cssi/SciSciGPT-SciSciNet huggingface dataset:
Generalized nonconvex optimization for medical image segmentation

Design of a generalized technique for medical image segmentation is a challenging task. Currently a number of approaches are being investigated for 2-D and 3-D medical image segmentation for diagnostic and research applications. The methodology used in this work is aimed at obtaining a generalized solution of non-convex optimization problems by including a structural constraint of mass or density and the concept of additivity properties of entropy to a recently developed statistical approach to clustering and classification. The original computationally intensive procedure is made more efficient both in processing time and accuracy by employing a new similarity parameter for generating the initial clusters that are updated by minimizing an energy function relating the image entropy and expected distortion. The application of the computationally intensive yet generalized solution to nonconvex optimization to a limited set of medical images has resulted in excellent segmentation when compared to other clustering based segmentation approaches. The addition of the parametric approach to determine the initial number of clusters allows significant reduction in processing time and better design of automated segmentation procedure. This research work generalizes a deterministic annealing i.e. a specific statistical approach to solve nonconvex optimization problems by developing a more efficient technique applicable to nonconvex optimization problems (getting trapped in local minima). However, the DA approach is extremely computationally intensive for applications such as image segmentation. The new integrated approach developed in this work allows this optimization technique to be used for medical image segmentation.
Samarium(II) Iodide Mediated Radical/Polar Crossover Reactions of Cyclobutenes. An Efficient Approach to the BCD Ring System of the Penitrems

Radical/polar crossover reactions of derivatives of 1-(2-cyclobutenyl)-2-(2-iodoaryl)ethanones with acetone promoted by samarium diiodide and HMPA provide 1-(1-hydroxy-1-methylethyl)-2,2a,4,8b-tetrahydro-1H-cyclobuta[a]naphthalen-3-one derivatives in about 50% isolated yield. This reaction shows promise for construction of the BCD ring fragment of the penitrems.
Reverse wave suppression in unstable ring resonator

The effectiveness of a reverse wave suppressor (RWS) mirror in an unstable ring resonator has been investigated theoretically and experimentally for the case of an inhomogeneously broadened gain medium. The theory indicates that the RWS mirror is effective when (δ/Δνh)2 ≪ 1, where Δνh is the characteristic homogeneous linewidth of the gain medium and δ = Δu(ν0/c) is a measure of the separation between competing forward and reverse waves. Unstable linear ring resonator experiments were conducted using a continuous wave HF laser. Successful suppression of the reverse wave was achieved. In these tests the ratio of forward to reverse power had an average value of 41. An unstable annular ring resonator was investigated using a pulsed CO2 laser. Reverse wave suppression was achieved when the resonator and RWS mirror were in good alignment. Suppression effectiveness and beam quality were degraded when the RWS mirror was tilted.
Preventing the Next Fukushima

While this year's disaster at Japan's Fukushima Dai'ichi plant, the worst since Chernobyl in 1986, was caused by the one-two punch of a huge earthquake followed by an immense tsunami—a disaster unlikely to occur in many locations—it revealed technical and institutional weaknesses that must be fixed around the world. If nuclear power is to grow on the scale required to be a significant part of the solution to global climate disruption or scarcity of fossil fuels, major steps are needed to rebuild confidence that nuclear facilities will be safe from accidents and secure against attacks ( 1 ).
Mira B Rejuvenated

Recent ultraviolet spectra from the Hubble Space Telescope (HST) and Far Ultraviolet Spectroscopic Explorer (FUSE) satellites demonstrate that UV line and continuum fluxes observed from Mira B are increasing back toward the levels that the International Ultraviolet Explorer (IUE) observed in 1979-1980 and 1990-1995, after having been found in a very low state by HST and FUSE in 1999-2001. The UV emission is associated with accretion of material onto Mira B from Mira A's massive wind, so the variability is presumably due to variations in accretion rate. From wind absorption features, we estimate a Mira B mass-loss rate of 2.5 × 10-12 M☉ yr-1, indicating that Mira B's wind has increased in strength along with the accretion rate. The UV variability may be associated with a previously reported 14 yr periodicity in Mira B's optical emission.
Exploring Linked Data with contextual tag clouds

In this paper we present the contextual tag cloud system: a novel application that helps users explore a large scale RDF dataset. Unlike folksonomy tags used in most traditional tag clouds, the tags in our system are ontological terms (classes and properties), and a user can construct a context with a set of tags that defines a subset of instances. Then in the contextual tag cloud, the font size of each tag depends on the number of instances that are associated with that tag and all tags in the context. Each contextual tag cloud serves as a summary of the distribution of relevant data, and by changing the context, the user can quickly gain an understanding of patterns in the data. Furthermore, the user can choose to include RDFS taxonomic and/or domain/range entailment in the calculations of tag sizes, thereby understanding the impact of semantics on the data. In this paper, we describe how the system can be used as a query building assistant, a data explorer for casual users, or a diagnosis tool for data providers. To resolve the key challenge of how to scale to Linked Data, we combine a scalable preprocessing approach with a specially-constructed inverted index, use three approaches to prune unnecessary counts for faster online computations, and design a paging and streaming interface. Together, these techniques enable a responsive system that in particular holds a dataset with more than 1.4 billion triples and over 380,000 tags. Via experimentation, we show how much our design choices benefit the responsiveness of our system.
Density and Temperature Structure of TMC-1C from 450 and 850 Micron Maps

We have mapped the central 10' × 10' of the dense core TMC-1C at 450 and 850 μm using SCUBA on the James Clerk Maxwell Telescope. The unusually high quality of the 450 μm map allows us to make a detailed analysis of the temperature and column density profiles of the core. We find that the dust temperature at the center of TMC-1C is ~7 K, rising to ~11 K at the edges. We discuss the possibility and effects of a variable emissivity spectral index on the derived mass profile. The low dust temperature of TMC-1C results in a high derived mass for the core, significantly larger than the virial mass estimated from the line width of the N2H+ (1-0) transition. This result is valid within a wide range of dust properties and ellipticities of the core. The N2H+ (1-0) spectra, taken with the IRAM 30 m telescope, show signs of self-absorption, which provide evidence of subsonic infall motions. The derived density profile and infall velocity are compared to the predictions of several popular star formation models, and the Bonnor-Ebert model is the best-fit analytic model.
Partial Zeta Functions of Algebraic Varieties over Finite Fields

Motivated by arithmetic applications, we introduce the notion of a partial zeta function which generalizes the classical zeta function of an algebraic variety defined over a finite field. We then explain two approaches to the general structural properties of the partial zeta function in the direction of the Weil-type conjectures. The first approach, using an inductive fibred variety point of view, shows that the partial zeta function is rational in an interesting case, generalizing Dwork's rationality theorem. The second approach, due to Faltings, shows that the partial zeta function is always nearly rational.
The Status of Women in Archeology

Earlier studies, such as those cited in Roger Sanjek's seminal Signs article, clearly show that women anthropologists traditionally tend to have lower status than men. Suspecting that this might be the case in archeology as well as in anthropology more generally, our objective was to identify areas in which differences between the sexes might be empirically expressed. Selected observations regarding archeology PhD recipients, patterns in funding or preand post-doctoral level archeologists and faculty composition in major departments suggest that in the US doctorates, research grants and prestigious academic appointments are differentially acquired by male and female archeologists. Using longitudinal data covering the period 1976-1986, we offer the following observations: 1. More men than women receive the PhD in anthropological archeology. Data reviewed below neither support nor refute the hypothesis that this difference exists regardless of size and sex composition of entering student cohorts. Establishing causal relationships between discrimination against students and students' sex would require detailed longitudinal quantitative as well as qualitative documentation from a number of departments, which we lack. We note, however, that data from the 1976-86 AAA Guide clearly demonstrate that throughout this decade women have constituted about half of all anthropology graduate students in the departments shown in Table 1.
A comparison between ultrasonography and laparoscopy in localising the impalpable undescended testis.

Summary— in 11 boys, 3 of whom had bilateral and 8 unilateral impalpable testes, ultrasonography was used to identify the location of the testes. The results of ultrasonography are compared with those of laparoscopy in the same patients. The testes were absent in two instances. The remaining 12 testes were accurately located by laparoscopy. Ultrasonography demonstrated the testes in only two cases.
An Enantioselective Claisen Rearrangement Catalyzed by N-Heterocyclic Carbenes

In the presence of a chiral azolium salt (10 mol %), enols and ynals undergo a highly enantioselective annulation reaction to form enantiomerically enriched dihydropyranones via an N-heterocyclic carbene catalyzed variant of the Claisen rearrangement. Unlike other azolium-catalyzed reactions, this process requires no added base to generate the putative NHC-catalyst, and our investigations demonstrate that the counterion of the azolium salt plays a key role in the formation of the catalytically active species. Detailed kinetic studies eliminate a potential 1,4-addition as the mechanistic pathway; the observed rate law and activation parameters are consistent with a Claisen rearrangement as the rate-limiting step. This catalytic system was applied to the synthesis of enantioenriched kojic acid derivatives, a reaction of demonstrated synthetic utility for which other methods for catalytic enantioselective Claisen rearrangements have not provided a satisfactory solution.
Classical symmetries of some two-dimensional models

Abstract It is well-known that principal chiral models and symmetric space models in two-dimensional Minkowski space have an infinite-dimensional algebra of hidden symmetries. Because of the relevance of symmetric space models to duality symmetries in string theory, the hidden symmetries of these models are explored in some detail. The string theory application requires including coupling to gravity, supersymmetrization, and quantum effects. However, as a first step, this paper only considers classical bosonic theories in flat space-time. Even though the algebra of hidden symmetries of principal chiral models is confirmed to include a Kac-Moody algebra (or a current algebra on a circle), it is argued that a better interpretation is provided by a doubled current algebra on a semi-circle (or line segment). Neither the circle nor the semi-circle bears any apparent relationship to the physical space. For symmetric space models the line segment viewpoint is shown to be essential, and special boundary conditions need to be imposed at the ends. The algebra of hidden symmetries also includes Virasoro-like generators. For both principal chiral models and symmetric space models, the hidden symmetry stress tensor is singular at the ends of the line segment.
KECK HIRES SPECTROSCOPY OF CANDIDATE POST T TAURI STARS

We use high signal-to-noise ratio (~150-450), high-resolution (R ~ 45,000) Keck HIRES spectroscopy of 13 candidate post-T Tauri stars (PTTs) to derive basic physical parameters, lithium abundances, and radial velocities. We place our stars in the Mv-Teff plane for use in determining approximate ages from pre-main-sequence isochrones, and we confirm these using three relative age indicators in our analysis: Li abundances, chromospheric emission, and the kinematic U-V plane. Using the three age criteria we identify five stars (HIP 54529, HIP 62758, HIP 63322, HIP 74045, and HIP 104864) as probable PTTs with ages between 10 and 100 Myr. We confirm HIP 54529 as an SB2 star and HIP 63322 as an SB1 star. We also examine irregular photometric variability of PTTs using the Hipparcos photometry annex. Two of our PTTs exhibit near-IR excesses compared to Kurucz model flux; while recent work suggests classical T Tauri stars evince similar JHK excesses presumably indicative of nonphotospheric (disk) emission, our results may be illusory artifacts of the chosen I-band normalization. The near-IR excesses we see in a literature-based sample of PTTs appear to be artifacts of previous spectral type-based Teff values. Indeed, comparison of the homology of their observed and model photospheric spectral energy distributions suggests that photometric temperatures are more reliable than temperatures based on spectral standards for the cooler temperature ranges of the stars in this sample. We conclude that our age-oriented analysis is a robust means to select samples of nearby, young, isolated PTTs that otherwise masquerade as normal field stars.
The Impact of E‐Commerce Strategies on Firm Value: Lessons from Amazon.com and Its Early Competitors*

Which strategies generate value in e‐commerce environments? In a step toward answering this question, this article estimates the impacts of several competitive strategies on the values of the well‐known Internet retailer Amazon.com and three of its early competitors, BarnesandNoble.com, CDNOW, and N2K, from their IPO dates until exit or the end of 2001. The strategies analyzed include alliance formation, offline expansion, pricing, product line expansion, and service improvement. The results provide insight into the usefulness of various ways of competing online and could be applied in other settings where firms enter new environments about which they have little information.
Coronal X-Ray Emission from the Stellar Companions to Transiently Accreting Black Holes

Many neutron stars and black holes are in binaries where the mass transfer rate onto the compact object is highly variable. X-ray observations of these transients in quiescence (LX < 1034 ergs s-1) have found that the binaries harboring black holes are much fainter than those that contain a neutron star. Narayan and collaborators postulated that the faint X-ray emission from black hole binaries was powered by an advection- dominated accretion flow (ADAF). The subsequent ADAF modeling requires that an appreciable fraction of the constant Roche-lobe overflow into the outer disk proceeds into the black hole during "quiescence". A robust and nearly uniform quenching mechanism must then be hypothesized for the neutron star binaries, as comparably large accretion rates would lead to luminosities in excess of 1036 ergs s-1 in quiescence. We explore an alternative explanation for the quiescent X-ray emission from the black hole systems: coronal emission from the rapidly rotating optical companion. This is commonly observed and well studied in other tidally locked binaries, such as the RS CVn, Algol, and By Dra systems. We show that two of the three X-ray detected black hole binaries (A0620-00 and GRO J1655-40) exhibit X-ray fluxes entirely consistent with coronal emission. The X-ray spectra of these objects should be best fitted with thermal Raymond-Smith models rich in lines when coronal emission predominates, a prediction that will be tested with Chandra and XMM-Newton observations. One black hole system (V404 Cyg) is too X-ray bright to be explained as coronal emission and remains a candidate for ADAFs in quiescence. The quiescent X-ray emission from all the neutron star binaries is far too bright for coronal emission. It might be that all soft X-ray transients have variable accretion rates in quiescence and that the basal quiescent X-ray flux is set by either coronal emission from the companion or—when present—by thermal emission from the neutron star. We have also searched for other indicators of coronal activity in these companion stars. For example, we show that the lithium abundances in the black hole systems are comparable to those in the RS CVns. Indeed, both the X-ray flux and lithium abundance from the K star in the binary V471 Tau match that of A0620-00. Though the production mechanisms for lithium in active coronae is still under debate, our work makes it clear that there is no longer a need for mechanisms that involve the compact object.
Pediatric central corneal thickness variation among major ethnic populations.

Purpose: To investigate differences in central corneal thickness (CCT) among African-American, Caucasian, and Hispanic pediatric populations with respect to race, age, and gender. Subjects and methods: Ultrasound pachymetry measurements were obtained on 208 eyes of 106 patients. Measurements from left eyes were used in data analysis. Analysis of variance (ANOVA) and two-tailed t -test were performed to determine the effect of race, age, and gender on CCT variation. Results: Mean central corneal thickness of left eyes in each ethnic group was African-Americans, 523 ± 40 μm; Caucasians, 563 ± 36 μm; and Hispanics, 568 ± 44 μm. ANOVA performed on pachymetry values showed a significant effect of race on CCT ( P = 0.00002). Mean Hispanic CCT was greater than mean African-American CCT ( P = 0.0003), but was not significantly different from Caucasian CCT ( P = 0.56). Mean Caucasian CCT was also greater than mean African-American CCT ( P = 0.0001). The difference between mean male CCT (548 ± 41 μm) and mean female CCT (563 ± 44 μm) did not reach statistical significance ( P = 0.07). When patients were stratified into age groups ( P = 0.16). Conclusions: Our study suggests there may be differences in CCT among different ethnic groups in the pediatric population, with African-Americans having thinner corneas than Caucasians and Hispanics.
Thin film molybdenum silicide as potential temperature sensors for turbine engines

Abstract Temperature measurements of Mo−Si-based thin-film resistance thermometers were studied. Annealing in an argon ambient at a temperature above 1000 °C for at least 1 h is required to form the stable tetragonal MoSi 2 phase. With a crack-free AlN barrier layer of thickness 2μm on top, a sensor was tested up to 1200 °C. The resistivity vs . temperature characteristic shows the room temperature resistivity and temperature coefficient of resistivity (TCR) of the sensor to be approximately 350 μΩ and 11.95×10 -3 K respectively. No film adhesion problems were observed for at least four testing cycles.
Arrhythmias documented by 24 hour continuous electrocardiographic monitoring in 50 male medical students without apparent heart disease.

Results are reported of portable 24 hour dynamic electrocardiographic monitoring in 50 male medical students without cardiovascular disease, as defined by normal clinical and noninvasive cardiovascular examination. During waking periods, maximal sinus rates ranged from 107 to 180 beats/min (mean ± standard deviation 141 ± 17) and minimal rates from 37 to 65 beats/min (mean 53 ± 6). Maximal and minimal observed sleeping rates were, respectively, 70 to 115 (mean 86 ± 9) and 33 to 55 (mean 43 ± 5). Twenty-five subjects (50 percent) had episodes of marked sinus arrhythmia as defined by spontaneous changes in adjacent cycle lengths of 100 percent or more. Fourteen subjects (28 percent) had sinus pauses of more than 1.75 seconds, usually during sinus arrhythmia. Transient nocturnal type I second degree atrioventricular (A-V) block was noted in three subjects (6 percent). Of 28 patients (56 percent) having atrial premature beats, only 1 (2 percent) had more than 100 such beats (141) in 24 hours. Of 25 patients (50 percent) having premature ventricular contractions, only 1 (2 percent) had more than 50 such contractions (86) in 24 hours. In conclusion, frequent atrial and ventricular premature beats are unusual in a young adult male population. In contrast, bradyarrhythmias (including marked sinus arrhythmia with sinus pauses, sinus bradycardia and nocturnal A-V block) are common. These findings are useful in evaluating the clinical significance of arrhythmias detected with portable monitoring.
Cycloadditions of methyl dichloroacetate to electrophilic alkenes

Abstract Seven MIRC reactions of methyl dichloroacetate with alkenes containing electron-withdrawing groups were used to make 1-chlorocyclopropanecarboxylates.
A series of normal stages in the development of the chick embryo

FORTY-FIVE FIGURES The preparation of a series of normal stages of the chick embryo does not need justification at a time when chick ernbryos are not only widely used in descriptive and experimental embryology but are proving to be increasingly valuable in medical research, as in work on viruses and cancer. The present series was planned in connection with the preparation of a new edition of Lillie’s DeueZopmerzt of the Chick by the junior author. It is being published separately to make it accessible immediately to a large group of workers. Ever since Aristotle “discovered” the chick embryo as the ideal, object for embryological studies, the embryos have been described in terms of the length of time of incubation, and this arbitrary method is still in general use, except for the first three days of incubation during which more detailed characteristics such as the numbers of somites are applied. The shortcomings of a classification based on chronological age are obvious to every worker in this field, for enormous variations may occur in embryos even though all eggs in a setting are plmaced in the incubator at the same time. Many factors are responsible for the lack of correlation between chronological and structural age. Among these are : genetic differences in the rate of development of different breccls (eg., the embryo of the White Leghorn breed develops more 49
Spectrophotometric studies of californium(III) ions in selected lanthanide trihalide hosts

Abstract The solid-state absorption spectra of the californium(III) ion as a dopant in a variety of lanthanide trihalide host matrices were recorded. The host matrices were chosen on the basis of both their crystal structures and optical windows. X-ray powder diffraction analysis was performed to ensure that each host exhibited the expected crystal structure. The absorption spectra of the californium(III) ion in each matrix were correlated with the various crystal structures to support the use of solid state absorption spectrophotometry as a probe for the identification of crystal structure.
GENERAL ASYMMETRIC SYNTHESIS OF HYDROXYMETHYLENE AND HYDROXYETHYLENE PEPTIDE ISOSTERES

Abstract The Lewis acid-promoted coupling reactions of (5 R , 6 S )-2-acetoxy-4-(benzyloxycarbonyl)-5,6-diphenyl-2,3,5,6-tetrahydro-4H-1,4-oxazines ( 11a-e , and 21 ), which are prepared easily from (+-(5R, 6S)-4-( benzyloxycarbonyl)-5,6-diphenyl-2,3,5,6-tetrahydro-4H-1,4-oxazin-2-one ( 9 ) , with allyltrimethylsilane proceeded to give the corresponding coupling products with moderate to excellent stereoselectivity in good yields. These coupling products ( 13a, b , and d ) were converted to hydroxymethylene- ( 25a, b , and d ) and hydroxyethylene ( 28 ) peptide isosteres.
Phenomenology of charm and bottom production

We discuss the renormalization and factorization scale dependence of charm and bottom production both at fixed-target energies and at present and future colliders. We investigate whether distributions calculable at leading order can be extrapolated to next-to-leading order by a constant multiplicative factor.
Certain extensions of vertex operator algebras of affine type

We generalize Feigin and Miwa's construction of extended vertex operator (super)algebras A k (sl(2)) for other types of simple Lie algebras. For all the constructed extended vertex operator (super)algebras, irreducible modules are classified, complete reducibility of every module is proved and fusion rules are determined modulo the fusion rules for vertex operator algebras of affine type.
Dynamically excited outer solar system objects in the Hubble Space Telescope archive

We present the faintest mid-ecliptic latitude survey in the second part of Hubble Space Telescope archival search for outer solar system bodies. We report the discovery of 28 new trans-Neptunian objects and one small centaur (R {approx} 2 km) in the band 5 Degree-Sign -20 Degree-Sign off the ecliptic. The inclination distribution of these excited objects is consistent with the distribution derived from brighter ecliptic surveys. We suggest that the size and inclination distribution should be estimated consistently using suitable surveys with calibrated search algorithms and reliable orbital information.
Observational Signatures of the First Quasars

We study the observational signatures of a potential population of low-luminosity quasars at high redshifts in a ΛCDM cosmology. We derive the evolution of the quasar luminosity function at fainter luminosities and higher redshifts than currently detected based on three assumptions: (1) the formation of dark matter halos follows the Press-Schechter theory, (2) the ratio of central black hole mass to halo mass is the same for all halos, and (3) the light curve of quasars, in Eddington units, is universal. We show that a universal light curve provides an excellent fit to the observed quasar luminosity function at redshifts 2.6 10 with its proposed 1 nJy sensitivity at 1-3.5 μm. Absorption spectra of several such quasars would reveal the reionization history of the universe.
Observations on the hydrogen peroxide-iodic acid-manganese(II)-organic species oscillating system

The effect of acidity and manganese (II) concentration on the title reaction has been examined for acetone and malonic acid as the organic species. Cerium (III) has been shown to replace manganese (II) without loss of the oscillatory behavior. Some mechanistic details are given.
Rheological implications of the internal structure and crystal fabrics of the West Antarctic ice sheet as revealed by deep core drilling at Byrd Station

Crystalline textures and fabrics of ice cores from the 2,164-m-thick ice sheet at Byrd Station, Antarctica, reveal the existence of an anisotropic ice sheet. A gradual but persistent increase in the c -axis preferred orientation of the ice crystals was observed between the surface and a depth of 1,200 m. This progressive growth of an oriented crystal fabric is accompanied by a twentyfold increase in crystal size between 56 and 600 m, followed by virtually no change in crystal size between 600 and 1,200 m depth. A broad vertical clustering of c axes develops by 1,200 m. Between 1,200 and 1,300 m, the structure transforms into a fine-grained mosaic of crystals with their basal glide planes now oriented substantially within the horizontal. This highly oriented fine-grained structure, which persists to 1,800 m depth, is compatible only with a strong horizontal shear deformation in this part of the ice sheet. Rapid transformation from single- to multiple-maximum fabrics occurs below 1,800 m. This transformation, accompanied also by the growth of very large crystals, is attributed to the overriding effect of relatively high temperatures in the bottom layers of old ice at Byrd Station rather than to a significant decrease in stress. The zone of single-maximum fabrics between 1,200 and 1,800 m also contains numerous layers of volcanic dust. Fabrics of the very fine grained ice associated with these dust bands indicate that the bands are actively associated with shearing in the ice sheet. Some slipping of ice along the bed rock seems likely at Byrd Station, since the basal ice is at the pressure melting point and liquid water is known to exist at the ice-rock interface. The textures and fabrics of the ice indicate that plastic deformation (intracrystalline glide) in the zone of strong single-maximum fabrics and movement of ice along discrete shear planes situated well above bed rock are also major contributors to the flow of the ice sheet. Any extensive shearing at depth could seriously distort stratigraphic records contained in the ice cores, such as climatic history as inferred from stable isotope analysis. Also, the common practice of using simplified flow models to approximate the depth-age relationships of deep ice-sheet cores may need to be revised in light of the deformational features and fabrics observed in the Byrd Station ice cores.
Delay equations and radiation damping

Abstract Starting from delay equations that model field retardation effects, we study the origin of runaway modes that appear in the solutions of the classical equations of motion involving the radiation reaction force. When retardation effects are small, we argue that the physically significant solutions belong to the so-called slow manifold of the system and we identify this invariant manifold with the attractor in the state space of the delay equation. We demonstrate via an example that when retardation effects are no longer small, the motion could exhibit bifurcation phenomena that are not contained in the local equations of motion.
The Dielectric Properties of Water for Continuous Waves

Direct measurement of the refractive index of water for continuous waves of length about 2 meters.---In the method adopted continuous standing waves on wires were measured both in air and in water, and the refractive index determined as the ratio. Errors involved in the measurement of the length of waves in air due to imperfect reflection and to the resistance of the guiding wires, were investigated. In the case of water it was found that measurements varied with the size of the tank unless the waves were guided into the water by conductors extending through the tank. The final arrangement is analogous to Kundt's tube for sound waves; the level of the water in a vertical tube through which the parallel wires passed, was varied and the nodes determined from the variation of the current from a thermocouple placed in the bridge of the Lecher system, located at the lower end of the water column. Thus a number of nodes were located. The mean result for the refractive index comes out 8.88\ifmmode\pm\else\textpm\fi{}.04, in good agreement with values obtained by others using discontinuous waves. This indicates that within the range of frequencies investigated, the group velocity of waves through water is the same as their phase velocity, within the accuracy of the measurements. No appreciable dispersion for the range of wave-lengths 124 and 276 cm was observed.An oscillating circuit for producing short continuous Hertzian waves of length varying from 1 meter up, is described, in which the tube capacity is used as a means of coupling.
The Economic Impact of Armed Conflict in Rwanda

The human, social and economic costs of Rwanda's genocide have been staggering. The losses in life cannot be reversed and the psychological impact of the violence will take a long time to heal. The country has made remarkable progress over the last 10 years to get back to where it would have been without the conflict--for example, in terms of trends for basic education and health indicators such as primary enrollment and child mortality. Yet GDP per capita remains much lower than what it would have been without the genocide. The paper proposes a methodology for the estimation and correction of extreme values or outliers and estimates that per capita GDP today would probably be between 25 and 30% higher if the conflict had not taken place. Copyright 2005, Oxford University Press.
Metal-Free Catalytic Enantioselective C–B Bond Formation: (Pinacolato)boron Conjugate Additions to α,β-Unsaturated Ketones, Esters, Weinreb Amides and Aldehydes Promoted by Chiral N-Heterocyclic Carbenes

The first broadly applicable metal-free enantioselective method for boron conjugate addition (BCA) to α,β-unsaturated carbonyls is presented. The C–B bond forming reactions are promoted in the presence of 2.5–7.5 mol % of a readily accessible C1-symmetric chiral imidazolinium salt, which is converted, in situ, to the catalytically active diastereo- and enantiomerically pure N-heterocyclic carbene (NHC) by the common organic base 1,8-diazabicyclo[5.4.0]undec-7-ene (dbu). In addition to the commercially available bis(pinacolato)diboron [B2(pin)2], and in contrast to reactions with the less sterically demanding achiral NHCs, the presence of MeOH is required for high efficiency. Acyclic and cyclic α,β-unsaturated ketones, as well as acyclic esters, Weinreb amides, and aldehydes, can serve as suitable substrates; the desired β-boryl carbonyls are isolated in up to 94% yield and >98:2 enantiomer ratio (er). Transformations are often carried out at ambient temperature. In certain cases, such as when the relative...
Quorum consensus in nested-transaction systems

Gifford's Quorum Consensus algorithm for data replication is studied in the context of nested transactions and transaction failures (aborts), and a fully developed reconfiguration strategy is presented. A formal description of the algorithm is presented using the Input/Output automaton model for nested-transaction systems due to Lynch and Merritt. In this description, the algorithm itself is described in terms of nested transactions. The formal description is used to construct a complete proof of correctness that uses standard assertional techniques, is based on a natural correctness condition, and takes advantage of modularity that arises from describing the algorithm as nested transactions. The proof is accomplished hierarchically, showing that a fully replicated reconfigurable system “simulates” an intermediate replicated system, and that the intermediate system simulates an unreplicated system. The presentation and proof treat issues of data replication entirely separately from issues of concurrency control and recovery.
Isoxazoline GPIIb/IIIa antagonists bearing a phosphoramidate

Isoxazolinylacetamides bearing a phosphoramidate group α- to the carboxylate moiety (3) were prepared and evaluated for in vitro antiplatelet efficacy. They were found to bind GPIIb/IIIa with high affinity and were potent antagonists of ADP mediated platelet aggregation.
Monetary Policy and the Housing Bubble

The causes of the housing bubble are investigated using Granger causality analysis and VAR modeling methods. The study employs the S&P/Case-Shiller aggregate 10 city monthly housing price index, available in the period 1987–2010/8, the 20 city monthly housing price index for 2000–2010/8, and the federal funds rate data for the period 1987–2010/8. The findings are consistent with the view that the interest rate policy of the Federal Reserve in the period 2001–2004 that pushed down the federal funds rate and kept it artificially low was a cause of the housing price bubble.
Partition functions of chiral gauge theories on the two dimensional torus and their duality properties

Abstract Two different families of abelian chiral gauge theories on the torus are investigated: the aim is to test the consistency of two-dimensional anomalous gauge theories in the presence of global degrees of freedom for the gauge field. An explicit computation of the partition functions shows that unitarity is recovered in particular regions of parameter space and that the effective dynamics is described in terms of fermionic interacting models. For the first family, this connection with fermionic models uncovers an exact duality which is conjectured to hold in the nonabelian case as well.
NEW RING SYSTEMS FROM 1,2-BENZISOTHIAZOLE-1,1-DIOXIDES AND RELATED COMPOUNDS

Abstract Ring-expansions and ring-annulations based on 3-substituted 1,2-benzisothiazole-1,1-dioxides have lead to a variety of novel heterocyclic systems. The reaction of 3-substituted (1 H )-1-isoindolones with 1-diethylamino-1-propyne has also resulted in new, ring-expanded molecules in good to modest yields.
Machine learning attacks against the Asirra CAPTCHA

The Asirra CAPTCHA [EDHS2007], proposed at ACM CCS 2007, relies on the problem of distinguishing images of cats and dogs (a task that humans are very good at). The security of Asirra is based on the presumed difficulty of classifying these images automatically.In this paper, we describe a classifier which is 82.7% accurate in telling apart the images of cats and dogs used in Asirra. This classifier is a combination of support-vector machine classifiers trained on color and texture features extracted from images. Our classifier allows us to solve a 12-image Asirra challenge automatically with probability 10.3%. This probability of success is significantly higher than the estimate of 0.2% given in [EDHS2007] for machine vision attacks. Our results suggest caution against deploying Asirra without safeguards.We also investigate the impact of our attacks on the partial credit and token bucket algorithms proposed in [EDHS2007]. The partial credit algorithm weakens Asirra considerably and we recommend against its use. The token bucket algorithm helps mitigate the impact of our attacks and allows Asirra to be deployed in a way that maintains an appealing balance between usability and security. One contribution of our work is to inform the choice of safeguard parameters in Asirra deployments.
Oblique central refraction in spherocylindrical corrections with both faceform and pantoscopic tilt

Thin lens equations, accurate to third order, are presented for the effective spherocylindrical parameters for oblique central refraction (OCR) through spherocylindrical lenses with both faceform and pantoscopic tilt. The equations can also be used to find the parameters of a lens that compensates for the tilts. Accuracy of the equations was checked by exact ray trace results.
Individual Characteristics and the Disposition Effect: The Opposing Effects of Confidence and Self-Regard

We conduct two experiments to examine potential causes of the disposition effect. In Experiment 1, we rule out beliefs in mean reversion as a cause of the disposition effect. Although a belief in the mean reversion of stock prices should be independent of whether an investor owns or only follows the stock, we show only investors who own the stock behave as though prices will reverse. In Experiment 2, participants buy and sell securities over multiple periods. We find that self-regard and investing confidence (two types of self-esteem) have opposing influences on investors’ tendency to hold losing investments. Investors with lower self-regard hold losing investments longer than those with higher self-regard, and investors with higher confidence hold losing investments longer than those with lower confidence. We focus on investors’ tendency to hold losing stocks too long because prior research suggests the gain versus loss sides of the disposition effect are driven by different biases.
Sensing metabolic activity in tissue engineered constructs

Tissue engineered constructs can be employed to graft wounds or replace diseased tissue. Non-invasive methods are required to assess cellular viability in these constructs both pre- and post- implantation into patients. In this study, Monte Carlo simulations and fluorescence experiments were executed on ex vivo produced oral mucosa equivalent (EVPOME) constructs to investigate the fluorescence emitted at 355 nm excitation from these constructs. Both simulations and experiments indicated the need to investigate alternative excitation wavelengths in order to increase the cellular fluorescence from these constructs, while decreasing contributions from extra-cellular fluorophores.
HD 101088, AN ACCRETING 14 AU BINARY IN LOWER CENTAURUS CRUX WITH VERY LITTLE CIRCUMSTELLAR DUST ∗

We present high-resolution (R = 55, 000) optical spectra obtained with MIKE on the 6.5 m Magellan Clay Telescope as well as Spitzer MIPS photometry and Infrared Spectrometer low-resolution (R ~ 60) spectroscopy of the close (14 AU separation) binary, HD 101088, a member of the ~12 Myr old southern region of the Lower Centaurus Crux subgroup of the Scorpius-Centaurus OB association. We find that the primary and/or secondary is accreting from a tenuous circumprimary and/or circumsecondary disk despite the apparent lack of a massive circumbinary disk. We estimate a lower limit to the accretion rate of 1\times 10^{-9} \;M_{\odot } \;{\rm yr}^{-1}$ SRC=http://ej.iop.org/images/0004-637X/714/2/1542/apj342600ieqn1.gif/>, which our multiple observation epochs show varies over a timescale of months. The upper limit on the 70 μm flux allows us to place an upper limit on the mass of dust grains smaller than several microns present in a circumbinary disk of 0.16 M moon. We conclude that the classification of disks into either protoplanetary or debris disks based on fractional infrared luminosity alone may be misleading.
On the dynamical reduction of the Vlasov equation

Abstract The elimination of a fast-time scale from the Vlasov equation by Lie-transform methods is an important step in deriving a reduced Vlasov equation such as the drift-kinetic Vlasov equation or the gyrokinetic Vlasov equation. It is shown here that this dynamical reduction also leads to the introduction of polarization and magnetization effects in the reduced Maxwell equations, which ensure that the reduced Vlasov–Maxwell equations possess an exact energy–momentum conservation law.
Market Structure and Performance of U.S. Multinationals in Brazil and Mexico

This paper presents the results of a regression analysis of the market structure determinants of profitability among the Brazilian and Mexican manufacturing affiliates of US multinational corporations. The study employs data on 206 firms derived from a special survey specifically designed to obtain detailed information on their market structure environments and performance characteristics. Our estimates confirm that seller concentration, product differentiation, and relative market share are three sources of market power of these firms. Despite the many economic and noneconomic differences between Brazil and Mexico, there are no systematic differences between the two in their underlying structure‐performance relationships.
Real and monetary determinants of real exchange rate behavior: Theory and evidence from developing countries☆

Abstract This paper develops a dynamic model of real exchange rate (RER) behavior in developing countries. A three goods economy (exportables, importables and non-tradables) is considered. Residents of this country hold domestic and foreign assets, and there is a dual exchange rate regime. There is a government that consumes importables and non-tradables. A distinction is made between equilibrium and disequilibrium movements of the RER. The determinants of real exchange rate misalignment are studied with emphasis placed on the role of devaluations and balance of payments crises. The implications of the model are tested using data for 12 developing countries. The results obtained are generally favorable for the model. The issue of RER stationarity is also analyzed.
The complexity of processing hierarchical specifications

Hierarchical object descriptions consisting of a set of module descriptions are considered, where each module is either a primitive module or has a body that is an interconnection of submodules. The description represents a flattened object, whose size can be exponential in the size of the description. The complexity of processing and/or analyzing such hierarchically specified objects is considered. The simulation of hierarchically specified circuits is emphasized, but the results are applicable to other kinds of hierarchically specified objects.
Tandem arylation-reduction of acyl heterocycles. Convenient synthesis of benzyl heterocycles

Tandem arylation-reduction of a series of acyl heterocycles using phenyl-, 4-methylphenyl-, and 4-methoxy-phenyllithium reagents followed by lithium-ammonia-ammonium chloride reduction afforded the corresponding benzyl heterocycles. The acyl heterocycles surveyed in this study contained furan, 2,3-dihydro-4H-1-benzopyran, 4H-1-benzopyran, thiophene, 4,5,6,7-tetrahydrobenzo[b]thiophene, 2,3-dihydro-4H-1-benzothiopyran, and pyridine nuclei. All acyl heterocycles yielded the corresponding benzyl heterocycles except 2,3-dihydro-4H-1-benzothiopyran-4-one, which selectively cleaved during reduction to give the corresponding 2-(1-arylpropyl)benzenethiols.
Formulæ for the number of partitions of n into at most m parts (using the quasi-polynomial ansatz)

The purpose of this short article is to announce, and briefly describe, a Maple package, PARTITIONS, that (inter alia) completely automatically discovers, and then proves, explicit expressions (as sums of quasi-polynomials) for p"m(n) for any desired m. We do this to demonstrate the power of ''rigorous guessing'' as facilitated by the quasi-polynomial ansatz.
Combining physician's subjective and physiology-based objective mortality risk predictions.

ObjectiveNone of the currently available physiology-based mortality risk prediction models incorporate subjective judgements of healthcare professionals, a source of additional information that could improve predictor performance and make such systems more acceptable to healthcare professionals. Thi