bluuebunny/crossref_metadata_2025 huggingface dataset:
Parisian ruin of self-similar Gaussian risk processes
Authors: Dębicki Krzysztof , Hashorva Enkelejd , Ji Lanpeng
Published: March 2016

In this paper we derive the exact asymptotics of the probability of Parisian ruin for self-similar Gaussian risk processes. Additionally, we obtain the normal approximation of the Parisian ruin time and derive an asymptotic relation between the Parisian and the classical ruin times.
Volume and duration of losses in finite buffer fluid queues
Authors: Guillemin Fabrice , Sericola Bruno
Published: March 2016

We study congestion periods in a finite fluid buffer when the net input rate depends upon a recurrent Markov process; congestion occurs when the buffer content is equal to the buffer capacity. Similarly to O'Reilly and Palmowski (2013), we consider the duration of congestion periods as well as the associated volume of lost information. While these quantities are characterized by their Laplace transforms in that paper, we presently derive their distributions in a typical stationary busy period of the buffer. Our goal is to compute the exact expression of the loss probability in the system, which is usually approximated by the probability that the occupancy of the infinite buffer is greater than the buffer capacity under consideration. Moreover, by using general results of the theory of Markovian arrival processes, we show that the duration of congestion and the volume of lost information have phase-type distributions.
Sharp bounds for exponential approximations under a hazard rate upper bound
Authors: Brown Mark
Published: March 2016

Consider an absolutely continuous distribution on [0, ∞) with finite meanμand hazard rate functionh(t) ≤bfor allt. Forbμclose to 1, we would expectFto be approximately exponential. In this paper we obtain sharp bounds for the Kolmogorov distance betweenFand an exponential distribution with meanμ, as well as betweenFand an exponential distribution with failure rateb. We apply these bounds to several examples. Applications are presented to geometric convolutions, birth and death processes, first-passage times, and to decreasing mean residual life distributions.
The limiting failure rate for a convolution of life distributions
Authors: Block Henry W. , Langberg Naftali A. , Savits Thomas H.
Published: March 2016

In this paper we investigate the limiting behavior of the failure rate for the convolution of two or more life distributions. In a previous paper on mixtures, Block, Mi and Savits (1993) showed that the failure rate behaves like the limiting behavior of the strongest component. We show a similar result here for convolutions. We also show by example that unlike a mixture population, the ultimate direction of monotonicity does not necessarily follow that of the strongest component.
Editorial: Mathematical modelling of infectious diseases
Authors: FENTON ANDY
Published: March 2016

The field of disease ecology – the study of the spread and impact of parasites and pathogens within their host populations and communities – has a long history of using mathematical models. Dating back over 100 years, researchers have used mathematics to describe the spread of disease-causing agents, understand the relationship between host density and transmission and plan control strategies. The use of mathematical modelling in disease ecology exploded in the late 1970s and early 1980s through the work of Anderson and May (Anderson and May, 1978, 1981, 1992; May and Anderson, 1978), who developed the fundamental frameworks for studying microparasite (e.g. viruses, bacteria and protozoa) and macroparasite (e.g. helminth) dynamics, emphasizing the importance of understanding features such as the parasite's basic reproduction number (R0) and critical community size that form the basis of disease ecology research to this day. Since the initial models of disease population dynamics, which primarily focused on human diseases, theoretical disease research has expanded hugely to encompass livestock and wildlife disease systems, and also to explore evolutionary questions such as the evolution of parasite virulence or drug resistance. More recently there have been efforts to broaden the field still further, to move beyond the standard ‘one-host-one-parasite’ paradigm of the original models, to incorporate many aspects of complexity of natural systems, including multiple potential host species and interactions among multiple parasite species.
Research and Evaluations of the Health Aspects of Disasters, Part VIII: Risk, Risk Reduction, Risk Management, and Capacity Building
Authors: Birnbaum Marvin L. , Loretti Alessandro , Daily Elaine K. , O’Rourke Ann P.
Published: March 2016

There is a cascade of risks associated with a hazard evolving into a disaster that consists of the risk that: (1) a hazard will produce an event; (2) an event will cause structural damage; (3) structural damage will create functional damages and needs; (4) needs will create an emergency (require use of the local response capacity); and (5) the needs will overwhelm the local response capacity and result in a disaster (ie, the need for outside assistance). Each step along the continuum/cascade can be characterized by its probability of occurrence and the probability of possible consequences of its occurrence, and each risk is dependent upon the preceding occurrence in the progression from a hazard to a disaster. Risk-reduction measures are interventions (actions) that can be implemented to: (1) decrease the risk that a hazard will manifest as an event; (2) decrease the amounts of structural and functional damages that will result from the event; and/or (3) increase the ability to cope with the damage and respond to the needs that result from an event. Capacity building increases the level of resilience by augmenting the absorbing and/or buffering and/or response capacities of a community-at-risk. Risks for some hazards vary by the context in which they exist and by the Societal System(s) involved.

BirnbaumML, LorettiA, DailyEK, O’RourkeAP. Research and evaluations of the health aspects of disasters, part VIII: risk, risk reduction, risk management, and capacity building. Prehosp Disaster Med. 2016;31(3):300–308.
Preparation and Loading Process of Single Crystalline Samples into a Gas Environmental Cell Holder for In Situ Atomic Resolution Scanning Transmission Electron Microscopic Observation
Authors: Straubinger Rainer , Beyer Andreas , Volz Kerstin
Published: March 2016

A reproducible way to transfer a single crystalline sample into a gas environmental cell holder for in situ transmission electron microscopic (TEM) analysis is shown in this study. As in situ holders have only single-tilt capability, it is necessary to prepare the sample precisely along a specific zone axis. This can be achieved by a very accurate focused ion beam lift-out preparation. We show a step-by-step procedure to prepare the sample and transfer it into the gas environmental cell. The sample material is a GaP/Ga(NAsP)/GaP multi-quantum well structure on Si. Scanning TEM observations prove that it is possible to achieve atomic resolution at very high temperatures in a nitrogen environment of 100,000 Pa.
Binaries in Globular Clusters
Authors: Mcmillan S. L. W. , Pryor C. , Phinney E. S.
Published: March 2016

Binary stars in a globular cluster (hereafter, GC) may be primordial (i.e. formed along with the cluster), or the result of cluster dynamics. “Dynamical” binaries can result from conservative three-body encounters (e.g. Spitzer, 1987) if a third star can carry away enough kinetic energy to leave two others bound, or from dissipative two-body encounters, if two stars happen to pass within a few stellar radii of one other (Fabian, Pringle, & Rees, 1975). Such non-primordial systems are likely to be found primarily in evolved GC cores, both because conditions are more favorable for making them there, and because of mass segregation. Knowledge of the formation process allows reasonable estimates to be made of their mass and energy distributions. The initial spatial, mass, and energy distributions of primordial binaries, on the other hand, are largely unknown.
Fundamental Parameters of CP Stars
Authors: North P.
Published: March 2016

The quest for accurate fundamental parameters (M, R, Teff log g, v sin i) of CP stars has been a lasting problem ever since the nature and origin of these stars has been discussed. The main reason for the difficulty lies in the anomalous colours of these stars, linked with their abundance anomalies which are responsible for complicated blocking and backwarming effects. In the following, we review the Teff determinations proposed so far, and show how the Hipparcos results improve the radius and log g determinations of nearby Ap stars.
Modelling of the Magnetic Configuration of CP Stars from Polarimetric Observations
Authors: Landolfi M.
Published: March 2016

The observational quantities commonly used to study the magnetic field of CP stars – the mean field modulus and the mean longitudinal field, as well as the ‘mean asymmetry of the longitudinal field’ and the ‘mean quadratic field’ recently introduced by Mathys (1995a,b) – are based either on the Stokes parameter / or on the Stokes parameter V. However, a complete description of polarized radiation requires the knowledge of the full Stokes vector: in other words, we should expect that useful information is also contained in linear polarization (the Stokes parameters Q and U); or rather we should expect the information contained in (Q, U) and in V to be complementary, since linear and circular polarization are basically related to the transverse and the longitudinal component of the magnetic field, respectively.
λBoötis Stars
Authors: Weiss W. W. , Paunzen E.
Published: March 2016

This group of metal poor stars were introduced with the identification of an ‘abnormal’ spectrum for λBoõtis in the famous classification survey of Morgan, Keenan & Kellman (1943) based on a blue sensitive photographic emulsion. More stars were discovered with comparable spectra and with other peculiarities, in particular when the available spectral region was extended to the red and beyond the optical region towards the IR and to the UV.
The Dṛkpakṣasāraṇī: A Sanskrit Version of de la Hire’s Tabulae Astronomicae
Authors: Pingree David
Published: March 2016

In November of 1730 the Portuguese astronomer Pedro da Silva arrived in Jayasiṃha’s court bearing, among other books, a copy of the second edition of Philippe de La Hire’s Tabulae Astro-nomicae, published in Paris in 1727. The choice of this text as the representative of contemporary European astronomy being sent to the Maharaja was apparently due to the fact that de La Hire, finding fault with the Rudolphine Tables, whose alleged errors he attributes to Kepler’s hypotheses, claims: Quamobrem id statui Tabulas meas nulli hypothesi, sed observationibus tantummodò superstruere, nulla cuius vis Systematis habita ratione. This abjuring of adhesion to an “heretical” astronomy must have pleased the Jesuits who chose the book. This aspect of the Tabulae Astronomicae (though in fact de La Hire does adhere to an astronomical hypothesis, the heliocentric) appealed also to Jospeh Dubois, who wrote at the beginning of the Jayapura copy on September 1732: Tabulae Astronomicae in quibus Solis, Lunae, reliquorum planetarum motus ex ipsis observationibus nulla adhibita hypotesi traduntur. This same propaganda explains the title, Drkpaksasâranï, given to the adaption of the Tabulae Astronomicae written in Sanskrit verse by Kevalarama, Jayasimha’s jyotisarãja, in or after 1733 when the new city of Jayapura, to which he refers, began to be occupied, and the astonishing fact that Kevalrarãma nowhere in this work mentions the heliocentric theory though the computations that he prescribes are based upon it.
The Earliest Evidence of the Introduction of Kepler’S Laws to China as is Observed in the Lifa Wenda
Authors: Hashimoto Keizo
Published: March 2016

Recently Catherine Jami and I have found the manuscript of the Lifa wenda Dialogue on Astronomy) by Jean-Francois Foucquet (Fu Shengze , 1665-1741) at British Library. Together with the other, partial, but, otherwise identical, version, which she had located at the Vatican Apostolic Library, the manuscript, especially Book V, Part 1, from the British Library, gives us the detail of how Kepler’s forst and second Laws was introduced into China as early as in the 1710’s. This means that we can go back in the history of the introduction more than two decades earlier than the so far believed date.
Power and Politics in Nineteenth Century Australian Astronomy
Authors: Orchiston Wayne
Published: March 2016

The period 1850-1910 was a “golden age” in Australian astronomy, with the establishment of professional observatories, substantial growth of popular interest in astronomy, establishment of a network of significant private observatories across the nation, and formation of Australia’s earliest astronomical groups and societies.

During this period, amateur astronomers were able to make a significant contribution internationally to positional astronomy. This paper briefly examines amateur-professional relations in Australian astronomy at the time, and the interplay of power and politics.
Astronomical Observations in Asia from Delisle’S Manuscript Preserved in the paris Observatory Library
Authors: Débarbat S.
Published: March 2016

Delisle, born in 1688 April 4, is well known as a collector of astronomical data from all over the world. Part of his manuscripts are preserved in the Paris Observatory Library. He is said to have collected all available astronomical data at the time he was in activity in France and in Russia where he spent more than twenty years. He had more correspondents and among them, in Asia, Father Gaubil, of which more than one hundred letters are in the Paris Observatory Archives, providing priceless informations to astronomical researchers, historians and others.
X-Ray Burst Sources
Authors: Lewin Walter H.G.
Published: March 2016

Since those reviews there have been very important new developments. First, a surprisingly new animal, GRO J1744—28 (better known as the Bursting Pulsar), made its debut in 1995. Second, but NOT last, in 1996/97 kHz pulsations were discovered in the persistent emission of several burst sources, and near coherent pulsations were detected in type I X-ray bursts.
Nature of Turbulence: Governing Factor of Accretion Disk Dynamics
Authors: Lominadze J. G.
Published: March 2016

It has long been suggested that turbulence provide viscous torques to transport angular momentum outward and flow mass inward in accretion disks (von Weizsäcker 1948, Shakura & Sunyaev 1973). Recent advances in subject of understanding of accretion disk turbulence are mach linked with magnetised disks (cf. Vishniac & Diamond 1992, Balbus, Gammie & Hawley 1994, Brandenburg et al. 1995, Stone et al 1996). However, not all the disks are magnetically coupled (see Balbus, Hawley & Stone 1996). Two different sources that are able to sustain turbulence in not magnetised accretion disk are the following:
X-Ray Variability in Active Galactic Nuclei: Two Things That Everybody Should Know
Authors: Leighly Karen M.
Published: March 2016

X-ray variability is a distinguishing property of Active Galactic Nuclei (AGN), and the energetics and time scales of the emission dictate that the X-rays must originate very close to the central engine. In this review I discuss two basic topics from AGN variability research. The first is the correlation of the variability time scale with the X-ray luminosity, and the second is the structure of the X-ray light curve. In each case, I first review the old results that have been known for approximately the last 10 years and then I discuss very new results which may force us to modify our ideas about the origin of AGN X-ray variability. Note that I am discussing the variability of non-blazar type AGN.
Active Galactic Nuclei: Variability at Many Wavelengths
Authors: Courvoisier Thierry J.-L.
Published: March 2016

Active Galactic Nuclei (AGN) are thought to be powered by accretion onto a massive black hole. Understanding how gravitational energy freed by the infall of matter into the black hole is transferred to the radiating regions of the nucleus is one of the main challenges of AGN research. The question is made very complex by the presence of several cooling mechanisms with very diverse physical properties: We observe synchrotron radiation, thermal emission from hot dust, possibly thermal optical and ultraviolet emission and Comptonization processes in the X-ray domain. For each component the radiation is a signature of the cooling process rather than of the heating process. It is our hope that by observing the links and correlations between the emission of the different components we will be able to understand how they are interrelated and how they get their energy supply from the accretion process.
Composition of the Solar Wind, Secondary Ion Generation and Pick-Up
Authors: Mall Urs
Published: March 2016

The solar wind is an ionized gas which, as a consequence of a hot solar corona and a low fluid pressure in the interstellar space, continuously emanates from the Sun into space to define a region known as the heliosphere. Since the electrical conductivity of the solar wind is very high, diffusion of the magnetic field through the plasma is not taken into account. In this picture (the frozen-in approximation) one imagines that the solar magnetic field is dragged into the heliospheric space by the radially outflowing solar wind. The structure of the solar wind is therefore intimately related to the structure of the solar corona and the solar magnetic field. The solar wind plasma itself is composed of protons, electrons, alpha particles, and a minor fraction of heavy ions.
Astronomy Teaching and Research in Nigeria
Authors: Onuora Lesley
Published: March 2016

Astronomy research and teaching has been actively carried out in the Department of Physics and Astronomy at the University of Nigeria, Nsukka for the past 20 years and before that, in the Department of Mathematics. Economic problems, lack of recent journals, text books and computing facilities, and very poor communications have made it increasingly difficult for these programmes to continue. Added to these problems there is often unrest in the Universities resulting in frequent closures and almost constant uncertainty about payment of the already poor salaries. It is a wonder that anyone could be even thinking of astronomy.
A Global Network of Small Telescopes as a Resource for Astronomical Research and Education
Authors: Crawford David L.
Published: March 2016

There is no question that relatively small telescopes are powerful tools for astronomy, just as they always have been. With the new detectors and full usage of computers, they have become even more powerful, enabling us to do with a one-meter aperture telescope today more than 4-meter or 5-meter telescopes could do only a few decades ago. And the small ones cost a lot less to build and operate than the large ones. As such, small telescopes are the main hope for observing time for the many astronomers worldwide who need them as part of their research (or educational) tools. They can make a major impact on many areas of research and will be of great value for scientific education as well. Astronomy is very interesting to students and to the general public, not just to astronomers. Furthermore, most areas of astronomical research are data poor and more telescopes are needed to effectively attack the problems. Only a very few of us have adequate telescope time for our research or educational needs.
Statistical Connections among Water Vapor Megamasers
Authors: Wilson A. S. , Braatz J. A. , Henkel C.
Published: March 2016

We review correlations between water megamaser emission and other properties of AGN. Galaxies detected as water megamaser emitters tend to be nearer, brighter at mid-infrared and possibly centimeter wavelengths, and more highly inclined than undetected galaxies. Only Seyfert 2s and LINERs (no Seyfert Is) are detected. It is argued that the primary parameter determining whether an active galaxy is detectable as an H2O megamaser is the gas column along our line of sight to the nucleus.
SETI from the Moon: Avoiding Radio Pollution for Future Radio-Astronomy
Authors: Heidmann J.
Published: March 2016

Because of the ever increasing human-made radio frequency interference (RFI), we propose to IAU a Resolution for protecting the well singled out lunar farside 100 km diameter SAHA crater from any future RFI for the scientific benefit of the coming decades high-sensitivity radioastronomy at large. Immediate and pragmatic action is strongly recommended. Our strategy, different from the ones of a recent ITU Recommendation, could increase our bargaining possibilities.
Video Techniques for Observation of the Leonid Storms
Authors: Hawkes R.L.
Published: March 2016

Video techniques, which provide high sensitivity, portability, moderate spatial resolution and excellent temporal resolution promise to be one of the most valuable methods for study of the forthcoming Leonid storm(s). While an unintensified video camera will detect very bright meteors (typically about 0 magnitude), some sort of image intensifier is needed to attain high meteor rates. Most current systems use a second or third generation microchannel plate (MCP) image intensifier lens or fibre-optically coupled to a charge coupled device (CCD) video detector.
RADAR Observations of Leonids in Japan
Authors: Watanabe Jun-Ichi
Published: March 2016

We are observing meteor showers using the MU radar located at Shigaraki, Japan. This is a Mesosphere, Stratosphere and Troposphere radar, belonging to the Kyoto University, with a frequency and a peak power of 46.5M.ffz and 1MW, respectively. This system is characterized by the versatility of the antenna array. By using four antennas out of 475 Yagi arrays together with four receiver channels, we can observe more than several hundred meteor echoes per hour. The beam applied at the meteor observation is a static “doughnut beam”, which is the rotational symmetrical pattern to the vertical line. This beam is effective enough to detect meteor echoes of which the zenith angle is smaller than about 50°, which characterizes the MU radar as an all sky monitoring radar of meteor echoes. For the low velocity meteors, most of the echoes satisfy a condition of the perpendicular reflection, and we can derive the position of the radiant point statistically, and succeeded its application for the Geminids (Watanabe et al. 1992a). For the high velocity meteors, most of the echoes are in the overdense condition. However, we can discriminate the echoes of a specific meteor shower out of the data by checking the echo duration, the height, the strength or the combination of them. We have been monitoring the Perseids from 1990, and succeeded to reveal the unusual activity in 1991 (Watanabe et al. 1992b). For the Leonids, we are continuing the observation from 1991. The drastic increase of the activity has been detected around 23h UT on November 17, 1994. The number of the observed long duration echoes, which came from possibly bright Leonids meteors, were 80 per hour. This should be the beginning of the Leonids activity toward the 1998-1999. We are planning to continue this observation until the end of the activity in the 2000’s.
Joint Discussion 24: Pulsating Stars – Recent Developments in Theory and Observation
Authors: Sasselov D. , Takeuti M.
Published: March 2016

The past few years have seen the emergence of new observational approaches to the study of pulsating stars. Massive photometric surveys are discovering new variables by the tens of thousands. For example, the number of Cepheids and RR Lyrae has increased manifold over the past two years – many of these new distant pulsating stars have now better light curves than their well-known nearby counterparts. The new observational breakthrough has opened many theoretical issues. Some of these can be tackled with the set of new opacities (from Lawrence Livermore and from the Opacity Project), others seem to require new theoretical insights.
Dynamics of Jupiter’s Atmosphere
Authors: Ingersoll A.P. , Vasavada A.R.
Published: March 2016

Results from the Galileo probe and orbiter are compared with Voyager and ground-based results. The probe made measurements to the 20-bar level, well below the nominal cloud base at 5 bars and well below the level where sunlight is absorbed. The winds increased with depth within the clouds and then remained constant below cloud base. This rules out most “thin weather layer” models of Jovian meteorology. Water, H2S, and NH3 were depleted relative to “solar” abundances at the nominal cloud base but increased with depth below 10 bars. Apparently the probe entered a dry downdraft that penetrated to 20 bars. Consistent with this result, the orbiter found water varying by factors of 100 from place to place, with the lowest values at the sites that resemble the one where the probe went in. The orbiter also revealed that these sites are regions of horizontal convergence of the cloud top winds, which is consistent with the downdraft hypothesis.
Satellite Atmospheres and Magnetospheres
Authors: Kliore A.J.
Published: March 2016

Galileo radio-occultation measurements show that all four of the Galilean satellites possess ionospheres. Peak ionospheric densities for the icy satellites are several thousand electrons per cubic centimeter, and the distributions are not spherically symmetric. Io’s ionosphere is much denser and remarkably similar to that measured by Voyager.
Highlights From ISO: The Isocam Camera
Authors: Cesarsky Catherine J.
Published: March 2016

Over one year and a half after its first light in orbit, the ISOCAM camera on board the Infrared Space Observatory is bringing back very exciting results. Its spectacular infrared viewing of the Universe sheds new light on the nature of the interstellar dust, on the birth of young stars embedded in dark clouds as well as on bursts of star formation in external galaxies.
First Results and Discoveries with the ISO Short-Wavelength Spectrometer
Authors: Graauw Thijs De
Published: March 2016

The Short-Wavelength Spectrometer(SWS) is one of the four instruments on-board of ESA’s Infrared Space Observatory(ISO), launched on 15 Nov. 1995. It covers the wave-length range of 2.38-45.2μm with a spectral resolution ranging from 1000-2000. An overview is given of the in-orbit performance and a summary of the main scientific results and discoveries obtained in the first 18 months of operation of the ISO-SWS.
Highlights of the ISO Long-Wavelength Spectrometer
Authors: Clegg Peter E.
Published: March 2016

It is a pleasure for me to present, on behalf of the international consortium of scientist and engineers who built the instrument, some interim results from the Long-Wavelength Spectrometer (LWS). I shall briefly review the scientific capabilities of the instrument before describing some of the highlights of its scientific programme.
Deep Surveys and Cosmology
Authors: Oliver S. J. , Sergeant S. , Goldschmidt P. , Mann R.G. , Rowan-Robinson M. , Eaton N. , Efsathiou A. , Gruppioni C. , Sumner T.J. , Mobasher B. , Verma A. , Danese L. , Egami E. , Elbaz D. , Franceschini A. , Gonzalez-Serrano I. , Kontizas M. , Lawrence A. , Mcmahon R. , Nørgaard-Nielsen H.U. , Pérez-Fournon I.
Published: March 2016

Surveys with ISO (Kessler et al 1996), in particular with the CAM (Cesarsky et al 1996) and PHOT (Lemke et al 1996) instruments, will greatly extend our understanding of extra-galactic populations and their cosmological evolution. The main advantages that ISO surveys have over e.g IRAS are increased sensitivity/depth and wavelength coverage. Within the Guaranteed and Open Time programmes there are many field surveys which will efficiently map the limits in these parameters. In this talk I will briefly overview those surveys before concentrating in more detail on one survey in particular, the ISO survey of the Hubble Deep Field (HDF), to illustrate the kind of results that can be expected.
Very Deep Surveys
Authors: Taniguchi Y.
Published: March 2016

When and how did galaxies form? In order to understand this important problem in astrophysics, many observational studies have been conducted so far. Deep survey observations in the optical are powerful for detecting very faint sources in the high-z universe The observed surface density of such high-z star forming galaxies may, however, be smaller than the value expected from the local density of luminous galaxies (e.g., Lanzetta et al. 1996; Steidel et al. 1996) and it is possible that we are missing classes of objects with substantial reddening and have not yet sampled fully the high-z counterparts of typical nearby galaxies. Since the nearby, well evolved galaxies consist of old low-mass stars, it is important to find galaxies with numerous low-mass stars. These stars emit their energy from the optical to near infrared (NIR) mostly, implying that they are more luminous in the NIR and MIR (mid-infrared) than in the optical if they were present at high redshifts.
Algae Blooms and Gas Wells Drive Lake Erie Methane Emissions
Authors: Heisman Rebecca
Published: March 2016

In one of the first studies to investigate large lakes as methane sources, researchers found that Lake Erie is releasing more of the potent greenhouse gas than expected.
Silicon oxycarbide glass-graphene composite paper electrode for long-cycle lithium-ion batteries
Authors: David Lamuel , Bhandavat Romil , Barrera Uriel , Singh Gurpreet
Published: March 2016

Silicon and graphene are promising anode materials for lithium-ion batteries because of their high theoretical capacity; however, low volumetric energy density, poor efficiency and instability in high loading electrodes limit their practical application. Here we report a large area (approximately 15 cm × 2.5 cm) self-standing anode material consisting of molecular precursor-derived silicon oxycarbide glass particles embedded in a chemically-modified reduced graphene oxide matrix. The porous reduced graphene oxide matrix serves as an effective electron conductor and current collector with a stable mechanical structure, and the amorphous silicon oxycarbide particles cycle lithium-ions with high Coulombic efficiency. The paper electrode (mass loading of 2 mg cm−2) delivers a charge capacity of ∼588 mAh g−1electrode(∼393 mAh cm−3electrode) at 1,020th cycle and shows no evidence of mechanical failure. Elimination of inactive ingredients such as metal current collector and polymeric binder reduces the total electrode weight and may provide the means to produce efficient lightweight batteries.
Genome scale patterns of supercoiling in a bacterial chromosome
Authors: Lal Avantika , Dhar Amlanjyoti , Trostel Andrei , Kouzine Fedor , Seshasayee Aswin S. N. , Adhya Sankar
Published: March 2016

DNA in bacterial cells primarily exists in a negatively supercoiled state. The extent of supercoiling differs between regions of the chromosome, changes in response to external conditions and regulates gene expression. Here we report the use of trimethylpsoralen intercalation to map the extent of supercoiling across the Escherichia coli chromosome during exponential and stationary growth phases. We find that stationary phase E. coli cells display a gradient of negative supercoiling, with the terminus being more negatively supercoiled than the origin of replication, and that such a gradient is absent in exponentially growing cells. This stationary phase pattern is correlated with the binding of the nucleoid-associated protein HU, and we show that it is lost in an HU deletion strain. We suggest that HU establishes higher supercoiling near the terminus of the chromosome during stationary phase, whereas during exponential growth DNA gyrase and/or transcription equalizes supercoiling across the chromosome.
Loss of MAX results in meiotic entry in mouse embryonic and germline stem cells
Authors: Suzuki Ayumu , Hirasaki Masataka , Hishida Tomoaki , Wu Jun , Okamura Daiji , Ueda Atsushi , Nishimoto Masazumi , Nakachi Yutaka , Mizuno Yosuke , Okazaki Yasushi , Matsui Yasuhisa , Belmonte Juan Carlos Izpisua , Okuda Akihiko
Published: March 2016

Meiosis is a unique process that allows the generation of reproductive cells. It remains largely unknown how meiosis is initiated in germ cells and why non-germline cells do not undergo meiosis. We previously demonstrated that knockdown of Max expression, a gene encoding a partner of MYC family proteins, strongly activates expression of germ cell-related genes in ESCs. Here we find that complete ablation of Max expression in ESCs results in profound cytological changes reminiscent of cells undergoing meiotic cell division. Furthermore, our analyses uncovers that Max expression is transiently attenuated in germ cells undergoing meiosis in vivo and its forced reduction induces meiosis-like cytological changes in cultured germline stem cells. Mechanistically, Max depletion alterations are, in part, due to impairment of the function of an atypical PRC1 complex (PRC1.6), in which MAX is one of the components. Our data highlight MAX as a new regulator of meiotic onset.
Essential role of the TFIID subunit TAF4 in murine embryogenesis and embryonic stem cell differentiation
Authors: Langer Diana , Martianov Igor , Alpern Daniel , Rhinn Muriel , Keime Céline , Dollé Pascal , Mengus Gabrielle , Davidson Irwin
Published: March 2016

TAF4 (TATA-binding protein-associated factor 4) and its paralogue TAF4b are components of the TFIID core module. We inactivated the murine Taf4a gene to address Taf4 function during embryogenesis. Here we show that Taf4a−/− embryos survive until E9.5 where primary germ layers and many embryonic structures are identified showing Taf4 is dispensable for their specification. In contrast, Taf4 is required for correct patterning of the trunk and anterior structures, ventral morphogenesis and proper heart positioning. Overlapping expression of Taf4a and Taf4b during embryogenesis suggests their redundancy at early stages. In agreement with this, Taf4a−/− embryonic stem cells (ESCs) are viable and comprise Taf4b-containing TFIID. Nevertheless, Taf4a−/− ESCs do not complete differentiation into glutamatergic neurons and cardiomyocytes in vitro due to impaired preinitiation complex formation at the promoters of critical differentiation genes. We define an essential role of a core TFIID TAF in differentiation events during mammalian embryogenesis.
Three-dimensional structural dynamics and fluctuations of DNA-nanogold conjugates by individual-particle electron tomography
Authors: Zhang Lei , Lei Dongsheng , Smith Jessica M. , Zhang Meng , Tong Huimin , Zhang Xing , Lu Zhuoyang , Liu Jiankang , Alivisatos A. Paul , Ren Gang
Published: March 2016

DNA base pairing has been used for many years to direct the arrangement of inorganic nanocrystals into small groupings and arrays with tailored optical and electrical properties. The control of DNA-mediated assembly depends crucially on a better understanding of three-dimensional structure of DNA-nanocrystal-hybridized building blocks. Existing techniques do not allow for structural determination of these flexible and heterogeneous samples. Here we report cryo-electron microscopy and negative-staining electron tomography approaches to image, and three-dimensionally reconstruct a single DNA-nanogold conjugate, an 84-bp double-stranded DNA with two 5-nm nanogold particles for potential substrates in plasmon-coupling experiments. By individual-particle electron tomography reconstruction, we obtain 14 density maps at ∼2-nm resolution. Using these maps as constraints, we derive 14 conformations of dsDNA by molecular dynamics simulations. The conformational variation is consistent with that from liquid solution, suggesting that individual-particle electron tomography could be an expected approach to study DNA-assembling and flexible protein structure and dynamics.
A Molecular Chipper technology for CRISPR sgRNA library generation and functional mapping of noncoding regions
Authors: Cheng Jijun , Roden Christine A. , Pan Wen , Zhu Shu , Baccei Anna , Pan Xinghua , Jiang Tingting , Kluger Yuval , Weissman Sherman M. , Guo Shangqin , Flavell Richard A. , Ding Ye , Lu Jun
Published: March 2016

Clustered regularly-interspaced palindromic repeats (CRISPR)-based genetic screens using single-guide-RNA (sgRNA) libraries have proven powerful to identify genetic regulators. Applying CRISPR screens to interrogate functional elements in noncoding regions requires generating sgRNA libraries that are densely covering, and ideally inexpensive, easy to implement and flexible for customization. Here we present a Molecular Chipper technology for generating dense sgRNA libraries for genomic regions of interest, and a proof-of-principle screen that identifies novel cis-regulatory domains for miR-142 biogenesis. The Molecular Chipper approach utilizes a combination of random fragmentation and a type III restriction enzyme to derive a densely covering sgRNA library from input DNA. Applying this approach to 17 microRNAs and their flanking regions and with a reporter for miR-142 activity, we identify both the pre-miR-142 region and two previously unrecognized cis-domains important for miR-142 biogenesis, with the latter regulating miR-142 processing. This strategy will be useful for identifying functional noncoding elements in mammalian genomes.
Balanced motor primitive can explain generalization of motor learning effects between unimanual and bimanual movements
Authors: Takiyama Ken , Sakai Yutaka
Published: March 2016

Motor learning in unimanual and bimanual planar reaching movements has been intensively investigated. Although distinct theoretical frameworks have been proposed for each of these reaching movements, the relationship between these movements remains unclear. In particular, the generalization of motor learning effects (transfer of learning effects) between unimanual and bimanual movements has yet to be successfully explained. Here, by extending a motor primitive framework, we analytically proved that the motor primitive framework can reproduce the generalization of learning effects between unimanual and bimanual movements if the mean activity of each primitive for unimanual movements is balanced to the mean for bimanual movements. In this balanced condition, the activity of each primitive is consistent with previously reported neuronal activity. The unimanual-bimanual balance leads to the testable prediction that generalization between unimanual and bimanual movements is more widespread to different reaching directions than generalization within respective movements. Furthermore, the balanced motor primitive can reproduce another previously reported phenomenon: the learning of different force fields for unimanual and bimanual movements.
Changes in Gab2 phosphorylation and interaction partners in response to interleukin (IL)-2 stimulation in T-lymphocytes
Authors: Osinalde Nerea , Sánchez-Quiles Virginia , Blagoev Blagoy , Kratchmarova Irina
Published: March 2016

Interleukin-2 (IL-2) stimulation results in T-cell growth as a consequence of activation of highly sophisticated and fine-tuned signaling pathways. Despite lacking intrinsic enzymatic activity, scaffold proteins such as Gab2, play a pivotal role in IL-2-triggered signal transduction integrating, diversifying and amplifying the signal by serving as a platform for the assembly of effectors proteins. Traditionally, Gab2-mediated protein recruitment was believed to solely depend on cytokine-induced phosphotyrosine moieties. At present, phosphorylation on serine/threonine residues is also emerging as a key mediator of Gab2-dependent signal regulation. Despite its relevance, IL-2-triggered regulation on Gab2 phosphorylation is yet poorly understood. Combining antibody- and TiO2-based enrichment of the scaffold protein with SILAC quantitative mass spectrometry we disclose the prominent regulation IL-2 exerts on Gab2 serine/threonine phosphorylation by showing that at least 18 serines and 1 threonine, including previously non-reported ones, become phosphorylated in response to cytokine stimulation. Additionally, we decipher the interactome of the docking protein in resting and cytokine-treated T-lymphocytes and besides well-known Gab2 interactors we discover three novel cytokine-inducible Gab2-binding proteins. Thus, our data provide novel insights and a wealth of candidates for future studies that will shed light into the role of Gab2 in IL-2-initiated signal transduction.
Multiplexed Affinity-Based Separation of Proteins and Cells Using Inertial Microfluidics
Authors: Sarkar Aniruddh , Hou Han Wei , Mahan Alison. E. , Han Jongyoon , Alter Galit
Published: March 2016

Isolation of low abundance proteins or rare cells from complex mixtures, such as blood, is required for many diagnostic, therapeutic and research applications. Current affinity-based protein or cell separation methods use binary ‘bind-elute’ separations and are inefficient when applied to the isolation of multiple low-abundance proteins or cell types. We present a method for rapid and multiplexed, yet inexpensive, affinity-based isolation of both proteins and cells, using a size-coded mixture of multiple affinity-capture microbeads and an inertial microfluidic particle sorter device. In a single binding step, different targets–cells or proteins–bind to beads of different sizes, which are then sorted by flowing them through a spiral microfluidic channel. This technique performs continuous-flow, high throughput affinity-separation of milligram-scale protein samples or millions of cells in minutes after binding. We demonstrate the simultaneous isolation of multiple antibodies from serum and multiple cell types from peripheral blood mononuclear cells or whole blood. We use the technique to isolate low abundance antibodies specific to different HIV antigens and rare HIV-specific cells from blood obtained from HIV+ patients.
Human cytomegalovirus gH stability and trafficking are regulated by ER-associated degradation and transmembrane architecture
Authors: Gardner Thomas J. , Hernandez Rosmel E. , Noriega Vanessa M. , Tortorella Domenico
Published: March 2016

The prototypic betaherpesvirus human cytomegalovirus (CMV) establishes life-long persistence within its human host. While benign in healthy individuals, CMV poses a significant threat to the immune compromised, including transplant recipients and neonates. The CMV glycoprotein complex gH/gL/gO mediates infection of fibroblasts and together with the gH/gL/UL128/130/131 a pentameric complex permits infection of epithelial, endothethial and myeloid cells. Given the central role of the gH/gL complex during infection, we were interested in studying cellular trafficking of the gH/gL complex through generation of human cells that stably express gH and gL. When expressed alone, CMV gH and gL were degraded through the ER-associated degradation (ERAD) pathway. However, co-expression of these proteins stabilized the polypeptides and enhanced their cell-surface expression. To further define regulatory factors involved in gH/gL trafficking, a CMV gH chimera in which the gH transmembrane and cytoplasmic tail were replaced with that of human CD4 protein permitted cell surface gH expression in absence of gL. We thus demonstrate the ability of distinct cellular processes to regulate the trafficking of viral glycoproteins. Collectively, the data provide insight into the processing and trafficking requirements of CMV envelope protein complexes and provide an example of the co-opting of cellular processes by CMV.
Genetic variant in IL-33 is associated with idiopathic recurrent miscarriage in Chinese Han population
Authors: Yue Jun , Tong Yu , Xie Lan , Ma Tao , Yang Jiyun
Published: March 2016

Recurrent miscarriage (RM) is the occurrence of repeated pregnancies that end in miscarriage of the fetus before 20 weeks of gestation. At least 50% of the RM patients are considered idiopathic. High IL-33 levels are critical in early pregnancy and impact the outcome of subsequent pregnancies. However, the association of polymorphisms of IL-33 with idiopathic RM is still unclear. The present study was initiated to investigate whether IL-33 polymorphisms are risk factors for idiopathic RM in Chinese Han population. Study subjects comprised of 321 cases and 384 controls. Five polymorphisms (rs10435816, rs16924159, rs16924171, rs1929992, rs1332290) in IL-33 and serum IL-33 concentrations were assessed. rs16924159 variant exhibits significant association with RM in additive and recessive genetic model (additive model P = 0.015, recessive model P = 0.007). In contrast, rs10435816, rs16924171, rs1929992 and rs1332290 are not significantly associated with RM. Serum IL-33 levels are significantly lower in RM cases than in control (173.51 ± 94.12 versus. 200.97 ± 110.06 (pg/ml), P = 4.57 × 10−4). There are lower levels of serum IL-33 in rs16924159 homozygous mutant (AA) than homozygous wild-type (GG) in this study population, including cases and control groups (172.18 ± 103.01 versus. 205.82 ± 119.01 (pg/ml), P = 0.006). Reduced IL-33 levels and rs16924159 IL-33 variant may contribute to the pathogenesis of idiopathic RM in Chinese Han population.
X-ray Absorption Spectroscopy Study of the Effect of Rh doping in Sr2IrO4
Authors: Sohn C. H. , Cho Deok-Yong , Kuo C.-T. , Sandilands L. J. , Qi T. F. , Cao G. , Noh T. W.
Published: March 2016

We investigate the effect of Rh doping in Sr2IrO4 using X-ray absorption spectroscopy (XAS). We observed appearance of new electron-addition states with increasing Rh concentration (x in Sr2Ir1−xRhxO4) in accordance with the concept of hole doping. The intensity of the hole-induced state is however weak, suggesting weakness of charge transfer (CT) effect and Mott insulating ground states. Also, Ir Jeff = 1/2 upper Hubbard band shifts to lower energy as x increases up to x = 0.23. Combined with optical spectroscopy, these results suggest a hybridisation-related mechanism, in which Rh doping can weaken the (Ir Jeff = 1/2)–(O 2p) orbital hybridisation in the in-planar Rh-O-Ir bond networks.
Photo-degradation in air of the active layer components in a thiophene–quinoxaline copolymer:fullerene solar cell
Authors: Hansson Rickard , Lindqvist Camilla , Ericsson Leif K. E. , Opitz Andreas , Wang Ergang , Moons Ellen
Published: March 2016

We have studied the photo-degradation in air of a blend of [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) and poly[2,3-bis-(3-octyloxyphenyl)quinoxaline-5,8-diyl-alt-thiophene-2,5-diyl] (TQ1), and how the photo-degradation affects the solar cell performance.
Catalyst hydrothermal deactivation and metal contamination during the in situ catalytic pyrolysis of biomass
Authors: Stefanidis Stylianos D. , Kalogiannis Konstantinos G. , Pilavachi Petros A. , Fougret Christoph M. , Jordan Edgar , Lappas Angelos A.
Published: March 2016

We investigated the effects of hydrothermal deactivation and biomass metal contamination on the properties and catalytic performance of commercial ZSM-5 catalysts.
Comparison of heterogenized molecular and heterogeneous oxide catalysts for photoelectrochemical water oxidation
Authors: Li Wei , He Da , Sheehan Stafford W. , He Yumin , Thorne James E. , Yao Xiahui , Brudvig Gary W. , Wang Dunwei
Published: March 2016

Molecular and heterogeneous water oxidation catalysts improve the performance of hematite as a photoanode via fundamentally different mechanisms.
Non-invasive evaluation of cardiac repolarization in mice exposed to single-wall carbon nanotubes and ceria nanoparticles via intratracheal instillation
Authors: Kosaraju Karshak , Lancaster Jarrett L. , Meier Stephen R. , Crawford Steven , Hurley Steven , Aravamudhan Shyam , Starobin Joseph M.
Published: March 2016

A novel method is proposed for non-invasive determination of cardiovascular toxicity due to ceria nanoparticles and single-wall carbon nanotubes from intratracheal instillation in mice.
Molecular dynamic simulations of the core–shell microsphere of nanosilica grafted by acrylamide acrylic acid copolymer PAMAA: study of its microstructure and interaction between microsphere and additives
Authors: Dai Shanshan , Zhang Jinghan , Zhang Tailiang , Huang Zhiyu , Quan Hongping , Lu Hongsheng , Zhao Xiaowen
Published: March 2016

Different additives have a remarkable effect on the microstructure of microsphere in aqueous solution.