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1.
《Journal of dairy science》2022,105(2):1099-1114
Variability of protein and energy supply from pasture during the grazing season is a primary factor that can influence milk production of grazing organic dairy herds in the Northeast United States. This study evaluated the effects of altering the crude protein (CP) content of dietary supplements included in dairy rations fed to grazing organic dairy herds, on milk production and composition. Six commercial organic farms participated in a 6-wk trial, consisting of a 2-wk baseline period and 4-wk experimental period. Farms were paired by their summer 2017 milk urea nitrogen profile, and farms within each pair were assigned by restricted randomization to (1) continuation of their regular supplements (n = 3, control group, CON), or (2) supplement with altered CP as percentage of dry matter, formulated using an organic barley and roasted soybean mix (n = 3, treatment group, TRT). Throughout the 6-wk trial, individual milk samples were collected at 2 consecutive milkings weekly, while pasture and supplement samples, pasture measurements, and management information were collected twice weekly per farm. Data were statistically analyzed using the MIXED procedure of SAS (version 9.4, SAS Institute Inc.) for all parameters, and effects of treatment, week, and their interaction (treatment × week) were determined. The supplement CP (percentage of dry matter) during the baseline period was 13.5% for CON and 15.3% for TRT and 14.8% for CON and 19.3% for TRT during the experimental period. Milk production was 21% higher during the experimental period for TRT compared with CON (24.1 vs. 19.9 kg of milk per day, respectively). Milk production decreased for CON from wk 1 to wk 6 (23.6 vs. 20.4 kg of milk per day), whereas TRT maintained milked production from wk 1 to wk 6 (22.8 vs. 22.7 kg of milk per day). Milk composition was different between groups, with CON having higher fat percent (4.21 vs. 3.73%, respectively) and protein percent (3.15 vs. 3.05%, respectively) compared with TRT for the 6 wk. The milk urea nitrogen concentrations were similar between TRT and CON for the baseline period (11.9 vs. 12.1 mg/dL) and the final week of the experimental period (14.5 vs. 14.2 mg/dL). Although the effects of different diet CP fractions, particularly rumen undegradable protein and soluble protein, must be further delineated, these results indicate that altering the CP content of dietary supplements fed to grazing organic dairy cattle during the summer period in the Northeast US could be a useful mechanism to maintain milk production.  相似文献   
2.
Previous studies reported coastal trapped waves (CTWs) in the Caspian Sea (CS). This study deals with the generation mechanisms, the temporal and spatial variability of CTWs in this area, and their transformations during propagation from the origin to the destination using recent measurements and high-resolution numerical simulations. CTWs are observed at all stations with periods of 2–6 days after northerly storms. The Absheron Peninsula, old Sefidrud delta, and Nur coasts were identified as the CTWs prone regions. The generation of CTWs in these locations was confirmed using numerical experiments. The propagation away from the generating location of CTWs was analyzed using a representative real wind storm. In the west part of the CS, the generation mechanism of CTWs is mainly similar to the barotropic Kelvin waves; in contrast, it is similar to the continental shelf waves in the southern shelves. The results can be used to study the contribution of generated CTWs to the transport of sediment and biological materials in all large lakes.  相似文献   
3.
南海北部陆坡区域构造地质控制着气源、流体疏导体系、富集空间及储层物性特征,因此,东沙海域、神狐海域、西沙海槽和琼东南盆地的水合物成藏条件及控制因素具有明显差异性。东沙海域深部气体可沿断层、裂缝、不整合面、砂岩疏导层和气烟囱等通道向上运移,并形成天然气水合物,具有渗漏型水合物产出特征;神狐海域水合物成藏与规模巨大的泥底辟活动相关,并与布莱克海台天然气水合物产出特征具有相似性;琼东南盆地中央坳陷带内为天然气水合物发育的重点区,底辟、泥火山或麻坑构造与天然气水合物发育密切相关。  相似文献   
4.
Web-based decision support tools (DSTs) can be useful to facilitate decision-making processes for managing complex natural resource systems. However, the alignment of DSTs with the objectives in governmental policies or management plans and the influence of limited local data on the outputs of these tools may reduce the use of DSTs by decision makers. In this study, we examined the outcomes of web-based DSTs when different types of local data were incorporated and demonstrated a way to incorporate outputs from multiple DSTs or local inventories to benefit barrier removal decisions. Restoring habitat connectivity in rivers in northwest lower Michigan, USA, was used as a case study due to the abundance of local inventory data and web-based DSTs. We found that, when compared to prioritizations made using local data, some DSTs could produce similar outcomes (in barriers selected, cost, and the benefit for migratory fish) with limited data, but the trade-offs among users' objectives might influence the cost and effectiveness of DSTs' outputs. Improving the ability of DSTs to incorporate objectives consistent with policy and stakeholders' values (e.g., restore certain species or sedimentation control) across management scales can help close the gap between tool recommendations and management decisions while making the barrier removal prioritization process transparent and efficient.  相似文献   
5.
The microstructure of the oral cavity and alimentary canal of herbivorous fish Siganus rivulatus collected from the Red Sea were investigated by using scanning electron microscope (SEM). The results showed that S. rivulatus has three types of teeth, tri‐cusped, bi‐cusped, and papilliform. A taste bud (Type I) was recorded in the oropharyngeal cavity. Characteristic styles of microridges on the cell's surface inside the buccal cavity were recorded. Also, the distribution of the mucous cells in the lining of the mouth cavity, alimentary canal was observed. Mucosal folds along the distinct parts of alimentary canal, showed characteristic pattern which was complex in the intestinal mucosa. The results concluded that there are characteristic microstructures according to feeding habitat compared with other bony fishes.  相似文献   
6.
Evidence suggests that diets rich in antioxidants reduce the risk factors of Alzheimer’s disease (AD). Hippophae rhamnoides, commonly known as sea buckthorn (SB), is rich in antioxidants which could have direct effects on amyloid-beta (Aβ) levels and consequently influence AD pathogenesis. In this study, sea buckthorn powder (SBP) was administered at varying concentrations (0.6, 0.9, 1.2, 1.5 and 1.8 µg mL−1) to cell cultures (BE(2)-M17) with 20 mm Aβ for 72 h. MTS test indicated that SB significantly increased cell viability in Aβ-induced cells up to 95%. Results of Western blot showed maximum 38% inhibition of Aβ compared to the control (Aβ only). ELISA demonstrated significantly lower amyloid-β level (6672 pg mL−1) than the control (10189 pg mL−1). Images of AFM further confirmed the presence of low quantity of amyloid beta in SBP-treated cells. These findings suggest that SB warrants further investigation as potential therapeutic agent in the treatment of AD.  相似文献   
7.
在南海某珊瑚岛礁的工程勘察中,采用快速高效的浅层水域地震反射波勘探方法配合钻探进行联合勘察,将钻孔的“点”与物探的“线”结合起来,相互对比、佐证,进行综合解释,查明了岛礁珊瑚松散沉积物的厚度、基岩起伏形态及大范围内的连续地质剖面。勘探结果为岛礁岩土工程性状调查、水文地质调查以及工程建设提供了可靠的地质依据和设计参数,取得了理想的效果。水域地震反射波对岛礁的不同地貌单元内礁坪、向海坡、潟湖、外海的沉积层界面反映清晰,但在外礁坪区域由于现代海滩岩的发育,声波较难穿透。  相似文献   
8.
S型走滑转换带是走滑环境下广泛发育的一类构造。以往的研究认识多集中在对走滑转换带类型划分的探讨上,缺乏对其控藏作用的精细研究。本次研究利用渤海海域辽东湾地区连片三维地震资料,结合油气田实例,运用统计学方法分析了辽西构造带S型走滑转换带的控藏作用。辽西带新生代构造变形总体表现为NE向伸展构造系统和NNE向右旋走滑构造系统的叠加构造变形,S型走滑转换带可分为增压段和释压段两大类。按照走滑转换带演化阶段的不同,将增压段进一步细分为压扭低凸起段、平缓增压段和强烈增压段等3个亚类。将释压段同样细分为纺锤形浅凹、平缓释压段和菱形释压段等3个亚类。将走滑断裂末端发育的转换带归纳为增压型或释压型马尾扇。应用S型走滑转换带“油气富集指数”的分析方法,论证了S型走滑转换带弯曲度与走滑调节断层活动性具有正相关性,并成功应用于辽西凹陷南次洼旅大5-2北油田成藏分析工作中,为勘探决策提供了定量化依据。  相似文献   
9.
Abstract

The formation of underwater adhesion is a complicated physiological process and many different types of enzymes are found to be essential apart from structural proteins. Previous studies have shown that various tyrosinases were present in marine adhesives, but little information is available about the over-expression and enzymatic characterization of these enzymes. Specifically, this study first identified four significantly up-regulated tyrosinases in the pedal disc of Haliplanella luciae by means of multi-omics technology, and made preliminary bioinformatics predictions. Sequence alignment showed that the Tyr1_Hl contained six conserved His residues that bind to copper ions, of which a tyrosinase with diphenolase activity named as Tyr1_HlΔ, was expressed in Escherichia coli BL21 (DE3) cells and purified by affinity chromatography. Enzymatic characterization showed that the activity of Tyr1_HlΔ was Cu2+ dependent and maximum catalytic activities were in 20?mM Tris–HCl (pH 8.0) at 37?°C. In summary, we identified novel tyrosinases in the pedal disks of sea anemone for the first time and the Tyr1_HlΔ was successfully recombinant expressed. Our study will provide basis for future exploration of bio-adhesion mechanism and design of bio-adhesives derived from sea anemones.  相似文献   
10.
This study investigated mercury contamination levels in eight commercially valuable crustacean species caught off the Central Adriatic and Tyrrhenian coasts of Italy. Total mercury levels were measured by Thermal Decomposition-Amalgamation-Atomic Absorption Spectrophotometry. Results showed a high variability among species with values ranging from 0.070 to 1.24 (mg kg?1 wet weight). The lowest mercury levels were detected in caramote prawn (Penaeus kerathurus), warty crab (Eriphia verrucosa) and European spider crab (Maja squinado), decapods living in shallow waters. Levels exceeding the limits established by the European Commission were found in species living in close contact with bottom sediments: deepwater rose shrimp (Parapenaeus longirostris), blue and red shrimp (Aristeus antennatus) and Norway lobster (Nephrops norvegicus). For shrimps, the inter-individual variability observed was mostly related to the body size, indicating the accumulation of mercury with age. An estimation of the human intake of mercury associated to the consumption of the crustaceans sampled and its comparison with the Tolerable Weekly Intake are provided.  相似文献   
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