bluuebunny/crossref_metadata_2025 huggingface dataset:
Pulse width modulation technique for a three‐to‐five phase matrix converter with reduced commutations
Authors: Sayed Mahmoud A. , Iqbal Atif
Published: November 2015

Variable‐speed multiphase drive systems have become an increasingly important topics compared with conventional three‐phase one due to their distinct advantages. This study presents a new pulse width modulation (PWM) technique for controlling the three‐to‐five phase matrix converter to reduce the commutation number of the power switches and the total harmonic distortion, simultaneously. The proposed PWM technique provides full output voltage and frequency control in addition to unity input power factor by changing only five switch states during the control period. Moreover, it prevents direct switching or commutation between the maximum and minimum input voltages to reduce the switches voltage stress. Moreover, the proposed PWM technique provides output voltage ratio equal to 78.86% of the input voltage. The effectiveness of the proposed control scheme has been verified theoretically by using PSIM software and experimentally by using a laboratory prototype.
Thermokinetics of heterogeneous droplet nucleation on conically textured substrates
Authors: Singha Sanat K. , Das Prasanta K. , Maiti Biswajit
Published: November 2015

Within the framework of the classical theory of heterogeneous nucleation, a thermokinetic model is developed for line-tension-associated droplet nucleation on conical textures considering growth or shrinkage of the formed cluster due to both interfacial and peripheral monomer exchange and by considering different geometric configurations. Along with the principle of free energy extremization, Katz kinetic approach has been employed to study the effect of substrate conicity and wettability on the thermokinetics of heterogeneous water droplet nucleation. Not only the peripheral tension is found to have a considerable effect on the free energy barrier but also the substrate hydrophobicity and hydrophilicity are observed to switch over their roles between conical crest and trough for different growth rates of the droplet. Besides, the rate of nucleation increases and further promotes nucleation for negative peripheral tension as it diminishes the free energy barrier appreciably. Moreover, nucleation inhibition can be achievable for positive peripheral tension due to the enhancement of the free energy barrier. Analyzing all possible geometric configurations, the hydrophilic narrower conical cavity is found to be the most preferred nucleation site. These findings suggest a physical insight into the context of surface engineering for the promotion or the suppression of nucleation on real or engineered substrates.
Designing a stochastic genetic switch by coupling chaos and bistability
Authors: Zhao Xiang , Ouyang Qi , Wang Hongli
Published: November 2015

In stem cell differentiation, a pluripotent stem cell becomes progressively specialized and generates specific cell types through a series of epigenetic processes. How cells can precisely determine their fate in a fluctuating environment is a currently unsolved problem. In this paper, we suggest an abstract gene regulatory network to describe mathematically the differentiation phenomenon featuring stochasticity, divergent cell fates, and robustness. The network consists of three functional motifs: an upstream chaotic motif, a buffering motif of incoherent feed forward loop capable of generating a pulse, and a downstream motif which is bistable. The dynamic behavior is typically a transient chaos with fractal basin boundaries. The trajectories take transiently chaotic journeys before divergently settling down to the bistable states. The ratio of the probability that the high state is achieved to the probability that the low state is reached can maintain a constant in a population of cells with varied molecular fluctuations. The ratio can be turned up or down when proper parameters are adjusted. The model suggests a possible mechanism for the robustness against fluctuations that is prominently featured in pluripotent cell differentiations and developmental phenomena.
Energy landscape of LeuT from molecular simulations
Authors: Gur Mert , Zomot Elia , Cheng Mary Hongying , Bahar Ivet
Published: November 2015

The bacterial sodium-coupled leucine transporter (LeuT) has been broadly used as a structural model for understanding the structure-dynamics-function of mammalian neurotransmitter transporters as well as other solute carriers that share the same fold (LeuT fold), as the first member of the family crystallographically resolved in multiple states: outward-facing open, outward-facing occluded, and inward-facing open. Yet, a complete picture of the energy landscape of (sub)states visited along the LeuT transport cycle has been elusive. In an attempt to visualize the conformational spectrum of LeuT, we performed extensive simulations of LeuT dimer dynamics in the presence of substrate (Ala or Leu) and co-transported Na+ ions, in explicit membrane and water. We used both conventional molecular dynamics (MD) simulations (with Anton supercomputing machine) and a recently introduced method, collective MD, that takes advantage of collective modes of motions predicted by the anisotropic network model. Free energy landscapes constructed based on ∼40 μs trajectories reveal multiple substates occluded to the extracellular (EC) and/or intracellular (IC) media, varying in the levels of exposure of LeuT to EC or IC vestibules. The IC-facing transmembrane (TM) helical segment TM1a shows an opening, albeit to a smaller extent and in a slightly different direction than that observed in the inward-facing open crystal structure. The study provides insights into the spectrum of conformational substates and paths accessible to LeuT and highlights the differences between Ala- and Leu-bound substates.
Cold and ultracold dynamics of the barrierless D+ + H2 reaction: Quantum reactive calculations for ∼R−4 long range interaction potentials
Authors: Lara Manuel , Jambrina P. G. , Aoiz F. J. , Launay J.-M.
Published: November 2015

Quantum reactive and elastic cross sections and rate coefficients have been calculated for D+ + H2 (v = 0, j = 0) collisions in the energy range from 10−8 K (deep ultracold regime), where only one partial wave is open, to 150 K (Langevin regime) where many of them contribute. In systems involving ions, the ∼R−4 behavior extends the interaction up to extremely long distances, requiring a special treatment. To this purpose, we have used a modified version of the hyperspherical quantum reactive scattering method, which allows the propagations up to distances of 105 a0 needed to converge the elastic cross sections. Interpolation procedures are also proposed which may reduce the cost of exact dynamical calculations at such low energies. Calculations have been carried out on the PES by Velilla et al. [J. Chem. Phys. 129, 084307 (2008)] which accurately reproduces the long range interactions. Results on its prequel, the PES by Aguado et al. [J. Chem. Phys. 112, 1240 (2000)], are also shown in order to emphasize the significance of the inclusion of the long range interactions. The calculated reaction rate coefficient changes less than one order of magnitude in a collision energy range of ten orders of magnitude, and it is found in very good agreement with the available experimental data in the region where they exist (10-100 K). State-to-state reaction probabilities are also provided which show that for each partial wave, the distribution of HD final states remains essentially constant below 1 K.
Device level optimization of poly(vinylidene fluoride-trifluoroethylene)–zinc oxide polymer nanocomposite thin films for ferroelectric applications
Authors: C K Subash , Valiyaneerilakkal Uvais , Singh Kulwant , Varghese Soney
Published: November 2015

Polymer nanocomposite was prepared using poly(vinylidene fluoride-trifluoroethylene) and zinc oxide (ZnO) nanopowder, which are ferroelectric in nature. Nanocomposite was prepared in various concentrations(0.2, 0.4, 0.8, and 1 wt. %) using probe ultra-sonication, followed by spin coating and annealing at 120 °C for 2 h to improve the formation of β-phase. Metal-ferroelectric-metal capacitor was fabricated using this optimized thin film as a ferroelectric layer. Device level optimization was carried out by polarization-electric field (P-E) hysteresis studies of this film, which shows polarization enhancement of composite. Various characterization techniques like atomic force microscopy, Fourier transform infra-red spectroscopy (FT-IR), Differential scanning calorimetry, and X-ray diffraction were used to study the β-phase formation of nancomposite. The capacitance–voltage (C-V) and current-voltage (I-V) characteristics were studied through varying frequency and temperature. C-V measurements show an increase of 79% in the capacitance of polymer nanocomposite, which can be used for the fabrication of ferroelectric devices.
Omnidirectional polarization-insensitive tunable absorption in graphene metamaterial of nanodisk structure
Authors: Ning Renxia , Bao Jie , Jiao Zheng , Xu Yuan
Published: November 2015

Tunable absorption based on graphene metamaterial with nanodisk structure at near-infrared frequency was investigated using the finite difference time domain method. The absorption of the nanodisk structure which consisting of Au-MgF2-graphene-Au-polyimide (from bottom to top) can be tuned by the chemical potential of graphene at certain diameter of nanodisk. The permittivity of graphene is discussed with different chemical potential to obtain tunable absorption. It is shown that the increased value of the chemical potential of graphene can lead to blue-shifted of the absorption peaks and the values decreased. Moreover, dual-band and triple-band absorption can be achieved for resonance frequencies at normal incidence. Compared with diameter of nanodisks, the multilayer structure shows multi-band absorber, and an omnidirectional absorption at 195.25 THz is insensitive to TE/TM polarization. This omnidirectional polarization insensitive absorption may be applied by optical communications such as optical absorber, near infrared stealth, and filter.
Polarization properties of light scattered off solutions of chiral molecules in non-forward direction
Authors: Vidal Xavier , Fernandez-Corbaton Ivan , Barbara Alex F. , Molina-Terriza Gabriel
Published: November 2015

Measuring the optical activity from an ensemble of chiral molecules is a common tool to know their stereo-structure. These measurements are done in the same propagation direction of the probe beam of light, because that is the direction where most signal is emitted. We provide experimental and theoretical evidence that, even though other interesting information may be gathered when collecting light emitted in other directions, for most molecules, the phenomenon of optical activity is only present in the forward scattering direction. The fundamental reason behind this is that forward scattered light preserves the circular polarization states due to the cylindrical symmetry of the system, an essential requirement for optical activity. An important exemption happens in dual molecules, i.e., molecules which present the same response to electric and magnetic fields. We present a series of experiments measuring the optical activity and the scattering of chiral solutions in the forward and perpendicular directions. We experimentally show that these molecules present optical activity and preservation of circular polarization in the forward direction, while the polarization pattern in non-forward directions is much more complex and, in particular, does not preserve the circular polarization. Finally, we show that when probing the particle with different wavelengths, the scattering in non-forward directions presents some interesting structural features which are hidden in the forward measurements.
Comparison of the Marcus and Pekar partitions in the context of non-equilibrium, polarizable-continuum solvation models
Authors: You Zhi-Qiang , Mewes Jan-Michael , Dreuw Andreas , Herbert John M.
Published: November 2015

The Marcus and Pekar partitions are common, alternative models to describe the non-equilibrium dielectric polarization response that accompanies instantaneous perturbation of a solute embedded in a dielectric continuum. Examples of such a perturbation include vertical electronic excitation and vertical ionization of a solution-phase molecule. Here, we provide a general derivation of the accompanying polarization response, for a quantum-mechanical solute described within the framework of a polarizable continuum model (PCM) of electrostatic solvation. Although the non-equilibrium free energy is formally equivalent within the two partitions, albeit partitioned differently into “fast” versus “slow” polarization contributions, discretization of the PCM integral equations fails to preserve certain symmetries contained in these equations (except in the case of the conductor-like models or when the solute cavity is spherical), leading to alternative, non-equivalent matrix equations. Unlike the total equilibrium solvation energy, however, which can differ dramatically between different formulations, we demonstrate that the equivalence of the Marcus and Pekar partitions for the non-equilibrium solvation correction is preserved to high accuracy. Differences in vertical excitation and ionization energies are <0.2 eV (and often <0.01 eV), even for systems specifically selected to afford a large polarization response. Numerical results therefore support the interchangeability of the Marcus and Pekar partitions, but also caution against relying too much on the fast PCM charges for interpretive value, as these charges differ greatly between the two partitions, especially in polar solvents.
Approaches to management of complaints and notifications about health practitioners in Australia
Authors: Satchell Claudette S. , Walton Merrilyn , Kelly Patrick J. , Chiarella Elizabeth M. , Pierce Suzanne M. , Nagy Marie T. , Bennett Belinda , Carney Terry
Published: November 2015

In 2005, the Australian Productivity Commission made a recommendation that a national health registration regimen and a consolidated national accreditation regimen be established. On 1 July 2010, the National Registration and Accreditation Scheme (NRAS) for health practitioners came into effect and the Australian Health Practitioner Regulation Agency (AHPRA) became the single national oversight agency for health professional regulation. It is governed by the Health Practitioner Regulation National Law Act (the National Law). While all states and territories joined NRAS for registration and accreditation, NSW did not join the scheme for the handling of complaints, but retained its existing co-regulatory complaint-handling system. All other states and territories joined the national notification (complaints) scheme prescribed in the National Law. Because the introduction of NRAS brings with it new processes and governance around the management of complaints that apply to all regulated health professionals in all states and territories except NSW, where complaints management remains largely unchanged, there is a need for comparative analysis of these differing national and NSW approaches to the management of complaints/notifications about health professionals, not only to allow transparency for consumers, but also to assess consistency of decision making around complaints/notifications across jurisdictions. This paper describes the similarities and differences for complaints/notifications handling between the NRAS and NSW schemes and briefly discusses subsequent and potential changes in other jurisdictions.
Role of palaeoecology in describing the ecological character of wetlands
Authors: Finlayson C. Max , Clarke Stewart J. , Davidson Nick C. , Gell Peter
Published: November 2015

While it is acknowledged that changes in the condition of a wetland can be detected through contemporary monitoring programs, this paper explores the extent to which palaeoecological approaches can be used in concert with contemporary techniques to understand benchmark conditions, rates and direction of change. This is done within the context of the Ramsar Convention on Wetlands that addresses the conservation of internationally important wetlands and the wise use of all wetlands. Over time the Convention has adopted a considerable body of guidance on detecting, reporting and responding to change in ecological character. In recognition that there remain gaps in available guidance on ecological character the Convention has requested further advice on the determination of appropriate reference conditions for assessing change and establishing the range of natural variability of wetlands. As palaeoecological approaches provide a ready means of considering the trajectories of change, and the nature and drivers of change over time, they can assist in qualifying established ecological descriptions. They can also help understand the timing and nature of any departure from normal conditions, and provide early warnings of future change, especially when integrated with contemporary monitoring and modelling.
Constructions and language change
Authors: Nesset Tore , Kuznetsova Julia
Published: November 2015

This article reports on a corpus study of ongoing language change in Russian, whereby genitive-governing verbs like bojat’sja “fear” combine with objects in the accusative in addition to the traditionally normative genitive. While the use of the accusative is still not very frequent in Contemporary Standard Russian, we demonstrate that it is increasing and that a number of factors such as individuation (animacy), grammatical voice, frequency and verb semantics (intensionality and directionality) promote the use of the accusative. Our analysis is couched in Construction Grammar, and we show that the shift from genitive to accusative objects in Russian provides empirical support for Construction Grammar as a theory applicable to language change.
Adjectives, communities, and taxonomies of evaluative meaning
Authors: Millar Neil , Hunston Susan
Published: November 2015

From a corpus consisting of free text comments submitted to the website RateMyProfessors.com, adjectives describing people have been identified and clustered using Principal Components Analysis. This follows the Meaning Extraction method used by Chung & Pennebaker (2007). The outcome is a set of seven factors, each of which is interpretable as representing a dimension of meaning along which individual professors have been evaluated. These dimensions are in turn discussed using Martin & White’s (2005) parameters of Judgement and Appreciation, and Coffin’s (2002) concept of evaluative voices. It is argued that contributors to RateMyProfessors.com have available three distinct voices: ‘novice intellectual’, ‘consumer’, and ‘subordinate’. The paper demonstrates how a bottom-up, statistical technique may be used to provide the initial data for identifying evaluative parameters. It raises the possibility that such parameters may be specific to individual discourse communities. It therefore offers a complementary and problematizing alternative to top-down, researcher-driven taxonomies of evaluative meaning.
Good vibrations: Global processing can increase the pleasantness of touch
Authors: Mirams Laura , Poliakoff Ellen , Zandstra Elizabeth H. , Hoeksma Marco , Thomas Anna , El-Deredy Wael
Published: November 2015

Visual–tactile carry-over effects of global/local processing (attention to the whole, versus the details) have been reported under active touch conditions. We investigated whether carry-over effects of global/local processing also occur for passive touch and whether global/local processing has differential effects on affective and discriminative aspects of touch. Participants completed two tactile tasks involving pleasantness rating and discrimination of a set of tactile vibrations before and after completing a version of the Navon task that encouraged a focus on the global ( n = 30), local ( n = 30), or both ( n = 30) features of a series of visual stimuli. In line with previous research suggesting a link between global processing and positive emotion, global processing increased pleasantness ratings of high-frequency (but not low-frequency) tactile vibrations. Local processing did not improve the ability to discriminate between vibrations of different frequencies, however. There was some evidence of a tactile–visual carry-over effect; prior local processing of tactile vibrations reduced global precedence during the Navon task in the control group. We have shown carry-over effects of global versus local processing on passive touch perception. These findings provide further evidence suggesting that a common perceptual mechanism determines processing level across modalities and show for the first time that prior global processing affects the pleasantness of touch.
Aristotle: A Very Short Introduction
Authors: Barnes Jonathan
Published: November 2015

Aristotle: A Very Short Introduction argues that Aristotle’s influence on the intellectual history of the West is second to none. His various doctrines and beliefs were purveyed as received truths, and his ideas, or their reflections, influenced philosophers and scientists, historians and theologians, poets and playwrights. The structure as well as the content of Aristotle’s thought was influential — even those determined to reject Aristotelian views found themselves doing so in Aristotelian language. This VSI examines Aristotle’s scientific researches, his discoveries in logic and his metaphysical theories, his work in psychology, ethics and politics, and his ideas about art and poetry, placing his teachings in their historical context.
International Law: A Very Short Introduction
Authors: Lowe Vaughan
Published: November 2015

Recently, interest in international law has increased greatly, largely because of its central place in discussions such as the Iraq War, the World Trade Organization, the Kyoto Convention, the situations in Palestine and Darfur, and the plights of refugees and illegal immigrants around the world. International Law: A Very Short Introduction explains what international law is, its role in international society, and how it operates. It examines what international law can and cannot do and what it is and isn’t doing to make the world a better place. It uses terrorism, environmental change, poverty, and international violence to demonstrate international law theories and practice, and how the principles can be used for international cooperation.
Coronary pressure and flow relationships in humans: phasic analysis of normal and pathological vessels and the implications for stenosis assessment: a report from the Iberian–Dutch–English (IDEAL) collaborators
Authors: Nijjer Sukhjinder S. , de Waard Guus A. , Sen Sayan , van de Hoef Tim P. , Petraco Ricardo , Echavarría-Pinto Mauro , van Lavieren Martijn A. , Meuwissen Martijn , Danad Ibrahim , Knaapen Paul , Escaned Javier , Piek Jan J. , Davies Justin E. , van Royen Niels
Published: November 2015

Background

Our understanding of human coronary physiological behaviour is derived from animal models. We sought to describe physiological behaviour across a large collection of invasive pressure and flow velocity measurements, to provide a better understanding of the relationships between these physiological parameters and to evaluate the rationale for resting stenosis assessment.

Methods and results

Five hundred and sixty-seven simultaneous intracoronary pressure and flow velocity assessments from 301 patients were analysed for coronary flow velocity, trans-stenotic pressure gradient (TG), and microvascular resistance (MVR). Measurements were made during baseline and hyperaemic conditions. The whole cardiac cycle and the diastolic wave-free period were assessed. Stenoses were assessed according to fractional flow reserve (FFR) and quantitative coronary angiography DS%. With progressive worsening of stenoses, from unobstructed angiographic normal vessels to those with FFR ≤ 0.50, hyperaemic flow falls significantly from 45 to 19 cm/s, Ptrend < 0.001 in a curvilinear pattern. Resting flow was unaffected by stenosis severity and was consistent across all strata of stenosis ( Ptrend > 0.05 for all). Trans-stenotic pressure gradient rose with stenosis severity for both rest and hyperaemic measures ( Ptrend < 0.001 for both). Microvascular resistance declines with stenosis severity under resting conditions ( Ptrend < 0.001), but was unchanged at hyperaemia (2.3 ± 1.1 mmHg/cm/s; Ptrend = 0.19).

Conclusions

With progressive stenosis severity, TG rises. However, while hyperaemic flow falls significantly, resting coronary flow is maintained by compensatory reduction of MVR, demonstrating coronary auto-regulation. These data support the translation of coronary physiological concepts derived from animals to patients with coronary artery disease and furthermore, suggest that resting pressure indices can be used to detect the haemodynamic significance of coronary artery stenoses.
Projecting marine fish production and catch potential in Bangladesh in the 21st century under long-term environmental change and management scenarios
Authors: Fernandes Jose A. , Kay Susan , Hossain Mostafa A. R. , Ahmed Munir , Cheung William W. L. , Lazar Attila N. , Barange Manuel
Published: November 2015

The fisheries sector is crucial to the Bangladeshi economy and wellbeing, accounting for 4.4% of national gross domestic product and 22.8% of agriculture sector production, and supplying ca. 60% of the national animal protein intake. Fish is vital to the 16 million Bangladeshis living near the coast, a number that has doubled since the 1980s. Here, we develop and apply tools to project the long-term productive capacity of Bangladesh marine fisheries under climate and fisheries management scenarios, based on downscaling a global climate model, using associated river flow and nutrient loading estimates, projecting high-resolution changes in physical and biochemical ocean properties, and eventually projecting fish production and catch potential under different fishing mortality targets. We place particular interest on Hilsa shad (Tenualosa ilisha), which accounts for ca. 11% of total catches, and Bombay duck (Harpadon nehereus), a low price fish that is the second highest catch in Bangladesh and is highly consumed by low-income communities. It is concluded that the impacts of climate change, under greenhouse emissions scenario A1B, are likely to reduce the potential fish production in the Bangladesh exclusive economic zone by <10%. However, these impacts are larger for the two target species. Under sustainable management practices, we expect Hilsa shad catches to show a minor decline in potential catch by 2030 but a significant (25%) decline by 2060. However, if overexploitation is allowed, catches are projected to fall much further, by almost 95% by 2060, compared with the Business as Usual scenario for the start of the 21st century. For Bombay duck, potential catches by 2060 under sustainable scenarios will produce a decline of <20% compared with current catches. The results demonstrate that management can mitigate or exacerbate the effects of climate change on ecosystem productivity.
How to Have Difficult Conversations
Authors: de Oliveira Justine Strand
Published: November 2015

Drawing on the experiences of hundreds of public health and primary care clinicians from across the United States, this book explains why population health is receiving so much attention from policy makers in states and federal agencies, the practical steps that clinicians and public health professionals can take to work together to meet the needs of their community, signs that you are on the right track (or not) and how to sustain successes to the benefit of patients, community members, and the health care and public health teams that care for them.
Pitching Your Project
Authors: de Oliveira Justine Strand
Published: November 2015

Drawing on the experiences of hundreds of public health and primary care clinicians from across the United States, this book explains why population health is receiving so much attention from policy makers in states and federal agencies, the practical steps that clinicians and public health professionals can take to work together to meet the needs of their community, signs that you are on the right track (or not) and how to sustain successes to the benefit of patients, community members, and the health care and public health teams that care for them.
Community Health Assessments: Past, Present, and Future
Authors: Barnett Kevin , Rosenbaum Sara
Published: November 2015

Drawing on the experiences of hundreds of public health and primary care clinicians from across the United States, this book explains why population health is receiving so much attention from policy makers in states and federal agencies, the practical steps that clinicians and public health professionals can take to work together to meet the needs of their community, signs that you are on the right track (or not) and how to sustain successes to the benefit of patients, community members, and the health care and public health teams that care for them.
San Diego, California, Promotes Healthy Weight to Improve Community Health
Authors: Serpas Shaila , Khaokham Christina , Hillidge Sharon , Watson Virginia
Published: November 2015

Drawing on the experiences of hundreds of public health and primary care clinicians from across the United States, this book explains why population health is receiving so much attention from policy makers in states and federal agencies, the practical steps that clinicians and public health professionals can take to work together to meet the needs of their community, signs that you are on the right track (or not) and how to sustain successes to the benefit of patients, community members, and the health care and public health teams that care for them.
Parkinson’s disease
Authors: Lees A. J.
Published: November 2015

The following landmark discoveries in our understanding of Parkinson’s disease are considered in this chapter: the first full medical description of the malady; consistent severe loss of pigmented cells in the substantia nigra; severe depletion of striatal dopamine; the use of high doses of racemic dopa to improve the motor symptoms; a superior animal model for the study of potential new treatments; functional lesioning and deep brain stimulation to relieve symptoms; capability of fetal dopamine cells to reinnervate the striatum and improve handicap; a compensatory phase before the emergence of motor symptoms and nigral cell loss beginning about five years prior to the onset of presenting symptoms; a large autosomal dominant family with Parkinsonism found to carry a genetic mutation of alpha synuclein; and discovery of Lewy bodies in surviving grafted fetal neuronal cells many years after successful implantation.
Mitochondrial diseases
Authors: Gorman Gráinne S. , Chinnery Patrick F.
Published: November 2015

This chapter critiques ten seminal papers that epitomize the advent and evolution of mitochondrial medicine from the latter half of the last century up until today. These important bodies of work span the pre-molecular and molecular eras, from when diagnostic yield was based on meticulous clinical and biochemical characterization of patients, up until now, with targeted next-generation sequencing revolutionizing our diagnostic approach. The first clinical description of a mitochondrial disorder is reviewed and the subsequent landmark papers that define current clinical and molecular understanding of human diseases caused by inherited disorders of mitochondrial dysfunction are chronicled. The chapter also charts the shift in emphasis from diagnosis to the development of treatments and novel approaches for disease prevention.
Multiple sclerosis
Authors: Coles Alasdair , Compston Alastair
Published: November 2015

The papers in this chapter illustrate the picture that has emerged of multiple sclerosis as an inflammatory disorder of the central nervous system, caused by a complex interplay of multiple genetic susceptibility alleles and unknown environmental triggers. Multiple sclerosis is a disease in which there is first demyelination of nerves, followed by axonal degeneration. Demyelination is caused by inflammation, as shown by the synthesis of immunoglobulins within the CNS, and magnetic resonance imaging has shown that only the minority of inflammatory lesions cause symptoms. All of these discoveries were made in the twentieth century, which ended with the first demonstration that a treatment—interferon-beta—could influence the natural history of the disease.
Ghost in the time series: no planet for Alpha Cen B
Authors: Rajpaul V. , Aigrain S. , Roberts S.
Published: November 2015

We re-analyse the publicly available radial velocity (RV) measurements for Alpha Cen B, a star hosting an Earth-mass planet candidate, Alpha Cen Bb, with 3.24 d orbital period. We demonstrate that the 3.24 d signal observed in the Alpha Cen B data almost certainly arises from the window function (time sampling) of the original data. We show that when stellar activity signals are removed from the RV variations, other significant peaks in the power spectrum of the window function are coincidentally suppressed, leaving behind a spurious yet apparently significant ‘ghost’ of a signal that was present in the window function's power spectrum ab initio. Even when fitting synthetic data with time sampling identical to the original data, but devoid of any genuine periodicities close to that of the planet candidate, the original model used to infer the presence of Alpha Cen Bb leads to identical conclusions: viz., the 3σ detection of a half-a-metre-per-second signal with 3.236 d period. Our analysis underscores the difficulty of detecting weak planetary signals in RV data, and the importance of understanding in detail how every component of an RV data set, including its time sampling, influences final statistical inference.
A phylogenetically diverse class of “blind” type 1 opsins
Authors: Becker Erin A. , Yao Andrew I. , Seitzer Phillip M. , Kind Tobias , Wang Ting , Eigenheer Rich , Shao Katie S. Y. , Yarov-Yarovoy Vladimir , Facciotti Marc T.
Published: November 2015

Opsins are photosensitive proteins catalyzing light-dependent processes across the tree of life. For both microbial (type 1) and metazoan (type 2) opsins, photosensing depends upon covalent interaction between a retinal chromophore and a conserved lysine residue. Despite recent discoveries of potential opsin homologs lacking this residue, phylogenetic dispersal and functional significance of these abnormal sequences have not yet been investigated. We report discovery of a large group of putatively non-retinal binding opsins, present in a number of fungal and microbial genomes and comprising nearly 30% of opsins in theHalobacteriacea, a model clade for opsin photobiology. Based on phylogenetic analyses, structural modeling, genomic context and biochemistry, we propose that these abnormal opsin homologs represent a novel family of sensory opsins which may be involved in taxis response to one or more non-light stimuli. This finding challenges current understanding of microbial opsins as a light-specific sensory family, and provides a potential analogy with the highly diverse signaling capabilities of the eukaryotic G-protein coupled receptors (GPCRs), of which metazoan type 2 opsins are a light-specific sub-clade.
Influence of polychromaticity on particle structure determination in small-angle X-ray scattering
Authors: Wang Wenjia , Shtykova Eleonora V. , Volkov Vladimir V. , Chang Guangcai , Zhang Lianhui , Dong Yuhui , Liu Peng
Published: November 2015

Pink beams are now widely used for small-angle X-ray scattering (SAXS) data collection owing to their high intensity. However, the wavelength spread of a pink beam is a factor of 100 higher than that of a monochromatic beam, thus causing the experimental data to be smeared. To reveal the influence of polychromaticity on shape reconstruction, four geometric bodies (sphere, cube, helix and long cylinder) were used for SAXS data analysis. The results reveal that the influence of polychromaticity on the process of shape reconstruction is significantly more dependent on the geometry of the body than on its size. Scattering objects with smoothed scattering curves can tolerate a higher wavelength spread than those with tortuous curves. It is further demonstrated that the structural parameters calculated from the smeared data sets have little deviation from the ideal ones, which indicates the possibility of using a light source with a greater wavelength spread than a conventional pink beam for special time-resolved SAXS experiments. Finally, it is concluded that SAXS data collected in pink-beam mode can be used directly for structural calculations and model reconstructions without a desmearing procedure.
Algorithms for determining the phase of RHEED oscillations
Authors: Mitura Zbigniew , Dudarev Sergei L.
Published: November 2015

Oscillations of reflection high-energy electron diffraction (RHEED) intensities are computed using dynamical diffraction theory. The phase of the oscillations is determined using two different approaches. In the first, direct, approach, the phase is determined by identifying the time needed to reach the second oscillation minimum. In the second approach, the phase is found using harmonic analysis. The two approaches are tested by applying them to oscillations simulated using dynamical diffraction theory. The phase of RHEED oscillations observed experimentally is also analysed. Experimental data on the variation of the phase as a function of the glancing angle of incidence, derived using the direct method, are compared with the values computed using both the direct and harmonic methods. For incident-beam azimuths corresponding to low-symmetry directions, both approaches produce similar results.
DEBUSSY 2.0: the new release of a Debye user system for nanocrystalline and/or disordered materials
Authors: Cervellino Antonio , Frison Ruggero , Bertolotti Federica , Guagliardi Antonietta
Published: November 2015

The new release ofDEBUSSYis introduced, a free open-source package devoted to the application of the Debye function analysis of powder diffraction data from nanocrystalline, defective and/or nonperiodic materials. The general strategy of the suite remains unchanged, following a two-step approach managed by theCLAUDEandDEBUSSYprograms, respectively. The first step essentially consists in generating a database where structural, size and shape information on a nanocrystal population is stored; the second step consists in the calculation, through the Debye scattering equation, of the total diffraction pattern using the previously generated database and a set of model parameters provided by the user and then optimized by the program. The novelties lie in the computational, modelling and graphical levels, and several new programs and features have been added. Among these are a new general comprehensive input file format (.ddb) for the database generation, the automatic management of the space-group symmetry and .cif file, new nanocrystal shapes, size-dependent site occupancy factors and thermal parameters for each atomic species, new lattice expansion functions, and a newly developed algorithm for calculating the standard errors of the optimized parameters. TheCLAUDEsuite also includes a program for calculation of the pair distribution function. Last but not least, a graphical user interface, which makes it easier to edit input files, execute the programs of the suite in a chain-like way, and plot the results in an automatic or custom manner, is provided.
Solution scattering from colloidal curved plates: barrel tiles, scrolls and spherical patches
Authors: Constantin Doru
Published: November 2015

Analytical or semi-analytical expressions are provided for the small-angle scattering of colloidal objects that can be described as curved plates. These models could help to characterize a variety of inorganic or biological systems.
The same once again please: a pedagogical introduction to normalizers
Authors: Nespolo Massimo
Published: November 2015

Normalizers of space groups are extensively used in the solution of diverse tasks in structural crystallography. Yet, they are often considered an `esoteric' topic, seldom introduced in the education curriculum of a crystallographer. This paper presents a pedagogical introduction with special emphasis on their role in the equivalent description of crystal structures.
The benefits of one-dimensional detectors for high-pressure powder X-ray diffraction
Authors: Fisch Martin , Lanza Arianna , Macchi Piero , Casati Nicola
Published: November 2015

High-pressure powder X-ray diffraction is a fundamental technique for investigating structural responses to externally applied force. Synchrotron sources and two-dimensional detectors are required. In contrast to this conventional setup, high-resolution beamlines equipped with one-dimensional detectors could offer much better resolved peaks but cannot deliver accurate structure factors because they only sample a small portion of the Debye rings, which are usually inhomogeneous and spotty because of the small amount of sample. In this study, a simple method to overcome this problem is presented and successfully applied to solving the structure of an L-serine polymorph from powder data. A comparison of the obtained high-resolution high-pressure data with conventional data shows that this technique, providing up to ten times better angular resolution, can be of advantage for indexing, for lattice parameter refinement, and even for structure refinement and solution in special cases.
Structures and packing of ferrocenylmethyl methacrylate and ferrocene-1,1′-diylbis(methylene) dimethacrylate
Authors: McAdam C. John , Moratti Stephen C. , Simpson Jim
Published: November 2015

Electroactive metallocene polymers are of interest due to the possibility that they offer a muscle-like response, and in gel systems very large volume changes are possible. The ferrocenyl moiety exhibits physical and electrochemical stability of the neutral and oxidized forms and could be a candidate for use as the redox-active group in these materials. The title compounds, [Fe(C5H5)(C10H11O2)], (I), and [Fe(C10H11O2)2], (II), comprise a typical ferrocene core with coplanar and approximately eclipsed cyclopentadienyl (Cp) rings. In (I), there is a single methyl methacrylate substituent, with the other Cp ring unsubstituted. In (II), a methyl methacrylate substituent on each Cp ring completes the structure. In both compounds, there is an s-transgeometry of the vinyl and carbonyl components of the methacrylate group. Inversion dimers formed through C—H...O contacts dominate the crystal packing of both molecules. Weak C—H...π(ring) contacts and, in the case of (I), an unusual C—H...π(alkene) contact further stabilize the structures.
Crystal structure of (4-methoxyphenyl)[(4-methoxyphenyl)phosphonato]dioxidophosphate(1−) 2-amino-6-benzyl-3-ethoxycarbonyl-4,5,6,7-tetrahydrothieno[2,3-c]pyridin-6-ium
Authors: Mague Joel T. , Mohamed Shaaban K. , Akkurt Mehmet , Younes Sabry H. H. , Ahmed Essam K. , Albayati Mustafa R.
Published: November 2015

The asymmetric unit of the title molecular salt, C17H21N2O2S+·C14H15O7P2−, comprises two cations and two anions. Each cation features an intramolecular N—H...O hydrogen bond, which closes anS(6) ring; in each case the hydropyridine ring adopts a half-chair conformation. In the anions, the dihedral angles between the aromatic rings are 64.1 (2) and 54.9 (2)°. In each case, the diphosphate groups are close to eclipsed [C—P...P—C pseudo-torsion angles = 11.6 (2) and −19.3 (2)°]. One of the methoxy groups in each anion is disordered over two orientations in a 0.539 (18):0.461 (18) ratio in one anion and 0.82 (2):0.18 (2) in the other. In the crystal, O—H...O and N—H...O hydrogen bonds link the components into [100] chains. Numerous C—H...O interactions cross-link the chains into a three-dimensional network.
Ca4As3– a new binary calcium arsenide
Authors: Hoffmann Andrea V. , Hlukhyy Viktor , Fässler Thomas F.
Published: November 2015

The crystal structure of the binary compound tetracalcium triarsenide, Ca4As3, was investigated by single-crystal X-ray diffraction. Ca4As3crystallizes in the Ba4P3structure type and is thus a homologue of isotypic Sr4As3. The unit cell contains 32 Ca2+cations, 16 As3−isolated anions and four centrosymmetric [As2]4–dumbbells. The As atoms in each of the dumbbells are connected by a single bond, thus this calcium arsenide is a Zintl phase.
Crystal structure of 3-O-benzyl-4(R)-C-(1-benzyl-1H-1,2,3-triazol-4-yl)-1,2-O-isopropylidene-α-D-erythrofuranose
Authors: Semjonovs Nikita , Rjabovs Vitalijs , Stepanovs Dmitrijs , Turks Maris
Published: November 2015

The title compound, C23H25N3O4, {systematic name: 1-benzyl-4-[(3aR,5R,6R,6aR)-6-benzyloxy-2,2-dimethyltetrahydrofuro[2,3-d][1,3]dioxol-5-yl]-1H-1,2,3-triazole}, consists of a substituted 2,2-dimethyltetrahydrofuro[2,3-d][1,3]dioxole. The furanose ring adopts an envelope conformation close toC3-exo, where the C atom substituted by the benzyloxy group is the flap. The fused dioxolane ring also adopts an envelope conformation, with the methylene C atom as the flap. In the crystal, molecules are linked by weak C—H...O hydrogen bonds, forming zigzag chains along [010].
Crystal structure of 2-oxo-N′-phenyl-2H-chromene-3-carbohydrazide
Authors: Mague Joel T. , Mohamed Shaaban K. , Akkurt Mehmet , Younes Sabry H. H. , Albayati Mustafa R.
Published: November 2015

In the title compound, C16H12N2O3, the 2H-chromene moiety is essentially planar, with an r.m.s. deviation of the nine constituent atoms from the mean plane of 0.0093 Å, and makes a dihedral angle of 76.84 (3)° with the pendant phenyl ring. An intramolecular N—H...O hydrogen bond helps to determine the conformation of the side chain. In the crystal, N—H...O and N—H...N hydrogen bonds link the molecules, forming [100] chains.
Crystal structure of cyproconazole
Authors: Kang Gihaeng , Kim Jineun , Kwon Eunjin , Kim Tae Ho
Published: November 2015

The title compound [systematic name: 2-(4-chlorophenyl)-3-cyclopropyl-1-(1H-1,2,4-triazol-1-yl)butan-2-ol], C15H18ClN3O, is a conazole fungicide. The asymmetric unit comprises two enantiomeric pairs (moleculesAandB) in which the dihedral angles between the chlorophenyl and triazole rings are 46.54 (9) (moleculeA) and 67.03 (8)° (moleculeB). In the crystal, C—H...O, O—H...N and C—H...Cl hydrogen bonds and weak C—H...π interactions [3.473 (2) Å] link adjacent molecules, forming columns along theaaxis.
The COBRA fixed-wing georeferenced imagery dataset
Authors: Saeedi Sajad , Thibault Carl , Trentini Michael , Li Howard
Published: November 2015

Purpose

– The purpose of this paper is to present a localization and mapping data set acquired by a fixed-wing unmanned aerial vehicle (UAV). The data set was collected for educational and research purposes: to save time in dealing with hardware and to compare the results with a benchmark data set. The data were collected in standard Robot Operating System (ROS) format. The environment, fixed-wing, and sensor configuration are explained in detail. GPS coordinates of the fixed-wing are also available as ground truth. The data set is available for download (www.ece.unb.ca/COBRA/open_source.htm).

Design/methodology/approach

– The data were collected in standard ROS format. The environment, fixed-wing, and sensor configuration are explained in detail.

Findings

– The data set can be used for target localization and mapping. The data were collected to assist algorithm developments and help researchers to compare their results. Robotic data sets are specifically important when they are related to unmanned systems such as fixed-wing aircraft.

Originality/value

– The Robotics Data Set Repository (RADISH) by A. Howard and N. Roy hosts 41 well-known data sets with different sensors; however, there is no fixed-wing data set in RADISH. This work presents two data sets collected by a fixed-wing aircraft using ROS standards. The data sets can be used for target localization and SLAM.