cssi/SciSciGPT-SciSciNet huggingface dataset:
Toward a multilateral framework for identifying national security threats posed by foreign acquisitions: with special reference to Chinese acquisitions in the United States, Canada, and Australia

This article presents a framework for differentiating between foreign acquisitions of companies that might plausibly pose a national security threat to the home country of the target acquisition and those that do not. This framework originally derives from the experience of the United States. The framework is then shown to be relevant and useful for foreign acquisitions in Canada and Australia. In each case, Chinese acquisitions of US, Canadian, or Australian firms are highlighted. The article concludes by arguing that this framework can serve as an effective nondiscriminatory basis for separating genuine from implausible national security threats from foreign acquisitions across OECD states, to include all countries around the world.
HYCAT: HYBRID HYDROFOIL CATAMARAN CONCEPT

Abstract A hybrid marine vehicle concept has been developed which utilizes a combination of static and dynamic support. This concept, termed HYCAT † for HYdrofoil CATamaran, combines a planing catamaran hull with two fully submerged hydrofoils mounted in tandem fore and aft. The hullform is developed by adding a high length/beam ratio, high deadrise sidehull along the keel of each catamaran demihull. The sidehull, which is the only portion immersed when operating foilborne, provides buoyancy support. Spray strips provide discontinuities which separate the flow and provide dynamic lift in addition to the hydrofoils. Stability in the heave, pitch and roll degrees of freedom is achieved through the displacement dependent sidehull buoyancy and the rate and displacement dependent lift developed by the spray strips and hydrofoils. A comprehensive series of model tests has been conducted to characterize the smooth and rough water performance.
The Wolff-Parkinson-White syndrome: problems in evaluation and surgical therapy.

Two patients with WPW syndrome underwent surgery to ablate accessory conduction pathways. Endocardial and epicardial mapping in both patients had indicated an area of early right ventricular depolarization. Surgical transection of the areas of early depolarization failed in both cases to normalize the electrocardiogram. In the first patient, additional resection in the area of the A-V node failed to produce heart block and the ECG remained abnormal. However, the paroxysmal tachycardia ceased, and she has remained asymptomatic and active 12 months after surgery. In the second patient, as the A-V node was about to be sectioned, pressure and procaine near the A-V node caused the ECG to normalize transiently and after resection permanently. Microscopic study of this tissue showed "P cells." Postoperatively the patient demonstrated normal A-V nodal function. He was discharged with a normal ECG but expired soon after discharge. Postmortem examination of the heart demonstrated the A-V node and bundle of His plus the location of the resection adjacent to the bundle of His. These two cases illustrate disparities between electrophysiologic mapping and actual site of the accessory conduction pathway. In one of the cases an accessory bundle was demonstrated histologically.
STORAGE RINGS FOR NUCLEAR PHYSICS

Abstract Although still a relatively new development, exploitation of the technology of storage rings has been playing an increasing role in the field of nuclear science. These few remarks present a subjective view of some of the progress and problems in this ring application.
New N = 1 superconformal field theories in four dimensions from D-brane probes

We present several new examples of non-trivial 4D N = 1 superconformal field theories. Some of these theories exhibit exotic global symmetries, including non-simply laced groups (such as F4). They are obtained by studying three-brane probes in F-theory compactifications on elliptic Calabi-Yau threefolds. The geometry of the compactification encodes in a simple way the behavior of the gauge coupling and the Kahler potential on the Coulomb branch of these theories.
External Communication and Project Performance: An Investigation Into the Role of Gatekeepers

Research indicates that certain boundary spanning individuals, labelled gatekeepers, can be an important linking mechanism between organizations and their external environments. This study investigates the role of gatekeepers in the transfer of information in a single RD they appear to facilitate the external communication of their more local project colleagues. Direct contact and contact mediated by gatekeepers, then, are two contrasting ways to link project groups with their external areas. The relative effectiveness of these linking mechanisms is contingent on the nature of the project's work.
Functional verification of power gated designs by compositional reasoning

Power gating is a technique for low power design in which whole sections of the chip are powered off when they are not needed, and powered back on when they are. Functional correctness of power gating is usually checked at the system level, where the most widely used technique is simulation using pseudo-random stimuli. This normally entails running extremely expensive ternary simulations, in order to model the memory loss that occurs as a result of a memory element being powered off. We propose instead a methodology in which we prove sequential equivalence between the power gated design and a simplified version of itself, then use the simplified version in a binary simulation. We use a compositional approach that looks for partial equivalence of each unit under a suitable set of assumptions, guaranteed by the neighboring units. The partial equivalences are then composed into total equivalence on the whole chip. Our method is applicable to any power gated design, no matter the side effects (e.g., in timing of events across the interfaces) caused by the particular implementation of power gating.
Synthesis of (+/-)-Gymnomitrol. Mn(OAc)(3)-Initiated Free-Radical Cyclization of Alkynyl Ketones.

Mn(OAc)3-initiated cyclization of alkynyl ketones in 9−19:1 EtOH/HOAc at 90 °C is a useful cyclization procedure in favorable cases. Cyclization of (trimethylsilyl)alkynyl ketone 4e provides 62% of silylalkenes 26 and 27 in the key reaction of a seven-step (16% overall yield) synthesis of gymnomitrol (1) from readily available ketone 23. 9α-Hydroxygymnomitryl acetate (2) and 9-oxogymnomitryl acetate (3) have been prepared from gymnomitrol. Cyclization of propargyl cyclohexanones 39a−c provides bicyclic compounds 40−42 in 40−60% yield.
Corrosion performance of welded CRA-lined pipes for flowlines

This paper presents the results of corrosion and mechanical testing of welded high-nickel, corrosion-resistant-alloy (CRA)- lined pipes manufactured using various lining processes. The corrosion resistance of CRA-lined pipes for use as a flowline material in sour service was evaluated. The effects of the manufacturing process, CRA lining material, and welding on the corrosion performance of CRA-lined pipes also were determined
Tiempo: cuerpo y memoria,salones y recorridos

La aceleracion de nuestra cultura ha hecho que lo que separa pasado, presente y futuro sea de una consistencia cada vez mas atenuada e ilegible. Y los arquitectos, antes inequivocamente inclinados a la permanencia y a la durabilidad, hoy incorporan la palabra temporal (luego de novedad, joven, reciente) como valor convencional. ?Como situarse en una epoca en que la avidez por lo nuevo se transforma, en palabras de Javier Marias, en "el desden por lo que existe y la fascinacion por lo inexistente"? La arquitectura, entre demoliciones, remodelaciones y persistencias, se resiste a un destino estatico: toda ella aparece como registro de lo que ya ha pasado, pero ciertamente es el reflejo de lo que esta siendo hoy.
Efficiency tests of agricultural commodity futures markets in China

The efficiency of the Chinese wheat and soybean futures markets is studied. Formal statistical tests were conducted based on Johansen's cointegration approach for three different cash markets and six different futures forecasting horizons ranging from 1 week to 4 months. The results suggest a long-term equilibrium relationship between the futures price and cash price for soybeans and weak short-term efficiency in the soybean futures market. The futures market for wheat is inefficient, which may be caused by over-speculation and government intervention.
Are there elimination algorithms for the permanent

We define the class of elimination algorithms. There are algebraic algorithms for evaluating multivariate polynomials, and include as a special case Gaussian elimination for evaluating the determinant. We show how to find the linear symmetries of a polynomial, defined appropriately, and use these methods to find the linear symmetries of the permanent and determinant. We show that in contrast to the Gaussian elimination algorithm for the determinant, there is no elimination algorithm for the permanent.
Effects of Counterions on Crack Growth in Vitreous Silica

Crack-growth studies on vitreous silica were conducted in aqueous solutions as a function of pH in- the range 1 to 14. Slopes of crack velocity-KI curves were steeper in acidic and neutral solutions than in basic solutions. Of the four alkali-metal hydroxide solutions studied, only lithium hydroxide behaved differently from the others and only in concentrated, ≥1M, solutions. At this concentration, the slope and position of the crack-growth curves for LiOH were nearly identical to those obtained in acidic or neutral solutions. It is suggested that the influence of alkali-metal hydroxides on crack growth is largely chemical in nature, involving short-range forces associated with the breaking of bonds at the crack tip. Two mechanisms for chemical attack are considered: in basic solutions the siloxane bonds at the crack tip are believed to be attacked directly by the hydroxide ions in solution; in acidic or neutral solutions the siloxane bonds are believed to be attacked by water in the electrolyte. Lithium hydroxide behaves differently from the others because lithium ions associate with hydroxide ions, reducing the effective activity of the hydroxide ions at the crack tip.
Thermodynamics and kinetics of folding of a small peptide

We study the thermodynamics and kinetics of folding for a small peptide. Our data rely on Monte Carlo simulations where the interactions among all atoms are taken into account. Monte Carlo kinetics is used to study folding of the peptide at suitable temperatures. The results of these canonical simulations are compared with that of a generalized-ensemble simulation. Our work demonstrates that concepts of folding which were developed in the past for minimalist models hold also for this peptide when simulated with an all-atom force field.
Preoperative adjuvant radiation with chemotherapy for rectal cancer: Its impact on stage of disease and the role of endorectal ultrasound

Background Preoperative adjuvant radiation combined with chemotherapy is a recent development in the management of patients with rectal cancer invading perirectal tissue and regional lymph nodes. This study was performed to assess the impact of preoperative adjuvant therapy in patients judged by endorectal ultrasound to have extramural invasion of rectal cancer and/or regional lymph node involvement on tumor regression in bowel wall and lymph nodes. The predictive value of ultrasound in staging wall penetration and lymph node involvement after preoperative adjuvant therapy was also assessed. Methods Patients (n = 43) were selected by ultrasound to have preoperative irradiation (4,500-5,040 cGy over 5-6 weeks). In 30 patients this was combined with 5-fluorouracil, 370 mg/m(2), for 5 days in the first and last weeks of irradiation. Pretreatment ultrasound was compared with pathologic findings in the resected specimen in all patients. Twenty-one were assessed by ultrasound after adjuvant therapy and findings compared with histology. Results Downstaging was seen in 23 (53%) patients with wall invasion and in 23 (72%) of 32 patients with lymph node involvement. Overall, downstaging was achieved in 30 (70%). Positive predictive values of ultrasound after irradiation were 72% and 56% for wall penetration and lymph node status, respectively. Negative predictive values of ultrasound after irradiation were 100% and 82%, respectively. Conclusion In the majority of patients with rectal cancer invading perirectal tissues or lymph nodes, lesions may be downstaged by preoperative adjuvant therapy. Endorectal ultrasound after adjuvant therapy for rectal cancer is of a lesser predictive value chiefly because of overstaging.
A distributed line search for network optimization

Dual descent methods are used to solve network optimization problems because descent directions can be computed in a distributed manner using information available either locally or at neighboring nodes. However, choosing a stepsize in the descent direction remains a challenge because its computation requires global information. This work presents an algorithm based on a local version of the Armijo rule that allows for the computation of a stepsize using only local and neighborhood information. We show that when our distributed line search algorithm is applied with a descent direction computed according to the Accelerated Dual Descent method [18], key properties of standard backtracking line search using the Armijo rule are recovered. We use simulations to demonstrate that our algorithm is a practical substitute for its centralized counterpart.
The correlation dimension of differenced data

Abstract The effect differencing has on the estimated correlation dimension of a non-Gaussian time series is discussed. Two different methods for generating surrogate data sets are compared. The results suggest that any filtering should be applied to both the raw and surrogate time series, otherwise spurious results can occur.
Dynamical Models of Elliptical Galaxies in z = 0.5 Clusters. II. Mass-to-Light Ratio Evolution without Fundamental Plane Assumptions

We study the mass-to-light ratio (M/L) evolution of early-type galaxies using dynamical modeling of resolved internal kinematics. This makes fewer assumptions than fundamental plane (FP) studies and provides a powerful new approach for studying galaxy evolution. We focus on the sample of 25 galaxies in clusters at z ? 0.5 modeled in Paper I. For comparison, we compile and homogenize M/L literature data for 60 nearby galaxies that were modeled in comparable detail. The nearby sample obeys log(M/L)B = Z + S log(?eff/200 km s-1), where Z = 0.896 ? 0.010, S = 0.992 ? 0.054, and ?eff is the effective velocity dispersion. The z ? 0.5 sample follows a similar relation, but with lower zero point. The implied M/L evolution is ? log(M/L)/?z = -0.457 ? 0.046(random) ? 0.078(systematic), consistent with passive evolution following high-redshift formation. This agrees with the FP results for this sample by van Dokkum & van der Marel, and confirms that FP evolution tracks M/L evolution, which is an important verification of the assumptions that underlie FP studies. However, while we find more FP evolution for galaxies of low ?eff (or low mass), the dynamical M/L evolution shows little correlation with ?eff. We argue that this difference can be plausibly attributed to a combination of two effects: (1) evolution in structural galaxy properties other than M/L, and (2) the neglect of rotational support in studies of FP evolution. The results leave the question open as to whether the low-mass galaxies in the sample have younger populations than the high-mass galaxies. This highlights the general importance in the study of population ages for complementing dynamical measurements with broadband colors or spectroscopic population diagnostics.
RTL verification of timed asynchronous and heterogeneous systems using symbolic model checking

Abstract This paper describes a tool-supported methodology for the register-transfer-level formal verification of a growing hardware design paradigm-timed asynchronous systems. These systems are a network of communicating asynchronous and synchronous components and have correctness constraints that depend on specified bounded delays. This paper formalizes the verification problem and demonstrates how time discretization, abstraction, and non-determinism can be used to obtain a system model comprised of communicating finite state machines that are composed synchronously. The paper then describes a translator that accepts structural VHDL system description along with controller specifications and generates the input to a symbolic model checker (SMV). Finally, we describe two case studies in which concurrent verification and design led to the correction of many errors not easily found using simulation.
Rhodium-catalyzed cycloisomerization of N-propargyl enamine derivatives.

A novel rhodium-catalyzed cycloisomerization has been developed which converts N-propargyl enamine derivatives to their isomeric six-membered azacycles in good yields under mild reaction conditions. The [Rh(C2H2)2Cl]2/P(4-F−C6H4)3 catalyst, in combination with DABCO as a base and DMF as a solvent, was found to be effective in promoting the cyclization process. The reaction is proposed to proceed through an intramolecular nucleophilic attack of the enamine to the rhodium vinylidene followed by a base-mediated proton-shunting process. The base was found to play a crucial role in the transformation, indicating the proton migration to be an integral component of the catalytic cycle. An aprotic polar solvent was required for high conversion, which points to the intermediacy of a zwitterionic intermediate. The present reaction should prove useful for the efficient synthesis of various six-membered azacycles that are important structural motifs of many natural isolates and medicinal agents.
On the optimal evaluation of a set of bilinear forms

Abstract Although general theories are beginning to emerge in the area of automata based complexity theory, there are very few general methods or even general problem formulations in the area of arithmetic complexity. In this paper we propose and defined a general model for studying bilinear multiplication in order to provide a common framework for discussing a wide class of problems. The problem of minimizing the number of multiplications required to perform a calculation leads to a problem in matrix algebra relating to the expansion of a given set of matrices as linear combinations of rank-one matrices. In this paper we make a systematic attack on this problem and derived some general results which unify and extend numerous known results.
Comptonization and QPO origins in accreting neutron star systems

We develop a simple, time-dependent Comptonization model to probe the origins of spectral variability in accreting neutron star systems. In the model, soft ‘seed photons’ are injected into a corona of hot electrons, where they are Compton upscattered before escaping as hard X-rays. The model describes how the hard X-ray spectrum varies when the properties of either the soft photon source or the Comptonizing medium undergo small oscillations. Observations of the resulting spectral modulations can determine whether the variability is due to (i) oscillations in the injection of seed photons, (ii) oscillations in the coronal electron density, or (iii) oscillations in the coronal energy dissipation rate. Identifying the origin of spectral variability should help clarify how the corona operates and its relation to the accretion disc. It will also help in finding the mechanisms underlying the various quasi-periodic oscillations (QPOs) observed in the X-ray outputs of many accreting neutron star and black hole systems. As a sample application of our model, we analyse a kilohertz QPO observed in the atoll source 4U 1608–52. We find that the QPO is driven predominantly by an oscillation in the electron density of the Comptonizing gas.
Stereocontrol in diels—alder cycloaddition to unsaturated sugars: reactivities of cis-dienophiles with cyclopentadiene☆

Abstract Cycloaddition of cyclopentadiene with a d -arabinose-derived cis -dienophile, methyl ( Z )-4,5,6,7-tetra- O -acetyl-2,32-dideoxy- d - arabino -hept-2-enonate ( 2 ), under thermal conditions gave essentially a single norbornene aduct, isolated crystaline in 81% yield and identified by NMR spectroscopy and X-ray crystallography as methyl ( 5R ,6S)-6- endo -(1,2,3,4-tetra- O -acetyl- d - arabino -tetritol-1-yl) bicyclo[2.2.1]-hept-2-ene-5- endo -carboxylate ( 3 ). The diene adds exclusively from the si -face of the dienophile and give only the endo product. The same sequence starting from l -arabinose gave the enantiomer ( 7 ) of 3 . In contrast, a related cis -dienophile ( 9 ) having a butenolide ring with cyclopentadiene from the opposite ( re ) face giving mainly the endo adduct (5S,6R)-6- endo -(2,3,4-tri- O -acetyl)- d - arabino -tetritol-1-yl) bicyclo[2.2.1]hept-2-ene-5- endo -carboxylic acid 1,4-lactone ( 10 ), isolated crystalline in 70% yield, whose structure was again established by NMR spectroscopy, and firmly consolidated by X-ray crystallography. The minor (11%) product was the exo (5S,6R)isomer 11 . A cis -enonate 14 , analogous to 2 but deoxygenated at the allylic position, showed negligible diastereofacial selectivity ans reacted with cyclopentadiene to give a mixture of all four possible adducts. A 6-membered ring dienophile 16 was also subjected to the same cycloaddition for comparison with the butenolide 9 ; it gave principally the two endo products 17 and 19 in 31 and 38% yields, respectively, accompanied by 12% of a mixture of the two exo products ( 18 and 20 ). The quantitative distribution of cycloaddition products as a function of dienophile stereochemistry is discussed. The high degree of asymmetric induction observed, especially with the readily accesible dienophiles 2 and 7 , providesa valuable route of access to enantiomerically pure tetra- C -substituted cycloalkanes.
A comparison of the effects of three types of endurance training on balance and other fall risk factors in older adults.

We hypothesized that short-term endurance training improves balance in older adults, if training involves movements that “stress” balance. We tested the hypothesis by looking for a dose-response relationship between movement during exercise and balance improvement. The study was a single-blinded, randomized controlled trial. Subjects were sedentary adults (N=106) aged 68–85 with at least mild deficits in balance. Exercise groups were: stationary cycle (low movement), walking (medium movement), and aerobic movement (high movement). Subjects attended supervised exercise classes three times a week for three months, followed by self-directed exercise of any type for three months. The primary test of the hypothesis compared changes in balance after three months of supervised exercise. One balance measure (distance walked on a six-meter narrow balance beam) improved in the hypothesized dose-response manner (cycle, 3% improvement; walking, 7% improvement; aerobic movement, 18% improvement: p 0.1). Leg strength improved significantly in all exercise groups. The study hypothesis was supported only for one balance measure. Only walking improved at least one measure of all major outcomes (endurance, strength, gait, balance, health status), suggesting that walking is most useful for fall prevention. Cycle exercise appeared least useful.
Low‐Temperature Sintering of Seeded Sol—Gel‐Derived, ZrO2‐Toughened Al2O3 Composites

Seeding a mixture of boehmite (AIOOH) and colloidal ZrO2 with α-alumina particles and sintering at 1400°C for 100 min results in 98% density. The low sintering temperature, relative to conventional powder processing, is a result of the small alumina particle size (∼0.3 μm) obtained during the θ-to α-alumina transformation, homogeneous mixing, and the uniform structure of the sol-gel system. Complete retention of pure ZrO2 in the tetragonal phase was obtained to 14 vol% ZTA because of the low-temperature sintering. The critical grain size for tetragonal ZrO2 was determined to be ∼0.4 μm for the 14 vol% ZrO2—Al2O3 composite. From these results it is proposed that seeded boehmite gels offer significant advantages for process control and alumina matrix composite fabrication.
Extraction chez l'enfant

Resume Extraction chez l'enfant : cet acte peut paraitre a priori simple, voire banal. De son bon deroulement, au meme titre que les soins pedodontiques, va dependre le comportement du futur patient devenu adulte. Ainsi, le premier contact et l'abord de l'enfant sont essentiels ; le choix des termes dans la relation praticien - patient revet une grande importance. La denture lacteale presente des caracteristiques morphologiques et physiologiques qui la differencient de la denture permanente ; en premier lieu, la rhizalyse qui lui confere son caractere ephemere. La carie et ses complications infectieuses surtout, mais aussi les traumatismes constituent les causes principales d'extraction chez l'enfant. A celles-ci viennent s'ajouter les extractions pilotees, pour des raisons orthodontiques, qu'elles soient de dents temporaires ou de germes de dents permanentes. De l'indication a la realisation de l'acte, l'anesthesie constitue une etape intermediaire qui peut parfois devenir un obstacle (peur de la piqure). C'est pourquoi tout doit etre fait pour qu'elle soit la moins traumatisante possible. La technique operatoire doit obeir a des regles precises et tenir compte de facteurs tels que la morphologie des dents, la presence des germes des dents definitives sous-jacents et, durant un temps, la coexistence des deux dentures. Pour les actes plus complexes tels que l'extraction des odontoides ou plus generalement des dents incluses, le choix de l'anesthesie generale se discute.
The preparation and characterization of molecular dipotassiumhexaisobutyldihydridodialuminum

Abstract Treatment of i Bu 2 AlH with K affords K 2 Al 2 i - Bu 6 H 2 . The reactions of the latter with H 3 O + , DCl and Me 3 SiCl have been studied. Spectroscopic characterization involved NMR data; 1 H, 13 C, 27 Al and 39 K, as well as a discussion of an observed low energy v (AlH) (non-typical) in the infrared spectrum. Finally, possible geometries for K 2 Al 2 i Bu 6 H 2 are presented.
Cosmological Neutrino Background Revisited

We solve the Boltzmann equation for cosmological neutrinos around the epoch of the electron-positron annihilation in order to verify the freeze-out approximation and to compute accurately the cosmological neutrino distribution function. We find the radiation energy density to be about 0.3% higher than predicted by the freeze-out approximation. As a result, the spectrum of the cosmic microwave background anisotropies changes by ~0.3%-0.5%, depending on the angular scale, and the amplitude of the mass fluctuations on scales below about 100 h-1 Mpc decreases by about 0.2%-0.3%.
Stock Price Volatility in a Multiple Security Overlapping Generations Model

A number of empirical studies have reached the conclusion that stock price volatility cannot be fully explained within the standard dividend discount model. This article proposes a resolution based upon a model that contains both a random supply of risky assets and finitely lived agents who trade in a multiple security environment. As the analysis shows there exist 2 K equilibria when K securities trade. The low volatility equilibria have properties analogous to those found in the infinitely lived agent models of Campbell and Kyle (1991) and Wang (1993, 1994). In contrast, the high-volatility equilibria have very different characteristics. Within the high-volatility equilibria very large price variances can be generated with very small supply shocks. Adding securities to the economy further reduces the required supply shocks. Using previously established empirical results the model can reconcile the data with supply shocks that are less than 10% as large as observed return shocks. These results are shown to hold even when the dividend process is mean reverting.
Lattice Boltzmann simulations of decaying homogeneous isotropic turbulence

Decaying homogeneous isotropic turbulence in inertial and rotating reference frames is investigated to evaluate the capability of the lattice Boltzmann method in turbulence. In the inertial frame case, the decay exponents of kinetic energy and dissipation and the low wave-number scaling of the spectrum are studied. The results are in agreement with classical ones. In the frame-rotation case, simulations show that the energy decay rate decreases with decreasing Rossby number as the energy cascade is inhibited by rotation, again in agreement with turbulence physics. These results clearly indicate that the lattice Boltzmann method captures important features of decaying turbulence.
Analytical solution of electron spin decoherence through hyperfine interaction in a quantum dot

We analytically solve the non-Markovian single-electron spin dynamics due to hyperfine interaction with surrounding nuclei in a quantum dot. We use the equation-of-motion method assisted with a large field expansion, and find that virtual nuclear spin flip-flops mediated by the electron contribute significantly to a complete decoherence of the transverse electron spin correlation function. Our results show that a 90% nuclear polarization can enhance the electron spin time ${T}_{2}$ by almost two orders of magnitude. In the long time limit, the electron spin correlation function has a nonexponential $1∕{t}^{2}$ decay in the presence of both polarized and unpolarized nuclei.
Critical properties of an Ising model with dilute long range interactions

Abstract Statistical mechanical models with local interactions in d > 1 dimension can be regarded as d = 1 dimensional models with regular long range interactions. In this paper we study the critical properties of Ising models having V sites, each having z randomly chosen neighbors. For z = 2 the model reduces to the d = 1 Ising model. For z = ∞ we get a mean field model. We find that for finite z > 2 the system has a second order phase transition characterized by a length scale L = ln V and mean field critical exponents that are independent of z .
Nanostructured crystals: unique hybrid semiconductors exhibiting nearly zero and tunable uniaxial thermal expansion behavior.

A unique family of II−VI based nanostructured inorganic−organic hybrid semiconductors exhibit nearly zero uniaxial thermal expansion in the temperature range of 95−295 K. Both their optoelectronic and thermal expansion properties are systematically tunable. The diamine molecules show a strong negative thermal expansion effect, and the extent of such an effect increases as the length of the organic molecules increases.
Transient accident analysis of a supercritical carbon dioxide Brayton cycle energy converter coupled to an autonomous lead-cooled fast reactor

Abstract The supercritical carbon dioxide (S-CO2) Brayton cycle is a promising advanced alternative to the Rankine steam cycle and recuperated gas Brayton cycle for the energy converters of specific reactor concepts belonging to the U.S. Department of Energy Generation IV Nuclear Energy Systems Initiative. A new plant dynamics analysis computer code has been developed for simulation of the S-CO2 Brayton cycle coupled to an autonomous, natural circulation lead-cooled fast reactor (LFR). The plant dynamics code was used to simulate the whole-plant response to accident conditions. The specific design features of the reactor concept influencing passive safety are discussed and accident scenarios are identified for analysis. Results of calculations of the whole-plant response to loss-of-heat sink, loss-of-load, and pipe break accidents are demonstrated. The passive safety performance of the reactor concept is confirmed by the results of the plant dynamics code calculations for the selected accident scenarios.
Three dimensional periodic U(1) gauge theory and strings

Abstract It will be argued that among the known systems in three dimensions that have string like excitations periodic U(1) pure gauge theories are the most likely candidates to lead to a string representation of their universal properties. Some recent work with F. David will also be reviewed.
A Simultaneous Optical and X-Ray Variability Study of the Orion Nebula Cluster. II. A Common Origin in Magnetic Activity

We present a statistical analysis of simultaneous optical and X-ray light curves, spanning 600 ks, for 814 pre-main-sequence (PMS) stars in the Orion Nebula Cluster. The aim of this study is to establish the relationship, if any, between the sites of optical and X-ray variability and thereby to elucidate the origins of X-ray production in PMS stars. In a previous paper, we showed that optical and X-ray variability in PMS stars are very rarely time-correlated. Here, using time-averaged variability indicators to examine the joint occurrences of optical and X-ray variability, we confirm that the two forms of variability are not directly causally related. However, a strong and highly statistically significant correlation is found between optical variability and X-ray luminosity. As this correlation is found to be independent of accretion activity, we argue that X-ray production in PMS stars must instead be intimately connected with the presence and strength of optically variable, magnetically active surface regions (i.e., spots) on these stars. Moreover, because X-ray variability and optical variability are rarely time-correlated, we conclude that the sites of X-ray production are not exclusively cospatial with these regions. We argue that solar-analog coronae, heated by topologically complex fields, can explain these findings.
Extreme X-Ray Behavior of the Low-Luminosity Active Nucleus in NGC 4395

We present the results of a 17 ks Chandra ACIS-S observation of the nearby dwarf spiral galaxy NGC 4395. Chandra affords the first high-quality, broadband X-ray detection of the active nucleus of this object that is uncontaminated by nearby sources in the field. We find the nuclear X-ray source to be unresolved and confirm the rapid, large-amplitude variability reported in previous studies. The light curve appears to show ~11 cycles of a quasi-periodic oscillation with a period of ~400 s. If associated with an orbital feature near the innermost stable orbit of the accretion disk, this period would constrain the black hole mass to be M < 9 × 105 M⊙. The X-ray spectrum indicates absorption by an ionized medium, and the spectral shape appears to vary over the course of our observation. Contrary to prior reports, however, the spectral variations are uncorrelated with changes in the hard X-ray flux. It is possible that the short-term spectral variability we observe results from column density fluctuations in the ionized absorber. A power-law fit to the spectrum above 1 keV yields a photon index of Γ ≈ 0.6, much flatter than that typically observed in the spectra of Seyfert 1 galaxies. We have ruled out photon pile-up as the cause of the flat spectrum. Even when complex spectral features are considered, the photon index is constrained to be Γ < 1.25 (90% confidence). Comparing our results with previous determinations of the photon index (Γ = 1.46 and 1.72), we conclude that the slope of the primary continuum varies significantly on timescales of 1 yr or less. The extreme flatness and dramatic long-term variability of the X-ray spectrum are unprecedented among active galactic nuclei.
Sensing-aware kernel SVM

We propose a novel approach for designing kernels for support vector machines (SVMs) when the class label is linked to the observation through a latent state and the likelihood function of the observation given the state (the sensing model) is available. We show that the Bayes-optimum decision boundary is a hyperplane under a mapping defined by the likelihood function. Combining this with the maximum margin principle yields kernels for SVMs that leverage knowledge of the sensing model in an optimal way. We derive the optimum kernel for the bag-of-words (BoWs) sensing model and demonstrate its superior performance over other kernels in document and image classification tasks. These results indicate that such optimum sensing-aware kernel SVMs can match the performance of rather sophisticated state-of-the-art approaches.
COMPARISON OF L-H TRANSITION MEASUREMENTS WITH PHYSICS MODELS

A technique of fitting a modified hyperbolic tangent to the edge profiles has improved the localization of plasma edge parameters. Non-dimensional edge parameters are broadly consistent with several theories of the L-H transition that use edge gradients in their formulation of a critical threshold parameter. The ion ∇ B drift direction has only a small effect on the edge plasma conditions measured near the plasma midplane but a large effect on the divertor plasma. The dramatic change of power threshold with the ion ∇ B drift direction implies that phenomena in the divertor region may be critical for the L-H transition.
DISENTANGLING THE ORIGIN AND HEATING MECHANISM OF SUPERNOVA DUST: LATE-TIME SPITZER SPECTROSCOPY OF THE TYPE IIn SN 2005ip

This paper presents late-time near-infrared and Spitzer mid-infrared photometric and spectroscopic observations of warm dust in the Type IIn SN 2005ip in NGC 2906. The spectra show evidence for two dust components with different temperatures. Spanning the peak of the thermal emission, these observations provide strong constraints on the dust mass, temperature, and luminosity, which serve as critical diagnostics for disentangling the origin and heating mechanism of each component. The results suggest the warmer dust has a mass of approx. 5 x 10(exp -4) Solar Mass and originates from newly formed dust in the ejecta, continuously heated by the circumstellar interaction. By contrast, the cooler component likely originates from a circumstellar shock echo that forms from the heating of a large, pre-existing dust shell approx. 0.01 - 0.05 Solar Mass by the late-time circumstellar interaction. The progenitor wind velocity derived from the blue edge of the He I 1.083 micro P Cygni profile indicates a progenitor eruption likely formed this dust shell approx.100 years prior to the supernova explosion, which is consistent with a Luminous Blue Variable (LBV) progenitor star. Subject
Inversion of chalcogen defect levels in silicon: An MNDO study

MNDO (modified neglect of diatomic overlap) calculations have been carried out for substitutional oxygen and sulfur impurities in silicon. The calculations of the gap levels reveal a reversal of trend with atomic ionization energies in agreement with self-consistent Green function results, and analysis of the MNDO charge distribution supports the view that the electronegativity difference between oxygen and sulfur gives rise to this shallower energy level.
Two-stage acquisition for UWB in dense multipath

Traditional synchronization techniques applied to impulse-radio ultra-wideband (UWB) result in prohibitively long acquisition times, due to the extremely large search space. Additionally, in dense multipath environments, there exist a larger number of cells within the uncertainty region that can lead to acquisition lock. Locking to an arbitrary multipath component may result in unacceptable performance for many applications (range error in positioning systems for example). In this paper, we present a modified framework for the analysis of UWB acquisition which accommodates multiple lock cells. The framework divides the acquisition process into two distinct phases. The two phases are termed "coarse" and "fine" acquisition. The coarse acquisition phase is a fast implementation of traditional serial search which takes advantage of the large number of cells which can terminate the search process. Fine acquisition exploits statistics derived from the first phase and the clustered nature of multipath arrivals to determine the earliest arriving path, even when it is severely attenuated. We show that the first phase provides a substantial improvement in mean acquisition time compared with traditional serial search and that the second phase provides robust estimation of the first arriving path in ranging applications.
Carbon Dioxide Reduction via Homogeneous Catalytic Synthesis and Hydrogenation of N,N-Dimethylformamide.

Abstract : The previously reported catalytic reaction between CO2, H2, and (CH3)2NH to yield N,N-dimethylformamide (DMF) has been found to produce also trimethylamine (TMA) in the presence of several Ru, Os, Rh, Ir and Pt complexes. In separate experiments, the hydrogenation of DMF, catalyzed by the same or other complexes, also gave TMA. Thus, evidence is presented for the overall catalytic reduction of CO2 the the methyl group (-CH3, incorporated in TMA). Keywords: Carbon dioxide, Hydrogenation, Homogeneous catalysis, N, N Dimethylformamide, Ethyl radicals.
Global tectonics of Mercury and the moon

Lobate scarps on Mercury have been studied to determine the nature of the surface stress history and implications for the planet's early tectonic history. Morphologic and transection relations indicate that most Mercurian scarps are tectonic in nature and are due to compressive stresses in the surface layer. The azimuthal distribution of lobate-scarp trends is compatible with an early predominantly compressive global stress field due to thermal shrinkage of the planet. Superposition relations indicate that the contractive phase was largely a pre-Caloris process. The effects of stresses due to planetary despinning were either negligible, predate the scarps, or were largely obscured by cratering or volcanism. The tectonic history of Mercury as recorded in the lobate scarps is different from that which caused the system of lineaments on the moon.
Bottom-up Recognition and Parsing of the Human Body

Recognizing humans, estimating their pose and segmenting their body parts are key to high-level image understanding. Because humans are highly articulated, the range of deformations they undergo makes this task extremely challenging. Previous methods have focused largely on heuristics or pairwise part models in approaching this problem. We propose a bottom-up parsing of increasingly more complete partial body masks guided by a parse tree. At each level of the parsing process, we evaluate the partial body masks directly via shape matching with exemplars, without regard to how the parses are formed. The body is evaluated as a whole, not the sum of its constituent parses, unlike previous approaches. Multiple image segmentations are included at each of the levels of the parsing, to augment existing parses or to introduce ones. Our method yields both a pose estimate as well as a segmentation of the human. We demonstrate competitive results on this challenging task with relatively few training examples on a dataset of baseball players with wide pose variation. Our method is comparatively simple and could be easily extended to other objects.
An efficient and high yield method for the N-tert-butoxycarbonyl protection of sterically hindered amino acids

Abstract An improved method for the N - tert -butoxycarbonyl protection of the amino functionality of α-alkylated prolines and other sterically hindered α,α-disubstituted amino acids has been developed in which the lipophilic base tetramethylammonium hydroxide is used to solubilize the otherwise insoluble zwitterionic amino acid in acetonitrile, thereby obviating the need for an aqueous medium.
Sample Variance Considerations for Cluster Surveys

We present a general statistical framework for describing the effect of sample variance in the number counts of virialized objects and examine its effect on cosmological parameter estimation. Specifically, we consider effects of sample variance on the power spectrum normalization and properties of dark energy extracted from current and future local and high-redshift samples of clusters. We show that for future surveys that probe ever lower cluster masses and temperatures, sample variance is generally comparable to or greater than shot noise and thus cannot be neglected in deriving precision cosmological constraints. For example, sample variance is usually more important than shot variance in constraints on the equation of state of the dark energy from z < 1 clusters. Although we found that effects of sample variance on the σ8-Ωm constraints from the current flux- and temperature-limited X-ray surveys are not significant, they may be important for future studies utilizing the shape of the temperature function to break the σ8-Ωm degeneracy. We also present numerical tests clarifying the definition of cluster mass employed in cosmological modeling and an accurate fitting formula for the conversion between different definitions of halo mass (e.g., virial vs. fixed overdensity).
X-Ray variability of NLS1s and BLS1s

Abstract Evenly-sampled hard X-ray monitoring was obtained with RXTE for one NLS1 (Akn 564) and four BLS1s. The variability amplitude of the NLS1 was no larger than the mean of the BLS1s, and the NLS1 showed stronger variability in the harder portion of the RXTE band, while the BLS1s were more strongly variable in the relatively soft part of the band. This contribution discusses possible explanations for these surprising results, including possible calibration errors or systematic differences between long and short time scale variability in NLS1s and BLS1s.
A simple model for second breakdown

The analysis of second breakdown in transistors is very difficult when one takes into account the distributed nature of the transistor and the complex interactions of the charge carriers with the crystal lattice and with the various electric fields within the transistor. A simple model has recently been developed which can be analyzed in detail in terms of lumped transistor parameters. The model treats the transistor as though it consisted of two separate, but interacting, parts coupled thermally and electrically. All anamolous portions of the transistor are lumped into one of these. The relative importance of each of the initiating mechanisms which have been hypothesized for second breakdown can now be determined. This paper presents a brief static analysis of the model. Calculated static current-voltage characteristics are shown for some of the initiating mechanisms. The effect of the current dependence of current gain, the effect of the temperature dependence of the collector saturation current, and the effects of avalanche multiplication and its dependence on free charge carrier density will be discussed. It is concluded that all of these effects are important, but one or the other will tend to dominate depending on the transistor structure, type of defects present, and mode of operation. Experimental evidence of a change in the dominant mechanism during swept operation in second breakdown will be shown.
A reminder for language designers

Current programming languages offer limited support in the development and maintenance of programs. These languages do not always account for the human limitations of their users. Notably, few languages really promote ease of readability. This paper suggests nine design principles for the development of readable high level languages. Each principle is backed up by a discussion and several examples. Among the issues discussed are the limitation of the overall complexity, the design of function and procedure facilities, the design of data type facilities, and the correspondence between syntax and semantics.
Ballooning Modes in Thin Accretion Disks: Limits for Their Excitation

The conditions that limit the possible excitation of ideal MHD axisymmetric ballooning modes in thin accretion disks are discussed. As shown in 2001 by Coppi & Coppi, these modes are well localized in the vertical direction but have characteristic oscillatory and nonlocalized profiles in the radial direction. A necessary condition for their excitation is that the magnetic energy be considerably lower than the thermal energy. Even when this is satisfied, there remains the problem of identifying the possible physical factors that can make the considered modes radially localized. The general solution of the normal mode equation describing the modes is given, showing that it is characterized by a discrete spectrum of eigensolutions. The growth rates are reduced and have a different scaling relative to that of the "long-cylinder" modes, commonly known as the magnetorotational instability, that have been previously studied.