Natural conditions

自然条件
  • 文章类型: Journal Article
    湿地土壤中的微生物群落对维持湿地生态系统的稳定至关重要。然而,湿地土壤微生物群落对环境胁迫敏感。这导致微生物群落结构可能受到环境因素的影响。为深入了解不同环境因子对湿地土壤微生物群落结构的响应,这篇综述全面探讨了自然条件的因素(例如,不同类型的湿地,土壤理化性质,气候条件),生物因素(例如,植物,土壤动物),和人类活动(例如,土地利用,土壤污染,放牧)。这些因素可以通过不同的方式影响湿地土壤中的微生物群落结构和活动,例如(i)影响土壤微生物存活的湿地土壤环境,(ii)影响可用营养素(例如,碳,氮)微生物活性所需,和(iii)对土壤微生物的直接影响(抗性物种的毒性或促进)。本综述可为湿地土壤微生物多样性的保护提供参考。维持湿地生态系统的平衡,和湿地生态恢复。
    Microbial community in wetland soils is crucial for maintaining the stability of the wetland ecosystem. Nevertheless, the soil microbial community is sensitive to the environmental stress in wetlands. This leads to the possibility that the microbial community structure may be influenced by environmental factors. To gain an in-depth understanding in the response of microbial community structure in wetland soils under different environmental factors, this review comprehensively explores the factors of natural conditions (e.g., different types of wetland, soil physical and chemical properties, climate conditions), biological factors (e.g., plants, soil animals), and human activities (e.g., land use, soil pollution, grazing). Those factors can affect microbial community structure and activities in wetland soils through different ways such as (i) affecting the wetland soil environment in which soil microorganisms survived in, (ii) influencing the available nutrients (e.g., carbon, nitrogen) required for microbial activity, and (iii) the direct effects on soil microorganisms (toxicity or promotion of resistant species). This review can provide references for the conservation of microbial diversity in wetland soils, the maintenance of wetland ecosystem balance, and the wetland ecological restoration.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

    求助全文

  • 文章类型: Journal Article
    Irishymenospatha和Irishistrio的本地人口,虹膜科大虹膜属中的两个濒危球茎物种,由于中亚自然栖息地的采矿和其他工业活动而面临灭绝的威胁,包括伊朗。这些物种由于其多功能性和有吸引力的表型特征,不仅对全球园艺业产生重大的经济影响,但也具有重要的生态价值,需要对其进行保护。在这项研究中,我们检查了这两个物种中个体之间的形态和功能多样性,对环境压力表现出高耐受性。我们的研究基于球茎检查了10个I.hymenospatha种群和两个I.histrio种群,花,和整个伊朗的叶子特征。我们认识到I.hymenospatha种群中五种不同叶片形状的分级,某些种群之间存在显着差异,包括“Arak-Khomain”和“Arak-Gerdo”。\"Jaro\",“纳坦兹-卡尔卡斯”,\"Ardestan-Taleghan\",\"Arak-Rahjerd\",\"Arak-Gerdo\",\"Ganjnameh\",和“Abas-Abad”I.hymenospatha的种群显示出叶片宽度的最大值,花下的茎直径,冠部直径,花数,叶数,和灯泡直径。I.histrio“Velian”种群的花朵尺寸明显更大,更长的茎长度,更大的样式宽度,更长的开花日期,与I.Histrio的“Ganjnameh”种群相比,植物高度更高。这两个物种的这种特征使它们成为非凡的观赏植物。我们的研究还表明,I.hymenospatha种群生长在不同的土壤和海拔上,并具有适应不同生长条件的能力。鉴于他们面临的威胁,通过园艺选择和繁殖进行保护为这两个物种提供了可行的保护策略。这种方法不仅保留了这些物种的遗传多样性,而且也使他们对园艺业的进一步贡献。
    The native populations of Iris hymenospatha and Iris histrio, two endangered bulbous species within the large Iris genus in Iridaceae, are threatened with extinction due to mining and other industrial activities in their natural habitats in Central Asia, including Iran. These species not only have a significant economic impact on the global horticultural industry due to their versatility and attractive phenotypic traits, but also have significant ecological value that necessitates their conservation. In this study, we examined the morphological and functional diversity between individuals within these two species, which exhibit high tolerance to environmental stresses. Our study examined 10 populations of I. hymenospatha and two populations of I. histrio based on bulb, flower, and leaf characteristics throughout Iran. We recognized a gradation of five different leaf shapes among I. hymenospatha populations with significant differences between some populations, including \"Arak-Khomain\" and \"Arak-Gerdo\". The \"Jaro\", \"Natanz-Karkas\", \"Ardestan-Taleghan\", \"Arak-Rahjerd\", \"Arak-Gerdo\", \"Ganjnameh\", and \"Abas-Abad\" populations of I. hymenospatha displayed maximal values in leaf width, stem diameter under flower, crown diameter, flower number, leaf number, and bulb diameter. The I. histrio \"Velian\" population had a significantly larger flower size, a longer stem length, a larger style width, a longer flowering date, and a higher plant height compared to the \"Ganjnameh\" population of I. histrio. Such characteristics of both species make them remarkable ornamental plants. Our study also revealed that I. hymenospatha populations grow on different soils and elevations and have the ability to adapt to different growing conditions. Given the threats they face, conservation through horticultural selection and propagation offers a viable conservation strategy for both species. This approach not only preserves the genetic diversity of these species, but also enables their further contribution to the horticultural industry.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

       PDF(Pubmed)

  • 文章类型: Journal Article
    用于构建光电器件的有源部分的材料的老化动力学是当前感兴趣的主题。我们研究了掺杂有Ge和Sn的GaAs的外延样品,最高可达1×1019cm-3,这些样品在干燥和黑暗的环境中保存了26年。光致发光光谱在三个时期进行:1995年、2001年和2021年。在去年,时间分辨光致发光,拉曼,还进行了X射线测量,以研究样品中O2作用形成的缺陷的演变及其与Ge和Sn杂质掺杂的相关性。我们发现氧形成的氧化物会释放出Ga和As原子,留下的空缺主要是As。这些空位与掺杂剂杂质形成络合物。在这26年中,空缺的浓度可能高达1×1018cm-3。
    The aging dynamics of materials used to build the active part of optoelectronic devices is a topic of current interest. We studied epitaxial samples of GaAs doped with Ge and Sn up to 1×1019 cm-3, which were stored in a dry and dark environment for 26 years. Photoluminescence spectra were taken in three periods: 1995, 2001 and 2021. In the last year, time-resolved photoluminescence, Raman, and X-ray measurements were also performed to study the evolution of defects formed by the action of O2 in the samples and its correlation with the doping with Ge and Sn impurities. We found that oxygen formed oxides that gave off Ga and As atoms, leaving vacancies mainly of As. These vacancies formed complexes with the dopant impurities. The concentration of vacancies over the 26 years could be as large as 1×1018 cm-3.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

       PDF(Pubmed)

  • 文章类型: Journal Article
    目的:在一项研究中,研究了马牙裂牙吸收和缺氧症(EOTRH),冰岛的老年马在其原籍国进行了检查。这项调查的主题是牙科治疗以及保持和喂养管理对头端口腔健康的影响。
    方法:位于西北不同地区的170匹马(年龄≥15岁),西,冰岛南部。
    方法:马主填写了一份关于饲养的问卷,喂养,和预防性牙科护理。对马进行了临床检查,特别注意了口腔的牙龈和牙齿疾病,如牙龈炎,瘘管,牙龈回缩,牙根和牙结石的扩大以及门牙的完整性,咬合角度,和牙齿的流动性。
    结果:大多数马整年都在牧场上饲养,几乎没有补充饲料。冰岛的牙科治疗频率很低。只有几匹马受到牙齿脱落的影响,牙龈炎,牙龈衰退,和门牙微积分.与门牙相比,犬科动物的结石发生频率更高,更严重。研究结果并不取决于马的位置。
    结论:假设冰岛老年马头端口腔的显着健康不是由预防性牙科护理引起的,这很可能是由于冰岛的生活条件。连续性,咀嚼的强度,即使在老年马匹中,牧草的本土性也可能促进门牙和牙齿周围组织的健康。
    In the context of a study of Equine Odontoclastic Tooth Resorption and Hypercementosis (EOTRH), elderly Icelandic horses were examined in their originating country. The subject of this survey was the impact of dental treatment and keeping and feeding management on the health of the rostral oral cavity.
    A total of 170 horses (aged ≥ 15) located in different areas of Northwest, West, and South Iceland.
    The horse owners completed a questionnaire about keeping, feeding, and preventative dental care. The horses were clinically examined with particular attention to gingival and dental disorders of the rostral mouth, such as gingivitis, fistula, gingiva retraction, enlargement of the roots and dental calculus as well as integrity of incisors, bite angle, and tooth mobility.
    Most of the horses were kept on pasture all year with little supplementary feeding. The frequency of dental treatment in Iceland was low. Only a few horses were affected by tooth loss, gingivitis, gingival recession, and incisor calculus. Calculus occurred more frequently and more severely in canines than in incisors. The findings did not depend on the location of the horse.
    Assuming that the remarkable health of the rostral oral cavity in elderly Icelandic horses was not caused by preventive dental care, it is likely that it was due to living conditions in Iceland. Continuity, intensity of chewing, and nativeness of forage might promote the health of incisors and tissue surrounding the tooth even in elderly horses.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

    求助全文

  • 文章类型: Journal Article
    在本研究中,我们使用非靶向代谢组学分析,从自然种群(Ruhama:R和She\'arYashuv:S)和实验室饲养的菌落(C)中检查了黑兵蝇(BSF)幼虫的代谢组成。结果表明,苯丙氨酸和嘌呤代谢的代谢产物以及苯丙氨酸的生物合成显著过度积累,酪氨酸和色氨酸,和精氨酸在两个自然种群中,和丰富的途径分析,与实验室饲养的菌落相比。此外,我们发现谷胱甘肽代谢和氨酰tRNA生物合成相关代谢产物的积累,以及亚油酸和色氨酸代谢相关的代谢产物。此外,我们发现丙氨酸代谢产物的积累减少,天门冬氨酸和谷氨酸代谢在两个自然群体:氨基糖和核苷酸糖代谢仅在R群体和氨酰基-tRNA生物合成,乙醛酸和二羧酸仅在S群体中代谢。总的来说,结果表明,自然生长的幼虫需要大量来自芳香族氨基酸(苯丙氨酸,酪氨酸和色氨酸)用于在自然条件下防御病原体,例如,黑色素化。此外,谷胱甘肽代谢物帮助BSF在氧化应激下存活。对自然生长和实验室饲养的幼虫的功能代谢组学的进一步研究可以为更好地理解BSF幼虫在复杂环境中的生存机制提供平台。
    In the present study, we examined the metabolic composition of black soldier fly (BSF) larvae from natural populations (Ruhama: R and She\'ar Yashuv: S) and from a laboratory-reared colony (C) using untargeted metabolomics analysis. The results revealed significant over-accumulation of metabolites from phenylalanine and purine metabolism and biosynthesis of phenylalanine, tyrosine and tryptophan, and arginine in both natural populations, and enriched pathway analysis, compared to the laboratory-reared colony. In addition, we found accumulation of glutathione metabolism and aminoacyl tRNA biosynthesis related metabolites in R, and linoleic acid and tryptophan metabolism related metabolites in S. Moreover, we found down-accumulation of metabolites belonging to alanine, aspartate and glutamate metabolism in both natural populations: amino sugar and nucleotide sugar metabolism only in the R population and aminoacyl-tRNA biosynthesis, glyoxylate and dicarboxylate metabolism only in the S population. Overall, the results suggest that the naturally growing larvae require large quantities of metabolites from aromatic amino acids (phenylalanine, tyrosine and tryptophan) for defense against pathogens under natural conditions e.g., melanization. In addition, glutathione metabolites help the BSF to survive under oxidative stress. Further study of the functional metabolomics of naturally growing and laboratory-reared larvae could provide a platform for better understanding of BSF larval survival mechanisms in complex environments.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

    求助全文

  • 文章类型: Journal Article
    强力霉素是水产养殖中治疗鱼类疾病的重要药物。然而,它的过量使用导致残留物超过威胁人类健康。所以,这项研究旨在基于统计方法估计小龙虾(Procambarusclarkii)中多西环素(DC)的可靠戒断时间(WT),并对自然环境中的人类健康进行风险评估.在预定时间点收集样品并通过高效液相色谱法测定。使用一种新的统计方法处理残留浓度数据。回归数据线的均匀性和线性度由Bartlett评估,Cochran\'s,F测试通过在正态概率量表上建立标准化残差与它们的累积频率分布来排除异常值。根据中国和欧洲的规定,计算的小龙虾肌肉中的WT为43天。43天后,估计DC日摄入量为0.022-0.052µg/kg/d.危险系数在0.007到0.014之间,远小于1。这些结果表明,建立的WT可以避免小龙虾中DC残留对人类的健康风险。
    Doxycycline is an important medicine in aquaculture for treating fish diseases. However, its excess use causes residue exceeding to threaten human health. So, this study aimed to estimate a reliable withdrawal time (WT) of doxycycline (DC) in crayfish (Procambarus clarkii) based on statistical approaches and conduct a risk assessment for human health in the natural environment. Samples were collected at predetermined time points and determined by high-performance liquid chromatography. A novel statistical method was used to process the data of residue concentration. The homogeneity and linearity of the regressed line of data were evaluated by Bartlett\'s, Cochran\'s, and F tests. Outliers were excluded by establishing the standardized residual versus their cumulative frequency distribution on a normal probability scale. The calculated WT was 43 days in muscle of crayfish based on China and European stipulations. After 43 days, estimated daily intakes of DC were ranged from 0.022 to 0.052 µg/kg/d. Hazard Quotients were ranged from 0.007 to 0.014, which were far less than 1. These results indicated that established WT could avoid health risks for humans resulting from DC\'s residue in crayfish.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

    求助全文

  • 文章类型: Journal Article
    研究了自然条件下生物基塑料材料在田间土壤中的降解。三种生物基塑料材料,其中含有聚丙交酯(PLA)与聚己二酸丁二醇酯和添加剂(PLA_1),PLA基聚酯与矿物填料的共混物(PLA_2),和聚丁二酸丁二醇酯与矿物填料(PBS_1)在薄膜的形式,经历了土壤埋藏的生物降解过程。实验是在年平均温度为9.4°C的气候下进行的,冬季和夏季为一年。通过宏观和微观观察评估材料的降解,减肥,热重分析,和拉伸试验。宏观观察表明,样品PBS_1降解12个月后,膜表面颜色的变化可见。使用显微镜检查观察12个月后表面样品PLA_1和PBS_1的侵蚀。降解一年后样品PLA_1和PLA_2的质量损失均低于0.6%。此外,对于PBS_1样品,质量损失等于4.3%。根据获得的质量损失结果,提出了降解动力学的描述,显示测试聚合物的厚度随时间的变化。在降解过程中,PLA_1和PLA_2的热稳定性降低了16.1和2.6°C,分别,对于PBS_1,增加了1.7°C。降解12个月后,样品PLA_1和PLA_2的断裂拉伸强度下降了27.3%和5.8%,分别,与未暴露样品相比,样品PBS_1增加了28.2%。
    The degradation of bio-based plastic materials in field soil under natural conditions was investigated in this study. Three bio-based plastics materials, which contained polylactide (PLA) with polybutylene adipate terephthalate and additives (PLA_1), PLA-based polyester blend with mineral filler (PLA_2), and polybutylene succinate with mineral filler (PBS_1) in the form of the film, were subjected to soil burial biodegradation processes. The experiments were carried out in a climate with an average annual temperature of 9.4 °C, in winter and summer periods for one year. The degradation of the materials was evaluated by macro- and microscopic observations, weight loss, thermogravimetric analysis, and tensile test. Macroscopic observation indicated that changes in the color of film surface were visible for samples PBS_1 after 12 months of degradation. Using microscopic inspection the erosion of surface samples PLA_1 and PBS_1 after 12 months was observed. Mass loss of samples PLA_1 and PLA_2 after one year of degradation were below 0.6 %. Moreover, for PBS_1 sample, mass loss was equal to 4.3 %. Based on the obtained results of the mass loss, a description of the degradation kinetics was proposed, showing the changes in the thickness of the tested polymer over time. The thermal stability of the samples PLA_1 and PLA_2 decreased during the degradation process by 16.1 and 2.6 °C, respectively, and for PBS_1 increased by 1.7 °C. Tensile strength at break after 12 months of degradation decreased for sample PLA_1 and PLA_2 by 27.3 and 5.8 %, respectively, and increased for sample PBS_1 by 28.2 % compare to unexposed sample.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

    求助全文

  • 文章类型: Journal Article
    非颤抖产热(NST)是允许哺乳动物控制其体温的关键机制。性别经常会影响体温调节要求;因此,男性和女性的NST能力可能会有很大差异。已经在实验动物和人类中描述了NST的几种与性别相关的差异;然而,这些参数在自然条件下生活的动物中研究相对较少。这里,我简要回顾了可能导致这种差异的因素,并指出了在自然条件下寻找NST性别差异时特别有希望的两种情况:哺乳期和遗传多态性物种中NST控制的潜在线粒体冲突。
    Nonshivering thermogenesis (NST) is a key mechanism that allows mammals to control their body temperature. Sex can frequently affect thermoregulatory requirements; therefore, males and females can be expected to differ significantly in their NST capacity. Several sex-related differences in NST have been described in laboratory animals and humans; however, these parameters are relatively rarely studied in animals living under natural conditions. Here, I briefly review factors that may be responsible for this disparity and point out two situations that should be particularly promising in searching for sex differences in NST under natural conditions: the lactation period and potential mitonuclear conflicts over NST control in species with genetic polymorphism.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

       PDF(Sci-hub)

  • 文章类型: Journal Article
    将行为活动调整到一天中的正确时间的适应性意义似乎显而易见。实验室研究暗示昼夜节律在行为定时和节律中的重要作用。然而,最近对时钟突变动物的研究在更自然的环境下质疑这种重要性,由于各种时钟突变体在半自然zeitgeber条件下显示出几乎正常的diel活动节奏。我们在这里报告证据表明,果蝇的重要行为,在准自然条件下需要一个功能性的分子钟.与野生型苍蝇相比,具有分子钟缺陷的周期性01突变体在温带环境中显示出节律性和门控性受损,即使存在完整的非生物时代特征。尽管period01突变体仍然在白天的某个时间窗口内关闭,这个时间窗口更广泛,定义松散,根据各种统计指标的分类,节律性降低或丧失。此外,峰值熄灭时间变得更容易受到光照变化的日常变化的影响。相比之下,肽能时钟间信号传导受损的果蝇(Pdf01和han5304PDF受体突变体)大多有节奏地闭合,门大小正常,类似于野生型对照。我们的结果表明,自然时代精神的存在是不够的,并且需要功能性分子钟来在温带条件下在果蝇中诱导稳定的时间羽化模式,并且光强和温度每天都在变化。温和的时代周刊,然而,足以在功能上挽救PDF介导的时钟内部和输出信号的损失。
    The adaptive significance of adjusting behavioral activities to the right time of the day seems obvious. Laboratory studies implicated an important role of circadian clocks in behavioral timing and rhythmicity. Yet, recent studies on clock-mutant animals questioned this importance under more naturalistic settings, as various clock mutants showed nearly normal diel activity rhythms under seminatural zeitgeber conditions. We here report evidence that proper timing of eclosion, a vital behavior of the fruit fly Drosophila melanogaster, requires a functional molecular clock under quasi-natural conditions. In contrast to wild-type flies, period01 mutants with a defective molecular clock showed impaired rhythmicity and gating in a temperate environment even in the presence of a full complement of abiotic zeitgebers. Although period01 mutants still eclosed during a certain time window during the day, this time window was much broader and loosely defined, and rhythmicity was lower or lost as classified by various statistical measures. Moreover, peak eclosion time became more susceptible to variable day-to-day changes of light. In contrast, flies with impaired peptidergic interclock signaling (Pdf01 and han5304 PDF receptor mutants) eclosed mostly rhythmically with normal gate sizes, similar to wild-type controls. Our results suggest that the presence of natural zeitgebers is not sufficient, and a functional molecular clock is required to induce stable temporal eclosion patterns in flies under temperate conditions with considerable day-to-day variation in light intensity and temperature. Temperate zeitgebers are, however, sufficient to functionally rescue a loss of PDF-mediated clock-internal and -output signaling.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

       PDF(Sci-hub)

       PDF(Pubmed)

  • 文章类型: Journal Article
    微粒污染目前被认为是一个严重的环境问题,这与空气质量下降和人类健康密切相关,以及全球气候变化。
    准确识别导致空气污染的关键因素具有重要意义。在现有文献中很少考虑这些因素的时间和空间异质性。
    在这项研究中,我们采用地理和时间加权回归模型(GTWR),探讨了1998年至2015年期间,自然条件和社会经济问题对中国287个城市PM2.5污染发生的影响方向和强度。
    发现PM2.5污染严重的城市主要位于中国北方,而污染较少的城市被证明位于中国南方。较高的温度和风速被发现能够缓解该国东南部的空气污染,在那里,降水增加也被证明可以降低PM2.5浓度;而在南部、中部和西部地区,降水量与PM2.5浓度呈正相关。发现相对湿度增加会增强中国西南和东北地区的PM2.5浓度。此外,人均GDP和人口密度被证明会加剧中国西北地区的PM2.5浓度,相反,它们对其他地区的PM2.5浓度水平产生了重大不利影响。与中国其他城市相比,东南部城市的城市建成区面积与PM2.5浓度水平呈正相关。
    PM2.5浓度在中国表现出一系列阶段的差异,表现出明显的空间差异。PM2.5浓度水平与其决定因素之间的关联表现出明显的空间异质性。本文的研究结果为区域制定有针对性的减排政策提供了详细的支持。
    Particulate pollution is currently regarded as a severe environmental problem, which is intimately linked to reductions in air quality and human health, as well as global climate change.
    Accurately identifying the key factors that drive air pollution is of great significance. The temporal and spatial heterogeneity of such factors is seldom taken into account in the existing literature.
    In this study, we adopted a geographically and temporally weighted regression model (GTWR) to explore the direction and strength of the influences of natural conditions and socioeconomic issues on the occurrence of PM2.5 pollutions in 287 Chinese cities covering the period 1998 to 2015.
    Cities with serious PM2.5 pollution were discovered to mainly be situated in northern China, whilst cities with less pollution were shown to be located in southern China. Higher temperature and wind speed were found to be able to alleviate air pollution in the country\'s southeast, where enhanced precipitation was also shown to reduce PM2.5 concentrations; whilst in southern and central and western regions, precipitation and PM2.5 concentrations were positively correlated. Increased relative humidity was found to reinforce PM2.5 concentration in southwest and northeast China. Furthermore, per capita GDP and population density were shown to intensify PM2.5 concentrations in northwest China, inversely, they imposed a substantial adverse effect on PM2.5 concentration levels in other areas. The amount of urban built-up area was more positively associated with PM2.5 concentration levels in southeastern cities than in other cities in China.
    PM2.5 concentrations conformed to a series of stages and demonstrated distinct spatial differences in China. The associations between PM2.5 concentration levels and their determinants exhibit obvious spatial heterogeneity. The findings of this paper provide detailed support for regions to formulate targeted emission mitigation policies.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

       PDF(Sci-hub)

公众号