cssi/SciSciGPT-SciSciNet huggingface dataset:
Carbon Nanotubes: Synthesis, Integration, and Properties

Synthesis of carbon nanotubes by chemical vapor deposition over patterned catalyst arrays leads to nanotubes grown from specific sites on surfaces. The growth directions of the nanotubes can be controlled by van der Waals self-assembly forces and applied electric fields. The patterned growth approach is feasible with discrete catalytic nanoparticles and scalable on large wafers for massive arrays of novel nanowires. Controlled synthesis of nanotubes opens up exciting opportunities in nanoscience and nanotechnology, including electrical, mechanical, and electromechanical properties and devices, chemical functionalization, surface chemistry and photochemistry, molecular sensors, and interfacing with soft biological systems.
Advanced Light Source (ALS) beam position monitor

The requirements, design, and performance of the ALS BPM (beam position monitor) system are discussed. Considerable effort has gone into the storage-ring BPM system design because very fast and accurate measurements are needed. The speed and accuracy requirements in the electronics are met with parallel processing and error-correction techniques. A tuned receiver is provided for every beam position pickup, and for every array of four pickups there is a microprocessor controlling the measurement and recording data. To be useful during storage-ring commissioning, injection studies, and at other times when instant response is required, the BPM system must respond to a single turn of beam and also be able to store data from many turns. This is especially important with a low injection rate. The required bandwidth in this case is about 2 MHz. Accuracy and resolution of 0.5 mm are adequate for these high-speed measurements. >
Shape‐Controlled Synthesis of Metal Nanostructures: The Case of Palladium

This article features shape-controlled synthesis of Pd nanostructures. Similar to the Ag system, both the crystallinity of seeds and the growth rates of different crystallographic facets play a vital role in determining the final shape of a resultant nanostructure. We specifically discuss how the reduction rate can be controlled to maneuver the crystallinity (i.e., single-crystal, single twinned, and multiple twinned) of seeds in the nucleation stage. The distribution of multiple twinned and single-crystal seeds can be further manipulated by employing oxidative etching. As the seed grows into a nanocrystal, the growth rates of different facets (e.g., {111} versus {100}) can be altered with capping agents to control the final shape. The ability to generate Pd nanostructures with a variety of geometrical shapes provides a great opportunity to systematically evaluate their electrical, plasmonic, and catalytic properties, as well as to fully explore their applications.
The Convex Geometry of Linear Inverse Problems

In applications throughout science and engineering one is often faced with the challenge of solving an ill-posed inverse problem, where the number of available measurements is smaller than the dimension of the model to be estimated. However in many practical situations of interest, models are constrained structurally so that they only have a few degrees of freedom relative to their ambient dimension. This paper provides a general framework to convert notions of simplicity into convex penalty functions, resulting in convex optimization solutions to linear, underdetermined inverse problems. The class of simple models considered includes those formed as the sum of a few atoms from some (possibly infinite) elementary atomic set; examples include well-studied cases from many technical fields such as sparse vectors (signal processing, statistics) and low-rank matrices (control, statistics), as well as several others including sums of a few permutation matrices (ranked elections, multiobject tracking), low-rank tensors (computer vision, neuroscience), orthogonal matrices (machine learning), and atomic measures (system identification). The convex programming formulation is based on minimizing the norm induced by the convex hull of the atomic set; this norm is referred to as the atomic norm. The facial structure of the atomic norm ball carries a number of favorable properties that are useful for recovering simple models, and an analysis of the underlying convex geometry provides sharp estimates of the number of generic measurements required for exact and robust recovery of models from partial information. These estimates are based on computing the Gaussian widths of tangent cones to the atomic norm ball. When the atomic set has algebraic structure the resulting optimization problems can be solved or approximated via semidefinite programming. The quality of these approximations affects the number of measurements required for recovery, and this tradeoff is characterized via some examples. Thus this work extends the catalog of simple models (beyond sparse vectors and low-rank matrices) that can be recovered from limited linear information via tractable convex programming.
An Interactive Domain Independent Approach to Robust Dialogue Interpretation

We discuss an interactive approach to robust interpretation in a large scale speech-to-speech translation system. Where other interactive approaches to robust interpretation have depended upon domain dependent repair rules, the approach described here operates efficiently without any such hand-coded repair knowledge and yields a 37% reduction in error rate over a corpus of noisy sentences.
On communication over an entanglement-assisted quantum channel

Shared entanglement is a resource available to parties communicating over a quantum channel, much akin to public coins in classical communication protocols: the two parties may be given some number of quantum bits jointly prepared in a fixed superposition, prior to communicating with each other. The quantum channel is then said to be "entanglement-assisted." Shared randomness does not help in the transmission of information from one party to another. Moreover, it does not significantly reduce the classical complexity of computing functions vis-a-vis private-coin protocols. On the other hand, prior entanglement leads to startling phenomena such as "quantum teleportation" and "superdense coding." The problem of characterising the power of prior entanglement has baffled many researchers, especially in the setting of bounded-error protocols. It is open whether it leads to more than a factor of two savings (using superdense coding) or more than an additive O(log) savings (when used to create shared randomness). Few lower bounds are known for communication problems in this setting, and are all derived using sophisticated information theoretic techniques. In this paper, we focus on the most basic problem in the setting of communication over an entanglement-assisted quantum channel, that of communicating classical bits from one party to another. We derive optimal bounds on the number of quantum bits required for this task, for any given probability of error.
Modeling Viscous Transonic Limit Cycle Oscillation Behavior Using a Harmonic Balance Approach

Presented is a harmonic-balance computational fluid dynamic approach for modeling limit-cycle oscillation behavior of aeroelastic airfoil configurations in a viscous transonic flow. For the NLR 7301 airfoil configuration studied, accounting for viscous effects is shown to significantly influence computed limit-cycle oscillation trends when compared to an inviscid analysis. A methodology for accounting for changes in mean angle of attack during limit-cycle oscillation is also developed.
How Do Workers Fare During Transition? Perceptions of Job Insecurity among Russian Workers, 1995-2004

Abstract Labor market conditions deteriorated substantially in the1990s during Russia's transition from plan to market, generating pervasive and prolonged economic insecurity. Our objective is to document perceptions of job insecurity among Russian workers over the course of the transition period and evaluate whether these perceptions are consistent with actual economic outcomes. We use RLMS data to examine perceptions of job insecurity among Russian workers between 1995 and 1998, when economic conditions were relatively chaotic, and between 2000 and 2004, when economic conditions had stabilized. We employ two measures to assess worker perceptions of job insecurity: one reflects workers' concerns about job loss, and the second evaluates their concern about ability to find employment in case of a lay-off. Our descriptive analysis focuses on workers who perceived their job situation as insecure during this period, categorizing workers based on their socio-demographic characteristics, job characteristics and region of residence. Using ordered probit analysis, we study conditional distributions of our measures of perceived job insecurity, and how those varied by worker characteristics, current economic conditions, and over time. Similar to studies conducted in developed market economies, we find that perceptions of job security are higher among workers with more education, among workers with status positions (supervisory responsibilities), and among workers who live in locales that are not adversely affected by economic conditions. Unlike these studies, however, we find that perceptions differ between men and women; age is negatively, rather than positively, correlated with confidence in keeping one's current job; and longer job tenure does not improve perceptions of job security. We find that worker perceptions are largely consistent with actual labor market conditions. Specifically, perceptions of job security were very low in years of major economic change and uncertainty (1995–1998), but improved during the years of relative economic stability (2000–2004). In both periods, workers with relatively weak positions in the labor market tended to have lower perceptions of job insecurity.
An Efficient Synthesis of (−)-Chloramphenicol via Asymmetric Catalytic Aziridination: A Comparison of Catalysts Prepared from Triphenylborate and Various Linear and Vaulted Biaryls

[reaction--see text] The antibiotic (-)-choramphenicol has been synthesized in only four steps from p-nitro-benzaldehyde in optically pure form from an asymmetric catalytic aziridination reaction with a chiral catalyst prepared from triphenylborate and the (R)-VAPOL ligand. Catalysts generated from the VAPOL and VANOL ligands give much higher asymmetric induction than do catalysts prepared from 6,6'-diphenylVAPOL, BINOL, and BANOL ligands.
Prophet Inequalities for I.I.D. Random Variables with Random Arrival Times

Abstract Suppose X 1, X 2,… are independent and identically distributed nonnegative random variables with finite expectation, and for each k, X k is observed at the kth arrival time S k of a Poisson process with a unit rate independent of the sequence {X k }. For t > 0, comparisons are made between the expected maximum M(t) := E[max k≥1 X k I(S k ≤ t)] and the optimal stopping value V(t) := supτ∊E[X τ I(S τ ≤ t)], where  is the set of all ℕ-valued random variables τ such that {τ = i} is measurable with respect to the σ-algebra generated by (X 1, S 1),…, (X i , S i ). For instance, it is shown that M(t)/V(t) ≤ 1 + α0, where α0 ≐ 0.34149 satisfies , and this bound is asymptotically sharp as t → ∞. Another result is that M(t)/V(t) < 2 − (1 − e −t )/t, and this bound is asymptotically sharp as t ↓ 0. Upper bounds for the difference M(t) − V(t) are also given, under the additional assumption that the X k 's are bounded.
Simulation of energy sharing among flywheels in parallel configuration

Flywheel express pallet experiment (FEPE) has been proposed on the international space station to study flywheel energy storage application for space power systems. In support of that effort, simulation of two independent, coaxially rotating flywheels, supplied from a common DC bus, was performed. The simulation procedure was divided into three simple steps. First, both flywheels are charged approximately to half way of the speed range. Then, charging of one flywheel is continued to fully charged state while discharging the other to minimum charge state. Finally, charge/discharge process is reversed to switch the energy storage states of the two flywheels. System description, scope of simulation, discussion of simulation results, and conclusions will be presented.
Dynamic heterogeneities versus fixed heterogeneities in earthquake models

SUMMARY A debate has raged over whether fixed material and geometrical heterogeneities, or alternatively dynamic stress heterogeneities, arising through frictional instabilities dominate earthquake complexity. It may also be that both types of heterogeneities interact and are important. This paper makes a first step in examining this interaction, combining two previously separate lines of research. One line examined friction, which has attractors (the subset of the phase space that the system evolves towards in the long run) on homogeneous faults, which are simple, and then added fixed heterogeneities to the faults to obtain complex attractors. Another line examined frictions, which produced complex attractors on homogeneous faults. Here, we examine frictions, which produce complex attractors on homogeneous faults, and study them on heterogeneous faults, in order to study the interaction of dynamic stress heterogeneities and fixed fault heterogeneities. We consider two types of fixed heterogeneities: an additive noise and a multiplicative noise to the frictional strength of the fault. Because of the linearity of the bulk elastodynamics, the attractor is unaffected by additive fixed noise in the strength of the fault: adding an arbitrary function of space, fixed in time, to the friction leaves the resulting attractor unchanged. In contrast, multiplicative fixed noise multiplying the friction can have a profound effect on the resulting attractor. In the small multiplicative noise amplitude limit, the frictional weakening attractor is little perturbed; at finite amplitudes, fixed heterogeneities substantially alter the attractor. We see, as one consequence, a shift toward longer length events at larger amplitudes. Fixed heterogeneities are seen to reduce the irregularities created by the frictional instability we study, but by no means destroy them. We quantify this by examining a measure of variability of the importance in hazard estimates, the coefficient of variation of large event recurrence times. The coefficient of variation is seen to remain substantial even for large fixed heterogeneities. For friction that weakens with time, so the underlying uniform fault attractor is simple, fixed heterogeneities increase irregularity. For all frictions examined, at low fixed heterogeneity the stress concentrations left over by the ends of the large events dominate where most of the small events occur, while at higher heterogeneity the stress irregularities left over by fixed fault heterogeneities begin to dominate where the small events occur. This may be the strongest signature of fixed heterogeneities, and should be examined further in the Earth. Finally, in what may have important implications for more sophisticated estimates of earthquake hazard, we see a correlation of locations with lower strength drop having higher variation in large event repeat times.
Nondeterministic circuit lower bounds from mildly derandomizing Arthur-Merlin games

In several settings, derandomization is known to follow from circuit lower bounds that themselves are equivalent to the existence of pseudorandom generators. This leaves open the question whether derandomization implies the circuit lower bounds that are known to imply it, i.e., whether the ability to derandomize in any way implies the ability to do so in the canonical way through pseudorandom generators. For the setting of decision problems, Impagliazzo, Kabanets, and Wigderson (2002) implicitly showed the following equivalence: Randomized polynomial-time decision procedures for promise problems can be simulated in $${\sf{NSUBEXP}}$$NSUBEXP (the subexponential version of $${\sf{NP}}$$NP) with subpolynomial advice on infinitely many input lengths if and only if$${{\sf{NEXP}} \not \subseteq }$$NEXPź$${\sf{P}/ poly}$$P/poly. We establish a full analog in the setting of verification procedures: Arthur-Merlin games for promise problems can be simulated in $${{\sf{\Sigma_{2} SUBEXP}}}$$Σ2SUBEXP (the subexponential version of $${\sf{\Sigma_{2} P}}$$Σ2P) with subpolynomial advice on infinitely many input lengths if and only if$${\sf{\Sigma_2EXP} \not \subseteq }$$Σ2EXPź$${\sf{NP}/poly}$$NP/poly. A key ingredient in our proofs is improved Karp-Lipton style collapse results for nondeterministic circuits. The following are two instantiations that may be of independent interest: Assuming that Arthur-Merlin games can be derandomized in $${{\sf{\Sigma_{2}} P}}$$Σ2P, we show that (i) $${\sf{PSPACE} \subseteq }$$PSPACE⊆$${\sf{NP/poly}}$$NP/poly implies $${\sf{PSPACE} \subseteq \sf{\Sigma_2P}}$$PSPACE⊆Σ2P and (ii) $${\sf{coNP} \subseteq {\sf{NP/poly}}}$$coNP⊆NP/poly implies $${{\sf{PH} \subseteq \sf{P^{\Sigma_2P}}}}$$PH⊆PΣ2P. Of possible independent interest is a generic framework that we provide, which captures several results in the literature of the form "derandomization implies circuit lower bounds." In particular, our framework enables a unified view of our result, the one by Impagliazzo et al. (2002) mentioned above, as well as the result by Kabanets and Impagliazzo (2004) that derandomizing polynomial identity testing yields arithmetic circuit lower bounds.
Escalation Of Commitment In Groups And The Moderating Effects Of Information Framing

The escalation effect occurs when managers elect to commit additional resources to a project where the unfavorable economic prospects indicate the project should be canceled. It has been suggested that the context in which the decision is reached (e.g., a managers responsibility for the original decision to invest in a project) may influence a managers decision choices (Staw 1981). Bazerman (1984) suggests that framing of information used by decision-makers may explain the escalation effect. This study investigates whether responsibility for a prior decision will affect decision-making in interactive groups in an escalation situation. Additionally, this study looks at the effect of framing on the groups decisions and examines the ability of framing to moderate the escalation effect resulting from responsibility. The results suggest that groups are subject to escalating commitment when they are responsible for a prior related investment decision. The results also provide evidence that groups are influenced by the framing of decision-relevant information, and further, that the framing may have the ability to moderate the effects of responsibility. Implications for organizational decision making are provided.
Palladium-catalyzed cross-coupling reactions of 4-tosylcoumarin and arylboronic acids: synthesis of 4-arylcoumarin compounds

The palladium-catalyzed reaction between 4-tosylatecoumarin and arylboronic acids was investigated. This reaction provides an efficient approach to synthesize diversified 4-arylcoumarins in good yields.
Sorting, School Performance and Quality: Evidence from China

Abstract School choice reforms give talented students the option to sort out of low-performing schools but often leave disadvantaged students behind. This study shows how a Chinese city was successful in helping its low-performing schools to catch up by encouraging talented students to sort into these schools. The city identified eleven low-performing middle schools and guaranteed elite high school admission to their top ten-percent graduates. This study documents that the policy improved school performance by 0.19-0.26 standard deviations. Using data on lottery middle school assignment, I further test for potential mechanisms, including strategic sorting and improvement in school value-added.
Recent measurements of sin2b at BaBar

The angle β is the most accurately measured quantity that determines the Unitarity Triangle. In this article I review the various measurements of this angle performed by the BaBar Collaboration, and discuss their implications in the search for new physics.
Predicting online video engagement using clickstreams

As access to broadband continues to grow along with the now almost ubiquitous availability of mobile phones, the landscape of the e-content delivery space has never been so dynamic. To establish their position in the market, businesses are beginning to realize that understanding each of their customers' likes and dislikes is perhaps as important as the offered content itself. Further, a number of companies are also delivering content, product previews, advertisements, etc. via video on their sites. The question remains — how effective are video engagement channels on sites? Can that user engagement be quantified? Clickstream data can furnish important insight into those questions using videos as a communication or messaging medium. To that end, focusing on a large set of web portals owned and managed by a private media company, we propose methods using these sites' clickstream data that can be used to provide a deeper understanding of their visitors, as well as their interests and preferences. We further expand the use of this data to show that it can be effectively used to predict user engagement to video streams, quantifying that metric by means of a survival analysis assessment.
Empirically Defining Trajectories of Late-Life Cognitive and Functional Decline

BACKGROUND Alzheimer's disease (AD) is associated with variable cognitive and functional decline, and it is difficult to predict who will develop the disease and how they will progress. OBJECTIVE This exploratory study aimed to define latent classes from participants in the Alzheimer's Disease Neuroimaging Initiative (ADNI) database who had similar growth patterns of both cognitive and functional change using Growth Mixture Modeling (GMM), identify characteristics associated with those trajectories, and develop a decision tree using clinical predictors to determine which trajectory, as determined by GMM, individuals will most likely follow. METHODS We used ADNI early mild cognitive impairment (EMCI), late MCI (LMCI), AD dementia, and healthy control (HC) participants with known amyloid-β status and follow-up assessments on the Alzheimer's Disease Assessment Scale - Cognitive Subscale or the Functional Activities Questionnaire (FAQ) up to 24 months postbaseline. GMM defined trajectories. Classification and Regression Tree (CART) used certain baseline variables to predict likely trajectory path. RESULTS GMM identified three trajectory classes (C): C1 (n = 162, 13.6%) highest baseline impairment and steepest pattern of cognitive/functional decline; C3 (n = 819, 68.7%) lowest baseline impairment and minimal change on both; C2 (n = 211, 17.7%) intermediate pattern, worsening on both, but less steep than C1. C3 had fewer amyloid- or apolipoprotein-E ɛ4 (APOE4) positive and more healthy controls (HC) or EMCI cases. CART analysis identified two decision nodes using the FAQ to predict likely class with 82.3% estimated accuracy. CONCLUSIONS Cognitive/functional change followed three trajectories with greater baseline impairment and amyloid and APOE4 positivity associated with greater progression. FAQ may predict trajectory class.
Combinatorial Message Sharing and a New Achievable Region for Multiple Descriptions

This paper presents a new achievable rate-distortion region for the general $L$ channel multiple descriptions (MDs) problem. A well-known general region for this problem is due to Venkataramani, Kramer, and Goyal (VKG). Their encoding scheme is an extension of the El Gamal-Cover (EC) and Zhang–Berger (ZB) coding schemes to the $L$ channel case and includes a combinatorial number of refinement codebooks, one for each subset of the descriptions. As in ZB, the scheme also allows for a single common codeword to be shared by all descriptions. This paper proposes a novel encoding technique involving combinatorial message sharing (CMS), where every subset of the descriptions may share a distinct common message. This introduces a combinatorial number of shared codebooks along with the refinement codebooks of. These shared codebooks provide a more flexible framework to tradeoff redundancy across the messages for resilience to descriptions loss. We derive an achievable rate-distortion region for the proposed technique, and show that it subsumes the VKG region for general sources and distortion measures. We further show that CMS provides a strict improvement of the achievable region for any source and distortion measures for which some two-description subset is such that ZB achieves points outside the EC region. We then show a more surprising result: CMS outperforms VKG for a general class of sources and distortion measures, including scenarios where the ZB and EC regions coincide for all two-description subsets. In particular, we show that CMS strictly improves on VKG, for the $L$ -channel quadratic Gaussian MD problem, for all $L\geq 3$ , despite the fact that the EC region is complete for the corresponding two-descriptions problem. Consequently, the correlated quantization scheme (an extreme special case of VKG) that has been proven to be optimal for several cross sections of the $L$ -channel quadratic Gaussian MD problem is strictly suboptimal in general. Using the encoding principles derived, we show that the CMS scheme achieves the complete rate-distortion region for several asymmetric cross sections of the $L$ -channel quadratic Gaussian MD problem.
Consumers' Use of Nutrition Information When Eating Out

Until recently, many restaurants and fast-food places did not offer nutrition information at the point of purchase. This is expected to change because the 2010 Patient Protection and Affordable Care Act requires that nutrition information be posted in many of these venues. Once the law is fully implemented, it will be important to understand how it has affected consumer behavior. To establish a baseline against which to measure changes in the use of onsite nutrition information about food away from home (FAFH), we examine the demographic characteristics and dietary behaviors of U.S. consumers of FAFH before passage of the law, based on responses to the 2007-08 and 2009-10 National Health and Nutrition Examination Survey (NHANES). In particular, we examine the characteristics of consumers who use nutrition information and of those who express interest in using the information when they eat out in the future.
Elliptic curves over \(\mathbb {Q}\) and 2-adic images of Galois

We give a classification of all possible 2-adic images of Galois representations associated to elliptic curves over \(\mathbb {Q}\). To this end, we compute the ‘arithmetically maximal’ tower of 2-power level modular curves, develop techniques to compute their equations, and classify the rational points on these curves.
Simultaneous Deep Transfer Across Domains and Tasks

Recent reports suggest that a generic supervised deep CNN model trained on a large-scale dataset reduces, but does not remove, dataset bias. Fine-tuning deep models in a new domain can require a significant amount of labeled data, which for many applications is simply not available. We propose a new CNN architecture to exploit unlabeled and sparsely labeled target domain data. Our approach simultaneously optimizes for domain invariance to facilitate domain transfer and uses a soft label distribution matching loss to transfer information between tasks. Our proposed adaptation method offers empirical performance which exceeds previously published results on two standard benchmark visual domain adaptation tasks, evaluated across supervised and semi-supervised adaptation settings.
Lung cancer screening: what do long‐term smokers know and believe?

Objective To explore knowledge and beliefs of long-term smokers about lung cancer, associated risk factors and lung cancer screening. Design Qualitative study theoretically framed by the expanded Health Belief Model based on four focus group discussions. Content analysis was performed to identify themes of knowledge and beliefs about lung cancer, associated risk factors and lung cancer screening among long-term smokers' who had and had not been screened for lung cancer. Methods Twenty-six long-term smokers were recruited; two groups (n = 9; n = 3) had recently been screened and two groups (n = 7; n = 7) had never been screened. Results While most agreed lung cancer is deadly, confusion or inaccurate information exists regarding the causes and associated risk factors. Knowledge related to lung cancer screening and how it is performed was low; awareness of long-term smoking's association with lung cancer risk remains suboptimal. Perceived benefits of screening identified include: (i) finding lung cancer early; (ii) giving peace of mind; and (iii) motivation to quit smoking. Perceived barriers to screening identified include: (i) inconvenience; (ii) distrust; and (iii) stigma. Conclusions Perceived barriers to lung cancer screening, such as distrust and stigma, must be addressed as lung cancer screening becomes more widely implemented. Heightened levels of health-care system distrust may impact successful implementation of screening programmes. Perceived smoking-related stigma may lead to low levels of patient engagement with medical care and decreased cancer screening participation. It is also important to determine modifiable targets for intervention to enhance the shared decision-making process between health-care providers and their high-risk patients.
Point networks for special subspaces of $\mathbb {R}^{\kappa }$

Uniform characterizations of certain special subspaces of products of lines are presented. The characterizations all involve a collection of subsets (base, almost subbase, network or point network) organized by a directed set. New characterizations of Eberlein, Talagrand and Gulko compacta follow.
Distributed event-triggered coordination for average consensus on weight-balanced digraphs

This paper proposes a novel distributed event-triggered algorithmic solution to the multi-agent average consensus problem for networks whose communication topology is described by weight-balanced, strongly connected digraphs. The proposed event-triggered communication and control strategy does not rely on individual agents having continuous or periodic access to information about the state of their neighbors. In addition, it does not require the agents to have a priori knowledge of any global parameter to execute the algorithm. We show that, under the proposed law, events cannot be triggered an infinite number of times in any finite period (i.e., no Zeno behavior), and that the resulting network executions provably converge to the average of the initial agents' states exponentially fast. We also provide weaker conditions on connectivity under which convergence is guaranteed when the communication topology is switching. Finally, we also propose and analyze a periodic implementation of our algorithm where the relevant triggering functions do not need to be evaluated continuously. Simulations illustrate our results and provide comparisons with other existing algorithms.
A categorical view of weakest liberal preconditions

In this paper we reformulate the concepts of liberal pre- and post-conditions, and weakest liberal preconditions in a general categorical setting. We employ this setting to re-examine weakest liberal precondition semantics, and provide a new interpretation which is sounder mathematically and, we claim, more in line with what is really needed in program specification.
Metal‐Free Synthesis of Fluorinated Indoles Enabled by Oxidative Dearomatization

Nitrogen heterocycles are found in a majority of approved small-molecule pharmaceuticals, and the number of approved fluorinated drugs is increasing each decade. Therefore, new approaches for accessing fluorinated nitrogen heterocycles are of great significance. A novel, scalable, and metal-free method for accessing a wide range of fluorinated indoles is described. This oxidative-dearomatization-enabled approach assembles 2-trifluoromethyl NH-indole products from simple commercially available anilines with hexafluoroacetylacetone in the presence of an organic oxidant. The nature of the aniline N-capping group is critical for the success of this new reaction. Furthermore, the indole products contain a 3-trifluoroacetyl group, which can be exploited to access a plethora of useful functional groups.
Diverging Overland Flow

Kinematic wave theory is utilized to investigate diverging overland flow which does not appear to have been previously investigated in watershed hydrology. This paper is the first in a sequel of two. It developes analytical solutions for a diverging geometry for two cases: (1) when infiltration is considered through rainfall-excess, and (2) when infiltration is treated concurrently with runoff; this gives rise to a free boundary problem. Part II discusses the application of the proposed model to natural watersheds.
Saturation Numbers in Tripartite Graphs

Given graphs H and F, a subgraph is an F-saturated subgraph of H if , but for all . The saturation number of F in H, denoted , is the minimum number of edges in an F-saturated subgraph of H. In this article, we study saturation numbers of tripartite graphs in tripartite graphs. For and n1, n2, and n3 sufficiently large, we determine and exactly and within an additive constant. We also include general constructions of -saturated subgraphs of with few edges for .
Relative Performance of Semi-Parametric Nonlinear Models in Forecasting Basis

Many risk management strategies, including hedging the price risk using forward or futures contracts require accurate forecasts of basis, i.e., spot price minus the futures price. Recent literature in this area has applied nonlinear time-series models, which are refinements of the linear autoregressive models that allow the parameters to transition from one regime to another. These parametric nonlinear models, however, involve complex estimation problems, and may diminish forecasting accuracy, especially in longer horizons. We propose using a semi-parametric, generalized additive model (GAM) that may improve the forecasting performance with its simplicity and flexibility while still accounting for nonlinearities in local prices and basis. Empirical results based on weekly futures and spot prices for North Carolina soybean and corn markets support evidence of nonlinear effects in basis. In general, generalized additive models seem to yield better forecasts of basis.
Identification of the Bile Acid Transporter Slco1a6 as a Candidate Gene That Broadly Affects Gene Expression in Mouse Pancreatic Islets

We surveyed gene expression in six tissues in an F2 intercross between mouse strains C57BL/6J (abbreviated B6) and BTBR T(+) tf/J (abbreviated BTBR) made genetically obese with the Leptin(ob) mutation. We identified a number of expression quantitative trait loci (eQTL) affecting the expression of numerous genes distal to the locus, called trans-eQTL hotspots. Some of these trans-eQTL hotspots showed effects in multiple tissues, whereas some were specific to a single tissue. An unusually large number of transcripts (∼8% of genes) mapped in trans to a hotspot on chromosome 6, specifically in pancreatic islets. By considering the first two principal components of the expression of genes mapping to this region, we were able to convert the multivariate phenotype into a simple Mendelian trait. Fine mapping the locus by traditional methods reduced the QTL interval to a 298-kb region containing only three genes, including Slco1a6, one member of a large family of organic anion transporters. Direct genomic sequencing of all Slco1a6 exons identified a nonsynonymous coding SNP that converts a highly conserved proline residue at amino acid position 564 to serine. Molecular modeling suggests that Pro564 faces an aqueous pore within this 12-transmembrane domain-spanning protein. When transiently overexpressed in HEK293 cells, BTBR organic anion transporting polypeptide (OATP)1A6-mediated cellular uptake of the bile acid taurocholic acid (TCA) was enhanced compared to B6 OATP1A6. Our results suggest that genetic variation in Slco1a6 leads to altered transport of TCA (and potentially other bile acids) by pancreatic islets, resulting in broad gene regulation.
Structure of the airflow above surface waves

AbstractIn recent years, much progress has been made to quantify the momentum exchange between the atmosphere and the oceans. The role of surface waves on the airflow dynamics is known to be significant, but our physical understanding remains incomplete. The authors present detailed airflow measurements taken in the laboratory for 17 different wind wave conditions with wave ages [determined by the ratio of the speed of the peak waves Cp to the air friction velocity u* (Cp/u*)] ranging from 1.4 to 66.7. For these experiments, a combined particle image velocimetry (PIV) and laser-induced fluorescence (LIF) technique was developed. Two-dimensional airflow velocity fields were obtained as low as 100 μm above the air–water interface. Temporal and spatial wave field characteristics were also obtained. When the wind stress is too weak to generate surface waves, the mean velocity profile follows the law of the wall. With waves present, turbulent structures are directly observed in the airflow, whereby low-horizon...
Capital Flows, Financial Intermediation and Macroprudential Policies

This paper develops an open-economy DSGE model with an optimizing banking sector to assess the role of capital flows, macro-financial linkages, and macroprudential policies. The key result is that macroprudential measures can usefully complement monetary policy. Countercyclical macroprudential polices can help reduce macroeconomic volatility and enhance welfare. The results also demonstrate the importance of capital flows and financial stability for business cycle fluctuations as well as the role of supply side financial accelerator effects in the amplification and propagation of shocks.
Ir(I)-Catalyzed Enantioselective Decarboxylative Allylic Etherification: A General Method for the Asymmetric Synthesis of Aryl Allyl Ethers

Ir(I)-catalyzed enantioselective decarboxylative allylic etherification of aryl allyl carbonates provides aryl allyl ethers. Key to the generality and high stereoselection of the reaction is the use of the intramolecular decarboxylative allylation process and [Ir(dbcot)Cl]2 as an Ir(I) source. Ir(I)-catalyzed diastereoselective decarboxylative allylic etherification, combined with asymmetric aldehyde crotylation and cross metathesis, can furnish monoprotected 2-methyl-1,3-diols (starting from simple aldehydes) with high diastereoselectivities.
The reaction of 2,3,4-trichlorothiophene with alkyllithium reagents

2,3,4-Trichlorothiophene undergoes metal-hydrogen exchange with one equivalent of butyllithium inTHF at −78°C to give trichloro-2-thienyllithium in 91% yield. No metal-halogen exchange is observed to have taken place. Witht-butyllithium under similar conditions, however, the metalhalogen exchange reaction occurs but only to the extent of 8%; the main reaction remains to be the metal-hydrogen exchange. 2,3,4-Trichlorothiophene reacts with two equivalents of butyllithium in ether at −5°C to give 3,4-dichloro-2,5-dilithiothiophene in 96% yield.
SHORT-WAVELENGTH INSTABILITIES OF RIEMANN ELLIPSOIDS

Perturbations of incompressible S-type Riemann ellipsoids are considered in the limit of short wavelength. This complements the classical consideration of perturbations of long wavelength. It is shown that there is very little of the parameter space in which the laminar, steady-state flow can exist in a stable state. This confirms, in a physically consistent framework, hydrodynamic-stability results previously obtained in the context of unbounded, two-dimensional flows. The configurations stable to perturbations of arbitrarily short wavelength include the rigidly rotating configurations of Maclaurin and Jacobi, as well as a narrow continuum centred on the family of irrotational ellipsoids and including the non-rotating sphere. However, most configurations departing even slightly from axial symmetry are unstable. Some of the implications of these results for the complexity of astrophysical flows are discussed.
Optical Waveguides in the Computer Environment a Packaging Perspective

Fiber optics has had a major impact on the technology of the telecommunications industry but has made little impact on the computer industry. One reason for this is the incompatability of present day optoelectronic component packaging technology with the needs of the computer industry. This problem is most evident in high-performance computer packaging.
Synthesis and late-stage functionalization of complex molecules through C-H fluorination and nucleophilic aromatic substitution.

We report the late-stage functionalization of multisubstituted pyridines and diazines at the position α to nitrogen. By this process, a series of functional groups and substituents bound to the ring through nitrogen, oxygen, sulfur, or carbon are installed. This functionalization is accomplished by a combination of fluorination and nucleophilic aromatic substitution of the installed fluoride. A diverse array of functionalities can be installed because of the mild reaction conditions revealed for nucleophilic aromatic substitutions (SNAr) of the 2-fluoroheteroarenes. An evaluation of the rates for substitution versus the rates for competitive processes provides a framework for planning this functionalization sequence. This process is illustrated by the modification of a series of medicinally important compounds, as well as the increase in efficiency of synthesis of several existing pharmaceuticals.
Applied Force and Second Order Transitions of Rubber

Abstract Second-order transitions, which appear to mark the change from brittleness to elasticity, are well known for rubber and numerous other polymers. The temperature at which such a transition occurs depends, among other things, on the kind of polymer, on the additives that are in it, and on how much it is cross-linked. It would also appear reasonable to expect that the second-order transition temperature would depend on the deformation of the sample, such as the elongation of a rubber strip. Accordingly, the research here reported was undertaken to investigate the effect of tension on rubber, in particular on rubbers with different degrees of cross-linking. The effect of such deformations might well provide further evidence regarding the nature of the phenomenon itself. Three different cures of natural rubber were used for comparing cross-linking effects. In addition, a sample of GR-S and a sample of rubber reinforced with carbon black were included for comparison. A decrease of Tm, the transition te...
From highly enantioselective catalytic reaction of 1,3-diynes with aldehydes to facile asymmetric synthesis of polycyclic compounds.

(S)-1,1′-Binaphth-2-ol (BINOL) in combination with ZnEt2, Ti(OiPr)4, and biscyclohexylamine was found to catalyze the highly enantioselective (83–95% ee) addition of various 1,3-diynes to aldehydes of diverse structures. This method provides a convenient pathway to generate a number of optically active dienediynes as the acyclic precursors to polycyclic compounds. The chiral dienediynes undergo highly chemoselective Pauson–Khand (PK) cycloaddition in benzaldehyde by using [Rh(cod)Cl]2 as the catalyst in the presence of rac-BINAP. High diastereoselectivity (up to >20:1) has also been achieved with the chiral dienediyne substrates containing a bulky substituent adjacent to the chiral center. In the presence of the Grubbs II catalyst, ring-closing enyne metathesis of the PK cycloaddition products led to the formation of the desired 5,5,7- and 5,5,8-fused tricyclic compounds. Further highly diastereoselective Diels–Alder reaction of a 5,5,7-tricyclic compound with maleic anhydride produced a 5,5,7,6-polycycli...
Kramers turnover: From energy diffusion to spatial diffusion using metadynamics

We consider the rate of transition for a particle between two metastable states coupled to a thermal environment for various magnitudes of the coupling strength using the recently proposed infrequent metadynamics approach [P. Tiwary and M. Parrinello, Phys. Rev. Lett. 111, 230602 (2013)]. We are interested in understanding how this approach for obtaining rate constants performs as the dynamics regime changes from energy diffusion to spatial diffusion. Reassuringly, we find that the approach works remarkably well for various coupling strengths in the strong coupling regime, and to some extent even in the weak coupling regime.
Protecting civilians in civil war The institution of the ATCC in Colombia

Can local organizations give civilians the capacity to protect themselves from civil war violence? Civilians have traditionally been considered powerless when facing armed groups but new research suggests organized communities may promote security through nonviolent strategies such as resolving disputes between neighbors and managing relations with macro-armed actors. This article analyzes whether and how these ‘mechanisms’ designed to retain community autonomy functioned in the community-case of the Peasant Worker Association of the Carare River (ATCC) in Colombia. The Carare civilians developed a local institutional process to investigate threats against suspected armed group collaborators to clarify the ‘fog of war’ and reform civilian preferences to participate in the conflict. This process is evaluated in reference to existing hypotheses about violence in civil wars such as the balance of territorial control using qualitative evidence from original field research. A unique within-case database create...
Trajectory clustering of estradiol and follicle-stimulating hormone during the menopausal transition among women in the study of women's health across the nation (SWAN)

The start of the menopausal transition in most women is marked by irregularity of the menstrual cycle. Irregularity appears to correspond to changes in estrogen and follicle-stimulating hormone (FSH) levels. Variations in the pattern of change in the trajectories of estradiol (E2) and FSH during the menopause transition have not been defined well. The Study of Women’s Health Across the Nation (SWAN) is a large multicenter, multiethnic longitudinal study of the menopausal transition. These investigators used data from SWAN to determine whether different trajectories of E2 and FSH could be identified and whether the different trajectories were related to body mass index (BMI) and race/ethnicity. The study population included 1316 postmenopausal women aged 42 to 52 years who had at least 12 months of amenorrhea not due to surgical removal of uterus and/or both ovaries or no exposure to hormone therapy before the final menstrual period (FMP). All participants were seen at 7 sites and had up to 11 annual visits for measurement of serum E2 and FSH levels. The study sample was composed of white women (42.5%); racial/ethnic groups included African Americans (31.4%), Chinese (10.0%), Japanese (10.7%), and Hispanics (5.4%). At baseline, 32.1% of women were obese. Primary study outcome measures were the annual serum E2 and FSH levels anchored to the FMP. Four distinct E2 trajectories across the FMP were identified: slow decline (26.9% of the sample), flat (28.6%), rise/slow decline (13.1%), and rise/steep decline (31.5%). Three FSH trajectories across the FMP were identified: low (10.6%), medium (48.7%), and high (40.7%) rising patterns. Body mass index and race/ethnicity were related significantly to the E2 and FSH trajectories (P These findings show that changes in E2 and FSH trajectories occurring over the menopausal transition are not uniform across this study population. The differing hormone trajectories during the menopausal transition were strongly related to BMI and race/ethnicity.