cssi/SciSciGPT-SciSciNet huggingface dataset:
Total Synthesis of (-)-Pseudolaric Acid B

We report a full account of our work toward the total synthesis of pseudolaric acid B (1a), a diterpene acid isolated from the bark of Pseudolarix kaempferi Gordon (pinaceae). Compound 1a is an antifungal and antifertility agent. Furthermore, its capacity for inhibiting tubulin polymerization makes it a potential lead for cancer therapy. Herein, we describe the use of a Ru- or Rh-catalyzed [5 + 2] intramolecular cycloaddition reaction of an alkyne and a vinylcyclopropane for the construction of the polyhydroazulene core of the molecule. Our first unsuccessful strategy for the introduction of the quaternary center based on an epoxide opening with cyanide led to the discovery of a new TBAF-mediated isomerization of a 1,4-diene to a 1,3-diene and a vinylogous eliminative opening of an epoxide to form a dienol. Our second strategy, based on the cyclization of an alkoxycarbonyl radical upon a diene system, succeeded in forming the quaternary center. Detailed studies showed the dependence of this underutilized approach for the synthesis of lactones on substrate structure and reaction conditions. In the late stage of the synthesis, the unique capacity of cerium organometallic reagents to add to a sensitive, sterically hindered ketone was demonstrated. The easy formation of an oxo-bridged derivative was the major hurdle to the completion of the synthesis and showcased the intriguing reactivity of the complex core of the pseudolaric acids.
Phenomenology of Rayleigh-Taylor turbulence.

I analyze the advanced mixing regime of the Rayleigh-Taylor incompressible turbulence in the small Atwood number Boussinesq approximation. The prime focus of my phenomenological approach is to resolve the temporal behavior and the small-scale spatial correlations of velocity and temperature fields inside the mixing zone, which grows as $\ensuremath{\propto}{t}^{2}$. I show that the ``$5/3$''-Kolmogorov scenario for velocity and temperature spectra is realized in three spatial dimensions with the viscous and dissipative scales decreasing in time, $\ensuremath{\propto}{t}^{\ensuremath{-}1/4}$. The Bolgiano-Obukhov scenario is shown to be valid in two dimensions with the viscous and dissipative scales growing, $\ensuremath{\propto}{t}^{1/8}$.
A partially observed poisson process

Abstract Let M be a Poisson random measure on [0, ∞) and let { X ( t ): t e[0,∞)} be an alternating renewal process induced by the probability measures η and μ;i.e., X alternates between the states 1 and 0 with independent sojourns, those in 1 having distribution η and those in 0 having distribution μ. Assume that M and X are independent. Let X * M be the random measure defined by X * M ( A )=∫ A X ( u ) M (d u ). In this paper we study the random measure X * M and its relationship to the processes M and X engendering it. One interpretation is that M is an underlying process of events and X is a screening process that allows or prevents observation of M , so that X * M is the observed process of events. Distributional, structural and asymptotic properties of the random measure X * M are presented. We develop procedures for statistical estimation and filtering for M , based on observations either of both X and X * M or of X * M alone, when M is an ordinary Poisson process. Estimation is of the rate of M ; the filtering results are explicit or recursive calculations of conditional expectations of the form E [ M ( t )¦¢ t , where (¢ s ) is an appropriate observed history. We also treat estimation of the mean measure m of M when m is periodic and of the Levy measure for M when M is additive. Finally, estimation and filtering results are given for X when X is assumed to be Markov; the observed history may be that of X * M alone or that of both M and X * M .
Modeling scalable pattern generation in DNA reaction networks

We have developed a theoretical framework for developing patterns in multiple dimensions using controllable diffusion and designed reactions implemented in DNA. This includes so-called strand displacement reactions in which one single-stranded DNA hybridizes to a hemi-duplex DNA and displaces another single-stranded DNA, reversibly or irreversibly. These reactions can be designed to proceed with designed rate and molecular specificity. By also controlling diffusion by partial complementarity to a stationary, cross-linked DNA, we can generate predictable patterns. We demonstrate this with several simulations showing deterministic, predictable shapes in space.
Super-Giant Glitches and Quark Stars: Sources of Gamma-Ray Bursts?

When a spinning-down neutron star undergoes a phase transition that produces quark matter in its core, a super-giant glitch of the order ΔΩ/Ω ~ 0.3 occurs on timescales from 0.05 s to a few minutes. The energy released is about 1052 ergs and can account for gamma-ray bursts at cosmological distances. The estimated burst frequency, 10-6 yr-1 per galaxy, is in very good agreement with observations. We also discuss the possibility of distinguishing these events from neutron star mergers by observing the different temporal behavior of gravitational waves.
Resistive Switching in Nanogap Systems on SiO2 Substrates

Voltage-controlled resistive switching in various gap systems on SiO2 substrates is reported. The nanoscale-sized gaps are made by several means using different materials including metals, semiconductors, and amorphous carbon. The switching site is further reduced in size by using multiwalled carbon nanotubes and single-walled carbon nanotubes. The switching in all the gap systems shares the same characteristics. This independence of switching on the material compositions of the electrodes, accompanied by observable damage to the SiO2 substrate at the gap region, bespeaks the intrinsic switching from post-breakdown SiO2. It calls for caution when studying resistive switching in nanosystems on oxide substrates, since oxide breakdown extrinsic to the nanosystem can mimic resistive switching. Meanwhile, the high ON/OFF ratio (approximately 10(5)), fast switching time (2 micros, tested limit), and durable cycles show promising memory properties. The observed intermediate states reveal the filamentary nature of the switching.
Thermodynamics of formation of double salts and mixed crystals from aqueous solutions

Abstract This paper describes a chemical model that calculates (solid + liquid) equilibria in the (m1CuCl2 + m2NiCl2)(aq), (m1MgCl2 + m2CrCl3)(aq), (m1(NH4)2SO4 + m2CuSO4)(aq), and (m1(NH4)2SO4 + m2MgSO4)(aq) systems, where m denotes molality at T = 298.15 K. The Pitzer ion-interaction model has been used for thermodynamic analysis of the experimental mixing solutions solubility data, presented in the literature. The thermodynamic functions needed have been calculated and the theoretical solubility isotherms have been plotted. The mixed solution model parameters {θ(MN) and ψ(MNX)} have been chosen on the basis of the compositions of saturated ternary solutions and data on the pure water solubility of the (NH4)2SO4 · CuSO4 · 6H2O and (NH4)2SO4 · MgSO4 · 6H2O double salts. The results of Pitzer ion interaction model-based thermodynamic studies at T = 298.15 K on 62 binary, 82 ternary and eight multicomponent (water + salt) systems where solid phases with a constant stoichiometric composition (simple and double salts) crystallize have been summarized. The values of the pure electrolyte and mixing ion-interaction parameters, which give the best fit of the activity data in binary solutions and of the ternary solutions solubility data are tabulated. Important thermodynamic characteristics (thermodynamic solubility products K sp ∘ ; standard molar Gibbs free energy of reaction Δ r G m ∘ of the synthesis of the double salts from the corresponding simple salts, components of the ternary solutions; and the standard molar Gibbs free energy of formation Δ f G m ∘ ) of the solids crystallizing from the saturated binary and ternary solutions are given. The Δ f G m ∘ values obtained are compared with those available in the literature. The results of thermodynamic simulation of binary and ternary systems at temperatures differing from the standard (273.15 K and 348.15 K) are presented. The model parameterization is tested by comparison of the predicted and the experimental composition of the invariant points in multicomponent solutions (not used in parameterization process). The component activities of the saturated (m1(NH4)2SO4 · CuSO4 + m2(NH4)2SO4 · MgSO4)(aq) and in the mixed crystalline phase were determined and the change of the molar Gibbs free energy of mixing Δ mix G m ∘ ( s ) of crystals was determined as a function of the solid phase composition. It is established that at T = 298.15 K the mixed (NH4)2SO4 · (Cu,Mg)SO4 · 6H2O crystals show positive deviations from the ideal mixed crystals. Values for the integral Gibbs free energy of mixing Δ mix G m ∘ ( s ) and excess Gibbs free energy of mixing Δ G m E ( s ) in crystals calculated by different methods for the 23 ternary systems with co-crystallization of the salt components have been summarized.
Characteristics of a glassy carbon electrode modified in a mixture of osmium tetroxide and hexacyanoruthenate

Abstract Cyclic voltammetry between 900 and - 500 mV vs. SCE at a glassy carbon electrode in a solution containing 1 mM OsO4, 2 mM K4Ru(CN)6, and 0.5 M NaCl at pH 2.0 results in the accumulation of an electroactive film. After 20 cycles at 50 mV s−1 the deposit corresponds to 400 μC cm−2. The film is stable for several days, whether stored at open circuit in a supporting electrolyte or in air. The modified electrode catalyzes the oxidation of As(III); the anodic peak current at about 1.0 V vs. SCE is proportional to concentration. The mediation of the reduction of IrCl2−6 was studied at a modified rotating disk electrode. The charge propagation was rapid, so the reduction was limited by a combination of the cross-reaction rate and the permeation of the substrate into the film. The same behavior was observed when the electrode was prepared from a solution containing Fe(CN)4-6 rather than Ru(CN)4-6.
An efficient, error-bounded approximation algorithm for simulating quasi-statics of complex linkages

Design and analysis of articulated mechanical structures, commonly referred to as linkages, is an integral part of any CAD/CAM system. The most common approaches formulate the problem as purely geometric in nature, though dynamics or quasi-statics of linkages should also be considered. Existing optimal algorithms that compute forward dynamics or quasi-statics of linkages have a linear runtime dependence on the number of joints in the linkage. When forces are applied to a linkage, these techniques need to compute the accelerations of all the joints and can become impractical for rapid prototyping of highly complex linkages with a large number of joints. We introduce a novel algorithm that enables adaptive refinement of the forward quasi-statics simulation of complex linkages. This algorithm can cull away joints whose contribution to the overall linkage motion is below a given user-defined threshold, thus limiting the computation of the joint accelerations and forces to those that contribute most to the overall motion. It also allows a natural trade-off between the precision of the resulting simulation and the time required to compute it. We have implemented our algorithm and tested its performance on complex benchmarks consisting of up to 50,000 joints. We demonstrate that in some cases our algorithm is able to achieve up to two orders of magnitude of performance improvement, while providing a high precision, error-bounded approximation of the quasi-statics of the simulated linkage.
The Polymatroid Steiner Problems

The Steiner tree problem asks for a minimum cost tree spanning a given set of terminals S⊂eqV in a weighted graph G = (V,E,c), c:E→ R+. In this paper we consider a generalization of the Steiner tree problem, so called Polymatroid Steiner Problem, in which a polymatroid P = P(V) is defined on V and the Steiner tree is required to span at least one base of P (in particular, there may be a single base S⊂eqV). This formulation is motivated by the following application in sensor networks – given a set of sensors S = {s1,…,s k }, each sensor s i can choose to monitor only a single target from a subset of targets X i , find minimum cost tree spanning a set of sensors capable of monitoring the set of all targets X = X1 ∪ … ∪ X k . The Polymatroid Steiner Problem generalizes many known Steiner tree problem formulations including the group and covering Steiner tree problems. We show that this problem can be solved with the polylogarithmic approximation ratio by a generalization of the combinatorial algorithm of Chekuri et al. (2002). We also define the Polymatroid directed Steiner problem which asks for a minimum cost arborescence connecting a given root to a base of a polymatroid P defined on the terminal set S. We show that this problem can be approximately solved by algorithms generalizing methods of Chekuri et al. (2002).
Amorphous Mixed TiO2 and SiO2 Films on Si(100) by Chemical Vapor Deposition

Amorphous thin films of composition TixSi1-xO2 have been grown by low pressure chemical vapor deposition on silicon (100) substrates using Si(O-Et)4 and either Ti(O-iPr)4 or anhydrous Ti(NO3)4 as the sources of SiO2 and TiO2, respectively. The substrate temperature was varied between 300 and 535°C, and the precursor flow rates ranged from 5 to 100 sccm. Under these conditions growth rates ranging from 0.6 to 90.0 nm/min were observed. As-deposited films were amorphous to X-rays and SEM micrographs showed smooth, featureless film surfaces. Cross-sectional TEM showed no compositional inhomogeneity. RBS revealed that x (from the formula TixSi1-xO2) was dependent upon the choice of TiO2 precursor. For films grown using TTIP-TEOS x could be varied by systematic variation of the deposition conditions. For the case of TN-TEOS x remained close to 0.5 under all conditions studied. One explanation is the existence of a specific chemical reaction between TN and TEOS prior to film deposition. TEOS was mixed with a CCl4 solution of TN at room temperature to produce an amorphous white powder (Ti/Si = 1.09) and 1HNMR of the CCl4 solution indicated resonances attributable to ethyl nitrate.
Increased risk of second cancer among patients with ovarian borderline tumors

Objectives. Several studies have demonstrated a higher risk of colorectal and breast cancers subsequent to invasive ovarian cancer. Such risk has not been investigated for ovarian borderline tumors. We aim to evaluate the risk of subsequent cancer occurrence among patients with borderline ovarian tumors in a population-based setting. Methods. We identified 171 patients with a diagnosis of borderline ovarian tumors recorded at the Geneva Cancer Registry, Switzerland. We calculated age and period standardized incidence ratios (SIR) of second tumor occurrence by dividing the number of observed cases by the number of expected cases in the cohort, using cancer incidence rates of the general female population. Results. The risk of developing second cancer was 1.85-fold (95% Confidence Interval [CI]: 1.10–2.92, n=16) higher among women with borderline ovarian tumors compared to that expected in the general population. The excess of risk primarily concerned colorectal cancer (SIR: 3.97, CI: 1.38–12.95, n=5) and breast cancer (SIR: 2.09, CI: 0.84–4.31, n=7), but the latter result was not statistically significant ( p=0.09). The increased risk of developing second cancer was mainly observed among patients diagnosed with ovarian borderline tumors occurring before the age of 50. These results were not explained by surveillance bias or by metastasis from one site to another. Conclusion. Women with ovarian borderline tumors have an increased risk of developing secondary cancer, particularly colorectal cancer. These results point to potential common risk factors for these tumors and ask for close surveillance of patients with borderline ovarian tumors.
Volume Change Accompanying Rubber Extension

Abstract : A new expression for the volume dilation accompanying rubber extension is used to describe published data. This new equation is shown to describe the data better than either that derived from simple kinetic theory or that derived from the Mooney-Rivlin Equation. (Author)
Optical scattering angles and Bose-stimulated motion in cold atomic gas

Bose statistics imply a substantial enhancement at small angles for light scattering off a cold, Bose gas. The enhancement increases dramatically at the Bose-Einstein temperature. This phenomenon could be utilized to eliminate almost entirely the heating of the gas by a weak probe light beam.
Plasmonic nanogap-enhanced Raman scattering using a resonant nanodome array.

The optical properties and surface-enhanced Raman scattering (SERS) of plasmonic nanodome array (PNA) substrates in air and aqueous solution are investigated. PNA substrates are inexpensively and uniformly fabricated with a hot spot density of 6.25 × 106 mm−2 using a large-area nanoreplica moulding technique on a flexible plastic substrate. Both experimental measurement and numerical simulation results show that PNAs exhibit a radiative localized surface plasmon resonance (LSPR) due to dipolar coupling between neighboring nanodomes and a non-radiative surface plasmon resonance (SPR) resulting from the periodic array structure. The high spatial localization of electromagnetic field within the ∼10 nm nanogap together with the spectral alignment between the LSPR and excited and scattered light results in a reliable and reproducible spatially averaged SERS enhancement factor (EF) of 8.51 × 107 for Au-coated PNAs. The SERS enhancement is sufficient for a wide variety of biological and chemical sensing applications, including detection of common metabolites at physiologically relevant concentrations.
Language-Oriented Careers in the Federal Government*

SEVERAL ARTICLES have appeared recently which aim at answering the student's complaint: "What can I do with a Bachelor of Arts degree in language besides teach?"' A recent Modem Language Association publication, English: The Pre-Professional Major (1973) by Linwood Orange, though aimed at English majors, contains valuable suggestions for any liberal arts major. In an effort to reorient the thinking of the liberal arts major towards his career potential, Professor Orange documents the fact that an English major, with his general liberal arts background, can enter careers in four major professional fields: law, medicine, business, and federal service. Above all other qualifications for a career in these.areas, the respondents to Professor Orange's survey of professional organizations stressed a candidate's ability "to become knowledgeable in previously unfamiliar areas."2
Plasma Shape Control on the National Spherical Torus Experiment (NSTX) using Real-time Equilibrium Reconstruction

Plasma shape control using real-time equilibrium reconstruction has been implemented on the National Spherical Torus Experiment (NSTX). The rtEFIT code originally developed for use on DIII-D was adapted for use on NSTX. The real-time equilibria provide calculations of the flux at points on the plasma boundary, which are used as input to a shape control algorithm known as isoflux control. The flux at the desired boundary location is compared with a reference flux value, and this flux error is used as the basic feedback quantity for the poloidal field coils on NSTX. The hardware that comprises the control system is described, as well as the software infrastructure. Examples of precise boundary control are also presented.
Circuitry, Architecture, and Functional Dynamics of Visual Cortex

A fundamental understanding of the mechanisms of cortical processing requires an examination of the relationships of cortical circuitry, functional architecture, and receptive field properties. Ultimately, this kind of analysis can be utilized to explore the neurobiological basis of psychophysics and perception. At the onset our studies were intended to account for the then known receptive field properties of cortical cells in terms of their underlying circuitry, but surprisingly a good part of the cortical circuit appeared to be in violation of the principles of cortical architecture, and this led us to explore the possibility of new, more complex properties of cortical cells. It has become increasingly possible to relate the responsive specificity of cortical cells, and the circuitry underlying this specificity, to the perceptual capabilities of the visual system by performing analogous experiments on single cells and in human psychophysics.
Economics of nuclear power: Past record, present trends and future prospects☆

Abstract We examine the economic record of operating U.S. reactors, factors affecting the economics of nuclear plants under construction and opportunites for nuclear energy to escape from the predicament it faces today. The records of the 80 operating reactors indicate that they represent an indispensable asset, generating power at a lower cost than fossil-fueled alternatives. Yet many reactors under construction have suffered so much delay and cost escalation that they have become a financial burden to utilities and their customers. The technical, economic, and institutional reasons for this grotesque contrast between nuclear energy's potential and the problems it faces today are discussed. Changes necessary to improve the economics of nuclear power are also discussed. It is argued that the deployment of a meltproof reactor design, several of which are now under development, may solve the multifaceted problems of over-regulation, long schedules, and financial risks.
Spread-spectrum multi-h modulation

Applying a direct random spreading sequence to a digital information sequence prior to multi-h modulation creates a new class of signals called spread-spectrum multi-h (SSMH) signaling. By spreading a known bandwidth efficient modulation scheme, the power spectral density is controlled so that the transmitted spectrum will have a wide, flat mainlobe and rapid sidelobe rolloff. Coincidentally, the power efficient modulation allows transmission at lower signal-to-noise ratios when the receiver knows a priori the spreading sequence and modulation index sequence. Optimal receiver structures are derived and numerically evaluated in an additive white Gaussian noise environment. It is shown that performance is dependent on the spreading sequence, the modulation indexes, and the possible phase states and can exceed direct sequence binary phase-shift keying by 1-2 dB at bit error rates of 10/sup -5/. Composite likelihood ratio analysis reveals a reduction of 50-70% in detectability of completely known SSMH signals vis-a-vis direct-sequence binary phase shift keying (DS/BPSK) at error rates of 10/sup -4/. >
Grassroots: a system providing a uniform framework for communicating, structuring, sharing information, and organizing people

People keep pieces of information in diverse collections such as folders, hotlists, e-mail inboxes, newsgroups, and mailing lists. These collections mediate various types of collaborations including communicating, structuring, sharing information, and organizing people. Grassroots is a system that provides a uniform framework to support people''s collaborative activities mediated by collections of information. The system seamlessly integrates functionalities currently found in such disparate systems as e-mail, newsgroups, shared hotlists, hierarchical indexes, hypermail, etc. Grassroots co-exists with these systems in that its users benefit from the uniform image provided by Grassroots, but other people can continue using other mechanisms, and Grassroots leverages from them. The current Grassroots prototype is based on an http-proxy implementation, and can be used with any Web browser. In the context of the design of a next-generation version of the Web, Grassroots demonstrates the utility of a uniform notification infrastructure.
Explaining the Entropy Excess in Clusters and Groups of Galaxies without Additional Heating

The X-ray luminosity and temperature of clusters and groups of galaxies do not scale in a self-similar manner. This has often been interpreted as a sign that the intracluster medium has been substantially heated by non-gravitational sources. In this paper, we propose a simple model which, instead, uses the properties of galaxy formation to explain the observations. Drawing on available observations, we show that there is evidence that the efficiency of galaxy formationwas higher in groups than in clusters. If confirmed, this would deplete the low-entropy gas in groups, increase their central entropy and decrease their X-ray luminosity. A simple, empirical, hydrostatic model appears to match both the luminositytemperature relation of clusters and properties of their internal structure as well. Subject headings: cosmology: theory, intergalactic medium
Oxidative conversion of δ-sultones to γ-lactones.

δ-Sultones, prepared by C–H insertion, can be oxidatively converted to γ-lactones by treatment with t-BuOK/t-BuOOH. An intermediate in the synthesis of (−)-eburnamonin was prepared using this approach.
Opinion dynamics: Rise and fall of political parties

We analyze the evolution of political organizations using a model in which agents change their opinions via two competing mechanisms. Two agents may interact and reach consensus, and additionally, individual agents may spontaneously change their opinions by a random, diffusive process. We find three distinct possibilities. For strong diffusion, the distribution of opinions is uniform and no political organizations (parties) are formed. For weak diffusion, parties do form and furthermore, the political landscape continually evolves as small parties merge into larger ones. Without diffusion, a pattern develops: parties have the same size and they possess equal niches. These phenomena are analyzed using pattern formation and scaling techniques.
Pseudocompact algebras, profinite groups and class formations

A pseudocompact ring A is a complete Hausdorff topological ring which admits a system of open neighborhoods of 0 consisting of two sided ideals I for which A/I is an Artin ring. A complete HausdorR topological A-module M is said to be pseudocompact if it has a system of open neighborhoods of 0 consisting of submodules N for which M/N has finite length. The category G?,, of pseudocompact (I-modules is an Abelian category with exact inverse limits and enough projectives. Such generalities, which are more or less well known, are gathered in the first section for the convenience of the reader. To get more interesting results, we must introduce some commutativity by assuming that, in addition, (1 is a pseudocompact algebra over a commutative pseudocompact ring Q (see definition in Section 2). We may then define a tensor product on %A and introduce its derived functor 554. The category %+,, of discrete cl-modules, which is dual to VA0 by Proposition 2.3, also plays an important role through the bifunctor Horn : V, x 5BA + go and its derived functor &zt. We then have the proper setting for doing homological algebra. This is done in Section 3 which generalizes the elementary results on homological dimension in complete Noetherian semilocal rings. As an immediate application we find that if s2({xi}} is the algebra of noncommutative formal power series in {xi} over Q, then gl dim J2{{xi}} = gl dim Sa + 1 (Theorem 3.9). We recall that a profinite group is a compact totally disconnected topological group, i.e., an inverse limit of finite groups. We define the complete group
Applying Specialization to Process Models

Object-oriented analysis and design methodologies take full advantage of the object approach when it comes to modeling the objects in a system. However, system behavior continues to be modeled using essentially the same tools as in traditional systems analysis: state diagrams and dataflow diagrams. In this paper we extend the notion of specialization to these process representations and identify a set of transformations which, when applied to a process description, always result in specialization. We analyze specific examples in detail and demonstrate that such a use of specialization is not only theoretically possible, but shows promise as a method for categorizing and analyzing processes. We identify a number of apparent inconsistencies between process specialization and the object specialization which is part of the object-oriented approach. We demonstrate that these apparent inconsistencies are superficial and that the approach we take is compatible with the traditional notion of specialization.
Disruption versus Tiebout improvement: the costs and benefits of switching schools

Most students change schools at some point in their academic careers, but some change very frequently and some schools experience a great deal of turnover. While many argue that mobility harms students, economists tend to emphasize Tiebout type moves to procure better school quality (SQ). This paper disentangles the disruption effects of moves from changes in SQ. Importantly, it identifies the negative externality movers impose on other students. Student turnover is shown to entail a substantial cost for movers and non-movers alike. This cost appears to be larger for lower income and minority students who typically attend much higher turnover schools.
Failure site transition in Pb-free solder joints caused by manufacturing variabilities in BGA and MLF components in low cycle fatigue analysis

A comprehensive three level design of experiment that is applied on the manufacturing process to compare the effect of variability in printing and reflow processes on quality and durability of Micro Lead Frame (MLF) and Ball Grid Array (BGA) components. The quality and durability of the BGA and MLF components were studied very closely by thermo-mechanical experiment and finite element simulation. Different populations of failures indicating different failure site and mechanisms were observed in both BGA and MLF components. Conflictions were observed when parameter variations caused durability improvement in one type and durability degradation in the other package.
The Impact of Costliness, Competitive Importance, and Modularity of Investments on Outsourcing

This study is motivated by examples of outsourcing that are not readily explained by widely established economic theories. We extend recent literature that develops the idea that outsourcing can help firms avoid overinvestment by specifying more precisely the conditions under which this thesis is likely to apply. Our extension is realized through a two-period game theoretic model in which the outsourcing and in-house investments are driven by (1) the cost required to develop a product or process module, (2) competitive relevance, defined as the module's share in the production cost or the module's importance to the customer, and (3) modularity, defined as the extent to which generic investments in the module can approach firm-specific investments in terms of the overall product/process performance. The analysis generates predictions about what types of insourcing, outsourcing, and non-sourcing behaviors are likely to emerge in different parts of the parameter space. Outsourcing to a more concentrated industry upstream emerges at equilibrium when modularity is high, relevance low to medium, and development cost high enough that none or only a subset of focal firms wants to invest. While firms are forced to insource and overinvest due to a prisoner's dilemma when the development cost is sufficiently high relative to the module's relevance, we do not find outsourcing equilibria that solve this problem in a two-period game with no commitment. This result implies that some form of tacit coordination in a multi-period game may be necessary. We conclude the study with a discussion of empirical implications.
Combining experimental and mathematical modeling to reveal mechanisms of macrophage-dependent left ventricular remodeling

Background: Progressive remodeling of the left ventricle (LV) following myocardial infarction (MI) can lead to congestive heart failure, but the underlying initiation factors remain poorly defined. The objective of this study, accordingly, was to determine the key factors and elucidate the regulatory mechanisms of LV remodeling using integrated computational and experimental approaches. Results: By examining the extracellular matrix (ECM) gene expression and plasma analyte levels in C57/BL6J mice LV post-MI and ECM gene responses to transforming growth factor (TGF-b1) in cultured cardiac fibroblasts, we found that key factors in LV remodeling included macrophages, fibroblasts, transforming growth factor-b1, matrix metalloproteinase-9 (MMP-9), and specific collagen subtypes. We established a mathematical model to study LV remodeling post-MI by quantifying the dynamic balance between ECM construction and destruction. The mathematical model incorporated the key factors and demonstrated that TGF-b1 stimuli and MMP-9 interventions with different strengths and intervention times lead to different LV remodeling outcomes. The predictions of the mathematical model fell within the range of experimental measurements for these interventions, providing validation for the model. Conclusions: In conclusion, our results demonstrated that the balance between ECM synthesis and degradation, controlled by interactions of specific key factors, determines the LV remodeling outcomes. Our mathematical model, based on the balance between ECM construction and destruction, provides a useful tool for studying the regulatory mechanisms and for predicting LV remodeling outcomes.
Risk Management in Agricultural Production

The early 1970s marked the beginning of a new era in U.S. agriculture. The stagnant markets and persistent excess production of the previous two decades gave way to a more finely balanced supply and demand for agricultural commodities. Prices for most farm commodities increased nominally and became much more variable. During this same period several important changes occurred in agriculture's financial structure. Land values and rents were rapidly bid upward. Expansion in land, facilities, and equipment occurred at a rapid pace-the result in part of expectations of sustained income growth and a monetary policy that favored expansion. Changes in financial markets made the cost of the debt accompanying this expansion somewhat more sensitive to short-run changes in interest rates. Certain classes of farmers, particularly new entrants and those pursuing a rapid expansion strategy, became extremely vulnerable to changes in prices, costs, and production. Risk exposure increased and the economic resilience of many farm businesses declined as a result of this ten-year period. This rapid change generated concern on the parts of farmers, researchers, and the general public on the adequacy of farmers' managerial skills to cope with this uncertain environment. This concern was grounded in traditional concern for the welfare of farm families. However food security as well as the efficiency and structure of the agricultural sector were also considered to be at stake. This paper considers managerial response to risk from an operational perspective. I will describe briefly the farm management process and consider how the assessment and control of risk might be incorporated. My primary motive, however, is to use this framework as a means to identify economic research and extension problems that must be addressed if the managerial skills of agricultural decision makers are to be improved.
Pd-Catalyzed N-Arylation of Secondary Acyclic Amides: Catalyst Development, Scope, and Computational Study

We report the efficient N-arylation of acyclic secondary amides and related nucleophiles with aryl nonaflates, triflates, and chlorides. This method allows for easy variation of the aromatic component in tertiary aryl amides. A new biaryl phosphine with P-bound 3,5-(bis)trifluoromethylphenyl groups was found to be uniquely effective for this amidation. The critical aspects of the ligand were explored through synthetic, mechanistic, and computational studies. Systematic variation of the ligand revealed the importance of (1) a methoxy group on the aromatic carbon of the “top ring” ortho to the phosphorus and (2) two highly electron-withdrawing P-bound 3,5-(bis)trifluoromethylphenyl groups. Computational studies suggest the electron-deficient nature of the ligand is important in facilitating amide binding to the LPd(II)(Ph)(X) intermediate.
A Thermal Spike Analysis of Low Energy Ion Activated Surface Processes

A thermal spike analysis was utilized to predict the time evolution of energy propagation through a solid resulting from energetic particle impact. An analytical solution was developed that can predict the number of surface excitations such as desorption, diffusion or chemical reaction activated by an energetic particle. The analytical solution is limited to substrates at zero Kelvin and to materials with constant thermal diffusivities. These limitations were removed by developing a computer numerical integration of the propagation of the thermal spike through the solid and the subsequent activation of surface processes.
Existence of Magnetic Compressible Fluid Stars

The existence of magnetic star solutions which are axi-symmetric stationary solutions for the Euler–Poisson system of compressible fluids coupled to a magnetic field is proved in this paper by a variational method. Our method of proof consists in deriving an elliptic equation for the magnetic potential in cylindrical coordinates in \({\mathbb{R}^3}\), and obtaining the estimates of the Green’s function for this elliptic equation by transforming it to 5-Laplacian.
Social science computing: 1967-1972

Social science computing continues to grow both in quantity and variety of problem applications. Increasing numbers of social scientists are using increasing amounts of computer time on an increasing array of machines. Social scientists have upgraded their competence in computing and produced a number of programming systems for use in their research and instructional activities. Each year more social science graduate students are trained in the use of computers, and more social science departments now have at least one faculty member who is competent in computing. Of course, all these developments did not occur in the past five years. Important preliminary steps were taken as early as fifteen years ago. But during the period 1967--1972, social science computing has made significant progress and is now recognized as a member of the computing community.
On conformal biharmonic immersions

This paper studies conformal biharmonic immersions. We first study the transformations of Jacobi operator and the bitension field under conformal change of metrics. We then obtain an invariant equation for a conformal biharmonic immersion of a surface into Euclidean 3-space. As applications, we construct a two-parameter family of non-minimal conformal biharmonic immersions of cylinder into \({\mathbb{R}^3}\) and some examples of conformal biharmonic immersions of four-dimensional Euclidean space into sphere and hyperbolic space, thus providing many simple examples of proper biharmonic maps with rich geometric meanings. These suggest that there are abundant proper biharmonic maps in the family of conformal immersions. We also explore the relationship between biharmonicity and holomorphicity of conformal immersions of surfaces.
IS THE OPTICALLY UNIDENTIFIED RADIO SOURCE FIRST J121839.7+295325 A DARK LENS?

We present evidence that the optically unidentified radio source FIRST J121839.7+295325 may be strongly lensing a background galaxy. We estimate the redshift of the assumed gravitational arc, discovered in parallel imaging with HST, from MMT-Blue Channel spectroscopy to be zarc = 2.48−0.05+0.14. We present lens models with an Einstein radius of RE = 1.3'' which contains a mass of Mdyn = 1012 ± 0.5 M☉, where the uncertainty reflects the range of possible lens redshifts. The putative lens is not detected to Jlim = 22.0 mag and Hlim = 20.7 mag in our MMT-SWIRC imaging. Using the flux limits from WFPC2 and SWIRC, we estimate that the dynamical mass-to-light ratio of J121839.7+295325 is Mdyn/LB 10 M☉ L☉−1 for AV = 1 mag, and this lower limit could be as high as 30 M☉ L☉−1 for AV = 0 mag. Since the radio source is optically unidentified (Vlim = 25.5 mag) and has a radio flux of S1.4 GHz = 33 mJy, it is likely a massive early-type galaxy which hosts a radio-loud AGN at 0.8 zradio 1.5. However, the present data cannot uniquely determine the mass-to-light ratio of the lensing galaxy, and hence the possibility that this system may be a reasonably dark lens is not ruled out.
The Total Synthesis of Roquefortine C and a Rationale for the Thermodynamic Stability of Isoroquefortine C over Roquefortine C

The first total synthesis of roquefortine C is achieved by implementation of a novel elimination strategy to construct the thermodynamically unstable E-dehydrohistidine moiety. Molecular modeling studies are presented which explain the instability of the roquefortine C structure compared to that of isoroquefortine C.
SEDIMENTATION OF GLASS BEADS UNDER THE INFLUENCE OF GRAVITY

The quasi-two-dimensional sedimentation of 0.06 cm diameter silica spheres in viscous oil (between glass plates separated by a 1 mm gap) results in quasi-one dimensional rough surfaces. These surfaces are rough on all length-scales between the particle size and the cell size, but different roughness exponents are observed in each of two well defined regimes (αs=0.81±0.03 for L≤2 cm and αl=0.92±0.05 for L≥2 cm). The dynamical exponent, β, is measured to be 0.48±0.16. The role and range of hydrodynamic forces must be considered before this system can be related to available rough interface theories. A first attempt at assessing the effect of hydrodynamics yields a noise spectrum whose probability distribution is close to Gaussian (with significant excess of large fluctuations) and whose correlation function resembles that measured for density-density correlations in the oil far above the growing interface.
Tidally forced viscous heating in a partially molten Io

Models of Io that generate most of their heat by viscous dissipation in a partially molten (perhaps nearly liquid) asthenosphere are developed: a partially molten asthenosphere model and a partially molten interior model. An approximate thermal analysis is carried out, suggesting the possibility of a stable steady state. The models are consistent with observations of widely dispersed hot spots on the Io surface that radiate most of Io's heat loss. The hot spots imply that magmas carry most of the dissipative heating that is naturally accounted for in the models.
Integrated Reservoir Description and Flow Performance Evaluation : Glenn Pool Field-Self Unit Study

Abstract This paper presents the study of an integrated approach to reservoir description as a part of the DOE-Class I Projects to improve the oil recovery from a mature oil field. The field selected is the Self Unit of the Glenn Pool Field that covers 160 acres. An integrated reservoir description was constructed which honors the geological, geophysical, and engineering data using geostatistical (stochastic) as well as the deterministic models. The description was validated by comparing the simulated results with static (well log and well core) as well as dynamic (well test) information. Both stochastic and deterministic models replicate the geological model very well. The deterministic model predicts an optimistic performance, whereas the stochastic model follows the field data much better. The incorporation of geophysical information, taken from tomography surveys, improves the reservoir description when comparing with the observed well test information. Using the description from each of the models, the flow simulations were conducted to match the historical performance and to predict the future production. Based on the flow simulation and the economic analysis, the plan of recompleting the wells along with an increase in the injection rate is found to be the most feasible solution to improve the performance of the Self Unit. The preliminary results from the implementation of this plan indicate expected results.
The Angular Momentum Content and Evolution of Class I and Flat-Spectrum Protostars

We report on the angular momentum content of heavily embedded protostars on the basis of our analysis of the projected rotation velocities (v sin i) of 38 Class I/flat-spectrum young stellar objects recently presented by Doppmann and others. After correcting for projection effects, we find that infrared-selected Class I/flat-spectrum objects rotate significantly more quickly (median equatorial rotation velocity ~38 km s-1) than classical T Tauri stars (CTTSs; median equatorial rotation velocity ~18 km s-1) in the ? Ophiuchi and Taurus-Aurigae regions. Projected rotation velocity (v sin i) is weakly correlated with Teff in our sample but does not seem to correlate with Br? emission (a common accretion tracer), the amount of excess continuum veiling (rk), or the slope of the spectral energy distribution between the near- and mid-IR (?). The detected difference in rotation speeds between Class I/flat-spectrum sources and CTTSs proves difficult to explain without some mechanism that transfers angular momentum out of the protostar between the two phases. Assuming that Class I/flat-spectrum sources possess physical characteristics (M*, R*, and B*) typical of pre?main-sequence stars, fully disk-locked Class I objects should have corotation radii within their protostellar disks that match well (within 30%) with predicted magnetic coupling radii. The factor of 2 difference in rotation rates between Class I/flat-spectrum and CTTS sources when interpreted in the context of disk-locking models also implies a factor of 5 or greater difference in mass accretion rate between the two phases. A lower limit of ~ 10-8 M? yr-1 for objects transitioning from the Class I/flat-spectrum stage to CTTSs is required to account for the difference in rotation rates of the two classes by angular momentum extraction through a viscous disk via magnetic coupling.
Toward developing an instrument for measuring milking management practices

Abstract Based on literature review and on interviews with 9 dairy management experts, an instrument composed of a checklist of indicators to measure milking management effectiveness was developed. Reliability of the instrument was tested by comparing experts' scores and rankings of milking management practices with scores and rankings given by a non-expert using the instrument. Based on total scores, no difference was found between the non-expert's andthe experts' rankings of 31 large California Dairies (Spearman's rank correlation (rs=0.55, P
Gradient space under orthography and perspective

Abstract Mackworth's gradient space has proved to be a useful tool for image understanding. However, descriptions of its important properties have been somewhat scattered in the literature. The fundamental properties of the gradient space under orthography and perspective, and for curved surfaces, are developed and summarized. While largely a recounting of previously published results, there are a number of new observations, particularly concerning the gradient space and perspective projection. In addition, the definition and use of vector gradients as well as surface gradients provides concise notation for several results. The properties explored include the orthographic and perspective projections themselves; the definition of gradients; the gradient space consequences of vectors (edges) belonging to one or more surfaces, and of several vectors being contained on a single surface; and the relationships between vanishing points, vanishing lines, and the gradient space. The paper is intended as a study guide for learning about the gradient space, as well as a reference for researchers working with gradient space.
IRREVERSIBLE CHARACTER OF THE LATE CHANGES AFTER HEPATECTOMY

The symptoms of advanced liver insufficiency, in the hepatectomized rabbit, are irreversible. That is to say, cross-transfusions between liverless rabbits and normal ones fail to ameliorate the symptoms of liver deprivation once they are established. The normal rabbits show no symptoms suggesting that toxic substances have accumulated in the blood of the hepatectomized ones.