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1.
In this paper a new reactive mechanism based on perception-action bionics for multi-sensory integration applied to Un-manned Aerial Vehicles (UAVs) navigation is proposed.The strategy is inspired by the olfactory bulb neural activity observed inrabbits subject to external stimuli.The new UAV navigation technique exploits the use of a multiscroll chaotic system which isable to be controlled in real-time towards less complex orbits,like periodic orbits or equilibrium points,considered as perceptiveorbits.These are subject to real-time modifications on the basis of environment changes acquired through a Synthetic ApertureRadar (SAR) sensory system.The mathematical details of the approach are given including simulation results in a virtual en-vironment.The results demonstrate the capability of autonomous navigation for UAV based on chaotic bionics theory in com-plex spatial environments.  相似文献   

2.
喷雾:一种简便的拟南芥转化方法   总被引:1,自引:1,他引:1  
张森 《生物技术》2006,16(5):36-38
目的:建立一种改良的且操作更为简便可行的拟南芥转化方法。方法:用含有OD600等于0.8的农杆菌,5%蔗糖和0. 2 ml/L表面活性剂Silwet L-77的MS液体培养基喷洒正在发育的花器官即可实现基因转化。植物生长到高约4cm时进行转化,此时植物具有大量的花和极少数的果荚,可以得到比较高的转化效率。喷洒溶液后将植物用保鲜膜等材料包裹起来以保持湿度,可有利于转化。结果:得到了365棵转化植株,转化效率和花器官浸泡法的基本一致。结论:这种方法可适用于多种生态型的拟南芥植物转化,并且方便大规模的拟南芥植物的转化,便于人们快速获得带有T-DNA标记的植株或基因遗传互补工作的顺利开展。  相似文献   

3.
Precision agriculture: a challenge for crop nutrition management   总被引:3,自引:0,他引:3  
Robert  P. C. 《Plant and Soil》2002,247(1):143-149
Precision agriculture was initiated in the mid 1980s, using newly available technologies, to improve the application of fertilizers by varying rates and blends as needed within fields. Presently, the concept has been adapted to a variety of practices, crops, and countries. Its adoption varies significantly by cropping system, regions, and countries but it is progressively introduced or evaluated around the world. Several types of challenges limit a broader adoption: socio-economical, agronomical, and technological. Socio-economical barriers are principally costs and lack of skills. Agronomical challenges are lack of basic information, inadequate sampling and scouting procedures, absence of site-specific fertilizer recommendations, misuse of information, and lack of qualified agronomic services. There are multiple technological barriers that relate to machinery, sensor, GPS, software, and remote sensing. However, these barriers will be progressively lifted and precision agriculture will be a significant component of the agricultural system of the future. It offers a variety of potential benefits in profitability, productivity, sustainability, crop quality, food safety, environmental protection, on-farm quality of life, and rural economic development.  相似文献   

4.
This paper considers the extrema of the relative precision (R. P.), or the ratio of the variance of optimum allocation to that of proportional allocation in stratified sampling for a mean (=Y) or total (=Y) when there is a fixed cost C=conhch over L strata. The upper bound of R. P. is shown to be equal to unity, though the lower bound can be negative while approaching zero if the finite population size N→∞. Numerical results (cf. Table) when the upper bound of R. P. = 1 is attained are included for the cases L≦4 with various combinations of {Wh}, {ch} and a fixed cost C; these give the appropriate sample sizes (=np) determined for proportional sampling in the cases of finite populations of sizes N=5000, 10,000 respectively.  相似文献   

5.
Precision oncology implies customizing treatment to the unique molecular and biologic characteristics of each individual and their cancer. Its implementation is being facilitated by remarkable technological advances in genomic sequencing, as well as the increasing availability of targeted and immunotherapeutic drugs. Yet, next generation sequencing may be a disruptive technology in that its results suggest that classic paradigms for clinical research and practice are a poor fit with the complex reality encountered in metastatic malignancies. Indeed, it is evident that advanced tumors have heterogeneous molecular landscapes that mostly differ between patients. Traditional modes of clinical research/practice are drug centered, with a strategy of finding commonalities between patients so that they can be grouped together and treated similarly. However, if each patient with metastatic cancer has a unique molecular portfolio, a new patient-centered, N-of-one approach that utilizes individually tailored treatment is needed.  相似文献   

6.
1. This study highlights the use of waterbird communities as potential measures of river and floodplain health at a landscape scale. 2. The abundance and diversity of a waterbird community (54 species) was measured over 15 trips with four aerial and three ground counts per trip on a 300-ha lake in arid Australia. 3. Aerial survey estimates of individual species were significantly less precise (SE/mean) than ground counts across two (11–100 and > 1000) out of four abundance classes of waterbirds: 0–10, 11–100, 101–1000 and > 1000. Standard error/mean as a percentage decreased with increasing abundance from about 60% for the lowest abundance class to 18% for the largest abundance class. 4. Aerial survey estimates were negatively biased for species in numbers of less than 10 and greater than 5000 but unbiased compared to ground counts for other abundance classes. Aerial surveys underestimated numbers of waterbirds by 50% when there were 40 000 waterbirds. Three ground counts found about seven more waterbird species than four aerial surveys. One ground count took about 150 times longer than two aerial surveys and cost 14 times more. 5. Regression models were derived, comparing aerial survey estimates to ground counts for 31 of 36 species for which there were sufficient data. Aerial survey estimates were unbiased for most of these species (67%), negatively biased for six species and positively biased for one species. Estimates were negatively biased in species that occurred in small numbers or that dived in response to the aircraft. 6. River system health encompasses the state of floodplain wetlands. Waterbirds on an entire wetland or floodplain may be estimated by aerial survey of waterbirds; this is a coarse but effective measure of waterbird abundance. Aerial survey is considerably less costly than ground survey and potentially provides a method for measuring river and floodplain health over long periods of time at the same scale as river management.  相似文献   

7.
<正> We proposed a dynamic model identification and design of an H-Infinity (i.e.H_∞) controller using a LightweightPiezo-Composite Actuator (LIPCA).A second-order dynamic model was obtained by using input and output data, and applyingan identification algorithm.The identified model coincides well with the real LIPCA.To reduce the resonating mode that istypical of piezoelectric actuators, a notch filter was used.A feedback controller using the H_∞ control scheme was designed basedon the identified dynamic model; thus, the LIPCA can be easily used as an actuator for biomemetic applications such as artificialmuscles or macro/micro positioning in bioengineering.The control algorithm was implemented using a microprocessor, analogfilters, and power amplifying drivers.Our simulation and experimental results demonstrate that the proposed control algorithmworks well in real environment, providing robust performance and stability with uncertain disturbances.  相似文献   

8.
The lack of autonomous take-off and landing capabilities of bird-like flapping-wing aerial vehicles(BFAVs)seriously restricts their further development and application.Thus,combined with the current research results on the autonomous take-off and landing technology of unmanned aerial vehicles,four types of technologies are studied,including jumping take-off and landing technology,taxiing take-off and landing technology,gliding take-off and landing technology,and vertical take-off and landing(VTOL)technology.Based on the analytic hierarchy process(AHP)-comprehensive evaluation method,a fuzzy comprehensive evaluation model for the autonomous take-off and landing scheme of a BFAV is established,and four schemes are evaluated concretely.The results show that under the existing technical conditions,the hybrid layout VTOL scheme is the best.Furthermore,the detailed design and development of the prototype of a BFAV with a four-rotor hybrid layout are carried out,and the vehicle performance is tested.The results prove that through the four-rotor hybrid layout design,the BFAV has good autonomous take-off and landing abilities.The power consumption analysis shows that for a fixed-point reconnaissance mission,when the mission radius is less than 3.38 km,the VTOL type exhibits longer mission duration than the hand-launched type.  相似文献   

9.
10.
Aerial conidia of Metarhizium anisopliae (flavoviride) var. acridum strain IMI 330189 used for the inundative biological control of grasshoppers and locusts in sub-Saharan Africa are produced in a purpose-built facility at the International Institute for Tropical Agriculture in Benin using a standard, two-stage mass-production system. The yields average 31.1 g of dry conidia powder/kg of rice substrate, the production capacity is 300-350 kg of conidia/year and the production costs are estimated at US$21/100 g (the recommended dose for 1 ha). The production process parameters vary within narrow limits established during optimization, but the yield is characterized by a high level of variation over time. The incubation period and temperature are identified as key factors, although they account for less than 40% of the yield variation. The variation in conidial viability and contamination are correlated with several parameters, but none can adequately explain this variation. The handling time, a principal limiting factor, could be reduced by increasing the substrate quantity/unit of production. An awareness of these factors presents the opportunity to fine tune production, although the options for increasing or improving production efficiency are limited within the constraints of the system.  相似文献   

11.
A computer-simulation model (MELSIM) of a Meloidogyne-grapevine system is developed. The objective is to attempt a holistic approach to the study of nematode population dynamics by using experimental data from controlled environmental conditions. A simulator with predictive ability would be useful in considering pest management alternatives and in teaching. Rates of flow and interaction between the components of the system are governed by environmental conditions. Equations for these rates are determined by fitting curves to data from controlled environment studies. Development of the model and trial simulations have revealed deficiencies in understanding of the system and identified areas where further research is necessary.  相似文献   

12.
A microbioreactor immobilized with a synthase-type mutant enzyme, Endo-M-N175Q (glycosynthase) of endo-β-N-acetylglucosaminidase derived from Mucor hiemalis (Endo-M), was constructed and used for glycoconjugate synthesis. The transglycosylation was performed with a reaction mixture containing an oxazoline derivative of sialo complex-type glycoside (SG), which was prepared from a sialo complex-type glycopeptide SGP derived from hen egg yolk, as a glycosyl donor and N-Fmoc-N-acetylglucosaminyl-l-asparagine [Fmoc-Asn(GlcNAc)-OH] as an acceptor. The reaction mixture was injected into a glycosynthase microbioreactor at a constant flow rate. Highly efficient and nearly stoichiometric transglycosylation occurred in the microbioreactor, and the transglycosylation product was eluted from the other end of the reactor. The glycosynthase microbioreactor was stable and could be used repeatedly for a long time.  相似文献   

13.
目的研制一种新型的比格犬固定器。方法根据比格犬的体型大小设计出一种不锈钢固定架,将犬俯卧于固定架上,四肢穿过支撑体重的布垫糸在下方的横框上。结果此方法可长时间同时固定多条非麻醉状态的比格犬,适合于静脉推注或滴注给药以及多时间点静脉采血等操作。结论为比格犬研制出一种结构简单、操作方便的固定器。  相似文献   

14.
This paper presents a new series of AMS dates on ultrafiltered bone gelatin extracted from identified cutmarked or humanly-modified bones and teeth from the site of Abri Pataud, in the French Dordogne. The sequence of 32 new determinations provides a coherent and reliable chronology from the site’s early Upper Palaeolithic levels 5–14, excavated by Hallam Movius. The results show that there were some problems with the previous series of dates, with many underestimating the real age. The new results, when calibrated and modelled using a Bayesian statistical method, allow detailed understanding of the pace of cultural changes within the Aurignacian I and II levels of the site, something not achievable before. In the future, the sequence of dates will allow wider comparison to similarly dated contexts elsewhere in Europe. High precision dating is only possible by using large suites of AMS dates from humanly-modified material within well understood archaeological sequences modelled using a Bayesian statistical method.  相似文献   

15.
A semi-automatic system for pollen recognitionis studied for the european project ASTHMA. The goal of such a system is to provideaccurate pollen concentration measurements. This information can be used as well by thepalynologists, the clinicians or a forecastsystem to predict pollen dispersion. At first,our emphasis has been put on Cupressaceae, Olea, Poaceae and Urticaceae pollen types. The system is composed of two modules: pollengrain extraction and pollen grain recognition. In the first module, the pollen grains areobserved in light microscopy and are extractedautomatically from a pollen slide coloured withfuchsin and digitized in 3D. In the secondmodule, the pollen grain is analyzed forrecognition. To accomplish the recognition, itis necessary to work on 3D images and to usedetailed palynological knowledge. Thisknowledge describes the pollen types accordingto their main visible characteristerics and tothose which are important for recognition. Somepollen structures are identified like the porewith annulus in Poaceae, the reticulum in Oleaand similar pollen types or the cytoplasm inCupressaceae. The preliminary results show therecognition of some pollen types, likeUrticaceae or Poaceae or some groups of pollentypes, like reticulate group.  相似文献   

16.
We describe the development of a rapid colorimetric assay for soluble guanylate cyclase (sGC) activity adapted for a 96-well microplate. The assay greatly decreases the analysis time and cost over traditional methodologies based on radio- and immunoassays and high-performance liquid chromatography (HPLC) separations. The method does not demonstrate any significant interference with chemicals commonly used for sGC purification and reaction kinetics. The assay converts the inorganic pyrophosphate produced in the cyclase reaction to inorganic phosphate, which is then measured using a modified Fiske-Subbarow assay. We used the assay to compare the reaction kinetics of preparations of sGC from a commercial source with those from our lab with Mg(2+)-guanosine 5'-triphosphate (GTP) or Mn(2+)-GTP as a substrate. The commercial preparation was found to have a specific activity of around 1.5 micromol/min/mg, which is significantly lower than expected, as was the fold-activation upon addition of nitric oxide (NO). Our laboratory preparation had a higher specific activity that was consistent with results from HPLC assays. We determined that the human isoform of sGC is more active in the basal and NO forms with Mn(2)-GTP as a substrate than Mg(2+)-GTP, a feature more similar to rat lung sGC than the more commonly studied bovine lung.  相似文献   

17.
A new controlled production system to target heterologous proteins to cytoplasm or extracellular medium is described for Lactococcus lactis NCDO2118. It is based on the use of a xylose-inducible lactococcal promoter, P(xylT). The capacities of this system to produce cytoplasmic and secreted proteins were tested using the Staphylococcus aureus nuclease gene (nuc) fused or not to the lactococcal Usp45 signal peptide. Xylose-inducible nuc expression is tightly controlled and resulted in high-level and long-term protein production, and correct targeting either to the cytoplasm or to the extracellular medium. Furthermore, this expression system is versatile and can be switched on or off easily by adding either xylose or glucose, respectively. These results confirm the potential of this expression system as an alternative and useful tool for the production of proteins of interest in L. lactis.  相似文献   

18.
A model for cyanide species uptake by willow (Salix eriocephala L. var. Michaux) was developed to interpret data from hydroponic experiments quantitatively. While the potential for cyanide phytoremediation has been demonstrated modeling will aid in determining plant processes that contribute to cyanide transport and metabolism in willow and will target specific physiological parameters for field-scale phytoremediation design and optimization. The objective of the model development was to gain insight into the relative role of different processes with respect to dissolved free and iron-complexed cyanide transport and assimilation in plants and to determine rates at which these processes occur within the willow plant under the experimental conditions. A physiologically-based model describing plant uptake, transport, and metabolism of cyanide species was developed to reflect the processes that influence the movement of cyanide into and throughout the plant. Plant compartmentalization (root, stem, and leaf) corresponded to the level of detail in the data collected via hydroponic experiments. Inclusion of more detailed intra- and intercellular processes would create a model inconsistent with the macroscale nature of the data. Mass balances around each compartment were developed via kinetic representations for the mass transfer processes and were combined to form a model describing the fate of cyanide species within plant-water systems.  相似文献   

19.
A chemically defined diet is a useful tool for the study of nutritional physiology of organisms. We have developed such a diet for Camponotus carpenter ants to facilitate experiments on nutritional requirements of these ants. Worker colonies of Camponotus floridanus were fed with a chemically defined diet, containing all essential minerals, amino acids, vitamins, growth factors and sucrose in an agar matrix. After 13 weeks, neither the number of raised pupae, their dry weight, nor the mortality of workers in subcolonies fed with this diet differed significantly from control colonies fed with Bhatkar-Whitcomb-agar, in addition to cockroaches and diluted honey. Therefore, this diet is adequate for a normal brood production and a maximal growth rate of C. floridanus larvae, at least for a period of three months. This diet should be suitable for ants that are able to feed on agar-based food resources in general. Received 6 September 2006; revised 5 October 2006; accepted 18 October 2006. An erratum to this article is available at .  相似文献   

20.
Development of a high-frequency transforming vector for Aspergillus nidulans   总被引:18,自引:0,他引:18  
D J Ballance  G Turner 《Gene》1985,36(3):321-331
The pyr4 gene of Neurospora crassa, which codes for orotidine-5'-phosphate decarboxylase, is capable of transforming an Aspergillus nidulans pyrG mutant by chromosomal integration, despite low homology between the transforming DNA and the recipient genome. Integration of pFB6, a plasmid carrying pyr4 and capable of replication in Escherichia coli, was not observed at the pyrG locus. The efficiency of transformation was considerably enhanced (50-100 fold) by inclusion in the transforming vector of a 3.5-kb A.nidulans chromosomal sequence, ans1. Although this sequence was isolated on the basis of replicating activity in Saccharomyces cerevisiae, there was no evidence for such activity in A.nidulans. Part of the ans1 fragment appears to be reiterated in the A.nidulans genome, though it is not yet clear whether this is directly responsible for the high transformation frequency. The efficiency of transformation of A.nidulans by plasmids bearing ans1, using an improved protocol, was approx. 5 X 10(3) stable transformants per microgram of plasmid DNA.  相似文献   

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