cssi/SciSciGPT-SciSciNet huggingface dataset:
Correspondence between lifetime minimum wealth and utility of consumption

We establish when the two problems of minimizing a function of lifetime minimum wealth and of maximizing utility of lifetime consumption result in the same optimal investment strategy on a given open interval O in wealth space. To answer this question, we equate the two investment strategies and show that if the individual consumes at the same rate in both problems—the consumption rate is a control in the problem of maximizing utility—then the investment strategies are equal only when the consumption function is linear in wealth on O, a rather surprising result. It then follows that the corresponding investment strategy is also linear in wealth and the implied utility function exhibits hyperbolic absolute risk aversion.
A direct preparation of 1,2-diacetates from aldehydes and ketones promoted by samarium diiodide

Abstract In a mild reaction mediated by samarium diiodide, ketones and aldehydes have been converted into 1,2-diacetates from commercially available bromomethyl acetate in a single synthetic transformation.
The characteristics of mathematical creativity

Mathematical creativity ensures the growth of mathematics as a whole. However the source of this growth, the creativity of the mathematician is a relatively unexplored area in mathematics and mathematics educa- tion. In order to investigate how mathematicians create mathematics; a qualitative study involving five creative mathematicians was conducted. The mathematicians in this study verbally reflected on the thought processes involved in creating mathematics. Analytic induction was used to analyze the qualitative data in the interview transcripts and to verify the theory driven hypotheses. The results indicate that in general, the mathematicians' creative process fol- lowed the four-stage Gestalt model of preparation- incubation-illumination-verification. It was found that social interaction, imagery, heuristics, intuition, and proof were the common characteristics of mathematical creativ- ity. In addition contemporary models of creativity from psychology were reviewed and used to interpret the char- acteristics of mathematical creativity.
Calculus with a quaternionic variable

Most of theoretical physics is based on the mathematics of functions of a real or a complex variable; yet we frequently are drawn in trying to extend our reach to include quaternions. The noncommutativity of the quaternion algebra poses obstacles for the usual manipulations of calculus, but we show in this paper how many of those obstacles can be overcome. The surprising result is that the first order term in the expansion of F(x+δ) is a compact formula involving both F′(x) and [F(x)−F(x∗)]/(x−x∗). This advance in the differential calculus for quaternionic variables also leads us to some progress in studying integration.
Investigation of regularized neural networks for the computerized detection of mass lesions in digital mammograms

Computerized schemes are currently being developed at the University of Chicago to detect mass lesions in digital mammograms. Artificial neural networks play an important role in the detection of masses. Currently, features are extracted from potential lesion areas and sent through a neural network to decide whether the area is to be called a true lesion or a false detection. One of the most difficult aspects of dealing with artificial neural networks is to train them without over-training; in other words, to take both the bias and variance into account when training. Typically, an early stopping technique is employed; that is, the neural network is tested on an independent data set and training is stopped when the the performance on this independent data set is maximized. In this paper the effectiveness of regularization is evaluated as a technique to minimize over-training. Regularization adds an extra term to the cost-function used in neural network training that penalizes over-complex results. The results of simulation studies will be presented along with results obtained using data of actual lesions and false positives from the authors' computerized mass detection scheme.
Observational Constraints on the Self-interacting Dark Matter Scenario and the Growth of Supermassive Black Holes

We consider the astrophysical consequences of the self-interacting dark matter (SIDM) scenario for a general velocity-dependent cross section per unit mass that varies as some power of velocity: σDM = σ0 -a. Accretion of SIDM onto seed black holes can produce supermassive black holes that are too large for certain combinations of σ0v and a, a fact that is used to obtain a new constraint on the dark matter interaction. Constraints due to other astrophysical considerations are presented and previous constraints for a constant cross section are generalized. The black hole constraint is extremely sensitive to the cusp slope, α, of the inner density profile ρ ~ r-α of dark halos. For the most probable value of α = 1.3, we find that there exists a tiny region in the parameter space for SIDM properties, with a ≈ 0.5 and a ≈ 0.5, such that all constraints are satisfied. However, the adiabatic compression of the dark halo by baryons as they cool and contract in normal galaxies yields a steeper cusp, ρ ~ r. We find that in both the highly collisional and collisionless limits invariance arguments require α' = (6 - α) (4 - α), where α and α' are the (4α) inner profile slope of the dark halo before and after compression, respectively. This gives the tighter constraint a 0.02, which would exclude SIDM as a possible solution to the purported problems with cold dark matter (CDM) on subgalactic scales in the absence of other dynamical processes. Nevertheless, SIDM with parameters consistent with this stronger constraint, can explain the ubiquity of supermassive black holes in the centers of galaxies. A "best-fit" model is presented with a = 0 and = 0.02, which reproduces the supermassive black hole masses and their observed correlations with the velocity dispersion of the host bulges. Specifically, the approximately fourth-power dependence of black hole mass on galactic velocity dispersion is a direct consequence of the power spectrum of primeval perturbations having an index of n ≈ -2 and the value of a. Although the dark matter collision rates for this model are too small to directly remedy problems with CDM, mergers between dark halos harboring supermassive black holes at high redshift could ameliorate the cuspy halo problem. This scenario also explains the lack of comparable supermassive black holes in bulgeless galaxies like M33.
Routh-Hurwitz criterion in the examination of eigenvalues of a system of nonlinear ordinary differential equations.

In stability analysis of nonlinear systems, the character of the eigenvalues of the Jacobian matrix (i.e., whether the real part is positive, negative, or zero) is needed, while the actual value of the eigenvalue is not required. We present a simple algebraic procedure, based on the Routh-Hurwitz criterion, for determining the character of the eigenvalues without the need for evaluating the eigenvalues explicitly. This procedure is illustrated for a system of nonlinear ordinary differential equations we have studied previously. This procedure is simple enough to be used in computer code, and, more importantly, makes the analysis possible even for those cases where the secular equation cannot be solved.
Developing A Culturally Responsive Classroom Collaborative Of Faculty, Students, And Institution

Culture is integral to the learning process. It is the organization and way of life within the community of students and teachers and directs the way they communicate, interact, and approach teaching and learning. Although founded in particular values and principles, the academy, like most organizations, is impacted day-to-day by its culture. Yet, the traditional higher education institution has not been designed to operate within a racially or ethnically diverse student population. The social, political, economic, and cultural forces that support the institution influence the teaching and learning environments. To better address cultural diversity in the classroom, faculty must first examine their own cultural background and understand how biases may affect their interactions with students. To advance teaching and learning in the college classroom requires an understanding of the underlying values, beliefs, perceptions and assumptions of students, which affect their understanding of what they hear and read as well as how they express themselves in the classroom. When teachers recognize these different qualities, classroom instruction can be designed to connect content to students’ backgrounds. This paper examines one approach to building a teaching and learning community through faculty professional development and collaboration. It provides an overview of a 5-part workshop series conducted for faculty at the Johnson & Wales University Providence campus on intercultural learning and culturally responsive teaching. Focusing on the essential components of personalizing culture through the five institutions of family, school, religion, politics, and economics through workshop activities, it is an investigation of individual and institutional backgrounds to determine how faculty may recognize the forces that influence student behavior, and how to engage them in a more active learning process.
Performance prediction for handwritten word recognizers and its application to classifier combination

This paper introduces a performance prediction model for handwritten word recognizers. This model considers the factors involved in word recognition, i.e., the recognizer, input images and lexicons, and presents a quantitative formula to associate performance with these factors. It produces a direct measure of recognition difficulty by the predicted performance which can be utilized to improve the combination of multiple recognizers. We support the accuracy of our model by extensive experiments conducted on five word recognizers and its applications to multiple classifier systems.
The dynamics of city formation

This paper examines city formation in a country whose urban population is growing steadily over time, with new cities required to accommodate this growth. In contrast to most of the literature there is immobility of housing and urban infrastructure, and investment in these assets is taken on the basis of forward-looking behavior. In the presence of these fixed assets cities form sequentially, without the population swings in existing cities that arise in current models, but with swings in house rents. Equilibrium city size, absent government, may be larger or smaller than is efficient, depending on how urban externalities vary with population. Efficient formation of cities with internalization of externalities involves local government intervention and borrowing to finance development. The paper explores the institutions required for successful local government intervention.
Symposium on Social Capital: Introduction

This symposium contains three papers that discuss aspects of social capital. Social capital has become a major focus of research in many social sciences. Its increased prominence in economics reflects a general increase in interest in questions that have traditionally been deemed sociological. Regardless of one's opinion of social capital per se, this broadening of questions addressed within economics has been very salutary.
T Cell-Dependent B Cell Activation

B cells obtain help from T cells in the antibody response by acting as antigen-specific antigen presenting cells. A direct signal through binding of antigen to membrane Ig can enhance B cell antigen presentation and T-dependent B cell activation, but is not required for a productive interaction between a small resting B cell and a differentiated helper T cell. As a result of helper T cell recognition of antigen on the B cell surface, the T cell becomes activated and in turn activates the B cell. T cell help has two components: lymphokines which act as growth and differentiation factors for B cells, and additional signals which require cell contact and enable B cells to respond to lymphokines. Contact help activity is regulated like lymphokine synthesis and secretion. Because contact help activity is retained by fixed, activated helper T cells and plasma membranes prepared from activated T cells, contact help is likely to be owing to new proteins expressed as membrane-bound lymphokines or activation antigens on helper T cells. Once induced, contact help can be delivered to B cells independently of recognition of antigen/class II MHC. A newly identified activation antigen of helper T cells, a ligand for the B cell differentiation antigen, CD40, is a key component of contact help. The roles of other T and B cell membrane molecules in contact help are reviewed.
Supersymmetry in quantum mechanics: an extended view

The concept of supersymmetry in a quantum-mechanical system is extended, permitting the recognition of more supersymmetric systems, including very familiar ones such as the free particle. Its spectrum is shown to be supersymmetric upon taking into account physical reasonableness of the wavefunctions involved. Spacetime symmetries are used for the construction of the supercharges without explicit invocation of fermionic or Grassmann variables. Most notably, while the free particle in one dimension has generally been regarded as having a doubly degenerate continuum throughout, the construction clarifies that there is a single zero-energy state at the base of the spectrum.
Comparison of cobordism theories

Abstract Relying on results of Hopkins–Morel, we show that, for X a quasi-projective variety over a field of characteristic zero, the canonical map Ω n ( X ) → MGL 2 n , n ′ ( X ) is an isomorphism.
An Attractive Method for Displaying Material Damping Data

This paper describes the development of a new reduced-temperature nomogram which greatly facilitates the display and correlation of complex modulus data for a linear thermorheologically simple viscoelastic damping material in such a way that the effects of frequency and temperature can be simultaneously taken into account. The method is based on the well-known temperature-frequency equivalence principle, which allows one to modify the frequency by a factor depending on temperature alone in such a way that complex modulus data points at a given frequency and temperature can be combined into a single set of curves, representing the loss factor and modulus as a function of a single variable, known as the reduced frequency. The superimposition of temperature isotherms completes the nomogram and thereby greatly expands the usefulness of the reducedfrequency graphs by allowing display on a single graph of complex modulus data at any frequency and temperature. This allows the possibility of generating and transmitting engineering data on viscoelastic material behavior to be used in many areas where such materials are being considered for vibration control. The nomogram is currently being used by industry and is being considered for national and international standards relating to display of engineering data for damping materials.
New, optically active phosphine oxazoline (JM-Phos) ligands: syntheses and applications in allylation reactions.

Three different syntheses of the phosphine oxazoline systems 1 are presented. Two of these approaches are divergent routes designed to involve an advanced intermediate that can be transformed into several different end-products. The third is a shorter route specifically designed to facilitate preparations of these systems on a larger scale using minimal functional group protection. Overall, eight different phosphine oxazolines were prepared. These were screened in several palladium-mediated allylation reactions. They proved to be most useful for asymmetric alkylation of 3-acetoxy-1,3-diphenylpropene and less suitable/effective for the more challenging substrates (a pentenyl derivative and a cyclohexenyl system). X-ray crystallographic analysis of the complex [(η3-PhCHCHCHPh)Pd(1a)][PF6] led to the conclusion that the origins of asymmetric induction in these systems might be indirectly attributed to interaction of the oxazoline-phenyl substituent with the palladium and with an allyl-phenyl substituent. Fin...
Catalytic Alkene Cyclization Reactions for the Stereoselective Synthesis of Complex “Terpenoid-like” Heterocycles

A new catalytic synthesis of densely substituted tetrahydroquinolines is described. This reaction forms up to two rings, three bonds, and three stereogenic centers with excellent stereo- and regiocontrol in a single step. Although control experiments demonstrate that the active catalyst is protic acid, Sc(OTf)3 serves as an effective and practical pre-catalyst. The scope of this reaction is demonstrated with 21 monocyclizations and 14 bicyclization reactions.
Exponential Family Matrix Completion under Structural Constraints

We consider the matrix completion problem of recovering a structured matrix from noisy and partial measurements. Recent works have proposed tractable estimators with strong statistical guarantees for the case where the underlying matrix is low-rank, and the measurements consist of a subset, either of the exact individual entries, or of the entries perturbed by additive Gaussian noise, which is thus implicitly suited for thin-tailed continuous data. Arguably, common applications of matrix completion require estimators for (a) heterogeneous data-types, such as skewed-continuous, count, binary, etc., (b) for heterogeneous noise models (beyond Gaussian), which capture varied uncertainty in the measurements, and (c) heterogeneous structural constraints beyond low-rank, such as block-sparsity, or a superposition structure of low-rank plus elementwise sparseness, among others. In this paper, we provide a vastly unified framework for generalized matrix completion by considering a matrix completion setting wherein the matrix entries are sampled from any member of the rich family of exponential family distributions; and impose general structural constraints on the underlying matrix, as captured by a general regularizer R(.). We propose a simple convex regularized M-estimator for the generalized framework, and provide a unified and novel statistical analysis for this general class of estimators. We finally corroborate our theoretical results on simulated datasets.
Multi-source cooperation with full-diversity spectral-efficiency and controllable-complexity

A general framework is developed for multi-source cooperation (MSC) protocols to improve diversity and spectral efficiency relative to repetition based alternatives that rely on single-source cooperation. The novel protocols are flexible to balance tradeoffs among diversity, spectral efficiency and decoding-complexity. Users are grouped in clusters and follow a two-phase MSC protocol which involves time division multiple access (TDMA) to separate users within a cluster, and code division multiple access (CDMA) used to separate clusters. An attractive protocol under the general MSC framework relies on distributed complex field coding (DCFC) to enable diversity order equal to the number of users per cluster. Cluster separation based on orthonormal spreading sequences leads to spectral efficiency 1/2. When the number of clusters exceeds the amount of spreading, spectral efficiency can be enhanced without sacrificing diversity, at the expense of controllable increase in complexity. Simulations corroborate our analytical claims
Time Variation in the Inflation Passthrough of Energy Prices

From Bayesian estimates of a vector autoregression (VAR) which allows for both coefficient drift and stochastic volatility, we obtain the following three results. First, beginning in approximately 1975, the responsiveness of core inflation to changes in energy prices in the United States fell rapidly and remains muted. Second, this decline in the passthrough of energy inflation to core prices has been sustained through a recent period of markedly higher volatility of shocks to energy inflation. Finally, reduced energy inflation passthrough has persisted in the face of monetary policy which quickly became less responsive to energy inflation starting around 1985.
$(\log t)^{2/3}$ law of the two dimensional asymmetric simple exclusion process

We prove that the diffusion coefficient for the two dimensional asymmetric simple exclusion process with nearest-neighbor-jumps diverges as (log t) 2/3 to the leading order. The method applies to nearest and non-nearest neighbor asymmetric simple exclusion processes.
Titanium-catalyzed iminohydrazination of alkynes

Abstract Titanium pyrrolyl complexes Ti(NMe2)2(dap)2 (1), where dap is 2-(N,N-dimethylaminomethyl)pyrrolyl, and Ti(NMe2)3(bap) (3), where bap is 2,5-bis(N,N-dimethylaminomethyl)pyrrolyl, were found to be effective catalysts for the iminohydrazination of alkynes, a new multicomponent coupling reaction involving an alkyne, hydrazine, and isonitrile. A brief study on the scope of the reaction suggests that it is applicable to internal and terminal alkynes, alkyl and aryl isonitriles, and alkyl- and aryl-containing 1,1-disubstituted hydrazines. The best yields were obtained with terminal alkynes and alkyl isonitriles. The regioselectivity of the reactions is quite sensitive to catalyst structure, and, in all cases, we were able to obtain one regioisomer of the iminohydrazination product with either 1 or 3 as catalyst. The conformation of the products was probed by NMR spectroscopy and DFT calculations, which suggest that the s-cis isomer of the hydrazone–enamine tautomer is the most favorable configuration. However, several configurations are probably accessible in solution at room temperature. Reaction of 1 with 2 equivalents of H2NNMe2 results in the formation of a dinuclear complex Ti2(dap)3(NNMe2)2(NHNMe2) (4), where one dap ligand was removed protolytically. Examination of regioselectivities in iminohydrazination reactions using 4 and mono(dap) complex Ti(dap)(NMe2)3 (5) are consistent with these species using the same catalytic cycle as 1. Consequently, the active species is likely a mono(dap) titanium complex. Current mechanistic information is consistent with a hydrazido(2−) intermediate and a pathway reminiscent of the Bergman hydroamination mechanism. Ti(NMe2)3(bap) (3) and Ti2(dap)3(NNMe2)2(NHNMe2) (4) were characterized by X-ray diffraction.
Institutional Investment and the Turn-of-the-Month Effect: Evidence from REITs

Many studies have hypothesized that the turn-of-the-month effect is caused by institutional investment. However, there is little evidence to support this hypothesis. This study provides an empirical test that measures the impact of the level of institutional investment on the turn-of-the-month effect using a sample of REITs over the period 1980 to 2004. We find that a significant change in the turn-of-the-month effect occurred following the Omnibus Reconciliation Act of 1993 which relaxed the requirements on the level of institutional investment in REITs. The evidence suggests that the dramatic rise in institutional holdings can account for a good part of this change. However, the impact of institutional investment may not be as large as some researchers have suspected. There is no evidence to suggest that institutional investment impacts returns on the day when the turn-of-the-month effect is most pronounced, suggesting that this calendar anomaly is not caused exclusively by institutional investors in the market.
Quantitative Accuracy of Penalized-Likelihood Reconstruction for ROI Activity Estimation

Estimation of the tracer uptake in a region of interest (ROI) is an important task in emission tomography. ROI quantification is essential for measuring clinical factors such as tumor activity, growth rate, and the efficacy of therapeutic interventions. Accuracy of ROI quantification is significantly affected by image reconstruction algorithms. In penalized maximum-likelihood (PML) algorithm, the regularization parameter controls the resolution and noise tradeoff and, hence, affects ROI quantification. To obtain the optimum performance of ROI quantification, it is desirable to use a moderate regularization parameter to effectively suppress noise without introducing excessive bias. However, due to the non-linear and spatial-variant nature of PML reconstruction, choosing a proper regularization parameter is not an easy task. Our previous theoretical study (Qi and Huesman, IEEE Trans. Med. Imag., 2006) has shown that the bias-variance characteristic for ROI quantification task depends on the size and activity distribution of the ROI. In this work, we design physical phantom experiments to validate these predictions in a realistic situation. We found that the phantom data results match well the theoretical predictions. The good agreement between the phantom results and theoretical predictions shows that the theoretical expressions can be used to predict the accuracy of ROI activity quantification.
Sprinklers: A Randomized Variable-Size Striping Approach to Reordering-Free Load-Balanced Switching

Internet traffic continues to grow exponentially, calling for switches that can scale well in both size and speed. While load-balanced switches can achieve such scalability, they suffer from a fundamental packet reordering problem. Existing proposals either suffer from poor worst-case packet delays or require sophisticated matching mechanisms. In this paper, we propose a new family of stable load-balanced switches called "Sprinklers" that has comparable implementation cost and performance as the baseline load-balanced switch, but yet can guarantee packet ordering. The main idea is to force all packets within the same virtual output queue (VOQ) to traverse the same ``fat path'' through the switch, so that packet reordering cannot occur. At the core of Sprinklers are two key innovations: a randomized way to determine the "fat path" for each VOQ, and a way to determine its "fatness" roughly in proportion to the rate of the VOQ. These innovations enable Sprinklers to achieve near-perfect load-balancing under arbitrary admissible traffic. Proving this property rigorously using novel worst-case large deviation techniques is another key contribution of this work.
SCHEDULING SENSORS BY TILING LATTICES

Suppose that wirelessly communicating sensors are placed in a regular fashion on the points of a lattice. Common communication protocols allow the sensors to broadcast messages at arbitrary times, which can lead to problems should two sensors broadcast at the same time. It is shown that one can exploit a tiling of the lattice to derive a deterministic periodic schedule for the broadcast communication of sensors that is guaranteed to be collision-free. The proposed schedule is shown to be optimal in the number of time slots.
The asymptotic behavior of degenerate oscillatory integrals in two dimensions

Abstract A theorem of Varchenko gives the order of decay of the leading term of the asymptotic expansion of a degenerate oscillatory integral with real-analytic phase in two dimensions. His theorem expresses this order of decay in a simple geometric way in terms of its Newton polygon once one is in certain coordinate systems called adapted coordinate systems. In this paper, we give explicit formulas that not only provide the order of decay of the leading term, but also the coefficient of this term. There are three rather different formulas corresponding to three different types of Newton polygon. Analogous results for sublevel integrals are proven, as are some analogues for the more general case of smooth phase. The formulas require one to be in certain “superadapted” coordinates. These are a type of adapted coordinate system which we show exists for any smooth phase.
A Small PRG for Polynomial Threshold Functions of Gaussians

We discuss a psuedorandom generator to $\epsilon$-fool degree-d polynomial threshold functions with respect to the Gaussian distribution with seed length $2^O_c(d)\log(n) \epsilon^{-4-c}$. Our analysis involves several new ideas including what we term the "noisy derivative" of a function and a stronger version of standard anticoncentration results.
NON-MARKOVIAN STATE-DEPENDENT NETWORKS IN CRITICAL LOADING

□ We establish a heavy traffic limit theorem for the queue-length process in a critically loaded single class queueing network with state-dependent arrival and service rates. A distinguishing feature of our model is non-Markovian state dependence. The limit stochastic process is a continuous-path reflected process on the nonnegative orthant. We give an application to a generalized Jackson network with state-dependent rates.
How many consumers are rational

Abstract Rationality places strong restrictions on individual consumer behavior. This paper is concerned with assessing the validity of the integrability constraints imposed by standard utility maximization, arising in classical consumer demand analysis. More specifically, we characterize the testable implications of negative semidefiniteness and symmetry of the Slutsky matrix across a heterogeneous population without assuming anything on the functional form of individual preferences. Our approach employs nonseparable models and is centered around a conditional independence assumption, which is sufficiently general to allow for endogenous regressors. Using British household data, we show that rationality is an acceptable description for large parts of the population.
Rule-Based Evidence Accrual System For Image Understanding

The main function of an evidence accrual system for image understanding is to sequentially update information on scene objects based on new sensor data or on non-sensory information such as intelligence. This paper presents a concept for sequentially updating information on scene objects. Scene objects and background (clutter) are represented by attributed relational graphs in which nodes represent objects of interest and arcs represent inter-object relations. Dynamic recognition/identification of nodes is acomplished by a belief/disbelief measure. Our experimental results with infrared images show improvements in natural scene object recognition over traditional image processing methods.
An artificial neural net Viterbi decoder

The Viterbi algorithm is a maximum likelihood means for decoding convolutional codes and has thus played an important role in applications ranging from satellite communications to cellular telephony. In the past, Viterbi decoders have usually been implemented using digital circuits. The speed of these digital decoders is directly related to the amount of parallelism in the design. As the constraint length of the code increases, parallelism becomes problematic due to the complexity of the decoder. In this paper an artificial neural network (ANN) Viterbi decoder is presented. The ANN decoder is significantly faster than comparable digital-only designs due to its fully parallel architecture. The fully parallel structure is obtained by implementing most of the Viterbi algorithm using analog neurons as opposed to digital circuits. Several modifications to the ANN decoder are considered, including an analog/digital hybrid design that results in an extremely fast and efficient decoder. The ANN decoder requires one-sixth the number of transistors required by the digital decoder. The connection weights of the ANN decoder are either +1 or -1, so weight considerations in the implementation are eliminated. This, together with the design's modularity and local connectivity, makes the ANN Viterbi decoder a natural fit for VLSI implementation. Simulation results are provided to show that the performance of the ANN decoder matches that of an ideal Viterbi decoder.
Gift taxes and lifetime transfers: time series evidence

The tax treatment of lifetime transfers was altered on a number of occasions since the enactment of gift tax six decades ago. Trends in gifts by the wealthy show a dramatic response to these changes. In this paper, I examine this trend and gauge its response to taxes, transitory and permanent, over a period of 65 years. Results suggest that gifts are highly elastic with respect to taxes, particularly in the short run. Tax minimization seems to be an important consideration in the timing of intergenerational transfers. Published by Elsevier B.V. JEL classification: D19; H31
Modeling of Deposition Process in Liquid Fuels

The thermal stability of jet fuels results from a complex set of chemical reactions, and the deposition process is further complicated by physical mechanisms such as agglomeration and solvation. Although a vast amount of experimental data has been obtained by several researchers, the specific mechanisms responsible for thermal degradation of fuels and the consequent deposit-formation process are still largely unknown. This is primarily due to the fact that the fluid flow and the heat transfer which influence the deposition process vary significantly from experiment to experiment. It is thought that Computational Fluid Dynamics with Chemistry (CFDC) models can be used to correlate the data obtained from a number of experiments and, thereby, explore this large data base to aid the understanding of the deposition phenomenon. The success of this approach depends on the accuracy of the global-chemistry models used in the CFDC codes. Recent experiments on blended fuel prepared by mixing a hydrotreated fuel with...
Supraglacial and proglacial valleys on Amazonian Mars

Abundant evidence exists for glaciation being an important geomorphic process in the mid-latitude regions of both hemispheres of Mars, as well as in specific environments at near-equatorial latitudes, such as along the western flanks of the major Tharsis volcanoes. Detailed analyses of glacial landforms (lobate-debris aprons, lineated valley fill, concentric crater fill, viscous flow features) have suggested that this glaciation was predominantly cold-based. This is consistent with the view that the Amazonian has been continuously cold and dry, similar to conditions today. We present new data based on a survey of images from the Context Camera (CTX) on the Mars Reconnaissance Orbiter that some of these glaciers experienced limited surface melting, leading to the formation of small glaciofluvial valleys. Some of these valleys show evidence for proglacial erosion (eroding the region immediately in front of or adjacent to a glacier), while others are supraglacial (eroding a glacier’s surface). These valleys formed during the Amazonian, consistent with the inferred timing of glacial features based on both crater counts and stratigraphic constraints. The small scale of the features interpreted to be of glaciofluvial origin hindered earlier recognition, although their scale is similar to glaciofluvial counterparts on Earth. These valleys appear qualitatively different from valley networks formed in the Noachian, which can be much longer and often formed integrated networks and large lakes. The valleys we describe here are also morphologically distinct from gullies, which are very recent fluvial landforms formed during the last several million years and on much steeper slopes (∼20–30° for gullies versus ≪10° for the valleys we describe). These small valleys represent a distinct class of fluvial features on the surface of Mars (glaciofluvial); their presence shows that the hydrology of Amazonian Mars is more diverse than previously thought.
Dynamic optimization of dissipative PDE systems using nonlinear order reduction

In this work, we propose a computationally efficient method for the solution of dynamic constraint optimization problems arising in the context of spatially-distributed processes governed by highly-dissipative nonlinear partial differential equations (PDEs). The method is based on spatial discretization using combination of the method of weighted residuals with spatially-global basis functions and approximate inertial manifolds. We use the Kuramoto-Sivashinsky equation, a model that describes incipient instabilities in a variety of physical and chemical systems, to demonstrate the implementation and evaluate the effectiveness of the proposed optimization method.
Full-spectral color calculations in realistic image synthesis

The standard RGB color model manifests color errors when rendering or imaging metameric objects. In this article, we review some alternative color representation methods for accurate color image synthesis.
RSNA Board of Directors develops a 3-year strategic plan.

At a special strategic planning retreat held January 26–28, 2002, the Board of Directors and the executive staff of the Radiological Society of North America (RSNA) met to develop a strategic plan for the next 3 years. The plan is designed make the Society more effective in meeting the needs of its membership and the radiologic community at large. It is also intended to make the best possible use of the RSNA’s resources, both financial and human, now and in the future. The Board formally approved the plan at its February meeting and charged specific staff members, RSNA editors, RSNA committees, and Board members with the task of implementing each of its goals. The members of the RSNA Board thought it was important to develop a strategic plan for all of the Society’s activities, not just selected ones. Prior to the planning retreat, the senior staff of the RSNA had developed briefing papers on a wide range of topics relevant to the Society and its members. The Board then reviewed these papers and selected what they believed to be the top eight topics for immediate attention. The Board also reviewed a model planning process developed by consultant John F. Schlegel, who served as facilitator for the strategic planning retreat. Vision, Mission, and Values
An approach to evaluate the general performance of stand-alone wind/photovoltaic generating systems

This paper reports the development of a computer approach for evaluating the general performance of stand-alone wind/photovoltaic generating systems. Simple models for different system components are developed, integrated, and used to predict the behavior of generating systems based on available wind/solar and load data. The model is useful for evaluating the performance of stand-alone generating systems and gaining a better insight in the component sizes needed before they are built. Simulation results are presented for performance evaluation of a stand-alone generating system that has been previously designed to supply the average power demand of a typical residential house. An electric water heater model is used as a dump load, and the excess available wind/solar-generated power is used to heat the water. The heated water is used as the inlet water to the main house water heater, which is assumed to be nonelectric. It is shown that this strategy can be effective in reducing the amount of fuel used by the main residential water heater.
COHERENT STATES AND THE QUANTIZATION OF (1+1)-DIMENSIONAL YANG–MILLS THEORY

This paper discusses the canonical quantization of (1+1)-dimensional Yang–Mills theory on a spacetime cylinder from the point of view of coherent states, or equivalently, the Segal–Bargmann transform. Before gauge symmetry is imposed, the coherent states are simply ordinary coherent states labeled by points in an infinite-dimensional linear phase space. Gauge symmetry is imposed by projecting the original coherent states onto the gauge-invariant subspace, using a suitable regularization procedure. We obtain in this way a new family of "reduced" coherent states labeled by points in the reduced phase space, which in this case is simply the cotangent bundle of the structure group K. The main result explained here, obtained originally in a joint work of the author with B. Driver, is this: The reduced coherent states are precisely those associated to the generalized Segal–Bargmann transform for K, as introduced by the author from a different point of view. This result agrees with that of K. Wren, who uses a different method of implementing the gauge symmetry. The coherent states also provide a rigorous way of making sense out of the quantum Hamiltonian for the unreduced system. Various related issues are discussed, including the complex structure on the reduced phase space and the question of whether quantization commutes with reduction.
Intervening variables and constraint approximations in safety index and failure probability calculations

The emphasis of this paper is on developing suitable intervening variables and constraint approximations for structural reliability analysis. Traditionally, these procedures are used in structural optimization, whereas this research work adopts these concepts to safety index and failure probability computations. The use of these concepts enables the development of an efficient and stable iteration algorithm for identifying the most probable failure points (MPPs) of the limit state functions. An approximate second-order failure probability is calculated at this MPP with no extra computations of the limit state function and gradients. The efficiency and accuracy of the proposed algorithm are demonstrated by several examples with highly nonlinear, complex, explicit/implicit performance functions.
High field magnet R&D in the USA

Accelerator magnet technology is currently dominated by the use of NbTi superconductor. New and more demanding applications for superconducting accelerator magnets require the use of alternative materials. Several programs in the US are taking advantage of recent improvements in Nb/sub 3/Sn to develop high field magnets for new applications. Highlights and challenges of the US R&D program are presented along with the status of conductor development. In addition, a new R&D focus, the US Accelerator Research Program, will be discussed.
Highway overhead structure detection using video image sequences

A radar-based forward collision warning system has a limitation of not being able to distinguish a stopped vehicle from the false alarms caused by highway overhead structures. In this paper, we describe a system that detects the presence of overhead structures based on video images from an in-vehicle camera. The system also estimates the height and the distance of the structures to the host vehicle, which can be used to help reject false alarms in the radar detections caused by overhead structures. Our system uses a unique horizontal edge projection (HEP) as the primary feature for the detection of the overhead structures, which is computationally simple and robust to noise. Image vertical motion compensation and HEP tracking algorithms are developed to establish the HEP tracks of trajectories of the overhead structures in the image sequence. A least-squares algorithm is presented for the estimation of structure height and distance to the host vehicle using the HEP tracks. Experiments using real image sequences are presented.
Highlights of current research involving superoxide and perhydroxyl radicals in aqueous solutions.

SummarySelected topics of current research on HO2/O−2 radical reactions in aqueous solutions are described. The subject is introduced by a brief review of the fundamental background chemistry of HO2/O−2, including a description of the rates and mechanisms of formation and decay as well as their spectral properties, current research on self-exchange rates, etc. This is followed by examples of their reactivity with simple metal complexes of iron, manganese and copper and extended to some biological significant metal-containing systems such as porphyrins, haem enzymes and superoxide dismutases. Some recent results on the interaction of these oxy-radicals with antioxidants, specifically vitamin C and E, are discussed. A brief review of some topical chemistry describing HO2/O−2 involvement in atmospheric and aquatic chemistry is given. Finally, some new trends in the areas of heterogeneous catalysis and reactor chemistry that involve these species are described.
Evaluating anti-poverty programs

The paper critically reviews the methods available for the ex-post counterfactual analysis of programs that are assigned exclusively to individuals, households or locations. The discussion covers both experimental and non- experimental methods (including propensity-score matching, discontinuity designs, double and triple differences and instrumental variables). Two main lessons emerge: Firstly, despite the claims of advocates, no single method dominates; rigorous, policy-relevant evaluations should be open-minded about methodology. Secondly, future efforts to draw more useful lessons from evaluations will call for more policy-relevant measures and deeper explanations of measured impacts than are possible from the classic ("black box") assessment of mean impact.
Mapping the terrain of public service quality improvement: twenty-five years of trends and practices in the United States

The quality movement in the United States has been characterized as an impetus for organizational effectiveness and responsiveness since the late 1970s. ‘Quality’ can be a subjective term as each organization has its own definition and boundaries. Three emphases are evident in the field of quality improvement: quality circles, total quality management, and citizen satisfaction. Practices of quality improvement in the public sector have been driven by demands from citizens for more effective services, outcomes that require the implementation of suitable quality models and standards.Points for practitionersThis article presents major intellectual trends in the practice of service quality improvement. Practitioners will be able to comprehend the most fundamental concepts of ‘what is public service quality improvement’. Practitioners will also obtain useful insights into defining quality criteria and assessing organizational improvement models based on substantive principles of quality management for promotin...
Maximum-entropy expectation-maximization algorithm for image processing and sensor networks

In this paper, we propose a maximum-entropy expectation-maximization algorithm. We use the proposed algorithm for density estimation. The maximum-entropy constraint is imposed in order to ensure smoothness of the estimated density function. The exact derivation of the maximum-entropy expectation-maximization algorithm requires determination of the covariance matrix combined with the maximum entropy likelihood function, which is difficult to solve directly. We therefore introduce a new lower-bound for the EM algorithm derived by using the Cauchy-Schwartz inequality to obtain a suboptimal solution. We use the proposed algorithm for function interpolation and image segmentation. We propose the use of the EM algorithm for image recovery from randomly sampled data and signal reconstruction from randomly scattered sensors. We further propose to use our approach to maximum-entropy expectation-maximization (MEEM) in all of these applications. Computer simulation experiments are used to demonstrate the performance of our algorithm in comparison to existing methods.
Efficient canonical form for Boolean matching of complex functions in large libraries

A new algorithm is developed which transforms the truth table or implicant table of a Boolean function into a canonical form under any permutation of inputs. The algorithm is used for Boolean matching for large libraries that contain cells with large numbers of inputs and implicants. The minimum cost canonical form is used as a unique identifier for searching for the cell in the library. The search time is nearly constant if a hash table is used for storing the cells' canonical representations in the library. Experimental results on more than 100000 gates confirm the validity and feasible runtime of the algorithm.