cssi/SciSciGPT-SciSciNet huggingface dataset:
Spatialities of data: mapping social media ‘beyond the geotag’

As emerging sources of so-called ‘big data’ are increasingly utilized in order to understand social and spatial processes, so too have these new data sources become the subject of harsh criticism from more critically-oriented geographers and social scientists. This paper argues that one of the major issues preventing a more productive dialogue between critical human geographers and those already engaging in the mapping and analysis of these new data sources is around the ways that space and spatiality are conceptualized in social media mapping. As such, this paper draws on and extends earlier critiques of the ‘spatial ontology of the geotag’, in which the geographic analysis of geotagged social media data over-privileges the single latitude/longitude coordinate pair attached to each individual data point, often leading to the kind of simplistic mappings and interpretations prevalent today. The goals of this paper are two-fold: first, to demonstrate how the spatial ontology of the geotag is implicitly operationalized within mainstream social media mapping exercises, and how this understanding of space remains incongruent with existing conceptions of space drawn from human geography. Second, using the example of tweeting in the wake of the August 2014 killing of an unarmed African–American teenager by a police officer in Ferguson, Missouri, this paper demonstrates how a more geographically-situated analysis of this kind of data, inspired by relational or multidimensional conceptualizations of space, can yield alternative understandings of the social processes embedded in such data.
Wear of Metal by Rubber

Rates of wear have been determined for steel and bronze scrapers sliding over rubber surfaces. The wear rates were found to depend strongly upon the particular elastomer used, varying by orders of magnitude even though the other ingredients in the compound and the physical properties of the rubber were largely unchanged. In the absence of oxygen the metal scrapers were found to wear away much faster in general; by a factor of 5 to 50 times, depending upon the elastomer. Butyl rubber was anomalous in this respect, however, causing three times greater wear in air than in nitrogen. These diverse observations are attributed to the direct attack upon metals of free radical species generated by mechanical rupture of elastomer molecules during abrasion. The rate of metal wear is closely correlated with the stability of polymeric radicals formed in this way. When the radical is highly reactive it is thought to take part primarily in internal reactions and thus cause little wear of the scraper. On the other hand, relatively stable polymer radicals appear to attack metals vigorously.
Deformation of a single red blood cell in bounded Poiseuille flows.

Deformation of a red blood cell (RBC) in bounded two-dimensional Poiseuille flows is studied by using an immersed boundary method (IBM). An elastic spring model is applied to simulate the skeleton structure of a RBC membrane. As a benchmarking test, the dynamical behavior of a single RBC under a simple shear flow has been validated. Then we focus on investigating the motion and the deformation of a single RBC in Poiseuille flows by varying the swelling ratio (${s}^{*}$), the initial angle of the long axis of the cell at the centerline ($\ensuremath{\phi}$), the maximum velocity at the centerline of fluid flow (${u}_{\text{max}}$), the membrane bending stiffness of a RBC (${k}_{b}$), and the height of the microchannel ($H$). Two motions of oscillation and vacillating breathing (swing) of a RBC are observed in both narrow and wide channels. The strength of the vacillating-breathing motion depends on the degree of confinement and the value of ${u}_{\text{max}}$. A RBC exhibits a strong vacillating-breathing motion as the degree of confinement is larger or the value of ${u}_{\text{max}}$ is higher. For the same degree of confinement, the vacillating-breathing motion appears to be relatively weaker but persists longer as the value of ${u}_{\text{max}}$ is lower. The continuation of shape change from the slippery to the parachute by varying the value of ${u}_{\text{max}}$ is obtained for the biconcave shape cell in a narrower channel. In particular, parachute shape and bulletlike shape, depending on the angle $\ensuremath{\phi}$, coexist for the elliptic shape cell given initially with lower ${u}_{\text{max}}$ in a narrower channel.
Pd(II)-Catalyzed Ortho-Trifluoromethylation of Benzylamines

The Pd(II)-catalyzed ortho-C–H trifluoromethylation of benzylamines has been achieved utilizing an electrophilic CF3 reagent. Additives, such as H2O and Ag2O, were found to be crucial for obtaining good yields. This protocol will be useful in medicinal chemistry for the preparation of ortho-trifluoromethyl-substituted benzylamines.
The Surface Chemistry of Atomic Layer Depositions of Solid Thin Films

Atomic layer deposition (ALD) is one of the most promising methodologies available for the growth of solid thin films conformally on complex topographies and with atomic-level control on thickness. However, as a chemical process, ALD can lead to the incorporation of impurities and to the growth of poor-quality films. Here we discuss some possible complications associated with the chemistry of ALD, including its ill-defined stoichiometry, the stepwise and extensive surface conversion possible with the ligands of most ALD metalorganic precursors, the need for the reduction or oxidation of the deposited elements, the poor understanding of the role of the coreactants, the dominant activity of specific minority surface sites in starting ALD processes, and the development of complex layered or three-dimensional structures within the deposited films. The resolution of these issues should help with the development of a more systematic approach for the selection of ALD precursors and for the design of ALD processes.
Earnings Smoothing Activities of Firms to Manage Credit Ratings

This paper explores how incentives to maintain or improve credit ratings affect corporate financial reporting. Credit ratings have significant cost...
Managers’ Use of Language Across Alternative Disclosure Outlets: Earnings Press Releases versus MD&A*

We use textual-analysis software to quantify the language used in earnings press releases and the corresponding Management Discussion and Analysis (MD&A) for approximately 13,000 firm quarters between 1998 and 2003. Analyzing two narrative disclosures in which managers describe firm performance for the same quarter allows us to examine managers’ use of language across alternative communication outlets. Our general prediction, which relies on prior literature suggesting that there is a greater market response to information disclosed in an earnings announcement press release versus an SEC filing, is that managers disclose less pessimistic language and more optimistic language in earnings press releases relative to the corresponding MD&A disclosures. We first document that firms exhibit significantly lower levels of pessimistic language and higher levels of optimistic language in earnings press releases relative to the MD&A. We then construct a measure of the proportion of total pessimistic language reported in an earnings press release relative to the corresponding MD&A and find this proportional measure is negatively associated with the intensity of managers’ strategic reporting incentives. In additional analyses, we find a negative association between the level of pessimistic language in the MD&A and future firm performance, controlling for pessimistic language in the corresponding earnings press release. This evidence supports our assertion that managers disclose pessimistic language in the MD&A that provides information incremental to that in the corresponding earnings press release. Overall, our results are consistent with managers’ use of alternative communication outlets as part of a strategy to influence the market’s response to information disclosed.
Nickel-Catalyzed Negishi Alkylations of Styrenyl Aziridines

A nickel-catalyzed cross-coupling reaction between N-sulfonyl aziridines and organozinc reagents is reported. The catalytic system comprises an inexpensive and air-stable Ni(II) source and dimethyl fumarate as ligand. Regioselective synthesis of β-substituted amines is possible under mild and functional-group-tolerant conditions. The stereoselectivity of the reaction is consistent with a stereoconvergent mechanism wherein the sulfonamide directs C-C bond formation.
Nickel-Catalyzed Intramolecular C-O Bond Formation: Synthesis of Cyclic Enol Ethers.

An efficient and exceptionally mild intramolecular nickel-catalyzed carbon–oxygen bond-forming reaction between vinyl halides and primary, secondary, and tertiary alcohols has been achieved. Zinc powder was found to be an essential additive for obtaining high catalyst turnover and yields. This operationally simple method allows direct access to cyclic vinyl ethers in high yields in a single step.
Morphological and biochemical studies of the structure of the vitreous and the zonular fibres.

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Does leaving school in an economic downturn persistently affect body weight? evidence from panel data

In this study I test whether leaving school when the state unemployment rate is high persistently affects body weight. Because the time and location of school leaving are potentially endogenous, I predict the economic conditions at school leaving with instruments based on birth date and residence at age 14. My findings show that by age 40 men (women) who left school when the state unemployment rate was high have lower (higher) body weight.
Development of Non-C2-symmetric ProPhenol Ligands. The Asymmetric Vinylation of N-Boc Imines

The development and application of a new generation of non-C2-symmetric ProPhenol ligands is reported herein. Rational design of the ProPhenol ligand paved the way to the first catalytic and asymmetric vinylation of N-Boc imines via hydrozirconation giving rise to valuable allylic amines in excellent yields and enantioselectivities. The utility of this method was demonstrated by developing the shortest reported asymmetric synthesis of the selective serotonine reuptake inhibitor (SSRI) (−)-dapoxetine.
Photo Aesthetics Ranking Network with Attributes and Content Adaptation

Real-world applications could benefit from the ability to automatically generate a fine-grained ranking of photo aesthetics. However, previous methods for image aesthetics analysis have primarily focused on the coarse, binary categorization of images into high- or low-aesthetic categories. In this work, we propose to learn a deep convolutional neural network to rank photo aesthetics in which the relative ranking of photo aesthetics are directly modeled in the loss function. Our model incorporates joint learning of meaningful photographic attributes and image content information which can help regularize the complicated photo aesthetics rating problem.
The Morse minimal system is nearly continuously Kakutani equivalent to the binary odometer

Ergodic homeomorphisms T and S of Polish probability spaces X and Y are evenly Kakutani equivalent if there is an orbit equivalence ϕ: X 0 → Y 0 between full measure subsets of X and Y such that, for some A ⊂ X 0 of positive measure, ϕ restricts to a measurable isomorphism of the induced systems T A and S ϕ(A). The study of even Kakutani equivalence dates back to the seventies, and it is well known that any two zero-entropy loosely Bernoulli systems are evenly Kakutani equivalent. But even Kakutani equivalence is a purely measurable relation, while systems such as the Morse minimal system are both measurable and topological. Recently del Junco, Rudolph and Weiss studied a new relation, called nearly continuous Kakutani equivalence. A nearly continuous Kakutani equivalence is an even Kakutani equivalence where also X 0 and Y 0 are invariant G δ sets, A is within measure zero of both open and closed, and ϕ is a homeomorphism from X 0 to Y 0. It is known that nearly continuous Kakutani equivalence is strictly stronger than even Kakutani equivalence, and nearly continuous Kakutani equivalence is the natural strengthening of even Kakutani equivalence to the nearly continuous category—the category of maps that are continuous after sets of measure zero are removed. In this paper, we show that the Morse minimal substitution system is nearly continuously Kakutani equivalent to the binary odometer.
Interdependency of transmission and distribution pricing

Distribution markets are among the prospect being considered for the future of power systems. They would facilitate integration of distributed energy resources (DERs) and microgrids via a market mechanism and enable them to monetize services they can provide. This paper follows the ongoing work in implementing the distribution market operator (DMO) concept, and its clearing and settlement procedures, and focuses on investigating the pricing conducted by the DMO. The distribution locational marginal prices (D-LMPs) and their relationship with the transmission system locational marginal prices (T-LMPs) are subject of this paper. Numerical simulations on a test distribution system exhibit the benefits and drawbacks of the proposed DMO pricing processes.
Femtosecond Laser Melting of Graphite

Although graphite sublimes when heated adiabatically at atmospheric pressure, molten carbon is created under pulsed laser irradiation There have been conflicting claims, however, that the liquid phase is electrically insulating2,3 or conducting4,5 The former claim is based on time-resolved optical reflectivity measurements2 using 20 ps. pulses, in which reflectivity rapidly decreased after excitation above the melting threshold, suggesting creation of an insulating liquid phase.
Impact of Ethnic Civil Conflict on Migration of Skilled Labor

We reevaluate the hypothesis and empirical result that ethnic civil wars lead to higher skilled emigration [Bang and Mitra in East Econ J 39(3):387–401, 2013]. We develop a simple conceptual framework that predicts contrasting results depending upon if the economy is assumed to be agglomerating in skilled labor or non-agglomerating with network effects. In the latter case, non-ethnic wars may lead to higher skilled emigration. A regression model that accounts for the time-varying definition of migration and includes important explanatory variables shows that non-ethnic wars as opposed to ethnic wars may lead to more skilled emigration.
Honeycomb-like S = 5/2 Spin–Lattices in Manganese(II) Vanadates

New complex manganese vanadate materials were synthesized as high-quality single crystals in multi-millimeter lengths using a high-temperature, high-pressure hydrothermal method. One compound, Mn5(VO4)2(OH)4, was grown from Mn2O3 and V2O5 in 3 M CsOH at 580 °C and 1.5 kbar. Changing the mineralizer to 1 M CsOH/3MCsCl leads to the formation of another product, Mn6O(VO4)2(OH). Both compounds were structurally characterized by single-crystal X-ray diffraction (Mn5(VO4)2(OH)4: C2/m, Z = 2, a = 9.6568(9) A, b = 9.5627(9) A, c = 5.4139(6) A, β = 98.529(8)°; Mn6O(VO4)2(OH): P21/m, Z = 2, a = 8.9363(12) A, b = 6.4678(8) A, c = 10.4478(13) A, β = 99.798(3)°), revealing interesting low-dimensional transition-metal features. Mn5(VO4)2(OH)4 possesses complex honeycomb-type Mn–O layers, built from edge-sharing [MnO6] octahedra in the bc plane, with bridging vanadate groups connecting these layers along the a-axis. Mn6O(VO4)2(OH) presents a more complicated structure with both octahedral [MnO6] and trigonal bipyramidal...
Transverse spin observables in hard-scattering hadronic processes within collinear factorization

We review what is currently known about the transverse spin structure of hadrons, in particular from observables that can be analyzed within a collinear framework. These effects have been around for 40 years and represent a critical test of perturbative QCD. We look at both proton–proton and lepton–nucleon collisions for various final states. While the main focus is on transverse single-spin asymmetries, we also discuss how longitudinal-transverse double-spin asymmetries offer a complimentary, yet equally important, source of information on the quark–gluon content of hadrons. We also summarize some recent progress in solidifying the theoretical formalism behind these observables and give an outlook on future directions of research.
BONE GRAFTS AND THEIR SUBSTITUTES: UNDERSTANDING THE THREE O'S

Bone is a dynamic organ with remarkable regenerative properties seen only otherwise in the liver. However, bone healing requires vascularity, stability, growth factors, a matrix for growth, and viable cells to obtain effective osteosynthesis. We rely on these principles not only to heal fractures, but also achieve healing of benign bone defects. Unfortunately, we are regularly confronted with situations where the local environment and tissue is insufficient and we must rely on our “biologic tool box.” When the process of bone repair requires additional assistance, we often look to bone grafting to provide an osteoconductive, osteoinductive, and/or osteogenic environment to promote bone healing and repair. The primary workhorses of bone grafting includes autogenous bone, cadaver allograft, and bone graft substitutes. Among the first types of bone graft used and still used in large quantities today include autogenous and cadaver allograft bone. Allografts are useful because it is present in multiple forms that conform to the desired situation. But autogenous bone graft is considered the gold standard because it possesses all the fundamental properties to heal bone. However, it has been associated with high rates of donor site morbidity and typically requires an inpatient hospitalization following the procedure only adding to the associated costs. The first bone graft substitute use was calcium sulfate in 1892, and over the past 122 years advancements have achieved improved material properties of calcium sulfate and helped usher in additional bioceramics for bone grafting. Today there are predominantly 4 types of bioceramics available, which include calcium sulfate, calcium phosphate, tricalcium phosphate, and coralline hydroxyapatite. They come in multiple forms ranging from pellets and solid blocks to injectable and moldable putty. In comparison to autogenous bone graft, the primary limitation of bioceramics are the lack of osteogenic and osteoinductive properties. Bioceramics work by creating an osteoconductive scaffold to promote osteosynthesis. The options of bone graft substitutes don9t end with these four types of bioceramics. Composite bioceramics take advantage of the differing biomechanical properties of these four basis types of bioceramics to develop improved materials. To overcome the lack of osteoinductive and osteogenic properties growth factors or bone marrow aspirate can be added to the bioceramic. As a result, the list of combinations available in our “biologic tool box” continues to expand. More than 20 BMPs have been identified, but only BMP-2 and BMP-7 have FDA approval. As we look forward to areas of future research and need within orthobiologics, some will likely come in the near future while others are much further in the future. We will continue to strive for the ideal bone graft substitute, which will have similar osteoinductive properties as autograft. The ultimate bone graft substitute will likely involve stem cells because it will allow an alternative to autogenous bone with the same osteogenic potential.
Transport exponents of states with large support

We investigate spreading rates of one-dimensional quantum states under the Schrodinger time-evolution. The focus of this paper is on the states that either have finite support or decay exponentiall...
Understanding Considerate Systems - UCS (Pronounced: You See Us)

Interactions between people occur in a social realm. On the other hand, "things", including devices for communication and computation, are generally socially deficient. Imagine socially aware systems moving from an interruption model of communication to an introduction model. To create considerate systems, there is a need to model social context, social behavior, and communication goals.This paper describes early systems that work to understand and eliminate the socially disruptive qualities of the ubiquitous systems people increasingly use and rely on in all aspects of their personal, educational, social and business lives. We show performance improving systems: an instant message arrives after you have finished typing a sentence, not while you are forming it; a car waits for you to complete a difficult maneuver before giving you distracting feedback.This work relies on dynamic task, user, system, and communication models. The goal is to stimulate more work to understand and create considerate systems. Such systems will improve people's experience and performance. Social responsiveness can become the norm for the technology that pervades our lives.
Gluino reach and mass extraction at the LHC in radiatively-driven natural SUSY

Radiatively-driven natural SUSY (RNS) models enjoy electroweak naturalness at the 10% level while respecting LHC sparticle and Higgs mass constraints. Gluino and top-squark masses can range up to several TeV (with other squarks even heavier) but a set of light Higgsinos are required with mass not too far above $$m_h\sim 125$$ GeV. Within the RNS framework, gluinos dominantly decay via $$\tilde{g}\rightarrow t\tilde{t}_1^{*},\ \bar{t}\tilde{t}_1 \rightarrow t\bar{t}\widetilde{Z}_{1,2}$$ or $$t\bar{b}\widetilde{W}_1^-+c.c.$$ , where the decay products of the higgsino-like $$\widetilde{W}_1$$ and $$\widetilde{Z}_2$$ are very soft. Gluino pair production is, therefore, signaled by events with up to four hard b-jets and large $$\not \!\!{E_T}$$ . We devise a set of cuts to isolate a relatively pure gluino sample at the (high-luminosity) LHC and show that in the RNS model with very heavy squarks, the gluino signal will be accessible for $$m_{\tilde{g}} < 2400 \ (2800)$$ GeV for an integrated luminosity of 300 (3000) fb $$^{-1}$$ . We also show that the measurement of the rate of gluino events in the clean sample mentioned above allows for a determination of $$m_{\tilde{g}}$$ with a statistical precision of 2–5% (depending on the integrated luminosity and the gluino mass) over the range of gluino masses where a 5 $$\sigma $$ discovery is possible at the LHC.
A spatial branch-and-cut method for nonconvex QCQP with bounded complex variables

We develop a spatial branch-and-cut approach for nonconvex quadratically constrained quadratic programs with bounded complex variables (CQCQP). Linear valid inequalities are added at each node of the search tree to strengthen semidefinite programming relaxations of CQCQP. These valid inequalities are derived from the convex hull description of a nonconvex set of $$2 \times 2$$ positive semidefinite Hermitian matrices subject to a rank-one constraint. We propose branching rules based on an alternative to the rank-one constraint that allows for local measurement of constraint violation. Closed-form bound tightening procedures are used to reduce the domain of the problem. We apply the algorithm to solve the alternating current optimal power flow problem with complex variables as well as the box-constrained quadratic programming problem with real variables.
Quasi-Newton methods: superlinear convergence without line searches for self-concordant functions

We consider the use of a curvature-adaptive step size in gradient-based iterative methods, including quasi-Newton methods, for minimizing self-concordant functions, extending an approach first prop...
Outcomes of submucosal (T1b) esophageal adenocarcinomas removed by endoscopic mucosal resection.

Outcomes of submucosal (T1b) esophageal adenocarcinomas removed by endoscopic mucosal resection
Rethinking Measurement of Pay Disparity and its Relation to Firm Performance

ABSTRACT I develop measures of firm-level pay disparity and examine their relation to firm performance. Using comprehensive compensation data for a large sample of firms, I find no statistically si...
Flux corrected finite volume scheme for preserving scalar boundedness in reacting large-eddy simulations

Preserving scalar boundedness is an important prerequisite to performing large-eddy simulations of turbulent reacting flows. A number of popular combustion models use a conserved-scalar, mixture-fraction to parameterize reactions that, by definition, is bound between zero and one. To avoid unphysical clipping, the numerical scheme solving the conserved-scalar transport equation must preserve these bounds, while minimizing the amount of numerical diffusivity. To this end, a flux correction method is presented and applied to the quadratic-upwind biased interpolative convective scheme that ensures preservation of the scalar's physical bounds while retaining the low numerical diffusivity of the original quadratic-upwind biased interpolative convective scheme. It is demonstrated that this bounded quadratic-upwind biased interpolative convective scheme outperforms the third-order weighted essentially nonoscillatory scheme in maintaining spatial accuracy and reducing numerical dissipation errors both in generic test cases as well as direct numerical simulation of canonical flows.
On the Cauchy completeness of the constructive Cauchy reals

It is consistent with constructive set theory (without Countable Choice, clearly) that the Cauchy reals (equivalence classes of Cauchy sequences of rationals) are not Cauchy complete. Related results are also shown, such as that a Cauchy sequence of rationals may not have a modulus of convergence, and that a Cauchy sequence of Cauchy sequences may not converge to a Cauchy sequence, among others.
Void control in the crystallization of lithium fluoride

Abstract The effect of tungsten-coated graphite fibers on the radiant heat transfer characteristics of salt-fiber composites was studied by measuring the onset of melting as a function of applied furnace power. As the fiber concentration was increased from 0 wt% to 5.40 wt% fiber, the furnace temperature required to melt the lithium fluoride also increased. Upon cooling, each of the crystalline salt-fiber composites were cut open with a diamond saw to expose the void. Optical photographs of the voids revealed a trend in void location and size, with the largest void, and the least change in the outer dimension of the boule upon cooling, occuring in the sample with the most fiber.
R-parity violation in superstring derived models

Abstract The ALEPH Collaboration has recently reported a significant excess of four-jet events at the LEP 1.5 and LEP 2 experiments. While not yet confirmed by the other Collaborations, it was recently proposed that this excess may be explained by certain R-parity violating operators in supersymmetric models. R-parity violating operators introduce the danger of inducing rapid proton decay. I discuss how the operators required to explain the ALEPH four jet events may arise from superstring derived models without inducing rapid proton decay.
Catching MPC Cheaters: Identification and Openability

Secure multi-party computation (MPC) protocols do not completely prevent malicious parties from cheating or disrupting the computation. We augment MPC with three new properties to discourage cheating. First is a strengthening of identifiable abort, called completely identifiable abort, where all parties who do not follow the protocol will be identified as cheaters by each honest party. The second is completely identifiable auditability, which means that a third party can determine whether the computation was performed correctly (and who cheated if it was not). The third is openability, which means that a distinguished coalition of parties can recover the MPC inputs.
Internationally comparable mathematics scores for fourteen african countries

Abstract Internationally comparable test scores play a central role in both research and policy debates on education. However, the main international testing regimes, such as PISA, TIMSS, or PIRLS, include almost no low-income countries. Instead, many developing countries opt for regional assessments sponsored by the United Nations. This paper exploits an overlap between the regional test for Southern and Eastern Africa, SACMEQ, and the TIMSS test – in both country coverage, and questions asked – to assesses the feasibility of constructing global learning metrics by equating regional and international scales. I find considerable variance when comparing three commonly-used equating methods, suggesting precise country rankings are unreliable. Across all methodologies, however, learning levels in this sample of African countries are consistently (a) low in absolute terms, by roughly one-and-a-half standard deviations or more compared to OECD pupils of a similar age; (b) significantly lower than predicted by African per capita GDP levels; and (c) converging slowly, if at all, to the rest of the world during the 2000s. The robustness of these simple facts suggests even crude linking methods may suffice for many international policy questions, such as tracking the UN’s development goals.
Strict Liability’s Criminogenic Effect

It is easy to understand the apparent appeal of strict liability to policymakers and legal reformers seeking to reduce crime: if the criminal law can do away with its traditional culpability requirement, it can increase the likelihood of conviction and punishment of those who engage in prohibited conduct or bring about prohibited harm or evil. And such an increase in punishment rate can enhance the crime-control effectiveness of a system built upon general deterrence or incapacitation of the dangerous. Similar arguments support the use of criminal liability for regulatory offenses. Greater punishment rates suggest greater compliance. But this analysis fails to appreciate the crime-control costs of strict liability. By explicitly providing for punishment in the absence of moral blameworthiness, the law undermines its moral credibility with the community and thereby provokes subversion and resistance instead of the cooperation and acquiescence it needs for effective crime control. More importantly, the system’s lost moral credibility undermines the law’s ability to harness the powerful forces of stigmatization, social influence, and internalized norms. Given the serious limitations inherent in the real-world application of general deterrence and preventive detention programs, the most effective crime-control strategy is to build the criminal law’s reputation for being just, which means avoiding the use of strict liability.
Reversed citations and the localization of knowledge spillovers

Spillover of knowledge is considered to be an important cause of agglomeration of inventive activity. Many studies argue that knowledge spillovers are localized based on the observation that patents tend to cite nearby patents disproportionately. Specifically, patent citations are typically interpreted as marking the transmission of knowledge from the cited invention to the citing invention. The localization of patent citations is therefore taken as evidence that such knowledge transmission is also localized. Localization of knowledge transmission, however, may not be the only reason that patent citations are localized. Using a set of citations that are unlikely to be associated with knowledge transmission from the cited to the citing invention, we present evidence that challenges the view that localization of citations is driven by localized knowledge transmission. While we are silent on the question of whether knowledge transmission is localized, to the extent that such localization exists, we argue that it is unlikely to be captured by patent citations.
A Tale of Two Cities: An Examination of Medallion Prices in New York and Chicago

This paper examines the institution of taxicab medallions in two of the largest cities of the U.S.—New York and Chicago—and changes in the prices of those medallions during the period 2009–2016 (for New York City) and 2007–2016 (for Chicago). We document a drop of roughly 50% in the prices of these medallions in New York and roughly 80% in Chicago from their peak in 2013/2014 to the present. We also find that medallion prices are positively correlated with taxicab revenues (for New York City) and negatively correlated with proxies for the intensity of adoption of Uber and Lyft and interest rates in both cities.
An Analytic Criterion for Turbulent Disruption of Planetary Resonances

Mean motion commensurabilities in multi-planet systems are an expected outcome of protoplanetary disk-driven migration, and their relative dearth in the observational data presents an important challenge to current models of planet formation and dynamical evolution. One natural mechanism that can lead to the dissolution of commensurabilities is stochastic orbital forcing, induced by turbulent density fluctuations within the nebula. While this process is qualitatively promising, the conditions under which mean motion resonances can be broken are not well understood. In this work, we derive a simple analytic criterion that elucidates the relationship among the physical parameters of the system, and find the conditions necessary to drive planets out of resonance. Subsequently, we confirm our findings with numerical integrations carried out in the perturbative regime, as well as direct N-body simulations. Our calculations suggest that turbulent resonance disruption depends most sensitively on the planet–star mass ratio. Specifically, for a disk with properties comparable to the early solar nebula with α = 10(-2), only planet pairs with cumulative mass ratios smaller than (m_1 + m_2)/M ≾ 10^(-5) ~ 3M⊕/M⊙ are susceptible to breaking resonance at semimajor axis of order a ~ 0.1 au. Although turbulence can sometimes compromise resonant pairs, an additional mechanism (such as suppression of resonance capture probability through disk eccentricity) is required to adequately explain the largely non-resonant orbital architectures of extrasolar planetary systems.
Shrinking targets for discrete time flows on hyperbolic manifolds

We prove dynamical Borel Canteli Lemmas for discrete time homogenous flows hitting a sequence of shrinking targets in a hyperbolic manifold. These results apply to both diagonalizable and unipotent flows, and to any family of measurable shrinking targets in the manifold. As a special case, we establish logarithm laws for the first hitting times to shrinking balls and shrinking cusp neighborhoods, refining and improving on perviously known results.
Object-Detecting Neurons in Drosophila

Many animals rely on vision to detect objects such as conspecifics, predators, and prey. Hypercomplex cells found in feline cortex and small target motion detectors found in dragonfly and hoverfly optic lobes demonstrate robust tuning for small objects, with weak or no response to larger objects or movement of the visual panorama [1-3]. However, the relationship among anatomical, molecular, and functional properties of object detection circuitry is not understood. Here we characterize a specialized object detector in Drosophila, the lobula columnar neuron LC11 [4]. By imaging calcium dynamics with two-photon excitation microscopy, we show that LC11 responds to the omni-directional movement of a small object darker than the background, with little or no responses to static flicker, vertically elongated bars, or panoramic gratings. LC11 dendrites innervate multiple layers of the lobula, and each dendrite spans enough columns to sample 75° of visual space, yet the area that evokes calcium responses is only 20° wide and shows robust responses to a 2.2° object spanning less than half of one facet of the compound eye. The dendrites of neighboring LC11s encode object motion retinotopically, but the axon terminals fuse into a glomerular structure in the central brain where retinotopy is lost. Blocking inhibitory ionic currents abolishes small object sensitivity and facilitates responses to elongated bars and gratings. Our results reveal high-acuity object motion detection in the Drosophila optic lobe.
Impact of Vitamin A and Carotenoids on the Risk of Tuberculosis Progression.

Background Low and deficient levels of vitamin A are common in low- and middle-income countries where tuberculosis burden is high. We assessed the impact of baseline levels of vitamin A and carotenoids on tuberculosis disease risk. Methods We conducted a case-control study nested within a longitudinal cohort of household contacts (HHCs) of pulmonary tuberculosis case patients in Lima, Peru. We defined case patients as human immunodeficiency virus (HIV)-negative HHCs with blood samples in whom tuberculosis disease developed ≥15 days after enrollment of the index patient. For each case patient, we randomly selected 4 controls from among contacts in whom tuberculosis disease did not develop, matching for sex and year of age. We used conditional logistic regression to estimate odds ratios for incident tuberculosis disease by vitamin A and carotenoids levels, controlling for other nutritional and socioeconomic factors. Results Among 6751 HIV-negative HHCs with baseline blood samples, 192 had secondary tuberculosis disease during follow-up. We analyzed 180 case patients with viable samples and 709 matched controls. After controlling for possible confounders, we found that baseline vitamin A deficiency was associated with a 10-fold increase in risk of tuberculosis disease among HHCs (adjusted odds ratio, 10.53; 95% confidence interval, 3.73-29.70; P < .001). This association was dose dependent, with stepwise increases in tuberculosis disease risk with each decreasing quartile of vitamin A level. Conclusions Vitamin A deficiency strongly predicted the risk of incident tuberculosis disease among HHCs of patients with tuberculosis. Vitamin A supplementation among individuals at high risk of tuberculosis may provide an effective means of preventing tuberculosis disease.
Diffusion and Solubility of Tritium in Path a Prime Candidate Alloy

The tritium recoil injection technique was used to determine the tritium diffusion coefficient for Path A Prime Candidate Alloy (PCA) over the temperature range 323K to 523K. Dissolution tritium counting of samples saturated in a tritium-hydrogen mixture was used to determine the tritium solubility for PCA over the temperature range 673K to 973K. No evidence of high energy trapping due to the titanium carbide precipitates in PCA was seen.
400 VERSUS 700 CGY RADIATION IN PREVENTION OF HETEROTOPIC OSSIFICATION AFTER TOTAL HIP ARTHROPLASTY

Background Heterotopic ossification (HO) is a known complication following total hip arthroplasty, with increased incidence in certain patient populations. Current prophylaxis options include oral non-steroidal anti-inflammatory drugs (NSAIDs) and radiation therapy, but an optimal radiation protocol has yet to be clearly defined. We performed a randomized, double-blinded clinical trial in high-risk total hip arthroplasty patients to determine the efficacy of 400 cGy versus 700 cGy doses of radiation. Methods 147 patients at high risk for HO undergoing total hip arthroplasty (THA) at Rush-St. Luke's- Presbyterian medical center were randomized to either a single 400 cGy or 700 cGy dose of radiation. High risk was defined as diagnosis of diffuse idiopathic skeletal hyperostosis (DISH), hypertrophic osteoarthritis, ankylosing spondylitis, or history of previous heterotopic ossification. Radiation was administered over a 14 × 6 cm area of soft tissue and given on the first or second post-operative day. A blinded reviewer graded anterior-posterior (AP) and lateral radiographs taken immediately post-operatively and at a minimum of 6 months post-operatively. Progression was defined as an increase in Brooker classification from the immediate post-operative to the long-term post-operative radiograph. Operative data including surgical approach, use of cemented implants, revision surgery, and post-operative range of motion data were also collected. Results A significantly greater portion of patients who received the 400 cGy dose demonstrated progression of HO than patients who received the 700 cGy dose. No pre-operative factors were associated with a higher rate of progression. Patients who progressed had less flexion on physical exam than patients who did not progress, but this was not clinically significant. Conclusion To the authors' knowledge this is the largest randomized prospective study to date comparing two single-dosages of radiation treatment. 700 cGy demonstrates superiority over 400 cGy in preventing HO formation following total hip arthroplasty in high-risk patients and may be the more effective treatment in this population.
Depth Separation for Neural Networks.

Let $f:\mathbb{S}^{d-1}\times \mathbb{S}^{d-1}\to\mathbb{S}$ be a function of the form $f(\mathbf{x},\mathbf{x}') = g(\langle\mathbf{x},\mathbf{x}'\rangle)$ for $g:[-1,1]\to \mathbb{R}$. We give a simple proof that shows that poly-size depth two neural networks with (exponentially) bounded weights cannot approximate $f$ whenever $g$ cannot be approximated by a low degree polynomial. Moreover, for many $g$'s, such as $g(x)=\sin(\pi d^3x)$, the number of neurons must be $2^{\Omega\left(d\log(d)\right)}$. Furthermore, the result holds w.r.t.\ the uniform distribution on $\mathbb{S}^{d-1}\times \mathbb{S}^{d-1}$. As many functions of the above form can be well approximated by poly-size depth three networks with poly-bounded weights, this establishes a separation between depth two and depth three networks w.r.t.\ the uniform distribution on $\mathbb{S}^{d-1}\times \mathbb{S}^{d-1}$.
Sparse Additive Models

Summary. We present a new class of methods for high dimensional non-parametric regression and classification called sparse additive models. Our methods combine ideas from sparse linear modelling and additive non-parametric regression. We derive an algorithm for fitting the models that is practical and effective even when the number of covariates is larger than the sample size. Sparse additive models are essentially a functional version of the grouped lasso of Yuan and Lin. They are also closely related to the COSSO model of Lin and Zhang but decouple smoothing and sparsity, enabling the use of arbitrary non-parametric smoothers. We give an analysis of the theoretical properties of sparse additive models and present empirical results on synthetic and real data, showing that they can be effective in fitting sparse non-parametric models in high dimensional data.
TVA pilot-plant phosphate flotation conditioning study.

TVA conducted an extensive test program in its 1,000-pound-per-hour phosphate beneficiation pilot plant to study the effects of major variables in the conditioning step prior to phosphate flotation. Florida rock fine flotation feeds of 14 and 18 bone phosphate of lime (BPL) from the Bone Valley formation were tested. During Phase I for each flotation feed, a full factorial design was used for the test series to evaluate the effects of agitation, retention time, and solids content on P2O5 recovery and product grade. In Phase II, a qualitative test study was completed of several additional variables including agitator flow direction, slurry feed position, use of baffles or no baffles, fuel oil to fatty acid ratio, and reagent dosage. The results of both test series were statistically analyzed and compared with those obtained from batch, laboratory-scale flotation tests of pilot plant conditioned samples. From the pilot-scale results, a mathematical model was developed relating product grade and P2O5 recovery to the major process variables.
Order Flow and Exchange Rate Dynamics in Continuous Time: New Evidence from Martingale Regression

The so-called “foreign exchange rate determination puzzle” has been a hard topic in international finance for several decades. The puzzle illustrates the weak explanatory power of macroeconomic-based models of the nominal exchange rate fluctuations. We investigate the foreign exchange rate determination puzzle in a continuous-time framework. Following the market microstructure literature, a simple model of the determination of foreign exchange rates is developed, and the model concludes a result which is essentially a continuous-time version of the equation in Evans and Lyons (2002a). For estimation, we take an advantage of a newly-developed econometric tool based on a time change from calendar to volatility time. With this new estimation methodology, our results indicate that the effect of order flow on exchange rate is significantly improved compared with the traditional econometric tools. Keywords: Order Flow; Time-Change Sampling; Martingale Estimator JEL Classifications : C22; G15; G17
Current guidelines for the evaluation and management of atopic dermatitis: A comparison of the Joint Task Force Practice Parameter and American Academy of Dermatology guidelines

Atopic dermatitis (AD) is a chronic pruritic inflammatory disease that commonly presents in the pediatric population. Although definitions and diagnosis of AD have largely been agreed upon, allergists and dermatologists have similar and divergent approaches to the management of AD. This review facilitated integration of the American Academy of Allergy, Asthma & Immunology/American College of Allergy, Asthma & Immunology Joint Task Force 2012 AD Practice Parameter and the 2014 American Academy of Dermatology guidelines to highlight the basic principles of AD management and discuss therapies and management of AD from the distinct perspectives of the allergist and dermatologist.