cssi/SciSciGPT-SciSciNet huggingface dataset:
Linear theory of uncompensated thermal blooming in turbulence

A linearized theory of small perturbations in thermal blooming gives a surprisingly accurate description of the initial evolution of a plane wave propagating through an absorbing fluid medium. In the case of constant absorption and fluid velocity, a sinusoidal perturbation of the optical field grows quasiexponentially at a rate determined by its Fresnel number and the accumulated optical-path difference due to blooming. Perturbations with small transverse length scales grow more rapidly than those with large length scales. The evolution of the optical field and spectrum in the presence of optical turbulence is accurately described. The growth of the small-scale fluctuations eventually leads to a decrease in plane-wave amplitude. This growth puts an ultimate limit on the amount of power that can be propagated through a turbulent medium such as the atmosphere. More complicated cases with varying absorption and velocity profiles can be analyzed using a WKB approximation. Numerical simulations show growth suppression when the velocity varies along the optical path. These predictions from the linearized theory agree well with results from numerical simulations of the full nonlinear system and thus provides a standard for comparing different numerical codes.
Absolute Properties of the Eclipsing Binary Star AP Andromedae

AP And is a well-detached F5 eclipsing binary star for which only a very limited amount of information was available before this publication. We have obtained very extensive measurements of the light curve (19,097 differential V magnitude observations) and a radial velocity curve (83 spectroscopic observations) which allow us to fit orbits and determine the absolute properties of the components very accurately: masses of 1.277 ± 0.004 and 1.251 ± 0.004 M {sub ☉}, radii of 1.233 ± 0.006 and 1.1953 ± 0.005 R {sub ☉}, and temperatures of 6565 ± 150 K and 6495 ± 150 K. The distance to the system is about 400 ± 30 pc. Comparison with the theoretical properties of the stellar evolutionary models of the Yonsei-Yale series of Yi et al. shows good agreement between the observations and the theory at an age of about 500 Myr and a slightly sub-solar metallicity.
Uniform Zariski’s theorem on fundamental groups

The Zariski theorem says that for every hypersurface in a complex projective (resp. affine) space and for every generic plane in the projective (resp. affine) space the natural embedding generates an isomorphism of the fundamental groups of the complements to the hypersurface in the plane and in the space. If a family of hypersurfaces depends algebraically on parameters then it is not true in general that there exists a plane such that the natural embedding generates an isomorphism of the fundamental groups of the complements to each hypersurface from this family in the plane and in the space. But we show that in the affine case such a plane exists after a polynomial coordinate substitution.
OVERLAPPING WINDOW ALGORITHM FOR COMPUTING GVT IN TIME WARP

This paper proposes techniques for computing a global virtual time (GVT), which is the minimum local virtual time of processes in Time Warp. The algorithm computes a conservative estimate of GVT us...
Geographic control of Titan's mid-latitude clouds.

Observations of Titan's mid-latitude clouds from the W. M. Keck and Gemini Observatories show that they cluster near 350°W longitude, 40°S latitude. These clouds cannot be explained by a seasonal shift in global circulation and thus presumably reflect a mechanism on Titan such as geysering or cryovolcanism in this region. The rate of volatile release necessary to trigger cloud formation could easily supply enough methane to balance the loss to photolysis in the upper atmosphere.
The effect of bed roughness on scalar fluctuations in turbulent boundary layers

The effect of bed roughness on an iso-kinetic chemical plume released into the logarithmic region of the bed boundary layer of an open channel flow is examined. The bed roughness is varied systematically to generate flows in the smooth (painted polyethylene sheets), transitional rough (2.5-mm and 11.5-mm gravel beds), and fully rough (21.0-mm gravel bed) regimes. Concentration fields are measured in horizontal planes using the planar laser-induced fluorescence (PLIF) technique. The time-averaged concentration follows a self-similar Gaussian transverse profile for each bed roughness. The plume width grows as a power law function of the streamwise distance (i.e., % MathType!Translator!2!1!AMS LaTeX.tdl!TeX -- AMS-LaTeX! % MathType!MTEF!2!1!+- % feaafiart1ev1aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiFu0Je9IqLqpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaeq4WdmNaey % yhIuRaamiEamaaCaaaleqabaGaamOBaaaakiaacYcaaaa!3BCE! $$\sigma \propto x^n ,$$ with n≈0.75 near the source and n≈0.5 farther downstream). As the bed roughness increases, the variance of the fluctuations is smaller and decreases faster. Near the plume source, the transverse profiles of the standard deviation of the scalar fluctuations are self-similar and Gaussian. For the two rougher beds, the transverse distribution of the standard deviation transitions downstream to a bi-modal profile. The probability density functions (PDFs) of the concentration fluctuations near the plume source are highly skewed distributions. Increased bed roughness accelerates the approach of the PDF towards a Gaussian distribution.
Chemical reactivity and functionalization of C60 and C70 fullerenes

Abstract This account discusses the chemical reactivity and various functionalizations of C 60 and C 70 fullerenes with emphasis on results derived from the authors' laboratory.
Restricted Mean Life with Adjustment for Covariates

Abstract Although the mean is the most widely used measure of location in comparing two distributions, its use is essentially precluded in the presence of substantial censoring, typical in survival analysis of medical therapies. To accommodate censoring, Irwin (1949) proposed estimation of the expectation of life restricted to a time T, using the actuarial estimator of the survival function. In this article we examine the restricted mean as an index for comparing survival in two groups and then extend the method to incorporate covariates into the analysis. For this purpose it is convenient to depart slightly from the actuarial approach and to consider piecewise exponential models. Asymptotic properties are explored, and the assumption of piecewise exponentiality is shown to be rather mild, as departures from the model have a relatively small effect on estimation of the restricted mean. The methodology is illustrated using published data from a study conducted by the Radiation Therapy Oncology Group (RTOG)...
Minimum distances in non-trivial string target spaces

Abstract The idea of minimum distance, familiar from R ↔ 1 R duality when the string target space is a circle, is analyzed for less trivial geometries. The particular geometry studied is that of a blown-up quotient singularity within a Calabi-Yau space and mirror symmetry is used to perform the analysis. It is found that zero distances can appear but that in many cases this requires other distances within the same target space to be infinite. In other cases zero distances can occur without compensating infinite distances.
The Orbifold-String Theories of Permutation-Type Iii:. Lorentzian and Euclidean SPACE—TIMES in a Large Example

To illustrate the general results of the previous paper, we discuss here a large concrete example of the orbifold-string theories of permutation-type. For each of the many subexamples, we focus on evaluation of the target space–time dimension, the target space–time signature and the target space–time symmetry of each cycle j in each twisted sector σ. We find in particular a gratifying space–time symmetry enhancement which naturally matches the space–time symmetry of each cycle to its space–time dimension. Although the orbifolds of ℤ2-permutation-type are naturally Lorentzian, we find that the target space–times associated with larger permutation groups can be Lorentzian, Euclidean and even null , with varying space–time dimensions, signature and symmetry in a single orbifold.
Boron Triiodide-N-N-diethylaniline Complex: A New Reagent for Cleaving Esters

Abstract Boron triiodide N,N-diethylaniline complex was used for the hydrolysis, transesterification, and aminolysis of esters.
Higher-dimensional linking integrals

We derive an integral formula for the linking number of two sub-manifolds of the n-sphere S n , of the product S n x ℝ m , and of other manifolds which appear as "nice" hypersurfaces in Euclidean space. The formulas are geometrically meaningful in that they are invariant under the action of the special orthogonal group on the ambient space.
Development of benzothiazole ‘click-on’ fluorogenic dyes

'Click-on' fluorogenic reaction: a non-fluorescent benzothiazole with an electron-deficient alkyne group at 2-position reacts with azide containing molecules could form fluorescent adducts.
A DATA-ANALYTIC METHOD FOR FORECASTING NEXT RECORD CATASTROPHE LOSS

We develop in this article a data-analytic method to forecast the severity of next record insured loss to property caused by natural catastrophic events. The method requires and employs the knowledge of an expert and accounts for uncertainty in parameter estimation. Both considerations are essential for the task at hand because the available data are typically scarce in extreme value analysis. In addition, we consider three-parameter Gamma priors for the parameter in the model and thus provide simple analytical solutions to several key elements of interest, such as the predictive moments of record value. As a result, the model enables practitioners to gain insights into the behavior of such predictive moments without concerning themselves with the computational issues that are often associated with a complex Bayesian analysis. A data set consisting of catastrophe losses occurring in the United States between 1990 and 1999 is analyzed, and the forecasts of next record loss are made under various prior assumptions. We demonstrate that the proposed method provides more reliable and theoretically sound forecasts, whereas the conditional mean approach, which does not account for either prior information or uncertainty in parameter estimation, may provide inadmissible forecasts.
Distributed Linear Convolutive Space-Time Codes for Asynchronous Cooperative Communication Networks

In user cooperative communications, time offsets among the relay nodes may distort the structure of a distributed space-time code, and therefore impair the diversity gain. In this paper, a distributed linear convolutive space-time coding scheme is proposed for asynchronous scenario. We present a systematic construction method of distributed linear convolutive space-time codes that can achieve the full diversity under any delay profile. Furthermore, we show that with the MMSE decision feedback equalizer (MMSE-DFE) receiver, our proposed codes also achieve the full diversity, even when time offsets occur.
Targeting drugs to the brain by redox chemical delivery systems

Chemical delivery systems (CDSs) based on the redox conversion of a lipophilic dihydropyridine to an ionic, lipid-insoluble pyridinium salt have been developed to improve the access of therapeutic agents to the central nervous system. A dihydropyridinium-type CDS or a redox analog of the drug is sufficiently lipophilic to enter the brain by passive transport, then undergoes an enzymatic oxidation to an ionic pyridinium compound, which promotes retention in the CNS. At the same time, peripheral elimination of the entity is accelerated due to facile conversion of the CDS in the body. This review discusses chemical, physicochemical, biochemical, and biological aspects in relation to the principles and practical implementation of the redox brain-targeting approach to various classes of drugs. Representative examples to the brain-enhanced delivery of neurotransmitters, steroids, anticonvulsants, antibiotics, antiviral, anticancer and antidementia agents, and neuropeptides and their analogs are presented in detail. In vivo and in vitro studies and preliminary clinical data of several novel derivatives have been promising, which could lead to a practical use of the redox CDSs after proper pharmaceutical development. The investigations accentuate the need for considering physicochemical, metabolic, and pharmacokinetic properties in designing of carrier systems that are able to target drugs into the central nervous system.
First Results from a Photometric Survey of Strong Gravitational Lens Environments

Many strong gravitational lenses lie in complex environments, such as poor groups of galaxies, that significantly bias conclusions from lens analyses. We are undertaking a photometric survey of all known galaxy-mass strong lenses to characterize their environments and include them in careful lens modeling, as well as to build a large, uniform sample of galaxy groups at intermediate redshifts for evolutionary studies. In this paper we present wide-field photometry of the environments of 12 lens systems with 0.24 ≤ zlens ≤ 0.5. Using a red sequence identifying technique, we find that 8 of the 12 lenses lie in groups and that 10 group-like structures are projected along the line of sight toward 7 of these lenses. Follow-up spectroscopy of a subset of these fields confirms these results. For lenses in groups, the group centroid position is consistent with the direction of the external tidal shear required by lens models. Lens galaxies are not all super-L* elliptical galaxies; the median lens luminosity is L*, and the distribution of lens luminosities extends 3 mag below L* (in agreement with theoretical models). Only two of the lenses in groups are the brightest group galaxy, in qualitative agreement with theoretical predictions. As in the local universe, the highest velocity dispersion (σ) groups contain a brightest member spatially coincident with the group centroid, whereas lower σ groups tend to have an offset brightest group galaxy. This suggests that higher σ groups are more dynamically relaxed than lower σ groups and that at least some evolved groups exist by z ~ 0.5.
The optimum one-dimensional magnetohydrodynamic slider bearing

Calculus of variations used for determining optimum one dimensional MHD slider bearing with bounded control variables
Dynamics of Accretion Flows Irradiated by a Quasar

We present results from axisymmetric time-dependent hydrodynamical calculations of gas flows under the influence of the gravity of black holes in quasars. We assume that the flows are nonrotating and exposed to quasar radiation. We take into account X-ray heating and the radiation force due to electron scattering and spectral lines. To compute the radiation field, we consider an optically thick, geometrically thin, standard accretion disk as a source of UV photons and a spherical central object as a source of X-rays. The gas temperature and ionization state in the flow are calculated self-consistently from the photoionization and heating rate of the central object. We find that for a 108 M☉ black hole with an accretion luminosity of 0.6 of the Eddington luminosity, the flow settles into a steady state and has two components: (1) an equatorial inflow and (2) a bipolar inflow/outflow with the outflow leaving the system along the disk rotational axis. The inflow is a realization of a Bondi-like accretion flow. The second component is an example of a nonradial accretion flow becoming an outflow once it is pushed close to the rotational axis where thermal expansion and radiation pressure accelerate it outward. Our main result is that the existence of the above two flow components is robust to the outer boundary conditions and the geometry and spectral energy distribution of the radiation field. However, the flow properties are not robust. In particular, the outflow power and collimation is higher for the radiation dominated by the UV/disk emission than for the radiation dominated by the X-ray/central engine emission. Our most intriguing result is that a very narrow outflow driven by radiation pressure on lines can carry more energy and mass than a broad outflow driven by thermal expansion.
Robust microvalves for hydraulic actuators

Robust compact hydraulic actuators are extremely needed in space industry where payload is critical. Microvalves are key component for compact hydraulic actuators. Robust microvalves with large load bearing ability, large flow rate, and high operational frequency are objectives of this research. A FEM analytical approach was used to optimize the valve design. The microvalves were fabricated by novel microfabrication process and scaling laws. Electroformed nickel on silicon substrate was used to make the valve flap and deep RIE etching was adopted to make the valve channels while the metallic valve flap as the etching stop. Test results shown that the flow rate is proportional to the pressure applied. The flow rate is larger than 10 cc/sec at pressure or 40 psi. These microvalves can be used to solve engineering problems where both load bearing and flow rate are major concerns.
Émergences anxieuses à l’adolescence

Resume La clinique de l’adolescence nous apprend que toutes les formes d’angoisse peuvent se rencontrer. La clinique nosographique nous permet d’observer tous les types d’etats anxieux, la clinique psychanalytique de ces etats nous amene tout autant a pouvoir differencier, comme Freud nous l’a propose, ceux dans lesquels domine l’effroi, ceux dans lesquels domine la peur et ceux dans lesquels domine l’angoisse. Les conditions de survenue de ces etats constituent une autre question. L’abreaction (le trop de…), l’impreparation (la surprise face a…), le jeu entre deux « scenes » (l’apres coup de…) seront souvent evoques. Si specificite a l’adolescence il y a, elle reside pour nous dans l’attente d’objet, ce qui pourrait expliquer que l’emergence anxieuse caracteristique pour tous de cette periode du developpement est ce que nous avons appele la « menace depressive », transformation a l’adolescence des angoisses de l’enfant plus jeune.
Synthesis of a novel boronated 1-aminocyclobutanecarboxylic acid as a potential boron neutron capture therapy agent

A boronated aminocyclobutanecarboxylic acid was synthesized for potential use in neutron capture therapy. The synthesis involves the preparation of hydroxymethylcyclobutanone ketal, which is then converted to an amino acid using Bucherer–Strecker methodology. The molecule is modeled after the unnatural amino acid, 1-aminocyclobutanecarboxylic acid, which has demonstrated high uptake in brain tumors. Copyright © 2003 John Wiley & Sons, Ltd.
Aerogel: Space exploration applications

The unique physical properties of aerogel have proven to be enabling to a variety of both flight and proposed space exploration missions. The extremely low density and highly porous nature of aerogel makes it suitable for stopping high velocity particles, as a highly efficient thermal barrier, and as a porous medium for the containment of cryogenic fluids. The use of silica aerogel as a hypervelocity particle capture and return media for the Stardust Mission has drawn the attention of many in the space exploration community. Aerogel is currently being used as the thermal insulation material in the 2003 Mars Exploration Rovers. The SCIM (Sample Collection for the Investigation of Mars) and the STEP (Satellite Test of the Equivalence Principle) Missions are both proposed space exploration missions, in which, the use of aerogel is critical to their overall design and success. Composite materials comprised of silica aerogel and oxide powders are under development for use in a new generation of thermoelectric devices that are planned for use in many future space exploration mission designs. Work is currently ongoing in the development and production of non-silicate and composite aerogels to extend the range of useful applications envisioned for aerogel in future space exploration projects.
Collective intentional behavior from the standpoint of semantics

sense, it requires the members of the group to intend that they perform the joint action by way of meshing subplans (see section IV below). This does not represent a disagreement between us, for Bratman does not state his aim in the same way I have stated mine. His is introduced by way of an example of the sort of ‘shared intention’ he aims to provide an analysis of. Mine is introduced by way of a certain semantic reading of a plural action sentence. The notion of a shared intention is made for the notion of shared cooperative activity which Bratman discusses in (Bratman, 1992). See the last paragraph of section V for discussion of the difference between shared cooperative activity and collective intentional behavior more generally. Even
Charge ratio of cosmic-ray electrons

Charge ratio of cosmic ray electrons, examining excitation of baryon resonances in high energy collisions with no exchange of isospin
Synthesis and characterization of the quaternary scandium uranium selenide CsScUSe3(Se2)

Abstract The compound CsScUSe3(Se2) has been synthesized by the reaction of U, Sc, and Se in a CsCl flux at 1173 K. Its structure is composed of infinite [ ScUSe 5 − ] ∞ 2 sheets that are separated by Cs+ ions. The structure contains one Se22− unit per U. Accordingly, the formula is charge balanced with U4+ and Sc3+ as Cs1+Sc3+U4+(Se2−)3(Se22−). From magnetic susceptibility measurements the magnetic behavior of CsScUSe3(Se2) can be divided into three different regions: paramagnetic, T>TN; antiferromagnetic ordering, T
Perturbative Scattering Phase Shifts in One-Dimension: Closed-form results

Abstract A simple closed form expression is obtained for the scattering phase shift perturbatively to any given order in effective half-line one-dimensional problems. The result is a hierarchical scheme, expressible in quadratures, requiring only knowledge of the zeroth order solution and the perturbation potential.
Linearly Bounded Conjugator Property for Mapping Class Groups

Given two conjugate mapping classes f and g, we produce a conjugating element ω such that \({|\omega| \le K (|f| + |g|)}\), where | · | denotes the word metric with respect to a fixed generating set, and K is a constant depending only on the generating set. As a consequence, the conjugacy problem for mapping class groups is exponentially bounded.
Magnetically Driven Warping, Precession and Resonances in Accretion Disks

Interaction between an accretion disk and a magnetic star lies at the heart of the physics of a variety of astrophysical systems, including accreting neutron stars, white dwarfs and pre-main-sequence stars (e.g., Frank et al. 1992). The basic picture of disk—magnetosphere interaction was first outlined by Pringle & Rees (1972), following the discovery of accretion-powered X-ray pulsars. These are rotating, highly magnetized(B ti 1012G) neutron stars (NSs) that accrete material from a companion star, either directly from a stellar wind, or in the form of an accretion disk. The strong magnetic field disrupts the accretion flow at the magnetospheric boundary (typically at a few hundreds NS radii), and channels the plasma onto the polar caps of the NS. The magnetosphere boundary is located where the magnetic and plasma stresses balance, rrn_ qµ4/7(GMM2)-1/7, whereMand tt are the mass and magnetic moment of the central star,Mis the mass accretion rate,gis a dimensionless constant of order unity. In low-mass X-ray binaries containing weakly magnetized(B108G) NSs, the magnetosphere lies close to the stellar surface. In this case, complex field topology and general relativity can affect the determination of the magnetosphere boundary (e.g., Lai 1998). Similar magnetosphere—disk interaction also occurs in T Tauri stars (e.g., Hartmann 1998), where the stellar magnetic field(B103G) strongly affects the accretion flow, as well as in certain class (the so-called DQ Her stars or intermediate polars) of magnetic CVs.
Emerging patterns for engineered nanomaterials in the environment: a review of fate and toxicity studies

A comprehensive assessment of the environmental risks posed by engineered nanomaterials (ENMs) entering the environment is necessary, due in part to the recent predictions of ENM release quantities and because ENMs have been identified in waste leachate. The technical complexity of measuring ENM fate and transport processes in all environments necessitates identifying trends in ENM processes. Emerging information on the environmental fate and toxicity of many ENMs was collected to provide a better understanding of their environmental implications. Little research has been conducted on the fate of ENMs in the atmosphere; however, most studies indicate that ENMs will in general have limited transport in the atmosphere due to rapid settling. Studies of ENM fate in realistic aquatic media indicates that in general, ENMs are more stable in freshwater and stormwater than in seawater or groundwater, suggesting that transport may be higher in freshwater than in seawater. ENMs in saline waters generally sediment out over the course of hours to days, leading to likely accumulation in sediments. Dissolution is significant for specific ENMs (e.g., Ag, ZnO, copper ENMs, nano zero-valent iron), which can result in their transformation from nanoparticles to ions, but the metal ions pose their own toxicity concerns. In soil, the fate of ENMs is strongly dependent on the size of the ENM aggregates, groundwater chemistry, as well as the pore size and soil particle size. Most groundwater studies have focused on unfavorable deposition conditions, but that is unlikely to be the case in many natural groundwaters with significant ionic strength due to hardness or salinity. While much still needs to be better understood, emerging patterns with regards to ENM fate, transport, and exposure combined with emerging information on toxicity indicate that risk is low for most ENMs, though current exposure estimates compared with current data on toxicity indicates that at current production and release levels, exposure to Ag, nZVI, and ZnO may cause toxicity to freshwater and marine species.
Cobalt-based magnetic nanocomposites: fabrication, fundamentals and applications

Recently, magnetic nanocomposites (MNC) have aroused significant scientific and technological interests because their properties strongly rely on the interplay between those of the constituent components. Here, using three types of cobalt-based MNCs, we demonstrate how their physical behaviour, including thermal, electrical and magnetic, can be strongly affected by such interplays. First, using Aucore–Coshell nanoparticles (NPs), we demonstrate that their thermal stabilities are critically dependent on various boundaries and they structurally transform from the core–shells to the peanut structures via several intermediate states by a series of energy minimizations including the grain boundaries, Co/Au interface and strain. Second, the microstructures of the MNC are co-determined by the properties of the individual components, which in turn will strongly affect their overall properties. We illustrate this by a careful study of the electron transport in cobalt/poly (3-hexylthiophene, 2, 5-diyl) (P3HT) hybrid thin films, and show that they satisfy a fluctuation-induced tunnelling model that is strongly depended on their microstructures; moreover, a magnetoresistance in these thin films was also observed. Finally, the magnetic properties and phase stability of MNCs can also be strongly altered as a result of this interplay. Three phase transformations are observed in cobalt ferrofluids for T ~ 10–300 K, namely second order magnetic phase transformations (blocked–unblocked transition) at the blocking temperature of the magnetic NP, first order magnetic and structural phase transformations at the solvent melting temperature, TM, and second order premelting transformation at TPM < T < TM. These transformations show specific magnetic signatures in field-cool and zero-field-cool magnetization measurements and are qualitatively in agreement with predictions using M-spectrum theory.
Renormalized perturbation series of electrodynamics fromS-matrix theory

Electromagnetic processes are evaluated using extended unitarity and analyticity of the scattering amplitude. Assuminge2 to be small, a successive pole approximation of the unitarity relation and appropriate approximative analyticity assumptions to every order ine2 are shown to be equivalent to renormalized Feynman perturbation theory.
Preparing the information technology workforce for the new millennium

In an era when information technology (IT) is an integral part of society, many organizations are finding it difficult to hire adequate numbers of information technology personnel. Computer systems have permeated virtually every facet of organizations, creating a demand for individuals with IT skills at every level. The situation is complicated by the fact that finding personnel with the appropriate skills mix is even more problematic. As we move into the new millennium, IT roles are shifting at a rapidly increasing pace. Technical skills alone are not sufficient for success in the IT profession --- soft skills like communication, problem solving, and teamwork are increasingly important. Recognizing that no curriculum can provide all training needed by every employee in every position, the issue then becomes to identify which specific sets of knowledge, skills, and abilities (KSAs) are most important to IT organizations. This paper presents the findings of an initial case study undertaken to identify the necessary KSAs that can be used in the development of academic and industry training programs. The focus of this paper is on the findings for soft skill KSAs.
“Just so” neutrino oscillations are back

Abstract Recent evidence for oscillations of atmospheric neutrinos at Super-Kamiokande suggest, in the simplest see-saw interpretation, neutrino masses such that “just so” vacuum oscillations can explain the solar neutrino deficit. Super-K solar neutrino data provide preliminary support for this interpretation. We describe how the just-so signal – an energy dependent seasonal variation of the event rate, might be detected within the coming years and provide general arguments constraining the sign of the variation. The expected variation at radiochemical detectors may be below present sensitivity, but a significant modulation in the 7 Be signal could shed light on the physics of the solar core – including a direct measure of the solar core temperature.
Generalizations of a Laplacian-type equation in the Heisenberg group and a class of Grushin-type spaces

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Enhancing location privacy in wireless LAN through disposable interface identifiers: a quantitative analysis

The recent proliferation of wireless local area networks (WLAN) has introduced new location privacy risks. An adversary controlling several access points could triangulate a client's position. In addition, interface identifiers uniquely identify each client, allowing tracking of location over time. We enhance location privacy through frequent disposal of a client's interface identifier. While not preventing triangulation per se, it protects against an adversary following a user's movements over time. Design challenges include selecting new interface identifiers, detecting address collisions at the MAC layer, and timing identifier switches to balance network disruptions against privacy protection. Using a modified authentication protocol, network operators can still control access to their network. An analysis of a public WLAN usage trace shows that disposing addresses before reassociation already yields significant privacy improvements.
Probing the protostellar envelope around L1157: The dust and gas connection

We present observations of the Class 0 protostar L1157-mm using the Combined Array for Research in Millimeter-wave Astronomy (CARMA) in 3 mm dust continuum and N{sub 2}H{sup +} line emission. In the N{sub 2}H{sup +} line, we detect a large-scale envelope extended over a linear size of approx20,000 AU flattened in the direction perpendicular to the outflow. This N{sub 2}H{sup +} feature coincides with the outer envelope seen in the 8 mum extinction by Looney et al. Meanwhile, the dust continuum traces the compact, nearly spherical structure of the inner envelope, where N{sub 2}H{sup +} becomes depleted. This highly flattened N{sub 2}H{sup +} envelope also shows dynamical signatures consistent with gravitational infall in the inner region, but a slow, solid-body rotation at large scales. This flattened structure is not a rotationally supported circumstellar disk; instead, it resembles a prestellar core both morphologically and kinematically, representing the early phase of a Class 0 system. In this paper, we construct a simple model to interpret both the dust continuum and N{sub 2}H{sup +} emission and suggest a possible dynamical scenario for the overall properties of the envelope.
Gravitational radiation from a solid-crust neutron star

The relationship between the rapid rotation of the millisecond pulsar and gravitational radiation is addressed. By balancing gravitational radiation against the rate of rotational energy loss, it is found that if the effective triaxiality exceeds about 10 to the -9th, gravitational radiation alone would spin a millisecond pulsar down at a faster rate than the observed period derivative. It is shown that the effective triaxiality is much less than the maximum triaxiality, so that gravitational radiation is not likely to play a major role in the evolution of millisecond pulsars even in the absence of damping. Damping times for precession of the solid crust are estimated to be less than 2000 years.
A proper orthogonal decomposition method for nonlinear flows with deforming meshes

Abstract This paper presents a proper orthogonal decomposition (POD) method that uses dynamic basis functions. The dynamic functions are of a prescribed form and do not explicitly depend on time but rather on parameters associated with flow unsteadiness. This POD method has been developed for modeling nonlinear flows with deforming meshes but can also be applied to fixed meshes. The method is illustrated for subsonic and transonic flows in channels with fixed and deforming meshes. This method properly captured flow nonlinearities and shock motion for cases in which the classical POD method failed.
The mu and tau number of supernovae

Abstract The neutrino-nucleon cross section is slightly larger than that for ν −N . Therefore, ν will escape more quickly from core collapse supernovae leaving the star ν rich. A diffusion formalism is used to calculate the time evolution of the mu and tau lepton number densities. These quickly reach steady state equilibria. We estimate that a protoneutron star with a maximum temperature near 50 MeV will contain over 50% more ν μ and ν τ than ν μ and ν τ . Supernovae may be the only known systems with large mu and or tau lepton numbers.
Towards an Explicit Model of D-brane Inflation

We present a detailed analysis of an explicit model of warped D-brane inflation, incorporating the effects of moduli stabilization. We consider the potential for D3-brane motion in a warped conifold background that includes fluxes and holomorphically embedded D7-branes involved in moduli stabilization. Although the D7-branes significantly modify the inflaton potential, they do not correct the quadratic term in the potential, and hence do not cause a uniform change in the slow roll parameter eta. Nevertheless, we present a simple example based on the Kuperstein embedding of D7-branes, z1 = constant, in which the potential can be fine-tuned to be sufficiently flat for inflation. To derive this result, it is essential to incorporate the fact that the compactification volume changes slightly as the D3-brane moves. We stress that the compactification geometry dictates certain relationships among the parameters in the inflaton Lagrangian, and these microscopic constraints impose severe restrictions on the space of possible models. We note that the shape of the final inflaton potential differs from projections given in earlier studies: in configurations where inflation occurs, it does so near an inflection point. Finally, we comment on the difficulty of making precise cosmological predictions in this scenario. This is the companion paper to Baumann et al (2007 Phys. Rev. Lett. 99 141601).
Disposition of cefepime in the central nervous system of patients with external ventricular drains.

Study Objective. To assess central nervous system (CNS) penetration of cefepime in adults with external ventricular drains and to compare the achieved cerebrospinal fluid (CSF) concentrations with the usual minimum inhibitory concentrations (MICs) of common pathogens. Design. Open-label, prospective study. Setting. University-affiliated medical center. Patients. Seven patients with external ventricular drains and normal renal function (documented creatinine clearance > 60 ml/min) who received cefepime 2 g intravenously every 12 hours for treatment of nosocomial pneumonia. Intervention. Serial serum and CSF samples were obtained concurrently after the fourth dose during one dosing interval. Measurements and Main Results. The concentration-time profiles in serum and CSF were comodeled by using a two-compartment model with zero-order infusion to the central compartment. The CSF concentration-time profiles of the individual patients were compared with published MIC90 of common pathogens isolated in nosocomial meningitis. Our model reasonably characterized the disposition of cefepime in serum and CSF. Penetration into the CNS was 4–34% based on area under the curve and was 5–58% based on minimum concentration. Conclusion. Penetration of cefepime into the CNS was variable among the patients (4–34%) but appeared similar to that reported for other cephalosporins given to treat meningitis. The concentrations attained by most patients in this study were above the MIC90 of many common nosocomial organisms.
Simulation of wave propagation in three-dimensional random media

Quantitative error analyses for the simulation of wave propagation in three-dimensional random media, when narrow angular scattering is assumed, are presented for plane-wave and spherical-wave geometry. This includes the errors that result from finite grid size, finite simulation dimensions, and the separation of the two-dimensional screens along the propagation direction. Simple error scalings are determined for power-law spectra of the random refractive indices of the media. The effects of a finite inner scale are also considered. The spatial spectra of the intensity errors are calculated and compared with the spatial spectra of intensity. The numerical requirements for a simulation of given accuracy are determined for realizations of the field. The numerical requirements for accurate estimation of higher moments of the field are less stringent.
Absence of "ghost images" excludes large values of the cosmological constant

We used the 1.4 GHz NRAO NVSS survey to search for "ghost" images of radio sources, expected in cosmologies with a positive cosmological constant and positive space curvature. No statistically significant evidence for "ghost" images was found, placing constraints on the values of Λ, the space curvature or the duration of the radio-luminous phase of extragalactic radio sources.
An ASCA Study of the Supernova Remnant G39.2–0.3

We present the analysis of archival data from the Advanced Satellite for Cosmology and Astrophysics of the supernova remnant (SNR) G39.2-0.3. G39.2-0.3 has been sometimes characterized as a shell-like remnant in the literature, but our high-energy imaging and spectral analysis show the unambiguous composite nature of the remnant. We find that part of the contribution to the X-ray emission of G39.2-0.3 is distinctly nonthermal, best described by a power law with a photon index (2.53). The region of emission is consistent with a point source (extension consistent with the point-spread function of the detector at the off-axis angle of the observation) and is roughly defined by a circle of radius ~4'. A second contribution comes from a thermal component, which contributes flux primarily at low energies. Despite the absence of any pulsed emission detected from the compact source, we argue that the emission is most probably due to a rotating compact object that is powering the detected synchrotron nebula within the SNR.
Regio- and diastereoselective decarboxylative coupling of heteroaromatic alkanes.

Allylic esters of heteroaromatic alkanes undergo facile palladium-catalyzed decarboxylative coupling. The resulting C−C bond is formed with high diastereoselectivity and high regioselectivity for coupling at the more substituted allyl terminus. It is proposed that this unusual combination of selectivities results from a tandem allylation/aza-Cope rearrangement sequence. After allylation, decarboxylative dearomatization produces an intermediate for the aza-Cope rearrangement. The subsequent aza-Cope rearrangement occurs under mild conditions because it is driven by rearomatization.
Valuing Emerging Market Equities—A Pragmatic Approach Based on the Empirical Evidence

Combining the theory with the empirical evidence, I propose a pragmatic approach to estimating the cost of equity for industry groups operating in African, Asian, and Latin American emerging markets, and high-risk European markets. My approach has two building blocks: (1) use of the U.S.-based Capital Asset Pricing Model (CAPM) with a beta that is designed to represent industry (instead of individual company) risk; and (2) an adjustment of the U.S.- based CAPM that involves assigning a certain proportion -- from as little as 35% to as much as 100% -- of a given country’s political risk to a specific industry. My empirical work finds that ADR returns are strongly correlated with: (1) SP and (2) the corresponding country’s changes in CDS spreads, capturing country risk. Moreover, I find that the coefficient in the CDS spread is strongly negatively correlated with the ADR’s P/E multiple suggesting that certain industries are more exposed to political risk than others.Visually analyzing my empirical results, regarding country-risk exposure, I group industries into low (consumer discretionary and staples), medium (health care, industrials, information technology, materials, telecommunications, and utilities), and high-exposure categories (energy and financials). Synthesizing these results, I propose cost of equity estimations based on: (1) an industry beta, (2) the country’s CDS spread, and (3) the industry’s country-risk exposure. To cite two examples, whereas a utility operating in South Korea might have a cost of equity of less than 8%, an energy company in Russia might have a cost of equity as high as 16.25%.
Reducing estimation risk in optimal portfolio selection when short sales are allowed

The issue of estimation risk is of particular interest to the decision-making processes of portfolio managers who use long–short investment strategies. Accordingly, our paper explores the question of whether a VaR constraint reduces estimation risk when short sales are allowed. We find that such a constraint notably decreases errors in estimates of the expected return, standard deviation, and VaR of optimal portfolios. Furthermore, optimal portfolios in the presence of the constraint are substantially closer to the ‘true’ efficient frontier than those in its absence. Finally, we provide VaR bounds and confidence levels for the constraint that lead to the best out-of-sample performance. Copyright © 2008 John Wiley & Sons, Ltd.
On the Limitations of Predictions of the Dynamic Response of Machines with Clearance Connections

The results of experimental and analytical studies of the dynamic response of machines with flexible links and connection clearances are presented. These results suggest that both a large amount of variability and high sensitivity to small parameter changes and operating conditions are inherent properties of the dynamic response of such systems. This work indicates that the accuracy of dynamic force predictions given by computer simulations for such systems may be fundamentally limited, and therefore such simulations should be used with care in system design.
Microwave Assisted Synthesis of Bridgehead Alkenes

A new, concise method to synthesize triene precursors for the type 2 intramolecular Diels−Alder reaction has been developed. Microwave irradiation of the trienes provides a convenient method for the synthesis of bridgehead alkenes. Higher yields, shorter reaction times, and lower reaction temperatures provide a general and efficient route to this interesting class of molecules.
The facile fragmentation of trifluoroacetyl groups to nitriles

Abstract Trifluoroacetyl groups attached to a carbon atom devoid of hydrogen undergo facile, high-yield conversion to nitriles by reaction with MeAlClNH 2 , followed by KOtBu, in a “one-pot” reaction sequence.
Two-Dimensional Network Simulation of Diffusion-Driven Coarsening of Foam Inside a Porous Medium

Abstract In order to use foams in subsurface applications, it is necessary to understand their stability in porous media. Diffusion-driven coarsening of a stationary or nonflowing foam in a porous medium results in changing gas pressures and a coarsening of the foam texture. A two-dimensional network simulation has been created that predicts the behavior of foam in a porous medium by physically specifying the locations of all the lamellae in the system and by solving the complete set of Young–Laplace and diffusion equations. An hourglass approximates the shape of the pores, and the pore walls are considered to be highly water wet. A singularity arises in the system of differential algebraic equations due to the curvature of the pore walls. This singularity is a signal that the system must undergo oscillations or sudden lamellar rearrangements before the diffusion process can continue. Newton–Raphson iteration is used along with Keller's method of arc-length continuation and a new jump resolution technique to locate and resolve bifurcations in the system of coupled lamellae. Gas bubbles in pore throats are regions of encapsulated pressure. As gas is released from these bubbles during diffusion, the pressure of the bubbles in the pore bodies increases. When the pressure increase is scaled by the characteristic Young–Laplace pressure, the equilibrium time for the diffusion process is scaled by the ratio of the square of the characteristic length to the gas diffusivity and two dimensionless groups. One describes the ease with which gas can diffuse through a lamella, and the second represents the amount of gas encapsulated within the pore throats initially. Given this scaling, the resulting plots of pressure versus time and normalized lamellae positions versus time are universal for all system sizes and characteristics. This is true as long as the initial lamella distribution is the same in each case.
Small systems: when does thermodynamics apply?

The validity of using temperature to describe quantitatively the state of excitation of an isolated nucleus is examined. The problem arises because of the small number of particles in a nucleus. As a consequence, it is possible to construct a heat bath and so fix the temperature. Another definition is used that leads to an uncertainty in the measured temperature which tends to zero as the number of particles in the system increases. The emphasis is on the nuclear problem but it is presumed that similar considerations apply to other small isolated systems such as single molecules, atomic clusters containing two to several hundred atoms, helium droplets, etc. >