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Sample records for tidally induced brown

  1. Habitability from Tidally Induced Tectonics

    Science.gov (United States)

    Valencia, Diana; Tan, Vivian Yun Yan; Zajac, Zachary

    2018-04-01

    The stability of Earth’s climate on geological timescales is enabled by the carbon–silicate cycle that acts as a negative feedback mechanism stabilizing surface temperatures via the intake and outgassing of atmospheric carbon. On Earth, this thermostat is enabled by plate tectonics that sequesters outgassed CO2 back into the mantle via weathering and subduction at convergent margins. Here we propose a separate tectonic mechanism—vertical recycling—that can serve as the vehicle for CO2 outgassing and sequestration over long timescales. The mechanism requires continuous tidal heating, which makes it particularly relevant to planets in the habitable zone of M stars. Dynamical models of this vertical recycling scenario and stability analysis show that temperate climates stable over timescales of billions of years are realized for a variety of initial conditions, even as the M star dims over time. The magnitude of equilibrium surface temperatures depends on the interplay of sea weathering and outgassing, which in turn depends on planetary carbon content, so that planets with lower carbon budgets are favored for temperate conditions. The habitability of planets such as found in the Trappist-1 system may be rooted in tidally driven tectonics.

  2. Tidal wetland fluxes of dissolved organic carbon and sediment at Browns Island, California: initial evaluation

    Science.gov (United States)

    Ganju, N.K.; Bergamaschi, B.; Schoellhamer, D.H.

    2003-01-01

    Carbon and sediment fluxes from tidal wetlands are of increasing concern in the Sacramento-San Joaquin River Delta (Delta), because of drinking water issues and habitat restoration efforts. Certain forms of dissolved organic carbon (DOC) react with disinfecting chemicals used to treat drinking water, to form disinfection byproducts (DBPs), some of which are potential carcinogens. The contribution of DBP precursors by tidal wetlands is unknown. Sediment transport to and from tidal wetlands determines the potential for marsh accretion, thereby affecting habitat formation.Water, carbon, and sediment flux were measured in the main channel of Browns Island, a tidal wetland located at the confluence of Suisun Bay and the Delta. In-situ instrumentation were deployed between May 3 and May 21, 2002. Water flux was measured using acoustic Doppler current profilers and the index-velocity method. DOC concentrations were measured using calibrated ultraviolet absorbance and fluorescence instruments. Suspended-sediment concentrations were measured using a calibrated nephelometric turbidity sensor. Tidally averaged water flux through the channel was dependent on water surface elevations in Suisun Bay. Strong westerly winds resulted in higher water surface elevations in the area east of Browns Island, causing seaward flow, while subsiding winds reversed this effect. Peak ebb flow transported 36% more water than peak flood flow, indicating an ebb-dominant system. DOC concentrations were affected strongly by porewater drainage from the banks of the channel. Peak DOC concentrations were observed during slack after ebb, when the most porewater drained into the channel. Suspended-sediment concentrations were controlled by tidal currents that mobilized sediment from the channel bed, and stronger tides mobilized more sediment than the weaker tides. Sediment was transported mainly to the island during the 2-week monitoring period, though short periods of export occurred during the spring

  3. Thyroid hormones induce browning of white fat

    Science.gov (United States)

    Martínez-Sánchez, Noelia; Moreno-Navarrete, José M; Contreras, Cristina; Rial-Pensado, Eva; Fernø, Johan; Nogueiras, Rubén; Diéguez, Carlos

    2016-01-01

    The canonical view about the effect of thyroid hormones (THs) on thermogenesis assumes that the hypothalamus acts merely as a modulator of the sympathetic outflow on brown adipose tissue (BAT). Recent data have challenged that vision by demonstrating that THs act on the ventromedial nucleus of the hypothalamus (VMH) to inhibit AMP-activated protein kinase (AMPK), which regulates the thermogenic program in BAT, leading to increased thermogenesis and weight loss. Current data have shown that in addition to activation of brown fat, the browning of white adipose tissue (WAT) might also be an important thermogenic mechanism. However, the possible central effects of THs on the browning of white fat remain unclear. Here, we show that 3,3′,5,5′ tetraiodothyroxyne (T4)-induced hyperthyroidism promotes a marked browning of WAT. Of note, central or VMH-specific administration of 3,3′,5-triiodothyronine (T3) recapitulates that effect. The specific genetic activation of hypothalamic AMPK in the VMH reversed the central effect of T3 on browning. Finally, we also showed that the expression of browning genes in human WAT correlates with serum T4. Overall, these data indicate that THs induce browning of WAT and that this mechanism is mediated via the central effects of THs on energy balance. PMID:27913573

  4. Brown spider dermonecrotic toxin directly induces nephrotoxicity

    International Nuclear Information System (INIS)

    Chaim, Olga Meiri; Sade, Youssef Bacila; Bertoni da Silveira, Rafael; Toma, Leny; Kalapothakis, Evanguedes; Chavez-Olortegui, Carlos; Mangili, Oldemir Carlos; Gremski, Waldemiro; Dietrich, Carl Peter von; Nader, Helena B.; Sanches Veiga, Silvio

    2006-01-01

    Brown spider (Loxosceles genus) venom can induce dermonecrotic lesions at the bite site and systemic manifestations including fever, vomiting, convulsions, disseminated intravascular coagulation, hemolytic anemia and acute renal failure. The venom is composed of a mixture of proteins with several molecules biochemically and biologically well characterized. The mechanism by which the venom induces renal damage is unknown. By using mice exposed to Loxosceles intermedia recombinant dermonecrotic toxin (LiRecDT), we showed direct induction of renal injuries. Microscopic analysis of renal biopsies from dermonecrotic toxin-treated mice showed histological alterations including glomerular edema and tubular necrosis. Hyalinization of tubules with deposition of proteinaceous material in the tubule lumen, tubule epithelial cell vacuoles, tubular edema and epithelial cell lysis was also observed. Leukocytic infiltration was neither observed in the glomerulus nor the tubules. Renal vessels showed no sign of inflammatory response. Additionally, biochemical analyses showed such toxin-induced changes in renal function as urine alkalinization, hematuria and azotemia with elevation of blood urea nitrogen levels. Immunofluorescence with dermonecrotic toxin antibodies and confocal microscopy analysis showed deposition and direct binding of this toxin to renal intrinsic structures. By immunoblotting with a hyperimmune dermonecrotic toxin antiserum on renal lysates from toxin-treated mice, we detected a positive signal at the region of 33-35 kDa, which strengthens the idea that renal failure is directly induced by dermonecrotic toxin. Immunofluorescence reaction with dermonecrotic toxin antibodies revealed deposition and binding of this toxin directly in MDCK epithelial cells in culture. Similarly, dermonecrotic toxin treatment caused morphological alterations of MDCK cells including cytoplasmic vacuoles, blebs, evoked impaired spreading and detached cells from each other and from

  5. Tidally induced lateral dispersion of the Storfjorden overflow plume

    Directory of Open Access Journals (Sweden)

    F. Wobus

    2013-10-01

    Full Text Available We investigate the flow of brine-enriched shelf water from Storfjorden (Svalbard into Fram Strait and onto the western Svalbard Shelf using a regional set-up of NEMO-SHELF, a 3-D numerical ocean circulation model. The model is set up with realistic bathymetry, atmospheric forcing, open boundary conditions and tides. The model has 3 km horizontal resolution and 50 vertical levels in the sh-coordinate system which is specially designed to resolve bottom boundary layer processes. In a series of modelling experiments we focus on the influence of tides on the propagation of the dense water plume by comparing results from tidal and non-tidal model runs. Comparisons of non-tidal to tidal simulations reveal a hotspot of tidally induced horizontal diffusion leading to the lateral dispersion of the plume at the southernmost headland of Spitsbergen which is in close proximity to the plume path. As a result the lighter fractions in the diluted upper layer of the plume are drawn into the shallow coastal current that carries Storfjorden water onto the western Svalbard Shelf, while the dense bottom layer continues to sink down the slope. This bifurcation of the plume into a diluted shelf branch and a dense downslope branch is enhanced by tidally induced shear dispersion at the headland. Tidal effects at the headland are shown to cause a net reduction in the downslope flux of Storfjorden water into the deep Fram Strait. This finding contrasts previous results from observations of a dense plume on a different shelf without abrupt topography.

  6. Second order tidally induced flow in the inlet of a coastal lagoon

    Science.gov (United States)

    Eguiluz, Ana; Wong, Kuo-Chuin

    2005-08-01

    Current meter data obtained in Indian River Inlet and Indian River Bay, Delaware are analyzed to compute second order low-frequency tidal flow and tidally induced mean flow in the system. Results from least-squares harmonic analysis show that nonlinearly induced M4 currents in the inlet and bay occur at order 10 -1 of the M2 amplitudes, indicating weak nonlinearity in the system. Tidally rectified mean flow computed from Mm and Msf is ˜3 cm s -1, which is of the same order of magnitude as the observed mean current. The estimated low-frequency tidal flow and the tidally induced mean flow agree well with scalings computed for the inlet and with results found by Münchow et al. [Münchow, A., Masse, A.K., Garvine, R.W., 1992. Astronomical and nonlinear tidal currents in a coupled estuary shelf system. Continental Shelf Research 12, 471-498] in Delaware Bay.

  7. Clozapine modifies the differentiation program of human adipocytes inducing browning.

    Science.gov (United States)

    Kristóf, E; Doan-Xuan, Q-M; Sárvári, A K; Klusóczki, Á; Fischer-Posovszky, P; Wabitsch, M; Bacso, Z; Bai, P; Balajthy, Z; Fésüs, L

    2016-11-29

    Administration of second-generation antipsychotic drugs (SGAs) often leads to weight gain and consequent cardio-metabolic side effects. We observed that clozapine but not six other antipsychotic drugs reprogrammed the gene expression pattern of differentiating human adipocytes ex vivo, leading to an elevated expression of the browning marker gene UCP1, more and smaller lipid droplets and more mitochondrial DNA than in the untreated white adipocytes. Laser scanning cytometry showed that up to 40% of the differentiating single primary and Simpson-Golabi-Behmel syndrome (SGBS) adipocytes had the characteristic morphological features of browning cells. Furthermore, clozapine significantly upregulated ELOVL3, CIDEA, CYC1, PGC1A and TBX1 genes but not ZIC1 suggesting induction of the beige-like and not the classical brown phenotype. When we tested whether browning induced by clozapine can be explained by its known pharmacological effect of antagonizing serotonin (5HT) receptors, it was found that browning cells expressed 5HT receptors 2A, 1D, 7 and the upregulation of browning markers was diminished in the presence of exogenous 5HT. Undifferentiated progenitors or completely differentiated beige or white adipocytes did not respond to clozapine administration. The clozapine-induced beige cells displayed increased basal and oligomycin-inhibited (proton leak) oxygen consumption, but these cells showed a lower response to cAMP stimulus as compared with control beige adipocytes indicating that they are less capable to respond to natural thermogenic anti-obesity cues. Our data altogether suggest that novel pharmacological stimulation of these masked beige adipocytes can be a future therapeutic target for the treatment of SGA-induced weight gain.

  8. TIDALLY INDUCED OUTBURSTS IN OJ 287 DURING 2005-2008

    International Nuclear Information System (INIS)

    Valtonen, M. J.; Nilsson, K.; Villforth, C.; Lehto, H. J.; Takalo, L. O.; Lindfors, E.; Sillanpaeae, A.; Hentunen, V.-P.; Mikkola, S.; Zola, S.; Drozdz, M.; Ogloza, W.; Winiarski, M.; Koziel, D.; Kurpinska-Winiarska, M.; Siwak, M.; Heidt, J.; Kidger, M.; Pursimo, T.; Wu, J.-H.

    2009-01-01

    The blazar OJ 287 has produced two major optical outburst events during the years 2005-2008. These are the latest in a series of outbursts that have occurred repeatedly at 12 year intervals since early 1900s. It has been possible to explain the historical light curve fairly well by using a binary black hole model where the secondary black hole impacts the accretion disk of the primary twice during the 12 year orbital cycle. We will ask here how well does the latest light-curve fit with this model. We use a 10 million particle disk to model the accretion disk of the primary black hole. The rate of transfer of particles through the 10 Schwarzschild radius cylinder around the primary is followed. The secondary induces an inward flow through this surface. The inward flow rate is compared with the historical light curve as well as with the most recent observations reported in this paper. The observations have been carried out by using a number of small and medium size telescopes in different locations in order to ensure a dense light-curve coverage. The 'inflow light curve' and the optical light curve of OJ 287 have a close resemblance to each other. It suggests that the tidally induced accretion flow is responsible for the main features of the optical light curve, with the exception of the quasi-periodic double peaks. It implies a close connection between the accretion disk and the jet where the optical synchrotron emission is presumably generated.

  9. L-rhamnose induces browning in 3T3-L1 white adipocytes and activates HIB1B brown adipocytes.

    Science.gov (United States)

    Choi, Minji; Mukherjee, Sulagna; Kang, Nam Hyeon; Barkat, Jameel Lone; Parray, Hilal Ahmad; Yun, Jong Won

    2018-04-11

    Induction of the brown adipocyte-like phenotype in white adipocytes (browning) is considered as a novel strategy to fight obesity due to the ability of brown adipocytes to increase energy expenditure. Here, we report that L-rhamnose induced browning by elevating expression levels of beige-specific marker genes, including Cd137, Cited1, Tbx1, Prdm16, Tmem26, and Ucp1, in 3T3-L1 adipocytes. Moreover, L-rhamnose markedly elevated expression levels of proteins involved in thermogenesis both in 3T3-L1 white and HIB1B brown adipocytes. L-rhamnose treatment in 3T3-L1 adipocytes also significantly elevated protein levels of p-HSL, p-AMPK, ACOX, and CPT1 as well as reduced levels of ACC, FAS, C/EBPα, and PPARγ, suggesting its possible role in enhancement of lipolysis and lipid catabolism as well as reduced adipogenesis and lipogenesis, respectively. The quick technique of efficient molecular docking provided insight into the strong binding of L-rhamnose to the fat-digesting glycine residue of β 3 -adrenergic receptor (AR), indicating strong involvement of L-rhamnose in fat metabolism. Further examination of the molecular mechanism of L-rhamnose revealed that it induced browning of 3T3-L1 adipocytes via coordination of multiple signaling pathways through β 3 -AR, SIRT1, PKA, and p-38. To the best of our knowledge, this is the first study to demonstrate that L-rhamnose plays multiple modulatory roles in the induction of white fat browning, activation of brown adipocytes, as well as promotion of lipid metabolism, thereby demonstrating its therapeutic potential for treatment of obesity. © 2018 IUBMB Life, 2018. © 2018 International Union of Biochemistry and Molecular Biology.

  10. Heartbeat Stars and the Ringing of Tidally Induced Pulsations

    OpenAIRE

    Hambleton, K.; Kurtz, D.; Prša, A.; Fuller, J.; Thompson, S.

    2015-01-01

    With the advent of high precision photometry from satellites such as Kepler and CoRoT, a whole new layer of interesting and astounding astronomical objects has been revealed: heartbeat stars are a prime example of such objects. Heartbeat stars are eccentric ellipsoidal variables that undergo strong tidal interactions at the time of closest approach, when the stars are almost in contact. These interactions cause a significant variation in the surface areas of the stars and are observed in the ...

  11. Are neutron stars crushed? Gravitomagnetic tidal fields as a mechanism for binary-induced collapse

    International Nuclear Information System (INIS)

    Favata, Marc

    2006-01-01

    Numerical simulations of binary neutron stars by Wilson, Mathews, and Marronetti indicated that neutron stars that are stable in isolation can be made to collapse to black holes when placed in a binary. This claim was surprising as it ran counter to the Newtonian expectation that a neutron star in a binary should be more stable, not less. After correcting an error found by Flanagan, Wilson and Mathews found that the compression of the neutron stars was significantly reduced but not eliminated. This has motivated us to ask the following general question: Under what circumstances can general-relativistic tidal interactions cause an otherwise stable neutron star to be compressed? We have found that if a nonrotating neutron star possesses a current-quadrupole moment, interactions with a gravitomagnetic tidal field can lead to a compressive force on the star. If this current quadrupole is induced by the gravitomagnetic tidal field, it is related to the tidal field by an equation-of-state-dependent constant called the gravitomagnetic Love number. This is analogous to the Newtonian Love number that relates the strength of a Newtonian tidal field to the induced mass quadrupole moment of a star. The compressive force is almost never larger than the Newtonian tidal interaction that stabilizes the neutron star against collapse. In the case in which a current quadrupole is already present in the star (perhaps as an artifact of a numerical simulation), the compressive force can exceed the stabilizing one, leading to a net increase in the central density of the star. This increase is small (< or approx. 1%) but could, in principle, cause gravitational collapse in a star that is close to its maximum mass. This paper also reviews the history of the Wilson-Mathews-Marronetti controversy and, in an appendix, extends the discussion of tidally induced changes in the central density to rotating stars

  12. TIDALLY INDUCED PULSATIONS IN KEPLER ECLIPSING BINARY KIC 3230227

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Zhao; Gies, Douglas R. [Center for High Angular Resolution Astronomy and Department of Physics and Astronomy, Georgia State University, P.O. Box 5060, Atlanta, GA 30302-5060 (United States); Fuller, Jim, E-mail: guo@astro.gsu.edu, E-mail: gies@chara.gsu.edu, E-mail: jfuller@caltech.edu [TAPIR, Walter Burke Institute for Theoretical Physics, Mailcode 350-17, Caltech, Pasadena, CA 91125 (United States)

    2017-01-01

    KIC 3230227 is a short period (P  ≈ 7.0 days) eclipsing binary with a very eccentric orbit ( e  = 0.6). From combined analysis of radial velocities and Kepler light curves, this system is found to be composed of two A-type stars, with masses of M {sub 1} = 1.84 ± 0.18  M {sub ⊙}, M {sub 2} = 1.73 ± 0.17  M {sub ⊙} and radii of R {sub 1} = 2.01 ± 0.09  R {sub ⊙}, R {sub 2} = 1.68 ± 0.08 R {sub ⊙} for the primary and secondary, respectively. In addition to an eclipse, the binary light curve shows a brightening and dimming near periastron, making this a somewhat rare eclipsing heartbeat star system. After removing the binary light curve model, more than 10 pulsational frequencies are present in the Fourier spectrum of the residuals, and most of them are integer multiples of the orbital frequency. These pulsations are tidally driven, and both the amplitudes and phases are in agreement with predictions from linear tidal theory for l  = 2, m  = −2 prograde modes.

  13. TIDALLY INDUCED PULSATIONS IN KEPLER ECLIPSING BINARY KIC 3230227

    International Nuclear Information System (INIS)

    Guo, Zhao; Gies, Douglas R.; Fuller, Jim

    2017-01-01

    KIC 3230227 is a short period (P  ≈ 7.0 days) eclipsing binary with a very eccentric orbit ( e  = 0.6). From combined analysis of radial velocities and Kepler light curves, this system is found to be composed of two A-type stars, with masses of M 1  = 1.84 ± 0.18  M ⊙ , M 2  = 1.73 ± 0.17  M ⊙ and radii of R 1  = 2.01 ± 0.09  R ⊙ , R 2  = 1.68 ± 0.08 R ⊙ for the primary and secondary, respectively. In addition to an eclipse, the binary light curve shows a brightening and dimming near periastron, making this a somewhat rare eclipsing heartbeat star system. After removing the binary light curve model, more than 10 pulsational frequencies are present in the Fourier spectrum of the residuals, and most of them are integer multiples of the orbital frequency. These pulsations are tidally driven, and both the amplitudes and phases are in agreement with predictions from linear tidal theory for l  = 2, m  = −2 prograde modes.

  14. Wave-induced Maintenance of Suspended Sediment Concentration during Slack in a Tidal Channel on a Sheltered Macro-tidal Flat, Gangwha Island, Korea

    Science.gov (United States)

    Lee, Guan-hong; Kang, KiRyong

    2018-05-01

    A field campaign was conducted to better understand the influence of wave action, in terms of turbulence and bed shear stress, on sediment resuspension and transport processes on a protected tidal flat. An H-frame was deployed in a tidal channel south of Gangwha Island for 6 tidal cycles during November 2006 with instrumentation including an Acoustic Doppler Velocimeter, an Acoustic Backscatter System, and an Optical Backscatter Sensor. During calm conditions, the current-induced shear was dominant and responsible for suspending sediments during the accelerating phases of flood and ebb. During the high-tide slack, both bed shear stress and suspended sediment concentration were reduced. The sediment flux was directed landward due to the scour-lag effect over a tidal cycle. On the other hand, when waves were stronger, the wave-induced turbulence appeared to keep sediments in suspension even during the high-tide slack, while the current-induced shear remained dominant during the accelerating phases of flood and ebb. The sediment flux under strong waves was directed offshore due to the sustained high suspended sediment concentration during the high-tide slack. Although strong waves can induce offshore sediment flux, infrequent events with strong waves are unlikely to alter the long-term accretion of the protected southern Gangwha tidal flats.

  15. Long-term divergent tidal flat benthic community recovery following hypoxia-induced mortality

    NARCIS (Netherlands)

    Colen, van C.; Montserrat, F.; Vincx, M.; Herman, P.M.J.; Ysebaert, T.; Degraer, S.

    2010-01-01

    Macrobenthos recovery after hypoxia-induced mass mortality was assessed in an estuarine tidal mudflat during 3 years. During the first 2 years, a Pearson-Rosenberg type of community recovery took place along with the improving bottom water oxygen conditions. After 3 months, spionid polychaetes

  16. Models of Tidally Induced Gas Filaments in the Magellanic Stream

    Science.gov (United States)

    Pardy, Stephen A.; D’Onghia, Elena; Fox, Andrew J.

    2018-04-01

    The Magellanic Stream and Leading Arm of H I that stretches from the Large and Small Magellanic Clouds (LMC and SMC) and over 200° of the Southern sky is thought to be formed from multiple encounters between the LMC and SMC. In this scenario, most of the gas in the Stream and Leading Arm is stripped from the SMC, yet recent observations have shown a bifurcation of the Trailing Arm that reveals LMC origins for some of the gas. Absorption measurements in the Stream also reveal an order of magnitude more gas than in current tidal models. We present hydrodynamical simulations of the multiple encounters between the LMC and SMC at their first pass around the Milky Way, assuming that the Clouds were more extended and gas-rich in the past. Our models create filamentary structures of gas in the Trailing Stream from both the LMC and SMC. While the SMC trailing filament matches the observed Stream location, the LMC filament is offset. In addition, the total observed mass of the Stream in these models is underestimated by a factor of four when the ionized component is accounted for. Our results suggest that there should also be gas stripped from both the LMC and SMC in the Leading Arm, mirroring the bifurcation in the Trailing Stream. This prediction is consistent with recent measurements of spatial variation in chemical abundances in the Leading Arm, which show that gas from multiple sources is present, although its nature is still uncertain.

  17. Monoterpene limonene induces brown fat-like phenotype in 3T3-L1 white adipocytes.

    Science.gov (United States)

    Lone, Jameel; Yun, Jong Won

    2016-05-15

    Several dietary compounds that are able to induce the brown fat-like phenotype in white adipocytes have been considered for treatment of obesity due to their ability to increase energy expenditure. Here, we report that limonene induces the brown fat-like phenotype in 3T3-L1 adipocytes by increasing expression of brown adipocyte-specific genes and proteins. Limonene-induced browning in white adipocytes was investigated by determining expression levels of brown fat-specific genes and proteins by real-time RT-PCR, immunoblot analysis, and immunocytochemical staining. Limonene enhanced mitochondrial biogenesis, as evidenced by increased mitochondrial content and immunofluorescent intensity. Limonene also significantly elevated protein levels of HSL, PLIN, p-AMPK, p-ACC, ACO, COX4, CPT1, and CYT C, suggesting its possible role in enhancement of lipolysis and lipid catabolism. Increased expression of PRDM16, UCP1, C/EBPβ, and other brown fat-specific markers by limonene was possibly mediated by activation of β3-adnergenic receptor (β3-AR), as inhibition of β3-AR inhibited up-regulation of brown fat-specific markers. Similarly, limonene-mediated activation of ERK and up-regulation of key brown adipocyte specific markers were eliminated by treatment with ERK antagonist. Taken together, these results suggest that limonene induces browning of 3T3-L1 adipocytes via activation of β3-AR and the ERK signaling pathway. In conclusion, our findings suggest that limonene plays a dual modulatory role in induction of the brown adipocyte-like phenotype as well as promotion of lipid metabolism and thus may have potential therapeutic implications for treatment of obesity. Copyright © 2016 Elsevier Inc. All rights reserved.

  18. Low tidal volume ventilation ameliorates left ventricular dysfunction in mechanically ventilated rats following LPS-induced lung injury.

    Science.gov (United States)

    Cherpanath, Thomas G V; Smeding, Lonneke; Hirsch, Alexander; Lagrand, Wim K; Schultz, Marcus J; Groeneveld, A B Johan

    2015-10-07

    High tidal volume ventilation has shown to cause ventilator-induced lung injury (VILI), possibly contributing to concomitant extrapulmonary organ dysfunction. The present study examined whether left ventricular (LV) function is dependent on tidal volume size and whether this effect is augmented during lipopolysaccharide(LPS)-induced lung injury. Twenty male Wistar rats were sedated, paralyzed and then randomized in four groups receiving mechanical ventilation with tidal volumes of 6 ml/kg or 19 ml/kg with or without intrapulmonary administration of LPS. A conductance catheter was placed in the left ventricle to generate pressure-volume loops, which were also obtained within a few seconds of vena cava occlusion to obtain relatively load-independent LV systolic and diastolic function parameters. The end-systolic elastance / effective arterial elastance (Ees/Ea) ratio was used as the primary parameter of LV systolic function with the end-diastolic elastance (Eed) as primary LV diastolic function. Ees/Ea decreased over time in rats receiving LPS (p = 0.045) and high tidal volume ventilation (p = 0.007), with a lower Ees/Ea in the rats with high tidal volume ventilation plus LPS compared to the other groups (p tidal volume ventilation without LPS (p = 0.223). A significant interaction (p tidal ventilation and LPS for Ees/Ea and Eed, and all rats receiving high tidal volume ventilation plus LPS died before the end of the experiment. Low tidal volume ventilation ameliorated LV systolic and diastolic dysfunction while preventing death following LPS-induced lung injury in mechanically ventilated rats. Our data advocates the use of low tidal volumes, not only to avoid VILI, but to avert ventilator-induced myocardial dysfunction as well.

  19. KIC 8164262: a heartbeat star showing tidally induced pulsations with resonant locking

    Science.gov (United States)

    Hambleton, K.; Fuller, J.; Thompson, S.; Prša, A.; Kurtz, D. W.; Shporer, A.; Isaacson, H.; Howard, A. W.; Endl, M.; Cochran, W.; Murphy, S. J.

    2018-02-01

    We present the analysis of KIC 8164262, a heartbeat star with a high-amplitude (∼1 mmag), tidally resonant pulsation (a mode in resonance with the orbit) at 229 times the orbital frequency and a plethora of tidally induced g-mode pulsations (modes excited by the orbit). The analysis combines Kepler light curves with follow-up spectroscopic data from the Keck telescope, KPNO (Kitt Peak National Observatory) 4-m Mayall telescope and the 2.7-m telescope at the McDonald observatory. We apply the binary modelling software, PHOEBE, to the Kepler light curve and radial velocity data to determine a detailed binary star model that includes the prominent pulsation and Doppler boosting, alongside the usual attributes of a binary star model (including tidal distortion and reflection). The results show that the system contains a slightly evolved F star with an M secondary companion in a highly eccentric orbit (e = 0.886). We use the results of the binary star model in a companion paper (Fuller) where we show that the prominent pulsation can be explained by a tidally excited oscillation mode held near resonance by a resonance locking mechanism.

  20. Tidal-Induced Ocean Dynamics as Cause of Enceladus' Tiger Stripe Pattern

    Science.gov (United States)

    Vermeersen, B. L.; Maas, L. R.; van Oers, S.; Rabitti, A.; Jara-Orue, H.

    2013-12-01

    One of the most peculiar features on Saturn moon Enceladus is its so-called tiger stripe pattern at the geologically active South Polar Terrain (SPT), as first observed in detail by the Cassini spacecraft early 2005. It is generally assumed that the four almost parallel surface lines that constitute this pattern are faults in the icy surface overlying a confined salty water reservoir. Indeed, later Cassini observations have shown that salty water jets originate from the tiger stripes [e.g., Hansen et al., Science, 311, 1422-1425, 2006; Postberg et al., Nature, 474, 620-622, 2011]. The periodic activity of the tiger stripe faults shows a strong correlation with tidal forcing. Jets emanating from specific fault lines seem to be triggered at those places of the faults where tidal-induced stresses are largest immediately following closest orbital approach with Saturn [e.g., Hurford et al., Nature, 447, 292-294, 2007]. Thus jet activity seems to be directly induced by tidal forcing. However, this does not explain the characteristic regular pattern of the stripes themselves. Here we explore the possibility that this pattern is formed and maintained by induced, tidally and rotationally driven, fluid motions in the ocean underneath the icy surface of the tiger-stripe region. The remarkable spatial regularity of Enceladus' SPT fault lines is reminiscent of that observed at the surface of confined density-stratified fluids by the action of induced internal gravity waves. Theoretical analysis, numerical simulations and laboratory water tank experiments all indicate that wave attractors - particular limit orbits to which waves are focused in a fluid basin - naturally emerge in gravitationally (radial salt concentration or temperature differences) or rotationally stratified confined fluids as a function of forcing periodicity and fluid basin geometry [Maas et al., Nature, 338, 557-561, 1997]. We have found that ocean dynamical wave attractors induced by tidal-effective forcing

  1. Cellular origins of cold-induced brown adipocytes in adult mice.

    Science.gov (United States)

    Lee, Yun-Hee; Petkova, Anelia P; Konkar, Anish A; Granneman, James G

    2015-01-01

    This work investigated how cold stress induces the appearance of brown adipocytes (BAs) in brown and white adipose tissues (WATs) of adult mice. In interscapular brown adipose tissue (iBAT), cold exposure increased proliferation of endothelial cells and interstitial cells expressing platelet-derived growth factor receptor, α polypeptide (PDGFRα) by 3- to 4-fold. Surprisingly, brown adipogenesis and angiogenesis were largely restricted to the dorsal edge of iBAT. Although cold stress did not increase proliferation in inguinal white adipose tissue (ingWAT), the percentage of BAs, defined as multilocular adipocytes that express uncoupling protein 1, rose from undetectable to 30% of total adipocytes. To trace the origins of cold-induced BAs, we genetically tagged PDGFRα(+) cells and adipocytes prior to cold exposure, using Pdgfra-Cre recombinase estrogen receptor T2 fusion protein (CreER(T2)) and adiponectin-CreER(T2), respectively. In iBAT, cold stress triggered the proliferation and differentiation of PDGFRα(+) cells into BAs. In contrast, all newly observed BAs in ingWAT (5207 out of 5207) were derived from unilocular adipocytes tagged by adiponectin-CreER(T2)-mediated recombination. Surgical denervation of iBAT reduced cold-induced brown adipogenesis by >85%, whereas infusion of norepinephrine (NE) mimicked the effects of cold in warm-adapted mice. NE-induced de novo brown adipogenesis in iBAT was eliminated in mice lacking β1-adrenergic receptors. These observations identify a novel tissue niche for brown adipogenesis in iBAT and further define depot-specific mechanisms of BA recruitment. © FASEB.

  2. Transcription regulator TRIP-Br2 mediates ER stress-induced brown adipocytes dysfunction.

    Science.gov (United States)

    Qiang, Guifen; Whang Kong, Hyerim; Gil, Victoria; Liew, Chong Wee

    2017-01-09

    In contrast to white adipose tissue, brown adipose tissue (BAT) is known to play critical roles for both basal and inducible energy expenditure. Obesity is associated with reduction of BAT function; however, it is not well understood how obesity promotes BAT dysfunction, especially at the molecular level. Here we show that the transcription regulator TRIP-Br2 mediates ER stress-induced inhibition of lipolysis and thermogenesis in BAT. Using in vitro, ex vivo, and in vivo approaches, we demonstrate that obesity-induced inflammation upregulates brown adipocytes TRIP-Br2 expression via the ER stress pathway and amelioration of ER stress in mice completely abolishes high fat diet-induced upregulation of TRIP-Br2 in BAT. We find that increased TRIP-Br2 significantly inhibits brown adipocytes thermogenesis. Finally, we show that ablation of TRIP-Br2 ameliorates ER stress-induced inhibition on lipolysis, fatty acid oxidation, oxidative metabolism, and thermogenesis in brown adipocytes. Taken together, our current study demonstrates a role for TRIP-Br2 in ER stress-induced BAT dysfunction, and inhibiting TRIP-Br2 could be a potential approach for counteracting obesity-induced BAT dysfunction.

  3. Monitoring requirements for detecting tidal barrage induced changes to estuary bird populations

    International Nuclear Information System (INIS)

    Davenport, T.; Jeffers, J.N.R.; North, P.M.; Clark, N.A.; Langston, R.H.W.; Prys-Jones, R.P.

    1990-01-01

    This study was performed to examine the monitoring requirements for detecting tidal barrage induced changes to estuary bird populations, focussing mainly on the Mersey estuary. The degree of variability in populations between years for a number of species within the Mersey, Dee, Alt and Ribble were ascertained. The number of counts needed each winter, before and after barrage construction, were assessed. The percentage charge detectable for species was predicted. One east coast estuary (the Wash) was investigated for comparison of the effects of influences of severe weather. (UK)

  4. Locally Induced Adipose Tissue Browning by Microneedle Patch for Obesity Treatment.

    Science.gov (United States)

    Zhang, Yuqi; Liu, Qiongming; Yu, Jicheng; Yu, Shuangjiang; Wang, Jinqiang; Qiang, Li; Gu, Zhen

    2017-09-26

    Obesity is one of the most serious public health problems in the 21st century that may lead to many comorbidities such as type-2 diabetes, cardiovascular diseases, and cancer. Current treatments toward obesity including diet, physical exercise, pharmacological therapy, as well as surgeries are always associated with low effectiveness or undesired systematical side effects. In order to enhance treatment efficiency with minimized side effects, we developed a transcutaneous browning agent patch to locally induce adipose tissue transformation. This microneedle-based patch can effectively deliver browning agents to the subcutaneous adipocytes in a sustained manner and switch on the "browning" at the targeted region. It is demonstrated that this patch reduces treated fat pad size, increases whole body energy expenditure, and improves type-2 diabetes in vivo in a diet-induced obesity mouse model.

  5. Formation of Tidally Induced Bars in Galactic Flybys: Prograde versus Retrograde Encounters

    Science.gov (United States)

    Łokas, Ewa L.

    2018-04-01

    Bars in disk galaxies can be formed by interactions with other systems, including those of comparable mass. It has long been established that the effect of such interactions on galaxy morphology depends strongly on the orbital configuration, in particular the orientation of the intrinsic spin of the galactic disk with respect to its orbital angular momentum. Prograde encounters modify the morphology strongly, including the formation of tidally induced bars, while retrograde flybys should have little effect on morphology. Recent works on the subject reached conflicting conclusions, one using the impulse approximation and claiming no dependence on this angle in the properties of tidal bars. To resolve the controversy, we performed self-consistent N-body simulations of hyperbolic encounters between two identical Milky Way-like galaxies assuming different velocities and impact parameters, with one of the galaxies on a prograde and the other on a retrograde orbit. The galaxies were initially composed of an exponential stellar disk and an NFW dark halo, and they were stable against bar formation in isolation for 3 Gyr. We find that strong tidally induced bars form only in galaxies on prograde orbits. For smaller impact parameters and lower relative velocities, the bars are stronger and have lower pattern speeds. Stronger bars undergo extended periods of buckling instability that thicken their vertical structure. The encounters also lead to the formation of two-armed spirals with strength inversely proportional to the strength of the bars. We conclude that proper modeling of prograde and retrograde encounters cannot rely on the simplest impulse approximation.

  6. Tidal Pumping-Induced Nutrients Dynamics and Biogeochemical Implications in an Intertidal Aquifer

    Science.gov (United States)

    Liu, Yi; Jiao, Jiu Jimmy; Liang, Wenzhao; Luo, Xin

    2017-12-01

    Tidal pumping is a major driving force affecting water exchange between land and sea, biogeochemical reactions in the intertidal aquifer, and nutrient loading to the sea. At a sandy beach of Tolo Harbour, Hong Kong, the nutrient (NH4+, NO2-, NO3-, and PO43-) dynamic in coastal groundwater mixing zone (CGMZ) is found to be fluctuated with tidal oscillation. Nutrient dynamic is mainly controlled by tidal pumping-induced organic matter that serves as a reagent of remineralization in the aquifer. NH4+, NO2-, and PO43- are positively correlated with salinity. Both NH4+ and PO43- have negative correlations with oxidation/reduction potential. NH4+ is the major dissolved inorganic nitrogen species in CGMZ. The adsorption of PO43- onto iron oxides occurs at the deep transition zone with a salinity of 5-10 practical salinity unit (psu), and intensive N-loss occurs in near-surface area with a salinity of 10-25 psu. The biogeochemical reactions, producing PO43- and consuming NH4+, are synergistic effect of remineralization-nitrification-denitrification. In CGMZ, the annual NH4+ loss is estimated to be 4.32 × 105 mol, while the minimum annual PO43- production is estimated to be 2.55 × 104 mol. Applying these rates to the entire Tolo Harbour, the annual NH4+ input to the harbor through the remineralization of organic matters is estimated to be 1.02 × 107 mol. The annual NH4+ loss via nitrification is 1.32 × 107 mol, and the annual PO43- production is 7.76 × 105 mol.

  7. Cold-Inducible SIRT6 Regulates Thermogenesis of Brown and Beige Fat

    Directory of Open Access Journals (Sweden)

    Lu Yao

    2017-07-01

    Full Text Available Promoting development and function of brown and beige fat may reduce obesity. Here, we show that fat SIRT6 expression is markedly induced by cold exposure and a β-adrenergic agonist. Deletion of SIRT6 in adipose tissue impairs the thermogenic function of brown adipocytes, causing a morphological “whitening” of brown fat, reduced oxygen (O2 consumption, obesity, decreased core body temperature, and cold sensitivity. Fat SIRT6-deleted mice exhibit increased blood glucose levels, severe insulin resistance, and hepatic steatosis. Moreover, SIRT6 deficiency inhibits the browning of white adipose tissue (WAT following cold exposure or β3-agonist treatment. Depletion of SIRT6 expression in brown adipocytes reduces expression of thermogenic genes, causing a reduction in cellular respiration. Conversely, SIRT6 overexpression in primary fat cells stimulates the thermogenic program. Mechanistically, SIRT6 interacts with and promotes phospho-ATF2 binding to the PGC-1α gene promoter to activate its expression. The present study reveals a critical role for SIRT6 in regulating thermogenesis of fat.

  8. The Peroxisome Proliferator-Activated Receptor α is dispensable for cold-induced adipose tissue browning in mice

    NARCIS (Netherlands)

    Defour, Merel; Dijk, Wieneke; Ruppert, Philip; Nascimento, Emmani B.M.; Schrauwen, Patrick; Kersten, Sander

    2018-01-01

    Objective: Chronic cold exposure causes white adipose tissue (WAT) to adopt features of brown adipose tissue (BAT), a process known as browning. Previous studies have hinted at a possible role for the transcription factor Peroxisome Proliferator-Activated Receptor alpha (PPARα) in cold-induced

  9. Brown colour in natural diamond and interaction between the brown related and other colour-inducing defects

    International Nuclear Information System (INIS)

    Fisher, D; Sibley, S J; Kelly, C J

    2009-01-01

    Absorption spectroscopy results on a range of type II diamonds are presented which enable the electronic states associated with them to be mapped out. High pressure, high temperature treatment of brown type IIa diamonds has enabled an activation energy for the removal of the brown colour of 8.0 ± 0.3 eV to be determined and this is consistent with expectations associated with the currently accepted vacancy cluster model for the defect. Theoretical calculations suggest that this defect will generate partially filled gap states about 1 eV above the valence band. Data on the photochromic behaviour of bands producing pink colour and their relation to brown colour are presented; these suggest that the pink bands are produced from two independent transitions with ground states close to each other just below the middle of the band gap. Compensation of neutral boron by charge transfer from states associated with brown colour is demonstrated via the correlated increase in neutral boron and decrease in brown colour on high pressure, high temperature treatment to remove the defects causing the brown colour.

  10. Low Tidal Volume Reduces Lung Inflammation Induced by Liquid Ventilation in Piglets With Severe Lung Injury.

    Science.gov (United States)

    Jiang, Lijun; Feng, Huizhen; Chen, Xiaofan; Liang, Kaifeng; Ni, Chengyao

    2017-05-01

    Total liquid ventilation (TLV) is an alternative treatment for severe lung injury. High tidal volume is usually required for TLV to maintain adequate CO 2 clearance. However, high tidal volume may cause alveolar barotrauma. We aim to investigate the effect of low tidal volume on pulmonary inflammation in piglets with lung injury and under TLV. After the establishment of acute lung injury model by infusing lipopolysaccharide, 12 piglets were randomly divided into two groups, TLV with high tidal volume (25 mL/kg) or with low tidal volume (6 mL/kg) for 240 min, respectively. Extracorporeal CO 2 removal was applied in low tidal volume group to improve CO 2 clearance and in high tidal volume group as sham control. Gas exchange and hemodynamic status were monitored every 30 min during TLV. At the end of the study, pulmonary mRNA expression and plasmatic concentration of interleukin-6 (IL-6) and interleukin-8 (IL-8) were measured by collecting lung tissue and blood samples from piglets. Arterial blood pressure, PaO 2 , and PaCO 2 showed no remarkable difference between groups during the observation period. Compared with high tidal volume strategy, low tidal volume resulted in 76% reduction of minute volume and over 80% reduction in peak inspiratory pressure during TLV. In addition, low tidal volume significantly diminished pulmonary mRNA expression and plasmatic level of IL-6 and IL-8. We conclude that during TLV, low tidal volume reduces lung inflammation in piglets with acute lung injury without compromising gas exchange. © 2016 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

  11. Environmental change on tidal flat induced by anthropogenic effect around west coast of Korean Peninsula

    Science.gov (United States)

    Lee, Yoon-Kyung; Choi, Jong-Kuk; Ryu, Joo-Hyung; Eom, Jinah

    2014-05-01

    Tidal flats are valuable ecosystem by a productive flora and fauna which support large populations of birds, form nursery and feeding areas for coastal fisheries, provide intrinsic values such as aesthetics and education (Costanza et al., 1997; Goodwin et al., 2001). The half of the world's coastal wetlands will submerge during this century in response to sea level rise although salt marsh has a capacity to adjust to sea level rise change. However, tidal flats have been changed because of several coastal construction projects that had not been considered sustainable over the last 30 years in Korean Peninsula. The total area of tidal flats decreased from approximately 2,800 km2 in 1990 to 2,393 km2 in 2005 due to the land reclamations and dredging in South Korea. Many researchers investigated topography, sedimentation changes and local hydrodynamics for this area in the early 1990s. However, they are limited to the temporal and spatial scale because field surveys in the tidal flats are restricted due to the difficulties in accessing. The aim of this study was to examine environmental change in tidal flat in a large scale for long-term based on the remotely sensed data as well as in situ measurements. This study focused on the tidal flat that not only had been affected by reclamations on a large scale such as Ganghwa and Saemangeum but also had been indirectly affected by reclamations such as Hwang-do and Gomso-bay. In this study, changes in morphology and sedimentary facies in tidal flats were estimated. Digital elevation models (DEMs) in early 2000 and 2010 were generated based on the Landsat TM/ETM+ images using a waterline method. Morphological change was estimated based on the differences of DEMs and sedimentary facies was investigated based on the calculation of image-derived PCA coefficient. Results of the morphological change in tidal flats interestingly showed that large amount of areas had been deposited whereas the other areas were eroded. Area with

  12. Cold Exposure Induces Proliferation of Mature Brown Adipocyte in a ß3-Adrenergic Receptor-Mediated Pathway.

    Science.gov (United States)

    Fukano, Keigo; Okamatsu-Ogura, Yuko; Tsubota, Ayumi; Nio-Kobayashi, Junko; Kimura, Kazuhiro

    2016-01-01

    Hyperplasia of brown adipose tissue (BAT) is a fundamental mechanism for adaptation to survive in the cold environment in rodents. To determine which cell types comprising BAT contribute to tissue hyperplasia, immunohistochemical analysis using a proliferative marker Ki67 was performed on the BAT from 6-week-old C57BL/6J mice housed at 23°C (control) or 10°C (cold) for 5 days. Interestingly, in the control group, the cell proliferative marker Ki67 was detected in the nuclei of uncoupling protein 1-positive mature brown adipocytes (7.2% ± 0.4% of brown adipocyte), as well as in the non-adipocyte stromal-vascular (SV) cells (19.6% ± 2.3% of SV cells), which include preadiopocytes. The percentage of Ki67-positive brown adipocytes increased to 25.6% ± 1.8% at Day 1 after cold exposure and was significantly higher than the non-cold acclimated control until Day 5 (21.8% ± 1.7%). On the other hand, the percentage of Ki67-positive SV cells gradually increased by a cold exposure and peaked to 42.1% ± 8.3% at Day 5. Injection of a ß3-adrenergic receptor (ß3-AR) agonist for continuous 5 days increased the number of Ki67-positive brown adipocytes even at Day 1 but not that of SV cells. In addition, the ß3-AR antagonist, but not ß1-AR antagonist, attenuated the cold exposure-induced increase in the number of Ki67-positive brown adipocytes. These results suggest that mature brown adipocytes proliferate immediately after cold exposure in a ß3-AR-mediated pathway. Thus, proliferation of mature brown adipocytes as well as preadipocytes in SV cells may contribute to cold exposure-induced BAT hyperplasia.

  13. Caloric restriction and diet-induced weight loss do not induce browning of human subcutaneous white adipose tissue in women and men with obesity

    DEFF Research Database (Denmark)

    Barquissau, Valentin; Léger, Benjamin; Beuzelin, Diane

    2018-01-01

    Caloric restriction (CR) is standard lifestyle therapy in obesity management. CR-induced weight loss improves the metabolic profile of individuals with obesity. In mice, occurrence of beige fat cells in white fat depots favors a metabolically healthy phenotype, and CR promotes browning of white...... variation, with higher expression of brown and beige markers in women with obesity and during winter, respectively. The very low calorie diet resulted in decreased browning of subcutaneous abdominal WAT. During the whole dietary intervention, evolution of body fat and insulin resistance was independent...

  14. Physiological evidence for a human-induced landscape of fear in brown bears (Ursus arctos).

    Science.gov (United States)

    Støen, Ole-Gunnar; Ordiz, Andres; Evans, Alina L; Laske, Timothy G; Kindberg, Jonas; Fröbert, Ole; Swenson, Jon E; Arnemo, Jon M

    2015-12-01

    Human persecution is a major cause of mortality for large carnivores. Consequently, large carnivores avoid humans, but may use human-dominated landscapes by being nocturnal and elusive. Behavioral studies indicate that certain ecological systems are "landscapes of fear", driven by antipredator behavior. Because behavior and physiology are closely interrelated, physiological assessments may provide insight into the behavioral response of large carnivores to human activity. To elucidate changes in brown bears' (Ursus arctos) behavior associated with human activity, we evaluated stress as changes in heart rate (HR) and heart rate variability (HRV) in 12 GPS-collared, free-ranging bears, 7 males and 5 females, 3-11 years old, using cardiac-monitoring devices. We applied generalized linear regression models with HR and HRV as response variables and chest activity, time of day, season, distance traveled, and distance to human settlements from GPS positions recorded every 30 min as potential explanatory variables. Bears exhibited lower HRV, an indication of stress, when they were close to human settlements and especially during the berry season, when humans were more often in the forest, picking berries and hunting. Our findings provide evidence of a human-induced landscape of fear in this hunted population of brown bears. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

  15. Ambient particulate air pollution induces oxidative stress and alterations of mitochondria and gene expression in brown and white adipose tissues

    Directory of Open Access Journals (Sweden)

    Harkema Jack R

    2011-07-01

    Full Text Available Abstract Background Prior studies have demonstrated a link between air pollution and metabolic diseases such as type II diabetes. Changes in adipose tissue and its mitochondrial content/function are closely associated with the development of insulin resistance and attendant metabolic complications. We investigated changes in adipose tissue structure and function in brown and white adipose depots in response to chronic ambient air pollutant exposure in a rodent model. Methods Male ApoE knockout (ApoE-/- mice inhaled concentrated fine ambient PM (PM 2.5 or filtered air (FA for 6 hours/day, 5 days/week, for 2 months. We examined superoxide production by dihydroethidium staining; inflammatory responses by immunohistochemistry; and changes in white and brown adipocyte-specific gene profiles by real-time PCR and mitochondria by transmission electron microscopy in response to PM2.5 exposure in different adipose depots of ApoE-/- mice to understand responses to chronic inhalational stimuli. Results Exposure to PM2.5 induced an increase in the production of reactive oxygen species (ROS in brown adipose depots. Additionally, exposure to PM2.5 decreased expression of uncoupling protein 1 in brown adipose tissue as measured by immunohistochemistry and Western blot. Mitochondrial number was significantly reduced in white (WAT and brown adipose tissues (BAT, while mitochondrial size was also reduced in BAT. In BAT, PM2.5 exposure down-regulated brown adipocyte-specific genes, while white adipocyte-specific genes were differentially up-regulated. Conclusions PM2.5 exposure triggers oxidative stress in BAT, and results in key alterations in mitochondrial gene expression and mitochondrial alterations that are pronounced in BAT. We postulate that exposure to PM2.5 may induce imbalance between white and brown adipose tissue functionality and thereby predispose to metabolic dysfunction.

  16. Frequent extreme cold exposure and brown fat and cold-induced thermogenesis: A study in a monozygotic twin

    NARCIS (Netherlands)

    M.J. Vosselman (Maarten J.); G.H.E.J. Vijgen (Guy H. E. J.); B.R.M. Kingma (Boris R. M.); B. Brans (Boudewijn); W.D. Van Marken Lichtenbelt (Wouter D.)

    2014-01-01

    textabstractIntroduction: Mild cold acclimation is known to increase brown adipose tissue (BAT) activity and cold-induced thermogenesis (CIT) in humans. We here tested the effect of a lifestyle with frequent exposure to extreme cold on BAT and CIT in a Dutch man known as 'the Iceman', who has

  17. Matured Hop Bittering Components Induce Thermogenesis in Brown Adipose Tissue via Sympathetic Nerve Activity.

    Directory of Open Access Journals (Sweden)

    Yumie Morimoto-Kobayashi

    Full Text Available Obesity is the principal symptom of metabolic syndrome, which refers to a group of risk factors that increase the likelihood of atherosclerosis. In recent decades there has been a sharp rise in the incidence of obesity throughout the developed world. Iso-α-acids, the bitter compounds derived from hops in beer, have been shown to prevent diet-induced obesity by increasing lipid oxidation in the liver and inhibition of lipid absorption from the intestine. Whereas the sharp bitterness induced by effective dose of iso-α-acids precludes their acceptance as a nutrient, matured hop bittering components (MHB appear to be more agreeable. Therefore, we tested MHB for an effect on ameliorating diet-induced body fat accumulation in rodents. MHB ingestion had a beneficial effect but, compared to iso-α-acids and despite containing structurally similar compounds, acted via different mechanisms to reduce body fat accumulation. MHB supplementation significantly reduced body weight gain, epididymal white adipose tissue weight, and plasma non-esterified free fatty acid levels in diet-induced obese mice. We also found that uncoupling protein 1 (UCP1 expression in brown adipose tissue (BAT was significantly increased in MHB-fed mice at both the mRNA and protein levels. In addition, MHB administration in rats induced the β-adrenergic signaling cascade, which is related to cAMP accumulation in BAT, suggesting that MHB could modulate sympathetic nerve activity innervating BAT (BAT-SNA. Indeed, single oral administration of MHB elevated BAT-SNA in rats, and this elevation was dissipated by subdiaphragmatic vagotomy. Single oral administration of MHB maintained BAT temperature at a significantly higher level than in control rats. Taken together, these findings indicate that MHB ameliorates diet-induced body fat accumulation, at least partly, by enhancing thermogenesis in BAT via BAT-SNA activation. Our data suggests that MHB is a useful tool for developing functional

  18. Tidal-Induced Internal Ocean Waves as an Explanation for Enceladus' Tiger Stripe Pattern and Hotspot Activity

    Science.gov (United States)

    Vermeersen, B. L. A.; Maas, L. R.; van Oers, S.; Rabitti, A.; Jara-Orue, H.

    2014-12-01

    One of the most peculiar features on Saturn moon Enceladus is its so-called tiger stripe pattern at the geologically active South Polar Terrain (SPT), as first observed in detail by the Cassini spacecraft early 2005. It is generally assumed that the four almost parallel surface lines that constitute this pattern are faults in the icy surface overlying a confined salty water reservoir. Indeed, later Cassini observations have shown that salty water jets originate from the tiger stripes [e.g., Hansen et al., Science, 311, 1422-1425, 2006; Postberg et al., Nature, 474, 620-622, 2011]. More recently, Porco et al. [Astron. J., 148:45, Sep. 2014] and Nimmo et al. [Astron. J., 148:46, Sep. 2014] have reported strong evidence that the geysers are not caused by frictional heating at the surface, but that geysers must originate deeper in Enceladus' interior. Tidal flexing models, like those of Hurford et al., Nature, 447, 292-294, 2007, give a good match for the brightness variations Cassini observes, but they seem to fail to reproduce the exact timing of plume brightening. Although jet activity is thus strongly connected to tidal forcing, another mechanism must be involved as well. Last year, we formulated the original idea [Vermeersen et al., AGU Fall Meeting 2013, abstract #P53B-1848] that the tiger stripe pattern is formed and maintained by induced, tidally and rotationally driven, wave-attractor motions in the ocean underneath the icy surface of the tiger-stripe region. Such wave-attractor motions are observed in water tank experiments in laboratories on Earth and in numerical experiments [Maas et al., Nature, 338, 557-561, 1997; Drijfhout and Maas, J. Phys. Oceanogr., 37, 2740-2763, 2007; Hazewinkel et al., Phys. Fluids, 22, 107102, 2010]. The latest observations by Porco et al. and Nimmo et al. seem to be in agreement with this tidal-induced wave attractor phenomenon, both with respect to tiger stripe pattern and with respect to timing of hotspot activity. However, in

  19. Functional brown adipose tissue limits cardiomyocyte injury and adverse remodeling in catecholamine-induced cardiomyopathy.

    Science.gov (United States)

    Thoonen, Robrecht; Ernande, Laura; Cheng, Juan; Nagasaka, Yasuko; Yao, Vincent; Miranda-Bezerra, Alexandre; Chen, Chan; Chao, Wei; Panagia, Marcello; Sosnovik, David E; Puppala, Dheeraj; Armoundas, Antonis A; Hindle, Allyson; Bloch, Kenneth D; Buys, Emmanuel S; Scherrer-Crosbie, Marielle

    2015-07-01

    Brown adipose tissue (BAT) has well recognized thermogenic properties mediated by uncoupling protein 1 (UCP1); more recently, BAT has been demonstrated to modulate cardiovascular risk factors. To investigate whether BAT also affects myocardial injury and remodeling, UCP1-deficient (UCP1(-/-)) mice, which have dysfunctional BAT, were subjected to catecholamine-induced cardiomyopathy. At baseline, there were no differences in echocardiographic parameters, plasma cardiac troponin I (cTnI) or myocardial fibrosis between wild-type (WT) and UCP1(-/-) mice. Isoproterenol infusion increased cTnI and myocardial fibrosis and induced left ventricular (LV) hypertrophy in both WT and UCP1(-/-) mice. UCP1(-/-) mice also demonstrated exaggerated myocardial injury, fibrosis, and adverse remodeling, as well as decreased survival. Transplantation of WT BAT to UCP1(-/-) mice prevented the isoproterenol-induced cTnI increase and improved survival, whereas UCP1(-/-) BAT transplanted to either UCP1(-/-) or WT mice had no effect on cTnI release. After 3 days of isoproterenol treatment, phosphorylated AKT and ERK were lower in the LV's of UCP1(-/-) mice than in those of WT mice. Activation of BAT was also noted in a model of chronic ischemic cardiomyopathy, and was correlated to LV dysfunction. Deficiency in UCP1, and accompanying BAT dysfunction, increases cardiomyocyte injury and adverse LV remodeling, and decreases survival in a mouse model of catecholamine-induced cardiomyopathy. Myocardial injury and decreased survival are rescued by transplantation of functional BAT to UCP1(-/-) mice, suggesting a systemic cardioprotective role of functional BAT. BAT is also activated in chronic ischemic cardiomyopathy. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. Hypoxic Stress Upregulates the Expression of Slc38a1 in Brown Adipocytes via Hypoxia-Inducible Factor-1α.

    Science.gov (United States)

    Horie, Tetsuhiro; Fukasawa, Kazuya; Iezaki, Takashi; Park, Gyujin; Onishi, Yuki; Ozaki, Kakeru; Kanayama, Takashi; Hiraiwa, Manami; Kitaguchi, Yuka; Kaneda, Katsuyuki; Hinoi, Eiichi

    2018-01-01

    The availability of amino acid in the brown adipose tissue (BAT) has been shown to be altered under various conditions; however, little is known about the possible expression and pivotal role of amino acid transporters in BAT under physiological and pathological conditions. The present study comprehensively investigated whether amino acid transporters are regulated by obesogenic conditions in BAT in vivo. Moreover, we investigated the mechanism underlying the regulation of the expression of amino acid transporters by various stressors in brown adipocytes in vitro. The expression of solute carrier family 38 member 1 (Slc38a1; gene encoding sodium-coupled neutral amino acid transporter 1) was preferentially upregulated in the BAT of both genetic and acquired obesity mice in vivo. Moreover, the expression of Slc38a1 was induced by hypoxic stress through hypoxia-inducible factor-1α, which is a master transcription factor of the adaptive response to hypoxic stress, in brown adipocytes in vitro. These results indicate that Slc38a1 is an obesity-associated gene in BAT and a hypoxia-responsive gene in brown adipocytes. © 2017 S. Karger AG, Basel.

  1. Caloric Restriction and Diet-Induced Weight Loss Do Not Induce Browning of Human Subcutaneous White Adipose Tissue in Women and Men with Obesity.

    Science.gov (United States)

    Barquissau, Valentin; Léger, Benjamin; Beuzelin, Diane; Martins, Frédéric; Amri, Ez-Zoubir; Pisani, Didier F; Saris, Wim H M; Astrup, Arne; Maoret, Jean-José; Iacovoni, Jason; Déjean, Sébastien; Moro, Cédric; Viguerie, Nathalie; Langin, Dominique

    2018-01-23

    Caloric restriction (CR) is standard lifestyle therapy in obesity management. CR-induced weight loss improves the metabolic profile of individuals with obesity. In mice, occurrence of beige fat cells in white fat depots favors a metabolically healthy phenotype, and CR promotes browning of white adipose tissue (WAT). Here, human subcutaneous abdominal WAT samples were analyzed in 289 individuals with obesity following a two-phase dietary intervention consisting of an 8 week very low calorie diet and a 6-month weight-maintenance phase. Before the intervention, we show sex differences and seasonal variation, with higher expression of brown and beige markers in women with obesity and during winter, respectively. The very low calorie diet resulted in decreased browning of subcutaneous abdominal WAT. During the whole dietary intervention, evolution of body fat and insulin resistance was independent of changes in brown and beige fat markers. These data suggest that diet-induced effects on body fat and insulin resistance are independent of subcutaneous abdominal WAT browning in people with obesity. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

  2. Caloric Restriction and Diet-Induced Weight Loss Do Not Induce Browning of Human Subcutaneous White Adipose Tissue in Women and Men with Obesity

    Directory of Open Access Journals (Sweden)

    Valentin Barquissau

    2018-01-01

    Full Text Available Caloric restriction (CR is standard lifestyle therapy in obesity management. CR-induced weight loss improves the metabolic profile of individuals with obesity. In mice, occurrence of beige fat cells in white fat depots favors a metabolically healthy phenotype, and CR promotes browning of white adipose tissue (WAT. Here, human subcutaneous abdominal WAT samples were analyzed in 289 individuals with obesity following a two-phase dietary intervention consisting of an 8 week very low calorie diet and a 6-month weight-maintenance phase. Before the intervention, we show sex differences and seasonal variation, with higher expression of brown and beige markers in women with obesity and during winter, respectively. The very low calorie diet resulted in decreased browning of subcutaneous abdominal WAT. During the whole dietary intervention, evolution of body fat and insulin resistance was independent of changes in brown and beige fat markers. These data suggest that diet-induced effects on body fat and insulin resistance are independent of subcutaneous abdominal WAT browning in people with obesity.

  3. Herbivory-induced glucose transporter gene expression in the brown planthopper, Nilaparvata lugens.

    Science.gov (United States)

    Kikuta, Shingo; Nakamura, Yuki; Hattori, Makoto; Sato, Ryoichi; Kikawada, Takahiro; Noda, Hiroaki

    2015-09-01

    Nilaparvata lugens, the brown planthopper (BPH) feeds on rice phloem sap, containing high amounts of sucrose as a carbon source. Nutrients such as sugars in the digestive tract are incorporated into the body cavity via transporters with substrate selectivity. Eighteen sugar transporter genes of BPH (Nlst) were reported and three transporters have been functionally characterized. However, individual characteristics of NlST members associated with sugar transport remain poorly understood. Comparative gene expression analyses using oligo-microarray and quantitative RT-PCR revealed that the sugar transporter gene Nlst16 was markedly up-regulated during BPH feeding. Expression of Nlst16 was induced 2 h after BPH feeding on rice plants. Nlst16, mainly expressed in the midgut, appears to be involved in carbohydrate incorporation from the gut cavity into the hemolymph. Nlst1 (NlHT1), the most highly expressed sugar transporter gene in the midgut was not up-regulated during BPH feeding. The biochemical function of NlST16 was shown as facilitative glucose transport along gradients. Glucose uptake activity by NlST16 was higher than that of NlST1 in the Xenopus oocyte expression system. At least two NlST members are responsible for glucose uptake in the BPH midgut, suggesting that the midgut of BPH is equipped with various types of transporters having diversified manner for sugar uptake. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Formation of S-type planets in close binaries: scattering induced tidal capture of circumbinary planets

    Science.gov (United States)

    Gong, Yan-Xiang; Ji, Jianghui

    2018-05-01

    Although several S-type and P-type planets in binary systems were discovered in past years, S-type planets have not yet been found in close binaries with an orbital separation not more than 5 au. Recent studies suggest that S-type planets in close binaries may be detected through high-accuracy observations. However, nowadays planet formation theories imply that it is difficult for S-type planets in close binaries systems to form in situ. In this work, we extensively perform numerical simulations to explore scenarios of planet-planet scattering among circumbinary planets and subsequent tidal capture in various binary configurations, to examine whether the mechanism can play a part in producing such kind of planets. Our results show that this mechanism is robust. The maximum capture probability is ˜10%, which can be comparable to the tidal capture probability of hot Jupiters in single star systems. The capture probability is related to binary configurations, where a smaller eccentricity or a low mass ratio of the binary will lead to a larger probability of capture, and vice versa. Furthermore, we find that S-type planets with retrograde orbits can be naturally produced via capture process. These planets on retrograde orbits can help us distinguish in situ formation and post-capture origin for S-type planet in close binaries systems. The forthcoming missions (PLATO) will provide the opportunity and feasibility to detect such planets. Our work provides several suggestions for selecting target binaries in search for S-type planets in the near future.

  5. Tidal power

    International Nuclear Information System (INIS)

    Baker, A.C.

    1991-01-01

    This book describes how large tides develop in particular places and how the energy could be extracted by building suitable barrages. The principal features of a barrage and possible methods of operation are described in detail. Although a tidal power barrage would be non-polluting, the resulting changes in the tidal regime would have important environmental effects. These are discussed together with the economics of tidal power. Methods of assessing the likely cost of electricity from any site are set out and applied to possible sites around the world. (author)

  6. Cold exposure rapidly induces virtual saturation of brown adipose tissue nuclear T3 receptors

    International Nuclear Information System (INIS)

    Bianco, A.C.; Silva, J.E.

    1988-01-01

    Cold exposure induces a rapid increase in uncoupling protein (UCP) concentration in the brown adipose tissue (BAT) of euthyroid, but not hypothyroid, rats. To normalize this response with exogenous 3,5,3'-triiodothyronine (T 3 ), it is necessary to cause systemic hyperthyroidism. In contrast, the same result can be obtained with just replacement doses of thyroxine (T 4 ) and, in euthyroid rats, the normal response of UCP to cold occurs without hyperthyroid plasma T 3 levels. Consequently, the authors explored the possibility that the cold-induced activation of the type II 5'-deiodinase resulted in high levels of nuclear T 3 receptor occupancy in euthyroid rats. Studies were performed with pulse injections of tracer T 3 or T 4 in rats exposed to 4 degree C for different lengths of time (1 h-3 wk). Within 4 h of cold exposure, they observed a significant increase in the nuclear [ 125 I]T 3 derived from the tracer [ 125 I]T 4 injections (T 3 [T 4 ]) and a significant reduction in the nuclear [ 125 I]T 3 derived from [ 125 I]T 3 injections (T 3 [T 3 ]). The number of BAT nuclear T 3 receptors did not increase for up to 3 wk of observation at 4 degree C. The mass of nuclear-bound T 3 was calculated from the nuclear tracer [ 125 I]T 3 [T 3 ] and [ 125 I]T 3 [T 4 ] at equilibrium and the specific activity of serum T 3 and T 4 , respectively. By 4 h after the initiation of the cold exposure, the receptors were >95% occupied and remained so for the 3 weeks of observation. They conclude that the simultaneous activation of the deiodinase with adrenergic BAT stimulation serves the purpose of nearly saturating the nuclear T 3 receptors. This makes possible the realization of the full thermogenic potential of the tissue without causing systemic hyperthyroidism

  7. Neuroprotective Effects of Germinated Brown Rice in Rotenone-Induced Parkinson's-Like Disease Rats.

    Science.gov (United States)

    Chompoopong, Supin; Jarungjitaree, Sunit; Punbanlaem, Tideeporn; Rungruang, Thanaporn; Chongthammakun, Sukumal; Kettawan, Aikkarach; Taechowisan, Thongchai

    2016-09-01

    The effects of germinated brown rice (GBR) on the motor deficits and the dopaminergic (DA) cell death were investigated in Parkinson's-like disease (PD) rats. Reactive oxidative species generated by chronic subcutaneous injection of rotenone (RT) lead to neuronal apoptosis particularly in the nigrostriatal DA system and produce many features of PD, bradykinesis, postural instability and rigidity. In this study, 4-phenylbutyric acid (4-PBA), previously reported to inhibit RT-induced DA cell death, was used as the positive control. Results show that pretreatment with GBR as well as 4-PBA significantly enhanced the motor activity after RT injection, and GBR affected significantly in open field test, only in the ambulation but not the mobility duration, and ameliorated the time to orient down (t-turn) and total time to descend the pole (t-total) in pole test as compared to RT group, but significantly lowered both t-turn and t-total only in 4-PBA group. The percentage of apoptotic cells in brain measured by flow cytometry and the inflammatory effect measured by ELISA of TNF-α showed significant increase in RT group as compared to the control (CT) group at P < 0.05. Apoptotic cells in RT group (85.98 %) showed a significant (P < 0.05) increase versus CT group (17.50 %), and this effect was attenuated in GBR+RT group by decreasing apoptotic cells (79.32 %), whereas, increased viable cells (17.94 %) versus RT group (10.79 %). GBR in GBR + RT group could decrease TNF-α both in the serum and in brain. In summary, GBR showed a neuroprotective effect in RT-induced PD rats, and it may be useful as a value-added functional food to prevent neurodegenerative disease or PD.

  8. Tidal radiation

    International Nuclear Information System (INIS)

    Mashhoon, B.

    1977-01-01

    The general theory of tides is developed within the framework of Einstein's theory of gravitation. It is based on the concept of Fermi frame and the associated notion of tidal frame along an open curve in spacetime. Following the previous work of the author an approximate scheme for the evaluation of tidal gravitational radiation is presented which is valid for weak gravitational fields. The emission of gravitational radiation from a body in the field of a black hole is discussed, and for some cases of astrophysical interest estimates are given for the contributions of radiation due to center-of-mass motion, purely tidal deformation, and the interference between the center of mass and tidal motions

  9. Role of bronchodilation and pattern of breathing in increasing tidal expiratory flow with progressive induced hypercapnia in chronic obstructive pulmonary disease.

    Science.gov (United States)

    Finucane, Kevin E; Singh, Bhajan

    2018-01-01

    Hypercapnia (HC) in vitro relaxes airway smooth muscle; in vivo, it increases respiratory effort, tidal expiratory flows (V̇ exp ), and, by decreasing inspiratory duration (Ti), increases elastic recoil pressure (Pel) via lung viscoelasticity; however, its effect on airway resistance is uncertain. We examined the contributions of bronchodilation, Ti, and expiratory effort to increasing V̇ exp with progressive HC in 10 subjects with chronic obstructive pulmonary disease (COPD): mean forced expiratory volume in 1 s (FEV 1 ) 53% predicted. Lung volumes (Vl), V̇ exp , esophageal pressure (Pes), Ti, and end-tidal Pco 2 ([Formula: see text]) were measured during six tidal breaths followed by an inspiratory capacity (IC), breathing air, and at three levels of HC. V̇ exp and V̇ with submaximal forced vital capacities breathing air (V̇ sFVC ) were compared. Pulmonary resistance ( Rl) was measured from the Pes-V̇ relationship. V̇ exp and Pes at end-expiratory lung volume (EELV) + 0.3 tidal volume [V̇ (0.3Vt) and Pes (0.3Vt) , respectively], Ti, and Rl correlated with [Formula: see text] ( P pulmonary disease (COPD), progressive HC increases tidal expiratory flows by inducing bronchodilation and via an increased rate of inspiration and lung viscoelasticity, a probable increase in lung elastic recoil pressure, both changes increasing expiratory flows, promoting lung emptying and a stable end-expiratory volume. Bronchodilation with HC occurred despite optimal standard bronchodilator therapy, suggesting that in COPD further bronchodilation is possible.

  10. Tidal energy

    International Nuclear Information System (INIS)

    Lochte, H.G.

    1995-01-01

    Together with wave energy, ocean thermal energy, and the often overlooked energy from ocean curents tidal energy belongs to those renewable energy sources that can be subsumed under the generic term of ocean energy. All that these energy sources have in common, however, is that they are found in the ocean. The present article discusses tidal energy with respect to the four principal factors determining the scope of a renewable energy source, namely global, technical, and economic availability and ecological acceptability. (orig.) [de

  11. Infrared rotational light curves on Jupiter induced by wave activities and cloud patterns andimplications on brown dwarfs

    Science.gov (United States)

    Ge, Huazhi; Zhang, Xi; Fletcher, Leigh; Orton, Glenn S.; Sinclair, James Andrew; Fernandes,, Joshua; Momary, Thomas W.; Warren, Ari; Kasaba, Yasumasa; Sato, Takao M.; Fujiyoshi, Takuya

    2017-10-01

    Many brown dwarfs exhibit infrared rotational light curves with amplitude varying from a fewpercent to twenty percent (Artigau et al. 2009, ApJ, 701, 1534; Radigan et al. 2012, ApJ, 750,105). Recently, it was claimed that weather patterns, especially planetary-scale waves in thebelts and cloud spots, are responsible for the light curves and their evolutions on brown dwarfs(Apai et al. 2017, Science, 357, 683). Here we present a clear relationship between the direct IRemission maps and light curves of Jupiter at multiple wavelengths, which might be similar withthat on cold brown dwarfs. Based on infrared disk maps from Subaru/COMICS and VLT/VISIR,we constructed full maps of Jupiter and rotational light curves at different wavelengths in thethermal infrared. We discovered a strong relationship between the light curves and weatherpatterns on Jupiter. The light curves also exhibit strong multi-bands phase shifts and temporalvariations, similar to that detected on brown dwarfs. Together with the spectra fromTEXES/IRTF, our observations further provide detailed information of the spatial variations oftemperature, ammonia clouds and aerosols in the troposphere of Jupiter (Fletcher et al. 2016,Icarus, 2016 128) and their influences on the shapes of the light curves. We conclude that waveactivities in Jupiter’s belts (Fletcher et al. 2017, GRL, 44, 7140), cloud holes, and long-livedvortices such as the Great Red Spot and ovals control the shapes of IR light curves and multi-wavelength phase shifts on Jupiter. Our finding supports the hypothesis that observed lightcurves on brown dwarfs are induced by planetary-scale waves and cloud spots.

  12. Ozone induces glucose intolerance and systemic metabolic effects in young and aged brown Norway rats

    International Nuclear Information System (INIS)

    Bass, V.; Gordon, C.J.; Jarema, K.A.; MacPhail, R.C.; Cascio, W.E.; Phillips, P.M.; Ledbetter, A.D.; Schladweiler, M.C.; Andrews, D.; Miller, D.; Doerfler, D.L.; Kodavanti, U.P.

    2013-01-01

    Air pollutants have been associated with increased diabetes in humans. We hypothesized that ozone would impair glucose homeostasis by altering insulin signaling and/or endoplasmic reticular (ER) stress in young and aged rats. One, 4, 12, and 24 month old Brown Norway (BN) rats were exposed to air or ozone, 0.25 or 1.0 ppm, 6 h/day for 2 days (acute) or 2 d/week for 13 weeks (subchronic). Additionally, 4 month old rats were exposed to air or 1.0 ppm ozone, 6 h/day for 1 or 2 days (time-course). Glucose tolerance tests (GTT) were performed immediately after exposure. Serum and tissue biomarkers were analyzed 18 h after final ozone for acute and subchronic studies, and immediately after each day of exposure in the time-course study. Age-related glucose intolerance and increases in metabolic biomarkers were apparent at baseline. Acute ozone caused hyperglycemia and glucose intolerance in rats of all ages. Ozone-induced glucose intolerance was reduced in rats exposed for 13 weeks. Acute, but not subchronic ozone increased α 2 -macroglobulin, adiponectin and osteopontin. Time-course analysis indicated glucose intolerance at days 1 and 2 (2 > 1), and a recovery 18 h post ozone. Leptin increased day 1 and epinephrine at all times after ozone. Ozone tended to decrease phosphorylated insulin receptor substrate-1 in liver and adipose tissues. ER stress appeared to be the consequence of ozone induced acute metabolic impairment since transcriptional markers of ER stress increased only after 2 days of ozone. In conclusion, acute ozone exposure induces marked systemic metabolic impairments in BN rats of all ages, likely through sympathetic stimulation. - Highlights: • Air pollutants have been associated with increased diabetes in humans. • Acute ozone exposure produces profound metabolic alterations in rats. • Age influences metabolic risk factors in aging BN rats. • Acute metabolic effects are reversible and repeated exposure reduces these effects. • Ozone metabolic

  13. Ozone induces glucose intolerance and systemic metabolic effects in young and aged brown Norway rats

    Energy Technology Data Exchange (ETDEWEB)

    Bass, V. [Environmental Public Health Division, National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, NC (United States); Gordon, C.J.; Jarema, K.A.; MacPhail, R.C. [Toxicity Assessment Division, National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, NC (United States); Cascio, W.E. [Environmental Public Health Division, National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, NC (United States); Phillips, P.M. [Toxicity Assessment Division, National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, NC (United States); Ledbetter, A.D.; Schladweiler, M.C. [Environmental Public Health Division, National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, NC (United States); Andrews, D. [Research Cores Unit, National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, NC (United States); Miller, D. [Curriculum in Toxicology, University of North Carolina, Chapel Hill, NC (United States); Doerfler, D.L. [Research Cores Unit, National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, NC (United States); Kodavanti, U.P., E-mail: kodavanti.urmila@epa.gov [Environmental Public Health Division, National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, NC (United States)

    2013-12-15

    Air pollutants have been associated with increased diabetes in humans. We hypothesized that ozone would impair glucose homeostasis by altering insulin signaling and/or endoplasmic reticular (ER) stress in young and aged rats. One, 4, 12, and 24 month old Brown Norway (BN) rats were exposed to air or ozone, 0.25 or 1.0 ppm, 6 h/day for 2 days (acute) or 2 d/week for 13 weeks (subchronic). Additionally, 4 month old rats were exposed to air or 1.0 ppm ozone, 6 h/day for 1 or 2 days (time-course). Glucose tolerance tests (GTT) were performed immediately after exposure. Serum and tissue biomarkers were analyzed 18 h after final ozone for acute and subchronic studies, and immediately after each day of exposure in the time-course study. Age-related glucose intolerance and increases in metabolic biomarkers were apparent at baseline. Acute ozone caused hyperglycemia and glucose intolerance in rats of all ages. Ozone-induced glucose intolerance was reduced in rats exposed for 13 weeks. Acute, but not subchronic ozone increased α{sub 2}-macroglobulin, adiponectin and osteopontin. Time-course analysis indicated glucose intolerance at days 1 and 2 (2 > 1), and a recovery 18 h post ozone. Leptin increased day 1 and epinephrine at all times after ozone. Ozone tended to decrease phosphorylated insulin receptor substrate-1 in liver and adipose tissues. ER stress appeared to be the consequence of ozone induced acute metabolic impairment since transcriptional markers of ER stress increased only after 2 days of ozone. In conclusion, acute ozone exposure induces marked systemic metabolic impairments in BN rats of all ages, likely through sympathetic stimulation. - Highlights: • Air pollutants have been associated with increased diabetes in humans. • Acute ozone exposure produces profound metabolic alterations in rats. • Age influences metabolic risk factors in aging BN rats. • Acute metabolic effects are reversible and repeated exposure reduces these effects. • Ozone

  14. The emergence of cold-induced brown adipocytes in mouse white fat depots is determined predominantly by white to brown adipocyte transdifferentiation

    DEFF Research Database (Denmark)

    Barbatelli, G.; Murano, I.; Madsen, Lise

    2010-01-01

    The origin of brown adipocytes arising in white adipose tissue (WAT) after cold acclimatization is unclear. Here, we demonstrate that several UCP1-immunoreactive brown adipocytes occurring in WAT after cold acclimatization have a mixed morphology (paucilocular adipocytes). These cells also had a ...

  15. Fish oil intake induces UCP1 upregulation in brown and white adipose tissue via the sympathetic nervous system.

    Science.gov (United States)

    Kim, Minji; Goto, Tsuyoshi; Yu, Rina; Uchida, Kunitoshi; Tominaga, Makoto; Kano, Yuriko; Takahashi, Nobuyuki; Kawada, Teruo

    2015-12-17

    Brown adipose tissue (BAT) plays a central role in regulating energy homeostasis, and may provide novel strategies for the treatment of human obesity. BAT-mediated thermogenesis is regulated by mitochondrial uncoupling protein 1 (UCP1) in classical brown and ectopic beige adipocytes, and is controlled by sympathetic nervous system (SNS). Previous work indicated that fish oil intake reduces fat accumulation and induces UCP1 expression in BAT; however, the detailed mechanism of this effect remains unclear. In this study, we investigated the effect of fish oil on energy expenditure and the SNS. Fish oil intake increased oxygen consumption and rectal temperature, with concomitant upregulation of UCP1 and the β3 adrenergic receptor (β3AR), two markers of beige adipocytes, in the interscapular BAT and inguinal white adipose tissue (WAT). Additionally, fish oil intake increased the elimination of urinary catecholamines and the noradrenaline (NA) turnover rate in interscapular BAT and inguinal WAT. Furthermore, the effects of fish oil on SNS-mediated energy expenditure were abolished in transient receptor potential vanilloid 1 (TRPV1) knockout mice. In conclusion, fish oil intake can induce UCP1 expression in classical brown and beige adipocytes via the SNS, thereby attenuating fat accumulation and ameliorating lipid metabolism.

  16. Intravenous superoxide dismutase as a protective agent to prevent impairment of lung function induced by high tidal volume ventilation.

    Science.gov (United States)

    Wu, Nan-Chun; Liao, Fan-Ting; Cheng, Hao-Min; Sung, Shih-Hsien; Yang, Yu-Chun; Wang, Jiun-Jr

    2017-07-26

    Positive-pressure mechanical ventilation is essential in assisting patients with respiratory failure in the intensive care unit and facilitating oxygenation in the operating room. However, it was also recognized as a primary factor leading to hospital-acquired pulmonary dysfunction, in which pulmonary oxidative stress and lung inflammation had been known to play important roles. Cu/Zn superoxide dismutase (SOD) is an important antioxidant, and possesses anti-inflammatory capacity. In this study, we aimed to study the efficacy of Cu/Zn SOD, administered intravenously during high tidal volume (HTV) ventilation, to prevent impairment of lung function. Thirty-eight male Sprague-Dawley rats were divided into 3 groups: 5 h ventilation with (A) low tidal volume (LTV; 8 mL/kg; n = 10), (B) high tidal volume (HTV; 18 mL/kg; n = 14), or (C) HTV and intravenous treatment of Cu/Zn SOD at a dose of 1000 U/kg/h (HTV + SOD; n = 14). Lung function was evaluated both at baseline and after 5-h ventilation. Lung injury was assessed by histological examination, lung water and protein contents in the bronchoalveolar lavage fluid (BALF). Pulmonary oxidative stress was examined by concentrations of methylguanidine (MG) and malondialdehyde (MDA) in BALF, and antioxidative activity by protein expression of glutathione peroxidase-1 (GPx-1) in the lung. Severity of lung inflammation was evaluated by white blood cell and differential count in BALF, and protein expression of inducible nitric oxide synthase (iNOS), intercellular adhesion molecule-1 (ICAM-1), tumor necrosis factor-α (TNF-α), matrix metalloproteinase-9 (MMP-9), and mRNA expression of nuclear factor-κB (NF-κB) in the lung. We also examined protein expression of surfactant protein (SP)-A and D and we measured hourly changes in serum nitric oxide (NO) level. Five hours of LTV ventilation did not induce a major change in lung function, whereas 5 h of HTV ventilation induced apparent combined restrictive and

  17. HYPOCHOLESTEROLEMIC AND ANTI-OXIDATIVE PROPERTIES OF GERMINATED BROWN RICE (GBR IN HYPERCHOLESTEROLEMIA-INDUCED RATS

    Directory of Open Access Journals (Sweden)

    Froilan Bernard Matias

    2014-02-01

    Full Text Available Hypercholesterolemia, as one of the causes of obesity, affects vital organs in the body, such as the liver and kidney, resulting to oxidative stress. Germinated Brown Rice (GBR as a food-based solution in dealing with this condition is highly recommended. In this study, the effects of GBR on hypercholesterolemia-induced rats were evaluated by measuring and analyzing the changes on body weight, serum lipid profiles (TC, TG, LDL and HDL, liver function (ALT and AST, kidney function (Crea and Urea and its antioxidant capacity (MDA, SOD, GSH-PX and TAOC. Thirty (30 SD male rats were divided into 5 groups (6 rats per group; Group A was given normal basal diet, Group B (hypercholesterolemic group was given a high fat diet, while Groups C, D, and E were given 12.5%, 25% and 50% GBR, respectively. Groups C, D and E were fed with high fat diet for 4 weeks, then fed with the GBR feeds, accordingly, for another 5 weeks. Sera and liver samples were collected for testing and evaluation. Hypercholesterolemia was successfully induced in Groups B, C, D, and E after 4 weeks. Noticeable responses were observed in groups fed with GBR after 5 weeks. Group E fed with 50% GBR showed the satisfactory results (significant at p<0.05 in weight gain, serum lipid profiles, liver function enzymes, creatinine, urea and oxidative stress markers compared to the hypercholesterolemic group. The hypocholesterolemic and antioxidant properties of GBR were found to have a dose-response effect where higher percentage of GBR showed acceptable results as compared to the normal and hypercholesterolemic groups. GBR showed to effectively lessen TC, TG and LDL while increases HDL. It effectively protects the liver while its kidney protective ability was associated to its hypocholesterolemic properties. Oxidative stress was reduced as shown by a decline in lipid peroxidation and improved antioxidant production. In addition, the abovementioned GBR‘s properties are combined effects of its

  18. Hydrogen peroxide-induced pericarp browning of harvested longan fruit in association with energy metabolism.

    Science.gov (United States)

    Lin, Yifen; Lin, Yixiong; Lin, Hetong; Ritenour, Mark A; Shi, John; Zhang, Shen; Chen, Yihui; Wang, Hui

    2017-06-15

    Energy metabolism of "Fuyan" longan fruit treated with hydrogen peroxide (H 2 O 2 ), the most stable of the reactive oxygen, and its relationship to pericarp browning were investigated in this work. The results displayed that H 2 O 2 significantly decreased contents of adenosine triphosphate (ATP) and adenosine diphosphate (ADP). It also inhibited activities of H + -ATPase, Ca 2+ -ATPase and Mg 2+ -ATPase in membranes of plasma, vacuole and mitochondria during the early-storage and mid-storage (except for mitochondrial membrane Mg 2+ -ATPase). These results gave convincing evidence that the treatment of H 2 O 2 accelerating pericarp browning in harvested longans was due to a decrease of ATPase activity and available ATP content. This might break the ion homeostasis and the integrity of mitochondria, which might reduce energy charge and destroy the function and compartmentalization of cell membrane. These together aggravated browning incidence in pericarp of harvested longan fruit. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Early Overfeed-Induced Obesity Leads to Brown Adipose Tissue Hypoactivity in Rats

    Directory of Open Access Journals (Sweden)

    Douglas L. de Almeida

    2013-12-01

    Full Text Available Background/Aims: Brown adipose tissue activation has been considered a potential anti-obesity mechanism because it is able to expend energy through thermogenesis. In contrast, white adipose tissue stores energy, contributing to obesity. We investigated whether the early programming of obesity by overfeeding during lactation changes structure of interscapular brown adipose tissue in adulthood and its effects on thermogenesis. Methods: Birth of litters was considered day 0. On day 2, litter size was adjusted to normal (9 pups and small (3 pups litters. On day 21, the litters were weaned. A temperature transponder was implanted underneath interscapular brown adipose tissue pads of 81-day-old animals; local temperature was measured during light and dark periods between days 87 and 90. The animals were euthanized, and tissue and blood samples were collected for further analysis. The vagus and retroperitoneal sympathetic nerve activity was recorded. Results: Small litter rats presented significant lower interscapular brown adipose tissue temperature during the light (NL 37.6°C vs. SL 37.2°C and dark (NL 38°C vs. SL 37.6°C periods compared to controls. Morphology of small litter brown adipose tissue showed fewer lipid droplets in the tissue center and more and larger in the periphery. The activity of vagus nerve was 19,9% greater in the small litter than in control (pConclusion: Early overfeeding programming of obesity changes the interscapular brown adipose tissue structure in adulthood, leading to local thermogenesis hypoactivity, which may contribute to obesity in adults.

  20. Early overfeed-induced obesity leads to brown adipose tissue hypoactivity in rats.

    Science.gov (United States)

    de Almeida, Douglas L; Fabrício, Gabriel S; Trombini, Amanda B; Pavanello, Audrei; Tófolo, Laize P; da Silva Ribeiro, Tatiane A; de Freitas Mathias, Paulo C; Palma-Rigo, Kesia

    2013-01-01

    Brown adipose tissue activation has been considered a potential anti-obesity mechanism because it is able to expend energy through thermogenesis. In contrast, white adipose tissue stores energy, contributing to obesity. We investigated whether the early programming of obesity by overfeeding during lactation changes structure of interscapular brown adipose tissue in adulthood and its effects on thermogenesis. Birth of litters was considered day 0. On day 2, litter size was adjusted to normal (9 pups) and small (3 pups) litters. On day 21, the litters were weaned. A temperature transponder was implanted underneath interscapular brown adipose tissue pads of 81-day-old animals; local temperature was measured during light and dark periods between days 87 and 90. The animals were euthanized, and tissue and blood samples were collected for further analysis. The vagus and retroperitoneal sympathetic nerve activity was recorded. Small litter rats presented significant lower interscapular brown adipose tissue temperature during the light (NL 37.6°C vs. SL 37.2°C) and dark (NL 38°C vs. SL 37.6°C) periods compared to controls. Morphology of small litter brown adipose tissue showed fewer lipid droplets in the tissue center and more and larger in the periphery. The activity of vagus nerve was 19,9% greater in the small litter than in control (p<0.01), and no difference was observed in the sympathetic nerve activity. In adulthood, the small litter rats were 11,7% heavier than the controls and presented higher glycemia 13,1%, insulinemia 70% and corticosteronemia 92,6%. Early overfeeding programming of obesity changes the interscapular brown adipose tissue structure in adulthood, leading to local thermogenesis hypoactivity, which may contribute to obesity in adults. © 2013 S. Karger AG, Basel.

  1. Ursolic acid increases skeletal muscle and brown fat and decreases diet-induced obesity, glucose intolerance and fatty liver disease.

    Directory of Open Access Journals (Sweden)

    Steven D Kunkel

    Full Text Available Skeletal muscle Akt activity stimulates muscle growth and imparts resistance to obesity, glucose intolerance and fatty liver disease. We recently found that ursolic acid increases skeletal muscle Akt activity and stimulates muscle growth in non-obese mice. Here, we tested the hypothesis that ursolic acid might increase skeletal muscle Akt activity in a mouse model of diet-induced obesity. We studied mice that consumed a high fat diet lacking or containing ursolic acid. In skeletal muscle, ursolic acid increased Akt activity, as well as downstream mRNAs that promote glucose utilization (hexokinase-II, blood vessel recruitment (Vegfa and autocrine/paracrine IGF-I signaling (Igf1. As a result, ursolic acid increased skeletal muscle mass, fast and slow muscle fiber size, grip strength and exercise capacity. Interestingly, ursolic acid also increased brown fat, a tissue that shares developmental origins with skeletal muscle. Consistent with increased skeletal muscle and brown fat, ursolic acid increased energy expenditure, leading to reduced obesity, improved glucose tolerance and decreased hepatic steatosis. These data support a model in which ursolic acid reduces obesity, glucose intolerance and fatty liver disease by increasing skeletal muscle and brown fat, and suggest ursolic acid as a potential therapeutic approach for obesity and obesity-related illness.

  2. Tides and tidal currents

    NARCIS (Netherlands)

    Roos, A.

    1997-01-01

    Basic phenomena, origin and generation of tides, analysis and prediction of tides, basic equation and types of long waves in one dimension, tidal propagation in one dimension, tidal propagation in two directions, analytical tidal computation, numerical tidal computation.

  3. Tidal Venuses: triggering a climate catastrophe via tidal heating.

    Science.gov (United States)

    Barnes, Rory; Mullins, Kristina; Goldblatt, Colin; Meadows, Victoria S; Kasting, James F; Heller, René

    2013-03-01

    Traditionally, stellar radiation has been the only heat source considered capable of determining global climate on long timescales. Here, we show that terrestrial exoplanets orbiting low-mass stars may be tidally heated at high-enough levels to induce a runaway greenhouse for a long-enough duration for all the hydrogen to escape. Without hydrogen, the planet no longer has water and cannot support life. We call these planets "Tidal Venuses" and the phenomenon a "tidal greenhouse." Tidal effects also circularize the orbit, which decreases tidal heating. Hence, some planets may form with large eccentricity, with its accompanying large tidal heating, and lose their water, but eventually settle into nearly circular orbits (i.e., with negligible tidal heating) in the habitable zone (HZ). However, these planets are not habitable, as past tidal heating desiccated them, and hence should not be ranked highly for detailed follow-up observations aimed at detecting biosignatures. We simulated the evolution of hypothetical planetary systems in a quasi-continuous parameter distribution and found that we could constrain the history of the system by statistical arguments. Planets orbiting stars with massesplanet orbiting a 0.3 MSun star at 0.12 AU. We found that it probably did not lose its water via tidal heating, as orbital stability is unlikely for the high eccentricities required for the tidal greenhouse. As the inner edge of the HZ is defined by the onset of a runaway or moist greenhouse powered by radiation, our results represent a fundamental revision to the HZ for noncircular orbits. In the appendices we review (a) the moist and runaway greenhouses, (b) hydrogen escape, (c) stellar mass-radius and mass-luminosity relations, (d) terrestrial planet mass-radius relations, and (e) linear tidal theories.

  4. Ozone Induces Glucose Intolerance and Systemic Metabolic Effects in Young and Aged Brown Norway Rats

    Science.gov (United States)

    Air pollutants have been associated with increased diabetes in humans. We hypothesized that ozone could impair glucose homeostasis by altering insulin signaling and/or endoplasmic reticular (ER) stress in very young and aged rats. Brown Norway (BN) rats, 1,4, 12, and 24 months ol...

  5. Differential stress-induced regulation of two quinone reductases in the brown rot Basidiomycete Gloeophyllum trabeum

    Science.gov (United States)

    Roni Cohen; Melissa R. Suzuki; Kenneth E. Hammel

    2004-01-01

    Quinone reductases (QRDs) have two important functions in the basidiomycete Gloeophyllum trabeum, which causes brown rot of wood. First, a QRD is required to generate biodegradative hydroxyl radicals via redox cycling between two G. trabeum extracellular metabolites, 2,5-dimethoxyhydroquinone (2,5-DMHQ) and 2,5-dimethoxy-1,4-benzoquinone (2,5- DMBQ). Second, because 2,...

  6. End-tidal concentration of sevoflurane for preventing rocuronium-induced withdrawal of the arm in pediatric patients.

    Science.gov (United States)

    Yeom, Jong Hoon; Kim, Yong Oh; Lee, Jae Min; Jeon, Woo Jae

    2014-04-01

    During induction of general anesthesia, the intravenous injection of rocuronium is often associated with withdrawal movement of the arm due to pain, and this abrupt withdrawal may result in dislodgement of the venous catheter, injury, or inadequate injection of rocuronium. We performed this study to evaluate the 50 and 95% effective end-tidal concentrations of sevoflurane (ETsev) for preventing rocuronium-induced withdrawal of the arm. We conducted a prospective double-blind study in 31 pediatric patients. After free flow of lactated Ringer's IV fluid was confirmed, anesthesia was induced in the patients by using 2.5% thiopental sodium (4 mg/kg) and sevoflurane (4 vol%) with 6 L/min of oxygen. When the target ETsev was reached, preservative-free 1% lidocaine (1.5 mg/kg) was intravenously injected during manual venous occlusion and rocuronium (0.6 mg/kg) was injected after lidocaine injection under free-flow intravenous fluid. A nurse who was an investigator and was blinded to the ETsev injected the rocuronium. The nurse evaluated the response. Non-withdrawal movement was observed in 5 out of 11 patients with ETsev 3.0 vol% and in 5 out of 6 patients with ETsev 3.5 vol%. By Dixon's up-and-down method, the 50% effective concentration (EC50) of sevoflurane for non-withdrawal movement at rocuronium injection was 3.1 ± 0.4 vol%. A logistic regression curve of the probability of non-withdrawal movements showed that the 50% effective ETsev for abolishing withdrawal movement at rocuronium injection was 2.9 vol% (95% confidence interval [CI] 2.4-3.8 vol%) and the 95% effective ETsev was 4.3 vol% (95% CI 3.6-9.8 vol%). This study showed that the 50 and 95% effective ETsev that prevent withdrawal movement at rocuronium injection are 2.9 and 4.3 vol%, respectively.

  7. Methanolic Extracts from Brown Seaweeds Dictyota cilliolata and Dictyota menstrualis Induce Apoptosis in Human Cervical Adenocarcinoma HeLa Cells

    Directory of Open Access Journals (Sweden)

    Dayanne Lopes Gomes

    2015-04-01

    Full Text Available Carcinoma of the uterine cervix is the second most common female tumor worldwide, surpassed only by breast cancer. Natural products from seaweeds evidencing apoptotic activity have attracted a great deal of attention as new leads for alternative and complementary preventive or therapeutic anticancer agents. Here, methanol extracts from 13 species of tropical seaweeds (Rhodophytas, Phaeophyta and Chlorophyta collected from the Northeast of Brazil were assessed as apoptosis-inducing agents on human cervical adenocarcinoma (HeLa. All extracts showed different levels of cytotoxicity against HeLa cells; the most potent were obtained from the brown alga Dictyota cilliolata (MEDC and Dictyota menstrualis (MEDM. In addition, MEDC and MEDM also inhibits SiHa (cervix carcinoma cell proliferation. Studies with these two extracts using flow cytometry and fluorescence microscopy showed that HeLa cells exposed to MEDM and MEDC exhibit morphological and biochemical changes that characterize apoptosis as shown by loss of cell viability, chromatin condensation, phosphatidylserine externalization, and sub-G1 cell cycle phase accumulation, also MEDC induces cell cycle arrest in cell cycle phase S. Moreover, the activation of caspases 3 and 9 by these extracts suggests a mitochondria-dependent apoptosis route. However, other routes cannot be ruled out. Together, these results point out the methanol extracts of the brown algae D. mentrualis and D. cilliolata as potential sources of molecules with antitumor activity.

  8. Neuroprotective Effects of Germinated Brown Rice against Hydrogen Peroxide Induced Cell Death in Human SH-SY5Y Cells

    Directory of Open Access Journals (Sweden)

    Shahid Iqbal

    2012-08-01

    Full Text Available The neuroprotective and antioxidative effects of germinated brown rice (GBR, brown rice (BR and commercially available γ-aminobutyric acid (GABA against cell death induced by hydrogen peroxide (H2O2 in human neuroblastoma SH-SY5Y cells have been investigated. Results show that GBR suppressed H2O2-mediated cytotoxicity and induced G0/G1 phase cell cycle arrest in SH-SY5Y cells. Moreover, GBR reduced mitochondrial membrane potential (MMP and prevented phosphatidylserine (PS translocation in SH-SY5Y cells, key features of apoptosis, and subsequent cell death. GBR exhibited better neuroprotective and antioxidative activities as compared to BR and GABA. These results indicate that GBR possesses high antioxidative activities and suppressed cell death in SH-SY5Y cells by blocking the cell cycle re-entry and apoptotic mechanisms. Therefore, GBR could be developed as a value added functional food to prevent neurodegenerative diseases caused by oxidative stress and apoptosis.

  9. Fluoxetine induces lean phenotype in rat by increasing the brown/white adipose tissue ratio and UCP1 expression.

    Science.gov (United States)

    da Silva, A I; Braz, G R F; Pedroza, A A; Nascimento, L; Freitas, C M; Ferreira, D J S; Manhães de Castro, R; Lagranha, C J

    2015-08-01

    The serotonergic system plays a crucial role in the energy balance regulation. Energy balance is mediated by food intake and caloric expenditure. Thus, the present study investigated the mechanisms that might be associated with fluoxetine treatment-induced weight reduction. Wistar male rat pups received daily injections with subcutaneous fluoxetine (Fx-group) or vehicle solution (Ct-group) from day 1 until 21 days of age. Several analyses were conducted to verify the involvement of mitochondria in weight reduction. We found that body weight in the Fx-group was lower compared to control. In association to lower fat mass in the Fx-group (25%). Neither neonatal caloric intake nor food intake reveals significant differences. Evaluating caloric expenditure (locomotor activity and temperature after stimulus), we did not observe differences in locomotor activity. However, we observed that the Fx group had a higher capacity to maintain body temperature in a cold environment compared with the Ct-group. Since brown adipose tissue-(BAT) is specialized for heat production and the rate of heat production is related to mitochondrial function, we found that Fx-treatment increases respiration by 36%, although after addition of GDP respiration returned to Ct-levels. Examining ROS production we observe that Fx-group produced less ROS than control group. Evaluating uncoupling protein (UCP) expression we found that Fx-treatment increases the expression by 23%. Taken together, our results suggest that modulation of serotonin system results in positive modulation of UCP and mitochondrial bioenergetics in brown fat tissue.

  10. Pivotal Role of O-GlcNAc Modification in Cold-Induced Thermogenesis by Brown Adipose Tissue Through Mitochondrial Biogenesis.

    Science.gov (United States)

    Ohashi, Natsuko; Morino, Katsutaro; Ida, Shogo; Sekine, Osamu; Lemecha, Mengistu; Kume, Shinji; Park, Shi-Young; Choi, Cheol Soo; Ugi, Satoshi; Maegawa, Hiroshi

    2017-09-01

    Adipose tissues considerably influence metabolic homeostasis, and both white (WAT) and brown (BAT) adipose tissue play significant roles in lipid and glucose metabolism. O -linked N -acetylglucosamine ( O -GlcNAc) modification is characterized by the addition of N -acetylglucosamine to various proteins by O -GlcNAc transferase (Ogt), subsequently modulating various cellular processes. However, little is known about the role of O -GlcNAc modification in adipose tissues. Here, we report the critical role of O -GlcNAc modification in cold-induced thermogenesis. Deletion of Ogt in WAT and BAT using adiponectin promoter-driven Cre recombinase resulted in severe cold intolerance with decreased uncoupling protein 1 (Ucp1) expression. Furthermore, Ogt deletion led to decreased mitochondrial protein expression in conjunction with decreased peroxisome proliferator-activated receptor γ coactivator 1-α protein expression. This phenotype was further confirmed by deletion of Ogt in BAT using Ucp1 promoter-driven Cre recombinase, suggesting that O -GlcNAc modification in BAT is responsible for cold-induced thermogenesis. Hypothermia was significant under fasting conditions. This effect was mitigated after normal diet consumption but not after consumption of a fatty acid-rich ketogenic diet lacking carbohydrates, suggesting impaired diet-induced thermogenesis, particularly by fat. In conclusion, O -GlcNAc modification is essential for cold-induced thermogenesis and mitochondrial biogenesis in BAT. Glucose flux into BAT may be a signal to maintain BAT physiological responses. © 2017 by the American Diabetes Association.

  11. Digested BLG can induce tolerance when co-administered with intact BLG in Brown Norway rats

    DEFF Research Database (Denmark)

    Bøgh, Katrine Lindholm; Barkholt, Vibeke; Madsen, Charlotte Bernhard

    the human gastro-duodenal digestion process. Four different fractions of BLG-digest was made, based on sizes of peptides or aggregates hereof. Intact BLG and the four fractions of BLG-digesta were characterized by protein chemical analyses. Brown Norway (BN) rats were immunised i.p. three times without......Background: Milk is a major constituent of small children’s diet. Milk allergy is also one of the most common allergies in small children. Prevention, treatment and general understanding of this allergy are therefore important. Methods: Intact BLG was digested in an in vitro model simulating...... the use of adjuvant with either PBS (control), 200 µg of intact BLG, 30 µg of intact BLG, 200 µg of digested BLG (with 30 µg of intact BLG), 200 µg of digested BLG, 200 µg of a fraction of large complexes or 200 µg of a fraction of small complexes (all three without intact BLG). Sera from BN rats were...

  12. Brown-Séquard syndrome following intracranial subarachnoid hemorrhage-induced spinal arachnoid cyst

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    Yew-Weng Fong

    2017-12-01

    Full Text Available Objective: Arachnoid cyst associated with spinal arachnoiditis following subarachnoid hemorrhage (SAH is a rare complication. Correctly diagnosing this condition and providing an effective treatment are extremely important. Case report: A 60-year-old women had a history of SAH due to an intradural vertebral artery dissecting aneurysm post-coil embolization, without neurologic deficits on discharge from our institution. She experienced left hemiparesis with muscle power graded at 4/5 eight months later due to a right middle cerebral artery territory infarct. Nine months after stroke rehabilitation, there was a progression of left-side weakness and right-side numbness down below the nipple level. On neurological examination, there were right sensory deficits below T6, and left hemiparesis with muscle power of the left upper extremity graded at 4/5 and that of the left lower extremity graded at 3/5. Deep tendon reflex was symmetrically increased at the bilateral lower extremities. Spinal magnetic resonance imaging (MRI revealed a cervicothoracic multiseptated arachnoid cyst with a major compression effect at T6. Eight months after T5–6 hemilaminectomy and fenestration of the cyst wall, the neurologic deficits had not improved. The patient then underwent a cysto-peritoneal shunt. A follow-up MRI documented a complete resolution of the arachnoid cyst. The patient's Brown-Séquard syndrome showed clinical improvement. Conclusion: Prompt investigation revealed a spinal arachnoid cyst in a patient with a history of intracranial SAH presenting with unexplained progressive Brown-Séquard syndrome. For cases of multiseptated and long arachnoid cyst, as in our patient, a shunting procedure is a better choice than fenestration alone.

  13. Modelling tidal current-induced bed shear stress and palaeocirculation in an epicontinental seaway: the Bohemian Cretaceous Basin, Central Europe

    Czech Academy of Sciences Publication Activity Database

    Mitchell, A. J.; Uličný, David; Hampson, G. J.; Allison, P. A.; Gorman, G. J.; Piggott, M. D.; Wells, M. R.; Pain, C. C.

    2010-01-01

    Roč. 57, č. 2 (2010), s. 359-388 ISSN 0037-0746 R&D Projects: GA AV ČR(CZ) IAA300120609 Institutional research plan: CEZ:AV0Z30120515 Keywords : bed shear stress * Bohemian Cretaceous Basin * epicontinental sea * tidal circulation * Turonian Subject RIV: DB - Geology ; Mineralogy Impact factor: 2.229, year: 2010

  14. Tidal-induced large-scale regular bed form patterns in a three-dimensional shallow water model

    NARCIS (Netherlands)

    Hulscher, Suzanne J.M.H.

    1996-01-01

    The three-dimensional model presented in this paper is used to study how tidal currents form wave-like bottom patterns. Inclusion of vertical flow structure turns out to be necessary to describe the formation, or absence, of all known large-scale regular bottom features. The tide and topography are

  15. Non-transactivational, dual pathways for LPA-induced Erk1/2 activation in primary cultures of brown pre-adipocytes

    International Nuclear Information System (INIS)

    Holmstroem, Therese E.; Mattsson, Charlotte L.; Wang, Yanling; Iakovleva, Irina; Petrovic, Natasa; Nedergaard, Jan

    2010-01-01

    In many cell types, G-protein-coupled receptor (GPCR)-induced Erk1/2 MAP kinase activation is mediated via receptor tyrosine kinase (RTK) transactivation, in particular via the epidermal growth factor (EGF) receptor. Lysophosphatidic acid (LPA), acting via GPCRs, is a mitogen and MAP kinase activator in many systems, and LPA can regulate adipocyte proliferation. The mechanism by which LPA activates the Erk1/2 MAP kinase is generally accepted to be via EGF receptor transactivation. In primary cultures of brown pre-adipocytes, EGF can induce Erk1/2 activation, which is obligatory and determinant for EGF-induced proliferation of these cells. Therefore, we have here examined whether LPA, via EGF transactivation, can activate Erk1/2 in brown pre-adipocytes. We found that LPA could induce Erk1/2 activation. However, the LPA-induced Erk1/2 activation was independent of transactivation of EGF receptors (or PDGF receptors) in these cells (whereas in transformed HIB-1B brown adipocytes, the LPA-induced Erk1/2 activation indeed proceeded via EGF receptor transactivation). In the brown pre-adipocytes, LPA instead induced Erk1/2 activation via two distinct non-transactivational pathways, one G i -protein dependent, involving PKC and Src activation, the other, a PTX-insensitive pathway, involving PI3K (but not Akt) activation. Earlier studies showing LPA-induced Erk1/2 activation being fully dependent on RTK transactivation have all been performed in cell lines and transfected cells. The present study implies that in non-transformed systems, RTK transactivation may not be involved in the mediation of GPCR-induced Erk1/2 MAP kinase activation.

  16. Reprogrammed Functional Brown Adipocytes Ameliorate Insulin Resistance and Dyslipidemia in Diet-Induced Obesity and Type 2 Diabetes

    Directory of Open Access Journals (Sweden)

    Tsunao Kishida

    2015-10-01

    Full Text Available Brown adipocytes (BAs play important roles in body temperature regulation, energy balance, and carbohydrate and lipid metabolism. Activities of BAs are remarkably diminished in obese and diabetic patients, providing possibilities of transplanting functional BAs resulting in therapeutic benefit. Here, we show generation of functional BAs by cellular reprogramming procedures. Transduction of the PRDM16 gene into iPSC-derived embryoid bodies induced BA phenotypes (iBAs. Moreover, normal human fibroblasts were directly converted into BAs (dBAs by C/EBP-β and C-MYC gene transduction. Approximately 90% of the fibroblasts were successfully converted within 12 days. The dBAs were highly active in mitochondrial biogenesis and oxidative metabolism. Mouse dBAs were induced by Prdm16, C/ebp-β, and L-myc genes, and after transplantation, they significantly reduced diet-induced obesity and insulin resistance in an UCP1-dependent manner. Thus, highly functional BAs can be generated by cellular reprogramming, suggesting a promising tailor-made cell therapy against metabolic disorders including type 2 diabetes mellitus.

  17. Reprogrammed Functional Brown Adipocytes Ameliorate Insulin Resistance and Dyslipidemia in Diet-Induced Obesity and Type 2 Diabetes.

    Science.gov (United States)

    Kishida, Tsunao; Ejima, Akika; Yamamoto, Kenta; Tanaka, Seiji; Yamamoto, Toshiro; Mazda, Osam

    2015-10-13

    Brown adipocytes (BAs) play important roles in body temperature regulation, energy balance, and carbohydrate and lipid metabolism. Activities of BAs are remarkably diminished in obese and diabetic patients, providing possibilities of transplanting functional BAs resulting in therapeutic benefit. Here, we show generation of functional BAs by cellular reprogramming procedures. Transduction of the PRDM16 gene into iPSC-derived embryoid bodies induced BA phenotypes (iBAs). Moreover, normal human fibroblasts were directly converted into BAs (dBAs) by C/EBP-β and C-MYC gene transduction. Approximately 90% of the fibroblasts were successfully converted within 12 days. The dBAs were highly active in mitochondrial biogenesis and oxidative metabolism. Mouse dBAs were induced by Prdm16, C/ebp-β, and L-myc genes, and after transplantation, they significantly reduced diet-induced obesity and insulin resistance in an UCP1-dependent manner. Thus, highly functional BAs can be generated by cellular reprogramming, suggesting a promising tailor-made cell therapy against metabolic disorders including type 2 diabetes mellitus. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

  18. LC-MS Untargeted Metabolomics To Explain the Signal Metabolites Inducing Browning in Fresh-Cut Lettuce.

    Science.gov (United States)

    García, Carlos J; García-Villalba, Rocío; Gil, María I; Tomas-Barberan, Francisco A

    2017-06-07

    Enzymatic browning is one of the main causes of quality loss in lettuce as a prepared and ready-to-eat cut salad. An untargeted metabolomics approach using UPLC-ESI-QTOF-MS was performed to explain the wound response of lettuce after cutting and to identify the metabolites responsible of browning. Two cultivars of Romaine lettuce with different browning susceptibilities were studied at short time intervals after cutting. From the total 5975 entities obtained from the raw data after alignment, filtration reduced the number of features to 2959, and the statistical analysis found that only 1132 entities were significantly different. Principal component analysis (PCA) clearly showed that these samples grouped according to cultivar and time after cutting. From those, only 15 metabolites belonging to lysophospholipids, oxylipin/jasmonate metabolites, and phenolic compounds were able to explain the browning process. These selected metabolites showed different trends after cutting; some decreased rapidly, others increased but decreased thereafter, whereas others increased during the whole period of storage. In general, the fast-browning cultivar showed a faster wound response and a higher raw intensity of some key metabolites than the slow-browning one. Just after cutting, the fast-browning cultivar contained 11 of the 15 browning-associated metabolites, whereas the slow-browning cultivar only had 5 of them. These metabolites could be used as biomarkers in breeding programs for the selection of lettuce cultivars with lower browning potential for fresh-cut applications.

  19. Tidal Venuses: Triggering a Climate Catastrophe via Tidal Heating

    Science.gov (United States)

    Mullins, Kristina; Goldblatt, Colin; Meadows, Victoria S.; Kasting, James F.; Heller, René

    2013-01-01

    Abstract Traditionally, stellar radiation has been the only heat source considered capable of determining global climate on long timescales. Here, we show that terrestrial exoplanets orbiting low-mass stars may be tidally heated at high-enough levels to induce a runaway greenhouse for a long-enough duration for all the hydrogen to escape. Without hydrogen, the planet no longer has water and cannot support life. We call these planets “Tidal Venuses” and the phenomenon a “tidal greenhouse.” Tidal effects also circularize the orbit, which decreases tidal heating. Hence, some planets may form with large eccentricity, with its accompanying large tidal heating, and lose their water, but eventually settle into nearly circular orbits (i.e., with negligible tidal heating) in the habitable zone (HZ). However, these planets are not habitable, as past tidal heating desiccated them, and hence should not be ranked highly for detailed follow-up observations aimed at detecting biosignatures. We simulated the evolution of hypothetical planetary systems in a quasi-continuous parameter distribution and found that we could constrain the history of the system by statistical arguments. Planets orbiting stars with massestidal heating. We have applied these concepts to Gl 667C c, a ∼4.5 MEarth planet orbiting a 0.3 MSun star at 0.12 AU. We found that it probably did not lose its water via tidal heating, as orbital stability is unlikely for the high eccentricities required for the tidal greenhouse. As the inner edge of the HZ is defined by the onset of a runaway or moist greenhouse powered by radiation, our results represent a fundamental revision to the HZ for noncircular orbits. In the appendices we review (a) the moist and runaway greenhouses, (b) hydrogen escape, (c) stellar mass-radius and mass-luminosity relations, (d) terrestrial planet mass-radius relations, and (e) linear tidal theories. Key Words: Extrasolar terrestrial planets—Habitability—Habitable zone

  20. Tidal locking of habitable exoplanets

    Science.gov (United States)

    Barnes, Rory

    2017-12-01

    Potentially habitable planets can orbit close enough to their host star that the differential gravity across their diameters can produce an elongated shape. Frictional forces inside the planet prevent the bulges from aligning perfectly with the host star and result in torques that alter the planet's rotational angular momentum. Eventually the tidal torques fix the rotation rate at a specific frequency, a process called tidal locking. Tidally locked planets on circular orbits will rotate synchronously, but those on eccentric orbits will either librate or rotate super-synchronously. Although these features of tidal theory are well known, a systematic survey of the rotational evolution of potentially habitable exoplanets using classic equilibrium tide theories has not been undertaken. I calculate how habitable planets evolve under two commonly used models and find, for example, that one model predicts that the Earth's rotation rate would have synchronized after 4.5 Gyr if its initial rotation period was 3 days, it had no satellites, and it always maintained the modern Earth's tidal properties. Lower mass stellar hosts will induce stronger tidal effects on potentially habitable planets, and tidal locking is possible for most planets in the habitable zones of GKM dwarf stars. For fast-rotating planets, both models predict eccentricity growth and that circularization can only occur once the rotational frequency is similar to the orbital frequency. The orbits of potentially habitable planets of very late M dwarfs ([InlineEquation not available: see fulltext.]) are very likely to be circularized within 1 Gyr, and hence, those planets will be synchronous rotators. Proxima b is almost assuredly tidally locked, but its orbit may not have circularized yet, so the planet could be rotating super-synchronously today. The evolution of the isolated and potentially habitable Kepler planet candidates is computed and about half could be tidally locked. Finally, projected TESS planets

  1. Inhibition of Intracellular Triglyceride Lipolysis Suppresses Cold-Induced Brown Adipose Tissue Metabolism and Increases Shivering in Humans.

    Science.gov (United States)

    Blondin, Denis P; Frisch, Frédérique; Phoenix, Serge; Guérin, Brigitte; Turcotte, Éric E; Haman, François; Richard, Denis; Carpentier, André C

    2017-02-07

    Indirect evidence from human studies suggests that brown adipose tissue (BAT) thermogenesis is fueled predominantly by fatty acids hydrolyzed from intracellular triglycerides (TGs). However, no direct experimental evidence to support this assumption currently exists in humans. The aim of this study was to determine the role of intracellular TG in BAT thermogenesis, in cold-exposed men. Using positron emission tomography with 11 C-acetate and 18 F-fluorodeoxyglucose, we showed that oral nicotinic acid (NiAc) administration, an inhibitor of intracellular TG lipolysis, suppressed the cold-induced increase in BAT oxidative metabolism and glucose uptake, despite no difference in BAT blood flow. There was a commensurate increase in shivering intensity and shift toward a greater reliance on glycolytic muscle fibers without modifying total heat production. Together, these findings show that intracellular TG lipolysis is critical for BAT thermogenesis and provides experimental evidence for a reciprocal role of BAT thermogenesis and shivering in cold-induced thermogenesis in humans. Copyright © 2017 Elsevier Inc. All rights reserved.

  2. Impact of Different Tidal Volume Levels at Low Mechanical Power on Ventilator-Induced Lung Injury in Rats

    Directory of Open Access Journals (Sweden)

    Lillian Moraes

    2018-04-01

    Full Text Available Tidal volume (VT has been considered the main determinant of ventilator-induced lung injury (VILI. Recently, experimental studies have suggested that mechanical power transferred from the ventilator to the lungs is the promoter of VILI. We hypothesized that, as long as mechanical power is kept below a safe threshold, high VT should not be injurious. The present study aimed to investigate the impact of different VT levels and respiratory rates (RR on lung function, diffuse alveolar damage (DAD, alveolar ultrastructure, and expression of genes related to inflammation [interleukin (IL-6], alveolar stretch (amphiregulin, epithelial [club cell secretory protein (CC16] and endothelial [intercellular adhesion molecule (ICAM-1] cell injury, and extracellular matrix damage [syndecan-1, decorin, and metalloproteinase (MMP-9] in experimental acute respiratory distress syndrome (ARDS under low-power mechanical ventilation. Twenty-eight Wistar rats received Escherichia coli lipopolysaccharide intratracheally. After 24 h, 21 animals were randomly assigned to ventilation (2 h with low mechanical power at three different VT levels (n = 7/group: (1 VT = 6 mL/kg and RR adjusted to normocapnia; (2 VT = 13 mL/kg; and 3 VT = 22 mL/kg. In the second and third groups, RR was adjusted to yield low mechanical power comparable to that of the first group. Mechanical power was calculated as [(ΔP,L2/Est,L/2]× RR (ΔP,L = transpulmonary driving pressure, Est,L = static lung elastance. Seven rats were not mechanically ventilated (NV and were used for molecular biology analysis. Mechanical power was comparable among groups, while VT gradually increased. ΔP,L and mechanical energy were higher in VT = 22 mL/kg than VT = 6 mL/kg and VT = 13 mL/kg (p < 0.001 for both. Accordingly, DAD score increased in VT = 22 mL/kg compared to VT = 6 mL/kg and VT = 13 mL/kg [23(18.5–24.75 vs. 16(12–17.75 and 16(13.25–18, p < 0.05, respectively]. VT = 22 mL/kg was associated with higher

  3. Anti-obesity effects of Arctii Fructus (Arctium lappa) in white/brown adipocytes and high-fat diet-induced obese mice.

    Science.gov (United States)

    Han, Yo-Han; Kee, Ji-Ye; Kim, Dae-Seung; Park, Jinbong; Jeong, Mi-Young; Mun, Jung-Geon; Park, Sung-Joo; Lee, Jong-Hyun; Um, Jae-Young; Hong, Seung-Heon

    2016-12-07

    Arctii Fructus is traditionally used in oriental pharmacies as an anti-inflammatory medicine. Although several studies have shown its anti-inflammatory effects, there have been no reports on its use in obesity related studies. In this study, the anti-obesity effect of Arctii Fructus was investigated in high-fat diet (HFD)-induced obese mice, and the effect was confirmed in white and primary cultured brown adipocytes. Arctii Fructus inhibited weight gain and reduced the mass of white adipose tissue in HFD-induced obese mice. Serum levels of triglyceride and LDL-cholesterol were reduced, and HDL-cholesterol was increased in the Arctii Fructus treated group. In 3T3-L1 cells, a water extract (WAF) and 70% EtOH extract (EtAF) of Arctii Fructus significantly inhibited adipogenesis and suppressed the expression of proliferator-activated receptor gamma and CCAAT/enhancer-binding protein alpha. In particular, EtAF activated the phosphorylation of AMP-activated protein kinase. On the other hand, uncoupling protein 1 and peroxisome proliferator-activated receptor gamma coactivator 1-alpha, known as brown adipocytes specific genes, were increased in primary cultured brown adipocytes by WAF and EtAF. This study shows that Arctii Fructus prevents the development of obesity through the inhibition of white adipocyte differentiation and activation of brown adipocyte differentiation which suggests that Arctii Fructus could be an effective therapeutic for treating or preventing obesity.

  4. Stress-induced activation of brown adipose tissue prevents obesity in conditions of low adaptive thermogenesis

    Directory of Open Access Journals (Sweden)

    Maria Razzoli

    2016-01-01

    Conclusion: Our findings demonstrate that thermogenesis and BAT function are determinant of the resilience or vulnerability to stress-induced obesity. Our data support a model in which adrenergic and purinergic pathways exert complementary/synergistic functions in BAT, thus suggesting an alternative to βARs agonists for the activation of human BAT.

  5. Flocculation and floc break-up related to tidally induced turbulent shear in a low-turbidity, microtidal estuary

    DEFF Research Database (Denmark)

    Markussen, Thor Nygaard; Andersen, Thorbjørn Joest

    2014-01-01

    flocculation and floc break-up dynamics in the lower part of the water column in the period around slack water. These dynamics were confirmed in the Eulerian deployments and were reoccurring in every tidal cycle. The dynamics were mostly governed by changes in turbulent shear. Strong microflocs with a lower...... mean threshold diameter of 50–60 μm present at high turbulent shear flocculated to form fragile macroflocs with sizes of several hundred microns and mean diameters above 80 μm around slack water periods. A hysteresis in floc break-up and flocculation was found at high water slack (HWS), as flocs formed...

  6. The role of the brown adipose tissue in β3-adrenergic receptor activation-induced sleep, metabolic and feeding responses.

    Science.gov (United States)

    Szentirmai, Éva; Kapás, Levente

    2017-04-19

    Brown adipose tissue (BAT) is regulated by the sympathetic nervous system via β3-adrenergic receptors (β3-AR). Here we tested the hypothesis that pharmacological stimulation of β3-ARs leads to increased sleep in mice and if this change is BAT dependent. In wild-type (WT) animals, administration of CL-316,243, a selective β3-AR agonist, induced significant increases in non-rapid-eye movement sleep (NREMS) lasting for 4-10 h. Simultaneously, electroencephalographic slow-wave activity (SWA) was significantly decreased and body temperature was increased with a delay of 5-6 h. In uncoupling protein 1 (UCP-1) knockout mice, the middle and highest doses of the β3-AR agonist increased sleep and suppressed SWA, however, these effects were significantly attenuated and shorter-lasting as compared to WT animals. To determine if somnogenic signals arising from BAT in response to β3-AR stimulation are mediated by the sensory afferents of BAT, we tested the effects of CL-316,243 in mice with the chemical deafferentation of the intra-scapular BAT pads. Sleep responses to CL-316,243 were attenuated by ~50% in intra-BAT capsaicin-treated mice. Present findings indicate that the activation of BAT via β3-AR leads to increased sleep in mice and that this effect is dependent on the presence of UCP-1 protein and sleep responses require the intact sensory innervation of BAT.

  7. The Suppressive Activity of Fucofuroeckol-A Derived from Brown Algal Ecklonia stolonifera Okamura on UVB-Induced Mast Cell Degranulation

    Directory of Open Access Journals (Sweden)

    Thanh Sang Vo

    2018-01-01

    Full Text Available UV light, especially UVB, is known as a trigger of allergic reaction, leading to mast cell degranulation and histamine release. In this study, phlorotannin Fucofuroeckol-A (F-A derived from brown algal Ecklonia stolonifera Okamura was evaluated for its protective capability against UVB-induced allergic reaction in RBL-2H3 mast cells. It was revealed that F-A significantly suppress mast cell degranulation via decreasing histamine release as well as intracellular Ca2+ elevation at the concentration of 50 μM. Moreover, the inhibitory effect of F-A on IL-1β and TNF-α productions was also evidenced. Notably, the protective activity of F-A against mast cell degranulation was found due to scavenging ROS production. Accordingly, F-A from brown algal E. stolonifera was suggested to be promising candidate for its protective capability against UVB-induced allergic reaction.

  8. Mechanical ventilation with high tidal volumes attenuates myocardial dysfunction by decreasing cardiac edema in a rat model of LPS-induced peritonitis

    Directory of Open Access Journals (Sweden)

    Smeding Lonneke

    2012-03-01

    Full Text Available Abstract Background Injurious mechanical ventilation (MV may augment organ injury remote from the lungs. During sepsis, myocardial dysfunction is common and increased endothelial activation and permeability can cause myocardial edema, which may, among other factors, hamper myocardial function. We investigated the effects of MV with injuriously high tidal volumes on the myocardium in an animal model of sepsis. Methods Normal rats and intraperitoneal (i.p. lipopolysaccharide (LPS-treated rats were ventilated with low (6 ml/kg and high (19 ml/kg tidal volumes (Vt under general anesthesia. Non-ventilated animals served as controls. Mean arterial pressure (MAP, central venous pressure (CVP, cardiac output (CO and pulmonary plateau pressure (Pplat were measured. Ex vivo myocardial function was measured in isolated Langendorff-perfused hearts. Cardiac expression of endothelial vascular cell adhesion molecule (VCAM-1 and edema were measured to evaluate endothelial inflammation and leakage. Results MAP decreased after LPS-treatment and Vt-dependently, both independent of each other and with interaction. MV Vt-dependently increased CVP and Pplat and decreased CO. LPS-induced peritonitis decreased myocardial function ex vivo but MV attenuated systolic dysfunction Vt-dependently. Cardiac endothelial VCAM-1 expression was increased by LPS treatment independent of MV. Cardiac edema was lowered Vt-dependently by MV, particularly after LPS, and correlated inversely with systolic myocardial function parameters ex vivo. Conclusion MV attenuated LPS-induced systolic myocardial dysfunction in a Vt-dependent manner. This was associated with a reduction in cardiac edema following a lower transmural coronary venous outflow pressure during LPS-induced coronary inflammation.

  9. Dissipation of Tidal Energy

    Science.gov (United States)

    2002-01-01

    accounting for tidally induced ocean mixing may have important implications for long-term climate modeling', Egbert said. In the past, most geophysical theories held that the only significant tidal energy sink was bottom friction in shallow seas. Egbert and Ray find that this sink is indeed dominant, but it is not the whole story. There had always been suggestive evidence that tidal energy is also dissipated in the open ocean to create internal waves, but published estimates of this effect varied widely and had met with no general consensus before TOPEX/Poseidon. TOPEX/Poseidon mission, a joint U.S.-French mission, is managed by the Jet Propulsion Laboratory for NASA's Office of Earth Science, Washington, DC. The satellite was launched in August 1992, and it continues to produce sea level measurements of the highest quality. For supporting images: http://svs.gsfc.nasa.gov/search/Instrumentsdatasets/TOPEX-POSEIDON.html Image by Richard Ray, NASA GSFC

  10. Identification of candidate genes and molecular markers for heat-induced brown discoloration of seed coats in cowpea [Vigna unguiculata (L.) Walp].

    Science.gov (United States)

    Pottorff, Marti; Roberts, Philip A; Close, Timothy J; Lonardi, Stefano; Wanamaker, Steve; Ehlers, Jeffrey D

    2014-05-01

    Heat-induced browning (Hbs) of seed coats is caused by high temperatures which discolors the seed coats of many legumes, affecting the visual appearance and quality of seeds. The genetic determinants underlying Hbs in cowpea are unknown. We identified three QTL associated with the heat-induced browning of seed coats trait, Hbs-1, Hbs-2 and Hbs-3, using cowpea RIL populations IT93K-503-1 (Hbs positive) x CB46 (hbs negative) and IT84S-2246 (Hbs positive) x TVu14676 (hbs negative). Hbs-1 was identified in both populations, accounting for 28.3% -77.3% of the phenotypic variation. SNP markers 1_0032 and 1_1128 co-segregated with the trait. Within the syntenic regions of Hbs-1 in soybean, Medicago and common bean, several ethylene forming enzymes, ethylene responsive element binding factors and an ACC oxidase 2 were observed. Hbs-1 was identified in a BAC clone in contig 217 of the cowpea physical map, where ethylene forming enzymes were present. Hbs-2 was identified in the IT93K-503-1 x CB46 population and accounted for of 9.5 to 12.3% of the phenotypic variance. Hbs-3 was identified in the IT84S-2246 x TVu14676 population and accounted for 6.2 to 6.8% of the phenotypic variance. SNP marker 1_0640 co-segregated with the heat-induced browning phenotype. Hbs-3 was positioned on BAC clones in contig512 of the cowpea physical map, where several ACC synthase 1 genes were present. The identification of loci determining heat-induced browning of seed coats and co-segregating molecular markers will enable transfer of hbs alleles into cowpea varieties, contributing to higher quality seeds.

  11. In uncontrolled diabetes, thyroid hormone and sympathetic activators induce thermogenesis without increasing glucose uptake in brown adipose tissue.

    Science.gov (United States)

    Matsen, Miles E; Thaler, Joshua P; Wisse, Brent E; Guyenet, Stephan J; Meek, Thomas H; Ogimoto, Kayoko; Cubelo, Alex; Fischer, Jonathan D; Kaiyala, Karl J; Schwartz, Michael W; Morton, Gregory J

    2013-04-01

    Recent advances in human brown adipose tissue (BAT) imaging technology have renewed interest in the identification of BAT activators for the treatment of obesity and diabetes. In uncontrolled diabetes (uDM), activation of BAT is implicated in glucose lowering mediated by intracerebroventricular (icv) administration of leptin, which normalizes blood glucose levels in streptozotocin (STZ)-induced diabetic rats. The potent effect of icv leptin to increase BAT glucose uptake in STZ-diabetes is accompanied by the return of reduced plasma thyroxine (T4) levels and BAT uncoupling protein-1 (Ucp1) mRNA levels to nondiabetic controls. We therefore sought to determine whether activation of thyroid hormone receptors is sufficient in and of itself to lower blood glucose levels in STZ-diabetes and whether this effect involves activation of BAT. We found that, although systemic administration of the thyroid hormone (TR)β-selective agonist GC-1 increases energy expenditure and induces further weight loss in STZ-diabetic rats, it neither increased BAT glucose uptake nor attenuated diabetic hyperglycemia. Even when GC-1 was administered in combination with a β(3)-adrenergic receptor agonist to mimic sympathetic nervous system activation, glucose uptake was not increased in STZ-diabetic rats, nor was blood glucose lowered, yet this intervention potently activated BAT. Similar results were observed in animals treated with active thyroid hormone (T3) instead of GC-1. Taken together, our data suggest that neither returning normal plasma thyroid hormone levels nor BAT activation has any impact on diabetic hyperglycemia, and that in BAT, increases of Ucp1 gene expression and glucose uptake are readily dissociated from one another in this setting.

  12. Refeeding-induced brown adipose tissue glycogen hyper-accumulation in mice is mediated by insulin and catecholamines.

    Directory of Open Access Journals (Sweden)

    Christopher M Carmean

    Full Text Available Brown adipose tissue (BAT generates heat during adaptive thermogenesis through a combination of oxidative metabolism and uncoupling protein 1-mediated electron transport chain uncoupling, using both free-fatty acids and glucose as substrate. Previous rat-based work in 1942 showed that prolonged partial fasting followed by refeeding led to a dramatic, transient increase in glycogen stores in multiple fat depots. In the present study, the protocol was replicated in male CD1 mice, resulting in a 2000-fold increase in interscapular BAT (IBAT glycogen levels within 4-12 hours (hr of refeeding, with IBAT glycogen stores reaching levels comparable to fed liver glycogen. Lesser effects occurred in white adipose tissues (WAT. Over the next 36 hr, glycogen levels dissipated and histological analysis revealed an over-accumulation of lipid droplets, suggesting a potential metabolic connection between glycogenolysis and lipid synthesis. 24 hr of total starvation followed by refeeding induced a robust and consistent glycogen over-accumulation similar in magnitude and time course to the prolonged partial fast. Experimentation demonstrated that hyperglycemia was not sufficient to drive glycogen accumulation in IBAT, but that elevated circulating insulin was sufficient. Additionally, pharmacological inhibition of catecholamine production reduced refeeding-induced IBAT glycogen storage, providing evidence of a contribution from the central nervous system. These findings highlight IBAT as a tissue that integrates both canonically-anabolic and catabolic stimulation for the promotion of glycogen storage during recovery from caloric deficit. The preservation of this robust response through many generations of animals not subjected to food deprivation suggests that the over-accumulation phenomenon plays a critical role in IBAT physiology.

  13. Refeeding-Induced Brown Adipose Tissue Glycogen Hyper-Accumulation in Mice Is Mediated by Insulin and Catecholamines

    Science.gov (United States)

    Carmean, Christopher M.; Bobe, Alexandria M.; Yu, Justin C.; Volden, Paul A.; Brady, Matthew J.

    2013-01-01

    Brown adipose tissue (BAT) generates heat during adaptive thermogenesis through a combination of oxidative metabolism and uncoupling protein 1-mediated electron transport chain uncoupling, using both free-fatty acids and glucose as substrate. Previous rat-based work in 1942 showed that prolonged partial fasting followed by refeeding led to a dramatic, transient increase in glycogen stores in multiple fat depots. In the present study, the protocol was replicated in male CD1 mice, resulting in a 2000-fold increase in interscapular BAT (IBAT) glycogen levels within 4–12 hours (hr) of refeeding, with IBAT glycogen stores reaching levels comparable to fed liver glycogen. Lesser effects occurred in white adipose tissues (WAT). Over the next 36 hr, glycogen levels dissipated and histological analysis revealed an over-accumulation of lipid droplets, suggesting a potential metabolic connection between glycogenolysis and lipid synthesis. 24 hr of total starvation followed by refeeding induced a robust and consistent glycogen over-accumulation similar in magnitude and time course to the prolonged partial fast. Experimentation demonstrated that hyperglycemia was not sufficient to drive glycogen accumulation in IBAT, but that elevated circulating insulin was sufficient. Additionally, pharmacological inhibition of catecholamine production reduced refeeding-induced IBAT glycogen storage, providing evidence of a contribution from the central nervous system. These findings highlight IBAT as a tissue that integrates both canonically-anabolic and catabolic stimulation for the promotion of glycogen storage during recovery from caloric deficit. The preservation of this robust response through many generations of animals not subjected to food deprivation suggests that the over-accumulation phenomenon plays a critical role in IBAT physiology. PMID:23861810

  14. The influence of waves on the tidal kinetic energy resource at a tidal stream energy site

    International Nuclear Information System (INIS)

    Guillou, Nicolas; Chapalain, Georges; Neill, Simon P.

    2016-01-01

    Highlights: • We model the influence of waves on tidal kinetic energy in the Fromveur Strait. • Numerical results are compared with field data of waves and currents. • The introduction of waves improve predictions of tidal stream power during storm. • Mean spring tidal stream potential is reduced by 12% during extreme wave conditions. • Potential is reduced by 7.8% with waves forces and 5.3% with enhanced friction. - Abstract: Successful deployment of tidal energy converters relies on access to accurate and high resolution numerical assessments of available tidal stream power. However, since suitable tidal stream sites are located in relatively shallow waters of the continental shelf where tidal currents are enhanced, tidal energy converters may experience effects of wind-generated surface-gravity waves. Waves may thus influence tidal currents, and associated kinetic energy, through two non-linear processes: the interaction of wave and current bottom boundary layers, and the generation of wave-induced currents. Here, we develop a three-dimensional tidal circulation model coupled with a phase-averaged wave model to quantify the impact of the waves on the tidal kinetic energy resource of the Fromveur Strait (western Brittany) - a region that has been identified with strong potential for tidal array development. Numerical results are compared with in situ observations of wave parameters (significant wave height, peak period and mean wave direction) and current amplitude and direction 10 m above the seabed (the assumed technology hub height for this region). The introduction of waves is found to improve predictions of tidal stream power at 10 m above the seabed at the measurement site in the Strait, reducing kinetic energy by up to 9% during storm conditions. Synoptic effects of wave radiation stresses and enhanced bottom friction are more specifically identified at the scale of the Strait. Waves contribute to a slight increase in the spatial gradient of

  15. Effects of the nonsugar fraction of brown sugar on chronic ultraviolet B irradiation-induced photoaging in melanin-possessing hairless mice.

    Science.gov (United States)

    Sumiyoshi, Maho; Hayashi, Teruaki; Kimura, Yoshiyuki

    2009-04-01

    Brown sugar has been used traditionally for the treatment of skin trouble as a component of soaps or lotions. Symptoms of aging including wrinkles and pigmentation develop earlier in sun-exposed skin than unexposed skin, a phenomenon referred to as photoaging. Ultraviolet B (UVB) radiation is one of the most important environmental factors influencing photoaging. The aim of this study was to clarify whether the nonsugar fraction of brown sugar prevents chronic UVB-induced aging of the skin using melanin-possessing hairless mice. The nonsugar fraction (1% or 3% solution, 50 mul/mouse) was applied topically to the dorsal region every day for 19 weeks. Both solutions prevented an increase in skin thickness and reduction in skin elasticity caused by the UVB. The 3% solution also prevented wrinkles and melanin pigmentation as well as increases in the diameter and length of skin blood vessels. Increases in the expression of matrix metalloproteinase-2 (MMP-2) and vascular endothelial growth factor (VEGF) in UVB-irradiated skin was inhibited by the nonsugar fraction. Prevention of UVB-induced aging of the skin by topical application of the nonsugar fraction of brown sugar may be due to inhibition of increases in MMP-2 and VEGF expression.

  16. SGLT2 Inhibition by Empagliflozin Promotes Fat Utilization and Browning and Attenuates Inflammation and Insulin Resistance by Polarizing M2 Macrophages in Diet-induced Obese Mice

    Directory of Open Access Journals (Sweden)

    Liang Xu

    2017-06-01

    Full Text Available Sodium-glucose cotransporter (SGLT 2 inhibitors increase urinary glucose excretion (UGE, leading to blood glucose reductions and weight loss. However, the impacts of SGLT2 inhibition on energy homeostasis and obesity-induced insulin resistance are less well known. Here, we show that empagliflozin, a SGLT2 inhibitor, enhanced energy expenditure and attenuated inflammation and insulin resistance in high-fat-diet-induced obese (DIO mice. C57BL/6J mice were pair-fed a high-fat diet (HFD or a HFD with empagliflozin for 16 weeks. Empagliflozin administration increased UGE in the DIO mice, whereas it suppressed HFD-induced weight gain, insulin resistance, and hepatic steatosis. Moreover, empagliflozin shifted energy metabolism towards fat utilization, elevated AMP-activated protein kinase and acetyl-CoA carbolxylase phosphorylation in skeletal muscle, and increased hepatic and plasma fibroblast growth factor 21 levels. Importantly, empagliflozin increased energy expenditure, heat production, and the expression of uncoupling protein 1 in brown fat and in inguinal and epididymal white adipose tissue (WAT. Furthermore, empagliflozin reduced M1-polarized macrophage accumulation while inducing the anti-inflammatory M2 phenotype of macrophages within WAT and liver, lowering plasma TNFα levels and attenuating obesity-related chronic inflammation. Thus, empagliflozin suppressed weight gain by enhancing fat utilization and browning and attenuated obesity-induced inflammation and insulin resistance by polarizing M2 macrophages in WAT and liver.

  17. A non-enzymic browning induced by gamma cobalt-60 irradiation and heating in a fructose-alanine model system

    International Nuclear Information System (INIS)

    Bachman, S.; Zegota, A.; Zegota, H.

    1981-01-01

    The Maillard browning reaction between reducing sugars and amino compounds is important in food chemistry and may considerably affect the colour, aroma and nutritional value of food after thermal processing. In this study, the effect of irradiation combined with heating on the course of browning reaction in the model system of aqueous solution of fructose (0.03M) and alanine (0.01M) was investigated. The optical absorption spectra recorded for irradiated and heated solution of fructose-alanine were different from those of only irradiated or only heated solution. The brown colour of the samples is caused by the extension of the tail-end absorption into the visible region of the spectrum. No absorption maximum appears in the visible range. The heating of irradiated fructose solution with non-irradiated alanine develops markedly more intensive browning than that of the heating of irradiated alanine solution with non-irradiated fructose. The products of fructose radiolysis are responsible for the acceleration of browning in the fructose-alanine system. (author)

  18. Frequent extreme cold exposure and brown fat and cold-induced thermogenesis: a study in a monozygotic twin.

    Directory of Open Access Journals (Sweden)

    Maarten J Vosselman

    Full Text Available INTRODUCTION: Mild cold acclimation is known to increase brown adipose tissue (BAT activity and cold-induced thermogenesis (CIT in humans. We here tested the effect of a lifestyle with frequent exposure to extreme cold on BAT and CIT in a Dutch man known as 'the Iceman', who has multiple world records in withstanding extreme cold challenges. Furthermore, his monozygotic twin brother who has a 'normal' sedentary lifestyle without extreme cold exposures was measured. METHODS: The Iceman (subject A and his brother (subject B were studied during mild cold (13°C and thermoneutral conditions (31°C. Measurements included BAT activity and respiratory muscle activity by [18F]FDG-PET/CT imaging and energy expenditure through indirect calorimetry. In addition, body temperatures, cardiovascular parameters, skin perfusion, and thermal sensation and comfort were measured. Finally, we determined polymorphisms for uncoupling protein-1 and β3-adrenergic receptor. RESULTS: Subjects had comparable BAT activity (A: 1144 SUVtotal and B: 1325 SUVtotal, within the range previously observed in young adult men. They were genotyped with the polymorphism for uncoupling protein-1 (G/G. CIT was relatively high (A: 40.1% and B: 41.9%, but unlike during our previous cold exposure tests in young adult men, here both subjects practiced a g-Tummo like breathing technique, which involves vigorous respiratory muscle activity. This was confirmed by high [18F]FDG-uptake in respiratory muscle. CONCLUSION: No significant differences were found between the two subjects, indicating that a lifestyle with frequent exposures to extreme cold does not seem to affect BAT activity and CIT. In both subjects, BAT was not higher compared to earlier observations, whereas CIT was very high, suggesting that g-Tummo like breathing during cold exposure may cause additional heat production by vigorous isometric respiratory muscle contraction. The results must be interpreted with caution given the

  19. Brown dwarfs in retrogradely precessing cataclysmic variables?

    Directory of Open Access Journals (Sweden)

    Martin E.L.

    2011-07-01

    Full Text Available We compare Smoothed Particle Hydrodynamic simulations of retrogradely precessing accretion disks that have a white dwarf primary and a main sequence secondary with observational data and with theory on retrograde precession via tidal torques like those by the Moon and the Sun on the Earth [1, 2]. Assuming the primary does not accrete much of the mass lost from the secondary, we identify the theoretical low mass star/brown dwarf boundary. We find no observational candidates in our study that could qualify as brown dwarfs.

  20. Relevance of tidal heating on large TNOs

    Science.gov (United States)

    Saxena, Prabal; Renaud, Joe P.; Henning, Wade G.; Jutzi, Martin; Hurford, Terry

    2018-03-01

    We examine the relevance of tidal heating for large Trans-Neptunian Objects, with a focus on its potential to melt and maintain layers of subsurface liquid water. Depending on their past orbital evolution, tidal heating may be an important part of the heat budget for a number of discovered and hypothetical TNO systems and may enable formation of, and increased access to, subsurface liquid water. Tidal heating induced by the process of despinning is found to be particularly able to compete with heating due to radionuclide decay in a number of different scenarios. In cases where radiogenic heating alone may establish subsurface conditions for liquid water, we focus on the extent by which tidal activity lifts the depth of such conditions closer to the surface. While it is common for strong tidal heating and long lived tides to be mutually exclusive, we find this is not always the case, and highlight when these two traits occur together. We find cases where TNO systems experience tidal heating that is a significant proportion of, or greater than radiogenic heating for periods ranging from100‧s of millions to a billion years. For subsurface oceans that contain a small antifreeze component, tidal heating due to very high initial spin states may enable liquid water to be preserved right up to the present day. Of particular interest is the Eris-Dysnomia system, which in those cases may exhibit extant cryovolcanism.

  1. A system shift in tidal choking due to the construction of Yangshan Harbour, Shanghai, China

    Science.gov (United States)

    Guo, Wenyun; Wang, Xiao Hua; Ding, Pingxing; Ge, Jianzhong; Song, Dehai

    2018-06-01

    Tidal choking is a geometric feature caused by a narrowed channel. Construction of the Yangshan Harbour, Shanghai, China obstructed three key channels and intensively changed the local geometry and topography. In this study nine numerical experiments based on the Finite-Volume Community Ocean Model are conducted to study the project's influence on tidal characteristics. Results show that stronger tidal choking happened at the East Entrance after project, mainly due to the jet induced water-level drop forced by Bernoulli law and the longer and narrower geometry. The stronger tidal choking forces a faster flow and larger tidal energy flux at the choked channel while reducing the tidal amplitude in the Inner Harbour Area (IHA). The scouring on this channel reduces the choking effect but further enlarges tidal energy flux. Moreover, damming the channels decrease the tidal amplitude at the lee side of tidal propagating direction while increasing the amplitude on the stoss side. The dams also decrease the tidal current on both sides, and meanwhile develop two patches with stronger current aside the dam. The project induced changes in tidal characteristics are complex in space, and perturbations in bathymetry increase this complexity. Yangshan Harbour's construction induces little changes in the total tidal energy density in the IHA, but induces obvious changes in the spatial distribution of tidal energy. Although this study is site-specific, the findings may be applicable to tidal dynamics in land reclamation close to open seas, such as the dramatic reclamation of islands in the South China Sea.

  2. LEUKOCYTE COPING CAPACITY AS A TOOL TO ASSESS CAPTURE- AND HANDLING-INDUCED STRESS IN SCANDINAVIAN BROWN BEARS (URSUS ARCTOS).

    Science.gov (United States)

    Esteruelas, Núria Fandos; Huber, Nikolaus; Evans, Alina L; Zedrosser, Andreas; Cattet, Marc; Palomares, Francisco; Angel, Martine; Swenson, Jon E; Arnemo, Jon M

    2016-04-01

    Brown bears (Ursus arctos) are often captured and handled for research and management purposes. Although the techniques used are potentially stressful for the animals and might have detrimental and long-lasting consequences, it is difficult to assess their physiological impact. Here we report the use of the leukocyte coping capacity (LCC) technique to quantify the acute stress of capture and handling in brown bears in Scandinavia. In April and May 2012 and 2013, we collected venous blood samples and recorded a range of physiological variables to evaluate the effects of capture and the added impact of surgical implantation or removal of transmitters and sensors. We studied 24 brown bears, including 19 that had abdominal surgery. We found 1) LCC values following capture were lower in solitary bears than in bears in family groups suggesting capture caused relatively more stress in solitary bears, 2) ability to cope with handling stress was better (greater LCC values) in bears with good body condition, and 3) LCC values did not appear to be influenced by surgery. Although further evaluation of this technique is required, our preliminary results support the use of the LCC technique as a quantitative measure of stress.

  3. Brown Fat and Browning for the Treatment of Obesity and Related Metabolic Disorders

    Directory of Open Access Journals (Sweden)

    So Hun Kim

    2016-01-01

    Full Text Available Brown fat is a specialized fat depot that can increase energy expenditure and produce heat. After the recent discovery of the presence of active brown fat in human adults and novel transcription factors controlling brown adipocyte differentiation, the field of the study of brown fat has gained great interest and is rapidly growing. Brown fat expansion and/or activation results in increased energy expenditure and a negative energy balance in mice and limits weight gain. Brown fat is also able to utilize blood glucose and lipid and results in improved glucose metabolism and blood lipid independent of weight loss. Prolonged cold exposure and beta adrenergic agonists can induce browning of white adipose tissue. The inducible brown adipocyte, beige adipocyte evolving by thermogenic activation of white adipose tissue have different origin and molecular signature from classical brown adipocytes but share the characteristics of high mitochondria content, UCP1 expression and thermogenic capacity when activated. Increasing browning may also be an efficient way to increase whole brown fat activity. Recent human studies have shown possibilities that findings in mice can be reproduced in human, making brown fat a good candidate organ to treat obesity and its related disorders.

  4. Browns Ferry

    International Nuclear Information System (INIS)

    Wood, J.

    1996-01-01

    In 1986, the US Nuclear Regulatory Commission (NRC) established a ''watch list'' of power reactors requiring special attention which included the three BWR units at Brown's Ferry owned by the Tennessee Valley Authority (TVA). The reactors has been closed down voluntarily by the TVA in 1985 in order to deal with a backlog of maintenance and regulatory issues. Intended as short-term, the shutdown was indefinitely extended when the nature and extent of the design changes, accompanying documentation and retrofitting required to satisfy the NRC became apparent. The recovery programme for Unit 2 was completed by 1991 and the reactor returned to service under a dedicated operating staff. Meanwhile, a separate, dedicated, recovery team was set up to manage Unit 3 which was returned to service in December 1995. Browns Ferry 2 was removed from the NRC watch list in June 1992 and Units 1 and 3 in June 1996. Units 2 and 3 have both operated successfully since restart but Unit 1 is currently mothballed and TVA has no plans to bring it back into service. (UK)

  5. Responsiveness to Thyroid Hormone and to Ambient Temperature Underlies Differences Between Brown Adipose Tissue and Skeletal Muscle Thermogenesis in a Mouse Model of Diet-Induced Obesity

    Science.gov (United States)

    Ueta, Cintia B.; Olivares, Emerson L.

    2011-01-01

    Thyroid hormone accelerates energy expenditure (EE) and is critical for cold-induced thermogenesis. To define the metabolic role played by thyroid hormone in the dissipation of calories from diet, hypothyroid mice were studied for 60 d in a comprehensive lab animal monitoring system. Hypothyroidism decreased caloric intake and body fat while down-regulating genes in the skeletal muscle but not brown adipose tissue thermogenic programs, without affecting daily EE. Only at thermoneutrality (30 C) did hypothyroid mice exhibit slower rate of EE, indicating a metabolic response to hypothyroidism that depends on ambient temperature. A byproduct of this mechanism is that at room temperature (22 C), hypothyroid mice are protected against diet-induced obesity, i.e. only at thermoneutrality did hypothyroid mice become obese when placed on a high-fat diet (HFD). This is in contrast to euthyroid controls, which on a HFD gained more body weight and fat at any temperature while activating the brown adipose tissue and accelerating daily EE but not the skeletal muscle thermogenic program. In the liver of euthyroid controls, HFD caused an approximately 5-fold increase in triglyceride content and expression of key metabolic genes, whereas acclimatization to 30 C cut triglyceride content by half and normalized gene expression. However, in hypothyroid mice, HFD-induced changes in liver persisted at 30 C, resulting in marked liver steatosis. Acclimatization to thermoneutrality dramatically improves glucose homeostasis, but this was not affected by hypothyroidism. In conclusion, hypothyroid mice are metabolically sensitive to environmental temperature, constituting a mechanism that defines resistance to diet-induced obesity and hepatic lipid metabolism. PMID:21771890

  6. Tidally influenced alongshore circulation at an inlet-adjacent shoreline

    Science.gov (United States)

    Hansen, Jeff E.; Elias, Edwin P.L.; List, Jeffrey H.; Erikson, Li H.; Barnard, Patrick L.

    2013-01-01

    The contribution of tidal forcing to alongshore circulation inside the surfzone is investigated at a 7 km long sandy beach adjacent to a large tidal inlet. Ocean Beach in San Francisco, CA (USA) is onshore of a ∼150 km2 ebb-tidal delta and directly south of the Golden Gate, the sole entrance to San Francisco Bay. Using a coupled flow-wave numerical model, we find that the tides modulate, and in some cases can reverse the direction of, surfzone alongshore flows through two separate mechanisms. First, tidal flow through the inlet results in a barotropic tidal pressure gradient that, when integrated across the surfzone, represents an important contribution to the surfzone alongshore force balance. Even during energetic wave conditions, the tidal pressure gradient can account for more than 30% of the total alongshore pressure gradient (wave and tidal components) and up to 55% during small waves. The wave driven component of the alongshore pressure gradient results from alongshore wave height and corresponding setup gradients induced by refraction over the ebb-tidal delta. Second, wave refraction patterns over the inner shelf are tidally modulated as a result of both tidal water depth changes and strong tidal flows (∼1 m/s), with the effect from currents being larger. These tidally induced changes in wave refraction result in corresponding variability of the alongshore radiation stress and pressure gradients within the surfzone. Our results indicate that tidal contributions to the surfzone force balance can be significant and important in determining the direction and magnitude of alongshore flow.

  7. Ccl22/MDC, is a prostaglandin dependent pyrogen, acting in the anterior hypothalamus to induce hyperthermia via activation of brown adipose tissue.

    Science.gov (United States)

    Osborn, Olivia; Sanchez-Alavez, Manuel; Dubins, Jeffrey S; Gonzalez, Alejandro Sanchez; Morrison, Brad; Hadcock, John R; Bartfai, Tamas

    2011-03-01

    CC Chemokine ligand 22 (Ccl22) is a selective, high affinity ligand at the CC chemokine receptor 4 (Ccr4). We have identified cDNAs encoding both ligand and receptor of the Ccl22-Ccr4 pair in cDNA libraries of the anterior hypothalamus/pre-optic area (AH/POA) by PCR. The AH/POA is the key brain region where endogenous pyrogens have been shown to act on warm sensitive neurons to affect thermogenesis in brown adipose tissue (BAT) and other thermogenically responsive tissues. We show that functional Ccr4 receptors are present in the AH/POA neurons as injection of Ccl22 into the POA but not to other hypothalamic nuclei induces an increase in core body temperature as measured by radiotelemetry. Indomethacin (5 mg/kg s.c) pre-treatment markedly reduced the hyperthermia evoked by POA injection of Ccl22 (10 ng/0.5 ul) and thus suggests that this hyperthermia is mediated through cyclooxygenase activation and thus likely through the formation and action of the pyrogen prostaglandin E2. The temperature elevation involves a decrease in the respiratory exchange ratio and increased activation of the brown adipose tissue as demonstrated by ¹⁸F-FDG-PET imaging. We describe a novel role to the ligand Ccl22 and its receptor Ccr4 in the anterior hypothalamus in temperature regulation that depends on the synthesis of the endogenous pyrogen, prostaglandin E2. Copyright © 2010 Elsevier Ltd. All rights reserved.

  8. Deficiency in adipocyte chemokine receptor CXCR4 exacerbates obesity and compromises thermoregulatory responses of brown adipose tissue in a mouse model of diet-induced obesity

    Science.gov (United States)

    Yao, Longbiao; Heuser-Baker, Janet; Herlea-Pana, Oana; Zhang, Nan; Szweda, Luke I.; Griffin, Timothy M.; Barlic-Dicen, Jana

    2014-01-01

    The chemokine receptor CXCR4 is expressed on adipocytes and macrophages in adipose tissue, but its role in this tissue remains unknown. We evaluated whether deficiency in either adipocyte or myeloid leukocyte CXCR4 affects body weight (BW) and adiposity in a mouse model of high-fat-diet (HFD)-induced obesity. We found that ablation of adipocyte, but not myeloid leukocyte, CXCR4 exacerbated obesity. The HFD-fed adipocyte-specific CXCR4-knockout (AdCXCR4ko) mice, compared to wild-type C57BL/6 control mice, had increased BW (average: 52.0 g vs. 35.5 g), adiposity (average: 49.3 vs. 21.0% of total BW), and inflammatory leukocyte content in white adipose tissue (WAT), despite comparable food intake. As previously reported, HFD feeding increased uncoupling protein 1 (UCP1) expression (fold increase: 3.5) in brown adipose tissue (BAT) of the C57BL/6 control mice. However, no HFD-induced increase in UCP1 expression was observed in the AdCXCR4ko mice, which were cold sensitive. Thus, our study suggests that adipocyte CXCR4 limits development of obesity by preventing excessive inflammatory cell recruitment into WAT and by supporting thermogenic activity of BAT. Since CXCR4 is conserved between mouse and human, the newfound role of CXCR4 in mouse adipose tissue may parallel the role of this chemokine receptor in human adipose tissue.—Yao, L., Heuser-Baker, J., Herlea-Pana, O., Zhang, N., Szweda, L. I., Griffin, T. M., Barlic-Dicen, J. Deficiency in adipocyte chemokine receptor CXCR4 exacerbates obesity and compromises thermoregulatory responses of brown adipose tissue in a mouse model of diet-induced obesity. PMID:25016030

  9. Protective effects of pre-germinated brown rice diet on low levels of Pb-induced learning and memory deficits in developing rat.

    Science.gov (United States)

    Zhang, Rong; Lu, Hongzhi; Tian, Su; Yin, Jie; Chen, Qing; Ma, Li; Cui, Shijie; Niu, Yujie

    2010-03-30

    Lead (Pb) is a known neurotoxicant in humans and experimental animals. Numerous studies have provided evidence that humans, especially young children, and animals chronically intoxicated with low levels of Pb show learning and memory impairments. Unfortunately, Pb-poisoning cases continue to occur in many countries. Because the current treatment options are very limited, there is a need for alternative methods to attenuate Pb toxicity. In this study, the weaning (postnatal day 21, PND21) rats were randomly divided into five groups: the control group (AIN-93G diet, de-ionized water), the lead acetate (PbAC) group (AIN-93G diet, 2g/L PbAC in de-ionized water), the lead acetate+WR group (white rice diet, 2g/L PbAC in de-ionized water; PbAC+WR), the lead acetate+BR group (brown rice diet, 2g/L PbAC in de-ionized water; PbAC+BR) and the lead acetate+PR group (pre-germinated brown rice diet, 2g/L PbAC in de-ionized water; PbAC+PR). The animals received the different diets until PND60, and then the experiments were terminated. The protective effects of pre-germinated brown rice (PR) on Pb-induced learning and memory impairment in weaning rats were assessed by the Morris water maze and one-trial-learning passive avoidance test. The anti-oxidative effects of feeding a PR diet to Pb-exposed rats were evaluated. The levels of reactive oxygen species (ROS) were determined by flow cytometry. The levels of 8-hydroxy-2-deoxyguanosine (8-OHdG), gamma-aminobutyric acid (GABA) and glutamate were determined by HPLC. Our data showed that feeding a PR diet decreased the accumulation of lead and decreased Pb-induced learning and memory deficits in developing rats. The mechanisms might be related to the anti-oxidative effects and large amount of GABA in PR. Our study provides a regimen to reduce Pb-induced toxicity, especially future learning and memory deficits in the developing brain.

  10. Tidal alignment of galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Blazek, Jonathan; Vlah, Zvonimir; Seljak, Uroš

    2015-08-01

    We develop an analytic model for galaxy intrinsic alignments (IA) based on the theory of tidal alignment. We calculate all relevant nonlinear corrections at one-loop order, including effects from nonlinear density evolution, galaxy biasing, and source density weighting. Contributions from density weighting are found to be particularly important and lead to bias dependence of the IA amplitude, even on large scales. This effect may be responsible for much of the luminosity dependence in IA observations. The increase in IA amplitude for more highly biased galaxies reflects their locations in regions with large tidal fields. We also consider the impact of smoothing the tidal field on halo scales. We compare the performance of this consistent nonlinear model in describing the observed alignment of luminous red galaxies with the linear model as well as the frequently used "nonlinear alignment model," finding a significant improvement on small and intermediate scales. We also show that the cross-correlation between density and IA (the "GI" term) can be effectively separated into source alignment and source clustering, and we accurately model the observed alignment down to the one-halo regime using the tidal field from the fully nonlinear halo-matter cross correlation. Inside the one-halo regime, the average alignment of galaxies with density tracers no longer follows the tidal alignment prediction, likely reflecting nonlinear processes that must be considered when modeling IA on these scales. Finally, we discuss tidal alignment in the context of cosmic shear measurements.

  11. Salinity-Induced Callus Browning and Re-Differentiation, Root Formation by Plantlets and Anatomical Structures of Plantlet Leaves in Two Malus Species

    International Nuclear Information System (INIS)

    Gou, W.; Zheng, P.; Zheng, P.; Wang, K.; Zhang, L.; Akram, N. A.

    2016-01-01

    Apple (Malus domestica L.) is widely grown in northern China. However, soil salinization has become one of the most severe factors limiting apple productivity in some regions including the Loess Plateau. In our study, the regeneration system of both rootstock Rehd (Malus robusta Rehd) and scion Fuji (Malus domestica Borkh. cv. Fuji) was established In vitro. The two Malus species were cultured on the MS medium containing 0 or 150 mM NaCl to examine salt-induced effects on callus browning and re-differentiation, root formation of plantlets and anatomical structures of plantlet leaves at 15 days old callus and plantlet stages. Salt stress caused a marked increase in callus browning rate, while a decrease in re-differentiation rate, rooting rate, root number and length in both species. Additionally, anatomical structures of plantlet leave showed salt-induced damage such as reduced palisade tissue and intracellular chloroplast, incomplete development of xylem and severe damage of the phloem tissue. Salt stress also caused a few adaptive structural features in leaves including increased thickness of upper and lower epidermis, elevated proportion of spongy tissue and formation of lignified vessels. The responses of the two Malus species did not differ significantly at the differentiation stage. However, they were more sensitive to salinity at the callus stage than those at the plantlet stage in each species. Therefore, callus stage has been found to be more suitable for evaluating responses of the two apple species to salt stress. The Fuji and Rehd could be treated as a good scion/rootstock combination of apple to adapt to soil salinity based on their similar degree of salt stress-tolerance. (author)

  12. Turbidity maximum formation in a well-mixed macrotidal estuary : The role of tidal pumping

    NARCIS (Netherlands)

    Yu, Q.; Wang, Y.; Gao, J.; Gao, S.; Flemming, B.

    2014-01-01

    Traditionally, vertical circulation (induced by gravity circulation and tidal straining), tidal pumping, and resuspension are suggested as the major processes for the formation and maintenance of the estuarine turbidity maximum (ETM). Due to strong mixing, tidal pumping is considered as the

  13. Tidally Heated Terrestrial Exoplanets

    Science.gov (United States)

    Henning, Wade Garrett

    This work models the surface and internal temperatures for hypothetical terrestrial planets in situations involving extreme tidal heating. The feasibility of such planets is evaluated in terms of the orbital perturbations that may give rise to them, their required proximity to a hoststar, and the potential for the input tidal heating to cause significant partial melting of the mantle. Trapping terrestrial planets into 2:1 resonances with migrating Hot Jupiters is considered as a reasonable way for Earth-like worlds to both maintain high eccentricities and to move to short enough orbital periods (1-20 days) for extreme tidal heating to occur. Secular resonance and secular orbital perturbations may support moderate tidal heating at a low equilibrium eccentricity. At orbital periods below 10-30 days, with eccentricities from 0.01 to 0.1, tidal heat may greatly exceed radiogenic heat production. It is unlikely to exceed insolation, except when orbiting very low luminosity hosts, and thus will have limited surface temperature expression. Observations of such bodies many not be able to detect tidal surface enhancements given a few percent uncertainty in albedo, except on the nightside of spin synchronous airless objects. Otherwise detection may occur via spectral detection of hotspots or high volcanic gas concentrations including sulfur dioxide and hydrogen sulfide. The most extreme cases may be able to produce magma oceans, or magma slush mantles with up to 40-60% melt fractions. Tides may alter the habitable zones for smaller red dwarf stars, but are generally detrimental. Multiple viscoelastic models, including the Maxwell, Voigt-Kelvin, Standard Anelastic Solid, and Burgers rheologies are explored and applied to objects such as Io and the super-Earth planet GJ 876d. The complex valued Love number for the Burgers rheology is derived and found to be a useful improvement when modeling the low temperature behavior of tidal bodies, particularly during low eccentricity

  14. PKA-RIIB Deficiency Induces Brown Fatlike Adipocytes in Inguinal WAT and Promotes Energy Expenditure in Male FVB/NJ Mice.

    Science.gov (United States)

    Su, Jing; Wu, Wei; Huang, Shan; Xue, Ruidan; Wang, Yi; Wan, Yun; Zhang, Lv; Qin, Lang; Zhang, Qiongyue; Zhu, Xiaoming; Zhang, Zhaoyun; Ye, Hongying; Wu, Xiaohui; Li, Yiming

    2017-03-01

    Obesity has become the most common metabolic disorder worldwide. Promoting brown adipose tissue (BAT) and beige adipose tissue formation, and therefore, a functional increase in energy expenditure, may counteract obesity. Mice lacking type IIβ regulatory subunit of adenosine 3',5' cyclic monophosphate (cAMP)-dependent protein kinase A (PKA-RIIB) display reduced adiposity and resistance to diet-induced obesity. PKA-RIIB, encoded by the Prkar2b gene, is most abundant in BAT and white adipose tissue (WAT) and in the brain. In this study, we show that mice lacking PKA-RIIB have increased energy expenditure, limited weight gain, and improved glucose metabolism. PKA-RIIB deficiency induces brownlike adipocyte in inguinal WAT (iWAT). PKA-RIIB deficiency also increases the expression of uncoupling protein 1 and other thermogenic genes in iWAT and primary preadipocytes from iWAT through a mechanism involving increased PKA activity, which is represented by increased phosphorylation of PKA substrate, cAMP response element binding protein, and P38 mitogen-activated protein kinase. Our study provides evidence for the role of PKA-RIIB deficiency in regulating thermogenesis in WAT, which may potentially have therapeutic implications for the treatment of obesity and related metabolic disorders. Copyright © 2017 by the Endocrine Society.

  15. Environmental consequences of tidal power in a hyper-tidal muddy regime: the Severn estuary

    International Nuclear Information System (INIS)

    Kirby, R.

    1997-01-01

    Muddy hyper-tidal regimes, such as the Severn Estuary in the UK, are especially difficult for plants and animals. The difficulties stem from the semi-diurnal and semi-lunar energy fluctuations. On spring tides entrained fine sediment induces elevated suspended sediment concentrations such that photosynthesis is inhibited. On neap tides much of the entrained fine sediment is deposited on the sub-tidal bed over periods of several days to form ephemeral dense layers, which reach in excess of 100 G/l and rapidly become anaerobic on stagnation. Such occasional bed faunas as develop are characterised by very large numbers of immature individuals of a few species. One of the few organisms able to cope with the extreme conditions is the siliceous reef-building worn Sabellaria. Arising from the long term suppression in its calcareous fauna, erosion and winnowing of these Holocene clays fails to give rise to lag shell deposits, called chenier ridges, found elsewhere in eroding muddy inter-tidal systems. A tidal power barrage would shift the regime from hyper-tidal to macro-tidal decrease in turbidity would permit photosynthesis and phytoplankton growth, so stimulating the higher food chain. Ironically, perhaps, cleaning up the sewage discharges in the estuary, in the absence of barrage construction would lead to a wading bird crash whereas barrage construction would lead to an improved carrying capacity. (author)

  16. A numerical study of local variations in tidal regime of Tagus estuary, Portugal.

    Science.gov (United States)

    Dias, João Miguel; Valentim, Juliana Marques; Sousa, Magda Catarina

    2013-01-01

    Tidal dynamics of shallow estuaries and lagoons is a complex matter that has attracted the attention of a large number of researchers over the last few decades. The main purpose of the present work is to study the intricate tidal dynamics of the Tagus estuary, which states as the largest estuary of the Iberian Peninsula and one of the most important wetlands in Portugal and Europe. Tagus has large areas of low depth and a remarkable geomorphology, both determining the complex propagation of tidal waves along the estuary of unknown manner. A non-linear two-dimensional vertically integrated hydrodynamic model was considered to be adequate to simulate its hydrodynamics and an application developed from the SIMSYS2D model was applied to study the tidal propagation along the estuary. The implementation and calibration of this model revealed its accuracy to predict tidal properties along the entire system. Several model runs enabled the analysis of the local variations in tidal dynamics, through the interpretation of amplitude and phase patterns of the main tidal constituents, tidal asymmetry, tidal ellipses, form factor and tidal dissipation. Results show that Tagus estuary tidal dynamics is extremely dependent on an estuarine resonance mode for the semi-diurnal constituents that induce important tidal characteristics. Besides, the estuarine coastline features and topography determines the changes in tidal propagation along the estuary, which therefore result essentially from a balance between convergence/divergence and friction and advection effects, besides the resonance effects.

  17. Coastal inlets and tidal basins

    NARCIS (Netherlands)

    De Vriend, H.J.; Dronkers, J.; Stive, M.J.F.; Van Dongeren, A.; Wang, J.H.

    2002-01-01

    lecture note: Tidal inlets and their associated basins (lagoons) are a common feature of lowland coasts all around the world. A significant part ofthe world's coastlines is formed by barrier island coasts, and most other tidal coasts are interrupted by estuaries and lagoon inlets. These tidal

  18. Homogeneous wave turbulence driven by tidal flows

    Science.gov (United States)

    Favier, B.; Le Reun, T.; Barker, A.; Le Bars, M.

    2017-12-01

    When a moon orbits around a planet, the rotation of the induced tidal bulge drives a homogeneous, periodic, large-scale flow. The combination of such an excitation with the rotating motion of the planet has been shown to drive parametric resonance of a pair of inertial waves in a mechanism called the elliptical instability. Geophysical fluid layers can also be stratified: this is the case for instance of the Earth's oceans and, as suggested by several studies, of the upper part of the Earth's liquid Outer Core. We thus investigate the stability of a rotating and stratified layer undergoing tidal distortion in the limit where either rotation or stratification is dominant. We show that the periodic tidal flow drives a parametric subharmonic resonance of inertial (resp. internal) waves in the rotating (resp. stratified) case. The instability saturates into a wave turbulence pervading the whole fluid layer. In such a state, the instability mechanism conveys the tidal energy from the large scale tidal flow to the resonant modes, which then feed a succession of triadic resonances also generating small spatial scales. In the rotating case, we observe a kinetic energy spectrum with a k-2 slope for which the Coriolis force is dominant at all spatial scales. In the stratified case, where the timescale separation is increased between the tidal excitation and the Brunt-Väisälä frequencies, the temporal spectrum decays with a ω-2 power law up to the cut-off frequency beyond which waves do not exist. This result is reminiscent of the Garrett and Munk spectrum measured in the oceans and theoretically described as a manifestation of internal wave turbulence. In addition to revealing an instability driving homogeneous turbulence in geophysical fluid layers, our approach is also an efficient numerical tool to investigate the possibly universal properties of wave turbulence in a geophysical context.

  19. [Human brown adipose tissue].

    Science.gov (United States)

    Virtanen, Kirsi A; Nuutila, Pirjo

    2015-01-01

    Adult humans have heat-producing and energy-consuming brown adipose tissue in the clavicular region of the neck. There are two types of brown adipose cells, the so-called classic and beige adipose cells. Brown adipose cells produce heat by means of uncoupler protein 1 (UCP1) from fatty acids and sugar. By applying positron emission tomography (PET) measuring the utilization of sugar, the metabolism of brown fat has been shown to multiply in the cold, presumably influencing energy consumption. Active brown fat is most likely present in young adults, persons of normal weight and women, least likely in obese persons.

  20. The Effect of Sulfated (1→3-α-l-Fucan from the Brown Alga Saccharina cichorioides Miyabe on Resveratrol-Induced Apoptosis in Colon Carcinoma Cells

    Directory of Open Access Journals (Sweden)

    Olesia S. Vishchuk

    2013-01-01

    Full Text Available Accumulating data clearly indicate that the induction of apoptosis by nontoxic natural compounds is a potent defense against the development and progression of many malignancies, including colon cancer. Resveratrol and the fucoidans have been shown to possess potent anti-tumor activity in vitro and in vivo. The aim of the present study was to examine whether the combination of a fucoidan from the brown alga Saccharina cichorioides Miyabe and resveratrol would be an effective preventive and/or therapeutic strategy against colon cancer. Based on NMR spectroscopy and MALDI-TOF analysis, the fucoidan isolated and purified from Saccharina cichorioides Miyabe was (1→3-α-l-fucan with sulfate groups at C2 and C4 of the α-l-fucopyranose residues. The fucoidan enhanced the antiproliferative activity of resveratrol at nontoxic doses and facilitated resveratrol-induced apoptosis in the HCT 116 human colon cancer cell line. Apoptosis was realized by the activation of initiator caspase-9 and effector caspase-7 and -3, followed by the cleavage of PARP. Furthermore, significant inhibition of HCT 116 colony formation was associated with the sensitization of cells to resveratrol by the fucoidan. Taken together, these results demonstrate that the combination of the algal fucoidan with resveratrol may provide a potential therapy against human colon cancer.

  1. Co-ordinate decrease in the expression of the mitochondrial genome and nuclear genes for mitochondrial proteins in the lactation-induced mitochondrial hypotrophy of rat brown fat.

    Science.gov (United States)

    Martin, I; Giralt, M; Viñas, O; Iglesias, R; Mampel, T; Villarroya, F

    1995-01-01

    The relative abundance of the mitochondrial-encoded mRNAs for cytochrome c oxidase subunit II and NADH dehydrogenase subunit I was lower in brown adipose tissue (BAT) from lactating rats than in virgin controls. This decrease was in parallel with a significant decrease in mitochondrial 16 S rRNA levels and in the relative content of mitochondrial DNA in the tissue. BAT from lactating rats showed lowered mRNA expression of the nuclear-encoded genes for the mitochondrial uncoupling protein, subunit IV of cytochrome c oxidase and the adenine nucleotide translocase isoforms ANT1 and ANT2, whereas mRNA levels for the ATP synthase beta-subunit were unchanged. However, the relative content of this last protein was lower in BAT mitochondria from lactating rats than in virgin controls. It is concluded that lactation-induced mitochondrial hypotrophy in BAT is associated with a co-ordinate decrease in the expression of the mitochondrial genome and nuclear genes for mitochondrial proteins. This decrease is caused by regulatory events acting at different levels, including pre- and post-transcriptional regulation. BAT appears to be a useful model with which to investigate the molecular mechanisms involved in the co-ordination of the expression of the mitochondrial and nuclear genomes during mitochondrial biogenesis. Images Figure 1 Figure 2 PMID:8948428

  2. A low-protein diet induces body weight loss and browning of subcutaneous white adipose tissue through enhanced expression of hepatic fibroblast growth factor 21 (FGF21).

    Science.gov (United States)

    Pérez-Martí, Albert; Garcia-Guasch, Maite; Tresserra-Rimbau, Anna; Carrilho-Do-Rosário, Alexandra; Estruch, Ramon; Salas-Salvadó, Jordi; Martínez-González, Miguel Ángel; Lamuela-Raventós, Rosa; Marrero, Pedro F; Haro, Diego; Relat, Joana

    2017-08-01

    Fibroblast growth factor 21 (FGF21) is considered a promising therapeutic candidate for the treatment of obesity. Since FGF21 production is regulated by various nutritional factors, we analyze the impact of low protein intake on circulating levels of this growth hormone in mice and in a sub cohort of the PREDIMED (Prevención con Dieta Mediterránea) trial. We also describe the role of hepatic FGF21 in metabolic adaptation to a low-protein diet (LPD). We fed control and liver-specific Fgf21 knockout (LFgf21KO) mice a LPD. This diet increased FGF21 production by inducing its overexpression in liver, and this correlated with a body weight decrease without changes in food intake. The LPD also caused FGF21-dependent browning in subcutaneous white adipose tissue (scWAT), as indicated by an increase in the expression of uncoupling protein 1 (UCP1). In a subgroup of 78 individuals from the PREDIMED trial, we observed an inverse correlation between protein intake and circulating FGF21 levels. Our results reinforce the involvement of FGF21 in coordinating energy homeostasis under a range of nutritional conditions. Moreover, here we describe an approach to increase the endogenous production of FGF21, which if demonstrated functional in humans, could generate a treatment for obesity. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Protective effect of the edible brown alga Ecklonia stolonifera on doxorubicin-induced hepatotoxicity in primary rat hepatocytes.

    Science.gov (United States)

    Jung, Hyun Ah; Kim, Jae-I; Choung, Se Young; Choi, Jae Sue

    2014-08-01

    As part of our efforts to isolate anti-hepatotoxic agents from marine natural products, we screened the ability of 14 edible varieties of Korean seaweed to protect against doxorubicin-induced hepatotoxicity in primary rat hepatocytes. Among the crude extracts of two Chlorophyta (Codium fragile and Capsosiphon fulvescens), seven Phaeophyta (Undaria pinnatifida, Sargassum thunbergii, Pelvetia siliquosa, Ishige okamurae, Ecklonia cava, Ecklonia stolonifera and Eisenia bicyclis), five Rhodophyta (Chondrus ocellatus, Gelidium amansii, Gracilaria verrucosa, Symphycladia latiuscula and Porphyra tenera), and the extracts of Ecklonia stolonifera, Ecklonia cava, Eisenia bicyclis and Pelvetia siliquosa exhibited significant protective effects on doxorubicin-induced hepatotoxicity, with half maximal effective concentration (EC50) values of 2.0, 2.5, 3.0 and 15.0 μg/ml, respectively. Since Ecklonia stolonifera exhibits a significant protective potential and is frequently used as foodstuff, we isolated six phlorotannins, including phloroglucinol (1), dioxinodehydroeckol (2), eckol (3), phlorofucofuroeckol A (4), dieckol (5) and triphloroethol-A (6). Phlorotannins 2 ∼ 6 exhibited potential protective effects on doxorubicin-induced hepatotoxicity, with corresponding EC50 values of 3.4, 8.3, 4.4, 5.5 and 11.5 μg/ml, respectively. The results clearly demonstrated that the anti-hepatotoxic effects of Ecklonia stolonifera and its isolated phlorotannins are useful for further exploration and development of therapeutic modalities for treatment of hepatotoxicity. © 2014 Royal Pharmaceutical Society.

  4. In brown adipocytes, adrenergically induced β1-/β3-(Gs)-, α2-(Gi)- and α1-(Gq)-signalling to Erk1/2 activation is not mediated via EGF receptor transactivation

    International Nuclear Information System (INIS)

    Wang, Yanling; Fälting, Johanna M.; Mattsson, Charlotte L.; Holmström, Therése E.; Nedergaard, Jan

    2013-01-01

    Brown adipose tissue is unusual in that the neurotransmitter norepinephrine influences cell destiny in ways generally associated with effects of classical growth factors: regulation of cell proliferation, of apoptosis, and progression of differentiation. The norepinephrine effects are mediated through G-protein-coupled receptors; further mediation of such stimulation to e.g. Erk1/2 activation is in cell biology in general accepted to occur through transactivation of the EGF receptor (by external or internal pathways). We have examined here the significance of such transactivation in brown adipocytes. Stimulation of mature brown adipocytes with cirazoline (α 1 -adrenoceptor coupled via G q ), clonidine (α 2 via G i ) or CL316243 (β 3 via G s ) or via β 1 -receptors significantly activated Erk1/2. Pretreatment with the EGF receptor kinase inhibitor AG1478 had, remarkably, no significant effect on Erk1/2 activation induced by any of these adrenergic agonists (although it fully abolished EGF-induced Erk1/2 activation), demonstrating absence of EGF receptor-mediated transactivation. Results with brown preadipocytes (cells in more proliferative states) were not qualitatively different. Joint stimulation of all adrenoceptors with norepinephrine did not result in synergism on Erk1/2 activation. AG1478 action on EGF-stimulated Erk1/2 phosphorylation showed a sharp concentration–response relationship (IC 50 0.3 µM); a minor apparent effect of AG1478 on norepinephrine-stimulated Erk1/2 phosphorylation showed nonspecific kinetics, implying caution in interpretation of partial effects of AG1478 as reported in other systems. Transactivation of the EGF receptor is clearly not a universal prerequisite for coupling of G-protein coupled receptors to Erk1/2 signalling cascades. - Highlights: • In brown adipocytes, norepinephrine regulates proliferation, apoptosis, differentiation. • EGF receptor transactivation is supposed to mediate GPCR-induced Erk1/2 activation. •

  5. Dynamics of Tidally Locked, Ultrafast Rotating Atmospheres

    Science.gov (United States)

    Tan, Xianyu; Showman, Adam P.

    2017-10-01

    Tidally locked gas giants, which exhibit a novel regime of day-night thermal forcing and extreme stellar irradiation, are typically in several-day orbits, implying slow rotation and a modest role for rotation in the atmospheric circulation. Nevertheless, there exist a class of gas-giant, highly irradiated objects - brown dwarfs orbiting white dwarfs in extremely tight orbits - whose orbital and hence rotation periods are as short as 1-2 hours. Spitzer phase curves and other observations have already been obtained for this fascinating class of objects, which raise fundamental questions about the role of rotation in controlling the circulation. So far, most modeling studies have investigated rotation periods exceeding a day, as appropriate for typical hot Jupiters. In this work we investigate the dynamics of tidally locked atmospheres in shorter rotation periods down to about two hours. With increasing rotation rate (decreasing rotation period), we show that the width of the equatorial eastward jet decreases, consistent with the narrowing of wave-mean-flow interacting region due to decrease of the equatorial deformation radius. The eastward-shifted equatorial hot spot offset decreases accordingly, and the westward-shifted hot regions poleward of the equatorial jet associated with Rossby gyres become increasingly distinctive. At high latitudes, winds becomes weaker and more geostrophic. The day-night temperature contrast becomes larger due to the stronger influence of rotation. Our simulated atmospheres exhibit small-scale variability, presumably caused by shear instability. Unlike typical hot Jupiters, phase curves of fast-rotating models show an alignment of peak flux to secondary eclipse. Our results have important implications for phase curve observations of brown dwarfs orbiting white dwarfs in ultra tight orbits.

  6. Laboratory experiments examining inducible defense show variable responses of temperate brown and red macroalgae Experimentos de laboratorio para examinar las defensas inducibles muestran respuestas variables en macroalgas pardas y rojas de ambientes templados

    Directory of Open Access Journals (Sweden)

    EVA ROTHÄUSLER

    2005-12-01

    Full Text Available Macroalgae can defend themselves against generalist and specialist herbivores via morphological and/or chemical traits. Herein we examined the defensive responses (via relative palatability of two brown (Lessonia nigrescens, Glossophora kunthii and two red algae (Grateloupia doryphora, Chondracanthus chamissoi from the northern-central coast of Chile against selected generalist meso-herbivores. Two laboratory experiments were conducted to investigate whether (i algae can respond generally to grazing pressure of meso-herbivores (amphipods, isopods and juvenile sea urchins and whether (ii these algal responses were inducible. In order to examine palatability and thus effectiveness of responses, feeding assays were run after each experiment using fresh algal pieces and artificial agar-based food. Lessonia nigrescens responded to amphipods but not to sea urchins, and G. kunthii showed inducible response against one species of amphipods. Grateloupia doryphora did not respond against any of the tested grazers, whereas C. chamissoi responded against one species of amphipods and the tested isopod. Our results indicate variable responses of macroalgae against selected generalist meso-herbivores and evidence of an inducible defense in the brown alga G. kunthii.Muchas macroalgas poseen la capacidad de defenderse contra herbívoros generalistas y especialistas utilizando defensas químicas y/o morfológicas. En este trabajo se examinó la respuesta de la palatabilidad ante meso-herbívoros generalistas de dos algas pardas (Lessonia nigrescens, Glossophora kunthii y dos algas rojas (Grateloupia doryphora, Chondracanthus chamissoi de la costa Norte de Chile. Se realizaron dos experimentos de laboratorio para investigar si: (i las algas pueden responder al pastoreo realizado por meso-herbivoros generalistas (anfípodos, isópodos y erizos juveniles y (ii si la respuesta de estas algas es inducible. Para examinar la palatabilidad y de esta forma la efectividad

  7. Relativistic tidal properties of neutron stars

    International Nuclear Information System (INIS)

    Damour, Thibault; Nagar, Alessandro

    2009-01-01

    We study the various linear responses of neutron stars to external relativistic tidal fields. We focus on three different tidal responses, associated to three different tidal coefficients: (i) a gravito-electric-type coefficient Gμ l =[length] 2l+1 measuring the lth-order mass multipolar moment GM a 1 ...a l induced in a star by an external lth-order gravito-electric tidal field G a 1 ...a l ; (ii) a gravito-magnetic-type coefficient Gσ l =[length] 2l+1 measuring the lth spin multipole moment GS a 1 ...a l induced in a star by an external lth-order gravito-magnetic tidal field H a 1 ...a l ; and (iii) a dimensionless 'shape' Love number h l measuring the distortion of the shape of the surface of a star by an external lth-order gravito-electric tidal field. All the dimensionless tidal coefficients Gμ l /R 2l+1 , Gσ l /R 2l+1 , and h l (where R is the radius of the star) are found to have a strong sensitivity to the value of the star's 'compactness'c≡GM/(c 0 2 R) (where we indicate by c 0 the speed of light). In particular, Gμ l /R 2l+1 ∼k l is found to strongly decrease, as c increases, down to a zero value as c is formally extended to the 'black hole (BH) limit'c BH =1/2. The shape Love number h l is also found to significantly decrease as c increases, though it does not vanish in the formal limit c→c BH , but is rather found to agree with the recently determined shape Love numbers of black holes. The formal vanishing of μ l and σ l as c→c BH is a consequence of the no-hair properties of black holes. This vanishing suggests, but in no way proves, that the effective action describing the gravitational interactions of black holes may not need to be augmented by nonminimal worldline couplings.

  8. Prehospital tidal volume influences hospital tidal volume: A cohort study.

    Science.gov (United States)

    Stoltze, Andrew J; Wong, Terrence S; Harland, Karisa K; Ahmed, Azeemuddin; Fuller, Brian M; Mohr, Nicholas M

    2015-06-01

    The purposes of the study are to describe current practice of ventilation in a modern air medical system and to measure the association of ventilation strategy with subsequent ventilator care and acute respiratory distress syndrome (ARDS). Retrospective observational cohort study of intubated adult patients (n = 235) transported by a university-affiliated air medical transport service to a 711-bed tertiary academic center between July 2011 and May 2013. Low tidal volume ventilation was defined as tidal volumes less than or equal to 8 mL/kg predicted body weight. Multivariable regression was used to measure the association between prehospital tidal volume, hospital ventilation strategy, and ARDS. Most patients (57%) were ventilated solely with bag valve ventilation during transport. Mean tidal volume of mechanically ventilated patients was 8.6 mL/kg predicted body weight (SD, 0.2 mL/kg). Low tidal volume ventilation was used in 13% of patients. Patients receiving low tidal volume ventilation during air medical transport were more likely to receive low tidal volume ventilation in the emergency department (P tidal volume (P = .840). Low tidal volume ventilation was rare during air medical transport. Air transport ventilation strategy influenced subsequent ventilation but was not associated with ARDS. Copyright © 2015 Elsevier Inc. All rights reserved.

  9. The cold-induced lipokine 12,13-diHOME promotes fatty acid transport into brown adipose tissue

    DEFF Research Database (Denmark)

    Lynes, Matthew D; Leiria, Luiz O; Lundh, Morten

    2017-01-01

    and glucose tolerance; as a class, these lipids are referred to as 'lipokines'. Because BAT is a specialized metabolic tissue that takes up and burns lipids and is linked to systemic metabolic homeostasis, we hypothesized that there might be thermogenic lipokines that activate BAT in response to cold. Here we...... show that the lipid 12,13-dihydroxy-9Z-octadecenoic acid (12,13-diHOME) is a stimulator of BAT activity, and that its levels are negatively correlated with body-mass index and insulin sensitivity. Using a global lipidomic analysis, we found that 12,13-diHOME was increased in the circulation of humans...... and mice exposed to cold. Furthermore, we found that the enzymes that produce 12,13-diHOME were uniquely induced in BAT by cold stimulation. The injection of 12,13-diHOME acutely activated BAT fuel uptake and enhanced cold tolerance, which resulted in decreased levels of serum triglycerides...

  10. Tidal power: trends and developments

    International Nuclear Information System (INIS)

    1992-01-01

    This volume covers works and studies on tidal power currently being undertaken, both nationally and internationally. The 20 papers included cover the proposed Mersey barrage, the Severn estuary and several papers on the Severn barrage. The Department of Energy's continued variety of generic work on tidal power and various overseas studies carried out by other experts are also detailed, giving the reader an up to date picture of developments in tidal power worldwide. Separate abstracts have been prepared for the individual papers. (author)

  11. In utero exposure to germinated brown rice and its oryzanol-rich extract attenuated high fat diet-induced insulin resistance in F1 generation of rats.

    Science.gov (United States)

    Adamu, Hadiza Altine; Imam, Mustapha Umar; Ooi, Der-Jiun; Esa, Norhaizan Mohd; Rosli, Rozita; Ismail, Maznah

    2017-01-21

    The development of insulin resistance is multifactorial, with maternal pre- and postnatal nutrition having significant influences. In this regard, high fat diet (HFD) feeding in pregnancy has been shown to increase risks of metabolic diseases. Thus, we investigated the effects of supplementation of HFD with germinated brown rice (GBR) and GBR-derived gamma oryzanol-rich extract (OE) on insulin resistance and its epigenetic implications in pregnant rats and their offsprings. Pregnant female Sprague dawley rats were fed with HFD alone, HFD + GBR or HFD + OE (100 or 200 mg/kg/day) throughout pregnancy and lactation. Their offsprings were weaned at 4 weeks post-delivery and were followed up until 8 weeks. Serum levels of adipokines were measured in dams and their offsprings, and global DNA methylation and histone acetylation patterns were estimated from the liver. The dams and offsprings of the GBR and OE groups had lower weight gain, glycemic response, 8-Iso prostaglandin, retinol binding protein 4 and fasting insulin, and elevated adiponectin levels compared with the HFD group. Fasting leptin levels were lower only in the GBR groups. Hepatic global DNA methylation was lower in the GBR groups while hepatic H4 acetylation was lower in both GBR and OE dams. In the offsprings, DNA methylation and H4 acetylation were only lower in the OE group. However, dams and offsprings of the GBR and OE groups had higher hepatic H3 acetylation. GBR and OE can be used as functional ingredients for the amelioration of HFD-induced epigeneticallymediated insulin resistance.

  12. Observed tidal braking in the earth/moon/sun system

    Science.gov (United States)

    Christodoulidis, D. C.; Smith, D. E.; Williamson, R. G.; Klosko, S. M.

    1987-01-01

    The low degree and order terms in the spherical harmonic model of the tidal potential were observed through the perturbations which are induced on near-earth satellite orbital motions. Evaluations of tracking observations from 17 satellites and a GEM-T1 geopotential model were used in the tidal recovery which was made in the presence of over 600 long-wavelength coefficients from 32 major and minor tides. Wahr's earth tidal model was used as a basis for the recovery of the ocean tidal terms. Using this tidal model, the secular change in the moon's mean motion due to tidal dissipation was found to be -25.27 + or - 0.61 arcsec/century squared. The estimation of lunar acceleration agreed with that observed from lunar laser ranging techniques (-24.9 + or - 1.0 arcsec/century squared), with the corresponding tidal braking of earth's rotation being -5.98 + or - 0.22 x 10 to the minus 22 rad/second squared. If the nontidal braking of the earth due to the observed secular change in the earth's second zonal harmonic is considered, satellite techniques yield a total value of the secular change of the earth's rotation rate of -4.69 + or - 0.36 x 10 to the minus 22 rad/second squared.

  13. Magnetic fields driven by tidal mixing in radiative stars

    Science.gov (United States)

    Vidal, Jérémie; Cébron, David; Schaeffer, Nathanaël; Hollerbach, Rainer

    2018-04-01

    Stellar magnetism plays an important role in stellar evolution theory. Approximatively 10 per cent of observed main sequence (MS) and pre-main-sequence (PMS) radiative stars exhibit surface magnetic fields above the detection limit, raising the question of their origin. These stars host outer radiative envelopes, which are stably stratified. Therefore, they are assumed to be motionless in standard models of stellar structure and evolution. We focus on rapidly rotating, radiative stars which may be prone to the tidal instability, due to an orbital companion. Using direct numerical simulations in a sphere, we study the interplay between a stable stratification and the tidal instability, and assess its dynamo capability. We show that the tidal instability is triggered regardless of the strength of the stratification (Brunt-Väisälä frequency). Furthermore, the tidal instability can lead to both mixing and self-induced magnetic fields in stably stratified layers (provided that the Brunt-Väisälä frequency does not exceed the stellar spin rate in the simulations too much). The application to stars suggests that the resulting magnetic fields could be observable at the stellar surfaces. Indeed, we expect magnetic field strengths up to several Gauss. Consequently, tidally driven dynamos should be considered as a (complementary) dynamo mechanism, possibly operating in radiative MS and PMS stars hosting orbital companions. In particular, tidally driven dynamos may explain the observed magnetism of tidally deformed and rapidly rotating Vega-like stars.

  14. Tidal Energy Research

    Energy Technology Data Exchange (ETDEWEB)

    Stelzenmuller, Nickolas [Univ of Washington; Aliseda, Alberto [Univ of Washington; Palodichuk, Michael [Univ of Washington; Polagye, Brian [Univ of Washington; Thomson, James [Univ of Washington; Chime, Arshiya [Univ of Washington; Malte, Philip [Univ of washington

    2014-03-31

    This technical report contains results on the following topics: 1) Testing and analysis of sub-scale hydro-kinetic turbines in a flume, including the design and fabrication of the instrumented turbines. 2) Field measurements and analysis of the tidal energy resource and at a site in northern Puget Sound, that is being examined for turbine installation. 3) Conceptual design and performance analysis of hydro-kinetic turbines operating at high blockage ratio, for use for power generation and flow control in open channel flows.

  15. Brown adipocyte function

    DEFF Research Database (Denmark)

    Winther, Sally

    . The first part of this thesis explores this by identifying and investigating two novel kinase regulators of brown adipocyte function. Study 1 demonstrates that spleen tyrosine kinase is a hitherto undescribed regulator of brown adipocyte differentiation and activation. Study 2 identifies glycogen synthase...

  16. Sedimentary structures of tidal flats

    Indian Academy of Sciences (India)

    Sedimentary structures of some coastal tropical tidal flats of the east coast of India, and inner estuarine tidal point bars located at 30 to 50 kilometers inland from the coast, have been extensively studied under varying seasonal conditions. The results reveal that physical features such as flaser bedding, herringbone ...

  17. Effects of Portabella mushrooms on collagen-induced arthritis, inflammatory cytokines, and body composition in dilute brown non-agouti (DBA1 mice

    Directory of Open Access Journals (Sweden)

    Stanley A. Lightfoot

    2011-09-01

    Full Text Available Background:Exotic mushrooms have long been used in Asia for treatment and/or prevention of chronic diseases due to their immunomodulatory properties. However, the health benefits of portabella mushrooms (PM (brown Agaricus bisporous, on collagen-induced arthritis (CIA and associated complications, (i.e. loss of lean mass, increased fat mass and inflammatory cytokines, have not been previously investigated.Methods:We investigated CIA pathogenesis, body composition and plasma levels of IL- 6, TNF-α and sICAM1 in DBA1 female mice fed either the AIN76 diet or the same diet fortified with 5% lyophilized PM (n=19-20/group. Ten mice/group were immunized with 100 μg bovine collagen type II on day 42 of the protocol, followed by 50 μg lipopolysaccharides on day 62, and euthanized on day 73-74. Cytokines were measured by ELISA.Results:Compared to baseline diet, PM had: no protective effect from CIA since all collagen-immunized mice developed severe edema, bone erosion, and mononuclear cell infiltration in paws. In mice with and those without CIA, feeding a PM-fortified diet resulted in higher percent of body fat than feeding the baseline diet (p<0.05. After CIA induction, PM provided the followingFunctional Foods in Health and Disease 2011; 9:279-296beneficial effects: (a a smaller reduction in lean mass and absolute thymus weight; (b a higher fat mass loss; and (c lower plasma TNF-α levels (p <0.05. PM-fortification did not alter plasma IL-6 and sICAM1 regardless of CIA status; but it increased in vitro IL-6 secretion by mitogen-treated spleen cells.Conclusion:Our data suggest that PM may reduce plasma TNF-α, attenuate lean mass loss and thymus atrophy associated with arthritis, and protect spleen cell function assessed by IL-6 secretion. However, PM-fortification did not attenuate overall CIA pathogenesis which may be due to lack of effect on plasma IL-6. Decreased TNF-α without alterations in IL-6 may reduce the risk of other conditions

  18. Brown Fat AKT2 Is a Cold-Induced Kinase that Stimulates ChREBP-Mediated De Novo Lipogenesis to Optimize Fuel Storage and Thermogenesis

    DEFF Research Database (Denmark)

    Sanchez-Gurmaches, Joan; Tang, Yuefeng; Jespersen, Naja Zenius

    2018-01-01

    Brown adipose tissue (BAT) is a therapeutic target for metabolic diseases; thus, understanding its metabolic circuitry is clinically important. Many studies of BAT compare rodents mildly cold to those severely cold. Here, we compared BAT remodeling between thermoneutral and mild-cold-adapted mice...

  19. Tidal energy in France

    International Nuclear Information System (INIS)

    Lemperiere, F.

    2010-01-01

    The author first discusses the potential theoretical production of tidal energy in the world and more particularly in France, and compares this potential production with that of hydroelectric energy. He discusses the existence of potentially interesting sites in France in terms of sizing and exploitation modes. He describes the main associated works for turbines and sea walls, impacts on the environment, on the economy and on employment. He discusses the production possibilities and their cost, and the issue of energy storage. He indicates sites which could be built before 2025: Saint-Brieuc, Portbail-Coutainville or Granville, Mers or Cayeux, Penly or Saint-Valery en Caux. For each of this site, the author describes the project implantation, gives an gross assessment of the construction cost, and therefore of the kWh cost

  20. Fucoidans from brown seaweeds

    DEFF Research Database (Denmark)

    Ale, Marcel Tutor; Meyer, Anne S.

    2013-01-01

    -proliferative effects on cancer cells. Recent work has revealed distinct structural features of fucoidans obtained from different brown seaweed sources. Fucoidans are classically obtained from brown seaweeds by multi-step, hot acid extraction, but the structural and compositional traits, and possibly the bioactivity......Fucoidan or fucoidans cover a family of sulfated fucose-rich polysaccharides, built of a backbone of L-fucose units, and characteristically found in brown seaweeds. Fucoidans have potential therapeutic properties, including anti-inflammatory and anti-coagulant activities, as well as anti...

  1. Dynamical and photometric models of star formation in tidal tails

    International Nuclear Information System (INIS)

    Wallin, J.F.

    1990-01-01

    An investigation into the causes of star formation in tidal tails has been conducted using a restricted three-body dynamical model in conjunction with a broadband photometric evolutionary code. Test particles are initially placed in circular orbits around a softened point mass and then perturbed by a companion passing in a parabotic orbit. During the passage, the density evolution of the galaxy is examined both in regions within the disk and in selected comoving regions in the tidal features. Even without the inclusion of self-gravity and hydrodynamics, regions of compression form inside the disk, along the tidal tail, and in the tidal bridge causing local density increases of up to 500 percent. By assuming that the density changes relate to the star-formation rate via a Schmidt (1959) law, limits on the density changes needed to make detectable changes in the colors are calculated. A spiral galaxy population is synthesized and the effects of modest changes in the star-formation rate are explored using a broadband photometric evolutionary code. Density changes similar to those found in the dynamical models will cause detectable changes in the colors of a stellar population. From these models, it is determined that the blue colors and knotty features observed in the tidal features of some galaxies result from increased rates of star formation induced by tidally produced density increases. Limitations of this model are discussed along with photometric evolutionary models based on the density evolution in the tails. 52 refs

  2. Tidal pumping facilitates dissimilatory nitrate reduction in intertidal marshes

    Science.gov (United States)

    Zheng, Yanling; Hou, Lijun; Liu, Min; Liu, Zhanfei; Li, Xiaofei; Lin, Xianbiao; Yin, Guoyu; Gao, Juan; Yu, Chendi; Wang, Rong; Jiang, Xiaofen

    2016-01-01

    Intertidal marshes are alternately exposed and submerged due to periodic ebb and flood tides. The tidal cycle is important in controlling the biogeochemical processes of these ecosystems. Intertidal sediments are important hotspots of dissimilatory nitrate reduction and interacting nitrogen cycling microorganisms, but the effect of tides on dissimilatory nitrate reduction, including denitrification, anaerobic ammonium oxidation and dissimilatory nitrate reduction to ammonium, remains unexplored in these habitats. Here, we use isotope-tracing and molecular approaches simultaneously to show that both nitrate-reduction activities and associated functional bacterial abundances are enhanced at the sediment-tidal water interface and at the tide-induced groundwater fluctuating layer. This pattern suggests that tidal pumping may sustain dissimilatory nitrate reduction in intertidal zones. The tidal effect is supported further by nutrient profiles, fluctuations in nitrogen components over flood-ebb tidal cycles, and tidal simulation experiments. This study demonstrates the importance of tides in regulating the dynamics of dissimilatory nitrate-reducing pathways and thus provides new insights into the biogeochemical cycles of nitrogen and other elements in intertidal marshes. PMID:26883983

  3. Tidal energy site - Tidal energy site mammal/bird survey

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A vessel-based line visual transect survey was conducted for birds and marine mammals near the proposed Snohomish County PUD Admiralty Inlet tidal energy site...

  4. Brown Recluse Spider

    Science.gov (United States)

    ... to a group of spiders commonly known as violin spiders or fiddlebacks. The characteristic fiddle-shaped pattern ... 4-19.1mm) • Color: Golden brown • A dark violin/fiddle shape (see top photo) is located on ...

  5. Understanding Brown Dwarf Variability

    Science.gov (United States)

    Marley, Mark S.

    2013-01-01

    Surveys of brown dwarf variability continue to find that roughly half of all brown dwarfs are variable. While variability is observed amongst all types of brown dwarfs, amplitudes are typically greatest for L-T transition objects. In my talk I will discuss the possible physical mechanisms that are responsible for the observed variability. I will particularly focus on comparing and contrasting the effects of changes in atmospheric thermal profile and cloud opacity. The two different mechanisms will produce different variability signatures and I will discuss the extent to which the current datasets constrain both mechanisms. By combining constraints from studies of variability with existing spectral and photometric datasets we can begin to construct and test self-consistent models of brown dwarf atmospheres. These models not only aid in the interpretation of existing objects but also inform studies of directly imaged giant planets.

  6. CHALLENGES IN FORMING PLANETS BY GRAVITATIONAL INSTABILITY: DISK IRRADIATION AND CLUMP MIGRATION, ACCRETION, AND TIDAL DESTRUCTION

    International Nuclear Information System (INIS)

    Zhu Zhaohuan; Hartmann, Lee; Nelson, Richard P.; Gammie, Charles F.

    2012-01-01

    We present two-dimensional hydrodynamic simulations of self-gravitating protostellar disks subject to axisymmetric, continuing mass loading from an infalling envelope and irradiation from the central star to explore the growth of gravitational instability (GI) and disk fragmentation. We assume that the disk is built gradually and smoothly by the infall, resulting in good numerical convergence. We confirm that for disks around solar-mass stars, infall at high rates at radii beyond ∼50 AU leads to disk fragmentation. At lower infall rates, however, irradiation suppresses fragmentation. We find that, once formed, the fragments or clumps migrate inward on typical type I timescales of ∼2 × 10 3 yr initially, but with a stochastic component superimposed due to their interaction with the GI-induced spiral arms. Migration begins to deviate from the type I timescale when the clump becomes more massive than the local disk mass, and/or when the clump begins to form a gap in the disk. As they migrate, clumps accrete from the disk at a rate between 10 –3 and 10 –1 M J yr –1 , consistent with analytic estimates that assume a 1-2 Hill radii cross section. The eventual fates of these clumps, however, diverge depending on the migration speed: 3 out of 13 clumps in our simulations become massive enough (brown dwarf mass range) to open gaps in the disk and essentially stop migrating; 4 out of 13 are tidally destroyed during inward migration; and 6 out of 13 migrate across the inner boundary of the simulated disks. A simple analytic model for clump evolution explains the different fates of the clumps and reveals some limitations of two-dimensional simulations. Overall, our results indicate that fast migration, accretion, and tidal destruction of the clumps pose challenges to the scenario of giant planet formation by GI in situ, although we cannot address whether or not remnant solid cores can survive after tidal stripping. The models where the massive clumps are not

  7. On luminescence bleaching of tidal channel sediments

    DEFF Research Database (Denmark)

    Fruergaard, Mikkel; Pejrup, Morten; Murray, Andrew S.

    2015-01-01

    We investigate the processes responsible for bleaching of the quartz OSL signal from tidal channel sediment. Tidal dynamics are expected to play an important role for complete bleaching of tidal sediments. However, no studies have examined the amount of reworking occurring in tidal channels...... and on tidal flats due to the mixing caused by currents and waves. We apply bed level data to evaluate the amount of vertical sediment reworking in modern tidal channels and at a tidal flat. Cycles of deposition and erosion are measured with a bed level sensor, and the results show that gross sedimentation...... was several times higher than net sedimentation. We propose that tidal channel sediment is bleached either on the tidal flat before it is transported to the tidal channels and incorporated in channel-fill successions or, alternatively, on the shallow intertidal part of the channel banks. Based...

  8. Tidal Creek Sentinel Habitat Database

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Ecological Research, Assessment and Prediction's Tidal Creeks: Sentinel Habitat Database was developed to support the National Oceanic and Atmospheric...

  9. Simple Tidal Prism Models Revisited

    Science.gov (United States)

    Luketina, D.

    1998-01-01

    Simple tidal prism models for well-mixed estuaries have been in use for some time and are discussed in most text books on estuaries. The appeal of this model is its simplicity. However, there are several flaws in the logic behind the model. These flaws are pointed out and a more theoretically correct simple tidal prism model is derived. In doing so, it is made clear which effects can, in theory, be neglected and which can not.

  10. Spirulina maxima Extract Reduces Obesity through Suppression of Adipogenesis and Activation of Browning in 3T3-L1 Cells and High-Fat Diet-Induced Obese Mice.

    Science.gov (United States)

    Seo, Young-Jin; Kim, Kui-Jin; Choi, Jia; Koh, Eun-Jeong; Lee, Boo-Yong

    2018-06-01

    Obesity predisposes animals towards the metabolic syndrome and diseases such as type 2 diabetes, atherosclerosis, and cardiovascular disease. Spirulina maxima is a microalga with anti-oxidant, anti-cancer, and neuroprotective activities, but the anti-obesity effect of Spirulina maxima 70% ethanol extract (SM70EE) has not yet been fully established. We investigated the effect of SM70EE on adipogenesis, lipogenesis, and browning using in vitro and in vivo obesity models. SM70EE treatment reduced lipid droplet accumulation by the oil red O staining method and downregulated the adipogenic proteins C/EBPα, PPARγ, and aP2, and the lipogenic proteins SREBP1, ACC, FAS, LPAATβ, Lipin1, and DGAT1 by western blot analysis. In addition, the index components of SM70EE, chlorophyll a, and C-phycocyanin, reduced adipogenesis and lipogenesis protein levels in 3T3-L1 and C3H10T1/2 cells. High-fat diet (HFD)-fed mice administered with SM70EE demonstrated smaller adipose depots and lower blood lipid concentrations than control HFD-fed mice. The lower body mass gain in treated SM70EE-administrated mice was associated with lower protein expression of adipogenesis factors and higher expression of AMPKα-induced adipose browning proteins PRDM16, PGC1α, and UCP1. SM70EE administration ameliorates obesity, likely by reducing adipogenesis and activating the thermogenic program, in 3T3-L1 cells and HFD-induced obese mice.

  11. Policy for tidal energy

    Energy Technology Data Exchange (ETDEWEB)

    Shaw, T L

    1977-01-01

    The potential of tidal energy for the United Kingdom should be reassessed, it is argued, and some of its advantages are cited. The technology for its development is available and proven; experience suggests that the capital works will have an indefinite life, with only the turbine blades needing to be replaced occasionally. It is a source of water power, and can be regulated to generate when required, on a flexible basis and only by day if so desired; this compares favorably with the relatively unpredictable nature of the other sources. It can be made to complement directly, and so to improve the performance of the coal and nuclear sources at a scale readily possible from a proportionately small installed capacity. The fuel is free. Present indications unquestionably suggest that it will be timely to reassess this source as part of the present energy review, so that its potential may be realized when needed after 1990. It is especially significant that the environmental effects of the necessary works appear to be comparatively small whereas the industrial and social rewards, so far not financially quantified, could be appreciable. The disadvantages that have been expressed are cited, but the author counters the attack on them. (MCW)

  12. Tidal interaction of galaxies

    International Nuclear Information System (INIS)

    Kozlov, N.N.; Syunyaev, R.A.; Ehneev, T.M.

    1974-01-01

    One of the hypotheses explaining the occurrence of anomalous details in interacting galaxies has been investigated. Pairs of galaxies with 'tails' oppositely directed or neighbouring galaxies with cofferdams 'bridges', as if connecting the galaxies, are called interacting galaxies. The hypothesis connects the origin of cofferdams and 'tails' of interacting galaxies with tidal effects ; the action of power gravitational forces in the intergalactic space. A source of such forces may be neighbouring stellar systems or invisible bodies, for instance, 'dead' quasars after a gravitational collapse. The effect of large masses of matter on the galaxy evolution has been investigated in the Institute of Applied Mathematics of the Academy of Sciences of the USSSR in 1971-1972 by numerical simulation of the process on a digital computer with the subsequent data transmission on a display. Different versions of a massive body flight relative to a galaxy disk are considered. Photographs of a display screen at different moments of time are presented. As a result of mathematical simulation of galaxies gravitational interactions effects are discovered which resemble real structures in photographs of galaxies. It seems to be premature to state that namely these mechanisms cause the formation of 'tails' and cofferdams between galaxies. However, even now it is clear that the gravitational interaction strongly affects the dynamics of the stellar system evolution. Further studies should ascertain a true scale of this effect and its genuine role in galaxy evolution

  13. Fucose-Containing Sulfated Polysaccharides from Brown Seaweeds Inhibit Proliferation of Melanoma Cells and Induce Apoptosis by Activation of Caspase-3 in Vitro

    DEFF Research Database (Denmark)

    Ale, Marcel Tutor; Maruyama, Hiroko; Tamauchi, Hidekazu

    2011-01-01

    Fucose-containing sulfated polysaccharides (FCSPs) extracted from seaweeds, especially brown macro-algae, are known to possess essential bioactive properties, notably growth inhibitory effects on tumor cells. In this work, we conducted a series of in vitro studies to examine the influence of FCSPs...... of the FCSPs, particularly the presence of sulfated galactofucans (notably in S. henslowianum) and sulfated fucans (notably in F. vesiculosus). This study thus indicates that unfractionated FCSPs may exert bioactive effects on skin cancer cells via induction of apoptosis through cascades of reactions...

  14. The economics of tidal energy

    International Nuclear Information System (INIS)

    Denny, Eleanor

    2009-01-01

    Concern over global climate change has led policy makers to accept the importance of reducing greenhouse gas emissions. This in turn has led to a large growth in clean renewable generation for electricity production. Much emphasis has been on wind generation as it is among the most advanced forms of renewable generation, however, its variable and relatively unpredictable nature result in increased challenges for electricity system operators. Tidal generation on the other hand is almost perfectly forecastable and as such may be a viable alternative to wind generation. This paper calculates the break-even capital cost for tidal generation on a real electricity system. An electricity market model is used to determine the impact of tidal generation on the operating schedules of the conventional units on the system and on the resulting cycling costs, emissions and fuel savings. It is found that for tidal generation to produce positive net benefits for the case study, the capital costs would have to be less than Euro 510,000 per MW installed which is currently an unrealistically low capital cost. Thus, it is concluded that tidal generation is not a viable option for the case system at the present time.

  15. Remnants of strong tidal interactions

    International Nuclear Information System (INIS)

    Mcglynn, T.A.

    1990-01-01

    This paper examines the properties of stellar systems that have recently undergone a strong tidal shock, i.e., a shock which removes a significant fraction of the particles in the system, and where the shocked system has a much smaller mass than the producer of the tidal field. N-body calculations of King models shocked in a variety of ways are performed, and the consequences of the shocks are investigated. The results confirm the prediction of Jaffe for shocked systems. Several models are also run where the tidal forces on the system are constant, simulating a circular orbit around a primary, and the development of tidal radii under these static conditions appears to be a mild process which does not dramatically affect material that is not stripped. The tidal radii are about twice as large as classical formulas would predict. Remnant density profiles are compared with a sample of elliptical galaxies, and the implications of the results for the development of stellar populations and galaxies are considered. 38 refs

  16. TIDAL LIMITS TO PLANETARY HABITABILITY

    International Nuclear Information System (INIS)

    Barnes, Rory; Jackson, Brian; Greenberg, Richard; Raymond, Sean N.

    2009-01-01

    The habitable zones (HZs) of main-sequence stars have traditionally been defined as the range of orbits that intercept the appropriate amount of stellar flux to permit surface water on a planet. Terrestrial exoplanets discovered to orbit M stars in these zones, which are close-in due to decreased stellar luminosity, may also undergo significant tidal heating. Tidal heating may span a wide range for terrestrial exoplanets and may significantly affect conditions near the surface. For example, if heating rates on an exoplanet are near or greater than that on Io (where tides drive volcanism that resurfaces the planet at least every 1 Myr) and produce similar surface conditions, then the development of life seems unlikely. On the other hand, if the tidal heating rate is less than the minimum to initiate plate tectonics, then CO 2 may not be recycled through subduction, leading to a runaway greenhouse that sterilizes the planet. These two cases represent potential boundaries to habitability and are presented along with the range of the traditional HZ for main-sequence, low-mass stars. We propose a revised HZ that incorporates both stellar insolation and tidal heating. We apply these criteria to GJ 581 d and find that it is in the traditional HZ, but its tidal heating alone may be insufficient for plate tectonics.

  17. Numerical analysis of stratification and destratification processes in a tidally energetic inlet with an ebb tidal delta

    NARCIS (Netherlands)

    Purkiani, K.; Becherer, J.; Flöser, G.; Gräwe, U.; Mohrholz, V.; Schuttelaars, H.M.; Burchard, H.

    2015-01-01

    Stratification and destratification processes in a tidally energetic, weakly stratified inlet in the Wadden Sea (south eastern North Sea) are investigated in this modeling study. Observations of current velocity and vertical density structure show strain-induced periodic stratification for the

  18. Tune Your Brown Clustering, Please

    DEFF Research Database (Denmark)

    Derczynski, Leon; Chester, Sean; Bøgh, Kenneth Sejdenfaden

    2015-01-01

    Brown clustering, an unsupervised hierarchical clustering technique based on ngram mutual information, has proven useful in many NLP applications. However, most uses of Brown clustering employ the same default configuration; the appropriateness of this configuration has gone predominantly...

  19. Natural Inhibitors of Maillard Browning

    Science.gov (United States)

    2013-12-01

    BREAD COLORING CHEESE SPREAD CHEMICAL REACTIONS FLAVOR OXIDATION DAIRY PRODUCTS...nutritional intake, and decrease waste due to non-consumption of sensory degraded ration components. 1.1 Maillard Browning Maillard browning, also

  20. The Effects of Florfenicol on the Values of Serum Tumor Necrosis Factor-α and Other Biochemical Markers in Lipopolysaccharide-Induced Endotoxemia in Brown Trout

    Directory of Open Access Journals (Sweden)

    Ayse Er

    2014-01-01

    Full Text Available The aim of the present study was to determine the effects of florfenicol on the expected changes in sTNF-α, damage markers of the liver and kidney, and the lipid metabolism parameters in endotoxemic brown trout. Ninety-six brown trout were included in this study. After six of the fish were reserved as the control group, the remaining 90 fish were divided equally into 3 groups as follows: LPS (2 mg/kg, IP, LPS (2 mg/kg, IP + florfenicol (40 mg/kg, IM, and florfenicol (40 mg/kg, IM. Blood samples were obtained from the tail of the fish at 1.5, 3, 6, 10, and 24 hours. The levels of sTNF-α were determined by ELISA and biochemical markers were evaluated with an autoanalyzer. A significant increase was observed in the values of sTNF-α in the LPS and LPS + florfenicol groups (P<0.05. Significant increases were found in the kidney and liver damage determinants in the LPS and LPS + florfenicol groups (P<0.05. Irregular changes in the lipid metabolism parameters were observed in all the subgroups. In conclusion, florfenicol does not affect the increases of sTNF-α caused by LPS and does not prevent liver or kidney damage; at least, it can be said that florfenicol does not have any evident positive effects on the acute endotoxemia of fish.

  1. Real-time images of tidal recruitment using lung ultrasound.

    Science.gov (United States)

    Tusman, Gerardo; Acosta, Cecilia M; Nicola, Marco; Esperatti, Mariano; Bohm, Stephan H; Suarez-Sipmann, Fernando

    2015-12-01

    Ventilator-induced lung injury is a form of mechanical damage leading to a pulmonary inflammatory response related to the use of mechanical ventilation enhanced by the presence of atelectasis. One proposed mechanism of this injury is the repetitive opening and closing of collapsed alveoli and small airways within these atelectatic areas-a phenomenon called tidal recruitment. The presence of tidal recruitment is difficult to detect, even with high-resolution images of the lungs like CT scan. The purpose of this article is to give evidence of tidal recruitment by lung ultrasound. A standard lung ultrasound inspection detected lung zones of atelectasis in mechanically ventilated patients. With a linear probe placed in the intercostal oblique position. We observed tidal recruitment within atelectasis as an improvement in aeration at the end of inspiration followed by the re-collapse at the end of expiration. This mechanism disappeared after the performance of a lung recruitment maneuver. Lung ultrasound was helpful in detecting the presence of atelectasis and tidal recruitment and in confirming their resolution after a lung recruitment maneuver.

  2. Tidal variations of earth rotation

    Science.gov (United States)

    Yoder, C. F.; Williams, J. G.; Parke, M. E.

    1981-01-01

    The periodic variations of the earths' rotation resulting from the tidal deformation of the earth by the sun and moon were rederived including terms with amplitudes of 0.002 millisec and greater. The series applies to the mantle, crust, and oceans which rotate together for characteristic tidal periods; the scaling parameter is the ratio of the fraction of the Love number producing tidal variations in the moment of inertia of the coupled mantle and oceans (k) to the dimensionless polar moment of inertia of the coupled moments (C). The lunar laser ranging data shows that k/C at monthly and fortnightly frequencies equals 0.99 + or - 0.15 and 0.99 + or - 0.20 as compared to the theoretical value of 0.94 + or - 0.04.

  3. Browns Ferry fire

    International Nuclear Information System (INIS)

    Harkleroad, J.R.

    1983-01-01

    A synopsis of the March 22, 1975 fire at Browns Ferry Nuclear Plant is discussed. Emphasis is placed on events prior to and during the fire. How the fire started, fire fighting activities, fire and smoke development, and restoration activities are discussed

  4. Estrogenic effects of phytoestrogens in brown trout (Salmo trutta)

    DEFF Research Database (Denmark)

    Nielsen, Louise Marie; Holbech, Henrik; Bjerregaard, Poul

    2010-01-01

    , the potential effect of the waterborne phytoestrogens on endemic fish species is largely unknown. In the present investigation, the estrogenic effect of biochanin A was tested in brown trout through water exposure experiments. Juvenile brown trout of both sexes were exposed to different concentrations...... of biochanin A. In a ten day exposure experiments, NOEC and LOEC for plasma vitellogenin induction in brown trout were found to be 0.8µg biochanin A/L and 1.2µg biochanin A/L, respectively. A six hour pulse experiment resulted in NOEC and LOEC for induction of plasma vitellogenin in brown trout of 48µg...... biochanin A/L and 186µg biochanin A/L, respectively. Investigations of the ability of genistein to induce vitellogenin synthesis in brown trout are ongoing....

  5. The distribution and tapping tidal energy

    Directory of Open Access Journals (Sweden)

    Zygmunt Kowalik

    2004-09-01

    Full Text Available Tidal power along tidal shores has been used for centuries to run small tidal mills. Generating electricity by tapping tidal power proved to be very successful only in the last century through the tidal power plant constructed in 1967 in La Rance, France. This used a large barrier to generate the sea level head necessary for driving turbines. Construction of such plants evolved very slowly because of prohibitive costs and concerns about the environmental impact. Developments in the construction of small, efficient and inexpensive underwater turbines admit the possibility of small scale operations that will use local tidal currents to bring electricity to remote locations. Since the generation of such electricity is concerned with the tidal energy in local water bodies, it is important to understand the site-specific energy balance, i.e., the energy flowing in through open boundaries, and the energy generated and dissipated within the local domain. The question is how to tap the tidal energy while keeping possible changes in the present tidal regimes to a minimum. The older approach of constructing barrages may still be quite useful in some locations. The basics of such tidal power plants constructed in a small bay are analyzed in order to understand the principal parameter for tidal plant evaluation, i.e., the power produced.     The new approach is to place turbines - devices similar to windmills - in the pathway of tidal currents. Theoretically, the amount of power available by such turbines for electricity generation is proportional to the water density and velocity cubed of the tidal flow. The naturally dissipated tidal power due to bottom friction forces is also proportional to the cube of the velocity. Because of this similarity, the exploitation of tidal energy can be directed to reinvesting the naturally dissipated power into tidal power for the generation of electricity. This approach to tidal power exploitation is better tuned

  6. Turning the tide : tidal power in the UK

    OpenAIRE

    Sustainable Development Commission

    2007-01-01

    Contents: Turning the tide : tidal power in the UK -- Executive summary -- Tidal power in the UK : research report 1 : UK tidal resource assessment -- Tidal power in the UK : research report 2 : tidal technologies overview -- Tidal power in the UK : research report 3 : Severn barrage proposals -- Tidal power in the UK : research report 4 : Severn non-barrage options -- Tidal power in the UK : research report 5 : UK case studies. Summarised in the Welsh language version of the executive ...

  7. Facies architecture of heterolithic tidal deposits : The Holocene Holland Tidal Basin

    NARCIS (Netherlands)

    Donselaar, M.E.; Geel, C.R.

    2007-01-01

    The size, shape and spatial position of lithofacies types (or facies architecture) in a tidal estuarine basin are complex and therefore difficult to model. The tidal currents in the basin concentrate sand-sized sediment in a branching pattern of tidal channels and fringing tidal flats. Away from the

  8. Geometry and dynamics of a tidally deformed black hole

    International Nuclear Information System (INIS)

    Poisson, Eric; Vlasov, Igor

    2010-01-01

    The metric of a nonrotating black hole deformed by a tidal interaction is calculated and expressed as an expansion in the strength of the tidal coupling. The expansion parameter is the inverse length scale R -1 , where R is the radius of curvature of the external spacetime in which the black hole moves. The expansion begins at order R -2 , and it is carried out through order R -4 . The metric is parametrized by a number of tidal multipole moments, which specify the black hole's tidal environment. The tidal moments are freely-specifiable functions of time that are related to the Weyl tensor of the external spacetime. At order R -2 the metric involves the tidal quadrupole moments E ab and B ab . At order R -3 it involves the time derivative of the quadrupole moments and the tidal octupole moments E abc and B abc . At order R -4 the metric involves the second time derivative of the quadrupole moments, the first time derivative of the octupole moments, the tidal hexadecapole moments E abcd and B abcd , and bilinear combinations of the quadrupole moments. The metric is presented in a light-cone coordinate system that possesses a clear geometrical meaning: The advanced-time coordinate v is constant on past light cones that converge toward the black hole; the angles θ and φ are constant on the null generators of each light cone; and the radial coordinate r is an affine parameter on each generator, which decreases as the light cones converge toward the black hole. The coordinates are well-behaved on the black-hole horizon, and they are adjusted so that the coordinate description of the horizon is the same as in the Schwarzschild geometry: r=2M+O(R -5 ). At the order of accuracy maintained in this work, the horizon is a stationary null hypersurface foliated by apparent horizons; it is an isolated horizon in the sense of Ashtekar and Krishnan. As an application of our results we examine the induced geometry and dynamics of the horizon, and calculate the rate at which the

  9. Tidal flow separation at protruding beach nourishments

    NARCIS (Netherlands)

    Radermacher, M.; de Schipper, M.A.; Swinkels, Cilia M.; MacMahan, Jamie; Reniers, A.J.H.M.

    2016-01-01

    In recent years, the application of large-scale beach nourishments has been discussed, with the Sand Motor in the Netherlands as the first real-world example. Such protruding beach nourishments have an impact on tidal currents, potentially leading to tidal flow separation and the generation of tidal

  10. Tidal energy - a technology review

    International Nuclear Information System (INIS)

    Price, R.

    1991-01-01

    The tides are caused by gravitational attraction of the sun and the moon acting upon the world's oceans. This creates a clean renewable form of energy which can in principle be tapped for the benefit of mankind. This paper reviews the status of tidal energy, including the magnitude of the resource, the technology which is available for its extraction, the economics, possible environmental effects and non-technical barriers to its implementation. Although the total energy flux of the tides is large, at about 2 TW, in practice only a very small fraction of this total potential can be utilised in the foreseeable future. This is because the energy is spread diffusely over a wide area, requiring large and expensive plant for its collection, and is often available remote from centres of consumption. The best mechanism for exploiting tidal energy is to employ estuarine barrages at suitable sites with high tidal ranges. The technology is relatively mature and components are commercially available now. Also, many of the best sites for implementation have been identified. However, the pace and extent of commercial exploitation of tidal energy is likely to be significantly influenced, both by the treatment of environmental costs of competing fossil fuels, and by the availability of construction capital at modest real interest rates. The largest projects could require the involvement of national governments if they are to succeed. (author) 8 figs., 2 tabs., 19 refs

  11. Properties of active tidal bedforms

    DEFF Research Database (Denmark)

    Winter, Christian; Lefebvre, Alice; Becker, Marius

    2016-01-01

    Bedforms of various shapes and sizes are ubiquitous in tidal channels, inlets and estuaries. They constitute a form roughness which has a large scale effect on the hydrodynamics and sediment transport of coastal environments. It has been shown that this form roughness can be expressed in terms...

  12. Influence of high carbohydrate versus high fat diet in ozone induced pulmonary injury and systemic metabolic impairment in a Brown Norway (BN) rat model of healthy aging

    Science.gov (United States)

    Rationale: Air pollution has been recently linked to the increased prevalence of metabolic syndrome. It has been postulated that dietary risk factors might exacerbate air pollution-induced metabolic impairment. We have recently reported that ozone exposure induces acute systemic ...

  13. Tidal constraints on the interior of Venus

    Science.gov (United States)

    Dumoulin, C.; Tobie, G.; Verhoeven, O.; Rosenblatt, P.; Rambaux, N.

    2017-12-01

    As a prospective study for a future exploration of Venus, we compute the tidal response of Venus' interior assuming various mantle compositions and temperature profiles representative of different scenarios of Venus' formation and evolution. The mantle density and seismic velocities are modeled from thermodynamical equilibria of mantle minerals and used to predict the moment of inertia, Love numbers, and tide-induced phase lag characterizing the signature of the internal structure in the gravity field. The viscoelasticity of the mantle is parameterized using an Andrade rheology. From the models considered here, the moment of inertia lies in the range of 0.327 to 0.342, corresponding to a core radius of 2900 to 3450 km. Viscoelasticity of the mantle strongly increases the potential Love number relative to previously published elastic models. Due to the anelasticity effects, we show that the possibility of a completely solid metal core inside Venus cannot be ruled out based on the available estimate of k2 from the Magellan mission (Konopliv and Yoder, 1996). A Love number k2 lower than 0.27 would indicate the presence of a fully solid iron core, while for larger values, solutions with an entirely or partially liquid core are possible. Precise determination of the Love numbers, k2 and h2, together with an estimate of the tidal phase lag, are required to determine the state and size of the core, as well as the composition and viscosity of the mantle.

  14. Brown dwarf accretion: Nonconventional star formation over very long timescales

    Directory of Open Access Journals (Sweden)

    Ćirković Milan M.

    2005-01-01

    Full Text Available We investigate the process of accretion of interstellar gas by the Galactic population of brown dwarfs over very long timescales typical for physical eschatology. In particular, we use the classical Hoyle-Lyttleton-Bondi accretion model to investigate the rate at which brown dwarfs collect enough additional mass to become red dwarfs, accretion-induced changes in the mass function of the low- mass objects, and the corresponding accretion heating of brown dwarfs. In addition, we show how we can make the definition of the final mass function for stellar objects more precise.

  15. Dynamic and photometric evolutionary models of tidal tails and ripples

    International Nuclear Information System (INIS)

    Wallin, J.F.

    1989-01-01

    An investigation into the causes of star formation in tidal tails has been conducted using a restricted three-body dynamical model in conjunction with a broad-band photometric evolutionary code. In these models, regions of compression form inside the disk and along the tidal tail and tidal bridge. The effects these density changes have on the colors of the tidal features are examined with a broad-band photometric evolutionary code. A spiral galaxy population is synthesized and the effects of modest changes in the star formation rate are explored. Limits on the density changes needed to make detectable changes in the colors are calculated using a Schmidt (1959) law. These models suggest that the blue colors and knotty features observed in the tidal features of some galaxies result from increased rates of star formation induced by tidally produced density increases. Limitations of this model are discussed along with photometric evolutionary models based on the density evolution in the tails. The Lynds and Toomre (1976) interpretation of ring galaxies as the natural result of a nearly head-on collision between a disk galaxy and a companion galaxy has become widely accepted. Similarly, Quinn's (1984) interpretation of the shells in elliptical galaxies as the aftermath of the cannibalization of a low-mass companion has been quite successful in accounting for the observations. Restricted three-body calculations of high inclination, low impact parameter encounters demonstrate that the shell-like ripples observed in a number of disk galaxies can also be produced as collisional artifacts from internal oscillations much as in ring galaxies

  16. Oral administration of drugs with hypersensitivity potential induces germinal center hyperplasia in secondary lymphoid organ/tissue in Brown Norway rats, and this histological lesion is a promising candidate as a predictive biomarker for drug hypersensitivity occurrence in humans

    International Nuclear Information System (INIS)

    Tamura, Akitoshi; Miyawaki, Izuru; Yamada, Toru; Kimura, Juki; Funabashi, Hitoshi

    2013-01-01

    It is important to evaluate the potential of drug hypersensitivity as well as other adverse effects during the preclinical stage of the drug development process, but validated methods are not available yet. In the present study we examined whether it would be possible to develop a new predictive model of drug hypersensitivity using Brown Norway (BN) rats. As representative drugs with hypersensitivity potential in humans, phenytoin (PHT), carbamazepine (CBZ), amoxicillin (AMX), and sulfamethoxazole (SMX) were orally administered to BN rats for 28 days to investigate their effects on these animals by examinations including observation of clinical signs, hematology, determination of serum IgE levels, histology, and flow cytometric analysis. Skin rashes were not observed in any animals treated with these drugs. Increases in the number of circulating inflammatory cells and serum IgE level did not necessarily occur in the animals treated with these drugs. However, histological examination revealed that germinal center hyperplasia was commonly induced in secondary lymphoid organs/tissues in the animals treated with these drugs. In cytometric analysis, changes in proportions of lymphocyte subsets were noted in the spleen of the animals treated with PHT or CBZ during the early period of administration. The results indicated that the potential of drug hypersensitivity was identified in BN rat by performing histological examination of secondary lymphoid organs/tissues. Data obtained herein suggested that drugs with hypersensitivity potential in humans gained immune reactivity in BN rat, and the germinal center hyperplasia induced by administration of these drugs may serve as a predictive biomarker for drug hypersensitivity occurrence. - Highlights: • We tested Brown Norway rats as a candidate model for predicting drug hypersensitivity. • The allergic drugs did not induce skin rash, whereas D-penicillamine did so in the rats. • Some of allergic drugs increased

  17. Oral administration of drugs with hypersensitivity potential induces germinal center hyperplasia in secondary lymphoid organ/tissue in Brown Norway rats, and this histological lesion is a promising candidate as a predictive biomarker for drug hypersensitivity occurrence in humans

    Energy Technology Data Exchange (ETDEWEB)

    Tamura, Akitoshi, E-mail: akitoshi-tamura@ds-pharma.co.jp; Miyawaki, Izuru; Yamada, Toru; Kimura, Juki; Funabashi, Hitoshi

    2013-08-15

    It is important to evaluate the potential of drug hypersensitivity as well as other adverse effects during the preclinical stage of the drug development process, but validated methods are not available yet. In the present study we examined whether it would be possible to develop a new predictive model of drug hypersensitivity using Brown Norway (BN) rats. As representative drugs with hypersensitivity potential in humans, phenytoin (PHT), carbamazepine (CBZ), amoxicillin (AMX), and sulfamethoxazole (SMX) were orally administered to BN rats for 28 days to investigate their effects on these animals by examinations including observation of clinical signs, hematology, determination of serum IgE levels, histology, and flow cytometric analysis. Skin rashes were not observed in any animals treated with these drugs. Increases in the number of circulating inflammatory cells and serum IgE level did not necessarily occur in the animals treated with these drugs. However, histological examination revealed that germinal center hyperplasia was commonly induced in secondary lymphoid organs/tissues in the animals treated with these drugs. In cytometric analysis, changes in proportions of lymphocyte subsets were noted in the spleen of the animals treated with PHT or CBZ during the early period of administration. The results indicated that the potential of drug hypersensitivity was identified in BN rat by performing histological examination of secondary lymphoid organs/tissues. Data obtained herein suggested that drugs with hypersensitivity potential in humans gained immune reactivity in BN rat, and the germinal center hyperplasia induced by administration of these drugs may serve as a predictive biomarker for drug hypersensitivity occurrence. - Highlights: • We tested Brown Norway rats as a candidate model for predicting drug hypersensitivity. • The allergic drugs did not induce skin rash, whereas D-penicillamine did so in the rats. • Some of allergic drugs increased

  18. Maine Tidal Power Initiative: Environmental Impact Protocols For Tidal Power

    Energy Technology Data Exchange (ETDEWEB)

    Peterson, Michael Leroy [Univ. of Maine, Orono, ME; Zydlewski, Gayle Barbin [Univ. of Maine, Orono, ME; Xue, Huijie [Univ. of Maine, Orono, ME; Johnson, Teresa R. [Univ. of Maine, Orono, ME

    2014-02-02

    The Maine Tidal Power Initiative (MTPI), an interdisciplinary group of engineers, biologists, oceanographers, and social scientists, has been conducting research to evaluate tidal energy resources and better understand the potential effects and impacts of marine hydro-kinetic (MHK) development on the environment and local community. Project efforts include: 1) resource assessment, 2) development of initial device design parameters using scale model tests, 3) baseline environmental studies and monitoring, and 4) human and community responses. This work included in-situ measurement of the environmental and social response to the pre-commercial Turbine Generator Unit (TGU®) developed by Ocean Renewable Power Company (ORPC) as well as considering the path forward for smaller community scale projects.

  19. Effects of pre-germinated brown rice treatment high-fat diet-induced metabolic syndrome in C57BL/6J mice.

    Science.gov (United States)

    Yen, Hsueh-Wei; Lin, Hui-Li; Hao, Chi-Long; Chen, Fu-Chih; Chen, Chun-Yun; Chen, Jia-Hao; Shen, Kuo-Ping

    2017-05-01

    To investigate using pre-germinated brown rice (PGBR) to treat metabolic syndrome, we fed one group of mice standard-regular-diet (SRD) for 20 weeks and another group of mice high-fat-diet (HFD) for 16 weeks. We subdivided them into HFD group and HFD + PGBR group whose dietary carbohydrate was replaced with PGBR for 4 weeks. The HFD group gained more weight, had higher blood pressure, heart rate, blood glucose and lipids, liver levels of TG, feces TG and bile acid, lower adipose levels of adipocytokine, lower skeletal muscle IR, IRS-1, IRS-2, PI3 K, Akt/PKB, GLUT-1, GLUT-4, GCK and PPAR-γ; higher liver SREBP-1, SCD-1, FAS, HMGCR, LDLR, CYP7α1 and PPAR-α, and higher adipose SREBP-1, SCD-1, FAS, and lower adipose PPAR-α and adiponectin. The HFD + PGBR group had clearly improved blood pressure, biochemical parameters and above proteins expressions. PGBR successful treatment of metabolic syndrome was achieved through improvements in glucose and lipid synthesis and metabolism.

  20. Testosterone-induced modulation of peroxisomal morphology and peroxisome-related gene expression in brown trout (Salmo trutta f. fario) primary hepatocytes.

    Science.gov (United States)

    Lopes, Célia; Malhão, Fernanda; Guimarães, Cláudia; Pinheiro, Ivone; Gonçalves, José F; Castro, L Filipe C; Rocha, Eduardo; Madureira, Tânia V

    2017-12-01

    Disruption of androgenic signaling has been linked to possible cross-modulation with other hormone-mediated pathways. Therefore, our objective was to explore effects caused by testosterone - T (1, 10 and 50μM) in peroxisomal signaling of brown trout hepatocytes. To study the underlying paths involved, several co-exposure conditions were tested, with flutamide - F (anti-androgen) and ICI 182,780 - ICI (anti-estrogen). Molecular and morphological approaches were both evaluated. Peroxisome proliferator-activated receptor alpha (PPARα), catalase and urate oxidase were the selected targets for gene expression analysis. The vitellogenin A gene was also included as a biomarker of estrogenicity. Peroxisome relative volumes were estimated by immunofluorescence, and transmission electron microscopy was used for qualitative morphological control. The single exposures of T caused a significant down-regulation of urate oxidase (10 and 50μM) and a general up-regulation of vitellogenin. A significant reduction of peroxisome relative volumes and smaller peroxisome profiles were observed at 50μM. Co-administration of T and ICI reversed the morphological modifications and vitellogenin levels. The simultaneous exposure of T and F caused a significant and concentration-dependent diminishing in vitellogenin expression. Together, the findings suggest that in the tested model, T acted via both androgen and estrogen receptors to shape the peroxisomal related targets. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Efficacy of a novel topical combination of fipronil, amitraz and (S)-methoprene for treatment and control of induced infestations of brown dog ticks (Rhipicephalus sanguineus) on dogs.

    Science.gov (United States)

    Hunter, James S; Baggott, Derek; Everett, William R; Fourie, Josephus J; Cramer, Luiz G; Yoon, Stephen S; Collidor, Nadia; Mallouk, Yasmina; Lee, Lorne; Blair, Jeffrey; Prullage, Joseph B

    2011-07-15

    Four laboratory studies were conducted to demonstrate that a single topical dose of a novel spot-on combination containing fipronil, amitraz and (S)-methoprene (CERTIFECT™, Merial Limited, GA, USA) is efficacious against the brown dog tick, Rhipicephalus sanguineus. In each study, 6-8 male and 6-8 female purpose-bred, laboratory mongrels, terrier cross or Beagles were randomly assigned to one of two study groups (treated and untreated), based on pre-treatment parasite counts. Starting on the day before treatment, each dog was infested weekly with 50 ticks. Ticks were thumb counted at various time points after treatment and weekly infestations starting as early as 6h and continued at 12, 18 and 24h depending on the study. Ticks were removed and counted at 48 h after treatment and weekly infestations. CERTIFECT provided rapid and excellent control of pre-existing and newly acquired infestations of R. sanguineus with efficacy as high as 93% within the first 12h after a single topical treatment. Excellent control (>96%) of R. sanguineus as early as 18 h, following post treatment infestations was maintained for at least 35 days. Copyright © 2011 Elsevier B.V. All rights reserved.

  2. Mercury dynamics in a San Francisco estuary tidal wetland: assessing dynamics using in situ measurements

    Science.gov (United States)

    Bergamaschi, Brian A.; Fleck, Jacob A.; Downing, Bryan D.; Boss, Emmanuel; Pellerin, Brian A.; Ganju, Neil K.; Schoellhamer, David H.; Byington, Amy A.; Heim, Wesley A.; Stephenson, Mark; Fujii, Roger

    2012-01-01

    We used high-resolution in situ measurements of turbidity and fluorescent dissolved organic matter (FDOM) to quantitatively estimate the tidally driven exchange of mercury (Hg) between the waters of the San Francisco estuary and Browns Island, a tidal wetland. Turbidity and FDOM—representative of particle-associated and filter-passing Hg, respectively—together predicted 94 % of the observed variability in measured total mercury concentration in unfiltered water samples (UTHg) collected during a single tidal cycle in spring, fall, and winter, 2005–2006. Continuous in situ turbidity and FDOM data spanning at least a full spring-neap period were used to generate UTHg concentration time series using this relationship, and then combined with water discharge measurements to calculate Hg fluxes in each season. Wetlands are generally considered to be sinks for sediment and associated mercury. However, during the three periods of monitoring, Browns Island wetland did not appreciably accumulate Hg. Instead, gradual tidally driven export of UTHg from the wetland offset the large episodic on-island fluxes associated with high wind events. Exports were highest during large spring tides, when ebbing waters relatively enriched in FDOM, dissolved organic carbon (DOC), and filter-passing mercury drained from the marsh into the open waters of the estuary. On-island flux of UTHg, which was largely particle-associated, was highest during strong winds coincident with flood tides. Our results demonstrate that processes driving UTHg fluxes in tidal wetlands encompass both the dissolved and particulate phases and multiple timescales, necessitating longer term monitoring to adequately quantify fluxes.

  3. Dynamical modeling of tidal streams

    International Nuclear Information System (INIS)

    Bovy, Jo

    2014-01-01

    I present a new framework for modeling the dynamics of tidal streams. The framework consists of simple models for the initial action-angle distribution of tidal debris, which can be straightforwardly evolved forward in time. Taking advantage of the essentially one-dimensional nature of tidal streams, the transformation to position-velocity coordinates can be linearized and interpolated near a small number of points along the stream, thus allowing for efficient computations of a stream's properties in observable quantities. I illustrate how to calculate the stream's average location (its 'track') in different coordinate systems, how to quickly estimate the dispersion around its track, and how to draw mock stream data. As a generative model, this framework allows one to compute the full probability distribution function and marginalize over or condition it on certain phase-space dimensions as well as convolve it with observational uncertainties. This will be instrumental in proper data analysis of stream data. In addition to providing a computationally efficient practical tool for modeling the dynamics of tidal streams, the action-angle nature of the framework helps elucidate how the observed width of the stream relates to the velocity dispersion or mass of the progenitor, and how the progenitors of 'orphan' streams could be located. The practical usefulness of the proposed framework crucially depends on the ability to calculate action-angle variables for any orbit in any gravitational potential. A novel method for calculating actions, frequencies, and angles in any static potential using a single orbit integration is described in the Appendix.

  4. Tidally Induced Bars of Galaxies in Clusters

    Czech Academy of Sciences Publication Activity Database

    Lokas, E.; Ebrová, Ivana; del Pino, A.; Sybilska, A.; Athanassoula, E.; Semczuk, M.; Gajda, G.; Fouquet, S.

    2016-01-01

    Roč. 286, č. 6 (2016), 227/1-227/13 ISSN 0004-637X Institutional support: RVO:67985815 Keywords : galaxies * clusters * evolution Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 5.533, year: 2016

  5. Prospects for Fundy tidal power

    International Nuclear Information System (INIS)

    Clark, R.H.

    1997-01-01

    The Bay of Fundy in Canada probably possesses the most favourable conditions in the world for the exploitation of tidal energy. The results of the comprehensive investigations carried out during the past quarter-century are reviewed together with operating and environmental aspects of the modest (20 MW) Annapolis Tidal Power Station, commissioned in 1984, the primary purpose of which was to evaluate the operation of a large (7.6 m) diameter Straflo turbine unit under low heads. The results of the operating and maintenance experience for the Annapolis Station are reviewed as well as the results of the environmental/ecological studies that have been on-going in the Annapolis Basin. The tidal power investigations have shown that a 1400 MW development at the mouth of the Cumberland Basin, at the head of the bay of Fundy, is technically and economically feasible and that its output would probably be competitive with fossil-fired plants, particularly if a 'green' accounting technique were applied to such energy sources. The importance of timing, if the exploitation of this non-polluting, renewable and completely predicable source is to be used to meet the future electrical energy needs of the maritime provinces, is discussed. (author)

  6. Acid Hydrolysis of Wheat Gluten Induces Formation of New Epitopes but Does Not Enhance Sensitizing Capacity by the Oral Route: A Study in “Gluten Free” Brown Norway Rats

    DEFF Research Database (Denmark)

    Kroghsbo, Stine; Andersen, Nanna Birch; Rasmussen, Tina Frid

    2014-01-01

    the sensitizing capacity of gluten proteins per se when altered by acid or enzymatic hydrolysis relative to unmodified gluten in rats naïve to gluten. Methods High IgE-responder Brown Norway (BN) rats bred on a gluten-free diet were sensitized without the use of adjuvant to three different gluten products...... (unmodified, acid hydrolyzed and enzymatic hydrolyzed). Rats were sensitized by intraperitoneal (i.p.) immunization three times with 200 µg gluten protein/rat or by oral dosing for 35 days with 0.2, 2 or 20 mg gluten protein/rat/day. Sera were analyzed for specific IgG and IgE and IgG-binding capacity...... by ELISA. IgE functionality was measured by rat basophilic leukemia (RBL) assay. Results Regardless of the route of dosing, all products had sensitizing capacity. When sensitized i.p., all three gluten products induced a strong IgG1 response in all animals. Acid hydrolyzed gluten induced the highest level...

  7. ARE TIDAL EFFECTS RESPONSIBLE FOR EXOPLANETARY SPIN–ORBIT ALIGNMENT?

    Energy Technology Data Exchange (ETDEWEB)

    Li, Gongjie [Harvard-Smithsonian Center for Astrophysics, The Institute for Theory and Computation, 60 Garden Street, Cambridge, MA 02138 (United States); Winn, Joshua N., E-mail: gli@cfa.harvard.edu [Department of Physics, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States)

    2016-02-10

    The obliquities of planet-hosting stars are clues about the formation of planetary systems. Previous observations led to the hypothesis that for close-in giant planets, spin–orbit alignment is enforced by tidal interactions. Here, we examine two problems with this hypothesis. First, Mazeh and coworkers recently used a new technique—based on the amplitude of starspot-induced photometric variability—to conclude that spin–orbit alignment is common even for relatively long-period planets, which would not be expected if tides were responsible. We re-examine the data and find a statistically significant correlation between photometric variability and planetary orbital period that is qualitatively consistent with tidal interactions. However it is still difficult to explain quantitatively, as it would require tides to be effective for periods as long as tens of days. Second, Rogers and Lin argued against a particular theory for tidal re-alignment by showing that initially retrograde systems would fail to be re-aligned, in contradiction with the observed prevalence of prograde systems. We investigate a simple model that overcomes this problem by taking into account the dissipation of inertial waves and the equilibrium tide, as well as magnetic braking. We identify a region of parameter space where re-alignment can be achieved, but it only works for close-in giant planets, and requires some fine tuning. Thus, while we find both problems to be more nuanced than they first appeared, the tidal model still has serious shortcomings.

  8. TIDAL FRICTION AND TIDAL LAGGING. APPLICABILITY LIMITATIONS OF A POPULAR FORMULA FOR THE TIDAL TORQUE

    International Nuclear Information System (INIS)

    Efroimsky, Michael; Makarov, Valeri V.

    2013-01-01

    Tidal torques play a key role in rotational dynamics of celestial bodies. They govern these bodies' tidal despinning and also participate in the subtle process of entrapment of these bodies into spin-orbit resonances. This makes tidal torques directly relevant to the studies of habitability of planets and their moons. Our work begins with an explanation of how friction and lagging should be built into the theory of bodily tides. Although much of this material can be found in various publications, a short but self-consistent summary on the topic has been lacking in the hitherto literature, and we are filling the gap. After these preparations, we address a popular concise formula for the tidal torque, which is often used in the literature, for planets or stars. We explain why the derivation of this expression, offered in the paper by Goldreich and in the books by Kaula (Equation (4.5.29)) and Murray and Dermott (Equation (4.159)), implicitly sets the time lag to be frequency independent. Accordingly, the ensuing expression for the torque can be applied only to bodies having a very special (and very hypothetical) rheology which makes the time lag frequency independent, i.e., the same for all Fourier modes in the spectrum of tide. This expression for the torque should not be used for bodies of other rheologies. Specifically, the expression cannot be combined with an extra assertion of the geometric lag being constant, because at finite eccentricities the said assumption is incompatible with the constant-time-lag condition.

  9. TIDAL FRICTION AND TIDAL LAGGING. APPLICABILITY LIMITATIONS OF A POPULAR FORMULA FOR THE TIDAL TORQUE

    Energy Technology Data Exchange (ETDEWEB)

    Efroimsky, Michael; Makarov, Valeri V., E-mail: michael.efroimsky@usno.navy.mil, E-mail: vvm@usno.navy.mil [US Naval Observatory, Washington, DC 20392 (United States)

    2013-02-10

    Tidal torques play a key role in rotational dynamics of celestial bodies. They govern these bodies' tidal despinning and also participate in the subtle process of entrapment of these bodies into spin-orbit resonances. This makes tidal torques directly relevant to the studies of habitability of planets and their moons. Our work begins with an explanation of how friction and lagging should be built into the theory of bodily tides. Although much of this material can be found in various publications, a short but self-consistent summary on the topic has been lacking in the hitherto literature, and we are filling the gap. After these preparations, we address a popular concise formula for the tidal torque, which is often used in the literature, for planets or stars. We explain why the derivation of this expression, offered in the paper by Goldreich and in the books by Kaula (Equation (4.5.29)) and Murray and Dermott (Equation (4.159)), implicitly sets the time lag to be frequency independent. Accordingly, the ensuing expression for the torque can be applied only to bodies having a very special (and very hypothetical) rheology which makes the time lag frequency independent, i.e., the same for all Fourier modes in the spectrum of tide. This expression for the torque should not be used for bodies of other rheologies. Specifically, the expression cannot be combined with an extra assertion of the geometric lag being constant, because at finite eccentricities the said assumption is incompatible with the constant-time-lag condition.

  10. TIDAL NOVAE IN COMPACT BINARY WHITE DWARFS

    International Nuclear Information System (INIS)

    Fuller, Jim; Lai Dong

    2012-01-01

    Compact binary white dwarfs (WDs) undergoing orbital decay due to gravitational radiation can experience significant tidal heating prior to merger. In these WDs, the dominant tidal effect involves the excitation of outgoing gravity waves in the inner stellar envelope and the dissipation of these waves in the outer envelope. As the binary orbit decays, the WDs are synchronized from outside in (with the envelope synchronized first, followed by the core). We examine the deposition of tidal heat in the envelope of a carbon-oxygen WD and study how such tidal heating affects the structure and evolution of the WD. We show that significant tidal heating can occur in the star's degenerate hydrogen layer. This layer heats up faster than it cools, triggering runaway nuclear fusion. Such 'tidal novae' may occur in all WD binaries containing a CO WD, at orbital periods between 5 minutes and 20 minutes, and precede the final merger by 10 5 -10 6 years.

  11. Seasonal variability of tidal and non-tidal currents off Beypore, SW coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    DineshKumar, P.K.; Srinivas, K.; AnilKumar, N.

    and summer monsoon seasons of year 2000. Information on tidal signals contained in the currents were extracted using harmonic analysis - Least Squares Method and non-tidal component were analyzed using the Chi sub(o) filter. The study established...

  12. Interactions Between Wetlands and Tidal Inlets

    National Research Council Canada - National Science Library

    Sanchez, Alejandro

    2008-01-01

    This Coastal and Hydraulics Engineering Technical Note (CHETN) presents numerical simulations investigating how the loss of wetlands in estuaries modifies tidal processes in inlet navigation channels...

  13. Formation of double galaxies by tidal capture

    International Nuclear Information System (INIS)

    Alladin, S.M.; Potdar, A.; Sastry, K.S.

    1975-01-01

    The conditions under which double galaxies may be formed by tidal capture are considered. Estimates for the increase in the internal energy of colliding galaxies due to tidal effects are used to determine the magnitudes Vsub(cap) and Vsub(dis) of the maximum relative velocities at infinite separation required for tidal capture and tidal disruption respectively. A double galaxy will be formed by tidal capture without tidal disruption of a component if Vsub(cap)>Vsub(i) and Vsub(cap)>Vsub(dis) where Vsub(i) is the initial relative speed of the two galaxies at infinite separation. If the two galaxies are of the same dimension, formulation of double galaxies by tidal capture is possible in a close collision either if the two galaxies do not differ much in mass and density distribution or if the more massive galaxy is less centrally concentrated than the other. If it is assumed as statistics suggest, that the mass of a galaxy is proportional to the square of its radius, it follows that the probability of the formation of double galaxies by tidal capture increases with the increase in mass of the galaxies and tidal distribution does not occur in a single collision for any distance of closest approach of the two galaxies. (Auth.)

  14. Coastal tomographic mapping of nonlinear tidal currents and residual currents

    Science.gov (United States)

    Zhu, Ze-Nan; Zhu, Xiao-Hua; Guo, Xinyu

    2017-07-01

    Depth-averaged current data, which were obtained by coastal acoustic tomography (CAT) July 12-13, 2009 in Zhitouyang Bay on the western side of the East China Sea, are used to estimate the semidiurnal tidal current (M2) as well as its first two overtide currents (M4 and M6). Spatial mean amplitude ratios M2:M4:M6 in the bay are 1.00:0.15:0.11. The shallow-water equations are used to analyze the generation mechanisms of M4 and M6. In the deep area, where water depths are larger than 60 m, M4 velocity amplitudes measured by CAT agree well with those predicted by the advection terms in the shallow water equations, indicating that M4 in the deep area is predominantly generated by the advection terms. M6 measured by CAT and M6 predicted by the nonlinear quadratic bottom friction terms agree well in the area where water depths are less than 20 m, indicating that friction mechanisms are predominant for generating M6 in the shallow area. In addition, dynamic analysis of the residual currents using the tidally averaged momentum equation shows that spatial mean values of the horizontal pressure gradient due to residual sea level and of the advection of residual currents together contribute about 75% of the spatial mean values of the advection by the tidal currents, indicating that residual currents in this bay are induced mainly by the nonlinear effects of tidal currents. This is the first ever nonlinear tidal current study by CAT.

  15. Acid Hydrolysis of Wheat Gluten Induces Formation of New Epitopes but Does Not Enhance Sensitizing Capacity by the Oral Route: A Study in “Gluten Free” Brown Norway Rats

    Science.gov (United States)

    Kroghsbo, Stine; Andersen, Nanna B.; Rasmussen, Tina F.; Madsen, Charlotte B.

    2014-01-01

    Background Acid hydrolyzed wheat proteins (HWPs) are used in the food and cosmetic industry as emulsifiers. Cases of severe food allergic reactions caused by HWPs have been reported. Recent data suggest that these reactions are caused by HWPs produced by acid hydrolysis. Objectives To examine the sensitizing capacity of gluten proteins per se when altered by acid or enzymatic hydrolysis relative to unmodified gluten in rats naïve to gluten. Methods High IgE-responder Brown Norway (BN) rats bred on a gluten-free diet were sensitized without the use of adjuvant to three different gluten products (unmodified, acid hydrolyzed and enzymatic hydrolyzed). Rats were sensitized by intraperitoneal (i.p.) immunization three times with 200 µg gluten protein/rat or by oral dosing for 35 days with 0.2, 2 or 20 mg gluten protein/rat/day. Sera were analyzed for specific IgG and IgE and IgG-binding capacity by ELISA. IgE functionality was measured by rat basophilic leukemia (RBL) assay. Results Regardless of the route of dosing, all products had sensitizing capacity. When sensitized i.p., all three gluten products induced a strong IgG1 response in all animals. Acid hydrolyzed gluten induced the highest level of specific IgE but with a low functionality. Orally all three gluten products induced specific IgG1 and IgE but with different dose-response relations. Sensitizing rats i.p. or orally with unmodified or enzymatic hydrolyzed gluten induced specific IgG1 responses with similar binding capacity which was different from that of acid hydrolyzed gluten indicating that acid hydrolysis of gluten proteins induces formation of ‘new’ epitopes. Conclusions In rats not tolerant to gluten acid hydrolysis of gluten enhances the sensitizing capacity by the i.p. but not by the oral route. In addition, acid hydrolysis induces formation of new epitopes. This is in contrast to the enzymatic hydrolyzed gluten having an epitope pattern similar to unmodified gluten. PMID:25207551

  16. Tidal Evolution of Asteroidal Binaries. Ruled by Viscosity. Ignorant of Rigidity.

    Science.gov (United States)

    Efroimsky, Michael

    2015-10-01

    This is a pilot paper serving as a launching pad for study of orbital and spin evolution of binary asteroids. The rate of tidal evolution of asteroidal binaries is defined by the dynamical Love numbers kl divided by quality factors Q. Common in the literature is the (oftentimes illegitimate) approximation of the dynamical Love numbers with their static counterparts. Since the static Love numbers are, approximately, proportional to the inverse rigidity, this renders a popular fallacy that the tidal evolution rate is determined by the product of the rigidity by the quality factor: {k}l/Q\\propto 1/(μ Q). In reality, the dynamical Love numbers depend on the tidal frequency and all rheological parameters of the tidally perturbed body (not just rigidity). We demonstrate that in asteroidal binaries the rigidity of their components plays virtually no role in tidal friction and tidal lagging, and thereby has almost no influence on the intensity of tidal interactions (tidal torques, tidal dissipation, tidally induced changes of the orbit). A key quantity that overwhelmingly determines the tidal evolution is a product of the effective viscosity η by the tidal frequency χ . The functional form of the torque’s dependence on this product depends on who wins in the competition between viscosity and self-gravitation. Hence a quantitative criterion, to distinguish between two regimes. For higher values of η χ , we get {k}l/Q\\propto 1/(η χ ), {while} for lower values we obtain {k}l/Q\\propto η χ . Our study rests on an assumption that asteroids can be treated as Maxwell bodies. Applicable to rigid rocks at low frequencies, this approximation is used here also for rubble piles, due to the lack of a better model. In the future, as we learn more about mechanics of granular mixtures in a weak gravity field, we may have to amend the tidal theory with other rheological parameters, ones that do not show up in the description of viscoelastic bodies. This line of study provides

  17. Atmospheres of Brown Dwarfs

    Science.gov (United States)

    Wang, Ruoyan; Seay, Christopher

    2018-01-01

    We construct a grid of brown dwarf model atmospheres spanning a wide range of atmospheric metallicity (0.3x ≤ met ≤ 100x), C/O ratios (0.25x ≤ C/O ≤ 2.5x), and cloud properties, encompassing atmospheres of effective temperatures 200 ≤ Teff ≤ 2400 K and gravities 2.5 ≤ log g ≤ 5.5. We produce the expected temperature-pressure profiles and emergent spectra from an atmosphere in radiative-convective equilibrium. We can then compare our predicted spectra to observations and retrieval results to aid in their predictions and influence future missions and telescopic observations. In our poster we briefly describe our modeling methodology and present our progress on model grid construction, spanning solar and subsolar C/O and metallicity.

  18. Perinatal exposure to germinated brown rice and its gamma amino-butyric acid-rich extract prevents high fat diet-induced insulin resistance in first generation rat offspring

    Directory of Open Access Journals (Sweden)

    Hadiza Altine Adamu

    2016-02-01

    Full Text Available Background: Evidence suggests perinatal environments influence the risk of developing insulin resistance. Objective: The present study was aimed at determining the effects of intrauterine exposure to germinated brown rice (GBR and GBR-derived gamma (γ aminobutyric acid (GABA extract on epigenetically mediated high fat diet–induced insulin resistance. Design: Pregnant Sprague Dawley rats were fed high-fat diet (HFD, HFD+GBR, or HFD+GABA throughout pregnancy until 4 weeks postdelivery. The pups were weighed weekly and maintained on normal pellet until 8 weeks postdelivery. After sacrifice, biochemical markers of obesity and insulin resistance including oral glucose tolerance test, adiponectin, leptin, and retinol binding protein-4 (RBP4 were measured. Hepatic gene expression changes and the global methylation and histone acetylation levels were also evaluated. Results: Detailed analyses revealed that mothers given GBR and GABA extract, and their offspring had increased adiponectin levels and reduced insulin, homeostasis model assessment of insulin resistance, leptin, oxidative stress, and RBP4 levels, while their hepatic mRNA levels of GLUT2 and IPF1 were increased. Furthermore, GBR and GABA extract lowered global DNA methylation levels and modulated H3 and H4 acetylation levels. Conclusions: These results showed that intrauterine exposure to GBR-influenced metabolic outcomes in offspring of rats with underlying epigenetic changes and transcriptional implications that led to improved glucose homeostasis.

  19. Protective effects against H2O2-induced damage by enzymatic hydrolysates of an edible brown seaweed, sea tangle (Laminaria japonica).

    Science.gov (United States)

    Park, Pyo-Jam; Kim, Eun-Kyung; Lee, Seung-Jae; Park, Sun-Young; Kang, Dong-Soo; Jung, Bok-Mi; Kim, Kui-Shik; Je, Jae-Young; Ahn, Chang-Bum

    2009-02-01

    Enzymatic hydrolysates of Laminaria japonica were evaluated for antioxidative activities using hydroxyl radical scavenging activity and protective effects against H(2)O(2)-induced DNA and cell damage. In addition, activities of antioxidative enzymes, including catalase, glutathione peroxidase, and glutathione S-transferase, of the enzymatic hydrolysates from L. japonica were also estimated. L. japonica was first enzymatically hydrolyzed by seven carbohydrases (Dextrozyme, AMG, Promozyme, Maltogenase, Termamyl, Viscozyme, and Celluclast [all from Novo Co., Novozyme Nordisk, Bagsvaerd, Denmark]) and five proteinases (Flavourzyme, Neutrase, Protamex, Alcalase [all from Novo Co.], and pancreatic trypsin). The hydroxyl radical scavenging activities of Promozyme and pancreatic trypsin hydrolysates from L. japonica were the highest as compared to those of the other carbohydrases and proteinases, and their 50% inhibitory concentration values were 1.67 and 317.49 mug/mL, respectively. The pancreatic trypsin hydrolysates of L. japonica exerted a protective effect on H(2)O(2)-induced DNA damage. We also evaluated the protective effect on hydroxyl radical-induced oxidative damage in PC12 cells via propidium iodide staining using a flow cytometer. The AMG and pancreatic trypsin hydrolysates of L. japonica dose-dependently protected PC12 cells against cell death caused by hydroxyl radical-induced oxidative damage. Additionally, we analyzed the activity of antioxidative enzymes such as catalase, glutathione peroxidase, and the phase II biotransformation enzyme glutathione S-transferase in L. japonica-treated cells. The activity of all antioxidative enzymes was higher in L. japonica-treated cells compared with the nontreated cells. These results indicate that enzymatic hydrolysates of L. japonica possess antioxidative activity.

  20. Modulation of Tidal Channel Signatures on SAR Images Over Gyeonggi Bay in Relation to Environmental Factors

    Directory of Open Access Journals (Sweden)

    Tae-Sung Kim

    2018-04-01

    Full Text Available In this study, variations of radar backscatter features of the tidal channel in Gyeonggi Bay in the Eastern Yellow Sea were investigated using spaceborne synthetic aperture radar (SAR images. Consistent quasi-linear bright features appeared on the SAR images. Examining the detailed local bathymetry chart, we found that the features were co-located with the major axis of the tidal channel in the region. It was also shown that modulation of the radar backscatter features changed according to the environmental conditions at the time of imaging. For the statistical analysis, the bathymetric features over the tidal channel were extracted by an objective method. In terms of shape, the extracted features had higher variability in width than in length. The analysis of the variation in intensity with the coinciding bathymetric distribution confirmed that the quasi-linear bright features on the SAR images are fundamentally imprinted due to the surface current convergence and divergence caused by the bathymetry-induced tidal current variation. Furthermore, the contribution of environmental factors to the intensity modulation was quantitatively analyzed. A comparison of the variation in normalized radar cross section (NRCS with tidal current showed a positive correlation only with the perpendicular component of tidal current (r= 0.47. This implies that the modulation in intensity of the tidal channel signatures is mainly affected by the interaction with cross-current flow. On the other hand, the modulation of the NRCS over the tidal channel tended to be degraded as wind speed increased (r= −0.65. Considering the environmental circumstances in the study area, it can be inferred that the imaging capability of SAR for the detection of tidal channel signatures mainly relies on wind speed.

  1. State of the art in protection of erosion-corrosion on vertical axis tidal current turbine

    Science.gov (United States)

    Musabikha, Siti; Utama, I. Ketut Aria Pria; Mukhtasor

    2018-05-01

    Vertical axis tidal current turbine is main part of ocean energy devices which converts the tidal current energy into electricity. Its development is arising too due to increased interest research topic concerning climate change mitigation. Due to its rotating movement, it will be induced mechanical forces, such as shear stress and/or particle impact. Because of its natural operations, vertical axis turbine is also being exposed to harsh and corroding marine environment itself. In order to secure the vertical tidal turbine devices from mechanical wear and corrosion effects which is lead to a material loss, an appropriate erosion-corrosion protection needs to be defined. Its protection actionscan be derived such as design factors, material selections, inhibitors usage, cathodic protections, and coatings. This paper aims to analyze protection method which is necessary to control erosion-corrosion phenomenon that appears to the vertical axis tidal current turbine.

  2. 3-D modelling the electric field due to ocean tidal flow and comparison with observations

    DEFF Research Database (Denmark)

    Kuvshinov, A.; Junge, A.; Utada, H.

    2006-01-01

    The tidal motion of the ocean water through the ambient magnetic field, generates secondary electric field. This motionally induced electric field can be detected in the sea or inland and has a potential for electrical soundings of the Earth. A first goal of the paper is to gain an understanding...... that in some coastal regions the amplitudes of the electric field can reach 100 mV/km and 10 mV/km for M2 and O1 tides respectively. The changes of lithosphere resistance produce detectable changes in the tidal electric signals. We show that our predictions are in a good agreement with observations....... of the global distribution of the electric signal due to tidal ocean flow. We simulate the electric signals for two tidal constituents - lunar semidiurnal (M2) and diurnal (O1) tides. We assume a realistic Earth's conductivity model with a surface thin shell and 1-D mantle underneath. Simulations demonstrate...

  3. In brown adipocytes, adrenergically induced β{sub 1}-/β{sub 3}-(G{sub s})-, α{sub 2}-(G{sub i})- and α{sub 1}-(G{sub q})-signalling to Erk1/2 activation is not mediated via EGF receptor transactivation

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yanling; Fälting, Johanna M.; Mattsson, Charlotte L.; Holmström, Therése E.; Nedergaard, Jan, E-mail: jan@metabol.su.se

    2013-10-15

    Brown adipose tissue is unusual in that the neurotransmitter norepinephrine influences cell destiny in ways generally associated with effects of classical growth factors: regulation of cell proliferation, of apoptosis, and progression of differentiation. The norepinephrine effects are mediated through G-protein-coupled receptors; further mediation of such stimulation to e.g. Erk1/2 activation is in cell biology in general accepted to occur through transactivation of the EGF receptor (by external or internal pathways). We have examined here the significance of such transactivation in brown adipocytes. Stimulation of mature brown adipocytes with cirazoline (α{sub 1}-adrenoceptor coupled via G{sub q}), clonidine (α{sub 2} via G{sub i}) or CL316243 (β{sub 3} via G{sub s}) or via β{sub 1}-receptors significantly activated Erk1/2. Pretreatment with the EGF receptor kinase inhibitor AG1478 had, remarkably, no significant effect on Erk1/2 activation induced by any of these adrenergic agonists (although it fully abolished EGF-induced Erk1/2 activation), demonstrating absence of EGF receptor-mediated transactivation. Results with brown preadipocytes (cells in more proliferative states) were not qualitatively different. Joint stimulation of all adrenoceptors with norepinephrine did not result in synergism on Erk1/2 activation. AG1478 action on EGF-stimulated Erk1/2 phosphorylation showed a sharp concentration–response relationship (IC{sub 50} 0.3 µM); a minor apparent effect of AG1478 on norepinephrine-stimulated Erk1/2 phosphorylation showed nonspecific kinetics, implying caution in interpretation of partial effects of AG1478 as reported in other systems. Transactivation of the EGF receptor is clearly not a universal prerequisite for coupling of G-protein coupled receptors to Erk1/2 signalling cascades. - Highlights: • In brown adipocytes, norepinephrine regulates proliferation, apoptosis, differentiation. • EGF receptor transactivation is supposed to mediate GPCR-induced

  4. Tidal mixing in Dahej creek waters

    Digital Repository Service at National Institute of Oceanography (India)

    Swamy, G.N.; Sarma, R.V.

    Mixing characteristics of a tidal inlet near Dahej at the mouth of Narmada River, Gujarat, India are examined in terms of tides, currents and bathymetry. The dilution potential of the Dahej Creek waters during a tidal march for a given rate...

  5. TIDALLY HEATED TERRESTRIAL EXOPLANETS: VISCOELASTIC RESPONSE MODELS

    International Nuclear Information System (INIS)

    Henning, Wade G.; O'Connell, Richard J.; Sasselov, Dimitar D.

    2009-01-01

    Tidal friction in exoplanet systems, driven by orbits that allow for durable nonzero eccentricities at short heliocentric periods, can generate internal heating far in excess of the conditions observed in our own solar system. Secular perturbations or a notional 2:1 resonance between a hot Earth and hot Jupiter can be used as a baseline to consider the thermal evolution of convecting bodies subject to strong viscoelastic tidal heating. We compare results first from simple models using a fixed Quality factor and Love number, and then for three different viscoelastic rheologies: the Maxwell body, the Standard Anelastic Solid (SAS), and the Burgers body. The SAS and Burgers models are shown to alter the potential for extreme tidal heating by introducing the possibility of new equilibria and multiple response peaks. We find that tidal heating tends to exceed radionuclide heating at periods below 10-30 days, and exceed insolation only below 1-2 days. Extreme cases produce enough tidal heat to initiate global-scale partial melting, and an analysis of tidal limiting mechanisms such as advective cooling for earthlike planets is discussed. To explore long-term behaviors, we map equilibria points between convective heat loss and tidal heat input as functions of eccentricity. For the periods and magnitudes discussed, we show that tidal heating, if significant, is generally detrimental to the width of habitable zones.

  6. Relativistic theory of tidal Love numbers

    International Nuclear Information System (INIS)

    Binnington, Taylor; Poisson, Eric

    2009-01-01

    In Newtonian gravitational theory, a tidal Love number relates the mass multipole moment created by tidal forces on a spherical body to the applied tidal field. The Love number is dimensionless, and it encodes information about the body's internal structure. We present a relativistic theory of Love numbers, which applies to compact bodies with strong internal gravities; the theory extends and completes a recent work by Flanagan and Hinderer, which revealed that the tidal Love number of a neutron star can be measured by Earth-based gravitational-wave detectors. We consider a spherical body deformed by an external tidal field, and provide precise and meaningful definitions for electric-type and magnetic-type Love numbers; and these are computed for polytropic equations of state. The theory applies to black holes as well, and we find that the relativistic Love numbers of a nonrotating black hole are all zero.

  7. 7 CFR 29.3505 - Brown colors.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Brown colors. 29.3505 Section 29.3505 Agriculture... Type 95) § 29.3505 Brown colors. A group of colors ranging from a light brown to a dark brown. These colors vary from medium to low saturation and from medium to very low brillance. As used in these...

  8. 7 CFR 29.2504 - Brown colors.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Brown colors. 29.2504 Section 29.2504 Agriculture...-Cured Tobacco (u.s. Types 22, 23, and Foreign Type 96) § 29.2504 Brown colors. A group of colors ranging from a reddish brown to yellowish brown. These colors vary from low to medium saturation and from very...

  9. Tidal current and tidal energy changes imposed by a dynamic tidal power system in the Taiwan Strait, China

    Science.gov (United States)

    Dai, Peng; Zhang, Jisheng; Zheng, Jinhai

    2017-12-01

    The Taiwan Strait has recently been proposed as a promising site for dynamic tidal power systems because of its shallow depth and strong tides. Dynamic tidal power is a new concept for extracting tidal potential energy in which a coast-perpendicular dike is used to create water head and generate electricity via turbines inserted in the dike. Before starting such a project, the potential power output and hydrodynamic impacts of the dike must be assessed. In this study, a two-dimensional numerical model based on the Delft3D-FLOW module is established to simulate tides in China. A dike module is developed to account for turbine processes and estimate power output by integrating a special algorithm into the model. The domain decomposition technique is used to divide the computational zone into two subdomains with grid refinement near the dike. The hydrodynamic processes predicted by the model, both with and without the proposed construction, are examined in detail, including tidal currents and tidal energy flux. The predicted time-averaged power yields with various opening ratios are presented. The results show that time-averaged power yield peaks at an 8% opening ratio. For semidiurnal tides, the flow velocity increases in front of the head of the dike and decreases on either side. For diurnal tides, these changes are complicated by the oblique incidence of tidal currents with respect to the dike as well as by bathymetric features. The dike itself blocks the propagation of tidal energy flux.

  10. Channel Capture as a Response to Anthropogenic Modification of a Tidal Landscape: Ganges-Brahmaputra-Meghna Delta, Southwest Bangladesh

    Science.gov (United States)

    Wilson, C.; Bain, R. L.; Goodbred, S. L., Jr.; Hale, R. P.

    2017-12-01

    Studies of tidal channel dynamics frequently emphasize "morphologically short" spatial scales (i.e., settings in which the cross-system tidal propagation time is negligible) or idealized single-channel planforms. In contrast, tides in the Ganges-Brahmaputra-Meghna Delta (GBMD) propagate more than 100 kilometers inland from the coast through a network of interconnected tidal estuaries, producing complex hydrodynamic behavior that remains poorly understood. Intense anthropogenic modification of the GBMD landscape further complicates tidally-driven, natural delta surface maintenance. Analyzing this system is particularly urgent given the current trend of rising sea level and its associated impacts on coastal communities.We present results from an ongoing field investigation of tidal waveform interaction and mass exchange between the Pussur and Shibsa Rivers, two large macrotidal estuaries in the southwestern GBMD. In the 1960s, construction of earthen embankments ("polders") eliminated regular tidal inundation for a vast region of the tidal platform, shrinking the Shibsa and Pussur basins by an estimated 1000 km2 and 700 km2, respectively. Conservation of mass predicts that a reduction in tidal basin area will decrease peak flow velocities and induce channel siltation; indeed, 100 km2 of secondary channels at the distal end of the tidal range have partly or fully closed in recent decades. The Pussur is likewise rapidly shoaling, restricting navigational access along a major shipping route. However, discharge and bathymetric datasets indicate that the adjacent Shibsa conveys three to four times more water than the Pussur and is actively scouring its bed, contrary to its predicted response to polder construction. Our field measurements are consistent with an ongoing channel capture event in which the Shibsa floods and drains a progressively greater portion of the former Pussur basin, allowing the Shibsa to widen and deepen despite the regional trend of channel

  11. Is there evidence of adaptation to tidal flooding in saplings of baldcypress subjected to different salinity regimes?

    Science.gov (United States)

    Krauss, K.W.; Doyle, T.W.; Howard, R.J.

    2009-01-01

    Plant populations may adapt to environmental conditions over time by developing genetically based morphological or physiological characteristics. For tidal freshwater forested wetlands, we hypothesized that the conditions under which trees developed led to ecotypic difference in response of progeny to hydroperiod. Specifically, we looked for evidence of ecotypic adaptation for tidal flooding at different salinity regimes using growth and ecophysiological characteristics of two tidal and two non-tidal source collections of baldcypress (Taxodium distichum (L.) L.C. Rich) from the southeastern United States. Saplings were subjected to treatments of hydrology (permanent versus tidal flooding) and salinity (0 versus ???2 g l-1) for two and a half growing seasons in a greenhouse environment. Saplings from tidal sources maintained 21-41% lower overall growth and biomass accumulation than saplings from non-tidal sources, while saplings from non-tidal sources maintained 14-19% lower overall rates of net photosynthetic assimilation, leaf transpiration, and stomatal conductance than saplings from tidal sources. However, we found no evidence for growth or physiological enhancement of saplings from tidal sources to tide, or of saplings from non-tidal sources to no tide. All saplings growing under permanent flooding exhibited reduced growth and leaf gas exchange regardless of source, with little evidence for consistent salinity effects across hydroperiods. While we reject our original hypothesis, we suggest that adaptations of coastal baldcypress to broad (rather than narrow) environmental conditions may promote ecophysiological and growth enhancements under a range of global-change-induced stressors, perhaps reflecting a natural resilience to environmental change while precluding adaptations for specific flood regimes.

  12. Radurization of brown shrimps

    International Nuclear Information System (INIS)

    Ehlermann, D.; Muenzner, R.

    1976-01-01

    Brown shrimps (Crangon vulgaris) from the North sea coast were blanched on board, and irradiated with cobalt-60 gamma-rays at a minimum dose of 130 krad either before or after peeling. Other samples were irradiated before and after peeling. Control samples remained untreated or were preserved with benzoic acid. Irradiation before peeling did not result in a lasting improvement of keeping quality. However, irradiation of the peeled shrimp meat resulted in a reduction of the total bacterial load by up to 4 orders of magnitude. Shelf life until the initial microbial count was reached was 9 days for chemically treated samples, 18 days for samples irradiated after peeling, and 20 days for samples irradiated before and after peeling. Sensory evaluation and determination of volatile basic nitrogen gave similar results. The obtained diminution of the counts of staphylococci, enterococci and enterobacteriaceae reduces the hygienic hazard. Radurization of shrimp meat proved to be a satisfactory means of preservation. Introduction of the product into the market and best presentation and packaging require further investigations. (orig.) [de

  13. Atmospheric noise of a breaking tidal bore.

    Science.gov (United States)

    Chanson, Hubert

    2016-01-01

    A tidal bore is a surge of waters propagating upstream in an estuary as the tidal flow turns to rising and the flood tide propagates into a funnel-shaped system. Large tidal bores have a marked breaking roller. The sounds generated by breaking tidal bores were herein investigated in the field (Qiantang River) and in laboratory. The sound pressure record showed two dominant periods, with some similarity with an earlier study [Chanson (2009). J. Acoust. Soc. Am. 125(6), 3561-3568]. The two distinct phases were the incoming tidal bore when the sound amplitude increased with the approaching bore, and the passage of the tidal bore in front of the microphone when loud and powerful noises were heard. The dominant frequency ranged from 57 to 131 Hz in the Qiantang River bore. A comparison between laboratory and prototype tidal bores illustrated both common features and differences. The low pitch sound of the breaking bore had a dominant frequency close to the collective oscillations of bubble clouds, which could be modeled with a bubble cloud model using a transverse dimension of the bore roller. The findings suggest that this model might be over simplistic in the case of a powerful breaking bore, like that of the Qiantang River.

  14. No Snowball on Habitable Tidally Locked Planets

    Science.gov (United States)

    Checlair, Jade; Menou, Kristen; Abbot, Dorian S.

    2017-08-01

    The TRAPPIST-1, Proxima Centauri, and LHS 1140 systems are the most exciting prospects for future follow-up observations of potentially inhabited planets. All of the planets orbit nearby M-stars and are likely tidally locked in 1:1 spin–orbit states, which motivates the consideration of the effects that tidal locking might have on planetary habitability. On Earth, periods of global glaciation (snowballs) may have been essential for habitability and remote signs of life (biosignatures) because they are correlated with increases in the complexity of life and in the atmospheric oxygen concentration. In this paper, we investigate the snowball bifurcation (sudden onset of global glaciation) on tidally locked planets using both an energy balance model and an intermediate-complexity global climate model. We show that tidally locked planets are unlikely to exhibit a snowball bifurcation as a direct result of the spatial pattern of insolation they receive. Instead, they will smoothly transition from partial to complete ice coverage and back. A major implication of this work is that tidally locked planets with an active carbon cycle should not be found in a snowball state. Moreover, this work implies that tidally locked planets near the outer edge of the habitable zone with low CO2 outgassing fluxes will equilibrate with a small unglaciated substellar region rather than cycling between warm and snowball states. More work is needed to determine how the lack of a snowball bifurcation might affect the development of life on a tidally locked planet.

  15. No Snowball on Habitable Tidally Locked Planets

    Energy Technology Data Exchange (ETDEWEB)

    Checlair, Jade; Abbot, Dorian S. [Department of the Geophysical Sciences, University of Chicago, 5734 South Ellis Avenue, Chicago, IL 60637 (United States); Menou, Kristen, E-mail: jadecheclair@uchicago.edu [Centre for Planetary Sciences, Department of Physical and Environmental Sciences, University of Toronto at Scarborough, Toronto, ON M1C 1A4 (Canada)

    2017-08-20

    The TRAPPIST-1, Proxima Centauri, and LHS 1140 systems are the most exciting prospects for future follow-up observations of potentially inhabited planets. All of the planets orbit nearby M-stars and are likely tidally locked in 1:1 spin–orbit states, which motivates the consideration of the effects that tidal locking might have on planetary habitability. On Earth, periods of global glaciation (snowballs) may have been essential for habitability and remote signs of life (biosignatures) because they are correlated with increases in the complexity of life and in the atmospheric oxygen concentration. In this paper, we investigate the snowball bifurcation (sudden onset of global glaciation) on tidally locked planets using both an energy balance model and an intermediate-complexity global climate model. We show that tidally locked planets are unlikely to exhibit a snowball bifurcation as a direct result of the spatial pattern of insolation they receive. Instead, they will smoothly transition from partial to complete ice coverage and back. A major implication of this work is that tidally locked planets with an active carbon cycle should not be found in a snowball state. Moreover, this work implies that tidally locked planets near the outer edge of the habitable zone with low CO{sub 2} outgassing fluxes will equilibrate with a small unglaciated substellar region rather than cycling between warm and snowball states. More work is needed to determine how the lack of a snowball bifurcation might affect the development of life on a tidally locked planet.

  16. No Snowball on Habitable Tidally Locked Planets

    International Nuclear Information System (INIS)

    Checlair, Jade; Abbot, Dorian S.; Menou, Kristen

    2017-01-01

    The TRAPPIST-1, Proxima Centauri, and LHS 1140 systems are the most exciting prospects for future follow-up observations of potentially inhabited planets. All of the planets orbit nearby M-stars and are likely tidally locked in 1:1 spin–orbit states, which motivates the consideration of the effects that tidal locking might have on planetary habitability. On Earth, periods of global glaciation (snowballs) may have been essential for habitability and remote signs of life (biosignatures) because they are correlated with increases in the complexity of life and in the atmospheric oxygen concentration. In this paper, we investigate the snowball bifurcation (sudden onset of global glaciation) on tidally locked planets using both an energy balance model and an intermediate-complexity global climate model. We show that tidally locked planets are unlikely to exhibit a snowball bifurcation as a direct result of the spatial pattern of insolation they receive. Instead, they will smoothly transition from partial to complete ice coverage and back. A major implication of this work is that tidally locked planets with an active carbon cycle should not be found in a snowball state. Moreover, this work implies that tidally locked planets near the outer edge of the habitable zone with low CO 2 outgassing fluxes will equilibrate with a small unglaciated substellar region rather than cycling between warm and snowball states. More work is needed to determine how the lack of a snowball bifurcation might affect the development of life on a tidally locked planet.

  17. Tidal ventilation distribution during pressure-controlled ventilation and pressure support ventilation in post-cardiac surgery patients.

    Science.gov (United States)

    Blankman, P; VAN DER Kreeft, S M; Gommers, D

    2014-09-01

    Inhomogeneous ventilation is an important contributor to ventilator-induced lung injury. Therefore, this study examines homogeneity of lung ventilation by means of electrical impedance tomography (EIT) measurements during pressure-controlled ventilation (PCV) and pressure support ventilation (PSV) using the same ventilation pressures. Twenty mechanically ventilated patients were studied after cardiac surgery. On arrival at the intensive care unit, ventilation distribution was measured with EIT just above the diaphragm for 15 min. After awakening, PCV was switched to PSV and EIT measurements were again recorded. Tidal impedance variation, a measure of tidal volume, increased during PSV compared with PCV, despite using the same ventilation pressures (P = 0.045). The distribution of tidal ventilation to the dependent lung region was more pronounced during PSV compared with PCV, especially during the first half of the inspiration. An even distribution of tidal ventilation between the dependent and non-dependent lung regions was seen during PCV at lower tidal volumes (tidal volumes (≥ 8 ml/kg). In addition, the distribution of tidal ventilation was predominantly distributed to the dependent lung during PSV at low tidal volumes. In post-cardiac surgery patients, PSV showed improved ventilation of the dependent lung region due to the contribution of the diaphragm activity, which is even more pronounced during lower assist levels. © 2014 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

  18. Counter rotating type hydroelectric unit suitable for tidal power station

    International Nuclear Information System (INIS)

    Kanemoto, T; Suzuki, T

    2010-01-01

    The counter rotating type hydroelectric unit, which is composed of the axial flow type tandem runners and the peculiar generator with double rotational armatures,was proposed to utilize effectively the tidal power. In the unit, the front and the rear runners counter drive the inner and the outer armatures of the generator, respectively. Besides, the flow direction at the rear runner outlet must coincide with the flow direction at the front runner inlet, because the angular momentum through the rear runner must coincides with that through the front runner. That is, the flow runs in the axial direction at the rear runner outlet while the axial inflow at the front runner inlet. Such operations are suitable for working at the seashore with rising and falling tidal flows, and the unit may be able to take place of the traditional bulb type turbines. The tandem runners were operated at the on-cam conditions, in keeping the induced frequency constant. The output and the hydraulic efficiency are affected by the adjustment of the front and the blade setting angles. The both optimum angles giving the maximum output and/or efficiency were presented at the various discharges/heads. To promote more the tidal power generation by this type unit, the runners were also modified so as to be suitable for both rising and falling flows. The hydraulic performances are acceptable while the output is determined mainly by the trailing edge profiles of the runner blades.

  19. Tidal interactions with Kerr black holes

    International Nuclear Information System (INIS)

    Hiscock, W.A.

    1977-01-01

    The tidal deformation of an extended test body falling with zero angular momentum into a Kerr black hole is calculated. Numerical results for infall along the symmetry axis and in the equatorial plane of the black hole are presented for a range of values of a, the specific angular momentum of the black hole. Estimates of the tidal contribution to the gravitational radiation are also given. The tidal contribution in equatorial infall into a maximally rotating Kerr black hole may be of the same order as the center-of-mass contribution to the gravitational radiation

  20. Tidal influence on subtropical estuarine methane emissions

    Science.gov (United States)

    Sturm, Katrin; Grinham, Alistair; Werner, Ursula; Yuan, Zhiguo

    2014-05-01

    The relatively unstudied subtropical estuaries, particularly in the Southern Hemisphere, represent an important gap in our understanding of global greenhouse gas (GHG) emissions. These systems are likely to form an important component of GHG budgets as they occupy a relatively large surface area, over 38 000 km2 in Australia. Here, we present studies conducted in the Brisbane River estuary, a representative system within the subtropical region of Queensland, Australia. This is a highly modified system typical of 80% of Australia's estuaries. Generally, these systems have undergone channel deepening and straightening for safer shipping access and these modifications have resulted in large increases in tidal reach. The Brisbane River estuary's natural tidal reach was 16 km and this is now 85 km and tidal currents influence double the surface area (9 km2 to 18 km2) in this system. Field studies were undertaken to improve understanding of the driving factors behind methane water-air fluxes. Water-air fluxes in estuaries are usually calculated with the gas exchange coefficient (k) for currents and wind as well as the concentration difference across the water-air interface. Tidal studies in the lower and middle reaches of the estuary were performed to monitor the influence of the tidal stage (a proxy for kcurrent) on methane fluxes. Results for both investigated reaches showed significantly higher methane fluxes during the transition time of tides, the time of greatest tidal currents, than during slack tide periods. At these tidal transition times with highest methane chamber fluxes, lowest methane surface water concentrations were monitored. Modelled fluxes using only wind speed (kwind) were at least one order of magnitude lower than observed from floating chambers, demonstrating that current speed was likely the driving factor of water-air fluxes. An additional study was then conducted sampling the lower, middle and upper reaches during a tidal transition period

  1. High tidal volume ventilation in infant mice.

    Science.gov (United States)

    Cannizzaro, Vincenzo; Zosky, Graeme R; Hantos, Zoltán; Turner, Debra J; Sly, Peter D

    2008-06-30

    Infant mice were ventilated with either high tidal volume (V(T)) with zero end-expiratory pressure (HVZ), high V(T) with positive end-expiratory pressure (PEEP) (HVP), or low V(T) with PEEP. Thoracic gas volume (TGV) was determined plethysmographically and low-frequency forced oscillations were used to measure the input impedance of the respiratory system. Inflammatory cells, total protein, and cytokines in bronchoalveolar lavage fluid (BALF) and interleukin-6 (IL-6) in serum were measured as markers of pulmonary and systemic inflammatory response, respectively. Coefficients of tissue damping and tissue elastance increased in all ventilated mice, with the largest rise seen in the HVZ group where TGV rapidly decreased. BALF protein levels increased in the HVP group, whereas serum IL-6 rose in the HVZ group. PEEP keeps the lungs open, but provides high volumes to the entire lungs and induces lung injury. Compared to studies in adult and non-neonatal rodents, infant mice demonstrate a different response to similar ventilation strategies underscoring the need for age-specific animal models.

  2. Exploitation of tidal power in the Bay of Cadiz: ancient tidal mills

    Directory of Open Access Journals (Sweden)

    José J. Alonso del Rosario

    2006-03-01

    Full Text Available Tidal mills were the main industrial activity in the Bay of Cadiz for centuries. They were the last step in the production of salt and flour made by grinding grains. They were installed along the shallow channels, called “caños”, around the Bay, where the frictional and geometrical effects are very strong. The authors have analyzed the propagation of the semidiurnal tidal waves along the Caño de Sancti Petri and the available tidal power in the area. The ancient tidal mills were located where the available tidal potential energy is highest, which ensured productivity for grinding salt and wheat in ancient times. Some considerations about the possibility of installing tidal power plants in the Bay of Cadiz now are given, which show that it could be a real and renewal alternative source of energy for the area.

  3. Downstream hydraulic geometry of a tidally influenced river delta

    NARCIS (Netherlands)

    Sassi, M.G.; Hoitink, A.J.F.; Brye, de B.; Deleersnijder, E.

    2012-01-01

    Channel geometry in tidally influenced river deltas can show a mixed scaling behavior between that of river and tidal channel networks, as the channel forming discharge is both of river and tidal origin. We present a method of analysis to quantify the tidal signature on delta morphology, by

  4. Development of tidal watersheds in the Wadden Sea

    NARCIS (Netherlands)

    Wang, Z.B.; Vroom, J.; van Prooijen, B.C.; Labeur, R.J.; Stive, M.J.F.; Hansen, M.H.P.

    2011-01-01

    The Wadden Sea consists of a series of tidal lagoons which are connected to the North Sea by tidal inlets. Boundaries to each lagoon are the mainland coast, the barrier islands on both sides of the tidal inlet, and the tidal watersheds behind the two barrier islands. Behind each Wadden Island there

  5. Tidal Mixing at the Shelf Break

    National Research Council Canada - National Science Library

    Hogg, Nelson; Legg, Sonya

    2005-01-01

    ...; the second a set of simulations of flow over the Hawaiian ridge. The most exciting scientific result is the importance of internal hydraulic jumps in generating tidal mixing at large amplitude, steep topography...

  6. Tidal Mixing at the Shelf Break

    National Research Council Canada - National Science Library

    Hogg, Nelson; Legg, Sonya

    2005-01-01

    The aim of this project was to study mixing forced by tidal flow over sudden changes in topographic slope such as near the shelf-break, using high-resolution nonhydrostatic numerical simulations employing the MIT gem...

  7. Microbial quality of a marine tidal pool

    CSIR Research Space (South Africa)

    Genthe, Bettina

    1995-01-01

    Full Text Available In this study the source of microbial pollution to a tidal pool was investigated. Both adjacent seawater which could contribute to possible faecal pollution and potential direct bather pollution were studied. The microbial quality of the marine...

  8. Tides and tidal harmonics at Umbharat, Gujarat

    Digital Repository Service at National Institute of Oceanography (India)

    Suryanarayana, A.; Swamy, G.N.

    A part of the data on tides recorded at Machiwada near Umbharat, Gulf of Cambay during April 1978 was subjected to harmonic analysis following the Admiralty procedure. The general tidal characteristics and the value of four major harmonic...

  9. EQUATORIAL SUPERROTATION ON TIDALLY LOCKED EXOPLANETS

    International Nuclear Information System (INIS)

    Showman, Adam P.; Polvani, Lorenzo M.

    2011-01-01

    The increasing richness of exoplanet observations has motivated a variety of three-dimensional (3D) atmospheric circulation models of these planets. Under strongly irradiated conditions, models of tidally locked, short-period planets (both hot Jupiters and terrestrial planets) tend to exhibit a circulation dominated by a fast eastward, or 'superrotating', jet stream at the equator. When the radiative and advection timescales are comparable, this phenomenon can cause the hottest regions to be displaced eastward from the substellar point by tens of degrees longitude. Such an offset has been subsequently observed on HD 189733b, supporting the possibility of equatorial jets on short-period exoplanets. Despite its relevance, however, the dynamical mechanisms responsible for generating the equatorial superrotation in such models have not been identified. Here, we show that the equatorial jet results from the interaction of the mean flow with standing Rossby waves induced by the day-night thermal forcing. The strong longitudinal variations in radiative heating-namely intense dayside heating and nightside cooling-trigger the formation of standing, planetary-scale equatorial Rossby and Kelvin waves. The Rossby waves develop phase tilts that pump eastward momentum from high latitudes to the equator, thereby inducing equatorial superrotation. We present an analytic theory demonstrating this mechanism and explore its properties in a hierarchy of one-layer (shallow-water) calculations and fully 3D models. The wave-mean-flow interaction produces an equatorial jet whose latitudinal width is comparable to that of the Rossby waves, namely the equatorial Rossby deformation radius modified by radiative and frictional effects. For conditions typical of synchronously rotating hot Jupiters, this length is comparable to a planetary radius, explaining the broad scale of the equatorial jet obtained in most hot-Jupiter models. Our theory illuminates the dependence of the equatorial jet

  10. Brown coal gasification made easy

    International Nuclear Information System (INIS)

    Hamilton, Chris

    2006-01-01

    Few Victorians will be aware that gas derived from coal was first used in 1849 to provide lighting in a baker's shop in Swanston Street, long before electric lighting came to the State. The first commercial 'gas works' came on stream in 1856 and Melbourne then had street lighting run on gas. By 1892 there were 50 such gas works across the State. Virtually all were fed with black coal imported from New South Wales. Brown coal was first discovered west of Melbourne in 1857, and the Latrobe Valley deposits were identified in the early 1870s. Unfortunately, such wet brown coal did not suit the gas works. Various attempts to commercialise Victorian brown coal met with mixed success as it struggled to compete with imported New South Wales black coal. In June 1924 Yallourn A transmitted the first electric power to Melbourne, and thus began the Latrobe Valley's long association with generating electric power from brown coal. Around 1950, the Metropolitan Gas Company applied for financial assistance to build a towns gas plant using imported German gasification technology which had been originally designed for a brown coal briquette feed. The State Government promptly acquired the company and formed the Gas and Fuel Corporation. The Morwell Gasification Plant was opened on 9 December 1956 and began supplying Melbourne with medium heating value towns gas

  11. Resonant Tidal Disruption in Galactic Nuclei

    OpenAIRE

    Rauch, Kevin P.; Ingalls, Brian

    1997-01-01

    It has recently been shown that the rate of angular momentum relaxation in nearly-Keplerian star clusters is greatly increased by a process termed resonant relaxation (Rauch & Tremaine 1996), who also argued that tidal disruption of stars in galactic nuclei containing massive black holes could be noticeably enhanced by this process. We describe here the results of numerical simulations of resonant tidal disruption which quantitatively test the predictions made by Rauch & Tremaine. The simulat...

  12. On the ambiguity in relativistic tidal deformability

    Science.gov (United States)

    Gralla, Samuel E.

    2018-04-01

    The LIGO collaboration recently reported the first gravitational-wave constraints on the tidal deformability of neutron stars. I discuss an inherent ambiguity in the notion of relativistic tidal deformability that, while too small to affect the present measurement, may become important in the future. I propose a new way to understand the ambiguity and discuss future prospects for reliably linking observed gravitational waveforms to compact object microphysics.

  13. WIYN Open Cluster Study: Tidal Interactions in Solar type Binaries

    OpenAIRE

    Meibom, S.; Mathieu, R. D.

    2003-01-01

    We present an ongoing study on tidal interactions in late-type close binary stars. New results on tidal circularization are combined with existing data to test and constrain theoretical predictions of tidal circularization in the pre-main-sequence (PMS) phase and throughout the main-sequence phase of stellar evolution. Current data suggest that tidal circularization during the PMS phase sets the tidal cutoff period for binary populations younger than ~1 Gyr. Binary populations older than ~1 G...

  14. Half Moon Cove Tidal Project. Feasibility report

    Energy Technology Data Exchange (ETDEWEB)

    1980-11-01

    The proposed Half Moon Cove Tidal Power Project would be located in a small cove in the northern part of Cobscook Bay in the vicinity of Eastport, Maine. The project would be the first tidal electric power generating plant in the United States of America. The basin impounded by the barrier when full will approximate 1.2 square miles. The average tidal range at Eastport is 18.2 feet. The maximum spring tidal range will be 26.2 feet and the neap tidal range 12.8 feet. The project will be of the single pool-type single effect in which generation takes place on the ebb tide only. Utilizing an average mean tidal range of 18.2 feet the mode of operation enables generation for approximately ten and one-half (10-1/2) hours per day or slightly in excess of five (5) hours per tide. The installed capacity will be 12 MW utilizing 2 to 6 MW units. An axial flow, or Bulb type of turbine was selected for this study.

  15. VISCOELASTIC MODELS OF TIDALLY HEATED EXOMOONS

    Energy Technology Data Exchange (ETDEWEB)

    Dobos, Vera [Konkoly Thege Miklos Astronomical Institute, Research Centre of Astronomy and Earth Sciences, Hungarian Academy of Sciences, H-1121 Konkoly Thege Miklós út 15-17, Budapest (Hungary); Turner, Edwin L., E-mail: dobos@konkoly.hu [Department of Astrophysical Sciences, Princeton University, 08544, 4 Ivy Lane, Peyton Hall, Princeton, NJ (United States)

    2015-05-01

    Tidal heating of exomoons may play a key role in their habitability, since the elevated temperature can melt the ice on the body even without significant solar radiation. The possibility of life has been intensely studied on solar system moons such as Europa or Enceladus where the surface ice layer covers a tidally heated water ocean. Tidal forces may be even stronger in extrasolar systems, depending on the properties of the moon and its orbit. To study the tidally heated surface temperature of exomoons, we used a viscoelastic model for the first time. This model is more realistic than the widely used, so-called fixed Q models because it takes into account the temperature dependence of the tidal heat flux and the melting of the inner material. Using this model, we introduced the circumplanetary Tidal Temperate Zone (TTZ), which strongly depends on the orbital period of the moon and less on its radius. We compared the results with the fixed Q model and investigated the statistical volume of the TTZ using both models. We have found that the viscoelastic model predicts 2.8 times more exomoons in the TTZ with orbital periods between 0.1 and 3.5 days than the fixed Q model for plausible distributions of physical and orbital parameters. The viscoelastic model provides more promising results in terms of habitability because the inner melting of the body moderates the surface temperature, acting like a thermostat.

  16. TIDAL INTERACTIONS IN MERGING WHITE DWARF BINARIES

    International Nuclear Information System (INIS)

    Piro, Anthony L.

    2011-01-01

    The recently discovered system J0651 is the tightest known detached white dwarf (WD) binary. Since it has not yet initiated Roche-lobe overflow, it provides a relatively clean environment for testing our understanding of tidal interactions. I investigate the tidal heating of each WD, parameterized in terms of its tidal Q parameter. Assuming that the heating can be radiated efficiently, the current luminosities are consistent with Q 1 ∼ 7 x 10 10 and Q 2 ∼ 2 x 10 7 , for the He and C/O WDs, respectively. Conversely, if the observed luminosities are merely from the cooling of the WDs, these estimated values of Q represent the upper limits. A large Q 1 for the He WD means its spin velocity will be slower than that expected if it was tidally locked, which, since the binary is eclipsing, may be measurable via the Rossiter-McLaughlin effect. After one year, gravitational wave emission shifts the time of eclipses by 5.5 s, but tidal interactions cause the orbit to shrink more rapidly, changing the time by up to an additional 0.3 s after a year. Future eclipse timing measurements may therefore infer the degree of tidal locking.

  17. VISCOELASTIC MODELS OF TIDALLY HEATED EXOMOONS

    International Nuclear Information System (INIS)

    Dobos, Vera; Turner, Edwin L.

    2015-01-01

    Tidal heating of exomoons may play a key role in their habitability, since the elevated temperature can melt the ice on the body even without significant solar radiation. The possibility of life has been intensely studied on solar system moons such as Europa or Enceladus where the surface ice layer covers a tidally heated water ocean. Tidal forces may be even stronger in extrasolar systems, depending on the properties of the moon and its orbit. To study the tidally heated surface temperature of exomoons, we used a viscoelastic model for the first time. This model is more realistic than the widely used, so-called fixed Q models because it takes into account the temperature dependence of the tidal heat flux and the melting of the inner material. Using this model, we introduced the circumplanetary Tidal Temperate Zone (TTZ), which strongly depends on the orbital period of the moon and less on its radius. We compared the results with the fixed Q model and investigated the statistical volume of the TTZ using both models. We have found that the viscoelastic model predicts 2.8 times more exomoons in the TTZ with orbital periods between 0.1 and 3.5 days than the fixed Q model for plausible distributions of physical and orbital parameters. The viscoelastic model provides more promising results in terms of habitability because the inner melting of the body moderates the surface temperature, acting like a thermostat

  18. Central Fibroblast Growth Factor 21 Browns White Fat via Sympathetic Action in Male Mice.

    Science.gov (United States)

    Douris, Nicholas; Stevanovic, Darko M; Fisher, Ffolliott M; Cisu, Theodore I; Chee, Melissa J; Nguyen, Ngoc L; Zarebidaki, Eleen; Adams, Andrew C; Kharitonenkov, Alexei; Flier, Jeffrey S; Bartness, Timothy J; Maratos-Flier, Eleftheria

    2015-07-01

    Fibroblast growth factor 21 (FGF21) has multiple metabolic actions, including the induction of browning in white adipose tissue. Although FGF21 stimulated browning results from a direct interaction between FGF21 and the adipocyte, browning is typically associated with activation of the sympathetic nervous system through cold exposure. We tested the hypothesis that FGF21 can act via the brain, to increase sympathetic activity and induce browning, independent of cell-autonomous actions. We administered FGF21 into the central nervous system via lateral ventricle infusion into male mice and found that the central treatment increased norepinephrine turnover in target tissues that include the inguinal white adipose tissue and brown adipose tissue. Central FGF21 stimulated browning as assessed by histology, expression of uncoupling protein 1, and the induction of gene expression associated with browning. These effects were markedly attenuated when mice were treated with a β-blocker. Additionally, neither centrally nor peripherally administered FGF21 initiated browning in mice lacking β-adrenoceptors, demonstrating that an intact adrenergic system is necessary for FGF21 action. These data indicate that FGF21 can signal in the brain to activate the sympathetic nervous system and induce adipose tissue thermogenesis.

  19. Suspended particulate matter flocculation in a natural tidal wetland located in the San Francisco Estuary

    Science.gov (United States)

    Saraceno, J.; Bergamaschi, B. A.; Wright, S. A.; Boss, E.; Downing, B. D.; Fleck, J.; Ganju, N. K.

    2011-12-01

    Suspended mineral and algal particles together comprise suspended particulate matter (SPM). The SPM size distribution influences the quantity and color of light penetration and the adsorption and transport of contaminants such as pesticides and metals. It is widely known that interaction with wetlands alters the size distribution and quality of particles through local primary production, differential settling and particle aggregation, however, our understanding of how tidal wetland processes affect SPM quantity and size spectra has been hampered by the difficulty of directly observing these parameters at tidal time scales. To evaluate how SPM concentration and size varied over tidal time scales and to better understand the relationship between organic matter and sediment characteristics, simultaneous measurements of dissolved organic matter, SPM concentration and organic content as well as in situ surrogates of particle concentration (turbidity, particulate attenuation, volume concentration) and particle size (laser diffraction) were carried out with measurements of current velocity (acoustic Doppler velocity meter) in the main channel of Brown's Island located in the western San Joaquin/Sacramento River Delta, CA. The study period coincided with high estuary sediment levels following a significant precipitation runoff event. In the Brown Island wetland, particle concentration and size dynamics were tied to variations in water level and velocity. Turbidity and attenuation covaried with the volume concentration of particles smaller than 33 um, which on average represented greater than 50% of particle population by volume. On average, these SPM concentration surrogates were three times higher in flood water than in ebb water; consistent with a loss of fine particles on the island. Following the highest flood tide, the decrease in fine particles was coincident with an increase in the concentration of particles larger than 130 um; a finding consistent with particle

  20. Browns Ferry charcoal adsorber incident

    International Nuclear Information System (INIS)

    Mays, G.T.

    1979-01-01

    The article reviews the temperature excursion in the charcoal adsorber beds of the Browns Ferry Unit 3 off-gas system that occurred on July 17, 1977. Significant temperature increases were experienced in the charcoal adsorber beds when charcoal fines were ignited by the ignition of a combustible mixture of hydrogen and oxygen in the off-gas system. The Browns Ferry off-gas system is described, and events leading up to and surrounding the incident are discussed. The follow-up investigation by Tennessee Valley Authority and General Electric Company personnel and their recommendations for system and operational modifications are summarized

  1. The dynamical fate of self-gravitating disc fragments after tidal downsizing

    Science.gov (United States)

    Forgan, Duncan; Parker, Richard J.; Rice, Ken

    2015-02-01

    The gravitational instability model of planet/brown dwarf formation proposes that protostellar discs can fragment into objects with masses above a few Jupiter masses at large semimajor axis. Tidal downsizing may reduce both the object mass and semimajor axis. However, most studies of tidal downsizing end when the protostellar disc disperses, while the system is embedded in its parent star-forming region. To compare disc fragment descendants with exoplanet and brown dwarf observations, the subsequent dynamical evolution must be explored. We carry out N-body integrations of fragment-fragment scattering in multi-object star systems, and star systems embedded in substructured clusters. In both cases, we use initial conditions generated by population synthesis models of tidal downsizing. The scattering simulations produce a wide range of eccentricities. The ejection rate is around 25 per cent. The ejecta mass distribution is similar to that for all objects, with a velocity dispersion consistent with those produced by full hydrodynamic simulations. The semimajor axis distribution after scattering extends to parsec scales. In the cluster simulations, 13 per cent of the objects are ejected from their planetary system, and around 10 per cent experience significant orbit modification. A small number of objects are recaptured on high-eccentricity, high-inclination orbits. The velocity distribution of ejecta is similar to that produced by fragment-fragment scattering. If fragment-fragment scattering and cluster stripping act together, then disc fragmentation should be efficient at producing free-floating substellar objects, and hence characterizing the free-floating planet population will provide strong constraints on the frequency of disc fragmentation.

  2. Plant distributions along salinity and tidal gradients in Oregon tidal marshes

    Science.gov (United States)

    Accurately modeling climate change effects on tidal marshes in the Pacific Northwest requires understanding how plant assemblages and species are presently distributed along gradients of salinity and tidal inundation. We outline on-going field efforts by the EPA and USGS to dete...

  3. Tidal exchange between a freshwater tidal marsh and an impacted estuary: the Scheldt estuary, Belgium

    NARCIS (Netherlands)

    van Damme, S.; Dehairs, F.; Tackx, M.; Beauchard, O.; Struyf, E.; Gribsholt, B.; van Cleemput, O.; Meire, P.

    2009-01-01

    Tidal marsh exchange studies are relatively simple tools to investigate the interaction between tidal marshes and estuaries. They have mostly been confined to only a few elements and to saltwater or brackish systems. This study presents mass-balance results of an integrated one year campaign in a

  4. Geometry of tidal inlet systems : A key factor for the net sediment transport in tidal inlets

    NARCIS (Netherlands)

    Ridderinkhof, W.; de Swart, H. E.; van der Vegt, M.; Alebregtse, N. C.; Hoekstra, P.

    2014-01-01

    The net transport of sediment between the back-barrier basin and the sea is an important process for determining the stability of tidal inlet systems. Earlier studies showed that in a short basin, tidal flats favor peak ebb-currents stronger than peak flood currents, implying export of coarse

  5. Dynamics of tidal and non-tidal currents along the southwest continental shelf of India

    Digital Repository Service at National Institute of Oceanography (India)

    Aruna, C.; Ravichandran, C.; Srinivas, K.; Rasheed, P.A.A.; Lekshmi, S.

    are predominantly mixed, semidiurnal in nature. Motion over any continental shelf is governed by the tide-driven oscillatory flow. In this paper, tidal and non-tidal characteristics of the waters of Southwest continental shelf of India are assessed using...

  6. Impact of brown rice-specific γ-oryzanol on epigenetic modulation of dopamine D2 receptors in brain striatum in high-fat-diet-induced obesity in mice.

    Science.gov (United States)

    Kozuka, Chisayo; Kaname, Tadashi; Shimizu-Okabe, Chigusa; Takayama, Chitoshi; Tsutsui, Masato; Matsushita, Masayuki; Abe, Keiko; Masuzaki, Hiroaki

    2017-08-01

    Overeating of dietary fats causes obesity in humans and rodents. Recent studies in humans and rodents have demonstrated that addiction to fats shares a common mechanism with addiction to alcohol, nicotine and narcotics in terms of a dysfunction of brain reward systems. It has been highlighted that a high-fat diet (HFD) attenuates dopamine D2 receptor (D2R) signalling in the striatum, a pivotal regulator of the brain reward system, resulting in hedonic overeating. We previously reported that the brown rice-specific bioactive constituent γ-oryzanol attenuated the preference for an HFD via hypothalamic control. We therefore explored the possibility that γ-oryzanol would modulate functioning of the brain reward system in mice. Male C57BL/6J mice fed an HFD were orally treated with γ-oryzanol, and striatal levels of molecules involved in D2R signalling were evaluated. The impact of γ-oryzanol on DNA methylation of the D2R promoter and subsequent changes in preferences for dietary fat was examined. In addition, the effects of 5-aza-2'-deoxycytidine, a potent inhibitor of DNA methyltransferases (DNMTs), on food preference, D2R signalling and the levels of DNMTs in the striatum were investigated. The inhibitory effects of γ-oryzanol on the activity of DNMTs were enzymatically evaluated in vitro. In striatum from mice fed an HFD, the production of D2Rs was decreased via an increase in DNA methylation of the promoter region of the D2R. Oral administration of γ-oryzanol decreased the expression and activity of DNMTs, thereby restoring the level of D2Rs in the striatum. Pharmacological inhibition of DNMTs by 5-aza-2'-deoxycytidine also ameliorated the preference for dietary fat. Consistent with these findings, enzymatic in vitro assays demonstrated that γ-oryzanol inhibited the activity of DNMTs. We demonstrated that γ-oryzanol ameliorates HFD-induced DNA hypermethylation of the promoter region of D2R in the striatum of mice. Our experimental paradigm highlights

  7. Chemical enrichment by tidally disrupted stars near a black hole in the Galactic Center

    International Nuclear Information System (INIS)

    Luminet, J.P.; Barbuy, B.

    1990-01-01

    The amount of species produced in the nucleosynthesis tidally induced by a large black hole on infalling stars is computed. The total mass of isotopic species N-14, N-15, Mg-25, Mg-26, and Al-26, Al-27 produced in this process along the first billion years of the Galaxy life are compared to possible observational evidences. 35 refs

  8. Tidal breathing flow measurement in awake young children by using impedance pneumography.

    Science.gov (United States)

    Seppä, Ville-Pekka; Pelkonen, Anna S; Kotaniemi-Syrjänen, Anne; Mäkelä, Mika J; Viik, Jari; Malmberg, L Pekka

    2013-12-01

    Characteristics of tidal breathing (TB) relate to lung function and may be assessed even in young children. Thus far, the accuracy of impedance pneumography (IP) in recording TB flows in young children with or without bronchial obstruction has not been evaluated. The aim of this study was to evaluate the agreement between IP and direct flow measurement with pneumotachograph (PNT) in assessing TB flow and flow-derived indices relating to airway obstruction in young children. Tidal flow was recorded for 1 min simultaneously with IP and PNT during different phases of a bronchial challenge test with methacholine in 21 wheezy children aged 3 to 7 years. The agreement of IP with PNT was found to be excellent in direct flow signal comparison, the mean deviation from linearity ranging from 2.4 to 3.1% of tidal peak inspiratory flow. Methacholine-induced bronchoconstriction or consecutive bronchodilation induced only minor changes in the agreement. Between IP and PNT, the obstruction-related tidal flow indices were equally repeatable, and agreement was found to be high, with intraclass correlation coefficients for T PTEF/T E, V PTEF/V E, and parameter S being 0.94, 0.91, and 0.68, respectively. Methacholine-induced changes in tidal flow indices showed significant associations with changes in mechanical impedance of the respiratory system assessed by the oscillometric technique, with the highest correlation found in V PTEF/V E (r = -0.54; P tidal airflow profiles in young children with wheezing disorders.

  9. Agaricus bisporus browning: a review

    NARCIS (Netherlands)

    Jolivet, S.; Arpin, N.; Wichers, H.J.; Pellon, G.

    1998-01-01

    Agaricus bisporus browning is a common and economically detrimental phenomenon, in which melanogenic phenols are enzymically processed into quinones, which evolve eventually to melanins. This review deals with the two fundamental sides of this process, enzyme(s) and phenolic substrates. Mushroom

  10. Cleanup at Browns Ferry 3

    International Nuclear Information System (INIS)

    Mitchell, Brad; Janvrin, R.W.

    1995-01-01

    When major work had to be done in the drywell of Browns Ferry 3, the utility, Tennessee Valley Authority (TVA), decided that it made sense to make it ''street clothes clean'' for workers. This not only made work easier, it saved time and millions of dollars. (author)

  11. 7 CFR 29.2254 - Brown colors.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Brown colors. 29.2254 Section 29.2254 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... colors. A group of colors ranging from a reddish brown to yellowish brown. These colors vary from low to...

  12. The brown dwarf kinematics project

    Science.gov (United States)

    Faherty, Jackie K.

    2010-10-01

    Brown dwarfs are a recent addition to the plethora of objects studied in Astronomy. With theoretical masses between 13 and 75 MJupiter , they lack sustained stable Hydrogen burning so they never join the stellar main sequence. They have physical properties similar to both planets and low-mass stars so studies of their population inform on both. The distances and kinematics of brown dwarfs provide key statistical constraints on their ages, moving group membership, absolute brightnesses, evolutionary trends, and multiplicity. Yet, until my thesis, fundamental measurements of parallax and proper motion were made for only a relatively small fraction of the known population. To address this deficiency, I initiated the Brown Dwarf Kinematics (BDKP). Over the past four years I have re-imaged the majority of spectroscopically confirmed field brown dwarfs (or ultracool dwarfs---UCDs) and created the largest proper motion catalog for ultracool dwarfs to date. Using new astrometric information I examined population characteristics such as ages calculated from velocity dispersions and correlations between kinematics and colors. Using proper motions, I identified several new wide co-moving companions and investigated binding energy (and hence formation) limitations as well as the frequency of hierarchical companions. Concurrently over the past four years I have been conducting a parallax survey of 84 UCDs including those showing spectral signatures of youth, metal-poor brown dwarfs, and those within 20 pc of the Sun. Using absolute magnitude relations in J,H, and K, I identified overluminous binary candidates and investigated known flux-reversal binaries. Using current evolutionary models, I compared the MK vs J-K color magnitude diagram to model predictions and found that the low-surface gravity dwarfs are significantly red-ward and underluminous of predictions and a handful of late-type T dwarfs may require thicker clouds to account for their scatter.

  13. Carbon sequestration by Australian tidal marshes

    KAUST Repository

    Macreadie, Peter I.

    2017-03-10

    Australia\\'s tidal marshes have suffered significant losses but their recently recognised importance in CO2 sequestration is creating opportunities for their protection and restoration. We compiled all available data on soil organic carbon (OC) storage in Australia\\'s tidal marshes (323 cores). OC stocks in the surface 1 m averaged 165.41 (SE 6.96) Mg OC ha-1 (range 14-963 Mg OC ha-1). The mean OC accumulation rate was 0.55 ± 0.02 Mg OC ha-1 yr-1. Geomorphology was the most important predictor of OC stocks, with fluvial sites having twice the stock of OC as seaward sites. Australia\\'s 1.4 million hectares of tidal marshes contain an estimated 212 million tonnes of OC in the surface 1 m, with a potential CO2-equivalent value of $USD7.19 billion. Annual sequestration is 0.75 Tg OC yr-1, with a CO2-equivalent value of $USD28.02 million per annum. This study provides the most comprehensive estimates of tidal marsh blue carbon in Australia, and illustrates their importance in climate change mitigation and adaptation, acting as CO2 sinks and buffering the impacts of rising sea level. We outline potential further development of carbon offset schemes to restore the sequestration capacity and other ecosystem services provided by Australia tidal marshes.

  14. Regulation of brown adipocyte metabolism by myostatin/follistatin signaling

    Directory of Open Access Journals (Sweden)

    Rajan eSingh

    2014-10-01

    Full Text Available Obesity develops from perturbations of cellular bioenergetics, when energy uptake exceeds energy expenditure, and represents a major risk factor for the development of type 2 diabetes, dyslipidemia, cardiovascular disease, cancer, and other conditions. Brown adipose tissue (BAT has long been known to dissipate energy as heat and contribute to energy expenditure, but its presence and physiological role in adult human physiology has been questioned for years. Recent demonstrations of metabolically active brown fat depots in adult humans have revolutionized current therapeutic approaches for obesity-related diseases. The balance between white adipose tissue (WAT and BAT affects the systemic energy balance and is widely believed to be the key determinant in the development of obesity and related metabolic diseases. Members of the transforming growth factor-beta (TGF-β superfamily play an important role in regulating overall energy homeostasis by modulation of brown adipocyte characteristics. Inactivation of TGF-β/Smad3/myostatin (Mst signaling promotes browning of white adipocytes, increases mitochondrial biogenesis and protects mice from diet-induced obesity, suggesting the need for development of a novel class of TGF-β/Mst antagonists for the treatment of obesity and related metabolic diseases. We recently described an important role of follistatin (Fst, a soluble glycoprotein that is known to bind and antagonize Mst actions, during brown fat differentiation and the regulation of cellular metabolism. Here we highlight various investigations performed using different in vitro and in vivo models to support the contention that targeting TGF-β/Mst signaling enhances brown adipocyte functions and regulates energy balance, reducing insulin resistance and curbing the development of obesity and diabetes.

  15. Tidal interactions in the expanding universe - The formation of prolate systems

    Science.gov (United States)

    Binney, J.; Silk, J.

    1979-01-01

    The study estimates the magnitude of the anisotropy that can be tidally induced in neighboring initially spherical protostructures, be they protogalaxies, protoclusters, or even uncollapsed density enhancements in the large-scale structure of the universe. It is shown that the linear analysis of tidal interactions developed by Peebles (1969) predicts that the anisotropy energy of a perturbation grows to first order in a small dimensionless parameter, whereas the net angular momentum acquired is of second order. A simple model is presented for the growth of anisotropy by tidal interactions during the nonlinear stage of the development of perturbations. A possible observational test is described of the alignment predicted by the model between the orientations of large-scale perturbations and the positions of neighboring density enhancements.

  16. Enhanced winds and tidal streams in massive X-ray binaries

    International Nuclear Information System (INIS)

    Blondin, J.M.; Stevens, I.R.; Kallman, T.R.

    1991-01-01

    The tidal effects created by the presence of a compact companion are expected to induce a stream of enhanced wind from the early-type primary star in massive X-ray binary systems. In this paper, two-dimensional gasdynamical simulations of such streams are presented. It is found that the wind enhancement is a sensitive function of the binary separation, and develops into a tidal stream as the primary approaches its critical surface. For typical system parameters, the Coriolis force deflects the stream sufficiently that it does not impact directly on the compact companion but passes behind it. The density in the stream can reach values of 20-30 times the ambient wind density, leading to strong attenuation of the X-ray flux that passes through the tidal stream, providing a possible explanation of the enhanced absorption events seen at later phases in the X-ray observations of massive X-ray binary systems such as Vela X-1. In contrast to the time-variable accretion wake, the tidal stream is relatively stationary, producing absorption features that should remain fixed from orbit to orbit. For systems with a strong tidal stream, the large asymmetry in the accreting wind results in the accretion of angular momentum of constant sign, as opposed to systems without streams, where the sign of the accreted angular momentum can change. 39 refs

  17. Tidal effects in twin-degenerate binaries

    International Nuclear Information System (INIS)

    Campbell, C.G.

    1984-01-01

    The tidal velocity field is calculated for an initially non-rotating low mass white dwarf secondary in a twin-degenerate binary. These motions are used to find the tidal torque on the secondary, to first order in the orbital frequency, and an expression is derived for the synchronization time. For a lobe-filling secondary the synchronization time has a weak dependence on the mass and luminosity of the star, and for the binary G61-29 is found to be of the same order as the estimated lifetime of the system. It is emphasized, however, that tidal excitation of non-radial oscillatory modes in the secondary may significantly shorten the synchronization time. (author)

  18. Tidal analysis of Met rocket wind data

    Science.gov (United States)

    Bedinger, J. F.; Constantinides, E.

    1976-01-01

    A method of analyzing Met Rocket wind data is described. Modern tidal theory and specialized analytical techniques were used to resolve specific tidal modes and prevailing components in observed wind data. A representation of the wind which is continuous in both space and time was formulated. Such a representation allows direct comparison with theory, allows the derivation of other quantities such as temperature and pressure which in turn may be compared with observed values, and allows the formation of a wind model which extends over a broader range of space and time. Significant diurnal tidal modes with wavelengths of 10 and 7 km were present in the data and were resolved by the analytical technique.

  19. The wave and tidal resource of Scotland

    Science.gov (United States)

    Neill, Simon; Vogler, Arne; Lewis, Matt; Goward-Brown, Alice

    2017-04-01

    As the marine renewable energy industry evolves, in parallel with an increase in the quantity of available data and improvements in validated numerical simulations, it is occasionally appropriate to re-assess the wave and tidal resource of a region. This is particularly true for Scotland - a leading nation that the international community monitors for developments in the marine renewable energy industry, and which has witnessed much progress in the sector over the last decade. With 7 leased wave and 17 leased tidal sites, Scotland is well poised to generate significant levels of electricity from its abundant natural marine resources. In this review of Scotland's wave and tidal resource, I present the theoretical and technical resource, and provide an overview of commercial progress. I also discuss issues that affect future development of the marine energy seascape in Scotland, applicable to other regions of the world, including the potential for developing lower energy sites, and grid connectivity.

  20. TIDAL TURBULENCE SPECTRA FROM A COMPLIANT MOORING

    Energy Technology Data Exchange (ETDEWEB)

    Thomson, Jim; Kilcher, Levi; Richmond, Marshall C.; Talbert, Joe; deKlerk, Alex; Polagye, Brian; Guerra, Maricarmen; Cienfuegos, Rodrigo

    2013-06-13

    A compliant mooring to collect high frequency turbulence data at a tidal energy site is evaluated in a series of short demon- stration deployments. The Tidal Turbulence Mooring (TTM) improves upon recent bottom-mounted approaches by suspend- ing Acoustic Doppler Velocimeters (ADVs) at mid-water depths (which are more relevant to tidal turbines). The ADV turbulence data are superior to Acoustic Doppler Current Profiler (ADCP) data, but are subject to motion contamination when suspended on a mooring in strong currents. In this demonstration, passive stabilization is shown to be sufficient for acquiring bulk statistics of the turbulence, without motion correction. With motion cor- rection (post-processing), data quality is further improved; the relative merits of direct and spectral motion correction are dis- cussed.

  1. Ocean energy. Tide and tidal power

    Energy Technology Data Exchange (ETDEWEB)

    Finkl, Charles W. [Coastal Planning and Engineering, Inc., Boca Raton, FL (United States); Charlier, Roger H.

    2009-07-01

    Engineers' dreams and fossil energy replacement schemes can come true. Man has been tapping the energy of the sea to provide power for his industries for centuries. Tidal energy combined with that of waves and marine winds rank among those most successfully put the work. Large scale plants are capital intensive but smaller ones, particularly built in China, have proven profitable. Since the initiation of the St Malo project in France, similar projects have gone into active service where methods have been devised to cut down on costs, new types of turbines developed and cost competitiveness considerably improved. Tidal power has enormous potential. The book reviews recent progress in extracting power from the ocean, surveys the history of tidal power harnessing and updates a prior publication by the author. (orig.)

  2. From Globular Clusters to Tidal Dwarfs: Structure Formation in Tidal Tails

    Science.gov (United States)

    Knierman, K.; Hunsberger, S.; Gallagher, S.; Charlton, J.; Whitmore, B.; Hibbard, J.; Kundu, A.; Zaritsky, D.

    1999-12-01

    Galaxy interactions trigger star formation in tidal debris. How does this star formation depend on the local and global physical conditions? Using WFPC2/HST images, we investigate the range of structure within tidal tails of four classic ``Toomre Sequence'' mergers: NGC 4038/9 (``Antennae''), NGC 7252 (``Atoms for Peace''), NGC 3921, and NGC 3256. These tails contain a variety of stellar associations with sizes from globular clusters up to dwarf Irregulars. We explore whether there is a continuum between the two extremes. Our eight fields sample seven tidal tails at a variety of stages in the evolutionary sequence. Some of these tails are rich in HI while others are HI poor. Large tidal dwarfs are embedded in three of the tails. Using V and I WFPC2 images, we measure luminosities and colors of substructures within the tidal tails. The properties of globular cluster candidates in the tails will be contrasted with those of the hundreds of young clusters in the central regions of these mergers. We address whether globular clusters form and survive in the tidal tails and whether tidal dwarfs are composed of only young stars. By comparing the properties of structures in the tails of the four mergers with different ages, we examine systematic evolution of structure along the evolutionary sequence and as a function of HI content. We acknowledge support from NASA through STScI, and from NSF for an REU supplement for Karen Knierman.

  3. The role of bank collapse on tidal creek ontogeny: A novel process-based model for bank retreat

    Science.gov (United States)

    Gong, Zheng; Zhao, Kun; Zhang, Changkuan; Dai, Weiqi; Coco, Giovanni; Zhou, Zeng

    2018-06-01

    Bank retreat in coastal tidal flats plays a primary role on the planimetric shape of tidal creeks and is commonly driven by both flow-induced bank erosion and gravity-induced bank collapse. However, existing modelling studies largely focus on bank erosion and overlook bank collapse. We build a bank retreat model coupling hydrodynamics, bank erosion and bank collapse. To simulate the process of bank collapse, a stress-deformation model is utilized to calculate the stress variation of bank soil after bank erosion, and the Mohr-Coulomb failure criterion is then applied to evaluate the stability of the tidal creek bank. Results show that the bank failure process can be categorized into three stages, i.e., shear failure at the bank toe (stage I), tensile failure on the bank top (stage II), and sectional cracking from the bank top to the toe (stage III). With only bank erosion, the planimetric shapes of tidal creeks are funneled due to the gradually seaward increasing discharge. In contrast to bank erosion, bank collapse is discontinuous, and the contribution of bank collapse to bank retreat can reach 85%, highlighting that the expansion of tidal creeks can be dominated by bank collapse process. The planimetric shapes of tidal creeks are funneled with a much faster expansion rate when bank collapse is considered. Overall, this study makes a further step toward more physical and realistic simulation of bank retreat in estuarine and coastal settings and the developed bank collapse module can be readily included in other morphodynamic models.

  4. A quantitative estimation of the energetic cost of brown ring disease in the Manila clam using Dynamic Energy Budget theory.

    NARCIS (Netherlands)

    Flye Sainte Marie, J.G.; Jean, F.; Paillard, C.; Kooijman, S.A.L.M.

    2009-01-01

    Brown ring disease (BRD) in the Manila clam, Ruditapes philippinarum, is a bacterial disease caused by the pathogen Vibrio tapetis. This disease induces the formation of a characteristic brown conchiolin deposit on the inner shell and is associated with a decrease in condition index indicating that

  5. Ascorbic acid and tissue browning in pears (Pyrus communis L. cvs Rocha and Conference) under controlled atmosphere conditions

    NARCIS (Netherlands)

    Veltman, R.H.; Kho, R.M.; Schaik, van A.C.R.; Sanders, M.G.; Oosterhaven, J.

    2000-01-01

    The relationships between storage gas composition and ascorbic acid (AA) levels, and between AA levels and the development of internal browning, were studied in 'Conference' and 'Rocha' pears (Pyrus communis L.). In both cultivars, AA levels declined under (browning-inducing) controlled atmosphere

  6. Increased Tidal Dissipation Using Advanced Rheological Models: Implications for Io and Tidally Active Exoplanets

    Science.gov (United States)

    Renaud, Joe P.; Henning, Wade G.

    2018-04-01

    The advanced rheological models of Andrade and Sundberg & Cooper are compared to the traditional Maxwell model to understand how each affects the tidal dissipation of heat within rocky bodies. We find both Andrade and Sundberg–Cooper rheologies can produce at least 10× the tidal heating compared to a traditional Maxwell model for a warm (1400–1600 K) Io-like satellite. Sundberg–Cooper can cause even larger dissipation around a critical temperature and frequency. These models allow cooler planets to stay tidally active in the face of orbital perturbations—a condition we term “tidal resilience.” This has implications for the time evolution of tidally active worlds and the long-term equilibria they fall into. For instance, if Io’s interior is better modeled by the Andrade or Sundberg–Cooper rheologies, the number of possible resonance-forming scenarios that still produce a hot, modern Io is expanded, and these scenarios do not require an early formation of the Laplace resonance. The two primary empirical parameters that define the Andrade anelasticity are examined in several phase spaces to provide guidance on how their uncertainties impact tidal outcomes, as laboratory studies continue to constrain their real values. We provide detailed reference tables on the fully general equations required for others to insert the models of Andrade and Sundberg–Cooper into standard tidal formulae. Lastly, we show that advanced rheologies can greatly impact the heating of short-period exoplanets and exomoons, while the properties of tidal resilience could mean a greater number of tidally active worlds among all extrasolar systems.

  7. Novel nuances of human brown fat

    DEFF Research Database (Denmark)

    Scheele, Camilla; Larsen, Therese Juhlin; Nielsen, Søren

    2014-01-01

    the types of thermogenic adipocytes in humans. We recently published a contradictory mRNA expression signature of human supraclavicular fat defined by an upregulation of the brite marker TBX1 along with the classical brown markers ZIC1 and LHX8, as well as genes indicating brown fat activity including UCP1......, there was no difference in UCP1, PGC-1α, PRDM16, suggesting both depots had equal brown fat potency. Taken together, supraclavicular brown fat derived from adult humans seems to represent a type of brown fat with distinct features from both subcutaneous white/brite and interscapular brown fat. Therefore......There is a current debate in the literature on whether human fat derived from the supraclavicular region should be classified as brown, or as the white fat-derived less potent, brite/beige. This commentary addresses whether the existing classification defined in mice is sufficient to describe...

  8. Brown dwarfs as dark galactic halos

    International Nuclear Information System (INIS)

    Adams, F.C.; Walker, T.P.

    1990-01-01

    The possibility that the dark matter in galactic halos can consist of brown dwarf stars is considered. The radiative signature for such halos consisting solely of brown dwarfs is calculated, and the allowed range of brown dwarf masses, the initial mass function (IMF), the stellar properties, and the density distribution of the galactic halo are discussed. The prediction emission from the halo is compared with existing observations. It is found that, for any IMF of brown dwarfs below the deuterium burning limit, brown dwarf halos are consistent with observations. Brown dwarf halos cannot, however, explain the recently observed near-IR background. It is shown that future satellite missions will either detect brown dwarf halos or place tight constraints on the allowed range of the IMF. 30 refs

  9. Short period tidal variations of earth rotation

    Science.gov (United States)

    Yoder, C. F.; Williams, J. G.; Parke, M. E.; Dickey, J. O.

    1981-01-01

    It is explained that the tidal deformation of the earth's polar moment of inertia by the moon and sun cause periodic variations in rotation. The short period oscillations give rise to a meter-sized, diurnal signature in the lunar laser ranging data obtained at McDonald Observatory. A solution is given for the scale parameter k/C at fortnightly and monthly tidal frequencies. The results are compared with those obtained by other investigators and with a theoretical estimate which includes the effect of oceans and a decoupled fluid core.

  10. CFD for wind and tidal offshore turbines

    CERN Document Server

    Montlaur, Adeline

    2015-01-01

    The book encompasses novel CFD techniques to compute offshore wind and tidal applications. Computational fluid dynamics (CFD) techniques are regarded as the main design tool to explore the new engineering challenges presented by offshore wind and tidal turbines for energy generation. The difficulty and costs of undertaking experimental tests in offshore environments have increased the interest in the field of CFD which is used to design appropriate turbines and blades, understand fluid flow physical phenomena associated with offshore environments, predict power production or characterise offshore environments, amongst other topics.

  11. Tidal forces in Kiselev black hole

    Energy Technology Data Exchange (ETDEWEB)

    Shahzad, M.U. [University of Central Punjab, CAMS, UCP Business School, Lahore (Pakistan); Jawad, Abdul [COMSATS Institute of Information Technology, Department of Mathematics, Lahore (Pakistan)

    2017-06-15

    The aim of this paper is to examine the tidal forces occurring in a Kiselev black hole surrounded by radiation and dust fluids. It is noted that the radial and angular components of the tidal force change the sign between event and Cauchy horizons. We solve the geodesic deviation equation for radially free-falling bodies toward Kiselev black holes. We explain the geodesic deviation vector graphically and point out the location of the event and Cauchy horizons for specific values of the radiation and dust parameters. (orig.)

  12. NOAA Historical Tidal Current Data for the Coastal United States

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Knowledge of the timing and strength of tidal currents is extremely important for safe navigation in coastal waters. Tidal currents are almost always the strongest...

  13. Tidal flow characteristics at Kasheli (Kalwa/ Bassein creek), Bombay

    Digital Repository Service at National Institute of Oceanography (India)

    Swamy, G.N.; Suryanarayana, A.

    Tidal flow characteristics of waters at Kasheli, connected to the sea through Thane and Bassein Creeks in Bombay, Maharashtra, India are investigated based on tide and current observations carried out in 1980-81. The results establish that the tidal...

  14. Spatial tidal asymmetry of Cochin estuary, West Coast, India

    Digital Repository Service at National Institute of Oceanography (India)

    Vinita, J.; Shivaprasad, A.; Manoj, N.T.; Revichandran, C.; Naveenkumar, K.R.; Jineesh, V.K.

    tidal amplitude and currents get attenuated towards upstream through frictional dissipation The results showed that the tidal momentum balance along the main axis of the channel was dominated by pressure gradient and friction The influence of advection...

  15. Brown dwarfs and black holes

    International Nuclear Information System (INIS)

    Tarter, J.C.

    1978-01-01

    The astronomical missing-mass problem (the discrepancy between the dynamical mass estimate and the sum of individual masses in large groupings) is considered, and possible explanations are advanced. The existence of brown dwarfs (stars not massive enough to shine by nuclear burning) and black holes (extremely high density matter contraction such that gravitation allows no light emission) thus far provides the most plausible solutions

  16. Tidal propagation off the central west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Unnikrishnan, A.S.

    . [Keywords: Tidal propagation, Mumbai high, Global tidal model, Shelf model, Central west coast of India] Introduction In coastal regions, tides play an important role in determining circulation and hydrography. Barotropic tides coming from the open... with increase in the width of the shelf. Materials and Methods Global tidal models Schwiderski5 used a hydrodynamic interpolation technique to determine the amplitude and phase of tidal constituents of global ocean. Since the availability of satellite...

  17. The Mechanism of White and Brown Adipocyte Differentiation

    Directory of Open Access Journals (Sweden)

    Hironori Nakagami

    2013-04-01

    Full Text Available Obesity gives vent to many diseases such as type 2 diabetes, hypertension, and hyperlipidemia, being considered as the main causes of mortality and morbidity worldwide. The pathogenesis and pathophysiology of metabolic syndrome can well be understood by studying the molecular mechanisms that control the development and function of adipose tissue. In human body, exist two types of adipose tissue, the white and the brown one, which are reported to play various roles in energy homeostasis. The major and most efficient storage of energy occurs in the form of triglycerides in white adipose tissue while brown adipose tissue actively participates in both basal and inducible energy consumption in the form of thermogenesis. Recent years have observed a rapid and greater interest towards developmental plasticity and therapeutic potential of stromal cells those isolated from adipose tissue. The adipocyte differentiation involves a couple of regulators in the white or brown adipogenesis. Peroxisome proliferators-activated receptor-γ actively participates in regulating carbohydrate and lipid metabolism, and also acts as main regulator of both white and brown adipogenesis. This review based on our recent research, seeks to highlight the adipocyte differentiation.

  18. Morphodynamics of the Manyema Tidal Delta at Kunduchi, Tanzania

    African Journals Online (AJOL)

    Keywords: Morphodynamics, Kunduchi, Manyema, shoreline change, tidal creek, tidal delta. Abstract—The prevailing northward longshore drift of beach sand on the northern part of Msasani Bay, north of Dar es Salaam, is interrupted at Kunduchi by the tidal flushing of ... Western Indian Ocean J. Mar. Sci. Vol. 11, No. 2, pp.

  19. Field migration rates of tidal meanders recapitulate fluvial morphodynamics

    Science.gov (United States)

    Finotello, Alvise; Lanzoni, Stefano; Ghinassi, Massimiliano; Marani, Marco; Rinaldo, Andrea; D'Alpaos, Andrea

    2018-02-01

    The majority of tidal channels display marked meandering features. Despite their importance in oil-reservoir formation and tidal landscape morphology, questions remain on whether tidal-meander dynamics could be understood in terms of fluvial processes and theory. Key differences suggest otherwise, like the periodic reversal of landscape-forming tidal flows and the widely accepted empirical notion that tidal meanders are stable landscape features, in stark contrast with their migrating fluvial counterparts. On the contrary, here we show that, once properly normalized, observed migration rates of tidal and fluvial meanders are remarkably similar. Key to normalization is the role of tidal channel width that responds to the strong spatial gradients of landscape-forming flow rates and tidal prisms. We find that migration dynamics of tidal meanders agree with nonlinear theories for river meander evolution. Our results challenge the conventional view of tidal channels as stable landscape features and suggest that meandering tidal channels recapitulate many fluvial counterparts owing to large gradients of tidal prisms across meander wavelengths.

  20. How Tidal Forces Cause Ocean Tides in the Equilibrium Theory

    Science.gov (United States)

    Ng, Chiu-king

    2015-01-01

    We analyse why it is erroneous to think that a tidal bulge is formed by pulling the water surface directly up by a local vertical tidal force. In fact, ocean tides are caused by the global effect of the horizontal components of the tidal forces.

  1. Tidal exchange of larvae of Sesarma catenata (Decapoda, Brachyura)

    African Journals Online (AJOL)

    The tidal exchange of larvae of the salt-marsh grapsid crab Sesarma catenata was studied in the Swartkops estuary, a tidally driven, shallow estuary in Algoa Bay, South Africa. Plankton samples were collected bimonlhly during spring and neap tides from October to March at the tidal inlet. Samples were collected hourly for ...

  2. Tidal Marshes: The Boundary between Land and Ocean.

    Science.gov (United States)

    Gosselink, James

    An overview of the ecology of the tidal marshes along the gulf coast of the United States is presented. The following topics are included: (1) the human impact on tidal marshes; (2) the geologic origins of tidal marshes; (3) a description of the physical characteristics and ecosystem of the marshlands; (4) a description of the marshland food chain…

  3. Field migration rates of tidal meanders recapitulate fluvial morphodynamics.

    Science.gov (United States)

    Finotello, Alvise; Lanzoni, Stefano; Ghinassi, Massimiliano; Marani, Marco; Rinaldo, Andrea; D'Alpaos, Andrea

    2018-02-13

    The majority of tidal channels display marked meandering features. Despite their importance in oil-reservoir formation and tidal landscape morphology, questions remain on whether tidal-meander dynamics could be understood in terms of fluvial processes and theory. Key differences suggest otherwise, like the periodic reversal of landscape-forming tidal flows and the widely accepted empirical notion that tidal meanders are stable landscape features, in stark contrast with their migrating fluvial counterparts. On the contrary, here we show that, once properly normalized, observed migration rates of tidal and fluvial meanders are remarkably similar. Key to normalization is the role of tidal channel width that responds to the strong spatial gradients of landscape-forming flow rates and tidal prisms. We find that migration dynamics of tidal meanders agree with nonlinear theories for river meander evolution. Our results challenge the conventional view of tidal channels as stable landscape features and suggest that meandering tidal channels recapitulate many fluvial counterparts owing to large gradients of tidal prisms across meander wavelengths. Copyright © 2018 the Author(s). Published by PNAS.

  4. Salmon habitat use, tidal-fluvial estuary - Columbia River Estuary Tidal Habitats

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The goal of the tidal-fluvial estuary study is to determine the estuary's contribution to the spatial structure and life history diversity of Columbia River salmon...

  5. Empirical Tidal Dissipation in Exoplanet Hosts From Tidal Spin-up

    Science.gov (United States)

    Penev, Kaloyan; Bouma, L. G.; Winn, Joshua N.; Hartman, Joel D.

    2018-04-01

    Stars with hot Jupiters (HJs) tend to rotate faster than other stars of the same age and mass. This trend has been attributed to tidal interactions between the star and planet. A constraint on the dissipation parameter {Q}\\star {\\prime } follows from the assumption that tides have managed to spin up the star to the observed rate within the age of the system. This technique was applied previously to HATS-18 and WASP-19. Here, we analyze the sample of all 188 known HJs with an orbital period tidal dissipation parameter ({Q}\\star {\\prime }) increases sharply with forcing frequency, from 105 at 0.5 day‑1 to 107 at 2 day‑1. This helps to resolve a number of apparent discrepancies between studies of tidal dissipation in binary stars, HJs, and warm Jupiters. It may also allow for a HJ to damp the obliquity of its host star prior to being destroyed by tidal decay.

  6. 2008 NWFSC Tidal Freshwater Genetics Results

    Energy Technology Data Exchange (ETDEWEB)

    David Teel

    2009-05-01

    Genetic Analysis of Juvenile Chinook Salmon for inclusion in 'Ecology of Juvenile Salmon in Shallow Tidal Freshwater Habitats in the Vicinity of the Sandy River Delta, Lower Columbia River, 2008. Annual Report to Bonneville Power Administration, Contract DE-AC05-76RL01830.'

  7. Methane emission from tidal freshwater marshes

    NARCIS (Netherlands)

    Van der Nat, F.J.; Middelburg, J.J.

    2000-01-01

    In two tidal freshwater marshes, methane emission, production and accumulation in the pore-water have been studied. The two sites differ in their dominant vegetation, i.e., reed and bulrush, and in their heights above sea level. The reed site was elevated in relation to the bulrush site and had

  8. Estuaries and Tidal Marshes. Habitat Pac.

    Science.gov (United States)

    Fish and Wildlife Service (Dept. of Interior), Washington, DC.

    This educational packet consists of an overview, three lesson plans, student data sheets, and a poster. The overview examines estuaries and tidal or salt marshes by discussing the plants and animals in these habitats, marsh productivity, benefits and management of the habitats, historical aspects, and development and pollution. A glossary and list…

  9. Life on the Tidal Mudflats: Elkhorn Slough.

    Science.gov (United States)

    Andresen, Ruth

    Life in an estuarine environment is studied in this set of audio-visual materials prepared for grades 6-12. A 71-frame colored filmstrip, cassette tape narration, and teacher's guide focus upon Elkhorn Slough, a tidal mudflat in the Monterey Bay area, California. Topics examined range from river drainage and the effects of pollution on living…

  10. An optimal tuning strategy for tidal turbines

    Science.gov (United States)

    2016-01-01

    Tuning wind and tidal turbines is critical to maximizing their power output. Adopting a wind turbine tuning strategy of maximizing the output at any given time is shown to be an extremely poor strategy for large arrays of tidal turbines in channels. This ‘impatient-tuning strategy’ results in far lower power output, much higher structural loads and greater environmental impacts due to flow reduction than an existing ‘patient-tuning strategy’ which maximizes the power output averaged over the tidal cycle. This paper presents a ‘smart patient tuning strategy’, which can increase array output by up to 35% over the existing strategy. This smart strategy forgoes some power generation early in the half tidal cycle in order to allow stronger flows to develop later in the cycle. It extracts enough power from these stronger flows to produce more power from the cycle as a whole than the existing strategy. Surprisingly, the smart strategy can often extract more power without increasing maximum structural loads on the turbines, while also maintaining stronger flows along the channel. This paper also shows that, counterintuitively, for some tuning strategies imposing a cap on turbine power output to limit loads can increase a turbine’s average power output. PMID:27956870

  11. Palaemon pacijicus (Stimpson) in eastern Cape tidal

    African Journals Online (AJOL)

    1984-09-25

    Sep 25, 1984 ... seasonally with peak numbers and biomass found in summer ... One part of the programme dealt with the tidal pool ... pools sampled. Unicam spectrophotometer at 458 run. A dilution series was made for each batch of concentrate used. A domestic water meter was coupled to the outlet of a portable pump ...

  12. An optimal tuning strategy for tidal turbines.

    Science.gov (United States)

    Vennell, Ross

    2016-11-01

    Tuning wind and tidal turbines is critical to maximizing their power output. Adopting a wind turbine tuning strategy of maximizing the output at any given time is shown to be an extremely poor strategy for large arrays of tidal turbines in channels. This 'impatient-tuning strategy' results in far lower power output, much higher structural loads and greater environmental impacts due to flow reduction than an existing 'patient-tuning strategy' which maximizes the power output averaged over the tidal cycle. This paper presents a 'smart patient tuning strategy', which can increase array output by up to 35% over the existing strategy. This smart strategy forgoes some power generation early in the half tidal cycle in order to allow stronger flows to develop later in the cycle. It extracts enough power from these stronger flows to produce more power from the cycle as a whole than the existing strategy. Surprisingly, the smart strategy can often extract more power without increasing maximum structural loads on the turbines, while also maintaining stronger flows along the channel. This paper also shows that, counterintuitively, for some tuning strategies imposing a cap on turbine power output to limit loads can increase a turbine's average power output.

  13. Nova Scotia Power : in-stream tidal

    International Nuclear Information System (INIS)

    Meade, K.

    2007-01-01

    The Government of Nova Scotia, the Government of New Brunswick, Nova Scotia Power and others have funded a feasibility study of North American sites for commercial instream tidal power. In July 2007, Nova Scotia Power received partial funding for a demonstration project. This presentation provided information on a demonstration plant for tidal power run by Nova Scotia Power. It discussed the benefits of the Open Hydro technology for this plant. In this simple design, the generator is on the circumference of the turbine. The design does not involve any power transmission systems or any pitching of blades. In addition, the technology is environmentally sound as it is completely shrouded, has low rotational speed, and a large open centre allows fish to pass through, and it does not require lubricants. The last benefit that was presented was the scale up of 250 kW machine deployed in a European test facility. The presentation also discussed the advantages of developing tidal power at this time. It was concluded that tidal energy has significant potential. Although it is intermittent, it is predictable and bulk power system can be scheduled to accommodate it. figs

  14. The history of tidal power in France

    International Nuclear Information System (INIS)

    Banal, M.

    1997-01-01

    The first known use of tidal power in France concerns the tidal mills in general use during the Middle Age along the French coasts. The first research studies of tidal power plants started at the end of the first world war but it is only in 1940 with the stimulus of Robert Gibrat that was created the Research Society for the use of Tides and the Rance plant project. In 1946, Electricite de France (EdF) started again the studies of this company for a greater size project in the Chausey archipelago which was abandoned for the benefit of the Rance project in the 1960's. The start up of the plant took place in 1967 but the other projects were abandoned during the 1980's. This short paper recalls the historical aspects of the development of tidal power in France and focusses on the research and development studies and on the economical, political and legal factors that led to retain the Rance project among others proposed. (J.S.)

  15. Carbon sequestration by Australian tidal marshes

    KAUST Repository

    Macreadie, Peter I.; Ollivier, Q. R.; Kelleway, J. J.; Serrano, O.; Carnell, P. E.; Lewis, C. J. Ewers; Atwood, T. B.; Sanderman, J.; Baldock, J.; Connolly, R. M.; Duarte, Carlos M.; Lavery, P. S.; Steven, A.; Lovelock, C. E.

    2017-01-01

    ) storage in Australia's tidal marshes (323 cores). OC stocks in the surface 1 m averaged 165.41 (SE 6.96) Mg OC ha-1 (range 14-963 Mg OC ha-1). The mean OC accumulation rate was 0.55 ± 0.02 Mg OC ha-1 yr-1. Geomorphology was the most important predictor

  16. Tidal asymmetry in a funnel-shaped estuary with mixed semidiurnal tides

    Science.gov (United States)

    Gong, Wenping; Schuttelaars, Henk; Zhang, Heng

    2016-05-01

    results show that the FDA exhibits a predominant tendency of shorter duration of low water slack, favoring the landward transport of fine sediment. The FVA demonstrates prevailing ebb dominance in the study period, favoring the seaward transport of coarse sediment. This ebb dominance is primarily induced by the interaction among the residual flow and the tidal constituents. The external TDA in the ocean experiences distinct cyclic variations with positive asymmetry when semidiurnal tides dominate and negative asymmetry during the periods when diurnal tides dominate. The funnel shape of the HE is advantageous for the development of positive tidal asymmetry as the semidiurnal tides are more amplified than the diurnal tides. The effect of river flow can enhance the ebb dominance, while the baroclinic effect is more complex. The existence of channel and shoals favors the development of residual pattern with seaward flow (ebb dominance) in the channel and landward flow (flood dominance) at the shoal when the tides are strong (semidiurnal tides dominate) and the residual pattern with landward flow (flood dominance) in the channel and seaward flow (ebb dominance) at the shoal when the baroclinic effect is dominant (diurnal tides dominate).

  17. Phase lag control of tidally reversing mega-ripple geometry and bed stress in tidal inlets

    Science.gov (United States)

    Traykovski, P.

    2016-02-01

    Recent observations in the Columbia River Mouth, New River Inlet, and Wasque Shoals have shown that tidally reversing mega-ripples are an ubiquitous bedform morphology in energetic tidal inlets. As the name implies, these bedforms reverse asymmetry and migration direction in each half tidal cycle. With wavelengths of 2 to 5 m and heights of 0.2 to 0.5 m, these bedforms are larger than current formed ripples, but smaller than dunes. Unlike dunes which have a depth dependent geometry, observations indicate the tidally reversing mega-ripples geometry is related to the time dependent tidal flow and independent of depth. Previous empirical relations for predicting the geometry of ripples or dunes do not successfully predict the geometry of these features. A time dependent geometric model was developed that accounts for the reversal of migration and asymmetry to successfully predict bedform geometry. The model requires sufficient sediment transport in each half tidal cycle to reverse the asymmetry before the bedforms begin to grow. Both the observations and model indicate that the complete reversal of asymmetry and development of a steep lee face occurs near or after maximum flow in each half tidal cycle. This phase lag in bedform response to tidal forcing also has important implications for bed stress in tidal inlets. Observations of frictional drag in the Columbia River mouth based on a tidal momentum balance of surface slope over 10 km regressed against quadratic near bed velocity show drag coefficients that fall off as CD U-1.4. Reynolds stress measurements performed using the dual ADV differencing technique show similar relations. The Reynolds stress measurements also show a dramatic asymmetry between accelerating flows and decelerating flows with a factor of 5 increase during deceleration. Pulse coherent Doppler profiles of near bed turbulence indicate that the turbulence is dominated by energetic fluctuations in separation zones downstream of steep lee faces. The

  18. TIDAL EVOLUTION OF CLOSE-IN PLANETS

    International Nuclear Information System (INIS)

    Matsumura, Soko; Rasio, Frederic A.; Peale, Stanton J.

    2010-01-01

    Recent discoveries of several transiting planets with clearly non-zero eccentricities and some large obliquities started changing the simple picture of close-in planets having circular and well-aligned orbits. The two major scenarios that form such close-in planets are planet migration in a disk and planet-planet interactions combined with tidal dissipation. The former scenario can naturally produce a circular and low-obliquity orbit, while the latter implicitly assumes an initially highly eccentric and possibly high-obliquity orbit, which are then circularized and aligned via tidal dissipation. Most of these close-in planets experience orbital decay all the way to the Roche limit as previous studies showed. We investigate the tidal evolution of transiting planets on eccentric orbits, and find that there are two characteristic evolution paths for them, depending on the relative efficiency of tidal dissipation inside the star and the planet. Our study shows that each of these paths may correspond to migration and scattering scenarios. We further point out that the current observations may be consistent with the scattering scenario, where the circularization of an initially eccentric orbit occurs before the orbital decay primarily due to tidal dissipation in the planet, while the alignment of the stellar spin and orbit normal occurs on a similar timescale to the orbital decay largely due to dissipation in the star. We also find that even when the stellar spin-orbit misalignment is observed to be small at present, some systems could have had a highly misaligned orbit in the past, if their evolution is dominated by tidal dissipation in the star. Finally, we also re-examine the recent claim by Levrard et al. that all orbital and spin parameters, including eccentricity and stellar obliquity, evolve on a similar timescale to orbital decay. This counterintuitive result turns out to have been caused by a typo in their numerical code. Solving the correct set of tidal

  19. Protoplanetary disc response to distant tidal encounters in stellar clusters

    Science.gov (United States)

    Winter, A. J.; Clarke, C. J.; Rosotti, G.; Booth, R. A.

    2018-04-01

    The majority of stars form in a clustered environment. This has an impact on the evolution of surrounding protoplanetary discs (PPDs) due to either photoevaporation or tidal truncation. Consequently, the development of planets depends on formation environment. Here, we present the first thorough investigation of tidally induced angular momentum loss in PPDs in the distant regime, partly motivated by claims in the literature for the importance of distant encounters in disc evolution. We employ both theoretical predictions and dynamical/hydrodynamical simulations in 2D and 3D. Our theoretical analysis is based on that of Ostriker (1994) and leads us to conclude that in the limit that the closest approach distance xmin ≫ r, the radius of a particle ring, the fractional change in angular momentum scales as (xmin/r)-5. This asymptotic limit ensures that the cumulative effect of distant encounters is minor in terms of its influence on disc evolution. The angular momentum transfer is dominated by the m = 2 Lindblad resonance for closer encounters and by the m = 1, ω = 0 Lindblad resonance at large xmin/r. We contextualize these results by comparing expected angular momentum loss for the outer edge of a PPD due to distant and close encounters. Contrary to the suggestions of previous works, we do not find that distant encounters contribute significantly to angular momentum loss in PPDs. We define an upper limit for closest approach distance where interactions are significant as a function of arbitrary host to perturber mass ratio M2/M1.

  20. Tidal origin of NGC 1427A in the Fornax cluster

    Science.gov (United States)

    Lee-Waddell, K.; Serra, P.; Koribalski, B.; Venhola, A.; Iodice, E.; Catinella, B.; Cortese, L.; Peletier, R.; Popping, A.; Keenan, O.; Capaccioli, M.

    2018-02-01

    We present new HI observations from the Australia Telescope Compact Array and deep optical imaging from OmegaCam on the VLT Survey Telescope of NGC 1427A, an arrow-shaped dwarf irregular galaxy located in the Fornax cluster. The data reveal a star-less HI tail that contains ˜10 per cent of the atomic gas of NGC 1427A as well as extended stellar emission that shed new light on the recent history of this galaxy. Rather than being the result of ram pressure induced star formation, as previously suggested in the literature, the disturbed optical appearance of NGC 1427A has tidal origins. The galaxy itself likely consists of two individual objects in an advanced stage of merging. The HI tail may be made of gas expelled to large radii during the same tidal interaction. It is possible that some of this gas is subject to ram pressure, which would be considered a secondary effect and implies a north-west trajectory of NGC 1427A within the Fornax cluster.

  1. Light rays and the tidal gravitational pendulum

    Science.gov (United States)

    Farley, A. N. St J.

    2018-05-01

    Null geodesic deviation in classical general relativity is expressed in terms of a scalar function, defined as the invariant magnitude of the connecting vector between neighbouring light rays in a null geodesic congruence projected onto a two-dimensional screen space orthogonal to the rays, where λ is an affine parameter along the rays. We demonstrate that η satisfies a harmonic oscillator-like equation with a λ-dependent frequency, which comprises terms accounting for local matter affecting the congruence and tidal gravitational effects from distant matter or gravitational waves passing through the congruence, represented by the amplitude, of a complex Weyl driving term. Oscillating solutions for η imply the presence of conjugate or focal points along the rays. A polarisation angle, is introduced comprising the orientation of the connecting vector on the screen space and the phase, of the Weyl driving term. Interpreting β as the polarisation of a gravitational wave encountering the light rays, we consider linearly polarised waves in the first instance. A highly non-linear, second-order ordinary differential equation, (the tidal pendulum equation), is then derived, so-called due to its analogy with the equation describing a non-linear, variable-length pendulum oscillating under gravity. The variable pendulum length is represented by the connecting vector magnitude, whilst the acceleration due to gravity in the familiar pendulum formulation is effectively replaced by . A tidal torque interpretation is also developed, where the torque is expressed as a coupling between the moment of inertia of the pendulum and the tidal gravitational field. Precessional effects are briefly discussed. A solution to the tidal pendulum equation in terms of familiar gravitational lensing variables is presented. The potential emergence of chaos in general relativity is discussed in the context of circularly, elliptically or randomly polarised gravitational waves encountering the null

  2. Flow paths of water and sediment in a tidal marsh: relations with marsh developmental stage and tidal inundation height

    NARCIS (Netherlands)

    Temmerman, S.; Bouma, T.J.; Govers, G.; Lauwaet, D.

    2005-01-01

    This study provides new insights in the relative role of tidal creeks and the marsh edge in supplying water and sediments to and from tidal marshes for a wide range of tidal inundation cycles with different high water levels and for marsh zones of different developmental stage. Net import or export

  3. Earth Tidal Controls on Basal Dynamics and Hydrology

    Science.gov (United States)

    Kulessa, B.; Hubbard, B. P.; Brown, G. H.; Becker, J.

    2001-12-01

    We appraise earth tidal forcing of coupled mechanical and hydrological processes beneath warm-based ice masses, which have to date been poorly documented but represent exciting phenomena that have important implications for future studies of glacier dynamics. Regular cycles in winter and early spring electrical self-potential (SP), water pressure (PW) and electrical conductivity (EC) were recorded at the bases of several boreholes drilled through Haut Glacier d'Arolla, Switzerland. Fourier power spectra of these data reflect the presence of diurnal and semi-diurnal cycles, and comparison with the earth tidal spectrum indicates that at least four components of the latter are visible in the borehole spectra: the luni-solar diurnal, the principal lunar diurnal, the principal solar semi-diurnal, and the principal lunar semi-diurnal. This correspondence suggests that earth tides exert a strong control over water flow at the bed of the glacier, at least during winter and early spring. We envisage a mechanism that involves earth-tide induced deformation of the bedrock and the unconsolidated sediments beneath the glacier, and to a certain extent probably also the overlying ice body. Basal water pockets, including those containing our sensors, located within these media are in turn also likely to be deformed periodically. We believe that PW gradients induced by such deformation may result in transient water flow and SPs in the pockets. Since PW and EC are typically out-of-phase, injection of waters of lower EC into the pockets during times of peak water flow is likely. Several lines of evidence suggest that such injection was caused by melting of the ice wall due to frictional heating, balancing creep closure which sustained some pockets through the winter. Further, the first annually-repeated post-winter reorganization event, termed the May event, may well be triggered by tidally-induced releases of waters from storage. This implies that the May event marks the opening of

  4. Tidal Love numbers and moment-Love relations of polytropic stars

    Science.gov (United States)

    Yip, Kenny L. S.; Leung, P. T.

    2017-12-01

    The physical significance of tidal deformation in astronomical systems has long been known. The recently discovered universal I-Love-Q relations, which connect moment of inertia, quadrupole tidal Love number and spin-induced quadrupole moment of compact stars, also underscore the special role of tidal deformation in gravitational wave astronomy. Motivated by the observation that such relations also prevail in Newtonian stars and crucially depend on the stiffness of a star, we consider the tidal Love numbers of Newtonian polytropic stars whose stiffness is characterized by a polytropic index n. We first perturbatively solve the Lane-Emden equation governing the profile of polytropic stars through the application of the scaled delta expansion method and then formulate perturbation series for the multipolar tidal Love number about the two exactly solvable cases with n = 0 and n = 1, respectively. Making use of these two series to form a two-point Padé approximant, we find an approximate expression of the quadrupole tidal Love number, whose error is less than 2.5 × 10-5 per cent (0.39 per cent) for n ∈ [0, 1] (n ∈ [0, 3]). Similarly, we also determine the mass moments for polytropic stars accurately. Based on these findings, we are able to show that the I-Love-Q relations are in general stationary about the incompressible limit irrespective of the equation of state of a star. Moreover, for the I-Love-Q relations, there is a secondary stationary point near n ≈ 0.4444, thus showing the insensitivity to n for n ∈ [0, 1]. Our investigation clearly tracks the universality of the I-Love-Q relations from their validity for stiff stars such as neutron stars to their breakdown for soft stars.

  5. Tidal volume in acute respiratory distress syndrome: how best to select it.

    Science.gov (United States)

    Umbrello, Michele; Marino, Antonella; Chiumello, Davide

    2017-07-01

    Mechanical ventilation is the type of organ support most widely provided in the intensive care unit. However, this form of support does not constitute a cure for acute respiratory distress syndrome (ARDS), as it mainly works by buying time for the lungs to heal while contributing to the maintenance of vital gas exchange. Moreover, it can further damage the lung, leading to the development of a particular form of lung injury named ventilator-induced lung injury (VILI). Experimental evidence accumulated over the last 30 years highlighted the factors associated with an injurious form of mechanical ventilation. The present paper illustrates the physiological effects of delivering a tidal volume to the lungs of patients with ARDS, and suggests an approach to tidal volume selection. The relationship between tidal volume and the development of VILI, the so called volotrauma, will be reviewed. The still actual suggestion of a lung-protective ventilatory strategy based on the use of low tidal volumes scaled to the predicted body weight (PBW) will be presented, together with newer strategies such as the use of airway driving pressure as a surrogate for the amount of ventilatable lung tissue or the concept of strain, i.e., the ratio between the tidal volume delivered relative to the resting condition, that is the functional residual capacity (FRC). An ultra-low tidal volume strategy with the use of extracorporeal carbon dioxide removal (ECCO 2 R) will be presented and discussed. Eventually, the role of other ventilator-related parameters in the generation of VILI will be considered (namely, plateau pressure, airway driving pressure, respiratory rate (RR), inspiratory flow), and the promising unifying framework of mechanical power will be presented.

  6. Mining CANDELS for Tidal Features to Constrain Major Merging During Cosmic Noon

    Science.gov (United States)

    McIntosh, Daniel H.; Mantha, Kameswara; Ciaschi, Cody; Evan, Rubyet A.; Fries, Logan B.; Landry, Luther; Thompson, Scott E.; Snyder, Gregory; Guo, Yicheng; Ceverino, Daniel; Häuβler, Boris; Primack, Joel; Simons, Raymond C.; Zheng, Xianzhong; Cosmic Assembly Near-Infrared Deep Extragalactic Legacy Survey (CANDELS) Team

    2018-01-01

    The role of major merging in the rapid buildup and development of massive galaxies at z>1 remains an open question. New theories and observations suggest that non-merging processes like violent disk instabilities may be more vital than previously thought at assembling bulges, producing clumps, and inducing morphological disturbances that may be misinterpreted as the product of major merging. We will present initial results on a systematic search for hallmark tidal indicators of major merging in a complete sample of nearly 6000 massive z>1 galaxies from CANDELS (Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey), the premiere HST/WFC3 Treasury program. We have visually inspected published GALFIT F160W residual (image-model) maps and produced a comprehensive new catalog of Sersic residual characteristics based on a variety of natural features and poor-fit artifacts. Using this catalog, we find the frequency of galaxies with tidal signatures is very small in CANDELS data. Accounting for the brief time scale associated with faint transient tidal features, our preliminary finding indicates that merger fractions derived from the CANDELS morphological classification efforts are substantially overestimated. We are using the database of residual classifications as a baseline to (1) produce improved multi-component residual maps using GALFIT_M, (2) automatically extract and quantify plausible tidal indicators and substructures (clumps vs. multiple nuclei), (3) develop a new deep-learning classification pipeline to robustly identify merger indicators in imaging data, and (4) inform the systematic analyses of synthetic mock (CANDELized) images from zoom-in hydrodynamic simulations to thoroughly quantify the impacts of cosmological dimming, and calibrate the observability timescale of tidal feature detections. Our study will ultimately yield novel constraints on merger rates at z>1 and a definitive census of massive high-noon galaxies with tidal and double

  7. Toxins not neutralized by brown snake antivenom

    International Nuclear Information System (INIS)

    Judge, Roopwant K.; Henry, Peter J.; Mirtschin, Peter; Jelinek, George; Wilce, Jacqueline A.

    2006-01-01

    The Australian snakes of the genus Pseudonaja (dugite, gwardar and common brown) account for the majority of snake bite related deaths in Australia. Without antivenom treatment, the risk of mortality is significant. There is an accumulating body of evidence to suggest that the efficacy of the antivenom is limited. The current study investigates the protein constituents recognized by the antivenom using 2-DE, immuno-blot techniques and rat tracheal organ bath assays. The 2-DE profiles for all three snake venoms were similar, with major species visualized at 78-132 kDa, 32-45 kDa and 6-15 kDa. Proteins characterized by LC-MS/MS revealed a coagulant toxin (∼42 kDa) and coagulant peptide (∼6 kDa), as well as two PLA 2 (∼14 kDa). Peptides isolated from ∼78 kDa and 15-32 kDa protein components showed no similarity to known protein sequences. Protein recognition by the antivenom occurred predominantly for the higher molecular weight components with little recognition of 6-32 kDa MW species. The ability of antivenom to neutralize venom activity was also investigated using rat tracheal organ bath assays. The venoms of Pseudonaja affinis affinis and Pseudonaja nuchalis incited a sustained, significant contraction of the trachea. These contractions were attributed to PLA 2 enzymatic activity as pre-treatment with the PLA 2 inhibitor 4-BPB attenuated the venom-induced contractions. The venom of Pseudonaja textilis incited tracheal contractility through a non-PLA 2 enzymatic activity. Neither activity was attenuated by the antivenom treatment. These results represent the first proteomic investigation of the venoms from the snakes of the genus Pseudonaja, revealing a possible limitation of the brown snake antivenom in binding to the low MW protein components

  8. Tidal regimes and salt marshes - the River Hamble analogue

    International Nuclear Information System (INIS)

    Gray, A.J.; Moy, I.L.; Warman, E.A.; Dawson, F.H.; Henville, P.

    1993-01-01

    Construction of estuarine tidal-energy barrages has a potentially major effect on the tidal regime of the estuary, particularly upstream of a barrage. Because tidal regime largely controls the distribution and species composition of intertidal plant and animal communities, it is important to understand how barrages may affect such communities. The main objectives of the research described in this report were to relate recent changes in tidal regime within an embanked area of salt marsh and mudflat to changes in the distribution of plant species. This was to test predictions about tidal control of species' range and to assess the site's suitability as an analogue of post-barrage conditions. (author)

  9. Pressure-gradient-driven nearshore circulation on a beach influenced by a large inlet-tidal shoal system

    Science.gov (United States)

    Shi, F.; Hanes, D.M.; Kirby, J.T.; Erikson, L.; Barnard, P.; Eshleman, J.

    2011-01-01

    The nearshore circulation induced by a focused pattern of surface gravity waves is studied at a beach adjacent to a major inlet with a large ebb tidal shoal. Using a coupled wave and wave-averaged nearshore circulation model, it is found that the nearshore circulation is significantly affected by the heterogeneous wave patterns caused by wave refraction over the ebb tidal shoal. The model is used to predict waves and currents during field experiments conducted near the mouth of San Francisco Bay and nearby Ocean Beach. The field measurements indicate strong spatial variations in current magnitude and direction and in wave height and direction along Ocean Beach and across the ebb tidal shoal. Numerical simulations suggest that wave refraction over the ebb tidal shoal causes wave focusing toward a narrow region at Ocean Beach. Due to the resulting spatial variation in nearshore wave height, wave-induced setup exhibits a strong alongshore nonuniformity, resulting in a dramatic change in the pressure field compared to a simulation with only tidal forcing. The analysis of momentum balances inside the surf zone shows that, under wave conditions with intensive wave focusing, the alongshore pressure gradient associated with alongshore nonuniform wave setup can be a dominant force driving circulation, inducing heterogeneous alongshore currents. Pressure-gradient- forced alongshore currents can exhibit flow reversals and flow convergence or divergence, in contrast to the uniform alongshore currents typically caused by tides or homogeneous waves.

  10. Tidal disruption of fuzzy dark matter subhalo cores

    Science.gov (United States)

    Du, Xiaolong; Schwabe, Bodo; Niemeyer, Jens C.; Bürger, David

    2018-03-01

    We study tidal stripping of fuzzy dark matter (FDM) subhalo cores using simulations of the Schrödinger-Poisson equations and analyze the dynamics of tidal disruption, highlighting the differences with standard cold dark matter. Mass loss outside of the tidal radius forces the core to relax into a less compact configuration, lowering the tidal radius. As the characteristic radius of a solitonic core scales inversely with its mass, tidal stripping results in a runaway effect and rapid tidal disruption of the core once its central density drops below 4.5 times the average density of the host within the orbital radius. Additionally, we find that the core is deformed into a tidally locked ellipsoid with increasing eccentricities until it is completely disrupted. Using the core mass loss rate, we compute the minimum mass of cores that can survive several orbits for different FDM particle masses and compare it with observed masses of satellite galaxies in the Milky Way.

  11. Systemic control of brown fat thermogenesis: integration of peripheral and central signals.

    Science.gov (United States)

    Schulz, Tim J; Tseng, Yu-Hua

    2013-10-01

    Brown adipose tissue (BAT) is of great scientific interest as a potential target to treat obesity. The development of novel strategies to quantify brown fat thermogenesis in adult humans now enables minimally invasive assessment of novel pharmacotherapeutics. Input from the central nervous system via sympathetic efferents is widely regarded as the key controller of BAT-mediated thermogenesis in response to changes in body temperature or nutrient availability. More recently, however, it has become clear that locally secreted signals and endocrine factors originating from multiple organs can control the recruitment of brown adipocytes and, more importantly, induce thermogenesis in brown fat. Thus, they provide an attractive strategy to fine-tune brown fat thermogenesis independent of classical temperature sensing. Here, we summarize recent findings on bone morphogenetic protein signaling as an example of secreted factors in the regulation of brown adipocyte formation and systemic control of energy metabolism. We further highlight endocrine communication routes between the different types of brown adipocytes and other organs that contribute to regulation of thermogenesis. Thus, emerging evidence suggests that the classical mechanisms of central temperature sensing and sympathetic nervous system-driven thermogenesis are complemented by local and endocrine signals to determine systemic energy homeostasis. © 2013 New York Academy of Sciences.

  12. Tidal Friction in the Earth and Ocean

    Science.gov (United States)

    Ray, R. D.

    2006-12-01

    "Tidal Friction" is a classic subject in geophysics, with ties to some of the great scientists of the Victorian era. The subject has been reinvigorated over the past decade by space geodesy, and particularly by the Topex/Poseidon satellite altimeter mission. In fact, the topic has now taken on some significance in oceanography, with potential implications for problems of mixing, thermocline maintenance, and the thermohaline circulation. Likewise, tidal measurements have become sufficiently precise to reveal new information about the solid earth. In this respect, the tidal force is an invaluable "probe" of the earth, at frequencies well outside the seismic band. This talk will "follow the energy" of tides while noting some important geophysical implications at each stage. In the present earth-moon-sun configuration, energy for tides is extracted from the earth's rotation. Ancient eclipses bear witness to this, and the discrepancy between Babylonian (and other) observations and tidal predictions yields unique information about the mantle and the overlying fluid envelope. Complementary information comes from tidal anelasticity estimates, which are now available at frequencies ranging from semidiurnal to fortnightly, monthly, and 18.6 years. These data, when combined with various kinds of gravity measurements, are relevant to the present-day sea-level problem. Solid-earth tidal dissipation represents less than 5% of the system total. As has long been realized, the largest energy sink is the ocean. About 70% of the oceanic dissipation occurs in shallow seas (the traditional sink) and 30% in the deep ocean, generally near rugged bottom topography. The latter represents a substantial amount of power, roughly 1 gigawatt, available for generation of internal tides and other baroclinic motions. Experiments like HOME are helping unravel the links between barotropic tides, internal tides, turbulence, and mixing. The latter opens possible linkages to climate, and recent work

  13. Enzymatic Browning: a practical class

    Directory of Open Access Journals (Sweden)

    Maria Teresa Pedrosa Silva Clerici

    2014-10-01

    Full Text Available This paper presents a practical class about the enzymes polyphenol oxidases, which have been shown to be responsible for the enzymatic browning of fruits and vegetables. Vegetables samples were submitted to enzymatic inactivation process with chemical reagents, as well as by bleaching methods of applying heat by conventional oven and microwave oven. Process efficiency was assessed qualitatively by both observing the guaiacol peroxidase activity and after the storage period under refrigeration or freezing. The practical results obtained in this class allow exploring multidisciplinary knowledge in food science, with practical applications in everyday life.

  14. Tidal power dams in the Bay of Fundy

    International Nuclear Information System (INIS)

    Walsun, W. van

    1998-01-01

    The challenges of harnessing tidal power and the construction of dams and tidal power plants in a tidal-ocean environment such as the Bay of Fundy in New Brunswick are discussed. In the 1966-1988 series of studies, three sites were chosen at the Bay of Fundy as being the most promising, namely (1) site B9 in Minas Basin at the entrance to Cobequid Bay, (2) site A8 at the narrow neck beyond the entrance to Cumberland Basin, and (3) site A6 at the entrance to Shepody Bay. All the sites are located at the head of the Bay of Fundy because that is where the maximum tidal ranges are found and a basin's tidal energy potential is proportional to the square of its tidal range. Site B9 was determined to have the greatest tidal power potential but no plant has ever been built because reports have stated that a solid conventional tidal power barrage at site B9 would increase the tidal range at Boston by as much as 30 cm. Rather than abandoning the site for this reason, an installation consisting of a series of piers from shore to shore with hydraulic turbines mounted in the spaces between piers, was suggested. A simple mathematical model has been developed for determining the operation of this tidal fence. The cost of energy, generated by the tidal fence at site B9 was also calculated. Further studies are suggested to determine the exact environmental effect of the tidal fence on the tidal regime. If environmental problems persist, machines with larger discharge capabilities could be considered to reduce the interference of the fence with natural tidal movements. 9 refs., 6 figs

  15. Role of ascorbic acid in the inhibition of polyphenol oxidase and the prevention of browning in different browning-sensitive Lactuca sativa var. capitata (L.) and Eruca sativa (Mill.) stored as fresh-cut produce.

    Science.gov (United States)

    Landi, Marco; Degl'Innocenti, Elena; Guglielminetti, Lorenzo; Guidi, Lucia

    2013-06-01

    Polyphenol oxidase (PPO) and, to a minor extent, peroxidase (POD) represent the key enzymes involved in enzymatic browning, a negative process induced by cutting fresh-cut produce such as lettuce (Lactuca sativa) and rocket salad (Eruca sativa). Although ascorbic acid is frequently utilised as an anti-browning agent, its mechanism in the prevention of the browning phenomenon is not clearly understood. The activity of PPO and POD and their isoforms in lettuce (a high-browning and low-ascorbic acid species) and rocket salad (a low-browning and high-ascorbic species) was characterised. The kinetic parameters of PPO and in vitro ascorbic acid-PPO inhibition were also investigated. In rocket salad, PPO activity was much lower than that in lettuce and cutting induced an increase in PPO activity only in lettuce. Exogenous ascorbic acid (5 mmol L(-1)) reduced PPO activity by about 90% in lettuce. POD did not appear to be closely related to browning in lettuce. PPO is the main enzyme involved in the browning phenomenon; POD appears to play a minor role. The concentration of endogenous ascorbic acid in rocket salad was related to its low-browning sensitivity after cutting. In lettuce, the addition of ascorbic acid directly inhibited PPO activity. The results suggest that the high ascorbic acid content found in rocket salad plays an effective role in reducing PPO activity. © 2012 Society of Chemical Industry.

  16. The contact allergen dinitrochlorobenzene (DNCB) and respiratory allergy in the Th2-prone Brown Norway rat

    NARCIS (Netherlands)

    Kuper, C.F.; Stierum, R.H.; Boorsma, A.; Schijf, M.A.; Prinsen, M.; Bruijntjes, J.P.; Bloksma, N.; Arts, J.H.E.

    2008-01-01

    All LMW respiratory allergens known to date can also induce skin allergy in test animals. The question here was if in turn skin allergens can induce allergy in the respiratory tract. Respiratory allergy was tested in Th2-prone Brown Norway (BN) rats by dermal sensitization with the contact allergen

  17. Ecology of tidal freshwater forests in coastal deltaic Louisiana and northeastern South Carolina: Chapter 9

    Science.gov (United States)

    Conner, William H.; Krauss, Ken W.; Doyle, Thomas W.

    2007-01-01

    Tidal freshwater swamps in the southeastern United States are subjected to tidal hydroperiods ranging in amplitude from microtidal (forests, scrub-shrub stands, marsh, or open water but are less likely to convert mesotidal swamps. Changes to hydrological patterns tend to be more noticeable in Louisiana than do those in South Carolina.The majority of Louisiana’s coastal wetland forests are found in the Mississippi River deltaic plain region. Coastal wetland forests in the deltaic plain have been shaped by the sediments, water, and energy of the Mississippi River and its major distributaries. Baldcypress (Taxodium distichum [L.] L.C. Rich.) and water tupelo (Nyssa aquatica L.) are the primary tree species in the coastal swamp forests of Louisiana. Sites where these species grow usually hold water for most of the year; however, some of the more seaward sites were historically microtidal, especially where baldcypress currently dominates. In many other locations, baldcypress and water tupelo typically grow in more or less pure stands or as mixtures of the two with common associates such as black willow (Salix nigra Marsh.), red maple (Acer rubrum L.), water locust (Gleditsia aquatic Marsh.), overcup oak (Quercus lyrata Walt.), water hickory (Carya aquatica [Michx. f.] Nutt.), green ash (Fraxinus pennsylvanica Marsh.), pumpkin ash (F. profunda Bush.), and redbay (Persea borbonia [L.] Sprengel) (Brown and Montz 1986).The South Carolina coastal plain occupies about two-thirds of the state and rises gently to 150 m from the Atlantic Ocean up to the Piedmont plateau. Many rivers can be found in the Coastal Plain with swamps near the coast that extend inland along the rivers. Strongly tidal freshwater forests occur along the lower reaches of redwater rivers (Santee, Great Pee Dee, and Savannah) that arise in the mountains and along the numerous blackwater rivers (Ashepoo, Combahee, Cooper, and Waccamaw) that arise in the coastal regions. Most of the tidal freshwater forests

  18. Experiments on topographies lacking tidal conversion

    Science.gov (United States)

    Maas, Leo; Paci, Alexandre; Yuan, Bing

    2015-11-01

    In a stratified sea, internal tides are supposedly generated when the tide passes over irregular topography. It has been shown that for any given frequency in the internal wave band there are an infinite number of exceptions to this rule of thumb. This ``stealth-like'' property of the topography is due to a subtle annihilation of the internal waves generated during the surface tide's passage over the irregular bottom. We here demonstrate this in a lab-experiment. However, for any such topography, subsequently changing the surface tide's frequency does lead to tidal conversion. The upshot of this is that a tidal wave passing over an irregular bottom is for a substantial part trapped to this irregularity, and only partly converted into freely propagating internal tides. Financially supported by the European Community's 7th Framework Programme HYDRALAB IV.

  19. Power Generation for River and Tidal Generators

    Energy Technology Data Exchange (ETDEWEB)

    Muljadi, Eduard [National Renewable Energy Lab. (NREL), Golden, CO (United States); Wright, Alan [National Renewable Energy Lab. (NREL), Golden, CO (United States); Gevorgian, Vahan [National Renewable Energy Lab. (NREL), Golden, CO (United States); Donegan, James [Ocean Renewable Power Company (ORPC), Portland, ME (United States); Marnagh, Cian [Ocean Renewable Power Company (ORPC), Portland, ME (United States); McEntee, Jarlath [Ocean Renewable Power Company (ORPC), Portland, ME (United States)

    2016-06-01

    Renewable energy sources are the second largest contributor to global electricity production, after fossil fuels. The integration of renewable energy continued to grow in 2014 against a backdrop of increasing global energy consumption and a dramatic decline in oil prices during the second half of the year. As renewable generation has become less expensive during recent decades, and it becomes more accepted by the global population, the focus on renewable generation has expanded from primarily wind and solar to include new types with promising future applications, such as hydropower generation, including river and tidal generation. Today, hydropower is considered one of the most important renewable energy sources. In river and tidal generation, the input resource flow is slower but also steadier than it is in wind or solar generation, yet the level of water turbulent flow may vary from one place to another. This report focuses on hydrokinetic power conversion.

  20. Tidal Disruption Events from Eccentric Nuclear Disks

    Science.gov (United States)

    Wernke, Heather N.; Madigan, Ann-Marie

    2018-04-01

    Stars that get too close to a supermassive black hole are in danger of being tidally disrupted. Stellar two-body relaxation is commonly assumed to be the main driver of these events. Recent work has shown, however, that secular gravitational torques from eccentric nuclear disks can push stars to extreme eccentricities at much higher rates than predicted by two-body relaxation. This work did not include the effects of general relativity, however, which could quench secular torques via rapid apsidal precession. Here we show that, for a star in danger of disruption, general relativity acts on a timescale of less than an orbital period. This short timescale means that general relativity does not have enough time to have a major effect on the orbit. When driven by secular torques from eccentric nuclear disks, tidal disruption event rates are not affected by general relativity.

  1. Characterizing Water Ice Clouds on the Coldest Known Brown Dwarf

    Science.gov (United States)

    Luhman, Kevin; Burgasser, Adam; Cushing, Michael; Esplin, Taran; Fortney, Jonathan; Hardegree-Ullman, Kevin; Marley, Mark; Morley, Caroline; Schneider, Adam; Trucks, Jesica

    2014-12-01

    We have conducted a search for high proper motion brown dwarfs using multi-epoch all-sky mid-infrared images from the WISE satellite. Through this work, we have discovered an object with a parallactic distance of 2.3 pc and a temperature of 250 K, making it the 4th closest neighbor of the Sun, and the coldest known brown dwarf. Because of its extreme proximity and temperature, it represents an unparalleled laboratory for studying planet-like atmospheres in an unexplored temperature regime. We propose to photometrically monitor this object with IRAC to 1) detect and characterize water ice clouds in its atmosphere via the short-term variations induced during rotation and 2) constrain the long-term evolution of its clouds across a period of months.

  2. Brown dwarf disks with ALMA

    Energy Technology Data Exchange (ETDEWEB)

    Ricci, L.; Isella, A. [Department of Astronomy, California Institute of Technology, MC 249-17, Pasadena, CA 91125 (United States); Testi, L.; De Gregorio-Monsalvo, I. [European Southern Observatory, Karl-Schwarzschild-Strasse 2, D-85748 Garching (Germany); Natta, A. [INAF-Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, I-50125 Firenze (Italy); Scholz, A., E-mail: lricci@astro.caltech.edu [School of Cosmic Physics, Dublin Institute for Advanced Studies, 31 Fitzwilliam Place, Dublin 2 (Ireland)

    2014-08-10

    We present Atacama Large Millimeter/submillimeter Array continuum and spectral line data at 0.89 mm and 3.2 mm for three disks surrounding young brown dwarfs and very low mass stars in the Taurus star forming region. Dust thermal emission is detected and spatially resolved for all the three disks, while CO(J = 3-2) emission is seen in two disks. We analyze the continuum visibilities and constrain the disks' physical structure in dust. The results of our analysis show that the disks are relatively large; the smallest one has an outer radius of about 70 AU. The inferred disk radii, radial profiles of the dust surface density, and disk to central object mass ratios lie within the ranges found for disks around more massive young stars. We derive from our observations the wavelength dependence of the millimeter dust opacity. In all the three disks, data are consistent with the presence of grains with at least millimeter sizes, as also found for disks around young stars, and confirm that the early stages of the solid growth toward planetesimals occur also around very low-mass objects. We discuss the implications of our findings on models of solids evolution in protoplanetary disks, the main mechanisms proposed for the formation of brown dwarfs and very low-mass stars, as well as the potential of finding rocky and giant planets around very low-mass objects.

  3. The influence of neap-spring tidal variation and wave energy on sediment flux in salt marsh tidal creeks

    Science.gov (United States)

    Lacy, Jessica; Ferner, Matthew C.; Callaway, John C.

    2018-01-01

    Sediment flux in marsh tidal creeks is commonly used to gage sediment supply to marshes. We conducted a field investigation of temporal variability in sediment flux in tidal creeks in the accreting tidal marsh at China Camp State Park adjacent to northern San Francisco Bay. Suspended-sediment concentration (SSC), velocity, and depth were measured near the mouths of two tidal creeks during three six-to-ten-week deployments: two in winter and one in summer. Currents, wave properties and SSC were measured in the adjacent shallows. All deployments spanned the largest spring tides of the season. Results show that tidally-averaged suspended-sediment flux (SSF) in the tidal creeks decreased with increasing tidal energy, and SSF was negative (bayward) for tidal cycles with maximum water surface elevation above the marsh plain. Export during the largest spring tides dominated the cumulative SSF measured during the deployments. During ebb tides following the highest tides, velocities exceeded 1 m/s in the narrow tidal creeks, resulting in negative tidally-averaged water flux, and mobilizing sediment from the creek banks or bed. Storm surge also produced negative SSF. Tidally-averaged SSF was positive in wavey conditions with moderate tides. Spring-tide sediment export was about 50% less at a station 130 m further up the tidal creek than at the creek mouth. The negative tidally-averaged water flux near the creek mouth during spring tides indicates that in the lower marsh, some of the water flooding directly across the bay--marsh interface drains through the tidal creeks, and suggests that this interface may be a pathway for sediment supply to the lower marsh as well.

  4. Integrating tidal and nontidal ecological assessments

    Science.gov (United States)

    Mark Southerland; Roberto Llanso

    2016-01-01

    The Maryland Department of Natural Resources (DNR) has a long history of conducting rigorous assessments of ecological conditions in both tidal and nontidal waters. The Long-Term Benthic (LTB) Monitoring Program and the Maryland Biological Stream Survey (MBSS) both use reference-based indicators of benthic invertebrate communities to provide areawide estimates of ...

  5. Tidal heating in multilayered terrestrial exoplanets

    Energy Technology Data Exchange (ETDEWEB)

    Henning, Wade G.; Hurford, Terry, E-mail: wade.g.henning@nasa.gov [NASA Goddard Space Flight Center, 8800 Greenbelt Road, Greenbelt, MD 20771 (United States)

    2014-07-01

    The internal pattern and overall magnitude of tidal heating for spin-synchronous terrestrial exoplanets from 1 to 2.5 R{sub E} is investigated using a propagator matrix method for a variety of layer structures. Particular attention is paid to ice-silicate hybrid super-Earths, where a significant ice mantle is modeled to rest atop an iron-silicate core, and may or may not contain a liquid water ocean. We find multilayer modeling often increases tidal dissipation relative to a homogeneous model, across multiple orbital periods, due to the ability to include smaller volume low viscosity regions, and the added flexure allowed by liquid layers. Gradations in parameters with depth are explored, such as allowed by the Preliminary Earth Reference Model. For ice-silicate hybrid worlds, dramatically greater dissipation is possible beyond the case of a silicate mantle only, allowing non-negligible tidal activity to extend to greater orbital periods than previously predicted. Surface patterns of tidal heating are found to potentially be useful for distinguishing internal structure. The influence of ice mantle depth and water ocean size and position are shown for a range of forcing frequencies. Rates of orbital circularization are found to be 10-100 times faster than standard predictions for Earth-analog planets when interiors are moderately warmer than the modern Earth, as well as for a diverse range of ice-silicate hybrid super-Earths. Circularization rates are shown to be significantly longer for planets with layers equivalent to an ocean-free modern Earth, as well as for planets with high fractions of either ice or silicate melting.

  6. Tidal Heating in Multilayered Terrestrial Exoplanets

    Science.gov (United States)

    Henning, Wade G.; Hurford, Terry

    2014-01-01

    The internal pattern and overall magnitude of tidal heating for spin-synchronous terrestrial exoplanets from 1 to 2.5 R(sub E) is investigated using a propagator matrix method for a variety of layer structures. Particular attention is paid to ice-silicate hybrid super-Earths, where a significant ice mantle is modeled to rest atop an iron-silicate core, and may or may not contain a liquid water ocean. We find multilayer modeling often increases tidal dissipation relative to a homogeneous model, across multiple orbital periods, due to the ability to include smaller volume low viscosity regions, and the added flexure allowed by liquid layers. Gradations in parameters with depth are explored, such as allowed by the Preliminary Earth Reference Model. For ice-silicate hybrid worlds, dramatically greater dissipation is possible beyond the case of a silicate mantle only, allowing non-negligible tidal activity to extend to greater orbital periods than previously predicted. Surface patterns of tidal heating are found to potentially be useful for distinguishing internal structure. The influence of ice mantle depth and water ocean size and position are shown for a range of forcing frequencies. Rates of orbital circularization are found to be 10-100 times faster than standard predictions for Earth-analog planets when interiors are moderately warmer than the modern Earth, as well as for a diverse range of ice-silicate hybrid super-Earths. Circularization rates are shown to be significantly longer for planets with layers equivalent to an ocean-free modern Earth, as well as for planets with high fractions of either ice or silicate melting.

  7. The commercial prospects for tidal stream power

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-07-01

    The prospects for obtaining energy from tidal currents were examined in 1993 when it was concluded that, although the UK resource is large, the unit cost of energy would be relatively high. Interest has continued, however, and in December 2000 the Energy Technology Support Unit (ETSU), on behalf of the Department of Trade and Industry (DTI), commissioned Binnie Black and Veatch (BBV) to re-examine these prospects from a commercial point of view. (author)

  8. Effect of tidal fields on star clusters

    Science.gov (United States)

    Chernoff, David; Weinberg, Martin

    1991-01-01

    We follow the dynamical evolution of a star cluster in a galactic tidal field using a restricted N-body code. We find large asymmetric distortions in the outer profile of the cluster in the first 10 or so crossing times as material is lost. Prograde stars escape preferentially and establish a potentially observable retrograde rotation in the halo. We present the rate of particle loss and compare with the prescription proposed by Lee and Ostriker (1987).

  9. Tidal power from the River Mersey

    International Nuclear Information System (INIS)

    1991-01-01

    The studies described in this report relate to work carried out since those reported upon in the stage I Mersey Barrage Report on the possible construction of a tidal power barrage on the Mersey Estuary. The objectives of the work were to review basic engineering, re-assess cost and energy output, improve engineering configuration, quantify social, industrial and regional effects, determine preferred alignment, review the main environmental impacts, assess economic viability and financing and identify further study requirements. (UK)

  10. Tidal heating in multilayered terrestrial exoplanets

    International Nuclear Information System (INIS)

    Henning, Wade G.; Hurford, Terry

    2014-01-01

    The internal pattern and overall magnitude of tidal heating for spin-synchronous terrestrial exoplanets from 1 to 2.5 R E is investigated using a propagator matrix method for a variety of layer structures. Particular attention is paid to ice-silicate hybrid super-Earths, where a significant ice mantle is modeled to rest atop an iron-silicate core, and may or may not contain a liquid water ocean. We find multilayer modeling often increases tidal dissipation relative to a homogeneous model, across multiple orbital periods, due to the ability to include smaller volume low viscosity regions, and the added flexure allowed by liquid layers. Gradations in parameters with depth are explored, such as allowed by the Preliminary Earth Reference Model. For ice-silicate hybrid worlds, dramatically greater dissipation is possible beyond the case of a silicate mantle only, allowing non-negligible tidal activity to extend to greater orbital periods than previously predicted. Surface patterns of tidal heating are found to potentially be useful for distinguishing internal structure. The influence of ice mantle depth and water ocean size and position are shown for a range of forcing frequencies. Rates of orbital circularization are found to be 10-100 times faster than standard predictions for Earth-analog planets when interiors are moderately warmer than the modern Earth, as well as for a diverse range of ice-silicate hybrid super-Earths. Circularization rates are shown to be significantly longer for planets with layers equivalent to an ocean-free modern Earth, as well as for planets with high fractions of either ice or silicate melting.

  11. Tidal controls on river delta morphology

    Science.gov (United States)

    Hoitink, A. J. F.; Wang, Z. B.; Vermeulen, B.; Huismans, Y.; Kästner, K.

    2017-09-01

    River delta degradation has been caused by extraction of natural resources, sediment retention by reservoirs, and sea-level rise. Despite global concerns about these issues, human activity in the world’s largest deltas intensifies. Harbour development, construction of flood defences, sand mining and land reclamation emerge as key contemporary factors that exert an impact on delta morphology. Tides interacting with river discharge can play a crucial role in the morphodynamic development of deltas under pressure. Emerging insights into tidal controls on river delta morphology suggest that--despite the active morphodynamics in tidal channels and mouth bar regions--tidal motion acts to stabilize delta morphology at the landscape scale under the condition that sediment import during low flows largely balances sediment export during high flows. Distributary channels subject to tides show lower migration rates and are less easily flooded by the river because of opposing non-linear interactions between river discharge and the tide. These interactions lead to flow changes within channels, and a more uniform distribution of discharge across channels. Sediment depletion and rigorous human interventions in deltas, including storm surge defence works, disrupt the dynamic morphological equilibrium and can lead to erosion and severe scour at the channel bed, even decades after an intervention.

  12. Tidally Driven Failure Along Europa's Rhadamanthys Linea

    Science.gov (United States)

    Cameron, M.; Konter, B.; Pappalardo, R. T.

    2013-12-01

    The surface of Europa is crosscut by a dense network of fractures and there are many candidate faults for studying past tectonic activity. To better understand the role of tidal stress sources and implications for faulting on Europa, we investigate the relationship between shear and normal stresses at Rhadamanthys Linea, a northwest oriented fracture in the northern hemisphere. Previous work on Agenor Linea, a right-lateral strike-slip fracture in the southern hemisphere, suggests that both tidal diurnal and non-synchronous rotation (NSR) stresses play a critical role in the mechanics of Coulomb shear failure on Europa. At Agenor Linea, shear failure from diurnal tidal stress mechanisms is difficult to achieve because the relatively large over¬burden stress (ie., 1.2 MPa at 1 km depth) dominates the stress field; however, MPa order stresses from NSR permit right-lateral shear failure along the west side of the fault at shallow depths (Astypalea Linea and Conamara Chaos will also be investigated, offering a unique comparison of geologic activity of fractures residing in geographically diverse locations of Europa.

  13. Tidal controls on earthquake size-frequency statistics

    Science.gov (United States)

    Ide, S.; Yabe, S.; Tanaka, Y.

    2016-12-01

    The possibility that tidal stresses can trigger earthquakes is a long-standing issue in seismology. Except in some special cases, a causal relationship between seismicity and the phase of tidal stress has been rejected on the basis of studies using many small events. However, recently discovered deep tectonic tremors are highly sensitive to tidal stress levels, with the relationship being governed by a nonlinear law according to which the tremor rate increases exponentially with increasing stress; thus, slow deformation (and the probability of earthquakes) may be enhanced during periods of large tidal stress. Here, we show the influence of tidal stress on seismicity by calculating histories of tidal shear stress during the 2-week period before earthquakes. Very large earthquakes tend to occur near the time of maximum tidal stress, but this tendency is not obvious for small earthquakes. Rather, we found that tidal stress controls the earthquake size-frequency statistics; i.e., the fraction of large events increases (i.e. the b-value of the Gutenberg-Richter relation decreases) as the tidal shear stress increases. This correlation is apparent in data from the global catalog and in relatively homogeneous regional catalogues of earthquakes in Japan. The relationship is also reasonable, considering the well-known relationship between stress and the b-value. Our findings indicate that the probability of a tiny rock failure expanding to a gigantic rupture increases with increasing tidal stress levels. This finding has clear implications for probabilistic earthquake forecasting.

  14. The effects of tidal range on saltmarsh morphology

    Science.gov (United States)

    Goodwin, Guillaume; Mudd, Simon

    2017-04-01

    Saltmarshes are highly productive coastal ecosystems that act simultaneously as flood barriers, carbon storage, pollutant filters and nurseries. As halophytic plants trap suspended sediment and decay in the settled strata, innervated platforms emerge from the neighbouring tidal flats, forming sub-vertical scarps on their eroding borders and sub-horizontal pioneer zones in areas of seasonal expansion. These evolutions are subject to two contrasting influences: stochastically generated waves erode scarps and scour tidal flats, whereas tidally-generated currents transport sediment to and from the marsh through the channel network. Hence, the relative power of waves and tidal currents strongly influences saltmarsh evolution, and regional variations in tidal range yield marshes of differing morphologies. We analyse several sheltered saltmarshes to determine how their morphology reflects variations in tidal forcing. Using tidal, topographic and spectral data, we implement an algorithm based on the open-source software LSDTopoTools to automatically identify features such as marsh platforms, tidal flats, erosion scarps, pioneer zones and tidal channels on local Digital Elevation Models. Normalised geometric properties are then computed and compared throughout the spectrum of tidal range, highlighting a notable effect on channel networks, platform geometry and wave exposure. We observe that micro-tidal marshes typically display jagged outlines and multiple islands along with wide, shallow channels. As tidal range increases, we note the progressive disappearance of marsh islands and linearization of scarps, both indicative of higher hydrodynamic stress, along with a structuration of channel networks and the increase of levee volume, suggesting higher sediment input on the platform. Future research will lead to observing and modelling the evolution of saltmarshes under various tidal forcing in order to assess their resilience to environmental change.

  15. Thermochemical modelling of brown dwarf discs

    NARCIS (Netherlands)

    Greenwood, A. J.; Kamp, I.; Waters, L. B. F. M.; Woitke, P.; Thi, W.-F.; Rab, Ch.; Aresu, G.; Spaans, M.

    The physical properties of brown dwarf discs, in terms of their shapes and sizes, are still largely unexplored by observations. ALMA has by far the best capabilities to observe these discs in sub-mm CO lines and dust continuum, while also spatially resolving some discs. To what extent brown dwarf

  16. Isolation of glycoproteins from brown algae

    DEFF Research Database (Denmark)

    2015-01-01

    The present invention relates to a novel process for the isolation of unique anti-oxidative glycoproteins from the pH precipitated fractions of enzymatic extracts of brown algae. Two brown seaweeds viz, Fucus serratus and Fucus vesiculosus were hydrolysed by using 3 enzymes viz, Alcalase, Viscozyme...

  17. Relying on fin erosion to identify hatchery-reared brown trout in a Tennessee river

    Science.gov (United States)

    Meerbeek, Jonathan R.; Bettoli, Phillip William

    2012-01-01

    Hatchery-induced fin erosion can be used to identify recently stocked catchable-size brown trout Salmo trutta during annual surveys to qualitatively estimate contributions to a fishery. However, little is known about the longevity of this mark and its effectiveness as a short-term (≤ 1 year) mass-marking technique. We evaluated hatchery-induced pectoral fin erosion as a mass-marking technique for short-term stocking evaluations by stocking microtagged brown trout in a tailwater and repeatedly sampling those fish to observe and measure their pectoral fins. At Dale Hollow National Fish Hatchery, 99.1% (228 of 230) of microtagged brown trout in outdoor concrete raceways had eroded pectoral fins 1 d prior to stocking. Between 34 and 68 microtagged and 26-35 wild brown trout were collected during eight subsequent electrofishing samples. In a blind test based on visual examination of pectoral fins at up to 322 d poststocking, one observer correctly identified 91.7% to 100.0% (mean of 96.9%) of microtagged brown trout prior to checking for microtags. In the laboratory, pectoral fin length and width measurements were recorded to statistically compare the fin measurements of wild and microtagged hatchery brown trout. With only one exception, all pectoral fin measurements on each date averaged significantly larger for wild trout than for microtagged brown trout. Based on the number of pectoral fin measurements falling below 95% prediction intervals, 93.7% (148 of 158) of microtagged trout were correctly identified as hatchery fish based on regression models up to 160 d poststocking. Only 72.2% (70 of 97) of microtagged trout were identified correctly after 160 d based on pectoral fin measurements and the regression models. We concluded that visual examination of pectoral fin erosion was a very effective way to identify stocked brown trout for up to 322 d poststocking.

  18. Satellite Tidal Magnetic Signals Constrain Oceanic Lithosphere-Asthenosphere Boundary Earth Tomography with Tidal Magnetic Signals

    Science.gov (United States)

    Grayver, Alexander V.; Schnepf, Neesha R.; Kuvshinov, Alexey V.; Sabaka, Terence J.; Chandrasekharan, Manoj; Olsen, Niles

    2016-01-01

    The tidal flow of electrically conductive oceans through the geomagnetic field results in the generation of secondary magnetic signals, which provide information on the subsurface structure. Data from the new generation of satellites were shown to contain magnetic signals due to tidal flow; however, there are no reports that these signals have been used to infer subsurface structure. Here we use satellite-detected tidal magnetic fields to image the global electrical structure of the oceanic lithosphere and upper mantle down to a depth of about 250 km. The model derived from more than 12 years of satellite data reveals an Approximately 72 km thick upper resistive layer followed by a sharp increase in electrical conductivity likely associated with the lithosphere-asthenosphere boundary, which separates colder rigid oceanic plates from the ductile and hotter asthenosphere.

  19. Lower tidal volume strategy (?3?ml/kg) combined with extracorporeal CO2 removal versus ?conventional? protective ventilation (6?ml/kg) in severe ARDS

    OpenAIRE

    Bein, Thomas; Weber-Carstens, Steffen; Goldmann, Anton; M?ller, Thomas; Staudinger, Thomas; Brederlau, J?rg; Muellenbach, Ralf; Dembinski, Rolf; Graf, Bernhard M.; Wewalka, Marlene; Philipp, Alois; Wernecke, Klaus-Dieter; Lubnow, Matthias; Slutsky, Arthur S.

    2013-01-01

    Background Acute respiratory distress syndrome is characterized by damage to the lung caused by various insults, including ventilation itself, and tidal hyperinflation can lead to ventilator induced lung injury (VILI). We investigated the effects of a low tidal volume (V T) strategy (V T???3?ml/kg/predicted body weight [PBW]) using pumpless extracorporeal lung assist in established ARDS. Methods Seventy-nine patients were enrolled after a ?stabilization period? (24?h with optimized therapy an...

  20. Habitable planets around white and brown dwarfs: the perils of a cooling primary.

    Science.gov (United States)

    Barnes, Rory; Heller, René

    2013-03-01

    White and brown dwarfs are astrophysical objects that are bright enough to support an insolation habitable zone (IHZ). Unlike hydrogen-burning stars, they cool and become less luminous with time; hence their IHZ moves in with time. The inner edge of the IHZ is defined as the orbital radius at which a planet may enter a moist or runaway greenhouse, phenomena that can remove a planet's surface water forever. Thus, as the IHZ moves in, planets that enter it may no longer have any water and are still uninhabitable. Additionally, the close proximity of the IHZ to the primary leads to concern that tidal heating may also be strong enough to trigger a runaway greenhouse, even for orbital eccentricities as small as 10(-6). Water loss occurs due to photolyzation by UV photons in the planetary stratosphere, followed by hydrogen escape. Young white dwarfs emit a large amount of these photons, as their surface temperatures are over 10(4) K. The situation is less clear for brown dwarfs, as observational data do not constrain their early activity and UV emission very well. Nonetheless, both types of planets are at risk of never achieving habitable conditions, but planets orbiting white dwarfs may be less likely to sustain life than those orbiting brown dwarfs. We consider the future habitability of the planet candidates KOI 55.01 and 55.02 in these terms and find they are unlikely to become habitable.

  1. Browning boreal forests of western North America

    Science.gov (United States)

    Verbyla, David

    2011-12-01

    The GIMMS NDVI dataset has been widely used to document a 'browning trend' in North American boreal forests (Goetz et al 2005, Bunn et al 2007, Beck and Goetz 2011). However, there has been speculation (Alcaraz-Segura et al 2010) that this trend may be an artifact due to processing algorithms rather than an actual decline in vegetation activity. This conclusion was based primarily on the fact that GIMMS NDVI did not capture NDVI recovery within most burned areas in boreal Canada, while another dataset consistently showed post-fire increasing NDVI. I believe that the results of Alcaraz-Segura et al (2010) were due simply to different pixel sizes of the two datasets (64 km2 versus 1 km2 pixels). Similar results have been obtained from tundra areas greening in Alaska, with the results simply due to these pixel size differences (Stow et al 2007). Furthermore, recent studies have documented boreal browning trends based on NDVI from other sensors. Beck and Goetz (2011) have shown the boreal browning trend derived from a different sensor (MODIS) to be very similar to the boreal browning trend derived from the GIMMS NDVI dataset for the circumpolar boreal region. Parent and Verbyla (2010) found similar declining NDVI patterns based on NDVI from Landsat sensors and GIMMS NDVI in boreal Alaska. Zhang et al (2008) found a similar 'browning trend' in boreal North America based on a production efficiency model using an integrated AVHRR and MODIS dataset. The declining NDVI trend in areas of boreal North America is consistent with tree-ring studies (D'Arrigo et al 2004, McGuire et al 2010, Beck et al 2011). The decline in tree growth may be due to temperature-induced drought stress (Barber et al 2000) caused by higher evaporative demands in a warming climate (Lloyd and Fastie 2002). In a circumpolar boreal study, Lloyd and Bunn (2007) found that a negative relationship between temperature and tree-ring growth occurred more frequently in warmer parts of species' ranges

  2. From Globular Clusters to Tidal Dwarfs: Structure Formation in the Tidal Tails of Merging Galaxies

    Science.gov (United States)

    Knierman, Karen A.; Gallagher, Sarah C.; Charlton, Jane C.; Hunsberger, Sally D.; Whitmore, Bradley; Kundu, Arunav; Hibbard, J. E.; Zaritsky, Dennis

    2003-09-01

    Using V and I images obtained with the Wide Field Planetary Camera 2 (WFPC2) of the Hubble Space Telescope, we investigate compact stellar structures within tidal tails. Six regions of tidal debris in the four classic ``Toomre sequence'' mergers: NGC 4038/39 (``Antennae''), NGC 3256, NGC 3921, and NGC 7252 (``Atoms for Peace'') have been studied in order to explore how the star formation depends on the local and global physical conditions. These mergers sample a range of stages in the evolutionary sequence and tails with and without embedded tidal dwarf galaxies. The six tails are found to contain a variety of stellar structures, with sizes ranging from those of globular clusters up to those of dwarf galaxies. From V and I WFPC2 images, we measure the luminosities and colors of the star clusters. NGC 3256 is found to have a large population of blue clusters (0.2<~V-I<~0.9), particularly in its western tail, similar to those found in the inner region of the merger. In contrast, NGC 4038/39 has no clusters in the observed region of the tail, only less luminous point sources likely to be individual stars. NGC 3921 and NGC 7252 have small populations of clusters along their tails. A significant cluster population is clearly associated with the prominent tidal dwarf candidates in the eastern and western tails of NGC 7252. The cluster-rich western tail of NGC 3256 is not distinguished from the others by its dynamical age or by its total H I mass. However, the mergers that have few clusters in the tail all have tidal dwarf galaxies, while NGC 3256 does not have prominent tidal dwarfs. We speculate that star formation in tidal tails may manifest itself either in small structures like clusters along the tail or in large structures such as dwarf galaxies, but not in both. Also, NGC 3256 has the highest star formation rate of the four mergers studied, which may contribute to the high number of star clusters in its tidal tails. Based in part on observations obtained with the

  3. Inspiratory time and tidal volume during intermittent positive pressure ventilation.

    OpenAIRE

    Field, D; Milner, A D; Hopkin, I E

    1985-01-01

    We measured the tidal volume achieved during intermittent positive pressure ventilation using various inspiratory times with a minimum of 0.2 seconds. Results indicate that tidal volume shows no reduction with inspiratory times down to 0.4 seconds. An inspiratory time of 0.3 seconds, however, is likely to reduce tidal volume by 8%, and at 0.2 seconds a 22% fall may be anticipated.

  4. Tidal effects on groundwater contamination at Pekan, Pahang

    International Nuclear Information System (INIS)

    Nor Dalila Desa; Dominic, J.A.; Mohd Muzamil Mohd Hashim; Kamarudin Samuding; Mohd Faizun Khalid; Mod Omar Hassan; Kamaruzaman Mohamad

    2014-01-01

    The meeting of coastal ground water and the sea is a unique and dynamic hydro geologic boundary phenomenon that has fascinated groundwater engineers and scientists for the past century. The variation of seawater level resulting from tidal fluctuations is usually neglected in regional groundwater flow studies. In this study the effects of seawater tidal on groundwater are investigated using geophysical together with conventional method. Comparative result between these two methods shown how tidal fluctuations effects groundwater in study area. (author)

  5. Dietary Fat Overload Reprograms Brown Fat Mitochondria

    Directory of Open Access Journals (Sweden)

    DANIELE eLETTIERI BARBATO

    2015-09-01

    Full Text Available Chronic nutrient overload accelerates the onset of several aging-related diseases reducing life expectancy. Although the mechanisms by which overnutrition affects metabolic processes in many tissues are known, its role on BAT physiology is still unclear. Herein, we investigated the mitochondrial responses in BAT of female mice exposed to high fat diet (HFD at different steps of life. Although adult mice showed an unchanged mitochondrial amount, both respiration and OxPHOS subunits were strongly affected. Differently, offspring pups exposed to HFD during pregnancy and lactation displayed reduced mitochondrial mass but high oxidative efficiency that, however, resulted in increased bioenergetics state of BAT rather than augmented uncoupling respiration. Interestingly, the metabolic responses triggered by HFD were accompanied by changes in mitochondrial dynamics characterized by decreased content of the fragmentation marker Drp1 both in mothers and offspring pups. HFD-induced inactivation of the FoxO1 transcription factor seemed to be the up-stream modulator of Drp1 levels in brown fat cells. Furthermore, HFD offspring pups weaned with normal diet only partially reverted the mitochondrial dysfunctions caused by HFD. Finally these mice failed in activating the thermogenic program upon cold exposure. Collectively our findings suggest that maternal dietary fat overload irreversibly commits BAT unresponsiveness to physiological stimuli such as cool temperature and this dysfunction in the early stage of life might negatively modulates health and lifespan.

  6. The Formation of Super-Earths by Tidally Forced Turbulence

    Science.gov (United States)

    Yu, Cong

    2017-12-01

    The Kepler observations indicate that many exoplanets are super-Earths, which brings about a puzzle for the core-accretion scenario. Since observed super-Earths are in the range of critical mass, they accrete gas efficiently and become gas giants. Theoretically, super-Earths are predicted to be rare in the core-accretion framework. To resolve this contradiction, we propose that the tidally forced turbulent diffusion may affect the heat transport inside the planet. Thermal feedback induced by turbulent diffusion is investigated. We find that the tidally forced turbulence generates pseudo-adiabatic regions within radiative zones, which pushes the radiative-convective boundaries inward. This decreases the cooling luminosity and enhances the Kelvin-Helmholtz (KH) timescale. For a given lifetime of protoplanetary disks (PPDs), there exists a critical threshold for the turbulent diffusivity, ν critical. If ν turb > ν critical, the KH timescale is longer than the disk lifetime and the planet becomes a super-Earth, rather than a gas giant. We find that even a small value of turbulent diffusion has influential effects on the evolution of super-Earths. The ν critical increases with the core mass. We further ascertain that, within the minimum-mass extrasolar nebula, ν critical increases with the semimajor axis. This may explain the feature that super-Earths are common in inner PPD regions, while gas giants are common in outer PPD regions. The predicted envelope mass fraction is not fully consistent with observations. We discuss physical processes, such as late core assembly and mass-loss mechanisms, that may be operating during super-Earth formation.

  7. Tidally-driven Surface Flow in a Georgia Estuarine Saltmarsh

    Science.gov (United States)

    Young, D.; Bruder, B. L.; Haas, K. A.; Webster, D. R.

    2016-02-01

    Estuarine saltmarshes are diverse, valuable, and productive ecosystems. Vegetation dampens wave and current energy, thereby allowing the estuaries to serve as a nursery habitat for shellfish and fish species. Tidally-driven flow transports nutrients into and out of the estuary, nourishing inshore and offshore vegetation and animals. The effects of vegetation on the marsh hydrodynamics and on the estuary creek and channel flow are, unfortunately, poorly understood, and the knowledge that does exist primarily originates from modeling studies. Field studies addressing marsh surface flows are limited due to the difficulty of accurately measuring the water surface elevation and acquiring concurrent velocity measurements in the dense marsh vegetation. This study partially bridges the gap between the model observations of marsh flow driven by water surface elevation gradients and flume studies of flow through vegetation. Three current meters and three pressure transducers were deployed for three days along a transect perpendicular to the main channel (Little Ogeechee River) in a saltmarsh adjacent to Rose Dhu Island (Savannah, Georgia, USA). The pressure transducer locations were surveyed daily with static GPS yielding highly accurate water surface elevation data. During flood and ebb tide, water surface elevation differences between the marsh and Little Ogeechee River were observed up to 15 cm and pressure gradients were observed up to 0.0017 m of water surface elevation drop per m of linear distance. The resulting channel-to-saltmarsh pressure gradients substantially affected tidal currents at all current meters. At one current meter, the velocity was nearly perpendicular to the Little Ogeechee River bank. The velocity at this location was effectively modeled as a balance between the pressure gradient and marsh vegetation-induced drag force using the Darcy-Weisbach/Lindner's equations developed for flow-through-vegetation analysis in open channel flow.

  8. Tidal analysis of surface currents in the Porsanger fjord in northern Norway

    Science.gov (United States)

    Stramska, Malgorzata; Jankowski, Andrzej; Cieszyńska, Agata

    2016-04-01

    In this presentation we describe surface currents in the Porsanger fjord (Porsangerfjorden) located in the European Arctic in the vicinity of the Barents Sea. Our analysis is based on data collected in the summer of 2014 using High Frequency radar system. Our interest in this fjord comes from the fact that this is a region of high climatic sensitivity. One of our long-term goals is to develop an improved understanding of the undergoing changes and interactions between this fjord and the large-scale atmospheric and oceanic conditions. In order to derive a better understanding of the ongoing changes one must first improve the knowledge about the physical processes that create the environment of the fjord. The present study is the first step in this direction. Our main objective in this presentation is to evaluate the importance of tidal forcing. Tides in the Porsanger fjord are substantial, with tidal range on the order of about 3 meters. Tidal analysis attributes to tides about 99% of variance in sea level time series recorded in Honningsvåg. The most important tidal component based on sea level data is the M2 component (amplitude of ~90 cm). The S2 and N2 components (amplitude of ~ 20 cm) also play a significant role in the semidiurnal sea level oscillations. The most important diurnal component is K1 with amplitude of about 8 cm. Tidal analysis lead us to the conclusion that the most important tidal component in observed surface currents is also the M2 component. The second most important component is the S2 component. Our results indicate that in contrast to sea level, only about 10 - 20% of variance in surface currents can be attributed to tidal currents. This means that about 80-90% of variance can be credited to wind-induced and geostrophic currents. This work was funded by the Norway Grants (NCBR contract No. 201985, project NORDFLUX). Partial support for MS comes from the Institute of Oceanology (IO PAN).

  9. Tidal sails : an alternative to turbines for harvesting tidal current energy

    Energy Technology Data Exchange (ETDEWEB)

    Hanssen, J.E. [Tidal Sails, Haugesund (Norway)

    2008-07-01

    Tidal sail technology harnesses the energy of tidal streams in order to produce electricity. Tidal currents move the sails that are attached to wires that rotate generator wheels to produce electricity. The technology has a low impact on the surrounding environment and is simple to install. This presentation discussed the methods used to determine the influence of relative sail velocity and measure estimated energy output levels. The sails were recently tested at an on-grid tidal stream pilot in the Norwegian Arctic. A 300 kW turbine installed at the site demonstrated that the site was suitable for a full-scale development of 20 tripod-mounted 600 kW turbines placed at 50 m depth. It was estimated that the 10 strings of 1000 m length provided between 200 and 250 GWh per year. The sails have also been used at a high speed site in Washington state in the United States. The 25 m pilot plant was installed to verify site suitability and examine sail behaviour in real, high-flow currents. It is expected that the technology will be fully commercialized by 2011. Other pilot tests are being conducted to examine flow behaviour; mooring and flotation functionality; and launch and lift capabilities. Engineering work is ongoing to examine plant designs, variable sail spacing, and collaborations with key component suppliers. tabs., figs.

  10. Waddenfonds Tidal Texel Demonstration project. BlueTEC Texel Tidal Project: Environmental measurement and performance analysis

    NARCIS (Netherlands)

    Ponsoni, L.; Nauw, J.J.; Smit, M.; Ober, S.; Nichols, C.; Kenkhuis, J.; Schmidt, C.; Buatois, A.; de Haas, P.

    2016-01-01

    In the context of the BlueTEC project, this report starts by introducing theBlueTEC tidal energy platform and reviewing the patterns of circulation of theMarsdiep inlet. The energy resource assessment and the site selection for theplatform's deployment are reported. This document analyses di?erent

  11. Atmospheric dynamics of tidally synchronized extrasolar planets.

    Science.gov (United States)

    Cho, James Y-K

    2008-12-13

    Tidally synchronized planets present a new opportunity for enriching our understanding of atmospheric dynamics on planets. Subject to an unusual forcing arrangement (steady irradiation on the same side of the planet throughout its orbit), the dynamics on these planets may be unlike that on any of the Solar System planets. Characterizing the flow pattern and temperature distribution on the extrasolar planets is necessary for reliable interpretation of data currently being collected, as well as for guiding future observations. In this paper, several fundamental concepts from atmospheric dynamics, likely to be central for characterization, are discussed. Theoretical issues that need to be addressed in the near future are also highlighted.

  12. Physics and observations of tidal disruption events

    Science.gov (United States)

    Mangalam, Arun; Mageshwaran, Tamilan

    2018-04-01

    We describe a model of tidal disruption events (TDEs) with input physical parameters that include the black hole (BH) mass M•, the specific orbital energy E, the angular momentum J, the star mass M⊙ and radius R⊙. We calculate the rise time of the TDEs, the peak bolometric luminosity in terms of these physical parameters and a typical light curve of TDEs for various All Sky Survey (ASS) and Deep Sky Survey (DSS) missions. We then derive the expected detection rates and discuss the follow up of TDEs through observations in various spectral bands from X-rays to radio wavelengths.

  13. Comprehensive Characterization a Tidal Energy Site (Invited)

    Science.gov (United States)

    Polagye, B. L.; Thomson, J. M.; Bassett, C. S.; Epler, J.; Northwest National Marine Renewable Energy Center

    2010-12-01

    Northern Admiralty Inlet, Puget Sound, Washington is the proposed location of a pilot tidal energy project. Site-specific characterization of the physical and biological environment is required for device engineering and environmental analysis. However, the deep water and strong currents which make the site attractive for tidal energy development also pose unique challenges to collecting comprehensive information. This talk focuses on efforts to optimally site hydrokinetic turbines and estimate their acoustic impact, based on 18 months of field data collected to date. Additional characterization efforts being undertaken by the University of Washington branch of the Northwest National Marine Renewable Energy Center and its partners include marine mammal presence and behavior, water quality, seabed geology, and biofouling potential. Because kinetic power density varies with the cube of horizontal current velocity, an accurate map of spatial current variations is required to optimally site hydrokinetic turbines. Acoustic Doppler profilers deployed on the seabed show operationally meaningful variations in flow characteristics (e.g., power density, directionality, vertical shear) and tidal harmonic constituents over length scales of less than 100m. This is, in part, attributed to the proximity of this site to a headland. Because of these variations, interpolation between stationary measurement locations introduces potentially high uncertainty. The use of shipboard acoustic Doppler profilers is shown to be an effective tool for mapping peak currents and, combined with information from seabed profilers, may be able to resolve power density variations in the project area. Because noise levels from operating turbines are expected to exceed regulatory thresholds for incidental harassment of marine mammals known to be present in the project area, an estimate of the acoustic footprint is required to permit the pilot project. This requires site-specific descriptions of pre

  14. Tidal Wetlands and Coastal Ocean Carbon Dynamics

    Science.gov (United States)

    Hopkinson, C.; Wang, S. R.; Forbrich, I.; Giblin, A. E.; Cai, W. J.

    2017-12-01

    Recent overviews of coastal ocean C dynamics have tidal wetlands in a prominent position: a local sink for atmospheric CO2, a local store of OC, and a source of DIC and OC for the adjacent estuary and nearshore ocean. Over the past decade there have been great strides made in quantifying and understanding these flows and linkages. GPP and R of the wetlands are not nearly as imbalanced as thought 30 yrs ago. Heterotrophy of adjacent estuarine waters is not solely due to the respiration of OC exported from the marsh, rather we see the marsh directly respiring into the water during tidal inundation and accumulated marsh DIC draining into tidal creeks. Organic carbon burial on the marsh is still a relatively minor flux, but it is large relative to marsh NEE. Using literature and unpublished data on marsh DIC export, we used examples from Sapelo Island GA USA and Plum Island MA USA to constrain estimates of NEP and potential OC export. P. There remain large uncertainties in quantifying C dynamics of coupled wetland - estuary systems. Gas exchange from the water to atmosphere is one of the largest uncertainties. Work at Sapelo suggests that upwards of 40% of all daily exchange occurs from water flooding the marsh, which is but a few hours a day. This estimate is based on the intercept value for gas exchange vs wind velocity. Another major uncertainty comes from converting between O2 based estimates of metabolism to C. At Sapelo we find PQ and RQ values diverging greatly from Redfield. Finally, C dynamics of the coastal ocean, especially the role of tidal wetlands is likely to change substantially in the future. Studies at Plum Island show a reversal of the 4000 yr process of marsh progradation with marshes eroding away at their edges because of inadequate sediment supply and rising sea level. The fate of eroded OC is questionable. Landward transgression with SLR is the only likely counter to continued wetland loss - but that's a complex social issue requiring new

  15. Complex interaction between proliferative kidney disease, water temperature and concurrent nematode infection in brown trout.

    Science.gov (United States)

    Schmidt-Posthaus, Heike; Steiner, Pascale; Müller, Barbara; Casanova-Nakayama, Ayako

    2013-04-29

    Proliferative kidney disease (PKD) is a temperature-dependent disease caused by the myxozoan Tetracapsuloides bryosalmonae. It is an emerging threat to wild brown trout Salmo trutta fario populations in Switzerland. Here we examined (1) how PKD prevalence and pathology in young-of-the-year (YOY) brown trout relate to water temperature, (2) whether wild brown trout can completely recover from T. bryosalmonae-induced renal lesions and eliminate T. bryosalmonae over the winter months, and (3) whether this rate and/or extent of the recovery is influenced by concurrent infection. A longitudinal field study on a wild brown trout cohort was conducted over 16 mo. YOY and age 1+ fish were sampled from 7 different field sites with various temperature regimes, and monitored for infection with T. bryosalmonae and the nematode Raphidascaris acus. T. bryosamonae was detectable in brown trout YOY from all sampling sites, with similar renal pathology, independent of water temperature. During winter months, recovery was mainly influenced by the presence or absence of concurrent infection with R. acus larvae. While brown trout without R. acus regenerated completely, concurrently infected brown trout showed incomplete recovery, with chronic renal lesions and incomplete translocation of T. bryosalmonae from the renal interstitium into the tubular lumen. Water temperature seemed to influence complete excretion of T. bryosalmonae, with spores remaining in trout from summer-warm rivers, but absent in trout from summer-cool rivers. In the following summer months, we found PKD infections in 1+ brown trout from all investigated river sites. The pathological lesions indicated a re-infection rather than a proliferation of remaining T. bryosalmonae. However, disease prevalence in 1+ trout was lower than in YOY.

  16. Initial Assessment of β3-Adrenoceptor-Activated Brown Adipose Tissue in Streptozotocin-Induced Type 1 Diabetes Rodent Model Using [18F]Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography

    Directory of Open Access Journals (Sweden)

    Aparna Baranwal

    2015-12-01

    Full Text Available Metabolic activity of brown adipose tissue (BAT is activated by β3-adrenoceptor agonists and norepinephrine transporter (NET blockers and is measurable using [18F]fluorodeoxyglucose ([18F]FDG positron emission tomography/computed tomography (PET/CT in rats. Using the streptozotocin (STZ-treated rat model of type 1 diabetes mellitus (T1DM, we investigated BAT activity in this rat model under fasting and nonfasting conditions using [18F]FDG PET/CT. Drugs that enhance BAT activity may have a potential for therapeutic development in lowering blood sugar in insulin-resistant diabetes. Rats were rendered diabetic by administration of STZand confirmed by glucose measures. [18F]FDG was injected in the rats (fasted or nonfasted pretreated with either saline or β3-adrenoceptor agonist CL316,243 or the NET blocker atomoxetine for PET/CT scans. [18F]FDG metabolic activity was computed as standard uptake values (SUVs in interscapular brown adipose tissue (IBAT and compared across the different drug treatment conditions. Blood glucose levels > 500 mg/dL were established for the STZ-treated diabetic rats. Under fasting conditions, average uptake of [18F]FDG in the IBAT of STZ-treated diabetic rats was approximately 70% lower compared to that of normal rats. Both CL316,243 and atomoxetine activated IBAT in normal rats had an SUV > 5, whereas activation in STZ-treated rats was significantly lower. The agonist CL316,243 activated IBAT up to threefold compared to saline in the fasted STZ-treated rat. In the nonfasted rat, the IBAT activation was up by twofold by CL316243. Atomoxetine had a greater effect on lowering blood sugar levels compared to CL316,243 in the nonfasted rats. A significant reduction in metabolic activity was observed in the STZ-treated diabetic rodent model. Increased IBAT activity in the STZ-treated diabetic rat under nonfasted conditions using the β3-adrenoceptor agonist CL316,243 suggests a potential role of BAT in modulating blood sugar

  17. Sensitivity of growth characteristics of tidal sand ridges and long bed waves to formulations of bed shear stress, sand transport and tidal forcing : A numerical model study

    NARCIS (Netherlands)

    Yuan, Bing; de Swart, Huib E.; Panadès, Carles

    2016-01-01

    Tidal sand ridges and long bed waves are large-scale bedforms that are observed on continental shelves. They differ in their wavelength and in their orientation with respect to the principal direction of tidal currents. Previous studies indicate that tidal sand ridges appear in areas where tidal

  18. Conditions for tidal bore formation in convergent alluvial estuaries

    Science.gov (United States)

    Bonneton, Philippe; Filippini, Andrea Gilberto; Arpaia, Luca; Bonneton, Natalie; Ricchiuto, Mario

    2016-04-01

    Over the last decade there has been an increasing interest in tidal bore dynamics. However most studies have been focused on small-scale bore processes. The present paper describes the first quantitative study, at the estuary scale, of the conditions for tidal bore formation in convergent alluvial estuaries. When freshwater discharge and large-scale spatial variations of the estuary water depth can be neglected, tide propagation in such estuaries is controlled by three main dimensionless parameters: the nonlinearity parameter ε0 , the convergence ratio δ0 and the friction parameter ϕ0. In this paper we explore this dimensionless parameter space, in terms of tidal bore occurrence, from a database of 21 estuaries (8 tidal-bore estuaries and 13 non tidal-bore estuaries). The field data point out that tidal bores occur for convergence ratios close to the critical convergence δc. A new proposed definition of the friction parameter highlights a clear separation on the parameter plane (ϕ0,ε0) between tidal-bore estuaries and non tidal-bore estuaries. More specifically, we have established that tidal bores occur in convergent estuaries when the nonlinearity parameter is greater than a critical value, εc , which is an increasing function of the friction parameter ϕ0. This result has been confirmed by numerical simulations of the two-dimensional Saint Venant equations. The real-estuary observations and the numerical simulations also show that, contrary to what is generally assumed, tide amplification is not a necessary condition for tidal bore formation. The effect of freshwater discharge on tidal bore occurrence has been analyzed from the database acquired during three long-term campaigns carried out on the Gironde/Garonne estuary. We have shown that in the upper estuary the tidal bore intensity is mainly governed by the local dimensionless tide amplitude ε. The bore intensity is an increasing function of ε and this relationship does not depend on freshwater

  19. The origin of neap-spring tidal cycles

    Science.gov (United States)

    Kvale, E.P.

    2006-01-01

    The origin of oceanic tides is a basic concept taught in most introductory college-level sedimentology/geology, oceanography, and astronomy courses. Tides are typically explained in the context of the equilibrium tidal theory model. Yet this model does not take into account real tides in many parts of the world. Not only does the equilibrium tidal model fail to explicate amphidromic circulation, it also does not explain diurnal tides in low latitude positions. It likewise fails to explain the existence of tide-dominated areas where neap-spring cycles are synchronized with the 27.32-day orbital cycle of the Moon (tropical month), rather than with the more familiar 29.52-day cycle of lunar phases (synodic month). Both types of neap-spring cycles can be recognized in the rock record. A complete explanation of the origin of tides should include a discussion of dynamic tidal theory. In the dynamic tidal model, tides resulting from the motions of the Moon in its orbit around the Earth and the Earth in its orbit around the Sun are modeled as products of the combined effects of a series of phantom satellites. The movement of each of these satellites, relative to the Earth's equator, creates its own tidal wave that moves around an amphidromic point. Each of these waves is referred to as a tidal constituent. The geometries of the ocean basins determine which of these constituents are amplified. Thus, the tide-raising potential for any locality on Earth can be conceptualized as the result of a series of tidal constituents specific to that region. A better understanding of tidal cycles opens up remarkable opportunities for research on tidal deposits with implications for, among other things, a more complete understanding of the tidal dynamics responsible for sediment transport and deposition, changes in Earth-Moon distance through time, and the possible influences tidal cycles may exert on organisms. ?? 2006 Elsevier B.V. All rights reserved.

  20. Inorganic Nitrate Promotes the Browning of White Adipose Tissue through the Nitrate-Nitrite-Nitric Oxide Pathway

    Science.gov (United States)

    Roberts, Lee D; Ashmore, Tom; Kotwica, Aleksandra O; Murfitt, Steven A; Fernandez, Bernadette O; Feelisch, Martin; Griffin, Julian L

    2015-01-01

    Inorganic nitrate was once considered an oxidation end-product of nitric oxide metabolism with little biological activity. However, recent studies have demonstrated that dietary nitrate can modulate mitochondrial function in man and is effective in reversing features of the metabolic syndrome in mice. Using a combined histological, metabolomics, and transcriptional and protein analysis approach we mechanistically define that nitrate not only increases the expression of thermogenic genes in brown-adipose tissue but also induces the expression of brown adipocyte-specific genes and proteins in white adipose tissue, substantially increasing oxygen consumption and fatty acid β-oxidation in adipocytes. Nitrate induces these phenotypic changes through a mechanism distinct from known physiological small molecule activators of browning, the recently identified nitrate-nitrite-nitric oxide pathway. The nitrate-induced browning effect was enhanced in hypoxia, a serious co-morbidity affecting white adipose tissue in obese individuals, and corrected impaired brown adipocyte-specific gene expression in white adipose tissue in a murine model of obesity. Since resulting beige/brite cells exhibit anti-obesity and anti-diabetic effects, nitrate may be an effective means of inducing the browning response in adipose tissue to treat the metabolic syndrome. PMID:25249574

  1. Classification of tidal inlets along the Central east coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Reddy, N.A.; Vikas, M.; Rao, S.; JayaKumar S.

    ) as long as the alongshore sediment bypasses the tidal inlet. Classification of coastal systems in a broader view is necessary for the management of tidal inlets. There are several methods to classify tidal inlets based on different perspectives namely geo...

  2. European brown hare syndrome virus in free-ranging European brown hares from Argentina

    DEFF Research Database (Denmark)

    Frolich, K.; Kujawski, G.E.J.G.; Rudolph, M.

    2003-01-01

    From 1998 to 2000, serum samples of 80 shot European brown hares (Lepus europaeus) from Argentina were examined for antibodies against European brown hare syndrome virus (EBHSV) and 80 spleen samples were tested for EBHSV-antigen by enzyme linked immunosorbent assay (ELISA). Nine hares were posit...... in these hares. This is the first report of antibodies to EBHSV, EBHSV-antigen, and electron microscopy findings in free-ranging European brown hares from South America....

  3. Storage stability of flour-blasted brown rice

    Science.gov (United States)

    Brown rice was blasted with rice flour rather than sand in a sand blaster to make microscopic nicks and cuts so that water can easily penetrate into the brown rice endosperm and cook the rice in a shorter time. The flour-blasted American Basmati brown rice, long grain brown rice, and parboiled long...

  4. Time scales in tidal disruption events

    Directory of Open Access Journals (Sweden)

    Krolik J.

    2012-12-01

    Full Text Available We explore the temporal structure of tidal disruption events pointing out the corresponding transitions in the lightcurves of the thermal accretion disk and of the jet emerging from such events. The hydrodynamic time scale of the disrupted star is the minimal time scale of building up the accretion disk and the jet and it sets a limit on the rise time. This suggest that Swift J1644+57, that shows several flares with a rise time as short as a few hundred seconds could not have arisen from a tidal disruption of a main sequence star whose hydrodynamic time is a few hours. The disrupted object must have been a white dwarf. A second important time scale is the Eddington time in which the accretion rate changes form super to sub Eddington. It is possible that such a transition was observed in the light curve of Swift J2058+05. If correct this provides interesting constraints on the parameters of the system.

  5. Tidal instability in exoplanetary systems evolution

    Directory of Open Access Journals (Sweden)

    Le Gal P.

    2011-02-01

    Full Text Available A new element is proposed to play a role in the evolution of extrasolar planetary systems: the tidal (or elliptical instability. It comes from a parametric resonance and takes place in any rotating fluid whose streamlines are (even slightly elliptically deformed. Based on theoretical, experimental and numerical works, we estimate the growth rate of the instability for hot-jupiter systems, when the rotation period of the star is known. We present the physical process, its application to stars, and preliminary results obtained on a few dozen systems, summarized in the form of a stability diagram. Most of the systems are trapped in the so-called "forbidden zone", where the instability cannot grow. In some systems, the tidal instability is able to grow, at short timescales compared to the system evolution. Implications are discussed in the framework of misaligned transiting systems, as the rotational axis of the star would be unstable in systems where this elliptical instability grows.

  6. Tidal conversion by a knife-edge

    Science.gov (United States)

    Llewellyn Smith, S. G.; Young, W. R.

    2003-04-01

    We obtain an analytic solution for the generation of internal gravity waves by tidal flow past a vertical barrier of height b in a uniformly stratified ocean of depth h>b and buoyancy frequency N. If b/h is small and N is constant, the radiated power (watts per metre of barrier) is (pi/4) ρ_0 b^2 U^2 N sqrt{1-(f/ω)^2} where ρ_0 is the mean density of seawater, U \\cos (ω t) the incident tidal velocity, and f the Coriolis frequency. The radiated power increases rapidly with b/h; as b/h to 1 the radiated power diverges as ln[(h-b)/b]. By solving an integral equation numerically, we calculate the conversion in a realistically stratified ocean in which the buoyancy frequency increases by a factor of fifty between the abyss and the thermocline. The radiated power is greater by a factor of about three than that of a uniformly stratified ocean with N equal to the vertically averaged buoyancy frequency.

  7. Tidal Dwarf Galaxies and Missing Baryons

    Directory of Open Access Journals (Sweden)

    Frederic Bournaud

    2010-01-01

    Full Text Available Tidal dwarf galaxies form during the interaction, collision, or merger of massive spiral galaxies. They can resemble “normal” dwarf galaxies in terms of mass, size, and become dwarf satellites orbiting around their massive progenitor. They nevertheless keep some signatures from their origin, making them interesting targets for cosmological studies. In particular, they should be free from dark matter from a spheroidal halo. Flat rotation curves and high dynamical masses may then indicate the presence of an unseen component, and constrain the properties of the “missing baryons,” known to exist but not directly observed. The number of dwarf galaxies in the Universe is another cosmological problem for which it is important to ascertain if tidal dwarf galaxies formed frequently at high redshift, when the merger rate was high, and many of them survived until today. In this paper, “dark matter” is used to refer to the nonbaryonic matter, mostly located in large dark halos, that is, CDM in the standard paradigm, and “missing baryons” or “dark baryons” is used to refer to the baryons known to exist but hardly observed at redshift zero, and are a baryonic dark component that is additional to “dark matter”.

  8. Angular momentum transport by tidal acoustic wave

    International Nuclear Information System (INIS)

    Sakurai, T.

    1976-01-01

    An analytical expression of the braking torque on a Jacobian ellipsoid rotating steadily in an enviromental gas is given, based on the assumption that the ellipsoid rotates around its shortest principal axis with an angular momentum slightly larger than that at the bifurcation point of the Maclaurin spheroid. This braking torque is effected by the gravitational interaction between the ellipsoid matter and a spiral density configuration in the environmental gas. This spiral configuration which is called a tidal acoustic wave, is caused by the zone of silence effect in a supersonic flow. With respect to a coordinates system rotating with the ellipsoid, a supersonic region appears outside a certain radius. In this supersonic region, the effect of the non-axisymmetric fluctuation in the ellipsoid potential propagates along the downstream branches of the Mach waves. This one-sided response of the supersonic part causes the tidal acoustic wave. The discussion is restricted to the equatorial plane, and an acoustic approximation of the basic equations is used under the assumption that the self-gravity effect of the environmental gas is negligable in comparison to the main gravity of the ellipsoid. The results are applied to the pre- and post-Main sequence phases of a rotating star, and relating astrophysical problems are discussed. (Auth.)

  9. Angular momentum transport by tidal acoustic wave

    Energy Technology Data Exchange (ETDEWEB)

    Sakurai, T [Kyoto Univ. (Japan). Faculty of Engineering

    1976-05-01

    An analytical expression of the braking torque on a Jacobian ellipsoid rotating steadily in an enviromental gas is given, based on the assumption that the ellipsoid rotates around its shortest principal axis with an angular momentum slightly larger than that at the bifurcation point of the Maclaurin spheroid. This braking torque is effected by the gravitational interaction between the ellipsoid matter and a spiral density configuration in the environmental gas. This spiral configuration which is called a tidal acoustic wave, is caused by the zone of silence effect in a supersonic flow. With respect to a coordinates system rotating with the ellipsoid, a supersonic region appears outside a certain radius. In this supersonic region, the effect of the non-axisymmetric fluctuation in the ellipsoid potential propagates along the downstream branches of the Mach waves. This one-sided response of the supersonic part causes the tidal acoustic wave. The discussion is restricted to the equatorial plane, and an acoustic approximation of the basic equations is used under the assumption that the self-gravity effect of the environmental gas is negligable in comparison to the main gravity of the ellipsoid. The results are applied to the pre- and post-Main sequence phases of a rotating star, and relating astrophysical problems are discussed.

  10. Production of fine coke from brown coal

    Energy Technology Data Exchange (ETDEWEB)

    Koenigs, H B

    1977-08-01

    The coke supply of the iron and steel industry, the design, function, and special features of the open-hearth are described, including coking properties and applications of the culm coke produced from brown coal. (In German)

  11. Browning phenomenon of medieval stained glass windows.

    Science.gov (United States)

    Ferrand, Jessica; Rossano, Stéphanie; Loisel, Claudine; Trcera, Nicolas; van Hullebusch, Eric D; Bousta, Faisl; Pallot-Frossard, Isabelle

    2015-04-07

    In this work, three pieces of historical on-site glass windows dated from the 13th to 16th century and one archeological sample (8th century) showing Mn-rich brown spots at their surface or subsurface have been characterized by optical microscopy and Scanning Electron Microscopy coupled with Energy Dispersive X-ray spectroscopy. The oxidation state of Mn as well as the Mn environment in the alteration phase have been characterized by X-ray absorption spectroscopy at the Mn K-edge. Results show that the oxidation state of Mn and therefore the nature of the alteration phase varies according to the sample considered and is correlated with the extent of the brown alteration. The larger the brown areas the more oxidized the Mn. However, by contrast with literature, the samples presenting the more extended brown areas are not similar to pyrolusite and contain Mn mainly under a (+III) oxidation state.

  12. Microlensing Binaries with Candidate Brown Dwarf Companions

    DEFF Research Database (Denmark)

    Shin, I.-G; Han, C.; Gould, A.

    2012-01-01

    masses of the brown dwarf companions are 0.02 ± 0.01 M⊙ and 0.019 ± 0.002 M⊙ for MOA-2011-BLG-104/OGLE-2011-BLG-0172 and MOA-2011-BLG-149, respectively, and both companions are orbiting low-mass M dwarf host stars. More microlensing brown dwarfs are expected to be detected as the number of lensing events...

  13. Morphodynamics of the Manyema tidal delta 1 LIST OF TABLES ...

    African Journals Online (AJOL)

    Kheira Kortenbout

    Morphodynamics of the Manyema tidal delta. 1. LIST OF ... Location of Manyema Creek and its associated tidal delta platform at Kunduchi. Fig. 2. ... platform. Beachcomber. Hotel. Whitesands. Hotel. Kunduchi. Beach Hotel. Giraffe. Hotel. INDIAN. OCEAN. Mombasa. Dar es. Salaam. KUNDUCHI. KENYA. TANZANIA.

  14. Anomaly Detection Techniques for the Condition Monitoring of Tidal Turbines

    Science.gov (United States)

    2014-09-29

    turbine design includes many horizontal and vertical axis solutions, some with major structural and operational variations (Aly & El-Hawary, 2011...However, a common focus is the horizontal axis design, holding many similarities with a standard wind turbine . Maintenance on tidal turbines ...However, despite similarities between tidal and wind power turbine design, the operating environment is vastly different. Water is over 800 times

  15. Tidal bending of glaciers: a linear viscoelastic approach

    DEFF Research Database (Denmark)

    Reeh, Niels; Christensen, Erik Lintz; Mayer, Christoph

    2003-01-01

    In theoretical treatments of tidal bending of floating glaciers, the glacier is usually modelled as an elastic beam with uniform thickness, resting on an elastic foundation. With a few exceptions, values of the elastic (Young's) modulus E of ice derived from tidal deflection records of floating...

  16. Flow and sediment transport in an Indonesian tidal network

    NARCIS (Netherlands)

    Buschman, F.A.

    2011-01-01

    The Berau river, situated in east Kalimantan (Indonesia), drains a relatively small catchment area and splits into several interconnected tidal channels. This tidal network connects to the sea. The sea is host to extremely diverse coral reef communities. Also the land side of the region is

  17. Water and suspended sediment division at a stratified tidal junction

    NARCIS (Netherlands)

    Buschman, F.A.; Vegt, van der M.; Hoitink, A.J.F.; Hoekstra, P.

    2013-01-01

    [1] Tidal junctions play a crucial role in the transport of water, salt, and sediment through a delta distributary network. Water, salt and sediment are exchanged at tidal junctions, thereby influencing the transports in the connecting branches and the overall dynamics of the system. This paper

  18. Water and suspended sediment division at a stratified tidal junction

    NARCIS (Netherlands)

    Buschman, F.A.; Vegt, M. van der; Hoitink, A.J.F.; Hoekstra, P.

    2013-01-01

    Tidal junctions play a crucial role in the transport of water, salt, and sediment through a delta distributary network. Water, salt and sediment are exchanged at tidal junctions, thereby influencing the transports in the connecting branches and the overall dynamics of the system. This paper

  19. Detecting areal changes in tidal flats after sea dike construction ...

    Indian Academy of Sciences (India)

    The main objective of this study was to estimate changes in the area of tidal flats that occurred after sea dike construction on the western coast of South Korea using Landsat-TM images. Applying the ISODATA method of unsupervised classification for Landsat-TM images, the tidal flats were identified, and the resulting areas ...

  20. 33 CFR 117.181 - Oakland Inner Harbor Tidal Canal.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Oakland Inner Harbor Tidal Canal. 117.181 Section 117.181 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY... Tidal Canal. The draws of the Alameda County highway drawbridges at Park Street, mile 5.2; Fruitvale...

  1. Relation between tidal damping and wave celerity in estuaries

    NARCIS (Netherlands)

    Savenije, H.H.G.; Veling, E.J.M.

    2005-01-01

    Observations in estuaries indicate that an amplified tidal wave moves considerably faster than is indicated by the classical equation for wave propagation. Similarly, the celerity of propagation is lower if the tidal wave is damped. This phenomenon is clearly observed in the Schelde estuary (located

  2. Potential sites for tidal power in New Jersey.

    Science.gov (United States)

    2014-04-01

    High-resolution simulation is made to model tidal energy along the coastlines of New Jersey (NJ) and its neighbor states with an : unprecedentedly fine grid. On the basis of the simulation, a thorough search is made for sites for tidal power generati...

  3. Ammonium transformation in a nitrogen-rich tidal freshwater marsh

    DEFF Research Database (Denmark)

    Gribsholt, B.; Andersson, M.; Boschker, H.T.S.

    2006-01-01

    The fate and transport of watershed-derived ammonium in a tidal freshwater marsh fringing the nutrient rich Scheldt River, Belgium, was quantified in a whole ecosystem 15N labeling experiment. In late summer (September) we added 15N-NH4+ to the flood water entering a 3477 m2 tidal freshwater marsh...

  4. Tidal power - a major prospect for the 21st century

    International Nuclear Information System (INIS)

    Haws, E.T.

    1997-01-01

    Tidal power technology is reviewed and its prospects for the next century assessed. It is concluded that the technology is now in place and, given the political will to secure financing, tidal power offers a clean, renewable and sustainable source of power for the near future. (UK)

  5. Wave and tidal generation devices reliability and availability

    CERN Document Server

    Tavner, Peter John

    2017-01-01

    To some extent the wave and tidal generation industry is following in the wake of the wind industry, learning from the growing experience of offshore wind farm deployment. This book combines wind industry lessons with wave and tidal field knowledge to explore the main reliability and availability issues facing this growing industry.

  6. Temporal bed level variations in the Yangtze tidal flats (abstract)

    NARCIS (Netherlands)

    Yan, H.; Van Prooijen, B.C.

    2013-01-01

    The Yangtze River is one of the largest rivers in the world and the longest one in Asia. Its estuary forms an important entrance for shipping, but is also a key ecological system. Especially the inter-tidal flats are valuable habitats. The health and integrity of the estuarine tidal flat are however

  7. Land Use in Korean Tidal Wetlands: Impacts and Management Strategies

    Science.gov (United States)

    Hong, Sun-Kee; Koh, Chul-Hwan; Harris, Richard R.; Kim, Jae-Eun; Lee, Jeom-Sook; Ihm, Byung-Sun

    2010-05-01

    The coastal landscapes in southwestern Korea include a diverse array of tidal wetlands and salt marshes. These coastal zones link the ecological functions of marine tidal wetlands and freshwater ecosystems with terrestrial ecosystems. They are rich in biological diversity and play important roles in sustaining ecological health and processing environmental pollutants. Korean tidal wetlands are particularly important as nurseries for economically important fishes and habitats for migratory birds. Diking, draining, tourism, and conversion to agricultural and urban uses have adversely affected Korean tidal wetlands. Recent large development projects have contributed to further losses. Environmental impact assessments conducted for projects affecting tidal wetlands and their surrounding landscapes should be customized for application to these special settings. Adequate environmental impact assessments will include classification of hydrogeomorphic units and consideration of their responses to biological and environmental stressors. As is true worldwide, Korean laws and regulations are changing to be more favorable to the conservation and protection of tidal wetlands. More public education needs to be done at the local level to build support for tidal wetland conservation. Some key public education points include the role of tidal wetlands in maintaining healthy fish populations and reducing impacts of nonpoint source pollution. There is also a need to develop procedures for integrating economic and environmental objectives within the overall context of sustainable management and land uses.

  8. Are Wave and Tidal Energy Plants New Green Technologies?

    Science.gov (United States)

    Douziech, Mélanie; Hellweg, Stefanie; Verones, Francesca

    2016-07-19

    Wave and tidal energy plants are upcoming, potentially green technologies. This study aims at quantifying their various potential environmental impacts. Three tidal stream devices, one tidal range plant and one wave energy harnessing device are analyzed over their entire life cycles, using the ReCiPe 2008 methodology at midpoint level. The impacts of the tidal range plant were on average 1.6 times higher than the ones of hydro-power plants (without considering natural land transformation). A similar ratio was found when comparing the results of the three tidal stream devices to offshore wind power plants (without considering water depletion). The wave energy harnessing device had on average 3.5 times higher impacts than offshore wind power. On the contrary, the considered plants have on average 8 (wave energy) to 20 (tidal stream), or even 115 times (tidal range) lower impact than electricity generated from coal power. Further, testing the sensitivity of the results highlighted the advantage of long lifetimes and small material requirements. Overall, this study supports the potential of wave and tidal energy plants as alternative green technologies. However, potential unknown effects, such as the impact of turbulence or noise on marine ecosystems, should be further explored in future research.

  9. Tidal and gravity waves study from the airglow measurements at ...

    Indian Academy of Sciences (India)

    The other waves may be the upward propagating gravity waves or waves resulting from the interaction of inter-mode tidal oscillations, interaction of tidal waves with planetary waves and gravity waves. Some times, the second harmonic wave has higher vertical velocity than the corresponding fundamental wave. Application ...

  10. Seasonal behaviour of tidal inlets in a tropical monsoon area

    NARCIS (Netherlands)

    Lam, N.T.; Stive, M.J.F.; Verhagen, H.J.; Wang, Z.B.

    2008-01-01

    Morphodynamics of a tidal inlet system on a micro-tidal coast in a tropical monsoon influenced region is modelled and discussed. Influences of river flow and wave climate on the inlet morphology are investigated with the aid of process-based state-of-the-art numerical models. Seasonal and episodic

  11. On the superposition of bedforms in a tidal channel

    DEFF Research Database (Denmark)

    Winter, C; Vittori, G.; Ernstsen, V.B.

    2008-01-01

    High resolution bathymetric measurements reveal the super-imposition of bedforms in the Grådyb tidal inlet in the Danish Wadden Sea. Preliminary results of numerical model simulations are discussed: A linear stability model was tested to explain the large bedforms as being caused by tidal system ...

  12. Satellite tidal magnetic signals constrain oceanic lithosphere-asthenosphere boundary

    DEFF Research Database (Denmark)

    Grayver, Alexander V.; Schnepf, Neesha R.; Kuvshinov, Alexey V.

    2016-01-01

    The tidal flow of electrically conductive oceans through the geomagnetic field results in the generation ofsecondary magnetic signals, which provide information on the subsurface structure. Data from the new generation of satellites were shown to contain magnetic signals due to tidal flow; howeve...

  13. TIDAL STIRRING OF SATELLITES WITH SHALLOW DENSITY PROFILES PREVENTS THEM FROM BEING TOO BIG TO FAIL

    Energy Technology Data Exchange (ETDEWEB)

    Tomozeiu, Mihai; Mayer, Lucio [Institute for Computational Science, University of Zurich, Winterthurerstrasse 190, CH-8057 Zürich (Switzerland); Quinn, Thomas, E-mail: mihai@physik.uzh.ch [Astronomy Department, University of Washington, Box 351580, Seattle, WA 98195 (United States)

    2016-08-10

    The “too big to fail” problem is revisited by studying the tidal evolution of populations of dwarf satellites with different density profiles. The high-resolution cosmological ΛCDM “ErisMod” set of simulations is used. These simulations can model both the stellar and dark matter components of the satellites, and their evolution under the action of the tides of a Milky Way (MW)-sized host halo at a force resolution better than 10 pc. The stronger tidal mass loss and re-shaping of the mass distribution induced in satellites with γ = 0.6 dark matter density distributions, as those resulting from the effect of feedback in hydrodynamical simulations of dwarf galaxy formation, are sufficient to bring the circular velocity profiles in agreement with the kinematics of MW’s dSphs. In contrast, in simulations in which the satellites retain cusps at z = 0 there are several “massive failures” with circular velocities in excess of the observational constraints. Various sources of deviations in the conventionally adopted relation between the circular velocity at the half-light radius and the one-dimensional line of sight velocity dispersions are found. Such deviations are caused by the response of circular velocity profiles to tidal effects, which also varies depending on the initially assumed inner density profile and by the complexity of the stellar kinematics, which include residual rotation and anisotropy. In addition, tidal effects naturally induce large deviations in the stellar mass–halo mass relation for halo masses below 10{sup 9} M {sub ⊙}, preventing any reliable application of the abundance matching technique to dwarf galaxy satellites.

  14. Admiralty Inlet Pilot Tidal Project Final Technical Report

    Energy Technology Data Exchange (ETDEWEB)

    Collar, Craig [Public Utility District No. 1 of Snohomish County, Everett, WA (United States)

    2015-09-14

    This document represents the final report for the Admiralty Inlet Pilot Tidal Project, located in Puget Sound, Washington, United States. The Project purpose was to license, permit, and install a grid-connected deep-water tidal turbine array (two turbines) to be used as a platform to gather operational and environmental data on tidal energy generation. The data could then be used to better inform the viability of commercial tidal energy generation from technical, economic, social, and environmental standpoints. This data would serve as a critical step towards the responsible advancement of commercial scale tidal energy in the United States and around the world. In late 2014, Project activities were discontinued due to escalating costs, and the DOE award was terminated in early 2015. Permitting, licensing, and engineering design activities were completed under this award. Final design, deployment, operation, and monitoring were not completed. This report discusses the results and accomplishments achieved under the subject award.

  15. Tidal Forces in Dyonic Reissner-Nördstrom Black Hole

    Science.gov (United States)

    Sharif, M.; Kousar, Lubna

    2018-03-01

    This paper investigates the tidal as well as magnetic charge effects produced in dyonic Reissner-Nordström black hole. We evaluate Newtonian radial acceleration using radial geodesics for freely falling test particles. We establish system of equations governing radial and angular tidal forces using geodesic deviation equation and discuss their solutions for bodies falling freely towards this black hole. The radial tidal force turns out to be compressing outside the event horizon whereas the angular tidal force changes sign between event and Cauchy horizons unlike Schwarzschild black hole. The radial geodesic component starts decreasing in dyonic Reissner-Nordström black hole unlike Schwarzschild case. We conclude that magnetic charge strongly affects the radial as well as angular components of tidal force.

  16. Understanding the Influence of Retention Basin on Tidal Dynamics in Tidal Estuaries

    Science.gov (United States)

    Kumar, Mohit; Schuttelaars, Henk; Roos, Pieter

    2014-05-01

    Both the tidal motion and suspended sediment concentration (SSC) in tidal embayments and estuaries are influenced by anthropogenic (e.g. deepening ) and natural changes. An example of such an estuary is the Ems estuary, situated on the border of the Netherlands and Germany. The mean tidal range towards the end of the Ems estuary has increased from 1.5m in the 1950s to more than 3m in the 1990s while the suspended concentration has increased by a factor 10. To possibly reduce these negative effects, the construction of retention basin(s) (RB) is considered. In this contribution, the influence of location and geometry of RBs on tidal dynamics and SSC is investigated. For this purpose, a three-dimensional semi-analytic idealized model is developed. This model is an extension of the model proposed by Winant (2007) to arbitrary domain and realistic bathymetry with partial slip boundary condition at the bottom. The sea surface elevation (SSE) is calculated numerically using a finite element method. Next, the three-dimensional velocities are calculated by combining the analytically calculated vertical profiles and the gradients of the SSE which are obtained numerically. Firstly, the influence of a RB on the tidal dynamics in an infinitely long, rectangular, frictionless estuary is considered. The SSE decreases when the RB is located between a node and a landward antinode, consistent with the work of Alebregtse et al. (2013). Secondly, an estuary of finite length is connected to a sea. By varying the width of the sea, not only the effect of the distance of the RB to the landward end plays a role, but also the distance to the open sea becomes important. Finally, we discuss the influence of a RB on the tidal motion and initial sediment transport, considering the Ems estuary with realistic bathymetry. Results show that the SSE at the landward end of the Ems estuary decreases for all locations of the RBs. This decrease is most pronounced for the RB which is closest to the end

  17. Fine sediment transport into the hyperturbid lower Ems River : The role of channel deepening and sediment-induced drag reduction

    NARCIS (Netherlands)

    Van Maren, D.S.; Winterwerp, J.C.; Vroom, J.

    2015-01-01

    Deepening of estuarine tidal channels often leads to tidal amplification and increasing fine sediment import. Increasing fine sediment import, in turn, may lower the hydraulic drag (due to a smoother muddy bed and/or sediment-induced damping of turbulence), and therefore, further strengthen tidal

  18. ADD1/SREBP1c activates the PGC1-alpha promoter in brown adipocytes

    DEFF Research Database (Denmark)

    Hao, Qin; Hansen, Jacob B; Petersen, Rasmus K

    2010-01-01

    Cold adaptation elicits a paradoxical simultaneous induction of fatty acid synthesis and beta-oxidation in brown adipose tissue. We show here that cold exposure coordinately induced liver X receptor alpha (LXRalpha), adipocyte determination and differentiation-dependent factor 1 (ADD1)/sterol...

  19. Aspects of growth, recruitment and conservation of the Brown Mussel Perna perna along the Tsitsikamma Coast

    Directory of Open Access Journals (Sweden)

    R. J. M Crawford

    1983-12-01

    Full Text Available Beds of brown mussels Perna perna are a dominant feature of the lower tidal range of rocky shores in the Tsitsikamma Coastal National Park. Mussels in this region attain a length of 30-40 mm by the end of their first year, and the majority probably exceed 50 mm at two years of age. Secondary settlement of plantigrades occurs from midspring through early winter, especially in summer and early autumn, and growth of adult forms is slowest prior to this settlement. Settlement occurs serially and powerful cohorts may be formed. At Nature's Valley density and biomass of mussels inside the park's boundary are significantly higher than in non-protected areas. Older age groups are also more abundant within the park.

  20. Hunting promotes sexual conflict in brown bears.

    Science.gov (United States)

    Gosselin, Jacinthe; Leclerc, Martin; Zedrosser, Andreas; Steyaert, Sam M J G; Swenson, Jon E; Pelletier, Fanie

    2017-01-01

    The removal of individuals through hunting can destabilize social structure, potentially affecting population dynamics. Although previous studies have shown that hunting can indirectly reduce juvenile survival through increased sexually selected infanticide (SSI), very little is known about the spatiotemporal effects of male hunting on juvenile survival. Using detailed individual monitoring of a hunted population of brown bears (Ursus arctos) in Sweden (1991-2011), we assessed the spatiotemporal effect of male removal on cub survival. We modelled cub survival before, during and after the mating season. We used three proxies to evaluate spatial and temporal variation in male turnover; distance and timing of the closest male killed and number of males that died around a female's home range centre. Male removal decreased cub survival only during the mating season, as expected in seasonal breeders with SSI. Cub survival increased with distance to the closest male killed within the previous 1·5 years, and it was lower when the closest male killed was removed 1·5 instead of 0·5 year earlier. We did not detect an effect of the number of males killed. Our results support the hypothesis that social restructuring due to hunting can reduce recruitment and suggest that the distribution of the male deaths might be more important than the overall number of males that die. As the removal of individuals through hunting is typically not homogenously distributed across the landscape, spatial heterogeneity in hunting pressure may cause source-sink dynamics, with lower recruitment in areas of high human-induced mortality. © 2016 The Authors. Journal of Animal Ecology published by John Wiley & Sons Ltd on behalf of British Ecological Society.

  1. Meteorologies of brown dwarfs and extrasolar giant planets

    Science.gov (United States)

    Cooper, Curtis Steven

    2006-06-01

    This dissertation explores the consequences of atmospheric dynamics for observations of substellar mass objects (SMOs). Discussed first is the growth of cloud particles of various compositions in brown dwarfs of different surface gravities and effective temperatures. The structure of these objects is calculated with a one-dimensional radiative transfer model. To determine particle sizes, the timescales for microphysical growth processes, including nucleation, coagulation, and coalescence, are compared to the timescale for gravitational sedimentation. The model also allows for sustained uplifting of condensable vapor in convective regions. The results show that particle sizes vary greatly over the range of objects studied. In most cases, clouds on brown dwarfs do not dominate the opacity. Rather, they smooth the emergent spectrum and partially redistribute the radiative energy. The focus then shifts to extrasolar giant planets (EGPs). Results are presented from a three-dimensional model of atmospheric dynamics on the transiting Jupiter-like planet HD 209458b. As a close-in orbiter (known as a "roaster"), HD 209458b is super-heated on its dayside. Due to tidal locking of the interior, the dayside hemisphere faces the star in perpetuity, which leads to very different dynamics than is seen on Jupiter. The flow is characterized by an eastward supersonic jet ( u ~ 4 kms - 1 ) extending from the equator to the mid-latitudes. Temperature contrasts are ~500 K at the photosphere. At 220 mbar, winds blow the hottest regions downstream from the substellar point by ~60°, with direct implications for the infrared light curve. These simulations are extended to the study of carbon chemistry in HD 209458b's atmosphere by coupling the CO/CH 4 reaction kinetics to the dynamics. Disequilibrium results from slow reaction rates at low temperatures and pressures. Effective vertical quenching near the ~3 bar level leads to uniformly high concentrations of CO at the photosphere, even in

  2. Spin-orbital Tidal Dynamics and Tidal Heating in the TRAPPIST-1 Multiplanet System

    Science.gov (United States)

    Makarov, Valeri V.; Berghea, Ciprian T.; Efroimsky, Michael

    2018-04-01

    We perform numerical simulations of the TRAPPIST-1 system of seven exoplanets orbiting a nearby M dwarf, starting with a previously suggested stable configuration. The long-term stability of this configuration is confirmed, but the motion of planets is found to be chaotic. The eccentricity values are found to vary within finite ranges. The rates of tidal dissipation and tidal evolution of orbits are estimated, assuming an Earth-like rheology for the planets. We find that under this assumption, the planets b, d, and e were captured in the 3:2 or higher spin–orbit resonances during the initial spin-down, but slipped further down into the 1:1 resonance. Depending on its rheology, the innermost planet b may be captured in a stable pseudosynchronous rotation. Nonsynchronous rotation ensures higher levels of tidal dissipation and internal heating. The positive feedback between the viscosity and the dissipation rate—and the ensuing runaway heating—are terminated by a few self-regulation processes. When the temperature is high and the viscosity is low enough, the planet spontaneously leaves the 3:2 resonance. Further heating is stopped either by passing the peak dissipation or by the emergence of partial melt in the mantle. In the post-solidus state, the tidal dissipation is limited to the levels supported by the heat transfer efficiency. The tides on the host star are unlikely to have had a significant dynamical impact. The tides on the synchronized inner planets tend to reduce these planets’ orbital eccentricity, possibly contributing thereby to the system’s stability.

  3. A improved tidal method without water level

    Science.gov (United States)

    Luo, xiaowen

    2017-04-01

    Now most tide are obtained use water Level and pressure type water gage, but it is difficult to install them and reading is in low accuracy in this method . In view of above-mentioned facts, In order to improve tide accuracy, A improved method is introduced.sea level is obtained in given time using high-precision GNSS buoy combined instantaneous position from pressure gage. two steps are as following, (1) the GNSS time service is used as the source of synchronization reference in tidal measurement; (2) centimeter-level sea surface positions are obtained in real time using difference GNSS The improved method used in seafloor topography survey,in 145 cross points, 95% meet the requirements of the Hydrographic survey specification. It is effective method to obtain higher accuracy tide.

  4. Design and optimization of tidal turbine airfoil

    Energy Technology Data Exchange (ETDEWEB)

    Grasso, F. [ECN Wind Energy, Petten (Netherlands)

    2011-07-15

    In order to increase the ratio of energy capture to the loading and thereby to reduce cost of energy, the use of specially tailored airfoils is needed. This work is focused on the design of an airfoil for marine application. Firstly, the requirements for this class of airfoils are illustrated and discussed with reference to the requirements for wind turbine airfoils. Then, the design approach is presented. This is a numerical optimization scheme in which a gradient based algorithm is used, coupled with RFOIL solver and a composite Bezier geometrical parameterization. A particularly sensitive point is the choice and implementation of constraints; in order to formalize in the most complete and effective way the design requirements, the effects of activating specific constraints are discussed. Particularly importance is given to the cavitation phenomenon. Finally, a numerical example regarding the design of a high efficiency, tidal turbine airfoil is illustrated and the results are compared with existing turbine airfoils.

  5. Assimilating data into open ocean tidal models

    Science.gov (United States)

    Kivman, Gennady A.

    The problem of deriving tidal fields from observations by reason of incompleteness and imperfectness of every data set practically available has an infinitely large number of allowable solutions fitting the data within measurement errors and hence can be treated as ill-posed. Therefore, interpolating the data always relies on some a priori assumptions concerning the tides, which provide a rule of sampling or, in other words, a regularization of the ill-posed problem. Data assimilation procedures used in large scale tide modeling are viewed in a common mathematical framework as such regularizations. It is shown that they all (basis functions expansion, parameter estimation, nudging, objective analysis, general inversion, and extended general inversion), including those (objective analysis and general inversion) originally formulated in stochastic terms, may be considered as utilizations of one of the three general methods suggested by the theory of ill-posed problems. The problem of grid refinement critical for inverse methods and nudging is discussed.

  6. Will Restored Tidal Marshes Be Sustainable?

    Directory of Open Access Journals (Sweden)

    Michelle Orr

    2003-10-01

    Full Text Available We assess whether or not restored marshes in the San Francisco Estuary are expected to be sustainable in light of future landscape scale geomorphic processes given typical restored marsh conditions. Our assessment is based on a review of the literature, appraisal of monitoring data for restored marshes, and application of vertical accretion modeling of organic and inorganic sedimentation. Vertical accretion modeling suggests that salt marshes in San Pablo Bay will be sustainable for moderate relative sea level rise (3 to 5 mm yr-1 and average sediment supply (c. 100 mg L-1. Accelerated relative sea level rise (above 6 mm yr-1 and/or reduced sediment supply (50 mg L-1 will cause lowering of the marsh surface relative to the tide range and may cause shifts from high to low marsh vegetation by the year 2100. Widespread conversion of marsh to mudflat-"ecological drowning"-is not expected within this time frame. Marshes restored at lower elevations necessary to aid the natural development of channel systems (c. 0.5 m below mean higher high water are predicted to accrete to high marsh elevations by the year 2100 for moderate relative sea level rise and sediment supply conditions. Existing rates of sediment accretion in restored fresh water tidal marshes of the Delta of greater than 9 mm yr-1 and slightly lower drowning elevations suggest that these marshes will be resilient against relatively high rates of sea level rise. Because of higher rates of organic production, fresh water marshes are expected to be less sensitive to reduced sediment availability than salt marshes. The ultimate long-term threat to the sustainability of tidal marshes is the interruption of coastal rollover-the process by which landward marsh expansion in response to sea level rise compensates for shoreline erosion. Bay front development now prevents most landward marsh expansion, while shoreline erosion is expected to accelerate as sea level rises.

  7. TIDALLY DRIVEN DYNAMOS IN A ROTATING SPHERE

    International Nuclear Information System (INIS)

    Cébron, D.; Hollerbach, R.

    2014-01-01

    Large-scale planetary or stellar magnetic fields generated by a dynamo effect are mostly attributed to flows forced by buoyancy forces in electrically conducting fluid layers. However, these large-scale fields may also be controlled by tides, as previously suggested for the star τ-boo, Mars, or the early Moon. By simulating a small local patch of a rotating fluid, Barker and Lithwick have recently shown that tides can drive small-scale dynamos by exciting a hydrodynamic instability, the so-called elliptical (or tidal) instability. By performing global magnetohydrodynamic simulations of a rotating spherical fluid body, we investigate if this instability can also drive the observed large-scale magnetic fields. We are thus interested in the dynamo threshold and the generated magnetic field in order to test if such a mechanism is relevant for planets and stars. Rather than solving the problem in a geometry deformed by tides, we consider a spherical fluid body and add a body force to mimic the tidal deformation in the bulk of the fluid. This allows us to use an efficient spectral code to solve the magnetohydrodynamic problem. We first compare the hydrodynamic results with theoretical asymptotic results and numerical results obtained in a truly deformed ellipsoid, which confirms the presence of elliptical instability. We then perform magnetohydrodynamic simulations and investigate the dynamo capability of the flow. Kinematic and self-consistent dynamos are finally simulated, showing that the elliptical instability is capable of generating a dipole-dominated large-scale magnetic field in global simulations of a fluid rotating sphere

  8. Dwarf Galaxies Swimming in Tidal Tails

    Science.gov (United States)

    2005-01-01

    This false-color infrared image from NASA's Spitzer Space Telescope shows little 'dwarf galaxies' forming in the 'tails' of two larger galaxies that are colliding together. The big galaxies are at the center of the picture, while the dwarfs can be seen as red dots in the red streamers, or tidal tails. The two blue dots above the big galaxies are stars in the foreground. Galaxy mergers are common occurrences in the universe; for example, our own Milky Way galaxy will eventually smash into the nearby Andromeda galaxy. When two galaxies meet, they tend to rip each other apart, leaving a trail, called a tidal tail, of gas and dust in their wake. It is out of this galactic debris that new dwarf galaxies are born. The new Spitzer picture demonstrates that these particular dwarfs are actively forming stars. The red color indicates the presence of dust produced in star-forming regions, including organic molecules called polycyclic aromatic hydrocarbons. These carbon-containing molecules are also found on Earth, in car exhaust and on burnt toast, among other places. Here, the molecules are being heated up by the young stars, and, as a result, shine in infrared light. This image was taken by the infrared array camera on Spitzer. It is a 4-color composite of infrared light, showing emissions from wavelengths of 3.6 microns (blue), 4.5 microns (green), 5.8 microns (orange), and 8.0 microns (red). Starlight has been subtracted from the orange and red channels in order to enhance the dust features.

  9. Ambient Noise in an Urbanized Tidal Channel

    Science.gov (United States)

    Bassett, Christopher

    In coastal environments, when topographic and bathymetric constrictions are combined with large tidal amplitudes, strong currents (> 2 m/s) can occur. Because such environments are relatively rare and difficult to study, until recently, they have received little attention from the scientific community. However, in recent years, interest in developing tidal hydrokinetic power projects in these environments has motivated studies to improve this understanding. In order to support an analysis of the acoustic effects of tidal power generation, a multi-year study was conducted at a proposed project site in Puget Sound (WA) are analyzed at a site where peak currents exceeded 3.5 m/s. From these analyses, three noise sources are shown to dominate the observed variability in ambient noise between 0.02-30 kHz: anthropogenic noise from vessel traffic, sediment-generated noise during periods of strong currents, and flow-noise resulting from turbulence advected over the hydrophones. To assess the contribution of vessel traffic noise, one calendar year of Automatic Identification System (AIS) ship-traffic data was paired with hydrophone recordings. The study region included inland waters of the Salish Sea within a 20 km radius of the hydrophone deployment site in northern Admiralty Inlet. The variability in spectra and hourly, daily, and monthly ambient noise statistics for unweighted broadband and M-weighted sound pressure levels is driven largely by vessel traffic. Within the one-year study period, at least one AIS transmitting vessel is present in the study area 90% of the time and over 1,363 unique vessels are recorded. A noise budget for vessels equipped with AIS transponders identifies cargo ships, tugs, and passenger vessels as the largest contributors to noise levels. A simple model to predict received levels at the site based on an incoherent summation of noise from different vessel types yields a cumulative probability density function of broadband sound pressure

  10. Tidal River Management (TRM and Tidal Basin Management (TBM: A case study on Bangladesh

    Directory of Open Access Journals (Sweden)

    Talchabhadel Rocky

    2016-01-01

    Full Text Available Bangladesh is the biggest delta of the world. Construction of numbers of polders is one of the flood resilient approach. But the presence of coastal polders de-linked the flood plain. The siltation in river causes riverbeds to become higher than the adjacent crop lands, and vast area under the polders became permanently water logged rendering large tract of land uncultivable. The current practice is temporarily de-poldering by cutting embankment. This is a natural water management process with very little human interventions but it needs strong participation and consensus with a great deal of sacrifice by the stakeholders for a specific period (3 to 5 years or even more[1]. An attempt has been made to study the phenomena of tidal basin management reviewing some secondary data and processes involved in successfully operated tidal basins of Bangladesh. And preliminary laboratory experiments are carried out to precisely look into the suspended sediment transport. With varying outflow discharge and sediment supply, the transport processes are investigated. 3D sediment transport model developed using openFOAM has good agreement with experimental result and can be used to better understand effectiveness of tidal basin management.

  11. Consideration of tidal influences in determining measurement periods when monitoring built-environment radon levels

    International Nuclear Information System (INIS)

    Crockett, R.G.M.; Phillips, P.S.; Gillmore, G.K.; Denman, A.R.; Groves-Kirkby, C.J.

    2006-01-01

    Using three hourly-sampling continuous radon monitors, deployed at separate locations in and around the town of Northampton, UK, during the period May 2002 to September 2005, evidence has been identified of tidal influences on built environment radon levels. The data-sets from these deployments, together with additional data-sets collected from a house in Devon, UK, over the period May 1994 to October 1996, and made available by the UK Building Research Establishment, have been analysed using a number of analytical techniques, including a novel correlation technique developed during the investigation. Radon concentration levels in all of the investigated sites exhibit cyclic variation with a period of approximately 14-15 days, equivalent to the spring-tide interval, and lag the corresponding new and full moons by varying periods. The tide/radon lag interval for the two public-sector buildings changes abruptly in September/October, indicating that a significant characteristic of these buildings changes at this time. For domestic properties, the lag is relatively unchanged during the year, but is greater in Devon, in the South-West of England, than in Northampton, in the English East Midlands. These differences are attributed to location relative to coastlines (the South-West experiences greater tidal-loading than the Midlands), underlying geology and rock/soil hydration. Depending on its position within the local 14 to 15-day tidally-induced radon cycle, an individual 7-day radon measurement may yield an erroneous estimate of longer term average levels, up to 46% higher or lower than the average level for one of the reported data-sets. Thus a building with a mean radon concentration below the local Action Level could appear to be unsafe if measured around a tidal-cyclic radon maximum: conversely, a building with a mean radon concentration above the Action Level could appear to be safe when measured around a tidal-cyclic radon minimum. A minimum radon

  12. Pollution induced tidal variability in water quality of Mahim Estuary

    Digital Repository Service at National Institute of Oceanography (India)

    Zingde, M.D.; Sabnis, M.M.

    Variability of water quality due to release of wastewater in Mahim Estuary (Maharashtra, India) and associated nearshore waters is discussed. The mixing of low salinity contaminated estuary water with high salinity bay water was considerably...

  13. Assessment of tidal circulation and tidal current asymmetry in the Iroise sea with specific emphasis on characterization of tidal energy resources around the Ushant Island.

    Science.gov (United States)

    Thiébaut, Maxime; Sentchev, Alexei

    2015-04-01

    We use the current velocity time series recorded by High Frequency Radars (HFR) to study circulation in highly energetic tidal basin - the Iroise sea. We focus on the analysis of tidal current pattern around the Ushant Island which is a promising site of tidal energy. The analysis reveals surface current speeds reaching 4 m/s in the North of Ushant Island and in the Fromveur Strait. In these regions 1 m/s is exceeded 60% of time and up to 70% of time in center of Fromveur. This velocity value is particularly interesting because it represents the cut-in-speed of the most of marine turbine devices. Tidal current asymmetry is not always considered in tidal energy site selection. However, this quantity plays an important role in the quantification of hydrokinetic resources. Current velocity times series recorded by HFR highlights the existence of a pronounced asymmetry in current magnitude between the flood and ebb tide ranging from -0.5 to more 2.5. Power output of free-stream devices depends to velocity cubed. Thus a small current asymmetry can generate a significant power output asymmetry. Spatial distribution of asymmetry coefficient shows persistent pattern and fine scale structure which were quantified with high degree of accuracy. The particular asymmetry evolution on both side of Fromveur strait is related to the spatial distribution of the phase lag of the principal semi-diurnal tidal constituent M2 and its higher order harmonics. In Fromveur, the asymmetry is reinforced due to the high velocity magnitude of the sixth-diurnal tidal harmonics. HF radar provides surface velocity speed, however the quantification of hydrokinetic resources has to take into account the decreasing of velocity with depth. In order to highlight this phenomenon, we plot several velocity profiles given by an ADCP which was installed in the HFR study area during the same period. The mean velocity in the water column calculated by using the ADCP data show that it is about 80% of the

  14. Spectroscopic, scanning laser OBIC, and I-V/QE characterizations of browned EVA solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Pern, F.J. [National Renewable Energy Lab., Golden, CO (United States); Eisgruber, I.L. [Materials Research Group, Inc., Wheat Ridge, CO (United States); Micheels, R.H. [Polestar Technologies, Inc., Needham Hts, MA (United States)

    1996-05-01

    The effects of ethylene-vinyl acetate (EVA) discoloration due to accelerated field or laboratory exposure on the encapsulated silicon (Si) solar cells or EVA/glass laminates were characterized quantitatively by using non-invasive, non-destructive ultraviolet-visible (UV-vis) spectrophotometry, spectrocolorimetry, spectrofluorometry, scanning laser OBIC (optical beam induced current) spectroscopy, and current-voltage (I-V) and quantum efficiency (QE) measurements. The results show that the yellowness index (YI) measured directly over the AR-coated solar cells under the glass superstrate increased from the range of -80 to -90 to the range of -20 to 15 as the EVA changed from clear to brown. The ratio of two fluorescence emission peak areas generally increased from 1.45 to 5.69 as browning increased, but dropped to 4.21 on a darker EVA. For a solar cell with brown EVA in the central region, small-area grating QE measurements and scanning laser OBIC analysis between the brown and clear EVA regions showed that the quantum efficiency loss at 633 nm was 42%-48% of the loss at 488 nm, due to a reduced decrease of transmittance in browned EVA at the longer wavelengths. The portion of the solar cell under the browned EVA showed a decrease of {approximately}36% in efficiency, as compared to the cell efficiency under clear EVA. Transmittance loss at 633 nm was 38% of the loss at 488 nm for a light yellow-brown EVA/glass laminate that showed a small increase of 10 in the yellowness index.

  15. Characterization of the central neural projections to brown, white, and beige adipose tissue.

    Science.gov (United States)

    Wiedmann, Nicole M; Stefanidis, Aneta; Oldfield, Brian J

    2017-11-01

    The functional recruitment of classic brown adipose tissue (BAT) and inducible brown-like or beige fat is, to a large extent, dependent on intact sympathetic neural input. Whereas the central neural circuits directed specifically to BAT or white adipose tissue (WAT) are well established, there is only a developing insight into the nature of neural inputs common to both fat types. Moreover, there is no clear view of the specific central and peripheral innervation of the browned component of WAT: beige fat. The objective of the present study is to examine the neural input to both BAT and WAT in the same animal and, by exposing different cohorts of rats to either thermoneutral or cold conditions, define changes in central neural organization that will ensure that beige fat is appropriately recruited and modulated after browning of inguinal WAT (iWAT). At thermoneutrality, injection of the neurotropic (pseudorabies) viruses into BAT and WAT demonstrates that there are dedicated axonal projections, as well as collateral axonal branches of command neurons projecting to both types of fat. After cold exposure, central neural circuits directed to iWAT showed evidence of reorganization with a greater representation of command neurons projecting to both brown and beiged WAT in hypothalamic (paraventricular nucleus and lateral hypothalamus) and brainstem (raphe pallidus and locus coeruleus) sites. This shift was driven by a greater number of supraspinal neurons projecting to iWAT under cold conditions. These data provide evidence for a reorganization of the nervous system at the level of neural connectivity following browning of WAT.-Wiedmann, N. M., Stefanidis, A., Oldfield, B. J. Characterization of the central neural projections to brown, white, and beige adipose tissue. © FASEB.

  16. Derivation of Delaware Bay tidal parameters from space shuttle photography

    International Nuclear Information System (INIS)

    Zheng, Quanan; Yan, Xiaohai; Klemas, V.

    1993-01-01

    The tide-related parameters of the Delaware Bay are derived from space shuttle time-series photographs. The water areas in the bay are measured from interpretation maps of the photographs with a CALCOMP 9100 digitizer and ERDAS Image Processing System. The corresponding tidal levels are calculated using the exposure time annotated on the photographs. From these data, an approximate function relating the water area to the tidal level at a reference point is determined. Based on the function, the water areas of the Delaware Bay at mean high water (MHW) and mean low water (MLW), below 0 m, and for the tidal zone are inferred. With MHW and MLW areas and the mean tidal range, the authors calculate the tidal influx of the Delaware Bay, which is 2.76 x 1O 9 m 3 . Furthermore, the velocity of flood tide at the bay mouth is determined using the tidal flux and an integral of the velocity distribution function at the cross section between Cape Henlopen and Cape May. The result is 132 cm/s, which compares well with the data on tidal current charts

  17. Vertical Distribution of Tidal Flow Reynolds Stress in Shallow Sea

    Institute of Scientific and Technical Information of China (English)

    SONG Zhi-yao; NI Zhi-hui; LU Guo-nian

    2009-01-01

    Based on the results of the tidal flow Reynolds stresses of the field observations,indoor experiments,and numerical models,the parabolic distribution of the tidal flow Reynolds stress is proposed and its coefficients are determined theoretically in this paper.Having been well verified with the field data and experimental data,the proposed distribution of Reynolds stress is also compared with numerical model results,and a good agreement is obtained,showing that this distribution can well reflect the basic features of Reynolds stress deviating from the linear distribution that is downward when the tidal flow is of acceleration,upward when the tidal flow is of deceleration.Its dynamics cause is also discussed preliminarily and the influence of the water depth is pointed out from the definition of Reynolds stress,turbulent generation,transmission,and so on.The established expression for the vertical distribution of the tidal flow Reynolds stress is not only simple and explicit,but can also well reflect the features of the tidal flow acceleration and deceleration for further study on the velocity profile of tidal flow.

  18. Diurnal, semidiurnal, and fortnightly tidal components in orthotidal proglacial rivers.

    Science.gov (United States)

    Briciu, Andrei-Emil

    2018-02-22

    The orthotidal rivers are a new concept referring to inland rivers influenced by gravitational tides through the groundwater tides. "Orthotidal signals" is intended to describe tidal signals found in inland streamwaters (with no oceanic input); these tidal signals were locally generated and then exported into streamwaters. Here, we show that orthotidal signals can be found in proglacial rivers due to the gravitational tides affecting the glaciers and their surrounding areas. The gravitational tides act on glacier through earth and atmospheric tides, while the subglacial water is affected in a manner similar to the groundwater tides. We used the wavelet analysis in order to find tidally affected streamwaters. T_TIDE analyses were performed for discovering the tidal constituents. Tidal components with 0.95 confidence level are as follows: O1, PI1, P1, S1, K1, PSI1, M2, T2, S2, K2, and MSf. The amplitude of the diurnal tidal constituents is strongly influenced by the daily thermal cycle. The average amplitude of the semidiurnal tidal constituents is less altered and ranges from 0.0007 to 0.0969 m. The lunisolar synodic fortnightly oscillation, found in the time series of the studied river gauges, is a useful signal for detecting orthotidal rivers when using noisier data. The knowledge of the orthotidal oscillations is useful for modeling fine resolution changes in rivers.

  19. [Characteristics of tidal breathing pulmonary function in children with tracheobronchomalacia].

    Science.gov (United States)

    Li, Lan; Chen, Qaing; Zhang, Fan; Zhu, Shuang-Gui; Hu, Ci-Lang; Wu, Ai-Min

    2017-12-01

    To investigate the characteristics of tidal breathing pulmonary function in children with tracheobronchomalacia (TBM). In this study, 30 children who were diagnosed with TBM using electronic bronchoscopy were enrolled in the observation group; 30 healthy children were recruited in the normal control group. For individuals in each group, the assessment of tidal breath pulmonary function was performed at diagnosis and 3, 6, 9, and 12 months after diagnosis. There were no significant differences in tidal volume, inspiratory time, expiratory time, and inspiratory to expiratory ratio between the two groups (P>0.05). Compared with the control group, the observation group had a significantly higher respiratory rate and significantly lower ratio of time to peak tidal expiratory flow to total expiratory time (TPTEF/TE) and ratio of volume to peak tidal expiratory flow to total expiratory volume (VPTEF/VE). There was a time-dependent increase in TPTEF/TE and VPTEF/VE for TBM children from the time of initial diagnosis to 12 months after diagnosis. Tidal breathing pulmonary function has characteristic changes in children with TBM. Tidal breathing pulmonary function tends to be recovered with increased age in children with TBM.

  20. Device interactions in reducing the cost of tidal stream energy

    International Nuclear Information System (INIS)

    Vazquez, A.; Iglesias, G.

    2015-01-01

    Highlights: • Numerical modelling is used to estimate the levelised cost of tidal stream energy. • As a case study, a model of Lynmouth (UK) is implemented and successfully validated. • The resolution of the model allows the demarcation of individual devices on the model grid. • Device interactions reduce the available tidal resource and the cost increases significantly. - Abstract: The levelised cost of energy takes into account the lifetime generated energy and the costs associated with a project. The objective of this work is to investigate the effects of device interactions on the energy output and, therefore, on the levelised cost of energy of a tidal stream project, by means of numerical modelling. For this purpose, a case study is considered: Lynmouth (North Devon, UK), an area in the Bristol Channel in which the first tidal stream turbine was installed − a testimony of its potential as a tidal energy site. A state-of-the-art hydrodynamics model is implemented on a high-resolution computational grid, which allows the demarcation of the individual devices. The modification to the energy output resulting from interaction between turbines within the tidal farm is thus resolved for each individual turbine. The results indicate that significant changes in the levelised cost of energy values, of up to £0.221 kW h −1 , occur due to the aforementioned modifications, which should not be disregarded if the cost of tidal stream energy is to be minimised

  1. Large tidal plants may supply 1,000 TWh / year

    International Nuclear Information System (INIS)

    Lemperiere, F.

    2006-10-01

    Many studies of tidal plants have been made fifty years ago: they were usually devoted to sites with average tidal head over 6 m and reduced works at sea: estuaries such as La Rance (France) or Severn (U.K.) were favoured: preferred corresponding operation was using flow from a high basin to low sea level, supplying power 4 hours from 12. Such solutions had 2 drawbacks: power supply poorly adapted to needs and modified shore tidal ecosystems. Beyond that the power cost was usually higher than from thermal plants and very few plants were built, the main one being the Rance plant in France supplying 0,5 TWh/year with 240 MW. The world theoretical tidal potential is in the same range as the traditional hydropower potential. A new approach of tidal plants based upon solutions existing now and using new operating methods substantiates the possibility of over 1,000 TWh/year of cost efficient tidal energy with limited environmental impact and power supply well adapted to requirements. Over 15 countries may be involved. Tidal plants with heads as low as 4 m may be cost efficient. (author)

  2. Tidal day organic and inorganic material flux of ponds in the Liberty Island freshwater tidal wetland.

    Science.gov (United States)

    Lehman, Peggy W; Mayr, Shawn; Liu, Leji; Tang, Alison

    2015-01-01

    The loss of inorganic and organic material export and habitat produced by freshwater tidal wetlands is hypothesized to be an important contributing factor to the long-term decline in fishery production in San Francisco Estuary. However, due to the absence of freshwater tidal wetlands in the estuary, there is little information on the export of inorganic and organic carbon, nutrient or phytoplankton community biomass and the associated mechanisms. A single-day study was conducted to assess the potential contribution of two small vegetated ponds and one large open-water pond to the inorganic and organic material flux within the freshwater tidal wetland Liberty Island in San Francisco Estuary. The study consisted of an intensive tidal day (25.5 h) sampling program that measured the flux of inorganic and organic material at three ponds using continuous monitoring of flow, chlorophyll a, turbidity and salt combined with discrete measurements of phytoplankton community carbon, total and dissolved organic carbon and nutrient concentration at 1.5 h intervals. Vegetated ponds had greater material concentrations than the open water pond and, despite their small area, contributed up to 81% of the organic and 61% of the inorganic material flux of the wetland. Exchange between ponds was important to wetland flux. The small vegetated pond in the interior of the wetland contributed as much as 72-87% of the total organic carbon and chlorophyll a and 10% of the diatom flux of the wetland. Export of inorganic and organic material from the small vegetated ponds was facilitated by small-scale topography and tidal asymmetry that produced a 40% greater material export on ebb tide. The small vegetated ponds contrasted with the large open water pond, which imported 29-96% of the inorganic and 4-81% of the organic material into the wetland from the adjacent river. This study identified small vegetated ponds as an important source of inorganic and organic material to the wetland and the

  3. Activation of classical brown adipocytes in the adult human perirenal depot is highly correlated with PRDM16-EHMT1 complex expression.

    Directory of Open Access Journals (Sweden)

    Gaku Nagano

    Full Text Available Brown fat generates heat to protect against cold and obesity. Adrenergic stimulation activates the thermogenic program of brown adipocytes. Although the bioactivity of brown adipose tissue in adult humans had been assumed to very low, several studies using positron emission tomography-computed tomography (PET-CT have detected bioactive brown adipose tissue in adult humans under cold exposure. In this study, we collected adipose tissues obtained from the perirenal regions of adult patients with pheochromocytoma (PHEO or non-functioning adrenal tumors (NF. We demonstrated that perirenal brown adipocytes were activated in adult patients with PHEO. These cells had the molecular characteristics of classical brown fat rather than those of beige/brite fat. Expression of brown adipose tissue markers such as uncoupling protein 1 (UCP1 and cell death-inducing DFFA-like effector A (CIDEA was highly correlated with the amounts of PRD1-BF-1-RIZ1 homologous domain-containing protein-16 (PRDM16 - euchromatic histone-lysine N-methyltransferase 1 (EHMT1 complex, the key transcriptional switch for brown fat development. These results provide novel insights into the reconstruction of human brown adipocytes and their therapeutic application against obesity and its complications such as type 2 diabetes.

  4. A Summary of the San Francisco Tidal Wetlands Restoration Series

    Directory of Open Access Journals (Sweden)

    Larry R. Brown

    2003-10-01

    Full Text Available The four topical articles of the Tidal Wetlands Restoration Series summarized and synthesized much of what is known about tidal wetlands and tidal wetland restoration in the San Francisco Estuary (hereafter “Estuary”. Despite a substantial amount of available information, major uncertainties remain. A major uncertainty with regard to fishes is the net benefit of restored tidal wetlands relative to other habitats for native fishes in different regions of the Estuary given the presence of numerous invasive alien species. With regard to organic carbon, a major uncertainty is the net benefit of land use change given uncertainty about the quantity and quality of different forms of organic carbon resulting from different land uses. A major challenge is determining the flux of organic carbon from open systems like tidal wetlands. Converting present land uses to tidal wetlands will almost certainly result in increased methylation of mercury at the local scale with associated accumulation of mercury within local food webs. However, it is unclear if such local accumulation is of concern for fish, wildlife or humans at the local scale or if cumulative effects at the regional scale will emerge. Based on available information it is expected that restored tidal wetlands will remain stable once constructed; however, there is uncertainty associated with the available data regarding the balance of sediment accretion, sea-level rise, and sediment erosion. There is also uncertainty regarding the cumulative effect of many tidal restoration projects on sediment supply. The conclusions of the articles highlight the need to adopt a regional and multidisciplinary approach to tidal wetland restoration in the Estuary. The Science Program of the CALFED effort provides an appropriate venue for addressing these issues.

  5. Evaluation of streambed scour at bridges over tidal waterways in Alaska

    Science.gov (United States)

    Conaway, Jeffrey S.; Schauer, Paul V.

    2012-01-01

    The potential for streambed scour was evaluated at 41 bridges that cross tidal waterways in Alaska. These bridges are subject to several coastal and riverine processes that have the potential, individually or in combination, to induce streambed scour or to damage the structure or adjacent channel. The proximity of a bridge to the ocean and water-surface elevation and velocity data collected over a tidal cycle were criteria used to identify the flow regime at each bridge, whether tidal, riverine, or mixed, that had the greatest potential to induce streambed scour. Water-surface elevations measured through at least one tide cycle at 32 bridges were correlated to water levels at the nearest tide station. Asymmetry of the tidal portion of the hydrograph during the outgoing tide at 12 bridges indicated that riverine flows were stored upstream of the bridge during the tidal exchange. This scenario results in greater discharges and velocities during the outgoing tide compared to those on the incoming tide. Velocity data were collected during outgoing tides at 10 bridges that experienced complete flow reversals, and measured velocities during the outgoing tide exceeded the critical velocity required to initiate sediment transport at three sites. The primary risk for streambed scour at most of the sites considered in this study is from riverine flows rather than tidal fluctuations. A scour evaluation for riverine flow was completed at 35 bridges. Scour from riverine flow was not the primary risk for six tidally-controlled bridges and therefore not evaluated at those sites. Field data including channel cross sections, a discharge measurement, and a water-surface slope were collected at the 35 bridges. Channel instability was identified at 14 bridges where measurable scour and or fill were noted in repeated surveys of channel cross sections at the bridge. Water-surface profiles for the 1-percent annual exceedance probability discharge were calculated by using the Hydrologic

  6. Cyclic PaO2 oscillations assessed in the renal microcirculation: correlation with tidal volume in a porcine model of lung lavage.

    Science.gov (United States)

    Thomas, Rainer; Möllmann, Christian; Ziebart, Alexander; Liu, Tanghua; David, Matthias; Hartmann, Erik K

    2017-07-11

    Oscillations of the arterial partial pressure of oxygen induced by varying shunt fractions occur during cyclic alveolar recruitment within the injured lung. Recently, these were proposed as a pathomechanism that may be relevant for remote organ injury following acute respiratory distress syndrome. This study examines the transmission of oxygen oscillations to the renal tissue and their tidal volume dependency. Lung injury was induced by repetitive bronchoalveolar lavage in eight anaesthetized pigs. Cyclic alveolar recruitment was provoked by high tidal volume ventilation. Oscillations of the arterial partial pressure of oxygen were measured in real-time in the macrocirculation by multi-frequency phase fluorimetry and in the renal microcirculation by combined white-light spectrometry and laser-Doppler flowmetry during tidal volume down-titration. Significant respiratory-dependent oxygen oscillations were detected in the macrocirculation and transmitted to the renal microcirculation in a substantial extent. The amplitudes of these oscillations significantly correlate to the applied tidal volume and are minimized during down-titration. In a porcine model oscillations of the arterial partial pressure of oxygen are induced by cyclic alveolar recruitment and transmitted to the renal microcirculation in a tidal volume-dependent fashion. They might play a role in organ crosstalk and remote organ damage following lung injury.

  7. Bars and spirals in tidal interactions with an ensemble of galaxy mass models

    Science.gov (United States)

    Pettitt, Alex R.; Wadsley, J. W.

    2018-03-01

    We present simulations of the gaseous and stellar material in several different galaxy mass models under the influence of different tidal fly-bys to assess the changes in their bar and spiral morphology. Five different mass models are chosen to represent the variety of rotation curves seen in nature. We find a multitude of different spiral and bar structures can be created, with their properties dependent on the strength of the interaction. We calculate pattern speeds, spiral wind-up rates, bar lengths, and angular momentum exchange to quantify the changes in disc morphology in each scenario. The wind-up rates of the tidal spirals follow the 2:1 resonance very closely for the flat and dark matter-dominated rotation curves, whereas the more baryon-dominated curves tend to wind-up faster, influenced by their inner bars. Clear spurs are seen in most of the tidal spirals, most noticeable in the flat rotation curve models. Bars formed both in isolation and interactions agree well with those seen in real galaxies, with a mixture of `fast' and `slow' rotators. We find no strong correlation between bar length or pattern speed and the interaction strength. Bar formation is, however, accelerated/induced in four out of five of our models. We close by briefly comparing the morphology of our models to real galaxies, easily finding analogues for nearly all simulations presenter here, showing passages of small companions can easily reproduce an ensemble of observed morphologies.

  8. Tidal energy UK Government R and D programme. Final report

    International Nuclear Information System (INIS)

    Craig, J.W.; Davies, L.M.; Allington, M.A.

    1996-05-01

    The United Kingdom Government's research programme into the feasibility of exploiting tidal power for electricity generation in Britain's estuaries is described in this document. The history of the research is included from the Severn Barrage Committee in 1978 to the conclusion of the tidal energy barrages programme in 1994. The programme sought to reduce uncertainty on costs, technical performance and environmental and regional effects, in order to firm up on decisions on whether to construct certain specific barrages. It was concluded that, while technically feasible, tidal power from barrages, was and will continue to be uneconomic compared with other energy sources. Other renewable technologies would receive further research. (UK)

  9. Virtual Seafloor Reduces Internal Wave Generation by Tidal Flow

    Science.gov (United States)

    Zhang, Likun; Swinney, Harry L.

    2014-03-01

    Our numerical simulations of tidal flow of a stratified fluid over periodic knife-edge ridges and random topography reveal that the time-averaged tidal energy converted into internal gravity wave radiation arises only from the section of a ridge above a virtual seafloor. The average radiated power is approximated by the power predicted by linear theory if the height of the ridge is measured relative to the virtual floor. The concept of a virtual floor can extend the applicability of linear theory to global predictions of the conversion of tidal energy into internal wave energy in the oceans.

  10. Assessment of Kinetic Tidal Energy Resources Using SELFE

    OpenAIRE

    Manasa Ranjan Behera; Pavel Tkalich

    2014-01-01

    An investigation is carried out to study the theoretical tidal stream energy resource in the Singapore Strait to support the search for renewable energy in the effort to reduce the carbon footprints in the Southeast Asia. The tidal hydrodynamics in the Singapore Strait has been simulated using a Semi-implicit Eulerian-Lagrangian Finite-Element (SELFE) model solving the 3D shallow water equations with Boussinesq approximations. Potential sites, with high tidal current (2.5 m/s) and suitable fo...

  11. Geometric properties of hydraulic-relevant tidal bedforms

    DEFF Research Database (Denmark)

    Winter, Christian; Ferret, Yann; Lefebvre, Alice

    2013-01-01

    of bedform genesis and dynamics is not yet available, various empirical descriptors have been formulated based on extensive data compilations (e.g. Allen, 1968; Flemming, 1988; Francken, 2004). Mean bedform heights H and lengths L were found to scale, e.g H = a * L b in which a=0.03-0.07 and b=0.7-0.9. Due...... on the tidal stage: Whereas the secondary bedforms act as roughness elements throughout the tidal cycle, the large primary bedforms dominate the hydraulics when the tidal flow is in the (dominant) direction of the bedform orientation (e.g. ebb-directed primary bedforms act during ebb currents) when...

  12. The dependence of galaxy clustering on tidal environment in the Sloan Digital Sky Survey

    Science.gov (United States)

    Paranjape, Aseem; Hahn, Oliver; Sheth, Ravi K.

    2018-06-01

    The influence of the Cosmic Web on galaxy formation and evolution is of great observational and theoretical interest. We investigate whether the Cosmic Web leaves an imprint in the spatial clustering of galaxies in the Sloan Digital Sky Survey (SDSS), using the group catalogue of Yang et al. and tidal field estimates at ˜2 h-1 Mpc scales from the mass-tides-velocity data set of Wang et al. We use the tidal anisotropy α (Paranjape et al.) to characterize the tidal environment of groups, and measure the redshift-space 2-point correlation function (2pcf) of group positions and the luminosity- and colour-dependent clustering of group galaxies using samples segregated by α. We find that all the 2pcf measurements depend strongly on α, with factors of ˜20 between the large-scale 2pcf of objects in the most and least isotropic environments. To test whether these strong trends imply `beyond halo mass' effects for galaxy evolution, we compare our results with corresponding 2pcf measurements in mock catalogues constructed using a halo occupation distribution that uses only halo mass as an input. We find that this prescription qualitatively reproduces all observed trends, and also quantitatively matches many of the observed results. Although there are some statistically significant differences between our `halo mass only' mocks and the data - in the most and least isotropic environments - which deserve further investigation, our results suggest that if the tidal environment induces additional effects on galaxy properties other than those inherited from their host haloes, then these must be weak.

  13. Analysis of Tidal Data for Dagang Tidal Gauge and Study of the Changes for the National Height Datum

    Directory of Open Access Journals (Sweden)

    WU Fumei

    2015-07-01

    Full Text Available The main tides affecting Dagang sea level are analyzed and the national height datum is studied by analyzing 1980—2011 hourly tidal data and 1952—2007 monthly mean tidal data. Firstly, the frequencies and amplitudes of main tides including 180 short-period tides and 6 long-period tides are gained by the Fouirer transform. Then the actual amplitudes and their variations of main tides are obtained by the harmonic analysis of the 1980—2011 hourly tidal data, and the changes with about 19 year period can easily be found in the amplitudes of Q1、O1、M2、K1、K2. And then the changes of the mean sea level at Dagang tidal gauge defining national height datum during the period of 1952—2011 are studied by the harmonic analysis and the shifting average of 18.61 year tidal heights. The results of these methods show that the mean sea level at Dagang tidal gauge descended with the speed of 1.07 mm/a and 0.76 mm/a respectively during 1952—1980, and that it ascended with the speed of 1.59 mm/a and 1.62 mm/a respectively during 1980—2011. And finally the difference of 0.14 cm is achieved by the shifting average of 18.61 year tidal heights for 1985 National Height Datum.

  14. Properties of sorbents from brown coal

    Energy Technology Data Exchange (ETDEWEB)

    Straka, P.; Buchtele, J. [Academy of Sciences of the Czech Republic, Prague (Czech Republic)

    2000-07-01

    The surface and sorptional properties of carbonaceous materials prepared from brown coal and their relation to minerals content and coal bulk density as technologically important parameters of starting coal were described. Chars were prepared from brown coal of North Bohemian Brown Coal District and activated with CO{sub 2} in a large-scale laboratory unit. Their surface and sorptive properties were investigated. It was found that mineral matter/ash content favourably affects the mesoporosity development in chars/activated chars as the sorption capacity increased with increasing ash content in chars. No influence of ash content on the macroporosity was observed. With the activated chars, both the inner surface and sorption capacity showed the maximum in the burn-off range of 41-64%. Optimization of the process is discussed.

  15. Linking freshwater tidal hydrology to carbon cycling in bottomland hardwood wetlands

    Science.gov (United States)

    Carl C. Trettin; Brooke J. Czwartacki; Craig J. Allan; Devendra M. Amatya

    2016-01-01

    Hydrology is recognized as one of the principal factors regulating soil biogeochemical processes in forested wetlands. However, the consequences of tidally mediated hydrology are seldom considered within forested wetlands that occur along tidal water bodies. These tidal water bodies may be either fresh or brackish, and the tidal streams function as a reservoir to...

  16. MicroRNA-133 Controls Brown Adipose Determination in Skeletal Muscle Satellite Cells by Targeting Prdm16

    DEFF Research Database (Denmark)

    Yin, Hang; Pasut, Alessandra; Soleimani, Vahab D

    2013-01-01

    Brown adipose tissue (BAT) is an energy-dispensing thermogenic tissue that plays an important role in balancing energy metabolism. Lineage-tracing experiments indicate that brown adipocytes are derived from myogenic progenitors during embryonic development. However, adult skeletal muscle stem cells...... (satellite cells) have long been considered uniformly determined toward the myogenic lineage. Here, we report that adult satellite cells give rise to brown adipocytes and that microRNA-133 regulates the choice between myogenic and brown adipose determination by targeting the 3'UTR of Prdm16. Antagonism...... of microRNA-133 during muscle regeneration increases uncoupled respiration, glucose uptake, and thermogenesis in local treated muscle and augments whole-body energy expenditure, improves glucose tolerance, and impedes the development of diet-induced obesity. Finally, we demonstrate that miR-133 levels...

  17. The radius anomaly in the planet/brown dwarf overlapping mass regime

    Directory of Open Access Journals (Sweden)

    Baraffe I.

    2011-02-01

    Full Text Available The recent detection of the transit of very massive substellar companions (Deleuil et al. 2008; Bouchy et al. 2010; Anderson et al. 2010; Bakos et al. 2010 provides a strong constraint to planet and brown dwarf formation and migration mechanisms. Whether these objects are brown dwarfs originating from the gravitational collapse of a dense molecular cloud that, at the same time, gave birth to the more massive stellar companion, or whether they are planets that formed through core accretion of solids in the protoplanetary disk can not always be determined unambiguously and the mechanisms responsible for their short orbital distances are not yet fully understood. In this contribution, we examine the possibility to constrain the nature of a massive substellar object from the various observables provided by the combination of Radial Velocity and Photometry measurements (e.g. Mp , Rp , M⋆, Age, a, e.... In a second part, developments in the modeling of tidal evolution at high eccentricity and inclination - as measured for HD 80 606 with e = 0.9337 (Naef et al. 2001 , XO-3 with a stellar obliquity ε⋆  > 37.3 ± 3.7 deg (Hébrard et al. 2008; Winn et al. 2009 and several other exoplanets - are discussed along with their implication in the understanding of the radius anomaly problem of extrasolar giant planets.

  18. Briquetting of Coke-Brown Coal Mixture

    Directory of Open Access Journals (Sweden)

    Ïurove Juraj

    1998-09-01

    Full Text Available The paper presents the results of the research of briquetting a coke-brown coal composite The operation consists of the feeding crushed coal and coke to moulds and pressing into briquettes which have been made in the Laboratories at the Mining Faculty of Technical University of Košice (Slovakia. In this research, all demands will be analyzed including the different aspects of the mechanical quality of briquettes, the proportion of fine pulverulent coal and coke in bricks, the requirements for briquetting the coke-brown coal materials.

  19. Fuel briquettes from brown coals of Yakutia

    Energy Technology Data Exchange (ETDEWEB)

    L.A. Nikolaeva; V.G. Latyshev; O.N. Burenina [Russian Academy of Sciences, Yakutsk (Russian Federation). Institute of Oil and Gas Problems

    2009-04-15

    Experimental data on the development of technology for the manufacture of briquetted fuel from brown coals with the use of various petroleum binders are presented. The influence of the moisture content, the coal particle-size composition, the binder type and concentration, the compacting pressure, and heat treatment regimes on the mechanical properties of the materials was studied. The optimal compositions and optimal values of the engineering parameters for the production of graded briquetted fuel from brown coals of the Kangalassy deposit in the Republic of Sakha (Yakutia) were established.

  20. Brown tumor of mandible with primary hyperparathyroidism

    International Nuclear Information System (INIS)

    Ali, S.K.; Khan, F.A.; Siddiq, A.; Hanif, M.S.

    2011-01-01

    Parathyroid hormone (PTH) is secreted and released by the parathyroid glands, the activity of which is controlled by the ionized serum calcium level. Increased PTH secretion results in hyperparathyroidism. Hyperparathyroidism is classified as primary, secondary and tertiary types. Primary hyperparathyroidism is characterized by increased parathyroid hormone secretion occurring as a result of abnormality in one or more of the parathyroid glands. Brown tumors are non-neoplastic lesions as a result of abnormal bone metabolism in cases of hyperparathyroidism, creating a local destructive phenomenon. A rare case of a young female patient with brown tumors in her mandible associated with primary hyperparathyroidism, is reported. (author)

  1. Benchmarking Brown Dwarf Models With a Non-irradiated Transiting Brown Dwarf in Praesepe

    Science.gov (United States)

    Beatty, Thomas; Marley, Mark; Line, Michael; Gizis, John

    2018-05-01

    We wish to use 9.4 hours of Spitzer time to observe two eclipses, one each at 3.6um and 4.5um, of the transiting brown dwarf AD 3116b. AD 3116b is a 54.2+/-4.3 MJ, 1.08+/-0.07 RJ object on a 1.98 day orbit about a 3200K M-dwarf. Uniquely, AD 3116 and its host star are both members of Praesepe, a 690+/-60 Myr old open cluster. AD 3116b is thus one of two transiting brown dwarfs for which we have a robust isochronal age that is not dependent upon brown dwarf evolutionary models, and the youngest brown dwarf for which this is the case. Importantly, the flux AD 3116b receives from its host star is only 0.7% of its predicted internal luminosity (Saumon & Marley 2008). This makes AD 3116b the first known transiting brown dwarf that simultaneously has a well-defined age, and that receives a negligible amount of external irradiation, and a unique laboratory to test radius and luminosity predictions from brown dwarf evolutionary models. Our goal is to measure the emission from the brown dwarf. AD 3116b should have large, 25 mmag, eclipse depths in the Spitzer bandpasses, and we expect to measure them with a precision of +/-0.50 mmag at 3.6um and +/-0.54 mmag at 4.5um. This will allow us to make measure AD 3116b?s internal effective temperature to +/-40K. We will also use the upcoming Gaia DR2 parallaxes to measure AD 3116b's absolute IRAC magnitudes and color, and hence determine the cloud properties of the atmosphere. As the only known brown dwarf with an independently measured mass, radius, and age, Spitzer measurements of AD 3116b's luminosity and clouds will provide a critical benchmark for brown dwarf observation and theory.

  2. Tidal variations in the Sundarbans estuarine system, India

    Digital Repository Service at National Institute of Oceanography (India)

    Chatterjee, M.; Shankar, D.; Sen, G.K.; Sanyal, P.; Sundar, D.; Michael, G.S.; Chatterjee, A.; Amol, P.; Mukherjee, D.; Suprit, K.; Mukherjee, A.; Vijith, V.; Chatterjee, S.; Basu, A.; Das, M.; Chakraborti, S.; Kalla, A.; Misra, S.K.; Mukhopadhyay, S.; Mandal, G.; Sarkar, K.

    Situated in the eastern coastal state of West Bengal, the Sundarbans Estuarine System (SES) is India’s largest monsoonal, macro-tidal delta-front estuarine system. It comprises the southernmost part of the Indian portion of the Ganga...

  3. Carbohydrate secretion by phototrophic communities in tidal sediments

    NARCIS (Netherlands)

    de Winder, B.; Staats, N.; Stal, L.J.; Paterson, D.M.

    1999-01-01

    Two different benthic phototrophic communities on tidal flats were investigated for their carbohydrate content and distribution. Carbohydrates were analysed as two operationally defined fractions, related to the difficulty of extraction from the sediment matrix. Water-soluble (colloidal) and EDTA-

  4. Anticorrosion and halobios control for tidal power generating units

    International Nuclear Information System (INIS)

    Shen, J C; Ding, L X

    2012-01-01

    The anticorrosion and halobios control is the key techniquesrelated to the safety and durability of tidal power generating units. The technique of material application, antifouling coating and cathodic protection are often adopted. The technical research, application, updating and development are carried on Jiangxia Tidal Power Station, which is based on the old Unit 1-Unit 5 operated for nearly 30 years, and the new Unit 6 operated in 2007. It is found that stainless steeland the antifouling coating used in Unit 1- Unit 5 are very effective, but cathodic protection is often likely to fail because of the limitation of structure and installation. Analyses and studies for anticorrosion and halobios control techniques of tidal power generating units according to theory, experience and actual effects have been done, which can be for reference to the tidal power station designers and builders.

  5. N-Body Simulations of Tidal Encounters between Stellar Systems

    Indian Academy of Sciences (India)

    tribpo

    Saleh Mohammed Alladin† International Centre for Theoretical Physics, ... concentrate on how the tidal field of the primary changes the mass distribution, energy and angular momentum ..... International School for Advanced Studies, Trieste.

  6. Sears Point Tidal Marsh Restoration Project: Phase I

    Science.gov (United States)

    Information about the SFBWQP Sears Point Tidal Marsh Restoration Project: Phase I project, part of an EPA competitive grant program to improve SF Bay water quality focused on restoring impaired waters and enhancing aquatic resources.

  7. Measuring and modeling exposure from environmental radiation on tidal flats

    International Nuclear Information System (INIS)

    Gould, T.J.; Hess, C.T.

    2005-01-01

    To examine the shielding effects of the tide cycle, a high pressure ion chamber was used to measure the exposure rate from environmental radiation on tidal flats. A theoretical model is derived to predict the behavior of exposure rate as a function of time for a detector placed one meter above ground on a tidal flat. The numerical integration involved in this derivation results in an empirical formula which implies exposure rate ∝tan-1(sint). We propose that calculating the total exposure incurred on a tidal flat requires measurements of only the slope of the tidal flat and the exposure rate when no shielding occurs. Experimental results are consistent with the model

  8. The structure of turbulence in a rapid tidal flow.

    Science.gov (United States)

    Milne, I A; Sharma, R N; Flay, R G J

    2017-08-01

    The structure of turbulence in a rapid tidal flow is characterized through new observations of fundamental statistical properties at a site in the UK which has a simple geometry and sedate surface wave action. The mean flow at the Sound of Islay exceeded 2.5 m s -1 and the turbulent boundary layer occupied the majority of the water column, with an approximately logarithmic mean velocity profile identifiable close to the seabed. The anisotropic ratios, spectral scales and higher-order statistics of the turbulence generally agree well with values reported for two-dimensional open channels in the laboratory and other tidal channels, therefore providing further support for the application of universal models. The results of the study can assist in developing numerical models of turbulence in rapid tidal flows such as those proposed for tidal energy generation.

  9. On tidal phenomena in a strong gravitational field

    International Nuclear Information System (INIS)

    Mashoon, B.

    1975-01-01

    A simple framework based on the concept of quadrupole tidal potential is presented for the calculation of tidal deformation of an extended test body in a gravitational field. This method is used to study the behavior of an initially faraway nonrotating spherical body that moves close to a Schwarzschild or an extreme Kerr black hole. In general, an extended body moving in an external gravitational field emits gravitational radiation due to its center of mass motion, internal tidal deformation, and the coupling between the internal and center of mass motions. Estimates are given of the amount of tidal radiation emitted by the body in the gravitational fields considered. The results reported in this paper are expected to be of importance in the dynamical evolution of a dense stellar system with a massive black hole in its center

  10. On tidal radius determination for a globular cluster

    International Nuclear Information System (INIS)

    Ninkovic, S.

    1985-01-01

    A tidal radius determination for a globular cluster based on its density minimum, which is caused by the galactic tidal forces and derivable from a model of the Galaxy, is proposed. Results obtained on the basis of the Schmidt model for two clusters are in a satisfactory agreement with those obtained earlier by means of other methods. A mass determination for the clusters through the tidal radius, when the latter one is identified with the cluster perigalactic distance, yields unusually large mass values. Probably, the tidal radius should be identified with the instantaneous galactocentric distance. Use of models more recent than the Schmidt one indicates that a globular cluster may contain a significant portion of an invisible interstellar matter. (author)

  11. Sears Point Tidal Marsh Restoration Project: Phase II

    Science.gov (United States)

    Information about the SFBWQP Sears Point Tidal Marsh Restoration Project: Phase II, part of an EPA competitive grant program to improve SF Bay water quality focused on restoring impaired waters and enhancing aquatic resources.

  12. Observation of Tidal Effects on LWIR Radiance Above the Mesopause

    National Research Council Canada - National Science Library

    Wintersteiner, Peter

    2007-01-01

    ..., and season The local-time dependence, in particular, suggests a role for atmospheric tides using a tidal model, Global Scale Wave Model, and our non-GTE ARC rode, we modeled the 15 Om radiance...

  13. Emerson Parcel of Dutch Slough Tidal Marsh Restoration Project

    Science.gov (United States)

    Information about the SFBWQP Emerson Parcel of Dutch Slough Tidal Marsh Restoration Project, part of an EPA competitive grant program to improve SF Bay water quality focused on restoring impaired waters and enhancing aquatic resources.

  14. South Bay Salt Pond Tidal Wetland Restoration Phase II Planning

    Science.gov (United States)

    Information about the SFBWQP South Bay Salt Pond Tidal Wetland Restoration Phase II Planning project, part of an EPA competitive grant program to improve SF Bay water quality focused on restoring impaired waters and enhancing aquatic re

  15. Inundation Mapping Tidal Surface - Mean Higher High Water

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data are a derived product of the NOAA VDatum tool and they extend the tool's Mean Higher High Water (MHHW) tidal datum conversion inland beyond its original...

  16. Tidal variations in the Sundarbans Estuarine System, India

    Indian Academy of Sciences (India)

    gle channel; estuaries of this type are by far the most numerous .... the observation stations and describe the methods used. ...... The Cen- tral Inland Fisheries Research Institute, in their .... Qualitative information regarding tidal levels and the ...

  17. Turbine Control of a Tidal and River Power Generator: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Muljadi, Eduard; Gevorgian, Vahan; Wright, Alan; Donegan, James; Marnagh, Cian; McEntee, Jarlath

    2016-08-01

    As renewable generation has become less expensive during recent decades, and it becomes more accepted by the global population, the focus on renewable generation has expanded to include new types with promising future applications, such as river and tidal generation. The input variations to these types of resources are slower but also steadier than wind or solar generation. The level of water turbulent flow may vary from one place to another, however, the control algorithm can be adjusted to local environment. This paper describes the hydrokinetic aspects of river and tidal generation based on a river and tidal generator. Although the information given in this paper is not that of an exact generator deployed on site, the data used is representative of a typical river or tidal generator. In this paper, the hydrokinetic and associated electrical controller of the system were not included; however, the focus of this paper is on the hydrodynamic control.

  18. Fuzzy Control of Tidal volume, Respiration number and Pressure value

    OpenAIRE

    Hasan Guler; Fikret Ata

    2010-01-01

    In this study, control of tidal volume, respiration number and pressure value which are arrived to patient at mechanical ventilator device which is used in intensive care units were performed with fuzzy logic controller. The aim of this system is to reduce workload of aneshesiologist. By calculating tidal volume, respiration number and pressure value, the error Pe(k) between reference pressure value (Pref) and pressure of gas given ill person (Phasta) and error change rate ;#948;Pe(k) were co...

  19. Ultra-protective tidal volume: how low should we go?

    OpenAIRE

    Costa, Eduardo LV; Amato, Marcelo BP

    2013-01-01

    Applying tidal volumes of less than 6 mL/kg might improve lung protection in patients with acute respiratory distress syndrome. In a recent article, Retamal and colleagues showed that such a reduction is feasible with conventional mechanical ventilation and leads to less tidal recruitment and overdistension without causing carbon dioxide retention or auto-positive end-expiratory pressure. However, whether the compensatory increase in the respiratory rate blunts the lung protection remains une...

  20. Heartbeat stars and the ringing of tidal pulsations

    OpenAIRE

    García, RA; Hambleton, K; Kurtz, DW; Prsa, A; Fuller, J; Thompson (SU), S; Ballot, J

    2015-01-01

    With the advent of high precision photometry from satellites such as Kepler and CoRoT, a whole new layer of interesting and astounding astronomical objects has been revealed: heartbeat stars are an example of such objects. Heartbeat stars are eccen- tric ellipsoidal variables that undergo strong tidal interactions when the stars are almost in contact at the time of closest approach. These interactions deform of the stars and cause a notable light curve variation in the form of a tidal pulse. ...

  1. Bedload transport in an inlet channel during a tidal cycle

    DEFF Research Database (Denmark)

    Ernstsen, V. B.; Becker, M.; Winter, C.

    2007-01-01

      Based on high-resolution swath bathymetry measurements at centimetre-scale precision conducted during a tidal cycle in a dune field in the Grådyb tidal inlet channel in the DanishWadden Sea, a simple tool to calculate bedload transport is presented. Bedload transport was related to simultaneous...... variations in grain-size composition of the mobilised sediment should be taken into account by sediment transport formulae....

  2. Tidal Current Energy Resource Assessment Around Buton Island, Southeast Sulawesi, Indonesia

    OpenAIRE

    Ribal, Agustinus; Amir, Amir Kamal; Toaha, Syamsuddin; Kusuma, Jeffry; Khaeruddin

    2017-01-01

    International Journal bereputasi An early stage of assessing tidal current energy resources is carried out in this present work. Tidal current power is estimated around Buton Island, Southeast Sulawesi province, Indonesia. Two-dimensional, depth-integrated of Advanced Circulation (ADCIRC) model has been used to simulate tidal elevation and barotropic tidal current around the island. Green???s function approach has been used to improve eight tidal constituents on the open boundary condition...

  3. From Globular Clusters to Tidal Dwarfs: Structure Formation in the Tidal Tails of Merging Pairs

    Science.gov (United States)

    Knierman, K. A.; Gallagher, S. C.; Charlton, J. C.; Hunsberger, S. D.; Whitmore, B. C.; Kundu, A.; Hibbard, J. E.; Zaritsky, D. F.

    2001-05-01

    Using V and I images obtained with the Wide Field Planetary Camera 2 (WFPC2) of the Hubble Space Telescope, we investigate compact stellar structures within tidal tails. Six regions of tidal debris in the four classic ``Toomre Sequence'' mergers: NGC 4038/9 (``Antennae''), NGC 3256, NGC 3921, and NGC 7252 (``Atoms for Peace'') have been studied in order to explore how the star formation depends upon the local and global physical conditions. These mergers sample a range of stages in the evolutionary sequence, and include HI--rich and HI--poor environments. The six tails are found to contain a variety of stellar structures, with sizes ranging from those of globular clusters up to those of dwarf galaxies. From V and I WFPC2 images, we measure the luminosities and colors of the star clusters. NGC 3256 is found to have a large population of young clusters lying along both tails, similar to those found in the inner region of the merger. In contrast, NGC 4038/9 has no clusters in the observed region of the tail, only less luminous point sources likely to be individual stars. NGC 3921 and NGC 7252 have small populations of clusters that are concentrated in certain regions of the tail, and particularly in the prominent tidal dwarfs in the eastern and western tails of NGC 7252. The two cluster--rich tails of NGC 3256 are not distinguished from the others by their ages or by their total HI masses. We acknowledge support from NASA through STScI, and from NSF for an REU supplement for Karen Knierman.

  4. Habitable Planets Around White and Brown Dwarfs: The Perils of a Cooling Primary

    Science.gov (United States)

    Heller, René

    2013-01-01

    Abstract White and brown dwarfs are astrophysical objects that are bright enough to support an insolation habitable zone (IHZ). Unlike hydrogen-burning stars, they cool and become less luminous with time; hence their IHZ moves in with time. The inner edge of the IHZ is defined as the orbital radius at which a planet may enter a moist or runaway greenhouse, phenomena that can remove a planet's surface water forever. Thus, as the IHZ moves in, planets that enter it may no longer have any water and are still uninhabitable. Additionally, the close proximity of the IHZ to the primary leads to concern that tidal heating may also be strong enough to trigger a runaway greenhouse, even for orbital eccentricities as small as 10−6. Water loss occurs due to photolyzation by UV photons in the planetary stratosphere, followed by hydrogen escape. Young white dwarfs emit a large amount of these photons, as their surface temperatures are over 104 K. The situation is less clear for brown dwarfs, as observational data do not constrain their early activity and UV emission very well. Nonetheless, both types of planets are at risk of never achieving habitable conditions, but planets orbiting white dwarfs may be less likely to sustain life than those orbiting brown dwarfs. We consider the future habitability of the planet candidates KOI 55.01 and 55.02 in these terms and find they are unlikely to become habitable. Key Words: Extrasolar terrestrial planets—Habitability—Habitable zone—Tides—Exoplanets. Astrobiology 13, 279–291. PMID:23537137

  5. On the sedimentation problems in water abstraction channels at power plant sites at tidal estuaries

    International Nuclear Information System (INIS)

    Jensen, J.; Arns, A.; Frank, T.; Meiswinkel, R.; Richei, A.

    2010-01-01

    The required cooling water supply of a nuclear power plant the required flow deepness in the water abstraction channels has to be provided. Since the abstraction channels are usually in main stream orientation of the river periodic sedimentation occur, that have to be removed by dredging techniques. Especially in tidal estuaries the complex flow situation induces transport mechanisms that have to be studied in order to develop cost saving and effective measures and procedures to reduce the sedimentation and pollutants deposition. The authors recommend experimental determinations of the sold material transport and numerical hydrodynamic transport modeling to identify the transport pathways.

  6. Tidal Turbines’ Layout in a Stream with Asymmetry and Misalignment

    Directory of Open Access Journals (Sweden)

    Nicolas Guillou

    2017-11-01

    Full Text Available A refined assessment of tidal currents variability is a prerequisite for successful turbine deployment in the marine environment. However, the numerical evaluation of the tidal kinetic energy resource relies, most of the time, on integrated parameters, such as the averaged or maximum stream powers. Predictions from a high resolution three-dimensional model are exploited here to characterize the asymmetry and misalignment between the flood and ebb tidal currents in the “Raz de Sein”, a strait off western Brittany (France with strong potential for array development. A series of parameters is considered to assess resource variability and refine the cartography of local potential tidal stream energy sites. The strait is characterized by strong tidal flow divergence with currents’ asymmetry liable to vary output power by 60% over a tidal cycle. Pronounced misalignments over 20 ∘ are furthermore identified in a great part of energetic locations, and this may account for a deficit of the monthly averaged extractable energy by more than 12%. As sea space is limited for turbines, it is finally suggested to aggregate flood and ebb-dominant stream powers on both parts of the strait to output energy with reduced asymmetry.

  7. A new high resolution tidal model in the arctic ocean

    DEFF Research Database (Denmark)

    Cancet, M.; Andersen, Ole Baltazar; Lyard, F.

    The Arctic Ocean is a challenging region for tidal modeling, because of its complex and not well-documented bathymetry, together combined with the intermittent presence of sea ice and the fact that the in situ tidal observations are rather scarce at such high latitudes. As a consequence, the accu......The Arctic Ocean is a challenging region for tidal modeling, because of its complex and not well-documented bathymetry, together combined with the intermittent presence of sea ice and the fact that the in situ tidal observations are rather scarce at such high latitudes. As a consequence......, the accuracy of the global tidal models decreases by several centimeters in the Polar Regions. In particular, it has a large impact on the quality of the satellite altimeter sea surface heights in these regions (ERS1/2, Envisat, CryoSat-2, SARAL/AltiKa and the future Sentinel-3 mission). Better knowledge......-growing maritime and industrial activities in this region. NOVELTIS and DTU Space have developed a regional, high-resolution tidal atlas in the Arctic Ocean, in the framework of the CryoSat Plus for Ocean (CP4O) ESA project. In particular, this atlas benefits from the assimilation of the most complete satellite...

  8. Will Tidal Wetland Restoration Enhance Populations of Native Fishes?

    Directory of Open Access Journals (Sweden)

    Larry R. Brown

    2003-10-01

    Full Text Available Restoration of tidal wetlands might enhance populations of native fishes in the San Francisco Estuary of California. The purpose of this paper is to: (1 review the currently available information regarding the importance of tidal wetlands to native fishes in the San Francisco Estuary, (2 construct conceptual models on the basis of available information, (3 identify key areas of scientific uncertainty, and (4 identify methods to improve conceptual models and reduce uncertainty. There are few quantitative data to suggest that restoration of tidal wetlands will substantially increase populations of native fishes. On a qualitative basis, there is some support for the idea that tidal wetland restoration will increase populations of some native fishes; however, the species deriving the most benefit from restoration might not be of great management concern at present. Invasion of the San Francisco Estuary by alien plants and animals appears to be a major factor in obscuring the expected link between tidal wetlands and native fishes. Large-scale adaptive management experiments (>100 hectares appear to be the best available option for determining whether tidal wetlands will provide significant benefit to native fishes. Even if these experiments are unsuccessful at increasing native fish populations, the restored wetlands should benefit native birds, plants, and other organisms.

  9. The prediction of the hydrodynamic performance of tidal current turbines

    International Nuclear Information System (INIS)

    Xiao, B Y; Zhou, L J; Xiao, Y X; Wang, Z W

    2013-01-01

    Nowadays tidal current energy is considered to be one of the most promising alternative green energy resources and tidal current turbines are used for power generation. Prediction of the open water performance around tidal turbines is important for the reason that it can give some advice on installation and array of tidal current turbines. This paper presents numerical computations of tidal current turbines by using a numerical model which is constructed to simulate an isolated turbine. This paper aims at studying the installation of marine current turbine of which the hydro-environmental impacts influence by means of numerical simulation. Such impacts include free-stream velocity magnitude, seabed and inflow direction of velocity. The results of the open water performance prediction show that the power output and efficiency of marine current turbine varies from different marine environments. The velocity distribution should be clearly and the suitable unit installation depth and direction be clearly chosen, which can ensure the most effective strategy for energy capture before installing the marine current turbine. The findings of this paper are expected to be beneficial in developing tidal current turbines and array in the future

  10. Assessment of Kinetic Tidal Energy Resources Using SELFE

    Directory of Open Access Journals (Sweden)

    Manasa Ranjan Behera

    2014-09-01

    Full Text Available An investigation is carried out to study the theoretical tidal stream energy resource in the Singapore Strait to support the search for renewable energy in the effort to reduce the carbon footprints in the Southeast Asia. The tidal hydrodynamics in the Singapore Strait has been simulated using a Semi-implicit Eulerian-Lagrangian Finite-Element (SELFE model solving the 3D shallow water equations with Boussinesq approximations. Potential sites, with high tidal current (2.5 m/s and suitable for Tidal Energy Converter (TEC array installation to generate sustainable energy, have been identified. Further, various operational factors for installation of Tidal Energy Converters are considered before computing the theoretical power output for a typical TEC array. An approximate estimation of the possible theoretical power extraction from a TEC array shows an energy potential of up to 4.36% of the total energy demand of Singapore in 2011. Thus, the study suggests a detailed investigation of potential sites to quantify the total tidal stream energy potential in the Singapore Strait.

  11. The environmental interactions of tidal and wave energy generation devices

    International Nuclear Information System (INIS)

    Frid, Chris; Andonegi, Eider; Depestele, Jochen; Judd, Adrian; Rihan, Dominic; Rogers, Stuart I.; Kenchington, Ellen

    2012-01-01

    Global energy demand continues to grow and tidal and wave energy generation devices can provide a significant source of renewable energy. Technological developments in offshore engineering and the rising cost of traditional energy means that offshore energy resources will be economic in the next few years. While there is now a growing body of data on the ecological impacts of offshore wind farms, the scientific basis on which to make informed decisions about the environmental effects of other offshore energy developments is lacking. Tidal barrages have the potential to cause significant ecological impacts particularly on bird feeding areas when they are constructed at coastal estuaries or bays. Offshore tidal stream energy and wave energy collectors offer the scope for developments at varying scales. They also have the potential to alter habitats. A diversity of designs exist, including floating, mid-water column and seabed mounted devices, with a variety of moving-part configurations resulting in a unique complex of potential environmental effects for each device type, which are discussed to the extent possible. - Highlights: ► We review the environmental impacts of tidal barrages and fences, tidal stream farms and wave energy capture devices. ► Impacts on habitats, species and the water column, and effects of noise and electromagnetic fields are considered. ► Tidal barrages can cause significant impacts on bird feeding areas when constructed at coastal estuaries or bays. ► Wave energy collectors can alter water column and sea bed habitats locally and over large distances.

  12. Tidal energy, a renewable energy within hand reach

    International Nuclear Information System (INIS)

    Danielo, O.

    2011-01-01

    Tide energy and oceanic current energy represent a strong potentiality for a few countries in the world including France. In the domain of tidal energy there are 2 strategies. The first one is based on the search for the lowest power production cost in order to contribute efficiently to the country's energy mix. Generally this strategy leads to the construction of tidal dams. The second strategy is based on the search for the lowest environmental impact. This strategy is economically competitive only in places where electrical power is expensive like isolated islands. This strategy is illustrated by the tidal power station of the Alderney island. In fact the amount of energy delivered by a tidal power station depends on the rise of the tide and on the surface of the dam. It appears that tidal dams require less surface that hydroelectric power plants. The energy of oceanic currents like Gulf Stream or the thermal energy of oceans or wave power are very little exploited now but represent a potentiality higher by several orders of magnitude than tidal energy. (A.C.)

  13. Tidal interaction of black holes and Newtonian viscous bodies

    International Nuclear Information System (INIS)

    Poisson, Eric

    2009-01-01

    The tidal interaction of a (rotating or nonrotating) black hole with nearby bodies produces changes in its mass, angular momentum, and surface area. Similarly, tidal forces acting on a Newtonian, viscous body do work on the body, change its angular momentum, and part of the transferred gravitational energy is dissipated into heat. The equations that describe the rate of change of the black-hole mass, angular momentum, and surface area as a result of the tidal interaction are compared with the equations that describe how the tidal forces do work, torque, and produce heat in the Newtonian body. The equations are strikingly similar, and unexpectedly, the correspondence between the Newtonian-body and black-hole results is revealed to hold in near-quantitative detail. The correspondence involves the combination k 2 τ of 'Love quantities' that incorporate the details of the body's internal structure; k 2 is the tidal Love number, and τ is the viscosity-produced delay between the action of the tidal forces and the body's reaction. The combination k 2 τ is of order GM/c 3 for a black hole of mass M; it does not vanish, in spite of the fact that k 2 is known to vanish individually for a nonrotating black hole.

  14. TWO NEW TIDALLY DISTORTED WHITE DWARFS

    Energy Technology Data Exchange (ETDEWEB)

    Hermes, J. J.; Montgomery, M. H.; Winget, D. E. [Department of Astronomy, University of Texas at Austin, Austin, TX 78712 (United States); Kilic, Mukremin [Homer L. Dodge Department of Physics and Astronomy, University of Oklahoma, 440 W. Brooks St., Norman, OK 73019 (United States); Brown, Warren R., E-mail: jjhermes@astro.as.utexas.edu [Smithsonian Astrophysical Observatory, 60 Garden St, Cambridge, MA 02138 (United States)

    2012-04-10

    We identify two new tidally distorted white dwarfs (WDs), SDSS J174140.49+652638.7 and J211921.96-001825.8 (hereafter J1741 and J2119). Both stars are extremely low mass (ELM, {<=} 0.2 M{sub Sun }) WDs in short-period, detached binary systems. High-speed photometric observations obtained at the McDonald Observatory reveal ellipsoidal variations and Doppler beaming in both systems; J1741, with a minimum companion mass of 1.1 M{sub Sun }, has one of the strongest Doppler beaming signals ever observed in a binary system (0.59% {+-} 0.06% amplitude). We use the observed ellipsoidal variations to constrain the radius of each WD. For J1741, the star's radius must exceed 0.074 R{sub Sun }. For J2119, the radius exceeds 0.10 R{sub Sun }. These indirect radius measurements are comparable to the radius measurements for the bloated WD companions to A-stars found by the Kepler spacecraft, and they constitute some of the largest radii inferred for any WD. Surprisingly, J1741 also appears to show a 0.23% {+-} 0.06% reflection effect, and we discuss possible sources for this excess heating. Both J1741 and J2119 are strong gravitational wave sources, and the time-of-minimum of the ellipsoidal variations can be used to detect the orbital period decay. This may be possible on a timescale of a decade or less.

  15. Formation and evolution of tidal binary systems

    International Nuclear Information System (INIS)

    Mcmillan, S.L.W.; Mcdermott, P.N.; Taam, R.E.

    1987-01-01

    Cross sections for the tidal capture binary formation process are calculated for a variety of stellar models. The formalism used in the determination of the energy dissipated by a close encounter between two unbound stars and the associated capture cross sections are reviewed. The case of an n = 3/2 polytropic structure is calculated with the formalism, and the behavior of realistic stellar models is considered, including Population II main-sequence stars with masses of 0.4, 0.8, and 1.5 solar. The calculation is repeated for a slightly evolved 0.8 solar mass star just as it begins to leave the main sequence, and the behavior of more evolved stars is discussed. A quasi-adiabatic analysis is used to estimate the time scale on which the pulsation energy is actually dissipated internally or radiated away. This analysis also indicates where in the star most of the dissipation takes place, allowing the stellar response to be estimated by including the heating in the equations of stellar structure. 41 references

  16. Tidal Love Numbers of Neutron Stars

    International Nuclear Information System (INIS)

    Hinderer, Tanja

    2008-01-01

    For a variety of fully relativistic polytropic neutron star models we calculate the star's tidal Love number k 2 . Most realistic equations of state for neutron stars can be approximated as a polytrope with an effective index n ∼ 0.5-1.0. The equilibrium stellar model is obtained by numerical integration of the Tolman-Oppenheimer-Volkhov equations. We calculate the linear l = 2 static perturbations to the Schwarzschild spacetime following the method of Thorne and Campolattaro. Combining the perturbed Einstein equations into a single second-order differential equation for the perturbation to the metric coefficient g tt and matching the exterior solution to the asymptotic expansion of the metric in the star's local asymptotic rest frame gives the Love number. Our results agree well with the Newtonian results in the weak field limit. The fully relativistic values differ from the Newtonian values by up to ∼24%. The Love number is potentially measurable in gravitational wave signals from inspiralling binary neutron stars.

  17. Simultaneous perturbation stochastic approximation for tidal models

    KAUST Repository

    Altaf, M.U.

    2011-05-12

    The Dutch continental shelf model (DCSM) is a shallow sea model of entire continental shelf which is used operationally in the Netherlands to forecast the storm surges in the North Sea. The forecasts are necessary to support the decision of the timely closure of the moveable storm surge barriers to protect the land. In this study, an automated model calibration method, simultaneous perturbation stochastic approximation (SPSA) is implemented for tidal calibration of the DCSM. The method uses objective function evaluations to obtain the gradient approximations. The gradient approximation for the central difference method uses only two objective function evaluation independent of the number of parameters being optimized. The calibration parameter in this study is the model bathymetry. A number of calibration experiments is performed. The effectiveness of the algorithm is evaluated in terms of the accuracy of the final results as well as the computational costs required to produce these results. In doing so, comparison is made with a traditional steepest descent method and also with a newly developed proper orthogonal decompositionbased calibration method. The main findings are: (1) The SPSA method gives comparable results to steepest descent method with little computational cost. (2) The SPSA method with little computational cost can be used to estimate large number of parameters.

  18. Stingray tidal stream energy device - phase 3

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2005-07-01

    The 150 kW Stingray demonstrator was designed, built and installed by The Engineering Business (EB) in 2002, becoming the world's first full-scale tidal stream generator. The concept and technology are described in the reports from Phases 1 and 2 of the project. This report provides an overview of Phase 3 - the re-installation of Stingray in Yell Sound in the Shetland Isles between July and September 2003 for further testing at slack water and on the flood tide to confirm basic machine characteristics, develop the control strategy and to demonstrate performance and power collection through periods of continuous operation. The overall aim was to demonstrate that electricity could be generated at a potentially commercially viable unit energy cost; cost modelling indicated a future unit energy cost of 6.7 pence/kWh when 100 MW capacity had been installed. The report describes: project objectives, targets and activities; design and production; marine operations including installation and demobilisation; environmental monitoring and impact, including pre-installation and post-decommissioning surveys; stakeholder involvement; test results on machine characteristics, sensor performance, power cycle analysis, power collection, transmission performance and efficiency, current data analysis; validation of the mathematical model; the background to the economic model; cost modelling; and compliance with targets set by the Department of Trade and Industry (DTI).

  19. Simultaneous perturbation stochastic approximation for tidal models

    KAUST Repository

    Altaf, M.U.; Heemink, A.W.; Verlaan, M.; Hoteit, Ibrahim

    2011-01-01

    The Dutch continental shelf model (DCSM) is a shallow sea model of entire continental shelf which is used operationally in the Netherlands to forecast the storm surges in the North Sea. The forecasts are necessary to support the decision of the timely closure of the moveable storm surge barriers to protect the land. In this study, an automated model calibration method, simultaneous perturbation stochastic approximation (SPSA) is implemented for tidal calibration of the DCSM. The method uses objective function evaluations to obtain the gradient approximations. The gradient approximation for the central difference method uses only two objective function evaluation independent of the number of parameters being optimized. The calibration parameter in this study is the model bathymetry. A number of calibration experiments is performed. The effectiveness of the algorithm is evaluated in terms of the accuracy of the final results as well as the computational costs required to produce these results. In doing so, comparison is made with a traditional steepest descent method and also with a newly developed proper orthogonal decompositionbased calibration method. The main findings are: (1) The SPSA method gives comparable results to steepest descent method with little computational cost. (2) The SPSA method with little computational cost can be used to estimate large number of parameters.

  20. Stingray tidal stream energy device - phase 3

    International Nuclear Information System (INIS)

    2005-01-01

    The 150 kW Stingray demonstrator was designed, built and installed by The Engineering Business (EB) in 2002, becoming the world's first full-scale tidal stream generator. The concept and technology are described in the reports from Phases 1 and 2 of the project. This report provides an overview of Phase 3 - the re-installation of Stingray in Yell Sound in the Shetland Isles between July and September 2003 for further testing at slack water and on the flood tide to confirm basic machine characteristics, develop the control strategy and to demonstrate performance and power collection through periods of continuous operation. The overall aim was to demonstrate that electricity could be generated at a potentially commercially viable unit energy cost; cost modelling indicated a future unit energy cost of 6.7 pence/kWh when 100 MW capacity had been installed. The report describes: project objectives, targets and activities; design and production; marine operations including installation and demobilisation; environmental monitoring and impact, including pre-installation and post-decommissioning surveys; stakeholder involvement; test results on machine characteristics, sensor performance, power cycle analysis, power collection, transmission performance and efficiency, current data analysis; validation of the mathematical model; the background to the economic model; cost modelling; and compliance with targets set by the Department of Trade and Industry (DTI)

  1. Stage-discharge relationship in tidal channels

    Science.gov (United States)

    Kearney, W. S.; Mariotti, G.; Deegan, L.; Fagherazzi, S.

    2016-12-01

    Long-term records of the flow of water through tidal channels are essential to constrain the budgets of sediments and biogeochemical compounds in salt marshes. Statistical models which relate discharge to water level allow the estimation of such records from more easily obtained records of water stage in the channel. While there is clearly structure in the stage-discharge relationship, nonlinearity and nonstationarity of the relationship complicates the construction of statistical stage-discharge models with adequate performance for discharge estimation and uncertainty quantification. Here we compare four different types of stage-discharge models, each of which is designed to capture different characteristics of the stage-discharge relationship. We estimate and validate each of these models on a two-month long time series of stage and discharge obtained with an Acoustic Doppler Current Profiler in a salt marsh channel. We find that the best performance is obtained by models which account for the nonlinear and time-varying nature of the stage-discharge relationship. Good performance can also be obtained from a simplified version of these models which approximates the fully nonlinear and time-varying models with a piecewise linear formulation.

  2. A Unified Model for Tidal Disruption Events

    Science.gov (United States)

    Dai, Lixin; McKinney, Jonathan C.; Roth, Nathaniel; Ramirez-Ruiz, Enrico; Miller, M. Coleman

    2018-06-01

    In the past few years wide-field optical and UV transient surveys and X-ray telescopes have allowed us to identify a few dozen candidate tidal disruption events (TDEs). While in theory the physical processes in TDEs are ubiquitous, a few distinct classes of TDEs have been observed. Some TDEs radiate mainly in NUV/optical, while others produce prominent X-rays. Moreover, relativistic jets have been observed in only a handful of TDEs. This diversity might be related to the details of the super-Eddington accretion and emission physics relevant to TDE disks. In this Letter, we utilize novel three-dimensional general relativistic radiation magnetohydrodynamics simulations to study the super-Eddington compact disk phase expected in TDEs. Consistent with previous studies, geometrically thick disks, wide-angle optically thick fast outflows, and relativistic jets are produced. The outflow density and velocity depend sensitively on the inclination angle, and hence so does the reprocessing of emission produced from the inner disk. We then use Monte Carlo radiative transfer to calculate the reprocessed spectra and find that that the observed ratio of optical to X-ray fluxes increases with increasing inclination angle. This naturally leads to a unified model for different classes of TDEs in which the spectral properties of the TDE depend mainly on the viewing angle of the observer with respect to the orientation of the disk.

  3. On the ecogeomorphological feedbacks that control tidal channel network evolution in a sandy mangrove setting

    Science.gov (United States)

    van Maanen, B.; Coco, G.; Bryan, K. R.

    2015-01-01

    An ecomorphodynamic model was developed to study how Avicennia marina mangroves influence channel network evolution in sandy tidal embayments. The model accounts for the effects of mangrove trees on tidal flow patterns and sediment dynamics. Mangrove growth is in turn controlled by hydrodynamic conditions. The presence of mangroves was found to enhance the initiation and branching of tidal channels, partly because the extra flow resistance in mangrove forests favours flow concentration, and thus sediment erosion in between vegetated areas. The enhanced branching of channels is also the result of a vegetation-induced increase in erosion threshold. On the other hand, this reduction in bed erodibility, together with the soil expansion driven by organic matter production, reduces the landward expansion of channels. The ongoing accretion in mangrove forests ultimately drives a reduction in tidal prism and an overall retreat of the channel network. During sea-level rise, mangroves can potentially enhance the ability of the soil surface to maintain an elevation within the upper portion of the intertidal zone, while hindering both the branching and headward erosion of the landward expanding channels. The modelling results presented here indicate the critical control exerted by ecogeomorphological interactions in driving landscape evolution. PMID:26339195

  4. Tidal variations of flow convergence, shear, and stratification at the Rio de la Plata estuary turbidity front

    Science.gov (United States)

    FramiñAn, Mariana B.; Valle-Levinson, Arnoldo; Sepúlveda, HéCtor H.; Brown, Otis B.

    2008-08-01

    Intratidal variability of density and velocity fields is investigated at the turbidity front of the Río de la Plata Estuary, South America. Current velocity and temperature-salinity profiles collected in August 1999 along a repeated transect crossing the front are analyzed. Horizontal and vertical gradients, stability of the front, convergence zones, and transverse flow associated to the frontal boundary are described. Strong horizontal convergence of the across-front velocity and build up of along-front velocity shear were observed at the front. In the proximity of the front, enhanced transverse (or along-front) flow created jet-like structures at the surface and near the bottom flowing in opposite directions. These structures persisted throughout the tidal cycle and were advected upstream (downstream) by the flood (ebb) current through a distance of ˜10 km. During peak flood, the upper layer flow reversed from its predominant downstream direction and upstreamflow occupied the entire water column; outside the peak flood, two-layer estuarine circulation dominated. Changes in density field were observed in response to tidal straining, tidal advection, and wind-induced mixing, but stratification remained throughout the tidal cycle. This work demonstrates the large spatial variability of the velocity field at the turbidity front; it provides evidence of enhanced transverse circulation along the frontal boundary; and reveals the importance of advective and frictional intratidal processes in the dynamics of the central part of the estuary.

  5. Estuary-wide genetic stock distribution and salmon habitat use, tidal-fluvial estuary - Columbia River Estuary Tidal Habitats

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The goal of the tidal-fluvial estuary study is to determine the estuary's contribution to the spatial structure and life history diversity of Columbia River salmon...

  6. Phospholipids of New Zealand Edible Brown Algae.

    Science.gov (United States)

    Vyssotski, Mikhail; Lagutin, Kirill; MacKenzie, Andrew; Mitchell, Kevin; Scott, Dawn

    2017-07-01

    Edible brown algae have attracted interest as a source of beneficial allenic carotenoid fucoxanthin, and glyco- and phospholipids enriched in polyunsaturated fatty acids. Unlike green algae, brown algae contain no or little phosphatidylserine, possessing an unusual aminophospholipid, phosphatidyl-O-[N-(2-hydroxyethyl) glycine], PHEG, instead. When our routinely used technique of 31 P-NMR analysis of phospholipids was applied to the samples of edible New Zealand brown algae, a number of signals corresponding to unidentified phosphorus-containing compounds were observed in total lipids. NI (negative ion) ESI QToF MS spectra confirmed the presence of more familiar phospholipids, and also suggested the presence of PHEG or its isomers. The structure of PHEG was confirmed by comparison with a synthetic standard. An unusual MS fragmentation pattern that was also observed prompted us to synthesise a number of possible candidates, and was found to follow that of phosphatidylhydroxyethyl methylcarbamate, likely an extraction artefact. An unexpected outcome was the finding of ceramidephosphoinositol that has not been reported previously as occurring in brown algae. An uncommon arsenic-containing phospholipid has also been observed and quantified, and its TLC behaviour studied, along with that of the newly synthesised lipids.

  7. Tom Brown appointed Dean of Students

    OpenAIRE

    Williams, Meghan

    2007-01-01

    James Thomas "Tom" Brown, former senior associate dean of the Dean of Students office, has been appointed as the Dean of Students. The Dean of Students office is responsible for the coordination of student advocacy, new student orientation and parent programs, and responding to student emergencies in collaboration with Judicial Affairs, Residence Life, Cook Counseling Center, Schiffert Health Center, and other departments and agencies.

  8. How Glassy States Affect Brown Carbon Production?

    Science.gov (United States)

    Liu, P.; Li, Y.; Wang, Y.; Bateman, A. P.; Zhang, Y.; Gong, Z.; Gilles, M. K.; Martin, S. T.

    2015-12-01

    Secondary organic material (SOM) can become light-absorbing (i.e. brown carbon) via multiphase reactions with nitrogen-containing species such as ammonia and amines. The physical states of SOM, however, potentially slow the diffusion of reactant molecules in organic matrix under conditions that semisolids or solids prevail, thus inhibiting the browning reaction pathways. In this study, the physical states and the in-particle diffusivity were investigated by measuring the evaporation kinetics of both water and organics from aromatic-derived SOMs using a quartz-crystal-microbalance (QCM). The results indicate that the SOMs derived from aromatic precursors toluene and m-xylene became solid (glassy) and the in particle diffusion was significantly impeded for sufficiently low relative humidity ( toluene-derived SOM after ammonia exposure at varied RHs. The results suggest that the production of light-absorbing nitrogen-containing compounds from multiphase reactions with ammonia was kinetically limited in the glassy organic matrix, which otherwise produce brown carbon. The results of this study have significant implications for production and optical properties of brown carbon in urban atmospheres that ultimately influence the climate and tropospheric photochemistry.

  9. Trustworthy-looking face meets brown eyes.

    Directory of Open Access Journals (Sweden)

    Karel Kleisner

    Full Text Available We tested whether eye color influences perception of trustworthiness. Facial photographs of 40 female and 40 male students were rated for perceived trustworthiness. Eye color had a significant effect, the brown-eyed faces being perceived as more trustworthy than the blue-eyed ones. Geometric morphometrics, however, revealed significant correlations between eye color and face shape. Thus, face shape likewise had a significant effect on perceived trustworthiness but only for male faces, the effect for female faces not being significant. To determine whether perception of trustworthiness was being influenced primarily by eye color or by face shape, we recolored the eyes on the same male facial photos and repeated the test procedure. Eye color now had no effect on perceived trustworthiness. We concluded that although the brown-eyed faces were perceived as more trustworthy than the blue-eyed ones, it was not brown eye color per se that caused the stronger perception of trustworthiness but rather the facial features associated with brown eyes.

  10. Brown midrib sorghum deserves a look

    Science.gov (United States)

    Forage sorghum varieties have been developed to allow them to thrive under low moisture and poor soil conditions while producing adequate amounts of forage. In addition, newer varieties, such as the brown midrib (BMR) hybrids, can be alternatives to conventional varieties as they contain less lignin...

  11. PHYSIOLOGICAL ACTIVITY OF THE BROWN ADIPOSE TISSUE.

    Science.gov (United States)

    Studies were performed to clarify the influence of various factors which might be involved in vascular regulation. Topical application of lidocain ...and treatment with reserpine effectively blocked, while denervation of brown fat, syrosingopine and atropine were ineffective to prevent the blood flow

  12. Black-Brown Relations and Stereotypes.

    Science.gov (United States)

    Mindiola, Tatcho Jr.; Niemann, Yolanda Flores; Rodriguez, Nestor

    This book analyzes how African and Hispanic Americans perceive and interact with one another, highlighting black-brown relations in Houston, Texas, one of the largest cities with a majority ethnic population and one in which Hispanic Americans outnumber African Americans. Using results from several sociological studies, the book examines: how each…

  13. Black-Brown Relations: Are Alliances Possible?

    Science.gov (United States)

    Klor de Alva, J. Jorge; West, Cornel

    1997-01-01

    Dialogue between Cornel West and Jorge Klor de Alva explores the question of black-brown alliances, those between African Americans and Hispanic Americans. If minority groups can put aside the difference of skin color and join to combat economic and social racism, they can have far-reaching and meaningful impacts on society. (SLD)

  14. 21 CFR 184.1120 - Brown algae.

    Science.gov (United States)

    2010-04-01

    ... used in food only within the following specific limitations: Category of food Maximum level of use in... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Brown algae. 184.1120 Section 184.1120 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN...

  15. Molecular Selectivity of Brown Carbon Chromophores

    Energy Technology Data Exchange (ETDEWEB)

    Laskin, Julia; Laskin, Alexander; Nizkorodov, Sergey; Roach, Patrick J.; Eckert, Peter A.; Gilles, Mary K.; Wang, Bingbing; Lee, Hyun Ji; Hu, Qichi

    2014-10-21

    Complementary methods of high-resolution mass spectrometry and micro-spectroscopy were utilized for molecular analysis of secondary organic aerosol (SOA) generated from ozonolysis of two structural monoterpene isomers: D-limonene (LSOA) and a-pinene (PSOA). Laboratory simulated aging of LSOA and PSOA, through conversion of carbonyls into imines mediated by NH3 vapors in humid air, resulted in selective browning of the LSOA sample, while the PSOA sample remained white. Comparative analysis of the reaction products in the aged LSOA and PSOA samples provided insights into chemistry relevant to formation of brown carbon chromophores. A significant fraction of carbonyl-imine conversion products with identical molecular formulas were detected in both samples. This reflects the high level of similarity in the molecular composition of these two closely related SOA materials. Several highly conjugated products were detected exclusively in the brown LSOA sample and were identified as potential chromophores responsible for the observed color change. The majority of the unique products in the aged LSOA sample with the highest number of double bonds contain two nitrogen atoms. We conclude that chromophores characteristic of the carbonyl- imine chemistry in LSOA are highly conjugated oligomers of secondary imines (Schiff bases) present at relatively low concentrations. Formation of this type of conjugated compounds in PSOA is hindered by the structural rigidity of the a-pinene oxidation products. Our results suggest that the overall light-absorbing properties of SOA may be determined by trace amounts of strong brown carbon chromophores.

  16. Maxillary brown tumour: unusual presentation of parathyroid ...

    African Journals Online (AJOL)

    This is a report of a maxillary brown tumour caused by primary hyperparathyroidism (HPT) secondary to parathyroid carcinoma. A 62-year-old man presented with a large swelling in the right maxilla, which caused right-sided nasal obstruction, intermittent bleeding and diplopia. A computed tomography scan demonstrated ...

  17. Treatment of peat, brown coal, etc

    Energy Technology Data Exchange (ETDEWEB)

    Francke, F C

    1917-11-02

    Treatment of peat, brown coal, lignite, sapropel, oil shale, wood and the like, characterized by the fact, that the material is dried in a drum having side gas-entrance and gas-exit pipes, and is provided in the known way with ledges under slow turning and then is distilled at a temperature below 550/sup 0/ C.

  18. Fatty acid oxidation is required for active and quiescent brown adipose tissue maintenance and thermogenic programing

    Directory of Open Access Journals (Sweden)

    Elsie Gonzalez-Hurtado

    2018-01-01

    Full Text Available Objective: To determine the role of fatty acid oxidation on the cellular, molecular, and physiologic response of brown adipose tissue to disparate paradigms of chronic thermogenic stimulation. Methods: Mice with an adipose-specific loss of Carnitine Palmitoyltransferase 2 (Cpt2A−/−, that lack mitochondrial long chain fatty acid β-oxidation, were subjected to environmental and pharmacologic interventions known to promote thermogenic programming in adipose tissue. Results: Chronic administration of β3-adrenergic (CL-316243 or thyroid hormone (GC-1 agonists induced a loss of BAT morphology and UCP1 expression in Cpt2A−/− mice. Fatty acid oxidation was also required for the browning of white adipose tissue (WAT and the induction of UCP1 in WAT. In contrast, chronic cold (15 °C stimulation induced UCP1 and thermogenic programming in both control and Cpt2A−/− adipose tissue albeit to a lesser extent in Cpt2A−/− mice. However, thermoneutral housing also induced the loss of UCP1 and BAT morphology in Cpt2A−/− mice. Therefore, adipose fatty acid oxidation is required for both the acute agonist-induced activation of BAT and the maintenance of quiescent BAT. Consistent with this data, Cpt2A−/− BAT exhibited increased macrophage infiltration, inflammation and fibrosis irrespective of BAT activation. Finally, obese Cpt2A−/− mice housed at thermoneutrality exhibited a loss of interscapular BAT and were refractory to β3-adrenergic-induced energy expenditure and weight loss. Conclusion: Mitochondrial long chain fatty acid β-oxidation is critical for the maintenance of the brown adipocyte phenotype both during times of activation and quiescence. Keywords: Fatty acid oxidation, Brown adipose tissue, Cold induced thermogenesis, Adrenergic signaling, Adipose macrophage

  19. Movement and mortality of stocked brown trout in a stream

    DEFF Research Database (Denmark)

    Aarestrup, Kim; Jepsen, Niels; Koed, Anders

    2005-01-01

    The movement and mortality of stocked brown trout Salmo trutta were investigated using radio telemetry. Four brown trout left the study area whereas the remaining fish were stationary. After 5 weeks, 13 out of 50 tagged brown trout were still alive in the stream. Surviving fish had a significantly...

  20. Search for brown dwarfs in the IRAS data bases

    International Nuclear Information System (INIS)

    Low, F.J.

    1986-01-01

    A report is given on the initial searches for brown dwarf stars in the IRAS data bases. The paper was presented to the workshop on 'Astrophysics of brown dwarfs', Virginia, USA, 1985. To date no brown dwarfs have been discovered in the solar neighbourhood. Opportunities for future searches with greater sensitivity and different wavelengths are outlined. (U.K.)