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61.
Ebadi Arash Raja Omid Ebrahimian Hamed Yazdani Mohammad Reza Rezaverdinejad Vahid 《Paddy and Water Environment》2022,20(1):151-151
Paddy and Water Environment - 相似文献
62.
Hajar Eftekhari Babs Surujlal Vahid Shadparvar 《Journal Of Agricultural & Food Information》2013,14(4):274-289
The aim of this study was to identify rice supervising agents' educational needs in the field of multifunctional agriculture in Guilan Province, Iran. The statistical population included rice supervising agents in Guilan Province in 2014 (N = 169), of which 106 people were randomly sampled. The data collection tool was a research-designed questionnaire which was filled out by respondents using the self-reporting method. Results showed that among production functions of agriculture, rice supervising agents had a high need to be trained in the functions of “the production of raw material for rural handicrafts,” “the production of animal feed,” and “the production of medicinal herbs for medical and pharmaceutical purposes.” Participants' needs for training in nonproduction functions of agriculture were ranked by the Friedman test; results indicated a great need for education in the environmental functions of agriculture and a lesser need for education in its economic functions. 相似文献
63.
ABSTRACTThis paper investigates the effect of rotation speed and vibration response of a circular saw on the sawing process of Douglas-fir wood. An idling test was conducted on a guided circular saw to determine its stable operation speeds and vibration behavior. Short-time Fourier transform analysis was performed on saw idling test data, and variation of excited frequencies of the blade as a function of rotation speed was obtained. The saw blade critical speeds and the rotation speeds that correspond to saw flutter instability were identified. Then experimental cutting tests were conducted at different cutting conditions and the effect of rotation speed and saw vibration response on cutting power consumption and sawing accuracy was investigated. The results showed that conducting a saw idling test and vibration response analysis can identify the saw critical and flutter speeds, which is essential for identifying the optimum rotation speed of circular saw. There was a significant increase in power consumption when cutting at super-critical and super-flutter speed. The effect of rotation speed on sawing accuracy is complex and nonlinear. This effect interacts with feed speed, which makes it difficult to generalize sawing accuracy versus rotation speed in the circular sawing process. 相似文献
64.
Ramin Hosseinzadeh Javad Soosani Vahid Alijani Sheyda Khosravi Hamdieh Karimikia 《林业研究》2016,27(5):1137-1141
Topography is the most factor that has the greatest impact of all factor that affect the distribution.To study the diversity of trees and shrub species in the Perc forest situated in Khorramabad,Lorestan,140 circular plots of 1200 m~2 in a grid of 300 m 9 250 m were surveyed,using a systematic random sampling method.In each plot,the Margalef richness index,Shannon–Wiener diversity index,Hill's N_1 and Simpson indices and the evenness index of Simpson and Smith-Wilson were calculated and ordered on the basis of different classes of elevation,exposition and slope.The results indicated that slope did not have any significant effect on the indices.Exposition and elevation classes significant impacted the richness and diversity indices,but did not influence evenness.In general,the highest plant diversity was observed for slopes less than 15 %,northern aspects,without geographical direction,and elevations of 2100–2200 m.This information can be very useful in achieving the goals for sustainable management of forests.In addition to greater protection for regions with high diversity and reforestation(compatible species) in degraded area,we can help increase diversity in forests. 相似文献
65.
Faramarz Gharagozlou Reza Youssefi Vahid Akbarinejad Javad Ashrafihelan 《Journal of Equine Veterinary Science》2013
Anti-Müllerian hormone (AMH), produced by granulosa cells, has been reported to be elevated in mares with granulosa cell tumor. A 13-year-old Arabian mare was referred after 3 years of infertility. Rectal and ultrasonographic examination revealed enlargement and multicystic appearance of the left ovary. The mare had substantially higher concentration of AMH (21.6 ng/mL) compared with normal cyclic mares (n = 5; 0.36 ± 0.02 ng/mL). Testosterone (50 pg/mL) concentration was also elevated, but progesterone concentration (0.4 ng/mL) was lowered. Accordingly, the mare was presumptively diagnosed with granulosa-theca cell tumor and a left ovariectomy implemented using ventral midline approach under general anesthesia. Histopathological examination confirmed the diagnosis of granulosa-theca cell tumor. Serum concentrations of AMH decreased to 2 ng/mL and 0.5 ng/mL 2 and 4 weeks after tumor removal, respectively. In conclusion, the current report presents confirmatory evidence that evaluation of serum AMH could be useful for diagnosis of granulosa cell tumor in mare. 相似文献
66.
Journal of Plant Diseases and Protection - Grapevine Pinot gris virus (GPGV) was firstly identified in northern Italy by deep sequencing from grapevine cv. Pinot gris, exhibiting mottling and... 相似文献
67.
Nasrin Nasiri Mohammad R.Marvie Mohadjer Vahid Etemad Kiomars Sefidi Leila Mohammadi Maryam Gharehaghaji 《林业研究》2018,(4)
For developing nature-based silvicultural practices in a beech forest to promote, abundance, height,vitality, and preferred growth form, regenerated trees growing in gaps were compared with those under closed canopies.A systematic 50×50 m grid was plotted in a beech stand in the Kheyrud Experimental Forest for selecting trees to measure variables in gaps and under closed canopies.Abundance and mean height of regenerated beech trees were significantly higher in closed canopies than in canopy gaps.Beech seedlings with excurrent growth were significantly taller within regeneration patches under closed canopy.Moreover, regenerated trees with high vitality were more abundant in closed canopy areas than in gaps.Thus, beech regeneration should improve under closed canopies; hence, gaps in a near natural forest should be created only after adequate regeneration and appropriate growth under the parent tree in a closed canopy area is ensured.The results of this research have profound implications for the sustainable management of the forest and for ensuring sustainable beech regeneration.The presence of a closed canopy cover likely will reduce potential stresses on oriental beech regeneration. 相似文献
68.
Nasrin Azad Vahid Rezaverdinejad Heydar Tayfeh Rezaie 《Archives of Agronomy and Soil Science》2018,64(5):731-746
In this research, impact of climate change on wheat yield was simulated using SWAP in Myandoab, Iran. Field data of wheat in 2004–2005 and 2005–2006 periods were used for calibration and validation of the SWAP, respectively. The HadCM3 outputs, for A1B, A2 and B1 scenarios and 2046–2065 periods, were used in SWAP and wheat yield in mentioned period was compared with base period. Three irrigation levels, based on meeting 100, 70 and 50% of the crop ET demand, were used to study the climate change effects on wheat yield in full and deficit irrigation conditions. The results showed that temperature and reference evapotranspiration will increase in 2055s. Temperature increase cause to decrease crop growing period and crop evapotranspiration. The results showed that the negative impact of temperature increase has dominated to the positive impact of CO2 concentration and the yield is reduced. For full irrigation situation, the reduction will be 24.1, 22.4 and 20.8% in A1B, A2 and B1, respectively. Reduction in yield can be related to the shorter maturity period of the crop. The results showed that under deficit irrigation, the yield is also decreased but this decrease rate of yield is higher in full irrigation. 相似文献
69.
Mahsa Fallah Vahid Hosseini Gholamhossein Moravej D. J. Eldridge 《Arid Land Research and Management》2017,31(2):159-168
Livestock grazing is a major driver of ecosystem functions in drylands and would be expected to influence soil biota such as termites. We examined changes in soil chemistry and plant community composition on mounds constructed by the subterranean termite Anacanthotermes ahngerianus along a gradient in grazing intensity in an arid steppe in north-eastern Iran. The grazing gradient was represented by increasing distance from an area used by resting livestock, and plant and soil attributes measured within three adjacent microsites (termite mounds, non-mound controls, intervening annular zone surrounding the mounds). Values of soil EC; pH; exchangeable Ca, Mg, and Na; and total nitrogen and organic carbon were greatest in mound soils and declined from mounds to control microsites. Mounds were completely devoid of plants. Annular zones had three-times less cover than the control sites, but there were no differences in diversity or evenness. Electrical conductivity values were ten-times greater on mounds than controls close to resting sites, but the difference diminished rapidly with distance from resting sites. For all other soil and plant variables, differences between microsites were consistent across the grazing gradient. Increased grazing intensity was associated with increasing soil pH, EC and sand content, and reduced plant cover. Overall our study shows that the effects of termites on soil chemistry and plant cover varied little across the grazing gradient. Our results suggest that termite mounds may sustain their role as sites of enhanced soil nutrients under even high levels of grazing. 相似文献
70.
Vahid Ghodrat Reza Hamidi Forood Bazrafshan Shahram Sharafzadeh 《Communications in Soil Science and Plant Analysis》2017,48(11):1343-1358
To determine the effect of water deficit on growth characteristics of 27 cotton cultivars (Gossypiumhirsutum L.), two separate experiments were performed in laboratory and glasshouse in Fars Province, Zarin-Dasht city (28° 36′ N, 54° 41′ E) in August 2015. In both experiments, which last for 10 days, a completely randomized block design with three replications was used. The main factor was water-deficit levels ((0, ?4, and ?12 MPa in laboratory and (0 and ?8 MPa) in glasshouse experiments), and the subsidiary factor was different cotton cultivars. The sensitivity to water deficit was compared based on factors such as germination rate, shoot and root lengths, fresh and dry weights, seed energy, and seed vigor. The results of both experiments indicated that Oltan, Opal, Pak, Armaghan, Super-Elit Golestan, Super-Elit Bakhteghan, SB-35, Super-Elit Arian, Khandagh, Tabela-18, and Sahel cultivars are more resistant and therefore are suitable candidates to increase plant density and uniformity in the farm. 相似文献