cssi/SciSciGPT-SciSciNet huggingface dataset:
Every Linear Threshold Function has a Low-Weight Approximator

Given any linear threshold function f on n Boolean variables, we construct a linear threshold function g which disagrees with f on at most an ? fraction of inputs and has integer weights each of magnitude at most $${\sqrt{n}\cdot}2^{{\tilde{O}}(1/ \epsilon^{2})}$$ We show that the construction is optimal in terms of its dependence on n by proving a lower bound of $$\Omega(\sqrt{n})$$ on the weights required to approximate a particular linear threshold function. We give two applications. The first is a deterministic algorithm for approximately counting the fraction of satisfying assignments to an instance of the zero-one knapsack problem to within an additive ? ?. The algorithm runs in time polynomial in n (but exponential in $${1}/{\epsilon^{2}}$$ ). In our second application, we show that any linear threshold function f is specified to within error ? by estimates of its Chow parameters (degree 0 and 1 Fourier coefficients) which are accurate to within an additive $$\pm{1}/({n}\cdot 2^{{\tilde{O}}(1/ \epsilon^{2})})$$ . This is the first such accuracy bound which is inverse polynomial in n, and gives the first polynomial bound (in terms of n) on the number of examples required for learning linear threshold functions in the "restricted focus of attention" framework.
Gold-Catalyzed and N-Iodosuccinimide-Mediated Cyclization of γ-Substituted Allenamides

Chiral gamma-substituted allenamides have been shown to undergo efficient gold-catalyzed and N-iodosuccinimide-mediated cyclization to highly functionalized dihydrofurans. These reactions proceed rapidly and without loss of stereochemistry.
Co-optation & Clientelism: Nested Distributive Politics in China’s Single-Party Dictatorship

What explains the persistent growth of public employment in reform-era China despite repeated and forceful downsizing campaigns? Why do some provinces retain more public employees and experience higher rates of bureaucratic expansion than others? Among electoral regimes, the creation and distribution of public jobs is typically attributed to the politics of vote buying and multi-party competition. Electoral factors, however, cannot explain the patterns observed in China’s single-party dictatorship. This study highlights two nested factors that influence public employment in China: party co-optation and personal clientelism. As a collective body, the ruling party seeks to co-opt restive ethnic minorities by expanding cadre recruitment in hinterland provinces. Within the party, individual elites seek to expand their own networks of power by appointing clients to office. The central government’s professed objective of streamlining bureaucracy is in conflict with the party’s co-optation goal and individual elites’ clientelist interest. As a result, the size of public employment has inflated during the reform period despite top-down mandates to downsize bureaucracy.
A note on the spectral area of Toeplitz operators

In this note, we show that for hyponormal Toeplitz operators, there exists a lower bound for the area of the spectrum. This extends the known estimate for the spectral area of Toeplitz operators with an analytic symbol.
Iron-Based Catalysts for the High-Temperature Water–Gas Shift (HT-WGS) Reaction: A Review

This article critically reviews the literature on iron-based catalysts for the high-temperature water–gas shift (HT-WGS) reaction. The reaction mechanism, reaction intermediates, rate-determining step, kinetics, active site, and promoters are covered. Unlike the low-temperature water–gas shift (LT-WGS) reaction by Cu/ZnO catalysts that has received intensive analysis with modern in situ and operando spectroscopy and DFT studies, the corresponding HT-WGS reaction by Fe-based catalysts still lacks a fundamental understanding because of the absence of modern catalysis studies of this important catalytic system. Given the role of the WGS catalysts on production of H2 for a hydrogen economy, it is imperative that the fundamental molecular-level understanding of the HT-WGS catalyst be advanced.
Electron channeling patterns

La technique de canalisation des electrons permet une determination rapide dans le microscope electronique a balayage de la cristallinite d'un materiau et, dans le cas d'un materiau cristallin, du type de l'orientation, de l'espacement et de la qualite de son reseau. Deux autres techniques d'obtention d'informations cristallographiques dans le microscope electronique a balayage sont mentionnees: les diagrammes de retrodiffusion d'electrons et les diagrammes de Kossel
Proving termination with Multiset Orderings

A common tool for proving the termination of programs is the well-founded set, a set ordered in such a way as to admit no infinite descending sequences. The basic approach is to find a termination function that maps the values of the program variables into some well-founded set, such that the value of the termination function is continually reduced throughout the computation. All too often, the termination functions required are difficult to find and are of a complexity out of proportion to the program under consideration. However, by providing more sophisticated well-founded sets, the corresponding termination functions can be simplified.
An Extension of MacMahon's Equidistribution Theorem to Ordered Multiset Partitions

A classical result of MacMahon states that inversion number and major index have the same distribution over permutations of a given multiset. In this work, we prove a strengthening of MacMahon's theorem originally conjectured by Haglund. Our result can be seen as an equidistribution theorem over the ordered partitions of a multiset into sets, which we call ordered multiset partitions. Our proof is bijective and involves a new generalization of Carlitz's insertion method. This generalization leads to a new extension of Macdonald polynomials for hook shapes. We use our main theorem to show that these polynomials are symmetric and we give their Schur expansion.
“Anybody on this list that you're more worried about?” Qualitative analysis exploring the functions of questions during end of shift handoffs

Background Shift change handoffs are known to be a point of vulnerability in the quality, safety and outcomes of healthcare. Despite numerous efforts to improve handoff reliability, few interventions have produced lasting change. Although the opportunity to ask questions during patient handoff has been required by some regulatory bodies, the function of questions during handoff has been less well explored and understood. Objective To investigate questions and the functions they serve in nursing and medicine handoffs. Research design Qualitative thematic analysis based on audio recordings of nurse-to-nurse, medical resident-to-resident and surgical intern-to-intern handoffs. Subjects Twenty-seven nurse handoff dyads and 18 medical resident and surgical intern handoff dyads at one VA Medical Center. Results Our analysis revealed that the vast majority of questions were asked by the Incoming Providers. Although topics varied widely, the bulk of Incoming Provider questions requested information that would best help them understand individual patient conditions and plan accordingly. Other question types sought consensus on clinical reasoning or framing and alignment between the two professionals. Conclusions Handoffs are a type of socially constructed work. Questions emerge with some frequency in virtually all handoffs but not in a linear or predictable way. Instead, they arise in the moment, as necessary, and without preplanning. A checklist cannot model this process element because it is a static memory aid and questions occur in a relational context that is emergent. Studying the different functions of questions during end of shift handoffs provides insights into the interface between the technical context in which information is transferred and the social context in which meaning is created.
Mantle Rayleigh waves from the Kamchatka earthquake of November 4, 1952*

Abstract Mantle Rayleigh waves from the Kamchatka earthquake of November 4, 1952, are analyzed. The new Palisades long-period vertical seismograph recorded orders R 6 –R 15 , the corresponding paths involving up to seven complete passages around the earth. The dispersion data for periods below 400 sec. are in excellent agreement with earlier results and can be explained in terms of the known increase of shear velocity with depth in the mantle. Data for periods 400-480 sec. indicate a tendency for the group velocity curve to level off, suggesting that these long waves are influenced by a low or vanishing shear velocity in the core. Deduction of internal friction in the mantle from wave absorption gives a value 1/ Q = 370 × 10 −5 for periods 250-350 sec. This is a little over half the value reported earlier for periods 140-215 sec.
Psychiatry's sickness and its biological cure.

(1997). Psychiatry’s Sickness and Its Biological Cure. Psychiatry: Vol. 60, No. 1, pp. 89-99.
Decrease in Candida bloodstream infections in veterans in Atlanta.

Despite the recent focus on prevention of health care–associated infections, rates of Candida bloodstream infections in adults have remained unchanged until recently. We report a decline of Candida bloodstream infections, not explained by changes in broad-spectrum antibiotic use, but coinciding with infection control policies aimed at central venous catheter maintenance.
Cystatin C as a predictive marker of renal dysfunction and mid-term outcomes following off-pump coronary artery bypass grafting

Objective To determine whether plasma cystatin C and creatinine levels after isolated off-pump coronary artery bypass grafting (OPCAB) are predictive of postoperative renal dysfunction and clinical outcomes. Methods Between January 2008 and December 2013, 1033 who underwent isolated OPCAB were recruited. The patients were divided into three groups according to the preoperative level of cystatin C: low (0.83 mg/L>), mid (0.83–1.13 mg/L) and high (1.13 mg/L Results Follow-up was complete in all of the included patients at a mean of 2.9±1.5 years. Within the follow-up period, 9 early (30-day mortality) and 46 late deaths occurred. The 30-day mortality was zero, four (44%), and five (56%) cases in low, mid and high groups, respectively (p=0.03). The cut-off value of cystatin C for renal dysfunction prediction was approximately 1.04 (mg/L, p Conclusions Cystatin C is a stronger predictor of postoperative renal dysfunction than serum creatinine, and its level is directly correlated with mid-term OPCAB adverse results.
Gradient Nonlinear Pancharatnam-Berry Metasurfaces

We apply the Pancharatnam-Berry phase approach to plasmonic metasurfaces loaded by highly nonlinear multiquantum-well substrates, establishing a platform to control the nonlinear wave front at will based on giant localized nonlinear effects. We apply this approach to design flat nonlinear metasurfaces for efficient second-harmonic radiation, including beam steering, focusing, and polarization manipulation. Our findings open a new direction for nonlinear optics, in which phase matching issues are relaxed, and an unprecedented level of local wave front control is achieved over thin devices with giant nonlinear responses.
Practice Guidelines and Tort Reform: The Legal System Confronts the Technocratic Wish

Recent scholarly writing has argued that the advent of managed care within the health policy arena can be seen as a contemporary manifestation of a broader set of concerns focusing on how objective decision procedures become politically legitimated--what one recent commentator has characterized as a faith in the technocratic wish. In the 1990s, this faith in objective decision procedures has manifested itself through the emergence of outcomes assessment and the development of practice guidelines. Notably, a few states have sought to couple the practice guidelines movement with tort reform by enacting demonstration projects permitting physicians to introduce evidence that they followed practice guidelines as an affirmative defense. In this article, I argue that even though the introduction of practice guidelines may promote the policy objective of cost-effectiveness in the delivery of health care services, their use to establish culpability in actual cases may be more difficult because the structure of legal reasoning focuses on the particular facts in the case at hand rather than appealing to abstract decision procedures. By highlighting the potential difficulties of invoking practice guidelines in the adjudication of actual malpractice cases, I demonstrate how a process of ongoing political negotiation will be necessary if the technocratic faith in practice guidelines is to become justified in reality.
Effect of Stagger on the Vibroacoustic Loads from Clustered Rockets

The effect of stagger startup on the vibroacoustic loads that form during the end-effects regime of clustered rockets is studied using both full-scale (hot-gas) and laboratory-scale (cold-gas) data with vehicle geometry. Both configurations comprise three nozzles with thrust-optimized parabolic contours that undergo free-shock separated flow and restricted-shock separated flow as well as an end-effects regime before flowing full. Acoustic pressure waveforms recorded at the base of the nozzle cluster are analyzed using various statistical metrics as well as time-frequency analysis. The findings reveal a significant reduction in end-effects regime loads when engine startups are staggered. However, regardless of stagger, both the skewness and kurtosis of the acoustic pressure time derivative elevate to the same levels, thereby demonstrating the intermittence and impulsiveness of the acoustic waveforms during the end-effects regime.
Enhancing and Customizing Laboratory Information Systems to Improve/Enhance Pathologist Workflow

Optimizing pathologist workflow can be difficult because it is affected by many variables. Surgical pathologists must complete many tasks that culminate in a final pathology report. Several software systems can be used to enhance/improve pathologist workflow. These include voice recognition software, pre-sign-out quality assurance, image utilization, and computerized provider order entry. Recent changes in the diagnostic coding and the more prominent role of centralized electronic health records represent potential areas for increased ways to enhance/improve the workflow for surgical pathologists. Additional unforeseen changes to the pathologist workflow may accompany the introduction of whole-slide imaging technology to the routine diagnostic work.
Conceivability, Explanation, and Defeat

Christopher Hill and Joseph Levine have argued that the conceivabilitiesinvolved in anti-materialist arguments are defeated as evidence ofpossibility. Their strategy assumes the following principle: theconceivability of a state of affairs S constitutes evidence for thepossibility of S only if the possibility of S is the bestexplanation of the conceivability of S. So if there is a betterexplanation of the conceivability of S than its possibility, then theconceivability of S is thereby defeated as evidence of possibility. Hilland Levine proceed to offer alternative explanations of theseconceivabilities, concluding that these conceivabilities are therebydefeated as evidence. However, this strategy fails because theirexplanations generalize to all conceivability judgments concerningphenomenal states. Consequently, one could defend absolutely any theoryof phenomenal states against conceivability arguments in just this way.This result conflicts with too many of our common sense beliefs aboutthe evidential value of conceivability with respect to phenomenalstates. The general moral is that the application of such principles ofexplanatory defeat is neither simple nor straightforward.
Bilinear Entropy Expansion from the Decisional Linear Assumption

We develop a technique inspired by pseudorandom functions that allows us to increase the entropy available for proving the security of dual system encryption schemes under the Decisional Linear Assumption. We show an application of the tool to Attribute-Based Encryption by presenting a Key-Policy ABE scheme that is fully-secure under DLIN with short public parameters.
A two-fluid study of oblique tearing modes in a force-free current sheet

Kinetic simulations have demonstrated that three-dimensional reconnection in collisionless regimes proceeds through the formation and interaction of magnetic flux ropes, which are generated due to the growth of tearing instabilities at multiple resonance surfaces. Since kinetic simulations are intrinsically expensive, it is desirable to explore the feasibility of reduced two-fluid models to capture this complex evolution, particularly, in the strong guide field regime, where two-fluid models are better justified. With this goal in mind, this paper compares the evolution of the collisionless tearing instability in a force-free current sheet with a two-fluid model and fully kinetic simulations. Our results indicate that the most unstable modes are oblique for guide fields larger than the reconnecting field, in agreement with the kinetic results. The standard two-fluid tearing theory is extended to address the tearing instability at oblique angles. The resulting theory yields a flat oblique spectrum and underestimates the growth of oblique modes in a similar manner to kinetic theory relative to kinetic simulations.
Parametric down-conversion photon pair source on a nanophotonic chip

Quantum-photonic chips, which integrate quantum light sources alongside active and passive optical elements, as well as single-photon detectors, show great potential for photonic quantum information processing and quantum technology. Mature semiconductor nanofabrication processes allow for scaling such photonic integrated circuits to on-chip networks of increasing complexity. Second-order nonlinear materials are the method of choice for generating photonic quantum states in the overwhelming majority of linear optic experiments using bulk components, but integration with waveguide circuitry on a nanophotonic chip proved to be challenging. Here, we demonstrate such an on-chip parametric down-conversion source of photon pairs based on second-order nonlinearity in an aluminum-nitride microring resonator. We show the potential of our source for quantum information processing by measuring the high visibility anti-bunching of heralded single photons with nearly ideal state purity. Our down-conversion source yields measured coincidence rates of 80 Hz, which implies MHz generation rates of correlated photon pairs. Low noise performance is demonstrated by measuring high coincidence-to-accidental ratios. The generated photon pairs are spectrally far separated from the pump field, providing great potential for realizing sufficient on-chip filtering and monolithic integration of quantum light sources, waveguide circuits and single-photon detectors. A chip-based source of photon pairs for applications in quantum information processing has been built by a team of scientists in the US. Xiang Guo and co-workers from Yale University built the quantum light source from an aluminum nitride microring resonator. The strong second-order nonlinearity of the aluminum nitride yields efficient parametric down-conversion. This allows 775-nm-wavelength pump photons to be converted into a pair of entangled photons in the telecommunications window of 1550 nm. Tests indicated that the heralded photons generated by the microring source are anti-bunched and have high visibility and a high purity of state, indicating that they are highly suitable for use in quantum optics experiments. In principle, the on-chip source is compatible with megahertz generation rates and large-scale manufacture of integrated optical circuits.
Conditions on Consistency of Probabilistic Tree Adjoining Grammars

Much of the power of probabilistic methods in modelling language comes from their ability to compare several derivations for the same string in the language. An important starting point for the study of such cross-derivational properties is the notion of consistency. The probability model defined by a probabilistic grammar is said to be consistent if the probabilities assigned to all the strings in the language sum to one. From the literature on probabilistic context-free grammars (CFGs), we know precisely the conditions which ensure that consistency is true for a given CFG. This paper derives the conditions under which a given probabilistic Tree Adjoining Grammar (TAG) can be shown to be consistent. It gives a simple algorithm for checking consistency and gives the formal justification for its correctness. The conditions derived here can be used to ensure that probability models that use TAGs can be checked for deficiency (i.e. whether any probability mass is assigned to strings that cannot be generated).
The Effect of Race and Gender on Bail Outcomes: A Test of an Interactive Model

This paper responds to suggestions that researchers interested in the relationship between defendant race, defendant gender, and criminal justice outcomes broaden their focus to include pretrial decision making. We used data on defendants charged with violent felonies in Detroit Recorder’s Court to analyze the effect of race and gender on the amount of bail imposed by the judge and on the defendant’s pretrial status. We found that judges take gender, but not race, into account in determining the amount of bail for certain types of cases; more specifically, Black females faced lower bail than Black males in less serious cases. In contrast, we found that both race and gender affected the likelihood of pretrial release. White defendants were more likely than black defendants to be released pending trial and females were more likely than males to be released prior to trial. In fact, white females, white males, and black females all were more likely than black males to be released.
EFFECTS OF ANTENNA BEAM CHROMATICITY ON REDSHIFTED 21 cm POWER SPECTRUM AND IMPLICATIONS FOR HYDROGEN EPOCH OF REIONIZATION ARRAY

Author(s): Thyagarajan, Nithyanandan; Parsons, Aaron R; DeBoer, David R; Bowman, Judd D; Ewall-Wice, Aaron M; Neben, Abraham R; Patra, Nipanjana
A General Strategy for Organocatalytic Activation of C–H Bonds via Photoredox Catalysis: Direct Arylation of Benzylic Ethers

Direct C–H functionalization and arylation of benzyl ethers has been accomplished via photoredox organocatalysis. The productive merger of a thiol catalyst and a commercially available iridium photoredox catalyst in the presence of household light directly affords benzylic arylation products in good to excellent yield. The utility of this methodology is further demonstrated in direct arylation of 2,5-dihydrofuran to form a single regioisomer.
Enantioselective photoredox catalysis enabled by proton-coupled electron transfer: development of an asymmetric aza-pinacol cyclization.

The first highly enantioselective catalytic protocol for the reductive coupling of ketones and hydrazones is reported. These reactions proceed through neutral ketyl radical intermediates generated via a concerted proton-coupled electron transfer (PCET) event jointly mediated by a chiral phosphoric acid catalyst and the photoredox catalyst Ir(ppy)2(dtbpy)PF6. Remarkably, these neutral ketyl radicals appear to remain H-bonded to the chiral conjugate base of the Bronsted acid during the course of a subsequent C–C bond-forming step, furnishing syn 1,2-amino alcohol derivatives with excellent levels of diastereo- and enantioselectivity. This work provides the first demonstration of the feasibility and potential benefits of concerted PCET activation in asymmetric catalysis.
Dynamics of Lipids, Cholesterol, and Transmembrane α-Helices from Microsecond Molecular Dynamics Simulations

Extensive all-atom molecular dynamics (∼24 μs total) allowed exploration of configurational space and calculation of lateral diffusion coefficients of the components of a protein-embedded, cholesterol-containing model bilayer. The three model membranes are composed of an ∼50/50 (by mole) dipalmitoylphosphatidylcholine (DPPC)/cholesterol bilayer and contained an α-helical transmembrane protein (HIV-1 gp41 TM). Despite the high concentration of cholesterol, normal Brownian motion was observed and the calculated diffusion coefficients (on the order of 10–9 cm2/s) are consistent with experiments. Diffusion is sensitive to a variety of parameters, and a temperature difference of ∼4 K from thermostat artifacts resulted in 2–10-fold differences in diffusion coefficients and significant differences in lipid order, membrane thickness, and unit cell area. Also, the specific peptide sequence likely underlies the consistently observed faster diffusion in one leaflet. Although the simulations here present molecular dy...
Modeling Ultimate Loss Given Default on Corporate Debt

Loss given default (LGD) is a critical parameter in various facets of credit risk modeling. This study empirically investigates the determinants of LGD and builds alternative predictive econometric models for LGD on bonds and loans using an extensive sample of most major U.S. defaults in the 1985–2008 period. The authors build simultaneous equation models in the beta-link generalized linear model (BLGLM) class, identifying several that perform well in terms of the quality of estimated parameters as well as overall model performance metrics. This extends prior work by modeling LGD both at the firm and the instrument levels. In a departure from the extant literature, the authors find the economic and statistical significance of firm-specific debt and equity market variables. In particular, they find that information from either the equity or the debt markets at around the time of default (measures of either cumulative equity returns or distressed debt prices, respectively) have predictive power with respect to the ultimate LGD, which is in line with recent prior recovery and asset pricing research. They also document a new finding: Larger firms have significantly lower LGDs while larger loans have higher LGDs.
C iv and He ii line emission of Lyman α blobs: powered by shock-heated gas

Utilizing {\it ab initio} ultra-high resolution hydrodynamical simulations, we investigate the properties of the interstellar and circum-galactic medium of Ly$\alpha$ Blobs (LABs) at $z=3$, focusing on three important emission lines: Ly$\alpha$ 1216\AA, \heii 1640\AA\ and \civ 1449\AA. Their relative strengths provide a powerful probe of the thermodynamic properties of the gas when confronted with observations. By adjusting the dust attenuation effect using one parameter and matching the observed size-luminosity relation of LABs using another parameter, we show that our simulations can reproduce the observed \civ/\lya\ and \heii/\lya\ ratios adequately. This analysis provides the first successful physical model to account for simultaneously the LAB luminosity function, luminosity-size relation, and the \civ/Ly$\alpha$ and \heii/Ly$\alpha$ ratios, with only two parameters. The physical underpinning for this model is that, in addition to the stellar component for the \lya\ emission, the \lya\ and \civ\ emission lines due to shock heated gas are primarily collisional excitation driven and the \heii\ emission line collisional ionization driven. We find that the density, temperature and metallicity of the gas responsible for each emission line is significantly distinct, in a multi-phase interstellar and circumgalactic medium that is shock-heated primarily by supernovae and secondarily by gravitational accretion of gas.
Phosphate-Sulfate Interaction in Simulated Low-level Radioactive Waste Glasses

Using simulated low-level radioactive waste glasses, interaction between phosphate and sulfate in the glass network was systematically studied using Raman spectroscopy. Phosphate and sulfate interaction was shown to depend on the extent of saturation of both species in the glass. At elevated concentration level of phosphate and sulfate in combination, yet below the solubility limits, phosphate and sulfate both separated from the glass. In the 7-day product consistency test (PCT), the phase separated glasses were found to have higher normalized releases of sodium, phosphorous, sulfur, boron, and silicon than those of their baseline glasses without phase separation.
Visible-light photocatalyzed cross-linking of diacetylene ligands by quantum dots to improve their aqueous colloidal stability.

Ligand cross-linking is known to improve the colloidal stability of nanoparticles, particularly in aqueous solutions. However, most cross-linking is performed chemically, in which it is difficult to limit interparticle cross-linking, unless performed at low concentrations. Photochemical cross-linking is a promising approach but usually requires ultraviolet (UV) light to initiate. Using such high-energy photons can be harmful to systems in which the ligand–nanoparticle bond is fairly weak, as is the case for the commonly used semiconductor quantum dots (QDs). Here, we introduce a novel approach to cross-link thiolated ligands on QDs by utilizing the photocatalytic activity of QDs upon absorbing visible light. We show that using visible light leads to better ligand cross-linking by avoiding the problem of ligand dissociation that occurs upon UV light exposure. Once cross-linked, the ligands significantly enhance the colloidal stability of those same QDs that facilitated cross-linking.
UV resonance Raman investigation of the aqueous solvation dependence of primary amide vibrations.

We investigated the normal mode composition and the aqueous solvation dependence of the primary amide vibrations of propanamide. Infrared, normal Raman, and UV resonance Raman (UVRR) spectroscopy were applied in conjunction with density functional theory (DFT) to assign the vibrations of crystalline propanamide. We examined the aqueous solvation dependence of the primary amide UVRR bands by measuring spectra in different acetonitrile/water mixtures. As previously observed in the UVRR spectra of N-methylacetamide, all of the resonance enhanced primary amide bands, except for the Amide I (AmI), show increased UVRR cross sections as the solvent becomes water-rich. These spectral trends are rationalized by a model wherein the hydrogen bonding and the high dielectric constant of water stabilizes the ground state dipolar –O—C═NH2+ resonance structure over the neutral O═C—NH2 resonance structure. Thus, vibrations with large C—N stretching show increased UVRR cross sections because the C—N displacement between th...
Fluorescent DNA base replacements: Reporters and sensors for biological systems.

We describe the design, synthesis, and properties of nucleoside monomers in which the DNA base is replaced by fluorescent hydrocarbons and heterocycles, and the assembly of these monomers into DNA-like molecules in which the all bases are fluorescent. As monomers, such molecules have useful applications as reporters in the DNA context. The use of fluorescent DNA bases, rather than more traditional fluorophores tethered to the DNA strand, gives a more predictable location and orientation, and yields a more direct response to changes that occur within the helix. In addition to uses as monomers, such compounds can be assembled into polychromophoric oligomers (“oligodeoxyfluorosides” or ODFs). ODFs are water soluble, discrete molecules and are easily arranged into specific sequences by use of a DNA synthesizer. They have displayed a number of properties not readily available in commercial fluorophores, including large Stokes shifts, tunable excitation and emission wavelengths, and sensing responses to physical changes or molecular species in solution. We describe an approach to assembling and screening large sets of oligofluorosides for rapid identification of molecules with desirable properties. Such compounds show promise for applications in biochemistry, biology, environmental and materials applications.
The Balance of Power in International History Theory and Reality

Many observers have recently noted that the international system is evolving into a multipolar world. At the same time, the notion of balance of power is being severely criticized for its vagueness...
Metal-Free Trifluoromethylation of Aromatic and Heteroaromatic Aldehydes and Ketones

The ability to convert simple and common substrates into fluoroalkyl derivatives under mild conditions remains an important goal for medicinal and agricultural chemists. One representative example of a desirable transformation involves the conversion of aromatic and heteroaromatic ketones and aldehydes into aryl and heteroaryl β,β,β-trifluoroethylarenes and -heteroarenes. The traditional approach for this net transformation involves stoichiometric metals and/or multistep reaction sequences that consume excessive time, material, and labor resources while providing low yields of products. To complement these traditional strategies, we report a one-pot metal-free decarboxylative procedure for accessing β,β,β-trifluoroethylarenes and -heteroarenes from readily available ketones and aldehydes. This method features several benefits, including ease of operation, readily available reagents, mild reaction conditions, high functional-group compatibility, and scalability.
Evolutionary dynamics of extremal optimization

Dynamic features of the recently introduced extremal optimization heuristic are analyzed. Numerical studies of this evolutionary search heuristic show that it performs optimally at a transition between a jammed and an diffusive state. Using a simple, annealed model, some of the key features of extremal optimization are explained. In particular, it is verified that the dynamics of local search possesses a generic critical point under the variation of its sole parameter, separating phases of too greedy (non-ergodic, jammed) and too random (ergodic, diffusive) exploration. Analytic comparison with other local search methods, such as a fixed temperature Metropolis algorithm, within this model suggests that the existence of the critical point is the essential distinction leading to the optimal performance of the extremal optimization heuristic.
Pediatric Residents' Attitudes and Practices Regarding Tobacco Cessation Counseling

To assess the current status of pediatric residency training in counseling and referring on tobacco use and smoke exposure An anonymous voluntary nationwide survey of all pediatric and med peds residents in the United States was conducted from May 2014 to November 2014 via use of Qualtrics.com. The questionnaire survey assessed the …
A prototype simulation-based optimization approach to model feedstock development for chemical process industry

Abstract Incorporating non-traditional feedstocks, e.g., biomass, to chemical process industry (CPI) will require investments in research & development (R&D) and capacity expansions. The impact of these investments on the evolution of biomass to commodity chemicals (BTCC) system should be studied to ensure a cost-effective transition with acceptable risk levels. The BTCC system includes both exogenous, e.g., product demands (decision-independent) and endogenous, e.g., the change in technology cost with investment levels (decision-dependent) uncertainties. This paper presents a prototype simulation-based optimization (SIMOPT) approach to study the BTCC system evolution under exogenous and endogenous uncertainties, and provides a preliminary analysis of the impact of using three different sampling methods, i.e., Monte Carlo, Latin Hypercube, and Halton sequence, to generate the simulation runs on the computational cost of the SIMOPT approach. The results of a simplified case study suggest that annual demand increases is the dominant factor for the total cost of the BTCC system. The results also suggest that using Halton sequence as the sampling method yields the smallest number of samples, i.e., the least computational cost, to achieve a statistically significant solution.
Identifying and tracking simulated synaptic inputs from neuronal firing: insights from in vitro experiments

Accurately describing synaptic interactions between neurons and how interactions change over time are key challenges for systems neuroscience. Although intracellular electrophysiology is a powerful tool for studying synaptic integration and plasticity, it is limited by the small number of neurons that can be recorded simultaneously in vitro and by the technical difficulty of intracellular recording in vivo. One way around these difficulties may be to use large-scale extracellular recording of spike trains and apply statistical methods to model and infer functional connections between neurons. These techniques have the potential to reveal large-scale connectivity structure based on the spike timing alone. However, the interpretation of functional connectivity is often approximate, since only a small fraction of presynaptic inputs are typically observed. Here we use in vitro current injection in layer 2/3 pyramidal neurons to validate methods for inferring functional connectivity in a setting where input to the neuron is controlled. In experiments with partially-defined input we inject a single simulated input with known amplitude on a background of fluctuating noise. In a fully-defined input paradigm we then control the synaptic weights and timing of many (1024) simulated presynaptic neurons. By analyzing the firing of neurons in response to these artificial inputs, we ask 1) How does functional connectivity inferred from spikes relate to simulated synaptic input? and 2) What are the limitations of connectivity inference? Using likelihood-based models of functional connectivity, we find that individual current-based synaptic inputs are detectable over a broad range of amplitudes and conditions. Detectability depends on input amplitude and output firing rate, and excitatory inputs are detected more readily than inhibitory (Figure ​(Figure1).1). Moreover, as we model increasing numbers of presynaptic inputs, we are able to estimate connection strengths more accurately and detect the presence of connections more quickly. We find that model-based methods outperform previous methods for detecting synaptic connections (nonparametric tests on the cross-correlation), and simulation results (adaptive exponential integrate-and-fire) suggest that the model results hold even when synaptic input is conductance-based rather than current-based. Together these results illustrate the possibilities and outline the limits of inferring synaptic input from spikes. Figure 1 A) Detectability of synaptic inputs of different strengths in a fully-defined input paradigm (data for N = 4 Layer 2/3 pyramidal cells) for 1Hz, 5Hz, and 10Hz post-synaptic firing rates. Note that detection of inputs improves with higher firing rates ...
Cross Validation Bandwidth Selection for Derivatives of Multidimensional Densities

Investigates the extension of cross validation methods to higher dimensions for the derivative of an unconditional joint density.
Bitline PUF: Building Native Challenge-Response PUF Capability into Any SRAM

Physical Unclonable Functions PUFs are specialized circuits with applications including key generation and challenge-response authentication. PUF properties such as low cost and resistance to invasive attacks make PUFs well-suited to embedded devices. Yet, given how infrequently the specialized capabilities of a PUF may be needed, the silicon area dedicated to it is largely idle. This inefficient resource usage is at odds with the cost minimization objective of embedded devices. Motivated by this inefficiency, we propose the Bitline PUF --- a novel PUF that uses modified wordline drivers together with SRAM circuitry to enable challenge-response authentication. The number of challenges that can be applied to the Bitline PUF grows exponentially with the number of SRAM rows, and these challenges can be applied at any time without power cycling. This paper presents in detail the workings of the Bitline PUF, and shows that it achieves high throughput, low latency, and uniqueness across instances. Circuit simulations indicate that the Bitline PUF responses have a nominal bit-error-rate BER of 0.023 at 1.2i??V supply and 27i??C, and that BER does not exceed 0.076 when supply voltage is varied from 1.1i??V to 1.3i??V, or when temperature is varied from 0i??C to 80i??C. Because the Bitline PUF leverages existing SRAM circuitry, its area overhead is only a single flip-flop and two logic gates per row of SRAM. The combination of high performance and low cost makes the Bitline PUF a promising candidate for commercial adoption and future research.
The influence of urinary macromolecules on calcium oxalate monohydrate crystal growth.

Abstract The Constant Composition (CC) kinetics method has been used for studying the mineralization of calcium oxalate monohydrate (COM) at sustained supersaturations in the presence of pre-bladder urine and macromolecules isolated from normal urine and kidney and bladder stones. The method is especially sensitive for investigating the inhibitory activities of these urinary macromolecular components (UMMC) and matrix macromolecular components (MMMC) with a coefficient of variation in growth rate of ~2%. Significant COM mineral inhibition was observed in a wide molecular weight region of urine components. Urine removed directly from the kidney showed appreciable inhibitory activity towards COM crystallization. Normal urinary proteins and the dissolved precipitate resulting from urine centrifugation were fractionated by gel filtration. The resulting solutions were mostly COM mineralization inhibitors. Electrodialysis was utilized to isolate the MMMC (>7000 d) of renal and bladder calculi. While these solutions inhibited COM crystallization, they were also found to be calcium binders as measured by the calcium electrode.
Does pre-employment drug use predict on-the-job suitability?

Drug testing is increasingly used in the screening of applicants for employment. Despite the growth of drug testing, there is little research that examines the value of pre-employment drug-use information in the prediction of post-employment suitability. This research, which was based on a sample of 10,i88 young adults, examined the criterion-related validity of pre-employment drug-use information. For all drugs examined, the greater the frequency of use and the earlier the age at which the drug was first used, the greater the probability of a person being classified as unsuitable after hire. However, the operational validity of each drug variable was influenced by the base rate of drug use. The low base rates for some drugs make their operational validity of limited value. The operational validity of the marijuana frequency-of-use measure (.07) was approximately equal to that of less frequently used drugs (e.g., stimulants and depressants). No strong moderators of the validity of a drug-composite measure were found.
The effect of routine breast examination on serum prolactin levels

Objective To evaluate the effect of a routine breast examination on serum PRL levels. Design Prospective clinical study. Setting University-based reproductive endocrinology unit. Patients Eleven nonlactating, euprolactinemic women of reproductive age with a history of regular menstrual cycles and currently taking no medications. Interventions Breast examination using standard technique. Main Outcome Measure Changes in serum PRL levels after breast examination. Results Baseline PRL levels ranged from 3.64 to 19.23 ng/mL (mean 7.17 ng/mL; conversion factor to SI unit, 1.00). There were no significant increases in PRL levels after breast examination, with mean PRL levels after 15, 30, and 45 minutes of 6.59, 6.84, and 6.45 ng/mL, respectively. Conclusion Routine breast examination does not alter acutely serum PRL levels in normal women.
Distributed entertainment environment

The development of interactive computer games can be traced back to about 1960, with the development of Spacewar at MIT. However, it was not until 1972 that computer gaming penetrated the mass market, in the shape of Pong. Developed by Nolan Bushnell, founder of the first videogame company (Atari, 1968), it was an overnight sensation. Throughout the 1970s Atari continued to develop and release arcade-based gaming systems, and in 1976 it took videogames into consumers’ homes, with the VCS 2600. Since that time, although the technology has drastically improved with the standard PC now a major player in the games market, the fundamental style of gaming has not changed.
Twelve-channel strained-layer InGaAs–GaAs–AlGaAs buried heterostructure quantum well laser array for WDM applications by selective-area MOCVD

Selective-area epitaxy is used to fabricate a twelve-channel strained layer InGaAs-GaAs-AlGaAs buried heterostructure quantum well laser array suitable for wavelength division multiplexing applications. The measured wavelength separation between elements is 1.9 nm, in good agreement with the 2 nm design value. >
Feature Selection for Ranking of Most Influential Variables for Evacuation Behavior Modeling Across Disasters

The extensive list of factors that affect the evacuee decision process makes it difficult to design effective surveys and to develop decision models with high predictive power. Regression models and significance levels can help identify relevant variables and overcome this problem to an extent. However, such approaches fall short of ranking these variables or recognizing the redundant ones. In this study, the use of a feature selection method was proposed to ensure that the selected features were relevant and not at the same time redundant. This method, called conditional mutual information maximization, consists of picking features at each step and minimizes the uncertainty in the decision conditional on the response of any feature already picked. As a case study, the variables influencing evacuation behavior in the Northern New Jersey Evacuation Survey were ranked and compared for disaster scenarios. To validate the method and to demonstrate how it compared with the traditional methods, logistic regress...
A Family Planning Unit for Your Hospital

For the administrator and the physician, a hospital-based family planning service offers the opportunity to respond to a pressing community need at a relatively low expenditure of both time and funds. In hospitals that have already established such clinics, Dr. Perkin points out, a steady rise in enrollment is accompanied by a decline both in deliveries and in admissions for induced abortion.
Intramolecular Conjugate Additions with Heterocyclic Olefins.

The intramolecular reactions of olefinic N-heterocycles have been studied. In triflic acid-promoted reactions, conjugate addition is observed with pyrazine-, 2-pyrimidine-, and 2-quinoxaline-based olefins and a phenyl group nucleophile. Markovnikov addition is observed with pyridine and 5-quinoxaline-based olefins. These results are in accordance with previous observations relating the type of addition—conjugate or Markovnikov—to the positions of olefinic substituents of the N-heterocycle.
A Simple and Versatile Amide Directing Group for C-H Functionalizations.

Achieving selective C−H activation at a single and strategic site in the presence of multiple C−H bonds can provide a powerful and generally useful retrosynthetic disconnection. In this context, a directing group serves as a compass to guide the transition metal to C−H bonds by using distance and geometry as powerful recognition parameters to distinguish between proximal and distal C−H bonds. However, the installation and removal of directing groups is a practical drawback. To improve the utility of this approach, one can seek solutions in three directions: 1) Simplifying the directing group, 2) using common functional groups or protecting groups as directing groups, and 3) attaching the directing group to substrates via a transient covalent bond to render the directing group catalytic. This Review describes the rational development of an extremely simple and yet broadly applicable directing group for PdII, RhIII, and RuII catalysts, namely the N-methoxy amide (CONHOMe) moiety. Through collective efforts in the community, a wide range of C−H activation transformations using this type of simple directing group have been developed.