cssi/SciSciGPT-SciSciNet huggingface dataset:
Matching Polyhedral Terrains Using Overlays of Envelopes

For a collection $\F$ of $d$-variate piecewise linear functions of overall combinatorial complexity $n$, the lower envelope $\E(\F)$ of $\F$ is the pointwise minimum of these functions. The minimization diagram $\M(\F)$ is the subdivision of $\reals^d$ obtained by vertically (i.e., in direction $x_{d+1}$) projecting $\E(\F)$. The overlay $\O(\F,\G)$ of two such subdivisions $\M(\F)$ and $\M(\G)$ is their superposition. We extend and improve the analysis of de Berg et al. \cite{bgh-vdt3s-96} by showing that the combinatorial complexity of $\O(\F,\G)$ is $\Omega(n^d \alpha^{2}(n))$ and $O(n^{d+\eps})$ for any $\eps>0$ when $d \ge 2$, and $O(n^2 \alpha(n) \log n)$ when $d=2$. We also describe an algorithm that constructs $\O(\F,\G)$ in this time.We apply these results to obtain efficient general solutions to the problem of matching two polyhedral terrains in higher dimensions under translation. That is, given two piecewise linear terrains of combinatorial complexity $n$ in $\reals^{d+1}$, we wish to find a translation of the first terrain that minimizes its distance to the second, according to some distance measure. For the perpendicular distance measure, which we adopt from functional analysis since it is natural for measuring the similarity of terrains, we present a matching algorithm that runs in time $O(n^{2d+\eps})$ for any $\eps>0$. Sharper running time bounds are shown for $d \le 2$. For the directed and undirected \Hd\ distance measures, we present a matching algorithm that runs in time $O(n^{d^2+d+\eps})$ for any $\eps>0$.
Colonialism, Learning and Convergence: A Comparison of India and Taiwan

ABSTRACT This article combines the traditional learning model with recent theory of economic growth using Maddison's long-run real GDP per capita data. We first discuss the performance of India and Taiwan in the world economy. While economic theory suggests that India could have grown faster than Taiwan, this was not the case after the Second World War. We identify differences in terms of learning in the development experience of the two countries under colonial rule. The colonial distortion in industrial and agricultural development appeared to be more important in India than in Taiwan. The most important factors, however, were health and education. We then derive learning coefficients of India with the United Kingdom, Taiwan with Japan, and Japan with the United States through the pre-war and post-war periods. Long-run coefficients of learning are estimated. Using the conventional unit root-based test of convergence, we show that the model of learning leads to a logistic model of economic growth. We the...
Posets of geometric graphs

A geometric graph Ḡ is a simple graph drawn in the plane, on points in general position, with straight-line edges. We call Ḡ a geometric realization of the underlying abstract graph G . A geometric homomorphism f : Ḡ → H is a vertex map that preserves adjacencies and crossings (but not necessarily non-adjacencies or non-crossings). This work uses geometric homomorphisms to introduce a partial order on the set of isomorphism classes of geometric realizations of an abstract graph G . Set Ḡ ≼ Ĝ if Ḡ and Ĝ are geometric realizations of G and there is a vertex-injective geometric homomorphism f : Ḡ → Ĝ . This paper develops tools to determine when two geometric realizations are comparable. Further, for 3 ≤ n ≤ 6, this paper provides the isomorphism classes of geometric realizations of P n , C n and K n , as well as the Hasse diagrams of the geometric homomorphism posets (resp., P n , C n , K n ) of these graphs. The paper also provides the following results for general n : each of P n and C n has a unique minimal element and a unique maximal element; if k ≤ n then P k (resp., C k ) is a subposet of P n (resp., C n ); and K n contains a chain of length n − 2.
The Ethics of “Commercial Bribery”: Integrative Social Contract Theory Meets Transaction Cost Economics

This article provides an ISCT analysis of commercial bribery focused on transaction cost economics. In the language of Antitrust, commercial bribery is a form of vertical arrangement subject to the same efficiency analysis that has found other vertical arrangements potentially beneficial to consumers. My analysis shows that actions condemned as commercial bribery in the Honda case (1996) may well have benefited Honda’s dealer network once promotional free riding and other forms of rent seeking by dealers are considered. I propose that the term “commercial bribery” should be avoided until after an ISCT analysis shows that the community is likely to have been harmed. The term “third-party payments” is a more ethically neutral term with which to begin the analysis.
From Social Theory to Policy Design

Little attention has been given in policy analysis to the creative process of designing solutions to public policy problems. There are a number of difficulties in applying macro-level theories – whether from economics, sociology, philosophy or macro-systems theory – in the policy process. Any macro-level theory will tend to provide inadequate guidance in one or more of three aspects of policy-making: a model of causation, a model for evaluating alternatives and outcomes, and a model of how interventions operate. Our current knowledge about which policy strategies work best under which conditions is at best rudimentary. Academic disciplinary perspectives focus on a narrow repertoire of policy instruments. What is required is a design focus which draws on instruments associated with a range of disciplines and professions. A design perspective involves both a systematic process for generating basic strategies and a framework for comparing them. Such an approach will require at least the following elements: (1) the characteristics of problems (scale, collectiveness, certainty, predictability, independence); (2) characteristics of goals (value-laden, operational, process of goal-setting); (3) characteristics of instruments (suitability of different instruments).
Thermally-induced, geometrically nonlinear response of symmetrically laminated composite plates

This paper discusses the thermally-induced geometrically nonlinear response of symmetrically laminated composite plates. The plate response is due to a temperature increase that is uniform in the plane of the plate but has a slight gradient through the thickness. The case of a completely uniform temperature increase but with an initial out-of-plane imperfection in the plate is also considered. Because they are closely allied problems, thermal buckling and postbuckling are discussed. Using variational methods in conjunction with a Rayleigh-Ritz formulation, these responses are investigated for two laminates, a (±45/0/90)s and a (±4502)s, under two different simple support conditions, fixed and sliding. The effects of the principal material axes not being aligned with the edges of the plate, referred to here as material axis skewing, are also investigated. The study concludes that while differences between buckling temperatures for the two support conditions are small, support conditions can have a large influence on the thermally-induced nonlinear response. In general, plates with fixed simple supports deflect out-of-plane more than plates with sliding simple supports. In addition, support conditions can influence modal interaction. Skewing of the material axes decreases the buckling temperatures of both laminates and, like fixed support conditions, causes increased deflections. Skewing also influences modal interaction.
Fields of Power, Forests of Discontent: Culture, Conservation, and the State in Mexico

Enduring differences between protected areas and local people have produced few happy compromises, but at the Calakmul Biosphere Reserve in the southern Mexican state of Campeche, government agents and thousands of local people collaborated on an expansive program to alleviate these tensions a conservation-development agenda that aimed to improve local people's standard of living while preserving natural resources. Calakmul is home to numerous endangered species and raises a common question: How can environmental managers and citizens reconcile competing ecological desires? For a brief time in the 1990s, collaborations at Calakmul were heralded as a vital example of melding local management, forest conservation, and economic development. In Fields of Power, Forests of Discontent, Nora Haenn questions the rise and fall of this conservation program to examine conservation at the intersection of national-international agendas and local political-economic interests. While other assessments of such programs have typically focused on why they do or do not succeed, Haenn instead considers conservation's encounter with people's everyday lives and how those experiences affect environmental management. Haenn explores conservation and development from two perspectives: first regionally, to look at how people used conservation to create a new governing entity on a tropical frontier once weakly under national rule; then locally, focusing on personal histories and aspects of community life that shape people's daily lives, farming practices, and immersion in development programs even though those programs ultimately fail to resolve economic frustrations. She identifies how key political actors, social movements, and identity politics contributed to the instability of the Calakmul alliance. Drawing on extensive interviews with Reserve staff, including its director, she connects regional trends to village life through accounts of disputes at ejido meetings and the failure of ejido development projects. In the face of continued difficulty in creating a popular conservation in Calakmul, Haenn uses lessons from people's lives history, livelihood, village organization, expectations to argue for a "sustaining conservation," one that integrates social justice and local political norms with a new, more robust definition of conservation. In this way, Fields of Power, Forests of Discontent goes beyond local ethnography to encourage creative discussion of conservation's impact on both land and people.
Thermal conductivity and thermal rectification in graphene nanoribbons: a molecular dynamics study.

We have used molecular dynamics to calculate the thermal conductivity of symmetric and asymmetric graphene nanoribbons (GNRs) of several nanometers in size (up to ∼4 nm wide and ∼10 nm long). For symmetric nanoribbons, the calculated thermal conductivity (e.g., ∼2000 W/m-K at 400 K for a 1.5 nm × 5.7 nm zigzag GNR) is on the similar order of magnitude of the experimentally measured value for graphene. We have investigated the effects of edge chirality and found that nanoribbons with zigzag edges have appreciably larger thermal conductivity than nanoribbons with armchair edges. For asymmetric nanoribbons, we have found significant thermal rectification. Among various triangularly shaped GNRs we investigated, the GNR with armchair bottom edge and a vertex angle of 30° gives the maximal thermal rectification. We also studied the effect of defects and found that vacancies and edge roughness in the nanoribbons can significantly decrease the thermal conductivity. However, substantial thermal rectification is ob...
Asset prices and liquidity in an exchange economy

I develop an asset-pricing model in which financial assets are valued for their liquidity–the extent to which they are useful in facilitating exchange–as well as for being claims to streams of consumption goods. The implications for average asset returns, the equity-premium puzzle and the risk-free rate puzzle, are explored in a version of the model that nests the work of Mehra and Prescott (1985).
On agents and grids: Creating the fabric for a new generation of distributed intelligent systems

The semantic grid is the result of semantic web and grid researchers building bridges in recognition of the shared vision and research agenda of both fields. This paper builds on prior experiences with both agents and grids to illustrate the benefits of bringing agents into the mix. Because semantic grids represent and reason about knowledge declaratively, additional capabilities typical of agents are then possible including learning, planning, self-repair, memory organization, meta-reasoning, and task-level coordination. These capabilities would turn semantic grids into cognitive grids. Only a convergence of these technologies will provide the ingredients to create the fabric for a new generation of distributed intelligent systems.
Palladium-catalyzed decarboxylative allylic alkylation of diastereomeric β-ketoesters

The palladium-catalyzed decarboxylative allylic alkylation of diastereomeric β-ketoesters derived from 4-tert-butylcyclohexanone is described. These experiments were performed to elucidate our understanding of stereoablative enantioconvergent catalysis. A detailed analysis of the product distribution, including stereochemical outcome of the products, is included. These studies also reveal an interesting example of selectivity that is governed by competing modes of substrate and catalyst control.
Common representation of pain and negative emotion in the midbrain periaqueductal gray

Human neuroimaging offers a powerful way to connect animal and human research on emotion, with profound implications for psychological science. However, the gulf between animal and human studies remains a formidable obstacle: human studies typically focus on the cortex and a few subcortical regions such as the amygdala, whereas deeper structures such as the brainstem periaqueductal gray (PAG) play a key role in animal models. Here, we directly assessed the role of PAG in human affect by interleaving in a single fMRI session two conditions known to elicit strong emotional re
Finding motifs in the twilight zone

We introduce the notion of a multiprofile and use it for finding subtle motifs in DNA sequences. Multiprofiles generalize the notion of a profile and allow one to detect subtle consensus sequences that escape detection by the standard profiles. Our MULTIPROFILER algorithm outperforms other leading motif finding algorithms in a number of synthetic models. Moreover, it can be shown that in some previously studied motif models, MULTIPROFILER is capable of pushing the performance envelope to its theoretical limits.
Structural Phases of Bounded Three-Dimensional Screened Coulomb Clusters (Finite Yukawa System)

The formation of 3-D dust clusters within a complex plasma modeled as a spatially confined Yukawa system is simulated using the box_tree code. Similar to unscreened Coulomb clusters, the occurrence of concentric shells with characteristic occupation numbers was observed. Both the occupation numbers and radii were found to depend on the Debye length. Ground and low-energy metastable states of the shielded 3-D Coulomb clusters were determined for 4<N<20. The structure and energy of the clusters in different states was analyzed for various Debye lengths. Structural phase transitions, including intershell structural phase transitions and intrashell structural phase transitions, were observed for varying Debye length and the critical value for transitions calculated
QCD Corrections to Scalar Diquark Production at Hadron Colliders

We calculate the next-to-leading order QCD corrections to quark-quark annihilation to a scalar resonant state (“diquark”) in a color representation of antitriplet or sextet at the Tevatron and LHC energies. At the LHC, we find the enhancement (K-factor) for the antitriplet diquark is typically about 1.31–1.35, and for the sextet diquark is about 1.22–1.32 for initial-state valence quarks. The full transverse-momentum spectrum for the diquarks is also calculated at the LHC by performing the soft gluon resummation to the leading logarithm and all orders in the strong coupling.
HILBERT TRANSFORM ASSOCIATED WITH FINITE MAXIMAL SUBDIAGONAL ALGEBRAS

Let ℳ be a von Neumann algebra with a faithful normal trace τ, and let H∞ be a finite, maximal. subdiagonal algebra of ℳ. We prove that the Hilbert transform associated with H∞ is a linear continuous map from L1 (ℳ, τ) into L1.∞ (ℳ, τ). This provides a non-commutative version of a classical theorem of Kolmogorov on weak type boundedness of the Hilbert transform. We also show that if a positive measurable operator b is such that b log+b ∈ L1 (ℳ, τ) then its conjugate b, relative to H∞ belongs to L1 (ℳ, τ). These results generalize classical facts from function algebra theory to a non-commutative setting.
Quantum modeling of distributed object computing

Distributed object computing is gaining rapid notice in the computer engineering community. However, few tools exist for the design and modeling of distributed object systems. Clearly, large scale and mission critical systems are most affected by this deficiency. To attain a level of tractability in large scale design and verification, dynamic models are essential. The paper introduces two modeling components. The LCN model supports the definition of real-world network topologies and multicomputer systems. The DCO model provides a system-independent method of representing complex, object oriented computing structures. These components are assigned random variables that provide a basis for dynamic behavior. By mapping DCO software onto LCN hardware, the complete OSM (Object System Mapping) model is created. It is shown that OSM systems can model all modes of distributed object behavior found in the current state of Object Request Broker (ORB) technology while under the constraints of modern network structures. The paper concludes with a qualitative analysis of these behaviors and sets the foundation for a distributed object simulation facility. >
THE LYON HYPOTHESIS

A curious imbalance appears to occur in nature—the possession of two X chromosomes by one sex (usually the female) compared with only one X in the other sex. Thus, all genes on the X in the female are present in a double dose when compared with the male. Yet most such genes produce the same effect in both sexes. An intriguing theory to account for this equalization of expression has recently been proposed, and the investigation should enhance our comprehension of X chromosome aberrations, sex differences, and the basic mechanisms of gene action in the developing embryo and the maturing organism.
Yukawa coupling unification in supersymmetric models

We present an updated assessment of the viability of t−b−τ Yukawa coupling unification in supersymmetric models. For the superpotential Higgs mass parameter μ > 0, we find unification to less than 1% is possible, but only for GUT scale scalar mass parameter m 16 ~ 8−20 TeV, and small values of gaugino mass m 1/2400 GeV. Such models require that a GUT scale mass splitting exists amongst Higgs scalars with m H u 2 < m H d 2 . Viable solutions lead to a radiatively generated inverted scalar mass hierarchy, with third generation and Higgs scalars being lighter than other sfermions. These models have very heavy sfermions, so that unwanted flavor changing and CP violating SUSY processes are suppressed, but may suffer from some fine-tuning requirements. While the generated spectra satisfy b→sγ and (g−2)μ constraints, there exists tension with the dark matter relic density unless m 163 TeV. These models offer prospects for a SUSY discovery at the Fermilab Tevatron collider via the search for 12→3l events, or via gluino pair production. If μ < 0, Yukawa coupling unification to less than 5% can occur for m 16 and m 1/21−2 TeV. Consistency of negative μ Yukawa unified models with b→sγ, (g−2)μ , and relic density Ωh 2 all imply very large values of m 1/2 typically greater than about 2.5 TeV, in which case direct detection of sparticles may be a challenge even at the LHC.
Nonlinear Response of Composite Panels Under Combined Acoustic Excitation and Aerodynamic Pressure

A e nite element formulation is presented for the analysis of the large dee ection response of composite panels subjected to high acoustic excitation and aerodynamic pressure at supersonic e ow. The e rst-order shear defor- mation theory is considered for laminated composite plates, and the von Karm´ an nonlinear strain -displacement relations are employed for panel large dee ection response. The e rst-order piston theory aerodynamics and the simulated Gaussian white noise are employed for the aerodynamic and acoustic loads, respectively. The nonlinear equationsofmotion foranarbitrarily laminated compositepanelsubjectedto combined aerodynamicand acoustic pressures are formulated e rst in structure node degrees of freedom. The system equations are then transformed and reduced to a set of coupled nonlinear equations in modal coordinates. Modal participation is dee ned and the in vacuo modes to be retained in the analysis are based on the modal participation values. Numerical results include root mean square values of maximum dee ections, dee ection and strain response time histories, probability distributions, power spectrum densities, and skewness and kurtosis. Results showed that combined acoustic and aerodynamic loads have to be considered for panel analysis and design at high dynamic pressure values.
An Expectancy Theory Motivation Approach to Peer Assessment

Group projects are an important component of higher education, and the use of peer assessment of students' individual contributions to group projects has increased. The researchers employed an expectancy theory approach and an experimental design in a field setting to investigate conditions that influence students' motivation to rate their peers' contributions to team projects. Two questionnaires were also developed and tested by the researchers. This research found that rating format and rating frequency significantly interacted to influence student motivation and their perceptions of their team. Research findings reveal peer assessment to be a complex process in need of further study. Two peer assessment instruments and peer assessment training materials are provided along with suggestions for future research.
Are Suburban Firms More Likely to Discriminate against African-Americans?

Abstract This paper assesses whether African-Americans are more likely to experience employment discrimination in the suburbs relative to the central city. We compare central city–suburban differences in racial hiring outcomes for firms where whites are in charge of hiring to the comparable difference for firms where blacks are in charge of hiring. Both suburban black and white employers hire fewer blacks than their central-city counterparts. This geographic gap among black employers is at least as large as that of white employers. Assuming no discrimination by black employers in any location, this implies that the probability of experiencing discrimination does not vary over space. Black firms, however, are substantially more likely to hire black workers regardless of location.
Mg‐doped InN and InGaN – Photoluminescence, capacitance–voltage and thermopower measurements

The bandgap range of InGaN extends from the near-IR (InN, 0.65 eV) to the ultraviolet. To exploit this wide tuning range in light generation and conversion applications, pn junctions are required. The large electron affinity of InN (5.8 eV) leads to preferential formation of native donor defects, resulting in excess electron concentration in the bulk and at surfaces and interfaces. This creates difficulties for p-type doping and/or measuring of the bulk p-type activity. Capacitance–voltage measurements, which deplete the n-type surface inversion layer, have been used to show that Mg is an active acceptor in InN and Inx Ga1–xN for 0.2 < x < 1.0, i.e. over the entire composition range. Mg acceptors can be compensated by irradiation-induced native donors. Thermopower measurements were used to provide definitive evidence that Mg-doped InN has mobile holes between 200 K and 300 K. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
Short-term Outdoor Temperature Change and Emergency Department Visits for Asthma Among Children: A Case-Crossover Study

Although weather changes are known to cause asthma symptoms, their impact on asthma-related health-care utilization is poorly understood. The objective of the present study was to determine the association between short-term outdoor temperature change and asthma-related emergency department (ED) visits among children 3-18 years of age in Detroit, Michigan, in 2000-2001. Descriptive analyses of patient and ED visit characteristics were performed. A case-crossover study utilizing time-stratified controls was conducted to determine the impact of maximum temperature change and change rate measured during 4-, 8-, 12-, and 24-hour periods. Multivariable conditional logistic regression demonstrated the relation between ED visits and temperature change after controlling for other weather and pollutant measures. There were 4,804 asthma-related ED visits during the study period, and they occurred most frequently in the fall and during morning hours. The case-crossover study showed a statistically significant inverse relation between ED visits and maximum 24-hour temperature change after adjustment for climatic factors (for temperature change, odds ratio = 0.992, P = 0.04; for temperature change rate, odds ratio 0.972, P = 0.01). The association persisted after air pollutant measures were added to the model, although the association was not significant. Despite the finding that a greater 24-hour temperature change decreased the risk of asthma-related ED visits, the overall results suggested a negligible association with short-term temperature change.
Compositional effect on the pressure derivatives of bulk modulus of silicate melts

Abstract Although the bulk moduli ( K T 0 ) of silicate melts have a relatively narrow range of values, the pressure derivatives of the isothermal bulk modulus ( K T 0 ′ ) can assume a broad range of values and have an important influence on the compositional dependence of the melt compressibility at high pressure. Based on the melt density data from sink/float experiments at high pressures in the literature, we calculate K T 0 ′ using an isothermal equation of state (EOS) (e.g., Birch–Murnaghan EOS and Vinet EOS) with the previously determined values of room-pressure density ( ρ 0 ) and room-pressure bulk modulus ( K T 0 ). The results show that best estimates of K T 0 ′ vary considerably from ~ 3 to ~ 7 for different compositions. K T 0 ′ is nearly independent of Mg # (molar Mg/(Mg + Fe)), but decreases with SiO 2 content. Hydrous melts have anomalously small K T 0 ′ leading to a high degree of compression at high pressures. For anhydrous melts, K T 0 ′ is ~ 7 for peridotitic melts, ~ 6 for picritic melts, ~ 5 for komatiitic melts, and ~ 4 for basaltic melts.
The Effects of Social Spending on Economic Activity: Empirical Evidence from a Panel of OECD Countries

The aim of this paper is to assess the effects of social spending on economic activity. Using a panel of OECD countries from 1980 to 2005, the results show that social spending has expansionary effects on GDP. In particular, we found that an increase of 1% of social spending increases GDP by about 0.1 percentage point, which, given the share of social spending to GDP, corresponds to a multiplier of about 0.6. The effect is larger in periods of severe downturns. Among its subcategories, social spending devoted to Health and Unemployment benefits are those that have greatest effects. Social spending also positively affects private consumption while has negligible effects on investment. The empirical results are economically and statistically significant, and robust.
Scaled Correlations of Critical Points of Random Sections on Riemann Surfaces

In this paper we prove that as N goes to infinity, the scaling limit of the correlation between critical points z1 and z2 of random holomorphic sections of the N-th power of a positive line bundle over a compact Riemann surface tends to 2/(3π2) for small \(\sqrt{N}|z_{1}-\nobreak z_{2}|\). The scaling limit is directly calculated using a general form of the Kac-Rice formula and formulas and theorems of Pavel Bleher, Bernard Shiffman, and Steve Zelditch.
Using Dempster-Shafer's belief-function theory in expert systems

The main objective of this paper is to describe how Dempster-Shafer’s (DS) theory of belief functions fits in the framework of valuation-based systems (VBS). Since VBS serve as a framework for managing uncertainty in expert systems, this facilitates the use of DS belief-function theory in expert systems.
Export diversification in twelve European and Central Asian countries and the role of the commodity boom

This paper examines export diversification along the product and market dimensions for selected countries in the Europe and Central Asia region and, more generally, export performance. While the latter is extraordinary, with average export growth rates above 10 percent, the evidence on diversification is less impressive, and hints at a role played by the interaction of natural resource abundance and the commodity price boom. A cross-country analysis including 171 economies suggests that the region's resource rich countries are less diversified than would be expected given their resource endowments, level of development, and size. The commodity boom period was associated with an increase in concentration for the resource rich along the product dimension: they did not increase the number of products exported and became more reliant on oil and gas. During the same period, the resource poor increased their export product scope while maintaining other concentration indices unchanged. A similar but milder pattern is found for diversification along the destination dimension.
Elucidation of methanogenic coenzyme biosyntheses: from spectroscopy to genomics

Methanogenesis, the anaerobic production of methane from CO2 or simple carbon compounds, requires seven organic coenzymes. This review describes pathways for the biosynthesis of methanofuran, 5,6,7,8-tetrahydromethanopterin, coenzyme F420, coenzyme M (2-mercaptoethanesulfonic acid) and coenzyme B (7-mercaptoheptanoyl-L-threonine phosphate). Spectroscopic evidence for the pathways is reviewed and recent efforts are described to identify and characterize the biosynthetic enzymes from methanogenic archaea. The literature from 1971 to September 2001 is reviewed, and 169 references are cited.
A covariant entropy conjecture

We conjecture the following entropy bound to be valid in all space-times admitted by Einstein's equation: let A be the area of any two-dimensional surface. Let L be a hypersurface generated by surface-orthogonal null geodesics with non-positive expansion. Let S be the entropy on L. Then S ≤ A/4. We present evidence that the bound can be saturated, but not exceeded, in cosmological solutions and in the interior of black holes. For systems with limited self-gravity it reduces to Bekenstein's bound. Because the conjecture is manifestly time reversal invariant, its origin cannot be thermodynamic, but must be statistical. It thus places a fundamental limit on the number of degrees of freedom in nature.
An application of the linear quadratic tracking problem to economic stabilization policy

Short-term economic stabilization policy is approached as a problem in optimal control. The optimal control problem is defined as a dual discrete-time tracking problem (nominal state and nominal policy trajectories are tracked) for a linear time-invariant system with a quadratic cost functional. This problem is solved analytically, and the solution is applied to a 28-state variable quarterly econometric model. The experimental results demonstrate that this approach is valuable both as a tool for policy planning and as a method of analyzing the dynamic properties of econometric models.
Copper-catalyzed asymmetric [4+1] cycloadditions of enones with diazo compounds to form dihydrofurans.

This report describes the use of a planar-chiral bipyridine ligand to achieve the first diastereo- and enantioselective copper-catalyzed [4+1] cycloadditions of enones with diazo compounds to produce highly substituted 2,3-dihydrofurans. The method is applied to a catalytic asymmetric synthesis of a deoxy-C-nucleoside.
Kenya's infrastructure: a continental perspective

In the past decade, infrastructure contributed 0.5 percentage points to Kenya's annual per capita GDP growth. Raising the countrys infrastructure endowment to that of Africa's middle-income countries could increase that contribution by 3 percentage points. Several accomplishments are notable. More than 90 percent of the population has access to GSM cell signals. A successful public-private partnership in air transport has made Kenya's airline a top carrier in the region and its international airport a key gateway to Africa. Institutional reforms in the power sector have reduced the burden of subsidies on the public by approximately 1 percent of GDP. But the power sector continues to pose Kenya's greatest infrastructure challenge. Over the next decade, current capacity will have to double. A second challenge is to improve the efficiency of operations at the Port of Mombasa. Other concerns include low levels of access to household services, underfunding of road maintenance, and negative progress on the Millennium Development Goals for water supply and sanitation. Addressing Kenya's infrastructure deficit will require sustained expenditures of approximately $4 billion per year (20 percent of GDP) over the next decade. As of 2006, Kenya needed and additional $2.1 billion per year (11 percent of GDP) to meet that funding goal. The gap could be halved through the use of more efficient technologies to meet infrastructure targets in the transport and WSS sectors. If Kenya is unable to increase infrastructure spending, it could nevertheless meet infrastructure targets in 18 years by eliminating existing inefficiencies in infrastructure sectors.
Learning optimally diverse rankings over large document collections

Most learning to rank research has assumed that the utility of different documents is independent, which results in learned ranking functions that return redundant results. The few approaches that avoid this have rather unsatisfyingly lacked theoretical foundations, or do not scale. We present a learning-to-rank formulation that optimizes the fraction of satisfied users, with a scalable algorithm that explicitly takes document similarity and ranking context into account. We present theoretical justifications for this approach, as well as a near-optimal algorithm. Our evaluation adds optimizations that improve empirical performance, and shows that our algorithms learn orders of magnitude more quickly than previous approaches.
Improvement of tissue analysis and classification using optical coherence tomography combined with Raman spectroscopy

Optical coherence tomography (OCT) provides significant advantages of high resolution (approaching the histopathology level) real-time imaging of tissues without use of contrast agents. Based on these advantages, the microstructural features of tumors can be visualized and detected intra-operatively. However, it is still not clinically accepted for tumor margin delineation due to poor specificity and accuracy. In contrast, Raman spectroscopy (RS) can obtain tissue information at the molecular level, but does not provide real-time imaging capability. Therefore, combining OCT and RS could provide synergy. To this end, we present a tissue analysis and classification method using both the slope of OCT intensity signal vs depth and the principle components from the RS spectrum as the indicators for tissue characterization. The goal of this study was to understand prediction accuracy of OCT and combined OCT/RS method for classification of optically similar tissues and organs. Our pilot experiments were performed on mouse kidneys, livers, and small intestines (SIs). The prediction accuracy with five-fold cross validation of the method has been evaluated by the support vector machine (SVM) method. The results demonstrate that tissue characterization based on the OCT/RS method was superior compared to using OCT structural information alone. This combined OCT/RS method is potentially useful as a noninvasive optical biopsy technique for rapid and automatic tissue characterization during surgery.
Dispersed Federalism as a New Regional Governance for Homeland Security

State and local officials complain about their lack of involvement in disaster plans issued by the Department of Homeland Security (DHS). Their complaints point to a common theme: the reorganization that produced the DHS complicated shared governance. States and localities carry out most of the work of homeland security, but the federal government's guidelines and grants shape much of what subnational governments do. This article offers an interpretation of the complaints of emergency management officials and a proposal for dispersing federal homeland security personnel and resources out of Washington, DC, to FEMA regions. Dispersing federal agencies to the regions they oversee offers an alternative to pure centralization and decentralization that combines the task and location specificity of major approaches to federalism.
The BEAR accelerator

The Beam Experiments Aboard Rocket (BEAR) accelerator is the major component of an experiment designed to demonstrate the operation of an ion accelerator in space and to characterize the exoatmospheric propagation of a neutral particle beam. It is designed to produce a 10-mA (equivalent), 1-MeV, neutral hydrogen beam in 50- mu s pulses at 5 Hz. The accelerator consists of a 30-kV, H/sup -/ injector, a 1-MeV radiofrequency quadrupole, two 425-MHz RF amplifiers, a gas-cell neutralizer, beam optics, a vacuum system, diagnostics, and controls. The design has been constrained by the need for a light-weight rugged system that would operate autonomously. The accelerator has undergone extensive environmental and operational laboratory testing in preparation for launch. The results of testing on the ground test stand are reported. >
THE INDEX OF REDUCIBILITY OF PARAMETER IDEALS IN LOW DIMENSION

In this paper we present results concerning the following ques- tion: If M is a finitely-generated module with finite local cohomologies over a Noetherian local ring (A, m), does there exist an integer l such that every parameter ideal for M contained in m l has the same index of reducibility? We show that the answer is yes if dim M = 1 or if dim M = 2 and depth M > 0. This research is closely related to work of Goto-Suzuki and Goto-Sakurai; Goto-Sakurai have supplied an answer of yes in case M is Buchsbaum.
Compensation of Laser Thermal Depolarization Using Free Space

Thermally induced birefringence in a single-transverse-mode laser for moderate pumping is well compensated when the rod is double-passed after reflection from a mirror one Rayleigh range away from the rod. The depolarized light is in a spatial (1, 1) mode and the relative Gouy phase shift between the fundamental and depolarized modes in propagating a Rayleigh range leads to good compensation.
Copper-catalyzed direct preparation of diaryl sulfides from aryl iodides using potassium thiocyanate as a sulfur transfer reagent

Abstract A method for direct preparation of diaryl sulfides from aryl iodides using potassium thiocyanate as a sulfur-transfer agent is reported. A catalyst system comprising of a simple copper salt, tetrabutylammonium bromide as a phase-transfer agent and water as the solvent is used. Microwave heating at 200 °C for 60 min allows for the conversion of a range of aryl iodides to the corresponding diaryl sulfides.
Divergent regioselectivity in photoredox-catalyzed hydrofunctionalization reactions of unsaturated amides and thioamides

A direct method to construct 2-oxazolines and 2-thiazolines from corresponding allylic amides and thioamides is reported. The redox-neutral intramolecular hydrofunctionalization is enabled by a dual catalyst system comprised of 9-mesityl-N-methyl acridinium tetrafluoroborate and phenyl disulphide and exhibits complete selectivity for the anti-Markovnikov regioisomeric products. The cyclization of allylic thioamides is postulated to operate via a modified mechanism in which oxidation of the thioamide, rather than the alkene, is responsible for the observed reactivity.
Budget Adjustments in Response to Spending Variances: Evidence of Ratcheting of Local Government Expenditures

This paper examines the degree to which government administrators incorporate prior year spending variances into current year budgets. Government administrators have incentives to increase their budgets, and constraints on government spending are weaker than those found in the private sector. Therefore, we expect budget increases associated with prior year government overspending (actual exceeds budget) to be larger than decreases associated with underspending of the same amount. This differential response is called ratcheting. We examine budgets for 1,034 Texas school districts (1995 through 2002), and find budget ratcheting in operating expenditures and the subcategories of instructional and non‐instructional expenditures. Ratcheting is most pronounced for non‐instructional expenditures. We also find that budget ratcheting is more pronounced when controls on government spending are likely to be weaker. Specifically, budget ratcheting is more pronounced for school districts that operate in a less competi...
The Islamic city – Historic Myth, Islamic Essence, and Contemporary Relevance

At the present time of resurgence in Islamic beliefs, the question of the Islamic city has once again come to the fore. In many parts of the Arab world, and especially in Saudi Arabia and the Gulf, urban planners with a new found respect for the great achievements of the past are searching for ways to reproduce in today's cities some of the patterns of city building that have been identified as Islamic. They have been influenced, whether wittingly or not, by a body of literature produced by western Orientalists purporting to describe the essence of the Islamic city. The purpose of this article is, in Part I, to examine and criticize some of the basic works in that tradition and then, after deconstructing the concept of the Islamic city, to build up, in Part II, a somewhat different, and hopefully more dynamic and analytic model. The article ends with a brief discussion of whether and in what ways it would be feasible or desirable to build contemporary cities on Islamic principles.
Advances in electrohydrodynamic conduction pumping

A detailed review of progress-to-date in the field of electrohydrodynamic conduction pumping is presented. Analytical, numerical, and experimental research studies that have been published in this field are summarized and a detailed scientific overview of the conduction pumping model is provided. Conduction pumping has already been investigated successfully to resolve several commonplace issues relating to pumping, flow-distribution, and heat transfer and these applications are also presented.
Direct CP Violation in Untagged B-Meson Decays

Direct CP violation can exist in untagged, neutral B-meson decays to certain self-conjugate, hadronic final states. As a necessary condition, the resonances which appear therein must permit the identification of distinct, CP-conjugate states--in analogy to stereochemistry, we term such states ''CP-enantiomers.'' These states permit the construction of CP-even and CP-odd amplitude combinations and of observables sensitive to their interference, which are non-zero if direct CP violation is present. The decay B {yields} {pi}{sup +}{pi}{sup -}{pi}{sup 0}, containing the distinct CP-conjugate states {rho}{sup +}{pi}{sup -} and {rho}{sup -}{pi}{sup +}, provides one such example of a CP-enantiomeric pair. We illustrate the possibilities in various multi-particle final states.
Low-temperature properties of anisotropic superconductors with kondo impurities

We present a self-consistent theory of superconductors in the presence of Kondo impurities, using large-N slave-boson methods to treat the impurity dynamics. The technique is tested on the s-wave case and shown to give good results compared to other methods forT K >T c . We calculate low temperature thermodynamic and transport properties for various superconducting states, including isotropic s-wave and representative anisotropic model states with line and point nodes on the Fermi surface.
Synergistic Interaction Between ATRP and RAFT: Taking the Best of Each World*

This review covers recent developments on the combination of atom transfer radical polymerization (ATRP) and reversible addition–fragmentation chain transfer (RAFT) polymerization to produce well controlled (co)polymers. This review discusses the relative reactivity of the R group in ATRP and RAFT, provides a comparison of dithiocarbamate (DC), trithiocarbonate (TTC), dithioester (DTE), and xanthate versus bromine or chlorine, and an optimization of catalyst/ligand selection. The level of control in iniferter polymerization with DC was greatly improved by the addition of a copper complex. New TTC inifers with bromopropionate and bromoisobutyrate groups have been prepared to conduct, concurrently or sequentially, ATRP from Br-end groups, ATRP from the TTC moiety, and RAFT polymerization from the TTC moiety, depending on the combination of monomer and catalyst employed in the reaction. The use of concurrent ATRP/RAFT (or copper-catalyzed RAFT polymerization or ATRP with dithioester leaving groups), resulted in improved control over the synthesis of homo- and block (co)polymers and allowed preparation of well-defined high-molecular-weight polymers exceeding 1 million. Block copolymers that could not be prepared previously have been synthesized by sequential ATRP and RAFT polymerization using a bromoxanthate inifer. A simple, versatile, and one-step method involving atom-transfer radical addition–fragmentation (ATRAF) for the preparation of various chain transfer agents (including DC, DTE, and xanthate) in high purity is discussed and a one-pot, two-step polymerization starting with a RAFT agent synthesized by ATRAF, followed by polymerization, is demonstrated.
Past and Present Grasslands of Southern Texas and Northeastern Mexico

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Rapid Synthesis of Crystalline Spinel Tin Nitride by a Solid‐State Metathesis Reaction

Spinel tin nitride (Sn 3 N 4 ) was prepared by high-pressure solid-state metathesis reactions. Tin tetraiodide was reacted with lithium nitride and ammonium chloride in a piston-cylinder apparatus at 623 K and 2.5 GPa. Powder X-ray diffraction combined with Rietveld refinement confirmed the spinel structure, with a lattice constant of a = 9.0144(1) A. Raman spectroscopy revealed five active vibrational modes at 160, 252, 416, 524, and 622 cm -1 , which are consistent with the spinel structure. Mid-infrared spectroscopy exhibited only a Sn-N stretching mode at 547 cm -1 . Transmission electron microscopy was used to reveal particle size and morphology. Electron probe microanalysis was used to verify the elemental composition.