cssi/SciSciGPT-SciSciNet huggingface dataset:
Uncovering Group Level Insights with Accordant Clustering.

Clustering is a widely-used data mining tool, which aims to discover partitions of similar items in data. We introduce a new clustering paradigm, \emph{accordant clustering}, which enables the discovery of (predefined) group level insights. Unlike previous clustering paradigms that aim to understand relationships amongst the individual members, the goal of accordant clustering is to uncover insights at the group level through the analysis of their members. Group level insight can often support a call to action that cannot be informed through previous clustering techniques. We propose the first accordant clustering algorithm, and prove that it finds near-optimal solutions when data possesses inherent cluster structure. The insights revealed by accordant clusterings enabled experts in the field of medicine to isolate successful treatments for a neurodegenerative disease, and those in finance to discover patterns of unnecessary spending.
Is An Atrial Defibrillator Still An Option In Treating Patients With Atrial Fibrillation

Atrial fibrillation (AF) is a common disorder associated with significant morbidities and presents several challenges for the control of symptoms and prevention of long-term implications. Atrial defibrillators (ADs), used for rhythm control in patients with symptoms refractory to medical therapy, can detect recurrences of the arrhythmia, allow prompt patient-directed treatment, and have the potential to reduce hospitalizations and improve quality of life. The efficacy of this form of therapy is highest in patients with paroxysmal AF, and with the use of a coronary sinus shocking lead. While R-wave synchronized shocks are a prerequisite for a safe use, the procedure is well tolerated and usually not associated with long-term psychological side effects. Limitations of ADs include acute and chronic complications related to cardiac rhythm device implantation, the requirement in some cases for more than one shock to terminate AF, the discomfort from shocks, as well as the need for sedation to alleviate pain from the shocks. With the ever-expanding role of catheter-based therapies for AF, it seems that the role of ADs in this regard is rather limited.
B-cell activating factor (BAFF) plasma level at the time of chronic GvHD diagnosis is a potential predictor of non-relapse mortality

Biological markers for risk stratification of chronic GvHD (cGvHD) could improve the care of patients undergoing allogeneic hematopoietic stem cell transplantation. Increased plasma levels of B-cell activating factor (BAFF), chemokine (C-X-C motif) ligand 9 (CXCL9) and elafin have been associated with the diagnosis, but not with outcome in patients with cGvHD. We evaluated the association between levels of these soluble proteins, measured by ELISA at the time of cGvHD diagnosis and before the initiation of therapy, with non-relapse-mortality (NRM). Based on the log-transformed values, factor levels were divided into tertiles defined respectively as low, intermediate, and high levels. On univariable analysis, BAFF levels were significantly associated with NRM, whereas CXCL9 and elafin levels were not. Both low (⩽2.3 ng/mL, hazard ratio (HR)=5.8, P=0.03) and high (>5.7 ng/mL, HR=5.4, P=0.03) BAFF levels were associated with a significantly higher NRM compared with intermediate BAFF level. The significant effect of high or low BAFF levels persisted in multivariable analysis. A subset of cGvHD patients had persistently low BAFF levels. In conclusion, our data show that BAFF levels at the time of cGvHD diagnosis are associated with NRM, and also are potentially useful for risk stratification. These results warrant confirmation in larger studies.
The role of bankers in the U.S. syndicated loan market

Abstract I construct a novel dataset of individual bankers in the U.S. syndicated loan market to analyze the impact of bankers for the largest, most transparent borrowers. Bankers exhibit time-invariant preferences for specific loan characteristics, or styles. In addition, exploiting within-borrower variation in personal relationship strength from banker turnover, I find that stronger relationships lead to significantly lower interest rates. This effect is stronger if borrowers lack a credit rating or issue less frequent and shorter horizon management reports. Relationship loans are associated with fewer bankruptcies and fewer favorable modifications in renegotiations.
Spatial Structure of the Mormon Cricket Gut Microbiome and its Predicted Contribution to Nutrition and Immune Function

The gut microbiome of insects plays an important role in their ecology and evolution, participating in nutrient acquisition, immunity, and behavior. Microbial community structure within the gut is heavily influenced by differences among gut regions in morphology and physiology, which determine the niches available for microbes to colonize. We present a high-resolution analysis of the structure of the gut microbiome in the Mormon cricket Anabrus simplex, an insect known for its periodic outbreaks in the western United States and nutrition-dependent mating system. The Mormon cricket microbiome was dominated by eleven taxa from the Lactobacillaceae, Enterobacteriaceae, and Streptococcaeae. While most of these were represented in all gut regions, there were marked differences in their relative abundance, with lactic-acid bacteria (Lactobacillaceae) more common in the foregut and midgut and enteric (Enterobacteriaceae) bacteria more common in the hindgut. Differences in community structure were driven by variation in the relative prevalence of three groups: a Lactobacillus in the foregut, Pediococcus lactic-acid bacteria in the midgut, and Pantoea agglomerans, an enteric bacterium, in the hindgut. These taxa have been shown to have beneficial effects on their hosts in insects and other animals by improving nutrition, increasing resistance to pathogens, and modulating social behavior. Using PICRUSt to predict gene content from our 16S rRNA sequences, we found enzymes that participate in carbohydrate metabolism and pathogen defense in other orthopterans. These were predominately represented in the hindgut and midgut, the most important sites for nutrition and pathogen defense. Phylogenetic analysis of 16S rRNA sequences from cultured isolates indicated low levels of divergence from sequences derived from plants and other insects, suggesting that these bacteria are likely to be exchanged between Mormon crickets and the environment. Our study shows strong spatial variation in microbiome community structure, which influences predicted gene content and thus the potential of the microbiome to influence host function
Heterogeneous Treatment Effects in the Presence of Self-Selection: A Propensity Score Perspective:

An essential feature common to all empirical social research is variability across units of analysis. Individuals differ not only in background characteristics but also in how they respond to a par...
A New Subgenus and Species of Petricola (Mollusca: Bivalvia) from the Pliocene of Southern Florida

Mrs. R. C. Hoerle of West Palm Beach Florida, recently sent an unusual bivalved mollusk requesting information as to its possible systematic position. It was collected from a coral-rich faunal association that had been dredged from a drainage canal southwest of Immokalee in northern Collier County, Florida. The associated fauna in the spoil bank is thought to be predominantly of Caloosahatchee (upper Pliocene) age although a few forms suggest an upper Pinecrest (middle Pliocene) assignment. The hinge and pallial line of the species clearly reveal its relationship with the genus Petricola Lamarck, 1801, but the ornamentation is wholly different from that to be observed in that genus and, in a general way, is so mew hat reminiscent of that observed in some unionid forms. Accordingly, the species is here described as representative of a new subgenus of Petricola.
Do Peer Warnings Affect CEO Compensation

SYNOPSIS: In this study, focusing on the period 1996–2010, we conduct an empirical investigation of how warnings by industry peer firms about future earnings affect CEO compensation structure. These warnings contain information about the industry, signaling dim industry prospects and possibly triggering negative spillovers on stock prices. We predict that firms respond to industry-wide negative information by changing the compensation mix to make it more future oriented and by reducing pay-performance sensitivity to shield CEOs from negative factors beyond their control. We find that (1) for firms that issue warnings, peer warnings are associated with a reduction in pay-performance sensitivity; and (2) for firms that do not issue warnings, peer warnings are associated with a modification in compensation mix, such that it becomes more equity based and future oriented, similar to the adjustment made to CEO compensation in the wake of self-warnings. Our results are robust to different definitions of warnings...
Dynamic nuclear polarization at 9 T using a novel 250 GHz gyrotron microwave source

Abstract In this communication, we report enhancements of nuclear spin polarization by dynamic nuclear polarization (DNP) in static and spinning solids at a magnetic field strength of 9 T (250 GHz for g=2 electrons, 380 MHz for 1H). In these experiments, 1H enhancements of up to 170±50 have been observed in 1-13C-glycine dispersed in a 60:40 glycerol/water matrix at temperatures of 20 K; in addition, we have observed significant enhancements in 15N spectra of unoriented pf1-bacteriophage. Finally, enhancements of ∼17 have been obtained in two-dimensional 13C–13C chemical shift correlation spectra of the amino acid U-13C, 15N-proline during magic angle spinning (MAS), demonstrating the stability of the DNP experiment for sustained acquisition and for quantitative experiments incorporating dipolar recoupling. In all cases, we have exploited the thermal mixing DNP mechanism with the nitroxide radical 4-amino-TEMPO as the paramagnetic dopant. These are the highest frequency DNP experiments performed to date and indicate that significant signal enhancements can be realized using the thermal mixing mechanism even at elevated magnetic fields. In large measure, this is due to the high microwave power output of the 250 GHz gyrotron oscillator used in these experiments.
The Effect of Incentive Framing and Descriptive Norms on Internal Whistleblowing

Firms are under increasing pressure to implement effective internal whistleblowing systems. While firms can provide incentives to encourage internal whistleblowing, it remains controversial how such incentives should be structured. We examine whether the effectiveness of incentives encouraging internal whistleblowing is a joint function of the framing of such incentives (reward or penalty) and the strength of descriptive norms supporting internal whistleblowing. We predict and find in a lab experiment that penalties lead to a greater increase in internal whistleblowing (compared to rewards) when descriptive norms supporting whistleblowing are stronger. Our study contributes to the previous accounting literature on dishonesty and the role of management control systems design in promoting honesty and ethical norms in organizations. We also contribute to an emerging accounting literature on the links between controls, norms, and individual behavior by distinguishing between descriptive norms and injunctive norms and by highlighting the interplay between these two types of norms. Our results have important implications for organizations considering adopting incentives to encourage internal whistleblowing. This article is protected by copyright. All rights reserved.
The Cache-Oblivious Gaussian Elimination Paradigm: Theoretical Framework, Parallelization and Experimental Evaluation

We consider triply-nested loops of the type that occur in the standard Gaussian elimination algorithm, which we denote by GEP (or the Gaussian Elimination Paradigm). We present two related cache-oblivious methods I-GEP and C-GEP, both of which reduce the number of cache misses incurred (or I/Os performed) by the computation over that performed by standard GEP by a factor of $\sqrt{M}$, where M is the size of the cache. Cache-oblivious I-GEP computes in-place and solves most of the known applications of GEP including Gaussian elimination and LU-decomposition without pivoting and Floyd-Warshall all-pairs shortest paths. Cache-oblivious C-GEP uses a modest amount of additional space, but is completely general and applies to any code in GEP form. Both I-GEP and C-GEP produce system-independent cache-efficient code, and are potentially applicable to being used by optimizing compilers for loop transformation. We present parallel I-GEP and C-GEP that achieve good speed-up and match the sequential caching performance cache-obliviously for both shared and distributed caches for sufficiently large inputs. We present extensive experimental results for both in-core and out-of-core performance of our algorithms. We consider both sequential and parallel implementations, and compare them with finely-tuned cache-aware BLAS code for matrix multiplication and Gaussian elimination without pivoting. Our results indicate that cache-oblivious GEP offers an attractive trade-off between efficiency and portability.
Fever, Bacteremia, and Death as Complications of Bacteriuria in Women With Long-Term Urethral Catheters

Numbers of nursing home beds now exceed hospital beds in the United States and are usually occupied by women. Urinary incontinence is very common and may be managed with long-term urethral catheters. Bacteriuria invariably results, yet its clinical consequences are not well known. We studied 47 catheterized and bacteriuric women for almost 25 patient-years. The incidence of febrile episodes of possible urinary origin was 1.1 episodes/100 patient-days. Because these were diagnoses of exclusion, even this low incidence may be an overestimate. Most of these episodes were of less than or equal to 38.3 C (101.0 F), lasted for less than one day, and resolved without antibiotic therapy. Six deaths, half the total from all causes, occurred during these episodes, an incidence 60 times that during afebrile periods. Deaths and bacteremias were significantly associated with episodes of greater than or equal to 38.8 C (102.0 F). In the individual patient, these risks should be weighed against benefits of patient comfort, family satisfaction, and prevention and management of decubitus ulcers.
Delayed Rupture of Renal Pseudoaneurysm: Complication of Percutaneous Nephrostomy

Percutaneous nephrostomy has become an increasingly acceptable therapeutic alternative, both for high-risk patients and for patients in whom the technique offers delay on avoidance of major surgery. Lack of major morbidity or mortality, palliation of symptoms, and reduced convalescent period are major advantages [i -3]. However, the procedure is not without its risks. We report a case of traumatic renal artery pseudoaneurysm following percutaneous nephrostomy with delayed rupture into the collecting system. This case also exhibits many of the therapeutic options now available to the interventional radiologist.
Tumor Vascular Signals in Renal Masses: Detection With Doppler US

The vascularity of 49 renal masses (26 malignant and 23 benign lesions) was investigated with duplex Doppler ultrasound. Doppler signals obtained at the margins of renal masses were defined as "tumor signals" when the Doppler-shifted frequency of the lesion exceeded the frequency shift in the ipsilateral main renal artery. These exceeded 2.5 kHz with a 3-MHz insonating frequency. Among the 26 renal masses that subsequently proved to be malignant, tumor signals were obtained in 15 of 18 (83%) untreated renal cell carcinomas, in three of four Wilms tumors, and in two patients with metastases to the kidney, but not in the one patient with lymphoma. None of the 23 benign renal masses demonstrated tumor signals. Tumor vascularity in malignant lesions gives rise to abnormal, high-velocity, Doppler-shifted signals that can help in the differential diagnosis of renal masses.
Basal Cell Hyperplasia of the Prostate

Basal cell hyperplasia of the prostate is a rare, benign lesion that often has been misdiagnosed as adenocarcinoma. Thirteen cases of basal cell hyperplasia were reviewed. All of the patients were over 60 years of age (range 63–83) and all had benign prostatic hypertrophy in addition to basal cell hyperplasia. Histologic features consisted of nests of uniform small cells with scant cytoplasm forming solid nests and acinar structures. Some foci had nodular configurations and most were located within larger nodules of “typical” glandular hyperplasia. In some instances there was a merging of the two types of hyperplasia. There was neither nuclear atypia nor pleomorphism, and the adjacent stroma was hyperplastic. Small elongated cells with desmosomes and nonspecific, dense bodies were seen on electron microscopic studies of formalin-fixed material. The architectural and cytologic features of the basal cell proliferations were not those of carcinoma. However, synchronously, two patients demonstrated foci of prostate carcinoma unrelated to the basal cell hyperplasia.
Spectrum of Gas Within the Kidney. Emphysematous Pyelonephritis and Emphysematous Pyelitis

Renal emphysema is an important clinical entity that is not addressed frequently in the medical literature. The affected patients may have gas within the renal parenchyma, emphysematous pyelonephritis, or confined to the collecting system, emphysematous pyelitis. Two patients that illustrate the spectrum of this entity are described. The literature has been reviewed to determine the clinical features of each disorder and to provide a schema for diagnosis and management. Emphysematous pyelonephritis is seen primarily in diabetic patients, whereas emphysematous pyelitis is recognized most often in association with urinary tract obstruction. The diagnosis is made radiographically by demonstrating renal gas on plain abdominal roentgenography or intravenous pyelography. Location and extent of renal gas are best evaluated by computed tomographic scanning. Intraparenchymal gas usually requires nephrectomy, whereas successful therapy of gas limited to the collecting system involves medical management, with a drainage procedure when obstruction coexists.
Noncompaction cardiomyopathy and heterotaxy syndrome

Left ventricular noncompaction cardiomyopathy (LVNC) is characterized by compact and trabecular layers of the left ventricular myocardium. This cardiomyopathy may occur with congenital heart disease (CHD). Single cases document co-occurrence of LVNC and heterotaxy, but no data exist regarding the prevalence of this association. This study sought to determine whether a non-random association of LVNC and heterotaxy exists by evaluating the prevalence of LVNC in patients with heterotaxy. In a retrospective review of the Indiana Network for Patient Care, we identified 172 patients with heterotaxy (69 male, 103 female). Echocardiography and cardiac magnetic resonance imaging results were independently reviewed by two cardiologists to ensure reproducibility of LVNC. A total of 13/172 (7.5%) patients met imaging criteria for LVNC. The CHD identified in this subgroup included atrioventricular septal defects [11], dextrocardia [10], systemic and pulmonary venous return abnormalities [7], and transposition of the great arteries [5]. From this subgroup, 61% (n = 8) of the patients developed arrhythmias; and 61% (n = 8) required medical management for chronic heart failure. This study indicates that LVNC has increased prevalence among patients with heterotaxy when compared to the general population (0.014-1.3%) suggesting possible common genetic mechanisms. Interestingly, mice with a loss of function of Scrib or Vangl2 genes showed abnormal compaction of the ventricles, anomalies in cardiac looping, and septation defects in previous studies. Recognition of the association between LVNC and heterotaxy is important for various reasons. First, the increased risk of arrhythmias demonstrated in our population. Secondly, theoretical risk of thromboembolic events remains in any LVNC population. Finally, many patients with heterotaxy undergo cardiac surgery (corrective and palliative) and when this is associated with LVNC, patients should be presumed to incur a higher peri-operative morbidity based on previous studies. Further research will continue to determine long-term and to corroborate genetic pathways.
Constrained Trajectory Optimization for Planetary Entry via Sequential Convex Programming

In this paper, the highly nonlinear planetary-entry optimal control problem is formulated as a sequence of convex problems to facilitate rapid solution. The nonconvex control constraint is avoided ...
The M&A exit outcomes of new, young firms

We examine the M&A exit behavior of new, young businesses and the way the exit is shaped by their innovative capabilities and their growth in employment. Using a large sample of startups founded in 2004, we find that businesses organized as corporations had very different acquisition outcomes than those organized as sole proprietorships. These different acquisition outcomes could be explained by differences in innovation and growth potential in the startup year as well throughout the business’ lifetime. Our results suggest that higher innovation and employment growth explain the likelihood of M&A exit for new, young corporations but not for sole proprietorships. These results indicate that acquirers value the growth potential signaled by corporations through intellectual property rights and growth in employment and, therefore, businesses with high quality innovations are the most attractive targets for acquisitions. Young corporations with external equity investors are more likely to become M&A targets, as angels or venture capitalists have the first opportunity to liquidate some or all their equity holdings when the business becomes an acquisition target. Our results also show that young corporations owned by serial entrepreneurs are more likely to become M&A targets. From an acquirer’s perspective, entrepreneurs with startup experience are typically favored due to their proven ability to realize the growth potential of a venture as well as their willingness and ability to harvest value for themselves and their investors.
Wrangling Categorical Data in R

ABSTRACTData wrangling is a critical foundation of data science, and wrangling of categorical data is an important component of this process. However, categorical data can introduce unique issues in data wrangling, particularly in real-world settings with collaborators and periodically-updated dynamic data. This article discusses common problems arising from categorical variable transformations in R, demonstrates the use of factors, and suggests approaches to address data wrangling challenges. For each problem, we present at least two strategies for management, one in base R and the other from the “tidyverse.” We consider several motivating examples, suggest defensive coding strategies, and outline principles for data wrangling to help ensure data quality and sound analysis. Supplementary materials for this article are available online.
The continental tectosphere and Earth's long-wavelength gravity field

To estimate the average density contrast associated with the continental tectosphere, we separately project the degree 2-36 non-hydrostatic geoid and free-air gravity anomalies onto several tectonic regionalizations. Because both the regionalizations and the geoid have distinctly red spectra, we do not use conventional statistical analysis, which is based on the assumption of white spectra. Rather, we utilize a Monte Carlo approach that incorporates the spectral properties of these fields. These simulations reveal that the undulations of Earth's geoid correlate with surface tectonics no better than they would were it randomly oriented with respect to the surface. However, our simulations indicate that free-air gravity anomalies correlate with surface tectonics better than almost 98% of our trials in which the free-air gravity anomalies were randomly oriented with respect to Earth's surface. The average geoid anomaly and free-air gravity anomaly over platforms and shields are significant at slightly better than the one-standard-deviation level: y11" 8 m and y4" 3 mgal, . respectively. After removing from the geoid estimated contributions associated with 1 a simple model of the continental . . . crust and oceanic lithosphere, 2 the lower mantle, 3 subducted slabs, and 4 remnant glacial isostatic disequilibrium, we estimate a platform and shield signal of y8" 4 m. We conclude that there is little contribution of platforms and shields to the gravity field, consistent with their keels having small density contrasts. Using this estimate of the platform and shield signal, and previous estimates of upper-mantle shear-wave travel-time perturbations, we find that the average value of . Eln rrElnn within the 140-440 km depth range is 0.04" 0.02. A continental tectosphere with an isopycnic equal-density s . structure Eln rrElnn s 0 enforced by compositional variations is consistent with this result at the 2.0 s level. Without s
Adding Support for Theory in Open Science Big Data

Open Science Big Data is emerging as an important area of research and software development. Although there are several high quality frameworks for Big Data, additional capabilities are needed for Open Science Big Data. These include data provenance, citable reusable data, data sources providing links to research literature, relationships to other data and theories, transparent analysis/reproducibility, data privacy, new optimizations/advanced algorithms, data curation, data storage and transfer. An important part of science is explanation of results, ideally leading to theory formation. In this paper, we examine means for supporting the use of theory in big data analytics as well as using big data to assist in theory formation. One approach is to fit data in a way that is compatible with some theory, existing or new. Functional Data Analysis allows precise fitting of data as well as penalties for lack of smoothness or even departure from theoretical expectations. This paper discusses principal differential analysis and related techniques for fitting data where, for example, a time-based process is governed by an ordinary differential equation. Automation in theory formation is also considered. Case studies in the fields of computational economics and finance are considered.
Catalytic Methane Monofunctionalization by an Electrogenerated High-Valent Pd Intermediate

Electrophilic high-valent metal ions are potent intermediates for the catalytic functionalization of methane, but in many cases, their high redox potentials make these intermediates difficult or impossible to access using mild stoichiometric oxidants derived from O2. Herein, we establish electrochemical oxidation as a versatile new strategy for accessing high-valent methane monofunctionalization catalysts. We provide evidence for the electrochemical oxidation of simple PdSO4 in concentrated sulfuric acid electrolytes to generate a putative Pd2III,III species in an all-oxidic ligand field. This electrogenerated high-valent Pd complex rapidly activates methane with a low barrier of 25.9 (±2.6) kcal/mol, generating methanol precursors methyl bisulfate (CH3OSO3H) and methanesulfonic acid (CH3SO3H) via concurrent faradaic and nonfaradaic reaction pathways. This work enables new electrochemical approaches for promoting rapid methane monofunctionalization.
Comparison of Neurologic Trauma and Motorcycle Helmet Use in Drivers vs Passengers.

This study compares postcrash prevalences of neurological and head and neck injuries in motorcycle drivers and passengers, stratified by helmet use.
Whole-Cell Scale Dynamic Organization of Lysosomes Revealed by Spatial Statistical Analysis

In eukaryotic cells, lysosomes are distributed in the cytoplasm as individual membrane-bound compartments to degrade macromolecules and to control cellular metabolism. A fundamental yet unanswered question is whether and, if so, how individual lysosomes are organized spatially to coordinate and integrate their functions. To address this question, we analyzed their collective behavior in cultured cells using spatial statistical techniques. We found that in single cells, lysosomes maintain non-random, stable, yet distinct spatial distributions mediated by the cytoskeleton, the endoplasmic reticulum (ER), and lysosomal biogenesis. Throughout the intracellular space, lysosomes form dynamic clusters that significantly increase their interactions with endosomes. Cluster formation is associated with local increases in ER spatial density but does not depend on fusion with endosomes or spatial exclusion by mitochondria. Taken together, our findings reveal whole-cell scale spatial organization of lysosomes and provide insights into how organelle interactions are mediated and regulated across the entire intracellular space.
Consumer-Lending Discrimination in the FinTech Era

Abstract U.S. fair-lending law prohibits lenders from making credit determinations that disparately affect minority borrowers if those determinations are based on characteristics unrelated to creditworthiness. Using an identification under this rule, we show risk-equivalent Latinx/Black borrowers pay significantly higher interest rates on GSE-securitized and FHA-insured loans, particularly in high-minority-share neighborhoods. We estimate these rate differences cost minority borrowers over $450 million yearly. FinTech lenders’ rate disparities were similar to those of non-Fintech lenders for GSE mortgages, but lower for FHA mortgages issued in 2009–2015 and for FHA refi mortgages issued in 2018–2019.
Analysis of Linear Time Invariant Systems With Time Delay

Time Delay Control has recently been suggested as an alternative scheme for control of systems with unknown dynamics and unpredictable disturbances. The proposed control algorithm does not require an explicit plant model nor does it depend on the estimation of specific plant parameters. Rather, it uses information in the recent past to directly estimate the unknown dynamics at any given instant, through time delay. In earlier papers, analysis and implementation of Time Delay Controller for nonlinear systems were discussed. This paper analyzes the continuous Time Delay Controller for a class of linear systems and presents necessary and sufficient conditions for control system stability
The Mass-Metallicity Relation of a z ~ 2 Protocluster with MOSFIRE

We present Keck/MOSFIRE observations of the role of environment in the formation of galaxies at z ∼ 2. Using K-band spectroscopy of Hand (N II) emission lines, we have analyzed the metallicities of galaxies within and around a z = 2.3 protocluster discovered in the HS1700+643 field. Our main sample consists of 23 protocluster and 20 field galaxies with estimates of stellar masses and gas-phase metallicities based on the N2 strong-line metallicity indicator. With these data we have examined the mass-metallicity relation (MZR) with respect to environment at z ∼ 2. We find that field galaxies follow the well-established trend between stellar mass and metallicity, such that more massive galaxies have larger metallicities. The protocluster galaxies, however, do not exhibit a dependence of metallicity on mass, with the low-mass protocluster galaxies showing an enhancement in metallicity compared to field galaxies spanning the same mass range. A comparison with galaxy formation models suggests that the mass-dependent environmental trend we observed can be qualitatively explained in the context of the recycling of "momentum-driven" galaxy wind material. Accordingly, winds are recycled on a shorter timescale in denser environments, leading to an enhancement in metallicity at fixed mass for all but the most massive galaxies. Future hydrodynamical simulations of z ∼ 2 overdensities matching the one in the HS1700 field will be crucial for understanding the origin of the observed environmental trend in detail. Subject headings: galaxies: high-redshift, galaxies: clusters: general, galaxies: formation, galaxies: abundances, galaxies: evolution
Recurrence quantification analysis as a method for studying text comprehension dynamics

Self-explanations are commonly used to assess on-line reading comprehension processes. However, traditional methods of analysis ignore important temporal variations in these explanations. This study investigated how dynamical systems theory could be used to reveal linguistic patterns that are predictive of self-explanation quality. High school students (n = 232) generated self-explanations while they read a science text. Recurrence Plots were generated to show qualitative differences in students' linguistic sequences that were later quantified by indices derived by Recurrence Quantification Analysis (RQA). To predict self-explanation quality, RQA indices, along with summative measures (i.e., number of words, mean word length, and type-token ration) and general reading ability, served as predictors in a series of regression models. Regression analyses indicated that recurrence in students' self-explanations significantly predicted human rated self-explanation quality, even after controlling for summative measures of self-explanations, individual differences, and the text that was read (R2 = 0.68). These results demonstrate the utility of RQA in exposing and quantifying temporal structure in student's self-explanations. Further, they imply that dynamical systems methodology can be used to uncover important processes that occur during comprehension.
A matrix expander Chernoff bound

We prove a Chernoff-type bound for sums of matrix-valued random variables sampled via a random walk on an expander, confirming a conjecture due to [Wigderson and Xiao 06]. Our proof is based on a new multi-matrix extension of the Golden-Thompson inequality which improves upon the inequality in [Sutter, Berta and Tomamichel 17], as well as an adaptation of an argument for the scalar case due to [Healy 08]. Our new multi-matrix Golden-Thompson inequality could be of independent interest. Secondarily, we also provide a generic reduction showing that any concentration inequality for vector-valued martingales implies a concentration inequality for the corresponding expander walk, with a weakening of parameters proportional to the squared mixing time.
Strong formulations for quadratic optimization with M-matrices and indicator variables

We study quadratic optimization with indicator variables and an M-matrix, i.e., a PSD matrix with non-positive off-diagonal entries, which arises directly in image segmentation and portfolio optimization with transaction costs, as well as a substructure of general quadratic optimization problems. We prove, under mild assumptions, that the minimization problem is solvable in polynomial time by showing its equivalence to a submodular minimization problem. To strengthen the formulation, we decompose the quadratic function into a sum of simple quadratic functions with at most two indicator variables each, and provide the convex-hull descriptions of these sets. We also describe strong conic quadratic valid inequalities. Preliminary computational experiments indicate that the proposed inequalities can substantially improve the strength of the continuous relaxations with respect to the standard perspective reformulation.
The eardrums move when the eyes move: A multisensory effect on the mechanics of hearing

Interactions between sensory pathways such as the visual and auditory systems are known to occur in the brain, but where they first occur is uncertain. Here, we show a novel multimodal interaction evident at the eardrum. Ear canal microphone measurements in humans (n = 19 ears in 16 subjects) and monkeys (n = 5 ears in 3 subjects) performing a saccadic eye movement task to visual targets indicated that the eardrum moves in conjunction with the eye movement. The eardrum motion was oscillatory and began as early as 10 ms before saccade onset in humans or with saccade onset in monkeys. These eardrum movements, which we dub Eye Movement Related Eardrum Oscillations (EMREOs), occurred in the absence of a sound stimulus. The EMREOs’ amplitude and phase depended on the direction and horizontal amplitude of the saccade. They lasted throughout the saccade and well into subsequent periods of steady fixation. We discuss the possibility that the mechanisms underlying EMREOs create eye movement-related binaural cues that may aid the brain in evaluating the relationship between visual and auditory stimulus locations as the eyes move.Interactions between sensory pathways such as the visual and auditory systems are known to occur in the brain, but where they first occur is uncertain. Here, we show a novel multimodal interaction evident at the eardrum. Ear canal microphone measurements in humans (n = 19 ears in 16 subjects) and monkeys (n = 5 ears in 3 subjects) performing a saccadic eye movement task to visual targets indicated that the eardrum moves in conjunction with the eye movement. The eardrum motion was oscillatory and began as early as 10 ms before saccade onset in humans or with saccade onset in monkeys. These eardrum movements, which we dub Eye Movement Related Eardrum Oscillations (EMREOs), occurred in the absence of a sound stimulus. The EMREOs’ amplitude and phase depended on the direction and horizontal amplitude of the saccade. They lasted throughout the saccade and well into subsequent periods of steady fixation. We discuss the possibility that the mechanisms underlying EMREOs create eye movement-related binaural cues t...
A ``Special Effort'' to Provide Improved Sounding and Cloud-Motion Wind Data for FGGE

Enhancement and editing of high-density cloud motion wind assessments and research satellite soundings have been necessary to improve the quality of data used in The Global Weather Experiment. Editing operations are conducted by a man-computer interactive data access system. Editing will focus on such inputs as non-US satellite data, NOAA operational sounding and wind data sets, wind data from the Indian Ocean satellite, dropwindsonde data, and tropical mesoscale wind data. Improved techniques for deriving cloud heights and higher resolution sounding in meteorologically active areas are principal parts of the data enhancement program.
LA SOBERANÍA, EL PODER CONSTITUYENTE Y UNA NUEVA CONSTITUCIÓN PARA CHILE

Este trabajo pretende abordar el concepto de soberania y sus diversas clasificaciones, desde una perspectiva tanto diacronica como sincronica. Del mismo modo, se examina el concepto de poder constituyente. Finalmente se aplican estos conceptos a los intentos recientes en Chile de discutir una nueva Constitucion. El articulo afirma que la mejor manera de ser fiel al concepto de soberania es recurriendo al mecanismo de la asamblea constituyente
RNA-binding proteins with basic-acidic dipeptide (BAD) domains self-assemble and aggregate in Alzheimer's disease

The U1 small nuclear ribonucleoprotein 70 kDa (U1-70K) and other RNA-binding proteins (RBPs) are mislocalized to cytoplasmic neurofibrillary Tau aggregates in Alzheimer's disease (AD), yet the co-aggregation mechanisms are incompletely understood. U1-70K harbors two disordered low–complexity domains (LC1 and LC2) that are necessary for aggregation in AD brain extracts. The LC1 domain contains highly repetitive basic (Arg/Lys) and acidic (Asp/Glu) residues, referred to as a basic-acidic dipeptide (BAD) domain. We report here that this domain shares many of the properties of the Gln/Asn-rich LC domains in RBPs that also aggregate in neurodegenerative disease. These properties included self-assembly into oligomers and localization to nuclear granules. Co-immunoprecipitations of recombinant U1-70K and deletions lacking the LC domain(s) followed by quantitative proteomic analyses were used to resolve functional classes of U1-70K-interacting proteins that depend on the BAD domain for their interaction. Within this interaction network, we identified a class of RBPs with BAD domains nearly identical to that found in U1-70K. Two members of this class, LUC7L3 and RBM25, required their respective BAD domains for reciprocal interactions with U1-70K and nuclear granule localization. Strikingly, a significant proportion of RBPs with BAD domains had elevated insolubility in the AD brain proteome. Furthermore, we show that the BAD domain of U1-70K can interact with Tau from AD brains but not from other tauopathies. These findings highlight a mechanistic role for BAD domains in stabilizing RBP interactions and in potentially mediating co-aggregation with the pathological AD–specific Tau isoforms.
Total synthesis and biological evaluation of +-kalkitoxin, a cytotoxic metabolite of the cyanobacterium Lyngbya majuscula.

(+)-Kalkitoxin, a metabolite of the marine cyanobacterium Lyngbya majuscula, was synthesized from (R)-2-methylbutyric acid, (R)-cysteine, and (3S, 4S, 6S)-3,4,6-trimethyl-8-(methylamino)octanoic acid. A key step in the synthesis was installation of the anti,anti methyl stereotriad by means of a tandem asymmetric conjugate addition of an organocopper species to an α,β-unsaturated N-acyl oxazolidin-2-one followed in situ by α-methylation of the resultant enolate. The thiazoline portion of kalkitoxin was assembled by titanium tetrachloride catalyzed cyclization of a vinyl substituted amido thiol.
Circuit lower bounds for nondeterministic quasi-polytime: an easy witness lemma for NP and NQP

We prove that if every problem in NP has nk-size circuits for a fixed constant k, then for every NP-verifier and every yes-instance x of length n for that verifier, the verifier’s search space has an nO(k3)-size witness circuit: a witness for x that can be encoded with a circuit of only nO(k3) size. An analogous statement is proved for nondeterministic quasi-polynomial time, i.e., NQP = NTIME[nlogO(1) n]. This significantly extends the Easy Witness Lemma of Impagliazzo, Kabanets, and Wigderson [JCSS’02] which only held for larger nondeterministic classes such as NEXP. As a consequence, the connections between circuit-analysis algorithms and circuit lower bounds can be considerably sharpened: algorithms for approximately counting satisfying assignments to given circuits which improve over exhaustive search can imply circuit lower bounds for functions in NQP or even NP. To illustrate, applying known algorithms for satisfiability of ACC ∘ THR circuits [R. Williams, STOC 2014] we conclude that for every fixed k, NQP does not have nlogk n-size ACC ∘ THR circuits.
Numerical Bifurcation and Spectral Stability of Wavetrains in Bidirectional Whitham Models

We consider several different bidirectional Whitham equations that have recently appeared in the literature. Each of these models combine the full two-way dispersion relation from the incompressible Euler equations with a canonical shallow water nonlinearity, providing nonlocal model equations that may be expected to exhibit some of the interesting high-frequency phenomena present in the Euler equations that standard "long-wave" theories fail to capture. Of particular interest here is the existence and stability of periodic traveling wave solutions in such models. Using numerical bifurcation techniques we construct global bifurcation diagrams for each system and compare the global structure of branches, together with the possibility of bifurcation branches terminating in a "highest" singular (peaked/cusped) wave. We also numerically approximate the stability spectrum along these bifurcation branches and compare the stability predictions of these models. Our results confirm a number of analytical results concerning the stability of asymptotically small waves in these models and provide new insights into the existence and stability of large amplitude waves.
COMPUTATIONAL ELECTRONICS AND 21ST CENTURY EDUCATION

The continued scaling of semiconductor devices and the difficulties associated with time and cost of manufacturing these novel device design has been the primary driving force for the significantly increased interest in Computational Electronics which now, in addition to theory and experiments, is being considered as a third important mode in the design and development of novel nanoscale devices. In addition to its significant role in industrial research, modeling and simulation also brings into the picture alternative education modes in which students, by running certain subset of tools that, for example, the nanoHUB offers, can get hands-on experience on the operation of nanoscale devices and can also look into the variation of internal variables that can not be measured experimentally, like the spatial variation of the electron density in the channel in the pre- and post-pichoff regime of operation, electric field profiles which can be used to tailor the electron density to avoid junction breakdown, etc. In summary, Computational Electronics is emerging as a very important field for future device design in both industry and academia.
Language processing fluency and verbal working memory in prelingually deaf long-term cochlear implant users: A pilot study.

Objective: Verbal working memory (WM) is more strongly correlated with spoken language skills in prelingually deaf, early-implanted cochlear implant (CI) users than in normal-hearing (NH) peers, su...
Global Convergence of Policy Gradient Methods for the Linear Quadratic Regulator.

Direct policy gradient methods for reinforcement learning and continuous control problems are a popular approach for a variety of reasons: 1) they are easy to implement without explicit knowledge of the underlying model 2) they are an "end-to-end" approach, directly optimizing the performance metric of interest 3) they inherently allow for richly parameterized policies. A notable drawback is that even in the most basic continuous control problem (that of linear quadratic regulators), these methods must solve a non-convex optimization problem, where little is understood about their efficiency from both computational and statistical perspectives. In contrast, system identification and model based planning in optimal control theory have a much more solid theoretical footing, where much is known with regards to their computational and statistical properties. This work bridges this gap showing that (model free) policy gradient methods globally converge to the optimal solution and are efficient (polynomially so in relevant problem dependent quantities) with regards to their sample and computational complexities.
Efficiently Learning Mixtures of Mallows Models

Mixtures of Mallows models are a popular generative model for ranking data coming from a heterogeneous population. They have a variety of applications including social choice, recommendation systems and natural language processing. Here we give the first polynomial time algorithm for provably learning the parameters of a mixture of Mallows models with any constant number of components. Prior to our work, only the two component case had been settled. Our analysis revolves around a determinantal identity of Zagier which was proven in the context of mathematical physics, which we use to show polynomial identifiability and ultimately to construct test functions to peel off one component at a time. To complement our upper bounds, we show information-theoretic lower bounds on the sample complexity as well as lower bounds against restricted families of algorithms that make only local queries. Together, these results demonstrate various impediments to improving the dependence on the number of components. They also motivate the study of learning mixtures of Mallows models from the perspective of beyond worst-case analysis. In this direction, we show that when the scaling parameters of the Mallows models have separation, there are much faster learning algorithms.