cssi/SciSciGPT-SciSciNet huggingface dataset:
Transport connectivity and health care access : evidence from Liberia

Health care access is an important policy concern, especially in rural areas. It is especially challenging in developing countries, where rural residents are poorer and less likely to be insured than those living in urban areas. Using the case of Liberia, this paper examines the effects of transport connectivity on health care access. The Ebola crisis in 2014 and 2015 clearly revealed the vulnerability of the country's transport and health systems to unexpected external shocks. Paying particular attention to the possible challenge of endogeneity associated with infrastructure investment, the study found that transport connectivity, especially greater road density, can increase access to health care, but there was no significant effect of road quality. This may be because of significantly skewed underlying data. The vast majority of roads in Liberia are in poor condition. The study also found that the statistical effect of road density varies depending on distance from a health facility. The effect is particularly significant within a 30- to 50-kilometer radius. Not only rural accessibility, but also broader transport connectivity needs to be developed to increase health care access.
Structure of the human volume regulated anion channel.

Every cell needs to regulate its internal volume or it will burst. Most of a cell’s volume is a watery mixture of salts, proteins and other molecules. A cell can take in more water from its surroundings, diluting this mixture and causing the cell to expand. If a cell starts to take up too much water, it will open channel proteins in its outer membrane called volume regulated anion channels (or VRACs for short). An open VRAC allows negatively charged ions to leave the cell, and in the process causes water to leave the cell too. This relieves the pressure inside the cell, and the cell starts to shrink. The structure of a VRAC is thought to contain six subunits, and most include at least two different kinds of subunit. Some of the subunits must be a protein called SWELL1 (which is also known as LRRC8A). The other subunits can be any of four similar proteins from the same protein family. Since a VRAC can contain additional subunits drawing from this pool of five proteins, many structures are possible. But it remains unclear exactly how the structure of a VRAC allows it to sense and regulate the volume of a cell. This is partly because scientists do not have enough information about the architecture of this protein to understand how it might work. Using electron microscopes, Kefauver et al. have now captured detailed images of a VRAC composed entirely of human SWELL1 proteins. The overall structure of VRAC resembles a six-legged jellyfish, with a pore on the cell’s exterior passing through a constricted dome followed by three pairs of arms that extend into the cell’s interior. Given the observed structure, Kefauver et al. speculate that the arms of the SWELL1 proteins sense salt concentrations within the cell (to tell if its become diluted by an influx of water) and then interact with the rest of the channel. In response to these interactions, the domed part of the VRAC constricts or dilates to help regulate the cell’s volume. Molecular biologists can now use these structural details to further study the fundamentals behind how cells regulate their volume. This model will also improve scientific understanding of how diverse VRAC structures differ in their responses to changes in pressure within cells.
Travel Time Tomography With Adaptive Dictionaries

We develop a two-dimensional travel time tomography method, which regularizes the inversion by modeling groups of slowness pixels from discrete slowness maps, called patches, as sparse linear combinations of atoms from a dictionary. We propose to use dictionary learning during the inversion to adapt dictionaries to specific slowness maps. This patch regularization, called the local model, is integrated into the overall slowness map, called the global model. The local model considers small-scale variations using a sparsity constraint, and the global model considers larger-scale features constrained using $\ell _2$ regularization. This strategy in a locally sparse travel time tomography (LST) approach enables simultaneous modeling of smooth and discontinuous slowness features. This is in contrast to conventional tomography methods, which constrain models to be exclusively smooth or discontinuous. We develop a maximum a posteriori formulation for LST and exploit the sparsity of slowness patches using dictionary learning. The LST approach compares favorably with smoothness and total variation regularization methods on densely, but irregularly sampled synthetic slowness maps.
The Average and Heterogeneous Effects of Transportation Investments: Evidence from Sub-Saharan Africa 1960-2010

Previous work on transportation investments has focused on average impacts in high- and middle-income countries. We estimate average and heterogeneous effects in a poor continent, Africa, using roads and cities data spanning 50 years in 39 countries. Using changes in market access due to distant road construction as a source of exogenous variation, we estimate an 30-year elasticity of city population with respect to market access of 0.05-0.20. Our results suggest that this elasticity is stronger for small and remote cities, and weaker in politically favored and agriculturally suitable areas. Access to foreign cities matters little.
Centrality Measures for Graphons: Accounting for Uncertainty in Networks

As relational datasets modeled as graphs keep increasing in size and their data-acquisition is permeated by uncertainty, graph-based analysis techniques can become computationally and conceptually challenging. In particular, node centrality measures rely on the assumption that the graph is perfectly known – a premise not necessarily fulfilled for large, uncertain networks. Accordingly, centrality measures may fail to faithfully extract the importance of nodes in the presence of uncertainty. To mitigate these problems, we suggest a statistical approach based on graphon theory: we introduce formal definitions of centrality measures for graphons and establish their connections to classical graph centrality measures. A key advantage of this approach is that centrality measures defined at the modeling level of graphons are inherently robust to stochastic variations of specific graph realizations. Using the theory of linear integral operators, we define degree, eigenvector, Katz and PageRank centrality functions for graphons and establish concentration inequalities demonstrating that graphon centrality functions arise naturally as limits of their counterparts defined on sequences of graphs of increasing size. The same concentration inequalities also provide high-probability bounds between the graphon centrality functions and the centrality measures on any sampled graph, thereby establishing a measure of uncertainty of the measured centrality score.
Discovering flaws in security-focused static analysis tools for android using systematic mutation

Mobile application security has been one of the major areas of security research in the last decade. Numerous application analysis tools have been proposed in response to malicious, curious, or vulnerable apps. However, existing tools, and specifically, static analysis tools, trade soundness of the analysis for precision and performance, and are hence soundy. Unfortunately, the specific unsound choices or flaws in the design of these tools are often not known or well-documented, leading to a misplaced confidence among researchers, developers, and users. This paper proposes the Mutation-based soundness evaluation (µSE) framework, which systematically evaluates Android static analysis tools to discover, document, and fix, flaws, by leveraging the well-founded practice of mutation analysis. We implement µSE as a semi-automated framework, and apply it to a set of prominent Android static analysis tools that detect private data leaks in apps. As the result of an in-depth analysis of one of the major tools, we discover 13 undocumented flaws. More importantly, we discover that all 13 flaws propagate to tools that inherit the flawed tool. We successfully fix one of the flaws in cooperation with the tool developers. Our results motivate the urgent need for systematic discovery and documentation of unsound choices in soundy tools, and demonstrate the opportunities in leveraging mutation testing in achieving this goal.
Restructuring endpoint congestion control

This paper describes the implementation and evaluation of a system to implement complex congestion control functions by placing them in a separate agent outside the datapath. Each datapath---such as the Linux kernel TCP, UDP-based QUIC, or kernel-bypass transports like mTCP-on-DPDK---summarizes information about packet round-trip times, receptions, losses, and ECN via a well-defined interface to algorithms running in the off-datapath Congestion Control Plane (CCP). The algorithms use this information to control the datapath's congestion window or pacing rate. Algorithms written in CCP can run on multiple datapaths. CCP improves both the pace of development and ease of maintenance of congestion control algorithms by providing better, modular abstractions, and supports aggregation capabilities of the Congestion Manager, all with one-time changes to datapaths. CCP also enables new capabilities, such as Copa in Linux TCP, several algorithms running on QUIC and mTCP/DPDK, and the use of signal processing algorithms to detect whether cross-traffic is ACK-clocked. Experiments with our user-level Linux CCP implementation show that CCP algorithms behave similarly to kernel algorithms, and incur modest CPU overhead of a few percent.
Extracellular vesicles transfer nuclear Abl-dependent and radiation-induced miR-34c into unirradiated cells to cause bystander effects

Ionizing radiation (IR) not only activates DNA damage response (DDR) in irradiated cells but also induces bystander effects (BE) in cells not directly targeted by radiation. How DDR pathways activated in irradiated cells stimulate BE is not well understood. We show here that extracellular vesicles secreted by irradiated cells (EV-IR), but not those from unirradiated controls (EV-C), inhibit colony formation in unirradiated cells by inducing reactive oxygen species (ROS). We found that µEV-IR from Abl nuclear localization signal-mutated ( Abl-µNLS) cells could not induce ROS, but expression of wild-type Abl restored that activity. Because nuclear Abl stimulates miR-34c biogenesis, we measured miR-34c in EV and found that its levels correlated with the ROS-inducing activity of EV. We then showed that EV from miR-34c minigene-transfected, but unirradiated cells induced ROS; and transfection with miR-34c-mimic, without radiation or EV addition, also induced ROS. Furthermore, EV-IR from miR34-family triple-knockout cells could not induce ROS, whereas EV-IR from wild-type cells could cause miR-34c increase and ROS induction in the miR-34 triple-knockout cells. These results establish a novel role for extracellular vesicles in transferring nuclear Abl-dependent and radiation-induced miR-34c into unirradiated cells to cause bystander oxidative stress.
Catastrophizing, pain, and functional outcomes for children with chronic pain: a meta-analytic review

Pediatric chronic pain is associated with numerous negative outcomes including increased physical disability, increased rates of depression and anxiety, and decreased quality of life (QOL). Pain catastrophizing-broadly conceptualized as including rumination, magnification, and helplessness cognitions surrounding one's pain-has been linked with poor functional outcomes in children with chronic pain. Pain catastrophizing in pediatric chronic pain is often considered a key factor on which to focus treatment efforts. However, absent a systematic review that integrates the relevant literature, this call for routine assessment and targeted treatment may be premature. This study aimed to: (1) meta-analytically quantify the relationship between catastrophizing and pain and functional/psychosocial outcomes (functional disability/physical functioning, anxiety, depression, and QOL) in children with chronic pain, and (2) examine potential moderators of these relationships. Using a random-effects model, a total of 111 effect sizes from 38 studies were analyzed. Effect sizes ranged from medium to large, with anxiety, depression, and QOL demonstrating a strong association with catastrophizing. Pain intensity and physical disability had a moderate association with catastrophizing. These relationships were robust, minimizing potential publication bias. None of the examined moderators were significant. The strong relationships found between catastrophizing and anxiety, depression, and QOL suggest that successfully intervening on catastrophizing could have far reaching implications in improving pain outcomes in pediatric chronic pain.
Convergence of Langevin MCMC in KL-divergence

Langevin diffusion is a commonly used tool for sampling from a given distribution. In this work, we establish that when the target density $p^*$ is such that $\log p^*$ is $L$ smooth and $m$ strongly convex, discrete Langevin diffusion produces a distribution $p$ with $KL(p||p^*)\leq \epsilon$ in $\tilde{O}(\frac{d}{\epsilon})$ steps, where $d$ is the dimension of the sample space. We also study the convergence rate when the strong-convexity assumption is absent. By considering the Langevin diffusion as a gradient flow in the space of probability distributions, we obtain an elegant analysis that applies to the stronger property of convergence in KL-divergence and gives a conceptually simpler proof of the best-known convergence results in weaker metrics.
Nonlinear analog networks for image smoothing and segmentation

Image smoothing and segmentation algorithms are frequently formulated as optimization problems. Linear and nonlinear (reciprocal) resistive networks have solutions characterized by an extremum principle. Thus, appropriately designed networks can automatically solve certain smoothing and segmentation problems in robot vision. This paper considers switched linear resistive networks and nonlinear resistive networks for such tasks. The latter network type is derived from the former via an intermediate stochastic formulation, and a new result relating the solution sets of the two is given for the ``zero termperature'''' limit. We then present simulation studies of several continuation methods that can be gracefully implemented in analog VLSI and that seem to give ``good'''' results for these non-convex optimization problems.
The impacts of workers' remittances on human capital and labor supply in developing countries

Abstract This study investigates the impacts of workers' remittances on human capital and labor supply by using data for 122 developing countries from 1990 to 2015. This topic has not been explored thoroughly at the aggregate level, mainly due to endogeneity of remittances and the difficulty in finding instruments to resolve this issue. To address the endogeneity of remittances, I estimate bilateral remittances and use them to create weighted indicators of remittance-sending countries. These weighted indicators are used as instruments for remittance inflow to remittance-receiving countries. Results obtained in this study indicate that remittances raise per capita health expenditures and reduce undernourishment prevalence, depth of food deficit, prevalence of stunting, and child mortality rate. Remittances also raise school enrollment, school completion rate, and private school enrollment. Although there is no difference in the impact of remittances on the health outcome of boys and girls, remittances improve the educational outcome of girls more than the educational outcome of boys. Further, remittances decrease the female labor force participation rate but do not affect the male labor force participation rate.
Mitigating Location Privacy Attacks on Mobile Devices using Dynamic App Sandboxing

We present the design, implementation and evaluation of a system, called MATRIX, developed to protect the privacy of mobile device users from location inference and sensor side-channel attacks. MATRIX gives users control and visibility over location and sensor (e.g., Accelerometers and Gyroscopes) accesses by mobile apps. It implements a PrivoScope service that audits all location and sensor accesses by apps on the device and generates real-time notifications and graphs for visualizing these accesses; and a Synthetic Location service to enable users to provide obfuscated or synthetic location trajectories or sensor traces to apps they find useful, but do not trust with their private information. The services are designed to be extensible and easy for users, hiding all of the underlying complexity from them. MATRIX also implements a Location Provider component that generates realistic privacy-preserving synthetic identities and trajectories for users by incorporating traffic information using historical data from Google Maps Directions API, and accelerations using statistical information from user driving experiments. The random traffic patterns are generated by modeling/solving user schedule using a randomized linear program and modeling/solving for user driving behavior using a quadratic program. We extensively evaluated MATRIX using user studies, popular location-driven apps and machine learning techniques, and demonstrate that it is portable to most Android devices globally, is reliable, has low-overhead, and generates synthetic trajectories that are difficult to differentiate from real mobility trajectories by an adversary.
Highly Contiguous Genome Assemblies of 15 Drosophila Species Generated Using Nanopore Sequencing

The Drosophila genus is a unique group containing a wide range of species that occupy diverse ecosystems. In addition to the most widely studied species, Drosophila melanogaster, many other members in this genus also possess a well-developed set of genetic tools. Indeed, high-quality genomes exist for several species within the genus, facilitating studies of the function and evolution of cis-regulatory regions and proteins by allowing comparisons across at least 50 million years of evolution. Yet, the available genomes still fail to capture much of the substantial genetic diversity within the Drosophila genus. We have therefore tested protocols to rapidly and inexpensively sequence and assemble the genome from any Drosophila species using single-molecule sequencing technology from Oxford Nanopore. Here, we use this technology to present highly contiguous genome assemblies of 15 Drosophila species: 10 of the 12 originally sequenced Drosophila species (ananassae, erecta, mojavensis, persimilis, pseudoobscura, sechellia, simulans, virilis, willistoni, and yakuba), four additional species that had previously reported assemblies (biarmipes, bipectinata, eugracilis, and mauritiana), and one novel assembly (triauraria). Genomes were generated from an average of 29x depth-of-coverage data that after assembly resulted in an average contig N50 of 4.4 Mb. Subsequent alignment of contigs from the published reference genomes demonstrates that our assemblies could be used to close over 60% of the gaps present in the currently published reference genomes. Importantly, the materials and reagents cost for each genome was approximately $1,000 (USD). This study demonstrates the power and cost-effectiveness of long-read sequencing for genome assembly in Drosophila and provides a framework for the affordable sequencing and assembly of additional Drosophila genomes.
Double-excitation manifold's effect on exciton transfer dynamics and the efficiency of coherent light harvesting.

The efficiency of natural light harvesting systems is largely determined by their ability to transfer excitations from the antenna to the energy trapping center before recombination. The exciton diffusion length similarly limits organic photovoltaics and demands bulk heterojunction architectures. Dark state protection, achieved by coherent coupling between subunits within the antenna, can significantly reduce radiative recombination and enhance the efficiency of energy trapping. In this work we extend the dark state concept to the double-excitation manifold by studying the dynamical flow of excitations. We show that the lowest double-excitation state carries minimal oscillator strength, but relaxation to this state from higher lying double excitations can be relatively rapid such that the lowest double excitation state can act as a dynamical dark state protecting excitation from radiative recombination. This mechanism is sensitive to topology and operates differently for chain and ring structures, while becoming more pronounced in both geometries when the size of the antenna increases. When the exciton–exciton annihilation (EEA) mechanism is considered, the double-excitation population is quickly depleted and the dynamics change dramatically. However the efficiency and output power are still significantly different from those calculated using the single-excitation manifold alone, justifying the necessity of considering the double-excitation manifold. Remarkably, in certain scenarios, EEA can even increase the overall light harvesting efficiency by bringing population down from the double-excitation dark states to the single-excitation manifold.
Importance Weighting and Variational Inference

Recent work used importance sampling ideas for better variational bounds on likelihoods. We clarify the applicability of these ideas to pure probabilistic inference, by showing the resulting Importance Weighted Variational Inference (IWVI) technique is an instance of augmented variational inference, thus identifying the looseness in previous work. Experiments confirm IWVI's practicality for probabilistic inference. As a second contribution, we investigate inference with elliptical distributions, which improves accuracy in low dimensions, and convergence in high dimensions.
Longitudinal algebra prediction for early versus later takers

Algebra I is a crucial course for middle and high school students for successful STEM-related coursework. A key issue is whether students should take Algebra I in Grade 8 versus Grade 9. Large-scal...
Investment and financing in incomplete markets

I propose a model of production with incomplete financial markets, in which a firm can act as a financial innovator by issuing claims against its stock. In this environment, market value maximization may be against the firm’s shareholders’ interests. I propose instead a new measure of adjusted value, which is the sum between the market value and the shareholders’ surplus from their trades in the stock market. If a firm maximizes its adjusted value, then its financial policy is relevant (that is, Modigliani–Miller theorem does not hold), equilibrium outcomes are stable to shareholders’ renegotiation, and endogenously incomplete markets can arise at the equilibrium. If the firm is competitive, the adjusted value coincides with the objective proposed by Grossman and Hart (Econometrica 47(2):293–329, 1979). In a competitive market with no production-specific uninsurable risk (that is, spanning property holds), the adjusted value coincides with the market value.
'The Perfect One': Understanding Communication Practices and Challenges with Animated GIFs

Animated GIFs are increasingly popular in text-based communication. Finding the perfect GIF can make conversations funny, interesting, and engaging, but GIFs also introduce potentials for miscommunication. Through 24 in-depth qualitative interviews, this empirical, exploratory study examines the nuances of communication practices with animated GIFs to better understand why and how GIFs can send unintentional messages. We find participants leverage contexts like source material and interpersonal relationship to find the perfect GIFs for different communication scenarios, while these contexts are also the primary reason for miscommunication and some technical usability issues. This paper concludes with a discussion of the important role that different types of context play in the use and interpretations of GIFs, and argues that nonverbal communication tools should account for complex contexts and common ground that communication media rely on.
A Routing Approach to Reduce Glitches in Low Power FPGAs

This paper presents a novel approach to reduce dynamic power in field-programmable gate arrays (FPGAs) by reducing glitches during routing. It finds alternative routes for early-arriving signals so that signal arrival times at look-up tables are aligned. We developed an efficient algorithm to find routes with target delays and then built a glitch-aware router aiming at reducing dynamic power. To the best of our knowledge, this is the first glitch-aware routing algorithm for FPGAs. Experiments show that an average of 27% reduction in glitch power is achieved, which translates into an 11% reduction in dynamic power, compared to the glitch-unaware versatile place and route's router.
Proceedings of the first ACM international workshop on Mobile entity localization and tracking in GPS-less environments

It is our great pleasure to welcome you to the 1st ACM International Workshop on Mobile Entity Localization and Tracking in GPS-less Environments -- MELT'08. Location-awareness is a key component for achieving context-awareness. Recent years have witnessed an increasing trend of location-based services and applications. In most cases, however, location information is limited by the accessibility to GPS, which is unavailable for indoor or underground facilities and unreliable in urban environments. Much research has been done, in both the sensor network community and the ubiquitous computing community, to provide techniques for localization and tracking in GPS-less environments. Novel applications based on ad-hoc localization and real-time tracking of mobile entities are growing as a result of these technologies. It is time to bring leaders from both the academic and industrial research communities to discuss challenging and open problems, to evaluate pros and cons of various approaches, to bridge the gap between theory and applications, and to envision new research opportunities in MELT. The call for papers attracted 38 submissions from Asia, Canada, Europe, and the United States. The program committee accepted 14 papers for oral presentations and 9 papers for poster presentations. The workshop consists of four technical sessions and three poster sessions, with topics covering areas of optimization and signal processing techniques, novel radio signal strength based methods, as well as systems and applications in MELT.
Improving proteinuria screening with mailed smartphone urinalysis testing in previously unscreened patients with hypertension: a randomized controlled trial

Proteinuria screening is recommended for patients with hypertension to screen for kidney disease and identify those at elevated risk for cardiovascular disease. However, screening rates among hypertensive patients are low. Home testing strategies may be useful in improving proteinuria screening adherence. We conducted an individual-level, randomized trial at 55 primary care clinic sites in the Geisinger Health System to evaluate the effectiveness of a strategy using home smartphone urinalysis test (Dip.io) to complete proteinuria screening in previously unscreened non-diabetic patient portal users with hypertension. All patients received an educational letter and a standing urinalysis lab order, and then were randomized to control (usual care) or intervention. Intervention arm participants were invited to complete proteinuria screening with a mailed home smartphone urinalysis test. Co-primary outcomes were completion of proteinuria screening and number of albuminuria cases (albumin/creatinine ratio [ACR] ≥ 30 mg/g or protein/creatinine ratio ≥ 150 mg/g) at the end of 3 months. We also evaluated patient satisfaction with the home test, and compliance with recommendations for patients with newly detected albuminuria. A total of 999 patients were randomized to intervention or control. Out of 499 patients assigned to the intervention arm, 253 were reached by phone, and 69/97 (71.1%) consented patients completed the home test. Overall, the intervention increased proteinuria screening completion (28.9% vs. 18.0%; p < 0.001) with no effect on the number of albuminuria cases (4 vs. 4) although only 6/57 (10.5%) patients with trace or 1+ urine dipstick protein had a follow-up quantitative test. Among the 55 patients who completed a survey after the home test, 89% preferred testing at home rather than the physician’s office. A strategy using a home urinalysis smartphone test increased proteinuria screening rates in previously unscreened patients with hypertension and may be useful in increasing rates of proteinuria screening compliance. Future studies should evaluate use of home testing kits to screen for and confirm albuminuria, and determine whether improving early detection of kidney disease can improve future kidney health. Clinical Trial Registry: NCT03470701 (First posted 3/20/2018) https://clinicaltrials.gov/ct2/show/NCT03470701 . This study was retrospectively registered.
Chapter 6 – Postclosing Integration: Mergers, Acquisitions, and Business Alliances

The integration phase is an important contributor to the ultimate success of the merger or acquisition, and ineffective integration is commonly given as one of the primary reasons mergers and acquisitions (M&As) sometimes fail to meet expectations. This chapter outlines a practical process for realizing successful integration. The critical success factors include careful premerger planning, candid and continuous communication, adopting the right pace for combining the businesses, appointing an integration manager and team with clearly defined goals and lines of authority, and making the difficult decisions early in the process. This chapter concludes with a discussion of how to overcome some of the unique obstacles encountered in integrating business alliances.
Surgical correction of hallux valgus

Surgical treatment of hallux valgus was carried out by a procedure which comprises lengthening of extensor tendons, interposition of a capsular flap, and attachment of the periosteocapsular cover with distributed tension in addition to the routine excision of a sufficiently large portion of the first phalanx and metatarsal head. Impairment of function and persistent pain were considered more important in the indication for operation of hallux valgus than the cosmetic demands. Of 142 patients operated upon, 117 patients displayed a satisfactory result applying morphologic and functional criteria.
Competition and Appraisal Inflation

In mortgage debt contracts, real property serves as collateral and the terms of mortgage financing are largely conditional on the certification of collateral value by appraisers. However, overstatement of collateral value is common in the appraisal industry, causing troubles in the mortgage market as observed in the recent crisis. In this paper, we examine whether competition in the appraisal industry affects appraisal bias. We model appraiser behavior given a loan officer’s preference for favorable appraisals (i.e. appraisal values at least as high as the transaction prices). As appraisers cater to loan officers to increase their probability of winning future business, our model predicts more inflated appraisals in more competitive markets. We confirm this prediction using a sample of purchase mortgages originated between 2003-2006 by a large subprime mortgage lender. Our results show that a one standard deviation increase in appraiser competition, measured at the MSA/year level, is associated with a 1.6–3.7 percentage point increase in the share of at-price appraisals. Furthermore, the effect is stronger in areas experiencing high house price growth.
On Equilibrium When Contingent Capital Has a Market Trigger: A Correction to Sundaresan and Wang Journal of Finance (2015)

This paper identifies an error in Sundaresan and Wang (2015, hereafter SW) that invalidates its Theorem 1. The paper develops a model of contingent capital (CC) with a stock price trigger that is consistent with SW's framework and yields closed‐form solutions for stock and CC prices. Yet, the model shows that unique stock price equilibria exist for a broader range of CC contractual terms than those required by SW. Specifically, when conversion terms benefit CC investors and penalize shareholders, a unique equilibrium can exist rather than the multiple equilibria stated in SW.
Environmental Feedback Drives Multiple Behaviors from the Same Neural Circuit

The ability of a single neural circuit to produce qualitatively distinct behaviors is typically attributed to some adaptive mechanism in the circuit itself. However, neural circuits are also embedded in particular bodies and environments, and feedback through the sensorimotor loop may also serve to drive behavioral differentiation. Here we explore the ability of a single neural circuit to produce qualitatively different behaviors based on changing patterns of environmental feedback. Agents equipped with two sets of effectors and controlled by fixed neural circuits are evolved to catch circles under three different motor conditions. In one condition, the agent must coordinate both sets of effectors, while in each of the other conditions one set of effectors is lesioned and the agent must rely on the other set alone to accomplish the task. A detailed behavioral analysis of the best evolved agent is reported, providing numerous insights into its evolved behavioral mechanism. The agent is found to produce significantly different motor outputs in each of the three conditions, to rely on continuous environmental feedback for successful behavior, and to switch flexibly between different behavioral conditions.
Stronger L2/L2 compressed sensing; without iterating

We consider the extensively studied problem of l2/l2 compressed sensing. The main contribution of our work is an improvement over [Gilbert, Li, Porat and Strauss, STOC 2010] with faster decoding time and significantly smaller column sparsity, answering two open questions of the aforementioned work. Previous work on sublinear-time compressed sensing employed an iterative procedure, recovering the heavy coordinates in phases. We completely depart from that framework, and give the first sublinear-time l2/l2 scheme which achieves the optimal number of measurements without iterating; this new approach is the key step to our progress. Towards that, we satisfy the l2/l2 guarantee by exploiting the heaviness of coordinates in a way that was not exploited in previous work. Via our techniques we obtain improved results for various sparse recovery tasks, and indicate possible further applications to problems in the field, to which the aforementioned iterative procedure creates significant obstructions.
In-solution enrichment identifies peptide inhibitors of protein-protein interactions.

The use of competitive inhibitors to disrupt protein–protein interactions (PPIs) holds great promise for the treatment of disease. However, the discovery of high-affinity inhibitors can be a challenge. Here we report a platform for improving the affinity of peptide-based PPI inhibitors using non-canonical amino acids. The platform utilizes size exclusion-based enrichment from pools of synthetic peptides (1.5–4 kDa) and liquid chromatography-tandem mass spectrometry-based peptide sequencing to identify high-affinity binders to protein targets, without the need for ‘reporter’ or ‘encoding’ tags. Using this approach—which is inherently selective for high-affinity binders—we realized gains in affinity of up to ~100- or ~30-fold for binders to the oncogenic ubiquitin ligase MDM2 or HIV capsid protein C-terminal domain, which inhibit MDM2–p53 interaction or HIV capsid protein C-terminal domain dimerization, respectively. Subsequent macrocyclization of select MDM2 inhibitors rendered them cell permeable and cytotoxic toward cancer cells, demonstrating the utility of the identified compounds as functional PPI inhibitors. Affinity-based selection in solution enables the identification of high-affinity ligands for disrupting the MDM2–p53 interaction and binding to the HIV capsid protein from libraries of both linear and cyclic peptides containing non-canonical amino acids.
Admission Control Biases in Hospital Unit Capacity Management: How Occupancy Information Hurdles and Decision Noise Impact Utilization

Providing patients with timely care from the appropriate unit involves both correct clinical evaluation of patient needs and making admission decisions to effectively manage a unit with limited cap...
The Value of Proximity to a Vacation Home Rental in a Resort Community

Based upon a hedonic regression analysis of home sales in the City of South Lake Tahoe (CA), a vacation home rental (VHR) sells for more than a similar non-VHR. In addition, the presence of VHRs wi...
Digital Segregation: Gender, Occupation, and Access to Politics:

In the United States, women often show less interest in politics, and under some conditions, perform worse than men on political knowledge tests. In an age where education levels have reached parit...
Baryogenesis and the new cosmology

I begin this talk with a brief review of the status of approaches to understanding the origin of the baryon asymmetry of the Universe (BAU). I then describe a recent model unifying three seemingly distinct problems facing particle cosmology: the origin of inflation, the generation of the BAU and the nature of dark energy.
Bleeding, cramping, and satisfaction among new copper IUD users: A prospective study.

OBJECTIVE We assess change in bleeding, cramping, and IUD satisfaction among new copper (Cu) IUD users during the first six months of use, and evaluate the impact of bleeding and cramping on method satisfaction. METHODS We recruited 77 women ages 18-45 for this prospective longitudinal observational cohort study. Eligible women reported regular menses, had no exposure to hormonal contraception in the last three months, and desired a Cu IUD for contraception. We collected data prospectively for 180 days following IUD insertion. Monthly, participants reported bleeding scores using the validated pictorial blood loss assessment chart (PBAC), IUD satisfaction using a five-point Likert scale, and cramping using a six-level ordinal scale. We used multiple imputation to address nonrandom attrition. Structural equation models for count and ordered outcomes were used to model bleeding, cramping, and IUD satisfaction growth curves over the six monthly repeated assessments. RESULTS Bleeding significantly decreased (approximately 23%) over the course of the study from an estimated PBAC = 195 at one month post-insertion to PBAC = 151 at six months (t = -2.38, p<0.05). Additionally, IUD satisfaction improved over time (t = 2.65, p<0.01), increasing from between "Neutral" and "Satisfied" to "Satisfied" over the six month study. Cramping decreased notably over the six month study from between biweekly and weekly, to once or twice a month (t = -4.38, p<0.001). Finally, bleeding, but not cramping, was associated with IUD satisfaction across the study (t = -2.31, p<0.05) and at study end (t = -2.81, p<0.01). CONCLUSIONS New Cu IUD users reported decreasing bleeding and cramping, and increasing IUD satisfaction, over the first six months. Method satisfaction was negatively associated with bleeding.
Synthesis of jenamidines A1/A2.

Addition of the enolate of tert-butyl acetate to cyanamide methyl ester 17 followed by treatment with LHMDS afforded vinylogous urea 19 in 27% yield. Vinylogous urea 19 was also obtained from 37 and tert-butyl cyanoacetate in 50% yield. Acylation of 19 with acid chloride 31d, followed by hydrolysis of the tert-butyl ester and decarboxylation with 9:1 CH2Cl2/TFA and very mild basic hydrolysis of the methoxyacetate ester, afforded jenamidines A1/A2 (3) in 45% yield. This first synthesis confirms our reassignment of the jenamidines A1/A2 structure.
Solid-state photoluminescence sensitization of Tb3+ by novel Au2Pt2 and Au2Pt4 cyanide clusters.

The syntheses are reported for two novel Tb3+ heterotrimetallic cyanometallates, K2[Tb(H2O)4(Pt(CN)4)2]Au(CN)2·2H2O (1) and [Tb(C10N2H8)(H2O)4(Pt(CN)4)(Au(CN)2)]·1.5C10N2H8·2H2O (2) (C10N2H8 = 2,2′-bipyridine). Both compounds have been isolated as colorless crystals, and single-crystal X-ray diffraction has been used to investigate their structural features. Crystallographic data (MoKα, λ = 0.71073 A, T = 290 K): 1, tetragonal, space group P42/nnm, a = 11.9706(2) A, c = 17.8224(3) A, V = 2553.85(7) A3, Z = 4; 2, triclinic, space group P1, a = 10.0646(2) A, b = 10.7649(2) A, c = 17.6655(3) A, α = 101.410(2)°, β = 92.067(2)°, γ = 91.196(2)°, V = 1874.14(6) A3, Z = 2. For the case of 1, the structure contains Au2Pt4 hexameric noble metal clusters, while 2 includes Au2Pt2 tetrameric clusters. The clusters are alike in that they contain Au−Au and Au−Pt, but not Pt−Pt, metallophilic interactions. Also, the discrete clusters are directly coordinated to Tb3+ and sensitize its emission in both solid-state compoun...
Synthesis and analysis of the sterically constrained l-glutamine analogues (3S,4R)-3,4-dimethyl-l-glutamine and (3S,4R)-3,4-dimethyl-l-pyroglutamic acid

Abstract The nonproteinogenic amino acids (3 S ,4 R )-3,4-dimethyl- l -pyroglutamic acid and (3 S ,4 R )-3,4-dimethyl- l -glutamine—found in the cyclic depsipeptides callipeltin B, callipeltin A, and papuamide A—were synthesized from a common intermediate derived from l -pyroglutamic acid. The diastereoselective introduction of the methyl groups was accomplished by cuprate addition and enolate alkylation, followed by a kinetic epimerization of the C-4 methyl substituent. (3 S ,4 R )-3,4-Dimethyl- l -glutamine shows a conformational restriction of its side chain which may be related to its biological function in the natural products where it is found.
Determinants of Base-Pair Substitution Patterns Revealed by Whole-Genome Sequencing of DNA Mismatch Repair Defective Escherichia coli

Mismatch repair (MMR) is a major contributor to replication fidelity, but its impact varies with sequence context and the nature of the mismatch. Mutation accumulation experiments followed by whole-genome sequencing of MMR-defective Escherichia coli strains yielded ≈30,000 base-pair substitutions (BPSs), revealing mutational patterns across the entire chromosome. The BPS spectrum was dominated by A:T to G:C transitions, which occurred predominantly at the center base of 5′NAC3′+5′GTN3′ triplets. Surprisingly, growth on minimal medium or at low temperature attenuated these mutations. Mononucleotide runs were also hotspots for BPSs, and the rate at which these occurred increased with run length. Comparison with ≈2000 BPSs accumulated in MMR-proficient strains revealed that both kinds of hotspots appeared in the wild-type spectrum and so are likely to be sites of frequent replication errors. In MMR-defective strains transitions were strand biased, occurring twice as often when A and C rather than T and G were on the lagging-strand template. Loss of nucleotide diphosphate kinase increases the cellular concentration of dCTP, which resulted in increased rates of mutations due to misinsertion of C opposite A and T. In an mmr ndk double mutant strain, these mutations were more frequent when the template A and T were on the leading strand, suggesting that lagging-strand synthesis was more error-prone, or less well corrected by proofreading, than was leading strand synthesis.
π-Facial Diastereoselection in the 1,2-Addition of Allylmetal Reagents to 2-Methoxycyclohexanone and Tetrahydrofuranspiro-(2-cyclohexanone)

The stereochemical course of the 1,2-addition of several allylmetal reagents and of the Normant Grignard [ClMgO(CH2)3MgCl] to 2-methoxycyclohexanone and tetrahydrofuranspiro-(2-cyclohexanone) has been determined. In four of the six substrates examined, a 4-tert-butyl group is present to serve as a conformational anchor. The neighboring methoxyl substituent is shown to be capable of engaging effectively in chelation, although special circumstances can dictate otherwise. Experiments involving the allylindium reagent as the nucleophile in aqueous solution reveal that the presence of water does not inhibit the operation of chelation control, which often exceeds that attainable with the corresponding magnesium, cerium, and chromium reagents in anhydrous media by significant margins. The extent to which cooperation between the α-oxygen atom and control of π-facial nucleophilic attack reaches a maximum (>97:3) is when the system is conformationally rigid and the 2-methoxy and 4-tert-butyl groups are both oriente...
Ammonothermal conversion of cyclotrigallazane to GaN: Synthesis of nanocrystalline and cubic GaN from [H2GaNH2]3

Under ammonothermal conditions, cyclotrigallazane, [H2GaNH2]3, was converted to nanocrystalline GaN. The coherent length of the GaN product could be controlled by manipulating reaction time and temperature. Nanocrystalline GaN powders with average crystallite sizes of 3−17 nm were produced in the temperature range of 150−450 °C. Analysis of the powders by XRD and TEM indicated that the nanocrystals possessed a structure composed of a random arrangement of cubic and hexagonal close packed planes. The addition of NH4I to the reaction mixture resulted in the isolation of bulk samples of phase pure, cubic GaN at temperatures as low as 200 °C. The synthesis of the cubic phase was found to be temperature dependent, with mixtures of cubic and hexagonal GaN being produced at temperatures greater than 350 °C.
One-Pot in Situ Formation and Reaction of Trimethyl(trichloromethyl)silane: Application to the Synthesis of 2,2,2-Trichloromethylcarbinols

2,2,2-Trichloromethylcarbinols are 1 are valuable synthetic intermediates with a multitude of uses. A scalable procedure for the synthesis of TMS-protected-2,2,2-trichloromethylcarbinols and 2,2,2-trichloromethylcarbinols 1 was developed that employs the in situ generation and reaction of trimethyl(trichloromethyl)silane (CCl(3)-TMS). The procedure avoids the exposure of the carbonyl compounds to the strongly basic conditions typically used for this transformation and also avoids isolation of the difficult-to-handle CCl(3)-TMS. This procedure was applied to diastereoselective trichloromethyl additions to 2-substituted 4-piperidinones and to reactions with a variety of structurally diverse aldehydes and ketones.
Silyl-Heck Reactions for the Preparation of Unsaturated Organosilanes.

Few methods exist to directly install silyl functionality onto olefins. This Synpacts article highlights the state of the art of the silyl-Heck reaction and our recently developed conditions for preparing allyl and vinyl silanes from terminal alkenes using this method.
CONCISE AND EFFICIENT TOTAL SYNTHESES OF ALKANNIN AND SHIKONIN

Two enantiomic natural products with wound-healing properties, alkannin (1) and shikonin (2), are accessible by a short and efficient total synthesis. The success was achieved by a novel protecting system for masking of 5,8-dihydroxy-1,4-naphthoquinones (naphthazarins) and a highly stereoselective ketone reduction.
Convenient Synthesis of N,N′‐bis‐protected‐3,3′‐diiodo‐2,2′‐biindoles

Abstract A convenient synthesis of N,N′‐bis‐protected 3,3′‐diiodo‐2,2′‐biindoles 4–7 from 2,2′‐biindole (1) is described.