cssi/SciSciGPT-SciSciNet huggingface dataset:
Bifurcation of Macroeconometric Models and Robustness of Dynamical Inferences

In systems theory, it is well known that the parameter spaces of dynamical systems are stratified into bifurcation regions, with each supporting a different dynamical solution regime. Some can be stable, with different characteristics, such as monotonic stability, periodic damped stability, or multiperiodic damped stability, and some can be unstable, with different characteristics, such as periodic, multiperiodic, or chaotic unstable dynamics. But in general the existence of bifurcation boundaries is normal and should be expected from most dynamical systems, whether linear or nonlinear. Bifurcation boundaries in parameter space are not evidence of model defect. While existence of such bifurcation boundaries is well known in economic theory, econometricians using macroeconometric models rarely take bifurcation into consideration, when producing policy simulations from macroeconometrics models. Such models are routinely simulated only at the point estimates of the models’ parameters. Barnett and He (1999) explored bifurcation stratification of Bergstrom and Wymer’s (1976) continuous time UK macroeconometric model. Bifurcation boundaries intersected the confidence region of the model’s parameter estimates. Since then, Barnett and his coauthors have been conducting similar studies of many other newer macroeconometric models spanning all basic categories of those models. So far, they have not found a single case in which the model’s parameter space was not subject to bifurcation stratification. In most cases, the confidence region of the parameter estimates were intersected by some of those bifurcation boundaries. The most fundamental implication of this research is that policy simulations with macroeconometric models should be conducted at multiple settings of the parameters within the confidence region. While this result would be as expected by systems theorists, the result contradicts the normal procedure in macroeconometrics of conducting policy simulations solely at the point estimates of the parameters. This survey provides an overview of the classes of macroeconometric models for which these experiments have so far been run and emphasizes the implications for lack of robustness of conventional dynamical inferences from macroeconometric policy simulations. By making this detailed survey of past bifurcation experiments available, we hope to encourage and facilitate further research on this problem with other models and to emphasize the need for simulations at various points within the confidence regions of macroeconometric models, rather than at only point estimates.
A powerful post-processing algorithm for time-domain pitch trackers

This paper describes a powerful post-processing algorithm for time-domain pitch trackers. On two successive passes, the post-processing algorithm eliminates errors produced during a first pass by a time-domain pitch tracker. During the second pass, incorrect pitch values are detected as "outliers" by computing the distribution of values over a sliding 80 msec window. During the third pass, remaining pitch pulses are used as anchor points to reconstruct the pitch train from the original waveform. The algorithm produced a decrease in the error rate from 21% obtained with the original time domain pitch tracker to 2% for words and sentences produced in an office environment by 3 male and 3 female talkers. In a noisy computer room errors decreased from 52% to 2.9% for the same stimuli produced by 2 male talkers. The fundamental frequency micro-structure is tracked sufficiently well to be used in extracting phonetic features in a feature-based recognition system.
Unsteady Flow Simulation of High-speed Turbopumps

High fidelity computations were carried out to analyze the orbiter LH2 feedline flowliner. Computations were performed on the Columbia platform which is a 10,240-processor supercluster consisting of 20 Altix nodes with 512 processors each. Various computational models were used to characterize the unsteady flow features in the turbopump, including the orbiter Low-Pressure-Fuel-Turbopump (LPFTP) inducer. Unsteady flow originating from the orbiter LPFTP inducer is one of the major contributors to the high frequency cyclic loading that results in high cycle fatigue damage to the gimbal flowliners just upstream of the LPFTP. An incompressible Navier-Stokes flow solver INS3D, based on the artificial compressibility method, was used to compute the flow of liquid hydrogen in each test article.
Bailouts in a Federation

The recent move towards decentralization in countries such as Spain, Hungary, and South Africa and the difficulties that central governments have had in dealing with fiscal irresponsibility on the part of regional governments in countries such as Argentina, Brazil, and India has made the study of transfer systems one of the most important areas of research in federalism today. A model of a federation is developed in which regional governments act as Nash competitors with each other but are first-movers in a Stackelberg game with the central government. The central government finds that it will maximize its expected votes by increasing transfers as regions borrow. This bail out of regional governments creates a regional soft budget constraint and results in two incentive effects, a common pool effect on tax payments and an opportunity cost effect. The soft budget constraint lowers the opportunity cost of borrowing for the region, but also increases the tax-cost since a portion of the borrowing must be paid for through increased taxes. The common property problem associated with tax payments implies that the increased tax cost must be less than the decrease in the opportunity cost (leading to excessive borrowing) unless the central government increases grants to other regions when it institutes a bailout. Somewhat surprisingly, in the latter case the additional increased taxes may increase costs enough to offset the lower opportunity cost resulting from the bailout, leading to efficient borrowing decisions as in the case of a hard budget constraint. The results are also useful for understanding the empirical estimation of soft budget constraints.
Ecuador's rural nonfarm sector as a route out of poverty

The author analyzes a recent household survey for Ecuador to assess the role of the nonagricultural rural sector in reducing poverty. That sector accounts for roughly 40 percent of rural incomes in Ecuador, three-fourths of which comes from nonagricultural enterprises as opposed to wage labor. The sector provides employment to nearly 40 percent of men and 50 percent of economically active women. The nonagricultural rural sector represents a potentially important route out of poverty: Poverty declines as the share of income from nonagricultural sources arises. Nonagricultural employment and earnings are positively associated with higher education levels and better access to infrastructure services. Although women are more likely than men to be employed in this sector, their earnings for given education levels and other household characteristics are significantly lower. All other things equal, the greatest fall in poverty could be expected from expanding employment opportunities in transport, commerce-related activities, and such services as administration and the hotel and restaurant trade.
The Addition of Phosgene to 2,3-Butanedione: A Facile Synthetic Entry into the 4,5-Dichloro-1,3-dioxolan-2-one Family

Abstract The addition of phosgene to 1,2-Diketones at room temperature constitutes a facile entry into the 1,3-dioxolan-2-one family.
Water Under Extreme Conditions for Green Chemistry

The sections in this article are Introduction Background Properties of HTW Process Engineering Considerations Theoretical, Computational, and Experimental Methods Classical Theory Molecular and Computational Modeling Experimental Methods pH Effects Recent Progress in HTW Synthesis Hydrogenation CC Bond Formation Friedel–Crafts Alkylation Heck Coupling Nazarov Cyclization Condensation Hydrolysis Rearrangements Hydration/Dehydration Elimination Partial Oxidation to Form Carboxylic Acids CC Bond Cleavage H–D Exchange Amidation Acknowledgments Keywords: water; high-temperature water; supercritical water; organic synthesis; green chemistry
Estimating Heterogeneous Choice Models with Stata

When a binary or ordinal regression model incorrectly assumes that error variances are the same for all cases, the standard errors are wrong and (unlike OLS regression) the parameter estimates are biased. Heterogeneous choice/ location-scale models explicitly specify the determinants of heteroskedasticity in an attempt to correct for it. These models are also useful when the variability of underlying attitudes is itself of substantive interest. This paper illustrates how Williams’ user-written routine oglm (Ordinal Generalized Linear Models) can be used to estimate heterogeneous choice and related models. It further shows how two other models that have appeared in the literature – Allison’s (1999) model for comparing logit and probit coefficients across groups, and Hauser and Andrew’s (2006) logistic response model with partial proportionality constraints (LRPPC) – are special cases of the heterogenous choice model and/or algebraically equivalent to it, and can also be estimated with oglm. Other key features of oglm that are illustrated include support for linear constraints, the use of prefix commands such as svy and stepwise, and the computation of predicted probabilities and marginal effects.
Inference in Hybrid Networks: Theoretical Limits and Practical Algorithms

An important subclass of hybrid Bayesian networks are those that represent Conditional Linear Gaussian (CLG) distributions -- a distribution with a multivariate Gaussian component for each instantiation of the discrete variables. In this paper we explore the problem of inference in CLGs, and provide complexity resuits for an important class of CLGs, which includes Switching Kalman Filters. In particular, we prove that even if the CLG is restricted to an extremely simple structure of a polytree, the inference task is NP-hard. Furthermore, we show that, unless P=NP, even approximate inference on these simple networks is intractable. Given the often prohibitive computational cost of even approximate inference, we must take advantage of special domain properties which may enable efficient inference. We concentrate on the fault diagnosis domain, and explore several approximate inference algorithms. These algorithms try to find a small subset of Gaussians which are a good approximation to the full mixture distribution. We consider two Monte Carlo approaches and a novel approach that enumerates mixture components in order of prior probability. We compare these methods on a variety of problems and show that our novel algorithm is very promising for large, hybrid diagnosis problems.
The Parallel Complexity of Deadlock Detection

When serially reusable multiunit resources are shared among many processes, each of which has exclucive control over some resource units, it is possible for deadlocks to happen. The work of Holt, [ Holt, 71b], stated the problem of deadlock detection as a directed multigraph problem. In this paper we examine the possibility of existence of fast parallel algorithms for deadlock detection. Although many graph problems have efficient parallel solutions (in parallel polylogarithic time, by using only a polynomial number of processors), we present strong evidence that this is not the case for the general deadlock detection problem. We show that the problem is complete in P under log-space reductions and thus probably not efficiently parallelizable. Fortunately, when the problem is restricted (e.g. single-unit requests of processes or single-unit resources), then it falls in NC. We present efficient parallel algorithms for the restricted versions of the deadlock detection problem.
Randomization inference for treatment effect variation

Summary Applied researchers are increasingly interested in whether and how treatment effects vary in randomized evaluations, especially variation that is not explained by observed covariates. We propose a model-free approach for testing for the presence of such unexplained variation. To use this randomization-based approach, we must address the fact that the average treatment effect, which is generally the object of interest in randomized experiments, actually acts as a nuisance parameter in this setting. We explore potential solutions and advocate for a method that guarantees valid tests in finite samples despite this nuisance. We also show how this method readily extends to testing for heterogeneity beyond a given model, which can be useful for assessing the sufficiency of a given scientific theory. We finally apply our method to the National Head Start impact study, which is a large-scale randomized evaluation of a Federal preschool programme, finding that there is indeed significant unexplained treatment effect variation.
Dissertations On First Principles Of Government

While the first DDRI proposal-submission deadline during a calendar year will and, implements the new Uniform Administrative Requirements, Cost Principles, and Program Director, telephone: (703) 292-7301, email: tbaerwal@nsf.gov. so much sugar being used, the government is subsiding the obesity epidemic. Thomas Paine, A Dissertation on the First Principles of Government, 1795. Using first-principles calculations based on hybrid density functional theory, I have investigated Dissertation Title: First-principles calculations of conductivity control in facilities available to university, industry and government researchers.
Fermion Bag Approach to Fermion Sign Problems

The fermion bag approach is a new method to tackle fermion sign problems in lattice field theories. Using this approach it is possible to solve a class of sign problems that seem unsolvable by traditional methods. The new solutions emerge when partition functions are written in terms of fermion bags and bosonic worldlines. In these new variables it is possible to identify hidden pairing mechanisms which lead to the solutions. The new solutions allow us for the first time to use Monte Carlo methods to solve a variety of interesting lattice field theories, thus creating new opportunities for understanding strongly correlated fermion systems.
Statistical Physics of Rupture in Heterogeneous Media

The damage and fracture of materials are technologically of enormous interest due to their economic and human cost. They cover a wide range of phenomena like cracking of glass, aging of concrete, the failure of fiber networks in the formation of paper and the breaking of a metal bar subject to an external load. Failure of composite systems is of utmost importance in naval, aeronautics and space industry [1]. By the term composite, we refer to materials with heterogeneous microscopic structures and also to assemblages of macroscopic elements forming a super-structure. Chemical and nuclear plants suffer from cracking due to corrosion either of chemical or radioactive origin, aided by thermal and/or mechanical stress.
Call Admission Control and Scheduling Policies for UMTS Traffic for QoS Provisioning

The future of wireless data services seems very promising with the advent of third generation (3G) wireless carriers providing a wide variety of data services in conjunction with the existing voice services. To deal with the varied nature of these services, the Universal Mobile Telecommunication System (UMTS)has defined four QoS classes of traffic. However, there exists no service level agreement between the users and the providers on the quality of data services because of the subjectiveness associated with user satisfaction. In this paper, we model user irritation factors using Sigmoid functions which reflect users’ sensitivity and tolerance to QoS provided. We propose call admission control (CAC) algorithms for the four QoS classes and a scheduling mechanism that are specifically designed for the UMTS traffic classes. The CAC and scheduling algorithms jointly attempt to provide a bounded delay for non-real time content. The proposed mechanism takes into consideration the UMTS classes, instantaneous channel conditions, short-term and long-term irritation factors of individual users, fairness within every class and throughput maximization. Simulation experiments conducted with synthetically generated traffic for all four classes demonstrate that the proposed schemes are able to maintain the QoS requirements while maximizing throughput and keeping the churn rate under control.
On search theory and customers

Este articulo estudia un modelo simple de intercambio descentralizado donde los consumidores deben buscar por un vendedor que ofrezca ciertos servicios que se desea adquirir. Una vez que los compradores encuentran uno de estos "buenos" negocios, se desarrolla una relacion de clientela entre ambos. Estudiamos los factores que determinan la formacion de estos vinculos y sus propiedades y caracteristicas. Se define un Equilibrio de Estado Estacionario con Clientes y se establecen condiciones bajo las cuales tal equilibrio existe. Finalmente, se muestra como estas relaciones de clientela imponen cierto rezago en la respuesta de la estructura existente a cambios en los costos de produccion (u otros parametros de la economia).
A Structural Model of Establishment and Industry Evolution : Evidence from Chile

Many recent models have been developed to fit the basic facts on establishment and industry evolution. While these models yield a simple interpretation of the basic features of the data, they are too stylized to confront the micro-level data in a more formal quantitative analysis. In this paper, the author develops a model in which establishments grow by innovating new products. By introducing heterogeneity to a stylized industry evolution model, the analysis succeeds in explaining several features of the data, such as the thick right tail of the size distribution and the relations between age, size, and the hazard rate of exit, which had eluded existing models. In the model, heterogeneity in producer behavior arises through a combination of exogenous efficiency differences and accumulated innovations resulting from past endogenous research and development investments. Integrating these forces allows the model to perform well quantitatively in fitting data on Chilean manufacturers. The counterfactual experiments show how producers respond to research and development subsidies and more competitive market environments.
Self-focusing of optical beams

The nonlinear index of refraction is responsible for self-action effects in optical beam propagation, including self-focusing. We review self-focusing and related phenomena and discuss physical mechanisms that give rise to the refractive index nonlinearity.
Gamma-rays from active galactic nuclei.

Gamma-ray observations from active galactic nuclei (AGN) are important in trying to understand the nature of their central sources. A handful of mechanisms can give rise to γ-rays either from nonthermal or from thermal processes. Hot accretion disks around massive black holes in the centers of AGN could provide the required thermal electrons, pions and relativistic electrons and positrons to explain both the X-ray and γ-ray emission.
The Rational Approximation of Real Functions

Publisher Summary This chapter discusses the rational approximation of real functions. The chapter is closely related to the classical theory of best uniform approximation of continuous functions by quotients of polynomials. The chapter illustrates that if the function being approximated is the real function f, then its best approximation in P n ( ℭ ) is also real, and the problem is reduced to the theory of approximation from P n .
Cohomology and projectivity of modules for finite group schemes

Let G be a finite group scheme over a field k , that is, an affine group scheme whose coordinate ring k [ G ] is finite dimensional. The dual algebra k [ G ]* ≡ Hom k ( k [ G ], k ) is then a finite dimensional cocommutative Hopf algebra. Indeed, there is an equivalence of categories between finite group schemes and finite dimensional cocommutative Hopf algebras (cf. [ 19 ]). Further the representation theory of G is equivalent to that of k [ G ]*. Many familiar objects can be considered in this context. For example, any finite group G can be considered as a finite group scheme. In this case, the algebra k [ G ]* is simply the group algebra kG . Over a field of characteristic p > 0, the restricted enveloping algebra u ([gfr ]) of a p -restricted Lie algebra [gfr ] is a finite dimensional cocommutative Hopf algebra. Also, the mod- p Steenrod algebra is graded cocommutative so that some finite dimensional Hopf subalgebras are such algebras. Over the past thirty years, there has been extensive study of the modular representation theory (i.e. over a field of positive characteristic p > 0) of such algebras, particularly in regards to understanding cohomology and determining projectivity of modules. This paper is primarily interested in the following two questions: Questions 1·1 . Let G be a finite group scheme G over a field k of characteristic p > 0, and let M be a rational G -module. ( a ) Does there exist a family of subgroup schemes of G which detects whether M is projective? ( b ) Does there exist a family of subgroup schemes of G which detects whether a cohomology class z ∈ Ext n G ( M , M ) (for M finite dimensional) is nilpotent?
CROWDING OUT IN RICARDIAN ECONOMIES

Abstract The crowding-out coefficient is the ratio of the reduction in privately-issued bonds to the increase in government bonds that are issued to finance a tax cut. If (1) Ricardian Equivalence holds, and (2) households do not borrow risklessly while holding positive gross positions in other riskless assets, the crowding-out coefficient equals the fraction of the aggregate tax cut that accrues to households that borrow. In the conventional case in which all households receive equal tax cuts, the crowding-out coefficient equals the fraction of households that borrow; in the United States, about 75% of households borrow, so the crowding-out coefficient is predicted to be 0.75. Allowing for cross-sectional variation in tax changes increases the crowding-out coefficient to about 0.85.
The early evolution of stars

This review outlines the observational properties of young stellar objects as they evolve from their birth within dense rotating molecular cores to fully-formed pre-main sequence stars. Current work suggests that most of the mass which ultimately comprises a fully-formed star is transferred from a flattened infalling envelope (of size approximately several thousand AU) through a circumstellar accretion disk to the stellar surface. We summarize current estimates for the duration of the envelope infall and disk accretion phases and discuss the implication of these timescales for the formation of stars of different mass and of planetary systems.
Quantitative patterns in drone wars

Abstract Attacks by drones (i.e., unmanned combat air vehicles) continue to generate heated political and ethical debates. Here we examine the quantitative nature of drone attacks, focusing on how their intensity and frequency compare with that of other forms of human conflict. Instead of the power-law distribution found recently for insurgent and terrorist attacks, the severity of attacks is more akin to lognormal and exponential distributions, suggesting that the dynamics underlying drone attacks lie beyond these other forms of human conflict. We find that the pattern in the timing of attacks is consistent with one side having almost complete control, an important if expected result. We show that these novel features can be reproduced and understood using a generative mathematical model in which resource allocation to the dominant side is regulated through a feedback loop.
Learning from the experiments that never happened : lessons from trying to conduct randomized evaluations of matching grant programs in Africa

Abstract Matching grants are one of the most common policy instruments used by developing country governments to try to foster technological upgrading, innovation, exports, use of business development services and other activities leading to firm growth. However, since they involve subsidizing firms, the risk is that they could crowd out private investment, subsidizing activities that firms were planning to undertake anyway, or lead to pure private gains, rather than generating the public gains that justify government intervention. As a result, rigorous evaluation of the effects of such programs is important. We attempted to implement randomized experiments to evaluate the impact of seven matching grant programs offered in six African countries, but in each case we were unable to complete an experimental evaluation. One critique of development research is publication bias, whereby only “interesting” results get published. Our hope is to mitigate this bias by learning from the experiments that never happened. We describe the three main proximate reasons for lack of implementation: continued project delays, politicians not willing to allow random assignment, and low program take-up; and then delve into the underlying causes of these occurring. Political economy, overly stringent eligibility criteria that do not take account of where value-added may be highest, a lack of attention to detail in “last mile” issues, incentives facing project implementation staff, and the way impact evaluations are funded, and all help explain the failure of randomization. We draw lessons from these experiences for both the implementation and the possible evaluation of future projects.
The inverse problem for the local geodesic ray transform

Under a convexity assumption on the boundary we solve a local inverse problem, namely we show that the geodesic X-ray transform can be inverted locally in a stable manner; one even has a reconstruction formula. We also show that under an assumption on the existence of a global foliation by strictly convex hypersurfaces the geodesic X-ray transform is globally injective. In addition we prove stability estimates and propose a layer stripping type algorithm for reconstruction.
A Bayesian variant of Shafer's commonalities for modelling unforeseen events

Shafer's theory of belief and the Bayesian theory of probability are two alternative and mutually inconsistent approaches toward modelling uncertainty in artificial intelligence. To help reduce the conflict between these two approaches, this paper reexamines expected utility theory -- from which Bayesian probability theory is derived. Expected utility theory requires the decision maker to assign a utility to each decision conditioned on every possible event that might occur. But frequently the decision maker cannot foresee all the events that might occur, i.e., one of the possible events is the occurrence of an unforeseen event. So once we acknowledge the existence of unforeseen events, we need to develop some way of assigning utilities to decisions conditioned on unforeseen events. The commonsensical solution to this problem is to assign similar utilities to events which are similar. Implementing this commonsensical solution is equivalent to replacing Bayesian subjective probabilities over the space of foreseen and unforeseen events by random set theory probabilities over the space of foreseen events. This leads to an expected utility principle in which normalized variants of Shafer's commonalities play the role of subjective probabilities. Hence allowing for unforeseen events in decision analysis causes Bayesian probability theory to become much more similar to Shaferian theory.
New estimates of U.S. currency abroad, the domestic money supply and the unreported Economy

Despite financial innovations that have created important new substitutes for cash usage, per capita holdings of U.S. currency amount to $2950. Yet American households and businesses admit to holding only 15% of the currency stock, leaving the whereabouts of 85% unknown. Some fraction of this unaccounted for currency is held abroad (the dollarization hypothesis) and some is held domestically undeclared, as a store of value and a medium of exchange for transactions involving the production and distribution of illegal goods and services, and for transactions earning income that is not reported to the IRS (the unreported economy hypothesis). We find that the percentage of U.S. currency currently held overseas is between 30 and 37% rather than the widely cited figure of 65%. This finding is based on the official Federal Reserve/Bureau of Economic Analysis data which is a proxy measure of the New York Federal Reserve’s (NYB) “confidential” data on wholesale currency shipments abroad. We recommend that the NYB data be aggregated so as to circumvent confidentiality concerns, and be made readily available to all researchers in order to shed greater light on the questions of how much U.S. currency is abroad and on the particular location of overseas U.S. dollars. The newly revised official estimates of overseas currency holdings are employed to determine the Federal Reserve’s seigniorage earnings from 1964–2010, which have provided a $287 billion windfall for U.S. taxpayers. Overseas currency stock data are also used to derive estimates of the domestically held stock of currency as well as narrow and broad measures of domestic monetary aggregates. These domestic monetary aggregates are believed to be better predictors of future economic activity than traditional monetary aggregates and are tested to determine their ability to predict fluctuations in real output and prices. Domestic cash holdings are finally used to estimate the size of the U.S. unreported economy as measured by the amount of income that is not properly reported to the IRS. By 2010, we estimate that legal and illegal source unreported income” is $1.9–$2.4 trillion, implying a “tax gap” in the range of $400–$540 billion. Currently, we estimate that 18–23% of total reportable income is not properly reported to the IRS.
Financial constraints, working capital and the dynamic behavior of the firm

Financial constraints are widespread in developing countries, where even short-term credit is limited. Finance held by firms as working capital is a substantial proportion of sales revenue, yet the role of working capital is largely neglected by existing models of financial constraints. This paper presents a dynamic model of the firm that incorporates working capital by introducing a delay between factor payments and the receipt of revenue. In contrast with previous models, the working capital model predicts that firms under binding constraints will substitute between labor and capital in response to demand shocks, causing investment to be countercyclical. For firms near the margin of being constrained, constraints bind when positive production opportunities arise. Output growth is therefore constrained in response to positive shocks but not to negative shocks. Simulations suggest that models without working capital may understate the predicted effects of financial constraints on production efficiency, firm profit and growth over time. The predictions are tested with the Bangladesh Panel Survey data for manufacturing firms. Consistent with the theory, there is evidence that constraints bind when output price increases, that investment by constrained firms is countercyclical, and that output response to positive shocks is dampened for firms that are sometimes constrained. The results also are important for policy. In order to maximize growth, efforts to relieve credit constraints should be focused on periods when demand shocks are high.
Interdiction problems on planar graphs

Interdiction problems are leader-follower games in which the leader is allowed to delete a certain number of edges from the graph in order to maximally impede the follower, who is trying to solve an optimization problem on the impeded graph. We introduce approximation algorithms and strong NP-completeness results for interdiction problems on planar graphs. We give a multiplicative ( 1 + ? ) -approximation for the maximum matching interdiction problem on weighted planar graphs. The algorithm runs in pseudo-polynomial time for each fixed ? 0 . We also show that weighted maximum matching interdiction, budget-constrained flow improvement, directed shortest path interdiction, and minimum perfect matching interdiction are strongly NP-complete on planar graphs. To our knowledge, our budget-constrained flow improvement result is the first planar NP-completeness proof that uses a one-vertex crossing gadget.
Towards a separation of semantic and CCA security for public key encryption

We address the question of whether or not semantically secure public-key encryption primitives imply the existence of chosen ciphertext attack (CCA) secure primitives. We show a black-box separation, following the methodology introduced by Impagliazzo and Rudich [23], for a large non-trivial class of constructions. In particular, we show that if the proposed CCA construction's decryption algorithm does not query the semantically secure primitive's encryption algorithm, then the proposed construction cannot be CCA secure.
An efficient method to estimate processing rates in streams

[1] We provide an efficient method to estimate processing rates through simple algebraic relationships derived from the transient storage model equations. The method is based on the transport equations, but eliminates the need to calibrate highly uncertain (and intermediate) parameters. We demonstrate that under some common stream transport conditions dispersion does not play an important role in the estimation of processing rates and, therefore, can be neglected. Under such conditions, no computer modeling is needed to estimate processing rates. We also derive algebraic equations to estimate processing rates of target solutes (such as dissolved oxygen) with proxy-tracers (such as resazurin), and show that even if both the target and proxy reactions happen in exactly the same locations at rates that are linearly proportional, the exact relationship between the two volume-averaged rates can be nonlinear and a function of transport. However, the uncertainty in the estimation of the target processing rate is linearly proportional to the proxy-tracer processing rate.
Privatization in competitive sectors : the record to date

The paper reviews recent evidence on the impact of privatization. It focuses on traditional privatization efforts involving firms in competitive markets. It shows that privatization improves firms' financial and operating performance, yields positive fiscal and macroeconomic benefits (proceeds are saved rather than spent, transfers decline, and governments start collecting taxes from privatized firms), and improves overall welfare. The popular view that privatization always leads to layoffs is unfounded. While highly protected firms have seen significant declines in net employment, competitive firms generally experienced slight declines if any. Privatization's effects on wealth and income distribution have only recently been receiving the attention of analysts, and research is just getting underway. The paper highlights the conditions for successful privatization: strong political commitment combined with wider public understanding of and support for the process; creation of competitive markets through removal of entry and exit barriers, financial sector reforms that create commercially oriented banking systems, effective regulatory frameworks that reinforce the benefits of private ownership; transparency in the privatization process; and measures to mitigate adverse social and environmental effects.
CHAPTER 11 - Nervous Systems

Insects use both the endocrine and the nervous systems for information transfer between their cells, with each system having its own advantages and constraints. Biological information transmitted by the electrical signals of the nervous system provides a much more rapid means for coordinating cellular events than that transmitted by hormones or chemical messengers. This chapter examines aspects of nervous transmission in insects. Nerve cells, or neurons, are the cellular building blocks that make up the nervous system. They are capable of integrating information, undergoing excitation, and transmitting the information by electrical and short-range chemical signaling. Maintenance of electrical potential in dendrites of neurons help in neural transmission. A number of different neurotransmitters and neuromodulators are involved in nervous transmission at both invertebrate and vertebrate synapses. The synaptic connection of a single neuron with two or more neurons, or with a muscle cell innervated by multiple motor neurons that includes neurotransmitters capable of exciting or inhibiting at the synapse, allows the nervous system to integrate nervous transmission in a much more complex fashion. The insect central nervous system consists of the brain and ventral nerve cord. The system comprises the individual neurons that are associated in functional groupings that evolved together with a reorganization of the insect body from its primitive annelid-like ancestor. The peripheral nervous systeminvolves all the nerves that radiate from the central nervous system. These include the nerves that innervate muscles, stretch receptors that may serve as proprioreceptors, innervations of the reproductive system and spiracles, and the various sensory receptors. Another part of the insect nervous system, termed visceral nervous system, innervates the gut, heart, and endocrine glands and forms a network of peripheral ganglia that is associated with digestive processes.
Disease-free survival following high dose or standard dose therapy in patients with amyloidosis.

Keywords: bortezomib; melphalan; autologous haematopoietic cell rescue; treatment related mortality
An Assessment of the Investment Climate in Kenya

Nigeria's vision of 2020 is a bold desire to be among the top twenty economies by the year 2020. The economy has posted impressive growth figures since 2003 driven by higher oil prices and a series of home-grown, economic reforms. The country is now firmly on the road to middle-income status. This Investment Climate Analysis is built on a 2,300 firm survey and provides evidence-based recommendations designed to support the vision 2020. Survey results represent investment climate status in Nigeria and are grouped by the following topics: firm productivity and business environment, comparison of state level investment climates, access to finance, entrepreneurship and managerial capacity in firms, and investment climate aspects. The authors conclude that stakeholder consultations on the diagnostic work, policy assessment, and design would improve Nigeria's investment climate.
User requirements of mobile technology: A summary of research results

As advanced mobile technology becomes more widespread, the impacts on professional environments and on the personal lives of individual users continue to increase. Devices, such as smart cell phones, personal digital assistants (PDAs), and laptop computers can free their owners of the need to remain close to a wired information system infrastructure that is provided in a stationary office environment, and provide the opportunity to perform tasks in a wide variety of use contexts. With changes in use context, however, come changes in requirements, such as the need to limit weight and size of a device. In order to achieve success in the form of adoption, use, and positive impacts on user performance, a thorough understanding is needed about the functional and non-functional technology requirements of mobile professionals. In this paper, we summarize the results of a series of research studies that we conducted to explore the technology requirements of mobile professionals. The research studies included a content analysis of online user reviews, two empirical surveys, and a series of user interviews. Our research findings indicate that (1) user-perceived technology maturity is a critical factor to explain and predict the use of mobile technology by mobile professionals; (2) mobile technology needs to be available in a broad variety of use-situations; (3) users require basic communication and productivity-related functionality, in particular to support non-routine and supervisory task profiles; and (4) mobile technology can have considerable impacts on the job performance and on the personal lives of its users. Our findings have implications for the design, management, and research of mobile information systems.
On Standard Finite Difference Discretizations of the Elliptic Monge---Ampère Equation

Given an orthogonal lattice with mesh length h on a bounded two-dimensional convex domain $${\varOmega }$$Ω, we propose to approximate the Aleksandrov solution of the Monge---Ampere equation by regularizing the data and discretizing the equation in a subdomain using the standard finite difference method. The Dirichlet data is used to approximate the solution in the remaining part of the domain. We prove the uniform convergence on compact subsets of the solution of the discrete problems to an approximate problem on the subdomain. The result explains the behavior of methods based on the standard finite difference method and designed to numerically converge to non-smooth solutions.
Remote Oxidation of Aliphatic C–H Bonds in Nitrogen-Containing Molecules

Nitrogen heterocycles are ubiquitous in natural products and pharmaceuticals. Herein, we disclose a nitrogen complexation strategy that employs a strong Bronsted acid (HBF4) or an azaphilic Lewis acid (BF3) to enable remote, non-directed C(sp3)–H oxidations of tertiary, secondary, and primary amine- and pyridine-containing molecules with tunable iron catalysts. Imides resist oxidation and promote remote functionalization.
Status report on next-generation LADAR for driving unmanned ground vehicles

The U.S. Department of Defense has initiated plans for the deployment of autonomous robotic vehicles in various tactical military operations starting in about seven years. Most of these missions will require the vehicles to drive autonomously over open terrain and on roads which may contain traffic, obstacles, military personnel as well as pedestrians. Unmanned Ground Vehicles (UGVs) must therefore be able to detect, recognize and track objects and terrain features in very cluttered environments. Although several LADAR sensors exist today which have successfully been implemented and demonstrated to provide somewhat reliable obstacle detection and can be used for path planning and selection, they tend to be limited in performance, are effected by obscurants, and are quite large and expensive. In addition, even though considerable effort and funding has been provided by the DOD R&D community, nearly all of the development has been for target detection (ATR) and tracking from various flying platforms. Participation in the Army and DARPA sponsored UGV programs has helped NIST to identify requirement specifications for LADAR to be used for on and off-road autonomous driving. This paper describes the expected requirements for a next generation LADAR for driving UGVs and presents an overview of proposed LADAR design concepts and a status report on current developments in scannerless Focal Plane Array (FPA) LADAR and advanced scanning LADAR which may be able to achieve the stated requirements. Examples of real-time range images taken with existing LADAR prototypes will be presented.
TakeoverTV: Facilitating the social negotiation of television content in public spaces

Social television, in essence, is a way to share and experience media with others. Rather than attempt to bridge physical distance by creating new social experiences, we have built a system called TakeoverTV that augments canonical social interactions by addressing three key questions: 1. How can we better support social gatherings around media in public and private places? 2. How can we enable conversation across our devices rather than forcing us to communicate through them? 3. How can we help people come to agreements about what media they want to watch together? Primarily aimed at public spaces like bars, TakeoverTV is a system that lets local users influence and interact with the movies and television programs shown on public displays. Our system collects the media preferences of all people physically present at a given location, lets users start a vote among all members of the space, and allows everyone to participate using tangible physical objects like tables in addition to smart devices. Over time, public establishments can evolve complex identities based on the preferences and votes of their patrons while generating valuable analytic data for patrons, establishment owners, content-providers, and advertisers alike.
Sequential diastereoselective free radical reactions: Synthesis of an advanced olivomycin A C–D disaccharide

Abstract The synthesis of an advanced olivomycin A C–D disaccharide is described in which the anomeric configuration of both 2-deoxy-β-glycosidic linkages is determined by a sequential diastereoselective radical reaction at the end of the synthesis.
An introduction to biomolecular simulations and docking

The biomolecules in and around a living cell – proteins, nucleic acids, lipids and carbohydrates – continuously sample myriad conformational states that are thermally accessible at physiological te...
Selecting random number seeds in practice

A pseudorandom number generator, such as a multiplicative con gruential generator, depends on its initial value or seed. The com puter may select a seed using its internal clock. Alternatively the simulation analyst may use Fishman's tables with seeds spaced 100 000 apart. Theoretically, the concepts of sampling with and without replacement are involved. Practical problems arise if con secutive simulation runs cannot be made in a single terminal session. The user may select the simplest option. Runs for dif ferent systems may use common seeds to decrease the variability; then the internal clock is an impractical source since its inter nal (binary) representation must be saved.
The synthesis of several imidazo[4,5‐d]isothiazoles. Derivatives of a new ring system

Several derivatives of the new imidazo[4,5-d]isothiazole ring system have been synthesized from the appropriately substituted isothiazolediamines. The reaction of 3-methyl-4,5-diaminoisothiazole (4a) with diethoxy-methyl acetate gave a low yield of 3-methylimidazo[4,5-d]isothiazole (5a). However, the analogous reaction of 4,5-diaminoisothiazole (4b) with diethoxymethyl acetate failed to yield the parent imidazo[4,5-d]isothiazole ring system. The diamines 4a and 4b were readily cyclized with thiocarbonyldiimidazole to give the unstable thiones 6a and 6b, which were alkylated in situ to afford good yields of the corresponding 5-methylthioimidazo[4,5-d]isothiazoles 7a and 7b, respectively. Neither of these compounds could be reduced to the corresponding 5-unsubstituted derivatives via treatment with Raney nickel. To the best of our knowledge, this is the first report of the imidazo[4,5-d]isothiazole ring system.