cssi/SciSciGPT-SciSciNet huggingface dataset:
Who Benefited from Trade Liberalization in Mexico? Measuring the Effects on Household Welfare

This study performs an ex-post analysis of the effects of the trade liberalization in Mexico between 1989 and 2000, taking into account regional differences in the Mexican economy. The effects of trade liberalization are first translated into changes in regional prices and wages. Those estimates are plugged into a farm-household model to estimate the effect on households' welfare. The findings suggest that trade liberalization has affected domestic prices and labor income differently both across income groups and geographically across the country, hence producing diverse outcomes on different households. Regarding prices, the results indicate that trade liberalization has lowered relative prices of most non-animal agricultural products and, while reducing the cost of consumption, has reduced households' agricultural income, widening the income gap between urban and rural areas. The findings also show that trade liberalization has had diverse effects on wage rates. Skilled workers, for which trade liberalization has produced an increase in wages, have benefited relative to unskilled workers. Wages of unskilled workers have in many regions decreased as a result of trade liberalization. Similar differences are found in the geographic distribution of the benefits of trade liberalization, with the states closest to the U. S. border gaining threefold more relative to the least developed states in the south. Therefore trade liberalization, although beneficial, has contributed to an increase in inequality between the south and the north of the country, urban and rural areas, and skilled and unskilled labor. From a poverty perspective, the trade liberalization that occurred between 1989 and 2000 has had the direct effect of reducing poverty by about 3 percent, therefore lifting approximately 3 million individuals out of poverty.
Sequential elections with limited information

We develop an incomplete information model of a sequence of elections in a one-dimensional policy space, where voters have no contemporaneous information about candidate positions, and candidates have no information about voter preferences. The only source of information is contemporaneous endorsement data and historical data on the policy positions of previous winning candidates. We define a notion of “stationary rational expectations equilibrium”, and show that such an equilibrium results in outcomes which are equivalent to those that would occur under full information.
Automorphism Groups of Schur Rings

In 1993, Muzychuk [23] showed that the rational Schur rings over a cyclic group Z n are in one-to-one correspondence with sublattices of the divisor lattice of n, or equivalently, with sublattices of the lattice of subgroups of Z n . This can easily be extended to show that for any finite group G, sublattices of the lattice of characteristic subgroups of G give rise to rational Schur rings over G in a natural way. Our main result is that any finite group may be represented as the (algebraic) automorphism group of such a rational Schur ring over an abelian p-group, for any odd prime p. In contrast, over a cyclic group the automorphism group of any Schur ring is abelian. We also prove a converse to the well-known result of Muzychuk [24] that two Schur rings over a cyclic group are isomorphic if and only if they coincide; namely, we show that over a group which is not cyclic, there always exist distinct isomorphic Schur rings.
Using virtual reality to validate system models

To date most validation techniques are highly biased towards calculations involving symbolic representations of problems. These calculations are either formal (in the case of consistency and completeness checks), or informal in the case of code inspections. We believe that an essential type of "evidence" of the correctness of the formalization process must be provided by (i.e., must originate from) human-based calculation. We further believe that human calculation can be significantly amplified by shifting from symbolic representations to graphical representations. This paper describes our preliminary efforts in realizing such a representational shift.
Beating the Random Assignment on Constraint Satisfaction Problems of Bounded Degree

We show that for any odd k and any instance I of the max-kXOR constraint satisfaction problem, there is an efficient algorithm that finds an assignment satisfying at least a 1/2 + Omega(1/sqrt(D)) fraction of I's constraints, where D is a bound on the number of constraints that each variable occurs in. This improves both qualitatively and quantitatively on the recent work of Farhi, Goldstone, and Gutmann (2014), which gave a quantum algorithm to find an assignment satisfying a 1/2 Omega(D^{-3/4}) fraction of the equations. For arbitrary constraint satisfaction problems, we give a similar result for "triangle-free" instances; i.e., an efficient algorithm that finds an assignment satisfying at least a mu + Omega(1/sqrt(degree)) fraction of constraints, where mu is the fraction that would be satisfied by a uniformly random assignment.
Training Needs in School Health Education Research

Abstract The purpose of this paper is to review the history of professional preparation of health educators for the conduct of research, to present several major issues and problems related to school health education research, and to identify the characteristics of present training models. Despite the fact that health education can trace its origin to early in this century, it was not until 1953 that a formal statement on research competencies was formulated. Since that time, however, a great deal of activity has been identified. While several issues have been raised regarding research strategies and techniques used by health educators, current training models hold a great deal of promise for strengthening these efforts. The characteristics of such training models are described.
Recent Advances in Electrocatalytic Reduction of Carbon Dioxide Using Metal-Free Catalysts

As part of the efforts to address the global energy issues, the identification of electrocatalysts for efficient and selective conversion of carbon dioxide to value-added products is a research topic of scientific and technological significance. Metal-free catalysts are considered next-generation, renewable materials that promise to be cost-effective, relative to their metal-containing counterparts, particularly relative to noble-metal-based catalysts. In this article, recent progress toward identification of metal-free catalysts for electrochemical reduction of carbon dioxide is reviewed. These catalysts are classified into four categories, including conducting polymers, pyridinium derivatives, aromatic anion radicals, and heteroatom-doped carbon materials. We provide a detailed investigation of the overall catalytic performance of each material, in terms of the product distribution, overpotential required, Faradaic yield, stability of the catalyst, and reaction mechanism. Several important factors that ...
Matching based augmentations for approximating connectivity problems

We describe a very simple idea for designing approximation algorithms for connectivity problems: For a spanning tree problem, the idea is to start with the empty set of edges, and add matching paths between pairs of components in the current graph that have desirable properties in terms of the objective function of the spanning tree problem being solved. Such matching augment the solution by reducing the number of connected components to roughly half their original number, resulting in a logarithmic number of such matching iterations. A logarithmic performance ratio results for the problem by appropriately bounding the contribution of each matching to the objective function by that of an optimal solution. In this survey, we trace the initial application of these ideas to traveling salesperson problems through a simple tree pairing observation down to more sophisticated applications for buy-at-bulk type network design problems.
Videotaped Confessions and the Genre of Documentary

This essay begins the exploration of two contemporary and related film trends: the recent popular enthusiasm over the previously arty documentary film and the mandatory filming of custodial interrogations and confessions. The history and criticism of documentary film, indeed contemporary movie-going, understands the documentary genre as political and social advocacy (recent examples are Michael Moore's Farenheit 9/11 and Errol Morris's Fog of War). Judges, advocates, and legislatures, however, assume that films of custodial interrogations and confessions reveal a truth and lack a distorting point of view. As this Article explains, the trend at law, although aimed at furthering venerable criminal justice principles, holds a fairly naive view of film's indexical relationship to the lived world and abjures consideration of the contemporary trend in cinema. Understanding the documentary as truth-revealing is a mistake, a mistake which can frustrate (if not undermine) the criminal justice goals of the legislation. Whatever may explain the convergence of filmmaking in the precinct house and a penchant for mainstream documentary movie-going, the trends are shaping contemporary expectations about film in contradictory ways. Investigating these trends together exposes competing norms regarding film as a legal tool and as a knowledge producing discourse. It also situates the criminal justice trend in the context of a long history of filmmaking and critical spectatorship. In light of the growing use of film as a policing mechanism, better understanding of film as both an art and a legal tool is in order.
On per-session performance of an ATM multiplexer with heterogeneous speed links

Our aim in this paper is to provide insight on a session’s performance in the presence of different speed links at an ATM multiplexer. We describe a queueing model for such scenarios considering a finite capacity buffer and bursty traffic with correlated arrivals. We use Markov Modulated Bernoulli Process (MMBP) as the traffic model for the session of interest and model the cross traffic as an MMBP with batch arrivals. We present exact analysis using an evolution method to obtain the steady-state performance measures of the session. To enhance its efficiency, a closed form, partial approximation method is also described. Using numerical results we compare a sessions performance in different scenarios of link speeds, and also study the influence of a few network and traffic characteristics.
Signal detection for MIMO-ISI channels: a unitary linear recovery approach

In this paper, a new detector called unitary linear recovery (ULR) is proposed for MIMO-LSI channels with imprecise channel knowledge. The proposed method seeks the best match between the observation subspace and the Bezout signal subspace by optimizing over valid signaling matrices with structural, finite alphabet, and whiteness constraints. Forcing signal whiteness constraints result in a distinct distance measure (sum of singular values) to be used as the criterion. Algorithmically, the proposed method alternates between forcing signal orthogonality via searching for an optimal unitary linear recovery operator, and forcing Sylvester and finite alphabet constraints on the recovered outputs. Simulations show that ULR may outperform the MMSE detector with exact channel knowledge and ULR with successive interference cancellation gives a very attractive performance.
Race, Income, and College in 25 Years: Evaluating Justice O’Connor’s Conjecture

In Grutter v. Bollinger (2003), Justice Sandra Day O’Connor conjectured that in 25 years affirmative action in college admissions will be unnecessary. We project the test score distribution of black and white college applicants 25 years from now, focusing on the role of black-white family income gaps. Economic progress alone is unlikely to narrow the achievement gap enough in 25 years to produce today’s racial diversity levels with race-blind admissions. A return to the rapid black-white test score convergence of the 1980s could plausibly cause black representation to approach current levels at moderately selective schools, but not at the most selective schools.
Eigenstructure assignment for the control of highly augmented aircraft

Eigenstructure assignment is utilized to design flight control laws for aircraft with many control effectors. We show that a previous eigenstructure design for the Flight Propulsion Control Coupling (FPCC) aircraft lateral dynamics with three control surfaces exhibits a lack of stability robustness because the control distribution matrix is nearly rank-deficient. We present a method for reducing the control space to two dimensions by using the singular value decomposition. After the design is complete, we map the controller back to the original three-dimensional control space. This design approach yields a controller with both smaller gains and improved multivariable stability margins at the aircraft inputs. An interesting charcteristic of the control mapping, as applied to our example, is that the most effective inputs have the larger gains while the less effective inputs have smaller gains.
Efficient target detection for RNA interference

RNA interference (RNAi) is a posttranscriptional gene silencing mechanism used to study gene functions, inhibit viral activities, and treat diseases. Due to the nonspecific effects of RNAi, target validation through target detection is crucial for the success of RNAi experiments. Since target detection involves large amounts of transcriptome-wide searches, computational efficiency is critical. To efficiently detect targets for RNAi design, we develop both sequential and parallel search algorithms using RNA string kernels, which model mismatches, G-U wobbles, and bulges between siRNAs and target mRNAs. Based on tests in S. pombe, C. elegans, and human, our algorithms achieved speedups of 6 orders of magnitude over a baseline implementation. Our design strategy also leads to a framework for efficient, flexible, and portable string search algorithms.
Do consumers pay for one-stop banking? Evidence from a non-standard revenue function

Synergies in providing financial services can reduce costs due to joint production (cost economies of scope) or raise revenues due to joint consumption (revenue economies of scope). Cost economies of scope between bank deposits and loans were found to be small elsewhere. Revenue economies of scope are investigated here for the first time and found to be non-existent over 1978-1990 for both small and large banks and for those on or off the revenue-efficient frontier. The lack of synergies between deposits and loans--where benefits are most likely to occur--suggests few synergies from an expansion of banking powers.
The Jury Is Still Out on the Need for an International Criminal Court

After languishing in the shadow of international ambivalence for some seventy years,1 the proposal for the creation of an international criminal court is enjoying a modern revival. Within the last year, the United Nations International Law Commission ("ILC"),2 the U.N. Crime Congress, a conference of international scholars in Italy, and the International Law Section of the American Bar Association ("ABA") all have endorsed the concept of an international criminal court.3 Moreover, the 101st Congress (1989-90), on its final day, passed legislation calling on the Executive Branch to explore the need for the establishment of such a court and requiring the Executive Branch to report its findings by October 1, 1991. 4 Even senior officials of the U.S. Department of State recently have acknowledged that "the time is probably riper than ever to
Re-Gauging Groupoid, Symmetries and Degeneracies for Graph Hamiltonians and Applications to the Gyroid Wire Network

We study a class of graph Hamiltonians given by a type of quiver representation to which we can associate (non)-commutative geometries. By selecting gauging data, these geometries are realized by matrices through an explicit construction or a Kan extension. We describe the changes in gauge via the action of a re-gauging groupoid. It acts via matrices that give rise to a noncommutative 2-cocycle and hence to a groupoid extension (gerbe). We furthermore show that automorphisms of the underlying graph of the quiver can be lifted to extended symmetry groups of re-gaugings. In the commutative case, we deduce that the extended symmetries act via a projective representation. This yields isotypical decompositions and super-selection rules. We apply these results to the primitive cubic, diamond, gyroid and honeycomb wire networks using representation theory for projective groups and show that all the degeneracies in the spectra are consequences of these enhanced symmetries. This includes the Dirac points of the G(yroid) and the honeycomb systems.
Soda Taxes and the Prices of Sodas and Other Drinks: Evidence from Mexico

To combat a growing obesity problem, Mexico imposed a nationwide tax on drinks with added sugar, popularly referred to as a “soda tax,” effective January 2014. Since the tax took effect nationwide, there is no conventional control group that can be used as a baseline to estimate how the tax affected prices. Instead, I make use of control commodities, that is, untaxed goods that are not substitutes for the taxed drinks. I analyze data from Mexico’s Consumer Price Index program, using the synthetic control method and a time-series intervention analysis. In both cases I employ a placebo inference approach akin to permutation inference. The estimates show that soda prices rose by more than the amount of the tax. There is less evidence that the prices of potential substitutes rose, possibly indicating that consumers did not switch to those products after the tax took effect. Some simple calculations suggest that the soda price increase could lead to a two- to three-pound reduction in mean weight, which amounts to roughly 1%–2% of mean body mass.
Optical and Metallurgical Characterization of Molybdenum Laser Mirrors

A study has been performed to determine the correlation between the microstructure, metallurgical processing, and surface finish of eight specially selected molybdenum (Mo) specimens from various sources. Samples of bar and plate stock produced from pure Mo either arc-cast or pressed and sintered, and TZM (Ti-Zr-Mo) Mo alloy were examined in the form of optically polished 1 ½-inch- (3.86-cm-) diameter discs. Metallurgical characterization included hardness measurements, grain size and shape determinations from polished and etched sections, scanning electron microscopy, and Auger electron spectroscopy. Optical characterization consisted of measurements of total integrated scattering, rms roughness, height distribution functions, and autocovariance. In some cases, the surface roughness of as-polished mirror surfaces could be directly related to grain structure and substructure as revealed by etching. These observations and their implications for the selection of Mo starting stock to be used in the production of low-scatter laser mirrors will be discussed.
Evaluation of minimization software based on performance profile techniques

An approach to evaluation of minimization software developed from the principles of the performance profile is summarized.
A cryptographic framework for the controlled release of certified data

It is usually the case that before a transaction can take place, some mutual trust must be established between the participants. On-line, doing so requires the exchange of some certified information about the participants. The easy solution is to disclose one’s identity and reveal all of one’s certificates to establish such a trust relationship. However, it is clear that such an approach is unsatisfactory from a privacy point of view. In fact, often revealing any information that uniquely corresponds to a given individual is a bad idea from the privacy point of view. In this survey paper we describe a framework where for each transaction there is a precise specification of what pieces of certified data is revealed to each participant. We show how to specify transactions in this framework, give examples of transactions that use it, and describe the cryptographic building blocks that this framework is built upon. We conclude with bibliographic notes on the state-of-the-art in this area.
Gabriela Mistral y la reforma educacional de José Vasconcelos

Resumen es: En 1922 Jose Vasconcelos hace un viaje a America del Sur e invita en Chile a Lucila Godoy Alcayaga, que llegara a conocerse como Gabriela Mistral, para ...
LENGTH, MULTIPLICITY, AND MULTIPLIER IDEALS

Let (R, m) be an n-dimensional regular local ring, essentially of finite type over a field of characteristic zero. Given an m-primary ideal a of R, the relationship between the singularities of the scheme defined by a and those defined by the multiplier ideals J(a c ), with c varying in Q + , are quantified in this paper by showing that the Samuel multiplicity of a satisfies e(n) ≥ (n + k) n /c n whenever J(a c ) C m k+1 . This formula generalizes an inequality on log canonical thresholds previously obtained by Ein, Mustata and the author of this paper. A refined inequality is also shown to hold for small dimensions, and similar results valid for a generalization of test ideals in positive characteristics are presented.
The Changing Asymmetric Information Component of REIT Spreads: A Study of Anticipated Announcements

This study examines the risk-compensating behavior of REIT market makers. The bid-ask spread is hypothesized to compensate market makers for three costs: asymmetric information, order processing, and inventory. As the market maker's perceived likelihood of transacting with a better-informed individual increases (decreases), the percentage of the spread that is attributed to asymmetric information will increase (decrease). This study examines the asymmetric information component of the bid-ask spread immediately prior to and following REIT dividend announcements and REIT funds from operations announcements during 1995 and 1996. The asymmetric information component increases the day before and then declines subsequent to dividend announcements of small and equity REITs. Asymmetric information costs increase following funds from operations announcements.
Model Checking of Security Protocols with Pre-configuration

Security protocols are very vulnerable to design errors. Thus many techniques have been proposed for validating the correctness of security protocols. Among these, general model checking is one of the preferred methods. Using tools such as Murϕ, model checking can be performed automatically. Thus protocol designers can use it even if they are not proficient in formal techniques. Although this is an attractive approach, state space explosion prohibits model checkers from validating secure protocols with a significant number of communicating participants. In this paper, we propose “model checking with pre-configuration” which is a “divide-and-conquer” approach that reduces the amount of memory needed for verification. The verification time is also reduced since the method permits the use of symmetry more effectively in model checking. The performance of the method is shown by checking the Needham-Schroeder-Lowe Public-Key protocol using Murϕ.
Radar Signal Detection

Owing to the existence of noise and interference, radar signal detection has to be treated as a statistical problem, regardless of whether the signal under detection is deterministic. This statistical formalism of radar signal detection theory can be applied to all types of radar signals without restriction. To understand radar signal detection, noise has to be described quantitatively. A time-limited deterministic signal can be described as a time series, and a periodic deterministic signal can be represented as a Fourier series. In contrast, noise cannot be represented as a deterministic function in the time or frequency domains. In other words, we cannot predict a noise-contaminated radar signal with absolute certainty. However, with available noise information such as the expectation, the power, or even the probability distribution of noise, we can select a criterion on which to base our decision. Keywords: radar signal; noise; intereference; Fourier series; bandpass signal; coherent detection; noncoherent detection
Correlated defaults, temporal correlation, expert information and predictability of default rates

ABSTRACTDependence among defaults both across assets and over time is an important characteristic of financial risk. A Bayesian approach to default rate estimation is proposed and illustrated using prior distributions assessed from an experienced industry expert. Two extensions of the binomial model are proposed. The first allows correlated defaults yet remains consistent with Basel II’s asymptotic single-factor model. The second adds temporal correlation in default rates through autocorrelation in the systemic factor. Implications for the predictability of default rates are considered. The single-factor model generates more forecast uncertainty than does the parameter uncertainty. A robustness exercise illustrates that the correlation indicated by the data is much smaller than that specified in the Basel II regulations.
Impact of colloidal transport on radionuclide migration in the natural environment

: Colloids are small, less than one micron particles found in all natural water. They are composed of inorganic, organic or microbial material and can act as carriers for low-solubility radionuclides, such as plutonium, americium and cesium. Some actinides can hydrolyze to form an oxide or other pure phases called intrinsic colloids. However, the presence of colloids does not necessarily guarantee the facilitation of the transport of radionuclides. Other factors such as colloid filtration, stability, groundwater flow rate, groundwater chemistry, and desorption/dissolution rates of the radionuclides are all important parameters that determine colloid facilitated transport of a specific radionuclide. This chapter focuses on our current progress in understanding the conditions and mechanisms that enhance colloidal transport. Additional emphasis is given to field sites where investigations have shown colloids to facilitate the far-field transport of radionuclides. Understanding the biogeochemical conditions that facilitate the transport of low-solubility radionuclides can help us design high-level waste repositories that minimize these conditions, thus limiting transport in the subsurface.
On the Power of Ambainis’s Lower Bounds

The polynomial method and the Ambainis's lower bound (or Alb, for short) method are two main quantum lower bound techniques. While recently Ambainis showed that the polynomial method is not tight, the present paper aims at studying the power and limitation of Alb's. We first use known Alb's to derive Ω(n 1.5 ) lower bounds for BIPARTITENESS, BIPARTITENESS MATCHING and GRAPH MATCHING, in which the lower bound for BIPARTITENESS improves the previous Q(n) one. We then show that all the three known Ambainis's lower bounds have a limitation √ N . min{C 0 (f), C 1 (f)}, where C 0 (f) and C 1 (f) are the 0- and 1-certificate complexity, respectively. This implies that for many problems such as TRIANGLE, k-CLIQUE, BIPARTITENESS and BIPARTITE/GRAPH MATCHING which draw wide interest and whose quantum query complexities are still open, the best known lower bounds cannot be further improved by using Ambainis's techniques. Another consequence is that all the Ambainis's lower bounds are not tight. For total functions, this upper bound for Alb's can be further improved to min{√C 0 (f)C 1 (f), √N.CI(f)}, where CI(f) is the size of max intersection of a 0-and a 1-certificate set. Again this implies that Alb's cannot improve the best known lower bound for some specific problems such as AND-OR TREE, whose precise quantum query complexity is still open. Finally, we generalize the three known Alb's and give a new Alb style lower bound method, which may be easier to use for some problems.
A new characterization of probabilities in Bayesian networks

We characterize probabilities in Bayesian networks in terms of algebraic expressions called quasi-probabilities. These are arrived at by casting Bayesian networks as noisy AND-OR-NOT networks, and viewing the subnetworks that lead to a node as arguments for or against a node. Quasi-probabilities are in a sense the "natural" algebra of Bayesian networks: we can easily compute the marginal quasi-probability of any node recursively, in a compact form; and we can obtain the joint quasi-probability of any set of nodes by multiplying their marginals (using an idempotent product operator). Quasi-probabilities are easily manipulated to improve the efficiency of probabilistic inference. They also turn out to be representable as square-wave pulse trains, and joint and marginal distributions can be computed by multiplication and complementation of pulse trains.
An Econometric Analysis of Trade Creation and Trade Diversion in Mercosur: the Case of Paraguay

This paper analyzes the effects of Mercosur on Paraguayan import flows using detailed trade values to identify patterns of trade creation and trade diversion at aggregate and disaggregate commodity levels. It is well know that the share of foreign trade with respect to GDP is larger for small countries. Consequently, the effects of a trade agreement between large and small countries are likely to be larger in small economies. I use a variant of the gravity model employing a reparameterization of the difference-in-difference estimator to analyze import flows over time from member and non-member countries. Additionally, I explicitly include zero trade flows and implement a Heckman sample selection correction along with country fixed effects. I find the creation of Mercosur has increased average regional imports by 266% since 1995, which is evidence of trade creation. The greatest import expansions have been in Beverages and Tobacco and Animal and vegetable oils & fats. Finally, I do not find statistically significant evidence of trade diversion in any of the ten commodity categories.
The “Gutting” of Grutter: White Racial Innocence and Post-racialism in the Abigail Fisher v. University of Texas Austin Oral Arguments

Abigail Fisher v. University of Texas at Austin (2013) is the continuation of the Supreme Court’s negotiation of the constitutionality of race-conscious admissions practices in educational settings. In this article, I undertake a Critical Race discourse analysis of the Fisher case oral arguments to examine how the Supreme Court constructs discourses on race and affirmative action. I argue that the Fisher oral arguments use a “white racial innocence” discourse that constructs whiteness and white people as unfair victims of race-conscious policies. The white racial innocence discourse corresponds with the Court’s emerging use of post-racialism. This analysis looks at post-racialism as a context for pedagogy as discourses around race established by the Court can translate into higher education. The Fisher case impacts the pedagogical context for higher education, with wider implications for students of color, especially if post-racialism is adopted by college campuses.
Explaining property tax collections in developing countries: the case of Latin America

This paper analyzes the problem of collecting property taxes in fiscally decentralized developing economies. The property tax is arguably the most important source of own revenues for local governments around the world, and economists generally agree that, although imperfect, the property tax is a good local tax. In practice, however, the property tax does not always become a productive revenue source and local governments do not gain the fiscal autonomy required to realize the benefits of fiscal decentralization. This problem is rather common among developing economies and particularly severe in Latin America. One of the main reasons for the poor tax performance of Latin American countries seems to be the lack of administrative capacity at the local level. This problem is notably aggravated, we argue, by a deficient design of the fiscal decentralization system. We also identify the main determinants of property tax performance in Latin American countries, and provide guidance for future reforms in the region.
Dynamics of North American breeding bird populations

Population biologists have long been interested in the variability of natural populations1,2,3,4,5,6. One approach to dealing with ecological complexity is to reduce the system to one or a few species, for which meaningful equations can be solved. Here we explore an alternative approach7,8 by studying the statistical properties of a data set containing over 600 species, namely the North American breeding bird survey9. The survey has recorded annual species abundances over a 31-year period along more than 3,000 observation routes10. We now analyse the dynamics of population variability using this data set, and find scaling features in common with inanimate systems composed of strongly interacting subunits11. Specifically, we find that the distribution of changes in population abundance over a one-year interval is remarkably symmetrical, with long tails extending over six orders of magnitude. The variance of the population over a time series increases as a power-law with increasing time lag, indicating long-range correlation in population size fluctuations12. We also find that the distribution of species lifetimes (the time between colonization and local extinction) within local patches is a power-law with an exponential cutoff imposed by the finite length of the time series. Our results provide a quantitative basis for modelling the dynamics of large species assemblages.
Model-predictive cascade mitigation in electric power systems with storage and renewables, Part I: Theory and implementation

A novel model predictive control (MPC) scheme is developed for mitigating the effects of severe line-overload disturbances in electrical power systems. A piece-wise linear convex approximation of line losses is employed to model the effect of transmission line power flow on conductor temperatures. Control is achieved through a receding-horizon model predictive control (MPC) strategy which alleviates line temperature overloads and thereby prevents the propagation of outages. The MPC strategy adjusts line flows by rescheduling generation, energy storage and controllable load, while taking into account ramp-rate limits and network limitations. In [1], the MPC strategy is illustrated through simulation of the IEEE RTS-96 network, augmented to incorporate energy storage and renewable generation.
Coseismic and postseismic stress rotations due to great subduction zone earthquakes

[1] The three largest recent great subduction zone earthquakes (2011 M9.0 Tohoku, Japan; 2010 M8.8 Maule, Chile; and 2004 M9.2 Sumatra-Andaman) exhibit similar coseismic rotations of the principal stress axes. Prior to each mainshock, the maximum compressive stress axis was shallowly plunging, while immediately after the mainshock, both the maximum and minimum compressive stress axes plunge at ∼45°. Dipping faults can be oriented for either reverse or normal faulting in this post-mainshock stress field, depending on their dip, explaining the observed normal-faulting aftershocks without requiring a complete reversal of the stress field. The significant stress rotations imply near-complete stress drop in the mainshocks, with >80% of the pre-mainshock stress relieved in the Tohoku and Maule earthquakes and in the northern part of the Sumatra-Andaman rupture. The southern part of the Sumatra-Andaman rupture relieved ∼60% of the pre-mainshock stress. The stress axes rotated back rapidly in the months following the Tohoku and Maule mainshocks, and similarly in the southern part of the Sumatra-Andaman rupture. A rapid postseismic rotation is possible because the near-complete stress drop leaves very little “background” stress at the beginning of the postseismic reloading. In contrast, there has been little or no postseismic rotation in the northern part of the Sumatra-Andaman rupture over the 7 years since the mainshock. All M ≥8.0 subduction earthquakes since 1990 with an adequate number of pre- and post-mainshock events were evaluated, and not all show similar coseismic stress rotations. Deeper earthquakes exhibit smaller coseismic stress rotations, likely due to increasing deviatoric stress with depth.
Convergence of IPsec in presence of resets

IPsec is the current security standard for the Internet Protocol IP. According to this standard, a selected computer pair (p, q) in the Internet can be designated a "security association". This designation guarantees that all sent IP messages whose original source is computer p and whose ultimate destination is computer q cannot be replayed in the future (by an adversary between p and q) and still be received by computer q as fresh messages from p. This guarantee is provided by adding increasing sequence numbers to all IP messages sent from p to q. Thus, p needs to always remember the sequence number of the last sent message, and q needs to always remember the sequence number of the last received message. Unfortunately, when computer p or q is reset these sequence numbers can be forgotten, and this leads to two bad possibilities: unbounded number of fresh messages from p can be discarded by q, and unbounded number of replayed messages can be accepted by q. In this paper, we propose two operations, "SAVE" and "FETCH", to prevent these possibilities. The SAVE operation can be used to store the last sent sequence number in persistent memory of p once every Kp sent messages, and can be used to store the last received sequence number in persistent memory of q once every Kq received messages. The FETCH operation can be used to fetch the last stored sequence number for a computer when that computer wakes up after a reset. We show that the following three conditions hold when SAVE and FETCH are adopted in both p and q. First, when p is reset, at most 2Kp sequence numbers will be lost but no fresh message sent from p to q will be discarded if no message reorder occurs. Second, when q is reset, the number of discarded fresh messages is bounded by 2Kq. In either case, no replayed message will be accepted by q.
Attractive and Repulsive Gravity

We discuss the circumstances under which gravity might be repulsive rather than attractive. In particular we show why our standard solar system distance scale gravitational intuition need not be a reliable guide to the behavior of gravitational phenomena on altogether larger distance scales such as cosmological, and argue that in fact gravity actually gets to act repulsively on such distance scales. With such repulsion a variety of current cosmological problems (the flatness, horizon, dark matter, universe age, cosmic acceleration and cosmological constant problems) are then all naturally resolved.
Scientific and Technical Support for the Galileo Net Flux Radiometer Experiment

This report describes work in support of the Galileo Net Flux Radiometer (NFR), an instrument mounted on the Galileo probe, a spacecraft designed for entry into and direct measurements of Jupiter's atmosphere. Tasks originally proposed for the post launch period are briefly as follows: attend and support PSG (Project Science Group) and other project science meetings; support in-flight checkouts; maintain and keep safe the spare instrument and GSE (Ground Support Equipment); organize and maintain documentation; finish NFR calibration measurements, documentation, and analysis; characterize and diagnose instrument anomalies; develop descent data analysis tools; and science data analysis and publication. Because we had the capability to satisfy a project support need we also subsequently proposed and were funded to make ground- based observations of Jupiter during the period surrounding the Galileo arrival at Jupiter, using the Swedish Solar Telescope at La Palma, Canary Islands. The following section (11) provides background information on the NFR instrument.
Insurance and liquidity : panel evidence

This paper presents evidence that balance sheet effects are critical determinants of both the likelihood of a crisis and of income losses following a crisis. The paper tests the validity of “insurance” and “liquidity” models of currency crisis. Both models predict that the occurrence of a balance of payments crisis is conditional on the health of the nation’s accounts vis-a-vis the rest of the world. Problems in the balance sheet either cause a financial crisis that develops into a run on the Central Bank, or generate a run on the Central Bank once contingent liabilities exceed reserves and the yield differential moves against domestic assets. Estimations of crisis likelihoods based on several specifications of single and simultaneous equation probit models confirm that output losses following the crisis are persistent and conditional on the balance sheet indicator, i.e. the ratio of the stock of gross external liabilities to assets. Measures of contingent liabilities, capital flight, and financial depth perform well as crisis predictors, and the marginal effects on the probability of a crisis are of the expected sign. The panel data set covers the time period 1973 through 2003 for 90 countries.
The Effect of Potential Environmental Liabilities on Earnings Response Coefficients

In this study, we investigate the implication of potential environmental liabilities for the reliability (noisiness) of accounting information as it manifests itself in the magnitude of an earnings...
A causal Bayesian model for the diagnosis of appendicitis

The causal Bayesian approach is based on the assumption that effects (e.g., symptoms) that are not conditionally independent with respect to some causal agent (e.g., a disease) are conditionally independent with respect to some intermediate state caused by the agent, (e.g., a pathological condition). This paper describes the development of a causal Bayesian model for the diagnosis of appendicitis. The paper begins with a description of the standard Bayesian approach to reasoning about uncertainty and the major critiques it faces. The paper then lays the theoretical groundwork for the causal extension of the Bayesian approach, and details specific improvements we have developed. The paper then goes on to describe our knowledge engineering and implementation and the results of a test of the system. The paper concludes with a discussion of how the causal Bayesian approach deals with the criticisms of the standard Bayesian model and why it is superior to alternative approaches to reasoning about uncertainty popular in the AI community.
Integrating probabilistic rules into neural networks: a stochastic EM learning algorithm

The EM-algorithm is a general procedure to get maximum likelihood estimates if part of the observations on the variables of a network are missing. In this paper a stochastic version of the algorithm is adapted to probabilistic neural networks describing the associative dependency of variables. These networks have a probability distribution, which is a special case of the distribution generated by probabilistic inference networks. Hence both types of networks can be combined allowing to integrate probabilistic rules as well as unspecified associations in a sound way. The resulting network may have a number of interesting features including cycles of probabilistic rules, hidden 'unobservable' variables, and uncertain and contradictory evidence.
Entrepreneurship and Philanthropy in American Capitalism

American capitalism differs from all other forms of industrial capitalism is its historical focus on both the creation of wealth (entrepreneurship) and the reconstitution of wealth (philanthropy). Philanthropy is part of the implicit social contract that continuously nurtures and revitalizes economic prosperity. Much of the new wealth created historically has been given back to the community, to build up the great social institutions that have a positive feedback on future economic growth. This entrepreneurship-philanthropy nexus has not been fully explored by either economists or the general public. The purpose of this paper is to suggest that American philanthropists – especially those who have made their own fortunes – create foundations that, in turn, contribute to greater and more widespread economic prosperity through knowledge creation. If we do not analyze philanthropy we can understand neither how economic development occurred nor what accounts for American economic dominance.
Knots with compressible thin levels

Thin position has contributed to many advances in the study of knots and 3–manifolds. Gabai defined thin position for knots in S and employed the notion in his proof of Property R [5]. Subsequently, thin position was utilized in the solution to the knot complement problem (see Gordon and Luecke [7]), the recognition problem for S (see Rubinstein [12] and Thompson [14]) and the leveling of unknotting tunnels (see Goda, Scharlemann and Thompson [6]).
Refereeing the public health

Between January 2009 and October 2013, 49 states and the District of Columbia passed laws focusing on mitigating the consequences of traumatic brain injuries (TBIs) in organized youth sports. Using historical, contextual, and empirical methods, this Article describes the content, goals, and structure of youth sports TBI laws, while hypothesizing about their underlying legislative logic and long-term public health consequences. The Article's empirical evidence suggests two key findings: first, that a dominant interest group, the National Football League, helped to define the problem and its associated solutions for the vast majority of states, thus curving the legislative story are in favor of its policy prescriptions; second, that existing youth sports TBI laws are focused on secondary, not primary, prevention, and may thus shift attention away from more comprehensive solutions. Finally, the Article explains why such state laws will likely fail to substantially resolve the larger untackled problem--significantly reducing the overall rate and number of TBIs in youth sports. After explaining why existing state youth sports TBI laws fail to accomplish this broader goal, the Article queries whether alternative policy or public health measures might offer more robust solutions. Language: en
Contact process on generalized Fibonacci chains: infinite-modulation criticality and double-log periodic oscillations.

We study the nonequilibrium phase transition of the contact process with aperiodic transition rates using a real-space renormalization group as well as Monte Carlo simulations. The transition rates are modulated according to the generalized Fibonacci sequences defined by the inflation rules A $\ensuremath{\rightarrow}$ AB${}^{k}$ and B $\ensuremath{\rightarrow}$ A. For $k=1$ and 2, the aperiodic fluctuations are irrelevant, and the nonequilibrium transition is in the clean directed percolation universality class. For $k\ensuremath{\ge}3$, the aperiodic fluctuations are relevant. We develop a complete theory of the resulting unconventional ``infinite-modulation'' critical point, which is characterized by activated dynamical scaling. Moreover, observables such as the survival probability and the size of the active cloud display pronounced double-log periodic oscillations in time which reflect the discrete scale invariance of the aperiodic chains. We illustrate our theory by extensive numerical results, and we discuss relations to phase transitions in other quasiperiodic systems.