cssi/SciSciGPT-SciSciNet huggingface dataset:
The synthesis and binding properties of nano-scale hydrophobic pockets

Computational investigations into the conformational preferences of previously reported host 4 are presented. Single point calculations, in conjunction with NMR evidence, indicate that the open conformation is considerably more stable than the closed form. The thermodynamic binding parameters for nano-scale host 4 encapsulating a range of halogenated guests are reported. Association constants for guests as small as bromobenzene, to as large as 3[(1R)-endo]-(+)-bromocamphor, were determined in both deuterated chloroform and toluene-d8. The unavailability of large guests prevented determining the optimal guest to cavity volume ratio for this rigid host. In contrast however examining a range of small guests indicated that in the less competitive toluene, binding only occurred with guests that filled greater than 33% of the cavity. As anticipated all halogenated guests were noted to bind halogen atom down, indicating that the formation of C–H⋯X–R hydrogen bonds is a major contributor to complex stability. Three related hosts with more open cavities were synthesized to evaluate the effects of preorganization of the cavity walls on guest binding. Binding studies with the best guest for 4, 1-iodoadamantane, demonstrated that cavity wall integrity and rigidity is essential for strong binding. These results are set in context of how de Novo active-site syntheses may provide access to new catalysts with tailored properties and/or substrate selectivities. Important considerations relating to this task, and possible ways in which the field may develop in accomplishing this goal, are also briefly discussed.
A Soft X-Ray Transient in the M31 Bulge

We have examined a probable soft X-ray transient source in the M31 bulge at R.A. = 0h42m41814 ± 008, decl. = 41°16'3586 ± 007. On the three occasions we observed the source, its spectrum was soft (kTin ≈ 1 keV). The brightest detection of the source was on 2004 July 17, with a 0.3-7 keV luminosity of ~5 × 1037 ergs s-1. The only previous detection of the source was in 1979 by the Einstein observatory. The multiple detections over 25 years suggest that the duty cycle of the source is in the range 0.02-0.06. Coordinated HST ACS imaging before, during, and after the outburst revealed no variable optical source within the position errors of the X-ray source. The optical data place a firm upper limit on the brightness of the counterpart of the X-ray outburst of B > 24.7, suggesting that the binary has a period 5.2 days. The X-ray spectrum and lack of bright stars at the source location indicate that the source was a soft transient event occurring in a low-mass X-ray binary, making this source a good black hole candidate in M31.
Mercury in the air, water and biota at the Great Salt Lake (Utah, USA).

Abstract The Great Salt Lake, Utah (USA), is the fourth largest terminal lake on Earth and a stop-over location for 35 million birds on the Pacific Flyway. Recently, the Utah Department of Health and Utah Division of Wildlife Resources issued tissue mercury (Hg) consumption advisories for several species of birds that consume the lake's brine shrimp. We hypothesized that the chemistry of the atmosphere above the Great Salt Lake would facilitate atmospheric deposition of Hg to the water. Because little information was available on Hg at the Great Salt Lake, and to begin to test this hypothesis, we measured atmospheric elemental (Hg 0 ) and reactive gaseous mercury (RGM) concentrations as well as Hg concentrations in water and brine shrimp five times over a ~year. Surrogate surfaces and a dry deposition model were applied to estimate the amount of Hg that could be input to the lake surface, and HYSPLIT model back trajectories were developed to investigate potential sources of RGM to the lake. Atmospheric Hg 0 concentrations were similar to global ambient background values and RGM concentrations were similar to those reported for rural areas. Both Hg 0 and RGM exhibited regular diel variability. Model estimated deposition velocities for RGM to the lake ranged from 0.9 to 3.0 cm s − 1 while that determined for surrogate surfaces ranged from 2.8 to 7.8 cm s − 1 . Filtered total and methyl Hg concentrations in Great Salt Lake surface waters were consistent throughout the year (3.6 ± 0.8 ng L − 1 and 0.93 ± 0.59 ng L − 1 , respectively), while brine shrimp concentrations had a statistically significant increase from summer to fall. Data collected and data analyses indicated no direct local or regional source of Hg to the lake and that factors within the Great Salt Lake basin are important in controlling Hg 0 and RGM concentrations.
All loop N = 2 string amplitudes

Using the N = 4 topological reformulation of N = 2 strings, we compute all loop partition function for special compactifications of N = 2 strings as a function of target moduli. We also reinterpret N = 4 topological amplitudes in terms of slightly modified N = 2 topological amplitudes. We present some preliminary evidence for the conjecture that N = 2 strings is the large N limit of Holomorphic Yang-Mills in four dimensions.
Clusters, Currents, and Whitehead's Algorithm

Using geodesic currents, we provide a theoretical justification for some of the experimental results obtained by Haralick, Miasnikov, andMyasnikov via pattern-recognition methods regarding the behavior of Whitehead's algorithm on nonminimal inputs. In particular, we prove that the images of "random" elements of a free group F under the automorphisms of F form "clusters" that share similar normalized Whitehead graphs and similar behavior with respect to Whitehead's algorithm.
Dynamics of liquid sloshing in upright and inverted bladdered tanks

A system identification methodology was used to examine the dynamics of liquid sloshing in the upright and inverted bladdered hydrazine tanks of the Tracking and Data Relay Satellite, (TDRS) and to evaluate the effects of bladder stiffness on the sloshing parameters. Mechanical models of the two systems were developed using the numerical values derived from static stability tests and from slosh frequency response tests of a full-size model tank fitted with a prototype bladder. For the upright tank (liquid below the bladder) a modified conventional pendulum was used. In the inverted tank (liquid above the bladder) where sloshing is unconventional due to the highly nonsymmetrical orientation of the liquid held by the bladder, a mechanical model using an inverted pendulum which is able to undergo small oscillations as well as large reorientations was necessary. Both thrusting and low-gravity conditions are considered.
Finite element developments for two dimensional multiple-interface phase change problems

Finite element developments for multiple phase change problems in two-dimensional models are presented for the first time. The enthalpy method is used to simulate latent heat release in conjunction with fixed grid techniques. An unconditionally stable implicit method is used for the time integration. The effects of boundary conditions and the different phase regions on the multiple phase front developments are examined for numerous examples. Discussions and conclusions are appropriately addressed.
Neutralino Proton Cross Sections in SUGRA and D-BRANE Models

We calculate the spin independent neutralino-proton cross section for universal SUGRA, non universal SUGRA and D-brane models with R-parity invariance. The regions of maximum cross section in these models has started to be probed by the current detectors. The minimum cross section generally is and hence will be accessible in the future detectors, barring special regions of parameter space where it can reduce to ≃10-12pb. However, the squarks and gluinos will be heavy in the latter case, but still accessible at the LHC.
Main-Sequence Mass Loss and the Lithium Dip

The significant dip in observed lithium abundances for Population I stars near M about 1.3 solar mass is discussed. It is noted that this dip occurs near where the instability strip crosses the main sequence on the lower edge of the Delta Scuti stars and that stellar pulsations are expected to give rise to mass loss. A total mass loss of 0.05 solar mass over the main-sequence lifetime of these stars would be sufficient to explain the observations of lithium depletion. The absence of a dip in the Pleiades and of significant depletion of beryllium in the Hyades places tight constraints on the rate of mass loss. These constraints make unlikely the high main-sequence mass-loss rates which would significantly affect globular cluster ages.
Asymmetric synthesis of the Japanese beetle pheromone via boronic esters

Abstract The pheromone of the Japanese beetle, [ R -( Z )]-5-(1-decenyl)dihydro-2(3 H )-furanone ( 7 ), has been synthesized efficiently in high enantiomeric purity via 1,2-dicyclohexyl-1,2-ethanediol boronic esters. The synthetic route involves reaction of an α-chloro boronic ester with an alkynyllithium, and provides the first successful example of this substitution process in an asymmetric synthesis.
Phosphate anion binding by macrocyclic dinucleating ligands and their metal complexes

Abstract Four closely related dinuclear macrocyclic ligands are described: 1,13-dioxa-4,7,10,16,19,11-hexaazacyclotetracosane (OBISDIEN), 3,6,9,17,20,23-hexaazatricyclo[23.3.1.1 11,15 ]triconta-(1(29),11(30),12,14,25,27-hexaaza (BMXD), 3,6,9,16,19,22-hexaaza-27-28-dioxatricyclo-[22.2.1.1 11,14 ]-octacos-1,(26),11,13,24-tetraene (BFBD), and 3,6,9,17,20,23,29,30-octaazatri-cyclo[23.3.1.1 11,15 ]triconta-1(29),11,13,15,25,27-hexaene (BPBD). These macrocycles may be considered hexaaza ligands with two diethylenetriamine moieties bound together by bridging groups, except for BPBD, for which the bridging groups are pyridine rings, making this an octaaza ligand; however the remaining six nitrogens are analogous to those in OBISDIEN, BFBD, and BMXD. The syntheses of these ligands are outlined and compared. Each ligand forms six protonated species, which bind anions through hydrogen bonding and coulombic forces, the strength of binding increases with the number of protons, corresponding to an increase in the number of hydrogen bonds and to an increase in the coulombic attractive forces. The binding of these macrocyclic ligands to the nucleotides ATP, ADP, and AMP and their inorganic analogs, triphosphate, pyrophosphate, and phosphate, are described in detail, with equilibrium constants given for each species formed. The selectivities of the macrocyclic ligands for the nucleotides are described. With the aid of species distribution curves in competitive systems, the use of macrocycles for the separation of ATP, ADP, and AMP is suggested. It is shown that these aza macrocycles form both mono- and dinuclear metal complexes. The stabilities of the mononuclear ternary Cu(II) complexes are increased by hydrogen bonds between the coordinated phosphate and the protonated amino groups, with a maximum attained with three hydrogen bonds. For dinuclear ternary complexes protonation and deprotonation reduce the stability since the former reduces the number of amino donors coordinating the Cu(II), while the latter increases the number of hydroxide ions coordinated directly with the metal ion. The dinuclear Cu(II) complex shows a preference for the binding of ATP over ADP, especially in moderately alkaline solution.
Dark Halo Shapes and the Fate of Stellar Bars

We investigate the stability properties of trajectories in barred galaxies with mildly triaxial halos by means of Liapunov exponents. This method is perfectly suitable for time-dependent three-dimensional potentials where surfaces of sections and other simple diagnostics are not applicable. We find that when halos are centrally concentrated most trajectories starting near the plane containing the bar become chaotic. The spatial density distribution of these orbits does not match that of the bar, being overextended in and out of the plane compared to the latter. Moreover, the shape of many of the remaining regular trajectories does not match the bar density distribution, being too round. Therefore, time-independent self-consistent solutions are highly unlikely to be found. When the nonrotating nonaxisymmetric perturbation in the potential reaches 10%, almost all trajectories integrated are chaotic and have large Liapunov exponents. No regular trajectories aligned with the bar have been found. Hence, if the evolution of the density figure is directly related to the characteristic timescale of orbital instability, bar dissolution would take place on a timescale of a few dynamical times. The slowly rotating nonaxisymmetric contribution to the potential required for the onset of widespread chaotic behavior is remarkably small. Even a potential axis ratio of 0.99 results in large connected chaotic regions dominating the space of initial conditions. Systems consisting of centrally concentrated axisymmetric halos and stellar bars thus appear to be structurally unstable, and small (~1%) deviations from perfect axisymmetry should result in a bar dissolution on a timescale significantly smaller than the Hubble time. Since halos found in cold dark matter simulations of large-scale structure are both centrally concentrated and triaxial, it is unlikely that stellar bars embedded in such halos would form and survive unless the halos are modified during the formation of the baryonic component.
Does the Minimum Wage Affect Welfare Caseloads

Although minimum wages are advocated as a policy that will help the poor, few studies have examined their effect on poor families. This paper uses variation in minimum wages across states and over time to estimate the impact of minimum wage legislation on AFDC caseloads, thus directly assessing whether minimum wages benefit a group they are intended to help. We find that the elasticity of the welfare caseload with respect to the minimum wage is 0.20. This suggests that minimum wages are not an efficient policy for facilitating the transition from welfare to work. We appreciate the financial support of the Joint Center for Poverty Research and the U.S. Department of Agriculture. We would also like to thank Mark Smith for providing us with the political variables, Aaron Yelowitz for supplying us with the Medicaid data, and Matthew Harrington for helping us collect and analyze other state-level data. We also thank Michael Baker, David Ellwood, Oscar Jorda, Peggy O’BrienStrain, Anne Piehl, Robert Plotnick, Deborah Reed, Kim Rueben, Mark Smith, James Ziliak and participants in the Bay Area Labor Economists workshop, the UC-Davis Applied Microeconomics seminar, the NBER Universities Research Conference and the Public Policy Institute of California brown bag series, for their suggestions. Tracy Turner provided outstanding research assistance.
Equilibrium air radiation from shock layers at 11.3 km/sec.

High resolution equilibrium radiation spectra for shock layer of blunt bodies at reentry velocities and radiative recombination of N and O ions
The 2-leg Hubbard ladder: computational studies of new materials

Computational studies of basic models of strongly correlated electron systems can provide guidance in the search for new materials as well as insight into the physical mechanisms responsible for their properties. Here, we illustrate this by examining what numerical computations have shown us about the 2-leg Hubbard ladder.
An alcohol recognition motif: Clear evidence of binding site cooperativity in the complexation of cyclohexanediols by neutral polyaza-clefts

Abstract A polyaza-cleft is found to bind a variety of alcohol functional groups via two hydrogen bonds. The tethering of two clefts yields cooperativity between binding sites.
A new copper-catalyzed [3 + 2] cycloaddition: enantioselective coupling of terminal alkynes with azomethine imines to generate five-membered nitrogen heterocycles.

A copper-catalyzed method for the regioselective 1,3-dipolar cycloaddition of azomethine imines to terminal alkynes has been developed. Through the use of a chiral phosphaferrocene−oxazoline ligand, a wide range of substrates can be coupled to generate useful heterocycles in very good enantiomeric excess.
The determinants of sexual freedom from 1990 to 2010

With sexual freedom represented by the changing definition of marriage in the news lately, the question this article seeks to answer is what drives the issue of sexual freedom. This article focuses on the hypothesized link between sexual freedom and possible explanatory factors. Data are obtained from 1990 to 2010. The examination of data shows that median income, ideology, median age, population density and religion variables are significant in understanding sexual freedom in the United States.
Photon excitation for satellite-free X-ray spectroscopy: Instrumentation challenges

Abstract Soft X-ray emission spectra (SXES) obtained using monochromatic synchrotron radiation (SR) provides important advantages as compared with electron excitation. Photons can penetrate deep into the sample providing nondestructive information from bulk samples. With availability of tunable monochromatic photons from synchrotron sources, it is now possible to selectively ionize core electrons near enough to the core level threshold energy producing singly ionized atoms and molecules resulting in satellite-free X-ray emission spectra. This offers the ability to separate satellite structure from diagram lines and also allows more detailed studies of the satellite processes. Recent developments in satellite-free SXES will be reviewed along with instrumentation challenges in utilizing the small phase-space attributes of high brightness from third-generation SR sources producing soft X-ray and vacuum ultraviolet wavelengths.
Evaluating the Practical Low-Speed Limits for Back-EMF Tracking-Based Sensorless Speed Control Using Drive Stiffness as a Key Metric

Although it is widely known that back-electromotive-force tracking has a low-speed limit, there is very little published literature evaluating this limit. This paper shows that the low-speed limit is mainly a function of the amplitude of the inverter harmonics and that theory and simulation will provide erroneous results when inverter harmonics are not incorporated. This paper will also provide a method for evaluating this low-speed limit using drive stiffness as the metric. The experimental results show quantitatively how the drive stiffness suffers as speed decreases, which ultimately sets the practical low-speed limit.
Nitrations of 4',5'-dihydropsoralens: a route to radiopharmaceutical precursors

Unlike the nitration of the fully-aromatic furocoumarin, methoxsalen, which yields a single nitration product, the nitration of the 4′,5′-dihydro compound generates a condition-variant mixture of three nitro products. Reduction, diazotization, and pyrrolidine-trapping of one of these, the 4′,5′-dihydro-5-nitro-8- methoxypsoralen, provides a pyrrolidine triazene precursor for radioiodination of the dihydropsoralen system.
Of Attitudes and Engagement: Clarifying the Reciprocal Relationship Between Civic Attitudes and Political Participation

In this essay, we draw on broader psychological theories of the attitude–behavior relationship to postulate specific reciprocal patterns of causality between the civic attitudes and forms of political and civic engagement featured in contemporary political communication research. We then examine the extent of these reciprocal relationships with a 2-wave panel survey of 2,872 Pacific Northwest residents. Spanning the 2004 elections, structural equation modeling of the panel data shows complex reciprocal causal paths between political/civic attitudes (internal and external efficacy and civic pride and faith) and a range of political and civic behaviors (voting, political action, media use, political/community talk, and group involvement). The conclusion suggests how to conceptualize these variables and model their relationships in future research.
Access to Justice for Persons with Disabilities: An Emerging Strategy

Persons with disabilities often find themselves marginalized by society and by our justice systems. We can improve access to justice by training better advocates. Advocates not only must be knowledgeable concerning relevant laws and regulations, but also must be able to interact effectively on a personal, professional level with persons who have disabilities. We also want to make certain that persons with disabilities have the opportunity to learn to advocate for themselves and for other persons with disabilities. Technologies are available that can help us accomplish these goals. This article provides a brief survey of legal protections (and gaps in such protection) for persons with disabilities. Successful advocate training programs from around the world are identified and described. The article provides examples of how technology is being used to support these efforts and provides suggestions regarding additional ways in which technology could be employed. Law schools around the world have begun to embrace the goal of better advocacy, but improving access will require well-prepared advocates to answer the call. Training advocates to provide services to a population that may have significantly different needs even within that population may be a more efficient and effective way to improve access to justice than by attempting to draft laws and regulations that somehow address all possible circumstances.
Z-Sum approach to loop integrals using Taylor expansion

We study the applicability of the Z-Sum approach to multi-loop calculations with massive particles in perturbative quantum field theory. We systematically analyze the case of one-loop scalar integrals, which represent the building blocks of any higher-loop calculation. We focus in particular on triangle one-loop integrals and identify strengths and limitations of the Z-Sum approach, extending our results to the case of one-loop box integrals when appropriate. We conclude with the calculation of a specific physical example: the calculation of heavy-flavor corrections to deep-inelastic-scattering structure functions.
Combining results of different models : the case of a levy on the Dutch nitrogen surplus

Economic instruments, such as levies are considered by the Dutch government for reducing the harmful effects of the production and application of manure. To analyse these levies a framework which makes it possible to combine and to choose among different types of research is developed. The results are integrated along the line of the marginal abatement cost curve. The problems related to integrating different types of research are taken into account. The method developed allows every farmer to react to a levy differently. A levy turns out to be more effective to reduce the nitrogen surplus on farm level in the pig fattening sector when compared to the pig breeding sector. But even a levy of 2 guilders/kg of nitrogen does not remove the total manure surplus in the pig sector and results in large profit losses. Further research is needed to underpin the empirical input required by the model.
SYNTHESIS OF LIPOPHILIC 3-HYDROXY-2-METHYL-4-PYRIDINONE DERIVATIVES

Abstract Hydrophilic 2- hydroxy-3-methyl-4-pyridinone derivatives were acylated with either long chain acid chlorides or with 1,3,5-benzenetricarbonyl trichloride. The products are either partially lipophilic, bidentatate or hexadentate chelators that form strong 3:1 and 1:1 complexes, respectively, with Fe (III).
SYNTHESIS OF L-INDOSPICINE

ABSTRACT Preparation of L-indospicine in eight steps by a reaction sequence starting with L-lysine.
An air-stable palladium/N-heterocyclic carbene complex and its reactivity in aryl amination.

The synthesis and characterization of [Pd(IPr)Cl2]2 (1), an air- and moisture-stable complex, is reported. The utilization of 1 as a catalyst for amination of aryl chlorides and bromides with a variety of amine coupling partners under mild conditions is described. The amination reactions with 1 show a remarkable insensitivity to oxygen and water, and thus the amination reactions could be performed in air on the benchtop with undried reagent grade solvents and substrates with small effects on reaction times and conversions.
Chemical Nonequilibrium Boundary Layer

The nonequilibrium boundary layer is considered as a binary mixture of atoms and molecules with finite dates of dissociation and recombination. To obtain accurate solutions to the partial differential equations for this type of flow without any necessary simplifying assumptions, an implicit finite-difference scheme is developed for solving these equations with a digital computer. Accurate solutions to the nonequilibrium boundary-layer equations have been obtained in a reasonable amount of computer time and are presented for a flat plate, cone, and hemisphere cylinder. The results show that the nonequilibrium boundary-layer temperature and composition can be considerably different from local equilibrium and frozen results. For a cone at 21,000 fps and 100,000 ft alt, the computations show that, at 60 ft from the tip, the flow has not reached equilibrium.
Regular combinators for string transformations

We focus on (partial) functions that map input strings to a monoid such as the set of integers with addition and the set of output strings with concatenation. The notion of regularity for such functions has been defined using two-way finite-state transducers, (one-way) cost register automata, and MSO-definable graph transformations. In this paper, we give an algebraic and machine-independent characterization of this class analogous to the definition of regular languages by regular expressions. When the monoid is commutative, we prove that every regular function can be constructed from constant functions using the combinators of choice, split sum, and iterated sum, that are analogs of union, concatenation, and Kleene-*, respectively, but enforce unique (or unambiguous) parsing. Our main result is for the general case of non-commutative monoids, which is of particular interest for capturing regular string-to-string transformations for document processing. We prove that the following additional combinators suffice for constructing all regular functions: (1) the left-additive versions of split sum and iterated sum, which allow transformations such as string reversal; (2) sum of functions, which allows transformations such as copying of strings; and (3) function composition, or alternatively, a new concept of chained sum, which allows output values from adjacent blocks to mix.
Node removal vulnerability of the largest component of a network

The connectivity structure of a network can be very sensitive to removal of certain nodes in the network. In this paper, we study the sensitivity of the largest component size to node removals. We prove that minimizing the largest component size is equivalent to solving a matrix one-norm minimization problem whose column vectors are orthogonal and sparse and they form a basis of the null space of the associated graph Laplacian matrix. A greedy node removal algorithm is then proposed based on the matrix one-norm minimization. In comparison with other node centralities such as node degree and betweenness, experimental results on US power grid dataset validate the effectiveness of the proposed approach in terms of reduction of the largest component size with relatively few node removals.
Generalized Abbe Principle: Position Error Propagation in Machine Elements

In the quest for ever finer levels of technology integration, mechanical linkages reach their precision limits at about 5 micrometers per meter of workspace. Beyond this physical limit, all six dimensional degrees offreedom need to be precisely ascertained to account for mechanical imperfections. This paper substantiates Wu's vision of precision machines without precision machinery. A formulation and statistical characterization of position and orientation error propagation in rigid bodies are presented for two extreme models of measurement. It is shown that error distribution is uniquely dependent upon the design of the measurement plan. The theoretical foundations presented were evolved in the course of designing precision machinery. Other potential applications include: fixture design, metrology, and geometric tolerance verification.
Dietary fiber and cancer

There is considerable current interest in the role of dietary fiber in the etiology of a number of diseases prevalent in the Western world. Prominent among those disease states whose prevalence is correlated with diets deficient in fiber is cancer of the large bowel. The high level of interest in the fiber hypothesis is due, in large part, to the epidemiologic observations of Burkitt and his colleagues1–3 who perceived that one factor common among diseases of the large bowel was a diet low in fiber. Drasar and Irving,4 on the other hand, correlated incidence of breast and colon cancer with a number of environmental factors and found a high positive correlation with total fat and animal protein, but practically none with dietary fiber (Table 15-1).
Multiple-Input, Multiple-Output Time-Series Models from Short Data Records

An algorithm to estimate multiple-input, multiple-output, time-series models for structural system identification using short time histories is presented. The method uses order overspecification to reduce estimation bias and automatically sorts identified system modes from computational modes. The system natural frequencies, damping factors, mode shapes, and modal participation factors are estimated and can be used to reconstruct singleinput, single-output models for every input-output pair. Experimental data from a large cantilevered flexible truss are used to demonstrate the technique. Modal estimates are comparable to those obtained using accepted methods such as the eigensystem realization algorithm.
Presence, segregation and reactivity of H, C and N dissolved in some refractory oxides

The sources of impurities, particularly carbon, in high melting oxides and silicates are discussed, along with detection and quantification methods. The impurities are important for their effects on bulk material properties through the media of, e.g., surface or grain boundary characteristics. The impurities are usually encountered by the contact of the oxide (refractory) material with volatiles such as H2O and CO2, which become incorporated in the material and form anion complexes with oxygen acting as a covalent bonded ligand. The specific processes undergone by MgO in assimilating C impurities are delineated, using data obtained with X-ray photoelectron spectroscopy, Auger electron spectroscopy, secondary ion mass spectrometry and nuclear reaction profiling. Finally, maintenance of a supersaturated solid solution with C impurities by space charge control is described as a means of offset impurity effects.
Chromosome- and spindle-pole-derived signals generate an intrinsic code for spindle position and orientation

Mitotic spindle positioning by cortical pulling forces defines the cell division axis and location, which is critical for proper cell division and development. Although recent work has identified developmental and extrinsic cues that regulate spindle orientation, the contribution of intrinsic signals to spindle positioning and orientation remains unclear. Here, we demonstrate that cortical force generation in human cells is controlled by distinct spindle-pole- and chromosome-derived signals that regulate cytoplasmic dynein localization. First, dynein exhibits a dynamic asymmetric cortical localization that is negatively regulated by spindle-pole proximity, resulting in spindle oscillations to centre the spindle within the cell. We find that this signal comprises the spindle-pole-localized polo-like kinase (Plk1), which regulates dynein localization by controlling the interaction between dynein-dynactin and its upstream cortical targeting factors NuMA and LGN. Second, a chromosome-derived RanGTP gradient restricts the localization of NuMA-LGN to the lateral cell cortex to define and maintain the spindle orientation axis. RanGTP acts in part through the nuclear localization sequence of NuMA to locally alter the ability of NuMA-LGN to associate with the cell cortex in the vicinity of chromosomes. We propose that these chromosome- and spindle-pole-derived gradients generate an intrinsic code to control spindle position and orientation.
Spatial structure of spectral transport in two-dimensional flow

Using filter-space techniques (FSTs), we study the spatial structure of the scale-to-scale flux of energy in two-dimensional flow. Analysing data from a weakly turbulent, experimental quasi-two-dimensional flow, we find rotationally symmetric patterns consisting of lobes of spectral flux of alternating sign that are associated with vortical motion in the flow field. Such patterns also occur in a simple analytical model, even though the single-scale model flow should have no scale-to-scale energy transfer. Thus, the interpretation of these alternating patterns must be handled with care. By decomposing the spectral flux into three distinct components, we show that these lobe patterns are entirely associated with the Leonard and, to a lesser extent, cross terms. In addition, we show that the contributions from these two terms are localized around the energy injection scale, and that the bulk of the inverse energy transfer in our flow is carried by the subgrid term alone.
State estimation with probability constraints

This paper considers a state estimation problem for a discrete-time linear system driven by a Gaussian random process. The second order statistics of the input process and state initial condition are uncertain. However, the probability that the state and input satisfy linear constraints during the estimation interval is known. A minimax estimation problem is formulated to determine an estimator that minimises the worst-case mean square error criterion, over the uncertain second order statistics, subject to the probability constraints. It is shown that a solution to this constrained state estimation problem is given by a Kalman filter for appropriately chosen input and initial condition models. These models are obtained from a finite dimensional convex optimisation problem. The application of this estimator to an aircraft tracking problem quantifies the improvement in estimation accuracy obtained from the inclusion of probability constraints in the minimax formulation.
Vortex configurations in the large N limit

Abstract We study the properties of vortex-like configurations which are solutions of the SU( N ) Yang-Mills classical equations of motion. We show that these solutions are concentrated along a two-dimensional wall with size growing with the number of colors.
The organization and management of the Virtual Astronomical Observatory

The U.S. Virtual Astronomical Observatory (VAO http://www.us-vao.org/) has been in operation since May 2010. Its goal is to enable new science through efficient integration of distributed multi-wavelength data. This paper describes the management and organization of the VAO, and emphasizes the techniques used to ensure efficiency in a distributed organization. Management methods include using an annual program plan as the basis for establishing contracts with member organizations, regular communication, and monitoring of processes.
Unquenched studies using the truncated determinant algorithm

A truncated determinant algorithm is used to study the physical effects of the quark eigenmodes associated with eigenvalues below 420 MeV. This initial high statistics study focuses on coarse (6{sup 4}) lattices (with O(a{sup 2}) improved gauge action), light internal quark masses and large physical volumes. Three features of full QCD are examined: topological charge distributions, string breaking as observed in the static energy and the eta prime mass.
The ERO Host Galaxy of GRB 020127: Implications for the Metallicity of GRB Progenitors

We present optical and near-IR observations of the host galaxy of GRB 020127, for which we measure R - K_s = 6.2 mag. This is only the second GRB host to date classified as an ERO. The spectral energy distribution (SED) is typical of a dusty starburst galaxy, with a redshift z ≈ 1.9, a luminosity L ≈ 5L^*, and an inferred stellar mass of M_* ~ 10^(11)-10^(12) M_⊙, two orders of magnitude more massive than typical GRB hosts. A comparison to the z ~ 2 mass-metallicity (M-Z) relation suggests that the host metallicity is about 0.5-1Z_⊙. This result shows that at least some GRBs occur in massive, metal-enriched galaxies, and that the proposed low-metallicity bias of GRB progenitors is not as severe as previously claimed. Instead, we propose that the blue colors and sub-L^* luminosities of most GRB hosts reflect their young starburst populations. This explanation also accounts for the prevalence of low-redshift GRBs in low-mass galaxies, since star formation activity shifts from high- to low-mass galaxies as a function of decreasing redshift ("downsizing"). Thus, the low-metallicity bias claimed for z ≾ 0.2 GRB hosts is likely a secondary effect, which reflects the M-Z relation, and consequently GRBs and their hosts may serve as a reliable tracer of cosmic star formation activity.
String theory in magnetic monopole backgrounds

Abstract We discuss string propagation in the near-horizon geometry generated by Neveu-Schwarz fivebranes, Kaluza-Klein monopoles and fundamental strings. When the fivebranes and KK monopoles are wrapped around a compact four-manifold M , the geometry is AdS 3 × S 3 / Z N × M and the space-time dynamics is expected to correspond to a local two-dimensional conformal field theory. We determine the moduli space of space-time CFT's, study the spectrum of the theory and compare the chiral primary operators obtained in string theory to supergravity expectations.
a Constraint on the Anomalous GREEN’S Function

It is shown that the physical constraint of the Anomalous Green’s function gives a natural pairing condition. The resulting self-consistency equation is directly related to the BCS gap equation. Both inhomogeneous and homogeneous systems are considered to illustrate the importance of the constraint. Especially we find weak localization correction to the phonon-mediated interaction.
Linking Diversity and Stable Isotope Fractionation in Ammonia-Oxidizing Bacteria

The link between similarity in amino acid sequence for ammonia monooxygenase (AMO) and isotopic discrimination for ammonia oxidation ( l AMO ) was investigated in g -subdivision ammonia-oxidizing bacteria. The isotope effects for ammonia oxidation in pure cultures of the nitrifying strains Nitrosomonas marina , Nitrosomonas C-113a, Nitrosospira tenuis , Nitrosomonas europaea , and Nitrosomonas eutropha ranged from 14.2 to 38.2. The differences in isotope effects could not be readily explained by differential rates of ammonia oxidation, transport of NH 4 + , or accumulation of NH 2 OH or N 2 O among the strains. The major similarities and differences observed in l AMO are, however, paralleled by similarities and differences in amino acid sequences for the f -subunit of AMO (AmoA). Robust differences in l AMO among nitrifying bacteria may be expected to influence the stable isotopic signatures of nitrous oxide (N 2 O) produced in various environments.
Some new transformations for Bailey pairs and WP-Bailey pairs

We derive several new transformations relating WP-Bailey pairs. We also consider the corresponding transformations relating standard Bailey pairs, and as a consequence, derive some quite general expansions for products of theta functions which can also be expressed as certain types of Lambert series.
SPACE-BASED TESTS OF GRAVITY WITH LASER RANGING

Existing capabilities of laser ranging, optical interferometry, and metrology, in combination with precision frequency standards, atom-based quantum sensors, and drag-free technologies, are critical for space-based tests of fundamental physics; as a result of the recent progress in these disciplines, the entire area is poised for major advances. Thus, accurate ranging to the Moon and Mars will provide significant improvements in several gravity tests, namely the equivalence principle, geodetic precession, PPN parameters β and γ, and possible variation of the gravitational constant G. Other tests will become possible with the development of an optical architecture that allows one to proceed from meter to centimeter to millimeter range accuracies on interplanetary distances. Motivated by anticipated accuracy gains, we discuss the recent renaissance in lunar laser ranging and consider future relativistic gravity experiments with precision laser ranging over interplanetary distances.
Cross-Coupling Reactions of Alkenylsilanols with Fluoroalkylsulfonates: Development and Optimization of a Mild and Stereospecific Coupling Process.

The development of an effective protocol for the palladium-catalyzed cross-coupling of (E)- and (Z)-alkenylsilanols with aryl triflates is described. A critical component in the optimization of this method was balancing the stability and reactivity of the triflates in the presence of a nucleophilic promoter. This report highlights that the use of a slightly soluble Bronsted base promoter that allows for a low, steady-state concentration of alkenyl(dimethyl)silanolate in solution, thus facilitating cross-coupling in preference to S-O bond cleavage of the triflate.
RELATIVISTIC MANY-BODY CALCULATIONS

Inner electrons in atoms and ions of high nuclear charge, Z, move with velocities comparable to the velocity of light.
Unitarity of compactified five-dimensional Yang–Mills theory

Abstract Compactified five-dimensional Yang–Mills theory results in an effective four-dimensional theory with a Kaluza–Klein (KK) tower of massive vector bosons. We explicitly demonstrate that the scattering of the massive vector bosons is unitary at tree-level for low energies, and analyze the relationship between the unitarity violation scale in the KK theory and the nonrenormalizability scale in the five-dimensional gauge theory. In the compactified theory, low-energy unitarity is ensured through an interlacing cancellation among contributions from the relevant KK levels. Such cancellations can be understood using a Kaluza–Klein equivalence theorem which results from the geometric “Higgs” mechanism of compactification. In these theories, the unitarity violation is delayed to energy scales higher than the customary limit through the introduction of additional vector bosons rather than Higgs scalars.
Flight Simulation of a Vehicle with a Two-Stage Parachute System

A QUICK response, 9-DOF (degree-of-freedom) hybrid computer code has been developed to simulate the flight of an aircraft-delivered, parachute-retarded vehicle. The mathematical model and its implementation are discussed. The particular case of a vehicle with a first-stage lifting parachute and second-stage descent parachute is investigated. Results compare well with those obtained from an existing 12DOF digital code and from full-scale flight test.
Computation of the optimal normal load of a friction damper under different types of excitation

In this paper, forced responses of a frictionally damped turbine blade are investigated for three different types of excitation: white noise excitation, narrowband random excitation, and deterministic sinusoidal excitation. To determine the steady-state nonlinear response, the harmonic balance method is used for sinusoidal excitation, and the equivalent linearization method is used for white noise and narrowband random excitations. Using a new set of nondimensionalized variables, the optimal value of normal load of a friction damper is found to be almost independent of the nature of excitation. The effectiveness of the damper in reducing the vibration level is also examined for the aforementioned three different types of excitation.
On a communitarian approach to bioethics

A communitarian approach to bioethics adds a core value to a field that is often more concerned with considerations of individual autonomy. Some interpretations of liberalism put the needs of the patient over those of the community; authoritarian communitarianism privileges the needs of society over those of the patient. Responsive communitarianism’s main starting point is that we face two conflicting core values, autonomy and the common good, and that neither should be a priori privileged, and that we have principles and procedures that can be used to work out this conflict but not to eliminate it. This discussion uses the debate in the US over funding for entitlements as a case study to apply the values of communitarian bioethics.
Mass and Cost Model for Selecting Thruster Size in Electric Propulsion Systems

A model of system mass and life-cycle costs is used to determine the optimal number of thrusters for electric propulsion systems. The model is generalized for application with most electric propulsion systems and then applied to high-power Hall thruster systems in particular. Mass and cost models were constructed for individual thruster strings using as inputs the number of active thrusters, the number of redundant thrusters, and the total system power. Mass and cost are related through the launch cost of the propulsion-system mass, which unifies the optimization to a single global parameter based on cost. Fault-tolerance and string cost are driving factors determining the optimum thruster size for a given system-power level. After considering factors such as fault-tolerance, cost uncertainty, complexity, ground-test-vacuum-facility limitations, previously demonstrated power capabilities, and possible technology limitations, the development of two thrusters to flight status is suggested: a low-power model...
Wake Vortex Alleviation Flow Field Studies

Wake-vortex-allevialion research was conducted in the far-field vortex wake of a generic wing-tail aircraft model. The goats were to achieve accelerated vortex strength reduction and to map the conditions at which this reduction would occur. The wing-tail model was run in a water tow tank to generate a pair of unequal-strength counterrotating vortices on each side of centerline. Dye flow visualization provided physical insight into the nature of the vortex interactions, and three-component particle image velocimetry allowed quantification of key characteristics of the flowfield, including circulation, vorticity, vortex trajectory, and induced rolling moments. Experiments were conducted for a variety of model angles of attack, tail incidence angles, and tail spans
Exact feature probabilities in images with occlusion

To understand the computations of our visual system, it is important to understand also the natural environment it evolved to interpret. Unfortunately, existing models of the visual environment are either unrealistic or too complex for mathematical description. Here we describe a naturalistic image model and present a mathematical solution for the statistical relationships between the image features and model variables. The world described by this model is composed of independent, opaque, textured objects, which occlude each other. This simple structure allows us to calculate the joint probability distribution of image values sampled at multiple arbitrarily located points, without approximation. This result can be converted into probabilistic relationships between observable image features as well as between the unobservable properties that caused these features, including object boundaries and relative depth. We show that the image model is sufficient to explain a wide range of natural scene properties. Finally, we discuss the implications of this description of natural scenes for the study of vision.
Stereoselective Negishi-like Couplings Between Alkenyl and Alkyl Halides in Water at Room Temperature

Mix in water and then stir. That is all that is required in this new approach to stereoselective sp(3)-sp(2) cross-couplings between an alkyl and alkenyl halide. Prior formation of organozinc reagents is not required.