基于WorldView-2影像的土壤含盐量反演模型

针对WorldView-2影像高空间分辨率评价其定量反演土壤含盐量的能力,以盐渍化现象较为明显的新疆克里雅河流域为研究对象,基于WorldView-2影像和实测高光谱数据,利用偏最小二乘回归(partial least squares regression,PLSR)和BP人工神经网络(back propagation artificial neural networks,BP ANN)方法建立定量反演该流域土壤含盐量模型并做出研究区高空间分辨率土壤含盐量分布图。结果表明:1)利用实测高光谱数据和影像数据分别建立的2种模型中BP神经网络模型预测精度都高于PLSR模型,其中基于影像数据建立的6:8:1结构的3层BP神经网络模型决定系数R2、均方根误差RMSE、相对分析误差RPD分别为0.851、0.979、2.337,模型的稳定性和预测能力都优于PLSR模型(R2、RMSE、RPD分别为0.814、1.139、2.007)。2)利用WorldView-2影像提高了土壤含盐量制图的空间分辨率,归一化植被指数NDVI和比例植被指数RVI较有效降低了植被覆盖与土壤水分对预测精度的影响。该文建立的考虑植被覆盖与土壤水分定量反演土壤含盐量的模型不需要复杂的参数,一定程度上满足了干旱、半干旱地区的盐渍化监测需求,可以促进WorldView-2等高空间分辨率卫星在盐渍化监测中的进一步应用。     

Carpel weight, grain length and stabilized grain water content are physiological drivers of grain weight determination of wheat

Among the yield components, grain weight is considered a conservative trait whose determination is still beyond our complete understanding. Crop physiology uses a whole approach to study this complex trait, which can provide helpful information to plant breeders and molecular biologists. This study emphasizes the understanding of pre- and post-anthesis determinants of final grain weight. A field experiment was carried out in two growing seasons evaluating two wheat cultivars contrasting in grain weight potential. Carpel weight at pollination, grain dimensions, grain water, dry matter and volume dynamics were assessed. Among grain dimensions, grain length was the trait, which explained final grain weight (r² = 0.78; P < 0.01 and r² = 0.94; P < 0.001 for the 1st and 2nd season, respectively) and it was the first trait to stabilize after anthesis. Water content of grains stabilized little later and also showed a strong association with final grain weight (r² = 0.93; P < 0.01 and r² = 0.98; P < 0.01 for the 1st and 2nd season respectively). Most importantly, carpel weight at pollination showed a positive and linear association with final grain weight (r² = 0.79, P < 0.01 and r² = 0.86 P < 0.01 for the 1st and 2nd season, respectively) irrespective of the cultivar and grain position. In addition, positive associations were also found between grain volume, water content, grain length, and carpel weight at pollination. Therefore, the associations between pre- and post-anthesis traits found in this study support the hypothesis that grain weight is determined before anthesis and fruit tissues (i.e., pericarp in cereals and sunflower) set an upper limit to grain weight.     

Direct and admixture toxicity of diatomaceous earth and monoterpenoids against the storage pests <Emphasis Type="Italic">Callosobruchus</Emphasis><Emphasis Type="Italic">maculatus</Emphasis> (F.) and <Emphasis Type="Italic">Sitophilus oryzae</Emphasis> (L.)

We investigated the effects of two commercial diatomaceous earth based insecticides (DE), Protect-It^® and SilicoSec^®, the nano-structured silica product AL06, developed by the section for Urban Plant Ecophysiology at Humboldt University Berlin, and the monoterpenoids, eugenol, and cinnamaldehyde on two stored product pests, Callosobruchus maculatus and Sitophilus oryzae. Protect-It^® was more effective than SilicoSec^® against C. maculatus while the reverse was true for S. oryzae. Generally C. maculatus was more sensitive towards DE and silica treatment than S. oryzae. Mortality rate of both pest species increased when DE’s were applied to food commodities previously treated with a monoterpenoid. In admixture experiments, the toxicity of SilicoSec^® + cinnamaldehyde (LD₅₀ = 42.73 ppm), SilicoSec^® + eugenol (LD₅₀ = 24.30 ppm), and Protect-It^® + eugenol (LD₅₀ = 2.60 ppm) was increased over DE alone against S. oryzae. Both substances showed a synergistic effect considering their co-toxicity coefficient relative to the LD₅₀-value. In contrast, we could not find any synergistic effects in experiments with C. maculatus. Here only Protect-It^® + cinnamaldehyde (LD₅₀ = 20.84 ppm) showed an additive effect while all other combinations of monoterpenoid and DE indicated antagonistic effects. In addition to contact insecticidal effects both monoterpenoids showed a strong fumigant action. The presented results indicate that the natural product DE has great potential to replace synthetic pesticides commonly used in stored product pest management. Efficacy of DE can be improved by adding certain monoterpenoids against certain insect pests.     

Evaluation of cytochrome b as a sensitive target for PCR based detection of T. annulata carrier animals

Bovine tropical theileriosis, caused by the tick-borne protozoan Theileria annulata, imposes a serious constraint upon breed improvement programmes and livestock production in tropical and sub-tropical regions of the world. Animals that recover from primary infection serve as carriers and play a critical role in the epidemiology of the disease, acting as reservoirs of infection. However, conclusive identification of carrier animals can be problematic. This study describes assessment of candidate target genes for PCR assay-based detection of T. annulata infected carrier animals. Following in silico screening and rejection of three major multi-copy gene families, an assay based on PCR amplification of a 312 bp segment of the T. annulata gene for cytochrome b (Cytob1 assay) was established. Sensitivity was evaluated using serial dilutions of blood obtained from experimentally infected calves, while specificity was confirmed by testing DNA representing twelve different T. annulata stocks and other Theileria and Babesia species. Direct comparison with other target genes and published data indicated that Cytob1 PCR-based assays provide the greatest level of sensitivity, combined with a high level of specificity and the ability to detect different T. annulata genotypes. It can be concluded that the cytochrome b gene is the optimal target for PCR amplification and its incorporation in a Reverse Line Blot Assay offers the most sensitive method yet devised to detect the parasite in carrier animals. The use of this assay will increase the accuracy of epidemiological studies aimed at improving disease control in endemically unstable regions.     

Digital image analysis to estimate the live weight of broiler

Computer assisted digital image analysis was performed to investigate the possibility of estimating body weight of live broiler. To achieve the stated objective, 100 Arbor acres broiler chicks were reared under standard rearing condition and 1200 digital images were captured from 20 randomly selected broilers during the 7-42 days growing period. The captured images were analyzed by raster image analysis software (IDRISI 32) to determine the broiler body surface area and developed a linear equation to estimate weights of the broiler from its body surface-area pixels. The developed weight predicted equation based on surface-area pixels was log W = 1.060406(log P) + 0.173756(log A) − 2.029268 (W = estimated body weight, P = surface-area pixels and A = age at weighing) and the degree of goodness of fit of this equation was 0.999. The relative error in weight estimation of broiler chicken by image analysis, expressed in terms of percent error of the residuals from surface-area pixels was in between 0.04 and 16.47. On the other hand, the estimated body weights were not significantly (p > 0.05) difference from manually measured body weights up to 35 days of age. Thus, the development of a practical imaging system for weighing live broiler is feasible.     

Protective Effect of Vitamin E against Diabetes-Induced Oxidized LDL and Aorta Cell Wall Proliferation in Rat

Background:

Hyperlipidemia and oxidized-low-density lipoproteins (Ox-LDL) are important independent cardiovascular risk factors that have been shown to stimulate vascular smooth muscle cell (VSMC) proliferation. The purpose of the present study was to investigate the effect of vitamin E on Ox-LDL, lipid profile, C-reactive protein (CRP), and VSMC proliferation of rat aorta.

Methods:

Male Wistar rats (n = 32) were divided into four groups namely: sham (SH), control (C), non-treated diabetic, and vitamin E-treated diabetic (VETD) groups. Ox-LDL, lipid profile, CRP and VSMC proliferation of aorta were measured after 42 days.

Results:

The results revealed that along with a significant increase in VSMC proliferation, the amount of CRP, Ox-LDL, and lipid profiles in diabetic rats. VSMC proliferation was significantly ameliorated, and elevated CRP, Ox-LDL, and lipid profiles were also restored to those of shams in VETD.

Conclusions:

These findings strongly support the idea that diabetes induces Ox-LDL-mediated oxidative stress and VSMC proliferation in aorta of rat and imply that vitamin E has a strong protective effect as an antioxidant. Key Words: Ox-LDL, Vitamin E, Diabetes, VSMC proliferation     

Gut melatonin response to microbial infection in carp <Emphasis Type="Italic">Catla catla</Emphasis>

The purpose of present study was to demonstrate the response of gut melatoninergic system to Aeromonas hydrophila infection for 3 or 6 days and search for its correlation with the activity of different antioxidative and digestive enzymes to focus their interplay under pathophysiological conditions in carp (Catla catla). Microscopic study of gut in infected fish revealed degenerative changes in the tunica mucosa and lamina propria layers with sloughed off epithelial cells in the lumen. The activity of each digestive enzyme was reduced, but the levels of melatonin, arylalkylamine-N-acetyl transferase protein, the key regulator of melatonin biosynthesis, and different enzymatic antioxidants in gut were gradually and significantly increased with the progress of infection. Gut melatonin concentrations in A. hydrophila challenged carp by showing a positive correlation with the activity of each antioxidative enzyme, and a negative correlation with different digestive enzymes argued in favor of their functional relation, at least, during pathological stress. Moreover, parallel changes in the gut and serum melatonin titers indicated possible contribution of gut to circulating melatonin. Collectively, present carp study provided the first data to suggest that endogenous gut melatonin may be implicated to the mechanism of response to microbial infections in any fish species.     

Effect of hybrid ratio and laminate geometry on compressive properties of carbon/glass hybrid composites

Intra-layer and inter-layer hybrid composite laminates were made with epoxy resin and compositions were varied in six different proportions. In-plane compressive mechanical properties were studied using finite element analysis and experiments, and the results found were in good agreement. Properties of intra-layer and inter-layer hybrids were compared with plain carbon/epoxy and plain glass/epoxy composites, and a comparison among themselves was also made. It was found that intra-layer hybrids to some extent exhibit better compressive properties compared to inter-layer hybrids. Percentage enhancement in compressive failure strain was noticed. Negative hybrid effects on compressive strength was noticed for both intra-layer and inter-layer hybrid configurations. It was found that proportion of carbon fiber content plays a key role in determining the compressive properties. According to macro-scale observation all composite laminates failed catastrophically under compressive loading. SEM observation depicted that under compressive loading carbon fibers break first followed by glass fiber.     

Hatchery seed production of giant freshwater prawn,Macrobrachium rosenbergii using inland ground saline water in India

The suitability of inland saline water (ISW) from the Lahli‐Baniyani Fish Farm, Rohtak was investigated for the larval rearing of giant freshwater prawn (GFP), Macrobrachium rosenbergii. Six experiments were conducted. In Experiment‐I, 54% of the larvae metamorphosed to postlarvae (PL) in constituted seawater (CSW) whereas total mortality occurred at larval stages (LS)‐II and LS‐III in ISW with salinity of 12 g L^?1. Larvae survived to LS‐IV in Experiment‐II, when ISW was supplemented with K⁺~ SW. In Experiment‐III, total hardness in ISW was reduced serially, but K⁺ ~ SW was supplemented. The larvae did not survive beyond LS‐V. In Experiment‐IV, ISW was amended with different ratios of Mg²⁺/Ca²⁺ and K⁺ ~ SW. The larvae successfully metamorphosed to postlarvae with highest survival of 51.6% in Mg²⁺/Ca²⁺ ratio of 2.5. In Experiment‐V, eight larval cycles were run with water quality used in Experiment V, where all the cycles produced PL's with a survival rate of 20–67%. In Experiment VI, the larvae were reared in Mg²⁺/Ca²⁺ ratio of 2.5 and different levels of K⁺ to optimize its requirement. The ISW amended with K⁺ 80% ~ SW and Mg²⁺/Ca²⁺ ratio of 2.5 was found to be commercially suitable for the seed production of GFP.     

N<Subscript>2</Subscript>O emission from conventional and minimum-tilled soils

In this study, we investigated N₂O emissions from two fields under minimum tillage, cropped with maize (MT maize) and summer oats (MT oats), and a conventionally tilled field cropped with maize (CT maize). Nitrous oxide losses from the MT maize and MT oats fields (5.27 and 3.64 kg N₂O-N ha⁻¹, respectively) were significantly higher than those from the CT maize field (0.27 kg N₂O-N ha⁻¹) over a period of 1 year. The lower moisture content in CT maize (43% water-filled pore space [WFPS] compared to 60–65%) probably caused the difference in total N₂O emissions. Denitrification was found to be the major source of N₂O loss. Emission factors calculated from the MT field data were high (0.04) compared to the CT field (0.001). All data were simulated with the denitrification decomposition model (DNDC). For the CT field, N₂O and N₂O + N₂ emissions were largely overestimated. For the MT fields, there was a better agreement with the total N₂O and N₂O + N₂ emissions, although the N₂O emissions from the MT maize field were underestimated. The simulated N₂O emissions were particularly influenced by fertilization, but several other measured N₂O emission peaks associated with other management practices at higher WFPS were not captured by the model. Several mismatches between simulated and measured \textNH₄⁺ {\text{NH}}_4^ + , \textNO₃^- {\text{NO}}_3^ - and WFPS for all fields were observed. These mismatches together with the insensitivity of the DNDC model for increased N₂O emissions at the management practices different from fertilizer application explain the limited similarity between the simulated and measured N₂O emissions pattern from the MT fields.