bluuebunny/crossref_metadata_2025 huggingface dataset:
DETECTING SERIES PERIODICITY WITH HORIZONTAL VISIBILITY GRAPHS
Authors: NUÑEZ ANGEL , LACASA LUCAS , VALERO EUSEBIO , GÓMEZ JOSE PATRICIO , LUQUE BARTOLO
Published: August 2012

The horizontal visibility algorithm was recently introduced as a mapping between time series and networks. The challenge lies in characterizing the structure of time series (and the processes that generated those series) using the powerful tools of graph theory. Recent works have shown that the visibility graphs inherit several degrees of correlations from their associated series, and therefore such graph theoretical characterization is in principle possible. However, both the mathematical grounding of this promising theory and its applications are in its infancy. Following this line, here we address the question of detecting hidden periodicity in series polluted with a certain amount of noise. We first put forward some generic properties of horizontal visibility graphs which allow us to define a (graph theoretical) noise reduction filter. Accordingly, we evaluate its performance for the task of calculating the period of noisy periodic signals, and compare our results with standard time domain (autocorrelation) methods. Finally, potentials, limitations and applications are discussed.
PACEMAKERS IN A CAYLEY TREE OF KURAMOTO OSCILLATORS
Authors: GLEISER PABLO M. , PRIGNANO LUCE , PÉREZ-VICENTE CONRAD J. , DÍAZ-GUILERA ALBERT
Published: August 2012

In this work, we study a system of Kuramoto oscillators with identical frequencies in a Cayley tree. Heterogeneity in the frequency distribution is introduced in the root of the tree, allowing for analytical calculations of the phase evolution. In this work, we study a system of Kuramoto oscillators with identical frequencies in a Cayley tree. Heterogeneity in the frequency distribution is introduced in the root of the tree, allowing for analytical calculations of the phase evolution. This simple case can be regarded as a starting point in order to understand how to extract topological features of the connectivity pattern from the dynamic state of the system, and vice versa, for the general situation of a set of phase oscillators located on a tree-like network.
EXPLORING THE KIBBLE–ZUREK MECHANISM IN A SECONDARY BIFURCATION
Authors: MIRANDA M. A. , BURGUETE J. , GONZÁLEZ-VIÑAS W. , MANCINI H.
Published: August 2012

We present new experimental results on the quenching dynamics of an extended thermo-convective system (a network array of approximately 100 convective oscillators) going through a secondary subcritical bifurcation. We characterize a dynamical phase transition through the nature of the domain walls (1D-fronts) that connect the basic multicellular pattern with the new oscillating one. Two different mechanisms of the relaxing dynamics at the threshold are characterized depending on the crossing rate [Formula: see text] of the quenched transition. From the analysis of fronts, we show that these mechanisms follow different correlation length scales ξ ~ μ-σ. Below a critical value μc, a slow response dynamics yields a spatiotemporal coherent front with weak coupling between oscillators. Above μc, for rapid quenches, defects are trapped at the front with a strong coupling between oscillators, similarly to the Kibble–Zurek mechanism in quenched phase transitions. These defects, pinned to the fronts, yield a strong decay of the correlation length.
SADDLE-NODE BIFURCATION CASCADES AND ASSOCIATED TRAVELING WAVES IN WEAKLY COUPLING CML
Authors: SOTELO HERRERA Ma DOLORES , SAN MARTÍN JESÚS , CERRADA LUCÍA
Published: August 2012

In this paper, traveling waves are analytically found in weakly coupling CML, with both global and neighbor couplings. The waves are triggered by the individual dynamics of the oscillators belonging to CML: saddle-node bifurcation cascades. Depending on the wave period different results are obtained, since the larger the period, the larger the collapse produced in the boxes of saddle-node bifurcation cascades.
SYNCHRONIZATION OF MOVING INTEGRATE AND FIRE OSCILLATORS
Authors: PRIGNANO LUCE , SAGARRA OLEGUER , GLEISER PABLO M. , DIAZ-GUILERA ALBERT
Published: August 2012

We present a model of integrate and fire oscillators that move on a plane. The phase of the oscillators evolves linearly in time and when it reaches a threshold value they fire choosing their neighbors according to a certain interaction range. Depending on the velocity of the ballistic motion and the average number of neighbors each oscillator fires to, we identify different regimes shown in a phase diagram. We characterize these regimes by means of novel parameters as the accumulated number of contacted neighbors.
NIL-ARMENDARIZ RINGS AND UPPER NILRADICALS
Authors: JUNG DA WOON , KIM NAM KYUN , LEE YANG , YANG SUNG PIL
Published: August 2012

We continue the study of nil-Armendariz rings, initiated by Antoine, and Armendariz rings. We first examine a kind of ring coproduct constructed by Antoine for which the Armendariz, nil-Armendariz, and weak Armendariz properties are equivalent. Such a ring has an important role in the study of Armendariz ring property and near-related ring properties. We next prove an Antoine's result in relation with the ring coproduct by means of a simpler direct method. In the proof we can observe the concrete shapes of coefficients of zero-dividing polynomials. We next observe the structure of nil-Armendariz rings via the upper nilradicals. It is also shown that a ring R is Armendariz if and only if R is nil-Armendariz if and only if R is weak Armendariz, when R is a von Neumann regular ring.
THE TENEVA GAME
Authors: KAUFFMAN LOUIS H. , LOPES PEDRO
Published: August 2012

For each prime p > 7 we obtain the expression for an upper bound on the minimum number of colors needed to non-trivially color T(2, p), the torus knot of type (2, p), modulo p. This expression is t + 2l -1 where t and l are extracted from the prime p. It is obtained from iterating the so-called Teneva transformations which we introduced in a previous article. With the aid of our estimate we show that the ratio "number of colors needed vs. number of colors available" tends to decrease with increasing modulus p. For instance as of prime 331, the number of colors needed is already one tenth of the number of colors available. Furthermore, we prove that 5 is the minimum number of colors needed to non-trivially color T(2, 11) modulo 11. Finally, as a preview of our future work, we prove that 5 is the minimum number of colors modulo 11 for two rational knots with determinant 11.
QUASI-CLASSICAL TRAJECTORY STUDY OF THE REACTION PROBABILITY AND CROSS SECTION OF THE REACTION LiH + H
Authors: WANG YULIANG , ZHANG JINCHUN , TIAN BAOGUO , WANG KUN , LIANG XIAORUI , ZHOU MINGYU
Published: August 2012

Based on the new accurate potential energy surface of the ground state of LiH2 system. Quasi-classical trajectory (QCT) calculations were carried out for the reaction LiH + H . The reaction probability of the title reaction for J = 0 has been calculated. The reaction cross sections were calculated as functions of the collision energy in the range 0.1–2.5 eV. The results were found to be well consistent with the previous real wave packet (RWP) and QCT results.
SEARCHING FOR NEW MEMBERS OF C70 HOMOFULLERENES BY FIRST-PRINCIPLES COMPUTATIONS: BENT'S RULE AT WORK ON C70 SURFACE
Authors: FENG JIACHENG , LI FENGYU , JIN PENG , LIAO YUNLONG , CHEN ZHONGFANG
Published: August 2012

We carried out systematic density functional theory computations to search for new members of C70 homofullerenes inspired by the Bent's rule. By substituting CH2 by CF2 , we identified five experimentally accessible C70 homofullerenes, among which one member has different bonding character as its CH2 counterpart (where the closed three-membered ring is formed by CH2 addition). This unique C70 homofullerene is expected to be synthesized very smoothly using the standard solution phase chemistry, due to its high thermodynamic stability and the rather high local reactivity of the carbon bond attached to the CF2 addend.
QUANTUM WAVE-PACKET EXPLORATION OF ISOLATED ULTRA-SHORT ATTOSECOND PULSE GENERATION BY A MODIFIED THREE-COLOR LASER FIELD SCHEME
Authors: WANG YUNHUI , WU HAIPING , YU CHAO , SHI QI , DENG KAIMING , LU RUIFENG
Published: August 2012

By numerically solving the three dimensional time-dependent Schrödinger equation, we explore the high-order harmonic and attosecond pulse generation of He atoms exposed to a special three-color field. An ultrabroad supercontinuum with a bandwidth of 887 eV has been attained, supporting an isolated 4 as pulse straightforwardly by Fourier transforming. Utilizing available intense infrared femtosecond laser resource within the nonrelativistic regime, the produced laser pulse is near to zeptosecond region. Remarkably, the harmonic conversion efficiency is enhanced in terms of the double-plateau structure of the harmonic spectra, yielding high-intensity attosecond pulses with alternative plateau.
Decrease in Ozone Density of Atmospheric Surface-Discharge Plasma Source
Authors: Kobayashi Hiroyuki , Tandou Takumi , Nagaishi Hideyuki , Suzuki Keizo , Negishi Nobuyuki
Published: August 2012

A surface-discharge plasma source based on dielectric barrier discharge (DBD) has been developed for use in sterilization and cleaning. In these processes, ozone-generation ability is one of the key factors in regard to atmospheric plasma sources. However, it was observed that ozone density decreased during plasma discharge. It is known that an increase in gas temperature decreases the ozone density; thus, the gas temperature in plasma was measured from the rotational temperature of nitrogen molecules. It was confirmed that the gas temperature increases in the case that the ozone density decreases. A dielectric-surface temperature of the plasma source was also measured and its behavior agreed with that of the gas temperature since the thickness of the plasma was small. It is thus confirmed that cooling the dielectric surface of the plasma source is important to increase the ozone density in a surface-discharge plasma source.
Study on the Distribution Control of Etching Rate and Critical Dimensions in Microwave Electron Cyclotron Resonance Plasmas for the Next Generation 450 mm Wafer Processing
Authors: Maeda Kenji , Obama Shinji , Tamura Hitoshi , Miya Go , Izawa Masaru
Published: August 2012

A newly designed microwave electron cyclotron resonance (ECR) plasma etching reactor has been developed for 450 mm wafer processing. The etching rates of polycrystalline silicon (poly-Si) and SiO2across the wafer were evaluated as a function of ECR position. Two-dimensional (radial and vertical) distributions of the ion flux in the reactor were also investigated using a movable single probe system. A ring-shaped region of high-density plasma along the ECR plane was observed. This reveals the mechanism that the etching-rate distribution could be controlled by the ECR position. As a result, a polycrystalline silicon etching rate uniformity of 1.5% across a wafer was successfully obtained. Furthermore, the uniformity control of critical dimensions (CDs) based on wafer temperature was also investigated, and CD uniformity below 3 nm across the wafer was obtained in the optimum temperature distribution.
Surface Modification of Plasma Polymer Thin Films for DNA Fixation by Atmospheric Pressure Plasma Treatment
Authors: Cho Sang-Jin , Nam Sang-Hun , Kim Hyung Jin , Hong Byungyou , Boo Jin-Hyo
Published: August 2012

The atmospheric pressure plasma treatment on plasma polymer thin films was investigated to control the immobilization of DNA alignment. The amine groups of aminopropyltriethoxysilane have been generally used for the fixation of DNA on the substrate. However, it is easily influenced by humidity, and so it is hard to control precisely the formation of the self-assembled monolayer. The plasma polymer thin films with the atmospheric pressure plasma treatment are expected to be hardly influenced by humidity. Moreover, the densities of the amine groups are expected to be controlled by the treatment. In this work, organic and organic-inorganic hybrid plasma polymer thin films were formed on Si(100) by plasma enhanced chemical vapor deposition using methylcyclohexane and tetraethylorthosilane (TEOS), and the amine groups were formed on the surfaces by N2 atmospheric pressure plasma treatment. Fourier-transform infrared absorption spectroscopy showed that the amine groups were increased with the treatment. The surface densities of the amine groups were obtained from averaged extinction coefficients of UV–visible absorption spectra. DNA fixation was successfully performed with a tilting method for aligning well stretched DNAs on the surfaces, through optimization of the surface condition in the treatment.
Compact Optical Module of Homodyne Detection
Authors: Mikami Hideharu , Kurokawa Takahiro , Watanabe Koichi
Published: August 2012

Homodyne detection is a detection technique that significantly amplifies optical signals. It is useful for the readout of multilayer optical discs, where the signal level is quite low. The improvement of optical disc readout signal quality by homodyne detection has been demonstrated experimentally. However, homodyne detection requires a complicated optical system, which causes large-scale implementation and high cost, which prevents practical use of the technique in optical disc systems. In this report, we demonstrated compact implementation of homodyne detection. We proposed and assembled two types of optical module for homodyne detection. The sizes of the modules were 10×30 and 10×40 mm2, which were comparable to that of the current optical pickup. Jitter of the attenuated Blu-ray DiscTM recordable (BD-R) readout signals was improved from 15 to 7.8% by applying one of the modules.
Robust Adjacent Track Servo System with Linear Positioning Method
Authors: Urakawa Yoshiyuki , Deoka Yoshihiko , Suzuki Yuichi , Mukasa Tomoharu , Horigome Junichi
Published: August 2012

A multilayer disk without a guide groove can be a large-capacity and price-competitive optical disk. We propose a novel tracking servo system that is robust and accurate for disks without grooves. We use only one reference layer for which the linear positioning method is employed, which enables us to obtain tracking servo information over the whole disk radius. We also use an adjacent track servo system so as not to overwrite the previous track. We confirm the stability and performance of the system with a simulation.
High Precision Tracking Control based on Pseudo-Inverse Feedforward Control System for Next-Generation Optical Disks
Authors: Ogata Tokoku , Nakazaki Tatsuya , Sakimura Naohide , Ohishi Kiyoshi , Miyazaki Toshimasa , Koide Daiichi , Tokumaru Haruki , Takano Yoshimichi
Published: August 2012

Optical disk drive systems must realize high-precision tracking control. For this purpose, we have already proposed a tracking control system that is composed of a high gain servo controller (HGSC) and a perfect tracking controller (PTC). The conventional feedforward tracking control system adequately suppresses the tracking error caused by track eccentricity. However, the PTC system in the conventional system is complicated. Therefore, the PTC system embedded on a digital signal processor (DSP) cannot realize fast sampling time and the conventional system has a speedup limitation in the optical disk tracking control system. Hence, in this paper, we propose a new high-speed and high-precision feedforward tracking control system that uses a pseudo-inverse matrix. The proposed system consists of the pseudo-inverse feedforward control (P-IFFC). The proposed system realizes simple and quick execution in a digital signal processor software servo. Our experimental results confirm that the proposed system effectively suppresses the tracking error under a condition of the 7200 rpm disk rotation speed of DVD+R. In addition, the conventional systems and the proposed system with a pseudo-inverse matrix are compared in terms of processing time and tracking error.
A Simple Decoding Scheme for a Balanced 6/8 Modulation Code
Authors: Kim Gukhui , Lee Jaejin
Published: August 2012

Two-dimensional (2D) inter-symbol interference (ISI) and inter-page interference (IPI) are major concerns of holographic data storage (HDS). These problems can be mitigated by modulation code. A 6/8 balanced code is one of the modulation codes that has a 1:1 ratio of symbol “1” and symbol “0”. It avoids the IPI and has a low-pass filtering effect to reduce the ISI. However, the soft-decision decoding for a 6/8 balanced code needs many multiplications to calculate the Euclidean distances, making the circuit complicated. Hard-decision decoding is much simpler but does not perform as well as soft-decision decoding. Therefore, we propose a simple decoding scheme for a 6/8 balanced code which uses hard-decision decoding but performs almost as well as soft-decision decoding.
Sequential Two-Dimensional Partial Response Maximum Likelihood Detection Scheme with Constant-Weight Constraint Code for Holographic Data Storage Systems
Authors: Kong Gyuyeol , Choi Sooyong
Published: August 2012

A sequential two-dimensional (2D) partial response maximum likelihood (PRML) detection scheme for holographic data storage (HDS) systems is proposed. We use two complexity reduction schemes, a reduced-state trellis and a constant-weight (CW) constraint. In the reduced-state trellis, the limited candidate bits surrounding the target bit are considered for the 2D PRML detector. In the CW constraint, the trellis transitions that violate the CW condition that each code-word block has only one white bit are eliminated. However, the 2D PRML detector using the complexity reduction schemes, which operates on 47 states and 169 branches, has performance degradation. To overcome performance degradation, a sequential detection algorithm uses the estimated a priori probability. By the sequential procedure, we mitigate 2D intersymbol interference with an enhanced reliability of the branch metric. Simulation results show that the proposed 2D PRML detection scheme yields about 3 dB gains over the one-dimensional PRML detection scheme.
Two-Dimensional Equalization Using Bilinear Recursive Polynomial Model for Holographic Data Storage Systems
Authors: Kim Taehyung , Kong Gyuyeol , Choi Sooyong
Published: August 2012

In this paper, we propose new two-dimensional (2D) nonlinear equalizers developed on the basis of a bilinear recursive polynomial (BRP) model for holographic data storage (HDS) systems. The 2D BRP equalizer (BRPE) and the 2D BRP decision feedback equalizer (BRPDFE) are proposed. The bit error rate (BER) performances of the proposed schemes are studied in the electrical-noise-dominant channel (ENDC) and the optical-noise-dominant channel (ONDC). The proposed schemes are compared with the conventional adaptive DFE and the partial response maximum likelihood (PRML) detector. The simulation results show that the proposed schemes outperform the adaptive DFE and the PRML detector. In particular, the BRPDFE shows the best BER performance in both the ENDC and the ONDC.
Line Tracking Applied Data Acquisition Method for Holographic Data Storage System
Authors: Lee Jae-Seong , Kim Nakyeong , Lim Sung-Yong , Kim Jang Hyun , Park Kyoung-Su , Park No-Cheol , Yang Hyunseok , Park Young-Pil
Published: August 2012

In a holographic data storage device, data are stored and retrieved as two-dimensional images. These images can be distorted in various ways. Generally, sync marks are used to acquire exact pixel values in a distorted image. However, this inevitably results in some loss of data density. In this research, a virtual detector that follows the rows of an image like a compact disk (CD) track is used to acquire the data pixels in a distorted image without sync marks. The proposed method can compensate for image distortion without any loss of data density. The feasibility of the new technique is demonstrated by simulation. The procedure is also evaluated on the basis of signal-to-noise ratio and bit error ratio.
Error Correcting Capable 2/4 Modulation Code Using Trellis Coded Modulation in Holographic Data Storage
Authors: Kim Yongok , Kong Gyuyeol , Choi Sooyong
Published: August 2012

An error correcting capable 2/4 modulation code scheme is proposed in holographic data storage (HDS) systems. We adopt trellis coded modulation (TCM) to obtain a good error correcting capability without loss of data rate in the HDS systems. To overcome loss of a data rate caused by a 1/2-rate convolutional code, we extend a 2/4 modulation code set the 3/4 modulation code set as high-order modulation in the proposed scheme. Additionally, we find an optimal mapping method of index numbers to maximize the free distance on the trellis and calculate the free distance according to each constraint length. The simulation results show that the proposed scheme with the same data rate has about 4 dB coding gains compared to the conventional 2/4 modulation coding scheme.
Application of Solid Immersion Lens-Based Near-Field Recording Technology to High-Speed Plasmonic Nanolithography
Authors: Park Kyoung-Su , Kim Taeseob , Lee Won-Sup , Joe Hang-Eun , Min Byung-Kwon , Park Young-Pil , Yang Hyunseok , Kang Sung-Mook , Park No-Cheol
Published: August 2012

In this paper, we proposed a high-speed and high-throughput plasmonic nanolithography technique that uses a fabricated sharp-ridged nanoaperture on a solid immersion lens (SIL) and a precise active nanogap control algorithm. This plasmonic lithography with high throughput can make an optical spot with a diameter of the order of 10 nm and can perform nanopatterning at sub-m/s speed. An optical high-throughput head was designed on a metallic aluminum aperture by optimizing the geometric parameters of a sharp-ridged antenna on the basis of the optical intensity and spot size. Using the evanescent field generated from the SIL, the plasmonic SIL could be maintained below 20 nm above a photoresist-coated Si-wafer and could move at a speed of greater than 200 mm/s without friction; the patterning of lines could be performed under this condition. We achieved patterning with a line width (full-width at half-magnitude, FWHM) of 130 nm.
High-Speed Atomic Force Microscopy
Authors: Ando Toshio , Uchihashi Takayuki , Kodera Noriyuki
Published: August 2012

The technology of high-speed atomic force microscopy (HS-AFM) has reached maturity. HS-AFM enables us to directly visualize the structure and dynamics of biological molecules in physiological solutions at subsecond to sub-100 ms temporal resolution. By this microscopy, dynamically acting molecules such as myosin V walking on an actin filament and bacteriorhodopsin in response to light are successfully visualized. High-resolution molecular movies reveal the dynamic behavior of molecules in action in great detail. Inferences no longer have to be made from static snapshots of molecular structures and from the dynamic behavior of optical markers attached to biomolecules. In this review, we first describe theoretical considerations for the highest possible imaging rate, then summarize techniques involved in HS-AFM and highlight recent imaging studies. Finally, we briefly discuss future challenges to explore.
On-Chip Cellomics: Constructive Understanding of Multicellular Network Using On-Chip Cellomics Technology
Authors: Yasuda Kenji
Published: August 2012

We have developed methods and systems of analyzing epigenetic information in cells to expand our understanding of how living systems are determined. Because cells are minimum units reflecting epigenetic information, which is considered to map the history of a parallel-processing recurrent network of biochemical reactions, their behaviors cannot be explained by considering only conventional deonucleotide (DNA) information-processing events. The role of epigenetic information on cells, which complements their genetic information, was inferred by comparing predictions from genetic information with cell behaviour observed under conditions chosen to reveal adaptation processes and community effects. A system of analyzing epigenetic information, on-chip cellomics technology, has been developed starting from the twin complementary viewpoints of cell regulation as an “algebraic” system (emphasis on temporal aspects) and as a “geometric” system (emphasis on spatial aspects) exploiting microfabrication technology and a reconstructive approach of cellular systems not only for single cell-based subjects such asEscherichia coliand macrophages but also for cellular networks like the community effect of cardiomyocytes and plasticity in neuronal networks. One of the most important contributions of this study was to be able to reconstruct the concept of a cell regulatory network from the “local” (molecules expressed at certain times and places) to the “global” (the cell as a viable, functioning system). Knowledge of epigenetic information, which we can control and change during cell lives, complements the genetic variety, and these two types of information are indispensable for living organisms. This new knowlege has the potential to be the basis of cell-based biological and medical fields such as those involving cell-based drug screening and the regeneration of organs from stem cells.
Noncontact Atomic Force Microscopy Observation of Fe3O4(001) Surface
Authors: Mizuno Taichi , Hosoi Hirotaka , Subagyo Agus , Oishi Suguru , Ikeuchi Akira , Hiura Satoshi , Sueoka Kazuhisa
Published: August 2012

Fe3O4 is one of the important oxide materials and its surface structure should be well understood to enable application of this material. We report the first noncontact atomic force microscopy (NC-AFM) results for Fe3O4(001) thin films. The observed films were grown homoepitaxially on magnetite thin films substrate. A low-energy electron diffraction pattern shows the well-known (√2×√2)R45° reconstructed structure. The observed minimum step height is 0.21 nm, corresponding to the distance between the same planes. We obtain two types of atomic-scale NC-AFM images. One image shows bright protrusions along the [100] and [010] directions at intervals of 0.84 nm corresponding to a unit cell of the (√2×√2)R45° reconstructed structure. The other image shows a more detailed atomic structure with 0.6 and 0.3 nm corrugations.
Frequency Modulation Atomic Force Microscopy in Ionic Liquid Using Quartz Tuning Fork Sensors
Authors: Ichii Takashi , Fujimura Motohiko , Negami Masahiro , Murase Kuniaki , Sugimura Hiroyuki
Published: August 2012

Frequency modulation atomic force microscopy (FM-AFM) imaging in ionic liquids (ILs) were carried out. A quartz tuning fork sensor with a sharpened tungsten tip was used as a force sensor instead of a Si cantilever. Only the tip apex was immersed in ILs and the quality factor of the sensors was kept more than 100 in spite of the high viscosity of ILs. Atomic-resolution topographic imaging was successfully achieved in an IL as well as in an aqueous solution. In addition, frequency shift versus tip-to-sample distance curves were obtained and the structures of local solvation layers were studied.
Narrow Banking
Authors: Pennacchi George
Published: August 2012

This review discusses the history of narrow banks, reform proposals involving narrow banks, and theory and empirical evidence regarding whether narrow banks should play a more prominent role in the financial system. Prior to the early-twentieth century, US banks tended to be much narrower than they are today. Common modern banking practices, such as maturity transformation and explicit loan commitments, arose only after the creation of the Federal Reserve and the FDIC. My review of theory and empirical evidence finds it largely supportive of narrow bank reforms. Most importantly, a narrow-banking system could have huge advantages in containing moral hazard and reducing the overall risk and required regulation of the financial system.
Valuation of Government Policies and Projects
Authors: Lucas Deborah
Published: August 2012

Governments play a central role in the allocation of capital and risk in the economy. Evaluating the cost to taxpayers of government investments requires an assumption about the government's cost of capital. Governments often take their borrowing rate to be their cost of capital, which implicitly treats the market risk associated with their activities as having no cost to taxpayers. This article reviews the theoretical and practical rationale for treating market risk as a cost to governments, presents an interpretive review of the growing literature that applies the concepts and tools of modern finance to evaluating the costs of government policies and projects, and suggests directions for future research. Examples considered include deposit insurance, Fannie Mae and Freddie Mac, the Federal Reserve's emergency lending facilities, student loans, real infrastructure investments, and public pension plans.
Noncoding Transcription at Enhancers: General Principles and Functional Models
Authors: Natoli Gioacchino , Andrau Jean-Christophe
Published: August 2012

Mammalian genomes are extensively transcribed outside the borders of protein-coding genes. Genome-wide studies recently demonstrated that cis-regulatory genomic elements implicated in transcriptional control, such as enhancers and locus-control regions, represent major sites of extragenic noncoding transcription. Enhancer-templated transcripts provide a quantitatively small contribution to the total amount of cellular nonribosomal RNA; nevertheless, the possibility that enhancer transcription and the resulting enhancer RNAs may, in some cases, have functional roles, rather than represent mere transcriptional noise at accessible genomic regions, is supported by an increasing amount of experimental data. In this article we review the current knowledge on enhancer transcription and its functional implications.
Regulating Sex Work: Heterogeneity in Legal Strategies
Authors: McCarthy Bill , Benoit Cecilia , Jansson Mikael , Kolar Kat
Published: August 2012

In this article, we examine various legal strategies used to regulate the sale and purchase of sexual services. We use three broad categories to structure our discussion: full criminalization, partial decriminalization, and full decriminalization. In each section, we discuss laws directed toward the control of sellers, buyers, and third parties. We focus on legislation and practices at the highest level of aggregation (i.e., the national, state, or provincial level), and due to limited data, we concentrate on high-income countries. We present a critical assessment of each legal approach and conclude with a call for future research on the consequences of different legal strategies for sellers, buyers, and third parties.
Puzzles in Hadronic Physics and Novel Quantum Chromodynamics Phenomenology
Authors: Brodsky Stanley J. , de Téramond Guy , Karliner Marek
Published: August 2012

We review some outstanding puzzles and experimental anomalies in hadron physics that appear to challenge conventional wisdom and, in some cases, the foundations of quantum chromodynamics (QCD). We also discuss possible solutions and propose new tests and experiments that could illuminate the underlying physics and novel phenomenological features of QCD. In some cases, new perspectives for QCD physics have emerged.
Cardiac mitochondrial matrix and respiratory complex protein phosphorylation
Authors: Covian Raul , Balaban Robert S.
Published: August 2012

It has become appreciated over the last several years that protein phosphorylation within the cardiac mitochondrial matrix and respiratory complexes is extensive. Given the importance of oxidative phosphorylation and the balance of energy metabolism in the heart, the potential regulatory effect of these classical signaling events on mitochondrial function is of interest. However, the functional impact of protein phosphorylation and the kinase/phosphatase system responsible for it are relatively unknown. Exceptions include the well-characterized pyruvate dehydrogenase and branched chain α-ketoacid dehydrogenase regulatory system. The first task of this review is to update the current status of protein phosphorylation detection primarily in the matrix and evaluate evidence linking these events with enzymatic function or protein processing. To manage the scope of this effort, we have focused on the pathways involved in energy metabolism. The high sensitivity of modern methods of detecting protein phosphorylation and the low specificity of many kinases suggests that detection of protein phosphorylation sites without information on the mole fraction of phosphorylation is difficult to interpret, especially in metabolic enzymes, and is likely irrelevant to function. However, several systems including protein translocation, adenine nucleotide translocase, cytochrome c, and complex IV protein phosphorylation have been well correlated with enzymatic function along with the classical dehydrogenase systems. The second task is to review the current understanding of the kinase/phosphatase system within the matrix. Though it is clear that protein phosphorylation occurs within the matrix, based on32P incorporation and quantitative mass spectrometry measures, the kinase/phosphatase system responsible for this process is ill-defined. An argument is presented that remnants of the much more labile bacterial protein phosphoryl transfer system may be present in the matrix and that the evaluation of this possibility will require the application of approaches developed for bacterial cell signaling to the mitochondria.
Microparticle release in remote ischemic conditioning mechanism
Authors: Jeanneteau Julien , Hibert Pierre , Martinez Maria Carmen , Tual-Chalot Simon , Tamareille Sophie , Furber Alain , Andriantsitohaina Ramaroson , Prunier Fabrice
Published: August 2012

Remote ischemic conditioning (RCond) induced by short periods of ischemia and reperfusion of an organ or tissue before myocardial reperfusion is an attractive strategy of cardioprotection in the context of acute myocardial infarction. Nonetheless, its mechanism remains unknown. A humoral factor appears to be involved, although its identity is currently unknown. We hypothesized that the circulating microparticles (MPs) are the link between the remote tissue and the heart. MPs from rats and healthy humans undergoing RCond were characterized. In rats, RCond was induced by 10 min of limb ischemia. In humans, RCond was induced by three cycles of 5-min inflation and 5-min deflation of a blood-pressure cuff. In the second part of the study, rats underwent 40 min myocardial ischemia followed by 2 h reperfusion. Infarct size was measured and compared among three groups of rats: 1) myocardial infarction alone (MI) ( n = 6); 2) MI + RCond started 20 min after coronary ligation ( n = 6); and 3) MI + injection of RCond-derived rat MPs (MI + MPs) ( n = 5). MPs from endothelial cells (CD54+ and CD146+ for rats and humans, respectively) and procoagulant MPs (Annexin V+) markedly increased after RCond, both in rats and humans. RCond reduced infarct size (24.4 ± 5.9% in MI + RCond vs. 54.6 ± 4.7% in MI alone; P < 0.01). Infarct size did not decrease in MI + MPs compared with MI alone (50.2 ± 6.4% vs. 54.6 ± 4.7%, not significantly different). RCond increased endothelium-derived and procoagulant MPs in both rats and humans. However, MP release did not appear to be a biological vector of RCond in our model.
miRNAs in ESC differentiation
Authors: Berardi Emanuele , Pues Matthias , Thorrez Lieven , Sampaolesi Maurilio
Published: August 2012

MicroRNAs (miRNAs) are small sequences of noncoding RNAs that regulate gene expression by two basic processes: direct degradation of mRNA and translation inhibition. miRNAs are key molecules in gene regulation for embryonic stem cells, since they are able to repress target pluripotent mRNA genes, including Oct4, Sox2, and Nanog. miRNAs are unlike other small noncoding RNAs in their biogenesis, since they derive from precursors that fold back to form a distinctive hairpin structure, whereas other classes of small RNAs are formed from longer hairpins or bimolecular RNA duplexes (siRNAs) or precursors without double-stranded character (piRNAs). An increasing amount of evidence suggests that miRNAs may have a critical role in the maintenance of the pluripotent cell state and in the regulation of early mammalian development. This review gives an overview of the current state of the art of miRNA expression and regulation in embryonic stem cell differentiation. Current insights on controlling stem cell fate toward mesodermal, endodermal and ectodermal differentiation, and cell reprogramming are also highlighted.
Sites of action of ghrelin receptor ligands in cardiovascular control
Authors: Callaghan Brid , Hunne Billie , Hirayama Haruko , Sartor Daniela M. , Nguyen Trung V. , Abogadie Fe C. , Ferens Dorota , McIntyre Peter , Ban Kung , Baell Jonathan , Furness John B. , Brock James A.
Published: August 2012

Circulating ghrelin reduces blood pressure, but the mechanism for this action is unknown. This study investigated whether ghrelin has direct vasodilator effects mediated through the growth hormone secretagogue receptor 1a (GHSR1a) and whether ghrelin reduces sympathetic nerve activity. Mice expressing enhanced green fluorescent protein under control of the promoter for growth hormone secretagogue receptor (GHSR) and RT-PCR were used to locate sites of receptor expression. Effects of ghrelin and the nonpeptide GHSR1a agonist capromorelin on rat arteries and on transmission in sympathetic ganglia were measured in vitro. In addition, rat blood pressure and sympathetic nerve activity responses to ghrelin were determined in vivo. In reporter mice, expression of GHSR was revealed at sites where it has been previously demonstrated (hypothalamic neurons, renal tubules, sympathetic preganglionic neurons) but not in any artery studied, including mesenteric, cerebral, and coronary arteries. In rat, RT-PCR detected GHSR1a mRNA expression in spinal cord and kidney but not in the aorta or in mesenteric arteries. Moreover, the aorta and mesenteric arteries from rats were not dilated by ghrelin or capromorelin at concentrations >100 times their EC50 determined in cells transfected with human or rat GHSR1a. These agonists did not affect transmission from preganglionic sympathetic neurons that express GHSR1a. Intravenous application of ghrelin lowered blood pressure and decreased splanchnic nerve activity. It is concluded that the blood pressure reduction to ghrelin occurs concomitantly with a decrease in sympathetic nerve activity and is not caused by direct actions on blood vessels or by inhibition of transmission in sympathetic ganglia.
PACAP causes PAC1/VPAC2 receptor mediated hypertension and sympathoexcitation in normal and hypertensive rats
Authors: Farnham M. M. J. , Lung M. S. Y. , Tallapragada V. J. , Pilowsky P. M.
Published: August 2012

Pituitary adenylate cyclase-activating polypeptide (PACAP) is an excitatory neuropeptide that plays an important role in hypertension and stress responses. PACAP acts at three G protein-coupled receptors [PACAP type 1 receptor (PAC1) and vasoactive intestinal peptide receptor types 1 and 2 (VPAC1 and VPAC2)] and is localized to sites involved in cardiovascular control, most significantly the rostral ventrolateral medulla (RVLM). The RVLM is crucial for the tonic and reflex control of efferent sympathetic activity. Increases in sympathetic activity are observed in most types of hypertension and heart failure. PACAP delivered intrathecally also causes massive sympathoexcitation. We aimed to determine the presence and abundance of the three PACAP receptors in the RVLM, the role, in vivo, of PACAP in the RVLM on tonic and reflex cardiovascular control, and the contribution of PACAP to hypertension in the spontaneously hypertensive rat (SHR). Data were obtained using quantitative PCR and microinjection of PACAP and its antagonist, PACAP(6–38), into the RVLM of anesthetized artificially ventilated normotensive rats or SHRs. All three receptors were present in the RVLM. PACAP microinjection into the RVLM caused sustained sympathoexcitation and tachycardia with a transient hypertension but did not affect homeostatic reflexes. The responses were partially mediated through PAC1/VPAC2 receptors since the effect of PACAP was attenuated (∼50%) by PACAP(6–38). PACAP was not tonically active in the RVLM in this preparation because PACAP(6–38) on its own had no inhibitory effect. PACAP has long-lasting cardiovascular effects, but altered PACAP signaling within the RVLM is not a cause of hypertension in the SHR.
Hypothermia-induced spatially discordant action potential duration alternans and arrhythmogenesis in nonhibernating versus hibernating mammals
Authors: Egorov Yuriy V. , Glukhov Alexey V. , Efimov Igor R. , Rosenshtraukh Leonid V.
Published: August 2012

The heart of hibernating species is resistant to lethal ventricular fibrillation (VF) induced by hypothermia. Spatially discordant (SDA) cardiac alternans is a promising predictor of VF, yet its role in the mechanism of hypothermic arrhythmogenesis in both nonhibernating and hibernating mammals remains unclear. We optically mapped the posterior epicardial surface of Langendorff-perfused hearts of winter hibernating (WH, n = 13), interbout arousal (IBA; n = 4), and summer active (SA, n = 6) ground squirrels (GSs; Spermophilus undulatus) and rabbits ( n = 10). Action potential duration (APD) and conduction velocity (CV) dynamic restitution and alternans were determined at 37 to 17°C. In all animals, hypothermia induced heterogeneous APD prolongation, enhanced APD dispersion, and slowed CV. In all groups, hypothermia promoted the formation of APD alternans, which was predominantly spatially concordant in GSs and SDA in rabbits (SD of APD dispersion: 4.2 ± 0.4% vs. 2.0 ± 0.3% at 37°C and 7.5 ± 1.1% vs. 3.4 ± 0.5% at 17°C, P < 0.001 for rabbits vs. the WH group, respectively). In rabbits, hypothermia significantly increased the magnitude of SDA, which enhanced the ventricular repolarization gradient, caused conduction delays (CV: 3.2 vs. 8.2 cm/s at 17°C in rabbits vs. the WH group), conduction block, and the onset of VF (0% at 37°C vs. 60% at 17°C, P < 0.01). In contrast, no arrhythmia was observed in GS hearts at any temperature. The amplitude of CV alternans was greater in rabbits (5.2 ± 0.4% versus 4.5 ± 0.3% at 37°C and 35.3 ± 4.2% vs. 14.9 ± 1.5% at 17°C in rabbits vs. the WH group, P < 0.001 at 17°C) and correlated with the amplitude of SDA. In conclusion, the mechanism underlying SDA formation during hypothermia is likely associated with CV alternans conditioned by an enhanced dispersion of repolarization. The factors of hibernating species resistance to SDA and VF seem to be the safe and dynamically stable conduction and the low dispersion of repolarization.
Computational approaches to understand cardiac electrophysiology and arrhythmias
Authors: Roberts Byron N. , Yang Pei-Chi , Behrens Steven B. , Moreno Jonathan D. , Clancy Colleen E.
Published: August 2012

Cardiac rhythms arise from electrical activity generated by precisely timed opening and closing of ion channels in individual cardiac myocytes. These impulses spread throughout the cardiac muscle to manifest as electrical waves in the whole heart. Regularity of electrical waves is critically important since they signal the heart muscle to contract, driving the primary function of the heart to act as a pump and deliver blood to the brain and vital organs. When electrical activity goes awry during a cardiac arrhythmia, the pump does not function, the brain does not receive oxygenated blood, and death ensues. For more than 50 years, mathematically based models of cardiac electrical activity have been used to improve understanding of basic mechanisms of normal and abnormal cardiac electrical function. Computer-based modeling approaches to understand cardiac activity are uniquely helpful because they allow for distillation of complex emergent behaviors into the key contributing components underlying them. Here we review the latest advances and novel concepts in the field as they relate to understanding the complex interplay between electrical, mechanical, structural, and genetic mechanisms during arrhythmia development at the level of ion channels, cells, and tissues. We also discuss the latest computational approaches to guiding arrhythmia therapy.
Intrinsic increase in lymphangion muscle contractility in response to elevated afterload
Authors: Davis Michael J. , Scallan Joshua P. , Wolpers John H. , Muthuchamy Mariappan , Gashev Anatoliy A. , Zawieja David C.
Published: August 2012

Collecting lymphatic vessels share functional and biochemical characteristics with cardiac muscle; thus, we hypothesized that the lymphatic vessel pump would exhibit behavior analogous to homeometric regulation of the cardiac pump in its adaptation to elevated afterload, i.e., an increase in contractility. Single lymphangions containing two valves were isolated from the rat mesenteric microcirculation, cannulated, and pressurized for in vitro study. Pressures at either end of the lymphangion [input pressure (Pin), preload; output pressure (Pout), afterload] were set by a servo controller. Intralymphangion pressure (PL) was measured using a servo-null micropipette while internal diameter and valve positions were monitored using video methods. The responses to step- and ramp-wise increases in Pout (at low, constant Pin) were determined. PL and diameter data recorded during single contraction cycles were used to generate pressure-volume (P-V) relationships for the subsequent analysis of lymphangion pump behavior. Ramp-wise Pout elevation led to progressive vessel constriction, a rise in end-systolic diameter, and an increase in contraction frequency. Step-wise Pout elevation produced initial vessel distention followed by time-dependent declines in end-systolic and end-diastolic diameters. Significantly, a 30% leftward shift in the end-systolic P-V relationship accompanied an 84% increase in dP/d t after a step increase in Pout, consistent with an increase in contractility. Calculations of stroke work from the P-V loop area revealed that robust pumps produced net positive work to expel fluid throughout the entire afterload range, whereas weaker pumps exhibited progressively more negative work as gradual afterload elevation led to pump failure. We conclude that lymphatic muscle adapts to output pressure elevation with an intrinsic increase in contractility and that this compensatory mechanism facilitates the maintenance of lymph pump output in the face of edemagenic and/or gravitational loads.