cssi/SciSciGPT-SciSciNet huggingface dataset:
Comparative study of two-membrane permeators for gas separations

Abstract The performance of several two-membrane permeation systems, including a two-membrane permeator (TMP), a two-membrane series-type permeator (TMS), and a two-membrane column (TMC), were studied. The product composition and the extent of separation were compared. The membrane area requirements for given product purity and stage cuts were also examined. The separation of air with membranes having hypothetical selectivities of 10 and 0.1 was used as an illustrating example, while the separation of a helium-oxygen mixture with actually available membranes was used as a practical application. From the results it was concluded that when a high-purity A-enriched product is desired from a gas mixture of components A and B, the TMS with an A-permeable membrane in the first stage is the most efficient arrangement. When a moderate-purity A-enriched product is desired, the TMS with a B-permeable membrane in the first stage or a TMP arrangement is preferable. The TMS performance can be further improved by recycling the reject stream. Only minimal improvement in separation by recycling can be expected in the TMP design.
Pressure dependence of the reaction of chlorine atoms with ethene and acetylene in air at 295 K

The relative rate technique has been used to determine rate constants for the reaction of chlorine atoms with ethene and acetylene over the pressure ranges 10-3,000 and 10-5,800 Torr, respectively, of synthetic air at 295 K. The decays of the reactants were measured relative to that of either ethane or chloroethane or both. Using a pressure-independent value of 5.7 {times} 10{sup {minus}11} cm{sup 3} molecule{sup {minus}1} s{sup {minus}1} for the reaction of Cl with ethane, the relative data were placed on an absolute basis and fit to the Troe expression with the broadening factor, F, fixed at 0.6. Values of the best-fit low-pressure termolecular rate constant, k{sub 0}, and high-pressure limiting bimolecular rate constant, k{sub {infinity}}, for the reaction of Cl atoms with ethene were k{sub 01} = 1.6 {sub {minus}0.3}{sup +1} {times} 10{sup {minus}29} cm{sup 6} molecule{sup {minus}2} s{sup {minus}1} and k{sub {infinity}1} = 3.05{sub {minus}0.4}{sup +2} {times} 10{sup {minus}10} cm{sup 3} molecule{sup {minus}1} s{sup {minus}1}, and those for the reaction of Cl atoms with acetylene were k{sub 02} = (5.2 {plus minus} 0.7) {times} 10{sup {minus}30} cm{sup 6} molecule{sup {minus}2} s{sup {minus}1} and k{sub {infinity}2} = (2.3 {plus minus} 0.7) {times} 10{sup {minus}10} cm{sup 3} molecule{sup {minus}1} s{supmore » {minus}1}.« less
COMPETITIVE PRICING AND EFFICIENCY IN SEARCH EQUILIBRIUM

We consolidate and generalize some results on price determination and efficiency in search equilibrium. Extending models by Rubinstein and Wolinsky and by Gale, heterogeneous buyers and sellers meet according to a general matching technology and prices are determined by a general bargaining condition. When the discount rate r and search costs converge to 0, we show that prices in all exchanges are the same and equal the competitive, market clearing, price. Given positive search costs, efficiency obtains iff bargaining satisfies Hosios' condition and r=0. When prices are set by third-party market makers, however, we show that search equilibrium is necessarily efficient.
A new technique for using thin magnetic films as a phase script memory element

The use of thin magnetic film memories for high speed computers has been well established. More recently, efforts have been made to adapt thin-film memory elements for operation in a phase script mode by using drive fields at two different frequencies to switch and read the state of the memory element. The resulting memory system is uniquely suited for operation in a parametron computer where information exists as a phase state rather than an amplitude state.
Female Labour Supply, Flexibility of Working Hours, and Job Mobility

Traditional labour supply models do not address to what extent working hours are constrained withinjobs, and to what extent working hours can be adjusted by means of changing employer. This paper measures the flexibility of working hours within and between jobs by relating subjective information on individual preferences to adjustments in working hours. Empirical analysis based on a sample of employed women in the Dutch Socio-Economic Panel (1987-9) shows that the flexibility of working hours withinjobs is low. The empirical literature on labour supply traditionally assumes that workers can choose their working hours freely and without costs, up to a maximum level equal to the time endowment. The potential invalidity of this assumption is acknowledged, but the assumption is still often made for the tractability of the empirical model. In response, several models incorporating restrictions on working hours have been developed. The first generation of these models extended the traditional censored regression model by allowing for censoring due to over- and under-employment and involuntary unemployment (Moffitt, 1982; Ham, 1982; Blundell et al., 1987). The second generation of models extended the structural labour supply model by introducing job offers concerning hours of work (Van Soest et al., 1990; Dickens and Lundberg, 1993). A conclusion stemming from all of these studies is that incorporating restrictions on working hours significantly improves the empirical fit of the model. A peculiar component of the models discussed above is that they are static. As a result they are not able to distinguish between the 'ingredients' required for the existence of hours restrictions within the labour market. First, there needs to be restrictions on the possibilities to adjust working hours with the same employer, for example, within a job. This alone does not necessarily imply that individuals are not on their labour supply curve, as they might switch to an employer that offers them their preferred working hours. A second necessary ingredient for the existence of hours restrictions within the labour market is therefore mobility costs. Although one cannot doubt the existence of hours restrictions in the labour market, an open question is how tight these restrictions actually are. Altonji and Paxson (1986, 1992) study adjustments of working hours over time, and distinguish between those individuals who stay in their job, and those who change job (change employer). Based on the US Panel Study of Income Dynamics, they conclude that working hours of married women are two to four
The Duty of Good Faith in American Corporate Law

An important development in American corporate law is the recent explicit recognition, in a series of Delaware cases, that corporate managers owe a fiduciary duty of good faith in addition to their traditional duties of care and loyality. The duty of good faith was not created by those cases. On the contrary, the duty has long been explicit under the statutes and has also long existed implicitly in the case law. Nevertheless, the explicit recognition of the duty of good faith in recent Delaware cases shines a spotlight on that duty, and therefore makes it especially important to develop the contours of the duty and to examine the duty from a normative perspective.
Linear interpolation models for rapidly-sampled data

A numerically stable linear interpolation model for time series obtained by rapidly sampling continuous-time processes is developed. This model is based on the use of a second-order incremental difference operator in place of the forward shift operator conventionally used to model discrete-time dynamics. Unlike conventional shift-based models, this model has a meaningful limit as the sampling period goes to zero. Moreover, this model is more parsimonious than a difference-based predictor-type model developed previously for such situations. An algorithm for estimating -order model parameters is derived by exploiting a Hankel property of the linear interpolation model formulated by the difference operator defined in this paper. Numerical results show that this algorithm produces significantly lower relative error with finite wordlength computations than the conventional shift-based algorithm does, especially at high sampling rates
X-Ray Absorption from the Milky Way Halo and the Local Group

Million degree gas is present at near-zero redshift and is due to either a gaseous Galactic halo or a more diffuse but very massive Local Group medium. We can discriminate between these models because the column densities should depend on location in the sky, either relative to the Galaxy bulge or to the M31-Milky Way axis. To search for these signatures, we measured the O VII Kα absorption-line strength toward 25 bright active galactic nuclei (AGNs), plus LMC X-3, using XMM-Newton RGS archival data. The data are in conflict with a purely Local Group model, but support the Galactic halo model. The strongest correlation is between the O VII equivalent widths and the ROSAT background emission measurement in the R45 band (0.4-1 keV), for which O VII emission makes the largest single contribution. This suggests that much of the O VII emission and absorption are cospatial, from which the radius of a uniform halo appears to lie the range 15-110 kpc. The present data do not constrain the type of halo gas model, and an equally good fit is obtained in a model where the gas density decreases as a power law, such as r-3/2. For a uniform halo with a radius of 20 kpc, the electron density would be 9 × 10-4 cm-3, and the gas mass is 4 × 108 M☉. The redshift of the four highest signal-to-noise ratio (S/N) O VII measurements is consistent with a Milky Way origin rather than a Local Group origin.
Superfield Formulation for Non-Relativistic Chern-Simons-Matter Theory

We construct a superfield formulation for non-relativistic Chern–Simons-matter theories with manifest dynamical supersymmetry. By eliminating all the auxiliary fields, we show that the simple action reduces to the one obtained by taking non-relativistic limit from the relativistic Chern–Simons-matter theory proposed in the literature. As a further application, we give a manifestly supersymmetric derivation of the non-relativistic ABJM theory.
The distance function to the boundary, Finsler geometry, and the singular set of viscosity solutions of some Hamilton-Jacobi equations†

We study the distance function to the boundary, Finsler geometry and the singular set of viscosity solutions of some Hamilton-Jacobi equations.
APERTURE SYNTHESIS IMAGING OF V892 Tau AND PV Cep: DISK EVOLUTION

I present a study of two Herbig Ae stars that are in completely different evolutionary stages: V892 Tau and PV Cep. Using sub-arcsecond interferometric observations obtained with the Combined Array for Research in Millimeter-wave Astronomy at λ = 1.3 and 2.7 mm, I have for the first time resolved their disks. I deduce that the 5 Myr old V892 Tau has a low dust opacity index β = 1.1 and a disk mass of ~0.03 M ☉. These values correspond to the growth of its dust into large, up to centimeters size, structures. In contrast, the very young (a few ×105 yr) PV Cep has a quite high opacity index β = 1.75 and a more massive disk 0.8 M ☉. PV Cep has the youngest resolved disk around any Herbig Ae star. Unlike the youngest T Tauri and Class 0 stars, which contain large and processed grains, the young Herbig Ae star, PV Cep, disk contains interstellar-medium-like unprocessed dust. This suggests that PV Cep's dust evolution is slower than T Tauri stars'. I also present high spatial resolution interferometric observations of the PV Cep outflow. The outflow inclination is consistent with the orientation of the known Herbig-Haro flow in that region, HH315.
Nalmefene for elective reversal of procedural sedation in children

Nalmefene is a newer, long-acting opioid antagonist. Its use in children for the elective reversal of emergency department procedures has not been investigated. The objective was to evaluate the safety of nalmefene in children. An open-label pediatric clinical trial was performed. The study was conducted at the emergency department of an urban, university-affiliated children's hospital and consisted of children aged 6 months to 12 years who required procedural sedation where an opioid agent was administered. Patients were excluded if there was altered mental status, history of head trauma, history of opioid allergy, or the anticipated need for opioid agents for pain relief after the procedure. At the completion of the procedure, nalmefene was administered in a dose of 0.25 microg/kg increments (max 10 microg) until sedation was resolved, or to a maximum of 1.0 microg/kg (max 40 microg). Serial ECGs, vital signs, and oxygen saturation were recorded. Sedation was assessed using the Clinical Global Impression Scale (CGIS) at baseline, 2, 4, 6, 8, and 10 minutes after the initial nalmefene dose. The observer's assessment of alertness and sedation (OAA/S) was measured at baseline, 10, 30, 60, 90, and 120 minutes after the first dose of nalmefene. Episodes of resedation were recorded. All patients received follow-up by telephone at 4 and 24 hours after the initial dose of nalmefene to identify any potential late adverse effects. Over the study interval 15 patients were enrolled. Mean age was 59.1 +/- 41.5 months. Procedures involved fracture reduction (n=8), laceration repair (n = 4), abscess drainage (n = 2), and arthrocentesis (n = 1). All patients received IV fentanyl and midazolam. The mean dosage of fentanyl and midazolam was 3.21 +/- 1.03 microg/kg and 0.07 +/- 0.03 mg/kg, respectively. The mean dose of nalmefene at the time of complete response (CGIS = 1 or 2) was 0.55 +/- 0.29 microg/kg. The median number of nalmefene doses was 2. All but one patient (93%) had a complete response based on CGIS at 10 minutes after the initial dose of nalmefene was given. Nalmefene resulted in a significant improvement in CGIS (1.60 +/- 0.82 v 3.26 +/- 0.88, P =.001) and OAA/S (median score 5 v 4) when compared at baseline with 10 minutes after the initial dose of nalmefene. Nalmefene also resulted in increased diastolic blood pressure (62.6 +/- 10.5 v 55.8 +/- 10.7, P =.04) as well as improved oxygen saturation when compared at 120 minutes to baseline (99.5 +/- 0.74% v 98.5 +/- 0.4%, P =.03). There were no significant changes in pulse, systolic blood pressure, respiratory rate, and ECG. None of the patients became resedated after nalmefene was given. One patient developed nausea and vomiting within the first 2 hours after nalmefene; this resolved without intervention before discharge. No adverse events occurred in any of the patients at 4 and 24 hours postadministration. The results of this study showed that nalmefene is effective and safe for reversal of procedural sedation by opioids in children.
The Renormalization of Meson Theories

A brief account is given of Dyson's proof of the finiteness after renormalization of the matrix elements for scattering processes ($S$-matrix elements) in electrodynamics (interaction of photons and electrons). It is shown to which meson interactions this proof can be extended and some of the difficulties which arose in this extension are discussed.
Reporting standards for angioplasty and stent-assisted angioplasty for intracranial atherosclerosis.

Background and Purpose Intracranial cerebral atherosclerosis causes ischemic stroke in a significant number of patients. Technological advances over the past 10 years have enabled endovascular treatment of intracranial atherosclerotic stenosis. The number of patients treated with angioplasty or stent-assisted angioplasty for this condition is increasing. Given the lack of universally accepted definitions, the goal of this document is to provide consensus recommendations for reporting standards, terminology, and written definitions when reporting clinical and radiological evaluation, technique, and outcome of endovascular treatment using angioplasty or stent-assisted angioplasty for stenotic and occlusive intracranial atherosclerosis. Summary of Report This article was written under the auspices of Joint Writing Group of the Technology Assessment Committee, Society of NeuroInterventional Surgery, Society of Interventional Radiology; Joint Section on Cerebrovascular Neurosurgery of the American Association of Neurological Surgeons and Congress of Neurological Surgeons; and the Section of Stroke and Interventional Neurology of the American Academy of Neurology. A computerized search of the National Library of Medicine database of literature (PubMed) from January 1997 to December 2007 was conducted with the goal to identify published endovascular cerebrovascular interventional data in stenotic intracranial atherosclerosis that could be used as benchmarks for quality assessment. We sought to identify those risk adjustment variables that affect the likelihood of success and complications. This document offers the rationale for different clinical and technical considerations that may be important during the design of clinical trials for endovascular treatment of intracranial stenotic and occlusive atherosclerosis. Included in this guidance document are suggestions for uniform reporting standards for such trials. These definitions and standards are primarily intended for research purposes; however, they should also be helpful in clinical practice and applicable to all publications. Conclusion In summary, the definitions proposed represent recommendations for constructing useful research data sets. The intent is to facilitate production of scientifically rigorous results capable of reliable comparisons between and among similar studies. In some cases, the definitions contained here are recommended by consensus of a panel of experts in this writing group for consistency in reporting and publication. These definitions should allow different groups to publish results that are directly comparable.
The one-dimensional Hubbard model: a reminiscence

Abstract In 1968 we published the solution of the ground state energy and wave function of the one-dimensional Hubbard model, and we also showed that there is no Mott transition in this model. Details of the analysis have never been published, however. As the Hubbard model has become increasingly important in condensed matter physics, relating to topics such as the theory of high-Tc superconductivity, it is appropriate to revisit the one-dimensional model and to recall here some details of the solution.
Synthesis of novel aryl-1,2-oxazoles from ortho-hydroxyaryloximes

The reaction of ortho-hydroxyaryloximes with p-toluenesulfonyl chloride in the presence of an amine base efficiently generates the corresponding aryl-1,2-oxazole. Investigations revealed that solvent polarity greatly affected the rate of the reaction with faster rates observed in more polar solvents. The reaction proceeds to completion in only a few minutes in acetonitrile at room temperature, and the synthesis of four novel aryl-1,2-oxazoles is presented.
THREE POSSIBLE ORIGINS FOR THE GAS LAYER ON GJ 1214b

We present an analysis of the bulk composition of the MEarth transiting super-Earth exoplanet GJ 1214b using planet interior structure models. We consider three possible origins for the gas layer on GJ 1214b: direct accretion of gas from the protoplanetary nebula, sublimation of ices, and outgassing from rocky material. Armed only with measurements of the planet mass (Mp = 6.55 ± 0.98 M ⊕), radius (Rp = 2.678 ± 0.13 R ⊕), and stellar irradiation level, our main conclusion is that we cannot infer a unique composition. A diverse range of planet interiors fits the measured planet properties. Nonetheless, GJ 1214b's relatively low average density (ρ p = 1870 ± 400 kg m–3) means that it almost certainly has a significant gas component. Our second major conclusion is that under most conditions we consider GJ 1214b would not have liquid water. Even if the outer envelope is predominantly sublimated water ice, the envelope will likely consist of a super-fluid layer sandwiched between vapor above and plasma (electrically conductive fluid) below at greater depths. In our models, a low intrinsic planet luminosity (2TW) is needed for a water envelope on GJ 1214b to pass through the liquid phase.
Teaching to the rating: School accountability and the distribution of student achievement

This paper examines whether minimum competency school accountability systems, such as those created under No Child Left Behind, influence the distribution of student achievement. Because school ratings in these systems only incorporate students' test scores via pass rates, this type of system increases incentives for schools to improve the performance of students who are on the margin of passing but does not increase short-run incentives for schools to improve other students' performance. Using student-level, panel data from Texas during the 1990's, I explicitly calculate schools' short-run incentives to improve various students' expected performance, and I find that schools do respond to these incentives. Students perform better than expected when their test score is particularly important for their schools' accountability rating. Also, low achieving students perform better than expected in math when many of their classmates' math scores are important for the schools' rating, while relatively high achieving students do not perform better. Distributional effects appear to be related to broad changes in resources or instruction, as well as narrowly tailored attempts to improve the performance of specific students.
A simple proof of the characterization of functions of low Aviles Giga energy on a ball via regularity

The Aviles Giga functional is a well known second order functional that forms a model for blistering and in a certain regime liquid crystals, a related functional models thin magnetized films. Given Lipschitz domain Ω ⊂ ℝ2 the functional is where u belongs to the subset of functions in whose gradient (in the sense of trace) satisfies Du (x )·η x = 1 where η x is the inward pointing unit normal to ∂Ω at x . In [Ann. Sc. Norm. Super. Pisa Cl. Sci. 1 (2002) 187–202] Jabin et al. characterized a class of functions which includes all limits of sequences with I ϵ n (u n ) → 0 as ϵ n → 0. A corollary to their work is that if there exists such a sequence (u n ) for a bounded domain Ω , then Ω must be a ball and (up to change of sign) u : = limn → ∞ u n = dist(·,∂Ω ). Recently [Lorent, Ann. Sc. Norm. Super. Pisa Cl. Sci. (submitted), http://arxiv.org/abs/0902.0154v1] we provided a quantitative generalization of this corollary over the space of convex domains using ‘compensated compactness’ inspired calculations of DeSimone et al. [Proc. Soc. Edinb. Sect. A 131 (2001) 833–844]. In this note we use methods of regularity theory and ODE to provide a sharper estimate and a much simpler proof for the case where Ω = B 1 (0) without the requiring the trace condition on Du .
Processing and Hard Magnetic Properties of Nanocrystalline Sm(Co,Zr)7 Magnet Powders

Isotropic nanocrystalline Sm(Co,Zr)7 permanent magnet powders of the TbCu7 type structure and with high coercivity and enhanced remanent magnetization has been synthesized by mechanically milling Sm12.5Co87.5-xZrx alloys (x = 0, 1, 2, 3) alloys and subsequently appropriate annealing. The mechanical-milling process of the alloys and the formation of nanostructured Sm(Co,Zr)7 magnet powders have been investigated with respect to hard magnetic properties. Hard magnetic properties are found to be strongly dependent upon the processing condition (like milling time, annealing temperature, etc.). Optimal coercivity Hci of value above 21 kOe has been obtained in Sm12.5Co85.5Zr2 magnet powders subjected to milling for 5 hr and annealing at 600°C for 20min. Optimal remanent magnetization Mr of 73.4 emu/g, remanence ratio Mr/Ms of 0.71, and maximum energy products (BH)max of over 13 MGOe have been realized in Sm12.5Co87.5-xZrx (x = 1, 2) magnet powders with grain size of 15-20 nm. The hard magnetic properties are ascribed to the nanosized Sm(Co,Zr)7 phase of the TbCu7 type structure with grain size of 10-20 nm. The enhancement of remanent magnetization may be contributed from the enhanced exchange-coupling interaction between nanosized grains.
Common characteristics of epilepsy and schizophrenia: clinical observation and depth electrode studies☆☆☆☆☆☆

Data presented, gathered by special techniques, add some clarification to the nature of the seemingly similar and related disease processes of schizophrenia and epilepsy. These data indicate that schizophrenia and epilepsy probably are different entities.
Photocyclization of α,β-unsaturated amide aldehydes synthesis of jatropham

Abstract α,β-unsaturated amide aldehydes undergo photoisomerization and intramolecular cyclization to provide hydroxy substituted pyrrolidinone systems. A synthesis of the natural product jatropham was accomplished by application of this procedure.
Caring for Parents of Sick Newborns

This paper is concerned with the care needed by parents who give birth to a "high risk" infant. Interviews with eight families demonstrate the diversity of responses to this anxiety-producing situation.
Giant intrinsic magnetic hardness

Crystallographically partly randomized materials with high magnetic anisotropy exhibit anisotropy and exchange fluctuations. Possibly the most dramatic consequence of these interaction fluctuations is the presence of giant intrinsic magnetic hardness observed, especially at cryogenic temperatures. This magnetic hardness (resistance to demagnetization) is anintrinsic solid state property, quite in contrast with hardness in technologically important materials based on the presence of fine particles or precipitate phases. It introduces rather a further variety in the phenomenology of interaction fluctuation materials such as spin glasses, representing the extreme case of high anisotropy and high moment concentrations. In this paper the phenomenon of strong intrinsic magnetic hardness is reviewed, and some new experimental data are presented for homogeneous pseudobinary regions of composition on the basis of such compounds as SmNi5, SmCu5, SmCo5, TbFe2 and others. Magnetic hardness in some of these cases reaches the highest values found so far for any class of materials. For instance, maximum values of coercive force of aboutH c=230 kOe are observed for SmCo5−xNix. Even higher values are extrapolated in other cases. Maximum values ofH c are observed in materials with ordering temperatures of order 60–200 K. A strong temperature and a weaker time dependence ofH c is observed and discussed on the basis of theories involving thermal activation of domain propagation. Comparisons are drawn with effects generally observed in magnetically hard materials, and the relationship of intrinsic magnetic hardness to technologically interesting materials is discussed. Tentative conclusions as to the details of the origins of giant intrinsic magnetic hardness are drawn and areas of future interest are indicated.
Synthesis, modification, and characterization of a family of homologues of exo-calix

A general strategy for the preparation of the family of exo-[n.m.n.m]metacyclophanes (n,m ≥ 3) in 6-steps (starting from 2-bromoanisole) that utilizes a [2 + 2] approach to furnish the exo-metacyclophane ring in good to moderate yield is described. The soluble copper catalyst [CuBr−LiSPh−LiBr−THF] is used to efficiently couple Grignard and alkyl or ether tosylate reagents in several of the synthetic steps, including the ring construction in the final step. The exo-[n.m.n.m]metacyclophane ring is conformationally mobile on the NMR time scale, and X-ray crystallography reveals that exo-[3.3.3.3]metacyclophane 2a assumes a cone conformation, and that exo-[6.6.6.6]metacyclophane 6a assumes a chair conformation. Molecular mechanics calculations show that both conformations for each exo-metacyclophane are very similar in energy. Regiocontrol over the alkylation and acylation of the phenolic oxygens of 2b is problematic, although the preparation of the tetraacetylated 18 and alkylation of 2b with CH2BrCl to furn...
Homogeneous and inhomogeneous sources of optical transition broadening in room temperature CdSe/ZnS nanocrystal quantum dots

We perform photoluminescence excitation measurements on individual CdSe/ZnS nanocrystal quantum dots (NCQDs) at room temperature to study optical transition energies and broadening. The observed features in the spectra are identified and compared to calculated transition energies using an effective mass model. The observed broadening is attributed to phonon broadening, spectral diffusion, and size and shape inhomogeneity. The former two contribute to the broadening transitions in individual QDs, while the latter contributes to the QD-to-QD variation. We find that phonon broadening is often not the dominant contribution to transition line widths, even at room temperature, and that broadening does not necessarily increase with transition energy. This may be explained by differing magnitude of spectral diffusion for different quantum-confined states.
Numerical smoothness and error analysis for RKDG on the scalar nonlinear conservation laws

The new concept of numerical smoothness is applied to the RKDG (Runge-Kutta/Discontinuous Galerkin) methods for scalar nonlinear conservations laws. The main result is an a posteriori error estimate for the RKDG methods of arbitrary order in space and time, with optimal convergence rate. In this paper, the case of smooth solutions is the focus point. However, the error propagation analysis framework is prepared to deal with discontinuous solutions in the future.
Recent developments in pressure altimetry

Some of the more significant accomplishments of recent years relating to the improvement of instruments, the measurement and compensation of the errors of static-pressure systems, and the collection of information on the flight technical error are reviewed. Previous studies of the relation between altimetry errors and vertical separation standards are discussed, and the problem of assessing vertical separation standards is examined from an approach different from that used in those studies. On the basis of the present review, the need for further work is indicated for standardizing the calibrations of static-pressure systems, for collecting additional information on the flight technical error, for developing an altitude-deviation monitoring and warning device, and for improving the maintenance practices relating to the testing and installation of the instruments.
Knuth relations for the hyperoctahedral groups

C. Bonnafe, M. Geck, L. Iancu, and T. Lam have conjectured a description of Kazhdan-Lusztig cells in unequal parameter Hecke algebras of type B which is based on domino tableaux of arbitrary rank. In the integer case, this generalizes the work of D. Garfinkle. We adapt her methods and construct a family of operators which generate the equivalence classes on pairs of arbitrary rank domino tableaux described in the above conjecture.
Toward a complexity science of entrepreneurship

Abstract Darwinian selectionist theory is characterized as equilibrium bound. Complexity science focuses on order creation, hence is a better platform for a science of entrepreneurship. “Self-organization biologists” study order creation in the context of all four Aristotelian causes: material , formal , final , and efficient , whereas normal science rests only on efficient cause. Mohr's process theory and Siggelkow's narrative about entrepreneurship rest on all four, standing as good representations of postmodernist ontology. Since modern epistemology still calls for model-centered science, agent models are proposed as an alternative to mathematics as a means of applying modern normal science standards to research on entrepreneurship—all without downgrading thick, postmodernist descriptions of complex causality.
Learning by Exporting: New Insights from Examining Firm Innovation

Empirical findings across many nations show that exporters have superior productivity compared to nonexporters and that this relationship is driven by productive firms becoming exporters. The conclusion drawn from these studies is that there is little learning from exporting. We, however, assess if there are ex post benefits that accrue to exporting firms by examining innovation outcomes. We argue that exporters can often access diverse knowledge inputs not available in the domestic market, that this knowledge can spill back to the focal firm, and that such learning can foster increased innovation. We examine product innovation and patent application counts of a representative sample of Spanish manufacturing firms from 1990 to 1997. To conduct the analysis, we use a nonlinear GMM estimator for exponential models with panel data that allows for predetermined regressors and linear feedback. We find that exporting is associated with innovation. Moreover, the panel data allow us to explore the temporal relationship between exporting and innovation. In contrast to existing findings, we find evidence of learning by exporting—albeit in dimensions not previously examined in the literature.
Lattice gases and cellular automata

Abstract We review the class of cellular automata known as lattice gases, and their applications to problems in physics and materials science. The presentation is self-contained, and assumes very little prior knowledge of the subject. Hydrodynamic lattice gases are emphasized, and non-lattice-gas cellular automata – even those with physical applications – are not treated at all. We begin with a review of lattice gases as the term is understood in equilibrium statistical physics. We then discuss the various methods that have been proposed to simulate hydrodynamics with a lattice gas, leading up to the 1986 discovery of a lattice gas for the isotropic Navier–Stokes equations. Finally, we discuss variants of lattice-gas models that have been used for the simulation of complex fluids.
Mechanically-Tunable Composite Filter at Low Frequencies

Previous studies into the possibility of a plasmonic medium of a coiled conductor array in air have shown promise. This work serves to evaluate the possibility of creating a mechanically-tunable composite filter at low frequencies. Copper springs were created with varying starting pitches using a coil winder. These springs were then embedded into a flexible host polymer. The mechanical and electromagnetic properties of each spring design were predicted and tested. Two horn antennas were used to characterize the overall electromagnetic (EM) properties of the composite. The pitch of each spring was increased mechanically through application of force to the entire polymermetal composite at equal intervals, with an EM test completed at each step. Using an Agilent 8510C Vector Network Analyzer (VNA), the frequency spectrum within the microwave range was scanned. Relative amplitude and phase measurements were taken at equal frequency and pitch steps. With no polymer surrounding the springs, plasmon turn-on frequencies were observed to span the microwave bands as the pitch of the springs were increased. Similar results are expected with the springs embedded in a polymeric matrix. These results suggest a method of creating a mechanically-tunable composite filter for use at low frequencies.
Detection of Gearbox Bearing Defects Using Electrical Signature Analysis for Doubly Fed Wind Generators

Drivetrain failures may cause severe damage to wind turbines. In the previous work, detection of failures in generator bearing and gearbox gears using electrical signature analysis (ESA) has been investigated. However, the detection of defects of bearings in the gearboxes has been a major gap. Bearing defects in gearboxes are believed to be one of the root causes of wind drivetrain failures. In this paper, a novel ESA-based monitoring technique is proposed for monitoring gearbox bearing defects in wind turbines, which is the first ESA technique reported that is capable of detecting bearing defects in gearboxes. A novel electrical signature tool, i.e., electrical multiphase imbalance separation technique, has been used to improve the signal-to-noise ratio in ESA. The principle of gearbox bearing defect detection is presented in detail. The proposed approach is validated by experimental results obtained from a 25-hp wind drivetrain simulator, which is designed to simulate 1.5-MW wind turbines as well as in the field on 1.5-MW wind turbines. The experimental results show that the proposed approach is capable of providing accurate detection of gearbox bearing failures at an early stage. The proposed approach is cost-effective, with reliable detection of defects compared to existing techniques.
Genome-wide probing of RNA structure reveals active unfolding of mRNA structures in vivo

RNA has a dual role as an informational molecule and a direct effector of biological tasks. The latter function is enabled by RNA's ability to adopt complex secondary and tertiary folds and thus has motivated extensive computational and experimental efforts for determining RNA structures. Existing approaches for evaluating RNA structure have been largely limited to in vitro systems, yet the thermodynamic forces which drive RNA folding in vitro may not be sufficient to predict stable RNA structures in vivo. Indeed, the presence of RNA-binding proteins and ATP-dependent helicases can influence which structures are present inside cells. Here we present an approach for globally monitoring RNA structure in native conditions in vivo with single-nucleotide precision. This method is based on in vivo modification with dimethyl sulphate (DMS), which reacts with unpaired adenine and cytosine residues, followed by deep sequencing to monitor modifications. Our data from yeast and mammalian cells are in excellent agreement with known messenger RNA structures and with the high-resolution crystal structure of the Saccharomyces cerevisiae ribosome. Comparison between in vivo and in vitro data reveals that in rapidly dividing cells there are vastly fewer structured mRNA regions in vivo than in vitro. Even thermostable RNA structures are often denatured in cells, highlighting the importance of cellular processes in regulating RNA structure. Indeed, analysis of mRNA structure under ATP-depleted conditions in yeast shows that energy-dependent processes strongly contribute to the predominantly unfolded state of mRNAs inside cells. Our studies broadly enable the functional analysis of physiological RNA structures and reveal that, in contrast to the Anfinsen view of protein folding whereby the structure formed is the most thermodynamically favourable, thermodynamics have an incomplete role in determining mRNA structure in vivo.
A HYBRID FINITE ELEMENT FORMULATION FOR MID-FREQUENCY ANALYSIS OF SYSTEMS WITH EXCITATION APPLIED ON SHORT MEMBERS

A hybrid finite element method for computing mid-frequency vibrations is presented. In the mid-frequency region a system is comprised by some members that contain several wavelengths and some members that contain a small number of wavelengths within their dimensions. The former are considered long members and they are modelled by the energy finite element analysis (EFEA). The latter are considered short and they are modelled by the finite element analysis (FEA). In this paper the excitation is considered to be applied on the short members. The hybrid formulation computes the response of the entire system. The characteristics of the long members affect the behavior of the short members and the amount of power flow between the members of the system. The resonant characteristics of the short members and the boundary conditions imposed by the long members determine the amount of input power into the system. The interaction between members is described by a set of equations between the FEA and the EFEA primary variables at the interfaces between long and short members. The equations for the short and the long members and the interface equations are solved simultaneously. A theoretical formulation and a numerical implementation for systems that contain one wave type is presented. Analytical solutions for several co-linear beam configurations are compared to numerical results produced by the hybrid finite element method. Good correlation is observed for all analyses.
Friction and wear of ceramics

The adhesion, friction, wear and lubricated behaviors of both oxide and non-oxide ceramics are reviewed. Ceramics are examined in contact with themselves, other harder materials and metals. Elastic, plastic and fracture behavior of ceramics in solid state contact is discussed. The contact load necessary to initiate fracture in ceramics is shown to be appreciably reduced with tangential motion. Both friction and wear of ceramics are anisotropic and relate to crystal structure as with metals. Grit size effects in two- and three-body abrasive wear are observed for ceramics. Both free energy of oxide formation and the d valence bond character of metals are related to the friction and wear characteristics for metals in contact with ceramics. Surface contaminants affect friction and adhesive wear. For example, carbon on silicon carbide and chlorine on aluminum oxide reduce friction while oxygen on metal surfaces in contact with ceramics increases friction. Lubrication increases the critical load necessary to initiate fracture of ceramics both in indentation and with sliding or rubbing.
Calculated properties of C60 isomers and fragments

Abstract MNDO calculations have been carried out for three C 60 isomers, buckminsterfullerene ( I h ), graphitene ( D 6h ), and a planar ring ( D 60h ). Buckminsterfullerene is 880.2 kcal mol −1 more stable than the ring structure while graphitene is 648.7 kcal mol −1 more stable (1 kcal mol −1 = 4.184 kJ mol −1 ). Optimized geometric parameters and orbital energies are also reported. A novel mechanism for formation of the I h structure is presented which involves a minimum of rearrangement.
The impact of industry environment on early market entry decisions by B2B managers in the U.S. and Japan

Managers form simplified mental models to cope with market environment uncertainties and to process information. A critical decision is whether to enter a high-potential market early. Large innovation and development investments involved in this decision increase uncertainty. We examine the importance ascribed by U.S. and Japanese managers to competitive forces when making early market entry decisions. We expect that the competitive forces will have different effects on the likelihood of early market entry in the U.S. versus Japan due to cultural and business environment differences, and we thereby develop several propositions. We develop a decision-making exercise simulating early market entry decisions, and tested our propositions with managers in medium to large business-to-business (B2B) firms from both countries. We assessed impacts of the competitive market forces on entry strategy selection via relative weights, repeated-measures analysis of variance, and frequency analysis. Our findings revealed differences in the mental models of Japanese and U.S. managers. Buyer power had a larger effect on the decision to make an early market entry for Japanese managers, while threat of new firm entry had a larger effect for U.S. managers; these findings were consistent with our propositions. We also found several areas of agreement between U.S. and Japanese managers. We conclude with theoretical implications and recommendations to B2B management.
Tropical Mixtures of Star Tree Metrics

We study tree metrics that can be realized as a mixture of two star tree metrics. We prove that the only trees admitting such a decomposition are the ones coming from a tree with at most one internal edge, and whose weights satisfy certain linear inequalities. We also characterize the fibers of the corresponding mixture map. In addition, we discuss the general framework of tropical secant varieties and we interpret our results within this setting. Finally, we show that the set of tree metric ranks of metrics on fixed taxa is unbounded.
Rhodium-catalyzed direct synthesis of unprotected NH-sulfoximines from sulfoxides

A novel rhodium-catalyzed imination of sulfoxides using O-(2,4-dinitrophenyl)hydroxylamine is developed under mild conditions with good functional group tolerance. This method provides an efficient access to free NH-sulfoximines, an important structural unit in a variety of biologically active compounds.
Evolution of the Loop-Top Source of Solar Flares: Heating and Cooling Processes

We present a study of the spatial and spectral evolution of the loop-top (LT) sources in a sample of six flares near the solar limb observed by RHESSI. A distinct coronal source, which we identify as the LT source, was seen in each of these flares from the early "preheating" phase through the late decay phase. Spectral analyses reveal an evident steep power-law component in the preheating and impulsive phases, suggesting that the particle acceleration starts upon the onset of the flares. In the late decay phase the LT source has a thermal spectrum and appears to be confined within a small region near the top of the flare loop and does not spread throughout the loop, as is observed at lower energies. The total energy of this source decreases usually faster than expected from the radiative cooling but much slower than that due to the classical Spitzer conductive cooling along the flare loop. These results indicate the presence of a distinct LT region, where the thermal conductivity is suppressed significantly and/or there is a continuous energy input. We suggest that plasma wave turbulence could play important roles in both heating the plasma and suppressing the conduction during the decay phase of solar flares. With a simple quasi-steady loop model we show that the energy input in the gradual phase can be comparable to that in the impulsive phase and demonstrate how the observed cooling and confinement of the LT source can be used to constrain the wave-particle interaction.
THE METAL–INSULATOR TRANSITION IN THE HUBBARD MODEL AT ZERO TEMPERATURE II

We study the metal-to-insulator transition of the Hubbard model at zero temperatures in infinite dimensions. The coexistence of metallic and insulating solutions for a finite range of the interaction is established. It is shown that the metallic solution is lower in energy for any interaction in the coexistence region and that the transition is of second order.
On Universal Cycles for new Classes of Combinatorial Structures

A universal cycle (u-cycle) is a compact listing of a collection of combinatorial objects. In this paper, we use natural encodings of these objects to show the existence of u-cycles for collections of subsets, restricted multisets, and lattice paths. For subsets, we show that a u-cycle exists for the $k$-subsets of an $n$-set if we let $k$ vary in a non zero length interval. We use this result to construct a “covering” of length $(1+o(1))$$n \choose k$ for all subsets of $[n]$ of size exactly $k$ with a specific formula for the $o(1)$ term. We also show that u-cycles exist for all $n$-length words over some alphabet $\Sigma,$ which contain all characters from $R \subset \Sigma.$ Using this result we provide u-cycles for encodings of Sperner families of size 2 and proper chains of subsets.