基于多维高光谱植被指数的冬小麦叶面积指数估算     

吾木提·艾山江  尼加提·卡斯木  陈晨  买买提·沙吾提 《农业机械学报》2022,53(5):181-190

为提高干旱区冬小麦叶面积指数（Leaf area index, LAI）遥感估算精度,以拔节期冬小麦LAI为研究对象,在对冠层高光谱数据进行一阶（First derivative, FD）、二阶（Second derivative, SD）微分预处理的基础上,计算了任意波段组合的二维植被指数（Two-dimensional vegetation index, 2DVI）和三维植被指数（Three-dimensional vegetation index, 3DVI）,通过进行与LAI之间相关性分析,寻求最佳波段组合的植被指数;利用人工神经网络（Artificial neural network, ANN）、K近邻（K-nearest neighbors, KNN）和支持向量回归（Support vector regression, SVR）算法分别建立LAI估算模型,并进行精度验证。结果表明：任意波段组合的植被指数与LAI相关性均显著提高,尤其是基于一阶微分预处理光谱的FD-3DVI-4（714 nm, 400 nm, 1 001 nm）相关系数达到0.93（P<0.01）,且最...  相似文献   

Stereochemical basis for the insecticidal activity of carbamoylated and acylated pyrazolines     

Riaz Hasan  Keiichiro Nishimura  Masakazu Okada  Miki Akamatsu  Masafumi Inoue  Tamio Ueno  Tooru Taga 《Pest management science》1996,46(2):105-112

Methyl 3-(4-chlorophenyl)-1-[N-(4-chlorophenyl)carbamoyl]-4-methyl-2-pyrazoline-4-carboxylate was converted to corresponding (1R)- and (1S)-phenethyl esters via its carboxylic acid and acid chloride at the C-4 atom to separate the diastereomers. Their configurations were confirmed by X-ray analysis. Both isomers of the (1R)methylbenzyl ester were subjected to transesterification with sodium methoxide to obtain enantiomers of the starting methyl ester. Their insecticidal activity was measured against American cockroaches (Periplaneta americana (L.)) by injection and against house flies (Musca domestica L.) by topical application under various synergistic conditions with metabolic inhibitors. The activity values of the four α-methylbenzyl esters and the R-isomer of the starting methyl ester were similar. The S-enantiomer of the methyl ester was about 10 and 100 times more active than the R-isomer against the cockroach and the fly, respectively. Some N-arylacetyl and N-aryloxyacetyl derivatives of the starting N-(4-chlorophenyl)carbamoyl compound gave very low activity. Conformation-energy profiles for some compounds suggested that the conformation of substituents on the N-1 atom in the pyrazoline ring has a specific role for the potential insecticidal effects.  相似文献   

Removal of cadmium from aqueous solution by a soil containing magnesite     

Berrin Ziyadanoğullari  Firat Aydin  Işil Aydin  Hasan Bingöl 《Archives of Agronomy and Soil Science》2013,59(4-5):371-376

Removal of Cd (II) from aqueous solution by a soil containing magnesite and thermal activated soil containing magnesite was investigated. Maximum activation temperature was determined at 700°C for 2?h and maximum adsorption capacities were determined as 4.20?mg/g for natural magnesite, 38.91?mg/g for thermal activated magnesite at 25°C respectively. Equilibrium contact time of cadmium was determined for 2?h. Adsorption of Cd (II) on soil containing magnesite conforms to Langmuir's isotherm.  相似文献   

Effect of kenaf and EFB fiber hybridization on physical and thermo-mechanical properties of PLA biocomposites     

Md. Saiful Islam  Irmawati Binti Ramli  M. R. Hasan  Md. Moynul Islam  Kh. Nurul Islam  Mahbub Hasan  Ahmad Saffian Harmaen 《Fibers and Polymers》2017,18(1):116-121

Kenaf/empty fruit bunch/polylactic acid (kenaf/EFB/PLA) hybrid biocomposites were prepared using hot press technique. The ratio of fiber to polylactic acid was set at 60:40 with 1:1 ratio between kenaf and empty fruit bunch fibers. Physical, mechanical and thermal properties of hybrid biocomposites were subsequently characterized using Fourier transform infrared spectroscopy, scanning electron microscope, X-ray diffraction, thermogravimetric analysis, differential scanning calorimetry, tensile and water absorption tests. Test results indicated that mechanically stronger fiber was able to support the weaker fiber. Hybrid fiber biocomposite had higher crystallinity as compared to single fiber biocomposite. Water absorption of hybrid composite was higher as compared to single fiber composite. Thermal result revealed that hybridization of fiber was not significantly influence the thermal properties of composites. However, the presence of two different fibers proposed good wettability properties, which could reduce the formation of voids at the fibers-polymer interface and produce composites with high stiffness and strength.  相似文献   

An Empirical Analysis on the Determinants of Government-subsidised Crop Insurance Purchase in Grape Production in Turkey   总被引：1，自引：0，他引：1  

Hasan Yilmaz  Meltem Merkez  Nukhet Unlu 《Erwerbs-Obstbau》2017,59(1):51-60

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Effects of soil tillage,canola (Brassica napus L.) cultivars and planting date on canola yield,and oil and some biological and physical properties of soil     

Hossein Torabi  Hasan Ali Naghdibadi  Hossein Omidi  Heshmat Amirshekari 《Archives of Agronomy and Soil Science》2013,59(2):175-188

Determination of different agronomical properties including soil-related parameters for enhanced canola (Brassica napus L.) production can be of great significance. Hence, the objectives were to determine the effects of different tillage systems, canola cultivars and different planting dates on: (i) canola yield and oil, and (ii) soil moisture and microbial carbon (C) and nitrogen (N). Two field experiments were planned as split-plot experiments in three replicates. The main plots were different tillage systems including no-tillage (NT), minimum tillage (MT) and conventional tillage (CT), and the subplots were the combination of different canola cultivars (PF and Hyola 401) and different planting dates (PD): 8 and 23 September and 7 October. Soil moisture under CT and PF was significantly less than that of MT and NT, and Hyola 401, respectively. Carbon and N microbial biomass was the highest at NT and on the first PD. The tillage method and planting date also significantly affected canola yield, oil content and the amount, and the number of earthworms. We may conclude that although the amount of yield was the highest at CT, it may be more agronomically sustainable to plant canola under NT or MT earlier during the autumn growing season.  相似文献   

Employment volatility in lagging and advanced regions: The Italian case     

Hasan Engin Duran  Ugo Fratesi 《Growth and change》2020,51(1):207-233

The presence of cycles characterizes all economic systems, but economic cycles have differentiated spatial impacts. Some regions have broader cycles with respect to the country, while others tend to be less responsive to shocks and hence have narrower cycles. Being exposed to broader cycles, that is, greater volatility, may increase the strain on a regional economic system. This paper investigates the different responsiveness to cyclical forces and volatility of regions in the long run. It does so by using quarterly employment data for the Nuts2 Italian regions over almost 40 years before and during the period 1978–2016. Explored in particular are the cross-regional variations in employment volatility and the reasons for the patterns observed, as well as whether they have changed the following different macroeconomic policy regimes. The paper identifies the break dates of different regimes, and these regime changes will be related to policy modifications, such as the implementation of the European Monetary Union. The determinants of this regional volatility appear to be quite stable, so that the changes in volatility are explained by how these determinants have changed overtime and how they are unevenly distributed in space. In particular, the lagging regions of the country suffer, in addition to lower production and income, from higher volatility due to a structure which is weaker and more unstable. Volatility can hence be an additional issue for lagging regions.  相似文献   

Economic Analysis of Integrated Pest Management Adoption in Apple Cultivation: a Turkish Case Study     

Mevlüt Gül  Metin Göksel Akpinar  Vecdi Demircan  Hasan Yilmaz  Tufan Bal  Ş. Evrim Arici  Mehmet Polat  Bekir Şan  Figen Eraslan  M. Çağla Örmeci Kart  Damla Gurbuz  Şerife Gülden Yilmaz 《Erwerbs-Obstbau》2017,59(2):147-154

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Insecticide resistance compromises the control of Aedes aegypti in Bangladesh     

Hasan Mohammad Al-Amin  Narayan Gyawali  Melissa Graham  Mohammad Shafiul Alam  Audrey Lenhart  Leon E Hugo  Gordana Rašić  Nigel W Beebe  Gregor J Devine 《Pest management science》2023,79(8):2846-2861

BACKGROUND

With no effective drugs or widely available vaccines, dengue control in Bangladesh is dependent on targeting the primary vector Aedes aegypti with insecticides and larval source management. Despite these interventions, the dengue burden is increasing in Bangladesh, and the country experienced its worst outbreak in 2019 with 101 354 hospitalized cases. This may be partially facilitated by the presence of intense insecticide resistance in vector populations. Here, we describe the intensity and mechanisms of resistance to insecticides commonly deployed against Ae. aegypti in Dhaka, Bangladesh.

RESULTS

Dhaka Ae. aegypti colonies exhibited high-intensity resistance to pyrethroids. Using CDC bottle assays, we recorded 2–24% mortality (recorded at 24 h) to permethrin and 48–94% mortality to deltamethrin, at 10× the diagnostic dose. Bioassays conducted using insecticide–synergist combinations suggested that metabolic mechanisms were contributing to pyrethroid resistance, specifically multi-function oxidases, esterases, and glutathione S-transferases. In addition, kdr alleles were detected, with a high frequency (78–98%) of homozygotes for the V1016G mutation. A large proportion (≤ 74%) of free-flying and resting mosquitoes from Dhaka colonies survived exposure to standard applications of pyrethroid aerosols in an experimental free-flight room. Although that exposure affected the immediate host-seeking behavior of Ae. aegypti, the effect was transient in surviving mosquitoes.

CONCLUSION

The intense resistance characterized in this study is likely compromising the operational effectiveness of pyrethroids against Ae. aegypti in Dhaka. Switching to alternative chemical classes may offer a medium-term solution, but ultimately a more sustainable and effective approach to controlling dengue vectors is required. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.  相似文献   

Antibacterial activity and cytotoxicity of extractives from Uvaria hamiltonii stem bark   总被引：2，自引：0，他引：2  

Asha KN  Chowdhury R  Hasan CM  Rashid MA 《Fitoterapia》2003,74(1-2):159-163

The extracts as well as piperolactum C, goniopedaline, 6beta-hydroxystigmasta-4,22-dien-3-one and a mixture of cis- and trans-4-hydroxymelleins obtained from Uvaria hamiltonii stem bark exhibited mild to moderate in vitro antibacterial activity. The results obtained were compared with a standard antibiotic, kanamycin. In a brine shrimp lethality bioassay the pet-ether, dichloromethane, methanol extracts and a major alkaloid, piperolactum C were found to exhibit mild to moderate cytotoxicity.  相似文献