bluuebunny/crossref_metadata_2025 huggingface dataset:
Nanomaterials Can Dynamically Steer Cell Responses to Biological Ligands
Authors: Sharma Ram I. , Schwarzbauer Jean E. , Moghe Prabhas V.
Published: December 2010

Traditional tissue regeneration approaches to activate cell behaviors on biomaterials rely on the use of extracellular‐matrix‐based or soluble growth‐factor cues. In this article, a novel approach is highlighted to dynamically steer cellular phenomena such as cell motility based on nanoscale substratum features of biological ligands. Albumin‐derived nanocarriers (ANCs) with variable nanoscale‐size features are functionalized with fibronectin III9‐10 matrix ligands, and their effects on primary human keratinocyte activation are investigated. The presentation of fibronectin fragments from ANCs significantly enhances cell migration as compared to free ligands at equivalent concentrations. Notably, cell migration is influenced by the size of the underlying ANCs even for variably sized ANCs covered in comparable levels of fibronectin fragment. For equivalent ligand concentrations, cell migration on the smaller‐sized ANCs (30 and 50 nm) is significantly enhanced as compared to that on larger‐sized ANCs (75 and 100 nm). In contrast, the enhancement of cell migration on nanocarriers is abolished by the use of immobilized, biofunctionalized ANCs, indicating that “dynamic” nanocarrier internalization events underlie the role of nanocarrier geometry on the differential regulation of cell migration kinetics. Uptake studies using fluorescent ANCs indicate that larger‐sized ANCs cause delayed endocytic kinetics and hence could present barriers for internalization during the cell adhesion and motility processes. Motile cells exhibit diminished migration upon exposure to clathrin inhibitors, but not caveolin inhibitors, suggesting the role of clathrin‐mediated endocytosis in facilitating cell migratory responsiveness to the nanocarriers. Overall, a monotonic relationship is found between the nanocarrier cytointernalization rate and the cell migration rate, suggesting the possibility of designing biointerfacial features for the dynamic control of cell migration. Thus, the functionalization of a mobile nanocarrier by a biorelevant ligand can be used to sensitize cellular motility activation to the adhesion ligands, and such nanocarrier interfaces can dynamically attune cell migration kinetics by modulating the uptake of the ligand–nanocarrier complex via nanocarrier size.
Effects of Gold Nanorod Concentration on the Depth‐Related Temperature Increase During Hyperthermic Ablation
Authors: Jang Boseung , Kim Yu Shin , Choi Yongdoo
Published: December 2010

The photothermal properties of gold nanorods (GNRs) provide an opportunity for the clinical application of highly efficient and tumor‐specific photothermal therapy. For the effective hyperthermic ablation of tumor tissue using GNRs, it is essential to maintain a homogeneous therapeutic temperature in the target tissue during treatment. This study investigates whether the concentration of GNRs affects the distribution of the temperature increase during hyperthermal therapy. The investigation is conducted using polyacrylamide phantoms containing varying amounts of GNRs. In 0.1, 0.25, and 0.5 nM GNR‐suspended phantoms, the change in temperature is relatively uniform along the depth of each phantom during laser irradiation at 2 W cm−2. In 1.0, 2.0, and 5.0 nM GNR‐suspended phantoms, the rates of temperature increase in the deep regions of the phantoms decrease with increasing GNR concentration. At a laser irradiation of 5 W cm−2, the temperature of the GNR‐suspended phantoms increases at a faster rate, whereas the range of GNR concentrations for maintaining the homogeneity of the temperature increase is not affected. This suggests that the concentration of GNRs is the major determinant of the depth‐related temperature increase during hyperthermic ablation. Therefore, prior to the clinical application of hyperthermic ablation using GNRs, the concentration of GNRs has to be optimized to ensure a homogeneous distribution of therapeutic temperature in the targeted tissue.
Sleep disturbance associated with an enhanced orexinergic system induced by chronic treatment with paroxetine and milnacipran
Authors: Rahmadi Mahardian , Narita Minoru , Yamashita Akira , Imai Satoshi , Kuzumaki Naoko , Suzuki Tsutomu
Published: December 2010

Recent reports have shown that acute or chronic treatment with selective serotonin reuptake inhibitor (SSRI) or serotonin‐noradrenaline reuptake inhibitor (SNRI) causes unpleasant side effects in patients. In the present study, through the use of electroencephalography (EEG) and electromyography (EMG), we found that chronic treatment with the SSRI paroxetine or the SNRI milnacipran significantly induced sleep disturbance, which was characterized by an increase in the total wake time and decreased total nonrapid eye movement (NREM) sleep. Furthermore, RT‐PCR analysis demonstrated that chronic treatment with paroxetine or milnacipran significantly increased the mRNA levels of orexin 1 receptor and orexin 2 receptor in the hypothalamus and of histamine 1 receptor and histidine decarboxylase in the frontal cortex of mice. The present findings suggest that chronic treatment with either paroxetine or milnacipran causes sleep disturbance associated with an increase in orexinergic transmission in the hypothalamus and histaminergic transmission in the frontal cortex. Although further studies are needed, these imbalances in the orexinergic and histaminergic systems may be, at least in part, responsible for the pathogenesis of sleep disturbance induced by chronic treatment with SSRI or SNRI in rodents. Synapse, 2011. © 2010 Wiley‐Liss, Inc.
Limitation Riders and Congressional Influence over Bureaucratic Policy Decisions
Authors: MACDONALD JASON A.
Published: December 2010

Limitation riders, which allow the U.S. Congress to forbid agencies from spending money for specific uses, enable congressional majorities to exert greater influence over bureaucratic policy decisions than is appreciated by research on policy making in the United States. I develop a theory of limitation riders, explaining why they lead to policy outcomes that are preferable to a majority of legislators compared to outcomes that would occur if this tool did not exist. I assess this perspective empirically by analyzing the volume of limitation riders reported in bills from 1993 to 2002 and all limitation riders forbidding regulatory actions from 1989 to 2009. In addition to supporting the conclusion that Congress possesses more leverage over agencies’ decisions than is currently appreciated, the findings have implications for advancing theories of delegation.
Dietary patterns during pregnancy and the risk of postpartum depression in Japan: the Osaka Maternal and Child Health Study
Authors: Okubo Hitomi , Miyake Yoshihiro , Sasaki Satoshi , Tanaka Keiko , Murakami Kentaro , Hirota Yoshio ,   the Osaka Maternal and Child Health Study Group
Published: December 2010

Although several nutrients and foods are suggested to be preventive against postpartum depression, all previous studies have primarily focused on single nutrients or foods. In contrast, studies on dietary patterns, namely the measurement of overall diet by considering the cumulative effects of nutrient, may provide new insights into the influence of diet on postpartum depression. We prospectively examined the association between dietary patterns during pregnancy and the risk of postpartum depression among 865 Japanese women. Diet was assessed with a validated, self-administered diet history questionnaire. Dietary patterns from thirty-three predefined food groups (energy-adjusted food (g/d)) were extracted by factor analysis. Postpartum depression was defined as present when the subjects had an Edinburgh Postnatal Depression Scale score of ≥ 9 at 2–9 months postpartum. A total of 121 women (14·0 %) were classified as having postpartum depression. Three dietary patterns were identified: ‘Healthy’, ‘Western’ and ‘Japanese’ patterns. After adjustment for potential confounders, neither the ‘Healthy’ nor the ‘Japanese’ pattern was related to the risk of postpartum depression. Compared with the first quartile of the ‘Western’ pattern, only the second quartile was independently related to a decreased risk of postpartum depression (multivariate OR 0·52, 95 % CI 0·30, 0·93), although no evident exposure–response associations were observed (P for trend = 0·36). The present study failed to substantiate clear associations between dietary patterns and the risk of postpartum depression. Further studies with more accurate measurements are warranted to confirm the relationship between dietary patterns and the risk of postpartum depression.
bvca(Σ, X) REVISITED
Authors: FERRANDO J. C.
Published: December 2010

Assuming that (Ω, Σ) is a measurable space and (X) is a Banach space we provide a quite general sufficient condition on (X) for bvca(Σ, X) (the Banach space of all X-valued countably additive measures of bounded variation equipped with the variation norm) to contain a copy of c0 if and only if X does. Some well-known results on this topic are straightforward consequences of our main theorem.
Three-dimensional features in low-Reynolds-number confined corner flows
Authors: GUGLIELMINI LAURA , RUSCONI R. , LECUYER S. , STONE H. A.
Published: December 2010

In recent microfluidic experiments with solutions of bacteria we observed the formation of biofilms in the form of thread-like structures, called ‘streamers’, which float in the middle plane of the channel and are connected to the side walls at the inner corners. Motivated by this observation, we discuss here the pressure-driven low-Reynolds-number flow around a corner bounded by the walls of a channel with rectangular cross-section. We numerically solve the flow field in a channel of constant cross-section, which exhibits 90° sharp corners, or turns with constant curvature, or portions with slowly changing curvature along the flow direction, for finite, but small, values of the Reynolds numbers and including the limit of vanishingly small Reynolds numbers. In addition, we develop a matched asymptotic expansion solution for the flow around two boundaries intersecting at an angle α and spanning the small gap h between two horizontal plates. We illustrate the basic features of the flow in these channel geometries by describing the three-dimensional velocity field and the distribution of streamwise vorticity and helicity, and comparing the numerical solutions with predictions based on the asymptotic approach. We demonstrate that near a corner or a change in the curvature of the side wall the flow is three-dimensional and pairs of counter-rotating vortical structures are present, as identified by Balsa (J. Fluid Mech., vol. 372, 1998, p. 25). Finally, we discuss how this secondary flow depends on the significant geometric parameters, the aspect ratio of the channel cross-section, the radius of curvature of the turn and, more generally, the variation of the curvature of the channel side boundary. We believe that these three-dimensional secondary flow structures are relevant to transport problems where accumulation of material at the boundary is possible.
Direct numerical simulation of spiral turbulence
Authors: DONG S. , ZHENG X.
Published: December 2010

In this paper, we present results of three-dimensional direct numerical simulations of the spiral turbulence phenomenon in a range of moderate Reynolds numbers, in which alternating intertwined helical bands of turbulent and laminar fluids co-exist and propagate between two counter-rotating concentric cylinders. We show that the turbulent spiral is comprised of numerous small-scale azimuthally elongated vortices, which align into and collectively form the barber-pole-like pattern. The domain occupied by such vortices in a plane normal to the cylinder axis resembles a ‘crescent moon’, a shape made well known by Van Atta with his experiments in the 1960s. The time-averaged mean velocity of spiral turbulence is characterized in the radial–axial plane by two layers of axial flows of opposite directions. We also observe that, as the Reynolds number increases, the transition from spiral turbulence to featureless turbulence does not occur simultaneously in the whole domain, but progresses in succession from the inner cylinder towards the outer cylinder. Certain aspects pertaining to the dynamics and statistics of spiral turbulence and issues pertaining to the simulation are discussed.
Convectons, anticonvectons and multiconvectons in binary fluid convection
Authors: MERCADER ISABEL , BATISTE ORIOL , ALONSO ARANTXA , KNOBLOCH EDGAR
Published: December 2010

Binary fluid mixtures with a negative separation ratio heated from below exhibit steady spatially localized states called convectons for supercritical Rayleigh numbers. Numerical continuation is used to compute such states in the presence of both Neumann boundary conditions and no-slip no-flux boundary conditions in the horizontal. In addition to the previously identified convectons, new states referred to as anticonvectons with a void in the centre of the domain, and wall-attached convectons attached to one or other wall are identified. Bound states of convectons and anticonvectons called multiconvecton states are also computed. All these states are located in the so-called snaking or pinning region in the Rayleigh number and may be stable. The results are compared with existing results with periodic boundary conditions.
Stability analysis and breakup length calculations for steady planar liquid jets
Authors: TURNER M. R. , HEALEY J. J. , SAZHIN S. S. , PIAZZESI R.
Published: December 2010

This study uses spatio-temporal stability analysis to investigate the convective and absolute instability properties of a steady unconfined planar liquid jet. The approach uses a piecewise linear velocity profile with a finite-thickness shear layer at the edge of the jet. This study investigates how properties such as the thickness of the shear layer and the value of the fluid velocity at the interface within the shear layer affect the stability properties of the jet. It is found that the presence of a finite-thickness shear layer can lead to an absolute instability for a range of density ratios, not seen when a simpler plug flow velocity profile is considered. It is also found that the inclusion of surface tension has a stabilizing effect on the convective instability but a destabilizing effect on the absolute instability. The stability results are used to obtain estimates for the breakup length of a planar liquid jet as the jet velocity varies. It is found that reducing the shear layer thickness within the jet causes the breakup length to decrease, while increasing the fluid velocity at the fluid interface within the shear layer causes the breakup length to increase. Combining these two effects into a profile, which evolves realistically with velocity, gives results in which the breakup length increases for small velocities and decreases for larger velocities. This behaviour agrees qualitatively with existing experiments on the breakup length of axisymmetric jets.
Longitudinal profile of channels cut by springs
Authors: DEVAUCHELLE O. , PETROFF A. P. , LOBKOVSKY A. E. , ROTHMAN D. H.
Published: December 2010

We propose a simple theory for the longitudinal profile of channels incised by groundwater flow. The aquifer surrounding the stream is represented in two dimensions through Darcy's law and the Dupuit approximation. The model is based on the assumption that, everywhere in the stream, the shear stress exerted on the sediment by the flow is close to the minimal intensity required to displace a sand grain. Because of the coupling of the stream discharge with the water table elevation in the neighbourhood of the channel head, the stream elevation decreases as the distance from the stream's tip with an exponent of 2/3. Field measurements of steephead ravines in the Florida Panhandle conform well to this prediction.
Upskilling the Workers will not Upskill the Work. Why the Dominant Economic Framework Limits Child Poverty Reduction in the UK
Authors: LEWIS PAUL
Published: December 2010

This paper assesses the policy consensus that exists amongst political parties in the UK in their shared ambition to eradicate child poverty by 2020. Three major pillars of policy – work intensification, re-distribution and skill upgrading – are challenged in terms of their likely success in reducing child poverty. In particular, the assumption that upgrading skills will raise earnings is challenged by examining the changing patterns of work in a selection of developed economies since the 1970s. This paper argues that addressing relative poverty requires an alternative theoretical approach to the neoclassical economics that currently underpins policy. Different national levels of earnings dispersion suggest that the role of institutions and culture in determining market outcomes deserves at least as much attention as the supply of skills.
The Role of Canon Law in the Ecumenical Venture: a Roman Catholic Perspective
Authors: Leahy Brendan
Published: December 2010

One of the main goals of the Second Vatican Council (the 50th anniversary of whose opening will be celebrated in 2012) was the unity of all Christians. Not least among its achievements was the fact that it launched the Catholic Church into the Ecumenical Movement and also paved the way for a global revision of the Church's Code of Canon Law. This article reflects from a Roman Catholic perspective on aspects to do with canon law and ecumenism. It does so in the light of the Council's teaching and reception. Conciliar hermeneutics and questions left open at the Council are considered. In conclusion, the author suggests that greater attention to the Church's charismatic principle and missionary mandate underlined at the Council offers wide scope for continuing exploration among Anglican and Roman Catholic canonists in the cause of unity.
The Historical Background to the Marriage (Wales) Act 2010
Authors: Roberts Nicholas
Published: December 2010

The Marriage (Wales) Act 2010 illustrates that a disestablished church will always occupy an intermediate position between an established church and one which has never been established: the Church in Wales needed an Act to reform its marriage law, whereas paradoxically the Church of England legislated for itself by Measure. The article outlines how the provisions on marriage evolved during the passage of the disestablishment legislation; accepts the validity of contemporaneous arguments based on inconsistency; and outlines previous occasions when the marriage laws of England and of Wales have fallen out of step. It concludes by accepting that the continued establishment of the marriage law in Wales is inconsistent, but that any change is likely to depend on a wholesale reform of marriage law.
The Regulation of Islamic Finance in the United Kingdom
Authors: Ercanbrack Jonathan
Published: December 2010

This article examines the unique risks associated with Islamic financial institutions and the secular state's reticence to directly regulate their religious dimension. It argues that the state's method of regulating the Islamic financial industry ignores special reputational risks associated with the religious and cultural distinctiveness of Islamic banks.
General Synod of the Church of England
Authors: Slack Stephen
Published: December 2010

The single most important piece of legislative business considered by the Synod in 2010 was, of course, the draft legislation relating to women in the episcopate. Having been given First Consideration by the Synod in February 2009, the draft legislation was the subject of detailed consideration by a Revision Committee between May 2009 and April 2010. The Revision Committee received 297 submissions, of which 114 were from individual Synod members or groups including Synod members and others. In consequence, it met on 16 occasions and its report ran to 142 pages.
General Synod of the Church of Ireland
Authors: Davey Michael
Published: December 2010

This year the Church of Ireland General Synod took place in the home of the Metropolitan in Dublin, Christchurch Cathedral. In the more recent past Synod has used the facilities of one of the city's major hotels, facilities which a cathedral could not and would not claim to match. However, the cathedral had in the past been used for many different purposes during its near 1,000-year history and it provided for the Synod an atmosphere wholly unlike any secular conference. One could argue, as did the Dean, that when the Synod is meeting in Dublin Christchurch is its rightful home.
From Work to Consumption. Transatlantic Visions of Individuality in Modern Mass Society
Authors: WIRSCHING ANDREAS
Published: December 2010

This essay deals with the ambiguous and contradictory relationship between labour, consumption and individuality in modern mass culture. This relationship has been conceptualised rather differently in American and European visions of individuality. In recent years, the long-lasting tradition of European (and especially German) scepticism towards the consumer society, which was nourished by conservative, (neo)liberal and Marxist influences, has retreated in favour of a more general acceptance of modern consumerism. While labour has not been replaced as the most important means of economic and cultural participation, the social construction of personal individuality is seen to take place through an ever-increasing multitude of means of consumption. The article analyses this profound process of cultural change and at the same time reflects upon the opportunities and limits of the current scholarly paradigm concerning the consumer society.
Jürgen Kuczynski and the Search for a (Non-Existent) Western Spy Ring in the East German Communist Party in 1953
Authors: STIBBE MATTHEW
Published: December 2010

Jürgen Kuczynski, the East German Marxist intellectual and economic historian, is best known for his numerous publications on labour history. Far less has been written about his role as a leading figure in the German Communist Party in Britain between 1936 and 1944, and his work for the US Strategic Bombing Survey in 1944–5, activities which later came back to haunt him when he was the subject of a major inquiry launched by the Central Party Control Commission in 1953. Using newly available documents in London and Berlin, this article examines the investigation into Kuczynski as a case study for the inter-relationship between party purges, spy scares and the manipulation of individual biographies during one of the most volatile periods of the cold war.
Viability and apoptosis in spermatozoa of transgenic rabbits
Authors: Chrenek P. , Makarevich A.V. , Simon M.
Published: December 2010

The aim of our study was to compare the viability of sperm cells from transgenic (mWAP-hFVIII gene) or non-transgenic (normal) rabbit males as assessed by viability (SYBR-14/PI) and apoptosis (annexin V) tests. These results were evaluated using female conception rates following insemination with the respective sperm samples. No significant differences were found in concentration and motility between transgenic and non-transgenic spermatozoa. Spermatozoa from both transgenic (63.05 ± 20.05%) or non-transgenic (65.75 ± 22.15%) males, stained with SYBR-14 (green), were found to be morphologically normal. In both groups, the highest proportion of annexin V-positive sperm staining was found in the post-acrosomal part of the sperm head (8.66 and 27.53%). The percentage of sperm that stained with SYBR-14/PI or with annexin V/DAPI was correlated with liveborn in transgenic rabbits (R2 = 0.6118 and R2 = 0.2187, respectively) or non-transgenic rabbits (R2 = 0.671 and R2 = 0.3579, respectively). These data indicate that there was no difference in the viability of rabbit transgenic and non-transgenic spermatozoa when determined by both fluorescence assays.
The Mirage of Global Democracy
Authors: De Wilde Jaap
Published: December 2010

The literature about global democracy deals with two different types of democratization: Type 1 is about spreading democracy across sovereign states as the basis for good governance. It focuses on the quality of the state/society-nexus: the balance between coercion, reward and identity. Type 2 is about democratizing world politics as such. In its most concrete expressions it focuses on the relationship between international society (a community of states) and world society (a community of people). The contemporary structure of multilevel governance provides the rationale behind this: national democracies are ineffective in controlling essential centres of power. This implies a need to scale up democracy to global proportions. However, in Type 1 considerations the term democracy often is an empty shell. This blinds observers for checks and balances and types of pluralism in non-democratic states. It also blinds them for misuse of democratic claims in democratic states. Aspiring global democracy in terms of Type 2 ignores that the presence of a central authority is a precondition inherent to the concept of democracy. Democratic theory cannot escape and is consequently caught up in its preconditions of a people (demos) and a government (cratos).
Antislavery Debates: Tides of Historiography in Slavery and Antislavery
Authors: Drescher Seymour
Published: December 2010

This article reviews the changes in historical writing about slavery and the slave trade over the last 50 years.
Society Needs Morality
Authors: Hinde Robert A.
Published: December 2010

Morality must be resurrected in our societies. It must be a morality whose nature and sources are understood and are in keeping with current reality. Hitherto, morality has been seen as closely related to religion. That religious belief is helpful to many is indisputable, but religious narratives, treated literally, are unacceptable to modern minds, and the supposed nature of God, as discussed by sophisticated theologians, is inaccessible to everyman. Morality, based on an understanding of human nature as shaped by culture, offers hope for the future.
Spatial Representations as an Emergent Feature of Perceptual Processing
Authors: Wascher Edmund , Beste C.
Published: December 2010

Spatial selection of relevant information has been proposed to reflect an emergent feature of stimulus processing within an integrated network of perceptual areas. Stimulus-based and intention-based sources of information might converge in a common stage when spatial maps are generated. This approach appears to be inconsistent with the assumption of distinct mechanisms for stimulus-driven and top-down controlled attention. In two experiments, the common ground of stimulus-driven and intention-based attention was tested by means of event-related potentials (ERPs) in the human EEG. In both experiments, the processing of a single transient was compared to the selection of a physically comparable stimulus among distractors. While single transients evoked a spatially sensitive N1, the extraction of relevant information out of a more complex display was reflected in an N2pc. The high similarity of the spatial portion of these two components (Experiment 1), and the replication of this finding for the vertical axis (Experiment 2) indicate that these two ERP components might both reflect the spatial representation of relevant information as derived from the organization of perceptual maps, just at different points in time.
Maternal Perception of Infants’ Expressions of Emotion
Authors: Krippl Martin , Ast-Scheitenberger Stephanie , Bovenschen Ina , Spangler Gottfried
Published: December 2010

In light of Lang’s differentiation of the aversive and the approach system – and assumptions stemming from attachment theory – this study investigates the role of the approach or caregiving system for processing infant emotional stimuli by comparing IAPS pictures, infant pictures, and videos. IAPS pictures, infant pictures, and infant videos of positive, neutral, or negative content were presented to 69 mothers, accompanied by randomized startle probes. The assessment of emotional responses included subjective ratings of valence and arousal, corrugator activity, the startle amplitude, and electrodermal activity. In line with Lang’s original conception, the typical startle response pattern was found for IAPS pictures, whereas no startle modulation was observed for infant pictures. Moreover, the startle amplitudes during negative video scenes depicting crying infants were reduced. The results are discussed with respect to several theoretical and methodological considerations, including Lang’s theory, emotion regulation, opponent process theory, and the parental caregiving system.
Ionospheric convection signatures of the interchange cycle at small interplanetary magnetic field clock angles
Authors: Watanabe Masakazu , Sofko George J. , Yan Xi , McWilliams Kathryn A. , St.‐Maurice Jean‐Pierre , Koustov Alexandre V. , Hussey Glenn C. , Hairston Marc R.
Published: December 2010

The purpose of this paper is to show a “proof of the existence” of the ionospheric situation that is expected for the interchange cycle, during periods of favorable interplanetary magnetic field (IMF) and dipole tilt conditions. To do so, we present three case studies of dayside high‐latitude ionospheric convection that is observed around the equinoxes (near‐zero dipole tilt) and at small IMF clock angles (one θc ∼ −30° event and two θc ∼ 30° events, where θc ≡ Arg(BZ + iBY)), using Super Dual Auroral Radar Network (SuperDARN)/Defense Meteorological Satellite Program (DMSP)/National Oceanic and Atmospheric Administration (NOAA) data in the Northern Hemisphere and, when available, DMSP data in the Southern Hemisphere. The convection pattern exhibits twin reverse cells in both hemispheres, but the constituents of each cell are different. In the Northern Hemisphere, for θc ∼ 30° (θc ∼ −30°), the center of the dawnside (duskside) cell is located poleward of the polar cap boundary, while the center of the duskside (dawnside) cell is located equatorward of the polar cap boundary. For θc ∼ 30°, we confirmed that the above‐mentioned dawn‐dusk relation reverses in the Southern Hemisphere. The north‐south asymmetric behavior of the conjugate reverse cells, on the dawnside and duskside each, is consistent with two independent interchange cycles that result from the coupling of IMF‐lobe reconnection in one hemisphere with lobe‐closed reconnection in the opposite hemisphere.
What determines the maximum sea ice extent in the Sea of Okhotsk? Importance of ocean thermal condition from the Pacific
Authors: Nakanowatari Takuya , Ohshima Kay I. , Nagai Sachiko
Published: December 2010

Previous studies suggested that the interannual variability of the maximum sea ice extent (MSIE) in the Sea of Okhotsk is not explained only by atmospheric conditions. In this study, we examined the effect of the ocean thermal condition on the determination of the MSIE based on observational data. We found that the MSIE is highly correlated with the sea surface temperature (SST) and ocean temperature around the East Kamchatska Current (EKC) in the Pacific in late autumn (November–December). The significant relationship between the MSIE and the SST cannot be fully explained by prevailing atmospheric variabilities. Considering that the inflow of EKC water to the Okhotsk Sea is strengthened in winter, advection of anomalous ocean temperature likely influences the MSIE. A multiple regression model constructed as a function of SST in the EKC and the air temperature at 850 hPa over the upwind region of the Okhotsk Sea in late autumn, which is another determinant factor for the MSIE, significantly improves the prediction skill for the MSIE: 70% of the variance of MSIE can be predicted at the stage of 2 to 3 months before the MSIE season. The SST in the EKC and the upwind air temperature are likely to control the sea ice extent in the northeastern and center to southern parts of the Okhotsk Sea, respectively.
Radiative feedback of dust aerosols on the East Asian dust storms
Authors: Wang Hong , Zhang Xiaoye , Gong Sunling , Chen Yong , Shi Guangyu , Li Wei
Published: December 2010

A new radiative parameterization scheme of dust aerosol has been developed within a mesoscale dust storm (DS) forecasting model to study the direct radiation of dust aerosol by incorporating both online forecasted dust concentrations and the updated dust reflective index. The radiation‐induced temperature variations are fed back online to the model dynamics, resulting in two‐way interactions between meteorology and dust aerosols. For a typical DS of 16–18 April 2006 in East Asia, the study shows that the strong extinction by dust leads to significant changes in the radiation flux from surface to the top of atmosphere, which tends to decrease the air temperature in the lower dust aerosol layers but to increase the air temperature in the upper dust aerosol layers. Consequently, variations of 3‐D temperature fields reduce the cold air in the upper atmosphere, increase the sea level air pressure, decrease surface wind velocity, and eventually weaken the Mongolian cyclones owing to the blocking effects. These changes, in return, have impacts on the emission, transport, and deposition processes of DS. The interactively simulated total dust emission from the ground is reduced by over 50%, and the 72‐hour averaged optical depth of dust aerosols declines by about 33% compared to the one‐way model without dust direct radiative feedback, which indicates strong negative feedback effects. The findings of this study also suggest that online calculation of dust direct radiative effects in a mesoscale dust prediction model may lead to an improvement in the prediction of meteorological elements such as temperature, wind, and pressure during the dust events owing to its improved calculation accuracy of regional radiation budgets.
In‐situ spectroscopic observations of silicate vaporization due to >10 km/s impacts using laser driven projectiles
Authors: Kurosawa Kosuke , Sugita Seiji , Kadono Toshihiko , Shigemori Keisuke , Hironaka Yoichiro , Otani Kazuto , Sano Takayoshi , Shiroshita Akiyuki , Ozaki Norimasa , Miyanishi Kohei , Sakaiya Tatsuhiro , Sekine Yasuhito , Tachibana Shogo , Nakamura Keisuke , Fukuzaki Sho , Ohno Sohsuke , Kodama Ryosuke , Matsui Takafumi
Published: December 2010

We present the results of shock‐induced silicate vaporization experiments using laser driven hypervelocity projectiles. In‐situ spectroscopic observations of shock‐heated quartz and diopside were conducted. We observed both atomic emission lines and blackbody continuum. Because emission lines occur only in a gas phase, this observation indicates that the incipient vaporization of silicates actually occurs at >10 km/s. We estimated the peak‐shock temperatures from the blackbody spectra. The obtained results suggest that the temperature dependence of the isochoric specific heat Cv depends rather strongly on material at extremely high pressures. Such difference in Cv dependence on temperature will influence the impact vaporization efficiency. Thus, investigation on the Cv of the other major silicates is necessary for understanding impact‐related phenomena. Furthermore, the observed high intensity of emission lines shows the possibility that a variety of the thermodynamic variables of expanding silicate vapor can be measured with a higher speed spectrometer.
An empirical model for prediction of geomagnetic storms using initially observed CME parameters at the Sun
Authors: Kim R.‐S. , Cho K.‐S. , Moon Y.‐J. , Dryer M. , Lee J. , Yi Y. , Kim K.‐H. , Wang H. , Park Y.‐D. , Kim Yong Ha
Published: December 2010

In this study, we discuss the general behaviors of geomagnetic storm strength associated with observed parameters of coronal mass ejection (CME) such as speed (V) and earthward direction (D) of CMEs as well as the longitude (L) and magnetic field orientation (M) of overlaying potential fields of the CME source region, and we develop an empirical model to predict geomagnetic storm occurrence with its strength (gauged by the Dst index) in terms of these CME parameters. For this we select 66 halo or partial halo CMEs associated with M‐class and X‐class solar flares, which have clearly identifiable source regions, from 1997 to 2003. After examining how each of these CME parameters correlates with the geoeffectiveness of the CMEs, we find several properties as follows: (1) Parameter D best correlates with storm strength Dst; (2) the majority of geoeffective CMEs have been originated from solar longitude 15°W, and CMEs originated away from this longitude tend to produce weaker storms; (3) correlations between Dst and the CME parameters improve if CMEs are separated into two groups depending on whether their magnetic fields are oriented southward or northward in their source regions. Based on these observations, we present two empirical expressions for Dst in terms of L, V, and D for two groups of CMEs, respectively. This is a new attempt to predict not only the occurrence of geomagnetic storms, but also the storm strength (Dst) solely based on the CME parameters.
Simulation and TWINS observations of the 22 July 2009 storm
Authors: Fok M.‐C. , Buzulukova N. , Chen S.‐H. , Valek P. W. , Goldstein J. , McComas D. J.
Published: December 2010

TWINS is the first mission to perform stereo imaging of the Earth's ring current. The magnetic storm on 22 July 2009 was at the time the largest storm observed since TWINS began routine stereo imaging in June 2008. On 22 July 2009, the Dst dropped to nearly −80 nT at 0700 and 1000 UT. During the main phase, and at the peak of the storm, TWINS 1 and 2 were near apogee and moving between predawn and postdawn local time. The energetic neutral atom (ENA) imagers on the two spacecraft captured the storm intensification and the formation of the partial ring current. The peak of the high‐altitude ENA emissions was seen in the midnight‐to‐dawn local time sector. The development of this storm has been simulated using the comprehensive ring current model (CRCM) to understand and interpret the observed signatures. We perform CRCM runs with constant and time‐varying magnetic field. The model calculations are validated by comparing the simulated ENA and ion flux intensities with TWINS ENA images and in situ ion data from a THEMIS satellite. Simulation with a static magnetic field produces a strong shielding electric field that skews the ion drift trajectories toward dawn. The model's corresponding peak ENA emissions are always more eastward than those in the observed TWINS images. On the other hand, the simulation with a dynamic magnetic field gives better spatial agreement with both ENA and in situ particle data, suggesting that temporal variations of the geomagnetic field exert a significant influence upon global ring current ion dynamics.
Influence of spacecraft outgassing on the exploration of tenuous atmospheres with in situ mass spectrometry
Authors: Schläppi B. , Altwegg K. , Balsiger H. , Hässig M. , Jäckel A. , Wurz P. , Fiethe B. , Rubin M. , Fuselier S. A. , Berthelier J. J. , De Keyser J. , Rème H. , Mall U.
Published: December 2010

In situ mass spectrometry has been a powerful tool in many space missions to investigate atmospheres and exospheres of different bodies in the solar system. Applying new technologies, the mass spectrometers have become increasingly more sensitive. In this study, we show that spacecraft outgassing, which can never be completely prevented, will be the limiting factor in future missions that investigate very tenuous atmospheres and exospheres of moons, asteroids, or comets at large heliocentric distances. The Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA) instrument on the European Space Agency Rosetta mission has monitored spacecraft outgassing for 6 years during the cruise phase with unprecedented instrument sensitivity. It is shown that diffusion of gas from materials and from the spacecraft interior plays an important role in maintaining a relatively permanent thin gas cloud around the spacecraft for many years. The density and composition of this gas cloud depends on location on the spacecraft, maneuvers, and payload activity. The main contaminants are water, which is adsorbed on cold surfaces, and organics from the spacecraft structure, electronics, and insulations. Decomposed lubricant material can give a significant contribution to the total background. Fortunately for Rosetta, outgassing of the spacecraft will play a minor role when the comet is close to perihelion; only in the early phase of the mission the outgassing may be larger than the cometary signature.
Complex states of stress during the normal faulting seismic cycle: Role of midcrustal postseismic creep
Authors: Nüchter Jens‐Alexander , Ellis Susan
Published: December 2010

Numerical models are used to analyze coseismic and postseismic change in the state of stress near the lower tip of a normal fault directly below the brittle‐ductile transition. The models are compared with information obtained from the geological record of exhumed metamorphic rocks regarding the magnitude and the geometry of coseismic stress increase close to the lower fault termination and the mechanisms involved during postseismic stress relaxation. The numerical results predict a drop in differential and fault‐parallel shear stress in the upper crust and a stress increase in the lower crust due to the tapering off in fault slip. The coseismic deformation field in the crust causes significant deflection of the principal stresses from the horizontal and the vertical. During the postseismic period, the recovery of the crustal stress field remains incomplete, even for long recurrence intervals. Instead, the stress field evolves in self‐similar cycles, controlled by repeated earthquake activity. The numerical models show that postseismic viscous creep localized beneath the fault contributes to the recovery of all stress tensor components in the upper crust close to the fault. This result implies that a detailed understanding of the processes and conditions active during postseismic stress relaxation in the middle and lower crust is essential in order to estimate reloading rates in the upper crust surrounding the fault.
Tidal and atmospheric influences on near‐surface turbulence in an estuary
Authors: Orton Philip M. , Zappa Christopher J. , McGillis Wade R.
Published: December 2010

Estuarine near‐surface turbulence is important for transport, mixing, and air‐water exchanges of many important constituents but has rarely been studied in detail. Here, we analyze a unique set of estuarine observations of in situ atmospheric and full water column measurements, estimated air‐sea exchanges, and acoustic measurements of several terms in the turbulent kinetic energy (TKE) budget. Observations from a 5.1 m deep site in the Hudson River estuary include dissipation at 50 cm depth (ɛ50), as well as profiles of TKE, shear production of TKE (P), and net turbulent vertical TKE transport (TD). Regressions suggest that the principal controlling factor for ɛ50 was wind (through the surface shear velocity, U*) and that the surface heat flux and tidal currents played a secondary role. For ebb spring tides, the TKE budget at 50 cm depth was closed within noise levels. Ebbs had high ɛ50 due to local shear production, which nearly balanced ɛ50. Floods had TD approaching P in the upper water column but generally weak near‐surface shear and turbulence. Examining buoyancy fluxes that impact near‐surface stratification and can indirectly control turbulence, solar heat input and tidal straining caused similar buoyancy fluxes on a sunny, calm weather day, promoting ebb tide restratification. Wind‐driven mixing was found to dominate during a fall season storm event, and strong overnight heat loss after the storm helped delay restratification afterward. These results demonstrate the utility of combining detailed air‐sea interaction and physical oceanographic measurements in future estuary studies.
Comparison of monthly means of global total column water vapor retrieved from independent satellite observations
Authors: Mieruch S. , Schröder M. , Noël S. , Schulz J.
Published: December 2010

Two independent data sets of monthly means of total column water vapor (TCWV) have been compared. The first data set is the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT) Satellite Application Facility on Climate Monitoring's (CM‐SAF) Hamburg Ocean Atmosphere Parameters and Fluxes from Satellite Data (HOAPS) product, which is based on passive microwave observations from the Special Sensor Microwave/Imager (SSM/I). It is available over oceans only and includes the TCWV also from cloudy scenes. The second one relies on Global Ozone Monitoring Experiment/Scanning Imaging Absorption Spectrometer for Atmospheric Cartography (GOME/SCIAMACHY) measurements, which are carried out in the visible part of the solar spectrum and present a partly cloud corrected climatology that is available over land and ocean. The comparison is performed for the period 1996 to 2005 for ice‐free ocean areas. This comparison helps to analyze the potential of the two data sets to provide an independent merged TCWV data set for all surface types in the future. A systematic difference or bias is observed between both data sets, with lower TCWV for GOME/SCIAMACHY. The dominating cause (80–90%) for the difference in monthly averages is the cloud correction approach used within the GOME/SCIAMACHY retrieval scheme. We show that the bias contains a pronounced seasonal component and relies on cloud properties such as the cloud water path.
Sensitivity of the global distribution of cirrus ice crystal concentration to heterogeneous freezing
Authors: Barahona D. , Rodriguez J. , Nenes A.
Published: December 2010

This study presents the sensitivity of global ice crystal number concentration, Nc, to the parameterization of heterogeneous ice nuclei (IN). Simulations are carried out with the NASA Global Modeling Initiative chemical and transport model coupled to an analytical ice microphysics parameterization. Heterogeneous freezing is described using nucleation spectra derived from theoretical considerations and empirical data for dust, black carbon, ammonium sulfate, and glassy aerosol as IN precursors. When competition between homogeneous and heterogeneous freezing is considered, global mean Nc vary by up to a factor of twenty depending on the heterogeneous freezing spectrum used. IN effects on Nc strongly depend on dust and black carbon concentrations and are strongest under conditions of weak updraft and high temperature. Regardless of the heterogeneous spectrum used, dust is an important contributor of IN over large regions of the Northern Hemisphere. Black carbon however exhibits appreciable effects on Nc when the freezing fraction is greater than 1%. Compared to in situ observations, Nc is overpredicted at temperatures below 205 K, even if a fraction of liquid aerosol is allowed to act as glassy IN. Assuming that cirrus formation is forced by weak updraft addressed this overprediction but promoted heterogeneous freezing effects to the point where homogeneous freezing is inhibited for IN concentrations as low as 1 L−1. Chemistry and dynamics must be considered to explain cirrus characteristics at low temperature. Only cloud formation scenarios where competition between homogeneous and heterogeneous freezing is the dominant feature would result in maximum supersaturation levels consistent with observations.