Evaluation and control of the nutritional status of cereals

Summary A quantitative therapy method was developed for predicting and controlling grain yields of oats and spring wheat based on methods of diagnosis and yield pronosis and on effects of supplementary applications of nutrients on the chemical composition of the young plant at a fixed Dry Matter weight-level.The characteristic interactions integrated in the models of therapy and depending on kind, source, amount and combination of the nutrient applications on the chemical composition of the young plant allow selection of the best possible nutrient therapy under the given circumstances.The therapy method, tested by comparing predicted with experimentally obtained nutrient concentrations in the young plant, was proved reliable by the high and highly significant correlation coefficients (r>0.9;p<0.001). The correctness of the basic concepts underlying the therapy method, was thus indirectly confirmed and the possibility to use the method in agricultural practice would appear promising.     

Modification of saltmarsh for mosquito control in Australia alters habitat use by nekton

The most common modification of saltmarsh habitat for mosquito control in Australia is runnelling, a system of shallow channels increasing seawater exchange in pools high on the marsh. Local effects within the immediate vicinity of runnels were examined by testing the hypothesis that fish assemblages immediately alongside runnels differ from those further away. Nekton assemblages were sampled using pop nets in winter (May) and summer (December) on a saltmarsh in southeast Queensland, alongside runnels and further (30 m) away, at two distances from a mangrove-lined intertidal creek. Nekton assemblages were dominated numerically (50–80%) by one or two species of small fish (Ambassis marianus, Mugilogobius stigmaticus), and a commercially important prawn, Fenneropenaeus merguiensis. In winter, nekton assemblages alongside runnels were significantly different from those further away. Species richness, total nekton densities and densities of several individual species were higher away from runnels, but only at sites far from the creek. No differences in species richness or densities were found in summer. During both periods, nekton assemblages differed strongly with distance from the creek, with more species and higher densities of most species near the creek. For most species, the overall effect of runnelling appears to be a reduction in abundances in the immediate vicinity of runnels, at some times of year. This is probably related to lower prey availability near runnels. Given the extent of runnelling in some parts of Australia, even this local reduction in densities extending no more than 30 m from runnels means that nekton may be adversely affected over a large total area. The apparent influence of runnels on nekton densities highlights the potential effects of saltmarsh modification on non-target animals that should be considered as this management technique becomes more prevalent.     

浙北地区不同种植方式下春玉米生长发育的动态模拟

在MACROS模型基础上根据田间试验和文献资料组建了春玉米动态模拟模型,经验证模型能较好地反映不同种植方式下春玉米的生长发育过程,利用模型研究了浙北地区大麦／春玉米－晚稻种植制度中春玉米的播种日期对其生育期、产量等的影响,结果表明3月底至4月上旬是这一地区理想播种期;与单作相比,套作玉米应适当增加植株密度。     

鲤春血症病毒中国分离株糖蛋白基因和氨基酸序列的初步解析

2002～2004年间从国内养殖鲤科鱼类和观赏鱼类中分离出8株鲤春血症病毒(SVCV).根据SVCV参考株全序列,设计引物,用逆转录聚合酶链式反应扩增出8株SVCV糖蛋白编码基因片段,并对扩增产物进行了克隆和序列测定.用生物信息学方法对测得的序列进行分析,结果8个国内分离株的糖蛋白基因序列与参考株的基因序列相似性均在92%以上,8个国内分离株之间基因序列相似性均在97.7%以上;8个国内分离株之间糖蛋白推导出的氨基酸序列相似性均在94.5%以上,与参考株氨基酸序列相似性在92.9%-94.9%之间.系统发育树分析结果表明,SVCV国内分离株与USA株、980451株、980528株和970469株的进化方向一致,与其它SVCV毒株在进化方向上不同.8个毒株有19个共同的酶切位点,推导出的氨基酸序列中有10个亲水区、10个可能的抗原位点和10个跨膜蛋白区域,其峰值基本一致.对SVCV国内分离株的糖蛋白6个功能位点(天冬酰胺糖基化位点、精氨酸-甘氨酸-天冬氨酸序列、酪蛋白激酶Ⅱ磷酸化位点、蛋白激酶C磷酸化位点、酪氨酸磷酸化位点和肉豆蔻酰基化位点)进行了初步分析.     

Kinematics of lower limbs during walking are emulated by springy walking model with a compliantly connected,off-centered curvy foot

The dynamics of the center of mass (CoM) during walking and running at various gait conditions are well described by the mechanics of a simple passive spring loaded inverted pendulum (SLIP). Due to its simplicity, however, the current form of the SLIP model is limited at providing any further information about multi-segmental lower limbs that generate oscillatory CoM behaviors and their corresponding ground reaction forces. Considering that the dynamics of the CoM are simply achieved by mass-spring mechanics, we wondered whether any of the multi-joint motions could be demonstrated by simple mechanics. In this study, we expand a SLIP model of human locomotion with an off-centered curvy foot connected to the leg by a springy segment that emulates the asymmetric kinematics and kinetics of the ankle joint. The passive dynamics of the proposed expansion of the SLIP model demonstrated the empirical data of ground reaction forces, center of mass trajectories, ankle joint kinematics and corresponding ankle joint torque at various gait speeds. From the mechanically simulated trajectories of the ankle joint and CoM, the motion of lower-limb segments, such as thigh and shank angles, could be estimated from inverse kinematics. The estimation of lower limb kinematics showed a qualitative match with empirical data of walking at various speeds. The representability of passive compliant mechanics for the kinetics of the CoM and ankle joint and lower limb joint kinematics implies that the coordination of multi-joint lower limbs during gait can be understood with a mechanical framework.     

Temperature sensitivity of spring vegetation phenology correlates to within-spring warming speed over the Northern Hemisphere

The inter-annual shift of spring vegetation phenology relative to per unit change of preseason temperature, referred to as temperature sensitivity (days °C⁻¹), quantifies the response of spring phenology to temperature change. Temperature sensitivity was found to differ greatly among vegetation from different environmental conditions. Understanding the large-scale spatial pattern of temperature sensitivity and its underlying determinant will greatly improve our ability to predict spring phenology. In this study, we investigated the temperature sensitivity for natural ecosystems over the North Hemisphere (north of 30°N), based on the vegetation phenological date estimated from NDVI time-series data provided by the Advanced Very High Resolution Radiometer (AVHRR) and the corresponding climate dataset. We found a notable longitudinal change pattern with considerable increases of temperature sensitivity from inlands to most coastal areas and a less obvious latitudinal pattern with larger sensitivity in low latitude area. This general spatial variation in temperature sensitivity is most strongly associated with the within-spring warming speed (WWS; r = 0.35, p < 0.01), a variable describing the increase speed of daily mean temperature during spring within a year, compared with other factors including the mean spring temperature, spring precipitation and mean winter temperature. These findings suggest that the same magnitude of warming will less affect spring vegetation phenology in regions with higher WWS, which might partially reflect plants’ adaption to local climate that prevents plants from frost risk caused by the advance of spring phenology. WWS accounts for the spatial variation in temperature sensitivity and should be taken into account in forecasting spring phenology and in assessing carbon cycle under the projected climate warming.     

Physiological and psychological responses of young males during spring-time walks in urban parks

Background

It is widely believed that contact with the natural environment can improve physical and mental health. Urban green spaces may provide city residents with these benefits; however, there is a lack of empirical field research on the health benefits of urban parks.

Methods

This field experiment was performed in May. Seventeen males aged 21.2 ± 1.7 years (mean ± standard deviation) were instructed to walk predetermined 15-minute courses in an urban park and a nearby city area (control). Heart rate and heart rate variability (HRV) were measured to assess physiological responses. The semantic differential (SD) method, Profile of Mood States (POMS), and State-Trait Anxiety Inventory (STAI) were used to measure psychological responses.

Results

Heart rate was significantly lower while walking in the urban park than while walking in the city street. Furthermore, the urban park walk led to higher parasympathetic nervous activity and lower sympathetic nervous activity compared with the walk through the city street. Subjective evaluations were generally in accordance with physiological reactions, and significantly higher scores were observed for the ‘comfortable’, ‘natural’, and ‘relaxed’ parameters following the urban park walk. After the urban park walk, the score for the ‘vigor’ subscale of the POMS was significantly higher, whereas that for negative feelings such as ‘tension-anxiety’ and ‘fatigue’ was significantly lower. The score for the anxiety dimension of the STAI was also significantly lower after the urban park walk.

Conclusions

Physiological and psychological results from this field experiment provide evidence for the physiological and psychological benefits of urban green spaces. A brief spring-time walk in an urban park shifted sympathetic/parasympathetic balance and improved mood state.     

山西省辛安泉泉域弧形串珠藻物候期的研究

对山西省辛安泉泉域弧形串珠藻的物候期进行了研究。2005年1月至10月对标本进行了4次采集（每个季节1次）,同时对每个采样点的环境因子如气温,水温,流速,pH,溶氧,电导进行了监测和记录。在显微镜下对弧形串珠藻的10个主要形态特征进行了观察和测量。研究结果表明,所有的环境因子都有不同程度的季节变化,而且弧形串珠藻的某些形态特征也表现出了明显的季节变化,在春季生长良好,夏季生长相对较差。同时将环境因子对其的影响也作了相关性分析,结果表明,尽管弧形串珠藻的生长发育在一定程度上受环境的影响,但最主要的影响因素还是其自身的生物发育规律。     

中国春ph2b突变体×华山新麦草F1自交和回交一代细胞遗传学研究

用中国春ph2b突变体（Triticum aestivum L.cv.Chinese Spring）与华山新麦草（Psathyrostachys huashanica Keng）杂种F1的部分进行自交,而另一部分与3个不同的普通小麦品种以及中国春ph2b突变体进行回交,并对自交和回交一代的形态学和细胞学进行研究.结果表明：（1）含有AABBDDNs的自交F2的花粉母细胞减数分裂中期Ⅰ平均单价体数都在7以上,说明来自华山新麦草的Ns基因组可引起普通小麦ABD基因组中某一个（几个）同源组发生不联会或联会消失;（2）在回交一代（F1×CS、F1×CSph2b）中,平均单价体数都在7以下,说明其中的ph2b基因起到了促进染色体配对的作用;而在回交一代（F1×J-11、F1×郑麦-9023）中,则表现正常,与理论一致;（3）在所有自交和回交一代中,减数分裂期间均出现染色体桥、落后染色体、三分孢子体、多分孢子体以及微核等各种染色体异常行为,说明Ns基因组引起了所得材料细胞学上的不稳定性.从总体上讲,回交比自交能更快地恢复ph2b基因促进部分同源染色体配对的作用,为染色体重组提供更多的机会,期望在后代中获得新种质.