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11.
Summary Rational method of improving poor water by the admixture of good-quality water for irrigation purposes is proposed and demonstrated. The principles of the dilution process, carried out in dilution junctions, are explained. Continuity equations for water and for the mass of relevant substances present in the water are derived for a dilution junction. These equations characterize the suitability of the mixture for irrigation. The optimal operation of a dilution network for irrigation with brackish, sewage and fresh water is formulated and analyzed based on graph theory. A system of non-linear constraints which satisfactorily describes requirements for water quality and flow rates in terms of field demands and water sources is presented. Optimal operation is defined as the minimum water delivery cost. In dilution networks having no more than one outflow conduit of unknown concentration per junction, the non-linear optimization problem can be reduced into a linear one, making the use of Linear Programming (LP) possible.Adapting the proposed dilution network concept to irrigation can provide a practical means for controlling the quality of water applied in the field. 相似文献
12.
Dan G. Ohad DVM PhD Yitzhak Sinai DVM Asaph Zaretsky DVM Rona Shofti DVM PhD 《Journal of Veterinary Cardiology》2008,10(2):147-154
A 4-year-old, intact male Dogue de Bordeaux dog with congenital valvular pulmonic stenosis, tricuspid valve dysplasia, and chronic atrial fibrillation underwent ultrasound-guided balloon valvuloplasty in addition to pharmacological treatment. Owner compliance to prescribed pharmacotherapy proved very poor, and concerns developed regarding the ability to successfully control heart rate and symptoms using drug therapy alone. These concerns were addressed by the implantation of a novel vagal stimulation system that was programmed to prevent a ventricular rate of >145 bpm. Consequently, post-operative ventricular response rate decreased from up to 250 to 140 bpm. Successful ventricular rate control was maintained for 291 days post-operatively, following which euthanasia was elected by the owner due to persistent right-sided congestive heart failure. To the authors' knowledge, this is the first report of successful continuous rate control using a vagal stimulating system in a closed-chest, client-owned dog with chronic atrial fibrillation secondary to spontaneously occurring organic heart disease. 相似文献
13.
M. Wysoki G. Forer E. Dunkelblum Miriam Harel Polina Fraistat Devora Gordon L. Anshelevich M. Kehat M. Kehat L. Anshelevich Devora Gordon Miriam Harel E. Dunkelblum L. Zilberg A. Rubin A. Shani Ada Rafaeli Miriam Altstein Oma Ben-Aziz Irit Schafler I. Seltzer C. Gilon A. Hefetz Tamar Katzav Victoria Soroker Ali R. Harari 《Phytoparasitica》1998,26(2):175-181
14.
Eden E Geva-Zatorsky N Issaeva I Cohen A Dekel E Danon T Cohen L Mayo A Alon U 《Science (New York, N.Y.)》2011,331(6018):764-768
Cells remove proteins by two processes: degradation and dilution due to cell growth. The balance between these basic processes is poorly understood. We addressed this by developing an accurate and noninvasive method for measuring protein half-lives, called "bleach-chase," that is applicable to fluorescently tagged proteins. Assaying 100 proteins in living human cancer cells showed half-lives that ranged between 45 minutes and 22.5 hours. A variety of stresses that stop cell division showed the same general effect: Long-lived proteins became longer-lived, whereas short-lived proteins remained largely unaffected. This effect is due to the relative strengths of degradation and dilution and suggests a mechanism for differential killing of rapidly growing cells by growth-arresting drugs. This approach opens a way to understand proteome half-life dynamics in living cells. 相似文献
15.
The effect of lead on photosynthetic light storage efficiency was measured by the photoacoustic method. The advantage of this method is in its directness, since the signal obtained by a hydrophone is proportional to that fraction of light energy that is dissipated as heat. This increases as less energy is stored photochemically if the photosynthetic apparatus is damaged. Cells of shape Synechococcus leopoliensis (Cyanobacteria) were grown in medium containing lead in concentrations of 0, 25, 50, 100, and 200 ppm. To avoid the co-precipitation of lead and phosphorus as lead phosphate, phosphorus was omitted from the media used during weeklong exposure to lead. Both chlorophyll concentration and photosynthetic energy storage efficiency decreased with time and with lead concentration. Reduction of photosynthesis progressed with time and increased with lead concentration, reaching up to 80% at the highest lead concentration after seven days. 相似文献
16.
Summary The utility of a saline water source for irrigation might, in many cases, be greatly increased if it could be diluted by mixing it with a higher quality source of water prior to field application. This paper discusses a number of options for achieving such a dilution subject to imposed constraints. Firstly, we derive and discuss the principles of achieving control of irrigation salinity level when waters of two different qualities and flow rates are used. Secondly, we formulate and discuss the dynamic performance of a prototype on a controlled dilution junction with and without water storage. Finally, we discuss the general problem of achieving simultaneous salinity and flow rate control, using dual feedback control sensors to compensate for variations both in salinity and in flow rate of the saline supply source in order to produce a desired salt concentration in the irrigation water. 相似文献
17.
Does mating disruption of Planococcus ficus and Lobesia botrana affect the diversity,abundance and composition of natural enemies in Israeli vineyards? 
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Dugladze T Schmitz D Whittington MA Vida I Gloveli T 《Science (New York, N.Y.)》2012,336(6087):1458-1461
In central neurons, information flows from the dendritic surface toward the axon terminals. We found that during in vitro gamma oscillations, ectopic action potentials are generated at high frequency in the distal axon of pyramidal cells (PCs) but do not invade the soma. At the same time, axo-axonic cells (AACs) discharged at a high rate and tonically inhibited the axon initial segment, which can be instrumental in preventing ectopic action potential back-propagation. We found that activation of a single AAC substantially lowered soma invasion by antidromic action potential in postsynaptic PCs. In contrast, activation of soma-inhibiting basket cells had no significant impact. These results demonstrate that AACs can separate axonal from somatic activity and maintain the functional polarization of cortical PCs during network oscillations. 相似文献
19.
Cotton root growth as affected by changes in soil water distribution and their impact on plant tolerance to drought 总被引：1，自引：0，他引：1
The capability of mature cotton plants (Gossypium hirsutum L.) to adjust to progressive drying of their root zone by promoting root growth to adjacent wetted zones, and the implications of this process on irrigation design were investigated. Field grown plants that developed shallow root systems in response to a drip irrigation management of daily, surface soil wettings were exposed 85 days after emergence (DAE), while in the flowering stage, to a sudden change in water distribution in the form of deep soil wetting (DSW) followed by termination of irrigation. The shallow rooted plants (SRP) failed to respond to further surface soil wetting and the progressive drying of the profile by rapid root growth to the deeper-wetted zones; consequently, the SRP suffered from water deficiency for at least two weeks, evidenced by a gradual decrease in their leaf water potential (Lw). Potted plants responded similarly. Daily irrigations of the pot surface with water amounts similar to those lost by evapotranspiration led to the development of a system in which most of the roots and available water became concentrated at the pot's upper section. A transition to irrigation from the bottom of the pot led to a reversed soil-water content gradient and failed to promote rapid root spreading to the deeper-wetted layers, in spite of the accelerated drying of the upper zone. The slow deepening of the root system was accompanied by water-stress symptoms as indicated by a considerable reduction in dry matter production. The root shoot ratio in these plants was not much greater than in non-stressed plants in which the surface wetting was continued. This indicated that preferential root growth relative to the shoot did not occur in response to the progressive drying of the shallow root zone. Rewetting of the root zone after a long period of soil water deficiency failed to promote rapid recovery of the root system in the form of root regrowth in this zone. It was concluded that the capability of mature cotton plant roots to adjust their growth to large changes in water distribution in the soil, is slow and that this should be taken into account when determining an irrigation regime in which the depth at which water is applied is changed during the growing season.Contribution from the Agricultural Research Organization, Volcani Center, Bet Dagan, Israel; No. 343-E, 1992 series 相似文献
20.
Smith FA Boyer AG Brown JH Costa DP Dayan T Ernest SK Evans AR Fortelius M Gittleman JL Hamilton MJ Harding LE Lintulaakso K Lyons SK McCain C Okie JG Saarinen JJ Sibly RM Stephens PR Theodor J Uhen MD 《Science (New York, N.Y.)》2010,330(6008):1216-1219
The extinction of dinosaurs at the Cretaceous/Paleogene (K/Pg) boundary was the seminal event that opened the door for the subsequent diversification of terrestrial mammals. Our compilation of maximum body size at the ordinal level by sub-epoch shows a near-exponential increase after the K/Pg. On each continent, the maximum size of mammals leveled off after 40 million years ago and thereafter remained approximately constant. There was remarkable congruence in the rate, trajectory, and upper limit across continents, orders, and trophic guilds, despite differences in geological and climatic history, turnover of lineages, and ecological variation. Our analysis suggests that although the primary driver for the evolution of giant mammals was diversification to fill ecological niches, environmental temperature and land area may have ultimately constrained the maximum size achieved. 相似文献