cssi/SciSciGPT-SciSciNet huggingface dataset:
The influence of quantitative tumor volume measurements on local control in advanced head and neck cancer using concomitant boost accelerated superfractionated irradiation

Purpose: Current methods to clinically define head and neck tumor bulk are qualitative and imprecise. Although the American Joint Committee on Cancer (AJCC) staging system is important for this purpose, limitations exist. This study will investigate the prognostic value of computed tomography (CT) derived tumor volume measurements in comparison to AJCC stage and other significant variables. Materials and Methods: Seventy-six patients with advanced head and neck squamous cell carcinoma were treated with concomitant boost accelerated sunerfractionated irradiation. Doses ranged from 68.4-73.8 Gv (median 70.2 Gy). Good quality pretherapy CT scans were available in 51 patie&. Total tumor volumk (TTV) estimates were derived from these scans using digital integration of primary tumor and metastatic lymphadenopathy. Actuarial and multivariate statistical techniques were applied to analyze local control. Results: Thirty-six-month local control was 63%. TTV ranged from 5-l% cm3 (median 35 cm3) for all cases, 5-142 cm3 (median 17 cm3) for those controlled, and 16-l% cm3 (median 47 cm3) for local failures. There was a significant increase in failures above 35 cm’. Univariate analysis found that ‘PI’V, T-stage, Nstage, and primary site were each significant prognostic variables. Local control for TTV 535 cm3 was 92% at 36 months vs. 34% for ‘M’V >35 cm3 (p = 0.0001). Multivariate analysis, however, found that TTV, primary site, and sex were important as independent variables; T and N stage were not independently significant unless TTV was removed from the model. Conclusions: This study demonstrates the prognostic significance of TTV in advanced carcinoma of the head and neck. This variable appears to be a more predictive than AJCC clinical stage. Quantitative tumor volume measurements may prove to be a useful parameter in future analyses of head and neck cancer. Tumor volume, Head and neck neoplasms, Radiotherapy, Prognosis, Local control, Altered fractionation, Staging, Concomitant boost, Radiation dosage.
Selective Preparation of 4-(Bromo or Iodo)-2,5-dimethoxybenzonitrile and 2-(Bromo or Iodo)-3,6-dimethoxybenzonitrile from 2,5-Dimethoxybenzaldehyde

Abstract By use of appropriate reactions and sequence of steps, 2,5-dimethoxybenzaldehyde can be converted either to 4-(bromo or iodo)-2,5-dimethoxybenzonitrile or 2-(bromo or iodo)-3,6-dimethoxybenzonitrile.
Uncertain availability, spatial location and regulation: An application to the airline industry

This paper presents an analysis of industries characterized by both uncertain availability and spatial location of the product. The analyis is applied to the US airline industry and is used to analyze the differential effect of price regulation on different markets and firms. From this analysis we obtain insights into which firms and markets may have benefited most from the deregulation of the industry in 1978. Previous works on the regulation of the airline industry implicitly assume that markets have the same demand structure. If airline services are of homogeneous quality, men we do not expect the unregulated solution to depend on demand structures. If on the other hand airline services vary in their quality component, then different markets may have different equilibrium price-quality combinations depending on the characteristics of demand. This paper explores the implication of different demand structures on the impact of (de)regulation.
Symbolic computer vector analysis

Abstract A MACSYMA program is described which performs symbolic vector algebra and vector calculus. The program can combine and simplify symbolic expressions including dot products and cross products, together with the gradient, divergence, curl and Laplacian operators. The distribution of these operators over sums or products is under user control, as are various other expansions, including expansion into components in any specific orthogonal curvilinear co-ordinate system. There is also a capability for deriving the scalar or vector potential of a vector field. Examples include derivation of the partial differential equations describing fluid flow and magnetohydrodynamics, for 12 different classic orthogonal curvilinear co-ordinate systems.
Alumina Thin Films as Optical Waveguides

Amorphous AI2O3, fabricated by reactive rf magnetron sputtering, has been evaluated as a planar waveguide material. The microstructure and optical properties of planar waveguides were examined as a function of deposition (substrate temperature, O2 flow rate) and annealing conditions. X-ray and electron diffraction verified that as-deposited films were amorphous for substrate temperatures up to 500°C and for a wide range of O2 flow rates. This amorphous phase was stable through anneals up to 800°C, but crystallized to “y-Al2O3 at 1000°C and to α-Al2O3 at 1200°C. The amorphous films had transmission windows that extended from 200 nm to 7 (Am with an average refractive index of 1.65 and reproducible losses as low as ∼1 dB/cm at 632.8 nm. The refractive index increased with substrate temperature, but was independent of O2 flow rate. The losses decreased with substrate temperature and increased as a function of O2 flow rate. As a final check on the amorphous structure, Cr-doped films were prepared by codeposition. Fluoresence was detected only in annealed crystalline films.
Decarbonylative cross-coupling of cyclic anhydrides: introducing stereochemistry at an sp3 carbon in the cross-coupling event.

Treatment of cyclic anhydrides with stoichiometric amounts of nickel−neocuproine complex generates alkylcarboxylato−nickelalactones upon extrusion of CO. These metalacycles undergo cross-coupling with arylzinc reagents. The generated CO is sequestered in situ by a nickel−dppb complex. The overall sequence effects a secondary sp3(electrophile)−sp2(nucleophile) cross-coupling and allows for control of stereochemistry during the bond-forming event.
A neural model of how the brain computes heading from optic flow in realistic scenes

Visually-based navigation is a key competence during spatial cognition. Animals avoid obstacles and approach goals in novel cluttered environments using optic flow to compute heading with respect to the environment. Most navigation models try either explain data, or to demonstrate navigational competence in real-world environments without regard to behavioral and neural substrates. The current article develops a model that does both. The ViSTARS neural model describes interactions among neurons in the primate magnocellular pathway, including V1, MT(+), and MSTd. Model outputs are quantitatively similar to human heading data in response to complex natural scenes. The model estimates heading to within 1.5 degrees in random dot or photo-realistically rendered scenes, and within 3 degrees in video streams from driving in real-world environments. Simulated rotations of less than 1 degrees /s do not affect heading estimates, but faster simulated rotation rates do, as in humans. The model is part of a larger navigational system that identifies and tracks objects while navigating in cluttered environments.
Generalized primitive elements of a free group

We study endomorphisms of a free group of finite rank by means of their action on specific sets of elements. In particular, we prove that every endomorphism of the free group of rank 2 which preserves an automorphic orbit (i.e., acts "like an automorphism" on one particular orbit), is itself an automorphism. Then, we consider special elements, defined by means of homological properties of the corresponding one-relator group. These elements are shown to make "nice" orbits under the action of the automorphism group of a free group, and also to have other interesting properties that bring together group theory, topology, and homological algebra.
Polynomiality of some hook-length statistics

We prove a conjecture of Okada giving an exact formula for a certain statistic for hook-lengths of partitions: $$\frac{1}{n!} \sum_{\lambda \vdash n} f_{\lambda}^2 \sum_{u \in \lambda} \prod_{i=1}^{r}\bigl(h_u^2 - i^2\bigr) = \frac{1}{2(r+1)^2} \binom{2r}{r}\binom{2r+2}{ r+1} \prod_{j=0}^{r} (n-j),$$ where f λ is the number of standard Young tableaux of shape λ and h u is the hook length of the square u of the Young diagram of λ. We also obtain other similar formulas.
Statistical verification of conformance to geometric tolerance

Abstract Modern coordinate measurement machines have provided industry with new tools for inspecting complex parts. The paper develops statistical procedures that complement these inspection methods, and it ties the conformance problem into the hypothesis testing formalism of conventional statistics. Also, the paper suggests strategies for efficient sampling of the part surface, and an implementation of the usual decision-theoretic formulation of the tradeoff between false acceptance and false rejection of part geometries. These ideas are illustrated through the analysis of real and simulated data for perfect and imperfect cylinders.
DinnerWare: why playing with food should be encouraged

DinnerWare is an exploration of eating as a medium for computation and aesthetic expression. It consists of a dining service electronically equipped to react to the properties of the food that it holds and respond to a user's eating gestures.
Effect of Fin Thickness on Flow and Heat Transfer in Multi-Louvered Fins

High-resolution time-dependent numerical simulations are used to investigate the effect of thickness ratio on fluid flow and heat transfer performance in multi-louvered fins. Results for three fin thickness ratios, two louver angles, and a fin pitch to louver pitch ratio of one are reported for Reynolds number ranging from 50 to 1200. Thickness ratio is found to have a significant effect on flow efficiency, especially in geometries with small louver angles. For small louver angles, increasing thickness to louver pitch ratio from 0.05 to 0.15, decreases the flow efficiency by as much as 35–40%. As expected, increasing thickness ratio increases total pressure drop, most of which results from an increase in form drag. Heat transfer coefficient, on the other hand, is not influenced strongly by the thickness ratio. The increase in flow acceleration and local Reynolds number with increase in thickness ratio, on one hand, is offset by low flow efficiencies and recirculation zones on the other. As a consequence, some heat transfer degradation is found at low Reynolds numbers, however the degradation diminishes as the Reynolds number increases beyond 300. In general, larger thickness ratios lead to a lower ratio of j/f.© 2002 ASME
Twisted Sectors and Chern-Simons Terms in M-Theory Orbifolds

It is shown that the twisted sector spectrum, as well as the associated Chern–Simons interactions, can be determined on M-theory orbifold fixed planes that do not admit gravitational anomalies. This is demonstrated for the seven-planes arising within the context of an explicit R6 × S1/Z2 × T4/Z2 orbifold, although the results are completely general. Local anomaly cancellation in this context is shown to require fractional anomaly data that can only arise from a twisted sector on the seven-planes, thus determining the twisted spectrum up to a small ambiguity. These results open the door to the construction of arbitrary M-theory orbifolds, including those containing fixed four-planes which are of phenomenological interest.
A convenient chemoselective semihydrogenation of acetylenes using homogeneous catalysis

Abstract Acetylenes and some dienes are rapidly reduced to olefins by a combination of acetic acid and a silicon hydride in the presence of a Pd(0) catalyst.
Metal ion complexation by a new, highly sterically hindered, bowl-shaped carboxylate ligand

A carboxylate encapsulated by arene groups arranged in a bowl-like shape coordinates to Fe(II), Co(II) and Cu(II) to form mononuclear complexes with atypical structures enforced by the extreme steric demands of the ligand.
Metastable gravitons and infinite volume extra dimensions

Abstract We address the issue of whether extra dimensions could have an infinite volume and yet reproduce the effects of observable four-dimensional gravity on a brane. There is no normalizable zero-mode graviton in this case, nevertheless correct Newton's law can be obtained by exchanging bulk gravitons. This can be interpreted as an exchange of a single metastable 4D graviton. Such theories have remarkable phenomenological signatures since the evolution of the Universe becomes high-dimensional at very large scales. Furthermore, the bulk supersymmetry in the infinite volume limit might be preserved while being completely broken on a brane. This gives rise to a possibility of controlling the value of the bulk cosmological constant. Unfortunately, these theories have difficulties in reproducing certain predictions of Einstein's theory related to relativistic sources. This is due to the van Dam–Veltman–Zakharov discontinuity in the propagator of a massive graviton. This suggests that all theories in which contributions to effective 4D gravity come predominantly from the bulk graviton exchange should encounter serious phenomenological difficulties.
Neural network control of a class of nonlinear systems with actuator saturation

A neural net (NN)-based actuator saturation compensation scheme for the nonlinear systems in Brunovsky canonical form is presented. The scheme that leads to stability, command following, and disturbance rejection is rigorously proved and verified using a general "pendulum type" and a robot manipulator dynamical systems. Online weights tuning law, the overall closed-loop system performance, and the boundedness of the NN weights are derived and guaranteed based on Lyapunov approach. The actuator saturation is assumed to be unknown and the saturation compensator is inserted into a feedforward path. Simulation results indicate that the proposed scheme can effectively compensate for the saturation nonlinearity in the presence of system uncertainty.
Chlorine initiated photooxidation studies of hydrochlorofluorocarbons (HCFCs) and hydrofluorocarbons (HFCs): Results for HCFC‐22 (CHClF2); HFC‐41 (CH3F); HCFC‐124 (CClFHCF3); HFC‐125 (CF3CHF2); HFC‐134a (CF3CH2F); HCFC‐142b (CClF2CH3); and HFC‐152a (CHF2CH3)

Data on the tropospheric degradation of proposed substitutes for ozone depleting CFCs were obtained by conducting photochemical oxidation studies of HCFCs and HFCs using long path Fourier transform infrared spectroscopy. The hydrogen abstraction reactions were initiated using Cl radicals rather than OH radicals because of the rather unreactive nature of the compounds. The experimental product yields at T = 25 ± 3°C and 700 Torr of dry air were: CHClF2 (1.11 ± 0.06 C(O)F2); CClFHCF3 (1.00 ± 0.04 CF3C(O)F); CF3CHF2 (1.09 ± 0.05 C(O)F2); CClF2CH3 (0.98 ± 0.03 C(O)F2); CHF2CH3 (1.00 ± 0.05 C(O)F2); CF3CH2F (0.16 ± 0.03 CF3CF(O), and 0.83 ± 0.22 HFC(O)), where all standard deviations are 2σ. For each compound, the critical step in determining the oxidation products was the decomposition of a halogenated alkoxy radical. For HCFC-22 and HCFC-124, the major alkoxy radical decomposition route was Cl elimination. The HFC-125 product data were consistent with CC cleavage of a two carbon alkoxy radical as the major decomposition route whereas both CC cleavage and H abstraction by O2 were significant contributors to the decomposition of the HFC-134a alkoxy radical. Secondary Cl reactions in the HCFC-142b and HFC-152a experiments prevented an unambiguous determination of the decomposition modes; the data are consistent with both CC bond scission and Cl reactions with halogenated aldehydes producing the oxidation product C(O)F2. With the exception of the HFC-134a and HFC-125 data, the proposed mechanisms can account for the major oxidation products. For HFC-134a and HFC-125, a number of product bands could not be identified. The bands are likely due to products from reactions involving the CF3O2 radical. © John Wiley & Sons, Inc.
Suicidal behavior in children and adolescents.

Although many of the principles and approaches toward suicidal youth are similar to those used with suicidal adults, some key differences exist. This article highlights the main differences between adolescent and adult suicidal behavior. Screening and assessment, treatment, and legal implications related to this population are also explored. Language: en
Hand and foot length in Prader-Willi syndrome

Small hands and feet (acromicria) are often cited as manifestations in the Prader-Willi syndrome (PWS), but it has been our experience that these are not universal findings. To address this issue, we obtained longitudinal and cross-sectional data, retrospectively and prospectively, including height, hand length, and foot length, on 56 patients with PWS who are followed in the multidisciplinary PWS clinic at the University of Connecticut Health Center. Hand and foot lengths were plotted using two published sets of normative data. In addition, height age was calculated on each measurement of stature so that the corresponding hand and foot measurements could be compared to those expected for height, rather than age, as many PWS individuals are short. Foot length was proportionately smaller than hand length in all individuals; this difference was more striking in females. By age 12 years, almost all individuals had a foot length less than 25th centile for chronological age and less than 50th centile for height age. Female hand length was also less than 25th centile for chronological by age 12 years and less than 50th centile for height age in almost all cases. Male hand length data appeared to fall more within the normal range until adulthood, although fewer data were available. Black individuals with PWS had relatively larger hands and feet than their Caucasian counterparts. Many people with PWS had hand and foot lengths which fell within the normal range, particularly those under the age of 12 years and those whose height was greater than 50th centile for age.(ABSTRACT TRUNCATED AT 250 WORDS)
The Local structure of anomaly inflow

Anomaly cancellation for M-theory five-branes requires the introduction of a ``bump-form'' which smoothes out the five-brane source. We discuss the physical origin of this bump-form in the simpler case of axion strings in 3 + 1 dimensions and construct it in terms of the radial profile of the fermion zero modes. Our treatment allows for a clearer understanding of the role played by covariant rather than consistent anomalies when anomalies are canceled by inflow from the bulk. We briefly discuss the generalization of these results to five-brane anomalies in M-theory.
Interpolating between topologies: Casimir energies☆

Abstract A set of models is considered which, in a certain sense, interpolates between 1+1 free quantum field theories on topologically distinct backgrounds. The intermediate models may be termed free quantum field theories, though they are certainly not local. Their ground state energies are computed and shown to be finite. The possible relevance to changing spacetime topologies is discussed.
Limitations of Local Filters of Lipschitz and Monotone Functions

We study local filters for two properties of functions of the form f : {0,1}d → R: the Lipschitz property and monotonicity. A local filter with additive error a is a randomized algorithm that is given black-box access to a function f and a query point x in the domain of f. It outputs a value F(x) such that (i) the reconstructed functionF(x) satisfies the property (in our case, is Lipschitz or monotone) and (ii) if the input function f satisfies the property, then for every point x in the domain (with high constant probability) the reconstructed value F(x) differs from f(x) by at most a. Local filters were introduced by Saks and Seshadhri [2010]. The relaxed definition we study is due to Bhattacharyya et al. [2012], except that we further relax it by allowing additive error. Local filters for Lipschitz and monotone functions have applications to areas such as data privacy.We show that every local filter for Lipschitz or monotone functions runs in time exponential in the dimension d, even when the filter is allowed significant additive error. Prior lower bounds (for local filters with no additive error, that is, with a=0) applied only to a more restrictive class of filters, for example, nonadaptive filters. To prove our lower bounds, we construct families of hard functions and show that lookups of a local filter on these functions are captured by a combinatorial object that we call a c-connector. Then we present a lower bound on the maximum outdegree of a c-connector and show that it implies the desired bounds on the running time of local filters. Our lower bounds, in particular, imply the same bound on the running time for a class of privacy mechanisms.
An elementary proof that random Fibonacci sequences grow exponentially

Abstract We consider random Fibonacci sequences given by x n + 1 = ± β x n + x n − 1 . Viswanath [Divakar Viswanath, Random Fibonacci sequences and the number 1.13198824…, Math. Comp. 69 (231) (2000) 1131–1155, MR MR1654010 (2000j:15040)] following Furstenberg [Harry Furstenberg, Noncommuting random products, Trans. Amer. Math. Soc. 108 (1963) 377–428, MR MR0163345 (29 #648)] showed that when β = 1 , lim n → ∞ | x n | 1 / n = 1.13 … , but his proof involves the use of floating point computer calculations. We give a completely elementary proof that 1.23375 ⩾ ( E ( | x n | ) ) 1 / n ⩾ 1.12095 where E ( | x n | ) is the expected value for the absolute value of the nth term in a random Fibonacci sequence. We compute this expected value using recurrence relations which bound the sum of all possible nth terms for such sequences. In addition, we give upper and lower bounds for the second moment of the | x n | . Finally, we consider the conjecture of Embree and Trefethen [Mark Embree, Lloyd N. Trefethen, Growth and decay of random Fibonacci sequences, R. Soc. Lond. Proc. Ser. A Math. Phys. Eng. Sci. 455 (1987) (1999) 2471–2485, MR MR1807827 (2001i:11098)], derived using computational calculations, that for values of β 0.702585 such sequences decay. We show that as β decreases, the critical value where growth can change to decay is in fact 1 / 2 .
Insight into the scalar mesons from a lattice calculation

Abstract We study the possibility that the light scalar mesons are q 2 q 2 states rather than q q . We perform a lattice QCD calculation of pseudoscalar meson scattering amplitudes, ignoring quark loops and quark annihilation, and find indications that for sufficiently heavy quarks there is a stable four-quark bound state with J PC =0 ++ and non-exotic flavor quantum numbers.
Interstellar grains—the 75th anniversary

The year of 2005 marks the 75th anniversary since Trumpler (1930) provided the first definitive proof of interstellar grains by demonstrating the existence of general absorption and reddening of starlight in the galactic plane. This article reviews our progressive understanding of the nature of interstellar dust.
First-Principles Calculations of PuO2±x

The electronic structure of PuO2± x was studied using first-principles quantum mechanics, realized with the self-interaction corrected local spin density method. In the stoichiometric PuO2 compound, Pu occurs in the Pu(IV) oxidation state, corresponding to a localized f4 shell. If oxygen is introduced onto the octahedral interstitial site, the nearby Pu atoms turn into Pu(V) (f3) by transferring electrons to the oxygen. Oxygen vacancies cause Pu(III) (f5) to form by taking up electrons released by oxygen. At T = 0, the PuO2 compound is stable with respect to free oxygen, but the delicate energy balance suggests the possible deterioration of the material during long-term storage.
Are Audit Program Plans Risk‐Adjusted?

Prior archival and experimental studies provide conflicting results regarding the extent to which audit program plans are responsive to client risks, as prescribed by the Audit Risk Model. The purpose of this study is to corroborate and extend archival research on this issue by considering a broader set of client risks and incorporating a number of methodological improvements. Data were gathered on risk assessments and evidential plans in the accounts receivable area from the working papers of 74 randomly selected manufacturing clients (42 general manufacturing and 32 high‐technology manufacturing). The results indicate a statistical association between the level of and changes in a limited number of assessed client risks (e.g., management aggressiveness and the inherent risk of an existence misstatement) and evidential plans. In addition, audit programs were found to change little over time with many tests done across a broad array of engagements. Overall, the responsiveness of evidential plans to risks,...
Designer magnets containing cyanides and nitriles.

Magnets synthesized from molecules have contributed to the renaissance in the study of magnetic materials. Three-dimensional network solids exhibiting magnetic ordering have been made from several first-row metal ions and bridging unsaturated cyanide, tricyanomethanide, and/or dicyanamide ligands. These materials possess several different structural motifs, and the shorter the bridge, the stronger the interaction (i.e., C⋮N > N⋮CN ≫ N⋮CNC⋮N = N⋮CCC⋮N). Cyanide additionally has the ability to discriminate between C- and N-bonding to form ordered heterobimetallic magnets, and the strong coupling can lead to ferro- or ferrimagnetic ordering substantially above room temperature. Tricoordination of tricyanomethanide results in spin-frustrated systems, which possess interpenetrating rutile-like networks. In contrast, single rutile-like frameworks are formed by μ3-bonded dicyanamide, which leads to ferromagnetics and weak ferromagnetics.
The flow pattern and residence time distribution for an endless belt solid–liquid contactor

The flow pattern and residence time distribution (RTD) for an endless belt mass transfer device have been studied theoretically and experimentally. Even within the laminar regime the overall flow pattern shows several interesting features, with a wide range of different RTDs, depending on the relative velocities of fluid and belt. At high relative belt speeds the RTDs for cocurrent and countercurrent flow approach the same limiting form and at long residence times the system behaves as a single well mixed vessel. The restrictions imposed by the flow behavior on the practical range of operation as a mass transfer device are briefly considered.
Quantized field formulation of the free electron laser in the heisenberg picture

Abstract The phase and amplitude operator equations valid for field intensities ranging from a single photon state to an intense laser state are derived by means of quantized field theory. Using the Dirac equation, driving current operators, which are expressed by radiation and electron fields, are separated into spontaneous, stimulated, and spin terms. Then, utilizing the semiclassical nature of the electron state, coherence condition and spectral equations are derived. From the spectral phase equation, a delay-time scaling for oscillator operation is obtained in good agreement with experiments.
The DEEP Groth Strip Survey. IX. Evolution of the Fundamental Plane of Field Galaxies

Fundamental plane studies provide an excellent means of understanding the evolutionary history of early-type galaxies. Using the Low Resolution Imaging Spectrograph on the Keck Telescope, we obtained internal stellar kinematic information for 36 field galaxies in the Groth Strip, 21 early-type and 15 disk galaxies. Their redshifts range from 0.3 to 1.0, with a median redshift of 0.8. The slope of the relation shows no difference compared with the local slope. However, there is significant evolution in the zero-point offset; an offset due to evolution in magnitude requires a 2.4 mag luminosity brightening at z = 1. We see little differences of the offset with bulge fraction, which is a good surrogate for galaxy type. Correcting for the luminosity evolution reduces the orthogonal scatter in the fundamental plane to 8%, consistent with the local scatter. This scatter is measured for our sample and does not include results from other studies, which may have different selection effects. The difference in the degree of evolution between our field sample and published cluster galaxies suggests a more recent formation epoch, around z = 1.5 for field galaxies compared to z > 2.0 for cluster galaxies. The magnitude difference implies that the field early-type galaxies are about 2 Gyr younger than the cluster ellipticals using standard single-burst models. However, the same models imply a significant change in the rest-frame U-B color from then to the present, which is not seen in our sample. Continuous low-level star formation, however, would serve to explain the constant colors over this large magnitude change. A consistent model has 7% of the stellar mass created after the initial burst, using an exponentially decaying star formation rate with an e-folding time of 5 Gyr.
Spinors and Pre-Metric Electromagnetism

The basic concepts of the formulation of Maxwellian electromagnetism in the absence of a Minkowski scalar product on spacetime are summarized, with particular emphasis on the way that the electromagnetic constitutive law on the space of bivectors over spacetime supplants the role of the Minkowski scalar product on spacetime itself. The complex geometry of the space of bivectors is also summarized, with the intent of showing how an isomorphic copy of the Lorentz group appears in that context. The use of complex 3-spinors to represent electromagnetic fields is then discussed, as well as the expansion of scope that the more general complex projective geometry of the space of bivectors suggests.
Submarine Location Estimation Via a Network of Detection-Only Sensors

It is well known to active-sonar engineers that the reflected signal from a target can be highly aspect dependent; hence, in many cases, only receivers located in a particular zone determined by the source/target receive geometry, and the target aspect can detect the return signal. Thus, submarines can hide well from traditional sonar systems. For these low-visibility targets, we propose a target localization paradigm based on a distributed sensor network which consists of low complexity sensors that only report binary detection results. Based on binary outputs and the positions of the sensors, we develop optimal maximum likelihood and suboptimal line-fitting-based estimators and derive the Crameacuter-Rao lower bound on estimation accuracy. We extend our results from single source to multisource settings, both with and without explicit incorporation of a reflection model that links the target orientation to the propagation direction. Our numerical results verify the feasibility of the proposed estimators. We do not rely on continuous quantities such as signal strength, direction of arrival, time or time-difference of arrival, and, instead, localize based on discrete detection results, which include both false alarms and missed detections
Deregulation Despite Transitional Gains – The Brewers Guild of Cologne 1461

Acemoglu and Robinson (in The American Economic Review 90(2):126–130, 2000) argue that historically economic rents have been less of a barrier to regulatory reform and innovation than political rents. Contrary to this conclusion, I argue that the important margin of distinction for factors preventing deregulation is not whether rents are economic or political, but rather what alternative profit opportunities are available and how innovation has changed the entrepreneurial opportunity set. Using the example of medieval Cologne, I show that the transitional gains trap framework, as developed by Tullock (in The Bell Journal of Economics 6(2):671–678, 1975), applies in a static environment and can successfully prevent reform over long periods of time, but that neither political nor economic entrepreneurs will ignore an opportunity for increased profitability in the long run. In addition, the organization of the political unit to which the regulation applies can determine the persistence of said regulation.
Petascale Computing for Large-Scale Graph Problems

Summary form only given. Graph theoretic problems are representative of fundamental kernels in traditional and emerging computational sciences such as chemistry, biology, and medicine, as well as applications in national security. Yet they pose serious challenges for parallel machines due to non-contiguous, concurrent accesses to global data structures with low degrees of locality. Few parallel graph algorithms outperform their best sequential implementation due to long memory latencies and high synchronization costs. In this talk, we consider several graph theoretic kernels for connectivity and centrality and discuss how the features of petascale architectures will affect algorithm development, ease of programming, performance, and scalability.
Effects of sugar and fat on the sensory properties of milk chocolate: descriptive analysis and instrumental measurements†

The sensory properties of nine milk chocolate formulations varying in sucrose (400, 475 or 550 g kg−1) and cocoa butter (280, 320 or 360 g kg−1) were evaluated by descriptive analysis with a panel of 18 trained judges and by instrumental measures of colour lightness, hardness, viscosity and yield value. Low-sugar samples were more bitter, gritty and roasted (p < 0.001). High-sugar samples had higher milky/dairy, vanilla/caramel, hardness and sweetness intensities (p < 0.001). Samples higher in fat were faster melting. Low-sugar and low-fat samples were associated with viscous, mouthcoating, fatty/oily, cocoa and darker notes. Samples with high levels of both sugar and fat were more cooling and faster vanishing (p < 0.001). Surprisingly, fatty/oily intensity was inversely related to fat concentration. This research documents previously unreported effects of sugar and fat on the texture, mouthfeel and flavour of milk chocolate. © 1999 Society of Chemical Industry
Achieving Congestion Diversity in Multi-Hop Wireless Mesh Networks

This paper reports on a comprehensive study comparing congestion-aware routing algorithms for wireless mesh networks with a state-of-the-art shortest-path routing protocol: Link-Quality Source Routing (LQSR). In particular, a set of congestion-aware protocols in the literature, Backpressure (BP), Enhanced-Backpressure (E-BP) and Congestion Diversity Protocol (CDP) are suitably adapted for implementation on 802.11-compatible radios. A testbed consisting of 802.11g nodes is deployed to empirically compare the performance of these congestion-aware routing protocols against LQSR. The results show that, under moderate to heavy UDP traffic, CDP delivers significant improvement compared to LQSR in 80-90 percent of the instances studied, while backpressure-based routing algorithms (BP and E-BP) frequently show significant degradation with respect to LQSR for both UDP and TCP traffic.
The political economy of technology adoption: The case of Saharan salt mining

Abstract Innovation is an important driver of economic growth and competitive advantage. A diverse literature in economics and management addresses a variety of questions about how to manage associated technological change. This paper explores the “opposite” question: Namely, what explains the absence of change? We apply existing theories of non-adoption to our case study, salt mining in the Sahara Desert, in order to generate new insights into barriers to technology adoption. We find that political organization establishes an environment for the formation of higher-order economic organizations, which in turn affect the direction and rate of technology adoption. Our setting seems exotic, but traditional methods of production persist in myriad impoverished settings, including those containing widespread artisanal and small-scale mining (ASM) activity. The study thus sheds light on the role of institutions in economic growth.
Renegotiation and Optimality in Agency Contracts

We analyse renegotiation in a hidden action principal-agent model. Contract renegotiation offers are made by the agent. A refinement is imposed on the principal's beliefs: if precisely one action is optimal with respect to both the principal's and the agent's contracts, the principal believes that that action has been taken. With the refinement imposed, perfect-Bayesian equilibrium allocations are identical to the second best in the classical principal-agent model without renegotiation. When renegotiation is led by the agent and when equilibria satisfy the refinement, equilibrium allocations are ex ante efficient. Incentive contracting is a common mechanism for promoting ex ante investments and for avoiding ex post opportunistic behaviour in a long-term or continuing economic relationship. The classical principal-agent model (Holmstrom (1979), Grossman and Hart (1983)) is a natural framework for this class of problem. In such a model, a risk-averse agent performs an action on behalf of a risk-neutral principal; the agent's action is unobservable and affects the principal's revenue in a random fashion. The derivation and characterization of efficient compensation schemes have been the major focus in the principal-agent literature. Generally, the incentives to motivate a costly action from the agent take the form of "profit sharing:" the agent's reward is made contingent on his random performance outcomes.
The development and in vivo function of T helper 9 cells

This Review summarizes our current understanding of the key factors that regulate the differentiation of T helper 9 (TH9) cells. The authors discuss how TH9 cells can contribute to protective immunity to infection but may also drive immunopathology in diseases such as allergic asthma and inflammatory bowel disease.
Alcohol-related electrophysiology

Considerable effort has been expended to determine the electrophysiological actions of ethanol (EtOH) on nervous tissue. However, the site and mechanisms of EtOH intoxication, tolerance and dependence remain largely unknown. We and our co-workers have used two central mammalian models to clarify these problems: the rat cerebellar Purkinje cell (CPC) and the rat hippocampal pyramidal cell (HPC). Direct application of EtOH to CPCs via micro-electroosmosis or micropressure depresses spontaneous discharge weakly, while tetrahydropapaveroline (THP) depresses firing markedly. Single IP injections of EtOH (1–4 g/kg) increase the frequency of climbing-fiber (CF)-evoked bursts in CPCs but only occasionally increase simple-spike rates. However, CPCs of rats chronically treated with EtOH for 11–14 days and recorded 0–3 hrs after the last EtOH dose do not differ from controls. Rats chronically treated and then withdrawn from EtOH show significant decreases in CF activity and simple-spike rates 3–32 hrs after the last EtOH dose. These changes in CPC firing may be neuronal correlates of EtOH intoxication, tolerance and dependence. In the hippocampus, with direct application of EtOH to HPCs in vivo about half of the cells are excited and half inhibited. Salsolinol excites most HPCs, in parallel with opiate actions. THP is mostly inhibitory. EtOH and salsolinol excitatory effects are often antagonized by naloxone. With intracellular recording in the hippocampal slice, EtOH perfusion (10–400 mM) has mixed de-polarizing/hyperpolarizing actions, depending on dose and time of application. Excitations may arise from depolarization, increase in membrane resistance, enhancement of evoked EPSPs or block of IPSPs, in contrast to opiate actions which are always associated with reduction in IPSPs. In vivo, systemic EtOH (3 g/kg, IP) significantly enhances both excitatory and inhibitory responses to stimulation of afferent pathways to HPCs. The excitatory EtOH actions on HPCs may relate to the hippocampal EEG spiking sometimes elicited by low doses of EtOH. However, further studies are needed to verify a link with opiate-like mechanisms.
On the Y555 complex reflection group

Abstract We give a computer-free proof of a theorem of Basak, describing the group generated by 16 complex reflections of order 3, satisfying the braid and commutation relations of the Y 555 diagram. The group is the full isometry group of a certain lattice of signature ( 13 , 1 ) over the Eisenstein integers Z [ 1 3 ] . Along the way we enumerate the cusps of this lattice and classify the root and Niemeier lattices over Z [ 1 3 ] .
One-way permutations and self-witnessing languages

A desirable property of one-way functions is that they be total, one-to-one, and onto--in other words, that they be permutations. We prove that one-way permutations exist exactly if P ≠ UP ∩ coUP. This provides the first characterization of the existence of one-way permutations based on a complexity-class separation and shows that their existence is equivalent to a number of previously studied complexity-theoretic hypotheses. We study permutations in the context of witness functions of nondeterministic Turing machines. A language is in PermUP if, relative to some unambiguous, nondeterministic, polynomial-time Turing machine accepting the language, the function mapping each string to its unique witness is a permutation of the members of the language. We show that, under standard complexity-theoretic assumptions, PermUP is a strict subset of UP. We study SelfNP, the set of all languages such that, relative to some nondeterministic, polynomial-time Turing machine that accepts the language, the set of all witnesses of strings in the language is identical to the language itself. We show that SAT ∈ SelfNP, and, under standard complexity-theoretic assumptions, SelfNP ≠ NP.
The Focusing of Charged Particles by a Spherical Condenser

The paths of charged particles traversing a portion of an ideal spherical condenser are worked out. The section of the condenser considered is bounded by two rays, enclosing an angle $\ensuremath{\Phi}$, from the common center of curvature, $O$, of the equipotential surfaces. It is shown that a group of particles, homogeneous in energy, leaving a point $P$ on a normal to one of these boundaries and entering the condenser along this normal as a diverging bundle, will be brought to a focus at a point $Q$ lying on the line $\mathrm{PO}$ extended, if the proper potential is applied to the condenser. This permits the whole condenser gap to be used as a focusing energy analyzer, or monochromator, of very large useful aperture. The velocity dispersion and reduced velocity dispersion are calculated for the most general case, and are found to take the same simple form as do the corresponding expressions for the limited homogeneous magnetic field spectrograph. The expressions for the reduced velocity dispersion are identical in the two cases. Compensation for edge effect is discussed. The relativistic modification of the theory required for high speed particles is discussed and results are presented which indicate that the simple theory of the electrostatic spectrograph may be inadequate even for fairly low values of $\frac{v}{c}$. It is suggested that this difficulty may be avoided by the choice of suitable instrument parameters.An analyzer is described which has a useful aperture of 0.210 steradians, a theoretical reduced dispersion of 1010, and which requires a total focusing potential of 0.315 $E$, where $E$ is the particle energy in equivalent volts. The operation of the analyzer in focusing electrons accelerated by a field designed to furnish an equivalent point source is described.
Vortex loop fluctuations in Casimir thinning of helium films

A vortex-loop renormalization theory is used to calculate the Casimir forces that lead to the thinning of 4 He films near the superfluid transition point. For periodic boundary conditions it is found that the force is appreciable when the loop size becomes comparable to the film thickness. The results for T T c .
Effects of surface forces and film elasticity on foam stability

The thin film pressure balance (TFPB) technique was used to determine the surface forces in foam films stabilized with flotation frothers such as n-pentanol, n-octanol, methyl isobutyl carbinol (MIBC), and polypropylene glycol (PPG). The results were compared with the foam stabilities measured experimentally and the film elasticities calculated using a model developed by Wang and Yoon [Wang, L., Yoon, R.-H., 2006a. Role of hydrophobic force in the thinning of foam films containing a nonionic surfactant. Colloids Surfaces A: Physicochem. Eng. Aspects, 282–283, 84–91.]. It was found that foam stabilities are controlled by both film elasticity and disjoining pressure, the relative contributions from each changing with frother type and concentration. At relatively low concentrations, frother dampens the hydrophobic force, an attractive component of the disjoining pressure, that destabilizes foams. At higher concentrations, elasticity plays a more important role in stabilizing foams. Copyright © 2007 Elsevier B.V. All rights reserved.
Bayesian Belief Networks for predicting drinking water distribution system pipe breaks

Abstract In this paper, we use Bayesian Belief Networks (BBNs) to construct a knowledge model for pipe breaks in a water zone. To the authors’ knowledge, this is the first attempt to model drinking water distribution system pipe breaks using BBNs. Development of expert systems such as BBNs for analyzing drinking water distribution system data is not only important for pipe break prediction, but is also a first step in preventing water loss and water quality deterioration through the application of machine learning techniques to facilitate data-based distribution system monitoring and asset management. Due to the difficulties in collecting, preparing, and managing drinking water distribution system data, most pipe break models can be classified as “statistical–physical” or “hypothesis-generating.” We develop the BBN with the hope of contributing to the “hypothesis-generating” class of models, while demonstrating the possibility that BBNs might also be used as “statistical–physical” models. Our model is learned from pipe breaks and covariate data from a mid-Atlantic United States (U.S.) drinking water distribution system network. BBN models are learned using a constraint-based method, a score-based method, and a hybrid method. Model evaluation is based on log-likelihood scoring. Sensitivity analysis using mutual information criterion is also reported. While our results indicate general agreement with prior results reported in pipe break modeling studies, they also suggest that it may be difficult to select among model alternatives. This model uncertainty may mean that more research is needed for understanding whether additional pipe break risk factors beyond age, break history, pipe material, and pipe diameter might be important for asset management planning.
A new approach to archaebacterial lipid models

Abstract 1,1'-(α,ω-Alkylidene)-2,2'-dialkylglycerol tetraether lipid models ( 9 ) have been prepared by coupling two equivalents of 1-(ω-haloalkyl-2-alkylglycerol diethers, through silver-catalyzed coupling of the Grignard reagents 8 with iodide 7 .