cssi/SciSciGPT-SciSciNet huggingface dataset:
Peptoid Oligomers with α-Chiral, Aromatic Side Chains: Effects of Chain Length on Secondary Structure

Oligomeric N-substituted glycines or “peptoids” with α-chiral, aromatic side chains can adopt stable helices in organic or aqueous solution, despite their lack of backbone chirality and their inability to form intrachain hydrogen bonds. Helical ordering appears to be stabilized by avoidance of steric clash as well as by electrostatic repulsion between backbone carbonyls and π clouds of aromatic rings in the side chains. Interestingly, these peptoid helices exhibit intense circular dichroism (CD) spectra that closely resemble those of peptide α-helices. Here, we have utilized CD to systematically study the effects of oligomer length, concentration, and temperature on the chiral secondary structure of organosoluble peptoid homooligomers ranging from 3 to 20 (R)-N-(1-phenylethyl)glycine (Nrpe) monomers in length. We find that a striking evolution in CD spectral features occurs for Nrpe oligomers between 4 and 12 residues in length, which we attribute to a chain length-dependent population of alternate struct...
Identification of Two Distinctive Types of Centimeter Radio Bursts with Flare Location

Two distinct types of centimeter solar bursts, classified ‘simple’, have been identified and related to the position (with respect to a sunspot) of the related flare. Type S in which the flare occurs directly over the spot has a radio spectrum with a maximum beyond 10 GHz, type P which occurs away from the spot has its maximum occurring near 3 GHz. Considering the structure of the spot magnetic field and invoking the synchrotron effect, it is shown that the origin of the radio burst may be attributed to a burst of energetic electrons with an energy peak near 3 MeV.
Synthesis, structure determination, and electronic structure characterization of two mixed-Valence tetranuclear platinum blues with bridging α-pyridonate or 1-methyluracilate ligands

[(en) Pt (C 5 H 4 NO) 2 Pt (en)] 2 (NO 3 ) 5• H 2 O et [(H 3 N) 2 Pt (C 5 H 5 -N 2 O 2 ) 2 Pt (NH 3 ) 2 ] 2 (NO 3 ) 5 •5H 2 O cristallisent dans le systeme triclinique, groupe d'espace P1 et leur structure est affinee respectivement jusqu'a R=0,0305 et R=0,0388
Synthesis and characterization of a neutral six-coordinate tris-adduct of an indium(III) trihalide. X-ray crystal structure of InCl3(THF)3

Abstract The reaction of InCl 3 with excess THF afforded the adduct InCl 3 (THF) 3 in a good yield (77.1% based on InCl 3 ), and the X-ray crystal structure shows it to be a hexa-coordinated tris-adduct of indium(III) chloride. The crystal structure consists of discrete monomeric units with no abnormally short intermolecular separations. The geometry about the indium atom approximates to octahedral with the three chlorine atoms (mean InCl = 2.422 A) and the oxygen atoms of each THF molecule (mean InO = 2.254 A) residing in the meridional conformation. IR spectroscopic measurements gave absorption bands near 1027 and 857 cm −1 , which are consistent with coordinated THF molecules. Variable temperature NMR studies showed that the tris-adduct was stable to disproportionation in solution between 20 and 60°C.
Atmospheric neutrinos in Super-Kamiokande

Abstract In this paper I will present the updated results from the Super-Kamiokande atmospheric neutrino analysis. We have now completed the analysis of 1144 live days of data corresponding to an exposure of 70 kt-years. I will discuss our measurements of contained, partially contained and entering events and the flavor ratio and angular distribution of the observed neutrino events. Using these observations, we calculate the neutrino oscillation parameters that best represent the data and our limits on a sterile neutrino interpretation of the oscillation.
PLANET-PLANET SCATTERING IN PLANETESIMAL DISKS

We study the final architecture of planetary systems that evolve under the combined effects of planet-planet and planetesimal scattering. Using N-body simulations we investigate the dynamics of marginally unstable systems of gas and ice giants both in isolation and when the planets form interior to a planetesimal belt. The unstable isolated systems evolve under planet-planet scattering to yield an eccentricity distribution that matches that observed for extrasolar planets. When planetesimals are included the outcome depends upon the total mass of the planets. For M tot 1 MJ the final eccentricity distribution remains broad, whereas for M tot 1 MJ a combination of divergent orbital evolution and recircularization of scattered planets results in a preponderance of nearly circular final orbits. We also study the fate of marginally stable multiple planet systems in the presence of planetesimal disks, and find that for high planet masses the majority of such systems evolve into resonance. A significant fraction leads to resonant chains that are planetary analogs of Jupiter's Galilean satellites. We predict that a transition from eccentric to near-circular orbits will be observed once extrasolar planet surveys detect sub-Jovian mass planets at orbital radii of a 5-10 AU.
Chandra Observations of 12 Luminous Red Quasars

The authors present results of a study of 12 dust-reddened quasars with 0.4 < z < 2.65 and reddenings in the range 0.15 < E(B-V) < 1.7. They obtained ACIS-S X-ray spectra of these quasars, estimated the column densities towards them, and hence obtained the gas:dust ratios in the material obscuring the quasar. They detect all but one of the red quasars in the X-rays. Even though there is no obvious correlation between the X-ray determined column densities of the sources and their optical color or reddening, all of the sources show absorbed X-ray spectra. When they correct the luminosity for absorption, they can be placed among luminous quasars; therefore their objects belong to the group of high luminosity analogues of the sources contributing to the X-ray background seen in deep X-ray observations. Such sources are also found in serendipitous shallow X-ray surveys. There is a hint that the mean spectral slope of the red quasar is higher than that of normal, unobscured quasars, which could be an indication for higher accretion rates and/or an evolutionary effect. They investigate the number density of these sources compared to type 2 AGN based on the X-ray background and estimate how many moderate luminosity red quasars may be found in deep X-ray fields.
Population equilibrium in primitive societies.

Abstract The aboriginal distribution of population in North America is found not to be positively related to the richness of the natural environment, contrary to the predictions of the Malthusian model, the dominant one in Anthropology. Great abundance of some resources can encourage nomadism or raise the productivity of women, two determinants of the cost of children, which I find are associated with, lower aboriginal population density among a sample of tribes of North American Indians.
Bijections and symmetries for the factorizations of the long cycle

We study the factorizations of the permutation (1,2,?,n) into k factors of given cycle types. Using representation theory, Jackson obtained for each k an elegant formula for counting these factorizations according to the number of cycles of each factor. In the cases k=2,3 Schaeffer and Vassilieva gave a combinatorial proof of Jackson?s formula, and Morales and Vassilieva obtained more refined formulas exhibiting a surprising symmetry property. These counting results are indicative of a rich combinatorial theory which has remained elusive to this point, and it is the goal of this article to establish a series of bijections which unveil some of the combinatorial properties of the factorizations of (1,2,?,n) into k factors for all k. We thereby obtain refinements of Jackson?s formulas which extend the cases k=2,3 treated by Morales and Vassilieva. Our bijections are described in terms of "constellations", which are graphs embedded in surfaces encoding the transitive factorizations of permutations.
Determination of dissociation constants of polyprotic acids from chromatographic data

The separation and purification of drugs and biological compounds, which are typically weak polyprotic acids, by HPLC is the subject of numerous literature reports. The development of separation methodologies depends on the acid dissociation constants, and the HPLC offers a valuable method for determining these constants, especially when the compounds are poorly soluble in water. This review presents general basic equations and shows how they are used for determining the pKa's. It also discusses the parameters affecting the pKa's and the methods of their measurement as presented in a representative number of research papers published in the last 20 years.
On the stability and structural dynamics of metal nanowires

This article presents a brief review of the nanoscale free-electron model, which provides a continuum description of metal nanostructures. It is argued that surface and quantum-size effects are the two dominant factors in the energetics of metal nanowires, and that much of the phenomenology of nanowire stability and structural dynamics can be understood based on the interplay of these two competing factors. A linear stability analysis reveals that metal nanocylinders with certain magic conductance values G=1,3,6,12,17,23,34,42,51,67,78,96,... times the conductance quantum are exceptionally stable. A nonlinear dynamical simulation of nanowire structural evolution reveals a universal equilibrium shape consisting of a magic cylinder suspended between unduloidal contacts. The lifetimes of these metastable structures are also computed.
Scalar three-point functions in a CDL background

Motivated by the FRW-CFT proposal by Freivogel, Sekino, Susskind and Yeh, we compute the three-point function of a scalar field in a Coleman-De Luccia instanton background. We first compute the three-point function of the scalar field making only very mild assumptions about the scalar potential and the instanton background. We obtain the three-point function for points in the FRW patch of the CDL instanton and take two interesting limits; the limit where the three points are near the boundary of the hyperbolic slices of the FRW patch, and the limit where the three points lie on the past lightcone of the FRW patch. We expand the past lightcone three-point function in spherical harmonics. We show that the near boundary limit expansion of the three-point function of a massless scalar field exhibits conformal structure compatible with FRW-CFT when the FRW patch is flat. We also compute the three-point function when the scalar is massive, and explain the obstacles to generalizing the conjectured field-operator correspondence of massless fields to massive fields.
The yield of lower endoscopy in patients with constipation: Survey of a university hospital, a public county hospital, and a Veterans Administration medical center

Abstract Background: The role of endoscopy in the evaluation of constipation is controversial. The aim of this study was to clarify the yield of lower endoscopy in patients with constipation. Methods: Endoscopic databases from 3 diverse hospitals were searched for procedures with constipation as an indication. Detection of neoplasia was the main outcome of interest. Results: Among 19,764 sigmoidoscopies or colonoscopies, constipation was a procedure indication for 563 patients (mean age 61 [16] years, 52% women); 58% had procedure indications in addition to constipation. Colorectal cancer was diagnosed in 8 (1.4%), adenomas in 82 (14.6%), and advanced lesions (cancer or adenoma with malignancy, high-grade dysplasia, villous features, or size ≥10 mm) in 24 (4.3%). In the 358 patients who underwent colonoscopy, cancer was detected in 1.7%, adenomas in 19.6%, and advanced lesions in 5.9%. Two patients with cancer were less than 50 years of age. In as many as 6 patients with cancer, the tumor may have caused partial obstruction. Conclusions: The range of neoplasia in patients with constipation evaluated with lower endoscopy was comparable with what would be expected in asymptomatic subjects undergoing colorectal cancer screening. Although chronic constipation alone may not be an appropriate indication for lower endoscopy, age-appropriate colorectal cancer screening should be pursued when patients with constipation seek medical care. (Gastrointest Endosc 2002;56:325-32.)
A regioselective Ru-catalyzed alkene-alkyne coupling.

The reaction of silylalkynes and terminal alkenes proceeds with complete control of regioselectivity by the silyl substituent to give geometrically defined vinylsilanes. Since terminal alkynes normally give mixtures, protodesilylation of these adducts then constitutes a regioselective addition of terminal alkynes to terminal alkenes.
Modification of the Microstructure in Poloxamer Block Copolymer-Water-``Oil'' Systems by Varying the ``Oil'' Type

Amphiphilic block copolymers can self-assemble in the presence of selective solvents (water and oil) into a variety of different microstructures. The role that oil plays in the phase behavior and structure of copolymer-oil-water systems is the focus of the present investigation. We examined a poloxamer-type poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock copolymer (Pluronic F127: E 100 P 70 E 100 ) in ternary isothermal systems with water and each of three oils (of varying polarity), p-xylene, n-butyl acetate and butan-1-ol. A total of six phases with different microstructures have been identified in the ternary systems studied here: normal (oil-in-water) micellar cubic (I 1 ), normal hexagonal (H 1 ), lamellar (L α ), and reverse (water-in-oil) hexagonal (H 2 ) lyotropic liquid crystals, and normal micellar (L 1 ) and reverse micellar (L 2 ) solutions. The number and types of phases, as well as the composition range of their stability, are different for each ternary system, reflecting the effects of oil. Systematic small-angle X-ray scattering (SAXS) measurements have been performed in order to establish the structure of the phases and determine their characteristic length-scales. The location of the oils in the different self-assembled microstructures has been deduced from the structural dimensions obtained from SAXS and the constraints imposed by the copolymer total volume fraction and interfacial area: all xylene is present in the interior (apolar core) of the oil-in-water microdomains and butanol is located at the interfacial region between poly(propylene oxide) and poly(ethylene oxide), while butyl acetate contributes to both the core and the interfacial domains.
Stresses in Multilayered Cables

A theory is presented which will predict the stresses in a multilayered cable, subjected to axial, bending and torsional loads. In the axial case, the axial force and axial twisting moment are represented as linear combinations of the axial strain and the rotational strain. An analysis is also made of a cable subjected to axial loads and wrapped around a drum. The analysis involves a superposition of the stresses caused by the axial loads and the bending loads.
Geography of symplectic 4-manifolds with Kodaira dimension one

The geography problem is usually stated for simply connected symplectic 4-manifolds. When the first cohomology is nontrivial, however, one can restate the problem taking into account how close the symplectic manifold is to satisfying the conclusion of the Hard Lefschetz Theorem, which is measured by a nonnegative integer called the degeneracy. In this paper we include the degeneracy as an extra parameter in the geography problem and show how to fill out the geography of symplectic 4-manifolds with Kodaira dimension 1 for all admissible triples. AMS Classification 57R17; 53D05, 57R57, 57M60
Analyzing encryption protocols using formal verification techniques

An approach to analyzing encryption protocols using machine-aided formal verification techniques is presented. The properties that the protocol should preserve are expressed as state invariants, and the theorems that must be proved to guarantee that the cryptographic facility satisfies the invariants are automatically generated by the verification system. A formal specification of an example system is presented, and several weaknesses that were revealed by attempting to verify and test the specification formally are discussed. >
Analysis of Bloch’s Method in Structures with Energy Dissipation

Bloch analysis was originally developed to solve Schrodinger’s equation for the electron wave function in a periodic potential field, such as found in a pristine crystalline solid. In the context of Schrodinger’s equation, damping is absent and energy is conserved. More recently, Bloch analysis has found application in periodic macroscale materials, such as photonic and phononic crystals. In the vibration analysis of phononic crystals, structural damping is present together with energy dissipation. As a result, application of Bloch analysis is not straightforward and requires additional considerations in order to obtain valid results. It is the intent of this paper to propose a general framework for applying Bloch analysis in such systems. Results are presented in which the approach is applied to example phononic crystals. These results reveal the manner in which damping affects dispersion and the presence of band gaps in periodic systems.
The conditional breakdown properties of least absolute value local polynomial estimators

Nonparametric regression techniques provide an effective way of identifying and examining structure in regression data. The standard approaches to nonparametric regression, such as local polynomial...
Physiological responses of men working in fire fighting equipment in the heat.

On three separate occasions, 11 well conditioned fire fighters were tested on a treadmill at 40 km h−1 on a 10% grade for 15 min. The first two tests were conducted in the laboratory and the third ...
On the modeling, and open-loop control of a rotating thin flexible beam

A set of governing differential equations is derived for the inplane motion of a rotating thin flexible beam. The beam is assumed to be linearly elastic and is connected to a rigid hub driven by a torque motor. Both flexural and extensional effects are included in the derivation. This coupling due to flexure and extension is usually neglected in studies dealing with the control of such a system. Models for typical control studies are often derived by utilizing an assumed mode approach where the mode shapes are obtained by solving the Euler-Bernoulli beam equation for flexural vibrations, with clamped-free or pinned-free boundary conditions. The coupled equations developed in this paper are used to demonstrate that typical models in control studies give satisfactory results up to a critical rotational speed. For the case where these coupled equations are specialized to simple flexure only, valid for low angular speeds, a unique feedforward control strategy can be derived. This is an open-loop control strategy that enables total elimination of an a priori specified vibratory mode from the gross motion in a finite critical time.
Heat Transfer Enhancement in Narrow Channels Using Two and Three-Dimensional Mixing Devices

The localized enhancement of forced convection heat transfer in a rectangular duct with very small ratio of height to width (0.017) was experimentally explored. The heat transfer from a discrete square section of the wall was enhanced by raising the heat source off the wall in the form of a protrusion. Further enhancement was effected through the use of large-scale, three-dimensional roughness elements installed in the duct upstream of the discrete heat source. Transverse ribs installed on the wall opposite the heat source provided even greater heat transfer enhancement. Heat transfer and pressure drop measurements were obtained for heat source length-based Reynolds numbers of 2600 to 40,000 with a perfluorinated organic liquid coolant, FC-77, of Prandtl number 25.3. Selected experiments were also performed in water (Prandtl number 6.97) for Reynolds numbers between 1300 and 83,000, primarily to determine the role of Prandtl number on the heat transfer process. Experimental uncertainties were carefully minimized and rigorously estimated. The greatest enhancement in heat transfer relative to the flush heat source was obtained when the roughness elements were used in combination with a single rib on the opposite wall. A peak enhancement of 100 percent was obtained at a Reynolds number of 11,000,more » which corresponds to a transitional flow regime. Predictive correlations valid over a range of Prandtl numbers are proposed. 24 refs., 10 figs.« less
Energy capture and conversion by photosynthesis.

Abstract Electromagnetic energy with wavelengths from 400 mμ to 700 mμ is absorbed by pigment molecules—chlorophyll a and b , and accessory pigments—which are probably distributed over the surface of a large protein molecule. The resulting excited state of the pigments is tranferred from one pigment to another, until it reaches an organized array of chlroophyll molecules. There the energy of the excited state is converted by an essentially solid process to a charge separation between an electron and an electron hole. The electron eventually reduces an enzymic cofactor, TPN + making TPNH. The hole migrates through thw pigment array, until it can oxidize a cytochrome molecule. The oxidized cytochromes oxidize another coenzyme, and perhaps in the process produce ATP, this step being an enzymic raection. The oxidized coenzyme must in turn get electrons from water, and since this reaction requires a large input of energy it must also use light absorbed by the pigment systems. This oxidation of water somehow requires manganese, perhaps in the form of a pigment, Also, the water splitting reaction appears to utilize a different pigment system, and cannot be affected by absorptrion of light of wavelengths longer than 670 mμ. The transport of four electrons (liberating one O 2 molecule) requires six or eight photons, depending on the assumptions made, and produces two molecules of TPNH and two or more molecules of ATP. The overall efficiency for the production of these cofactors would not be as much as 50%, depending on the assumptions and based on the utilizayion of red (670 and 700 mμ) light. With shorter wavel;engths the energy efficiency decreases in proportion to wavelength. The coenzymes—three molecules of ATP and two of TPNH—are used with remarkable efficiency (perhaps 85%) to reduce CO 2 to carbohydrates and other products. ATP activates metabolites by increasing their energy content and making them more reactive towards carboxylation and reduction. TPNH, which carries the larger part of the chemical potential from the light reactions, reduces a carboxyl carbon to an aldehyde carbon. The energy of the coenzymes not stored as chemical potential in the final products provides the driving force to make a complex series of reactions proceed at a rapid rate in the forward direction.
Orbifold conformal blocks and the stack of pointed G-covers

Abstract Starting with a vertex algebra V, a finite group G of automorphisms of V, and a suitable collection of twisted V-modules, we construct (twisted) D-modules on the stack of pointed G-covers, introduced by Jarvis, Kaufmann, and Kimura. The fibers of these sheaves are spaces of orbifold conformal blocks defined in joint work with Edward Frenkel. The key ingredient is a G-equivariant version of the Virasoro uniformization theorem.
Sol−Gel Synthesis of Nanocrystalline Magnesium Fluoride: Its Use in the Preparation of MgF2 Films and MgF2−SiO2 Composites

Thin, protective films of nanocrystalline MgF2 were formed by spin-coating a sol that contained nanocrystalline MgF2, which was formed by the action of HF on a sol prepared from methanolic H2O2 and Mg(OCH3)2. These thin films on Si(100) lost fluoride to form MgO when heated at 550 °C. When the films on two such substrates were placed together face to face and heated at 550 °C, rough, abrasion resistant MgF2 films were obtained. To form composites, nanocrystalline MgF2 sols were mixed with silicate sols prepared from the acid catalyzed hydrolysis and condensation of tetramethyl orthosilicate (TMOS). X-ray diffraction and TEM analysis of xerogels and films obtained from these biphasic sols indicated nanocrystals of MgF2 dispersed in an amorphous matrix. On heating, fluoride loss and MgF2 crystal growth were both greatly retarded in powders and thin films prepared from silicate−MgF2 sols.
The impact of three new quaternary sulfides on the current predictive tools for structure and composition of diamond-like materials

Abstract Iron-containing diamond-like materials Ag2FeSiS4, Li2FeSnS4, and Li2FeGeS4 were synthesized for the first time via high-temperature, solid-state synthesis and found to adopt the wurtz–kesterite structure, crystallizing in the noncentrosymmetric space group Pn. These materials are considered in the broader context of design principles for new cubic- and hexagonal-derived diamond-like materials. All three of these new compounds violate Pauling’s radius ratio rule and Pfitzner’s tetrahedral volume theory. An evaluation of the adherence of over 40 published quaternary diamond-like structures to Pauling’s radius ratio rule and Pfitzner’s tetrahedral volume theory reveals that tetrahedral structures can often be generated even though these ideals are violated. To assess the radius ratios in diamond-like structures, an appropriate radii set must be selected. Accordingly, five radii sets have been investigated for accuracy in predicting metal–sulfur bond distances in diamond-like materials. Furthermore, a crystal radius of 1.63 A for four-coordinate S2− has been calculated using the metal–sulfur bond lengths of quaternary diamond-like materials and is proposed as an addition to the popular Shannon radii set.
How Frequent Are Small Price Changes

Abstract Recent empirical work suggests that small price changes are relatively common. This evidence has been used to criticize classic menu-cost models. In this paper, we use scanner data from a national supermarket chain and micro data from the Consumer Price Index to reassess the importance of small price changes. We argue that the vast majority of these changes are due to measurement error. We conclude that the evidence on the prevalence of small price changes is much too weak to be used as a litmus test of nominal rigidity models. (JEL C82, E31, L11, L81)
Improved Vehicle Reidentification and Travel Time Measurement on Congested Freeways

This paper presents an improved algorithm for matching individual vehicle measurements at a freeway detector station with the vehicles’ corresponding measurements taken at another detector station located upstream. The improvements consist of four new tests to identify incorrect matches and either replace them with the correct matches or discard the errors. The result is a higher number of reidentified vehicles with a lower frequency of errors compared to our earlier work. Although this algorithm is potentially compatible with many vehicle detector technologies, the paper illustrates the method using existing dual loop detectors to measure vehicle lengths. Due to the limited accuracy of the existing loop detector measurements under free flow conditions, this presentation is restricted to matching vehicles during congested traffic conditions. The algorithm is applied to individual lanes and exploits information about the sequence that vehicles pass the detectors. As such, the effect of vehicles changing la...
Implicitly threaded parallelism in manticore

The increasing availability of commodity multicore processors is making parallel computing ever more widespread. In order to exploit its potential, programmers need languages that make the benefits of parallelism accessible and understandable. Previous parallel languages have traditionally been intended for large-scale scientific computing, and they tend not to be well suited to programming the applications one typically finds on a desktop system. Thus, we need new parallel-language designs that address a broader spectrum of applications. The Manticore project is our effort to address this need. At its core is Parallel ML, a high-level functional language for programming parallel applications on commodity multicore hardware. Parallel ML provides a diverse collection of parallel constructs for different granularities of work. In this paper, we focus on the implicitly threaded parallel constructs of the language, which support fine-grained parallelism. We concentrate on those elements that distinguish our design from related ones, namely, a novel parallel binding form, a nondeterministic parallel case form, and the treatment of exceptions in the presence of data parallelism. These features differentiate the present work from related work on functional data-parallel language designs, which have focused largely on parallel problems with regular structure and the compiler transformations—most notably, flattening—that make such designs feasible. We present detailed examples utilizing various mechanisms of the language and give a formal description of our implementation.
Duplicate twins and double Monsters

Northampton, Mass., Dec. 15, 1904. To the Editor: —As I have recently become interested in a line of investigation which requires the careful examination of all forms of double monsters, I would be extremely grateful for the gift or loan of fetal or new-born specimens exhibiting any grade of this phenomenon. As such cases are rare, there is a natural tendency to store them up as museum specimens, in which condition the benefit to be derived from them is inconsiderable; while a thorough anatomic investigation would yield far more important results. As I am working on a definite problem, I do not care at present for other forms of monsters, such as those of microcephalous, acephalous or amorphous types, but only for those which exhibit a doubling of any axial part, ranging from single individuals with doubled median parts to two complete individuals united at a single point. Similar cases
Monte Carlo radiative transfer simulation for the near-ocean-surface high-resolution downwelling irradiance statistics

We present a numerical study of the near-surface underwater solar light statistics using the state-of-the-art Monte Carlo radiative transfer (RT) simulations in the coupled atmosphere-ocean system. Advanced variance-reduction techniques and full program parallelization are utilized so that the model is able to simulate the light field fluctuations with high spatial [O(10 −3 mm) ] and temporal [O(10 −3 mm) ] resolutions. In particular, we utilize the high-order correction technique for the beam-surface intersection points in the model to account for the shadowing effect of steep ocean surfaces, and therefore, the model is able to well predict the refraction and reflection of light for large solar zenith incidences. The Monte Carlo RT model is carefully validated by data-to-model comparisons using the Radiance in a Dynamic Ocean (RaDyO) experimental data. Based on the model, we are particularly interested in the probability density function (PDF) and coefficient of variation (CV) of the highly fluctuating downwelling irradiance. The effects of physical factors, such as the water turbidity of the ocean, solar incidence, and the detector size, are investigated. The results show that increased turbidity and detector size reduce the variability of the downwelling irradiance; the shadowing effect for large solar zenith incidence strongly enhances the variability of the irradiance at shallow depths.
A Selective Hypothesis Testing Perspective on Price-Quality Inference and Inference-Based Choice.

Consumers often rely heavily on price as a predictor of quality and typically overestimate the strength of this relation. Furthermore, the inferences of quality they make on the basis of price can influence their actual purchase decisions. Selective hypothesis testing appears to underlie the effects of information load and format on price–quality inferences. Results of 5 experiments converge on the conclusion that quality inferences are more heavily influenced by price when individuals have a high need for cognitive closure, when the amount of information presented is high (vs. low), and when the information presented is rank ordered in terms of quality rather than presented randomly. Furthermore, because consumers are willing to purchase more expensive brands when they perceive a high price–quality correlation, these variables can also influence their purchase decisions.
Is brane inflation eternal

In this paper, we show that eternal inflation of the random walk type is generically absent in the brane inflationary scenario. Depending on how the brane inflationary universe originated, eternal inflation of the false vacuum type is still quite possible. Since inflaton is the position of the D3-brane relative to the 3-brane inside the compactified bulk with finite size, its value is bounded. In DBI inflation, the warped space also restricts the amplitude of the scalar fluctuation. These upper bounds impose strong constraints on the possibility of eternal inflation. We find that eternal inflation due to the random walk of the inflaton field is absent in both the KKLMMT slow-roll scenario and the DBI scenario. A more careful analysis for the slow-roll case is also presented using the Langevin equation, which gives very similar results. We discuss possible ways to obtain eternal inflation of the random walk type in brane inflation. In the multi-throat brane inflationary scenario, the branes may be generated by quantum tunnelling and roll out the throat. Eternal inflation of the false vacuum type inevitably happens in this scenario due to the tunnelling process. Since these scenarios have different cosmological predictions, more data from the cosmic microwave background radiation will hopefully select the specific scenario our universe has gone through.
Schubert polynomials for the affine Grassmannian of the symplectic group

We study the Schubert calculus of the affine Grassmannian Gr of the symplectic group. The integral homology and cohomology rings of Gr are identified with dual Hopf algebras of symmetric functions, defined in terms of Schur’s P and Q functions. An explicit combinatorial description is obtained for the Schubert basis of the cohomology of Gr, and this is extended to a definition of the affine type C Stanley symmetric functions. A homology Pieri rule is also given for the product of a special Schubert class with an arbitrary one.
Oral calcium carbonate affects calcium but not phosphorus balance in stage 3–4 chronic kidney disease

Patients with chronic kidney disease (CKD) are given calcium carbonate to bind dietary phosphorus, reduce phosphorus retention, and prevent negative calcium balance; however, data are limited on calcium and phosphorus balance during CKD to support this. Here, we studied eight patients with stage 3 or 4 CKD (mean estimated glomerular filtration rate 36ml/min) who received a controlled diet with or without a calcium carbonate supplement (1500mg/day calcium) during two 3-week balance periods in a randomized placebo-controlled cross-over design. All feces and urine were collected during weeks 2 and 3 of each balance period and fasting blood, and urine was collected at baseline and at the end of each week. Calcium kinetics were determined using oral and intravenous 45 calcium. Patients were found to be in neutral calcium and phosphorus balance while on the placebo. Calcium carbonate supplementation produced positive calcium balance, did not affect phosphorus balance, and produced only a modest reduction in urine phosphorus excretion compared with placebo. Calcium kinetics demonstrated positive net bone balance but less than overall calcium balance, suggesting soft-tissue deposition. Fasting blood and urine biochemistries of calcium and phosphate homeostasis were unaffected by calcium carbonate. Thus, the positive calcium balance produced by calcium carbonate treatment within 3 weeks cautions against its use as a phosphate binder in patients with stage 3 or 4 CKD, if these findings can be extrapolated to long-term therapy.
Synthesis and oxidation reactions of cycloheptatrienyl sulfones

Abstract Inexpensive cycloheptatriene is regiospecifically converted to all three phenylsulfonyl substituted cycloheptatrienes. Epoxidation of these materials with achiral reagents is shown to be relatively regiospecific. Reasonable levels of enantiomeric excess (∼63,78%) are achieved by Sharpless asymmetric dihydroxylation of a pair of 3-substituted trienes. Crystallization of these sulfones provides the diols in enantiomeric excesses greater than 90%.
Strategic management and the internal organization of food marketing firms

Neoclassical and industrial organization economics have traditionally treated firm internal operations as a black box linking market structure to market performance. This approach is inadequate in our modern food distribution system where large firms shape markets as they are shaped by them. Given the importance of firm behavior to firm and market performance, major research is needed to develop a micro-microeconomic theory of the firm. Research on strategic choice by firms and their use of internal organization to implement those choices is a promising approach to developing this new theory.
Single neuron computation: From dynamical system to feature detector

White noise methods are a powerful tool for characterizing the computation performed by neural systems. These methods allow one to identify the feature or features that a neural system extracts from a complex input and to determine how these features are combined to drive the system's spiking response. These methods have also been applied to characterize the input-output relations of single neurons driven by synaptic inputs, simulated by direct current injection. To interpret the results of white noise analysis of single neurons, we would like to understand how the obtained feature space of a single neuron maps onto the biophysical properties of the membrane, in particular, the dynamics of ion channels. Here, through analysis of a simple dynamical model neuron, we draw explicit connections between the output of a white noise analysis and the underlying dynamical system. We find that under certain assumptions, the form of the relevant features is well defined by the parameters of the dynamical system. Further, we show that under some conditions, the feature space is spanned by the spike-triggered average and its successive order time derivatives.
Evaluation techniques for X-ray mirrors and systems using visible light

Severely diffraction-broadened visible light images from grazing incidence optical systems are measured and analyzed using a diffraction integral model to predict slope errors and image quality at XUV wavelengths.
Quasi steady-state model for power system stability: Limitations, analysis and a remedy

The quasi steady-state (QSS) model tries to reach a good compromise between accuracy and efficiency in long-term stability analysis. However, the QSS model is unable to provide correct approximations and stability assessment for the long-term stability model consistently. In this paper, some numerical examples in which the QSS model was stable while the long-term stability model underwent instabilities are presented with analysis in nonlinear system framework. At the same time, a hybrid model which serves as a remedy to the QSS model is proposed according to causes for failure of the QSS model and dynamic mechanisms of long-term instabilities. Numerical examples are given to show that the developed hybrid model can successfully capture unstable behaviors of the long-term stability model while the QSS model fails.
Phase structure of D-brane gauge theories and toric duality

Harnessing the unimodular degree of freedom in the definition of any toric diagram, we present a method of constructing inequivalent gauge theories which are world-volume theories of D-branes probing the same toric singularity. These theories are various phases in partial resolution of abelian orbifolds. As examples, two phases are constructed for both the zeroth Hirzebruch and the second del Pezzo surfaces. We show that such a phenomenon is a special case of ``Toric Duality'' proposed in hepth0003085. Furthermore, we investigate the general conditions that distinguish these different gauge theories with the same (toric) moduli space.
Mid-Infrared Laser Source with High Average Power and High Repetition Rate

An amplified passively Q-switched laser at 35kHz pumps an optical parametric generator to generate 1.5W around 1.5µm. Proper control of thermal lensing due to absorption of idler beam is critical for power scaling
Reliability considerations in switchable PLL frequency synthesizers for wireless sensor networks

In this work, reliability of communications systems in wireless sensor networks is addressed through the switchable phase-locked loops. The switchable phased-locked loop frequency synthesizer can work experimentally in a wide frequency range from 250 MHz to 700 MHz and is designed in 0.5μm n-well CMOS process. CMOS is the commonly used technology for communication systems wherein hot carrier injection and negative bias temperature instability are prime contributors to reliability. It is shown that both the hot carrier injection and negative bias temperature instability affect the performance of the phased-locked loop. The RMS jitter of the PLL increases by 40 ps and 23 ps for 4 hours of hot carrier injection and negative bias temperature instability stress, respectively. The experimental results show that the RMS jitter of the phase-locked loop varies from 30 ps to 123 ps as output frequency changes. The phase noise of phaselocked loop is -61 dBc/Hz at 10 kHz offset frequency and -104 dBc/Hz at 1 MHz offset frequency under 700 MHz phaselocked loop carrier frequency.
On Global Existence of 3D Charge Critical Dirac–Klein–Gordon System

In this paper, we prove the global well-posedness property of charge critical Dirac-Klein-Gordon (DKG) system in $\mathbb{R}^{3+1}$ for small initial data in a space of scale invariant data which has extra weighted regularity in the angular variables. Therefore, by finite speed propagation, we could also derive the local well-posedness property for large initial data in the same space. To author's knowledge, our result appears to be the first result on the critical 3D DKG.
Addition of 2,3-dihydro-5-furanyllithium to diisopropyl squarate as a means for the rapid generation of structurally complex oxygen-containing tetraquinane networks

Abstract The ability of 2,3-dihydro-5-furanyllithium (11) to trigger a reaction cascade when added to diisopropyl squarate (6) has been examined. Of particular concern were those experiments in which greater than 2 equiv of 11 were added to 6, as well when 1 equiv of 11 was added prior to or after an equiv of cyclopentenyllithium. The results shed light directly on such issues as whether the second vinyl anion adds cis or trans in reference to the first, and whether the bonding takes place in 1,2 or 1,4 fashion. Also revealed in the unsymmetrical case studies was whether protonation of the 1,3,5-cyclooctatriene intermediates occurs syn or anti to the adjacent proton and the extent to which this materialized at the “conventional” or the oxygen-substituted enolate site. In light of the fact that heterocyclic tetraquinanes containing five stereogenic centers are directly elaborated in one step from achiral building blocks, the transformations described in this work can be justifiably classified as “power reactions”.
Noisy heteroclinic networks

We consider a white noise perturbation of dynamics in the neighborhood of a heteroclinic network. We show that under the logarithmic time rescaling the diffusion converges in distribution in a special topology to a piecewise constant process that jumps between saddle points along the heteroclinic orbits of the network. We also obtain precise asymptotics for the exit measure for a domain containing the starting point of the diffusion.
Accounting for Skewness in Ensemble Data Assimilation

AbstractA practical data assimilation algorithm is presented that explicitly accounts for skewness in the prior distribution. The algorithm operates as a global solve (all observations are considered at once) using a minimization-based approach and Schur–Hadamard (elementwise) localization. The central feature of this technique is the squaring of the innovation and the ensemble perturbations so as to create an extended state space that accounts for the second, third, and fourth moments of the prior distribution. This new technique is illustrated in a simple scalar system as well as in a Boussinesq model configured to simulate nonlinearly evolving shear instabilities (Kelvin–Helmholtz waves). It is shown that an ensemble size of at least 100 members is needed to adequately resolve the third and fourth moments required for the algorithm. For ensembles of this size it is shown that this new technique is superior to a state-of-the-art ensemble Kalman filter in situations with significant skewness; otherwise, ...
Non-rocket Earth-Moon transport system

Abstract This paper proposes a new transportation system for travel between Earth and Moon. This transportation system uses mechanical energy transfer and requires only minimal energy, using an engine located on Earth. A cable directly connects a pole of the Earth through a drive station to the lunar surface_ The equation for an optimal equal stress cable for complex gravitational field of Earth-Moon has been derived that allows significantly lower cable masses. The required strength could be provided by cables constructed of carbon nanotubes or carbon whiskers. Some of the constraints on such a system are discussed.
Simulation of a piezoelectrically actuated valveless micropump

This paper numerically studies the performance of a piezoelectrically actuated valveless micropump with consideration of the three-way electro–mechanical–fluid couplings. Simulation of the piezoelectrically actuated valveless micropump (PVAM) indicates that both the pumping rate and the membrane deflection amplitude increase with the increase of the actuating frequency in a low frequency range ( 7.5 kHz). At even higher frequencies (>50 kHz), the pumping rate decreases further because the deflection amplitude decreases. This agrees with reported experimental results. The changing membrane deflection shapes at various frequencies clearly play an important role in the performance of the pump.
Cost scaling based successive approximation algorithm for the traffic assignment problem

Abstract This paper presents a cost scaling based successive approximation algorithm, called e -BA ( e -optimal bush algorithm), to solve the user equilibrium traffic assignment problem by successively refining e -optimal flows. As e reduces to zero, the user equilibrium solution is reached. The proposed method is a variant of bush-based algorithms, and also a variant of the min-mean cycle algorithm to solve the min-cost flow by successive approximation. In e -BA, the restricted master problem, implying traffic equilibration restricted on a bush, is solved to e -optimality by cost scaling before bush reconstruction. We show that e -BA can reduce the number of flow operations substantially in contrast to Dial’s Algorithm B, as the former operates flows on a set of deliberately selected cycles whose mean values are sufficiently small. Further, the bushes can be constructed effectively even if the restricted master problem is not solved to a high level of convergence, by leveraging the e -optimality condition. As a result, the algorithm can solve a highly precise solution with faster convergence on large-scale networks compared to our implementation of Dial’s Algorithm B.