cssi/SciSciGPT-SciSciNet huggingface dataset:
RedTweet: recommendation engine for reddit

Twitter and Reddit are two of the most popular social media sites used today. In this paper, we study the use of machine learning and WordNet-based classifiers to generate an interest profile from a user's tweets and use this to recommend loosely related Reddit threads which the reader is most likely to be interested in. We introduce a genre classification algorithm using a similarity measure derived from WordNet lexical database for English to label genres for nouns in tweets. The proposed algorithm generates a user's interest profile from their tweets based on a referencing taxonomy of genres derived from the genre-tagged Brown Corpus augmented with a technology genre. The top K genres of a user's interest profile can be used for recommending subreddit articles in those genres. Experiments using real life test cases collected from Twitter have been done to compare the performance on genre classification by using the WordNet classifier and machine learning classifiers such as SVM, Random Forests, and an ensemble of Bayesian classifiers. Empirically, we have obtained similar results from the two different approaches with a sufficient number of tweets. It seems that machine learning algorithms as well as the WordNet ontology are viable tools for developing recommendation engine based on genre classification. One advantage of the WordNet approach is simplicity and no learning is required. However, the WordNet classifier tends to have poor precision on users with very few tweets.
Improved Thermal Transfer Efficiency for Planar Solar Thermophotovoltaic Devices

Solar thermophotovoltaic (STPV) devices provide conversion of solar energy to electrical energy through the use of an intermediate absorber/emitter module, which converts the broad solar spectrum to a tailored spectrum that is emitted towards a photovoltaic cell [1]. While the use of an absorber/emitter device could potentially overcome the Shockley-Queisser limit of photovoltaic conversion [2], it also increases the number of heat loss mechanisms. One of the most prohibitive aspects of STPV conversion is the thermal transfer efficiency, which is a measure of how well solar energy is delivered to the emitter. Although reported thermophotovoltaic efficiencies (thermal to electric) have exceeded 10% [3], [4], previously measured STPV conversion efficiencies are below 1% [5], [6], [7].In this work, we present the design and characterization of a nanostructured absorber for use in a planar STPV device with a high emitter-to-absorber area ratio. We used a process for spatially-selective growth of vertically aligned multi-walled carbon nanotube (MWCNT) forests on highly reflective, smooth tungsten (W) surfaces. We implemented these MWCNT/W absorbers in a TPV system with a one-dimensional photonic crystal emitter, which was spectrally paired with a low bandgap PV cell. A high fidelity, system-level model of the radiative transfer in the device was experimentally validated and used to optimize the absorber surface geometry. For an operating temperature of approximately 1200 K, we experimentally demonstrated a 100% increase in overall STPV efficiency using a 4 to 1 emitter-to-absorber area ratio (relative to a 1 to 1 area ratio), due to improved thermal transfer efficiency. By further increasing the solar concentration incident on the absorber surface, increased emitter-to-absorber area ratios will improve both thermal transfer and overall efficiencies for these planar devices.© 2013 ASME
A spiro-linked pyrene-naphthoquinone.

The title mol­ecule, 2′-pyrenyl­spiro­[2,3-di­hydro-1H-cyclo­penta­[b]­naphthalene-2,5′-1′,3′-dioxane]-4,9-dione, C32H22O4, contains an electron-donating pyrene group spiro-linked to an electron-accepting naphtho­quinone. The mol­ecules are V-shaped in profile and stack to form columns along b with alternating, approximately coplanar, pyrene and naphtho­quinone fragments. Intermolecular contacts within a column are consistent with some degree of π contact and possible long-range delocalization. Individual columns form a herringbone pattern when the crystal is viewed along b.
How do our new graduates prefer to learn

Background: Learning preference refers to one's choice of specific learning situations or environments over the other. It is one of the factors needed to be considered in planning curriculum and in designing instructional units. Objectives: The primary objectives of this study were to characterize the learning preference of recent medical graduates of the National University of Singapore (NUS) and to identify any possible gender differences.This study is likely to be first of its kind in this learner population. Instrument: Rezler's Learning Preference Inventory. Methods: Rezler's Learning Preference Inventory was administered among twenty-eight 1997 graduates (male 16, female 12) of NUS. The independent variable was the gender and the dependent variables were the scores in each of the learning categories: abstract, concrete, teacher-structured, student-structured, interpersonal, and independent. Analysis: Frequency distribution of the learning preferences was counted manually. Independent samples t-test was used to compare two groups of dependent variables. Results: Ninety-two percent female and sixty-nine percent male respondents preferred concrete learning. Only one male respondent and none of the female respondents preferred abstract learning. Among all the respondents, differences between concrete and abstract categories reached statistical, as well as meaningful, significance (p < 0.0001 and mean score difference of 19.9). Differences between student-structured and teacher-structured, and between interpersonal and independent categories did not reach statistical significance (p value of 0.5l and 0.78 respectively). Female respondents generally showed a trend towards greater preference for concrete and teacher-structured learning than their male counterparts. Conclusion: The learning preferences of recent graduates of the NUS is characterized by high inclination towards concrete learning.The results can be utilized in designing instructional methods for this group of learners.
Management of Urethral Stricture Disease

With the advent of modern tissue transfer techniques, most cases of urethral reconstruction can be approached with confidence that an excellent functional and cosmetic result is probable. The authors present a logical approach to urethral stricture disease predicated on the anatomy of the stricture disease. Only those procedures believed to offer a maximal chance of success are offered to the patients. Should a patient present with complex stricture disease, initially a flap procedure would be employed.
Voronoi binding site models.

compounds to the same site are known, but the geometry and energetic interactions of the site are not. This paper presents in detail a novel approach to the problem which accurately but compactly represents the allowed conformation space of each ligand, accurately depicts their three-dimensional structures, and realistically allows each ligand to adopt the conformation and positioning in the site which is most favorable energetically. The investigator supplies only the ligand structures and observed binding free energies, along with a proposed site geometry. With no further assumptions about how the ligands bind and what parts of the ligands are important in determining the binding, the algorithm fits the observed binding energies without leaving outliers, predicts exactly how each of the given ligands binds in the site, and predicts the strength and mode of binding of new compounds, regardless of chemical similarity to the original set of ligands. The method is illustrated by devising a simple site that accounts for the binding of five polychlorinated biphenyls to thyroxine binding prealbumin. This model then predicts the binding energies correctly for an additional six biphenyls, and fails on one compound.
Free radical theory of aging.

Aging is the accumulation of changes responsible for both the sequential alterations that accompany advancing age and the associated progressive increases in the chance of disease and death. The production of these changes can be attributed to the environment and disease and to an inborn aging process (es). Past improvements in general living conditions have decreased the chances for death so that they are now near limiting values in the developed countries. In these countries the aging process is the major cause of disease and death after about age 28. The free radical theory of aging postulates that aging changes are caused by free radical reactions. Support for this theory is extensive; it includes: 1) studies on the origin and evolution of life, 2) studies of the effect of ionizing radiation on living things, 3) dietary manipulation of endogenous free radical reactions, 4) the plausible explanation it provides for aging phenomena, and 5) the growing number of studies that implicate free radical reactions in the pathogenesis of specific diseases. On the basis of present data the healthy active life span may be increased by 5-10 or more years by keeping body weight down, at a level compatible with a sense of well-being while ingesting diets adequate in essential nutrients but designed to minimize random free radical reactions in the body.
Use the SPT to Measure Dynamic Soil Properties?—Yes, But..!

The author briefly reviews the factors important to the blowcount (N) values obtained from the standard penetration test (SPT), and describes the dynamics of the SPT in terms of wave transmission theory and measurements. The SPT appears to correlate well qualitatively with sand liquefaction potential, with N proportional to the factor of safety against liquefaction. The SPT can also provide the basis for the field-model determination of the J, and J p damping coefficients in the wave equation analysis of pile-driving problems. An example indicates it may also correlate locally with shear wave velocity in sands. Because of its current variability, however, the profession needs an improved, possibly alternative ASTM standard before we use the SPT in important dynamic design problems. The author suggests using a mechanized hammer drop system producing a fixed energy content in the first compression wave in the rods, and the use of rotary drilling with the hole filled with drilling mud at all times.
PVCO Pipeline Performance Under Large Ground Deformation

Technological advances have improved pipeline capacity to accommodate large ground deformation associated with earthquakes, floods, landslides, tunneling, deep excavations, mining, and subsidence. The fabrication of polyvinyl chloride (PVC) piping, for example, can be modified by expanding PVC pipe stock to approximately twice its original diameter, thus causing PVC molecular chains to realign in the circumferential direction. This process yields biaxially oriented polyvinyl chloride (PVCO) pipe with increased circumferential strength, reduced pipe wall thickness, and enhanced cross-sectional flexibility.This paper reports on experiments performed at the Cornell University Large-Scale Lifelines Testing Facility characterizing PVCO pipeline performance in response to large ground deformation. The evaluation was performed on 150-mm (6-in.)-diameter PVCO pipelines with bell-and-spigot joints. The testing procedure included determination of fundamental PVCO material properties, axial joint tension and compression tests, four-point bending tests, and a full-scale fault rupture simulation. The test results show the performance of segmental PVCO pipelines under large ground deformation is strongly influenced by the axial pullout and compressive load capacity of the joints, as well as their ability to accommodate deflection and joint rotation. The PVCO pipeline performance is quantified in terms of its capacity to accommodate horizontal ground strain, and compared with a statistical characterization of lateral ground strains caused by soil liquefaction during the Canterbury earthquake sequence in New Zealand.Copyright © 2015 by ASME
A hierarchical multiprocessor bandwidth reservation scheme with timing guarantees

A multiprocessor scheduling scheme is presented for supporting hierarchical containers that encapsulate sporadic soft and hard real-time tasks. In this scheme, each container is allocated a specified bandwidth, which it uses to schedule its children (some of which may also be containers). This scheme is novel in that, with only soft real-time tasks, no utilization loss is incurred when provisioning containers, even in arbitrarily deep hierarchies. Presented experiments show that the proposed scheme performs well compared to conventional real-time scheduling techniques that do not provide container isolation.
The Investment Function

The theory discussed in Chapter 4, on the production function, can also form the basis of a study of the demand for labour and the demand for capital, whether the equipment, structures, inventory, or cash of business firms, as well as, by stretching a point, the demand for consumer durables, including especially that for housing. We may, for businesses at least, assume a profit-maximizing neoclassical aggregate firm and investigate its optimal capital and labour decisions; we may also adopt a cost-minimization framework, and this is often recommended on account of its ease of manipulation (and the existence of certain types of data). Note that we get from the profit/cost framework to the investment decision of the aggregate firm by introducing some explicit dynamics involving both (a) a formal stock flow dimension and (b) lags in decision-making and in implementing capital spending (once decisions to invest have been made). These matters will be taken up in Section 5.3, after we have considered some of the work prior to the synthesis now in common use; this latter may be referred to as a “neoclassical investment function” with a “flexible accel-erator” mechanism.
The Association Between Sexual Health and Physical, Mental, and Social Health in Adolescent Women.

Abstract Purpose Developmental models link sexual well-being to physical, mental/emotional, and social well-being, yet little empirical literature evaluates these relationships in adolescents. Better understanding of how and when sexuality complements other aspects of health may yield important points to enhance existing health education and prevention efforts. Methods Data were drawn from a 10-year longitudinal cohort study of sexual relationships and sexual behavior among adolescent women (N = 387; 14–17 years at enrollment). Sexual health data were drawn from quarterly partner-specific interviews and were linked to physical, mental/emotional, and social health information in annual questionnaires. Random intercept, mixed effects linear, ordinal logistic, or binary logistic regression were used to estimate the influence of sexual health on health and well-being outcomes (Stata, v.23, StataCorp, College Station, TX). All models controlled for participant age and race/ethnicity. Results Higher sexual health was significantly associated with less frequent nicotine and substance use, lower self-reported depression, lower thrill seeking, higher self-esteem, having fewer friends who use substances, higher religiosity, better social integration, lower frequency of delinquent behavior and crime, and more frequent community group membership. Sexual health was not associated with the number of friends who used cigarettes. Conclusions Positive sexually related experiences in romantic relationships during adolescence may complement physical, mental/emotional, and social health. Addressing specific aspects of healthy sexual development during clinical encounters could dually help primary prevention and health education address other common adolescent health issues.
Adaptation in protein fitness landscapes is facilitated by indirect paths

The structure of fitness landscapes is critical for understanding adaptive protein evolution. Previous empirical studies on fitness landscapes were confined to either the neighborhood around the wild type sequence, involving mostly single and double mutants, or a combinatorially complete subgraph involving only two amino acids at each site. In reality, the dimensionality of protein sequence space is higher (20(L)) and there may be higher-order interactions among more than two sites. Here we experimentally characterized the fitness landscape of four sites in protein GB1, containing 20(4) = 160,000 variants. We found that while reciprocal sign epistasis blocked many direct paths of adaptation, such evolutionary traps could be circumvented by indirect paths through genotype space involving gain and subsequent loss of mutations. These indirect paths alleviate the constraint on adaptive protein evolution, suggesting that the heretofore neglected dimensions of sequence space may change our views on how proteins evolve.
Ethnogenomics: The societies that rubber built.

The rubber tree Hevea brasiliensis has a chequered and little-understood social history underlying its status as one of the world's most useful plants. Anthropological insight into its history can help to tackle the challenges rubber production will face in the future.
The future of distribution systems in the deregulated environment: opportunities and challenges

Summary form only given. In the past, distribution systems have not received as much attention as generation and transmission systems. Restructuring of the electric utility industry is causing widespread changes in the power distribution sector. The growing needs of individual customers and the innovative technologies being developed to meet such requirements coupled with regulatory supervision are the driving forces that are bringing about a new revolution in distribution systems. Distribution engineers need to re-orient their thinking and approach to meet fast-changing demands being imposed on them. Distribution companies must be flexible in order to compete efficiently and effectively with their competitors. Only then can systems be optimally designed and operated. Without innovative thinking, power delivery systems, and, in particular, distribution systems will cease to exist and independent, individually owned customer systems will emerge instead. In the first part of this presentation, the changes taking place due to deregulation are delineated. The second part focuses on identifying opportunities and challenges resulting from these changes.
The Effects of Population Size Histories on Estimates of Selection Coefficients from Time-Series Genetic Data

Many approaches have been developed for inferring selection coefficients from time series data while accounting for genetic drift. These approaches have been motivated by the intuition that properly accounting for the population size history can significantly improve estimates of selective strengths. However, the improvement in inference accuracy that can be attained by modeling drift has not been characterized. Here, by comparing maximum likelihood estimates of selection coefficients that account for the true population size history with estimates that ignore drift by assuming allele frequencies evolve deterministically in a population of infinite size, we address the following questions: how much can modeling the population size history improve estimates of selection coefficients? How much can mis-inferred population sizes hurt inferences of selection coefficients? We conduct our analysis under the discrete Wright-Fisher model by deriving the exact probability of an allele frequency trajectory in a population of time-varying size and we replicate our results under the diffusion model. For both models, we find that ignoring drift leads to estimates of selection coefficients that are nearly as accurate as estimates that account for the true population history, even when population sizes are small and drift is high. This result is of interest because inference methods that ignore drift are widely used in evolutionary studies and can be many orders of magnitude faster than methods that account for population sizes.
Modeling of reduced effective secondary electron emission yield from a velvet surface

Complex structures on a material surface can significantly reduce total secondary electron emission from that surface. A velvet is a surface that consists of an array of vertically standing whiskers. The reduction occurs due to the capture of low-energy, true secondary electrons emitted at the bottom of the structure and on the sides of the velvet whiskers. We performed numerical simulations and developed an approximate analytical model that calculates the net secondary electron emission yield from a velvet surface as a function of the velvet whisker length and packing density, and the angle of incidence of primary electrons. We found that to suppress secondary electrons, the following condition on dimensionless parameters must be met: (π/2)DA tan θ≫1, where θ is the angle of incidence of the primary electron from the normal, D is the fraction of surface area taken up by the velvet whisker bases, and A is the aspect ratio, A ≡ h/r, the ratio of height to radius of the velvet whiskers. We find that velvets...
RESIDUAL FLEXION CONTRACTURES: THE THING I LEFT BEHIND

Flexion contractures are a common finding in an end-stage arthritic knee, occurring in up to 60% of patients undergoing total knee arthroplasty. Fixed flexion deformities may result from posterior capsular scarring, osteophyte formation, and bony impingement. It is essential to correct this deformity at the time of total knee arthroplasty, as a residual flexion contracture will result in joint overload and abnormal gait mechanics. This may translate to a slower walking velocity, shorter stride length, and pain. This presentation will discuss a systematic way of dealing with flexion contractures to ensure that the total knee arthroplasty will achieve full extension. The surgical technique for treating fixed flexion deformity about the knee includes release of the posterior cruciate ligament, posterior capsular release, adequate distal femoral bone resection, and removal of osteophytes. Post-operatively, attention must be divided between obtaining maximal flexion and full extension. Should a flexion contracture be noted upon the post-operative visit, additional measures should be taken to address it.
A NEW ASYMPTOTIC DIFFUSION THEORY

The variational formalism is used to derive from the monoenergetic Boltzmann equation a diffusion theory with the asymptotic transport diffusion coefficient. By considering an interface between two...
A modern approach to superradiance

In this paper, we provide a simple and modern discussion of rotational super-radiance based on quantum field theory. We work with an effective theory valid at scales much larger than the size of the spinning object responsible for superradiance. Within this framework, the probability of absorption by an object at rest completely determines the superradiant amplification rate when that same object is spinning. We first discuss in detail superradiant scattering of spin 0 particles with orbital angular momentum l = 1, and then extend our analysis to higher values of orbital angular momentum and spin. Along the way, we provide a simple derivation of vacuum friction — a “quantum torque” acting on spinning objects in empty space. Our results apply not only to black holes but to arbitrary spinning objects. We also discuss superradiant instability due to formation of bound states and, as an illustration, we calculate the instability rate Γ for bound states with massive spin 1 particles. For a black hole with mass M and angular velocity Ω, we find Γ ∼ (GM μ)7Ω when the particle’s Compton wavelength 1/μ is much greater than the size GM of the spinning object. This rate is parametrically much larger than the instability rate for spin 0 particles, which scales like (GM μ)9Ω. This enhanced instability rate can be used to constrain the existence of ultralight particles beyond the Standard Model.
Towards the design of prospect-theory based human decision rules for hypothesis testing

Detection rules have traditionally been designed for rational agents that minimize the Bayes risk (average decision cost). With the advent of crowd-sensing systems, there is a need to redesign binary hypothesis testing rules for behavioral agents, whose cognitive behavior is not captured by traditional utility functions such as Bayes risk. In this paper, we adopt prospect theory based models for decision makers. We consider special agent models namely optimists and pessimists in this paper, and derive optimal detection rules under different scenarios. Using an illustrative example, we also show how the decision rule of a human agent deviates from the Bayesian decision rule under various behavioral models, considered in this paper.
What do a bank’s legal expenses reveal about its internal controls and operational risk?

Abstract Excessive (substantially above peer) litigation against a bank is indicative of operational risk because it often suggests failure to maintain a strong system of internal control. We examine the relation between bank performance and weak internal control using legal expense as a proxy. We find that legal expense is a strong determinant of loan losses and stock returns. Bank regulators should require reporting of legal expense on call reports to help identify institutions with weaknesses in internal control. Current reporting creates unnecessary information asymmetries because investors are not well informed about operational risk, leading to mispricing of bank securities.
Averaged null energy condition from causality

Unitary, Lorentz-invariant quantum field theories in flat spacetime obey mi-crocausality: commutators vanish at spacelike separation. For interacting theories in more than two dimensions, we show that this implies that the averaged null energy, ∫ duT uu , must be non-negative. This non-local operator appears in the operator product expansion of local operators in the lightcone limit, and therefore contributes to n-point functions. We derive a sum rule that isolates this contribution and is manifestly positive. The argument also applies to certain higher spin operators other than the stress tensor, generating an infinite family of new constraints of the form ∫ duX uuu···u ≥ 0. These lead to new inequalities for the coupling constants of spinning operators in conformal field theory, which include as special cases (but are generally stronger than) the existing constraints from the lightcone bootstrap, deep inelastic scattering, conformal collider methods, and relative entropy. We also comment on the relation to the recent derivation of the averaged null energy condition from relative entropy, and suggest a more general connection between causality and information-theoretic inequalities in QFT.
Data Structures and Algorithms for Packet Forwarding and Classification

Efficient packet forwarding is central to moving traffic smoothly through the Internet. For example, at a line rate of 10Gbps and a minimum packet size of 40 bytes, an Internet router must process more than 30 million packets per second. At 80Gbps, more than240 million packets must be processed per second. At its simplest, packet processing involves extracting the packet’s destination address, doing a look up in a router table of size up to about 1 million, and sending the packet to its next hop as determined by the table lookup. Besides providing a very high look up rate, an Internet router must be able to update its lookup table at rates that are of the order of 50,000 updates per second (peak). The extreme performance demand on an Internet router may be somewhat reduced by maintaining an additional flow table, filtering out packets that correspond to a packet in the flow table, and doing a router table lookup only for those packets that do not correspond to an existing flow [3]. Power consumption is another very important consideration in the design of an Internet router. For example, Sekiguchi [6]projects that with a 40% annual growth in Internet traffic, the energy consumed by routers in Japan in 2022 will exceed the 2005gross power generation of Japan. Extensive research has been conducted to develop good data structures to meet the lookup and update requirements of a router as well as to reduce power consumption. This talk reviews some of this research as well as current trends in router design. Sample data structures include multibit one- and two-dimensional tries and hybrid shape shifting tries. Hardware assisted solutions such as Ternary Content Addressable Memories also are reviewed. For more details, see the listed references.
SMERED: A Bayesian Approach to Graphical Record Linkage and De-duplication

We propose a novel unsupervised approach for linking records across arbitrarily many files, while simultaneously detecting duplicate records within files. Our key innovation is to represent the pattern of links between records as a bipartite graph, in which records are directly linked to latent true individuals, and only indirectly linked to other records. This flexible new representation of the linkage structure naturally allows us to estimate the attributes of the unique observable people in the population, calculate k-way posterior probabilities of matches across records, and propagate the uncertainty of record linkage into later analyses. Our linkage structure lends itself to an ecient, linear-time, hybrid Markov chain Monte Carlo algorithm, which overcomes many obstacles encountered by previously proposed methods of record linkage, despite the high dimensional parameter space. We assess our results on real and simulated data.
Batch transfer of LIGA microstructures by selective electroplating and bonding

A flip-chip batch transfer process for LIthographie, Galvanoformung and Abformung (LIGA) microstructures has been demonstrated by selective electroplating and bonding. Single layer LIGA microstructures with thickness of 200 /spl mu/m are fabricated on a dummy substrate first. They are then batch transferred to an IC substrate by means of bonding via electroplating. After the selective bonding process, the originally fixed microstructures become free-standing, moveable devices. The electroplating and bonding process is conducted at 50/spl deg/C with applied electroplating current density at 68.3 AM/sup 2/ and it takes about 80 minutes to complete the bonding process. Experimentally, an electrothermally-driven LIGA microgripper has been demonstrated to operate after the batch transfer process. When a maximum input current of 1.6 amp is applied, the tip of the microgripper moves 92 /spl mu/m. This flip-chip assembly process enables a new class of integrated electro-mechanical manufacturing at a low processing temperature massively and in parallel.
Global stabilization and convergence of nonlinear systems with uncertain exogenous dynamics

In this note, a class of nonlinear uncertain systems are considered, and uncertainties in the systems are assumed to be generated by exogenous dynamics. Robust control is designed by employing nonlinear observers to estimate the uncertainties. It is shown that, if a partial knowledge of the exogenous system is available and its known dynamics meet certain conditions or if input channel of the plant has certain properties, global stability and global estimation convergence can be achieved. In the latter case, the results on stability and convergence hold even if exogenous dynamics are completely unknown but bounded by some known function.
Quantum foam, gravitational thermodynamics, and the dark sector

Is it possible that the dark sector (dark energy in the form of an effective dynamical cosmological constant, and dark matter) has its origin in quantum gravity? This talk sketches a positive response. Here specifically quantum gravity refers to the combined effect of quantum foam (or spacetime foam due to quantum fluctuations of spacetime) and gravitational thermodynamics. We use two simple independent gedankan experiments to show that the holographic principle can be understood intuitively as having its origin in the quantum fluctuations of spacetime. Applied to cosmology, this consideration leads to a dynamical cosmological constant of the observed magnitude, a result that can also be obtained for the present and recent cosmic eras by using unimodular gravity and causal set theory. Next we generalize the concept of gravitational thermodynamics to a spacetime with positive cosmological constant (like ours) to reveal the natural emergence, in galactic dynamics, of a critical acceleration parameter related to the cosmological constant. We are then led to construct a phenomenological model of dark matter which we call "modified dark matter" (MDM) in which the dark matter density profile depends on both the cosmological constant and ordinary matter. We provide observational tests of MDM by fitting the rotation curves to a sample of 30 local spiral galaxies with a single free parameter and by showing that the dynamical and observed masses agree in a sample of 93 galactic clusters. We also give a brief discussion of the possibility that quanta of both dark energy and dark matter are non-local, obeying quantum Boltzmann statistics (also called infinite statistics) as described by a curious average of the bosonic and fermionic algebras. If such a scenario is correct, we can expect some novel particle phenomenology involving dark matter interactions. This may explain why so far no dark matter detection experiments have been able to claim convincingly to have detected dark matter.
Superconductivity and charge-density waves

Publisher Summary Superconductivity (SC) and charge-density wave (CDW) are the two most well-known cases of broken symmetry in a solid, which require an effective attractive electron–electron interaction. That interaction is normally provided by a phonon-mediated mechanism. It is therefore to be expected that systems in which CDWs have been experimentally observed also exhibit SC at very low temperatures. The tendencies toward the formation of SC and CDW are to a certain degree opposing one another. While the SC state has infinite conductivity and a Meissner effect, the CDW state, for large enough interactions, produces a semiconductor gap in the spectrum and a nonconducting state. From a microscopic point of view, on the other hand, the SC state arises from electron–electron coupling into Cooper pairs and the CDW state arises from electron-hole coupling and charge redistribution. These two effects are in principle independent of one another. This chapter discusses the interdependence of the SC and CDW states.
Intermediated surge pricing

Intermediated Surge Pricing Sushil Bikhchandani † December 2016 Abstract I study a market in which a profit-maximizing intermediary facilitates trade between buyers and sellers. The intermediary sets prices for buyers and sellers, and keeps the difference as her fee. Optimal prices increase with demand and, under plausible conditions, the optimal percent fee decreases with demand. However, if the intermediary keeps a constant percent fee regardless of demand, as is the case for some intermediaries, the price paid by buyers during high (low) demand increases (decreases) even further; that is, surge pricing is amplified. I am grateful to Keith Chen, Mamero Kaneko, Vijay Krishna, Barry Nalebuff, Joe Ostroy, and Asher Wolinsky for helpful comments. UCLA Anderson School of Management (sbikhcha@anderson.ucla.edu)
Anomalous amplification of a homodyne signal via almost-balanced weak values.

We propose precision measurements of ultra-small angular velocities of a mirror within a modified Sagnac interferometer, where the counter-propagating beams are spatially separated, using the recently proposed technique of almost-balanced weak values amplification (ABWV) [Phys. Rev. Lett.116, 100803 (2016)PRLTAO0031-900710.1103/PhysRevLett.116.100803]. The separation between the two beams provides additional amplification with respect to using collinear beams in a Sagnac interferometer. Within the same setup, the weak-value amplification technique is also performed for comparison. Much higher amplification factors can be obtained using the almost-balanced weak values technique, with the best one achieved in our experiments being as high as 1.2×107. In addition, the amplification factor monotonically increases with decreasing of the post-selection phase for the ABWV case in our experiments, which is not the case for weak-value amplification (WVA) at small post-selection phases. Both techniques consist of measuring the angular velocity. The sensitivity of the ABWV technique is ∼38 nrad/s per averaged pulse for a repetition rate of 1 Hz and ∼33 nrad/s per averaged pulse for the WVA technique.
Power control and relay selection in Full-Duplex Cognitive Relay Networks: Coherent versus non-coherent scenarios

This paper investigates power control and relay selection in Full Duplex Cognitive Relay Networks (FDCRNs), where the secondary-user (SU) relays can simultaneously receive and forward the signal from the SU source. We study both non-coherent and coherent scenarios. In the non-coherent case, the SU relay forwards the signal from the SU source without regulating the phase; while in the coherent scenario, the SU relay regulates the phase when forwarding the signal to minimize the interference at the primary-user (PU) receiver. We consider the problem of maximizing the transmission rate from the SU source to the SU destination subject to the interference constraint at the PU receiver and power constraints at both the SU source and SU relay. We develop low-complexity and high-performance joint power control and relay selection algorithms. The superior performance of the proposed algorithms are confirmed using extensive numerical evaluation. In particular, we demonstrate the significant gain of phase regulation at the SU relay (i.e., the gain of the coherent mechanism over the noncoherent mechanism).
The 3-state Potts model and Rogers-Ramanujan series

We explain the appearance of Rogers-Ramanujan series inside the tensor product of two basic A2(2) -modules, previously discovered by the first author in [Feingold A.J., Some applications of vertex operators to Kac-Moody algebras, In: Vertex Operators in Mathematics and Physics, Berkeley, November 10–17, 1983, Math. Sci. Res. Inst. Publ., 3, Springer, New York, 1985, 185–206]. The key new ingredients are (5,6)Virasoro minimal models and twisted modules for the Zamolodchikov W3-algebra.
Singlet fission in chiral carbon nanotubes: Density functional theory based computation

Singlet fission (SF) process, where a singlet exciton decays into a pair of spin one exciton states which are in the total spin singlet state, is one of the possible channels for multiple exciton generation (MEG). In chiral single-wall carbon nanotubes (SWCNTs), efficient SF is present within the solar spectrum energy range which is shown by the many-body perturbation theory calculations based on the density functional theory simulations. We calculate SF exciton-to-biexciton decay rates R1→2 and biexciton-to-exciton rates R2→1 in the (6,2), (6,5), (10,5) SWCNTs, and in the (6,2) SWCNT functionalized with Cl atoms. Within the solar energy range, we predict R1→2∼1014-1015 s-1, while biexciton-to-exciton recombination is weak with R2→1∕R1→2≤10-2. SF MEG strength in pristine SWCNTs varies strongly with the excitation energy, which is due to highly non-uniform density of states at low energy. However, our results for the (6,2) SWCNT with chlorine atoms adsorbed to the surface suggest that MEG in the chiral SWCNTs can be enhanced by altering the low-energy electronic states via surface functionalization.
A Search for Lost Planets in the Kepler Multi-planet Systems and the Discovery of the Long-period, Neptune-sized Exoplanet Kepler-150 f

The vast majority of the 4700 confirmed planets and planet candidates discovered by the Kepler space telescope were first found by the Kepler pipeline. In the pipeline, after a transit signal is found, all data points associated with those transits are removed, creating a Swiss cheese-like light curve full of holes, which is then used for subsequent transit searches. These holes could render an additional planet undetectable (or lost). We examine a sample of 114 stars with 3+ confirmed planets to see the effect that this Swiss cheesing may have. A simulation determined that the probability that a transiting planet is lost due to the transit masking is low, but non-neglible, reaching a plateau at approximately 3.3% lost in the period range of P = 400 - 500 days. We then model the transits in all quarters of each star and subtract out the transit signals, restoring the in-transit data points, and use the Kepler pipeline to search the transit-subtracted (i.e., transit-cleaned) light curves. However, the pipeline did not discover any credible new transit signals. This demonstrates the validity and robustness of the Kepler pipelines choice to use transit masking over transit subtraction. However, a follow-up visual search through all the transit-subtracted data, which allows for easier visual identification of new transits, revealed the existence of a new, Neptune-sized exoplanet. Kepler-150 f (P = 637.2 days, RP = 3.86 R earth) is confirmed using a combination of false positive probability analysis, transit duration analysis, and the planet multiplicity argument.
Painless Breakups -- Efficient Demixing of Low Rank Matrices

Assume we are given a sum of linear measurements of s different rank-r matrices of the form $$\varvec{y}= \sum _{k=1}^{s} \mathcal {A}_k (\varvec{X}_k)$$ . When and under which conditions is it possible to extract (demix) the individual matrices $$\varvec{X}_k$$ from the single measurement vector $$\varvec{y}$$ ? And can we do the demixing numerically efficiently? We present two computationally efficient algorithms based on hard thresholding to solve this low rank demixing problem. We introduce an Amalgam-Restricted Isometry Property which is especially suitable for demixing problems and prove that under appropriate conditions these algorithms are guaranteed to converge to the correct solution at a linear rate. We discuss applications in connection with quantum tomography and the Internet-of-Things. Numerical simulations demonstrate the empirical performance of the proposed algorithms.
On the pervasiveness of difference-convexity in optimization and statistics

With the increasing interest in applying the methodology of difference-of-convex (dc) optimization to diverse problems in engineering and statistics, this paper establishes the dc property of many functions in various areas of applications not previously known to be of this class. Motivated by a quadratic programming based recourse function in two-stage stochastic programming, we show that the (optimal) value function of a copositive (thus not necessarily convex) quadratic program is dc on the domain of finiteness of the program when the matrix in the objective function’s quadratic term and the constraint matrix are fixed. The proof of this result is based on a dc decomposition of a piecewise $$\hbox {LC}^1$$ function (i.e., functions with Lipschitz gradients). Armed with these new results and known properties of dc functions existed in the literature, we show that many composite statistical functions in risk analysis, including the value-at-risk (VaR), conditional value-at-risk (CVaR), optimized certainty equivalent, and the expectation-based, VaR-based, and CVaR-based random deviation functionals are all dc. Adding the known class of dc surrogate sparsity functions that are employed as approximations of the $$\ell _0$$ function in statistical learning, our work significantly expands the classes of dc functions and positions them for fruitful applications.
What Can We Learn from Predictive Modeling

The large majority of inferences drawn in empirical political research follow from model-based associations (e.g., regression). Here, we articulate the benefits of predictive modeling as a complement to this approach. Predictive models aim to specify a probabilistic model that provides a good fit to testing data that were not used to estimate the model’s parameters. Our goals are threefold. First, we review the central benefits of this under-utilized approach from a perspective uncommon in the existing literature: we focus on how predictive modeling can be used to complement and augment standard associational analyses. Second, we advance the state of the literature by laying out a simple set of benchmark predictive criteria. Third, we illustrate our approach through a detailed application to the prediction of interstate conflict.
Winnowing sequences from a database search.

In database searches for sequence similarity, matches to a distinct sequence region (e.g., protein domain) are frequently obscured by numerous matches to another region of the same sequence. In order to cope with this problem, algorithms are developed to discard redundant matches. One model for this problem begins with a list of intervals, each with an associated score; each interval gives the range of positions in the query sequence that align to a database sequence, and the score is that of the alignment. If interval I is contained in interval J, and I's score is less than J's, then I is said to be dominated by J. The problem is then to identify each interval that is dominated by at least K other intervals, where K is a given level of "tolerable redundancy." An algorithm is developed to solve the problem in O(N log N) time and O(N*) space, where N is the number of intervals and N* is a precisely defined value that never exceeds N and is frequently much smaller. This criterion for discarding database hits has been implemented in the Blast program, as illustrated herein with examples. Several variations and extensions of this approach are also described.
The Stochastic Matching Problem: Beating Half with a Non-Adaptive Algorithm

In the stochastic matching problem, we are given a general (not necessarily bipartite) graph G(V,E), where each edge in E is realized with some constant probability p > 0 and the goal is to compute a bounded-degree (bounded by a function depending only on p) subgraph H of G such that the expected maximum matching size in H is close to the expected maximum matching size in G. The algorithms in this setting are considered non-adaptive as they have to choose the subgraph H without knowing any information about the set of realized edges in G. Originally motivated by an application to kidney exchange, the stochastic matching problem and its variants have received significant attention in recent years. The state-of-the-art non-adaptive algorithms for stochastic matching achieve an approximation ratio of 1/2-e for any e > 0, naturally raising the question that if 1/2 is the limit of what can be achieved with a non-adaptive algorithm. In this work, we resolve this question by presenting the first algorithm for stochastic matching with an approximation guarantee that is strictly better than 1/2: the algorithm computes a subgraph H of G with the maximum degree O(log(1/p)/p such that the ratio of expected size of a maximum matching in realizations of H and G is at least 1/2 + δ0 for some absolute constant δ0 > 0. The degree bound on H achieved by our algorithm is essentially the best possible (up to an O(log(1/p)) factor) for any constant factor approximation algorithm, since an Ω(1/p) degree in H is necessary for a vertex to acquire at least one incident edge in a realization. Our result makes progress towards answering an open problem of Blum et al (EC 2015) regarding the possibility of achieving a (1 - e)-approximation for the stochastic matching problem using non-adaptive algorithms. From the technical point of view, a key ingredient of our algorithm is a structural result showing that a graph whose expected maximum matching size is OPT always contains a b-matching of size (essentially) b ... OPT, for b = 1/p.
Towards a compact fiber laser for multimodal imaging

We report on multimodal depth-resolved imaging of unstained living Drosophila Melanogaster larva using sub-50 fs pulses centered at 1060 nm wavelength. Both second harmonic and third harmonic generation imaging modalities are demonstrated.