bluuebunny/crossref_metadata_2025 huggingface dataset:
Impact of birth rate, seasonality and transmission rate on minimum levels of coverage needed for rubella vaccination
Authors: METCALF C. J. E. , LESSLER J. , KLEPAC P. , CUTTS F. , GRENFELL B. T.
Published: February 2012

Childhood rubella infection in early pregnancy can lead to fetal death or congenital rubella syndrome (CRS) with multiple disabilities. Reduction of transmission via universal vaccination can prevent CRS, but inadequate coverage may increase CRS numbers by increasing the average age at infection. Consequently, many countries do not vaccinate against rubella. The World Health Organization recommends that for safe rubella vaccination, at least 80% coverage of each birth cohort should be sustained. The nonlinear relationship between CRS burden and infection dynamics has been much studied; however, how the complex interaction between epidemic and demographic dynamics affects minimum safe levels of coverage has not been quantitatively evaluated across scales necessary for a global assessment. We modelled 30-year CRS burdens across epidemiological and demographic settings, including the effect of local interruption of transmission via stochastic fadeout. Necessary minimum vaccination coverage increases markedly with birth and transmission rates, independent of amplitude of seasonal fluctuations in transmission. Susceptible build-up in older age groups following local stochastic extinction of rubella increased CRS burden, indicating that spatial context is important. In low birth-rate settings, 80% routine coverage is a conservative guideline, particularly if supplemented with campaigns and vaccination of women of childbearing age. Where birth and transmission rates are high, immunization coverage must be well above 80% and campaigns may be needed. Policy-makers should be aware of the potential negative effect of local extinction of rubella, since heterogeneity in vaccination coverage will shape extinction patterns, potentially increasing CRS burdens.
Contribution of tropical cyclones to the air‐sea CO2 flux: A global view
Authors: Lévy M. , Lengaigne M. , Bopp L. , Vincent E. M. , Madec G. , Ethé C. , Kumar D. , Sarma V. V. S. S.
Published: February 2012

Previous case studies have illustrated the strong local influence of tropical cyclones (TCs) on CO2 air‐sea flux suggesting that they can significantly contribute to the global In this study, we use a state‐of‐the art global ocean biochemical model driven by TCs wind forcing derived from a historical TCs database, allowing to sample the response under 1663 TCs. Our results evidence a very weak contribution of TCs to global one or two order of magnitude smaller than previous estimates extrapolated from case studies. This result arises from several competing effects involved in the response to TCs, not accounted for in previous studies. While previous estimates have hypothesized the ocean to be systematically oversaturated in CO2 under TCs, our results reveal that a similar proportion of TCs occur over oversaturated regions (i.e. the North Atlantic, Northeast Pacific and the Arabian Sea) and undersaturated regions (i.e. Westernmost North Pacific, South Indian and Pacific Ocean). Consequently, by increasing the gas exchange coefficient, TCs can generate either instantaneous CO2 flux directed from the ocean to the atmosphere (efflux) or the opposite (influx), depending on the CO2 conditions at the time of the TC passage. A large portion of TCs also occurs over regions where the ocean and the atmosphere are in near equilibrium, resulting in very weak instantaneous fluxes. Previous estimates also did not account for any asynchronous effect of TCs on during several weeks after the storm, oceanic pCO2 is reduced in response to vertical mixing, which systematically causes an influx anomaly. This implies that, contrary to previous estimates, TCs weakly affect the CO2 efflux when they blow over supersaturated areas because the instantaneous storm wind effect and post‐storm mixing effect oppose with each other. In contrast, TCs increase the CO2 influx in undersaturated conditions because the two effects add up. These compensating effects result in a very weak contribution to global and a very modest contribution to regional interannual variations (up to 10%).
Global variations in H2O/Ce: 2. Relationships to arc magma geochemistry and volatile fluxes
Authors: Ruscitto Daniel M. , Wallace Paul J. , Cooper Lauren B. , Plank Terry
Published: February 2012

We compiled a data set of 100 primitive arc magma compositions from melt inclusion and whole rock analyses to compare volatile contents, slab tracers, and calculated subduction component compositions between 18 subduction zone segments spanning the global range in slab thermal structure. The average primitive magma H2O content in our data set is 3.3 ± 1.2 wt.% (1 s.d.) for melts erupted within 50 km of the volcanic front. While there is a wide range of volatile contents in magmas within individual arcs, the highest values occur in magmas erupted from vents along the volcanic front, where the subducting slab is located 104 ± 29 km (avg ± 1 s.d.) beneath the surface. This observation, coupled with positive correlations between H2O, Cl, S, and B contents and predictions from geodynamic models, provides strong evidence for the active supply of volatile‐rich slab‐derived components from the subducting oceanic plate beneath volcanic arcs. We also show that temperature‐sensitive ratios (e.g., H2O/Ce) for both primitive arc magmas and calculated subduction components are similar and display monotonic behavior with slab thermal parameter. Furthermore, calculated subduction component compositions have higher trace element to H2O ratios in arcs with hotter slabs (lower thermal parameter), suggesting that hydrous melts of differing compositions are added beneath different arcs. Finally, we present new volatile outflux estimates for Central Cascades magmatism and then compare these to estimates for the Central American and Kamchatka‐Kurile arcs to create a combined data set spanning a large range in slab thermal parameter.
Spectral character of VLF sferics propagating inside the Earth‐ionosphere waveguide during two recent solar eclipses
Authors: Guha Anirban , De Barin Kumar , Choudhury Abhijit , Roy Rakesh
Published: February 2012

Effects of solar eclipses on the propagation characteristics of worldwide VLF sferics from lightning activity require more investigation. An attempt was made on the occasion of two solar eclipses during 22nd July, 2009 and 15th January, 2010 to study the effects of the two eclipses on the propagation characteristics of VLF sferics in the Earth‐ionosphere waveguide. Identical experimental setups were used to study the VLF sferics during the two eclipse events. The spectral character of VLF sferics propagating inside the waveguide is studied at a fixed receiver location (23.75°N, 91.25°E) at six discrete frequencies in between 3 and 20 kHz. During both the eclipse events, it is observed that VLF sferics at all the six discrete frequencies is increased from the mean normal average ambient level. The increment peaks around 10–12 kHz with an overall increment of 6.4 dB with respect to its ambient level. The VLF spectral character of enhancement of sferics show similar characters in two eclipses. The percentage decrease in electron density using standard modeling equations is found to be 90% at the height of 71 km for both the eclipses, supporting linear variation of electron density with solar radiation at the D‐region of the ionosphere. The results are explained qualitatively on the basis of a decrease in electron density at the lower ionosphere modifying the reflection coefficient which affected the propagation of VLF sferics in Earth‐ionosphere waveguide during eclipsed condition.
Moisture fluxes derived from EOS aqua satellite data for the north water polynya over 2003–2009
Authors: Boisvert Linette N. , Markus Thorsten , Parkinson Claire L. , Vihma Timo
Published: February 2012

Satellite data were applied to calculate the moisture flux from the North Water polynya during a series of events spanning 2003–2009. The fluxes were calculated using bulk aerodynamic formulas with the stability effects according to the Monin‐Obukhov similarity theory. Input parameters were taken from three sources: air relative humidity, air temperature, and surface temperature from the Atmospheric Infrared Sounder (AIRS) on board NASA's Earth Observing System (EOS) Aqua satellite, sea ice concentration from the Advanced Microwave Scanning Radiometer for EOS (AMSR‐E, also on board Aqua), and wind speed from the European Centre for Medium‐Range Weather Forecasts ERA‐Interim reanalysis. Our results show the progression of the moisture fluxes from the polynya during each event, as well as their atmospheric effects after the polynya has closed up. These results were compared to results from studies on other polynyas and fall within one standard deviation of the moisture flux estimates from these studies. Although the estimated moisture fluxes over the entire study region from AIRS are smaller in magnitude than those from ERA‐Interim, they are more accurate owing to improved temperature and relative humidity profiles and ice concentration estimates over the polynya. Error estimates were calculated to be 5.56 × 10−3 g m−2 s−1, only 25% of the total moisture flux, thus suggesting that AIRS and AMSR‐E can be used with confidence to study smaller‐scale features in the Arctic sea ice pack and can capture their atmospheric effects. These findings bode well for larger‐scale studies of moisture fluxes over the entire Arctic Ocean and the thinning ice pack.
PTR‐MS observations of photo‐enhanced VOC release from Arctic and midlatitude snow
Authors: Gao S. S. , Sjostedt S. J. , Sharma S. , Hall S. R. , Ullmann K. , Abbatt J. P. D.
Published: February 2012

To evaluate the release mechanism of volatile organic species (VOCs) from solar illuminated snowpacks, this study used proton transfer reaction–mass spectrometry (PTR‐MS) for the first time to study VOCs within Arctic snow and to compare these results to VOC release from illuminated snow in the laboratory. The field measurements were conducted in April during the 2009 Ocean–Atmosphere–Sea Ice–Snowpack (OASIS) campaign in Barrow, Alaska, whereas in the laboratory four natural snow samples, from the Arctic (Alert, Nunavut), a rural site (Egbert, Ontario), and an urban area (Toronto, Ontario), were exposed to a Xe arc lamp with a 295 nm longpass filter. Similar VOCs were observed in both the field and laboratory experiments suggesting that these light‐driven processes occur not only in polar regions but in midlatitude snows as well. Also, because the laboratory samples were temperature controlled, we conclude that the release mechanism is primarily photochemical and not temperature mediated. The snow composition may have influenced VOC production because aged Toronto snow samples, with both the highest total organic carbon content and concentration of oxidant precursors (i.e., NO3−), exhibited the largest production of VOCs upon irradiation.
Complex waves on periodic arrays of lossy and lossless permeable spheres: 1. Theory
Authors: Shore Robert A. , Yaghjian Arthur D.
Published: February 2012

This is the first part of a two‐part series dealing with complex dipolar waves propagating along the axes of 1D, 2D, and 3D infinite periodic arrays of small lossless and lossy permeable spheres. The theory is presented in this paper and numerical results are presented by Shore and Yaghjian (2012). The focus is on the dispersion (k–β) equations relating the array propagation constant, β, to the free‐space wave number,k, for dipolar complex waves. The k–β equation for the complex propagation constants of a given array is obtained from the corresponding equation previously obtained for the real propagation constants by rewriting the real propagation dispersion equation in a form that can be analytically continued into the complex β plane. This equation reduces correctly to the real β dispersion equation and enables complex values of β to be found as a function of the array element parameters. By allowing for all the possible branches of the multivalued homogeneous dispersion equation analytically continued into the complex βplane, the propagation constants of all the improper as well as proper complex waves supported by the 1D, 2D, and 3D arrays are found from the homogeneous solutions for these arrays. Green's functions for external sources are not required to find the propagation constants of the complex waves supported by the arrays. For 3D arrays, in certain frequency ranges, it is possible to regard the arrays as media characterized by bulk or effective permittivities and permeabilities. Expressions for these bulk parameters, more accurate than the Clausius‐Mossotti expressions, are obtained from quantities readily available in the solutions of the dispersion equations.
Viscosity dependent dual‐permeability modeling of liquid manure movement in layered, macroporous, tile drained soil
Authors: Frey Steven K. , Rudolph David L. , Lapen David R. , Ball Coelho Bonnie R.
Published: February 2012

A scarcity of information exists on how physical processes govern the movement of liquid manure, or other viscous fluids, through layered macroporous soils. To elucidate these complex flow and transport phenomena, a viscosity dependent, two‐dimensional dual‐permeability model that considers macropore anisotropy is employed to simulate field experiments where liquid swine manure (LSM) was applied to silt loam with both a soil crust and plowpan layer present. Using data from the field experiment as a benchmark, the model was used to predict nutrient (NH4‐N and total P) breakthrough to tile drains; and to assess the influence of reduced permeability crust and plowpan layers, and fluid viscosity, on solute movement within 48 h of LSM application. Results demonstrate the importance of viscosity on flow and transport in macroporous soils. By increasing LSM viscosity, nutrient breakthrough to tile drains can be greatly reduced, and near surface nutrient retention can increase. The presence of a nonmacroporous soil crust layer can also lead to reduced nutrient concentrations in tile discharge by reducing pressure heads in the underlying A‐horizon soil matrix, resulting in reduced macropore flow; whereas a low permeability plowpan layer at the base of the A horizon can increase pressure heads in the A‐horizon soil matrix and lead to increased macropore flow. Multiple target point parameter sensitivity analysis revealed that relative parameter sensitivity can be a transient characteristic, and that hydraulic properties of the A and B horizon tend to exhibit their greatest influence over the respective early and late time solute breakthrough characteristics.
ENSO prediction one year in advance using western North Pacific sea surface temperatures
Authors: Wang Shih‐Yu , L'Heureux Michelle , Chia Hsin‐Hsing
Published: February 2012

We present evidence that the de‐trended, boreal winter sea surface temperature anomalies (SSTA) in the western North Pacific (WNP) are a skillful predictor for the development of the El Niño‐Southern Oscillation (ENSO) by the following winter. The WNP shares some similarities with the Meridional Mode (MM) located in the subtropical central and eastern North Pacific: both are linked to off‐equatorial SSTA and low‐level wind anomalies, and both appear to be strongly related to wintertime variability in the North Pacific Oscillation (NPO). However, in contrast with the MM, the WNP is associated with an opposite‐signed SSTA dipole located off southeastern Asia and in the western tropical Pacific, which is accompanied by equatorial winds that may influence the level of oceanic Kelvin wave activity that precedes ENSO events.
Transthyretin is a metallopeptidase with an inducible active site
Authors: Liz Márcia A. , Leite Sérgio C. , Juliano Luiz , Saraiva Maria J. , Damas Ana M. , Bur Daniel , Sousa Mónica M.
Published: February 2012

TTR (transthyretin) was found recently to possess proteolytic competency besides its well-known transport capabilities. It was described as a cryptic serine peptidase cleaving multiple natural substrates (including β-amyloid and apolipoprotein A-I) involved in diseases such as Alzheimer's disease and atherosclerosis. In the present study, we aimed to elucidate the catalytic machinery of TTR. All attempts to identify a catalytic serine residue were unsuccessful. However, metal chelators abolished TTR activity. Proteolytic inhibition by EDTA or 1,10-phenanthroline could be reversed with Zn2+ and Mn2+. These observations, supported by analysis of three-dimensional structures of TTR complexed with Zn2+, led to the hypothesis that TTR is a metallopeptidase. Site-directed mutagenesis of selected amino acids unambiguously confirmed this hypothesis. The TTR active site is inducible and constituted via a protein rearrangement resulting in ~7% of proteolytically active TTR at pH 7.4. The side chain of His88 is shifted near His90 and Glu92 establishing a Zn2+-chelating pattern HXHXE not found previously in any metallopeptidase and only conserved in TTR of humans and some other primates. Point mutations of these three residues yielded proteins devoid of proteolytic activity. Glu72 was identified as the general base involved in activation of the catalytic water. Our results unveil TTR as a metallopeptidase and define its catalytic machinery.
Reduced Speech Perceptual Acuity for Stop Consonants in Individuals Who Stutter
Authors: Neef Nicole E. , Sommer Martin , Neef Andreas , Paulus Walter , von Gudenberg Alexander Wolff , Jung Kristina , Wüstenberg Torsten
Published: February 2012

Purpose

In individuals who stutter (IWS), speech fluency can be enhanced by altered auditory feedback, although it has adverse effects in control speakers. This indicates abnormalities in the auditory feedback loop in stuttering. Current motor control theories on stuttering propose an impaired processing of internal forward models that might be related to a blurred auditory-to-motor translation. Although speech sound perception is an essential skill to form internal models, perceptual acuity has not been studied in IWS so far. The authors tested the stability of phoneme percepts by analyzing participants' ability to identify voiced and voiceless stop consonants.

Method

Two syllable continua were generated by systematic modification of the voice onset time. The authors determined speech perceptual acuity by means of discriminatory power in 25 IWS and 24 matched control participants by determining the phoneme boundaries and by quantifying the interval of voice onset times for which phonemes were perceived ambiguously.

Results

In IWS, discriminatory performance was weaker and less stable over time when compared with control participants. In addition, phoneme boundaries were located at longer voice onset times in IWS.

Conclusion

Persistent developmental stuttering is associated with less reliable phonological percepts, supporting current theories regarding the sensory–motor interaction in human speech.

Supplemental Material

https://doi.org/10.23641/asha.6170357
Gesture and Naming Therapy for People With Severe Aphasia: A Group Study
Authors: Marshall Jane , Best Wendy , Cocks Naomi , Cruice Madeline , Pring Tim , Bulcock Gemma , Creek Gemma , Eales Nancy , Mummery Alice Lockhart , Matthews Niina , Caute Anna
Published: February 2012

Purpose

In this study, the authors (a) investigated whether a group of people with severe aphasia could learn a vocabulary of pantomime gestures through therapy and (b) compared their learning of gestures with their learning of words. The authors also examined whether gesture therapy cued word production and whether naming therapy cued gestures.

Method

Fourteen people with severe aphasia received 15 hr of gesture and naming treatments. Evaluations comprised repeated measures of gesture and word production, comparing treated and untreated items.

Results

Baseline measures were stable but improved significantly following therapy. Across the group, improvements in naming were greater than improvements in gesture. This trend was evident in most individuals' results, although 3 participants made better progress in gesture. Gains were item specific, and there was no evidence of cross-modality cueing. Items that received gesture therapy did not improve in naming, and items that received naming therapy did not improve in gesture.

Conclusions

Results show that people with severe aphasia can respond to gesture and naming therapies. Given the unequal gains, naming may be a more productive therapy target than gesture for many (although not all) individuals with severe aphasia. The communicative benefits of therapy were not examined but are addressed in a follow-up article.
Statistical Learning in Emerging Lexicons: The Case of Danish
Authors: Stokes Stephanie F. , Bleses Dorthe , Basbøll Hans , Lambertsen Claus
Published: February 2012

Purpose

This research explored the impact of neighborhood density (ND), word frequency (WF), and word length (WL) on the vocabulary size of Danish-speaking children. Given the particular phonological properties of Danish, the impact was expected to differ from that reported in studies on English and French.

Method

The monosyllabic words in the expressive lexicons of 894 Danish-speaking 2-year-old children were coded for ND, WF, and WL. Lexicons were extracted from parent checklists of the words spoken by their children.

Results

Regression revealed that ND, WF, WL, and age together predicted 47% of the variance in vocabulary size, with ND, WF, WL, and age uniquely accounting for 39%, 3.2%, 2.2%, and 2.8% of that variance, respectively. Children with small vocabularies had learned words that were denser and more frequent in the ambient language, and those words were shorter than the words of children with larger vocabularies.

Conclusion

The 2 main findings were unexpected. The impact of ND for Danish-speaking children was not expected given the phonological properties of the language. The WF results differed from those of English because of the distribution of word classes on the language-relevant parent checklists. The strong role for ND in emerging languages found in other languages was replicated for Danish.
Auditory Frequency Discrimination in Adults With Dyslexia: A Test of the Anchoring Hypothesis
Authors: Wijnen Frank , Kappers Astrid M. L. , Vlutters Leoni D. , Winkel Sven
Published: February 2012

Purpose

A recent hypothesis ascribes dyslexia to a perceptual anchoring deficit. Supporting results have so far been obtained only in children with dyslexia and additional learning difficulties, but the hypothesis has been argued to apply to all individuals with dyslexia.

Method

The authors measured auditory frequency discrimination thresholds in 54 young adults (native speakers of Dutch; 25 individuals with dyslexia; 29 age- and education-matched controls), with a 2-alternative forced-choice staircase paradigm. There were 2 conditions: 1 in which 1 tone in each pair had a fixed frequency across trials (standard), and 1 in which both tones varied in frequency (no standard). Presence of a standard stimulus allows the creation of a stimulus-specific representation in short-term-memory (perceptual anchor).

Results

The standard condition yielded significantly lower discrimination thresholds in both controls and individuals with dyslexia; both groups benefited equally from the presence of an invariant stimulus.

Conclusion

There is no difference between this group of adults with dyslexia and controls in their capacity to form a perceptual anchor. The implication is that an anchoring deficit cannot be generalized to all cases of dyslexia.
Production of multi-MeV Bremsstrahlung x-ray sources by petawatt laser pulses on various targets
Authors: Compant La Fontaine A. , Courtois C. , Lefebvre E.
Published: February 2012

During the interaction of a high-intensity picosecond laser pulse with a plasma, a large amount of relativistic electrons are accelerated. If these electrons interact with a high-Z solid target, Bremsstrahlung photons are generated. This multi-MeV x-ray source may be used in various applications including radiography and photonuclear studies. The characteristics of such sources, produced with a petawatt laser interacting with different targets, are investigated numerically, using laser-plasma interaction and transport codes to model the relativistic electron acceleration and their transport in the conversion target, respectively. If the laser pulse interacts with a preplasma in front of a solid target, the on-axis dose first increases with preplasma scale-length, but then saturates and fluctuates, due to strong filamentation of the petawatt pulse. In an ionized gas jet, laser hosing reduces the electron emission along the propagation direction and thus the dose. For a capillary tube filled with plasma, the laser pulse is well confined along the axis and a net increase of the on-axis dose is obtained. The X-spot size obtained for these different cases varies from 20 μm to a few hundred microns.
Excitation of zonal flow and magnetic field by Rossby–Khantadze electromagnetic planetary waves in the ionospheric E-layer
Authors: Kaladze T. D. , Kahlon L. Z. , Tsamalashvili L. V.
Published: February 2012

Nonlinear dynamics of Rossby–Khantadze electromagnetic planetary waves in the weakly ionized ionospheric E-layer is investigated. Along with the prevalent effect of Hall conductivity for these waves, the latitudinal inhomogeneity of both the Earth’s angular velocity and the geomagnetic field becomes essential. It is shown that such short wavelength turbulence of Rossby–Khantadze waves is unstable with respect to the excitation of low-frequency and large-scale perturbations of the zonal flow and magnetic field. The nonlinear mechanism of the instability is driven by the advection of vorticity, leading to the inverse energy cascade toward the longer wavelength. The growth rate of the corresponding instability is found. It is shown that the generation of the intense mean magnetic field is caused by the latitudinal gradient of the geomagnetic field.
The dynamics of hot-electron heating in direct-drive-implosion experiments caused by two-plasmon-decay instability
Authors: Myatt J. F. , Zhang J. , Delettrez J. A. , Maximov A. V. , Short R. W. , Seka W. , Edgell D. H. , DuBois D. F. , Russell D. A. , Vu H. X.
Published: February 2012

Two-plasmon-decay (TPD) instability is identified as a potential source of target preheat in direct-drive-implosion experiments on OMEGA. A physical model of electron heating is developed that relies on extended Zakharov simulations to predict the nonlinearly saturated Langmuir wave spectrum. Hot electron generation is estimated via a test-particle approach. It is noted that because of the relatively low areal density of the targets during the time of TPD instability, hot-electron recirculation and reheating are potentially important effects. This is modeled by a particular form of boundary conditions on the test particles. Such boundary conditions might prove useful in other kinetic simulations of particle heating where recirculation is a possibility.
Thermal force drift wave
Authors: Hung C. P. , Hassam A. B.
Published: February 2012

A drift instability of a collisional magnetized plasma, unstable due to the Braginskii thermal force but not requiring any direct dissipation such as resistivity or electron inertia, is examined. Unlike conventional drift-modes, the maximum growth rate of the thermal force drift wave (TFDW) is of order the drift frequency, making for a strongly turbulent nonlinear state. A 3D, magnetized two-fluid code is developed to allow the study of both ideal MHD modes as well as lower frequency drift modes. The governing equations are essentially the ideal MHD equations with the inclusion of Hall and thermal force terms in Ohm’s law. This set of equations is reduced in a finite β, long parallel wavelength, and small but significant Larmor radius ordering and tested for shear Alfven waves, parallel sound waves, and drift modes. The code is employed to recover the TFDW instability, to verify the code against the mode’s analytic linear characteristics, and to study the nonlinear behavior of the TFDW. The TFDW growth is strongly suppressed by parallel thermal conduction and thus this mode is more likely to be observed in low temperature plasmas.
Ion beam neutralization and properties of plasmas from low power ring cusp ion thrusters
Authors: Criado E. , Roibás E. , Tierno S. P. , Rodríguez De Francisco P. , Domenech-Garret J. L. , Donoso J. M. , Conde L.
Published: February 2012

The design and operation modes of a small, low power ion plasma thruster and the properties of the emitted plasma plumes are discussed. The ion beam is extracted from a primary plasma produced by a stationary low pressure electric discharge where the ion production rate is essentially determined by the discharge current. The experiments evidence that the electron neutralization current controls the space charge levels of the outgoing ion current and also influences the spatial properties of emitted plasmas. The electron plasma density increases with the discharge and the electron neutralization currents, while decreases as the plasma plume expands. However, the corresponding electron temperatures decrease when the electron neutralization currents increments. The collisional origin of this electron cooling effect is excluded because of the large collisional mean free paths involved. Then, these electron energy losses during the neutralization of the ion beam would be caused by more subtle physical mechanisms than collisions. The experimental results are compared with previous numerical simulations and similar phenomena found in other experiments.
Hole effective masses of p-type metal-oxide-semiconductor inversion layer in strained Si1-xGex alloys channel on (110) and (111) Si substrates
Authors: Chang Shu-Tong , Wei Fan Jun , Lin Chung-Yi , Cho Ta-Chun , Huang Ming
Published: February 2012

Valence subband properties and hole effective masses of PMOS inversion layer in strained Si1-xGex alloys channel on (110) and (111) Si substrates are studied theoretically based on the Luttinger-Kohn Hamiltonian. The subband structures under investigation are a result of the quantized levels produced by the triangular quantum well in the inversion layer created by the applied gate bias in the z-direction. Valence subband properties including constant-energy-contours, density-of-states, quantized effective mass in the z-direction mz, carrier concentration effective mass mcc, and conductivity effective mass mσ are calculated as functions of the Ge concentration at gate electric field of 1 MV/cm. An analytic expression for the Fermi level is derived in terms of mcc, the total hole concentration, and subband edges. Our results show that in general mσ in the (110) system is lower than that in the (111) substrate orientation, which implies that (110) Si substrate is more favorable for carrier transport. Furthermore, mσ in the [−110] direction of the (110) Si substrate system are the lightest among all other cases.
Memory effects in superparamagnetic and nanocrystalline Fe50Ni50 alloy
Authors: De D. , Karmakar A. , Bhunia M. K. , Bhaumik A. , Majumdar S. , Giri S.
Published: February 2012

Nanocrystalline Fe50Ni50 alloy is prepared using the sol-gel route in an amorphous silica host at different volume fractions (φ). The average particle size is 8.9 nm having log-normal distribution = 0.19, which is confirmed by transmission electron microscopy for φ = 1%. The blocking temperature (TB) is 30 K, as observed in dc magnetization. The frequency-dependent peak-shift in ac susceptibility satisfies Néel-Arrhenius formalism with more reasonable physical parameters than Vogel-Fulcher and dynamical scaling formalisms. Analysis of the relaxation dynamics below TB points toward weak interparticle interaction, signifying superparamagnetic behavior. Relaxation dynamics following stretched exponential function implies that it is involved with the activation against multiple anisotropy barriers, which is correlated to the distribution of particle size. Memory effects are observed in different experimental protocols below TB, which has been discussed pertaining to superparamagnetic behavior.
Magnetic-enhanced electron-phonon coupling and vacancy effect in “111”-type iron pnictides from first-principle calculations
Authors: Li B. , Xing Z. W. , Huang G. Q. , Liu M.
Published: February 2012

We investigate the lattice dynamics in both nonmagnetic and striped antiferromagnetic states of “111”-type iron pnictides using the density-functional perturbation theory. The anisotropic spin-phonon effects lead to the softening of phonon frequencies and the renormalization of electron-phonon matrix elements, so as to increase the electron-phonon couplings by 68%, 65%, and 0.9% for LiFeAs, NaFeAs, and LiFeP, respectively. Taking into account the vacancy effects in the three iron pnictides, we find that the electron-phonon couplings are further enhanced by hole doping, yielding superconducting transition temperatures close to their experimental values.
Insulin-like growth factor-binding protein 2-driven glioma progression is prevented by blocking a clinically significant integrin, integrin-linked kinase, and NF-κB network
Authors: Holmes Kristen M. , Annala Matti , Chua Corrine Y. X. , Dunlap Sarah M. , Liu Yuexin , Hugen Niek , Moore Lynette M. , Cogdell David , Hu Limei , Nykter Matti , Hess Kenneth , Fuller Gregory N. , Zhang Wei
Published: February 2012

Insulin-like growth factor-binding protein 2 (IGFBP2) is increasingly recognized as a glioma oncogene, emerging as a target for therapeutic intervention. In this study, we used an integrative approach to characterizing the IGFBP2 network, combining transcriptional profiling of human glioma with validation in glial cells and the replication-competent ASLV long terminal repeat with a splice acceptor/tv-a glioma mouse system. We demonstrated that IGFBP2 expression is closely linked to genes in the integrin and integrin-linked kinase (ILK) pathways and that these genes are associated with prognosis. We further showed that IGFBP2 activates integrin β1 and downstream invasion pathways, requires ILK to induce cell motility, and activates NF-κB. Most significantly, the IGFBP2/integrin/ILK/NF-κB network functions as a physiologically active signaling pathway in vivo by driving glioma progression; interfering with any point in the pathway markedly inhibits progression. The results of this study reveal a signaling pathway that is both targetable and highly relevant to improving the survival of glioma patients.
Site-specific DNA-antibody conjugates for specific and sensitive immuno-PCR
Authors: Kazane Stephanie A. , Sok Devin , Cho Edward H. , Uson Maria Loressa , Kuhn Peter , Schultz Peter G. , Smider Vaughn V.
Published: February 2012

Antibody conjugates are widely used as diagnostics and imaging reagents. However, many such conjugates suffer losses in sensitivity and specificity due to nonspecific labeling techniques. We have developed methodology to site-specifically conjugate oligonucleotides to antibodies containing a genetically encoded unnatural amino acid with orthogonal chemical reactivity. These oligobody molecules were used in immuno-PCR assays to detect Her2
+
cells with greater sensitivity and specificity than nonspecifically coupled fragments, and can detect extremely rare Her2
+
cells in a complex cellular environment. Such designed antibody-oligonucleotide conjugates should provide sensitive and specific reagents for diagnostics, as well as enable other unique applications based on oligobody building blocks.
Nuclear receptor Nr4a1 modulates both regulatory T-cell (Treg) differentiation and clonal deletion
Authors: Fassett Marlys S. , Jiang Wenyu , D'Alise Anna Morena , Mathis Diane , Benoist Christophe
Published: February 2012

Immature thymocytes expressing autoreactive T-cell receptors (TCR) can adopt differing cell fates: clonal deletion by apoptosis or deviation into alternative lineages such as FoxP3+regulatory T cells (Treg). We revisited the role of the transcription factor Nr4a1 (Nur77), an immediate-early response gene induced by TCR engagement. Nr4a1KO mice show clear quantitative defects in antigen-induced clonal deletion. The impact of the Nr4a1 deletion is not enhanced by deletion of the proapoptotic factor Bim. In addition, Nr4a1 curtails initial differentiation into the Treg lineage in TCR transgenic mice and in nontransgenic mice. Transcriptional profiling of Nr4a1KO thymocytes under selection conditions reveals that Nr4a1 activates the transcription of several targets, consistent with these diverse actions: (i) Nr4a1 partakes in the induction of Bim after TCR triggering; (ii) perhaps paradoxically, Nr4a1 positively controls several transcripts of the Treg signature, in particularIkzf2andTnfrsf9; (iii) consistent with its prosurvival and metabolic role in the liver, Nr4a1 is also required for the induction by TCR of a coordinated set of enzymes of the glycolytic and Krebs cycle pathways, which we propose may antagonize Treg selection as does activation of mTOR/Akt. Thus, Nr4a1 appears to act as a balancing molecule in fate determination at a critical juncture of T-cell differentiation.
Simulation of main chamber wall temperature rise resulting from massive neon gas injection shutdown of ITER
Authors: Hollmann E.M. , Humphreys D.A. , Parks P.B.
Published: February 2012

Simulations were performed to estimate the main chamber wall heating in ITER resulting from rapid discharge shutdown by neon massive gas injection (MGI). The TokSys current diffusion model coupled with a simplified impurity transport model was used. Impurity parallel flow was treated with a single-fluid pressure-driven flow model. Impurity cross-field diffusion was treated with an empirical diffusion coefficient estimated from present experiments, while impurity poloidal rotation was included empirically by extrapolation in minor radius from present experiments to ITER. For single-valve neon MGI, maximum wall temperatures of order 1100 K are predicted, somewhat below the melting temperature of beryllium (1560 K). Lower temperature excursions were obtained by increasing the number of gas valves, while higher wall temperatures could be obtained by turning up initial plasma thermal energy or cross-field transport coefficients. Highest wall temperatures tended to occur on the centre post during the start of the current quench phase, consistent with present experiments. These results suggest that a single port may be sufficient for safely initiating rapid shutdown in ITER, leaving other ports free for subsequent rapid shutdown tasks such as runaway electron mitigation.
Simulation of Alfvén eigenmode bursts using a hybrid code for nonlinear magnetohydrodynamics and energetic particles
Authors: Todo Y. , Berk H.L. , Breizman B.N.
Published: February 2012

A hybrid simulation code for nonlinear magnetohydrodynamics (MHD) and energetic-particle dynamics has been extended to simulate recurrent bursts of Alfvén eigenmodes by implementing the energetic-particle source, collisions and losses. The Alfvén eigenmode bursts with synchronization of multiple modes and beam ion losses at each burst are successfully simulated with nonlinear MHD effects for the physics condition similar to a reduced simulation for a TFTR experiment (Wong et al 1991 Phys. Rev. Lett.
66 1874, Todo et al 2003 Phys. Plasmas
10 2888). It is demonstrated with a comparison between nonlinear MHD and linear MHD simulation results that the nonlinear MHD effects significantly reduce both the saturation amplitude of the Alfvén eigenmodes and the beam ion losses. Two types of time evolution are found depending on the MHD dissipation coefficients, namely viscosity, resistivity and diffusivity. The Alfvén eigenmode bursts take place for higher dissipation coefficients with roughly 10% drop in stored beam energy and the maximum amplitude of the dominant magnetic fluctuation harmonic δB

m/n
/B ∼ 5 × 10−3 at the mode peak location inside the plasma. Quadratic dependence of beam ion loss rate on magnetic fluctuation amplitude is found for the bursting evolution in the nonlinear MHD simulation. For lower dissipation coefficients, the amplitude of the Alfvén eigenmodes is at steady levels δB

m/n
/B ∼ 2 × 10−3 and the beam ion losses take place continuously. The beam ion pressure profiles are similar among the different dissipation coefficients, and the stored beam energy is higher for higher dissipation coefficients.
The histone deacetylase Hos2 forms an Hsp42-dependent cytoplasmic granule in quiescent yeast cells
Authors: Liu I-Chun , Chiu Sheng-Wen , Lee Hsin-Yi , Leu Jun-Yi
Published: February 2012

One of many physiological adjustments in quiescent cells is spatial regulation of specific proteins and RNA important for the entry to or exit from the stationary phase. By examining the localization of epigenetic-related proteins in Saccharomyces cerevisiae, we observed the formation of a reversible cytosolic “stationary-phase granule” (SPG) by Hos2, a nuclear histone deacetylase. In the stationary phase, hos2 mutants display reduced viability. Additionally, they exhibit a significant delay when recovering from stationary phase. Hos2 SPGs also contained Hst2, a Sir2 homologue, and several stress-related proteins, including Set3, Yca1, Hsp26, Hsp42, and some known components of stress granules. However, Hos2 SPG formation does not depend on the formation of stress granules or processing bodies. The absence or presence of glucose is sufficient to trigger assembly or disassembly of Hos2 SPGs. Among the identified components of Hos2 SPGs, Hsp42 is the first and last member observed in the Hos2 SPG assembly and disassembly processes. Hsp42 is also vital for the relocalization of the other components to Hos2 SPGs, suggesting that Hsp42 plays a central role in spatial regulation of proteins in quiescent cells.
A reassessment of trends in the North Sea Large Fish Indicator and a re-evaluation of earlier conclusions
Authors: Greenstreet Simon P. R. , Rogers Stuart I. , Rice Jake C. , Piet Gerjan J. , Guirey Emma J. , Fraser Helen M. , Fryer Rob J.
Published: February 2012

Greenstreet, S. P. R., Rogers, S. I., Rice, J. C., Piet, G. J., Guirey, E. J., Fraser, H. M., and Fryer, R. J. 2012. A reassessment of trends in the North Sea Large Fish Indicator and a re-evaluation of earlier conclusions. – ICES Journal of Marine Science, 69: 343–345. Previous analysis of the Large Fish Indicator, the basis for the North Sea “fish communities” EcoQO, suggested a strong recovery between 2001 and 2008. Discovery of a mistake in this earlier analysis now suggests that this recovery is not as strong as first thought, but reanalysis of the corrected data still supports the majority of conclusions drawn in the original paper.
Do Norway pout (Trisopterus esmarkii) die from spawning stress? Mortality of Norway pout in relation to growth, sexual maturity, and density in the North Sea, Skagerrak, and Kattegat
Authors: Nielsen J. Rasmus , Lambert Gwladys , Bastardie Francois , Sparholt Henrik , Vinther Morten
Published: February 2012

Nielsen, J. R., Lambert, G., Bastardie, F., Sparholt, H., and Vinther, M. 2012. Do Norway pout (Trisopterus esmarkii) die from spawning stress? Mortality of Norway pout in relation to growth, sexual maturity, and density in the North Sea, Skagerrak, and Kattegat. – ICES Journal of Marine Science, 69: 197–207. The mortality patterns of Norway pout (NP) are not well understood. It has been suggested that NP undergo heavy spawning mortality, and this paper summarizes and provides new evidence in support of this hypothesis. The very low–absent fishing activity in recent years provides a unique opportunity to analyse the natural life-history traits of cohorts in the NP stock in the North Sea. Based on the ICES trawl survey abundance indices, cohort mortality is found to significantly increase with age. We argue that this cannot be explained by selectiveness in the fishery, potential size-specific migrations out of the area, higher predation pressure on older individuals, or differences in survey catchability by NP age from before to after spawning and that it is higher in the main spawning areas than outside. We found that natural mortality (M) is significantly correlated with sexual maturity, sex, growth, and intraspecific stock density. All of this is consistent with a greater mortality occurring mainly from the first to the second quarter of the year, i.e. spawning mortality, which is discussed as being a major direct and indirect cause of stock mortality.
An evaluation of benthic community structure in and around the Sackville Spur closed area (Northwest Atlantic) in relation to the protection of vulnerable marine ecosystems
Authors: Barrio Froján Christopher R. S. , MacIsaac Kevin G. , McMillan Andrew K. , del Mar Sacau Cuadrado María , Large Philip A. , Kenny Andrew J. , Kenchington Ellen , de Cárdenas González Enrique
Published: February 2012

Barrio Froján, C. R. S., MacIsaac, K. G., McMillan, A. K., del Mar Sacau Cuadrado, M., Large, P. A., Kenny, A. J., Kenchington, E., and de Cárdenas González,  E. 2012. An evaluation of benthic community structure in and around the Sackville Spur closed area (Northwest Atlantic) in relation to the protection of vulnerable marine ecosystems. – ICES Journal of Marine Science, 69: 213–222. The benthic macrofaunal community structure is investigated within and around a closed area at Sackville Spur in the Northwest Atlantic to ascertain whether continued exclusion of bottom fishing can be justified. This and other similar closed areas have been introduced by the Northwest Atlantic Fisheries Organisation (NAFO) to protect areas of likely occurrence of taxa that are indicative of vulnerable marine ecosystems (VMEs) from the damaging effects of bottom-contact fishing gear. Results reveal subtle yet significant differences in macrofaunal assemblage composition and community structure between inside and outside the closed area, between above and below the 1200-m depth contour (i.e. the historical depth limit of fishing), and between areas where dense sponge spicule mats are either present or absent. Differences were observed in many assemblage metrics; however, the most revealing was the greater abundance, biomass, diversity, and number of VME indicative taxa inside the closed area than outside. Overall community composition is also significantly different between treatments. Depth, sediment temperature, and the proportion of clay within sediments are important in shaping the faunal assemblage. The importance of the effects of fishing is discussed, although it is not possible to ascertain if fishing is the direct cause behind observed differences in the macrofaunal assemblage. A continued closure of the area is recommended, as well as options for streamlining the evaluation process of other closed areas.