cssi/SciSciGPT-SciSciNet huggingface dataset:
On a Cohen---Lenstra heuristic for Jacobians of random graphs

In this paper, we make specific conjectures about the distribution of Jacobians of random graphs with their canonical duality pairings. Our conjectures are based on a Cohen---Lenstra-type heuristic saying that a finite abelian group with duality pairing appears with frequency inversely proportional to the size of the group times the size of the group of automorphisms that preserve the pairing. We conjecture that the Jacobian of a random graph is cyclic with probability a little over .7935. We determine the values of several other statistics on Jacobians of random graphs that would follow from our conjectures. In support of the conjectures, we prove that random symmetric matrices over $${\mathbb {Z}}_p$$Zp, distributed according to Haar measure, have cokernels distributed according to the above heuristic. We also give experimental evidence in support of our conjectures.
Enumeration of tilings of quartered aztec rectangles

We generalize a theorem of W. Jockusch and J. Propp on quartered Aztec diamonds by enumerating the tilings of quartered Aztec rectangles. We use subgraph replacement method to transform the dual graph of a quartered Aztec rectangle to the dual graph of a quartered lozenge hexagon, and then use Lindstr o m-Gessel-Viennot methodology to find the number of tilings of a quartered lozenge hexagon.
Cuspidal local systems and graded Hecke algebras, III

We prove a strong induction theorem for graded Hecke algebras and we classify the tempered and square integrable representations of such algebras using methods of equivariant homology.
Laser acceleration with open waveguides

A unified framework based on solid-state open waveguides is developed to overcome all three major limitations on acceleration distance and hence on the feasibility of two classes of laser acceleration. The three limitations are due to laser diffraction, acceleration phase slippage, and damage of waveguide structure by a high power laser. The two classes of laser acceleration are direct-field acceleration and ponderomotive-driven acceleration. Thus the solutions provided here encompass all mainstream approaches for laser acceleration, either in vacuum, gases or plasmas.
A Price Discrimination Analysis of Monetary Policy

Monetary policy is analysed within a model that appeals to legal restrictions on private intermediation to explain the coexistence of currency and interest-bearing default-free bonds. The interaction between such legal restrictions and monetary policy is illustrated in a version of the overlapping generations model. The model shows that legal restrictions and the use of both currency and bonds permit the government to levy a nonlinear inflation tax and that such a tax may be better in terms of the Pareto criterion than a linear inflation tax.
A mixed graphical model for rhythmic parsing

A method is presented for the rhythmic parsing problem: Given a sequence of observed musical note onset times, we simultaneously estimate the corresponding notated rhythm and tempo process. A graphical model is developed that represents the evolution of tempo aud rhythm and relates these hidden quantities to an observable performance. The rhythm variables are discrete and the tempo and observation variables are continuous. We show how to compute the globally most likely configuration of the tempo and rhythm variables given an observation of note onset times. Preliminary experiments are presented on a small data set. A generalization to computing MAP estimates for arbitrary conditional Gaussian distributions is outlined.
Challenges in educational reform: An experiment on active learning in mathematics

This paper reports the results of an experiment designed to improve secondary school students’ ability to reason and argue using mathematics. A structured pedagogical intervention was created to foster a more active role of students in the classroom. The intervention was implemented with high fidelity and was internally valid. Surprisingly, students in the control group learned significantly more than those who received treatment.
Calibration of Computational Models With Categorical Parameters and Correlated Outputs via Bayesian Smoothing Spline ANOVA

It has become commonplace to use complex computer models to predict outcomes in regions where data do not exist. Typically these models need to be calibrated and validated using some experimental data, which often consists of multiple correlated outcomes. In addition, some of the model parameters may be categorical in nature, such as a pointer variable to alternate models (or submodels) for some of the physics of the system. Here, we present a general approach for calibration in such situations where an emulator of the computationally demanding models and a discrepancy term from the model to reality are represented within a Bayesian smoothing spline (BSS) ANOVA framework. The BSS-ANOVA framework has several advantages over the traditional Gaussian process, including ease of handling categorical inputs and correlated outputs, and improved computational efficiency. Finally, this framework is then applied to the problem that motivated its design; a calibration of a computational fluid dynamics (CFD) model of...
The structure of the D0-D4 bound state

Abstract We derive a set of equations for the wavefunction describing the marginal bound state of a single D0-brane with a single D4-brane. These are equations determining the vacuum of an N=8 Abelian gauge theory with a charged hypermultiplet. We then solve these equations for the most general possible zero-energy solution using a Taylor series. We find that there are an infinite number of such solutions of which only one must be normalizable. We explore the structure of a normalizable solution under the assumption of an asymptotic expansion. Even the leading terms in the asymptotic series, which should reflect the supergravity solution, are unusual. Through the Spin(5) flavor symmetry, the modes which are massive at long distance actually influence the leading behavior. Lastly, we show that the vacuum equations can quite remarkably be reduced to a single equation involving one unknown function. The resulting equation has a surprisingly simple and suggestive form.
Communication practices of coaches during mediator training: Addressing issues of knowledge and enactment

The purpose of this study was to describe how coaches of mediators-in-training manage interaction in role-play sessions and help trainees learn about mediation practices. Using a qualitative, discourse analytic approach, we examined role-played mediation sessions where thirteen professional mediators each provided coaching to two pairs of student trainees who had completed training in interest-based mediation (for a total of twenty-six sessions). We argue that the techniques we observed at crucial moments in mediation training seemed designed to improve trainees' understanding of the mediation process but offered limited help in teaching trainees how to enact the communication practices that are essential to mediation. We consider how the demands of giving advice and assessing communication behavior affect what coaches say to trainees in these circumstances.
Effects of baffle length on the performance of pipe insulation

Numerical results are presented for natural convection in a horizontal pipe insulation with radial baffles. It has been shown that radial baffles are effective in reducing convective heat losses from pipe insulation. The effectiveness in the reduction of heat loss depends on the length and orientation of the baffles. For the cases examined in this study, the baffles with a length of H/D = 0.5 give the best result. At Ra = 500, the flow and temperature fields become unstable for some pipe-baffles configurations. The averaged heat transfer rate, however, is still less when using baffles. 10 refs.
Magnetotransport studies of epitaxial Cr thin films

We report the results of transport measurements on epitaxial Cr thin films. The variation of TN (The Neel transition temperature) with respect to the film thickness is discussed in terms of the stress in the film. In addition, the temperature dependence of the magnetoresistance and Hall resistance for temperatures from 4 to 150 K are measured and discussed, with particular attention to the temperature dependence of the nonlinear portion of the Hall data.
Crystal engineering with 1,4-piperazine-2,5-diones

Experimental testing of a paradigm for the design and construction of functional crystalline solids based on an indane/piperazinedione/indane scaffold is summarized. In theory, molecular assembly is predetermined by incorporation of chemically and geometrically orthogonal intermolecular interactions. Application of the paradigm to the development of materials possessing liquid crystalline and nonlinear optical properties is presented.
Bis-pyranoside alkenes: Novel templates for the synthesis of adjacently linked tetrahydrofurans

Abstract Bis-pyranoside alkenes are used as templates for the convergent assembly of highly substituted, adjacently linked, tetrahydrofurans (THF's). The methodology centers on the stereoselective preparation of a bis-THF diol core structure.
A toy model for the AdS/CFT correspondence

We study the large-N gauged quantum mecchanics for a single hermitean matrix in the Harmonic oscillator potential well as a toy model for the AdS/CFT correspondence. We argue that the dual geometry should be a string in two dimensions with a curvature of stringy size. Even though the dual geometry is not weakly curved, one can still gain knowledge of the system from a detailed study of the open-closed string duality. We give a mapping between the basis of states made of traces (closed strings) and the eigenvalues of the matrix (D-brane picture) in terms of Schur polynomials. This is interpreted as an exact open-closed duality. We connect this model with a decoupling limit of = 4 SYM and the study of giant gravitons in AdS5 ? S5. We show that the two giant gravitons that expand along AdS5 and S5 can be interpreted in the matrix model as taking an eigenvalue from the Fermi sea and exciting it very much, or as making a hole in the Fermi sea respectively. This is similar to recent studies of the c = 1 string. This connection gives new insight on how to perform calculations for giant gravitons.
Alkene Hydrofunctionalization Using Hydroxamic Acids: A Radical-Mediated Approach to Alkene Hydration

A radical-mediated approach to alkene hydration is described. The present strategy capitalizes on the unique radical reactivity of hydroxamic acids, which are capable of functioning as both synthetically useful oxygen-centered radical species and suitable hydrogen atom-based donors. This reaction manifold has been applied to both alkene hydrations and tandem alkene-alkene carbocyclization processes.
Waves and circulation driven by oscillatory winds in an idealized ocean basin

Abstract We examine, via direct numerical integration, the transient and rectified response of a flat-bottomed barotropic ocean to a spatially localized oscillatory wind-stress pattern. These experiments exemplify in many respects the dynamics which drive the deep motion in recent eddy-resolving ocean circulation studies [e.g., Holland and Rhines (1980)], and may be contrasted with the results of Pedlosky (1965) and Veronis (1966) for spatially broad, time-dependent forcing. By considering doubly re-entrant (periodic) and closed basin geometries, the structure and magnitude of the induced circulation is shown to depend most critically on the form of the mean quasi-geostrophic contours (which are closed and blocked, respectively, in the periodic and basin geometries). In both situations, however, the forced primary wave field may be usefully understood by appeal to the radiation pattern of a time-periodic Green's function, and (in a basin) its image in the western boundary. The dynamics of the prograde and...
F-alkyliron(II) compounds

Abstract F-Alkyliron tetracarbonyl iodides are convenient sources of terminal vinyl iodides by a simple pyrolytic technique. The precursors to the F-alkyliron tetracarbonyl iodides, an F-alkyl iodide and iron pentacarbonyl, can be used to generate F-alkyl radicals capable, for example, of F-alkylating benzene in moderate yield. Mechanisms for these transformations are proposed.
The Short- and Long-Run Marginal Cost Curve: A Pedagogical Note.

A demonstration and explanation of short-run marginal costs that are lower than long-run marginal costs.
Is the Redshift Clustering of Long-Duration Gamma-Ray Bursts Significant?

The 26 long-duration gamma-ray bursts (GRBs) with known redshifts form a distinct cosmological set, selected differently than other cosmological probes such as quasars and galaxies. Since the progenitors are now believed to be connected with active star formation and since burst emission penetrates dust, one hope is that with a uniformly selected sample, the large-scale redshift distribution of GRBs can help constrain the star formation history of the universe. However, we show that strong observational biases in ground-based redshift discovery hamper a clean determination of the large-scale GRB rate and hence the connection of GRBs to the star formation history. We then focus on the properties of the small-scale (clustering) distribution of GRB redshifts. When corrected for heliocentric motion relative to the local Hubble flow, the observed redshifts appear to show a propensity for clustering: eight of 26 GRBs occurred within a recession velocity difference of 1000 km s-1 of another GRB. That is, four pairs of GRBs occurred within 30 h Myr in cosmic time, despite being causally separated on the sky. We investigate the significance of this clustering using a simulation that accounts for at least some of the strong observational and intrinsic biases in redshift discovery. Comparison of the numbers of close redshift pairs expected from the simulation with that observed shows no significant small-scale clustering excess in the present sample; however, the four close pairs occur in only about 20% of the simulated data sets (the precise significance of the clustering is dependent on the modeled biases). We conclude with some impetuses and suggestions for future precise GRB redshift measurements.
Synthesis of N-Acyl-N,O-Acetals from N-Aryl Amides and Acetals in the Presence of TMSOTf

Abstract Secondary amides undergo in situ silyl imidate formation mediated by TMSOTf and an amine base, followed by addition to acetal acceptors to provide N-acyl-N,O-acetals in good yields. An analogous, high-yielding reaction is observed with 2-mercaptothiazoline as the silyl imidate precursor. Competing reduction of the acetal to the corresponding methyl ether via transfer hydrogenation can be circumvented by the replacement of CY2NMe with 2,6-lutidine under otherwise identical reaction conditions.
Effect of Particle Size Distribution on Particle Dynamics and Blade Erosion in Axial Flow Turbines

This work presents the results of an investigation conducted to study the effect of coal ash particles size distribution on the particle dynamics, and the resulting blade erosion in axial flow gas turbines. The particle dynamics and their blade impacts are determined from a three dimensional trajectory analysis within the turbine blade passages. The particle rebound conditions and the blade material erosion characteristics are simulated using empirical equations, derived from experimental measurements. For the typical ash particle size distribution considered in this investigation, the results demonstrate that the size distribution has a significant influence on the blade erosion intensity and pattern.Copyright © 1990 by ASME
The Free Culture and 15M Movements in Spain: Composition, Social Networks and Synergies

This profile discusses the organization, goals and practices of the Spanish 15M movement. I argue that it developed as a complex, multi-layered ecosystem, mobilizing a new generation of citizens through the convergence of struggles over housing and the Free Culture and Digital Commons Movement (FCM), creating a common framework for action through social networks. Primarily in and through the actions in public squares, the 15M movement also constructed further layers of mobilization, incorporating the networks and skills of previous social movements (such as those mobilizing over inter alia education, health, alternative consumption) and connecting with previous generations who had mobilized over civil liberties in transition to democracy. Furthermore, I argue that links with the Free Culture Movement had a profound effect on the genealogy of 15M—in terms of its composition, agenda, framing and organizational logic. The methodology is based on case studies of both the FCM and 15M between December 2010 and ...
Bifurcations in a Mathieu equation with cubic nonlinearities

Abstract We investigate the nonlinear dynamics of the classical Mathieu equation to which is added a nonlinearity which is a general cubic in x, ẋ. We use a perturbation method (averaging) which is valid in the neighborhood of 2:1 resonance, and in the limit of small forcing and small nonlinearity. By comparing the predictions of first-order averaging with the results of numerical integration, we show that it is necessary to go to second-order averaging in order to obtain the correct qualitative behavior. Analysis of the resulting slow-flow equations is accomplished both analytically as well as by use of the software AUTO.
Menu-based natural language understanding

Menu-Based Natural Language Understanding is a new approach to building natural language interfaces. It retains the main goals of natural language systems: flexibility, expressive power, learnability and mnemonicity. However, it solves most of the problems inherent to conventional natural language systems. All queries are understood by the system, interface generation is much simpler, and less computing power is required. Many interfaces have been built using the menu-based natural language technology.
Assessing Racial Profiling

In this article I consider the evaluation of racial profiling in traffic stops from a combination of welfarist and non-welfarist considerations. I argue that benefits from profiling in terms of crime reduction have not been identified and that further, the harm to those who are innocent and stopped is potentially high. I then argue that profiling creates a clear injustice to innocent African Americans. Together, these claims make the assessment of profiling an example of decision making under ambiguity. I resolve the ambiguity with a Fairness Presumption which leads me to reject profiling in traffic stops as a public policy.
State-estimators for Chemical Reaction Networks of Feinberg-Horn-Jackson Zero Deficiency Type

This paper provides a necessary and sufficient condition for detectability for chemical reaction networks of the Feinberg-Horn-Jackson zero deficiency type. Under this condition, an explicit construction of globally convergent observers is obtained based on ISS techniques. The observers are easy to implement, and several robustness aspects are tested in numerical simulations.
A new algorithm for recognizing the unknot

The topological underpinnings are presented for a new algorithm which answers the question: “Is a given knot the unknot?” The algorithm uses the braid foliation technology of Bennequin and of Birman and Menasco. The approach is to consider the knot as a closed braid, and to use the fact that a knot is unknotted if and only if it is the boundary of a disc with a combinatorial foliation. The main problems which are solved in this paper are: how to systematically enumerate combinatorial braid foliations of a disc; how to verify whether a combinatorial foliation can be realized by an embedded disc; how to find a word in the the braid group whose conjugacy class represents the boundary of the embedded disc; how to check whether the given knot is isotopic to one of the enumerated examples; and finally, how to know when we can stop checking and be sure that our example is not the unknot. AMS Classification numbers Primary: 57M25, 57M50, 68Q15 Secondary: 57M15, 68U05
Optimal diagonal scaling for infinity-norm optimization

Abstract A solution is presented for the previously unsolved diagonally scaled multivariable infinity-norm optimization problem of minimizing ∥ D ( s )( A ( s ) + Ψ ( s ) X ( s )) D −1 ( s )∥ ∞ over the set of stable minimum-phase diagonal D ( s ) and stable X ( s ). This problem is of central importance in the synthesis of feedback control laws for robust stability and insensitivity in the presence of ‘structured’ plant uncertainty. The result facilitates the design of feedback controllers which optimize the ‘excess stability margin’ [3] (or, equivalently, the ‘structured singular value μ’ [4]) of diagonally perturbed feedback systems.
IMMIGRATION AND FIRM EXPANSION

Research generally focuses on how immigration affects native workers, while the impact of immigration on domestic firms is often overlooked. This paper addresses this important omission by examining whether firms respond to immigration by expanding their production activities within a city in order to utilize the abundant supply of low-skilled workers. Using data on immigration and the universe of establishments in U.S. cities, the results indicate that firms respond to immigration at the extensive margin by increasing the number of establishments. Not surprisingly, immigration has a more positive impact on the number of establishments that are small in size and in relatively mobile, low-skill intensive industries. Additional evidence indicates that immigration has little impact on employment within existing establishments, the intensive margin, or on the number of establishments in service industries which may expand simply due to immigrant consumption.
The albedo, size, and density of binary kuiper belt object (47171) 1999 TC36

We measured the system-integrated thermal emission of the binary Kuiper Belt object (47171 ) 1999 TC36, at wavelengths near 24 and 70 μm using the Spitzer Space Telescope. We fit these data and the visual magnitude using both the standard thermal model and thermophysical models. We find that the effective diameter of the binary is 405 km, with a range of 350-470 km, and the effective visible geometric albedo for the system is 0.079, with a range of 0.055-0.11. The binary orbit, magnitude contrast between the components, and system mass have been determined from HSTdata studied by Margot et al. Our effective diameter, combined with that system mass, indicates an average density for the objects of 0.5 g cm-3, with a range 0.3-0.8 g cm -3. This density is low compared to that of materials expected to be abundant in solid bodies in the trans-Neptunian region, requiring 50%-75% of the interior of (47171 ) 1999 TC36 be taken up by void space. This conclusion is not greatly affected if (47171)1999 TC36 is differentiated (in the sense of having either a rocky or just a nonporous core). If the primary is itself a binary, the average density of that (hypothetical) triple system would be in the range 0.4-1.l g cm -3, with a porosity in the range 15%-70%. © 2006. The American Astronomical Society. All rights reserved.
Hyperkalemia during human cardiopulmonary resuscitation: incidence and ramifications

Although hypokalemia has been reported after cardiac arrest and successful resuscitation, experimental data indicate that potassium is released from cells during ischemia. The purpose of this investigation was to study serum potassium concentration ([K+]) during closed chest cardiopulmonary resuscitation (CC-CPR) in humans. Twenty-two patients presenting to the emergency department (ED) in cardiopulmonary arrest had simultaneous measurement of central venous and arterial [K+] and blood gases during CC-CPR utilizing current advanced cardiac life support protocols and a pneumatic chest compressor and ventilator. Mean arterial and central venous [K+] were 5.0 +/- 1.3 and 5.6 +/- 2.9 mEq/L, respectively, (p greater than .05) with 7 patients having [K+] of greater than 6 mEq/L. Significant hyperkalemia does occur in some patients during cardiac arrest and CC-CPR. Because poor tissue perfusion during CC-CPR impairs exchange between the interstitial and intravascular compartments, increases in interstitial [K+] would be expected to be even greater. Interstitial hyperkalemia may play a role in the genesis of wide complex electromechanical dissociation (EMD) seen after prolonged cardiac arrest. Since calcium has long been known to be beneficial in the treatment of hyperkalemia-induced dysrhythmias, the success of calcium chloride in treating wide complex EMD may be on the basis of this phenomenon.
G-algebras, Twistings, and Equivalences of Graded Categories

Given \({\mathbb Z}\)-graded rings A and B, we ask when the graded module categories gr-A and gr-B are equivalent. Using \({\mathbb Z}\)-algebras, we relate the Morita-type results of Ahn-Marki and del Rio to the twisting systems introduced by Zhang, and prove, for example: TheoremIf A and B are \({\mathbb Z}\)-graded rings, then: (1) A is isomorphic to a Zhang twist of B if and only if the \({\mathbb Z}\)-algebras \(\overline{A} = \bigoplus_{i,j \in {\mathbb Z}} A_{j-i}\) and \(\overline{B} = \bigoplus_{i,j \in {\mathbb Z}} B_{j-i}\) are isomorphic. (2) If A and B are connected graded with A1 ≠ 0, then gr-A ≃ gr- B if and only if \(\overline{A}\) and \( \overline{B}\) are isomorphic. This simplifies and extends Zhang’s results.
Pure Red-Cell Aplasia

Pure red cell aplasia (PRCA) was first described by Kaznelson (1922) as an anemia due to an almost complete cessation of erythropoiesis, but without leukopenia or thrombocytopenia. This condition usually can be clearly distinguished from aplastic anemia in which low blood white cell and platelet concentrations accompany the anemia (Van Der Weyden and Firkin, 1972). In PRCA the bone marrow has an isolated absence of erythroblasts with normal granulocytopoiesis and megakaryocytopoiesis (DiGiacomo et al., 1966; Jacobs et al., 1959), whereas in aplastic anemia all three hematopoietic lineages are markedly reduced (Van Der Weyden and Firkin, 1972). In children PRCA has been called “chronic (congenital) hypoplastic anemia,” the Diamond-Blackfan anemia, or erythrogenesis imperfecta (Diamond and Blackfan, 1938; Gasser, 1957; Tsai and Levin, 1957). In adults it has been termed isolated aplastic anemia, aplastic crisis, erythroblastopenia, erythrophthisis, chronic erythrocytic hypoplasia, red cell aplastic anemia, or red cell agenesis (Gasser, 1957; Tsai and Levin, 1957). Although these cases could represent a variety of pathogenetic mechanisms they all have in common an isolated absence of marrow erythroblasts and are now considered together as cases of PRCA.
Regioselective conversion of alkynes to 4-substituted and 3,4-disubstituted isoxazoles using titanium-catalyzed multicomponent coupling reactions

Conditions have been developed for the regioselective synthesis of 4-substituted isoxazoles from terminal alkynes and 3,4-disubstituted isoxazoles from internal alkynes. The methodology involves a one-pot titanium-catalyzed multicomponent coupling reaction followed by simple hydroxylamine hydrochloride addition.
Use Of Oil And Gas Platforms As Habitat In Louisiana's Artificial Reef Program

ABSTRACT Louisiana's offshore oil and gas industry began in 1947 when the first well was drilled out of sight of land south of Terrebonne Parish, Louisiana. Today, over 3,900 offshore oil and gas platforms have been installed, supplying 25% of the United States' production of natural gas and approximately 13% of its oil. In addition to meeting the world's energy needs, these structures also form one of the world's most extensive defacto artificial reef systems. However, Federal regulations require that these structures be removed within 1 year after the mineral lease is terminated. Disposal of obsolete offshore oil and gas structures is not only a financial liability for private industry but can be a loss of productive marine habitat. To date (December, 1998) approximately 1700 rigs have been removed since 1973 from the Gulf of Mexico. In 1986 the Louisiana Fishing Enhancement Act was signed into law, in response to the National Fishing Enhancement Act, creating the Louisiana Artificial Reef Program. This program was designed to take advantage of fishing habitat opportunities offered by these obsolete platforms. Since the program's inception, 25 reef sites, utilizing the components (jackets and decks) of 75 obsolete platforms, have been created off Louisiana's coast. The use of obsolete oil and gas platforms in Louisiana has proved to be highly successful. Their large numbers, design, longevity, and stability have provided a number of advantages over the use of traditional artificial reef materials. The participating companies also save money by converting the structure into a reef rather than abandoning it onshore. They then are required to donate a portion of the savings to the state to run the artificial reef program. One disadvantage, however, is that the large size of these platforms restricts the distance from shore where they can be sited. To achieve the minimum clearance of 16 m over a submerged structure, as required by the New Orleans (8th) Coast Guard District regulations, the platforms must be placed in waters deeper than 30 m. Waters of this depth are found between 22 km and 115 km from shore on Louisiana's gently sloping continental shelf, making them almost inaccessible to many anglers. Funds generated by the program, however, can be used to develop reefs closer to shore if alternative low profile materials are used. Due to high maintenance costs of both the structure and aids to navigation, the increased liability exposure and the undetermined cost of removing the structure once it becomes a hazard to public safety and navigation, leaving the structures standing in place has thus far proved not to be a viable option in Louisiana.
On the Exact Complexity of Evaluating Quantified k -CNF

We relate the exponential complexities 2s(k)n of $\textsc {$k$-sat}$ and the exponential complexity $2^{s(\textsc {eval}(\mathrm {\varPi }_{2} 3\textsc {-cnf}))n}$ of $\textsc {eval}(\mathrm {\varPi }_{2} 3\textsc {-cnf})$ (the problem of evaluating quantified formulas of the form $\forall\vec{x} \exists\vec{y} \textsc {F}(\vec {x},\vec{y})$ where F is a 3-cnf in $\vec{x}$ variables and $\vec{y}$ variables) and show that s(ź) (the limit of s(k) as kźź) is at most $s(\textsc {eval}(\mathrm {\varPi }_{2} 3\textsc {-cnf}))$. Therefore, if we assume the Strong Exponential-Time Hypothesis, then there is no algorithm for $\textsc {eval}(\mathrm {\varPi }_{2} 3\textsc {-cnf})$ running in time 2cn with c<1. On the other hand, a nontrivial exponential-time algorithm for $\textsc {eval}(\mathrm {\varPi }_{2} 3\textsc {-cnf})$ would provide a $\textsc {$k$-sat}$ solver with better exponent than all current algorithms for sufficiently large k. We also show several syntactic restrictions of the evaluation problem $\textsc {eval}(\mathrm {\varPi }_{2} 3\textsc {-cnf})$ have nontrivial algorithms, and provide strong evidence that the hardest cases of $\textsc {eval}(\mathrm {\varPi }_{2} 3\textsc {-cnf})$ must have a mixture of clauses of two types: one universally quantified literal and two existentially quantified literals, or only existentially quantified literals. Moreover, the hardest cases must have at least nźo(n) universally quantified variables, and hence only o(n) existentially quantified variables. Our proofs involve the construction of efficient minimally unsatisfiable $\textsc {$k$-cnf}$s and the application of the Sparsification lemma.
Simulating economy-wide models to capture the transition from financial crisis to social crisis

The transition from Asian financial crisis into employment and income loss is analyzed in details by using a structural path analysis (SPA) and a price endogenous model of computable general equilibrium (CGE) type. Indonesia is taken as a case study. It is revealed that the damage in the real sector has ripple effects on the services sector, reducing the demand for workers of the professional rural and urban category, the growing middle class of the country. In turn, the overall income of most high urban household declines. The depressed manufacturing and construction sector gravely injures the companies' financial position. For some sectors, the indirect transmission of the effects is not insignificant. The large drop of employment in rural professionals suggests that the rural non-farm activities are likely to receive a recession contagion from the urban-based economy. This also implies that there is no alternative outlet in the rural areas for the urban middle class who lost their jobs. Very likely, some of them will end up working in the informal sector. The CGE simulation also suggests that the real wages have declined, especially in the urban areas. The per-capita consumption of all urban workers drops, the largest decline of which is for the urban medium type. In general, therefore, the relative position of the urban sector deteriorates more than that in the rural area. Hence, the country has to be prepared to face a massive increase in urban poverty, a fertile ground for internal conflicts and social discontent.
Invariant fields of symplectic and orthogonal groups

Abstract The projective orthogonal and symplectic groups POn(F) and PSpn(F) have a natural action on the F vector space V′=Mn(F)⊕⋯⊕Mn(F). Here we assume F is an infinite field of characteristic not 2. If we assume there is more than one summand in V′, then the invariant fields F(V′)POn and F(V′)PSpn are natural objects. They are, for example, the centers of generic algebras with the appropriate kind of involution. This paper considers the rationality properties of these fields, in the case 1, 2, or 4 are the highest powers of 2 that divide n. We derive rationality when n is odd, or when 2 is the highest power, and stable rationality when 4 is the highest power. In a companion paper joint with Tignol, we prove retract rationality when 8 is the highest power of 2 dividing n. Back in this paper, along the way, we consider two generic ways of forcing a Brauer class to be in the image of restriction.
Formation of early water oceans on rocky planets

Terrestrial planets, with silicate mantles and metallic cores, are likely to obtain water and carbon compounds during accretion. Here I examine the conditions that allow early formation of a surface water ocean (simultaneous with cooling to clement surface conditions), and the timeline of degassing the planetary interior into the atmosphere. The greatest fraction of a planet’s initial volatile budget is degassed into the atmosphere during the end of magma ocean solidification, leaving only a small fraction of the original volatiles to be released into the atmosphere through later volcanism. Rocky planets that accrete with water in their bulk mantle have two mechanisms for producing an early water ocean: First, if they accrete with at least 1 to 3 mass% of water in their bulk composition, liquid water may be extruded onto the planetary surface at the end of magma ocean solidification. Second, at initial water contents as low as 0.01 mass% or lower, during solidification a massive supercritical fluid and steam atmosphere is produced that collapses into a water ocean upon cooling. The low water contents required for this process indicate that rocky super-Earth exoplanets may be expected to commonly produce water oceans within tens to hundreds of millions of years of their last major accretionary impact, through collapse of their atmosphere.
Prediction of Peak Oxygen Consumption in Patients with Intermittent Claudication

Determination of peak oxygen consumption (VO2peak) is considered important for assessing a patient's functional capacity and for exercise prescription. However, the equipment necessary to obtain accurate determination of Vo2peak is not always available in clinical settings. The present study sought to develop an equation to estimate VO2peak in peripheral arterial occlusive disease (PAOD) patients with intermittent claudication and to determine independent predictors of VO2peak in this population. One hundred and fifty-seven patients with intermittent claudication were assigned to either a validation group (n = 105) or a cross-validation group (n = 52). Medical history, height, weight, body mass index (BMI), age, gender, smoking status, resting and postexercise ankle/brachial systolic pressure index (ABI), and time to maximal claudication pain and maximal heart rate from an incremental graded exercise test (GXT) were used as potential independent predictors of VO2peak. Time to onset of maximal claudication...
Tunable-chirp pulse compression in quasi-phase-matched second-harmonic generation

We demonstrate continuously tunable compensation of linear chirp on a first-harmonic pump pulse to produce a near-transform-limited second-harmonic output pulse through the use of a chirped, fanned, periodically poled lithium niobate quasi-phase-matching grating. Compensation of positive and negative chirps is possible through reversal of device orientation. The device is simple and monolithic and can be applied to compensation of a higher-order phase with minor modification.
Random walks with imperfect trapping in the decoupled-ring approximation

We investigate random walks on a lattice with imperfect traps. In one dimension, we perturbatively compute the survival probability by reducing the problem to a particle diffusing on a closed ring containing just one single trap. Numerical simulations reveal this solution, which is exact in the limit of perfect traps, to be remarkably robust with respect to a significant lowering of the trapping probability. We demonstrate that for randomly distributed traps, the long-time asymptotics of our result recovers the known stretched exponential decay. We also study an anisotropic three-dimensional version of our model. We discuss possible applications of some of our findings to the decay of excitons in semiconducting organic polymer materials, and emphasize the crucial influence of the spatial trap distribution on the kinetics.
Cluster Mass Functions in the Large and Small Magellanic Clouds: Fading and Size-of-Sample Effects

The properties of ~939 star clusters in the Large and Small Magellanic Clouds were determined from ground-based CCD images in UBVR passbands. The areal coverage was extensive, corresponding to 11.0 kpc2 in the LMC and 8.3 kpc2 in the SMC. After corrections for reddening, the colors and magnitudes of the clusters were converted to ages and masses, and the resulting mass distributions were searched for the effects of fading, evaporation, and size-of-sample bias. The data show a clear signature of cluster fading below the detection threshold. The initial cluster mass function (ICMF) was determined by fitting the mass and age distributions with cluster population models. These models suggest a new method to determine the ICMF that is nearly independent of fading or disruption and is based on the slope of a correlation between age and the maximum cluster mass in equally spaced intervals of log age. For a nearly uniform star formation rate, this correlation has a slope equal to 1/(α - 1) for an ICMF of dn(M)/dM ∝ M-α. We determine that α is between 2 and 2.4 for the LMC and SMC using this method plus another method in which models are fitted to the mass distribution integrated over age and to the age distribution integrated over mass. The maximum mass method also suggests that the cluster formation rate in the LMC age gap between 3 and 13 Gyr is about a factor of 10 below that in the period from 0.1 to 1 Gyr. The oldest clusters correspond in age and mass to halo globular clusters in the Milky Way. They do not fit the trends for lower mass clusters but appear to be a separate population that either had a very high star formation rate and became depleted by evaporation or formed with only high masses.
Instrumentation at the Los Alamos Critical Assembly Laboratory

A summary is presented of the various types of electronic instrumentation used at the Los Alamos Critical Assembly Laboratory. Also discussed is automatic data handling equipment as well as the nature of command and readout signals used on remote control critical assembly machines. Equipment is described for performing prompt neutron lifetime measurements by the Rossi-? method, pile oscillator technique, and the power fluctuation experiment.
On the Hodge structure of elliptically fibered Calabi-Yau threefolds

The Hodge numbers of generic elliptically fibered Calabi-Yau threefolds over toric base surfaces fill out the “shield” structure previously identified by Kreuzer and Skarke. The connectivity structure of these spaces and bounds on the Hodge numbers are illuminated by considerations from F-theory and the minimal model program. In particular, there is a rigorous bound on the Hodge number h 21 ≤ 491 for any elliptically fibered Calabi-Yau threefold. The threefolds with the largest known Hodge numbers are associated with a sequence of blow-ups of toric bases beginning with the Hirzebruch surface $ {\mathbb{F}_{{12}}} $ and ending with the toric base for the F-theory model with largest known gauge group.
Organosilicon rings: Structures and strain energies

Geometries, strain energies, and electronic structures for 23 organosilicon compounds have been determined. The species studies were those for which silicon successively replaced carbon in cyclopropane, bicyclobutane, and (1.1.1)propellane and in propane, cyclobutane, and bicyclo(1.1.1)pentane. Wave functions constructed from the recently developed compact effective core potentials and using a split-valence, d-polarized basis set were employed. Accurate strain energies, validated by extensive comparison with existing experimental data and ab initio calculations, were obtained from a series of homodesmic reactions. When the compounds investigated are displayed in a periodic table format (increasing number of silicon replacements down a column, increasing number of fused rings across rows) many useful interrelationships and bonding patterns manifest themselves. In spite of their considerable complexity in structure and properties, it proves possible to understand them in terms of electronegativity arguments and a simple two-orbital, three-atom, molecular orbital model.
Secure computation with information leaking to an adversary

Assume that Alice is running a program P on a RAM, and an adversary Bob would like to get some information about the input or output of the program. At each time, during the execution of P, Bob is able to see the addresses of the memory cells involved in the instruction which is executed and the name of the instruction. In addition to this, at certain times, Bob can even see the contents of all of the memory cells involved in the instruction. We will call a time when this happens a compromised time. Bob can choose the compromised times in an adaptive way, that is, immediately before the instruction at time t is executed, Bob, using all of the information at his disposal, can decide whether time t will be compromised or not. The only restriction on his choice is, that among m consecutive instructions there can be at most e m whose time is compromised, where e>0 is a small constant. We show that if m= c⌊ log n ⌋, where c>0 is a large constant, then for each program P, using n memory cells and time T=O(poly(n)), Alice can construct a functionally equivalent program P', such that the probability that Bob gets any nontrivial information about the input of P is negligible, and the time and space requirements of P' grows, compared to P, only by a factor of poly(log n). We assume that the program P' gets its input in an encoded form, namely each input bit b is encoded by a random 0,1-sequence of length m whose parity is b. The output bits must be encoded by P' in a similar way.As part of the proof of the result described above we also construct for all positive integers m, and for all boolean circuits C of size n a functionally equivalent circuit C' of size O(n poly(m)) with the following properties. Assume that an adversary can observe each bit going through the wires of the circuit C' independently with a probability of e, where e>0 is a small constant, and each input/output bit of C is encoded by m input/output bits of C' the same way as described above for RAMs. Then, such an adversary, while observing C', can get any information about the input/output of the circuit C only with a probability of ne-cm, where c>0 is a constant.
STRAIN‐GAGING EARTH PENETRATORS TO PROVIDE DYNAMIC FORCE DATA

The method presented for mounting strain gages inside earth penetrators gives valid strain-time data during earth entry. In order to maintain axial and circumferential alignment of the strain gages inside the penetrator, a fixture is a necessity. The data obtained from the first test appear valid and indicates a higher degree of bending than had been expected. The data will be used to obtain force-time histories for use with analytical models. The second penetrator will be used to do a repeat of the first test in order to determine the repeatability of the data. Future testing using the same instrumentation will seek to determine the effects of targets of various hardnesses, varying impact velocities, angle of attack and angle of impact.
The misguided debate over NGO participation at the WTO

Whether private parties and NGOs should participate in the WTO system has recently become one of the most contentious issues in trade law and policy. However, this debate proceeds from the implicit--but mistaken--assumption that these entities currently do not participate in the system. While, as a formal matter, WTO 'legislative' and dispute resolution systems are open only to state actors, in fact private parties already participate extensively in WTO processes. Through discussion of several WTO disputes, including the Kodak-Fuji dispute, this paper demonstrates how the current debate substantially understates the considerable roles that NGOs already play in disputes submitted to the WTO. The claims here are largely positive and descriptive, rather than normative. By identifying and clarifying the roles that private parties currently play, I hope to close the increasing gulf between academic debate and WTO practice, and move the debate over NGO participation to a more fruitful series of inquiries. To this end, I argue that the controversy over NGO participation at the WTO can be understood as a particular instantiation of a larger debate over the roles of non-state actors in the international legal system. Copyright 1998 by Oxford University Press.
Relationship between auroral substorms and the occurrence of terrestrial kilometric radiation

The correlation between magnetospheric substorms as inferred from the AE(11) index and the occurrence of terrestrial kilometric radiation (TKR) is examined. It is found that AE and TKR are well correlated when observations are made from above the 15-03 hr local time zone and are rather poorly correlated over the 03-15 hr zone. High-resolution dynamic spectra obtained during periods of isolated substorms indicate that low-intensity, high-frequency TKR commences at about the same time as the substorm phase. The substorm expansion phase corresponds to a rapid intensification and bandwidth increase of TKR. When combined with previous results, these new observations imply that many TKR events begin at low altitudes and high frequencies (about 400-500 kHz) and spread to higher altitudes and lower frequencies as the substorm expands.