cssi/SciSciGPT-SciSciNet huggingface dataset:
Imbeddings of free actions on handlebodies

Fix a free, orientation-preserving action of a finite group G on a 3-dimensional handlebody V. Whenever G acts freely preserving orientation on a connected 3-manifold X, there is a G-equivariant imbedding of V into X. There are choices of X closed and Seifert-fibered for which the image of V is a handlebody of a Heegaard splitting of X. Provided that the genus of V is at least 2, there are similar choices with X closed and hyperbolic.
Optimizing Ad Allocation in Social Advertising

Social advertising (or social promotion) is an effective approach that produces a significant cascade of adoption through influence in the online social networks. The goal of this work is to optimize the ad allocation from the platform's perspective. On the one hand, the platform would like to maximize revenue earned from each advertiser by exposing their ads to as many people as possible, on the other hand, the platform wants to reduce free-riding to ensure the truthfulness of the advertiser. To this end, we introduce a utility function that can access the above tradeoff. Based on this utility function, we define and study two social advertising problems: budgeted social advertising problem and unconstrained social advertising problem. In the first problem, we aim at selecting a set of seeds for each advertiser that maximizes the utility while setting budget constraints on the attention cost; in the second problem, we propose to optimize a linear combination of the utility and attention costs. We prove that both problems are NP-hard, and then develop constant factor approximation algorithms for both problems.
Collision-Induced Dissociation Mass Spectrometry: A Powerful Tool for Natural Product Structure Elucidation

Mass spectrometry is a powerful tool in natural product structure elucidation, but our ability to directly correlate fragmentation spectra to these structures lags far behind similar efforts in pep...
Integrating Seasonal Forecasts and Insurance for Adaptation among Subsistence Farmers : The Case of Malawi

Climate variability poses a severe threat to subsistence farmers in southern Africa. Two different approaches have emerged in recent years to address these threats: the use of seasonal precipitation forecasts for risk reduction (for example, choosing seed varieties that can perform well for expected rainfall conditions), and the use of innovative financial instruments for risk sharing (for example, index-based weather insurance bundled to microcredit for agricultural inputs). So far these two approaches have remained entirely separated. This paper explores the integration of seasonal forecasts into an ongoing pilot insurance scheme for smallholder farmers in Malawi. The authors propose a model that adjusts the amount of high-yield agricultural inputs given to farmers to favorable or unfavorable rainfall conditions expected for the season. Simulation results - combining climatic, agricultural, and financial models - indicate that this approach substantially increases production in La Nina years (when droughts are very unlikely for the study area), and reduces losses in El Nino years (when insufficient rainfall often damages crops). Cumulative gross revenues are more than twice as large for the proposed scheme, given modeling assumptions. The resulting accumulation of wealth can reduce long-term vulnerability to drought for participating farmers. Conclusions highlight the potential of this approach for adaptation to climate variability and change in southern Africa.
An Exploration of the Link between Development, Economic Growth,and Natural Risk

This paper investigates the link between development, economic growth, and the economic losses from natural disasters in a general analytical framework, with an illustration on hurricane flood risks in New Orleans. It concludes that, where capital accumulates through increased density of capital at risk in a given area, (i) the probability of disaster occurrence decreases with income; (ii) capital at risk  and thus economic losses in case of disaster -- increases faster than economic growth; (iii) increasing risk-taking reinforces economic growth. Economic growth and improved protection transfer risks from frequent low-intensity events to rarer high-impact events. In this context, average annual losses from disasters grow with income, and they grow faster than income at low levels of development and slower than income at high levels of development. These findings are robust to a broad range of modeling choices and parameter values, to the inclusion of risk aversion, and to variations in the decision-making framework (including the introduction of prospect theory's decision weights, biases in risk perception and myopic expectations). They show that risk-taking is both a driver and a consequence of economic development, that risk taking should not be indiscriminately suppressed, and that the world is very likely to experience fewer but more costly disasters in the future.
Advancing in situ modeling of ICMEs: New techniques for new observations

[1] It is generally known that multispacecraft observations of interplanetary coronal mass ejections (ICMEs) are more likely to reveal their three-dimensional structure than single-spacecraft observations. The launch of STEREO in October 2006 has greatly increased the number of multipoint ICME studies, but the field is still in its infancy. To date, many studies still use flux rope models that rely on single track observations through a vast, multifaceted structure, which oversimplifies the problem and hinders interpretation of the large-scale geometry. This oversimplification is especially problematic for multispacecraft ICME observations in which only one spacecraft observes a flux rope structure. To tackle these complex problems, we describe two new techniques and combine them to analyze two ICMEs observed at the twin STEREO spacecraft on 22–23 May 2007, when the spacecraft were separated by ∼ 9∘. We find a combination of non–force-free flux rope multispacecraft modeling, together with a new non–flux rope ICME plasma flow deflection model, better constrains the large-scale structure of these ICMEs. We also introduce a new spatial mapping technique that allows us to put multispacecraft observations and the new ICME model results in context with the convecting solar wind. What is distinctly different about this analysis is that it reveals aspects of ICME geometry and dynamics in a far more visually intuitive way than previously accomplished. In the case of the 22–23 May ICMEs, the analysis facilitates a more physical understanding of ICME large-scale structure, the location and geometry of flux rope substructures within these ICMEs, and their dynamic interaction with the ambient solar wind.
Can Crop Purchase Programs Reduce Poverty and Improve Welfare in Rural Communities? Evidence from the Food Reserve Agency in Zambia

The last decade has seen a resurgence of parastatal crop marketing institutions in sub-Saharan Africa, many of which cite improving food security and incomes as key goals. However, there is limited empirical evidence on the welfare effects of these programs. This article considers one such program, the Zambian Food Reserve Agency (FRA), which purchases maize from smallholder farmers at a pan-territorial price that typically exceeds maize market prices in surplus production areas. Using both fixed effects and an instrumental variables approach combined with correlated random effects, we estimate the effects of the FRA's maize marketing activities on smallholder farm household welfare. Results suggest that FRA activities have positive direct welfare effects on the small minority of smallholder households that are able to sell to it. However, the results also suggest negative indirect FRA effects, as higher levels of FRA activity in a district are associated with higher levels of poverty.
Keynote lecture 2: program analysis and optimization for multi-core computing

As multi-core architectures become ubiquitous in modern computing, large scale scientific applications have to be redesigned to efficiently use the multiple cores and deliver higher performance. One major approach is the automatic detection of parallelism, in which existing conventional sequential programs are translated into parallel programs by optimizing compilers, in order to take advantage of the multiple processors. Optimizing compilers rely upon program analysis techniques to detect data dependences between program statements, perform optimizations, and identify code fragments that can be executed in parallel. In this work we study various program analysis and optimization techniques for multi-core computing and measure their impact in practice. We perform an experimental evaluation of several data dependence tests and program analysis techniques and we compare them in terms of data dependence accuracy, compilation efficiency, effectiveness in parallelization and program execution performance. We run various experiments using the Perfect Club Benchmarks, the SPEC benchmarks, and the scientific library Lapack. We present the measured accuracy of each data dependence test and explain the reasons for inaccuracies. We compare these tests in terms of efficiency and we analyze the tradeoffs between accuracy and efficiency. We also determine the impact of each data dependence test on the total compilation time. Finally, we measure the number of loops parallelized by each test and we compare the execution performance of each benchmark on a multicore architecture.
DynaSpeak: SRI's scalable speech recognizer for embedded and mobile systems

We introduce SRI's new speech recognition engine, DynaSpeak™, which is characterized by its scalability and flexibility, high recognition accuracy, memory and speed efficiency, adaptation capability, efficient grammar optimization, support for natural language parsing functionality, and operation based on integer arithmetic. These features are designed to address the needs of the fast-developing and changing domain of embedded and mobile computing platforms.
Dynamics of Jupiter’s Atmosphere

Results from the Galileo probe and orbiter are compared with Voyager and ground-based results. The probe made measurements to the 20-bar level, well below the nominal cloud base at 5 bars and well below the level where sunlight is absorbed. The winds increased with depth within the clouds and then remained constant below cloud base. This rules out most “thin weather layer” models of Jovian meteorology. Water, H2S, and NH3 were depleted relative to “solar” abundances at the nominal cloud base but increased with depth below 10 bars. Apparently the probe entered a dry downdraft that penetrated to 20 bars. Consistent with this result, the orbiter found water varying by factors of 100 from place to place, with the lowest values at the sites that resemble the one where the probe went in. The orbiter also revealed that these sites are regions of horizontal convergence of the cloud top winds, which is consistent with the downdraft hypothesis.
Review of Diesel Emissions and Control

AbstractThis summary covers key and representative developments in diesel emissions regulations, engine developments, and nitrogen oxide (NOx), particulate matter (PM), and hydrocarbon (HC) remedia...
Late alluvial fan formation in southern Margaritifer Terra, Mars

[1] Crater statistics indicate alluvial fans, crater floor, and fill/mantling deposits within impact craters >50 km in diameter in southern Margaritifer Terra were likely emplaced during multiple epochs: fans formed during the Amazonian or near the Amazonian-Hesperian boundary, crater floor deposits are likely Hesperian in age, and most fill/mantling deposits are Amazonian. The regional distribution of fans points to a late period of widespread water-driven degradation. Two of the final candidate landing sites for the 2011 Mars Science Laboratory mission would land on or near some of these fans, which appear younger than previously considered.
Cosmology and extra dimensions.

In the past few years the search for a consistent quantum theory of gravity and the quest for a unification of gravity with other forces have led to a great deal of interest in theories with extra spatial dimensions. These extra spatial dimensions are unseen because they are compact and small, presumably with typical dimensions of the Planck length, l Pl = 1.616 × 10-33cm. If the “internal” dimensions are static and small compared to the large “external” dimensions the only role they would play in the dynamics of the expansion of the Universe is in determining the structure of the physical laws. However, if the big bang is extrapolated back to the Planck time, then the characteristic size of both internal and external dimensions were the same, and the internal dimensions may have had a more direct role in the dynamics of the evolution of the Universe. This chapter presents some speculations about the role of extra dimensions in cosmology.
Tail Risk Premia and Return Predictability

Abstract The variance risk premium, defined as the difference between the actual and risk-neutral expectations of the forward aggregate market variation, helps predict future market returns. Relying on a new essentially model-free estimation procedure, we show that much of this predictability may be attributed to time variation in the part of the variance risk premium associated with the special compensation demanded by investors for bearing jump tail risk, consistent with the idea that market fears play an important role in understanding the return predictability.
Selective Incorporation of Fluorine in Pyrazoles

Pyrazoles are highly essential heterocyclic structures prevalent in biologically active products used widely throughout various disciplines of chemical industry-including medicine and agriculture. The efficacy of these pyrazole species is enhanced through the introduction of fluorine and corresponding functionalities; therefore, synthetic methods for the fluorination of these structures is highly appealing which follows the overall trend of increasing interest in fluorination chemistry. Toward assimilating the known techniques for fluorine incorporation to the pyrazole heterocyclic structure we have reviewed both the new and traditional synthetic approaches to the assembly of functionalized pyrazole derivatives. Specifically, efficient synthetic methods and regioselective incorporation of fluorine and fluorine containing functional groups into different pyrazole ring systems are examined.
Lessons from China for Africa

China has been the most successful developing country in this modern era of globalization. Since initiating economic reform after 1978, its economy has expanded at a steady rate over 8 percent per capita, fueling historically unprecedented poverty reduction (the poverty rate declined from over 60 percent to 7 percent in 2007). Other developing countries struggling to grow and reduce poverty are naturally interested in what has been the source of this impressive growth and what, if any, lessons they can take from China. This paper focuses on four features of modern China that have changed significantly between the pre-reform period and today. The Chinese themselves call their reform program Gai Ge Kai Feng, "change the system, open the door." "Change the system" means altering incentives and ownership, that is, shifting the economy from near total state ownership to one in which private enterprise is dominant. "Open the door" means exactly what it says, liberalizing trade and direct investment. A third lesson is the development of high-quality infrastructure: China's good roads, reliable power, world-class ports, and excellent cell phone coverage throughout the country are apparent to any visitor. What is less well known is that most of this infrastructure has been developed through a policy of "cost recovery" that prices infrastructure services at levels sufficient to finance the capital cost as well as operations and maintenance. A fourth important lesson is China's careful attention to agriculture and rural development, complemented by rural-urban migration.
Tensor methods for large sparse systems of nonlinear equations

This paper introduces tensor methods for solving large sparse systems of nonlinear equations. Tensor methods for nonlinear equations were developed in the context of solving small to medium-sized dense problems. They base each iteration on a quadratic model of the nonlinear equations, where the second-order term is selected so that the model requires no more derivative or function information per iteration than standard linear model-based methods, and hardly more storage or arithmetic operations per iteration. Computational experiments on small to medium-sized problems have shown tensor methods to be considerably more efficient than standard Newton-based methods, with a particularly large advantage on singular problems. This paper considers the extension of this approach to solve large sparse problems. The key issue considered is how to make efficient use of sparsity in forming and solving the tensor model problem at each iteration. Accomplishing this turns out to require an entirely new way of solving the tensor model that successfully exploits the sparsity of the Jacobian, whether the Jacobian is nonsingular or singular. We develop such an approach and, based upon it, an efficient tensor method for solving large sparse systems of nonlinear equations. Test results indicate that this tensor method is significantly more efficient and robust than an efficient sparse Newton-based method, in terms of iterations, function evaluations, and execution time. © 1998 The Mathematical Programming Society, Inc. Published by Elsevier Science B.V.
Dynamic pricing of power in Smart-Grid networks

In this paper we introduce the problem of dynamic pricing of power for smart-grid networks. We consider a network utility maximization (NUM) framework in a deterministic setting with a single provider, multiple users and a finite horizon. The provider produces power or buys power in a (deterministic) spot market, and determines a dynamic price to charge the users. The users then adjust their demand in response to the time-varying prices. This is typically categorized as the problem of demand response, and we study a progression of related models by focusing on the characterization of the structure of the optimal dynamic prices in the Smart Grid and the optimal demand and supply under various interaction with a spot market.
Testing for nonlinearity using redundancies: quantitative and qualitative aspects

Abstract A method for testing nonlinearity in time series is described based on information-theoretic functionals-redundancies, linear and nonlinear forms of which allow either qualitative, or, after incorporating the surrogate data technique, quantitative evaluation of dynamical properties of scrutinized data. An interplay of quantitative and qualitative testing on both the linear and nonlinear levels is analyzed and robustness of this combined approach against spurious nonlinearity detection is demonstrated. Evaluation of redundancies and redundancy-based statistics as functions of time lag and embedding dimension can further enhance insight into dynamics of a system under study.
Cosmological Production of Superheavy Magnetic Monopoles

Grand unified models of elementary particle interactions contain stable superheavy magnetic monopoles. The density of such monopoles in the early universe is estimated to be unacceptably large. Cosmological monopole production may be suppressed if the phase transition at the grand unification mass scale is strongly first order.
Tree-size bounded alternation

The size of an accepting computation tree of an alternating Turing machine (ATM) is introduced as a complexity measure. We present a number of applications of tree-size to the study of more traditional complexity classes. Tree-size on ATMs is shown to closely correspond to time on nondeterministic TMs and on nondeterministic auxiliary pushdown automata. One application of the later is a useful new characterization of the class of languages log-space-reducible to context-free languages. Surprising relationships with parallel-time complexity are also demonstrated. ATM computations using at most space S(n) and tree-size Z(n) (simultaneously) can be simulated in alternating space S(n) and time S(n) · log Z(n) (simultaneously). Several well-known simulations, e.g., Savitch's theorem, are special cases of this result. It also leads to improved parallel complexity bounds for many problems in terms of both time and number of “processors.” As one example we show that context-free language recognition in time O(log2 n) is possible on several parallel models. Further, this bound is achievable with only a polynomial number of processors, in contrast to all previously known sub-linear time CFL recognizers.
An Improved System for the Palladium-Catalyzed Borylation of Aryl Halides with Pinacol Borane

A highly efficient method for the palladium-catalyzed borylation of aryl halides with an inexpensive and atom-economical boron source, pinacol borane, has been developed. This system allows for the conversion of aryl and heteroaryl iodides, bromides, and several chlorides, containing a variety of functional groups, to the corresponding pinacol boronate esters. In addition to the increase in substrate scope, this is the first general method where relatively low quantities of catalyst and short reaction times can be employed.
Comprehension Tools for Teachers: Reading for Understanding from Prekindergarten Through Fourth Grade

This paper describes the theoretical framework, as well as the development and testing of the intervention, Comprehension Tools for Teachers (CTT), which is composed of eight component interventions targeting malleable language and reading comprehension skills that emerging research indicates contribute to proficient reading for understanding for prekindergarteners through fourth graders. Component interventions target processes considered largely automatic as well as more reflective processes, with interacting and reciprocal effects. Specifically, we present component interventions targeting cognitive, linguistic, and text-specific processes, including morphological awareness, syntax, mental-state verbs, comprehension monitoring, narrative and expository text structure, enacted comprehension, academic knowledge, and reading to learn from informational text. Our aim was to develop a tool set composed of intensive meaningful individualized small group interventions. We improved feasibility in regular classrooms through the use of design-based iterative research methods including careful lesson planning, targeted scripting, pre- and postintervention proximal assessments, and technology. In addition to the overall framework, we discuss seven of the component interventions and general results of design and efficacy studies.
A critical evaluation of NOx modeling in a model combustor

Reliable NO x modeling depends on the accurate prediction of both velocity and temperature fields. The velocity and temperature fields of a propane diffusion flame combustor, with interior and exterior conjugate heat transfers, were first numerically studied. The results from three combustion models, together with the renormalization group (RNG) k - e turbulence model and the discrete ordinates radiation model are discussed, and compared with comprehensive experimental measurements. The flow patterns and the recirculation zone length in the combustion chamber are excellently predicted, and the mean axial velocities are in fairly good agreement with the experimental data for all three combustion models. The mean temperature profiles are fairly well captured by the probability density function (PDF) and eddy dissipation (EDS) combustion models. However, the EDS-finite-rate combustion model fails to provide an acceptable temperature field. Based on the acceptable velocity and temperature fields, a number of NO modeling approaches were evaluated in a postprocessing mode. The partial-equilibrium approach of O and OH radical concentrations shows a significant effect on the thermal NO formation rate. In contrast, the prompt NO, the NO reburn mechanism and the third reaction of the extended Zeldovich mechanism have negligible effects on the overall NO formation in the present study. This study indicates that the semiempirical, postprocessing NO model can provide valuable NO simulations as long as the velocity and temperature fields are adequately predicted.
A Cartesian grid embedded boundary method for the heat equation and Poisson's equation in three dimensions

We present an algorithm for solving Poisson's equation and the heat equation on irregular domains in three dimensions. Our work uses the Cartesian grid embedded boundary algorithm for 2D problems of Johansen and Colella [A Cartesian grid embedded boundary method for Poisson's equation on irregular domains, J. Comput. Phys. 147(2) (1998) 60-85] and extends work of McCorquodale, Colella and Johansen [A Cartesian grid embedded boundary method for the heat equation on irregular domains, J. Comput. Phys. 173 (2001) 620-635]. Our method is based on a finite-volume discretization of the operator, on the control volumes formed by intersecting the Cartesian grid cells with the domain, combined with a second-order accurate discretization of the fluxes. The resulting method provides uniformly second-order accurate solutions and gradients and is amenable to geometric multigrid solvers.
The structure and governance of venture-capital organizations

Abstract Venture-capital organizations raise money from individuals and institutions for investment in early-stage businesses that offer high potential but high risk. This paper describes and analyzes the structure of venture-capital organizations, focusing on the relationship between investors and venture capitalists and between venture-capital firms and the ventures in which they invest. The agency problems in these organizations and to the contracts and operating procedures that have evolved in response are emphasized. Venture-capital organizations are contrasted with large, publicly traded corporations and with leveraged buyout organizations.
Efficient Irregular Wavefront Propagation Algorithms on Hybrid CPU-GPU Machines

We address the problem of efficient execution of a computation pattern, referred to here as the irregular wavefront propagation pattern (IWPP), on hybrid systems with multiple CPUs and GPUs. The IWPP is common in several image processing operations. In the IWPP, data elements in the wavefront propagate waves to their neighboring elements on a grid if a propagation condition is satisfied. Elements receiving the propagated waves become part of the wavefront. This pattern results in irregular data accesses and computations. We develop and evaluate strategies for efficient computation and propagation of wavefronts using a multi-level queue structure. This queue structure improves the utilization of fast memories in a GPU and reduces synchronization overheads. We also develop a tile-based parallelization strategy to support execution on multiple CPUs and GPUs. We evaluate our approaches on a state-of-the-art GPU accelerated machine (equipped with 3 GPUs and 2 multicore CPUs) using the IWPP implementations of two widely used image processing operations: morphological reconstruction and euclidean distance transform. Our results show significant performance improvements on GPUs. The use of multiple CPUs and GPUs cooperatively attains speedups of 50× and 85× with respect to single core CPU executions for morphological reconstruction and euclidean distance transform, respectively.
The “hateful” patient

Successful patient–physician interactions are paramount to effective patient care. Difficult patients may be nocuous to themselves and to the care of other patients, as they disrupt the function of the medical team. This article illustrates the diagnosis and the management of the “hateful patient” using a case report. The hateful patient was described as “the name doctors dread to have in their daily roster on in the list of patients to call back.” The patient described in the report fulfilled three of the four profile of the hateful patient: dependent clinger, entitled demander, and manipulative help rejecter. The case study highlights the opportunity represented by the management of the hateful patients and the psychodynamic interactions with such patients.
THE CONDENSED MATTER PHYSICS OF PLANETARY INTERIORS

The deep interiors of Jupiter and Saturn consist of fluid, metallic hydrogen. In Jupiter the metallic hydrogen is uniformly mixed with helium. In Saturn, the incomplete solubility of helium may cause unmixing and energy release. In the interiors of Uranus and Neptune the fluid mixture (of hydrogen, helium, water, methane and ammonia) is metallic or ionic. The terrestral planetary cores are predominantly metallic iron.
Spin-dependent exciton formation rates in π-conjugated oligomers and polymers

Abstract We have measured the ratio, r = σ S / σ T of the formation cross section, of singlet (S) and triplet (T) excitons from polarons in π -conjugated oligomer and polymer films, using a spectroscopic/magnetic resonance technique. We show that exciton formation from separated polaron pairs in π -conjugated compounds is spin-dependent, specifically r >1. Moreover, we discovered a universal relation between r and the conjugation length (CL): namely r −1 α (CL) −1 .
A Pro-Poor Growth Strategy to End Hunger

Over 800 million people in the world are chronically undernourished and food insecure and some 1.2 billion live on the equivalent of less than one U.S. dollar per day (Food and Agricultural Organization, World Bank 2001). Those persistently hungry do not get enough to eat on a daily basis to lead active, healthy lives. They are hungry predominantly because they are poor and cannot afford enough food to eat adequately. Hunger affects not just their nutritional status but also the overall quality of their lives. Their lives are shorter and filled
Reliably estimating bare chi from compressible blends in the grand canonical ensemble

Abstract The bare chi characterizing polymer blends plays a significant role in their macroscopic description. Therefore, its experimental determination, especially from small-angle-neutron-scattering experiments on isotopic blends, is of prime importance in thermodynamic investigations. Experimentally extracted quantity, commonly known as the effective chi is affected by thermodynamics, in particular by polymer connectivity, and composition and density fluctuations. The present work is primarily concerned with studying four possible effective chis, one of which is closely related to the conventionally defined effective chi, to see which one plays the role of a reliable estimator of the bare chi. We show that the conventionally extracted effective chi is not a good measure of the bare chi in most blends. A related quantity that does not contain any density fluctuations, and one which can be easily extracted, is a good estimator of the bare chi in all blends except weakly interacting asymmetric blends (see text for definition). The density fluctuation contribution is given by ( Δ v ¯ ) 2 / 2 TK T , where Δ v ¯ is the difference of the partial monomer volumes and KT is the compressibility. Our effective chis are theory-independent. From our calculations and by explicitly treating experimental data, we show that the effective chis, as defined here, have weak composition dependence and do not diverge in the composition wings. We elucidate the impact of compressibility and interactions on the behavior of the effective chis and their relationship with the bare chi.
Finite Temperature and Large Gauge Invariance

In this talk, I will sumarize the status of our understanding of the puzzle of large gauge invariance at finite temperature.
Symmetric signaling by an asymmetric 1 erythropoietin : 2 erythropoietin receptor complex

Via sites 1 and 2, erythropoietin binds asymmetrically to two identical receptor monomers, although it is unclear how asymmetry affects receptor activation and signaling. Here we report the design and validation of two mutant erythropoietin receptors that probe the role of individual members of the receptor dimer by selectively binding either site 1 or site 2 on erythropoietin. Ba/F3 cells expressing either mutant receptor do not respond to erythropoietin, but cells co-expressing both receptors respond to erythropoietin by proliferation and activation of the JAK2-Stat5 pathway. A truncated receptor with only one cytosolic tyrosine (Y343) is sufficient for signaling in response to erythropoietin, regardless of the monomer on which it is located. Similarly, only one receptor in the dimer needs a juxtamembrane hydrophobic L253 or W258 residue, essential for JAK2 activation. We conclude that despite asymmetry in the ligand-receptor interaction, both sides are competent for signaling, and appear to signal equally.
On the role of macromolecular configuration in rapid coal devolatilization

Abstract The role of macromolecular configuration in rapid coal devolatilization is investigated with two reaction models which differ only in their means to relate intermediates and reactant species. The conventional model invokes stoichiometric coefficients, while the depolymerization model invokes probability expressions which depend on the extents of pyrolytic degradation and char formation. For each model, correlations of transient weight loss data, parametric sensitivities, and extrapolations to pulverized coal combustion conditions are given. These results show that the quantitative impact of macromolecular configuration can be masked by uncertainties in the chemical rate coefficients for the pyrolysis reactions. However, in far-ranging extrapolations, only predictions from the macromolecular depolymerization model compare favourably with the available data. This model also provides a mechanistic basis for yield enhancement by faster heating: namely, the concurrent formation of stable char links, as the coal macromolecule dissociates, inhibits the subsequent formation of tar precursors to an extent which depends on the thermal history.
Relating Boltzmann machines to conventional models of computation

Abstract It is shown that clocked Boltzmann machines are not much more powerful than combinational circuits built from gates which compute Boolean threshold functions and their negations. More formally, any clocked Boltzmann machine can be simulated by a threshold circuit with running time greater by a constant factor and size greater by a polynomial.
College Freshman Attitudes Toward Cheating.

The purpose of this study was to study characteristics of students with lenient attitudes toward cheating and to identify the types of colleges that tend to enroll these students. The student sample consisted of 1500 entering freshmen at 37 colleges, while the analysis by type of institution was conducted with 119 colleges and universities. Students with lenient attitudes toward academic cheating shared similar attitudes about cheating in government and industry. Furthermore, these students, compared to other students, tend to be less academically motivated, have fewer artistic-literary interests, and come from lower socioeconomic backgrounds. Institutions that enrolled students with strong attitudes against cheating, and thus provided less of a climate for cheating, were generally more selective, all-female, and small in size. These same types of institutions, according to previous research, also have lower cheating rates.
Virtual Prototyping Simulation for Design of Mechanical Systems

Developments in simulation technology that enable a qualitatively new virtual prototyping approach to design of mechanical systems are summarized and their integration into an engineering design environment is illustrated. Simulation tools and their enabling technologies are presented in the context of vehicle design, with references to the literature provided. Their implementation for design representation, real-time driver-in-the-loop simulation, dynamic performance simulation, dynamic stress and life prediction, maintainability analysis, design sensitivity analysis, and design optimization is outlined. A testbed comprised of computer aided engineering tools and a design level of fidelity driving simulator that has been developed to demonstrate the feasibility of virtual prototyping simulation for mechanical system design is presented. Two 1994 demonstrations of this capability for vehicle design are presented, to illustrate the state of the technology and to identify challenges that remain in making virtual prototyping simulation an integral part of mechanical system design in US industry.
Value-focused assessment of information system security in organizations

Information system (IS) security continues to present a challenge for executives and professionals. A large part of IS security research is technical in nature with limited consideration of people and organizational issues. The study presented in this paper adopts a broader perspective and presents an understand- ing of IS security in terms of the values of people from an organizational perspec- tive. It uses the value-focused thinking approach to identify 'fundamental' objectives for IS security and 'means' of achieving them in an organization. Data for the study were collected through in-depth interviews with 103 managers about their values in managing IS security. Interview results suggest 86 objectives that are essential in managing IS security. The 86 objectives are organized into 25 clus- ters of nine fundamental and 16 means categories. These results are validated by a panel of seven IS security experts. The findings suggest that for maintaining IS security in organizations, it is necessary to go beyond technical considerations and adopt organizationally grounded principles and values.
Monte Carlo simulation of quantum computation

Abstract The many-body dynamics of a quantum computer can be reduced to the time evolution of non-interacting quantum bits in auxiliary fields using the Hubbard–Stratonovich representation of two-bit quantum gates in terms of one-bit gates. This makes it possible to perform the stochastic simulation of a quantum algorithm based on the Monte Carlo evaluation of an integral of dimension polynomial in the number of quantum bits. As an example, the simulation of the quantum circuit for the fast Fourier transform is discussed.
Disambiguation of characters by a second-stage classifier

Certain characters are distinguishable from each other only by fine detail, and, therefore, in our method we group those characters into hierarchical categories. When the first classifier assigns a character to one of those categories, the second process, which is called disambiguation, is applied. We actually use two types of disambiguators. In one we look at the skeleton graph in finer detail and in the other we look at the original gray scale data. The first disambiguation process is geared toward resolving ties between the top two choices of the first classifier (pair disambiguation). Each procedure uses the skeleton features matched to the prototypes by the first classifier and then takes a closer look at the geometrical relations between arcs and strokes. Error analysis of the results suggested the need for the re- examination of the gray scale data. For this purpose the gray scale values of skeletons are used to find an accurate threshold in order to extract contours. Interpretations whose characteristics do not align well with the features measured from the contours are eliminated progressively. Experiments conducted with this method on address blocks supplied by the USPS indicated that the overall performance was substantially improved.© (1993) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
The observed concentration–mass relation for galaxy clusters

The properties of clusters of galaxies offer key insights into the assembly process of structure in the universe. Numerical simulations of cosmic structure formation in a hierarchical, dark matter dominated universe suggest that galaxy cluster concentrations, which are a measure of a halo's central density, decrease gradually with virial mass. However, cluster observations have yet to confirm this correlation. The slopes of the run of measured concentrations with virial mass are often either steeper or flatter than that predicted by simulations. In this work, we present the most complete sample of observed cluster concentrations and masses yet assembled, including new measurements for 10 strong-lensing clusters, thereby more than doubling the existing number of strong-lensing concentration estimates. We fit a power law to the observed concentrations as a function of virial mass, and find that the slope is consistent with the slopes found in simulations, though our normalization factor is higher. Observed lensing concentrations appear to be systematically larger than X-ray concentrations, a more pronounced effect than that found in simulations. We also find that at a fixed mass, the bulk of observed cluster concentrations are distributed lognormally, with the exception of a few anomalously high concentration clusters. We examine the physical processes likely responsible for the discrepancy between lensing and X-ray concentrations, and for the anomalously high concentrations in particular. The forthcoming Millennium simulation results will offer the most comprehensive comparison set to our findings of an observed concentration-mass power law relation.
Contrast-enhanced ultrasonography for the evaluation of liver fibrosis after biliary obstruction

Contrast-enhanced ultrasonography for the evaluation of liver fibrosis after biliary obstruction
Directional Imbalance of Vestibular Nystagmus in cat Following Repeated Unidirectional Angular Acceleration

Cats were subjected to schedules of angular accelerations to determine if a marked nystagmic habituation to accelerations of one direction would “transfer” and thus cause a reduced nystagmus to acc...
Computed tomographic diagnosis of renal infarction

Two cases of renal infarcts diagnosed on CT scans are presented which demonstrate findings that should be identifiable and diagnostic to indicate renal infarction. The examination is more reliable and specific if it is performed after the administration of intravenous radiographic contrast material. The contrast can be given either by a bolus or an infusion injection. The findings after contrast-enhanced scan should be specific enough to identify the cause of the patient's symptoms. A percutaneous CT guided biopsy can be performed to confirm the diagnosis.
Acylation of oxazoles by the copper-mediated reaction of oxazol-2-ylzinc chloride derivatives

Abstract C-2 acylation of oxazole derivatives is accomplished by reaction of oxazol-2-ylzinc chloride reagents with acid chlorides in the presence of cuprous iodide. O-acylated vinylisonitriles, which are the sole product from the corresponding reaction employing lithiooxazole, are not observed. The method accommodates substituted and unsubstituted oxazoles with a variety of acid chlorides.
Communication-efficient matrix multiplication on hypercubes

In this paper we present an efficient dense matrix multiplication algorithm for distributed memory computers with a hypercube topology. The proposed algorithm performs better than all previously proposed algorithms for a wide range of matrix sizes and number of processors, especially for large matrices. We analyze the performance of the algorithms for two types of hypercube architectures, one in which each node can use (to send and receive) at most one communication link at a time and the other in which each node can use all communication links simultaneously.
Complexity of graph self-assembly in accretive systems and self-destructible systems

Self-assembly is a process in which small objects autonomously associate with each other to form larger complexes. It is ubiquitous in biological constructions at the cellular and molecular scale and has also been identified by nanoscientists as a fundamental method for building nano-scale structures. Recent years have seen convergent interest and efforts in studying self-assembly from mathematicians, computer scientists, physicists, chemists, and biologists. However most complexity theoretical studies of self-assembly utilize mathematical models with two limitations: (1) only attraction, while no repulsion, is studied; (2) only assembled structures of two dimensional square grids are studied. In this paper, we study the complexity of the assemblies resulting from the cooperative effect of repulsion and attraction in a more general setting of graphs. This allows for the study of a more general class of self-assembled structures than the previous tiling model. We define two novel assembly models, namely the accretive graph assembly model and the self-destructible graph assembly model, and identify a fundamental problem in them: the sequential construction of a given graph. We refer to it as the Accretive Graph Assembly Problem (AGAP) and the Self-Destructible Graph Assembly Problem (DGAP), in the respective models. Our main results are: (i) AGAP is NP-complete even if the maximum degree of the graph is restricted to 4 or the graph is restricted to be planar with maximum degree 5; (ii) counting the number of sequential assembly orderings that result in a target graph (#AGAP) is #P-complete; and (iii) DGAP is PSPACE-complete even if the maximum degree of the graph is restricted to 6 (this is the first PSPACE-complete result in self-assembly). We also extend the accretive graph assembly model to a stochastic model, and prove that determining the probability of a given assembly in this model is #P-complete.
Propane hydrogenolysis over supported nickel catalysts: Structural and support effects

Abstract Kinetic data for propane hydrogenolysis were determined for Ni catalysts supported on SiO2, Nb2O5, Nb2O5SiO2, and TiO2. Over a metal particle size range of 2.5–6.0 nm, the activities for three Ni SiO 2 catalysts varied by no more than a factor of 5. The lowest activity was found for a sample which had been reduced under the most severe conditions and believed to have a large proportion of (111) planes. The sample with the smallest particle size showed a higher selectivity. Activities for Ni supported on the other three oxides were lower, indicative of support effects. For samples reduced at 773 K, the suppression in activity varied in the order Nb2O5 > TiO2 ~ Nb2O5 SiO2. The metal-support interactions were reversible by oxidizing the samples and rereducing at a lower temperature. An oxygen treatment at 473 K was sufficient to recover the activity of Ni TiO 2 but not for Ni Nb 2 O 5 , which required an oxygen treatment at 673 K. A model which considers the overall energetics of the regeneration process is presented to explain this difference.
Analysis of protein phosphorylation by mass spectrometry

The reversible phosphorylation of proteins is recognized as an essential post-translational modification regulating cell signaling and ultimately function of biological systems. Detection of phosphopeptides and localization of phosphorylation sites remains quite a challenge, even if the protein is purified to near homogeneity. Mass spectrometry has become a vital technique that is routinely utilized for the identification of proteins from whole cell lysates. Nonetheless, due to the minimal amount of phosphorylation found on proteins, enrichment steps for isolating phosphopeptides from complex mixtures have been the focus of many research groups world-wide. In this review, we describe some current methods for the enrichment of phosphopeptides that are compatible with mass spectrometry for assignment of phosphorylation sites. Phosphorylation modifications on proteins and peptides are either directly isolated by solid-phase approaches or chemically modified for selective isolation and/or improved characterization by mass spectrometry. These strategies hold the potential for rapid and sensitive profiling of phosphoproteins from a variety of sources and cellular conditions.