cssi/SciSciGPT-SciSciNet huggingface dataset:
SELF-AVERAGING IN TIME REVERSAL FOR THE PARABOLIC WAVE EQUATION

We analyze the self-averaging properties of time-reversed solutions of the paraxial wave equation with random coefficients, which we take to be Markovian in the direction of propagation. This allows us to construct an approximate martingale for the phase space Wigner transform of two wave fields. Using a prioriL2-bounds available in the time-reversal setting, we prove that the Wigner transform in the high frequency limit converges in probability to its deterministic limit, which is the solution of a transport equation.
Dimerization of ethylene to butene-1 catalyzed by Ti(OR')4-AlR3

The catalytic dimerization of ethylene stands as the most selective and economical route to polymerization grade butene-1. This approach is currently exemplified by the IFP-SABIC process for the production of butene-1 wherein ethylene is dimerized over the modified Ziegler-Natta homogeneous catalysts Ti(OR')4-A1R3 (R' = C1-C8 alkyl or aryl, R = C1-C6 alkyl). The mass of the published patents and the technical literature dealing with the ethylene dimerization over various transition metal based complexes is overwhelming. Therefore, the literature taken into account in this review was selected in order to give more weight to fundamental studies and less to patent claims. This paper is dedicated to discussing the chemical perspectives of the dimerization reaction over the titanium-based catalytic system with its main objective being to get a more decisive picture on the performance of these catalysts. This review paper identifies the components of this homogeneous system and discusses, in fair detail, the factors controlling its selectivity to butene-1. Other different themes covered include: structure of the active species, kinetics, mechanistic considerations and the principal reaction parameters. Additionally, this survey is supplemented by a summarized account for the corresponding supported titanate catalysts and their usage as a dimerization component in the dual functional catalytic systems.
The Antonelli Versus Hicks Elasticity of Complementarity and Inverse Input Demand Systems

A true measure of input substitution associated with exogenous changes in input quantities requires that the output level be held constant. To this effect, this study presents the Antonelli elasticity of complementarity characterised by the distance function. The more common Hicks elasticity of complementarity assumes that marginal cost is constant and hence does not capture pure substitution effects. The two elasticities of complementarity are related to inverse demand systems and are shown to be equivalent under constant returns to scale. A framework for estimating the Antonelli elasticity from the uncompensated demand system is presented. Estimation results reveal substantial bias of input substitutability with the use of Hicks' measure.
Continuity of Eigenfunctions of Uniquely Ergodic Dynamical Systems and Intensity of Bragg Peaks

We study uniquely ergodic dynamical systems over locally compact, sigma-compact Abelian groups. We characterize uniform convergence in Wiener/Wintner type ergodic theorems in terms of continuity of the limit. Our results generalize and unify earlier results of Robinson and Assani respectively.
Violation of the principle of complementarity, and its implications

Bohr's principle of complementarity predicts that in a welcher weg ("which-way") experiment, obtaining fully visible interference pattern should lead to the destruction of the path knowledge. Here I report a failure for this prediction in an optical interferometry experiment. Coherent laser light is passed through a dual pinhole and allowed to go through a converging lens, which forms well-resolved images of the respective pinholes, providing complete path knowledge. A series of thin wires are then placed at previously measured positions corresponding to the dark fringes of the interference pattern upstream of the lens. No reduction in the resolution and total radiant flux of either image is found in direct disagreement with the predictions of the principle of complementarity. In this paper, a critique of the current measurement theory is offered, and a novel nonperturbative technique for ensemble properties is introduced. Also, another version of this experiment without an imaging lens is suggested, and some of the implications of the violation of complementarity for another suggested experiment to investigate the nature of the photon and its "empty wave" is briefly discussed.
Multidomain decomposition approach to large-scale electronic structure calculations

An electronic structure calculation is presented which is based on a multidomain decomposition of the coordinate space. Using the Green's operator the electron density is calculated without calculating the Kohn-Sham single-particle states, thus avoiding matrix diagonalizations. The method is simple to implement and easy to parallelize. The approach is tested on nanosystems containing over $10\text{ }000$ atoms using a single processor.
Bundle-level type methods uniformly optimal for smooth and nonsmooth convex optimization

The main goal of this paper is to develop uniformly optimal first-order methods for convex programming (CP). By uniform optimality we mean that the first-order methods themselves do not require the input of any problem parameters, but can still achieve the best possible iteration complexity bounds. By incorporating a multi-step acceleration scheme into the well-known bundle-level method, we develop an accelerated bundle-level method, and show that it can achieve the optimal complexity for solving a general class of black-box CP problems without requiring the input of any smoothness information, such as, whether the problem is smooth, nonsmooth or weakly smooth, as well as the specific values of Lipschitz constant and smoothness level. We then develop a more practical, restricted memory version of this method, namely the accelerated prox-level (APL) method. We investigate the generalization of the APL method for solving certain composite CP problems and an important class of saddle-point problems recently studied by Nesterov (Math Program 103:127---152, 2005). We present promising numerical results for these new bundle-level methods applied to solve certain classes of semidefinite programming and stochastic programming problems.
Blowup subalgebras of the Sklyanin algebra

Abstract We describe some interesting graded rings which are generated by degree-3 elements inside the Sklyanin algebra S, and prove that they have many good properties. Geometrically, these rings R correspond to blowups of the Sklyanin P 2 at 7 or fewer points. We show that the rings R are exactly those degree-3-generated subrings of S which are maximal orders in the quotient ring of the 3-Veronese of S.
Combinatorial excess intersection

We provide formulas and develop algorithms for computing the excess numbers of an ideal. The solution for monomial ideals is given by the mixed volumes of polytopes. These results enable us to design numerical algebraic geometry homotopies to compute excess numbers of any ideal.
The generalized road coloring problem and periodic digraphs

A proof of the Generalized Road Coloring Problem, independent of the recent work by Beal and Perrin, is presented, using both semigroup methods and Trakhtman’s algorithm. Algebraic properties of periodic, strongly connected digraphs are studied in the semigroup context. An algebraic condition which characterizes periodic, strongly connected digraphs is determined in the context of periodic Markov chains.
Total synthesis of the cytotoxic Annonaceous acetogenin (30S)-bullanin

Abstract The total synthesis of (+)-(30S)-bullanin, a highly cytotoxic annonaceous acetogenin, was effected by a convergent approach in which the key core bis -2,2′-tetrahydrofuran stereocenters were introduced through a combination of Sharpless asymmetric dihydroxylation and S E 2′ additions of oxygenated nonracemic allylic stannane and indium reagents to γ-oxygenated aldehydes.
Alternate compactifications of the moduli space of genus one maps

We extend the definition of an m-stable curve introduced by Smyth to the setting of maps to a projective variety X, generalizing the definition of a Kontsevich stable map in genus one. We prove that the moduli problem of n-pointed m-stable genus one maps of class β is representable by a proper Deligne–Mumford stack \({\overline{\mathcal {M}}_{1,n}^{m}(X,\beta)}\) over Spec \({\mathbb {Z}[1/6]}\) . For \({X=\mathbb {P}^{r},}\) we show that \({\overline{\mathcal {M}}_{1,n}^{m}(\mathbb {P}^{r},d)}\) is irreducible for m sufficiently large. We also show that \({\overline{\mathcal {M}}_{1,n}^{m}(\mathbb {P}^r,d)}\) is smooth if d + n ≤ m ≤ 5.
A density functional study of atomic hydrogen and oxygen chemisorption on the relaxed (0001) surface of double hexagonal close packed americium

Ab initio total energy calculations within the framework of density functional theory have been performed for atomic hydrogen and oxygen chemisorption on the (0001) surface of double hexagonal packed americium using a full-potential all-electron linearized augmented plane wave plus local orbitals method. Chemisorption energies were optimized with respect to the distance of the adatom from the relaxed surface for three adsorption sites, namely top, bridge, and hollow hcp sites, the adlayer structure corresponding to coverage of a 0.25 monolayer in all cases. Chemisorption energies were computed at the scalar-relativistic level (no spin-orbit coupling NSOC) and at the fully relativistic level (with spin-orbit coupling SOC). The two-fold bridge adsorption site was found to be the most stable site for O at both the NSOC and SOC theoretical levels with chemisorption energies of 8.204 eV and 8.368 eV respectively, while the three-fold hollow hcp adsorption site was found to be the most stable site for H with chemisorption energies of 3.136 eV at the NSOC level and 3.217 eV at the SOC level. The respective distances of the H and O adatoms from the surface were found to be 1.196 Aand 1.164 A. Overall our calculations indicate that chemisorption energies in cases with SOC are slightly more stable than the cases with NSOC in the 0.049–0.238 eV range. The work functions and net magnetic moments respectively increased and decreased in all cases compared with the corresponding quantities of bare dhcp Am (0001) surface. The partial charges inside the muffin-tins, difference charge density distributions, and the local density of states have been used to analyze the Am-adatom bond interactions in detail. The implications of chemisorption on Am 5f electron localization-delocalization are also discussed.
Impedance characterization of microarray recording electrodes in vitro

The mechanisms underlying performance degradation of chronically implanted silicon microelectrode arrays in the central nervous system (CNS) remain unclear. Humoral and cellular components of the brain foreign body response were evaluated to determine whether their presence on the electrode surface results in increased electrical impedance. Iridium oxide microelectrode recording arrays were electrically characterized in saline, culture media with 10% fetal bovine serum, and coated with various CNS cell types isolated from rat brain. Electrochemical impedance spectroscopy and cyclic voltammetry were performed using a three-electrode system. Potential cycling caused an immediate decrease in electrical impedance, which increased with time toward precycling values, with the effect of cycling remaining significant for several days. The addition of serum caused a significant increase in impedance of up to 28% relative to the saline control. Microelectrodes coated with various cell types known to participate in the foreign body response caused a 20%-80% increase in impedance immediately after contact that remained constant or gradually increased for several weeks. Our findings suggest that the attachment of molecular and cellular species following microelectrode implantation into brain tissue likely contribute to increases in impedance, but do not appear sufficient to hinder recording performance.
New Insights into Nucleosome Unwrapping

Recently, a new approach for direct mapping of nucleosome centers at base-pair resolution was developed [1] and some intriguing results appeared. About 40% of the inter-dyad distances are smaller than 147 base-pairs, which indicates massive nucleosome unwrapping, genome-wide, in vivo. Paired-end reads give, for the first time, precise information about neighboring nucleosomes which come from the same cell. The histogram of the inter-dyad distances presents small oscillations with the period of about 10 base-pairs. These oscillations indicate a step-wise unwrapping of the nucleosomal DNA from the histone.One-dimensional lattice models can reproduce characteristic patterns observed in the distribution of the nucleosomes along the chromosomes [2, 3]. We present a statistical mechanics model [4] for the nucleosome unwrapping, which is able to take into account sequence-dependent binding energies, sequence-independent potential barriers and wells, effective two-body interactions between the nucleosomes, competition between different species (e.g. nucleosomes and transcription factors, RNA polymerase, etc.), cooperative-binding, and other important factors which dictate the nucleosome distribution along the DNA. We solve both the direct and the inverse problems.Using our model, we are able to reproduce the distribution of the inter-dyad distances, which clearly cannot be obtained using the assumption that all histones cover the same length of DNA (i.e. there is no unwrapping).An extended abstract can be found here: http://www.physics.rutgers.edu/∼rchereji/unwrap.pdfReferences:[1] K. Brogaard et al., Nature 486, 496-501 (2012).[2] R. V. Chereji et al., Phys. Rev. E 83, 050903 (2011).[3] R. V. Chereji and A. V. Morozov, J. Stat. Phys. 144, 379-404 (2011).[4] R. V. Chereji and A. V. Morozov, in preparation.
Identity and Environmentalism: The Influence of Community Characteristics

This paper examines the influence of community characteristics on self-proclaimed environmentalism. We find that the composition of a community affects the likelihood that a person claims to be a strong environmentalist even after controlling for individual political leaning, socio-economic characteristics, and pro-environment behaviors. Individuals are more likely to claim to be strong environmentalists if they live in areas where a larger share of the population has post-graduate degrees, if they live in heavily Democratic areas, or if they live in heavily Republican areas. These community effects occur only when individuals are predisposed to take on an environmental identity.
Efficient palladium-mediated synthesis of a spirocyclic model for fredericamycin A.

Abstract A palladium-promoted intramolecular arylation of a β-diketone generates a spirocyclic system as a model for Fredericamycin A.
Operating systems principles and undergraduate computer science curricula

In the years since 1969, the study of computer systems has assumed a role nearly equal in importance to "theory of computation" and "programming" in computer science curricula. In contrast, computer systems was regarded as recently as 1965 as being inferior in importance to these two more traditional areas of study. This is a significant change in attitude. The harbingers of the change appear in ACM's Curriculum 68, and the speed of its development is demonstrated in the report of Task Force VIII of the COSINE (Computer Science in Electrical Engineering) committee of the Commission on Education of the National Academy of Engineering, entitled "An Undergraduate Course on Operating Systems Principles."
Pearson near-total laryngectomy: A reproducible speaking shunt

Background. Since 1980, Pearson and his associates at the Mayo Clinic have accrued an increasing number of patients whom they have treated with what is now designated as a “near-total” laryngectomy rather than a total laryngectomy. Despite the positive reports of the value of this procedure in providing speech by an internal shunt, the use of this total laryngectomy alternative has not gained wide acceptance. We report our experience with treating 11 patients during a 3-year period using the near-total laryngectomy. Methods. Between September 1989 and September 1992, 11 patients with the following anatomic lesions were offered and accepted the option of the near-total laryngectomy: (1) T3 or early T4 glottic squamous cell carcinoma that did not involve the interarytenoid space or the vocal process of the opposite arytenoid; (2) T3 supraglottic squamous cell carcinoma with a fixed vocal cord in which a supraglottic laryngectomy could not be performed; (3) T2, T3 pyriform sinus squamous cell carcinomas; (4) radiotherapy failure early glottic lesions in which a vertical hemilaryngectomy for salvage was not able to be performed and met the requirements in (1); and (5) large hypopharyngeal lesions in which the larynx would be sacrificed to prevent aspiration but was not involved with tumor. Results. Nine of 11 patients (82%) attained successful speech in an average of 5.3 months. Two of the 11 patients required a completion laryngectomy, both due to wound complications. All but two of the patients received postoperative radiotherapy. Of the nine successful speakers, five have had an occasional droplet of fluid through the shunt; three have been on a permanent basis and two transient. Eighty-nine percent of the speaking patients (8 of 9) are alive without disease, a mean of 25.5 months after therapy completion. Conclusions. The near-total laryngectomy can be performed outside the Mayo Clinic with creditable results, with 82% of the patients attaining successful speech, an average of 5.3 months postoperatively. Eighty-nine percent of the speakers have had a mean disease-free survival of 25.5 months. Analysis of larger series from multiple institutions in conjunction with voice analyses of these patients compared to those with tracheoesophageal punctures is needed to confirm our initial enthusiasm for this procedure. © 1994 John Wiley & Sons, Inc.
Tree-Manipulating Systems and Church-Rosser Theorems

Subtree replacement systems form a broad class of tree-manipulating systems. Systems with the “Church-Rosser property” are appropriate for evaluation or translation processes: the end result of a complete sequence of applications of the rules does not depend on the order in which the rules were applied. Theoretical and practical advantages of such flexibility are sketched. Values or meanings for trees can be defined by simple mathematical systems and then computed by the cheapest available algorithm, however intricate that algorithm may be.We derive sufficient conditions for the Church-Rosser property and discuss their applications to recursive definitions, to the lambda calculus, and to parallel programming. Only the first application is treated in detail. We extend McCarthy's recursive calculus by allowing a choice between call-by-value and call-by-name. We show that recursively defined functions are single-valued despite the nondeterminism of the evaluation algorithm. We also show that these functions solve their defining equations in a “canonical” manner.
Deformation Theory of Modules

ABSTRACT Algebraic deformations of modules over a ring are considered. The resulting theory closely resembles Gerstenhaber's deformation theory of associative algebras.
A Summary of NASA and USAF Hypergolic Propellant Related Spills and Fires

Several unintentional hypergolic fluid related spills, fires, and explosions from the Apollo Program, the Space Shuttle Program, the Titan Program, and a few others have occurred over the past several decades. Spill sites include the following government facilities: Kennedy Space Center (KSC), Johnson Space Center (JSC), White Sands Test Facility (WSTF), Vandenberg Air Force Base (VAFB), Cape Canaveral Air Force Station (CCAFS), Edwards Air Force Base (EAFB), Little Rock AFB, and McConnell AFB. Until now, the only method of capturing the lessons learned from these incidents has been "word of mouth" or by studying each individual incident report. The root causes and consequences of the incidents vary drastically; however, certain "themes" can be deduced and utilized for future hypergolic propellant handling. Some of those common "themes" are summarized below: (1) Improper configuration control and internal or external human performance shaping factors can lead to being falsely comfortable with a system (2) Communication breakdown can escalate an incident to a level where injuries occur and/or hardware is damaged (3) Improper propulsion system and ground support system designs can destine a system for failure (4) Improper training of technicians, engineers, and safety personnel can put lives in danger (5) Improper PPE, spill protection, and staging of fire extinguishing equipment can result in unnecessary injuries or hardware damage if an incident occurs (6) Improper procedural oversight, development, and adherence to the procedure can be detrimental and quickly lead to an undesirable incident (7) Improper materials cleanliness or compatibility and chemical reactivity can result in fires or explosions (8) Improper established "back-out" and/or emergency safing procedures can escalate an event The items listed above are only a short list of the issues that should be recognized prior to handling hypergolic fluids or processing vehicles containing hypergolic propellants. The summary of incidents in this report is intended to cover many more issues than those listed above.
Gore/seam architectures for gossamer structures

Gossamer spacecraft are ultra-low-mass (areal densities <1 kg/m 2 ) structures with applications in communications, imaging, and propulsion. Often large, for example, diameters greater than 10 m, aperture architectures canbe either filled (monolithic) or sparse (segmented). Although filled apertures provide the greatest performance, manufacture of large monolithic, that is, seamless, apertures is extremely challenging, Gore/seam architectures provide a compromise for fabrication of gossamer spacecraft. Segments (gores) are manufactured and then assembled into a continuous aperture by seaming together the gores. A similar process was chosen for the Inflatable Antenna Experiment and has been used for decades in the fabrication of large high-altitude scientific balloons. The architecture options for design and fabrication of gossamer spacecraft are reviewed, with particular emphasis on precision applications in communications and imaging. The near-term inevitability of seaming as a fabrication method is emphasized, and the point of view is taken of using seams to advantage. The possibility of "active seams" to mitigate some of the aforementioned issues is discussed and extended to go further to find other uses for the active seams. Lessons learned from NASA's high-altitude balloon program are reviewed in improving structural integrity through use of novel gore/seam design.
Submillimeter and millimeter masers

Despite theoretical predictions of the existence of many submillimeter masers, and some pioneering observational discoveries over the past few decades, these lines have remained relatively unstudied due to (i) challenges associated with observing at shorter wavelength; and, (ii) the lack of possibility of high ( 2 O millimeter masers, hydrogen recombination masers, submillimeter masers in star-forming regions, and in the envelopes of evolved stars - and discuss prospects for the future.
Transverse acoustoelectric voltage inversion and its application to semiconductor surface study: CdS

Abstract The transverse acoustoelectric voltage inversion has been observed in CdS. It is found to be due to the inversion of the semiconductor surface. The inversion layer results from a high magnitude of the dc transverse acoustoelectric voltage developed on the semiconductor surface. The acoustoelectric voltage inversion is strongly dependent on the wavelength and intensity of light illuminating the semiconductor surface, and the power input of the SAW. The sub bandgap spectral response of the transverse acoustoelectric voltage determines the positions of the surface states in the energy gap. The above bandgap spectrum determines the photon energy in which transition from bulk to surface absorption takes place and the photon energy for complete surface absorption.
Palladium-catalyzed insertion reactions of trimethylsilyldiazomethane

Abstract Palladium(II) salts catalyze the Kirmse reaction of allylsulfides with trimethylsilyldiazomethane (TMSD) to give homoallylsulfides. Similarly, TMSD can intercept ArPdX intermediates generated during Stille couplings to give benzhydryl derivatives. The yields of this process are limited by overinsertion and β-elimination. Insertion and elimination can be harnessed to generate styrenes from benzylic halides in the presence of palladium (0) catalysts.
Lifting Lie algebras over the residue field of a discrete valuation ring

Let R be a discrete valuation ring with maximal ideal πR and residue field k. We study obstructions to lifting a Lie algebra L over R/πkR to one over R/πk+1R. If L is the Lie algebra over k obtained from reducing L then we show there exists a well-defined class in H3(L,ad) which vanishes if and only if L lifts. Furthermore, if L lifts, the lifts are shown to be in one to one correspondence with H2(L,ad).
Insurance and catastrophes

Catastrophes provide a principal justification for insurance. Traditional conceptions of catastrophes miss three critical elements. (1) Many catastrophes—the liability revolution in the United States, for example—are not bolts from the blue. Rather, they develop over many years and result from human activity. (2) Conventional, experiencedbased models for assessing losses often smudge the distinction, so critical for catastrophes, between probability and magnitude of loss. (3) Normal insurance contracts, with heavy copayments for small losses but little charge at the margin for large ones, perform poorly when the insured can tradeoff probability and size of loss—a phenomenon we label distribution distortion. The structures of optimal insurance contracts are assessed.
Hypersensitive radical probes and the mechanisms of cytochrome P450-catalyzed hydroxylation reactions.

The title probes are precursors to kinetically calibrated, aryl-substituted cyclopropylcarbinyl radicals that rearrange with picosecond lifetimes. Applications in studies of cytochrome P450-catalyzed hydroxylation reactions are reviewed. Initially confusing results regarding lifetimes of radicals in the hydroxylation reactions were resolved when second-generation probes that distinguish between radicals and cations were employed. The results indicate that two electrophilic oxidizing species are involved in P450-catalyzed hydroxylations, an iron-oxo species that inserts oxygen and a hydroperoxo-iron species that inserts OH+. The cationic rearrangement products are ascribed to reactions of the protonated alcohol products formed from the latter.
Large deviations and slowdown asymptotics for one-dimensional excited random walks

We study the large deviations of excited random walks on $\mathbb{Z}$. We prove a large deviation principle for both the hitting times and the position of the random walk and give a qualitative description of the respective rate functions. When the excited random walk is transient with positive speed $v_0$, then the large deviation rate function for the position of the excited random walk is zero on the interval $[0,v_0]$ and so probabilities such as $P(X_n 2$ is the expected total drift per site of the cookie environment.
Jets and Disk Winds from Pulsar Magnetospheres

We discuss axisymmetric force-free pulsar magnetospheres with magnetically collimated jets and a disk wind obtained by numerical solution of the pulsar equation. This solution represents an alternative to the quasi-spherical wind solutions in which a major part of the current flow is in a current sheet that is unstable to magnetic field annihilation.
Separate processes in the relation of elation and depression to helping: Social versus personal concerns

Abstract The Separate Process analysis suggests that individuals in an elated mood are most affected by social concerns associated with a helping request, whereas individuals in a depressed mood are most influenced by the personal hedonic considerations involved with the request. In Experiment 1, subjects received either an elating, neutral, or depressing mood induction, after which they were asked to help either on a task of high interest valence, described as fun, or low interest valence, described as dull. After the request, a confederate volunteered to help and provided either high social inducement to help for the subject by encouraging volunteering, or low social inducement to help by volunteering for the self alone. Suggesting increased social interest, elated subjects were more likely than neutral subjects to help with both high and low interest tasks. Elated subjects also were significantly more likely to volunteer under conditions of high social inducement, but that variable had little impact on negative and neutral mood subjects. The personal concern associated with negative mood was evident in the finding that depression significantly increased helping only when the task had a positive interest valence. Experiment 2 replicated Experiment 1, but operationalized both social and personal concerns in terms of the content of the helping opportunity. Positive mood subjects were significantly more likely than neutral and negative mood subjects to volunteer for a Social task, involving a group discussion. Negative mood subjects, by contrast, were significantly more likely to volunteer for a task having positive hedonic consequences, involving the rating of jokes, than for the Social task.
Constraining spiral structure parameters through Galactic pencil-beam and large-scale radial velocity surveys

We investigate the effect of spiral structure on the Galactic disc as viewed by pencil beams centred on the Sun, relevant to upcoming surveys such as ARGOS, SEGUE and GAIA. Using a steady-state spiral structure model, we create synthetic Galactic maps which we call pencil-beam maps (PBMs) of the following observables: line-of-sight velocities, the corresponding velocity dispersion and the stellar number density that are functions of distance from the observer. We show that PBMs are a powerful tool for analysing spiral patterns but the uncertainty of the Milky Way structure prevents their simple interpretation. For the case of steady-state spiral structure, we show that such maps can be used to infer spiral structure parameters, such as pattern speed, solar phase angle and number of arms. The mean line-of-sight velocity and velocity dispersion are affected by up to ∼35 km s -1 , which is well within the detectable limit for forthcoming radial velocity surveys. One can measure the pattern speed by searching for imprints of resonances. In the case of a two-armed spiral structure it can be inferred from the radius of a high velocity dispersion ring situated at the 2:1 inner Lindblad resonance (ILR). This information, however, must be combined with information related to the velocities and stellar number density in order to distinguish from a four-armed structure. If the pattern speed is such that the 2:1 ILR is hidden inside the Galactic bulge, the 2:1 outer Lindblad resonance will be present in the outer Galaxy and thus can equivalently be used to estimate the pattern speed. Once the pattern speed is known, the solar angle can be estimated from the line-of-sight velocities and the number density PBMs. The models presented here are preliminary as transient spiral structure models should also be considered. Forthcoming radial velocity surveys are likely to provide powerful constraints of the structure of the Milky Way disc.
Breast cancer in the third millennium

Abstract: Management of breast cancer is entering a phase of dramatic changes based on screening, more sophisticated therapy, and the development of “high technology” solutions through research. Appreciation of basic principles of biological behavior and therapy need current emphasis, however. By 2015 the American Cancer Society goals of 50% reduction in mortality and 25% reduction in incidence should be met and probably exceeded in breast cancer.
The support problem for abelian varieties

Abstract Let A be an abelian variety over a number field K. If P and Q are K-rational points of A such that the order of the ( mod p ) reduction of Q divides the order of the ( mod p ) reduction of P for almost all prime ideals p , then there exists a K-endomorphism φ of A and a positive integer k such that φ(P)=kQ.
Multifetal reduction increases the risk of preterm delivery and fetal growth restriction in twins: a case-control study.

Objective: To compare pregnancy outcome in twin gestations resulting from multifetal reduction to "primary" twin pregnancies derived from either spontaneous conception or infertility therapy. Design: Case-control study. Setting: University-affiliated tertiary center. Patient(s): Multifetal pregnancies (quadruplets or more) reduced to twins (group A) compared with twin gestations conceived either spontaneously (group B) or through infertility therapy (group C). Intervention(s): Multifetal reduction for group A; perinatal care for groups A, B, and C. Main Outcome Measure(s): Comparison of perinatal complications between groups including antepartum bleeding, premature membrane rupture, and preterm labor. Neonatal outcomes compared including gestational age at delivery, birth weight, incidence of fetal growth restriction, and twin discordancy. Result(s): A higher incidence of idiopathic preterm labor was noted in group A cases (14/18) compared with either of the control groups (B: 26/54, or C: 24/54). As a consequence, group A had the lowest gestational age at delivery (32.6 ± 3.9 weeks) compared with groups B (33.6 ± 4.4 weeks) and C (36.0 ± 3.4 weeks). Corresponding birth weights of both first- and second-born twins were significantly lower in group A compared with group C, whereas the birth weight comparison between groups A and B showed a nonsignificant difference. The proportion of pregnancies in which one or both twins weighed less than the 10th percentile was greatest in group A pregnancies (A: 5/18 versus C: 5/54). Discordant birth weight among twin pairs was proportionately greater for group A cases at both the 20% and 30% discordance levels. Conclusion(s): Twin gestations resulting from multifetal reduction are at increased risk for preterm birth, fetal growth restriction, and discordancy when compared with fertility therapy-derived, nonreduced twins.
The Azomethine Ylide Route to Amine C–H Functionalization: Redox-Versions of Classic Reactions and a Pathway to New Transformations

ConspectusRedox-neutral methods for the functionalization of amine α-C–H bonds are inherently efficient because they avoid external oxidants and reductants and often do not generate unwanted byproducts. However, most of the current methods for amine α-C–H bond functionalization are oxidative in nature. While the most efficient variants utilize atmospheric oxygen as the terminal oxidant, many such transformations require the use of expensive or toxic oxidants, often coupled with the need for transition metal catalysts.Redox-neutral amine α-functionalizations that involve intramolecular hydride transfer steps provide viable alternatives to certain oxidative reactions. These processes have been known for some time and are particularly well suited for tertiary amine substrates. A mechanistically distinct strategy for secondary amines has emerged only recently, despite sharing common features with a range of classic organic transformations. Among those are such widely used reactions as the Strecker, Mannich, P...
Next generation farms at Fermilab

Abstract The current generation of UNIX farms at Fermilab are rapidly approaching the end of their useful life. The workstations were purchased during the years 1991–1992 and represented the most cost-effective computing available at that time. Acquisition of new workstations has been made to upgrade the UNIX farms for the purpose of providing large amounts of computing for reconstruction of data collected at the 1996–1997 fixed-target run, as well as to provide simulation computing for CMS, the Auger project, accelerator calculations and other projects that require massive amounts of CPU.
Dynamics of the Narrow-Line Region in the Seyfert 2 Galaxy NGC 1068*

We present dynamical models based on a study of high-resolution long-slit spectra of the narrow-line region (NLR) in NGC 1068 obtained with the Space Telescope Imaging Spectrograph (STIS) aboard the Hubble Space Telescope (HST). The dynamical models consider the radiative force due to the active galactic nucleus (AGN), gravitational forces from the supermassive black hole (SMBH), nuclear stellar cluster, and galactic bulge, and a drag force due to the NLR clouds interacting with a hot ambient medium. The derived velocity profile of the NLR gas is compared to that obtained from our previous kinematic models of the NLR, using a simple biconical geometry for the outflowing NLR clouds. The results show that the acceleration profile due to radiative line driving is too steep to fit the data and that gravitational forces alone cannot slow the clouds down, but with drag forces included, the clouds can slow down to the systemic velocity over the range 100-400 pc, as observed. However, we are not able to match the gradual acceleration of the NLR clouds from ~0 to 100 pc, indicating the need for additional dynamical studies.
The Ionization Fraction in Dense Molecular Gas. II. Massive Cores

We present an observational and theoretical study of the ionization fraction in several massive cores located in regions that are currently forming stellar clusters. Maps of the emission from the J=1→0 transitions of C18O, DCO+, N2H+, and H13CO+, as well as the J=2→1 and 3→2 transitions of CS, were obtained for each core. Core densities are determined via a large velocity gradient analysis with values typically of ~105 cm-3. With the use of observations to constrain variables in the chemical calculations, we derive electron fractions for our overall sample of five cores directly associated with star formation and two apparently starless cores. The electron abundances are found to lie within a small range, -6.9 < log10xe < -7.3, and are consistent with previous work. We find no difference in the amount of ionization fraction between cores with and without associated star formation activity, nor is any difference found in electron abundances between the edge and center of the emission region. Thus our models are in agreement with the standard picture of cosmic rays as the primary source of ionization for molecular ions. With the addition of previously determined electron abundances for low-mass cores, and even more massive cores associated with O and B clusters, we systematically examine the ionization fraction as a function of star formation activity. This analysis demonstrates that the most massive sources stand out as having the lowest electron abundances (xe < 10-8).
Biplanar bicycle as a base vehicle for autonomous applications

Virginia Tech has developed a novel two-wheeled vehicle termed the biplanar bicycle. This vehicle differs from the traditional bicycle in that both wheels rotate about a common axis, thus orienting the wheels side by side instead of front to back. Drive motors generate the propulsive torque by acting against a central reaction mass (the vehicle body) suspended from the axle. This vehicle offers several advantages over traditional wheeled vehicles. Among these are inherent stability, self-righting ability, and excellent mobility in two degrees of freedom (the ground plane). The physical architecture makes the vehicle exceedingly nimble through a wide range of speeds. Further, the entire mass of this vehicle is distributed between the two drive wheels, thus maximizing the available frictional driving force. The vehicle dynamics resulting from the system geometry affords very low slip and good acceleration. These advantages, coupled with a simple mechanical design, make the biplanar bicycle a good candidate for use as a platform vehicle in autonomous applications. Some potential applications include rail line inspection, landmine/UXO detection, and planetary exploration. This paper presents results from prototype testing of the biplanar bicycle. Various issues concerning sensors and control strategies unique to this vehicle are examined. While the conceptual basis of this vehicle may be counterintuitive, the design is fundamentally sound and viable for autonomous vehicle applications.
Decision regions of Fourier-plane nonlinear filtering for image recognition

In image recognition applications, complex decision regions in the image space are needed. Linear filtering forms the decision regions by hyperplanes in the image space. We determine the decision region formed by Fourier-plane nonlinear filtering. In the case in which power law nonlinearity is applied in the Fourier plane, the decision region turns out to be approximately an n-dimensional parabola that opens toward the direction of the reference vector. That is, the intersection of the decision region with any plane (two-dimensional vector space) not containing any vector parallel to the reference vector is a bounded convex region enclosed by a closed curve. The size of the convex region depends on the filter nonlinearity, which determines the distortion robustness and discrimination capability of the filter. It can be adjusted by choosing different Fourier-plane nonlinearities and/or different threshold values at the output plane. These types of regions are desirable and well suited in image recognition. Analytical and numerical solutions are provided.
Simulation Studies of the Self-Assembly of Cone-Shaped Particles

We investigate the self-assembly of anisotropic cone-shaped particles decorated by ringlike attractive "patches". In a recent paper, we demonstrated that the self-assembled clusters, which arise due to the conical particle's anisotropic shape combined with directional attractive interactions, are precise for certain cluster sizes, resulting in a precise packing sequence of clusters of increasing sizes with decreasing cone angles (Chen et al. Proc. Natl. Acad. Sci. U.S.A. 2007, 104, 717-722). Here we explore the dependence of cluster packing on the cone angle and cooling rate and discuss the "stability" and "metastability" of the resulting structures as well as polymorphism of non-"magic-number" clusters. We investigate large clusters of cones and discuss the implication of our simulation results in the context of the Israelachvili packing rule for surfactants and a recent geometrical packing analysis on hard cones in the limit of large numbers of cones.
Nonthermal Emission from Accreting and Merging Clusters of Galaxies

We compare the nonthermal emission from clusters of galaxies undergoing minor mergers (accreting clusters) and major mergers (merging clusters). We define major mergers as mergers that change the inner dark matter structure of clusters; minor mergers are all others. For accreting clusters, the radial distribution of the nonthermal emission in the clusters is also calculated. The relativistic electrons, which are the origin of the nonthermal radiation through inverse Compton (IC) and synchrotron emission, are assumed to be accelerated at shocks produced by accretion or mergers. We estimate the typical accretion rate and merger probability according to a hierarchical clustering model. We predict that in the inner region of accreting clusters the nonthermal emission has a flat spatial distribution at all frequencies. For synchrotron and hard X-ray emissions, we predict an increase in the emissions at the cluster edge due to accretion. We show that the total luminosities of IC emission from accreting and merging clusters are similar. On the other hand, the luminosity of synchrotron radio emission of the former is much smaller than that of the latter. We show that about 10% of clusters at z ~ 0 should have hard X-ray and radio nonthermal emissions due to their last major merger that are comparable to or dominate those due to ongoing accretion. Moreover, 20%-40% of clusters should have significant EUV emission due to their last merger. We also investigate the case where the criterion of mergers is relaxed. If we extend the definition of a merger to an increase in the mass of the larger subcluster by at least 10% of its initial mass, about 20%-30% of clusters at z ~ 0 should have hard X-ray and radio nonthermal emissions due to the merger, even in a low-density universe. We compare the results with observations. We find that the observed EUV emission from clusters is not attributed to accretion. If the diffuse radio emission observed in clusters is synchrotron emission from electrons accelerated via accretion or merging, the magnetic fields of clusters are generally as small as ~0.1 μG. One concern is that this is a significantly weaker field than that implied by Faraday rotation measurements.
One‐Pot Oxidative Esterification and Amidation of Aldehydes

During recent years, the direct transformation of aldehydes into esters or amides has developed into a vigorous research area and powerful one-pot oxidative esterification and amidation procedures have been reported. Several concepts that are often complementary in substrate scope, functional group tolerance, and reaction outcome have emerged, thus providing a wide range of alternatives to classical ester and amide synthesis via carboxylic acid intermediates.
Maternal tasks in pregnancy.

The directional goals which women strive towards during pregnancy are fourfold and seem to provide the basic framework of motivation in maternal behaviour. Two of the four tasks are directed toward the outer world during pregnancy on behalf of her child: ensuring safety and acceptance of her unborn child. The other two tasks are directed toward the formation of the maternal role and relationship: developing the capacity to give and binding-in to the as yet unborn child. The progression in pursuit of these tasks is directly related to the progress of pregnancy.
X-ray line emission from the TYCHO supernova remnant

The observation of the X-ray spectrum of the Tycho supernova remnant in the energy range 0.5 to 20 keV is discussed. Four significant line features in the spectrum: The K alpha lines of silicon, sulphur, and iron; and the L lines of iron are examined. Comparisons between the silicon and sulphur equivalent widths and K alpha iron line energies of Tycho and Cas A are discussed. Suggest that the X-ray emitting plasma in Tycho is further from collisional ionization equilibrium than that of Cas A.
A mesoscale fuel reformer to produce syngas in portable power systems

Abstract Current advances in mobile devices bring about power demands that are quickly outpacing available battery technologies. Portable power systems based on fuel cells promise higher power densities, but face challenges with respect to the storage of suitable fuels. Hydrocarbon fuels offer high power densities and can be reformed into a hydrogen-rich syngas, which, once purified, can be used to power hydrogen operated fuel cells. In this paper, we present experimental results for a novel non-catalytic mesoscale fuel reformer concept, which is based on heat recirculation between parallel channels with opposing flow directions. The experimental results substantiate earlier analytical results by the authors predicting stationary combustion zones viable beyond the conventional rich flammability limit, where conditions are favorable for syngas production. Tests of a reactor prototype with four channels, 4 mm high, 91.5 mm long and 33.6 mm wide, showed the feasibility of the non-catalytic fuel reformer concept. Stationary combustion fronts were established for premixed methane/air mixtures at equivalence ratios between 1.8 and 2.5. For constant equivalence ratios, operation was possible for a wide range of firing rates, which is equivalent to a large turn-down ratio. In addition, superadiabatic temperatures substantially increase reaction rates, which result in a high power density of the fuel reformer.