cssi/SciSciGPT-SciSciNet huggingface dataset:
Star Formation and Feedback in Dwarf Galaxies

We examine the star formation history and stellar feedback effects of dwarf galaxies under the influence of extragalactic ultraviolet radiation. Previous work has indicated that the background UV flux can easily ionize the gas within typical dwarf galaxies, delaying or even preventing cooling and star formation within them. Many dwarf galaxies within the Local Group are, however, observed to contain multiple generations of stars, the oldest of which formed in the early epochs of cosmic evolution, when the background UV flux was intense. In order to address this paradox, we consider the dynamical evolution of gas in dwarf galaxies using a one-dimensional, spherically symmetric, Lagrangian numerical scheme to compute the effects of radiative transfer and photoionization. We include a physically motivated star formation recipe and consider the effects of feedback. This scheme allows us to follow the history of the gas and of star formation within dwarf galaxies, as influenced by both external and internal UV radiation. Our results indicate that star formation in the severe environment of dwarf galaxies is a difficult and inefficient process. In potentials with total mass less than a few times 106 M☉ and velocity dispersion less than a few kilometers per second, residual gas is efficiently photoionized by cosmic background UV radiation. Since the density scale height of the gas within these galaxies is comparable to their size, gas may be tidally removed from them, leaving behind starless residual dark matter clumps. For intermediate-mass systems, such as the dSphs around the Galaxy, star formation can proceed within early cosmic epochs despite the intense background UV flux. Triggering processes such as merger events, collisions, and tidal disturbance can lead to density enhancements, reducing the recombination timescale, allowing gas to cool and star formation to proceed. However, the star formation and gas retention efficiency may vary widely in galaxies with similar dark matter potentials because they depend on many factors, such as the baryonic fraction, external perturbation, initial mass function, and background UV intensity. We suggest that the presence of very old stars in these dwarf galaxies indicates that their initial baryonic-to-dark matter content was comparable to the cosmic value. This constraint suggests that the initial density fluctuation of baryonic matter may be correlated with that of the dark matter. For the more massive dwarf elliptical galaxies, the star formation efficiency and gas retention rate are much higher. Their mass-to-light ratio is regulated by star formation feedback and is expected to be nearly independent of their absolute luminosity. The results of our theoretical models reproduce the observed (M/L)-Mv correlation.
Conjoining Speeds up Information Diffusion in Overlaying Social-Physical Networks

We study the diffusion of information in an overlaying social-physical network. Specifically, we consider the following set-up: There is a physical information network where information spreads amongst people through conventional communication media (e.g., face-to-face communication, phone calls), and conjoint to this physical network, there are online social networks where information spreads via web sites such as Facebook, Twitter, FriendFeed, YouTube, etc. We quantify the size and the critical threshold of information epidemics in this conjoint social-physical network by assuming that information diffuses according to the SIR epidemic model. One interesting finding is that even if there is no percolation in the individual networks, percolation (i.e., information epidemics) can take place in the conjoint social-physical network. We also show, both analytically and experimentally, that the fraction of individuals who receive an item of information (started from an arbitrary node) is significantly larger in the conjoint social-physical network case, as compared to the case where the networks are disjoint. These findings reveal that conjoining the physical network with online social networks can have a dramatic impact on the speed and scale of information diffusion.
Chronic Direct Renin Inhibition With Aliskiren Prevents the Development of Hypertension in Cyp1a1-Ren2 Transgenic Rats With Inducible ANG II-Dependent Hypertension

Abstract Introduction This study was performed to determine whether chronic direct renin inhibition can prevent the development of slowly progressive angiotensin (ANG) II-dependent hypertension and the associated derangements in renal function in Cyplal-Ren2 transgenic rats with inducible expression of the Ren2 gene. Methods Male Cyplal-Ren2 rats (n = 6) were fed a normal diet containing 0.15% indole-3-carbinol (I3C) for 16 days to induce slowly progressive ANG II-dependent hypertension. Conscious systolic blood pressure was measured daily using tail-cuff plethysmography. The rats were then anesthetized with pentobarbital sodium and surgically prepared for the measurement of mean arterial pressure (MAP) and renal hemodynamics and excretory function. Results In rats induced with I3C, systolic blood pressure increased by day 3 (130 ± 7–160 ± 5 mm Hg, P 0.01) and continued to increase to 191 ± 6 mm Hg ( P 0.001) by day 16. In a separate group of rats (n = 6), chronic administration of the direct renin inhibitor, aliskiren (30 mg/kg/d, sc), prevented the development of hypertension (113 ± 5 versus 114 ± 5 mm Hg, not significant). Rats treated with aliskiren exhibited significantly lower mean arterial pressure (138 ± 4 versus 201 ± 6 mm Hg, P 0.001), renal vascular resistance (23 ± 4 versus 38 ± 3 mm Hg/mL/min · g, P 0.01), urine flow (17.6 ± 1.4 versus 25.1 ± 2.9 μ L/min, P 0.05) and urinary sodium excretion (1.11 ± 0.32 versus 2.35 ± 0.28 μ Eq/min, P 0.05) and higher renal plasma flow (4.22 ± 0.23 versus 2.56 ± 0.21 mL/min · g, P 0.01) and glomerular filtration rate (1.19 ± 0.07 versus 0.78 ± 0.08 mL/min · g, P Conclusions The present findings demonstrate that chronic direct renin inhibition with aliskiren prevents the development of ANG II-dependent hypertension and the associated derangements in renal hemodynamics and excretory function in Cyplal-Ren2 transgenic rats.
Using numerical dynamic programming to compare passive and active learning in the adaptive management of nutrients in shallow lakes.

This paper illustrates the use of dual/adaptive control methods to compare passive and active adaptive management decisions in the context of an ecosystem with a threshold effect. Using discrete-time dynamic programming techniques, we model optimal phosphorus loadings under both uncertainty about natural loadings and uncertainty regarding the critical level of phosphorus concentrations beyond which nutrient recycling begins. Active management is modeled by including the anticipated value of information (or learning) in the structure of the problem, and thus the agent can perturb the system (experiment), update beliefs, and learn about the uncertain parameter. Using this formulation, we define and value optimal experimentation both ex ante and ex post. Our simulation results show that experimentation is optimal over a large range of phosphorus concentration and belief space, though ex ante benefits are small in our example. Furthermore, realized benefits may critically depend on the true underlying parameters of the problem. Le present article illustre l'utilisation des methodes de controle adaptatif pour comparer les decisions de gestion adaptative active et passive dans le cas d'un ecosysteme ayant un effet de seuil. A l'aide des techniques de programmation dynamique en temps discret, nous avons concu un modele des charges optimales en polluants phosphores en tenant compte, a la fois, de l'incertitude quant aux charges naturelles et de l'incertitude quant au niveau critique des concentrations en phosphore au-dela desquelles le recyclage des elements nutritifs debute. Nous avons modelise la gestion active en incluant la valeur prevue de l'information (ou de l'apprentissage) dans la structure du probleme; par consequent, l'agent peut perturber le systeme (l’experience), actualiser ses croyances et decouvrir les parametres incertains. A l'aide de ce modele, nous avons caracterise et evalue l'experience optimale ex ante et ex poste. Les resultats de notre modele de simulation ont montre que l'experience est optimale pour un large eventail de concentrations en phosphore et de croyances, bien que les avantages ex ante soient faibles dans le cas de notre exemple. Les avantages realises pourraient dependre des parametres sous-jacents reels du probleme.
Sustainable Matching Plans with Adverse Selection

Economies with adverse selection are studied as matching problems. Feasible stationary matching plans are defined by market-clearing equations and informational incentive constraints. When the matching market is contestable, alternative matching systems are characterized by viable prospectus mappings. A feasible plan is sustainable if it can, with a suitably constructed waiting list, inhibit defections to all alternative matching systems. Competitively sustainable plans, which do not require centralized management of the waiting list, are shown to always exist, although they may be Pareto-dominated by other sustainable plans. Representatively sustainable plans are also defined, and are shown to always exist and be Pareto-efficient. Journal of Economic Literature Classification Numbers: C78, D82.
Voice pitch and the labor market success of male chief executive officers

Abstract A deep voice is evolutionarily advantageous for males, but does it confer benefit in competition for leadership positions? We study ecologically valid speech from 792 male public-company Chief Executive Officers (CEOs) and find that CEOs with deeper voices manage larger companies, and as a result, make more money. After including proxies for other CEO attributes including experience, education and formant position, we document economically significant voice pitch effects. For the median CEO of the median sample firm, an interquartile decrease in voice pitch (22.1Hz) is associated with a $440 million increase in the size of the firm managed, and in turn, $187 thousand more in annual compensation. Deep voiced CEOs also enjoy longer tenures. Although this is a study of association, the results are consistent with recent experimental predictions suggesting a role for voice pitch in leadership selection and also suggest economically meaningful effects of voice pitch reach the upper echelons of corporate management.
Optimal gossip with direct addressing

Gossip algorithms spread information in distributed networks by nodes repeatedly forwarding information to a few random contacts. By their very nature, gossip algorithms tend to be distributed and fault tolerant. If done right, they can also be fast and message-efficient. A common model for gossip communication is the random phone call model, in which in each synchronous round each node can PUSH or PULL information to or from a random other node. For example, Karp et al. [FOCS 2000] gave algorithms in this model that spread a message to all nodes in Θ(log n) rounds while sending only O(log log n) messages per node on average. They also showed that at least Θ(log n) rounds are necessary in this model and that algorithms achieving this round-complexity need to send ω(1) messages per node on average. Recently, Avin and Elsasser [DISC 2013], studied the random phone call model with the natural and commonly used assumption of direct addressing. Direct addressing allows nodes to directly contact nodes whose ID (e.g., IP address) was learned before. They show that in this setting, one can "break the log n barrier" and achieve a gossip algorithm running in O(√log n) rounds, albeit while using O(√log n) messages per node.In this paper we study the same model and give a simple gossip algorithm which spreads a message in only O(log log n) rounds. We furthermore prove a matching Ω(log log n) lower bound which shows that this running time is best possible. In particular we show that any gossip algorithm takes with high probability at least 0.99 log log n rounds to terminate. Lastly, our algorithm can be tweaked to send only O(1) messages per node on average with only O(log n) bits per message. Our algorithm therefore simultaneously achieves the optimal round-, message-, and bit-complexity for this setting. As all prior gossip algorithms, our algorithm is also robust against failures. In particular, if in the beginning an oblivious adversary fails any F nodes our algorithm still, with high probability, informs all but o(F) surviving nodes.
The permeation of hydrogen through the passivating films on iron and nickel

Abstract Hydrogen permeation transients for passivated iron and nickel were measured at room temperature as a function of applied anodic potential and electrolyte composition. The permeation of hydrogen through the passivated metals is controlled chiefly by the kinetic processes in the passivating films. A model describing the diffusion of hydrogen in the metal coupled with an activated jump of protons across a kinetic barrier is developed. The kinetics of hydrogen transport through passive films on iron and nickel are qualitatively discussed in terms of the specific rate parameter derived from the coupled diffusion-activated jump model fitted to the experimental curves. However, the nickel/oxide system shows inconsistencies with the model. A coupled diffusion-diffusion/migration model is proposed as an improved approach.
Can one factor the classical adjoint of a generic matrix

Let k be an integral domain, n a positive integer, X a generic n × n matrix over k (i.e., the matrix (xij over a polynomial ring k[xij] in n2 indeterminates xij), and adj(X) its classical adjoint. For char k = 0, it is shown that if n is odd, adj(X) is not the product of two noninvertible n × n matrices over k[xij], while for n even, only one special sort of factorization occurs. Whether the corresponding results hold in positive characteristic is not known. The operation adj on matrices arises from the (n – 1)st exterior power functor on modules; the analogous factorization question for matrix constructions arising from other functors is raised, as are several other questions.
Properties of photorefractive gratings with complex coupling constants

We examine simultaneous write–read of dynamic photorefractive gratings for arbitrary phase shifts between index grating and intensity pattern. The nonlinear behavior of diffraction efficiency with read beam intensity, as well as the nonreciprocity of diffraction efficiency with respect to direction of readout, is examined for various values of the phase shift.
DEVELOPMENT AND THE IMPACT OF CLIMATE CHANGE ON ENERGY DEMAND: EVIDENCE FROM BRAZIL

This paper investigates the effects of climate on residential electricity use for households from different income classes in Brazil. Using cross-sectional data, the study finds that the temperature elasticity of electricity consumption varies significantly across income classes. The temperature elasticity of low income households is not significantly different from zero but middle and high income families have a long run temperature elasticity of 0.8 and 1.6 respectively. As emerging low latitude countries develop and incomes rise, the welfare damages of warming in the energy sector will become substantial.
Sampling-based temporal logic path planning

In this paper, we propose a sampling-based motion planning algorithm that finds an infinite path satisfying a Linear Temporal Logic (LTL) formula over a set of properties satisfied by some regions in a given environment. The algorithm has three main features. First, it is incremental, in the sense that the procedure for finding a satisfying path at each iteration scales only with the number of new samples generated at that iteration. Second, the underlying graph is sparse, which guarantees the low complexity of the overall method. Third, it is probabilistically complete. Examples illustrating the usefulness and the performance of the method are included.
When deal depth doesn't matter: How handedness consistency influences consumer response to horizontal versus vertical price comparisons

The current research introduces a new moderator to the price comparison literature by considering how the processing of regular and sale price information may be grounded in the degree to which consumers are consistent-handed (CHs) or inconsistent-handed (ICHs) in performing manual tasks. Because vertically presenting regular and sale price information facilitates calculation of savings, vertical price comparisons should be processed more fluently than horizontal comparisons. However, this fluency difference should asymmetrically affect ICHs and CHs. Prior research has indicated that ICHs are more cognitively flexible than CHs. Here, ICHs expressed more favorable purchase intentions with greater deal depth for both vertical and horizontal price comparisons, possibly because their greater cognitive flexibility enabled them to process price comparisons effectively regardless of presentation layout. Conversely, possibly due to lower cognitive flexibility, CHs exhibited purchase intentions that were sensitive to differences in deal depth when presented with more fluent vertical price comparisons, but not less fluent horizontal comparisons. These findings are replicated across two experiments relying on different participant populations.
Glance: A lightweight querying service for wireless sensor networks

Distance-sensitivity guarantee in querying is a highly desirable property in wireless sensor networks as it limits the cost of executing a ''query'' operation to be within a constant factor of the distance to the nearest node that contains an answer. However, such a tight guarantee may require building an infrastructure for efficient resolution of queries, and the cost of maintaining this infrastructure may be prohibitive. Here we show that it is possible to implement distance-sensitive querying in an efficient way by exploiting the geometry of the network. Our querying service Glance ensures that a ''query'' operation invoked within d distance of an event intercepts the event's ''advertise'' operation within d*s distance, where s is a ''stretch-factor'' tunable by the user.
XMM-Newton Observations of the Galactic Supernova Remnant CTB 109 (G109.1–1.0)

We present the analysis of the X-ray Multimirror Mission (XMM-Newton) European Photon Imaging Camera (EPIC) data of the Galactic supernova remnant (SNR) CTB 109 (G109.1-1.0). CTB 109 is associated with the anomalous X-ray pulsar (AXP) 1E 2259+586 and has an unusual semicircular morphology in both the X-ray and the radio and an extended X-ray bright interior region known as the "Lobe." The deep EPIC mosaic image of the remnant shows no emission toward the west where a giant molecular cloud complex is located. No morphological connection between the Lobe and the AXP is found. We find remarkably little spectral variation across the remnant given the large intensity variations. All spectra of the shell and the Lobe are well fitted by a single-temperature nonequilibrium ionization model for a collisional plasma with solar abundances [kT ≈ 0.5-0.7 keV, τ = ne dt ≈ (1-4) × 1011 s cm-3, NH ≈ (5-7) × 1021 cm-2]. There is no indication of nonthermal emission in the Lobe or the shell. We conclude that the Lobe originated from an interaction of the SNR shock wave with an interstellar cloud. Applying the Sedov solution for the undisturbed eastern part of the SNR and assuming full equilibration between the electrons and ions behind the shock front, the SNR shock velocity is derived as vs = 720 ± 60 km s-1, the remnant age as t = (8.8 ± 0.9) × 103d3 yr, the initial energy as E0 = (7.4 ± 2.9) × 1050d ergs, and the preshock density of the nuclei in the ambient medium as n0 = (0.16 ± 0.02)d cm-3, at an assumed distance of D = 3.0d3 kpc. Assuming that CTB 109 and 1E 2259+586 are associated, these values constrain the age and the environment of the progenitor of the SNR and the pulsar.
CHEMICAL MECHANISMS OF CATALYTIC CRACKING OVER SOLID ACIDIC CATALYSTS: ALKANES AND ALKENES

The review discusses chemical mechanisms of most important reactions that take place in the course of catalytic cracking of alkenes and alkanes over solid acidic catalysts. The main subject of the review is the mechanism of the principal cracking step, fission of C─C bonds in aliphatic hydrocarbons. The cracking mechanism of alkenes via carbenium ion intermediates (with complications caused by oligomerization reactions) is well established. In contrast, the C─C bond fission mechanism in alkanes is still a controversial subject. The review compares merits and difficulties of different mechanisms proposed in the literature: several carbenium-ion mechanisms, the carbonium-ion mechanism, the chain-reactions mechanism with participation of both carbonium and carbenium ions, and the oxonium-ion mechanism. Reactions accompanying C─C-bond fission in cracking reactions, hydrogen redistribution, formation of cycloalkanes, light aromatic compounds, and coke are also briefly discussed.
Understanding boron through size-selected clusters: structure, chemical bonding, and fluxionality.

ConspectusBoron is an interesting element with unusual polymorphism. While three-dimensional (3D) structural motifs are prevalent in bulk boron, atomic boron clusters are found to have planar or quasi-planar structures, stabilized by localized two-center–two-electron (2c–2e) σ bonds on the periphery and delocalized multicenter–two-electron (nc–2e) bonds in both σ and π frameworks. Electron delocalization is a result of boron’s electron deficiency and leads to fluxional behavior, which has been observed in B13+ and B19–. A unique capability of the in-plane rotation of the inner atoms against the periphery of the cluster in a chosen direction by employing circularly polarized infrared radiation has been suggested. Such fluxional behaviors in boron clusters are interesting and have been proposed as molecular Wankel motors. The concepts of aromaticity and antiaromaticity have been extended beyond organic chemistry to planar boron clusters. The validity of these concepts in understanding the electronic structu...
Propagation of Raman-matched laser pulses through a Bose–Einstein condensate

Abstract We investigate the role of non-uniform spatial density profiles of trapped atomic Bose–Einstein condensates in the propagation of Raman-matched laser pulses under conditions for electromagnetically induced transparency (EIT). We find that the sharp edged axial density profile of an interacting condensate (due to a balance between external trap and repulsive atomic interaction) is advantageous for obtaining ultraslow averaged group velocities. Our results are in good quantitative agreement with a recent experiment report [Nature 397 (1999) 594].
On Regularity for Measures in Multiplicative Free Convolution Semigroups

Given a probability measure μ on the real line, there exists a semigroup μ t with real parameter t > 1 which interpolates the discrete semigroup of measures μ n obtained by iterating its free convolution. It was shown in (Math. Z. 248(4):665–674, 2004) that it is impossible that μ t have no mass in an interval whose endpoints are atoms. We extend this result to semigroups related to multiplicative free convolution. The proofs use subordination results.
Interference Alignment and the Generalized Degrees of Freedom of the $X$ Channel

We explore the capacity and generalized degrees of freedom (GDOF) of the two-user Gaussian X channel, i.e., a generalization of the two-user interference channel where there is an independent message from each transmitter to each receiver. There are three main results in this paper. First, we characterize the sum capacity of the deterministic X channel under a symmetric setting. Second, we characterize the GDOF of the Gaussian X channel under a similar symmetric model. Third. we extend the sum capacity characterization previously obtained for the Gaussian interference channel in the noisy interference regime to the Gaussian X channel. Specifically, we show that the Gaussian X channel has the same sum capacity as the underlying Gaussian interference channel in this regime.
Infrared Emission from Interstellar Dust. II. The Diffuse Interstellar Medium

We present a quantitative model for the infrared emission from dust in the diffuse interstellar medium. The model consists of a mixture of amorphous silicate grains and carbonaceous grains, each with a wide size distribution ranging from molecules containing tens of atoms to large grains 1 μm in diameter. We assume that the carbonaceous grains have properties like polycyclic aromatic hydrocarbons (PAHs) at very small sizes and graphitic properties for radii a 50 A. On the basis of recent laboratory studies and guided by astronomical observations, we propose astronomical absorption cross sections for use in modeling neutral and ionized PAHs from the far-ultraviolet to the far-infrared. We also propose modifications to the far-infrared emissivity of astronomical silicate. We calculate energy distribution functions for small grains undergoing temperature spikes caused by stochastic absorption of starlight photons using realistic heat capacities and optical properties. Using a grain-size distribution consistent with the observed interstellar extinction, we are able to reproduce the near-IR to submillimeter emission spectrum of the diffuse interstellar medium, including the PAH emission features at 3.3, 6.2, 7.7, 8.6, and 11.3 μm. The model is compared with the observed emission at high Galactic latitudes as well as in the Galactic plane, as measured by the COBE/DIRBE, COBE/FIRAS, IRTS/MIRS, and IRTS/NIRS instruments. The model has 60 × 10-6 of C (relative to H) locked up in PAHs, with 45 × 10-6 of C in a component peaking at ~6 A (NC ≈ 100 carbon atoms) to account for the PAH emission features and with 15 × 10-6 of C in a component peaking at ~50 A to account for the 60 μm flux. The total infrared emission is in excellent agreement with COBE/DIRBE observations at high Galactic latitudes, just as the albedo for our grain model is in accord with observations of the diffuse Galactic light. The aromatic absorption features at 3.3 and 6.2 μm predicted by our dust model are consistent with observations. We calculate infrared emission spectra for our dust model heated by a range of starlight intensities, from 0.3 to 104 times the local interstellar radiation field, and we tabulate the intensities integrated over the SIRTF/IRAC and MIPS bands. We also provide dust opacities tabulated from the extreme-ultraviolet to submillimeter wavelengths.
Imaging of director fields in liquid crystals using stimulated Raman scattering microscopy

We demonstrate an approach for background-free three-dimensional imaging of director fields in liquid crystals using stimulated Raman scattering microscopy. This imaging technique is implemented using a single femtosecond pulsed laser and a photonic crystal fiber, providing Stokes and pump frequencies needed to access Raman shifts of different chemical bonds of molecules and allowing for chemically selective and broadband imaging of both pristine liquid crystals and composite materials. Using examples of model three-dimensional structures of director fields, we show that the described technique is a powerful tool for mapping of long-range molecular orientation patterns in soft matter via polarized chemical-selective imaging.
Hydrostatic Stress Effect on the Yield Behavior of Inconel 100

Classical metal plasticity theory assumes that hydrostatic stress has no effect on the yield and postyield behavior of metals. Recent reexaminations of classical theory have revealed a significant effect of hydrostatic stress on the yield behavior of notched geometries. New experiments and nonlinear finite element analyses (FEA) of Inconel 100 (IN 100) equal-arm bend and double-edge notch tension (DENT) test specimens have revealed the effect of internal hydrostatic tensile stresses on yielding. Nonlinear FEA using the von Mises (yielding is independent of hydrostatic stress) and the Drucker-Prager (yielding is linearly dependent on hydrostatic stress) yield functions was performed. In all test cases, the von Mises constitutive model, which is independent of hydrostatic pressure, overestimated the load for a given displacement or strain. Considering the failure displacements or strains, the Drucker-Prager FEMs predicted loads that were 3% to 5% lower than the von Mises values. For the failure loads, the Drucker Prager FEMs predicted strains that were 20% to 35% greater than the von Mises values. The Drucker-Prager yield function seems to more accurately predict the overall specimen response of geometries with significant internal hydrostatic stress influence.
Protamine sulfate enhances lipid-mediated gene transfer

A polycationic peptide, protamine sulfate, USP, has been shown to be able to condense plasmid DNA efficiently for delivery into several different types of cells in vitro by several different types of cationic liposomes. The monovalent cationic liposomal formulations (DC-Chol and lipofectin) exhibited increased transfection activities comparable to that seen with the multivalent cationic liposome formulation, lipofectamine. This suggests that lipofectamine’s superior in vitro activity arises from its ability to condense DNA efficiently and that protamine’s primary role is that of a condensation agent, although it also possesses several amino acid sequences resembling that of a nuclear localization signal. While the use of polycations to condense DNA has been previously reported, the use of protamine sulfate, USP as a condensation agent was found to be superior to poly- L-lysine as well as to various other types of protamine. These differences among various salt forms of protamine appear to be attributable to structural differences between the protamines and not due to differences in the net charge of the molecule. The appearance of lysine residues within the protamine molecule correlate with a reduction in binding affinity to plasmid DNA, as well as an observed loss in transfection-enhancing activity. This finding sheds light on the structural requirements of condensation agents for use in gene transfer protocols. Furthermore, protamine sulfate, USP is an FDA-approved compound with a documented safety profile and could be readily used as an adjuvant to a human gene therapy protocol.
Template-directed synthesis employing reversible imine bond formation

The imine bond – formed by the reversible condensation of an amine and an aldehyde – and its applications as a dynamic covalent bond in the template-directed synthesis of molecular compounds, will be the focus of this tutorial review. Template-directed synthesis – or expressed another way, supramolecular assistance to covalent synthesis – relies on the use of reversible noncovalent bonding interactions between molecular building blocks in order to preorganise them into a certain relative geometry as a prelude to covalent bond formation to afford the thermodynamically preferred product. The use of this so-called dynamic covalent chemistry (DCC) in templated reactions allows for an additional amount of reversibility, further eliminating potential kinetic products by allowing the covalent bonds that are formed during the template-directed reaction to be ‘proofread for errors’, thus making it possible for the reaction to search out its thermodynamic minimum. The marriage of template-directed synthesis with DCC has allowed chemists to construct an increasingly complex collection of compounds from relatively simple precursors. This new paradigm in organic synthesis requires that each individual piece in the molecular self-assembly process is preprogrammed so that the multiple recognition events expressed between the pieces are optimised in a highly cooperative manner in the desired product. It offers an extremely simple way of making complex mechanically interlocked compounds – e.g., catenanes, rotaxanes, suitanes, Borromean rings and Solomon knots – from relatively simple precursors.
Gamma-ray burst positions from the ASM on RXTE

The RXTE/ASM has detected and positioned 14 confirmed GRB bursts (at this writing, Jan. 1999) including six whose positions were communicated to the community 2 to 32 hours after the burst. Two of these latter bursts led to measurements of optical red shifts but one, despite an easily detected X-ray afterglow, produced no detectable optical or radio afterglow.
Comparison of Jupiter interior models derived from first-principles simulations

Recently two groups used first-principles computer simulations to model Jupiter’s interior. While both studies relied on the same simulation technique, density functional molecular dynamics, the groups derived very different conclusions. In particular estimates for the size of Jupiter’s core and the metallicity of its hydrogen-helium mantle differed substantially. In this paper, we discuss the differences of the approaches and give an explanation for the differing conclusions.
The J-Shape of Performance Persistence Given Survivorship Bias

Performance may enhance survival probability. When it does, the induced lack of randomness challenges robust and unbiased inference. If survivors are sorted into two groups based on past performance, spurious persistence has been demonstrated if variance in performance is heterogeneous. However, as we show both theoretically and with simulations, if performance is categorized finely, the spurious persistence will be J-shaped; that is, at the bottom better performance in one period “predicts” worse performance for another period. We propose a simple t-test applied to the quadratic coefficient in a regression to distinguish between a spurious J-shape and monotonic patterns. Mutual funds, our example, exhibit the monotonically increasing pattern produced by true performance persistence.
Intramolecular ene reaction of a chiral bicyclic lactam.

The preparation of bicylic lactam 2 is described, employing an acetoacetate-based synthesis of 1,4-ketoacid 3. The lactam 2 was shown to undergo a thermal ene reaction at 280−300 °C to afford tricycle 7. Reduction of the ene product followed by removal of the chiral auxiliary fragment provided the unusual lactam system 9 in highly enantioenriched form.
Excited states and gas phase photofragmentation of palladium and platinum hexafluoroacetylacetonates

Abstract The properties of excited electronic states of acetylacetonate complexes of palladium and platinum, and the photochemical reactivities of the fluorinated derivatives in the gas phase are reviewed. These complexes are precursors for the thermal and photochemical production of metal films via metal organic chemical vapor deposition. This review is organized in three sections. First, the electronic structure is surveyed, the results of molecular orbital calculations are discussed, and the theoretical results are compared with the electronic spectra. Second, gas phase spectroscopy is discussed. Both electronic absorption spectra of hot gases and excitation spectra in a molecular beam have been used to assign the lowest excited states. Finally, the gas phase photochemistry is discussed. Solid photoproducts including particles and films are briefly reviewed, and photoproducts in the gas (identified by emission and time of flight mass spectroscopy) are discussed. The relevance of the gas phase photochemistry to laser assisted chemical vapor deposition is emphasized.
Reactions of metallocarbenes derived from N-sulfonyl-1,2,3-triazoles

Metal-stabilized carbenes derived from diazo compounds have become broadly useful reactive intermediates for organic synthesis. This tutorial review will describe the recent advances in using N-sulfonyl-1,2,3-triazoles as precursors for the formation of metal-bound imino carbene intermediates. These intermediates undergo a variety of synthetically useful transformations, which include transannulation reactions to generate new heterocycles, cyclopropanation and subsequent ring expansions, ylide formation with subsequent rearrangements, and C–H functionalization. Furthermore, many of these transformations can be conducted with high levels of enantioselectivity by use of chiral rhodium(II) catalysts.
Short and efficient chiral pool and RCM approach towards the synthesis of the macrocyclic core of the salicylihalamides

The macrolactone core structure of the salicylihalamides was prepared from diacetone-D-glucose and via a ring-closing metathesis reaction.
Wellbore flow model for carbon dioxide and brine

Abstract Wellbores have been identified as the most likely conduit for CO 2 and brine leakage from geologic carbon sequestration (GCS) sites, especially those in sedimentary basins with historical hydrocarbon production. In order to quantify the impacts of leakage of CO 2 and brine through wellbores, we have developed a wellbore simulator capable of describing non-isothermal open-well flow dynamics of CO 2 -brine mixtures. The mass and thermal energy balance equations are solved numerically by a finite difference scheme with wellbore heat transmission handled semi-analytically. This new wellbore simulator can take as input the pressure, saturation, and composition conditions from reservoir simulators and calculate CO 2 and brine fluxes needed to assess impacts to vulnerable resources. This new capability is being incorporated into the Certification Framework (CF) developed for risk assessment of GCS sites.
Systematic decision process for intelligent decision making

In this paper, Systematic decision process (SDP) for solving Multiple Criteria Decision Making problems with application for manufacturing location selection is introduced. SDP is a comprehensive approach which is based on eliciting strength of preferences for assessing additive utility functions. SDP consists of three steps: I. assessing weights, II. assessing qualitative criteria, and III. ranking alternatives using the assessed additive utility function. Strengths of preferences can be expressed by using either qualitative or numerical ratings. If the decision maker is inconsistent in his/her responses, such inconsistencies are identified by the method. It is shown that the method has advantages in terms of simplicity and accuracy compared to existing methods such as Analytical Hierarchy Process. Furthermore, a quadratic optimization method for assessing weights of additive utility function by use of pair comparison of actual alternatives is developed. Computational experiments are provided.
Temporal evolution of three-dimensional vortex breakdown from steady, axisymmetric solutions

HE emergence and consequences of asymmetries in swirling flows that are initially steady and axisymmetric are examined. The strength of an isolated vortex in a tube is increased in a parametric fashion through a critical value, where stability to three-dimensional disturbances is lost. The flow behavior undergoes a bifurcation at the critical value from steady and axisymmetric flow to unsteady and three-dimensional flow. Other computations of bifurcation phenomena in swirling flows have been presented by Leibovich and Kribus,1 Reran and Culick,2 and Lopez.3 These works are limited to bifurcations that only involve axisymmetric flows. Axisymmetric base flows serve as initial conditions to a threedimensional time-integration algorithm. The minimum axial velocity component Q (t) is computed and compared with the initial value. Of particular interest is the characterization of the stability loss and the relationship between the appearance of asymmetries and the associated changes in Q. The computational approach is as follows. First, a pseudoarclength continuation (PAC) algorithm2 provides the steady, axisymmetric initial condition for a specified vortex strength V. The Mach number M and Reynolds number Re (based on vortex core radius) are held fixed at 0.3 and 2.5 x 102, respectively. No nonunique axisymmetric solutions are found at Re — 2.5 x 10 2, consistent with Ref. 2. The two-dimensional solution is then interpolated onto the three-dimensional mesh using a fourth-order-accurate cubic spline scheme.4 Then time integration is carried out by the time-accurate Navier-Stokes (TANS) model. The TANS model is a special-purpose, time-integration algorithm developed specifically for this work and is described in Ref. 5. The TANS model employs fourth-order compact, or Fade, operators6 to discretize spatial derivatives, thus allowing for fewer grid nodes while maintaining sufficient accuracy. A multiblock grid is used to allow for a nearly rectilinear arrangement of nodes near the tube centerline, while near orthogonality is maintained at the tube wall. The PAC algorithm is implemented with the same boundary conditions and tube geometry as the TANS model, using a simple algebraic grid. The physical domain consists of a two-stage cylindrical tube of circular cross section and varying radius.2 The first stage contains a constriction that controls the upstream movement of the breakdown region. The tube radius (nondimensionalized by vortex core radius) at the inlet station is fixed at /? 0 = 2. The number of nodes in the computational coordinate directions are (nx, ny, nz), where nx defines stream wise spacing and ny and nz are equal and define cross-plane spacing in the y and z directions, respectively. Three grids are employed in this work. Grid Gl consists of 98 x 41 2 nodes, grid G2 contains 122 x 612 nodes, and grid G3 uses 146 x 412
Entanglement entropy and the Fermi surface.

Free fermions with a finite Fermi surface are known to exhibit an anomalously large entanglement entropy. The leading contribution to the entanglement entropy of a region of linear size $L$ in $d$ spatial dimensions is $S\ensuremath{\sim}{L}^{d\ensuremath{-}1}\mathrm{log}﻿L$, a result that should be contrasted with the usual boundary law $S\ensuremath{\sim}{L}^{d\ensuremath{-}1}$. This term depends only on the geometry of the Fermi surface and on the boundary of the region in question. I give an intuitive account of this anomalous scaling based on a low energy description of the Fermi surface as a collection of one-dimensional gapless modes. Using this picture, I predict a violation of the boundary law in a number of other strongly correlated systems.
Sums and products with smooth numbers

Abstract We estimate the sizes of the sumset A + A and the productset A ⋅ A in the special case that A = S ( x , y ) , the set of positive integers n ⩽ x free of prime factors exceeding y .
Phagocytic signaling molecules in lipid rafts of COS-1 cells transfected with FcγRIIA

Abstract COS-1 cells bearing FcγRIIA were used as a model to demonstrate co-localization of several enzymes previously shown to regulate neutrophil phagocytosis. In COS-1 cells, phospholipase D (PLD) in the membrane fraction was activated during phagocytosis. PLD was found almost exclusively in lipid rafts, along with RhoA and ARF1. Protein kinase C-δ (PKCδ) and Raf-1 translocated to lipid rafts. In neutrophils, ceramide levels increase during phagocytosis, indicating that FcγRIIA engagement initiates ceramide generation. Applying this model, we transfected COS-1 cells with FcγRIIA that had been mutated in the ITAM region, rendering them unable to ingest particles. When the mutant receptors were engaged, ceramide was generated and MAPK was activated normally, thus these processes did not require actual ingestion of particles. These results indicate that signaling proteins for phagocytosis are either constitutively present in, or are recruited to, lipid rafts where they are readily available to activate one another.
Channel state feedback over the MIMO-MAC

We consider the problem of designing low latency and low complexity schemes for channel state feedback over the MIMO-MAC (multiple-input multiple-output multiple access channel). We develop a framework for analyzing this problem in terms of minimizing the distortion, and come up with separated source-channel schemes and joint source-channel schemes that perform better than traditional analog feedback. The results are validated through simulations using very simple channel codes.
Characters of Connected Lie Groups

Unitary representations of locally algebraic groups Unitary representations of elementary groups Existence of characters Generalized Kirillov theory Bibliography.
Articulated Hands: Force Control and Kinematic Issues

Kinematic and control issues are discussed in the context of an articulated, multifinger mechanical hand. Hand designs with particular mobility properties are illustrated, and a definition of accuracy points within manipulator workspace is given. Optimization of tlte physical dimensions of the Stanford-JPL hand is described. Several architectures for position and force control of this multiloop mechanism are described, including a way of dealing with the internal forces inherent in such systems. Preliminary results are shown for the joint torque subsystem used in the hand controller.
Time-frequency analysis of crude oil and S&P500 futures contracts

We use frequency-domain techniques, namely wavelets and cross-spectra, to examine the association between the daily prices of crude oil futures and daily S&P500 futures closing prices over the past several decades. We investigate contemporaneous and lag–lead relationships in levels and returns. It is our belief that the wavelet and cross-spectral analyses employed in this paper offer insights regarding the relationship between oil prices and stock returns that are not apparent from a conventional time-domain framework. Our findings cast doubt on the purported negative relationship between oil and the U.S. stock market. Our analysis suggests that oil prices lead oil volume, and S&P500 trading volume leads S&P500 prices.
Introduction to the Mathematical and Statistical Foundations of Econometrics

This book is intended for use in a rigorous introductory PhD level course in econometrics, or in a field course in econometric theory. It covers the measure-theoretical foundation of probability theory, the multivariate normal distribution with its application to classical linear regression analysis, various laws of large numbers, central limit theorems and related results for independent random variables as well as for stationary time series, with applications to asymptotic inference of M-estimators, and maximum likelihood theory. Some chapters have their own appendices containing the more advanced topics and/or difficult proofs. Moreover, there are three appendices with material that is supposed to be known. Appendix I contains a comprehensive review of linear algebra, including all the proofs. Appendix II reviews a variety of mathematical topics and concepts that are used throughout the main text, and Appendix III reviews complex analysis. Therefore, this book is uniquely self-contained.
Transverse instability of solitons propagating on current-carrying metal thin films

Abstract Small amplitude, long waves traveling over the surface of a current-carrying metal thin film are studied. The equation of motion for the metal surface is determined in the limit of high applied currents, when surface electromigration is the predominant cause of adatom motion. If the surface height h is independent of the transverse coordinate y, the equation of motion reduces to the Korteweg–de Vries equation. One-dimensional solitons (i.e., those with h independent of y) are shown to be unstable against perturbations to their shape with small transverse wavevector.
Momentum Trading: The New Alchemy

Momentum traders buy stock (often on margin) as prices rise and sell as prices fall. In essence, they are trying to obtain the benefits of a call option--upside participation with limited risk on the downside--without any payment of an option premium. The strategy appears to offer a chance of huge gains with little risk and minimal cost, but its real risks and costs become known only when it9s too late--after the strategy has failed, and taken markets down with it.