bluuebunny/crossref_metadata_2025 huggingface dataset:
Gestational 30% and 40% fat diets increase brain GLUT2 and neuropeptide Y immunoreactivity in neonatal Wistar rats
Authors: Cerf Marlon E. , Williams Keith , van Rooyen Jacques , Esterhuyse Adriaan J. , Muller Christo J. , Louw Johan
Published: July 2010

Adverse maternal nutrition induces developmental programming in progeny thereby predisposing them to metabolic disease. The aim of the study was to determine whether maternal diets, with varying fat percentages as energy, alter the expression of factors associated with brain glucose sensing (glucose transporter 2 and glucokinase) and the feeding response (neuropeptide Y and leptin). Pregnant dams were maintained on diets of 10% (control), 20% (20F), 30% (30F) and 40% (40F) fat as energy throughout gestation. In 1‐day‐old neonatal offspring, anthropometric measurements were recorded. Whole neonatal brain was rapidly excised, weighed and either snap‐frozen at −80 °C for quantitative RT‐PCR or fixed in formalin for immunohistochemical analysis. Brain glucose transporter 2, glucokinase, neuropeptide Y and leptin mRNA expression and immunoreactivity were determined in neonates. In the 20F neonates increases in body weight, head circumference and crown to rump length concomitant with reduced glucokinase immunoreactivity were found. The 30F neonates displayed increases in body weight, head length, head width, crown to rump length and immunoreactivity for both glucose transporter 2 and neuropeptide Y. The 40F neonates also demonstrated increased glucose transporter 2 and neuropeptide Y immunoreactivity.

Fetal exposure to a gestational diet with 30% or 40% fat as energy results in increased immunoreactivity for brain glucose transporter 2 and neuropeptide Y, suggesting a programming effect of these diets that may represent an early event of obesity.
Pathogen resistance in the mothOrgyia antiqua: direct influence of host plant dominates over the effects of individual condition
Authors: Sandre S.-L. , Tammaru T. , Hokkanen H.M.T.
Published: July 2010

The role of pathogens in insect ecology is widely appreciated but remains insufficiently explored. Specifically, there is little understanding about the sources of the variation in the outcome of insect-pathogen interactions. This study addresses the extent to which immune traits of larvae and pupae of the mothOrgyia antiquaL. (Lepidoptera: Lymantriidae) depend on the host plant species and individual condition of the insects. The two host plants,Salix myrsinifoliaSalisb. andS. viminalisL., were chosen because they differ in the concentration of phenolic glycosides, harmful to most polyphagous insects. Individual condition was assumed to be reflected in body weight and development time, and was manipulated by rearing larvae either singly or in groups of four. The resistance traits recorded were survival and time to death after fungal infection in the larval stage and the efficiency of encapsulating a nylon implant by the pupae. The survival of the infected larvae was mainly determined by the species of the host plant. Encapsulation response was not associated with the resistance to the pathogen, suggesting that the host plant affected the pathogen rather than the immune system of the insect. Interestingly, the host plant supporting better larval growth led to inferior resistance to the pathogen, indicating a trade-off between different aspects of host plant quality.
Biometric relationships of the Argentinean prawn Artemesia longinaris (Decapoda: Penaeidae) in the south-western Atlantic
Authors: Dumont L.F.C. , D'Incao F.
Published: July 2010

Biometric relationships of size and weight were estimated for the Argentinean prawn (Artemesia longinaris), a new commercial penaeid prawn exploited in the south-western Atlantic. Morphometric and meristic traits were used to elucidate population structure of this species along its distribution area. The morphological relationships were estimated by a simple linear regression, considering total length (TL) as the dependent variable. The males collected in southern Brazil, an area under influence of the Subtropical Convergence, presented a slightly lower TL increment than females. A marked reduction in slopes of males between populations from southern Brazil was observed in autumn and winter. Additionally, relative growth in length of males from Argentina is similar to that observed during autumn and winter in southern Brazil. The other morphometric and meristic variables used also indicated higher similarities between southern Brazil and Argentina, which may be explained by relative growth associated to water temperatures or migration during winter, taking advantage of the oceanographic systems connecting both sites. Moreover, the population from Rio de Janeiro seems morphologically apart from the others, forming a separate unit stock.
Distribution pattern of GFP (green fluorescent protein) in a bivalve-inhabiting hydrozoan, Eutima japonica (Leptomedusae: Eirenidae)
Authors: Kubota Shin , Nomaru Eriko , Uchida Hiroko , Murakami Akio
Published: July 2010

Bright green auto-fluorescence was observed in the umbrellar margin, umbrellar marginal warts, tentacular bulbs, tentacles, and manubrium of laboratory-reared immature (1–14 days old) medusae of Eutima japonica from Japan and China. In vivo microscopic fluorescence spectra showed that the green fluorescence was similar to that of green fluorescent protein (GFP) found in Aequorea victoria, although the maximum emission wavelength (503 nm) was slightly bluer. No fluorescence was detected in the cirri, statocysts, radial canals, velum, or subumbrella of the medusae. The fluorescence distribution pattern in E. japonica more closely resembles that of Eugymnanthea inquilina from the Mediterranean Sea than that of Japanese Eugymnanthea japonica, which is the derived species of E. japonica. This suggests that the common fluorescence pattern is convergently evolved in the former two species, perhaps owing to the as yet unclarified physiological and/or ecological function of GFP and/or GFP-like proteins.
Photobiology of the symbiotic acoel flatwormSymsagittifera roscoffensis: algal symbiont photoacclimation and host photobehaviour
Authors: Serôdio João , Silva Raquel , Ezequiel João , Calado Ricardo
Published: July 2010

The symbiotic association between the acoel flatwormSymsagittifera roscoffensisand the prasinophyte microalgaeTetraselmis convolutaewas studied regarding its photophysiology and photobehaviour. The photoacclimation status and the photophysiological responses to high light of the algal endosymbiont were studied non-destructively on individualS. roscoffensisusing pulse amplitude modulated fluorometry. Specimens collected in an intertidal sandy shore were characterized regarding the maximum quantum yield of photosystem II (PSII),Fv/Fm, and the light response of photosynthetic activity, by constructing rapid light-response curves of the relative electron transport rate of PSII, rETR. The studied population could be considered as high light-acclimated when compared with other intertidal photosynthetic organisms (e.g. macroalgae), with the light-saturation parameterEkaveraging 250 μmol m−2s−1. Light stress experiments showedS. roscoffensisto be able to withstand the exposure to high light without displaying signs of photoinhibition, suggesting the operation of efficient physiological photoprotective processes. The photobehaviour ofS. roscoffensiswas studied by characterizing the distribution of the flatworms under a light gradient, using a custom-made photoaccumulation chamber. The results showed a photoaccumulation pattern evidencing a clear avoidance of extreme low or high light levels, and with maximum photoaccumulation values being found for a range of irradiances (150–400 μmol m−2s−1) that generally coincided with the optima for photosynthetic activity. This matching between the optimum light levels for photosynthetic activity and photoaccumulation suggested thatS. roscoffensismay use vertical migration as a form of behavioural photoprotection. This behavioural response may be used to rapidly and flexibly control light exposure, avoiding photodamage to the endosymbiont photosynthetic apparatus by direct exposure to sunlight.
First insights into the biochemistry ofSabella spallanzanii(Annelida: Polychaeta) mucus: a potentially unexplored resource for applicative purposes
Authors: Stabili Loredana , Schirosi Roberto , Di Benedetto Angela , Merendino Alessandro , Villanova Luciano , Giangrande Adriana
Published: July 2010

Although mucus plays many different roles among marine invertebrates, relatively little is known about the link between biochemical structure and function. In the present study we focused on some physical and chemical properties of the polychaeteSabella spallanzanii's mucus such as viscosity, osmolarity, electrical conductivity, elemental composition, the protein and carbohydrate content, the total lipids and fatty acid composition, and polychlorinated biphenyls (PCBs) contamination. Moreover, an antimicrobial activity of the mucus was investigated. The water content ofS. spallanzaniimucus was 96.2±0.3%. By dry weight 26±1.2% was protein, 8±0.21% was carbohydrate and only 0.1% lipid, much of the remainder of the dry weight was inorganic (about 65.2%). The estimated PCBs content was <0.005 μg g−1. The mucus ofS. spallanzaniiexerted a natural lysozyme-like activity and producedin vitrothe growth inhibition ofVibrio anguillarum, Vibrio harveyi, Pseudomonas aeruginosaandCandida albicans.The findings from this study contribute to improve the limited knowledge available on the mucus composition in invertebrates and have implications for future investigations related to employment ofS. spallanzaniimucus as a source of compounds of pharmaceutical and marine technological interest.
Pacific Epimeriidae (Amphipoda: Crustacea):Epimeria
Authors: Lörz A.N.
Published: July 2010

Epimeriidae is an amphipod family with a worldwide distribution. A new species was found from the Tasman Sea at a depth of 12 m depth and described in detail.Epimeria norfanzisp. nov. can be distinguished from otherEpimeriaby a combination of the following characters: coxal plates 1–3 ventrally rounded; protrusion of coxa 5 reaching the distal end of epimeral plate 2; and urosomite 1 with dorsal keel, telson not cleft. This new species increases the number of PacificEpimeriaspecies to ten. A brief synopsis of the PacificEpimeriaspecies is given and a key provided.
The relevance of Kant's objection to Anselm's ontological argument
Authors: HEATHWOOD CHRIS
Published: July 2010

The most famous objection to the ontological argument is given in Kant's dictum that existence is not a real predicate. But it is not obvious how this slogan is supposed to relate to the ontological argument. Some, most notably Alvin Plantinga, have even judged Kant's dictum to be totally irrelevant to Anselm's version of the ontological argument. In this paper I argue, against Plantinga and others, that Kant's claim is indeed relevant to Anselm's argument, in the straightforward sense that if the claim is true, then Anselm's argument is unsound.
A LEAP OF FAITH: COMPOSING IN THE WASTELAND OF POSTMODERNISM
Authors: Livingston Cecilia
Published: July 2010

In the first composition class I ever took, the professor began by asking us why we wanted to compose. This was a question I had been wrestling with for some time; I had just switched programs at my university and had needed to justify, to myself at least, why I should have taken the biggest risk of my academic career thus far. The question, put so baldly by this professor, had never actually been asked by anyone else when I announced that I wanted to change my course; secretly, I was glad of this, for I felt the answer was too personal and private and new to me to survive any kind of display, or attack.
Knowing and judging in International Relations theory: realism and the reflexive challenge
Authors: HAMATI-ATAYA INANNA
Published: July 2010

This article addresses the notion of reflexivity in international theory through an attempt to transcend the dichotomy between knowledge and judgement. It intends to demonstrate that neither ‘philosophical’ nor ‘scientific’ approaches to world politics can reconcile cognitive and evaluative claims, but that such an endeavour may be envisaged within a certain conception of knowledge, science and facts. A comparison of Morton Kaplan's approach with Hans Morgenthau's and Kenneth Waltz's suggests what kind of theoretical alternatives can bring together these two seemingly incommensurable orders of discourse under a unified, foundationally reflexive epistemology.
Trading sovereignty for stability? The political economy of monetary integration
Authors: RUSSELL JESSE
Published: July 2010

How do states attempt to mitigate the pressures of financial globalisation? This article suggests that options can be understood in terms ofmonetary regimechoice. These are best understood with their international component included – whether states integrate unilaterally, integrate multilaterally, or go it alone monetarily. But to understand the international side of monetary relations, one must look to domestic political structures, histories and politics. It is important that to understand that within the pressures of the international system, domestic politics is afons et origodetermining the health and stability of international economic relations.
Law, caution: towards a better understanding of law for IR theorists
Authors: SINCLAIR ADRIANA
Published: July 2010

The aim of this article is to provide International Relations (IR) theorists with a better understanding of law. This is important forallIR theorists, not just those who focus on international law, because the legalistic way of viewing the world colours all aspects of our world, from teaching us what justice is and providing the means to achieve it, to framing our understanding of human relations and giving us the language of rights with which to articulate it. This article has two main goals: first, to question our own assumptions about law; and second, to introduce IR theorists to the basics of legal methodology and demonstrate how law actually operates.
Significance of time-of-flight ion energy spectrum on energy deposition into matter by high-intensity pulsed ion beam
Authors: Xin J.P. , Zhu X.P. , Lei M.K.
Published: July 2010

Energy deposition by high-intensity pulsed ion beam into a metal target has been studied with time-of-flight (TOF) of ions which can be related to the original ion kinetic energy E0 and the ion mass with $t_{\rm TOF} \propto 1/\sqrt{2E_{0}/m_{i}}$. It is found that the TOF effect has a profound influence on the kinetic energy distribution of implanted ions and subsequent energy deposition process into the target. The HIPIB of mixed H+ and C+ was extracted from a magnetically insulated ion diode at a peak accelerating voltage of 350 kV, leading to an ion current density of 300 A/cm2 at the target. The widespread ion energy spectrum remarkably varied in shape as arriving at the target surface, from the original Gaussian-like of 80-ns duration to a pulse form of a sharp front and a long tail extending to about 140-ns duration. Energy loss of the mixed ions into a Ti target was simulated utilizing a Monte Carlo method. The energy deposition generally showed a shallowing trend and could be divided into two phases proceeded with sequent arrivals of H+ and C+. Note that, the peak value of deposited energy profile appeared at the beginning of mixed ion irradiation phase, other than the phase of firstly arrived H+ with peak kinetic energy and peak ion current. This study indicated that TOF effect of ions greatly affects the HIPIB-matter interaction with a kinetic energy spectrum of impinging ions at the target, noticeably differing from that of original output of the ion source; consequently, the specific energy deposition phenomena of the widespread ion energy can be studied with the TOF correlation of ion energy and ion current, otherwise not obtainable in common cases assuming fixed ion energy distribution in accordance with the original source output.
The Great Depression analogy
Authors: Bordo Michael , James Harold
Published: July 2010

In the discussion of our contemporary economic disease, the Great Depression analogy refuses to go away. Almost every policy-maker referred to conditions that had ‘not been seen since the Great Depression’, even before the failure of Lehman. Some even went further – the Deputy Governor of the Bank of England notably called the crisis the worst ‘financial crisis in human history’. In its April 2009World Economic Outlook, the IMF looked explicitly at the analogy not only in the collapse of financial confidence, but also in the rapid decline of trade and industrial activity across the world. In general, history rather than economic theory seems to offer a guide in interpreting wildly surprising and inherently unpredictable events. Some observers, notably Paul Krugman, have concluded that a Dark Age of macroeconomics has set in.
Isometries on extremely non-complex Banach spaces
Authors: Koszmider Piotr , Martín Miguel , Merí Javier
Published: July 2010

Given a separable Banach spaceE, we construct an extremely non-complex Banach space (i.e. a space satisfying that ‖ Id +T2‖ = 1 + ‖T2‖ for every bounded linear operatorTon it) whose dual containsE* as anL-summand. We also study surjective isometries on extremely non-complex Banach spaces and construct an example of a real Banach space whose group of surjective isometries reduces to ±Id, but the group of surjective isometries of its dual contains the group of isometries of a separable infinite-dimensional Hilbert space as a subgroup.
Solar activity dependence of ion upflow in the polar ionosphere observed with the European Incoherent Scatter (EISCAT) Tromsø UHF radar
Authors: Ogawa Y. , Buchert S. C. , Sakurai A. , Nozawa S. , Fujii R.
Published: July 2010

The influence of solar activity upon ion upflow in the polar ionosphere was investigated using data obtained by the European Incoherent Scatter (EISCAT) Tromsø UHF radar between 1984 and 2008. In agreement with other work we find that the upward ion flux is generally higher when solar activity is high than when it is low. Ion upflow events and also the upward velocity behave the opposite: they are more frequently seen and higher, respectively, at times of low solar activity. In any year about 30–40% ion upflow is accompanied by ∼500 K higher electron temperature than the background temperature at 400 km altitude. Electron and ion heating in connection with upflow is nearly twice as prevalent during high solar activity as it is at low activity. The acceleration of ions by pressure gradients and ambipolar electric field becomes larger when solar activity is low than when it is high. This variation of the average acceleration is caused by the different shapes of electron density profiles for low and high solar activities. Ions start to flow up at above 450 km altitude when solar activity was high, and lower, at 300–500 km altitude, at low solar activity. It is suggested that the solar activity influences long‐term variations of the ion upflow occurrence because it modulates the density of neutral particles, the formation of the F2 density peak, and ion‐neutral collision frequencies in the thermosphere and ionosphere.
Gigantic jets with negative and positive polarity streamers
Authors: Chou J. K. , Kuo C. L. , Tsai L. Y. , Chen A. B. , Su H. T. , Hsu R. R. , Cummer S. A. , Li J. , Frey H. U. , Mende S. B. , Takahashi Y. , Lee L. C.
Published: July 2010

The ISUAL gigantic jets (GJs) are categorized into three types from their generating sequence and spectral properties. Generating sequence of the type I GJs resembles that reported previously; after the fully developed jet (FDJ) established the discharge channel, the ISUAL photometers registered a peak that was from a return‐stroke‐like process. The associated ULF (ultra‐low‐frequency) sferics of these type I GJs indicates that they are negative cloud‐to‐ionosphere discharges (−CIs). Type II GJs begin as blue jets and then developed into GJs in ∼100 ms. Blue jets also frequently occurred at the same region before and after the type II GJs. No identifiable ULF sferics of the type II GJs were found, though an extra event that has +CI ULF signature is probably a type II GJ. The FDJ streamer brightness of the type I GJs is ∼3.4 times of that of the type II GJs. These evidences suggest that the type II GJs are composed of positive streamers. Type III GJs were preceded by lightning, and a GJ subsequently occurred near this preceding lightning. The spectral data of the type III GJs are dominated by lightning signals and the ULF data have high background noise; thus both cannot be properly analyzed. However, the average brightness of the type III GJs falls between those of the other two types of GJs. We propose that the discharge polarity of the type III GJs can be either negative or positive, depending on the type of the charge imbalance left by the trigger lightning.
Ionospheric positive storm phases at the magnetic equator close to sunset
Authors: Huang C. M. , Chen M. Q. , Liu J. Y.
Published: July 2010

During geomagnetic activities, perturbed electric fields at middle and low latitudes of the ionosphere may result from the effect of prompt penetration from high latitudes and the disturbance dynamo mechanism, respectively. The polarity of penetration electric fields depends on the orientation of the interplanetary magnetic field (IMF) Bz, and that of electric fields associated with the disturbance dynamo is almost opposite to that in the quiet time condition. Although a few hours are required to build up the perturbed electric fields through the disturbance dynamo mechanism, the dynamo electric fields can persist for several hours after geomagnetic activities cease. It turns out that the low‐latitude electric field disturbances associated with the disturbance dynamo mechanism should be more persistent than that associated with the direct penetration from the polar cap, especially for the period in the recovery phase. Model results show a significant, westward disturbance dynamo electric field at period close to sunset, but it seems not important in the empirical model. This perturbed electric field at sunset will weaken the intensity of the prereversal enhancement and of the following fountain effect in the storm time. Relative to the quiet time condition, it produces an enhancement in the total electron content. This phenomenon is seasonal. It only occurs at period close to equinox, when the hemispheric wind (summer to winter) is minimal. These theoretical results have been substantiated by model results of the National Center for Atmospheric Research Thermosphere Ionosphere Electrodynamics General Circulation Model and by the global integration and modeling in this study. Both results show that the positive phase of the ionospheric storm at the magnetic equator close to sunset is produced by the westward disturbance dynamo electric field.
On the reconstruction of magnetospheric plasma pressure distributions from empirical geomagnetic field models
Authors: Tsyganenko N. A.
Published: July 2010

Four data‐based models of the magnetospheric magnetic field were tested for the degree of their consistency with a static balance between the magnetic and plasma stresses. To that end, best fit distributions of the plasma sheet pressure and its anisotropy were derived in the midnight meridian plane, using two specific forms of the particle distribution function. The tailward limit of the modeling region was placed at R = 20 RE, where the condition of pressure balance with the tail lobe field was used to avoid the multiplicity of solutions of the force balance equation. Best fit solutions were derived by minimizing the rms difference between the magnetic and plasma stress vectors over a set of points within the model plasma sheet at distances 5 ≤ R ≤ 20 RE. The obtained equatorial profiles of P⊥ and P∥ demonstrate a steep decrease of both pressures from the inner to outer boundary and a strong overall increase from quiet to disturbed conditions. The anisotropy ratio β = P∥/P⊥ was found to significantly deviate from unity in the case of TU82 and T87 models, with progressively higher values of β at larger tailward distances. By contrast, more recent T89 and T96 models yielded more realistic results with nearly isotropic pressure in the tail and a moderate pancake‐type anisotropy in the inner magnetosphere, consistent with observations.
Global simulation of EMIC wave excitation during the 21 April 2001 storm from coupled RCM‐RAM‐HOTRAY modeling
Authors: Chen Lunjin , Thorne Richard M. , Jordanova Vania K. , Wang Chih‐Ping , Gkioulidou Matina , Lyons Larry , Horne Richard B.
Published: July 2010

The global distribution and spectral properties of electromagnetic ion cyclotron (EMIC) waves in the He+ band are simulated for the 21 April 2001 storm using a combination of three different codes: the Rice Convection Model, the Ring current‐Atmospheric interactions Model, and the HOTRAY ray tracing code (incorporated with growth rate solver). During the storm main phase, injected ions exhibit a non‐Maxwellian distribution with pronounced phase space density minima at energies around a few keV. Ring current H+ injected from the plasma sheet provides the source of free energy for EMIC excitation during the storm. Significant wave gain is confined to a limited spatial region inside the storm time plume and maximizes at the eastward edge of the plume in the dusk and premidnight sector. The excited waves are also able to resonate and scatter relativistic electrons, but the minimum electron resonant energy is generally above 3 MeV.
Ionization sources in Titan's deep ionosphere
Authors: Galand Marina , Yelle Roger , Cui Jun , Wahlund Jan‐Erik , Vuitton Véronique , Wellbrock Anne , Coates Andrew
Published: July 2010

We analyze a multi‐instrumental data set from four Titan encounters by the Cassini spacecraft to investigate in detail the formation of the ionosphere. The data set includes observations of thermospheric and ionospheric species and suprathermal electrons. A model describing the solar and electron energy deposition is used as an organizing element of the Cassini data set. We first compare the calculated secondary electron production rates with the rates inferred from suprathermal electron intensity measurements. We then calculate an effective electron dissociative recombination coefficient, applying three different approaches to the Cassini data set. Our findings are threefold: (1) The effective recombination coefficient derived under sunlit conditions in the deep ionosphere (<1200 km) is found to be independent of solar zenith angle and flyby. Its value ranges from 6.9 × 10−7 cm3 s−1 at 1200 km to 5.9 × 10−6 cm3 s−1 at 970 km at 500 K. (2) The presence of an additional, minor source of ionization is revealed when the solar contribution is weak enough. The contribution by this non‐solar source—energetic electrons most probably of magnetospheric origin—becomes apparent for secondary electron production rates, due to solar illumination alone, close to or smaller than about 3 × 10−1 cm−3 s−1. Such a threshold is reached near the solar terminator below the main solar‐driven electron production peak (<1050 km). (3) Our ability to model the electron density in the deep ionosphere is very limited. Our findings highlight the need for more laboratory measurements of electron dissociative recombination coefficients for heavy ion species at high electron temperatures (especially near 500 K).
Principal modes of thermospheric density variability: Empirical orthogonal function analysis of CHAMP 2001–2008 data
Authors: Matsuo Tomoko , Forbes Jeffrey M.
Published: July 2010

In this paper we characterize the dominant modes of global thermosphere density variability as empirical orthogonal functions (EOFs) using densities obtained from the accelerometer experiment on board the CHAMP satellite during 2001–2008. We determine the significance of different types of thermospheric density variability to the overall density variation and also examine the drivers of these primary modes of variability. From a sequential nonlinear regression analysis of the density observations along satellite trajectories, we obtain a set of EOFs in magnetic latitude and magnetic local time coordinates and their orbit time‐dependent amplitudes. EOF1 includes a strong global mean component and takes the form of the diurnal variation. It correlates highly with the daily F10.7 index. It underscores that solar EUV is by far the strongest driver of the overall thermospheric density variability. Additionally, the primary mode is modulated semiannually, and its magnitude decreases with declining solar activity. EOF2 has a hemispherically asymmetric structure and represents the summer‐to‐winter annual density variation. Density responses to geomagnetic forcing are primarily manifested in three different modes: EOF1 that represents the global mean response, EOF3 that has a pronounced magnetic local time‐dependent feature, and EOF4, whose main features are high‐latitude density increases. These modes have very different response time scales with respect to changes in solar wind parameters. In addition, EOF3 and EOF4 contain signatures of local time variability that are possibly connected with the effects of a solar terminator wave and high‐order solar tides that propagate upward from the lower atmosphere and/or with local plasma‐neutral interactions in the F region.
GPS TEC response to the 22 July 2009 total solar eclipse in East Asia
Authors: Ding Feng , Wan Weixing , Ning Baiqi , Liu Libo , Le Huijun , Xu Guirong , Wang Min , Li Guozhu , Chen Yiding , Ren Zhipeng , Xiong Bo , Hu Lianhuan , Yue Xinan , Zhao Biqiang , Li Fengqin , Yang Min
Published: July 2010

The longest total solar eclipse of this century occurred in East and South Asia on 22 July 2009. The eclipse was accompanied with a medium magnetic storm, whose main phase onset occurred ∼27 min after the passage of the Moon's umbral shadow. Using TEC data from 60 GPS stations, we construct differential TEC maps to investigate the ionosphere response to the solar eclipse in central China in the range of 26°N–36°N, 108°E–118°E (i.e., the magnetic latitude 15°N–25°N). During the eclipse's totality, a “shadow” in the ionosphere shown as TEC depletion area was formed ∼100 km south of the Moon's umbral path with a maximum decrease of 5 TECU. The TEC depletion area moved eastward, following the movement of the totality area with a time lag of ∼10 min. Enhancements of TEC due to the storm are observed after the main phase onset. The relative drop of TEC due to the solar eclipse is evidently larger at lower latitudes than that at higher ones and around noontime than that in the morning. By modeling work, we find that the latitudinal dependence of the TEC response may result from latitudinal variation of magnetic inclination, which influences the diffusion of ionization among different layers. Besides, the local time dependence of TEC response is closely related to the local time variation of background atmosphere density, which affects the electron loss efficiency in the ionosphere.
Equatorward moving arcs and substorm onset
Authors: Haerendel Gerhard
Published: July 2010

Key observations of phenomena during the growth phase of a substorm are being reviewed with particular attention to the equatorward motion of the hydrogen and electron arcs. The dynamic role of the electron, the so‐called growth phase arc, is analyzed. It is part of a current system of type II that is instrumental in changing the dominantly equatorward convection from the polar cap into a sunward convection along the auroral oval. A quantitative model of the arc and associated current system allows determining the energy required for the flow change. It is suggested that high‐β plasma outflow from the central current sheet of the tail creates the current generator. Assessment of the energy supplied in this process proves its sufficiency for driving the arc system. The equatorward motion of the arcs is interpreted as a manifestation of the shrinkage of the near‐Earth transition region (NETR) between the dipolar magnetosphere and the highly stretched tail. This shrinkage is caused by returning magnetic flux to the dayside magnetosphere as partial replacement of the flux eroded by frontside reconnection. As the erosion of the NETR is proceeding, more and more magnetic flux is demanded from the central current sheet of the near‐Earth tail until highly accelerated plasma outflow causes the current sheet to collapse. Propagation of the collapse along the tail triggers reconnection and initiates the substorm.
Long‐term total ozone observations at Arosa (Switzerland) with Dobson and Brewer instruments (1988–2007)
Authors: Scarnato B. , Staehelin J. , Stübi R. , Schill H.
Published: July 2010

Dobson and Brewer spectrophotometers are the standard instruments for ground‐based total ozone monitoring under the World Meteorological Organization's Global Atmosphere Watch program. Both types of instruments have been simultaneously used at Arosa station (Switzerland) since 1988; presently two Dobson and three Brewer instruments (one of which is type Mark III) are in operation. The large data set of quasi‐simultaneous measurements (defined here as observations performed less than 10 min apart) allows for the determination of both inter‐ and intrainstrumental precision. The results for one standard deviation of total ozone are ±0.5% for Dobson standard wavelength pair observations and ±0.15% for Brewer total ozone measurements. To transform Dobson data into Brewer total ozone observations, empirical transfer functions are used to describe the observed difference in seasonal variations of total ozone data derived from the two types of instruments (amounting to a seasonal amplitude of approximately 2% with maximum deviation in winter). The statistical model (applied to quasi‐simultaneous measurements) includes the ozone effective temperature and the air mass multiplied by total ozone (ozone slant path) as explanatory variables; it removes the seasonal cycle in the difference and it allows the significance of the proxies introduced and systematic errors in the data to be determined. However, even when these transfer functions are applied, a 3% drift over about a 10 year period (1988–1997) between Arosa's Dobson and Brewer derived total ozone data series remains unexplained, adding to the model an aerosol proxy for which only part of the drift can be removed (related to the period 1992–1996).
Dust emission and transport associated with a Saharan depression: February 2007 case
Authors: Bou Karam Diana , Flamant Cyrille , Cuesta Juan , Pelon Jacques , Williams Earle
Published: July 2010

The dust activity over North Africa associated with the Saharan depression event in February 2007 is investigated by mean of spaceborne observations, ground‐based measurements, and mesoscale simulation with Meso‐NH. The main characteristics of the cyclone as well as the meteorological conditions during this event are described using the European Centre for Medium‐Range Weather Forecasts (ECMWF). The dust storm and cloud cover over North Africa is thoroughly described combining for the first time Spinning Enhanced Visible and Infra‐Red Imager (SEVIRI) images for the spatiotemporal evolution and Cloud‐Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) and CloudSat observations for the vertical distribution. The Saharan depression formed over Algeria in the lee of the Atlas Mountains on the afternoon of 20 February in response to midlatitude trough intrusion. It migrated eastward with a speed of 11 m s−1 and reached Libya on 22 February before exiting the African continent toward the Mediterranean Sea on 23 February. The horizontal scale of the cyclone at the surface varied between 800 and 1000 km during its lifetime. On the vertical the cyclone extended over 8 km, and a potential vorticity of 2 potential vorticity units (PVU) was reported at its center at 3 km in altitude. The cyclone was characterized by a surface pressure anomaly of about 9 hPa with respect to the environment, a warm front typified at the surface by an increase in surface temperature of 5°C, and a sharp cold front characterized by a drop in surface temperature of 8°C and an increase in 10 m wind speed of 15 m s−1. The cyclone provided dynamical forcing that led to strong near‐surface winds and produced a major dust storm over North Africa. The dust was transported all around the cyclone leaving a clear eye at its center and was accompanied by a deep cloud band along the northwestern edge of the cyclone. On the vertical, slanted dust layers were consistently observed during the event over North Africa. Furthermore, the dust was lofted to altitudes as high as 7 km, becoming subject to long‐range transport. The model was able to reasonably reproduce the structure, lifetime, and trajectory of the cyclone. Also, comparison with Moderate Resolution Imaging Spectrometer (MODIS) deep blue aerosol optical depths and CALIPSO‐CloudSat observations suggests that the model can be reliably used to quantify the dust emissions associated with this event. The mean daily dust loads over the area influenced by the cyclone were simulated to range between 2 and 8 Tg during the lifetime of the Sharav cyclone (i.e., 5 days). This study suggests that dust emissions linked with Saharan cyclones may contribute significantly to the total dust load over West and North Africa observed annually.
African dust deposition to Florida: Temporal and spatial variability and comparisons to models
Authors: Prospero Joseph M. , Landing William M. , Schulz Michael
Published: July 2010

Mineral dust plays an important role in ocean biogeochemistry as a source of Fe which in some regions is a limiting micronutrient. Ocean models often use the output of dust transport models to estimate dust‐Fe deposition. However, models have not been adequately tested, because of the dearth of long‐term dust deposition measurements. Here we present the results of a 3 year deposition study in a nine‐station network in Florida which is impacted by African dust every year, and we compare these measurements with estimates from global dust models. Wet deposition (WD) and bulk deposition (BD) rates of soil‐related elements (Al, Fe, and Mn) were highly correlated and remarkably uniform across the state; they exhibited an extremely strong summer maximum that closely matched concurrently measured dust concentrations in Miami. The average dust WD across the network was about 150 μg cm−2 yr−1, and the BD rate was 200 μg cm−2 yr−1. Dry deposition (DD), defined as the difference between BD and WD, was a minor component, about 20–30% of the total. In a comparison with nine dust models in the Aerosol Comparisons between Observations and Models project (AeroCom) database, models correctly characterized the seasonal cycle of deposition but most substantially underestimated summer deposition. The ratios of WD to DD in the models varied greatly, ranging from about 1:1 to 30:1 in contrast to the Florida Atmospheric Mercury Study station ratio, which was about 3:1 to 4:1. These results show a clear need for more dust deposition measurements in regions dominated by oceanic air masses and for a better understanding of the treatment of deposition processes in models.
Long‐term prediction of precipitation and hydrologic extremes with nonstationary oscillation processes
Authors: Lee T. , Ouarda T. B. M. J.
Published: July 2010

Nonstationary oscillations in climatic variables and indices have been the focus of many studies. Since climate indices or their associated hydrometeorological variables might contain nonstationary oscillation processes, it would be useful to be able to divide the intrinsic nonstationary oscillation into a finite number of components. Those components can then be used to predict the future system evolution. In the current study nonstationary oscillations of certain time series are extracted using a decomposition analysis called the empirical mode decomposition (EMD). In EMD the most important components are modeled with a nonstationary oscillation resampling (NSOR) technique. To predict a long‐term oscillation pattern, a time series with a long record is required. The normalized regional precipitation of eastern Canada is one such series. In a second example, the future evolution of extreme streamflows at two stations from the province of Quebec, Canada, is studied by using the long‐term patterns of climatic indices. Results indicate that the future long‐term patterns are well‐modeled with the NSOR and EMD. However, the indirect approach to finding the interconnection sometimes gives rise to a high prediction uncertainty.
Comment on comment by Markus Rapp and Franz‐Josef Lübken on “Ice iron/sodium film as cause for high noctilucent cloud radar reflectivity”
Authors: Bellan P. M.
Published: July 2010

Rapp and Lübken (RL09) state that there is excellent, precise agreement between observations and polar mesosphere summer echo (PMSE) models based on radar reflection by gas‐phase electrons and conclude that because of this excellent, precise agreement other models should not be considered. In particular, they provide figures demonstrating quantitative agreement between observations and a heating/overshoot model. Careful consideration of the models presented by RL09 shows that there are inconsistencies in the assumptions regarding Lambda (i.e., the ratio of the number density of electrons attached to aerosol particles to the number density of free electrons) and there are quantitative errors in the calculation of the radar reflection. In addition, RL09's claim that the correlation between PMSE maximum and bite‐outs is either spurious or misrepresentative is refuted using radar measurements. Finally, it is shown that there is a shortcoming (not discussed by RL09) in the Bellan 2008 model, and a modification addressing this shortcoming is briefly described.
Extratropical tropopause transition layer characteristics from high‐resolution sounding data
Authors: Homeyer Cameron R. , Bowman Kenneth P. , Pan Laura L.
Published: July 2010

Accurate determination of the tropopause is important for applications such as dynamical analysis and forecasting, radiative transfer calculations, and the diagnosis of chemical transport in the atmosphere. In this paper, we examine how well the extratropical tropopause is determined in the National Centers for Environmental Prediction high‐resolution Global Forecast System (GFS) model analysis over the continental United States using high‐resolution aircraft and radiosonde data. The GFS analyses and sounding data compare well, with RMS differences of approximately 600 m, which is comparable to the vertical resolution of the model. The GFS tropopause is a good proxy in areas without in situ observations, but near the subtropical jet the GFS analysis often mistakenly identifies the secondary rather than the primary tropopause. We also explore an alternative method to identify the tropopause by fitting a smoothed step function to the static stability profile. This new approach provides a measure of the depth of the troposphere‐stratosphere transition and facilitates the study of the dynamical behavior of the tropopause region. In particular, using the transition depth, we are able to identify the statistical behavior of temperature in profiles with deep or shallow tropopause transition layers.
Is the spin transition in Fe2+‐bearing perovskite visible in seismology?
Authors: Caracas Razvan , Mainprice David , Thomas Christine
Published: July 2010

We determine the elasticity of FeSiO3 perovskite for various spin configurations using density‐functional theory calculations. The elastic moduli and the bulk seismic wave velocities are weakly affected by the spin transition. However we show that the intrinsic differences in seismic anisotropy between the high‐spin and low‐spin phases of Fe‐bearing perovskite coupled with lattice preferred orientation that can develop due and during the convection may lead to distinct seismic signatures between the top and the bottom of the lower mantle. These signatures should be detectable in observations and they need to be taken into account in tomographic studies of the Earth's lower mantle.
Sensitivity of global ocean biogeochemical dynamics to ecosystem structure in a future climate
Authors: Manizza Manfredi , Buitenhuis Erik T. , Le Quéré Corinne
Published: July 2010

Terrestrial and oceanic ecosystem components of the Earth System models (ESMs) are key to predict the future behavior of the global carbon cycle. Ocean ecosystem models represent low complexity compared to terrestrial ecosystem models. In this study we use two ocean biogeochemical models based on the explicit representation of multiple planktonic functional types. We impose to the models the same future physical perturbation and compare the response of ecosystem dynamics, export production (EP) and ocean carbon uptake (OCU) to the same physical changes. Models comparison shows that: (1) EP changes directly translate into changes of OCU on decadal time scale, (2) the representation of ecosystem structure plays a pivotal role at linking OCU and EP, (3) OCU is highly sensitive to representation of ecosystem in the Equatorial Pacific and Southern Oceans.
The NCX3 Isoform of the Na+/Ca2+ Exchanger Contributes to Neuroprotection Elicited by Ischemic Postconditioning
Authors: Pignataro Giuseppe , Esposito Elga , Cuomo Ornella , Sirabella Rossana , Boscia Francesca , Guida Natascia , Di Renzo Gianfranco , Annunziato Lucio
Published: July 2010

It has been recently shown that a short sublethal brain ischemia subsequent to a prolonged harmful ischemic episode may confer ischemic neuroprotection, a phenomenon termed ischemic postconditioning. Na+/Ca2+ exchanger (NCX) isoforms, NCX1, NCX2, and NCX3, are plasma membrane ionic transporters widely distributed in the brain and involved in the control of Na+ and Ca2+ homeostasis and in the progression of stroke damage. The objective of this study was to evaluate the role of these three proteins in the postconditioning-induced neuroprotection. The NCX protein and mRNA expression was evaluated at different time points in the ischemic temporoparietal cortex of rats subjected to tMCAO alone or to tMCAO plus ischemic postconditioning. The results of this study showed that NCX3 protein and ncx3 mRNA were upregulated in those brain regions protected by postconditioning treatment. These changes in NCX3 expression were mediated by the phosphorylated form of the ubiquitously expressed serine/threonine protein kinase p-AKT, as the p-AKT inhibition prevented NCX3 upregulation. The relevant role of NCX3 during postconditioning was further confirmed by results showing that NCX3 silencing, induced by intracerebroventricular infusion of small interfering RNA (siRNA), partially reverted the postconditioning-induced neuroprotection. The results of this study support the idea that the enhancement of NCX3 expression and activity might represent a reasonable strategy to reduce the infarct extension after stroke.