bluuebunny/crossref_metadata_2025 huggingface dataset:
Distribution and migrations of cetaceans in the Russian Arctic according to observations from aerial ice reconnaissance
Authors: Belikov Stanislav E , Boltunov Andrei N
Published: July 2014

This paper is based on 748 observations of belugas (Delphinapterus leucas) and 382 observations of baleen whales in the Russian Arctic, the majority of the data provided by aerial reconnaissance of sea ice (ARSI). Although the data are not suitable for the estimation of the number and density of the animals, they represent a multi-year (1958-1995) range of observations to update our knowledge on the seasonal distribution and migrations of the species. Belugas inhabit not only shelf waters but also the zone of the shelf slope and the abyssal zone of the Arctic Ocean, where the animals appear mostly in summer. In winter belugas were observed only in the Barents Sea. In June-August, the frequency of beluga observations was highest in the Laptev Sea, which has previously been believed to have considerably lower numbers of beluga than the Kara and Barents seas. Patterns of seasonal distribution and ice cover suggest the existence of a natural border preventing or reducing population exchange between belugas inhabiting the western and eastern parts of the Russian Arctic. A brief review of available data on distribution of the narwhal (Monodon monoceros) in the Russian Arctic is also given. Two species of baleen whales were frequently seen in the Russian Arctic: the bowhead whale (Balaena mysticetus), and the grey whale (Eschrichtius robustus). The majority of such observations were made in the southeastern part of the East-Siberian Sea and the southern part of the Chukchi Sea. In the Bering Sea baleen whales were usually seen near the Chukotka Peninsula, in Anadyr Bay and southeast of it. Whales were usually seen in ice-free water: observations of whales among rarefied ice and near the ice edge were rare. There were considerable annual and seasonal variations in distribution and migrations of baleen whales in the region, probably caused mainly by the dynamics of ice conditions.
Surveys of belugas and narwhals in the Canadian High Arctic in 1996
Authors: Innes Stuart , Heide-Jørgensen MP , Laake Jeff L , Laidre Kristin L , Cleator Holly J , Richard Pierre , Stewart Robert EA
Published: July 2014

The summer range of belugas (Delphinapterus leucas) and narwhals (Monodon monoceros) in Prince Regent Inlet, Barrow Strait and Peel Sound in the Canadian High Arctic was surveyed from 31 July to 3 August 1996 with a visual aerial survey of offshore areas and photographic aerial surveys of concentration areas. The visual survey estimate based on the number of belugas visible to the observers using systematic line transect methods was 10,347 (cv = 0.28). This included corrections for whales that were missed by the observers, observations without distance measurements and an estimate of 1,949 (cv=0.22) belugas from a photographic survey in southern Peel Sound. Using data from belugas tagged with satellite-linked time-depth recorders, the estimate was adjusted for individuals that were diving during the survey which resulted in an estimate of 18,930 belugas (cv = 0.28). Finally, counts of belugas in estuaries, corrected for estuarine surface time, were added to provide a complete estimate of 21,213 belugas (95% CI 10,985 to 32,619). The estimated number of narwhals corrected for sightings that were missed by observers was 16,364 (cv = 0.24). Adjusting this for sightings without distance information and correcting for whales that were submerged produced an estimate of 45,358 narwhals (95% CI 23,397 to 87,932).
Status of the belugas of the St Lawrence estuary, Canada
Authors: Kingsley Michael CS
Published: July 2014

A population of belugas (Delphinapterus leucas) inhabiting the estuary of the St Lawrence river in Quebec, Canada, was depleted by unregulated hunting, not closed until 1979. Surveys in 1977 showed only a few hundred in the population. Surveys since then have produced increasing estimates of population indices. An estimate of the population, fully corrected for diving animals, was 1,238 (SE 119) in September 1997. The population was estimated to have increased from 1988 through 1997 by 31.4 belugas/yr (SE 13.1). Observations of population age structure, as well as data on age at death obtained from beach-cast carcasses, do not indicate serious problems at the population level, although there are indications that mortality of the oldest animals may be elevated. Few animals appear to live much over 30 years. From examination of beach-cast carcasses, it appears that most deaths are due to old age and disease; hunting is illegal, ship strikes and entrapments in fishing gear are rare, ice entrapments and predation are unknown. Among beach-cast carcasses recovered and necropsied, about 23% of the adults have malignant cancers, while most of the juveniles have pneumonia; other pathological conditions are diverse. No factors are known to be limiting numbers of this population. Habitat quality factors, including persistent contaminants, boat traffic and harassment, may affect the population’s rate of increase, but these effects have not been quantitatively evaluated. Comprehensive legislation exists with powers to protect the population and the environment of which it is a component, but application and enforcement of the laws is not without problems.
Patterns of abundance and maturity among three species of parasitic nematodes (Pseudoterranova decipiens, Contracaecum osculatum, Anisakis simplex) co-existing in Sable Island grey seals (Halichoerus grypus)
Authors: Fowler G Mark , Stobo Wayne T
Published: July 2014

The abundance and maturity of three species of anisakine nematode (Pseudoterranova decipiens, Contracaecum osculatum, Anisakis simplex) that co-occurred in the stomachs of Sable Island grey seals were examined in relation to seal growth and seasonal considerations. Sealworm (P. decipiens), the predominant nematode in these seals, typically reached numbers of 400 to 2000 worms per stomach. C. osculatum and A. simplex were usually found in much smaller numbers of 40 to 100 and 20 to 60 worms, respectively, per stomach. All three species initially increased in abundance as the seals grew, but after most of a seals’ growth had been attained P. decipiens abundance continued to increase with age, A. simplex numbers either continued to increase or were simply maintained, while C. osculatum abundance declined. Numbers of both P. decipiens and A. simplex declined during winter breeding/pupping and summer moulting fasts or partial fasts, and rose during the regular feeding periods between the fasts. Conversely, numbers of C. osculatum rose during the breeding period, and also during the moulting period in younger seals. We believe this could be attributed to some degree of feeding on prey species in the immediate vicinity of Sable Island that were not preferred during focused feeding periods, and that the inclination to feed during fasting periods decreased as seals grew. An inverse relationship between worm abundance and worm maturity, attributable to the seasonal changes in rates of ingestion of immature worms, was more pronounced for C. osculatum than P. decipiens. C. osculatum was usually represented by much higher proportions of mature worms than P. decipiens. This could be entirely related to the longer periods of time dedicated to feeding than spent breeding or moulting, but higher mortality rates of immature C. osculatum or greater longevity of mature C. osculatum could also have occurred. A. simplex, generally associated with cetacean species as final hosts, rarely matured in grey seals. We have doubts that the grey seal could be considered a final host for A. simplex.
Food consumption estimates of Barents Sea harp seals
Authors: Nilssen Kjell T , Pedersen Ole-Petter , Folkow Lars P , Haug Tore
Published: July 2014

The consumption of various prey species, required by the Barents Sea harp seal (Phoca groenlandica) stock in order to cover their energy demands, has been estimated by combining data on the energy density of prey species and on seasonal variations in the energy expenditure and body condition of the seals. Data on diet composition and body condition were collected in the period 1990-1996 by sampling harp seals during different seasons, in various areas of the Barents Sea. All diet composition data were based on reconstructed prey biomass, and adjustments were made for differences in digestibility of crustaceans and fish. The number of seals representing different age and sex groups were calculated for the entire population, and the monthly food requirements were estimated. In 1998, the total Barents Sea harp seal stock was estimated to comprise 2.22 million seals based on a mean production of 301,000 pups. After adjustments for a pup mortality of 30% its total annual food consumption was estimated to be in the range of 3.35-5.05 million tonnes (depending on choice of input parameters). Assuming that there are seasonal changes in basal metabolic rate associated withchanges in body mass, and that the field metabolic rate of the seals corresponded to two times their predicted basal metabolic rate, the annual food consumption of the Barents Sea harp seal stock was estimated. If capelin (Mallolus villosus) was assumed to be abundant, the annual total consumption was estimated to be 3.35 million tonnes, of which 1,223,800 tonnes were crustaceans, 807,800 tonneswere capelin, 605,300 tonnes were polar cod (Boreogadus saida), 212,400 tonnes were herring (Clupea harengus), 100,500 tonnes were cod (Gadus morhua) and 404,200 tonnes were "other fish". A very low capelin stock in the Barents Sea (as it was in the period 1993-1996) led to switches in seal diet composition, with increased consumption of polar cod (from ca. 16%-18 % to ca. 23%-25 % oftotal consumption), other gadoids (dominated by cod, but also including haddock (Melanogrammus aeglefinus) and saithe (Pollachius virens)), herring, and "other fish". Using the same set of assumptions as in the previous estimate, the total consumption would have been 3.47 million tonnes, divided between various prey species as follows (in tonnes): polar cod 876,000, codfish (cod, saithe and haddock) 359,700, "other fish" 618,800, herring 392,500, and crustaceans 1,204,200. Overall, the largest quantities of food were estimated to be consumed in the period June-September.In 1999, the total Barents Sea harp seal stock size was estimated to be 2.18 (95% CI, 1.79 to 2.58) million animals, which would give an annual food consumption in the range of 2,69 - 3.96 million tonnes (based on upper and lower 95% confidence limits and adjusted for a pup mortality rate of 0.3) if capelin is assumed to be abundant.
Direct and indirect effects of minke whale abundance on cod and herring fisheries: A scenario experiment for the Greater Barents Sea
Authors: Schweder Tore , Hagen Gro S , Hatlebakk Einar
Published: July 2014

To study the pattern of interaction between minke whale (Balaenoptera acutorostrata) abundance and the main fisheries in the Greater Barents Sea, a simulation experiment was carried out. The population model involves 4 species interconnected in a food web: cod (Gadus morhua), capelin (Mallotus villosus), herring (Clupea harengus) and minke whales. Minke whales are preying on cod, capelin andherring; cod are preying on (young) cod, capelin and herring; herring in the Barents Sea are preying on capelin; while capelin is a bottom prey in the model. The consumption function for minke whales is non-linear in available prey abundance, and is estimated from stomach content data and prey abundance data. The model is dynamic, with a time step of one month, and there are two areas: the BarentsSea and the Norwegian Sea. Minke whale abundances are kept on fixed levels, while recruitment in fish is stochastic.Cod and herring fisheries are managed by quotas targeting fixed fishing mortalities, while capelin is managed with a view to allow the cod to have enough food and leaving a sufficient spawning stock of capelin. The model is simulated over a period of 100 years for a number of fixed levels of minke whaleabundance, and simulated catches of cod, herring and capelin are recorded.The experiment showed interactions between whale abundance and fish catches to be mainly linear. For cod catches, both the direct effect of whales consuming cod, and the indirect effect due to whales competing with cod for food and otherwise altering the ecosystem, are linear and of equal importance. The net effect on the herring fishery is of the same magnitude as the net effect on the cod fishery, witheach extra whale reducing the catches of both species by some 5 tonnes. These conclusions are conditional on the model and its parameterisation.
Global MHD modeling of ionospheric convection and field‐aligned currents associated with IMF By triggered theta auroras
Authors: Watanabe Masakazu , Sakito Shintaro , Tanaka Takashi , Shinagawa Hiroyuki , Murata Ken T.
Published: July 2014

Using numerical magnetohydrodynamic simulations, we investigate the evolution of ionospheric convection and field‐aligned currents (FACs) when θ auroras are formed in response to interplanetary magnetic field (IMF) By transitions. When the polarity of IMF By switches abruptly during northward IMF periods, the crossbar of the θ aurora is isolated from the flankside auroral oval and drifts into the polar cap. This drift motion is involved in a large round cell associated with new IMF By, with sunward convection residing only on the dayside tip of the crossbar. There exists an IMF By‐controlled large‐scale FAC system on the crossbar. When the θ aurora is drifting duskward (dawnward), the FACs are located on the dawnside (duskside) boundary of the crossbar adjacent to the “new” lobe. In contrast, the magnetospheric source region of the crossbar FAC system is located on the duskside (dawnside) boundary of the protruded plasma sheet adjacent to the “old” lobe. In the source region, plasma thermal pressure feeds the electromagnetic energy of FACs, and these processes can be interpreted as coupling of slow mode and Alfvén mode disturbances. In the ionosphere, the crossbar‐associated FACs close with part of the region 1 currents associated with the new crescent cell. The magnetospheric source of that part of the region 1 FACs is located on the plasma sheet boundary and the magnetopause both adjacent to the new lobe. Dynamo processes in the old‐lobe side and the new‐lobe side work together to drive the ionospheric drift motion of the crossbar.
Interhemispheric field‐aligned currents: Simulation results
Authors: Lyatskaya Sonya , Khazanov George V. , Zesta Eftyhia
Published: July 2014

We present simulation results of the 3‐D magnetosphere‐ionosphere current system including the Region 1 and Region 2 field‐aligned currents, ionospheric currents, and interhemispheric field‐aligned currents flowing between the northern and southern conjugate ionospheres in the case of asymmetry in ionospheric conductivities in two hemispheres. The model shows that the interhemispheric currents can be an important part of the global 3‐D current system in high‐latitude ionosphere, especially during summer‐winter months, when in winter ionosphere they can be comparable and even exceed both Region 1 and Region 2 currents. An important feature of these interhemispheric currents is that they link together processes in two hemispheres, so that the currents observed in one hemisphere can provide us with information about the currents in the opposite hemisphere. Although the interhemispheric currents might play a notable role in the total 3‐D current system, they have not been sufficiently studied yet. The study of the contribution from the interhemispheric currents into the total 3‐D current system allows us to improve understanding and forecasting of geomagnetic, auroral, and ionospheric disturbances in two hemispheres.
Variability of sea‐ice in the northern Weddell Sea during the 20th century
Authors: Murphy E. J. , Clarke A. , Abram N. J. , Turner J.
Published: July 2014

The record of winter fast‐ice in the South Orkney Islands, northern Weddell Sea, Antarctica, is over a century long and provides the longest observational record of sea‐ice variability in the Southern Hemisphere. Here we present analyses of the series of fast‐ice formation and breakout dates from 1903 to 2008. We show that over the satellite era (post‐1979), the timing of both final autumn formation and complete spring breakout of fast‐ice is representative of the regional sea‐ice concentrations (SIC) in the northern Weddell Sea, and associated with atmospheric conditions in the Amundsen Sea region to the west of the Antarctic Peninsula. Variation in the fast‐ice breakout date is influenced by the intensity of the westerly/north‐westerly winds associated with the Southern Annular Mode (SAM). In contrast, the date of ice formation displays correlations with regional oceanic and sea‐ice conditions over the previous 18 months, which indicate a preconditioning during the previous summer and winter, and exhibits variability associated with variation in tropical Pacific sea‐surface temperature (i.e., the El Niño‐Southern Oscillation, ENSO). A reduction in fast‐ice duration at the South Orkney Islands around the 1950s was associated with both later formation and earlier breakout. However, there were marked changes in variability (with periodicities of 3–5, 7–9, and 20 years) in each of the series and in their relationships with ENSO and SAM, indicating the need for caution in interpreting changes in ice conditions based on shorter‐term satellite series.
Physics‐controlled thickness of shear zones caused by viscous heating: Implications for crustal shear localization
Authors: Duretz T. , Schmalholz S. M. , Podladchikov Y. Y. , Yuen D. A.
Published: July 2014

We evaluate the parameters that control the thickness of ductile shear zones that are generated by viscous heating. We employ two‐dimensional thermomechanical numerical models to simulate shear zone development under compression. Results show that the shear zone thickness is essentially independent on the numerical resolution and the initial size of a weak inclusion that triggers shear localization. A simple scaling law is derived which predicts the thickness with six physical parameters: far‐field stress and strain rate, thermal conductivity (both constant and temperature dependent), initial temperature, activation energy, and stress exponent. The scaling law is confirmed by numerical simulations for a wide range of parameters. For crustal deformation conditions typical temperature increase ranges between 50°C and 200°C, and the predicted thickness is between 1 km and 7 km. These thicknesses agree with natural crustal and lithospheric shear zones suggesting that shear heating is a process controlling crustal shear zone formation.
The scale of the magnetotail reconnecting current sheet in the presence of O+
Authors: Liu Y. H. , Kistler L. M. , Mouikis C. G. , Roytershteyn V. , Karimabadi H.
Published: July 2014

The reconnection current layer thickness is expected to scale with either the ion inertial length or the ion gyroradius. Both of these quantities scale with the mass of the ions present. During geomagnetically disturbed times, the reconnection layer in the magnetotail can contain a significant amount of O+. Using Cluster multi‐spacecraft measurements, we have studied nine reconnection events in the magnetotail plasmasheet, to determine whether the reconnecting current sheet thickness scales with the ion gyroradius or the ion inertial length, and whether the amount of O+ in the plasma sheet has an effect on the current layer thickness. We find that the thickness is equal to the H+ gyroradius, even when the plasma sheet has a high O+ content. This result is in contrast to Hall MHD expectations and likely results from the multiscale nature of the current sheet.
Nonlinear evolution of ion acoustic solitary waves in space plasmas: Fluid and particle‐in‐cell simulations
Authors: Kakad Bharati , Kakad Amar , Omura Yoshiharu
Published: July 2014

Spacecraft observations revealed the presence of electrostatic solitary waves (ESWs) in various regions of the Earth's magnetosphere. Over the years, many researchers have attempted to model these observations in terms of electron/ion acoustic solitary waves by using nonlinear fluid theory/simulations. The ESW structures predicted by fluid models can be inadequate due to its inability in handling kinetic effects. To provide clear view on the application of the fluid and kinetic treatments in modeling the ESWs, we perform both fluid and particle‐in‐cell (PIC) simulations of ion acoustic solitary waves (IASWs) and estimate the quantitative differences in their characteristics like speed, amplitude, and width. We find that the number of trapped electrons in the wave potential is higher for the IASW, which are generated by large‐amplitude initial density perturbation (IDP). The present fluid and PIC simulation results are in close agreement for small amplitude IDPs, whereas for large IDPs they show discrepancy in the amplitude, width, and speed of the IASW, which is attributed to negligence of kinetic effects in the former approach. The speed of IASW in the fluid simulations increases with the increase of IASW amplitude, while the reverse tendency is seen in the PIC simulation. The present study suggests that the fluid treatment is appropriate when the magnitude of phase velocity of IASW is less than the ion acoustic (IA) speed obtained from their linear dispersion relation, whereas when it exceeds IA speed, it is necessary to include the kinetic effects in the model.
Aspect angle dependence of naturally enhanced ion acoustic lines
Authors: Akbari H. , Semeter J. L.
Published: July 2014

The magnetic aspect angle dependence of naturally enhanced ion acoustic lines (NEIALs) is investigated using two multibeam experiments with the 450 MHz electronically steerable Poker Flat Incoherent Scatter Radar. In each experiment, dynamics in the accompanying auroral activity suggest that the source of free energy for the instability is equally present, in a statistical sense, in a wide portion of sky. Yet strong variations in backscattered power are observed when radar beam direction is altered by only 1°. In our observations, the strongest scattered power appears in the magnetic‐zenith direction and weakens with increasing angle between the radar beam and the magnetic lines of force. NEIALs occurring above the F region peak are observed to disappear almost completely at aspect angles as small as 2°. The results are somewhat surprising since previous experiments have detected NEIALs at aspect angles up to 15°. It is shown that during dynamic geophysical conditions, such as the substorm intervals studied in this report, more than one of the generation mechanisms proposed to explain NEIALs may be operating simultaneously. The different mechanisms result in different spectral morphologies and different degrees of sensitivity to the magnetic aspect angle.
Nonadiabatic heating in magnetic reconnection
Authors: Ma Xuanye , Otto Antonius
Published: July 2014

Plasma transport process as a fundamental problem in magnetospheric physics is often associated with strong nonadiabatic heating. At the magnetopause, observations show an increase of specific entropy (i.e., S = p/ργ) by 2 orders of magnitude from the magnetosheath into the magnetosphere. In the near‐Earth magnetotail, particle injection requires strongly entropy depleted plasma bubbles, and their evolution can be strongly modified in the presence of nonadiabatic heating. In this study, one of the critical plasma transport mechanisms, magnetic reconnection, is investigated as a nonadiabatic process in the framework of MHD. It is important to examine whether magnetic reconnection can provide sufficient nonadiabatic heating to explain the observed plasma properties and to identify plasma conditions that allow such strong nonadiabatic heating. We demonstrate that the entropy can indeed strongly increase associated with magnetic reconnection provided that the plasma beta (i.e., the ratio of thermal to magnetic energy density) is low in the inflow region of reconnection.
Testing pulse density distribution for terrestrial gamma ray flashes
Authors: Abukhaled Marwan , Allen Edward , Guessoum Nidhal
Published: July 2014

Maximum likelihood fits for the time profiles of 51 terrestrial gamma ray flashes (from Compton Gamma Ray Observatory/Burst and Transient Source Experiment and Fermi Gamma‐Ray Space Telescope/Gamma‐Ray Burst Monitor) were calculated for five proposed probability densities. A lognormal distribution, which had been used by other researchers, was compared with piecewise Gaussian, piecewise exponential, inverse Gaussian, and Ornstein‐Uhlenbeck probability density functions. The piecewise Gaussian and piecewise exponential distributions are justified physically through assuming exponential growth and decay of the electron avalanches which result in the gamma ray bursts and are therefore highly relevant in this context. However, identifying the electron avalanche phenomenon as a form of stochastic exit time process, the inverse Gaussian and Ornstein‐Uhlenbeck are reasonable alternatives. Results of the maximum likelihood calculations indicate that the five probability densities fit the gamma ray pulse data equally well. By this comparison, our aim is to indicate to terrestrial gamma ray flash researchers these other at least equally valid distribution functions, which may give insights into the physical processes that the electrons (and the positrons) undergo in the gamma ray flashes.
First U.S.‐China joint ground‐based Fabry‐Perot interferometer observations of longitudinal variations in the thermospheric winds
Authors: Wu Qian , Yuan Wei , Xu Jiyao , Huang Cong , Zhang Xiaoxin , Wang Jing‐song , Li Tao
Published: July 2014

For the first time, three Fabry‐Perot interferometers from the U.S. (Boulder, 40°N, 105°W, 49°N magnetic latitude (MLAT)) and China (Xinglong: 40°N,115°E, 34°N, MLAT; Kelan: 39°N, 112°E, 33°N MLAT) were used to examine the longitudinal variations in the thermospheric winds due to the geomagnetic latitude differences between the American and Asian sectors. During a case of quiet geomagnetic condition, the meridional winds were very similar at the U.S. and Chinese stations. The meridional winds at Boulder reached most equatorward winds after midnight, whereas in China, the largest equatorward winds were found near midnight. The Boulder zonal winds turned westward earlier in the morning hours and had larger diurnal variations because of its higher magnetic latitude. During the case of low geomagnetic activity (Kp~2), the meridional winds were still similar in the U.S. and in China. Boulder zonal winds had much larger diurnal variation compared to the quiet condition (Kp~1). Thermosphere‐ionosphere‐electrodynamics general circulation model simulations show a very good agreement with observation for the meridional winds. The simulated zonal winds exhibit noticeable differences with observations, but the general tendencies in longitudinal variations with a larger diurnal variation near the auroral oval are correct. Simulations showed that the ion drift is not directly responsible for the longitudinal variations in the winds. The pressure gradient had more direct effect on the longitudinal changes in the winds. The simulation results also showed larger diurnal variations at higher geomagnetic latitudes due to the auroral oval heating. Nonmigrating tides were not observed in the two cases in October 2012.
The influence of IMF clock angle timescales on the morphology of ionospheric convection
Authors: Grocott A. , Milan S. E.
Published: July 2014

We exploit a database of high‐latitude ionospheric electric potential patterns, derived from radar observations of plasma convection in the Northern Hemisphere from the years 2000–2006, to investigate the timescales of interplanetary magnetic field (IMF) control of ionospheric convection and associated magnetospheric dynamics. We parameterize the convection observations by IMF clock angle, θ (the angle between geocentric solar magnetic (GSM) north and the projection of the IMF vector onto the GSM Y‐Z plane), and by an IMF timescale, τB (the length of time that a similar clock angle has been maintained prior to the convection observations being made). We find that the nature of the ionospheric convection changes with IMF clock angle, as expected from previous time‐averaged studies, and that for τB∼30 min, the convection patterns closely resemble their time‐averaged counterparts. However, as τB increases we find that the convection evolves away from the time‐averaged patterns to reveal modified characteristic flow features. We discuss these findings in terms of solar wind‐magnetosphere‐ionosphere coupling and consider their implications for understanding the time‐dependent nature of magnetospheric dynamics.
Experimental characterization of broadband electrostatic noise due to plasma compression
Authors: DuBois Ami M. , Thomas Edward , Amatucci William E. , Ganguli Gurudas
Published: July 2014

For a wide variety of laboratory and space plasma environments, theoretical predictions state that plasmas are unstable to inhomogeneous flows over a very broad frequency range. Such sheared flows are generated in the Earth's magnetosphere and intensify during active periods. Specifically, for a velocity shear oriented perpendicular to a uniform background magnetic field, the shear scale length (LE) compared to the ion gyroradius (ρi) determines the character of the shear‐driven instability that may prevail. An interpenetrating plasma configuration is used to create a transverse velocity shear profile in a magnetized plasma column, a condition similar to that found in the natural boundary layers. The continuous variation of ρi/LE and the associated transition of the instability regimes driven by the shear flow mechanism are demonstrated in a single laboratory experiment. Broadband wave emission correlated to increasing/decreasing stress (i.e., ρi/LE), a characteristic signature of a boundary layer crossing, is found under controlled and repeatable conditions. This result holds out the promise for understanding the cause and effect of the in situ observation of broadband electrostatic noise.
Spontaneous Assembly of Extremely Long, Horizontally‐Aligned, Conductive Gold Micro‐Wires in a Langmuir Monolayer Template
Authors: Jiang Hao , Vinod T. P. , Jelinek Raz
Published: July 2014

“Bottom‐up” technologies are based upon the premise that organized systems – from the nano‐scale up to the macro‐scale – can be assembled spontaneously from basic building blocks in solution. We demonstrate a simple strategy for the generation of extremely long (up to several centi­meters), horizontally‐aligned gold micro‐wires, produced through a surfactant monolayer template deposited from gold thiocyanate [Au(SCN)4−] aqueous solution. Specifically, we show that the surfactant, octyl‐maleimide (OM), spontaneously forms oriented micro‐wires at the air/water interface, which constitute a template for deposition of metallic gold through binding and crystallization of the soluble gold complex. The Au micro‐wires can be subsequently transferred onto solid substrates, and following plasma treatment and gold enhancement exhibit excellent conductivity even at electrode spacings of several centimeters. Importantly, the micro‐wire alignment determines the direction of electrical current, demonstrating that long‐range ordering of the micro‐wires can be accomplished, significantly affecting the physical properties of the system. The new approach is simple, robust, and can be readily exploited for bottom‐up fabrication of micro‐wire assemblies and transparent conductive electrodes.
Genetic deletion of the GATA1‐regulated protein α‐synuclein reduces oxidative stress and nitric oxide synthase levels in mature erythrocytes
Authors: Renella Raffaele , Schlehe Julia S. , Selkoe Dennis J. , Williams David A. , LaVoie Matthew J.
Published: July 2014

α‐Synuclein is highly expressed in neural tissue and during erythropoiesis, where the key erythroid regulator GATA1 has been found to modulate its expression. While specific α‐synuclein (SNCA) mutations are known to cause autosomal dominant familial Parkinson's disease, its wild‐type function remains under debate. To investigate the role of α‐synuclein in murine hematopoiesis and erythropoiesis, we utilized Snca knock‐out mice and analyzed erythroid compartments for maturation defects, in vivo erythrocyte survival, and erythrocyte‐based reactive oxygen species (ROS) and nitric oxide synthase (NOS) levels. Our findings show that while bone marrow and spleen erythropoiesis and peripheral blood erythrocyte survival in Snca−/− mice was comparable to controls, the levels of ROS and of NOS‐2 were significantly decreased in mature erythrocytes in these animals. These results indicate a role for α‐synuclein in regulating oxidative stress in erythrocytes in vivo and could open new avenues for the investigation of its function in non‐neural tissue. Am. J. Hematol. 89:974–977, 2014. © 2014 Wiley Periodicals, Inc.
Rituximab–cyclophosphamide‐dexamethasone is highly effective in patients with monoclonal Ig deposit‐related glomerulopathy and indolent non‐Hodgkin lymphomas
Authors: Perry Marielle , Delarche Antoine , Ribes David , Vergez François , Guilbeau‐Frugier Céline , Laurent Camille , Huart Antoine , Tavitian Suzanne , El Hachem Hélène , Oberic Lucie , Chauveau Dominique , Michallet Anne‐Sophie , Ysebaert Loïc , Faguer Stanislas
Published: July 2014

Indolent non‐hodgkin lymphomas (iNHL) are a rare cause of monoclonal immunoglobulin deposits‐related glomerulopathy (mIgGN). In patients with iNHL‐related mIgGN, whether treatment should include either single or a combination of drug(s) to target the malignant clone and renal inflammation remains elusive. In this retrospective study, we report a cohort of 14 patients with iNHL‐related mIgGN (cryoglobulinemic glomerulonephritis [n = 5], membranous nephropathy [n = 3], membranoproliferative glomerulonephritis [n = 3], AL or AL/AH amyloidosis [n = 2], and Light Chain Deposits Disease [n = 1]) and who received a treatment combining rituximab, cyclophosphamide, and dexamethasone (RCD). After a mean follow‐up of 18 ± 4 months, nine patients (63%) had complete haematological response. Renal response was observed in 12 of the 14 patients (86%; complete response: n = 9; partial: n = 3). Estimated glomerular filtration rate increased from 47 ± 7 to 63 ± 8 mL/min/1.73 m2, and proteinuria decreased from 6.5 ± 0.7 to 1.4 ± 0.8 g/24 hr at one year. Following hematological relapse, renal relapse occurred in two patients suggesting sustained clonal eradication offers the best renal protection. Tolerance of RCD was good and the most frequent adverse event was pneumonia (3/14, 21%). RCD is a promising regimen for patients with iNHL and mIgGN, irrespective of glomerular pathologic pattern. Whether steroids can be avoided or minimized remains to be addressed. Am. J. Hematol. 89:969–973, 2014. © 2014 Wiley Periodicals, Inc.
Body symmetry and physical strength in human males
Authors: Fink Bernhard , Weege Bettina , Manning John T. , Trivers Robert
Published: July 2014

Objectives

Body symmetry and physical strength in males have been related to aspects of mate “quality”—women seem to prefer men who display both “good genes” (as indexed by high symmetry/developmental health) and fighting ability (as indexed by physical strength). Here we show that fluctuating asymmetry (FA) of the body and physical strength are negatively correlated.

Methods

Body FA (from 12 paired traits) and handgrip strength (HGS; a measure of muscular power and force) were measured in a sample of 69 heterosexual, right‐handed men (18–42 years).

Results

There were positive correlations of body symmetry with HGS after controlling for the effect of body‐mass‐index.

Conclusions

We conclude that in males, body symmetry and physical strength are correlated such that symmetric individuals tend to develop higher strength, which may contribute to their success in inter‐ and intra‐sexual selection. Am. J. Hum. Biol. 26:697–700, 2014. © 2014 Wiley Periodicals, Inc.
The miR‐137 schizophrenia susceptibility variant rs1625579 does not predict variability in brain volume in a sample of schizophrenic patients and healthy individuals
Authors: Rose Emma J. , Morris Derek W. , Fahey Ciara , Cannon Dara , McDonald Colm , Scanlon Cathy , Kelly Sinead , Gill Michael , Corvin Aiden , Donohoe Gary
Published: July 2014

The micro RNA 137 (miR‐137) variant rs1625579 has been identified as a genome‐wide significant risk variant for schizophrenia. miR‐137 has an established role in neurodevelopment and may mediate cognitive dysfunction in schizophrenia. This role of miR‐137 may be related to changes in brain morphology for risk‐related genotypes; however this has not yet been delineated. Here we considered whether rs1625579 genotype was predictive of indices of brain structure in patients with schizophrenia and healthy controls. Structural magnetic resonance imaging (sMRI) data (i.e. 3T T1‐TFE or 1.5T T1‐MPRAGE) were acquired from 150 healthy controls and 163 schizophrenic patients. Two volumetric analyses that considered the impact of miR‐137/rs1625579 genotype were carried out on sMRI data. In the first analysis, voxel based morphometry was employed to consider genotype‐related variability in local grey and white matter across the entire brain volume. Our secondary analysis utilized the FIRST protocol in FSL to consider the volume of subcortical structures (i.e. bilateral accumbens, amygdala, caudate, hippocampus, pallidum, putamen and thalamus). Several brain regions in both analyses demonstrated the expected main effect of participant group (i.e. schizophrenics < controls), yet there were no regions where we observed an impact of rs1635579 genotype on brain volume. Our analyses suggest that the mechanism by which miR‐137 confers risk for schizophrenia and impacts upon cognitive function may not be mediated by changes in local brain volume. However, it remains to be determined whether or not alternative measures of brain structure are related to these functions of miR‐137. © 2014 Wiley Periodicals, Inc.
Polygenic scores associated with educational attainment in adults predict educational achievement and ADHD symptoms in children
Authors: de Zeeuw Eveline L. , van Beijsterveldt Catharina E.M. , Glasner Tina J. , Bartels M. , Ehli Erik A. , Davies Gareth E. , Hudziak James J. ,   Social Science Genetic Association Consortium, Rietveld Cornelius A. , Groen‐Blokhuis Maria M. , Hottenga Jouke Jan , de Geus Eco J.C. , Boomsma Dorret I.
Published: July 2014

The American Psychiatric Association estimates that 3 to 7 per cent of all school aged children are diagnosed with attention deficit hyperactivity disorder (ADHD). Even after correcting for general cognitive ability, numerous studies report a negative association between ADHD and educational achievement. With polygenic scores we examined whether genetic variants that have a positive influence on educational attainment have a protective effect against ADHD. The effect sizes from a large GWA meta‐analysis of educational attainment in adults were used to calculate polygenic scores in an independent sample of 12‐year‐old children from the Netherlands Twin Register. Linear mixed models showed that the polygenic scores significantly predicted educational achievement, school performance, ADHD symptoms and attention problems in children. These results confirm the genetic overlap between ADHD and educational achievement, indicating that one way to gain insight into genetic variants responsible for variation in ADHD is to include data on educational achievement, which are available at a larger scale. © 2014 Wiley Periodicals, Inc.
Allylzirconiumkomplexe als Reaktionsteilnehmer bei der Zirconocen‐katalysierten α‐Olefinpolymerisation
Authors: Babushkin Dmitrii E. , Panchenko Valentina N. , Brintzinger Hans‐Herbert
Published: July 2014

Bei der Suche nach bisher unerkannten Ruhezuständen von Zirconocenkatalysatoren für die Olefinpolymerisation ergaben kombinierte UV/Vis‐ und NMR‐spektrometrische Methoden, dass kationische, kettentragende Zr‐Allyl‐Komplexe etwa 90 % der Katalysatorkonzentration ausmachen. Andere am Katalyseprozess beteiligte Katalysatorspezies müssen daher aus dem Allylreservoir regeneriert werden, in das sie offenbar häufig zurückfallen.
Cell‐Surface Engineering by a Conjugation‐and‐Release Approach Based on the Formation and Cleavage of Oxime Linkages upon Mild Electrochemical Oxidation and Reduction
Authors: Pulsipher Abigail , Dutta Debjit , Luo Wei , Yousaf Muhammad N.
Published: July 2014

We report a strategy to rewire cell surfaces for the dynamic control of ligand composition on cell membranes and the modulation of cell–cell interactions to generate three‐dimensional (3D) tissue structures applied to stem‐cell differentiation, cell‐surface tailoring, and tissue engineering. We tailored cell surfaces with bioorthogonal chemical groups on the basis of a liposome‐fusion and ‐delivery method to create dynamic, electroactive, and switchable cell‐tissue assemblies through chemistry involving chemoselective conjugation and release. Each step to modify the cell surface: activation, conjugation, release, and regeneration, can be monitored and modulated by noninvasive, label‐free analytical techniques. We demonstrate the utility of this methodology by the conjugation and release of small molecules to and from cell surfaces and by the generation of 3D coculture spheroids and multilayered cell tissues that can be programmed to undergo assembly and disassembly on demand.
Efficient Oxidation and Destabilization of Zn(Cys)4 Zinc Fingers by Singlet Oxygen
Authors: Lebrun Vincent , Tron Arnaud , Scarpantonio Luca , Lebrun Colette , Ravanat Jean‐Luc , Latour Jean‐Marc , McClenaghan Nathan D. , Sénèque Olivier
Published: July 2014

Singlet oxygen (1O2) plays an important role in oxidative stress in all types of organisms, most of them being able to mount a defense against this oxidant. Recently, zinc finger proteins have been proposed to be involved in its cellular detection but the molecular basis of this process still remains unknown. We have studied the reactivity of a Zn(Cys)4 zinc finger with 1O2 by combinations of spectroscopic and analytical techniques, focusing on the products formed and the kinetics of the reaction. We report that the cysteines of this zinc finger are oxidized to sulfinates by 1O2. The reaction of the ZnS4 core with 1O2 is very fast and efficient with almost no physical quenching of 1O2. A drastic (ca. five orders of magnitude) decrease of the Zn2+ binding constant was observed upon oxidation. This suggests that the Zn(Cys)4 zinc finger proteins would release their Zn2+ ion and unfold upon reaction with 1O2 under cellular conditions and that zinc finger sites are likely targets for 1O2.
Enhanced interfacial interaction of epoxy nanocomposites with activated graphene nanosheets
Authors: Deng Hui , Wu Fan , Chen Lei , Xu Zhiwei , Liu Liangsen , Yang Caiyun , Mai Wei , Cheng Bowen
Published: July 2014

The interfacial properties of epoxy nanocomposites reinforced by thermally exfoliated graphene nanosheets (TEG) and activated thermally exfoliated graphene nanosheets (a‐TEG) were compared. The specific surface area (SSA) of a‐TEG with well‐defined micro‐mesopore size distribution was 1000 m2/g, which was much higher that of TEG (550 m2/g). The interfacial interaction between a‐TEG and epoxy was stronger than that of TEG/epoxy owing to their higher SSA and pore size which was proved by dynamic mechanical analysis. As a result, the tensile strength of a‐TEG/epoxy was increased compared with that of TEG/epoxy for all concentrations. In particular, the tensile and flexural strength of a‐TEG/epoxy was increased up to 20 and 50% in comparison to that of TEG/epoxy at 0.05 wt % graphene, respectively. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41164.
Has the World Changed? My Neighbor Might Know: Effects of Social Context on Routine Deviation
Authors: Betsch Tilmann , Lindow Stefanie , Engel Christoph , Ulshöfer Corina , Kleber Janet
Published: July 2014

Routines help individuals save decision effort and protect them from overreacting to volatile environments. Yet routines become dysfunctional if the environment changes fundamentally. Whether the environment has truly changed is often not easy to tell. We experimentally study adaptation to a change in a previously stable environment. Participants have to choose between one of the four decks of cards. Each deck represents a lottery, with a distribution of gains and losses initially unknown to participants. In the learning phase of the experiment, participants acquire the routine to choose the most attractive deck. Unbeknownst to participants, after an interruption, the lotteries represented by the competing decks are changed. We study how participants react to this change. We manipulate whether participants have access to choices by a confederate who most of the time makes the normative choice. In baseline condition, they never do. In the treatments, access is provided either during the learning phase, during the test phase, or during both phases. Participants are most likely to realize that the world has changed if they had access to the confederate's choices in both phases. Copyright © 2014 John Wiley & Sons, Ltd.
Flagellin modulates TIM4 expression in mast cells
Authors: Li Linjing , Mo Lihua , Hao Huijie , Yang Wanhe , Zhou Quanbo , Xue Fumin , Shi Zhaoyang , Liu Zhigang , Yang Ping‐Chang , Feng Baisui
Published: July 2014

T‐helper (Th) 2 polarization functions in a number of immune diseases, but their pathogenesis needs further investigation. Some microbial products or components are strong adjuvants in the creation of mouse models of Th2 polarization. T cell immunoglobulin mucin molecule (TIM) 4 is a facilitator in the initiation of Th2 response. This study looks at the role of one of the microbial products, flagellin (FGN), in the induction of TIM4 expression in mast cells. Bone marrow derived mast cells (BMMC) were generated. Induction of TIM4 in mast cells was assessed in both experiments in vitro and in vivo. The signal transducer and activator of transcription 6 (Stat6) phosphorylation in BMMC were assessed by Western blotting. A coculture model with FGN‐primed BMMC and naïve CD4+ T cells was employed to assess FGN in facilitating the expression of TIM4 in mast cells. After exposure to FGN, TIM4 levels were significantly increased in BMMC and mast cells of the mouse intestine, which was accompanied by increased STAT6 phosphorylation. Culture with FGN‐primed BMMC, naïve CD4+ T cells developed into Th2 cells by a TIM4‐dependent manner. We conclude that FGN can induce mast cells to express TIM4, which helps initiate Th2 polarization.