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Showing papers by "University of St Andrews published in 2014"


Journal ArticleDOI
TL;DR: MaNGA (Mapping Nearby Galaxies at Apache Point Observatory) as mentioned in this paper employs dithered observations with 17 fiber-bundle integral field units that vary in diameter from 12'' (19 fibers) to 32'' (127 fibers).
Abstract: We present an overview of a new integral field spectroscopic survey called MaNGA (Mapping Nearby Galaxies at Apache Point Observatory), one of three core programs in the fourth-generation Sloan Digital Sky Survey (SDSS-IV) that began on 2014 July 1. MaNGA will investigate the internal kinematic structure and composition of gas and stars in an unprecedented sample of 10,000 nearby galaxies. We summarize essential characteristics of the instrument and survey design in the context of MaNGA's key science goals and present prototype observations to demonstrate MaNGA's scientific potential. MaNGA employs dithered observations with 17 fiber-bundle integral field units that vary in diameter from 12'' (19 fibers) to 32'' (127 fibers). Two dual-channel spectrographs provide simultaneous wavelength coverage over 3600-10300 A at R ~ 2000. With a typical integration time of 3 hr, MaNGA reaches a target r-band signal-to-noise ratio of 4-8 (A–1 per 2'' fiber) at 23 AB mag arcsec–2, which is typical for the outskirts of MaNGA galaxies. Targets are selected with M * 109 M ☉ using SDSS-I redshifts and i-band luminosity to achieve uniform radial coverage in terms of the effective radius, an approximately flat distribution in stellar mass, and a sample spanning a wide range of environments. Analysis of our prototype observations demonstrates MaNGA's ability to probe gas ionization, shed light on recent star formation and quenching, enable dynamical modeling, decompose constituent components, and map the composition of stellar populations. MaNGA's spatially resolved spectra will enable an unprecedented study of the astrophysics of nearby galaxies in the coming 6 yr.

1,104 citations


Journal ArticleDOI
18 Apr 2014-Science
TL;DR: This work analyzes 100 time series from biomes across Earth to ask how diversity within assemblages is changing through time and detects systematic loss of α diversity, but community composition changed systematically through time, in excess of predictions from null models.
Abstract: The extent to which biodiversity change in local assemblages contributes to global biodiversity loss is poorly understood. We analyzed 100 time series from biomes across Earth to ask how diversity within assemblages is changing through time. We quantified patterns of temporal α diversity, measured as change in local diversity, and temporal β diversity, measured as change in community composition. Contrary to our expectations, we did not detect systematic loss of α diversity. However, community composition changed systematically through time, in excess of predictions from null models. Heterogeneous rates of environmental change, species range shifts associated with climate change, and biotic homogenization may explain the different patterns of temporal α and β diversity. Monitoring and understanding change in species composition should be a conservation priority.

990 citations


Journal ArticleDOI
TL;DR: The unified mechanism shows that low-donor-number solvents are likely to lead to premature cell death, and that the future direction of research for lithium-oxygen batteries should focus on the search for new, stable, high-donour-number electrolytes, because they can support higher capacities and can better sustain discharge.
Abstract: The mechanism of O2 reduction in aprotic solvents is important for the operation of Li–O2 batteries but is not well understood. A single unified mechanism is now described that regards previous models as limiting cases. It shows that the solubility of the intermediate LiO2 is a critical factor that dictates the mechanism, emphasizing the importance of the solvent.

881 citations


Journal ArticleDOI
30 Jan 2014-Nature
TL;DR: Comparative analysis reveals that the screened ISGs target positive-sense single-stranded RNA viruses more effectively than negative-sensesingle-strander RNA viruses.
Abstract: The type I interferon (IFN) response protects cells from viral infection by inducing hundreds of interferon-stimulated genes (ISGs), some of which encode direct antiviral effectors. Recent screening studies have begun to catalogue ISGs with antiviral activity against several RNA and DNA viruses. However, antiviral ISG specificity across multiple distinct classes of viruses remains largely unexplored. Here we used an ectopic expression assay to screen a library of more than 350 human ISGs for effects on 14 viruses representing 7 families and 11 genera. We show that 47 genes inhibit one or more viruses, and 25 genes enhance virus infectivity. Comparative analysis reveals that the screened ISGs target positive-sense single-stranded RNA viruses more effectively than negative-sense single-stranded RNA viruses. Gene clustering highlights the cytosolic DNA sensor cyclic GMP-AMP synthase (cGAS, also known as MB21D1) as a gene whose expression also broadly inhibits several RNA viruses. In vitro, lentiviral delivery of enzymatically active cGAS triggers a STING-dependent, IRF3-mediated antiviral program that functions independently of canonical IFN/STAT1 signalling. In vivo, genetic ablation of murine cGAS reveals its requirement in the antiviral response to two DNA viruses, and an unappreciated contribution to the innate control of an RNA virus. These studies uncover new paradigms for the preferential specificity of IFN-mediated antiviral pathways spanning several virus families.

765 citations


Journal ArticleDOI
TL;DR: There is a linear relationship between AMH and oocyte yield after ovarian stimulation, which is of value in predicting ovarian hyperstimulation, and the submerged part of the iceberg of follicle growth, i.e. the intrinsic, so-called 'acyclic' ovarian activity is measured.
Abstract: BACKGROUND The measurement of circulating anti-Mullerian hormone (AMH) has been applied to a wide array of clinical applications, mainly based on its ability to reflect the number of antral and pre-antral follicles present in the ovaries. AMH has been suggested to predict the ovarian response to hyperstimulation of the ovaries for IVF and the timing of menopause, and to indicate iatrogenic damage to the ovarian follicle reserve. It has also been proposed as a surrogate for antral follicle count (AFC) in the diagnosis of polycystic ovary syndrome (PCOS). METHODS This paper is a summary of presentations at a European Society of Human Reproduction and Embryology campus workshop on AMH, with literature cited until September 2013. Published peer-reviewed medical literature about AMH was searched through MEDLINE and was subjected to systematic review and critical assessment by the panel of authors. RESULTS Physiologically, recent data confirm that AMH is a follicular gatekeeper limiting follicle growth initiation, and subsequently estradiol production from small antral follicles prior to selection. AMH assays continue to evolve and technical issues remain; the absence of an international standard is a key issue. The dynamics of circulating AMH levels throughout life can be split into several distinct phases, with a peak in the early 20s before a decline to the menopause, with a strong and positive correlation with non-growing follicle recruitment. There is a more complex rise during childhood and adolescence, which is likely to be more reflective of different stages of follicle development. AMH shows limited short-term variability, but the influence of states such as prolonged oral contraceptive use need to be considered in clinical assessment. There are only very limited data on relationships between AMH and natural fertility at different stages of reproductive life, and while it has a relationship to age at menopause the marked variability in this needs further exploration. AMH may be useful in assessing the need for fertility preservation strategies and detecting post-chemotherapy or surgical damage to the ovarian reserve. Long-term follow-up of patients to ascertain fully the value of post-cancer serum AMH in predicting long-term ovarian function is required. There is a linear relationship between AMH and oocyte yield after ovarian stimulation, which is of value in predicting ovarian hyperstimulation. AMH can also identify 'poor responders', but it seems inappropriate at present to withhold IVF purely on this basis. Women with PCOS show markedly raised AMH levels, due to both the increased number of small antral follicles and intrinsic characteristics of those granulosa cells, and this may contribute to anovulation. The value of AMH in the diagnosis of PCOS remains controversial, but it may replace AFC in the future. CONCLUSIONS For the first time in female reproductive biology, it is possible to measure the submerged part of the iceberg of follicle growth, i.e. the intrinsic, so-called 'acyclic' ovarian activity. An international standard for AMH and improved assay validity are urgently needed to maximize the clinical utility of this very promising biomarker of ovarian function in a large array of clinical situations, both in childhood and adulthood.

727 citations


Journal ArticleDOI
09 Oct 2014-Nature
TL;DR: This synthesis maintains that important drivers of evolution, ones that cannot be reduced to genes, must be woven into the very fabric of evolutionary theory, and believes that the EES will shed new light on how Point Yes, urgently is shed.
Abstract: Nobel physicist talks plants with a waiter, then what? p.168 ENERGY Don't assume that renewable energies are problem-free p.168 AGEING Atul Gawande's call to action on end-of-life medical care p.167 HEALTH Lasting legacy of wartime battle against malaria p.166 Does evolutionary theory need a rethink? Researchers are divided over what processes should be considered fundamental. I n October 1881, just six months before he died, Charles Darwin published his final book. The Formation of Vegetable Mould, Through the Actions of Worms 11 sold briskly: Darwin's earlier publications had secured his reputation. He devoted an entire book to these humble creatures in part because they exemplify an interesting feedback process: earthworms are adapted to thrive in an environment that they modify through their own activities. Darwin learned about earthworms from conversations with gardeners and his own simple experiments. He had a genius for distilling penetrating insights about evolutionary processes — often after amassing years of observational and experimental data — and he drew on such disparate topics as agriculture, geology, embryol-ogy and behaviour. Evolutionary thinking ever since has followed Darwin's lead in its emphasis on evidence and in synthesizing information from other fields. A profound shift in evolutionary thinking began C harles Darwin conceived of evolution by natural selection without knowing that genes exist. Now mainstream evolutionary theory has come to focus almost exclusively on genetic inheritance and processes that change gene frequencies. Yet new data pouring out of adjacent fields are starting to undermine this narrow stance. An alternative vision of evolution is beginning to crystallize, in which the processes by which organisms grow and develop are recognized as causes of evolution. Some of us first met to discuss these advances six years ago. In the time since, as members of an interdisciplinary team, we have worked intensively to develop a broader framework, termed the extended evolutionary synthesis 1 (EES), and to flesh out its structure, assumptions and predictions. In essence, this synthesis maintains that important drivers of evolution, ones that cannot be reduced to genes, must be woven into the very fabric of evolutionary theory. We believe that the EES will shed new light on how POINT Yes, urgently Without an extended evolutionary framework, the theory neglects key processes, say Kevin Laland and colleagues.

709 citations


Journal ArticleDOI
TL;DR: It is shown that the Airy beam innately yields high contrast and resolution up to a tenfold larger FOV, and its characteristic asymmetric excitation pattern results in all fluorescence contributing positively to the contrast, enabling a step change for light-sheet microscopy.
Abstract: Light-sheet microscopy facilitates rapid, high-contrast, volumetric imaging with minimal sample exposure. However, the rapid divergence of a traditional Gaussian light sheet restricts the field of view (FOV) that provides innate subcellular resolution. We show that the Airy beam innately yields high contrast and resolution up to a tenfold larger FOV. In contrast to the Bessel beam, which also provides an increased FOV, the Airy beam's characteristic asymmetric excitation pattern results in all fluorescence contributing positively to the contrast, enabling a step change for light-sheet microscopy.

672 citations


Journal ArticleDOI
TL;DR: A review of the most important fluorinated herbicides in terms of their global use is presented in this paper, where a synthesis route is described for each compound although the synthesis presented may not actually be the industrial process.

584 citations


Journal ArticleDOI
TL;DR: The chiral stationary phase for high-performance liquid chromatography showed good chiral recognition ability towards various racemates, including Na6(CO3)(SO4)2, Na2SO4, and Na2CO3.
Abstract: Wieslaw J. Roth,†,∥ Petr Nachtigall,‡ Russell E. Morris, and Jirí̌ Čejka*,† †J. Heyrovsky ́ Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, v.v.i., Dolejsǩova 3, CZ-182 23 Prague 8, Czech Republic ‡Department of Physical and Macromolecular Chemistry, Faculty of Science, Charles University in Prague, Hlavova 2030, Prague 2, 128 00, Czech Republic EaStCHEM School of Chemistry, University of St. Andrews, St. Andrews KY16 9ST, Scotland Faculty of Chemistry, Jagiellonian University in Krakoẃ, ul. Ingardena 3,30-060 Krakoẃ, Poland

576 citations


Journal ArticleDOI
TL;DR: It is suggested that increases in absolute brain size provided the biological foundation for evolutionary increases in self-control, and implicate species differences in feeding ecology as a potential selective pressure favoring these skills.
Abstract: Cognition presents evolutionary research with one of its greatest challenges. Cognitive evolution has been explained at the proximate level by shifts in absolute and relative brain volume and at the ultimate level by differences in social and dietary complexity. However, no study has integrated the experimental and phylogenetic approach at the scale required to rigorously test these explanations. Instead, previous research has largely relied on various measures of brain size as proxies for cognitive abilities. We experimentally evaluated these major evolutionary explanations by quantitatively comparing the cognitive performance of 567 individuals representing 36 species on two problem-solving tasks measuring self-control. Phylogenetic analysis revealed that absolute brain volume best predicted performance across species and accounted for considerably more variance than brain volume controlling for body mass. This result corroborates recent advances in evolutionary neurobiology and illustrates the cognitive consequences of cortical reorganization through increases in brain volume. Within primates, dietary breadth but not social group size was a strong predictor of species differences in self-control. Our results implicate robust evolutionary relationships between dietary breadth, absolute brain volume, and self-control. These findings provide a significant first step toward quantifying the primate cognitive phenome and explaining the process of cognitive evolution.

554 citations


Journal ArticleDOI
TL;DR: Noninferiority for these regimens was not shown, which indicates that shortening treatment to 4 months was not effective in this setting, and the two moxifloxacin-containing regimens produced a more rapid initial decline in bacterial load, as compared with the control group.
Abstract: Background Early-phase and preclinical studies suggest that moxifloxacin-containing regimens could allow for effective 4-month treatment of uncomplicated, smear-positive pulmonary tuberculosis. Methods We conducted a randomized, double-blind, placebo-controlled, phase 3 trial to test the noninferiority of two moxifloxacin-containing regimens as compared with a control regimen. One group of patients received isoniazid, rifampin, pyrazinamide, and ethambutol for 8 weeks, followed by 18 weeks of isoniazid and rifampin (control group). In the second group, we replaced ethambutol with moxifloxacin for 17 weeks, followed by 9 weeks of placebo (isoniazid group), and in the third group, we replaced isoniazid with moxifloxacin for 17 weeks, followed by 9 weeks of placebo (ethambutol group). The primary end point was treatment failure or relapse within 18 months after randomization. Results Of the 1931 patients who underwent randomization, in the per-protocol analysis, a favorable outcome was reported in fewer pati...

Journal ArticleDOI
TL;DR: In this paper, the authors presented the largest and most homogeneous catalog of H ii regions and associations compiled so far, consisting of more than 7000 ionized regions, extracted from 306 galaxies observed by the CALIFA survey.
Abstract: We present the largest and most homogeneous catalog of H ii regions and associations compiled so far The catalog comprises more than 7000 ionized regions, extracted from 306 galaxies observed by the CALIFA survey We describe the procedures used to detect, select, and analyze the spectroscopic properties of these ionized regions In the current study we focus on characterizing of the radial gradient of the oxygen abundance in the ionized gas, based on the study of the deprojecteddistribution of H ii regions We found that all galaxies without clear evidence of an interaction present a common gradient in the oxygen abundance, with a characteristic slope of α_O/H = −01 dex/r_e between 03 and 2 disk effective radii (r_e), and a scatter compatible with random fluctuations around this value, when the gradient is normalized to the disk effective radius The slope is independent of morphology, the incidence of bars, absolute magnitude, or mass Only those galaxies with evidence of interactions and/or clear merging systems present a significantly shallower gradient, consistent with previous results The majority of the 94 galaxies with H ii regions detected beyond two disk effective radii present a flattening in the oxygen abundance The flattening is statistically significant We cannot provide a conclusive answer regarding the origin of this flattening However, our results indicate that its origin is most probably related to the secular evolution of galaxies Finally, we find a drop/truncation of the oxygen abundance in the inner regions for 26 of the galaxies All of them are non-interacting, mostly unbarred Sb/Sbc galaxies This feature is associated with a central star-forming ring, which suggests that both features are produced by radial gas flows induced by resonance processes Our result suggests that galaxy disks grow inside-out, with metal enrichment driven by the local star formation history and with a small variation galaxy-by-galaxy At a certain galactocentric distance, the oxygen abundance seems to be correlated well with the stellar mass density and total stellar mass of the galaxies, independently of other properties of the galaxies Other processes, such as radial mixing and inflows/outflows seem to have a limited effect on shaping of the radial distribution of oxygen abundances, although they are not ruled out

Journal ArticleDOI
TL;DR: In this paper, the authors used the off-transit variations in the star's light curve to estimate the radial-velocity variations induced by the suppression of convective blueshift and the flux blocked by starspots.
Abstract: Since the discovery of the transiting super-Earth CoRoT-7b, several investigations have yielded different results for the number and masses of planets present in the system, mainly owing to the star's high level of activity. We re-observed CoRoT-7 in 2012 January with both HARPS and CoRoT, so that we now have the benefit of simultaneous radial-velocity and photometric data. This allows us to use the off-transit variations in the star's light curve to estimate the radial-velocity variations induced by the suppression of convective blueshift and the flux blocked by starspots. To account for activity-related effects in the radial velocities which do not have a photometric signature, we also include an additional activity term in the radial-velocity model, which we treat as a Gaussian process with the same covariance properties (and hence the same frequency structure) as the light curve. Our model was incorporated into a Monte Carlo Markov Chain in order to make a precise determination of the orbits of CoRoT-7b and CoRoT-7c. We measure the masses of planets b and c to be 4.73 +/- 0.95 and 13.56 +/- 1.08 M-circle plus, respectively. The density of CoRoT-7b is (6.61 +/- 1.72)(R-p/1.58 R-circle plus)(-3) g cm(-3), which is compatible with a rocky composition. We search for evidence of an additional planet d, identified by previous authors with a period close to 9 d. We are not able to confirm the existence of a planet with this orbital period, which is close to the second harmonic of the stellar rotation at similar to 7.9 d. Using Bayesian model selection, we find that a model with two planets plus activity-induced variations is most favoured.

Journal ArticleDOI
TL;DR: In this paper, the latest developments in laser miniaturization, including those based on metals and dielectrics, are reviewed and future challenges outlined, and the emerging area of small bio-compatible or bio-derived lasers is discussed.
Abstract: The latest developments in laser miniaturization, including those based on metals and dielectrics, are reviewed and future challenges outlined. Small lasers have dimensions or modes sizes close to or smaller than the wavelength of emitted light. In recent years there has been significant progress towards reducing the size and improving the characteristics of these devices. This work has been led primarily by the innovative use of new materials and cavity designs. This Review summarizes some of the latest developments, particularly in metallic and plasmonic lasers, improvements in small dielectric lasers, and the emerging area of small bio-compatible or bio-derived lasers. We examine the different approaches employed to reduce size and how they result in significant differences in the final device, particularly between metal- and dielectric-cavity lasers. We also present potential applications for the various forms of small lasers, and indicate where further developments are required.

Journal ArticleDOI
TL;DR: In this article, the observed large-scale surface magnetic fields of low-mass stars were reconstructed through Zeeman-Doppler imaging (ZDI), and the results indicated that small and large scale fields could share the same dynamo field generation processes.
Abstract: We investigate how the observed large-scale surface magnetic fields of low-mass stars (~0.1 -- 2 Msun), reconstructed through Zeeman-Doppler imaging (ZDI), vary with age t, rotation and X-ray emission. Our sample consists of 104 magnetic maps of 73 stars, from accreting pre-main sequence to main-sequence objects (1 Myr is related to age as $t^{-0.655 \pm 0.045}$. This relation has a similar dependence to that identified by Skumanich (1972), used as the basis for gyrochronology. Likewise, our relation could be used as an age-dating method ("magnetochronology"). The trends with rotation we find for the large-scale stellar magnetism are consistent with the trends found from Zeeman broadening measurements (sensitive to large- and small-scale fields). These similarities indicate that the fields recovered from both techniques are coupled to each other, suggesting that small- and large-scale fields could share the same dynamo field generation processes. For the accreting objects, fewer statistically significant relations are found, with one being a correlation between the unsigned magnetic flux and rotation period. We attribute this to a signature of star-disc interaction, rather than being driven by the dynamo.

Journal ArticleDOI
TL;DR: The Coordinated Synoptic Investigation of NGC 2264 (CSI 2264) as discussed by the authors was a 30-day multi-wavelength photometric monitoring campaign on more than 1000 young star members using 16 telescopes.
Abstract: We present the Coordinated Synoptic Investigation of NGC 2264, a continuous 30 day multi-wavelength photometric monitoring campaign on more than 1000 young cluster members using 16 telescopes. The unprecedented combination of multi-wavelength, high-precision, high-cadence, and long-duration data opens a new window into the time domain behavior of young stellar objects. Here we provide an overview of the observations, focusing on results from Spitzer and CoRoT. The highlight of this work is detailed analysis of 162 classical T Tauri stars for which we can probe optical and mid-infrared flux variations to 1% amplitudes and sub-hour timescales. We present a morphological variability census and then use metrics of periodicity, stochasticity, and symmetry to statistically separate the light curves into seven distinct classes, which we suggest represent different physical processes and geometric effects. We provide distributions of the characteristic timescales and amplitudes and assess the fractional representation within each class. The largest category (>20%) are optical "dippers" with discrete fading events lasting ~1-5 days. The degree of correlation between the optical and infrared light curves is positive but weak; notably, the independently assigned optical and infrared morphology classes tend to be different for the same object. Assessment of flux variation behavior with respect to (circum)stellar properties reveals correlations of variability parameters with Hα emission and with effective temperature. Overall, our results point to multiple origins of young star variability, including circumstellar obscuration events, hot spots on the star and/or disk, accretion bursts, and rapid structural changes in the inner disk.

Book
07 Apr 2014
TL;DR: Magnetohydrodynamics of the Sun as discussed by the authors is a completely new up-to-date rewrite from scratch of the 1982 book Solar Magnetohydrodynamic, taking account of enormous advances in understanding since that date It describes the subtle and complex interaction between the Sun's plasma atmosphere and its magnetic field.
Abstract: Magnetohydrodynamics of the Sun is a completely new up-to-date rewrite from scratch of the 1982 book Solar Magnetohydrodynamics, taking account of enormous advances in understanding since that date It describes the subtle and complex interaction between the Sun's plasma atmosphere and its magnetic field, which is responsible for many fascinating dynamic phenomena Chapters cover the generation of the Sun's magnetic field by dynamo action, magnetoconvection and the nature of photospheric flux tubes such as sunspots, the heating of the outer atmosphere by waves or reconnection, the structure of prominences, the nature of eruptive instability and magnetic reconnection in solar flares and coronal mass ejections, and the acceleration of the solar wind by reconnection or wave-turbulence It is essential reading for graduate students and researchers in solar physics and related fields of astronomy, plasma physics and fluid dynamics Problem sets and other resources are available at wwwcambridgeorg/9780521854719

Journal ArticleDOI
TL;DR: An extensive set of gene paralogues retained from the salmonid WGD are characterized, showing that climate-linked ecophysiological factors, rather than WGD, were the primary drivers of salmonid diversification.
Abstract: Whole genome duplication (WGD) is often considered to be mechanistically associated with species diversification. Such ideas have been anecdotally attached to a WGD at the stem of the salmonid fish family, but remain untested. Here, we characterized an extensive set of gene paralogues retained from the salmonid WGD, in species covering the major lineages (subfamilies Salmoninae, Thymallinae and Coregoninae). By combining the data in calibrated relaxed molecular clock analyses, we provide the first well-constrained and direct estimate for the timing of the salmonid WGD. Our results suggest that the event occurred no later in time than 88 Ma and that 40–50 Myr passed subsequently until the subfamilies diverged. We also recovered a Thymallinae–Coregoninae sister relationship with maximal support. Comparative phylogenetic tests demonstrated that salmonid diversification patterns are closely allied in time with the continuous climatic cooling that followed the Eocene–Oligocene transition, with the highest diversification rates coinciding with recent ice ages. Further tests revealed considerably higher speciation rates in lineages that evolved anadromy—the physiological capacity to migrate between fresh and seawater—than in sister groups that retained the ancestral state of freshwater residency. Anadromy, which probably evolved in response to climatic cooling, is an established catalyst of genetic isolation, particularly during environmental perturbations (for example, glaciation cycles). We thus conclude that climate-linked ecophysiological factors, rather than WGD, were the primary drivers of salmonid diversification.

Journal ArticleDOI
TL;DR: In this article, the P2 structure has been used as positive electrodes for Na0.67Mn0.2O2 cathode materials with a capacity of 175 mA h g−1 with good capacity retention.
Abstract: Earth-abundant Na0.67[Mn1−xMgx]O2 (0 ≤ x ≤ 0.2) cathode materials with the P2 structure have been synthesized as positive electrodes for sodium-ion batteries. Na0.67MnO2 exhibits a capacity of 175 mA h g−1 with good capacity retention. A Mg content of 5% is sufficient to smooth the charge/discharge profiles without affecting the capacity, whilst further increasing the Mg content improves the cycling stability, but at the expense of a lower discharge capacity (∼150 mA h g−1 for Na0.67Mn0.8Mg0.2O2). It was observed that the cooling process during synthesis, as well as Mg content, have an influence on the structure.

Journal ArticleDOI
TL;DR: This discussion is methods‐based and focused on some algorithms that chemoinformatics researchers frequently use, particularly relevant approaches include Artificial Neural Networks, Random Forest, Support Vector Machine, k‐Nearest Neighbors and naïve Bayes classifiers.
Abstract: Machine learning algorithms are generally developed in computer science or adjacent disciplines and find their way into chemical modeling by a process of diffusion. Though particular machine learning methods are popular in chemoinformatics and quantitative structure–activity relationships (QSAR), many others exist in the technical literature. This discussion is methods-based and focused on some algorithms that chemoinformatics researchers frequently use. It makes no claim to be exhaustive. We concentrate on methods for supervised learning, predicting the unknown property values of a test set of instances, usually molecules, based on the known values for a training set. Particularly relevant approaches include Artificial Neural Networks, Random Forest, Support Vector Machine, k-Nearest Neighbors and naive Bayes classifiers. WIREs Comput Mol Sci 2014, 4:468–481. How to cite this article: WIREs Comput Mol Sci 2014, 4:468–481. doi:10.1002/wcms.1183

Journal ArticleDOI
TL;DR: In this paper, the authors explore what possibilities emerge for accounting in light of a sustainability science approach to sustainable development, and introduce sustainability science with the aim of imagining how an accounting for sustainable development might emerge.
Abstract: As the social and environmental impacts of human activity have become more evident, the role of sustainable development as an organising principle in a variety of policy contexts and over multiple scales has become central There are, at least, two implications that emerge from this observation First, morally infused problems that need to be addressed have become more intractable, requiring innovation in our modes of thinking Second, new spaces have emerged where the academy might explore how knowledge is created, validated and translated (or not) alongside policy and practice settings One outcome of these trends has been the emergence of a stream of work (sustainability science) which investigates how disciplines might develop knowledge that progresses sustainable development The aim of this paper, in line with the focus of the special issue, is to explore what possibilities emerge for accounting in light of a sustainability science approach To achieve this end the paper starts with an exploration of the frustrations expressed in the literature over the perceived lack of progress made by social and environmental accounting towards addressing sustainable development The paper then introduces sustainability science with the aim of imagining how an accounting for sustainable development might emerge The paper closes with two illustrations of how a sustainability science approach to accounting could develop


Journal ArticleDOI
18 Sep 2014-Nature
TL;DR: It is found that males were the most frequent attackers and victims; most killings involved intercommunity attacks; and attackers greatly outnumbered their victims (median 8:1 ratio).
Abstract: Observations of chimpanzees (Pan troglodytes) and bonobos (Pan paniscus) provide valuable comparative data for understanding the significance of conspecific killing. Two kinds of hypothesis have been proposed. Lethal violence is sometimes concluded to be the result of adaptive strategies, such that killers ultimately gain fitness benefits by increasing their access to resources such as food or mates. Alternatively, it could be a non-adaptive result of human impacts, such as habitat change or food provisioning. To discriminate between these hypotheses we compiled information from 18 chimpanzee communities and 4 bonobo communities studied over five decades. Our data include 152 killings (n = 58 observed, 41 inferred, and 53 suspected killings) by chimpanzees in 15 communities and one suspected killing by bonobos. We found that males were the most frequent attackers (92% of participants) and victims (73%); most killings (66%) involved intercommunity attacks; and attackers greatly outnumbered their victims (median 8:1 ratio). Variation in killing rates was unrelated to measures of human impacts. Our results are compatible with previously proposed adaptive explanations for killing by chimpanzees, whereas the human impact hypothesis is not supported.

Journal ArticleDOI
TL;DR: In this paper, a detailed two-dimensional stellar dynamical analysis of a sample of 44 cosmological hydrodynamical simulations of individual central galaxies with stellar masses of 2 × 1010 M⊙ ≲ M* ≲ 6 × 1011 M ⊙ is presented.
Abstract: We present a detailed two-dimensional stellar dynamical analysis of a sample of 44 cosmological hydrodynamical simulations of individual central galaxies with stellar masses of 2 × 1010 M⊙ ≲ M* ≲ 6 × 1011 M⊙. Kinematic maps of the stellar line-of-sight velocity, velocity dispersion and higher order Gauss-Hermite moments h3 and h4 are constructed for each central galaxy and for the most massive satellites. The amount of rotation is quantified using the λR-parameter. The velocity, velocity dispersion, h3 and h4 fields of the simulated galaxies show a diversity similar to observed kinematic maps of early-type galaxies in the ATLAS3D survey. This includes fast (regular), slow and misaligned rotation, hot spheroids with embedded cold disc components as well as galaxies with counter-rotating cores or central depressions in the velocity dispersion. We link the present-day kinematic properties to the individual cosmological formation histories of the galaxies. In general, major galaxy mergers have a significant influence on the rotation properties resulting in both a spin-down as well as a spin-up of the merger remnant. Lower mass galaxies with significant (≳18 per cent) in situ formation of stars since z ≈ 2, or with additional gas-rich major mergers - resulting in a spin-up - in their formation history, form elongated (ɛ ˜ 0.45) fast rotators (λR ˜ 0.46) with a clear anticorrelation of h3 and v/σ. An additional formation path for fast rotators includes gas-poor major mergers leading to a spin-up of the remnants (λR ˜ 0.43). This formation path does not result in anticorrelated h3 and v/σ. The formation histories of slow rotators can include late major mergers. If the merger is gas rich, the remnant typically is a less flattened slow rotator with a central dip in the velocity dispersion. If the merger is gas poor, the remnant is very elongated (ɛ ˜ 0.43) and slowly rotating (λR ˜ 0.11). The galaxies most consistent with the rare class of non-rotating round early-type galaxies grow by gas-poor minor mergers alone. In general, more massive galaxies have less in situ star formation since z ˜ 2, rotate slower and have older stellar populations. We discuss general implications for the formation of fast and slowly rotating galaxies as well as the weaknesses and strengths of the underlying models.

Journal ArticleDOI
18 Apr 2014-Science
TL;DR: To probe the proposed px ± ipy topological superconducting state of Sr2RuO4, an apparatus capable of applying both compressive and tensile strains of up to 0.23% is constructed and has potential applicability to a wide range of problems in solid-state physics.
Abstract: A sensitive probe of unconventional order is its response to a symmetry-breaking field. To probe the proposed px ± ipy topological superconducting state of Sr2RuO4, we have constructed an apparatus capable of applying both compressive and tensile strains of up to 0.23%. Strains applied along 〈 100 〉 crystallographic directions yield a strong, strain-symmetric increase in the superconducting transition temperature Tc. 〈 110 〉 strains give a much weaker, mostly antisymmetric response. As well as advancing the understanding of the superconductivity of Sr2RuO4, our technique has potential applicability to a wide range of problems in solid-state physics.

Journal ArticleDOI
TL;DR: Investigation of a material with a different structure from that of NaMnO2 polymorphs, with a high capacity, that exhibits stable, reproducible, and reversible Na intercalation is observed in Na-ion batteries for grid storage.
Abstract: There is much interest in Na-ion batteries for grid storage because of the lower projected cost compared with Li-ion. Identifying Earth-abundant, low-cost, and safe materials that can function as intercalation cathodes in Na-ion batteries is an important challenge facing the field. Here we investigate such a material, β-NaMnO2, with a different structure from that of NaMnO2 polymorphs and other compounds studied extensively in the past. It exhibits a high capacity (of ca. 190 mA h g–1 at a rate of C/20), along with a good rate capability (142 mA h g–1 at a rate of 2C) and a good capacity retention (100 mA h g–1after 100 Na extraction/insertion cycles at a rate of 2C). Powder XRD, HRTEM, and 23Na NMR studies revealed that this compound exhibits a complex structure consisting of intergrown regions of α-NaMnO2 and β-NaMnO2 domains. The collapse of the long-range structure at low Na content is expected to compromise the reversibility of the Na extraction and insertion processes occurring upon charge and disch...

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TL;DR: The need to engage the community in design, implementation, and uptake of research is emphasised, to increase international cooperation between drug developers and health-care providers adopting new regimens.
Abstract: About 1·3 million people died of tuberculosis in 2012, despite availability of effective drug treatment. Barriers to improvements in outcomes include long treatment duration (resulting in poor patient adherence and loss of patients to follow-up), complex regimens that involve expensive and toxic drugs, toxic effects when given with antiretroviral therapy, and multidrug resistance. After 50 years of no antituberculosis drug development, a promising pipeline is emerging through the repurposing of old drugs, re-engineering of existing antibacterial compounds, and discovery of new compounds. A range of novel antituberculosis drugs are in preclinical development, several phase 2 and 3 trials are underway, and use of adjunct therapies is being explored for drug-sensitive and drug-resistant tuberculosis. Historical advances include approval of two new drugs, delamanid and bedaquiline. Combinations of new and existing drugs are being assessed to shorten the duration of therapy and to treat multidrug-resistant tuberculosis. There has also been progress in development of new antituberculosis drugs that are active against dormant or persister populations of Mycobacterium tuberculosis. In this Review, we discuss recent advances in antituberculosis drug discovery and development, clinical trial designs, laboratory methods, and adjunct host-directed therapies, and we provide an update of phase 3 trials of various fluoroquinolones (RIFAQUIN, NIRT, OFLOTUB, and REMoxTB). We also emphasise the need to engage the community in design, implementation, and uptake of research, to increase international cooperation between drug developers and health-care providers adopting new regimens.

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TL;DR: In this paper, the authors used a grant from the National Natural Science Foundation of China (NSFC no. 70962001) to support the work of the second author.
Abstract: This work has been supported by a grant (FL110100199) from the Australian Research Council awarded to the second author, a grant from the Research Foundation Flanders awarded to the fifth author, and a grant from the National Natural Science Foundation of China (NSFC no. 70962001) awarded to the sixth author.

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TL;DR: In this article, the spin and angle-resolved photo-emission spectroscopy of spin-polarized bulk states in the centrosymmetric transition-metal dichalcogenide WSe has been used to show how spin splittings up to ∼ 0.5 eV result, with a spin texture that is strongly modulated in both real and momentum space.
Abstract: The coupling between spin, valley and layer degrees of freedom in transition-metal dichalcogenides is shown to give rise to spin-polarized electron states, providing opportunities to create and manipulate spin and valley polarizations in bulk solids. Methods to generate spin-polarized electronic states in non-magnetic solids are strongly desired to enable all-electrical manipulation of electron spins for new quantum devices1. This is generally accepted to require breaking global structural inversion symmetry1,2,3,4,5. In contrast, here we report the observation from spin- and angle-resolved photoemission spectroscopy of spin-polarized bulk states in the centrosymmetric transition-metal dichalcogenide WSe2. Mediated by a lack of inversion symmetry in constituent structural units of the bulk crystal where the electronic states are localized6, we show how spin splittings up to ∼0.5 eV result, with a spin texture that is strongly modulated in both real and momentum space. Through this, our study provides direct experimental evidence for a putative locking of the spin with the layer and valley pseudospins in transition-metal dichalcogenides7,8, of key importance for using these compounds in proposed valleytronic devices.

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TL;DR: It is found that it is possible to greatly reduce error rates by considering the results of all three methods when identifying outlier loci, and the relative ranking between the methods is impacted by the consideration of polygenic selection.
Abstract: The recent availability of next-generation sequencing (NGS) has made possible the use of dense genetic markers to identify regions of the genome that may be under the influence of selection. Several statistical methods have been developed recently for this purpose. Here, we present the results of an individual-based simulation study investigating the power and error rate of popular or recent genome scan methods: linear regression, Bayescan, BayEnv and LFMM. Contrary to previous studies, we focus on complex, hierarchical population structure and on polygenic selection. Additionally, we use a false discovery rate (FDR)-based framework, which provides an unified testing framework across frequentist and Bayesian methods. Finally, we investigate the influence of population allele frequencies versus individual genotype data specification for LFMM and the linear regression. The relative ranking between the methods is impacted by the consideration of polygenic selection, compared to a monogenic scenario. For strongly hierarchical scenarios with confounding effects between demography and environmental variables, the power of the methods can be very low. Except for one scenario, Bayescan exhibited moderate power and error rate. BayEnv performance was good under nonhierarchical scenarios, while LFMM provided the best compromise between power and error rate across scenarios. We found that it is possible to greatly reduce error rates by considering the results of all three methods when identifying outlier loci.