cssi/SciSciGPT-SciSciNet huggingface dataset:
Carbon Sequestration in Reclaimed Minesoils

Minesoils are drastically influenced by anthropogenic activities. They are characterized by low soil organic matter (SOM) content, low fertility, and poor physicochemical and biological properties, limiting their quality, capability, and functions. Reclamation of these soils has potential for resequestering some of the C lost and mitigating CO2 emissions. Soil organic carbon (SOC) sequestration rates in minesoils are high in the first 20 to 30 years after reclamation in the top 15 cm soil depth. In general, higher rates of SOC sequestration are observed for minesoils under pasture and grassland management than under forest land use. Observed rates of SOC sequestration are 0.3 to 1.85 Mg C ha− 1 yr− 1 for pastures and rangelands, and 0.2 to 1.64 Mg C ha− 1 yr− 1 for forest land use. Proper reclamation and postreclamation management may enhance SOC sequestration and add to the economic value of the mined sites. Management practices that may enhance SOC sequestration include increasing vegetative cover by de...
Singularity Robust Steering Logic for Redundant Single-Gimbal Control Moment Gyros

In this paper we investigate a singularity problem inherent in a system of redundant single-gimbal control moment gyros (CMGs). In particular, we present a simple yet effective way of passing through, and also escaping from, any internal singularities. The proposed approach is based on the so-called "singularity robust inverse," but it utilizes a nondiagonal weighting matrix in the mixed, two-norm and weighted least-squares minimization problem. The proposed steering logic effectively generates "deterministic dither signals" when the CMG system becomes near singular. Because the proposed CMG steering logic is based on the simple minimum two-norm, pseudoinverse solution, it does not explicitly avoid singularity encounters but it rather approaches and rapidly transits unavoidable singularities whenever needed. However, the proposed steering logic is not intended for special missions in which prescribed attitude trajectories are to be "exactly" tracked in the presence of internal singularities.
Automatic induction of bellman-error features for probabilistic planning

Domain-specific features are important in representing problem structure throughout machine learning and decision-theoretic planning. In planning, once state features are provided, domain-independent algorithms such as approximate value iteration can learn weighted combinations of those features that often perform well as heuristic estimates of state value (e.g., distance to the goal). Successful applications in real-world domains often require features crafted by human experts. Here, we propose automatic processes for learning useful domain-specific feature sets with little or no human intervention. Our methods select and add features that describe state-space regions of high inconsistency in the Bellman equation (statewise Bellman error) during approximate value iteration. Our method can be applied using any real-valued-feature hypothesis space and corresponding learning method for selecting features from training sets of state-value pairs. We evaluate the method with hypothesis spaces defined by both relational and propositional feature languages, using nine probabilistic planning domains. We show that approximate value iteration using a relational feature space performs at the state-of-the-art in domain-independent stochastic relational planning. Our method provides the first domain-independent approach that plays Tetris successfully (without human-engineered features).
Factors that affect the EVA encapsulant discoloration rate upon accelerated exposure

Several factors that affect the discoloration rate of the ethylene-vinyl acetate (EVA) copolymer encapsulants used in crystalline-Si photovoltaic (PV) modules upon accelerated exposure have been investigated primarily by employing UV-visible spectrophotometry, spectrocolorimetry, and fluorescence analysis. A variety of film samples including the two typical (unprimed) EVA formulations, A9918 and 15295, were studied. The films were laminated, cured, and exposed to either a concentrated 1-kW Xe or an enhanced-UV light source. The results indicate that the extent of EVA discoloration can be affected by factors of two general categories: chemical and physical. In the chemical category, the degradative factors include (1) EVA formulation, (2) presence and concentration of curing-generated, UV-excitable chromophores that depend on the type of curing agent used, (3) loss rate of the UV absorber, Cyasorb UV 531TM, (4) curing agent and curing conditions, and (5) photobleaching reactions due to diffusion of air into the laminated films. In the physical category, the factors involve (6) UV light intensity, (7) UV-filtering effect of glass superstrates, (8) gas permeability of polymeric superstrates, (9) film thickness, and (10) lamination-delamination (maybe chemical and/or mechanical effect, too). Photodecomposition of the Cyasorb was first verified in cyclohexane solutions and then in Elvax 150TM (EVX) films (the copolymer without any additives and curing agent). Cyasorb decomposition rates in cyclohexane solutions are exponentially proportional to the light intensity, but can be greatly reduced by a free-radical scavenger, Tinuvin 770TM, and furthermore by an antioxidant, Naugard PTM. The discoloration rate of EVA increases with increasing loss of Cyasorb UV 531 and is faster for the EVA A9918 films that have a greater concentration of UV-excitable chromophores generated from a slower curing than for the EVA 15295 films that are fast cured. In general, the loss rate of the UV absorber and the rate of discoloration from light yellow to brown follow a sigmoidal pattern. A reasonably good correlation for changes in transmittance at 420 nm, yellowness index, and fluorescence peak area (or intensity ratio) is obtained as the extent of EVA discoloration progresses. No discoloration was observed for the laminated EVX films that contain no stabilizers and curing-generated chromophores. The discoloration rate of both types of EVA can be largely reduced by UV-filtering glass superstrates that remove UV< 320nm. Photobleaching reactions are responsible for the non-discoloration of unlaminated EVA, the visually clear perimeter around the edges of laminated samples, and the EVA films laminated with gas-permeable polymer film superstrates. Delamination of EVA films from the top glass superstrate was observed after prolonged UV exposure.
“Top-Down” Effects Where None Should Be Found The El Greco Fallacy in Perception Research

A tidal wave of recent research purports to have discovered that higher-level states such as moods, action capabilities, and categorical knowledge can literally and directly affect how things look. Are these truly effects on perception, or might some instead reflect influences on judgment, memory, or response bias? Here, we exploited an infamous art-historical reasoning error (the so-called “El Greco fallacy”) to demonstrate that multiple alleged top-down effects (including effects of morality on lightness perception and effects of action capabilities on spatial perception) cannot truly be effects on perception. We suggest that this error may also contaminate several other varieties of top-down effects and that this discovery has implications for debates over the continuity (or lack thereof) of perception and cognition.
Chlorosulfonyl isocyanate reactions with N-(alkoxycarbonyl)-2-azabicyclo[2.2.0]hex-5-enes. Regiospecific two-atom insertion pathways.

Addition of the uniparticulate electrophile chlorosulfonyl isocyanate to the nitrogen atom of N-(alkoxycarbonyl)-2-azabicyclo[2.2.0]hex-5-enes 1 is followed by ring cleavage and recombination. The parent 4-methyl, 5-methyl, 5-bromo, and 5-phenyl azabicycles 1a−f afforded novel 2,4-diaza-3-oxo-bicyclo[4.2.0]oct-7-enes 10a−f. The 3-endo-phenyl azabicycle 1g rearranged to a 6-styryl-1,3-diaza-2-oxo-cyclohex-4-ene 12.
Evaluation of Left Atrial Volumes Using Multidetector Computed Tomography: Comparison with Echocardiography

Objective: To prospectively assess the relationship between the two different measurement methods for the evaluation of left atrial (LA) volume using cardiac multidetector computed tomography (MDCT) and to compare the results between cardiac MDCT and echocardiography. Materials and Methods: Thirty-five patients (20 men, 15 women; mean age, 60 years) underwent cardiac MDCT angiography for coronary artery disease. The LA volumes were measured using two different methods: the two dimensional (2D) length-based (LB) method measured along the three-orthogonal planes of the LA and the 3D volumetric threshold-based (VTB) method measured according to the threshold 3D segmentation of the LA. The results obtained by cardiac MDCT were compared with those obtained by echocardiography. Results: The LA end-systolic and end-diastolic volumes (LAESV and LAEDV) measured by the 2D-LB method correlated well with those measured by the 3DVTB method using cardiac MDCT (r = 0.763, r = 0.786, p = 0.001). However, there was a significant difference in the LAESVs between the two measurement methods using cardiac MDCT (p < 0.05). The LAESV measured by cardiac MDCT correlated well with measurements by echocardiography (r = 0.864, p = 0.001), however with a significant difference (p < 0.01) in their volumes. The cardiac MDCT overestimated the LAESV by 22% compared to measurements by echocardiography. Conclusion: A significant correlation was found between the two different measurement methods for evaluating LA volumes by cardiac MDCT. Further, cardiac MDCT correlates well with echocardiography in evaluating the LA volume. However, there are significant differences in the LAESV between the two measurement methods using cardiac MDCT and between cardiac MDCT and echocardiography.
Is there a Supermassive Black Hole at the Center of the Milky Way

This review outlines the observations that now provide an overwhelming scientific case that the center of the Milky Way harbors a supermassive black hole. Observations at infrared wavelength trace stars that orbit about a common focal position and require a central mass (M) of 4 × 106 M⊙ within a radius of 100 AU. Orbital speeds have been observed to exceed 5,000 km s-1. At the focal position there is an extremely compact radio source (Sgr A*), whose apparent size is near the Schwarzschild radius (2GM/c2). This radio source is motionless at the ~ 1 km s-1 level at the dynamical center of the Galaxy. The mass density required by these observations is now approaching the ultimate limit of a supermassive black hole within the last stable orbit for matter near the event horizon.
Synthetic approaches to an isostructural series of redox-active, metal tris(bipyridine) core dendrimers.

Several types of six-armed, metal tris(bipyridine) core dendrimers were synthesized. Bis-4,4‘-alkoxy bipyridine dendrons were prepared and employed to make tris(bipyridine) dendrimers. Although the ruthenium-centered and iron-centered dendrimers displayed quasi-reversible cyclic voltammetry, the analogous cobalt-centered complex did not. The synthesis of 4,4‘-disubstituted bipyridines containing −CH2OR groups proceeded in low yield. The reactions of the dicarbanion of 4,4‘-dimethyl bipyridine prepared with LDA and mesylate, triflate, and bromide groups were found to result in no or poor yields of carbon−carbon bond formation. Use of KDA in place of LDA resulted in much higher yields of dendritic bipyridines.
Probing the dark ages with metal absorption lines

Recent observations of high-redshift quasars at z∼ 6 have finally revealed complete Gunn–Peterson absorption. However, this at best constrains the volume-weighted and mass-weighted neutral fractions to be xVHI≥ 10−3 and xMHI≥ 10−2 respectively; stronger constraints are not possible because of the high optical depth for hydrogen Lyman transitions. Here I suggest certain metal lines as tracers of the hydrogen neutral fraction. These lines should cause unsaturated absorption when the intergalactic medium is almost fully neutral, if it is polluted to metallicities Z∼ 10−3.5–10−2.5 Z⊙. Such a minimal level of metal pollution is inevitable in the middle to late stages of reionization unless quasars rather than stars are the dominant source of ionizing photons. The O i line at 1302 A is particularly promising: the O i and H ionization potentials are almost identical, and O i should be in very tight charge exchange equilibrium with H. The Si ii 1260 A transition might also be observable. At high redshift, overdense regions are the first to be polluted to high metallicity but the last to remain permanently ionized, as a result of the short recombination times. Such regions should produce a fluctuating O i and Si ii forest, which, if observed, would indicate large quantities of neutral hydrogen. The O i forest may already be detectable in the Sloan Digital Sky Survey z= 6.28 quasar. If seen in future high-redshift quasars, the O i and Si ii forests will probe the topology of reionization and metal pollution in the early Universe. If, in addition, the H i optical depth can be measured from the damping wing of a high-redshift γ-ray burst, they will yield a very robust measure of the metallicity of the high-redshift Universe.
Mupirocin ointment with and without chlorhexidine baths in the eradication of Staphylococcus aureus nasal carriage in nursing home residents

Abstract Background: Mupirocin ointment has been shown to be effective in eradicating Staphylococcus aureus nasal carriage in residents of a long-term care facility. Antiseptic soaps have been used as adjunct to this therapy. We compared the efficacy of short-term intranasal mupirocin ointment with and without chlorhexidine baths in the eradication of S. aureus nasal carriage with follow-up for 12 weeks. Methods: Residents in four nursing homes known to have endemic methicillin-resistant S. aureus were screened for nasal carriage of S. aureus . Residents who had anterior nares cultures positive for S. aureus on two separate occasions were divided into two groups. Both groups received intranasal mupirocin ointment twice daily for 5 days and one group also received chlorhexidine baths for the first 3 days. Cultures of anterior nares, axilla, and groins were performed before treatment and 1 day and 1, 4, 8, and 12 weeks after treatment. Results: After treatment, S. aureus nasal carriage was eradicated in all residents. Recolonization with S. aureus had occurred at 12 weeks in 24% of residents receiving mupirocin ointment alone (625) and in 15% of residents receiving mupirocin ointment plus chlorhexidine baths (427). Conclusions: A short course of mupirocin ointment was effective in eradicating nasal carriage of S. aureus in nursing home residents. There were no statistical differences in efficacy between the two regimens with respect to the eradication of nasal carriage and prevention of recolonization with S. aureus.
More) Efficient Reinforcement Learning via Posterior Sampling

Most provably-efficient reinforcement learning algorithms introduce optimism about poorly-understood states and actions to encourage exploration. We study an alternative approach for efficient exploration: posterior sampling for reinforcement learning (PSRL). This algorithm proceeds in repeated episodes of known duration. At the start of each episode, PSRL updates a prior distribution over Markov decision processes and takes one sample from this posterior. PSRL then follows the policy that is optimal for this sample during the episode. The algorithm is conceptually simple, computationally efficient and allows an agent to encode prior knowledge in a natural way. We establish an O(τS/√AT) bound on expected regret, where T is time, τ is the episode length and S and A are the cardinalities of the state and action spaces. This bound is one of the first for an algorithm not based on optimism, and close to the state of the art for any reinforcement learning algorithm. We show through simulation that PSRL significantly outperforms existing algorithms with similar regret bounds.
Sojourners and Survivors: Two Logics of Constitutional Protection

Liberal political analysis is ordinarily based on a sharp distinction between domestic and international politics, and an assumption that domestic politics is the proper arena for democratic self-determination. But self-governing citizens have never exhausted the cast of characters who populate liberal states. Living alongside them there are often domestic aliens – permanent residents who are subject to the law, and may be protected by it, but who do not participate in making it. Refugees and remnants also inhabit liberal states. Whether citizens or not, they tend to bear the historical consciousness of victims or potential victims wherever they may live. A correlative fact is that in many now-liberal societies the meaning of citizenship itself is indelibly marked by the “missing” – the emigrant and the exile, the expelled and the extinct. Such identities – and the historical presence or absence of individuals who claim them – are generally regarded as messy details in the state-centered conceptual framework that dominates liberal political thought.
End-to-end continuous flow synthesis and purification of diphenhydramine hydrochloride featuring atom economy, in-line separation, and flow of molten ammonium salts

A continuous end-to-end synthesis and purification of diphenhydramine hydrochloride featuring atom economy and waste minimization is described. Combining a 1 : 1 molar ratio of the two starting material streams (chlorodiphenylmethane and N,N-dimethylaminoethanol) in the absence of additional solvent at high temperature gives the target compound directly as a molten salt (ionic liquid above 168 °C) in high yield. This represents the first example of continuous active pharmaceutical ingredient (API) production in this manner. Six of the twelve principles of green chemistry as defined by the American Chemical Society are achieved, most prominently waste minimization and atom economy.
BMS supertranslations and Weinberg’s soft graviton theorem

Recently it was conjectured that a certain infinite-dimensional “diagonal” subgroup of BMS supertranslations acting on past and future null infinity ( and ) is an exact symmetry of the quantum gravity S-matrix, and an associated Ward identity was derived. In this paper we show that this supertranslation Ward identity is precisely equivalent to Weinberg’s soft graviton theorem. Along the way we construct the canonical generators of supertranslations at , including the relevant soft graviton contributions. Boundary conditions at the past and future of and a correspondingly modified Dirac bracket are required. The soft gravitons enter as boundary modes and are manifestly the Goldstone bosons of spontaneously broken supertranslation invariance.
Quantitative small field-of-view pinhole SPECT imaging: initial evaluation

A quantitative filtered backprojection (FBP) algorithm for small field-of-view pinhole SPECT has been implemented and evaluated. This algorithm compensates for attenuation, scatter, geometric collimator response and system misalignment. Pinhole SPECT quantification with three different pinhole collimators was evaluated using experimentally acquired phantom data. SPECT scans using both in-air and in-water point sources located at different places and a cylinder filled with uniform activity were acquired. Planar scans of an in-air point source from different incident angles were acquired to determine the angular dependence of the geometric collimator response. Images were reconstructed using the FBP algorithm, with geometric response correction, dual-window scatter subtraction (c=0.4), single iteration Chang attenuation compensation, and system misalignment correction. Total activities in point source experiments and concentrations in cylindrical phantom experiments were measured. Accurate quantitative results ( >
Fourth- and higher-order small-perturbation solution for scattering from dielectric rough surfaces

A recursive solution of the small-perturbation method for rough surface scattering is presented. These results permit fourth- and higher-order corrections to rough surface scattering coefficients to be determined in a form that explicitly separates surface and electromagnetic properties. Sample results are presented for the fourth-order correction to the specular reflection coefficient of a rough surface and the sixth-order correction to incoherent scattering cross sections.
Dynamic Approaches to In-network Aggregation

Collaboration between small-scale wireless devices depends on their ability to infer aggregate properties of all nearby nodes. The highly dynamic environment created by mobile devices introduces a silent failure mode that is disruptive to this kind of inference. We address this problem by presenting techniques for extending existing unstructured aggregation protocols to cope with failure modes introduced by mobile environments. The modified protocols allow devices with limited connectivity to maintain estimates of aggregates, despite \textit{unexpected} peer departures and arrivals.
In-Line Forces on Vertical Cylinders in Deepwater Waves

Laboratory measurements of the total in-line forces on a fixed vertical 2-in-dia cylinder in deep-water regular and random waves are given and compared with predictions from the Morison equation. Results show, for regular waves with heights ranging from 2 to 22 in. and frequencies ranging from 0.4 to 0.9 Hz that the Morison equation, with Stokes wave theory and constant drag and inertia coefficients of 1.2 and 1.8, respectively, provides good agreement with the measured maximum wave forces. The force variation over the entire wave cycle is also well represented. The linearized Morison equation, with linear wave theory and the same coefficients likewise provides close agreement with the measured rms wave forces for irregular random waves having approximate Bretschneider spectra and significant wave heights from 5 to 14 in. The success of the constant-coefficient approximation is attributed to a decreased dependence of the coefficients on dimensionless flow parameters as a result of the circular particle motions and large kinematic gradients of the deep-water waves.
The spatial structure of networks

We study networks that connect points in geographic space, such as transportation networks and the Internet. We find that there are strong signatures in these networks of topography and use patterns, giving the networks shapes that are quite distinct from one another and from non-geographic networks. We offer an explanation of these differences in terms of the costs and benefits of transportation and communication, and give a simple model based on the Monte Carlo optimization of these costs and benefits that reproduces well the qualitative features of the networks studied.
The Effects of Protons on the Hydrogenolysis of Neopentane over Rhodium Catalysts: Rh/Hy, Rh/Nahy, and Rh/SiO2

Abstract The hydrogenolysis of neopentane (2,2-dimethylpropane) has been studied over the rhodium catalysts Rh/HY, Rh/NaHY, and Rh/SiO 2 . The catalytic activity follows the sequence: Rh/HY > Rh/NaHY ≈ Rh/SiO 2 . For all catalysts, the conversion of neopentane was 100% selective to hydrogenolysis products, methane, and isobutane; they are formed in a ratio of 1 : 1. In an attempt to determine the true activation energies from the apparent activation energies derived from the Arrhenius curves, corrections were made for the preequilibrium between gaseous and physisorbed neopentane. The adsorption of neopentane on the metal-free supports was determined: isosteric heats of adsorption were calculated from these data. For zeolites NaY and HY they are 8.2 and 7.0 kcal/mol, respectively. After correcting for the preequilibrium, the true activation energies are 33.5 and 38.8 kcal/mol for Rh/HY and Rh/NaHY, respectively. The results lend support to the concept that the superior activity of Rh/HY is due to the "electron deficiency" of the rhodium particles.
Society's Needs in Scientific and Technical Information

Processa-se, presentemente, uma segunda revolucao na transmissao da informacao cientifica, comparavel, talvez, ao advento do periodico cientifico. A rapidez de comunicacao na frente de pesquisa nao mais depende do sistema de comunicacao da literatura periodica, que permanece, no entanto, o principal veiculo para o registro do conhecimento cientifico. Um sistema moderno poderia incluir um periodico diario, para rapida disseminacao, e tambem um conjunto de periodicos baseado em uma colecao de documentos reestruturado em classes, de acordo com correlacao de citacoes. Desta forma, os processos de utilizacao, e validade seriam separados dos cie acumulacao do registro cientifico, em vez de combinados, como acontece no presente sistema. As tecnicas bibliometricas atuais tornam tal estrutura possivel. Abstract A second revolution in the transmission of scientific information, perhaps comparable to the advent of the scientific journal is presently underway. Rapid research front communication is no longer dependent upon the journal communication system which remains, however, the key record of the accumulation of scientific knowledge. A modern system might well include a daily newspaper format for high speed dissemination and a restructured set of journals based on the collection of papers into classes on the basis of their citation linkages. The processes of use and validation would thus be separated from that of the cumulation of scientific record, rather than combined as in the present system. Current bibliometric techniques make such a structure possible.
Development of a Multistage Reliability-Based Design Optimization Method

Abstract : Complex system acquisition and its associated technology development have a troubled recent history. The modern acquisition timeline consists of conceptual, preliminary, and detailed design followed by system test and production. The evolving nature of the estimates of system performance, cost, and schedule during this extended process may be a significant contribution to recent issues. The recently proposed multistage reliability based design optimization (MSRBDO) method promises improvements over reliability based design optimization (RBDO) in achieved objective function value. In addition, its problem formulation more closely resembles the evolutionary nature of epistemic design uncertainties inherent in system design during early system acquisition. Our goal is to establish the modeling basis necessary for applying this new method to the engineering of early conceptual/preliminary design. We present corrections in the derivation and solutions to the single numerical example problem published by the original authors, Nam and Mavris, and examine the error introduced under the reduced-order reliability sampling used in the original publication. MSRBDO improvements over the RBDO solution of 10-36% for the objective function after first-stage optimization are shown for the original second-stage example problem. A larger 26-40% improvement over the RBDO solution is shown when an alternative comparison method is used than in the original. The specific implications of extending the method to arbitrary m-stage problems are presented, together with a solution for a three-stage numerical example. Several approaches are demonstrated to mitigate the computational cost increase of MSRBDO over RBDO, resulting in a net decrease in calculation time of 94% from an initial MSRBDO baseline algorithm.
Toward a Theory of the Strong Interactions

A systematic study is made of the relevant degrees of freedom and the dynamics of quantum chromodynamics (QCD). We find that the dynamical properties of QCD are, to a large extent, a consequence of the structure of the vacuum arising from the tunneling between degenerate, classically stable, vacuums, and that the relevant degrees of freedom can be taken to be the Euclidean path histories that can be used to calculate the tunneling in the semiclassical approximation. This nonperturbative vacuum structure appears well suited to the major features of QCD, i.e., the dimensional transmutation that determines the size of the hadrons and the strong-interaction coupling constant, the source of dynamical chiral symmetry breaking, and the mechanism responsible for quark confinement.
Redistribution when avoidance behavior is heterogeneous

Abstract The optimal income taxation framework is extended to account for heterogeneity in avoidance behavior. The optimal tax formulae are shown to be simply and intuitively modified to reflect the value of taxable income as an indicator of the need for transfers at a given skill level. This effect is in addition to any effect implied by just considering additional margins of response to taxes. Alternative sources of heterogeneity and their likely consequences are discussed. When the choice of administration is added to the model, it is demonstrated that the optimal tax system may include some seemingly wasteful avoidance schemes, even if they could be eliminated without any cost. When an avoidance scheme is more heavily used by the needy, it may provide additional redistribution without affecting standard incentive constraints.
A dynamic local method for bandwidth adaptation in bundle links to conserve energy in core networks

Abstract In this paper, we propose two distributed local-optimized algorithms (FLHT and DLHT), which can dynamically adjust the number of active sublinks, to save power consumption in the core network for both bin packing and load-balancing cases. A series of experiments were conducted on an Internet2 based synthetic network for both cases. The experiment results show that our FLHT and DLHT algorithms can achieve high energy savings without substantial data loss.
The Spread of Obesity in a Large Social Network over 32 Years

Background The prevalence of obesity has increased substantially over the past 30 years. We performed a quantitative analysis of the nature and extent of the person-to-person spread of obesity as a possible factor contributing to the obesity epidemic. Methods We evaluated a densely interconnected social network of 12,067 people assessed repeatedly from 1971 to 2003 as part of the Framingham Heart Study. The bodymass index was available for all subjects. We used longitudinal statistical models to examine whether weight gain in one person was associated with weight gain in his or her friends, siblings, spouse, and neighbors. Results Discernible clusters of obese persons (body-mass index [the weight in kilograms divided by the square of the height in meters], ≥30) were present in the network at all time points, and the clusters extended to three degrees of separation. These clusters did not appear to be solely attributable to the selective formation of social ties among obese persons. A person’s chances of becoming obese increased by 57% (95% confidence interval [CI], 6 to 123) if he or she had a friend who became obese in a given interval. Among pairs of adult siblings, if one sibling became obese, the chance that the other would become obese increased by 40% (95% CI, 21 to 60). If one spouse became obese, the likelihood that the other spouse would become obese increased by 37% (95% CI, 7 to 73). These effects were not seen among neighbors in the immediate geographic location. Persons of the same sex had relatively greater influence on each other than those of the opposite sex. The spread of smoking cessation did not account for the spread of obesity in the network. Conclusions Network phenomena appear to be relevant to the biologic and behavioral trait of obesity, and obesity appears to spread through social ties. These findings have implications for clinical and public health interventions.
Endothelial barrier dysfunction in diabetic conduit arteries: a novel method to quantify filtration

The endothelial barrier plays an important role in atherosclerosis, hyperglycemia, and hypercholesterolemia. In the present study, an accurate, reproducible, and user-friendly method was used to fu...
Characteristics of physician relocation following Hurricane Katrina.

Introduction: On August 29, 2005, Hurricane Katrina made landfall along the US Gulf Coast, resulting in the evacuation of >1.5 million people, including nearly 6000 physicians. This article examines the relocation patterns of physicians following the storm, determines the impact that the disaster had on their lives and practices, and identifies lessons learned. Methods: An Internet-based survey was conducted among licensed physicians reporting addresses within Federal Emergency Management Agency–designated disaster zones in Louisiana and Mississippi. Descriptive data analysis was used to describe respondent characteristics. Multivariate logistic regression was performed to identify the factors associated with physician nonreturn to original practice. For those remaining relocated out of state, bivariate analysis with χ 2 or Fisher exact test was used to determine factors associated with plans to return to original practice. Results: A total of 312 eligible responses were collected. Among disaster zone respondents, 85.6% lived in Louisiana and 14.4% resided in Mississippi before the hurricane struck. By spring 2006, 75.6% (n = 236) of the respondents had returned to their original homes, whereas 24.4% (n = 76) remained displaced. Factors associated with nonreturn to original employment included family or general medicine practice (OR 0.42, 95% CI 0.17–1.04; P = .059) and severe or complete damage to the workplace (OR 0.24, 95% CI 0.13–0.42; P Conclusions: A sizeable proportion of physicians remain displaced after Hurricane Katrina, along with a lasting decrease in the number of physicians serving in the areas affected by the disaster. Programs designed to address identified physician needs in the aftermath of the storm may give confidence to displaced physicians to return. ( Disaster Med Public Health Preparedness . 2007;1:21–26)
Studies toward the synthesis of azadirachtin, part 2: construction of fully functionalized ABCD ring frameworks and unusual intramolecular reactions induced by close-proximity effects.

The remarkable antifeedant agent and insecticide, azadirachtin (1), has, to date, escaped a total synthesis. The preparation of an advanced precursor has revealed some of the inner intricacies of this uniquely crowded and highly functionalized molecular architecture.
Periplanone total synthesis via intramolecular pinacol coupling

Abstract We have carried out an enantioselective synthesis of (-)-periplanone C by a route involving titanium-induced, intramolecular pinacol coupling reaction of a 1,10 keto aldehyde as the key step. The coupling occurs with predictable stereochemistry to give a mixture of two diol products in greater than 60% yield.
Numerical modeling of impact-induced hydrothermal activity at the Chicxulub crater

Large impact events like the one that formed the Chicxulub crater deliver significant amounts of heat that subsequently drive hydrothermal activity. We report on numerical modeling of Chicxulub crater cooling with and without the presence of water. The model inputs are constrained by data from borehole samples and seismic, magnetic, and gravity surveys. Model results indicate that initial hydrothermal activity was concentrated beneath the annular trough as well as in the permeable breccias overlying the melt. As the system evolved, the melt gradually cooled and became permeable, shifting the bulk of the hydrothermal activity to the center of the crater. The temperatures and fluxes of fluid and vapor derived from the model are consistent with alteration patterns observed in the available borehole samples. The lifetime of the hydrothermal system ranges from 1.5 to 2.3 Myr depending on assumed permeability. The long lifetimes are due to conduction being the dominant mechanism of heat transport in most of the crater, and significant amounts of heat being delivered to the near-surface by hydrothermal upwellings. The long duration of the hydrothermal system at Chicxulub should have provided ample time for colonization by thermophiles and/or hyperthermophiles. Because habitable conditions should have persisted for longer time in the central regions of the crater than on the periphery, a search for prospective biomarkers is most likely to be fruitful in samples from that region.
New Synthetic Technology for the Rapid Construction of Novel Heterocycles—Part 1: The Reaction of Dess - Martin Periodinane with Anilides and Related Compounds**

The unusual behavior of hypervalent iodine reagents, Dess - Martin periodinane and IBX, with an array of anilides leads to the formation of complex heterocycles in only one synthetic operation (see scheme). Furthermore, the substrates for these transformations are available in one step from readily available commercial building blocks. The mechanism by which these periodinanes interact with anilides is also explored. This exciting new class of chemical reactions was discovered during the course of the total synthesis of the CP molecules and leads to compounds which are relevant to chemical biology investigations and pharmaceutical research.
Examining the education gradient in chronic illness

We examine the education gradient in diabetes, hypertension, and high cholesterol. We take into account diagnosed as well as undiagnosed cases, and use methods accounting for the possibility of unmeasured factors that are correlated with education and drive both the likelihood of having illness and the propensity to be diagnosed. Data come from the National Health and Nutrition Examination Survey (NHANES) 1999-2012. The education gradient in chronic disease varies by whether self-reported or objective disease measures are used. Education is negatively associated with having undiagnosed disease in some cases, but findings vary by how we define undiagnosed disease.
Why Does the Law of One Price Fail? An Experiment on Index Mutual Funds

We conduct an experiment to evaluate why individuals invest in high-fee index funds. In our experiments, subjects allocate $10,000 across four S&P 500 index funds and are rewarded for their portfolio's subsequent return. Subjects overwhelmingly fail to minimize fees. We can reject the hypothesis that subjects buy high-fee index funds because of bundled non-portfolio services. Search costs for fees matter, but even when we eliminate these costs, fees are not minimized. Instead, subjects place high weight on annualized returns since inception. Fees paid decrease with financial literacy. Interestingly, subjects who choose high-fee funds sense they are making a mistake.
Wrist arthrodesis using dorsal radial bone graft

A modification of the Gill technique of wrist arthrodesis using a local bone graft and a combination of Kirschner wires and a tension band wire is described. This technique was used in 17 patients for either limited or complete wrist fusion. Follow-up over an average period of 18.1 months in 16 patients showed union in all 16. Time to union averaged 2.36 months. In three patients, the tension band wire needed to be removed. The advantages of this technique are its simplicity, versatility, and reliability without the need for a distant bone graft.
Bounds on Elasticities With Optimization Frictions: A Synthesis of Micro and Macro Evidence on Labor Supply

How can price elasticities be identified when agents face optimization frictions such as adjustment costs or inattention? I derive bounds on structural price elasticities that are a function of the observed effect of a price change on demand, the size of the price change, and the degree of frictions. The degree of frictions is measured by the utility losses agents tolerate to deviate from the frictionless optimum. The bounds imply that frictions affect intensive margin elasticities much more than extensive margin elasticities. I apply these bounds to the literature on labor supply. The utility costs of ignoring the tax changes used to identify intensive margin labor supply elasticities are typically less than 1% of earnings. As a result, small frictions can explain the differences between micro and macro elasticities, extensive and intensive margin elasticities, and other disparate findings. Pooling estimates from existing studies, I estimate a Hicksian labor supply elasticity of 0.33 on the intensive margin and 0.25 on the extensive margin after accounting for frictions.
Breaking of Nanotube Symmetry by Substrate Polarization

Substrate and nanotube polarization are shown to qualitatively change a nanotube bandstructure. The effect is studied in a linear approximation in an external potential which causes the changes. A work function difference between the nanotube and gold surface is estimated to be large enough to break the band symmetry and lift a degeneracy of a lowest but one subband of a metallic nanotube. This subband splitting for a [10,10] nanotube is about 50 meV in absence of other external potential.
Adoption of Electronic Technologies in Local U.S. Governments: Distinguishing Between E-Services and Communication Technologies

Local governments in the United States have adopted and implemented e-government as a means of delivering services to the public and encouraging citizen participation. We use data from a national r...
Sustainable Approaches to Managing Small-Scale Ecosystems: A Case Study of Vernal Pool Protection in the Commonwealth of Massachusetts, United States of America

This paper reviews the current management scheme used by Massachusetts to protect vernal pools, which represent small-scale ecosystems, and analyzes the scheme’s relative strengths and weaknesses from an overall sustainability standpoint by looking at the frameworks developed for management. The frameworks are analyzed to determine if the objectives of vernal pool protection are being met. The initial impression is the outcomes are not meeting the objective of overall vernal pool protection, because there are failures in the drivers (mainly the certification requirement), which limits the number of vernal pools actually protected. An expansion of the current Massachusetts program is suggested to allow for proper consideration of all vernal pool resources regardless of their physical location, proximity to priority habitat, or their legal status at the time of review. Such an expansion would allow for the quantifiable ecosystem services provided by vernal pools to be more readily protected. However, such an expansion also raises important legal questions regarding the extent to which private property can be regulated in the United States. Although this question is not analyzed within the context of this paper, it may limit the application of certain proposed solutions.
Calculation of transient thermal stresses in solid rocket propellants

Dirling, R., "A Method for Computing Roughwall Heat Transfer Rates on Reentry Nosetips," AIAA Paper 73-763, Palm Springs, Calif., 1973. Schlichting, H., Boundary Layer Theory (translated by J. Kestin), 4th ed., McGraw-Hill, New York, 1960, p. 320. Cansdale, J. and McNaughton, I., "Calculation of Surface Temperature and the Accretion Rate in a Mixed Water Droplet/Ice Crystal Cloud," Royal Aircraft Establishment Technical Report 77090,1977.
Performance technology for complex parallel and distributed systems

The ability of performance technology to keep pace with the growing complexity of parallel and distributed systems will depend on robust performance frameworks that can at once provide system-specific performance capabilities and support high-level performance problem solving. The TAU system is offered as an example framework that meets these requirements. With a flexible, modular instrumentation and measurement system, and an open performance data and analysis environment, TAU can target a range of complex performance scenarios. Examples are given showing the diversity of TAU application.
Nahm transform for periodic monopoles and N = 2 super Yang-Mills theory

We study Bogomolny equations on R^2×S^1. Although they do not admit nontrivial finite-energy solutions, we show that there are interesting infinite-energy solutions with Higgs field growing logarithmically at infinity. We call these solutions periodic monopoles. Using the Nahm transform, we show that periodic monopoles are in one-to-one correspondence with solutions of Hitchin equations on a cylinder with Higgs field growing exponentially at infinity. The moduli spaces of periodic monopoles belong to a novel class of hyperkahler manifolds and have applications to quantum gauge theory and string theory. For example, we show that the moduli space of k periodic monopoles provides the exact solution of N=2 super Yang–Mills theory with gauge group SU(k) compactified on a circle of arbitrary radius.
Trading Complex Assets

We perform an experimental study of complexity to assess its eect on trading behavior, price volatility, liquidity, and trade eciency. Subjects were asked to deduce the value of a particular asset from information they were given about the composition and price of several portfolios. Following that, subjects traded with each other anonymously in a well-dened, simple bargaining process. Portfolio composition ranged from requiring simple analysis to more complicated computation in order to deduce the value of the asset. Complexity altered subjects’ bidding strategies, decreased liquidity, increased price volatility, and decreased trade eciency. However, in follow-up experiments, we show that uncertainty over private values does not lead to the same changes in trading behavior. Therefore, while complexity induces estimation errors and higher uncertainty, this is not what drives our results.
Structure and vertical modes in finite 2D plasma crystals

The formation of finite 2D plasma crystals was numerically simulated to allow the investigation of structural symmetries for systems with various Debye lengths. For the case of increasing Debye length, a transition was discovered between a fully hexagonal structure and a structure having concentric rings along the outer edge and a hexagonal lattice in the interior. Additionally, the vertical as well as horizontal oscillation modes in a thermally excited two-dimensional (2D) dust coulomb cluster were investigated. The horizontal mode spectra is shown to agree with published results while the vertical mode spectra obtained from numerical simulation is shown to agree with current data from analytical methods. The vertical mode frequencies are shown to have a maximum corresponding to when the system acts as a solid plane. For low frequency modes, the largest amplitude particle motion is concentrated within a few inner rings with the outer rings remaining almost motionless. This provides an interesting contrast to the horizontal mode frequencies for which the strongest motion of the particles is concentrated within the inner rings at high frequencies.
The Great Recession and Its Aftermath: What Role for Structural Changes?

The years since the 2009 end of the Great Recession have been disastrous for many workers, particularly those with low human capital or other disadvantages. One explanation attributes this to deficient aggregate labor demand, to which marginal workers are more sensitive. A second attributes it to structural changes. Cyclical explanations imply that if aggregate labor demand is increased then many of the post-2009 patterns will revert to their pre-recession trends. Structural explanations suggest recent experience is the “new normal.” This paper reviews data since 2007 for evidence. I examine wage trends to measure the relative importance of supply and demand. I find little wage pressure before 2015, pointing to demand as the binding constraint. The most recent data show some signs of tightness, but still substantial slack.
Covenants without Swords Group Identity, Norms, and Communication in Social Dilemmas

In one-shot social dilemma experiments, cooperation rates dramatically increase if subjects are allowed to communicate before making a choice. There are two possible explanations for this `communic...