Reversibility of germinative and endocrine testicular function after long-term contraception with a GnRH-agonist implant in the tom—a follow-up study

A significantly reduced gonadotropin and testosterone secretion is a well-described result of long-term administration of GnRH agonists in the male dog and cat. To date, no data are available about the duration of efficacy and the reversibility of treatment-induced effects after long-term treatment with a 4.7 mg deslorelin implant. Seven healthy male European Shorthair cats (3.2 ± 0.5 kg, 1–6 years) were treated with a 4.7 mg deslorelin implant. Blood samples (testosterone, T), testicular volume, penile spines, and mating behavior were recorded once weekly. Considering T > 0.5 ng/mL as the biological endpoint, mean duration of efficacy was 78.8 ± 12.9 weeks (range: 61.7–100.7 weeks) with T concentrations increasing rapidly after the last T less than 0.1 ng/mL (basal) (P < 0.0001), and pretreatment T concentrations being reached after 3 weeks. Testicular volume rapidly increased after the first increase of T (P < 0.001) with pretreatment testicular volume being reached after 6.9 ± 3.4 weeks (5–11 weeks). “Normal” libido reoccurred 88.7 ± 12.4 weeks after treatment, and “normal” mating behavior was observed even later. Fertile matings occurred 7 to 42 weeks after the last T less than 0.1 ng/mL with a mean of 4.0 ± 0.0 kittens, and 13.6 to 47.6 weeks afterwards testicular histology revealed normal spermatogenesis. The present data confirm that the use of slow-release GnRH-agonist implants containing deslorelin in tomcats represents an effective and safe reversible alternative for long-term contraception; however, as number of animals is low, further fertility trials are recommended.     

无线遥测和刺激技术建立兔房颤模型的探索

目的探索一种在无线遥测和刺激技术基础上的兔房颤模型的制作。方法新西兰兔皮下植入自主研发的植入式遥测刺激器,植入式遥测刺激器的制作是以TI公司（德州仪器）的MSP单片机和TI公司的RF无线收发芯片CC2250为核心开发设计。优化植入系统设计以满足新西兰兔房颤模型建立的探索实验;植入子植入新西兰兔腹部皮下,采集电极留置于左上肢和右上肢腋下皮下,两个刺激电极分别缝合于左心耳和左心房上,通过无线收发采集和刺激信号;实现利用Powerlab生理记录仪连续监测体表I导联心电信号,并通过专用计算机程序刺激软件,发放间歇（刺激2 s,暂停2 s）高频（频率20 Hz）阈上（强度2 mA,脉宽1 ms）刺激,若间歇期内出现房颤,则人为干预中止刺激,若转为窦性心律,则继续刺激。结果植入式遥测刺激器在体内可稳定工作（包括采集模拟心电信号和发放刺激）30 d,植入新西兰兔体内刺激3周后可诱导出房颤,持续时间〉48 h。结论用新西兰兔代替比格犬建立基于无线遥测和刺激基础上的房颤模型是完全可行的,同时也体现了动物福利优化和替代原则。     

人巨细胞病毒感染对学习记忆影响的研究进展

巨细胞病毒感染可影响儿童的学习记忆能力,是导致儿童智力残疾的主要原因之一。长期以来相关研究主要集中于巨细胞病毒先天性感染对学习记忆的影响及其机制。近年来,越来越多研究也开始关注围生期及获得性巨细胞病毒感染。本综述旨在对近期的巨细胞病毒感染致学习记忆损伤的研究现状加以概括总结。     

Effects of long-term rainfall variability on evapotranspiration and soil water distribution in the Chihuahuan Desert: A modeling analysis

We used the patch arid land simulator (PALS-FT) – a simple, mechanistic ecosystem model – to explore long-term variation in evapotranspiration (ET) as a function of variability in rainfall and plant functional type (FT) at a warm desert site in southern New Mexico. PALS-FT predicts soil evaporation and plant transpiration of a canopy composed of five principal plant FTs: annuals, perennial forbs, C₄ grasses, sub-shrubs, and evergreen shrubs. For each FT, the fractional contribution to transpiration depends upon phenological activity and cover as well as daily leaf stomatal conductance, which is a function of plant water potential, calculated from root-weighted soil water potential in six soil layers. Simulations of water loss from two plant community types (grass- vs. shrub-dominated) were carried out for the Jornada Basin, New Mexico, using 100 years of daily precipitation data (1891–1990). In order to emphasize variability associated with rainfall and fundamental differences in FT composition between communities, the seasonal patterns cover of perennials were held constant from year to year. Because the relative amount of year to year cover of winter and summer annual species is highly variable in this ecosystem, we examined their influence on model predictions of ET by allowing their cover to be variable, fixed, or absent.Over the entire 100-yr period, total annual ET is highly correlated with total annual rainfall in both community types, although T and E alone are less strongly correlated with rainfall, and variation in transpiration is nearly 3 times greater than evaporation and 2 times greater than variation in rainfall (CV of rainfall = 35%). Water use shows a relatively high similarity between the grass- and shrub-dominated communities, with a 100-yr average T/ET of 34% for both communities. However, based on a year-by-year comparison between communities, T/ET was significantly greater in the grass-dominated community, reflecting the fact that over the long term more than half of the rain occurs in the summer and is used slightly more efficiently (T¿E) by the C₄-grass community than the shrub community, although we found some rainfall patterns that resulted in much greater T/ET in the shrub community in a given year. Percent of water lost as transpiration (T/ET) suggests that while there is a general trend toward increased T/ET with rainfall in both community types, T/ET is extremely variable over the 100-yr simulation, especially for normal and below normal amounts of rainfall (T/ET values range from 1 to 58% for the grass-dominated site and 6 to 60% for the shrub-dominated site).These predictions suggest that because of the relatively shallow distribution of soil water, there is little opportunity for vertical partitioning of the soil water resource by differential rooting depths of the plant FTs, in contrast to the two-layer hypothesis of Walter (1971). However, functional types may avoid competition by keying on particular `windows' of moisture availability via differences in phenologies. We found very little differences in average, long-term model predictions of T, E, and ET when annual plant cover was variable, fixed, or absent. The results of our simulations help reconcile some of the disparate conclusions drawn from experimental studies about the relative contribution of transpiration vs. evaporation to total evapotranspiration, primarily by revealing the great year-to-year variability that is possible.     

鸭儿湖地区六氯环己烷的残留动态与长期归宿

在１９９０－１９９３年期间,研究了历史上曾被ＨＣＨ严重污染的鸭儿湖地区的水生态系统和陆生生态系统中ＨＣＨ的残留动态与时宿,获得了ＨＣＨ在各种不同环境条件下的残留动态方程与环境半衰期。结果表明：鸭儿湖底泥是ＨＣＨ长期残留的主要归宿。尽管ＨＣＨ已禁用十几年,目前该地区环境中ＨＣＨ的残留已降至亚ｎｇ／ｇ级水平,然而它在淡水食物链中仍然存在很高的生物积累。残留的ＨＣＨ在各种环境中的分布和转移均与该地区有机     

长期生态研究中的若干重要问题及趋势

长期生态研究（LTER）是对生态过程进行长期的监测,研究各种生态因子的相互作用及生态过程,从而揭示出生态系统和环境的长期变化。为生态系统评价管理提供科学依据。本文探讨了长期生态研究的核心问题及其时空尺度,揭示出长期生态所注重的问题及其对策,并以国际长期生态研究计划为例论述了生态研究所关注的内容并提出了研究的发展趋势,这对中国的长期生态研究及陆地生态系统评价有着积极的指导作用。     

Individualistic responses of bird species to environmental change

We investigated how the population dynamics of the same bird species varied in different environments, and how the population dynamics of different species varied in the same environment, by calculating long-term population trends for 59 insectivorous songbird species in 22 regions or strata of eastern and central North America using data from the North American Breeding Bird Survey. Of the 47 species that occurred in more than one region 77% increased in some regions and declined in others. Of the 22 regions 91% had some species that increased and others that decreased. There were only slightly more significant correlations between strata in species trends and between species for stratum trends than would be expected by chance. Because of nonlinearities in the data, the actual patterns of population fluctuations of the same species in different regions and of different species in the same region were even more heterogeneous than suggested by our analyses of linear trends. We conclude that these bird species respond to spatial and temporal variation in their environment in a very individualistic fashion. These individualistic responses show that the extrapolation of population trends gained from a few local studies to a larger spatial scale, and the use of a few indicator species to monitor the status of a broader community, are suspect.     

Comparative genetics of invasive populations of walnut aphid,Chromaphis juglandicola,and its introduced parasitoid,Trioxys pallidus,in California

Coevolution may be an important component of the sustainability of importation biological control, but how frequently introduced natural enemies coevolve with their target pests is unclear. Here we explore whether comparative population genetics of the invasive walnut aphid, Chromaphis juglandicola, and its introduced parasitoid, Trioxys pallidus, provide insights into the localized breakdown of biological control services in walnut orchards in California. We found that sampled populations of C. juglandicola exhibited higher estimates of genetic differentiation (F_ST) than co‐occurring populations of T. pallidus. In contrast, estimates of both the inbreeding coefficient (G_IS) and contemporary gene flow were higher for T. pallidus than for C. juglandicola. We also found evidence of reciprocal outlier loci in some locations, but none showed significant signatures of selection. Synthesis and applications. Understanding the importance of coevolutionary interactions for the sustainability of biological control remains an important and understudied component of biological control research. Given the observed differences in gene flow and genetic differentiation among populations of T. pallidus and C. juglandicola, we suspect that temporary local disruption of biological control services may occur more frequently than expected while remaining stable at broader regional scales. Further research that combines genomewide single nucleotide polymorphism genotyping with measurements of phenotypic traits is needed to provide more conclusive evidence of whether the occurrence of outlier loci that display significant signatures of selection can be interpreted as evidence of the presence of a geographic mosaic of coevolution in this system.     

浙北平原乡镇农业生态系统结构与功能现状及其相关性研究

调查分析了浙北平原15个乡镇农业生态系统的结构和功能现状,采用聚类分析和相关分析相结合的方法,研究了系统整体结构与功能以及结构和功能两两指标间的相关性。结果表明,聚类分析能揭示系统整体结构与功能的相关性,有利于从总体上把握调整的方向;两两指标间的相关分析可以明确持定结构和功能指标间相互关系的密切程度和方向,为有针对性地进行结构调整和功能优化提供依据。     

不同体质量指数对腹腔镜结直肠癌切除术患者临床疗效和远期预后的影响

摘要 目的：研究不同体质量指数（BMI）对腹腔镜结直肠癌切除术患者临床疗效和远期预后的影响。方法：将从2014年1月～2016年1月于我院接受腹腔镜结直肠癌切除术治疗的110例患者纳入研究。将所有受试者根据BMI的差异分作正常组（18.6 kg/m²≦BMI<23.0 kg/m²）35例、超重组（23.0 kg/m²≦BMI<25.0 kg/m²）53例、肥胖组（BMI≧25.0 kg/m²）22例。分析三组患者各项基线资料,临床疗效,术后并发症发生情况,远期预后等方面的差异。结果：三组患者各项基线资料比较差异均不明显（均P＞0.05）。肥胖组手术时长为（268.01±36.14）min,均明显高于正常组、超重组的（211.73±30.56）min、（224.12±34.87）min（均P＜0.05）;三组术中失血量、肛门排气时间以及住院康复时间对比均不明显（均P＞0.05）。三组患者术后肺部感染、下肢静脉血栓、切口感染以及吻合口出血发生率对比均不明显（均P＞0.05）。正常组5年生存率为45.71%（16/35）,超重组5年生存率为47.17%（25/53）,肥胖组5年生存率为45.45%（10/22）,三组比较差异无统计学意义（均P＞0.05）。结论：不同BMI对腹腔镜结直肠癌切除术患者的手术时长具有一定影响,但和远期预后无关,值得临床重点关注。