cssi/SciSciGPT-SciSciNet huggingface dataset:
RATES AND TYPES OF TEACHER PRAISE: A REVIEW AND FUTURE DIRECTIONS

The use of teacher praise in the classroom has been the subject of empirical research since the 1970s, but despite more than four decades of research on the use of teacher praise, large gaps continue to exist in the literature. Clarifying the role and benefit of teacher praise is particularly important because the use of positive, proactive strategies is promoted by large-scale behavior initiatives (e.g., Positive Behavior Interventions and Support). The goal of this review is to summarize the existing research on teacher praise, including rates of praise, types of praise, and the association between praise and student behavior. In addition to summarizing the extant literature, future directions for research are highlighted. This review reveals that there is a need for current, large-scale studies with consistent operational definitions that measure the rate of different types of praise across different grades and instructional activities, while simultaneously measuring student behavioral outcomes.
Geometrization conditions for perfect fluids, scalar fields, and electromagnetic fields

Rainich-type conditions giving a spacetime “geometrization” of matter fields in general relativity are reviewed and extended. Three types of matter are considered: perfect fluids, scalar fields, and electromagnetic fields. Necessary and sufficient conditions on a spacetime metric for it to be part of a perfect fluid solution of the Einstein equations are given. Formulas for constructing the fluid from the metric are obtained. All fluid results hold for any spacetime dimension. Geometric conditions on a metric which are necessary and sufficient for it to define a solution of the Einstein-scalar field equations and formulas for constructing the scalar field from the metric are unified and extended to arbitrary dimensions, to include a cosmological constant, and to include any self-interaction potential. Necessary and sufficient conditions on a four-dimensional spacetime metric for it to be an electrovacuum and formulas for constructing the electromagnetic field from the metric are generalized to include a cosmological constant. Both null and non-null electromagnetic fields are treated. A number of examples and applications of these results are presented.
Value Destruction and Financial Reporting Decisions

The comprehensive survey reported here allowed analysis of how senior U.S. financial executives make decisions related to performance measurement and voluntary disclosure. Chief financial officers were asked what earnings benchmarks they cared about and which factors motivated executives to exercise discretion—even sacrifice economic value—to deliver earnings. These issues are crucially linked to stock market performance. The results show that the destruction of shareholder value through legal means is pervasive, perhaps even a routine way of doing business. Indeed, the amount of value destroyed by companies striving to hit earnings targets exceeds the value lost in recent high-profile fraud cases.
Transverse Cracking of Composite Laminates with Interleaves: A Variational Approach

A two-dimensional shear-lag analysis predicting the effect of interlayers on transverse cracking is developed. The orthotropic nature of the material, as well as crack interactions are incorporated, and a Griffith's type fracture criterion is used to predict the transverse crack failure. The obtained stress solution satisfies the traction-free crack surface boundary conditions. The analysis results are compared to experimental data of a well characterized model material, and parametric studies identifying key parameters in mechanical behavior of interlayered composites are presented.
Self-Regulation in Securities Markets

This paper canvasses the trends in self-regulation and the role of self-regulation in securities markets in different parts of the world. The paper also describes the conditions in which self-regulation might be an effective element of securities markets regulation, particularly in emerging markets. Use of self-regulation and self-regulatory organizations is often recommended in emerging markets as part of a broader strategy aimed at improving the effectiveness of securities regulation and market integrity. According to the International Organization of Securities Commissions, reliance on self-regulation is an optional feature of a regulatory regime. Self-regulatory organizations may support better-regulated and more efficient capital markets, but the value of self-regulation is again being questioned in many countries. Forces such as commercialization of exchanges, development of stronger statutory regulatory authorities, consolidation of financial services industry regulatory bodies, and globalization of capital markets are affecting the scope and effectiveness of self-regulation -- and in particular the traditional role of securities exchanges as self-regulatory organizations.The paper reviews different models of self-regulation, including exchange self-regulatory organizations, member (or independent) self-regulatory organizations, and industry or dealers associations. It draws on examples of self-regulatory organizations from many markets to illustrate the degree of reliance on self-regulation, as well as the range of functions for which self-regulatory organizations are responsible, in markets around the world. Issues that are important to the effective operation of self-regulatory organizations are discussed, such as corporate governance, managing conflicts of interest, and regulatory oversight by government authorities.
Statistics of dark matter substructure – I. Model and universal fitting functions

We present a new, semi-analytical model describing the evolution of dark matter subhaloes. The model uses merger trees constructed using the method of Parkinson et al. (2008) to describe the masses and redshifts of subhaloes at accretion, which are subsequently evolved using a simple model for the orbit-averaged mass loss rates. The model is extremely fast, treats subhaloes of all orders, accounts for scatter in orbital properties and halo concentrations, and uses a simple recipe to convert subhalo mass to maximum circular velocity. The model accurately reproduces the average subhalo mass and velocity functions in numerical simulations. The inferred subhalo mass loss rates imply that an average dark matter subhalo loses in excess of 80 percent of its infall mass during its first radial orbit within the host halo. We demonstrate that the total mass fraction in subhaloes is tightly correlated with the `dynamical age' of the host halo, defined as the number of halo dynamical times that have elapsed since its formation. Using this relation, we present universal fitting functions for the evolved and unevolved subhalo mass and velocity functions that are valid for any host halo mass, at any redshift, and for any {\Lambda}CDM cosmology.
The OLAC metadata set and controlled vocabularies

As language data and associated technologies proliferate and as the language resources community rapidly expands, it has become difficult to locate and reuse existing resources. Are there any lexical resources for such-and-such a language? What tool can work with transcripts in this particular format? What is a good format to use for linguistic data of this type? Questions like these dominate many mailing lists, since web search engines are an unreliable way to find language resources. This paper describes a new digital infrastructure for language resource discovery, based on the Open Archives Initiative, and called OLAC -- the Open Language Archives Community. The OLAC Metadata Set and the associated controlled vocabularies facilitate consistent description and focussed searching. We report progress on the metadata set and controlled vocabularies, describing current issues and soliciting input from the language resources community.
Maximum Flux Transition Paths of Conformational Change

Given two metastable states A and B of a biomolecular system, the problem is to calculate the likely paths of the transition from A to B. Such a calculation is more informative and more manageable if done for a reduced set of collective variables chosen so that paths cluster in collective variable space. The computational task becomes that of computing the “center” of such a cluster. A good way to define the center employs the concept of a committor, whose value at a point in collective variable space is the probability that a trajectory at that point will reach B before A. The committor “foliates” the transition region into a set of isocommittors. The maximum flux transition path is defined as a path that crosses each isocommittor at a point which (locally) has the highest crossing rate of distinct reactive trajectories. This path is based on the same principle as the minimum resistance path of Berkowitz et al (1983), but it has two advantages: (i) the path is invariant with respect to a change of coordinates in collective variable space and (ii) the differential equations that define the path are simpler. It is argued that such a path is nearer to an ideal path than others that have been proposed with the possible exception of the finite-temperature string method path. To make the calculation tractable, three approximations are introduced, yielding a path that is the solution of a nonsingular two-point boundary-value problem. For such a problem, one can construct a simple and robust algorithm. One such algorithm and its performance is discussed.
Formal verification of QVT transformations for code generation

We present a formal calculus for operational QVT. The calculus is implemented in the interactive theorem prover KIV and allows to prove properties of QVT transformations for arbitrary meta models. Additionally, we present a framework for provably correct Java code generation. The framework uses a meta model for a Java abstract syntax tree as the target of QVT transformations. This meta model is mapped to a formal Java semantics in KIV. This makes it possible to formally prove (interactively) with the QVT calculus that a transformation always generates a Java model (i.e. a program) that is type correct and has certain semantical properties. The Java model can be used to generate source code by a model-to-text transformation or byte code directly.
Kathoey "In Trend": Emergent Genderscapes, National Anxieties and the Re-Signification of Male-Bodied Effeminacy in Thailand

Abstract In Thailand, genderscapes, or the terrain of gender and sexuality, continue to evolve quickly, with male-to-female transgenderisms and effeminate gay identities proliferating alongside masculine ones. The previous coding of kathoey in popular discourse as being traditional is shifting to one that identifies “kathoeyness”, or male effeminacy, with modernity. Recent incidents point to a discursive shift based on a purified nostalgia for Thai “tradition”, which excises kathoey presence. In this article, I consider how social evaluation and moral legitimacy underscore the contemporary terrain of gender/sexuality and contradictory attitudes towards kathoeyness. I describe how the increasing visibility of male effeminacy provokes national anxiety, becomes associated with degeneracy, and is used to excise non-normative gender from recent reconstructions of Thainess.
An American Association Of Physicists In Medicine (AAPM) Standard Magnetic Tape Format For Digital Image Exchange

This paper will describe the details of a standard magnetic tape format for digital image exchange; The topics which will be covered include: key-value pairs, required keys, comments, pixel location, and an overview of the software needed to utilize this standard. It will be illustrated by showing: How the standard would be used on a simple image; How additional descriptive information may be added to further annotate this image (the electronic lab notebook); How a tape is created, How images are added to an existing tape; and, How an image is selected and extracted for the tape. A separate paper will describe the philosophy for this standard, motivating the features of the standard, while this paper will focus on the information necessary for implementation of software to support it's use.© (1982) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Symmetric and quasi-symmetric functions associated to polymatroids

To every subspace arrangement X we will associate symmetric functions ?[X] and ?[X]. These symmetric functions encode the Hilbert series and the minimal projective resolution of the product ideal associated to the subspace arrangement. They can be defined for discrete polymatroids as well. The invariant ?[X] specializes to the Tutte polynomial ${\mathcal{T}}[\mathbf{X}]$ . Billera, Jia and Reiner recently introduced a quasi-symmetric function ?[X] (for matroids) which behaves valuatively with respect to matroid base polytope decompositions. We will define a quasi-symmetric function ${\mathcal{G}}[\mathbf{X}]$ for polymatroids which has this property as well. Moreover, ${\mathcal{G}}[\mathbf{X}]$ specializes to ?[X], ?[X], ${\mathcal{T}}[\mathbf{X}]$ and ?[X].
Recent advances in main group fluoride chemistry

Etude des fluorures d'azote, des composes fluoroxy des hypofluorites, des peroxydes fluores, fluorures de soufre
The Local Power Spectrum and Correlation Hierarchy of the Cosmic Mass Field

We analyze the power spectrum of a QSO's Lyα-transmitted flux in the discrete wavelet transform (DWT) representation. Although the mean DWT power spectrum is consistent with its counterpart in Fourier representation, the spatial distribution of the local power varies greatly; i.e., the local DWT power spectra show remarkably spiky structures on small scales. To measure these spiky features, we introduce the quantities roughness of the local power spectrum and correlation between spikes on different scales. We then test the predictions made by the correlation hierarchy model on the roughness and the scale-scale correlations of the local power spectrum. Using the Lyα-transmitted flux of the QSO HS 1700, we find that the underlying cosmic mass field of the transmitted flux at redshift around z 2.2 can be described by the hierarchical clustering model on physical scales from 2.5 h-1 Mpc to a few tens h-1 kpc in an Einstein-de Sitter universe. However, the nonlinear features of the clustering show differences on different scale ranges: (1) On physical scales larger than ~1.3 h-1 Mpc, the field is almost Gaussian. (2) On scales 1.3-0.3 h-1 Mpc, the field is consistent with the correlation hierarchy with a constant value for the coefficient Q4. (3) On scales less than 300 h-1 kpc, the field is no longer Gaussian but essentially intermittent. In this case, the field can still be fitted by the correlation hierarchy, but the coefficient, Q4, should be scale dependent. These three points are strongly supported by the following result: the scale dependencies of Q4 given by two statistically independent measures, i.e., Q by roughness and Q by scale-scale correlation, are the same in the entire scale range considered.
Male-Mediated Developmental Toxicity

The etiology of many of the adverse reproductive outcomes among humans is not well understood. Most epidemiologic and laboratory research focuses on maternal factors. Studies of such adverse developmental outcomes as spontaneous abortion, low birthweight, and birth defects have assessed maternal drug, smoking, alcohol, infectious, and occupational exposures. The potential role of paternal exposures has not been extensively investigated, partly because of the prevailing view that male-mediated developmental effects are unlikely (7). Thus, the acquisition of epidemiologic data and the development of a definitive mechanism for male-mediated effects have been hindered. However, recent laboratory and epidemiologic investigations have reinforced earlier animal data, which suggested that paternal exposures may be important. This review describes potential mechanisms, highlights new data from both laboratory and epidemiologic studies, and points out limitations of previous studies and gaps in knowledge. We review studies that use a variety of developmental endpoints, including gene mutation, chromosomal abnormal­ ities, spontaneous abortion, congenital abnormalities, and cancer. The as yet unclear relationship of these endpoints to effects on sperm production and
Orthonormal integrators based on householder and givens transformations

We consider refined implementations of algorithms based on Householder and Givens transformations to find the Q-factor in the QR-factorization of a matrix solution of linear time dependent differential systems. After discussing the algorithms, we introduce a suite of integrators, QRINT, and provide numerical testing to show the efficiency and accuracy of our techniques.
The Value of the Call Option on a Bond

Publisher Summary Almost all corporate bonds and some government and municipal bonds have call provisions. This call provision gives the issuer the option of buying back his bonds from whoever is holding them at a stated time and price. The call price is typically above par and declines as maturity approaches. Frequently, call is not permitted until several years after the bond has been issued. The call option has value to the issuer for several reasons and this chapter outlines these reasons. The most significant source of value of the option to the issuer is the ability it gives to refinance the issue in the future if interest rates should fall. This chapter explores this aspect of the value of the option and highlights two models. In one of the models, the future price of the bond is assumed to be known and in the other model, the probability distribution of the future price is assumed to be known and to obey certain conditions.
Control of serum potassium during fasting in patients with end-stage renal disease

Control of serum potassium during fasting in patients with end-stage renal disease. In order to evaluate internal potassium balance in patients with end-stage renal disease (ESRD), epinephrine (0.015 µg/kg/min) was infused intravenously into normal control (N = 9) and ESRD subjects (N = 7) after a 26 hour fast. Hyperkalemia developed in ESRD patients after 16 hours of fasting, as compared with control subjects (P = 0.02). The hemodynamic response to epinephrine was similar in the two groups. During epinephrine infusion for one hour, the serum potassium decreased in normal subjects, from 4.3 ± 0.2 mEq/liter to 3.9 ± 0.1 mEq/liter, but did not change in ESRD patients (P = 0.005). Serum CO 2 declined in ESRD, but not in control subjects, while glucose levels were not different in the two groups. Plasma aldosterone was significantly higher in fasting ESRD patients and failed to decrease during epinephrine infusion as compared to controls. Plasma insulin levels remained low in both groups even though serum glucose levels increased. These results demonstrate that hyperkalemia occurs during fasting in ESRD probably as the result of insulinopenia, and suggest that a diminished response to epinephrine may contribute to hyperkalemia.
National Security and the Press: The Government's Ability to Prosecute Journalists for the Possession or Publication of National Security Information

In 2006, then Attorney General Alberto R. Gonzales raised the possibility that journalists could be prosecuted for publishing national security information. In addition, the federal government's prosecution of two former lobbyists for the American Israel Public Affairs Committee (AIPAC) for possessing and disseminating national security information has been called an attempt by the government to prosecute individuals who behave like journalists. This article identifies existing laws under which the press could be criminally prosecuted for the possession and/or publication of national security information and describes how the courts have addressed those laws. The article concludes that while there is support for Constitutional protection for journalists in these cases, the Supreme Court of the United States is unlikely to interpret the First Amendment as protecting journalists from prosecution for possessing and/or publishing national security information. Therefore, the article contends that Congress sho...
Synthesis of four diastereomeric enkephalins incorporating cyclopropyl phenylalanine

Four diastereomeric D-Ala2, Leu5-enkephalins have been synthesized and their CD spectra and rat brain binding affinities determined. Only the peptides containing Z-cyclopropyl phenylalanine residues showed strong binding affinity. No correlation between CD spectra and bioactivity could be made.
Triplet gestation: Maternal and neonatal implications

Triplet pregnancy of over 20 weeks gestation occurred 20 times during 75,506 deliveries at a referral hospital. Commonly occurring maternal complications included premature delivery (75%), antepartum anemia (35%), postpartum hemorrhage (35%), preeclampsia (20%), and premature spontaneous rupture of the membranes (20%). Malpresentation was common. Neonatal complications were also common and included respiratory distress syndrome (45%), presumptive sepsis (36.6%), hyperbilirubinemia (33%), and neonatal death (21.6%). These high complication rates emphasize the importance of early identification and referral center care for these vulnerable pregnancies.
Nonrandom Selection of Hair Follicles in HPRT Heterozygosity

The gene for hypoxanthine phosphoribosyltransferase (HPRT) has been mapped to the X chromosome, and HPRT-deficiency syndromes are inherited in an X-linked recessive manner.1 Two populations of cells can be demonstrated in the female heterozygous carriers of these syndromes. While great strides have been made in the detection of point mutations in cDNA, these methods are not yet sufficiently reliable for routine detection of heterozygotes.2 At present, biochemical methods which detect HPRT+ and HPRT− populations of cells are both technically simpler and more reliable. Cultured fibroblasts, lymphocytes, and hair roots have been used for this purpose.1 Of these three, we have found the hair root method to be the least invasive, fastest, and most reliable.3 In the past 15 years we have detected a total of 94 heterozygous carriers of HPRT-deficiency syndromes by this method.
Disjoint path protection in multi-hop wireless networks with interference constraints

We consider the problem of providing protection against failures in wireless networks by using disjoint paths. Disjoint path routing is commonly used in wired networks for protection, but due to the interference between transmitting nodes in a wireless setting, this approach has not been previously examined for wireless networks. In this paper, we develop a non-disruptive and resource-efficient disjoint path scheme that guarantees protection in wireless networks by utilizing capacity "recapturing" after a failure. Using our scheme, protection can oftentimes be provided for all demands using no additional resources beyond what was required without any protection. We show that the problem of disjoint path protection in wireless networks is not only NP-hard, but in fact remains NP-hard to approximate. We provide an ILP formulation to find an optimal solution, and develop corresponding time-efficient algorithms. Our approach utilizes 87% less protection resources on average than the traditional disjoint path routing scheme. For the case of 2-hop interference, which corresponds to the IEEE 802.11 standard, our protection scheme requires only 8% more resources on average than providing no protection whatsoever.
On the Operator Product Expansion in Noncommutative Quantum Field Theory

Motivated by the mixing of UV and IR effects, we test the OPE formula in non-commutative field theory. First we look at the renormalization of local composite operators, identifying some of their characteristic IR/UV singularities. Then we find that the product of two fields in general cannot be described by a series expansion of single local operator insertions.
Estrogen-induced human luteolysis.

Diethylstilbestrol diphosphate (50 mg daily for 5 days) was given to 3 women for 5 treatment cycles beginning on the third day following the rise in basal body temperature. Daily plasma samples were obtained for radioimmunoassay of progesterone levels. In k treated cycles, a luteolytic effect was apparent by the third day of treatment. This was accompanied by a decrease in the length of the luteal phase by 2-4 days. In the fifth treated cycle, treatment with diethylsti1bestrol beginning 6 or 7 days after ovulation failed to cause luteolysis or interrupt pregnancy.
Ecosystem Modulation of Dissolved Carbon Age in a Temperate Marsh-Dominated Estuary

We measured the concentrations and isotopic values (Δ14C and δ13C) of dissolved inorganic, dissolved organic, and particulate organic carbon (DIC, DOC, and POC, respectively) in the Parker River watershed and estuary in Massachusetts, USA, to determine the age of carbon (C) entering the estuary and how estuarine processing affects the quantity and apparent age of C transported to the Gulf of Maine. The watershed measurements indicated the transport of Δ14C-enriched modern DIC and DOC and variably aged POC from the watershed to the estuary. The transport of organic matter from the watershed was dominated by DOC transport, with POC making up less than 10% of the total. Surveys within the watershed aimed at determining which land-use type dominated the DOC export indicated that wetlands, although they made up only around 20% of the land use, could be responsible for approximately 75% of the DOC export. We therefore conclude that the wetland land uses of the Parker River watershed are exporting mainly Δ14C-enriched modern DOC. DIC isotopes indicate that the source of DIC in the Parker River watershed is dominated by the weathering of noncarbonate parent material by Δ14C-enriched carbon dioxide (CO2) originating from the respiration of young organic matter in soils. Transects in the estuary displayed net additions of all C species. For DOC and DIC, the export of this internally added DOC and DIC was approximately equal to the amount being exported from the watershed, showing the importance of focusing on estuaries when estimating the export of C to the coastal ocean. With respect to DIC, the total input is even larger when the atmospheric exchange of excess pCO2 is calculated. The Δ14C-DOC and Δ14C-DIC transects indicate that the internally added DOC and DIC is Δ14C-enriched modern material. The source of this material is the fringing marshes and estuarine phytoplankton, with the relative importance of these two sources changing over time. Taken together, the bulk C and Δ14C measurements show that the estuary is adding significant quantities of young DOC despite the presence of vast quantities of old marsh peat flanking the entire estuary. Furthermore, the DIC data indicate that Δ14C-enriched modern material is what is fueling the majority of heterotrophic respiration within the system.
2 + 1 Resonance enhanced multiphoton ionization spectroscopy as a tool for stereochemical and conformational analysis of substituted five- and six-membered rings

2 + 1 Resonance enhanced multiphoton ionization (REMPI) spectroscopy is a valuable tool for stereochemical analysis of substituted five- and six-membered cyclic alkanes, ethers, and ketones cooled in supersonic molecular beams. The 3s ← σ and 3s ← n transitions are particularly sensitive to the position of substitution and to the equatorial/axial orientation of alkyl substituents. Transition origin shifts relative to those of the unsubstituted molecule are composed of individual, additive contributions for each unique methyl substituent. Optimized empirical shift parameters have been derived to predict transition origins to within ±85 cm−1 for about 80 methyl substituted cyclohexanes, cyclopentanones, cyclohexanones, and tetrahydropyrans. Structures with multiple conformers can be frozen out in the molecular beam and observed spectroscopically. For the monomethyl substituted six-membered rings, the observed transition intensities have been used to predict ΔG° values for conformational interconversion. Good agreement between the gas and liquid phase ΔG° values has been noted. ΔG° values can be obtained directly from the REMPI spectra for compounds with interconversion barriers lower than 5 kcal mol−1, which is the practical lower limit for low temperature NMR spectroscopy. In addition, multiple rotamer structures for ethyl substituted cyclohexanes have been frozen out in their room temperature Boltzmann distributions. Excellent agreement between the REMPI transition intensities and predicted values obtained from molecular mechanics (MMX) and ab initio methods has been observed. Several empirical correlations between 13C NMR chemical shifts and REMPI transition shifts for the cyclic ketones and cyclohexanes have been observed. These correlations mostly arise for the dependence of both quantities on the ground state steric properties of the molecules.
Spin-dynamics simulations of the triangular antiferromagnetic XY model

Using Monte Carlo and spin-dynamics methods, we have investigated the dynamic behavior of the classical, antiferromagnetic XY model on a triangular lattice with linear sizes $Ll~300.$ The temporal evolutions of spin configurations were obtained by solving numerically the coupled equations of motion for each spin using fourth-order Suzuki-Trotter decompositions of exponential operators. From space- and time-displaced spin-spin correlation functions and their space-time Fourier transforms we obtained the dynamic structure factor $S(\mathbf{q},w)$ for momentum $\mathbf{q}$ and frequency $\ensuremath{\omega}.$ Below ${T}_{\mathrm{KT}}$ (Kosterlitz-Thouless transition), both the in-plane ${(S}^{\mathrm{xx}})$ and out-of-plane ${(S}^{\mathrm{zz}})$ components of $S(\mathbf{q},\ensuremath{\omega})$ exhibit very strong and sharp spin-wave peaks. Well above ${T}_{\mathrm{KT}},$ ${S}^{\mathrm{xx}}$ and ${S}^{\mathrm{zz}}$ apparently display a central peak, and spin-wave signatures are still seen in ${S}^{\mathrm{zz}}.$ In addition, we also observed an almost dispersionless domain-wall peak at high $\ensuremath{\omega}$ below ${T}_{c}$ (Ising transition), where long-range order appears in the staggered chirality. Above ${T}_{c},$ the domain-wall peak disappears for all q. The line shape of these peaks is captured reasonably well by a Lorentzian form. Using a dynamic finite-size scaling theory, we determined the dynamic critical exponent $z=1.002(3).$ We found that our results demonstrate the consistency of the dynamic finite-size scaling theory for the characteristic frequency ${\ensuremath{\omega}}_{m}$ and the dynamic structure factor $S(\mathbf{q},\ensuremath{\omega})$ itself.
Suppression of hole density and hole–hole correlations by Zn impurities in high-Tc superconductors

Abstract By calculating 12th-order high temperature series for the 2D t – J model I investigate the hole density and hole–hole correlations for lattice sites near an isolated Zn impurity. The Zn impurity is modeled as an inert lattice site and the chemical potential is held at the ideal lattice value. The hole density is strongly suppressed at low doping for lattice sites near the Zn impurity. However, this is a very local effect, with the hole density rapidly approaching the bulk value with increasing distance. The hole–hole correlations are also suppressed for lattice sites near the Zn impurity. Both of these effects are strongly doping dependent.
Investor Activism and Financial Market Structure

This article investigates investor activism when there are a number of strategic investors that are capable of intervening in corporate governance. These strategic investors can monitor and/or trade in anonymous financial markets. In equilibrium, a core group of monitoring investors emerges endogenously to curtail managerial opportunism. These core activists both intervene and trade aggressively. Although the smallest investors are passive, there is no monotonic relationship between the size of preexisting shareholdings and activism. In fact, among those investors who choose activism, those with the smallest holdings are the most aggressive.
Synthesis and X-ray structural investigation of cis-hydrido(triphenylsilyl)-1,4-butanediyl-bis-(dicyclohexylphosphine)platinum(II)

Abstract The title compound was prepared by the oxidative addition of triphenylsilane to Pt0[1,4-(Cy2P(CH2)4PCy2)] (where Cy = cyclohexyl) generated in situ. The crystal structure of cis-H(Ph3Si)Pt[Cy2P(CH2)4PCy2] (2) has been determined by single-crystal X-ray diffraction techniques. The square planar geometry about the platinum atom is angularly distorted with a bite angle between the diphosphine ligands (PPtP) of 102.3(1)°. Details of the structural content and selected bond lengths and angles are discussed and presented. The phenyl rings are planar and the cyclohexyl rings are in chair conformations. The enlarged tetrahedral angles at the phosphorus and silicon atoms are probably due to the steric bulk of the ligands. “Ligand profile” calculations (θ/2 vs φ) have been performed to probe the steric interaction about the diphosphine and triphenylsilyl ligands.
DIAGNOSIS OF SICKLE CELL DISEASE BY OPHTHALMOSCOPIC INSPECTION OF THE CONJUNCTIVA

PATIENTS with hemoglobin SS, SC, SD or S thalassemia may exhibit a specific alteration in the conjunctival circulation.1 , 2 The characteristic finding consists of dark-red, comma-shaped or corkscrew-shaped vascular fragments that seem to be isolated from other vessels (Fig. 1); as compared to the normal pattern (Fig. 2), the appearance is striking. The anomalous segments are found mainly in that part of the lower bulbar conjunctiva covered by the lid (Fig. 3). Heretofore, information concerning the nature and significance of this conjunctival sign has been obtained with the slit lamp, an instrument not immediately available to or easily handled by most . . .
Optimal resource allocation for multicast flows in multihop wireless networks

In this paper, we extend recent results on fair and stable resource allocation in wireless networks to include multicast flows, in particular multi-rate multicast. The solution for multi-rate multicast is based on scheduling virtual (shadow) "traffic" that "moves" in reverse direction from destinations to sources. This shadow scheduling algorithm can also be used to control delays in wireless networks.
An Improved Synthesis of Camphorquinone-3-Oxime

Abstract Camphorquinone 3-oxime is prepared in 77% yield in one step from camphor. The synthesis avoids the use of toxic selenium reagents, and provides the syn compound as the major stereoisomer.
Dirac Operator on the Quantum Sphere

Abstract We construct a Dirac operator on the quantum sphere S 2 q which is covariant under the action of SU q (2), compatible with a chirality operator, has the correct commutative limit and also a familiar fuzzy sphere limit. In the fuzzy sphere limit it reduces to Watamuras' Dirac operator. We argue that our Dirac operator may be useful in constructing SU q (2) invariant field theories on S 2 q following the Connes–Lott approach to noncommutative geometry.
Galaxy Luminosity Functions from Deep Spectroscopic Samples of Rich Clusters

Using a new spectroscopic sample and methods accounting for spectroscopic sampling fractions that vary in magnitude and surface brightness, we present R-band galaxy luminosity functions (GLFs) for six nearby galaxy clusters with redshifts of 4000 km s-1 < cz < 20,000 km s-1 and velocity dispersions of 700 km s-1 < σ < 1250 km s-1. In the case of the nearest cluster, A1060, our sample extends to MR = -14 (7 mag below M*), making this the deepest spectroscopic determination of the cluster GLF to date. Our methods also yield composite GLFs for cluster and field galaxies to MR = -17 (M* + 4), including the GLFs of subsamples of star-forming and quiescent galaxies. The composite GLFs are consistent with Schechter functions (M = -21.14, α = -1.21 for the clusters, M = -21.15, α = -1.28 for the field). All six cluster samples are individually consistent with the composite GLF down to their respective absolute magnitude limits, but the GLF of the quiescent population in clusters is not universal. There are also significant variations in the GLF of quiescent galaxies between the field and clusters that can be described as a steepening of the faint-end slope. The overall GLF in clusters is consistent with that of field galaxies, except for the most luminous tip, which is enhanced in clusters versus the field. The star formation properties of giant galaxies are more strongly correlated with the environment than those of fainter galaxies.
Pressure dependence of size effects in superfluid 4He

Abstract We show that the depression of the fourth sound velocity due to size effects over the range 1.4 ⩽ T ⩽ 1.8 K and 0 ⩽ P ⩽ 25 bar can be represented by a function of the displacement thickness δ of Roberts et al. A simple phenomenological model yields values of the healing length which agree with δ within a normalization constant.
High linearity GaN HEMT power amplifier with pre-linearization gate diode

A high linearity MMIC RF power amplifier is reported in the AlGaN/GaN HEMT technology. In order to obtain high linearity, a pre-linearization gate diode is added at the input to compensate for the nonlinear input capacitance C/sub gs/ of the GaN HEMT device. Another single-ended class B power amplifier without the gate diode is also designed for comparison. The circuit with the pre-linearization gate diode demonstrates at least 4dB improvement on 3rd order intermodulation distortion (IMD/sub 3/) performance over the one without the diode over the useful power range in two-tone measurement.
Catalytic, Enantioselective, Vinylogous Aldol Reactions

In 1935, R. C. Fuson formulated the principle of vinylogy to explain how the influence of a functional group may be felt at a distant point in the molecule when this position is connected by conjugated double-bond linkages to the group. In polar reactions, this concept allows the extension of the electrophilic or nucleophilic character of a functional group through the pi system of a carbon-carbon double bond. This vinylogous extension has been applied to the aldol reaction by employing "extended" dienol ethers derived from gamma-enolizable alpha,beta-unsaturated carbonyl compounds. Since 1994, several methods for the catalytic, enantioselective, vinylogous aldol reaction have appeared, with which varying degrees of regio- (site), enantio-, and diastereoselectivity can be attained. In this Review, the current scope and limitations of this transformation, as well as its application in natural product synthesis, are discussed.
Restoration of Fractured Incisal Angles

Fractured incisal angles are restored with use of a procedure that utilizes remaining tooth structure. A shoulder is prepared around and parallel to the fracture; the remaining tooth structure is shaped so that the broadest region is located at the incisal aspect and the narrowest at the shoulder site. The restoration is placed with use of a celluloid tooth form or a stainless steel matrix band.
Infinite horizon equilibrium with incomplete markets

Abstract Competitive equilibrium in a broad class of economies with production, market incompleteness and varying degrees of market participation is studied. Equilibria are characterized as limits of finite horizon truncated equilibria. The key assumption is one of extensibility, meaning that there are short sales restrictions adequate to prevent traders from acquiring debt that they will not be able to honor ex post.
Eigenfeatures coding of videoconferencing sequences

This paper presents a video coding technique that achieves high visual quality at very low bit rates. Each video frame is divided into two regions, consisting of a background area and a visually important feature to be coded at higher bit rates. The feature is tracked from frame to frame and it is coded using a set of features that are extracted from a training set. The set of features, which will be referred to as eigenfeatures, is stored both at the encoder and decoder sites. The technique is based on the eigenfaces method, and achieves high visual quality at high feature compression ratios (around 200 for the salesman sequence and 1000 for the Miss America sequence) with considerably less computational complexity than the eigenfaces method. Using this technique for the feature together with H.261 for the background allows a reduction of up to 70% in the bit rate compared to using H.261 alone.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Protein Conformational Switches: From Nature to Design

Protein conformational switches alter their shape upon receiving an input signal, such as ligand binding, chemical modification, or change in environment. The apparent simplicity of this transformation--which can be carried out by a molecule as small as a thousand atoms or so--belies its critical importance to the life of the cell as well as its capacity for engineering by humans. In the realm of molecular switches, proteins are unique because they are capable of performing a variety of biological functions. Switchable proteins are therefore of high interest to the fields of biology, biotechnology, and medicine. These molecules are beginning to be exploited as the core machinery behind a new generation of biosensors, functionally regulated enzymes, and "smart" biomaterials that react to their surroundings. As inspirations for these designs, researchers continue to analyze existing examples of allosteric proteins. Recent years have also witnessed the development of new methodologies for introducing conformational change into proteins that previously had none. Herein we review examples of both natural and engineered protein switches in the context of four basic modes of conformational change: rigid-body domain movement, limited structural rearrangement, global fold switching, and folding-unfolding. Our purpose is to highlight examples that can potentially serve as platforms for the design of custom switches. Accordingly, we focus on inducible conformational changes that are substantial enough to produce a functional response (e.g., in a second protein to which it is fused), yet are relatively simple, structurally well-characterized, and amenable to protein engineering efforts.
What is Global Studies

In his evocative way, my colleague Jan Nederveen Pieterse has raised a host of interesting questions about the emerging field of global studies, beginning with the puzzler of whether there is a dif...
Predicting objective physical activity from self-report surveys: a model validation study using estimated generalized least-squares regression

Physical activity measurements derived from self-report surveys are prone to measurement errors. Monitoring devices like accelerometers offer more objective measurements of physical activity, but are impractical for use in large-scale surveys. A model capable of predicting objective measurements of physical activity from self-reports would offer a practical alternative to obtaining measurements directly from monitoring devices. Using data from National Health and Nutrition Examination Survey 2003–2006, we developed and validated models for predicting objective physical activity from self-report variables and other demographic characteristics. The prediction intervals produced by the models were large, suggesting that the ability to predict objective physical activity for individuals from self-reports is limited.
Smoothing Riemannian Metrics with Ricci Curvature Bounds

We prove that Riemannian metrics with an absolute Ricci curvature bound and a conjugate radius bound can be smoothed to having a sectional curvature bound. Using this we derive a number of results about structures of manifolds with Ricci curvature bounds.
The electroretinogram: Its components and their origins

Abstract Three major neural components of the mammalian ERG have been demonstrated, including the late RP (receptor potential), b -wave, and d.c. component. These give an adequate explanation of all main features of the cone ERG. Main features of the rod ERG are accounted for by these same three components, plus the c -wave from the pigment epithelium. Different forms of the off-responses in cone and rod ERGs are now readily understood from the rapid decay of the cone late RP, compared with the much slower decay of the rod late RP. The generating cells have been identified for the late RP and c -wave, and the b -wave and d.c. component have been localized to the inner nuclear layer, but the cell types which generate these latter components have not been identified. In addition to the major components, a number of minor components have been found which contribute to the detailed form of the ERG. Such components are still being discovered, and this process may continue. Among these, only the biphasic early RP and the directly-evoked triphasic response of the pigment epithelium cells have been positively identified with particular cell types. In addition to analyzing the ERG into components, and determining the cellular origin of each component, it is especially important to determine the role of each component in retinal functions. This further phase of ERG work is just beginning, since we now have components which are identified with both the receptors and cells of the pigment epithelium.
On the Rotational Evolution of Solar- and Late-Type Stars, Its Magnetic Origins, and the Possibility of Stellar Gyrochronology*

We propose a simple interpretation of the rotation period data for solar- and late-type stars. The open cluster and Mount Wilson star observations suggest that rotating stars lie primarily on two sequences, initially called I and C. Some stars lie in the intervening gap. These sequences, and the fractional numbers of stars on each sequence, evolve systematically with cluster age, enabling us to construct crude rotational isochrones allowing "stellar gyrochronology," a procedure, on improvement, likely to yield ages for individual field stars. The age and color dependences of the sequences allow the identification of the underlying mechanism, which appears to be primarily magnetic. The majority of solar- and late-type stars possess a dominant Sun-like, or interface, magnetic field, which connects the convective envelope to both the radiative interior of the star and the exterior, where winds can drain off angular momentum. These stars spin down Skumanich style. An age-decreasing fraction of young G, K, and M stars, which are rapid rotators, possess only a convective field, which is not only inefficient in depleting angular momentum but also incapable of coupling the surface convection zone to the inner radiative zone, so that only the outer zone is spun down, and on an exponential timescale. These stars do not yet possess large-scale dynamos. The large-scale magnetic field associated with the dynamo, apparently created by the shear between the decoupled radiative and convective zones, (re)couples the convective and radiative zones and drives a star from the convective to the interface sequence through the gap on a timescale that increases as stellar mass decreases. Fully convective stars do not possess such an interface, cannot generate an interface dynamo, and hence can never make such a transition. Helioseismic results for the present-day Sun agree with this scheme, which also explains the rotational bimodality observed by Herbst and collaborators among pre-main-sequence stars and the termination of this bimodality when stars become fully convective. This paradigm also provides a new basis for understanding stellar X-ray and chromospheric activity, light-element abundances, and perhaps other stellar phenomena that depend on rotation.