cssi/SciSciGPT-SciSciNet huggingface dataset:
TYPE IIB SUPERSTRINGS, BPS MONOPOLES, AND THREE-DIMENSIONAL GAUGE DYNAMICS

We propose an explanation via string theory of the correspondence between the Coulomb branch of certain three-dimensional supersymmetric gauge theories and certain moduli spaces of magnetic monopoles. The same construction also gives an explanation, via SL(2, Z) duality of Type IIB superstrings, of the recently discovered “mirror symmetry” in three dimensions. New phase transitions in three dimensions as well as new infrared fixed points and even new coupling constants not present in the known Lagrangians are predicted from the string theory construction. An important role in the construction is played by a novel aspect of brane dynamics in which a third brane is created when two branes cross.
SIRT1 Suppresses the Epithelial-to-Mesenchymal Transition in Cancer Metastasis and Organ Fibrosis

The epithelial-to-mesenchymal transition (EMT) is important for the development of cancer metastases and organ fibrosis, conditions prevalent in aging. Because sirtuins affect the pathology of aging, we tested the effect of SirT1 on EMT. Reduced SIRT1 levels in HMLER breast cancer cells led to increased metastases in nude mice, and the loss of SIRT1 in kidney tubular epithelial cells exacerbated injury-induced kidney fibrosis. SIRT1 reduces EMT in cancer and fibrosis by deacetylating Smad4 and repressing the effect of TGF-β signaling on MMP7, a Smad4 target gene. Consequently, less E-cadherin is cleaved from the cell surface and β-catenin remains bound to E-cadherin at the cell-cell junctions. Our findings suggest that the SIRT1/Smad4/β-catenin axis may be a target for diseases driven by EMT.
Bulk separation of multicomponent gas mixtures by pressure swing adsorption: Pore/surface diffusion and equilibrium models

A theoretical and experimental study is performed for the bulk separation of a ternary mixture by pressure swing adsorption. Three concentrated products can be obtained by cycling the pressure in the adsorber. Three models are formulated for the cyclic process: equilibrium, Knudsen diffusion, and Knudsen plus surface diffusion. The latter model provides the best results when compared with the experimental data, due to the important contribution of surface flux to the total flux in the sorbent pores.
Relative Equilibria of the (1+N)-Vortex Problem

We examine existence and stability of relative equilibria of the n-vortex problem specialized to the case where N vortices have small and equal circulation and one vortex has large circulation. As the small circulation tends to zero, the weak vortices tend to a circle centered on the strong vortex. A special potential function of this limiting problem can be used to characterize orbits and stability. Whenever a critical point of this function is nondegenerate, we prove that the orbit can be continued via the Implicit Function Theorem, and its linear stability is determined by the eigenvalues of the Hessian matrix of the potential. For N≥3 there are at least three distinct families of critical points associated to the limiting problem. Assuming nondegeneracy, one of these families continues to a linearly stable class of relative equilibria with small and large circulation of the same sign. This class becomes unstable as the small circulation passes through zero and changes sign. Another family of critical points which is always nondegenerate continues to a configuration with small vortices arranged in an N-gon about the strong central vortex. This class of relative equilibria is linearly unstable regardless of the sign of the small circulation when N≥4. Numerical results suggest that the third family of critical points of the limiting problem also continues to a linearly unstable class of solutions of the full problem independent of the sign of the small circulation. Thus there is evidence that linearly stable relative equilibria exist when the large and small circulation strengths are of the same sign, but that no such solutions exist when they have opposite signs. The results of this paper are in contrast to those of the analogous celestial mechanics problem, for which the N-gon is the only relative equilibrium for N sufficiently large, and is linearly stable if and only if N≥7.
Unicast-based multicast communication in wormhole-routed networks

Multicast communication, in which the same message is delivered from a source node to an arbitrary number of destination nodes, is being increasingly demanded in parallel computing. System supported multicast services can potentially offer improved performance, increased functionality, and simplified programming, and may in turn be used to support various higher-level operations for data movement and global process control. This paper presents efficient algorithms to implement multicast communication in wormhole-routed direct networks, in the absence of hardware multicast support, by exploiting the properties of the switching technology. Minimum-time multicast algorithms are presented for n-dimensional meshes and hypercubes that use deterministic, dimension-ordered routing of unicast messages. Both algorithms can deliver a multicast message to m-1 destinations in [log/sub 2/ m] message passing steps, while avoiding contention among the constituent unicast messages. Performance results of implementations on a 64-node nCUBE-2 hypercube and a 168-node Symult 2010 2-D mesh are given. >
Analysis of Solid–Liquid Phase Change Under Pulsed Heating

Solid/liquid phase change occurring in a rectangular container with and without metal foams subjected to periodic pulsed heating is investigated. Natural convection in the melt is considered. Volume-averaged mass and momentum equations are employed, with the Brinkman-Forchheimer extension to Darcy's law used to model the porous resistance. A local thermal nonequilibrium model, assuming equilibrium melting at the pore scale, is employed for energy transport through the metal foams and the interstitial phase change material (PCM). Separate volume-averaged energy equations for the foam and the PCM are written and are closed using a heat transfer coefficient. The enthalpy method is employed to account for phase change. The governing equations for the PCM without foam are derived from the porous medium equations. The governing equations are solved implicitly using a finite volume method on a fixed grid. The coupled effect of pulse width and natural convection in the melt is found to have a profound effect on the overall melting behavior. The influence of pulse width, Stefan number, and Rayleigh number on the temporal evolution of the melt front location and the melting rate for both the cases with and without metal foams is investigated.
An examination of executive stock option repricing

Abstract Comparing a sample of firms that reprice executive stock options in 1998 to a control sample of firms with out-of-the-money options in 1998 that do not reprice, we find that the likelihood of repricing increases for young, high technology firms and firms whose options are more out-of-the-money. Further, we find that firms reprice in response to poor firm-specific, not poor industry, performance. However, we find no evidence that repricing is related to agency problems. Our results are consistent with firms repricing options to restore incentive effects and to deter managers in competitive labor markets from going to work for other firms.
Pd(OAc)2/2-aryl-2-oxazolines catalyzed Suzuki coupling reactions of aryl bromides and arylboronic acids

Abstract A series of 2-aryl-2-oxazolines were prepared and examined as ligands for the Suzuki coupling reaction of aryl bromides and arylboronic acids. 2,2′-(1,3-Phenylene)bisoxazoline/Pd(OAc)2 was found to be an efficient catalyst for a variety of substrates to afford the coupling products in good to excellent yields.
Competitive equilibria of economies with a continuum of consumers and aggregate shocks

This paper studies competitive equilibria of a production economy with aggregate productivity shocks. There is a continuum of consumers who face borrowing constraints and individual labor endowment shocks. The dynamic economy is described in terms of sequences of aggregate distributions. The existence of competitive equilibrium is proven and a recursive characterization is established. In particular, it is shown that for any competitive equilibrium, there is a payoff equivalent competitive equilibrium that is generated by a suitably defined recursive equilibrium.
"Synthetic Metals": A Novel Role for Organic Polymers (Nobel Lecture).

Since the initial discovery in 1977, that polyacetylene (CH)(x), now commonly known as the prototype conducting polymer, could be p- or n-doped either chemically or electrochemically to the metallic state, the development of the field of conducting polymers has continued to accelerate at an unexpectedly rapid rate and a variety of other conducting polymers and their derivatives have been discovered. Other types of doping are also possible, such as "photo-doping" and "charge-injection doping" in which no counter dopant ion is involved. One exciting challenge is the development of low-cost disposable plastic/paper electronic devices. Conventional inorganic conductors, such as metals, and semiconductors, such as silicon, commonly require multiple etching and lithographic steps in fabricating them for use in electronic devices. The number of processing and etching steps involved limits the minimum price. On the other hand, conducting polymers combine many advantages of plastics, for example, flexibility and processing from solution, with the additional advantage of conductivity in the metallic or semiconducting regimes; however, the lack of simple methods to obtain inexpensive conductive polymer shapes/patterns limit many applications. Herein is described a novel, simple, and cheap method to prepare patterns of conducting polymers by a process which we term, "Line Patterning".
Library Change as a Branding Opportunity: Connect, Reflect, Research, Discover

Author(s): Stimson, Nancy F. | Abstract: In 2004, during a major renovation and addition project, the University of California-San Diego (UCSD) Biomedical Library temporarily moved from its permanent location near the medical and pharmacy schools to the main library. The renovation and relocation inspired library administrators and staff to develop and articulate a brand for the library. This article describes the step-by-step process that the library used to create and utilize a brand.
Collective Memory: The Two Cultures

What is collective about collective memory? Two different concepts of collective memory compete—one refers to the aggregation of socially framed individual memories and one refers to collective phenomena sui generis—though the difference is rarely articulated in the literature. This article theorizes the differences and relations between individualist and collectivist understandings of collective memory. The former are open to psychological considerations, including neurological and cognitive factors, but neglect technologies of memory other than the brain and the ways in which cognitive and even neurological patterns are constituted in part by genuinely social processes. The latter emphasize the social and cultural patternings of public and personal memory, but neglect the ways in which those processes are constituted in part by psychological dynamics. This article advocates, through the example of traumatic events, a strategy of multidimensional rapprochement between individualist and collectivist appro...
ICT and productivity in Europe and the United States. Where do the differences come from

The surge in labor productivity growth in the United States in the late 1990s has prompted much speculation about the capacity of Information and Communication Technologies (ICT) to structurally increase growth. The simultaneous slowdown in productivity growth in the EU suggests the European countries are falling behind. In this paper we will analyze labor productivity growth in 51 industries in Europe and the United States. Using shift-share techniques we identify the industries in which the U.S. has gained a lead and the underlying reasons for this. The results show that the U.S. has grown faster than the EU because of a larger ICT producing sector and faster growth in services industries that make intensive use of ICT. Lagging growth in Europe is concentrated in wholesale and retail trade and the securities industry.
Tests for Skewness, Kurtosis, and Normality for Time Series Data

We present the sampling distributions for the coefficient of skewness, kurtosis, and a joint test of normality for time series observations. We show that when the data are serially correlated, consistent estimates of three-dimensional long-run covariance matrices are needed for testing symmetry or kurtosis. These tests can be used to make inference about any conjectured coefficients of skewness and kurtosis. In the special case of normality, a joint test for the skewness coefficient of 0 and a kurtosis coefficient of 3 can be obtained on construction of a four-dimensional long-run covariance matrix. The tests are developed for demeaned data, but the statistics have the same limiting distributions when applied to regression residuals. Monte Carlo simulations show that the test statistics for symmetry and normality have good finite-sample size and power. However, size distortions render testing for kurtosis almost meaningless except for distributions with thin tails, such as the normal distribution. Combini...
Degrees of Freedom for the MIMO Interference Channel

In this correspondence, we show that the exact number of spatial degrees of freedom (DOF) for a two user nondegenerate (full rank channel matrices) multiple-input-multiple-output (MIMO) Gaussian interference channel with M1, M2 antennas at transmitters 1, 2 and N1, N2 antennas at the corresponding receivers, and perfect channel knowledge at all transmitters and receivers, is min{M1 + M2, N1 + M2, max(M1, N2), max(M2, N1)}. A constructive achievability proof shows that zero forcing is sufficient to achieve all the available DOF on the two user MIMO interference channel. We also show through an example of a share-and-transmit scheme how the gains of transmitter cooperation may be entirely offset by the cost of enabling that cooperation so that the available DOF are not increased.
From Mead to a Structural Symbolic Interactionism and Beyond

This review discusses the continuing value of and problems in G.H. Mead's contributions to sociology from the standpoint of the contemporary discipline. It argues that the value is considerable and the problems largely avoidable with modifications to Mead's framework; it also offers necessary modifications via structural symbolic interactionism. Permitting the development of testable theories such as identity theory is a major criterion in evaluating a frame, and capacity to bridge to other frames and theories inside and outside sociology is another. The review examines bridges from the structural symbolic interactionist frame and identity theory to other symbolic interactionist theories, to other social psychological frames and theories in sociology, to cognitive social psychology, and to structural sociology.
Bulk gold (non-nanogold) catalysis of aerobic oxidations of amines, isocyanides, carbon monoxide, and carbene precursors

Oxidative reactions that are catalysed by bulk gold consisting of ∼50000 nm gold powder particles or gold (∼50 nm) supported on Al2O3 are reviewed. Using O2 as the oxidizing agent, bulk gold catalyzes the following types of reactions in organic solvents at 45–90 °C: (1) the conversion of amines to imines [(RCH2)2NH → RCH2NCHR], (2) the oxidation of benzyl alcohol to benzaldehyde, (3) the reaction of isocyanides with primary amines to give carbodiimides [CN–R + H2N–R′ → R′–NCN–R] and with secondary amines to give ureas , (4) the reactions of CO with primary amines to give ureas [CO + H2N–R → OC(NHR)2], and (5) the reactions of diazoalkanes with amines to give enamines . In some of these reactions, amine oxides (e.g., Me3N–O) may be used in place of O2. Mechanisms of these and related reactions are examined. These studies show that bulk, non-nanogold is capable of catalysing a variety of different reactions.
On Bootstrap Coverage Probability with Dependent Data

This paper establishes the optimal bootstrap block lengths for coverage probabilities when the bootstrap is applied to covariance stationary ergodic dependent data. It is shown that the block lengths that minimize the error in coverage probabilities of one- and two-sided block bootstrap confidence intervals of normalized and studentized smooth functions of sample averages are proportional to $n^{1/4}$. The minimum error rates in coverage probabilities of one- and two-sided block bootstrap confidence intervals are of order O($n^{-3/2}$) and O($n^{-5/4}$), respectively, for normalized and studentized statistics. This constitutes a refinement over the asymptotic confidence intervals.
The influence of checklists and roles on software practitioner risk perception and decision-making

This paper investigates: (1) the influence of risk checklists on software practitioner risk perception and decision-making, and (2) the influence of role (inside project manager vs. outside consultant) on software practitioner risk perception and decision-making. Evidence on these points is presented based on a role playing experiment conducted with 128 software practitioners. Results show that (1) the risk checklist helped subjects identify more risks than they would identify without the aid of a checklist, whereas (2) the role assigned to subjects did not seem to affect either their risk perception or behavior. Moreover, the use of a risk checklist shaped subjects' perceptions of which risks were salient in the scenario, whereas the number of risks identified did not affect their decision-making. Interestingly, subjects using a checklist were able to identify more seeded risks in the scenario, but they also identified more unseeded risks. Implications for research and practice are discussed.
A plan-based model for response generation in collaborative task-oriented dialogues

This paper presents a plan-based architecture for response generation in collaborative consultation dialogues, with emphasis on cases in which the system (consultant) and user (executing agent) disagree. Our work contributes to an overall system for collaborative problem-solving by providing a plan-based framework that captures the Propose-Evaluate-Modify cycle of collaboration, and by allowing the system to initiate subdialogues to negotiate proposed additions to the shared plan and to provide support for its claims. In addition, our system handles in a unified manner the negotiation of proposed domain actions, proposed problem-solving actions, and beliefs proposed by discourse actions. Furthermore, it captures cooperative responses within the collaborative framework and accounts for why questions are sometimes never answered.
Neighbors of the origin for four by three matrices

Scarf has defined a neighborhood system for families of integer programs where the right-hand side is allowed to vary. This system depends on a matrix A of constraint and objective function coefficients of the integer programs. This paper characterizes the set of neighbors of the origin when A is four by three, showing that it may be described as the set of integer vectors in a union of two-dimensional polyhedra, where the number of polyhedra is quadratic in the bit size of A.
Comparison of f-Q scaling in wineglass and radial modes in ring resonators

Low phase noise MEMS oscillators necessitate resonators with high f-Q. Resonators achieving high f-Q (mechanical frequency-quality factor product) close to the thermo-elastic damping (TED) limit have been demonstrated at expense of feed-through. Here we present a study comparing frequency scaling of quality factors of wineglass and radial modes in a ring resonator using an opto-mechanical two port transmission measurement. Higher harmonics of the wineglass mode show an increasing trend in the f-Q product, as compared to a saturation of f-Q for radial modes. The measured f-Q of 5.11×1013 Hz at 9.82GHz in air at room temperature for a wineglass mode is close to the highest measured values in silicon resonators.
Life around the scallop theorem

Locomotion on small scales is dominated by the effects of viscous forces and, as a result, is subject to strong physical and mathematical constraints. Following Purcell's statement of the scallop theorem which delimitates the types of swimmer designs which are not effective on small scales, we review the different ways the constraints of the theorem can be escaped for locomotion purposes.
Preparation and reactions of chiral propargylic amines

Abstract Exposure of chiral amino aldehydes ( 1 ) to dimethyl diazophosphonate ( 4 ) affords propargylic amines ( 2 ) of high optical purity. Chain extension of these intermediates is readily accomplished via hydrozirconation of the acetylene moiety and subsequent Ni(II) catalyzed Michael addition to a variety of Michael acceptors.
Unsteady Transonic Airfoil Computation Using Implicit Euler Scheme on Body-Fixed Grid

The unsteady Euler equations have been derived for the flow relative motion with respect to a frame of reference that is rigidly attached to the moving airfoil. The resulting equations preserve the conservation form. The grid is generated once by an elliptic solver without any need for dynamic grid computation. An implicit approximately factored finite-volume scheme has been developed and implemented through a fully vectorized computer program. The scheme is based on the spatial approximate factorization of Beam and Warming. Implicit second-order and explicit second- and fourth-order dissipations are added to the scheme. The boundary conditions are explicitly satisfied. The scheme is applied to steady and unsteady transonic rigid-airfoil flows. For forced harmonic airfoil motions, periodic solutions are achieved within the third cycle of oscillation. The results are in good agreement with the experimental data. sonic flows past a NACA 0015 airfoil at a constant pitch rate.18 The latter case is the same application considered in Ref. 16. The numerical solution has been obtained by using the flux-vector splitting and the flux-difference splitting meth- ods extended for dynamic meshes.19 In Ref. 18, it is noted that different turbulence models give different normal-force and pitching-moment coefficients. Numerical solutions of the unsteady Euler equations are less expensive than those of the unsteady Navier-Stokes equations. For the unsteady transonic flow, the unsteady Euler equations adequately model most of the real flow features, with the exception of viscous effects whenever they are substantial. The Euler equations model shock waves and their motion, entropy increase across shocks and entropy gradient, and vorticity production and convection behind shocks, as can be seen from Crocco's theorem and the inviscid vorticity transport equa- tion. Recently, successful time-accurate solutions of the un- steady Euler equations have been presented for pitching air- foils19 and wings in transonic flows,20 and for the rolling oscillation of delta wings—a vortex-dominated flow problem in a locally conical supersonic flows.21 To the best of bur knowledge, Ref. 21 is the first work done for unsteady vortex- dominated flows with shock waves, which is directly applica- ble to maneuvering delta wings. In this paper, we present an implicit approximately-factored finite-volume scheme for the time-accurate numerical solution of the unsteady Euler equations of the flow relative motion with respect to an airfoil-fixed frame of reference. The scheme is applied to steady and unsteady transonic flows around a NACA 0012 airfoil. For the unsteady flows, the airfoil is in pitching oscillation about a small and moderate mean angle of attack at a large amplitude. The computational results are compared with the experimental data.
Risk of Incarceration Between Cohorts of Veterans With and Without Mental Illness Discharged From Inpatient Units

Objective: This study examined the risk of incarceration among cohorts of veterans treated in the Department of Veterans Affairs (VA) Connecticut Healthcare System. Incarceration rates of persons with and without mental illness were compared and adjusted for various clinical and service utilization variables. Data were compared before and after the closure of over 80% of the Connecticut VA psychiatric inpatient beds in 1996. Methods: Data from five annual cohorts of patients (1993–1997) treated in an inpatient unit in the VA Connecticut Healthcare System (N=36,385) were merged with state Department of Correction data. Logistic regression models were used to identify risk factors for incarceration. Results: Bivariate analysis showed that incarceration rates were higher for VA patients with psychiatric disorders and with substance use disorders than for those without such diagnoses, but there were no significant increases in likelihood of incarceration over these years of extensive closures. In multiple logistic regression analysis only diagnoses of substance use disorders and major depression were independently associated with an increased likelihood of incarceration, whereas schizophrenia, personality disorders, and co-occurring psychiatric and substance use disorders were not independently associated with increased likelihood in multivariate analysis. Conclusions: Alcohol and drug problems appeared to account for much of the risk of incarceration among hospitalized veterans during the study period. Unlike in previous studies, schizophrenia and related psychotic disorders were not independently associated with an increased risk of incarceration. (Psychiatric Services 59:178–183, 2008)
Optimal equivocation in secrecy systems a special case of distortion-based characterization

Recent work characterizing the optimal performance of secrecy systems has made use of a distortionlike metric for partial secrecy as a replacement for the more traditional metric of equivocation. In this work we use the log-loss function to show that the optimal performance limits characterized by equivocation are, in fact, special cases of distortion-based counterparts. This observation illuminates why equivocation doesn't tell the whole story of secrecy. It also justifies the causal-disclosure framework for secrecy (past source symbols and actions revealed to the eavesdropper).
Empirical models of high latitude electric fields

Model cross sections of the high latitude dawn-dusk electric field based on OGO-6 data are presented for the signature profiles, most frequently encountered for both + and -Y orientations of the interplanetary magnetic field. Line integrals give a total potential of 76 keV in each case. To illustrate extremes, examples of model cross-sections with total potentials of 23 keV and 140 keV are also given. Model convection patterns are also presented utilizing OGO-6 data on boundary locations at other magnetic local times. When this information is combined with characteristic field geometries in the region of the Harang discontinuity, and is supplemented by data from Ba+ cloud motions in the polar cap, it becomes possible to construct realistic convection patterns on the nightside which deviate from the usual sun-aligned patterns. The observational models presented are of limited applicability as a consequence of the variability of observed distributions. These limitations are emphasized with particular attention given to several types of recurrent deviations which have not previously been discussed.
Economies of Scope in Endangered- Species Protection: Evidence from Interest-Group Behavior

Abstract This paper looks for positive spillovers from the legal protection of one species to the welfare of others and for evidence of economies of scope in the costs associated with protecting species under the Endangered Species Act. The analysis uses data on the intensity of interest-group comment activity in response to proposals to protect new species. The results suggest that these phenomena are significant, strengthening arguments that wildlife-protection policy should be shifted toward species groups or ecosystems. However, the findings are also consistent with diminishing public willingness-to-pay for protected species in a given area, a pattern which also has public-policy implications.
The design of the DO preshower detector

This paper describes the basic design parameters, current plans for the readout and trigger electronics and some simulation results of the DO central preshower detector. The DO central preshower detector is designed to improve electron identification and to help restore the electromagnetic energy resolution otherwise degraded by the introduction of one radiation length of material. The cylindrically shaped detector is arranged in z-z, u-u and v-v layers with a uv stereo angle of /spl plusmn/20 degrees. >
Barrier-enhanced InGaAs/InAlAs photodetectors using quantum-well intermixing

Abstract In this work, we model and simulate the performance of a novel InGaAs/InAlAs quantum-well metal–semiconductor–metal (MSM) photodetector at 1550-nm wavelength that utilizes recessed electrodes to access the two-dimensional (2D) transport channel. Unfortunately, rather low Schottky barrier heights on undoped InGaAs lead to excessive dark currents when metal electrodes are in direct contact with this material. To remedy this situation, we propose to form barrier-enhancement regions between the optically active 2D-quantum well and the lateral 3D-metal contacts by means of ion-implantation-induced quantum-well intermixing. Simulation results indicate a reduction in dark current of nearly three orders of magnitude. Additionally, the high-speed performance appears not to be adversely affected under normal operating conditions by the potentially deleterious effects of carrier emission and accumulation at these contact heterointerfaces. The Fourier transform of a simulated transient current response to a light impulse indicates electrical 3-dB bandwidth exceeds 50 GHz in a device with a recessed electrode gap of 1 μm.
Performance Analysis of the IEEE 802.11e Enhanced Distributed Coordination Function Using Cycle Time Approach

The recently ratified IEEE 802.11e standard defines the enhanced distributed channel access (EDCA) function for quality-of-service (QoS) provisioning in the wireless local area networks (WLANs). The EDCA uses carrier sense multiple access with collision avoidance (CSMA/CA) and slotted binary exponential backoff (BEB) mechanism. We present a simple mathematical analysis framework for the EDCA function. Our analysis considers the fact that the distributed random access systems exhibit cyclic behavior where each station successfully transmits a packet in a cycle. Our analysis shows that an AC-specific cycle time exists for the EDCA function. Validating the theoretical results via simulations, we show that the proposed analysis accurately captures EDCA saturation performance in terms of average throughput, medium access delay, and packet loss ratio. The cycle time analysis is a simple and insightful substitute for previously proposed more complex EDCA models.
Plane-wave attenuation anisotropy in orthorhombic media

Orthorhombic models are often used in the interpretation of azimuthally varying seismic signatures recorded over fractured reservoirs. Here, we develop an analytic framework for describing the attenuation coefficients in orthorhombic media with orthorhombic attenuationi.e., the symmetry of both the real and imaginary parts of the stiffness tensor is identical under the assumption of homogeneous wave propagation. The analogous form of the Christoffel equation in the symmetry planes of orthorhombic and VTI transversely isotropic with a vertical symmetry axis media helps to obtain the symmetry-plane attenuation coefficients by adapting the existing VTI equations. To take full advantage of this equivalence with transverse isotropy, we introduce a parameter set similar to the VTI attenuation-anisotropy parametersQ,Q, andQ. This notation, based on the same principle as Tsvankin’s velocity-anisotropy parameters for orthorhombic media, leads to concise linearized equations for the symmetry-plane attenuation coefficients of all three modes P, S1, and S2.The attenuation-anisotropy parameters also allow us to simplify the P-wave attenuation coefficient AP outside the symmetry planes under the assumptions of small attenuation and weak velocity and attenuation anisotropy. The approximate coefficient AP has the same form as the linearized P-wave phase-velocity function, with the velocity parameters
Embeddings of weighted sobolev spaces and generalized Caffarelli-Kohn-Nirenberg inequalities

We characterize all the real numbers a, b, c and 1 ≤ p, q, r < ∞ such that the weighted Sobolev space $$W_{\{ a,b\} }^{\{ q,q\} }({R^N}\backslash \{ 0\} ): = \{ u \in L_{loc}^1({R^N}\backslash \{ 0\} ):{\left| x \right|^{a/q}} \in {L^q}({R^{N),}}{\left| x \right|^{b/p}}\nabla u \in {({L^p}({R^N}))^N}\} $$ is continuously embedded into $${L^r}({R^N};{\left| x \right|^c}dx): = \{ u \in L_{loc}^1({R^N}\backslash \{ 0\} ):{\left| x \right|^{c/r}}u \in {L^r}({R^N})\} $$ with norm ‖·‖ c,r . It turns out that, except when N ≥ 2 and a = c = b − p = −N, such an embedding is equivalent to the multiplicative inequality $${\left\| u \right\|_{c,r}} \le C\left\| {\nabla u} \right\|_{b,p}^\theta \left\| u \right\|_{a,q}^{1 - \theta }$$ for some suitable θ ∈ [0, 1], which is often but not always unique. If a, b, c > −N, then C 0 ∞ (ℝ N ) ⊂ W {} () (ℝ N {0}) ∩ L r (ℝ N ; |x| c dx) and such inequalities for u ∈ C 0 ∞ (ℝ N ) are the well-known Caffarelli-Kohn-Nirenberg inequalities; but their generalization to W {} () (ℝ N {0}) cannot be proved by a denseness argument. Without the assumption a, b, c > −N, the inequalities are essentially new, even when u ∈ C 0 ∞ (ℝ N {0}), although a few special cases are known, most notably the Hardy-type inequalities when p = q. In a different direction, the embedding theorem easily yields a generalization when the weights |x| a , |x| b and |x| c are replaced with more general weights w a ,w b and w c , respectively, having multiple power-like singularities at finite distance and at infinity.
Coloring simple hypergraphs

Fix an integer k>=3. A k-uniform hypergraph is simple if every two edges share at most one vertex. We prove that there is a constant c depending only on k such that every simple k-uniform hypergraph H with maximum degree @D has chromatic number [email protected](H)
Formal total synthesis of (±)-martinellic acid

A concise formal total synthesis of the pyrrolo[3,2-c]quinoline containing natural product, martinellic acid, has been achieved from a pyrroloquinol-2-one through addition of a copper acetylide to an iminium ion. Global deprotection and alkyne reduction then provides the tricyclic triamine, which can be converted to martinelline and martinellic acid.
Nonlinear control via uniform system approximation

Abstract We introduce the notion of uniform system approximation and use it to solve the following problem: Given a single input nonlinear system (f, g): x = f(x) + g(x)u that is linearly controllable on a manifold E of equilibrium points, find vector fields f , g such that (f, g) and f , g agree to first order on E and ( f , g ) is input-to-state linearizable on a neighborhood of E . The solution proceeds by constructing a linearizable uniform system approximation and yields, as a by product, a feedback control law that can be used to guarantee stable operation of the given system in a neighborhood of E . This includes, for example, smooth transitions between operating points that are not necessarily close to each other. A simple example is given to illustrate the approach.
O-Sialylation with N-Acetyl-5-N,4-O-Carbonyl-Protected Thiosialoside Donors in Dichloromethane: Facile and Selective Cleavage of the Oxazolidinone Ring

An N-acetyl-5-N,4-O-carbonyl-protected thiosialoside donor, the structure of which has been defined through X-ray crystallography, was prepared and tested in couplings to a wide range of acceptors. This donor gives excellent yields and α-selectivities in linking with various primary alkyl and carbohydrate acceptors under the N-iodosuccinimide and trifluoromethanesulfonic acid in situ activation method at −40 °C in dichloromethane. The favorable affect of the oxazolidinone substructure for α-sialylation is illustrated by a comparison study with a N,N-diacetylsialyl donor, which exhibited inferior yields and α-selectivities. The sialylation selectivity is independent of the anomeric configuration of the donor, but is highly related to the reaction temperature under the NIS/TfOH activation method. In contrast to the NIS/TfOH method, the Ph2SO/Tf2O promotion gives β-selective couplings in dichloromethane. The oxazolidinone of the N-acetyl-5-N,4-O-carbonyl protected sialosides, both α- and β-anomers, could be ...
Adequacy of Decompositions of Relational Databases

We consider conditions that have appeared in the literature with the purpose of defining a “good” decomposition of a relation scheme. We show that these notions are equivalent in the case that all constraints in the database are functional dependencies. This result solves an open problem of Rissanen. However, for arbitrary constraints the notions are shown to differ.
Molecular structure and biological and pharmacological properties of 3-hydroxy-2-methyl-1-(β-D-ribofuranosyl or pyranosyl)-4-pyridinone: potential iron overload drugs for oral administration

Abstract Replacing alkyl groups by sugar moieties at N-1 position of 3-hydroxyl-2-methyl-4-pyridinone did not affect the geometry of the iron chelating sites but increased the hydrophilic nature. The formation of a polymer cluster through the intermolecular hydrogen bonds was also revealed by X-ray crystal structure analysis for the first time in all known 3-hydroxy-4-pyridinone crystal structures. Iron removal from ferritin by the title compounds was more efficient than with DFO.
Development of adaptive protection scheme for distribution systems with high penetration of distributed generation

Conventional power distribution system is radial in nature, characterized by a single source feeding a network of downstream feeders. Protection scheme for distribution system, primarily consisting of fuses and reclosers and, in some cases, relays, has traditionally been designed assuming the system to be radial. After connecting distributed generation (DG), part of the system may no longer be radial, which means the coordination might not hold. The effect of DG on coordination will depend on size, type, and placement of DG. This paper explores the effect of high DG penetration on protective device coordination and suggests an adaptive protection scheme as a solution to the problems identified. Results of implementation of this scheme on a simulated actual distribution feeder are reported.
Extractors for varieties

We study the task of randomness extraction from sources that are distributed uniformly on an unknown algebraic variety. In other words, we are interested in constructing a function (an extractor) whose output is close to uniform even if the input is drawn uniformly from the set of solutions of an unknown system of low degree polynomials. This problem generalizes the problem of extraction from affine sources which has drawn a considerable amount of interest lately. We present two constructions of explicit extractors for varieties. The first works for varieties of any size (including one-dimensional varieties or curves) and requires field size that is exponential in the overall dimension of the space. Our second extractor allows the field size to be polynomial in the degree of the equations defining the variety, but works only for varieties whose size is at least the square root of the total size of the space.
Scalable Implementation of Boson Sampling with Trapped Ions

Boson sampling solves a classically intractable problem by sampling from a probability distribution given by matrix permanents. We propose a scalable implementation of boson sampling using local transverse phonon modes of trapped ions to encode the bosons. The proposed scheme allows deterministic preparation and high-efficiency readout of the bosons in the Fock states and universal mode mixing. With the state-of-the-art trapped ion technology, it is feasible to realize boson sampling with tens of bosons by this scheme, which would outperform the most powerful classical computers and constitute an effective disproof of the famous extended Church-Turing thesis.
Quantum Sensors: Improved Optical Measurement via Specialized Quantum States

Classical measurement strategies in many areas are approaching their maximum resolution and sensitivity levels, but these levels often still fall far short of the ultimate limits allowed by the laws of physics. To go further, strategies must be adopted that take into account the quantum nature of the probe particles and that optimize their quantum states for the desired application. Here, we review some of these approaches, in which quantum entanglement, the orbital angular momentum of single photons, and quantum interferometry are used to produce optical measurements beyond the classical limit.
Collaborative caching for efficient dissemination of personalized video streams in resource constrained environments

The ever increasing deployment of broadband networks and simultaneous proliferation of low-cost video capturing and multimedia-enabled mobile devices such as smart cellular phones, netbook computers, and tablet computers have triggered a wave of novel mobile multimedia applications making video streaming on mobile devices increasingly popular and commonplace. Networked environments consisting of mobile devices tend to be highly heterogeneous in terms of client-side and system-wide resource constraints, clients' queries for information, geospatial distribution, and dynamic trajectories of the mobile clients, and client-side and server-side privacy and security requirements. Invariably, the video streams need to be personalized to provide a resource-constrained mobile device with video content that is most relevant to the client's request while simultaneously satisfying the client-side and system-wide resource constraints, privacy and security requirements and the constraints imposed by the geospatial distribution and dynamic trajectories of the mobile clients relative to the server(s). In this paper, we present the design and implementation of a distributed system, consisting of several geographically distributed video personalization servers and proxy caches, for efficient dissemination of personalized video in a resource-constrained mobile environment. With the objective of optimizing cache performance, a novel cache replacement policy and multi-stage client request aggregation strategy, both of which are specifically tailored for personalized video content, are proposed. A novel Latency-Biased Collaborative Caching (LBCC) protocol based on counting Bloom filters is designed for further enhancing the scalability and efficiency of disseminating personalized video content. The benefits and costs associated with collaborative caching for disseminating personalized video content to resource-constrained and geographically distributed clients are analyzed and experimentally verified. The impact of different levels of collaboration among the caches and the advantages of using multiple video personalization servers with varying degrees of mirrored content on the efficiency of personalized video delivery are also studied. Experimental results demonstrate that the proposed collaborative caching scheme, coupled with the proposed personalization-aware cache replacement and client request aggregation strategies, provides a means for efficient dissemination of personalized video streams in resource-constrained environments.
Access to bicyclic hydroxamate macrocycles via intramolecular aza-(4 + 3) cyloaddition reactions of aza-oxyallylic cation intermediates

The intramolecular aza-(4 + 3) cycloaddition reactions of in situ generated aza-oxyallylic cations and furans have been reported for the construction of medium sized hydroxamate macrocycles. This method provides direct access to 12–18 membered bicyclic macrocycles. The highly functionalized macrocycles have been transformed easily in to a wide range of highly functionalized heterocyclic scaffolds including lactones and lactams that could serve the synthesis of complex macrocyclic natural products and pharmaceuticals.
Mollenynes B–E from the Marine Sponge Spirastrella mollis. Band-Selective Heteronuclear Single Quantum Coherence for Discrimination of Bromo–Chloro Regioisomerism in Natural Products

Four new chlorobromohydrins, mollenynes B-E, were isolated from the marine sponge Spirastrella mollis collected from Hogsty Reef, Bahamas. Their structures were elucidated by integrated analysis of NMR, MS, and computational methods. A high-resolution band-selective HSQC experiment was developed to identify (13)C NMR signals in samples at the nanomole-scale that arise from Cl-substituted (13)C by exploiting the (35)Cl/(37)Cl isotope shift.
Silicon-chip-based optical frequency combs

Generation of optical frequency combs using Silicon-based photonics offers the potential for highly robust, compact, low-power devices for a wide range of applications in time and frequency metrology, sensing, spectroscopy, and communications.
Intercalation in two-dimensional transition metal chalcogenides

Intercalation is a reversible insertion process of foreign species into crystal gaps. Layered materials are good host materials for various intercalant species ranging from small ions to atoms to molecules. Given the recent intense interest in two-dimensional (2D) layered materials in thin limits, this review highlights the opportunities that intercalation chemistry can provide for nanoscale layered materials. Novel heterostructures or emergent electrical properties not found in the intrinsic host materials are possible with intercalation. In particular, we review various exfoliation methods developed for 2D layered nanomaterials based on intercalation chemistry and extensive tuning of the electrical, optical, and magnetic properties of 2D layered materials due to intercalation.
Beauty, gender and stereotypes : Evidence from laboratory experiments

The existence of a beauty premium in the labor market and the male-female wage gap suggests that appearance can matter in the real world. We explore beauty and gender in a public goods experiment and find similar effects. We find a beauty premium, even though beautiful people contribute, on average, no more or less than others. The beauty premium, however, disappears when we provide information on individual contributions, and becomes a beauty penalty. Players seem to expect beautiful people to be more cooperative. Relative to these expectations, they appear more selfish, which in turn results in less cooperation by others. These appear to be clear examples of stereotyping. We also find a substantial benefit to being male, especially with information. This is primarily due to men being better "leaders." Men tend to make large contributions, and people follow their example and give more in later rounds.
Interpreting the Dependence of Mutation Rates on Age and Time.

Mutations can originate from the chance misincorporation of nucleotides during DNA replication or from DNA lesions that arise between replication cycles and are not repaired correctly. We introduce a model that relates the source of mutations to their accumulation with cell divisions, providing a framework for understanding how mutation rates depend on sex, age, and cell division rate. We show that the accrual of mutations should track cell divisions not only when mutations are replicative in origin but also when they are non-replicative and repaired efficiently. One implication is that observations from diverse fields that to date have been interpreted as pointing to a replicative origin of most mutations could instead reflect the accumulation of mutations arising from endogenous reactions or exogenous mutagens. We further find that only mutations that arise from inefficiently repaired lesions will accrue according to absolute time; thus, unless life history traits co-vary, the phylogenetic “molecular clock” should not be expected to run steadily across species.