cssi/SciSciGPT-SciSciNet huggingface dataset:
A method for relating type of crash to traffic flow characteristics on urban freeways

A method is developed to determine how crash characteristics are related to traffic flow conditions at the time of occurrence. Crashes are described in terms of the type and location of the collision, the number of vehicles involved, movements of these vehicles prior to collision, and severity. Traffic flow is characterized by central tendencies and variations of traffic flow and flow/occupancy for three different lanes at the time and place of the crash. The method involves nonlinear canonical correlation applied together with cluster analyses to identify traffic flow regimes with distinctly different crash taxonomies. A case study using data for more than 1000 crashes in Southern California identified twenty-one traffic flow regimes for three different ambient conditions: dry roads during daylight (eight regimes), dry roads at night (six regimes), and wet conditions (seven regimes). Each of these regimes has a unique profile in terms of the type of crashes that are most likely to occur, and a matching of traffic flow parameters and crash characteristics reveals ways in which congestion affects highway safety.
Sildenafil (VIAGRATM), a potent and selective inhibitor of type 5 cGMP phosphodiesterase with utility for the treatment of male erectile dysfunction

Abstract 5-(2′-Alkoxyphenyl)pyrazolo[4,3-d]pyrimidin-7-ones, and in particular our preferred compound, sildenafil (VIAGRATM), discovered through a rational drug design programme, are potent and selective inhibitors of the type 5 cGMP phosphodiesterase from both rabbit platelets and human corpus cavernosum. Sildenafil is currently in the clinic for the oral treatment of male erectile dysfunction.
Generating New Molecular Function: A Lesson from Nature

Trying to model nature: Nature has evolved new molecular function by creating diverse collections of chemical structures and selecting for molecules with desired biological properties. An example of this is the recombination of germ-line genes for the formation of antibodies with refined specificities (see scheme). Chemists, biologists, and physicists are now employing this combinatorial approach with great success to generate molecules with properties never before observed in nature or in the laboratory.
Untangling the merger history of massive black holes with LISA

ABSTRA C T Binary black hole coalescences emit gravitational waves that will be measurable by the space-based detector LISA to large redshifts. This suggests that LISA may be able to observe black holes grow and evolve as the Universe evolves, mapping the distribution of black hole masses as a function of redshift. An immediate difficulty with this idea is that LISA measures certain redshifted combinations of masses with good accuracy: if a system has some mass parameter m, then LISA measuresO1a zUm. This mass‐ redshift degeneracy makes it difficult to follow the mass evolution. In many cases, LISA will also measure the luminosity distance D of a coalescence accurately. Since cosmological parameters (particularly the mean density, the cosmological constant and the Hubble constant) are now known with moderate precision, we can obtain z from D and break the degeneracy. This makes it possible to untangle the mass and redshift and to study the mass and merger history of black holes. Mapping the black hole mass distribution could open a window on to an early epoch of structure formation.
Sticking with Carrots and Sticks (Sticking Points Aside): A Response to Ventakapuram, Goldberg, and Forrow

I would like to thank Sridhar Ventakapuram, Daniel Goldberg, and Lachlan Forrow for thoughtful responses to my article (1–4). All endorse my main point, that conditioning the very aid that patients need in order to become healthier on their success in becoming healthier is (usually) wrong. They may think me, however, too friendly to an approach that gives patients “carrots” or “sticks” depending on how healthy their choices are. Ventakapuram writes, “What comes out of the article most clearly is that Eyal is fine with the carrots and sticks approach to health policy, he just wants to help clarify what should and should not be the carrots and sticks”.
The Diffuse Supernova Neutrino Background

The diffuse supernova neutrino background (DSNB) is the weak glow of megaelectronvolt neutrinos and antineutrinos from distant core-collapse supernovae. The DSNB has not been detected yet, but the Super-Kamiokande (SK) 2003 upper limit on the flux is close to predictions, now quite precise, that are based on astrophysical data. If SK is modified with dissolved gadolinium to reduce detector backgrounds and increase the energy range for analysis, then it should detect the DSNB at a rate of a few events per year, providing a new probe of supernova neutrino emission and the cosmic core-collapse rate. If the DSNB is not detected, then new physics will be required. Neutrino astronomy, although uniquely powerful, has proven extremely difficult—only the Sun and the nearby Supernova 1987A have been detected to date—so the promise of detecting new sources soon is exciting indeed.
Total synthesis of the cytotoxic alkaloid 22-hydroxyacuminatine

The total synthesis of the cytotoxic alkaloid 22-hydroxyacuminatine has been achieved in 14.9% overall yield starting from 2-methylcinnamic acid via the key intermediate 5-ethoxymethylisoquinolin-1-one.
Hypofractionated SBRT versus conventionally fractionated EBRT for prostate cancer: comparison of PSA slope and nadir.

Patients with early stage prostate cancer have a variety of curative radiotherapy options, including conventionally-fractionated external beam radiotherapy (CF-EBRT) and hypofractionated stereotactic body radiotherapy (SBRT). Although results of CF-EBRT are well known, the use of SBRT for prostate cancer is a more recent development, and long-term follow-up is not yet available. However, rapid post-treatment PSA decline and low PSA nadir have been linked to improved clinical outcomes. The purpose of this study was to compare the PSA kinetics between CF-EBRT and SBRT in newly diagnosed localized prostate cancer. 75 patients with low to low-intermediate risk prostate cancer (T1-T2; GS 3 + 3, PSA 70.2 Gy, <76 Gy) to the prostate only, were identified from a prospectively collected cohort of patients treated at the University of California, San Francisco (1997–2012). Patients were excluded if they failed therapy by the Phoenix definition or had less than 1 year of follow-up or <3 PSAs. 43 patients who were treated with SBRT to the prostate to 38 Gy in 4 daily fractions also met the same criteria. PSA nadir and rate of change in PSA over time (slope) were calculated from the completion of RT to 1, 2 and 3 years post-RT. The median PSA nadir and slope for CF-EBRT was 1.00, 0.72 and 0.60 ng/ml and -0.09, -0.04, -0.02 ng/ml/month, respectively, for durations of 1, 2 and 3 years post RT. Similarly, for SBRT, the median PSA nadirs and slopes were 0.70, 0.40, 0.24 ng and -0.09, -0.06, -0.05 ng/ml/month, respectively. The PSA slope for SBRT was greater than CF-EBRT (p < 0.05) at 2 and 3 years following RT, although similar during the first year. Similarly, PSA nadir was significantly lower for SBRT when compared to EBRT for years 2 and 3 (p < 0.005). Patients treated with SBRT experienced a lower PSA nadir and greater rate of decline in PSA 2 and 3 years following completion of RT than with CF-EBRT, consistent with delivery of a higher bioequivalent dose. Although follow-up for SBRT is limited, the improved PSA kinetics over CF-EBRT are promising for improved biochemical control.
Resolution Characteristics of Holographic Particle Image Velocimetry

The resolution characteristics of in-line holographic imaging systems for application to velocity field measure- ment in turbulent and other vortical flows has been investigated experimentally. It is shown that the diameter of seed particles strongly influences the maximum size of the test volume that can be used as well as the spatial resolution of the measurement. Velocity measurements in a vortex ring flow using a two-axis holographic recording system are reported. The spatial resolution of this system is approximately 1 mm. OLOGRAPHIC imaging of flows seeded with small particles can be a useful technique for velocity field mea- surement in turbulent and other vortical flows. Several investi- gators have reported velocity measurements using holographic techniques.1'2 Two basic approaches have been proposed. In most cases in-line doubly exposed holograms of the seeded flow are obtained. The velocity is determined from the dis- placement of the particles on the reconstructed images. This approach is what we call holographic particle image velocime- try (HPIV) because it is a natural extension of planar particle image velocimetry.3 A second approach4'5 is to obtain a tempo- ral sequence of holograms. The velocity is determined by tracking individual particles as a function of time. The main advantage of HPIV compared to particle tracking techniques is that the particle displacement is determined by local analysis of the reconstructed images which results in reduced image processing requirements. Turbulent flow measurement requires a large spatial dy- namic range. This requirement becomes more severe as the Reynolds number is increased. A large spatial dynamic range requires imaging of very small particles in a large test volume. Research on in-line holographic imaging systems for particle size measurement has shown a limit to the test volume depth of 50-80 far-field distances.6'7 (The far-field distance is defined here as d2/\ where d is the diameter of the particle and X the wavelength of the laser used to record the hologram.) The depth of field of the reconstructed particle images is of the order of one far-field distance.8 The depth of field of the particle image is a good measure of the spatial resolution of the velocity measurement. It follows that the resolution character- istics of the holographic imaging system can severely limit the spatial dynamic range of HPIV. In this paper we examine experimentally the resolution char- acteristics of in-line holographic imaging systems. A two-axis holographic recording system designed for high resolution ve- locity field measurements is described. Finally, velocity mea- surements in a vortex ring flow using this HPIV system are reported. The dynamic range requirements of typical HPIV recording systems dictate that the hologram be positioned at a large distance from the particles. In this case the light intensity distribution on the hologram plane is given by Fraunhofer theory9 _ , Trt/2 . 1=1- —— sin 2\z . Air2\ |~ /T£/A/Tcfr) —— sin —— } \2Ji\ —— / —— 2\z \Xz/ |_ \\z/l XzJ '<Kdr
Butyrate and deoxycholic acid play common and distinct roles in HCT116 human colon cell proliferation.

Abstract Consumption of a high-fat diet causes an increase in bile acid deoxycholic acid (DCA) in colon lumen and colon cancer risk, while butyrate, an intestinal microbiota metabolite of dietary fiber, has been shown to exhibit colon cancer-preventive effects. To distinguish these opposing effects of DCA and butyrate (two major metabolites in colon lumen), we examined the effects of physiologically relevant doses of butyrate (0.5–2 mmol/l) and DCA (0.05–0.3 mmol/l) on colon cell proliferation. We hypothesize that butyrate and DCA each modulates the cell cycle and apoptosis via common and distinct cellular signaling targets. In this study, we demonstrated that both butyrate and DCA inhibited cell proliferation by up to 89% and 92% and increased cell apoptosis rate by up to 3.1- and 4.5-fold, respectively. Cell cycle analyses revealed that butyrate led to an increase in G1 and G2 fractions with a concomitant drop in the S-phase fraction, but DCA induced an increase in only G1 fraction with a concomitant drop in the S-phase fraction when compared with the untreated cells. The examination of early cellular signaling revealed that DCA but not butyrate increased intracellular reactive oxygen species, genomic DNA breakage, the activation of ERK1/2, caspase-3 and PARP. In contrast, DCA decreased activated Rb protein level, and butyrate but not DCA increased p21 expression. Collectively, although both butyrate and DCA inhibit colonic cell proliferation, butyrate increases tumor suppressor gene expression, whereas DCA decreases tumor suppressor activation in cell cycle and apoptosis pathways.
Hessian nilpotent polynomials and the Jacobian conjecture

Let z = (z 1 ,···,z n ) and let A = Σ n i=1 ∂ 2 ∂z 2 i be the Laplace operator. The main goal of the paper is to show that the well-known Jacobian conjecture without any additional conditions is equivalent to what we call the vanishing conjecture: for any homogeneous polynomial P(z) of degree d = 4, if Δ m P m (z) = 0 for all m ≥ 1, then Δ m P m+1 (z) = 0 when m > > 0, or equivalently, Δ m P m+1 (z) = 0 when m > 3 2(3 n-2 -1). It is also shown in this paper that the condition Δ m P m (z) = 0 (m ≥ 1) above is equivalent to the condition that P(z) is Hessian nilpotent, i.e. the Hessian matrix Hes P(z) = (∂ 2 P ∂z i ∂z j ) is nilpotent. The goal is achieved by using the recent breakthrough work of M. de Bondt, A. van den Essen and various results obtained in this paper on Hessian nilpotent polynomials. Some further results on Hessian nilpotent polynomials and the vanishing conjecture above are also derived.
Analyzing Trade Liberalization Effect in the Egg Sector Using a Dynamic Gravity Model

This study analyzes the effects of different liberalization scenarios in the international trade of eggs and egg products. We use a dynamic gravity model that takes into account the observed persistence of trading partners. The estimated parameters of the gravity model serve to quantify the impact of various liberalization scenarios on the probability of importing (extensive margin) and on trade volumes (intensive margin). The results indicate that even in the context of aggressive trade liberalization, trade gains at the extensive margin will be modest. Gains at the intensive margin of trade are present even in the context of partial liberalization - Doha-type - of trade.
Stereostructural studies on the 4-hydroxylated annonaceous acetogenins: Synthesis of model butenolides of known relative and absolute configuration involving an intriguing translactonization reaction

Abstract Each diastereomer of model butenolides 3 was synthesized from appropriate antipodes of two propylene oxide molecules. Concomitant translactonization reactions have important stereochemical ramifications.
Direct Risk Aversion Evidence From Risky Prospects Valued Below Their Worst Outcome

Why would people pay more for a $50 gift certificate than for the opportunity to receive a gift certificate worth either $50 or $100, with equal probability? This article examines three possible mechanisms for this recently documented uncertainty effect (UE): First, awareness of the better outcome may devalue the worse one. Second, the UE may have arisen in the original demonstration of this effect because participants misunderstood the instructions. Third, the UE may be due to direct risk aversion, that is, actual distaste for uncertainty. In Experiment 1, the UE was observed even though participants in the certainty condition were also aware of the better outcome; this result eliminates the first explanation. Experiment 2 shows that most participants understand the instructions used in the original study and that the UE is not caused by the few who do not. Overall, the experiments demonstrate that the UE is robust, large (prospects are valued at 65% of the value of the worse outcome), and widespread (at...
The ACCMM Model and the Heavy Quark Expansion

Abstract The ACCMM model predicts the lepton spectrum from B meson decay by assuming the meson disintegrates into a spectator quark of definite mass and momentum distribution and an off shell b quark whose decay leptons (boosted into the rest frame of the meson) determine the lepton spectrum. In this letter, we show that one can define a model dependent b quark mass so that the spectrum derived from the ACCMM model agrees very well with the free quark decay spectrum far from the endpoint. Near the endpoint, there is some disagreement, indicating the result is more model dependent. The integrated spectra are however very nearly identical. These results are in accordance with expectations based on the heavy quark effective theory. We conclude that for LEP experiments, free quark decay might be as general and more simple than the ACCMM ansatz for modeling the inclusive charged lepton spectrum from B meson decay.
Halo/Thick Disk CVS and the Cosmic X-Ray Background

In a recent study (Maoz and Grindlay 1995) we have found that a number of previously recognized anomalies in the diffuse x-ray background at soft energies (~0.5-2 keV) can be understood if about 20–30% of the diffuse flux arises from a population of low luminosity sources in a thick disk or flattened halo distribution in the Galaxy. Here we summarize our results and review the arguements that these objects are not accreting neutron stars or black holes but rather white dwarfs (i. e. CVs) which may have been produced in a primordial population of disrupted globular clusters.
Optomechanical and photothermal interactions in suspended photonic crystal membranes

We present here an optomechanical system fabricated with novel stress management techniques that allow us to suspend an ultrathin defect-free silicon photonic-crystal membrane above a Silicon-on-Insulator (SOI) substrate with a gap that is tunable to below 200 nm. Our devices are able to generate strong attractive and repulsive optical forces over a large surface area with simple in- and out- coupling and feature the strongest repulsive optomechanical coupling in any geometry to date (gOM/2π ≈ −65 GHz/nm). The interplay between the optomechanical and photo-thermal-mechanical dynamics is explored, and the latter is used to achieve cooling and amplification of the mechanical mode, demonstrating that our platform is well-suited for potential applications in low-power mass, force, and refractive-index sensing as well as optomechanical accelerometry.
Investment Timing with Incomplete Information and Multiple Means of Learning

We consider a firm that can use one of several costly learning modes to dynamically reduce uncertainty about the unknown value of a project. Each learning mode incurs cost at a particular rate and ...
A process for the rapid removal of dialkylamino-substituents from aromatic rings. Application to the expedient synthesis of (R)-tolterodine

A range of N,N-dialkylanilines have been successfully converted to the parent substituted benzenes by a novel two-step pathway. The products are obtained in good yields and optical purity of adjacent stereocenters is maintained. This technology has been applied toward the synthesis of (R)-tolterodine.
Why Do Fewer Agricultural Workers Migrate Now

The share of agricultural workers who migrate within the United States has fallen by approximately 60% since the late 1990s. To explain this decline in the migration rate, we estimate annual migration - choice models using data from the National Agricultural Workers Survey for 1989 – 2009. On average over the last decade of the sample, one - third of the fall in the migration rate was due to changes in the demographic composition of the workforce, while two - thirds was due to changes in coefficients (“structural” change). In some years, demographic changes were responsible for half of the overall change.
Monotone comparative statics for games with strategic substitutes

Abstract Under some conditions, parameterized games with strategic substitutes exhibit monotone comparative statics of equilibria. These conditions relate to a tradeoff between a direct parameter effect and an opposing, indirect strategic substitute effect. If the indirect effect does not dominate the direct effect, monotone comparative statics of equilibria are guaranteed. These conditions are available for best-response functions, differentiable payoff functions, and general payoff functions. Results are extended to correspondences, the analysis applies to asymmetric equilibria, and several examples are provided.
The Classical Singularity Theorems and Their Quantum Loopholes

The singularity theorems of classical general relativity are briefly reviewed. The extent to which their conclusions might still apply when quantum theory is taken into account is discussed. There are two distinct quantum loopholes: quantum violation of the classical energy conditions, and the presence of quantum fluctuations of the spacetime geometry. The possible significance of each is discussed.
A Static Evidential Network for Context Reasoning in Home-Based Care

In home-based care, reliable contextual information of remotely monitored patients should be generated by correctly recognizing the activities to prevent hazardous situations of the patient. It is difficult to achieve a higher confidence level of contextual information for several reasons. First, low-level data from multisensors have different degrees of uncertainty. Second, generated contexts can be conflicting, even though they are acquired by simultaneous operations. We propose the static evidential fusion process (SEFP) as a context-reasoning method. The context-reasoning method processes sensor data with an evidential form based on the Dezert-Smarandache theory (DSmT). The DSmT approach reduces ambiguous or conflicting contextual information in multisensor networks. Moreover, we compare SEFP based on DSmT with traditional fusion processes such as Bayesian networks and the Dempster-Shafer theory to understand the uncertainty analysis in decision making and to show the improvement of the DSmT approach compared to the others.
Recent advances in predictive (machine) learning

Prediction involves estimating the unknown value of an attribute of a system under study given the values of other measured attributes. In prediction (machine) learning the prediction rule is derived from data consisting of previously solved cases. Most methods for predictive learning were originated many years ago at the dawn of the computer age. Recently two new techniques have emerged that have revitalized the field. These are support vector machines and boosted decision trees. This paper provides an introduction to these two new methods tracing their respective ancestral roots to standard kernel methods and ordinary decision trees.
Die Attachment for −120°C to +20°C Thermal Cycling of Microelectronics for Future Mars Rovers—An Overview

Active thermal control for electronics on Mars Rovers imposes a serious penalty in weight, volume, power consumption, and reliability.
The Paradox of Law Enforcement in Immigrant Communities: Does Tough Immigration Enforcement Undermine Public Safety?

Frustrated by federal inaction on immigration reform, several U.S. states in recent years have proposed or enacted laws designed to stem the flow of illegal immigrants into the United States and to facilitate their removal. An underappreciated implication of these laws is the potential alienation of immigrant communities—even law-abiding, cooperative individuals—from the criminal justice system. The ability of the criminal justice system to detect and sanction criminal behavior is dependent upon the cooperation of the general public, including acts such as the reporting of crime and identifying suspects. Cooperation is enhanced when local residents believe that laws are enforced fairly. In contrast, research reveals that cynicism of the police and the legal system undermines individuals’ willingness to cooperate with the police and engage in the collective actions necessary to socially control crime. By implication, recent trends toward strict local enforcement of immigration laws may actually undercut pu...
Both Lymantria dispar nucleopolyhedrovirus enhancin genes contribute to viral potency

Enhancins are a group of proteins first identified in granuloviruses (GV) that have the ability to enhance nuclear polyhedrosis virus potency. We had previously identified an enhancin gene (E1) in the Lymantria dispar multinucleocapsid nucleopolyhedrovirus (LdMNPV) (D. S. Bischoff and J. M. Slavicek, J. Virol. 71:8133-8140, 1997). Inactivation of the E1 gene product within the viral genome lowered viral potency by an average of 2.9-fold. A second enhancin gene (E2) was identified when the entire genome of LdMNPV was sequenced (Kuzio et al., Virology 253:17-34, 1999). The E2 protein exhibits approximately 30% amino acid identity to the LdMNPV E1 protein as well as the enhancins from Trichoplusia ni GV, Pseudaletia unipuncta GV, Helicoverpa armigera GV, and Xestia c-nigrum GV. Northern analysis of viral RNA indicated that the E2 gene transcripts are expressed at late times postinfection from a consensus baculovirus late promoter. The effect of the enhancin proteins on viral potency was investigated through bioassay using two recombinant viruses, one with a deletion in the E2 gene (E2del) and a second with deletion mutations in both enhancin genes (E1delE2del). The enhancin gene viral constructs were verified by Southern analysis and shown not to produce enhancin gene transcripts by Northern analysis. The E2del virus exhibited an average decrease in viral potency of 1.8-fold compared to wild-type virus. In the same bioassays, the recombinant virus E1cat, which does not produce an E1 gene transcript, exhibited an average decrease in viral potency of 2.3-fold compared to control virus. The E1delE2del virus exhibited an average decrease in viral potency of 12-fold compared to wild-type virus. Collectively, these results suggest that both LdMNPV enhancin genes contribute to viral potency, that each enhancin protein can partially compensate for the lack of the other protein, and that both enhancin genes are necessary for wild-type viral potency.
The Evolving Value of Foreign Partnerships in Transitioning Economies

Through studying joint ventures during the early (1993) and late phases (2001) of Hungary's economic transition to market economy, we demonstrate how institutional and economic transformation alter...
An endomorphism of the Khovanov invariant

Abstract We construct an endomorphism of the Khovanov invariant to prove H-thinness and pairing phenomena of the invariants for alternating links. As a consequence, it follows that the Khovanov invariant of an oriented nonsplit alternating link is determined by its Jones polynomial, signature, and the linking numbers of its components.
Changing Climate, Changing Culture: Adding the Climate Change Dimension to the Protection of Intangible Cultural Heritage

This article explores the interplay between climate change and cultural heritage, in particular the intangible aspects of cultural heritage, in international legal frameworks, either existing or under development. The prime focus of the current climate change regime of the United Nations Framework Convention on Climate Change (UNFCCC) is the reduction of greenhouse gas emissions, leaving certain aspects of cultural heritage rather on the sidelines of debate and policy. However, where climate change combines with generally weak law and policy for culture and traditions, countries vulnerable to climate change may face significant cultural loss in the years to come.In its inventory of present and contemplated legal protection options, this article draws particular attention to policymaking directed at shaping a “rights-based” system in the form of sui generis rights, to complement any existing intellectual property-based protection. If adequately motivated, indigenous people have a key role to play not only in observing change, but also in developing adaptive models to cope.
New solar opacities, abundances, helioseismology, and neutrino fluxes

We construct solar models with the newly calculated radiative opacities from the Opacity Project (OP) and with recently determined (lower) heavy-element abundances. We compare the results from the new models with the predictions of a series of models that use OPAL radiative opacities, older determinations of the surface heavy-element abundances, and refinements of nuclear reaction rates. For all the variations we consider, solar models that are constructed with the newer and lower heavy-element abundances advocated by Asplund et al. disagree by much more than the estimated measuring errors with the helioseismological determinations of the depth of the solar convective zone, the surface helium composition, the internal sound speeds, and the density profile. Using the new OP radiative opacities, the ratio of the 8B neutrino flux calculated with the older and larger heavy-element abundances (or with the newer and lower heavy-element abundances) to the total neutrino flux measured by the Sudbury Neutrino Observatory is 1.09 (0.87) with a 9% experimental uncertainty and a 16% theoretical uncertainty, 1 σ errors.
Estimating risk preferences in the presence of bifurcated wealth dynamics: can we identify static risk aversion amidst dynamic risk responses?

Estimating risk preferences is tricky because controlling for confounding factors is difficult. Omitting or imperfectly controlling for these factors can attribute too much observable behaviour to risk aversion and bias estimated preferences. Agents often modify risky decisions in response to dynamic wealth or asset thresholds, where such thresholds exist. Ignoring this dynamic risk response introduces an attribution bias in static estimates of risk aversion. We demonstrate this pitfall using a simple model and a Monte Carlo simulation to explore the implications of this problem for empirical estimation. While an approach that jointly estimates risk preferences and wealth dynamics may remedy the problem by extracting dynamic risk responses from observed behaviour, it is likely to be challenging to implement in broader empirical settings for reasons we discuss. , Oxford University Press.
Scientific legacy of Robert L. Platzman. Preliminary report

Abstract One of the founders of radiation physics and chemistry, Platzman (1918–73) taught us elements of our current understanding such as the nature of the hydrated electron, the basic theory of the yield of ions and other initial-product species, and the importance of the oscillator-strength spectrum. In addition to all this seen in the literature, he left many unpublished materials, some of which contain stimulating thoughts and valuable ideas for experimental and theoretical work in the 21st century.
Counting, fanout and the complexity of quantum ACC

We propose definitions of QAC0, the quantum analog of the classical class AC0 of constant-depth circuits with AND and OR gates of arbitrary fan-in, and QACC[q], the analog of the class ACC[q] where Modq gates are also allowed. We prove that parity or fanout allows us to construct quantum MODq gates in constant depth for any q, so QACC [2] = QACC. More generally, we show that for any q, p > 1, MODq is equivalent to MODp (up to constant depth and polynomial size). This implies that QAC0 with unbounded fanout gates, denoted QACwf0, is the same as QACC [q] and QACC for all q. Since ACC[p] ≠ ACC[q] whenever p and q are distinct primes, QACC [q] is strictly more powerful than its classical counterpart, as is QAC0 when fanout is allowed. This adds to the growing list of quantum complexity classes which are provably more powerful than their classical counterparts. We also develop techniques for proving upper bounds for QACC in terms of related language classes. We define classes of languages closely related to QACC [2] and show that restricted versions of them can be simulated by polynomial-size circuits. With further restrictions, language classes related to QACC [2] operators can be simulated by classical threshold circuits of polynomial size and constant depth.
Limited observability as a constraint in contract design

Limited observability is the assumption that economic agents can only observe a finite amount of information. Given this constraint, contracts among agents are necessarily finite and incomplete in comparison to the ideal complete contract that we model as infinite in detail. We consider the extent to which finite contracts can approximate the idealized complete contracts. The objectives of the paper are:(i) to identify properties of agents’ preferences that determine whether or not finiteness of contracts causes significant inefficiency; (ii) to evaluate the performance of finite contracts against the ideal optimal contracts in principal-agent and bilateral bargaining models.
The preparation of α,α-difluoropropargylphosphonates

Abstract The organometallic reagent, (EtO) 2 P(O)CF 2 ZnBr, reacts with 1-alkynyl halides (halide=Br, I) in the presence of Cu(I)Br to give good yields of α,α-difluoropropargylphosphonates via a one pot reaction.
Conjugate reduction of quinone derivatives. A route to phenol keto-tautomer equivalents

Abstract 1,4-addition of hydride to quinone monoketals 1 and p -quinol ethers 2, mediated by bis-(2,6-di- t -butyl-4-methylphenoxy)-methylaluminum (MAD), affords 4,4-substituted-2-cyclohexen-1-ones 3, which represent keto-tautomer equivalents of phenols.
A convenient one-pot synthesis of 2-(alkylthio)isoflavones from deoxybenzoins using a phase transfer catalyst

Abstract A convenient phase transfer catalysis procedure for the synthesis of 2-(alkylthio)isoflavones is described. A number of compounds of potential pharmaceutical interest can be prepared in a single step at ambient conditions from various, easily accessible deoxybenzoins using this method.
The Importance of Systematic Observation of Persistent Meteor Trains

Abstract No Abstract Available. [Reprinted from The Observatory, No. 402, November, 1908.] September, 1908
Photonic molecules formed by coupled hybrid resonators

We describe a method that enables free-standing whispering-gallery-mode microresonators, and report spectral tuning of photonic molecules formed by coupled free and on-chip resonators with different geometries and materials. We study direct coupling via evanescent fields of free silica microtoroids and microspheres with on-chip polymer coated silica microtoroids. We demonstrate thermal tuning of resonance modes to achieve maximal spectral overlap, mode splitting induced by direct coupling, and the effects of distance between the resonators on the splitting spectra.
Chromospheric variations in main-sequence stars

The work described here is still in progress; hence this paper will be a brief sampling of the results to date.
Synthesis of the hydroxide cluster [Al13(μ3-OH)6(μ-OH)18(H2O)24]15+ from an aqueous solution.

A scalable synthesis of the “flat” tridecameric inorganic cluster [Al13(μ3-OH)6(μ-OH)18(H2O)24]15+ has been realized by treating an aqueous aluminum nitrate solution with a zinc–metal powder at room temperature. Single crystals and polycrystalline samples are readily obtained in yields exceeding 55% relative to the starting reagent Al(NO3)3. Products have been characterized by X-ray diffraction and solid-state 27Al MAS and MQMAS NMR.
Multilateral debt relief through the eyes of financial markets

This paper conducts an event study of the impact of multilateral debt relief initiatives announcements on the stock prices of South African companies with subsidiaries in countries benefited by these initiatives. It shows that these prices increase significantly above those of other firms, especially around the launching of the Multilateral Debt Relief Initiative. These price increases are consistent with lower expected levels of future taxation in the benefited countries and provide evidence of the economic consequences of multilateral debt relief that is robust to reverse causality between economic performance and the decision to grant debt relief.
The realization of symmetric switching functions using magnetic bubble technology

Since its debut in the late sixties, magnetic bubble technology has quickly evolved to become a promising alternative to semiconductor technology for computer construction. While emphasis has been placed upon the application of bubble technology to storage, its application to logic has thus far been largely limited to the implementation of simple basic operators, such as AND, OR, etc. An exception is the excellent work recently reported in References 12 and 13. This limitation to simple basic operators, however, is not in keeping with the high density and low connectivity requirements of LSI (Large-Scale Integration), and it has become increasingly important to find powerful multi-input switching functions. The symmetric function is a natural candidate. The realization of symmetric functions using magnetic bubble technology has been found to be very simple.
Making Room for China in the World Economy

As it comes out of the crisis, the world econ omy faces two apparently conflicting demands. On the one hand, achieving global macroeco nomic stability and preventing a protectionist backlash will require that we avoid large current account imbalances of the type that the world economy experienced in the run-up to the cri sis. On the other hand, returning to rapid growth in the developing nations will require that they resume their conquest of global market share in tradable goods. The challenge of meeting both demands is epitomized by the contentious US-China bilat eral relationship. American (and European) policy makers blame China for an undervalued renminbi, which they argue is the root cause of China's huge trade surplus. Chinese leaders resist the pressure, fearing that appreciation will undercut the competitiveness of Chinese goods in world markets, hurt exports, and damage growth. The Western answer to this concern is that China needs to replace foreign demand with domestic demand as the engine of growth. But if growth depends primarily on the sup ply of modern manufactured products and other tradables as opposed to services and non-trad ables, as I will argue here, the Chinese position has more force than critics give it credit. The conventional fix for China's current account surplus, consisting of a combination of expendi ture expansion and currency appreciation, will shift the structure of the economy away from tradables and towards non-tradables. This may be good for macroeconomic balance in China and elsewhere, but it will almost certainly have adverse effects on China's growth?perhaps large enough even to endanger the country's social and political stability.
A technique for comparative assessment of software development management policies

This paper describes a technique designed for organizing and structuring the comparison of software development management and software design practices. It is intended to provide a general method for assessing proposed software practices, especially of bidders on software contracts, and also to provide a visual aid in explaining to management how these proposed software practices comply with specifications, exceed specifications or are lacking.
The Preparation of Partially Oriented Zeolite Thin Films via Pulsed Laser Ablation

Thin films of zeolites including silicalite-1, mordenite and UTD-18 have been prepared on stainless steel foil via pulsed laser deposition (PLD). Laser ablation of as-synthesized zeolite targets onto stainless steel foil followed by a post hydrothermal treatment results in partially oriented zeolite thin films. SEM, XRD were used to characterize the zeolite thin films. Preliminary results for multilayercoatings of different zeolites will also be presented.
Screening Rules for Determining Blood Pressure Status in Clinical Trials Application to the Trials of Hypertension Prevention

Multistage blood pressure screening rules are often used to select subjects for clinical trials. Multiple blood pressure readings are taken over successive visits, and the subject must meet eligibility criteria at each visit. In this paper, the authors present methods which depend on the distribution of the subject's underlying blood pressure values (the predictive value approach) or, alternatively, the subject's observed mean over all screening visits (the empirical predictive value approach) given the observed mean after one or more visits. The authors apply these methods to data from Phase I of the Trials of Hypertension Prevention, which attempts to identify subjects with mean diastolic blood pressures in the range 80-89 mmHg over three screening visits. The estimated efficiency of these rules is evaluated in terms of the number of clinic screening visits needed per eligible subject. Relative to reexamining all subjects at each visit (no screening), these approaches can reduce the number of visits required by 27%. This is in contrast to the standard rule in which a subject must have an observed mean diastolic blood pressure of 80-89 mmHg on each of three consecutive visits, which requires twice as many clinic visits per eligible subject as not screening. Thus, the approach presented is useful in identifying eligible subjects for clinical trials in an efficient manner.
Phenyl Ring Dynamics in a Tetraphenylethylene-Bridged Metal–Organic Framework: Implications for the Mechanism of Aggregation-Induced Emission

Molecules that exhibit emission in the solid state, especially those known as aggregation-induced emission (AIE) chromophores, have found applications in areas as varied as light-emitting diodes and biological sensors. Despite numerous studies, the mechanism of fluorescence quenching in AIE chromophores is still not completely understood. To this end, much interest has focused on understanding the low-frequency vibrational dynamics of prototypical systems, such as tetraphenylethylene (TPE), in the hope that such studies would provide more general principles toward the design of new sensors and electronic materials. We hereby show that a perdeuterated TPE-based metal–organic framework (MOF) serves as an excellent platform for studying the low-energy vibrational modes of AIE-type chromophores. In particular, we use solid-state 2H and 13C NMR experiments to investigate the phenyl ring dynamics of TPE cores that are coordinatively trapped inside a MOF and find a phenyl ring flipping energy barrier of 43(6) kJ...
Polyhydroxyalkanoate (PHA) homeostasis: the role of the PHA synthase

Covering: 1989 to 2003 Polyhydroxyalkanoates (PHAs) are biodegradable polymers with properties of thermoplastics. Production of these polymers in an economically competitive fashion via bioengineering requires an understanding of the biosynthetic pathway and its regulation. This review summarizes our current knowledge of the mechanism of the class I and III PHA synthases: the initiation, elongation and termination processes. It also summarizes our current understanding of the phase transition from soluble substrates (coenzyme A esters of β-hydroxyalkanoates) to insoluble granules and our understanding of the requirement for a transcription factor, phasin proteins, and depolymerases in PHA homeostasis.
A Probabilistic and RIPless Theory of Compressed Sensing

This paper introduces a simple and very general theory of compressive sensing. In this theory, the sensing mechanism simply selects sensing vectors independently at random from a probability distribution F; it includes all standard models-e.g., Gaussian, frequency measurements-discussed in the literature, but also provides a framework for new measurement strategies as well. We prove that if the probability distribution F obeys a simple incoherence property and an isotropy property, one can faithfully recover approximately sparse signals from a minimal number of noisy measurements. The novelty is that our recovery results do not require the restricted isometry property (RIP) to hold near the sparsity level in question, nor a random model for the signal. As an example, the paper shows that a signal with s nonzero entries can be faithfully recovered from about s logn Fourier coefficients that are contaminated with noise.
Aeroelastic stability analysis of wind turbines using an eigenvalue approach

A design tool for performing aeroelastic stability analysis of wind turbines is presented in this paper. The method behind this tool is described in a general form, as independent of the particular aeroelastic modelling as possible. Here, the structure is modelled by a Finite beam Element Method, and the aerodynamic loads are modelled by the Blade Element Momentum method coupled with a Beddoes-Leishman type dynamic stall model in a state-space formulation. The linearization of the equations of motion is performed about a steady-state equilibrium, where the deterministic forcing of the turbine is neglected. To eliminate the periodic coefficients and avoid using the Floquet Theory, the multi-blade transformation is utilized. From the corresponding eigenvalue problem, the eigenvalues and eigenvectors can be computed at any operation condition to give the aeroelastic modal properties: Natural frequencies, damping and mode shapes. An example shows a good agreement between predicted and measured aeroelastic damping of a stall-regulated 600 kW turbine. Copyright © 2004 John Wiley & Sons, Ltd.
On the extension of the mean curvature flow

Consider a family of smooth immersions \({F(\cdot,t): M^n\to \mathbb{R}^{n+1}}\) of closed hypersurfaces in \({\mathbb{R}^{n+1}}\) moving by the mean curvature flow \({\frac{\partial F(p,t)}{\partial t} = -H(p,t)\cdot \nu(p,t)}\), for \({t\in [0,T)}\). Cooper (Mean curvature blow up in mean curvature flow, arxiv.org/abs/0902.4282) has recently proved that the mean curvature blows up at the singular time T. We show that if the second fundamental form stays bounded from below all the way to T, then the scaling invariant mean curvature integral bound is enough to extend the flow past time T, and this integral bound is optimal in some sense explained below.
HYDRAULIC/SHOCK JUMPS IN PROTOPLANETARY DISKS

In this paper, we describe the nonlinear outcome of spiral shocks in protoplanetary disks. Spiral shocks, for most protoplanetary disk conditions, create a loss of vertical force balance in the postshock region and result in rapid expansion of the gas perpendicular to the disk midplane. This expansion has characteristics similar to hydraulic jumps, which occur in incompressible fluids. We present a theory to describe the behavior of these hybrids between shocks and hydraulic jumps (shock bores) and then compare the theory to three-dimensional hydrodynamics simulations. We discuss the fully three-dimensional shock structures that shock bores produce and discuss possible consequences for disk mixing, turbulence, and evolution of solids.
Self-control, revealed preference and consumption choice

We provide a time-consistent model that addresses the preference reversals that motivate the time-inconsistency literature. The model subsumes the behavior generated by the time-inconsistency approach in finite settings but, unlike the time-inconsistent models, allows for self-control. This paper provides a brief summary of theoretical results shown elsewhere [Gul and Pesendorfer, Econometrica 69 (2001) 1403; Econometrica, (2002), in press; Rev. Econ. Stud. (2002), in press] and contrasts the predictions and welfare implications of our model and the time-inconsistent β−δ model.
GAS-DYNAMIC SHOCK HEATING OF POST-FLARE LOOPS DUE TO RETRACTION FOLLOWING LOCALIZED, IMPULSIVE RECONNECTION

We present a novel model in which shortening of a magnetic flux tube following localized, three-dimensional reconnection generates strong gas-dynamic shocks around its apex. The shortening releases magnetic energy by progressing away from the reconnection site at the Alfv´ en speed. This launches inward flows along the field lines whose collision creates a pair of gas-dynamic shocks. The shocks raise both the mass density and temperature inside the newly shortened flux tube. Reconnecting field lines whose initial directions differ by more that 100 ‐ can produce a concentrated knot of plasma hotter that 20 MK, consistent with observations. In spite of these high temperatures, the shocks convert less than 10% of the liberated magnetic energy into heat — the rest remains as kinetic energy of bulk motion. These gas-dynamic shocks arise only when the reconnection is impulsive and localized in all three dimensions; they are distinct from the slow magnetosonic shocks of the Petschek steady-state reconnection model. Subject headings: MHD — shock waves — Sun: flares