cssi/SciSciGPT-SciSciNet huggingface dataset:
Some Relations between Stress, Strain, and Temperature in a Pure-Gum Vulcanizate of Gr-S Synthetic Rubber

Stress‐temperature relations at constant elongation and at constant length have been studied in a pure‐gum vulcanizate of GR‐S. Such studies yield information useful for calculations involved in the theory of its elastic behavior, and furnish practical data regarding its tensile properties at different temperatures. The compounding recipe was: 100 parts by weight of GR‐S, 2 parts of sulfur, 1 part of zinc oxide, and 0.5 part of zinc dibutyl dithiocarbamate. The specimens were first held at constant length and constant temperature for a period of ½ hour to 2 hours, after which time the effects of relaxation of stress during the observation of stress‐temperature relations were negligible. The value of the stress after relaxation at each elongation was used to plot a stress‐strain curve. The stress‐temperature relations observed for temperatures below the relaxation temperature were linear and reproducible on successive runs of increasing and decreasing temperature. When the temperature was raised above the relaxation temperature straight lines were not obtained, since further relaxation occurred at the higher temperatures. The intercepts at 0°K for the lines obtained below the temperature of relaxation are useful in evaluating the internal energy changes. The intercepts of the lines representing the experiments at constant elongation were found to be negative. The absolute values were of the order of 10 percent of the stress after relaxation for the lowest elongations, and increased to almost 30 percent of the stress at the highest elongation.
The Redox-Mannich Reaction

A complement to the classic three-component Mannich reaction, the redox-Mannich reaction, utilizes the same starting materials but incorporates an isomerization step that enables the facile preparation of ring-substituted β-amino ketones. Reactions occur under relatively mild conditions and are facilitated by benzoic acid.
Assessment of Alternative Manual Control Methods for Small Unmanned Aerial Vehicles

This paper is a summary of experiments to access alternative methods to control a small (<25 kg)1 Unmanned Aerial Vehicle (UAV) in manual mode. While it is true that the majority of the UAV airborne activities will be in autonomous mode (i.e. using an autopilot) this may not always be the case during takeoffs and landings, or if there is a failure of the autopilot. The requirement for a manual control mode for all flight stages remains in proposed UAV regulations currently being defined both in Canada and the U.S. The question then becomes “If we have to take manual control of the UAV, what is the best method?” The research summarized in this paper is an attempt this question.
Quantum confined colloidal nanorod heterostructures for solar-to-fuel conversion

Solar energy conversion, particularly solar-driven chemical fuel formation, has been intensely studied in the past decades as a potential approach for renewable energy generation. Efficient solar-to-fuel conversion requires artificial photosynthetic systems with strong light absorption, long-lived charge separation and efficient catalysis. Colloidal quantum confined nanoheterostructures have emerged as promising materials for this application because of the ability to tailor their properties through size, shape and composition. In particular, colloidal one-dimensional (1D) semiconductor nanorods (NRs) offer the opportunity to simultaneously maintain quantum confinement in radial dimensions for tunable light absorptions and bulk like carrier transport in the axial direction for long-distance charge separations. In addition, the versatile chemistry of colloidal NRs enables the formation of semiconductor heterojunctions (such as CdSe/CdS dot-in-rod NRs) to separate photogenerated electron–hole pairs and deposition of metallic domains to accept charges and catalyze redox reactions. In this review, we summarize research progress on colloidal NR heterostructures and their applications for solar energy conversion, emphasizing mechanistic insights into the working principle of these systems gained from spectroscopic studies. Following a brief overview of synthesis of various NRs and heterostructures, we introduce their electronic structures and dynamics of exciton and carrier transport and interfacial transfer. We discuss how these exciton and carrier dynamics are controlled by their structures and provide key mechanistic understanding on their photocatalytic performance, including the photo-reduction of a redox mediator (methyl viologen) and light driven H2 generation. We discuss the solar-driven H2 generation mechanism, key efficiency limiting steps, and potential approaches for rational improvement in semiconductor NR/metal heterostructures (such as Pt tipped CdSe@CdS dot-in-rod NRs). Finally, we conclude by pointing out challenges to be addressed in future research.
NOT ALL CEMENTLESS STEMS ARE CREATED EQUAL

Cementless fixation has become dominant for THR throughout the world, but are all stem geometries equivalent in results? Registries are the best source for studying this question because they are absent of personal bias. Results at 5 years allow separation of implants so this time frame was used. Comparing the same articulations (ceramic or metal-on- polyethylene), cementless stems with proximal enhancement (elliptical shape), or a tapered stem with rectangular cross section, have performed better than stems with a slim (blade) AP geometry. Almost all cementless stems reported to registries today are broached only tapered in design.
Augmenting the Taylor rule: Monetary policy and the bond market

I show that augmenting the Taylor rule with bond yields observed at the start of the quarter significantly improves the in-sample and out-of-sample fit. Moreover, the augmented rule produces lower forecast errors than those of linear and non-linear policy models.
Tetrahydroxydiboron-Mediated Palladium-Catalyzed Transfer Hydrogenation and Deuteriation of Alkenes and Alkynes Using Water as the Stoichiometric H or D Atom Donor

There are few examples of catalytic transfer hydrogenations of simple alkenes and alkynes that use water as a stoichiometric H or D atom donor. We have found that diboron reagents efficiently mediate the transfer of H or D atoms from water directly onto unsaturated C–C bonds using a palladium catalyst. This reaction is conducted on a broad variety of alkenes and alkynes at ambient temperature, and boric acid is the sole byproduct. Mechanistic experiments suggest that this reaction is made possible by a hydrogen atom transfer from water that generates a Pd–hydride intermediate. Importantly, complete deuterium incorporation from stoichiometric D2O has also been achieved.
Electronic measurement of cellular volumes. I. Calibration of the apparatus.

A 100-channel pulse height analyzer with automatic read-out mechanisms, in conjunction with an electronic particle counter, makes possible the defermination of frequency distribution curves of red cell volumes in individual patients in 6 minutes. The apparatus can be standardized so that pulse heights are converted mathematically and visually into µ3 without the necessity of hematocrits. Conversion factors have been developed which enable the operator to report his results in terms of analyzer channel volume, pulse height, cellular volume, or relative magnification. The method should have the same clinical applications as Price-Jones’ curves.
Circulating Factor IX Antigen-Inhibitor Complexes in Hemophilia B- Following Infusion of a Factor IX Concentrate

A persistent low-titer factor IX inhibitor was discovered in a patient with severe hemophilia B . The inhibitor was very likely an immunoglobulin, since it was present in serum, was not dialyzable, retained its potency after heating to 56°C, and was bound by staphylococcal protein A (SPA). When the hemophilia B patient with the inhibitor was given therapeutic infusions of factor IX concentrate, the survival of factor IX antigen (IXAg) was markedly prolonged (t½ approximately 60 hr) compared to the survival of IXAg in infused hemophilia B patients lacking an inhibitor (t½ 5 hr). The prolonged survival of IXAg suggested the possibility of circulating immune complexes composed of IXAg and factor IX inhibitor (IX***Inh). Since immunoglobulins bind to SPA via the Fc portion of the molecule, the Fab region is free to bind to antigen. If immune complexes were formed in vivo after a factor IX concentrate infusion, IXAg would be retained by SPA-sepharose due to the linking of IXAg with the inhibitor molecule. As expected, postinfusion plasma from the inhibitor patient (but not from other hemophilia B patients) showed binding of IXAg to the SPA-sepharose. Further evidence for circulating complexes was provided by crossed Immunoelectrophoresis using an antibody to purified factor IX. Preparations containing factor IX alone showed a single fast-moving peak in the gel, whereas postinfusion plasma from the inhibitor patient as well as mixtures in vitro of IXAg and IX***Inh showed an additional slow-moving peak. These studies document the presence of circulating factor IX antigen-inhibitor complexes in a patient with hemophilia B- and a persistent low-titer factor IX inhibitor. To date, clinical evidence of immune complex disease has not been observed.
Using administrative data to assess the impact and sustainability of Rwanda's land tenure regularization

Rwanda's completion, in 2012/13, of a land tenure regularization program covering the entire country allows the use of administrative data to describe initial performance and combine the data with household surveys to quantify to what extent and why subsequent transfers remain informal, and how to address this. In 2014/15, annual volumes of registered sales ranged between 5.6 percent for residential land in Kigali and 0.1 percent for agricultural land in the rest of the country; and US$2.6 billion worth of mortgages were secured against land and property. Yet, informality of transfers in rural areas remains high. Decentralized service provision and information campaigns help reduce but not eliminate the extent of informality. A strategy to test the efficacy of different approaches to ensure full registration, scale up promising ones, and rigorously monitor the effect of doing so is described.
A hyperactive transcriptional state marks genome reactivation at the mitosis–G1 transition

During mitosis, RNA polymerase II (Pol II) and many transcription factors dissociate from chromatin, and transcription ceases globally. Transcription is known to restart in bulk by telophase, but whether de novo transcription at the mitosis-G1 transition is in any way distinct from later in interphase remains unknown. We tracked Pol II occupancy genome-wide in mammalian cells progressing from mitosis through late G1. Unexpectedly, during the earliest rounds of transcription at the mitosis-G1 transition, ∼50% of active genes and distal enhancers exhibit a spike in transcription, exceeding levels observed later in G1 phase. Enhancer-promoter chromatin contacts are depleted during mitosis and restored rapidly upon G1 entry but do not spike. Of the chromatin-associated features examined, histone H3 Lys27 acetylation levels at individual loci in mitosis best predict the mitosis-G1 transcriptional spike. Single-molecule RNA imaging supports that the mitosis-G1 transcriptional spike can constitute the maximum transcriptional activity per DNA copy throughout the cell division cycle. The transcriptional spike occurs heterogeneously and propagates to cell-to-cell differences in mature mRNA expression. Our results raise the possibility that passage through the mitosis-G1 transition might predispose cells to diverge in gene expression states.
Lobbying and Uniform Disclosure Regulation

This study examines the costs and benefits of uniform accounting regulation in the presence of heterogeneous firms that can lobby the regulator. A commitment to uniform regulation reduces economic distortions caused by lobbying by creating a free-rider problem between lobbying firms at the cost of forcing the same treatment on heterogeneous firms. Resolving this tradeoff, an institutional commitment to uniformity is socially desirable when firms are sufficiently homogeneous or the costs of lobbying to society are large. We show that the regulatory intensity for a given firm can be increasing or decreasing in the degree of uniformity, even though uniformity always reduces lobbying. Our analysis sheds light on the determinants of standard-setting institutions and their effects on corporate governance and lobbying efforts.
The Superposition of Eastward and Westward Rossby Waves in Response to Localized Forcing

AbstractRossby waves are a principal form of atmospheric communication between disparate parts of the climate system. These planetary waves are typically excited by diabatic or orographic forcing and can be subject to considerable downstream modification. Because of differences in wave properties, including vertical structure, phase speed, and group velocity, Rossby waves exhibit a wide range of behaviors. This study demonstrates the combined effects of eastward-propagating stationary barotropic Rossby waves and westward-propagating very-low-zonal-wavenumber stationary barotropic Rossby waves on the atmospheric response to wintertime El Nino convective forcing over the tropical Pacific. Experiments are conducted using the Community Atmosphere Model, version 4.0, in which both diabatic forcing over the Pacific and localized relaxation outside the forcing region are applied. The localized relaxation is used to dampen Rossby wave propagation to either the west or east of the forcing region and isolate the al...
Security design for a non-standard IPO: The case of SPACs

Abstract A Special Purpose Acquisition Company (SPAC) is a public entity set up by a founder for the specific purpose of acquiring another firm, typically a private firm. The acquired firm is publicly traded after the acquisition, and the acquisition in effect represents a non-standard approach for the private firm to go public. In this paper, we develop a theoretical framework to explain several unique features of the SPAC design such as the prevalence of unit offerings and the use of equity and warrants in the founder's contract. The founder in our model undertakes costly effort to learn about the characteristics of the acquisition target and delivers a good quality firm to the SPAC shareholders. We show that the warrants play a unique role in limiting the level of risk of firms that the founder selects for acquisition. We also show that the equity grant given to the SPAC founder pre-commits the SPAC shareholders and firms to a pre-determined level of underpricing for the non-standard SPAC IPO process.
Wheel-Speed Induced Errors in the Use of Dry-Tuned Gyros

It is known that, for a gimbaled inertial measurement unit employing two dry-tuned gyros, a dual gyro wheel supply (DGWS) gives a better performance than a single gyro wheel supply (SGWS). The effectiveness of the DGWS is explained in this paper by demonstrating the effects of certain vibrations on gyros. It will be shown that a dry-tuned gyro is susceptible to vibrations at frequencies which are either equal to or twice that of the gyro spin frequency. By using two power supplies of slightly different frequencies, external vibrations at these frequencies are avoided. It is recommended that gyro sensitivities with respect to external vibrations at these special frequencies be included in the performance specification of a dry-tuned gyro.
Active immunization of cows with a Salmonella typhimurium mutant bacterin-toxoid and the passive transfer of anti-core-antigen antibodies in colostrum

37 normal Holstein or Guernsey cows in their last 6 weeks of gestation were injected with either a placebo or Salmonella typhimurium mutant bacterin-toxoid. The vaccine stimulated a significant increase in the mean log2 anti-core-antigen serum antibody titres from 10.73 to 12.15 while there was no significant increase in serum antibody titres in placebo treated cows. There was a significant difference between the colostral mean anti-core-antigen antibody log2 titres of the placebo, 12.22, and vaccinated, 13.18, cows. The mean log2, serum antibody titres of suckled calves at 24 h of age from the placebo and vaccinated groups were 9.20 and 10.64 respectively and significantly different. It was concluded that cows vaccinated with bacterin-toxoid in the last 6 weeks of gestation seroconverted in terms of anti-core-antigen antibodies and that they passively transferred significantly higher levels of these antibodies through colostrum to their calves.
Repeated Measures Correlation

Repeated measures correlation (rmcorr) is a statistical technique for determining the common within-individual association for paired measures assessed on two or more occasions for multiple individuals. Simple regression/correlation is often applied to non-independent observations or aggregated data; this may produce biased, specious results due to violation of independence and/or differing patterns between-participants versus within-participants. Unlike simple regression/correlation, rmcorr does not violate the assumption of independence of observations. Also, rmcorr tends to have much greater statistical power because neither averaging nor aggregation is necessary for an intra-individual research question. Rmcorr estimates the common regression slope, the association shared among individuals. To make rmcorr accessible, we provide background information for its assumptions and equations, visualization, power, and tradeoffs with rmcorr compared to multilevel modeling. We introduce the R package (rmcorr) and demonstrate its use for inferential statistics and visualization with two example datasets. The examples are used to illustrate research questions at different levels of analysis, intra-individual, and inter-individual. Rmcorr is well-suited for research questions regarding the common linear association in paired repeated measures data. All results are fully reproducible.
Illusory Late Heavy Bombardments

Abstract The Late Heavy Bombardment (LHB), a hypothesized impact spike at ∼3.9 Ga, is one of the major scientific concepts to emerge from Apollo-era lunar exploration. A significant portion of the evidence for the existence of the LHB comes from histograms of 40Ar/39Ar “plateau” ages (i.e., regions selected on the basis of apparent isochroneity). However, due to lunar magmatism and overprinting from subsequent impact events, virtually all Apollo-era samples show evidence for 40Ar/39Ar age spectrum disturbances, leaving open the possibility that partial 40Ar* resetting could bias interpretation of bombardment histories due to plateaus yielding misleadingly young ages. We examine this possibility through a physical model of 40Ar* diffusion in Apollo samples and test the uniqueness of the impact histories obtained by inverting plateau age histograms. Our results show that plateau histograms tend to yield age peaks, even in those cases where the input impact curve did not contain such a spike, in part due to the episodic nature of lunar crust or parent body formation. Restated, monotonically declining impact histories yield apparent age peaks that could be misinterpreted as LHB-type events. We further conclude that the assignment of apparent 40Ar/39Ar plateau ages bears an undesirably high degree of subjectivity. When compounded by inappropriate interpretations of histograms constructed from plateau ages, interpretation of apparent, but illusory, impact spikes is likely.
Treadmill Exercise Improves Fracture Toughness and Indentation Modulus without Altering the Nanoscale Morphology of Collagen in Mice

The specifics of how the nanoscale properties of collagen (e.g., the crosslinking profile) affect the mechanical integrity of bone at larger length scales is poorly understood despite growing evidence that collagen’s nanoscale properties are altered with disease. Additionally, mass independent increases in postyield displacement due to exercise suggest loading-induced improvements in bone quality associated with collagen. To test whether disease-induced reductions in bone quality driven by alterations in collagen can be rescued or prevented via exercise-mediated changes to collagen’s nanoscale morphology and mechanical properties, the effects of treadmill exercise and β-aminopropionitrile treatment were investigated. Eight week old female C57BL/6 mice were given a daily subcutaneous injection of either 164 mg/kg β-aminopropionitrile or phosphate buffered saline while experiencing either normal cage activity or 30 min of treadmill exercise for 21 consecutive days. Despite differences in D-spacing distribution (P = 0.003) and increased cortical area (tibial: P = 0.005 and femoral: P = 0.015) due to β-aminopropionitrile treatment, an overt mechanical disease state was not achieved as there were no differences in fracture toughness or 4 point bending due to β-aminopropionitrile treatment. While exercise did not alter (P = 0.058) the D-spacing distribution of collagen or prevent (P < 0.001) the β-aminopropionitrile-induced changes present in the unexercised animals, there were differential effects in the distribution of the reduced elastic modulus due to exercise between control and β-aminopropionitrile-treated animals (P < 0.001). Fracture toughness was increased (P = 0.043) as a main effect of exercise, but no significant differences due to exercise were observed using 4 point bending. Future studies should examine the potential for sex specific differences in the dose of β-aminopropionitrile required to induce mechanical effects in mice and the contributions of other nanoscale aspects of bone (e.g., the mineral–collagen interface) to elucidate the mechanism for the exercise-based improvements in fracture toughness observed here and the increased postyield deformation observed in other studies.
Disconnecting structure and dynamics in glassy thin films

Nanometrically thin glassy films depart strikingly from the behavior of their bulk counterparts. We investigate whether the dynamical differences between a bulk and thin film polymeric glass former can be understood by differences in local microscopic structure. Machine learning methods have shown that local structure can serve as the foundation for successful, predictive models of particle rearrangement dynamics in bulk systems. By contrast, in thin glassy films, we find that particles at the center of the film and those near the surface are structurally indistinguishable despite exhibiting very different dynamics. Next, we show that structure-independent processes, already present in bulk systems and demonstrably different from simple facilitated dynamics, are crucial for understanding glassy dynamics in thin films. Our analysis suggests a picture of glassy dynamics in which two dynamical processes coexist, with relative strengths that depend on the distance from an interface. One of these processes depends on local structure and is unchanged throughout most of the film, while the other is purely Arrhenius, does not depend on local structure, and is strongly enhanced near the free surface of a film.
Reasoning with Memory Augmented Neural Networks for Language Comprehension

Hypothesis testing is an important cognitive process that supports human reasoning. In this paper, we introduce a computational hypothesis testing approach based on memory augmented neural networks. Our approach involves a hypothesis testing loop that reconsiders and progressively refines a previously formed hypothesis in order to generate new hypotheses to test. We apply the proposed approach to language comprehension task by using Neural Semantic Encoders (NSE). Our NSE models achieve the state-of-the-art results showing an absolute improvement of 1.2% to 2.6% accuracy over previous results obtained by single and ensemble systems on standard machine comprehension benchmarks such as the Children's Book Test (CBT) and Who-Did-What (WDW) news article datasets.
Univariate and multivariate skewness and kurtosis for measuring nonnormality: Prevalence, influence and estimation

Nonnormality of univariate data has been extensively examined previously (Blanca et al., Methodology: European Journal of Research Methods for the Behavioral and Social Sciences, 9(2), 78-84, 2013; Miceeri, Psychological Bulletin, 105(1), 156, 1989). However, less is known of the potential nonnormality of multivariate data although multivariate analysis is commonly used in psychological and educational research. Using univariate and multivariate skewness and kurtosis as measures of nonnormality, this study examined 1,567 univariate distriubtions and 254 multivariate distributions collected from authors of articles published in Psychological Science and the American Education Research Journal. We found that 74 % of univariate distributions and 68 % multivariate distributions deviated from normal distributions. In a simulation study using typical values of skewness and kurtosis that we collected, we found that the resulting type I error rates were 17 % in a t-test and 30 % in a factor analysis under some conditions. Hence, we argue that it is time to routinely report skewness and kurtosis along with other summary statistics such as means and variances. To facilitate future report of skewness and kurtosis, we provide a tutorial on how to compute univariate and multivariate skewness and kurtosis by SAS, SPSS, R and a newly developed Web application.
Impact Dynamics of a Constrained Mass-Spring-Damper System

This paper discusses the vibration of a mass-spring-damper system with two constraints and impact interactions. Impacting chatter and stuck phenomena for the mass with constraints are investigated and the corresponding conditions for such phenomena are determined. Analytical predictions are presented for the system to give a precise and complete demonstration of the phenomena in the system. Finally, an analytical parameter map is given to show how the system changes with parameters. From these conditions, numerical simulations are performed to demonstrate these phenomena in the system.Copyright © 2012 by ASME
Conditional image synthesis with auxiliary classifier GANs

In this paper we introduce new methods for the improved training of generative adversarial networks (GANs) for image synthesis. We construct a variant of GANs employing label conditioning that results in 128 x 128 resolution image samples exhibiting global coherence. We expand on previous work for image quality assessment to provide two new analyses for assessing the discriminability and diversity of samples from class-conditional image synthesis models. These analyses demonstrate that high resolution samples provide class information not present in low resolution samples. Across 1000 ImageNet classes, 128 x 128 samples are more than twice as discriminable as artificially resized 32 x 32 samples. In addition, 84.7% of the classes have samples exhibiting diversity comparable to real ImageNet data.
Differential Access to Capital from Financial Institutions by Minority Entrepreneurs

This article examines whether minority small business borrowers have the same access to loans from financial institutions as similar white borrowers. Using matching methods, I find that African-American borrowers are rejected at an approximately 30 percent higher probability than similar white borrowers. I also find that the impact of unobservable variables has to be greater than 85 percent the impact of observable variables to show no discrimination. This bound seems to be a high number given that I have controlled for a large number of borrower, firm, and lender characteristics. No such differential effect is found for Asian and other minority borrowers. I also find equal expected default losses between African-American and white borrowers. These results are consistent with the information-based, laissez faire, and group hoarding theories of discrimination, and against the taste-based theory of discrimination.
Machine learning in an auction environment

We consider a model of repeated online auctions in which an ad with an uncertain click-through rate faces a random distribution of competing bids in each auction and there is discounting of payoffs. We formulate the optimal solution to this explore/exploit problem as a dynamic programming problem and show that efficiency is maximized by making a bid for each advertiser equal to the advertiser's expected value for the advertising opportunity plus a term proportional to the variance in this value divided by the number of impressions the advertiser has received thus far. We then use this result to illustrate that the value of incorporating active exploration in an auction environment is exceedingly small.
Impact of six lignocellulosic biochars on C and N dynamics of two contrasting soils

Both soil and biochar properties are known to inﬂuence greenhouse gas emissions from biochar-amended soils, but poor understanding of underlying mechanisms challenges prediction and modeling. Here, we examine the effect of six lignocellulosic biochars produced from the pyrolysis of corn stover and wood feedstocks on CO(2) and N(2)O emissions from soils collected from two bioenergy cropping systems. Effects of biochar on total accumulated C(O)2-C emissions were minimal (<0.45 mg C g1 soil; <10% of biochar C), consistent with mineralization and hydrolysis of small labile organic and inorganic C fractions in the studied biochars. Comparisons of soil C(O)2 emissions with emissions from microbially inoculated quartz–biochar mixtures (‘quartz controls’) provide evidence of soil and biochar-speciﬁc negative priming. Five of six biochar amendments suppressed N(2)O emissions from at least one soil, and the magnitude of N(2)O emissions suppression varied with respect to both biochar and soil types. Biochar amendments consistently decreased ﬁnal soil NO(3) concentrations, while contrasting effects on pH, NH4+, and DOC highlighted the potential for formation of anaerobic microsites in biochar-amended soils and consequential shifts in the soil redox environment. Thus, results implicated both reduced substrate availability and redox shifts as potential factors contributing to N(2)O emission suppression. More research is needed to conﬁrm these mechanisms, but overall our results suggest that soil biochar amendments commonly reduce N(2)O emissions and have little effect on CO(2) emissions beyond the mineralization and/ or hydrolysis of labile biochar C fractions. Considering the large C credit for the biochar C, we conclude that biochar amendments can reduce greenhouse gas emissions and enhance the climate change mitigation potential of bioenergy cropping systems.
2D CFT partition functions at late times

We consider the late time behavior of the analytically continued partition function Z(β + it)Z(β − it) in holographic 2d CFTs. This is a probe of information loss in such theories and in their holographic duals. We show that each Virasoro character decays in time, and so information is not restored at the level of individual characters. We identify a universal decaying contribution at late times, and conjecture that it describes the behavior of generic chaotic 2d CFTs out to times that are exponentially large in the central charge. It was recently suggested that at sufficiently late times one expects a crossover to random matrix behavior. We estimate an upper bound on the crossover time, which suggests that the decay is followed by a parametrically long period of late time growth. Finally, we discuss gravitationally-motivated integrable theories and show how information is restored at late times by a series of characters. This hints at a possible bulk mechanism, where information is restored by an infinite sum over non-perturbative saddles.
Pop-up SLAM: Semantic monocular plane SLAM for low-texture environments

Existing simultaneous localization and mapping (SLAM) algorithms are not robust in challenging low-texture environments because there are only few salient features. The resulting sparse or semi-dense map also conveys little information for motion planning. Though some work utilize plane or scene layout for dense map regularization, they require decent state estimation from other sources. In this paper, we propose real-time monocular plane SLAM to demonstrate that scene understanding could improve both state estimation and dense mapping especially in low-texture environments. The plane measurements come from a pop-up 3D plane model applied to each single image. We also combine planes with point based SLAM to improve robustness. On a public TUM dataset, our algorithm generates a dense semantic 3D model with pixel depth error of 6.2 cm while existing SLAM algorithms fail. On a 60 m long dataset with loops, our method creates a much better 3D model with state estimation error of 0.67%.
Calculating phase-coherent quantum transport in nanoelectronics with ab initio quasiatomic orbital basis set

We present an efficient and accurate computational approach to study phase-coherent quantum transport in molecular and nanoscale electronics. We formulate a Green's-function method in the recently developed ab initio nonorthogonal quasiatomic orbital basis set within the Landauer-B\"uttiker formalism. These quasiatomic orbitals are efficiently and robustly transformed from Kohn-Sham eigenwave functions subject to the maximal atomic-orbital similarity measure. With this minimal basis set, we can easily calculate electrical conductance using Green's-function method while keeping accuracy at the level of plane-wave density-functional theory. Our approach is validated in three studies of two-terminal electronic devices, in which projected density of states and conductance eigenchannel are employed to help understand microscopic mechanism of quantum transport. We first apply our approach to a seven-carbon atomic chain sandwiched between two finite cross-sectioned Al(001) surfaces. The emergence of gaps in the conductance curve originates from the selection rule with vanishing overlap between symmetry-incompatible conductance eigenchannels in leads and conductor. In the second application, a (4,4) single-wall carbon nanotube with a substitutional silicon impurity is investigated. The complete suppression of transmission at 0.6 eV in one of the two conductance eigenchannels is attributed to the Fano antiresonance when the localized silicon impurity state couples with the continuum states of carbon nanotube. Finally, a benzene-1,4-dithiolate molecule attached to two Au(111) surfaces is considered. Combining fragment molecular orbital analysis and conductance eigenchannel analysis, we demonstrate that conductance peaks near the Fermi level result from resonant tunneling through molecular orbitals of benzene-1,4-dithiolate molecule. In general, our conductance curves agree very well with previous results obtained using localized basis sets while slight difference is observed near the Fermi level and conductance edges.
What Do Learning Scientists Do? A Survey of the ISLS Membership

This study responds to a question that people working in the field of learning sciences get asked regularly: What do learning scientists do? Earlier attempts to answer this question came from a need to define a new field of educational research. Now that the International Society of the Learning Sciences (ISLS) has grown into a robust and productive society, it is time to gain a more nuanced understanding of learning sciences research and practices—including where it takes place, for whom, and in what form—as defined by members of the learning sciences community. Here we report on the responses of 253 ISLS members to a survey conducted in 2014. We discuss implications of the findings in terms of the type of impact learning scientists have. We also discuss how these results might be used to advise prospective students and to create a vision for our future.
Random contractions and sampling for hypergraph and hedge connectivity

We initiate the study of hedge connectivity of undirected graphs, motivated by dependent edge failures in real-world networks. In this model, edges are partitioned into groups called hedges that fail together. The hedge connectivity of a graph is the minimum number of hedges whose removal disconnects the graph. We give a polynomial-time approximation scheme and a quasi-polynomial exact algorithm for hedge connectivity. This provides strong evidence that the hedge connectivity problem is tractable, which contrasts with prior work that established the intractability of the corresponding s−t min-cut problem. Our techniques also yield new combinatorial and algorithmic results in hypergraph connectivity. Next, we study the behavior of hedge graphs under uniform random sampling of hedges. We show that unlike graphs, all cuts in the sample do not converge to their expected value in hedge graphs. Nevertheless, the min-cut of the sample does indeed concentrate around the expected value of the original min-cut. This leads to a sharp threshold on hedge survival probabilities for graph disconnection. To the best of our knowledge, this is the first network reliability analysis under dependent edge failures.
Experimental evaluation of a negative-ion source for a heavy-ion fusion negative-ion driver

Abstract Negative halogen ions have recently been proposed as a possible alternative to positive ions for heavy-ion fusion drivers because electron accumulation would not be a problem in the accelerator, and if desired, the beams could be photodetached to neutrals (Nucl. Instr. and Meth. A 464 (2001) 315; Fusion Sci. Technol. 43 (2003) 191; Laser Part. Beams 21 (2003) 545). To test the ability to make suitable quality beams, an experiment was conducted at Lawrence Berkeley National Laboratory using chlorine in an RF-driven ion source. Without introducing any cesium (which is required to enhance negative ion production in hydrogen ion sources) a negative chlorine current density of 45 mA/cm 2 was obtained under the same conditions that gave 57 mA/cm 2 of positive chlorine, suggesting the presence of nearly as many negative ions as positive ions in the plasma near the extraction plane. The negative-ion spectrum was 99.5% atomic chlorine ions, with only 0.5% molecular chlorine, and essentially no impurities. Although this experiment did not incorporate the type of electron suppression technology that is used in negative hydrogen beam extraction, the ratio of co-extracted electrons to Cl − was as low as 7 to 1, many times lower than the ratio of their mobilities, suggesting that few electrons are present in the near-extractor plasma. This, along with the near-equivalence of the positive- and negative-ion currents, suggests that the plasma in this region was mostly an ion–ion plasma. The negative chlorine current density was relatively insensitive to pressure, and scaled linearly with RF power. If this linear scaling continues to hold at higher RF powers, it should permit current densities of 100 mA/cm 2 , sufficient for present heavy-ion fusion injector concepts. The effective ion temperatures of the positive and negative ions appeared to be similar and relatively low for a plasma source.
Synthesis and alkali metal picrate extraction capabilities of novel, cage-functionalized diaza(17-crown-5) ethers

Abstract The syntheses of novel cage-annulated diaza (17-crown-5) lariat crown ethers, i.e.,10–16 are reported. A series of alkali metal picrate extraction experiments have been performed by using this new class of synthetic ionophores in order to evaluate the effects of cage-annulation and the influence ofN-pivotside-arms upon complexation properties. The results thereby obtained indicate that complexation of these lariat crown ethers with alkali metal cations is influenced by both of these structural features. In particular, the cage-annulated diaza crown ether11 displays much greater avidity toward all alkali metal cations studied than does the corresponding model system (1). It was observed that ligands11 and13 display bimodal behavior toward extraction of alkali metal picrates, whereas ligands15 and16 behave as relatively non-selective alkali metal picrate extractants. A cage-annulated cryptand,19, was prepared, and its alkali metal picrate extraction profile was obtained. Highly preorganized cryptand19 displays particularly high avidity toward complexation of K+ and Rb+ picrates in solution. The syntheses and alkali metal picrate extraction profiles of several new crown ethers (11, 13, 15, and16) and a novel, cage-functionalized cryptand (19) are described. Download : Download full-size image
Observed asteroid surface area in the thermal infrared

The rapid accumulation of thermal infrared observations and shape models of asteroids has led to increased interest in thermophysical modeling. Most of these infrared observations are unresolved. We consider what fraction of an asteroid's surface area contributes the bulk of the emitted thermal flux for two model asteroids of different shapes over a range of thermal parameters. The resulting observed surface in the infrared is generally more fragmented than the area observed in visible wavelengths, indicating high sensitivity to shape. For objects with low values of the thermal parameter, small fractions of the surface contribute the majority of thermally emitted flux. Calculating observed areas could enable the production of spatially resolved thermal inertia maps from non-resolved observations of asteroids.
Coral Reefs in Crisis: The Reliability of Deep-Time Food Web Reconstructions as Analogs for the Present

Ongoing anthropogenic alterations of the biosphere have shifted emphasis in conservation biology from individual species to entire ecosystems. Modern measures of ecosystem change, however, lack the extended temporal scales necessary to forecast future change under increasingly stressful environmental conditions. Accordingly, the assessment and reconstruction of ecosystem dynamics during previous intervals of environmental stress and climate change in deep time has garnered increasing attention. The nature of the fossil record, though, raises questions about the difficulty of reconstructing paleocommunity and paleoecosystem-level dynamics. In this study, we assess the reliability of such reconstructions by simulating the fossilization of a highly threatened and disturbed modern ecosystem, a Caribbean coral reef. Using a high-resolution coral reef food web from Jamaica, we compare system structures of the modern and simulated fossil reefs, including guild richness and evenness, trophic level distribution, predator dietary breadth, food chain lengths, and modularity. Results indicate that despite the loss of species, guilds, and trophospecies interactions, particularly zooplankton and other soft-bodied organisms, the overall guild diversity, structure, and modularity of the reef ecosystem remained intact. These results have important implications for the integrity of fossil food web studies and coral reef conservation, demonstrating that fossil reef communities can be used to understand reef community dynamics during past regimes of environmental change.
Asymmetric exchange between electron spins in coupled semiconductor quantum dots

We obtain a microscopic description of the interaction between electron spins in bulk semiconductors and in pairs of semiconductor quantum dots. Treating the k.p band mixing and the Coulomb interaction on the same footing, we obtain in the third order an asymmetric contribution to the exchange interaction arising from the coupling between the spin of one electron and the relative orbital motion of the other. This contribution does not depend on the inversion asymmetry of the crystal. We find that it is ~0.001 of the isotropic exchange, which is of interest in quantum information. Detailed evaluations are given for several quantum dot systems.
No compromise: Uncertain costs in reputational bargaining

Abstract I show how uncertainty about agents' future costs of delay can lead to substantial bargaining delays when agents have reputational concerns. Reputational concerns arise because with positive probability agents are behavioral types, committed to demanding a fixed share of the surplus. In equilibrium, rational agents may demand almost the entire surplus and then wait, with the deadlock only broken by the arrival of news about future costs, even as the probability of behavioral types vanishes. Although both agents would benefit from a compromise reached immediately, they do not propose such agreements, because doing so would increase an opponent's option value of waiting.
Ion parallel closures

Ion parallel closures are obtained for arbitrary atomic weights and charge numbers. For arbitrary collisionality, the heat flow and viscosity are expressed as kernel-weighted integrals of the temperature and flow-velocity gradients. Simple, fitted kernel functions are obtained from the 1600 parallel moment solution and the asymptotic behavior in the collisionless limit. The fitted kernel parameters are tabulated for various temperature ratios of ions to electrons. The closures can be used conveniently without solving the kinetic equation or higher order moment equations in closing ion fluid equations.
Determination of nonlinear genetic architecture using compressed sensing

One of the fundamental problems of modern genomics is to extract the genetic architecture of a complex trait from a data set of individual genotypes and trait values. Establishing this important connection between genotype and phenotype is complicated by the large number of candidate genes, the potentially large number of causal loci, and the likely presence of some nonlinear interactions between different genes. Compressed Sensing methods obtain solutions to under-constrained systems of linear equations. These methods can be applied to the problem of determining the best model relating genotype to phenotype, and generally deliver better performance than simply regressing the phenotype against each genetic variant, one at a time. We introduce a Compressed Sensing method that can reconstruct nonlinear genetic models (i.e., including epistasis, or gene-gene interactions) from phenotype-genotype (GWAS) data. Our method uses L1-penalized regression applied to nonlinear functions of the sensing matrix. The computational and data resource requirements for our method are similar to those necessary for reconstruction of linear genetic models (or identification of gene-trait associations), assuming a condition of generalized sparsity, which limits the total number of gene-gene interactions. An example of a sparse nonlinear model is one in which a typical locus interacts with several or even many others, but only a small subset of all possible interactions exist. It seems plausible that most genetic architectures fall in this category. We give theoretical arguments suggesting that the method is nearly optimal in performance, and demonstrate its effectiveness on broad classes of nonlinear genetic models using simulated human genomes and the small amount of currently available real data. A phase transition (i.e., dramatic and qualitative change) in the behavior of the algorithm indicates when sufficient data is available for its successful application. Our results indicate that predictive models for many complex traits, including a variety of human disease susceptibilities (e.g., with additive heritability h 2∼0.5), can be extracted from data sets comprised of n ⋆∼100s individuals, where s is the number of distinct causal variants influencing the trait. For example, given a trait controlled by ∼10 k loci, roughly a million individuals would be sufficient for application of the method.