cssi/SciSciGPT-SciSciNet huggingface dataset:
The Power Curse: The Paradox of Power in World Politics

While the augmentation of power carries obvious benefits for nations, the very process itself possesses inherent qualities that can weaken a nation. Hence, power can be as much of a curse as a blessing because of these weakening effects. To the extent that national leaders do not correct for these effects, they are destined to become victims of a power illusion – i.e., that in reality their nations will become weaker and more vulnerable then they perceive.
A SYNOPSIS OF THE SOUTH AMERICAN LEPIDIUM (BRASSICACEAE)

Al-Shehbaz, I. A. 2010. A synopsis of the South American Lepidium (Brassicaceae). Darwiniana 48(2): 141-167. Fifty native and 12 naturalized species of Lepidium grow in South America, and a key to all 62 spe- cies is presented. Three new species from Argentina (L. hickenii, L. pedersenii, and L. santacruzensis) and two from Peru (L. cuzcoensis and L. werffii) are described, illustrated, and their relationships to nearest relatives are discussed. The new combination Lepidium crassius is proposed. Furthermore, 19 taxa (Coronopus didymus var. macrocarpus, C. didymus var. procumbens, L. abrotanifolium var. stein- mannii, L. affine, L. argentinum, L. auriculatum, L. bonariense var. pseudovirginicum, L. calycinum var. integrifolium, L. costaricense, L. cumingianum var. orbiculatum, L. cumingianum subsp. bertero- anum, L. depressum, L. myrianthum, L. neglectum, L. parodii, L. pubescens var. fallax, L. subvagina- tum, L. virginicum subsp. centrali-americanum, Thlaspi campestre) are lectotypified and 17 others (Coronopus leptocarpus, C. leptocarpus var. microcarpus, L. boelckii, L. bonariense var. gayi, L. bonariense var. pseudovirginicum, L. brevicaule, L. calycinum, L. danielsii, L. demissum, L. kalenbor- nii, L. morrisonii, L. peruvianum, L. philippianum var. boliviense, L. raimondii, L. scabrifructum, L. spicatum var. caylx-persistente, L. subvaginatum) are reduced to synonymy. L. depressum and L. rah- meri are new records for Argentina. Cincuenta especies nativas y 12 naturalizadas de Lepidium crecen en America del Sur, se presenta una clave para las 62 especies. Se describen e ilustran tres nuevas especies de Argentina (L. hickenii, L. pedersenii y L. santacruzensis) y dos para Peru (L. cuzcoensis y L. werffii), y se discuten sus rela- ciones con sus especies mas afines. Se propone Lepidium crassius comb. nov., se designa lectotipo para 19 binomios (Coronopus didymus var. macrocarpus, C. didymus var. procumbens, L. abrotanifo- lium var. steinmannii, L. affine, L. argentinum, L. auriculatum, L. bonariense var. pseudovirginicum, L. calycinum var. integrifolium, L. costaricense, L. cumingianum var. orbiculatum, L. cumingianum subsp. berteroanum, L. depressum, L. myrianthum, L. neglectum, L. parodii, L. pubescens var. fallax, L. subvaginatum, L. virginicum subsp. centrali-americanum, Thlaspi campestre), y se reducen a sino- nimos otros 17 nombres (Coronopus leptocarpus, C. leptocarpus var. microcarpus, L. boelckii, L. bonariense var. gayi, L. bonariense var. pseudovirginicum, L. brevicaule, L. calycinum, L. danielsii, L. demissum, L. kalenbornii, L. morrisonii, L. peruvianum, L. philippianum var. boliviense, L. raimondii, L. scabrifructum, L. spicatum var. caylx-persistente, L. subvaginatum). L. depressum y L. rahmeri son nuevos registros para la Argentina.
On uniform capacitated k-median beyond the natural LP relaxation

In this paper, we study the uniform capacitated k-median problem. In the problem, we are given a set F of potential facility locations, a set C of clients, a metric d over F ∪ C, an upper bound k on the number of facilities we can open and an upper bound u on the number of clients each facility can serve. We need to open a subset S ⊆ F of k facilities and connect clients in C to facilities in S so that each facility is connected by at most u clients. The goal is to minimize the total connection cost over all clients. Obtaining a constant approximation algorithm for this problem is a notorious open problem; most previous works gave constant approximations by either violating the capacity constraints or the cardinality constraint. Notably, all these algorithms are based on the natural LP-relaxation for the problem. The LP-relaxation has unbounded integrality gap, even when we are allowed to violate the capacity constraints or the cardinality constraint by a factor of 2 − e.Our result is an exp(O(1/e2))-approximation algorithm for the problem that violates the cardinality constraint by a factor of 1 + e. That is, we find a solution that opens at most (1 + e)k facilities whose cost is at most exp(O(1/e2)) times the optimum solution when at most k facilities can be open. This is already beyond the capability of the natural LP relaxation, as it has unbounded integrality gap even if we are allowed to open (2 − e)k facilities. Indeed, our result is based on a novel LP for this problem. We hope that this LP is the first step towards a constant approximation for capacitated k-median.The version as we described is the hard-capacitated version of the problem, as we can only open one facility at each location. This is as opposed to the soft-capacitated version, in which we are allowed to open more than one facilities at each location. The hard-capacitated version is more general, since one can convert a soft-capacitated instance to a hard-capacitated instance by making enough copies of each facility location. We give a simple proof that in the uniform capacitated case, the soft-capacitated version and the hard-capacitated version are actually equivalent, up to a small constant loss in the approximation ratio. Moreover, we show that the given potential facility locations do not matter: we can assume F = C.
High-brightness injectors for hadron colliders

The counterrotating beams in collider rings consist of trains of beam bunches with N{sub B} particles per bunch, spaced a distance S{sub B} apart. When the bunches collide, the interaction rate is determined by the luminosity, which is defined as the interaction rate per unit cross section. For head-on collisions between cylindrical Gaussian beams moving at speed {beta}c, the luminosity is given by L = N{sub B}{sup 2}{beta}c/4{pi}{sigma}{sup 2}S{sub B}, where {sigma} is the rms beam size projected onto a transverse plane (the two transverse planes are assumed identical) at the interaction point. This beam size depends on the rms emittance of the beam and the focusing strength, which is a measure of the 2-D phase-space area in each transverse plane, and is defined in terms of the second moments of the beam distribution. Our convention is to use the rms normalized emittance, without factors of 4 or 6 that are sometimes used. The quantity {tilde {beta}} is the Courant-Synder betatron amplitude function at the interaction point, a characteristic of the focusing lattice and {gamma} is the relativistic Lorentz factor. Achieving high luminosity at a given energy, and at practical values of {tilde {beta}} and S{sub B}, requires a large more » value for the ratio N{sub B}{sup 2}/{var epsilon}{sub n}, which implies high intensity and small emittance. Thus, specification of the luminosity sets the requirements for beam intensity and emittance, and establishes the requirements on the performance of the injector to the collider ring. In general, for fixed N{sub B}, the luminosity can be increased if {var epsilon}{sub n} can be reduced. The minimum emittance of the collider is limited by the performance of the injector; consequently the design of the injector is of great importance for the ultimate performance of the collider. « less
bhlight: GENERAL RELATIVISTIC RADIATION MAGNETOHYDRODYNAMICS WITH MONTE CARLO TRANSPORT

We present bhlight, a numerical scheme for solving the equations of general relativistic radiation magnetohydrodynamics using a direct Monte Carlo solution of the frequency-dependent radiative transport equation. bhlight is designed to evolve black hole accretion flows at intermediate accretion rate, in the regime between the classical radiatively efficient disk and the radiatively inefficient accretion flow (RIAF), in which global radiative effects play a sub-dominant but non-negligible role in disk dynamics. We describe the governing equations, numerical method, idiosyncrasies of our implementation, and a suite of test and convergence results. We also describe example applications to radiative Bondi accretion and to a slowly accreting Kerr black hole in axisymmetry.
Preparing topological states of a Bose-Einstein condensate

Observations of Bose–Einstein condensates—macroscopic populations of ultracold atoms occupying a single quantum state—in dilute alkali-metal and hydrogen gases have stimulated a great deal of research into the statistical physics of weakly interacting quantum degenerate systems1,2. Recent experiments offer a means of exploring fundamental low-temperature physics in a controllable manner. A current experimental goal in the study of trapped Bose gases is the observation of superfluid-like behaviour, analogous to the persistent currents seen in superfluid liquid helium which flow without observable viscosity. The ‘super’ properties of Bose-condensed systems occur because the macroscopic occupation of a quantized mode provides a stabilizing mechanism that inhibits decay through thermal relaxation3. Here we show how to selectively generate superfluid vortex modes with different angular momenta in a Bose–Einstein condensate. Our approach involves solving the time-dependent equation of motion of a two-component condensate with strongly coupled internal atomic states, as recently investigated experimentally4,5. The generation of vortices relies on the coupling between the states (achieved by applying an electromagnetic field), combined with mechanical rotation of the trapping potentials which confine the condensate.
Rate of Growth or Shrinkage of Nonequilibrium Ice Sheets

An analysis is made of the time required to build up an ice-age ice sheet and of the time required to destroy such an ice sheet. The calculations are based on the approximation that the theory of perfect plasticity is valid. It is concluded that the time required to build up an ice-age ice sheet is longer than the time required to eliminate it. If it is assumed that the accumulation rate of an ice-age ice sheet lies in the range of 0.2 to 0.6 m./yr., it is found that the growth time of a large ice sheet is of the order of 15,000 to 30,000 yr. Ablation rates of to 2 m./yr. lead to shrinkage times of the order of 2,000 to 4,000 yr., provided ablation occurs over an appreciable area of the ice sheet.
Adaptive robust optimization with dynamic uncertainty sets for multi-period economic dispatch under significant wind

The exceptional benefits of wind power as an environmentally responsible renewable energy resource have led to an increasing penetration of wind energy in today's power systems. This trend has started to reshape the paradigms of power system operations, as dealing with uncertainty caused by the highly intermittent and uncertain wind power becomes a significant issue. Motivated by this, we present a new framework using adaptive robust optimization for the economic dispatch of power systems with high level of wind penetration. In particular, we propose an adaptive robust optimization model for multi-period economic dispatch, and introduce the concept of dynamic uncertainty sets and methods to construct such sets to model temporal and spatial correlations of uncertainty. We also develop a simulation platform which combines the proposed robust economic dispatch model with statistical prediction tools in a rolling horizon framework. We have conducted extensive computational experiments on this platform using real wind data. The results are promising and demonstrate the benefits of our approach in terms of cost and reliability over existing robust optimization models as well as recent look-ahead dispatch models.
The indirect cost of natural disasters and an economic definition of macroeconomic resilience

The welfare impact of a disaster does not depend only on the physical characteristics of the event or its direct impacts in terms of lost lives and assets. Depending on the ability of the economy to cope, recover, and reconstruct, the reconstruction will be more or less difficult, and the welfare effects smaller or larger. This ability, which can be referred to as the macroeconomic resilience of the economy to natural disasters, is an important parameter to estimate the overall vulnerability of a population. Here, resilience is decomposed into two components: instantaneous resilience, which is the ability to limit the magnitude of the immediate loss of income for a given amount of capital losses, and dynamic resilience, which is the ability to reconstruct and recover quickly. The paper proposes a rule of thumb to estimate macroeconomic resilience, based on the interest rate (a higher interest rate decreases resilience and increases welfare losses), the reconstruction duration (a longer reconstruction duration increases welfare losses), and a “ripple-effect” factor that increases or decreases immediate losses (negative if enough idle resources are available to cope; positive if cross-sector and supply-chain issues impair the production of non-affected capital). An optimal risk management strategy is very likely to include measures to reduce direct impacts (disaster risk reduction actions) and measures to reduce indirect impacts (resilience building actions).
Determinants of farm income

Purpose – The recent fluctuations in farm income remind us of the boom-bust nature of the agricultural sector. To better understand these fluctuations in farm income, the purpose of this paper is to examine the relationship between farm income and influential factors from 1964 to 2010 allowing for structural breaks in the data. Design/methodology/approach – The authors estimate error-correction models for an overarching model and several sub-models at different scales based on their relationship with farm income: micro, meso, and macro. The authors then provide a series of impulse response functions (IRFs) that combine short- and long-run impacts in a rigorous framework indicating the response of farm income to shocks from any of the explanatory variables. Findings – Results indicate that prices paid (PP) and received by farmers, technological change, interest and exchange rates (ERs), gross domestic product (GDP) and land prices all influence farm income. Results using IRFs show how increases in farm inc...
Cellular, Molecular, and Metabolic Basis of Muscle Fatigue

The sections in this article are: 1 Definition and Current Theories of Fatigue 2 Muscle Fiber-Type Composition 3 Mechanical Properties 3.1 The Isometric Contractile Properties 3.2 The Maximal Shortening Speed and Peak Power 3.3 The Force-Frequency Relationship 4 Excitation-Contraction Coupling 4.1 Sarcolemma and T-Tubular Membranes 4.2 T-Tubular–Sarcoplasmic Reticulum Junction and Calcium Release 5 Lactic Acid, Intracellular pH And Fatigue 5.1 Muscle Lactate 5.2 Hydrogen Ion and Muscle Fatigue 6 Inorganic Phosphate and Muscle Fatigue 6.1 Total Phosphate and the Diprotonated Form 6.2 Mechanisms of Phosphate Action 7 High-Energy Phosphates and the Free Energy of ATP Hydrolysis 7.1 ATP and Muscle Fatigue 8 Blood Glucose and Muscle Glycogen 8.1 Hypoglycemia and Performance 8.2 Carbohydrate Metabolism and Muscle Fatigue 9 Ultrastructural Changes and Muscle Fatigue 9.1 Muscle Damage and Exercise Intensity 9.2 Organelle Susceptibility to Damage 10 Summary and Conclusions
COMBINING REVEALED AND STATED PREFERENCE DATA TO ESTIMATE THE NONMARKET VALUE OF ECOLOGICAL SERVICES: AN ASSESSMENT OF THE STATE OF THE SCIENCE

This paper reviews the marketing, transportation and environmental economics literature on the joint estimation of revealed preference (RP) and stated preference (SP) data. The RP and SP approaches are first described with a focus on the strengths and weaknesses of each. Recognizing these strengths and weaknesses, the potential gains from combining data are described. A classification system for combined data that emphasizes the type of data combination and the econometric models used is proposed. A methodological review of the literature is pursued based on this classification system. Examples from the environmental economics literature are highlighted. A discussion of the advantages and disadvantages of each type of jointly estimated model is then presented. Suggestions for future research, in particular opportunities for application of these models to environmental quality valuation, are presented.
Household investment under violence - the Colombian case

Households in rural Colombia are confronted with a variety of violent threats: attacks and displacement threats by guerrillas and paramilitaries, gang violence among drug traffickers, and high common delinquency. In this context, households have to adjust their day-to-day decisions, including saving and portfolio choices, in order to be less vulnerable. The authors test the hypothesis that households, when confronted with exogenous violence, reduce their investment and, moreover, shift it from fixed to mobile assets, which would be safer in the case of displacement, and choose the opposite strategy under higher common delinquency associated with property crimes. Empirical evidence from a rich Colombian micro-data set strongly supports the hypothesis. The results shed new light on the economic impact of violence. The immediate reduction in capital stock might be much less severe than more permanent damage via the savings function. This has implications for the appropriate political answer to chronic violence in Colombia as well as in other areas of chronic conflict.
Reporting location and the value relevance of accounting information: The case of other comprehensive income

ABSTRACT This paper examines the influence of reporting location on the value relevance of other comprehensive income (OCI). Accounting Standards Update (ASU) 2011-05 “Presentation of Comprehensive Income” requires firms to report OCI in a performance statement (i.e., either below net income in a single statement of comprehensive income or in a second statement of comprehensive income that begins with net income). ASU 2011-05 eliminated the option of reporting OCI in the statement of equity, based on the argument that performance reporting would improve the transparency of OCI in the financial statements. We find mixed evidence that the value relevance of OCI differs across management's choices of OCI reporting location prior to the implementation of ASU 2011-05. However, we do find a decline in the value relevance of OCI for firms that were required to change the reporting location of OCI from the statement of equity to a performance statement in response to ASU 2011-05. This result holds after we include a control group consisting of firms that did not change the reporting location of OCI. Overall, our findings suggest that the value relevance of OCI is determined by whether its reporting location is consistent with the firm's reporting history.
Prospects for Monetary Cooperation and Integration in East Asia

East Asian countries were notably uninterested in regional monetary integration until the late 1990s, when the Asian financial crisis revealed the fragility of the region's exchange rate arrangements and highlighted the need for a stronger regional financial architecture. Since then, the countries of East Asia have begun taking steps to explore monetary and financial cooperation, establishing such initiatives as regular consultations among finance ministers and central bank governors and the pooling of foreign exchange reserves. In this book, Ulrich Volz investigates the prospects for monetary cooperation and integration in East Asia, using state-of-the-art theoretical and empirical tools to analyze the most promising policy options. Volz points out that monetary cooperation can be defined broadly to include options ranging from informal policy consultations to European-style monetary union. He recommends a gradual approach toward monetary integration in East Asia, one that pursues less extensive forms of monetary cooperation before tackling such highly challenging projects as a regional exchange rate system or a regional monetary union. The simpler, less demanding forms of policy coordination would, Volz argues, allow East Asian countries to develop an integrationist spirit and gain experience in cooperation. Monetary integration is not an end in itself, Volz reminds us, but a means to promote economic and financial development and create a stable macroeconomic environment that is conducive to investment and growth. After providing an in-depth analysis of the costs and benefits of monetary integration, Volz examines different options for East Asian countries. He then proposes a strategy whereby countries first opt for a managed float of exchange rates guided by a regional currency basket into which an "Asian currency unit" is introduced as a virtual parallel currency to circulate alongside national currencies.
Growth implosions, debt explosions, and my Aunt Marilyn : do growth slowdowns cause public debt crises?

The worldwide slowdown in growth after 1975 was a major negative fiscal shock. Slower growth lowers the present value of tax revenues and primary surpluses and thus makes a given level of debt more burdensome. Most countries failed to adjust to the negative fiscal consequences of the growth implosion, so public-debt-to-GDP ratios exploded. The growth slowdown therefore played an important role in the debt crisis of the middle-income countries in the 1980s, the crisis of the heavily indebted poor countries (HIPCs) in the 1980s and 1990s, and the increased public debt burden of the industrial countries in the 1980s and 1990s. Moreover, the HIPCs' debt problems were worse than elsewhere because, as a result of poor policies, these countries grew more slowly after 1975 than other low-income countries. Econometric tests and fiscal solvency accounting confirm the important role of growth in debt crises.
Dynamical Properties of Timed Automata

Timed automata are an important model for specifying and analyzing real-time systems. The main analysis performed on timed automata is the reachability analysis. In this paper we show that the standard approach for performing reachability analysis is not correct when the clocks drift even by a very small amount. Our formulation of the reachability problem for timed automata is as follows: we define the set R^*(T,Z_0)=\cap_{\eps>0}\reach(T_\eps,Z_0) where T_\eps is obtained from timed automaton T by allowing an \eps drift in the clocks. R^*(T,Z_0) is the set of states which can be reached in the timed automatonT from the initial states in Z_0 when the clocks drift by an infinitesimally small amount. We present an algorithm for computing R^*(T,Z_0) and provide a proof of its correctness. We show that R^*(T,Z_0) is robust with respect to various types of modeling errors. To prove the correctness of our algorithm, we need to understand the dynamics of timed automata—in particular, the structure of the limit cycles of timed automata.
Aberration corrected emittance exchange

Full exploitation of emittance exchange (EEX) requires aberration-free performance of a complex imaging system including active radio-frequency (rf) elements which can add temporal distortions. We investigate the performance of an EEX line where the exchange occurs between two dimensions with normalized emittances which differ by multiple orders of magnitude. The transverse emittance is exchanged into the longitudinal dimension using a double dogleg emittance exchange setup with a five cell rf deflector cavity. Aberration correction is performed on the four most dominant aberrations. These include temporal aberrations that are corrected with higher order magnetic optical elements located where longitudinal and transverse emittance are coupled. We demonstrate aberration-free performance of an EEX line with emittances differing by four orders of magnitude, i.e., an initial transverse emittance of 1 pm-rad is exchanged with a longitudinal emittance of 10 nm-rad.
On the Equivalence Between Two Problems of Asymmetry on Convex Bodies

The simplex was conjectured to be the extremal convex body for the two following "problems of asymmetry": (P1) What is the minimal possible value of the quantity $$\max _{K'} |K'|/|K|$$maxK?|K?|/|K|? Here, $$K'$$K? ranges over all symmetric convex bodies contained in K. (P2) What is the maximal possible volume of the Blaschke body of a convex body of volume 1? Our main result states that (P1) and (P2) admit precisely the same solutions. This complements a result from Boroczky et al. (Discrete Math 69:101---120, 1986), stating that if the simplex solves (P1), then the simplex solves (P2) as well.
Don't just listen, use your imagination: Leveraging visual common sense for non-visual tasks

Artificial agents today can answer factual questions. But they fall short on questions that require common sense reasoning. Perhaps this is because most existing common sense databases rely on text to learn and represent knowledge. But much of common sense knowledge is unwritten - partly because it tends not to be interesting enough to talk about, and partly because some common sense is unnatural to articulate in text. While unwritten, it is not unseen. In this paper we leverage semantic common sense knowledge learned from images - i.e. visual common sense - in two textual tasks: fill-in-the-blank and visual paraphrasing. We propose to “imagine” the scene behind the text, and leverage visual cues from the “imagined” scenes in addition to textual cues while answering these questions. We imagine the scenes as a visual ab]ion. Our approach outperforms a strong text-only baseline on these tasks. Our proposed tasks can serve as benchmarks to quantitatively evaluate progress in solving tasks that go “beyond recognition”. Our code and datasets are publicly available.
Quadratic partial eigenvalue assignment in large-scale stochastic dynamic systems for resilient and economic design

Abstract Failure of structural systems under dynamic loading can be prevented via active vibration control which shifts the damped natural frequencies of the systems away from the dominant range of a loading spectrum. The damped natural frequencies and the dynamic load typically show significant variations in practice. A computationally efficient methodology based on quadratic partial eigenvalue assignment technique and optimization under uncertainty has been formulated in the present work that will rigorously account for these variations and result in economic and resilient design of structures. A novel scheme based on hierarchical clustering and importance sampling is also developed in this work for accurate and efficient estimation of probability of failure to guarantee the desired resilience level of the designed system. Finally the most robust set of feedback matrices is selected from the set of probabilistically characterized optimal closed-loop system to implement the new methodology for design of active controlled structures. Numerical examples are presented to illustrate the proposed methodology.
"Finding the Tipping Point -- When Sovereign Debt Turns Bad"

Public debt has surged during the current global economic crisis and is expected to increase further. This development has raised concerns whether public debt is starting to hit levels where it might negatively affect economic growth. Does such a tipping point in public debt exist? How severe would the impact of public debt be on growth beyond this threshold? What happens if debt stays above this threshold for an extended period of time? The present study addresses these questions with the help of threshold estimations based on a yearly dataset of 99 developing and developed economies spanning a time period from 1980 to 2008. The estimations establish a threshold of 77 percent public debt‐to‐GDP ratio. If debt is above this threshold, each additional percentage point of debt costs 0.017 percentage points of annual real growth. The effect is even more pronounced in emerging markets where the threshold is 64 percent debt‐to‐GDP ratio. In these countries, the loss in annual real growth with each additional percentage point in public debt amounts to 0.02 percentage points. The cumulative effect on real GDP could be substantial. Importantly, the estimations control for other variables that might impact growth, such as the initial level of per‐capita‐GDP.
Fabrication of Feedhorn-Coupled Transition Edge Sensor Arrays for Measurement of the Cosmic Microwave Background Polarization

Characterization of the minute cosmic microwave background (CMB) polarization signature requires multi-frequency high-throughput precision instrument systems. We have previously described the detector fabrication of a 40 gigahertz focal plane and now describe the fabrication of a 37-element dual-polarization detector module for measurement of the CMB at 90 gigahertz. The 72-TES (Transition Edge Sensor)-based bolometers in each module are coupled to a niobium-based planar orthomode transducer with integrated band defining filters implemented in microstrip transmission line. A single crystal silicon dielectric substrate serves as microstrip dielectric and as a thermal link between the membrane isolated MoAu TES operating at 150 millikelvins and the heat bath. A short silicon leg between the heat bath and the TES bolometer is designed for ballistic phonon transport and provides improved process control and uniformity of thermal conductance in the presence of phonon scattering on roughened surfaces. Micro-machined structures are used to realize the orthomode transducer backshort, provide out of band signal rejection, and a silicon photonic choke for feedhorn coupling are described. The backshort, choke wafer, and detector wafer are indium bump-bonded to create a single 37-element dual-polarization detector module. Fourteen such hexagonally shaped modules each 80 millimeters in size comprise two focal planes. These, along with the recently delivered 40 gigahertz focal plane, will survey a large fraction of the sky as part of the Johns Hopkins University-led ground-based CLASS (Cosmology Large Angular Scale Surveyor) telescope.
Two Degree-of-Freedom Parallel Mechanisms for High Bandwidth Vibration Suppression and Tracking

Limited degree-of-freedom (DOF) parallel kinematic mechanisms (PKM) are capable of high bandwidth tracking and disturbance rejection with smaller actuators than are required for serial machines. A high performance Nyquist-stable (NS) controller with nonlinear dynamic compensation (NDC) applied to a new PKM is presented. The Popov criterion is used to show absolute stability (AS) of the closed loop system and experimental evidence of closed loop performance is provided. This novel approach to PKM control provides 38 dB of disturbance rejection below 10 Hz, an order of magnitude more that what is achieved by implementing an absolutely stable fixed gain (ASFG) controller.
Optimal lateral guidance for low L/D shuttle vehicle entry.

Optimal lateral guidance switching thresholds for low L/D shuttle vehicle entry, using optimal stochastic control theory for problem formulation in conjunction with dynamic programming
Models of Galaxy Clusters with Thermal Conduction

We present a simple model of hot gas in galaxy clusters, assuming hydrostatic equilibrium and energy balance between radiative cooling and thermal conduction. For five clusters, A1795, A1835, A2199, A2390, and RX J1347.5-1145, the model gives a good description of the observed radial profiles of electron density and temperature, provided that we take the thermal conductivity κ to be about 30% of the Spitzer conductivity. Since the required κ is consistent with the recent theoretical estimate of Narayan & Medvedev for a turbulent magnetized plasma, we consider a conduction-based equilibrium model to be viable for these clusters. We further show that the hot gas is thermally stable because of the presence of conduction. For five other clusters, A2052, A2597, Hydra A, Ser 159-03, and 3C 295, the model requires unphysically large values of κ to fit the data. These clusters must have some additional source of heat, possibly an active galactic nucleus, since all the clusters have strong radio galaxies at their centers. We suggest that thermal conduction, although not dominant in these clusters, may nevertheless play a significant role by preventing the gas from becoming thermally unstable.
Towards a spectral technique for determining material geometry around evolved stars: application to HD 179821

HD 179821 is an evolved star of unknown progenitor mass range (either post-asymptotic giant branch or post-red supergiant) exhibiting a double-peaked spectral energy distribution (SED) with as harp rise from∼ 8t o 20μm. Such features have been associated with ejected dust shells or inwardly truncated circumstellar discs. In order to compare SEDs from both systems, we employ a spherically symmetric radiative transfer code and compare it to a radiative, inwardly truncated disc code. As a case study, we model the broad-band SED of HD 179821 using both codes. Shortward of 40 μm, we find that both models produce equivalent fits to the data. However, longward of 40 μm, the radial density distribution and corresponding broad range of disc temperatures produce excess emission above our spherically symmetric solutions and observations. For HD 179821, our best fit consists of a T eff = 7000 K central source characterized by τV ∼ 1.95 and surrounded by a radiatively driven, spherically symmetric dust shell. The extinction of the central source reddens the broad-band colours so that they resemble aT eff = 5750 K photosphere. We believe that HD 179821 contains a hotter central star than previously thought. Our results provide an initial step towards a technique to distinguish geometric differences from spectral modelling.
NTC-affected ignition in nonpremixed counterflow

Using n-heptane as the model fuel, the role of the Negative Temperature Coefficient (NTC) chemistry on ignition is computationally studied for both homogeneous mixtures and nonpremixed counterflow. For homogeneous mixtures, results show that ignition occurs in two-stages within the NTC temperature regime, with the duration and temperature increment decreasing with increasing initial temperature for the first ignition stage, leading to increased duration of the second ignition stage and thereby the observed NTC-behavior. For the nonpremixed counterflow, results show that a secondary S-curve is developed on the lower branch of the conventional, primary S-curve for sufficiently low strain rates and/or sufficiently high pressures, with its own distinct ignition–extinction turning points. Sensitivity analysis and Chemical Explosive Mode Analysis (CEMA) show that this secondary S-curve is controlled by the low-temperature NTC-chemistry, with heat release negligible for states on its lower branch and discernable for states on its upper branch and hence assuming the characteristics of a weakly-burning flame. The possible existence of one- and two-staged ignition in the counterflow is observed, and its dependence on the flow strain rate and system pressure are identified.
Service innovation in manufacturing

Purpose – The purpose of this paper is to report on nine in‐depth case histories of manufacturing firms introducing significant new service innovations. Manufacturing firms are under increasing pressure to diversify into lines of business that offer unique contributions to long term profitability and this paper increases understanding of how incumbent firms successfully accomplish this transition.Design/methodology/approach – Using analytical induction the authors sample published announcements of significant new service offerings by well‐established manufacturing firms. An example of this type of service innovation would be General Motor's offering of OnStar remote driver support systems (not included in this sample). A total of nine cases (43 percent of the companies contacted) participated in this case study approach.Findings – The paper identifies two primary strategies pursued by these firms development and launch of significant new service innovations representing important diversification moves for...
The large-scale structure of flare-associated interplanetary shocks

The large-scale structure of flare-associated interplanetary shocks is investigated by examining the properties of 116 shocks which originated in solar flare events during a 18.7-year period commencing mid-May 1967. The best average representation of these shocks is an expansion which is uniform over about 100 deg. The highest compression ratio across the shock is about 15 deg west of the radial from the flare site. The loose coupling of shocks and their drivers is supported by the observation that drivers are generally only detected for shocks originating near central meridian. A comparison of the numbers of shocks per year with the numbers of sudden commencement geomagnetic storms indicates that the percentage of shocks at 1 AU which originate in flare events is less than 50 percent. Many shock-flare associations made in the past are probably in error.
Constructing a small strain potential for multi-scale modeling

Simulation of bulk materials with some components locally far from equilibrium usually requires a computationally intensive quantum mechanical description to capture the relevant mechanisms (e.g. effects of chemistry). Multi-scale modeling entails a compromise whereby, the most accurate quantum description is used only where needed and the remaining bulk of the material is replaced by a simpler classical system of point particles. The problem of constructing an appropriate potential energy function for this classical system is addressed here. For problems relating to fracture, a consistent embedding of a quantum (QM) domain in its classical (CM) environment requires that the classical system should yield the same structure and elastic properties as the QM domain for states near equilibrium. It is proposed that an appropriate classical potential can be constructed using ab initio data on the equilibrium structure and weakly strained configurations calculated from the quantum description, rather than the mo...
Progress in Understanding Electron-Transfer Reactions at Semiconductor/Liquid Interfaces

This article describes theoretical treatments and experimental data focused on the rates of interfacial electron-transfer processes at semiconductor/liquid contacts. These systems are of practical interest because such electron transfers are a critical factor in understanding the behavior of photoelectrochemical cells as energy conversion devices. These processes are of theoretical interest because the description of how a delocalized charge carrier in a semiconducting solid reacts with a localized redox acceptor that is dissolved in the liquid electrolyte is a relatively undeveloped area of electron-transfer theory. The general principles of these processes, a discussion of past and present experimental data, and a comparison between theoretical expectations and experimental observations on a variety of semiconducting electrode systems are the main focus of this article.
Ftir Studies of Water and Ammonia Decomposition on Silicon Surfaces

Fourier transform infrared (FTIR) transmission spectroscopy. was used to monitor the decomposition of H 2 O (D 2 O) and NH 3 (ND 3 ) on silicon surfaces. Experiments were performed in-situ in an ultra-high vacuum (UHV) chamber using high surface area poroussilicon samples. The FTIR spectra revealed that H 2 O dissociates upon adsorption at 300K to form SiH and SiNH 2 surface species. NH 3 also issociates upon adsorption at 300 K to form SiH and SiOH 2 species. Silicon samples with saturation exposures of H 2 O and NH 3 were progressively annealed from 300 K to 860 K. The FTIR spectra of an H 2 O-saturated silicon surface revealed that the SiOH species decomposed to form a silicon oxide species and additional surface hydrogen between 460 K and 580 K. Likewise, the SiNH 2 species decomposed between 540 K and 660 K to produce silicon nitride and additional surface hydrogen. In both cases, the Sill surface species decreased as H 2 desorption from the silicon surface was observed above 700 K.
Howard M. Temin - 10 December 1934--9 February 1994.

Howard M. Temin died on 9 February 1994, at the age 59. He was awarded the Nobel Prize in 1975 for the discovery of a new mechanism of genome reproduction, called ‘reverse transcription’. Transcription is the term used to identify the transfer of information from genes made of DNA to their messengers, which are made of RNA. The messengers then transfer the information to the proteins, which express the information of the genes. In reverse transcription, on the contrary, the information is transferred from RNA to DNA as part of a reproductive cycle. Howard Temin (and independently David Baltimore) discovered the new mechanism by studying a class of viruses that cause leukemias or cancer in a variety of animals. The discovery was sensational because at that time biologists had become used to the idea that information is transferred from DNA to RNA and not vice versa. As often happens, this was considered a ‘central dogma of molecular biology’. However, the only reason for accepting the dogma was that nobody had shown that it could happen the other way. Nevertheless, the breaking of the dogma by Temin and Baltimore had a very strong resonance.
Active Control of Supersonic Base Flows with Electric Arc Plasma Actuators

The current paper evaluates the control authority of electric arc plasma actuators on a supersonic axisymmetric base flow for several actuator geometries, frequencies, forcing modes, duty cycles/on-times, and currents. The disturbances were tracked in time with phase-locked schlieren imaging and particle image velocimetry. The actuators caused moderate influences on the axisymmetric shear-layer velocity profile and base pressure. The most substantial changes to the shear layer and base pressure were noted for the highest current and duty cycle experiments. At 1 A and 20% duty cycle, the base pressure was reduced by 3.5%. Similar changes were noted for all modes and a range of Strouhal numbers StD from about 1.11 to 3.33 (10–30 kHz). Increases in duty cycle between 4 and 20% caused a nearly linear decrease in base pressure. Disturbances were tracked at all frequencies and translated along the shear layer at a convective velocity of 430±20 m/s. A fairly clear trend of increasing velocity disturbance amplit...
Pregnancy complicated by cardiac disease: Maternal and perinatal outcome

We report maternal and perinatal outcome in pregnancies complicated by maternal cardiac disease. A retrospective review of 54 women with cardiac disease, managed through 71 pregnancies from February 1981, through July 1991, was conducted. Tricuspid atresia and pulmonary hypertension were associated with a 50% maternal mortality rate and a 67% incidence of intrauterine growth retardation. Cardiomyopathy was associated with prematurity and low birthweight. Atrial or ventricular septal defects and stenotic lesions of the outflow tracts were generally not associated with adverse maternal or perinatal outcome. Women with previous myocardial infarction, corrected tetralogy of Fallot, aortic or mitral insufficiency, and mitral valve prolapse generally tolerated pergnancy, labor, and delivery without adverse sequelae in this review. Although peripartum cardiomyopathy was associated with low birthweight, pregnancies were successfully managed with intensive monitoring. Tricuspid atresia and pulmonary hypertension r...
A kinetic thermodynamics approach to the psychology of fluctuations in financial markets

Abstract We derive a set of equations which are a simple model for investor behavior in a theoretical financial market. The model incorporates the emotional aspect of investor sentiment with memory of price history which decays exponentially in time. Within this model, the emotional reaction of the body of investors is to buy when the recent price has been increasing and sell when it has been decreasing. The rational motivations are based on capitalizing on the difference between the price and intrinsic value, with the possibility of some inertia in taking action. These two competing effects provide the basis for fluctuations and instability.
Gut microbiota and the paradox of cancer immunotherapy.

It is recently shown that beneficial environmental microbes stimulate integrated immune and neuroendocrine factors throughout the body, consequently modulating regulatory T lymphocyte phenotypes, maintaining systemic immune balance, and determining the fate of preneoplastic lesions towards regression while sustaining whole body good health. Stimulated by a gut microbiota-centric systemic homeostasis hypothesis, we set out to explore the influence of the gut microbiome to explain the paradoxical roles of regulatory T lymphocytes in cancer development and growth. This paradigm shift places cancer prevention and treatment into a new broader context of holobiont engineering to cultivate a tumor-suppressive macroenvironment.
Adaptive Slicing of Moving Least Squares Surfaces: Toward Direct Manufacturing of Point Set Surfaces

Rapid advancement of 3D sensing techniques has led to dense and accurate point cloud of an object to be readily available. The growing use of such scanned point sets in product design, analysis, and manufacturing necessitates research on direct processing of point set surfaces. In this paper, we present an approach that enables the direct layered manufacturing of point set surfaces. This new approach is based on adaptive slicing of moving least squares (MLS) surfaces. Salient features of this new approach include the following: (I) It bypasses the laborious surface reconstruction and avoids model conversion induced accuracy loss. (2) The resulting layer thickness and layer contours are adaptive to local curvatures, and thus it leads to better surface quality and more efficient fabrication. (3) The curvatures are computed from a set of closed formula based on the MLS surface. The MLS surface naturally smoothes the point cloud and allows upsampling and downsampling, and thus it is robust even for noisy or sparse point sets. Experimental results on both synthetic and scanned point sets are presented.
Intramolecular Transannulation of Alkynyl Triazoles via Alkyne-Carbene Metathesis Step: Access to Fused Pyrroles

An intramolecular Rh-catalyzed transannulation reaction of alkynyl triazoles has been developed. This method allows efficient construction of various 5,5-fused pyrroles, including tetrahydropyrrolo and spiro systems. The method demonstrates excellent functional group compatibility. A rhodium carbene–alkyne metathesis mechanism is proposed for this transformation.