cssi/SciSciGPT-SciSciNet huggingface dataset:
The Optimal Time Path for Carbon Abatement and Carbon Sequestration under Uncertainty: The Case of Stochastic Targeted Stock

Abstract We explore the optimal time path of carbon sequestration and carbon abatement in stabilizing CO2 levels under uncertainty of climate impacts. Using a two-period sequential decision making model, we analytically derive optimal rates for the two control variables, abatement and sequestration rates. Uncertainty is assumed to affect the desired future stabilization level of the CO2 stock but is resolved prior to the decision on how much to control the stock in the second period. Contrary to recent numerical studies, we find that uncertainty can make it optimal to use carbon sequestration either earlier or later depending on the relative rates of change in both marginal cost curves and on the amount of land that can be converted to forest. Comparative statics suggest that an increase in the discount factor could either increase or decrease the optimal rate of sequestration in the first period depending on the expected rate of change of the marginal cost of sequestration in the second period and on future benefits of current sequestration.
Nonlinear Recursive Filter for Boost Trajectories

A nonlinear recursive algorithm is formulated for state vector and covariance estimation of boost trajectories. The thrust acceleration vector of the booster is modeled by a vector-differential equation that includes effects of propellant depletion and attitude motions resulting from gravity-turn maneuvers and other steering maneuvers. This new dynamicsmodel is incorporated in an extended Kalman  lter with nine state variables that describe the inertial components of position, velocity, and thrust acceleration. Additional algorithms are described for  lter initialization using angle-only measurements from a geostationary sensor and for detection and estimation of the  nal staging event using measurement residuals. Tracking accuracy and covariance  delity are assessed byMonte Carlo simulation.
A topological approach to evasiveness

The complexity of a digraph property is the number of entries of the vertex adjacency matrix of a digraph which must be examined in worst case to determine whether the graph has the property. Rivest and Vuillemin proved the result (conjectured by Aanderaa and Rosenberg) that every graph property that is monotone (preserved by addition of edges) and nontrivial (holds for some but not all graphs) has complexity Ω(v 2) wherev is the number of vertices. Karp conjectured that every such property is evasive, i.e., requires that every entry of the incidence matrix be examined. In this paper the truth of Karp’s conjecture is shown to follow from another conjecture concerning group actions on topological spaces. A special case of the conjecture is proved which is applied to prove Karp’s conjecture for the case of properties of graphs on a prime power number of vertices.
REGIOSELECTIVE SYNTHESIS OF ACYCLOVIR AND ITS VARIOUS PRODRUGS

High-yield regioselective synthesis of 9-[(2-hydroxyethoxy) methyl]guanine (Acyclovir 1, Scheme 1) was achieved from guanine via trisilylated guanine. N 2-acylacyclovir 9a–9b were prepared from N 2, O-diacylacyclovir (4, 8b–8d) using regioselective deacylation procedure. N 2- Acylacyclovir 11 and 13 were prepared via protection of primary hydroxyl groups. Three amino acid esters of acyclovir were synthesized as water-soluble prodrugs, which form protonated cations in pH 7.4 phosphate buffer. Two water-soluble ester prodrugs with free carboxylic acids, which form anionic species in pH 7.4 phosphate buffer, were also synthesized. 10.1081/SCC-100104050-SCH0001 Scheme 1. Reagents and conditions: i. acetic anhydride, HOAc, DMAP, 160°C, 8 h, 3: 88%; ii. P-TsOH, 1,3-dioxolane, Ac2O, HOAc; then, toluene, relfux, 1 h, 4: 18%; 5: 2.3%; 4 and 5: 52%; iii. 40% aqueous CH3NH2, 1: 93%.
Krylov subspaces associated with higher-order linear dynamical systems

A standard approach to model reduction of large-scale higher-order linear dynamical systems is to rewrite the system as an equivalent first-order system and then employ Krylov-subspace techniques for model reduction of first-order systems. This paper presents some results about the structure of the block-Krylov subspaces induced by the matrices of such equivalent first-order formulations of higher-order systems. Two general classes of matrices, which exhibit the key structures of the matrices of first-order formulations of higher-order systems, are introduced. It is proved that for both classes, the block-Krylov subspaces induced by the matrices in these classes can be viewed as multiple copies of certain subspaces of the state space of the original higher-order system.
A Thin Film Nitinol Heart Valve

In order to create a less thrombogenic heart valve with improved longevity, a prosthetic heart valve was developed using thin film nitinol (NiTi). A "butterfly" valve was constructed using a single, elliptical piece of thin film NiTi and a scaffold made from Teflon tubing and NiTi wire. Flow tests and pressure readings across the valve were performed in vitro in a pulsatile flow loop. Bio-corrosion experiments were conducted on untreated and passivated thin film nitinol. To determine the material's in vivo biocompatibility, thin film nitinol was implanted in pigs using stents covered with thin film NiTi. Flow rates and pressure tracings across the valve were comparable to those through a commercially available 19 mm Perimount Edwards tissue valve. No signs of corrosion were present on thin film nitinol samples after immersion in Hank's solution for one month. Finally, organ and tissue samples explanted from four pigs at 2, 3, 4, and 6 weeks after thin film NiTi implantation appeared without disease, and the thin film nitinol itself was without thrombus formation. Although long term testing is still necessary, thin film NiTi may be very well suited for use in artificial heart valves.
Infinite class towers for function fields

This paper gives examples of function fields K0 over a finite field Fq of p power order ramified only at one finite regular prime over Fq(t), which admit infinite Hilbert p-class field towers. Such a K0 can be taken as an extension of a cyclotomic function field Fq(t)(λpm) for a certain regular prime p in Fq[t].
Patient perceptions of service quality: combining the dimensions

Empirically investigates, using a conjoint methodology, the importance weights given the attributes of quality for acute care hospital services. The study shows consumers evaluated the technical dimensions of nursing care, physician care, and outcome as more important than the accommodation functions of hospital care, and there are significant interactions among the technical dimensions. Both sets of dimensions were important and significant, but technical quality evaluations were not influenced by the perceived quality level of the affective attributes. The relative importance of these attributes were quite stable among various subgroups of past patients.
The Heavy-element Composition of Disk Instability Planets Can Range from Sub- to Super-nebular

Transit surveys combined with Doppler data have revealed a class of gas giant planets that are massive and highly enriched in heavy-elements (e.g., HD 149026b, GJ436b, and HAT-P-20b). It is tempting to consider these planets as validation of core accretion plus gas capture because it is often assumed that disk instability planets should be of nebular composition. We show in this paper, to the contrary, that gas giants that form by disk instability can have a variety of heavy-element compositions, ranging from sub- to super-nebular values. High levels of enrichment can be achieved through one or multiple mechanisms, including enrichment at birth, planetesimal capture, and differentiation plus tidal stripping. As a result, the metallicity of an individual gas giant cannot be used to discriminate between gas giant formation modes.
I see you're talking #HPV: communication patterns in the #HPV stream on Twitter

This poster reports data from a pilot study of communication practices in the microblogging site Twitter. A content analysis was conducted on a random sample of 50 tweets from the #hpv (human papillomavirus) stream in order to determine any recurring practices such as use of links, retweets, uses of the @ symbol, and other phenomena. The pilot study found that, unlike studies conducted on communication patterns in Twitter streams, the participants in the #hpv stream use it to primarily broadcast information as opposed to interacting and conversing with one another, and collaboration, while present indirectly, is minimal. The researcher plans to expand the sample set to 900 tweets and continue the process of content analysis in order to determine more solid findings for practices of communication in this space. The researcher also plans to examine other spaces relevant to the exchange of information on HPV, conduct content analyses for them, and compare them to the findings on Twitter. The goal is to use these findings for both health and technical communication so that better systems can be designed to optimize the power of participant generated information spaces.
Existence of an optimal growth path with endogenous technical change

Abstract We prove the existence of an optimal growth path in an economy where goods that are not consumed are either invested in next period capital or in R&D with overall non-convex production possibilities, using results of non-linear functional analysis in weighted Lp spaces of Chichilnisky (Journal of Optimization Theory and Applications, 1977, 61, no. 2, 504–520) and (Journal of Mathematical Economics, 1981, 8, 1–14).
Maximal invariants for Lorentz-Wishart models

Abstract In this paper we consider two statistical hypotheses for the families of Wishart type distributions. These distributions are analogs of the Wishart distributions defined and parametrized over a Lorentz cone. We test these hypotheses by means of maximal invariant statistics which are explicitly derived in the paper. The testing problems, respectively, concern the hypothesis that parameters are in a sub-Lorentz-cone and the hypothesis that two observations have the same parameter.
The sovereign ceiling and emerging market corporate bond spreads

Abstract We use the spreads of emerging market bonds traded in secondary markets to study investors' perception of country risk. Specifically, we ask whether investors apply the “sovereign ceiling,” which says that no firm is more creditworthy than its government. To do this we compare the spreads of bonds issued by firms to those of bonds issued by the firms' home governments. We find several cases where a firm's bond trades at a lower spread than that of the firm's government, indicating that investors do not always apply the sovereign ceiling. Bonds for which this is true tend to have substantial export earnings and/or a close relationship with either a foreign firm or with the home government.
Influence of Substrate Temperature on Physical Structure of AlN Thin Films Prepared on Polycrystalline MoSi2 by rf Magnetron Sputtering

c-axis-oriented aluminum nitride thin films were prepared on polycrystalline molybdenum disilicide substrates by rf magnetron sputtering at substrate temperatures of 50°–500°C. The films with the best orientation and crystallinity were prepared at 300°C. The dependence of film microstructure on substrate temperature was investigated by atomic force microscopy (AFM). Consequently, the microstructure changed in accordance with the model proposed by Thornton. It was found that the orientation and crystallinity of the films were optimal when the films consisted of dense fibrous grains. Further, it was confirmed that piezoelectric measurements could be made from the films during mechanical impacts.
A Rapid and Convenient Synthesis of Homoallylic Alcohols by the Barbier‐Grignard Reaction

Abstract The use of the Barbier‐Grignard reaction, where premixed allyl bromide and the carbonyl compound are added to magnesium in ether, is reported for the synthesis of homoallylic alcohols. This reaction provides good to excellent yields of most homoallylic alcohols with minimal formation of Wurtz coupling products.
Quantum Hall Effect: Current distribution and the role of measurement

Based on very general arguments we show that for any geometry of the experiment, in the regime when the measurement leads to a quantized Hall conductivity, almost the entire current injected into the sample is carried by the bulk states. The crucial role of the contacts equilibrating different edge channels is emphasized.
Paleozoic paleogeography of North America, Gondwana, and intervening displaced terranes: Comparisons of paleomagnetism with paleoclimatology and biogeographical patterns

New paleomagnetic data have become available in the past 5 yr that require modifications in previously published paleogeographic reconstructions for the Silurian and Devonian. In this paper, the new paleopoles are compared to published paleogeographic models based on paleoclimatologic and biogeographic data. The data from the three fields of paleomagnetism, paleoclimatology, and biogeography are generally in excellent agreement, and an internally consistent paleogeographic evolutionary picture of the interactions between North America, Gondwana, and intervening displaced terranes is emerging.During the interval of the Ordovician, Silurian, and Devonian, North America stayed in equatorial paleoposition, while rotating counter-clockwise. The northwest African part of Gondwana was in high southerly latitudes during the Late Ordovician and was fringed by peri-Gondwanide terranes, such as southern Europe (Armorica) and Avalonian basement blocks now found in eastern Newfoundland, Nova Scotia, the Boston Basin, the Appalachian Piedmont, and northern Florida. Subsequently, Gondwana and the peri-Gondwanide terranes displayed rapid drift with respect to the pole. This drift translates into the following pattern of movement for northwest Africa. During the latest Ordovician-Early Silurian, this area moved rapidly northward from polar to subtropical latitudes, followed by equally rapid southward motion from subtropical to intermediate (about 50°S) paleolatitudes during the Late Silurian-Middle Devonian. It is likely that significant east-to-west motion accompanied the latter shift in paleolatitudes, with the Caledonian-Acadian orogeny the result of Silurian to Early Devonian convergence and collision between Gondwana and North America. This collision sandwiched several of the intervening displaced terranes between Gondwana and North America. Subsequent to this collision, Gondwana was separated in the Late Devonian by a medium-width ocean from North America and the Avalonian and southern European blocks which were left behind adjacent to North America. This new ocean closed during the Carboniferous, and the resulting convergence and collision were the cause of the Hercynian-Alleghanian orogenic belt. Problems remaining for future research, besides the further gathering of reliable paleopoles, involve the uncertain pre-Devonian position of the southern British Isles in this scenario and the very rapid velocity with respect to the pole that results from the rapid Late Ordovician-Silurian apparent polar wander for Gondwana.
Left behind to farm ? women's labor re-allocation in rural China

The transformation of work during Chinas rapid economic development is associated with a substantial but little noticed re-allocation of traditional farm labor among women, with some doing much less and some much more. This paper studies how the work, time allocation, and health of non-migrant women are affected by the out-migration of others in their household. The analysis finds that the women left behind are doing more farm work than would have otherwise been the case. There is also evidence that this is a persistent effect, and not just temporary re-allocation. For some types of women (notably older women), the labor re-allocation response comes out of their leisure.
Crystal structure of SmAsS

Abstract The crystal structure of SmAsS was determined from a single crystal grown using a LiCl/RbCl salt flux. Two parallel refinements in both the monoclinic space group of P21/c and the orthorhombic space group of Pnma were performed. It was determined that SmAsS crystallized in the orthorhombic space group of Pnma with the lattice parameters of a=3.8544(2) A, b=3.9063(2) A and c=17.1134(11) A.
Filming seismograms and related materials at the California Institute of Technology

As part of a world-wide effort to create an international earthquake data bank, Caltech's seismology archive has been organized, labeled, described, and microfilmed. It includes a wide variety of original records, documents, and printed materials relating to local and distant earthquakes. At present, we are filming significant seismograms prior to 1963; more than 50,000 records written between 1924 and 1935 have been filmed to date. Seismograms are the principal source of information about earthquakes and the earth's interior. These records, housed at Kresge Laboratory, the headquarters for Caltech's seismological network of stations, are important because they span so much of the period for which instrumental data exists. The early history of the Laboratory points up the role technology has played in the advancement of the science.
On the long run effect of public capital on aggregate output: Estimation and sensitivity analysis

We undertake a sensitivity analysis of the productivity of public capital under the aggregate production function approach. Several proxies are used for the private inputs and for public capital, several dummy variables are included to adjust for energy price shocks, newly revised data is studied, and Stock and Watson’s dynamic OLS estimator is used. Our main results are that the productivity of public capital depends critically on the proxies used, the effects are typically smaller than the early estimates, and omitting the oil price shocks introduces significant upward bias in the measured productivity of public capital.
Synthesis of triazole-oxazolidinones via a one-pot reaction and evaluation of their antimicrobial activity.

Abstract C-5-substituted triazole-oxazolidinones were synthesized using a bromide catalyzed cycloaddition between aryl isocyanates and epibromohydrin followed by a three-component Huisgen cycloaddition. The library of compounds was screened for antibacterial activity against Mycobacterium smegmatis ATCC 14468, Bacillus subtilis ATCC 6633, and Enterococcus faecalis ATCC 29212. Notably, the 3-(4-acetyl-phenyl)-5-(1 H -1,2,3-triazol-1-yl)methyl)-oxazolidin-2-one ( 18 ) showed an MIC of 1 μg/mL against M. smegmatis ATCC 14468, fourfold lower than the MIC measured for isoniazid.
Idea of a new anatomy of the thalamus.

Review of some of the advances in knowledge about the thalamus and various aspects of thalamic function and organization accomplished during the last 15 years with the aid of improved neurophysiological research methods. Special attention is given to cytoarchitectural differentiations which, heretofore of little more than descriptive interest, have gradually begun to be clarified in terms of their functional significance.
Gold(I)-catalyzed enantioselective intramolecular hydroamination of allenes.

The asymmetric intramolecular hydroamination of allenes catalyzed by phosphinegold(I)−bis-p-nitrobenzoate complexes is described. This reaction is applicable to the enantioselective formation of vinyl pyrrolidines and piperidines in 70−99% ee.
Ending Tyranny in Iraq

The war in Iraq has reignited the passionate humanitarian intervention debate. President George W. Bush surprised many observers in his second inaugural address when he promised to oppose tyranny and oppression, and this in a world not always willing or ready to join in that fight. Humanitarian intervention is again on the forefront of world politics.
The contribution of nonhomothetic preferences to trade

Abstract This paper estimates the economic significance of preference nonhomotheticity in international trade. Tastes are assumed to be identical, but budget shares depend on per capita income. A linear expenditure system is estimated for 34 countries over 11 commodity aggregates. A counterfactual exercise is conducted to estimate the volume of trade caused by deviations from homotheticity. The results indicate that nonhomothetic preferences may account for as much as one-quarter of interindustry trade flows.
Group II metabotropic glutamate receptor type 2 allosteric potentiators prevent sodium lactate-induced panic-like response in panic-vulnerable rats:

Rats with chronic inhibition of GABA synthesis by infusion of l-allyglycine, a glutamic acid decarboxylase inhibitor, into their dorsomedial/perifornical hypothalamus are anxious and exhibit panic-like cardio-respiratory responses to treatment with intravenous (i.v.) sodium lactate (NaLac) infusions, in a manner similar to what occurs in patients with panic disorder. We previously showed that either NMDA receptor antagonists or metabotropic glutamate receptor type 2/3 receptor agonists can block such a NaLac response, suggesting that a glutamate mechanism is contributing to this panic-like state. Using this animal model of panic, we tested the efficacy of CBiPES and THIIC, which are selective group II metabotropic glutamate type 2 receptor allosteric potentiators (at 10-30 mg/kg i.p.), in preventing NaLac-induced panic-like behavioral and cardiovascular responses. The positive control was alprazolam (3mg/kg i.p.), a clinically effective anti-panic benzodiazepine. As predicted, panic-prone rats given a NaLac challenge displayed NaLac-induced panic-like cardiovascular (i.e. tachycardia and hypertensive) responses and "anxiety" (i.e. decreased social interaction time) and "flight" (i.e. increased locomotion) -associated behaviors; however, systemic injection of the panic-prone rats with CBiPES, THIIC or alprazolam prior to the NaLac dose blocked all NaLac-induced panic-like behaviors and cardiovascular responses. These data suggested that in a rat animal model, selective group II metabotropic glutamate type 2 receptor allosteric potentiators show an anti-panic efficacy similar to alprazolam.
Reverse the Diastereoselectivity of the Rh(I)-Catalyzed Pauson-Khand Cycloaddition

It is discovered that the diastereoselectivity of the Rh(I)-catalyzed Pauson–Khand cycloaddition of chiral enynes can be reversed to generate the trans diastereomer as the major product in the absence of a chelate phosphine ligand when the substrate contains an appropriate functional group capable of chelate coordination to the Rh(I) center. This expands the application of the Rh(I)-based catalytic processes to prepare both the cis and trans stereoisomers.
A White Dwarf Merger Paradigm for Supernovae and Gamma-Ray Bursts

Gamma-ray bursts can appear to be a hundred times as luminous as supernovae, but their underlying energy source(s) have remained a mystery. However, there has been evidence for some time now of an association of gamma-ray bursts with supernovae of Type Ib and Ic, a fact which has been exploited by a number of models, to explain the gamma-ray burst phenomenon. Here we interpret the results of basic observations of SN 1987A and of pulsars in globular clusters, to propose the energy source, which powers at least some long-duration gamma-ray bursts, as core-collapse following the merger of two white dwarfs, either as stars or stellar cores. The beaming and intrinsic differences among gamma-ray bursts arise, at least in part, from differing amounts and composition of the gas in the merged stellar common envelopes, with the more energetic bursts resulting from mergers within less massive envelopes. In order for the beams/jets associated with gamma-ray bursts to form in mergers within massive common envelopes (as with SN 1987A), much of the intervening stellar material in the polar directions must be cleared out by the time of core-collapse, or the beams/jets themselves must clear their own path. The core-collapse produces supernovae of Type Ib, Ic, or II (as with SN 1987A, a SNa IIp), leaving a weakly magnetized neutron star remnant with a spin period near 2 milliseconds. There is no compelling reason to invoke any other model to account for gamma-ray bursts. Far from being an unusual event, SN 1987A is typical, having the same merger source of initiation as 95% of all supernovae, the rare exceptions being Ia's induced via gradual accretion from a binary companion, and Fe catastrophe II's.
TRANSIT OBSERVATIONS OF THE WASP-10 SYSTEM

We present here observations of the transit of WASP-10b on 2009 October 14 UT taken from the University of Arizona's 1.55 m Kuiper telescope on Mount Bigelow. Conditions were photometric and accuracies of 2.0 mmag rms were obtained throughout the transit. We have found that the ratio of the planet to host star radii is in agreement with the measurements of Christian et al. instead of the refinements of Johnson et al., suggesting that WASP-10b is indeed inflated beyond what is expected from theoretical modeling. We find no evidence for large (>20 s) transit timing variations in WASP-10b's orbit from the ephemeris of Christian et al. and Johnson et al.
ALGORITHMICALLY FINITE GROUPS

We call a group G algorithmically finite if no algorithm can produce an infinite set of pairwise distinct elements of G. We construct examples of recursively presented infinite algorithmically finite groups and study their properties. For instance, we show that the Equality Problem is decidable in our groups only on strongly (exponentially) negligible sets of inputs.
Polyketide construction via hydrohydroxyalkylation and related alcohol C–H functionalizations: reinventing the chemistry of carbonyl addition

Covering: up to the end of 2013 Despite the longstanding importance of polyketide natural products in human medicine, nearly all commercial polyketide-based drugs are prepared through fermentation or semi-synthesis. The paucity of manufacturing routes involving de novo chemical synthesis reflects the inability of current methods to concisely address the preparation of these complex structures. Direct alcohol C–H bond functionalization via “C–C bond forming transfer hydrogenation” provides a powerful, new means of constructing type I polyketides that bypasses stoichiometric use of chiral auxiliaries, premetallated C-nucleophiles, and discrete alcohol-to-aldehyde redox reactions. Using this emergent technology, total syntheses of 6-deoxyerythronolide B, bryostatin 7, trienomycins A and F, cyanolide A, roxaticin, and formal syntheses of rifamycin S and scytophycin C, were accomplished. These syntheses represent the most concise routes reported to any member of the respective natural product families.
Adaptive Interference Alignment with CSI Uncertainty

Interference alignment (IA) is known to significantly increase sum-throughput at high SNR in the presence of multiple interfering nodes, however, the reliability of IA is little known, which is the subject of this paper. We study the error performance of IA and compare it with conventional orthogonal transmission schemes. Since most IA algorithms require extensive channel state information (CSI), we also investigate the impact of CSI imperfection (uncertainty) on the error performance. Our results show that under identical rates, IA attains a better error performance than the orthogonal scheme for practical signal to noise ratio (SNR) values but is more sensitive to CSI uncertainty. We design bit loading algorithms that significantly improve error performance of the existing IA schemes. Furthermore, we propose an adaptive transmission scheme that not only considerably reduces error probability, but also produces robustness to CSI uncertainty.
Maltreated and nonmaltreated children's evaluations of emotional fantasy

IntroductionA range of developmental consequences can result following children’s exposure to maltreatment (see Cicchetti & Toth,2003). Typically, consequences reﬂect delays in cognitive development and poor mental health functioning (e.g., Myers etal., 2002). However, maltreated children sometimes demonstrate superior performance relative to nonmaltreated childrenwhenengagedinemotion-relevanttasks(e.g.,PollakT Samuels & Taylor, 1994). Atleast two explanations for children’s responses have been proposed. First, responses may reﬂect children’s desires for onlycertain events to occur (Carrick & Quas, 2006; Woolley, 1997). That is, children ﬁnd the positive events appealing and wantthem to occur, but perceive the negative events as potentially threatening and consequentially do not want them to occur.
Techniques for the Management of Frequency Bands Shared Between Terrestrial Stations and Mobile or Transportable Earth Stations

The allocation of frequency bands on a shared basis to different radiocommunications services has created requirements for specialized spectrum management techniques. Techniques used in the management of frequency bands shared between terrestrial stations and mobile or transportable Earth stations are presented.
Natural products, small molecules, and genetics in tuberculosis drug development.

The impact of natural products on the well being of mankind has been enormous, and their study continues to influence research in the fields of chemistry, biology, and ecology. Historically, the majority of our medicines originate from natural products and their synthetic derivatives, many of which have taught us valuable lessons about biology. While advances in synthetic and combinatorial chemistry have given rise to notable successes in the development of new drugs, the perceived value of natural products has not waned when it comes to treating infectious diseases. In this Miniperspective, we review the role natural products have played in the treatment of tuberculosis (TBa), their value and limitations as chemical probes, the challenges associated with TB drug development, and the current status of natural product and synthetic small molecules as new TB drug leads.
DETECTION OF OH ABSORPTION AGAINST PSR B1718-35

OH absorption against PSR B1718–35 at (l,b) = 351.688°, +0.671° has been discovered at 1665 and 1667 MHz using the Green Bank Telescope. The absorption appears to arise at the interface of an H II region and a molecular cloud that are likely associated with the high-mass star-forming region NGC 6334. Beam dilution is found to be the cause of differences between the opacity of the OH against the Galactic background continuum emission and against the pulsar. The OH cloud is approximately 3 × 1.3 pc and is located behind the H II region.
Research on supersonic combustion

Introduction S OME qualifications to the pretentious nature of the title of this Paper are in order. Research in this context is applied, i.e., it is directed toward the design and development of devices. The devices are air breathing propulsion systems, wherein supersonic combustion is inherent or it provides an adjunct benefit. Principal applications of the former are manned hypersonic aircraft, transatmospheric accelerators, and missiles. Typical examples of the latter are external burning systems that sustain thrust or reduce drag when used in tandem with primary accelerator engines. This Paper is not at all representative of the complete body of the research on supersonic combustion. Instead, what is presented is primarily based on material with which the writer has had either direct involvement or a first-hand knowledge. It does not do justice to the exemplary works of many other investigators. Hopefully, this is somewhat rectified by the extensive list of references. The reader is encouraged to consult these manuscripts to obtain a more balanced perspective. This applied research must be viewed from the perspective of the engineer who is charged with expediting development and is in the need of design tools. Exact physics have frequently been abandoned to produce functional models. Much of the experimental verification upon which the models are based has been obtained in facilities which have known imperfections with respect to duplication of flight conditions. Moreover, compromises have been made in the analysis and interpretation of the experimental data, in part due to imperfect or incomplete diagnostic instrumentation, and in part due to a limited understanding of the underlying physics. An example that embodies all of these deficiencies would be a design model that is based on the use of integral techniques to describe combustion in supersonic flow from experiments conducted in an arc-heated tunnel.
Enantioselective Organocatalytic Singly Occupied Molecular Orbital Activation: The Enantioselective α-Enolation of Aldehydes

The first enantioselective organocatalytic α-enolation of aldehydes has been accomplished using singly occupied molecular orbital (SOMO) catalysis. Chiral secondary amines react with aldehydes to form transient enamines that undergo selective one-electron oxidation to generate electrophilic radical cations. These SOMO-activated radical cations are susceptible to attack by ketone-derived enol silanes, rendering α-substituted-γ-ketoaldehyde products with uniformly high levels of asymmetric induction. Wide latitude in both the aldehyde and enolsilane component is readily accommodated, allowing generic access to a diverse assortment of enantioenriched 1,4-dicarbonyl compounds. This report highlights the potential of SOMO catalysis to enable the development of entirely new classes of asymmetric reactions that have no traditional catalytic equivalents.
Warped product Einstein metrics over spaces with constant scalar curvature

In this paper we study warped product Einstein metrics over spaces with constant scalar curvature. We call such a manifold rigid if the universal cover of the base is Einstein or is isometric to a product of Einstein manifolds. When the base is three dimensional and the dimension of the fiber is greater than one we show that the space is always rigid. We also exhibit examples of solvable four dimensional Lie groups that can be used as the base space of non-rigid warped product Einstein metrics showing that the result is not true in dimension greater than three. We also give some further natural curvature conditions that characterize the rigid examples in higher dimensions.
Observed electric fields associated with lightning initiation

[1] In situ electric field (E) measurements and inferred lightning initiation locations of three cloud-to-ground flashes are used to identify a thunderstorm region in which the preflash E exceeded the threshold for runaway breakdown. The maximum measured E in the region was 186 kV m−1 at 5.77 km altitude, which for runaway electrons is equivalent to 370 kV m−1 at sea level; this E value is ∼130% of the estimated threshold for an avalanche of runaway electrons. In addition, the volume where E exceeded the runaway threshold was estimated to be 1–4 km3, with a vertical depth of about 1000 m. At least within part of this volume the characteristic scale height for exponential growth of runaway electrons was 100 m or less. Thus for these three flashes the electric field conditions necessary for runaway breakdown existed, and runaway breakdown could have initiated the flashes.
Integrated Teaching of Experimental and Communication Skills to Undergraduate Aerospace Engineering Students

The joint teaching of an undergraduate Experimental Projects Lab and a Communications Practicum is discussed. Written and oral assignments developed, shaped, and peer reviewed as part of the communications practicum, are used to satisfy the written and oral requirements for the experimental projects subject. The joint structure serves to educate students in a variety of aspects of professional practice including solving open-ended problems, system-level integration of disciplinary coursework, project development and planning, oral and written communication, peer review, and teamwork. The paper describes the unique features of this educational strategy, and represents a progress report following a three-year experimental implementation of the new course format. Assessment of the effectiveness of the courses is presented based on student evaluations and comments from the instructors. A high level of satisfaction with this new model is expressed, suggesting that both the quality of the research performed and the students' ability to transmit an understanding of that research to others have been enhanced.
Generation and cycloaddition reactions of transient alkyl-substituted anhydro-4-hydroxythiazolium hydroxides

Abstract Transient alkyl-substituted anhydro-4-hydroxythiazolium hydroxides undergo efficient inter- and intramolecular cycloaddition to provide the corresponding 1,3-dipolar cycloadducts in high yield.
Duality of the Fermionic 2d Black Hole and N = 2 Liouville Theory as Mirror Symmetry

We prove the equivalence of the SL(2, R)/U(1) Kazama-Suzuki model, which is a fermionic generalization of the 2d Black Hole, and N = 2 Liouville theory. We show that this duality is an example of mirror symmetry. The essential part of the derivation is to realize the fermionic 2d Black Hole as the low energy limit of a gauged linear sigma-model. Liouville theory is obtained by dualizing the charged scalar fields and taking into account the vortex-instanton effects, as proposed recently in non-dilatonic models. The gauged linear sigma-model we study has many useful generalizations which we briefly discuss. In particular, we show how to construct a variety of dilatonic superstring backgrounds which generalize the fermionic 2d Black Hole and admit a mirror description in terms of Toda-like theories.
Asymptotically truthful equilibrium selection in large congestion games

Studying games in the complete information model makes them analytically tractable. However, large n player interactions are more realistically modeled as games of incomplete information, where players may know little to nothing about the types of other players. Unfortunately, games in incomplete information settings lose many of the nice properties of complete information games: the quality of equilibria can become worse, the equilibria lose their ex-post properties, and coordinating on an equilibrium becomes even more difficult. Because of these problems, we would like to study games of incomplete information, but still implement equilibria of the complete information game induced by the (unknown) realized player types. This problem was recently studied by Kearns et al [Kearns et al. 2014], and solved in large games by means of introducing a weak mediator: their mediator took as input reported types of players, and output suggested actions which formed a correlated equilibrium of the underlying game. Players had the option to play independently of the mediator, or ignore its suggestions, but crucially, if they decided to opt-in to the mediator, they did not have the power to lie about their type. In this paper, we rectify this deficiency in the setting of large congestion games. We give, in a sense, the weakest possible mediator: it cannot enforce participation, verify types, or enforce its suggestions. Moreover, our mediator implements a Nash equilibrium of the complete information game. We show that it is an (asymptotic) ex-post equilibrium of the incomplete information game for all players to use the mediator honestly, and that when they do so, they end up playing an approximate Nash equilibrium of the induced complete information game. In particular, truthful use of the mediator is a Bayes-Nash equilibrium in any Bayesian game for any prior.
On the X-Ray-heated Skin of Accretion Disks

We present a simple analytical formula for the Thomson depth of the X-ray-heated skin of accretion disks valid at any radius and for a broad range of spectral indices of the incident X-rays, accretion rates, and black hole masses. We expect that this formula may find useful applications in studies of geometry of the inner part of accretion flows around compact objects, and in several other astrophysically important problems, such as the recently observed X-ray "Baldwin" effect (i.e., monotonic decrease of the Fe line's equivalent width with the X-ray luminosity of active galactic nuclei [AGNs]), the problem of the missing Lyman edge in AGNs, and line and continuum variability studies in accretion disks around compact objects. We compute the reflected X-ray spectra for several representative cases and show that for hard X-ray spectra and large ionizing fluxes the skin represents a perfect mirror that does not produce any Fe lines or absorption features. At the same time, for soft X-ray spectra or small ionizing fluxes, the skin produces a very strong ionized absorption edge and highly ionized Fe lines that should be observable in the reflected spectra.
Development of an icosahedral quasicrystal and two approximants in the Ca-Au-Sn system: syntheses and structural analyses.

The realm of Tsai-type (YCd6-type) quasicrystals (QCs) and their approximants (ACs) continues to expand to the east in the periodic table. The heavy tetrel Sn is now one of the major components in the new Ca15.0(5)Au60.0(4)Sn25.0(2) (atom %) icosahedral QC and in the corresponding 1/1 and 2/1 ACs. (The 2/1 AC with Yb is also established.) Single-crystal X-ray diffraction on a 1/1 AC gives the refined formula of Ca3Au14.36(3)Sn4.38(5) in space group Im3, a = 15.131(1) A, whereas a representative 2/1 AC gives Ca13Au47.2(1)Sn28.1(1), Pa3 and a = 24.444(1) A. Both ACs contain five-shell multiply endohedral triacontahedral clusters as the common building blocks, as in the parent structure of YCd6. The 2/1 AC also contains four Ca2-dimer-centered prolate rhombohedra (PRs) in the unit cell. The long-range order between triacontahedra and PRs in the 2/1 AC is the same as those in Bergman-type 2/1 ACs. A TB-LMTO-ASA calculation on an ideal 1/1 AC model reveals a shallow pseudogap in the total densities-of-states...
J/ψ Production from Charm Coalescence in Relativistic Heavy Ion Collisions

J/ψ production is closely related to the production of the strongly interacting Quark-Gluon Plasma (sQGP) in relativistic heavy ion collisions. To study the effects of charm quark dynamics on J/ψ production, the phase space distributions of charm and anti-charm quarks are generated using A Multi-Phase Transport (AMPT) model. These charm quarks then coalesce into J/ψ particles. The production and flow of J/ψ show strong sensitivity to final state charm interactions. The results are compared to charm quark and D meson results from the AMPT model and recent predictions from other models.
Laser material characteristics of Ti:Al 2 O 3

Quasi-cw operation of Ti:sapphire crystals pumped by a chopped cw argon-ion laser was used to determine gain and loss coefficients of this material. A considerable variation in the material loss coefficients was observed as a function of the coordinates of the pumped volume in the laser crystal, indicating crystal inhomogeneity.
Computing without processors

The duopoly of computing has up until now been delimited by drawing a line in the sand that defines the instruction set architecture as the hard division between software and hardware. On one side of this contract Intel improved the design of processors and on the other side of this line Microsoft developed ever more sophisticated software. This cozy relationship is now over as the distinction between hardware and software is blurred due to relentless pressure for performance and reduction in latency and energy consumption. Increasingly we will be forced to compute with architectures and machines which do not resemble regular processors with a fixed memory hierarchy based on heuristic caching schemes. Other ways to bake all that sand will include the evolution of GPUs and FPGAs to form heterogeneous computing resources which are much better suited to meeting our computing needs than racks of multicore processors. This presentation will highlight some of the programming challenges we face when trying to develop for heterogeneous architectures and a few promising lines of attack are identified.
Intrinsically Disordered Titin PEVK as a Molecular Velcro: Salt-Bridge Dynamics and Elasticity

It is increasingly recognized that many proteins are intrinsically disordered and do not have a unique compact structure as those found in globular proteins. Titin is a giant modular protein (3-4 MDa) found in the muscle sarcomere that is comprised of both globular and disordered modules. The elastic titin PEVK segment, with tandem repeats of ∼28 residue modules, plays a major role in the passive tension of skeletal and heart tissues. We have proposed based on AFM studies of a cloned titin PEVK fragment, that salt-bridges play a central role in the elasticity of this PEVK polyelectrolyte. We have engineered a construct of 15 repeats of a single titin 28-residue PEVK module (human exon 172). The 50 kDa polyprotein shows well-resolved NMR spectra in dilute solution and in highly concentrated gels. Both chemical shifts and sequential NOE's indicate the presence of polyproline II helices. From long-range NOE's, we observed, for the first time, stable K to E salt-bridges with non-random pairings. Simulated annealing with NMR restraints yielded a manifold of plausible structures for an exon 172 trimer showing many salt-bridges. Steered molecular dynamics simulations (SMD) were done to study how the manifold of salt-bridges evolves during the stretching experiment. Repeated SMD simulations at slow velocity (0.0005 nm/ps) show force spectra consistent with experimental AFM force spectra of the polyprotein. SMD shows that salt-bridges occur even at high degrees of stretch and that these short range interactions are in integral part of the mechanical properties of PEVK. We propose that the long-range, non-stereospecific nature of electrostatic interactions provide a facile mechanism to tether and untether the flexible chains, which in turn affect elasticity as well as control the accessibility of protein-protein interaction to these nanogel-like proteins.
Field-aligned distribution of the plasmaspheric electron density: An empirical model derived from the IMAGE RPI measurements

[1] We present a newly developed empirical model of the plasma density in the plasmasphere. It is based on more than 700 density profiles along field lines derived from active sounding measurements made by the radio plasma imager on IMAGE between June 2000 and July 2005. The measurements cover all magnetic local times and vary from L = 1.6 to L = 4 spatially, with every case manually confirmed to be within the plasmasphere by studying the corresponding dynamic spectrogram. The resulting model depends not only on L-shell but also on magnetic latitude and can be applied to specify the electron densities in the plasmasphere between 2000 km altitude and the plasmapause (the plasmapause location itself is not included in this model). It consists of two parts: the equatorial density, which falls off exponentially as a function of L-shell; and the field-aligned dependence on magnetic latitude and L-shell (in the form of invariant magnetic latitude). The fluctuations of density appear to be greater than what could be explained by a possible dependence on magnetic local time or season, and the dependence on geomagnetic activity is weak and cannot be discerned. The solar cycle effect is not included because the database covers only a fraction of a solar cycle. The performance of the model is evaluated by comparison to four previously developed plasmaspheric models and is further tested against the in situ passive IMAGE RPI measurements of the upper hybrid resonance frequency. While the equatorial densities of different models are mostly within the statistical uncertainties (especially at distances greater than L = 3), the clear latitudinal dependence of the RPI model presents an improvement over previous models. The model shows that the field-aligned density distribution can be treated neither as constant nor as a simple diffusive equilibrium distribution profile. This electron density model combined with an assumed model of the ion composition can be used to estimate the time for an Alfven wave to propagate from one hemisphere to the other, to determine the plasma frequencies along a field line, and to calculate the raypaths for high frequency waves propagating in the plasmasphere.