cssi/SciSciGPT-SciSciNet huggingface dataset:
Dielectrophoretic tweezers as a platform for molecular force spectroscopy in a highly parallel format

Miniaturization has driven down the cost of tools used in bioanalysis and diagnostics, with single molecules becoming the ultimate detection limit. Our aim is to build a force-spectroscopy-on-a-chip device that can detect and manipulate many (millions) single molecules in parallel. We demonstrate placement of single DNA molecules on a surface with controlled spacing and subsequent attachment of microscopic force probes to those molecules. We used dielectrophoresis (DEP) in a simple planar-electrode geometry as a form of molecular force spectroscopy in a highly parallel format. We determined the approximate crossover frequency between negative and positive DEP using electrodes without dielectric microstructures — a simplification over standard experimental methods involving quadrupoles or optical trapping. We applied the DEP tweezers to the stretching of a short DNA oligomer and detected its extension using total-internal reflection fluorescence microscopy. The combination of a simple device fabrication, molecule-bead alignment, uniform distribution of high axial forces, and simultaneous detection of molecular extensions makes DEP tweezers ideal for highly parallel detection of stretching or unbinding of biomolecules.
A Note on Mirror Symmetry for Manifolds with Spin(7) Holonomy

Starting from the extended worldsheet superconformal algebras associated with G2 manifolds, we extend the algebra to Joyce's orbifolds with holonomy. We show how the mirror symmetry in manifolds with holonomy arises as the automorphism in the extended sperconformal algebra. In one class of Joyce's orbifolds, the automorphism of the superconformal algebra can be realized as 14 kinds of T-dualities along the supersymmetric T4 toroidal fibrations in the manifolds with holonomy. In this class of examples, Joyce's orbifolds are pairwise identified under the mirror symmetry. We then discuss some interesting features of the mirror symmetry on the manifolds with exceptional holonomy and how it is different from the Calabi–Yau mirror symmetry.
Interpreting the Mg?II h and k Line Profiles of Mira Variables

We use radiative transfer calculations to reproduce the basic appearance of Mg II lines observed from Mira variables. These lines have centroids that are blueshifted by at least 30 km s-1 from the stellar rest frame. It is unlikely that flow velocities in the stellar atmospheres are this fast, so radiative transfer effects must be responsible for this behavior. Published hydrodynamic models predict the existence of cool, downflowing material above the shocked material responsible for the Mg II emission, and we demonstrate that scattering in this layer can result in Mg II profiles as highly blueshifted as those that are observed. However, our models also show that scattering within the shock plays an equally strong role in shaping the Mg II profiles, and our calculations illustrate the importance of partial redistribution and the effects of being out of ionization equilibrium.
Depinning of Charge-Density Waves by Quantum Tunneling

A review of the basic theories that have been given for charge transport by the Frohlich mechanism of moving charge-density waves is given in this book in the chapter by Fukuyama and Takayama. This chapter will review the theory of and evidence for depinning of incommensurate CDWs that are pinned by weak impurities by quantum tunneling. By weak is meant that a single impurity cannot pin the phase of the wave but pinning results from fluctuations in impurity concentration as suggested by the theories of Fukuyama and Lee [1] and Lee and Rice [2].
Nationalism, Patriotism, and Cosmopolitanism in an Age of Globalization

A major issue in political philosophy is the extent to which one or another version of nationalism or, by contrast, cosmopolitanism, is morally justified. Nationalism, like cosmopolitanism, may be understood as a position on the status and responsibilities of nation states, but the terms may also be used to designate attitudes appropriate to those positions. One problem in political philosophy is to distinguish and appraise various forms of nationalism and cosmopolitanism; a related problem is how to understand the relation of patriotism to each. Nationalists may tend to be patriots, but need not be; patriots may tend to be nationalists, but need not be. Like nationalism, patriotism may also be considered in propositional forms or in related attitudinal forms; but unlike nationalism and cosmopolitanism, patriotism can exist in the form of an emotion: roughly, love of one’s country. This paper characterizes nationalism, cosmopolitanism, and patriotism in both forms and argues for a conception of patriotism on which it is both distinct from nationalism and compatible with certain kinds of cosmopolitanism. It also suggests that, in qualified forms, nationalism and cosmopolitanism may overlap in what they require of their proponents.
A stepwise mechanism for gas-phase unimolecular ion decompositions. Isotope effects in the fragmentation of tert-butoxide anion

Infrared multiple photon (IRMP) photochemical activation of gas-phase ions trapped in an ion cyclotron resonance (ICR) spectrometer has been used to study the mechanism of a gas-phase negative ion unimolecular decomposition. Upon irradiation with a CO/sub 2/ laser (both high-power pulsed and low-power continuous wave (CW)), tert-butoxide anion, trapped in a pulsed ICR spectrometer, decomposes to yield acetone enolate anion and methane. The mechanism of this formal 1,2-elimination reaction was probed by measuring competitive hydrogen isotope effects (both primary and secondary) in the IR laser photolysis of 2-methyl-2-propoxide-1,1,1-d/sub 3/ (1) and 2-methyl-2-propoxide-1,1,1,3,3,3-d/sub 6/ (2) anions. Unusually large secondary isotope effects (pulsed laser, 1.9 for 1 and 1.7 for 2; cw laser, 8 for (1) and small primary isotope effects (pulsed laser, 1.6 for 1 and 2; cw laser, 2.0 for (1) were observed. These isotope effects, particularly the large difference in energy dependence of the primary and secondary effects, are consistent only with a stepwise mechanism involving initial bond cleavage to an intermediate ion-molecular complex followed by a hydrogen transfer within the intermediate complex. The observed secondary isotope effect have been modelled by using statistical reaction rate (RRKM) theory. The implications of this study for several previously reported unimolecular ionmore » decompositions are also discussed.« less
Seasonal variations in diffuse, monoenergetic, and broadband aurora

[1] The only previously established seasonal auroral variation is that of intense monoenergetic aurora, corresponding to quasi-static acceleration by geomagnetic-field-aligned electric fields. Here we investigate the separate seasonal dependence of both types of electron accelerated aurora (broadband, or wave, in addition to monoenergetic) and both ion and electron diffuse aurora. Dayside and nightside variations are separately considered, as are conditions of low and high solar wind driving. Across these many combinations, several clear patterns emerge. One is that the dayside tends to maximize precipitation in the summer and much more so for low solar wind driving. Nightside precipitation is higher in the winter and much more so for high solar wind driving. The dayside effects are strongest in number flux and stronger in diffuse aurora than accelerated aurora. The ease of ion entry through the summer cusp, along with the constraints of charge quasi-neutrality, and the rise in dayside currents in the summer hemisphere adequately explain much (perhaps all) of the dayside behavior. Nightside effects are more apparent in energy flux, with the winter/summer ratio of monoenergetic aurora being the largest: 1.70 for high solar wind driving. However, both other types of electron aurora, diffuse (1.30) and broadband (1.26), also have winter/summer energy fluxes well above unity for high solar wind driving. The nightside seasonal variation of ions is much smaller, with slightly more energy flux postmidnight in the winter but with slightly higher energy fluxes premidnight in the summer. Since the increased nightside fluxes into the winter hemisphere occur primarily under strong solar wind driving, and are much more prominent in energy flux than number flux, they likely reflect increased energization in the winter ionosphere when stronger currents are being driven into the ionosphere from the magnetosphere. Equinoctial behavior tends to lie between the summer and winter hemisphere values, but typically closer to the latter. As a result, nightside electron energy flux summed over the hemispheres is higher around equinox, simply because there is no summer hemisphere.
The Uncertain Legal Basis for the New Kinship

This article addresses the legal regime that affects donor-conceived family communities. It shows how these new relationships both reinforce and complicate the social, cultural, and economic meanings of family, where the law fits into all of these relationships, and why—based on the strong interests and emotional connections between members of these new communities—we might consider broader legal protections. It provides a typology of legal approaches to these new familial relationships created through donor conception.
Wide range dielectric spectroscopy on glass-forming materials: An experimental overview

Dielectric spectroscopy is one of the most commonly used techniques for the investigation of the dynamic response of glass-forming materials. The tremendous slow-down of the particle motions when approaching the glass transition and especially the fast processes in glass-forming materials, which have come into the focus of scientific interest recently, make the investigation in a wide frequency range highly desirable. Recently, results from broadband dielectric spectroscopy on glass-forming materials in their liquid and supercooled-liquid state, covering more than 18 decades of frequency have been reported by our group. In the present paper, we give an overview of the various experimental setups and techniques used to collect these spectra. As an example, spectra of the prototypical glass former glycerol are presented.
Detection of an Extrasolar Planet Atmosphere

We report high-precision spectrophotometric observations of four planetary transits of HD 209458, in the region of the sodium resonance doublet at 589.3 nm. We find that the photometric dimming during transit in a bandpass centered on the sodium feature is deeper by (2.32 ± 0.57) × 10-4 relative to simultaneous observations of the transit in adjacent bands. We interpret this additional dimming as absorption from sodium in the planetary atmosphere, as recently predicted from several theoretical modeling efforts. Our model for a cloudless planetary atmosphere with a solar abundance of sodium in atomic form predicts more sodium absorption than we observe. There are several possibilities that may account for this reduced amplitude, including reaction of atomic sodium into molecular gases and/or condensates, photoionization of sodium by the stellar flux, a low primordial abundance of sodium, and the presence of clouds high in the atmosphere.
El derecho romano en el código de derecho canónico de 1983

Se atribuye a Ludovicus Romanus (1409-1439) el adagio Legista sine canonibusparum valet, canonista sine legibus nihil, expresion con la que, en cortas palabras, su autor logro expresar la importante relacion que ha habido entre ambos derechos. Esta fue particularmente intensa en los siglos del derecho comun, a los que pertenece nuestro autor; y aun durante, los ochenta primeros anos de este siglo, la presencia del derecho romano era importante en el Codex Iuris Canonici de 1917. La sola sistematica del codigo piobenedictino, estructurada a partir del plan de las Instituciones de Gayo, es una prueba de ello. Asi pues, si hasta tiempos recientes, el influjo del derecho romano sobre el canonico ha sido importante, como los mismos canonistas han puesto de relieve', pretendo ver, en las paginas que siguen, si esa presencia se prolonga en el nuevo Codex Iuris canonici de 1983.
NMR‐CIDNP‐Untersuchung kurzlebiger Enole

Mit Hilfe der NMR-CIDNP-Spektroskopie wurden die Enole von Acetaldehyd, Propionaldehyd, Butyraldehyd, Isobutyraldehyd und 3-Methylbutyraldehyd in wasriger Losung untersucht.
Cyclical Risk Aversion, Precautionary Saving and Monetary Policy ✩

This paper analyzes the conduct of monetary policy in an environment in which cyclical swings in risk appetite aect households' propensity to save. It uses a New-Keynesian model featuring external habit formation to show that taking note of precautionary saving motives justi…es an accommodative policy bias in the face of persistent, adverse disturbances. Equally, policy should be more restrictive -that is 'lean against the wind'-following positive shocks. Under su¢ ciently persistent habits it is, in fact, optimal to increase interest rates following a rise
Peptide fragment coupling using a continuous-flow photochemical rearrangement of nitrones.

A general, versatile, efficient and novel approach for the synthesis of simple and complex peptide bonds via the title rearrangement is developed.
Management of prenatally diagnosed congenital diaphragmatic hernia

Congenital diaphragmatic hernia (CDH) is a congenital anomaly that presents with a broad spectrum of severity that is dependent upon components of pulmonary hypoplasia and pulmonary hypertension. While advances in neonatal care have improved the overall survival of CDH in experienced centers, mortality and morbidity remain high in a subset of CDH infants with severe CDH. Prenatal predictors have been refined for the past two decades and are the subject of another review in this issue. So far, all randomized trials comparing prenatal intervention to standard postnatal therapy have shown no benefit to prenatal intervention. Although recent non-randomized reports of success with fetoscopic endoluminal tracheal occlusion (FETO) and release are promising, prenatal therapy should not be widely adopted until a well-designed prospective randomized trial demonstrating efficacy is performed. The increased survival and subsequent morbidity of CDH survivors has resulted in the need to provide resources for the long-term follow up and support of the CDH population.
New quaternary compounds resulting from the reaction of copper and f-block metals in molten polychalcogenide salts at intermediate temperatures. Valence fluctuations in the layered CsCuCeS3

From the reaction of elemental copper and either lanthanides or actinides in molten alkali metal/polychalcogenide salts, several new quaternary phases have been discovered. Specifically, these phases are ACuM2Q6 (where A = K, M = La, Q = S; A = Cs, M = Ce, Q = S; or A = K, M = Ce, Q = Se) and ACuMQ3 (where A = Cs, M = Ce, Q = S; or A = K, M = U, Q = Se). The CsCuCe2S6 crystallizes in the orthorhombic space group Immm with a = 5.500(1) A, b = 22.45(1) A, c = 4.205(4) A. The KCuCe2Se6 is isostructural. The CsCuCeS3 crystallizes in the orthorhombic space group Cmcm with a = 4.024(2) A, b = 15.154(2) A, c = 10.353(3) A. The KCuUSe3 is isostructural. In ACuM2Q6, the lanthanides bond to a mixture of mono- and disulfides in a bicapped trigonal prismatic geometry; these polyhedra subsequently connect in two dimensions, forming layers equivalent to those seen in the ZrSe3 structure type with Cu+ atoms residing in tetrahedral sites within the layers and alkali cations in the interlayer gallery. The compounds of the...
Failure diagnosis using discrete-event models

Detection and isolation of failures in large, complex systems is a crucial and challenging task. The increasingly stringent requirements on performance and reliability of complex technological systems have necessitated the development of sophisticated and systematic methods for the timely and accurate diagnosis of system failures. We propose a discrete-event systems (DES) approach to the failure diagnosis problem. This approach is applicable to systems that fall naturally in the class of DES; moreover, for the purpose of diagnosis, continuous-variable dynamic systems can often be viewed as DES at a higher level of abstraction. We present a methodology for modeling physical systems in a DES framework and illustrate this method with examples. We discuss the notion of diagnosability, the construction procedure of the diagnoser, and necessary and sufficient conditions for diagnosability. Finally, we illustrate our approach using realistic models of two different heating, ventilation, and air conditioning (HVAC) systems, one diagnosable and the other not diagnosable. While the modeling methodology presented here has been developed for the purpose of failure diagnosis, its scope is not restricted to this problem; it can also be used to develop DES models for other purposes such as control.
Stereoselective Olefin Isomerization Leading to Asymmetric Quaternary Carbon Construction

Chemo- and stereoselective Ir(I)-catalyzed isomerization of 1,1-disubstituted and trisubstituted allylic ethers and in situ [3,3] sigmatropic rearrangement of the resulting allyl vinyl ethers provide for the highly stereoselective construction of quaternary carbon stereocenters. The olefin isomerization−Claisen rearrangement (ICR) sequence allows adjacent quaternary−tertiary stereocenter relationships to be established with excellent diastereoselection. Several complementary strategies for enantioselective quaternary carbon synthesis derive directly from the ICR reaction design.
Sorting n numbers on n × n reconfigurable meshes with buses

Abstract We show how column sort and rotate sort can be implemented on the different reconfigurable mesh with buses (RMB) architectures that have been proposed in the literature. On all of these proposed RMB architectures, we are able to sort n numbers on an n × n configuration in O (1) time. For the PARBUS RMB architecture, our column sort and rotate sort implementations are simpler than the O (1) sorting algorithms developed in Jang and Prasanna ( International Parallel Processing Symposium , 1992) and Lin et al . ( Proceedings of Ninth European Workshop on Parallel Computing , 1992). Furthermore, our sorting algorithms use fewer bus broadcasts. For the RMESH RMB architecture, our algorithms are the first to sort n numbers on an n × n configuration in O (1) time. We also observe that rotate sort can be implemented on N × N × ··· × N ( k + 1)-dimensional RMB architectures to sort N k elements in O (1) time.
Extracting sequence features to predict protein–DNA interactions: a comparative study

Predicting how and where proteins, especially transcription factors (TFs), interact with DNA is an important problem in biology. We present here a systematic study of predictive modeling approaches to the TF–DNA binding problem, which have been frequently shown to be more efficient than those methods only based on position-specific weight matrices (PWMs). In these approaches, a statistical relationship between genomic sequences and gene expression or ChIP-binding intensities is inferred through a regression framework; and influential sequence features are identified by variable selection. We examine a few state-of-the-art learning methods including stepwise linear regression, multivariate adaptive regression splines, neural networks, support vector machines, boosting and Bayesian additive regression trees (BART). These methods are applied to both simulated datasets and two whole-genome ChIP-chip datasets on the TFs Oct4 and Sox2, respectively, in human embryonic stem cells. We find that, with proper learning methods, predictive modeling approaches can significantly improve the predictive power and identify more biologically interesting features, such as TF–TF interactions, than the PWM approach. In particular, BART and boosting show the best and the most robust overall performance among all the methods.
A Visible Polygon Reconstruction Algorithm

An algorithm for determining visible lines or visible surfaces in polygonal form, at object resolution, is presented. The original scene must consist of non-intersecting planar polygons. The procedure relies on image coherence, since the sampling is dependent on the complexity of the image. The reconstruction method is based on an elaborate data structure, which allows the polygonal output to be easily obtained. The polygonal output is useful for smooth shaded or textured images, as well as the for creation of shadows.
Continuity of bargaining solutions

Upper semicontinuous solutions of the bargaining problem are studied and also lower semicontinuous weak solutions of that problem are considered. Though mainly compact bargaining pairs are investigated, extensions to non-compact bargaining pairs are indicated. The continuity properties of some well known bargaining solutions are discussed.
The Casson-Walker-Lescop Invariant and Link Invariants

Formulas previously presented for the Casson–Walker invariant are generalized to Lescop's extension. These formulas in terms of linking numbers and surgery coefficients compute the change in Lescop's invariant under crossing changes in a framed link presenting a 3-manifold. This leads us to revisit an old formula for a coefficient of the Conway polynomial. Finally we compute Lescop's invariant of several lens spaces.
Measuring Shared Information and Coordinated Activity in Neuronal Networks

Most nervous systems encode information about stimuli in the responding activity of large neuronal networks. This activity often manifests itself as dynamically coordinated sequences of action potentials. Since multiple electrode recordings are now a standard tool in neuroscience research, it is important to have a measure of such network-wide behavioral coordination and information sharing, applicable to multiple neural spike train data. We propose a new statistic, informational coherence, which measures how much better one unit can be predicted by knowing the dynamical state of another. We argue informational coherence is a measure of association and shared information which is superior to traditional pairwise measures of synchronization and correlation. To find the dynamical states, we use a recently-introduced algorithm which reconstructs effective state spaces from stochastic time series. We then extend the pairwise measure to a multivariate analysis of the network by estimating the network multi-information. We illustrate our method by testing it on a detailed model of the transition from gamma to beta rhythms.
Generational perspective of higher education online student learning styles

A study was conducted of students participating in on-line academic courses in institutions of higher education to ascertain if there was a generational influence on learning styles. The specific research question was: What, if any, relationships exist among learning styles, generational groups, and satisfaction with online learning? Inferential and descriptive statistics were used to determine there was a statistically significant differences between Baby Boomers and the Millennial Generation as well as Generation X. Baby Boomers were found to have significantly lower scores on this subscale as compared with both the Millennial Generation and Generation X. In addition, the Millennial Generation reported lower scores on overall satisfaction survey components as compared with both Generation Xers and Baby Boomers.
A Software-Optimized Encryption Algorithm

We describe the software-efficient encryption algorithm SEAL 3.0. Computational cost on a modern 32-bit processor is about 4 clock cycles per byte of text. The cipher is a pseudorandom function family: under control of a key (first preprocessed into an internal table) it stretches a 32-bit position index into a long, pseudorandom string. This string can be used as the keystream of a Vernam cipher.
Inferring Graphs from Cascades: A Sparse Recovery Framework

In the Graph Inference problem, one seeks to recover the edges of an unknown graph from the observations of cascades propagating over this graph. We approach this problem from the sparse recovery perspective. We introduce a general model of cascades, including the voter model and the independent cascade model, for which we provide the first algorithm which recovers the graph's edges with high probability and O(s log m) measurements where s is the maximum degree of the graph and $m$ is the number of nodes. Furthermore, we show that our algorithm also recovers the edge weights (the parameters of the diffusion process) and is robust in the context of approximate sparsity. Finally we validate our approach empirically on synthetic graphs.
Ligand-unsupported Au(I) chains with short Au(I)...Au(I) contacts.

A new series of solids with ligand-unsupported Au(I) chains with short Au⋯Au contacts were synthesized; as Ag compounds with the same structure are known, the new phases now allow unbiased comparison of Ag⋯Ag and Au⋯Au metallophilic bonds not supported by bridging ligands, which shows the latter to be consistently shorter by 0.03–0.04 A.
A single-instance incremental SAT formulation of proof- and counterexample-based abstraction

This paper presents an efficient, combined formulation of two widely used abstraction methods for bit-level verification: counterexample-based abstraction (CBA) and proof-based abstraction (PBA). Unlike previous work, this new method is formulated as a single, incremental SAT-problem, interleaving CBA and PBA to develop the abstraction in a bottom-up fashion. It is argued that the new method is simpler conceptually and implementation-wise than previous approaches. As an added bonus, proof-logging is not required for the PBA part, which allows for a wider set of SAT-solvers to be used.
Catalytic Enantioselective Halolactonization of Enynes and Alkenes

New organocatalysts have been developed for the enantioselective halolactonization of (Z)-1,3-enynes and 1,1-disubstituted alkenes. In the case of 1,3-enynes, the carboxylate nucleophile and halogen electrophile were added to the conjugated π-system from the same face. Up to 99% ee was achieved for the 1,4-syn-bromolactonization of conjugated (Z)-1,3-enynes. Based on the results from the enyne halolactonization, a second generation of catalysts was designed for simple olefins. Up to 91% ee was observed for chlorolactonization of 1,1-disubstituted alkenes. The catalysts developed for the enantioselective halolactonization of both enynes and alkenes are composed of a cinchona alkaloid skeleton tethered to a urea group.
Musashi proteins are post-transcriptional regulators of the epithelial-luminal cell state

The conserved Musashi (Msi) family of RNA binding proteins are expressed in stem/progenitor and cancer cells, but generally absent from differentiated cells, consistent with a role in cell state regulation. We found that Msi genes are rarely mutated but frequently overexpressed in human cancers and are associated with an epithelial-luminal cell state. Using ribosome profiling and RNA-seq analysis, we found that Msi proteins regulate translation of genes implicated in epithelial cell biology and epithelial-to-mesenchymal transition (EMT), and promote an epithelial splicing pattern. Overexpression of Msi proteins inhibited the translation of Jagged1, a factor required for EMT, and repressed EMT in cell culture and in mammary gland in vivo. Knockdown of Msis in epithelial cancer cells promoted loss of epithelial identity. Our results show that mammalian Msi proteins contribute to an epithelial gene expression program in neural and mammary cell types. DOI: http://dx.doi.org/10.7554/eLife.03915.001
Sestrin 3 Protein Enhances Hepatic Insulin Sensitivity by Direct Activation of the mTORC2-Akt Signaling

Sestrin proteins have been implicated in multiple biological processes including resistance to oxidative and genotoxic stresses, protection against aging-related pathologies, and promotion of metabolic homeostasis; however, the underlying mechanisms are incompletely understood. Some evidence suggests that sestrins may inhibit mTORC1 (mechanistic target of rapamycin complex 1) through inhibition of RagA/B GTPases or activation of AMPK; however, whether sestrins are also involved in mTORC2 regulation and function is unclear. To investigate the functions and mechanisms of Sestrin 3 (Sesn3), we generated Sesn3 liver-specific transgenic and knockout mice. Our data show that Sesn3 liver-specific knockout mice exhibit insulin resistance and glucose intolerance, and Sesn3 transgenic mice were protected against insulin resistance induced by a high-fat diet. Using AMPK liver-specific knockout mice, we demonstrate that the Sesn3 insulin-sensitizing effect is largely independent of AMPK. Biochemical analysis reveals that Sesn3 interacts with and activates mTORC2 and subsequently stimulates Akt phosphorylation at Ser473. These findings suggest that Sesn3 can activate Akt via mTORC2 to regulate hepatic insulin sensitivity and glucose metabolism.
Efficient retina formation requires suppression of both Activin and BMP signaling pathways in pluripotent cells

Retina formation requires the correct spatiotemporal patterning of key regulatory factors. While it is known that repression of several signaling pathways lead to specification of retinal fates, addition of only Noggin, a known BMP antagonist, can convert pluripotent Xenopus laevis animal cap cells to functional retinal cells. The aim of this study is to determine the intracellular molecular events that occur during this conversion. Surprisingly, blocking BMP signaling alone failed to mimic Noggin treatment. Overexpressing Noggin in pluripotent cells resulted in a concentration-dependent suppression of both Smad1 and Smad2 phosphorylation, which act downstream of BMP and Activin signaling, respectively. This caused a decrease in downstream targets: endothelial marker, xk81, and mesodermal marker, xbra. We treated pluripotent cells with dominant-negative receptors or the chemical inhibitors, dorsomorphin and SB431542, which each target either the BMP or Activin signaling pathway. We determined the effect of these treatments on retina formation using the Animal Cap Transplant (ACT) assay; in which treated pluripotent cells were transplanted into the eye field of host embryos. We found that inhibition of Activin signaling, in the presence of BMP signaling inhibition, promotes efficient retinal specification in Xenopus tissue, mimicking the affect of adding Noggin alone. In whole embryos, we found that the eye field marker, rax, expanded when adding both dominant-negative Smad1 and Smad2, as did treating the cells with both dorsomorphin and SB431542. Future studies could translate these findings to a mammalian culture assay, in order to more efficiently produce retinal cells in culture.
Probability distribution function of the upper equatorial Pacific current speeds

[1] The probability distribution function (PDF) of the upper (0–50 m) tropical Pacific current speeds (w), constructed from hourly ADCP data (1990–2007) at six stations for the Tropical Atmosphere Ocean project, satisfies the two-parameter Weibull distribution reasonably well with different characteristics between El Nino and La Nina events: In the western Pacific, the PDF of w has a larger peakedness during the La Nina events than during the El Nino events; and vice versa in the eastern Pacific. However, the PDF of w for the lower layer (100–200 m) does not fit the Weibull distribution so well as the upper layer. This is due to the different stochastic differential equations between upper and lower layers in the tropical Pacific. For the upper layer, the stochastic differential equations, established on the base of the Ekman dynamics, have analytical solution, i.e., the Rayleigh distribution (simplest form of the Weibull distribution), for constant eddy viscosity K. Knowledge on PDF of w during the El Nino and La Nina events will improve the ensemble horizontal flux calculation, which contributes to the climate studies.
Computational and experimental study of stall propagation in axial compressors

We present a numerical and experimental study of stall propagation in axial compressors. In the numerical study, the compressor blades are represented as an isolated linear cascade of airfoils, and the stall propagation is simulated using a vortex tracking method.
Sources of funds and quality effects in higher education

Abstract Economists have suggested that the quality of higher education is not independent of the sources of funds used to fund that education. This paper examines the relationship between student measures of teaching quality and institutional revenue sources. The results indicate that a greater reliance on private subsides is associated with higher measures of teacher quality. A greater reliance on public subsidies, however, leads to lower teacher quality ratings. The importance of these results for shaping public policy decisions is also discussed.
A new synthetic approach to the C-D ring portion of streptonigrin analogues

Development of an efficient synthesis of the C-D ring portion of streptonigrin is a key operation in the synthesis of this antibiotic and its analogues. A new method for the synthesis of 3-cyano-5,6-dimethyl-4-(3,4,5-trimethoxyphenyl)-2-pyridone (14), a compound having the requisite functionality for conversion into a streptonigrin analogue, has been established. It involves treatment of 3,4,5-trimethoxybenzonitrile with ethylmagnesium bromide and malononitrile to give propylenemalononitrile derivative 7, which is condensed with trimethyl orthoacetate to give a mixture of 9 and pyridine derivative 12. Demethylation of 12 then affords 14. The overall yield for this route was 50%, allowing for conversion of 9 to 12.
Mechanically adjustable and electrically gated single-molecule transistors.

We demonstrate a device geometry for single-molecule electronics experiments that combines both the ability to adjust the spacing between the electrodes mechanically and the ability to shift the energy levels in the molecule using a gate electrode. With the independent in-situ variations of molecular properties provided by these two experimental “knobs”, we are able to achieve a much more detailed characterization of electron transport through the molecule than is possible with either technique separately. We illustrate the performance of the device using C 60 molecules.
Unmixed local rings with minimal Hilbert-Kunz multiplicity are regular

We give a new and simple proof that unmixed local rings having Hilbert-Kunz multiplicity equal to 1 must be regular.
Magnetic Susceptibility of the Balian-Werthamer Phase of 3He in Aerogel

The equilibrium superfluid phase of 3He impregnated into high-porosity (98%) silica aerogels appears to be a non-equal-spin-pairing state in zero field at all pressures, which is generally assumed to be the Balian–Werthamer (BW) phase modified by the depairing effects of the aerogel structure. The nuclear magnetic susceptibility played a key role in identifying the B-phase of pure 3He with the BW state. We report theoretical calculations of the nuclear magnetic susceptibility for the BW model of superfluid 3He in aerogel within the framework of the Fermi-liquid theory of superfluid 3He. Scattering of quasiparticles by the aerogel, in addition to Fermi-liquid exchange corrections, leads to substantial changes in the susceptibility of the BW phase. The increase in the magnetic susceptibility of 3He-aerogel compared to pure3He-B is related to the polarizability of the gapless excitations and the impurity-induced local field. The limited data that is available is in rough agreement with theoretical predictions. Future measurements could prove important for a more definitive identification of the ordered phase, as well as for refining the theoretical model for the effects of disorder and scattering on the properties of superfluid 3He.
Multi-Factor Bottom-Up Model for Pricing Credit Derivatives

In this note we continue the study of the stress event model, a simple and intuitive dynamic model for credit risky portfolios, proposed by Duffie and Singleton (1999). The model is a bottom-up version of the multi-factor portfolio credit model proposed by Longstaff and Rajan (2008). By a novel identification of independence conditions, we are able to decompose the loss distribution into a series expansion which not only provides a clear picture of the characteristics of the loss distribution but also suggests a fast and accurate approximation for it. Our approach has three important features: (i) it is able to match the standard CDS index tranche prices and the underlying CDS spreads, (ii) the computational speed of the loss distribution is very fast, comparable to that of the Gaussian copula, (iii) the computational cost for additional factors is mild, allowing for more ﬂexibility for calibrations and opening the possibility of studying multi-factor default dependence of a portfolio via a bottom-up approach. We demonstrate the tractability and efficiency of our approach by calibrating it to investment grade CDS index tranches.
The network centric test system

Network topology is an important choice for the test system designer. There are several to choose from and each has benefits. A comparison of topologies is made based on the benefits and drawbacks for various usage situations. Some of the topologies of interest are: placing the instrumentation and the controller on the corporate intranet; using switching hubs for traffic isolation; using a second LAN connection in the test system controller as a private network for instrumentation; placing a router between the intranet and the test system controller; and widely distributing test assets. Test asset visibility to the rest of the network has both security and test integrity implications. Trading off the benefits of ready access and observation (which promotes collaboration) against system visibility needs to be carefully examined. Several use cases will be presented for examination: simply connected user; semi-automated test; fully automated test; and remote collaboration for system problem-solving.
A Multilevel Examination of the Drivers of Firm Multinationality A Meta-Analysis

Significant research has been devoted to studying the factors that affect firm multinationality. In this study, the authors organize the vast multinationality literature by levels of analysis using a multilevel framework based on the interaction paradigm and conduct a meta-analysis that aggregates the empirical findings from 154 independent samples reported in 145 studies. The cumulative evidence provides strong support for the upper echelons theory that emphasizes the central importance of executives’ characteristics as major determinants of firm multinationality. Moreover, the results indicate that the accumulation of the international experience embedded in human and relational capital is the most significant firm-level factor that affects firm multinationality. The meta-analytic results also reveal that the measurement and sample characteristics of original studies explain the inconsistent findings pertaining to the effects of firm size, firm age, and top management team size on multinationality. On t...
The effect of topography on radar scattering from vegetated areas

The ways in which radar scattering from vegetated areas is affected by the topography of the surface underneath the vegetation are discussed. It is shown, using a discrete scatterer model, that the dominant scattering mechanism may change drastically when the ground surface is tilted relative to the horizontal. For a horizontal ground surface, for example, the total scattering may be dominated by scattering off the tree trunks, followed by a reflection off the ground surface. For a relatively small tilt in the ground surface, the ground-trunk interaction term may be replaced by scattering from the branches alone as the dominant scattering mechanism. The effect of the topography is more pronounced for scattering by longer wavelengths, and the implications on algorithms designed to infer forest woody biomass and soil and vegetation moisture using polarimetric SAR data are discussed. The effect of the topography on the scattering behavior from forested areas is illustrated with images acquired by the NASA/JPL three-frequency polarimetric SAR over the Black Forest in Germany. >
The notion of a rational convex program, and an algorithm for the arrow-debreu Nash bargaining game

We introduce the notion of a rational convex program (RCP) and we classify the known RCPs into two classes: quadratic and logarithmic. The importance of rationality is that it opens up the possibility of computing an optimal solution to the program via an algorithm that is either combinatorial or uses an LP-oracle. Next, we define a new Nash bargaining game, called ADNB, which is derived from the linear case of the Arrow-Debreu market model. We show that the convex program for ADNB is a logarithmic RCP, but unlike other known members of this class, it is nontotal.Our main result is a combinatorial, polynomial-time algorithm for ADNB. It turns out that the reason for infeasibility of logarithmic RCPs is quite different from that for LPs and quadratic RCPs. We believe that our ideas for surmounting the new difficulties will be useful for dealing with other nontotal RCPs as well. We give an application of our combinatorial algorithm for ADNB to an important “fair” throughput allocation problem on a wireless channel. Finally, we present a number of interesting questions that the new notion of RCP raises.
Tuning fulleride electronic structure and molecular ordering via variable layer index.

C60 fullerides are uniquely flexible molecular materials that exhibit a rich variety of behaviour1, including superconductivity and magnetism in bulk compounds2,3, novel electronic and orientational phases in thin films4,5,6,7,8,9,10 and quantum transport in a single-C60 transistor11. The complexity of fulleride properties stems from the existence of many competing interactions, such as electron–electron correlations, electron–vibration coupling and intermolecular hopping. The exact role of each interaction is controversial owing to the difficulty of experimentally isolating the effects of a single interaction in the intricate fulleride materials. Here, we report a unique level of control of the material properties of KxC60 ultrathin films through well-controlled atomic layer indexing and accurate doping concentrations. Using scanning tunnelling microscope techniques, we observe a series of electronic and structural phase transitions as the fullerides evolve from two-dimensional monolayers to quasi-three-dimensional multilayers in the early stages of layer-by-layer growth. These results demonstrate the systematic evolution of fulleride electronic structure and molecular ordering with variable KxC60 film layer index, and provide essential information for the development of new molecular structures and devices.
Radar hydrology: rainfall estimation.

Radar observations of rainfall and their use in hydrologic research provide the focus for the paper. Radar-rainfall products are crucial for input to runoff and flood prediction models, validation of satellite remote sensing algorithms, and for statistical characterization of extreme rainfall frequency. In this context we discuss the issues of radar-rainfall product development, and the theoretical and practical requirements of validating radar-rainfall maps and new radar technologies. We discuss a framework for reflectivity based rainfall estimation, including estimation of uncertainty of radar-rainfall estimates. Validation of radar-rainfall products is a major challenge for broad utilization of these products in hydrologic applications. In the discussion of radar-rainfall prediction we focus on orographically induced extreme rainfall and flooding, discuss the issues of detection, statistical sample size, and scale effects. We conclude the paper with a set of recommendations for research priorities and experimental requirements to address them.
Selected Results in Additive Combinatorics: An Exposition

We give a self-contained exposition of selected results in additive combinatorics over the group GF(2) n = {0,1} n . In particular, we prove the celebrated theorems known as the Balog-Szemeredi-Gowers theorem (’94 and ’98) and the Freiman-Ruzsa theorem (’73 and ’99), leading to the remarkable result by Samorodnitsky (’07) that linear transformations are efficiently testable. No new result is proved here. However, we strip down the available proofs to the bare minimum needed to derive the efficient testability oflinear transformations over {0,1} n , thus hoping to provide a computer science-friendly introduction to the marvelous field of additive combinatorics.
Expanding Credit Access: Using Randomized Supply Decisions to Estimate the Impacts

Expanding access to commercial credit is a key ingredient of financial development strategies. There is less consensus on whether expanding access to consumer credit helps borrowers, particularly when loans are extended at high interest rates. Popular skepticism about "unproductive," "usurious" lending is fueled by research highlighting behavioral biases that may induce overborrowing. We estimate the impacts of expanding access to consumer credit at a 200% annual percentage rate (APR) using a field experiment and follow-up data collection. The randomly assigned marginal loans produced significant net benefits for borrowers across a wide range of outcomes. There is also some evidence that the loans were profitable. The Author 2009. Published by Oxford University Press on behalf of The Society for Financial Studies. All rights reserved. For Permissions, please e-mail: journals.permissions@oxfordjournals.org, Oxford University Press.
A new approach toward transition state spectroscopy

Chirped-Pulse millimetre-Wave (CPmmW) rotational spectroscopy provides a new class of information about photolysis transition state(s). Measured intensities in rotational spectra determine species-isomer-vibrational populations, provided that the rotational populations can be thermalized. The formation and detection of S0 vinylidene is discussed in the limits of low and high initial rotational excitation. CPmmW spectra of 193 nm photolysis of vinyl cyanide (acrylonitrile) contain J = 0–1 transitions in more than 20 vibrational levels of HCN and HNC, but no transitions in vinylidene or highly excited local-bender vibrational levels of acetylene. Reasons for the non-observation of the vinylidene co-product of HCN are discussed.