cssi/SciSciGPT-SciSciNet huggingface dataset:
GCN2-like eIF2α kinase manages the amino acid starvation response in Toxoplasma gondii.

The apicomplexan protozoan Toxoplasma gondii is a significant human and veterinary pathogen. As an obligate intracellular parasite, Toxoplasma depends on nutrients provided by the host cell and needs to adapt to limitations in available resources. In mammalian cells, translational regulation via GCN2 phosphorylation of the alpha subunit of eukaryotic translation initiation factor 2 (eIF2α) is a key mechanism for adapting to nutrient stress. Toxoplasma encodes two GCN2-like protein kinases, TgIF2K-C and TgIF2K-D. We previously showed that TgIF2K-D phosphorylates T. gondii eIF2α (TgIF2α) upon egress from the host cell, which enables the parasite to overcome exposure to the extracellular environment. However, the function of TgIF2K-C remained unresolved. To determine the functions of TgIF2K-C in the parasite, we cloned the cDNA encoding TgIF2K-C and generated knockout parasites of this TgIF2α kinase to study its function during the lytic cycle. The TgIF2K-C knockout did not exhibit a fitness defect compared with parental parasites. However, upon infection of human fibroblasts that were subsequently cultured in glutamine-free medium, the intracellular TgIF2K-C knockout parasites were impeded for induced phosphorylation of TgIF2α and showed a 50% reduction in the number of plaques formed compared with parental parasites. Furthermore, we found that this growth defect in glutamine-free media was phenocopied in parasites expressing only a non-phosphorylatable TgIF2α (TgIF2α-S71A), but not in a TgIF2K-D knockout. These studies suggest that Toxoplasma GCN2-like kinases TgIF2K-C and TgIF2K-D evolved to have distinct roles in adapting to changes in the parasite’s environment.
Quarks in the universe

Matter in its present form was formed when our Universe emerged from the quark-gluon phase (QGP) at about 30mus into its evolution. To explore this early period in the laboratory, we study highly excited matter formed in relativistic heavy ion collision experiments: heavy nuclei crash into each other, and form compressed and energetically excited nuclear matter, resembling in its key features the stuff which filled the early Universe. In these experiments we further explore the physics of the vacuum structure of strongly interacting gauge theory, Quantum Chromodynamics (QCD). The common beginning for both, heavy ion collisions, and vacuum structure investigations, is the physics of the quantum electrodynamic (QED) vacuum in the presence of the supercritical external field that is formed when two highly charged heavy ions are brought together near to the Coulomb barrier in a considerably lower reaction energy collision.
Analogies to oceanic behaviour in the continental breakup of the western Woodlark basin

THE Woodlark basin/D'Entrecasteaux Island region off northeast Papua New Guinea (Fig. 1) offers a rare glimpse of the propagation of active rifting and continental breakup1 into orogenically thickened (and subsequently extended) lithosphere2–10. Rifting, continental breakup, and the subsequent formation of oceanic lithosphere by sea-floor spreading often involve rupture controlled by propagation of a rift tip11–20. We recognize several tectonic elements in the evolving western Woodlark intracontinental system that are close geometric analogues of wholly oceanic propagators, and a kinematic development that can be viewed as an extrapolation of oceanic tectonics. The response to deformational stresses in the final stages of breakup in a thick, relatively hot, and hence weak continental lithosphere appears akin to that of oceanic lithosphere.
The Medial axis of a union of balls

Abstract We present an algorithm for computing the exact interior medial axis of a union of balls in R d . Our algorithm combines the simple characterization of this medial axis given by Attali and Montanvert with the combinatorial information provided by Edelsbrunner's α-shape. This leads to a simple algorithm, which we have implemented for d=3.
Fe(III)/NaBH4-Mediated Free Radical Hydrofluorination of Unactivated Alkenes

A powerful Fe(III)/NaBH4-mediated free radical hydrofluorination of unactivated alkenes is disclosed using Selectfluor reagent as a source of fluorine and resulting in exclusive Markovnikov addition. In contrast to the traditional and unmanageable free radical hydrofluorination of alkenes, the Fe(III)/NaBH4-mediated reaction is conducted under exceptionally mild reaction conditions (0 °C, 5 min, CH3CN/H2O). The reaction can be conducted open to the air and with water as a cosolvent and demonstrates an outstanding substrate scope and functional group tolerance.
Catalytic formation of cyclic-esters and -depsipeptides and chemical amplification by complexation with sodium ions

Abstract Lactide, LA, reacts in benzene solution at ∼70 °C with a polystyrene supported lithium alkoxide catalyst to release cycles (CHMeC(O)O) n to the solution by ring-opening polymerization and intra-chain trans -esterification. Polylactide, PLA, similarly reacts to yield cycles (CHMeC(O)O) n . The cycles back-react with the supported catalyst and with time form a dynamic combinatorial library of rings from which the 18-membered rings (CHMeC(O)O) 6 are selectively removed by complexation with NaBPh 4 . In this way LA may be converted to (CHMeC(O)O) 6 in ∼80% yield based on NaBPh 4 . Similar reactions occur for 3,6-substituted-1,4-dioxane-2,5-diones and 2,5-morpholine diones. These reactions occur with epimerization of the methine carbon stereocenter. In reactions involving 4 equiv. of LA or glycolide and NaBPh 4 , 4-dimethylaminopyridine in heated benzene the 18-membered cyclic esters form 1:1 adducts with NaBPh 4 . The structures of several of the isomers of (CHMeC(O)O) 6 are reported together with complexes with NaBPh 4 . The NMR spectra for the two meso isomers and the six enantiomers are reported. Similar complexation of (CH 2 C(O)O) 6 , derived from glycolide, to Na + is described along with its free unligated structure.
Design of magnetic bearings for rotor systems with harmonic excitations

This paper presents a method for calcutating the control forces and the bearing stiffness and damping coefficients to control the response of multi mass flexible rotor systems mounted on magnetic bearings and subjected to unbalance or harmonic excitation forces. The capability for inclusion of hydrodynamic bearings is retained to model seal efects or to permit the design of magnetic bearings for hybrid systems
High efficiency single photon detection via frequency up-conversion

Abstract We propose a method of single photon detection of infrared (IR) photons at potentially higher efficiencies and lower noise than allowed by traditional IR band avalanche photodiodes (APDs). By up-converting the photon from the IR, e.g. 1550 nm, to a visible wavelength in a nonlinear crystal, we can utilize the much higher efficiency of silicon APDs at these wavelengths. We have used a periodically poled lithium niobate (PPLN) crystal and a pulsed 1064 nm Nd:YAG laser to perform the up-conversion to a 631 nm photon. We observed conversion efficiencies as high as ∼ 80%, and demonstrated scaling down to the single photon level while maintaining a background of 3 ×s; 10−4 dark counts per count. We also propose a 2-crystal extension of this scheme, whereby orthogonal polarizations may be up-converted coherently, thus enabling complete quantum state transduction of arbitrary states.
Palladium-catalyzed coupling of ammonia and lithium amide with aryl halides.

A mild, palladium-catalyzed coupling of aryl halides with ammonia or lithium amide to form primary arylamines as the major product is described. These reactions occurred with excellent selectivity for formation of the primary arylamine over formation of the diarylamine (9.5:1 to over 50:1 ratios of arylamine to diarylamine). In addition, the first organopalladium complex with a terminal −NH2 ligand has been isolated. This complex reductively eliminates to form arylamines.
Intrinsic curvature determines the crinkled edges of “crenellated disks”

Elastic curvature constants determine many structural and functional properties of fluid membranes. Methods to measure the mean curvature modulus have proved to be robust. In contrast, Gaussian curvature is an intrinsic property of a surface. Thus, measuring the relevant modulus in fluid membranes remains a challenging task. Inspired from colloidal “crenellated disks” observed in a model system composed of hard rods, we propose a concise relation between the two curvature moduli and the parameters associated with the free, crinkled edges. Our approach offers a straightforward way to determine of these reconfigurable membranes, where various complex topologies can be nanosculpted. Further, we reveal the structure and stability of the “crenellated disks.”
Design of radiant enclosures using inverse and non-linear programming techniques

Traditionally, radiant enclosures have been designed using a forward “trial-and-error” methodology. Recently, however, inverse and optimization methodologies have been applied to design radiant enclosures. Both of these methodologies solve the design problem faster, and the quality of the solutions is usually better than those obtained through the forward design methodology. This article presents forward, inverse, and optimization formulations of the infinitesimal-area method that can be used to solve design problems involving radiant enclosures. The inverse and optimization methodologies are then demonstrated and compared by using them to design a 2-D radiant enclosure containing a transparent medium.
Aerosol synthesis and Rietveld analysis of tetragonal (β1) PdZn

The {beta}{sub 1} PdZn intermetallic of nominal 50:50 Pd:Zn at% was synthesized using an aerosol method. The aerosol method provided atomically mixed precursor oxy-nitrate powder that was then reduced to form {beta}{sub 1} PdZn, having a surface area amenable to catalytic measurements. Formation of the {beta}{sub 1} PdZn during reduction was found to occur rapidly (4 h) and at moderate temperature (500 C), serving to minimize the loss of volatile Zn. Chemical and structural characterization confirms that {beta}{sub 1} PdZn (95-99 wt% phase pure) of the same composition as the nitrate feedstock solution can be prepared using this method. Detailed structural analysis shows that this material contains little or no vacancies and minimal Pd/Zn disorder.
Multiple Antenna Cyclostationary Spectrum Sensing Based on the Cyclic Correlation Significance Test

In this paper, we propose and analyze a spectrum sensing method based on cyclostationarity specifically targeted for receivers with multiple antennas. This detection method is used for determining the presence or absence of primary users in cognitive radio networks based on the eigenvalues of the cyclic covariance matrix of received signals. In particular, the cyclic correlation significance test is used to detect a specific signal-of-interest by exploiting knowledge of its cyclic frequencies. Analytical asymptotic expressions for the probability of detection and probability of false-alarm under both spatially uncorrelated and spatially correlated noise are derived and verified by simulations. The detection performance in a Rayleigh flat-fading environment is found and verified through simulations. One of the advantages of the proposed method is that the detection threshold is shown to be independent of both the number of samples and the noise covariance, effectively eliminating the dependence on accurate noise estimation. The proposed method is also shown to provide higher detection probability and better robustness to noise uncertainty than existing multiple antenna cyclostationary-based spectrum sensing algorithms under both AWGN as well as a quasi-static Rayleigh fading channel.
Foldy–Wouthuysen transformation, scalar potentials and gravity

We show that care is required in formulating the nonrelativistic limit of generalized Dirac Hamiltonians which describe particles and antiparticles interacting with static electric and/or gravitational fields. The Dirac–Coulomb and the Dirac–Schwarzschild Hamiltonians, and the corrections to the Dirac equation in a non-inertial frame, according to general relativity, are used as example cases in order to investigate the unitarity of the standard and 'chiral' approaches to the Foldy–Wouthuysen transformation, and spurious parity-breaking terms. Indeed, we find that parity-violating terms can be generated by unitary pseudo-scalar transformations ('chiral' Foldy–Wouthuysen transformations). Despite their interesting algebraic properties, we find that 'chiral' Foldy–Wouthuysen transformations change fundamental symmetry properties of the Hamiltonian and do not conserve the physical interpretation of the operators. Supplementing the discussion, we calculate the leading terms in the Foldy–Wouthuysen transformation of the Dirac Hamiltonian with a scalar potential (of the 1/r-form and of the confining radially symmetric linear form), and obtain compact expressions for the leading higher-order corrections to the Dirac Hamiltonian in a non-inertial rotating reference frame ('Mashhoon term').
On the Singularity of Random Bernoulli Matrices — Novel Integer Partitions and Lower Bound Expansions

We prove a lower bound expansion on the probability that a random ±1 matrix is singular, and conjecture that such expansions govern the actual probability of singularity. These expansions are based on naming the most likely, second most likely, and so on, ways that a Bernoulli matrix can be singular; the most likely way is to have a null vector of the form ei ±e j , which corresponds to the integer partition 11, with two parts of size 1. The second most likely way is to have a null vector of the form ei ±e j ±ek ±el, which corresponds to the partition 1111. The fifth most likely way corresponds to the partition 21111. We define and characterize the “novel partitions” which show up in this series. As a family, novel partitions suffice to detect singularity, i.e., any singular Bernoulli matrix has a left null vector whose underlying integer partition is novel. And, with respect to this property, the family of novel partitions is minimal. We prove that the only novel partitions with six or fewer parts are 11, 1111, 21111, 111111, 221111, 311111, and 322111. We prove that there are fourteen novel partitions having seven parts. We formulate a conjecture about which partitions are “first place and runners up” in relation to the Erdős-Littlewood-Offord bound. We prove some bounds on the interaction between left and right null vectors.
Unusually Large 13C NMR Chemical Shift Differences between Neutral and Protonated Glycocyamidines. New Insights on Previously Reported Chemical Shift Assignments and Chemical Properties

Unusually large 13C chemical shift differences are observed between neutral and protonated glycocyamidine (2-aminoimidazolinone) derivatives. Upon protonation, the guanidine (N−CN) and carbonyl (CO...
Auger electron spectroscopy study of GaAs layer growth on InP substrate

Abstract A new molecular beam epitaxy (MBE) growth procedure is developed for the purpose of controlling the atomic layer number and obtaining a smooth atomic layer without surface steps. Three GaAs monolayers on an InP substrate could be formed by a monolayer-by-monolayer growth process which was studied by measuring the Auger In peak intensities of the InP substrate. The Auger electron escape length of In (401 eV), which was estimated after the growth of one, two and three GaAs monolayers, was about 7.3, 7.4 and 7.4 A, respectively. In addition, it was observed that even three GaAs monolayers could protect the InP surface from P desorption at high temperatures and chemical damage by hydrochloric acid.
A direct mechanism characterization of sequential bargaining with one-sided incomplete information

We characterize the sequential equilibria of a class of infinite-horizon bargaining games with one-sided incomplete information. When the seller (the uninformed party) makes all the offers, we prove a folk theorem: every incentive compatible, individually rational, direct bargaining mechanism is implementable by sequential equilibria. Introducing buyer counteroffers eliminates outcomes which are unfavorable to that party. As the proportion of buyer offers increases, the set of implementable mechanisms shrinks continuously; when the proportion reaches one, only the single outcome most favorable to the buyer remains. Thus, depending on the offer structure, sequentiality may (or may not) impose restrictions beyond static incentive compatibility.
Multivariable feedback particle filter

This paper presents the multivariable extension of the feedback particle filter (FPF) algorithm for the nonlinear filtering problem in continuous-time. The FPF is a control-oriented approach to particle filtering. The approach does not require importance sampling or resampling and offers significant variance improvements; in particular, the algorithm can be applied to systems that are not stable. This paper describes new representations and algorithms for the FPF in the general multivariable nonlinear non-Gaussian setting. Theory surrounding the FPF is improved: Exactness of the FPF is established in the general setting, as well as well-posedness of the associated boundary value problem to obtain the filter gain. A Galerkin finite-element algorithm is proposed for approximation of the gain. Its performance is illustrated in numerical experiments.
Facile Synthesis of New L‐Arginine Derivatives as Substrates for Trypsin‐Like Proteases

Abstract Facile and efficient synthetic routes for fluorogenic anilides of L‐arginine have been developed. The amide bond formation uses phosphorous oxychloride as a condensing agent. The synthesis is simple, rapid, and affords excellent yields.
Joint digital signal processing for superchannel coherent optical systems: Joint CD compensation for joint ICI cancellation

A joint digital signal processing strategy for superchannel systems is introduced and demonstrated to improve system performance over 1280-km SSMF. Joint chromatic dispersion compensation is shown to enable joint inter-channel interference cancellation dramatically reducing spectral generation and detection constraints within superchannel systems.
Annihilators of graded components of the canonical module, and the core of standard graded algebras

We relate the annihilators of graded components of the canonical module of a graded Cohen-Macaulay ring to colon ideals of powers of the homogeneous maximal ideal. In particular, we connect them to the core of the maximal ideal. An application of our results characterizes Cayley-Bacharach sets of points in terms of the structure of the core of the maximal ideal of their homogeneous coordinate ring. In particular, we show that a scheme is Cayley-Bacharach if and only if the core is a power of the maximal ideal.
Quantum induced soft supersymmetry breaking in supergravity

We calculate the one-loop quantum contributions to soft supersymmetry breaking terms in the scalar potential in supergravity theories regulatedla Pauli-Villars. We find "universal" contributions, independent of the regulator masses and tree level soft supersymmetry breaking, that contribute gaugino masses and A-terms equal to the "anomaly mediated" contributions found in analyses using spurion techniques, as well as a scalar mass term not identified in those analyses. The universal terms are in general modified - and in some cases canceled - by model- dependent terms. Under certain restrictions on the couplings we recover the one-loop results of previous "anomaly mediated" supersymmetry breaking scenarios. We emphasize the model dependence of loop-induced soft terms in the potential, which are much more sensitive to the details of Planck scale physics then are the one-loop contributions to gaugino masses. We discuss the relation of our results to previous analyses.
Gravitational-wave measurements of the mass and angular momentum of a black hole.

A deformed black hole produced in a cataclysmic astrophysical event should undergo damped vibrations which emit gravitational radiation. By fitting the observed gravitational waveform h(t) to the waveform predicted for black-hole vibrations, it should be possible to deduce the hole’s mass M and dimensionless rotation parameter a=(c/G)(angular momentum)/M^2. This paper estimates the accuracy with which M and a can be determined by optimal signal processing of data from laser-interferometer gravitational-wave detectors. It is assumed that the detector noise has a white spectrum and has been made Gaussian by cross correlation of detectors at different sites. Assuming, also, that only the most slowly damped mode (which has spheroidal harmonic indices l=m=2) is significantly excited—as probably will be the case for a hole formed by the coalescence of a neutron-star binary or a black-hole binary—it is found that the one-sigma uncertainties in M and a are ΔM/M≃2.2ρ^-1(1-a)^0.45, Δa≃5.9ρ^-1(1-a)^1.06, where ρ≃hs(πSh)^-1/2 (1-a)^-0.22. Here ρ is the amplitude signal-to-noise ratio at the output of the optimal filter, hs is the wave’s amplitude at the beginning of the vibrations, f is the wave’s frequency (the angular frequency ω divided by 2π), and Sh is the frequency-independent spectral density of the detectors’ noise. These formulas for ΔM and Δa are valid only for ρ≳10. Corrections to these approximate formulas are given in Table II.
General method for the synthesis of N-methyl amino acids and N-alkyl amino esters from O'Donnell's Schiff bases

Abstract N-methyl amino acids, including L-abrine, and N-alkyl amino esters, were synthesized by reductive amination of O'Donnell's Schiff base amino esters with NaBH 3 CN and formaldehyde, or the appropriate aldehyde in CH 3 CN or THF in good to excellent yields, and with high purity.
On Li-Yorke measurable sensitivity

The notion of Li-Yorke sensitivity has been studied extensively in the case of topological dynamical systems. We introduce a measurable version of Li-Yorke sensitivity, for nonsingular (and measure-preserving) dynamical systems, and compare it with various mixing notions. It is known that in the case of nonsingular dynamical systems, ergodic Cartesian square implies double ergodicity, which in turn implies weak mixing, but the converses do not hold in general, though they are all equivalent in the finite measure-preserving case. We show that for nonsingular systems, ergodic Cartesian square implies Li-Yorke measurable sensitivity, which in turn implies weak mixing. As a consequence we obtain that, in the finite measure-preserving case, Li-Yorke measurable sensitivity is equivalent to weak mixing. We also show that with respect to totally bounded metrics, double ergodicity implies Li-Yorke measurable sensitivity.
Study of QCD critical point using canonical ensemble method

Abstract The existence of the QCD critical point at non-zero baryon density is not only of great interest for experimental physics but also a challenge for the theory. We use lattice simulations based on the canonical ensemble method to explore the finite baryon density region and look for the critical point. We scan the phase diagram of QCD with three degenerate quark flavors using clover fermions with m π ≈ 700 MeV on 6 3 × 4 lattices. We measure the baryon chemical potential as we increase the density and we see the characteristic “S-shape” that signals the first order phase transition. We determine the phase boundary by Maxwell construction and report our preliminary results for the location of critical point.
Imaging interferometric microscopy

We introduce and demonstrate a new microscopy concept: imaging interferometric microscopy (IIM), which is related to holography, synthetic-aperture imaging, and off-axis–dark-field illumination techniques. IIM is a wavelength-division multiplex approach to image formation that combines multiple images covering different spatial-frequency regions to form a composite image with a resolution much greater than that permitted by the same optical system using conventional techniques. This new type of microscopy involves both off-axis coherent illumination and reinjection of appropriate zero-order reference beams. Images demonstrate high resolution, comparable with that of a high-numerical-aperture (NA) objective, while they retain the long working distance, the large depth of field, and the large field of view of a low-NA objective. A Fourier-optics model of IIM is in good agreement with the experiment.
Parity and risk of hip fracture in postmenopausal women

Hip fracture risk was assessed according to parity among postmenopausal women. Compared with nulliparous women, the fracture risk was lower in women with three or more births. Parity was assessed for long-term prediction of hip fracture in postmenopausal women. Postmenopausal women (n = 2,028) aged 45 or over with no history of hip fracture were studied. From 1978 to 1980, all of them had participated in a comprehensive health survey based on a nationally representative population sample. Emerging cases of hip fracture were identified from the National Hospital Discharge Register during a follow-up period extending up to 17 years. The risk of hip fracture was lower among parous women compared with nulliparous women. The model adjusted for age showed a significant inverse association between parity as a continuous variable and the risk of hip fracture [RR = 0.74; 95% confidence interval (CI), 0.61–0.90] per an increment of one standard deviation (2.4 births). Adjusted for age, menopausal age, level of education, body mass index, vitamin D status, alcohol consumption, smoking history, leisure time physical activity, and self-rated health, the relative risk was 0.50 (95% CI, 0.32–0.79) for women with three or more births and 0.85 (95% CI, 0.55–1.32) for women with one to two births as compared with nulliparous women. Parity, three or more births in particular, predicts a lowered risk of hip fracture in the long run.
Synthesis of new multidentate ligands for the coordination of indium(iii), gadolinium(iii) and thorium(iv)

Abstract Efficient syntheses are described for five new multidentate ligands containing 3-hydroxy-6-methyl-2-pyridyl donor groups: 4,7,10-tris(3-hydroxy-6-methyl-2-pyridylmethyl)-1-oxa-4,7, 10-triazacyclododecane, 2 ; 4,10,13-tris(3-hydroxy-6-methyl-2-pyrildylmethyl)-1,7-dioxa-4,10,13-triazacyclopentadecane, 3 ; 4,10,16-tris(3-hydroxy-6-methyl-2-pyridylmethyl)-1,7,13-trioxa-4,10,16-triazacyclooctadecane, 4 ; 1,4,7,10-tetrakis(3-hydroxy-6-methyl-2-pyridylmethyl-1,4,7,10-tetraazacyclododecane, 5 ; 1,4,8,11 -tetrakis(3-hydroxy-6-methyl-2-pyridylmethyl)-1,4,8,11-tetraazacyclotetradecane. 2 , 3 , and 4 are designed for the coordination of In(III) and Gd(III): 5 and 6 are for Th(IV).
A Perspective on Free Radical Autoxidation: The Physical Organic Chemistry of Polyunsaturated Fatty Acid and Sterol Peroxidation

This Perspective describes advances from the author’s laboratory on the free radical reactions of organic compounds with molecular oxygen. Polyunsaturated fatty acids (PUFAs) and sterols are particularly prone to undergo radical chain oxidation, and evidence suggests that this process, known as lipid peroxidation, occurs in vivo under a variety of conditions that are the result of an oxidative stress. Cyclic peroxides, hydroperoxides, and epoxy alcohols are major products formed from peroxidation, and the basic mechanisms of product formation are now reasonably well understood. These mechanisms include reversible addition of oxygen to carbon radicals, rearrangement and cyclization of allyl and pentadienyl peroxyl radicals, and homolytic substitution of carbon radicals on the peroxide bond. A physical organic approach to the problem of free radicals in biology and medicine is highlighted in this Perspective with stereochemical, kinetic, and extrathermodynamic probes applied to the study of mechanism. A rad...
Stable isoporphyrin chromophores: synthesis

Abstract Condensation of a 5,5-disubstituted-dipyrromethanes (6a, 6b) with a 1,9-diformyl-pyrromethane (7) under MacDonald conditions in the presence of zinc(II) acetate affords zinc(II) salts (8a, 8b) possessing the isoporphyrin chromophore, which is stable with respect to transformation into porphyrin; some spectroscopic properties of (8a) and (8b) are described.
Assembly and N-glycosylation of all ACh receptor subunits are required for their efficient insertion into plasma membranes

Various combinations of synthetic acetylcholine receptor (AChR) subunit mRNAs were injected into Xenopus oocytes, and assembly of incomplete AChRs and their insertion into the plasma membrane was studied. Assembly of incomplete AChRs is not greatly affected by the absence of one or two of the other subunits. In contrast, the membrane insertion of incomplete AChRs is profoundly reduced as compared with complete AChRs. The role of N-glycosylation on the assembly of AChR subunits, and on their insertion into plasma membranes, was also studied by using the Xenopus oocyte expression system and tunicamycin. Assembly of non-N-glycosylated AChR subunits occurs in tunicamycin-treated oocytes, but these subunits remain in intracellular compartments, suggesting that N-glycosylation of AChR subunits is not a prerequisite for receptor assembly, but is required for their efficient insertion into the plasma membrane.
Combustor stability and emissions research using a well-stirred reactor

The design and development of low-emissions, lean premixed aero or industrial gas turbine combustors is very challenging because it entails many compromises. To satisfy the projected CO and NO{sub x} emissions regulations without relaxing the conflicting requirements of combustion stability, efficiency, pattern factor, relight (for aero combustor), or off-peak loading (for industrial combustor) capability demands great design ingenuity. The well-stirred reactor (WSR) provides a laboratory idealization of an efficient and highly compact advanced combustion system of the future that is capable of yielding global kinetics of value to the combustor designers. In this paper, they have studied the combustion performance and emissions using a toroidal WSR. It was found that the toroidal WSR was capable of peak loading almost twice as high as that for a spherical WSR and also yielded a better fuel-lean performance. A simple analysis based upon WSR theory provided good predictions of the WSR lean blowout limits. The WSR combustion efficiency was 99% over a wide range of mixture ratios and reactor loading. CO emissions reached a minimum at a flame temperature of 1,600 K and NO{sub x} increased rapidly with an increase in flame temperature, moderately with increasing residence time, and peaked at or slightlymore » on the fuel-lean side of the stoichiometric equivalence ratio. Finally, emissions maps of different combustors were plotted and showed that the WSR has the characteristics of an idealized high-efficiency, low-emissions combustor of the future.« less
Lower bounds on precedence-constrained scheduling for parallel processors

We consider two general precedence-constrained scheduling problems that have wide applicability in the areas of parallel processing, high performance compiling, and digital system synthesis. These problems are intractable so it is important to be able to compute tight bounds on their solutions. A tight lower bound on makespan scheduling can be obtained by replacing precedence constraints with release and due dates, giving a problem that can be efficiently solved. We demonstrate that recursively applying this approach yields a bound that is provably tighter than other known bounds, and experimentally shown to achieve the optimal value at least 90.3% of the time over a synthetic benchmark.We compute the best known lower bound on weighted completion time scheduling by applying the recent discovery of a new algorithm for solving a related scheduling problem. Experiments show that this bound significantly outperforms the linear programming-based bound. We have therefore demonstrated that combinatorial algorithms can be a valuable alternative to linear programming for computing tight bounds on large scheduling problems.
Subleading contributions from instanton corrections in N = 2 supersymmetric black hole entropy

Abstract We present subleading corrections to the N = 2 supersymmetric black hole entropy. These subleading contributions correspond to instanton corrections of the Type II string theory. In particular we consider an axion free black hole solution of low-energy effective Type II string theory. We present a procedure to include successiveall instanton corrections. Expanding these corrections at particular points in moduli space yields polynomial and logarithmic instanton corrections to the classical black hole entropy. We comment on a microscopic interpretation of these instanton corrections and find that the logarithmic corrections correspond to subleading terms in the degeneracy of the spectrum of an underlying quantum theory.
Sufficient conditions for uniqueness of the weak value

We review and clarify the sufficient conditions for uniquely defining the generalized weak value as the weak limit of a conditioned average using the contextual values formalism introduced in Dressel, Agarwal and Jordan (2010 Phys. Rev. Lett. 104 240401). We also respond to criticism of our work by Parrott (arXiv:1105.4188v1) concerning a proposed counter-example to the uniqueness of the definition of the generalized weak value. The counter-example does not satisfy our prescription in the case of an underspecified measurement context. We show that when the contextual values formalism is properly applied to this example, a natural interpretation of the measurement emerges and the unique definition in the weak limit holds. We also prove a theorem regarding the uniqueness of the definition under our sufficient conditions for the general case. Finally, a second proposed counter-example by Parrott (arXiv:1105.4188v6) is shown not to satisfy the sufficiency conditions for the provided theorem.
Stress-energy tensor in colliding plane wave space-times: An approximation procedure

In a recent work on the quantization of a massless scalar field in a particular colliding plane wave space-time, we computed the vacuum expectation value of the stress-energy tensor on the physical state which corresponds to the Minkowski vacuum before the collision of the waves. We did such a calculation in a region close to both the Killing-Cauchy horizon and the folding singularities that such a space-time contains. In the present paper, we give a suitable approximation procedure to compute this expectation value, in the conformal coupling case, throughout the causal past of the center of the collision. This will allow us to approximately study the evolution of such an expectation value from the beginning of the collision until the formation of the Killing-Cauchy horizon. We start with a null expectation value before the arrival of the waves, which then acquires non-zero values at the beginning of the collision and grows unbounded towards the Killing-Cauchy horizon. The value near the horizon is compatible with our previous result, which means that such an approximation may be applied to other colliding plane wave space-times. Even with this approximation, the initial modes propagated into the interaction region contain a function which cannot be calculated exactly and to ensure the correct regularization of the stress-energy tensor with the point-splitting technique, this function must be given up to adiabatic order four of approximation.
The effect of oxygen concentration on the reduction of NO with propylene over CuO/γ-Al2O3

Abstract The effect of oxygen concentration on the pulse and steady-state selective catalytic reduction (SCR) of NO with C3H6 over CuO/γ-Al2O3 has been studied by infrared spectroscopy (IR) coupled with mass spectroscopy studies. IR studies revealed that the pulse SCR occurred via (i) the oxidation of Cu0/Cu+ to Cu2+ by NO and O2, (ii) the co-adsorption of NO/NO2/O2 to produce Cu2+(NO3−)2, and (iii) the reaction of Cu2+(NO3−)2 with C3H6 to produce N2, CO2, and H2O. Increasing the O2/NO ratio from 25.0 to 83.4 promotes the formation of NO2 from gas phase oxidation of NO, resulting in a reactant mixture of NO/NO2/O2. This reactant mixture allows the formation of Cu2+(NO3−)2 and its reaction with the C3H6 to occur at a higher rate with a higher selectivity toward N2 than the low O2/NO flow. Both the high and low O2/NO steady-state SCR reactions follow the same pathway, proceeding via adsorbed C3H7NO2, C3H7ONO, CH3COO−, Cu0CN, and Cu+NCO intermediates toward N2, CO2, and H2O products. High O2 concentration in the high O2/NO SCR accelerates both the formation and destruction of adsorbates, resulting in their intensities similar to the low O2/NO SCR at 523–698 K. High O2 concentration in the reactant mixture resulted in a higher rate of destruction of the intermediates than low O2 concentration at temperatures above 723 K.
5th international workshop on networking meets databases (NetDB 2009)

The Workshop on Networking Meets Databases (NetDB) is a venue that aims to bring together researchers from the systems and networking community and the database community. Many current research areas, such as cloud computing, data-center networking, sensor networks, network management, or social networks, raise research problems that lie at the boundary between these two communities. The workshop’s goal is to foster an environment in which researchers from both communities can discuss ideas that will shape and influence these emerging research areas. The workshop encourages submissions of early work, with novel and interesting ideas. The expectation is that work introduced at NetDB, once fully thought through, completed, and described in a finished form, may be relevant to conferences such as SOSP, OSDI, SIGCOMM, SIGMOD, VLDB, NSDI, or ICDE. Traditionally, NetDB has been co-located with either the IEEE International Conference on Data Engineering (ICDE’05, ICDE’06, ICDE’08) or the USENIX Symposium on Networked Systems Design and Implementation (NSDI’08). This year is the first time when the workshop was co-located with the ACM Symposium on Operating Systems Principles (SOSP). By co-locating with SOSP, we aimed at raising the interest from the wider systems community on topics relevant to NetDB.
Nonlinear Instability for the Navier-Stokes Equations

It is proved, using a bootstrap argument, that linear instability implies nonlinear instability for the incompressible Navier-Stokes equations in L p for all p ∈ (1,∞) and any finite or infinite domain in any dimension n.
Remarks on the Formulation of the Cosmological Constant/Dark Energy Problems

Associated with the cosmic acceleration are the old and new cosmological constant problems, recently put into the more general context of the dark energy problem. In broad terms, the old problem is related to an unexpected order of magnitude of this component while the new problem is related to this magnitude being of the same order of the matter energy density during the present epoch of cosmic evolution. Current plans to measure the equation of state or density parameters certainly constitute an important approach; however, as we discuss, this approach is faced with serious feasibility challenges and is limited in the type of conclusive answers it could provide. Therefore, is it really too early to seek actively for new tests and approaches to these problems? In view of the difficulty of this endeavor, we argue in this work that a good place to start is by questioning some of the assumptions underlying the formulation of these problems and finding new ways to put this questioning to the test. First, we calculate how much fine tuning the cosmic coincidence problem represents. Next, we discuss the potential of some cosmological probes such as weak gravitational lensing to identify novel tests to probe dark energy questions and assumptions and provide an example of consistency tests. Then, motivated by some theorems in General Relativity, we discuss if the full identification of the cosmological constant with vacuum energy is unquestionable. We discuss some implications of the simplest solution for the principles of General Relativity. Also, we point out the relevance of experiments at the interface of astrophysics and quantum field theory, such as the Casimir effect in gravitational and cosmological contexts. We conclude that challenging some of the assumptions underlying the cosmological constant problems and putting them to the test may prove useful and necessary to make progress on these questions.
Penetration into dry porous rock: A numerical study on sliding friction simulation

Abstract Penetration of Antelope tuff targets by steel penetrators is the subject of discussion in the present investigation. Specifically, the effect of sliding friction between projectile and target on penetration is examined. The finite element code PRONTO 2D is used to perform a parametric study of the coefficient of friction. Both constant and velocity dependent coefficient of friction representation have been included in the current investigation. Results indicate that increases in the coefficient of friction increase the penetration resistance although the relationship is nonlinear in nature. In terms of peak deceleration and depth of penetration, both the constant and velocity dependent coefficient of friction representation provide almost identical results. However, only the velocity dependent cases show the characteristic of increasing deceleration prior to the conclusion of the penetration event. For this reason, the velocity dependent representation of the coefficient of friction is preferred over the constant friction coefficient representation.
Selective N-Sulfation of Glucosamine Derivatives using Phenyl Chlorosulfate in Non-Aqueous Solvent

Abstract The selective N-sulfation of 2-amino-2-deoxy-D-glucopyranose derivatives having unprotected hydroxyl groups with phenyl chlorosulfate and triethylamine in anhydrous organic solvent followed by addition of aqueous sodium bicarbonate affords high yields of the 2-deoxy-2-sulfoamino-D-glucopyranose products.
Reconstruction-based contribution for process monitoring

This paper presents a new method to perform fault diagnosis for data-correlation based process monitoring. As an alternative to the traditional contribution plot method, a reconstruction-based contribution for fault diagnosis is proposed based on monitored indices, SPE, T^2 and a combined index @f. Analysis of the diagnosability of the traditional contributions and the reconstruction-based contributions is performed. The lack of diagnosability of traditional contributions is analyzed for the case of single sensor faults with large fault magnitudes, whereas for the same case the proposed reconstruction-based contributions guarantee correct diagnosis. Monte Carlo simulation results are provided for the case of modest fault magnitudes by randomly assigning fault sensors and fault magnitudes.
DNA‐decorated carbon nanotubes for chemical sensing

We demonstrate a versatile class of nanoscale chemical sensors based on single-stranded DNA (ssDNA) for chemical recognition and single-walled carbon nanotube field effect transistors (SWNT FETs) for electronic read-out. SWNT FETs with a nanoscale coating of ssDNA respond to vapors that cause no detectable conductivity change in bare devices. Sensor responses differ in sign and magnitude for different gases and can be tuned by choice of the ssDNA base sequence. Sensors respond and recover rapidly (seconds), and the sensor surface is self-regenerating. Preliminary results of all-atom molecular dynamics simulations agree with experiment.
Homotopy curve tracking in approximate interior point optimization

In a previous work the authors developed an interior point approach for trust region managed sequential approximate optimization. The interior point approach insures that approximate feasibility is maintained throughout the optimization process. In the case of an infeasible starting point, a relaxation of the constraints allows the algorithm to operate without modification. The relaxation is controlled by a homotopy parameter. A primary advantage resides in the fact that all the constraints (contrasted with just the active or most violated constraints) influence the optimization, since the relaxation fades at the same time for all violated constraints. Adjustment of the parameter was performed in an heuristic fashion. In this paper the authors present a robust methodology to update the homotopy parameter based on the theory of probability-one homotopies for nonlinear programming. Results show that the method is robust and effective in its implementation for achieving sequential approximate optimization feasibility.
The fleeting nature of permanent reinvestment: Accounting for the undistributed earnings of foreign subsidiaries

Abstract Over the last decade, an increasing percentage of the profits reported by U.S. corporations were earned by their foreign subsidiaries and retained outside the United States resulting in the deferral of income taxes. The American Jobs Creation Act of 2004 provided a temporary federal tax incentive to remit such earnings, which resulted in the repatriation of $140 billion by the 30 firms comprising the Dow Jones Industrial Average. An analysis of the financial reporting disclosures made by these firms reveals that a tax expense was not fully recognized on a substantial portion of the earnings until repatriation because of an exception for foreign reinvestments deemed to be essentially permanent in duration. The implications of the currently acceptable accounting for undistributed foreign earnings are discussed as well as recommendations to improve the relevancy and reliability of the disclosures required for this exception to comprehensive recognition of deferred taxes.
Random holomorphic iterations and degenerate subdomains of the unit disk

Given a random sequence of holomorphic maps f 1 , f 2 , f 3 ,... of the unit disk A to a subdomain X, we consider the compositions F n = fl f 2 ... f n-1 0 f n . The sequence {F n } is called the iterated function system coming from the sequence f 1 , f 2 , f 3 .... We prove that a sufficient condition on the domain X for all limit functions of any {F n } to be constant is also necessary. We prove that the condition is a quasiconformal invariant. Finally, we address the question of uniqueness of limit functions.
Risk, Transaction Costs, and Tax Assignment: Government Finance in the Ottoman Empire

Risk and transaction costs often provide competing explanations of institutional outcomes. In this article we argue that they offer opposing predictions regarding the assignment of fixed and variable taxes in a multi-tiered governmental structure. Although the central government can pool regional risks from variable taxes, local governments can measure variable tax bases more accurately. Evidence on tax assignment from the mid-sixteenth-century Ottoman Empire supports the transaction cost explanation, suggesting that risk matters less because insurance can be obtained in a variety of ways.