cssi/SciSciGPT-SciSciNet huggingface dataset:
ALE Ricci-flat Kähler metrics and deformations of quotient surface singularities

Let $${N_0={\mathbb C}^2/H}$$ be an isolated quotient singularity with $${H\subset U(2)}$$ a finite subgroup. We show that for any $${\mathbb Q}$$ -Gorenstein smoothings of N 0 a nearby fiber admits ALE Ricci-flat Kahler metrics in any Kahler class. Moreover, we generalize Kronheimer’s results on hyperkahler 4-manifolds (J Differ Geom 29(3):685–697, 1989), by giving an explicit classification of the ALE Ricci-flat Kahler surfaces. We construct ALF Ricci-flat Kahler metrics on the above non-simply connected manifolds. These provide new examples of ALF Ricci-flat Kahler 4-manifolds, with cubic volume growth and cyclic fundamental group at infinity.
Effects of aging on polyimide : a study of bulk and interface chemistry

We are investigating the bulk and interfacial chemistry of polyimide (PI) exposed to heat and relative humidity (RH) stress (85°C/85% RH) over long periods to understand the long-term reliability aspects of PI for microelectronic applications. The PI surface chemistry and the PI–Si interface chemistry was followed with electron spectroscopy for chemical analysis (ESCA). For exposure times greater than 550 h, the PI surface exhibits significant changes in emission structure and atomic concentration. The PI–Si interface indicates little change in the PI chemistry when compared to control samples. The water-contact angle at the PI surface shows no statistically significant change as a function of exposure time. Bulk and surface chemistry were followed with Fourier transform infrared spectroscopy (FTIR) in a grazing incidence reflection configuration. There were measurable differences in FTIR spectra between aged and control samples only for the case of very thin PI layers. These results suggest that for exposure times of less than 1100 h, chemical changes in PI occur primarily at the PI–air interface for samples 1 μm thick and greater. These changes represent a possible rearrangement of the imide structure and may be a form of deimidization of the polymer, but the final state is not polyamic acid. The PI surface chemistry changes observed with ESCA are reversible upon reheating to the cure temperature.
On channels with action-dependent states

Action-dependent channels model scenarios in which transmission takes place in two successive phases. In the first phase, the encoder selects an “action” sequence, with the twofold aim of conveying information to the receiver and of affecting in a desired way the state of the channel to be used in the second phase. In the second phase, communication takes place in the presence the mentioned action-dependent state. In this work, two extensions of the original action-dependent channel are studied. In the first, the decoder is interested in estimating not only the message, but also the state sequence within an average per-letter distortion. Under the constraint of common reconstruction (i.e., the decoder's estimate of the state must be recoverable also at the encoder) and assuming non-causal state knowledge at the encoder in the second phase, we obtain a single-letter characterization of the achievable rate-distortion-cost trade-off. In the second extension, we study an action-dependent degraded broadcast channel. Under the assumption that the encoder knows the state sequence causally in the second phase, the capacity-cost region is identified. Various examples, including Gaussian channels and a model with a “probing” encoder, are also provided to show the advantage of a proper joint design of the two communication phases.
The Impact of Race on Advanced Chronic Venous Insufficiency.

Background The study aimed to determine the association between race and patient variables, hospital covariates, and outcomes in patients presenting with advanced chronic venous insufficiency. Methods The National Inpatient Sample was queried to identify all Caucasian and African-American patients with a primary International Classification of Diseases, Ninth Revision (ICD-9) diagnosis code for venous stasis with ulceration (454.0), inflammation (454.1), or complications (454.2) from 1998 to 2011. CEAP scores were correlated with ICD-9 diagnosis. Demographics, CEAP classification, management, cost of care, length of stay (LOS), and inpatient mortality were compared between races. Statistical analysis was via descriptive statistics, Student’s t-test, and the Fisher’s exact test. Trend analysis was completed using the Mann–Kendall test. Results A total of 20,648 patients were identified of which 85% were Caucasian and 15% were African-American. Debridement procedures had the highest costs at $6,096 followed by skin grafting at $4,089. There was an overall decrease in the number of ulcer debridements, vein stripping, and sclerotherapy procedures between 1998 and 2011 (P Conclusions African-American patients with a primary diagnosis of venous stasis present with more advanced venous disease at a younger age compared with their Caucasian counterparts. This is associated with increased ulcer debridement, deep vein thrombosis rates and hospital charges in the African-American cohort. There are no differences in sclerotherapy or skin grafting procedures, LOS or inpatient mortality between races.
Secular and Islamic feminist entrepreneurship in Turkey

Purpose – This paper aims to highlight secular and Islamic feminist approaches to entrepreneurship as potential means to challenge gender inequality in the Turkish context. In Turkey, gender equality remains elusive in a nation where secular and Islamic ideologies compete and produce different solutions to ongoing economic, socio-cultural and political issues. Women’s entrepreneurship has emerged as an important solution toward gender equality and economic development. Design/methodology/approach – Using two women’s organizations that exemplify secular and Islamic feminist ideologies, the author examines whether the entrepreneurship activities they promote give way to challenging patriarchal norms, values and practices widespread in Turkish society. Findings – Through their distinct practices and engagement with entrepreneurship, both secular and Islamic feminist positions allow for praxis and represent an ethico-political commitment to dismantling neo-liberal development ideologies in the Turkish context...
Efficiently Hex-Meshing Things with Topology

A topological quadrilateral mesh $$Q$$Q of a connected surface in $$\mathbb {R}^3$$R3 can be extended to a topological hexahedral mesh of the interior domain $$\varOmega $$Ω if and only if $$Q$$Q has an even number of quadrilaterals and no odd cycle in $$Q$$Q bounds a surface inside $$\varOmega $$Ω. Moreover, if such a mesh exists, the required number of hexahedra is within a constant factor of the minimum number of tetrahedra in a triangulation of $$\varOmega $$Ω that respects $$Q$$Q. Finally, if $$Q$$Q is given as a polyhedron in $$\mathbb {R}^3$$R3 with quadrilateral facets, a topological hexahedral mesh of the polyhedron can be constructed in polynomial time if such a mesh exists. All our results extend to domains with disconnected boundaries. Our results naturally generalize results of Thurston, Mitchell, and Eppstein for genus-zero and bipartite meshes, for which the odd-cycle criterion is trivial.
Fuel Spray Evolution: Comparison of Experiment and CFD Simulation of Nonevaporating Spray

Detailed spray characteristics were obtained for a small-capacity, pressure-swirl atomizer using an Aerometrics phase-Doppler particle analyzer. Measurements included drop size and velocity distributions, liquid volume fluxes, and air velocities at four axial locations, 25,50,75, and 100 mm, with complete radial traverses at each location. Drop size results were compared with measurements from a Malvern laser-diffraction instrument, and integrated liquid volume fluxes were compared with measured flow rates to estimate measurement uncertainties. Drop sizes measured by the two independent techniques and area-weighted-averaged over the radial traverses at each of the four axial stations varied on average by less than 4 percent. Integrated volume flux measurements by the phase-Doppler instrument at four axial stations differed from the nozzle flow rate by at most 19 percent, with some of the difference due to evaporation. The phase-Doppler data were used to begin an evaluation of commercial two-phase, three-dimensional, CFD code (FLUENT). Using a simplified representation of the spray based on velocity measurements 2 mm from the atomizer, it is shown that the model predicts drop trajectories, velocities, and volume fluxes reasonably well.
Parameterization of surface temperature retrieval for remote sensing experiments

Abstract A simple parameterization has been developed for determining the actual surface temperature from the effective brightness temperature measured radiometrically in the 11 μm window region. This algorithm allows the computation of atmospheric correction without performing detailed radiative transfer calculations. Correction due to atmospheric water vapor is represented in terms of the integrated water vapor burden. Correction due to variation of surface emittance is represented in terms of its deviation from unity. Parameteric representation has also been developed for simultaneous variation of both parameters. The parameterization is based on model calculations performed with a line-by-line radiative transfer program. Sensitivity of the retrieved surface temperature to uncertainties of water vapor burden and surface emittance have also been examined.
Polarization Smoothing on the National Ignition Facility

We have recently implemented polarization smoothing (PS) on one quad of the NIF laser. Specially cut KDP and DKDP crystals at 420 x 420 mm sizes were used to scramble the incident 351 nm laser polarization over the beam aperture. The intensity contrast deduced from the measured focal spot images for one of the NIF beams is in very good agreement with the expected contrast. KDP and DKDP crystals are known to produce considerable amount of transverse stimulated Raman scattering (SRS) when irradiated with large beams at {approx}1-2 GW/cm2. In order to measure the transverse SRS, we attached optical fibers on the side of one of the PS crystals. The KDP PS crystal showed > 1 J/cm2 side scattered SRS at irradiances of 1.2 GW/cm2. The DKDP (70% deuteration level) PS crystal showed significantly less SRS. Detailed analysis of the SRS scattering in the PS crystal is in progress.
Statistical properties of many particle eigenfunctions

Wavefunction correlations and density matrices for few or many particles are derived from the properties of semiclassical energy Green functions. Universal features of fixed energy (microcanonical) random wavefunction correlation functions appear which reflect the emergence of the canonical ensemble as N → ∞. This arises through a little known asymptotic limit of Bessel functions. Constraints due to symmetries, boundaries and collisions between particles can be included.
Raising the pKa limit of "soft" nucleophiles in palladium-catalyzed allylic substitutions: application of diarylmethane pronucleophiles.

The Tsuji–Trost allylic substitution reaction provides a useful and efficient approach to construct C–C bonds between sp3-hybridized carbons. The widely accepted paradigm for classifying the mode of attack of nucleophiles on palladium π-allyl intermediates in the Tsuji–Trost reaction is based on the pKa of the pronucleophile: (1) stabilized or “soft” carbon nucleophiles and heteroatom nucleophiles (e.g., pronucleophiles with pKa’s 25). One of the keys to the continuing development of allylic substitution processes remains broadening the scope of “soft” nucleophiles. Herein we report a general method for the room temperature Pd-catalyzed allylic substitution with diarylmethane derivatives (pKa’s up to 32). The synthetic significance of the method is that it provides a rapid access to products containing allylated diarylmethyl motifs. The method is general for a wide range of nucleophiles derived from diarylmethanes ...
Zeroing the Stellar Isochrone Scale: The Red Giant Clump Luminosity at Intermediate Metallicity

The color-magnitude diagrams of the open clusters NGC 2420 and NGC 2506 have been investigated as intermediate links between the solar neighborhood and the Magellanic Clouds. Two sets of theoretical isochrones that include convective overshoot are zeroed to the Sun at solar abundance and to the unevolved main-sequence dwarfs of the Hipparcos Catalogue at [Fe/H] = -0.4, requiring a differential of 0.4 mag between the unevolved main sequences at a given color. Adopting E(B-V) = 0.04 and [Fe/H] = -0.39 for NGC 2506 and E(B-V) = 0.04 and [Fe/H] = -0.29 for NGC 2420, the respective apparent moduli are (m-M) = 12.70 and 12.15, while the ages of both clusters are approximately 1.9 ± 0.2 Gyr or 2.2 ± 0.2 Gyr, depending on the choice of isochrones. From the composite giant branch of the two clusters, the mean clump magnitudes in V and I are found to be +0.47 and -0.48 (-0.17, +0.14), respectively. Applying a metallicity correction to the MI values, the cluster sample of Udalski leads to (m-M)0 = 18.42 (+0.17, -0.15) and 18.91 (+0.18, -0.16) for the LMC and SMC, respectively. A caveat to this discussion and potentially to the claim that clusters of the same abundance and age are identical is the observation that the V-I colors of the red giants in NGC 2506 are significantly redder at a given B-V than the giants in clusters of comparable age and/or metallicity. The distance scale above has been derived using the general cluster relation between B-V and V-I. If the CCD photometry in NGC 2506 is correctly tied to the standard system, MI for the clump will decrease and the distance moduli should increase by 0.1 mag.
Effect of Voltage Level on Power System Design for Solar Electric Propulsion Missions

SUMMARY AND CONCLUDING REMARKS A dedicated Fortran EPS performance code was used in concert with spreadsheet models to quantify the potential mass benefits of high voltage spacecraft power systems and a direct-drive architecture for a representative, Earth-orbiting solar electric propulsion mission. Results showed that spacecraft EPS mass decreased as PMAD voltage was increased over the range of 28-V to 300-V. The mass savings from higher voltage, lower current were achieved by the use of lighter power cabling and component down-sizing due to lower system losses. Results from a simplified model showed that 300-V PVA plasma electron current collection was less than 5% of the array operating current. Further mass benefits were afforded by the direct-drive architecture by eliminating the ARU, removing the PPU converter, reducing the PPU heat rejection radiator and down-sizing EPS components due to lower system losses. These mass benefits were achieved assuming either SOA or advanced EPS technologies. The impact of EPS and propulsion subsystem mass savings on the spacecraft ACS system was also calculated. Results showed that mass savings of a 120-V system over that of a 28-V system can save only a few percent in ACS propellant mass over the mission duration. Further increases in voltage and direct-drive implementation offer very little added ACS propellant mass savings. However, increasing system voltage from 120-V to 300-V reduced spacecraft dry mass to save 68-kg in spacecraft wet mass (out of an initial 1500-kg total wet mass) and implementing direct-drive saved an additional 104-kg of wet mass. These added mass savings were achieved by reduced xenon propellant and tankage mass in the spacecraft primary electric propulsion system.
Influence of composition and processing parameters on mechanical properties and erosion response of Ni–TiB2 coatings

AbstractSputtered Ni–TiB2 coatings have been shown to protect Ti–6Al–4V and Inconel 718 substrates from solid particle erosion. However, before new erosion resistant coatings can be efficiently designed, it is essential that the role of mechanical properties in determining erosion resistance be fully understood. In this investigation, nanoindentation techniques were used to quantify the effects of substrate preparation, coating composition, and sputtering process parameters on the elastic moduli and indentation hardness of thin coatings deposited on Ti–6Al–4V and Inconel 718 substrates. The influence of these parameters on coating adhesion was determined using a conventional scratch test. Elastic moduli, indentation hardnesses, and coating adhesion were correlated with erosion behaviour. The erosion resistance of the coatings that exhibited microscopic ductility is dependent on the nodule diameter and coating properties such as hardness, elastic modulus, and fracture toughness.MST/1697
Perpendicular bands of cyclopropane in the 3.5 μm region

Abstract The spectrum of the cyclopropane molecule was measured in the region 2898.5 to 3157.3 cm−1 with Doppler-limited resolution using a difference frequency laser spectrometer. Deconvolution was used to further enhance the effective resolution in the main part of the highly perturbed spectrum. The region below ∼3060 cm−1 contains perpendicular bands, including the ν8 fundamental of species E′ in close anharmonic resonance with the E′ component of the state ν7 + ν9 + ν14 and with other E′ states, and the ν2 + ν9 band which borrows its intensity from ν8 via Fermi resonance. The ν2 + ν9 E′ state is also perturbed by anharmonic interactions with additional E′ states. A comprehensive analysis of this complex system of perpendicular bands based on a Hamiltonian model of the main interactions yielded much improved spectroscopic constants for the ν8 fundamental, for the ν2 + ν9 combination, and for the newly observed ν7 + ν9 + ν14 state, as well as information on seven tentatively identified perturbing states.
Factoring formal power series over principal ideal domains

We provide an irreducibility test and factoring algorithm (with some qualificiations) for formal power series in the unique factorization domain R((X)), where R is any principal ideal domain. We also classify all integral domains arising as quotient rings of R((X)). Our main tool is a generalization of the p-adic Weierstrass preparation theorem to the context of complete filtered commutative rings.
Suppressing van der Waals driven rupture through shear

An ultra-thin viscous film on a substrate is susceptible to rupture instabilities driven by van der Waals attractions. When a unidirectional 'wind' shear τ is applied to the free surface, the rupture instability in two dimensions is suppressed when τ exceeds a critical value τ c and is replaced by a permanent finite-amplitude structure, an intermolecular-capillary wave, that travels at approximately the speed of the surface. For small amplitudes, the wave is governed by the Kuramoto-Sivashinsky equation. If three-dimensional disturbances are allowed, the shear is decoupled from disturbances perpendicular to the flow, and line rupture would occur. In this case, replacing the unidirectional shear with a shear whose direction rotates with angular speed, ω, suppresses the rupture if τ ≳ 2τ c . For the most dangerous wavenumber, τ c ≈ 10 -2 dyn cm -2 at ω ≈ 1 rad S -1 for a film with physical properties similar to water at a thickness of 100 nm.
Boxes go bananas: Encoding higher-order abstract syntax with parametric polymorphism*

Higher-order abstract syntax is a simple technique for implementing languages with functional programming. Object variables and binders are implemented by variables and binders in the host language. By using this technique, one can avoid implementing common and tricky routines dealing with variables, such as capture-avoiding substitution. However, despite the advantages this technique provides, it is not commonly used because it is difficult to write sound elimination forms (such as folds or catamorphisms) for higher-order abstract syntax. To fold over such a data type, one must either simultaneously define an inverse operation (which may not exist) or show that all functions embedded in the data type are parametric. In this paper, we show how first-class polymorphism can be used to guarantee the parametricity of functions embedded in higher-order abstract syntax. With this restriction, we implement a library of iteration operators over data structures containing functionals. From this implementation, we derive “fusion laws” that functional programmers may use to reason about the iteration operator. Finally, we show how this use of parametric polymorphism corresponds to the Schurmann, Despeyroux and Pfenning method of enforcing parametricity through modal types. We do so by using this library to give a sound and complete encoding of their calculus into System . This encoding can serve as a starting point for reasoning about higher-order structures in polymorphic languages.
Hypothesis Testing in Linear Regression when k/n is Large

Abstract This paper derives the asymptotic distribution of the F -test for the significance of linear regression coefficients as both the number of regressors, k , and the number of observations, n , increase together so that their ratio remains positive in the limit. The conventional critical values for this test statistic are too small, and the standard version of the F -test is invalid under this asymptotic theory. This paper provides a correction to the F statistic that gives correctly-sized tests both under this paper’s limit theory and also under conventional asymptotic theory that keeps k finite. This paper also presents simulations that indicate the new statistic can perform better in small samples than the conventional test. The statistic is then used to reexamine Olivei and Tenreyro’s results from [Olivei, G., Tenreyro, S., 2007. The timing of monetary policy shocks. The American Economic Review 97, 636–663] and Sala-i-Martin’s results from [Sala-i-Martin, X.X., 1997. I just ran two million regressions. The American Economic Review 87 (2), 178–183].
Minimum variance estimation of 3D face shape from multi-view

A minimum variance estimation framework for 3D face reconstruction from multiple views and a new 3D surface reconstruction algorithm based on deformable subdivision mesh is proposed in this paper. First, an efficient 2D-to-3D integrated face reconstruction approach is introduced to reconstruct a personalized 3D face model from a single frontal face image with minimum variance estimation. Then, a new deformable mesh based surface reconstruction algorithm is applied to the images from different views to get more observation of the 3D face, especially the depth information, which could not be obtained from a single image directly. Based on the result of the 3D surface reconstruction, we use the minimum variance estimation again to refine the estimation of the 3D face. We combine the texture from different views, and the result looks photorealistic.
Higher-dimensional voronoi diagrams in linear expected time

A general method is presented for determining the mathematical expectation of the combinatorial complexity and other properties of the Voronoi diagram ofn independent and identically distributed points. The method is applied to derive exact asymptotic bounds on the expected number of vertices of the Voronoi diagram of points chosen from the uniform distribution on the interior of ad-dimensional ball; it is shown that in this case, the complexity of the diagram is ?(n) for fixedd. An algorithm for constructing the Voronoid diagram is presented and analyzed. The algorithm is shown to require only ?(n) time on average for random points from ad-ball assuming a real-RAM model of computation with a constant-time floor function. This algorithm is asymptotically faster than any previously known and optimal in the average-case sense.
Detection of different kidney stone types: an ex vivo comparison of ultrashort echo time MRI to reference standard CT.

Abstract Background and purpose With the development of ultrashort echo time (UTE) sequences, it may now be possible to detect kidney stones by using magnetic resonance imaging (MRI). In this study, kidney stones of varying composition and sizes were imaged using both UTE MRI as well as the reference standard of computed tomography (CT), with different surrounding materials and scan setups. Methods One hundred and fourteen kidney stones were inserted into agarose and urine phantoms and imaged both on a dual-energy CT (DECT) scanner using a standard renal stone imaging protocol and on an MRI scanner using the UTE sequence with both head and body surface coils. A subset of the stones representing all composition types and sizes was then inserted into the collecting system of porcine kidneys and imaged in vitro with both CT and MRI. Results All of the stones were visible on both CT and MRI imaging. DECT was capable of differentiating between uric acid and nonuric acid stones. In MRI imaging, the choice of coil and large field of view (FOV) did not affect stone detection or image quality. The MRI images showed good visualization of the stones' shapes, and the stones' dimensions measured from MRI were in good agreement with the actual values ( R 2 =0.886, 0.895, and 0.81 in the agarose phantom, urine phantom, and pig kidneys, respectively). The measured T2 relaxation times ranged from 4.2 to 7.5ms, but did not show significant differences among different stone composition types. Conclusions UTE MRI compared favorably with the reference standard CT for imaging stones of different composition types and sizes using body surface coil and large FOV, which suggests potential usefulness of UTE MRI in imaging kidney stones in vivo.
Nonlinear diffraction tomography: The use of inverse scattering for imaging

Our recent inverse scattering work has been to derive inverse scattering theory and algorithms that can be used to process practical experimental data. The theory makes use of computation of the forward scattering solution. Therefore, an efficient forward solver is instrumental to the rapid solution of the inverse scattering problem. The advantage of the more sophisticated theory over a linear theory is that it accounts for multiple scattering effects within the scatterers which often give rise to distortions in an image. A new method to invert strong scatterers, such as metallic scatterers, is presented. © 1996 John Wiley & Sons, Inc.
Dynamic Processes Leading to Covalent Bond Formation for SN1 Reactions

The SN1 reaction mechanism is one of the most fundamental processes in organic chemistry. As such, it has been the subject of study for over 70 years with the purpose of seeking to understand the fundamental parameters that control reactivity. With recent advances in both electronic structure theory and condense-phase reaction dynamics theory as well as in experimental probes of these reactions on the femtosecond and picosecond time scale, we are beginning to gain new insights into the nature of these reactions.
A sea of biosynthesis: marine natural products meet the molecular age

The years 2000 through mid-2010 marked a transformational period in understanding of the biosynthesis of marine natural products. During this decade the field emerged from one largely dominated by chemical approaches to understanding biosynthetic pathways to one incorporating the full force of modern molecular biology and bioinformatics. Fusion of chemical and biological approaches yielded great advances in understanding the genetic and enzymatic basis for marine natural product biosynthesis. Progress was particularly pronounced for marine microbes, especially actinomycetes and cyanobacteria. During this single decade, both the first complete marine microbial natural product biosynthetic gene cluster sequence was released as well as the first entire genome sequence for a secondary metabolite-rich marine microbe. The decade also saw tremendous progress in recognizing the key role of marine microbial symbionts of invertebrates in natural product biosynthesis. Application of genetic and enzymatic knowledge led to genetic engineering of novel “unnatural” natural products during this time, as well as opportunities for discovery of novel natural products through genome mining. The current review highlights selected seminal studies from 2000 through to June 2010 that illustrate breakthroughs in understanding of marine natural product biosynthesis at the genetic, enzymatic, and small-molecule natural product levels. A total of 154 references are cited.
AN ANALYSIS AS TO THE CAUSAL RELATIONSHIP BETWEEN BIOETHANOL EXPANSION AND AGRICULTURAL CROP ACREAGE ALLOCATION IN THE UNITED STATES

This study analyzes the historical price response of individual crop acreage in order to determine the impacts of an expansionist policy in bioethanol production on the U.S. agricultural industry. In doing this, this study provides an economic foundation by using a traditional Rotterdam model to simulate a cropland demand system. Within the developed framework, this study estimates own and cross acreage elasticities and scale elasticities to show the impacts of acreage values on crop production and the relationship between total cropland and individual crop acreage. This study found that rice farming is most inelastic to own acreage value. Soybeans, hay, and wheat are shown to be good substitute crops for corn. Corn, soybeans, hay, wheat, cotton, barley, and rice are shown to have positive scale elasticity, while sorghum and oats are shown to have negative scale elasticities. The scale effects of corn, soybeans, hay, and wheat are relatively large, while those of cotton, sorghum, barley, rice, and oats are relatively small.
Quantum computing classical physics.

In the past decade, quantum algorithms have been found which outperform the best classical solutions known for certain classical problems as well as the best classical methods known for simulation of certain quantum systems. This suggests that they may also speed up the simulation of some classical systems. I describe one class of discrete quantum algorithms which do so – quantum lattice–gas automata – and show how to implement them efficiently on standard quantum computers.
Design and implementation of a single-chip 1-D median filter

The design and implementation of a VLSI chip for the one-dimensional median filtering operation is presented. The device is designed to operate on 8-bit sample sequences with a window size of five samples. Extensive pipelining and employment of systolic data-flow concepts at the bit level enable the chip to filter at rates up to ten megasamples per second. A configuration for using the chip for approximate two-dimensional median filtering operation is also presented.
Effect of Flue-Gas Impurities on the Process of Injection and Storage of CO2 in Depleted Gas Reservoirs

Our previous coreflood experiments—injecting pure CO2 into carbonate cores—showed that the process is a win-win technology, sequestrating CO2 while recovering a significant amount of hitherto unrecoverable natural gas that could help defray the cost of CO2 sequestration. In this paper, we report our findings on the effect of “impurities” in flue gas—N2, O2, H2O, SO2, NO2, and CO—on the displacement of natural gas during CO2 sequestration. Results show that injection of CO2 with approximately less than 1mole% impurities would result in practically the same volume of CO2 being sequestered as injecting pure CO2. This gas would have the advantage of being a cheaper separation process compared to pure CO2 as not all the impurities are removed. Although separation of CO2 out of flue gas is a costly process, it appears that this is necessary to maximize CO2 sequestration volume, reduce compression costs of N2 (approximately 80% of the stream), and improve sweep efficiency and gas recovery in the reservoir.
The Economics of Human Development and Social Mobility

This article distills and extends recent research on the economics of human development and social mobility. It summarizes the evidence from diverse literatures on the importance of early life conditions in shaping multiple life skills and the evidence on critical and sensitive investment periods for shaping different skills. It presents economic models that rationalize the evidence and unify the treatment effect and family influence literatures. The evidence on the empirical and policy importance of credit constraints in forming skills is examined. There is little support for the claim that untargeted income transfer policies to poor families significantly boost child outcomes. Mentoring, parenting, and attachment are essential features of successful families and interventions that shape skills at all stages of childhood. The next wave of family studies will better capture the active role of the emerging autonomous child in learning and responding to the actions of parents, mentors, and teachers.
In Treating Alcohol Use Disorders, Why Not Use Evidence-Based Treatment?

Alcohol use disorders are common and devastating diseases with a strong genetic component. Prevalence in the United States in adult men is about 12% (1). Besides the social and economic consequences of uncontrolled alcohol drinking, these disorders account for one in 10 deaths annually through accidents and secondary medical problems such as cirrhosis (2). Despite the importance of this category of disorders, less than a third of patients with alcohol use disorders receive any treatment, and fewer still receive evidence-based treatment. Early in the course of the disease, when treatment is most effective, symptoms are often ignored bymedical practitioners. The typical patient is only diagnosed late in the course of this progressive disease, when the symptoms become severe. Eventually a crisis develops that results in medical attention. If insurance coverage is available, the patient may be admitted to a residential program, and the patient receives medication to ease the symptoms of alcohol withdrawal. Even though Food and Drug Administration-approved medications with proven efficacy in reducing relapse are available, fewer than 10% of patients are treated with such medications (3). The typical residential program is built around “milieu” therapy and self-help groups. These treatment approaches lack efficacy, as demonstrated by controlled outcome studies. Some evidence-based psychotherapies, such as cognitive-behavioral therapy and motivational interviewing, are available (4), but none of them focus on the brain changes that produce the uncontrolled drinking. Instead, the typical treatment program stresses counseling, support, and group therapy. Patients are made comfortable with a healthy diet, educational lectures, and perhaps massage therapy and other spa-like features. Patients are advised to avoid people, places, or things that remind them of alcohol. By the end of 30 days, the patient may feel relatively well and optimistic, but the neuroplasticity, the changes in the brain that have become ingrained, have not been addressed. Thus, it is not surprising that repeated relapses to uncontrolled drinking are common.
International monetary coordination and the great deviation

Research in the early 1980s found that the gains from international coordination of monetary policy were quantitatively small compared to simply getting domestic policy right. That prediction turned out to be a pretty good description of monetary policy in the 1980s, 1990s, and until recently. Because this balanced international picture has largely disappeared, the 1980s view about monetary policy coordination needs to be reexamined. The source of the problem is not that the models or the theory are wrong. Rather there was a deviation from the rule-like monetary policies that worked well in the 1980s and 1990s, and this deviation helped break down the international monetary balance. There were similar deviations at many central banks, an apparent spillover culminating in a global great deviation. The purpose of this paper is to examine the possible causes and consequences of these spillovers, and to show that uncoordinated responses of central banks to the deviations can create an amplification mechanism, which might be overcome by some form of policy coordination.
Minimax-optimal Inference from Partial Rankings

This paper studies the problem of rank aggregation under the Plackett-Luce model. The goal is to infer a global ranking and related scores of the items, based on partial rankings provided by multiple users over multiple subsets of items. A question of particular interest is how to optimally assign items to users for ranking and how many item assignments are needed to achieve a target estimation error. Without any assumptions on how the items are assigned to users, we derive an oracle lower bound and the Cramer-Rao lower bound of the estimation error. We prove an upper bound on the estimation error achieved by the maximum likelihood estimator, and show that both the upper bound and the Cramer-Rao lower bound inversely depend on the spectral gap of the Laplacian of an appropriately defined comparison graph. Since random comparison graphs are known to have large spectral gaps, this suggests the use of random assignments when we have the control. Precisely, the matching oracle lower bound and the upper bound on the estimation error imply that the maximum likelihood estimator together with a random assignment is minimax-optimal up to a logarithmic factor. We further analyze a popular rank-breaking scheme that decompose partial rankings into pairwise comparisons. We show that even if one applies the mismatched maximum likelihood estimator that assumes independence (on pairwise comparisons that are now dependent due to rank-breaking), minimax optimal performance is still achieved up to a logarithmic factor.
TRUST AND POLITICAL ECONOMY Institutions and the Sources of Interfirm Cooperation

Cooperation between small firms in “industrial districts,” where the production process may be radically dis-integrated, poses an important challenge to current political science theories of trust and cooperation. In this article, the author suggests that the problems posed by these districts—the existence of apparently irrational forms of trust in the political economy and of high-trust forms of cooperation in societies with low levels of interpersonal trust—may be explained if one adopts a more sophisticated institutional approach. The author shows how institutions may affect trust between economic actors and thus cooperation in two case studies of industrial districts, mechanical engineering in Bologna, Italy, and Stuttgart, Germany, and shows that empirical evidence supports the hypothesis that trust may depend on institutions and vary with institutional context.
Chemical sensor networks for the aquatic environment

Monterey Bay Aquarium Research Institute, 7700 Sandholdt Road, Moss Landing, California 95039, School of Oceanography, University ofWashington, Seattle, Washington 98195-7940, Department of Marine, Earth and Atmospheric Sciences, North Carolina State University,Raleigh, North Carolina 27695Received July 14, 2006
An MRI Coil-Mounted Multi-Probe Robotic Positioner for Cryoablation

Cryoablation is a percutaneous procedure for treating solid tumors using needle-like instruments. This paper presents an interventional guidance device for faster and more accurate alignment and insertion of multiple probes during cryoablation performed in closed bore magnetic resonance (MR) imaging systems. The device is compact and is intended to be mounted onto a Siemens 110 mm MR loop coil. A cable-driven twodegrees-of-freedom spherical mechanism mimics the wrist motion as it orients the intervention probes about a remote center of motion located 15 mm above the skin. A carriage interfaces with the probes via a thumbscrew-fastened latch to passively release the probes from their tracks, enabling them to be inserted sequentially and freeing them to move with respiration. Small actuator modules containing piezoelectric encoder-based motors are designed to be snap-fit into the device for ease of replacement and sterilization. The robot MRI compatibility was validated with standard cryoablation imaging sequences in 3T MR environment, yielding a maximum of 4% signal to noise ratio during actuator motion. Bench-level device characterization demonstrated a maximum error of 0.78° in the carriage movement. Needle-tip placement experiments for multiple targets in gelatin were performed using our image-guided navigation software, measuring an average targeting error of 2.0 mm.
Microarrays, Empirical Bayes, and the Two-Groups Model

The classic frequentist theory of hypothesis testing developed by Neyman, Pearson, and Fisher has a claim to being the Twentieth Century’s most influential piece of applied mathematics. Something new is happening in the Twenty-First Century: high throughput devices, such as microarrays, routinely require simultaneous hypothesis tests for thousands of individual cases, not at all what the classical theory had in mind. In these situations empirical Bayes information begins to force itself upon frequentists and Bayesians alike. The two-groups model is a simple Bayesian construction that facilitates empirical Bayes analysis. This article concerns the interplay of Bayesian and frequentist ideas in the two-groups setting, with particular attention focussed on Benjamini and Hochberg’s False Discovery Rate method. Topics include the choice and meaning of the null hypothesis in large-scale testing situations, power considerations, the limitations of permutation methods, significance testing for groups of cases (such as pathways in microarray studies), correlation effects, multiple confidence intervals, and Bayesian competitors to the two-groups model.
Where Consumers Diverge from Others: Identity Signaling and Product Domains

We propose that consumers often make choices that diverge from those of others to ensure that they effectively communicate desired identities. Consistent with this identity‐signaling perspective, four studies illustrate that consumers are more likely to diverge from majorities, or members of other social groups, in product domains that are seen as symbolic of identity (e.g., music or hairstyles, rather than backpacks or stereos). In identity domains, participants avoided options preferred by majorities and abandoned preferences shared with majorities. The social group associated with a product influenced choice more in identity domains and when a given product was framed as identity relevant. People diverge, in part, to avoid communicating undesired identities.
How Does Peer Pressure Affect Educational Investments

When effort is observable to peers, students may try to avoid social penalties by conforming to prevailing norms. To test this hypothesis, we first consider a natural experiment that introduced a performance leaderboard into computer-based high school courses. The result was a 24 percent performance decline. The decline appears to be driven by a desire to avoid the leaderboard; top performing students prior to the change, those most at risk of appearing on the leaderboard, had a 40 percent performance decline, while poor performing students improved slightly. We next consider a field experiment that offered students complimentary access to an online SAT preparatory course. Sign-up forms differed randomly across students only in whether they said the decision would be kept private from classmates. In nonhonors classes, sign-up was 11 percentage points lower when decisions were public rather than private. Honors class sign-up was unaffected. For students taking honors and nonhonors classes, the response depended on which peers they were with at the time of the offer, and thus to whom their decision would be revealed. When offered the course in a nonhonors class (where peer sign-up rates are low), they were 15 percentage points less likely to sign up if the decision was public. But when offered the course in an honors class (where peer sign-up rates are high), they were 8 percentage points more likely to sign up if the decision was public. Thus, students are highly responsive to their peers are the prevailing norm when they make decisions.
An empirical study of the effect of knowledge integration on software development performance

Abstract Although the role of integrating application domain knowledge with technical knowledge is implicitly recognized in software engineering practice, no large scale study has attempted to validate this empirically in a field setting. In this paper, a large-scale empirical study of 232 software development projects in 232 software development organizations shows that higher integration of business application domain knowledge with technical knowledge during the software development process increases software development effectiveness, reduces defect density throughout the development trajectory, lowers warranty defects, and increases software development efficiency. The findings highlight the influence of knowledge integration on various dimensions of software development performance.
A Note on orientifolds and F - theory

Abstract An orientifold of Type-IIB theory on a K3 realized as a Z2 orbifold is constructed which corresponds to F-theory compactification on a Calabi-Yau orbifold with Hodge numbers (51, 3). The T-dual of this model is analogous to an orbifold with discrete torsion in that the action of orientation reversal has an additional phase on the twisted sectors, and both 9-branes and 5-branes carry orthogonal gauge groups. An orientifold of the Z3 orbifold and its relation to F-theory is briefly discussed.
Fluoro-Julia Olefination as a Mild, High-Yielding Route to α-Fluoro Acrylonitriles

Synthesis of a novel, stable reagent (1,3-benzothiazol-2-ylsulfonyl)fluoroacetonitrile from readily synthesized ethyl alpha-(1,3-benzothiazol-2-ylsulfanyl)-alpha-fluoroacetate is reported. Aldehydes undergo condensations with (1,3-benzothiazol-2-ylsulfonyl)fluoroacetonitrile in the presence of DBU leading to alpha-fluoro acrylonitriles in high yields and with good Z-stereoselectivity. Lowering of reaction temperature increases the Z selectivity.
Efficient analysis of complex diagrams using constraint-based parsing

This paper describes substantial advances in the analysis (parsing) of diagrams using constraint grammars. The addition of set types to the grammar and spatial indexing of the data make it possible to efficiently parse real diagrams of substantial complexity. The system is probably the first to demonstrate efficient diagram parsing using grammars that easily be retargeted to other domains. The work assumes that the diagrams are available as a flat collection of graphics primitives: lines, polygons, circles, Bezier curves and text. This is appropriate for future electronic documents or for vectorized diagrams converted from scanned images. The classes of diagrams that we have analyzed include x,y data graphs and genetic diagrams drawn from the biological literature, as well as finite state automata diagrams (states and arcs). As an example, parsing a four-part data graph composed of 133 primitives required 35 sec using Macintosh Common Lisp on a Macintosh Quadra 700.
Precision calibration of radio interferometers using redundant baselines

Growing interest in 21-cm tomography has led to the design and construction of broad-band radio interferometers with low noise, moderate angular resolution, high spectral resolution and wide fields of view. With characteristics somewhat different from traditional radio instruments, these interferometers may require new calibration techniques in order to reach their design sensitivities. Self-calibration or redundant calibration techniques that allow an instrument to be calibrated off complicated sky emission structures are ideal. In particular, the large number of redundant baselines possessed by these new instruments makes redundant calibration an especially attractive option. In this paper, we explore the errors and biases in existing redundant calibration schemes through simulations, and show how statistical biases can be eliminated. We also develop a general calibration formalism that includes both redundant baseline methods and basic point source calibration methods as special cases, and show how slight deviations from perfect redundancy and coplanarity can be taken into account.