濒危植物秦岭石蝴蝶的生态学特性及濒危原因分析

通过野外调查和随机取样法,对仅产于陕西勉县的中国特有濒危植物秦岭石蝴蝶( Petrocosmea qinlingensis W. T. Wang)群落的维管植物组成、垂直结构和分布区类型及其种群特征和土壤化学性质进行了调查和分析;在此基础上,初步探讨了该种类的濒危原因。调查结果显示：秦岭石蝴蝶为喜阴植物,仅分布于山体海拔约640 m的区域,种群面积仅约42 m2;土壤为黄棕壤,呈中性(pH 6.50),土壤中有机质含量较高,全氮、全磷和全钾含量较低,有效铁、有效镁、有效钠和有效钙含量则较高;秦岭石蝴蝶种群中个体数量约1000株,多生长于覆有土壤或苔藓的岩石上,也有部分成年个体生长在裸露且瘠薄的岩石上。秦岭石蝴蝶群落中共有维管植物28种,隶属于23科28属;其中,蕨类植物3科4属4种,裸子植物1科1属1种,被子植物19科23属23种,优势科和优势属不明显。秦岭石蝴蝶群落垂直结构明显,可分为乔木层、灌木层和草本层,其中,乔木层优势种为杜仲( Eucommia ulmoides Oliver),灌木层优势种为华西小石积( Osteomeles schwerinae Schneid.),草本层优势种为裂叶荨麻( Urtica lobatifolia S. S. Ying)。该群落维管植物科的分布型以热带分布型科为主,其中泛热带分布型科占明显优势;属的分布型以温带分布型属为主,其中北温带分布型属占优势;中国特有分布的科和属均很少;总体上看,该群落具有暖温带向亚热带过渡的特点。在秦岭石蝴蝶种群的不同样方中,成年个体和幼苗数量均有一定差异,成年个体占14.6%~37.5%,幼苗占61.3%~80.0%,幼苗数量明显高于成年个体;各样方的单株叶片数为7~9,冠幅为6.0~7.2 cm,大多数样方的单株结实量小于4,表明在同一个种群的不同生境中秦岭石蝴蝶的分布和生长状况有明显差异。根据调查结果,推测种群规模较小、分布范围狭窄以及人为干扰可能是造成秦岭石蝴蝶濒危的主要原因,而人为干扰是其中的重要原因。     

Effects of prenatal diclofenac sodium exposure on newborn testis: a histomorphometric study

Diclofenac sodium (DS) is used primarily to treat fever and to alleviate pain and inflammation. We investigated the effects of DS exposure during gestation on the testes of rat pups to investigate the safety of its use during the prenatal period. Pregnant rats were separated into control, saline, low dose, medium dose and high dose groups. DS was given between weeks 15 and 21 of gestation. Total numbers of spermatogonia and Sertoli cells were counted in the testes of 7-day-old male rats using the physical disector method. By the end of the study, the total number of Sertoli cells was decreased significantly in a dose dependent manner in the medium and high dose groups compared to controls. No significant differences were found in the total number of spermatogonia in the control, saline and low dose DS groups. Medium and high dose DS administration reduced the total number of spermatogonia compared to other groups. We suggest that prenatal administration of DS can cause deleterious effects on the testis development, especially in high doses.     

乳丝的加工、性能及其应用

乳丝学名为聚乳酸纤维,是一种可生物降解的新型绿色纤维,目前制备方法主要有熔融纺丝、溶液纺丝和静电纺丝等3种方法。作为一种新型的可降解纤维材料,其环保性、吸湿性、透气性、生物相容性以及优良的力学性能决定了其在生物医用、织物面料、非织造材料(如一次性卫生用品、过滤材料等)等很多方面都将得到广泛应用。     

川中丘陵区土地利用方式对土壤理化性质影响的灰色关联分析

以川中丘陵区小流域为研究对象,研究了坡耕地、坡改梯、甜橙林和水保林4种土地利用方式以及裸地(对照)对0～10和10～20 cm土壤容重、土壤孔隙度及土壤养分含量的影响.结果表明: 同一土地利用方式下,毛管孔隙度、非毛管孔隙度、总孔隙度、有机质、全氮、全磷、碱解氮、有效磷、速效钾随土层加深而减小,而土壤容重则相反,全钾层间差异不大.相同土层甜橙林毛管孔隙度、非毛管孔隙度、总孔隙度、全磷、有效磷含量最大,容重最小,水保林全氮、碱解氮含量最高,水保林0～10 cm土层的有机质含量最高,甜橙林10～20 cm土层的有机质含量最高.0～10 cm土层,灰色关联度从大到小依次为水保林(0.9441)、甜橙林(0.8858)、梯平地(0.6300)、裸地(0.5397)、缓坡耕地(0.4714);10～20 cm土层,灰色关联度依次为水保林(0.8919)、甜橙林(0.8401)、梯平地(0.5773)、裸地(0.5301)、缓坡耕地(0.5175).水保林改善土壤理化性质作用最佳,缓坡耕地改良效果最差.     

典型新建绿地上海辰山植物园土壤水库特征及其影响因子

研究不同植被类型、压实方式和土壤基本理化性质对典型新建绿地上海辰山植物园土壤水库的影响.结果表明:相对自然林地,植物园土壤总库容、滞洪库容、有效库容均较低,但死库容较大,占总库容的60.6%,这导致绿地蓄洪排涝能力减弱.植物园不同植被类型土壤总库容和滞洪库容大小依次为灌木地﹥乔木地﹥草地﹥竹林地﹥裸地,有效库容以灌木和乔木较高,而裸地和竹林地相对较低,裸地和竹林地死库容占总库容的比例最大,分别为65.5%和67.6%.灌木地总库容、滞洪库容和有效库容与裸地差异显著,植被能显著提高土壤的蓄水持水能力,但机械压实和人为践踏显著降低土壤总库容、滞洪库容和有效库容.土壤容重、饱和导水率、毛管孔隙度、非毛管孔隙度、总孔隙度、黏粒和有机质含量显著影响土壤水库,改善土壤理化性质能显著提高城市绿地土壤水库库容.     

陇东旱塬苹果根系分布规律及生理特性对地表覆盖的响应

为探明陇东旱塬区不同覆盖物对苹果园土壤理化性状、根系分布及根系生理活性的影响,以14年生苹果树为试材,采用土壤剖面分层取样法,调查根系空间分布,并对根系生物量、根长、表面积等进行分析,测定根系活力、抗氧化酶类、活性氧代谢等相关生理指标,同时测定不同深度土层土壤容重、孔隙度等.结果表明: 覆草可有效增大土壤含水量、孔隙度、有机质含量,增幅分别为2.7%～11.6%、3.2%～27.7%、5.1%～36.0%,但土壤容重降低,为清耕(CK)的88.7%～96.4%.CK根系主要分布在距树干30～120 cm范围内的0～60 cm深土层中;覆草、覆膜处理主要分布在距树干0～150 cm、0～60 cm水平范围内的0～100 cm深土层中,以20～40 cm根系最为密集;覆膜处理细根总量仅为CK的96.4%,根系水平分布范围较CK有所减小,0～60 cm内细根占根系总量的51.6%.不同覆盖处理显著增强0～80 cm土层根系活力及抗氧化酶活性,其中覆草处理根系活力为CK的111.3%～136.7%.综合分析根系生长分布与生理活性、土壤理化性状等,认为覆草处理是陇东旱塬区苹果园较为适宜的地表覆盖方式.     

Reducing Gaseous Emissions and Resource Consumption Embodied in French Final Demand: How Much Can Waste Policies Contribute?

This study investigates the benefits of waste management policies on gaseous emissions and resource consumption caused by the final demand, in the specific case of France and in a context of economic growth. Waste input‐output analysis is implemented to compare three scenarios, depicting and combining the upward trend of final demand from 2008 to 2020, the increase in recycling rates by 2020 (encompassing the achievement of recycling objectives set by European Union Directives), and the simultaneous larger implementation of best available techniques (BAT) for waste incineration. Hybrid monetary physical input‐output tables are initially derived from balanced physical supply and use tables and further complemented with process inventory data on waste treatment technologies. A dramatic reduction in the demand for primary metals (by a factor of 2.0) and for primary mining and quarrying products for construction (by a factor of 1.9) is observed in 2020, as compared to 2008, in the case of the scenario “recycling,” despite the competition induced by the evolution of the final demand. On the contrary, considering energy requirements and fossil carbon dioxide, sulfur dioxide, and nitrogen oxide emissions caused by the French final demand, the combined improvements in recycling and incineration performances by 2020 would only limit the rise induced by the evolution of the final demand. On the basis of these results, the potential contribution of waste management policies to the decoupling of resource consumption and gaseous emissions from final demand's growth is finally discussed.     

Investigation of asphalt aging behaviour due to oxidation using molecular dynamics simulation

An attempt is made to connect the link between internal chemical and molecular mechanical property change and external physical, rheological and mechanical property change for asphalt before and after oxidative aging using molecular dynamics (MD) simulation. Intermolecular interactions, density, bulk modulus and zero shear viscosity changes of model asphalt systems before and after oxidative aging and mechanical property changes of the asphalt systems under different compressive and tensile stress rates are investigated at room temperature (298 K). Simulation results demonstrate that oxidised functional groups in asphalt molecules increase the strength of intermolecular bonds and the bulk modulus of asphalt, which further contribute to the hardening of the oxidised asphalt. The internal property change is consistent with the external physical and rheological property change after oxidation, which is revealed by the increase of density and viscosity. In addition, both the unoxidised and oxidised asphalts deform more and fail faster with an increase in both compressive and tensile stress rates, especially under tensile stresses. The oxidised asphalt is stiffer than the unoxidised asphalt, which shows less deformation.     

Comprehensive simulation on morphological and mechanical properties of trigger finger – A cadaveric model

Trigger finger has long been a common disorder in hand orthopedics. To clarify the unknown causative factors regarding the disease, numerous experiments were done on human cadavers, including tendon forces, tendon moment arm, mechanical properties of the pulley, gliding resistance, etc. However, most of these studies were conducted on normal fingers. As the etiology of trigger finger is still controversial on whether it is an outcome of tendon nodule or pulley scarring, in this study, a trigger finger model was built combining both the nodule created by silicone gel injection and pulley constriction by external compression. Indentation and gliding resistance tests were performed on cadaveric specimens to verify the model. Results showed that after silicone gel injection into the tendon, a significant increase in thickness was found. In addition, no significant difference was found in the toe region compressive modulus of the tendon after injection. Moreover, maximum, drop of gliding resistance and work of extension were all found to be significantly larger as the severity of triggering increased. Our results indicated we have developed a feasible cadaver model simulating trigger finger nodule which could be utilized for further experiments to elucidate other causative factors and biomechanical features of trigger finger in the future.     

SENSORY DRIVE DOES NOT EXPLAIN REPRODUCTIVE CHARACTER DISPLACEMENT OF MALE ACOUSTIC SIGNALS IN THE UPLAND CHORUS FROG (PSEUDACRIS FERIARUM)

Biotic and abiotic factors have been proposed to explain patterns of reproductive character displacement, but which factor is most important to character displacement of acoustic signals is not clear. Male vocalizations of the frog Pseudacris feriarum are known to undergo reproductive character displacement in areas of sympatry with P. brimleyi and P. nigrita. Despite evidence for reinforcement as an important mechanism, local adaptation via sensory drive might explain this pattern because Pseudacris breed in different habitat types and mating signals are exposed to a variety of environments. We tested the sensory drive hypothesis by playing synthesized vocalizations representing the spectrum of variation in P. feriarum at 12 different study sites. If sensory drive has occurred, then vocalizations should transmit better in the site of origin or at ecologically similar sites. We found that variation in acoustic signals did not produce better transmission in particular sites, the effect of site was uniform, and acoustic signals often transmitted better in habitats external to their origin. Ecological variation among habitats did not explain signal degradation. Our playback experiments, ecological analyses, and comparisons of different habitat types provide no support for sensory drive as a process promoting reproductive character displacement in this system. Reinforcement is the more likely primary mechanism.