ABSTRACT
Natural habitats play crucial roles in biodiversity conservation and shape the delivery of ecosystem services in farming landscapes. By providing diverse resources to foraging natural enemies, they can equally enhance biological pest control. In this study, we described the plant community and foliage-dwelling invertebrate predators within non-crop habitats of the Gobi Desert oases in southern Xinjiang, China. We assessed whether plant-related variables (i.e., species identity, flowering status) and herbivore abundance affect natural enemy identity and abundance. A total of 18 plant species belonging to 18 genera and 10 families were commonly encountered, with Apocynum pictum (Apocynaceae), Phragmites communis (Poaceae), Karelinia caspia (Asteraceae), and Tamarix ramosissima (Tamaricaceae) as the dominant species. Certain plant species (P. communis) primarily provide shelter, while others offer (floral, non-floral) food resources or alternative prey. Predatory ladybeetles and spiders were routinely associated with these plants and foraged extensively within adjacent field crops. Plant traits and herbivore abundance explained up to 44% (3%-44%) variation in natural enemy community and exhibited consistent, year-round effects. Among all plant species, A. pictum consistently had a significantly higher abundance of resident natural enemies, except for August 2019. Our study underlines how perennial flowering plants, such as A. pictum, are essential to sustain natural enemy communities and related ecosystem services in arid settings. This work not only informs sustainable pest management initiatives but also shows how non-crop habitats at the periphery of agricultural fields underpin ecological resilience under adverse climatic conditions.
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Background: Difficulties in detecting brain lesions in acute ischemic stroke (AIS) have convinced researchers to use computed tomography (CT) to scan for and magnetic resonance imaging (MRI) to search for these lesions. This work aimed to develop a generative adversarial network (GAN) model for CT-to-MR image synthesis and evaluate reader performance with synthetic MRI (syn-MRI) in detecting brain lesions in suspected patients. Methods: Patients with primarily suspected AIS were randomly assigned to the training (n=140) or testing (n=53) set. Emergency CT and follow-up MR images in the training set were used to develop a GAN model to generate syn-MR images from the CT data in the testing set. The standard reference was the manual segmentations of follow-up MR images. Image similarity was evaluated between syn-MRI and the ground truth using a 4-grade visual rating scale, the peak signal-to-noise ratio (PSNR), and the structural similarity index measure (SSIM). Reader performance with syn-MRI and CT was evaluated and compared on a per-patient (patient detection) and per-lesion (lesion detection) basis. Paired t-tests or Wilcoxon signed-rank tests were used to compare reader performance in lesion detection between the syn-MRI and CT data. Results: Grade 2-4 brain lesions were observed on syn-MRI in 92.5% (49/53) of the patients, while the remaining syn-MRI data showed no lesions compared to the ground truth. The GAN model exhibited a weak PSNR of 24.30 dB but a favorable SSIM of 0.857. Compared with CT, syn-MRI led to an increase in the overall sensitivity from 38% (57/150) to 82% (123/150) in patient detection and from 4% (68/1,620) to 16% (262/1,620) in lesion detection (R=0.32, corrected P<0.001), but the specificity in patient detection decreased from 67% (6/9) to 33% (3/9). An additional 75% (70/93) of patients and 15% (77/517) of lesions missed on CT were detected on syn-MRI. Conclusions: The GAN model holds potential for generating synthetic MR images from noncontrast CT data and thus could help sensitively detect individuals among patients with suspected AIS. However, the image similarity performance of the model needs to be improved, and further expert discrimination is strongly recommended.
ABSTRACT
Resource-continuity over spatial and temporal scales plays a central role in the population abundance of polyphagous pests in an agricultural landscape. Shifts in the agricultural land use in a region may alter the configuration of key resource habitats, resulting in drastic changes in pest abundance. Apolygus lucorum (Meyer-Dür) (Hemiptera: Miridae) is a pest of cotton in northern China that has become more serious in recent years following changes in the region's cropping systems. However, no evidence from the landscape perspective has yet been gathered to account for the increasing population of A. lucorum in China. In this study, we investigated the effects of landscape composition on the population abundance of A. lucorum in cotton fields in July and August of 2016, respectively. We found that increased acreage planted to cotton actually had a negative effect on the abundance of A. lucorum, while planting of other crops (e.g., vegetables, soybean, and peanut) was positively associated with the mirid's population abundance in cotton fields. Maize production only displayed a positive effect on population abundance in August. Our results suggested that the decreasing of cotton area may weaken the trap-kill effect on A. lucorum, and the extension of other crops and maize potentially enhance the continuity of resources needed by A. lucorum. Combined effects of these two aspects may promote an increased population density of A. lucorum in the agriculture district. In the future, when possible, management strategies in key regional crops should be coordinated to reduce resource continuity at the landscape or area-wide scale to lower A. lucorum populations across multiple crops.
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BACKGROUND: Although the abundance of insect natural enemies in crop fields may be influenced by the surrounding landscape and local field management, particularly insecticide use at the local scale, few studies have examined these factors simultaneously. In this study, we investigated the effects of landscape context and insecticide use in local fields on ladybeetle abundance in wheat fields in northern China. RESULTS: Woodlots and fallow land were the most important landscape variables enhancing ladybeetle abundance. We used the cumulative percentage of these land types to characterize landscape complexity. Comparing the change in ladybeetle abundance in wheat fields within different landscapes and with different in-field insecticide regimes, we found that although more complex landscapes enhanced ladybeetle abundance, the negative effects of insecticide use on ladybeetle populations were not offset by landscape complexity. Additionally, the positive effects of more complex landscapes on ladybeetle abundance were not significant in wheat fields subjected to high insecticide use. CONCLUSION: Ladybeetle abundance is enhanced by landscape complexity, but this is modified by insecticide use in local fields. Within-field efforts to maximize the conservation biological control of pests to improve crop yield should take into account the influence of the surrounding landscape. © 2018 Society of Chemical Industry.
Subject(s)
Coleoptera , Insecticides , Triticum , Animals , SeasonsABSTRACT
OBJECTIVE: To explore the effects of oral vitamin D supplementation on anthropometric parameters and insulin resistance (IR) in type 2 diabetes mellitus (T2DM). METHODS: A total of 164 subjects with T2DM, aged 30-75 years, were randomly divided into two groups of intervention and control. The intervention group received a daily dose of 0.50 µg calcitriol while the control group maintained the original treatment regimen. At the beginning and end of 12-week supplementation trial, the demographic and anthropometric data were recorded and the serum levels of glucose, insulin, HbA1C and 25(OH)D measured. IR was assessed by the homeostasis model approximation index. RESULTS: There was no significant inter-group difference at baseline. Compared with the baseline level, body mass index (BMI) ((-0.7 ± 1.7) vs (-0.4 ± 1.4) kg/m(2)) (P < 0.05), waist circumference (WC) ((-1.3 ± 1.3) vs ( -0.2 ± 1.1) cm) (P < 0.05) , fasting plasma glucose (FPG) ((-1.2 ± 2.3) vs (-0.6 ± 2.8) mmol/L) , fasting plasma insulin (FPI) ((-1.6 ± 2.2) vs (-0.32 ± 1.49) µU/ml) (P < 0.05), HbA1C ((-0.1 ± 0.6) vs (-0.03 ± 0.94))(P < 0.05), HOMA-IR ((-0.91 ± 2.63) % vs (-0.15 ± 1.78) %)(P < 0.05) and 25(OH)D ((20 ± 17) vs (1.0 ± 3.3) ng/ml) (P < 0.05) decreased obviously in the intervention group at the end of study. After stratifying by different baseline serum levels of 25(OH)D, HOMA-IR significantly decreased after supplementation in < 20 ng/ml group ((6 ± 3) vs (5 ± 3) ) (P < 0.05) , 20-30 ng/ml group ((6 ± 3) vs (5 ± 3)) (P < 0.05) and >30 ng/ml group ((5 ± 3) vs (4 ± 3)) (P < 0.05) . And BMI ((26 ± 6) vs (26 ± 4) kg/m(2)) (P < 0.05) , WC ((84 ± 11) vs (82 ± 12) cm) (P < 0.05) , FPG ((8 ± 4) vs (6 ± 4) mmol/L) (P < 0.05), FPI ((17 ± 4) vs (16 ± 4) µU/ml) (P < 0.05) and HbA1C((7.4 ± 0.9) % vs (7.0 ± 1.2) %) (P < 0.05) decreased statistically significant only in 15-20 ng/ml group. Multivariate regression analysis showed that HOMA-IR was a significant independent risk factor for 25 (OH) D (OR = 13, 95%CI = 4-39, P < 0.05). CONCLUSION: There are significant improvements in BMI, WC, FPG, FPI, HbA1C and HOMA-IR after supplementation. Thus vitamin D supplementation may reduce insulin resistance in T2DM.
