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1
Shemerliuk, Yuliia, Yonghui Zhou, Zhaorong Yang, Gang Cao, Anja U. B. Wolter, Bernd Büchner, and Saicharan Aswartham. "Tuning Magnetic and Transport Properties in Quasi-2D (Mn1−xNix)2P2S6 Single Crystals." Electronic Materials 2, no. 3 (July 8, 2021): 284–98. http://dx.doi.org/10.3390/electronicmat2030020.
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We report an optimized chemical vapor transport method to grow single crystals of (Mn1−xNix)2P2S6 where x = 0, 0.3, 0.5, 0.7, and 1. Single crystals up to 4 mm × 3 mm × 200 μm were obtained by this method. As-grown crystals are characterized by means of scanning electron microscopy and powder X-ray diffraction measurements. The structural characterization shows that all crystals crystallize in monoclinic symmetry with the space group C2/m (No. 12). We have further investigated the magnetic properties of this series of single crystals. The magnetic measurements of the all as-grown single crystals show long-range antiferromagnetic order along all principal crystallographic axes. Overall, the Néel temperature TN is non-monotonous; with increasing Ni2+ doping, the temperature of the antiferromagnetic phase transition first decreases from 80 K for pristine Mn2P2S6 (x = 0) up to x = 0.5 and then increases again to 155 K for pure Ni2P2S6 (x = 1). The magnetic anisotropy switches from out-of-plane to in-plane as a function of composition in (Mn1−xNix)2P2S6 series. Transport studies under hydrostatic pressure on the parent compound Mn2P2S6 evidence an insulator-metal transition at an applied critical pressure of ~22 GPa.
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Kiselev, M. A., S. V. Levitsky, and V. A. Podobedov. "Safe engine-out landing of a passenger plane under the wind conditions." Civil Aviation High Technologies 22, no. 5 (October 28, 2019): 76–84. http://dx.doi.org/10.26467/2079-0619-2019-22-5-76-84.
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The engine failure, according to the flight safety inspection of the Federal Air Transport Agency, caused 4 of 6 aviation accidents in 2017, including 2 air disasters. In general, from 2001 to 2017, events related to the engine failure became the second most frequent cause of aviation accidents (13% of aviation accidents and 12% of air disasters). The worst consequences are associated with the engine failure at the most difficult and crucial stage of the flight landing. For example, it was the engine failure on the final approach that caused the crash of the L-410UVP-E20 RA-67047 aircraft near the Nelkan airfield on November 15, 2017. The article discusses a limiting situation in some sense – the landing of an aircraft with all failed engines under the wind conditions. The authors have proposed for this situation a methodology of calculating the landing approach of an aircraft under the wind conditions in case of failure of all engines of its power plant to an aerodrome equipped with an outer marker. The key features of such methodology are, firstly, the absence of necessity to link the path to the landmarks in the landing aerodrome area, and, secondly, the simplicity of the synthesis and the implementation of the aircraft control based on the proposed methodology during landing in both manual and director or automatic modes. To calculate the approach using the proposed methodology, the crew only needs to know the following values: the minimum drag airspeed on final approach, the height of the flight over an outer marker before landing and spiral approach leg. The content of the methodology in the article is illustrated by the results of the approach calculation when all of the main engines of the Russian short-medium-range MS-21 aircraft fail under the wind conditions.
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Adamchuk, V., V. Bulgakov, V. Nadykto, and I. Golovach. "Theory of motion controllability of a wheel machine-tractor aggregate." Agricultural Science and Practice 3, no. 2 (July 15, 2016): 3–10. http://dx.doi.org/10.15407/agrisp3.02.003.
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Aim. To obtain analytically new dependencies, determining the indicator of motion controllability of a wheel machine-tractor aggregate, taking into consideration external forces, constructive and kinematic parameters of the aggregate while the latter moves in the transport mode. Methods. The methods of tractor and vehicle theories, theoretical mechanics, the theory of dynamic stability, and methods of numeric computer calculations. Results. A new theory of motion controllability of a wheel machine-tractor aggregate during its non-linear mo- tion along the surface of the soil at an angle to the horizontal was elaborated. The analytic expressions for the determination of the actual indicator of aggregate controllability, including force and constructive parameters of a machine-tractor aggregate, affecting this indicator in the longitudinal-vertical plane were made. The ana- lytic expressions were obtained for the transport mode of the aggregate movement. The conditions, in which cross slips of the directive wheels of the tractor with implements in the longitudinal plane were analytically considered for the fi rst time. The analytic expressions for the determination of the required indicator of the controllability of the machine-tractor aggregate in the longitudinal plane, excluding any possibility of a cross slip of the aggregate while turning its directive wheels at a certain angle, were defi ned. Conclusions. Computer calculations demonstrated that during the non-linear movement along the surface of the soil at an angle of 12 ° to the horizontal the wheel machine-tractor aggregate will be controllable only if the wheel turning angles for the tractor with implements do not exceed 9 ° . In case of the working motion of this aggregate along the slope, its controllability is preserved on condition that the turning angle of directive wheels does not exceed 11 ° . It was established that the controllability of the wheel machine-tractor aggregate is determined by the actual λ d and required λ о indicators of controllability, which take into consideration the values of the vertical load on the directive wheels of the power source, the possibility of their turn in the longitudinal plane, and the pull during the deviation from rectilinear motion when it moves along the surface at an angle to the horizontal.
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Zhu, X. P., Q. Zhang, L. Ding, C. C. Zhang, Yu Isakova, A. Prima, A. Pushkarev, and M. K. Lei. "High-intensity pulsed ion beam focusing by its own space charge." Laser and Particle Beams 36, no. 4 (December 2018): 470–76. http://dx.doi.org/10.1017/s0263034618000514.
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AbstractThe paper presents the results of a study on propagation and focusing of high-intensity pulsed ion beams, produced by a self-magnetically insulated diode of semi-cylindrical geometry at the TEMP-6 accelerator (120 ns, 200–250 kV). We examined the space-charge neutralization of the beam, the energy density in the focus, the divergence of the beam, and its shot-to-shot displacement in the focal plane. It is found that the concentration of low-energy electrons in the beam is 1.3–1.5 times higher than the concentration of ions. We observed additional ion focusing by its own space charge. With an increase in the density of the net negative (electrons and ions) charge of the beam from 3.6 to 9 µC/cm2, the total divergence (the sum of the beam divergence in the vertical and horizontal planes) decreases from 11.4 to 4.5°. It leads to an increase in the energy density in the focus from 4 up to 10–12 J/cm2. To increase the electrons concentration in the beam, a metal grid installed in the ion beam transport region was used.
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Vreugdenhil, Catherine A., Bishakhdatta Gayen, and Ross W. Griffiths. "Transport by deep convection in basin-scale geostrophic circulation: turbulence-resolving simulations." Journal of Fluid Mechanics 865 (February 26, 2019): 681–719. http://dx.doi.org/10.1017/jfm.2019.64.
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Direct numerical simulations are used to investigate the nature of fully resolved small-scale convection and its role in large-scale circulation in a rotating $f$-plane rectangular basin with imposed surface temperature difference. The large-scale circulation has a horizontal geostrophic component and a deep vertical overturning. This paper focuses on convective circulation with no wind stress, and buoyancy forcing sufficiently strong to ensure turbulent convection within the thermal boundary layer (horizontal Rayleigh numbers $Ra\approx 10^{12}{-}10^{13}$). The dynamics are found to depend on the value of a convective Rossby number, $Ro_{\unicode[STIX]{x0394}T}$, which represents the strength of buoyancy forcing relative to Coriolis forces. Vertical convection shifts from a mean endwall plume under weak rotation ($Ro_{\unicode[STIX]{x0394}T}>10^{-1}$) to ‘open ocean’ chimney convection plus mean vertical plumes at the side boundaries under strong rotation ($Ro_{\unicode[STIX]{x0394}T}<10^{-1}$). The overall heat throughput, horizontal gyre transport and zonally integrated overturning transport are then consistent with scaling predictions for flow constrained by thermal wind balance in the thermal boundary layer coupled to vertical advection–diffusion balance in the boundary layer. For small Rossby numbers relevant to circulation in an ocean basin, vertical heat transport from the surface layer into the deep interior occurs mostly in ‘open ocean’ chimney convection while most vertical mass transport is against the side boundaries. Both heat throughput and the mean circulation (in geostrophic gyres, boundary currents and overturning) are reduced by geostrophic constraints.
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Apatenkov, S. V., V. A. Sergeev, M. V. Kubyshkina, R. Nakamura, W. Baumjohann, A. Runov, I. Alexeev, et al. "Multi-spacecraft observation of plasma dipolarization/injection in the inner magnetosphere." Annales Geophysicae 25, no. 3 (March 29, 2007): 801–14. http://dx.doi.org/10.5194/angeo-25-801-2007.
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Abstract. Addressing the origin of the energetic particle injections into the inner magnetosphere, we investigate the 23 February 2004 substorm using a favorable constellation of four Cluster (near perigee), LANL and Geotail spacecraft. Both an energy-dispersed and a dispersionless injection were observed by Cluster crossing the plasma sheet horn, which mapped to 9–12 RE in the equatorial plane close to the midnight meridian. Two associated narrow equatorward auroral tongues/streamers propagating from the oval poleward boundary could be discerned in the global images obtained by IMAGE/WIC. As compared to the energy-dispersed event, the dispersionless injection front has important distinctions consequently repeated at 4 spacecraft: a simultaneous increase in electron fluxes at energies ~1..300 keV, ~25 nT increase in BZ and a local increase by a factor 1.5–1.7 in plasma pressure. The injected plasma was primarily of solar wind origin. We evaluated the change in the injected flux tube configuration during the dipolarization by fitting flux increases observed by the PEACE and RAPID instruments, assuming adiabatic heating and the Liouville theorem. Mapping the locations of the injection front detected by the four spacecraft to the equatorial plane, we estimated the injection front thickness to be ~1 RE and the earthward propagation speed to be ~200–400 km/s (at 9–12 RE). Based on observed injection properties, we suggest that it is the underpopulated flux tubes (bubbles with enhanced magnetic field and sharp inner front propagating earthward), which accelerate and transport particles into the strong-field dipolar region.
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NAKANISHI, T., N. MOTOYAMA, H. MITAMURA, N. TAKESHITA, H. TAKAHASHI, H. EISAKI, S. UCHIDA, and N. MÔRI. "RESISTIVE UPPER CRITICAL FIELD OF SUPERCONDUCTING SPIN-LADDER Sr14-xCaxCu24O41." International Journal of Modern Physics B 14, no. 29n31 (December 20, 2000): 3617–22. http://dx.doi.org/10.1142/s0217979200004131.
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We report the resistive upper critical field Hc2(T) of the hole-doped two-leg ladder Sr 14-x Ca x Cu 24 O 41(x=12) single crystal, which becomes superconducting with Tc~5 K in a pressure range above ~3.0 GPa . Using a newly developed compact high-pressure cell, the magneto-transport measurements have been performed at temperatures down to ~140 mK under high pressure above 3.5 GPa. It is found that Hc2 (perpendicular to the ladder Cu 2 O 3 plane) increases anomalously as the temperature is decreased having an upward curvature and shows no saturation down to T/T c ~ 0.03. Also, its temperature dependence is found to resemble that of the high-Tc superconducting oxide Tl 2 Ba 2 CuO 6. This fact suggests that the anomalous behavior of Hc2 has a common origin between the ladders and the two-dimensional high-Tc superconducting oxides.
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Yaremchuk, M., D. Nechaev, J. Schroter, and E. Fahrbach. "A dynamically consistent analysis of circulation and transports in the southwestern Weddell Sea." Annales Geophysicae 16, no. 8 (August 31, 1998): 1024–38. http://dx.doi.org/10.1007/s00585-998-1024-7.
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Abstract. An inverse model is applied for the analysis of hydrographic and current meter data collected on the repeat WOCE section SR4 in the Weddell Sea in 1989–1992. The section crosses the Weddell Sea cyclonic gyre from Kapp Norvegia to the northern end of the Antarctic Peninsula. The concepts of geostrophy, conservation of planetary vorticity and hydrostatics are combined with advective balances of active and passive properties to provide a dynamically consistent circulation pattern. Our variational assimilation scheme allows the calculation of three-dimensional velocities in the section plane. Current speeds are small except along the coasts where they reach up to 12 cm/s. We diagnose a gyre transport of 34 Sverdrup which is associated with a poleward heat transport of 28×1012 W corresponding to an average heat flux of 15 Wm–2 in the Weddell Sea south of the transect. This exceeds the estimated local flux on the transect of 2 Wm–2. As the transect is located mostly in the open ocean, we conclude that the shelf areas contribute significantly to the ocean-atmosphere exchange and are consequently key areas for the contribution of the Weddell Sea to global ocean ventilation. Conversion of water masses occuring south of the section transform 6.6±1.1 Sv of the inflowing warm deep water into approximately equal amounts of Weddell Sea deep water and Weddell Sea bottom water. The volume transport of surface water equals in the in- and outflow. This means that almost all newly formed surface water is involved in the deep and bottom water formation. Comparison with the results obtained by pure velocity interpolation combined with a hydrographic data subset indicates major differences in the derived salt transports and the water mass conversion of the surface water. The differences can be explained by deviations in the structure of the upper ocean currents to which shelf areas contribute significantly. Additionally a rigorous variance analysis is performed. When only hydrographic data are used for the inversion both the gyre transport and the poleward heat transport are substantially lower. They amount to less than 40% of our best estimate while the standard deviations of both quantities are 6.5 Sv and 37×1012 W, respectively. With the help of long-term current meter measurements these errors can be reduced to 2 Sv and 8×1012 W. Our result underlines the importance of velocity data or equivalent information that helps to estimate the absolute velocities.Key words. Oceanography: General (Arctic and antarctic oceanography) · Oceanography: Physical (General circulation; Hydrography)
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Bulgakov, Volodymyr, Valerii Adamchuk, Volodymyr Nadykto, Volodymyr Kyurchev, and Ladislav Nozdrovický. "Theoretical Consideration of The Controllability Indicator of Machine-Tractor Unit Movement." Acta Technologica Agriculturae 20, no. 1 (March 1, 2017): 11–18. http://dx.doi.org/10.1515/ata-2017-0003.
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Abstract The paper is focused on the issues of controllability of machine-tractor units based on wheel-type tractors during their non-straight driving on the soil surface, which is positioned at an angle to the horizon. There were obtained analytical expressions for the determination of the actual indicator of control λd, including both the power and the design parameters of the machine-tractor unit, which affect the abovementioned indicator in the longitudinal vertical plane. These expressions are obtained for the tractor driving on both road and also driving during field operation. In addition, the paper discusses the conditions under which there may occur the cross-slip of the tractor steering wheels in the transversal horizontal plane. As a result of this review, there were obtained the analytical expressions for determining the required indicator of the controllability λd of machine-tractor unit in the horizontal plane, excluding the possibility of lateral sliding of the unit by turning its steering wheels at a certain angle. These expressions are obtained for the two modes of the machine-tractor unit: for driving during transport on the road and during the operation in the field. The machine-tractor unit based on the wheel-type tractor with rear mounted 3-mouldboard plough was analytically investigated. By means of computer calculations, there was observed the fact that when moving in non-straight direction on the soil surface, inclined to the horizon at an angle of 12°, the machine-tractor unit is controllable only when the angles of the steering wheel of the given tractor do not exceed 9°. During the working movement (ploughing) of the given machine-tractor unit on an inclined field surface, its controllability will be preserved on condition that the angle of the tractor steering wheels does not exceed 11°. According to obtained results, it can be stated that the controllability of the machine-tractor unit is determined by the indicator of controllability, taking into account the value of the vertical load acting on the tractor steering wheels, the possibility of their turning in the horizontal plane, as well as the withdrawal of the machine-tractor unit from rectilinear motion and its movement on the field surface, inclined at an angle to the horizon.
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Matsuuchi, L., KM Buckley, AW Lowe, and RB Kelly. "Targeting of secretory vesicles to cytoplasmic domains in AtT-20 and PC-12 cells." Journal of Cell Biology 106, no. 2 (February 1, 1988): 239–51. http://dx.doi.org/10.1083/jcb.106.2.239.
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Organelles are not uniformly distributed throughout the cytoplasm but have preferred locations that vary between tissues and during development. To investigate organelle targeting to cytoplasmic domains we have taken advantage of the mouse pituitary cell line, AtT-20, which, when induced to extend long processes, accumulates dense core secretory granules at the tips of the processes. During mitosis, these secretory granules accumulate along the plane of division. Protein synthesis is not mandatory for such redistribution of secretory granules. To explore the specificity of the redistribution we have used transfected AtT-20 cells that express the immunoglobulin kappa light chain. While the endogenous hormone ACTH is found in secretory granules, the kappa chain is a marker for organelles involved in constitutive secretion. By immunofluorescence, kappa also accumulates at the tips of growing processes, and along the midline of dividing cells, suggesting that the redistribution of vesicles is not specific for dense-core secretory granules. Since there is evidence for selective organelle transport along processes in neuronal cells, the rat pheochromocytoma cell PC-12 was transfected with DNA encoding markers for regulated and constitutive secretory vesicles. Again regulated and constitutive vesicles co-distribute, even in cells grown in the presence of nerve growth factor. We suggest that at least in the cells studied here, cytoskeletal elements normally carry exocytotic organelles to the surface; when the cytoskeletal elements coalesce in an extending process, exocytotic organelles of both the constitutive and regulated pathway are transported nonselectively to the tips of the cytoskeletal elements where they accumulate.
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Schuldiner, S., M. Lebendiker, and H. Yerushalmi. "EmrE, the smallest ion-coupled transporter, provides a unique paradigm for structure-function studies." Journal of Experimental Biology 200, no. 2 (January 1, 1997): 335–41. http://dx.doi.org/10.1242/jeb.200.2.335.
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EmrE is an Escherichia coli multidrug transporter which confers resistance to a wide variety of toxicants by actively removing them in exchange for hydrogen ions. EmrE is a highly hydrophobic 12 kDa protein which has been purified by taking advantage of its unique solubility in organic solvents. After solubilization and purification, the protein retains its ability to transport as judged from the fact that it can be reconstituted in a functional form. Hydrophobicity analysis of the sequence yielded four putative transmembrane domains of similar sizes. Results from transmission Fourier transform infrared measurements agree remarkably well with this hypothesis and yielded alpha-helical estimates of 78% and 80% for EmrE in CHCl3:MeOH and 1,2-dimyristoyl phosphocholine, respectively. Furthermore, the fact that most of the amide groups in the protein do not undergo amide-proton H/D exchange implies that most (approximately 80%) of the residues are embedded in the bilayer. These observations are only consistent with four transmembrane helices. A domain lined by Cys41 and Cys95 accessible only to substrates such as the organic mercurial 4-(chloromercuri)benzoic acid has been identified. Both residues are asymmetric in their location with respect to the plane of the membrane, Cys95 being closer than Cys41 to the outside face of the membrane. In co-reconstitution experiments of wild-type protein with three different inactive mutants, negative dominance has been observed. This phenomenon suggests that EmrE is functional as a homo-oligomer.
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Felix, Victor Barbosa, Douglas Fabichack Jr., Paulo Rogério Celline, and Arlindo Tribess. "Sistema de Ventilação Personalizada Instalado na Poltrona em Cabine de Aeronave: Análise da Concentração e da Eficiência na Remoção de Partículas Expiratórias." REVISTA PLURI 1, no. 3 (August 13, 2020): 77. http://dx.doi.org/10.26843/rpv132020p77-86.
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As pessoas viajam cada vez mais de avião e, muitas vezes, estas viagens são longas. A qualidade do ar dentro desse meio de transporte torna-se então uma questão crucial, principalmente agora que o mundo está passando por uma pandemia causada pela COVID 19. Uma forma de melhorar a qualidade do ar e as condições de conforto térmico dentro de uma cabine de aeronave está na utilização de novos sistemas de ventilação personalizada. No presente trabalho é apresentada análise experimental da influência de um sistema de ventilação personalizada (PV) na concentração e na eficiência de remoção de partículas expiratórias em cabine de aeronave com sistema de ventilação convencional por mistura (MV). Os ensaios foram realizados em um mock-up com 12 lugares, com três fileiras de quatro poltronas. Medições de concentração de partículas foram realizadas na região de respiração, a 1,10m do piso, em todos os assentos da cabine. Os resultados mostram que a eficiência na remoção de partículas na região de respiração, considerando toda a cabine, é de até 25% para partículas de 5 a 10 μm e de até 30% para partículas de 2 a 5μm. Os resultados mostram também que a eficiência na remoção de partículas é praticamente igual para o sistema PV operando tanto no assento da janela quanto no assento do corredor para todos os tamanhos de partículas. Os resultados da eficiência de remoção de partículas mostram que o sistema PV influencia significativamente a remoção de partículas no assento no qual o sistema está operando e na cabine como um todo.Palavras-chave: Sistemas de Ventilação, Qualidade do Ar, Partículas Expiratórias, Análise Experimental, Cabines de AeronavesAbstractPeople travel more and more by plane, and often these trips are long. Air quality within this mode of transport then becomes a crucial issue, especially now that the world is experiencing a pandemic caused by COVID 19. A way to improve air quality and thermal comfort conditions inside a cabin of aircraft is in the use of new personalized ventilation systems. This work presents an experimental analysis of the influence of a personalized ventilation system (PV) on the concentration and efficiency of removal of expiratory particles in an aircraft cabin with a conventional mixing ventilation system (MV). The tests were carried out in a mock-up with 12 seats, three rows with four abreast. Measurements of particle concentration were performed in the breathing region, 1.10 m from the floor, in all seats of the cabin. The results show that the efficiency in removing particles in the breathing region, considering the entire cabin, is up to 25% for particles of 5 to 10 μm and up to 30% for particles of 2 to 5 μm. The results also show that particle removal efficiency is practically the same for the PV system operating on both the window seat and the aisle seat for all particle sizes. The results of particle removal efficiency show that the PV system significantly influences the removal of particles in the seat on which the system is perating and in the cab as a whole.Keyworks: Ventilation systems, Air Quality, Expiratory droplets, Experimental analysis, Aircraft cabins
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Grosvenor, Daniel P., Odran Sourdeval, and Robert Wood. "Parameterizing cloud top effective radii from satellite retrieved values, accounting for vertical photon transport: quantification and correction of the resulting bias in droplet concentration and liquid water path retrievals." Atmospheric Measurement Techniques 11, no. 7 (July 20, 2018): 4273–89. http://dx.doi.org/10.5194/amt-11-4273-2018.
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Abstract. Droplet concentration (Nd) and liquid water path (LWP) retrievals from passive satellite retrievals of cloud optical depth (τ) and effective radius (re) usually assume the model of an idealized cloud in which the liquid water content (LWC) increases linearly between cloud base and cloud top (i.e. at a fixed fraction of the adiabatic LWC). Generally it is assumed that the retrieved re value is that at the top of the cloud. In reality, barring re retrieval biases due to cloud heterogeneity, the retrieved re is representative of smaller values that occur lower down in the cloud due to the vertical penetration of photons at the shortwave-infrared wavelengths used to retrieve re. This inconsistency will cause an overestimate of Nd and an underestimate of LWP (referred to here as the “penetration depth bias”), which this paper quantifies via a parameterization of the cloud top re as a function of the retrieved re and τ. Here we estimate the relative re underestimate for a range of idealized modelled adiabatic clouds using bispectral retrievals and plane-parallel radiative transfer. We find a tight relationship between gre=recloud top/reretrieved and τ and that a 1-D relationship approximates the modelled data well. Using this relationship we find that gre values and hence Nd and LWP biases are higher for the 2.1 µm channel re retrieval (re2.1) compared to the 3.7 µm one (re3.7). The theoretical bias in the retrieved Nd is very large for optically thin clouds, but rapidly reduces as cloud thickness increases. However, it remains above 20 % for τ<19.8 and τ<7.7 for re2.1 and re3.7, respectively. We also provide a parameterization of penetration depth in terms of the optical depth below cloud top (dτ) for which the retrieved re is likely to be representative. The magnitude of the Nd and LWP biases for climatological data sets is estimated globally using 1 year of daily MODIS (MODerate Imaging Spectroradiometer) data. Screening criteria are applied that are consistent with those required to help ensure accurate Nd and LWP retrievals. The results show that the SE Atlantic, SE Pacific and Californian stratocumulus regions produce fairly large overestimates due to the penetration depth bias with mean biases of 32–35 % for re2.1 and 15–17 % for re3.7. For the other stratocumulus regions examined the errors are smaller (24–28 % for re2.1 and 10–12 % for re3.7). Significant time variability in the percentage errors is also found with regional mean standard deviations of 19–37 % of the regional mean percentage error for re2.1 and 32–56 % for re3.7. This shows that it is important to apply a daily correction to Nd for the penetration depth error rather than a time–mean correction when examining daily data. We also examine the seasonal variation of the bias and find that the biases in the SE Atlantic, SE Pacific and Californian stratocumulus regions exhibit the most seasonality, with the largest errors occurring in the December, January and February (DJF) season. LWP biases are smaller in magnitude than those for Nd (−8 to −11 % for re2.1 and −3.6 to −6.1 % for re3.7). In reality, and especially for more heterogeneous clouds, the vertical penetration error will be combined with a number of other errors that affect both the re and τ, which are potentially larger and may compensate or enhance the bias due to vertical penetration depth. Therefore caution is required when applying the bias corrections; we suggest that they are only used for more homogeneous clouds.
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Tobalske, B. W., W. L. Peacock, and K. P. Dial. "Kinematics of flap-bounding flight in the zebra finch over a wide range of speeds." Journal of Experimental Biology 202, no. 13 (July 1, 1999): 1725–39. http://dx.doi.org/10.1242/jeb.202.13.1725.
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It has been proposed elsewhere that flap-bounding, an intermittent flight style consisting of flapping phases interspersed with flexed-wing bounds, should offer no savings in average mechanical power relative to continuous flapping unless a bird flies 1.2 times faster than its maximum range speed (Vmr). Why do some species use intermittent bounds at speeds slower than 1.2Vmr? The ‘fixed-gear hypothesis’ suggests that flap-bounding is used to vary mean power output in small birds that are otherwise constrained by muscle physiology and wing anatomy to use a fixed muscle shortening velocity and pattern of wing motion at all flight speeds; the ‘body-lift hypothesis’ suggests that some weight support during bounds could make flap-bounding flight aerodynamically advantageous in comparison with continuous flapping over most forward flight speeds. To test these predictions, we studied high-speed film recordings (300 Hz) of wing and body motion in zebra finches (Taenopygia guttata, mean mass 13.2 g, N=4) taken as the birds flew in a variable-speed wind tunnel (0–14 m s-1). The zebra finches used flap-bounding flight at all speeds, so their flight style was unique compared with that of birds that facultatively shift from continuous flapping or flap-gliding at slow speeds to flap-bounding at fast speeds. There was a significant effect of flight speed on all measured aspects of wing motion except percentage of the wingbeat spent in downstroke. Changes in angular velocity of the wing indicated that contractile velocity in the pectoralis muscle changed with flight speed, which is not consistent with the fixed-gear hypothesis. Although variation in stroke-plane angle relative to the body, pronation angle of the wing and wing span at mid-upstroke showed that the zebra finch changed within-wingbeat geometries according to speed, a vortex-ring gait with a feathered upstroke appeared to be the only gait used during flapping. In contrast, two small species that use continuous flapping during slow flight (0–4 m s-1) either change wingbeat gait according to flight speed or exhibit more variation in stroke-plane and pronation angles relative to the body. Differences in kinematics among species appear to be related to wing design (aspect ratio, skeletal proportions) rather than to pectoralis muscle fiber composition, indicating that the fixed-gear hypothesis should perhaps be modified to exclude muscle physiology and to emphasize constraints due to wing anatomy. Body lift was produced during bounds at speeds from 4 to 14 m s-1. Maximum body lift was 0.0206 N (15.9 % of body weight) at 10 m s-1; body lift:drag ratio declined with increasing air speed. The aerodynamic function of bounds differed with increasing speed from an emphasis on lift production (4–10 m s-1) to an emphasis on drag reduction with a slight loss in lift (12 and 14 m s-1). From a mathematical model of aerodynamic costs, it appeared that flap-bounding offered the zebra finch an aerodynamic advantage relative to continuous flapping at moderate and fast flight speeds (6–14 m s-1), with body lift augmenting any savings offered solely by flap-bounding at speeds faster than 7.1 m s-1. The percentage of time spent flapping during an intermittent flight cycle decreased with increasing speed, so the mechanical cost of transport was likely to be lowest at faster flight speeds (10–14 m s-1).
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Fauchez, Thomas, Steven Platnick, Tamás Várnai, Kerry Meyer, Céline Cornet, and Frédéric Szczap. "Scale dependence of cirrus heterogeneity effects. Part II: MODIS NIR and SWIR channels." Atmospheric Chemistry and Physics 18, no. 16 (August 22, 2018): 12105–21. http://dx.doi.org/10.5194/acp-18-12105-2018.
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Abstract. In a context of global climate change, the understanding of the radiative role of clouds is crucial. On average, ice clouds such as cirrus have a significant positive radiative effect, but under some conditions the effect may be negative. However, many uncertainties remain regarding the role of ice clouds on Earth's radiative budget and in a changing climate. Global satellite observations are particularly well suited to monitoring clouds, retrieving their characteristics and inferring their radiative impact. To retrieve ice cloud properties (optical thickness and ice crystal effective size), current operational algorithms assume that each pixel of the observed scene is plane-parallel and homogeneous, and that there is no radiative connection between neighboring pixels. Yet these retrieval assumptions are far from accurate, as real radiative transfer is 3-D. This leads to the plane-parallel and homogeneous bias (PPHB) plus the independent pixel approximation bias (IPAB), which impacts both the estimation of top-of-the-atmosphere (TOA) radiation and the retrievals. An important factor that determines the impact of these assumptions is the sensor spatial resolution. High-spatial-resolution pixels can better represent cloud variability (low PPHB), but the radiative path through the cloud can involve many pixels (high IPAB). In contrast, low-spatial-resolution pixels poorly represent the cloud variability (high PPHB), but the radiation is better contained within the pixel field of view (low IPAB). In addition, the solar and viewing geometry (as well as cloud optical properties) can modulate the magnitude of the PPHB and IPAB. In this, Part II of our study, we simulate TOA 0.86 and 2.13 µm solar reflectances over a cirrus uncinus scene produced by the 3DCLOUD model. Then, 3-D radiative transfer simulations are performed with the 3DMCPOL code at spatial resolutions ranging from 50 m to 10 km, for 12 viewing geometries and nine solar geometries. It is found that, for simulated nadir observations taken at resolution higher than 2.5 km, horizontal radiation transport (HRT) dominates biases between 3-D and 1-D reflectance calculations, but these biases are mitigated by the side illumination and shadowing effects for off-zenith solar geometries. At resolutions coarser than 2.5 km, PPHB dominates. For off-nadir observations at resolutions higher than 2.5 km, the effect that we call THEAB (tilted and homogeneous extinction approximation bias) due to the oblique line of sight passing through many cloud columns contributes to a large increase of the reflectances, but 3-D radiative effects such as shadowing and side illumination for oblique Sun are also important. At resolutions coarser than 2.5 km, the PPHB is again the dominant effect. The magnitude and resolution dependence of PPHB and IPAB is very different for visible, near-infrared and shortwave infrared channels compared with the thermal infrared channels discussed in Part I of this study. The contrast of 3-D radiative effects between solar and thermal infrared channels may be a significant issue for retrieval techniques that simultaneously use radiative measurements across a wide range of solar reflectance and infrared wavelengths.
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Ballarotta, M., S. Falahat, L. Brodeau, and K. Döös. "On the glacial and interglacial thermohaline circulation and the associated transports of heat and freshwater." Ocean Science 10, no. 6 (November 19, 2014): 907–21. http://dx.doi.org/10.5194/os-10-907-2014.
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Abstract. The thermohaline circulation (THC) and the oceanic heat and freshwater transports are essential for understanding the global climate system. Streamfunctions are widely used in oceanography to represent the THC and estimate the transport of heat and freshwater. In the present study, the regional and global changes of the THC, the transports of heat and freshwater and the timescale of the circulation between the Last Glacial Maximum (LGM, ≈ 21 kyr ago) and the present-day climate are explored using an Ocean General Circulation Model and streamfunctions projected in various coordinate systems. We found that the LGM tropical circulation is about 10% stronger than under modern conditions due to stronger wind stress. Consequently, the maximum tropical transport of heat is about 20% larger during the LGM. In the North Atlantic basin, the large sea-ice extent during the LGM constrains the Gulf Stream to propagate in a more zonal direction, reducing the transport of heat towards high latitudes by almost 50% and reorganising the freshwater transport. The strength of the Atlantic Meridional Overturning Circulation depends strongly on the coordinate system. It varies between 9 and 16 Sv during the LGM, and between 12 to 19 Sv for the present day. Similar to paleo-proxy reconstructions, a large intrusion of saline Antarctic Bottom Water takes place into the Northern Hemisphere basins and squeezes most of the Conveyor Belt circulation into a shallower part of the ocean. These different haline regimes between the glacial and interglacial period are illustrated by the streamfunctions in latitude–salinity coordinates and thermohaline coordinates. From these diagnostics, we found that the LGM Conveyor Belt circulation is driven by an enhanced salinity contrast between the Atlantic and the Pacific basin. The LGM abyssal circulation lifts and makes the Conveyor Belt cell deviate from the abyssal region, resulting in a ventilated upper layer above a deep stagnant layer, and an Atlantic circulation more isolated from the Pacific. An estimate of the timescale of the circulation reveals a sluggish abyssal circulation during the LGM, and a Conveyor Belt circulation that is more vigorous due to the combination of a stronger wind stress and a shortened circulation route.
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Boysen, Nils, Dirk Briskorn, and Stefan Schwerdfeger. "Walk the Line: Optimizing the Layout Design of Moving Walkways." Transportation Science 55, no. 4 (July 2021): 908–29. http://dx.doi.org/10.1287/trsc.2021.1051.
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A moving walkway (also denoted as moving sidewalk, travelator, autowalk, pedestrian conveyor, or skywalk) is a slow moving conveyor that transports standing or walking people horizontally over a short to medium distance. Constantly moving walkways have a long-lasting tradition especially inside large buildings, such as airport terminals and railway stations. Novel technological developments allow to accelerate walkways in their middle sections up to 12 km/h, while still providing a safe and much slower entrance and exit. Furthermore, first applications of moving walkways as environmentally friendly and space-efficient alternatives for urban public transport exist. In this context, our paper aims to support the layout design of moving walkways with optimization. Given a straight corridor (e.g., an airport terminal) and the passenger flows within the corridor (e.g., among gates), we aim to optimally place bidirectional walkway segments. We show that the resulting optimization problem is efficiently solvable by dynamic programming even if multiple relevant extensions, such as multiple objectives, budget constraints, and minimum safety distances, among subsequent segments are relevant. We apply our algorithm to explore the impact of constantly moving and accelerating walkways on total travel times and benchmark solutions without walkway support in a real-world case study. Our results reveal that wrongly placed walkways may considerably slow down passenger transport, but a very simple design rule leads to near-optimal results.
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Gavrin, Aleksandr, Patrick C. Loughlin, Ella Brear, Oliver W. Griffith, Frank Bedon, Marianne Suter Grotemeyer, Viviana Escudero, et al. "Soybean Yellow Stripe-like 7 is a symbiosome membrane peptide transporter important for nitrogen fixation." Plant Physiology 186, no. 1 (February 5, 2021): 581–98. http://dx.doi.org/10.1093/plphys/kiab044.
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Abstract Legumes form a symbiosis with rhizobia that convert atmospheric nitrogen (N2) to ammonia and provide it to the plant in return for a carbon and nutrient supply. Nodules, developed as part of the symbiosis, harbor rhizobia that are enclosed in a plant-derived symbiosome membrane (SM) to form an organelle-like structure called the symbiosome. In mature nodules exchanges between the symbionts occur across the SM. Here we characterize Yellow Stripe-like 7 (GmYSL7), a Yellow stripe-like family member localized on the SM in soybean (Glycine max) nodules. It is expressed specifically in infected cells with expression peaking soon after nitrogenase becomes active. Unlike most YSL family members, GmYSL7 does not transport metals complexed with phytosiderophores. Rather, it transports oligopeptides of between four and 12 amino acids. Silencing GmYSL7 reduces nitrogenase activity and blocks infected cell development so that symbiosomes contain only a single bacteroid. This indicates the substrate of YSL7 is required for proper nodule development, either by promoting symbiosome development directly or by preventing inhibition of development by the plant. RNAseq of nodules where GmYSL7 was silenced suggests that the plant initiates a defense response against rhizobia with genes encoding proteins involved in amino acid export downregulated and some transcripts associated with metal homeostasis altered. These changes may result from the decrease in nitrogen fixation upon GmYSL7 silencing and suggest that the peptide(s) transported by GmYSL7 monitor the functional state of the bacteroids and regulate nodule metabolism and transport processes accordingly. Further work to identify the physiological substrate for GmYSL7 will allow clarification of this role.
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Bertram, T. H., A. E. Perring, P. J. Wooldridge, J. Dibb, M. A. Avery, and R. C. Cohen. "On the export of reactive nitrogen from Asia: NO<sub>x</sub> partitioning and effects on ozone." Atmospheric Chemistry and Physics Discussions 12, no. 9 (September 21, 2012): 24955–84. http://dx.doi.org/10.5194/acpd-12-24955-2012.
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Abstract. The partitioning of reactive nitrogen (NOy) was measured over the remote North Pacific during spring 2006. We use these observations to assess the impact of increasing emissions of nitrogen oxides in East Asia on ozone (O3) production rates over the remote Pacific and the intercontinental transport of O3 and its precursors to North America. Aircraft observations of speciated NOy, made between 25° and 55° N, confirm a controlling role for peroxyacyl nitrates in NOx production in aged Asian outflow, accounting for more than 60% of NOy above 5 km, while thermal dissociation limits their contribution to less than 10% in the lower troposphere. The observations reveal the extreme sensitivity of the remote Pacific to future changes in NOx loadings, with an experimentally determined crossover point between net Oxdestruction and net Ox production of 60 pptv NOx. Using simultaneous observations of speciated NOy and wind speed, we calculate the flux of reactive nitrogen through the meridional plane of 150° W (between 25° and 55° N) to be 0.007 ± 0.002 Tg N day−1, which provides an upper limit of 15% on the export efficiency of NOy from East Asia. Analysis of the subsiding plumes in the sampling domains suggests that episodic dry subsidence events play an important role in the intercontinental transport of ozone and its precursors from East Asia to North America.
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Giglio, Donata, Dean Roemmich, and Sarah T. Gille. "Wind-Driven Variability of the Subtropical North Pacific Ocean." Journal of Physical Oceanography 42, no. 12 (December 1, 2012): 2089–100. http://dx.doi.org/10.1175/jpo-d-12-029.1.
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Abstract The Argo array provides a unique dataset to explore variability of the subsurface ocean interior. This study considers the subtropical North Pacific Ocean during the period from 2004 to 2011, when Argo coverage has been relatively complete in time and space. Two distinct patterns of Argo dynamic height transport function () are observed: in 2004/05, the gyre is stronger, and in 2008/09 it is weaker. The orientation of the subtropical gyre also shifts over time: the predominantly zonal major axis shifts to a more northwest–southeast orientation in 2004/05 and to a more southwest–northeast orientation in 2008/09. The limited temporal range of the Argo observations does not allow analysis of the correlation of ocean transport and wind forcing in the basin for the multiyear time scale (6–8-yr period) typical of the dominant gyre patterns. The meridional geostrophic transport anomaly between 180° and 150°E is computed both from Argo data (0–2000 db) and from the Sverdrup relation (using reanalysis winds): similarities are observed in a latitude–time plane, consistent with local forcing playing an important role. A forcing contribution from the eastern subtropics will also reach the region of interest, but on a longer time scale, and it is not analyzed in this study. Compared with the 8-yr Argo record, the longer 19-yr time series of satellite altimetry shows a similar but somewhat modified pattern of variability. A longer Argo record will be needed to observe the decadal-scale fluctuations, to separate interannual and decadal signals, and to ensure statistical confidence in relating the wind forcing and the oceanic response.
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Weerakoon, Dilan R., and Jonathan W. Olson. "The Campylobacter jejuni NADH:Ubiquinone Oxidoreductase (Complex I) Utilizes Flavodoxin Rather than NADH." Journal of Bacteriology 190, no. 3 (December 7, 2007): 915–25. http://dx.doi.org/10.1128/jb.01647-07.
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ABSTRACT Campylobacter jejuni encodes 12 of the 14 subunits that make up the respiratory enzyme NADH:ubiquinone oxidoreductase (also called complex I). The two nuo genes not present in C. jejuni encode the NADH dehydrogenase, and in their place in the operon are the novel genes designated Cj1575c and Cj1574c. A series of mutants was generated in which each of the 12 nuo genes (homologues to known complex I subunits) was disrupted or deleted. Each of the nuo mutants will not grow in amino acid-based medium unless supplemented with an alternative respiratory substrate such as formate. Unlike the nuo genes, Cj1574c is an essential gene and could not be disrupted unless an intact copy of the gene was provided at an unrelated site on the chromosome. A nuo deletion mutant can efficiently respire formate but is deficient in α-ketoglutarate respiratory activity compared to the wild type. In C. jejuni, α-ketoglutarate respiration is mediated by the enzyme 2-oxoglutarate:acceptor oxidoreductase; mutagenesis of this enzyme abolishes α-ketoglutarate-dependent O2 uptake and fails to reduce the electron transport chain. The electron acceptor for 2-oxoglutarate:acceptor oxidoreductase was determined to be flavodoxin, which was also determined to be an essential protein in C. jejuni. A model is presented in which CJ1574 mediates electron flow into the respiratory transport chain from reduced flavodoxin and through complex I.
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Huang, Jing, and Elie Bou-Zeid. "Turbulence and Vertical Fluxes in the Stable Atmospheric Boundary Layer. Part I: A Large-Eddy Simulation Study." Journal of the Atmospheric Sciences 70, no. 6 (May 29, 2013): 1513–27. http://dx.doi.org/10.1175/jas-d-12-0167.1.
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Abstract This study seeks to quantitatively and qualitatively understand how stability affects transport in the continuously turbulent stably stratified atmospheric boundary layer, based on a suite of large-eddy simulations. The test cases are based on the one adopted by the Global Energy and Water Cycle Experiment (GEWEX) Atmospheric Boundary Layer Study (GABLS) project, but with a largely expanded stability range where the gradient Richardson number (Rig) reaches up to around 1. The analysis is mainly focused on understanding the modification of turbulent structures and dynamics with increasing stability in order to improve the modeling of the stable atmospheric boundary layer in weather and climate models, a topic addressed in Part II of this work. It is found that at quasi equilibrium, an increase in stability results in stronger vertical gradients of the mean temperature, a lowered low-level jet, a decrease in vertical momentum transport, an increase in vertical buoyancy flux, and a shallower boundary layer. Analysis of coherent turbulent structures using two-point autocorrelation reveals that the autocorrelation of the streamwise velocity is horizontally anisotropic while the autocorrelation of the vertical velocity is relatively isotropic in the horizontal plane and its integral length scale decreases as stability increases. The effects of stability on the overall turbulent kinetic energy (TKE) and its budget terms are also investigated, and it is shown that the authors' large-eddy simulation results are in good agreement with previous experimental findings across varied stabilities. Finally, Nieuwstadt's local-scaling theory is reexamined and it is concluded that the height z is not a relevant scaling parameter and should be replaced by a constant length scale away from the surface, indicating that the z-less range starts lower than previously assumed.
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Zhao, Xin, Nannan Li, Qin Song, Xiaohong Li, Hongjun Meng, and Keming Luo. "OPDAT1, a plastid envelope protein involved in 12-oxo-phytodienoic acid export for jasmonic acid biosynthesis in Populus." Tree Physiology 41, no. 9 (April 9, 2021): 1714–28. http://dx.doi.org/10.1093/treephys/tpab037.
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Abstract Twelve-oxo-phytodienoic acid (OPDA), the cyclopentenone precursor of jasmonic acid (JA), is required for the wounding response of plants. OPDA is derived from plastid-localized α-linolenic acid (α-LeA; 18:3) via the octadecanoid pathway, and is further exported from plastids to the cytosol for JA biosynthesis. However, the mechanism of OPDA transport from plastids has yet to be elucidated. In the current study, a plastid inner envelope-localized protein, designated 12-oxo-Phtyodienoic Acid Transporter 1 (OPDAT1), was identified and shown to potentially be involved in OPDA export from plastids, in Populus trichocarpa. Torr. OPDAT1 is expressed predominantly in young leaves of P. trichocarpa. Functional expression of OPDAT1 in yeast cells revealed that OPDAT1 is involved in OPDA transport. Loss-of-function of OPDAT1 in poplar resulted in increased accumulation of OPDA in the extracted plastids and a reduction in JA concentration, whereas an OPDAT1-overexpressing line showed a reverse tendency in OPDA accumulation and JA biosynthesis. OPDAT1 transcripts were rapidly induced by mechanical wounding of leaves, and an opdat1 mutant transgenic plant displayed increased susceptibility to spider mite (Tetranychus urticae) infestation. Collectively, these data suggest that OPDAT1 is an inner envelope transporter for OPDA, and this has potential implications for JA biosynthesis in poplar under environmental stresses.
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Tyerman, Stephen D., Samantha A. McGaughey, Jiaen Qiu, Andrea J. Yool, and Caitlin S. Byrt. "Adaptable and Multifunctional Ion-Conducting Aquaporins." Annual Review of Plant Biology 72, no. 1 (June 17, 2021): 703–36. http://dx.doi.org/10.1146/annurev-arplant-081720-013608.
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Aquaporins function as water and neutral solute channels, signaling hubs, disease virulence factors, and metabolon components. We consider plant aquaporins that transport ions compared to some animal counterparts. These are candidates for important, as yet unidentified, cation and anion channels in plasma, tonoplast, and symbiotic membranes. For those individual isoforms that transport ions, water, and gases, the permeability spans 12 orders of magnitude. This requires tight regulation of selectivity via protein interactions and posttranslational modifications. A phosphorylation-dependent switch between ion and water permeation in AtPIP2;1 might be explained by coupling between the gates of the four monomer water channels and the central pore of the tetramer. We consider the potential for coupling between ion and water fluxes that could form the basis of an electroosmotic transducer. A grand challenge in understanding the roles of ion transporting aquaporins is their multifunctional modes that are dependent on location, stress, time, and development.
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Lee, Bok-Rye, Rashed Zaman, Van Hien La, Sang-Hyun Park, and Tae-Hwan Kim. "Ethephon-Induced Ethylene Enhances Protein Degradation in Source Leaves, but Its High Endogenous Level Inhibits the Development of Regenerative Organs in Brassica napus." Plants 10, no. 10 (September 23, 2021): 1993. http://dx.doi.org/10.3390/plants10101993.
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To investigate the regulatory role of ethylene in the source-sink relationship for nitrogen remobilization, short-term effects of treatment with different concentrations (0, 25, 50, and 75 ppm) of ethephon (2-chloroethylphosphonic acid, an ethylene inducing agent) for 10 days (EXP 1) and long-term effects at 20 days (Day 30) after treatment with 100 ppm for 10 days (EXP 2) on protein degradation and amino acid transport in foliar sprayed mature leaves of Brassica napus (cv. Mosa) were determined. In EXP 1, endogenous ethylene concentration gradually increased in response to the treated ethephon concentration, leading to the upregulation of senescence-associated gene 12 (SAG12) expression and downregulation of chlorophyll a/b-binding protein (CAB) expression. Further, the increase in ethylene concentration caused a reduction in protein, Rubisco, and amino acid contents in the mature leaves. However, the activity of protease and expression of amino acid transporter (AAP6), an amino acid transport gene, were not significantly affected or slightly suppressed between the treatments with 50 and 75 ppm. In EXP 2, the enhanced ethylene level reduced photosynthetic pigments, leading to an inhibition of flower development without any pod development. A significant increase in protease activity, confirmed using in-gel staining of protease, was also observed in the ethephon-treated mature leaves. Ethephon application enhanced the expression of four amino acid transporter genes (AAP1, AAP2, AAP4, and AAP6) and the phloem loading of amino acids. Significant correlations between ethylene level, induced by ethephon application, and the descriptive parameters of protein degradation and amino acid transport were revealed. These results indicated that an increase in ethylene upregulated nitrogen remobilization in the mature leaves (source), which was accompanied by an increase in proteolytic activity and amino acid transport, but had no benefit to pod (sink) development.
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Hamri, Mohammed Hicham, and Ilham Rharoubi. "Supply Chain Management Control of Fish Canning Industry in Morocco." European Scientific Journal, ESJ 14, no. 10 (April 30, 2018): 332. http://dx.doi.org/10.19044/esj.2018.v14n10p332.
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Management control is increasingly adapted to the changes taking place at inter-firm level of business exchanges. By taking the form of an interorganizational control, the latter aims to reduce uncertainty, avoid opportunism and seek to make the most of an exchange relationship between two organizations. This article analyses some of the main studies dealing with inter-organizational control in the context of supply chain. We present literature review on this type of control, its typology and its approaches and theories. Thanks to its marine biological heritage, Morocco is a world exporter of sea products. The fish preserve sector occupies an important place in the Moroccan economy with a large turnover. This paper presents an exploratory study of this sector where we try to explain the functioning within the canneries of the Souss Massa region in terms of logistic management, the management control function, the management of transport and costs and finally the performance management methods. Based on 12 interviews with managers of canneries in the region, the results of this exploratory study will form the basis on which we will base our main study.
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Hayes Bauer, Eithne, Anders Nikolai Ørsted Schultz, Anette Brink, Lena Oechsle Jørgensen, and Georg Bollig. "Patients’ and Relatives’ Preferences for a Palliative/Oncology Day Ward and Out-of-Hours Telemedicine—An Interpretive Description." Healthcare 9, no. 6 (June 18, 2021): 758. http://dx.doi.org/10.3390/healthcare9060758.
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Demographical challenges require adaptation and tailoring of services to suit palliative patients’ and relatives’ needs. Therefore, an interpretive descriptive study was performed to explore patients’ and relatives’ preferences for the establishment of a day ward and out-of-hours telemedicine. Semi-structured interviews were performed, and data were analysed using thematic analysis. Participants included patients (n = 12) and relatives (n = 5). Three themes emerged: (1) ‘Transport burden’ relates to transition from home-to-hospital-to-home and acknowledges the strain placed on patients and relatives. (2) ‘Role of relatives’ contemplates how the role of families in patient care influences patient preferences. (3) ‘Telemedicine—preferences and concerns’ covers preferences and concerns related to telemedicine in palliative care. The burden of transport and living alone play substantial roles in preferences for place of treatment. Relatives of palliative patients who avail of a day ward and telemedicine may experience an increase in the burden of care. Recognition of concerns pertinent to palliative patients and relatives is an important step in planning new services in palliative care. Concerns may be mitigated by rethinking referral guidelines, incorporating voluntary services, early integration of telemedicine into palliative care and examining patients and relatives’ expectations to care, but requires further research.
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Hawk, C. T., L. H. Kudo, A. J. Rouch, and J. A. Schafer. "Inhibition by epinephrine of AVP- and cAMP-stimulated Na+ and water transport in Dahl rat CCD." American Journal of Physiology-Renal Physiology 265, no. 3 (September 1, 1993): F449—F460. http://dx.doi.org/10.1152/ajprenal.1993.265.3.f449.
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We examined the effects of epinephrine in perfused cortical collecting ducts (CCD) isolated from inbred Dahl-Rapp salt-sensitive (SS) and salt-resistant (SR) rats and from Sprague-Dawley (SD) rats. Rats were treated with 2.5 mg deoxycorticosterone pivalate (DOC; depot injection 4-9 days before study), and the CCD were treated with 220 pM vasopressin (AVP) to maximize Na+ transport. In CCD from all three strains 10 microM epinephrine in the bathing solution completely inhibited net Na+ transport, osmotic water permeability (Pf), and transepithelial voltage. In the SS CCD, epinephrine increased the fractional resistance of the luminal membrane to the same extent as 10 microM amiloride, indicating that it blocked the amiloride-sensitive conductance of the luminal membrane. Even at 100 nM epinephrine inhibited 80-100% of Na+ and water transport, and 1 microM yohimbine reversed or prevented these effects. In SS CCD, 0.1 mM 8-bromoadenosine 3',5'-cyclic monophosphate (8-BrcAMP) plus 0.1 mM 3-isobutyl-1-methylxanthine in place of AVP increased lumen-to-bath Na+ flux (J1-->b) from 56 +/- 5 to 143 +/- 3 pmol.min-1 x mm-1 and Pf from 6 +/- 12 to 1067 +/- 152 microns/s, but 100 mM epinephrine still significantly inhibited cAMP-stimulated J1-->b and Pf by 40 +/- 5% and 31 +/- 9%, respectively. Similar results were observed in the SR and SD rat CCD; however, the ability of yohimbine to reverse the epinephrine effect on cAMP-dependent transport was variable among the rat strains. We conclude that epinephrine acts via an alpha 2-receptor to inhibit adenylate cyclase but that at least one additional intracellular second messenger system may be involved.
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Kincaid, A. E., J. I. Ayers, and J. C. Bartz. "Specificity, Size, and Frequency of Spaces That Characterize the Mechanism of Bulk Transepithelial Transport of Prions in the Nasal Cavities of Hamsters and Mice." Journal of Virology 90, no. 18 (July 6, 2016): 8293–301. http://dx.doi.org/10.1128/jvi.01103-16.
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ABSTRACTInhalation of infected brain homogenate results in transepithelial transport of prions across the nasal mucosa of hamsters, some of which occurs rapidly in relatively large amounts between cells (A. E. Kincaid, K. F. Hudson, M. W. Richey, and J. C. Bartz, J. Virol 86:12731–12740, 2012, doi:http://dx.doi.org/10.1128/JVI.01930-12). Bulk transepithelial transport in the nasal cavity has not been studied to date. In the present study, we characterized the frequency, size, and specificity of the intercellular spaces that mediate the bulk transport of inhaled prions between cells of mice or hamsters following extranasal inoculation with mock-infected brain homogenate, different strains of prion-infected brain homogenate, or brain homogenate mixed with India ink. Infected or mock-infected inoculum was identified within lymphatic vessels of the lamina propria and in spaces of >5 μm between a small number of cells of the nasal mucosa in >90% of animals from 5 to 60 min after inhalation. The width of the spaces between cells, the amount of the inoculum within the lumen of lymphatic vessels, and the timing of the transport indicate that this type of transport was taking place through preexisting spaces in the nasal cavity that were orders of magnitude wider than what is normally reported for paracellular transport. The indiscriminate rapid bulk transport of brain homogenate in the nasal cavity results in immediate entry into nasal cavity lymphatics following inhalation. This novel mechanism may underlie the recent report of the early detection of prions in blood following inhalation and has implications for horizontal prion transmission.IMPORTANCEThe results of these studies demonstrate that the nasal mucosa of mice and hamsters is not an absolute anatomical barrier to inhaled prion-infected or uninfected brain homogenate. Relatively large amounts of infected and uninfected brain homogenate rapidly cross the nasal mucosa and enter the lumen of lymphatic vessels following inhalation. These bulk transepithelial transport events were relatively rare but present in >90% of animals 5 to 60 min following inhalation. This novel mechanism of bulk transepithelial transport was seen in experimental and control hamsters and mice, indicating that it was not species specific or in response to prion exposure. The indiscriminate bulk intercellular transport of inhaled pathogens across the nasal mucosa followed by entry into the lymphatic system may be a mechanism that underlies the entry and spread of other toxins and pathogens in olfactory system-driven animals.
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Schemm, Sebastian, Heini Wernli, and Lukas Papritz. "Warm Conveyor Belts in Idealized Moist Baroclinic Wave Simulations*." Journal of the Atmospheric Sciences 70, no. 2 (February 1, 2013): 627–52. http://dx.doi.org/10.1175/jas-d-12-0147.1.
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Abstract This idealized modeling study of moist baroclinic waves addresses the formation of moist ascending airstreams, so-called warm conveyor belts (WCBs), their characteristics, and their significance for the downstream flow evolution. Baroclinic wave simulations are performed on the f plane, growing from a finite-amplitude upper-level potential vorticity (PV) perturbation on a zonally uniform jet stream. This nonmodal approach allows for dispersive upstream and downstream development and for studying WCBs in the primary cyclone and the downstream cyclone. A saturation adjustment scheme is used as the only difference between the dry and moist simulations, which are systematically compared using a cyclone-tracking algorithm, with an eddy kinetic energy budget analysis, and from a PV perspective. Using trajectories and a selection criterion of maximum ascent, forward- and rearward-sloping WCBs in the moist simulation are identified. No WCB is identified in the dry simulation. Forward-sloping WCBs originate in the warm sector, move into the frontal fracture region, and ascend over the bent-back front, where maximum latent heating occurs in this simulation. The outflow of these WCBs is located at altitudes with prevailing zonal winds; they hence flow anticyclonically (“forward”) into the downstream ridge. In case of a slightly weaker ascent, WCBs curve cyclonically (“rearward”) above the cyclone center. A detailed analysis of the PV evolution along the WCBs reveals PV production in the lower troposphere and destruction in the upper troposphere. Consequently, WCBs transport low-PV air into their outflow region, which contributes to the formation of distinct negative PV anomalies. They, in turn, affect the downstream flow and enhance downstream cyclogenesis.
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Platt, Anthony. "PP11 Relationship between hospital characteristics and survival outcomes in out of hospital cardiac arrest (OHCA) patients treated and transported by yorkshire ambulance service (YAS)." Emergency Medicine Journal 36, no. 10 (September 24, 2019): e6.1-e6. http://dx.doi.org/10.1136/emermed-2019-999abs.11.
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BackgroundThere is mounting evidence that post resuscitation care, should include early angiography and primary percutaneous coronary intervention (PPCI) in OHCA where a cardiac cause is suspected. In Yorkshire, the ambulance service can transport patients with a return of spontaneous circulation (ROSC), directly to a regional PPCI unit, if their ECG shows ST elevation myocardial infarction (STEMI) and the PPCI units accept. The aim of this study was to evaluate transport decisions, hospital characteristics and outcome in the form of 30 day survival rates of post-ROSC patients with presumed cardiac aetiology.MethodsOHCA patient care records (PCRs) between January and July 2017 were reviewed. Patients were eligible for inclusion if they were: an adult non-traumatic OHCA: achieved ROSC on scene, and were transported to hospital. Descriptive statistics were used to analyse the data.Results478 patients met the inclusion criteria. 361/478 (75.6%) patients had an ECG recorded, with 149/361 (41.3%) documented cases of STEMI and 88/149 (59.1%) referred to a PPCI unit. 40/88 (45.5%) of referrals made were accepted by PPCI. Patients taken directly to PPCI were most likely to survive to 30 days (25/39, 53.8%). 34/126 (27.0%) patients survived to 30 days after transport to an emergency department (ED) at a PPCI- capable hospital, and 50/310 (16.1%) survived if taken to ED at a non-PPCI capable hospital.ConclusionWork is required to ensure post-ROSC patients receive a 12 lead ECG, and those with STEMI are referred to PPCI, as survival was greatest in this group. 30 day survival was better for patients taken to ED at a hospital with PPCI facilities, than an ED at a general hospital. Discussion needs to take place between YAS and the relevant hospitals in the region to ensure patients are transported to the appropriate destination.
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Medek, Danielle E., John R. Evans, Marcus Schortemeyer, and Marilyn C. Ball. "Effects of growth temperature on photosynthetic gas exchange characteristics and hydraulic anatomy in leaves of two cold-climate Poa species." Functional Plant Biology 38, no. 1 (2011): 54. http://dx.doi.org/10.1071/fp10023.
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How plastic is hydraulic anatomy with growth temperature, and how does this relate to photosynthesis? These interrelationships were studied in subantarctic Poa foliosa Hook. f. and alpine Poa hothamensis Vickery grown under 7/4°C and 12/9°C day/night temperatures, reflecting summer temperatures in their respective habitats. Conduit radii were smaller in P. foliosa than in P. hothamensis, consistent with greater avoidance of freeze/thaw-induced embolism. Despite its origins in an environment with relatively little temperature variation, P. foliosa exhibited greater plasticity in hydraulic anatomy than P. hothamensis, increasing the size and density of conduits when grown under the warmer temperature regime. Both species had similar anatomical capacities for water transport when grown at 12/9°C, but stomatal conductance was lower in P. foliosa than P. hothamensis, suggesting hydraulic limitations not explained by leaf vascular anatomy. However, greater photosynthetic capacity and foliar nitrogen contents enabled P. foliosa to achieve the same assimilation rate as P. hothamensis under the 12/9°C growth conditions. Our results showed that nitrogen plays a central role in maintaining assimilation rates when constrained either by enzymatic activity at low temperatures or by hydraulic limitations at high temperatures and evaporative demands. Interspecific differences in nitrogen and water use may influence how subantarctic and alpine vegetation responds to climate warming.
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Alcorn, J. L., and C. R. Mendelson. "Trafficking of surfactant protein A in fetal rabbit lung in organ culture." American Journal of Physiology-Lung Cellular and Molecular Physiology 264, no. 1 (January 1, 1993): L27—L35. http://dx.doi.org/10.1152/ajplung.1993.264.1.l27.
Full textAbstract:
Surfactant protein A (SP-A), a major protein component of pulmonary surfactant, is a developmentally and hormonally regulated sialoglycoprotein expressed in type II pneumonocytes. Surfactant proteins and glycerophospholipids are transported to multilamellar structures termed lamellar bodies, which serve to store surfactant lipoprotein until secretion by exocytosis into the alveolar lumen. The cellular mechanism(s) for targeting of SP-A and other surfactant components to lamellar bodies is unknown. In the present study, we have investigated the transport of SP-A to lamellar bodies in fetal rabbit lung tissue in organ culture using pulse-chase analysis of [35S]-methionine-labeled SP-A protein. SP-A accumulated in lamellar bodies within 1–3 h of synthesis; lamellar body SP-A was found to be endoglycosidase H resistant and represented 30–40% of the radiolabeled SP-A recovered from the tissue for periods of up to 12 h postlabeling. Based on our estimates of lamellar body recovery from tissue homogenates, lamellar body-associated SP-A may account for 60–80% of the SP-A present in the fetal lung explants. Treatment of fetal rabbit lung explants with inhibitors of oligosaccharide addition (tunicamycin) and processing (castanospermine), which act within the endoplasmic reticulum, significantly reduced the rate of transport of newly synthesized SP-A to lamellar bodies. An inhibitor of oligosaccharide processing that acts on a processing step that takes place within the Golgi apparatus (swainsonine) reduced the rate of transport of radiolabeled SP-A to lamellar bodies by approximately 50%.(ABSTRACT TRUNCATED AT 250 WORDS)
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Erickson, W. C., L. G. Mundy, and A. Grossman. "High Resolution Imaging at mm-Wavelengths with the Hat Creek Array." Symposium - International Astronomical Union 158 (1994): 349–51. http://dx.doi.org/10.1017/s0074180900107880.
Full textAbstract:
The Hat Creek mm-wavelength array, operated by the Berkeley-Illinois-Maryland Association (BIMA), is undergoing an expansion to nine telescopes. The first six of these telescopes will be operational in January, 1993. The telescopes are relatively small, 6 m in diameter, and are moved on rubber-tired dollies so it will be possible to transport them on roads in the vicinity of the main array. Initially, we plan to place two of the telescopes at outrigger sites located 0.5 and 1.0 km from the main array. Use of these outrigger telescopes will yield angular resolutions of 0.45 arc-sec at 2.7 mm wavelength and 0.21 arc-sec at 1.2 mm wavelength. When all nine telescopes are operational, reasonable image quality will be obtained with a single 12-hour observation. The maximum sidelobe amplitude depends upon source declination, but is about 16%. Figures 1, 2, and 3 show the uv coverage and beamshapes which will be achieved at various declinations.
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Mahamadou, Saley, Issiakou Mahamadou, Abass Saley Abdoulatif, Salaou Nourou, and Garba Zibo. "INTRODUCTION TO THE DEVELOPMENT OF A HYDRAULIC ROAD BINDER BASED ON MINERAL COAL BOTTOM ASH." International Journal of Advanced Research 9, no. 02 (February 28, 2021): 766–72. http://dx.doi.org/10.21474/ijar01/12510.
Full textAbstract:
The use of natural aggregates with suitable characteristics for road construction presents in some regions a real problem of availability or cost related to transport. However, the resources in place, which are naturally unusable, can be used after treatment with Hydraulic Road Binders (HRB). In this study, we propose to valorize the mineral Coal Bottom Ash (CBA), a residue from the combustion of the SONICHAR power station in Niger, as the main component of an HRB.After a physical, chemical and mineralogical characterizationof the coal bottom ash, several proportions of the CBA powder and a cement type CEM I 42.5 were studied. Compression tests were carried out at 07, 28, 56 and 90 days to determine the class of the binder corresponding to the mixture selected.The performance of the HRB thus obtained was evaluated on two types of weakly clay soils (IP <= 12, NF P 94-051), having an initially insufficient CBR. The 3% treatment of this product made the two aforementioned soils suitable for use as a base layer.
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Pasini-Chabot, Ophélie, Julia Vincent, Sylvain Le Pape, Maryne Lepoittevin, Wassim Kaaki, Jean-Baptiste Woillard, Sebastien Giraud, Nicolas Bourmeyster, Thierry Hauet, and Raphael Thuillier. "High Throughput Proteomic Exploration of Hypothermic Preservation Reveals Active Processes within the Cell Associated with Cold Ischemia Kinetic." International Journal of Molecular Sciences 22, no. 5 (February 27, 2021): 2384. http://dx.doi.org/10.3390/ijms22052384.
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The demand for organs to be transplanted increases pressure on procurement centers, to the detriment of organ quality, increasing complications. New preservation protocols are urgently needed, requiring an in-depth understanding of ischemia-reperfusion mechanisms. We performed a proteomic analysis using LC-MS/MS-TOF data analyzed through R software and Cytoscape’s ClueGO application, comparing the proteome of kidney endothelial cells, key cell type, subjected to 3, 6, 12, 19, and 24 h of cold ischemia and 6 h reperfusion. Critical pathways such as energy metabolism, cytoskeleton structure/transport system, and gene transcription/translation were modulated. Important time windows were revealed: a—during the first 3 h, central proteins were upregulated within these pathways; b—the majority of these upregulations were maintained until 12 h cold ischemia time (CIT); c—after that time, the overall decrease in protein expression was observed; d—at reperfusion, proteins expressed in response to cold ischemia were all downregulated. This shows that cold ischemia is not a simple slowing down of metabolism, as deep changes take place within the proteome on major pathways. Time-sensitive expression of key protein reveals possible quality biomarkers as well as potential targets for new strategies to maintain or optimize organ quality.
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Pollet, Nicolas, Roger Cojean, Réjean Couture, Jean-Luc Schneider, Alexander L. Strom, Claire Voirin, and Patrick Wassmer. "A slab-on-slab model for the Flims rockslide (Swiss Alps)." Canadian Geotechnical Journal 42, no. 2 (April 1, 2005): 587–600. http://dx.doi.org/10.1139/t04-122.
Full textAbstract:
The Flims rockslide is the largest landslide in the Alps, with an estimated volume of 12 km3. It resulted from a prehistoric high-speed movement of a large limestone mass. Several main factors influenced the mobility of the Flims rockslide: (i) the steep slopes of the Rhine River valley that blocked the spreading of the rock debris out of the limits of Rabiusa and Carreratobel tributary valleys; (ii) the resisting forces taking place at the base of the rockslide by friction and substratum obstacles; and (iii) the rock mass evolving to a granular state, as observed in the deposits, in which coherence of the original rock massif has been preserved. We expect that most of the energy was consumed by impacting on the opposite slope, forcing the rock mass to stop. Lateral parts and some portions of debris, which entered valleys of the right tributaries of the Rhine River, created tongues by rock avalanche motion, indicating transport velocity. These rock masses eroded the valley fill to create a large mixed mass at the toe of the rockslide deposits. Thus, the Flims rock slope movement can be classified as a rockslide to its middle section and as rock avalanches at its lateral margins. A slab-on-slab model is proposed to characterize transformation of the rock mass during transport, with different stages of motion. Beginning as a rockslide, a delaminating process took place to produce a multislab shearing motion. Shearing and fracturing create dilatancy of the sliding rock debris, with spreading constrained by topographic effects. Dynamic disintegration processes explain the production of fine particles and are at the origin of the granular state of the deposits. Lateral sections of the debris mass continued to flow in the absence of topographic constraints.Key words: rockslide, rock avalanche, Flims, disintegration, topographic control.
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Gilchrist, David G., Richard M. Bostock, and Hong Wang. "Sphingosine-related mycotoxins in plant and animal diseases." Canadian Journal of Botany 73, S1 (December 31, 1995): 459–67. http://dx.doi.org/10.1139/b95-283.
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The AAL-toxins and fumonisins are a group of chemically related phytotoxic congeners produced by Alternaria alternata f. sp. lycopersici and Fusarium moniliforme, respectively, that also are widespread mycotoxins with important health implications. These mycotoxins, which bear a structural relationship to the sphingoid base, sphingosine, also incite maladies in animals ranging from neoplasms to renal, neural, and hepatic necrosis. A. alternata f. sp. lycopersici causes the Alternaria stem canker disease in tomatoes, while F. moniliforme causes pink ear rot of maize and is associated with post-harvest contamination of many different food staples. These toxins are potent inhibitors of ceramide synthase in plants and animals. Sphingoid bases are mediators of signal transduction leading to neoplasms and necrosis in animals. Significant inhibition of ceramide synthase in microsomal preparations of tomato occurs at 20 nM with an I50 in the range of 35–40 nM for both AAL-toxin, TA, and fumonisin, FB1. In plants, specific alterations of physiological processes associated with cellular response to these toxins appears to be required for cell death. A net decrease in sucrose influx to treated leaves occurs within 4 h of AAL-toxin treatment. Untreated leaves of toxin-resistant and -sensitive isolines of tomato show significant differences in sucrose transport capacity. Exogenous application of sucrose transport inhibitors mimicked AAL-toxin symptoms and enhanced cell death in susceptible lines of tomato. Conversely, the accumulation of the ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACQ occurred in 1 h and increased rapidly during the next 6 h after exposure to AAL-toxin. ACC accumulation is followed by a burst in ethylene within 12 h. Application of specific inhibitors of ethylene synthesis or ethylene action results in a decrease in toxin-induced cell death. These toxins appear to be useful tools for defining biochemical and molecular features common to induced cell death in both plants and animals. Key words: AAL-toxins, fumonisins, mycotoxins, host-selective toxins, Alternaria stem canker, Alternaria alternata, Fusarium moniliforme.
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Amit Barman and Saikat Mazumder, Supriti Manna, Dabasmita Saha, Subham Roy Chowdhury. "Onion Productivity and Price Change Aspects in India: An Overview." International Journal for Modern Trends in Science and Technology 6, no. 10 (November 24, 2020): 118–22. http://dx.doi.org/10.46501/ijmtst061021.
Full textAbstract:
AlliumCepathe scientific name of an onion. After potato Onion is the second most essential vegetable in our India. And also onions are very famous in all around the world. In India, the productivity of onion is about 13 lakh tons every month, and in the world, the onion productivity ratio is about 19.40 million. There are about 100 types of onion throughout the world and basically, India produces 9 types of major onion. Onion is very rich in vitamin C (12%)content and vitamin B-6( 5%)content and also rich in minerals like iron(1%) and calcium(2%). In the last 10 years, Maharashtra( 4905.0 thousand tons) is the biggest onion producing state in India. But in 2019 onion prices overlap at Rs 10 kg from Rs 100 kg as demand loss will take place. A huge amount of wastage of onion takes place every year due to bad Monsoon, transport system and the amount of wastage is nearly 25% of the total production. In 10 years a remarkable increase in the production of onion in India and also an increase in the area about 768,000 ha to 1064,000 ha. Onion production has been several benefits like it reduces our cholesterol level, fights against inflammation, decreases triglycerides and it contains a high amount of antioxidants. The impact of onion production on the Indian economy, an increase of onion productivity, price drop, Government policies related to onion production also have been focused on in this review.
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Giertzuch, Peter-Lasse, Joseph Doetsch, Alexis Shakas, Mohammadreza Jalali, Bernard Brixel, and Hansruedi Maurer. "Four-dimensional tracer flow reconstruction in fractured rock through borehole ground-penetrating radar (GPR) monitoring." Solid Earth 12, no. 7 (July 6, 2021): 1497–513. http://dx.doi.org/10.5194/se-12-1497-2021.
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Abstract. Two borehole ground-penetrating radar (GPR) surveys were conducted during saline tracer injection experiments in fully saturated crystalline rock at the Grimsel Test Site in Switzerland. The saline tracer is characterized by an increased electrical conductivity in comparison to formation water. It was injected under steady-state flow conditions into the rock mass that features sub-millimeter fracture apertures. The GPR surveys were designed as time-lapse reflection GPR from separate boreholes and a time-lapse transmission survey between the two boreholes. The local increase in conductivity, introduced by the injected tracer, was captured by GPR in terms of reflectivity increase for the reflection surveys, and attenuation increase for the transmission survey. Data processing and difference imaging was used to extract the tracer signal in the reflection surveys, despite the presence of multiple static reflectors that could shadow the tracer reflection. The transmission survey was analyzed by a difference attenuation inversion scheme, targeting conductivity changes in the tomography plane. By combining the time-lapse difference reflection images, it was possible to reconstruct and visualize the tracer propagation in 3D. This was achieved by calculating the potential radially symmetric tracer reflection locations in each survey and determining their intersections, to delineate the possible tracer locations. Localization ambiguity imposed by the lack of a third borehole for a full triangulation was reduced by including the attenuation tomography results in the analysis. The resulting tracer flow reconstruction was found to be in good agreement with data from conductivity sensors in multiple observation locations in the experiment volume and gave a realistic visualization of the hydrological processes during the tracer experiments. Our methodology was demonstrated to be applicable for monitoring tracer flow and transport and characterizing flow paths related to geothermal reservoirs in crystalline rocks, but it can be transferred in a straightforward manner to other applications, such as radioactive repository monitoring or civil engineering projects.
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Welbourne, T. C., and D. Chevalier. "Glutamate transport and not cellular content modulates paracellular permeability in LLC-PK1-F+ cells." American Journal of Physiology-Endocrinology and Metabolism 272, no. 3 (March 1, 1997): E367—E370. http://dx.doi.org/10.1152/ajpendo.1997.272.3.e367.
Full textAbstract:
Uptake of glutamate modulates two cellular processes: 1) glutamine flux through the cellular glutaminase (GA) and 2) paracellular permeability (PP). Because both responses are the result of a decreased glutamate uptake, the present study was designed to determine whether the transport step or resulting fall in cellular glutamate modulates PP. To do so, advantage was taken of the ability of D-glutamate to competitively displace the natural L-isomer yet maintain transporter activity at or even above that normally occurring with L-glutamate. As a consequence cellular L-glutamate would fall while transporter fluxes remained. Accordingly, LLC-PK1-F+ cells were grown to confluent monolayers on porous supports in Dulbecco's modified Eagle's medium containing 50 microM L-glutamate and 1.8 mM L-glutamine with and without 1 mM D-glutamate. After a 90-min exposure to D-glutamate monolayer, L-glutamate content had fallen 38%. D-Glutamate was transported in place of the L-isomer as evidenced by the accumulation of L-glutamate in the media and uptake of the D-isomer. Although GA activation occurs as the result of the fall in cellular L-glutamate, PP did not increase; in fact, it slightly decreased as evidenced by an increased electrical resistance (from 180 +/- 12 to 210 +/- 10 omega x cm2, P < 0.02) and reduction in L-[(14)C]glucose permeability (2.72 +/- 0.75 to 2.28 +/- 0.37%, P = 0.10). Thus glutamate transporter activity and associated ionic fluxes rather than the fall in cellular glutamate and GA activation appear to play the critical role in modulating PP.
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Macnab, Andrew J., Greg Grant, Kyle Stevens, Faith Gagnon, Robert Noble, and Charles Sun. "Cost: Benefit of Point-of-Care Blood Gas Analysis vs. Laboratory Measurement During Stabilization Prior to Transport." Prehospital and Disaster Medicine 18, no. 1 (March 2003): 24–28. http://dx.doi.org/10.1017/s1049023x00000649.
Full textAbstract:
AbstractIntroduction:This study was conducted to determine whether point-of-care testing, using the iSTAT Portable Clinical Analyzer, would reduce time at the referring hospital required to stabilize ventilated pediatric patients prior to interfacility, air-medical transport.Methods:The following data were collected prospectively: (1) When a blood gas analysis was ordered; (2) If it was necessary to call in a technician; (3) Waiting time for blood to be drawn; and (4) Waiting time for results. The cost-efficacy of point-of-care testing was calculated based on: (1) Three minutes for a transport team member to draw a sample and obtain a result using the iSTAT (unit cost $CDN8,000); (2) Lab technician call-back (minimum two hours at $90); (3) Paramedic overtime (by the minute at $49/hour); and (4) Cost of charter aircraft wait time ($200 per hour) for every hour beyond four hours.Results:Data were collected on 46 ventilated patients over a three month period. A blood gas analysis was ordered on 35 patients. Laboratory technicians were called in for 17 (49%). For 12 (34%) patients, there was a wait for the sample to be drawn, and for 23 (66%), there was a wait for results to become available. Total time waiting to obtain laboratory gases was 526 minutes compared with a calculated 105 minutes using point-of-care testing. An iSTAT cartridge cost of $420 would not have been different from laboratory costs. Cost-saving on technician callback ($1,530), paramedic overtime ($690) and aircraft time waiting charges ($2,000) would have totaled ($4,220). From this study, the cost of point-of-care equipment could be recouped in 101 patients if aircraft charges apply or 192 patients if no aircraft costs are involved. For 11 cases, ventilator adjustments were made subsequently during transport, and for six patients, point-of-care testing, if in place, would have been used to optimize transport care.Conclusion:The data from the present study indicate significant cost-efficacy from use of this technology to reduce stabilization times, and support the potential to improve quality of care during air medical interfacility transport.
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Singh, Devendra Pratap, and Ramani Kumar Sarkar. "Distinction and characterisation of salinity tolerant and sensitive rice cultivars as probed by the chlorophyll fluorescence characteristics and growth parameters." Functional Plant Biology 41, no. 7 (2014): 727. http://dx.doi.org/10.1071/fp13229.
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Soil salinity is a major abiotic stress that limits rice productivity worldwide. The problem is intense – particularly in areas with extremely dry and hot climatic conditions. Designing an effective phenotyping strategy requires thorough understanding of plant survival under stress. The investigation was conducted using 12 rice cultivars differing in salinity tolerance. Among these cultivars, seedling survival on day 10 of salt treatment (12 dS m–1) was above 85% during wet season and 75% during dry season in FL478, AC39416, Pokkali and Kamini. Highly salt-tolerant cultivars maintained greater proportion of green leaf and chlorophyll content under salt stress. Unlike sensitive cultivars, tolerant cultivars taken up less Na+ and more K+, resulting in lower Na+ : K+ ratio in leaf and sheath. Normalised chlorophyll a fluorescence data revealed that the Fv/Fm and PIABS values decreased on days 3 and 7, respectively, of salt stress in susceptible rice cultivar. Salinity factor index (SFI) calculated by giving different weights to relative PIABS values after variable days of salinity stress clearly distinguished the level of tolerance among rice cultivars. The SFI can be used for grouping of moderately to highly salt-tolerant cultivars based on their tolerance level. We conclude that maintenance of greater proportion of green leaf, and restricted transport of Na+ to sheath and leaf helps the plant to counteract adverse effects of salinity on rice growth.
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Norman, D. J., and J. O. Strandberg. "Survival of Colletotrichum acutatum in Soil and Plant Debris of Leatherleaf Fern." Plant Disease 81, no. 10 (October 1997): 1177–80. http://dx.doi.org/10.1094/pdis.1997.81.10.1177.
Full textAbstract:
Leatherleaf fern anthracnose is incited by a new pathotype of Colletotrichum acutatum. Fern anthracnose appeared in Florida in 1993, has spread rapidly, and produces losses that approach 100% in some ferneries. To help develop recommendations for control and management of fern anthracnose, the survival of the pathogen in soil and diseased plant material and on clothing was investigated in laboratory and field experiments. Survival of conidia, sclerotia, and conidia in infected leaf debris was studied in soil maintained at five soil moisture levels. Survival of conidia and sclerotia declined rapidly under moist conditions (≥12% moisture, vol/wt), but under dry conditions, viable conidia could be detected up to 12 months after incorporation into soil. Similar results were obtained in field experiments in which infected leaf debris was buried in soil. Viable conidia were recovered for up to 3 months in leaf debris stored under laboratory conditions. Conidia applied to denim fabric were recovered up to 5 weeks after application. This indicated that contaminated clothing could transport conidia effectively within and between ferneries. Inoculating ferns with dilutions of conidia demonstrated that at least 100 conidia per ml is required to infect and colonize leatherleaf fern leaves. This threshold provides an estimate of levels of conidia populations likely to result in disease and levels that sanitation or cultural practices must exceed to be effective management methods.
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Vamza, Ilze, Karlis Valters, Arnis Dzalbs, Edgars Kudurs, and Dagnija Blumberga. "Criteria for Choosing Thermal Packaging for Temperature Sensitive Goods Transportation." Environmental and Climate Technologies 25, no. 1 (January 1, 2021): 382–91. http://dx.doi.org/10.2478/rtuect-2021-0028.
Full textAbstract:
Abstract Today cold chain transportation has become more important than before, as countries rely on cold chain logistics to store and transport SARS-CoV-2 vaccines and other temperature-sensitive goods. The cold chain is usually associated with the use of non-renewable materials and higher energy consumption than the regular supply chain. An important part of cold chain sustainability is thermal packaging. Up to now one of the most popular thermal packaging materials is polystyrene – made from fossil raw material. Polystyrene has low thermal conductivity and density, but it breaks down into micro- and nano plastics when exposed to sunlight making it environmentally unsustainable. To determine which factors are important for cold chain regarding thermal packaging, 12 criteria were compared to determine their ranking. Further multi-criteria analysis was used to compare polystyrene to four alternative biodegradable thermal packaging options: mycelium-based, corn starch, non-woven wool, and non-woven feathers. Polystyrene gained only 3rd place with a 0.70 proximity to ideal solution 1, but non-woven wool showed the best result with 0.88 proximity to ideal solution.
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Лось, Александр Васильевич, Владимир Федорович Шмырев, and Виктор Иванович Рябков. "ДОСТИЖЕНИЕ ПРЕИМУЩЕСТВА Ан-188 СРЕДИ ОПЕРАТИВНО–ТАКТИЧЕСКИХ ВОЕННО-ТРАНСПОРТНЫХ САМОЛЕТОВ." Aerospace technic and technology, no. 8 (August 31, 2020): 5–11. http://dx.doi.org/10.32620/aktt.2020.8.01.
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In the "Antonov" Company, a unique medium-sized tactical military transport aircraft An-12 and An-70 have been created. Based on the Аn-12 basic version, several modifications have been developed, which operate in many countries around the world.To replace this aircraft has been created the An-70 with a higher capacity and hourly capacity, which on some key parameters outperforms the competition-analogs: American C-130J-30, West-European A400M, and Japanese C-2.However, the range with the maximum capacity is worse for Аn-77 compared to the A400M, but cruising speed and combat readiness – for C-2.For the most complete implementation of tactical tasks:– transportation of personnel, equipment, goods, and means of procurement;– delivery of military units, equipment, and cargo in the interests of peacekeeping or counter-terrorism operations;– transportation of troops, arms, military equipment and material resources of strategic direction;– delivery of units and formations of the airborne forces and ground forces in the areas of military purpose;– provision of the relocation of aviation units and formations, and provision of superiority at range with maximum load, at cruising speed and combat readiness the team of the “Antonov” Company created the An-188 – the medium-sized tactical aircraft with short takeoff and landing, which provides execution of a series of tasks, not available even for C-2.At the initial stage of designing this modification scientific principles the "Design techniques of modifications of the MTA taking into account the profound changes in the wing and the power plant" were used. The most important modification change in An-188 is the replacement of the D-27 turboprop engine for СFM LЕАР-1A turbofan engine, which increased the capacity and combat readiness of modification.Another important modification change was the use of discrete geometric twist of the wing local chord, bringing its shape in plan view to elliptical one and has brought a reduction in induced drag for a given lift force. This solution provided an increase in the range of up to 3200 km.Such profound modification changes in the power plant and the geometry of the wing have contributed to the complete superiority of the An-188 in the class of operational-tactical MTA.In combination with An-132D and An-178 modification, the An-188 can be considered as a unified system of support for the troops with military transport planes.
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Bubier, J., A. Costello, T. R. Moore, N. T. Roulet, and K. Savage. "Microtopography and methane flux in boreal peatlands, northern Ontario, Canada." Canadian Journal of Botany 71, no. 8 (August 1, 1993): 1056–63. http://dx.doi.org/10.1139/b93-122.
Full textAbstract:
Fluxes of methane were measured by a static chamber technique at hummock, hollow, and lawn microtopographic locations in 12 peatland sites near Cochrane, northern Ontario, from May to October 1991. Average fluxes (mg∙m−2∙d−1) were 2.3 (SD = 1.9) at hummocks, 44.4 (SD = 49.0) at hollows, and 15.6 (SD = 12.9) at lawns. Methane flux was negatively correlated with average water table position based on the 36 locations (r2 = 0.649, p < 0.001), with hummocks having a smaller flux than hollows or lawns, where the water table depth was < 25 cm. Peat samples from a bog hummock and hollow failed to produce methane during anaerobic incubations in the laboratory; samples from a poor fen hollow produced < 1.4 μg∙g−1∙d−1. The production decreased with depth but was greater than the rates observed during the incubation of samples from an adjacent hummock. Rates of methane consumption during aerobic incubations ranged from 1 to 55 μg∙g−1∙d−1 and were greatest in the surface layers and decreased with depth. Differences in methane emissions between hummocks and hollows appear to be controlled primarily by greater methane production rates in hollows compared with hummocks. Of secondary importance are the capacity of the peat profiles to consume methane during its transport to the peat surface and warmer temperatures at the water table beneath hollows compared with hummocks. Key words: peatlands, methane, bog, fen, decomposition.
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Heiland, Sylvia, Nada Radovanovic, Milan Höfer, Joris Winderickx, and Hella Lichtenberg. "Multiple Hexose Transporters ofSchizosaccharomyces pombe." Journal of Bacteriology 182, no. 8 (April 15, 2000): 2153–62. http://dx.doi.org/10.1128/jb.182.8.2153-2162.2000.
Full textAbstract:
ABSTRACT We have identified a family of six hexose transporter genes (Ght1 to Ght6) in the fission yeastSchizosaccharomyces pombe. Sequence homology toSaccharomyces cerevisiae and mammalian hexose transporters (Hxtp and GLUTp, respectively) and secondary-structure predictions of 12 transmembrane domains for each of the Ght proteins place them into the sugar porter subfamily within the major facilitator superfamily. Interestingly, among this sugar porter family, the emerging S. pombe hexose transporter family clusters are separate from monosaccharide transporters of other yeasts (S. cerevisiae,Kluyveromyces lactis, and Candida albicans) and of humans, suggesting that these proteins form a distinct structural family of hexose transporters. Expression of the Ght1,Ght2, Ght5, and Ght6 genes in theS. cerevisiae mutant RE700A may functionally complement itsd-glucose uptake-deficient phenotype. Northern blot analysis and reverse transcription-PCR showed that among allGht's of S. pombe, Ght5 is the most prominently expressed hexose transporter. Ght1p, Ght2p, and Ght5p displayed significantly higher specificities for d-glucose than for d-fructose. Analysis of the previously describedS. pombe d-glucose transport-deficient mutant YGS-5 revealed that this strain is defective in the Ght1,Ght5, and Ght6 genes. Based on an analysis of three S. pombe strains bearing single or double mutations in Ght3 and Ght4, we conclude that the Ght3p function is required for d-gluconate transport in S. pombe. The function of Ght4p remains to be clarified. Ght6p exhibited a slightly higher affinity to d-fructose than tod-glucose, and among the Ght's it is the transporter with the highest specificity for d-fructose.
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Arzel, Olivier, and Alain Colin de Verdière. "Can We Infer Diapycnal Mixing Rates from the World Ocean Temperature–Salinity Distribution?" Journal of Physical Oceanography 46, no. 12 (December 2016): 3751–75. http://dx.doi.org/10.1175/jpo-d-16-0152.1.
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AbstractThe turbulent diapycnal mixing in the ocean is currently obtained from microstructure and finestructure measurements, dye experiments, and inverse models. This study presents a new method that infers the diapycnal mixing from low-resolution numerical calculations of the World Ocean whose temperatures and salinities are restored to the climatology. At the difference of robust general circulation ocean models, diapycnal diffusion is not prescribed but inferred. At steady state the buoyancy equation shows an equilibrium between the large-scale diapycnal advection and the restoring terms that take the place of the divergence of eddy buoyancy fluxes. The geography of the diapycnal flow reveals a strong regional variability of water mass transformations. Positive values of the diapycnal flow indicate an erosion of a deep-water mass and negative values indicate a creation. When the diapycnal flow is upward, a diffusion law can be fitted in the vertical and the diapycnal eddy diffusivity is obtained throughout the water column. The basin averages of diapycnal diffusivities are small in the first 1500 m [O(10−5) m2 s−1] and increase downward with bottom values of about 2.5 × 10−4 m2 s−1 in all ocean basins, with the exception of the Southern Ocean (50°–30°S), where they reach 12 × 10−4 m2 s−1. This study confirms the small diffusivity in the thermocline and the robustness of the higher canonical Munk’s value in the abyssal ocean. It indicates that the upward dianeutral transport in the Atlantic mostly takes place in the abyss and the upper ocean, supporting the quasi-adiabatic character of the middepth overturning.
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Garrett, Ryan W., Katherine A. Carlson, Matthew Scott Goggans, Michael H. Nesson, Christopher A. Shepard, and Robert M. S. Schofield. "Leaf processing behaviour in Atta leafcutter ants: 90% of leaf cutting takes place inside the nest, and ants select pieces that require less cutting." Royal Society Open Science 3, no. 1 (January 2016): 150111. http://dx.doi.org/10.1098/rsos.150111.
Full textAbstract:
Leafcutter ants cut trimmings from plants, carry them to their underground nests and cut them into smaller pieces before inoculating them with a fungus that serves as a primary food source for the colony. Cutting is energetically costly, so the amount of cutting is important in understanding foraging energetics. Estimates of the cutting density, metres of cutting per square metre of leaf, were made from samples of transported leaf cuttings and of fungal substrate from field colonies of Atta cephalotes and Atta colombica . To investigate cutting inside the nest, we made leaf-processing observations of our laboratory colony, A. cephalotes . We did not observe the commonly reported reduction of the leaf fragments into a pulp, which would greatly increase the energy cost of processing. Video clips of processing behaviours, including behaviours that have not previously been described, are linked. An estimated 2.9 (±0.3) km of cutting with mandibles was required to reduce a square metre of leaf to fungal substrate. Only about 12% (±1%) of this cutting took place outside of the nest. The cutting density and energy cost is lower for leaf material with higher ratios of perimeter to area, so we tested for, and found that the laboratory ants had a preference for leaves that were pre-cut into smaller pieces. Estimates suggest that the energy required to transport and cut up the leaf material is comparable to the metabolic energy available from the fungus grown on the leaves, and so conservation of energy is likely to be a particularly strong selective pressure for leafcutter ants.