cssi/SciSciGPT-SciSciNet huggingface dataset:
Emission-Line Properties of 3CR Radio Galaxies. III. Origins and Implications of the Velocity Fields

We present the results of an analysis of the large-scale velocity fields of the ionized gas associated with powerful radio galaxies. Long-slit spectra of 52 objects provide a sample of resolved velocities that span a wide range of redshifts and radio and emission-line luminosities. Line widths reaching 1000 km s-1 and resolved velocity fields with amplitudes of up 1500 km s-1 are found on scales from 10 to 100 kpc in the environments of radio galaxies at redshifts greater than 0.5. The global velocities and FWHM are of comparable amplitudes in the FR II sources, while the FR I sources have FWHM values that are larger than their resolved velocity fields. We find evidence for systematically larger line widths and velocity field amplitudes at z > 0.6. Several of the largest amplitude systems contain two galaxies with small projected separations. All of the greater than 1000 km s-1 systems occur in objects at z > 0.6 and all have comparable radio and [O II] sizes. There is a weak correlation of off-nuclear line widths and velocity field with the ratio of the radio and emission-line sizes, but it is of low statistical significance and there is a very large dispersion. The change in properties at redshifts above z ~ 0.6 could reflect a difference in environments of the host galaxies, with the hosts inhabiting higher density regions with increasing redshift (e.g., Hill & Lilly). The mass of ionized gas and the apparent enclosed dynamical mass are correlated and both increase steeply with redshift and/or radio power. The origin of the velocities remains uncertain. The data do not require jet-gas interactions to explain the kinematics and superficially are slightly more consistent with gravitational origins for the bulk of the kinematics. If the line width reflects the underlying gravitational potential, the observed FWHM traces the velocity dispersion of the host galaxy or its surrounding group or cluster. The highest velocities seen then point to interesting environments for intermediate- and high-redshift radio galaxies. Turbulent interactions with the expanding radio source as the origin of the kinematics are certainly not ruled out. In the jet interaction scenario, the maximum velocities seen in the nebula can be used to constrain the density of the preshock gas to be roughly ne > 0.6 cm-3.
Cosmic ray positron and negatron spectra between 20 and 800 MeV measured in 1974

A balloon-borne spark chamber magnetic spectrometer was used to measure separate spectra of positrons and negatrons in two flights during summer, 1974. The total electron flux is about 0.3 m(-2) s(-1) sr(-1) MeV(-1) between 70 and 800 MeV, and increases toward lower energies. The positron spectrum decreases sharply toward lower energies from a value of about 0.08 m(-2) s(-1) sr(-1) MeV(-1) at 650 MeV, and only upper limits are obtained for positrons below 200 MeV. At energies above 180 MeV, the spherically symmetric Fokker-Planck equation provides reasonable fits to both the positron and total electron data. At energies below 180 MeV the data are consistent with a continuation of the same diffusion coefficient and local source of negatrons, or a change in the diffusion coefficient to a constant value.
Th microanalysis using fission tracks

(1971). Th microanalysis using fission tracks. Radiation Effects: Vol. 7, No. 3-4, pp. 285-287.
Transition Metal-Free Catalytic Synthesis of 1,5-Diaryl-1,2,3-Triazoles

1,5-Diarylsubstituted 1,2,3-triazoles are formed in high yield from aryl azides and terminal alkynes in DMSO in the presence of catalytic tetraalkylammonium hydroxide. The reaction is experimentally simple, does not require a transition-metal catalyst, and is not sensitive to atmospheric oxygen and moisture.
Solar Flash Desalination Under Hydrostatically Sustained Vacuum

A new desalination scheme has been proposed. The system consists of a saline water tank, a concentrated brine tank, and a fresh water tank placed on ground level plus an evaporator and a condenser located several meters above the ground. The evaporator-condenser assembly, or flash chamber, is initially filled with saline water that later drops by gravity, creating a vacuum above the water surface in the unit without a vacuum pump. The vacuum is maintained by the internal hydrostatic pressure balanced by the atmospheric pressure. The ground tanks are open to the atmosphere, while the flash chamber is insulated and sealed to retain both heat and vacuum. A theoretical simulation of the proposed model was carried out using a detailed model built by employing the fundamental physical and thermodynamic relationships to describe the process and was complimented by reliable empirical correlations to estimate the physical properties of the involved species and the operational parameters of the proposed system. The simulation results show that running the system at higher ,flash temperatures with a fixed flash chamber size will result in faster vacuum erosion leading to less overall evaporation.
The associated map of the nonabelian Gauss-Manin connection

The Gauss-Manin connection for nonabelian cohomology spaces is the isomonodromy flow. We write down explicitly the vector fields of the isomonodromy flow and calculate its induced vector fields on the associated graded space of the nonabelian Hogde filtration. The result turns out to be intimately related to the quadratic part of the Hitchin map.
Climate treaties and approaching catastrophes

Abstract If the threshold that triggers climate catastrophe is known with certainty, and the benefits of avoiding catastrophe are high relative to the costs, treaties can easily coordinate countries' behavior so as to avoid the threshold. Where the net benefits of avoiding catastrophe are lower, treaties typically fail to help countries cooperate to avoid catastrophe, sustaining only modest cuts in emissions. These results are unaffected by uncertainty about the impact of catastrophe. By contrast, uncertainty about the catastrophic threshold normally causes coordination to collapse. Whether the probability density function has “thin” or “fat” tails makes little difference.
Transferring process equipment innovations from user‐innovators to equipment manufacturing firms

Product users are not usually thought of as product innovators. We have found, however, that 67|X% of the significant process equipment innovations in the two fields of semiconductor manufacture and electronic subassembly manufacture were in fact developed by equipment users rather than equipment manufacturers. Our analysis of the process by which these user innovations are transferred to the first firm to manufacture them commercially shows three major patterns: 46|X% transferred by multiple user-manufacturer interactions; 21|X% transferred via a direct purchase order from the inventive user; 8|X% manufactured by a user firm for commercial sale. A final 25|X%, we found, were apparently not transferred, but were reinvented by the equipment manufacturing firm. Inventive user firms and adopting equipment manufacturing firms are characterized, and the implications of our findings discussed.
Performance Evaluation of Service Territories

Field service support is important for certain products, such as computer systems and copiers, for which service performance has a significant impact on market share. In this paper, the problem of field service operations and its important characteristics are described. Models are developed to assist the field service manager in the evaluation of performance of a given service territory with heterogeneous machines scattered typically, nonuniformly over a region, repaired by a traveling serviceman. Given the probability distributions of machine uptimes and repair times, and travel times between machine locations, models are developed to approximate the overall travel time distribution. This is used in existing queueing models to determine the performance measures, such as mean downtime per machine and server utilization. The results of the models are tested by simulation and observed to provide good estimates for the measures of interest. These models are eventually intended to help in making decisions on territory design and staffing levels.
Photochemical hydrogen evolution via singlet-state electron-transfer quenching of zinc tetra(N-methyl-4-pyridyl)porphyrin cations in a zeolite L based system

Molecular electron transport chains composed EDTA, zinc tetra (N-methyl-4-pyridyl)porphyrin(ZnTMPyP/sup 4 +/), and methylviologen (MV/sup 2 +/), spatially organized by 1 ..mu.. diameter zeolite L particles, were studied. MV/sup 2 +/ ion exchanges into zeolite L to a maximum loading of 2.5-3.0 x 10/sup -4/ mol/g of zeolite, while the bulkier ZnTMPyP/sup 4 +/ adsorbs only onto the outer surface in approximately monolayer (8 x 10/sup -6/ mol/g) quantities. At pH 4.0, EDTA/sup 2 -/ is strongly adsorbed onto the ZnTMPy/sup 4 +/-coated surface. When the composite is prepared from internally platinized zeolite L particles, hydrogen is evolved photochemically from water in pH 4.0, 2 x 10/sup -3/ M EDTA solution. The rate of hydrogen evolution depends on the MV/sup 2 +/ loading, no H/sub 2/ being evolved below 1.5 x 10/sup -4/ mol MV/sup 2 +//g (ca. 0.4 MV/sup 2 +/ ion per large cavity). ZnTMPyP/sup 4 +/ shows a biphasic fluorescence decay when adsorbed on the zeolite L surface. The rapidly decaying component has a lifetime varying from <20 ps to 150 ps; the inverse lifetime (fluorescence decay rate) shows the same dependence on MV/sup 2 +/ loading as the hydrogen evolution rate. The slowly decaying fluorescence component andmore » the time-resolved triplet-triplet absorbance are invariant with MV/sup 2 +/ loading. These observations are explained in terms of single-state electron-transfer quenching of ZnTMPyP/sup 4 +/ by MV/sup 2 +/. The triplet excited state reactivity of ZnTMPyP/sup 4 +/ is suppressed by a 200-mV positive shift of its redox potentials caused by adsorption onto the zeolite surface.« less
Velocity Field Characteristics of a Swirling Flow Combustor

Data for reacting and nonreacting flows obtained by laser anemometry in a swirl combustor are reported and discussed. The combustor consists of two confined, concentric swirling jets. The central jet flow is premixed methane/air; the annular jet flow is air. The two flow conditions investigated are flow rotation in the same direction (coswirl) and in opposite directions (counterswirl). A closed, central recirculation zone is observed in both swirl conditions for reacting flow, but only in counterswirl for nonreacting flow. Large, anisotropic velocity fluctuations are observed in high shear regions and in the vicinity of the recirculation zone. Mechanisms for swirl-generated recirculation zone formation are discussed.
Functional status and therapeutic intensity during inpatient rehabilitation

The objective of this study was to describe the relationships between functional status at discharge and intensity of therapies received during inpatient medical rehabilitation. The sample was comprised of 140 patients with traumatic brain injury and 106 patients with spinal cord injury at eight hospitals that subscribe to the Uniform Data System for Medical Rehabilitation. Data included linear measures of motor and cognitive ability derived from the Functional Independence Measure at admission to and discharge from rehabilitation. Multiple regression was used to predict intensity of therapies, discharge motor and cognitive function, the extent to which potential functional gains were achieved, and the efficiency of gains. Intensities of occupational, physical, and speech therapies were not significant predictors of outcomes for either group, controlling linearly for admission function, psychology intensity, length of stay, onset to admission interval, age, and interrupted stays. Only intensity of psychology services seemed to have any relation to functional gain (in cognition for patients with traumatic brain injury). The apparent lack of benefit related to intensity of therapies may be due to factors such as spontaneous recovery, goals not measured by the Functional Independence Measure, limited modulation of therapy intensity according to likely patient responsiveness, or therapies focused on impairment or other goals rather than disability. We suggest that efficiently staged rehabilitation should vary the intensity and nature of services according to patients' functional status, impairments, comorbid conditions, and other clinical factors.
A Sharper Estimate on the Betti Numbers of Sets Defined by Quadratic Inequalities

In this paper we consider the problem of bounding the Betti numbers, b i (S), of a semi-algebraic set S⊂ℝ k defined by polynomial inequalities P 1≥0,…,P s ≥0, where P i ∈ℝ[X 1,…,X k ], s<k, and deg (P i )≤2, for 1≤i≤s. We prove that for 0≤i≤k−1, $$\begin{array}{lll}\displaystyle b_{i}(S)&\displaystyle \le&\displaystyle \frac{1}{2}+(k-s)+\frac{1}{2}\cdot \sum_{j=0}^{\mathit{min}\{s+1,k-i\}}2^{j}{{s+1}\choose j}{{k}\choose j-1}\\[18pt]&\displaystyle \le &\displaystyle \frac{3}{2}\cdot\biggl(\frac{6ek}{s}\biggr)^{s}+k.\end{array}$$ This improves the bound of k O(s) proved by Barvinok (in Math. Z. 225:231–244, 1997). This improvement is made possible by a new approach, whereby we first bound the Betti numbers of non-singular complete intersections of complex projective varieties defined by generic quadratic forms, and use this bound to obtain bounds in the real semi-algebraic case.
Asymmetric Synthesis of the Aminocyclitol Pactamycin, a Universal Translocation Inhibitor

An asymmetric total synthesis of the aminocyclopentitol pactamycin is described. The title compound is delivered in 15 steps from 2,4-pentanedione. Critical to this approach was the exploitation of a complex symmetry-breaking reduction strategy to assemble the C1, C2, and C7 relative stereochemistry within the first four steps of the synthesis. Multiple iterations of this reduction strategy are described, and a thorough analysis of stereochemical outcomes is detailed. In the final case, an asymmetric Mannich reaction was developed to install a protected amine directly at the C2 position. Symmetry-breaking reduction of this material gave way to a remarkable series of stereochemical outcomes leading to the title compound without recourse to nonstrategic downstream manipulations. This synthesis is immediately accommodating to the preparation of structural analogs.
Nonabelian Poincaré duality after stabilizing

We generalize the nonabelian Poincare duality theorems of Salvatore in [Sal01] and Lurie in [Lur09] to the case of not necessarily grouplike E_n-algebras (in the category of spaces). We define a stabilization procedure based on McDuff's "brining points in from infinity" maps from [McD75]. For open connected parallelizable n-manifolds, we prove that, after stabilizing, the topological chiral homology of M with coefficients in an E_n-algebra A, is homology equivalent to Map^c(M,B^n A), the space of compactly supported maps to the n-fold classifying space of A. The two models of topological chiral homology used in this paper are Andrade's model from [And10] and Salvatore's from [Sal01].
Palladium-catalyzed synthesis of diarylmethanes: exploitation of carbanionic leaving groups.

A novel route to the synthesis of diarylmethanes via a Pd-catalyzed α-arylation of benzyl ketones is reported. By harnessing the inherent reactivity of enolates, it is possible to circumvent the need for a transmetalating reagent such as boron for the coupling. Additionally, the two phenyl rings of the intermediate are exploited to stabilize the high-energy carbanionic leaving group in a straightforward synthesis.
Prandtl Number Effect on Bénard Convection in Porous Media

A numerical study of buoyance-driven two-dimensional convection in a fluid-saturated horizontal porous layer is reported emphasizing the nonlinear inerital effect on heat transport. The Forchheimer-Brinkman-Darcy-Boussinesq formulation and a single energy equation for the volume-average temperature are used. Closure to the wavenumber selection problem is sought through a criterion based on the Glansdorff and Prigogine theory of nonequilibrium thermodynamics. Good agreement with laboratory data and the analogy with th Rayleigh-Benard problem are corroborative facts which justify smililar non-Darcian formulations and demonstrate the role of the quadratic inertial terms in decreasing the mean convective heat transfer across the layer.
Cooperation between Noncanonical Ras Network Mutations

Cancer develops after the acquisition of a collection of mutations that together create the cancer phenotype. How collections of mutations work together within a cell and whether there is selection for certain combinations of mutations are not well understood. We investigated this problem with a mathematical model of the Ras signaling network, including a computational random mutagenesis. Modeling and subsequent experiments revealed that mutations of the tumor suppressor gene NF1 can amplify the effects of other Ras pathway mutations, including weakly activating, noncanonical Ras mutants. Furthermore, analyzing recently available, large, cancer genomic data sets uncovered increased co-occurrence of NF1 mutations with mutations in other Ras network genes. Overall, these data suggest that combinations of Ras pathway mutations could serve the role of cancer "driver." More generally, this work suggests that mutations that result in network instability may promote cancer in a manner analogous to genomic instability.
TRANSPLANTATION IMMUNITY OF GESTATIONAL ORIGIN IN INFANT RATS.

Comparison of the survival times of homografts of BN skin on 3-day-old Lewis rats born of mothers of the same isogenic strain with those of BN grafts on infant Lewis hosts that had developed in an F1 (Lewis x BN) hybrid, gave no evidence of maternally induced tolerance as a result of development in an antigenically alien environment. On the contrary, the significantly shorter median survival time of the grafts on the hybrid-derived Lewis group suggests that sensitization had occurred as a consequence of natural exposure during gestation to small numbers of maternal cells.
The Synchrotron Shock Model Confronts a "Line of Death" in the BATSE Gamma-Ray Burst Data

The synchrotron shock model (SSM) for gamma-ray burst emission makes a testable prediction: that the observed low-energy power-law photon number spectral index cannot exceed -2/3 (where the photon model is defined with a positive index: $dN/dE \propto E{alpha}$). We have collected time-resolved spectral fit parameters for over 100 bright bursts observed by the Burst And Transient Source Experiment on board the {\it Compton Gamma Ray Observatory}. Using this database, we find 23 bursts in which the spectral index limit of the SSM is violated, We discuss elements of the analysis methodology that affect the robustness of this result, as well as some of the escape hatches left for the SSM by theory.
The Radius Distribution of Planets around Cool Stars

We calculate an empirical, non-parametric estimate of the shape of the period-marginalized radius distribution of planets with periods less than 150 days using the small yet well-characterized sample of cool (T_(eff) < 4000 K) dwarf stars in the Kepler catalog. In particular, we present and validate a new procedure, based on weighted kernel density estimation, to reconstruct the shape of the planet radius function down to radii smaller than the completeness limit of the survey at the longest periods. Under the assumption that the period distribution of planets does not change dramatically with planet radius, we show that the occurrence of planets around these stars continues to increase to below 1 R_⊕, and that there is no strong evidence for a turnover in the planet radius function. In fact, we demonstrate using many iterations of simulated data that a spurious turnover may be inferred from data even when the true distribution continues to rise toward smaller radii. Finally, the sharp rise in the radius distribution below ~3 R_⊕ implies that a large number of planets await discovery around cool dwarfs as the sensitivities of ground-based transit surveys increase.
Novel free radical ring-expansion reactions

Abstract A novel free radical initiated ring expansion of haloalkyl β-keto esters is described. Following alkylation of the β-keto ester with the appropriate dihalide, the resulting halide is treated at reflux with tri-n-butyltin hydride. Rearrangement to the homologated γ-keto ester occurs smoothly. An oxy radical intermediate is proposed for the reaction.
Apprenticeship for Teaching: Professional Development Issues Surrounding the Collaborative Relationship between Teachers and Paraeducators.

Abstract A sociocultural approach to teacher education supports an apprenticeship model in which social relationships mediate learning through collaborative meaningful activity. This model can be found in the collaborative relationship between paraeducators and teachers. Within this model, the roles of learners and more competent others can potentially be interchangeable as paraeducators, often members of the communities, assist teachers in developing culturally responsive instruction. This paper reports on the relationship between Latino paraeducators and the teachers with whom they worked. Findings suggest that collaboration is impacted by power differences, limited opportunity for interaction, and teacher constraints.
On neutrino masses and mixings from extra dimensions

Abstract In the framework of a Kaluza-Klein type theory with the Standard Model fields localized on a 4-dimensional section while gravity propagates in a full 4+ δ -dimensional space-time, we examine a mechanism of naturally small neutrino mass generation through couplings of the Standard Model singlet fermion(s) living also in the full space-time. A numerical study is carried out on the charged current universality constraint from the ratio of pion decay partial widths. The bounds obtained on the fundamental mass scale could be stringent.
Groundwater discharge and gully formation on martian slopes

Abstract Young gullies and gully deposits on walls of martian craters have been cited as evidence that liquid water flowed on the surface of Mars relatively recently. Effects of variable environmental conditions at the surface of Mars are modeled and applied to the case of groundwater emergence from shallow aquifers to investigate whether groundwater is a viable source to enable the erosion of these gullies. The model includes detailed treatment of ice growth in the aquifer. Model results indicate that groundwater discharge can be maintained under the current environmental conditions if the aquifer permeability is like that of terrestrial gravel or higher, if the aquifer is 350 K or warmer, or if the aquifer is a brine with a freezing point depressed to 250 K or below. Groundwater discharge cannot be maintained for the conservative case of a cold, pure water, semi-pervious aquifer. Cold (275 K) pure water pervious (gravel) aquifers, warm (350 K) pure water semi-pervious aquifers, and cold (275 K) CaCl2 brine semi-pervious aquifers all exhibit a dependence of discharge on season, latitude and slope orientation in our modeling. Seasonal, latitudinal and azimuthal discharge variations are strongest for cold CaCl2 brine semi-pervious aquifers, with discharges from this aquifer type favoring equator-facing slopes at mid and high southern latitudes. At all latitudes and slope azimuths under our nominal conditions, the cold pure water pervious aquifer, the cold pure water semi-pervious aquifer and the cold CaCl2 brine semi-pervious aquifer all freeze completely shortly after the simulations are started. Discharge restarts in the summer for the cold pure water pervious aquifer and the cold brine aquifer, but discharge does not restart for the cold pure water semi-pervious aquifer. The warm pure water semi-pervious aquifer maintains daily seeps throughout the year at all but high latitudes. In the case of the cold pure water pervious aquifer, approximately 500,000 m3 of water could be discharged from a mid-latitude, 150-m thick aquifer with a 20-m wide seepage face orientated towards the equator or the pole after a single undermining-induced event before ice growth seals the seepage face. For a brine semi-pervious aquifer with the same dimensions, 200–300 m3 of water could be released from a mid-latitude 20-m wide equator-facing seepage face before the fresh exposure is sealed for the fall and winter seasons. Our results do not rule out groundwater emergence as a means of creating some recent gullies, but they indicate that rather special and perhaps unusual conditions would be required.
Stopped-flow studies of the N ⇌ F transition in serum albumin

Abstract Stopped-flow studies of the refolding of iodoacetamide-blocked bovine serum albumin from the acid unfolded “F” state have been performed. If the protein is incubated with low concentrations of perchlorate anion then the refolding kinetics follow a simple first-order process. The dependence on pH of both the amplitude of the observed transients and the measured rate constants indicates that the N ⇌ F transition is highly cooperative. The results are consistent with the postulated multidomain structure of albumin which has been developed as a result of both sequence work and a variety of physical studies.
Acoustic tomography at basin scales and clock errors

A basin-scale acoustic tomography simulation is carried out for the northeast Pacific Ocean to determine the accuracy with which time must be kept at the sources when clocks at the receivers are accurate. A sequential Kalman filter is used to estimate sound-speed fluctuations and clock errors. Sound-speed fluctuations in the simulated ocean are estimated from an eddy-resolving hydrodynamic model of the Pacific forced by realistic wind fields at daily resolution from 1981-1993. The model output resembles features associated with El Nino and the Southern Oscillation, as well as many other features of the ocean's circulation. Using a Rossby-wave resolving acoustic array of four fixed sources and twenty drifting receivers, the authors find that the percentage of the modeled ocean's sound-speed variance accounted for with tomography is 92% at 400-km resolution, regardless of the accuracy of the clocks. Clocks which drift up to hundreds of seconds of error or more for a year do not degrade tomographic images of the model ocean. Tomographic reconstructions of the sound-speed field are insensitive to clock error primarily because of the wide variety of distances between the receivers from each source. Every receiver "sees" the same clock error from each source, regardless of section length, but the sound-speed fluctuations in the modeled ocean cannot yield travel times which lead to systematic changes in travel time that are independent of section length. The Kalman filter is thus able to map the sound-speed field accurately in the presence of large errors at the source's clocks.
The role of the invariant line in the search for an optimum interphase boundary by O-lattice theory

The purpose of the present communication is threefold: to demonstrate that the interphase boundary can be shown analytically to have the lowest energy parameter P of all possible O-lattice boundaries; to explain the significance of the calculated 0.05-micron rotation around (0001) and its relationship to the more general principle of an invariant line; to show that the optimum interphase boundaries are generally different for coherent and semicoherent precipitates having the same OR with the matrix.
Tunneling between two semiconductors with localized electrons: Can it reveal the Coulomb gap?

It is shown that the voltage dependence of the tunneling conductance between two lightly doped semiconductors, which are separated by a large area tunneling barrier, can reveal the high energy part of the Coulomb gap if the barrier is thick enough. At barrier thickness smaller than the average distance between impurities no Coulomb gap feature can be found. This happens because such tunneling is sensitive to very rare shortest pairs of occupied and empty states localized at opposite sides of the barrier, whose density of states in this limit has no Coulomb gap. Small area tunneling contacts are also discussed. It is shown that the tunneling conductance of a point-like contact exponentially grows with the applied voltage. This dependence does not permit a direct measurement of the Coulomb gap.
Optically Projected X-Ray Images from a Sealed Chamber Ionography System

Ionography, which is currently receiving much attention, is an x-ray image recording system in which the detector is a thin ion-ization chamber usually containing a heavy, high pressure (10 atmospheres), gas. Ions formed by X rays in the gas are swept across the chamber by an electric field onto a thin insulating film to form a charge image. In current systems the chamber is then depressurized, the film removed, and its charge image made visible using powder or liquid toner. An alternative method for making the charge images visible is herein described which overcomes the mechanical problems of film and gas handling of present techniques. An added advantage is that it produces instantaneous bright, stored, projected images which offer the potential of fluoroscopic ionography. In the new technique charges are collected onto a thin clear deformable layer of oil or soft elastomer coating a front surface mirror in the chamber. Electrostatic forces between the surface charges and the conducting mirror cause imagewise deformations which are immediately made visible on an external screen by a Schlieren optical projection system using light which enters and leaves the chamber through a high pressure glass window. Images, with resolution better and sensitivity close to film/screen methods, have been obtained.
LIMITS ON PRODUCTION OF NARROW BAND PHOTONS FROM INVERSE COMPTON SCATTERING

In using the inverse Compton scattering (ICS) interaction as a high brilliance, short wavelength radiation source, one collides two beams, one an intense laser, and the other a high charge, short pulse electron beam. In order to maximize the flux of photons from ICS, one must focus both beams strongly, which implies both use of short beams and the existence of large angles in the interaction. One aspect of brilliance is the narrowness of the wavelength band emitted by the source. This paper explores the limits of ICS-based source brilliance based on inherent wavelength broadening effects that arise due to focal angles, laser energy density, and finite laser pulse length effects. It is shown that for a nominal 1% desired bandwidth, that one obtains approximately one scattered photon per electron in a head-on collision geometry.
On Preserving a B+L Asymmetry Produced in the Early Universe

Abstract One of the most efficient mechanisms for producing the baryon asymmetry of the Universe is the decay of scalar condensates in a SUSY GUT as was first suggested by Affleck and Dine. We show that given a large enough asymmetry, the baryon number will be preserved down to low temperatures even if B − L = 0, because the baryon number carrying scalars from Bose condensates that give the W a mass. We derive the conditions on the condensate needed to suppress electroweak sphaleron interactions which would otherwise drive the baryon asymmetry to zero when B − L = 0.
The nature of emission from optical breakdown induced by pulses of fs and ns duration

Spectral emission from optical breakdown in the bulk of a transparent dielectric contains information about the nature of the breakdown medium. We have made time resolved measurements of the breakdown induced emission caused by nanosecond and femtosecond infrared laser pulses. We previously demonstrated that the emission due to ns pulses is blackbody in nature allowing determination of the fireball temperature and pressure during and after the damage event. The emission due to femtosecond pulse breakdown is not blackbody in nature; two different spectral distributions being noted. In one case, the peak spectral distribution occurs at the second harmonic of the incident radiation, in the other the distribution is broader and flatter and presumably due to continuum generation. The differences between ns and fs breakdown emission can be explained by the differing breakdown region geometries for the two pulse durations. The possibility to use spectral emission as a diagnostic of the emission region morphology will be discussed.
Ecological Imperialism: The Biological Expansion of Europe, 900-1900

People of European descent form the bulk of the population in most of the temperate zones of the world - North America, Australia and New Zealand. The military successes of European imperialism are easy to explain; in many cases they were a matter of firearms against spears. But as Alfred Crosby explains in his highly original and fascinating book, the Europeans' displacement and replacement of the native peoples in the temperate zones was more a matter of biology than of military conquest.
Multinary intermetallics from molten Al. Synthesis of SmNiAl4Ge2 and YNiAl4Ge2. Possible spin frustration in separated triangular Sm3+ layers

SmNiAl4Ge2 crystallizes from molten Al containing Sm, Ni, and Ge. The compound crystallizes in the rhomohedral space group R3m with a = 4.1121(6) A, c = 31.109(6) A, and V = 455.5(1) A3. The YNiAl4Ge2 analogue is also stable. The crystal structure consists of layers of [NiAl4Ge2]3- separated by monolayers of hexagonally close-packed Sm3+ ions. The Ni atoms are surrounded by eight Al atoms in the structure. Each Sm atom has an octahedral environment of six Ge atoms. The magnetism of SmNiAl4Ge2 is unusual, possibly reflecting the presence of geometrical spin frustration. The magnetization exhibits a well-defined hysteresis loop, without signs of ferromagnetism. It also exhibits irreversibility in the field-cooled and zero-field-cooled magnetization but without the typical characteristic spin glass behavior.
Serum Anti-Müllerian Hormone Concentrations Are Elevated in Oligomenorrheic Girls without Evidence of Hyperandrogenism

Context: Serum anti-Mullerian hormone (AMH) levels are significantly elevated in adolescents with polycystic ovary syndrome (PCOS) compared to normal controls. Whether adolescents with oligomenorrhea have elevated AMH levels is unknown. Objective: This study was performed to assess serum AMH levels in oligomenorrheic (OLIGO) girls without evidence of hyperandrogenism. Design: This was a prospective study comparing AMH levels in OLIGO, PCOS, and normal control adolescents. Setting: The study was conducted through four tertiary academic medical centers. Participants: The study groups were comprised of OLIGO (n = 24), PCOS (n = 153), and normal adolescent girls (n = 39), as well as PCOS (n = 73) and normal adult women (n = 36). Interventions: In each subject, serum AMH levels were assessed in the early to midfollicular phases for regularly menstruating subjects and on an arbitrary day for OLIGO or PCOS subjects. Main Outcome Measure(s): Basal serum AMH levels were assessed among OLIGO, PCOS, and normal girls, in addition to PCOS and normal women. Results: OLIGO girls had serum AMH levels (5.33 ± 0.47 ng/ml) that were significantly greater than the normal adolescents (3.05 ± 0.31 ng/ml) and adults (2.33 ± 0.22 ng/ml), but similar to values seen in the PCOS adolescents (5.28 ± 0.26 ng/ml) and adults (6.36 ± 0.47 ng/ml). Obese adolescents and PCOS women had significantly lower AMH levels compared to lean controls (P < 0.02). Conclusion: In OLIGO adolescents, elevated serum AMH levels suggest increased antral follicle number similar to that observed in girls with PCOS.
A Transition Closure Model for Predicting Transition Onset

A unified approach which makes it possible to determine the extent and onset of transition in one calculation is presented. It treats the laminar fluctuations in a manner similar to that used in describing turbulence. As a result, the complete flowfield can be calculated using existing CFD codes and without the use of stability codes. The method is validated by comparing the results for flat plates, airfoils, and infinite swept wings with available experiments. In general, good agreement is indicated.
False-name-proof voting with costs over two alternatives

In open, anonymous settings such as the Internet, agents can participate in a mechanism multiple times under different identities. A mechanism is false-name-proof if no agent ever benefits from participating more than once. Unfortunately, the design of false-name-proof mechanisms has been hindered by a variety of negative results. In this paper, we show how some of these negative results can be circumvented by making the realistic assumption that obtaining additional identities comes at a (potentially small) cost. We consider arbitrary such costs and apply our results within the context of a voting model with two alternatives.
Heat transfer of buried pipe for heat pump application

It is generally felt that the application of line source theory for ground coil design usually resulted in excessive overdesign. It was anticipated that in order for the ground coil heat pump systems to be economically competitive with other residential heating and cooling systems, ground coil overdesign had to be kept to a minimum. A new ground coil model was derived, which based on energy balance rather than the traditional line source theory. It was aimed to more accurately predict the operation of ground coils. It is the intention of this study to compare this ground coil model with models based on line source theory, a simple line source model and a modified line source model, by using them to simulate the same field test data for both summer and winter ground coil operations. The results indicated that for winter coil operation, the new model predicted the coil liquid exit temperature less than 2{degrees}C maximum deviation from the measured values, with an average deviation less than 1{degree}C. The modified line source model had an average deviation of more than 1.5{degrees}C. For summer operation, all models under-predicted the measured soil temperatures because the effect of thermal backfill material was not includedmore » in the models. The new model still predicted the test results better than the other two models.« less
Bimetallic catalysts for hydrogen generation

Research interest in bimetallic catalysts is mainly due to their tunable chemical/physical properties by a number of parameters like composition and morphostructure. In catalysis, numerous bimetallic catalysts have been shown to exhibit unique properties which are distinct from those of their monometallic counterparts. To meet the growing energy demand while mitigating the environmental concerns, numerous endeavors have been made to seek green and sustainable energy resources, among which hydrogen has been identified as the most promising one with bimetallic catalysts playing important roles. This tutorial review intends to summarize recent progress in bimetallic catalysts for hydrogen production, specifically focusing on that of reforming technologies as well as the relevant processes like water-gas shift (WGS) and CO preferential oxidation (PROX), and emphasizing on the fundamental understanding of the nature of catalytic sites responsible for generating high purity hydrogen and minimizing carbon monoxide formation. Meanwhile, some important synthesis and characterization methods of bimetallic catalysts developed so far are also summarized.
Acyclic nucleoside/nucleotide analogues with an imidazole ring skeleton.

Syntheses of a few acyclic nucleoside and acyclic nucleoside phosphonate analogues containing an imidazole ring have been reported. These analogues include methyl 1-(2-hydroxyethoxymethyl)imidazole-4,5-dicarbo-xylate (1), 4,5-dicarbamoyl-1-(2-hydroxyethoxymethyl)imidazole (2), 4,5-dicya-no-1-(2-hydroxyethoxymethyl)imidazole (4), Methyl 1-(2-bromoethoxymethyl)- imidazole-4,5-dicarboxylate (7), 4,5-dicyano-(2-bromoethoxymethyl)imidazole (8), and Methyl 1-(2-phosphonomethoxyethyl)imidazole (10). Also reported are a few potential prodrugs of the above compounds, including the acetyl derivatives 5 and 6 (of 1 and 4, respectively), and the diethyl phosphonate ester 9 (of 10). In addition, the corresponding benzyl-protected precursors 11 and 12 (of 1 and 4, respectively), along with their common hydrolysis product, 1-(2-benzyloxy-ethoxymethyl)-4,5-imidazoledicarboxylic acid (3), are reported. Another potential prodrug included in the list is 1-(2-acetoxyethyl)-4,5-dicyanoimidazole (15). The compounds were screen...
Asymmetric Synthesis of α-Branched Allylic Amines by the Rh(I)-Catalyzed Addition of Alkenyltrifluoroborates to N-tert-Butanesulfinyl Aldimines

The first Rh(I)-catalyzed addition of alkenylboron reagents to imines is described. The Rh(I)-catalyzed addition of potassium alkenyltrifluoroborate salts to both aromatic and aliphatic N-tert-butanesulfinyl aldimines proceeds in good yields (up to 97%) and with very high diastereoselectivities (95:5 to >99:1). This new method enables the general and efficient asymmetric synthesis of the important class of α-branched allylic amines from readily available and stable starting materials.
Admission Control to Minimize Rejections

Admission control (call control) is a well-studied online problem. We are given a fixed graph with edge capacities, and must process a sequence of calls that arrive over time, accepting some and rejecting others in order to stay within capacity limitations of the network. In the standard theoretical formulation, this problem is analyzed as a benefit problem: The goal is to devise an online algorithm that accepts at least a reasonable fraction of the maximum number of calls that could possibly have been accepted in hindsight. This formulation, however, has the property that even algorithms with optimal competitive ratios (typically O(log n) where n is the number of nodes) may end up rejecting the vast majority of calls even when it would have been possible in hindsight to reject only very few. In this paper, we instead consider the goal of approximately minimizing the number of calls rejected. This is much more appropriate for settings in which rejections are intended to be rare events. In order to avoid t...
Differential Impacts of Structural and Cyclical Unemployment on Mortgage Default and Prepayment

The Great Recession (the fourth quarter of 2007 through the second quarter of 2009) has been characterized by high rates of foreclosures and unemployment. Using a sample of community reinvestment loans, we examine the impact of structural unemployment and cyclical unemployment on mortgage terminations (default and prepayment). We find that mortgage default and prepayment are more sensitive to changes in the structural component of the local unemployment rate than in the cyclical component. In addition, depending on whether structural unemployment rates are high or low, borrowers and lenders react differently to the incentives to terminate a loan.
Optical diagnostics for high-speed flows

Abstract Since 2000 there has been a revolution in diagnostics of high-speed air flows. The foundations for this revolution were laid over the past few decades, but with the development of new short pulse and pulse burst laser technologies, higher laser powers and higher pulse energies, new high-speed cameras, better laser control and improved detection and laser delivery methodologies, many very effective new capabilities have been developed. Newly developed methods for molecular tagging velocimetry provide high fidelity visualization of transport properties and may be extended to simultaneous temperature measurements. Rapid field imaging with frequency tunable pulse burst lasers shows instantaneous flow structure and complex boundary and mixing interactions. Extending these pulse burst concepts to swept volumetric imaging is very promising for full volumetric data collection. Fast wavelength modulation spectroscopy follows real-time flow variation, and three-dimensional particle imaging extends particle imaging velocimetry to volumetric data acquisition.
The characterization problem for Hoare logics

Research by myself and by others has shown that there are natural programming language control structures that are impossible to describe adequately by means of Hoare axioms. Specifically, we have shown that there are control structures for which it is impossible to obtain axiom systems that are sound and relatively complete in the sense of Cook. These constructs include procedures with procedure parameters under standard ALGOL 60 scope rules and coroutines in a language with parameterless recursive procedures. A natural question to ask is whether it is possible to characterize those programming languages for which sound and complete proof systems can be obtained. For a wide class of programming languages and interpretations, it can be shown that P has a sound and relatively complete proof system for every expressive interpretation iff the halting problem for language P is decidable for all finite interpretations. Nevertheless, we are still far from a completely satisfactory characterization of the programming languages that can be axiomatized in this manner. The proof system that is generated in proving the above result does not have the property of being ‘syntax-directed’, which is distinctive of the Hoare axioms. Moreoever, theoretical considerations suggest that good axioms for total correctness may exist for a wider spectrum of languages than for partial correctness. In this paper we discuss these questions and others that still need to be addressed before the characterization problem can be considered solved.
Ranks of elliptic curves in families of quadratic twists

We show that the unboundedness of the ranks of the quadratic twists of an elliptic curve is equivalent to the divergence of certain infinite series.
Effect of dienophile activating group on the stereoselectivity of the intramolecular diels-alder reaction

Abstract The stereoselectivity of the intramolecular Diels-Alder reactions of terminally activated trienes 4 and 5 increases as the dienophile activating group is changed along the series CONR2
Carbamate dianions: Generation and alkylation of α-oxo carbanions

Abstract Dianions from simple N-tbutyl benzylic-type carbamates are readily formed with alkyllithium bases and undergo alkylation with a variety of electrophiles. Both secondary and tertiary α-oxo carbanions are easily accessible. DIBAL cleavage of the carbamate provides a high yield, general synthesis of alkylated benzylic alcohols.
A Generalized Expert System Shell for Implementing Mechanical Design Applications: Review, Introduction, and Fundamental Concepts

The foundations for an expert system shell for implementing mechanical design applications are presented in this paper. The shell supports facilities for knowledge acquisition, quasireactive planning, design evaluation, and subjective explanation. The underlying philosophy of each of these facilities and some preliminary implementation issues are discussed. A brief summary of a recent research effort and its implications on the development of a generalized expert system shell for implementing mechanical design applications are also presented
Magnetically-responsive self assembled composites

This tutorial review summarizes the recent advances on the self assembly of magnetic nanoparticles into one-, two-, and three-dimensional architectures using synthetic polymers and biopolymers. The materials have unique stimuli-responsive behavior that emerge in response to internal and external magnetic fields. For example, magnetic fields can be used to elicit a magnetic response from the materials, whether the material rearranges in response to the external field, or provides information regarding the local environment of the nanoparticles. These materials hold great promise for applications ranging from data storage to nanomedicine.
Intermolecular [8+2] cycloaddition reactions of 2H-3-methoxycarbonylcyclohepta[b]furan-2-one with vinyl ethers: an approach to bicyclo[5.3.0]azulene derivatives.

Substituted bicyclo[5.3.0]azulene compounds are synthesized by intermolecular [8+2] cycloaddition reactions of lactone 1 with vinyl ethers—acetal decomposition products—are described. The reactions were found to be temperature and solvent dependent.