Feed intake and oral behaviour of dairy calves housed individually or in groups in warm or cold buildings

The influence of environmental temperature, housing, social company and age on the feed intake and oral behaviours was studied by housing male dairy calves for seven weeks individually (INDIV) or 12 weeks in groups of four; indoors (INGROUP) or outdoors either with (OUTWARM) or without a heated shelter (OUTCOLD). During the milk-feeding period (1–7 experimental weeks), the mean daily milk, hay and total dry matter intakes of INDIV calves were lower than of INGROUP calves (P < 0.05). No differences in the feed intake between OUTWARM, OUTCOLD or INGROUP were found. Nor was found any differences in the feed efficiency (growth kg^− 1 DM) between the treatments. After weaning off milk, during experimental weeks 8 to 11, the total dry matter intake of INGROUP tended to be greater than that of OUTWARM (P = 0.05). There were no other differences in the mean daily feed intakes, nor in the feed efficiency. During the milk-feeding period, INGROUP calves ate more often concentrates (P = 0.05) and ruminated more (P = 0.01) than INDIV calves. During the 12-week experiment, INGROUP calves licked themselves more often than OUTCOLD calves (P = 0.04) and tended to lick more often than OUTWARM calves (P = 0.08). INGROUP calves licked more often penmates or structures and bit more often structures than OUTWARM or OUTCOLD calves (P < 0.05 for all). Overall, with a decreasing temperature, the calves in outside groups spent less time performing oral behaviours. We conclude that group rearing may facilitate calves to start eating and ruminating earlier than individual housing. The effect of low temperatures on the time spent eating solid foods is discussed in relation to housing design.     

创新能力本质和大学生创新潜能培养对策

针对目前学术界对创新能力和创新潜能的模糊认识,对其进行区别辨析,明确了创新能力是通过创新作品的高价值性来确定的本质,提出个体创新能力形成的模式并遵循这个模式,从培养大学生专业兴趣、完善创新潜能、建立创新意识淘汰机制、尽早开展创新实践活动等方面入手,探索促进大学生创新能力形成的可能途径。     

Biomonitoring using tagged sentinel fish and acoustic telemetry in commercial salmon aquaculture: A feasibility study

We tested if it is technically feasible to monitor fish in real-time in full-scale commercial fish farms using acoustic telemetry. 31 Atlantic salmon were equipped with acoustic transmitter tags containing depth sensors. Tagged fish were monitored for three months in two industrial scale sea-cages containing 180000 and 150000 fish, respectively. Each cage was fitted with two prototype acoustic receiver units designed to collect, interpret and store the information transmitted by the acoustic transmitter tags. Ten in each cage were also equipped with Data Storage Tags (DSTs) containing depth sensors to record individual-based datasets for comparison with the acoustically transmitted datasets. After compensation for sample loss caused by expected acoustic interference between the transmitter tags, the resulting dataset revealed that the receiver units collected 90–95% of the signals in both cages. Acoustic communication conditions in the sea-cages were not strongly impaired by factors such as fish density and local noise. Further, the dataset from the acoustic transmitters had comparable resolution and quality to that produced by the DSTs. However, acoustic tags provide data in real time and enable farmers to respond to the received information with farm management measures, whereas archival tags such as DSTs need to be retrieved and downloaded and hence have no real-time applications. We conclude that acoustic telemetry is feasible as a method to monitor the depth of fish in real-time commercial aquaculture.     

氮添加和放牧对云雾山草原优势种异速生长模式的影响

氮添加和放牧是影响草地生态系统结构和功能的重要因素。本研究以宁夏云雾山典型草原为研究对象,采用标准化主轴估计和异速生长分析,探究了氮添加和放牧干扰对草地群落中7种优势植物根、茎、叶不同构件的生物量分配对策和异速生长模式（包括异速生长斜率和截距）的影响。结果表明：在封育地,氮添加处理显著提高了物种的叶生物量;而在放牧地,氮添加则使得物种的根生物量上升,而茎、叶生物量下降;植物各营养器官生物量均随植物个体生物量的增加而增加,且只有在放牧×氮添加处理下植物叶生物量与个体生物量之间的异速生长斜率和截距发生了显著改变,其余处理下植物的异速生长斜率均无明显差异。因此,植物营养器官的生物量分配主要依赖于植物个体大小,而氮添加和放牧对植物异速生长模式的影响相对较小。     

Pattern-oriented modelling for estimating unknown pre-breeding survival rates: The case of the Lesser Spotted Woodpecker (Picoides minor)

In population viability analysis we are often faced with a lack of knowledge of survival rates in animal populations. In particular, survival of recruits is usually hard to assess. However, data on population structure might be considered as patterns that contain valuable information to estimate missing parameters indirectly. As an example for this pattern-oriented modelling and parameterization, pre-breeding survival rate of the endangered Lesser Spotted Woodpecker (Picoides minor) was determined here using data on population structure (e.g. sex ratio) and reproductive success at the population level (e.g. nesting success). Therefore, an individual-based model was developed simulating the population dynamics for two different populations that had been empirically studied at Lake Möckeln, Sweden, and Taunus, Germany. For both populations, a small range for pre-breeding survival rates could be identified wherein all simulated patterns corresponded best to the empirical values. Pre-breeding survival rate was found to be higher in the German scenario than in the Swedish and geographical variation in life-history traits is discussed as a possible reason. It is concluded that the pattern-oriented approach is a valuable method for estimating missing demographic parameters, even when using weak patterns from empirical investigations. Furthermore, it was shown that the use of multiple patterns is necessary for this purpose.     

不同个体和日龄新罗曼蛋鸡血液生化指标变化的研究

采集5只302、304、306、308、310日龄不同个体的新罗蛋鸡静脉血,连续采血5次,测定血液中9个指标的含量。结果表明:淀粉酶(AM)、钙(Ca)、总蛋白(TPROT)、谷丙转氨酶(ALT)含量有个体和日龄差异;AMS随日龄变化,差异极显著(p<0.01),ALT随日龄变化,差异显著(p<0.05),TPROT随日龄变化,差异极显著(p<0.01),Ca随个体差异显著(p<0.05),日龄差异极显著(P<0.01)。其它指标差异不显著。     

Targeting rural development interventions: Empirical agent-based modeling in Nigerien villages

The aim of this article is to analyze the impact of development interventions on the population of three Nigerien villages that differ in terms of their agro-ecological, social and economic characteristics. This is performed by simulating the behavior of individuals in an agent-based modeling framework which integrates the village characteristics as well as the family internal rules that condition access to economic and production activities. Villagers are differentiated according to the social and agro-ecological constraints they are subjected to. Two development project interventions are simulated, assuming no land scarcity: increasing the availability of inorganic fertilizers for farmers and an inventory credit technique based on millet grain. Two distinct approaches were used to model the rationale of farmers’ decision making: gains or losses in economic value or gains or losses in within-village “reputation”. Our results show that village populations do not respond en masse to development interventions. Reputation has little effect on the population behavior and should be considered more as a local proxy for wealth amongst villagers, suggesting the monetization of these societies. Populations involve themselves in the two simulated development interventions only at sites where savings are possible. Some level of household food security and investment capacity is actually required to take part in the development interventions, which are largely conditioned by family manpower and size. As long as uncultivated land remains available in the village territory, support for inorganic fertilizers has little impact in the absence of any intensification process. Inventory credit engages a maximum of 25% of the population at the site with medium agro-ecological conditions. Therefore, both interventions should be viewed as a potential support tool for a limited part of the population capable of going beyond the survival level, but not as a generic poverty-alleviation panacea.     

基于机载激光雷达技术的茂密林地单株木识别

提出一种利用LiDAR数据进行单株木识别的方法,首先利用广义高斯模型分解全波形LiDAR数据,得到高密度的点云和相应的波形参数,通过建立数字高层模型得到非地面点云,然后计算点云的空间特征得到林木点云,最后在3D空间中利用马尔可夫随机场重新标记得到单株木点云.实验表明,与传统方法相比,本文方法能有效提高单株木识别的准确性,特别是对茂密林地中低矮、细小林木识别效果明显,平均识别精度达到75％.     

苗期追施氮肥对紫花苜蓿生长的影响(1988年)

试验结果表明:在氮素缺乏的江西红壤丘陵岗地上种植紫花苜蓿时,通过苗期追施氮肥可以促进紫花苜蓿的生长.在一次追施5kg/亩尿素时,花期株高、根长及单株根瘤数分别比对照高32.5%,22.4%及49.5%.     

卫星搭载对紫花苜蓿当代植株生物量的影响

[目的]了解卫星搭载对紫花苜蓿当代植株生物量的影响。[方法]3个品系的苜蓿种子搭载"实践八号"育种卫星进行飞行。返地后,对其植株茎粗、初级分枝数及单株当年生物量等指标进行测定。[结果]卫星搭载后,紫花苜蓿当代植株初级分枝数和单株生物量均显著增加,茎粗无显著变化。以高于(对照平均值+3倍标准差)为标准进行筛选,获得茎粗增加变异株2株,初级分枝增加变异株5株,单株生物量增加变异株12株。[结论]获得的变异株可用于苜蓿品种改良和新品种选育,但其有利变异能否稳定遗传有待于进一步研究。