bluuebunny/crossref_metadata_2025 huggingface dataset:
Improved methods for daily streamflow estimates at ungauged sites
Authors: Shu Chang , Ouarda Taha B. M. J.
Published: January 2012

In this paper, improved flow duration curve (FDC) and area ratio (AR) based methods are developed to obtain better daily streamflow estimation at ungauged sites. A regression based logarithmic interpolation method which makes no assumption on the distribution or shape of a FDC is introduced in this paper to estimate regional FDCs. The estimated FDC is combined with a spatial interpolation algorithm to obtain daily streamflow estimates. Multiple source sites based AR methods, especially the geographical distance weighted AR (GWAR) method, are introduced in an effort to maximize the use of regional information and improve the standard AR method (SAR). Performances of the proposed approaches are evaluated using a jackknife procedure. The application to 109 stations in the province of Quebec, Canada indicates that the FDC based methods outperform AR based methods in all the summary statistics including Nash, root mean squared error (RMSE), and Bias. The number of sites that show better performances using the FDC based approaches is also significantly larger than the number of sites showing better performances using AR based methods. Using geographical distance weighted multiple sources sites based approaches can improve the performance at the majority of the catchments comparing with using the single source site based approaches.
Vocal Tract Representation in the Recognition of Cerebral Palsied Speech
Authors: Rudzicz Frank , Hirst Graeme , van Lieshout Pascal
Published: January 2012

Purpose

In this study, the authors explored articulatory information as a means of improving the recognition of dysarthric speech by machine.

Method

Data were derived chiefly from the TORGO database of dysarthric articulation (Rudzicz, Namasivayam, & Wolff, 2011) in which motions of various points in the vocal tract are measured during speech. In the 1st experiment, the authors provided a baseline model indicating a relatively low performance with traditional automatic speech recognition (ASR) using only acoustic data from dysarthric individuals. In the 2nd experiment, the authors used various measures of entropy (statistical disorder) to determine whether characteristics of dysarthric articulation can reduce uncertainty in features of dysarthric acoustics. These findings led to the 3rd experiment, in which recorded dysarthric articulation was directly encoded into the speech recognition process.

Results

The authors found that 18.3% of the statistical disorder in the acoustics of speakers with dysarthria can be removed if articulatory parameters are known. Using articulatory models reduces phoneme recognition errors relatively by up to 6% for speakers with dysarthria in speaker-dependent systems.

Conclusions

Articulatory knowledge is useful in reducing rates of error in ASR for speakers with dysarthria and in reducing statistical uncertainty of their acoustic signals. These findings may help to guide clinical decisions related to the use of ASR in the future.
Invited Article: Refractive index matched scanning of dense granular materials
Authors: Dijksman Joshua A. , Rietz Frank , Lőrincz Kinga A. , van Hecke Martin , Losert Wolfgang
Published: January 2012

We review an experimental method that allows to probe the time-dependent structure of fully three-dimensional densely packed granular materials and suspensions by means of particle recognition. The method relies on submersing a granular medium in a refractive index matched fluid. This makes the resulting suspension transparent. The granular medium is then visualized by exciting, layer by layer, the fluorescent dye in the fluid phase. We collect references and unreported experimental know-how to provide a solid background for future development of the technique, both for new and experienced users.
Large anisotropic remnant magnetization tunability in (011)-La2/3Sr1/3MnO3/0.7Pb(Mg2/3Nb1/3)O3-0.3PbTiO3 multiferroic epitaxial heterostructures
Authors: Yang Yuanjun , Meng Yang Meng , Luo Z. L. , Huang Haoliang , Wang Haibo , Bao J. , Hu Chuansheng , Pan Guoqiang , Yao Yiping , Liu Yukuai , Li X. G. , Zhang Sen , Zhao Y. G. , Gao C.
Published: January 2012

A large anisotropic remnant magnetization tunability was observed in multiferroic (011)-La2/3Sr1/3MnO3/0.7Pb(Mg2/3Nb1/3)O3-0.3PbTiO3 (LSMO/PMN-0.3PT) epitaxial heterostructures. The remnant magnetization along [100] direction was suppressed by an electric field applied to the substrate while the remnant magnetization along [011¯] was enhanced. The tunabilities of the remnant magnetization along the [100] and [011¯] directions are about −17.9% and +157% under electric field of +7.27 kV/cm, respectively. This large anisotropic remnant magnetization tunability may find potential applications in the electrically written and magnetically read memories.
Perturbation analysis of acoustic wave scattering at rough solid-solid interfaces
Authors: Sun Huarui , Pipe Kevin P.
Published: January 2012

We apply a boundary perturbation approach to model the scattering of acoustic waves at rough solid-solid interfaces. This method incorporates mode conversion and allows straightforward separation of specular and diffuse components, the relative fractions of which play an important role in determining thermal boundary resistance and the performance of acoustic phonon devices. The effect of acoustic impedance mismatch on the distribution of scattered waves is investigated, as well as the coupling to interface modes.
Analytical properties of horizontal visibility graphs in the Feigenbaum scenario
Authors: Luque Bartolo , Lacasa Lucas , Ballesteros Fernando J. , Robledo Alberto
Published: January 2012

Time series are proficiently converted into graphs via the horizontal visibility (HV) algorithm, which prompts interest in its capability for capturing the nature of different classes of series in a network context. We have recently shown [B. Luque et al., PLoS ONE 6, 9 (2011)] that dynamical systems can be studied from a novel perspective via the use of this method. Specifically, the period-doubling and band-splitting attractor cascades that characterize unimodal maps transform into families of graphs that turn out to be independent of map nonlinearity or other particulars. Here, we provide an in depth description of the HV treatment of the Feigenbaum scenario, together with analytical derivations that relate to the degree distributions, mean distances, clustering coefficients, etc., associated to the bifurcation cascades and their accumulation points. We describe how the resultant families of graphs can be framed into a renormalization group scheme in which fixed-point graphs reveal their scaling properties. These fixed points are then re-derived from an entropy optimization process defined for the graph sets, confirming a suggested connection between renormalization group and entropy optimization. Finally, we provide analytical and numerical results for the graph entropy and show that it emulates the Lyapunov exponent of the map independently of its sign.
Molecular vibrations of methane molecules in the structure I clathrate hydrate from ab initio molecular dynamics simulation
Authors: Hiratsuka Masaki , Ohmura Ryo , Sum Amadeu K. , Yasuoka Kenji
Published: January 2012

Vibrational frequencies of guest molecules in clathrate hydrates reflect the molecular environment and dynamical behavior of molecules. A detailed understanding of the mechanism for the vibrational frequency changes of the guest molecules in the clathrate hydrate cages is still incomplete. In this study, molecular vibrations of methane molecules in a structure I clathrate hydrate are calculated from ab initio molecular dynamics simulation. The vibrational spectra of methane are computed by Fourier transform of autocorrelation functions, which reveal distinct separation of each vibrational mode. Calculated symmetric and asymmetric stretching vibrational frequencies of methane molecules are lower in the large cages than in the small cages (8 and 16 cm−1 for symmetric and asymmetric stretching, respectively). These changes are closely linked with the C–H bond length. The vibrational frequencies for the bending and rocking vibrational modes nearly overlap in each of the cages.
Propagation of nonlinear coherent structures in a collisional magnetoplasma with nonthermal electrons and finite ion temperature
Authors: Masood W. , Rizvi H. , Imtiaz N.
Published: January 2012

Nonlinear electrostatic waves in dissipative magnetized electron-ion (e-i) plasmas are investigated employing the two fluid model. In this regard, Zakharov Kuznetsov Burgers (ZKB) equation is derived using the small amplitude perturbation expansion method. It is observed that the nonthermal electron population, obliqueness, ion thermal effects, and kinematic viscosity significantly alter the structure of obliquely propagating nonlinear ion acoustic shock waves in dissipative e-i magnetoplasmas. It is observed that the system can admit both compressive and rarefactive shocks. The condition for the formation of both types of shocks is also given. The present study may be useful to understand the nonlinear propagation characteristics of electrostatic shock structures in space environments where the nonthermal electrons have been observed by various satellite missions such as Voyager and Freja.
X-ray detection capability of a BaCl2 single crystal scintillator
Authors: Koshimizu Masanori , Onodera Kazuya , Nishikido Fumihiko , Haruki Rie , Shibuya Kengo , Kishimoto Shunji , Asai Keisuke
Published: January 2012

The x-ray detection capability of a scintillation detector equipped with a BaCl2 single crystal was evaluated. The scintillation decay kinetics can be expressed by a sum of two exponential decay components. The fast and slow components have lifetimes of 1.5 and 85 ns, respectively. The total light output is 5% that of YAP:Ce. A subnanosecond timing resolution was obtained. The detection efficiency of a 67.41 keV x-ray is 87% for a detector equipped with a BaCl2 crystal 6-mm thick. Thus, excellent timing resolution and high detection efficiency can be simultaneously achieved. Additionally, luminescence decay characteristics under vacuum ultraviolet excitation have been investigated. Radiative decay of self-trapped excitons is thought to be responsible for the fast scintillation component.
Mid-infrared spectroscopy of molecular ions in helium nanodroplets
Authors: Zhang Xiaohang , Brauer Nils B. , Berden Giel , Rijs Anouk M. , Drabbels Marcel
Published: January 2012

High resolution IR spectra of aniline, styrene, and 1,1-diphenylethylene cations embedded in superfluid helium nanodroplets have been recorded in the 300–1700 cm−1 range using a free-electron laser as radiation source. Comparison of the spectra with available gas phase data reveals that the helium environment induces no significant matrix shift nor leads to an observable line broadening of the resonances. In addition, the IR spectra have provided new and improved vibrational transition frequencies for the cations investigated, as well as for neutral aniline and styrene. Indications have been found that the ions desolvate from the droplets after excitation by a non-evaporative process in which they are ejected from the helium droplets. The kinetic energy of the ejected ions is found to be ion specific and to depend only weakly on the excitation energy.
Experimental studies of complex hydride YMn2H6 on formation kinetics and x-ray absorption fine structure analyses
Authors: Matsuo Motoaki , Matsumura Daiju , Nishihata Yasuo , Li Guanqiao , Hiyama Nao , Semboshi Satoshi , Orimo Shin-ichi
Published: January 2012

Formation kinetics of a complex hydride YMn2H6 with [MnH6]5− complex anion from a metal hydride YMn2H4.5 was investigated in the temperature range between 373 K and 448 K under 25 MPa H2. The time dependent of the YMn2H6 formation fraction suggested that the formation kinetics are controlled by random nucleation and growth with the activation energy of 113 kJ/mol H2. Local structure of YMn2H6 synthesized was also studied by x-ray absorption fine structure analysis. Mn–H covalent bonding nature in [MnH6]5− complex anion was successfully detected and the Mn–H distance was determined to be 1.67 ± 0.05 Å.
Modeling the hydration of mono-atomic anions from the gas phase to the bulk phase: The case of the halide ions F−, Cl−, and Br−
Authors: Trumm Michael , Martínez Yansel Omar Guerrero , Réal Florent , Masella Michel , Vallet Valérie , Schimmelpfennig Bernd
Published: January 2012

In this work, we investigate the hydration of the halide ions fluoride, chloride, and bromide using classical molecular dynamics simulations at the 10 ns scale and based on a polarizable force-field approach, which treats explicitly the cooperative bond character of strong hydrogen bond networks. We have carried out a thorough analysis of the ab initio data at the MP2 or CCSD(T) level concerning anion/water clusters in gas phase to adjust the force-field parameters. In particular, we consider the anion static polarizabilities computed in gas phase using large atomic basis sets including additional diffuse functions. The information extracted from trajectories in solution shows well structured first hydration shells formed of 6.7, 7.0, and 7.6 water molecules at about 2.78 Å, 3.15 Å, and 3.36 Å for fluoride, chloride, and bromide, respectively. These results are in excellent agreement with the latest neutron- and x-ray diffraction studies. In addition, our model reproduces several other properties of halide ions in solution, such as diffusion coefficients, description of hydration processes, and exchange reactions. Moreover, it is also able to reproduce the electrostatic properties of the anions in solution (in terms of anion dipole moment) as reported by recent ab initio quantum simulations. All the results show the ability of the proposed model in predicting data, as well as the need of accounting explicitly for the cooperative character of strong hydrogen bonds to reproduce ab initio potential energy surfaces in a mean square sense and to build up a reliable force field.
Nano-hole array structure with improved surface plasmon energy matching characteristics
Authors: Najiminaini Mohamadreza , Vasefi Fartash , Kaminska Bozena , Carson Jeffrey J. L.
Published: January 2012

We present a nano-hole array structure in an opaque gold film that contains a cavity beneath each nano-hole. The cavity contributes to surface plasmon energy matching between the top and bottom surfaces of the gold and within the nano-hole structures. Based on bulk surface plasmon resonance (SPR) sensing experiments, the SP-matched structure had 2.8-fold higher differential transmission, 2-fold higher sensitivity, and a 7-fold higher ratio of extraordinary optical transmission at resonance to the nearby minimum compared to a conventional NHA. The results suggest that the structure with cavities has potential to improve performance of bulk SPR sensing applications.
Direct patterning of functional interfaces in oxide heterostructures
Authors: Banerjee N. , Huijben M. , Koster G. , Rijnders G.
Published: January 2012

We report on the direct patterning of high-quality structures incorporating the LaAlO3-SrTiO3 interface by an epitaxial-liftoff technique avoiding any reactive ion beam etching. Detailed studies of temperature dependent magnetotransport properties were performed on the patterned heterostructures with variable thickness of the LaAlO3 layer and compared to their unstructured thin film analogues. The results demonstrate the conservation of the high-quality interface properties in the patterned structures enabling future studies of low-dimensional confinement on high mobility interface conductivity as well as interface magnetism.
Extracting accurate capacitance voltage curves from impedance spectroscopy
Authors: Guenther Kay-Michael , Witte Hartmut , Krost Alois , Kontermann Stefan , Schade Wolfgang
Published: January 2012

We propose a method to obtain accurate capacitance-voltage (C-V) curves in the presence of multiple space charges. This method uses impedance spectroscopy to evaluate individual space charges separately. The advantage is that the knowledge of the exact equivalent circuit is not essentially needed. The comparison with other methods to calculate the doping concentration NA shows that our method is unaffected by series resistances and agrees best with the correct value of NA. The evaluation of the impedance spectra leads to a more thorough understanding of the respective Mott-Schottky plots.
Metal-insulator transition sustained by Cr-doping in V2O3 nanocrystals
Authors: Ishiwata Yoichi , Shiraishi Tatsuya , Ito Naoki , Suehiro Satoshi , Kida Tetsuya , Ishii Hirofumi , Tezuka Yasuhisa , Inagaki Yuji , Kawae Tatsuya , Oosato Hirotaka , Watanabe Eiichiro , Tsuya Daiju , Nantoh Masashi , Ishibashi Koji
Published: January 2012

We have obtained monodisperse (V1−xCrx)2O3 nanocrystals with crystal sizes of 21.0 ± 4.1 nm using organic-phase synthesis. The (V1−xCrx)2O3 nanocrystals clearly show the transition from a corundum structured paramagnetic metal to a monoclinic structured antiferromagnetic insulator in contrast to non-doped V2O3 nanocrystals, in which the disappearance of the metal-insulator transition has been observed. We have found that Cr doping works effectively in narrowing the a1g band, which tends to be broadened by nanocrystallization. This result suggests that chemical doping is useful for control of material phase transitions at the nanoscale.
Ceasing of voltage switching amongst graphitic shells in multiwalled carbon nanotubes: A route toward stability
Authors: Kulshrestha Neha , Misra Abhishek , Bajpai Reeti , Roy Soumyendu , Misra D. S.
Published: January 2012

Weakly interacting graphitic shells of different resistivities within multiwalled carbon nanotubes (MWNTs) cause instability in current and thus limit their reliability for electronic device applications. We here demonstrate voltage switching amongst graphitic shells of MWNTs by applying current sweeps with observed switching time in the range of 100–400 ms. We further demonstrate ceasing of this switching behaviour by local metal deposition on the MWNTs. After metal deposition, the graphitic shells behave like resistive wires connected altogether. This concept of metal deposition benefits in the higher conductivity and stable currents for MWNTs and proves their strong candidature as interconnecting wires.
A note on the nucleation with multiple steps: Parallel and series nucleation
Authors: Iwamatsu Masao
Published: January 2012

Parallel and series nucleation are the basic elements of the complex nucleation process when two saddle points exist on the free-energy landscape. It is pointed out that the nucleation rates follow formulas similar to those of parallel and series connection of resistors or conductors in an electric circuit. Necessary formulas to calculate individual nucleation rates at the saddle points and the total nucleation rate are summarized, and the extension to the more complex nucleation process is suggested.
Cholera toxin activates nonconventional adjuvant pathways that induce protective CD8 T-cell responses after epicutaneous vaccination
Authors: Olvera-Gomez Irlanda , Hamilton Sara E. , Xiao Zhengguo , Guimaraes Carla P. , Ploegh Hidde L. , Hogquist Kristin A. , Wang Liangchun , Jameson Stephen C.
Published: January 2012

The ability to induce humoral and cellular immunity via antigen delivery through the unbroken skin (epicutaneous immunization, EPI) has immediate relevance for vaccine development. However, it is unclear which adjuvants induce protective memory CD8 T-cell responses by this route, and the molecular and cellular requirements for priming through intact skin are not defined. We report that cholera toxin (CT) is superior to other adjuvants in its ability to prime memory CD8 T cells that control bacterial and viral challenges. Epicutaneous immunization with CT does not require engagement of classic toll-like receptor (TLR) and inflammasome pathways and, surprisingly, is independent of skin langerin-expressing cells (including Langerhans cells). However, CT adjuvanticity required type-I IFN sensitivity, participation of a Batf3-dependent dendritic cell (DC) population and engagement of CT with suitable gangliosides. Chemoenzymatic generation of CT–antigen fusion proteins led to efficient priming of the CD8 T-cell responses, paving the way for development of this immunization strategy as a therapeutic option.
Functional characteristics of developmental dyslexia in left-hemispheric posterior brain regions predate reading onset
Authors: Raschle Nora Maria , Zuk Jennifer , Gaab Nadine
Published: January 2012

Individuals with developmental dyslexia (DD) show a disruption in posterior left-hemispheric neural networks during phonological processing. Additionally, compensatory mechanisms in children and adults with DD have been located within frontal brain areas. However, it remains unclear when and how differences in posterior left-hemispheric networks manifest and whether compensatory mechanisms have already started to develop in the prereading brain. Here we investigate functional networks during phonological processing in 36 prereading children with a familial risk for DD (
n
= 18, average age = 66.50 mo) compared with age and IQ-matched controls (
n
= 18; average age = 65.61 mo). Functional neuroimaging results reveal reduced activation in prereading children with a family-history of DD (FHD
+
), compared with those without (FHD
−
), in bilateral occipitotemporal and left temporoparietal brain regions. This finding corresponds to previously identified hypoactivations in left hemispheric posterior brain regions for school-aged children and adults with a diagnosis of DD. Furthermore, left occipitotemporal and temporoparietal brain activity correlates positively with prereading skills in both groups. Our results suggest that differences in neural correlates of phonological processing in individuals with DD are not a result of reading failure, but are present before literacy acquisition starts. Additionally, no hyperactivation in frontal brain regions was observed, suggesting that compensatory mechanisms for reading failure are not yet present. Future longitudinal studies are needed to determine whether the identified differences may serve as neural premarkers for the early identification of children at risk for DD.
Partitioning sexual selection into its mating success and fertilization success components
Authors: Pischedda Alison , Rice William R.
Published: January 2012

Postcopulatory sexual selection due to sperm competition and/or cryptic female choice has been documented in a diversity of taxonomic groups and is considered a pivotal component of sexual selection. Despite this apparent importance, the relative contribution of postcopulatory fertilization success to overall sexual selection has not yet been measured in any species. Here, we used a laboratory-adapted population of the promiscuous fruit fly
Drosophila melanogaster
to partition the variance in male reproductive success into mating success (a major component of precopulatory sexual selection) and fertilization success (a major component of postcopulatory sexual selection). We found that fertilization success contributed nearly as strongly as mating success to a male's net performance in sexual selection, but that most of this postcopulatory component was attributable to variation in male mating order (the tendency to be the last male to mate a female). After adjusting for mating order, only ≈2% of the residual variation in male reproductive success was attributable to differential fertilization success. We found no correlation between male mating success and fertilization success in this system. Unlike natural populations of
Drosophila
, our laboratory population is adapted to a semelparous lifecycle, so our findings will be most applicable to other promiscuous species with strong sperm precedence and one short breeding period per year or lifetime. In these species, fertilization success may have as much influence on male reproductive success as mating success, but the timing of mating (mating order) may be the predominant factor contributing to variation in fertilization success.
Target-of-rapamycin complex 1 (Torc1) signaling modulates cilia size and function through protein synthesis regulation
Authors: Yuan Shiaulou , Li Jade , Diener Dennis R. , Choma Michael A. , Rosenbaum Joel L. , Sun Zhaoxia
Published: January 2012

The cilium serves as a cellular antenna by coordinating upstream environmental cues with numerous downstream signaling processes that are indispensable for the function of the cell. This role is supported by the revelation that defects of the cilium underlie an emerging class of human disorders, termed “ciliopathies.” Although mounting interest in the cilium has demonstrated the essential role that the organelle plays in vertebrate development, homeostasis, and disease pathogenesis, the mechanisms regulating cilia morphology and function remain unclear. Here, we show that the target-of-rapamycin (TOR) growth pathway modulates cilia size and function during zebrafish development. Knockdown oftuberous sclerosis complex 1a(tsc1a), which encodes an upstream inhibitor of TOR complex 1 (Torc1), increases cilia length. In contrast, treatment of embryos with rapamycin, an inhibitor of Torc1, shortens cilia length. Overexpression ofribosomal protein S6 kinase 1(S6k1), which encodes a downstream substrate of Torc1, lengthens cilia. Furthermore, we provide evidence that TOR-mediated cilia assembly is evolutionarily conserved and that protein synthesis is essential for this regulation. Finally, we demonstrate that TOR signaling and cilia length are pivotal for a variety of downstream ciliary functions, such as cilia motility, fluid flow generation, and the establishment of left-right body asymmetry. Our findings reveal a unique role for the TOR pathway in regulating cilia size through protein synthesis and suggest that appropriate and defined lengths are necessary for proper function of the cilium.
Strand swapping regulates the iron-sulfur cluster in the diabetes drug target mitoNEET
Authors: Baxter Elizabeth Leigh , Jennings Patricia A. , Onuchic José N.
Published: January 2012

MitoNEET is a recently identified diabetes drug target that coordinates a transferable 2Fe-2S cluster, and additionally contains an unusual strand swap. In this manuscript, we use a dual basin structure-based model to predict and characterize the folding and functionality of strand swapping in mitoNEET. We demonstrate that a strand unswapped conformation is kinetically accessible and that multiple levels of control are employed to regulate the conformational dynamics of the system. Environmental factors such as temperature can shift route preference toward the unswapped pathway. Additionally we see that a region recently identified as contributing to frustration in folding acts as a regulatory hinge loop that modulates conformational balance. Interestingly, strand unswapping transfers strain specifically to cluster-coordinating residues, opening the cluster-coordinating pocket. Strengthening contacts within the cluster-coordinating pocket opens a new pathway between the swapped and unswapped conformation that utilizes cracking to bypass the unfolded basin. These results suggest that local control within distinct regions affect motions important in regulating mitoNEET’s 2Fe-2S clusters.
Functional profiling of neurons through cellular neuropharmacology
Authors: Teichert Russell W. , Smith Nathan J. , Raghuraman Shrinivasan , Yoshikami Doju , Light Alan R. , Olivera Baldomero M.
Published: January 2012

We describe a functional profiling strategy to identify and characterize subtypes of neurons present in a peripheral ganglion, which should be extendable to neurons in the CNS. In this study, dissociated dorsal-root ganglion neurons from mice were exposed to various pharmacological agents (challenge compounds), while at the same time the individual responses of >100 neurons were simultaneously monitored by calcium imaging. Each challenge compound elicited responses in only a subset of dorsal-root ganglion neurons. Two general types of challenge compounds were used: agonists of receptors (ionotropic and metabotropic) that alter cytoplasmic calcium concentration (receptor–agonist challenges) and compounds that affect voltage-gated ion channels (membrane–potential challenges). Notably, among the latter are K-channel antagonists, which elicited unexpectedly diverse types of calcium responses in different cells (i.e., phenotypes). We used various challenge compounds to identify several putative neuronal subtypes on the basis of their shared and/or divergent functional, phenotypic profiles. Our results indicate that multiple receptor–agonist and membrane–potential challenges may be applied to a neuronal population to identify, characterize, and discriminate among neuronal subtypes. This experimental approach can uncover constellations of plasma membrane macromolecules that are functionally coupled to confer a specific phenotypic profile on each neuronal subtype. This experimental platform has the potential to bridge a gap between systems and molecular neuroscience with a cellular-focused neuropharmacology, ultimately leading to the identification and functional characterization of all neuronal subtypes at a given locus in the nervous system.
Gene therapy rescues photoreceptor blindness in dogs and paves the way for treating human X-linked retinitis pigmentosa
Authors: Beltran William A. , Cideciyan Artur V. , Lewin Alfred S. , Iwabe Simone , Khanna Hemant , Sumaroka Alexander , Chiodo Vince A. , Fajardo Diego S. , Román Alejandro J. , Deng Wen-Tao , Swider Malgorzata , Alemán Tomas S. , Boye Sanford L. , Genini Sem , Swaroop Anand , Hauswirth William W. , Jacobson Samuel G. , Aguirre Gustavo D.
Published: January 2012

Hereditary retinal blindness is caused by mutations in genes expressed in photoreceptors or retinal pigment epithelium. Gene therapy in mouse and dog models of a primary retinal pigment epithelium disease has already been translated to human clinical trials with encouraging results. Treatment for common primary photoreceptor blindness, however, has not yet moved from proof of concept to the clinic. We evaluated gene augmentation therapy in two blinding canine photoreceptor diseases that model the common X-linked form of retinitis pigmentosa caused by mutations in the retinitis pigmentosa GTPase regulator (
RPGR
) gene, which encodes a photoreceptor ciliary protein, and provide evidence that the therapy is effective. After subretinal injections of adeno-associated virus-2/5–vectored human
RPGR
with human IRBP or GRK1 promoters, in vivo imaging showed preserved photoreceptor nuclei and inner/outer segments that were limited to treated areas. Both rod and cone photoreceptor function were greater in treated (three of four) than in control eyes. Histopathology indicated normal photoreceptor structure and reversal of opsin mislocalization in treated areas expressing human RPGR protein in rods and cones. Postreceptoral remodeling was also corrected: there was reversal of bipolar cell dendrite retraction evident with bipolar cell markers and preservation of outer plexiform layer thickness. Efficacy of gene therapy in these large animal models of X-linked retinitis pigmentosa provides a path for translation to human treatment.
Neural correlates of the psychedelic state as determined by fMRI studies with psilocybin
Authors: Carhart-Harris Robin L. , Erritzoe David , Williams Tim , Stone James M. , Reed Laurence J. , Colasanti Alessandro , Tyacke Robin J. , Leech Robert , Malizia Andrea L. , Murphy Kevin , Hobden Peter , Evans John , Feilding Amanda , Wise Richard G. , Nutt David J.
Published: January 2012

Psychedelic drugs have a long history of use in healing ceremonies, but despite renewed interest in their therapeutic potential, we continue to know very little about how they work in the brain. Here we used psilocybin, a classic psychedelic found in magic mushrooms, and a task-free functional MRI (fMRI) protocol designed to capture the transition from normal waking consciousness to the psychedelic state. Arterial spin labeling perfusion and blood-oxygen level-dependent (BOLD) fMRI were used to map cerebral blood flow and changes in venous oxygenation before and after intravenous infusions of placebo and psilocybin. Fifteen healthy volunteers were scanned with arterial spin labeling and a separate 15 with BOLD. As predicted, profound changes in consciousness were observed after psilocybin, but surprisingly, only decreases in cerebral blood flow and BOLD signal were seen, and these were maximal in hub regions, such as the thalamus and anterior and posterior cingulate cortex (ACC and PCC). Decreased activity in the ACC/medial prefrontal cortex (mPFC) was a consistent finding and the magnitude of this decrease predicted the intensity of the subjective effects. Based on these results, a seed-based pharmaco-physiological interaction/functional connectivity analysis was performed using a medial prefrontal seed. Psilocybin caused a significant decrease in the positive coupling between the mPFC and PCC. These results strongly imply that the subjective effects of psychedelic drugs are caused by decreased activity and connectivity in the brain's key connector hubs, enabling a state of unconstrained cognition.
Uranyl peroxide enhanced nuclear fuel corrosion in seawater
Authors: Armstrong Christopher R. , Nyman May , Shvareva Tatiana , Sigmon Ginger E. , Burns Peter C. , Navrotsky Alexandra
Published: January 2012

The Fukushima-Daiichi nuclear accident brought together compromised irradiated fuel and large amounts of seawater in a high radiation field. Based on newly acquired thermochemical data for a series of uranyl peroxide compounds containing charge-balancing alkali cations, here we show that nanoscale cage clusters containing as many as 60 uranyl ions, bonded through peroxide and hydroxide bridges, are likely to form in solution or as precipitates under such conditions. These species will enhance the corrosion of the damaged fuel and, being thermodynamically stable and kinetically persistent in the absence of peroxide, they can potentially transport uranium over long distances.
Enabling high-temperature nanophotonics for energy applications
Authors: Yeng Yi Xiang , Ghebrebrhan Michael , Bermel Peter , Chan Walker R. , Joannopoulos John D. , Soljačić Marin , Celanovic Ivan
Published: January 2012

The nascent field of high-temperature nanophotonics could potentially enable many important solid-state energy conversion applications, such as thermophotovoltaic energy generation, selective solar absorption, and selective emission of light. However, special challenges arise when trying to design nanophotonic materials with precisely tailored optical properties that can operate at high-temperatures (> 1,100 K). These include proper material selection and purity to prevent melting, evaporation, or chemical reactions; severe minimization of any material interfaces to prevent thermomechanical problems such as delamination; robust performance in the presence of surface diffusion; and long-range geometric precision over large areas with severe minimization of very small feature sizes to maintain structural stability. Here we report an approach for high-temperature nanophotonics that surmounts all of these difficulties. It consists of an analytical and computationally guided design involving high-purity tungsten in a precisely fabricated photonic crystal slab geometry (specifically chosen to eliminate interfaces arising from layer-by-layer fabrication) optimized for high performance and robustness in the presence of roughness, fabrication errors, and surface diffusion. It offers near-ultimate short-wavelength emittance and low, ultra-broadband long-wavelength emittance, along with a sharp cutoff offering 4∶1 emittance contrast over 10% wavelength separation. This is achieved via
Q
-matching, whereby the absorptive and radiative rates of the photonic crystal’s cavity resonances are matched. Strong angular emission selectivity is also observed, with short-wavelength emission suppressed by 50% at 75° compared to normal incidence. Finally, a precise high-temperature measurement technique is developed to confirm that emission at 1,225 K can be primarily confined to wavelengths shorter than the cutoff wavelength.
Functional evidence that a recently evolved Drosophila sperm-specific gene boosts sperm competition
Authors: Yeh Shu-Dan , Do Tiffanie , Chan Carolus , Cordova Adriana , Carranza Francisco , Yamamoto Eugene A. , Abbassi Mashya , Gandasetiawan Kania A. , Librado Pablo , Damia Elisabetta , Dimitri Patrizio , Rozas Julio , Hartl Daniel L. , Roote John , Ranz José M.
Published: January 2012

In many species, both morphological and molecular traits related to sex and reproduction evolve faster in males than in females. Ultimately, rapid male evolution relies on the acquisition of genetic variation associated with differential reproductive success. Many newly evolved genes are associated with novel functions that might enhance male fitness. However, functional evidence of the adaptive role of recently originated genes in males is still lacking. The
Sperm dynein intermediate chain
multigene family, which encodes a Sperm dynein intermediate chain presumably involved in sperm motility, originated from complex genetic rearrangements in the lineage that leads to
Drosophila melanogaster
within the last 5.4 million years since its split from
Drosophila simulans
. We deleted all the members of this multigene family resident on the X chromosome of
D. melanogaster
by chromosome engineering and found that, although the deletion does not result in a reduction of progeny number, it impairs the competence of the sperm in the presence of sperm from wild-type males. Therefore, the
Sperm dynein intermediate chain
multigene family contributes to the differential reproductive success among males and illustrates precisely how quickly a new gene function can be incorporated into the genetic network of a species.
Local partnerships: blowing in the wind of national policy changes
Authors: Haynes Gill , Lynch Sarah
Published: January 2012

Drawing on data from a three‐year study (2008–2011) of partnerships of schools and colleges delivering the 14–19 Diplomas in England, this article examines how the dynamics of local partnerships were shaped by a contradictory policy landscape in which some policies strongly promoted collaborative working whilst others reinforced competition between institutions. Semi‐structured interviews with 136 Diploma consortium leads and case studies of 30 Diploma consortia were undertaken. Most partnerships founded in direct response to government demands for collaboration were strategically and operationally less effective than those that had been formed earlier as a positive, dynamic response to locally identified interests/needs and had evolved over time. When key levers towards collaboration were removed by the new UK Coalition government (2010) and new policies restated the arguments for institutional autonomy and competition between institutions, the fragility of the ‘enacted’ partnerships became immediately apparent. Although members of Diploma consortia with a history of effective partnership working remained committed to the principle of collaboration, other policy developments such as the introduction of the English Baccalaureate and the recommendations of the Wolf Review on vocational education contributed to uncertainty about whether partnership working could, or indeed should, be sustained.
Enchantment, possession and the uncanny in E.T.A. Hoffmann's ‘The Sandman’
Authors: Dawson Terence
Published: January 2012

All enchantment is a form of possession: as love or religious belief, it can invest a person’s life with significance; but as revenge or fanaticism, it can also bring about a fundamental change in the subject’s personality. Few writers have explored the tension between these different forms of enchantment more intriguingly than the German Romantic writer E.T.A. Hoffmann (1776–1822). Der Sandmann (“The Sandman”; 1816) is one his best-known tales, partly because it gave rise to favourites of the ballet and opera repertoires – Delibes’ Coppelia (1870), and one of the self-contained acts of Offenbach’s Les Contes d’Hoffmann (1881) – and partly owing to the enormous impact of the crucial section that Freud devoted to it in his essay on “The Uncanny” (1919). Although Freud’s views have been contested and re-articulated by a great many psychoanalytic critics, his essay continues to dominate literary discussion about this text. In this article, I show how a post-Jungian approach to Hoffmann’s celebrated text uncovers an unexpected reading of its concerns and a fresh way of thinking about narrative time. My aim is to propose that the tale has less to do with the events of Nathanael’s childhood than with the perils of enchantment in the present.
Comparative Analysis of Transcriptomic and Hormonal Responses to Compatible and Incompatible Plant-Virus Interactions that Lead to Cell Death
Authors: Pacheco Remedios , García-Marcos Alberto , Manzano Aranzazu , de Lacoba Mario García , Camañes Gemma , García-Agustín Pilar , Díaz-Ruíz José Ramón , Tenllado Francisco
Published: January 2012

Hypersensitive response-related programmed cell death (PCD) has been extensively analyzed in various plant–virus interactions. However, little is known about the changes in gene expression and phytohormone levels associated with cell death caused by compatible viruses. The synergistic interaction of Potato virus X (PVX) with a number of Potyvirus spp. results in increased symptoms that lead to systemic necrosis (SN) in Nicotiana benthamiana. Here, we show that SN induced by a PVX recombinant virus expressing a potyviral helper component-proteinase (HC-Pro) gene is associated with PCD. We have also compared transcriptomic and hormonal changes that occur in response to a compatible synergistic virus interaction that leads to SN, a systemic incompatible interaction conferred by the Tobacco mosaic virus-resistance gene N, and a PCD response conditioned by depletion of proteasome function. Our analysis indicates that the SN response clusters with the incompatible response by the similarity of their overall gene expression profiles. However, the expression profiles of both defense-related genes and hormone-responsive genes, and also the relative accumulation of several hormones in response to SN, relate more closely to the response to depletion of proteasome function than to that elicited by the incompatible interaction. This suggests a potential contribution of proteasome dysfunction to the increased pathogenicity observed in PVX–Potyvirus mixed infections. Furthermore, silencing of coronatine insensitive 1, a gene involved in jasmonate perception, in N. benthamiana accelerated cell death induced by PVX expressing HC-Pro.
Cross-Infection Experiments of Psittacanthus schiedeanus: Effects of Host Provenance, Gut Passage, and Host Fate on Mistletoe Seedling Survival
Authors: Ramírez María Magdalena , Ornelas Juan Francisco
Published: January 2012

Host-specific race formation has been suggested for mistletoe species using cross-dispersal experiments. Here, we tested the effects of host provenance, bird gut passage, and host fate on Psittacanthus schiedeanus seed either manually extracted or bird gut-passed on four host species in Veracruz, Mexico: Acacia pennatula, Liquidambar styraciflua, Platanus mexicana, and Quercus germana. Both groups of seed were placed on the branches of host trees in a full factorial design of cross-inoculation. Bird gut passage had no effect on seed germination, and the only factor having a significant effect on seed germination was host provenance. Results of seedling establishment were similar to those of seed germination, where mistletoe seed inoculated on P. mexicana were more likely to germinate and seedlings to establish than seed inoculated on the other hosts. The significant host provenance–fruit treatment interaction was largely due to a lower seedling establishment of gut-passed seed from P. mexicana to P. mexicana and the other hosts. Although host provenance of mistletoe seed was a significant predictor in germination and seedling establishment, the host provenance–host fate interaction was the only significant predictor for seedling survival. The significant host provenance–host fate interaction was largely due to higher survival success of mistletoe seed from L. styraciflua to L. styraciflua and P. mexicana and from P. mexicana to P. mexicana and a lower success from Q. germana to Q. germana and from A. pennatula to A. pennatula.
A Comparison of Epidural Analgesia and Traditional Pain Management Effects on Survival and Cancer Recurrence after Colectomy
Authors: Cummings Kenneth C. , Xu Fang , Cummings Linda C. , Cooper Gregory S.
Published: January 2012

Background

Cancer recurrence after surgery may be affected by immunosuppressive factors such as surgical stress, anesthetic drugs, and opioids. By limiting exposure to these, epidural analgesia may enhance tumor surveillance. This study compared survival and cancer recurrence rates for resection of colorectal cancer between patients who received perioperative epidurals and those who did not.

Methods

The linked Medicare-Surveillance, Epidemiology, and End Results database was used to identify patients ages 66 yr or older with nonmetastatic colorectal cancer diagnosed between 1996 and 2005 who underwent open colectomy. Recurrence was defined as chemotherapy 16 months or more after surgery and/or radiation 12 months or more after surgery. Patients were followed for at least 4 yr. To account for hospital effects, overall survival was estimated via marginal Cox regression. Recurrence was estimated by conditional logistic regression.

Results

A cohort of 42,151 patients, of whom 22.9% (n = 9,670) had epidurals at the time of resection, was identified. 5-yr survival was 61% in the epidural group and 55% in the nonepidural group. There was a significant association between epidural use and improved survival (adjusted Cox model hazard ratio = 0.91, 95% CI = [0.87, 0.94]). Adjusting for covariates, there was no significant reduction of recurrence in the epidural group (odds ratio = 1.05, 95% CI = [0.95, 1.15]). Several covariates, including blood transfusion, were predictive of mortality and cancer recurrence.

Conclusion

This large cohort study found that epidural use is associated with improved survival in patients with nonmetastatic colorectal cancer undergoing resection but does not support an association between epidural use and decreased cancer recurrence.