cssi/SciSciGPT-SciSciNet huggingface dataset:
Interstellar dust close to the Sun

The low density interstellar medium (ISM) close to the Sun and inside of the heliosphere provides a unique laboratory for studying interstellar dust grains. Grain characteristics in the nearby ISM are obtained from observations of interstellar gas and dust inside of the heliosphere and the interstellar gas towards nearby stars. Comparison between the gas composition and solar abundances suggests that grains are dominated by olivines and possibly some form of iron oxide. Measurements of the interstellar Ne/O ratio by the Interstellar Boundary Explorer spacecraft indicate that a high fraction of interstellar oxygen in the ISM must be depleted onto dust grains. Local interstellar abundances are consistent with grain destruction in ~150 km s−1 interstellar shocks, provided that the carbonaceous component is hydrogenated amorphous carbon and carbon abundances are correct. Variations in relative abundances of refractories in gas suggest variations in the history of grain destruction in nearby ISM. The large observed grains, > 1 μm, may indicate a nearby reservoir of denser ISM. Theoretical three-dimensional models of the interaction between interstellar dust grains and the solar wind predict that plumes of ~0.18 μm dust grains form around the heliosphere.
Synthesis of Indenes by the Palladium-Catalyzed Carboannulation of Internal Alkynes

A number of highly substituted indenes have been prepared in good yields by treating functionally substituted aryl halides with various internal alkynes in the presence of a palladium catalyst. The reaction is believed to proceed by regioselective arylpalladation of the alkyne and subsequent nucleophilic displacement of the palladium in the resulting vinylpalladium intermediate.
Synthesis of Diaryl Sulfones at Room Temperature: Cu-Catalyzed Cross-Coupling of Arylsulfonyl Chlorides with Arylboronic Acids

An efficient and convenient method for the synthesis of diaryl sulfones was developed through the Cu-catalyzed cross-couplings of arylsulfonyl chlorides and arylboronic acids at room temperature in open air. This method is characterized by the use of inexpensive and readily available catalyst and substrates, mild reaction conditions, wide functionality tolerance, short reaction times for most substrates, and moderate to good yields.
Using the revenues from congestion pricing

The economic theory behind congestion pricing relies on using the revenues to help compensate highway users. But can practical methods of using revenues come close to achieving this compensation, and still have salient appeal to important political groups? This paper investigates the possibilities for designing a package of revenue uses that can achieve these twin goals. The suggested approach returns two-thirds of the revenues to travelers through travel allowances and tax reductions, and uses the rest to improve transportation throughout the area, including affected business centers. By replacing regressive sales and fuel taxes, this approach offsets the tendency of the prices alone to have a regressive distributional impact. By lowering taxes, funding new highways, improving transit, and upgrading business centers, the package provides inducements for support from several key interest groups. The potential amounts of money involved are discussed using nationwide data, and in more detail using a case study of ubiquitous facility pricing throughout the Los Angeles region. Illustrative calculations of the effects on various individuals confirm that such a package can create net benefits for a wide spectrum of people and interest groups.
Astrophysics: a burst of new ideas.

Gigantic cosmological γ-ray bursts have fallen into a dichotomy of long and short bursts, each with a very different origin. The discovery of an oddball burst calls for a rethink of that classification.
Triad case study: Former small arms training range

The U.S. Army Corps of Engineers (USACE) used the Triad approach to expedite site characterization of contaminated soil at the Former Small Arms Evergreen Infiltration Training Range in Fort Lewis, Washington. The characterization was designed to determine if surface soils contain significant concentrations of metals, with the focus on collecting sufficient data for determining appropriate future actions (i.e., risk analysis or soil remediation). A dynamic sampling and analytical strategy based on rapid field based analytical methods was created in order to streamline site activities and save resources while increasing confidence in remediation decisions. Concurrent analysis of soil samples during the Demonstration of Method Applicability (DMA) used both field portable X-ray Fluorescence (FPXRF) and laboratory methodologies to establish a correlation between FPXRF and laboratory data. Immediately following the DMA, contaminated soil from the impact berm was delineated by collecting both FPXRF data and fixed-laboratory confirmation samples. The combined data set provided analytical results that allowed for revisions to the conceptual site model for the range and directed additional sample collection activities to more clearly determine the extent and distribution of soil contamination.
Using Student Test Scores to Measure Principal Performance

Expansion of the use of student test score data to measure teacher performance has fueled recent policy interest in using those data to measure the effects of school administrators as well. However...
tBu3P‐Coordinated 2‐Phenylaniline‐Based Palladacycle Complexes as Precatalyst for Pd‐Catalyzed Coupling Reactions of Aryl Halides with Polyfluoroarenes by a C–H Activation Strategy

tBu3P-Coordinated 2-phenylaniline-based palladacycle complex was demonstrated to be an efficient precatalyst for Pd-catalyzed coupling reactions of aryl halides with polyfluoroarenes via C-H activation strategy. The readily accessibility and easy handling nature of tBu3P- coordinated 2-aminobiphenyl-based palladacycle complex and the high yields of the reaction makes tBu3P-coordinated 2-aminobiphenyl-based palladacycle complex an attractive precatalyst for the cross-coupling reaction of aryl halides with polyfluoroarenes.
Irrationality and intertemporal choice in early neoclassical thought

Early neoclassical economists presumed an element of irrationality in the context of intertemporal decision making. W.S. Jevons, Irving Fisher, Alfred Marshall, and A.C. Pigou observed a preference for present over future consumption, and each took this as evidence that consumer ‘foresight’ or ‘will power’ was defective. The labouring classes were said to discount future consumption to reflect uncertainty, and such discounting is regarded as ‘rational.’ But each of these economists focused on an additional, and purportedly ‘irrational,’ reason for discounting: ‘impatience.’ Consumers are thus said to make persistent miscalculations when it comes to decisions involving time. Irrationalite et choix intertemporel dans les debuts de la pensee neo-classique. Les premiers economistes neo-classiques presumaient qu'il y avait un brin d'irrationalite dans le processus de decision intertemporel. W.S. Jevons, Irving Fisher, Alfred Marshall et A.C. Pigou ont observe une certaine preference de la consommation presente par rapport a la consommation future et en ont deduit que le consommateur manquait de ‘prevoyance’ et de ‘volonte.’ On suggerait que les classes travailleuses escomptaient leur consommation future a cause de l'incertitude - ce qui etait conside comme rationnel. Mais chacun de ces economistes faisait aussi appel a une raison additionnelle pour escompter la consommation future - l'impatience - un motif juge irrationnel. On en concluait que les consommateurs faisaient des erreurs persistantes de calcul quand ils prenaient des decisions intertemporelles.
Progress in understanding jointing over the past century

Joints are the most common result of brittle fracture of rock in the Earth's crust. They control the physiography of many spectacular landforms and play an important role in the transport of fluids. In its first century, the Geological Society of America Bulletin has published a significant number of papers on joints and jointing. One hundred years ago, there were lively debates in the literature about the origin of joints, and detailed descriptions of joints near the turn of the century catalogued most geometric features that we recognize on joints today. In the 1920s, theories relating joint orientation to the tectonic stress field and to other geologic structures led to a proliferation of data on the strike and dip of joints in different regions. The gathering of orientation data dominated work on joints for the next 50 yr. In the 1960s, key papers re-established the need to document surface textures, determine age relations, and measure relative displacements across joints in order to interpret their origins. At about this time, fundamental relationships from the fields of continuum and fracture mechanics were first used to understand the process of jointing. In the past two decades, we have witnessed an effort to use field data to interpret the kinematics of jointing and to understand the initiation, propagation, interaction, and termination of joints. Theoretical methods have been developed to study the evolution of joint sets and the mechanical response of a jointed rock mass to tectonic loading. Although many interesting problems remain to be explored, a sound conceptual and theoretical framework is now available to guide research into the next century.
High-sensitivity detection of trace gases using dynamic photoacoustic spectroscopy

Lincoln Laboratory of Massachusetts Institute of Technology has developed a technique known as dynamic photoacoustic spectroscopy (DPAS) that could enable remote detection of trace gases via a field-portable laser-based system. A fielded DPAS system has the potential to enable rapid, early warning of airborne chemical threats. DPAS is a new form of photoacoustic spectroscopy that relies on a laser beam swept at the speed of sound to amplify an otherwise weak photoacoustic signal. We experimentally determine the sensitivity of this technique using trace quantities of SF 6 gas. A clutter-limited sensitivity of ∼100 ppt is estimated for an integration path of 0.43 m. Additionally, detection at ranges over 5 m using two different detection modalities is demonstrated: a parabolic microphone and a laser vibrometer. Its utility in detecting ammonia emanating from solid samples in an ambient environment is also demonstrated.
Active Beam Cross-Sectional Modeling

A finite-element based analysis formodeling initially twisted and curved active composite beams with embedded anisotropic actuation is presented. It is derived from three-dimensional electroelastic...
Primality Test Via Quantum Factorization

We consider a probabilistic quantum implementation of a variation of the Pocklington–Lehmer N - 1 primality test using Shor's algorithm. O (log3 N loglog N logloglog N) elementary q-bit operations are required to determine the primality of a number N, making it (asymptotically) the fastest known primality test. Thus, the potential power of quantum mechanical computers is once again revealed.
Pitting Corrosion of Metals A Review of the Critical Factors

Pitting corrosion is localized accelerated dissolution of metal that occurs as a result of a breakdown of the otherwise protective passive film on the metal surface. This paper provides an overview of the critical factors influencing the pitting corrosion of metals. The phenomenology of pitting corrosion is discussed, including the effects of alloy composition, environment, potential, and temperature. A summary is then given of studies that have focused on various stages of the pitting process, including breakdown of the passive film, metastable pitting, and pit growth.
The College Life Experiences of African American Women Athletes

The present study provides a descriptive analysis of four areas of African American women student athletes' college life experiences: academic performance; alienation and abuse; perceived social advantage as the result of athletics; and life satisfaction. Multivariate comparisons were made between the four areas of college life experiences of 154 African American women student athletes and 793 White women student athletes, 250 African American women nonathletes, and 628 African American men student athletes from a national sample of 39 NCAA Division I universities. Overall, African American women student athletes are performing adequately academically, integrating socially within the university, perceiving some social advantage as the result of being athletes, and are fairly satisfied with their life. Their experiences seem most consistent with African American women nonathletes. Results are discussed in the context of potential policy recommendations as well as the need for more research on this particular population.
Beam profile monitors in the NLCTA

The transverse current profile in the Next Linear Collider Test Accelerator (NLCTA) electron beam can be monitored at several locations along the beam line by means of profile monitors. These consist of insertable phosphor screens, light collection and transport systems, CID cameras, a frame-grabber, and PC and VAX based image analysis software. In addition to their usefulness in tuning and steering the accelerator, the profile monitors are utilized for emittance measurement. A description of these systems and their performance is presented.
Carbon and Climate System Coupling on Timescales from the Precambrian to the Anthropocene

Over a range of geological and historical timescales, warmer climate conditions are associated with higher atmospheric levels of CO2, an important climate-modulating greenhouse gas. Coupled carbon-climate interactions have the potential to introduce both stabilizing and destabilizing feedback loops into Earth's system. Here we bring together evidence on the dominant climate, biogeochemical and geological processes organized by timescale, spanning interannual to centennial climate variability, Holocene millennial variations and Pleistocene glacial-interglacial cycles, and million-year and longer variations over the Precambrian and Phanerozoic. Our focus is on characterizing, and where possible quantifying, internal coupled carbon-climate system dynamics and responses to external forcing from tectonics, orbital dynamics, catastrophic events, and anthropogenic fossil-fuel emissions. One emergent property is clear across timescales: atmospheric CO2 can increase quickly, but the return to lower levels through ...
Duality for Legendrian contact homology

As in smooth knot theory, a fundamental problem in Legendrian knot theory is to find effective invariants and to understand their structure and meaning. Bennequin [1] initiated the modern study of Legendrian knots by introducing two “classical” invariants: the Thurston–Bennequin number (which measures the difference between the framing of a knot coming from the contact planes and the Seifert surface framing) and the rotation number (which measures the twisting of the tangent to the knot inside the contact planes with respect to a suitable trivialization). These two invariants suffice to classify Legendrian knots in the standard contact structure on R when the underlying smooth knot type is the unknot (Eliashberg and Fraser [8]), a torus knot or the figure eight knot (Etnyre and Honda [11]) or a cable link (Ding and Geiges [5]).
Artificial intelligence framework for simulating clinical decision-making: A Markov decision process approach

Objective: In the modern healthcare system, rapidly expanding costs/complexity, the growing myriad of treatment options, and exploding information streams that often do not effectively reach the front lines hinder the ability to choose optimal treatment decisions over time. The goal in this paper is to develop a general purpose (non-disease-specific) computational/artificial intelligence (AI) framework to address these challenges. This framework serves two potential functions: (1) a simulation environment for exploring various healthcare policies, payment methodologies, etc., and (2) the basis for clinical artificial intelligence - an AI that can ''think like a doctor''. Methods: This approach combines Markov decision processes and dynamic decision networks to learn from clinical data and develop complex plans via simulation of alternative sequential decision paths while capturing the sometimes conflicting, sometimes synergistic interactions of various components in the healthcare system. It can operate in partially observable environments (in the case of missing observations or data) by maintaining belief states about patient health status and functions as an online agent that plans and re-plans as actions are performed and new observations are obtained. This framework was evaluated using real patient data from an electronic health record. Results: The results demonstrate the feasibility of this approach; such an AI framework easily outperforms the current treatment-as-usual (TAU) case-rate/fee-for-service models of healthcare. The cost per unit of outcome change (CPUC) was $189 vs. $497 for AI vs. TAU (where lower is considered optimal) - while at the same time the AI approach could obtain a 30-35% increase in patient outcomes. Tweaking certain AI model parameters could further enhance this advantage, obtaining approximately 50% more improvement (outcome change) for roughly half the costs. Conclusion: Given careful design and problem formulation, an AI simulation framework can approximate optimal decisions even in complex and uncertain environments. Future work is described that outlines potential lines of research and integration of machine learning algorithms for personalized medicine.
Computing algebraic numbers of bounded height

We describe an algorithm for listing all elements of bounded height in a given number field.
Arithmetic differential equations on GL_n, III Galois groups

Differential equations have arithmetic analogues (Buium in Arithmetic differential equations, Mathematical Surveys and Monographs, vol 118. American Mathematical Society, Providence 2005) in which derivatives are replaced by Fermat quotients; these analogues are called arithmetic differential equations, and the present paper is concerned with the “linear” ones. The equations themselves were introduced in a previous paper (Buium and Dupuy, in Arithmetic differential equations on $$GL_{n}$$ , II: arithmetic Lie–Cartan theory, arXiv:1308.0744 ). In the present paper we deal with the solutions of these equations as well as with the Galois groups attached to the solutions.
A Proof of a Non-Commutative Central Limit Theorem by the Lindeberg Method

A Central Limit Theorem for non-commutative random variables is proved using the Lindeberg method. The theorem is a generalization of the Central Limit Theorem for free random variables proved by Voiculescu. The Central Limit Theorem in this paper relies on an assumption which is weaker than freeness.
Sources of Slow Growth in African Economies

This paper offers some econometric evidence on the sources of slow growth in Sub-Saharan Africa. The evidence suggests that the continent’s slow growth can be explained in an international cross-country framework, without the need to invoke a special explanation unique to Sub-Saharan Africa. We find that poor economic policies have played an especially important role in the slow growth, most importantly Africa’s lack of openness to international markets. In addition, geographical factors such as lack of access to the sea and tropical climate have also contributed to Africa’s slow growth.
Integrated genetic algorithm and its applications for construction resource optimization

Construction project resource scheduling problems have been interesting and challenging subjects of extensive research for several decades in the optimization study area in order to put them in practical application. Recently, the integrated genetic algorithm rather than the stand-alone GA is being increasingly applied to solve the problems. An adaptive hybrid genetic algorithm search simulator (AHGASS) for resource scheduling problems has been developed in the previous stage of this research. Previous work outlined the strategies and practical procedures for the algorithm development, but did not deal with algorithm performance with regard to algorithm runtime, especially against runtime used in generating optimality. Since the major drawback of using GA is a great length of time required, it is meaningful to investigate the significance in algorithm runtime between AHGASS and optimality. To address this issue, this paper attempts to investigate the difference in algorithm performance with regard to algorithm runtime.
In search of the elusive flow field

A specific set of problems must be overcome before an optical-flow field can be derived from an image sequence. These problems are discussed and an outline of a scheme for overcoming these obstacles is presented. A 2-D motion sensor is presented which is capable of measuring edge velocity in twelve separate directions at any point in the image. However, because of the aperture problem, the sensors can only determine the velocity component in the direction orthogonal to the edge. A second stage which uses a cosine-weighted voting scheme is used to derive the true flow field from the edge velocities. The whole system is based on a parallel network of connections and weights and is potentially a very fast method of obtaining the 2-D flow field. >
CP violation in the B meson system: recent experimental results

Recent experimental results on CP violation in the study of B meson decays are reviewed. The emphasis is put on the recent measurements of the CP parameter sin2fl by the BABAR and BELLE experiments at asymmetric B factories, which establish for the flrst time CP violation in the B meson system. L decays thirty seven years ago (1), while the last flfteen years have been rich in experimental and theoretical developments in Heavy Flavor physics (2). The consistency of the experimental results with the general scheme of charged weak interactions and CP violation in the Standard Model of particle physics is highly non-trivial. Now is the time to challenge the model experimentally in its prediction of large CP violation efiects in the B meson system. This paper gives an overview of the present experimental knowledge on the subject. We start with a status report on the new generation ofB factory experiments, followed by an introduction to the B 0 B 0 system and the CKM matrix, and an overview of present experimental constraints on the Unitarity Triangle from CP-violating K and CP-conserving B observations. We then review in turn searches for CP violation in the B system: direct CP violation, CP violation in B 0 B 0 mixing and, flnally, CP violation in the interference between mixing and decay, with an emphasis on the recent sin2fl measurements by BABAR and BELLE. We conclude the review by an overview of experimental prospects in the domain.
Stronger security of authenticated key exchange

Recent work by Krawczyk [12] and Menezes [16] has highlighted the importance of understanding well the guarantees and limitations of formal security models when using them to prove the security of protocols. In this paper we focus on security models for authenticated key exchange (AKE) protocols. We observe that there are several classes of attacks on AKE protocols that lie outside the scope of the Canetti-Krawczyk model. Some of these additional attacks have already been considered by Krawczyk [12]. In an attempt to bring these attacks within the scope of the security model we extend the Canetti-Krawczyk model for AKE security by providing significantly greater powers to the adversary. Our contribution is a more compact, integrated, and comprehensive formulation of the security model. We then introduce a new AKE protocol called NAXOS and prove that it is secure against these stronger adversaries.
Nash Equilibrium and Welfare Optimality

If is a set of social alternatives, a social choice rule (SCR) assigns a subset of A to each potential profile of individuals' preferences over A, where the subset is interpreted as the set of 'welfare optima.' A game form (or 'mechanism') implements the social choice rule if, for any potential profile of preferences, (1) any welfare optimum can arise as a Nash equilibrium of the game form (implying, in particular, that a Nash equilibrium exists) and, (2) all Nash equilibria are welfare optimal. The main result of this paper establishes that any SCR that satisfies two properties - monotonicity and no veto power--can be implemented by a game form if there are three or more individuals. The proof is constructive.
Face-selective electrostatic control of hydrothermal zinc oxide nanowire synthesis

Rational control over the morphology and the functional properties of inorganic nanostructures has been a long-standing goal in the development of bottom-up device fabrication processes. We report that the geometry of hydrothermally grown zinc oxide nanowires can be tuned from platelets to needles, covering more than three orders of magnitude in aspect ratio (~0.1-100). We introduce a classical thermodynamics-based model to explain the underlying growth inhibition mechanism by means of the competitive and face-selective electrostatic adsorption of non-zinc complex ions at alkaline conditions. The performance of these nanowires rivals that of vapour-phase-grown nanostructures, and their low-temperature synthesis (<60 °C) is favourable to the integration and in situ fabrication of complex and polymer-supported devices. We illustrate this capability by fabricating an all-inorganic light-emitting diode in a polymeric microfluidic manifold. Our findings indicate that electrostatic interactions in aqueous crystal growth may be systematically manipulated to synthesize nanostructures and devices with enhanced structural control.
Combination Therapies Prevent the Neuropathic, Proinflammatory Characteristics of Bone Marrow in Streptozotocin-Induced Diabetic Rats

We previously showed that peripheral neuropathy of the bone marrow was associated with loss of circadian rhythmicity of stem/progenitor cell release into the circulation. Bone marrow neuropathy results in dramatic changes in hematopoiesis that lead to microvascular complications, inflammation, and reduced endothelial repair. This series of events represents early pathogenesis before development of diabetic retinopathy. In this study we characterized early alterations within the bone marrow of streptozotocin (STZ)-induced diabetic rats following treatments that prevent experimental peripheral neuropathy. We asked whether bone marrow neuropathy and the associated bone marrow pathology were reversed with treatments that prevent peripheral neuropathy. Three strategies were tested: inhibition of neutral endopeptidase, inhibition of aldose reductase plus lipoic acid supplementation, and insulin therapy with antioxidants. All strategies prevented loss of nerve conduction velocity resulting from STZ-induced diabetes and corrected the STZ-induced diabetes–associated increase of immunoreactivity of neuropeptide Y, tyrosine hydroxylase, and somatostatin. The treatments also reduced concentrations of interleukin-1β, granulocyte colony-stimulating factor, and matrix metalloproteinase 2 in STZ-induced diabetic bone marrow supernatant and decreased the expression of NADPH oxidase 2, nitric oxide synthase 2, and nuclear factor-κB1 mRNA in bone marrow progenitor cells. These therapies represent novel approaches to attenuate the diabetic phenotype within the bone marrow and may constitute an important therapeutic strategy for diabetic microvascular complications.
Specification techniques for data abstractions

The main purposes in writing this paper are to discuss the importance of formal specifications and to survey a number of promising specification techniques. The role of formal specifications both in proofs of program correctness, and in programming methodologies leading to programs which are correct by construction, is explained. Some criteria are established for evaluating the practical potential of specification techniques. The importance of providing specifications at the right level of abstraction is discussed, and a particularly interesting class of specification techniques, those used to construct specifications of data abstractions, is identified. A number of specification techniques for describing data abstractions are surveyed and evaluated with respect to the criteria. Finally, directions for future research are indicated.
Combined beamforming and space-time block coding with a sparse array antenna

We continue our investigation of joint beamforming and transmit diversity with space-time block coding. In particular, the performance of a four-element array antenna is considered, in the context of an indoor wireless communication system. The main contribution is to show that transmit diversity may be practically achieved, even with correlated beams produced by a sparse array antenna.
Protostar Mass due to Infall and Dispersal

The mass of a protostar is calculated from the infall and dispersal of an isothermal sphere in a uniform background. For high contrast between peak and background densities and for short dispersal time td, the accretion is self-limiting; gas beyond the core is dispersed before it accretes, and the protostar mass approaches a time-independent value of low mass. For lower density contrast and longer dispersal time, the accretion runs away; gas accretes from beyond the core, and the protostar mass approaches massive star values. The final protostar mass is approximately the initial gas mass whose free-fall time equals td. This mass matches the peak of the IMF for gas temperature 10 K, peak and background densities 106 and 103 cm?3, respectively, and td comparable to the core free-fall time tcore. The accretion luminosity exceeds 1 L? for 0.1 Myr, as in the Class 0 phase. For -->td/tcore = 0.4?0.8 and temperature 7-50 K, self-limiting protostar masses are 0.08-5 M?. These protostar and core masses have ratio -->0.4 ? 0.2, as expected if the core mass distribution and the initial mass function have the same shape.
Region-based incremental pruning for POMDPs

We present a major improvement to the incremental pruning algorithm for solving partially observable Markov decision processes. Our technique targets the cross-sum step of the dynamic programming (DP) update, a key source of complexity in POMDP algorithms. Instead of reasoning about the whole belief space when pruning the cross-sums, our algorithm divides the belief space into smaller regions and performs independent pruning in each region. We evaluate the benefits of the new technique both analytically and experimentally, and show that it produces very significant performance gains. The results contribute to the scalability of POMDP algorithms to domains that cannot be handled by the best existing techniques.
Asymmetric Mannich Synthesis of α-Amino Esters by Anion-Binding Catalysis

We report a scalable, one-pot Mannich route to enantioenriched α-amino esters by direct reaction of α-chloroglycine ester as a practical imino ester surrogate. The reaction is promoted by a chiral aminothiourea, which is proposed to operate cooperatively by generating an iminium ion by chloride abstraction and an enolate by deprotonation, followed by highly stereoselective C–C bond formation between both reactive intermediates associated non-covalently within the catalyst framework.
Marriage penalties in public programs: Social security's child-in-care widow(er) benefits

The Social Security program, like the federal income tax system, is not marriage neutral. Provisions in each public program, in effect, subsidize or penalize marriage. In this paper, we examine marriage penalties associated with Social Security's child-in-care benefi ts. This program provides fi nancial benefi ts to the minor or disabled children and spouse of a worker covered by Social Secu- rity in the event of the worker's death. Benefi ts to the widow(er) terminate upon remarriage, giving rise to marriage penalties. We document the size of these penalties, discuss their likely effects on marriage decisions, and measure the cost of repealing the termina- tion provision. Finally, because of the complex nature of the Social Security benefi t computations, we suggest that many widow(er)s may perceive larger penalties than actually exist. Providing more complete information to widow(er)s might encourage marriage, as individuals would realize that the penalties are not as large as they appear. We offer some practical suggestions on how the Social Security Administration could better inform widow(er)s as to the true size of the penalties.
Phenyl esters, preferred reagents for mono-acylation of polyamines in the presence of water

In the presence of water, several diamines and one triamine were mono-acylated at ambient to moderate temperatures using phenyl esters and a phenyl carbonate as acylation agents in good to excellent isolated yields. Both linear and cyclic polyamines were suitable substrates, and the acylating agents can be aryl and alkyl carboxylic acid esters.
Processor allocation on Cplant: achieving general processor locality using one-dimensional allocation strategies

The Computational Plant or Cplant is a commodity-based supercomputer under development at Sandia National Laboratories. This paper describes resource-allocation strategies to achieve processor locality for parallel jobs in Cplant and other supercomputers. Users of Cplant and other Sandia supercomputers submit parallel jobs to a job queue. When a job is scheduled to run, it is assigned to a set of processors. To obtain maximum throughput, jobs should be allocated to localized clusters of processors to minimize communication costs and to avoid bandwidth contention caused by overlapping jobs. This paper introduces new allocation strategies and performance metrics based on space-filling curves and one dimensional allocation strategies. These algorithms are general and simple. Preliminary simulations and Cplant experiments indicate that both space-filling curves and one-dimensional packing improve processor locality compared to the sorted free list strategy previously used on Cplant. These new allocation strategies are implemented in the new release of the Cplant System Software, Version 2.0, phased into the Cplant systems at Sandia by May 2002.
Prenatal Infection as a Risk Factor for Schizophrenia

Accumulating evidence suggests that prenatal exposure to infection contributes to the etiology of schizophrenia. This line of investigation has been advanced by birth cohort studies that utilize prospectively acquired data from serologic assays for infectious and immune biomarkers. These investigations have provided further support for this hypothesis and permitted the investigation of new infectious pathogens in relation to schizophrenia risk. Prenatal infections that have been associated with schizophrenia include rubella, influenza, and toxoplasmosis. Maternal cytokines, including interleukin-8, are also significantly increased in pregnancies giving rise to schizophrenia cases. Although replication of these findings is required, this body of work may ultimately have important implications for the prevention of schizophrenia, the elaboration of pathogenic mechanisms in this disorder, and investigations of gene-environment interactions.
Formalizing the gene centered view of evolution

A historical dispute in the conceptual underpinnings of evolution is the validity of the gene centered view of evolution. We transcend this debate by formalizing the gene centered view and establishing the limits on its applicability. We show that the gene-centered view is a dynamic version of the well known mean field approximation. It breaks down for trait divergence which corresponds to symmetry breaking in evolving populations.
Using Coupled Subspace Models for Reflectance/Illumination Separation

Spectral reflectance is an inherent material property which can be used for material identification tasks. We present a nonlinear algorithm for estimating surface spectral reflectance of the ground material using images acquired by an airborne sensor. The nonlinear algorithm separates the atmospheric and illumination effects from the measured spectral radiance corresponding to a single pixel in the image to recover the surface spectral reflectance. A low-dimensional subspace model for the reflectance spectra is used for the algorithm. The algorithm also considers the interdependence of the path radiance and illumination spectra by using a coupled subspace model. We have analyzed the accuracy of the algorithm over simulated and real 0.4-1.74-mum sensor radiance spectra.
Synthesis of 2H-indazoles via lewis acid promoted cyclization of 2-(phenylazo)benzonitriles

Lewis-acid promoted “coarctate” cyclization of 10 2-(phenylazo)benzonitrile derivatives furnishes the isoindazole ring system in ca. 65−95% yield. A plausible mechanism for this unusual transformation is proposed.
How attorneys question children about the dynamics of sexual abuse and disclosure in criminal trials.

Little is known about how the dynamics of sexual abuse and disclosure are discussed in criminal court. We examined how attorneys ask child witnesses in sexual abuse cases (N = 72, 6 -16 years of age) about their prior conversations, both with suspects and with disclosure recipients. Prosecutors' questions were more open-ended than defense attorneys, but most questions asked by either attorney were yes/no questions, and children tended to provide unelaborated responses. Prosecutors were more inclined to ask about children's prior conversations with suspects than defense attorneys, but focused on the immediate abuse rather than on grooming behavior or attempts to silence the victim. Prosecutors were also more inclined to ask about children's motives for disclosing or for failing to disclose than defense attorneys, but in most cases, failed to ask. Both types of attorney asked children about prior disclosures, although defense attorneys were more inclined to ask children to recall specific content in particular disclosures. On average, children were asked about five disclosure recipients, and denied disclosing some information in 93% of cases. Attorneys exhibited little sensitivity to the age of the child in selecting their questions. The implications of the results for improving the process by which abuse cases are tried in court are discussed.
Lacunary sections for locally compact groupoids

It is proved that every second countable locally Hausdorff and locally compact continuous groupoid has a Borel set of units that meets every orbit and is what is called ‘lacunary’, a property that implies that the intersection with every orbit is countable.
Synthesis of Substituted 3-Hydroxy-2-Furanone Derivatives via an Unusual Enolate Wittig Rearrangement/Alkylative Cyclization Sequence

Treatment of methyl O-(alkynylmethyl) glycolate derivatives with dialkylboron triflates and Hunig’s base leads to the formation of highly substituted 3-hydroxy-2-furanone derivatives. The transformations appear to proceed via an unusual mechanism involving initial 2,3-Wittig rearrangement of a boron ester enolate followed by an alkylative cyclization reaction that leads to incorporation of an alkyl group from the boron reagent into the product.
Reductive alkylation on a solid phase: Synthesis of a piperazinedione combinatorial library

Abstract The synthesis of a prototype trisubstituted piperazinedione combinatorial library of 1,000 compounds has been achieved from three precursor sets — two sets of ten α-amino acids and one set of ten aldehydes. A sodium triacetoxyborohydride-mediated reductive alkylation was crucial to the success of the multi-step synthesis on resin. This protocol represents a new method to augment compound files rapidly with novel heterocyclic entities for high-speed screening.
Bandwidth scaling and spectral flatness enhancement of optical frequency combs from phase-modulated continuous-wave lasers using cascaded four-wave mixing

We introduce a new cascaded four-wave mixing technique that scales up the bandwidth of frequency combs generated by phase modulation of a continuous-wave (CW) laser while simultaneously enhancing the spectral flatness. As a result, we demonstrate a 10 GHz frequency comb with over 100 lines in a 10 dB bandwidth in which a record 75 lines are within a flatness of 1 dB. The cascaded four-wave mixing process increases the bandwidth of the initial comb generated by the modulation of a CW laser by a factor of five. The broadband comb has approximately quadratic spectral phase, which is compensated upon propagation in single-mode fiber, resulting in a 10 GHz train of 940 fs pulses.
Bayesian Estimation of Hardness Ratios: Modeling and Computations

A commonly used measure to summarize the nature of a photon spectrum is the so-called hardness ratio, which compares the numbers of counts observed in different passbands. The hardness ratio is especially useful to distinguish between and categorize weak sources as a proxy for detailed spectral fitting. However, in this regime classical methods of error propagation fail, and the estimates of spectral hardness become unreliable. Here we develop a rigorous statistical treatment of hardness ratios that properly deals with detected photons as independent Poisson random variables and correctly deals with the non-Gaussian nature of the error propagation. The method is Bayesian in nature and thus can be generalized to carry out a multitude of source-population-based analyses. We verify our method with simulation studies and compare it with the classical method. We apply this method to real-world examples, such as the identification of candidate quiescent low-mass X-ray binaries in globular clusters and tracking the time evolution of a flare on a low-mass star.
SPHRAY : a smoothed particle hydrodynamics ray tracer for radiative transfer

We introduce the publicly available code sphray, a smoothed particle hydrodynamics (SPH) ray tracer designed to solve the 3D, time-dependent, radiative transfer equation for cosmological density fields. The SPH nature of sphray makes the incorporation of separate hydrodynamics and gravity solvers very natural. sphray relies on a Monte Carlo (MC) ray-tracing scheme that does not interpolate the SPH particles on to a grid but instead integrates directly through the SPH kernels. Given an arbitrary (series of) SPH density field(s) and a description of the sources of ionizing radiation, the code will calculate the non-equilibrium ionization and temperature state of hydrogen (H i, H ii) and helium (He i, He ii, He iii). The sources of radiation can include point-like objects, diffuse recombination radiation, and a background field from outside the computational volume. The MC ray-tracing implementation allows for the quick introduction of new physics and is parallelization-friendly. A quick Axis Aligned Bounding Box (AABB) test taken from computer graphics applications allows for the acceleration of the ray-tracing component. We present the algorithms used in sphray and verify the code by performing the test problems detailed in the recent Radiative Transfer Comparison Project of Iliev et. al. The source code for sphray and example SPH density fields are made available on a companion website (http://www.sphray.org).
Experimental study of the wake behind a surface-piercing cylinder for a clean and contaminated free surface

This experimental investigation into the nature of free-surface flows was to study the effects of surfactants on the wake of a surface-piercing cylinder. A better understanding of the process of vorticity generation and conversion at a free surface due to the absence or presence of surfactants has been gained. Surfactants, or surface contaminants, have the tendency to reduce the surface tension proportionally to the respective concentration at the free surface. Thus when surfactant concentration varies across a free surface, surface tension gradients occur and this results in shear stresses, thus altering the boundary condition at the free surface. A low Reynolds number wake behind a surface-piercing cylinder was chosen as the field of study, using digital particle image velocimetry (DPIV) to map the velocity and vorticity held for three orthogonal cross-sections of the flow. Reynolds numbers ranged from 350 to 460 and the Froude number was kept below 1.0. In addition, a new technique was used to simultaneously map the free surface deformation. Shadowgraph imaging of the free surface was also used to gain a better understanding of the how. It was found that, depending on the surface condition, the connection of the shedding vortex filaments in the wake of the cylinder was greatly altered with the propensity for surface tension gradients to redirect the vorticity near the free surface to that of the surface-parallel component. This result has an impact on the understanding of turbulent flows in the vicinity of a free surface with varying surface conditions.
Multiple absorption of laser photons by atoms

Applying a space translation operation, the Schrodinger equation for an atom in an electromagnetic field is solved with sufficient accuracy to obtain probabilities for multiple absorption of photons from a monochromatic laser beam of arbitrary intensity or frequency. It is shown that the derived expression for the N-photon T-matrix contains the usual single photon matrix elements given by the perturbation theory and that the perturbative result is obtained in the limit of low intensity. Other explicit examples are considered. The conditions of applicability of the method are specified.
THERMAL BUOYANCY ON VENUS: UNDERTHRUSTING VS SUBDUCTION

The thermal and buoyancy consequences of the subduction endmember are modeled in an attempt to evaluate the conditions distinguishing underthrusting and subduction. Thermal changes in slabs subducting into the Venusian mantle with a range of initial geotherms are used to predict density changes and, thus, slab buoyancy. Based on a model for subduction-induced mantle flow, it is then argued that the angle of the slab dip helps differentiate between underthrusting and subduction. Mantle flow applies torques to the slab which, in combination with torques due to slab buoyancy, act to change the angle of slab dip.
Multimodal interfaces for multimedia information agents

When humans communicate they take advantage of a rich spectrum of cues. Some are verbal and acoustic. Some are non-verbal and non-acoustic. Signal processing technology has devoted much attention to the recognition of speech, as a single human communication signal. Most other complementary communication cues, however, remain unexplored and unused in human-computer interaction. In this paper we show that the addition of non-acoustic or non-verbal cues can significantly enhance robustness, flexibility, naturalness and performance of human-computer interaction. We demonstrate computer agents that use speech, gesture, handwriting, pointing, spelling jointly for more robust, natural and flexible human-computer interaction in the various tasks of an information worker: information creation, access, manipulation or dissemination.
Al2TiO5-ZrTiO4-ZrO2 Composites: A New Family of Low-Thermal-Expansion Ceramics

On decrit la caracterisation et les proprietes de composites ceramiques contenant les phases Al 2 TiO 5 , ZrTiO 4 et ZrO 2 . Pour les domaines de composition etudies, on obtient de tres faibles coefficients de dilatation thermique et une excellente stabilite a haute temperature.