cssi/SciSciGPT-SciSciNet huggingface dataset:
Learning abstract concepts through interactive playing

In this paper, we present strategies and approaches used to implement a synthetic learning environment which includes distributed interactive simulation, computational steering, interactive visualization, and artificial intelligence for learning abstract scientific concepts and entertainment. We use Navier-Stokes equations as a case study to show our ideas and methods. Students are allowed to interact with one another and engage in realistic collaborative exercises. The resulting technology is a testbed that reflects the benefits of a schoolhouse for training and education, especially for scientific abstract concepts, yet does not have the physical limitation that instructors, students and resources be collocated both spatially and temporally. Our innovative use of computational steering and interactive visualization allows students to visualize and manipulate the physical process, and understand the abstract concept through entertainment.
Infrastructure-Free Logging and Replay of Concurrent Execution on Multiple Cores

We develop a logging and replay technique for real concurrent execution on multiple cores. Our technique directly works on binaries and does not require any hardware or complex software infrastructure support. We focus on minimizing logging overhead as it only logs a subset of system calls and thread spawns. Replay is on a single core. During replay, our technique first tries to follow only the event order in the log. However, due to schedule differences, replay may fail. An exploration process is then triggered to search for a schedule that allows the replay to make progress. Exploration is performed within a window preceding the point of replay failure. During exploration, our technique first tries to reorder synchronized blocks. If that does not lead to progress, it further reorders shared variable accesses. The exploration is facilitated by a sophisticated caching mechanism. Our experiments on real world programs and real workload show that the proposed technique has very low logging overhead 2.6% on average and fast schedule reconstruction.
The Security of Chaffing and Winnowing

This paper takes a closer look at Rivest's chaffing-and-winnowing paradigm for data privacy.We begin with a definition which enables one to clearly determine whether a given scheme qualifies as "chaffing-and-winnowing." We then analyze Rivest's schemes to see what quality of data privacy they provide. His bit-by-bit scheme is easily proven secure but is inefficient. His more efficient scheme --based on all-or-nothing transforms (AONTs)-- can be attacked under Rivest's definition of security of an AONT, and even under stronger notions does not appear provable. However we show that by using OAEP as the AONT one can prove security, and also present a different scheme, still using AONTs, that is equally efficient and easily proven secure even under a relatively weak notion of security of AONTs.
On the geometric and topological rigidity of hyperbolic 3-manifolds

Theorem 0.1. Let N be a closed hyperbolic 3-manifold containing an embedded hyperbolic tube of radius (log 3)/2 = .549306... about a closed geodesic. Then i) Iff : M N is a homotopy equivalence where M is an irreducible 3-manifold, then f is homotopic to a homeomorphism. ii) If f, g: M -s N are homotopic homeomorphisms, then f is isotopic to g. iii) The space of hyperbolic metrics on N is path connected.
Baire spaces and infinite games

It is well known that if the nonempty player of the Banach---Mazur game has a winning strategy on a space, then that space is Baire in all powers even in the box product topology. The converse of this implication may also be true: We know of no consistency result to the contrary. In this paper we establish the consistency of the converse relative to the consistency of the existence of a proper class of measurable cardinals.
Phoenix: an epidemic approach to time reconstruction

Harsh deployment environments and uncertain run-time conditions create numerous challenges for postmortem time reconstruction methods. For example, motes often reboot and thus lose their clock state, considering that the majority of mote platforms lack a real-time clock. While existing time reconstruction methods for long-term data gathering networks rely on a persistent basestation for assigning global timestamps to measurements, the basestation may be unavailable due to hardware and software faults. We present Phoenix, a novel offline algorithm for reconstructing global timestamps that is robust to frequent mote reboots and does not require a persistent global time source. This independence sets Phoenix apart from the majority of time reconstruction algorithms which assume that such a source is always available. Motes in Phoenix exchange their time-related state with their neighbors, establishing a chain of transitive temporal relationships to one or more motes with references to the global time. These relationships allow Phoenix to reconstruct the measurement timeline for each mote. Results from simulations and a deployment indicate that Phoenix can achieve timing accuracy up to 6 ppm for 99% of the collected measurements. Phoenix is able to maintain this performance for periods that last for months without a persistent global time source. To achieve this level of performance for the targeted environmental monitoring application, Phoenix requires an additional space overhead of 4% and an additional duty cycle of 0.2%.
Super‐Dense Matter at Super‐ Strong Magnetic Fields

Our Universe is full of regions where extreme physical conditions are realized. A most intriguing case is the super‐dense core of neutron stars, some of which also have super‐strong magnetic fields, hence called magnetars. In this paper we review the current understanding of the physical properties of the different phases of quark matter at very high densities in the presence of large magnetic fields. We also discuss how the Meissner instability produced at moderate densities by a pairing stress due to the medium neutrality and β‐equilibrium constraints can lead to the spontaneous generation of a magnetic field.
Dynamic compressive behavior of unidirectional E-glass/vinylester composites

Results from an experimental investigation on the mechanical behavior of unidirectional fiber reinforced polymer composites (E-glass/vinylester) with 30%, 50% fiber volume fraction under dynamic uniaxial compression are presented. Specimens are loaded in the fiber direction using a servo-hydraulic material testing system for low strain rates and a Kolsky (split Hopkinson) pressure bar for high strain rates, up to 3000/s. The results indicate that the compressive strength of the composite increases with increasing strain rate. Post-test scanning electron microscopy is used to identify the failure modes. In uniaxial compression the specimens are split axially (followed by fiber kink band formation). Based on the experimental results and observations, an energy-based analytic model for studying axial splitting phenomenon in unidirectional fiber reinforced composites is extended to predict the compressive strength of these composites under dynamic uniaxial loading condition.
Mandates, Tax Credits, and Tariffs: Does the U.S. Biofuels Industry Need Them All?

Expanded mandates under the Renewable Fuel Standard provide ethanol and biodiesel producers a guaranteed future market at volumes that exceed what they have produced in the past. Despite having these mandates in place, biofuel producers continue to support tax credits and ethanol import tariffs. An examination of how the new mandates will be implemented shows that biofuel producers will receive little or no additional benefit from tax credits. Ethanol import tariffs will continue to provide U.S. corn ethanol producers a cost advantage over imported Brazilian sugarcane ethanol until at least 2013 when the demand for sugarcane ethanol to meet the noncellulosic advanced biofuel mandate starts to increase.
Prophet inequalities with limited information

In the classical prophet inequality, a gambler observes a sequence of stochastic rewards V1, ..., Vn and must decide, for each reward Vi, whether to keep it and stop the game or to forfeit the reward forever and reveal the next value Vi. The gambler's goal is to obtain a constant fraction of the expected reward that the optimal offline algorithm would get. Recently, prophet inequalities have been generalized to settings where the gambler can choose k items, and, more generally, where he can choose any independent set in a matroid. However, all the existing algorithms require the gambler to know the distribution from which the rewards V1, ..., Vn are drawn.The assumption that the gambler knows the distribution from which V1, ..., Vn are drawn is very strong. Instead, we work with the much simpler assumption that the gambler only knows a few samples from this distribution. We construct the first single-sample prophet inequalities for many settings of interest, whose guarantees all match the best possible asymptotically, even with full knowledge of the distribution. Specifically, we provide a novel single-sample algorithm when the gambler can choose any k elements whose analysis is based on random walks with limited correlation. In addition, we provide a black-box method for converting specific types of solutions to the related secretary problem to single-sample prophet inequalities, and apply it to several existing algorithms. Finally, we provide a constant-sample prophet inequality for constant-degree bipartite matchings.In addition, we apply these results to design the first posted-price and multi-dimensional auction mechanisms with limited information in settings with asymmetric bidders. Connections between prophet inequalities and posted-price mechanisms are already known, but applying the existing framework requires knowledge of the underlying distributions, as well as the so-called "virtual values" even when the underlying prophet inequalities do not. We therefore provide an extension of this framework that bypasses virtual values altogether, allowing our mechanisms to take full advantage of the limited information required by our new prophet inequalities.
Seeing through black boxes: Tracking transactions through queues under monitoring resource constraints

The problem of optimal allocation of monitoring resources for tracking transactions progressing through a distributed system, modeled as a queueing network, is considered. Two forms of monitoring information are considered, viz., locally unique transaction identifiers, and arrival and departure timestamps of transactions at each processing queue. The timestamps are assumed to be available at all the queues but in the absence of identifiers, only enable imprecise tracking since parallel processing can result in out-of-order departures. On the other hand, identifiers enable precise tracking but are not available without proper instrumentation. Given an instrumentation budget, only a subset of queues can be selected for the production of identifiers, while the remaining queues have to resort to imprecise tracking using timestamps. The goal is then to optimally allocate the instrumentation budget to maximize the overall tracking accuracy. The challenge is that the optimal allocation strategy depends on accuracies of timestamp-based tracking at different queues, which has complex dependencies on the arrival and service processes, and the queueing discipline. We propose two simple heuristics for allocation by predicting the order of timestamp-based tracking accuracies of different queues. We derive sufficient conditions for these heuristics to achieve optimality through the notion of the stochastic comparison of queues. Simulations show that our heuristics are close to optimality, even when the parameters deviate from these conditions.
Symplectic tori in homotopy E(1)'S

This short note presents a simple construction of nonisotopic symplectic tori representing the same primitive homology class in the symplectic 4-manifold E(1) K , obtained by knot surgery on the rational elliptic surface E(1) = P 2 #9P 2 with the left-handed trefoil knot K. E(1) K has the simplest homotopy type among simply-connected symplectic 4-manifolds known to exhibit such a property.
Portal Monitor for Diversion Safeguards

Two prototype doorway monitors to deter the diversion of special nuclear materials have been designed and constructed. One prototype utilizes plastic scintillators while the other contains NaI(Tl) ...
Regions of time and internet: modelling: an application of the space-time trip (RASTT) model to the USA internet market

The mathematical analysis of the Internet and World Wide Web (WWW) is distinctly aspatial at present, with the transaction flows defined specifically by time-dependent indices (such as, the Internet Weather Report). How should the Internet and WWW be viewed as a geographical system where both space and time are fundamental to interaction? The retail aggregate space-time (RASTT) model has been developed previously to study trips to and from shopping malls and this model may provide some insights into the framing of this question. The RASTT model can be developed from a time-dependent random walk from an ensemble of home-based computers sending and receiving transactions through a network of sites. The spatial solution forms very weak gravity interactions and the time-dependent solutions are demand waves circumnavigating the Earth. Recent experimental results from Microsoft Research support these conclusions. These flows have the interesting property of moving either forwards or backwards through regions of time relative to the rotation of the Earth. The model can be developed to show bias in flows to USA sites and by using similarity arguments, the transaction demand wave across the USA can be derived by using a power law assumption of network connectivity.
Trapped ion quantum computer research at los alamos

We briefly review the development and theory of an experiment to investigate quantum computation with trapped calcium ions. The ion trap, laser and ion requirements are determined, and the parameters required for simple quantum logic operations are described. (LAUR 98-314).
Feedback from freeze-out in hydrodynamics

Most hydrodynamical calculations used in heavy-ion physics ignore the effect of freeze-out matter carrying energy and momentum away from the expanding fluid. In a simple one-dimensional model we compare calculated energy density and velocity profiles, with and without interaction between fluid-like and freeze-out parts of the system, in order to estimate the importance of this effect.
Temperature-dependent ion beam mixing

Recent work addressing the enhanced interdiffusion rates typically observed during ion-beam mixing at elevated temperatures is reviewed. As discussed previously, the expected increase in ion-beam mixing rates due to “radiation-enhanced diffusion” (RED), i.e. the free migration of isolated vacancy and interstitial defects, is well documented in single-crystal specimens in the range of 0.4 to 0.6 of the absolute melting temperature. In contrast, the increase often observed at somewhat lower temperatures during ion-beam mixing of polycrystalline specimens is not well understood. However, sufficient evidence is available to show that this increase reflects intracascade enhancement of a thermally-activated process that also occurs in the absence of irradiation. Recent evidence is presented which suggests that this process is Diffusion-Induced Grain-Boundary Migration (DIGM). An important complementary conclusion is that because ion-beam mixing in single-crystal specimens exhibits no significant temperature dependence below that of RED, models that invoke only irradiation-specific phenomena, e.g., cascade-overlap, thermal-spikes, or liquid-diffusion, and hence which predict no difference in mixing behavior between single- or poly-crystalline specimens, cannot account for the existing results.
Nonconjugate ULF wave power observed by ground magnetometers in the northern and southern dayside cusp/Cleft/LLBL regions

Long-period broadband waves (∼1-50 mHz) have been known for many years to be a dominant feature in the ULF wave spectrum in the dayside cusp/cleft/LLBL region. Multistation studies have shown that such activity cannot be simply associated with boundary layer or cusp proximity; instead it shows a coordinated time dependence across several hours of local time. Recently, this high-latitude broadband wave activity was found to often not be simultaneous in conjugate hemispheres. Earlier studies of magnetic impulse events and riometer data in conjugate high latitude locations showed similar behavior. We present here observations of an extended period of nonconjugate broadband pulsations, and demonstrate that the hemispheric differences can even extend into regions of normally closed field lines. Comparisons of wave activity at latitudinally spaced stations suggest that narrowband Pc 5 wave power at auroral latitudes is directly associated with, and may be stimulated by, the broadband wave activity at cusp/cleft/LLBL latitudes in either or both hemispheres. There were extended intervals on this day with a large By component of the interplanetary magnetic field, but these occurred during times of both conjugate and nonconjugate wave activity. These and other observations suggest a possible source of broadband ULF variations in the high-altitude cusp/boundary layer/entry layer regions in each hemisphere, rather than or in addition to a common source at or near the equatorial magnetopause/LLBL.
Analyzing Trade Competitiveness : A Diagnostics Approach

Trade has proven to be a powerful engine of growth worldwide. But not all countries have benefited equally. Despite much effort to use trade policy to catalyze exports, many developing countries have failed to achieve successful, sustainable export and economic growth. Even with the benefit of preferential market access, many developing country exporters face a broad and diverse set of constraints that limit their potential to compete in export markets. This paper discusses the concept of competitiveness with respect to trade and the various dimensions on which trade competitiveness might be assessed. It argues there is a need for a framework by which trade competitiveness can be assessed in a systematic way. Inspired by the growth diagnostics approach, it outlines a possible framework for assessing factors that facilitate or constrain trade competitiveness.
Spectral observations of the diffuse FUV background with DUVE (the diffuse UV experiment)

We present results from a search for FUV emission from the diffuse ISM conducted with an orbital FUV spectrometer, DUVE, which was launched in July, 1992. The DUVE spectrometer, which covers the band from 950 A to 1080 A with 3.2 A resolution, observed a region of low neutral hydrogen column density near the south galactic pole for a total effective integration time of 1583 seconds. the only emission line detected was a geocoronal hydrogen line at 1025 A. We were able to place upper limits to several emission features that provide constraints to interstellar plasma parameters. We were also able to place continuum limits in this band. We use these upper limits to place constraints upon the emission measure vs. temperature distribution of this gas using an isothermal Landini and Fossi model.
Shock Origin of High-Velocity Maser Emission from: Circumnuclear Disks

We propose that the observed high-velocity maser emission from circumnuclear disks arises in spiral shocks, which can naturally account for several peculiar findings in the spectrum and spatial distribution of the maser emission.
Transient X-Ray Sources with Late-Type Companions

In a few short-period (P≲1 day) X-ray binaries it is possible to observe the late-type secondary. Two examples are the X-ray novae Cen X-4 and A0620–00. Optical studies have shown that the degenerate star in the former has the mass expected for a neutron star, whereas the compact object in the latter is considerably more massive and is a likely black hole. Another binary, 4U2129+47, which was a persistent X-ray source for at least several years, has been in an X-ray “off” state since mid 1983. Its optical appearance and behavior in the off state are wholly unexpected and puzzling given the compelling model that was developed earlier when the source was X-ray active. A fourth transient source discussed here, EXO 0748–676, is a 3.8-hour eclipsing binary, which has provided a fresh look at the properties of neutron-star shell flashes and accretion-disk coronae.
Dynamics of Magnetization Reversal in Models of Magnetic Nanoparticles and Ultrathin Films

We discuss numerical and theoretical results for models of magnetization switching in nanoparticles and ultrathin films. The models and computational methods include kinetic Ising and classical Heisenberg models of highly anisotropic magnets which are simulated by dynamic Monte Carlo methods, and micromagnetics models of continuum-spin systems that are studied by finite-temperature Langevin simulations. The theoretical analysis builds on the fact that a magnetic particle or film that is magnetized in a direction antiparallel to the applied field is in a metastable state. Nucleation theory is therefore used to analyze magnetization reversal as the decay of this metastable phase to equilibrium. We present numerical results on magnetization reversal in models of nanoparticles and films, and on hysteresis in magnets driven by oscillating external fields.
QUANTUM LIQUID CRYSTAL PHASES IN FERMIONIC SUPERFLUIDS WITH PAIRING BETWEEN FERMION SPECIES OF UNEQUAL DENSITIES

Superfluidity in fermionic systems originates from pairing of fermions, and Bose condensation of these Cooper pairs. The Cooper pairs are usually made of fermions of different species; thus the most favorable situation for pairing and superfluidity is when the two species of fermions that form pairs have the same density. This paper studies the possible superfluid states when the two pairing species have different densities, and show that the resultant states have remarkable similarities to the phases of liquid crystals. This enables us to provide a unified description of the possible pairing phases and understand the phase transitions among them.
Land Accumulation Dynamics in Developing Country Agriculture

AbstractUnderstanding land accumulation dynamics is relevant for policy-makers interested in the economic effects of land inequality in developing country agriculture. We thus explore and simultaneously test the leading theories of micro-level land accumulation dynamics using unique panel data from Paraguay. The results suggest that farm growth varies systematically with farm size – a formal rejection of stochastic growth theories (that is, Gibrat’s Law) – and that titled land area may have considerable influence on land accumulation. Furthermore, our estimates indicate that a dualistic agrarian structure is the likely product of the unfettered operation of land markets.
Overlap Number of Graphs

An overlap representation of a graph G assigns sets to vertices so that vertices are adjacent if and only if their assigned sets intersect with neither containing the other. The overlap number φ(G) (introduced by Rosgen) is the minimum size of the union of the sets in such a representation. We prove the following: (1) An optimal overlap representation of a tree can be produced in linear time, and its size is the number of vertices in the largest subtree in which the neighbor of any leaf has degree 2. (2) If δ(G)⩾2 and G≠K3, then φ(G)⩽|E(G)| − 1, with equality when G is connected and triangle-free and has no star-cutset. (3) If G is an n-vertex plane graph with n⩾5, then φ(G)⩽2n − 5, with equality when every face has length 4 and there is no star-cutset. (4) If G is an n-vertex graph with n⩾14, then φ(G)⩽n2/4 − n/2 − 1, with equality for even n when G arises from Kn/2, n/2 by deleting a perfect matching. © 2012 Wiley Periodicals, Inc. (Contract grant sponsors: NSF (to N. K.); NSF; Contract grant number: DMS 08-38434 (to K. G. M.); Contract grant sponsor: NSA; Contract grant numbers: H98230-06-1-0065; H98230-10-1-0363 (to D. B. W.). Nitish Korula and Kevin G. Milans participated in this research while at the University of Illinois, supported in part by a Dissertation Completion Fellowship.)
Specification of >2 MeV geosynchronous electrons based on solar wind measurements

[1] Relativistic electron flux measurements from geosynchronous satellites show a local time dependence. This local time dependence is due to the radial profile of the electron fluxes and the dayside/nightside asymmetry of the Earth's magnetosphere and is also affected by geomagnetic activity, which is in turn affected by the solar wind. Statistical asynchronous regression (SAR), a statistical method recently adapted for magnetospheric studies, was used to determine the relationship between electron fluxes measured at different local times, as a function of the Kp index (O'Brien et al., 2001). In this study, we use measurements directly from the solar wind, instead of the Kp index, and the SAR method as the basis for determining the local time dependence of geosynchronous energetic electron fluxes. We use solar wind parameters as input in our model to map GOES 10 > 2 MeV electron measurements to other local times and compare them with electron measurements from five widely spaced LANL geosynchronous satellites when they pass through these local times. We cross calibrate the electron measurements from the five LANL satellites and find that the averaged electron flux from individual satellites can differ by up to 50% even though the particle detectors were identically designed. In this study, we normalize measurements from each LANL spacecraft to the average value of all five LANL spacecraft. We also cross calibrate the electron measurements from the LANL satellites and from GOES 10 and find that the energy spectrum is best described by a power law index which is a function of the current average LANL 1.1–1.5 MeV electron flux level. We explore the effects of solar wind velocity, dynamic pressure, and density on the local time dependence of geosynchronous electron fluxes. We find that for the given 4.3 year data set, using only solar wind velocity gives rise to the best results. We check the efficacy of the model by mapping GOES 10 > 2 MeV electron measurements at other local times to local noon and comparing with electron measurements from LANL satellites when they pass through local noon: We achieve an out-of-sample prediction efficiency (PE) of 0.83 and a linear correlation coefficient (LC) of 0.93 for January 2000, whereas we achieve a PE of 0.81 and LC of 0.92 for the year 2000. The PE and LC are different when mapping GOES 10 > 2 MeV electron measurements at one local time to other local times, with the highest PE around prenoon and afternoon and the lowest near midnight.
Mauritania : counting on natural wealth for a sustainable future

A data set of key macro-sustainability indicators, constructed after several fact-finding missions, and World Bank methodologies on estimating wealth accounting are used to study Mauritania's wealth, which is estimated to be between USD50 and USD60 billion. The country's produced wealth represents roughly 12 percent of total wealth, much less than in lower-middle-income countries; by contrast, natural wealth represents approximately 45 percent of the total figure. Renewable resources account for slightly less than two-thirds of natural wealth, with fisheries alone equaling about one-fourth of natural wealth. This is good news for Mauritania, as sound management of these resources may ensure a constant flow of resources in the future and therefore -- with adequate policies -- the achievement of the same or higher levels of welfare for future generations. On the negative side, however, the ratio of net adjusted savings over gross national income is estimated to have been negative since 2006, meaning that the wealth of the country is being depleted. Mauritania has recently joined the ranks of lower-middle-income countries, largely thanks to its considerable natural resources endowment. Over time the mining sector's contribution to gross domestic product has grown significantly and important discoveries continue to be made. The overarching objective of this wealth accounting exercise is thus to support Mauritania to measure its assets better and achieve a more complete picture of the prospects for future income, with a view to better orienting public policies toward sustainable growth and shared prosperity. The paper concludes with several indicative policy recommendations.
Chapter 7 – Continuous Change

Discrete change is change that is limited to a countable, usually finite, set of time points. The chapter represents, discrete change in the event calculus using effect axioms. In a number of commonsense domains ranging from the physical to the mental, one can find continuous change. This chapter discusses the representation of continuous change and gradual change in the event calculus. We retrace the development of Trajectory. It also discusses the use of trajectory and antitrajectory axioms. Axiomatizations describes a falling object, it fails to capture the commonsense knowledge about falling objects. Namely, when an object is dropped, it starts to fall; when an object hits the ground, it stops falling. Therefore, one can integrate events into representation of continuous change. One event will set in motion an episode of continuous change, whereas another event will stop the episode. The chapter uses fluents to represent episodes of continuous change.
Quantum maps and automorphisms

There are several inequivalent definitions of what it means to quantize a symplectic map on a symplectic manifold (M, ω). One definition is that the quantization is an automorphism of a *-algebra associated to (M, ω). Another is that it is unitary operator U χ on a Hilbert space associated to (M, ω), such that A → U χ * AU χ defines an automorphism of the alge of observables. A yet stronger one, common in partial differential equations, is that U χ should be a Fourier integral operator associated to the graph of χ. We compare the definiti in the case where (M, ω) is a compact Kahler manifold. The main result is a Toeplitz analogue of the Duistermaat—Singer theorem on automorphisms of pseudodifferential algebras, and an extension which does not assume H 1(M,ℂ) = {0}. We illustrate with examples from quantum maps.
The Long-term Impact of Medicare Payment Reductions on Patient Outcomes

Objective To examine the long-term impact of Medicare payment reductions on patient outcomes for Medicare acute myocardial infarction (AMI) patients.
Generating raster DEM from mass points via TIN streaming

It is difficult to generate raster Digital Elevation Models (DEMs) from terrain mass point data sets too large to fit into memory, such as those obtained by LIDAR. We describe prototype tools for streaming DEM generation that use memory and disk I/O very efficiently. From 500 million bare-earth LIDAR double precision points (11.2 GB) our tool can, in just over an hour on a standard laptop with two hard drives, produce a 50,394 × 30,500 raster DEM with 20 foot post spacing in 16 bit binary BIL format (3 GB), using less than 100 MB of main memory and less than 300 MB of temporary disk space.
Catalytic asymmetric hydroamination of unactivated internal olefins to aliphatic amines

Catalytic assembly of enantiopure aliphatic amines from abundant and readily available precursors has long been recognized as a paramount challenge in synthetic chemistry. Here, we describe a mild and general copper-catalyzed hydroamination that effectively converts unactivated internal olefins—an important yet unexploited class of abundant feedstock chemicals—into highly enantioenriched α-branched amines (≥96% enantiomeric excess) featuring two minimally differentiated aliphatic substituents. This method provides a powerful means to access a broad range of advanced, highly functionalized enantioenriched amines of interest in pharmaceutical research and other areas.
Colloquium : Electron-lattice interaction and its impact on high T c superconductivity

In this Colloquium, the main features of the electron-lattice interaction are discussed and high values of the critical temperature up to room temperature could be provided. While the issue of the mechanism of superconductivity in the high ${T}_{c}$ cuprates continues to be controversial, one can state that there have been many experimental results demonstrating that the lattice makes a strong impact on the pairing of electrons. The polaronic nature of the carriers is also a manifestation of strong electron-lattice interaction. One can propose an experiment that allows an unambiguous determination of the intermediate boson (phonon, magnon, exciton, etc.) which provides the pairing. The electron-lattice interaction increases for nanosystems, and this is due to an effective increase in the density of states.
Multidimensional Correlation Spectroscopy by Covariance NMR

An introduction is presented to covariance nuclear magnetic resonance (NMR) spectroscopy, which is a multidimensional method that characterizes physical spin correlations by their statistical covariances. In its simplest form, covariance NMR endows the indirect dimension of a homonuclear two-dimensional (2D) NMR spectrum with the same high resolution as the direct dimension and thereby enhances the spectral resolution, reduces the experimental NMR time, or both. This property makes covariance NMR useful for applications where rapid acquisition of high-resolution data is important, including structural genomics and metabolomics. Over the recent past, covariance NMR has been generalized along different lines. This includes the application of covariance NMR to higher-dimensional NMR, such as 13C and 15N-edited 4D nuclear Overhauser enhancement spectroscopy (NOESY) spectra, to obtain spectra at resolutions that are not readily achievable by standard 4D Fourier transform spectroscopy. Indirect covariance NMR transforms one or more 2D NMR spectra to obtain correlation information whose direct experimental measurement would be difficult for sensitivity reasons. This article explains both concepts and practical aspects of covariance NMR for the processing and analysis of common types of NMR data. Keywords: covariance NMR; indirect covariance; resolution enhancement; sensitivity; multidimensional NMR
Assessment of folate receptor-β expression in human neoplastic tissues.

// Jiayin Shen 1 , Karson S. Putt 2 , Daniel W. Visscher 3 , Linda Murphy 4 , Cynthia Cohen 5 , Sunil Singhal 6 , George Sandusky 7 , Yang Feng 8 , Dimiter S. Dimitrov 8 and Philip S. Low 1,2 1 Department of Chemistry, Purdue University, West Lafayette, IN, USA 2 Center for Drug Discovery, Purdue University, West Lafayette, IN, USA 3 Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA 4 Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Rochester, MN, USA 5 Department of Pathology and Laboratory Medicine, Emory University Hospital, Atlanta, GA, USA 6 Division of Thoracic Surgery, Department of Surgery, Hospital of the University of Pennsylvania School of Medicine, Philadelphia, PA, USA 7 Department of Pathology, Indiana University School of Medicine, Indianapolis, IN, USA 8 Protein Interactions Section, Laboratory of Experimental Immunology, Cancer and Inflammation Program, Center for Cancer, National Cancer Institute-Frederick, National Institutes of Health, Frederick, MD, USA Correspondence to: Philip S. Low, email: // Keywords : folate receptor, folate receptor beta, activated macrophage, tumor associated macrophage Received : February 10, 2015 Accepted : March 03, 2015 Published : March 30, 2015 Abstract Over-expression of folate receptor alpha on cancer cells has been frequently exploited for delivery of folate-targeted imaging and therapeutic agents to tumors. Because limited information exists on expression of the beta isoform of the folate receptor in human cancers (FR-β), we have evaluated the immunohistochemical staining pattern of FR-β in 992 tumor sections from 20 different human cancer types using a new anti-human FR-β monoclonal antibody. FR-β expression was shown to be more pronounced in cells within the stroma, primarily macrophages and macrophage-like cells than cancer cells in every cancer type studied. Moreover, FR-β expression in both cancer and stromal cells was found to be statistically more prominent in females than males. A significant positive correlation was also observed between FR-β expression on stromal cells and both the stage of the cancer and the presence of lymph node metastases. Based on these data we conclude FR-β may constitute a good target for specific delivery of therapeutic agents to activated macrophages and that accumulation of FR-β positive macrophages in the stroma could serve as a useful indicator of a tumor’s metastatic potential.
Decentralization and Local Public Goods: Getting the Incentives Right

The paper addresses the nature and locus of appropriate government control in the provision of collective services. It suggests some useful principles |'ur determining organizational structures with the appropriate degree and form of decentralization, which is seen to be an important part of incentive compatibility. In the case of low-income housing, it cites the privatization of sites and services and the devolution of upgrading as two promising models of decentralization.
Approximating Large Frequency Moments with Pick-and-Drop Sampling

Given data stream D = {p 1,p 2,…,p m } of size m of numbers from {1,…, n}, the frequency of i is defined as f i = |{j: p j = i}|. The k-th frequency moment of D is defined as \(F_k = \sum_{i=1}^n f_i^k\). We consider the problem of approximating frequency moments in insertion-only streams for k ≥ 3. For any constant c we show an O(n 1 − 2/k log(n)log(c)(n)) upper bound on the space complexity of the problem. Here log(c)(n) is the iterative log function. Our main technical contribution is a non-uniform sampling method on matrices. We call our method a pick-and-drop sampling; it samples a heavy element (i.e., element i with frequency Ω(F k )) with probability Ω(1/n 1 − 2/k ) and gives approximation \(\tilde{f_i} \ge (1-\epsilon)f_i\). In addition, the estimations never exceed the real values, that is \( \tilde{f_j} \le f_j\) for all j. For constant e, we reduce the space complexity of finding a heavy element to O(n 1 − 2/k log(n)) bits. We apply our method of recursive sketches and resolve the problem with O(n 1 − 2/k log(n)log(c)(n)) bits. We reduce the ratio between the upper and lower bounds from O(log2(n)) to O(log(n)log(c)(n)). Thus, we provide a (roughly) quadratic improvement of the result of Andoni, Krauthgamer and Onak (FOCS 2011).
Profile decompositions for wave equations on hyperbolic space with applications

The goal for this paper is twofold. Our first main objective is to develop Bahouri–Gerard type profile decompositions for waves on hyperbolic space. Recently, such profile decompositions have proved to be a versatile tool in the study of the asymptotic dynamics of solutions to nonlinear wave equations with large energy. With an eye towards further applications, we develop this theory in a fairly general framework, which includes the case of waves on hyperbolic space perturbed by a time-independent potential. Our second objective is to use the profile decomposition to address a specific nonlinear problem, namely the question of global well-posedness and scattering for the defocusing, energy critical, semi-linear wave equation on three-dimensional hyperbolic space, possibly perturbed by a repulsive time-independent potential. Using the concentration compactness/rigidity method introduced by Kenig and Merle, we prove that all finite energy initial data lead to a global evolution that scatters to linear waves as $$t \rightarrow \pm \infty $$ . This proof serves as a blueprint for the arguments in the work [45] by the authors, where we study the asymptotic behavior of large energy equivariant wave maps on the hyperbolic plane.
Hacia dónde va la ciencia política

LJa ciencia politica, segun entendemos actualmente el termino, nacio en Europa Occidental a principios de la decada de 1950. Se podria decir que "renacio", f)ero eso no seria del todo preciso, porque en el siglo xix y hasta la Segunda Guerra Mundial, dicha etiqueta senalo una disciplina cautiva dominada, en gran medida, por los enfoques juridicos o historicos (como en el caso, por ejemplo, de Gaetano Mosca). De este modo, la ciencia politica tuvo un nuevo comienzo y se convirtio en un campo de investigacion por derecho propio mas o menos hace medio siglo. En ese tiempo, yo fui uno de sus fundadores (junto con Stein Rokkan, Juan Linz, Mattei Dogan, Hans Daalder, Eric Allardt, S. N. Eisenstadt y otros. Vease Comparative European Politics: The Story ofa ProJession, editado por H. Daalder, 1997). Soy, por lo tanto, uno de los testigos de lo que los "jovenes turcos" de ese entonces tenian en mente, de como concebimos y promovimos la ciencia politica. Ahora soy un "viejo sabio" y me da gusto reflexionar, unos cincuenta anos despues, respecto a donde ha ido la ciencia politica y si ha seguido el camino correcto, el que yo hubiera deseado y esperado. Asi, preguntar hoy dia hacia donde se ha estado dirigiendo la ciencia politica es tambien preguntar si los nuevos comienzos de la disciplina en Europa Oriental debieron o no seguir el camino andado por nuestro "gran hermano", y me refiero a la ciencia politica americana. A mi tambien me ha absorbido de alguna manera nuestro gran hermano (ciertamente, benevolo y bien intencionado) pues tengo unos treinta anos de dar clases en Estados Unidos. Permitaseme anadir que yo me he beneficiado bastante de mi contacto con Esta-
Spinodal Decomposition and Coarsening Fronts in the Cahn–Hilliard Equation

We study spinodal decomposition and coarsening when initiated by localized disturbances in the Cahn–Hilliard equation. Spatio-temporal dynamics are governed by multi-stage invasion fronts. The first front invades a spinodal unstable equilibrium and creates a spatially periodic unstable pattern. Secondary fronts invade this unstable pattern and create a coarser pattern in the wake. We give linear predictions for speeds and wavenumbers in this process and show existence of corresponding nonlinear fronts. The existence proof is based on Conley index theory, a priori estimates, and Galerkin approximations. We also compare our results and predictions with direct numerical simulations and report on some interesting bifurcations.
The Household Enterprise Sector in Tanzania : Why It Matters and Who Cares

The household enterprise sector has a significant role in the Tanzanian economy. It employs a larger share of the urban labor force than wage employment, and is increasingly seen as an alternative to agriculture as a source of additional income for rural and urban households. The sector is uniquely placed within the informal sector, where it represents both conditions of informal employment and informal enterprise. This paper presents a case study on Tanzania using a mixed approach by combining both quantitative and qualitative analysis to examine the important role of household enterprises in the labor force of Tanzania, and to identify key factors that influence their productivity. Household enterprise owners are similar to typical labor force participants although primary education appears to be the minimum qualification for household enterprise operators to be successful. Access to location matters -- good, secure location in a marketplace or industrial cluster raises earnings - and access to transport and electricity is found to have a significant effect on earnings as well. In large urban areas, the biggest constraint faced by household enterprises is the lack of access to secure workspace to run the small business. Although lack of credit is a problem across all enterprises in Tanzania, household enterprises are more vulnerable because they are largely left out of the financial sector either as savers or borrowers. Although HEs are part of the livelihood strategies of over half of households in Tanzania, they are ignored in the current development policy frameworks, which emphasize formalization, not productivity. Tanzania has a large number of programs and projects for informal enterprises, but there is no set of policies and program interventions targeted at the household enterprise sector. This gap exacerbates the vulnerability of household enterprises, and reduces their productivity.
Building countercyclical fiscal policies in Latin America : the international experience

This paper reviews the international experience of developed and underdeveloped economies in reducing the pro-cyclicality and deficit bias of fiscal policies and promoting the adoption of effective countercyclical fiscal policy actions. The paper draws lessons and best international practices for building fiscal policy frameworks and adopting feasible countercyclical fiscal policies in Latin America. The authors review the main arguments regarding the proper role and limitations of countercyclical fiscal policies, and offer an evaluation of the international evidence demonstrating the typical pro-cyclicality and deficit bias of fiscal policy. The paper analyzes the international experience with fiscal frameworks, budgetary rules, and other mechanisms for implementing countercyclical fiscal policies, and describes the necessary preconditions for building a stable and effective countercyclical fiscal policy framework in Latin America. The authors review the international best practices for establishing a reliable and effective countercyclical fiscal policy in the region.
Global Clusters of Innovation

Can innovation and entrepreneurship stimulate economic growth in diverse communities, or is it only effective in a few unique places like Silicon Valley? This article identifies the salient components, behaviors, and linkages that characterize Silicon Valley and explores how these characteristics apply in a diverse selection of economic communities in Europe, Asia, and Latin America. It focuses on the role institutions—such as governments, universities, major corporations, and NGOs—play in shaping such communities. It provides insights for government policy makers on how to enhance their region's innovation potential, and offers strategies for entrepreneurs and venture investors as to how to leverage the benefits of clusters of innovation, wherever one is located.
Stabilization of Sn2+ in K10Sn3(P2Se6)4 and Cs2SnP2Se6 derived from a basic flux.

K10Sn3(P2Se6)4 and Cs2SnP2Se6 stabilize the lower oxidation state of Sn2+. K10Sn3(P2Se6)4 crystallizes in the trigonal space group R3 with a = b = 24.1184(7) A and c = 7.6482(2) A at 100 K. Cs2SnP2Se6 crystallizes in P21/c with a = 10.1160(4) A, b = 12.7867(5) A, c = 11.0828(5) A, and β = 94.463(3)° at 100(2) K. Electronic absorption spectra revealed band gaps of 1.82 eV for K10Sn3(P2Se6)4 and 2.06 eV for Cs2SnP2Se6. Solid-state magic-angle-spinning 31P NMR, UV−vis, Raman, and IR spectroscopy and thermal analysis studies of the compounds are reported.
GOODS 850-5: A z > 4 Galaxy Discovered in the Submillimeter?*

We report an SMA interferometric identification of a bright submillimeter source, GOODS 850-5. This source is one of the brightest 850 μm sources in the GOODS-N but is extremely faint at all other wavelengths. It is not detected in the GOODS HST ACS images and only shows a weak 2 σ signal at 1.4 GHz. It is detected in the Spitzer IRAC bands and the MIPS 24 μm band, however, with very low fluxes. We present evidence in the radio, submillimeter, mid-IR, near-IR, and optical that suggest GOODS 850-5 may be a z > 4 galaxy.