cssi/SciSciGPT-SciSciNet huggingface dataset:
JUPITER WILL BECOME A HOT JUPITER: CONSEQUENCES OF POST-MAIN-SEQUENCE STELLAR EVOLUTION ON GAS GIANT PLANETS

When the Sun ascends the red giant branch (RGB), its luminosity will increase and all the planets will receive much greater irradiation than they do now. Jupiter, in particular, might end up more highly irradiated than the hot Neptune GJ 436b and, hence, could appropriately be termed a hot Jupiter. When their stars go through the RGB or asymptotic giant branch stages, many of the currently known Jupiter-mass planets in several-AU orbits will receive levels of irradiation comparable to the hot Jupiters, which will transiently increase their atmospheric temperatures to ~1000?K or more. Furthermore, massive planets around post-main-sequence stars could accrete a non-negligible amount of material from the enhanced stellar winds, thereby significantly altering their atmospheric chemistry as well as causing a significant accretion luminosity during the epochs of most intense stellar mass loss. Future generations of infrared observatories might be able to probe the thermal and chemical structure of such hot Jupiters' atmospheres. Finally, we argue that, unlike their main-sequence analogs (whose zonal winds are thought to be organized in only a few broad, planetary-scale jets), red-giant hot Jupiters should have multiple, narrow jets of zonal winds and efficient day-night redistribution.
Worth of watersheds: a producer surplus approach for valuing drought mitigation in Eastern Indonesia

This study combines hydrological modeling with applied micro-econometric techniques to value a complex ecosystem service: drought mitigation provided by tropical forested watersheds to agrarian communities. Spatial variation in current baseflow allows estimation of drought mitigation values as the marginal profit accruing to agricultural households. The paper shows that this uncommon focus on producer (not consumer) surplus measures is appropriate for valuation as long as markets for commodities related to the environmental services are complete. For the typical household, the estimated marginal profit is positive, validating the central hypothesis that baseflow makes positive contributions to agricultural profits. There is some evidence, however, that increased watershed protection will increase profits through greater baseflow only in watersheds with a unique mix of physio-graphic and climatic features. The paper evaluates and provides some support for the hypothesis, put forward by hydrological science and the Indonesian Government, that protected watersheds can supply latent and unrecognized ecosystem services to local people.
An adaptive successive over-relaxation method for computing the Black–Scholes implied volatility

A new successive over-relaxation method to compute the Black–Scholes implied volatility is introduced. Properties of the new method are fully analysed, including global well-definedness, local convergence, as well as global convergence. Quadratic order of convergence is achieved by either a dynamic relaxation or transformation of sequence technique. The method is further enhanced by introducing a rational approximation on initial values. Numerical implementation shows that uniformly in a very large domain, the new method converges to the true implied volatility with very few iterations. Overall, the new method achieves a very good combination of efficiency, accuracy and robustness.
A Theory of Capital Controls as Dynamic Terms-of-Trade Manipulation

We develop a theory of capital controls as dynamic terms-of-trade manipulation. We study an infinite-horizon endowment economy with two countries. One country chooses taxes on international capital flows in order to maximize the welfare of its representative agent, while the other country is passive. We show that a country growing faster than the rest of the world has incentives to promote domestic savings by taxing capital inflows or subsidizing capital outflows. Although our theory of capital controls emphasizes interest rate manipulation, the pattern of borrowing and lending, per se, is irrelevant.
Clinical evidence of early acute lung injury often precedes the diagnosis of ALI.

Background Acute lung injury (ALI) has been primarily defined in patients who require positive pressure ventilation. As a result, the clinical characteristics of patients with early ALI (EALI) prior to the need for mechanical ventilation have not been well characterized. Early identification of patients with ALI and the impending need for positive pressure ventilation could define a study population for trials of novel therapies. Methods We analyzed clinical data from 93 patients at 12, 24, and 48 hours prior to the standard diagnosis of ALI. The time of ALI diagnosis was defined when patients were mechanically ventilated and met the 1994 American-European Consensus Conference diagnostic criteria for ALI. Results The majority of patients with ALI presented to the hospital more than 24 hours prior to developing ALI. Specifically, 73% presented more than 12 hours prior to diagnosis, and 57% presented more than 24 hours prior to diagnosis. Of patients hospitalized for at least 12 hours prior to ALI diagnosis, 94% had either bilateral infiltrates on chest radiograph, tachypnea, or an oxygen requirement greater than 2 L/min; 79% and 48% had 2 and 3 of these abnormalities, respectively. Conclusion The majority of hospitalized patients who are destined to develop ALI demonstrate tachypnea, increased oxygen requirements, and/or bilateral infiltrates on chest radiograph more than 12 hours prior to meeting criteria for diagnosis. Some patients with EALI may be identified prior to meeting diagnostic criteria during a potential therapeutic window.
Child Health and the 1988-92 Economic Crisis in Peru

The effect of economic crises on child health is a topic of great policy importance. The authors use data from the Demographic and Health Surveys (DHS) to analyze the impact of the profound 1988-92 economic crisis in Peru on infant mortality and anthropometrics. They show that there was an increase in the infant mortality rate of about 2.5 percentage points for children born in late 1989 and 1990, implying that about 17,000 more children died than would have in the absence of the crisis. The authors also present suggestive evidence that the crisis affected children's nutritional status. In 1992 children under the age of 6 who had been exposed to the crisis were shorter than same-aged children in 1996 and 2000. The authors do not have data on child height prior to the crisis, but the age profile of changes in nutritional status and the fact that the 1996 and 2000 height-for-age schedules are very similar to each other both suggest that the 1992 values represent declines from previous levels. Accounting for the precise source of the increase in infant mortality and in malnutrition is difficult, but it appears that both the decrease in household incomes and the collapse in expenditures on public health played an important role.
HKR Theorem for Smooth S-algebras

Abstract We derive an etale descent formula for topological Hochschild homology and prove a HKR theorem for smooth S-algebras.
Ultrafast Optical-Pump Terahertz-Probe Spectroscopy of the Carrier Relaxation and Recombination Dynamics in Epitaxial Graphene

The ultrafast relaxation and recombination dynamics of photogenerated electrons and holes in epitaxial graphene are studied using optical-pump terahertz-probe spectroscopy. The conductivity in graphene at terahertz frequencies depends on the carrier concentration as well as the carrier distribution in energy. Time-resolved studies of the conductivity can therefore be used to probe the dynamics associated with carrier intraband relaxation and interband recombination. We report the electron-hole recombination times in epitaxial graphene for the first time. Our results show that carrier cooling occurs on subpicosecond time scales and that interband recombination times are carrier density dependent.
How the Innate Immune System Senses Trouble and Causes Trouble

The innate immune system is the first line of defense in response to nonself and danger signals from microbial invasion or tissue injury. It is increasingly recognized that each organ uses unique sets of cells and molecules that orchestrate regional innate immunity. The cells that execute the task of innate immunity are many and consist of not only “professional” immune cells but also nonimmune cells, such as renal epithelial cells. Despite a high level of sophistication, deregulated innate immunity is common and contributes to a wide range of renal diseases, such as sepsis-induced kidney injury, GN, and allograft dysfunction. This review discusses how the innate immune system recognizes and responds to nonself and danger signals. In particular, the roles of renal epithelial cells that make them an integral part of the innate immune apparatus of the kidney are highlighted.
Adult height in girls with central precocious puberty treated with gonadotropin-releasing hormone agonist with or without growth hormone.

Purpose: There is controversy surrounding the growth outcomes of treatment with gonadotropin-releasing hormone agonist (GnRHa) in central precocious puberty (CPP). We analyzed height preservation after treatment with GnRHa with and without growth hormone (GH) in girls with CPP. Methods: We reviewed the medical records of 82 girls with idiopathic CPP who had been treated with GnRHa at Severance Children’s Hospital from 2004 to 2014. We assessed the changes in height standard deviation score (SDS) for bone age (BA), and compared adult height (AH) with midparental height (MPH) and predicted adult height (PAH) during treatment in groups received GnRHa alone (n=59) or GnRHa plus GH (n=23). Results: In the GnRHa alone group, the height SDS for BA was increased during treatment. AH (160.4±4.23 cm) was significantly higher than the initial PAH (156.6±3.96 cm) (P<0.001), and it was similar to the MPH (159.9±3.52 cm). In the GnRHa plus GH group, the height SDS for BA was also increased during treatment. AH (159.3±5.33 cm) was also higher than the initial PAH (154.6±2.55 cm) (P<0.001), which was similar to the MPH (158.1±3.31 cm). Height gain was slightly higher than that in the GnRHa alone group, however it statistically showed no significant correlation with GH treatment. Conclusion: In CPP girls treated with GnRHa, the height SDS for BA was increased, and the AH was higher than the initial PAH. Combined GH treatment showed a limited increase in height gain.
Arbitrary function generator for APS injector synchrotron correction magnets

The arbitrary function generator (AFG) design is based on scanning out encoded data from a semiconductor memory, a first-in-first-out (FIFO) device. The data input consists of a maximum of 20 correction values specified within the acceleration window. Additional points between these values are then linearly interpolated to create a uniformly spaced 1000 data-point function stored in the FIFO. Each point, encoded as a 3-b value is canned out in synchronism with the injection pulse and used to clock the up/down counter driving the DAC (digital-to-analog converter). The DAC produces the analog reference voltage used to control the magnet current. >
The Search for Deep Pockets: Is "Extended Liability" Expensive Liability?

This article examines the effects of extending liability from a producer firm that generates and controls risk to firms who profitably transact with the producer but cannot directly control risk. Examples of extended liability include the liability of retailers for design defects in the products the retailer sells, and the liability of waste shippers for leaks in the landfills that dispose of the shipper's waste. We show that while extending liability forces greater joint cost internalization, it need not improve welfare. The reason is that extended liability can lead to two types of cost-increasing distortions. First, in order to externalize liabilities, the firms to whom liability is extended may reduce capital investment and/or increase output. Second, extended liability can distort the pattern of transactions between riskgenerating firms and those with whom they contract, since deep-pocketed firms have an incentive to avoid transactions with more shallow-pocketed firms. To evaluate the ultimate desirability of extending liability, both of these welfare losses must be balanced against the benefit of improved deterrence.
Constellation labeling maps for low error floors

A constellation labeling map is the assignment of a bit pattern to each symbol in a signal-set constellation. In a system with iterative decoding and demodulation, the error floor of the bit error rate is highly dependent on the labeling map. A simple class of labeling maps that significantly lower the error floors is presented. Examples show the applications of the proposed mapping to multiple phase-shift keying (MPSK), quadrature amplitude modulation (QAM), and continuous-phase frequency-shift keying (CPFSK). Simulation results indicate that the proposed labeling maps are comparable to or better than other labeling maps in providing a low error floor. A major advantage of the proposed labeling maps is that they are easily generated even when the alphabet size is large.
Discovery of Reflection Nebulosity around Five Vega-like Stars

Coronagraphic optical observations of six Vega-like stars reveal reflection nebulosities, five of which were previously unknown. The nebulosities illuminated by HD 4881, HD 23362, HD 23680, HD 26676, and HD 49662 resemble that of the Pleiades, indicating an interstellar origin for dust grains. The reflection nebulosity around HD 123160 has a double-arm morphology, but no disklike feature is seen as close as 25 from the star in K-band adaptive optics data. We demonstrate that a uniform density dust cloud surrounding HD 23362, HD 23680, and HD 123160 can account for the observed 12-100 μm spectral energy distributions. For HD 4881, HD 26676, and HD 49662, an additional emission source, such as from a circumstellar disk or nonequilibrium grain heating, is required to fit the 12-25 μm data. These results indicate that in some cases, particularly for Vega-like stars located beyond the Local Bubble (>100 pc), the dust responsible for excess thermal emission may originate from the interstellar medium rather than from a planetary debris system.
Variable-length channel quantizers for maximum diversity and array gains

We consider a t × 1 multiple-antenna fading channel with quantized channel state information at the transmitter (CSIT). Our goal is to maximize the diversity and array gains that are associated with the symbol error rate (SER) performance of the system. It is well-known that for both beamforming and precoding strategies, finite-rate fixed-length quantizers (FLQs) cannot achieve the full-CSIT diversity and array gains. In this work, for any function f(P) ϵ ω(1), we construct variable-length quantizers (VLQs) that can achieve these full-CSIT gains with rates 1 + (/(P) log P)/P and 1 + f(P)/Pt for the beamforming and precoding strategies, respectively, where P is the power constraint of the transmitter. We also show that these rates are the best possible up to o(l) multipliers in their P-dependent terms. In particular, although the full-CSIT SER is not achievable at any (even infinite) feedback rate, the full-CSIT diversity and array gains can be achieved with a feedback rate of 1 bit per channel state asymptotically as P → ∞.
A Hybrid Analog-Digital Parameter Optimizer for ASTRAC II:

A new automatic multiparameter optimizer for iter ative differential analyzers employs sequential ran dom parameter perturbation. The nominal parameter point changes whenever the random perturbations improve the system performance measure. Binary counters operate simple digital-to-analog converters to implement parameter storage, multiplication, and step-size changes. All-digital logic yields different types of random perturbations, viz., simple random walk, random walk with reflecting or absorbing bar riers, and various types of correlation over successive perturbations.
Pre-test market evaluation of new packaged goods : a model and measurement methodology

The substantial failure rate of new packaged goods in test markets has stimulated firms to seek improved methods of pre-test-market evaluation. A set of measurement procedures and models designed t...
Determinantal random point fields

This paper contains an exposition of both recent and rather old results on determinantal random point fields. We begin with some general theorems including proofs of necessary and sufficient conditions for the existence of a determinantal random point field with Hermitian kernel and of a criterion for weak convergence of its distribution. In the second section we proceed with examples of determinantal random fields in quantum mechanics, statistical mechanics, random matrix theory, probability theory, representation theory, and ergodic theory. In connection with the theory of renewal processes, we characterize all Hermitian determinantal random point fields on and with independent identically distributed spacings. In the third section we study translation-invariant determinantal random point fields and prove the mixing property for arbitrary multiplicity and the absolute continuity of the spectra. In the last section we discuss proofs of the central limit theorem for the number of particles in a growing box and of the functional central limit theorem for the empirical distribution function of spacings.
A trajectory piecewise-linear approach to model order reduction and fast simulation of nonlinear circuits and micromachined devices

In this paper, we present an approach to nonlinear model reduction based on representing a nonlinear system with a piecewise-linear system and then reducing each of the pieces with a Krylov projection. However, rather than approximating the individual components as piecewise linear and then composing hundreds of components to make a system with exponentially many different linear regions, we instead generate a small set of linearizations about the state trajectory which is the response to a "training input." Computational results and performance data are presented for an example of a micromachined switch and selected nonlinear circuits. These examples demonstrate that the macromodels obtained with the proposed reduction algorithm are significantly more accurate than models obtained with linear or recently developed quadratic reduction techniques. Also, we propose a procedure for a posteriori estimation of the simulation error, which may be used to determine the accuracy of the extracted trajectory piecewise-linear reduced-order models. Finally, it is shown that the proposed model order reduction technique is computationally inexpensive, and that the models can be constructed "on the fly," to accelerate simulation of the system response.
Approximating the Maximum Overlap of Polygons under Translation

Let $$P$$P and $$Q$$Q be two simple polygons in the plane of total complexity n, each of which can be decomposed into at most k convex parts. We present a $$(1-\varepsilon )$$(1-ź)-approximation algorithm, for finding the translation of $$Q$$Q, which maximizes its area of overlap with $$P$$P. Our algorithm runs in $$O\left( {c n}\right) $$Ocn time, where c is a constant that depends only on k and $$\varepsilon $$ź. This suggests that for polygons that are "close" to being convex, the problem can be solved (approximately), in near linear time.
Luminescent Carbon Nanodots: Emergent Nanolights

Similar to its popular older cousins the fullerene, the carbon nanotube, and graphene, the latest form of nanocarbon, the carbon nanodot, is inspiring intensive research efforts in its own right. These surface-passivated carbonaceous quantum dots, so-called C-dots, combine several favorable attributes of traditional semiconductor-based quantum dots (namely, size- and wavelength-dependent luminescence emission, resistance to photobleaching, ease of bioconjugation) without incurring the burden of intrinsic toxicity or elemental scarcity and without the need for stringent, intricate, tedious, costly, or inefficient preparation steps. C-dots can be produced inexpensively and on a large scale (frequently using a one-step pathway and potentially from biomass waste-derived sources) by many approaches, ranging from simple candle burning to in situ dehydration reactions to laser ablation methods. In this Review, we summarize recent advances in the synthesis and characterization of C-dots. We also speculate on their future and discuss potential developments for their use in energy conversion/storage, bioimaging, drug delivery, sensors, diagnostics, and composites.
Simultaneous radiative and convective heat transfer in an absorbing, emitting, and scattering medium in slug flow between parallel plates

The problem of coupled radiation and convection to a medium in slug flow between infinite, parallel plates was formulated in terms of discrete fluxes. Steady state, uniform heat input, and gray boundaries were assumed. The effects of absorption, emission, scattering, and flow were taken into account. For the general case where all these effects are present, it was necessary to approximate the fourth order temperature term by a truncated Taylor series. This approximation was not necessary for the special case where conductivity of the medium is negligible. Approximate, analytical solutions in closed-form for profiles of temperature, radiant fluxes, and heat fluxes were obtained for both the special case and the general case. Sample results are presented, showing the effects of convection, absolute temperature, absorption coefficient, scattering coefficient, and wall emissivities. The two cases of equal wall temperatures and unequal wall temperatures were both examined. It was found that for a fluid with the thermal conductivity of air, radiation can account for 60 to 95% of total heat transfer in the temperature range of 900 to 2800 deg R. It was also found that for some situations, the scattering phenomenon can have a much greater effect on heat transfer than themore » absorption and emission phenomena. (auth)« less
LONG GAMMA-RAY TRANSIENTS FROM COLLAPSARS

In the collapsar model for common gamma-ray bursts (GRBs), the formation of a centrifugally supported disk occurs during the first {approx}10 s following the collapse of the iron core in a massive star. This only occurs in a small fraction of massive stellar deaths, however, and requires unusual conditions. A much more frequent occurrence could be the death of a star that makes a black hole and a weak or absent outgoing shock, but in a progenitor that only has enough angular momentum in its outermost layers to make a disk. We consider several cases where this is likely to occur-blue supergiants with low mass-loss rates, tidally interacting binaries involving either helium stars or giant stars, and the collapse to a black hole of very massive pair-instability supernovae. These events have in common the accretion of a solar mass or so of material through a disk over a period much longer than the duration of a common GRB. A broad range of powers is possible, 10{sup 47}-10{sup 50} erg s{sup -1}, and this brightness could be enhanced by beaming. Such events were probably more frequent in the early universe where mass-loss rates were lower. Indeed, this could be one ofmore » the most common forms of gamma-ray transients in the universe and could be used to study first generation stars. Several events could be active in the sky at any one time. Recent examples of this sort of event may have been the Swift transients Sw-1644+57, Sw-2058+0516, and GRB 101225A.« less
The Effects of Mortality on Fertility: Population Dynamics After a Natural Disaster

Understanding how mortality and fertility are linked is essential to the study of population dynamics. We investigate the fertility response to an unanticipated mortality shock that resulted from the 2004 Indian Ocean tsunami, which killed large shares of the residents of some Indonesian communities but caused no deaths in neighboring communities. Using population-representative multilevel longitudinal data, we identify a behavioral fertility response to mortality exposure, both at the level of a couple and in the broader community. We observe a sustained fertility increase at the aggregate level following the tsunami, which was driven by two behavioral responses to mortality exposure. First, mothers who lost one or more children in the disaster were significantly more likely to bear additional children after the tsunami. This response explains about 13 % of the aggregate increase in fertility. Second, women without children before the tsunami initiated family-building earlier in communities where tsunami-related mortality rates were higher, indicating that the fertility of these women is an important route to rebuilding the population in the aftermath of a mortality shock. Such community-level effects have received little attention in demographic scholarship.
Holographic studies of entanglement entropy in superconductors

We present the results of our studies of the entanglement entropy of a super- conducting system described holographically as a fully back-reacted gravity system, with a stable ground state. We use the holographic prescription for the entanglement entropy. We uncover the behavior of the entropy across the superconducting phase transition, showing the reorganization of the degrees of freedom of the system. We exhibit the behaviour of the entanglement entropy from the superconducting transition all the way down to the ground state at T = 0. In some cases, we also observe a novel transition in the entanglement entropy at intermediate temperatures, resulting from the detection of an additional length scale.
Elemental sulfur coarsening kinetics.

Elemental sulfur exists is a variety of forms in natural systems, from dissolved forms (noted as S8(diss) or in water as S8(aq)) to bulk elemental sulfur (most stable as α-S8). Elemental sulfur can form via several biotic and abiotic processes, many beginning with small sulfur oxide or polysulfidic sulfur molecules that coarsen into S8 rings that then coalesce into larger forms: 1 Formation of elemental sulfur can be possible via two primary techniques to create an emulsion of liquid sulfur in water called sulfur sols that approximate some mechanisms of possible elemental sulfur formation in natural systems. These techniques produce hydrophobic (S8(Weimarn)) and hydrophilic (S8(polysulfide)) sols that exist as nanoparticle and colloidal suspensions. These sols begin as small sulfur oxide or polysulfidic sulfur molecules, or dissolved S8(aq) forms, but quickly become nanoparticulate and coarsen into micron sized particles via a combination of classical nucleation, aggregation processes, and/or Ostwald ripening. We conducted a series of experiments to study the rate of elemental sulfur particle coarsening using dynamic light scattering (DLS) analysis under different physical and chemical conditions. Rates of nucleation and initial coarsening occur over seconds to minutes at rates too fast to measure by DLS, with subsequent coarsening of S8(nano) and S8(sol) being strongly temperature dependent, with rates up to 20 times faster at 75°C compared to 20°C. The addition of surfactants (utilizing ionic and nonionic surfactants as model compounds) results in a significant reduction of coarsening rates, in addition to known effects of these molecules on elemental sulfur solubility. DLS and cryo-SEM results suggest coarsening is largely a product of ripening processes rather than particle aggregation, especially at higher temperatures. Fitting of the coarsening rate data to established models for Ostwald ripening additionally support this as a primary mechanism of coarsening. Elemental sulfur sols coarsen rapidly at elevated temperatures and experience significant effects on both solubility and particle coarsening kinetics due to interaction with surfactants. Growth of elemental sulfur nanoparticles and sols is largely governed by Ostwald ripening processes.
Welfare policy: The administrative frontier

The process of national welfare reform has been overtaken by local reform as states implement experimental programs under federal waivers. Most of these initiatives attempt to enforce work or otherwise control the lives of the dependent in return for support. Research, which traditionally stressed the social and economic aspects of welfare or poverty, must be reoriented to address the administrative issues raised by the emerging paternalism. A combination of field interviewing and analyses of reporting data can track implementation and connect program operations to outcomes. Such research assesses program performance less definitively than experimental trials do but is more useful to operators and more relevant to current program goals. The frontiers of welfare research, like welfare policy, are institutional.
SELECTED TOPICS IN PLANCK-SCALE PHYSICS

We review a few topics in Planck-scale physics, with emphasis on possible manifestations in relatively low energy. The selected topics include quantum fluctuations of spacetime, their cumulative effects, uncertainties in energy–momentum measurements, and low energy quantum-gravity phenomenology. The focus is on quantum-gravity-induced uncertainties in some observable quantities. We consider four possible ways to probe Planck-scale physics experimentally: (i) looking for energy-dependent spreads in the arrival time of photons of the same energy from GRBs; (ii) examining spacetime fluctuation-induced phase incoherence of light from extragalactic sources; (iii) detecting spacetime foam with laser-based interferometry techniques; (iv) understanding the threshold anomalies in high energy cosmic ray and gamma ray events. Some other experiments are briefly discussed. We show how some physics behind black holes, simple clocks, simple computers, and the holographic principle is related to Planck-scale physics. We also discuss a formulation of the Dirac equation as a difference equation on a discrete Planck-scale spacetime lattice, and a possible interplay between Planck-scale and Hubble-scale physics encoded in the cosmological constant (dark energy).
Reproductive Biology, Technology, and Gender Inequality: An Autobiographical Essay

Ignorance of biodata is costly in sociology. Gender theorists remain unaware that until the demographic transition, infants were suckled every 15 minutes for two years, less often another two. A nearly continuous cycle of pregnancy and lactation barred women from the activities that brought the most prestige and power until the advent of modern sanitation after 1880. Women entered the public arena in large number only after technology altered the social consequences of human physiology. Yet wives still spend twice as much time in housework and child care as husbands. Data about the effects of both biology and culture on social interaction would enhance studies of ethnocentrism within the household.
Asymptotic freedom: From paradox to paradigm

In theoretical physics, paradoxes are good. That's paradoxical, since a paradox appears to be a contradiction, and contradictions imply serious error. But Nature cannot realize contradictions. When our physical theories lead to paradox we must find a way out. Paradoxes focus our attention, and we think harder. When David Gross and I began the work that led to this Nobel Prize (1–3)† in 1972, we were driven by paradoxes. In resolving the paradoxes, we were led to discover a new dynamical principle, asymptotic freedom. This principle, in turn, has led to an expanded conception of fundamental particles, a new understanding of how matter gets its mass, a new and much clearer picture of the early universe, and new ideas about the unity of Nature's forces. Today I'd like to share with you the story of these ideas. Paradox 1: Quarks Are Born Free, but Everywhere They Are in Chains. The first paradox was phenomenological. Near the beginning of the 20th century, after pioneering experiments by Rutherford, Geiger, and Marsden, physicists discovered that most of the mass and all of the positive charge inside an atom is concentrated in a tiny central nucleus. In 1932, Chadwick discovered neutrons, which together with protons could be considered as the ingredients out of which atomic nuclei could be constructed. But the known forces, gravity and electromagnetism, were insufficient to bind protons and neutrons tightly together into objects as small as the observed nuclei. Physicists were confronted with a new force, the most powerful in Nature. Understanding this new force became a major challenge in fundamental physics. For many years, physicists gathered data to address that challenge, basically by bashing protons and neutrons together and studying what came out. The results that emerged from these studies, however, were complicated and hard …
Minimizing the Number of Switchings in an SS/TDMA System

In this paper, we investigate the problem of constructing a TDMA frame for a multibeam satellite system. Our objective is to permit the transmission of a given pattern of traffic, while ensuring that the number of times that the on-board switch needs to be reconfigured is minimized. We find that the underlying optimization problem is computationally intractable, but go on to suggest an efficient heuristic algorithm which we validate through experiments on randomly generated traffic patterns.
Engineering the Virtual Node Layer for Reactive MANET Routing

The VNLayer approach [1] simplifies software development for MANET by providing the developers an abstraction of a network divided into fixed geographical regions, each containing a virtual server for network services. In this paper, we present our study on reactive MANET routing over the VNLayer. During this research, we identified in our initial VNLayer implementation three major limitations that lead to heavy control traffic, long forwarding paths and frequent message collisions in MANET routing. To address the problems, we changed the assumptions made by the VNLayer on the link layer and extended the operations allowed by VNLayer. This results in a VNLayer implementation that can be tuned to optimize the performance of traffic intensive applications (such as routing) while maintaining their simplicity and robustness. Simulation results showed that VNAODV, a VNLayer based routing protocol adapted from AODV [4], delivers more packets, generates less routing traffic and creates more stable routes than AODV in a dense MANET with high node motion rates. This research validated that the VNLayer approach makes software development for MANET easier and improves the performance of MANET protocols.
1‐Deaza‐5′‐noraisteromycin

(+/-)-1-Deazaaristeromycin (4) has been reported to be an inactivator of S-adenosylhomocysteine (AdoHcy) hydrolase and, as a consequence, to affect S-adenosylmethionine (AdoMet) mediated macromolecular biomethylations. To extend this to our program focused on 5'-noraristeromycin derivatives as inhibitors of the same hydrolase enzyme as potential antiviral agents, both enantiomers of 1-deaza-5'-noraristeromycin (5 and 20) have been prepared. Compounds 5 and 20 were evaluated against the following viruses: vaccinia, cowpox, monkeypox, Ebola, herpes simplex type 1 and 2, human cytomegalovirus, Epstein Barr, varicella zoster, hepatitis B, hepatitis C, HIV-1 and HIV-2, adenovirus type 1, measles, Pichinde, parainfluenza type 3, influenza A (H1N1 and H3N2), influenza B, Venezuelan equine encephalitis, rhinovirus type 2, respiratory syncytial, yellow fever, and West Nile. No activity was found nor was there any cytotoxicity to the viral host cells.
The Behavior of Arcing Faults in Low-Voltage Switchboards

An arc fault is the discharge of electricity through the air between two conductors creating large quantities of heat and light. It is widely accepted that there are many variables which affect the behavior of an arc in real switchboards, and thus, understanding the phenomena is difficult. This paper is based upon the results of several years of arc testing with circuits from 155 Vdc to three-phase 450 Vac and at power levels from tens of kilowatts to several megawatts. The goals of the testing were to understand the general behavior of arcing faults in low-voltage switchboards-well enough to predict the motion of arcs-and to design electronic monitoring systems that are capable of protecting switchboards against arcs. This paper will focus on the arc behavior, whereas our other papers will discuss its implications upon forensic investigations and upon the arc-fault protective systems.
Analytical approximations for the critical stock prices of American options: a performance comparison

Many efficient and accurate analytical methods for pricing American options now exist. However, while they can produce accurate option prices, they often do not give accurate critical stock prices. In this paper, we propose two new analytical approximations for American options based on the quadratic approximation. We compare our methods with existing analytical methods including the quadratic approximations in Barone-Adesi and Whaley (J Finance 42:301–320, 1987) and Barone-Adesi and Elliott (Stoch Anal Appl 9(2):115–131, 1991), the lower bound approximation in Broadie and Detemple (Rev Financial Stud 9:1211–1250, 1996), the tangent approximation in Bunch and Johnson (J Finance 55(5):2333–2356, 2000), the Laplace inversion method in Zhu (Int J Theor Appl Finance 9(7):1141–1177, 2006b), and the interpolation method in Li (Working paper, 2008). Both of our methods give much more accurate critical stock prices than all the existing methods above.
How To Elect a Leader Faster than a Tournament

The problem of electing a leader from among n contenders is one of the fundamental questions in distributed computing. In its simplest formulation, the task is as follows: given n processors, all participants must eventually return a win or lose indication, such that a single contender may win. Despite a considerable amount of work on leader election, the following question is still open: can we elect a leader in an asynchronous fault-prone system faster than just running a Θ(log n)-time tournament, against a strong adaptive adversary?In this paper, we answer this question in the affirmative, improving on a decades-old upper bound. We introduce two new algorithmic ideas to reduce the time complexity of electing a leader to O( log* n), using O(n2) point-to-point messages. A non-trivial application of our algorithm is a new upper bound for the tight renaming problem, assigning n items to the n participants in expected O(log2 n ) time and O(n2) messages. We complement our results with lower bound of Ω(n2) messages for solving these two problems, closing the question of their message complexity.
Nonlinear screening and percolative transition in a two-dimensional electron liquid

A variational method is proposed for calculating the percolation threshold, the real-space structure, and the ground-state energy of a disordered two-dimensional electron liquid. Its high accuracy is verified against exact asymptotics and prior numerical results. The inverse thermodynamical density of states is shown to have a strongly asymmetric minimum at a density that is approximately the triple of the percolation threshold. This implies that the experimentally observed metal-insulator transition takes place well before the percolation point is reached.
Explicit Expanders with Cutoff Phenomena

The cutoff phenomenon describes a sharp transition in the convergence of an ergodic finite Markov chain to equilibrium. Of particular interest is understanding this convergence for the simple random walk on a bounded-degree expander graph. The first example of a family of bounded-degree graphs where the random walk exhibits cutoff in total-variation was provided only very recently, when the authors showed this for a typical random regular graph. However, no example was known for an explicit (deterministic) family of expanders with this phenomenon. Here we construct a family of cubic expanders where the random walk from a worst case initial position exhibits total-variation cutoff. Variants of this construction give cubic expanders without cutoff, as well as cubic graphs with cutoff at any prescribed time-point.
The interstellar medium of our Galaxy

Over the past century our picture of diffuse material in space has grown from a simple model of isolated clouds in thermal equilibrium with stellar radiation fields to one of a richly varied composite of materials with a wide range of physical properties and morphologies. The Solar System interacts with a dynamical interstellar medium. Optical, radio, and UV astronomy allow us to study the clouds which form the galactic environment of the Sun. The composition and distribution of interstellar clouds in the disk and halo tell us about the history of elemental formation in our galaxy, and the past and future environment of the Solar System.
Open-Economy Macroeconomics: Developments in Theory and Policy

This paper views developments in open-economy macroeconomics through the lens of the debate over European monetary unification. The empirical tendency for nominal exchange rate regimes to affect the variability of nominal and real exchange rates alike can be rationalized by sticky-price theories or models of asset-market liquidity effects. But plausible liquidity models have difficulty generating enough persistence to match the data. Thus, the macroeconomic stabilization costs of forgoing the exchange-rate realignment option seem pertinent. It is argued that our theories of efficiencies due to a common currency remain unsatisfactory, despite recent advances. The paper concludes by reviewing theories of currency crisis
Utility of daily vs. monthly large-scale climate data: an intercomparison of two statistical downscaling methods

Downscaling of climate model data is essential to local and regional impact analysis. We compare two meth- ods of statistical downscaling to produce continuous, grid- ded time series of precipitation and surface air temperature at a 1/8-degree (approximately 140 km 2 per grid cell) reso- lution over the western U.S. We use NCEP/NCAR Reanaly- sis data from 1950-1999 as a surrogate General Circulation Model (GCM). The two methods included are constructed analogues (CA) and a bias correction and spatial downscal- ing (BCSD), both of which have been shown to be skillful in different settings, and BCSD has been used extensively in hydrologic impact analysis. Both methods use the coarse scale Reanalysis fields of precipitation and temperature as predictors of the corresponding fine scale fields. CA down- scales daily large-scale data directly and BCSD downscales monthly data, with a random resampling technique to gener- ate daily values. The methods produce generally comparable skill in producing downscaled, gridded fields of precipita- tion and temperatures at a monthly and seasonal level. For daily precipitation, both methods exhibit limited skill in re- producing both observed wet and dry extremes and the dif- ference between the methods is not significant, reflecting the general low skill in daily precipitation variability in the re- analysis data. For low temperature extremes, the CA method produces greater downscaling skill than BCSD for fall and winter seasons. For high temperature extremes, CA demon- strates higher skill than BCSD in summer. We find that the choice of most appropriate downscaling technique depends on the variables, seasons, and regions of interest, on the availability of daily data, and whether the day to day cor- respondence of weather from the GCM needs to be repro-
Engineering of bacterial phytochromes for near-infrared imaging, sensing, and light-control in mammals

Near-infrared light is favourable for imaging in mammalian tissues due to low absorbance of hemoglobin, melanin, and water. Therefore, fluorescent proteins, biosensors and optogenetic constructs for optimal imaging, optical readout and light manipulation in mammals should have fluorescence and action spectra within the near-infrared window. Interestingly, natural Bacterial Phytochrome Photoreceptors (BphPs) utilize the low molecular weight biliverdin, found in most mammalian tissues, as a photoreactive chromophore. Due to their near-infrared absorbance BphPs are preferred templates for designing optical molecular tools for applications in mammals. Moreover, BphPs spectrally complement existing genetically-encoded probes. Several BphPs were already developed into the near-infrared fluorescent variants. Based on the analysis of the photochemistry and structure of BphPs we suggest a variety of possible BphP-based fluorescent proteins, biosensors, and optogenetic tools. Putative design strategies and experimental considerations for such probes are discussed.
Transverse and longitudinal coupled bunch instabilities in trains of closely spaced bunches

It is noted that damping rings for the next generation of linear collider may need to contain several bunch trains within which the bunches are quite closely spaced (1 or 2 RF wavelengths). Methods are presented for studying the transverse and longitudinal coupled bunch instabilities applicable to this problem and to other cases in which the placement of the bunches is not necessarily symmetric. It is shown that, given the coherent frequencies and normal modes, the Laplace transform can be used to obtain the motion of the bunches, taking the initial conditions correctly into account. A computer tracking method has been used in the transverse case to obtain the offset of each bunch as a function of time. It is pointed out that at least one of these methods is always applicable, and in many cases both of them are. >
Factors associated with the quality before freezing and after thawing of sperm obtained by microsurgical epididymal aspiration

Objective: To identify whether the cause, site of ductal obstruction, and characteristics of fluid aspirates are associated with the cryosurvival and fertility after thawing of sperm obtained during reconstruction of the excurrent ducts with microsurgical epididymal sperm aspiration, vasal sperm aspiration, or both. Design: Prospective study. Setting: Andrology center at a tertiary care institution. Patient(s): Men undergoing reconstruction of the excurrent duct and sperm aspiration (n = 42) or microsurgical epididymal sperm aspiration (n = 11). Intervention(s): Sperm were tested for an association with the cause and site of obstruction. Fertilization and pregnancy rates after sperm aspiration and intracytoplasmic sperm injection (ICSI) were evaluated for fresh and frozen aspirates. Main Outcome Measure(s): Motile sperm count and percentage motility after thawing. Result(s): The motile sperm count before freezing was significantly higher in the caput epididymis than in the corpus. The motile sperm count before freezing was related inversely to the distance from the caput where the sperm were aspirated. Sperm from clear and opaque fluid aspirates had better percent motility than those from cloudy and creamy fluid aspirates. High fertilization and pregnancy rates were achieved using both fresh and frozen epididymal sperm. Conclusion(s): None of the factors studied was associated with cryosurvival of aspirated epididymal or vasal spermatozoa. Because motility is low after thawing, these specimens are best used with ICSI. (Fertil Steril 1997;68:626-31 Copyright © 1997 American Society for Reproductive Medicine.)
Agroindustrialization, globalization, and international development An overview of issues, patterns, and determinants

This paper offers an overview for a special issue on agroindustrialization, globalization, and international development. It sets out a conceptual framework for understanding the links among these three broad phenomena and then discusses emerging issues and evidence concerning the factors conditioning agroindustrialization in developing countries and the subsequent effects on employment, poverty, and the natural environment. We conclude with a research agenda.