bluuebunny/crossref_metadata_2025_split huggingface dataset:
Optomechanical interface for probing matter-wave coherence
Authors: Xuereb André , Ulbricht Hendrik , Paternostro Mauro 
Published: November 2013

AbstractWe combine matter-wave interferometry and cavity optomechanics to propose a coherent matter–light interface based on mechanical motion at the quantum level. We demonstrate a mechanism that is able to transfer non-classical features imprinted on the state of a matter-wave system to an optomechanical device, transducing them into distinctive interference fringes. This provides a reliable tool for the inference of quantum coherence in the particle beam. Moreover, we discuss how our system allows for intriguing perspectives, paving the way to the construction of a device for the encoding of quantum information in matter-wave systems. Our proposal, which highlights previously unforeseen possibilities for the synergistic exploitation of these two experimental platforms, is explicitly based on existing technology, available and widely used in current cutting-edge experiments.
Design of broadband Class E power amplifier in continuous operation modes
Authors: Gao Zhong , Liu Chang , Guo Guiliang , Chen Hua , Luo Chao , Han Jingyu , Zhang Lijun , Yan Yuepeng 
Published: November 2013

Theoretically, constant output power and high DC‐to‐RF efficiency cannot be simultaneously achieved by a broadband Class E power amplifier (PA) even if the load network could provide the accurate impedance desired at each frequency point. Such a problem is solved with the presented concept of continuous Class E modes. New demands on the load and corresponding load network topology are discussed to provide a theoretical basis. To verify the feasibility, a prototype PA in TSMC 0.18 μm CMOS process is also presented. In the simulation, it exhibits a maximum output power of 18.7 dBm, a power added efficiency of 64–80% and an output power flattening of 0.5 dB in the frequency range from 360 to 610 M (52% of the central frequency). A comparison between it and a broadband parallel Class E PA implemented under the same conditions is also given.
Gain enhanced pattern reconfigurable planar Yagi‐Uda antenna on coplanar structure
Authors: Raman S. , Timmons N. , Morrison J. 
Published: November 2013

A gain enhanced planar Yagi‐Uda antenna with pattern reconfiguration is presented. The prototype provides an omnidirectional pattern as well as a high‐gain directive pattern, which can be reconfigured on two orthogonal planes. For the first time, the principle of a Yagi‐Uda antenna combined with pattern reconfiguration is implemented without complexity on a planar prototype. The pattern reconfiguration is achieved by alternately switching the driven and reflector elements of the Yagi‐Uda antenna. The prototype concept was simulated using CST Microwave Studio, fabricated on a substrate of dielectric constant 4.4 and tested using an R&S ZVB8 network analyser. The gain variation with the reflector and director parameters is also analysed and presented.
Application of synchronised phasor measurements to wide‐area fault diagnosis and location
Authors: Salehi‐Dobakhshari Ahmad , Ranjbar Ali Mohammad 
Published: November 2013

This study introduces a novel approach to power system fault diagnosis by synchronised phasor measurements. Conventionally, faults are diagnosed through the status of protective relays and circuit breakers which are activated following a fault. However, the hidden failures of the protection system has itself often been among the main suspects of partial or widespread blackouts. This study proposes an alternative fault diagnosis approach independent of the function of the protection system. An analytical method is introduced for power system fault diagnosis using dispersed synchronised measurements and bus impedance matrix (Zbus). Fault inception is first detected by local phasor measurement units (PMUs). Fault diagnosis is then carried out in a hierarchical manner so that first the faulted zone of the system is diagnosed, next the faulted line in the faulted zone is diagnosed and finally the fault point along the diagnosed line is located by gradient descent. The proposed method is applied to the WSCC 9‐bus, where fault incidents on all of the transmission lines are examined. Moreover, the proposed method is successfully applied to the IEEE 118‐bus test system consisting of 28 PMUs, which demonstrates successful fault diagnosis and location for a large‐scale power system despite the limited coverage of PMUs.
Design, microfabrication and measurement of cooling arm for fusion energy source application
Authors: Jiang Shui‐Dong , Liu Jing‐Quan , Yang Bin , Zhu Hong‐Ying , Yang Chun‐Sheng 
Published: November 2013

The novel cooling arm plays an important role in thermal transfer in the production process of fusion energy. Its structure is designed and simulated by a finite element method. The result shows that the structure with two branches can obtain a temperature difference less than 1 mK among the grip surfaces of all the fingers. A (111) crystal orientation silicon is deployed to fabricate the cooling arm, because of its isotropic Young's modulus. The thermal conductivity of this material is measured by a Gifford‐McMahon (GM) cooler. The result shows it has large thermal conductivity at cryogenic temperature, which excellently contributes to heat transfer. The cooling arm is obtained by a microfabrication process. With a uniform pattern width mask and optimised deep reactive ion etching process recipe, a nearly 90° vertical sidewall is obtained. The temperature distribution of the cooling arm is also measured by a GM cooler, and the result shows that the maximum temperature deviation is 0.48 mK among the 16 fingers. There is a good agreement between finite element analysis and the experimental result.
Electrochemical detection of methanol by platinum/carbon nanotubes nanocomposites synthesised via hydrogen plasma reduction process
Authors: Xu Jielin , Wang Shenggao , Du Zurong , Zhu Jinlong , Liu Yi , Zhang Wei , Wang Jianhua 
Published: November 2013

Platinum (Pt)/carbon nanotube (CNTs) nanocomposites were fabricated on the basis of Pt precursors reduced by hydrogen plasma generated by microwave process. The Pt nanoparticles were uniformly dispersed on multi‐walled CNTs. Such nanocomposites exhibit remarkable catalytic performance towards the oxidation of methanol. The concentration of methanol was determined by a chronoamperometric method by using the Pt/CNTs modified glass carbon electrode (Pt/CNTs/GCE) at an oxidation potential of 0.7 V against the saturated calomel electrode. The Pt/CNTs/GCE showed a good performance for detecting methanol because of the unique properties of CNTs which increased the active surface area of the electrode and accelerated the electro transfer. The linear detection range of methanol was determined to be from 2.0 × 10−4 to 10.0 M in two slopes with a detection limit 5 × 10−5M at a signal‐to‐noise ratio of 3. The performance of the Pt/CNTs/GCE in terms of stability, linear range and detection limit shows its potential application for methanol detection.
Genetic resources and conservation challenges under the threat of climate change.
Authors: Ford-Lloyd B. , Engels J. M. M. , Jackson M. 
Published: November 2013

Abstract

This chapter describes and discusses some of the initiatives and developments that make the world better prepared to respond to climate change in terms of plant genetic resources (PGRs). A broad overview is provided of important issues concerning conservation and use of PGRs, including conservation approaches, strategies and responses that become more relevant under the threat of climate change. An enormous amount of crop germplasm and wild relatives is conserved in genebanks around the world, as well as in situ. Although not all this conserved germplasm is equally characterized and evaluated, there is sufficient documented germplasm available to plant breeders that can be used to tackle the growing threat of global climate change.
Climate projections.
Authors: Betts R. A. , Hawkins E. 
Published: November 2013

Abstract

This chapter discusses the following topics: the concept and drivers of climate change and variability; climate models for estimating future climate variations and changes; long-term climate projections (temperature, precipitation, different patterns of regional climate change at specific global warming levels, implications of uncertainties in CO2 concentrations for a given level of global warming, changes in weather extremes); near-term climate projections; and emerging research on the AR4 Projections.
International mechanisms for conservation and use of genetic resources.
Authors: Moore G. , Hawtin G. 
Published: November 2013

Abstract

This chapter explores briefly the various international mechanisms for the conservation and use of genetic resources and how they have developed. Then it looks more closely at the Treaty (International Treaty on Plant Genetic Resources for Food and Agriculture) and explore ways in which its Contracting Parties, acting through the Governing Body of the Treaty, may be able to improve its implementation.
Poverty, livestock and food security in developing countries.
Authors: Turk J. M. 
Published: November 2013

Abstract
Poverty, livestock and food security are linked directly and indirectly. Insufficient capital to purchase enough food is a direct linkage, but even wealthy people can be poorly nourished if the nutritional quality of foods they consume is unbalanced. The most recent FAO State of Food Insecurity in the World report highlights that between 2010 and 2012 chronic undernourishment affected nearly 870 million people in the developing countries or 12.5% of the global population, the majority of whom live in developing countries. However, poverty is not necessarily equated with the level of malnutrition, especially that of children. There is a likelihood that higher levels of malnutrition among children would be found in lower income countries, but proportions of malnourishment may not always be associated with a country's economic status. Malnutrition is caused by a lack of sufficient calories and proteins from animal source foods (ASFs) and other sources, as well as micronutrient (vitamin and mineral) deficiency. Malnutrition and undernutrition severely affect children's physical and intellectual development. In developing countries, both urban and rural populations keep livestock for many reasons. Livestock value is measured economically, socioculturally, environmentally and nutritionally. ASFs contain some of the most important micronutrients needed by humans, and diverse diets that include ASF contain greater energy and higher protein digestibility than plants. For example, ASF protein digestibility is approximately 94%, whereas digestibility of bean protein is 78% and that of whole wheat 86%. However, rural populations that produce livestock do not necessarily benefit from adequate ASF consumption.
Genetic robustness and functional evolution of gene duplicates
Authors: Plata Germán , Vitkup Dennis 
Published: November 2013

AbstractGene duplications are a major source of evolutionary innovations. Understanding the functional divergence of duplicates and their role in genetic robustness is an important challenge in biology. Previously, analyses of genetic robustness were primarily focused on duplicates essentiality and epistasis in several laboratory conditions. In this study, we use several quantitative data sets to understand compensatory interactions between Saccharomyces cerevisiae duplicates that are likely to be relevant in natural biological populations. We find that, owing to their high functional load, close duplicates are unlikely to provide substantial backup in the context of large natural populations. Interestingly, as duplicates diverge from each other, their overall functional load is reduced. At intermediate divergence distances the quantitative decrease in fitness due to removal of one duplicate becomes smaller. At these distances, yeast duplicates display more balanced functional loads and their transcriptional control becomes significantly more complex. As yeast duplicates diverge beyond 70% sequence identity, their ability to compensate for each other becomes similar to that of random pairs of singletons.
Establishment of active chromatin structure at enhancer elements by mixed-lineage leukemia 1 to initiate estrogen-dependent gene expression
Authors: Jeong Kwang Won , Andreu-Vieyra Claudia , You Jueng Soo , Jones Peter A. , Stallcup Michael R. 
Published: November 2013

Abstract
A number of genome-wide analyses have revealed that estrogen receptor α binding to and regulation of its target genes correlate with binding of FOXA1, a pioneer factor, to nearby DNA sites in MCF-7 breast cancer cells. The enhancer element-specific histone H3K4me1/2 mark is enriched at the specific FOXA1/ERα recruitment sites in chromatin, but the mechanism by which these enhancer marks are established in chromatin before hormone treatment is unclear. Here, we show that mixed-lineage leukemia 1 (MLL1) protein is a key determinant that maintains permissive chromatin structure of the TFF1 enhancer region. MLL1 occupies the TFF1 enhancer region and methylates H3K4 before hormone stimulation. In vitro, MLL1 binds directly to the CpG-rich region of the TFF1 enhancer, and its binding is dependent on hypomethylation of DNA. Furthermore, the depletion of MLL1 in MCF-7 cells results in a dramatic decrease of chromatin accessibility and recruitment of FOXA1 and ERα to the enhancer element. Our study defines the mechanism by which MLL1 nucleates histone H3K4 methylation marks in CpG-enriched regions to maintain permissive chromatin architecture and allow FOXA1 and estrogen receptor α binding to transcriptional regulatory sites in breast cancer cells.
Intramolecular binding mode of the C-terminus ofEscherichia colisingle-stranded DNA binding protein determined by nuclear magnetic resonance spectroscopy
Authors: Shishmarev Dmitry , Wang Yao , Mason Claire E. , Su Xun-Cheng , Oakley Aaron J. , Graham Bim , Huber Thomas , Dixon Nicholas E. , Otting Gottfried 
Published: November 2013

AbstractSingle-stranded DNA (ssDNA) binding protein (SSB) is an essential protein to protect ssDNA and recruit specific ssDNA-processing proteins. Escherichia coli SSB forms a tetramer at neutral pH, comprising a structurally well-defined ssDNA binding domain (OB-domain) and a disordered C-terminal domain (C-domain) of ∼64 amino acid residues. The C-terminal eight-residue segment of SSB (C-peptide) has been shown to interact with the OB-domain, but crystal structures failed to reveal any electron density of the C-peptide. Here we show that SSB forms a monomer at pH 3.4, which is suitable for studies by high-resolution nuclear magnetic resonance (NMR) spectroscopy. The OB-domain retains its 3D structure in the monomer, and the C-peptide is shown by nuclear Overhauser effects and lanthanide-induced pseudocontact shifts to bind to the OB-domain at a site that harbors ssDNA in the crystal structure of the SSB–ssDNA complex. 15N relaxation data demonstrate high flexibility of the polypeptide segment linking the C-peptide to the OB-domain and somewhat increased flexibility of the C-peptide compared with the OB-domain, suggesting that the C-peptide either retains high mobility in the bound state or is in a fast equilibrium with an unbound state.
Quantifying the role of steric constraints in nucleosome positioning
Authors: Rube H. Tomas , Song Jun S. 
Published: November 2013

Abstract
Statistical positioning, the localization of nucleosomes packed against a fixed barrier, is conjectured to explain the array of well-positioned nucleosomes at the 5′ end of genes, but the extent and precise implications of statistical positioning in vivo are unclear. We examine this hypothesis quantitatively and generalize the idea to include moving barriers as well as nucleosomes actively packed against a barrier. Early experiments noted a similarity between the nucleosome profile aligned and averaged across genes and that predicted by statistical positioning; however, we demonstrate that aligning random nucleosomes also generates the same profile, calling the previous interpretation into question. New rigorous results reformulate statistical positioning as predictions on the variance structure of nucleosome locations in individual genes. In particular, a quantity termed the variance gradient, describing the change in variance between adjacent nucleosomes, is tested against recent high-throughput nucleosome sequencing data. Constant variance gradients provide support for generalized statistical positioning in ∼50% of long genes. Genes that deviate from predictions have high nucleosome turnover and cell-to-cell gene expression variability. The observed variance gradient suggests an effective nucleosome size of 158 bp, instead of the commonly perceived 147 bp. Our analyses thus clarify the role of statistical positioning in vivo.
Phylogenetically related and ecologically similar carnivores harbour similar parasite assemblages
Authors: Huang Shan , Bininda‐Emonds Olaf R. P. , Stephens Patrick R. , Gittleman John L. , Altizer Sonia 
Published: November 2013

SummaryMost parasites infect multiple hosts, but what factors determine the range of hosts a given parasite can infect? Understanding the broad scale determinants of parasite distributions across host lineages is important for predicting pathogen emergence in new hosts and for estimating pathogen diversity in understudied host species.In this study, we used a new data set on 793 parasite species reported from free‐ranging populations of 64 carnivore species to examine the factors that influence parasite sharing between host species.Our results showed that parasites are more commonly shared between phylogenetically related host species pairs. Additionally, host species with higher similarity in biological traits and greater geographic range overlap were also more likely to share parasite species.Of three measures of phylogenetic relatedness considered here, the number divergence events that separated host species pairs most strongly influenced the likelihood of parasite sharing. We also showed that viruses and helminths tend to infect carnivore hosts within more restricted phylogenetic ranges than expected by chance.Overall, our results underscore the importance of host evolutionary history in determining parasite host range, even when simultaneously considering other factors such as host ecology and geographic distribution.
Towards an energetic landscape: broad‐scale accelerometry in woodland caribou
Authors: Mosser Anna A. , Avgar Tal , Brown Glen S. , Walker C. Spencer , Fryxell John M. 
Published: November 2013

Summary

Energetic balance is a central driver of individual survival and population change, yet estimating energetic costs in free‐ and wide‐ranging animals presents a significant challenge. Animal‐borne activity monitors (using accelerometer technology) present a promising method of meeting this challenge and open new avenues for exploring energetics in natural settings.

To determine the behaviours and estimated energetic costs associated with a given activity level, three captive reindeer (Rangifer tarandus tarandus) at the Toronto Zoo were fitted with collars and observed for 53 h. Activity patterns were then measured over 13 months for 131 free‐ranging woodland caribou (R. t. caribou) spanning 450 000 km2 in northern Ontario. The captive study revealed a positive but decelerating relationship between activity level and energetic costs inferred from previous behavioural studies.

Field‐based measures of activity were modelled against individual displacement, vegetation abundance (Normalized Difference Vegetation Index), snow depth and temperature, and the best fit model included all parameters and explained over half of the variation in the data. Individual displacement was positively related to activity levels, suggesting that broad differences in energetic demands are influenced by variation in movement rates. After accounting for displacement, activity was highest at intermediate levels of vegetation abundance, presumably due to foraging behaviour. Snow depth, probably associated with digging for winter forage, moderately increased activity. Activity levels increased significantly at the coldest winter temperatures, suggesting the use of behavioural thermoregulation by caribou. These interpretations of proximate causal factors should be regarded as hypotheses subject to validation under normal field conditions.

These results illustrate the landscape characteristics that increase energetic demands for caribou and confirm the great potential for the use of accelerometry in studies of animal energetics.
Natural malaria infection reduces starvation resistance of nutritionally stressed mosquitoes
Authors: Lalubin Fabrice , Delédevant Aline , Glaizot Olivier , Christe Philippe 
Published: November 2013

SummaryIn disease ecology, there is growing evidence that environmental quality interacts with parasite and host to determine host susceptibility to an infection. Most studies of malaria parasites have focused on the infection costs incurred by the hosts, and few have investigated the costs on mosquito vectors. The interplay between the environment, the vector and the parasite has therefore mostly been ignored and often relied on unnatural or allopatricPlasmodium/vector associations.Here, we investigated the effects of natural avian malaria infection on both fecundity and survival of field‐caught femaleCulex pipiensmosquitoes, individually maintained in laboratory conditions. We manipulated environmental quality by providing mosquitoes with different concentrations of glucose‐feeding solution prior to submitting them to a starvation challenge. We used molecular‐based methods to assess mosquitoes’ infection status.We found that mosquitoes infected withPlasmodiumhad lower starvation resistance than uninfected ones only under low nutritional conditions. The effect of nutritional stress varied with time, with the difference of starvation resistance between optimally and suboptimally fed mosquitoes increasing from spring to summer, as shown by a significant interaction between diet treatment and months of capture. Infected and uninfected mosquitoes had similar clutch size, indicating no effect of infection on fecundity.Overall, this study suggests that avian malaria vectors may sufferPlasmodiuminfection costs in their natural habitat, under certain environmental conditions. This may have major implications for disease transmission in the wild.