cssi/SciSciGPT-SciSciNet huggingface dataset:
Epithelium-derived relaxing factor(s) and bronchial reactivity.

Abstract In isolated blood vessels, the mechanical or enzymatic removal of the endothelium augments the contractions evoked by a variety of vasoconstrictor agents, because the endothelial cells release a powerful relaxing substance(s) (endothelium-derived relaxing factor(s)). The focal absence of epithelial cells in airways of patients with asthma is well documented. When the luminal surface of canine bronchi is rubbed gently, the only morphologic change observed is the disappearance of the epithelial cell layer. The removal of the epithelium causes an increased sensitivity of the bronchial smooth muscle to acetylcholine without alteration in the maximal responsiveness to the cholinergic transmitter. The augmentation cannot be attributed to reduced enzymatic breakdown of acetylcholine after removal of the epithelial cells, since it is not affected by inhibitors of acetylcholinesterase. It cannot be attributed to disappearance of a diffusion barrier, since epithelium removal also augments the contractions evoked by electrical stimulation of the cholinergic nerve endings. Removal of the epithelium potentiates the contractions evoked by histamine and 5-hydroxytryptamine in a manner similar to that observed for acetylcholine. The potentiating effect of epithelium removal is more pronounced in larger rather than in smaller bronchi. By contrast, the relaxations evoked by β-adrenergic agonists are less pronounced in bronchi without, rather than in bronchi with, epithelium. The influence of the epithelium on isoproterenol-induced relaxation is more pronounced in smaller rather than in larger bronchi. These observations suggest that the bronchial epithelium releases an inhibitory factor that partially counteracts activation of the airway smooth muscle by bronchoconstrictor substances. Preliminary bioassay studies confirm that the bronchial epithelium can release a potent relaxing substance that inhibits not only bronchial but also vascular smooth muscle. In larger bronchi, the epithelium-derived relaxing factor is released under basal conditions; in smaller bronchi, its release can be activated by catecholamines. The augmentation of the response to bronchoconstrictor agents by removal of the epithelium has been observed, in the author's and other laboratories, in isolated airways from different species.
Void formation and solute segregation in ion-irradiated niobium-base alloys

Abstract The void-volume fraction in unalloyed Nb and Nb-base binary alloys containing either ~ 2.4 a/o Mo, Ti, Zr, Hf, Ni, Fe, V or Ta has been determined from observations of specimens by transmission electron microscopy following 3.0-MeV 58Ni+ ion irradiation at 1225 K to ~ 50 dpa. Also, the thermal- and irradiation-induced segregation of these substitutional-atom solutes to the specimen surface and within the irradiation-damaged layer have been determined by use of the Auger Electron Spectroscopy technique. In addition, the segregation of the intrinsic, interstitial-O impurity (~ 0.06 a/o) in these irradiated or annealed materials has been determined. The void-volume fraction and the segregation of solutes have been shown to be correlated by the solute diffusivity and the relative chemical affinity of the substitutional solutes for O. The correlated diffusion of vacancy defects and O atoms is postulated to explain the experimental results.
Model for radiation contamination by outgassing from space platforms

Abstract : Infrared sensors mounted on space platforms (e.g., Space Shuttle and satellites) may be subject to infrared radiation contamination from molecular gases released from the platform itself. Models for order-of-magnitude estimates of the contamination level caused by this effect are formulated. The mechanisms for vibrational excitation of the ejected species include: (1) thermal excitation at the platform surface, (2) absorption of solar and earthshine radiation, and (3) collisions with ambient atmospheric species. Application of the model to estimate the effects that the outgassing of H20 from the Shuttle environment would have on the CIRRIS 1A earth-limb radiance mission indicates that detection in the 2.7-micro spectral region would by only slightly degraded, but that detection around 6.3 micro may be seriously impaired by the mechanism of absorption and reemission of earthshine radiation by the H20 contamination molecules. Keywords: Radiation contamination, Shuttle environment, Infrared radiation, Spacecraft outgassing.
The Velocity Correlation Function in Cosmic-Ray Diffusion Theory

It is shown that Earl's (1973) eigenvalue sum for the cosmic-ray spatial diffusion coefficient parallel to the mean magnetic field is precisely equivalent to the time integral of the particle-velocity correlation function parallel to the mean field. A derivation due to Kubo (1957) is applied to cosmic-ray pitch-angle scattering, and it is proven that all nine components of the cosmic-ray diffusion tensor can be expressed as integrals over the velocity correlation function. A pitch-angle correlation function is derived, and the effect of long-wavelength turbulence on the velocity correlation function and spatial diffusion coefficients is examined. Application of the velocity-correlation method to a realistic case involving both pitch-angle scattering and appreciable fluctuation in the direction of the local field indicates that long-wavelength turbulence in the local field reduces the parallel diffusion coefficient and places an upper limit on the ratio of the perpendicular to parallel diffusion coefficients.
Automatic quotients of free groups

Abstract Automatic groups admitting prefix-closed automatic structures with uniqueness are characterized as the quotients of free groups by normal subgroups possessing sets of free generators satisfying certain language-theoretic conditions.
The ambivalent dynamics of loyalty in mentorship

This investigation shows that mentorship loyalty is an ambivalent source of tension in the relationship. Data from in-depth interviews show that the mentoring attachment that is rooted in a protective, devoted, affectionate side of loyalty can also compel conformity, suppress dissent, and curb professional growth. The ambivalence stirred up by loyalty issues manifests itself in the nuts and bolts of ordinary interaction. Consideration about what each party `does' for the other, what they are willing to give up or sacrifice for the other, and what each party comes to expect from the other in return evoke conflicts between strategic, emotional, and normative strivings. Ritualized expressions of loyalty — involving material and emotional work — reflect the asymmetry in the mentor—protege authority relationship. Implications for mentoring theory and practice are discussed.
What drives the increased informativeness of earnings announcements over time

Landsman and Maydew (J Acc Res 40:797–808, 2002) document that the information content of earnings announcements has increased over the past three decades, and Francis et al. (Acc Rev, 77:515–546, 2002) conclude that expanded concurrent disclosures in firms’ earnings announcements, especially the inclusion of detailed income statements, explain this increase. We posit and find that the temporal increase in the intensity of the market’s reaction to Street earnings offers a competing explanation for the Landsman and Maydew finding. We also find that expanded concurrent disclosure of GAAP-based information contributes to the temporal increase in the information content of earnings announcements. However, unlike Francis et al., we find that the temporal increase in concurrent balance sheet and cash flow statement information dominates concurrent income statement information once we control for Street earnings.
A general intramolecular Friedel-Crafts approach to functionalized pyrrolo[3,2,1-ij]quinolin-4-ones.

An indium(III)-catalyzed intramolecular Friedel–Crafts annulation for the efficient synthesis of pyrrolo[3,2,1-ij]quinolin-4-ones is described. The products are formed in good to excellent yields (51–97%) with diastereoselectivities up to >99:1 dr.
Staying alert about NAPS.

Nurse-administered propofol sedation (NAPS) is becoming more common. Find out what you need to know about this controversial practice.
Nickel-catalyzed couplings and cyclizations involving allenes, aldehydes, and organozincs

Abstract Cyclizations of allenyl aldehydes and intermolecular couplings of allenes and aldehydes provide a direct procedure for the preparation of homoallylic alcohols. The couplings and cyclizations involve the use of diorganozinc reagents as reducing agents and Ni(COD) 2 as the catalyst.
Lipschitz embeddings of random sequences

We develop a new multi-scale framework flexible enough to solve a number of problems involving embedding random sequences into random sequences. Grimmett et al. (Random Str Algorithm 37(1):85–99, 2010) asked whether there exists an increasing $$M$$ -Lipschitz embedding from one i.i.d. Bernoulli sequence into an independent copy with positive probability. We give a positive answer for large enough $$M$$ . A closely related problem is to show that two independent Poisson processes on $$\mathbb R $$ are roughly isometric (or quasi-isometric). Our approach also applies in this case answering a conjecture of Szegedy and of Peled (Ann Appl Probab 20:462–494, 2010). Our theorem also gives a new proof to Winkler’s compatible sequences problem. Our approach does not explicitly depend on the particular geometry of the problems and we believe it will be applicable to a range of multi-scale and random embedding problems.
Effect of quercetin on human polymorphonuclear leukocyte lysosomal enzyme release and phospholipid metabolism

Quercetin inhibited in a concentration-dependent manner the release of beta-glucuronidase from human polymorphonuclear leukocytes stimulated with zymosan-activated serum. 3H-arachidonic acid-prelabelled polymorphonuclear leukocytes released 3H-arachidonic acid upon stimulation with zymosan-activated serum and this was associated with a decrease of radioactivity in the phospholipid fraction as determined by thin layer chromatography. Quercetin inhibited the release of 3H-arachidonic acid. These observations suggest that the zymosan-activated serum stimulus activates phospholipase A2 and that phospholipase A2 is inhibited by quercetin. Thus, quercetin alters polymorphonuclear leukocyte phospholipid metabolism and responses to stimulation.
Fracture modes in off‐axis fiber composites

Criteria have been developed for identifying, characterizing, and quantifying fracture modes in high-modulus graphite-fiber/resin unidirectional composites subjected to off-axis tensile loading. Procedures are described which use sensitivity analyses and off-axis data to determine the uniaxial strength of fiber composites. It was found that off-axis composites failed by three fracture modes, which produce unique fracture surface characteristics. The stress that dominates each fracture mode and the load angle range of its dominance can be identified. Linear composite mechanics is adequate to describe quantitatively the mechanical behavior of off-axis data are comparable to those measured in uneasily tests.
GENERAL BPS BLACK HOLES IN FIVE DIMENSIONS

An algorithm for constructing general static black hole configuration for the theory of N=2, d= 5 supergravity coupled to an arbitrary number of Abelain vector multiplets is given. The underlying very special geometry structure plays a major role in this construction. From the viewpoint of M-theory compactified on a Calabi–Yau threefold, these black holes are identified with BPS winding states of the membrane around two-cycles of the Calabi–Yau threefold, and thus are of importance in the probing of the phase transitions in the moduli space of M-theory compactified on a Calabi–Yau threefold.
Derivation of a Novel Efficient Supervised Learning Algorithm from Cortical-Subcortical Loops

Although brain circuits presumably carry out powerful perceptual algorithms, few instances of derived biological methods have been found to compete favorably against algorithms that have been engineered for specific applications. We forward a novel analysis of a subset of functions of cortical–subcortical loops, which constitute more than 80% of the human brain, thus likely underlying a broad range of cognitive functions. We describe a family of operations performed by the derived method, including a non-standard method for supervised classification, which may underlie some forms of cortically dependent associative learning. The novel supervised classifier is compared against widely used algorithms for classification, including support vector machines (SVM) and k-nearest neighbor methods, achieving corresponding classification rates – at a fraction of the time and space costs. This represents an instance of a biologically derived algorithm comparing favorably against widely used machine learning methods on well-studied tasks.
A Sheaf of Boehmians

We show that Boehmians defined over open sets of R N consti- tute a sheaf. In particular, it is shown that such Boehmians satisfy the gluing property of sheaves over topological spaces.
(Anti-) stable points and the dynamics of extended systems

Abstract The relation between stable (zero-gradient) points and cellular automata dynamics is explored. Both the number and the nature of stable points influence to some extent the complexity class and stability of rules, and the existence of spatio-temporal structures such as gliders.
Alcohol, ischemic heart disease, and the french paradox

Many studies have shown either an inverse relation between alcohol intake and ischemic heart disease or a U-shaped curve in which the equivalent of two drinks per day of any kind of alcohol is associated with a decreased incidence of coronary disease compared with no drinks, while higher doses result in an increased risk of infarction and stroke. Although the cardioprotective effects of most alcoholic beverages are probably due to an elevation of high-density lipoprotein as well as the ability of alcohol to prevent platelet aggregation and increased fibrinolysis, there is an increased favorable effect of red wine. The unique cardioprotective properties of red wine reside in the action of flavonoids which are absent in white wine (with the exception of champagne) and sparse in beer (with the exception of dark beers). The best researched flavonoids are resveritrol and quercetin, which confer antioxidant properties more potent than alpha-tocopherol. Grape juice has about half the amount of flavonoids by volume as does red wine.
FERRIC CHLORIDE, AN EFFICIENT PROMOTER OF CATIONIC POLYENE CYCLIZATIONS

Abstract The ability of ferric chloride to function as a promoter in biomimetic polyene cyclizations was evaluated using epoxy-polyene 1 as substrate. Reaction of 1 with either FeCl 3 ·6H 2 O or anhydrous FeCl 3 yielded tricyclic alcohols 2a-c in excellent yield, with comparable efficiency to MeAlCl 2 and Ti( i -OPr)Cl 3 . This method can be extended to the cyclization of other polyene substrates, as seen in the conversion of 7 to decalol derivative 8 .
Modeling simple genetic algorithms

The infinite-and finite-population models of the simple genetic algorithm are extended and unified, The result incorporates both transient and asymptotic GA behavior. This leads to an interpretation of genetic search that partially explains population trajectories. In particular, the asymptotic behavior of the large-population simple genetic algorithm is analyzed.
The Age of Choice for Operations of Choice in Infancy and Childhood

Summary While we do not wish to give the impression that necessary surgical procedures should be postponed merely because of the early age of the patient, we firmly believe that there should be a very clear indication for any surgery done during the first two years of a child's life. Though the incidental dangers of surgery at this time are relatively great, with proper and careful technic they can be greatly diminished. But these dangers cannot be disregarded and must be carefully weighed against the actual necessity for the surgical procedure. Some operative procedures now done during the first two years of life have little or no surgical indication. Certainly in infants and young children unnecessary surgery is bad surgery.
Bayesian estimation of panel data fractional response models with endogeneity: an application to standardized test rates

This paper develops new Bayesian estimation procedures for a nonlinear panel data model with a fractional dependent variable which is bounded between zero and one. Specifically, estimation is outlined for a panel data fractional probit model (PFP) and is presented in both a baseline case which assumes strict exogeneity as well as in a more complex simultaneous equation model which allows for potential endogeneity. We also present a new data augmentation technique which allows us to transform the likelihood function of a binary probit model into one which allows for a fractional response. In contrast to Frequentist estimation of the PFP models, Bayesian methods allow for direct evaluation of the joint likelihood of the fractional response, thereby leading to gains in estimation efficiency. Furthermore, transitioning from the strictly exogenous case to the case of endogeneity only requires slight adjustments and this allows for straightforward model specification tests. Combining data from the Florida Department of Education, National Center of Education Statistics, and the U.S. Census Bureau, the model is applied empirically in order to examine the relationship between school spending and student achievement among Florida elementary schools. The study finds that greater spending has a positive and statistically significant effect on student achievement. Though, this effect is roughly 50 % larger in the model which allows for endogenous spending. Specifically, a $1,000 increase in per-pupil spending is associated with an increase in standardized test pass rates ranging from 6.2 to 10.1 %.
Luminescence from self-trapped holes in manganese-doped calcium fluoride single crystals

Abstract Thermally stimulated luminescence (TSL) and electron spin resonance (ESR) measurements on X-irradiated CaF 2 :Mn (0.1 wt.%) single crystals have been conducted in the interval 70 to 300 K. Prominent TSL peaks occur near 150 K (345- and 495-nm emission) and 200 K (predominanlty 495-nm emission) with thermal decay of ESR centers at these same temperatures. Taken collectively the data suggest that 150 K TSL emission is due to mobile holes from V K centers recombining with both trapped electrons and Mn + ions, i.e. , V K + e - → 345-nm emission, and V K + Mn + → (Mn 2+ ) * + hv (495-nm emission). Additionally, H centers are formed by transformation of V K centers. At 200 K, holes from H centers recombine with Mn + to produce excited-state (Mn 2+ ) * which decays by emitting 495-nm radiation.
A response to the commentaries on CoRR

This paper responds to specific comments on, suggestions about, and analysis of ACMs Computing Research Repository (CoRR), agruing that CoRR is both viable and suitably placed amid current online publishing alternatives.
Zirconium-Promoted Epoxide Rearrangement-Alkynylation Sequence

Additions of terminal alkynes to electrophiles are important transformations in organic chemistry. Generally, activated terminal alkynes react with epoxides in an SN2 fashion to form homopropargylic alcohols. We have developed a new synthetic method to form propargylic alcohols from epoxides and terminal alkynes via 1,2-shifts. This method involves cationic zirconium acetylides as both the activator of epoxides and nucleophiles. Due to the mild conditions to pre-activate alkynes with silver nitrate, this synthetic method is useful for both electron-rich and electron-deficient alkynes with other acid- and base-sensitive functional groups.
Carboxylic Acid (Bio)Isosteres in Drug Design

The carboxylic acid functional group can be an important constituent of a pharmacophore, however, the presence of this moiety can also be responsible for significant drawbacks, including metabolic instability, toxicity, as well as limited passive diffusion across biological membranes. To avoid some of these shortcomings while retaining the desired attributes of the carboxylic acid moiety, medicinal chemists often investigate the use of carboxylic acid (bio)isosteres. The same type of strategy can also be effective for a variety other purposes, for example, to increase the selectivity of a biologically active compound or to create new intellectual property. Several carboxylic acid isosteres have been reported, however, the outcome of any isosteric replacement cannot be readily predicted as this strategy is generally found to be dependent upon the particular context (i.e., the characteristic properties of the drug and the drug–target). As a result, screening of a panel of isosteres is typically required. In this context, the discovery and development of novel carboxylic acid surrogates that could complement the existing palette of isosteres remains an important area of research. The goal of this Minireview is to provide an overview of the most commonly employed carboxylic acid (bio)isosteres and to present representative examples demonstrating the use and utility of each isostere in drug design.
A study of large field configurations in MC simulations

Abstract We discuss a new approach of scalar field theory where the small field contributions are treated perturbatively and the large field configurations (which are responsible for the asymptotic behavior of the perturbative series) are neglected. In two Borel summable λϕ4 problems improved perturbative series can be obtained by this procedure. The modified series converge towards' values exponentially close to the exact ones. For λ larger than some critical value, the method outperforms Pade´'s approximants and Borel summations. The method can also be used for series which are not Borel summable such as the double-well potential series and provide a perturbative approach of the instanton contribution. Semi-classical methods can be used to calculate the modified Feynman rules, estimate the error and optimize the field cutoff. We discuss Monte Carlo simulations in one and two dimensions which support the hypothesis of dilution of large field configurations used in these semi-classical calculations. We show that Monte Carlo methods can be used to calculate the modified perturbative series.
On the ratio of revenue to welfare in single-parameter mechanism design

What fraction of the potential social surplus in an environment can be extracted by a revenue-maximizing monopolist? We investigate this problem in Bayesian single-parameter environments with independent private values. The precise answer to the question obviously depends on the particulars of the environment: the feasibility constraint and the distributions from which the bidders' private values are sampled. Rather than solving the problem in particular special cases, our work aims to provide universal lower bounds on the revenue-to-welfare ratio that hold under the most general hypotheses that allow for non-trivial such bounds.Our results can be summarized as follows. For general feasibility constraints, the revenue-to-welfare ratio is at least a constant times the inverse-square-root of the number of agents, and this is tight up to constant factors. For downward-closed feasibility constraints, the revenue-to-welfare ratio is bounded below by a constant. Both results require the bidders' distributions to satisfy hypotheses somewhat stronger than regularity; we show that the latter result cannot avoid this requirement.
The social value of risk-free government debt

Can eliminating the stock of government bonds reduce welfare? When the government must raise revenue to pay interest on its bonds, the social value of government debt hinges on whether the benefits from greater portfolio diversification outweigh the costs of the revenue-raising efforts. A positive stock of debt is optimal only if interest payments are financed by an inflation tax, agents are not too risk averse, there is a government budget deficit, and the economy is on the bad side of the Laffer curve. Welfare is higher on the good side of the Laffer curve without bonds.
An executive system for on-line programming on a small-scale system

The role of Executive Control Programs is increasing with the number and size of the applications of computers to data processing problems. As problems become more complex and as the computer's external equipment becomes more numerous, Executive Control Programs serve as monitors in increasing the efficiency of the computer as well as its capability of shared utilization of hardware and software. They are, therefore, an enlightened compromise of hardware and software.
Multicomponent stacking-velocity tomography for transversely isotropic media

Accurate estimation of the velocity field is the most difficult step in imaging of seismic data for anisotropic media. Here, the velocity‐analysis problem is examined for the most common anisotropic model of sedimentary formations—transverse isotropy (TI) with arbitrary orientation of the symmetry axis. We show that supplementing wide‐azimuth reflected PP data with mode‐converted (PS) waves yields more stable estimates of the anisotropic coefficients and, in many cases, helps to constrain the model in depth.An important processing step preceding the inversion is computation of the traveltimes of the pure SS‐waves from those of the PP‐, and PS‐waves based on a technique recently developed by Grechka and Tsvankin. This procedure allows us to replace PS‐wave moveout, which is generally asymmetric with respect to zero offset, with the symmetric (hyperbolic on short spreads) moveout of the pure SS reflections. Then, generalizing the algorithm previously suggested for PP data, we develop a joint tomographic inv...
Segmentation of multivariate mixed data via lossy coding and compression

In this paper, based on ideas from lossy data coding and compression, we present a simple but surprisingly effective technique for segmenting multivariate mixed data that are drawn from a mixture of Gaussian distributions or linear subspaces. The goal is to find the optimal segmentation that minimizes the overall coding length of the segmented data, subject to a given distortion. We show that deterministic segmentation minimizes an upper bound on the (asymptotically) optimal solution. The proposed algorithm does not require any prior knowledge of the number or dimension of the groups, nor does it involve any parameter estimation. Simulation results reveal intriguing phase-transition behaviors of the number of segments when changing the level of distortion or the amount of outliers. Finally, we demonstrate how this technique can be readily applied to segment real imagery and bioinformatic data.
Quantifying the unimportance of prior probabilities in a computer vision problem

Abstract We present an empirical investigation of the importance of accurate assessment of prior probabilities in a typical visual classification problem, handwritten ZIP Code recognition. We found that little accuracy was gained by accurate assessment of the prior distribution over the individual digits.
ELECTRONS AND PROTONS IN LONG-LIVED STREAMS OF ENERGETIC SOLAR PARTICLES

In 1966 and 1967 many long-lived streams of low-energy solar electrons and protons were observed near Earth. These streams were sometimes associated with bright flares which occurred many hours earlier and sometimes no individual flare could be found. In the latter case the particles are evidently to be associated in a general way with solar active centers as Fan et al. (1968) have done. The long-lived solar events discussed here include energetic storm particles, delayed events and fluxes associated with solar active regions. It is suggested here that these are all probably the same basic phenomena viewed in somewhat different ways depending on the age of the region and its location on the solar disc. These events are usually associated with a depression in the sea-level neutron intensity and one or more sudden commencements or sudden impulses. Both electrons and protons are present in these events but in several cases electrons were not detected. The most unusual feature is that when both particle species are present, the electron flux is centered several hours before the proton flux.
Critical Values for Cointegration Tests in Heterogeneous Panels with Multiple Regressors

I. INTRODUCTION In this paper we describe a method for testing the null of no cointegration in dynamic panels with multiple regressors and compute approximate critical values for these tests. Methods for non-stationary panels, including panel unit root and panel cointegration tests, have been gaining increased acceptance in recent empirical research. To date, however, tests for the null of no cointegration in heterogeneous panels based on Pedroni (1995, 1997a) have been limited to simple bivariate examples, in large part due to the lack of critical values available for more complex multivariate regressions. The purpose of this paper is to fill this gap by describing a method to implement tests for the null of no cointegration for the case with multiple regressors and to provide appropriate critical values for these cases. The tests allow for considerable heterogeneity among individual members of the panel, including heterogeneity in both the long-run cointegrating vectors as well as heterogeneity in the dynamics associated with short-run deviations from these cointegrating vectors.
THE EFFECTS OF EMPLOYMENT WHILE PREGNANT ON HEALTH AT BIRTH

Today, many pregnant women take a brief period of time off from work to give birth. In this paper, I identify the effects of pregnancy employment on health at birth. My initial results show that pregnancy employment has beneficial effects. However, these effects often become statistically insignificant when I control for earnings from pregnancy employment, when I exclusively examine women employed prior to the pregnancy, and when I examine siblings in fixed effects models. I conclude that beneficial effects of pregnancy employment are partially due to increased family income via earnings during the pregnancy and partially due to unobserved heterogeneity. There is no evidence that increased female labor force participation adversely affects health at birth.
A high-order fast method for computing convolution integral with smooth kernel

In this paper we report on a high-order fast method to numerically calculate convolution integral with smooth non-periodic kernel. This method is based on the Newton-Cotes quadrature rule for the integral approximation and an FFT method for discrete summation. The method can have an arbitrarily high-order accuracy in principle depending on the number of points used in the integral approximation and a computational cost of O(Nlog(N)), where N is the number of grid points. For a three-point Simpson rule approximation, the method has an accuracy of O(h{sup 4}), where h is the size of the computational grid. Applications of the Simpson rule based algorithm to the calculation of a one-dimensional continuous Gauss transform and to the calculation of a two-dimensional electric field from a charged beam are also presented.
Preparation of Some Derivatives of N‐tert‐Butyldecahydro‐3‐isoquinoline Carboxamide

Abstract N‐tert‐Butyldecahydro‐3‐isoquinoline carboxamide (1) is a key structural fragment present in a variety of medicinally important HIV protease inhibitors. Derivatives of this carboxamide were prepared by alkylation with either 2‐iodoethanol, allyl bromide, or bromoacetaldehyde dimethylacetal. The corresponding aldehyde of the dimethylacetal derivative was prepared by reaction with BBr3 in CH2Cl2.
A Two-Dimensional Position Sensitive Si(Li) Detector

Circular, large-area two-dimensional Si(Li) position sensitive detectors have been fabricated. The detectors employ a thin lithium-diffused n+ resistive layer for one contact and a boron-implanted p+ resistive layer for the second contact. A position resolution of the order of 100 ?m is indicated.
Light absorption by an atom moving inside a spherical box

Abstract The radiative transition for an atom moving inside a spherical box is considered in the terms of electronic-field states. By using the hopping model, an analytical expression is obtained for the transition probability. This expression is compared with results obtained by numerical integration of the time-dependent Schrodinger equation.
The maximum likelihood approach to voting on social networks

One view of voting is that voters have inherently different preferences - de gustibus non est disputandum - and that voting is merely a method for reaching a reasonable compromise solution. An alternative view is that some of the alternatives really are better in an objective sense, and by voting over the alternatives we hope to be more likely to reach the correct outcome. In this latter view, we can see the votes as noisy estimates of the truth. Specifying a probabilistic noise model gives us a natural “optimal” voting rule for determining the outcome based on the votes, namely, the function that takes the votes as input and produces the outcome that maximizes the likelihood of these votes as output. We will first review some of the work on the maximum likelihood approach to voting. Most of this work supposes that, conditional on the correct outcome, votes are independent. In reality, however, voters are clearly influenced by the opinions of those close to them. How should we model the effects of the social network, and what does this imply for the maximum likelihood approach? We will first review an earlier result [1] that states that, under certain assumptions, the social network structure should not affect the voting rule. We then consider a new model under which this is not true, and prove that computing the probability of the votes given the correct outcome is #P-hard under this model. On the other hand, if the goal is to simultaneously also give a point estimate of the hidden variables in the model, then the optimization problem can be solved in polynomial time.
NLO QCD corrections to hadronic Higgs production with heavy quarks

The production of a Higgs boson in association with a pair of tt or bb quarks plays a very important role at both the Tevatron and the Large Hadron Collider. The theoretical prediction of the corresponding cross sections has been improved by including the complete next-to-leading order QCD corrections. After a brief description of the most relevant technical aspects of the calculation, we review the results obtained for both the Tevatron and the Large Hadron Collider.
Anatomy and Pathology of the Eye: Role of MR Imaging and CT

Since the development of CT and MR imaging, significant progress in ophthalmic imaging has been made. As the technology advanced and MR imaging units improved their ability in terms of spatial resolution, the role of MR imaging in ophthalmic imaging has increased accordingly. This article considers the role of MR and CT imaging in the diagnosis of selected pathologies of the eye.
Ferromagnetic Iron Boride (Fe3B) Nanowires

Single-crystal iron boride (Fe3B) nanowires were synthesized on Pt and Pd (Pt/Pd) coated sapphire substrates by a chemical vapor deposition method at 800 °C using boron triiodide (BI3) and iron iodide (FeI2) as precursors. Morphology of the Fe3B nanowires can be controlled by manipulating the Pt/Pd film thickness and the growth time. Transmission electron microscopy and selected area electron diffraction were used to analyze the crystal structures of these novel materials. Electron energy-loss spectroscopy and X-ray energy-dispersive spectroscopy studies on these nanowires confirm that they are composed of boron and iron. Scanning electron microscopy was employed to observe the morphology of these nanomaterials. The typical size of the iron boride nanowires is about 5−50 nm in width and 2−30 μm in length. The vapor−liquid−solid (VLS) growth process is shown to be the growth mechanism of the Fe3B nanowires. Room temperature magnetic force microscopy investigations on the iron boride nanowires suggest that ...
Poisson?Boltzmann theory of charged colloids: limits of the cell model for salty suspensions

Thermodynamic properties of charge-stabilized colloidal suspensions and polyelectrolyte solutions are commonly modelled by implementing the mean-field Poisson-Boltzmann (PB) theory within a cell model. This approach models a bulk system by a single macroion, together with counterions and salt ions, confined to a symmetrically shaped, electroneutral cell. While easing numerical solution of the nonlinear PB equation, the cell model neglects microion-induced interactions and correlations between macroions, precluding modelling of macroion ordering phenomena. An alternative approach, which avoids the artificial constraints of cell geometry, exploits the mapping of a macroion-microion mixture onto a one-component model of pseudo-macroions governed by effective interparticle interactions. In practice, effective-interaction models are usually based on linear-screening approximations, which can accurately describe strong nonlinear screening only by incorporating an effective (renormalized) macroion charge. Combining charge renormalization and linearized PB theories, in both the cell model and an effective-interaction (cell-free) model, we compute osmotic pressures of highly charged colloids and monovalent microions, in Donnan equilibrium with a salt reservoir, over a range of concentrations. By comparing predictions with primitive model simulation data for salt-free suspensions, and with predictions from nonlinear PB theory for salty suspensions, we chart the limits of both the cell model and linear-screening approximations in modelling bulk thermodynamic properties. Up to moderately strong electrostatic couplings, the cell model proves accurate for predicting osmotic pressures of deionized (counterion-dominated) suspensions. With increasing salt concentration, however, the relative contribution of macroion interactions to the osmotic pressure grows, leading predictions from the cell and effective-interaction models to deviate. No evidence is found for a liquid-vapour phase instability driven by monovalent microions. These results may guide applications of PB theory to colloidal suspensions and other soft materials.
The hydroxylation and amidation of equilenin acetate catalyzed by chloro[5,10,15,20-tetrakis(pentafluorophenyl)porphyrinato]manganese(III)

The aromatic steroid equilenin acetate undergoes regioselective and stereoselective hydroxylation and amidation catalyzed by a manganese porphyrin using iodosobenzene (PhIO) and N-tosyliminophenyliodinane (PhINTs) as the oxygen and nitrogen donor, respectively.
The distribution of points on curves over finite fields in some small rectangles

Let $$p$$ be a prime. We study the distribution of points on a class of curves $$C$$ over $$\mathbb{F }_p$$ inside very small rectangles $$\mathcal{B }$$ for which the Weil bound fails to give nontrivial information. In particular, we show that the distribution of points on $$C$$ over long rectangles is Gaussian.
Effects of Dichotically Presented Simultaneous Synchronous and Delayed Auditory Feedback on Key Tapping Performance

A selective replication of Tsunoda's (1966) application of the DAF key tapping paradigm to the study of functional auditory asymmetry was conducted. Present findings do not offer confirmation of Tsunoda's assertion that most subjects will exhibit performance disruption at a lower intensity level when a vowel is delayed at the right ear and when a pure tone is delayed at the left ear. In the present study, it was found that no difference existed between the pure tone and the vowel delayed to the left ear conditions in terms of performance deterioration. The significant difference in performance disruption between the vowel delayed to the right ear condition and the pure tone delayed to the right ear condition was interpreted to be suggestive of functional auditory asymmetry.
Single-Flask Synthesis of N-Acylated Indoles by Catalytic Dehydrogenative Coupling with Primary Alcohols

Indoles and alcohols can be coupled in a dehydrogenative process catalyzed by tetrapropylammonium perruthenate. This efficient approach to indolylamides proceeds in a single flask under mild conditions. By employing substituted indoles and alkyl, branched, or benzylic alcohols, a variety of indolylamides can be formed. Aryl indolylamides can be functionalized through an additional dehydrogenative coupling to furnish elaborated polycyclic heterocycles similar to biologically active structures previously reported.
Total synthesis of the Securinega alkaloids

Covering: 1966 to the beginning of 2009The Securinega alkaloids are a small family of plant metabolites with fascinating bridged tetracyclic structures and significant biological activity. These compounds have drawn increasing interest from synthetic chemists, resulting in a number of innovative total syntheses. This review describes the various synthetic approaches to members of the Securinega family of alkaloids published over the last four decades.
Domestic violence exposure in Colombian adolescents: Pathways to violent and prosocial behavior*‡

Associations between domestic violence exposure and violent and prosocial behavior were tested in a sample of Colombian adolescents, with attention to impulsivity and substance use problems as mediators of these associations. A representative sample of 1,152 school youths and a convenience group of 148 juvenile offenders aged 11-19 years participated. Results using structural equation modeling showed indirect effects of impulsivity and substance use problems between family violence (i.e., exposure to interparental violence) and violent behavior. Maltreatment (i.e., harsh parenting) was directly associated with violent behavior, though impulsivity and substance use problems also mediated this relation. Maltreatment directly and inversely contributed to prosocial behavior but there was no evidence of mediation. Results are discussed in terms of cognitive and behavioral factors that explain violent and prosocial behavior among Colombian youths. Limitations and implications for prevention are described. Language: en
The Electronic Nature and Reactivity of the Larger Acenes

The astounding electronic performance of acenes such as tetracene and pentacene (and their heteroaromatic counterparts) stands to revolutionize the field of organic electronics, promising novel consumer electronics for power generation and information display in lightweight, flexible form factors. These results have rekindled interest in acenes larger than pentacene, to determine how electronic properties are further altered by extending conjugation. This research has had to encompass many fundamental studies, as even the simple nature of aromaticity in larger acenes is still a controversial topic. Further, the reactivity of acenes toward oligomerization or oxidation becomes significant in larger acenes, while the diminishing solubility complicates isolation and characterization. This article surveys recent works describing the nature of aromaticity and reactivity in larger acenes, methods used to prepare parent acenes larger than pentacene, and functionalization approaches to soluble, reasonably stable large acenes.
Effects of CMC addition on bacterial cellulose production in a biofilm reactor and its paper sheets analysis.

Bacterial cellulose (BC) can be grown into any desired shape such as pellicles, pellets, and spherelike balls, depending on the cultivation method, additives, and cell population. In this study, Ac...
Derivative corrections to the D-brane Born-Infeld action: non-geodesic embeddings and the Seiberg-Witten map

We dimensionally reduce the four-derivative corrections to the parity-conserving part of the D9-brane effective action involving all orders of the gauge field, to obtain corrections to the actions for the lower-dimensional Dp-branes. These corrections involve the second fundamental form and correspond to a non-geodesic embedding of the Dp-brane into (flat) ten-dimensional space. In addition, we study the transformation of the corrections under the Seiberg-Witten map relating the ordinary and non-commutative theories. A speculative discussion about higher-order terms in the derivative expansion is also included.
Negative contributions to S in an effective field theory

We show that an effective field theory that includes non-standard couplings between the electroweak gauge bosons and the top and bottom quarks may yield negative contributions to both the S and T oblique radiative electroweak parameters. We find that that such an effective field theory provides a better fit to data than the standard model (the χ 2 per degree of freedom is half as large). We examine in some detail an illustrative model where the exchange of heavy scalars produces the correct type of non-standard couplings.
Milankovitch and global ice volume simulation

The wastage and accumulation rates of the global ice sheets are taken to be climatic parameters, responding to astronomical forcing, and the global ice volume to be the integral of the difference of these two rates. The particular form of the climatic response function is that it is proportional to the seasonality of irradiance totals. Taking the Fourier series of the ten major periodicities longer than ten millenia in the Berger formulation of the Milankovitch concept as the forcing function, analytical integration yields a time series that correlates about 0.51 with the ice volume reconstruction from oxygen isotopes for the past half million years, and matches the maxima and minima optimally. The integration process resolves part of the previous difficulty of ice volume spectra with too much power in the lowest frequencies.
Regio- and Stereospecific Formation of Protected Allylic Alcohols via Zirconium-Mediated SN2‘ Substitution of Allylic Chlorides

A new, highly regio- and stereospecific SN2' substitution reaction between a zirconium oxo complex and allylic chloride has been achieved. The resulting allylic alcohol or TBS-protected allylic ether products were isolated in good to excellent yields with a wide range of E-allylic chlorides. A mechanism for the SN2' allylic substitution consistent with kinetic, stereochemical and secondary isotope effect studies was proposed.
Inca and colonial settlement, coca cultivation and endemic disease in the tropical forest.

Abstract A configuration unfolds from early colonial chronicles, the archaeological record and epidemiological evidence that infectious disease was a critical factor in constraining durable pre-Hispanic settlement in the Amazon forest. The Incas' main interest in the wet tropical valleys beyond the mountain front, particularly those northeast of Cuzco the capital, was to grow coca. Quest for the sacred leaf justified intrusions into a hyperendemic zone of mucocutaneous leishmaniasis, a complex protoxoal disease carried by sand flies that results in dermal lesions and grotesque necrosis of the face. In an effort to avoid this disfiguring disease, the Incas carried on trade relations with forest tribes, subjugated some of these tribes to clear the forest for them, and shifted people from analogous climates elsewhere. The most important mechanism was to control the length of the work period of coca labourers from the highlands. Traditional vertical migration of Andean natives and siting of pre-Conquest dwelling sites largely above the zone of leishmaniasis contraction suggest an ancient geographical pattern of disease avoidance. After the Conquest, disease mortality was very high, as Spaniards expanded coca cultivation but disregarded many of the indigenous safeguards. Adjustments to an insalubrious yet compelling environment are more persuasive than agricultural limitations in understanding the deep-seated past aversion of highland Indians to sustained occupance of the selva.
A timeout distribution for reduced contention in a decentralized random access channel

Abstract We derive a timeout distribution that is optimal in some lightly loaded random access channels. This distribution, which has a triangular density, can reduce the probability of successive collisions by as much as 11.1% with respect to the standard exponential backoff.