cssi/SciSciGPT-SciSciNet huggingface dataset:
Modeling all dialogue system participants to generate empathetic responses.

Abstract A dialogue system between an expert system and its users is described which combines two recent hypothesis, First, that the dialogue system should explicitly model both the person directly interacting with the dialogue system (the agent) and the person reasoned about by the expert system (the patient) in order to communicate meaningfully with both people. Second, that a dialogue system can model the domain-related beliefs, preferences and concerns of both its users and generate responses empathetic to both. This dialogue system is called serum , standing for ‘System for Empathetic Responses with User Models’. serum generates natural-language responses about attribute values of domain objects, via three transformations. First, the system converts properties of the agent and patient, and domain knowledge, into a pragmatic objective like empathy. Second, serum converts the pragmatic objectives into surface structure cues like object emphasis and level of technicality. Finally, serum converts the surface structure cues to realize text that is natural, appropriately technical and emotionally empathetic. serum is demonstrated in describing tests and treatments for lung disease in AIDS patients, a sensitive domain where empathetic responses may be needed.
Efficient Nucleophilic Fluoromethylation and Subsequent Transformation of Alkyl and Benzyl Halides Using Fluorobis(phenylsulfonyl)methane

An efficient methodology for the nucleophilic fluoromethylation of alkyl and benzyl halides using alpha-fluoro-alpha-(phenylsulfonyl)methane (1) as a highly versatile reagent is reported. Using benzyl halides, stereospecific one-pot synthesis of alpha-fluorovinyl compounds such as alpha-fluorostyrylsulfones, alpha-fluorocinnamates, and alpha-fluorochalcones has been achieved. The methodology has been extended toward the synthesis of alpha-substituted fluoroalkane derivatives using selective reductive desulfonylation conditions.
First-, second-, and third-order finite-volume schemes for diffusion

In this paper, we present constructions of first-, second-, and third-order schemes for diffusion by the method introduced in Nishikawa (2007) [10]. In this method, numerical schemes for diffusion are constructed by advection schemes via an equivalent hyperbolic system. This paper demonstrates that the method enables straightforward constructions of diffusion schemes for finite-volume methods on unstructured grids. In particular, it is demonstrated that a robust first-order upwind scheme leads to a robust first-order diffusion scheme, and a high-order advection scheme leads to a high-order diffusion scheme. It is shown that first-, second-, and third-order schemes are capable of producing first-, second-, and third-order accurate solution gradients, respectively, on irregular grids. Accuracy, Fourier stability, and the energy stability of the developed schemes are discussed. A new hyperbolic diffusion system having virtually no source terms is also introduced to simplify the construction of the third-order scheme. Numerical results are presented for regular and irregular triangular grids to demonstrate not only the superior accuracy but also the accelerated steady convergence over a traditional method.
Optical klystron configuration for a high gain x-ray free-electron laser

Abstract We present theory and numerical simulations of the performance of an x-ray free-electron laser in the amplified spontaneous emission mode with an optical klystron undulator configuration. This devicecan produce picosecond pulses of high brightness with a significantly shorter undulator than a conventional FEL.
ESTIMATION OF AVERAGE TREATMENT EFFECTS WITH MISCLASSIFICATION

This paper considers identification and estimation of the effect of a mismeasured binary regressor in a nonparametric or semiparametric regression, or the conditional average effect of a binary treatment or policy on some outcome where treatment may be misclassified. Failure to account for misclassification is shown to result in attenua- tion bias in the estimated treatment effect. An identifying assumption that overcomes this bias is the existence of an instrument for the binary regressor that is conditionally independent of the treatment effect. A discrete instrument suffices for nonparametric identification. THIS PAPER PROVIDES CONDITIONS for identification and estimation of the av- erage effect, conditioned on covariates, of a binary treatment, program, or pol- icy on a scalar outcome when treatment may be misclassified. More generally, what is provided is an estimator of the effect of a binary regressor in a con- ditional mean regression (which may also include other regressors) when the binary regressor is observed with error. This equals the conditional average treatment effect given a weak unconfoundedness assumption. Misclassification occurs when a binary variable (the treatment indicator) is measured with error, that is, some units are reported to have received treat- ment when they actually have not, and vice versa. For example, in a returns to schooling analysis the outcome could be wages, the binary variable could be attaining a college degree, and misclassification could arise from school tran- script reporting errors. See, e.g., Kane and Rouse (1995) and Kane, Rouse, and Staiger (1999). Bollinger (1996) considers misclassification of union status in wage equations. If treatment is a job training program, misclassification may arise if individuals assigned to the program fail to attend or if those not as- signed obtain training elsewhere. Similarly, for medical treatment, individuals assigned a drug might fail to take it and those assigned a placebo might obtain treatment from another source. More generally, misclassification describes any binary variable that is sometimes mismeasured. This paper first shows that misclassification causes attenuation bias in esti- mated treatment effects, analogous to the attenuation bias of classically mis- measured variables in linear regression models. Additional assumptions on
Sun, earth, and sky

The Sun is enveloped by a hot, tenuous million-degree corona that expands to create a continuous solar wind that sweeps past all the planets and fills the heliosphere. The solar wind is modulated by strong gusts that are initiated by powerful explosions on the Sun, including solar flares and coronal mass ejections. This dynamic, invisible outer atmosphere of the Sun is currently under observation with the soft X-ray telescope aboard the Yohkoh spacecraft, whose results are presented. We also show observations from the Ulysses spacecraft that is now passing over the solar pole, sampling the solar wind in this region for the first time. Two other spacecraft, Voyager 1 and 2, have recently detected the outer edge of the invisible heliosphere, roughly halfway to the nearest star. Magnetic solar activity, the total radiative output from the Sun, and the Earth's mean global surface temperature all vary with the 11-year sunspot cycle in which the total number of sunspots varies from a maximum to a minimum and back to a maximum again in about 11 years. The terrestrial magnetic field hollows out a protective magnetic cavity, called the magnetosphere, within the solar wind. This protection is incomplete, however, so the Sun feeds an unseen world of high-speed particles and magnetic fields that encircle the Earth in space. These particles endanger spacecraft and astronauts, and also produce terrestrial aurorae. An international flotilla of spacecraft is now sampling the weak points in this magnetic defense. Similar spacecraft have also discovered a new radiation belt, in addition to the familiar Van Allen belts, except fed by interstellar ions instead of electrons and protons from the Sun.
Measured microwave emission and scattering in vegetation canopies

Reflecting metal screens were placed beneath vegetation of three types to allow measurement of the brightness temperature of the vegetation cover alone. A two-frequency radiometer (wavelengths: 11.1 and 5.88 cm) was used to measure the emission from the vegetation, nod a theoretical model involving a loss term and a scattering albedo was fitted to the measured temperatures. Passive and active microwave measurements were also made on fields immediately adjacent to the “screened” fields. Emission and backscattering were measured for these fields under two conditions: 1) with full vegetation cover, and 2) with vegetation removed. Using the same theoretical model and the calculated values for absorption and scattering derived from the screened fields, the effect of the vegetation cover on the soil emission was predicted. The predicted full-canopy temperatures were then compared to those measured. The values for loss and scattering in the vegetation canopy were used in another model to predict the effect of vegetation on backscattering from the soil surface. Again, the predicted backscattering from the vegetation canopy was compared with the measured values of σ°.
Carbonylative Cross-Coupling of ortho-Disubstituted Aryl Iodides. Convenient Synthesis of Sterically Hindered Aryl Ketones

A mild and general protocol for the carbonylative cross-coupling of sterically hindered ortho-disubstituted aryl iodides is reported. Carbonylative Suzuki-Miyaura couplings of a variety of aryl boronic acids provide an array of substituted biaryl ketones in modest to excellent yield. A carbonylative Negishi coupling that utilizes alkynyl nucleophiles is also described.
Optimization of time delay systems using parameter imbedding

A new computational approach for optimization of linear time-delay (differential-difference) systems with quadratic indices is presented. The method utilizes parameter imbedding, and transforms the advanced-delayed type two point boundary value form of necessary conditions to a sequence of conventional non-delayed linear boundary value problems. The method leads to a truncated Maclaurin series approximation for the optimum control.
Synthesis of β-hydroxy-α-amino acids by aldol condensation using a chiral phase transfer catalyst

Abstract Efficient, nearly racemic syntheses of β-hydroxy-α-amino acids by aldol condensations between t -butyl (diphenylmethy]ene)glycinate 2 and aldehydes under phase transfer catalytic conditions in the presence of the chiral catalyst N-benzylcinchoninium chloride are described.
Realistic gluino axion model consistent with supersymmetry breaking at the TeV scale

The recently proposed model of using the dynamical phase of the gluino to solve the strong CP problem is shown to admit a specific realization in terms of fundamental singlet superfields, such that the breaking of supersymmetry occurs only at the TeV scale, despite the large axion scale of 109-1012 GeV. Phenomenological implications are discussed.
In search of α-eliminations of carbon induced by sixteen electron iron: photolysis and thermolysis of derivatives of phenyl substituted cyclobutanes and cyclopropanes

Abstract Photolysis of dicarbonyl(η 5 -cyclopentadienyl)(1-phenylcyclobutane-1-carbonyl)iron is proposed to give the hydride complex Ph(cyclobutenyl)Fe(Cp)-(CO)H which dissociates to 1-phenylcyclobutene and FpH (Fp = η 5 -cyclopentadienyldicarbonyliron). The FpH complex can oxidatively add to the sixteen electron acyl or σ complexes (Ph(cyclobutyl)-C(O)FeCp(CO) and Ph(cyclobutyl)FeCp(CO) respectively) to produce phenylcyclobutane and 1-phenylcyclobutane carboxaldehyde. Photolysis of dicarbonyl(η 5 -cyclopentadienyl)(1-phenylcyclopropyl-1-carbonyl)iron gives a σ complex with no further reaction. Substitution of CO with PPh 3 and thermolysis produced a centrally substituted π-allyl complex. In neither the cyclobutyl nor the cyclopropyl case did the reactions give isolable carbene complexes; apparently the phenyl substituent does not provide adequate stabilization of the carbene complex to allow its detection or isolation.
The efficacy of transvaginal sonographic screening in asymptomatic women at risk for ovarian cancer.

Abstract Objective. The purpose of this study was to determine the efficacy of annual transvaginal sonography (TVS) as a screening method for ovarian cancer. Methods. Annual TVS screening was performed on 14,469 asymptomatic women from 1987 to 1999. Eligibility criteria included (1) all women ≥ 50 years of age and (2) women ≥ 25 years of age with a family history of ovarian cancer. Ovarian volume was calculated using the prolate ellipsoid (length × height × width × 0.523). An abnormal sonogram was defined by (1) an ovarian volume >10 cm 3 in postmenopausal women or >20 cm 3 in premenopausal women or (2) a papillary or complex tissue projection into a cystic ovarian tumor. All women with abnormal TVS had a repeat sonogram in 4–6 weeks. Patients with a persistently abnormal second screen had a serum CA-125 determination, tumor morphology indexing, and Doppler flow sonography, and were advised to have surgical tumor removal. Results. One hundred eighty patients with persisting TVS abnormalities underwent exploratory laparoscopy or laparotomy. Seventeen ovarian cancers were detected: 11 Stage I, 3 Stage II, and 3 Stage III. Only three patients with Stage I cancers had a palpable ovarian mass on clinical examination. All patients with Stage I and II ovarian cancer are alive without recurrence 1.8–9.8 years (median, 4.5 years) after diagnosis. Two of the three Stage III patients have died of disease: one at 4.3 years and one at 7.7 years after detection. Four patients developed ovarian cancer within 12 months of a negative scan (FN): 2 Stage II, 2 Stage III. Three of these patients are alive with no evidence of disease 0.4, 1.9, and 5.5 years after diagnosis, and 1 patient has died of disease 0.7 years after diagnosis. Four patients developed ovarian cancer more than 12 months following a normal screen. All 4 presented clinically with Stage III disease. Two of these patients have died of disease and two patients are alive 1.5 and 2.1 years after diagnosis. TVS screening was associated with the following statistical variables: sensitivity, 81%; specificity, 98.9%; positive predictive value (PPV), 9.4%; and negative predictive value (NPV), 99.97%. After 46,113 screening years, there have been 3 ovarian cancer deaths in the annually screened population and 2 ovarian cancer deaths in women receiving less than annual screening. The survival of ovarian cancer patients in the annually screened population was 95.0 ± 4.9% at 2 years and 88.2 ± 8.0% at 5 years. Excluding all cases of nonepithelial or borderline epithelial malignancies, the survival of patients with ovarian cancer in the annually screened population was 92.9 ± 6.9% at 2 years and 83.6 ± 10.8% at 5 years. Conclusions. (1) TVS screening, when performed annually, is associated with a decrease in stage at detection and a decrease in case-specific ovarian cancer mortality. (2) TVS screening does not appear to be effective in detecting ovarian cancer in which ovarian volume is normal.
IL-11 PROTECTS HUMAN MICROVASCULAR ENDOTHELIUM FROM ALLOINJURY IN VIVO BY INDUCTION OF SURVIVIN EXPRESSION

IL-11 can reduce tissue injury in animal models of inflammation but the mechanism(s) is unknown. When C.B-17 SCID/beige mice bearing human skin grafts are injected i.p. with human PBMC allogeneic to the donor skin, infiltrating T cells destroy human microvessels by day 21. Intradermal injection of human IL-11 (500 ng/day) delays the time course of graft microvessel loss without reducing the extent of T cell infiltration. Protective actions of IL-11 are most pronounced on day 15. IL-11 has no effect on T cell activation marker, effector molecule, cytokine expression, or endothelial ICAM-1 expression. IL-11 up-regulates the expression of survivin, a cytoprotective protein, in graft keratinocytes and endothelial cells. Topical application of survivin antisense oligonucleotide down-regulates survivin expression in both cell types and largely abrogates the protective effect of IL-11. We conclude that in this human transplant model, IL-11 exerts a cytoprotective rather than anti-inflammatory or immunomodulatory effect mediated through induction of survivin.
Synthesis and anti-HIV activity of l-2′-fluoro-2′,3′-unsaturated purine nucleosides

Abstract The synthesis of 9-(2,3-dideoxy-2-fluoro- l -glycero-pent-2-eno-furanosyl)adenine and -hypoxanthine has been accomplished by direct condensation of silylated 6-chloropurine with key intermediates 8 , which were prepared starting from 2,3-O-isopropylidene- l -glyceraldehyde. The synthesized nucleosides were evaluated against HIV-1 in vitro in primary human lymphocytes (PMB cells). It was found that β- l -Fd4A 12 exhibited moderately potent anti-HIV activity (EC 50 1.5 μM).
Bridged bibenzimidazolium salts and their conversion to ureaphanes

Abstract The reduction of N,N′-polymethylene bridged, 2,2′-bibenzimidazolium salts with tetrakis (dimethylamino)ethylene in air provides ureaphanes whose conformations are dependent upon the length of the bridging chain.
An adiabatic demagnetization refrigerator for infrared bolometers

Adiabatic demagnetization refrigerators have been built and installed in small portable liquid helium cryostats to test the feasibility of this method of cooling infrared bolometric detectors to temperatures below 0.3 K. Performance has been achieved which suggests that bolometer temperatures of 0.2 K can be maintained for periods of approximately 60 hours. Applications to sensitive infrared detection from ground-based telescopes and space satellites are discussed. Design data are given which permit the evaluation of refrigerator performance for a variety of design parameters.
The Carathéodory–Fejér–Pisarenko Decomposition and Its Multivariable Counterpart

When a covariance matrix with a Toeplitz structure is written as the sum of a singular one and a positive scalar multiple of the identity, the singular summand corresponds to the covariance of a purely deterministic component of a time-series whereas the identity corresponds to white noise-this is the Caratheacuteodory-Fejeacuter-Pisarenko (CFP) decomposition. In the present paper we study multivariable analogs for block-Toeplitz matrices as well as for matrices with the structure of state-covariances of finite-dimensional linear systems (which include block-Toeplitz ones). To this end, we develop theory which addresses questions of existence, uniqueness and realization of multivariable power spectra, possibly having deterministic components. We characterize state-covariances which admit only a deterministic input power spectrum, and we explain how to realize multivariable power spectra which are consistent with singular state covariances via decomposing the contribution of the singular part. We then show that multivariable decomposition of a state-covariance in accordance with a "deterministic component + white noise" hypothesis for the input does not exist in general. We finally reinterpret the CFP-dictum and consider replacing the "scalar multiple of the identity" by a covariance of maximal trace which is admissible as a summand. The summand can be either (block-)diagonal corresponding to white noise or have a "short-range correlation structure" corresponding to a moving average component. The trace represents the maximal variance/energy that can be accounted for by a process at the input (e.g., noise) with the aforementioned structure, and this maximal solution can be computed via convex optimization. The decomposition of covariances and spectra according to the range of their time-domain correlations is an alternative to the CFP-dictum with potentially great practical significance
The α2-adrenergic receptor agonist, clonidine, reduces alcohol drinking in alcohol-preferring (P) rats

Abstract Evidence suggests that noradrenergic signaling may play a role in mediating alcohol-drinking behavior in both rodents and humans. We have investigated this possibility by administering clonidine to alcohol-drinking rats selectively bred for alcohol preference (P line). Clonidine is an α 2 -adrenergic receptor agonist which, at low doses, inhibits noradrenergic signaling by decreasing norepinephrine release from presynaptic noradrenergic neurons. Adult male P rats were given 24 h access to food and water and scheduled access to a 15% (v/v) alcohol solution for 2 h daily. Rats received intra-peritoneal (IP) injections with clonidine (0, 10, 20, 40, or 80 μg/kg body weight [BW], 10–11 rats/treatment group) once/day at 30 min prior to onset of the daily 2 h alcohol access period for 2 consecutive days. Clonidine, in doses of 40 or 80 μg/kg BW, significantly reduced alcohol intake on both days of treatment ( p p 1 -adrenergic receptor antagonist, prazosin, decreases voluntary alcohol drinking in alcohol-preferring rats, but suggests that effects of clonidine may not be specific for alcohol. The results suggest that although activation of the noradrenergic system plays an important role in mediating voluntary alcohol drinking, care is needed in selecting which drugs to use to suppress central noradrenergic signaling in order to maximize the selectivity of the drugs for treating alcohol-use disorders.
Improved time-dependent flowfield solution for solid rocket motors

A model of the time-dependent velocity field in solid rocket motors is derived analytically for an oscillatory field that is subject to steady sidewall injection. The oscillatory pressure amplitude is assumed to be small by comparison to the mean pressure. The mathematical approach includes solving the momentum equation governing the rotational flow using separation of variables and multiple scales. This requires identifying scales at which unsteady inertia, convection, and diffusion are significant. A composite scale is obtained that combines three disparate scales. The time-dependent axisymmetric solution obtained incorporates the effects of unsteady inertia, viscous diffusion, and the radial and axial convection of unsteady vorticity by Culick's mean flow components (Culick, F. E. C., Rotational Axisymmetric Mean Flow and Damping of Acoustic Waves in a Solid Propellant Rocket, AIAA Journal, Vol. 4, No. 8, 1966, pp. 1462-1464). The resulting agreement with tbe numerical solution to the momentum equation is remarkable. The uncertainty in a short analytical expression is found to be smaller than the injection Mach number, which represents the error associated with the mathematical model itself. The multiple-scales solution agrees extremely well with Flandro's recent flowfield solution (Flandro, G. A., On Flow Turning, AIAA Paper 95-2730, July 1995). The present solution has the advantage of being shorter, more manageable in extracting quantities of interest, and capable of showing the significance of physical parameters on the solution.
Extrasolar Refractory-Dominated Planetesimals: an Assessment

Previously published observations of 60 externally polluted white dwarfs show that none of the stars have accreted from intact refractory-dominated parent bodies composed mainly of Al, Ca, and O, although planetesimals with such a distinctive composition have been predicted to form. We propose that such remarkable objects are not detected by themselves because, unless they are scattered outward from their initial orbit, they are engulfed and destroyed during the star's asymptotic giant branch evolution. As yet, there is at most only weak evidence supporting a scenario where the composition of any extrasolar minor planet can be explained by blending of an outwardly scattered refractory-dominated planetesimal with an ambient asteroid.
Persistence of activity in threshold contact processes, an “Annealed approximation” of random Boolean networks

We consider a model for gene regulatory networks that is a modification of Kauffmann's J Theor Biol 22 (1969), 437–467 random Boolean networks. There are three parameters: $n = {\rm the}$ **image** number of nodes, $r = {\rm the}$ **image** number of inputs to each node, and $p = {\rm the}$ **image** expected fraction of 1'sin the Boolean functions at each node. Following a standard practice in thephysics literature, we use a threshold contact process on a random graph on n nodes, in which each node has in degree r, to approximate its dynamics. We show that if $r\ge 3$ **image** and $r \cdot 2p(1-p)>1$ **image** , then the threshold contact process persists for a long time, which correspond to chaotic behavior of the Boolean network. Unfortunately, we are only able to prove the persistence time is $\ge \exp(cn^{b(p)})$ **image** with $b(p)>0$ **image** when $r\cdot 2p(1-p)> 1$ **image** , and $b(p)=1$ **image** when $(r-1)\cdot 2p(1-p)>1$ **image** . © 2011 Wiley Periodicals, Inc. Random Struct. Alg., 2011 © 2011 Wiley Periodicals, Inc.
The massive fermion phase for the U(N) Chern-Simons gauge theory in D=3 at large N

We explore the phase structure of fermions in the U(N) Chern-Simons Gauge theory in three dimensions using the large N limit where N is the number of colors and the fermions are taken to be in the fundamental representation of the U(N) gauge group. In the large N limit, the theory retains its classical conformal behavior and considerable attention has been paid to possible AdS/CFT dualities of the theory in the conformal phase. In this paper we present a solution for the massive phase of the fermion theory that is exact to the leading order of ‘t Hooft’s large N expansion. We present evidence for the spontaneous breaking of the exact scale symmetry and analyze the properties of the dilaton that appears as the Goldstone boson of scale symmetry breaking.
An econometric analysis of the intertemporal general-equilibrium approach to exchange rate and current account determination

Abstract This paper attempts the econometric implementation of a monetary, intertemporal general-equilibrium model of exchange rate and current account determination in a small open economy. The reduced form of the model comprises a statement of the permanent income hypothesis of consumption and the rational expectations extension of the monetary approach to exchange rate determination. The model is estimated using full-information-maximum-likelihood methods and quarterly data over the recent flexible exchange rate period on the UK and US economies. The empirical findings suggest that the model shows considerable promise in explaining the exchange rate and consumption side of current account behavior. Some results are, however, suggestive of omitted considerations and extensions of the model for future research are indicated.
Propane on Titan

We present the first observations of propane (C_3H_8) on Titan that unambiguously resolve propane features from other numerous stratospheric emissions. This is accomplished using a R = λ/δλ ≈ 10^5 spectrometer (the Texas Echelon Cross Echelle Spectrograph) to observe propane's ν_(26) rotation-vibration band near 748 cm^(-1). We find a best-fit fractional abundance of propane in Titan's stratosphere of (6.2 ± 1.2) × 10^(-7) in the altitude range to which we are sensitive (90-250 km or 13-0.24 mbar).
Optical Properties of Amorphous ZnO, CdO, and PbO Nanoclusters in Solution

The authors prepared ZnO, CdO, and PbO rock salt-coordinated and ZnO quartzite-coordinated nanoclusters with a microemulsion method in the AOT reverse micelle. X-ray and electron beam diffraction techniques indicate that all have amorphous structures. The similarity of the UV-visible absorption and photoluminescence spectra at room temperature for ZnO, CdO, and PbO rock salt-coordinated nanoclusters indicates that they are all similar in electronic structure. All prepared nanosystems show strong emission in the visible region, and the emission features depend on the wavelength of the excitation. This phenomenon is considered as a result of localization of the electronic state due to the amorphous structure of nanocluster and surface capping. Time-resolved photoluminescence studies on ZnO, CdO, and PbO nanoclusters were performed. The carrier lifetimes near the band-tail are in the sub-and nanosecond time ranges with different characteristics from that of bulk amorphous semiconductors and nanocrystals. The observed properties can be explained in terms of quantum confinement, structural disorder, and surface polarization.
An internal cusp reflector for an evacuated tubular heat pipe solar thermal collector

Abstract This study involves the optical analysis of a slightly concentrating, symmetric cusp reflector inside a tubular glass envelope with a cylindrical heat pipe as the solar absorber. The basic design features of this non-tracking, evacuated, modular collector and the principles of heat removal are shown in Figs. 1 and 2. Differential equations of the cusp reflector optics, given the geometrical restrictions in Figs. 1 and 2, are derived, and solutions for the largest possible aperture inside a given diameter envelope and acceptance angle are presented. As an extension of the same study, the optical efficiency of a single collector tube has been simulated by means of a Monte Carlo Ray-Tracing Program. For a concentration ratio of 1.15, the flux distribution around the heat pipe is computed as a function of incidence angle. In addition, the impact of mirror defects and absorber misalignment on the optical performance are analyzed.
The Classical and Quantum Mechanics of Lazy Baker Maps

Abstract We introduce and study the classical and quantum mechanics of certain nonhyperbolic maps on the unit square. These maps are modifications of the usual baker′s map and their behaviour ranges from chaotic motibn on the whole measure to chaos on a set of measure zero. Thus we have called these maps "lazy baker maps." The aim of introducing these maps is to provide the simplest models of systems with a mixed phase space, in which there are both regular and chaotic motions. We find that despite the obviously contrived nature of these maps they provide a good model for the study of the quantum mechanics of such systems. We notice the effect of a classically chaotic fractal set of measure zero on the corresponding quantum maps, which leads to a transition in the spectral statistics. Some periodic orbits belonging to this fractal set are seen to scar several eigenfunctions.
Activation of Three Classes of Nonreceptor Tyrosine Kinases Following Fcγ Receptor Crosslinking in Human Monocytes

Fc gamma receptors on monocytes/macrophages play an important role in both host defense and autoimmune disorders. Fc gamma receptor signaling can lead to such downstream events as phagocytosis and the release of intracellular cytokines and reactive oxygen species. Freshly isolated human monocytes express two major classes of Fc gamma receptor proteins, Fc gamma RI (CD64) and Fc gamma RII (CD32). Crosslinking of Fc gamma RI and Fc gamma RII gives rise to rapid and transient phosphorylation of multiple monocyte intracellular proteins including proteins of 40, 68-72, 75-85, 95, and 115-165 kDa. A 72-kDa protein was earlier identified as the tyrosine kinase Syk. Here we identify one of the proteins in the 115- to 165-kDa cluster as FAK, a protein tyrosine kinase localized to focal adhesions. A 68-kDa phosphoprotein was identified as paxillin, a cytoskeleton associated substrate for tyrosine kinases, and a 95-kDa protein was found to be the proto-oncogene product Vav. The Src family protein tyrosine kinase Fgr (p58) also displayed enhanced tyrosine phosphorylation after Fc gamma RI and Fc gamma RII crosslinking. Although Fc gamma RIIA utilizes tyrosines within its own cytoplasmic domain for signaling while Fc gamma RI utilizes the cytoplasmic tyrosines of its associated gamma subunit, our results indicate sharing of several proteins for signaling in monocytes by these Fc receptors. These molecules include three distinct classes of tyrosine kinases, Syk, FAK, and Fgr, and the functionally diverse proteins Vav and paxillin.
Synthesis of pyrrolizidine alkaloids via rhodium-catalyzed silylformylation and amidocarbonylation

Abstract Rhodium-catalyzed silylformylation and amidocarbonylation are applied to the syntheses of pyrrolizidine alkaloids, (±)-isoretronecanol and (±)-trachelanthamidine, from 5-ethynyl-2-pyrrolidinone.
Polycomb group proteins set the stage for early lineage commitment

Precise control of gene expression patterns is critical for the specification of cellular diversity during metazoan development. Polycomb group (PcG) proteins comprise a class of transcriptional modifiers that have dynamic and essential roles in regulating a number of key processes including lineage commitment. How this is accomplished during mammalian development is incompletely understood. Here, we discuss recent studies in embryonic stem cells (ESCs) that provide critical new insights into how PcG proteins may be targeted to genomic sites as well as the mechanisms by which these regulators influence gene expression and multilineage differentiation in mammals.
Synthesis of porphyrins with four exocyclic rings from 4,5,6,7-tetrahydroindoles

Abstract The 3-alkyl-4,5,6,7-tetrahydroindoles 4a and 4b reacted with lead tetraacetate in acetic acid to give the corresponding 7-acetoxy derivatives; hydrolysis, followed by treatment with potassium ferricyanide in refluxing acetic acid afforded the novel porphyrins 6a and 6b .
Discovering the composite Higgs through the decay of a heavy fermion

A possible composite nature of the Higgs could be revealed at the early stage of the LHC, by analyzing the channels where the Higgs is produced from the decay of a heavy fermion. The Higgs production from a singly-produced heavy bottom, in particular, proves to be a promising channel. For a value = 3 of the Higgs coupling to a heavy bottom, for example, we nd that, considering a 125 GeV Higgs which decays into a pair of b-quarks, a discovery is possible at the 8 TeV LHC with 30 fb 1 if the heavy bottom is lighter than roughly 530 GeV (while an observation is possible for heavy bottom masses up to’ 650 GeV). Such a relatively light heavy bottom is realistic in composite Higgs models of the type considered and, up to now, experimentally allowed. At p s = 14 TeV the LHC sensitivity on the channel increases signicantly.
Third-Degree Price Discrimination in Oligopoly: All-Out Competition and Strategic Commitment

Price discrimination by imperfectly competitive firms may intensify competition, leading to lower prices for all consumers; the tradeoff of consumer groups' welfare that is characteristic of monopolistic discrimination need not arise. This escalation of competition may make firms worse off, and as a result firms may wish to avoid the discriminatory outcome. Under conditions similar to those in which unambiguous price and welfare effects may arise, unilateral commitments not to price discriminate - including the adoption of everyday low pricing or no-haggle policies - may raise firm profits by softening price competition.
An Efficient Bidirectional Approach to the C2-Symmetric Stereoisomers of the Bistetrahydrofuran Core of the Acetogenins

A bidirectional route to nonracemic C2-symmetric bistetrahydrofuran units related to acetogenin natural products was developed starting from the (S,S)-tartrate-derived dialdehyde 3.3. Bis-homologation with the (R)-α-OMOM crotylstannane (R)-4.1 in the presence of InCl3 afforded the anti adduct, diol 4.3. The derived tosylate 4.4, upon treatment with TBAF in THF, underwent sequential TBS cleavage and cyclization to the (R,R,R,R,R,R)-bis-OMOM bistetrahydrofuran 4.7. The epimeric (S,R,R,R,R,S)-bis-OMOM bistetrahydrofuran 4.10 was prepared along similar lines, except that the (R)-α-OMOM crotylstannane (R)-4.1 was first converted to the (R)-γ-isomer (R)-4.2 with BF3·OEt2. Subsequent addition of dialdehyde 3.3 led to the diol adduct 4.5, which after tosylation and treatment with TBAF, yielded the bistetrahydrofuran 4.10. By repeating the aforementioned sequences, but starting with the (S)-α-OMOM-crotylstannane (S)-4.1, the (S,S,R,R,S,S)- and the (R,S,R,R,S,R)-bistetrahydrofurans 5.5 and 5.8 were prepared. A vari...
Bimetallic reactivity. Factors controlling one-site addition two-metal oxidation reactions in bimetallic complexes

A number of bimetallic complexes bearing five- and six-coordinate sites are described for the purpose of achieving one-site addition two-metal oxidation reactions where a substrate adds to the metal at the five-coordinate site and is reduced by both metals. One set of such bimetallic cobalt complexes is found to be either oxidatively unreactive or in some cases when one or the other of the metals is oxidized, the other becomes unreactive to oxidation. This oxidative deactivation is evident even when it is demonstrated that the monometallic constituent parts of the bimetallic complex allow for ready oxidation. It is concluded that the major impediment to bimetallic oxidation is mechanical coupling where the ligand conformation cannot adjust to the structural demands of the higher oxidation state metal. When mechanical coupling is minimized, it is shown that one-site addition two-metal oxidation reactions are observed. With such bimetallic Co2+ complexes NO2+, Br2 and O2 are shown to undergo the expected reactions.
Benzannelated analogs of phenanthro[1,2-b]- and [2,1-b]thiophene: Synthesis and structural characterization by two-dimensional NMR and X-ray techniques

Syntheses of benzo[3,4]phenanthro[1,2-b]thiophene, benzo[3,4]phenanthro[2,1-b]thiophene and their 1-methyl analogs are reported as potential constituents of solvent refined coal liquids and for mutagenicity testing. The attempted synthesis of the 13-methyl analogs which gave the 11-methyl isomers is also described. Total assignments of the 1H- and 13C-nmr spectra based on long range optimized heteronuclear protoncarbon two-dimensional chemical shift correlation are reported. Carbon assignments obtained for benzo[3,4]-phenanthro[1,2-b]thiophene using this approach were confirmed with a 125 MHz 13C–13C INADEQUATE spectrum. X-Ray crystal structures were determined for benzo[3,4]phenanthro[1,2-b]thiophene and 1-methyl-benzo[3,4]phenanthro[2,1-b]thiophene. Both molecules were helically distorted from planarity. Close intramolecular contacts between the bay region H1–H13 and ClMe-H13 of 2.03 and 2.28 A, respectively, were responsible for the distortions. There were no close intermolecular contacts of <3.5A. both molecules refined to an R value of <0.05.
The higher-dimensional Ablowitz–Ladik model: From (non-)integrability and solitary waves to surprising collapse properties and more exotic solutions

Abstract We propose a consideration of the properties of the two-dimensional Ablowitz–Ladik discretization of the ubiquitous nonlinear Schrodinger (NLS) model. We use singularity confinement techniques to suggest that the relevant discretization should not be integrable. More importantly, we identify the prototypical solitary waves of the model and examine their stability, illustrating the remarkable feature that near the continuum limit, this discretization leads to the absence of collapse and complete spectral wave stability, in stark contrast to the standard discretization of the NLS. We also briefly touch upon the three-dimensional case and generalizations of our considerations therein, and also present some more exotic solutions of the model, such as exact line solitons and discrete vortices.
Synthesis of carbazoles and dibenzofurans via cross-coupling of o-iodoanilines and o-iodophenols with silylaryl triflates.

An efficient route to synthesize a variety of carbazoles and dibenzofurans has been developed. It involves the reaction of o-iodoanilines or o-iodophenols with silylaryl triflates in the presence of CsF to afford the N- or O-arylated products, which are subsequently cyclized using a Pd catalyst to carbazoles and dibenzofurans in good to excellent yields. This chemistry tolerates a variety of functional groups.
APPLICATIONS OF SYNCHROTRON X-RAY MICROTOMOGRAPHY TO MESOSCALE MATERIALS

We discuss the application of synchrotron X-ray microtomography (XMT) to granular matter, foams, crumpled membranes, and paper. XMT provides rapid, high-resolution, fully three-dimensional characterization of each of these classes of material. In some cases, subsequent three-dimensional image processing allows the virtual reconstruction of the disordered material as a specified assemblage of idealized basic structural units. This allows measurement of otherwise inaccessible correlation functions and can also be used as the starting point for data-initiated simulations.
X-ray Polarization from Accreting Black Holes: Coronal Emission

We present new calculations of X-ray polarization from accreting black holes (BHs), using a Monte Carlo ray-tracing code in full general relativity. In our model, an optically thick disk in the BH equatorial plane produces thermal seed photons with polarization oriented parallel to the disk surface. These seed photons are then inverse-Compton scattered through a hot (but thermal) corona, producing a hard X-ray power-law spectrum. We consider three different models for the corona geometry: a wedge 'sandwich' with aspect ratio H/R and vertically integrated optical depth tau{sub 0} constant throughout the disk; an inhomogeneous 'clumpy' corona with a finite number of hot clouds distributed randomly above the disk within a wedge geometry; and a spherical corona of uniform density, centered on the BH and surrounded by a truncated thermal disk with inner radius R{sub edge}. In all cases, we find a characteristic transition from horizontal polarization at low energies to vertical polarization above the thermal peak; the vertical direction is defined as the projection of the BH spin axis on the plane of the sky. We show how the details of the spectropolarization signal can be used to distinguish between these models and infer various properties of the corona andmore » BH. Although the bulk of this paper focuses on stellar-mass BHs, we also consider the effects of coronal scattering on the X-ray polarization signal from supermassive BHs in active galactic nuclei.« less
Results from the UCLA/FNPL underdense plasma lens experiment

A gaussian underdense plasma lens with peak density 5 x 10{sup 12} cm{sup -3} and a full width half maximum (FWHM) length of 2.2 cm has been used to focus a relativistic electron beam. This plasma lens is equivalent in strength to a quadrupole magnet with a 150 T/m field gradient. The lens focused a 15 MeV, 16 nC electron beam with initial dimensions {sigma}{sub x,y} {approx} 650 {micro}m and {sigma}{sub z} {approx} 6.5 mm onto an optical transition radiation (OTR) screen {approx}2 cm downstream of the lens. The average transverse area of the plasma focused electron beam was typically demagnified by a factor of 23. The evolution of the beam envelope in the area near the beam waist was measured for both round beams and asymmetric beams with x:y aspect ratios as large as 1:5. The light from the OTR screen in the round beam case was also imaged into a streak camera in order to directly measure the correlation between z and {sigma}{sub r} within the beam.
Ni(OH)2 Nanoplates Grown on Graphene as Advanced Electrochemical Pseudocapacitor Materials

Ni(OH)2 nanocrystals grown on graphene sheets with various degrees of oxidation are investigated as electrochemical pseudocapacitor materials for potential energy storage applications. Single-crystalline Ni(OH)2 hexagonal nanoplates directly grown on lightly oxidized, electrically conducting graphene sheets (GS) exhibit a high specific capacitance of ∼1335 F/g at a charge and discharge current density of 2.8 A/g and ∼953 F/g at 45.7 A/g with excellent cycling ability. The high specific capacitance and remarkable rate capability are promising for applications in supercapacitors with both high energy and power densities. A simple physical mixture of pre-synthesized Ni(OH)2 nanoplates and graphene sheets shows lower specific capacitance, highlighting the importance of direct growth of nanomaterials on graphene to impart intimate interactions and efficient charge transport between the active nanomaterials and the conducting graphene network. Single-crystalline Ni(OH)2 nanoplates directly grown on graphene she...
Biological stimuli and biomolecules in the assembly and manipulation of nanoscale polymeric particles

Living systems are replete with complex, stimuli-responsive nanoscale materials and molecular self-assemblies. There is an ever increasing and intense interest within the chemical sciences to understand, mimic and interface with these biological systems utilizing synthetic and/or semi-synthetic tools. Our aim in this review is to give perspective on this emerging field of research by highlighting examples of polymeric nanoparticles and micelles that are prepared utilizing biopolymers together with synthetic polymers for the purpose of developing nanomaterials capable of interacting and responding to biologically relevant stimuli. It is expected that with the merging of evolved biological molecules with synthetic materials, will come the ability to prepare complex, functional devices. A variety of applications will become accessible including self-healing materials, self-replicating systems, biodiagnostic tools, drug targeting materials and autonomous, adaptive sensors. Most importantly, the success of this type of strategy will impact how biomolecules are stabilized and incorporated into synthetic devices and at the same time, will influence how synthetic materials are utilized within biomedical applications.
The Cauchy problem and integrability of a modified Euler-Poisson equation

We prove that the periodic initial value problem for a modified Euler-Poisson equation is well-posed for initial data in H S (T m ) when s > m/2 + 1. We also study the analytic regularity of this problem and prove a Cauchy-Kowalevski type theorem. After presenting a formal derivation of the equation on the semidirect product space Diff α C ∞ (T) as a Hamiltonian equation, we concentrate on one space dimension (m = 1) and show that the equation is bihamiltonian.
Numerical calculations of the transient loading of blunt obstacles by shocks in air.

This paper presents the results of the application of a numerical method for solving twodimensional fluid dynamics problems to the problem of transient loading of blunt obstacles by shocks in air. The numerical method, a time-dependent pure-Eulerian technique, is applied using a high-speed computer. Two different obstacles are considered under variable incident shock conditions: a rectangular block and a right circular cylinder. Both obstacles are aligned to the flow such that the incident shock is normal to their flat faces. In the case of the block, the calculated results of the transient pressure pulse on the front, top, and back sides are compared with experimental data. The agreement is shown to be quite good. For the right circular cylinder, the loading on only the flat face is investigated. The calculation results are in good agreement with analytical predictions of the overpressure. A consistent error of less than 10% in the calculated time duration of the pulse is estimated on the basis of analytic comparison. In most of the calculations, the equation of state of air is taken to be polytropic. One blunt cylinder calculation, which uses a more realistic equation of state, is included for comparison. The results of this comparison indicate that real air effects can be approximated quite well with the proper choice of 7 in the polytropic equation.
Heliostat Operation at the Central Receiver Test Facility, 1978–1980

The operations and maintenance data and conclusions presented in this are for the 222 heliostats that have been in use at the Central Receiver Test Facility (CRTF) from 1978 through 1980. The CRTF beam produces a total power of 5.5 MWth and a peak intensity of 2250 kW/m/sup 2/ near solar noon. Improvements in the targeting accuracy have been made. The mirror reflectance is maintained near 80 percent by cleaning with rain or snow. The CRTF heliostats logged almost 300,000 operating hrs by the end of 1980.
Unusual behavior of carbocations derived from 2-cumyladamantan-2-ol and its η6-Cr(CO)3 complex

Abstract Acid treatment of the title alcohol leads to both methyl- and aryl-shifted alkene as well as spirocyclopropane products, regardless of whether or not the arene portion of the alcohol is complexed with Cr(CO)3: more polar solvent favors the spirocyclopropane product. The structures and energies of reactants, products, and presumed reaction intermediates are estimated from molecular mechanics calculations.