cssi/SciSciGPT-SciSciNet huggingface dataset:
Comparing Absentee and Precinct Voters: Voting on Direct Legislation

This paper addresses issues related to how absentee voters actually cast their ballots on propositions. If the liberalization of absentee laws changed either the composition or behavior of the electorate, then the outcome of the election may be affected. This paper tests whether the electoral behavior of absentee and precinct voters differs in regards to voting on propositions. The analysis is based on a sample of actual absentee and precinct voter ballots drawn from the approximately three million ballots cast in Los Angeles county for the 1992 general election. The analysis uses a nested model of voter participation and is estimated using the weighted exogenous sampling maximum likelihood method. We find that precinct and absentee voters do differ on both the propositions on which they cast votes and in their propensity to vote “Yes” for a proposition. For example, absentees appear to vote on fewer bonds and initiatives than do precinct voters. They also vote on fewer propositions dealing with state taxes, food taxes, and property taxes. In addition, given that a voter casts a valid vote, the propensity for absentee voters to vote “Yes” is higher on initiatives and propositions related to education, welfare, and health care than it is for precinct voters.
The number of objects in the original asteroid belt

Abstract Using the limited collisional evolution of Ceres and Vesta as constraints for the number of objects in the asteroid belt it is found that a moderate mass depletion by a factor of 3.6 occurred after the end of the accretion period. To model the angular momentum evolution a “particle-in-a-box” method is used which takes into account the size distribution of the actual belt and the loss of angular momentum by ejecta escaping preferentially in the prograde direction. It also provides a value of 0.26 for the fraction of leftover impact energy available for further mechanical work after a collision, which is higher than the values used by other authors for simulations. In a belt with these properties the survival during the Solar System age for objects with the dimensions of Vesta is granted, but for asteroids ≈ 300 km in diameter the survival probability is a strong function of the region where the object moves.
LPD communication when the warden does not know when

Unlike standard security methods (e.g. encryption), low probability of detection (LPD) communication does not merely protect the information contained in a transmission from unauthorized access, but prevents the detection of a transmission in the first place. In this work we study the impact of secretly pre-arranging the time of communication. We prove that if Alice has AWGN channels to Bob and the warden, and if she and Bob can choose a single $n$ symbol period slot out of $T(n)$ such slots, keeping the selection secret from the warden (and, thus, forcing him to monitor all $T(n)$ slots), then Alice can reliably transmit $\mathcal{O}(\min\{\sqrt{n\log T(n)},n\})$ bits to Bob while keeping the warden's detector ineffective. The result indicates that only an additional $\log T(n)$ secret bits need to be exchanged between Alice and Bob prior to communication to produce a multiplicative gain of $\sqrt{\log T(n)}$ in the amount of transmitted covert information.
Total pancreatectomy for pancreatic adenocarcinoma: evaluation of morbidity and long-term survival.

Objective:To analyze relative perioperative and long-term outcomes of patients undergoing total pancreatectomy versus pancreaticoduodenectomy.Background:The role of total pancreatectomy has historically been limited due to concerns over increased morbidity, mortality, and perceived worse long-term o
Efficient synthesis of p-bis-(chlorodifluoromethyl)benzene

Selective, high yield partial fluorination of p-bis-(trichloromethyl)benzene to p-bis-(chlorodifluoromethyl)benzene has been accomplished by warming a slurry of the p-bis-(trichloromethyl)benzene in anhydrous HF which also contains a small quantity of inert solvent, such as 1,2-dichloroethane.
Traffic assignment in communication satellites

A high capacity communication satellite interconnects scores of ground stations simultaneously. Under the Satellite-Switched/Time Division Multiple Access (SS/TDMA) system, each channel of the satellite is allocated to a pair of ground stations for a certain time period, after which the whole set of allocations (called a switch) is changed simultaneously. The problem we address is to minimize the time length of the entire sequence of switches, subject to a limit on the number of switches. We formulate this as a 3-index bottleneck-sum assignment problem, and solve it by a heuristic that obtains consistently better results than earlier methods based on different formulations.
Spiral-pattern formation in Rayleigh-Bénard convection.

We present a numerical study of the spontaneous formation of spiral patterns in Rayleigh-B\'enard convection in non-Boussinesq fluids. We solve a generalized two-dimensional Swift-Hohenberg equation that includes a quadratic nonlinearity and coupling to mean flow. We show that this model predicts in quantitative detail many of the features observed experimentally in studies of Rayleigh-B\'enard convection in ${\mathrm{CO}}_{2}$ gas. In particular, we study the appearance and stability of a rotating spiral state obtained during the transition from an ordered hexagonal state to a roll state.
Image restoration-based template matching with application to motion estimation

In this paper, we investigate the relationship between the image restoration and the template matching problems. A new formulation of template matching is presented. According to this formulation the relationship between image restoration and template matching is captured by the observation that the restored template can be used to ascertain its location. As a consequence, the duality between image restoration and template matching is established. An alternative approach is also presented to provide the interpretation of template matching as a special case of blurred image restoration. This approach is based on the observation that template matching can be viewed as image restoration of the degraded version of an unknown image blurred by a linear point spread function -- the template. It is shown that, unlike image restoration, all second order statistics required for the implementation of linear minimum mean-square error (LMMSE) template matching can be easily estimated. The linear minimum mean-square error (LMMSE) template matching is subsequently applied to block-matching motion estimation from degraded image sequences. Our experimental results indicate: First, that LMMSE template matching is superior to traditional block-matching. Second, that there exist certain applications, for example multichannel image sequence restoration, that greatly benefit from LMMSE-based template matching.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
How do galaxies get their gas

Not the way one might have thought. In hydrodynamic simulations of galaxy formation, some gas follows the traditionally envisioned route, shock heating to the halo virial temperature before cooling to the much lower temperature of the neutral ISM. But most gas enters galaxies without ever heating close to the virial temperature, gaining thermal energy from weak shocks and adiabatic compression, and radiating it just as quickly. This “cold mode” accretion is channeled along filaments, while the conventional, “hot mode” accretion is quasi-spherical. Cold mode accretion dominates high redshift growth by a substantial factor, while at z < 1 the overall accretion rate declines and hot mode accretion has greater relative importance. The decline of the cosmic star formation rate at low z is driven largely by geometry, as the typical cross section of filaments begins to exceed that of the galaxies at their intersections.
Disk enumeration on the quintic 3-fold

Holomorphic disk invariants with boundary in the real Lagrangian of a quintic 3-fold are calculated by localization and proven mirror transforms. A careful discussion of the underlying virtual intersection theory is included. The generating function for the disk invariants is shown to satisfy an extension of the Picard-Fuchs differential equations associated to the mirror quintic. The Ooguri-Vafa multiple cover formula is used to define virtually enumerative disk invariants. The results may also be viewed as providing a virtual enumeration of real rational curves on the quintic.
An efficient multi-vehicle multi-criteria mission planning and control system for autonomous underwater vehicles

In their study, Tavana and Bourgeois (2010) proposed a multi-criteria decision analysis model that considered dynamic and episodic phenomenon on the surface of the ocean and provided specific navigation plans. They showed that the transect for an autonomous underwater vehicle (AUV) includes not only the desired horizontal path, but also the depth range that the vehicle will operate in. They argued that the current models should be extended to include considerations that change vertically, that is, with different ocean depths. They also suggested expansion of the current models to cooperative teams of AUVs and showed that working together will allow underwater vehicles to complete tasks that could not be completed by a single vehicle. This study extends their model by: reducing the number of judgements required to generate the navigation scores within the decision region; considering ocean depth and finding the navigation scores for the ocean surface and interior; and developing a model which derives an optimal allocation of multiple vehicles to various locations within the decision region. The proposed framework is an efficient multi-vehicle multi-criteria mission planning and control system that considers ocean phenomenon on the surface and in the interior and provides an optimal allocation of vehicles with respect to the stated objective and subjective mission goals.
Toxicity Profiling of Engineered Nanomaterials via Multivariate Dose Response Surface Modeling

New generation in vitro high-throughput screening (HTS) assays for the assessment of engineered nanomaterials provide an opportunity to learn how these particles interact at the cellular level, particularly in relation to injury pathways. These types of assays are often characterized by small sample sizes, high measurement error and high dimensionality, as multiple cytotoxicity outcomes are measured across an array of doses and durations of exposure. In this paper we propose a probability model for the toxicity profiling of engineered nanomaterials. A hierarchical structure is used to account for the multivariate nature of the data by modeling dependence between outcomes and thereby combining information across cytotoxicity pathways. In this framework we are able to provide a flexible surface-response model that provides inference and generalizations of various classical risk assessment parameters. We discuss applications of this model to data on eight nanoparticles evaluated in relation to four cytotoxicity parameters.
Proof of a conjecture on permutation polynomials over finite fields

Let k be a positive integer and S 2 k = x + x 4 + ? + x 4 2 k - 1 ? F 2 x . It was recently conjectured that x + S 2 k 4 2 k + S 2 k 4 k + 3 is a permutation polynomial of F 4 3 k . In this note, the conjecture is confirmed and a generalization is obtained.
Higher education enrollment: The interaction of labor market conditions, curriculum, and selectivity

Abstract A number of recent studies have shown that conditions in the labor market for college graduates (LMCG) influence higher education enrollment. However, they have not considered how a college's curriculum and selectivity may affect the sensitivity of its enrollment to fluctuations in the LMCG. To examine this interaction, a model of enrollment demand was developed and its parameters were estimated from 1965–1981 data on a set of 64 independent colleges in Iowa and Illinois. The results show that colleges with an emphasis on traditional arts and sciences tend to have greater enrollment growth when the LMCG is improving, colleges with an emphasis on occupational fields tend to have greater enrollment growth when the LMCG is deteriorating.
Computational design of hypervelocity launchers

The Sandia Hypervelocity Launcher (HVL) uses impact techniques on a two-stage light-gas gun to launch flier plates to velocities in excess of 10 km/s. An important problem in designing successful third stage techniques for impact launching fliers to such velocities is detailed understanding of the interior ballistic performance of the third stage. This is crucial for preventing melt and fracture of the flier plates during the extraordinary accelerations that they undergo (accelerations on the order of 10{sup 9} g are typical on the HVL). We seek to optimize HVL launch conditions in order to achieve two major goals: first, to maximize the potential launch velocity for a given flier, and second, to allow different flier configurations. One tool that we can apply in studying HVL performance is the use of multi-dimensional wave propagation codes. We have used such codes, particularly the Sandia Eulerian code CTH, to study a variety of interior ballistics issues related to gun performance and launcher development for almost ten years. Recently this work has culminated in a major contribution to HVL design, namely the capability to launch ``chunk`` fliers. `Me initial phases of design development were solely devoted to CTH computations that studied potential designs, identifiedmore » problems, and posed possible solutions for launching chunk fliers on the HVL. Our computations sufficiently narrowed the design space to the point that systematic experimental progress was possible. Our first experiment resulted in the successful launch of an intact 0.33 gram titanium alloy chunk flier to a velocity of 10.2 km/s. The thickness to diameter ratio of this flier was approximately 0.5.« less
Null Trajectories and Bending of Light in Charged Black Holes with Quintessence

We have studied null geodesics of the charged black hole surrounded by quintessence. Quintessence is a candidate for dark energy and is represented by a scalar field. Here, we have done a detailed study of the photon trajectories. The exact solutions for the trajectories are obtained in terms of the Jacobi-elliptic integrals for all possible energy and angular momentum of the photons. We have also studied the bending angle using the Rindler and Ishak method.
Algorithmic proofs of two theorems of Stafford

Two classical results of Stafford say that every (left) ideal of the n-th Weyl algebra A"n can be generated by two elements, and every holonomic A"n-module is cyclic, i.e. generated by one element. We modify Stafford's original proofs to make the algorithmic computation of these generators possible.
On stochastic games with additive reward and transition structure

In this paper, we introduce a new class of two-person stochastic games with nice properties. For games in this class, the payoffs as well as the transitions in each state consist of a part which depends only on the action of the first player and a part dependent only on the action of the second player. For the zero-sum games in this class, we prove that the orderfield property holds in the infinite-horizon case and that there exist optimal pure stationary strategies for the discounted as well as the undiscounted payoff criterion. For both criteria also, finite algorithms are given to solve the game. An example shows that, for nonzero sum games in this class, there are not necessarily pure stationary equilibria. But, if such a game possesses a stationary equilibrium point, then there also exists a stationary equilibrium point which uses in each state at most two pure actions for each player.
A model for selecting short-term tests of carcinogenicity

A theoretical model is presented that selects among available short term tests of carcinogenicity and then classifies chemicals on the basis of the results. The model is simplified in ignoring the potency of various carcinogens but does take account of the social cost of falsely classifying a chemical as a carcinogen as well as the social cost of falsely classifying a chemical as a noncarcinogen. If some of the currently available short-term tests, separately or in sets, are capable of classifying chemicals with even moderate accuracy, this framework would serve to improve the regulation of suspect carcinogens.
GROK-LAB: Generating Real On-chip Knowledge for Intra-cluster Delays Using Timing Extraction

Timing Extraction identifies the delay of fine-grained components within an FPGA. From these computed delays, the delay of any path can be calculated. Moreover, a comparison of the fine-grained delays allows a detailed understanding of the amount and type of process variation that exists in the FPGA. To obtain these delays, Timing Extraction measures, using only resources already available in the FPGA, the delay of a small subset of the total paths in the FPGA. We apply Timing Extraction to the Logic Array Block (LAB) on an Altera Cyclone III FPGA to obtain a view of the delay down to near-individual LUT SRAM cell granularity, characterizing components with delays on the order of tens to a few hundred picoseconds with a resolution of ±3.2ps, matching the expected error bounds. This information reveals that the 65nm process used has, on average, random variation of σ μ =4.0p with components having an average maximum spread of 83ps. Timing Extraction also shows that as VDD decreases from 1.2V to 0.9V in a Cyclone IV 60nm FPGA, paths slow down, and variation increases from σ μ =4.3p to σ μ =5.8p, a clear indication that lowering VDD magnifies the impact of random variation.
The contribution of foreign direct investment to clean energy use, carbon emissions and economic growth

The paper investigates the contributions of foreign direct investment (FDI) net inflows to clean energy use, carbon emissions, and economic growth. The paper employs cointegration tests to examine a long-run equilibrium relationship among the variables and fixed effects models to examine the magnitude of FDI contributions to the other variables. The paper analyzes panel data of 19 nations of the G20 from 1971 to 2009. The test results indicate that FDI has played an important role in economic growth for the G20 whereas it limits its impact on an increase in CO2 emissions in the economies. The research finds no compelling evidence of FDI link with clean energy use. Given the results, the paper discusses FDI's potential role in achieving green growth goals.
Accommodation responses to stimuli in cone contrast space.

The aim was to identify the cone contributions and pathways for reflex accommodation. Twelve illumination conditions were used to test specified locations in cone-contrast space. Accommodation was monitored continuously in a Badal optometer while the grating stimulus (2.2 c/d sine-wave; 0.27 modulation) moved sinusoidally (0.195 Hz) towards and away from the eye from a mean position of 2.00 D (±1.00 D). Mean accommodation level and dynamic gain and phase at 0.195 Hz were calculated. Mean accommodation level varied significantly when the long- and middle-wavelength cone contrast ratio was altered in both the luminance and chromatic quadrants of cone-contrast space. This experiment indicates that L- and M-cones contribute to luminance and chromatic signals that produce the accommodation response, most likely through magno-cellular and parvo-cellular pathways, respectively. The L:M cone weighting to the luminance pathway that mediates accommodation is 1.63:1. The amplitude and direction of the response depends on changes in chromatic contrast and luminance contrast signals that result from longitudinal chromatic aberration and defocus of the image.
Property attribution and the projection postulate in relativistic quantum theory

Abstract State-vectors resulting from collapse along the forward light cone from a measurement interaction can be used for the attribution of both local and non-local properties.
Corporate Income Taxation and Signaling

A signaling model is developed to investigate the consequences of corporate income taxation in the presence of adverse selection in the equity market. The model obtains a unique, informationally constrained efficient equilibrium in which a better quality firm retains more inside equity, and, as in the complete information case, only profitable firms are supported The corporate income tax affects signaling costs and the profitability of projects. Numerical experiments with exponential utility functions find that the inside equity position of a better quality firm increases as the corporate income tax rate rises. This reaction is, however, insensitive to the tax rate change due to the risk sharing with the government, which leads to the interesting result that the corporate income tax only incurs a lower welfare cost than the lump sum tax with the same tax revenue.
AVERAGE-DISTANCE PROBLEM FOR PARAMETERIZED CURVES

We consider approximating a measure by a parameterized curve subject to length penalization. That is for a given finite compactly supported measure μ , with \hbox{$\mu\left(\R^d\right)>0$} for p ≥ 1 and λ > 0 we consider the functional \begin{equation} E(\gm) = \int_{\R^d} d(x, \Gamma_\gamma)^p {\rm d}\mu(x) + \lambda \,\text{Length}(\gamma) \end{equation} E ( γ ) = ∫ R d d ( x, Γ γ ) p d μ ( x ) + λ Length ( γ ) where γ : I → ℝ d , I is an interval in ℝ, Γ γ = γ ( I ), and d ( x, Γ γ ) is the distance of x to Γ γ . The problem is closely related to the average-distance problem, where the admissible class are the connected sets of finite Hausdorff measure ℋ 1 , and to (regularized) principal curves studied in statistics. We obtain regularity of minimizers in the form of estimates on the total curvature of the minimizers. We prove that for measures μ supported in two dimensions the minimizing curve is injective if p ≥ 2 or if μ has bounded density. This establishes that the minimization over parameterized curves is equivalent to minimizing over embedded curves and thus confirms that the problem has a geometric interpretation.
Pathologic findings and outcomes for octogenarians presenting with uterine malignancy

Abstract Objective. We evaluated prognostic, demographic and outcome data for patients >80 years old with uterine cancer (UC). Methods. A retrospective review of clinical records was performed. Categorical data were compared using Fisher's exact test and Kaplan-Meier for survival data. Results. Sixty-five patients were identified with a mean age of 84 and BMI 27. Sixty-five percent of patients had medical co-morbidities. Forty-two (65%) were Stage I; 10 (15%) were Stage II; 8 (12%) were Stage III; and 5 (8%) were Stage IV. Stage I patients included those identified via hysterectomy with lymph nodes (LND) (30) or clinical impression (12). Comparing clinically Stage I UC to those with LND, the clinical group was older (86 vs. 83; p =0.01) and tended to have more medical co-morbidity (89% vs. 63%; p =0.14). Two-year overall survival (OS) among unstaged vs. staged patients was 62% vs. 77%; p =0.11. Among staged patients with Stage I UC, 21 (70%) met high intermediate risk (HIR) criteria per GOG 99 and 90% received no adjuvant therapy. Three patients (16%) recurred with 1 (5%) locoregional recurrence. Two-year OS is 77%. Conclusion. Elderly patients with UC have features associated with extrauterine spread. Both clinically and surgically staged Stage I patients had excellent OS at 2 years despite no adjuvant therapy. Prevalent medical co-morbidities may impact survival more than recurrence risk. The 23% recurrence rate among HIR patients in GOG 99 was not observed in our data, suggesting that observation for elderly Stage I patients is acceptable.
Spatial Analyticity of Solutions to Integrable Systems. I. The KdV Case

We are concerned with the Cauchy problem for the KdV equation for nonsmooth locally integrable initial profiles q's which are, in a certain sense, essentially bounded from below and q(x) = O(e−cxϵ ), x → + ∞, with some positive c and ϵ. Using the inverse scattering transform, we show that the KdV flow turns such initial data into a function which is (1) meromorphic (in the space variable) on the whole complex plane if ϵ > 1/2, (2) meromorphic on a strip around the real line if ϵ = 1/2, and (3) Gevrey regular if ϵ <1/2. Note that q's need not have any decay or pattern of behavior at − ∞.
NUMERICAL INVESTIGATION OF SEPARATED TRANSONIC TURBULENT FLOWS WITH A MULTIPLE-TIME-SCALE TURBULENCE MODEL

Numerical investigation of transonic flows separated by streamline curvature and shock wave-boundary layer interaction is presented. The free-stream Much numbers considered are 0.4, 0.5, 0.6, 0.7, 0.8, 0.825, 0.85, 0.875, 0.90, and 0.925. In the numerical method, the conservation of mass equation is replaced by a pressure correction equation for compressible flows and thus the equation is solved for incremental pressure rather than density. The turbulence is described by a multiple-time-scale turbulence model supplemented with a near-wall turbulence model. The present numerical results show that there exists a reversed flow region at all free-stream Mach numbers considered whereas various k-e turbulence models fail to predict such a reversed flow region at low free-Stream Mach numbers. The numerical results also show that the size of the reversed flow region grows extensively due to the shock wave-turbulent boundary layer interaction as the free-stream Mach number is increased. These numerical results sho...
Unsteady piping forces caused by hot water discharge from suddenly opened safety/relief valves

Abstract Various fluid transients in nuclear pressure vessels create the possibility of liquid discharge from safety/relief valves designed for steam release. Piping systems which carry the flow from safety/relief valves to an appropriate discharge environment are designed to withstand the unsteady reaction forces associated with steam flows. If liquid discharge occurs, the piping system may be subject to different unsteady reaction forces. This study provides a means of estimating discharge rates for saturated and subcooled water and resulting pipe forces, for the limiting case of a suddenly opened valve. It was found that pipe forces caused by the moving shock are about the same for either steam or water discharge. Pipe forces caused by a moving steam-water/air interface during water discharge may exceed those forces caused by the steam-air interface resulting from steam discharge. It was determined that water discharge would result in a longer opening time for a piston-type valve. It is therefore expected that with realistic estimates of valve opening time, the magnitude of water discharge forces will be approximately the same as steam discharge piping forces.
Anomalous spreading in a system of coupled Fisher-KPP equations

Abstract In this article, we report on the curious phenomena of anomalous spreading in a system of coupled Fisher–KPP equations. When a single parameter is set to zero, the system consists of two uncoupled Fisher–KPP equations which give rise to traveling fronts propagating with the unique, minimal KPP speed. When the coupling parameter is nonzero various behaviors can be observed. Anomalous spreading occurs when one component of the system spreads at a speed significantly faster in the coupled system than it does in isolation, while the speed of the second component remains unchanged. We study these anomalous spreading speeds and show that they arise due to poles of the pointwise Green’s function corresponding to the linearization about the unstable homogeneous state. These poles lead to anomalous spreading in the linearized system and come in two varieties—one that persists and leads to anomalous spreading for the nonlinear system and one that does not. We describe mechanisms leading to these two behaviors and prove that one class of poles are irrelevant as far as nonlinear wavespeed selection is concerned. Finally, we show that the same mechanism can give rise to anomalous spreading even when the slower component does not spread.
Synthesis and structure–activity relationships of thiotetronic acid analogues of thiolactomycin

3-Acetyl analogues of thiolactomycin, a thiotetronic acid natural product, were synthesized and profiled against livestock pathogens. Some analogues showed improved activity over thiolactomycin against Staphylococcus aureus and comparable activity against Pasteurella multocida. Several semisynthetically modified analogues of thiolactomycin showed no improvement in activity over thiolactomycin.
A 2-categorical extension of the Reshetikhin--Turaev theory

We concretely construct a 2-categorically extended TQFT that extends the Reshetikhin–Turaev TQFT to cobordisms with corners. The source category will be a well chosen 2-category of decorated cobordisms with corners and the target bicategory will be the Kapranov–Voevodsky 2-vector spaces.
Chronic negative circumstances and compulsive buying: consumer vulnerability after a natural disaster

This research is composed of two cross-sectional studies that examine the lingering emotional distress associated with a natural disaster and extend the understanding of its impact on consumption attitudes and behaviors when victims are confronted with additional challenges. The first study examines victims' (n = 426) depression-induced impulsive and compulsive buying after Hurricane Katrina; the second investigates how the recession has exacerbated victims' (n = 191) lingering stress and depressive states, and the effects of these on consumption. These historical events provide a unique opportunity to extend the life event and disaster research and to examine the relationship between negative events and specific consumer behaviors. Results indicate that, years later, compulsive buying has not subsided, and the adversity brought on by the recession appears to have contributed to extended depressive states. Implications for marketers and public policy makers are discussed, as they relate to how vulnerable ...
Vibration Control of Nonlinear Rotating Beam Using Piezoelectric Actuator and Sliding Mode Approach

In this research, we develop a general methodology for the vibration control of a nonlinear rotating beam. The dynamic model of a rotating Euler-Bernoulli beam integrated with a piezoelectric actua...
Volume of myocardium perfused by coronary artery branches as estimated from 3D micro-CT images of rat hearts

Average myocardial perfusion is remarkably consistent throughout the heart wall under resting conditions and the velocity of blood flow is fairly reproducible from artery to artery. Based on these observations, and the fact that flow through an artery is the product of arterial cross-sectional area and blood flow velocity, we would expect the volume of myocardium perfused to be proportional to the cross-sectional area of the coronary artery perfusing that volume of myocardium. This relationship has been confirmed by others in pigs, dogs and humans. To test the body size-dependence of this relationship we used the hearts from rats, 3 through 25 weeks of age. The coronary arteries were infused with radiopaque microfil polymer and the hearts scanned in a micro- CT scanner. Using these 3D images we measured the volume of myocardium and the arterial cross-sectional area of the artery that perfused that volume of myocardium. The average constant of proportionality was found to be 0.15 +/- 0.08 cm3/mm2. Our data showed no statistically different estimates of the constant of proportionality in the rat hearts of different ages nor between the left and right coronary arteries. This constant is smaller than that observed in large animals and humans, but this difference is consistent with the body mass-dependence on metabolic rate.© (2000) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Morse theory on Banach manifolds

Let ƒ be a C2 function on a C2 Banach manifold. A critical point x of ƒ is said to be weakly nondegenerate if there exists a neighborhood U of x and a hyperbolic linear isomorphism Lx: Tx(M) → Tx(M) such that in the coordinate system of U, dƒx + v(Lxv) > 0 if v ≠ 0. Lx defines an index invariantly, and it is shown that this is an extension of the usual definition of nondegeneracy and index. It is shown that this weaker nondegeneracy can be used in place of the stronger nondegeneracy conditions in Morse theory. In addition, sufficient conditions for the critical points of variational problems to be weakly nondegenerate are given.
Self-enforcing arrangements in African political economy

Abstract Self-enforcing arrangements are crucial to the study of African political econmy. The weakness of formal governance in much of Africa makes understanding informal institutions of cooperation particularly important. I consider the application of self-enforcing arrangements, like those described by the Ostroms, to the problems of violence and social heterogeneity that plague Africa.
Alkenylimmonium salts as dienophiles in Diels-Alder cycloadditions with high reactivity and stereoselectivity☆

Abstract Alkenylimmonium salts, such as the substituted vinylpyridinium salts, 6, 7, 12 , and 16 , are easily prepared and are very reactive dienophiles in Diels-Alder cycloadditions.
User satisfaction in competitive sponsored search

We present a model of competition between web search algorithms, and study the impact of such competition on user welfare. In our model, search providers compete for customers by strategically selecting which search results to display in response to user queries. Customers, in turn, have private preferences over search results and will tend to use search engines that are more likely to display pages satisfying their demands. Our main question is whether competition between search engines increases the overall welfare of the users (i.e., the likelihood that a user finds a page of interest). When search engines derive utility only from customers to whom they show relevant results, we show that they differentiate their results, and every equilibrium of the resulting game achieves at least half of the welfare that could be obtained by a social planner. This bound also applies whenever the likelihood of selecting a given engine is a convex function of the probability that a user's demand will be satisfied, which includes natural Markovian models of user behavior. On the other hand, when search engines derive utility from all customers (independent of search result relevance) and the customer demand functions are not convex, there are instances in which the (unique) equilibrium involves no differentiation between engines and a high degree of randomness in search results. This can degrade social welfare by a factor of Ω(√{NUMPAGES}) relative to the social optimum, where NUMPAGES is the number of webpages. These bad equilibria persist even when search engines can extract only small (but non-zero) expected revenue from dissatisfied users, and much higher revenue from satisfied ones.
Grain Boundary Structural Transformations Induced by Solute Segregation

Abstract The influence of solute segregation on the structure of small angle [001] twist boundaries was studied in Fe-rich Fe-Au alloys which were in the form of thin bicrystal specimens. It was shown that Au segregation at the boundary causes a change from the single dislocation array seen in pure Fe to two dislocation arrays with different Burgers vectors. In the Au-poor regions of the boundary, the dislocation structure is a 〈110〉 square network with Burgers vector, b = a 2 〈111〉 , similar to that seen in pure Fe, while in the Au-rich regions of the boundary, the dislocation structure is a 〈100〉 square network with b = a〈100〉 . Analytical electron microscopy and Rutherford backscattering spectroscopy were used to obtain information on the distribution of the Au in the vicinity of the boundary. The observation of a change in dislocation structure is considered evidence for the occurrence of a structural transformation induced by solute segregation. The influence on the structural transformation of variables such as composition and boundary misorientation angle was studied, and the results are presented in the form of a grain boundary phase diagram, with each dislocation network considered as a two dimensionally periodic phase with a small extent along the direction normal to the interface.
Semistability-based robust and optimal control design for network systems

In this paper, we present a new Linear-Quadratic Semistabilizers (LQS) theory for linear network systems. This new semistable ℌ 2 control framework is developed to address the robust and optimal semistable control issues of network systems while preserving network topology subject to white noise. Two new notions of semistabilizability and semicontrollability are introduced as a means to connecting semistability with the Lyapunov equation based technique.With these new notions, we first develop a semistable ℌ 2 control theory for network systems by exploiting the properties of semistability. A new series of necessary and sufficient conditions for semistability of the closed-loop system have been derived in terms of the Lyapunov equation. Based on these results, we propose a constrained optimization technique to solve the semistable ℌ 2 network-topology-preserving control design for network systems. Then optimization analysis and the development of numerical algorithms for the obtained constrained optimization problem are conducted. We establish the existence of optimal solutions for the obtained nonconvex optimization problem. Next, we propose a swarm optimization based numerical algorithm towards efficiently solving this nonconvex, nonlinear optimization problem due to the strong resemblance between swarm behaviors in nature and the notion of semistability. Finally, several numerical examples will be provided to illustrate the effectiveness of the proposed method.
Dynamic SEM Wear Studies of Tungsten Carbide Cermets

Dynamic friction and wear experiments were conducted in a scanning electron microscope. The wear behavior of pure tungsten carbide and composite with 6 and 15 weight percent cobalt binder was examinded. Etching of the binder was done to selectively determine the role of the binder in the wear process. Dynamic experiments were conducted as the WC and bonded WC cermet surfaces were transversed by a 50 micron radiused diamond stylus. These studies show that the predominant wear process in WC is fracture initiated by plastic deformation. The wear of the etched cermets is similar to pure WC. The presence of the cobalt binder reduces both friction and wear. The cementing action of the cobalt reduces granular separation and promotes a dense polished layer because of its low shear strength film-forming properties. The wear debris generated from unetched surface is approximately the same composition as the bulk. Presented as an American Society of Lubrication Engineers paper at the ASLE/ASME Lubrication Conference...
Highly enantio- and diastereoselective organocatalytic cascade aza-Michael–Michael reactions: a direct method for the synthesis of trisubstituted chiral pyrrolidines

An unprecedented highly enantio- and diastereoselective cascade aza-Michael–Michael reaction of α,β-unsaturated aldehydes with trans-γ-Ts protected amino α,β-unsaturated ester has been developed; the simple and practical process, efficiently catalyzed by chiral diphenylprolinol TMS ether, serves as a powerful access to highly functionalized trisubstituted chiral pyrrolidines.
A review of the decomposition method and some recent results for nonlinear equations

Abstract The decomposition method can be an effective procedure for solution of nonlinear and/or stochastic continous-time dynamical systems without usual restrictive assumptions. This paper is intended as a convenient tutorial review of the method. 1
Unifying simulatability definitions in cryptographic systems under different timing assumptions

The cryptographic concept of simulatability has become a salient technique for faithfully analyzing and proving security properties of arbitrary cryptographic protocols. We investigate the relationship between simulatability in synchronous and asynchronous frameworks by means of the formal models of Pfitzmann et. al., which are seminal in using this concept in order to bridge the gap between the formal-methods and the cryptographic community. We show that the synchronous model can be seen as a special case of the asynchronous one with respect to simulatability, i.e., we present an embedding between both models that we show to preserve simulatability. We show that this result allows for carrying over lemmas and theorems that rely on simulatability from the asynchronous model to its synchronous counterpart without any additional work. Hence future work can concentrate on the more general asynchronous case, without having to neglect the analysis of synchronous protocols.
Tubular Nanostructured Materials for Bioapplications

Tubular nanomaterials possess hollow structures as well as high aspect ratios. In addition to their unique physical and chemical properties induced by their nanoscale dimensions, their inner voids and outer surfaces make them ideal candidates for a number of biomedical applications. In this work, three types of tubular nanomaterials including carbon nanotubes, hematite nanotubes, and maghemite nanotubes, were synthesized by different chemical techniques. Their structural and crystalline properties were characterized. For potential bioapplications of tubular nanomaterials, experimental investigations were carried out to demonstrate the feasibility of using carbon nanotubes, hematite nanotubes, and maghemite nanotubes in glucose sensing, neuronal growth, and drug delivery, respectively. Preliminary results show the promise of tubular nanomaterials in future biomedical applications.
Degenerate four-wave mixing in atomic ytterbium

We have performed degenerate four-wave mixing experiments with cryogenically cooled atomic ytterbium. We use buffer-gas cooling to prepare high optical density samples at a temperature of 5 K, cold enough to resolve the different isotopes and hyperfine transitions. We observe four-wave mixing with cross-polarized pump and probe beams. The four-wave mixing is strongly enhanced when the laser is closely detuned from the S01(F=1/2)→P11(F′=1/2) transition of the Yb171 (I=1/2) isotope.
Superflares from magnetars revealing the GRB central engine

Long-duration gamma-ray bursts (GRBs) may be powered by the rotational energy of a millisecond magnetar. I argue that the GRB-driving magnetars lie at the high end of the distribution of magnetic field strengths of magnetars. The field of GRB magnetars decays on time-scale of hundreds of years and can power soft gamma-ray repeater (SGR)-like flares up to ∼100 times more powerful than the 2004 event of SGR 1806–20. A few of these flares per year may have been observed by the Burst and Transient Source Experiment (BATSE) and classified as short-duration GRBs. Association of one of these superflares with a nearby dL≲ 250 Mpc galaxy and the discovery of a, coincident in space, 100-yr-old GRB afterglow (observed in the radio) will be the characteristic signature of the magnetar model for GRBs.
Supergravity and Superstrings

Over the last decade, theorists have been searching hard for a unified quantum field theory of physical interactions with or without gravitation. The “standard” SU_3 x SU_2 x U_1 theory has three independent coupling constants and numerous dimensionless parameters determining the mass ratios, the weak coupling matrix, etc. The number of sets of Higgs bosons and the representation to which they belong appear arbitrary. The theory cries out to be embedded in a bigger and more nearly unified theory. The fact that the coupling constants appear to come together somewhere between 10^(15) GeV and the Planck mass of ~ 2 x 10^(19) GeV suggests a unified Yang-Mills theory, for example with SU5 and three fermion families (fermions in 5 + 10). However, such a theory, with one coupling constant, still has numerous dimensionless parameters and arbitrary Higgs boson behavior
Regular pattern formation through the retraction and pinch-off of edges during solid-state dewetting of patterned single crystal films

We report the formation of regular patterns of metal lines via solid-state dewetting of lithographically patterned single-crystal Ni(110) films with square and cross shapes. During the solid-state dewetting, valleys develop behind retracting edges and eventually lead to pinch-off and formation of lines. Mass accumulation at convex pattern corners also leads to formation of lines. We show that the size of large-scale patterns and surface-energy anisotropy affect the smaller-scale dewetted structures in a deterministic way.
Turbulent Heat Transfer in Large Aspect Channels

Abstract : Heat transfer in turbulent flow was measured in a rectangular channel with a width of 0.254 m and a flow depth of 0.0254 m. Correlations between the Nusselt and Reynolds numbers are given for a range of 3020 Re 22360. A Prandtl number range of 9.90 or = Pr or = 12.28 for water was used in the tests. The results are compared with those of other investigations and show that some well-known correlations underpredict the heat transfer by about 35%.
Solar Cycle Effects on the Near-Earth Plasmas and Space Systems

Abstract : Solar physicists have predicted that the upcoming maximum of solar activity, scheduled to occur near 1990, might be the most extreme ever recorded. Based on the observed rate of increase in solar activity starting with the most recent minimum in 1986 the upcoming solar maximum will be the most severe of those which have occurred during the space age. Correlations between solar activity and disturbances in the near-earth magnetospheric and ionospheric plasmas which adversely affect communications and space systems are well documented. The implementation of larger, more complex (and perhaps more susceptible) space systems over the last decade, has led to concern and speculation about the expected performance and survivability of these space systems over the next decade. Unfortunately, because of the complex and sometimes indirect interactions between the sun and the plasma environment in near-earth space, very few firm quantitative predictions can be made regarding the expected effects of an extreme solar maximum on the near-earth environment or on the complex systems operating in that environment. A number of qualitative predictions can be made with high confidence. Satellite communications links in the VHF/UHF range will suffer signal fades more often and with greater severity. Short wave and airline communications will be sporadically disrupted. Satellites will experience electrical charging of their surface and internal dielectric components, resulting in disruptive electrostatic discharges and micro- electronic devices on satellites will experience upsets more often.