bluuebunny/crossref_metadata_2025 huggingface dataset:
Determination of Trace Amounts of Lead Using the Flotation-spectrophotometric method
Authors: Shiri Sabah , Delpisheh Ali , Haeri Ali , Poornajaf Abdolhossein , Golzadeh Babak , Shiri Sina
Published: December 2010

The present study describes a simple and highly selective method for separation, preconcentration and spectrophotometric determination of extremely low concentrations of lead. It is based on flotation of a complex of Pb2+ ions and Alizarin yellow between aqueous and n-hexane interface at pH = 6. The proposed procedure is also applied for determination of lead in both tap water and prepared sea water samples. Beer's Law was obeyed over the concentration range of 3.86 × 10−8 To 8.20 × 10−7 molL−1 (8-170 ngmL−1) with an apparent molar absorptivity of 1.33 × 106 molL−1 cm−1 for a 100 mL aliquot of the water sample. The detection limit (n = 10) was 8.7 × 10−9 molL−1 (1.0 ngmL−1) and the Relative standard deviation (R.S.D), (n = 10) for 7.2 × 10−7 molL−1 (150 ngmL−1) of Pb (II) was 4.36%. A notable advantage of the method is that the determination of Pb (II) is free from the interference of almost all cations and ions found in the environment and waste water samples. The determination of Pb (II) in tap and synthetic seawater samples was also carried out by the present method. The results were satisfactorily comparable so that the applicability of the proposed method was confirmed to the real samples.
The pro-BNP Serum Level and Echocardiographic Tissue Doppler Abnormalities in Patients with Beta Thalassemia Major
Authors: Garadah Taysir S. , Mahdi Najat , Kassab Salah , Shoroqi Isa Al , Abu-Taleb Ahmed , Jamsheer Anwer
Published: December 2010

Background

Doppler echocardiographic studies of the left ventricle (LV) function in patients with β-Thalassemia Major (β-TM) had shown different patterns of systolic and diastolic dysfunctions associated with abnormal serum brain natriuretic peptide (BNP).

Aim

This cross-sectional study was designed to study the LV systolic and diastolic functions and correlate that with serum level of N-terminal pro brain natriuretic hormone (NT- pro BNP) in patients with β-TM using Pulsed Doppler (PD) and Tissue Doppler (TD) echocardiography.

Methods

The study was conducted on patients with β-TM (n = 38, age 15.7 ± 8.9 years) and compared with an age-matched controls (n = 38, age 15.9 ± 8.9 years). In all participants, PD and TD echocardiography were performed and blood samples were withdrawn for measuring the serum level of NT-pro BNP, ferritin, and alanine transaminase.

Results

Patients with β-TM compared with controls, have thicker LV septal wall index (0.65 ± 0.26 vs. 0.44 ± 0.21 cm, P < 0.001), posterior wall index (0.65 ± 0.23 vs. 0.43 ± 0.21 cm, P < 0.01), and larger LVEDD index (4.35 ± 0.69 vs.3.88 ± 0.153 mm, P < 0.001). In addition, β-TM patients have higher transmitral E wave velocity (E) (70.818 ± 10.139 vs. 57.532 ± 10.139, p = 0.027) and E/A ratio (1.54 ± 0.17 vs. 1.23 ± 0.19, P < 0.01) and shorter deceleration time (DT) (160.13 ± 13.3 vs. 170.50 ± 19.20 m sec, P < 0.01). Furthermore, the ratio of transmitral E wave velocity to the tissue Doppler E wave at the basal septal mitral annulus (E/Em–) was significantly higher in β-TM group (19.6 ± 2.81 vs. 13.868 ± 1.41, P < 0.05). The tissue doppler systolic wave (Sm) velocity and the early diastolic wave (Em) were significantly lower in β-TM group compared to controls (Sm: 4.82 ± 1.2 vs. 6.22 ± 2.1 mm/sec, P < 0.05; Em: 3.51 ± 2.7 vs. 4.12 ± 2.5 mm/sec P < 0.05, respectively). The tricuspid valve velocity was significantly higher in β-TM patients compared with controls (2.993 ± 0.569 vs. 1.93 ± 0.471 m/sec, respectively, P < 0.01). The mean serum NT pro-BNP in β-TM was significantly higher compared with controls (37.6 ± 14.73 vs. 5.5 ± 5.4pg/ml, P < 0.05). The left ventricle ejection fraction (EF%) and fractional shortening (FS%) were not significantly different between both groups.

Conclusion

We conclude that patients with β-TM had a significantly higher serum level of NT-pro BNP that is positively correlated with the E/Em ratio on tissue Doppler. Furthermore, we confirm our previous findings that patients with β-TM exhibit LV diastolic pattern on echocardiogram suggestive of restrictive type with well preserved left ventricle systolic function.
Attributing and quantifying European carbon monoxide sources affecting the Eastern Mediterranean: a combined satellite, modelling, and synoptic analysis study
Authors: Drori R. , Dayan U. , Edwards D. P. , Emmons L. K. , Erlick C.
Published: December 2010

Abstract. European pollutants are known to affect the Eastern Mediterranean (EM). However, there has been no previous study explicitly locating the European sources, characterizing their transport pathways, and quantifying their contribution to local concentrations in the EM. In the current study, spatially tagged carbon monoxide was used as a tracer for pollutant transport from Europe to the EM over five consecutive years (2003–2007) using the global chemical transport model MOZART-4. The model results were compared against NOAA/GMD ground station data and remotely sensed data from the Terra/MOPITT satellite and found to agree well. European anthropogenic emissions were found to significantly influence EM surface concentrations, while European biomass burning (BB) emissions were found to have only a small impact on EM surface concentrations. Over the five simulated years, only two European biomass burning episodes contributed more than 10 ppb to surface CO concentrations in the EM. CO enhancement in the EM during the summer was attributed to synoptic conditions prone to favorable transport from Turkey and Eastern Europe towards the EM rather than increased emissions. We attribute the apparently misleading association between CO emitted from European BB and CO enhancements over the EM to typical summer synoptic conditions caused by the lingering of an anticyclone positioned over the Western and Central Mediterranean Basin that lead to forest fires in the area. Combined with a barometric trough over the eastern part of the Mediterranean Basin, this generates a prevailing transport of air masses from Eastern Europe to the EM shore.
Modeling chemistry in and above snow at Summit, Greenland – Part 1: Model description and results
Authors: Thomas J. L. , Stutz J. , Lefer B. , Huey L. G. , Toyota K. , Dibb J. E. , von Glasow R.
Published: December 2010

Abstract. Sun-lit snow is increasingly recognized as a chemical reactor that plays an active role in uptake, transformation, and release of atmospheric trace gases. Snow is known to influence boundary layer air on a local scale, and given the large global surface coverage of snow may also be significant on regional and global scales. We present a new detailed one-dimensional snow chemistry module that has been coupled to the 1-D atmospheric boundary layer model MISTRA, we refer to the coupled model as MISTRA-SNOW. The new 1-D snow module, which is dynamically coupled to the overlaying atmospheric model, includes heat transport in the snowpack, molecular diffusion, and wind pumping of gases in the interstitial air. The model includes gas phase photochemistry and chemical reactions both in the interstitial air and the atmosphere. Heterogeneous and multiphase chemistry on atmospheric aerosol is considered explicitly. The chemical interaction of interstitial air with snow grains is simulated assuming chemistry in a liquid (aqueous) layer on the grain surface. The model was used to investigate snow as the source of nitrogen oxides (NOx) and gas phase reactive bromine in the atmospheric boundary layer in the remote snow covered Arctic (over the Greenland ice sheet) as well as to investigate the link between halogen cycling and ozone depletion that has been observed in interstitial air. The model is validated using data taken 10 June–13 June, 2008 as part of the Greenland Summit Halogen-HOx experiment (GSHOX). The model predicts that reactions involving bromide and nitrate impurities in the surface snow at Summit can sustain atmospheric NO and BrO mixing ratios measured at Summit during this period.
First measurements of electron vorticity in the foreshock and solar wind
Authors: Gurgiolo C. , Goldstein M. L. , Viñas A. F. , Fazakerley A. N.
Published: December 2010

Abstract. We describe the methodology used to set up and compute spatial derivatives of the electron moments using data acquired by the Plasma Electron And Current Experiment (PEACE) from the four Cluster spacecraft. The results are used to investigate electron vorticity in the foreshock. We find that much of the measured vorticity, under nominal conditions, appears to be caused by changes in the flow direction of the return (either reflected or leakage from the magnetosheath) and strahl electron populations as they couple to changes in the magnetic field orientation. This in turn results in deflections in the total bulk velocity producing the measured vorticity.
A diagnostic study of monsoon energetics for two contrasting years
Authors: Ramakrishna S. S. V. S. , Brahmananda Rao V. , Sravani A. , Vijaya Saradhi N. , Harikishan G.
Published: December 2010

Abstract. In the present study we made an attempt to explain the behavior of the southwest monsoon for two contrasting years, from the view point of energetics. As a test case we selected 2002 and 2003, which were weak and strong monsoon years, respectively, based on rainfall. The energy terms Kψ, Kχ and APE and the conversion terms f∇ψ. ∇χ, −ω'T' are calculated at 850 hPa level and also vertically integrated from 1000 hPa to 100 hPa. The results indicate that, the year of high energy (both KΨ, Kχ) i.e. 2002, does not give a good amount of rainfall compared to the good year i.e. 2003. The break period during the year 2002 has been clearly explained using the block diagrams. Periods of highest rainfall coincide with the positive conversions of f∇ψ. ∇χ and −ω'T'. Vertically integrated moisture fluxes during the break period of 2002, 2003 are also analyzed. The main reservoirs (sources and sinks) for the monsoon energy are also identified using block diagrams. Negative correlation between daily rainfall and energy terms in the year 2002 indicates its unusual behavior both in terms of energetics as well as precipitation. Positive correlations in the year 2003 represent strong monsoonal behavior. We calculated the climatology of the total kinetic energy at 850 hPa, vertically integrated (1000–100 hPa) for 30 years (1980–2009) and rainfall for 103 years (1901–2003) which clearly indicates that the monsoon is indeed a season of high energy for the South Asian region. Also the east- west direct thermal circulations are strongly related to the good and bad monsoon years.
Dust deposition: iron source or sink? A case study
Authors: Ye Y. , Wagener T. , Völker C. , Guieu C. , Wolf-Gladrow D. A.
Published: December 2010

Abstract. A significant decrease of dissolved iron (DFe) concentration has been observed after dust addition into mesocosms during the DUst experiment in a low Nutrient low chlorophyll Ecosystem (DUNE), carried out in the summer of 2008. To understand the processes regulating the observed DFe variation, we simulated the experiment by a one-dimensional model of the Fe biogeochemical cycle, coupled with a simple ecosystem model. Different size classes of particles and particle aggregation are taken into account to describe the particle dynamics. DFe concentration is regulated in the model by dissolution from dust particles and adsorption onto particle surfaces, biological uptake, and photochemical mobilisation of particulate iron. The model reproduces the observed DFe decrease after dust addition well, choosing particle adsorption rates of 30, 150 and 750 m3 kg−1 d−1 for particles of different size classes. These adsorption rates range between the measured adsorption rates of soluble iron and those of colloidal iron, indicating both processes controlling the DFe removal during the experiment. Sensitivity studies reveal that initial DFe concentration before dust addition was crucial for the net impact of dust addition on DFe during the DUNE experiment. From the balance between sinks and sources of DFe, a critical DFe concentration, above which dust deposition acts as a net sink of DFe, rather than a source, has been estimated for the DUNE experiment. Taking into account the role of excess iron binding ligands, this concept of a critical DFe concentration might be applied to explain the short-term variability of DFe after natural dust deposition.
Terrestrial mollusc records from Xifeng and Luochuan L9 loess strata and their implications for paleoclimatic evolution in the Chinese Loess Plateau during marine oxygen isotope stages 24–22
Authors: Wu B. , Wu N. Q.
Published: December 2010

Abstract. Marine Isotope Stages 24–22 is a key period of the Mid-Pleistocene Transition, however, its climate variability is still unclear. The coarse-grained loess unit L9, one of the most prominent units in the Chinese loess stratigraphy, yields a high potential terrestrial record of paleoclimatic and paleoenvironmental changes during this period. In this study, two high-resolution terrestrial mollusc records of L9 loess strata from the Xifeng and Luochuan sequences in the Chinese Loess Plateau were analyzed. Our mollusc results show that the MIS 24, the early and late parts of MIS 22 were dominated by cold and dry climate. Relatively mild-humid climate occurred in MIS 23 and the middle part of MIS 22. The climatic conditions at Xifeng region were cooler and more unstable compared to Luochuan region. A comparison of mollusc species composition and other proxies of L9 strata (MIS 24–22) with those of L1 loess units (MIS 4–2) reveals that the L9 loess was not deposited under the most severe glacial conditions in Quaternary climate history as suggested by previous studies. Our study shows that climatic conditions in the Loess Plateau during the L9 loess forming period were like that of gentle glacials (MIS 24 and MIS 22) and interglacial (MIS 23), as suggested by marine δ18O record. Three cooling fluctuations occurred at ~940–923 ka, 905–895 ka and 885–875 ka, which might be hints of the global "900 ka cooling event". The "900-ka event" in the Loess Plateau seems not a simple long glaciation but a complex of several climatic fluctuations superposed on a general cooling trend. The uplift of Tibetan Plateau and its adjacent regions during this period resulted in a rapid increase in source materials of desert and loess and an enhancement of winter monsoon, which would have amplified the effects of cooling climate on dust production and transport during MIS 24–22, as indicated by increased grain size and mass accumulation rate of L9 loess.
Relaxation on the Ismetpasa segment of the North Anatolian Fault after the Golcuk Mw = 7.4 and Duzce Mw = 7.2 shocks
Authors: Kutoglu H. S. , Akcin H. , Gundogdu O. , Gormus K. S. , Koksal E.
Published: December 2010

Abstract. The Ismetpasa segment of the North Anatolian Fault (NAF) is a rare place where aseismic fault slip (creep) has been observed. Its creep behaviour has been monitored using different observation methods since the 1950s. The findings obtained from the studies until 1990s showed that the creep rate exponentially decreased before the major shocks in 1999, Golcuk (Mw = 7.4) and Duzce (Mw = 7.2). After these shocks, three GPS periods observation in 2002, 2007 and 2008 were carried out on the geodetic network established around the segment. The evaluations of these observations showed that the creep behaviour relaxed after the major earthquakes. This result demonstrates that the creep behaviour of the Ismetpasa segment might be a warning before future major earthquakes.
Does insect folivory vary with latitude among temperate deciduous forests?
Authors: Zhang Yangjian , Adams Jonathan , Zhao Dehai
Published: December 2010

There is a widespread belief that warmer climate forests suffer more folivory, as a proportion of leaf area, than cooler climate forests. However, there is a need for closely standardized studies to test this assumption. In this study, we estimated total folivory as percentage area damaged in freshly fallen, undecayed autumn leaves from the forest floor during the lifetime of deciduous tree leaves, using scanner‐linked software. Over a period of 2 years, 154 samples were taken at 96 forested localities in eastern North America, spanning 17° of latitude. In terms of percentage area damage per leaf, the results in both years sampled suggest that there is significantly more damage in warmer, lower latitude areas of eastern North America. The decreasing folivory rate is higher in northern than in southern regions. The observations of a latitudinal trend may suggest that ‘biotic’ interaction is indeed more important in warmer temperate climates compared to cool temperate climates.
COX‐2 Inhibition and Inhibition of Cytosolic Phospholipase A2 Increase CD36 Expression and Foam Cell Formation in THP‐1 Cells
Authors: Anwar Kamran , Voloshyna Iryna , Littlefield Michael J. , Carsons Steven E. , Wirkowski Peter A. , Jaber Nadia L. , Sohn Andrew , Eapen Sajan , Reiss Allison B.
Published: December 2010

Cardiovascular safety of cyclooxygenase (COX)‐2‐selective inhibitors and nonselective nonsteroidal anti‐inflammatory drugs (NSAIDs) is of worldwide concern. COX‐2 inhibitors and NSAIDs act by inhibiting arachidonic acid metabolism to prostaglandins. They confer a cardiovascular hazard manifested as an elevated risk of myocardial infarction. Mechanisms underlying these cardiovascular effects are uncertain. Here we determine whether interference with cytosolic phospholipase A2 (cPLA‐2) or COX‐2 through pharmacologic blockade or silencing RNA impacts expression of scavenger receptor CD36 and scavenger receptor A, both involved in cholesterol uptake in monocytes and macrophages. THP‐1 human monocytes and human peripheral blood mononuclear cells were exposed to celecoxib, a COX‐2 selective inhibitor currently in clinical use, and to arachidonyl trifluoromethyl ketone (AACOCF3), an arachidonic acid analog that selectively inhibits cPLA‐2. Celecoxib and AACOCF3 each upregulated expression of CD36, but not scavenger receptor A, as determined by quantitative PCR and immunoblotting. Silencing of cPLA‐2 or COX‐2 had comparable effects to pharmacologic treatments. Oil red O staining revealed a profound increase in foam cell transformation of THP‐1 macrophages exposed to either celecoxib or AACOCF3 (both 25 μM), supporting a role for the COX pathway in maintaining macrophage cholesterol homeostasis. Demonstration of disrupted cholesterol balance by AACOCF3 and celecoxib provides further evidence of the possible mechanism by which COX inhibition may promote lipid overload leading to atheromatous lesion formation and increased cardiovascular events.
Aerobic Training in Rats Increases Skeletal Muscle Sphingomyelinase and Serine Palmitoyltransferase Activity, While Decreasing Ceramidase Activity
Authors: Błachnio‐Zabielska Agnieszka , Zabielski Piotr , Baranowski Marcin , Gorski Jan
Published: December 2010

Sphingolipids are important components of cell membranes that may also serve as cell signaling molecules; ceramide plays a central role in sphingolipid metabolism. The aim of this study was to examine the effect of 5 weeks of aerobic training on key enzymes and intermediates of ceramide metabolism in skeletal muscles. The experiments were carried out on rats divided into two groups: (1) sedentary and (2) trained for 5 weeks (on a treadmill). The activity of serine palmitoyltransferase (SPT), neutral and acid sphingomyelinase (nSMase and aSMase), neutral and alkaline ceramidases (nCDase and alCDase) and the content of sphingolipids was determined in three types of skeletal muscle. We also measured the fasting plasma insulin and glucose concentration for calculating HOMA‐IR (homeostasis model assessment) for estimating insulin resistance. We found that the activities of aSMase and SPT increase in muscle in the trained group. These changes were followed by elevation in the content of sphinganine. The activities of both isoforms of ceramidase were reduced in muscle in the trained group. Although the activities of SPT and SMases increased and the activity of CDases decreased, the ceramide content did not change in any of the studied muscle. Although ceramide level did not change, we noticed increased insulin sensitivity in trained animals. It is concluded that training affects the activity of key enzymes of ceramide metabolism but also activates other metabolic pathways which affect ceramide metabolism in skeletal muscles.
Neural Plasticity After Acquired Brain Injury: Evidence from Functional Neuroimaging
Authors: Chen Haiwen , Epstein Jane , Stern Emily
Published: December 2010

The reorganization of the adult central nervous system after damage is a relatively new area of investigation. Neuroimaging methods, such as functional magnetic resonance imaging, diffusion tensor imaging, and positron emission tomography, have the ability to identify, in vivo, some of the processes involved in these neuroplastic changes and can help with diagnosis, prognosis, and potentially treatment approaches. In this article, traumatic brain injury and stroke are used as examples in which neural plasticity plays an important role in recovery. Basic concepts related to brain remodeling, including spontaneous reorganization and training‐induced recovery, as well as characteristics of reorganization in successful recovery, are reviewed. The microscopic and molecular mechanisms that underlie neural plasticity and neurogenesis are briefly described. Finally, exciting future directions for the evaluation, diagnosis, and treatment of severe brain injury are explored, with an emphasis on how neuroimaging can help to inform these new approaches.
Role of Low‐Level Laser Therapy in Neurorehabilitation
Authors: Hashmi Javad T. , Huang Ying‐Ying , Osmani Bushra Z. , Sharma Sulbha K. , Naeser Margaret A. , Hamblin Michael R.
Published: December 2010

This year marks the 50th anniversary of the discovery of the laser. The development of lasers for medical use, which became known as low‐level laser therapy (LLLT) or photobiomodulation, followed in 1967. In recent years, LLLT has become an increasingly mainstream modality, especially in the areas of physical medicine and rehabilitation. At first used mainly for wound healing and pain relief, the medical applications of LLLT have broadened to include diseases such as stroke, myocardial infarction, and degenerative or traumatic brain disorders. This review will cover the mechanisms of LLLT that operate both on a cellular and a tissue level. Mitochondria are thought to be the principal photoreceptors, and increased adenosine triphosphate, reactive oxygen species, intracellular calcium, and release of nitric oxide are the initial events. Activation of transcription factors then leads to expression of many protective, anti‐apoptotic, anti‐oxidant, and pro‐proliferation gene products. Animal studies and human clinical trials of LLLT for indications with relevance to neurology, such as stroke, traumatic brain injury, degenerative brain disease, spinal cord injury, and peripheral nerve regeneration, will be covered.
Assessment and Modulation of Neural Plasticity in Rehabilitation With Transcranial Magnetic Stimulation
Authors: Bashir Shahid , Mizrahi Ilan , Weaver Kayleen , Fregni Felipe , Pascual‐Leone Alvaro
Published: December 2010

Despite intensive efforts to improve outcomes after acquired brain injury, functional recovery is often limited. One reason for this limitation is the challenge in assessing and guiding plasticity after brain injury. In this context, transcranial magnetic stimulation (TMS), a noninvasive tool of brain stimulation, could play a major role. TMS has been shown to be a reliable tool for measuring plastic changes in the motor cortex associated with interventions in the motor system, such as motor training and motor cortex stimulation. In addition, as illustrated by the experience in promoting recovery from stroke, TMS is a promising therapeutic tool to minimize motor, speech, cognitive, and mood deficits. In this review, we will focus on stroke to discuss how TMS can provide insights into the mechanisms of neurologic recovery and how it can be used for measurement and modulation of plasticity after an acquired brain insult.
Die Fähigkeiten von Athleten verändern deren Wahrnehmung von Handlungen
Authors: Shiffrar Maggie , Heinen Thomas
Published: December 2010

Zusammenfassung. Wie nimmt das menschliche visuelle System Handlungen wahr? – Traditionelle Modelle der visuellen Wahrnehmung nehmen an, dass bei allen Beobachtern die gleichen visuellen Prozesse der Analyse von visuellen Stimuli unterschiedlicher Art zu Grunde liegen. Dieser theoretische Ansatz sagt vorher, dass unterschiedliche Personen Gegenstände und Handlungen in gleicher Art und Weise wahrnehmen, unabhängig davon, ob sich ihr Bewegungssystem beispielsweise durch krankheitsbedingte Veränderungen oder Trainingsanpassungen unterscheidet. Demgegenüber nehmen Theorien der embodied perception an, dass individuelle Fähigkeiten des Beobachters die visuelle Wahrnehmung beeinflussen. Ausgehend von diesem Ansatz ist das, was man sieht, dadurch bestimmt, was man physisch tun (kann). Menschliche Bewegung wird dabei als eine spezielle Kategorie von visuellen Bewegungsreizen angesehen, da es die einzige Bewegungsart ist, welche der Mensch ausführen und wahrnehmen kann. Der vorliegende Artikel gibt einen Überblick über aktuelle neuro- und verhaltenswissenschaftliche Befunde zur visuellen Wahrnehmung menschlicher Bewegung unter besonderer Berücksichtigung der Rolle des motorischen Systems. Dabei wird auf die Wahrnehmung von Athleten eingegangen, da diese Personengruppe über spezifische motorische und visuelle Fähigkeiten verfügt, welche den Erklärungswert traditioneller Theorien der visuellen Wahrnehmung kritisch hinterfragen.
„Embodied Cognition”
Authors: Beilock Sian L. , Hohmann Tanja
Published: December 2010

Zusammenfassung. Im Gegensatz zu traditionellen Ansätzen, in denen das Gehirn als abstrakter Informationsprozessor gesehen wurde, gehen aktuelle Theorien davon aus, dass unsere Repräsentationen von Objekten und Ereignissen in einem engen Zusammenhang mit den damit verbundenen Handlungsmöglichkeiten stehen (sog. „embodied cognition”). Unsere Kognitionen, d. h. wie wir Objekte oder auch Ereignisse in der Umwelt repräsentieren, hängen demnach von den eigenen Handlungserfahrungen ab. Das Ziel dieses Übersichtsartikels besteht darin, aktuelle Ergebnisse sowohl aus der verhaltens- als auch der neurowissenschaftlichen Forschung zu dokumentieren. Diese zeigen, dass sensomotorische Erfahrungen die Kognitionen beeinflussen. Bewegungserfahrung spielt deshalb eine zentrale Rolle innerhalb des „embodied cognition Ansatzes”. Aus diesem Grund erscheint es sinnvoll, dass Forscher aus den Bereichen der Kognitions- und Neurowissenschaften sowie der Sportpsychologie und Motorikforschung zusammenarbeiten, um die Theorien zu „embodied cognition” weiter voran zu bringen.
Mesosphere‐stratosphere‐troposphere radar observations of characteristics of lower atmospheric high‐frequency gravity waves passing through the tropical easterly jet
Authors: Ramkumar T. K. , Niranjan kumar K. , Mehta Sanjay K.
Published: December 2010

In this study, we have examined the characteristics of high‐frequency gravity waves (5–50 min periodicity) over a tropical region using the mesosphere‐stratosphere‐troposphere (MST) radar installed at Gadanki (13.5°N, 79.2°E), India. The MST radar (53 MHz) was operated continuously for ∼15.5 h during 1700–0840 LT on 2–3 June 2005. During this period, a strong unstable wind shear region existed above the tropical easterly jet at the height of tropopause. This has provided an excellent opportunity to study the characteristics of internal atmospheric high‐frequency (∼15–40 min periodicity) gravity waves, generated in the boundary layer and passing through the shear layer. The study reveals the generation of higher‐frequency (5–15 min periodicity) gravity waves from this strong shear region and their vertical propagation both below up to a few kilometers and above the shear layer (∼0.5 km thick). These waves showed upward propagation even above 20 km in the lower stratosphere, indicating that unstable shear layers are the important source of momentum and energy fluxes that contribute significantly to the middle atmospheric dynamics in terms of gravity waves. Further, a close association was also observed between the dissipating gravity waves and the distinctly enhanced signal‐to‐noise ratio and Doppler spectral width of the MST radar echoes. The present observation of radiation of high‐frequency gravity waves that propagate vertically upward from a strong wind shear region located immediately below a highly stratified layer is in accordance with the “direct mechanism” explained by nonlinear numerical simulation studies. For the first time, the present study illustrates the existence of layers of polarized refractive index structures in the heights of 10–15 km.
Improved categorical winter precipitation forecasts through multimodel combinations of coupled GCMs
Authors: Devineni Naresh , Sankarasubramanian A.
Published: December 2010

A new approach to combine precipitation forecasts from multiple models is evaluated by analyzing the skill of the candidate models contingent on the forecasted predictor(s) state. Using five leading coupled GCMs (CGCMs) from the ENSEMBLES project, we develop multimodel precipitation forecasts over the continental United States (U.S) by considering the forecasted Nino3.4 from each CGCM as the conditioning variable. The performance of multimodel forecasts is compared with individual models based on rank probability skill score and reliability diagram. The study clearly shows that multimodel forecasts perform better than individual models and among all multimodels, multimodel combination conditional on Nino3.4 perform better with more grid points having the highest rank probability skill score. The proposed algorithm also depends on the number of years of forecasts available for calibration. The main advantage in using this algorithm for multimodel combination is that it assigns higher weights for climatology and lower weights for CGCM if the skill of a CGCM is poor under ENSO conditions. Thus, combining multiple models based on their skill in predicting under a given predictor state(s) provides an attractive strategy to develop improved climate forecasts.
Compositions of subsurface ices at the Mars Phoenix landing site
Authors: Cull Selby , Arvidson Raymond E. , Mellon Michael T. , Skemer Philip , Shaw Amy , Morris Richard V.
Published: December 2010

NASA's Phoenix Lander uncovered two types of ice at its 2008 landing site on the northern plains of Mars: a brighter, slab‐like ice that broke during Robotic Arm operations; and a darker icy deposit. Spectra from the Phoenix Surface Stereo Imager (SSI) are used to demonstrate that the brighter material consists of nearly pure water ice, which probably formed by migration and freezing of liquid water. The darker icy material consists of ∼30 ± 20 wt% ice, with the remainder composed of fine‐grained soil, indicating that it probably formed as pore ice. These two types of ice represent two different emplacement mechanisms and periods of deposition.
Aerosol size confines climate response to volcanic super‐eruptions
Authors: Timmreck Claudia , Graf Hans‐F. , Lorenz Stephan J. , Niemeier Ulrike , Zanchettin Davide , Matei Daniela , Jungclaus Johann H. , Crowley Thomas J.
Published: December 2010

Extremely large volcanic eruptions have been linked to global climate change, biotic turnover, and, for the Younger Toba Tuff (YTT) eruption 74,000 years ago, near‐extinction of modern humans. One of the largest uncertainties of the climate effects involves evolution and growth of aerosol particles. A huge atmospheric concentration of sulfate causes higher collision rates, larger particle sizes, and rapid fall out, which in turn greatly affects radiative feedbacks. We address this key process by incorporating the effects of aerosol microphysical processes into an Earth System Model. The temperature response is shorter (9–10 years) and three times weaker (−3.5 K at maximum globally) than estimated before, although cooling could still have reached −12 K in some midlatitude continental regions after one year. The smaller response, plus its geographic patchiness, suggests that most biota may have escaped threshold extinction pressures from the eruption.
Abrupt equatorial wave‐induced cooling of the Atlantic cold tongue in 2009
Authors: Foltz Gregory R. , McPhaden Michael J.
Published: December 2010

Between May and August 2009 sea surface temperatures (SSTs) in the eastern equatorial Atlantic dropped 5°C, from 1°C above normal to 1°C below normal. The magnitude of this cooling is unprecedented since satellite SST measurements began in 1982. In this study, observations and a linear equatorial wave model are used to examine the causes of the sharp decrease in SST. It is found that the anomalous cooling along the equator can be traced to an anomalous meridional gradient of SST and associated northwesterly anomalous winds that developed in the equatorial Atlantic the preceding spring. The anomalous winds forced upwelling equatorial Rossby waves that propagated westward during boreal spring and reflected at the western boundary into upwelling Kelvin waves during late spring and summer. The upwelling Kelvin waves propagated eastward along the equator, anomalously decreasing sea level and SST during May–August.
Nighttime medium‐scale traveling ionospheric disturbances at low geomagnetic latitudes
Authors: Makela J. J. , Miller E. S. , Talaat E. R.
Published: December 2010

Nighttime medium‐scale traveling ionospheric disturbances (MSTIDs) are a commonly‐observed structure in the middle latitude ionosphere during the months surrounding the solstices and low solar flux conditions. MSTIDs consist of one or more narrow bands exhibiting uplift in F‐region electron density which are elongated from northwest to southeast in the northern hemisphere and southwest to northeast in the southern hemisphere. These electrified structures propagate westward and toward the equator in a direction perpendicular to their long dimension. Previously, this type of MSTID was not thought to occur at magnetic latitudes equatorward of the equatorial anomalies, or approximately ±15° geomagnetic latitude. Here, we present observational evidence from a field‐aligned narrowfield imaging system of MSTIDs existing very close to the magnetic equator. We discuss the implications of this observation in terms of the development and propagation of MSTIDs.
Observations of X‐ray and EUV fluxes during X‐class solar flares and response of upper ionosphere
Authors: Mahajan K. K. , Lodhi Neelesh K. , Upadhayaya Arun K.
Published: December 2010

Most studies dealing with solar flare effects in the upper ionosphere, where ionization is caused by EUV photons, have been based upon X‐ray fluxes measured by the SOLRAD and GOES series of satellites. To check the validity of such studies, we compare simultaneous observations of GOES X‐ray fluxes and SOHO EUV fluxes for 10 X‐class solar flares which occurred during the maximum phase of sunspot cycle 23. These include the greatest flare of 4 November 2003, the fourth greatest flare of 28 October 2003 and the 14 July 2000 Bastille Day flare. We find that the peak intensities of the X‐ray and EUV fluxes for these flares are poorly correlated, and this poor correlation is again seen when larger data containing 70 X‐class flares, which occurred during the period January 1996 to December 2006, are examined. However, this correlation improves vastly when the central meridian distance (CMD) of the flare location is taken into account. We also study the response of the upper ionosphere to these fluxes by using the midday total electron content (TEC), observed for these flares by Liu et al. (2006). We find that peak enhancement in TEC is highly correlated with peak enhancement in EUV flux. The correlation, though poor with the X‐ray flux, improves greatly when the CMD of flare location is considered.
EMIC wave activity during geomagnetic storm and nonstorm periods: CRRES results
Authors: Halford A. J. , Fraser B. J. , Morley S. K.
Published: December 2010

Electromagnetic ion cyclotron (EMIC) waves have been observed during geomagnetic storms and are thought to contribute to ring current and radiation belt particle loss during the main phase. Ground‐based storm time studies alternatively observe the majority of storm time Pc1‐2 pulsations during the recovery phase. In this study we look at the occurrences of EMIC waves during 119 storms occurring throughout the CRRES mission. The storms were defined using the Sym‐H index. The storm was divided into three phases: pre‐onset, main, and recovery (80% of minimum Sym‐H value). The majority, 56.25%, of storm time EMIC waves were found to occur during the main phase, while 35.57% were observed in the recovery phase. The recovery phase definition was then extended to 6 days after the minimum in order to compare with past ground studies. Although more EMIC waves were observed during this extended recovery phase, the maximum occurrence rate of EMIC waves remains in the main phase. A slight increase does appear in the 4–6 days after the minimum Sym‐H value. The mean occurrence location of EMIC waves was at L = 6.07, MLT = 15.12. This suggests that EMIC waves may have been generated when the ring current and plasmasphere or plasma plume particle populations overlap, often observed during the main phase due to storm dynamics. The rise in the occurrence rate in the extended recovery phase potentially is dominated by the process of plasmaspheric expansion after the end of the storm.
Forecast assessment of topside spread F at Jicamarca
Authors: Aveiro H. C. , Hysell D. L.
Published: December 2010

The Jicamarca Unattended Long Term Investigations of the Ionosphere and Atmosphere (JULIA) radar operated from August 1996 through the present time, making a total of approximately 1500 nights of ionospheric irregularities associated with equatorial spread F (ESF) observations under different seasons, solar flux levels, and geomagnetic conditions. The climatology, persistence, and correlation with the phase of the Moon of premidnight and postmidnight irregularities are evaluated, and different forecasting tools are compared. During equinox, 1 day persistence information improves the forecast over climatology alone for most solar flux and geomagnetic activity conditions, with a significant improvement during periods at low solar flux. December solstice ESF observations show a high correlation with the lunar phase, with periods close to the full Moon presenting the highest probability of ESF occurrence. Using this information for geomagnetically quiet periods during December solstice, we further improve the forecast over the climatological model. For postmidnight and premidnight June solstice ESF, however, climatology still gives the best forecasting results.
Network strain filter: A new tool for monitoring and detecting transient deformation signals in GPS arrays
Authors: Ohtani Ryu , McGuire Jeffrey J. , Segall Paul
Published: December 2010

We have developed a tool to detect transient deformation signals from large‐scale (principally GPS) geodetic arrays, referred to as a Network Strain Filter (NSF). The strategy is to extract spatially and temporally coherent signals by analyzing data from entire geodetic networks simultaneously. The NSF models GPS displacement time series as a sum of contributions from secular motion, transient displacements, site‐specific local benchmark motion, reference frame errors, and white noise. Transient displacements are represented by a spatial wavelet basis with temporally varying coefficients that are estimated with a Kalman filter. A temporal smoothing parameter is also estimated online by the filter. The problem is regularized in the spatial domain by minimizing a smoothing (Laplacian) norm of the transient strain rate field. To test the performance of the NSF, we carried out numerical tests using the Southern California Integrated GPS Network station distribution and a 3 year long synthetic transient in a 6 year time series. We demonstrate that the NSF can identify the transient signal, even when the colored noise amplitude is comparable to that of transient signal. Application of the method to actual GPS data from the Japanese GPS network (GEONET) on the Boso Peninsula also shows that the NSF can detect transient motions resulting from aseismic fault slip.
Design principles of nuclear receptor signaling: how complex networking improves signal transduction
Authors: Kolodkin Alexey N , Bruggeman Frank J , Plant Nick , Moné Martijn J , Bakker Barbara M , Campbell Moray J , van Leeuwen Johannes P T M , Carlberg Carsten , Snoep Jacky L , Westerhoff Hans V
Published: December 2010

The topology of nuclear receptor (NR) signaling is captured in a systems biological graphical notation. This enables us to identify a number of ‘design’ aspects of the topology of these networks that might appear unnecessarily complex or even functionally paradoxical. In realistic kinetic models of increasing complexity, calculations show how these features correspond to potentially important design principles, e.g.: (i) cytosolic ‘nuclear’ receptor may shuttle signal molecules to the nucleus, (ii) the active export of NRs may ensure that there is sufficient receptor protein to capture ligand at the cytoplasmic membrane, (iii) a three conveyor belts design dissipating GTP‐free energy, greatly aids response, (iv) the active export of importins may prevent sequestration of NRs by importins in the nucleus and (v) the unspecific nature of the nuclear pore may ensure signal‐flux robustness. In addition, the models developed are suitable for implementation in specific cases of NR‐mediated signaling, to predict individual receptor functions and differential sensitivity toward physiological and pharmacological ligands.
Integrative model of genomic factors for determining binding site selection by estrogen receptor‐α
Authors: Joseph Roy , Orlov Yuriy L , Huss Mikael , Sun Wenjie , Li Kong Say , Ukil Leena , Fu Pan You , Li Guoliang , Lim Michael , Thomsen Jane S , Ruan Yijun , Clarke Neil D , Prabhakar Shyam , Cheung Edwin , Liu Edison T
Published: December 2010

A major question in transcription factor (TF) biology is why a TF binds to only a small fraction of motif eligible binding sites in the genome. Using the estrogen receptor‐α as a model system, we sought to explicitly define parameters that determine TF‐binding site selection. By examining 12 genetic and epigenetic parameters, we find that an energetically favorable estrogen response element (ERE) motif sequence, co‐occupancy by the TF FOXA1, the presence of the H3K4me1 mark and an open chromatin configuration in the pre‐ligand state provide specificity for ER binding. These factors can model estrogen‐induced ER binding with high accuracy (ROC‐AUC=0.95 and 0.88 using different genomic backgrounds). Moreover, when assessed in another estrogen‐responsive cell line, this model was highly predictive for ERα binding (ROC‐AUC=0.86). Variance in binding site selection between MCF‐7 and T47D resides in sites with suboptimal ERE motifs, but modulated by the chromatin configuration. These results suggest a definable interplay between sequence motifs and local chromatin in selecting TF binding.
Single‐gene tuning of Caulobacter cell cycle period and noise, swarming motility, and surface adhesion
Authors: Lin Yihan , Crosson Sean , Scherer Norbert F
Published: December 2010

Sensor histidine kinases underlie the regulation of a range of physiological processes in bacterial cells, from chemotaxis to cell division. In the gram‐negative bacterium Caulobacter crescentus, the membrane‐bound histidine kinase, DivJ, is a polar‐localized regulator of cell cycle progression and development. We show that DivJ localizes to the cell pole through a dynamic diffusion and capture mechanism rather than by active localization. Analysis of single C. crescentus cells in microfluidic culture demonstrates that controlled expression of divJ permits facile tuning of both the mean and noise of the cell division period. Simulations of the cell cycle that use a simplified protein interaction network capture previously measured oscillatory protein profiles, and recapitulate the experimental observation that deletion of divJ increases the cell cycle period and noise. We further demonstrate that surface adhesion and swarming motility of C. crescentus in semi‐solid media can also be tuned by divJ expression. We propose a model in which pleiotropic control of polar cell development by the DivJ–DivK–PleC signaling pathway underlies divJ‐dependent tuning of cell swarming and adhesion behaviors.
Evolution, genomic analysis, and reconstruction of isobutanol tolerance in Escherichia coli
Authors: Atsumi Shota , Wu Tung‐Yun , Machado Iara M P , Huang Wei‐Chih , Chen Pao‐Yang , Pellegrini Matteo , Liao James C
Published: December 2010

Escherichia coli has been engineered to produce isobutanol, with titers reaching greater than the toxicity level. However, the specific effects of isobutanol on the cell have never been fully understood. Here, we aim to identify genotype–phenotype relationships in isobutanol response. An isobutanol‐tolerant mutant was isolated with serial transfers. Using whole‐genome sequencing followed by gene repair and knockout, we identified five mutations (acrA, gatY, tnaA, yhbJ, and marCRAB) that were primarily responsible for the increased isobutanol tolerance. We successfully reconstructed the tolerance phenotype by combining deletions of these five loci, and identified glucosamine‐6‐phosphate as an important metabolite for isobutanol tolerance, which presumably enhanced membrane synthesis. The isobutanol‐tolerant mutants also show increased tolerance to n‐butanol and 2‐methyl‐1‐butanol, but showed no improvement in ethanol tolerance and higher sensitivity to hexane and chloramphenicol than the parental strain. These results suggest that C4, C5 alcohol stress impacts the cell differently compared with the general solvent or antibiotic stresses. Interestingly, improved isobutanol tolerance did not increase the final titer of isobutanol production.
Hypothesis: Klotho can decouple insulin resistance from the associated pathophysiology
Authors: Watve Milind , Baig Ulfat
Published: December 2010

A very fundamental paradox of insulin resistance is that in a wide variety of animal models impairment of insulin signaling increases life span. But in humans it increases the risk of a range of fatal disorders. The Klotho protein appears to resolve this paradox. Overexpression of the Klotho gene increases longevity in mammals by inducing insulin resistance. But the Klotho protein is simultaneously anti-inflammatory, antioxidant and pro-angiogenesis. A number of other studies have indicated that systemic inflammation, angiogenesis dysfunction and oxidative stress are the main causes of pathological complications of diabetes. The Klotho protein has demonstrated that insulin resistance can be decoupled from these pathogenic mechanisms and if decoupled it might contribute to longevity in humans as well. However, insulin resistance has always been treated as the therapeutic target for type 2 diabetes. Our hypothesis suggests that therapy for type 2 diabetes should deviate from insulin resistance and focus on normalizing angiogenic, inflammatory and oxidative mechanisms.