bluuebunny/crossref_metadata_2025 huggingface dataset:
Analytical expressions for entrainment and detrainment in cumulus convection
Authors: de Rooy Wim C. , Pier Siebesma A.
Published: July 2010

Analytical expressions for entrainment and detrainment are derived based on general total water specific humidity and mass budget equations. From these expressions, containing a small‐scale turbulent and a larger‐scale organized term, a physical picture emerges for a shallow cumulus cloud ensemble in which the individual clouds have a massive entrainment at the bottom, lateral turbulent mixing with constant mass flux between bottom and top, and massive detrainment at the top. Combining these results with the general budget equation for vertical velocity, new formulae for entrainment and detrainment rates can be expressed in terms of buoyancy, vertical velocity and cloud fraction. For a variety of shallow convection cases, results from large‐eddy simulations show a good correspondence of these new formulae with more traditional methods to diagnose entrainment and detrainment rates. Moreover, the formulae give insight into the behaviour and the physical nature of the mixing coefficients. They explain the observed large variability of the detrainment. The formulae cannot be directly applied as a parametrization. However, it is demonstrated how they can be used to evaluate existing parametrization approaches and as a sound physical base for future parametrization developments. Copyright © 2010 Royal Meteorological Society
Zap70 Functions to Maintain Stemness of Mouse Embryonic Stem Cells by Negatively Regulating Jak1/Stat3/c-Myc Signaling
Authors: Cha Young , Moon Bo-hyun , Lee Mi-ok , Ahn Hee-jin , Lee Hye-jin , Lee Kyung-ah , Fornace Albert J. , Kim Kwang-soo , Cha Hyuk-jin , Park Kyung-soon
Published: July 2010

Zeta-chain-associated protein kinase-70 (Zap70), a Syk family tyrosine kinase, has been reported to be present exclusively in normal T-cells, natural killer cells, and B cells, serving as a pivotal regulator of antigen-mediated receptor signaling and development. In this study, we report that Zap70 is expressed in undifferentiated mouse embryonic stem cells (mESCs) and may critically regulate self-renewal and pluripotency in mESCs. We found that Zap70 knocked-down mESCs (Zap70KD) show sustained self-renewal and defective differentiation. In addition, we present evidence that the sustained self-renewal in Zap70KD is associated with enhanced Jak/Stat3 signaling and c-Myc induction. These altered signaling appears to result from upregulated leukemia inhibitory factor receptor and downregulated src homology region 2 domain containing phosphatase 1 (SHP-1) phosphatase activity. On the basis of these results, we propose that in undifferentiated mESCs, Zap70 plays important roles in modulating the balance between self-renewal capacity and pluripotent differentiation ability as a key regulator of the Jak/Stat3/c-Myc signaling pathway.
Reflection and transmission of water waves in a two‐layer fluid flowing through a channel with undulating bed
Authors: Mohapatra S. , Bora S.N.
Published: July 2010

Within the framework of two‐dimensional linear water wave theory, we consider the problem of normal surface wave propagation over small undulations in a channel flow consisting of a two‐layer fluid with the upper layer bounded by a fixed wall, considered as an approximation to the free surface, and the lower one by a bottom surface which has small undulations. The effects of surface tension at the surface of separation is neglected. Assuming irrotational motion, a perturbation analysis is employed to calculate the first order corrections to the velocity potentials in the two‐layer fluid by using Fourier transform appropriately and also to calculate the reflection and transmission coefficients in terms of integrals involving the shape function c (x) representing the bottom undulation. Two special forms of the shape function are considered for which explicit expressions for reflection and transmission coefficients are evaluated. For the specific case of a patch of sinusoidal ripples having the same wave number throughout, the reflection coefficient up to the first order is an oscillatory function in the quotient of twice the interface wave number and the ripple wave number. When this quotient is one, the theory predicts a resonant interaction between the bed and the interface, and the reflection coefficient becomes a multiple of the number of ripples. But the theory breaks down at resonance and it is applicable only to infinitesimal reflection when the reflection coefficient cannot assume large value, and away from resonance. Hence, the results demonstrated here is valid for up to the near resonant cases only. Again, when a patch of sinusoidal ripples having two different wave numbers is considered, the resonant interaction between the bed and the interface attains in the neighborhood of two (singular) points along x‐axis (when the ripple wave numbers of the bottom undulation become twice as large as interface wave number). The theoretical observations are presented in graphical form.
Water‐waves modes trapped in a canal by a near‐surface rough body
Authors: Cardone G. , Durante T. , Nazarov S.A.
Published: July 2010

The problem about a body in a three dimensional infinite channel is considered in the framework of the theory of linear water‐waves. The body has a rough surface characterized by a small parameter ε > 0 while the distance of the body to the water surface is also of order ε. Under a certain symmetry assumption, the accumulation effect for trapped mode frequencies is established, namely it is proved that, for any given d > 0 and integer N > 0, there exists a number ε (d, N) > 0 such that the problem has at least N eigenvalues in the interval (0, d) of the continuous spectrum in the case ε ∈ ( 0, ε (d, N)). The corresponding eigenfunctions decay exponentially at infinity, have finite energy, and imply trapped modes.
Autologous bone marrow cell infusion therapy for liver cirrhosis patients
Authors: Terai Shuji , Sakaida Isao
Published: July 2010

We developed a novel cell therapy, autologous bone marrow cell infusion (ABMi) therapy, using autologous bone marrow, for liver cirrhosis patients. Our study depends on the findings from basic studies that bone marrow cell infusion repairs liver fibrosis in the cirrhotic liver, and improves liver function and the survival rate. Beginning in November 2003, we started a clinical study and found that ABMi therapy was safe and effective for liver cirrhosis patients. Multicenter trials in Japan and Korea have also shown the effectiveness of ABMi therapy. In this review, we report the current status of ABMi therapy for liver cirrhosis patients.
Solvent Extraction: Kinetic Study of Major and Minor Compounds
Authors: Baümler Erica R. , Crapiste Guillermo H. , Carelli Amalia A.
Published: July 2010

The effects of temperature and contact time on lipid extraction from sunflower collets was investigated in a batch extractor with hexane as solvent. The total removed material varied in quantity and composition due to changes in temperature and contact time. Higher temperatures enhanced oil extraction as well as increased the tocopherol and phospholipid contents of the oil. The kinetic data for triglycerols, phospholipid and tocopherols extraction were interpreted by using an equation that considers extraction as the sum of two components: diffusion and washing. Effective diffusion coefficients for oil, tocopherols and phospholipid at different temperatures were determined. Control of temperature and contact time are essential to obtain good quality oil and reduce refining costs. Extraction at 60 °C and short contact times (30 min) obtained high oil yield (98%) accompanied by significant tocopherol extraction (>99%) and reduced phospholipid extraction (66%).
Raumplanerische Koordination aus rechtlicher Sicht
Authors: Durner Wolfgang
Published: July 2010

The Federal Administrative Court’s judgement of 03/16/2006 concerning the airport Berlin-Schönefeld seems to announce a renaissance of the idea of coordination by spatial planning. Even after this decision, however, the Länder’s comprehensive regional planning will not be able to effectively coordinate the federal state’s and the European Union’s sectoral plannings. The paper elaborates various possible strategies to improve the legal framework for comprehensive spatial planning in Germany.
Calcium regulation of the ATPase activity of Physarum and scallop myosins using hybrid smooth muscle myosin: The role of the essential light chain
Authors: Zhang Ying , Nakamura Akio , Kawamichi Hozumi , Yoshiyama Shinji , Katayama Takeshi , Kohama Kazuhiro
Published: July 2010

To examine the role of two light chains (LCs) of the myosin II on Ca2+ regulation, we produced hybrid heavy meromyosin (HMM) having LCs from Physarum and/or scallop myosin using the smooth muscle myosin heavy chain. Ca2+ inhibited motility and ATPase activity of hybrid HMMs with LCs from Physarum myosin but activated those of hybrid HMM with LCs from scallop myosin, indicating an active role of LCs. ATPase activity of hybrid HMMs with LCs from different species showed the same effect by Ca2+ even though they did not support motility. Our results suggest that communication between the original combinations of LC is important for the motor function.
Endothelin‐1 Enhances Superoxide and Prostaglandin E2 Production of Isolated Diabetic Glomeruli
Authors: Lee Jia‐Jung , Hung Chi‐Chih , Tsai Jer‐Chia , Chen Hung‐Chun
Published: July 2010

Endothelin‐1 (ET‐1) plays an important role in the pathogenic mechanism of diabetic nephropathy. However, the regulatory effects of ET‐1 on superoxide and prostaglandin E2 (PGE2) in diabetic glomeruli are unclear. The aim of this study was to determine whether ET‐1 exerts a differential effect on the production of superoxide and PGE2 in diabetic glomeruli. The regulatory effects of indomethacin, insulin, dexamethasone, and heparin were also investigated. Freshly isolated glomeruli were obtained from normal and streptozotocin‐induced diabetic rats for 1 week (DM1W), 1 month (DM1M), and 3 months (DM3M), respectively. Our results showed that the basal superoxide production of isolated glomeruli was significantly higher in DM1M and DM3M than in the normal rats (p < 0.01). ET‐1 stimulated superoxide production in normal, DM1W and DM1M glomeruli (p < 0.01) but not in DM3M rats. The basal production of PGE2 in isolated glomeruli did not differ between diabetic and normal rats. ET‐1 also stimulated PGE2 production in diabetic rats (p < 0.05). Pretreatment with indomethacin further enhanced ET‐1‐stimulated superoxide production in all groups of diabetic rats (p < 0.05), while the ET‐1‐stimulated PGE2 production was attenuated by indomethacin. Insulin, dexamethasone and heparin had no additional effects on ET‐1‐mediated superoxide and PGE2 production. In conclusion, basal glomerular production of superoxide but not PGE2 was increased in the diabetic glomeruli. ET‐1 further stimulated production of both superoxide and PGE2. Indomethacin could enhance ET‐1‐stimulated superoxide production while attenuating PGE2 production.
Recurrent Factitious Subcutaneous Emphysema: Report of a Complex Case in a Young Woman and a Literature Review
Authors: Lee Yi‐Pei , Lee Julia Yu‐Yun
Published: July 2010

Subcutaneous emphysema (SE) can be caused by antecedent trauma, surgery, rupture of visceral organs or serious infection from gas‐forming microorganisms. Factitious SE is very rare; only about a dozen cases have been reported. Most patients had an underlying psychiatric condition or relevant history. The diagnosis and management of factitious SE are challenging. We report a new case of factitious SE with a very complex clinical course. A 29‐year‐old woman was seen at consultation for recurrent attacks of painful soft tissue swelling, affecting her chest wall, abdomen and neck over several months. Factitious disease was suspected because of the negative medical history of identifiable visceral perforations or gas‐forming infections and the presence of multiple bizarre linear scars on the arm. This was supported by finding multiple recent puncture marks on the neck, chest and upper extremities on close inspection. The patient's history was remarkable for multiple stressful events in her life, frequent job changes, substance abuse and suicide attempts. Psychiatric evaluation revealed adjustment disorder with depression and anxiety, cluster B personality with bipolar II disorder and substance abuse. During the 1‐year period, she had 20 visits to our ER for attacks of SE affecting various parts of her body. This case illustrates that self‐infliction should be suspected in a patient presenting with medically unexplained recurrent SE and a hollow history, and one should search for puncture marks to support the diagnosis.
Host species critical for offspring fitness and sex ratio for an oligophagous parasitoid: implications for host coexistence
Authors: Stenberg J.A. , Hambäck P.A.
Published: July 2010

In theory, inferior apparent competitors sharing a natural enemy with superior apparent competitors should be excluded in the absence of stabilising factors. Nevertheless, plentiful examples of coexisting apparent competitors exist. In this paper, we show that parasitoid resource competition within hosts affects both parasitoid sex ratio and female body size, with implication for population growth and apparent competition between the two closely related hosts experiencing a strong asymmetry in their interaction. While the superior competitor delivers parasitoids with higher fitness to the shared parasitoid pool, the inferior competitor delivers a higher proportion of female parasitoids. Hence, the inferior host experience an inflow of fit parasitoids from the superior competitor, which should increase the risk of exclusion, but also an outflow of parasitoid females, which should reduce the risk of exclusion and increase stability. We conclude that differential outcomes of parasitoid resource competition in different host species may have profound effects on shared parasitoid populations and should be included in future studies of apparent competition between hosts.
Assessment of direct numerical simulation data of turbulent boundary layers
Authors: SCHLATTER PHILIPP , ÖRLÜ RAMIS
Published: July 2010

Statistics obtained from seven different direct numerical simulations (DNSs) pertaining to a canonical turbulent boundary layer (TBL) under zero pressure gradient are compiled and compared. The considered data sets include a recent DNS of a TBL with the extended range of Reynolds numbersReθ= 500–4300. Although all the simulations relate to the same physical flow case, the approaches differ in the applied numerical method, grid resolution and distribution, inflow generation method, boundary conditions and box dimensions. The resulting comparison shows surprisingly large differences not only in both basic integral quantities such as the friction coefficientcfor the shape factorH12, but also in their predictions of mean and fluctuation profiles far into the sublayer. It is thus shown that the numerical simulation of TBLs is, mainly due to the spatial development of the flow, very sensitive to, e.g. proper inflow condition, sufficient settling length and appropriate box dimensions. Thus, a DNS has to be considered as a numerical experiment and should be the subject of the same scrutiny as experimental data. However, if a DNS is set up with the necessary care, it can provide a faithful tool to predict even such notoriously difficult flow cases with great accuracy.
Population characteristics and biology of two populations of Archaster angulatus (Echinodermata: Asteroidea) in different habitats off the central-western Australian coast
Authors: Lawrence J.M. , Keesing J.K. , Irvine T.R.
Published: July 2010

We examined habitat, population size-structure, colour dimorphism, reproductive behaviour, arm loss and the relation between arm regeneration to pyloric caeca indices in populations at Whitford Rock (WR) and Port Beach (PB) in January 2009. The sediment was fine sand at WR and a mix of larger particles at PB. Individuals at PB were predominantly orange and more uniform in colour than those at WR, which were predominantly grey. Body size and pyloric caeca index of individuals at WR were greater than those of individuals at PB, indicating the nutritional condition was better at WR. This suggests the quantity or quality of food at WR was better. Organic matter of the pyloric caeca and body wall of intact and regenerating individuals at both sites were similar, indicating loss of an arm did not affect gross proximate composition of the organs. Sea stars with regenerating arms made up 5.4 and 8.4 % of the populations observed. Despite the very small size of the gonads, some individuals were in the pseudocopulatory position, indicating this behaviour occurs even when gametes are not present. In every case observed, the male of the pseudocopulating pair was situated above the female. Given the abundance of this species in nearshore habitats dominated by sediment, it is likely to be ecologically important. However much of the biology and ecology of the species, even its diet, remain unknown. This together with its unusual mode of reproductive behaviour involving pseudocopulation, which is only known from two other species of asteroids, underscore the need for more research on Archaster angulatus.
Morphological structures of the shell of Mytilus trossulus and Crenomytilus grayanus in early ontogenesis and their importance in the taxonomy of Mytilinae (Bivalvia: Mytilidae)
Authors: Evseev G.A. , Kolotukhina N.K. , Kulikova V.A.
Published: July 2010

The morphostructures of larval and juvenile shells of two common species of bivalves of the north-western Sea of Japan, Mytilus trossulus and Crenomytilus grayanus have been examinated. Two types of morphological features were identified on the basis of the results obtained and comparison with materials of other species of the subfamily Mytilinae. One group of morphological features (absence or presence of the nepioconch; form and size of posterior lateral teeth) characterizes the higher taxonomic categories, while the other one (morphological details of general outline of the secondary prodissoconch and juvenile shell; ratio shell height/length; form, size and number of provincular and additional teeth; number of posterior lateral teeth, and others) serves to separate taxa of the generic or specific ranks.
Feeding ecology of the Brazilian silversideAtherinella brasiliensis(Atherinopsidae) in a sub-tropical estuarine ecosystem
Authors: Contente R.F. , Stefanoni M.F. , Spach H.L.
Published: July 2010

The feeding ecology of the Brazilian silverside,Atherinella brasiliensis, in a sub-tropical estuary of Brazil was investigated through the gut analysis of 1431 individuals. We described dietary composition and analysed seasonal, estuarine habitat, and body size variations in the diet; trophic level; feeding diversity; and gut fullness indices. Results reveal thatA. brasiliensisis a typical, generalistic and opportunistic predator that makes use of a wide array of prey types (at least 89 different types), with zooplankton (mainly calanoids), diatoms, terrestrial insects, and plant detritus making up the bulk of the overall diet. The exotic calanoidTemora turbinataranked as the primary prey. A wide feeding diversity (meanH′ = 2.26), low trophic level (meanTROPH = 2.57), and high gut replenishment were persistent across seasons and habitats. Diet composition varied largely and significantly with respect to habitat, season, and body size. A closer assessment showed that habitat and season had a stronger effect on diet than fish size.
Spatial aggregation patterns of free-living marine nematodes in contrasting sandy beach micro-habitats
Authors: Gingold Ruth , Ibarra-Obando Silvia E. , Rocha-Olivares Axayácatl
Published: July 2010

In the absence of chemical or physical gradients, random displacement of organisms can result in unpredictable distribution patterns. In spite of a limited locomotive capability, marine nematodes may choose where to settle after re-suspension and may maintain their position in the sediment under calm conditions, leading to small-scale (<1 m) spatial variability. However, in more energetic environments, nematodes become re-suspended with sediments and re-distributed at distances dependent on prevalent hydrodynamic regimes, from metre- to decametre-scale or more. In this study, we tested the hypothesis that micro-habitats (i.e. runnels and sandbars) in a macrotidal sandy beach influence the distribution patterns of free-living marine nematodes by exhibiting contrasting hydrodynamic regimes. Specifically, we predicted patchier distributions in the calmer environment (runnel). We sampled nematodes in each habitat from <1 m to decametre scales. Our results show more heterogeneous spatial distributions in the runnel, presumably owing to a predominance of active displacement under calmer conditions and sediment cohesion by algal films. Biological similarity among runnel replicates was low, whereas replicates from the sandbar exhibited higher similarity, presumably because of homogenization of the sediment and inhabiting fauna by tidal currents. A significant negative correlation between biological similarity and sampling distance was found in the runnel, but not in the sandbar. The most similar samples were the closest in the runnel and the most distant in the sandbar. More patchily distributed taxa were found in the runnel and a larger fraction of homogeneously or randomly distributed taxa in the sandbar. We conclude that different hydrodynamic regimes in contrasting intertidal micro-habitats significantly influenced the nematofaunal distribution, resulting in different spatial patterns next to one another in the same beach. This has significant implications for sampling and monitoring designs and begs the need for detailed studies about the physical and biological processes governing meiobenthic communities.
THE ETHICAL AND POLITICAL CONDITIONS OF MUSICAL ACTIVITY IN POLAND AFTER WORLD WAR II
Authors: Humięcka-Jakubowska Justyna
Published: July 2010

Musical activity is one of the many forms of purposeful human activity. Its peculiarity lies in its creative character – an attribution which brings to mind the concept elaborated by Mooney (1963), in which the quality of creativeness was evoked in relation to the product (or artistic work), the process of its production and its author. One aspect of Mooney's reflections that are of importance to the present discussion is his observation that a considerable influence on creative activity is exercised by the favourable or detrimental conditions under which it arises (atmosphere, social environment, historical context).
WITOLD LUTOSŁAWSKI AND THE CRAFT OF WRITING NOTHING
Authors: Rice Hugh Collins
Published: July 2010

From the moment Schoenberg saw the need to use the designations Hauptstimme and Nebenstimme, the issue of differentiating material in complex post-tonal scores has been significant. It has formal and textural connotations, and it relates directly to the experience of listening to this music.
Neuroendocrine features of attachment in infants and nonhuman primates
Authors: Seltzer Leslie J. , Pollak Seth D.
Published: July 2010

The translation of research findings from other primates to humans, and from infants to adults within our own species, requires great care. If the many neurological, behavioral and adaptive distinctions between these groups are not precisely defined and considered, erroneous conclusions about evolutionary history and developmental processes may result.
French Stock exchanges and regulation during World War II
Authors: Oosterlinck Kim
Published: July 2010

Based on archives of the French brokers, the French finance ministry and the occupying forces, this article analyses the motivations of the legal changes imposed on the French exchanges during the war. Most of the measures taken by the Vichy government were meant to stimulate the demand for French state bonds. Three main tools were used to render stocks as unattractive as possible: forced registration, imposition of a maximum threshold for stock prices and taxation. The article suggests that forced registration and the cap on maximum prices were the most efficient tools.
The impact of individual quotas on technical efficiency: does quality matter?
Authors: DRESDNER JORGE , CAMPOS NÉLYDA , CHÁVEZ CARLOS
Published: July 2010

We estimate the technical efficiency gains of introducing individual quotas (IQs) in fisheries. Our estimates are based on two samples of vessels, considering a potential self-selection bias and controlling for quality changes in landings induced by the IQ system. The results suggest that the introduction of IQs has an important positive impact on fleet efficiency, and that properly measuring this impact requires controlling for the self-selection bias and quality changes induced by the regulatory shift.
Climate change and its impacts: growing stress factors for human societies
Authors: Beniston Martin
Published: July 2010

The realization that human beings need to be concerned about the only ‘life-support system’ that the Earth and its environment provides stems perhaps in part from the fact that, until fairly recently, the evolution of humankind was largely dependent on the quality of the environment and the resources it provides in terms of water, food, and favourable health conditions. These are as vital as ever, despite current levels of technology and apparent resilience in the face of often degraded environments in many parts of the world. Today, the conditions for human sustainability (i.e. water quality and quantity, food security, and health) are potentially under threat as a result of numerous human-induced factors; among these, climate change is certainly one of the more durable aspects of anthropogenic disruptions to natural resources. This article will therefore focus on the possible evolution of climate in the course of the twenty-first century and on a number of key climate impacts that may determine the future course of human societies, as well as issues that may confront them such as rivalries over natural resources and possible environmentally driven conflicts and migrations.
Seasonal influence on polar cap patches in the high‐latitude nightside ionosphere
Authors: Wood A. G. , Pryse S. E.
Published: July 2010

The influence of the season on the patch‐to‐background density ratio of polar cap patches in the nightside ionosphere was observed above northern Scandinavia around solar maximum (1999–2001). This is the first study of the seasonal effect in the nightside polar ionosphere. The observations were conducted by the European Incoherent Scatter Svalbard Radar under conditions favorable for patches based on the high‐latitude plasma convection pattern, the interplanetary magnetic field, and an absence of in situ precipitation. Patch‐to‐background ratios of up to 9.4 ± 2.9 were observed between midwinter and equinox, with values of up to 1.9 ± 0.2 in summer. As the patch‐to‐background ratios in summer were <2, the enhancements could not formally be called patches; however, these were significant density enhancements within the antisunward cross‐polar flow. Aberystwyth University's PLASLIFE (PLASma LIFEtime) computer simulation was used to model the observed seasonal trend in the patch‐to‐background ratio and to establish reasons for the difference between winter and summer values. This difference was primarily attributed to variation in the chemical composition of the atmosphere, which, in summer, both reduced the electron densities of the plasma drawn into the polar cap on the dayside and enhanced plasma loss by recombination. A secondary factor was the maintenance of the background polar ionosphere by photoionization in summer.
Mesospheric temperature and atomic oxygen response during the January 2009 major stratospheric warming
Authors: Shepherd Marianna G. , Cho Young‐Min , Shepherd Gordon G. , Ward William , Drummond James R.
Published: July 2010

The study examines the response of the mesosphere/lower thermosphere to the major stratospheric warming (SSW) event from January 2009, as seen in the OH and O2(0,1) atmospheric band airglow observations nominally at 87 and 94 km, respectively, by a SATI (Spectral Airglow Temperature Imager) instrument installed at the Polar Environment Atmospheric Research Laboratory (PEARL) at Eureka (80°N, 86°W) as part of the Canadian Network for the Detection of Atmospheric Change. At the time of the SSW, the airglow emissions and the derived rotational temperatures appear depleted and decreased, followed by an enhancement of the airglow emission rates during the SSW recovery phase, while the temperatures returned to their pre‐event state. An empirical relationship between OH airglow peak altitude determined by SABER (Sounding of the Atmosphere by Broadband Emission Radiometry) and SATI integrated emission rates allowed perturbed OH and O2(0,1) airglow altitudes to be assigned to the SATI observations. From these, the O volume mixing ratio (VMR), corresponding to the observed OH and O2(0,1) airglow emission rates were modeled. Atomic oxygen depletion by a factor of ∼5 was observed during the SSW and lasted for about 5 days. During the SSW recovery phase, the O VMR giving rise to the observed O2(0,1) airglow emission rates increased by a factor of 3.5 from its pre‐SSW level and 17 times from the peak of the SSW. Perturbations in the OH and O2(0,1) airglow layers with periods of 4, 6, 8, and 12 h indicate nonlinear interaction between zonally symmetric semidiurnal tides and planetary waves.
Rayleigh lidar observations of reduced gravity wave activity during the formation of an elevated stratopause in 2004 at Chatanika, Alaska (65°N, 147°W)
Authors: Thurairajah Brentha , Collins Richard L. , Harvey V. Lynn , Lieberman Ruth S. , Mizutani Kohei
Published: July 2010

We report Rayleigh lidar measurements of nightly temperature profiles in the 40–80 km altitude region and 15 min relative density profiles in the 40–50 km altitude region at Poker Flat Research Range, Chatanika, Alaska (65°N, 147°W), in December, January, and February over three winters (2002–2003, 2003–2004, and 2004–2005). We characterize the gravity wave activity in terms of the measurements of buoyancy period and relative density fluctuations and estimate the potential energy density and growth of potential energy density with altitude. We use satellite and reanalysis data to analyze the synoptic structure of the stratospheric vortex and the Aleutian anticyclone, the planetary wave activity, and the mean winds. These three winters have a major stratospheric warming in 2002–2003, an extreme warming event in 2003–2004 resulting in an elevated stratopause, and no warming in 2004–2005. The gravity wave activity shows significant interannual variability, with an average potential energy density of 2.1 J/kg in 2002–2003, 1.1 J/kg in 2003–2004, and 5.7 J/kg in 2004–2005. We find a positive correlation of 0.74 between the gravity wave activity in the upper stratosphere and the winds in the lower stratosphere where the winds are lightest. The reduction in gravity wave activity in 2002–2003 relative to 2004–2005 reflects the influence of the Aleutian anticyclone that is present over Chatanika in 2002–2003 but absent in 2004–2005. The occurrence of lower gravity wave activity in 2003–2004, when the Aleutian anticyclone is present less often than in 2002–2003, supports recent modeling studies that indicate that the elevated stratopause is formed due to a reduction of gravity waves propagating upward into the mesosphere.
Dust aerosol optical properties retrieval and radiative forcing over northwestern China during the 2008 China‐U.S. joint field experiment
Authors: Ge J. M. , Su J. , Ackerman T. P. , Fu Q. , Huang J. P. , Shi J. S.
Published: July 2010

The Atmosphere Radiation Measurements Program's Ancillary Facility (AAF/SMART‐COMMIT) was deployed to Zhangye (39.082°N, 100.276°E), which is located in a semidesert area of northwest China, during the period of late April to mid June in 2008. We selected 11 cases to retrieve dust aerosol optical depth (AOD), Angstrom exponent, size distribution, single‐scattering albedo (SSA) and asymmetry parameter (ASY) from multifilter rotating shadowband radiometer (MFRSR) measurements. These cases are dominated by large particles with Angstrom exponent values ranging from 0.34 to 0.93. The values of AOD at 0.67 μm range from 0.07 to 0.25. The mean SSA value increases with wavelength from 0.76 ± 0.02 at 0.415 μm to 0.86 ± 0.01 at 0.870 μm, while the mean ASY value decreases from 0.74 ± 0.04 to 0.70 ± 0.02. Before estimating dust aerosol direct radiative forcing, a radiative closure experiment was performed to verify that the retrieved aerosol optical properties and other input parameters to the radiative transfer model appropriately represent atmospheric conditions. The daytime‐averaged differences between model simulations and ground observations are −8.5, −2.9, and −2.1 W m−2 for the total, diffuse, and direct normal fluxes, respectively. The mean difference in the instantaneous reflected solar fluxes at the top of atmosphere (TOA) between the model and CERES observations is 8.0 W m−2. The solar aerosol direct radiative forcing (ARF), averaged over a 24 h period, at the surface is −22.4 ± 8.9 W m−2, while the TOA ARF is small and has an average value of only 0.52 ± 1.69 W m−2. The daily averaged surface aerosol radiative forcing efficiency at 0.5 μm is −95.1 ± 10.3 W m−2τ−1. Our results illustrate that the primary role of dust aerosol is to alter the distribution of solar radiation within the climate system rather than to reflect solar energy to space. We assess the satellite aerosol optical depth products from Mutiangle Imaging Spectroradiometer (MISR) and Moderate Resolution Imaging Spectroradiometer (MODIS) observations by comparing them with our ground‐based retrievals. Reasonable agreements with the ground‐based observations are found for the MISR product and MODIS Deep Blue product.
Zonal drift of plasma particles inside equatorial plasma bubbles and its relation to the zonal drift of the bubble structure
Authors: Huang Chao‐Song , de La Beaujardiere O. , Pfaff R. F. , Retterer J. M. , Roddy P. A. , Hunton D. E. , Su Y.‐J. , Su S.‐Y. , Rich F. J.
Published: July 2010

It has been observed that the zonal drift velocity of equatorial plasma bubbles is generally eastward. However, it has not been well understood whether the zonal drift of plasma bubbles is the same as the ambient plasma drift and what process causes differences in the drift velocities of the ambient plasma and bubbles. In this study we analyze the ion drift velocities measured by the Defense Meteorological Satellites Program and ROCSAT‐1 satellites and the electric fields measured by the Communications/Navigation Outage Forecasting System (C/NOFS) satellite in the presence of equatorial spread F. We find that the zonal drift velocity of the plasma particles inside plasma bubbles is significantly different from the ambient plasma drift. The relative zonal velocity of the ions inside the depletion region with respect to the ambient plasma is generally westward. In most cases it can be as high as several hundreds of meters per second. The plasma bubbles detected by the C/NOFS satellite in the midnight‐dawn sector are still growing, and the polarization electric field inside the postmidnight bubbles is much stronger than the electric field in the ambient plasma. We suggest that the zonal drift velocity of the plasma particles inside the depletion region is driven by polarization electric field. When a plasma bubble is tilted, the E × B drift velocity caused by the polarization electric field has an upward component and a zonal component. Because of the zonal motion of the plasma particles inside the bubble, the eastward drift velocity of the bubble structure is faster than the ambient plasma drift for a west‐tilted bubble and slower than the ambient plasma drift for an east‐tilted bubble.
Hyperglycemia in Aneurysmal Subarachnoid Hemorrhage: A Potentially Modifiable Risk Factor for Poor Outcome
Authors: Kruyt Nyika D , Biessels Geert Jan , DeVries J Hans , Luitse Merel JA , Vermeulen Marinus , Rinkel Gabriel JE , Vandertop W Peter , Roos Yvo B
Published: July 2010

Hyperglycemia after aneurysmal subarachnoid hemorrhage (aSAH) occurs frequently and is associated with delayed cerebral ischemia (DCI) and poor clinical outcome. In this review, we highlight the mechanisms that cause hyperglycemia after aSAH, and we discuss how hyperglycemia may contribute to poor clinical outcome in these patients. As hyperglycemia is potentially modifiable with intensive insulin therapy (IIT), we systematically reviewed the literature on IIT in aSAH patients. In these patients, IIT seems to be difficult to achieve in terms of lowering blood glucose levels substantially without an increased risk of (serious) hypoglycemia. Therefore, before initiating a large-scale randomized trial to investigate the clinical benefit of IIT, phase II studies, possibly with the help of cerebral blood glucose monitoring by microdialysis, will first have to improve this therapy in terms of both safety and adequacy.
Optimized Data Preprocessing for Multivariate Analysis Applied to 99mTc-ECD SPECT Data Sets of Alzheimer's Patients and Asymptomatic Controls
Authors: Merhof Dorit , Markiewicz Pawel J , Platsch Günther , Declerck Jerome , Weih Markus , Kornhuber Johannes , Kuwert Torsten , Matthews Julian C , Herholz Karl
Published: July 2010

Multivariate image analysis has shown potential for classification between Alzheimer's disease (AD) patients and healthy controls with a high-diagnostic performance. As image analysis of positron emission tomography (PET) and single photon emission computed tomography (SPECT) data critically depends on appropriate data preprocessing, the focus of this work is to investigate the impact of data preprocessing on the outcome of the analysis, and to identify an optimal data preprocessing method. In this work, technetium-99methylcysteinatedimer (99mTc-ECD) SPECT data sets of 28 AD patients and 28 asymptomatic controls were used for the analysis. For a series of different data preprocessing methods, which includes methods for spatial normalization, smoothing, and intensity normalization, multivariate image analysis based on principal component analysis (PCA) and Fisher discriminant analysis (FDA) was applied. Bootstrap resampling was used to investigate the robustness of the analysis and the classification accuracy, depending on the data preprocessing method. Depending on the combination of preprocessing methods, significant differences regarding the classification accuracy were observed. For 99mTc-ECD SPECT data, the optimal data preprocessing method in terms of robustness and classification accuracy is based on affine registration, smoothing with a Gaussian of 12 mm full width half maximum, and intensity normalization based on the 25% brightest voxels within the whole-brain region.
Rapid Loss of Blood–Brain Barrier P-Glycoprotein Activity through Transporter Internalization Demonstrated Using a Novel in Situ Proteolysis Protection Assay
Authors: Hawkins Brian T , Rigor Robert R , Miller David S
Published: July 2010

Blood–brain barrier (BBB) P-glycoprotein activity is rapidly reduced by vascular endothelial growth factor (VEGF) acting via Src and by tumor necrosis factor-α acting via protein kinase C (PKC)β1. To probe underlying mechanism(s), we developed an in vivo, immunoblot-based proteinase K (PK) protection assay to assess the changes in the P-glycoprotein content of the BBB's luminal membrane. Infusion of PK into the brain vasculature selectively cleaved luminal membrane P-glycoprotein, leaving intracellular proteins intact. Intracerebroventricular injection of VEGF partially protected P-glycoprotein from proteolytic cleavage, consistent with transporter internalization. Activation of PKCβ1 did not protect P-glycoprotein. Thus, VEGF and PKCβ1 reduce P-glycoprotein activity by distinct mechanisms.
Differential Requirements of Sodium for Coupling of Cannabinoid Receptors to Adenylyl Cyclase in Rat Brain Membranes
Authors: Pacheco Mary A. , Ward Susan J. , Childers Steven R.
Published: July 2010

Abstract:Sodium is generally required for optimal inhibition of adenylyl cyclase by Gl/o‐coupled receptors. Canna‐binoids bind to specific receptors that act like other members of the Gl/o‐coupled receptor superfamily to inhibit adenylyl cyclase. However, assay of cannabinoid inhibition of adenylyl cyclase in rat cerebellar membranes revealed that concentrations of NaCI ranging from 0 to 150 mMhad no effect on agonist inhibition. This lack of effect of sodium was not unique to cannabinoid receptors, because the same results were observed using baclofen as an agonist for GABABreceptors in cerebellar membranes. The lack of sodium dependence was region‐specific, because assay of cannabinoid and opioid inhibition of adenylyl cyclase in striatum revealed an expected sodium dependence, with 50 mMNaCI providing maximal inhibition levels by both sets of agonists. This difference in sodium requirements between these two regions was maintained at the G protein level, because agonist‐stimulated lowKmGTPase activity was maximal at 50mMNaCI in striatal membranes, but was maximal in the absence of NaCI in cerebellar membranes. Assay of [3H]WIN 55212–2 binding in cerebellar membranes revealed that the binding of this labeled agonist was sensitive to sodium and guanine nucleotides like other Gl/o‐coupled receptors, because both NaCI and the nonhydrolyzable GTP analogue Gpp(NH)p significantly inhibited binding. These results suggest that differences in receptor‐G protein coupling exist for cannabinoid receptors between these two brain regions.
Protein Kinase C Activation AttenuatesN‐Methyl‐d‐Aspartate‐Induced Increases in Intracellular Calcium in Cerebellar Granule Cells
Authors: Snell Lawrence D. , Lorio Karen R. , Tabakoff Boris , Hoffman Paula L.
Published: July 2010

Abstract:Activation of theN‐methyl‐d‐aspartate (NMDA) subtype of glutamate receptor increases levels of intracellular calcium and can lead to stimulation of protein kinase C activity. Several reports have demonstrated that stimulation of protein kinase C can, in turn, increase electrophysiological responses to NMDA in certain cells or in oocytes expressing certain NMDA receptor subunits. In the present study, the effects of protein kinase C activation on NMDA receptor‐mediated increases in intracellular Ca2+levels were investigated in primary cultures of rat cerebellar granule cells using fura‐2 fluorescence spectroscopy. Pretreatment of the cells with the protein kinase C activator phorbol 12‐myristate 13‐acetate (PMA), but not the inactive analogue 4α‐phorbol 12‐myristate 13‐acetate,inhibitedNMDA‐induced increases in intracellular Ca2+levels. Coincubation of cells with PMA and the kinase inhibitor staurosporine or calphostin C blocked the PMA effect. The potency of NMDA was reduced twofold, and the potency of the NMDA receptor coagonist, glycine, to enhance the response to NMDA was decreased fourfold by pretreatment of cells with PMA. The effect on glycine was mimicked by pretreatment with okadaic acid, a protein phosphatase inhibitor. PMA treatment did not significantly alter Mg2+inhibition of the NMDA response but decreased the potency of the competitive antagonist CGS‐19755. These data suggest that, in cerebellar granule cells, the function of the NMDA receptor may be subject to feedbackinhibitionby protein kinase C stimulation. Under physiological conditions, this inhibition may result from a decreased effectiveness of the endogenous coagonists, glutamate and glycine.
An Endogenous Aminoenkephalinase Inhibitor: Purification and Characterization of Arg0‐Met5‐Enkephalin from Bovine Striatum
Authors: Hui Koon‐Sea , Lo Ee‐Sing , Hui Maria Po‐Ping
Published: July 2010

Abstract: Arg0‐Met5‐enkephalin (Arg0‐MEK) was isolated from bovine striatum and purified to homogeneity. The peptide was extracted with trichloroacetic acid, followed by column chromatography successively on Bio‐Sil C8, semipreparative HPLC Radial‐Pak C18, fast protein liquid chromatography (FPLC) Mono S, HPLC Ultrasphere‐ODS, Supelco C18, Lichromsorb C18, and μBondapak C18. The peptide content was followed by radioimmunoassay with an antibody against synthetic Met‐enkephalin. For each of the six HPLC and FPLC systems, the elution time of the immunoreactive fractions coincided exactly with that of synthetic Arg0‐MEK. The purified peptide showed a highly homogeneous profile in three different analytical HPLC systems. Its retention time and three‐dimensional UV spectrum were identical to those of the synthetic Arg0‐MEK. The structure of the purified material was identified by microsequencing as the hexapeptide Arg‐Tyr‐Gly‐Gly‐Phe‐Met. Ninety percent of the purified peptide was in oxidized form containing equimolar amounts of Met‐(R)‐ and Met‐(S)‐sulfoxide. The reduced Arg0‐MEK inhibited aminoenkephalinase with a Ki of 2.2 µM, and its sulfoxide analogue inhibited it with a Ki of 8.9 µM. The reduced or oxidized peptide suppressed the electrically induced contraction of rat vas deferens with an ED50 of 5 µM, and the effect could be reversed by equimolar naloxone. Our data indicate that Arg0‐MEK is an immediate Met‐enkephalin precursor and an endogenous inhibitor.
Increased Neuronal β‐Amyloid Precursor Protein Expression in Human Temporal Lobe Epilepsy: Association with Interleukin‐1α Immunoreactivity
Authors: Sheng Jin G. , Boop Frederick A. , Mrak Robert E. , Griffin W. Sue T.
Published: July 2010

Abstract: Levels of immunoreactive β‐amyloid precursor protein and interleukin‐1α were found to be elevated in surgically resected human temporal lobe tissue from patients with intractable epilepsy compared with postmortem tissue from neurologically unaffected patients (controls). In tissue from epileptics, the levels of the 135‐kDa β‐amyloid precursor protein isoform were elevated to fourfold (p < 0.05) those of controls and those of the 130‐kDa isoform to threefold (p < 0.05), whereas those of the 120‐kDa isoform (p > 0.05) were not different from control values. β‐Amyloid precursor protein‐immunoreactive neurons were 16 times more numerous, and their cytoplasm and proximal processes were more intensely immunoreactive in tissue sections from epileptics than controls (133 ± 12 vs. 8 ± 3/mm2; p < 0.001). However, neither β‐amyloid precursor protein‐immunoreactive dystrophic neurites nor β‐amyloid deposits were found in this tissue. Interleukin‐1α‐immunoreactive cells (microglia) were three times more numerous in epileptics than in controls (80 ± 8 vs. 25 ± 5/mm2; p < 0.001), and these cells were often found adjacent to β‐amyloid precursor protein‐immunoreactive neuronal cell bodies. Our findings, together with functions established in vitro for interleukin‐1, suggest that increased expression of this protein contributes to the increased levels of β‐amyloid precursor protein in epileptics, thus indicating a potential role for both of these proteins in the neuronal dysfunctions, e.g., hyperexcitability, characteristic of epilepsy.