cssi/SciSciGPT-SciSciNet huggingface dataset:
Nickel-catalyzed cross-couplings of cyclohexenyl phosphate and arylboronic acids

The Nickel-catalyzed cross-coupling reaction of cyclohexenylphosphate with a variety of arylboronic acids is described here for the first time. This methodology opens the door to other palladium or nickel-catalyzed coupling reactions involving vinyl phosphates. Nickel-catalyzed cross-coupling reaction of cyclohexenyl phosphate with variety of arylboronic acids is reported here for the first time. Download full-size image
Removing even crossings on surfaces

In this paper we investigate how certain results related to the Hanani-Tutte theorem can be extended from the plane to surfaces. We give a simple topological proof that the weak Hanani-Tutte theorem is true on arbitrary surfaces, both orientable and non-orientable. We apply these results and the proof techniques to obtain new and old results about generalized thrackles, including that every bipartite generalized thrackle on a surface S can be embedded on S. We also extend to arbitrary surfaces a result of Pach and Toth that allows the redrawing of a graph so as to remove all crossings with even edges. From this we can conclude that cr"S(G), the crossing number of a graph G on surface S, is bounded by 2ocr"S(G)^2, where ocr"S(G) is the odd crossing number of G on surface S. Finally, we prove that ocr"S(G)=cr"S(G) whenever ocr"S(G)@?2, for any surface S.
A far- and mid-infrared study of HMX (octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine) under high pressure

Abstract We report two separate synchrotron FTIR measurements of the high explosive HMX at ambient temperature and static high pressure in the far- (100–500 cm −1 ) and mid- (500–3200 cm −1 ) infrared (IR) regions up to ∼30 GPa. The sample for the far-IR experiment was loaded with no pressure-transmitting medium and the sample for the mid-IR study utilized a KBr pressurizing medium. Two possible phase transitions were observed near 5 and 12 GPa (likely into the ∈ phase). A phase transition was observed near 25 GPa probably into the δ phase. Pressure cycling in both experiments found no irreversible damage within this pressure range.
Efficient learning algorithms yield circuit lower bounds

We describe a new approach for understanding the difficulty of designing efficient learning algorithms. We prove that the existence of an efficient learning algorithm for a circuit class C in Angluin's model of exact learning from membership and equivalence queries or in Valiant's PAC model yields a lower bound against C. More specifically, we prove that any subexponential time, deterministic exact learning algorithm for C (from membership and equivalence queries) implies the existence of a function f in EXP^N^P such that [email protected]?C. If C is PAC learnable with membership queries under the uniform distribution or exact learnable in randomized polynomial-time, we prove that there exists a function [email protected]?BPEXP (the exponential time analog of BPP) such that [email protected]?C. For C equal to polynomial-size, depth-two threshold circuits (i.e., neural networks with a polynomial number of hidden nodes), our result shows that efficient learning algorithms for this class would solve one of the most challenging open problems in computational complexity theory: proving the existence of a function in EXP^N^P or BPEXP that cannot be computed by circuits from C. We are not aware of any representation-independent hardness results for learning depth-2, polynomial-size neural networks with respect to the uniform distribution. Our approach uses the framework of the breakthrough result due to Kabanets and Impagliazzo showing that derandomizing BPP yields non-trivial circuit lower bounds.
Rock failure in compression

Abstract Mechanisms of rock failure in compression — axial splitting and shear failure — are studied, based on a microscopic consideration. Analytical models are constructed and model experiments on plates of a brittle polymer are performed. It is shown that unstable growth of tension cracks which propagate from the tips of pre-existing cracks and curve towards the maximum compressive direction, is the fundamental mechanism that produces axial splitting of a uniaxially compressed rock specimen, whereas shear failure of a triaxially compressed specimen is a result of sudden growth of tension cracks at tips of a suitably arranged interacting set of microcracks. The simultaneous out-of-plane unstable growth of a suitably oriented row of cracks is analyzed and, on the basis of this model, the variations of the “ultimate strength” and the orientation of the overall fault plane with the confining pressure are estimated. The brittle-ductile transition is discussed with the aid of a model which includes both tension crack extension and plastic zone development from the pre-existing cracks.
ORKA: The Golden Kaon Experiment

Abstract ORKA is a proposed experiment to measure the K + → μ + ν ν ¯ branching ratio with 5% precision using the Fermilab Main Injector high intensity proton source. The detector design is based on the BNL E787/E949 experiments, which detected seven K + → μ + ν ν ¯ candidate events. Two orders of magnitude improvement in sensitivity relative to the BNL experiments comes from enhancements to the beam line and the detector acceptance. Precise measurement of the K + → μ + ν ν ¯ branching ratio with the same level of uncertainty as the well-understood Standard Model prediction allows for sensitivity to new physics at and beyond the LHC mass scale.
Do government subsidies increase the private supply of public goods

We study three different models in which public goods are supplied by private contributions. In one of these models, tax-financed government subsidies to private contributions will definitely increase the equilibrium supply of public goods. In the other two models, government subsidies are neutralized by offsetting changes in private contributions. We explain why it is that these models lead to opposite conclusions and we argue on the basis of our first model that a government that wants to use taxes and subsidies to increase total provision of public goods will be able to do so. Indeed, our model yields a surprisingly decisive comparative statics result. If public goods and private goods are both normal goods, then an increase in the subsidy rate will necessarily increase the equilibrium supply of public goods.
20% Efficient screen-printed n-type solar cells using a spin-on source and thermal oxide/silicon nitride passivation

Due partly to the fact that n-type solar cells do not suffer from light-induced degradation, there has been a recent surge in research and industrial interest in n-type silicon solar cells. However, the most common dielectric materials that are used to passivate the surface of p-type cells — thermal oxide and silicon nitride — are well known to have problems with providing adequate passivation of heavily boron doped surfaces, especially on textured surfaces. As a result, the highest efficiency n-type cells have thus far relied on Al 2 O 3 whose high negative charge density results in good passivation on both planar and textured boron diffused surfaces. We show here that though thermal SiO 2 and SiN x alone provide poor passivation on p+ surfaces, a thin (15 nm) thermal-SiO 2 layer, capped with SiN x can, after firing, provide high-quality passivation on a textured, boron emitter. Firing at ∼ 750°C was found to result in a threefold improvement in the surface passivation quality with a final J 0 of ∼ 150 fA/cm2 being achieved. Additionally, a spin-on boric acid source was used to form a uniform, textured emitter as verified on completed solar cells which did not demonstrate junction shunting. Using a symmetric SiO 2 /SiN x stack passivation and screen-printed contacts, a verified n-type cell efficiency of 20.3% was achieved with V OC up to 650mV and J SC over 40mA/cm2. The stability of this structure was also tested, with no degradation being observed over 7 months of dark storage in air.
Laparoscopically assisted abdominal aortic aneurysm repair.

Improvements in anesthesia and surgical technique over the past 50 years have significantly lowered the morbidity and mortality rates associated with elective abdominal aortic aneurysm (AAA) repair. 23 But vascular surgeons are now more frequently encountering older patients with severe comorbid medical conditions, which can markedly increase operative mortality rates. Although nonresective therapies, such as thrombosis of the aneurysm or aortic ligation with axillofemoral bypass, have been suggested for use in high-risk patients, these techniques have not gained widespread acceptance because the procedures are not without risk and, even after transluminal thrombosis, rupture may occur. 22 A revolution of ideas and techniques has occurred in the vascular arena in response to aging, high-risk patients. In 1991, endovascular stenting of infrarenal AAAs emerged as a minimally invasive alternative to conventional repair in high-risk surgical patients. 21 After initial success in animals, Parodi 20 introduced the concept of repairing AAA with an endoprosthesis introduced into the aorta through the femoral arteries. To apply this technique in humans, he used a compliant Dacron (Cardiomedical, Rockaway, NJ) prosthesis attached to a Palmaz endoluminal stent (Johnson and Johnson, Warren, NJ). A 4-year experience review of Parodi's technique demonstrated that the procedure was associated with significant complications (e.g., graft migration, endoleaks, and thromboembolic events) and a substantial failure rate. The initial experience at Montefiore Medical Center (Bronx, NY) included 96 endovascular grafts implanted for complex arterial occlusive, traumatic, and aneurysmal lesions. 18 Technical and clinical success was achieved in that series in 91% of the patients with occlusive and aneurysmal lesions and in 100% of those with traumatic arterial lesions. Immediately after aneurysm exclusion, a total of six (33%) endoleaks were detected; three of those closed within 8 weeks. The major complication rate was 10% and the minor, 14%.
Landscape, the scale of SUSY breaking, and inflation

We argue that in the simplest version of the KKLT model, the maximal value of the Hubble constant during inflation cannot exceed the present value of the gravitino mass, Hm3/2. This may have important implications for string cosmology and for the scale of the SUSY breaking in this model. If one wants to have inflation on high energy scale, one must develop phenomenological models with an extremely large gravitino mass. On the other hand, if one insists that the gravitino mass should be O(1 TeV), one will need to develop models with a very low scale of inflation. We show, however, that one can avoid these restrictions in a more general class of KKLT models based on the racetrack superpotential with more than one exponent. In this case one can combine a small gravitino mass and low scale of SUSY breaking with the high energy scale of inflation.
SPATIAL NONLOCALITY OF THE SMALL-SCALE SOLAR DYNAMO

We explore the nature of the small-scale solar dynamo by tracking magnetic features. We investigate two previously explored categories of the small-scale solar dynamo: shallow and deep. Recent modeling work on the shallow dynamo has produced a number of scenarios for how a strong network concentration can influence the formation and polarity of nearby small-scale magnetic features. These scenarios have measurable signatures, for which we test using magnetograms from the Narrowband Filter Imager (NFI) on board Hinode. We find no statistical tendency for newly formed magnetic features to cluster around or away from network concentrations, nor do we find any statistical relationship between their polarities. We conclude that there is no shallow or "surface" dynamo on the spatial scales observable by Hinode/NFI. In light of these results, we offer a scenario in which the subsurface field in a deep solar dynamo is stretched and distorted via turbulence, allowing the small-scale field to emerge at random locations on the photosphere.
Implementation of quality control in software development

In recent years, many tools have been developed in the areas of programming techniques, design methodology, development processes, and test strategies. All of these are aimed at producing a quality product with a minimum cost. Together with emergence of these tools, there is a recognition of the problem of how to effectively implement them into a total systems development environment. One of the factors to a successful development is the ability to exercise proper control over the various development processes.We will first establish the objectives for software quality control. Then, descriptions of the terminologies defining the various development processes will be presented in order to provide a common background. A basic philosophy of the entire development procedure and the notion of Continuous Integration will be presented. The introduction of quality control into this procedure will be discussed. Finally, some justification for such an approach will be shown.
The Origin of the Local Bubble

The Sun is located in a low-density region of the interstellar medium partially filled with hot gas that is the likely result of several nearby supernova explosions within the last 10 Myr. Here we use astrometric data to show that part of the Scorpius-Centaurus OB association was located closer to the present position of the Sun 5-7 Myr ago than today. Evolutionary synthesis models indicate that the association must have experienced ~20 supernova explosions in the last 10-12 Myr, a prediction that is supported by the detection of four or five runaway stars escaping from it. The approximately six supernovae produced by the Lower Centaurus Crux subgroup are likely responsible for the creation of the Local Bubble.
Exploring early parton momentum distribution with the ridge from the near-side jet

In a central nucleus-nucleus collision at high energies, medium partons kicked by a near-side jet acquire a momentum along the jet direction and subsequently materialize as the observed ridge particles. They carry direct information on the early parton momentum distribution which can be extracted by using the ridge data for central AuAu collisions at √s NN = 200 GeV. The extracted parton momentum distribution has a thermal-like transverse momentum distribution but a non-Gaussian, relatively flat rapidity distribution at mid-rapidity with sharp kinematic boundaries at large rapidities that depend on the transverse momentum.
Outlook for controlled fusion power.

Fission and fusion are compared as a source of energy for the future. Energy reserves for the two are similar, as are their pollution and ecological characteristics. A remote integrated site policy is recommended for fission.
Endogenous fertility and growth in a model with old age support

This paper examines the interrelationship between capital accumulation, fertility, and growth by introducing an endogenous fertility decision into Diamond's (1965) neoclassical growth model. Under the assumptions that children provide old age support and that individuals incur a variable time cost of raising children, it investigates the potential for cyclical fluctuations in the capital-labor ratio and fertility, as well as for development trap phenomena to be observed. It is shown that when capital and labor are highly substitutable in production, there is a unique steady state equilibrium, and either damped or undamped oscillations in fertility and the capital-labor ratio may occur. However, when the elasticity of substitution between capital and labor is less than one, two steady state equilibria may exist; one with a high capital-labor ratio and a high rate of population growth, and the other with a lower capital-labor ratio as well as a lower population growth rate. The former is a saddle, while the latter may be either a source or a sink. In the latter case development traps are possible.
Technology structural implications from the extension of a patent search method

Many areas of academic and industrial work make use of the notion of a `technology'. This paper attempts to reduce the ambiguity around the definition of what constitutes a `technology' by extension of a method described previously that finds highly relevant patent sets for specified technological fields. The method relies on a less ambiguous definition that includes both a functional component and a component consisting of the underlying knowledge in a technological field to form a two-component definition. These two components form a useful definition of a technology that allows for objective, repeatable and thus comparable analysis of specific technologies. 28 technological domains are investigated: the extension of an earlier technique is shown to be capable of finding highly relevant and complete patent sets for each of the technologies. Overall, about 500,000 patents from 1976 to 2012 are classified into these 28 domains. The patents in each of these sets are not only highly relevant to the domain of interest but there are relatively low numbers of patents classified into any two of these domains (total patents classified in two domains are 2.9 % of the total patents and the great majority of patent class pairs have zero overlap with a few of the 378 patent class pairs containing the bulk of the doubly listed patents). On the other hand, the patents within a given domain cite patents in other domains about 90 % of the time. These results suggest that technology can be usefully decomposed to distinct units but that the inventions in these relatively tightly contained units depend upon widely spread additional knowledge.
Electrochemical regeneration of clean and well-ordered Pd(111) surfaces

In this paper, we suggest a new procedure for the electrochemical or in situ regeneration of clean and well-ordered electrode surfaces. All the steps in this method, which is demonstrated here for a Pd(111) single-crystal electrode, are performed inside the electrochemical cell
Investigation of the Rotor Demagnetization Characteristics of Interior PM Synchronous Machines During Fault Conditions

This paper investigates the transient magnetic behavior of an interior permanent-magnet (IPM) synchronous machine following a large transient current caused by a fault condition. A combination of finite-element (FE) analysis and numerical integration of the machine equations is used to calculate the currents resulting from a symmetrical three-phase short-circuit fault at the machine terminals, including magnetic saturation effects. FE analysis is further used to simulate the magnetic behavior of the machine when subjected to the fault currents, with a particular focus on the propagation of the demagnetizing MMF throughout the conductive laminations as well as the conductive PM material. Eddy currents induced in the laminations and magnet material are shown to impede the progression of the demagnetizing MMF. However, the transient analysis illustrates the manner in which the fault currents ultimately trigger the onset of irreversible demagnetization of significant portions of the rotor magnets in the analyzed machine. The transient demagnetization analysis method is extended to investigate the influence of several key design variables, including machine operating temperature and segmentation of the rotor magnets.
A nonlinear theory of cosmic-ray pitch-angle diffusion in homogeneous magnetostatic turbulence

A plasma strong turbulence, weak coupling, theory is applied to the problem of cosmic-ray pitch-angle scattering in magnetostatic turbulence. The theory used is a rigorous generalization of Weinstock's 'resonance broadening' theory and contains no ad hoc approximations. A detailed calculation is presented for a model of 'slab' turbulence with an exponential correlation function. The results agree well with numerical simulations. The rigidity dependence of the pitch-angle scattering coefficient differs from that found by previous researchers. The differences result from an inadequate treatment of particle trajectories near 90 deg pitch angle in earlier work.
Quasitransient regimes of backward Raman amplification of intense x-ray pulses

New powerful soft x-ray sources may be able to access intensities needed for backward Raman amplification (BRA) of x-ray pulses in plasmas. However, high plasma densities, needed to provide enough coupling between the pump and seed x-ray pulses, cause strong damping of the Langmuir wave that mediates energy transfer from the pump to the seed pulse. Such damping could reduce the coupling, thus making efficient BRA impossible. This work shows that efficient BRA can survive despite the Langmuir wave damping significantly exceeding the linear BRA growth rate. Moreover, the strong Langmuir wave damping can automatically suppress deleterious instabilities of BRA to the thermal noise. The class of "quasitransient" BRA regimes identified here shows that it may be feasible to observe x-ray BRA within available x-ray facilities.
Feasibility of Oral Topotecan Plus Intravenous Paclitaxel in Advanced Non-Small-Cell Lung Cancer

Standard chemotherapy regimens in non-small-cell lung cancer (NSCLC) are platinum-based (cisplatin, carboplatin), with inherent, well-known antitumor activity and toxicity. However, the availability of new agents with novel mechanisms of action and activity in a range of tumor types, coupled with suboptimal activity of single-agent therapy, have prompted the investigation of multidrug regimens in the treatment of NSCLC. One potential combination regimen, in which each agent has antitumor activity in NSCLC monotherapy, is topotecan plus paclitaxel. This article will review the feasibility and tolerability of an oral formulation of topotecan (1.0-1.5 mg/m(2)/day x 5 days) administered with intravenous paclitaxel (175 mg/m(2) as a 3-hour infusion on day 1) in advanced NSCLC patients. The maximum tolerated dose of oral topotecan will be reported, along with preliminary response and tolerability data.
Lower bounds on communication complexity in distributed computer networks

The main result of this paper is a general technique for determining lower bounds on the communication complexity of problems on various distributed computer networks. This general technique is derived by simulating the general network by a linear array and then using a lower bound on the communication complexity of the problem on the linear array. Applications of this technique yield optimal bounds on the communication complexity of merging, ranking, uniqueness, and triangle-detection problems on a ring of processors. Nontrivial near-optimal lower bounds on the communication complexity of distinctness, merging, and ranking on meshes and complete binary trees are also derived.
Amino Acid Catalyzed Direct Asymmetric Aldol Reactions: A Bioorganic Approach to Catalytic Asymmetric Carbon-Carbon Bond-Forming Reactions

Direct asymmetric catalytic aldol reactions have been successfully performed using aldehydes and unmodified ketones together with commercially available chiral cyclic secondary amines as catalysts. Structure-based catalyst screening identified l-proline and 5,5-dimethyl thiazolidinium-4-carboxylate (DMTC) as the most powerful amino acid catalysts for the reaction of both acyclic and cyclic ketones as aldol donors with aromatic and aliphatic aldehydes to afford the corresponding aldol products with high regio-, diastereo-, and enantioselectivities. Reactions employing hydroxyacetone as an aldol donor provide anti-1,2-diols as the major product with ee values up to >99%. The reactions are assumed to proceed via a metal-free Zimmerman−Traxler-type transition state and involve an enamine intermediate. The observed stereochemistry of the products is in accordance with the proposed transition state. Further supporting evidence is provided by the lack of nonlinear effects. The reactions tolerate a small amount o...
Structural trans effects in some bis(ethylenediamine)cobalt(III) complexes

Abstract The crystal structures of seven bis(ethylenediamine) cobalt(III) complexes with monodentate oxalato, azido, nitro, sulfito and thiosulfato ligands have been determined by single-crystal X-ray diffraction methods. The complexes, space groups, cell constants, number of molecules per unit cell, Z , calculated and experimental densities and final reliability factors are as follows: cis [en 2 Co(NO 2 )- (C 2 O 4 )]·2H 2 O, P 1 , a = 6.925(3), b = 8.055(3), c = 12.158(4)A, α = 80.16(2)°, β = 77.87(2)°, γ= 87.90(2)°, V = 653 A 3 Z = 2, ϱ exp = 1.78 g cm −3 , ϱ calc = 1.76 g cm −3 , R 1 = 5.5, R 2 = 9.4; trans [en 2 - Co(NO 2 )(C 2 O 4 )]·2H 2 O, P 2 1 / n , a = 8.218(2), b = 15.613(1), c = 10.694(1) A, β = 101.49(1)°, V = 1344 A 3 , Z = 4, ϱ exp = 1.73 g cm −3 , ϱ calc = 1.74 g cm −3 , R 1 = 3.5, R 2 = 5.6; cis [en 2 Co(N 3 )(C 2 O 4 )]· H 2 O, P 2 1 / c , a = 8.379(1), b = 15.548(4), c = 9.736(3) A, β = 97.44(2)°, V = 1258 A 3 , Z = 4, ϱ exp = 1.73 g cm −3 ϱ calc = 1.69 g cm −3 , R 1 = 4.3, R 2 = 4.8; trans [en 2 Co(N 3 )(C 2 O 4 )]·2H 2 O, I 4 1 / a , a = 26.684(2), c = 7.625(2) A, V = 5429 A 3 , Z = 16,ϱ exp = 1.69 g cm −3 , ϱ calc = 1.69 g cm −3 , R 1 = 6.6, R 2 = 7.9; cis -NH 4 [en 2 Co(S 2 O 3 )(SO 3 )]·3H 2 O, P 2 1 / n , a = 10.094(9), b = 12.205(12), c = 13.358(3) A, β = 90.19(4)°, V = 1646 A 3 , Z = 4, ϱ exp = 1.79 g cm −3 , ϱ calc = 1.78 g cm −3 , R 1 = 7.6, R 2 = 9.2; cis [en 2 - Co(N 3 )(SO 3 )]·1.5H 2 O, P 2 1 / n , a = 7.749(1), b = 10.701(2), c = 15.101(4) A, β = 102.80(2)°, V = 1221 A 3 , Z = 4, ϱ exp = 1.78 g cm −3 , ϱ calc = 1.78 g cm −3 , R 1 = 3.2, R 2 = 4.0; cis [en 2 Co(NO 2 )(SO 3 )]· 1H 2 O, P 2 1 / c , a = 6.629(2), b = 11.429(4), c = 15.156(4) A, β = 93.27(2)°, V = 1146 A 3 , Z = 4, ϱ exp = 1.87 g cm −3 , ϱ calc = 1.86 g cm −3 , R 1 = 3.5, R 2 = 4.4. Additionally, the previously reported structure of cis [en 2 Co(N 3 ) 2 ]NO 3 has been redetermined: Pnma , a =11.903(3), b =23.566(6), c = 8.877(2) A, V = 2493 A 3 , Z = 8, ϱ exp = 1.73 g cm −3 , ϱ calc = 1.73 g cm −3 , R 1 = 4.8, R 2 = 5.9. The structural trans effect, STE , the difference between the CoN(en) bond length trans to a ligand and the average of the two CoN(en) bond lengths that are both cis to that ligand and trans to each other, decreases in the series SO 3 2− [0.059(7) A]> SSO 3 2− [0.036(9) A]> NO 2 − [0.019 (10) A]> N 3 − [0.005(6) A]> C 2 O 4 2− [0.000(6) A].
A Moving Cold Front in the Intergalactic Medium of A3667

We present results from a Chandra observation of the central region of the galaxy cluster A3667 with emphasis on the prominent sharp X-ray brightness edge spanning 0.5 Mpc near the cluster core. Our temperature map shows large-scale nonuniformities characteristic of the ongoing merger, in agreement with earlier ASCA results. The brightness edge turns out to be a boundary of a large cool gas cloud moving through the hot ambient gas, very similar to the "cold fronts" discovered by Chandra in A2142. The higher quality of the A3667 data allows the direct determination of the cloud velocity. At the leading edge of the cloud, the gas density abruptly increases by a factor of 3.9 ± 0.8, while the temperature decreases by a factor of 1.9 ± 0.2 (from 7.7 to 4.1 keV). The ratio of the gas pressures inside and outside the front shows that the cloud moves through the ambient gas at near-sonic velocity, M = 1 ± 0.2 or v = 1400 ± 300 km s-1. In front of the cloud, we observe the compression of the ambient gas with an amplitude expected for such a velocity. A smaller surface brightness discontinuity is observed further ahead, ~350 kpc in front of the cloud. We suggest that it corresponds to a weak bow shock, implying that the cloud velocity may be slightly supersonic. Given all the evidence, the cold front appears to delineate the remnant of a cool subcluster that recently has merged with A3667. The cold front is remarkably sharp. The upper limit on its width, 35 or 5 kpc, is several times smaller than the Coulomb mean free path. This is a direct observation of suppression of the transport processes in the intergalactic medium, most likely by magnetic fields.
Near-Infrared and Optical Limits for the Central X-Ray Point Source in the Cassiopeia A Supernova Remnant*

We set new near-infrared and optical magnitude limits for the central X-ray point source (XPS) in the Cassiopeia A supernova remnant based on HST images. Near-infrared images of the center of Cas A taken with the NICMOS 2 camera in combination with the F110W and F160W filters (~J and H bands) have magnitude limits ≥26.2 and ≥24.6, respectively. These images reveal no sources within a 12 radius (corresponding to a 99% confidence limit) of the Chandra XPS position. The NICMOS data, taken together with broadband optical magnitude limits (R ~ 28 mag) obtained from a deep STIS CCD exposure taken with a clear filter (50CCD), indicate that the XPS luminosities are very low in the optical/NIR bands (e.g., LH < 3 × 1029 ergs s-1) with no optical, J-, or H-band counterpart to the XPS easily detectable by HST. The closest detected object lies 18 from the XPS's nominal coordinates, with magnitudes R = 25.7, mF110W = 21.9, and mF160W = 20.6, and is a foreground, late-type star as suggested by Kaplan, Kulkarni, and Murray. We discuss the nature of the Cas A central compact object on the basis of these near-infrared and optical flux limits.
Influence of fuel temperature on atomization performance of pressure-swirl atomizers

The influence of fuel temperature on mean drop size and drop-size distribution is examined for aviation gasoline and diesel oil using three pressure-swirl simplex nozzles. Spray characteristics are measured over wide ranges of fuel injection pressure and ambient air pressure using a Malvern spray analyzer. Fuel temperatures are varied from 20+ 50°C. Over this range of temperature, the overall effect of an increase in fuel temperature is to reduce the mean drop size and broaden the drop-size distribution in the spray. Generally, it is found that the influence of fuel temperature on mean drop size is far more pronounced for diesel oil than for gasoline. For both fuels, the beneficial effect of higher fuel temperatures on atomization quality is sensibly independent of ambient air pressure.
Holographic microantenna array metrology

We describe a holographic or "phaseless" technique for measurement of complex antenna patterns that is particularly suited to planar antennas at very high frequencies (mm-wave thru long-wave infrared) where phase coherent detection is impractical. It has been implemented in a compact automated antenna range, and validated on a previously reported planar slot-ring antenna at 95 GHz. In the IR, the interferometric technique must be refined in order to reduce to acceptable levels the uncertainties due to positioning and alignment errors. This measurement of the complex antenna pattern is the most problematic part of a full accounting for the optical coupling efficiency "budget" in a microantenna-coupled, imaging sensor array.
Stereoselective, Lewis acid-catalyzed glycosylation of alcohols by glucose 1,2-cyclic sulfites

Abstract α- d -Glucopyranose-1,2-cyclic sulfites ( 1a–c ) have been prepared by reaction of a suitably protected glucose residue and thionyl diimidazole. Reaction of these compounds with alcohols in the presence of Yb(OTf) 3 or Ho(OTf) 3 stereoselectively affords β-O-glycosides.
Ground states in non-relativistic quantum electrodynamics

The excited states of a charged particle interacting with the quantized electromagnetic field and an external potential all decay, but such a particle should have a true ground state — one that minimizes the energy and satisfies the Schrodinger equation. We prove quite generally that this state exists for all values of the fine-structure constant and the ultraviolet cutoff. We also show the same thing for a many-particle system under physically natural conditions.
Mechanisms involved in the biosynthesis of polysaccharides

The mechanisms for the biosynthesis of three polysaccharides are presented: (i) starch synthesized by starch synthase and adenosine diphospho glucose; (ii) dextran synthesized by Leuconostoc mesenteroides B-512FMC dextransucrase and sucrose; and (iii) Acetobacter xylinum cellulose synthesized by cellulose synthase, uridine diphospho glucose, and bactoprenol phosphate. All three enzymes were pulsed with substrates, containing 14C-glucose and chased with the same nonlabeled substrates. When the polysaccharides were isolated, reduced, and hydrolyzed, the pulsed reactions gave 14C-glucitol, which was significantly decreased in the chase reaction. These experiments definitively show that all three polysaccharides are biosynthesized by the addition of glucose to the reducing-ends of the growing polysaccharides and not by the addition to the nonreducing-ends of primers. Additional evidence indicates that glucose and the polysaccharides are covalently attached to the active-sites of the enzymes. A two catalytic-site insertion mechanism at one active-site is proposed for the biosyntheses. Two of the polysaccharides are α-linked glucans, starch and dextran, and cellulose is a β-linked glucan, known for several years to require a bactoprenol lipid phosphate intermediate. It is shown how this intermediate is involved in determining that β-linkages are synthesized. Other β-linked polysaccharides: bacterial cell wall peptidomurein, Salmonella O-antigen polysaccharide, and Xanthanomonas camprestris xanthan, are heteropolysaccharides, with the later two also being hetero-linked polysaccharides, with the β-linkage at the reducing-end of the repeating unit. All three require bactoprenol lipid phosphate intermediates and are biosynthesized by the addition of the repeating units to the reducing-end of a growing polysaccharide chain, with the formation of a β-linkage.
The role of economists in public policy

Abstract Improving the economic condition of society is the long-run goal of economics, although few academic economists or financial economists get involved in public policy activities. In large measure, this reflects the strong bias the profession has in favor of quantitative and theoretical skills and contributions. But this is not all bad, as good policy decisions are based on a good grounding in theory and method. However, economists having these attributes should and could actively look for ways to apply them to public policy issues, if they so wish.
Fourier transform microwave spectroscopy of chemical-warfare agents and their synthetic precursors

Fourier-transform microwave (FTMW) spectroscopy is an established is an established technique for observing the rotational spectra of molecules and complexes in molecular beams. Scientists at the National Institute of Standards and Technology (NIST) are adapting this measurement technology for applications in analytical chemistry. Presently, FTMW spectroscopy is being used to investigate chemical-warfare agents and their synthetic precursors. A FTMW spectroscopy facility has been established at a surety laboratory at the Edgewood Research, Development, and Engineering Center, where the capabilities exist for handling these deadly warfare agents. Here, the rotational spectra of Sarin, Soman and DF have been observed and assigned. Also, microwave spectroscopic studies of less toxic precursors such as pinacolyl alcohol, isopropyl alcohol, and thiodiglycol have been carried out at NIST. Tests will be undertaken to assess the potential of using FTMW spectroscopy for detecting trace amounts of chemical-warfare agents and precursors in air. A database of rotational transition frequencies is being compiled for use in conjunction with a FTMW spectrometer to unambiguously detect and monitor chemical weapons. The sensitivity and resolution of FTMW spectroscopy of FTMW spectroscopy suggest that the technique may offer real-time, unequivocal identification of chemical-warfare agents at trace vapor concentrations in air.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
On the Noncommutative Residue and the Heat Trace Expansion on Conic Manifolds

Given a cone pseudodifferential operator P we give a full asymptotic expansion as t → 0 + of the trace Tr Pe -tA , where A is an elliptic cone differential operator for which the resolvent exists on a suitable region of the complex plane. Our expansion contains log t and new (log t)2 terms whose coefficients are given explicitly by means of residue traces. Cone operators are contained in some natural algebras of pseudodifferential operators on which unique trace functionals can be defined. As a consequence of our explicit heat trace expansion, we recover all these trace functionals.
Theoretical Studies of the Flux and Energy Spectrum of Gamma Radiation from the Sun

The purpose of this work is to study the various γ-ray-production mechanisms in solar flares and to calculate the flux, the spectrum, and the decay curves of γ radiation. Using the continuity equation and taking into account the energy losses for solar-flare-accelerated particles, we obtain the time-dependent particle distribution and thus the time behavior of the resulting γ rays. The important processes for producing γ rays in solar flares are found to be nonthermal electron bremsstrahlung, decay of neutral π mesons, positron annihilation, neutron capture, and decay of excited nuclei. The results are applied to several known solar flares. For a large flare such as the class 3+ on February 23, 1956, continuous γ rays with energies up to 100 MeV from electron bremsstrahlung and neutral π meson decays are observable at the orbit of the Earth by existing γ-ray detectors. Line γ rays from positron annihilation (0.51 MeV), neutron capture (2.23 MeV), and deexcitation of excited nuclei O16 (6.14 and 7.12 MeV) and C12 (4.43 MeV) are particularly strong and well above the continuous γ-ray background due to electron bremsstrahlung. These lines can be detected at the Earth.
Gauge Theory Correlators from Non-Critical String Theory

Abstract We suggest a means of obtaining certain Green's functions in 3+1-dimensional N =4 supersymmetric Yang-Mills theory with a large number of colors via non-critical string theory. The non-critical string theory is related to critical string theory in anti-deSitter background. We introduce a boundary of the anti-deSitter space analogous to a cut-off on the Liouville coordinate of the two-dimensional string theory. Correlation functions of operators in the gauge theory are related to the dependence of the supergravity action on the boundary conditions. From the quadratic terms in supergravity we read off the anomalous dimensions. For operators that couple to massless string states it has been established through absorption calculations that the anomalous dimensions vanish, and we rederive this result. The operators that couple to massive string states at level n acquire anomalous dimensions that grow as 2 ng YM 2N 1/2 for large `t Hooft coupling. This is a new prediction about the strong coupling behavior of large N SYM theory.
Active manganese dioxide on silica: Oxidation of alcohols under solvent-free conditions using microwaves

Abstract Alcohols are rapidly and selectively oxidized to the corresponding carbonyl compounds by silica supported active manganese dioxide under solvent-free conditions using microwaves.
Effect of boundary layer thickness on secondary structures in a short inlet curved duct

Abstract The flow pattern in short inlet ducts with aggressive curvature has been shown to lead, in some cases, to an asymmetric flow field at the aerodynamic interface plane. In the present work, a two-dimensional honeycomb mesh was added upstream of the curved duct to create a pressure drop across it, and therefore to an increased velocity deficit in the boundary layer. This velocity deficit led to a stronger streamwise separation, overcoming the instability that can result in an asymmetric flow field at the aerodynamic interface plane. Experiments were conducted at Mach numbers of M = 0.2, 0.44 and 0.58 in an expanding aggressive duct with rectangle to a square cross section with area ratio of 1.27. Steady and unsteady pressure measurements, together with Particle Image Velocimetry (PIV), were used to explore the effect of the honeycomb on the symmetry of the flow field. The effect of inserting a honeycomb was tested by increasing its height from 0 to 2.2 times the boundary layer thickness of the baseline flow upstream of the curve. Using the honeycomb, flow symmetry was achieved for the specific geometrical configuration tested with a negligible decrease of the pressure recovery.
AIDS mortality and its effect on the labor market: Evidence from South Africa ☆

Abstract This paper investigates how HIV/AIDS has impacted the labor market in South Africa, focusing on its effect on wages and employment. This is done by matching individual level data with group specific cumulative AIDS mortality rates. Exploiting the panel nature of the data, I remove individuals whose productivity is most likely impacted by HIV/AIDS, and find evidence that cumulative AIDS mortality has led to reductions in wages of between 3 and 6% for the African population group (Black South Africans). Furthermore, I also find evidence that the epidemic has lowered employment in South Africa. This result is concentrated among those with the lowest levels of education and employment. Although not large in magnitude, these effects are widespread across a significant portion of the population, contributing to a substantial loss of income throughout the South African economy.
Financial stability and Basel II

The Basel II Advanced Internal Ratings (AIRB) approach is compared to capital requirements set using an equilibrium structural credit risk model. Analysis shows the AIRB approach undercapitalizes credit risk relative to regulatory targets and allows wide variation in capital requirements for a given exposure owing to ambiguity in the definitions of loss given default and exposure at default. In contrast, the Foundation Internal Ratings Based (FIRB) approach may over-capitalize credit risk relative to supervisory objectives. It is unclear how Basel II will buttress financial sector stability as it specifies the weakest regulatory capital standard for large complex AIRB banks.
British Industrialization before 1841: Evidence of Slower Growth during the Industrial Revolution

New indices of industrial production show that Britain's industrial growth in the last decades of the eighteenth century and the first decades of the nineteenth century was about a third slower than currently available estimates indicate. Therefore, mid-eighteenth-century industrial output was nearly twice as high as previously assumed.
A Design Point Correlation for Losses due to Part-Span Dampers on Transonic Rotors

The design-point losses caused by part-span dampers were correlated for 21 transonic axial-flow fan rotors that had tip speeds varying from 350 to 488 meters per second and design pressure ratios of 1.5 to 2.0. The additional loss attributable to the damper and the total region along the blade height influenced were correlated with selected aerodynamic and geometric parameters. The maximum damper loss correlated well with the mean inlet Mach number at the damper location, the geometric parameters of leading- and trailing-edge damper radius normalized by mean passage height and damper aerodynamic chord, respectively, and the aerodynamic loading parameter of the blade camber divided by the solidity at the damper location. The region of damper influence extended over a mean passage height of the order of 10 to 15 times the maximum damper thickness.
Fabrication and characterization of vertical travel linear microactuator

This paper describes design, fabrication and characterization of a proof-of-concept vertical travel linear microactuator designed to provide out-of-plane actuation for high precision positioning applications in space. The microactuator is designed to achieve vertical actuation travel by incorporating compliant beam structures within a SOI (Silicon on Insulator) wafer. Device structure except for the piezoelectric actuator is fabricated on the SOI wafer using Deep Reactive Ion Etch (DRIE) process. Incremental travel distance of the piezoelectric actuator is adjustable at nanometer level by controlling voltage. Bistable beam geometry is employed to minimize initial gaps between electrodes. The footprint of an actuator is approximately 2 mm x 4 mm. Actuation is characterized with LabVIEW-based test bed. Actuation voltage sequence is generated by the LabVIEW controlled power relays. Vertical actuation in the range of 500 nm over 10-cycle was observed using WYKO RST Plus Optical Profiler.
Harmonic scalpel versus flexible CO2 laser for tongue resection: A histopathological analysis of thermal damage in human cadavers

Background: Monopolar cautery is the most commonly used surgical cutting and hemostatic tool for head and neck surgery. There are newer technologies that are being utilized with the goal of precise cutting, decreasing blood loss, reducing thermal damage, and allowing faster wound healing. Our study compares thermal damage caused by Harmonic scalpel and CO2 laser to cadaveric tongue. Methods: Two fresh human cadaver heads were enrolled for the study. Oral tongue was exposed and incisions were made in the tongue akin to a tongue tumor resection using the harmonic scalpel and flexible C02 laser fiber at various settings recommended for surgery. The margins of resection were sampled, labeled, and sent for pathological analysis to assess depth of thermal damage calculated in millimeters. The pathologist was blinded to the surgical tool used. Control tongue tissue was also sent for comparison as a baseline for comparison. Results: Three tongue samples were studied to assess depth of thermal damage by harmonic scalpel. The mean depth of thermal damage was 0.69 (range, 0.51 - 0.82). Five tongue samples were studied to assess depth of thermal damage by CO2 laser. The mean depth of thermal damage was 0.3 (range, 0.22 to 0.43). As expected, control samples showed 0 mm of thermal damage. There was a statistically significant difference between the depth of thermal injury to tongue resection margins by harmonic scalpel as compared to CO2 laser, (p = 0.003). Conclusion: In a cadaveric model, flexible CO2 laser fiber causes less depth of thermal damage when compared with harmonic scalpel at settings utilized in our study. However, the relevance of this information in terms of wound healing, hemostasis, safety, cost-effectiveness, and surgical outcomes needs to be further studied in clinical settings.
A systematic incrementalization technique and its application to hardware design

A systematic transformation method based on incrementalization and value caching generalizes a broad family of program optimizations. It yields significant performance improvements in many program classes, including iterative schemes that characterize hardware specifications. CACHET is an interactive incrementalization tool. Although incrementalization is highly structured and automatable, better results are obtained through interaction, where the main task is to guide term rewriting based on data-specific identities. Incrementalization specialized to iteration corresponds to strength reduction, a familiar program improvement technique. This correspondence is illustrated by the derivation of a hardware-efficient nonrestoring square-root algorithm, which has also served as an example of theorem prover-based implementation verification.