bluuebunny/crossref_metadata_2025 huggingface dataset:
Functional role of histone variant Htz1 in the stress response to oleate in Saccharomyces cerevisiae
Authors: Liu Hongde , Li Guanghui , Liu Lingjie , Wan Yakun
Published: May 2015

Chromatin structure is implicated in regulating gene transcription in stress response. Transcription factors, transferases and deacetylases, such as multicopy suppressor of SNF1 protein 2 (Msn2), SET domain-containing protein 1 (Set1) and sucrose NonFermenting protein 1 (Snf1), have been identified as key regulators in stress response. In the present study, we reported the dynamics of nucleosome occupancy, Histone Two A Z1 (Htz1) deposition and histone H3 lysine 4 dimethylation (H3K4me2) and histone H3 lysine 79 trimethylation (H3K79me3) in Saccharomyces cerevisiae under oleate stress. Our results indicated that citrate cycle-associated genes are enhanced and ribosome genes are repressed during the glucose-oleate shift. Importantly, Htz1 acts as a sensor for oleate stress. High-throughput ChIP-chip analysis showed that Htz1 has redistributed across the genome during oleate stress. The number of Htz1-bound genes increases with stress and the number of Htz1-bound ribosome genes decreases with stress. The dynamics of Htz1 and H3K79me3 around transcription factor-binding sites correlate with transcriptional changes. Moreover, we found that nucleosome dynamics are coupled with Htz1 binding changes upon stress. In unstressed conditions (2% glucose), nucleosome occupancy is comparable between Htz1-bound genes and Htz1-depleted genes; in stressed conditions (0.2% oleate for 8 h), the nucleosome occupancy of Htz1-depleted genes is significantly lower than that of Htz1-bound genes. We also found that Msn2 acts an important role in response to the oleate stress and Htz1 is dynamic in Msn2-target genes. Htz1 senses the oleate stress and undergoes a global redistribution and this change couples dynamics of nucleosome occupancy. Our analysis suggests that Htz1 and nucleosome dynamics change in response to oleate stress.
Quantifying urban economic resilience through labour force interdependence
Authors: Shutters Shade T , Muneepeerakul Rachata , Lobo José
Published: May 2015

Resilience is increasing rapidly as a framework to understand and manage coupled human–natural systems. Yet the concept of resilience is rarely quantified. Here we quantify system resilience by operationalizing the notion of system tightness. Multiple resilience frameworks recognize the strong relationship between system tightness and resilience, though they differ on the directionality of that relationship. Thus, by measuring the system tightness we ultimately measure urban economic resilience, with the added benefit of empirically determining the directionality of the relationship between tightness and resilience. We then assess how well this measure predicts the response of urban economies to the recent so-called Great Recession. Results show that cities with lower tightness (higher resilience) fared better during the recession with respect to several economic productivity measures. However, in the absence of shocks, those with higher tightness (lower resilience) exhibit superior economic performance. Thus, a tradeoff between efficiency and resilience is nicely reflected in the empirical data. Although this study deals with economic shocks, quantitative metrics based on its methodology may help anticipate a city’s response to shocks more generally, such as natural disasters, climate change, social unrest or significant policy shifts.
Sub-nanometer periodic nonlinearity error in absolute distance interferometers
Authors: Yang Hongxing , Huang Kaiqi , Hu Pengcheng , Zhu Pengfei , Tan Jiubin , Fan Zhigang
Published: May 2015

Periodic nonlinearity which can result in error in nanometer scale has become a main problem limiting the absolute distance measurement accuracy. In order to eliminate this error, a new integrated interferometer with non-polarizing beam splitter is developed. This leads to disappearing of the frequency and/or polarization mixing. Furthermore, a strict requirement on the laser source polarization is highly reduced. By combining retro-reflector and angel prism, reference and measuring beams can be spatially separated, and therefore, their optical paths are not overlapped. So, the main cause of the periodic nonlinearity error, i.e., the frequency and/or polarization mixing and leakage of beam, is eliminated. Experimental results indicate that the periodic phase error is kept within 0.0018°.
Local electronic states of Fe4N films revealed by x-ray absorption spectroscopy and x-ray magnetic circular dichroism
Authors: Ito Keita , Toko Kaoru , Takeda Yukiharu , Saitoh Yuji , Oguchi Tamio , Suemasu Takashi , Kimura Akio
Published: May 2015

We performed x-ray absorption spectroscopy (XAS) and x-ray magnetic circular dichroism (XMCD) measurements at Fe L2,3 and N K-edges for Fe4N epitaxial films grown by molecular beam epitaxy. In order to clarify the element specific local electronic structure of Fe4N, we compared experimentally obtained XAS and XMCD spectra with those simulated by a combination of a first-principles calculation and Fermi's golden rule. We revealed that the shoulders observed at Fe L2,3-edges in the XAS and XMCD spectra were due to the electric dipole transition from the Fe 2p core-level to the hybridization state generated by σ* anti-bonding between the orbitals of N 2p at the body-centered site and Fe 3d on the face-centered (II) sites. Thus, the observed shoulders were attributed to the local electronic structure of Fe atoms at II sites. As to the N K-edge, the line shape of the obtained spectra was explained by the dipole transition from the N 1s core-level to the hybridization state formed by π* and σ* anti-bondings between the Fe 3d and N 2p orbitals. This hybridization plays an important role in featuring the electronic structures and physical properties of Fe4N.
Synthesis of graphene-like transparent conductive films on dielectric substrates using a modified filtered vacuum arc system
Authors: Lux Helge , Siemroth Peter , Sgarlata Anna , Prosposito Paolo , Schubert Markus Andreas , Casalboni Mauro , Schrader Sigurd
Published: May 2015

Here, we present a reliable process to deposit transparent conductive films on silicon oxide, quartz, and sapphire using a solid carbon source. This layer consists of partially ordered graphene flakes with a lateral dimension of about 5 nm. The process does not require any catalytic metal and exploits a high current arc evaporation (Φ-HCA) to homogeneously deposit a layer of carbon on heated substrates. A gas atmosphere consisting of Argon or Argon/Hydrogen blend acting as a buffer influences the morphology of the growing film. scanning tunneling microscopy, transmission electron microscopy, and Raman spectra were used for a thorough characterization of the samples in order to optimize the growth parameters. The best carbon layers have a surface resistance of 5.7 × 103 Ω◻ whereas the optical transparency of the coatings is 88% with an excellent homogeneity over areas of several cm2. Such results are compatible with most semiconductor fabrication processes and make this method very promising for various industrial applications.
Research Update: Orbital polarization in LaNiO3-based heterostructures
Authors: Disa Ankit S. , Walker F. J. , Ismail-Beigi Sohrab , Ahn Charles H.
Published: May 2015

The relative energies and occupancies of valence orbital states can dramatically influence collective electronic and magnetic phenomena in correlated transition metal oxide systems. We review the current state of research on the modification and control of these orbital properties in rare-earth nickelates, especially LaNiO3, a model degenerate d orbital system where significant recent progress has been made. Theoretical and experimental results on thin films and heterostructures are described, including the influence of electronic correlation effects. We highlight the latest approaches to achieving non-degenerate bands and discuss the outlook and applicability of this body of knowledge to other correlated metal oxide systems.
Persistent semi-metal-like nature of epitaxial perovskite CaIrO3 thin films
Authors: Biswas Abhijit , Jeong Yoon Hee
Published: May 2015

Strong spin-orbit coupled 5d transition metal based ABO3 oxides, especially iridates, allow tuning parameters in the phase diagram and may demonstrate important functionalities, for example, by means of strain effects and symmetry-breaking, because of the interplay between the Coulomb interactions and strong spin-orbit coupling. Here, we have epitaxially stabilized high quality thin films of perovskite (Pv) CaIrO3. Film on the best lattice-matched substrate shows semi-metal-like characteristics. Intriguingly, imposing tensile or compressive strain on the film by altering the underlying lattice-mismatched substrates still maintains semi-metallicity with minute modification of the effective correlation as tensile (compressive) strain results in tiny increases (decreases) of the electronic bandwidth. In addition, magnetoresistance remains positive with a quadratic field dependence. This persistent semi-metal-like nature of Pv-CaIrO3 thin films with minute changes in the effective correlation by strain may provide new wisdom into strong spin-orbit coupled 5d based oxide physics.
Optical control of charged exciton states in tungsten disulfide
Authors: Currie M. , Hanbicki A. T. , Kioseoglou G. , Jonker B. T.
Published: May 2015

A method is presented for optically preparing WS2 monolayers to luminescence from only the charged exciton (trion) state–completely suppressing the neutral exciton. When isolating the trion state, we observed changes in the Raman A1g intensity and an enhanced feature on the low energy side of the E12g peak. Photoluminescence and optical reflectivity measurements confirm the existence of the prepared trion state. This technique also prepares intermediate regimes with controlled luminescence amplitudes of the neutral and charged exciton. This effect is reversible by exposing the sample to air, indicating the change is mitigated by surface interactions with the ambient environment. This method provides a tool to modify optical emission energy and to isolate physical processes in this and other two-dimensional materials.
Effect of molecular electrical doping on polyfuran based photovoltaic cells
Authors: Yu Shuwen , Frisch Johannes , Opitz Andreas , Cohen Erez , Bendikov Michael , Koch Norbert , Salzmann Ingo
Published: May 2015

The electronic, optical, and morphological properties of molecularly p-doped polyfuran (PF) films were investigated over a wide range of doping ratio in order to explore the impact of doping in photovoltaic applications. We find evidence for integer-charge transfer between PF and the prototypical molecular p-dopant tetrafluoro-tetracyanoquinodimethane (F4TCNQ) and employed the doped polymer in bilayer organic solar cells using fullerene as acceptor. The conductivity increase in the PF films at dopant loadings ≤2% significantly enhances the short-circuit current of photovoltaic devices. For higher doping ratios, however, F4TCNQ is found to precipitate at the heterojunction between the doped donor polymer and the fullerene acceptor. Ultraviolet photoelectron spectroscopy reveals that its presence acts beneficial to the energy-level alignment by doubling the open-circuit voltage of solar cells from 0.2 V to ca. 0.4 V, as compared to pristine PF.
Note: Fiber optic transport probe for Hall measurements under light and magnetic field at low temperatures: Case study of a two dimensional electron gas
Authors: Bhadauria P. P. S. , Gupta Anurag , Kumar Pramod , Dogra Anjana , Budhani R. C.
Published: May 2015

A fiber optic based probe is designed and developed for electrical transport measurements in presence of quasi-monochromatic (360–800 nm) light, varying temperature (T = 1.8–300 K), and magnetic field (B = 0–7 T). The probe is tested for the resistivity and Hall measurements performed on a LaAlO3–SrTiO3 heterointerface system with a conducting two dimensional electron gas.
Magnetic-field-induced switchable exchange bias in NiFe film on (110) Fe3O4 with a strong uniaxial magnetic anisotropy
Authors: Dho Joonghoe
Published: May 2015

The exchange bias in a soft ferromagnetic NiFe layer coupled with a hard ferrimagnetic Fe3O4 film grown on a (110) SrTiO3 single-crystal substrate was investigated as a function of the switching magnetic field (HS) as a means to control the magnetization direction of the Fe3O4. The sign of the exchange bias was consistent with the sign of HS, indicating that the exchange coupling constant between the NiFe and (110) Fe3O4 layers was positive. Below |HS| = 1 kOe, the hysteresis behavior of the exchange bias of the soft ferromagnetic NiFe resembled the magnetic hysteresis behavior of the hard ferrimagnetic Fe3O4.
Broadband wireless radio frequency power telemetry using a metamaterial resonator embedded with non-foster impedance circuitry
Authors: Fu Guoqing , Sonkusale Sameer
Published: May 2015

Wireless powering of implantable biomedical devices and smart radio frequency identification (RFID) tags with very low profile antennas is desired. We propose a low profile electrically small antenna for near-field wireless power telemetry employing a metamaterial Split Ring Resonator (SRR) antenna. SRRs can be designed for operation over wide frequencies from RF to visible. However, they are inherently narrowband making them sensitive to component mismatch with respect to external transmit antenna. Here, we propose an embedding of a non-foster impedance circuitry into the metamaterial SRR structure that imparts conjugate negative complex impedance to this resonator antenna thereby increasing the effective bandwidth and thus overcoming the fundamental limit for efficient signal coupling. We demonstrate the concept through extensive numerical simulations and a prototype system at the board level using discrete off-the-shelf components and printed circuit SRR antenna at 500 MHz. We show that the power transfer between SRR receive antenna and the external transmit loop antenna is improved by more than 8 dB over a wide frequency band (from 525 MHz to 635 MHz), before and after non-foster circuit activation.
Alignment of graphene oxide nanostructures between microgap electrodes via dielectrophoresis for hydrogen gas sensing applications
Authors: Singh Budhi , Wang Jianwei , Rathi Servin , Kim Gil-Ho
Published: May 2015

Graphene oxide (GO) nanostructures have been aligned between conducting electrodes via dielectrophoresis (DEP) with different electrical configurations. The arrangement of ground with respect to peak-to-peak voltage (Vpp) plays a crucial role in manipulating the GO nanostructures. Grounds on both sides of the Vpp electrode give an excellent linking of GO nanostructures which is explained by scanning electron microscopy and current-voltage characteristics. A finite element method simulation explains the electric field and voltage variation profile during DEP process. The optimized aligned GO nanostructures are used as hydrogen gas sensor with a sensitivity of 6.0% for 800 ppm hydrogen gas.
Generalized permutation entropy analysis based on the two-index entropic form Sq,δ
Authors: Xu Mengjia , Shang Pengjian
Published: May 2015

Permutation entropy (PE) is a novel measure to quantify the complexity of nonlinear time series. In this paper, we propose a generalized permutation entropy (PEq,δ) based on the recently postulated entropic form, Sq,δ, which was proposed as an unification of the well-known Sq of nonextensive-statistical mechanics and Sδ, a possibly appropriate candidate for the black-hole entropy. We find that PEq,δ with appropriate parameters can amplify minor changes and trends of complexities in comparison to PE. Experiments with this generalized permutation entropy method are performed with both synthetic and stock data showing its power. Results show that PEq,δ is an exponential function of q and the power (k(δ)) is a constant if δ is determined. Some discussions about k(δ) are provided. Besides, we also find some interesting results about power law.
Detecting the phonon interference effect in Si/Ge nanocomposite by wave packets
Authors: Ju Shenghong , Liang Xingang
Published: May 2015

As the particle size in nanocomposites approaches the order of several nanometers that is comparable with the phonon wavelength, the phonon wave interference and particle scattering effect will lead to a much more complicated energy transport. This letter reports the investigation of phonon interference and scattering in Si/Ge nanocomposites by the phonon wave packet simulation. The particle size, particle layer number, and particle shape effects on the phonon transmission are considered. For both cubic and spherical particles, the phonon transmission coefficient fluctuates obviously with the increasing particle size and there are local peaks and valleys of transmission coefficient at certain particle sizes. The transmission decreases with the increasing layers of particle. The optical multi-layer transmission model can be applied to predict the transmission coefficient of Si/Ge nanocomposites with layered particles. The enhancement of thermal conductance is up to 19.1% due to the phonon interference effect.
n-type hydrogenated microcrystalline silicon/indium tin oxide back-reflector interfacial characterization for micromorph tandem solar cell applications
Authors: Kim Sunbo , Dao Vinh Ai , Lee Jaehyeong , Lee Youn-Jung , Ahn Shihyun , Yi Junsin
Published: May 2015

Back-reflectors (BRs) in hydrogenated amorphous Si (a-Si:H)/hydrogenated micro-crystalline Si (μc-Si:H) solar cells must not only have sufficient properties to efficiently retrieve the unabsorbed light to where it can be used but must also have lesser back-interfacial states, which are needed for efficient carrier collection. In this study, in order to study the effects of μc-Si:H(n)/transparent conductive oxide-BRs interfacial properties on the performance of a-Si:H/μc-Si:H tandem solar cells, indium tin oxide (ITO)-BRs films are deposited using different reactive gases (argon (Ar), Ar-hydrogen (H2), and Ar-helium (He)). A higher recombination of μc-Si:H(n)/ITO-BRs interfaces causes lower open-circuit voltage (Voc) and fill factor (FF). For ITO deposited in Ar-He reactive gas, the higher recombination at the interface of μc-Si:H(n)/ITO-BRs may be attributed to the high energetic He ion bombardment; whereas, with the use of Ar-H2 reactive gas, the higher recombination may be attributed to the blocking carrier collection caused by the higher Schottky barrier height. The highest efficiency of 12.04% (Voc: 1422 mV, short-circuit current density: 11.06 mA/cm2, FF: 76.56%) is obtained for ITO-BRs using pure Ar gas. It is worth noting that both the interface damage and the Schottky barrier can impact device performances.
Probing the failure mechanism of nanoscale LiFePO4 for Li-ion batteries
Authors: Gu Meng , Shi Wei , Zheng Jianming , Yan Pengfei , Zhang Ji-guang , Wang Chongmin
Published: May 2015

LiFePO4 is a high power rate cathode material for lithium ion battery and shows remarkable capacity retention, featuring a 91% capacity retention after 3300 cycles. In this work, we use high-resolution transmission electron microscopy and electron energy loss spectroscopy to study the gradual capacity fading mechanism of LiFePO4 materials. We found that upon prolonged electrochemical cycling of the battery, the LiFePO4 cathode shows surface amorphization and loss of oxygen species, which directly contribute to the gradual capacity fading of the battery. The finding can guide the design and improvement of LiFePO4 cathode for high-energy and high-power rechargeable battery for electric transportation.
Disrupting migration stories: reading life histories through the lens of mobility and fixity
Authors: Rogaly Ben
Published: May 2015

It has been argued that the ‘mobility turn’ is overcelebratory regarding human movement across space. Yet, critical studies of mobilities have emerged that refute this, demonstrating how various forms and aspects of mobility are bound up with unequal power relations. This paper engages with debates over migration and mobility through an in-depth analysis of three life history interviews recorded in England in 2011. The subjects of the interviews are all men in their fifties and sixties of South Asian heritage, who moved to England as minors, and who, as adults, worked in factories for at least three years. The stories in all their affectivity and sensuousness disrupt standard tropes regarding migration and contribute to our understanding of the relations between mobility, fixity, ‘race’, and class. The built-in historical perspective shows how, looking back, someone who may once have migrated across inte rnational borders does not necessarily see that as the most significant moment in their life; how someone's past moves within a nation-state may have greater significance to them than their moves into it; how people who move at one point can also be stuck, reluctantly immobile, at another; and how both the representations and materiality of mobility and fixity are imbued with, and reproduce, class inequality and racisms.
Reducing calcium and phosphorus in crossbred beef cattle diets: impacts on productive performance during the growing and finishing phase
Authors: Prados L. F. , Filho S. C. Valadares , Santos S. A. , Zanetti D. , Nunes A. N. , Costa D. R. , Mariz L. D. S. , Detmann E. , Amaral P. M. , Rodrigues F. C. , Valadares R. F. D.
Published: May 2015

Forty 3/4 Bos indicus × 1/4 Bos taurus bulls (initial bodyweight = 214 ± 4 kg; 11 ± 0.2 months) were used in the study. Four bulls were slaughtered as reference and the other 36 bulls were allowed ad libitum consumption of treatment diets following a completely randomised 3 × 3 factorial design. The design included three diet concentrations of calcium (Ca) and phosphorus (P): standard, 50% of standard, and 75% of standard and three periods of feedlot confinement: 8, 16, and 24 weeks with four bulls per treatment combination. The diets were isonitrogenous and consisted of 60 : 40 corn silage to concentrate. Dry matter intake, crude protein, ether extract, organic matter, non-fibrous carbohydrates, Ca, and P, expressed as kg/day, were greater (P < 0.05) for bulls confined for longer periods. Nutrient digestibility and average daily gain was not affected (P > 0.05) by Ca and P concentration of diet or by feedlot phase. Dressing were decreased (P < 0.05) for bulls that remained in confinement for a shorter period. The daily maintenance requirements of Ca and P were 13.66 and 21.51 mg/kg empty bodyweight, respectively, and the absorption coefficients of Ca and P were 0.70 and 0.67, respectively. We concluded that for crossbred cattle in the feedlot, dietary levels of Ca and P recommended by BR-CORTE (2010), NRC (2000), and AFRC (1991) could be reduced by 62%, 66%, and 57%, respectively, for Ca and by 14%, 15%, and 43%, respectively, for P with significant savings in costs. This study shows that Ca and P can be reduced to 1.8 and 2.2 g/kg DM respectively, in the diets for crossbred cattle in feedlot.
Neonatal testosterone exposure induces early development of follicular cysts followed by sympathetic ovarian hyperinnervation
Authors: Anesetti Gabriel , Chávez-Genaro Rebeca
Published: May 2015

This study analysed the temporal association between ovarian cyst development induced by neonatal androgenisation and sympathetic innervation. Neonatal rats (postnatal Days 1 to 5) were treated with testosterone or dihydrotestosterone and the effects were evaluated at postnatal Days 20, 40, 90 or 180. Ovulation rate, number of cystic follicles and density of sympathetic fibres were analysed. The effects of surgical denervation or gonadotrophin stimulation were also assessed. Rats exposed to testosterone showed no oestrous cycle activity and did not ovulate, maintaining a polycystic ovarian morphology at all ages studied. Also, a significant increase in ovarian density of noradrenergic fibres was detected at postnatal Days 90 and 180. Sympathectomy was unable to re-establish ovarian activity; however, human chorionic gonadotrophin stimulation was enough to induce ovulation. The impact of dihydrotestosterone on ovarian function was less noticeable, showing the coexistence of corpora lutea and cystic structures without changes in sympathetic innervation. Our findings suggest that a remodelling of ovarian sympathetic innervation occurs as a response to modifications in the pattern of follicular growth induced by testosterone. A role of sympathetic innervation in the maintenance of the polycystic condition is suggested.
Rapid molecular evolution across amniotes of the IIS/TOR network
Authors: McGaugh Suzanne E. , Bronikowski Anne M. , Kuo Chih-Horng , Reding Dawn M. , Addis Elizabeth A. , Flagel Lex E. , Janzen Fredric J. , Schwartz Tonia S.
Published: May 2015

Significance

Comparative analyses of central molecular networks uncover variation that can be targeted by biomedical research to develop insights and interventions into disease. The insulin/insulin-like signaling and target of rapamycin (IIS/TOR) molecular network regulates metabolism, growth, and aging. With the development of new molecular resources for reptiles, we show that genes in IIS/TOR are rapidly evolving within amniotes (mammals and reptiles, including birds). Additionally, we find evidence of natural selection that diversified the hormone-receptor binding relationships that initiate IIS/TOR signaling. Our results uncover substantial variation in the IIS/TOR network within and among amniotes and provide a critical step to unlocking information on vertebrate patterns of genetic regulation of metabolism, modes of reproduction, and rates of aging.
Prediction of 10-fold coordinated TiO
2
and SiO
2
structures at multimegabar pressures
Authors: Lyle Matthew J. , Pickard Chris J. , Needs Richard J.
Published: May 2015

Significance

The highest-pressure phase of TiO
2
, SiO
2
, and several other important dioxides was hitherto believed to be nine-coordinated Fe
2
P-type. We searched for low-enthalpy phases of TiO
2
using density functional theory methods, finding that the most stable form of TiO
2
at pressures above 650 GPa is a ten-coordinated structure with space group
I
4
/mmm
. TiO
2
is the well-established high-pressure model for many AX
2
compounds, and our study shows that SiO
2
should also form in the
I
4/
mmm
structure above 10 TPa. The high-pressure
I
4/
mmm
polymorph of SiO
2
is likely to be a major constituent of giant rocky planets at multiterapascal pressures, and our results call for a reformulation of the equations of state used to model them.
BAF is a cytosolic DNA sensor that leads to exogenous DNA avoiding autophagy
Authors: Kobayashi Shouhei , Koujin Takako , Kojidani Tomoko , Osakada Hiroko , Mori Chie , Hiraoka Yasushi , Haraguchi Tokuko
Published: May 2015

Significance

Rapid detection of invasion of exogenous materials and subsequent responses are important for living organisms to survive hazards, such as pathogen infection. Understanding cellular responses against exogenous DNA provides clues not only for controlling pathogen infections that bring exogenous DNA into host cells, but also for designing efficient DNA delivery vectors for transgene expression. Here, by monitoring the invasion of exogenous DNA-coated polystyrene beads into living cells, we show that barrier-to-autointegration factor detects exogenous DNA immediately after its appearance at endosome breakdown and plays a role in DNA avoiding autophagy. These findings provide new insights into the mechanisms by which a cell detects and responds to exogenous double-stranded DNA.
Structural rearrangements in the phage head-to-tail interface during assembly and infection
Authors: Chaban Yuriy , Lurz Rudi , Brasilès Sandrine , Cornilleau Charlène , Karreman Matthia , Zinn-Justin Sophie , Tavares Paulo , Orlova Elena V.
Published: May 2015

Significance

Stable genome maintenance inside viral particles and its controlled delivery to the host are critical for virus infection. We report cryoEM structures of a tailed bacterial virus genome gatekeeper mimicking the states before and after DNA release. The subnanometer resolution allowed precise fitting of individual protein components. We found concerted structural rearrangements in the portal through which DNA traffic occurs. DNA is locked in a capsid by gp16 loops that close the channel by an allosteric mechanism. Gp16 appears to open by a diaphragm-like motion, allowing the genome to exit the capsid through the tail tube to the host cell. We propose a molecular mechanism by which the largest group of viruses on Earth controls its DNA movement.
The economic policies of Italian social democracy in the post-war period (1945–1962)
Authors: Granata Mattia
Published: May 2015

In post-war Italy, ‘reformism’ has been ignored by many, wished for by some, and pursued by only a few. While it was a beacon for the major progressive political forces of Western countries, in Italy this idea was for a long time considered an ‘impossible’ vision. Even when there have been attempts to trace its development, explain the reasons for its failure, or reassess some of its merits, it has been sought everywhere except where it should actually be located: within those parties which defined themselves and considered themselves reformist, for example within the social democrat tradition. For a long period on the political level, Italian social democracy was squeezed between the formidable Catholic tradition and a powerful Communist culture. These pressures contributed to its negation, on both a historiographical and a political level, including a denial of the features of modernity in its development, or at the very least the obscuring of its achievements. Italian reformism, whether a ‘possible’ or ‘impossible’ option, has thus been removed from consideration, both in politics and in historiography.
Temporal predictability enhances judgements of causality in elemental causal induction from both observation and intervention
Authors: Greville W. James , Buehner Marc J.
Published: May 2015

When the temporal interval or delay separating cause and effect is consistent over repeated instances, it becomes possible to predict when the effect will follow from the cause, hence temporal predictability serves as an appropriate term for describing consistent cause-effect delays. It has been demonstrated that in instrumental action-outcome learning tasks, enhancing temporal predictability by holding the cause-effect interval constant elicits higher judgements of causality compared to conditions involving variable temporal intervals. Here, we examine whether temporal predictability exerts a similar influence when causal learning takes place through observation rather than intervention through instrumental action. Four experiments demonstrated that judgements of causality were higher when the temporal interval was constant than when it was variable, and that judgements declined with increasing variability. We further found that this beneficial effect of predictability was stronger in situations where the effect base-rate was zero (Experiments 1 and 3). The results therefore clearly indicate that temporal predictability enhances impressions of causality, and that this effect is robust and general. Factors that could mediate this effect are discussed.
Common magnitude representation of fractions and decimals is task dependent
Authors: Zhang Li , Fang Qiaochu , Gabriel Florence C. , Szűcs Denes
Published: May 2015

Although several studies have compared the representation of fractions and decimals, no study has investigated whether fractions and decimals, as two types of rational numbers, share a common representation of magnitude. The current study aimed to answer the question of whether fractions and decimals share a common representation of magnitude and whether the answer is influenced by task paradigms. We included two different number pairs, which were presented sequentially: fraction–decimal mixed pairs and decimal–fraction mixed pairs in all four experiments. Results showed that when the mixed pairs were very close numerically with the distance 0.1 or 0.3, there was a significant distance effect in the comparison task but not in the matching task. However, when the mixed pairs were further apart numerically with the distance 0.3 or 1.3, the distance effect appeared in the matching task regardless of the specific stimuli. We conclude that magnitudes of fractions and decimals can be represented in a common manner, but how they are represented is dependent on the given task. Fractions and decimals could be translated into a common representation of magnitude in the numerical comparison task. In the numerical matching task, fractions and decimals also shared a common representation. However, both of them were represented coarsely, leading to a weak distance effect. Specifically, fractions and decimals produced a significant distance effect only when the numerical distance was larger.
Double centraliser property and morphism categories
Authors: Gao Nan , Koenig Steffen
Published: May 2015

Given a ring

A
A

and an idempotent

e
∈
A

e \in A

, double centraliser property on the bimodule

e
A

eA

is characterised in terms of equivalences of additive categories, which are related to morphism categories. The results and methods then are applied to gendo-Gorenstein algebras.
An ELMO2-RhoG-ILK network modulates microtubule dynamics
Authors: Jackson Bradley C. , Ivanova Iordanka A. , Dagnino Lina
Published: May 2015

ELMO2 belongs to a family of scaffold proteins involved in phagocytosis and cell motility. ELMO2 can simultaneously bind integrin-linked kinase (ILK) and RhoG, forming tripartite ERI complexes. These complexes are involved in promoting β1 integrin–dependent directional migration in undifferentiated epidermal keratinocytes. ELMO2 and ILK have also separately been implicated in microtubule regulation at integrin-containing focal adhesions. During differentiation, epidermal keratinocytes cease to express integrins, but ERI complexes persist. Here we show an integrin-independent role of ERI complexes in modulation of microtubule dynamics in differentiated keratinocytes. Depletion of ERI complexes by inactivating the Ilk gene in these cells reduces microtubule growth and increases the frequency of catastrophe. Reciprocally, exogenous expression of ELMO2 or RhoG stabilizes microtubules, but only if ILK is also present. Mechanistically, activation of Rac1 downstream from ERI complexes mediates their effects on microtubule stability. In this pathway, Rac1 serves as a hub to modulate microtubule dynamics through two different routes: 1) phosphorylation and inactivation of the microtubule-destabilizing protein stathmin and 2) phosphorylation and inactivation of GSK-3β, which leads to the activation of CRMP2, promoting microtubule growth. At the cellular level, the absence of ERI species impairs Ca2+-mediated formation of adherens junctions, critical to maintaining mechanical integrity in the epidermis. Our findings support a key role for ERI species in integrin-independent stabilization of the microtubule network in differentiated keratinocytes.
Control and restructuring in Greek
Authors: Grano Thomas
Published: May 2015

The functional restructuring approach to exhaustive control is extended in this chapter to modern Greek. The chapter argues that in Greek, exhaustive control predicates instantiate monoclausal configurations whereas partial control predicates instantiate biclausal configurations. The key observation motivating this conclusion is that exhaustive control predicates in Greek impose severe restrictions on the range of tense, aspect, and agreement inflections the embedded verb may take, and independent support comes from emphatic polarity item licensing and inverse scope. The proposal entails two points of cross-linguistic morphosyntactic variation: first, some languages are like Greek in not distinguishing morphologically between nonpast and tenseless verb forms, whereas other languages are like English in making such a distinction. Second, some languages are like Greek in that Agr co-occurs with each verb in the clause, whereas other languages are like English in that Agr occurs just once per finite clause.
Subjectivity in Inductive Inference
Authors: Gilboa Itzhak , Samuelson Larry , Schmeidler David
Published: May 2015

Inductive inference is the art of selecting theories based on observations. A fundamental principle is that one should only consider theories that have not been refuted by the data. But how should people choose among the theories that best match the data? People often bring subjective criteria to bear in making this choice, selecting theories that seem a priori reasonable, intuitive, simple, elegant, familiar, or that satisfy a variety of other considerations. This chapter explains how and why subjective criteria are essential to effective reasoning. It concludes that inference cannot effectively be based on objective arguments alone—simply observing that one theory fits the data better than another is not sufficient to prefer the former to the latter. Instead, one must also argue that the candidate theory fares well in terms of consistently applied subjective auxiliary criteria.
Shattering Lives: The Normalisation of Deportation
Authors: Dembour Marie-Bénédicte
Published: May 2015

This chapter discusses the Berrehab v. the Netherlands judgment of 1988 and subsequent rulings regarding the expulsion, generally after criminal conviction, of a long-settled migrant. In this case law, the main question for the European Court was whether the expulsion has actually been or would be in violation of Article 8 of the European Convention on Human Rights (ECHR). It shows that the Court prevaricated on this question and was unable to come with firm principles, thus illustrating clearly the presence of various currents and undercurrents within it.
Migrants, Not Criminals: The Continual Elaboration of Strong Human Rights Norms in the Inter-American System
Authors: Dembour Marie-Bénédicte
Published: May 2015

This chapter discusses the Vélez Loor v. Panama judgment of 2010, in which the Inter-American Court identified a number of stringent guarantees required for the use of immigration detention, which it only allows as a last resort. It shows that the take of the European Court on immigration detention is very different, and characterises the approach of the Inter-American Court as realist, humanist, and thorough. While the European Court displays the same characteristics in cases when it reaches a ‘tipping point’, this does not mean that the Strasbourg case law on children’s detention is strong and principled. The chapter ends by returning to Vélez Loor. It explains that the judgment has not been a panacea for the victim and that the Court refrained from taking up the representatives’ invitation to understand what had happened to Mr Vélez Loor by reference to a context of general discrimination against migrants.
Introduction
Authors: Toropov Alexey A. , Shubina Tatiana V.
Published: May 2015

This chapter describes the long history of plasmonics, starting from the Lycurgus cup and stained glass windows that rely on plasmonic properties of tiny metallic particles and Wood’s anomalies in light reflection from a metal diffraction grating. The chapter outlines the fundamental contributions to the scientific background of plasmonics of such outstanding scientists as Zenneck, Sommerfeld, Mie, Fano, Van der Pol, Fock, Purcell, Ritchie, and many others, who developed the concepts of surface plasmon polaritons and localized surface plasmons, as well as the foundations of the resonant interaction of light with conductors. The successive discovery of the phenomenon of surface enhanced Raman scattering (SERS) stimulated applications of plasmonic effects in modern optical spectroscopy. It is emphasized that most recent breakthroughs of plasmonics essentially rely on the development of nanotechnology and nanometrology. Apart from a short historical survey, the chapter describes the scope of the book and defines the potential readership.
Electrodynamics of Metal Structures
Authors: Toropov Alexey A. , Shubina Tatiana V.
Published: May 2015

This chapter summarizes the fundamental facts and concepts of classical electromagnetism, applied in successive chapters to the consideration of the electronic plasma excitations supported by various metal and metal–semiconductor nanostructures. The chapter outlines the basic principles of electrodynamics, the Drude theory describing dielectric function of free electrons, propagation of surface plasmon polaritons at a plane interface between a metal and an insulator, and excitation of localized surface plasmons in metal particles. The quasi-static approximation is represented for the general case of ellipsoidal particles, whereas the exact Mie theory is employed to define plasmonic excitations in conducting spheres. Thus, the goal of the chapter is to give a basic overview of the plasmonic effects and to introduce notations, conventions, and units of electrodynamics that are consistently used throughout the rest of the book.
Electronic Excitations in Semiconductors
Authors: Toropov Alexey A. , Shubina Tatiana V.
Published: May 2015

This chapter presents a general description and calculation of the electronic band structures in III–V and II–VI semiconductors with both zinc-blende and wurtzite crystal structures. Relevant concepts are introduced, including the Bloch’s theorem and the symmetry theory based on the mathematics of group representations. Analytical expressions for the band dispersion around high-symmetry points of the Brillouin zone are obtained in the framework of the k⋅p theory. Kane and Luttinger–Kohn models are represented for the zinc-blende crystal structure, while the electronic band structure of the wurtzite-type semiconductors is defined within the Kane model and the model developed by Rashba, Sheka, and Pikus. Effects of elastic strain on the band structures are described. The basic principles of the band theory in crystals, outlined in this chapter, are employed in following chapters to define optical processes in semiconductor and metal–semiconductor nanostructures.
Conducting Materials
Authors: Toropov Alexey A. , Shubina Tatiana V.
Published: May 2015

This chapter covers the optical and electronic properties of available conducting materials capable of supporting plasmonic excitations. Described here are noble metals and polyvalent metals (gold, silver, indium, and aluminium), degenerate semiconductors, doped oxides and semimetals, as well as graphene. The area of applicability of the considered materials for plasmonics is determined on the basis of their complex dielectric functions defined by both interband and intraband transitions. The properties of metal–dielectric composites are treated in the framework of the generalized Maxwell–Garnett approximation. The influence on fundamental parameters of semiconductor compounds of their deviation from stoichiometry is discussed in terms of the empirical tight binding theory. Where possible, the chapter provides explicit expressions and plots defining the spectra of complex dielectric functions and other important characteristics.
Frontiers in Plasmonics Applications
Authors: Toropov Alexey A. , Shubina Tatiana V.
Published: May 2015

This chapter covers a wide range of promising applications based on plasmonic effects in nanostructures comprising conductors and semiconductors. The ultimate goal of the chapter is to present the most amazing results yet obtained and to reveal existing bottlenecks in the field of the metal–semiconductor plasmonics. The list of most appealing advances described here includes achievement of the strong coupling regime in plasmonic cavities with both organic and inorganic semiconductors, demonstration of the room-temperature operation of plasmonic nanolasers and single photon sources, preservation of the non-classical statistics of single photons during energy transfer by surface plasmon polaritons, employment of metal–semiconductor composites as active media of plasmonic solar cells, efficient wavefront engineering in the quantum cascade lasers with integrated plasmonic structures, and tuning the plasmon frequency in metallic structures by gated graphene in a broad frequency range. The presented discussions rely on the results obtained in all previous chapters.
An Introduction to the Theory of Mechanism Design
Authors: Börgers Tilman , Krähmer Daniel , Strausz Roland
Published: May 2015

What is the best way to auction an asset? How should a group of people organize themselves to ensure the best provision of public goods? How should exchanges be organized? This book addresses these questions and more through an exploration of the economic theory of mechanism design. Mechanism design is reverse game theory. Whereas game theory takes the rules of the game as a given and makes predictions about the behavior of strategic players, the theory of mechanism design goes a step further and selects the optimal rules of the game. A relatively new economic theory, mechanism design studies the instrument itself as well as the results of the instrument. This book provides explanations of classic results in the theory of mechanism design, such as Myerson's theorem on expected revenue maximizing auctions, Myerson and Satterthwaite's theorem on the impossibility of ex post efficient bilateral trade with asymmetric information, and Gibbard and Satterthwaite's theorem on the non-existence of dominant strategy voting mechanisms. It also provides an examination of the frontiers of current research in the area.
Assembly bias & redshift–space distortions: impact on cluster dynamics tests of general relativity
Authors: Hearin Andrew P.
Published: May 2015

The redshift–space distortion (RSD) of galaxies surrounding massive clusters is emerging as a promising testbed for theories of modified gravity. Conventional applications of this method rely upon the assumption that the velocity field in the cluster environment is uniquely determined by the cluster mass profile. Yet, real dark matter haloes in N-body simulations are known to violate the assumption that virial mass determines the configuration space distribution, an effect known as assembly bias. In this Letter, I show that assembly bias in simulated dark matter haloes also manifests in velocity space. In the 1–10 Mpc environment surrounding a cluster, high-concentration ‘tracer’ haloes exhibit a 10–20 per cent larger pairwise-velocity dispersion profile relative to low-concentration tracer haloes of the same mass. This difference is comparable to the size of the RSD signal predicted by f(R) models designed to account for the cosmic acceleration. I use the age matching technique to study how colour-selection effects may influence the cluster RSD signal, finding a ∼10 per cent effect due to redder satellites preferentially occupying higher mass haloes, and a ∼5 per cent effect due to assembly-biased colours of centrals. In order to use cluster RSD measurements to robustly constrain modified gravity, we likely will need to develop empirical galaxy formation models more sophisticated than any in the current literature.