cssi/SciSciGPT-SciSciNet huggingface dataset:
A Method for Determining the Star Formation History of a Mixed Stellar Population

We present a method to determine the star formation history of a mixed stellar population from its photometry. We perform a χ2 minimization between the observed photometric distribution and a model photometric distribution, based on theoretical isochrones. The initial mass function, distance modulus, interstellar reddening, binary fraction, and photometric errors are incorporated into the model, making it directly comparable to the data. The model is a linear combination of individual synthetic color-magnitude diagrams (CMDs), each of which represents the predicted photometric distribution of a stellar population of a given age and metallicity. While the method is similar to existing synthetic CMD algorithms, we describe several key improvements in our implementation. In particular, we focus on the derivation of accurate error estimates on the star formation history to enable comparisons between such histories, either from different objects or from different regions of a single object. We present extensive tests of the algorithm, using both simulated and actual photometric data. From a preliminary application of the algorithm to a subregion of the Large Magellanic Cloud (LMC), we find that the that the lull in star formation observed among the LMC's cluster population between 3 and 8 Gyr ago is also present in the field population. The method was designed with flexibility and generality in mind, and we make the code available for use by the astronomical community.
Efficient aqueous-phase Heck and Suzuki couplings of aryl bromides using tri(4,6-dimethyl-3- sulfonatophenyl)phosphine trisodium salt (TXPTS).

Sterically demanding, sulfonated arylphosphines TXPTS and TMAPTS have been applied to the aqueous-phase Heck and Suzuki coupling of aryl bromides. TXPTS provides good yields of Heck coupling products from aryl bromides at 80 °C, while both TMAPTS and TPPTS gave significantly less active catalysts. TXPTS is the first ligand to promote the aqueous-phase Heck coupling under such mild conditions. Both TXPTS and TMAPTS provide active catalysts for Suzuki couplings of aryl bromides at 50 °C.
The First Ultra-cool Brown Dwarf Discovered by the Wide-field Infrared Survey Explorer

We report the discovery of the first new ultra-cool brown dwarf (BDs) found with the Wide-field Infrared Survey Explorer (WISE). The object's preliminary designation is WISEPC J045853.90+643451.9. Follow-up spectroscopy with the LUCIFER instrument on the Large Binocular Telescope indicates that it is a very late-type T dwarf with a spectral type approximately equal to T9. Fits to an IRTF/SpeX 0.8-2.5 μm spectrum to the model atmospheres of Marley and Saumon indicate an effective temperature of approximately 600 K as well as the presence of vertical mixing in its atmosphere. The new BD is easily detected by WISE, with a signal-to-noise ratio of ~36 at 4.6 μm. Current estimates place it at a distance of 6-10 pc. This object represents the first in what will likely be hundreds of nearby BDs found by WISE that will be suitable for follow-up observations, including those with the James Webb Space Telescope. One of the two primary scientific goals of the WISE mission is to find the coolest, closest stars to our Sun; the discovery of this new BD proves that WISE is capable of fulfilling this objective.
Electrostatic interactions across a charged lipid bilayer.

We present theoretical work in which the degree of electrostatic coupling across a charged lipid bilayer in aqueous solution is analyzed on the basis of nonlinear Poisson–Boltzmann theory. In particular, we consider the electrostatic interaction of a single, large macroion with the two apposed leaflets of an oppositely charged lipid bilayer where the macroion is allowed to optimize its distance to the membrane. Three regimes are identified: a weak and a high macroion charge regime, separated by a regime of close macroion–membrane contact for intermediate charge densities. The corresponding free energies are used to estimate the degree of electrostatic coupling in a lamellar cationic lipid–DNA complex. That is, we calculate to what extent the one-dimensional DNA arrays in a sandwich-like lipoplex interact across the cationic membranes. We find that, in spite of the low dielectric constant inside a lipid membranes, there can be a significant electrostatic contribution to the experimentally observed cross-bilayer orientational ordering of the DNA arrays. Our approximate analytical model is complemented and supported by numerical calculations of the electrostatic potentials and free energies of the lamellar lipoplex geometry. To this end, we solve the nonlinear Poisson–Boltzmann equation within a unit cell of the lamellar lipoplex using a new lattice Boltzmann method.
Seasons and depression: the influence of cigarette smoking.

The seasonality of depressive illness has been documented since antiquity. A review of 611 patients, who were consecutively admitted to the adult inpatient psychiatric unit of a mid-Michigan general hospital, examined the influence of cigarette smoking and psychiatric diagnosis upon the seasonal variation of admissions. Among the smokers, admissions for depressive disorders (n = 151) peaked in the springtime (z = 2.1, p < .05) and declined in summer. Admissions for the nonsmokers failed to demonstrate a substantial seasonal rhythm. Admissions for smokers and nonsmokers in other diagnostic groups did not show any seasonal variation. These findings parallel numerous studies regarding the influence of seasons upon rates of hospitalization for depressive disorder, and completed suicide. Therapeutic implications related to the bidirectional relationship between cigarette smoking and depression are discussed.
Decision support systems in dentistry.

Decision-support systems hold a specialized body of knowledge in computerized form such that the non- specialist can obtain expert-level information. The goal of these systems in clinical sciences is usually to assist patient care by providing the clinician with improved diagnosis or treatment planning. Decision-support systems consist of three components: the user interface through which the clinician or patient enters signs or symptoms, the set of data describing clinical knowledge in the domain of the program, and an inference engine to manipulate the data set in light of a patient's specific signs or symptoms to arrive at a diagnosis or treatment plan. Such systems usually use one of three mechanisms of analysis alone or in combination: classification trees, Bayesian conditional probabilities, or rule-based (heuristic) systems. Numerous problems must be solved before decision-support systems will become commonplace in clinical practice. Data entry of patients' signs and symptoms is often tedious. The quality of the clinician's initial observations is of great importance in determining the quality of the output. It is also often difficult to convey to a program the subtlety of clinical information observed. Knowledge required in clinical data bases is often unavailable or imprecise. As these and other challenges are addressed we can anticipate increased utility of decision support programs in the future.
The demographics of ultraluminous X-ray sources

Results of recent statistical studies of the population of ultraluminous X-ray sources are presented. Special emphasis is placed on the outcome of a complete survey of 140 nearby galaxies hosting 114 ULXs. It is shown that ULXs are preferentially associated with young star-forming regions but not necessarily with massive young clusters, that ULXs occur at a higher rate (per unit mass) in dwarf galaxies compared to giant galaxies and that ULXs rarely occur in galactic halos. If an upper limit to the luminosity of ULXs exists, then it must be above several times 1040 erg s–1 in the X-ray band. The luminosity function is still too sparsely sampled above this luminosity for a more definitive statement to be made (© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
Uncertainty Quantification of Structural Response Using Evidence Theory

Over the past decade, classical probabilistic analysis has been a popular approach among the uncertainty quantification methods. As the complexity and performance requirements of a structural system are increased, the quantification of uncertainty becomes more complicated, and various forms of uncertainties should be taken into consideration. Because of the need to characterize the distribution of probability, classical probability theory may not be suitable for a large complex system such as an aircraft, in that our information is never complete because of lack of knowledge and statistical data. Evidence theory, also known as Dempster-Shafer theory, is proposed to handle the epistemic uncertainty that stems from lack of knowledge about a structural system. Evidence theory provides us with a useful tool for aleatory (random) and epistemic (subjective) uncertainties. An intermediate complexity wing example is used to evaluate the relevance of evidence theory to an uncertainty quantification problem for the preliminary design of airframe structures. Also, methods for efficient calculations in large-scale problems are discussed.
Outcome Studies Among Men With Micropenis

Adult stretched penile length (SPL) was determined among 22 males who were diagnosed with micropenis. These adult SPL values were compared with SPL at the time of diagnosis, age of diagnosis and etiologic category in 20 men who were diagnosed before puberty. A portion of this group completed a structured questionnaire interview, the Social Adjustment Self Report Questionnaire and the Hopkins Symptom Checklist to assess social and psychosexual milestones and the presence of psychiatric morbidity. Results show that the majority of men who had been diagnosed with micropenis had an adult SPL within 2 standard deviations of the normal adult mean, with only a minority showing values below this. It appeared that men with micropenis might have greater than average interval SPL growth between diagnosis and adulthood; it remains unclear whether this supranormal growth represents a catch-up phenomenon or results from augmentation by intermittent androgen therapy. There was no clear relationship between SPL at diagnosis and SPL in adulthood. The responses to the questionnaires indicated that men who had been diagnosed with micropenis were comparable to control men in regard to gender issues, body image, social fitness, sexuality, work, family adjustment and the presence of psychopathology.
What’s Going on with These Lithium Reagents?

This Perspective describes a series of research projects that led the author from an interest in lithium reagents as synthetically valuable building blocks to studies aimed at understanding the science behind the empirical art developed by synthetic chemists trying to impose their will on these reactive species. Understanding lithium reagent behavior is not an easy task; since many are mixtures of aggregates, various solvates are present, and frequently new mixed aggregates are formed during their reactions with electrophiles. All of these species are typically in fast exchange at temperatures above −78 °C. Described are multinuclear NMR experiments at very low temperatures aimed at defining solution structures and dynamics and some kinetic studies, both using classic techniques as well as the rapid inject NMR (RINMR) technique, which can in favorable cases operate on multispecies solutions without the masking effect of the Curtin–Hammett principle.
A kinetic separation method for the stereoselective preparation of (Z)- and (E)-monofluoroenynes from E/Z mixtures of 1-bromo-1-fluoroolefins

Abstract Reaction of E/Z mixtures of 1-bromo-1-fluoroolefins with 1-alkynes and catalytic Pd(PPh3)2Cl2 and CuI in triethylamine at room temperature gave (after 16–24 h) predominately the (Z)-monofluoroenyne (Z/E>92/8) in good yields. Pure (Z)-monofluoroenyne could generally be obtained by chromatographic separation of the crude Z/E mixture. Pure (Z)-1-bromo-1-fluoroolefin could he recovered and reacted with 1-alkynes under similar conditions and longer reaction times (48 h) to give pure (E)-monofluoroenynes in excellent yields (78–89%). Thus, E/Z mixtures of 1-bromo-1-fluoroolefins could be kinetically separated into (Z)- and (E)-monofluoroenynes. This methodology provides a simple one-step unequivocal route to the isomerically pure (Z)- and (E)-monofluoroenynes from the readily available 1-bromo-1-fluoroolefins.
BOUND STATES BETWEEN TWO PARTICLES IN A TWO- OR THREE-DIMENSIONAL INFINITE LATTICE WITH ATTRACTIVE KRONECKER δ-FUNCTION INTERACTION

The bound state energy and wave function for two particles in a 2- or 3-dimensional infinite lattice with attractive Kronecker δ-function interaction are discussed.
Vanishing lines in generalized Adams spectral sequences are generic

We show that in a generalized Adams spectral sequence, the presence of a vanishing line of xed slope (at some term of the spectral sequence, with some intercept) is a generic property.
Diffuse X-Rays from the Arches and Quintuplet Clusters

The origin and initial mass function of young stellar clusters near the Galactic center are still poorly understood. Two of the more prominent ones, the Arches and Quintuplet clusters, may have formed from a shock-induced burst of star formation, given their similar age and proximity to each other. Their unusual mass distribution, however, may be evidence of a contributing role played by other factors, such as stellar capture from regions outside the clusters themselves. Diffuse X-ray emission from these sources provides us with a valuable, albeit indirect, measure of the stellar mass-loss rate from their constituents. Using recent data acquired with Chandra, we can study the nature and properties of the outflow to not only probe the pertinent physical conditions, such as high metallicity, the magnetic field, and so forth, but also to better constrain the stellar distribution within the clusters, in order to identify their formative history. In this paper, we present a set of three-dimensional smoothed particle hydrodynamics simulations of the wind-wind interactions in both the Arches and Quintuplet clusters. We are guided primarily by the currently known properties of the constituent stars, though we vary the mass-loss rates in order to ascertain the dependence of the measured X-ray flux on the assumed stellar characteristics. Our results are compared with the latest observations of the Arches cluster. Our analysis of the Quintuplet cluster may be used as a basis for comparison with future X-ray observations of this source.
Adaptive Distributed Dynamic Channel Allocation for Wireless Networks

Channel allocation schemes in a mobile computing (wireless) environment can be either static or dynamic. Static allocation offers negligible channel acquisition time and zero message complexity and works well at a low system load; the performance steadily decreases as system load increases since many calls are dropped. In the case of even temporary hot spots many calls may be dropped by a heavily loaded switching station even when there are enough idle channels in the interference region of that station. On the other hand, dynamic schemes provide better utilization of the channels at higher loads albeit at the cost of higher channel acquisition time and some additional control messages. Our purpose in the present paper is to propose a combined channel allocation scheme so that each switching station can tune to its own load independent of other stations in its interference region; the objective is to minimize the call drop rate and at the same time maintain a minimum average channel acquisition time and minimum control message complexity.
Near-Horizon Virasoro Symmetry and the Entropy of de Sitter Space in Any Dimension

De Sitter spacetime is known to have a cosmological horizon that enjoys thermodynamic-like properties similar to those of a black hole horizon. In this note we show that a universal argument can be given for the entropy of de Sitter spacetime in arbitrary dimensions, by generalizing a recent near horizon symmetry plus conformal field theory argument of Carlip for black hole entropy. The implications of this argument are also discussed.
Hadronic spectrum in inclusive semileptonic B decays

Abstract We evaluate the inclusive semileptonic B decay spectrum as a function of the final-state hadrons energy to second order in the inverse quark mass expansion and tree level in α s . We argue that there is an energy interval below the c production threshold that could be used to determine V ub .
Automating embedded analysis capabilities and managing software complexity in multiphysics simulation, Part I: Template-based generic programming

An approach for incorporating embedded simulation and analysis capabilities in complex simulation codes through template-based generic programming is presented. This approach relies on templating and operator overloading within the C++ language to transform a given calculation into one that can compute a variety of additional quantities that are necessary for many state-of-the-art simulation and analysis algorithms. An approach for incorporating these ideas into complex simulation codes through general graph-based assembly is also presented. These ideas have been implemented within a set of packages in the Trilinos framework and are demonstrated on a simple problem from chemical engineering.
Ribbon Schur operators

A new combinatorial approach to the ribbon tableaux generating functions and q-Littlewood-Richardson coefficients of Lascoux et al. [A. Lascoux, B. Leclerc, J.-Y. Thibon, Ribbon tableaux, Hall-Littlewood symmetric functions, quantum affine algebras, and unipotent varieties, J. Math. Phys. 38 (3) (1997) 1041-1068] is suggested. We define operators which add ribbons to partitions and following Fomin and Greene [S. Fomin, C. Greene, Noncommutative Schur functions and their applications, Discrete Math. 193 (1998) 179-200] study non-commutative symmetric functions in these operators. This allows us to give combinatorial interpretations for some (skew) q-Littlewood-Richardson coefficients whose non-negativity appears not to be known. Our set-up also leads to a new proof of the action of the Heisenberg algebra on the Fock space of U"q(sl@^"n) due to Kashiwara et al. [M. Kashiwara, T. Miwa, E. Stern, Decomposition of q-deformed Fock spaces, Selecta Math. 1 (1996) 787-805].
Building an application-aware IPsec policy system

As a security mechanism at the network-layer, the IP security protocol (IPsec) has been available for years, but its usage is limited to Virtual Private Networks (VPNs). The end-to-end security services provided by IPsec have not been widely used. To bring the IPsec services into wide usage, a standard IPsec API is a potential solution. However, the realization of a user-friendly IPsec API involves many modifications on the current IPsec and Internet Key Exchange (IKE) implementations. An alternative approach is to configure application-specific IPsec policies, but the current IPsec policy system lacks the knowledge of the context of applications running at upper layers, making it infeasible to configure application-specific policies in practice. In this paper, we propose an application-aware IPsec policy system on the existing IPsec/IKE infrastructure, in which a socket monitor running in the application context reports the socket activities to the application policy engine. In turn, the engine translates the application policies into the underlying security policies, and then writes them into the IPsec Security Policy Data-base (SPD) via the existing IPsec policy management interface. We implement a prototype in Linux (Kernel 2.6) and evaluate it in our testbed. The experimental results show that the overhead of policy translation is insignificant, and the overall system performance of the enhanced IPsec is comparable to those of security mechanisms at upper layers. Configured with the application-aware IPsec policies, both secured applications at upper layers and legacy applications can transparently obtain IP security enhancements.
Correlation as a global measure of geomagnetic activity: Phase boundaries and a precedent line of nodes

[1] This work considers the global correlation of geomagnetic activity as a way to evaluate magnetotail disturbances, such as the substorm. Impulsive magnetotail disturbances are generally associated with geomagnetic pulsations, which can be coherent over wide ranges of latitude and longitude, and which display distinctive phase reversals collocated with power maxima. Analyzing a disturbance period chosen for its breadth in local time, we find that pulsations can be detected from the coherence that they generate within a magnetometer array, and identify an extended line of nodes across which the phase reversals occur. Phase reversals consistent with the same line of nodes persist for five hours, beginning clearly in a 0.7 mHz pulsation one and a half hours before the disturbance, and persisting in a 5.8 mHz pulsation three and one half hours after the initial disturbance. Under the hypothesis that the line of nodes maps to a source in the central plasma sheet (CPS), we note that the persistence of this extended source of disturbances suggests memory in the CPS. We define a quantitative “coherence index” that characterizes geomagnetic activity according to the degree of global coherence that it generates, and observe that a narrowly peaked coherence signal leads a much broader peak in power. We relate these results to models of the magnetosphere based in critical phenomena.
The 5-HT7 receptor as a potential target for treating drug and alcohol abuse.

Alcohol and drug abuse take a large toll on society and affected individuals. However, very few effective treatments are currently available to treat alcohol and drug addiction. Basic and clinical research has begun to provide some insights into the underlying neurobiological systems involved in the addiction process. Several neurotransmitter pathways have been implicated and distinct reward neurocircuitry have been proposed – including the mesocorticolimbic (MCL) dopamine system and the extended amygdala. The serotonin (5-HT) neurotransmitter system is of particular interest and multiple 5-HT receptors are thought to play significant roles in alcohol and drug self-administration and the development of drug dependence. Among the 5-HT receptors, the 5-HT-7 receptor is currently undergoing characterization as a potential target for the treatment of several psychiatric disorders. Although this receptor has received only limited research regarding addictive behaviors, aspects of its neuroanatomical, biochemical, physiological, pharmacological, and behavioral profiles suggest that it could play a key role in the addiction process. For instance, genomic studies in humans have suggested a link between variants in the gene encoding the 5-HT-7 receptor and alcoholism. Recent behavioral testing using high-affinity antagonists in mice and preliminary tests with alcohol-preferring rats suggest that this receptor could mediate alcohol consumption and/or reinforcement and play a role in seeking/craving behavior. Interest in the development of new and more selective pharmacological agents for this receptor will aid in examining the 5-HT-7 receptor as a novel target for treating addiction.
The Harder–Narasimhan stratification of the moduli stack of G-bundles via Drinfeld’s compactifications

We use Drinfeld’s relative compactifications \({\overline{\mathop {{\mathrm{Bun}}}\nolimits }}_P\) and the Tannakian viewpoint on principal bundles to construct the Harder–Narasimhan stratification of the moduli stack \(\mathop {{\mathrm{Bun}}}\nolimits _G\) of \(G\)-bundles on an algebraic curve in arbitrary characteristic, generalizing the stratification for \(G=\mathop {\mathrm{GL}}\nolimits _n\) due to Harder and Narasimhan to the case of an arbitrary reductive group \(G\). To establish the stratification on the set-theoretic level, we exploit a Tannakian interpretation of the Bruhat decomposition and give a new and purely geometric proof of the existence and uniqueness of the canonical reduction in arbitrary characteristic. We furthermore provide a Tannakian interpretation of the canonical reduction in characteristic \(0\) which allows to study its behavior in families. The substack structures on the strata are defined directly in terms of Drinfeld’s compactifications \({\overline{\mathop {{\mathrm{Bun}}}\nolimits }}_P\), which we generalize to the case where the derived group of \(G\) is not necessarily simply connected. Using \({\overline{\mathop {{\mathrm{Bun}}}\nolimits }}_P\), we establish various properties of the stratification, including finer information about the structure of the individual strata and a simple description of the strata closures.
Development and application of tools to characterize the oxidative degradation of AP/HTPB/Al propellants in a propellant reliability study

Abstract The oxidative thermal aging of a cross-linked hydroxyl-terminated polybutadiene (HTPB)/isophorone diisocyanate (IPDI) polyurethane rubber was studied at temperatures between 25 and 125 °C. Changes in tensile elongation, mechanical hardening, polymer network properties, density, O 2 permeation and molecular chain dynamics were investigated as a function of age. The techniques used include solvent swelling, detailed modulus profiling, and NMR relaxation measurements. The Arrhenius methodology, which normally assumes a linear extrapolation of high temperature aging data, is critically evaluated by using extensive data superposition and highly sensitive oxygen consumption measurements. Significant curvature in the Arrhenius diagram of these oxidation rates is observed to be similar to previous results found for other rubber materials that have been evaluated by this technique. Preliminary gel/network properties suggest that cross-linking is the dominant process at higher temperatures. The effect on the oxidation rate of the binder when other constituents found in propellants are present, such as ammonium perchlorate (AP), plasticizer and aluminum powder, is presented.
Money, money, money? A longitudinal investigation of entrepreneur career reasons, growth preferences and achieved growth

This paper longitudinally examines the relationship between the career reasons of nascent entrepreneurs, their growth preferences and subsequent growth achieved. The longitudinal design allows for examination and control of both survivorship and recall bias upon career reason and growth linkages. Substantial recall bias was observed in the career reasons of entrepreneurs, with the reported importance of self-realization and financial success, as explanations for entering venturing activity, being significantly lower when responses were obtained once the venture was operational. Consistent with economic motives, the importance that the entrepreneur places on financial success was a key determinant to explain cross-sectional differences in growth preferences of the entrepreneur, the intended size of the venture, and achieved growth. Further, the importance of financial success was robust to the use of both prospective and retrospective career reasons. While independence was the most important factor to expl...
Asserting and checking determinism for multithreaded programs

The trend towards processors with more and more parallel cores is increasing the need for software that can take advantage of parallelism. The most widespread method for writing parallel software is to use explicit threads. Writing correct multithreaded programs, however, has proven to be quite challenging in practice. The key difficulty is nondeterminism. The threads of a parallel application may be interleaved nondeterministically during execution. In a buggy program, nondeterministic scheduling can lead to nondeterministic results—where some interleavings produce the correct result while others do not. We propose an assertion framework for specifying that regions of a parallel program behave deterministically despite nondeterministic thread interleaving. Our framework allows programmers to write assertions involving pairs of program states arisingfrom different parallel schedules. We describe an implementation of our deterministic assertions as a library for Java, and evaluate the utility of our specifications on a number of parallel Java benchmarks. We found specifying deterministic behavior to be quite simple using our assertions. Further, in experiments with our assertions, we were able to identify two races as true parallelism errors that lead to incorrect non-deterministic behavior. These races were distinguished from a number of benign races in the benchmarks.
A novel synthesis of 3-(substituted)pyrimido[4,5-c]pyridazine-5,7(1H,6H)-diones

An improved synthesis of 3-(substituted)pyrimido[4,5-c]pyridazine-5,7(1H,6H)-diones, a known subclass of 4-deazatoxoflavins, is reported. The approach involves treatment of 3-methyl-6-(1-methylhydrazinyl) uracil with representative phenyl and alkyl glyoxal monohydrates, which in turn are obtained by selenium dioxide oxidation of the corresponding phenyl and alkyl methyl ketones. The first entry into 4-monosubstituted isomers is also reported.
Detecting Dark Matter-Dark Energy Coupling with the Halo Mass Function

We use high-resolution simulations of large-scale structure formation to analyze the effects of interacting dark matter and dark energy on the evolution of the halo mass function. Using a χ2 likelihood analysis, we find significant differences in the mass function between models of coupled dark matter-dark energy and standard concordance cosmology (ΛCDM) out to redshift z = 1.5. We also find a preliminary indication that the Dark Energy Survey (DES) should be able to distinguish these models from ΛCDM within its mass and redshift constraints. While we can distinguish the effects of these models from ΛCDM cosmologies with different fundamental parameters, DES will require independent measurements of σ8 to confirm these effects.
The absorption coefficient for slow electrons in gases

Electrons from a heated filament were accelerated through a slit and deflected magnetically around a circular path into a Faraday cylinder connected to a galvanometer. From the plots of the logarithm of the ratio of the galvanometer current G to the total electron current M from the filament, as a function of the pressure, the absorption coefficients were determined for various accelerating voltages from 2 to 360. For a given voltage, the absorption coefficient was found to be independent of the current M and also of the pressure (at about 10^-2 mm). The results of Mayer and Ramsauer were checked for argon and helium. In argon, the coefficient reaches a sharp maximum at about 12 volts, the value for 2 volts being only one-fifth of the maximum value. In helium there is a maximum at 4 volts. Methane gave a curve similar to these, with a maximum at about 7.5 volts, which is in agreement with the results of Akesson. The curves for nitrogen and carbon monoxide are nearly identical, both having a maximum at about 18 volts and a minimum at about 9 volts. The curve for hydrogen shows no maximum, the coefficient increasing steadily down to 2 volts.
Zinc released from olfactory bulb glomeruli by patterned electrical stimulation of the olfactory nerve

Zinc is a trace element with a multitude of roles in biological systems including structural and cofactor functions for proteins. Although most zinc in the central nervous system (CNS) is protein bound, the CNS contains a pool of mobile zinc housed in synaptic vesicles within a subset of neurons. Such mobile zinc occurs in many brain regions, such as the hippocampus, hypothalamus, and cortex, but the olfactory bulb (OB) contains one of the highest such concentrations in the CNS. Zinc is distributed throughout the OB, with the glomerular and granule cell layers containing the highest levels. Here, we visualize vesicular zinc in the OB using zinc-responsive fluorescent probes developed by one of us. Moreover, we provide the first demonstration that vesicular pools of zinc can be released from olfactory nerve terminals within individual glomeruli by patterned electrical stimulation of the olfactory nerve designed to mimic the breathing cycle in rats. We also provide electrophysiological evidence that elevated extracellular zinc potentiates α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor-mediated synaptic events. AMPA receptors are required for the synchronous activation of neurons within individual OB glomeruli, and zinc-mediated potentiation leads to enhanced synaptic summation.
Synthesis of the ravidomycin ring system

Abstract Synthesis of the tetracyclic aromatic ring system of the ravidomycin family of anti-tumor agents is reported. The synthesis is a sequential Meerwein and Diels-Alder route with the crucial regiochemistry of the Diels-Alder reaction controlled with a chlorine atom.
Three Occurrences of the Hyperbolic-Secant Distribution

Although it is the generator distribution of the sixth natural exponential family with quadratic variance function, the Hyperbolic-Secant (HS) distribution is much less known than other distributions in the exponential families. Its lack of familiarity is due to its isolation from many widely used statistical models. We fill in the gap by showing three examples naturally generating the HS distribution, including Fisher’s analysis of similarity between twins, the Jeffreys’ prior for contingency tables, and invalid instrumental variables.
In vivo retinal blood flow measurement by Fourier domain Doppler optical coherence tomography

The measurement of ocular blood flow is important in studying the pathophysiology and treatment of several leading causes of blindness. We present a method for in vivo human retinal flow measurement using Fourier domain optical coherence tomography. A double circular scanning pattern was used to scan the blood vessels around the optic nerve head 8 times over 2 seconds. The venous flow totaled 36.13 μl/min in the right eye of a volunteer. The flow difference was observed before and after breath holding. The fast flow measurement method did not require any assumption on the flow profile over time or space.© (2008) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Anomalous physical transport in complex networks.

The emergence of scaling in transport through interconnected systems is a consequence of the topological structure of the network and the physical mechanisms underlying the transport dynamics. We study transport by advection and diffusion in scale-free and Erd\ifmmode \mbox{\H{o}}\else \H{o}\fi{}s-R\'enyi networks. Velocity distributions derived from a flow potential exhibit power-law scaling with exponent $\ensuremath{\nu}\ensuremath{\approx}\ensuremath{\gamma}+1$, where $\ensuremath{\gamma}$ is the exponent of network connectivity. Using stochastic particle simulations, we find anomalous (nonlinear) scaling of the mean-square displacement with time. We show the connection with existing descriptions of anomalous transport in disordered systems, and explain the mean transport behavior from the coupled nature of particle jump lengths and transition times.
Self-similarity of contact line depinning from textured surfaces

The mobility of drops on surfaces is important in many biological and industrial processes, but the phenomena governing their adhesion, which is dictated by the morphology of the three-phase contact line, remain unclear. Here we describe a technique for measuring the dynamic behaviour of the three-phase contact line at micron length scales using environmental scanning electron microscopy. We examine a superhydrophobic surface on which a drop's adhesion is governed by capillary bridges at the receding contact line. We measure the microscale receding contact angle of each bridge and show that the Gibbs criterion is satisfied at the microscale. We reveal a hitherto unknown self-similar depinning mechanism that shows how some hierarchical textures such as lotus leaves lead to reduced pinning, and counter-intuitively, how some lead to increased pinning. We develop a model to predict adhesion force and experimentally verify the model's broad applicability on both synthetic and natural textured surfaces.
Does interfirm modularity complement ignorance? A field study of software outsourcing alliances

Knowledge-intensive outsourcing alliances present outsourcers with a tension between simultaneously sharing enough private knowledge to accomplish alliance goals and safeguarding such knowledge against misappropriation. This study explores the perspective that increasing interfirm modularity lowers the need for interfirm knowledge sharing. Put another way, modularity complements outsourcee ignorance. Analyses of data on 209 alliances between U.S. firms and software services firms in Russia, Ireland, and India provide strong support for this idea. Our theoretical elaboration and empirical testing of the complementarities between modularity and outsourcee ignorance has significant implications for strategy theory, which are also discussed. Copyright © 2008 John Wiley & Sons, Ltd.
A convenient synthesis of porphodimethenes and their conversion to trans-porphyrins with two functionalized meso-naphthyl substituents

The Mac Donald-type 2 + 2 condensation of the readily available 5-mesityldipyrromethane with acenaphthenequinone leads to the trans (syn and anti) porphodimethenes, respectively, which, after treatment with KOH or NaOMe in THF and subsequent oxidation with air, yield the corresponding trans-8-carboxynaphthylporphyrins or their esters.
Statistics of giant arcs in galaxy clusters

We study the expected properties and statistics of giant arcs produced by galaxy clusters in a ΛCDM (cold dark matter) universe and investigate how the characteristics of CDM clusters determine the properties of the arcs they generate. Because of the triaxiality and substructure of CDM halos, the giant-arc cross section for individual clusters varies by more than an order of magnitude as a function of viewing angle. In addition, the shallow density cusps and triaxiality of CDM clusters cause systematic alignments of giant arcs that should be testable with larger samples from forthcoming lensing surveys. We compute the predicted statistics of giant arcs for the ΛCDM model and compare them with results from previous surveys. The predicted arc statistics are in excellent agreement with the numbers of giant arcs observed around low-redshift (0.2 z 0.6) clusters from the Extended Medium-Sensitivity Survey sample; however, there are hints of a possible excess of arcs observed around high-redshift (z 0.6) clusters. This excess, if real, appears to be due to the presence of highly massive or concentrated clusters at high redshifts.
Increasing wireless revenue with service differentiation

New technologies such as IEEE 802.16 (Wi-MAX) [2] and IEEE 802.11e (Wi-Fi with QoS) [1] enable differentiated services. In this study we explore the potential for increasing the revenue of Internet service providers with differentiated services. For concreteness, we focus on two generic services that we call "voice" and "data." However, the analysis applies to services that have different requirements such as video streaming and networked games. Using analytical models we examine the conditions under which the operator can improve his revenue with service differentiation. We verify the results using a simulation of a more complex model of the network.
The Economic Effects of Legal Restrictions on High-Cost Mortgages

We analyze the effects of state predatory mortgage lending laws, which have been a model for recent changes in the United States federal legislation enacted to regulate the mortgage contract terms common in higher-risk mortgage market segments. Using the Rothschild-Stiglitz approach to model credit markets under asymmetric information, legal restrictions are shown to reduce the use and attractiveness of mortgage credit. Consistent with model predictions, empirical results indicate that originations of regulated high-cost mortgages were significantly less than predicted in states with more restrictive laws. The differences between predicted and actual originations of high-cost mortgages in states with less restrictive laws were not significant. These differences were also not significant for non-high-cost originations across all states. Thus, credit regulation was differentially associated with reduction in originations of high-cost mortgages, and non-high-cost lending did not consistently expand in areas where high-cost mortgages were restricted.
A library is not the books: an ethical obstacle to the digital library

Purpose – The purpose of this paper is to demonstrate that libraries do not inevitably arise from the aggregation of information, and to apply this result to critique the meaningfulness of the idea of a “digital library.”Design/methodology/approach – Three independent arguments demonstrate that libraries are more than the sum of the books that they contain: first, the logical argument, which analyses the internal consistency of claims for the superiority of electronic formats; second, the semantic argument, which examines ordinary language to isolate the core requirements of what it means to be a “library”; and third, the ethical argument, which identifies the source of the unique phenomenological experience of encounter with the library.Findings – It is found that the three arguments each refute the view that “library” is the collective noun for “book,” and argue instead that it is an emergent concept that offers to its community a reflection of the local cultural knowledge through the ordinary selection...
Collinear two-color saturation spectroscopy in CN A–X (1–0) and (2–0) bands

Abstract Hyperfine-resolved saturation spectra were measured for a selection of low and medium J rotational lines in the A 2Π–X 2Σ+ system of CN using two copropagating laser beams tuned to transitions in the (2–0) and (1–0) bands. A bleach laser was amplitude modulated and fixed in frequency near the center of a rotational line of the (2–0) vibrational band, while a probe laser was frequency-modulated and scanned across selected lines of the (1–0) vibrational band, sharing a common lower state with the bleach laser. Locking the probe laser with a tunable radio frequency offset to a cavity that tracks the slowly drifting bleach laser greatly improved the quality of the double-resonance saturation signals, by stabilizing the relative frequency of the two beams. The sub-Doppler resonances were fit with Lorentzian line shapes having a typical full-width at half maximum of 2–3 MHz. The hyperfine spectra observed depend on the hyperfine structure within both rovibronic transitions excited, permitting the determination of hyperfine molecular constants in the υ = 2 state and the refinement of previously published values in the υ = 1 state. Four nuclear magnetic dipole and two electric quadrupole hyperfine constants were determined for each of the upper states from a fit with a weighted root mean squared error of 0.5 MHz. The vibrational dependence of these constants is weak or negligible.
The relation of central 5-HT1A and 5-HT2 receptors: low dose agonist-induced selective tolerance in the rat.

Abstract To study the purported relation of 5-HT 1A and 5-HT 2 receptors, we chronically injected rats with a low dose of selective 5-HT agonists to induce behavioral tolerance and then tested for cross-tolerance. Acutely, in naive rats, both the putative 5-HT 2 agonist DOI and 5-HT 1A agonist 8-OH-DPAT induced some behaviors of the “serotonin syndrome” but the two drugs could be differentiated. Only DOI evoked shaking behavior, “skin jerks” (spinal myoclonus), and hyperthermia. Only 8-OH-DPAT induced flat body posture, head weaving, hypothermia, and occasional hindlimb hyperextension (dystonic posture). Both drugs, especially 8-OH-DPAT, evoked forepaw taping. Chronic (21 day) treatment with DOI prevented DOI-evoked behaviors but not behaviors evoked by 8-OH-DPAT. Behaviors evoked by 8-OH-DPAT and not DOI decreased significantly after chronic 8-OH-DPAT treatment. Development of selective tolerance suggests that putative selective 5-HT 2 and 5-HT 1A agonists exert shared and distributive behavioral effects through separate sites whose relation is behavior-specific. For some behaviors (forepaw myoclonus, shaking behavior, thermoregulation), there is functional interaction between 5-HT 1A and 5-HT 2 sites, while for other behaviors (skin jerks, flat body posture, head weaving), there is no interaction.
FPTAS for #BIS with Degree Bounds on One Side

Counting the number of independent sets for a bipartite graph (#BIS) plays a crucial role in the study of approximate counting. It has been conjectured that there is no fully polynomial-time (randomized) approximation scheme (FPTAS/FPRAS) for #BIS, and it was proved that the problem for instances with a maximum degree of 6 is already as hard as the general problem. In this paper, we obtain a surprising tractability result for a family of #BIS instances. We design a very simple deterministic fully polynomial-time approximation scheme (FPTAS) for #BIS when the maximum degree for one side is no larger than 5. There is no restriction for the degrees on the other side, which do not even have to be bounded by a constant. Previously, FPTAS was only known for instances with a maximum degree of 5 for both sides.
The influence of environment on fatigue crack growth of an Fe3Al, Cr alloy

Abstract The fatigue crack growth resistance, fracture toughness and notch sensitivity of an Fe 3 Al alloy containing 4.8 at% Cr are reported. Crack growth behaviour is adversely affected by moisture, hydrogen gas, and hydrogen charged electrolytically. Dry oxygen provides the highest crack growth thresholds and lowest crack growth rates. High vacuum is not quite as effective as oxygen in suppressing embrittlement, supporting the view that the formation of oxide films effectively inhibits hydrogen ingress. In general, fatigue crack growth was more rapid in the DO 3 condition in each environment. Fractographic features are discussed.
Adding mystery to the case of the missing currency

Abstract The Fedeal Reserve Bank reports that approximately $300 billion worth of United States currency was in circulation in 1992. Yet based on household survey and other information, households and firms in the country claim to hold only a fifth of this total. A recent article by Sprenkle argues that the “missing currency” is largely held outside the United States. It is implausible that most of the missing currency is held outside the United States; with simple adjustments we are able to explain the whereabouts of about half of all the currency in circulation. Even these adjustments would imply very large overseas holdings of dollars, so we suspect that people hold surprisingly large amounts of currency; why this should be so is not yet fully understood.