cssi/SciSciGPT-SciSciNet huggingface dataset:
Multiple Error-Correcting WOM-Codes

A Write Once Memory (WOM) is a storage medium with binary memory elements, called cells, that can change from the zero state to the one state only once. Examples of WOMs include punch cards and optical disks. WOM-codes, introduced by Rivest and Shamir, permit the reuse of a WOM by taking into account the location of cells that have already been changed to the one state. The objective in designing WOM-codes is to use the fewest number of cells to store a specified number of information bits in each of several reuses of the memory. An [n,k,t] WOM-code C is a coding scheme for storing k information bits in n cells t times. At each write, the state of each cell can be changed, provided that the cell is changed from the zero state to the one state. The rate of C, defined by R(C) = kt/n, indicates the total amount of information that is possible to store in a cell in t writes. Two WOM-code constructions correcting a single cell-error were presented by Zemor and Cohen. In this paper, we present another construction of a single-error-correcting WOM-code with a better rate. Our construction can be adapted also for single-error-detection, double-error-correction, and triple-error-correction. For the last case, we use triple-error-correcting BCH-like codes, which were presented by Kasami and more recently described again by Bracken and Helleseth. Finally, we show two constructions that can be combined for the correction of an arbitrary number of errors.
An attention-based view of real options reasoning

Real options reasoning assumes timely and effective managerial decision making yet does not address managers' ability to provide it. An attention-based view describes managerial behavior under varying structural conditions. I examine real options reasoning from an attention-based view. I develop several testable propositions regarding the effects of a firm's particular concrete and contextual attention structures on the ways in which its managers notice, champion, acquire, maintain, exercise, and abandon the various real options within its portfolio. I conclude with implications for future empirical research on real options reasoning.
Endogenous Skill Acquisition and Export Manufacturing in Mexico

Studies based on …rm-level data …nd that both exporting …rms and multinational corporations pay higher wages, for a given skill level. However, the literature overlooks the fact that export manufacturing …rms may also change the educational choices of the workforce. This paper con…rms that for Mexico over the period 1986-2000, the export sector pays higher wages than other sectors, but school drop out increases with the arrival of new export jobs. The workers induced to enter export manufacturing eventually earn less than they would have earned had
Drift Estimation of Generalized Security Price Processes from High Frequency Derivative Prices

This paper presents a framework for using high frequency derivative prices to estimate the drift of generalized security price processes. This work may be seen more generally as a quasi-likelihood approach to estimating continuous-time parameters of derivative pricing models using discrete option data. We develop a generalized derivative-based estimator for the drift where the underlying security price process follows any arbitrary state-time separable diffusion process (including arithmetic and geometric Brownian motion as special cases). The framework provides a method to measure premia in derivative prices, test for risk-neutral pricing and leads to a new empirical approach to pricing derivative contingent claims. A sufficient condition for the asymptotic consistency of the generalized estimator is also obtained. A study based on generating the S&P500 index and calls shows that the estimator can correctly estimate the drift parameter.
Zero-shot recognition with unreliable attributes

In principle, zero-shot learning makes it possible to train a recognition model simply by specifying the category's attributes. For example, with classifiers for generic attributes like striped and four-legged, one can construct a classifier for the zebra category by enumerating which properties it possesses—even without providing zebra training images. In practice, however, the standard zero-shot paradigm suffers because attribute predictions in novel images are hard to get right. We propose a novel random forest approach to train zero-shot models that explicitly accounts for the unreliability of attribute predictions. By leveraging statistics about each attribute's error tendencies, our method obtains more robust discriminative models for the unseen classes. We further devise extensions to handle the few-shot scenario and unreliable attribute descriptions. On three datasets, we demonstrate the benefit for visual category learning with zero or few training examples, a critical domain for rare categories or categories defined on the fly.
Discovering urban spatial-temporal structure from human activity patterns

Urban geographers, planners, and economists have long been studying urban spatial structure to understand the development of cities. Statistical and data mining techniques, as proposed in this paper, go a long way in improving our knowledge about human activities extracted from travel surveys. As of today, most urban simulators have not yet incorporated the various types of individuals by their daily activities. In this work, we detect clusters of individuals by daily activity patterns, integrated with their usage of space and time, and show that daily routines can be highly predictable, with clear differences depending on the group, e.g. students vs. part time workers. This analysis presents the basis to capture collective activities at large scales and expand our perception of urban structure from the spatial dimension to spatial-temporal dimension. It will be helpful for planers to understand how individuals utilize time and interact with urban space in metropolitan areas and crucial for the design of sustainable cities in the future.
Hybrid Bayesian networks with linear deterministic variables

When a hybrid Bayesian network has conditionally deterministic variables with continuous parents, the joint density function for the continuous variables does not exist. Conditional linear Gaussian distributions can handle such cases when the continuous variables have a multi-variate normal distribution and the discrete variables do not have continuous parents. In this paper, operations required for performing inference with conditionally deterministic variables in hybrid Bayesian networks are developed. These methods allow inference in networks with deterministic variables where continuous variables may be non-Gaussian, and their density functions can be approximated by mixtures of truncated exponentials. There are no constraints on the placement of continuous and discrete nodes in the network.
Regularity theory for fully nonlinear integro‐differential equations

We consider nonlinear integro-differential equations, like the ones that arise from stochastic control problems with purely jump Levy processes. We obtain a nonlocal version of the ABP estimate, Harnack inequality, and interior C 1,� regularity for general fully nonlinear integro- differential equations. Our estimates remain uniform as the degree of the equation approaches two, so they can be seen as a natural extension of the regularity theory for elliptic partial differential equations.
Çatalhöyük in the Context of the Middle Eastern Neolithic

This review aims to show how the new results from Catalhoyuk in central Turkey contribute to wider theories about the Neolithic in Anatolia and the Middle East. I argue that many of the themes found in symbolism and daily practice at Catalhoyuk occur very early in the processes of village formation and the domestication of plants and animals throughout the region. These themes include a social focus on memory construction; a symbolic focus on wild animals, violence, and death; and a central dominant role for humans in relation to the animal world. These themes occur early enough throughout the region that we can claim they are integral to the development of settled life and the domestication of plants and animals. Particularly the focus on time depth in house sequences may have been part of the suite of conditions, along with environmental and ecological factors, that “selected for” sedentism and domestication.
Heating and Ignition of Metallic Particles by a CO2 Laser

This paper presents an experimental technique and respective heat transfer model for studying ignition of micron-sized metallic particles at varied heating rates in the range of 10 6 K/s. The experimental setup uses a CO 2 laser as a heating source. The interaction of the laser beam with particles is particle size dependent and a narrow range of particle sizes (around 3.37 μm) is heated most effectively. Therefore, the heat transfer model needs to be analyzed only for the particles with this specific size, which greatly simplifies the interpretation of experiments. The powder is aerosolized inside a plate capacitor by charging particles contacting the capacitor's electrodes. A thin, laminar aerosol jet is carried out by an oxidizing gas through a small opening in the top electrode and is fed into a laser beam. The velocities of particles in the jet are in the range of 0.1-3 m/s. For each selected jet velocity, the laser power is increased until the particles are observed to ignite. The ignition is detected optically using a digital camera and a photomultiplier. The ignition thresholds for spherical aluminum powder were measured at three different particle jet velocities resulting in three different heating rates. The experimental data for aluminum, for which the ignition kinetics parameters are known, were acquired at a specific heating rate and used to calibrate the detailed heat transfer model. The experiments with different heating rates were performed to validate the model. The developed experimental technique and the heat transfer model can now be used to determine the ignition kinetics of different metallic powders in various gas environments.
Emittance growth in a storage ring due to ground motion

It is pointed out that, for a synchrotron light source designed for a small natural emittance, ground motion could lead to a nonnegligible growth in emittance. When the ground motion is of the plane-wave type, this dynamical process can be studied analytically by employing a method that combines the previously developed transfer function technique with a normal mode analysis that takes into account the magnification of the motion due to magnet supports. The explicit relationship between the amplitudes of the ground vibration and the emittance growth as a function of the vibration frequency is presented. Numerical examples are included. It is shown that the effects of low-frequency vibrations (below 20 Hz) can be alleviated with feedback systems using steering magnets. Higher-frequency vibrations that result in unacceptable emittance growth cannot be corrected in this manner and must be eliminated at their source or otherwise controlled. >
Synthesis of Cis- and Trans-1-methylcyclohexane-1,4-diols and Their 4-Hemisuccinate Esters

Abstract Stereoselective syntheses of the previously uncharacterized cis- and trans-1-methylcyclohexane-1,4-diols and their conversion to 4-hemisuccinate esters are described.
Random Tensors and Planted Cliques

The r -parity tensor of a graph is a generalization of the adjacency matrix, where the tensor's entries denote the parity of the number of edges in subgraphs induced by r distinct vertices. For r = 2, it is the adjacency matrix with 1's for edges and *** 1's for nonedges. It is well-known that the 2-norm of the adjacency matrix of a random graph is $O(\sqrt{n})$. Here we show that the 2-norm of the r -parity tensor is at most $f(r)\sqrt{n}\log^{O(r)}n$, answering a question of Frieze and Kannan [1] who proved this for r = 3. As a consequence, we get a tight connection between the planted clique problem and the problem of finding a vector that approximates the 2-norm of the r -parity tensor of a random graph. Our proof method is based on an inductive application of concentration of measure.
The reaction of disilenes with P4 and As4

Abstract Tetraaryldisilenes 1a-c react with white phosphorus to give bicyclo[1.1.0] butane compounds 2a-c . The more hindered disilene E-1,2-dimesityl-1,2-di-tert-butyldisilene ( 1e ) reacts slowly with P4 at 40 °C to give mainly a mixture of two diastereomeric intermediates with formula Mes4(tert-Bu) 4 Si 4 P 4 , 3 and 3 ′, with small amounts of the exo-endo ( 2e ) and -exo (2e′) isomers of the bicyclo[1.1.0]butane structure. At higher temperatures the intermediates are transformed into 2e and 2e′ and simultaneously rearrangement of 2e to 2e′ takes place. The X-ray crystal structure of the adduct 2e ′-[W(CO 5 ) 2 was determined: it crystallized in the C2 / c space group, Z =4, with cell dimensions a =18.616(4), b =13.872(3), c =16.815(3) A and β=109.95°. Based on 2D NMR studies, structures are proposed for intermediates 3 and 3 ′. Reaction of disilene 1a with As 4 leads to a compound Mes 8 Si 4 As 4 with a tricyclic structure 7 , as well as a bicyclo[1.1.0]butane, 6 .
Optically-active dihydropyridines via lipase-catalyzed enantioselective hydrolysis

Abstract Several prochiral esters of 1,4-dihydropyridines were enantioselectively hydrolyzed by Pseudomonas lipases (AK, P-30, and K-10) and Candida cylindracea lipase (OF-360). The stereochemical preferences of the lipases P-30 and K-10 were found to be always 4-Pro R and that of OF-360 to be 4-Pro S. In contrast, the prochiral preference of the lipase AK varied depending on the substitution on the dihydropyridine ring. The N-methoxymethyl derivatives afforded the 4S isomers (95% ee) whereas the N-unsubstituted compounds yielded the 4R isomers (50–70% ee).
A novel stereoselective route to some uncommon amino acids

Abstract An efficient synthesis of a d - erythro -β-methylaspartic acid analog was achieved in six steps from commercially available material. Evans' aldol reactions were utilized followed by Weinreb amide formation and Mitsunobu inversion to achieve the necessary stereochemistry of the amino acid target. The technique was applied to the synthesis of an aspartic acid analog as well as a diaminobutyric acid analog.
The effect of identifying vulnerabilities and patching software on the utility of network intrusion detection

Vulnerability scanning and installing software patches for known vulnerabilities greatly affects the utility of network-based intrusion detection systems that use signatures to detect system compromises. A detailed timeline analysis of important remote-to-local vulnerabilities demonstrates (1) Vulnerabilities in widely-used server software are discovered infrequently (at most 6 times a year) and (2) Software patches to prevent vulnerabilities from being exploited are available before or simultaneously with signatures. Signature-based intrusion detection systems will thus never detect successful system compromises on small secure sites when patches are installed as soon as they are available. Network intrusion detection systems may detect successful system compromises on large sites where it is impractical to eliminate all known vulnerabilities. On such sites, information from vulnerability scanning can be used to prioritize the large numbers of extraneous alerts caused by failed attacks and normal background traffic. On one class B network with roughly 10 web servers, this approach successfully filtered out 95% of all remote-to-local alerts.
New approaches to studies of exotic nuclei

Abstract New generations of 4π gamma-ray detectors, recoil mass spectrometers (RMS), and radioactive beam accelerators will open up many new areas of research, including presently inaccessible in-beam and radioactive decay studies of exotic nuclei still farther off stability. The new generation RMS and radioactive beam developments at the Holifield Heavy Ion Research Facility are presented. Current research and future prospects to probe the N = Z line up to 100Sn are described. Superdeformation in A = 70 to 190 nuclei is described in terms of its underlying physics of reinforcing proton and neutron shell gaps which lead to new superdeformed, doubly-magic nuclei. Recent results provide new insights into the coexistence of multiple nuclear shapes near the ground states.
Continuous-time adaptive control of systems with unknown backlash

This paper addresses one of the nondifferentiable nonlinearities which appear very often in industrial control applications: backlash. The authors first present a right inverse of backlash and then give one of its possible implementations. Characteristics like backlash are seldom known, so an adaptive version of the authors' backlash inverse is more suitable for applications. The authors develop an adaptive backlash inverse scheme and apply it to feedback control of a known linear plant with an unknown backlash at its input. The authors use simulation results to illustrate achieved performance improvements. >
Symbolic Simulation, Model Checking and Abstraction with Partially Ordered Boolean Functional Vectors

Boolean Functional Vectors (BFVs) are a symbolic representation for sets of bit-vectors that can be exponentially more compact than the corresponding characteristic functions with BDDs. Additionally, BFVs are the natural representation of bit-vector sets for Symbolic Simulation. Recently, we developed set manipulation algorithms for canonical BFVs by interpreting them as totally ordered selections. In this paper we generalize BFVs by defining them with respect to a partial order. We show that partially ordered BFVs can serve as abstractions for bit-vector sets and can be used to compute over-approximations in reachability analysis. In the special case when the underlying graph of the partial order is a forest, we can efficiently compute an abstract interpretation in a symbolic simulation framework. We present circuit examples where we leverage the exponential gap in the representations and inherent structure in the state-space to demonstrate the usefulness of Partially Ordered Boolean Functional Vectors.
Superhumps in the helium dwarf nova KL Draconis

We report on the discovery of a 25.5-min superhump period for the suspected helium dwarf nova system KL Draconis in a high state. The presence of superhumps combined with the previously observed helium spectrum and large-amplitude photometric variations confirm that KL Dra is an AM CVn system similar to CR Bootis, V803 Cen and CP Eridani. We also find a low-state photometric period at 25.0 min that we suggest may be the orbital period. With this assumption, we estimate q=0.075, M1=0.76 M⊙ and M2=0.057 M⊙.
Growth-Indexed Bonds in Emerging Markets: a Quantitative Approach

In the aftermath of sovereign defaults and financial crises in the 1990s, there have been calls for the widespread use by sovereigns of equity-like financial instruments, in particular, of GDP-indexed bonds. This paper calibrates a general equilibrium model with endogenous default to a typical emerging market economy and evaluates whether the existence of GDP-indexed bond, as proposed in the literature, is quantitatively important in what concerns spreads, debt to GDP ratios, and the likelihood of default. For the calibrated economy with shocks to the trend, the existence of GDP-indexed bonds allows the borrower to increase the debt to GDP ratio, while substantially reducing spreads because of the unwillingness of the borrower to default for debt levels supplied by the market. These effects are stronger the larger the persistence and the volatility of shocks to trend.
Decentralization and Fiscal Management in Colombia

Colombia's political geography contrasts sharply with its economy. Physical characteristics and guerilla war fragment the country geographically, yet it has a long tradition of political centrism and macroeconomic stability. Recently, with political and economic decentralization, there has been some weakening of macroeconomic performance. The authors explore institutional arrangements that have helped Colombia manage the fiscal aspects of decentralization, despite the country's political problems. Fiscal decentralization proceeded rapidly in Colombia. Education, health, and much infrastructure provision have been decentralized to the departmentos and municipios. Decentralization has led to substantial but not overwhelming problems, both in maintaining fiscal balance nationally ( as resources are transferred of subnational levels) and in preventing unsustainable deficits by the subnational governments. The problems have arisen because central government interference prevents departments from controlling their costs and because of expectations of debt bailouts. Both are legacies of the earlier pattern of management from the center, and some recent changes - especially about subnational debt - may improve matters. Colombia's traditional political process has had difficulty dealing with problems of decentralization because traditional parties are weak in internal organization and have lost de facto rule over substantial territories. The fiscal problems of subnational government have been contained, however, because subnational governments are relatively weak politically and the central government, for the time being, has been able to enforce restrictions on subnational borrowing.
Interannual Consistency in Fractal Snow Depth Patterns at Two Colorado Mountain Sites

Fractal dimensions derived from log–log variograms are useful for characterizing spatial structure and scaling behavior in snow depth distributions. This study examines the temporal consistency of snow depth scaling features at two sites using snow depth distributions derived from lidar datasets collected in 2003 and 2005. The temporal snow accumulation patterns in these two years were substantially different, but both years represent nearly average 1 April accumulation depths for these sites, with consistent statistical distributions. Two distinct fractal regions are observed in each log–log variogram, separated by a scale break, which indicates a length scale at which a substantial change in the driving processes exists. The lag distance of the scale break is 15 m at the Walton Creek site and 40 m at the Alpine site. The datasets show consistent fractal dimensions and scale break distances between the two years, suggesting that the scaling features observed in spatial snow depth distributions are largely determined by physiography and vegetation characteristics and are relatively insensitive to annual variations in snowfall. Directional variograms also show consistent patterns between years, with smaller fractal dimensions aligned with the dominant wind direction at each site.
Bounding Ext for modules for algebraic groups, finite groups and quantum groups ✩

Given a finite root system Φ, we show that there is an integer c=c(Φ) such that dimExtG1(L,L′)<c, for any reductive algebraic group G with root system Φ and any irreducible rational G-modules L, L′. There also is such a bound in the case of finite groups of Lie type, depending only on the root system and not on the underlying field. For quantum groups, a similar result holds for Extn, for any integer n⩾0, using a constant depending only on n and the root system. When L is the trivial module, the same result is proved in the algebraic group case, thus giving similar bounded properties, independent of characteristic, for algebraic and generic cohomology. (A similar result holds for any choice of L=L(λ), even allowing λ to vary, provided the p-adic expansion of lambda is limited to a fixed number of terms.) In particular, because of the interpretation of generic cohomology as a limit for underlying families of finite groups, the same boundedness properties hold asymptotically for finite groups of Lie type. The results both use, and have consequences for, Kazhdan–Lusztig polynomials. Appendix A proves a stable version, needed for small prime arguments, of Donkin's tilting module conjecture.
Warpage Measurement of Board Assemblies Using Projection MoirÉ System With Improved Automatic Image Segmentation Algorithm

Out-of-plane displacement (warpage) has been a major reliability concern for board-level electronic packaging. Printed wiring board (PWB) and component warpage results from coefficient of thermal expansion (CTE) mismatch among the materials that make up the printed wiring board assembly (PWBA). Warpage occurring during surface-mount reflow process and normal operations may lead to serious reliability problems. PWB/PWBA warpage can be measured by many different optical techniques, among which moire methods have emerged as real-time, noncontact, full-field, and superior techniques with high resolutions. In this paper, a warpage measurement system based on the projection moire technique and improved automatic image segmentation algorithm is presented. In order to use the projection moire system to accurately and separately determine the warpage of a PWB and assembled chip packages in a PWBA, a novel automatic image segmentation algorithm was developed. The algorithm uses mask image models to detect and segment assembled packages from the PWB, and defines their warpage, respectively. This approach resulted in higher resolution and processing rate compared to the original algorithm based on snakes. The warpage of the PWB and chip packages in a PWBA can be successfully determined individually irrespective of the package locations and orientations. Real-time continuous and composite Hermite surface models were generated to evaluate the PWB warpage values underneath packages. The improved segmentation algorithm was integrated with the projection moire system so that the system is able to accurately evaluate the warpage of the PWB and chip packages in a PWBA, respectively.
When Promoters Like Scalpers

If a monopoly supplies a perishable good, such as tickets to a performance, and is unable to price discriminate within a period, the monopoly may benefit from the potential entry of resellers. If the monopoly attempts to intertemporally price discriminate, the equilibrium in the game among buyers is indeterminate when the resellers are not allowed to enter, and the monopoly's problem is not well defined. An arbitrarily small amount of heterogeneity of information among the buyers leads to a unique equilibrium. We show how the potential entry of resellers alters this equilibrium.
Changes in Early- and Late-Stage Colorectal Cancer Incidence During the Era of Screening: 1976-2009

1522 Background: Ideally, screening detects cancer at a more curable stage, and as a result decreases the incidence of subsequent diagnosis at a late stage. Whereas breast cancer screening is sugge...
MORE SOCIAL CAPITAL, LESS EROSION: EVIDENCE FROM PERU'S ALTIPLANO

The debate over sustainable intensification has hinged on private incentives to abate land degradation. Largely missing is the role of social capital in both creating incentives and removing barriers to soil conservation. Yet soil conservation embodies the externality problem that bedevils so many aspects of natural resource management. Action by one farmer to reduce water or wind erosion may benefit neighboring fields by slowing the rate of water or wind movement across those lands. Yet these benefits are not fully captured by the farmer making the conservation investment. However, when economic agents care for one another, these externalities can be internalized, reducing the individual's disincentive to perform a socially level of natural resource conservation. Likewise, community organizations may provide collective capital and labor to overcome adoption barriers faced by individuals. The twin hypotheses that 1) farming practices influence soil erosion and 2) social capital influences the adoption of sustainable farming practices are tested with data from a 1999 survey of 197 farms in the Peruvian Altiplano around Lake Titicaca. The survey used cluster sampling of farms in villages to represent each of three arable agro-ecological zones in the Ilave-Huenque river basin. Relative asset levels were used to stratify resident households within villages. Personal interviews collected a wide range of data on farm household assets, management practices, and status of agricultural natural resources.
Poverty Traps, Aid, and Growth

Abstract This paper examines the empirical relevance of the poverty trap view of underdevelopment. We calibrate simple aggregate growth models in which poverty traps can arise due to either low saving or low technology at low levels of development. We then assess the empirical relevance of these specific mechanisms and their consequences for policy. We find little evidence of the existence of poverty traps based on these two mechanisms. When put to the task of explaining the persistence of low income in African countries, the models require either unreasonable values for key parameters, or else generate counterfactual predictions regarding the relations between key variables. These results call into question arguments in favour of a large scaling-up of aid to the poorest countries that are premised on the existence of such poverty traps.
Did the Devil Make Them Do It? The Effects of Religion in Public Goods and Trust Games*

SUMMARY We examine the extent to which religious affiliation and participation are associated with other-regarding behavior in canonical public goods and bi-lateral trust games. In general, religious affiliation is unrelated to behavior in these experiments; further, there is only weak evidence that attendance at religious services is correlated with behavior in these games. Contrary to popular wisdom and several recent observational studies, religion is not strongly associated with increased cooperation and trust in our controlled experiments.
FISCAL POLICY AS AN INSTRUMENT OF INVESTMENT AND GROWTH

This paper investigates the role of fiscal guarantees in promoting infrastructure investment. Infrastructure is a critical driver of economic growth, but infrastructure entails significant up-front costs that yield benefits after a time lag. Investors hesitate to put their money down on private infrastructure ventures because of the long lag and governments do not give guarantees for reasons of fiscal prudence. The paper argues that governments and large investment guarantee agencies can in many situations give suitably-calibrated guarantees to private projects by exploiting the fact that a guarantee on one project can reduce the risk of another one failing. The paper works out the architecture of such guarantees, which can be fiscally prudent and yet boost investment, especially in infrastructure, and thereby promote growth.
Towards Effective Sentence Simplification for Automatic Processing of Biomedical Text

The complexity of sentences characteristic to biomedical articles poses a challenge to natural language parsers, which are typically trained on large-scale corpora of non-technical text. We propose a text simplification process, bioSimplify, that seeks to reduce the complexity of sentences in biomedical abstracts in order to improve the performance of syntactic parsers on the processed sentences. Syntactic parsing is typically one of the first steps in a text mining pipeline. Thus, any improvement in performance would have a ripple effect over all processing steps. We evaluated our method using a corpus of biomedical sentences annotated with syntactic links. Our empirical results show an improvement of 2.90% for the Charniak-McClosky parser and of 4.23% for the Link Grammar parser when processing simplified sentences rather than the original sentences in the corpus.
Lymphovascular Invasion is Independently Associated With Overall Survival, Cause-Specific Survival, and Local and Distant Recurrence in Patients With Negative Lymph Nodes at Radical Cystectomy

Purpose We hypothesized that bladder cancer patients with associated lymphovascular invasion (LVI) are at increased risk of occult metastases. Methods A multi-institutional group (University of Texas Southwestern [Dallas, TX], Baylor College of Medicine [Houston, TX], Johns Hopkins University [Baltimore, MD]) carried out a retrospective study of 958 patients who underwent cystectomy for bladder cancer between 1984 and 2003. Of patients with transitional-cell carcinoma (n = 776), LVI status was available for 750. LVI was defined as the presence of tumor cells within an endothelium-lined space. Results LVI was present in 36.4% (273 of 750) overall, involving 26% (151 of 581) and 72% (122 of 169) of node-negative and node-positive patients, respectively. Prevalence of LVI increased with higher pathologic stage (9.0%, 23%, 60%, and 78%, for T1, T2, T3, and T4, respectively; P < .001). Using multivariate Cox regression analyses including age, stage, grade, and number of pelvic lymph nodes removed, LVI was an i...
Large system decentralized detection performance under communication constraints

The problem of decentralized detection in a sensor network subjected to a total average power constraint and all nodes sharing a common bandwidth is investigated. The bandwidth constraint is taken into account by assuming non-orthogonal communication between sensors and the data fusion center via direct-sequence code-division multiple-access (DS-CDMA). In the case of large sensor systems and random spreading, the asymptotic decentralized detection performance is derived assuming independent and identically distributed (iid) sensor observations via random matrix theory. The results show that, even under both power and bandwidth constraints, it is better to combine many not-so-good local decisions rather than relying on one (or a few) very-good local decisions.
Pressure-driven flow in a channel with porous walls

The finite-Reynolds-number three-dimensional flow in a channel bounded by one and two parallel porous walls is studied numerically. The porous medium is modelled by spheres in a simple cubic arrangement. Detailed results on the flow structure and the hydrodynamic forces and couple acting on the sphere layer bounding the porous medium are reported and their dependence on the Reynolds number illustrated. It is shown that, at finite Reynolds numbers, a lift force acts on the spheres, which may be expected to contribute to the mobilization of bottom sediments. The results for the slip velocity at the surface of the porous layers are compared with the phenomenological Beavers–Joseph model. It is found that the values of the slip coefficient for pressure-driven and shear-driven flow are somewhat different, and also depend on the Reynolds number. A modification of the relation is suggested to deal with these features. The Appendix provides an alternative derivation of this modified relation
Parking structures: Fuss analogs

For any irreducible real reflection group W with Coxeter number h, Armstrong, Reiner, and the author introduced a pair of $W \times {\mathbb {Z}}_{h}$ -modules which deserve to be called W-parking spaces which generalize the type A notion of parking functions and conjectured a relationship between them. In this paper we give a Fuss analog of their constructions. For a Fuss parameter k?1, we define a pair of $W \times {\mathbb {Z}}_{kh}$ -modules which deserve to be called k-W-parking spaces and conjecture a relationship between them. We prove the weakest version of our conjectures for each of the infinite families ABCDI of finite reflection groups, together with proofs of stronger versions in special cases. Whenever our weakest conjecture holds for W, we have the following corollaries.
Convergence to Purchasing Power Parity at the Commencement of the Euro

We investigate convergence towards Purchasing Power Parity (PPP) within the Euro Zone and between the Euro Zone and its main partners using panel data methods that incorporate serial and contemporaneous correlation. We find strong rejections of the unit root hypothesis, and therefore evidence of PPP, in the Euro Zone for different numeraire currencies, as well as in the Euro Zone plus the United States, with the US dollar as the numeraire currency, starting between 1996 and 1999. The process of convergence towards PPP, however, begins earlier, generally in 1992 or 1993 following the adoption of the Maastricht Treaty.
An improved synthesis of cyclopropanes from homoallenic alcohols

Abstract Treatment of the readily available β-allene tosylates with LDA or nBuLi provides an expeditious, although stereorandom, synthesis of functionalized cyclopropanes which can be easily prepared in high enantiomeric purity.
Simplified security notions of direct anonymous attestation and a concrete scheme from pairings

Direct Anonymous Attestation (DAA) is a cryptographic mechanism that enables remote authentication of a user while preserving privacy under the user’s control. The DAA scheme developed by Brickell, Camenisch, and Chen has been adopted by the Trust Computing Group for remote anonymous attestation of Trusted Platform Module, which is a small hardware device with limited storage space and communication capability. In this paper, we provide two contributions to DAA. We first introduce simplified security notions of DAA including the formal definitions of user controlled anonymity and traceability. We then propose a new DAA scheme from elliptic curve cryptography and bilinear maps. The lengths of private keys and signatures in our scheme are much shorter than the lengths in the original DAA scheme, with a similar level of security and computational complexity. Our scheme builds upon the Camenisch–Lysyanskaya signature scheme and is efficient and provably secure in the random oracle model under the LRSW (stands for Lysyanskaya, Rivest, Sahai and Wolf) assumption and the decisional Bilinear Diffie–Hellman assumption.
The politics of stock market development

ABSTRACT This article locates the political determinants of stock market development in the distributional cleavages among voters and interest groups. Our argument questions the prevailing explanation about the role of partisanship in the literature, where it is usually assumed that left governments frighten investors. To the extent that financial development is translated into higher levels of investment that increases labor demand, workers and the parties representing them will adopt policies and regulations that favor the capitalization of financial markets. We explore the empirical content of our hypothesis against several competing explanations: the legal origins school, which argues common law proxies stronger investor protections than civil law; the electoral law school, which argues proportional representation provides weaker protections than do majoritarian ones; the institutional economics view, which argues that checks on policy-making discretion such as veto gates protect the property rights o...
On the equivalence between the effective cosmology and excursion set treatments of environment

In studies of the environmental dependence of structure formation, the large-scale environment is often thought of as providing an effective background cosmology: for example the formation of structure in voids is expected to be just like that in a less dense universe with appropriately modified Hubble and cosmological constants. However, in the excursion set description of structure formation which is commonly used to model this effect, no explicit mention is made of the effective cosmology. Rather, this approach uses the spherical evolution model to compute an effective linear theory growth factor, which is then used to predict the growth and evolution of non-linear structures. We show that these approaches are, in fact, equivalent: a consequence of Birkhoff's theorem. We speculate that this equivalence will not survive in models where the gravitational force law is modified from an inverse square, potentially making the environmental dependence of clustering a good test of such models.
Robust Stability of Plants With Mixed Uncertainties and Quantitative Feedback Theory

Quantitative Feedback Theory (QFT) has often been criticized for lack of a rigorous mathematical theory to support its claims. Yet it is known to be a very effective design methodology. In this paper, we re-examine QFT and state several results that confirm the validity of this highly effective framework proposed by Horowitz. Also provided are some additional insights into the QFT methodology that may not be immediately apparent. We consider three important fundamental questions: (i) whether or not a QFT design is robustly stable, (ii) does a robust stabilizer exist, and (iii) does a controller assuring robust QFT performance exist
Enrico Barone's ‘Ministry of Production’: Content and Context

Abstract Enrico Barone's famous article on economic planning, ‘Il Ministro della Produzione nello Stato Collettivista’ (‘The Ministry of Production in the Collectivist State’), which showed the theoretical possibility of an economically efficient collectivist planned economy, was published in Giornale degli Economisti in 1908. Barone's article has been widely cited, particularly in the comparative economic systems literature, but it has not been very widely read or analysed in recent years, and there is not much literature that places Barone's ‘Ministry’ model in the context of his other works or in its historical, social, or ideological context. The aims of this article are: (a) to analyse and clarify Barone's model in depth; (b) to place it in the context of Barone's other writings and the literature on the subject; and (c) to examine the apparent contradiction between Barone's hostility to socialism and his attempt to formulate the pure theory of the collectivist economy.
Statistical Magic and/or Statistical Serendipity: An Age of Progress in the Analysis of Categorical Data

This essay describes in simple terms some of the major concepts of categorical data analysis (CDA) that have been and will continue to be useful in the analysis of sociological data, examples of which include data in the area of social stratification and mobility, and in many other areas that make use of survey data and/or panel studies data, and in empirical studies of latent types, latent variables, and latent structures. The exposition does not make use of any mathematical formulas, and the only arithmetic used is very simple multiplication, division, and addition. Simple numerical examples, constructed for expository purposes, are used as an aid in describing the concepts of categorical data analysis that are considered in the essay. These concepts include quasi-independence, quasi-symmetry, symmetric association, uniform association, and other related concepts useful in the analysis of mobility tables, and also other concepts that are useful in other areas of study.
Psychophysical evaluation of gamut mapping techniques using simple rendered images and artificial gamut boundaries

Using a paired comparison paradigm, various gamut mapping algorithms were evaluated using simple rendered images and artificial gamut boundaries. The test images consisted of simple rendered spheres floating in front of a gray background. Using CIELAB as our device-independent color space, cut-off values for lightness and chroma, based on the statistics of the images, were chosen to reduce the gamuts for the test images. The gamut mapping algorithms consisted of combinations of clipping and mapping the original gamut in linear piecewise segments. Complete color space compression in RGB and CIELAB was also tested. Each of the colored originals (R,G,B,C,M,Y, and Skin) were mapped separately in lightness and chroma. In addition, each algorithm was implemented with saturation (C/sup *//L/sup */) allowed to vary or retain the same values as in the original image. Pairs of test images with reduced color gamuts were presented to twenty subjects along with the original image. For each pair the subjects chose the test image that better reproduced the original. Rank orders and interval scales of algorithm performance with confidence limits were then derived. Clipping all out-of-gamut colors was the best method for mapping chroma. For lightness mapping at low lightness levels and high lightness levels particular gamut mapping algorithms consistently produced images chosen as most like the original. The choice of device-independent color space may also influence which gamut mapping algorithms are best.
Risk Assessment of an Aging Military Aircraft

The paper examines the adequacy of the U.S. Air Force damage tolerance inspection criterion for protecting the safety of the flight of an aging military trainer aircraft. This is done through a risk assessment based on cracks found in teardown inspections of retired wings. The crack population is combined with stress probabilities representing service experience to determine single flight probability of failure and the single aircraft probability of failure after a given time. These quantities are then used as a basis for judging the required inspection interval. For the case studied, the 0.9 probability of detection inspection criterion in the Air Force damage tolerance requirements may be nnconsewative.
A Universal Parallel Two-Pass MDL Context Tree Compression Algorithm

Computing problems that handle large amounts of data necessitate the use of lossless data compression for efficient storage and transmission. We present a novel lossless universal data compression algorithm that uses parallel computational units to increase the throughput. The length- $N$ input sequence is partitioned into $B$ blocks. Processing each block independently of the other blocks can accelerate the computation by a factor of $B$ , but degrades the compression quality. Instead, our approach is to first estimate the minimum description length (MDL) context tree source underlying the entire input, and then encode each of the $B$ blocks in parallel based on the MDL source. With this two-pass approach, the compression loss incurred by using more parallel units is insignificant. Our algorithm is work-efficient, i.e., its computational complexity is $O(N/B)$ . Its redundancy is approximately $B\log(N/B)$ bits above Rissanen's lower bound on universal compression performance, with respect to any context tree source whose maximal depth is at most $\log(N/B)$ . We improve the compression by using different quantizers for states of the context tree based on the number of symbols corresponding to those states. Numerical results from a prototype implementation suggest that our algorithm offers a better trade-off between compression and throughput than competing universal data compression algorithms.
Quantum lower bounds for fanout

We consider the resource bounded quantum circuit model with circuits restricted by thenumber of qubits they act upon and by their depth. Focusing on natural universal setsof gates which are familiar from classical circuit theory, several new lower bounds forconstant depth quantum circuits are proved. The main result is that parity (and hencefanout) requires log depth quantum circuits, when the circuits are composed of singlequbit and arbitrary size Toffoli gates, and when they use only constantly many ancillae.Under this constraint, this bound is close to optimal. In the case of a non-constantnumber a of ancillae and n input qubits, we give a tradeoff between a and the requireddepth, that results in a non-constant lower bound for fanout when a = n1-o(1). We alsoshow that, regardless of the number of ancillae arbitrary arity Toffoli gates cannot besimulated exactly by a constant depth circuit family with gates of bounded arity.
Properties and applications of programs with monotone and convex constraints

We study properties of programs with monotone and convex constraints. We extend to these formalisms concepts and results from normal logic programming. They include the notions of strong and uniform equivalence with their characterizations, tight programs and Fages Lemma, program completion and loop formulas. Our results provide an abstract account of properties of some recent extensions of logic programming with aggregates, especially the formalism of lparse programs. They imply a method to compute stable models of lparse programs by means of off-the-shelf solvers of pseudo-boolean constraints, which is often much faster than the smodels system.