不同林龄和密度对马尾松人工林凋落叶养分变化的影响

该文选择广西南宁市横县镇龙林场的4种林龄(幼龄林、中龄林、成熟林和过熟林)和4种密度(低密度林、中低密度林、中高密度林和高密度林)马尾松人工林共8种林分作为研究对象,分析了未破碎和破碎两个不同降解阶段的凋落叶C、N、P含量及其生态化学计量学特征。结果表明:(1)不同林龄中,凋落叶初始C、N含量在过熟林和成熟林中较高,P含量没有显著变化,且C∶N比值和C∶P比值从幼龄林到成熟林逐渐升高,说明较高林龄马尾松对N和P重吸收较低,而较低林龄马尾松对N和P重吸收较强,需要较大。(2)不同密度林中,随着林木密度的增加,凋落叶初始C含量逐渐升高,N含量无显著变化,P含量降低;高密度林凋落叶的初始C∶P比值和N∶P比值较高,说明高种植密度下马尾松可能对N和P养分的需求较大,P重吸收较强。(3)不同林龄和不同密度马尾松林的破碎凋落叶C含量、C∶N比值、C∶P比值和N∶P比值比未破碎凋落叶的低,N和P含量较高,说明凋落物在降解过程中出现N和P养分的富集现象。(4)中林龄和较高种植密度的马尾松破碎凋落叶与未破碎凋落物的C含量差值最大,C∶N比值和C∶P比值较低,说明这两种林分的凋落叶C的降解速率可能较大。上...     

黄土丘陵区人工柠条种植年限和坡位对土壤团聚体稳定性的影响

柠条(Caragana korshinskii Kom.)种植是黄土高原地区生态环境建设中重要的人工植被恢复措施。选择黄土丘陵区条带种植15、25和35年的柠条坡地,以荒草坡地为对照,运用Le Bissonnais法分析柠条种植不同年限和坡位对0—40 cm土层团聚体分布及其稳定性的影响。结果表明:长时间柠条种植对土壤团聚体稳定性的影响主要在0—20 cm土层;不同处理下土壤大团聚体(>0.25 mm)含量总体表现为柠条35年>柠条25年>柠条15年>荒草地,表明柠条种植年限增加促进了大团聚体的形成。从坡面尺度看,柠条平均重量直径整体表现为坡下>坡上>坡中;在上坡的柠条35年样地具有最大值(3.08 mm),但在下坡荒草地显著高于柠条林地(P<0.05)。基于相对消散指数和相对机械破碎指数,上中坡土壤团聚体均对消散作用和机械破碎作用较敏感,而下坡的下层土壤团聚体对破碎作用更敏感。冗余分析表明,土壤有机碳和粘粒含量与柠条平均重量直径呈显著正相关关系(P<0.05)。种植年限是影响土壤团聚体稳定性的主要因素,解释了30.4%的变异;其次是土层...     

A cost-effective blood DNA methylation-based age estimation method in domestic cats,Tsushima leopard cats (Prionailurus bengalensis euptilurus) and Panthera species,using targeted bisulphite sequencing and machine learning models

Individual age can be used to design more efficient and suitable management plans in both in situ and ex situ conservation programmes for targeted wildlife species. DNA methylation is a promising marker of epigenetic ageing that can accurately estimate age from small amounts of biological material, which can be collected in a minimally invasive manner. In this study, we sequenced five targeted genetic regions and used 8–23 selected CpG sites to build age estimation models using machine learning methods at only about $3–7 per sample. Blood samples of seven Felidae species were used, ranging from small to big, and domestic to endangered species: domestic cats (Felis catus, 139 samples), Tsushima leopard cats (Prionailurus bengalensis euptilurus, 84 samples) and five Panthera species (96 samples). The models achieved satisfactory accuracy, with the mean absolute error of the most accurate models recorded at 1.966, 1.348 and 1.552 years in domestic cats, Tsushima leopard cats and Panthera spp. respectively. We developed the models in domestic cats and Tsushima leopard cats, which were applicable to individuals regardless of health conditions; therefore, these models are applicable to samples collected from individuals with diverse characteristics, which is often the case in conservation. We also showed the possibility of developing universal age estimation models for the five Panthera spp. using only two of the five genetic regions. We do not recommend building a common age estimation model for all the target species using our markers, because of the degraded performance of models that included all species.     

育龄期妇女阴道微生态平衡与宫颈息肉的相关性

观察育龄期妇女阴道微生态平衡与宫颈息肉的相关性, 旨在为宫颈息肉的预防提供参考意见。

回顾性分析广西医科大学附属武鸣医院2019年1月至2020年12月收治89例宫颈息肉患者资料纳入宫颈息肉组; 回顾性分析广西医科大学附属武鸣医院同期91例健康体检育龄期妇女的临床资料纳入对照组。记录2组研究对象阴道微生态指标, 分析育龄期妇女阴道微生态平衡与宫颈息肉的关系, 并检验阴道微生态指标对宫颈息肉发生风险的评估价值。

初步比较宫颈息肉组、对照组研究对象阴道微生态指标后, 经回归分析检验结果显示, 育龄期妇女白细胞酯酶(LE)、唾液酸苷酶(SNA)、乙酰氨基葡萄糖苷酶(NAG)、清洁度、上皮细胞、白细胞、线索细胞、短杆菌及阴道微生态菌群异常与宫颈息肉的发生有关(OR=2.587、4.404、3.164、41.250、3.312、9.796、5.312、6.789、5.372, P=0.002、＜0.001、0.005、＜0.001、＜0.001、＜0.001、0.001、＜0.001、0.033);Kendall′s W相关性分析检验结果显示, 育龄期妇女LE、SNA、NAG、清洁度、上皮细胞、白细胞、线索细胞、短杆菌及阴道微生态菌群异常状况均与宫颈息肉发生呈正相关(r=0.333、0.278、0.316、0.449、0.389、0.424、0.357、0.373、0.331, 均P＜0.001);绘制受试者工作曲线(ROC), 育龄期妇女LE、SNA、NAG、清洁度、上皮细胞、白细胞、线索细胞、短杆菌及阴道微生态菌群异常情况用于评估宫颈息肉发生的曲线下面积(AUC)分别为0.617、0.613、0.586、0.715、0.644、0.686、0.591、0.664和0.566, 其中清洁度对宫颈息肉发生有中等评估价值, AUC＞0.70。

育龄期妇女阴道微生态平衡与宫颈息肉发生密切相关, LE、SNA、NAG、清洁度、上皮细胞、白细胞、线索细胞、短杆菌及阴道微生态菌群异常均与宫颈息肉发生有关, 其中清洁度可用于评估宫颈息肉的发生, 临床可根据患者阴道微生态平衡状况, 制定针对性措施。

     

西藏日喀则恰布林剖面大竹卡组孢粉组合及其时代和古环境、古地理意义

西藏日喀则沿雅鲁藏布江分布的大竹卡组为一套杂色的砂砾岩沉积.与新生代印度-劳亚板块的碰撞和青藏高原的隆升具有密切的联系.迄今为止,其中尚未有可靠的化石发现用于指示时代.当前研究根据从大竹卡组中的一些粉、细砂岩中获得的较丰富的孢粉化石,首次探讨其沉积时期的古植物区系和陆地生态环境特征.孢粉组合以榆科和胡桃科具孔类和壳斗科三(拟孔)沟类被子植物花粉占优势,也见有较多的蕨类植物孢子和裸子植物两气囊花粉,其时代可能是渐新世-早中新世.孢粉组合反映大竹卡组沉积期间恰布林一带的气候比较温暖、湿润,揭示印度、劳亚大陆碰撞早期的热带-南亚热带低山丘陵环境.植物区系横向对比表明,恰布林自始新世末以来向北位移了大约500km.     

Multi-scale habitat selection by Murray cod Maccullochella peelii peelii in two lowland rivers

This study provides information on habitat selection by the threatened Murray cod Maccullochella peelii peelii at two spatial scales in the Ovens and Murray Rivers in south-eastern Australia. Both adult (>450 mm total length, L _T) and age 0 year (<150 mm L _T) M. p. peelii selected macro and microhabitats based on structural variables. At the macrohabitat scale, adults selected channel habitats in the river, floodplain channels at high floods and within Lake Mulwala, whereas the floodplain proper was avoided. Adult and age 0 year fish selected similar microhabitats regardless of site or hydrologic conditions, and selection was primarily influenced by the presence of higher loadings of structural woody habitat, higher c.v. in depth, more overhanging vegetation, shallower comparative depths and lower water velocities, closer to the bank. Age 0 year M. p. peelii appeared to select shallower habitats with greater amounts of structural woody habitat, closer to the river bank than adult fish.     

Further evaluation of physical fitness age versus physiological age in women

The present study was conducted to examine further whether adult women who are in a state of high physical fitness possess high physiological functions, and also to investigate whether those who exercise regularly are able to maintain a high quality of various physiological functions. The subjects of this study were 249 healthy Japanese adult women (aged 20–70 years). Of these subjects 30 had jogged or walked regularly for more than 3 years. The physiological ages (PA) and physical fitness ages (FA) of the individuals were estimated from 17 physiological function tests and 5 physical fitness tests, respectively, by principal components analyses. The results indicated that there was a significant correlation between PA and FA (r = 0.76, P < 0.01). To examine this relationship in more detail, the subjects were classified into three physical fitness groups (high, normal and low) based on the deviation from the regression line of FA. Comparison of the mean PA among three physical fitness groups revealed that the high physical fitness groups demonstrated a much lower PA (physiologically younger), while the low physical fitness groups showed a relatively higher PA (physiologically older) in spite of their equivalent chronological ages. From this series of studies, a new concept is proposed where different individuals have different peak physiological capacities, but that these capacities change with age at similar rates. It is suggested that interventions such as exercise and a proper diet for promoting health could increase peak functional capacity but have little effect on the rate of decline. Accepted: 3 March 1998     

High abundance of an exotic amphipod indicates disturbance in tropical rainforests

Previous studies have proposed terrestrial amphipods as potential bioindicators of forest condition. In order to investigate the response of the exotic terrestrial amphipod Talitroides topitotum (Crustacea: Amphipoda: Talitridae) to anthropogenic disturbances and its potential as a bioindicator, we compared its abundance among three forest reserves in southeastern Brazil, under different types and intensities of disturbance. We observed significantly higher abundances in disturbed sites compared to undisturbed sites in two of the reserves sampled, corroborating previous studies. In the third reserve, in which both forest disturbance and the abundance of amphipods were much lower than in the other two reserves, there was no significant difference between the sampling sites. We also speculate about the potential use of terrestrial amphipods as global indicators of forest disturbance.     

Assessment of ecosystem services at the national level in Germany—Illustration of the concept and the development of indicators by way of the example wood provision

The EU Biodiversity Strategy stipulates in Target 2, Action 5 that the member states must map and assess the state of the ecosystems and their services and promote the integration into the reporting systems at the EU and national level by 2020. Therefore indicators for capturing and assessing ecosystem services (ES) are needed. In this paper we report for which ES class types currently ES indicators are being developed for Germany in the context of an ongoing research project. Additionally, we provide the indicator specifications, which are based on underlying framework concept. By way of the example of the provisioning service ‘raw wood production’ and the development of the main-indicator ‘annual wood accrual’ and six sub-indicators, we illustrate the concrete procedure, including discussion of results and target values. The indicators for the ES wood provision are not only suitable for an exemplary illustration of procedure, data selection and data basis in Germany. Furthermore, it shows that indicators for provisioning ES can eminently conflict with biodiversity and other ES.