cssi/SciSciGPT-SciSciNet huggingface dataset:
Inferring Latent Structure From Mixed Real and Categorical Relational Data

We consider analysis of relational data (a matrix), in which the rows correspond to subjects (e.g., people) and the columns correspond to attributes. The elements of the matrix may be a mix of real and categorical. Each subject and attribute is characterized by a latent binary feature vector, and an inferred matrix maps each row-column pair of binary feature vectors to an observed matrix element. The latent binary features of the rows are modeled via a multivariate Gaussian distribution with low-rank covariance matrix, and the Gaussian random variables are mapped to latent binary features via a probit link. The same type construction is applied jointly to the columns. The model infers latent, low-dimensional binary features associated with each row and each column, as well correlation structure between all rows and between all columns.
Dihydroxyacetone Variants in the Organocatalytic Construction of Carbohydrates: Mimicking Tagatose and Fuculose Aldolases

Dihydroxyacetone variants have been explored as donors in organocatalytic aldol reactions with various aldehyde and ketone acceptors. The protected form of dihydroxyacetone that was chosen for in-depth study was 2,2-dimethyl-1,3-dioxan-5-one, 1. Among the catalysts surveyed here, proline proved to be superior in terms of yield and stereoselectivities in the construction of various carbohydrate scaffolds. In a fashion analogous to aldolase enzymes, the de novo preparation of L-ribulose, L-lyxose, D-ribose, D-tagatose, 1-amino-1-deoxy-D-lyxitol, and other carbohydrates was accomplished via the use of 1 and proline. In reactions using 2,2-dimethyl-1,3-dioxan-5-one 1 as a donor, (S)-proline can be used as a functional mimic of tagatose aldolase, whereas (R)-proline can be regarded as an organocatalytic mimic of fuculose aldolase.
Synthesis and characterization of poly(pyridinium salt)s with organic counterion exhibiting both lyotropic liquid-crystalline and light-emitting properties

Abstract Two poly(pyridinium salt)s containing a bulky organic counterion such as 2-naphthalenesulfonate were synthesized by the ring-transmutation polymerization reaction of bis(pyrylium 2-naphthalenesulfonate) with the corresponding aromatic diamines on heating in dimethyl sulfoxide (DMSO) at 145–150 °C for 24 h, and characterized for their lyotropic liquid crystalline as well as fluorescence properties in both polar protic and aprotic solvents such as methanol and DMSO. Their polyelectrolyte behavior in DMSO was also determined by solution viscosity measurements.
Because I (Don't) Deserve It: How Relationship Reminders and Deservingness Influence Consumer Indulgence

Marketers regularly remind consumers of valued social relationships (e.g., close friends, family, romantic couples) to influence choice and consumption. However, the author's research reveals that such relationship reminders can backfire when consumers lack or no longer have these highlighted relationships. The author shows that reminding consumers of relationships they lack reduces their perceptions of deservingness and causes them to restrict indulgent consumption. Five studies establish the effect of relationship reminders on indulgence and provide support for the underlying process by both measuring and manipulating perceptions of deservingness.
Learning Nested Differences of Intersection-Closed Concept Classes

This paper introduces a new framework for constructing learning algorithms. Our methods involve master algorithms which use learning algorithms for intersection-closed concept classes as subroutines. For example, we give a master algorithm capable of learning any concept class whose members can be expressed as nested differences (for example, c1 – (c2 – (c3 – (c4 – c5)))) of concepts from an intersection-closed class. We show that our algorithms are optimal or nearly optimal with respect to several different criteria. These criteria include: the number of examples needed to produce a good hypothesis with high confidence, the worst case total number of mistakes made, and the expected number of mistakes made in the first t trials.
On Source Code Transformations for Steganographic Applications

The amount of publicly available source code on the Internet makes it attractive as a potential message carrier for steganographic applications. Unfortunately, it is often overlooked since embedding information in an undetectable way is challenging. We investigate term rewriting as a method for embedding messages into programs via transformations on source code. We elaborate on several possible transformation strategies and discuss how they might be applied in a steganographic setting. We continue with a discussion on (a) the implications and trade-offs of preserving semantic properties, (b) the relationship between messages and transformations, and (c) how to incorporate existing natural language processing techniques. The goal of this work is to elicit constructive feedback and present ideas that stimulate future work.
Reduced Bloch mode expansion for periodic media band structure calculations

Reduced Bloch mode expansion (RBME) is presented for fast periodic media band structure calculations. The expansion employs a natural basis composed of a selected reduced set of Bloch eigenfunctions. The reduced basis is selected within the irreducible Brillouin zone at high symmetry points determined by the medium’s crystal structure and group theory (and possibly at additional related points). At each of the reciprocal lattice selection points, a number of Bloch eigenfunctions are selected up to the frequency/energy range of interest for the band structure calculations. As it is common to initially discretize the periodic unit cell and solution field using some choice of basis, RBME is practically a secondary expansion that uses a selected set of Bloch eigenvectors. Such expansion therefore keeps, and builds on, any favourable attributes a primary expansion approach might exhibit. Being in line with the well-known concept of modal analysis, the proposed approach maintains accuracy while reducing the computation time by up to two orders of magnitudes or more depending on the size and extent of the calculations. Results are presented for phononic, photonic and electronic band structures.
Time irreversible copula-based Markov Models

Economic and financial time series frequently exhibit time irreversible dynamics. For instance, there is considerable evidence of asymmetric fluctuations in many macroeconomic and financial variables, and certain game theoretic models of price determination predict asymmetric cycles in price series. In this paper we make two primary contributions to the econometric literature on time reversibility. First, we propose a new test of time reversibility, applicable to stationary Markov chains. Compared to existing tests, our test has the advantage of being consistent against arbitrary violations of reversibility. Second, we explain how a circulation density function may be used to characterize the nature of time irreversibility when it is present. We propose a copula-based estimator of the circulation density, and verify that it is well behaved asymptotically under suitable regularity conditions. We illustrate the use of our time reversibility test and circulation density estimator by applying them to five years of Canadian gasoline price markup data.
MIMO design models and internal regulators for cyclicly switched parameter-adaptive control systems

In Pait and Morse (1994) the concept of "cyclic switching" was proposed as a means of dealing with the well-known stabilizability problem, which arises in adaptive controller synthesis because of the existence of points in parameter space where the design model upon which certainty equivalence control is based loses stabilizability. While the procedure outlined in the above paper is specific enough to enable one to construct cyclicly switched adaptive controllers for SISO process models, for the MIMO case two key issues are left unresolved. The objective of this paper is to address both of these issues, thereby extending excitation free, identifier-based adaptive control methods to minimum and nonminimum phase MIMO linear systems. >
Public Attitudes Toward Immigration

Immigrant populations in many developed democracies have grown rapidly, and so too has an extensive literature on natives' attitudes toward immigration. This research has developed from two theoretical foundations, one grounded in political economy, the other in political psychology. These two literatures have developed largely in isolation from one another, yet the conclusions that emerge from each are strikingly similar. Consistently, immigration attitudes show little evidence of being strongly correlated with personal economic circumstances. Instead, research finds that immigration attitudes are shaped by sociotropic concerns about its cultural impacts—and to a lesser extent its economic impacts—on the nation as a whole. This pattern of results has held up as scholars have increasingly turned to experimental tests, and it holds for the United States, Canada, and Western Europe. Still, more work is needed to strengthen the causal identification of sociotropic concerns and to isolate precisely how, when,...
The frequent paucity of trivial strings

A 1976 theorem of Chaitin can be used to show that arbitrarily dense sets of lengths n have a paucity of trivial strings (only a bounded number of strings of length n having trivially low plain Kolmogorov complexities). We use the probabilistic method to give a new proof of this fact. This proof is much simpler than previously published proofs, and it gives a tighter paucity bound.
Habits from Home, Lessons from School: Influences on Youth Civic Engagement

APSA is posting this article for public view on its website. APSA journals are fully accessible to APSA members and institutional subscribers. To view the table of contents or abstracts from this or any of APSA’s journals, please go to the website of our publisher Cambridge University Press (http://journals.cambridge.org). This article may only be used for personal, non-commercial, or limited classroom use. For permissions for all other uses of this article should be directed to Cambridge University Press at permissions@cup.org .
Audit committee quality, auditor independence, and internal control weaknesses

Abstract In this paper we investigate the relation between audit committee quality, auditor independence, and the disclosure of internal control weaknesses after the enactment of the Sarbanes-Oxley Act. We begin with a sample of firms with internal control weaknesses and, based on industry, size, and performance, match these firms to a sample of control firms without internal control weaknesses. Our conditional logit analyses indicate that a relation exists between audit committee quality, auditor independence, and internal control weaknesses. Firms are more likely to be identified with an internal control weakness, if their audit committees have less financial expertise or, more specifically, have less accounting financial expertise and non-accounting financial expertise. They are also more likely to be identified with an internal control weakness, if their auditors are more independent. In addition, firms with recent auditor changes are more likely to have internal control weaknesses.
Production and Marketing Characteristics of U.S. Pork Producers, 2006

A 2007 survey of US pork producers indicated that nearly two-thirds of US hogs are produced by less than 200 firms marketing 50,000 or more hogs per year. We estimate that 27 operations marketing at least 500,000 hogs a year sold 43% of US hogs in 2006. The next 164 operations marketing between 50 and 500 thousand hogs a year sold 21% of US hogs. Another 21% were marketed by 1,450 firms with annual sales of 10-50 thousand head. The remaining 15% of hogs were sold by firms marketing less than 10,000 hogs a year and this size category is losing market share as larger operations expand. Producers in all size categories are planning growth over the next three years. Production and marketing characteristics, cost of production, and plans for the future are reported by size category.
The Anatomy of Value and Growth Stock Returns

Average returns on value and growth portfolios are broken into dividends and three sources of capital gain: (1) growth in book equity, primarily from earnings retention, (2) convergence in price-to-book ratios (P/Bs) from mean reversion in profitability and expected returns, and (3) upward drift in P/B during 1927–2006. The capital gains of value stocks trace mostly to convergence: P/B rises as some value companies become more profitable and their stocks move to lower-expected-return groups. Growth in book equity is trivial to negative for value portfolios but is a large positive factor in the capital gains of growth stocks. For growth stocks, convergence is negative: P/B falls because growth companies do not always remain highly profitable with low expected stock returns. Relative to convergence, drift is a minor factor in average returns.
Genomic Comparisons of Humans and Chimpanzees

The genome consists of the entire DNA present in the nucleus of the fertilized embryo, which is then duplicated in every cell in the body. A draft sequence of the chimpanzee genome is now available, providing opportunities to better understand genetic contributions to human evolution, development, and disease. Sequence differences from the human genome were confirmed to be ∼1% in areas that can be precisely aligned, representing ∼35 million single base-pair differences. Some 45 million nucleotides of insertions and deletions unique to each lineage were also discovered, making the actual difference between the two genomes ∼4%. We discuss the opportunities and challenges that arise from this information and the need for comparison with additional species, as well as population genetic studies. Finally, we present a few examples of interesting findings resulting from genome-wide analyses, candidate gene studies, and combined approaches, emphasizing the pros and cons of each approach.
Numerical tests and properties of waves in radiating fluids

We discuss the properties of an analytical solution for waves in radiating fluids, with a view towards its implementation as a quantitative test of radiation hydrodynamics codes. A homogeneous radiating fluid in local thermodynamic equilibrium is periodically driven at the boundary of a one-dimensional domain, and the solution describes the propagation of the waves thus excited. Two modes are excited for a given driving frequency, generally referred to as a radiative acoustic wave and a radiative diffusion wave. While the analytical solution is well known, several features are highlighted here that require care during its numerical implementation. We compare the solution in a wide range of parameter space to a numerical integration with a Lagrangian radiation hydrodynamics code. Our most significant observation is that flux-limited diffusion does not preserve causality for waves on a homogeneous background.
Complements and substitutes in sequential auctions: the case of water auctions

We use data on sequential water auctions to estimate demand when units are com- plements or substitutes. A sequential English auction model determines the estimating structural equations. When units are complements, one bidder wins all units by paying a high price for the first unit, thus deterring others from bidding on subsequent units. When units are substitutes, different bidders win the units with positive probability, paying prices similar in magnitude, even when the same bidder wins all units. We re- cover individual demand consistent with this stark pattern of outcomes and confirm it is not collusive, but consistent with non-cooperative behavior. Demand estimates are biased if one ignores these features.
An integrated electric power supply chain and fuel market network framework: Theoretical modeling with empirical analysis for New England

In this article, we develop a novel electric power supply chain network model with fuel supply markets that captures both the economic network transactions in energy supply markets and the physical network transmission constraints in the electric power network. The theoretical derivation and analysis are done using the theory of variational inequalities. We then apply the model to a specific case, the New England electric power supply chain, consisting of six states, five fuel types, 82 power generators, with a total of 573 generating units, and 10 demand market regions. The empirical case study demonstrates that the regional electric power prices simulated by our model match the actual electricity prices in New England very well. We also compute the electric power prices and the spark spread, an important measure of the power plant profitability, under natural gas and oil price variations. The empirical examples illustrate that in New England, the market/grid-level fuel competition has become the major factor that affects the influence of the oil price on the natural gas price. Finally, we utilize the model to quantitatively investigate how changes in the demand for electricity influence the electric power and the fuel markets from a regional perspective. The theoretical model can be applied to other regions and multiple electricity markets under deregulation to quantify the interactions in electric power/energy supply chains and their effects on flows and prices. © 2009 Wiley Periodicals, Inc. Naval Research Logistics, 2009
Radiation heat transfer analysis of the monolith type solid oxide fuel cell

Abstract In this study, a modeling framework for heat and mass transport is established for a unit monolith type SOFC, with emphasis on quantifying the radiation heat transfer effects. The Schuster–Schwartzchild two-flux approximation is used for treating thermal radiation transport in the optically thin yttria-stabilized-zirconia (YSZ) electrolyte, and the Rosseland radiative thermal conductivity is used to account for radiation effects in the optically thick Ni–YSZ and LSM electrodes. The thermal radiation heat transfer is coupled to the overall energy conservation equations through the divergence of the local radiative flux. Commercially available FLUENT™ CFD software was used as a platform for the global thermal-fluid modeling of the SOFC and the radiation models were implemented through the user-defined functions. Results from sample calculations show significant changes in the operating temperatures and parameters of the SOFC with the inclusion of radiation effects.
Accounting for the business cycle: Nominal rigidities, factor heterogeneity, and Austrian capital theory

An Austrian interpretation of the New Keynesian small menu cost model of the business cycle is proposed. Austrian and New Keynesian business cycle theories share the feature that the cycle is generated by rigidities which prevent the economy from adapting instantaneously to changing conditions. Austrian business cycle theory is capital-based, focusing on credit expansion which artificially lowers interest rates and causes an investment boom and unsustainable business expansion. In contrast, the New Keynesian small menu cost model of the business cycle is based on nominal rigidities which prevent markets from clearing. Small menu costs introduce dichotomous behavior, where firms find it locally optimal to avoid instantaneous output price adjustments in the face of the cost, but this local optimum results in economy-wide output and employment fluctuations which are much greater in relative magnitude. The small menu cost model of the business cycle is extended and reinterpreted in light of Austrian business cycle theory with heterogeneous, multiply-specific capital, thus providing a rigorous formalization of the Austrian business cycle. The Austrian interpretation of this New Keynesian model fortuitously addresses several of its shortcomings.
Speech transformations based on a sinusoidal representation

In this paper a new speech analysis/synthesis technique is presented which provides the basis for a general class of speech transformations including time-scale modification, frequency scaling, and pitch modification. These modifications can be performed with a time-varying change, permitting continuous adjustment of a speaker's fundamental frequency and rate of articulation. The method is based on a sinusoidal representation of the speech production mechanism which has been shown to produce synthetic speech that preserves the wave-form shape and is perceptually indistinguishable from the original. Although the analysis/synthesis system was originally designed for single-speaker signals, it is also capable of recovering and modifying nonspeech signals such as music, multiple speakers, marine biologic sounds, and speakers in the presence of interferences such as noise and musical backgrounds.
Chiral lyotropic liquid crystals : TGB phases and helicoidal structures

The molecules in lyotropic membranes are typically aligned with the surface normal. When these molecules are chiral, there is a tendency for the molecular direction to twist. These competing effects can reach a compromise by producing helicoidal defects in the membranes. Unlike thermotropic smectics, the centers of these defects are hollow and thus their energy cost comes from the line energy of an exposed lamellar surface. We describe both the twist-grain-boundary phase of chiral lamellar phases as well as the isolated helicoidal defects.
Long-period, long-duration seismic events during hydraulic fracture stimulation of a shale gas reservoir

We report here a series of long-period and long-duration (LPLD) seismic events observed during hydraulic fracturing in a shale gas reservoir. These unusual events, 10–100 s in duration, are observed most clearly in the frequency band of 10–80 Hz and are remarkably similar in appearance to tectonic tremor sequences first observed in subduction zones. These complex but coherent wave trains have finite moveouts obtained from cross-correlation. The moveout direction of the events confirms that they originate in the reservoir from the area where the fracturing is going on. Clear P- and S-wave arrivals cannot be resolved within the LPLD episodes but, in some cases, small micro-earthquakes occur in the sequences. Whether these micro-earthquakes are causal or coincidental is not known. It has also been observed that in three contiguous frac-stages, all LPLD events appear to come from two distinct places along one of two hypothetical fracture planes. Interestingly, the stages which have the largest number of LPLD ...
Weight changes of male dairy calves following zeranol implants.

Abstract In a trial to determine the effect of zeranol implants on weight gains from birth to 180 days of age, 269 male Holstein calves were assigned randomly to one of three groups: a) 56 intact calves, b) 106 castrated calves implanted at birth and again at 90 days with 36mg zeranol, and c) 107 castrated controls. All calves were weighed at 0, 28, 56, 90, and 180 days of age. Zeranol-implanted steers averaged 9.2% greater average daily gain at 90 days and 9.5% greater at the end of the trial than control steers. Intact male calves' weight gains were intermediate between the two steer groups. There was no correlation between implant status, total protein of blood serum, mortality, birth weight, or parity of the dam. During the first 180 days of age, implanting Holstein calves with zeranol at birth and reimplanting at 90 days can return upwards of $14.89 per dollar invested.
Combined Optical and Neural Network Fingerprint Matching

This paper presents results on direct optical matching of inked and real-time fingerprint images. Direct optical correlations and hybrid optical neural network correlation are used in the matching system for inked fingerprints. Preliminary results on optical matching of real-time fingerprints use optical correlation. The test samples used in the inked image experiments are the fingerprint taken from NIST database SD-9. These images, in both binary and gray level forms, are stored in a VanderLugt correlator. Tests of typical cross correlations and auto correlation sensitivity for both binary and 8 bit gray images are presented. When global correlations are tested on a second inked image results are found to be strongly influenced by plastic distortion of the finger. When the correlations are used to generate features that are localized to parts of each fingerprint and combined using a neural network classification network and separate class-by-class matching networks, 84.3 percent matching accuracy is obtained on a test set of 100,000 image pairs. Initial results with real- time images suggest that the difficulties resulting from finger deformation can be avoided by combining many different distorted images when the hologram is constructed in the correlator. Testing this process will require analysis of 10-20 second sequences of digital video.© (1997) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Direct acceleration of an electron in infinite vacuum by a pulsed radially-polarized laser beam

We study the direct acceleration of a free electron in infinite vacuum along the axis of a pulsed radially-polarized laser beam. We find that net energy transfer from laser pulse to electron is maximized with the tightest focusing. We show that the net energy gain of an electron initially moving at a relativistic velocity may exceed more than half the theoretical limit of energy transfer, which is not possible with an initially stationary electron in the parameter space studied. We determine and analyze the power scaling of maximum energy gain, extending our study to include a relatively unexplored regime of low powers and revealing that substantial acceleration is already possible without the use of petawatt peak-power laser technology.
On unequal error protection LDPC codes based on plotkin-type constructions

We introduce a new family of unequal error protection (UEP) codes, based on low-density parity-check (LDPC) component codes and Plotkin-type constructions. The codes are decoded iteratively in multiple stages, and the order of decoding determines the level of error protection. The level of UEP among the code bits is also influenced by the choice of the LDPC component codes and by some new reliability features incorporated into the decoding process. The proposed scheme offers a very good tradeoff between code performance on one side and encoding/decoding and storage complexity on the other side. The novel approach to UEP also allows for finding simple approximations for the achievable degrees of UEP, which can be used to govern practical code design implementations
'Memories of paradise': legacies of socialist education in Mozambique

During the Cold War, state-led education exchange programmes between post-colonial states and the former German Democratic Republic (GDR) were common. The biggest such project, the School of Friendship (SdF), sent 899 Mozambican children for socialist-inspired schooling in the GDR. By the time they returned to Mozambique in 1988, the transition from socialist-revolutionary state to capitalist society was under way. This article discusses the legacies of socialist education, focusing on the lives of some of those who spent the decisive years of adolescence in the GDR. The narratives give insights into the contradictory social reality of this historical period, showing how the SdF equipped the participants with ‘modern’ virtues that became vital for their future lives, but which had also become largely obsolete by the time they returned to Mozambique. The SdF could thus be judged as a highly politicized programme where children were treated as pawns in a wider political game, while at the same time new horizons opened for its participants.
Toward an Ising Model of Cancer and Beyond

The holy grail of tumor modeling is to formulate theoretical and computational tools that can be utilized in the clinic to predict neoplastic progression and propose individualized optimal treatment strategies to control cancer growth. In order to develop such a predictive model, one must account for the numerous complex mechanisms involved in tumor growth. Here we review the research work that we have done toward the development of an ‘Ising model’ of cancer. The Ising model is an idealized statistical-mechanical model of ferromagnetism that is based on simple local-interaction rules, but nonetheless leads to basic insights and features of real magnets, such as phase transitions with a critical point. The review begins with a description of a minimalist four-dimensional (three dimensions in space and one in time) cellular automaton (CA) model of cancer in which cells transition between states (proliferative, hypoxic and necrotic) according to simple local rules and their present states, which can viewed as a stripped-down Ising model of cancer. This model is applied to study the growth of glioblastoma multiforme, the most malignant of brain cancers. This is followed by a discussion of the extension of the model to study the effect on the tumor dynamics and geometry of a mutated subpopulation. A discussion of how tumor growth is affected by chemotherapeutic treatment, including induced resistance, is then described. We then describe how to incorporate angiogenesis as well as the heterogeneous and confined environment in which a tumor grows in the CA model. The characterization of the level of organization of the invasive network around a solid tumor using spanning trees is subsequently discussed. Then, we describe open problems and future promising avenues for future research, including the need to develop better molecular-based models that incorporate the true heterogeneous environment over wide range of length and time scales (via imaging data), cell motility, oncogenes, tumor suppressor genes and cell–cell communication. A discussion about the need to bring to bear the powerful machinery of the theory of heterogeneous media to better understand the behavior of cancer in its microenvironment is presented. Finally, we propose the possibility of using optimization techniques, which have been used profitably to understand physical phenomena, in order to devise therapeutic (chemotherapy/radiation) strategies and to understand tumorigenesis itself.
Correlates of Heterosexual Anal Intercourse among Women in the 2006–2010 National Survey of Family Growth

Abstract Introduction Heterosexual anal intercourse (HAI) is common among U.S. women. Receptive anal intercourse is a known risk factor for HIV, yet there is a paucity of data on HAI frequency and distribution in the United States. Condom use is lower with HAI vs. vaginal intercourse, but little is known regarding of correlates of HAI with and without condoms. Aims The aims of this study were to describe recent (past 12 months) and lifetime HAI among sexually active reproductive‐aged U.S. women, and to characterize women who engage in HAI with and without condoms. Methods We analyzed a sample of 10,463 heterosexually active women aged 15–44 years for whom anal intercourse data were available in the 2006–2010 National Survey of Family Growth. Main Outcome Measures Weighted bivariate and multivariable analyses were used to determine HAI prevalence and correlates. Primary outcomes were lifetime HAI, recent (last 12 months) HAI, and condom use at last HAI. Results In our sample, 13.2% of women had engaged in recent HAI and 36.3% in lifetime HAI. Women of all racial and ethnic backgrounds and religions reported recent anal intercourse. Condom use was more common at last vaginal intercourse than at last anal intercourse (28% vs. 16.4%, P P P Conclusion Women of all ages and ethnicities engage in HAI, at rates higher than providers might realize. Condom use is significantly lower for HAI vs. vaginal intercourse, putting these women at risk for acquisition of sexually transmitted infections. Benson LS, Martins SL, and Whitaker AK. Correlates of heterosexual anal intercourse among women in the 2006–2010 National Survey of Family Growth. J Sex Med 2015;12:1746–1752.
Automated Extraction of the Cortical Sulci Based on a Supervised Learning Approach

It is important to detect and extract the major cortical sulci from brain images, but manually annotating these sulci is a time-consuming task and requires the labeler to follow complex protocols , . This paper proposes a learning-based algorithm for automated extraction of the major cortical sulci from magnetic resonance imaging (MRI) volumes and cortical surfaces. Unlike alternative methods for detecting the major cortical sulci, which use a small number of predefined rules based on properties of the cortical surface such as the mean curvature, our approach learns a discriminative model using the probabilistic boosting tree algorithm (PBT) . PBT is a supervised learning approach which selects and combines hundreds of features at different scales, such as curvatures, gradients and shape index. Our method can be applied to either MRI volumes or cortical surfaces. It first outputs a probability map which indicates how likely each voxel lies on a major sulcal curve. Next, it applies dynamic programming to extract the best curve based on the probability map and a shape prior. The algorithm has almost no parameters to tune for extracting different major sulci. It is very fast (it runs in under 1 min per sulcus including the time to compute the discriminative models) due to efficient implementation of the features (e.g., using the integral volume to rapidly compute the responses of 3-D Haar filters). Because the algorithm can be applied to MRI volumes directly, there is no need to perform preprocessing such as tissue segmentation or mapping to a canonical space. The learning aspect of our approach makes the system very flexible and general. For illustration, we use volumes of the right hemisphere with several major cortical sulci manually labeled. The algorithm is tested on two groups of data, including some brains from patients with Williams Syndrome, and the results are very encouraging
Urbanization and productivity : evidence from Turkish provinces over the period 1980-2000

Since the early 1980s, Turkey has been going through a rapid urbanization process at a pace beyond the World average. This paper aims at assessing the impact of this rapid urbanization process on the country's sector productivity. The authors built a database combining two-digit manufacturing data and some geographical, infrastructural, and socio-economic data collected at the provincial level by the Turkish State Institute of Statistics. The paper develops a parsimonious econometric relation linking sector productivity to accessibility, localization, and urbanization economies, proxying variables in the tradition of the New Economic Geography literature. The estimation results suggest that both localization and urbanization economies, as well as market accessibility, are productivity-enhancing factors in Turkey, although the causation link between productivity and these agglomeration measures is not clearly established. The sector-by-sector estimation confirms this result, although the localization economies effect is negative for the non-oil mineral sector, and the urbanization economies effect is weak for natural-resource-based sectors such as the wood and metal industry. Although the data cover the period up to 2000 and thus ignore the financial crisis that hit Turkey in 2001, the current structural transformation of the country away from the agricultural sector gives room to use the insights of these results as a preliminary step to understand the new challenges faced by the Turkish manufacturing sector. The results provide a discussion base to revisit the policy agenda on the improvement of the accessibility to markets, the improvement of the business environment to ease the creation and development of new firms, and a well-managed urbanization process to tap in the economic potential of cities.
Direct measurement of intervertebral disc maximum shear strain in six degrees of freedom: Motions that place disc tissue at risk of injury

Human intervertebral disc specimens were tested to determine the regions of largest maximum shear strain (MSS) experienced by disc tissues in each of three principal displacements and three rotations, and to identify the physiological rotations and displacements that may place the disc at greatest risk for large tissue strains and injury. Tearing of disc annulus may be initiated by large interlamellar shear strains. Nine human lumbar discs were tagged with radiographic markers on the endplates, disc periphery and with a grid of wires in the mid-transverse plane and subjected to each of the six principal displacements and rotations. Stereo-radiographs were taken in each position and digitized for reconstruction of the three-dimensional position of each marker. Maximum tissue shear strains were calculated from relative marker displacements and normalized by the input displacement or rotation. Lateral shear, compression, and lateral bending were the motions that produced the mean (95% confidence interval) largest mean MSS of 9.6 (0.7)%/mm, 9.0 (0.5)%/mm, and 5.8 (1.6)%/ degrees , respectively, and which occurred in the posterior, posterolateral and lateral peripheral regions of the disc. After taking into account the reported maximum physiological range of motion for each degree of freedom, motions producing the highest physiological MSS were lateral bending (57.8 (16.2)%) and flexion (38.3 (3.3)%), followed by lateral shear (14.4 (1.1)%) and compression (12.6 (0.7)%).
Tightness for Maxima of Generalized Branching Random Walks

We study generalized branching random walks on the real line R that allow time dependence and local dependence between siblings. Specifically, starting from one particle at time 0, the system evolves such that each particle lives for one unit amount of time, gives birth independently to a random number of offspring according to some branching law, and dies. The offspring from a single particle are assumed to move to new locations on R according to some joint displacement distribution; the branching laws and displacement distributions depend on time. At time n, F n (·) is used to denote the distribution function of the position of the rightmost particle in generation n. Under appropriate tail assumptions on the branching laws and offspring displacement distributions, we prove that F n (· - Med(F n )) is tight in n, where Med(F n ) is the median of F n . The main part of the argument is to demonstrate the exponential decay of the right tail 1 - F n (· - Med(F n )).
Effects of fuel-air unmixedness on NO(x) emissions

Unmixedness effects of lean fuel-air mixtures on emissions of nitrogen oxides (NOV) are experimentally studied. The objective is to study the relative influence of temporal fuel concentration fluctuations and spatial nonuniformities of mean concentration profiles on NO V emissions from lean premixed combustion. The NO2 laserinduced fluorescence (LIF) technique is used to quantify Unmixedness levels at the flameholder. Unmixedness data are related to NOr emissions measurements from downstream of the flames. The results show that temporal unmixedness contributes significantly to higher NOX emissions. It is not sufficient to eliminate only spatial nonuniformities of mean concentration in order to minimize NO_V emissions from lean premixed combustion. Nomenclature c = volumetric fuel concentration c' = rms fluctuation component of c c - time-mean fuel concentration Dc = combustor diameter Z)cf = coflow diameter Dj = jet diameter Recf = coflow Reynolds number Rej - jet Reynolds number U = unmixedness parameter Xj - distance from jet to flameholder z - vertical coordinate; origin at combustor centerline = fuel-air equivalence ratio
The Kondo model with a bulk mass term

We introduce two massive versions of the anisotropic spin 12 Kondo model and discuss their integrability. The two models have the same bulk sine-Gordon interactions, but differ in their boundary interactions. At the Toulouse free fermion point each of the models can be understood as two decoupled Ising models in boundary magnetic fields. Reflection S-matrices away from the free fermion point are conjectured.
The remarkable stability of probable black hole low‐mass X‐ray binaries in nearby galaxies

The most luminous X-ray sources in nearby elliptical galaxies are likely black hole lowmass X-ray binaries (BHLMXBs). In the Milky Way, such systems are always transient, and with the exception of GRS 1915+105 have burst durations on the order of weeks or months. However, the low duty cycle of short-duration outburst BHLMXBs makes it improbable that any one source would be caught in an outburst during a single snapshot observation. Longduration outburst BHLMXBs, although much rarer, would be detectable in a series of snapshot observations separated by several years. Our analysis of multi-epoch Chandra observations of the giant elliptical galaxies NGC 1399 and M87 separated by 3.3 and 5.3 yr, respectively, finds that all 37 luminous (>8 × 10 38 erg s −1 ) X-ray sources that were present in the first epoch observations were still in outburst in all of the following observations. Many of these probable long-duration outburst BHLMXBs reside within globular clusters of the galaxies. Conversely, no definitive short-duration outburst BHLMXBs were detected in any of the observations. This places an upper limit on the ratio of short-to-long-duration outbursters that is slightly lower, but consistent with what is seen in the Milky Way. The fact that none of the luminous sources turned off between the first and last epochs places a 95 per cent lower limit of 50 yr on the mean burst duration of the long-duration outburst sources. The most likely scenario for the origin of these sources is that they are long-period (>30 d) black hole binaries with a red giant donor, much like GRS 1915+105. However, unlike GRS 1915+105, most of the sources show only modest variability from epoch to epoch.
Vacuum bubbles in the presence of a relativistic fluid

First order phase transitions are characterized by the nucleation and evolution of bubbles. The dynamics of cosmological vacuum bubbles, where the order parameter is independent of other degrees of freedom, are well known; more realistic phase transitions in which the order parameter interacts with the other constituents of the Universe is in its infancy. Here we present high-resolution lattice simulations that explore the dynamics of bubble evolution in which the order parameter is coupled to a relativistic fluid. We use a generic, toy potential, that can mimic physics from the GUT scale to the electroweak scale.
Regiodivergent Addition of Phenols to Allylic Oxides: Control of 1,2- and 1,4-Additions for Cyclitol Synthesis†

Control of 1,2- and 1,4-addition of substituted phenols to allylic oxides is achieved by intercepting palladium π-allyl complexes. The interconversion of palladium complexes results in the total synthesis of MK 7607, cyathiformine B type, streptol, and a new cyclitol.
Cold fronts by merging of shocks

Cold fronts (CFs) are found in most galaxy clusters, as well as in some galaxies and groups of galaxies. We propose that some CFs are relics of merging between two shocks propagating in the same direction. Such shock mergers typically result in a quasi-spherical, factor � 1:4− 2:7 discontinuity in density and in temperature. These CFs may be found as far out as the virial shock, unlike what is expected in other CF formation models. As a demonstration of this effect, we use one dimensional simulations of clusters and show that shock induced cold fronts form when perturbations such as explosions or mergers occur near the cluster’s centre. Perturbations at a cluster’s core induce periodic merging between the virial shock and outgoing secondary shocks. These collisions yield a distinctive, concentric, geometric sequence of CFs which trace the expansion of the virial shock.
A simple mass storage system for the SRB data grid

The functionality that is provided by Mass Storage Systems can be implemented using data grid technology. Data grids already provide many of the required features, including a logical name space and a storage repository abstraction. We demonstrate how management of tape resources can be integrated into data grids. The resulting infrastructure has the ability to manage archival storage of digital entities on tape or other media, while maintaining copies on distributed, remote disk caches that can be accessed through advanced discovery mechanisms. Data grids provide additional levels of data management including the ability to aggregate data into containers before storage on tape, and the ability to migrate collections across a hierarchy of storage devices.
The target mechanism: Will it propagate or stifle a stage III crisis?

Abstract Skeptics have long believed that the EMU faces a dangerous period in Stage III when the “legacy” currencies will still be in circulation. The issue of whether the EMU could collapse arises from whether a country can extricate itself from the treaty. I will look briefly at some of the legal questions concerning a breakup of the union, specifically focusing on some costs that would materialize. This paper mainly will consider the technical mechanism whereby a crisis will be propagated through the financial system of the union, if a crisis does arise. The crisis may emerge as a straight banking crisis and not as an attack on the permanence of the EMU at all. It may reflect a disbelief in the permanence of the union; even if this belief is erroneous, it is worth examining how the funds will flow across borders and how the system will be defended. Finally, there may be a crisis that is preliminary to the collapse of the union itself. I include some earlier work on the propagation of a crisis in Stage III and examine issues of timing and dynamics of an attack.
Improving Social Well- Being Through New Democratic Institutions

We evaluate the role of a new type of democratic institution, participatory budgeting (PB), for improving citizens' well-being. Participatory institutions are said to enhance governance, citizens' empowerment, and the quality of democracy, creating a virtuous cycle to improve the poor's well-being. Drawing from an original database of Brazil's largest cities over the last 20 years, we assess whether adopting PB programs influences several indicators of well-being inputs, processes, and outcomes. We find PB programs are strongly associated with increases in health care spending, increases in civil society organizations, and decreases in infant mortality rates. This connection strengthens dramatically as PB programs remain in place over longer time frames. Furthermore, PB's connection to well-being strengthens in the hand of mayors from the nationally powerful, ideologically and electorally motivated Workers' Party. Our argument directly addresses debates on democracy and well-being and has powerful implications for participation, governance, and economic development.
Periods in partial words: An algorithm

Partial words are finite sequences over a finite alphabet that may contain some holes. A variant of the celebrated Fine-Wilf theorem shows the existence of a bound L=L(h,p,q) such that if a partial word of length at least L with h holes has periods p and q, then it also has period gcd(p,q). In this paper, we associate a graph with each p- and q-periodic word, and study two types of vertex connectivity on such a graph: modified degree connectivity and r-set connectivity where r=qmodp. As a result, we give an algorithm for computing L(h,p,q) in the general case and show how to use it to derive the closed formulas.