cssi/SciSciGPT-SciSciNet huggingface dataset:
Reactive transport modeling of trace elements in the water column of a stratified lake: iron cycling and metal scavenging

Abstract A simple one-dimensional reactive transport model was developed to determine the importance of the dynamics of major redox species such as iron on the distribution of trace elements in aquatic environments. The model simulates the distribution of iron and lead in the water column of a stratified lake (Paul Lake, MI) assuming a quasi steady-state is reached. The reactions described in the model include oxidation of reduced iron to colloidal ferric iron at the oxic–anoxic transition in the water column, aggregation of colloidal iron to particulate iron, and reduction of colloidal and particulate iron in the deep anoxic waters. The model includes sedimentation of both colloidal and particulate species. The cycling of lead is described by adsorption on colloidal iron, transfer to the particulate phase by aggregation, and redissolution in the deep waters during reduction of colloidal and particulate iron. Generally, this model reproduces experimental data collected during three field trips from 1994 to 1996 well. However, these calculations clearly show that the processes regulating the cycling of iron and lead in the water column are more complex than what is generally admitted. Additional reactions not considered in the model affect the transformation of Fe, and thus affect the removal of Pb. These reactions have to be fully characterized in order to predict the chemical distribution of trace elements at oxic–anoxic transitions in the water column of aquatic systems.
Systematic survey of therapeutic trials for metastatic colorectal cancer: room for improvement in the critical pathway.

Purpose The current strategy of drug development has been criticized as being highly inefficient. In 2004, the US Food and Drug Administration (FDA) released recommendations to improve this process, including a push for increased use of enrichment trials. It is unclear to what extent aspects of this “Critical Path Initiative” have been adopted in trial designs in metastatic colorectal cancer. Methods A systematic review was conducted of actively enrolling treatment trials in metastatic colorectal cancer. Trials were identified from the National Cancer Institute's clinicaltrials.gov and Investigative Drug Branch databases. Trials were categorized based on the number of prior treatments allowed, phase of the trial, agent mechanism of action, and FDA approval status of agents under investigation. Results One hundred two trials are enrolling, with a combined enrollment goal of more than 20,000 patients. Thirteen percent of trials investigated an agent not yet FDA-approved for any oncology indication. The most...
REFINING CHANDRA/ACIS SUBPIXEL EVENT REPOSITIONING USING A BACKSIDE-ILLUMINATED CCD MODEL

Subpixel event repositioning (SER) techniques have been demonstrated to significantly improve the already unprecedented spatial resolution of Chandra X-ray imaging with the Advanced CCD Imaging Spectrometer (ACIS). Chandra CCD SER techniques are based on the premise that the impact position of events can be refined, based on the distribution of charge among affected CCD pixels. ACIS SER models proposed thus far are restricted to corner split (3 and 4 pixel) events and assume that such events take place at the split-pixel corners. To improve the event-counting statistics, we modified the ACIS SER algorithms to include 2 pixel split events and single-pixel events, using refined estimates for photon impact locations. Furthermore, simulations that make use of a high-fidelity backside-illuminated (BI) CCD model demonstrate that mean photon impact positions for split events are energy dependent, leading to further modification of subpixel event locations according to event type and energy, for BI ACIS devices. Testing on Chandra CCD X-ray observations of the Orion Nebula Cluster indicates that these modified SER algorithms further improve the spatial resolution of Chandra/ACIS, to the extent that the spreading in the spatial distribution of photons is dominated by the high-resolution mirror assembly, rather than by ACIS pixelization.
Towards site-based protein functional annotations

The exact relationship between protein active centres and protein functions is unclear even after decades of intensive study. To improve functional prediction ability based on the local structures, we proposed three different methods. 1 We used Markov Random Field (MRF) to describe protein active region. 2 We developed filtering method that considers the local environment around the active sites. 3 We created multiple structure motifs by extending the motif to neighbouring residues. Our experiment results with enzyme families <40% sequence identity demonstrated that our methods reduced random matches and could improve up to 70% of the functional annotation ability (using area under curve).
The competition between simple and complex evolutionary trajectories in asexual populations.

On rugged fitness landscapes where sign epistasis is common, adaptation can often involve either individually beneficial “uphill” mutations or more complex mutational trajectories involving fitness valleys or plateaus. The dynamics of the evolutionary process determine the probability that evolution will take any specific path among a variety of competing possible trajectories. Understanding this evolutionary choice is essential if we are to understand the outcomes and predictability of adaptation on rugged landscapes. We present a simple model to analyze the probability that evolution will eschew immediately uphill paths in favor of crossing fitness valleys or plateaus that lead to higher fitness but less accessible genotypes. We calculate how this probability depends on the population size, mutation rates, and relevant selection pressures, and compare our analytical results to Wright-Fisher simulations. We find that the probability of valley crossing depends nonmonotonically on population size: intermediate size populations are most likely to follow a “greedy” strategy of acquiring immediately beneficial mutations even if they lead to evolutionary dead ends, while larger and smaller populations are more likely to cross fitness valleys to reach distant advantageous genotypes. We explicitly identify the boundaries between these different regimes in terms of the relevant evolutionary parameters. Above a certain threshold population size, we show that the probability that the population finds the more distant peak depends only on a single simple combination of the relevant parameters.
Photodissociation spectroscopy and dynamics of the vinoxy (CH{sub 2}CHO) radical

The photodissociation spectroscopy and dynamics of the vinoxy (CH{sub 2}CHO) radical have been studied using fast beam photofragment translational spectroscopy. The photodissociation cross section over the B{sup 2}A{double_prime} {l_arrow} X{sup 2}A{double_prime} band is measured, and photofragment translational energy and angular distributions are obtained at several excitation energies. For CH{sub 2}CHO, predissociation is observed over the entire band, including several transitions near the band origin which were seen previously in laser-induced fluorescence experiments. Two dissociation channels are seen: CH{sub 3} + CO and H + CH{sub 2}CO. The CH{sub 3} + CO channel was investigated in considerable detail and appears to proceed via internal conversion to the CH{sub 2}CHO ground state followed by isomerization to CH{sub 3}CO and subsequent dissociation. The translational energy distributions for this channel suggest an isomerization barrier in the range of 2 eV with respect to CH{sub 3} + CO products.
Probabilistic and worst case analyses of classical problems of combinatorial optimization in euclidean space

The classical problems reviewed are the traveling salesman problem, minimal spanning tree, minimal matching, greedy matching, minimal triangulation, and others. Each optimization problem is considered for finite sets of points in ℝd, and the feature of principal interest is the value of the associated objective function. Special attention is given to the asymptotic behavior of this value under probabilistic assumptions, but both probabilistic and worst case analyses are surveyed.
THE ECONOMICS OF OFFSHORING: THEORY AND EVIDENCE WITH APPLICATIONS TO ASIA

This paper is a non-technical survey of the literature on offshoring and outsourcing, with special focus on the relevance of this literature for Asia. We first see how and to what extent this new literature helps us understand firms' tradeoffs between outsourcing and integration, the variation in the mixes of organizational forms and the location of outsourced activities. We also explore what plausibly triggers offshoring and thereafter what determines its dynamics. Finally, we draw inferences from the existing theory and empirical work about the developmental impact of offshoring on Asia, with special attention to issues related to inequality and poverty.
Information Disclosure and the Equivalence of Prospective Payment and Cost Reimbursement

Abstract A health care provider chooses unobservable service-quality and cost-reduction efforts. The efforts produce quality and cost efficiency. An insurer observes quality and cost, and chooses how to disclose this information to consumers. The insurer also decides how to pay the provider. In prospective payment, the insurer fully discloses quality, and sets a prospective payment price. In cost reimbursement, the insurer discloses a value index, a weighted average of quality and cost efficiency, and pays a margin above cost. The first-best quality and cost efforts can be implemented by prospective payment and by cost reimbursement. Cost reimbursement with value index eliminates dumping and cream skimming. Prospective payment with quality index eliminates cream skimming.
Experimental studies of spontaneous and forced transition on an axisymmetric body

An experimental investigation of spontaneous and forced transition on a secant-ogive-nose axisymmetric body was conducted for length Reynolds numbers between 0.315X106 and 1.03xl06. Several different transition modes were observed and documented using smoke-flow visualization and hot-wire anemometry. Sound was used to control the frequency and enhance the amplitude of the disturbances in the boundary layer during the forced transition studies. Three different mechanisms of transition originate as a viscosity-conditioned Tollmien-Schlichting (T-S) instability. The evolution of these instability waves depends upon Reynolds number and the frequency and amplitude of the disturbance. A change in the nonlinear development of the secondary instability—the A-vortex structure—could be induced by changing only the amplitude of the T-S waves, keeping all other conditions constant. The frequency spectra from a hot wire placed in this flowfield show an abrupt decrease in the psd of the subharmonic of the T-S wave frequency as the amplitude of the disturbance is increased. Mean and fluctuating velocity profiles and the mean pressure distribution along the body are also presented. The results support recent theories that describe the events in the nonlinear region.
Measuring bidirectional texture reflectance with a kaleidoscope

We describe a new technique for measuring the bidirectional texture function (BTF) of a surface that requires no mechanical movement, can measure surfaces in situ under arbitrary lighting conditions, and can be made small, portable and inexpensive. The enabling innovation is the use of a tapered kaleidoscope, which allows a camera to view the same surface sample simultaneously from many directions. Similarly, the surface can be simultaneously illuminated from many directions, using only a single structured light source. We describe the techniques of construction and measurement, and we show experimental results.
Direct, iridium-catalyzed enantioselective and regioselective allylic etherification with aliphatic alcohols.

Intermolecular, enantioselective allylic substitution with alcohols[1, 2] remains an undeveloped catalytic process. Few reports have been published that describe the intermolecular allylation of aliphatic alcohols with high yield and enantioselectivity,[3] and the most selective of these systems has required copper additives.[4] The large number of α chiral ethers and oxygen heterocycles in natural products and pharmaceutical candidates makes enantioselective routes to these materials important.
Political Sophistication and Attributions of Blame in the Wake of Hurricane Katrina

The governmental response to Hurricane Katrina was widely perceived to be flawed and inadequate. However, given the number of actors involved in coordinating relief efforts, both in the private sector and at all levels of government, attributions of responsibility vary widely. Drawing on the Theory of Heterogeneous Attribution, we explore the relationship between political sophistication and assessments of blame for the delayed governmental response. Using data from a survey of Louisiana residents, we find that citizens at higher levels of sophistication are less likely to find the federal government chiefly to blame, and more likely to fault actors at the state level. Moreover, less sophisticated respondents tend to focus blame disproportionately on the president, a tendency to which the more sophisticated are not as prone.
A Comparison of Three Years of Performance for Air-to-Air Parallel Solar Heat Pump System in TECH House IV

Comparaison des performances mesurees pendant les 3 saisons de chauffe de la periode 1979-1982 du systeme de chauffage par collecteur a air et pompe a chaleur en parallele dans la maison experimentale TECH IV de l'Universite du Tennessee
Benford's law for the 3x + 1 function

We show that for most choices of an initial seed $x_0$, the sequence of the first $N$ iterates of $x_0$ under the $3x+1$ map approximately satisfies Benford's law.
Dynamically Influenced Molecular Clouds in the Nucleus of NGC 6946: Variations in the CO Isotopic Line Ratios

We present high-resolution (~5'') maps of the J = 1–0 transitions of 13CO and C18O toward the nucleus of NGC 6946 made with the Owens Valley Millimeter Array. The images are compared with existing 12CO (1–0) maps to investigate localized changes in gas properties across the nucleus. As compared with 12CO, both 13CO and C18O are more confined to the central ring of molecular gas associated with the nuclear star formation; that is, 12CO is stronger relative to 13CO and C18O away from the nucleus and along the spiral arms. The 12CO (1–0)/13CO (1–0) line ratio reaches very high values of greater than 40. We attribute the relative 13CO weakness to a rapid change in the interstellar medium (ISM) from dense star-forming cores in a central ring to diffuse, low-density molecular gas in and behind the molecular arms. This change is abrupt, occurring in less than a beam size (90 pc), about the size of a giant molecular cloud. Column densities determined from 13CO (1–0), C18O (1–0), and 1.4 mm dust continuum all indicate that the standard Galactic conversion factor, XCO, overestimates the amount of molecular gas in NGC 6946 by factors of ~3–5 toward the central ring and potentially even more so in the diffuse gas away from the central starburst. We suggest that the nuclear bar acts to create coherent regions of molecular clouds with distinct and different physical conditions. The 12CO (1–0)/13CO (1–0) line ratio in galactic nuclei can be a signpost of a dynamically evolving ISM.
Electromyographic analysis of traditional and nontraditional abdominal exercises: implications for rehabilitation and training

BACKGROUND AND PURPOSE: Performing nontraditional abdominal exercises with devices such as abdominal straps, the Power Wheel, and the Ab Revolutionizer has been suggested as a way to activate abdominal and extraneous (nonabdominal) musculature as effectively as more traditional abdominal exercises, such as the crunch and bent-knee sit-up. The purpose of this study was to test the effectiveness of traditional and nontraditional abdominal exercises in activating abdominal and extraneous musculature. SUBJECTS: Twenty-one men and women who were healthy and between 23 and 43 years of age were recruited for this study. METHODS: Surface electromyography (EMG) was used to assess muscle activity from the upper and lower rectus abdominis, external and internal oblique, rectus femoris, latissimus dorsi, and lumbar paraspinal muscles while each exercise was performed. The EMG data were normalized to maximum voluntary muscle contractions. Differences in muscle activity were assessed by one-way, repeated-measures analysis of variance. RESULTS: Upper and lower rectus abdominis, internal oblique, and latissimus dorsi muscle EMG activity were highest for the Power Wheel (pike, knee-up, and roll-out), hanging knee-up with straps, and reverse crunch inclined 30°. External oblique muscle EMG activity was highest for the Power Wheel (pike, knee-up, and roll-out) and hanging knee-up with straps. Rectus femoris muscle EMG activity was highest for the Power Wheel (pike and knee-up), reverse crunch inclined 30°, and bent-knee sit-up. Lumbar paraspinal muscle EMG activity was low and similar among exercises. DISCUSSION AND CONCLUSION: The Power Wheel (pike, knee-up, and roll-out), hanging knee-up with straps, and reverse crunch inclined 30° not only were the most effective exercises in activating abdominal musculature but also were the most effective in activating extraneous musculature. The relatively high rectus femoris muscle activity obtained with the Power Wheel (pike and knee-up), reverse crunch inclined 30°, and bent-knee sit-up may be problematic for some people with low back problems.
Beyond the black box: knowledge overlaps in software outsourcing

The black-box approach - that is, the use of formal project requirements to transfer knowledge about the application problem domain from the client to the vendor organization - has long been the mainstay of outsourced software development. We've studied 209 custom application development projects in 209 global software development organizations. We used the study results to develop detailed guidelines for improving outsourcing practice and a client-vendor knowledge congruence assessment framework. The study's key finding is that effective outsourcing requires knowledge congruence - that is, a good fit in terms of business and technical knowledge across the client-vendor dyad. This uniquely extends the notion of the product/process fit from the manufacturing management arena into the more knowledge-driven domain of software engineering.
Three-player impartial games

Abstract Past efforts to classify impartial three-player combinatorial games (the theories of Li (Internat. J. Game Theory 7 (1978) 31–36) and Straffin (College J. Math. 16 (1985) 386–394)) have made various restrictive assumptions about the rationality of one's opponents and the formation and behavior of coalitions. One may instead adopt an agnostic attitude towards such issues, and seek only to understand in what circumstances one player has a winning strategy against the combined forces of the other two. By limiting ourselves to this more modest theoretical objective, and by regarding two games as being equivalent if they are interchangeable in all disjunctive sums as far as single-player winnability is concerned, we can obtain an interesting analogue of Grundy values for three-player impartial games.
Rectovaginal fistula repair using a gracilis muscle flap.

Introduction and hypothesis This video demonstrates a technique for using a pedicled gracilis muscle flap to repair rectovaginal fistula.
The Global Force Management Data Initiative: Implementing an Enterprise Information Exchange Data Model

The U.S. Department of Defense (DoD) Joint Staff, Force Structure Directorate (J-8), along with the Office of Under Secretary of Defense for Personnel and Readiness (OUSD(P&R)) put forth the Global Force Management Data Initiative (GFM DI) with the goal of developing a reliable and maintainable enterprise data source capturing Organizational and Force Structure Construct (OFSC) information. The Global Force Management Information Exchange Data Model (GFMIEDM) was developed as an enterprise solution to enable disparate systems throughout the DoD to share force structure, manpower, and equipment data. Extensible Markup Language (XML) was chosen as the data format because it is a popular format for the interchange of data between heterogeneous systems. XML is currently being used as a wrapper around relational data, and tools have been written to validate the data against structural constraints and business rules. In this paper, we discuss the GFM DI architecture, implementation details, and integration with legacy systems.
Smoking Cessation Intervention on Facebook: Which Content Generates the Best Engagement?

Background: Social media offer a great opportunity to deliver smoking cessation treatment to young adults, but previous online and social media interventions targeting health behavior change have struggled with low participant engagement. We examined engagement generated by content based on the Transtheoretical Model of Behavior Change (TTM) in a motivationally tailored smoking cessation intervention on Facebook. Objective: This study aimed to identify which intervention content based on the TTM (Decisional Balance and 10 processes of change) generated the highest engagement among participants in pre-action stages of change (Precontemplation, Contemplation, and Preparation). Methods: Participants (N=79, 20% female, mean age 20.8) were assessed for readiness to quit smoking and assigned to one of 7 secret Facebook groups tailored to their stage of change. Daily postings to the groups based on TTM Decisional Balance and the 10 processes of change were made by research staff over 3 months. Engagement was operationalized as the number of participant comments to each post. TTM content-based predictors of number of comments were analyzed and stratified by baseline stage of change, using negative binomial regression analyses with and without zero inflation. Results: A total of 512 TTM-based posts generated 630 individual comments. In Precontemplation and Contemplation groups, Decisional Balance posts generated above average engagement ( P =.01 and P <.001). In Contemplation groups, posts based on the TTM processes Dramatic Relief and Self-Liberation resulted in below average engagement ( P =.01 and P =.005). In Preparation groups, posts based on Consciousness Raising generated above average engagement ( P =.009). Participant engagement decreased over time and differed between groups within Precontemplation and Contemplation stages, but was independent of day of the week and time of day the content was posted to the groups. No participant baseline characteristics significantly predicted engagement. Conclusions: Participants not ready to quit in the next 30 days (in Precontemplation or Contemplation) engaged most when prompted to think about the pros and cons of behavior change, while those in the Preparation stage engaged most when posts increased awareness about smoking and smoking cessation. Findings support tailoring intervention content to readiness to quit and suggest intervention components that may be most effective in generating high participant engagement on social media. [J Med Internet Res 2015;17(11):e244]
Frequency-response calculations with a programmable calculator:

This paper describes an algorithm with which the user can compute frequency responses on a small pro grammable calculator. Inexpensive calculators like the Hewlett-Packard 25 allow such calculations for a system containing as many as four poles and zeros. The user must enter the proper sequence for a pole or zero, but the process is simple; the user does not have to depend on (and wait for) a large computer. The paper presents the solution of a typical problem.
L’imaginaire fantastique chez Nodier et l’inspiration biblique

Cette article interroge sur l’utilisation des images bibliques au sein de l’œuvre de Charles Nodier, pionnier du conte fantastique en France. D’apres une approche comparee les images bibliques originales sont confrontees avec les images transposees au sein du recit fantastique. L’analyse s’interesse a la conjonction entre narration, emprunt des images bibliques et le resultat de cet emprunt dans une image modifiee qui fait reference a l’image original tout en participant dans un nouveau reseau de signification. L’intertextualite des emprunts temoigne d’une creativite litteraire qui s’exprime dans une nouvelle cosmogonie fantastique qui n’hesite pas a se servir d’un monde biblique afin de faconner une nouvelle interpretation du surnaturel.
"One size fits all": an idea whose time has come and gone

The last 25 years of commercial DBMS development can be summed up in a single phrase: "one size fits all". This phrase refers to the fact that the traditional DBMS architecture (originally designed and optimized for business data processing) has been used to support many data-centric applications with widely varying characteristics and requirements. In this paper, we argue that this concept is no longer applicable to the database market, and that the commercial world will fracture into a collection of independent database engines, some of which may be unified by a common front-end parser. We use examples from the stream-processing market and the data-warehouse market to bolster our claims. We also briefly discuss other markets for which the traditional architecture is a poor fit and argue for a critical rethinking of the current factoring of systems services into products.
Trapping of gyrotactic organisms in an unstable shear layer

To explore new mechanisms for planktonic thin layer formation, particle and continuum models of gyrotactically swimming phytoplankton are embedded in simulations of a dynamically unstable stratified shear layer. Two trapping mechanisms are observed in the developing Kelvin–Helmholtz (K–H) billow train. Within the K–H billows, a particle can remain preferentially in downwelling regions, cancelling its upward swimming motion. In the braids that separate the billows, intense shear defeats the gyrotactic stabilization mechanism and causes cells to tumble. Particle and continuum models are compared statistically to reveal both consistencies and weaknesses in each. A scaling based on Reynolds number and swimming speed is used to predict the maximum concentration generated by an instability event. Although K–H billows are short lived in comparison with planktonic thin layers observed in the coastal oceans, the resulting trapping causes rapid aggregation. We conclude that trapping in a growing K–H instability could contribute to the development of the observed cell concentrations.
Measurements and modeling of total solar irradiance in X-class solar flares

The Total Irradiance Monitor (TIM) from NASA's SOlar Radiation and Climate Experiment can detect changes in the total solar irradiance (TSI) to a precision of 2 ppm, allowing observations of variations due to the largest X-class solar flares for the first time. Presented here is a robust algorithm for determining the radiative output in the TIM TSI measurements, in both the impulsive and gradual phases, for the four solar flares presented in Woods et al., as well as an additional flare measured on 2006 December 6. The radiative outputs for both phases of these five flares are then compared to the vacuum ultraviolet (VUV) irradiance output from the Flare Irradiance Spectral Model (FISM) in order to derive an empirical relationship between the FISM VUV model and the TIM TSI data output to estimate the TSI radiative output for eight other X-class flares. This model provides the basis for the bolometric energy estimates for the solar flares analyzed in the Emslie et al. study.
Capacity analysis for continuous alphabet channels with side information, part II: MIMO channels

In this second part of our two-part paper, we consider the capacity analysis for wireless mobile systems with multiple-antenna architectures. We apply the results of the first part to a commonly known baseband, discrete-time multiple-antenna system where both the transmitter and receiver know the channel's statistical law. We analyze the capacity for additive white Gaussian noise (AWGN) channels, fading channels with full channel state information (CSI) at the receiver, fading channels with no CSI, and fading channels with partial CSI at the receiver. For each type of channels, we study the capacity value as well as issues such as the existence, uniqueness, and characterization of the capacity-achieving measures for different types of moment constraints. The results are applicable to both Rayleigh and Rician fading channels in the presence of arbitrary line-of-sight and correlation profiles.
The Inverse of the Cumulative Standard Normal Probability Function

Some properties of the inverse of the function $N\lpar x\rpar = \lpar1/\sqrt{2\pi}\rpar \vint_{-\infty}^{x}e^{-t^2/2}\,\hbox{d}t$ are studied. Its derivatives, integrals and asymptotic behavior are presented.
Rationalizable Partition-Confirmed Equilibrium

Rationalizable partition-conrme d equilibrium (RPCE) describes the steady state outcomes of rational learning in extensive-form games, when rationality is common knowledge and players observe a partition of the terminal nodes. RPCE allows players to make inferences about unobserved play by others; We discuss the implications of this using numerous examples, and discuss the relationship of RPCE to other solution concepts in the literature.
The Relationship between Stellar Light Distributions of Galaxies and Their Formation Histories

A major problem in extragalactic astronomy is the inability to distinguish in a robust, physical, and modelindependent way how galaxy populations are physically related to each other and to their formation histories. A similar, but distinct, and also long-standing question is whether the structural appearances of galaxies, as seen through their stellar light distributions, contain enough physical information to offer this classification. We argue through the use of 240 images of nearby galaxies that three model-independent parameters measured on a single galaxy image reveal its major ongoing and past formation modes and can be used as a robust classification system. These parameters quantitatively measure: the concentration (C), asymmetry (A), and clumpiness (S) of a galaxy’s stellar light distribution. When combined into a threedimensional ‘‘ CAS ’’ volume all major classes of galaxies in various phases of evolution are cleanly distinguished. We argue that these three parameters correlate with important modes of galaxy evolution: star
Optimal Hitting Sets for Combinatorial Shapes

We consider the problem of constructing explicit Hitting sets for Combinatorial Shapes, a class of statistical tests first studied by Gopalan, Meka, Reingold, and Zuckerman (STOC 2011). These generalize many well-studied classes of tests, including symmetric functions and combinatorial rectangles. Generalizing results of Linial, Luby, Saks, and Zuckerman (Combinatorica 1997) and Rabani and Shpilka (SICOMP 2010), we construct hitting sets for Combinatorial Shapes of size polynomial in the alphabet, dimension, and the inverse of the error parameter. This is optimal up to polynomial factors. The best previous hitting sets came from the Pseudorandom Generator construction of Gopalan et al., and in particular had size that was quasipolynomial in the inverse of the error parameter.
The Central Role of Entrepreneurs in Transition Economies

“All sorts of small enterprises boomed in the countryside, as if a strange army appeared suddenly from nowhere,” remarked Deng Xiaoping, reflecting in 1987 on the first eight years of China’s economic reforms (Zhou 1996: 106). These startup firms drove China’s reform momentum; they were arguably the single main source of China’s growth. But their rapid emergence, Deng said, “was not something I had thought about. Nor had the other comrades. This surprised us.” The reformers had not foreseen the key to their own reforms.
REGIONAL WELFARE PROGRAMS AND LABOR FORCE PARTICIPATION

Welfare program dependency and expenditures rise during recessions, while income tax revenues from working people fall. Thus, now that states are responsible for their own welfare programs, they need to know how responsive their citizens are to workplace and safety net opportunities. This paper investigates household welfare program and labor force participation behavior. A choice-theoretic model is developed and estimated for each of the four census regions (Northeast, Midwest, South, and West) using cross-sectional data on households, labor markets, and policies. We show that household responses to welfare program parameters do differ regionally. But we find that labor supply does not depend on welfare program participation or program payoffs. Furthermore, unlike under the previous welfare program, participation in Temporary Assistance for Needy Families (TANF) does not significantly reduce household labor supply. The finding of significant differences across regions justifies the efficiency rationale for the devolution of authority to the states. We also discuss how states may be able to contain expenditures on welfare programs.
Acoustic black holes: horizons, ergospheres and Hawking radiation

It is a deceptively simple question to ask how acoustic disturbances propagate in a non-homogeneous flowing fluid. Subject to suitable restrictions, this question can be answered by invoking the language of Lorentzian differential geometry. This paper begins with a pedagogical derivation of the following result: if the fluid is barotropic and inviscid, and the flow is irrotational (though possibly time dependent), then the equation of motion for the velocity potential describing a sound wave is identical to that for a minimally coupled massless scalar field propagating in a (3 + 1)-dimensional Lorentzian geometry The acoustic metric governing the propagation of sound depends algebraically on the density, flow velocity, and local speed of sound. Even though the underlying fluid dynamics is Newtonian, non-relativistic, and takes place in flat space plus time, the fluctuations (sound waves) are governed by an effective (3 + 1)-dimensional Lorentzian spacetime geometry. This rather simple physical system exhibits a remarkable connection between classical Newtonian physics and the differential geometry of curved (3 + 1)-dimensional Lorentzian spacetimes, and is the basis underlying a deep and fruitful analogy between the black holes of Einstein gravity and supersonic fluid flows. Many results and definitions can be carried over directly from one system to another. For example, it will be shown how to define the ergosphere, trapped regions, acoustic apparent horizon, and acoustic event horizon for a supersonic fluid flow, and the close relationship between the acoustic metric for the fluid flow surrounding a point sink and the Painleve-Gullstrand form of the Schwarzschild metric for a black hole will be exhibited. This analysis can be used either to provide a concrete non-relativistic analogy for black-hole physics, or to provide a framework for attacking acoustics problems with the full power of Lorentzian differential geometry.
The temporalities of capitalism

The temporalities of capitalism are in certain respects unique. The temporalities of social life in general are 'eventful', i.e. irreversible, contingent, uneven, discon- tinuous and transformational. Although capitalist social processes are in certain respects super-eventful, the extreme abstraction that is a signature of capitalist development enables core processes of capitalism to escape from the irreversibil- ity of time and to sustain a recurrent logic at their core. This means that the tem- porality of capitalism is composite and contradictory, simultaneously still and hyper-eventful. Recognizing this contradiction at the core of capitalism poses important conceptual and methodological challenges for those who study it. Mainline quantitative American social scientists, the economists foremost among them, have tended to see time as a kind of neutral Newtonian grid in which social processes are determined by variables that act upon each other by a smooth, predictable, gradual and linear social gravity (Abbott, 1988). An eventful temporality—the kind of temporality taken for granted by most historians— would imply that social processes are, instead, lumpy, unpredictable, uneven and discontinuous. Although historians are generally reticent about engaging in explicit theoretical discourse, they have a highly sophisticated and nuanced implicit conceptualization of temporality. They see time as fateful, as irreversible in the sense that a significant action, once taken, or an event, once experienced, irrevocably alters the situation in which it occurs. The conceptual vehicle histor- ians use to construct or analyse the temporal fatefulness and contingency of social life is the event. Historians see the flow of social life as being punctuated by sig- nificant happenings, by complexes of social action that somehow change the † This paper will be part of the SYMPOSIUM: How History Matters.
An illumination planner for Lambertian polyhedral objects

The measurement of shape is a basic object inspection task. We use a noncontact method to determine shape called photometric stereo. The method uses three light sources which sequentially illuminate the object under inspection and a video camera for taking intensity images of the object. A significant problem with using photometric stereo is determining where to place the 3 light sources and the video camera. In order to solve this problem, we have developed an illumination planner that determines how to position the three light sources and the video camera around the object. The planner determines how to position light sources around an object so that we illuminate a specified set of faces in an efficient manner and so that we obtain an accurate measurement. From a high level, our planner has three major inputs: the CAD model of the object to be inspected, a noise model for our sensor, and a reflectance model for the object to be inspected. We have experimentally verified that the plans generated by the planner are valid and accurate.
DYNAMICAL CONSTRAINTS ON THE MASSES OF THE NUCLEAR STAR CLUSTER AND BLACK HOLE IN THE LATE-TYPE SPIRAL GALAXY NGC 3621

NGC 3621 is a late-type (Sd) spiral galaxy with an active nucleus, previously detected through mid-infrared [Ne V] line emission. Archival Hubble Space Telescope (HST) images reveal that the galaxy contains a bright and compact nuclear star cluster. We present a new high-resolution optical spectrum of this nuclear cluster, obtained with the Echellette Spectrograph and Imager at the Keck Observatory. The nucleus has a Seyfert 2 emission-line spectrum at optical wavelengths, supporting the hypothesis that a black hole (BH) is present. The line-of-sight stellar velocity dispersion of the cluster is σ = 43 ± 3 km s–1, one of the largest dispersions measured for any nuclear cluster in a late-type spiral galaxy. Combining this measurement with structural parameters measured from archival HST images, we carry out dynamical modeling based on the Jeans equation for a spherical star cluster containing a central point mass. The maximum BH mass consistent with the measured stellar velocity dispersion is 3 × 106 M☉. If the BH mass is small compared with the cluster's stellar mass, then the dynamical models imply a total stellar mass of ~1 × 107 M☉, which is consistent with rough estimates of the stellar mass based on photometric measurements from HST images. From the structural decomposition of Two Micron All Sky Survey images, we find no clear evidence for a bulge in NGC 3621; the galaxy contains at most a very faint and inconspicuous pseudobulge component (MK –17.6 mag). NGC 3621 provides one of the best demonstrations that very late-type spirals can host both active nuclei and nuclear star clusters, and that low-mass BHs can occur in disk galaxies even in the absence of a substantial bulge.
Is Deliberative Democracy a Falsifiable Theory

To further dialogue between theory and research on deliberative democracy, I advocate abandoning tests of deliberative theory per se and instead developing “middle-range” theories that are each important, specifiable, and falsifiable parts of deliberative democratic theory. By replacing vaguely defined entities with more concrete, circumscribed concepts, and by requiring empirically and theoretically grounded hypotheses about specific relationships between those concepts, researchers may come to understand which elements of the deliberative experience are crucial to particular valued outcomes.
Enantioselective total synthesis of (+)-cassiol.

An enantioselective total synthesis of (+)-cassiol is reported. The complex derived from Pd2(pmdba)3 and enantiopure t-BuPHOX ligand catalyzes enantioconvergent decarboxylative alkylation to generate the quaternary carbon stereocenter at an early stage. The overall synthetic strategy involves a convergent late-stage coupling of two fragments. The synthesis features a longest linear sequence of eight steps.
Transition to adult care: experiences and expectations of adolescents with a chronic illness

Background Effective means of transitioning adolescent patients with chronic illness from paediatric to adult medical care are poorly documented and supported by limited evidence. The purpose of this study is to describe expectations and concerns of adolescents with chronic illness regarding transition from subspecialty paediatric to adult-centred care during the transition process in order guide effective programme design and implementation. Methods Qualitative content and thematic analysis of semi-structured individual interviews with 22 adolescents with chronic illness, including cystic fibrosis, sickle cell disease, juvenile rheumatoid arthritis, and inflammatory bowel disease. Interviews took place at 1–3 time points over an 18-month study period. Results Transition topics included: timing of transfer to adult care, the transition process, attitudes about transition, and factors that might aid transition. During the study period, one-third of participants made the transition to adult-oriented health care. All participants who had transitioned to adult-oriented care reported participating in a structured transition programme. Concerns of those who had not initiated the transition process centred on re-establishing relationships and bringing a new team ‘up to speed’. Most adolescents anticipating transfer to adult care identified only downsides and felt unprepared to transition at the time of the interview. Subjects who had transitioned noted benefits of the adult-oriented system, even if they had been ambivalent prior to transfer of care. Participants suggested that earlier discussions about transition, opportunities to meet new healthcare teams and visits to adult-oriented venues prior to transition might aid in the transition process. Conclusions Subspecialty paediatric providers should anticipate common fears and concerns of adolescents and discuss the benefits of transfer to adult-oriented care. Further evaluation of existing transition programmes is an area for future study and is necessary for improvement of the continuum of care for adolescents with chronic medical conditions.
Regio- and stereoselective synthesis of isoindolin-1-ones via electrophilic cyclization.

A variety of substituted isoindolin-1-ones are readily prepared in good to excellent yields under very mild reaction conditions by the reaction of o-(1-alkynyl)benzamides with ICl, I2, and NBS. In a few cases, substituted isoquinolin-1-ones were obtained as the major product instead. This methodology accommodates various alkynyl amides and functional groups and has been successfully extended to heterocyclic starting materials. This chemistry has been successfully applied to the synthesis of a biologically interesting alkaloid, cepharanone B.
Measuring the Environmental Impacts of Technical Progress in Low-income Agriculture: Empirical Evidence on Irrigation Development and Forest Pressure in Palawan, the Philippines

Data from the Philippines are used to measure impacts of technical progress in lowland agriculture on upland forests. Irrigation development, labor demand, and employment are studied. Total annual labor use increased following irrigation. Employment of household members living along forest margins increased also. Time allocation data from the uplands show that increases in employment among households living along the forest margin were accompanied by reductions in forest clearing and forest-degrading activities. Empirical findings show irrigation-induced increases in agricultural employment can reduce pressure on tropical forests. Implications for policies and trends in use of labor saving methods that could undermine the observed changes are discussed.
Electricity sector restructuring and competition: lessons learned

ABTRACT We now have over a decade of experience with the privatization, restructuring, regulatory reform, and wholesale and retail competition in electricity sectors around the world. The objectives and design attributes of these reform programs are reviewed. The improvements in sector performance that have been achieved are discussed. The nature and sources of performance problems are also reviewed. Several lessons learned from this experience are identified and their implications for successful ongoing electricity reform initiatives presented. Electricity sector restructuring, regulatory reform and competition initiatives can yield significant consumer benefits when these reforms are designed and implemented well. Applying the lessons learned from recent experience can yield larger consumer benefits in the future.
CARRIER DIFFERENTIAL GPS FOR REAL-TIME CONTROL OF LARGE FLEXIBLE STRUCTURES.

Current laboratory tests demonstrate vibration and orientation control of a highly flexible vehicle using only the GPS carrier to measure motion. A 30 ft long test structure has been constructed that is suspended from above, and moves in a manner analogous to that of a flexible orbiting platform. Experiments show simultaneous rigid-body orientation and elastic vibration control by closing a feedback loop from the GPS differential carrier phase (DCP) measurements to onboard thrusters. Use of the subcentimeter-level differential position information in DCP measurements is challenging because of inherent, and arbitrarily large, measurement biases (cycle ambiguities). This paper presents a new bias ambiguity resolution algorithm that combines measurements taken during motion of the structure with a model of the platform dynamics to initialize the unknown biases. The techniques presented are applicable to systems that exhibit relative motions with frequencies ( 1 cm) that are detectable by current receivers.
Credit Crises, Precautionary Savings, and the Liquidity Trap

We use a model a la Bewly-Huggett-Ayagari to explore the eects of a credit crunch on consumer spending. Households borrow and lend to smooth idiosyncratic income shocks facing an exogenous borrowing constraint. We look at the economy response after an unexpected permananent tightening of this constraint. The interest rate drops sharply in the short run and then adjusts to a lower steady state level. This is due to the fact that after the shock a large fraction of agents is far below their target holdings of precautionary savings and this generates a large temporary positive shock to net lending. We then look at the eects on output. Here two opposing forces are present, as households can deleverage in two ways: by consuming less and by working more. We show that under a reasonable parametrization the eect on consumer spending dominates and precautionary behavior generates a recession. If we add nominal rigidities two things happen: (i) supply-side responses are muted, and (ii) there is a lower bound on the interest rate adjustment. These two elements tend to amplify the recession caused by the credit tightening.