentum. It is shown that the replacement of the nucleon states by a continuous distribution introduced in most previous derivations, and the neglect of the Majorana forces can produce very large errors. An interpretation is presented of the distribution of angular momentum among nuclear levels in terms of rotations of the whole nucleus as a rigid body.
Fluorescent visualization of a spreading surfactant

The spreading of surfactants on thin films is an industrially and medically important phenomenon, but the dynamics are highly nonlinear and visualization of the surfactant dynamics has been a long-standing experimental challenge. We perform the first quantitative, spatiotemporally resolved measurements of the spreading of an insoluble surfactant on a thin fluid layer. During the spreading process, we directly observe both the radial height profile of the spreading droplet and the spatial distribution of the fluorescently tagged surfactant. We find that the leading edge of a spreading circular layer of surfactant forms a Marangoni ridge in the underlying fluid, with a trough trailing the ridge as expected. However, several novel features are observed using the fluorescence technique, including a peak in the surfactant concentration that trails the leading edge, and a flat, monolayer-scale spreading film that differs from concentration profiles predicted by current models. Both the Marangoni ridge and the surfactant leading edge can be described to spread as R∝tδ. We find spreading exponents δH≈0.30 and δΓ≈0.22 for the ridge peak and surfactant leading edge, respectively, which are in good agreement with theoretical predictions of δ=1/4. In addition, we observe that the surfactant leading edge initially leads the peak of the Marangoni ridge, with the peak later catching up to the leading edge.
Thyroid hormone action on skin.

Purpose of review To review the current understanding regarding thyroid hormone action on skin. To provide a historical context for the recent findings. Recent findings Although direct thyroid hormone actions have been demonstrated on multiple aspects of cutaneous biology, rigorous study remains scant. Still, there is a slowly evolving literature supporting the concept that thyroid hormone can directly stimulate epidermis, dermis, and hair. That action may be accessed to treat cutaneous disease. Summary Here, we review the literature regarding thyroid hormone action on skin along with skin manifestations of thyroid disease. We provide context for more recent findings of direct thyroid hormone stimulation of cutaneous cell proliferation in vitro and in vivo which may portend the use of thyroid hormone to treat cutaneous pathologies.
Tissue- and organ-selective biodistribution of NIR fluorescent quantum dots

A significant portion of the field of nanomedicine is predicated on being able to target nanoparticles to sites of disease. However, in vivo biodistribution and clearance of nanoparticles are poorly understood. In this study, a novel formulation of near-infrared fluorescent InAs(ZnS) quantum dots was synthesized and coated with a systematically increasing chain length of PEG. We found that varying PEG chain length resulted in major changes in organ/tissue-selective biodistribution and clearance from the body.
Stereoselective one-pot synthesis of vinylsilanes from aromatic aldehydes

Abstract Vinylsilanes serve as convenient vinyl anion equivalents, but procedures for their stereoselective synthesis from aldehydes are scarce. A variety of aromatic aldehydes are converted to the corresponding vinylsilanes in a one-pot procedure involving the addition of (trimethylsilylmethyl)lithium to the aldehyde followed by treatment with Cp2TiCH2·AlMe2Cl (‘Tebbe's reagent’). Halide and alkoxide substituents are tolerated, and (E)-vinylsilanes are formed exclusively in good yield.
Complete transverse representation of a correlation singularity of a partially coherent field

An understanding of correlation singularities is fundamentally important in imaging science. Until now spatial coherence studies have examined a two-dimensional projection of the four-dimensional correlation function, finding so-called correlation vortices or correlation ring dislocations in a given transverse plane. Here we describe the properties and symmetries of the full four-dimensional correlation function. The general solution is found to be a hyperbola in two reduced dimensions. For perfect coherence this reduces to crossed straight lines, whereas in the incoherent limit it reduces to parallel lines. These results elucidate a number of previous experimental and theoretical observations regarding correlation singularities and suggest other behaviors of such singularities.
Joseph A. Vita, MD, 1956–2014

On November 2, 2014, our friend and colleague, Joseph Vita, died after a short but gallant struggle with lung cancer at the age of 58. Joe was never a smoker and typically appeared 10 years younger than his age; thus, it was particularly shocking to many when he became ill so suddenly and in his prime. He will be sorely missed; his contributions to cardiovascular medicine were many and diverse. He was a brilliant investigator, a superb clinician, an outstanding mentor, and an expert journal editor. Joseph Vita was born in Fort Rucker, AL, on March 8, 1956. He received his undergraduate education at Yale University, graduating summa cum laude with a major in chemistry. A true Renaissance man, Joe was recruited by Yale to play football, but, instead, used his “spare” time to enroll in philosophy classes and to sing bass for Yale’s storied a capella group, the Whiffenpoofs. He attended medical school at the Columbia University College of Physicians and Surgeons, where he also remained to complete internal medicine training at Columbia Presbyterian Hospital, eventually serving as chief medical resident. In 1986, Joe left Columbia for Brigham and Women’s Hospital to complete his cardiology fellowship and to train as an interventional cardiologist. It was during this time that Joe developed his love for research and put his interventional skills to work performing some of the first intracoronary endothelial function studies …
Addition of allylindium reagents to acyl phosphonates: synthesis of tertiary α-hydroxy alkylphosphonates

Treatment of acyl phosphonates with allylindium reagents in the presence of acetic acid afforded the corresponding α-hydroxy alkylphosphonates in good yields under mild conditions.
Efficient model-checking of dense-time systems with time-convexity analysis

To overcome the sky-rocketing verification cost of embedded software, symbolic model-checking technology of dense-time automata has been proposed as an automated solution. The construction of a timed precondition is a central component in the technology. The general formulation for a timed precondition operator needs to check the continuity of time progress and usually results in high complexity in the construction. However, when the state space characterized by the path condition is convex, we can use a more efficient convex timed precondition operator. In this work, we discuss the concept of time-convexity that allows us to relax the restrictions on the application of the convex timed precondition operator in place of the general one. We present examples in model-checking that engender a non-time-convex space of time progress. Nevertheless, we have also identified a class of timed computation tree logic (TCTL) formulas that only characterize time-convex state spaces. This class includes several important types of TCTL formulas, including some timed inevitabilities with deadlines. We then present a new formulation for the efficient evaluation of general timed inevitabilities with non-time-convex path conditions. The new formulation also leads to a new technique for the approximate evaluation of timed inevitabilities with better precision. Finally, we report our implementation and experiments.
Self-Similarity for Data Mining and Predictive Modeling - A Case Study for Network Data

Recently there are a handful study and research on observing self-similarity and fractals in natural structures and scientific database such as traffic data from networks. However, there are few works on employing such information for predictive modeling, data mining and knowledge discovery. In this paper we study, analyze our experiments and observation of self-similar structure embedded in Network data for prediction through Self Similar Layered Hidden Markov Model (SSLHMM). SSLHMM is a novel alternative of Hidden Markov Models (HMM) which proven to be useful in a variety of real world applications. SSLHMM leverage HMM power and extend such capability to self-similar structures and exploit this property to reduce the complexity of predictive modeling process. We show that SSLHMM approach can captures self-similar information and provides more accurate and interpretable model comparing to conventional techniques.
A Review of Computational Ceramic Armor Modeling

Computational ceramic armor models are reviewed, with an emphasis on a historical perspective. Some discussion concerning the current state of the art is provided, including a summary of issues concerning the strength of in-situ comminuted ceramic.
Rhodium catalyzed C–H olefination of N-benzoylsulfonamides with internal alkenes

An annulation via tandem rhodium catalyzed C–H olefination of N-benzoylsulfonamides with internal olefins followed by C–N bond formation is disclosed. A N-substituted quaternary center is formed during the reaction thus providing efficient access to a series of 3,3-disubstituted isoindolinones.
Nonexponential decay of reactive intermediates: new challenges for spectroscopic observation, kinetic modeling and mechanistic interpretation

A thermally generated reactive intermediate is generally presumed to consist of a population with a distribution of lifetimes characterized by a single, well-defined parameter, τ. The decay of an instantaneously generated population, whose conversion to products occurred by parallel unimolecular steps, would be expected to be defined by a simple, single-exponential expression: A(t)=A0 exp(−t/τ), where A(t) is the population at time t, and A0 is the population at t=0. In this model, the lifetime is also related to the first-order rate constants, ki, for the unimolecular product-forming steps; specifically τ = (Σiki)−1. The ratio of the products is equal to the ratio of the rate constants for their formation. Given an accurate potential energy surface (PES) for the reaction, one would expect to be able to compute the values of the ki under the specified reaction conditions, and hence both the lifetime of the intermediate and the ratio of products. This simple picture, which has formed the basis for most mechanistic investigation of reactive intermediates, and most kinetic modeling of reactions in which they are involved, has been challenged in recent years by molecular dynamics (MD) simulations, which have predicted that a variety of thermally generated intermediates should exhibit bimodal or even multimodal lifetime distributions. In several cases the shortest lifetime populations have been found to lead to products in a ratio quite different from that for the longer-lived populations, and also quite unlike that expected from RRKM or transition state theory calculations based on the same PES used for the MD simulations. This commentary reviews the origins of this behavior and discusses the challenges of designing experiments to test the predictions. Copyright © 2003 John Wiley & Sons, Ltd.
Highly concentrated catalytic asymmetric allylation of ketones.

We report the catalytic asymmetric allylation of ketones under highly concentrated reaction conditions with a catalyst generated from titanium tetraisopropoxide and BINOL (1:2 ratio) in the presence of isopropanol. This catalyst promotes the addition of tetraallylstannane to a variety of ketones to produce tertiary homoallylic alcohols in excellent yield (80–99%) with high enantioselectivities (79–95%). The resulting homoallylic alcohols can also be epoxidized in situ using tert-butyl hydroperoxide (TBHP) to afford cyclic epoxy alcohols in high yield (84–87%).
Millimeter-wave gyroklystron amplifier experiment using a relativistic electron beam

A fundamental-mode TE/sub 111/ degrees two-cavity intense-beam gyroklystron amplifier experiment, operating at an accelerating voltage of 1 MV, is reported. The two cavities that were tested are designed to serve as bunching cavities for a high-power output cavity. The two-cavity amplifier has demonstrated a linear gain of 15 dB and an unsaturated output power of approximately 40 kW, with the intracavity gain and power approximately 4 dB higher. The frequency of the second cavity has been found to track the frequency of the driven cavity over a range of 300 MHz around a center frequency of 35 GHz. Stable amplifier operation was achieved with beam currents as large as 150 A and a velocity pitch ratio of 0.36. The stable operating range was limited by spurious oscillation in the TE/sub 112/ degrees mode. Theoretical calculations indicate that higher gains might be attainable if this mode could be suppressed. >
Optical tunneling from an on-chip resonator

We experimentally observe light emission from a region that is far away from our on-chip device. We photograph up to 10-µm tunneling distance; this gap is greater than 20% of the device size.
Efficient RAM and Control Flow in Verifiable Outsourced Computation

Recent work on proof-based verifiable computation has resulted in built systems that employ tools from complexity theory and cryptography to address a basic problem in systems security: allowing a local computer to outsource the execution of a program while providing the local computer with a guarantee of integrity and the remote computer with a guarantee of privacy. However, support for programs that use RAM and control flow has been problematic. State of the art systems either restrict the use of these constructs (e.g., requiring static loop bounds), incur sizeable overhead on every step, or pay tremendous costs when the constructs are invoked. This paper describes Buffet, a built system that solves these problems by providing inexpensive “a la carte” RAM and dynamic control flow. Buffet composes an elegant prior approach to RAM with a novel adaptation of techniques from the compilers literature. Buffet allows the programmer to express programs in an expansive subset of C (disallowing only “goto” and function pointers), can handle essentially any example in the verifiable computation literature, and achieves the best performance in the area by multiple orders of magnitude.
Smart Parking Pilot on the Coaster Commuter Rail Line in San Diego, California

Increasingly, public transit authorities are harnessing advances in sensor, payment, and enforcement technologies to operate parking facilities more efficiently. In the short term, these innovations promise to enhance customer parking experiences, increase the effective supply of existing parking with minimal investment, and increase ridership and overall revenue. Over the longer term, these systems could further expand ridership by generating revenue to add parking capacity and improve access. This paper reports on the Smart Parking Pilot Project on the COASTER commuter rail line in San Diego (California, USA), which builds on the transit-based smart parking field test research conducted at the Rockridge San Francisco Bay Area Rapid Transit (BART) District station. The paper begins with a literature review of related parking technology, management and pricing strategies, and the optimization of parking resources at transit facilities. Next, the authors describe results of an initial pilot feasibility study. Finally, the phased smart parking implementation plan, carefully tailored to address key transit-related parking problems at the station and corridor levels, is described along with the pilot project's evaluation criteria.
Linear programming based detectors for two-dimensional intersymbol interference channels

We present and study linear programming based detectors for two-dimensional intersymbol interference channels. Interesting instances of two-dimensional intersymbol interference channels are magnetic storage, optical storage and Wyner's cellular network model. We show that the optimal maximum a posteriori detection in such channels lends itself to a natural linear programming based sub-optimal detector. We call this the Pairwise linear program detector. Our experiments show that the Pairwise linear program detector performs poorly. We then propose two methods to strengthen our detector. These detectors are based on systematically enhancing the Pairwise linear program. The first one, the Block linear program detector adds higher order potential functions in an exhaustive manner, as constraints, to the Pairwise linear program detector. We show by experiments that the Block linear program detector has performance close to the optimal detector. We then develop another detector by adaptively adding frustrated cycles to the Pairwise linear program detector. Empirically, this detector also has performance close to the optimal one and turns out to be less complex then the Block linear program detector.
Measurement of package inductance and capacitance matrices

A technique is presented for the measurement of resistance, inductance, conductance, and capacitance matrices of large pin count electronic packages. Circuit analysis of an assumed lumped model is used to define a measurement technique based on two sets of measurements on specially prepared samples. Formulas are derived for use with network analyzer measurements. Measurements and simulations on a 208-lead quad flat pack show that the method attains good accuracy for all but the small values of the conductance matrix.
Lower extremity fractures in motor vehicle collisions: the role of driver gender and height

In a previous study it was noted that there was a higher incidence of lower-extremity fractures among women drivers. Analyses were based on a linkage between trauma registry and police crash report data. The present study addresses the issue of whether the differences noted are attributed to driver gender or are merely a reflection of differences in driver height. An inverse association was noted between driver height and the incidence of lower-extremity fractures. Those shorter than average (5'7") for this population had a 64% increase in lower-extremity fracture, which can be mainly attributed to ankle/tarsal injuries. Thus, the incidence of these injuries appears to be a function of driver height, with an increase among shorter drivers, most of whom are women.
A Novel Test for Selection on cis-Regulatory Elements Reveals Positive and Negative Selection Acting on Mammalian Transcriptional Enhancers

Measuring natural selection on genomic elements involved in the cis-regulation of gene expression—such as transcriptional enhancers and promoters—is critical for understanding the evolution of genomes, yet it remains a major challenge. Many studies have attempted to detect positive or negative selection in these noncoding elements by searching for those with the fastest or slowest rates of evolution, but this can be problematic. Here, we introduce a new approach to this issue, and demonstrate its utility on three mammalian transcriptional enhancers. Using results from saturation mutagenesis studies of these enhancers, we classified all possible point mutations as upregulating, downregulating, or silent, and determined which of these mutations have occurred on each branch of a phylogeny. Applying a framework analogous to Ka/Ks in protein-coding genes, we measured the strength of selection on upregulating and downregulating mutations, in specific branches as well as entire phylogenies. We discovered distinct modes of selection acting on different enhancers: although all three have experienced negative selection against downregulating mutations, the selection pressures on upregulating mutations vary. In one case, we detected positive selection for upregulation, whereas the other two had no detectable selection on upregulating mutations. Our methodology is applicable to the growing number of saturation mutagenesis data sets, and provides a detailed picture of the mode and strength of natural selection acting on cis-regulatory elements.
Signaling through private equity placements and its impact on the valuation of biotechnology firms

Abstract This paper investigates how young, publicly held technology firms contend with information asymmetry, and the hazards it introduces, to acquire the capital necessary for future growth. We ascribe to the view that firms issuing private equity signal the marketplace that managers believe their growth opportunities are undervalued. Consistent with this view, we find significant positive abnormal returns to announcements of private equity placements. We develop theory suggesting that returns are determined by the timing of previous signals. We also argue that the characteristics of the private placement signal, specifically whether private equity is bundled with research partnerships, influence the strength of the signal. Our results largely support our expectations.
On Efficient Jurisdiction Structures in a Simple Local Public Goods Economy with Interjurisdictional Trade

This note shows that if commodities are tradable across jurisdictions, then it may be efficient to have heterogeneously sized jurisdictions, even if (i) consumers are identical, (ii) there is one private good and one public good, (iii) utility and production functions are not affected by population (within the relevant range of sizes of jurisdictions).
Harmonising Basel III and the Dodd Frank Act through greater collaboration between standard setters and national supervisors

Having considered a vital means whereby the Basel III framework and the Dodd Frank Act could achieve a respectable degree of harmonization, in the paper which precedes this, namely, the paper on “Harmonising Basel III and the Dodd Frank Act through International Accounting Standards – Reasons why International Accounting Standards Should Serve as “Thermostats”, this paper considers another important means of effectively achieving the aims and objectives of these important and major regulatory reforms aimed at achieving greater financial stability. In so doing, it will highlight challenges encountered by the Basel III framework, as well as that encountered by the Dodd Frank Act – particularly in the areas of enforcement, coordination and communication. In facilitating better enforcement, the need for high level principles, bright line rules and a more effective mandate will be emphasized. Furthermore, a system whereby greater collaboration between standard setters and national supervisors can be better facilitated requires effective coordination and communication mechanisms aimed at ensuring that vital decisions and information are communicated timely, accurately, effectively and completely.
Prevention of Urinary Tract Infection

Recurrent UTI remains an exceedingly common clinical problem among women of all ages. Among otherwise healthy premenopausal and postmenopausal women, increased susceptibility to recurrences seems to be conferred by intrinsic host factors, such as nonsecretor genotype or estrogen status, and by exogenous exposures or behaviors, such as use of a diaphragm with spermicide, antimicrobial use, and sexual behavior. The natural history of recurrent UTIs is notable for a temporal clustering phenomenon, the tendency of women to revert to a baseline infection pattern after the cessation of preventive interventions, and repeated serial reinfections of the urinary tract from the fecal reservoir, often by genetically identical organisms. Low-dose antimicrobial regimens given daily, three times weekly, or postcoitally are effective in preventing recurrences in most women with a predisposition to frequent infection. Intermittent patient-initiated self-treatment is an appropriate and effective option in some patients with lower recurrence rates. In postmenopausal women, estrogen replacement therapy, particularly vaginally applied estriol creams, may also significantly reduce the rate of recurrent UTI. Ongoing investigations in the areas of microbial ecology of the vaginal flora, the molecular basis for host-parasite interactions within the urinary tract, and vaccine development may eventually lead to improved means to prevent recurrent urinary tract infections more effectively.
Numerical Simulation of Liquid Jet Atomization Including Turbulence Effects

This paper describes numerical implementation and validation of a newly developed hybrid model, T-blob/T-TAB, into an existing computational fluid dynamics (CFD) program for primary and secondary breakup simulation of liquid jet atomization. This model extends two widely used models, the Kelvin-Helmholtz (KH) instability of Reitz (the "blob" model) (1987, Atomization Spray Technol., 3, pp. 309-337) and the Taylor-Analogy-Breakup (TAB) secondary droplet breakup of O'Rourke and Amsden (1987, SAE Technical Paper No. 872089) to include liquid turbulence effects. In the primary breakup model, the level of the turbulence effect on the liquid breakup depends on the characteristic scales and flow conditions at the liquid nozzle exit. Transition to the secondary breakup was modeled based on energy balance, and an additional turbulence force acted on parent drops was modeled and integrated into the TAB governing equation. Several assessment studies are presented, and the results indicate that the existing KH and TAB models tend to underpredict the product drop size and spray angle, whereas the current model provides superior results when compared to the measured data.
AC electrohydrodynamic instabilities in thin liquid films

When DC electric fields are applied to a thin liquid film, the interface may become unstable and form a series of pillars. In this paper, we apply lubrication theory to examine the possibility of using AC electric fields to exert further control over the size and shape of the pillars. For perfect dielectric films, linear stability analysis shows that the influence of an AC field can be understood by considering an effective DC field. For leaky dielectric films, Floquet theory is applied to carry out the linear stability analysis, and it reveals that high frequencies may be used to inhibit the accumulation of interfacial free charge, leading to a lowering of growth rates and wavenumbers. Nonlinear simulations confirm the results of the linear stability analysis while also uncovering additional mechanisms for tuning overall pillar height and width. The results presented here may be of interest for the controlled creation of surface topographical features in applications such as patterned coatings and microelectronics.
Learning-by-Doing and Its Implications for Economic Growth and International Trade

This paper extends the learning-by-doing model of Alwyn Young (1991), which assumes bounded learning-by-doing in each industry and knowledge spillovers, from two perspectives. First, it introduces physical capital as another factor of production in addition to labor. Second, it takes into account capital accumulation and population growth. This extended model is then used to study the dynamic effects of learning-by-doing in both autarky and two-country free trade situations. The main findings are: 1. Learning-by-doing is the source of sustainable growth in the long-run; 2. In both autarky and free trade situations, an increase in population growth rate or saving rate expedites both the growth rate of Real GDP per capita and technical progress in the long-run; 3. Compared with the autarky situation, under free trade the LDC experiences slower growth rate of per-capita output and slower technical progress, while the situation in DC is just the opposite. In addition, the effects of free trade on intertemporal welfare as well as the implications of a change in population growth rate or saving rate are also discussed based on the conclusions in Young (1991).
IMPERIALISM AND COMPETITION IN ANTHROPOLOGY, SOCIOLOGY, POLITICAL SCIENCE AND ECONOMICS: A PERSPECTIVE FROM DEVELOPMENT ECONOMICS

In work published in the 1980's Yujro Hayami and I elaborated a theory of institutional innovations in which institutional changes are induced, on the demand side, by changes in relative resource endowments and technical change and, on the supply side, by changes in cultural endowments and advances in social science knowledge. In the mid-1980's I initiated a research program to explore what development economists might learn from research by other social scientists working in the field of development. In this paper I draw on this earlier work, and on related literature to explore the conditions under which interdisciplinary imperialism or interdisciplinary collaboration can be most productive. I argue that when the objective of research is to advance fundamental knowledge in the social sciences imperialism can be highly productive. But where multiple sources of knowledge must be drawn on for policy, mechanism, or system design interdisciplinary collaboration is essential.(This abstract was borrowed from another version of this item.)
El Niño and World Primary Commodity Prices: Warm Water or Hot Air?

This paper examines the historical effects of the El Nino-Southern Oscillation (ENSO) cycle on world prices and economic activity. The primary focus is on world real non-oil primary commodity prices, although the effects on G-7 consumer price inflation and GDP growth are also considered. This paper has several distinct advantages over previous studies. First, several econometric models are estimated using fairly broad measures of prices and economic activity. Second, the models include continuous measures of ENSO intensity (sea surface temperature and sea-level air pressure anomalies in the Pacific Ocean) rather than dummy variable measures. Finally, confidence intervals are constructed for all estimated effects of ENSO on world prices and economic activity. The analysis indicates that ENSO has economically important and statistically significant effects on world real commodity prices. A one-standard-deviation positive surprise in ENSO, for example, raises real commodity price inflation about 3.5 to 4 per...
Multiscale modeling of intergranular fracture in aluminum: constitutive relation for interface debonding

Intergranular fracture is a dominant mode of failure in ultrafine grained materials. In the present study, the atomistic mechanisms of grain-boundary debonding during intergranular fracture in aluminum are modeled using a coupled molecular dynamics—finite element simulation. Using a statistical mechanics approach, a cohesive-zone law in the form of a traction–displacement constitutive relationship, characterizing the load transfer across the plane of a growing edge crack, is extracted from atomistic simulations and then recast in a form suitable for inclusion within a continuum finite element model. The cohesive-zone law derived by the presented technique is free of finite size effects and is statistically representative for describing the interfacial debonding of a grain boundary (GB) interface examined at atomic length scales. By incorporating the cohesive-zone law in cohesive-zone finite elements, the debonding of a GB interface can be simulated in a coupled continuum–atomistic model, in which a crack starts in the continuum environment, smoothly penetrates the continuum–atomistic interface, and continues its propagation in the atomistic environment. This study is a step toward relating atomistically derived decohesion laws to macroscopic predictions of fracture and constructing multiscale models for nanocrystalline and ultrafine grained materials.
Feasibility of reconstructing paleoatmospheric records of selected alkanes, methyl halides, and sulfur gases from Greenland ice cores

Seven short-lived atmospheric trace gases were measured in 25 ice core samples from Summit, Greenland. Samples were selected from contemporaneous sections of fluid- and dry-drilled ice cores to examine what effects using n-butyl acetate as the drill fluid would have on the measurements. The gases include three light alkanes, C2H6, C3H6, and n-C4H10; two methyl halides, CH3Cl and CH3Br; and two sulfur compounds, OCS and CS2, with gas ages from 125 to 325 years before present. Alkane levels are comparable to measurements in modern Arctic air, although C2H6 exhibits greater variability than expected compared with C3H6 and n-C4H10. These results are not consistent with the idea that the alkanes are primarily of anthropogenic origin, suggesting that the ice cores may not truly record a paleoatmospheric signal with respect to these gases. The CH3Br results are consistent with previous observations of “excess” CH3Br in Greenland firn air. In situ production processes appear to overwhelm the paleoatmospheric signal of this gas. CH3Cl exhibits the same effect to a lesser extent. OCS levels are similar to those in Antarctic ice cores and appear to reflect paleoatmospheric levels. CS2 results are similar to the limited database of modern atmospheric measurements. Only C3H8 and n-C4H10 exhibit clear evidence of contamination because of the presence of the drill fluid. The results indicate that it is possible to analyze many trace gases in fluid- and dry-drilled ice samples. However, it appears that in situ production may significantly alter the levels of some trace gases in Greenland ice cores.
Model Estimates of the Contributions of Environmental Tobacco Smoke to Volatile Organic Compound Exposures in Office Buildings

Volatile organic compounds (VOC) in office buildings originate from multiple sources, such as outdoor air, building materials, occupants, office supplies, and office equipment. Many of the VOC found in office buildings are also present in environmental tobacco smoke (ETS), e.g., benzene, toluene, formaldehyde. Measurements made to date in Office buildings have been interpreted by some to imply that the contributions to ETS to VOC exposures in office buildings are small. Four different ventilation-infiltration scenarios were modeled for a typical office building. The purpose of this investigation was to provide first-order estimate of the range of contributions of ETS to VOC contributions in office buildings under various ventilation conditions through the use of a mass-balance model and to evaluate the significance of such contributions relative to the VOC concentration measured in office buildings. 25 refs., 1 fig., 4 tabs.
Revisión de la jungla de la teoría administrativa

EN ESTE ARTICULO SE REEXAMINAN LAS DIVERSAS ESCUELAS O ENFOQUES DE LA TEORIA DE LA ADMINISTRACION QUE IDENTIFIQUE HACE CERCA DE DOS DECADAS Y QUE LLAME "LA JUNGLA DE LA TEORIA ADMINISTRATIVA." LO QUE AHORA SE ENCUENTRA SON ONCE ENFOQUES DISTINTOS EN COMPARACION CON LOS SEIS ORIGINALES, LO CUAL IMPLICA QUE LA "JUNGLA" PODRIA ESTARSE HACIENDO MAS DENSA E IMPENETRABLE. SIN EMBARGO, ESTAN OCURRIENDO CIERTOS DESARROLLOS QUE INDICAN QUE PODRIAMOS ESTAR CAMINANDO MAS DE LO QUE LA GENTE PIENSA HACIA UNA TEORIA UNIFICADA Y PRACTICA DE LA ADMINISTRACION.
Assessing the implementation of the chronic care model in quality improvement collaboratives.

The Institute of Medicine's report, Crossing the Quality Chasm: A New Health System for the 21st Century (IOM 2001), has challenged health care practitioners, administrators, and policymakers to implement major reforms to reinvent the nation's health care delivery system. Chronic care quality improvement (QI) collaboratives offer one set of comprehensive strategies for restructuring chronic care delivery systems. The collaboratives combine rapid-cycle change methods with multiple change strategies suggested by the Chronic Care Model (CCM) to facilitate improvements in processes and outcomes of care for people with chronic illness (ICIC 2003a, ICIC 2003b; IHI 2003). The CCM recommends organizational change in six areas: delivery system redesign, patient self-management support, decision support, information support, community linkages, and health system support. While change strategies have been implemented with success in each of the six areas (Wagner, Austin, and Von Korff 1996; Von Korff et al. 1997), little is known about how implementation in all six areas affects processes and outcomes of care (Bodenheimer, Wagner, and Grumbach 2002a,Bodenheimer, Wagner, and Grumbach 2002b). The RAND/Berkeley Improving Chronic Illness Care Evaluation (ICICE) team was charged with assessing the implementation and impact of the chronic care collaboratives. Key objectives were to evaluate (1) the success of the chronic care collaboratives in inducing the changes needed to implement the CCM and (2) the effects on costs, processes, and outcomes of care in organizations which were successful in varying degrees in implementing CCM (Cretin, Shortell, and Keeler 2004). This paper focuses on the first objective by addressing the following question: Did the participating organizations succeed in making CCM changes to their care delivery systems?
On the complexity of quantum ACC

For any q>1, let MOD/sub q/ be a quantum gate that determines if the number of 1's in the input is divisible by q. We show that for any q, t>1, MODP is equivalent to MOD/sub t/ (up to constant depth). Based on the case q=2, C. Moore (1999) has shown that quantum analogs of AC/sup (0)/, ACC[q], and ACC, denoted QAC/sub wf//sup (0)/ QACC[2], QACC respectively, define the same class of operators, leaving q>2 as an open question. Our result resolves this question, proving that QAC/sub wf//sup (0)/=QACC[q] QACC for all q. We also develop techniques for proving upper bounds for QACC in terms of related language classes. We define classes of languages EQACC, NQACC and BQACC/sub Q/. We define a notion of log-planar QACC operators and show the appropriately restricted versions of QACC and BQACC are contained in P/poly. We also define a notion of log-gate restricted QACC operators and show the appropriately restricted versions of QACC and NQACC are contained in TC/sup (0)/. To do this last proof; we show that TC/sup (0)/ can perform iterated addition and multiplication in certain field extensions. We also introduce the notion of a polynomial-size tensor graph and we show that families of such graphs can encode the amplitudes resulting from applying an arbitrary QACC operator to an initial state.
A lower bound on the capacity of wireless erasure networks with random node locations

In this paper, a lower bound on the capacity of wireless ad hoc erasure networks is derived in closed form in the canonical case where n nodes are uniformly and independently distributed in the unit area square. The bound holds almost surely and is asymptotically tight. We assume all nodes have fixed transmit power and hence two nodes should be within a specified distance r n of each other to overcome noise. In this context, interference determines outages, so we model each transmitter-receiver pair as an erasure channel with a broadcast constraint, i.e. each node can transmit only one signal across all its outgoing links. A lower bound of Θ-(nr n ) for the capacity of this class of networks is derived. Finally, the case where the erasure probabilities are themselves random variables, for example due to randomness in geometry or channels, is analyzed. We prove somewhat surprisingly that in this setting, variability in erasure probabilities increases network capacity.
HEBS: Histogram Equalization for Backlight Scaling

In this paper, a method is proposed for finding a pixel transformation function that maximizes backlight dimming while maintaining a pre-specified image distortion level for a liquid crystal display. This is achieved by finding a pixel transformation function, which maps the original image histogram to a new histogram with lower dynamic range. Next the contrast of the transformed image is enhanced so as to compensate for brightness loss that would arise from backlight dimming. The proposed approach relies on an accurate definition of the image distortion which takes into account both the pixel value differences and a model of the human visual system and is amenable to highly efficient hardware realization. Experimental results show that the histogram equalization for backlight scaling method results in about 45% power saving with an effective distortion rate of 5% and 65% power saving for a 20% distortion rate. This is significantly higher power savings compared to previously reported backlight dimming approaches.
Sources of Inefficiency in Kansas Farms

This paper uses two different techniques to measure efficiency in a panel of two hundred multi-product Kansas farms from the period 1984 to 2004. The non-parametric linear programming technique, Data Envelopment Analysis (DEA); and a parametric stochastic frontier approach, a translog production function, are used to calculate and then compare efficiencies measures including pure efficiency, technical, scale and allocative. Production, financial, and demographic variables are used to identify and quantify the causes of inefficiencies. We expect to find variables such as hours of family labor, owned versus rented farm, intensity of production, farmers´ risk attitudes and farmers´ age, significant in explaining farm inefficiency levels in Kansas farms.
Efficient scheduled stabilizing output feedback model predictive control for constrained nonlinear systems

In this note, we present a computationally efficient scheduled output feedback model predictive control (MPC) algorithm for constrained nonlinear systems with large operating regions. We design a set of local output feedback predictive controllers with their estimated regions of stability covering the desired operating region, and implement them as a single scheduled output feedback MPC which on-line switches between the set of local controllers and achieves nonlinear transitions with guaranteed stability. The algorithm is illustrated with a highly nonlinear continuous stirred tank reactor process.