cssi/SciSciGPT-SciSciNet huggingface dataset:
Semiparametric Estimation of a Proportional Hazard Model with Unobserved Heterogeneity

The proportional hazard model with unobserved heterogeneity gives the hazard function of a random variable conditional on covariates and a second random variable representing unobserved heterogeneity. This paper shows how to estimate the baseline hazard function and the distribution of the unobserved heterogeneity nonparametrically. The baseline hazard function and heterogeneity distribution are assumed to satisfy smoothness conditions but are not assumed to belong to known, finite-dimensional, parametric families. Existing estimators assume that the baseline hazard function or heterogeneity distribution belongs to a known parametric family. Thus, the estimators presented here are more general than existing ones.
Odd perfect numbers have at least nine distinct prime factors

An odd perfect number, N, is shown to have at least nine distinct prime factors. If 3 l N then N must have at least twelve distinct prime divisors. The proof ultimately avoids previous computational results for odd perfect numbers.
New results for diffusion in Lorentz lattice gas cellular automata

New calculations to over ten million time steps have revealed a more complex diffusive behavior than previously reported of a point particle on a square and triangular lattice randomly occupied by mirror or rotator scatterers. For the square lattice fully occupied by mirrors where extended closed particle orbits occur, anomalous diffusion was still found. However, for a not fully occupied lattice the superdiffusion, first noticed by Owczarek and Prellberg for a particular concentration, obtains for all concentrations. For the square lattice occupied by rotators and the triangular lattice occupied by mirrors or rotators, an absence of diffusion (trapping) was found for all concentrations, except on critical lines, where anomalous diffusion (extended closed orbits) occurs and hyperscaling holds for all closed orbits withuniversal exponentsd f =7/4 and τ=15/7. Only one point on these critical lines can be related to a corresponding percolation problem. The questions arise therefore whether the other critical points can be mapped onto a new percolation-like problem and of the dynamical significance of hyperscaling.
Copper(II)-Catalyzed Aminooxygenation and Carboamination of N-Aryl-2-allylanilines

The scope of the intramolecular copper(II)-catalyzed carboamination and aminooxygenation reactions of olefins has been extended to include N-aryl-2-allylanilines. These substrates exhibit divergent reactivity under catalytic vs. stoichiometric conditions.
Enantioselective Hydroformylation of Aniline Derivatives

We have developed a ligand that reversibly binds to aniline substrates, allowing for the control of regioselectivity and enantioselectivity in hydroformylation. In this paper we address how the electronics of the aniline ring affect both the binding of the substrate to the ligand and the enantioselectivity in this reaction.
Vortex-induced motions of a tethered sphere

Abstract Despite the practical significance of studying the vibrations of a tethered sphere in a steady fluid flow, there are almost no laboratory investigations of such a problem, and it was previously unknown whether such a system would tend to oscillate or not. The present work demonstrates that a tethered sphere will oscillate vigorously, at a peak-to-peak amplitude of about two diameters, over a large range of velocities. The RMS amplitude of these oscillations is found to be independent of the tether length when plotted against the reduced velocity VR = U/fnD. However, the saturation value of the RMS is found to vary with the mass ratio. Also interesting is the observed oscillation frequency, at low mass ratios, which does not correspond to either the natural frequency nor the sphere vortex shedding frequency (in the absence of vibrations). The observed large amplitude oscillations also induce an increase in drag and tether angle of the order of 100% The above results suggest that oscillations are highly significant to predictions of sphere response in a steady flow, and should not be neglected.
Non-Abelian two-component fractional quantum Hall states

A large class of fractional quantum Hall (FQH) states can be classified according to their pattern of zeros, which describes the order of zeros in ground state wave functions as various clusters of electrons are brought together. The pattern-of-zeros approach can be generalized to systematically classify multilayer/spin-unpolarized FQH states, which has led to the construction of a class of non-Abelian multicomponent FQH states. Here we discuss some of the simplest non-Abelian two-component states that we find and the possibility of their experimental realization in bilayer systems at $\nu = 2/3$, 4/5, 4/7, 4/9, 1/4, etc.
Frozen Gaussian approximation for high frequency wave propagation

We propose the frozen Gaussian approximation for computation of high frequency wave propagation. This method approximates the solution to the wave equation by an integral representation. It provides a highly ef- ficient computational tool based on the asymptotic analysis on phase plane. Compared to geometric optics, it provides a valid solution around caustics. Compared to the Gaussian beam method, it overcomes the drawback of beam spreading. We give several numerical examples to verify that the frozen Gauss- ian approximation performs well in the presence of caustics and when the Gaussian beam spreads. Moreover, it is observed numerically that the frozen Gaussian approximation exhibits better accuracy than the Gaussian beam method.
Evolution of variance in offspring number: the effects of population size and migration.

It was shown by Gillespie [1974. Am. Nat. 108, 145–151], that if two genotypes produce the same average number of offspring on but have a different variance associated within each generation, the genotype with a lower variance will have a higher effective fitness. Specifically, the effective fitness is {ei65-1}, where w is the mean fitness, {ei65-2} is the variance in offspring number, and N is the total population size. The model also predicts that if a strategy has a higher arithmetic mean fitness and a higher variance than the competitor, the outcome of selection will depend on the population size (with larger population sizes favoring the highvariance, high-mean genotype). This suggests that for metapopulation sizes favoring the high-variance, high-mean genotype). This suggests that for metapopulations with large numbers of (relatively) small demes, a strategy with lower variance and lower mean may be favored if the migration rate is low while higher migration rates (consistent with a larger effective population size) favor the opposite strategy. Individual-based simulation confirms that this is indeed the case for an island model of migration, though the effect of migration differs greatly depending on whether migration precedes or follows selection. It is noted in the appendix that while Gillespie [1974. Am. Nat. 108, 145–151] does seem to be heuristically accurate, it is not clear that the definition of effective fitness follows from his derivation.
UPTAKE OF [3H]-COLCHICINE INTO BRAIN AND LIVER OF MOUSE, RAT, AND CHICK

The uptake of [ring A-4-3H] colchicine and [ring C-methoxy-3H]colchicine has been compared in mice from 1 to 24 hr after administration. Less radioactivity was found in brain after administration of ring-labeled colchicine than after administration of the methoxy-labeled colchicine. Three hr after administration of ring-labeled colchicine, 5% of the label was in liver and about 0.01% of the label was present in brain. Forty percent of the brain radioactivity was bound to tubulin as determined by vinblastine precipitation. After 3 hr, an average of 8% of the radioactivity from methoxy-labeled colchicine was found in the liver and 0.16% in brain. However, less than 5% of the activity in brain was precipitated by vinblastine, and the colchicine equivalent was comparable to that found after administration of the ring-labeled colchicine. The amount of colchicine entering mouse brain after subcutaneous injection is comparable to the minimum behaviorally effective dose when administered to the caudate. The metabolism of [ring C-methoxy-3H] and [ring A-3H]colchicine was also studied in rats. The general pattern was similar to mice; less radioactivity was found in brain after administration of the ring-labeled alkaloid than after administration of methoxy-labeled colchicine. Again, 40-50% of ring-labeled colchicine was precipitated by vinblastine. A much smaller percentage of the methoxy-labeled drug was precipitated by vinblastine than of the ring A-labeled colchicine. These experiments, together with behavioral experiments [7], support the hypotheses that structural alterations in synapses by recently synthesized proteins which are transported down the axons and dendrites may be an essential process for long-term memory formation.
Ultrafast direct modulation of a single-mode photonic crystal nanocavity light-emitting diode

We demonstrate an electrically driven single mode photonic crystal cavity LED with record speed of operation (10 GHz) and 0.25 fJ/bit energy consumption, the lowest of any optical transmitter to date.
Characteristics of fluid flow in the combustion synthesis of TiC from the elements

The results of a numerical investigation of finite reservoir effects on capillary spreading at small reservoir dimensions are presently related to wave propagation phenomena in the combustion synthesis of TiC from its two elemental constituents. It is noted that gravitational forces can affect bubble coalescence by nonbuoyant means under the suitable conditions, although these conditions are expected to be rare in combustion synthesis. Finite-curved reservoirs can drive capillary flow due to surface tension and wall contact forces; these cause the wall and the metal to be completely reconfigured during combustion synthesis.
Motivic Integration on Toric Stacks

We present a decomposition of the space of twisted arcs of a toric stack. As a consequence, we give a combinatorial description of the motivic integral associated to a torus-invariant divisor of a toric stack.
Parameterized longest previous factor

Given a string W, the longest previous factor (LPF) problem is to determine the maximum length of a previously occurring factor for each suffix occurring in W. The LPF problem is defined for traditional strings exclusively from the constant alphabet @S. A parameterized string (p-string) is a string composed of symbols from a constant alphabet @S and a parameter alphabet @P. We formulate the LPF problem in terms of p-strings by defining the parameterized longest previous factor (pLPF) problem. Subsequently, we present an expected linear time solution to construct the parameterized longest previous factor (pLPF) array. Given our pLPF solution, we show how to construct the pLCP (parameterized longest common prefix) array with the same general algorithm. We exploit the properties of the pLPF data structure to also construct the standard LPF (longest previous factor) and LCP (longest common prefix) arrays all in linear time. Further, we provide insight into the practicality of our construction algorithms.
Electron scattering: A microscope for nuclear and nucleon structure

Abstract We review progress and assess the outlook for investigations of the structure of nuclei and nucleons using electron scattering.
The quantum query complexity of approximating the median and related statistics

Let X = (x_0,...,x_{n-1})$ be a sequence of n numbers. For \epsilon > 0, we say that x_i is an \epsilon-approximate median if the number of elements strictly less than x_i, and the number of elements strictly greater than x_i are each less than (1+\epsilon)n/2. We consider the quantum query complexity of computing an \epsilon-approximate median, given the sequence X as an oracle. We prove a lower bound of \Omega(\min{{1/\epsilon},n}) queries for any quantum algorithm that computes an \epsilon-approximate median with any constant probability greater than 1/2. We also show how an \epsilon-approximate median may be computed with O({1/\epsilon}\log({1\/\epsilon}) \log\log({1/\epsilon})) oracle queries, which represents an improvement over an earlier algorithm due to Grover. Thus, the lower bound we obtain is essentially optimal. The upper and the lower bound both hold in the comparison tree model as well. Our lower bound result is an application of the polynomial paradigm recently introduced to quantum complexity theory by Beals et al. The main ingredient in the proof is a polynomial degree lower bound for real multilinear polynomials that ``approximate'' symmetric partial boolean functions. The degree bound extends a result of Paturi and also immediately yields lower bounds for the problems of approximating the kth-smallest element, approximating the mean of a sequence of numbers, and that of approximately counting the number of ones of a boolean function. All bounds obtained come within polylogarithmic factors of the optimal (as we show by presenting algorithms where no such optimal or near optimal algorithms were known), thus demonstrating the power of the polynomial method.
Video chat with multiple cameras

This work provides the first rigorous investigation of multi-camera video chat, concentrating especially on the ability of a user at one end of the conversation to switch between multiple views at both ends of the conversation. A user study of 23 individuals and comprehensive benchmark experiments employing up to four webcams simultaneously demonstrate that multi-camera video chat is both desirable and feasible on consumer hardware.
Nanoparticle conversion chemistry: Kirkendall effect, galvanic exchange, and anion exchange

Conversion chemistry is a rapidly maturing field, where chemical conversion of template nanoparticles (NPs) into new compositions is often accompanied by morphological changes, such as void formation. The principles and examples of three major classes of conversion chemical reactions are reviewed: the Kirkendall effect for metal NPs, galvanic exchange, and anion exchange, each of which can result in void formation in NPs. These reactions can be used to obtain complex structures that may not be attainable by other methods. During each kind of conversion chemical reaction, NPs undergo distinct chemical and morphological changes, and insights into the mechanisms of these reactions will allow for improved fine control and prediction of the structures of intermediates and products. Conversion of metal NPs into oxides, phosphides, sulphides, and selenides often occurs through the Kirkendall effect, where outward diffusion of metal atoms from the core is faster than inward diffusion of reactive species, resulting in void formation. In galvanic exchange reactions, metal NPs react with noble metal salts, where a redox reaction favours reduction and deposition of the noble metal (alloying) and oxidation and dissolution of the template metal (dealloying). In anion exchange reactions, addition of certain kinds of anions to solutions containing metal compound NPs drives anion exchange, which often results in significant morphological changes due to the large size of anions compared to cations. Conversion chemistry thus allows for the formation of NPs with complex compositions and structures, for which numerous applications are anticipated arising from their novel catalytic, electronic, optical, magnetic, and electrochemical properties.
Stereospecific Synthesis of Conformationally Constrained γ-Amino Acids: New Foldamer Building Blocks That Support Helical Secondary Structure

A highly stereoselective synthesis of novel cyclically constrained γ-amino acid residues is presented. The key step involves organocatalytic Michael addition of an aldehyde to 1-nitrocyclohexene. After aldehyde reduction, this approach provides optically active β-substituted δ-nitro alcohols (96−99% ee), which can be converted to γ-amino acid residues with a variety of substituents at the α position. We have used these new building blocks to prepare α/γ-peptide foldamers that adopt a specific helical conformation in solution and in the solid state.
GALVANOTROPISM AND "REVERSAL OF INHIBITION" BY STRYCHNINE

The cathodically galvanotropic orientation of nemerteans, Lineus, and the anodic orientation of the gephyrean Echiurus, are reversed by the action of strychnine under conditions such that the typical "reversal of inhibition" induced by this substance is apparent. Nicotine does not give this result. Since it is necessary to assume that the strychnine effect is due to action upon the central ganglia, and since the galvanotropic effect depends upon action of the current on nerve cell bodies of the central ganglia, it must be assumed that the locus of reversal by strychnine is not perikaryal, but presumably synaptic.
Nilpotent slices, Hilbert schemes, and the Jones polynomial

Seidel and Smith [33] have constructed an invariant of links as the Floer cohomology for two Lagrangians inside a complex affine variety Y. This variety is the intersection of a semisimple orbit with a transverse slice at a nilpotent in the Lie algebra sl2m. We exhibit bijections between a set of generators for the Seidel-Smith cochain complex, the generators in Bigelow's picture of the Jones polynomial, and the generators of the Heegaard Floer cochain complex for the double branched cover. This is done by presenting Y as an open subset of the Hilbert scheme of a Milnor fiber
Circular symmetry in topologically massive gravity

We re-derive, compactly, a topologically massive gravity (TMG) decoupling theorem: source-free TMG separates into its Einstein and Cotton sectors for spaces with a hypersurface-orthogonal Killing vector, here concretely for circular symmetry. We then generalize the theorem to include matter; surprisingly, the single Killing symmetry also forces conformal invariance, requiring the sources to be null.
Spontaneous fission of atmospheric aerosol particles

We show that spontaneous division of atmospheric aerosol particles is thermodynamically possible, in spite of the corresponding increase in surface area, when there is a highly compressed organic surfactant coating on the particle. This class of atmospheric aerosol is thought to be present (and potentially important) in both marine and urban atmospheres. Fully-coated particles have been suggested to have played a role in the origin of cell-based life. The possibility of their spontaneous division has important implications for atmospheric chemistry, radiative transfer and the evolution of life on Earth.
A closed-loop anesthetic delivery system for real-time control of burst suppression.

Objective. There is growing interest in using closed-loop anesthetic delivery (CLAD) systems to automate control of brain states (sedation, unconsciousness and antinociception) in patients receiving anesthesia care. The accuracy and reliability of these systems can be improved by using as control signals electroencephalogram (EEG) markers for which the neurophysiological links to the anesthetic-induced brain states are well established. Burst suppression, in which bursts of electrical activity alternate with periods of quiescence or suppression, is a well-known, readily discernible EEG marker of profound brain inactivation and unconsciousness. This pattern is commonly maintained when anesthetics are administered to produce a medically-induced coma for cerebral protection in patients suffering from brain injuries or to arrest brain activity in patients having uncontrollable seizures. Although the coma may be required for several hours or days, drug infusion rates are managed inefficiently by manual adjustment. Our objective is to design a CLAD system for burst suppression control to automate management of medically-induced coma. Approach. We establish a CLAD system to control burst suppression consisting of: a two-dimensional linear system model relating the anesthetic brain level to the EEG dynamics; a new control signal, the burst suppression probability (BSP) defining the instantaneous probability of suppression; the BSP filter, a state-space algorithm to estimate the BSP from EEG recordings; a proportional–integral controller; and a system identification procedure to estimate the model and controller parameters. Main results. We demonstrate reliable performance of our system in simulation studies of burst suppression control using both propofol and etomidate in rodent experiments based on Vijn and Sneyd, and in human experiments based on the Schnider pharmacokinetic model for propofol. Using propofol, we further demonstrate that our control system reliably tracks changing target levels of burst suppression in simulated human subjects across different epidemiological profiles. Significance. Our results give new insights into CLAD system design and suggest a control-theory framework to automate second-to-second control of burst suppression for management of medically-induced coma.
CLASSICAL DYNAMICS FOR LINEAR SYSTEMS: THE CASE OF QUANTUM BROWNIAN MOTION

The dynamics of linear quantum systems is classical in the Wigner representation, yet linear problems are often analyzed using such general techniques as influence functionals and Bogoliubov transformations. In fact, the classical equations of motion provide a simpler and more intuitive formalism for these systems. As an important example, we show that quantum Brownian dynamics in the independent oscillator model is described directly and completely by a c-number Langevin equation. The corresponding Fokker-Planck equation is always local in time, regardless of the environmental spectrum.
Electronic structure and magnetism of CuNi coherent modulated structures

The electronic structure and magnetism of coherent modulated structures of CuNi for varying numbers of Cu and Ni layers modulated along [111] and [100] directions has been determined theoretically by means of self‐consistent spin polarized LMTO energy band studies and compared with experiment and with theoretical results separately obtained for bulk fcc and tetragonally distorted Ni metal. The magnetic moments in the Ni layers in CuNi are found to be reduced relative to that of fcc Ni indicating that the enhanced magnetism deduced from earlier ferromagnetic resonance observations must arise from other sources. These predictions have been confirmed recently by direct magnetization and neutron magnetic scattering studies.
Technology for the design of high temperature rise combustors

The results of analytical and experimental studies to determine the design technology needs of high temperature rise (AT) combustors and to define candidate design concepts for meeting these needs are reviewed. These studies show that several unique design considerations and constraints apply, because a high proportion of the available airflow must be allocated to the combustion process at the high AT operating conditions. This airflow allocation is necessary to obtain efficient combustion and acceptable smoke emission levels at the high AT conditions. Important technology needs include design features to provide stable operation over very wide AT ranges and design features to minimize liner-cooling airflow requirements. Candidate design concept features for providing these needed high A J combustor capabilities are described. Included are advanced design concepts to provide combustion process staging capabilities, as well as advanced liner-cooling and structural design concepts. The current development status of these various advanced design concepts is also assessed.
Highly Regio- and Stereoselective Synthesis of (Z)-Trisubstituted Alkenes via Propyne Bromoboration and Tandem Pd-Catalyzed Cross-Coupling

Contrary to all previous reports, bromoboration of propyne with BBr3 proceeds in ≥98% syn-selectivity to produce (Z)-2-bromo-1-propenyldibromoborane (1). Although 1 is readily prone to stereoisomerization, it can be converted to the pinacolboronate (2) of ≥98% isomeric purity by treatment with pinacol, which may then be subjected to Negishi coupling to give trisubstituted (Z)-alkenylpinacolboronates (3) containing various R groups in 73−90% yields. Iodinolysis of 3 affords alkenyl iodides (4) in 80−90% yields. All alkenes isolated and identified are ≥98% Z.
CsAg5Te3: a new metal-rich telluride with a unique tunnel structure

Abstract The synthesis and structure of a new ternary silver telluride, CsAg5Te3, is described. The compound was prepared from a Cs2Te CaTe Te flux but it can also be prepared from a direct combination of Cs2Te and Ag2Te under vacuum at 600 °C. The crystal data for CsAg5Te3 at 20 °C (Mo Kα radiation) are as follows: a = 14.672(2)Aandc = 4.601(3)A; V = 990.5(8)A3; Z = 4; Dcalc = 7.075 g cm−3; space group, P42/mnm (No. 136); 2θmax = 50°; number of independent data collected, 572; number of data observed with I > 3σ(I), 267; number of variables, 32; μ = 218.51 cm−1; extinction coefficient, 0.585 × 10−7; final R = 0.040; Rw = 0.046; goodness of fit, 1.42. The compound features a new structure type with Cs+-filled, relatively large tunnels running through the lattice. The material is a semiconductor with a band gap of about 0.65 eV.
Local Capture: Evidence from a Central Government Transfer Program in Uganda

According to official statistics, 20 percent of Uganda's total public expenditure was spent on education in the mid-1990s, most of it on primary education. One of the large public programs was a capitation grant to cover schools' nonwage expenditures. Using panel data from a unique survey of primary schools, we assess the extent to which the grant actually reached the intended end-user (schools). The survey data reveal that during 1991–1995, the schools, on average, received only 13 percent of the grants. Most schools received nothing. The bulk of the school grant was captured by local officials (and politicians). The data also reveal considerable variation in grants received across schools, suggesting that rather than being passive recipients of flows from the government, schools use their bargaining power to secure greater shares of funding. We find that schools in better-off communities managed to claim a higher share of their entitlements. As a result, actual education spending, in contrast to budget allocations, is regressive. Similar surveys in other African countries confirm that Uganda is not a special case.
Harmonic analysis of signed Ruelle transfer operators

Abstract Motivated by wavelet analysis, we prove that there is a one-to-one correspondence between the following data: (i) Solutions to R(h)=h where R is a certain non-positive Ruelle transfer operator; (ii) Operators that intertwine a certain class of representations of the C ∗ -algebra A N on two unitary generators U , V subject to the relation UVU −1 =V N . This correspondence enables us to give a criterion for the biorthogonality of a pair of scaling functions and calculate all solutions of the equation R(h)=h in some concrete cases.
Permutation polytopes and indecomposable elements in permutation groups

Each group G of n × n permutation matrices has a corresponding permutation polytope, P(G) := conv(G) ⊂ Rn × n. We relate the structure of P(G) to the transitivity of G. In particular, we show that if G has t nontrivial orbits, then min{2t, ⌊n/2⌋} is a sharp upper bound on the diameter of the graph of P(G). We also show that P(G) achieves its maximal dimension of (n - 1)2 precisely when G is 2-transitive. We then extend the results of Pak [I. Pak, Four questions on Birkhoff polytope, Ann. Comb. 4 (1) (2000) 83-90] on mixing times for a random walk on P(G). Our work depends on a new result for permutation groups involving writing permutations as products of indecomposable permutations.
Kulokekahilide-1, a Cytotoxic Depsipeptide from the Cephalaspidean Mollusk Philinopsis speciosa

The cytotoxic depsipeptide kulokekahilide-1, which contains two unusual amino acids, 4-phenylvaline and 3-amino-2-methylhexanoic acid, was isolated from the cephalaspidean mollusk Philinopsis speciosa. Structure elucidation of kulokekahilide-1 was carried out by spectroscopic analysis and chemical degradation. The absolute stereochemistry was determined by Marfey analysis for amino acids and chiral HPLC analysis for hydroxy acids. All four stereoisomers of 4-phenylvaline and 3-amino-2-methylhexanoic acid, which were necessary for Marfey analysis, were synthesized by use of the Heck reaction and Evans's method, respectively. Kulokekahilide-1 showed cytotoxicity against P388 murine leukemia cells with an IC50 value of 2.1 μg/mL.
Addressing causality in the effect of capital account liberalization on growth

Abstract Evidence supporting the positive effects of capital account liberalization on growth is mixed at best. Even after conditioning on the quality of domestic financial institutions, a significant number of studies still find no effect. One possible explanation is reverse causation. If low growth countries liberalize in order to spur growth, the observed correlation between growth and liberalization will underestimate the impact of capital account openness. To eliminate this bias, I instrument capital account liberalization with the average level of openness of other countries to capture the “fad” element in financial liberalization. IV estimates indicate a significant positive effect of liberalization on growth, confirming the predictions of economic theory.
High-concentration mirror-based Kohler integrating system for tandem solar cells

A novel two-mirror high concentration nonimaging optic has been designed that shares the advantages of present two mirror aplanatic imaging concentrators but also overcomes their main limitation of trade-off between acceptance angle and irradiance uniformity. A system concept has been defined, and a first prototype in under development.
Site-specific C-terminal and internal loop labeling of proteins using sortase-mediated reactions

Methods for site-specific modification of proteins should be quantitative and versatile with respect to the nature and size of the biological or chemical targets involved. They should require minimal modification of the target, and the underlying reactions should be completed in a reasonable amount of time under physiological conditions. Sortase-mediated transpeptidation reactions meet these criteria and are compatible with other labeling methods. Here we describe the expression and purification conditions for two sortase A enzymes that have different recognition sequences. We also provide a protocol that allows the functionalization of any given protein at its C terminus, or, for select proteins, at an internal site. The target protein is engineered with a sortase-recognition motif (LPXTG) at the place where modification is desired. Upon recognition, sortase cleaves the protein between the threonine and glycine residues, facilitating the attachment of an exogenously added oligoglycine peptide modified with the functional group of choice (e.g., fluorophore, biotin, protein or lipid). Expression and purification of sortase takes ∼3 d, and sortase-mediated reactions take only a few minutes, but reaction times can be extended to increase yields.
Nanoparticle Shape Selectivity in Catalysis: Butene Isomerization and Hydrogenation on Platinum

New advances in colloidal and other self-assembly synthetic methods have afforded the controlled growth of nanoparticles with well-defined sizes and shapes. Recently, the catalysis community has been trying to capitalize on this knowledge for the design of new catalytic processes. In particular, the use of metal nanoparticles with specific shapes has been explored in several instances as a way to control reaction selectivity. Here we review the results from our efforts to use platinum nanoparticles dispersed on high-surface-area supports to perform selective olefin conversions. Emphasis is given to the surface-science experiments and quantum-mechanics calculations that led us to identify potential variations in selectivity in carbon–carbon double-bond isomerization and hydrogenation reactions with the structure of the metal surface. Temperature programmed desorption (TPD) and reflection–absorption infrared spectroscopy data for 2-butenes adsorbed on Pt(111) single-crystal surfaces highlighted the relative higher stability of adsorbed cis-2-butene compared to trans-2-butene and the preference for the promotion of trans-to-cis conversions on that surface. It was also determined that coadsorbed hydrogen plays a key role in defining the relative stabilities of the adsorbates, favoring pi rather than di-sigma bonding and reversing the higher stability of the trans adsorbates seen on clean Pt(111). DFT calculations suggested that such unique results may be accounted for by the need for extensive surface reconstruction to accommodate the adsorbates on such flat planes, a requirement that appears to be less severe with the cis isomer. TPD experiments on stepped Pt(557) surfaces pointed to the minimal importance of steps in promoting these isomerization reactions, although they do seem to help with the full hydrogenation to the alkanes. More extensive olefin adsorption destabilization with hydrogen coadsorption and faster alkane production was seen on Pt(100), but selectivity towards the cis isomer was still identified. On the more open (2 × 1)-reconstructed Pt(110) surface, on the other hand, trans-2-butene is the most stable of the two isomers. It was finally shown that these surface-science results translate into changes in selectivity in real catalysts with platinum nanoparticle shape. Catalysts were prepared by using colloidal Pt nanoparticles with tetrahedral, cubic, and rounded shapes, and unique selectivity toward cis-2-butene formation was measured on the first of those samples. It appears that the (111) facets exposed by the tetrahedral Pt nanoparticles do show the same trans-to-cis conversion preference in catalysis seen in the surface-science studies carried out with single-crystal surfaces and under ultrahigh vacuum conditions.
Little hierarchy, little higgses, and a little symmetry

Little Higgs theories are an attempt to address the ``little hierarchy problem,'' i.e., the tension between the naturalness of the electroweak scale and the precision electroweak measurements showing no evidence for new physics up to 5 – 10 TeV. In little Higgs theories, the Higgs mass-squareds are protected at one-loop order from the quadratic divergences. This allows the cutoff of the theory to be raised up to ~ 10 TeV, beyond the scales probed by the current precision data. However, strong constraints can still arise from the contributions of the new TeV scale particles which cancel the one-loop quadratic divergences from the standard model fields, and hence re-introduces the fine-tuning problem. In this paper we show that a new symmetry, denoted as T-parity, under which all heavy gauge bosons and scalar triplets are odd, can remove all the tree-level contributions to the electroweak observables and therefore makes the little Higgs theories completely natural. The T-parity can be manifestly implemented in a majority of little Higgs models by following the most general construction of the low energy effective theory a la Callan, Coleman, Wess and Zumino. In particular, we discuss in detail how to implement the T-parity in the littlest Higgs model based on SU(5)/SO(5). The symmetry breaking scale f can be even lower than 500 GeV if the contributions from the higher dimensional operators due to the unknown UV physics at the cutoff are somewhat small. The existence of T-parity has drastic impacts on the phenomenology of the little Higgs theories. The T-odd particles need to be pair-produced and will cascade down to the lightest T-odd particle (LTP) which is stable. A neutral LTP gives rise to missing energy signals at the colliders which can mimic supersymmetry. It can also serve as a good dark matter candidate.
(±)-3′-deoxyaraaristeromycin via a surprising rearrangement

Abstract Hydrolysis of (+)-3β-acetoxy-4α-benzamido-1α- cyclopentanemethyl acetate ( 5 ) with 6 N hydrochloric acid has been found to give an amine in which the configuration at C-3 has been inverted. This conclusion was reached following conversion of the amine into (+)-3′-deoxyaraaristeromycin ( 8 ) by following a standard adenine formation process of (i) reaction with 5-amino-4,6-dichlocopyrimidine, (ii) ring closure with diethoxymethyl acetate, and (iii) ammonolysis. Use of basic hydrolysis conditions with 5 led to the expected (+)3′deoxyaristeromycin ( 7 ).
Nonlocal charge transport mediated by spin diffusion in the spin Hall effect regime

A nonlocal electric response in the spin Hall regime, resulting from spin diffusion mediating charge conduction, is predicted. The spin-mediated transport stands out due to its long-range character, and can give dominant contribution to nonlocal resistance. The characteristic range of nonlocality, set by the spin diffusion length, can be large enough to allow detection of this effect in materials such as GaAs despite its small magnitude. The detection is facilitated by a characteristic nonmonotonic dependence of transresistance on the external magnetic field, exhibiting sign changes and decay.
Exact Results for Supersymmetric Renormalization and the Supersymmetric Flavor Problem

We explore the effects of a strongly-coupled, approximately scale-invariant sector on the renormalization of soft supersymmetry breaking terms. A useful formalism for deriving exact results for renormalization of soft supersymmetry breaking terms is given in an appendix, and used to generalize previously known results to include the effects of nontrilinear superpotential terms. We show that a class of theories which explain the flavor hierarchy without flavor symmetries can also solve the supersymmetric flavor problem by producing nearly degenerate masses for the first two generations of scalar superpartners within each charge sector. Effects from trilinear scalar terms are also suppressed, although their initial values must be relatively small. Our mechanism results in testable predictions for the superpartner spectrum.
Particle production in strong electromagnetic fields in relativistic heavy-ion collisions

I review the origin and properties of electromagnetic fields produced in heavy-ion collisions. The field strength immediately after a collision is proportional to the collision energy and reaches &#x7e; at RHIC and &#x7e; at LHC. I demonstrate by explicit analytical calculation that after dropping by about one-two orders of magnitude during the first fm/c of plasma expansion, it freezes out and lasts for as long as quark-gluon plasma lives as a consequence of finite electrical conductivity of the plasma. Magnetic field breaks spherical symmetry in the direction perpendicular to the reaction plane, and therefore all kinetic coefficients are anisotropic. I examine viscosity of QGP and show that magnetic field induces azimuthal anisotropy on plasma flow even in spherically symmetric geometry. Very strong electromagnetic field has an important impact on particle production. I discuss the problem of energy loss and polarization of fast fermions due to synchrotron radiation, consider photon decay induced by magnetic field, elucidate dissociation via Lorentz ionization mechanism, and examine electromagnetic radiation by plasma. I conclude that all processes in QGP are affected by strong electromagnetic field and call for experimental investigation.
Twin-jet screech suppression

A facility test was performed on twin-jet configurations to determine the effectiveness of several concepts in suppressing the supersonic screech tones. Supersonic jet Mach numbers up to 1.75 were tested. The screech suppression concepts were tabs, lateral spacing, axial spacing, and secondary air jets. Acoustic and optical data were obtained. It was found that the twin-jet configuration can result in screech tone amplitudes as much as 20 dB higher than a single jet. Screech tone amplitudes up to 162 dB were measured. Small tabs located at the exit plane were shown to be very effective suppressors if they were large enough or if multiple tabs were installed. Lateral spacing can result in significant tone suppression, however, at certain spacings little suppression was achieved. Axial spacing resulted in essentially no suppression. The secondary air jet was shown to be a very effective suppressor of screech tones from a single jet but was not tested on the twin jet configuration.
Primacy Effects and the Role of Risk in Auditor Belief‐Revision Processes

Numerous studies in the audit judgment literature provide evidence indicating that auditors can be susceptible to recency effects. This study extends the research by examining auditor susceptibility to primacy, an order effect, which, like recency, can lead to suboptimal audit‐planning decisions (see Ashton and Ashton 1988) and yet, unlike recency, has received very little attention in the accounting literature. Specifically, the research investigates whether primacy effects in auditor belief revisions are a conditional function of the level of inherent risk present in the audit environment (high/low) and the nature of the information contained in the latter portion of the information sequence (e.g., whether the information is positive or negative with respect to the client's internal controls). The results, consistent with expectations, indicate that auditors are susceptible to primacy effects when making likelihood of error and audit‐hour planning judgments in settings that are relatively low in inheren...
Under the Cover of Antidumping: Does Administered Protection Facilitate Domestic Collusion?

Anecdotal evidence suggests that domestic firms can use the antidumping petition process to engage in collusion and increase domestic prices. In this paper, I test whether the antidumping petition process itself can help domestic firms raise prices. I propose a method to identify whether firms in the industry experience a structural break in the level of market power possessed by the firms at the time that they file their antidumping petition. I use this methodology to analyze the impact of antidumping petitions on competition levels in two industries. I find little evidence that either of these industries increased their market power following the filing of petitions for trade relief, nor even from the protection that resulted from these petitions. These findings suggest that the widespread belief that antidumping leads to more market power may not always hold.
The "practical significance" of Locke's theory of goal setting.

The practical significance of Locke’s theory of goal setting was assessed using a time series design. Data on the net weight of 36 logging trucks in six logging operations were collected for 12 consecutive months. Performance improved immediately upon the assignment of a specific hard goal. Company cost accounting procedures indicated that this same increase in performance without goal setting would have required an expenditure of a quarter of a million dollars on the purchase of additional trucks alone.
Clay Dispersion Effects on Excimer Laser Ablation of Polymer-Clay Nanocomposites

The ablation behavior of polystyrene-organically modified montmorillonite (OMMT) nanocomposites was evaluated by measuring the weight loss induced by KrF excimer laser irradiation of the nanocomposite specimens under air atmosphere. The characteristic values of ablation, ablation threshold fluence, and effective absorption coefficient for polystyrene and its nanocomposites were calculated based on the weight loss data. The effects of morphology due to spatial variation in injection molded samples are also discussed in this article. Results demonstrate that both the dispersion state and the concentration of clay play important roles in excimer laser ablation. The sensitivity of threshold fluence and absorption coefficient to dispersion state of OMMT seem to depend on the clay concentration. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2336–2344, 2013
Control of Shape Memory Alloy Actuators Using Pulse-Width Pulse-Frequency (PWPF) Modulation:

This paper presents the design and experimental results of control of a Shape Memory Alloy (SMA) actuator using Pulse-Width Pulse-Frequency (PWPF) modulation to reduce the energy consumption of the SMA actuator. An SMA wire test stand is used in this research. Based on results of open-loop testing of the SMA wire actuator and parameter analysis of the PWPF modulator, a PWPF modulator is designed to modulate a Proportional plus Derivative (PD) controller. Experiments demonstrate that control of the SMA actuator using PWPF modulation effectively save actuation energy while maintaining same control accuracy as compared to continuous PD control.
Inventing the Cosmo Girl: Class Identity and Girl‐Style American Dreams

Since the mid-1970s, Helen Gurley Brown has been a cultural icon as well as the editor of the hugely profitable Cosmopolitan magazine. Following a cultural studies approach to media historiography, this article traces Brown's rise to fame and analyzes her early advice to women as a `cultural discourse' that managed some of the social and economic tensions of the early 1960s and early 1970s, while also offering certain women the symbolic material to think about themselves as historical subjects in new ways. Brown is often remembered as the feminine piper in the `sexual revolution' of the 1960s, but I suggest that her girl-style American Dream promised transcendence from class roles as much as sexual ones. Brown's early advice to women offers a case study in the cultural construction of class as a fragmented, socially constituted and sexualized identity.
RANDOM COVARIANCE MATRICES: UNIVERSALITY OF LOCAL STATISTICS OF EIGENVALUES UP TO THE EDGE

We study the universality of the eigenvalue statistics of the covariance matrices $\frac{1}{n}M^* M$ where M is a large p × n matrix with independent entries that have mean zero, variance one and sufficiently high finite moments. In particular, as an application, we prove a variant of universality results regarding the smallest singular value of Mp, n. This paper is an extension of the results of Tao and Vu (2009) from the bulk of the spectrum up to the edge.
Acquired Aplastic Anemia

In aplastic anemia, hematopoiesis fails: Blood cell counts are extremely low, and the bone marrow appears empty. The pathophysiology of aplastic anemia is now believed to be immune-mediated, with active destruction of blood-forming cells by lymphocytes. The aberrant immune response may be triggered by environmental exposures, such as to chemicals and drugs or viral infections and, perhaps, endogenous antigens generated by genetically altered bone marrow cells. In patients with post-hepatitis aplastic anemia, antibodies to the known hepatitis viruses are absent; the unknown infectious agent may be more common in developing countries, where aplastic anemia occurs more frequently than it does in the West. The syndrome paroxysmal nocturnal hemoglobinuria (PNH) is intimately related to aplastic anemia because many patients with bone marrow failure have an increased population of abnormal cells. In PNH, an entire class of proteins is not displayed on the cell surface because of an acquired X-chromosome gene mutation. The PNH cells may have a selective advantage in resisting immune attack. In contrast, the disease myelodysplasia can be confused with aplasia and can also evolve from aplastic anemia. The occurrence of cytogenetic abnormalities in patients years after presentation implies that genomic instability is a feature of this immune-mediated disease. Aplastic anemia can be effectively treated by stem-cell transplantation or immunosuppressive therapy. Transplantation is curative but is best used for younger patients who have histocompatible sibling donors. Antithymocyte globulin and cyclosporine restore hematopoiesis in approximately two thirds of patients. However, recovery of blood cell count is often incomplete, recurrent pancytopenia requires retreatment, and some patients develop late complications (especially myelodysplasia).