cssi/SciSciGPT-SciSciNet huggingface dataset:
Specialization, Productivity, and Financing Constraints

We analyze optimal financial contracts when the specificity of investments is endogenous. Specialization decreases the liquidation value of assets, but improves the asset's long-term productivity. While the former is known to make financing more difficult, we show that the latter can ease financing constraints and increase financing capacity by improving an entrepreneur's incentive to repay. The overall impact of specialization on the terms of financing depends on which effect is more important. Specialization decisions interact with the nature of investments, their timing, the need for outside financing, and an entrepreneur's ability to commit to a level of specialization. The Author 2013. Published by Oxford University Press on behalf of The Society for Financial Studies. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com., Oxford University Press.
Coarse‐grained description of thermo‐capillary flow

A mesoscopic or coarse‐grained approach is presented to study thermo‐capillary induced flows. An order parameter representation of a two‐phase binary fluid is used in which the interfacial region separating the phases naturally occupies a transition zone of small width. The order parameter satisfies the Cahn–Hilliard equation with advective transport. A modified Navier–Stokes equation that incorporates an explicit coupling to the order parameter field governs fluid flow. It reduces, in the limit of an infinitely thin interface, to the Navier–Stokes equation within the bulk phases and to two interfacial forces: a normal capillary force proportional to the surface tension and the mean curvature of the surface, and a tangential force proportional to the tangential derivative of the surface tension. The method is illustrated in two cases: thermo‐capillary migration of drops and phase separation via spinodal decomposition, both in an externally imposed temperature gradient.
Annual hydroclimatology of the United States

[1] An overview of the annual hydroclimatology of the United States is provided. Time series of monthly streamflow, temperature, and precipitation are developed for 1337 watersheds in the United States. This unique data set is then used to evaluate several approaches for estimating the long-term water balance and the interannual variability of streamflow. Traditional relationships which predict either actual evapotranspiration or the interannual variability of streamflow from an aridity index are shown to perform poorly for basins with low soil moisture storage capacity. A water balance model is used to formulate new relationships for predicting actual evapotranspiration and the interannual variability of streamflow. These relationships depend on both the aridity index and a new soil moisture storage index. A physically based approach for estimating the soil moisture storage index is introduced which requires monthly time series of precipitation, potential evapotranspiration, and an estimate of maximum soil moisture holding capacity. The net results are improved expressions for the long-term water balance and the interannual variability of streamflow which do not require either calibration or streamflow data.
Developing metal-mediated and catalyzed reactions in air and water

Chao-Jun Li gives a personal perspective on research that won the 2001 Presidential Green Chemistry Challenge Award (academic category)
Attack monitoring and localization in All-Optical Networks

An attacker's connection can propagate quickly to different parts of a transparent All-Optical Network. Such attacks affect the normal traffic and cause a quality of service degradation or outright service denial. Attack monitors can collect the information of each link and each node to help diagnose the attacker's exact location. Quick detection and localization of an attack source helps avoid losing large amounts of data in an all-optical network. However, to detect attack sources, it is not necessary to put monitors on all nodes. Since not every wavelength on every link is being used all the time, we propose to use the idle wavelengths to setup diagnostic connections and obtain the necessary information needed for diagnosis purposes. We show that placing a relatively small number of monitors at some key nodes in a network is sufficient to achieve level of performance. However, the monitor placement policy, routing policy, and diagnosis method are challenging problems. We, in this paper, first develop a monitor placement policy, a test connection policy, and a routing policy based on our definition of crosstalk attack and monitor node models. With these policies, we show that we can always detect and localize the malicious connections as long as there is no more than one malicious connection on each wavelength in the whole network. After this, we develop a scalable diagnosis method, which can localize the sources of the such malicious attacks in a fast manner.
Convergence of goal‐oriented adaptive finite element methods for nonsymmetric problems

In this article we develop convergence theory for a class of goal-oriented adaptive finite element algorithms for second order nonsymmetric linear elliptic equa- tions. In particular, we establish contraction and quasi-optimality results for a method of this type for second order Dirichlet problems involving the elliptic operatorLu = r (Aru) br u cu; with A Lipschitz, almost-everywhere symmetric positive def- inite (SPD), with b divergence-free, and with c 0. We first describe the problem class and review some standard facts concerning conforming finite element discretization and error-estimate-driven adaptive finite element methods (AFEM). We then describe a goal- oriented variation of standard AFEM (GOAFEM). Following the recent work of Mom- mer and Stevenson for symmetric problems, we establish contraction of GOAFEM. We also then show convergence in the sense of the goal function. Our analysis approach is signficantly different from that of Mommer and Stevenson, combining the recent con- traction frameworks developed by Cascon et. al, by Nochetto, Siebert, and Veeser, and by Holst, Tsogtgerel, and Zhu. In the last part of the paper we perform a complexity analysis, and establish quasi-optimal cardinality of GOAFEM. The somewhat long ap- pendix contains a number of supporting estimates and other results that are often used for AFEM convergence analysis, yet the proofs of these results themselves are somewhat difficult to find in the literature. CONTENTS
Leaving or Staying: Inter-Provincial Migration in Vietnam

Internal migration has several policy implications for economic growth and development for developing countries in general and for the fast growing low-income country of Vietnam in particular. Little research has been done, however, on inter-provincial migration in Vietnam. This study makes two major contributions to the migration and development literature in terms of the datasets and policy-relevant estimation approach. It is the first paper to use the annual survey data on migration published by Vietnam’s General Statistics Office. This study also adopts a functional form to accommodate the flexibility of income’s elasticity. Income, together with urban unemployment rates, are endogenously estimated with instruments that prove to be strong and valid. The inclusion of policy-relevant variables provides empirical findings that can make migration policy in Vietnam better-informed. Specifically, Vietnamese migrants are influenced primarily by moving costs, expected income differentials, disparity in the quality of public services offered by provinces, and the demographic composition at destination and source. This paper’s findings provide new insight for migration policy options, and suggest that the government adopt a holistic policy approach to maximize the benefits and minimize the costs associated with internal migration.
The Eyes of the Needles: A Sequential Model of Union Organizing Drives, 1999–2004

�This paper models three stages of the union organizing drive, using a new dataset covering more than 22,000 drives that took place between 1999 and 2004. The correlated sequential model tracks drives through all of their potential stages: holding an election, winning an election, and reaching first contracts. Only one-seventh of organizing drives that filed an election petition with the NLRB managed to reach a first contract within a year of certification. The model, which controls for the endogeneity of unfair labor practice (ULP) charges, finds that a ULP charge was associated with a �0% smaller cumulative chance of reaching such a contract. ULP charges had less effect on the votes cast than on the decision to hold an election and the ability to reach a first contract. A sequential model such as this one could be extended to test between some competing theories about the determinants of union organizing.
Quantum complex Hénon–Heiles potentials

Abstract Quantum-mechanical PT -symmetric theories associated with complex cubic potentials such as V=x2+y2+igxy2 and V=x2+y2+z2+igxyz, where g is a real parameter, are investigated. These theories appear to possess real, positive spectra. Low-lying energy levels are calculated to very high order in perturbation theory. The large-order behavior of the perturbation coefficients is determined using multidimensional WKB tunneling techniques. This approach is also applied to the complex Henon–Heiles potential V=x2+y2+ig(xy2−(1/3)x3).
Complete accessibility of oscillations in robotic systems by orthogonal projections

The current practice of controller development for flexible robotic systems generally focuses on one-link robotic arms and is valid for small oscillations. This work addresses the control of n-link, serial, spatial robotic systems modeled with m1 joint and m2 link flexibilities such that n≥m1 +m2 . System compliance is modeled by local springs and nonactuated prismatic and revolute type pseudo joints. The coupled, nonlinear, error-driven system equations are derived for the complete model without linearization or neglecting certain terms. For this system, the complete accessibility of vibrations is studied by orthogonal projections. It is shown that under some configurations of a robotic system, the induced oscillations may not be accessible to the controller. Given accessibility, the controller developed in this work assures the global asymptotic stability of the system. Example numerical simulations are presented based on the model of a six-degree-of-freedom Cincinnati Milacron T3-776 industrial robot. One example models the system compliance in four joints, while another case study simulates four lateral link oscillations. These examples show that this controller, even under inaccurate payload description, eliminates the oscillations while tracking desired trajectories.
Structure, activity, synthesis and biosynthesis of aryl-C-glycosides

Covering: the literature up to April 2005The focus of this review is to highlight the structure, bioactivity and biosynthesis of naturally occurring aryl-C-glycosides. General synthetic methods and their relevance to proposed biochemical mechanisms for the aryl-C-glycoside bond formation are also presented.
The Influence of Differential Irradiation and Circulation on the Thermal Evolution of Gas Giant Planets. I. Upper Limits from Radiative Equilibrium

As a planet ages, it cools and its radius shrinks at a rate set by the efficiency with which heat is transported from the interior out to space. The bottleneck for this transport is at the boundary between the convective interior and the radiative atmosphere; the opacity there sets the global cooling rate. Models of planetary evolution are often one dimensional (1D), such that the radiative-convective boundary (RCB) is defined by a single temperature, pressure, and opacity. In reality the spatially inhomogeneous stellar heating pattern and circulation in the atmosphere could deform the RCB, allowing heat from the interior to escape more efficiently through regions with lower opacity. We present an analysis of the degree to which the RCB could be deformed and the resultant change in the evolutionary cooling rate. In this initial work we calculate the upper limit for this effect by comparing an atmospheric structure in local radiative equilibrium to its 1D equivalent. We find that the cooling through an uneven RCB could be enhanced over cooling through a uniform RCB by as much as 10%-50%. We also show that the deformation of the RCB (and the enhancement of the cooling rate) increases with a greater incident stellar flux or a lower inner entropy. Our results indicate that this mechanism could significantly change a planet's thermal evolution, causing it to cool and shrink more quickly than would otherwise be expected. This may exacerbate the well-known difficulty in explaining the very large radii observed for some hot Jupiters.
Limitations of Phased Array Beamforming in Open Rotor Noise Source Imaging

Phased array beamforming results of the F31/A31 historical baseline counter-rotating open rotor blade set were investigated for measurement data taken on the General Electric Counter-Rotating Open Rotor Propulsion Rig in the 9’ x 15’ Low Speed Wind Tunnel of NASA Glenn Research Center as well as data produced using the LINPROP open rotor tone noise code. The planar microphone array was positioned broadside and parallel to the axis of the open rotor, roughly 2.3 rotor diameters away. The results provide insight as to why the apparent noise sources of the blade passing frequency tones and interaction tones appear at their nominal Mach radii instead of at the actual noise sources, even if those locations are not on the blades. Contour maps corresponding to the sound fields produced by the radiating sound waves, taken from the simulations, are used to illustrate how the interaction patterns of circumferential spinning modes of rotating coherent noise sources interact with the phased array, often giving misleading results, as the apparent sources do not always show where the actual noise sources are located. This suggests that a more sophisticated source model would be required to accurately locate the sources of each tone. The results of this study also have implications with regard to the shielding of open rotor sources by airframe empennages.
A spectral technique for random satisfiable 3CNF formulas

Let I be a random 3CNF formula generated by choosing a truth assignment p for variables x1, xn uniformly at random and including every clause with i literals set true by p with probability pi, independently. We show that for any constants 0 ≤ η2,η3 ≤ 1 there is a constant dmin so that for all d ≥ dmin a spectral algorithm similar to the graph coloring algorithm of Alon and Kahale will find a satisfying assignment with high probability for p1 = d-n2, p2 = η2d-n2, and p3 = η3d-n2. Appropriately setting the ηi's yields natural distributions on satisfiable 3CNFs, not-all-equal-sat 3CNFs, and exactly-one-sat 3CNFs. © 2008 Wiley Periodicals, Inc. Random Struct. Alg., 2008
The Error of Expected Loss Minimization

Considerable effort has been expended by legal scholars attempting to apply formal approaches such as Bayes’ Theorem or decision theory to various aspects of the litigation process. These efforts consistently fail adequately to account for the reality of the phenomenon being investigated. Most recently, Professor Kaye attempted to give another decision-theoretic account of the standard of persuasion in civil cases. This attempt fails formally, as it requires that litigation involve single issues for decision, which is virtually never the case. It fails pragmatically because it ignores all the surrounding context of the decision rule that colours and gives meaning to the decision rule. Jury trials cannot plausibly be analysed as designed to maximize the expected return to jurors.
Planets in Open Clusters Detectable by Kepler

While hundreds of planets have been discovered around field stars, only a few are known in star clusters. To explain the lack of short-period giant planets in globular clusters (GCs), such as 47 Tucane and ω Centauri, it has been suggested that their low metallicities may have prevented planet formation. Alternatively, the high rates of close stellar encounters in these clusters may have influenced the formation and subsequent evolution of planetary systems. How common are planets in clusters around normal main-sequence stars? Here we consider whether this question can be addressed using data from the Kepler mission. The Kepler field of view contains four low-density (relative to GCs) open clusters where the metallicities are about solar (or even higher) and stellar encounters are much less frequent than in typical GCs. We provide detailed N-body models and show that most planets in Kepler-detectable orbits are not significantly perturbed by stellar encounters in these open clusters. We focus on the most massive cluster, NGC 6791, which has supersolar metallicity, and find that if planets formed in this cluster at the same frequency as observed in the field, Kepler could detect 1–20 transiting planets depending on the planet-size distribution and the duration of data collection. Due to the large distance to NGC 6791 Kepler will have to search relatively faint (Kp < 20) stars for the full extended mission to achieve such a yield.
Futures Market Failure

In a well‐functioning futures market, the futures price at expiration equals the price of the underlying asset. This condition failed to hold in grain markets for most of 2005‐2010, calling into question the ability of these markets to perform their price discovery and risk management functions. During this period, futures contracts expired up to 35% above the cash grain price. We develop a dynamic rational expectations model of commodity storage that explains how these recent convergence failures were generated by the institutional structure of the delivery system. When delivery occurs on a grain futures contract, the firm on the short side of the market provides a delivery instrument (a warehouse receipt or shipping certificate) to the firm on the long side of the market. The firm taking delivery may hold the delivery instrument indefinitely, providing it pays a daily storage rate. The futures exchange sets the maximum allowable storage rate at a fixed value. We show that non‐convergence arises in equilibrium when the market price of physical grain storage exceeds the maximum storage rate on delivery instruments. We call the difference between the price of carrying physical grain and the maximum storage rate the wedge, and demonstrate theoretically and empirically that the magnitude of the non‐convergence equals the expected present discounted value of a function of future wedges.
What to Expect from Transiting Multiplanet Systems

So far radial velocity measurements have discovered ~25 stars to host multiple planets. The statistics imply that many of the known hosts of transiting planets should have additional planets, yet none have been solidly detected. They will be soon, via complementary search methods of RV, transit-time variations of the known planet, and transits of the additional planet. When they are found, what can transit measurements add to studies of multiplanet dynamical evolution? First, mutual inclinations become measurable, for comparison to the solar system's disk-like configuration. Such measurements will give important constraints to planet-planet scattering models, just as the radial velocity measurements of eccentricity have done. Second, the Rossiter-McLaughlin effect measures stellar obliquity, which can be modified by two-planet dynamics with a tidally evolving inner planet. Third, transit-time variations are exquisitely sensitive to planets in mean motion resonance. Two planets differentially migrating in the disk can establish such resonances, and tidal evolution of the planets can break them, so the configuration and frequency of these resonances as a function of planetary parameters will constrain these processes.
Electromagnetic Properties of Diquarks

Diquark correlations play an important role in hadron physics. The properties of diquarks can be obtained from the corresponding bound-state equation. Using a model for the effective quark-quark interaction that has been proved successfully in the light meson sector, we solve the scalar diquark Bethe-Salpeter equations and use the obtained Bethe-Salpeter amplitudes to compute the diquarks’ electromagnetic form factors. The scalar ud diquark charge radius is about 8% larger than the pion charge radius, indicating that these diquarks are somewhat larger in size than the corresponding mesons. We also provide analytic fits for the form factor over a moderate range in Q2, which may be useful, for example, in building quark-diquark models of nucleons.
El tiempo en las filosofías románticas de la música

Time in romantic philosophies of music.- Romanticism, as an intellectual movement, presupposes a new vision, one which we are still living off. This paper makes a critique of time in the music of the period, and in musical thought of the period (taking for granted that the music and the thought are eseentially related). In this context, the question is raised, what conception of time is to be found in the philosophers of the nineteenth and twentieth centuries? This leads on to a study of time in music and in musical theory, especially in those of the nineteenth centuries.
Synthesis and thiolation of 1,3-difluoro-2,4,6-trihaloanilines and benzenes

Abstract Three pentahaloanilines were prepared by stepwise halogenation of 3,5-difluoroaniline and were deaminated to form pentahalobenzenes. Alternatively, two pentahalobenzenes were obtained by lithiation followed by iodination of 1,3-difluoro-4,6-dihalobenzenes. Alkylthiolation reactions of pentahaloanilines and benzenes in Me2SO were investigated.
CONTEMPORARY POLYMERS: ALL OUR BURDENS NOW OVER?

Moderately to highly crosslinked UHMWPEs have functioned for at least a decade with dramatic reduction in wear volumes in THA. This wear reduction has been associated with a markedly reduced incidence of radiographic osteolysis. However, CT studies have demonstrated that osteolysis is not completely eliminated. There, however, are still questions which include: Is cost for further improvements warranted?; Is 10 years long enough to assure that no clinically relevant osteolysis occurs, especially in younger patients?; Do we have any data demonstrating improvement in revision scenarios?; With high levels of crosslinking (requiring more radiation) some fractures have been demonstrated at the region of the locking mechanism of the liner to shell. Will this prevalence increase? These materials are softer and can cause quicker crack propagation than conventional polyethylene.; Do better locking mechanisms need to be developed to prevent fracture problems that have been demonstrated in the present generation cementless designs?; Do we need more information as to the optimal counterface choice (cobalt chrome, ceramic, oxinium)?; Can hip results be extrapolated to the knee where fatigue failure is a major problem both on the bearing surface and with the locking mechanism?; Is the oxidation we are beginning to see on the surface of retrieved liners (thought to be related to lipids from the synovium and cyclical loading) the tip of the iceberg? I too am encouraged by the mid-term results of crosslinked polyethylene. Our own data supports it. However, we must keep in mind the questions outlined.
Strategic Pricing in Next-Hop Routing with Elastic Demands

We consider a model of next-hop routing by self-interested agents. In this model, nodes in a graph (representing ISPs, Autonomous Systems, etc.) make pricing decisions of how much to charge for forwarding traffic from each of their upstream neighbors, and routing decisions of which downstream neighbors to forward traffic to (i.e., choosing the next hop). Traffic originates at a subset of these nodes that derive a utility when the traffic is routed to its destination node; the traffic demand is elastic and the utility derived from it can be different for different source nodes. Our next-hop routing and pricing model is in sharp contrast with the more common source routing and pricing models, in which the source of traffic determines the entire route from source to destination. For our model, we begin by showing sufficient conditions for prices to result in a Nash equilibrium, and in fact give an efficient algorithm to compute a Nash equilibrium which is as good as the centralized optimum, thus proving that the price of stability is 1. When only a single source node exists, then the price of anarchy is 1 as well, as long as some minor assumptions on player behavior is made. The above results hold for arbitrary convex pricing functions, but with the assumption that the utilities derived from getting traffic to its destination are linear. When utilities can be non-linear functions, we show that Nash equilibrium may not exist, even with simple discrete pricing models.
Design for diagnosis using a diagnostic evaluation measure

The results demonstrated by the SAN system show how a real fault tolerant system can have more than one configuration with almost the same reliability. However, from a diagnosis perspective, the designs can have different costs of diagnosis at failure time. A method for measuring the cost of diagnosing diagnosis decision trees (DDT) was demonstrated, which is a specialized weighted mean depth of traversing the DDT. This evaluation method incorporates the qualitative (structure) and quantitative (reliability analysis) into one measure for predicting diagnosis cost. DDTs incorporate the same qualitative and quantitative data as the diagnosis cost measure, which makes this measure suitable for evaluating these decision trees. Evaluating and comparing alternative system designs using the diagnosis cost function as we demonstrated is an efficient and simple method for pursuing the design for diagnosis objective
Subtypes of muscarinic receptors regulating gallbladder cholinergic contractions.

The aim of this study was to determine the functional role of muscarinic receptor subtypes regulating gallbladder cholinergic contractions. Electrical field stimulation (EFS; 16 Hz) produced contra...
IS Imbalances and Current Account Surpluses in Japan: In Memory of Professor Ronald I. McKinnon

In this paper, I find (1) that Japan showed massive and persistent current account surpluses from at least 1981 until at least 2011, (2) that Professor Ronald McKinnon was correct, at least in the case of Japan, and that these large and persistent current account surpluses were due primarily to Japan’s large and persistent IS imbalances (the excess of saving over investment), (3) that the specific causes of the IS imbalances have changed dramatically over time, and (4) that future trends in Japan’s IS imbalances (current account surpluses) are difficult to project but that they will probably not change dramatically in either direction in the foreseeable future.
Remark on the formula by Rakhmanov and Steklov's conjecture

The conjecture by Steklov was solved negatively by Rakhmanov in 1979. His original proof was based on the formula for orthogonal polynomial obtained by adding point masses to the measure of orthogonality. In this note, we show how this polynomial can be obtained by applying the method developed recently for proving the sharp lower bounds for the problem by Steklov.
Positivity and Fourier integrals over regular hexagon

Let f ? L 1 ( R 2 ) and let f ? be its Fourier integral. We study summability of the partial integral S ? , H ( x ) = ? { ? y ? H ? ? } e i x ? y f ? ( y ) d y , where ? y ? H denotes the uniform norm taken over the regular hexagonal domain. We prove that the Riesz ( R , ? ) means of the inverse Fourier integrals are nonnegative if and only if ? ? 2 . Moreover, we describe a class of ? ? ? H -radial functions that are positive definite on R 2 .
Facile One‐Pot Synthesis of 2‐Aryl‐substituted Nitriles and 2‐Aryl‐3‐keto Nitriles via Benzyne Reaction

Abstract 2‐Aryl‐substituted nitriles were prepared in good to excellent yields in a one‐pot reaction by the reaction of benzyne, generated using neutral conditions from (phenyl)[o‐(trimethylsilyl)‐phenyl]iodonium triflate, and 2‐lithionitriles. 3‐Keto nitriles substituted at the 2‐position were obtained in good yields when these reactions were trapped with acid chlorides. The mechanism of the benzyne reaction in terms of a N‐lithiobenzocyclobutanimine intermediate is discussed.
A Statistical Comparison Between Severe Accidents And PDO Accidents In Riyadh

Riyadh, capital of the Kingdom of Saudi Arabia, is a fast developing and modernized city. With a population of three million inhabitants and a motorized rate (population per vehicle) of 3.8, Riyadh has been experiencing increasing traffic accident problems. Official statistics have shown that more than 400 fatalities and 3000 injuries occur annually due to traffic accidents. The severity index of traffic accidents over the past four years is higher than the corresponding nationwide index. This study aims at investigating the severity of traffic accidents in Riyadh. An attempt was made to compare property damage only (PDO) accidents with severe accidents in order to analyze the nature of severe accidents and determine their characteristics so that some remedies can be recommended. For achieving this purpose, a total of 1774 police-reported accidents was collected in a systematic random manner for the period of 1996 through 1997. Analysis using various test statistics was conducted to compare the two categories of accidents. The study found that improper driving behavior is the primary cause of accidents in Riyadh and the young drivers are most often the victims in such accidents. In addition, the taxis and pick-up trucks are in high risk of being involved in accidents. The analysis indicates that there is an urgent need for reviewing existing public awareness programs and law enforcement strategies.
Detecting superlight dark matter with Fermi-degenerate materials

We examine in greater detail the recent proposal of using superconductors for detecting dark matter as light as the warm dark matter limit of $$ \mathcal{O} $$ (keV). Detection of suc light dark matter is possible if the entire kinetic energy of the dark matter is extracted in the scattering, and if the experiment is sensitive to $$ \mathcal{O} $$ (meV) energy depositions. This is the case for Fermi-degenerate materials in which the Fermi velocity exceeds the dark matter velocity dispersion in the Milky Way of ∼ 10−3. We focus on a concrete experimental proposal using a superconducting target with a transition edge sensor in order to detect the small energy deposits from the dark matter scatterings. Considering a wide variety of constraints, from dark matter self-interactions to the cosmic microwave background, we show that models consistent with cosmological/astrophysical and terrestrial constraints are observable with such detectors. A wider range of viable models with dark matter mass below an MeV is available if dark matter or mediator properties (such as couplings or masses) differ at BBN epoch or in stellar interiors from those in superconductors. We also show that metal targets pay a strong in-medium suppression for kinetically mixed mediators; this suppression is alleviated with insulating targets.
The Equivalence of the Torus and the Product of Two Circles in Homotopy Type Theory

Homotopy type theory is a new branch of mathematics that merges insights from abstract homotopy theory and higher category theory with those of logic and type theory. It allows us to represent a variety of mathematical objects as basic type-theoretic construction, higher inductive types. We present a proof that in homotopy type theory, the torus is equivalent to the product of two circles. This result indicates that the synthetic definition of torus as a higher inductive type is indeed correct.
The Kirchhoff-Braess paradox and its implications for smart microgrids

Well known in the theory of network flows, Braess paradox states that in a congested network, it may happen that adding a new path between destinations can increase the level of congestion. In transportation networks the phenomenon results from the decisions of network participants who selfishly seek to optimize their own performance metrics. In an electric power distribution network, an analogous increase in congestion can arise as a consequence Kirchhoff's laws. Even for the simplest linear network of resistors and voltage sources, the sudden appearance of congestion due to an additional conductive line is a nonlinear phenomenon that results in a discontinuous change in the network state. It is argued that the phenomenon can occur in almost any grid in which they are loops, and with the increasing penetration of small-scale distributed generation, it suggests challenges ahead in the operation of microgrids.
A semi-supervised method for predicting cancer survival using incomplete clinical data

Prediction of survival for cancer patients is an open area of research. However, many of these studies focus on datasets with a large number of patients. We present a novel method that is specifically designed to address the challenge of data scarcity, which is often the case for cancer datasets. Our method is able to use unlabeled data to improve classification by adopting a semi-supervised training approach to learn an ensemble classifier. The results of applying our method to three cancer datasets show the promise of semi-supervised learning for prediction of cancer survival.
D-branes and creation of strings

We review two types of D-branes processes where open strings are created. In the first type, a closed string incident on a collection of D-branes is converted into a number of open strings running along them. For the case of threebranes we compare the leading absorption rate with that in semiclassical gravity, and find exact agreement. A supersymmetric non-renormalization theorem guarantees that this agreement survives all corrections in powers of the string coupling times the number of branes. The second type of process is creation of stretched open strings by crossing D-branes. We show that this is possible whenever a p-brane passes through an (8-p)-brane positioned orthogonally to it. The extra attractive force exerted by the stretched open string is crucial for finding that the net force cancels in this BPS system.
Public Choice Theory and the Private Securities Market

One of the most important developments in the capital markets over the past decade presents a puzzle that needs to be solved. The development is the dramatic expansion of the unregulated market for private securities in the United States. The puzzle is that public choice theory, the dominant theory for explaining the behavior of the Securities and Exchange Commission (“SEC”), fails to account for it. After all, the traditional public choice account predicts that the SEC will grow its regulatory turf, not erode it. This Article develops a theory that solves this puzzle. The argument is that the traditional public choice account overlooks an important class of cases where regulators have incentives to expand the unregulated portion of their industry. With respect to the SEC, this Article argues that, by growing the private securities market, actors at the SEC maximize support for their current and future careers in the face of uncertainty over how to reinvigorate a dysfunctional public market.
Active Stabilization of a Diode Laser Injection Lock

We report on a device to electronically stabilize the optical injection lock of a semiconductor diode laser. Our technique uses as discriminator the peak height of the laser’s transmission signal on a scanning Fabry-Perot cavity and feeds back to the diode current, thereby maintaining maximum optical power in the injected mode. A two-component feedback algorithm provides constant optimization of the injection lock, keeping it robust to slow thermal drifts and allowing fast recovery from sudden failures such as temporary occlusion of the injection beam. We demonstrate the successful performance of our stabilization method in a diode laser setup at 399 nm used for laser cooling of Yb atoms. The device eases the requirements on passive stabilization and can benefit any diode laser injection lock application, particularly those where several such locks are employed.
Separation of routing and scheduling in backpressure: based wireless networks

Backpressure routing and scheduling, with its throughput-optimal operation guarantee, is a promising technique to improve throughput in wireless multihop networks. Although backpressure is conceptually viewed as layered, the decisions of routing and scheduling are made jointly, which imposes several challenges in practice. In this work, we present Diff-Max, an approach that separates routing and scheduling and has three strengths: 1) Diff-Max improves throughput significantly; 2) the separation of routing and scheduling makes practical implementation easier by minimizing cross-layer operations; i.e., routing is implemented in the network layer and scheduling is implemented in the link layer; and 3) the separation of routing and scheduling leads to modularity; i.e., routing and scheduling are independent modules in Diff-Max, and one can continue to operate even if the other does not. Our approach is grounded in a network utility maximization (NUM) formulation and its solution. Based on the structure of Diff-Max, we propose two practical schemes: Diff-subMax and wDiff-subMax. We demonstrate the benefits of our schemes through simulation in ns-2.
The scale of supersymmetry breaking as a free parameter

Abstract While supersymmetric extensions of the Standard Model can be fully described in terms of explicitly broken global supersymmetry, this description is only effective. Once related to spontaneous breaking in a more fundamental theory, the effective parameters translate to functions of two distinct scales, the scale of spontaneous supersymmetry breaking and the scale of its mediation to the standard-model fields. The scale dependence will be written explicitly and the full spectrum of supersymmetry breaking operators which emerges will be explored. It will be shown that, contrary to common lore, scale-dependent operators can play an important role in determining the phenomenology. For example, theories with low-energy supersymmetry breaking, such as gauge mediation, may correspond to a scalar potential which is quite different than in theories with high-energy supersymmetry breaking, such as gravity mediation. As a concrete example, the Higgs mass prediction will be discussed in some detail and its upper bound will be shown to be sensitive to the supersymmetry breaking scale.
Does Encouragement Matter in Improving Gender Imbalances in Technical Fields? Evidence from a Randomized Controlled Trial.

Does encouragement help address gender imbalances in technical fields? We present the results of one of the first and largest randomized controlled trials on the topic. Using an applied statistics conference in the social sciences as our context, we randomly assigned half of a pool of 3,945 graduate students to receive two personalized emails encouraging them to apply (n = 1,976) and the other half to receive nothing (n = 1,969). We find a robust, positive effect associated with this simple intervention and suggestive evidence that women responded more strongly than men. However, we find that women’s conference acceptance rates are higher within the control group than in the treated group. This is not the case for men. The reason appears to be that female applicants in the treated group solicited supporting letters at lower rates. Our findings therefore suggest that “low dose” interventions may promote diversity in STEM fields but may also have the potential to expose underlying disparities when used alone or in a non-targeted way.
Actions Arising from Intersection and Union

An action is a pair of sets, C and S, and a function $$f:C\times S \rightarrow C$$f:C×S?C. Rothschild and Yalcin gave a simple axiomatic characterization of those actions arising from set intersection, i.e. for which the elements of C and S can be identified with sets in such a way that elements of S act on elements of C by intersection. We introduce and axiomatically characterize two natural classes of actions which arise from set intersection and union. In the first class, the $$\uparrow \!\!\downarrow $$??-actions, each element of S is identified with a pair of sets $$(s^\downarrow ,s^\uparrow )$$(s?,s?), which act on a set c by intersection with $$s^\downarrow $$s? and union with $$s^\uparrow $$s?. In the second class, the $$\uparrow \!\!\downarrow $$??-biactions, each element of S is labeled as an intersection or a union, and acts accordingly on C. We give intuitive examples of these actions, one involving conversations and another a university's changing student body. The examples give some motivation for considering these actions, and also help give intuitive readings of the axioms. The class of $$\uparrow \!\!\downarrow $$??-actions is closely related to a class of single-sorted algebras, which was previously treated by Margolis et al., albeit in another guise (hyperplane arrangements), and we note this connection. Along the way, we make some useful, though very general, observations about axiomatization and representation problems for classes of algebras.
Sustainable Intensification and Farmer Preferences for Crop System Attributes: Evidence from Malawi's Central and Southern Regions

Summary Low soil fertility is a limiting factor to farm productivity, household nutrition, and economic development in many parts of Africa due to the continuous cultivation of maize over centuries. Diversifying maize monocrop with legumes has been proposed as one solution to declining soil fertility. Adoption of legumes in Africa remains low despite the much needed soil fertility and nutrition benefits provided by the crops. We employ choice experiments to examine farmers’ preferences for groundnut, soybean, and pigeon pea intercropped with maize and explore barriers and drivers to adoption in Central and Southern Malawi. Overall, farmers significantly discount legume yields in favor of maize yields despite the additional benefits provided by legumes. Labor constraints and market access are potentially more important barriers to legume adoption than previously thought. Results identified three types of farmers with varying preferences for grain yields, the largest group (48%) associated with strongly positive preference for both legume and maize grain yield, a medium-sized group (35%) that values only maize yield, and the smallest group (17%) having preferences only for legume yield. The medium group may be growing legumes for other benefits such as enhanced maize productivity, and the smallest group may be primarily subsistence producers. These findings suggest that uptake of legume maize intercrop systems might be improved if practitioners focus on legumes that have lower labor requirements and better marketability.
A Probabilistic Characterization of the Dominance Order on Partitions

We present a probabilistic characterization of the dominance order on partitions. Let ν be a partition and Y ν its Ferrers diagram, i.e. a stack of rows of cells with row i containing ν i cells. Let the cells of Y ν be filled with independent and identically distributed draws from the random variable X = B i n(r, p) with r ≥ 1 and p ∈ (0, 1). Given j, t ≥ 0, let P(ν, j, t) be the probability that the sum of all the entries in Y ν is j while the sum of the entries in each row of Y ν is no more than t. It is shown that if ν and μ are two partitions of n, ν dominates μ if and only if P(ν, j, t) ≤ P(μ, j, t) for all j, t ≥ 0. It is shown that the same result holds if X is any log-concave integer valued random variable with {i : P(X = i) > 0} = {0, 1,…,r} for some r ≥ 1.
Microginins 680, 646, and 612—new chlorinated Ahoa-containing peptides from a strain of cultured Microcystis aeruginosa

Abstract Chemical investigation of a cultured strain of Microcystis aeruginosa revealed the presence of three new microginin analogs, microginins 680, 646, and 612. While nearly all other previously reported microginins possess the unusual 3-amino-2-hydroxydecanoic (Ahda) acyl moiety, these new compounds are members of an extremely rare sub-class containing the β-amino acid residue 3-amino-2-hydroxy-octanoic acid (Ahoa). Additionally, microginins 680 and 646 (di-chloro and mono-chloro, respectively) represent the first halogenated examples of the Ahoa group in a natural product.
Halfspace Matrices

A halfspace matrix is a Boolean matrix A with rows indexed by linear threshold functions f , columns indexed by inputs x isin {-1,1}n, and the entries given by Af ,x = f (x). We demonstrate the potential of halfspace matrices as tools to answer nontrivial open questions. (1) (Communication complexity) We exhibit a Boolean function f with discrepancy Omega(1/n4) under every product distribution but O(radicn /2n/4}) under a certain non-product distribution. This partially solves an open problem of Kushilevitz and Nisan. (2) (Complexity of sign matrices) We construct a matrix A isin {-1,1}NtimesN logN with dimension complexity logN but margin complexity Omega(N1/4/radic{log N}). This gap is an exponential improvement over previous work. As an application to circuit complexity, we prove an Omega(2n/4/(dradicn)) circuit lower bound for computing halfspaces by a majority of an arbitrary set of d gates. This complements a result of Goldmann, Hastad, and Razborov. In addition, we prove new results on the complexity measures of sign matrices, complementing recent work by Linial et al.(3) (Learning theory) We give a short and simple proof that the statistical-query (SQ) dimension of halfspaces in n dimensions is less than 2(n+1)2 under all distributions (with n+1 being a trivial lower bound). This improves on the nO(1) estimate from the fundamental paper of Blum et al. Finally, we motivate our learning-theoretic result for the complexity community by showing that SQ dimension estimates for natural classes of Boolean functions can resolve major open problems in complexity theory. Specifically, we show that an exp(2(logn) o(1) ) upper bound on the SQ dimension of AC0 would imply an explicit language in PSPACEcc\PHcc.
Architectural and operational considerations emerging from hybrid RF-optical network loading simulations

A technology demonstration of free space optical communication at interplanetary distances is planned via one or more future NASA deep-space missions. Such demonstrations will "pave the way" for operational use of optical communications on future robotic/potential Human missions. Hence, the Deep Space Network architecture will need to evolve. Preliminary attempts to model the anticipated future mission set and simulate how well it loads onto assumed architectures with combinations of RF and optical apertures have been evaluated. This paper discusses the results of preliminary loading simulations for hybrid RF-optical network architectures and highlights key mission and ground infrastructure considerations that emerge.
Is green growth relevant for poor economies

To be relevant to developing countries, green growth must be reconciled with the two key structural features of natural resource use and poverty in these countries. First, primary products account for the majority of their export earnings, and they are unable to diversify from primary production. Second, many economies have a substantial share of their rural population located on less favored agricultural land and in remote areas, thus encouraging “geographic” poverty traps. If green growth is to be a catalyst for economy-wide transformation and poverty alleviation in developing countries, then it must be accompanied by policies aimed directly at overcoming these two structural features. Policies and reforms should foster forward and backward linkages of primary production, enhance its integration with the rest of the economy, and improve opportunities for innovation and knowledge spillovers. Rural poverty, especially the persistent concentration of the rural poor on less favored agricultural lands and in remote areas, needs to be addressed by additional targeted policies and investments, and where necessary, policies to promote rural-urban migration.