bluuebunny/crossref_metadata_2025 huggingface dataset:
A statistical study of energy release and transport midway between the magnetic reconnection and initial dipolarization regions in the near‐Earth magnetotail associated with substorm expansion onsets
Authors: Miyashita Y. , Machida S. , Nosé M. , Liou K. , Saito Y. , Paterson W. R.
Published: October 2012

Our previous study showed that the energy release associated with substorm expansion onsets is the most significant midway between the magnetic reconnection and initial dipolarization regions (−12 > X > −18 REin the premidnight sector) in the magnetotail. In the present paper, we have statistically studied the substorm‐associated energy balance and transport in the magnetotail, focusing on the midway region as well as the near‐Earth initial dipolarization region (X > ∼−12 RE). We find that a large amount of energy is released in the midway region, associated with onsets, but only a part of this energy is transported to the near‐Earth initial dipolarization region mainly in the form of the thermal flux and the wave Poynting flux. It is possible that the energy carried by fast earthward flows and waves from the reconnection region is not sufficient for the thermal energy increase and the outward transported energy in the initial dipolarization region, although the magnetic flux may be sufficiently carried. A considerably large amount of the magnetic energy comes from the lobes in the form of the Poynting flux also in the initial dipolarization region.
Direct penetration of the interplanetary electric field to low geomagnetic latitudes and its effect on magnetotelluric sounding
Authors: Brändlein Dirk , Lühr Hermann , Ritter Oliver
Published: October 2012

Long‐term monitoring of geoelectromagnetic fields, recorded with a network of nine stations covering an area of approximately 25,000 km2at low geomagnetic latitudes in northern Chile, reveals systematic and seasonally modulated variations of geomagnetic field properties. The observed seasonal variation affects almost exclusively the east‐west magnetic field component for periods between 100 and 3000 s. The ground‐based measurements of magnetic and electric fields show statistically significant coherences with the interplanetary electric field derived from solar wind and interplanetary magnetic field data of the Advanced Composition Explorer satellite. The interplanetary electric field (IEF) penetrates the polar ionosphere from where it propagates toward equatorial latitudes by waveguide transmission, with ionosphere and solid Earth acting as conducting boundaries. Signal coherence between IEF and ground data peaks at periods of approximately 90 min and up to the four harmonics. Coherence values reach 0.4 at these periods and depend on the electromagnetic field component. They vary with season and local time. Transfer functions computed between IEF and ground‐based electric and magnetic fields show local maxima at similar periods (90 min and harmonics). The coupling between the east‐west magnetic field component and the IEF shows significant seasonal variability, much larger than the other electromagnetic field components. We conclude that the IEF drives primarily a global circuit of Pedersen currents in the ionosphere. Resulting time‐varying magnetic fields induce electric currents in the ground. Related ground‐based magnetic (primarily north‐south) and electric (primarily east‐west) signals vary coherently at all local times and seasons. Conversely, magnetic signals caused by the IEF‐driven Hall currents depend much on local time and season. We show for the first time that these ionospheric Hall currents cause no induction in the ground, but they generate magnetic signatures that are confined to the waveguide between ionosphere and Earth's surface.
An error estimation method for precipitation and temperature projections for future climates
Authors: Woldemeskel F. M. , Sharma A. , Sivakumar B. , Mehrotra R.
Published: October 2012

Projections of precipitation and temperature from Global Climate Models (GCMs) are generally the basis for assessment of the impact of climate change on water resources. The reliability of such assessments, however, is questionable, since GCM projections are subject to uncertainties arising from inaccuracies in the models, greenhouse gas emission scenarios, and initial conditions (or ensemble runs) used. The purpose of the present study is to quantify these sources of uncertainties in future precipitation and temperature projections from GCMs. To this end, we propose a method to estimate a measure of the associated uncertainty (or error), the square root of error variance (SREV), that varies with space and time as a function of the GCM being assessed. The method is applied to estimate uncertainty in monthly precipitation and temperature outputs from six GCMs for the period 2001–2099. The results indicate that, for both precipitation and temperature, uncertainty due to model structure is the largest source of uncertainty. Scenario uncertainly increases, especially for temperature, in future due to divergence of the three emission scenarios analyzed. It is also found that ensemble run uncertainty is more important in precipitation simulation than in temperature simulation. Estimation of uncertainty in both space and time sheds lights on the spatial and temporal patterns of uncertainties in GCM outputs. The generality of this error estimation method also allows its use for uncertainty estimation in any other output from GCMs, providing an effective platform for risk‐based assessments of any alternate plans or decisions that may be formulated using GCM simulations.
Calving seismicity from iceberg–sea surface interactions
Authors: Bartholomaus T. C. , Larsen C. F. , O'Neel S. , West M. E.
Published: October 2012

Iceberg calving is known to release substantial seismic energy, but little is known about the specific mechanisms that produce calving icequakes. At Yahtse Glacier, a tidewater glacier on the Gulf of Alaska, we draw upon a local network of seismometers and focus on 80 hours of concurrent, direct observation of the terminus to show that calving is the dominant source of seismicity. To elucidate seismogenic mechanisms, we synchronized video and seismograms to reveal that the majority of seismic energy is produced during iceberg interactions with the sea surface. Icequake peak amplitudes coincide with the emergence of high velocity jets of water and ice from the fjord after the complete submergence of falling icebergs below sea level. These icequakes have dominant frequencies between 1 and 3 Hz. Detachment of an iceberg from the terminus produces comparatively weak seismic waves at frequencies between 5 and 20 Hz. Our observations allow us to suggest that the most powerful sources of calving icequakes at Yahtse Glacier include iceberg‐sea surface impact, deceleration under the influence of drag and buoyancy, and cavitation. Numerical simulations of seismogenesis during iceberg‐sea surface interactions support our observational evidence. Our new understanding of iceberg‐sea surface interactions allows us to reattribute the sources of calving seismicity identified in earlier studies and offer guidance for the future use of seismology in monitoring iceberg calving.
Global burned area and biomass burning emissions from small fires
Authors: Randerson J. T. , Chen Y. , van der Werf G. R. , Rogers B. M. , Morton D. C.
Published: October 2012

In several biomes, including croplands, wooded savannas, and tropical forests, many small fires occur each year that are well below the detection limit of the current generation of global burned area products derived from moderate resolution surface reflectance imagery. Although these fires often generate thermal anomalies that can be detected by satellites, their contributions to burned area and carbon fluxes have not been systematically quantified across different regions and continents. Here we developed a preliminary method for combining 1‐km thermal anomalies (active fires) and 500 m burned area observations from the Moderate Resolution Imaging Spectroradiometer (MODIS) to estimate the influence of these fires. In our approach, we calculated the number of active fires inside and outside of 500 m burn scars derived from reflectance data. We estimated small fire burned area by computing the difference normalized burn ratio (dNBR) for these two sets of active fires and then combining these observations with other information. In a final step, we used the Global Fire Emissions Database version 3 (GFED3) biogeochemical model to estimate the impact of these fires on biomass burning emissions. We found that the spatial distribution of active fires and 500 m burned areas were in close agreement in ecosystems that experience large fires, including savannas across southern Africa and Australia and boreal forests in North America and Eurasia. In other areas, however, we observed many active fires outside of burned area perimeters. Fire radiative power was lower for this class of active fires. Small fires substantially increased burned area in several continental‐scale regions, including Equatorial Asia (157%), Central America (143%), and Southeast Asia (90%) during 2001–2010. Globally, accounting for small fires increased total burned area by approximately by 35%, from 345 Mha/yr to 464 Mha/yr. A formal quantification of uncertainties was not possible, but sensitivity analyses of key model parameters caused estimates of global burned area increases from small fires to vary between 24% and 54%. Biomass burning carbon emissions increased by 35% at a global scale when small fires were included in GFED3, from 1.9 Pg C/yr to 2.5 Pg C/yr. The contribution of tropical forest fires to year‐to‐year variability in carbon fluxes increased because small fires amplified emissions from Central America, South America and Southeast Asia—regions where drought stress and burned area varied considerably from year to year in response to El Nino‐Southern Oscillation and other climate modes.
Whistler mode resonance‐cone transmissions at 100 kHz in the OEDIPUS‐C experiment
Authors: Chugunov Y. V. , Fiala V. , Hayosh M. , James H. G.
Published: October 2012

A radio transmitter was operated at one end of the tethered sounding rocket double payload OEDIPUS C, and a synchronized receiver at the other end. Both the transmitter and the receiver were connected to “double‐V” dipoles. On the flight downleg after the tether had been cut, direct bistatic propagation experiments were carried out successfully with the transmitter‐receiver pair. This paper addresses the transmission of 300‐μs pulses at a carrier frequency of 100 kHz between the dipoles over distances of about 1200 m. The waves of interest propagate in the whistler mode close to its resonance cone, where the transmitter is situated in the cone apex. The radiated field under these conditions is computed as well as the resonance response of the receiving antenna, i.e., its effective length. In the whistler mode, the influence of the plasma is important and it results in qualitative changes in the structure of the radiated field and in the value of the receiving antenna effective length as compared to the free space case. Our main concern is the excitation and reception of a pulsed signal when time and space dispersion play important roles in both the delay and spreading of such a signal.
Molecularly modified VP3 (30–121) induces apoptosis in human bladder cancer (EJ) cells but not in normal (3T3) cells
Authors: Yang Junfeng , Wang Jiansong , Zuo Yigang , Zhan Hui
Published: October 2012

The chicken anaemia virus protein 3 (VP3 or apoptin) induces apoptosis specifically in tumour and transformed cells but not in normal cells. This selective apoptosis is ideal for therapeutic purposes. However, VP3, a heterologous protein, is immunogenic in vivo. Such a drawback limits its clinical usage. To diminish its potential immunogenicity, we modified the sequence of VP3. The VP3 genes functional sequence starts at 33 AA (amino acids) from the N‐terminal side, and the first protein structural domain consists of 30 AA. We found that the first domain of VP3 contains no functional sequences. Therefore, this domain was removed to test whether its absence affects apoptosis. Transfection of EGFP (enhance green fluorescent protein)‐modified‐VP3 or HA‐modified‐VP3 in bladder cancer cell lines (EJ) resulted in its expression, successful localization to the nucleus and efficient induction of apoptosis. Expression of EGFP‐modified‐VP3 or HA‐modified‐VP3 had no influence on mouse fibroblast cells (3T3). The modified VP3 (30–121), like the wild‐type VP3, induced EJ cell apoptosis without affecting 3T3 cells. This study increases our understanding of modified VP3 (30–121) as a possible substitute for the wild‐type VP3, which makes VP3 (30–121) an interesting candidate for the development of novel therapeutic strategies.
A full free spectral range tuning of p-i-n doped gallium nitride microdisk cavity
Authors: Niu Nan , Liu Tsung-Li , Aharonovich Igor , Russell Kasey J. , Woolf Alexander , Sadler Thomas C. , El-Ella Haitham A. R. , Kappers Menno J. , Oliver Rachel A. , Hu Evelyn L.
Published: October 2012

Effective, permanent tuning of the whispering gallery modes (WGMs) of p-i-n doped GaN microdisk cavity with embedded InGaN quantum dots over one free spectral range is demonstrated by irradiating the microdisks with a ultraviolet laser (380 nm) in DI water. For incident laser powers between 150 and 960 nW, the tuning rate varies linearly. Etching of the top surface of the cavity is proposed as the driving force for the observed shift in WGMs and is supported by experiments. The tuning for GaN/InGaN microdisk cavities is an important step for deterministically realizing nanophotonic devices for studying cavity quantum electrodynamics.
Transient effects of pump-probe optical response in intersubband transitions of semiconductor quantum wells
Authors: Kosionis Spyridon G. , Terzis Andreas F. , Paspalakis Emmanuel
Published: October 2012

We study theoretically the time evolution of nonlinear optical phenomena of a probe electromagnetic field pulse in intersubband transitions of a semiconductor quantum well structure under the influence of a pump electromagnetic field. More specifically, we take into consideration the effects of electron-electron interactions and consider the interaction of a two-subband system with rectangular electromagnetic fields. The spectral form of the linear absorption, dispersion, and nonlinear optical Kerr effect is described, from the time that the external field is applied up until the dynamics of the system has reached a steady state. In order to describe the dynamics of the system, the effective nonlinear Bloch equations are used, in which renormalized terms for the transition energy and the applied field have been added, due to the effects of electron-electron interactions. These equations are properly combined, and the differential equations of the density matrix elements for the several optical phenomena up to third order are derived. These are solved numerically in the whole time range up to the steady state for a GaAs/AlGaAs quantum well structure. We show that the form of the several optical spectra studied here has a significantly altered evolution over time, according to the value of the frequency of the pump field and of electron sheet density. Even in the case in which the spectral form in the steady state case is almost identical for two different sets of parameters, their evolution can be quite different, according to the precise value of these parameters.
Efficient active actuation to imitate locomotion of gecko's toes using an ionic polymer-metal composite actuator enhanced by carbon nanotubes
Authors: Yu Min , He Qingsong , Yu Dingshan , Zhang Xiaoqing , Ji Aihong , Zhang Hao , Guo Ce , Dai Zhendong
Published: October 2012

Active actuation of the adhesive pads is important for a gecko-robot climbing on walls. We demonstrate the fabrication of an ionic polymer-metal composite (IPMC) actuator enhanced with carbon nanotubes (CNTs) and its use for actively actuating an adhesive array to imitate the locomotion of gecko's toes. The as-fabricated IPMC actuator doped with CNTs exhibits a maximum blocking force of 3.59 gf driven at a low voltage of 3 V. It can be easily controlled by voltage signals to actuate an artificial gecko's toe to attach and detach from a surface. This will allow active, distributed actuation in a gecko robot.
Comparison of two generation-recombination terms in the Poisson-Nernst-Planck model
Authors: Lelidis I. , Barbero G. , Sfarna A.
Published: October 2012

Two phenomenological forms proposed to take into account the generation-recombination phenomenon of ions are investigated. The first form models the phenomenon as a chemical reaction, containing two coefficients describing the dissociation of neutral particles in ions, and the recombination of ions to give neutral particles. The second form is based on the assumption that in thermodynamical equilibrium, a well-defined density of ions is stable. Any deviation from the equilibrium density gives rise to a source term proportional to the deviation, whose phenomenological coefficient plays the role of a life time. The analysis is performed by evaluating the electrical response of an electrolytic cell to an external stimulus for both forms. For simplicity we assume that the electrodes are blocking, that there is only a group of negative and positive ions, and that the negative ions are immobile. For the second form, two cases are considered: (i) the generation-recombination phenomenon is due to an intrinsic mechanism, and (ii) the production of ions is triggered by an external source of energy, as in a solar cell. We show that the predictions of the two models are different at the impedance as well as at the admittance level. In particular, the first model predicts the existence of two plateaux for the real part of the impedance, whereas the second one predicts just one. It follows that impedance spectroscopy measurements could give information on the model valid for the generation-recombination of ions.
Size and polydispersity effect on the magnetization of densely packed magnetic nanoparticles
Authors: Russier Vincent , de Montferrand Caroline , Lalatonne Yoann , Motte Laurence
Published: October 2012

The magnetic properties of densely packed magnetic nanoparticles (MNP) assemblies are investigated from Monte Carlo simulations. The case of iron oxide nanoparticles is considered as a typical example of MNP. The main focus is put on particle size, and size polydispersity influences on the magnetization curve. The particles are modeled as uniformly magnetized spheres isolated one from each other by a non magnetic layer representing the organic coating. A comparison with recent experimental results on γ−Fe2O3 powder samples differing by their size is given.
Electrically driven metal-insulator switching in δ-KxV2O5 nanowires
Authors: Wu Tai-Lung , Stabile Adam A. , Patridge Christopher J. , Banerjee Sarbajit , Sambandamurthy G.
Published: October 2012

Metal-insulator transition (MIT) in δ-KxV2O5 nanowires is studied via tuning temperature, voltage, and current. In the temperature-driven case, a massive drop in resistance over ∼4 orders of magnitude at ∼380 K is reported [C. J. Patridge et al., Nano Lett. 10, 2448 (2010)]. Our observation of electrically driven MIT results from a systematic study in any δ-MxV2O5 system (M is the intercalation ion). In the voltage-driven case, the threshold voltage follows an exponential relation with temperature. In the current-driven case, a negative differential resistance region is observed. These results suggest that δ-KxV2O5 is an interesting oxide system exhibiting strong electrically driven MIT and will hence be useful in several switching applications.
Theoretical study on piezoresponse of ultrathin ferroelectric films
Authors: Lu Xiaoyan , Li Hui , Cao Wenwu
Published: October 2012

Piezoelectric effect is crucial in some nano devices, but it usually decreases with the reduction of film thickness. A comprehensive study of the nonlinear piezoresponse under an applied voltage has been carried out within the framework of the Landau phenomenological theory. For expitaxial heterostructures, polarization exists even below the critical thickness of a few atomic layers due to the large compressive strain provided by the substrate. Piezoelectric coefficient could be very large in the vicinity of the critical thickness due to the appearance of a dielectric susceptibility peak at the phase transition point. Under an applied voltage, the susceptibility peak is reduced and broadened, accompanying a nonlinear piezoresponse even below the critical thickness.
Aqueous interaction site integral-equation theory that exactly takes into account intramolecular correlations
Authors: Chong Song-Ho , Ham Sihyun
Published: October 2012

We report the development of a formally exact integral equation for the three-dimensional hydration structure around molecular solutes of arbitrary complexity. A distinctive feature of our theory—termed aqueous interaction site (AXIS) integral-equation theory—is that it fully takes into account the intramolecular structural correlations of solvent water, which has been missing in the previous integral-equation theories such as the three-dimensional reference interaction site model (3D-RISM) theory. With a simplifying approximation in which the intermolecular bridge function is neglected, an illustrative application of the AXIS theory is made on the equilibrium oxygen and hydrogen distributions of solvent water surrounding a solute water molecule at ambient and supercritical conditions. We demonstrate through a comparison with molecular dynamics simulation results that the inclusion of the exact intramolecular correlations improves upon the 3D-RISM theory in describing the water distribution around molecular solute, in particular near the surface region of the solute molecule, though there still remain quantitative differences from the simulation results. To further improve the quantitative accuracy of the theory, one needs to incorporate the intermolecular bridge function, and a possible formulation for the approximate bridge function is suggested based on the angular decomposition.
Room temperature 1.5 μm light-emitting silicon diode with embedded β-FeSi2 nanocrystallites
Authors: Galkin N. G. , Chusovitin E. A. , Goroshko D. L. , Shevlyagin A. V. , Saranin A. A. , Shamirzaev T. S. , Zhuravlev K. S. , Latyshev A. V.
Published: October 2012

Light-emitting silicon diode structures with embedded β-FeSi2 nanocrystallites have been fabricated using solid phase epitaxy and a combination of reactive deposition and solid phase epitaxy. Electroluminescence (EL) of the structures was studied over various temperatures and current densities under forward and reverse biases. The structures with nanocrystallites formed by the combined method exhibited EL at temperatures below 70 K only, suggesting the presence of a high concentration of defects—non-radiative centers. High-quality defect-free structures with nanocrystallites formed by solid phase epitaxy revealed intensive room temperature EL in energy range 0.76–1.08 eV at current densities as low as 1 A/cm2.
Hole transport in boron delta-doped diamond structures
Authors: Chicot G. , Tran Thi T. N. , Fiori A. , Jomard F. , Gheeraert E. , Bustarret E. , Pernot J.
Published: October 2012

The temperature dependence of the hole sheet density and mobility of four capped delta boron doped [100]-oriented epilayers has been investigated experimentally and theoretically over a large temperature range (6 K<T<500 K). The influence of the parallel conduction through the thick buffer layer overgrown on the diamond substrate was shown not to be negligible near room temperature. This could lead to erroneous estimates of the hole mobility in the delta layer. None of the delta-layers studied showed any quantum confinement enhancement of the mobility, even the one which was thinner than 2 nm.
Enhancement of photocurrent in ultrathin active-layer photodetecting devices with photonic crystals
Authors: Shigeta Hiroaki , Fujita Masayuki , Tanaka Yoshinori , Oskooi Ardavan , Ogawa Hiroyuki , Tsuda Yusuke , Noda Susumu
Published: October 2012

We demonstrate an enhancement of the photoelectric-conversion efficiency of an ultrathin (50 nm) silicon active-layer photodetecting device using a two-dimensional photonic crystal positioned nearby to boost the optical absorption. We show both experimentally and with simulations that the incident-light absorption within the active layer is enhanced by optical-resonance effects at the photonic band edge. We also find that a photonic crystal with deeper holes can lead to an even larger absorption enhancement due to better quality (Q)-factor matching between the photonic band-edge modes and the intrinsic material absorption. The experimentally observed photocurrent of the fabricated photonic-crystal sample is increased by a factor of ∼20 at the photonic band-edge wavelength relative to that of a control sample without the photonic crystal which is attributed to the improved Q matching.
Delays in access to affordable medicines: putting policy into perspective
Authors: Pearce Alison , van Gool Kees , Haywood Philip , Haas Marion
Published: October 2012

Background.
To save costs, the Australian Government recently deferred approval of seven new medicines recommended by the Pharmaceutical Benefits Advisory Committee (PBAC) for up to 7 months.

Objectives.
The aim of this research is to examine the timelines of PBAC applications following approval by the Therapeutic Goods Administration (TGA), allowing the recent Cabinet delays to be considered in the context of the overall medicines approval process.

Methods.
All new chemical entities and products for new indications approved in 2004 by the Australian Drug Evaluation Committee (ADEC) were identified. Outcomes of PBAC meetings from 2004 to 2010 were then searched to identify if and when these products were reviewed by PBAC.

Results.
ADEC recommended 63 eligible products for registration in 2004. Of the 113 submissions made to PBAC for these products, 66 were successful. Only 43% of the products were submitted to PBAC within 2 years, with an average 17-month delay from TGA approval of a product to consideration by the PBAC.

Conclusions.
Cabinet decisions to defer listing of new medicines delays access to new treatments. This occurred in addition to other longer delays, earlier in the approval process for medicines, resulting in a significant impact on the overall timeliness of listing.

What is known about the topic?
There is evidence that the time from registration of new drugs on the TGA to their listing for subsidised availability is increasing. The government’s recent decision to delay the listing of seven new drugs for subsidisation raised concerns about the potential for additional delays to impact the accessibility of new, affordable medicines for patients.

What does this paper add?
This paper examines delays at various stages in the process of approval for pharmaceutical subsidies on the Pharmaceutical Benefits Scheme (PBS), putting the deferral of new medicine listings in the overall context of the approval process. It identifies the potential role of pharmaceutical companies and product sponsors in delaying access to new, affordable medicines early in the approval process.

What are the implications for practitioners?
Delays in the subsidisation of medicines, wherever they occur in the process, not only reduce patient access, but may also lead to pressure in other areas of the health care system to finance such medicines. This makes these results of particular interest to clinician managers, health care managers and policy makers.
‘Haying-off' in wheat is predicted to increase under a future climate in south-eastern Australia
Authors: Nuttall J. G. , O'Leary G. J. , Khimashia N. , Asseng S. , Fitzgerald G. , Norton R.
Published: October 2012

Under a future climate for south-eastern Australia there is the likelihood that the net effect of elevated CO2, (eCO2) lower growing-season rainfall and high temperature will increase haying-off thus limit production of rain-fed wheat crops. We used a modelling approach to assess the impact of an expected future climate on wheat growth across four cropping regions in Victoria. A wheat model, APSIM-Nwheat, was performance tested against three datasets: (i) a field experiment at Wagga Wagga, NSW; (ii) the Australian Grains Free Air Carbon dioxide Enrichment (AGFACE) experiment at Horsham, Victoria; and (iii) a broad-acre wheat crop survey in western Victoria. For down-scaled climate predictions for 2050, average rainfall during October, which coincides with crop flowering, decreased by 32, 29, 26, and 18% for the semiarid regions of the northern Mallee, the southern Mallee, Wimmera, and higher rainfall zone, (HRZ) in the Western District, respectively. Mean annual minimum and maximum temperature over the four regions increased by 1.9 and 2.2°C, respectively. A pair-wise comparison of the yield/anthesis biomass ratio across climate scenarios, used for assessing haying-off response, revealed that there was a 39, 49 and 47% increase in frequency of haying-off for the northern Mallee, southern Mallee and Wimmera, respectively, when crops were sown near the historically optimal time (1 June). This translated to a reduction in yield from 1.6 to 1.4 t/ha (northern Mallee), 2.5 to 2.2 t/ha (southern Mallee) and 3.7 to 3.6 t/ha (Wimmera) under a future climate. Sowing earlier (1 May) reduced the impact of a future climate on haying-off where decreases in yield/anthesis biomass ratio were 24, 28 and 23% for the respective regions. Heavy textured soils exacerbated the impact of a future climate on haying-off within the Wimmera. Within the HRZ of the Western District crops were not water limited during grain filling, so no evidence of haying-off existed where average crop yields increased by 5% under a future climate (6.4–6.7 t/ha). The simulated effect of eCO2 alone (FACE conditions) increased average yields from 18 to 38% for the semiarid regions but not in the HRZ and there was no evidence of haying-off. For a future climate, sowing earlier limited the impact of hotter, drier conditions by reducing pre-anthesis plant growth, grain set and resource depletion and shifted the grain-filling phase earlier, which reduced the impact of future drier conditions in spring. Overall, earlier sowing in a Mediterranean-type environment appears to be an important management strategy for maintaining wheat production in semiarid cropping regions into the future, although this has to be balanced with other agronomic considerations such as frost risk and weed control.
Effects of tail docking and castration on stress responses in lambs and the influence of prenatal glucocorticoid treatment
Authors: Li Shaofu , Nitsos Ilias , Polglase Graeme R. , Newnham John P. , Challis John R. G. , Moss Timothy J. M.
Published: October 2012

It is common practice in Australian agriculture to remove the tails of lambs to prevent infection and to castrate males to prevent behavioural problems and unwanted reproduction. We have studied the pain and stress responses to these interventions by measuring changes in the hypothalamic–pituitary–adrenal (HPA) axis and β-endorphin levels. Further, we have evaluated the effects of prenatal exposure to dexamethasone, which is known to affect the developing HPA axis. In control animals that had received prenatal saline treatment, plasma cortisol and adrenocorticotrophin (ACTH) levels increased after the interventions in both females and males. Plasma β-endorphin levels also increased after the interventions, but the responses were less consistent. Prenatal dexamethasone exposure early in pregnancy (dexamethasone 0.14 mg kg–1 ewe weight injection commenced on day 40 of pregnancy for four consecutive intramuscular injections at 12-hourly intervals) blunted the cortisol response to tail docking in female offspring, but not to combined tail docking and castration in males. It had no effect on ACTH or β-endorphin responses in either sex. These findings describe the stress responses to these common agricultural interventions and suggest that long-term development of the HPA axis in females is altered by prenatal exposure to dexamethasone.
Epistatic interactions between
Tgfb1
and genetic loci,
Tgfbm2
and
Tgfbm3
, determine susceptibility to an asthmatic stimulus
Authors: Freimuth Julia , Clermont Frederic F. , Huang Xiaozhu , DeSapio Angela , Tokuyasu Taku A. , Sheppard Dean , Akhurst Rosemary J.
Published: October 2012

TGFβ activation and signaling have been extensively studied in experimental models of allergen-induced asthma as potential therapeutic targets during chronic or acute phases of the disease. Outcomes of experimental manipulation of TGFβ activity have been variable, in part due to use of different model systems. Using an ovalbumin (OVA)-induced mouse model of asthma, we here show that innate variation within TGFβ1 genetic modifier loci,
Tgfbm2
and
Tgfbm3
, alters disease susceptibility. Specifically,

Tgfbm2
129

and

Tgfbm3
C57

synergize to reverse accentuated airway hyperresponsiveness (AHR) caused by low TGFβ1 levels in

Tgfb1
+/−

mice of the NIH/OlaHsd strain. Moreover, epistatic interaction between

Tgfbm2
129

and

Tgfbm3
C57

uncouples the inflammatory response to ovalbumin from those of airway remodeling and airway hyperresponsiveness, illustrating independent genetic control of these responses. We conclude that differential inheritance of genetic variants of
Tgfbm
genes alters biological responses to reduced TGFβ1 signaling in an experimental asthma model. TGFβ antagonists for treatment of lung diseases might therefore give diverse outcomes, dependent on genetic variation.
Evidence of asymmetric cell division and centrosome inheritance in human neuroblastoma cells
Authors: Izumi Hideki , Kaneko Yasuhiko
Published: October 2012

Asymmetric cell division (ACD) is believed to be a physiological event that occurs during development and tissue homeostasis in a large variety of organisms. ACD produces two unequal daughter cells, one of which resembles a multipotent stem and/or progenitor cell, whereas the other has potential for differentiation. Although recent studies have shown that the balance between self-renewal and differentiation potentials is precisely controlled and that alterations in the balance may lead to tumorigenesis in
Drosophila
neuroblasts, it is largely unknown whether human cancer cells directly show ACD in an evolutionarily conserved manner. Here, we show that the conserved polarity/spindle protein NuMA is preferentially localized to one side of the cell cortex during cell division, generating unequal inheritance of fate-altering molecules in human neuroblastoma cell lines. We also show that the cells with a single copy of
MYCN
showed significantly higher percentages of ACD than those with
MYCN
amplification. Moreover, suppression of MYCN in
MYCN
-amplified cells caused ACD, whereas expression of MYCN in
MYCN
-nonamplified cells enhanced symmetric cell division. Furthermore, we demonstrate that centrosome inheritance follows a definite rule in ACD: The daughter centrosome with younger mother centriole is inherited to the daughter cell with NuMA preferentially localized to the cell cortex, whereas the mother centrosome with the older mother centriole migrates to the other daughter cell. Thus, the mechanisms of cell division of ACD or symmetric cell division and centrosome inheritance are recapitulated in human cancer cells, and these findings may facilitate studies on cancer stem cells.
Acute selective ablation of rat insulin promoter-expressing (RIP
HER
) neurons defines their orexigenic nature
Authors: Rother Eva , Belgardt Bengt F. , Tsaousidou Eva , Hampel Brigitte , Waisman Ari , Myers Martin G. , Brüning Jens C.
Published: October 2012

Rat insulin promoter (RIP)-expressing neurons in the hypothalamus control body weight and energy homeostasis. However, genetic approaches to study the role of these neurons have been limited by the fact that RIP expression is predominantly found in pancreatic β-cells, which impedes selective targeting of neurons. To define the function of hypothalamic RIP-expressing neurons, we set out to acutely and selectively eliminate them via diphtheria toxin-mediated ablation. Therefore, the diphtheria toxin receptor transgene was specifically expressed upon RIP-specific Cre recombination using a RIP-Cre line first described by Herrera (RIP
HER
-Cre) [Herrera PL (2000)
Development
127:2317–2322]. Using proopiomelanocortin–expressing cells located in the arcuate nucleus of the hypothalamus and in the pituitary gland as a model, we established a unique protocol of intracerebroventricular application of diphtheria toxin to efficiently ablate hypothalamic cells with no concomitant effect on pituitary proopiomelanocortin–expressing corticotrophs in the mouse. Using this approach to ablate RIP
HER
neurons in the brain, but not in the pancreas, resulted in decreased food intake and loss of body weight and fat mass. In addition, ablation of RIP
HER
neurons caused increased c-Fos immunoreactivity of neurons in the paraventricular nucleus (PVN) of the hypothalamus. Moreover, transsynaptic tracing of RIP
HER
neurons revealed labeling of neurons located in the PVN and dorsomedial hypothalamic nucleus. Thus, our experiments indicate that RIP
HER
neurons inhibit anorexigenic neurons in the PVN, revealing a basic orexigenic nature of these cells.
Recent changes of the Earth’s core derived from satellite observations of magnetic and gravity fields
Authors: Mandea Mioara , Panet Isabelle , Lesur Vincent , de Viron Olivier , Diament Michel , Le Mouël Jean-Louis
Published: October 2012

To understand the dynamics of the Earth’s fluid, iron-rich outer core, only indirect observations are available. The Earth’s magnetic field, originating mainly within the core, and its temporal variations can be used to infer the fluid motion at the top of the core, on a decadal and subdecadal time-scale. Gravity variations resulting from changes in the mass distribution within the Earth may also occur on the same time-scales. Such variations include the signature of the flow inside the core, though they are largely dominated by the water cycle contributions. Our study is based on 8 y of high-resolution, high-accuracy magnetic and gravity satellite data, provided by the CHAMP and GRACE missions. From the newly derived geomagnetic models we have computed the core magnetic field, its temporal variations, and the core flow evolution. From the GRACE CNES/GRGS series of time variable geoid models, we have obtained interannual gravity models by using specifically designed postprocessing techniques. A correlation analysis between the magnetic and gravity series has demonstrated that the interannual changes in the second time derivative of the core magnetic field under a region from the Atlantic to Indian Ocean coincide in phase with changes in the gravity field. The order of magnitude of these changes and proposed correlation are plausible, compatible with a core origin; however, a complete theoretical model remains to be built. Our new results and their broad geophysical significance could be considered when planning new Earth observation space missions and devising more sophisticated Earth’s interior models.
Construction of a rationally designed antibody platform for sequencing-assisted selection
Authors: Larman H. Benjamin , Jing Xu George , Pavlova Natalya N. , Elledge Stephen J.
Published: October 2012

Antibody discovery platforms have become an important source of both therapeutic biomolecules and research reagents. Massively parallel DNA sequencing can be used to assist antibody selection by comprehensively monitoring libraries during selection, thus greatly expanding the power of these systems. We have therefore constructed a rationally designed, fully defined single-chain variable fragment (scFv) library and analysis platform optimized for analysis with short-read deep sequencing. Sequence-defined oligonucleotide libraries encoding three complementarity-determining regions (L3 from the light chain, H2 and H3 from the heavy chain) were synthesized on a programmable microarray and combinatorially cloned into a single scFv framework for molecular display. Our unique complementarity-determining region sequence design optimizes for protein binding by utilizing a hidden Markov model that was trained on all antibody-antigen cocrystal structures in the Protein Data Bank. The resultant ∼10
12
-member library was produced in ribosome-display format, and comprehensively analyzed over four rounds of antigen selections by multiplex paired-end Illumina sequencing. The hidden Markov model scFv library generated multiple binders against an emerging cancer antigen and is the basis for a next-generation antibody production platform.
Upstream Movement of Juvenile Coho Salmon in Relation to Environmental Conditions in a Culvert Test Bed
Authors: Johnson Gary E. , Pearson Walter H. , Southard Susan L. , Mueller Robert P.
Published: October 2012

We measured the upstream passage success of juvenile coho salmon Oncorhynchus kisutch in relation to select experimental factors in a culvert test bed at a salmon rearing facility on the Skookumchuk River in western Washington State. Passage success, the term used for the response variable, was defined as the number of fish in the headwater tank at the end of the test divided by the number of fish released in the tailwater pool at the beginning of the test (2‐ to 17‐h test periods). Passage success was higher for large (139 mm fork length [FL]) than small (55 mm FL) fish, was higher at night than during the day, was not affected by shading, decreased as tailwater pool depth increased (22.9–53.3 cm), and did not differ significantly among the fish densities tested in the tailwater pool (35–141 fish/m3). There was a clear, negative exponential trend in the response relationship between transformed (arcsine of the square root) passage success and culvert discharge (0.028–0.099 m3/s; mean velocities, 0.59–0.98 m/s). The horizontal distribution of fish moving upstream that successfully exited the culvert into the headwater tank was skewed to the right side of the inlet where the reduced‐velocity zone (RVZ) was located. This observation supported the RVZ hypothesis about upstream movement of juvenile salmon in a culvert—fish accomplish upstream movements in roughened culverts via pathways in the low‐velocity, low‐turbulence boundary layer. To facilitate salmonid passage at road crossings, the preferred resource management alternatives are bridges or stream simulation, but in situations where these approaches are constrained by cost or logistics, the hydraulic design of culverts may be appropriate. The findings from these experiments in the culvert test bed are applicable to hydraulic designs of culverts where upstream passage of juvenile salmon is a concern.
The contemporary practice of state recognition: Kosovo, South Ossetia, Abkhazia, and their aftermath
Authors: Fabry Mikulas
Published: October 2012

This paper assesses state recognition, the practice historically employed to regulate membership in international society, since the United States–led recognition of Kosovo and the Russian-led recognition of South Ossetia and Abkhazia. Its main goal is to succinctly examine the question of whether these two controversial episodes have signaled change in the existing norms of recognition of new states. The paper argues that there is not enough evidence for the claims of some observers and governments that unilateral secession is, as such, becoming legitimate internationally. The leading recognizing powers took great care in all three cases to reject the applicability of their decision to other situations of unilateral secession, and they have since approached those other situations as if no acknowledgment of the three territories had taken place. Nevertheless, there can be little doubt that the deeply contested nature of these cases has introduced confusion and uncertainty into the practice and that this has had, and will have, important implications elsewhere in the world, in terms of both re-invigorated claims of statehood and the potential for unilateral recognition decisions by powerful outsiders. In fact, it is extremely unlikely that Russia's recognition of South Ossetia and Abkhazia in August 2008 would have ever occurred without the prior US-led recognition of Kosovo in February 2008.
Karabakh conflict after Kosovo: no way out?
Authors: Cheterian Vicken
Published: October 2012

A series of events in 2008 influenced the Karabakh conflict resolution efforts: the Kosovo declaration of independence, the August war, and Russian recognition of independent Abkhazia and South Ossetia. Two new diplomatic initiatives to resolve the Karabakh conflict were launched immediately after the August war, one by Russia and the second by Turkey. This article discusses why the two initiatives failed, and the structural problems of Karabakh conflict resolution efforts.
Investigating eating disorders in elite gymnasts: Conceptual, ethical and methodological issues
Authors: Tan Jacinta , Bloodworth Andrew , McNamee Mike , Hewitt Jeanette
Published: October 2012

Elite gymnastics, and other sports where athletes and coaches are particularly concerned with aesthetic considerations, weight and shape, are fields within which the risk of eating disorders may be unusually high. Adolescent gymnasts, developing their own sense of self, at a time of life where body image concerns are common, often compete at the very top of the sport with a need to maintain a body shape and weight optimal for elite performance. Research into this field should address the range of sociological and ethical aspects of eating disorders in elite sport, their prevalence as well as the ethos of the sport itself. This paper addresses a range of conceptual, ethical and methodological issues relevant to conducting research in this sensitive yet important field.
Laurie Boyer: Stem cell circuitry for commitment
Authors: Sedwick Caitlin
Published: October 2012

Boyer studies the genetic programs governing lineage commitment in pluripotent stem cells.
Tiam1 interaction with the PAR complex promotes talin-mediated Rac1 activation during polarized cell migration
Authors: Wang Shujie , Watanabe Takashi , Matsuzawa Kenji , Katsumi Akira , Kakeno Mai , Matsui Toshinori , Ye Feng , Sato Kazuhide , Murase Kiyoko , Sugiyama Ikuko , Kimura Kazushi , Mizoguchi Akira , Ginsberg Mark H. , Collard John G. , Kaibuchi Kozo
Published: October 2012

Migrating cells acquire front-rear polarity with a leading edge and a trailing tail for directional movement. The Rac exchange factor Tiam1 participates in polarized cell migration with the PAR complex of PAR3, PAR6, and atypical protein kinase C. However, it remains largely unknown how Tiam1 is regulated and contributes to the establishment of polarity in migrating cells. We show here that Tiam1 interacts directly with talin, which binds and activates integrins to mediate their signaling. Tiam1 accumulated at adhesions in a manner dependent on talin and the PAR complex. The interactions of talin with Tiam1 and the PAR complex were required for adhesion-induced Rac1 activation, cell spreading, and migration toward integrin substrates. Furthermore, Tiam1 acted with talin to regulate adhesion turnover. Thus, we propose that Tiam1, with the PAR complex, binds to integrins through talin and, together with the PAR complex, thereby regulates Rac1 activity and adhesion turnover for polarized migration.