cssi/SciSciGPT-SciSciNet huggingface dataset:
Lacrimal fluid and electrolyte secretion: A review

Lacrimal gland fluid is an important component of the precorneal tear film. The rate of lacrimal gland fluid secretion is controlled primarily by parasympathetic innervation, and it is, apparently, modulated by sympathetic innervation. Lacrimal gland fluid is produced in two stages, secretion of a primary fluid which resembles an isotonic ultrafiltrate of plasma in the acinus-early intercalated duct region, and secretion of a KCl-rich fluid in subsequent ductal elements. Little is known about the electrolyte transport mechanisms of the ductal epithelia. Recent work using a variety of techniques, including tracer flux measurements, intracellular electrical recording, intracellular ion activity measurements, patch clamping, and analytical subcellular fractionation, supports a model for transcellular Cl-secretion in the acinus which involves Cl--selective channels in the apical plasma membrane and an array of Na+/H+ antiporters, Cl-/HCO3-antiporters, K+ channels, and Na,K-ATPase in the basal-lateral plasma membrane.
Differences in the Usage of Bootstrap Financing among Technology‐Based versus Nontechnology‐Based Firms

This study compares owners’ assessment of the importance of 28 bootstrap financing methods between a sample of 44 technology-based and 44 nontechnology-based firms. The results indicated that owners’ of technology-based firms believed that 6 of the 28 bootstrap financing methods were more important as compared to owners’methods of nontechnology-based firms. The bootstrap financing methods also were grouped using Winborg and Landstrom (2001) factors. Owners of technology-based firms believed that bootstrap financing methods that improved cash inflows were more important and that bootstrap financing methods that slowed disbursements were less important compared to owners of nontechnology-based firms. The results can be used by owners of small firms, consultants and by support agencies that provide assistance with financial planning and capital acquisition. Understanding the use and availability of all sources of capital can help owners of small firms to develop comprehensive financial strategies. This information also could be incorporated into training programs for owners and managers of small firms.
On motivic decompositions arising from the method of Białynicki-Birula

Recently, V. Chernousov, S. Gille and A. Merkurjev have obtained a decomposition of the motive of an isotropic smooth projective homogeneous variety analogous to the Bruhat decomposition. Using the method of A. Bialynicki-Birula and a corollary, which is essentially due to S. del Bano, I generalize this decomposition to the case of a (possibly anisotropic) smooth projective variety homogeneous under the action of an isotropic reductive group. This answers a question of N. Karpenko.
Effects of MAC approaches on non-monotonic saturation with COPE - a simple case study

We construct a simple network model to provide insight into network design strategies. We show that the model can be used to address various approaches to network coding, MAC, and multi-packet reception so that their effects on network throughput can be evaluated. We consider several topology components which exhibit the same non-monotonic saturation behavior found within the Katti et. al. COPE experiments. We further show that fairness allocation by the MAC can seriously impact performance and cause this non-monotonic saturation. Using our model, we develop a MAC that provides monotonic saturation, higher saturation throughput gains and fairness among flows rather than nodes. The proposed model provides an estimate of the achievable gains for the cross-layer design of network coding, multi-packet reception, and MAC showing that super-additive throughput gains on the order of six times that of routing are possible.
Ammonium octahydrotriborate (NH4B3H8): new synthesis, structure, and hydrolytic hydrogen release.

A metathesis reaction between unsolvated NaB3H8 and NH4Cl provides a simple and high-yield synthesis of NH4B3H8. Structure determination through X-ray single crystal diffraction analysis reveals we...
Further observations on the Lewis acid-catalyzed benzylic hydroperoxide rearrangement: use of a boron-trifluoride/ hydrogen peroxide preformed, aged reagent

Abstract A preformed, aged reagent derived from boron trifluoride etherate and 90% hydrogen peroxide (2:1–4:1 complex) has been found to be a useful reagent for promoting the benzylic hydroperoxide rearrangement of readily oxidizable substrates bearing a free, basic amine. The use of this procedure for introduction of the C-4 phenol of the C-4/C-5 selectively-protected o -catechol unit found in PDE-I and PDE-II, naturally-occurring phosphodiesterase inhibitors constituting the central and right-hand segments of the antitumor-antibiotic CC-1065, is detailed.
Oxidative coupling of methane over calcium manganate and gadolinium manganate perovskites promoted with sodium pyrophosphate

Abstract GdMnO3, promoted with Na4P2O7 was found to be an active and selective catalyst for partial oxidation of methane to higher hydrocarbons. A C2-yield of 20% was obtained over this catalyst at 1101 K. There was no appreciable change in both the methane conversion and C2-yield during 26 h of reaction. CaMnO3 promoted with Na4P2O7 was found to be a poor catalyst for C2 formation even though both CaO and manganese oxide promoted with Na4P2O7 were good catalysts for the production of C2 compounds. An X-ray photoelectron spectroscopic analysis showed manganese in both Mn3+ and Mn4+ oxidation states was present on both Na4P2O7/GdMnO3 and Na4P2O7/ CaMnO3. Treatment of the catalyst Na4P2O7/GdMnO3 with helium improved both conversion and C2 selectivity. However, significant changes in the chemical states of sodium, manganese, and phosphorus were not observed on Na4P2O7/GdMnO3 after treating with helium. Thus, it was not feasible to relate the catalytic performance to the chemical states of different species present on the surface. Significant amounts of sodium were retained on the surface of Na4P2O7/GdMnO3 even after 20 h of reaction as observed by Auger electron spectroscopy. The perovskite structure did not affect the catalytic performance of CaMnO3 or GdMnO3 as evidenced by the fact that their respective oxide mixtures (CaO/manganese oxide and Gd2O3/manganese oxide) showed a similar catalytic activity.
The rise and fall of redundancy in decoherence and quantum Darwinism

A state selected at random from the Hilbert space of a many-body system is overwhelmingly likely to exhibit highly non-classical correlations. For these typical states, half of the environment must be measured by an observer to determine the state of a given subsystem. The objectivity of classical reality—the fact that multiple observers can agree on the state of a subsystem after measuring just a small fraction of its environment—implies that the correlations found in nature between macroscopic systems and their environments are exceptional. Building on previous studies of quantum Darwinism showing that highly redundant branching states are produced ubiquitously during pure decoherence, we examine the conditions needed for the creation of branching states and study their demise through many-body interactions. We show that even constrained dynamics can suppress redundancy to the values typical of random states on relaxation timescales, and prove that these results hold exactly in the thermodynamic limit.
Synthesis of the individual enantiomers of the benzoquinolinone human type 1 steroid 5-α-reductase inhibitors LY191704 and LY266111

Abstract The first syntheses of the individual enantiomers of the benzoquinolinone class of selective inhibitors of human Type 1 steroid 5-α-reductase are described. For benzoquinolinones lacking an angular substituent, the approach relies upon an enamine acryloyl chloride cyclization followed by non-stereoselective reduction and diastereomer separation. Absolute configuration was established by single crystal x-ray diffraction analysis. The angularly methylated benzoquinolinones are prepared in an enantiospecific (deracemizing) fashion from 1-methyl-6-chloro-2-tetralone in 5 steps, employing a “formal 3 + 3 aza-annulation” sequence, with (R) or (S) α-phenethylamine as the source of chirality.
On the interlace polynomials

The generating function that records the sizes of directed circuit partitions of a connected 2-in, 2-out digraph D can be determined from the interlacement graph of D with respect to a directed Euler circuit; the same is true of the generating functions for other kinds of circuit partitions. The interlace polynomials of Arratia, Bollobas and Sorkin [R. Arratia, B. Bollobas, G.B. Sorkin, The interlace polynomial of a graph, J. Combin. Theory Ser. B 92 (2004) 199-233; R. Arratia, B. Bollobas, G.B. Sorkin, A two-variable interlace polynomial, Combinatorica 24 (2004) 567-584] extend the corresponding functions from interlacement graphs to arbitrary graphs. We introduce a multivariate interlace polynomial that is an analogous extension of a multivariate generating function for undirected circuit partitions of undirected 4-regular graphs. The multivariate polynomial incorporates several different interlace polynomials that have been studied by different authors, and its properties include invariance under a refined version of local complementation and a simple recursive definition.
The Logic of Rational Play in Games of Perfect Information

For the past 20 years or so the literature on noncooperative games has been centered on the search for an equilibrium concept that expresses the notion of rational behavior in interactive situations. A basic tenet in this literature is that if a “rational solution” exists, it must be a Nash equilibrium. The consensus view, however, is that not all Nash equilibria can be accepted as rational solutions. Consider, for example, the game of Figure 1.
Transition State Structure for the Water-Catalyzed Hydrolysis of p-Nitrophenyl Trifluoroacetate in Acetonitrile.

The neutral hydrolysis of p-nitrophenyl trifluoroacetate in acetonitrile solvent has been studied by varying the molarities of water from 1.0 to 5.0 at 25 °C. The reaction is found to be third order in water. The reaction is also third order in D2O and in methanol when D2O and methanol replace water as the solvent. The kinetic solvent isotope effect is (kH2O/kD2O) = 2.90 ± 0.12. Proton inventories at each molarity of water studied are consistent with an eight-membered cyclic transition state model. In this model, three protons undergo bonding changes. Such an eight-membered transition state model can easily accommodate linear hydrogen bonds for the three transferred protons. These results are consistent with the experimental findings of Bell and Critchlow1 on the reversible addition of water to 1,3-dichloroacetone in dioxane and the theoretical findings of Wolfe and co-workers2 on the hydration of formaldehyde.
Mobility label based network: Hierarchical mobility management and packet forwarding architecture

Scalability of the network layer mobility management solution is one of the most important requirements for the mobility control plane. Mobility Label Based Network (MLBN) is a new approach to the network layer mobility management problem that relies solely on MPLS to provide both macro- and micro-mobility for IPv4 and IPv6 mobile hosts and routers. This new approach does not rely on the existing IP mobility management protocols such as Mobile IP and is based on the combination of Multi-Protocol BGP (MP-BGP) and MPLS. In the context of the MLBN the scalable control plane should be capable of efficient Mobility Label distribution while allowing the MPLS-based forwarding plane to deliver mobile traffic in an optimal manner. This paper presents a hierarchical mobility management system capable of both macro- and micro-mobility support without the use of Mobile IP and its derivatives and allows scalable Mobility Label distribution and MPLS label stack based packet forwarding in support of optimal traffic delivery between the communicating mobile users.
CONSTRAINTS ON THE LOW-MASS END OF THE MASS-METALLICITY RELATION AT z = 1-2 FROM LENSED GALAXIES

We present multi-wavelength imaging and near-IR spectroscopy for 10 gravitationally lensed galaxies at 0.9 < z < 2.5 selected from a new, large sample of strong lens systems in the Sloan Digital Sky Survey Data Release 7. We derive stellar masses from the rest-frame UV to near-IR spectral energy distributions, star formation rates (SFRs) from the dust-corrected Hα flux, and metallicities from the [N II]/Hα flux ratio. We combine the lensed galaxies with a sample of 60 star-forming galaxies from the literature in the same redshift range for which measurements of [N II]/Hα have been published. Due to the lensing magnification, the lensed galaxies probe intrinsic stellar masses that are on average a factor of 11 lower than have been studied so far at these redshifts. They have specific SFRs that are an order of magnitude higher than seen for main-sequence star-forming galaxies at z ~ 2. We measure an evolution of 0.16 ± 0.06 dex in the mass-metallicity relation between z ~ 1.4 and z ~ 2.2. In contrast to previous claims, the redshift evolution is smaller at low stellar masses. We do not see a correlation between metallicity and SFR at fixed stellar mass. The combined sample is in general agreement with the local fundamental relation between metallicity, stellar mass, and SFR from Mannucci et al. Using the Kennicutt-Schmidt law to infer gas fractions, we investigate the importance of gas inflows and outflows on the shape of the mass-metallicity relation using simple analytical models. This suggests that the Maiolino et al. calibration of the [N II]/Hα flux ratio is biased high.
Total synthesis of (+)-camptothecin

A total synthesis of (+)-camptothecin is described. The approach is based on a room temperature LUMOdiene-controlled Diels–Alder cycloaddition of the electron deficient N-sulfonyl-1-aza-1,3-butadiene 6 with the electron rich dienophile 1,1,3,3-tetraethoxypropene (7) for assembly of a pyridine precursor to the D-ring pyridone. The 20(S) tertiary alcohol was installed through a Sharpless asymmetric dihydroxylation reaction on the methyl vinyl ether 12, using the 3,4,5-trimethoxyphenyl-derived pyrimidine DHQ dimer ligand 16. In a single reaction vessel, the C and E rings were closed using an acid-catalyzed deprotection of the benzylic ethers to afford the corresponding benzylic bromides (18) which underwent intramolecular nucleophilic displacement by the carboxylate and pyridone nitrogen to furnish (+)-camptothecin.
Portfolio risk and self‐directed retirement saving programmes*

Defined contribution retirement plans expose retirement savers to financial market risks. This paper explores the costs of retirement wealth risk. It begins by describing the holding of company stock in 401(k) plans in the US, an investment choice that yields a poorly diversified retirement portfolio. It then summarises the composition of household wealth at retirement and investigates how the degree of diversification in retirement assets affects expected utility. The cost of holding a poorly diversified retirement portfolio is very sensitive to whether or not the retirement saver has other assets that provide a floor for retirement consumption.
Germline mosaicism of PHOX2B mutation accounts for familial recurrence of congenital central hypoventilation syndrome (CCHS).

Congenital central hypoventilation syndrome (CCHS), a rare disorder characterized by alveolar hypoventilation and autonomic dysregulation, is caused by mutations in the PHOX2B gene. Most mutations occur de novo, but recent evidence suggests that up to 25% are inherited from asymptomatic parents with somatic mosaicism for these mutations. However, to date, germline mosaicism has not been reported. This report describes a family with recurrence of PHOX2B mutation-confirmed CCHS due to germline mosaicism. The first occurrence was a baby girl, noted on day 2 of life to have multiple episodes of apnea, bradycardia, and cyanosis while breathing room air. PHOX2B gene testing confirmed the diagnosis of CCHS with a heterozygous polyalanine repeat expansion mutation (PARM); genotype 20/27 (normal 20/20). Both parents tested negative for this mutation using fragment analysis (limit of detection <1%). Upon subsequent pregnancy [paternity confirmed using short tandem repeat (STR) analysis], amniocentesis testing identified the PHOX2B 20/27 genotype, confirmed with repeat testing. Elective abortion was performed at 21.5 weeks gestation. Testing of abortus tissue confirmed amniocentesis testing. The PHOX2B 20/27 expansion was not observed in a paternal sperm sample. This case represents the first reported family with recurrence of PHOX2B mutation-confirmed CCHS without detection of a parental carrier state or mosaicism, confirming the previously hypothesized possibility of germline mosaicism for PHOX2B mutations. This is an important finding for genetic counseling of CCHS families, suggesting that even if somatic mosaicism is not detected in parental samples, there is still reason for careful genetic counseling and consideration of prenatal testing during subsequent pregnancies. © 2012 Wiley Periodicals, Inc.
ALE Ricci-flat Kähler surfaces and weighted projective spaces

We show that the explicit ALE Ricci-flat Kahler metrics constructed by Eguchi–Hanson, Gibbons–Hawking, Hitchin and Kronheimer, and their free quotients are metrics obtained by Tian–Yau techniques. The proof relies on a construction of good compactifications of \(\mathbb {Q}\)-Gorenstein deformations of quotient surface singularities as log del Pezzo surfaces with only cyclic quotient singularities at infinity.
Reverse importing and asymmetric trade and FDI: a networks explanation

Abstract This paper considers the impact of business and social networks on international trade and FDI. I propose that differences in the strength of network effects across countries can produce asymmetric trade and investment flows that may lead to trade friction. A firm from a country with strong network effects has a cost advantage in selling to buyers from its own country. This advantage results in lower inward FDI, lower total imports but larger volumes of reverse imports into the country with strong network effects. The model’s predictions match observed asymmetric trade and investment flows that sometimes lead to US–Japan trade friction.
Entanglement's benefit survives an entanglement-breaking channel.

Entanglement is essential to many quantum information applications, but it is easily destroyed by quantum decoherence arising from interaction with the environment. We report the first experimental demonstration of an entanglement-based protocol that is resilient to loss and noise which destroy entanglement. Specifically, despite channel noise 8.3 dB beyond the threshold for entanglement breaking, eavesdropping-immune communication is achieved between Alice and Bob when an entangled source is used, but no such immunity is obtainable when their source is classical. The results prove that entanglement can be utilized beneficially in lossy and noisy situations, i.e., in practical scenarios.
Interactions in the labial musculature during speech.

Interactions in electromyographic activity of the upper and lower lips during speech were studied by manipulating the magnitude of bursts of activity related to bilabial closure. Four pairs of elec...
NUMERICAL STUDY OF TURBULENT MIXING LAYERS WITH NON-EQUILIBRIUM IONIZATION CALCULATIONS

Highly ionized species, such as C IV, N V, and O VI, are commonly observed in diffuse gas in various places in the universe, such as in our Galaxy's disk and halo, high velocity clouds (HVCs), external galaxies, and the intergalactic medium. These ions are often used to trace hot gas whose temperature is a few times 105 K. One possible mechanism for producing high ions is turbulent mixing of cool gas (such as that in a high or intermediate velocity cloud) with hotter (a few times 106 K) gas in locations where these gases slide past each other. By using hydrodynamic simulations with radiative cooling and non-equilibrium ionization (NEI) calculations, we investigate the physical properties of turbulent mixing layers and the production of high ions (C IV, N V, and O VI). We find that most of the mixing occurs on the hot side of the hot/cool interface, where denser cool gas is entrained and mixed into the hotter, more diffuse gas. Our simulations reveal that the mixed region separates into a tepid zone containing radiatively cooled, C IV-rich gas and a hotter zone which is rich in C IV, N V, and O VI. The hotter zone contains a mixture of low and intermediate ions contributed by the cool gas and intermediate and high-stage ions contributed by the hot gas. Mixing occurs faster than ionization or recombination, making the mixed gas a better source of C IV, N V, and O VI in our NEI simulations than in our collisional ionization equilibrium (CIE) simulations. In addition, the gas radiatively cools faster than the ions recombine, which also allows large numbers of C IV, N V, and O VI ions to linger in the NEI simulations. For these reasons, our NEI calculations predict more C IV, N V, and O VI than our CIE calculations predict. We also simulate various initial configurations and find that more C IV is produced when the shear speed is smaller or the hot gas has a higher temperature. We find no significant differences between simulations having different perturbation amplitudes in the initial boundary between the hot and cool gas. We discuss the results of our simulations, compare them with observations of the Galactic halo and highly ionized HVCs, and compare them with other models, including other turbulent mixing calculations. The ratios of C IV to N V and N V to O VI are in reasonable agreement with the averages calculated from observations of the halo. There is a great deal of variation from sightline to sightline and with time in our simulations. Such spatial and temporal variation may explain some of the variation seen among observations.
The status of GMSB after 1/fb at the LHC

We thoroughly investigate the current status of supersymmetry in light of the latest searches at the LHC, using General Gauge Mediation (GGM) as a well-motivated signature generator that leads to many dierent simplied models. We consider all possible promptly-decaying NLSPs in GGM, and by carefully reinterpreting the existing LHC searches, we derive limits on both colored and electroweak SUSY production. Overall, the coverage of GGM parameter space is quite good, but much discovery potential still remains even at 7 TeV. We identify several regions of parameter space where the current searches are the weakest, typically in models with electroweak production, third generation sfermions or squeezed spectra, and we suggest how ATLAS and CMS might modify their search strategies given the understanding of GMSB at 1/fb. In particular, we propose the use of leptonic MT 2 to suppress tt backgrounds. Because we express our results in terms of simplied models, they have broader applicability beyond the GGM framework, and give a global view of the current LHC reach. Our results on 3rd generation squark NLSPs in particular can be viewed as setting direct limits on naturalness.
The angular momentum of the Oort cloud

An evaluation is made of the work of Marochnik et al. (1988), which estimated that the angular momentum of the Oort cloud is 2-3 orders of magnitude greater than the planetary system's total angular momentum. It is noted that most of the angular momentum in the currently observed Oort cloud is the result of the effects of external perturbers over the solar system's history, and it is demonstrated that the total current angular momentum is probably in the 6.0 x 10 to the 50th to 1.1 x 10 to the 51st g sq cm/sec range; original angular momentum was probably a factor of 5 below such values.
Mitochondrial viability in mouse and human postmortem brain

Neuronal function in the brain requires energy in the form of ATP, and mitochondria are canonically associated with ATP production in neurons. The electrochemical gradient, which underlies the mitochondrial transmembrane potential (ΔΨmem), is harnessed for ATP generation. Here we show that ΔΨmem and ATP-production can be engaged in mitochondria isolated from human brains up to 8.5 h postmortem. Also, a time course of postmortem intervals from 0 to 24 h using mitochondria isolated from mouse cortex reveals that ΔΨmem in mitochondria can be reconstituted beyond 10 h postmortem. It was found that complex I of the mitochondrial electron transport chain was affected adversely with increasing postmortem intervals. Mitochondria isolated from postmortem mouse brains maintain the ability to produce ATP, but rates of production decreased with longer postmortem intervals. Furthermore, we show that postmortem brain mitochondria retain their ΔΨmem and ATP-production capacities following cryopreservation. Our finding t...
Palladium-Catalyzed α-Arylation of Benzylic Phosphonates

A new synthetic route to access diarylmethyl phosphonates is presented. The transformation enables the introduction of aromatic groups on benzylic phosphonates via a deprotonative cross-coupling process (DCCP). The Pd(OAc)2/CataCXium A-based catalyst afforded a reaction between benzyl diisopropyl phosphonate derivatives and aryl bromides in good to excellent isolated yields (64–92%).
Astrophysics and cosmology confront the 17-keV neutrino.

A host of astrophysical and cosmological arguments severely constrain the properties of a 17 keV Dirac neutrino. Such a neutrino must have interactions beyond those of the standard electroweak theory to reduce its cosmic abundance (through decay or annihilation) by a factor of two hundred. A predicament arises because the additional helicity states of the neutrino necessary to construct a Dirac mass must have interactions strong enough to evade the astrophysical bound from SN 1987A, but weak enough to avoid violating the bound from primordial nucleosynthesis.
Quasi-isentropic material property studies at extreme pressures: from Omega to NIF

We are developing an experimental platform that can compress materials quasi-isentropically to very high pressures at ultrahigh strain rates. This laser driven, ramped (shockless) drive is used to study material properties such as strength, equation of state, phase, and phase transition kinetics under extreme conditions. We have achieved a ramped, shockless drive up to 2 Mbar on the Omega laser using both direct laser illumination and indirect x-ray illumination. In order to probe high-Z materials under extreme pressures, we are also developing high energy x-ray backlighters, 17 to 100 keV, created by high intensity (>1018 W/cm2) short pulse lasers (1 to 50 ps) such as the Titan laser at LLNL. Using a micro-wire embedded in a low-Z substrate, we have obtained radiographs with better than 10 ?m spatial resolution. This paper will show designs of isentropic platforms that can reach >10 Mbar on the NIF laser, using both direct and indirect drive configurations.
Current Resources for Evidence‐Based Practice, September/October 2015

Standardizing Evidence-Based Perinatal Practice Amid the Medical Malpractice Threat I recently had a conversation with a fellow midwife in which she discussed a frustrating encounter she had with a collaborating physician regarding her care of a woman receiving labor augmentation for premature rupture of membranes. The physician was concerned about the woman’s rate of cervical dilation and expressed his opinion that she should have a cesarean if she did not give birth vaginally in the next few hours. The midwife cited a recent obstetric care consensus (American College of Obstetricians and Gynecologists & Society for Maternal-Fetal Medicine, 2014) as evidence to support her recommendation that the woman have more time to complete latent-phase labor in the presence of normal maternal and fetal monitoring results. The physician was dismissive of this evidence and told the midwife, “No new study or guideline is going to save us if anything goes wrong with this baby. I’m not risking a medical malpractice case over this.” Later, the midwife was pessimistic about evidence-based practice as she discussed the conversation with me, “Does it even matter if we have scientific evidence about clinical practice, when the only thing guiding our decision making is the fear of a medical malpractice claim?”
FROM SELF-SIMILAR STRUCTURES TO SELF-SIMILAR GROUPS

We explore the relationship between the limit spaces of contracting self-similar groups and self-similar structures. We give the condition on a contracting group such that its limit space admits a self-similar structure, and also the condition such that this self-similar structure is post-critically finite (p.c.f.). We then give necessary and sufficient conditions for a p.c.f. self-similar structure to be the limit space of a contracting self-similar group. When these conditions hold we give a construction of the contracting group. Finally, we illustrate our results with several examples.
Combined Numerical and Experimental Investigation of a Hobby-Scale Pulsejet

The pulsejet, due to its simplicity, may be an ideal micro propulsion system, but has received very little attention since the mid 1950’s. Here, modern computational and experimental tools are used to investigate the operation of a hobby scale (50 cm overall length) pulsejet. Gas dynamics, acoustics and chemical kinetics are all involved and are studied to gain an understanding of the various physical phenomena affecting pulsejet operation, scaleability and efficiency. A Bailey Machining Service (BMS) hobby pulsejet is instrumented to obtain pressure, temperature, thrust, and frequency. CH * chemiluminescence is utilized to determine combustion time and high speed imaging of the reed valve operation is undertaken to determine the valve duty cycle. Laser Doppler Velocimetry (LDV) has been used to measure the instantaneous exhaust velocity in these unsteady combustion devices. Numerical simulations are performed utilizing CFX to model the 3-D compressible vicious flow in the pulsejet using the integrated Westbrook-Dryer single step combustion model. The turbulent flow and reaction rate are modeled with the ke model and the Eddy Dissipation Model (EDM), respectively. Simulation results provide physical insight into the pulsejet cycle; comparisons with experimental data obtained in this research are carried out. The traditional view of a pulsejet as a 1/4 wave tube operating on the Humphrey cycle is modified with to account for valve operation and finite chemical kinetics.
Power Optimization and Control in Wind Energy Conversion Systems Using Extremum Seeking

Power optimization and control for grid-coupled wind energy conversion systems (WECS) has been extensively studied for variable speed wind turbines. However, existing methods widely use model-based power optimization algorithms in the outer loop along with linear control techniques in the inner loop. The transient performance of this combination is dependent on the system's operating point, especially under fast varying wind regimes. We employ extremum seeking (ES) in the outer loop, which is a nonmodel-based optimization approach, to perform maximum power point tracking, i.e., extract maximum power from WECS in their subrated power region. Since the convergence rate of the ES design may be limited by the speed of the system dynamics, we also design a nonlinear controller, based on the field-oriented control concept and feedback linearization, that yields improvement in convergence rate by two orders of magnitude. The outer ES loop tunes the turbine speed to maximize power capture for all wind speeds within the subrated power operating conditions. The inner-loop nonlinear control maintains fast transient response through a matrix converter, by regulating the electrical frequency and voltage amplitude of the stator of the (squirrel-cage) induction generator. Simulation results are presented to show the effectiveness of the proposed design.
A Modal Analysis of Lamellar Diffraction Gratings in Conical Mountings

Abstract A rigorous modal analysis of lamellar gratings, i.e. gratings having rectangular grooves, in conical mountings is presented. It is an extension of the analysis of Botten et al. which considered non-conical mountings. A key step in the extension is a decomposition of the electromagnetic field in the grating region into two orthogonal components. A computer program implementing this extended modal analysis is capable of dealing with plane wave diffraction by dielectric and metallic gratings with deep grooves, at arbitrary angles of incidence, and having arbitrary incident polarizations. Some numerical examples are included.
A matching pursuit approach to solenoidal filtering of three-dimensional velocity measurements

Methodologies to acquire three-dimensional velocity fields are becoming increasingly available, generating large datasets of steady state and transient flows of engineering and/or biomedical interest. This paper presents a novel linear filter for three-dimensional velocity acquisitions, which eliminates the spurious velocity divergence due to measurement errors. The noise reduction properties of the associated linear operator are discussed together with the treatment of boundary conditions and efficient handling of large measurement datasets. Examples show the application of the technique to real velocity fields acquired through Magnetic Resonance Velocimetry as well as Particle Image Velocimetry. The effectiveness of the filter is demonstrated by application to synthetic velocity fields obtained from analytical solutions and computations. The filter eliminates about half of the noise, without artificial smoothing of the original data, and conserves localized flow features.
A continuous-time formulation of nonlinear model predictive control

A model predictive approach is used to derive a continuous-time, nonlinear feedback control law for open-loop stable, single-input single-output processes with deadtime. The derived model predictive control law minimizes a quadratic performance index in the presence of input constraints and process deadtime. A key feature of the control law is that, for its implementation, one does not need to perform an online optimization. In the absence of constraints, the control law in special cases is identical to the feedback controllers that have already been derived using a geometric approach. The connections between the derived control law and (a) the globally linearizing control and (b) the linear internal model control are established. The model predictive approach provides some insight into the problem of constraint handling in geometric control methods. The application of the theory is illustrated by a chemical reactor example.
Effect of Hydrocortisone Dose Schedule on Adrenal Steroid Secretion in Congenital Adrenal Hyperplasia

To explore the potential effect of dose schedule on the adrenal suppressive action of hydrocortisone in congenital adrenal hyperplasia, eight patients (six with 21-hydroxylase deficiency and two with 11-hydroxylase deficiency) were given five different dose schedules. Two of the schedules used single daily doses (morning or evening), two twice daily doses (two-thirds dose in the morning or evening), one and three equal doses at morning, noon, and night. Each dose schedule used the same total daily hydrocortisone dose (12.5 mg/m2/day), which is within the normal range of hydrocortisone production rate. Each schedule was given for 4 to 6 weeks. The different dose schedules caused the predicted alterations in the temporal pattern of adrenal steroid levels, with the greatest apparent suppression during the 2 to 4 hours after each dose. None of the schedules, however, caused significant differences in the mean 24-hour plasma concentration of 17-hydroxyprogesterone (21-hydroxylase deficiency) or 11-deoxycortisol (11-hydroxylase deficiency) or in the 24-hour urine pregnanetriol or 17-ketosteroid concentrations, either in the six patients undertreated at the dose of 12.5 mg/m2/day or in the two patients adequately treated. Nocturnal administration of all or a part of the daily dose did not improve adrenal suppression. These observations suggest that treatment of congenital adrenal hyperplasia with a once-a-day hydrocortisone dose schedule may be as effective as conventional multiple-dose schedules. Until this hypothesis has been tested by more extended clinical studies, however, we do not recommend a once-a-day schedule. Regardless of the dose schedule, the total daily hydrocortisone dose must be adjusted to achieve a normal rate of growth and bone age advancement.
A generalized model of mutation--selection balance with applications to aging

A probability model is presented for the dynamics of mutation-selection balance in a haploid infinite-population infinite-sites setting sufficiently general to cover mutation-driven changes in full age-specific demographic schedules. The model accommodates epistatic as well as additive selective costs. Closed form characterizations are obtained for solutions in finite time, along with proofs of convergence to stationary distributions and a proof of the uniqueness of solutions in a restricted case. Examples are given of applications to the biodemography of aging.
Plasma waves in the polar cusp: Observations from Hawkeye 1

Based on data from the Hawkeye 1 spacecraft in the polar-cusp vicinity, the characteristics of plasma waves are studied. Four types of plasma waves are identified: (1) a band of ULF-ELF magnetic noise, (2) broadband electrostatic emissions with maximum intensities at 10-50 Hz, (3) electrostatic electron cyclotron waves near electron gyrofrequency, and (4) whistler mode auroral hiss emissions. Only ULF-ELF noise is a reliable index of the polar cusp region. Since ULF-ELF magnetic noise extends only to the local electron gyrofrequency, it is suggested that the noise consists of whistler-mode electromagnetic waves. Possible mechanisms for this noise include the whistler-mode cyclotron-resonance, Kelvin-Helmholtz, and drift-wave instabilities. It is felt that a current-driven electrostatic instability causes the broadband electrostatic noise.
Two-level domain decomposition preconditioning for the p-version finite element method in three dimensions

This paper presents a flexible approach to domain decomposition preconditioning for problems expressed in terms of local stiffness matrices of subdomains. Evaluation of the preconditioner requires fully parallelizable local computations and the solution of a global auxiliary problem with few variables per subdomain. Convergence factors can be bounded using properties of the local stiffness matrices only. The method is applied to the p-version finite element method for three-dimensional elasticity. We treat each element as a subdomain and compute explicit convergence bounds.
Generalized path expressions: a high level debugging mechanism

This paper introduces a modified version of path expressions called Path Rules which can be used as a debugging mechanism to monitor the dynamic behaviour of a computation. Path rules have been implemented in a remote symbolic debugger running on the Three Rivers Computer Corporation PERQ computer under the Accent operating system.
Electron transport in very clean, as-grown suspended carbon nanotubes

Single-walled carbon nanotubes have shown a wealth of quantum transport phenomena thus far1,2,3,4,5,6,7,8,9,10,11. Defect-free, unperturbed single-walled carbon nanotubes with well behaved or tunable metal contacts are important for probing the intrinsic electrical properties of nanotubes. Meeting these conditions experimentally is non-trivial owing to numerous disorder and randomizing factors. Here we show that ∼1-μm-long fully suspended single-walled carbon nanotubes grown in place between metal contacts afford devices with well defined characteristics over much wider energy ranges than nanotubes pinned on substrates. Various low-temperature transport regimes in true-metallic, small- and large-bandgap semiconducting nanotubes are observed, including quantum states shell-filling, -splitting and -crossing in magnetic fields owing to the Aharonov–Bohm effect. The clean transport data show a correlation between the contact junction resistance and the various transport regimes in single-walled-carbon-nanotube devices. Furthermore, we show that electrical transport data can be used to probe the band structures of nanotubes, including nonlinear band dispersion.
Managerial ownership and the role of privatization in transition economies: The case of China

Within transition economies, a popular tactic for revitalizing large and inefficient stateowned enterprises (SOEs) is to privatize them. Unfortunately, the empirical evidence related to this issue is equivocal. This study, therefore, explores more deeply what the relationship may be between privatization efforts of SOEs and their financial performance in transition economies. Specifically, we seek to better understand whether privatization reforms per se, or other corporate governance mechanisms that complement or substitute for this effort, are most effective. Using a panel sample of Chinese state-owned public firms over an eight year period from 1999 to 2006, we find that managerial ownership has a more significant impact on firm performance than privatization does. This finding suggests that internal incentives to managers may be more effective than external market mechanisms in economies transitioning from centralized planning to market control. Our results are robust using a wide variety of performance measures and different model specifications.
Telemedicine screening for eye disease.

Telemedicine is increasinglyused fordiseasemonitoringandmanagement of chronic medical and mental disorders, but also has screening and diagnostic applications such as teleradiology and teledermatology. Indeed, “therapy at a distance” will complement office-based care in the 21st century. Another screening application is teleophthalmology, in which digital photography with telemedicine links has proven cost-effective for retinal disorders, including diabetic retinopathy and retinopathy of prematurity.1,2 Ina recent study in JAMAOphthalmology, Chasanetal3 complementedpriorcost-effectivenessanalysesof teleretinal screeningprogramsbyexaminingboth theaccuracyofdiabetic teleretinal screening as well as the subsequent eye care use and resources required in such a program. Regarding accuracy, screening tests that have good sensitivity and specificity are likely to bemore cost-effective. Regarding resource use, implementation of screening generates more referrals, testing, and procedures. The cost-effectiveness of any screening program is therefore contingent on reasonable test accuracy coupledwith a sufficient supply of resources tomeet the increased demand. Chasan et al3 conducted the study in community-based clinics ofasingleVeteransAffairs (VA)medical center.Of 1935patientswho underwent diabetic retinal screening, 465 (24%) had an abnormal finding on the retinal photograph and were referred to the VA eye clinic, of whom 326 were seen by an eye specialist and had a confirmatorydiagnosis.Themostcommonreasonsfor referralwerenonmacular diabetic retinopathy (43.2%), nerve-related disease (30.8%), lensormediaopacity (19.1%), age-relatedmacular degeneration (12.9%), and diabetic macular edema (5.6%). The percentageof agreementbetween retinal screeningand theophthalmicexamination for all diagnoseswas 90.4%,with a sensitivity of 73.6%. Sensitivity may have been somewhat inflated for 2 reasons. First, onlypatientswithabnormal retinalphotographswere referred, thus greatly increasing the number of cases with disease and minimizing thenumberof caseswithoutdisease. This verificationbias (also known as “workup bias” or “referral bias”) is a type of measurementbias inwhich the resultsof adiagnostic test affectwhether the gold standard procedure is used to verify the test result. Second, it is not clear that the clinician performing the ophthalmic examinaJAMAOPHTHALMOLOGY
The perturbative QCD factorization approach in high energy nuclear collisions

I discuss the systematic modifications to the perturbative QCD factorization approach in high energy l + A, p + A and A + A reactions. These include transverse momentum diffusion manifest in the Cronin effect and a small increase in the dijet acoplanarity; nuclear size enhanced power corrections that lead to shadowing in deeply inelastic scattering and suppression of single and double inclusive hadron production at forward rapidity at RHIC but disappear as a function of the transverse momentum; inelastic attenuation of the jet cross sections or jet quenching that persists to much higher pT.
Spectral theory, Hausdorff dimension and the topology of hyperbolic 3-manifolds

Let M be a compact 3-manifold whose interior admits a complete hyperbolic structure. We let Λ(M) be the supremum of λ0(N) where N varies over all hyperbolic 3-manifolds homeomorphic to the interior of N. Similarly, we let D(M) be the infimum of the Hausdorff dimensions of limit sets of Kleinian groups whose quotients are homeomorphic to the interior of M. We observe that A(M) = D(M)(2 − D(M)) if M is not handlebody or a thickened torus. We characterize exactly when A(M) = 1 and D(M) = 1 in terms of the characteristic submanifold of the incompressible core of M.
The 1961 JPL Venus Radar Experiment

The feasibility of exploring the solar system by radar was demonstrated on March 10, 1961, when a radio signal was beamed at the planet Venus, and for the first time in history the return echo was detected within a few minutes. The JPL Venus radar experiment has resulted in 1) an improvement of the accuracy of the Astronomical Unit by more than two orders of magnitude, 2) a determination that the dielectric constant and apparent roughness of its surface material are not unlike surface materials commonly found on Earth, and 3) a determination of the rotation rate of Venus for its most probable axis of rotation. In addition, the experiment verified that reliable interplanetary UHF communication is possible over ranges of 50 to 75 million miles and that planetary radar observatories are both practical and useful. Many improvements in the state of the radar and communications art are noted.
Topological obstructions to nonnegative curvature

We find new obstructions to the existence of complete Riemannian metric of nonnegative sectional curvature on manifolds with infinite fundamental groups. In particular, we construct many examples of vector bundles whose total spaces admit no nonnegatively curved metrics.
An Investigation on Information and Gender-Based Power in Product Design Decision-Making

The goal of the designed experiment and subsequent analyses presented in this paper was to investigate the power distributions especially with regards to gender in mixed-gender groups engaged in product design decision-making. The task involved determining the set of design criteria pertaining to consumer products with varying gender orientations, and rating the criteria for their importance according to various stakeholder interests. Results indicate that group level acceptance of the contributions was indeed impacted by the type of the product that the decision-making focused on, and that this impact can be attributed to the perceived knowledge levels of the individuals due to their expected familiarity with the product.