cssi/SciSciGPT-SciSciNet huggingface dataset:
Dynamic Panics: Theory and Application to the Eurozone

It is shown in a standard quantitative model of sovereign debt and default that sentiment shocks can alter the distribution of fundamental defaults. The channel through which this occurs is a new type of dynamic lender coordination problem in sovereign debt markets that I call a dynamic panic. During a dynamic panic of this kind, expectations of future negative investor sentiments dilute the price of long-term debt; the sovereign's optimal response to such a panic can be to borrow aggressively, which justifies investors' fears of dilution. Such panics generate naturally many of the unique features the recent Eurozone crisis, and so I explore policy implications in this environment. I find that rate ceilings are an ineffective policy tool but that liquidity provision, appropriately implemented, can eliminate such panics.
Phase Transition, Conformational Exchange, and Nonlinear Optical Third Harmonic Generation of ACsP2Se8 (A = K, Rb, Cs)

The soluble molecular selenophosphate salts ACsP2Se8 (A = K, Rb, Cs) crystallize in the orthorhombic space group Ccce with a = 14.982(3) A, b = 24.579(5) A, and c = 13.065(3) A for the Cs salt and a = 14.782(3) A, b = 23.954(5) A, and c = 13.044(3) A for the K analogue. ACsP2Se8 is composed of the molecular 6-membered ring, [P2Se8]2−, in the twist conformation charge balanced by alkali metals. The band gaps of these compounds are 2.44 ± 0.2 eV for Cs2P2Se8, 2.41 ± 0.2 eV for RbCsP2Se8, and 2.36 ± 0.2 eV for KCsP2Se8. The amorphous versions of these materials can be made by water quenching the melt and have band gaps for all ACsP2Se8 of 2.12 ± 0.2 eV. Raman spectroscopic studies exhibit active modes of PSe4 and Se−Se in the compound. Solution 31P NMR studies shed light into the interesting conformational fluxionality of the [P2Se8]2− anion, including a conformation that has not been previously observed. Thermal analysis reveals ACsP2Se8 exhibits a phase transition, which we investigate by in situ synchrotr...
Special Issue on Smart and Resilient Transportation Infrastructure

Smart Infrastructure (SI) is the infrastructure composed of materials or structures that can sense the environmental or status changes and adapt to the changes for positive effects. It may simply consist of smart materials that can adapt to temperature changes or stress status, or a structure that includes smart sensors to help the structure to perform adaptations. SI technologies have resulted from the integration and deployment of innovative technologies developed from several NSF initiatives on sensing technology, information technology, high performance materials, cyber infrastructure, and computational science and engineering. SI has most recently emerged as an important initiative for National Institute of Standards and Technology (NIST), Federal Highway Administration (FHWA), Department of Defense (DoD), Department of Homeland Security (DHS), and Department of Energy (DoE).
TOTAL KNEE REVISION: A DAY IN THE LIFE OF …

To wake up in the morning facing a complex total hip revision can be unpleasant. Modern designs have greatly facilitated dealing with the most difficult revision situations both on the acetabular and femoral side. The surgeon faces blood loss, dislocation, infection, and a litany of other potential complications. Our advances in total hip revision have been outstanding but can pose very complex issues. Total knee revision on the other hand is easier. The surgeon needs to ask a series of questions pre-operatively and intra-operatively. Pre-operatively, one must know the mechanism of failure. You also need to know “what is missing” in terms of skin, soft tissue, extensor mechanism, bone and ligaments. Intra-operatively, the surgeon must know the difference between the flexion and extension gap, the position of the joint line, the extent of the bone loss and whether it is load bearing or non-load bearing, the ligamentous stability and the intramedullary shaft. Most modern knee revision designs allow the surgeon to create a paradigm to deal with all of these potential problems. There, of course, are complex problems of malalignment, periprosthetic fracture and other deformities that add a level of complexity but most of these can be dealt with using standard revision designs without requiring custom prostheses.
Diabetes Care and Research: What Should Be the Next Frontier?

EDITOR’S NOTE: This article is adapted from the address of the American Diabetes Association (ADA) President, Health Care and Education, given in June 2015 at the Association’s 75th Scientific Sessions in Boston, Mass. A webcast of this speech is available for viewing at the ADA website (http://professional.diabetes.org/webcasts).
Shear Degradation of Polyisobutene

A polyisobutene of Mw 1.98 × 106, Mw/Mn 1.8, was extruded in an Instron capillary rheometer. Shear degradation occurred at high shear stresses, approaching melt fracture, and was more prominent at lower extrusion temperatures for tests at 60–140°C. The capillary was 2.0 in. long with a length/diameter ratio of 66.7 and a 90° entrance angle. Repetitive extrusions at constant shear rate caused a decrease in a molecular weight and a simultaneous narrowing of the molecular weight distribution. Extrudate expansion was measured after each successive capillary pass for tests at 80°C. Extrudate swelling correlated well with (Mz+1) Mz/Mw, except for the two first passes, where melt fracture was pronounced. The correlation with equilibrium extrudate expansion was almost as good for (Mz/Mw)3.7 (Mill's correlation) and for Mz+1 alone. The efficiency of bond rupture is low, with the energy required to rupture 1 mole of bonds being about 200,000 kcal at 80°C.
Evaluation of commercially available RNA amplification kits for RNA sequencing using very low input amounts of total RNA

This article includes supplemental data. Please visit http://www.fasebj.org to obtain this information.Multiple recent publications on RNA sequencing (RNA-seq) have demonstrated the power of next-generation sequencing technologies in whole-transcriptome analysis. Vendor-specific protocols used for RNA library construction often require at least 100 ng total RNA. However, under certain conditions, much less RNA is available for library construction. In these cases, effective transcriptome profiling requires amplification of subnanogram amounts of RNA. Several commercial RNA amplification kits are available for amplification prior to library construction for next-generation sequencing, but these kits have not been comprehensively field evaluated for accuracy and performance of RNA-seq for picogram amounts of RNA. To address this, 4 types of amplification kits were tested with 3 different concentrations, from 5 ng to 50 pg, of a commercially available RNA. Kits were tested at multiple sites to assess reproducibility and ease of use. The human total reference RNA used was spiked with a control pool of RNA molecules in order to further evaluate quantitative recovery of input material. Additional control data sets were generated from libraries constructed following polyA selection or ribosomal depletion using established kits and protocols. cDNA was collected from the different sites, and libraries were synthesized at a single site using established protocols. Sequencing runs were carried out on the Illumina platform. Numerous metrics were compared among the kits and dilutions used. Overall, no single kit appeared to meet all the challenges of small input material. However, it is encouraging that excellent data can be recovered with even the 50 pg input total RNA.
The impact of neoadjuvant therapy for gastroesophageal adenocarcinoma on postoperative morbidity and mortality.

Background and Objectives We sought to study the impact of neoadjuvant therapy (NAT) on postoperative complications following surgical resection of adenocarcinomas of the stomach and gastroesophageal junction (GEJ). Methods We compared the postoperative outcomes of 308 patients undergoing a surgery-first approach and 145 patients undergoing NAT followed by curative-intent surgery for adenocarcinomas of the stomach and GEJ from 1995–2014. Results Patients receiving NAT were more likely to be younger, have tumors of the GEJ, to undergo esophagogastrectomy and D2 lymphadenectomy, and to have more advanced stage disease than patients undergoing surgery first. There were no differences in overall 30-day morbidity or mortality rates between the groups, yet patients undergoing surgery first were more likely to have higher-grade complications than those undergoing NAT. Age >65 years, higher ASA score, concomitant splenectomy, more advanced tumor stage, and year of surgery were independent risk factors for postoperative morbidity, but receipt of NAT was not an independent predictor of postoperative morbidity. Conclusions Despite having more advanced disease and undergoing higher-risk surgical procedures, patients with adenocarcinomas of the stomach or GEJ who receive NAT prior to surgery are no more likely to suffer postoperative complications than patients treated with a surgery-first approach. J. Surg. Oncol. 2016;113:560–564. © 2016 Wiley Periodicals, Inc.
Putting the Patient in Patient Reported Outcomes: A Robust Methodology for Health Outcomes Assessment.

Summary When analyzing many health-related quality-of-life (HRQoL) outcomes, statistical inference is often based on the summary score formed by combining the individual domains of the HRQoL profile into a single measure. Through a series of Monte Carlo simulations, this paper illustrates that reliance solely on the summary score may lead to biased estimates of incremental effects, and I propose a novel two-stage approach that allows for unbiased estimation of incremental effects. The proposed methodology essentially reverses the order of the analysis, from one of ‘aggregate, then estimate’ to one of ‘estimate, then aggregate’. Compared to relying solely on the summary score, the approach also offers a more patient-centered interpretation of results by estimating regression coefficients and incremental effects in each of the HRQoL domains, while still providing estimated effects in terms of the overall summary score. I provide an application to the estimation of incremental effects of demographic and clinical variables on HRQoL following surgical treatment for adult scoliosis and spinal deformity. Copyright © 2014 John Wiley & Sons, Ltd.
2D and 3D heterogeneous photonic integrated circuits

This paper reviews 2D and 3D photonic integrated circuits and their applications in computing, networking, and signal processing. Various novel fabrication techniques leading to realization of chip-scale microsystems, and future prospects will also be discussed.
Ni-catalyzed alkenylation of triazolopyridines: synthesis of 2,6-disubstituted pyridines.

A synthetic strategy to access 2,6-disubstituted pyridines from triazolopyridines through a regioselective nickel-catalyzed alkenylation reaction of the C7–H bond is described. The N2 fragment embedded in the resulting C–H functionalized triazolopyridine can be readily excised using acidic or oxidative conditions to unmask the pyridine.
The Role of the Society of Motion Picture and Television Engineers in Audio Standardization

The SMPTE, through its Engineering Committees, generates standards which aid in producing better quality sound for motion-picture and television audiences. Standards specify film and magnetic stripe dimensions; location, dimensions and reproducing characteristics of audio records; techniques for assessing recorded sound quality; and test films for checking and aligning sound recording and reproducing equipment. A complete list is presented and typical standards are described.
Molecular rotors--fluorescent biosensors for viscosity and flow.

Viscosity is a measure of the resistance of a fluid against gradients in flow (shear rate). Both flow and viscosity play an important role in all biological systems from the microscopic (e.g., cellular) to the systemic level. Many methods to measure viscosity and flow have drawbacks, such as the tedious and time-consuming measurement process, expensive instrumentation, or the restriction to bulk sample sizes. Fluorescent environment-sensitive dyes are known to show high sensitivity and high spatial and temporal resolution. Molecular rotors are a group of fluorescent molecules that form twisted intramolecular charge transfer (TICT) states upon photoexcitation and therefore exhibit two competing deexcitation pathways: fluorescence emission and non-radiative deexcitation from the TICT state. Since TICT formation is viscosity-dependent, the emission intensity of molecular rotors depends on the solvent's viscosity. Furthermore, shear-stress dependency of the emission intensity was recently described. Although the photophysical processes are widely explored, the practical application of molecular rotors as sensors for viscosity and the fluid flow introduce additional challenges. Intensity-based measurements are influenced by fluid optical properties and dye concentration, and solvent–dye interaction requires calibration of the measurement system to a specific solvent. Ratiometric dyes and measurement systems help solve these challenges. In addition, the combination of molecular rotors with specific recognition groups allows them to target specific sites, for example the cell membrane or cytoplasm. Molecular rotors are therefore emerging as new biosensors for both bulk and local microviscosity, and for flow and fluid shear stress on a microscopic scale and with real-time response.
Aerobic Copper-Catalyzed O-Methylation with Methylboronic Acid

The oxidative coupling of alkylboronic acids with oxygen nucleophiles offers a strategy for replacing toxic, electrophilic alkylating reagents. Although the Chan–Lam reaction has been widely applied in the arylation of heteroatom nucleophiles, O-alkylation with boronic acids is rare. We report a Cu-catalyzed nondecarboxylative methylation of carboxylic acids with methylboronic acid that proceeds in air with no additional oxidant. An isotope-labeling study supports an oxidative cross-coupling mechanism, in analogy to that proposed for Chan–Lam arylation.
Chemiluminescent measurement of increased free radical formation after ischemia/reperfusion : mechanisms of free radical formation in the liver

It has been proposed that xanthine oxidase-derived superoxide mediates reperfusion injury in the liver; however, there is a little direct evidence to support this hypothesis. In this paper we describe a model system to directly and noninvasively measure oxyradical formation and hepatic injury in isolated perfused rat liver. Using this sensitive chemiluminescent technique, we clearly demonstrate the theorized burst in oxygen radical production upon reperfusion of previously ischemic liver, without perturbing the system with chemical luminescence enhancers. This increase in chemiluminescence (CL) upon reperfusion was diminished by the free radical scavengers trolox and ascorbate, as well as N-2-mercaptoproprionyl-glycine (MPG), thereby confirming the oxyradical nature of this signal. Additionally, superoxide dismutase and the xanthine oxidase inhibitor allopurinol, but not catalase, attenuated the reperfusion effect, providing the most direct evidence so far that XOD derived superoxide anion is formed during liver reperfusion. Hepatic injury (AST release) did not appear to relate to increased CL, supporting the notion that the oxyradical flux may serve as a signal for other events leading to tissue injury. Further studies using this sensitive chemiluminescent technique should aid in delineating the detailed mechanism(s) of reperfusion injury.
Effect of Finite Extensibility on the Viscoelastic Properties of a Styrene-Butadiene Rubber Vulcanizate in Simple Tensile Deformations up to Rupture

Stress–strain and rupture data were determined on an unfilled styrene–butadiene vulcanizate at temperatures from −45 to 35°C and at extension rates from 0.0096 to 9.6 min−1. The data were represented by four functions: (1) the well-known temperature function (shift factor) aT; (2) the constant strain rate modulus, F(t,T), reduced to temperature T0 and time t/aT, i.e., T0F(t/aT)/T; (3) the time-dependent maximum extensibility, λm(t/aT); and (4) a function Ω(χ) where χ = (λ − 1)λm0/λm, in which λ is the extension ratio and λm0 is the maximum extensibility under equilibrium conditions. The constant strain rate modulus characterizes the stress–time response to a constant extension rate at small strains, within the range of linear response; λm is a material parameter needed to represent the response at large λ; and Ω(χ) represents the stress–strain curve of the material in a reference state of unit modulus and λm = λm. The shift factor aT was found to be sensibly independent of extension. At all values of t/aT for which the maximum extensibility is time-independent, the relaxation rate was also found to be independent of λ. These observations indicate that the monomeric friction coefficient is strain-independent over the ranges of T and λ covered in the present study. It was found that λm0 = 8.6 and that the largest extension ratio at break, (λb)max, is 7.3. Thus, rupture always occurs before the network is fully extended.
Ring-strain-enabled reaction discovery: new heterocycles from bicyclo[1.1.0]butanes.

ConspectusMechanistically as well as synthetically, bicyclo[1.1.0]butanes represent one of the most fascinating classes of organic compounds. They offer a unique blend of compact size (four carbon atoms), high reactivity (strain energy of 66 kcal/mol), and mechanistic pathway diversity that can be harvested for the rapid assembly of complex scaffolds. The C(1)–C(3) bond combines the electronic features of both σ and π bonds with facile homolytic and heterolytic bond dissociation properties and thereby readily engages pericyclic, transition-metal-mediated, nucleophilic, and electrophilic pathways as well as radical acceptor and donor substrates.Despite this multifaceted reaction profile and recent advances in the preparation of bicylo[1.1.0]butanes, the current portfolio of synthetic applications is still limited compared with those of cyclopropanes and cyclobutanes. In this Account, we describe our work over the past decade on the exploration of substituent effects on the ring strain and the reactivity of...
Learning Visual Storylines with Skipping Recurrent Neural Networks

What does a typical visit to Paris look like? Do people first take photos of the Louvre and then the Eiffel Tower? Can we visually model a temporal event like “Paris Vacation” using current frameworks? In this paper, we explore how we can automatically learn the temporal aspects, or storylines of visual concepts from web data. Previous attempts focus on consecutive image-to-image transitions and are unsuccessful at recovering the long-term underlying story. Our novel Skipping Recurrent Neural Network (S-RNN) model does not attempt to predict each and every data point in the sequence, like classic RNNs. Rather, S-RNN uses a framework that skips through the images in the photo stream to explore the space of all ordered subsets of the albums via an efficient sampling procedure. This approach reduces the negative impact of strong short-term correlations, and recovers the latent story more accurately. We show how our learned storylines can be used to analyze, predict, and summarize photo albums from Flickr. Our experimental results provide strong qualitative and quantitative evidence that S-RNN is significantly better than other candidate methods such as LSTMs on learning long-term correlations and recovering latent storylines. Moreover, we show how storylines can help machines better understand and summarize photo streams by inferring a brief personalized story of each individual album.
Acetylation regulates DNA repair mechanisms in human cells

The p300-mediated acetylation of enzymes involved in DNA repair and replication has been previously shown to stimulate or inhibit their activities in reconstituted systems. To explore the role of acetylation on DNA repair in cells we constructed plasmid substrates carrying inactivating damages in the EGFP reporter gene, which should be repaired in cells through DNA mismatch repair (MMR) or base excision repair (BER) mechanisms. We analyzed efficiency of repair within these plasmid substrates in cells exposed to deacetylase and acetyltransferase inhibitors, and also in cells deficient in p300 acetyltransferase. Our results indicate that protein acetylation improves DNA mismatch repair in MMR-proficient HeLa cells and also in MMR-deficient HCT116 cells. Moreover, results suggest that stimulated repair of mismatches in MMR-deficient HCT116 cells is done though a strand-displacement synthesis mechanism described previously for Okazaki fragments maturation and also for the EXOI-independent pathway of MMR. Loss of p300 reduced repair of mismatches in MMR-deficient cells, but did not have evident effects on BER mechanisms, including the long patch BER pathway. Hypoacetylation of the cells in the presence of acetyltransferase inhibitor, garcinol generally reduced efficiency of BER of 8-oxoG damage, indicating that some steps in the pathway are stimulated by acetylation.
Large-scale dynamo action precedes turbulence in shearing box simulations of the magnetorotational instability

We study the dynamo generation (exponential growth) of large scale (planar averaged) fields in unstratified shearing box simulations of the magnetorotational instability (MRI). In contrast to previous studies restricted to horizontal ($x$-$y$) averaging, we demonstrate the presence of large scale fields when either horizontal or vertical ($y$-$z$) averaging is employed. By computing planar averaged fields and power spectra, we find large scale dynamo action in the early MRI growth phase---a previously unidentified feature. Fast growing horizontal low modes and fiducial vertical modes over a narrow range of wave numbers amplify these planar averaged fields in the MRI growth phase, before turbulence sets in. The large scale field growth requires linear fluctuations but not nonlinear turbulence (as defined by mode-mode coupling) and grows as a direct global mode of the MRI. Only by vertical averaging, can it be shown that the growth of horizontal low wavenumber MRI modes directly feed-back to the initial vertical field providing a clue as to why the large scale vertical field sustains against turbulent diffusion in the saturation regime. We compute the terms in the planar averaged mean field equations to identify the individual contributions to large scale field growth for both vertical and horizontal averaging. The large scale fields obtained from such vertical averaging are found to compare well with global cylindrical simulations and quasilinear analytical analysis from a previous study by Ebrahimi \& Blackman. We discuss the potential implications of these new results for understanding large scale MRI dynamo saturation and turbulence.
George Urdang in Madison: as I remember him.

George Urdang eut une influence significative dans le developpement de l'histoire de la pharmacie, et dans le traitement des decouvertes dans le domaine pharmaceutique. L'auteur, assistant et collaborateur d'Urdang, livre ici les memoires d'une cooperation entre 1948 et 1960 en ne manquant pas de rappeler les qualites humaines et professionnelles de son prestigieux collaborateur...
The role of inequality in climate-poverty debates

There is no doubt that the poorest people are already and will continue to be most severely impacted by climatic changes, including shifting trends as well as more frequent and severe extreme events. Yet, new insights on the dynamics and distribution of poverty point to the need to comprehend where the poor and poorest are, how they are poor, and why their poverty constrains their abilities to cope with and adapt to occurring and predicted changes. This paper draws on a diverse and growing literature on climate change and poverty to argue that uneven power relations more so than exposure and sensitivity to climatic hazards make the poor and disadvantaged distinctly more vulnerable than more affluent, privileged, and powerful groups and individuals. Further, climatic stressors and climate change as well as climate policies, often entangled with social exclusion and institutional neglect, compound the issue of poverty and exacerbate human precariousness, hence acting as a threat multiplier. The paper compares different approaches to assessing poverty, and explores structural processes and power dynamics that drive or perpetuate inequalities. The paper also investigates how the currently nonpoor may become transient or chronic poor, how climate change may exacerbate poverty traps, and how interventions to curb emissions and multidimensional poverty may be tackled to pursue climate-resilient development pathways.
A tight lower bound for Szemerédi’s regularity lemma

We determine the order of the tower height for the partition size in a version of Szemeredi’s regularity lemma. This addresses a question of Gowers.
Semantic provenance for science data products: application to image data processing

A challenge in providing scientific data services to a broad user base is to also provide the metadata services and tools the user base needs to correctly interpret and trust the provided data. Provenance metadata is especially vital to establishing trust, giving the user information on the conditions under which the data originated and any processing that was applied to generate the data product provided. In this paper, we describe our work on a federated set of data services in the area of solar coronal physics. These data services provide a particular challenge because there is decades of existing data whose provenance we will have to reconstruct, and because the quality of the final data product is highly sensitive to data capture conditions, information which is not currently propagated with the data. We describe our use of semantic technologies for encoding provenance and domain knowledge and show how provenance and domain ontologies can be used together to satisfy complex use cases. We show our progress on provenance search and visualization tools and highlight the need for semantics in the user tools. Finally, we describe how our methods are applicable to generic data processing systems.
Comparison of Student Achievement Using Didactic, Inquiry-Based, and the Combination of Two Approaches of Science Instruction

Science educators and administrators support the idea that inquiry-based and didactic-based instructional strategies have varying effects on students' acquisition of science concepts. The research problem addressed whether incorporating the two approaches covered the learning requirements of all students in science classes, enabling them to meet state and national standards. The optimal teaching method, didactic (teacher-directed), inquiry-based, or a combination of two approaches instructional method, becomes essential if students are to discover ways to learn information. Locally, the results indicated greater and statistically significant differences in standardized laboratory scores for students who were taught using the combination of two approaches. Based on these results, biology instructors will gain new insights into ways of improving the instructional process. Social change may occur as the science curriculum leadership applies the combination of two instructional approaches to improve acquisition of science concepts by biology students.
Asthma in the elderly.

The older population has seen the greatest increase in the prevalence of current asthma in recent years. Asthma may begin at any age and when it occurs at an advanced as opposed to a young age, it is often nonatopic, severe, and unremitting. Unfortunately, geriatric-specific guidelines are not available for the diagnosis and treatment of asthma. However, with objective monitoring, avoidance of asthma triggers, appropriate pharmacotherapy, and patient education, the disease can be managed successfully.
Differences in perceptions of communication quality between a Twitterbot and human agent for information seeking and learning

Twitters design allows the implementation of automated programs that can submit tweets, interact with others, and generate content based on algorithms. Scholars and end-users alike refer to these programs to as Twitterbots. This two-part study explores the differences in perceptions of communication quality between a human agent and a Twitterbot in the areas of cognitive elaboration, information seeking, and learning outcomes. In accordance with the Computers Are Social Actors (CASA) framework (Reeves & Nass, 1996), results suggest that participants learned the same from either a Twitterbot or a human agent. Results are discussed in light of CASA, as well as implications and directions for future studies. Twitterbots were compared to human agents for information seeking and learning.Two experimental studies were conducted.No differences in cognitive elaboration and information seeking.No differences in affective learning and motivation.Twitterbots may be effective agents for communication in social media environments.
Introduction: Technology-Based Economic Development and the Initiatives that Advance it

In today’s usage, a technopolis is a region trying to build and maintain a healthy, technology-driven economy. Regions that succeed are likely to have: A robust local value chain including strong R&D, manufacturing, marketing and distribution, and intensive international connections. A critical mass of companies in one or more well-defined “clusters.” A relatively compact geography. This allows a successful specialized economy, impossible in more sprawling, diverse places (which may well have a greater total high-technology employment – see Markusen et al. 2001). Technopolis regions grow by: Attracting new companies Nurturing existing indigenous firms Encouraging entrepreneurial start-ups Providing a supportive and innovative educational, social, tax, qualityof- life, cultural, institutional and hard-infrastructural context for research, technology entrepreneurship, and business, and Reaching out to other technopoleis for networking purposes.
Robust game theoretic synthesis in the presence of uncertain initial states and system parameters

A game theoretic approach to linear control synthesis is developed in which initial states and system parameter uncertainties are included as adversaries. The /spl Hscr//sub /spl infin// performance constraint is imbedded in the synthesis formulation by penalizing the process and measurement disturbances in the game cost criterion. The resulting controller requires a solution to an augmented algebraic Riccati equation in which the quadratic term is nonnegative. A fixed-order compensator design problem is considered with partial information. System matrices in the problem are nonlinear functions of real valued parameters. >
Wave modulation: the geometry, kinematics, and dynamics of surface-wave packets

We examine the geometry, kinematics, and dynamics of weakly nonlinear narrow-banded deep-water wave packets governed by the modified nonlinear Schrodinger equation (Dysthe, Proc. R. Soc. Lond. A., vol. 369, 1979, pp. 105–114; MNLSE). A new derivation of the spatial MNLSE, by a direct application of Whitham’s method, elucidates its variational structure. Using this formalism, we derive a set of conserved quantities and moment evolution equations. Next, by examining the MNLSE in the limit of vanishing linear dispersion, analytic solutions can be found. These solutions then serve as trial functions, which when substituted into the moment evolution equations form a closed set of equations, allowing for a qualitative and quantitative examination of the MNLSE without resorting to numerically solving the full equation. To examine the theory we consider initially symmetric, chirped and unchirped wave packets, chosen to induce wave focusing and steepening. By employing the ansatz for the trial function discussed above, we predict, a priori, the evolution of the packet. It is found that the speed of wave packets governed by the MNLSE depends on their amplitude, and in particular wave groups speed up as they focus. Next, we characterize the asymmetric growth of the wave envelope, and explain the steepening of the forward face of the initially symmetric wave packet. As the packet focuses, its variance decreases, as does the chirp of the signal. These theoretical results are then compared with the numerical predictions of the MNLSE, and agreement for small values of fetch is found. Finally, we discuss the results in the context of existing theoretical, numerical and laboratory studies.
Generation of Long-Lived Bone Marrow Plasma Cells Secreting Antibodies Specific for the HIV-1 gp41 Membrane-Proximal External Region in the Absence of Polyreactivity.

UNLABELLED An effective preventive vaccine is highly sought after in order to stem the current HIV-1 pandemic. Both conservation of contiguous gp41 membrane-proximal external region (MPER) amino acid sequences across HIV-1 clades and the ability of anti-MPER broadly neutralizing antibodies (BNAbs) to block viral hemifusion/fusion establish the MPER as a prime vaccination target. In earlier studies, we described the development of an MPER vaccine formulation that takes advantage of liposomes to array the MPER on a lipid bilayer surface, paralleling its native configuration on the virus membrane while also incorporating molecular adjuvant and CD4 T cell epitope cargo. Here we demonstrate that several immunizations with MPER/liposomes induce high levels of bone marrow long-lived plasma cell (LLPC) antibody production. Single-cell immunoglobulin gene retrieval analysis shows that these plasma cells are derived from a germ line repertoire of B cells with a diverse representation of immunoglobulin genes, exhibiting antigen-driven positive selection. Characterization of LLPC recombinant monoclonal antibodies (rMAbs) indicates that antigen recognition is achieved through convergence on a common epitopic focus by utilizing various complementarity-determining region H3 (CDRH3) lengths. Importantly, the vast majority of rMAbs produced from these cells lack polyreactivity yet manifest antigen specificity in the context of lipids, shaping MPER-specific paratopes through selective pressure. Taken together, these findings demonstrate that the MPER is a vaccine target with minimal risk of generating off-target autoimmunity. IMPORTANCE A useful vaccine must generate desired long-term, antigen-specific antibody responses devoid of polyreactivity or autoreactivity. The common polyreactive features of some HIV-1 BNAbs have raised concern about elicitation of anti-MPER antibodies. Utilizing single-LLPC repertoire analysis and biophysical characterization of anti-MPER rMAbs, we show that their fine specificities require a structural fitness of the antibody combining site involving heavy and light chain variable domains shaped by somatic hypermutation and affinity maturation of B cells in the germinal center. Perhaps more importantly, our results demonstrate that the majority of MPER-specific antibodies are not inherently polyspecific and/or autoreactive, suggesting that polyreactivity of MPER-specific antibodies is separable from their antigen specificity.
Optimal healthcare decision making under multiple mathematical models: application in prostate cancer screening

Important decisions related to human health, such as screening strategies for cancer, need to be made without a satisfactory understanding of the underlying biological and other processes. Rather, they are often informed by mathematical models that approximate reality. Often multiple models have been made to study the same phenomenon, which may lead to conflicting decisions. It is natural to seek a decision making process that identifies decisions that all models find to be effective, and we propose such a framework in this work. We apply the framework in prostate cancer screening to identify prostate-specific antigen (PSA)-based strategies that perform well under all considered models. We use heuristic search to identify strategies that trade off between optimizing the average across all models’ assessments and being “conservative” by optimizing the most pessimistic model assessment. We identified three recently published mathematical models that can estimate quality-adjusted life expectancy (QALE) of PSA-based screening strategies and identified 64 strategies that trade off between maximizing the average and the most pessimistic model assessments. All prescribe PSA thresholds that increase with age, and 57 involve biennial screening. Strategies with higher assessments with the pessimistic model start screening later, stop screening earlier, and use higher PSA thresholds at earlier ages. The 64 strategies outperform 22 previously published expert-generated strategies. The 41 most “conservative” ones remained better than no screening with all models in extensive sensitivity analyses. We augment current comparative modeling approaches by identifying strategies that perform well under all models, for various degrees of decision makers’ conservativeness.
A marked correlation function for constraining modified gravity models

Future large scale structure surveys will provide increasingly tight constraints on our cosmological model. These surveys will report results on the distance scale and growth rate of perturbations through measurements of Baryon Acoustic Oscillations and Redshift-Space Distortions. It is interesting to ask: what further analyses should become routine, so as to test as-yet-unknown models of cosmic acceleration? Models which aim to explain the accelerated expansion rate of the Universe by modifications to General Relativity often invoke screening mechanisms which can imprint a non-standard density dependence on their predictions. This suggests density-dependent clustering as a `generic' constraint. This paper argues that a density-marked correlation function provides a density-dependent statistic which is easy to compute and report and requires minimal additional infrastructure beyond what is routinely available to such survey analyses. We give one realization of this idea and study it using low order perturbation theory. We encourage groups developing modified gravity theories to see whether such statistics provide discriminatory power for their models.
Operations of a shared, autonomous, electric vehicle fleet: Implications of vehicle & charging infrastructure decisions

Abstract There are natural synergies between shared autonomous vehicle (AV) fleets and electric vehicle (EV) technology, since fleets of AVs resolve the practical limitations of today’s non-autonomous EVs, including traveler range anxiety, access to charging infrastructure, and charging time management. Fleet-managed AVs relieve such concerns, managing range and charging activities based on real-time trip demand and established charging-station locations, as demonstrated in this paper. This work explores the management of a fleet of shared autonomous electric vehicles (SAEVs) in a regional, discrete-time, agent-based model. The simulation examines the operation of SAEVs under various vehicle range and charging infrastructure scenarios in a gridded city modeled roughly after the densities of Austin, Texas. Results based on 2009 NHTS trip distance and time-of-day distributions indicate that fleet size is sensitive to battery recharge time and vehicle range, with each 80-mile range SAEV replacing 3.7 privately owned vehicles and each 200-mile range SAEV replacing 5.5 privately owned vehicles, under Level II (240-volt AC) charging. With Level III 480-volt DC fast-charging infrastructure in place, these ratios rise to 5.4 vehicles for the 80-mile range SAEV and 6.8 vehicles for the 200-mile range SAEV. SAEVs can serve 96–98% of trip requests with average wait times between 7 and 10 minutes per trip. However, due to the need to travel while “empty” for charging and passenger pick-up, SAEV fleets are predicted to generate an additional 7.1–14.0% of travel miles. Financial analysis suggests that the combined cost of charging infrastructure, vehicle capital and maintenance, electricity, insurance, and registration for a fleet of SAEVs ranges from $0.42 to $0.49 per occupied mile traveled, which implies SAEV service can be offered at the equivalent per-mile cost of private vehicle ownership for low-mileage households, and thus be competitive with current manually-driven carsharing services and significantly cheaper than on-demand driver-operated transportation services. When Austin-specific trip patterns (with more concentrated trip origins and destinations) are introduced in a final case study, the simulation predicts a decrease in fleet “empty” vehicle-miles (down to 3–4% of all SAEV travel) and average wait times (ranging from 2 to 4 minutes per trip), with each SAEV replacing 5–9 privately owned vehicles.
Self-Fulfilling Debt Crises: A Quantitative Analysis

This paper investigates the role of self-fulfilling expectations in sovereign bond markets. We consider a model of sovereign borrowing featuring endogenous debt maturity, risk-averse lenders, and self-fulfilling crises a la Cole and Kehoe (2000). In this environment, interest rate spreads are driven by both fundamental and nonfundamental risk. These two sources of risk have contrasting implications for the maturity structure of debt chosen by the government. Therefore, they can be indirectly inferred by tracking the evolution of debt maturity. We fit the model to Italian data and find that nonfundamental risk played a limited role during the 2008–2012 crisis.
Thermal conductivity of GaAs/Ge nanostructures

Superlattices are of great interest as platform materials for thermoelectric technology that are capable of directly converting low-grade heat energy into useful electrical power. In this work, the thermal conductivities of GaAs/Ge superlattice nanostructures were investigated systematically in relation to their morphologies and interfaces. Thermal conductivities were measured using ultrafast time-domain thermoreflectance and were found to decrease with increasing interface densities, consistent with past understanding of microscopic phonon transport in the particle regime. The lowest thermal conductivities were observed in (GaAs)0.77(Ge2)0.23 alloys, and transmission electron microscopy study reveals phase separation in the alloys. These alloys can be interpreted as fine nanostructures, with length scales comparable to the periods of very thin superlattices. Electrical transport measurements along the film plane direction showed no significant reduction in electrical properties attributable to the interf...
The origin and expansion of regional value chains: the case of Kenyan horticulture

Regional value chains (RVCs), involving regional lead firms that trade within a single world region, are increasingly prominent within the Global South. Yet, emerging analyses of RVCs have not adequately interrogated how the expansion of RVCs relates to global value chains (GVCs), how actors in RVCs interact with overlapping chains, or the implications for development. Through a case study of horticulture value chains in Kenya, two main types of RVC–GVC interactions are identified. First, opportunistic RVCs emerged when suppliers found their produce rejected from GVCs for lack of standards compliance and began selling spillover produce in regional markets. Second, a more independent targeted RVC has evolved since suppliers began selling produce directly to regional supermarkets that had established their own regional procurement strategies and private standards. Some suppliers are also involved in hybrid interactions – participating in both opportunistic spillovers and targeted RVCs. The analysis concludes that the expansion of RVCs must be considered in the context of GVCs, leading to more nuanced understandings of the characteristics and development implications of RVCs.
Balancing Suspense and Surprise: Timely Decision Making with Endogenous Information Acquisition

We develop a Bayesian model for decision-making under time pressure with endogenous information acquisition. In our model, the decision-maker decides when to observe (costly) information by sampling an underlying continuous-time stochastic process (time series) that conveys information about the potential occurrence/non-occurrence of an adverse event which will terminate the decision-making process. In her attempt to predict the occurrence of the adverse event, the decision-maker follows a policy that determines when to acquire information from the time series (continuation), and when to stop acquiring information and make a final prediction (stopping). We show that the optimal policy has a "rendezvous" structure, i.e. a structure in which whenever a new information sample is gathered from the time series, the optimal "date" for acquiring the next sample becomes computable. The optimal interval between two information samples balances a trade-off between the decision maker’s "surprise", i.e. the drift in her posterior belief after observing new information, and "suspense", i.e. the probability that the adverse event occurs in the time interval between two information samples. Moreover, we characterize the continuation and stopping regions in the decision-maker’s state-space, and show that they depend not only on the decision-maker’s beliefs, but also on the "context", i.e. the current realization of the time series.
Heterogeneous wireless communication devices- present and future

Summary form only given. Convergence of communication and computing technologies is rapidly changing the requirement of wireless devices. While wireless wide area network (WWAN) based on cellular radios was evolving, a new set of wireless LAN networks which are fundamentally different from cellular networks emerged. Devices for applications in the wireless LAN networks (WLAN), wireless personal area networks (WPAN) and wireless metro area networks (WMAN) are being deployed in increasing numbers. Bluetooth and Ultra Wideband (UWB) technologies have been introduced for high-bandwidth wireless connectivity in personal area networks. Location identification technologies like GPS are getting integrated with wireless products as well. There is no doubt that tomorrowpsilas network environment will be extremely heterogeneous.
When Work Moves: Job Suburbanization and Black Employment

I provide novel evidence that job suburbanization has been an important cause of the decline in black employment since 1970, exploiting variation across US local labor markets. I rst present four stylized facts suggesting that any relationship between the two is driven by spatial frictions and not changes in labor demand or supply. I show that: (1) job suburbanization is not associated with signicant changes in the types of work performed; (2) suburbanization is driven by the location decisions of entrant rms rather than the spatial distribution of exiting rms; (3) these entrants locate in areas where blacks are ex-ante less likely to work than whites; (4) despite these shifts in the location of rms, black workers remain equally less likely to work in these suburban areas. I then show that job suburbanization is associated with substantial declines in black (relative) employment rates. Instrumenting for suburbanization using central city intersections with the interstate highway system yields similar estimates, corroborating a causal interpretation. Job suburbanization can explain the majority of the relative decline in black male employment over this period.
NOx-catalyzed partial oxidation of methane and ethane to formaldehyde by dioxygen

At 600 °C, NO x catalyzes the partial oxidation of both methane and ethane by dioxygen to form formaldehyde. The yield of oxygenates from methane is over 11. The yield increases to over 16 when 0.7% of ethane is added to the gas mixture. The yield of oxygenates from ethane is over 24. A catalytic cycle involving NO2 as the C–H activating species is proposed.