The Experts below are selected from a list of 24264 Experts worldwide ranked by ideXlab platform
Nathaniel M Fried - One of the best experts on this subject based on the ideXlab platform.
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Thulium fiber laser lithotripsy using tapered fibers.
Lasers in surgery and medicine, 2010Co-Authors: Richard L. Blackmon, Pierce B. Irby, Nathaniel M FriedAbstract:Introduction The Thulium fiber laser has recently been tested as a potential alternative to the Holmium:YAG laser for lithotripsy. This study explores use of a short taper for expanding the Thulium fiber laser beam at the distal tip of a small-core fiber. Methods Thulium fiber laser radiation with a wavelength of 1,908 nm, 10 Hz pulse rate, 70 mJ pulse energy, and 1-millisecond pulse duration was delivered through a 2-m-length fiber with 150-µm-core-input-end, 300-µm-core-output-end, and 5-mm-length taper, in contact with human uric acid (UA) and calcium oxalate monohydrate (COM) stones, ex vivo (n = 10 each). Stone mass loss, stone crater depths, fiber transmission losses, fiber burn-back, Irrigation Rates, and deflection through a flexible ureteroscope were measured for the tapered fiber and compared with conventional fibers. Results After delivery of 1,800 pulses through the tapered fiber, mass loss measured 12.7±2.6 mg for UA and 7.2±0.8 mg COM stones, comparable to conventional 100-µm-core fibers (12.6±2.5 mg for UA and 6.8±1.7 mg for COM stones). No transmission losses or burn-back occurred for the tapered fiber after 36,000 pulses, while a conventional 150-µm fiber experienced significant tip degradation after only 1,800 pulses. High Irrigation Rates were measured with the tapered fiber inserted through the working port of a flexible ureteroscope without hindering its deflection, mimicking that of a conventional 150 µm fiber. Conclusions The short tapered distal fiber tip allows expansion of the laser beam, resulting in decreased fiber tip damage compared to conventional small-core fibers, without compromising fiber bending, stone vaporization efficiency, or Irrigation Rates. Lasers Surg. Med. 42:45–50, 2010. © 2010 Wiley-Liss, Inc.
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thulium fiber laser ablation of urinary stones through small core optical fibers
IEEE Journal of Selected Topics in Quantum Electronics, 2009Co-Authors: Nicholas J Scott, Christopher M Cilip, Nathaniel M FriedAbstract:Complications during laser lithotripsy include optical fiber bending failure resulting in endoscope damage and low Irrigation Rates leading to poor visibility. Both problems are related to fiber diameter and limited by the holmium:YAG (Ho:YAG) laser (lambda = 2120 nm) multimode beam profile. This study exploits the thulium fiber laser (lambda = 1908 nm) beam profile for higher power transmission through smaller fibers. Thulium fiber laser radiation with 1 ms pulse duration, pulse Rates of 10-30 Hz, and 70-mu m-diameter spot was coupled into silica fibers with 100, 150, and 200 mum core diameters. Fiber transmission, bending, and endoscope Irrigation tests were performed. Damage thresholds for 100, 150, and 200 mum fibers averaged 40, 60, and > 80 W, respectively. Irrigation Rates measured 35, 26, and 15 mL/min for no fiber, and 100 and 200 mum fibers. Thulium fiber laser energy of 70 mJ delivered at 20 Hz through a 100 mum fiber resulted in vaporization and fragmentation Rates of 10 and 60 mg/min for uric acid stones. The thulium fiber laser beam profile provides higher laser power through smaller fibers than Ho:YAG laser, potentially reducing fiber failure and endoscope damage, and allowing greater Irrigation Rates for improved visibility.
Urs Schmidhalter - One of the best experts on this subject based on the ideXlab platform.
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Combining biophysical parameters, spectral indices and multivariate hyperspectral models for estimating yield and water productivity of spring wheat across different agronomic practices
2019Co-Authors: Salah El-hendawy, Nasser Al-suhaibani, Salah Elsayed, Yahya Refay, Majed Alotaibi, Yaser Hassan Dewir, Wael Hassan, Urs SchmidhalterAbstract:Manipulating plant densities under different Irrigation Rates can have a significant impact on grain yield and water use efficiency by exerting positive or negative effects on ET. Whereas traditional spectral reflectance indices (SRIs) have been used to assess biophysical parameters and yield, the potential of multivariate models has little been investigated to estimate these parameters under multiple agronomic practices. Therefore, both simple indices and multivariate models (partial least square regression (PLSR) and support vector machines (SVR)) obtained from hyperspectral reflectance data were compared for their applicability for assessing the biophysical parameters in a field experiment involving different combinations of three Irrigation Rates (1.00, 0.75, and 0.50 ET) and five plant densities (D1: 150, D2: 250, D3: 350, D4: 450, and D5: 550 seeds m-2) in order to improve productivity and water use efficiency of wheat. Results show that the highest values for green leaf area, aboveground biomass, and grain yield were obtained from the combination of D3 or D4 with 1.00 ET, while the combination of 0.75 ET and D3 was the best treatment for achieving the highest values for water use efficiency. Wheat yield response factor (ky) was acceptable when the 0.75 ET was combined with D2, D3, or D4 or when the 0.50 ET was combined with D2 or D3, as the ky values of these combinations were less than or around one. The production function indicated that about 75% grain yield variation could be attributed to the variation in seasonal ET. Results also show that the performance of the SRIs fluctuated when regressions were analyzed for each Irrigation rate or plant density specifically, or when the data of all Irrigation Rates or plant densities were combined. Most of the SRIs failed to assess biophysical parameters under specific Irrigation Rates and some specific plant densities, but performance improved substantially for combined data of Irrigation Rates and some specific plant densities. PLSR and SVR produced more accurate estimations of biophysical parameters than SRIs under specific Irrigation Rates and plant densities. In conclusion, hyperspectral data are useful for predicting and monitoring yield and water productivity of spring wheat across multiple agronomic practices.
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Hyperspectral reflectance sensing to assess the growth and photosynthetic properties of wheat cultivars exposed to different Irrigation Rates in an irrigated arid region.
PloS one, 2017Co-Authors: Salah El-hendawy, Nasser Al-suhaibani, Wael M. Hassan, Mohammad Tahir, Urs SchmidhalterAbstract:Simultaneous indirect assessment of multiple and diverse plant parameters in an exact and expeditious manner is becoming imperative in irrigated arid regions, with a view toward creating drought-tolerant genotypes or for the management of precision Irrigation. This study aimed to evaluate whether spectral reflectance indices (SRIs) in three parts of the electromagnetic spectrum ((visible-infrared (VIS), near-infrared (NIR)), and shortwave-infrared (SWIR)) could be used to track changes in morphophysiological parameters of wheat cultivars exposed to 1.00, 0.75, and 0.50 of the estimated evapotranspiration (ETc). Significant differences were found in the parameters of growth and photosynthetic efficiency, and canopy spectral reflectance among the three cultivars subjected to different Irrigation Rates. All parameters were highly and significantly correlated with each other particularly under the 0.50 ETc treatment. The VIS/VIS- and NIR/VIS-based indices were sufficient and suitable for assessing the growth and photosynthetic properties of wheat cultivars similar to those indices based on NIR/NIR, SWIR/NIR, or SWIR/SWIR. Almost all tested SRIs proved to assess growth and photosynthetic parameters, including transpiration rate, more efficiently when regressions were analyzed for each water Irrigation rate individually. This study, the type of which has rarely been conducted in irrigated arid regions, indicates that spectral reflectance data can be used as a rapid and non-destructive alternative method for assessment of the growth and photosynthetic efficiency of wheat under a range of water Irrigation Rates.
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optimal coupling combinations between the Irrigation rate and glycinebetaine levels for improving yield and water use efficiency of drip irrigated maize grown under arid conditions
Agricultural Water Management, 2014Co-Authors: Maher A Kotab, Salah Elhendawy, Nasser Alsuhaibani, Urs SchmidhalterAbstract:Abstract This study was conducted over 2 years (2011 and 2012) to determine the optimal combinations between the Irrigation rate and glycinebetaine (GB) levels in order to maximise yield and Irrigation water use efficiency (IWUE) for drip-irrigated maize. A field experiment was performed using a randomised complete block split plot design with three drip Irrigation Rates ( I 1 : 1.00, I 2 : 0.80, and I 3 : 0.60 of the estimated evapotranspiration, ET) and five GB levels (GB 0 , GB 25 , GB 50 , GB 75 and GB 100 , GB levels at 0, 25, 50, 75 and 100 mM, respectively) as the main and split plots, respectively. We found that although exogenously applied GB appeared to have different effects on yield variables and IWUE, these differences were dependent on the level of GB within the same Irrigation rate. The grain yield and yield component values for I 2 GB 50 treatment were occasionally comparable to those obtained for I 1 GB 0 treatment, and the values for both treatments were higher than those obtained for I 1 GB 75 or I 1 GB 100 . I 3 GB 50 or I 3 GB 100 had grain yield and yield component values similar to those obtained for I 2 GB 0 and I 2 GB 100 . The highest value for IWUE was found for I 2 GB 50 and this value was similar to that obtained with I 3 GB 75 , while the lowest values were obtained for I 1 GB 75 or I 1 GB 100 . Medium GB levels were effective under I 2 and I 3 treatments to obtain the lowest value for seasonal yield response factors ( k y ). The production functions of yield versus GB levels were second-order relationship for all drip Irrigation Rates. In conclusion, exogenous application of GB has the potential to improve yield and IWUE under limited water application, while a threshold level of GB was required for a positive effect.
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Irrigation rate and plant density effects on yield and water use efficiency of drip irrigated corn
Agricultural Water Management, 2008Co-Authors: Salah Elhendawy, Essam Abd A Ellattief, Mohamed S Ahmed, Urs SchmidhalterAbstract:The efficient use of water by modern Irrigation systems is becoming increasingly important in arid and semi-arid regions with limited water resources. This study was conducted for 2 years (2005 and 2006) to establish optimal Irrigation Rates and plant population densities for corn (Zea mays L.) in sandy soils using drip Irrigation system. The study aimed at achieving high yield and efficient Irrigation water use (IWUE) simultaneously. A field experiment was conducted using a randomized complete block split plot design with three drip Irrigation Rates (I1: 1.00, I2: 0.80, and I3: 0.60 of the estimated evapotranspiration), and three plant population densities (D1: 48,000, D2: 71,000 and D3: 95,000 plants ha-1) as the main plot and split plot, respectively. Irrigation water applied at I1, I2 and I3 were 5955, 4762 and 3572 m3 ha-1, respectively. A 3-day Irrigation interval and three-way cross 310 hybrid corn were used. Results indicated that corn yield, yield components, and IWUE increased with increasing Irrigation Rates and decreasing plant population densities. Significant interaction effects between Irrigation rate and plant population density were detected in both seasons for yield, selected yield components, and IWUE. The highest grain yield, yield components, and IWUE were found for I1D1, I1D2, or I2D1, while the lowest were found for I3D2 or I3D3. Thus, a high Irrigation rate with low or medium plant population densities or a medium Irrigation rate with a low plant population density are recommended for drip-irrigated corn in sandy soil. Crop production functions with respect to Irrigation Rates, determined for grain yield and different yield components, enable the results from this study to be extrapolated to similar agro-climatic conditions
John C Cushman - One of the best experts on this subject based on the ideXlab platform.
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biomass production nutritional and mineral content of desiccation sensitive and desiccation tolerant species of sporobolus under multiple Irrigation regimes
Journal of Agronomy and Crop Science, 2013Co-Authors: Abou Yobi, Barry L Perryman, Karen Schlauch, Melvin J Oliver, John C CushmanAbstract:The development of low-water-input forages would be useful for improving the water-use efficiency of livestock production in semi-arid and arid regions. The desiccation-tolerant (DT) species Sporobolus stapfianus Gandoger and two desiccation-sensitive (DS) species, Sporobolus pyramidalis and Sporobolus fimbriatus (Trin.) Nees. (Poaceae), were evaluated for aerial biomass production and seed productivity under three different Irrigation regimes. Sporobolus stapfianus displayed the least biomass production, whereas S. pyramidalis and S. fimbriatus produced up to 3.8and 11.2-fold greater dry biomass, respectively, at the highest Irrigation rate of 12 334 l (0.01 acre-feet). Sporobolus fimbriatus and to a lesser extent S. pyramidalis showed significant increases in biomass production in response to increased Irrigation Rates, whereas S. stapfianus did not. Sporobolus pyramidalis and S. fimbriatus exhibited 3.2and 6.0-fold greater seed production, respectively, in response to increased Irrigation Rates, whereas S. stapfianus showed only a 1.4-fold increase. All Sporobolus species possessed forage quality traits (e.g. crude protein, fibre content) comparable to those of timothy, a forage grass grown widely in the Great Basin in the western United States. Micronutrient content exceeded the minimum requirements of beef cattle, without surpassing tolerable limits, with the exception of zinc, which appeared low in all three Sporobolus species. The low water requirements displayed by these species, combined with their acceptable forage qualities, indicate that these grasses have the potential to serve farmers and ranchers in semi-arid and arid regions of the western United States where Irrigation resources are limited.
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Biomass Production, Nutritional and Mineral Content of Desiccation‐Sensitive and Desiccation‐Tolerant Species of Sporobolus under Multiple Irrigation Regimes
Journal of Agronomy and Crop Science, 2013Co-Authors: Abou Yobi, Barry L Perryman, Karen Schlauch, Melvin J Oliver, John C CushmanAbstract:The development of low-water-input forages would be useful for improving the water-use efficiency of livestock production in semi-arid and arid regions. The desiccation-tolerant (DT) species Sporobolus stapfianus Gandoger and two desiccation-sensitive (DS) species, Sporobolus pyramidalis and Sporobolus fimbriatus (Trin.) Nees. (Poaceae), were evaluated for aerial biomass production and seed productivity under three different Irrigation regimes. Sporobolus stapfianus displayed the least biomass production, whereas S. pyramidalis and S. fimbriatus produced up to 3.8and 11.2-fold greater dry biomass, respectively, at the highest Irrigation rate of 12 334 l (0.01 acre-feet). Sporobolus fimbriatus and to a lesser extent S. pyramidalis showed significant increases in biomass production in response to increased Irrigation Rates, whereas S. stapfianus did not. Sporobolus pyramidalis and S. fimbriatus exhibited 3.2and 6.0-fold greater seed production, respectively, in response to increased Irrigation Rates, whereas S. stapfianus showed only a 1.4-fold increase. All Sporobolus species possessed forage quality traits (e.g. crude protein, fibre content) comparable to those of timothy, a forage grass grown widely in the Great Basin in the western United States. Micronutrient content exceeded the minimum requirements of beef cattle, without surpassing tolerable limits, with the exception of zinc, which appeared low in all three Sporobolus species. The low water requirements displayed by these species, combined with their acceptable forage qualities, indicate that these grasses have the potential to serve farmers and ranchers in semi-arid and arid regions of the western United States where Irrigation resources are limited.
Kelly T. Morgan - One of the best experts on this subject based on the ideXlab platform.
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The Effect of Irrigation Rate on the Water Relations of Young Citrus Trees in High-Density Planting
Sustainability, 2021Co-Authors: Said A. Hamido, Kelly T. MorganAbstract:The availability and proper Irrigation scheduling of water are some of the most significant limitations on citrus production in Florida. The proper volume of citrus water demand is vital in evaluating sustainable Irrigation approaches. The current study aims to determine the amount of Irrigation required to grow citrus trees at higher planting densities without detrimental impacts on trees’ water relation parameters. The study was conducted between November 2017 and September 2020 on young sweet orange (Citrus sinensis) trees budded on the ‘US-897’ (Cleopatra mandarin x Flying Dragon trifoliate orange) citrus rootstock transplanted in sandy soil at the Southwest Florida Research and Education Center (SWFREC) demonstration grove, near Immokalee, Florida. The experiment contained six planting densities, including 447, 598, and 745 trees per ha replicated four times, and 512, 717, and 897 trees per ha replicated six times. Each density treatment was irrigated at 62% or 100% during the first 15 months between 2017 and 2019 or one of the four Irrigation Rates (26.5, 40.5, 53, or 81%) based on the calculated crop water supplied (ETc) during the last 17 months of 2019–2020. Tree water relations, including soil moisture, stem water potential, and water supplied, were collected periodically. In addition, soil salinity was determined. During the first year (2018), a higher Irrigation rate (100% ETc) represented higher soil water contents; however, the soil water content for the lower Irrigation rate (62% ETc) did not represent biological stress. One emitter per tree regardless of planting density supported stem water potential (Ψstem) values between −0.80 and −0.79 MPa for lower and full Irrigation Rates, respectively. However, when treatments were adjusted from April 2019 through September 2020, the results substantially changed. The higher Irrigation rate (81% ETc) represented higher soil water contents during the remainder of the study, the lower Irrigation rate (26.5% ETc) represents biological stress as a result of stem water potential (Ψstem) values between −1.05 and −0.91 MPa for lower and higher Irrigation Rates, respectively. Besides this, increasing the Irrigation rate from 26.5% to 81%ETc decreased the soil salinity by 33%. Although increasing the planting density from 717 to 897 trees per hectare reduced the water supplied on average by 37% when one Irrigation emitter was used to irrigate two trees instead of one, applying an 81% ETc Irrigation rate in citrus is more efficient and could be managed in commercial groves.
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Effect of Various Irrigation Rates on Growth and Root Development of Young Citrus Trees in High-Density Planting.
Plants (Basel Switzerland), 2020Co-Authors: Said A. Hamido, Kelly T. MorganAbstract:Citrus yields have declined by almost 56% since Huanglongbing (HLB) was first found in Florida (2005). That reduction forced citrus growers to replant trees at much higher densities to counter-balance tree loss. The current project aims to determine how much water is required to grow citrus trees at higher planting densities without reducing their productivity. The study was initiated in November 2017 on eight-month-old sweet orange (Citrus sinensis) trees grafted on the ‘US-897′ (Cleopatra mandarin × Flying Dragon trifoliate orange) citrus rootstock planted in the University of Florida, Southwest Florida Research and Education Center (SWFREC) demonstration grove, in Immokalee, FL (lat. 26.42° N, long. 81.42° W). The soil in the grove is Immokalee fine sand (Sandy, siliceous, hyperthermic Arenic Alaquods). The demonstration grove included three densities on two rows of beds (447, 598, and 745 trees per ha) replicated four times each and three densities of three rows of beds (512, 717, 897 trees per ha) replicated six times. Each density treatment was irrigated at one of two Irrigation Rates (62% or 100%) during the first 15 months (2017–2019) then adjusted (2019–2020) to represent 26.5, 40.5, 53, and 81% based on recommended young citrus trees evapotranspiration (ETc). Tree growth measurements including trunk diameter, height, canopy volume, leaf area, and root development were evaluated. During the first year, reducing the Irrigation rate from 100% to 62% ETc did not significantly reduce the young citrus tree growth. Conversely, the lower Irrigation rate (62% ETc) had increased citrus tree’s leaf area, canopy volume and tree heights, root lifespan, and root length by 4, 9, 1, 2, and 24% compared with the higher Irrigation rate (100%), respectively. Furthermore, the root lifespan was promoted by increasing planting density. For instance, the average root lifespan increased by 12% when planting density increased from 447 to 897 trees per ha, indicating that planting young trees much closer to each other enhanced the root’s longevity. However, when treatments were adjusted from April 2019 through June 2020, results changed. Increasing the Irrigation rate from 26.5% to 81% ETc significantly enhanced the young citrus tree growth by increasing citrus tree’s canopy volume (four fold), tree heights (29%), root lifespan (86%), and root length (two fold), respectively. Thus, the application of 81% ETc Irrigation rate in commercial citrus groves is more efficient for trees from two to four years of age.
Aiwang Duan - One of the best experts on this subject based on the ideXlab platform.
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winter wheat with subsurface drip Irrigation sdi crop coefficients water use estimates and effects of sdi on grain yield and water use efficiency
Agricultural Water Management, 2014Co-Authors: Yang Gao, Linlin Yang, Xiaojun Shen, Jingsheng Sun, Aiwang DuanAbstract:Abstract Winter wheat (Triticum aestivum L.) production in the North China Plain (NCP) is threatened by insufficient water supply. Interest in microIrrigation is increasing in the NCP, while data and guidance for microIrrigation scheduling are lacking. An accurate estimation of actual crop evapotranspiration (ETa) is critical for appropriate water management. In this study, therefore, the SIMDualKc model was calibrated with the data from a three-season experiment, and ETa of winter wheat with subsurface drip Irrigation (SDI) was estimated with the dual crop coefficient approach and stress adjustments described in the FAO-56 using the data of the other two treatments. The mean value of basal crop coefficient (Kcb) for the winter wheat at the initial-, mid-, and late-season growth stages over the three seasons was 0.25, 1.06, and 0.34, respectively. Over the three growing seasons, the ETa for subsurface drip-irrigated wheat with three Irrigation treatments ranged from 393 to 449 mm. The Kc-local (ETa/ETo) values for the winter wheat with SDI were 0.34–0.80, 0.91–1.11, and 0.41–0.98, respectively, at the initial-, mid-, and late-season growth stages. Results indicated that the procedure of the dual Kc approach and stress adjustments simulated ETa of the winter wheat reasonably well, with the average absolute error (AAE) of 0.36 mm d−1, the root mean square error (RMSE) of 0.43 mm d−1,the index of agreement (d) of 0.98, the Nash–Sutcliffe efficiency (NSE) of 0.91, and the RMSE-observations standard deviation ratio (RSR) of 0.31. Discrepancy between the simulated and measured data was mainly attributed to the assumption of a uniform distribution of soil water around an emitter. Irrigation Rates have significant effects on ETa, grain yield and WUE. Based on effects of Irrigation Rates on grain yield and WUE, Irrigation schedule for optimum yield and WUE was developed for winter wheat. It was estimated that grain yield and WUE of winter wheat with the optimum Irrigation schedule was 7780 kg ha−1 and 1.83 kg m−3, respectively. The simulated results can be used as a reference for Irrigation schedule and water management for winter wheat in the NCP.
