Greater temperature sensitivity of plant phenology at colder sites: implications for convergence across northern latitudes

Warmer temperatures are accelerating the phenology of organisms around the world. Temperature sensitivity of phenology might be greater in colder, higher latitude sites than in warmer regions, in part because small changes in temperature constitute greater relative changes in thermal balance at colder sites. To test this hypothesis, we examined up to 20 years of phenology data for 47 tundra plant species at 18 high‐latitude sites along a climatic gradient. Across all species, the timing of leaf emergence and flowering was more sensitive to a given increase in summer temperature at colder than warmer high‐latitude locations. A similar pattern was seen over time for the flowering phenology of a widespread species, Cassiope tetragona. These are among the first results highlighting differential phenological responses of plants across a climatic gradient and suggest the possibility of convergence in flowering times and therefore an increase in gene flow across latitudes as the climate warms.     

Circular Polarization of Light by Planet Mercury and Enantiomorphism of its Surface Minerals

Different mechanisms for the generation of circular polarization by the surface of planets and satellites are described. The observed values for Venus, the Moon, Mars, and Jupiter obtained by photo-polarimetric measurements with Earth based telescopes, showed accordance with theory. However, for planet Mercury asymmetric parameters in the circular polarization were measured that do not fit with calculations. For BepiColombo, the ESA cornerstone mission 5 to Mercury, we propose to investigate this phenomenon using a concept which includes two instruments. The first instrument is a high-resolution optical polarimeter, capable to determine and map the circular polarization by remote scanning of Mercury's surface from the Mercury Planetary Orbiter MPO. The second instrument is an in situ sensor for the detection of the enantiomorphism of surface crystals and minerals, proposed to be included in the Mercury Lander MSE.     

The recovery of benthic foraminifera and bacteria after disturbance: experimental evidence

In experiments with living meiofauna, sediment is often sieved prior to incubation. This is primarily to remove macrofauna and to increase reproducibility among replicates. At the onset of the experiment, the bacteria are severely disturbed. The effects of these disturbances are ill-known but might affect the outcome of the experimental meiofaunal and biogeochemical studies substantially.We compared the disturbance induced by sieving with the disturbance in microcosms from which meiofauna was removed by flushing with argon. Both experimental situations were compared with untreated cores and the field situation. Neither sieving nor flushing induced changes in the composition of the foraminiferal community compared with the natural situation; the four most abundant species found in the field remained dominant during the experiment. Sieving led to a pronounced disturbance in both bacterial as well as foraminiferal abundance patterns. The depth distribution of some species seems to be related to food, although bacteria might play a regulating role as well.     

New record of predatory behavior by the mandrill in Cameroon

The predatory behavior of the mandrill (Mandrillus sphinx,Linnaeus 1758), a forestliving baboon, on the bay duiker (Cephalophus dorsalis,Gray 1864) was observed under natural conditions. In the predatory episode, at least two mandrills (one adult female and one adult male) attacked a bay duiker, but no overt aggressive interactions between the attackers occurred during consumption. The estimated predation pattern based on scars—intensive attacking of the head and pulling of the hind legs to eat the thigh muscles first—resembled the predation patterns of captive mandrills observed experimentally. The findings suggest that the predatory behavior is established in mandrills as a feeding behavior pattern as in savanna-living baboons. New data are thus presented which are relevant to the discussion of the origins of hunting behavior in early hominids.     

Vegetation development in a former orchard under different treatments: A preliminary report

Summary Vegetation development in a former orchard on loamy moist soil after removal of the fruit trees under different treatment is described with the help of multivariate methods. Data on 20 plots over 9 years are treated with a simple classification program and a PCA ordination. Two main groups of plots are involved: one in a relatively moist part of the area where the trees were removed in 1970, one in a slightly drier area where the trees had been removed earlier. The first group is characterized by forbs such as Urtica dioica and Lamium maculatum, the second by grasses, mainly Arrhenatherum elatius.Under a mowing regime the plots of the first group change in the direction of the second group. Under continued fertilization the Urtica vegetation can be maintained. Establishment and/or rapid spread of Urtica can be brought about in Arrhenatherum dominated sites by (re-) introduction of nitrogen fertiliser.Not mowing leads to a dense Urtica-Lamium stand in which Lamium maculatum finds an optimum some years after mowing is stopped.The methods of summarizing the site-time data are discussed and some new ones announced for further research.Nomenclature follows Heukels-van Ooststroom, Flora van Nederland, 18e druk, Wolters-Noordhoff, Groningen, 1975.Vegetation and soil analyses were mainly carried out by students in the framework of their study for the degree of doctorandus in biology: Ineke Opbroek, Ferdinand Baggerman (1970), Carla Veldhuis (1971–1972), the late Doeke Dijken (1971–1973), Jos Rijpert (1972), the Rev. Piet van der Aart, Jo Louppen (1973), Frank Verhoeven (1974), Maurits Heine (1975), Ad Peters (1976), Huub Muyres, Louis Fliervoet (1976, 1977), Emilia Peters (1977), Niek Joanknecht, Thijs Lavrijsen (1977, 1978).     

Predicting the effect of relative humidity on skin temperature and skin wettedness

The purpose of this research is to investigate the relative humidity effects on skin temperature and skin wettedness for different operative temperatures. For this aim, thermal interactions between human body and environment are simulated. In this simulation, Gagge 2-node model is used but includes some significant modifications. The simulation is to apply the Gagge 2-node model to individual segments rather than to whole body. Also, the results of the simulation are compared with present measurements, and available experimental data and simulated results in the literature in order to present reliability of the 16 segments-Gagge 2-node model. It is determined that the simulation results are in good agreement with measured results obtained from present experiments, and simulated results and experimental data in the literature.     

诊断学实验教学中形态学标本的保存与制备

在实验诊断学的实验教学中,形态学标本如管型,病理性脑脊液等的来源越来越困难,尤其是在时间上,标本的来源有随机性,而上课时间是固定的,教学质量很难,要解决这个问题,就必须研究标本的保存与人工制备.作者经过多年的探索与实践,获得了一些标本的保存和制备的体会,这样既保证了教学质量,又减轻了寻找阳性标本的难度.     

环境工程微生物学实验教学改革与实践

阐述了环境工程微生物学实验教学的改革实践,通过对课程设置、教学内容、教学方式、教学手段及考核方式等方面进行不断的改革与完善,很大地提高了教学质量。     

微生物多样性研究的教学设计及效果分析

微生物实验教学的目标是既要让学生掌握基本实验技能, 又要扩展学生的知识面, 让他们了解科学发展的前沿。本文通过将微生物多样性研究的实验引入本科微生物实验教学中, 可以使学生初步了解微生物基因组学及微生物分子生态学的相关研究, 激发学生的学习热情, 提高学生的科研创新能力。该实验操作简单, 结果明确, 教学成本低, 便于在高校中开展。