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21.
Selena Humphreys Chris S. Elphick Carina Gjerdrum Margaret Rubega 《Journal of Field Ornithology》2007,78(2):152-158
ABSTRACT. Saltmarsh Sharp-tailed Sparrows ( Ammodramus caudacutus ) build ground nests, often with a closely-woven dome, in marshes that frequently flood during high tides. To test the hypothesis that domed nests help reduce the loss of eggs and chicks due to flooding or predation, we examined the characteristics and fate of 102 nests at sites along the coast of Connecticut. To test whether nest structure was tailored to suit microhabitat conditions, we also measured vegetation characteristics around nests. Finally, we conducted artificial nest-flooding experiments to determine whether removal of domes reduced egg retention during flooding. We found no significant effects of nest structure on breeding success or failure, and few significant correlations between nest structure and microhabitat. The height of nests above the ground, however, increased with vegetation height, supporting the hypothesis that nest construction is influenced by flooding, but not supporting the hypothesis that predation risk is important. Dome removal experiments showed that domes have a highly significant effect on the retention of eggs during flooding, suggesting that domes help eggs survive the regular tidal flooding of marshes. 相似文献
22.
Transcriptome sequencing of Hevea brasiliensis for development of microsatellite markers and construction of a genetic linkage map 总被引：1，自引：0，他引：1
24.
Chu-shu Zhu Chuan-yang Liu Xin-yuan Qiu Si-si Xie Wen-ying Li Lingyun Zhu Lv-yun Zhu 《Biotechnology and bioengineering》2020,117(7):2279-2294
Beyond their widespread application as genome-editing and regulatory tools, clustered regularly interspaced short palindromic repeats (CRISPR)-CRISPR-associated (Cas) systems also play a critical role in nucleic acid detection due to their high sensitivity and specificity. Recently developed Cas family effectors have opened the door to the development of new strategies for detecting different types of nucleic acids for a variety of purposes. Precise and efficient nucleic acid detection using CRISPR-Cas systems has the potential to advance both basic and applied biological research. In this review, we summarize the CRISPR-Cas systems used for the recognition and detection of specific nucleic acids for different purposes, including the detection of genomic DNA, nongenomic DNA, RNA, and pathogenic microbe genomes. Current challenges and further applications of CRISPR-based detection methods will be discussed according to the most recent developments. 相似文献
25.
Charles Gillott Will Mihkelson Maud Lanau Dave Cheshire Danielle Densley Tingley 《Journal of Industrial Ecology》2023,27(2):423-435
The transition toward a circular economy (CE) is key in decarbonizing the built environment. Despite this, knowledge of—and engagement with—CE philosophies remains limited within the construction industry. Discussion with practitioners reveals this to be contributed to by a lack of clarity regarding CE principles, with numerous organizations recommending implementation of differing and sometimes conflicting principles. In addition, a systematic assessment of how building designs consider CE is made difficult by the multiple design areas required to be considered and the large amount of design data required to do so. The absence of a systematic CE assessment causes a lack of comparability across designs, preventing benchmarking of CE practices in building design at present. This paper details the development of Regenerate, a CE engagement tool for the assessment of new and existing buildings, established in an effort to overcome the aforementioned barriers to the adoption of CE within the construction sector. A CE design workflow for the built environment is proposed, comprising four overarching circularity principles (Design for Adaptability; Design for Deconstructability; Circular Material Selection; Resource Efficiency) and contributing design actions. In addition to engaging stakeholders by enabling the assessment of building designs, the tool retrieves key data for further research. Information on completed design actions as well as recycling and waste metrics is collected to facilitate future CE benchmarking. “Bill of materials” data (i.e., material quantities) is also compiled, with this being key in material stock modeling research and embodied carbon benchmarking. 相似文献
26.
George Georgoulas Dimitris Gavrilis Ioannis G. Tsoulos Chrysostomos Stylios Joo Bernardes Peter P. Groumpos 《Biomedical signal processing and control》2007,2(2):69-79
Fetal heart rate (FHR) variations reflect the level of oxygenation and blood pressure of the fetus. Electronic Fetal Monitoring (EFM), the continuous monitoring of the FHR, was introduced into clinical practice in the late 1960s and since then it has been considered as an indispensable tool for fetal surveillance. However, EFM evaluation and its merit is still an open field of controversy, mainly because it is not consistently reproducible and effective. In this work, we present a novel method based on grammatical evolution to discriminate acidemic from normal fetuses, utilizing features extracted from the FHR signal during the minutes immediately preceding delivery. The proposed method identifies linear and nonlinear correlations among the originally extracted features and creates/constructs a set of new ones, which, in turn, feed a nonlinear classifier. The classifier, which also uses a hybrid method for training, along with the constructed features was tested using a set of real data achieving an overall performance of 90% (specificity = sensitivity = 90%). 相似文献
27.
Binding sites in proteins can be either specifically functional binding sites (active sites) that bind specific substrates with high affinity or regulatory binding sites (allosteric sites), that modulate the activity of functional binding sites through effector molecules. Owing to their significance in determining protein function, the identification of protein functional and regulatory binding sites is widely acknowledged as an important biological problem. In this work, we present a novel binding site prediction method, Active and Regulatory site Prediction (AR-Pred), which supplements protein geometry, evolutionary, and physicochemical features with information about protein dynamics to predict putative active and allosteric site residues. As the intrinsic dynamics of globular proteins plays an essential role in controlling binding events, we find it to be an important feature for the identification of protein binding sites. We train and validate our predictive models on multiple balanced training and validation sets with random forest machine learning and obtain an ensemble of discrete models for each prediction type. Our models for active site prediction yield a median area under the curve (AUC) of 91% and Matthews correlation coefficient (MCC) of 0.68, whereas the less well-defined allosteric sites are predicted at a lower level with a median AUC of 80% and MCC of 0.48. When tested on an independent set of proteins, our models for active site prediction show comparable performance to two existing methods and gains compared to two others, while the allosteric site models show gains when tested against three existing prediction methods. AR-Pred is available as a free downloadable package at https://github.com/sambitmishra0628/AR-PRED_source . 相似文献
28.
Computational models provide insight into the structure-function relationship in proteins. These approaches, especially those based on normal mode analysis, can identify the accessible motion space around a given equilibrium structure. The large magnitude, collective motions identified by these methods are often well aligned with the general direction of the expected conformational transitions. However, these motions cannot realistically be extrapolated beyond the local neighborhood of the starting conformation. In this article, the iterative cluster-NMA (icNMA) method is presented for traversing the energy landscape from a starting conformation to a desired goal conformation. This is accomplished by allowing the evolving geometry of the intermediate structures to define the local accessible motion space, and thus produce an appropriate displacement. Following the derivation of the icNMA method, a set of sample simulations are performed to probe the robustness of the model. A detailed analysis of beta1,4-galactosyltransferase-T1 is also given, to highlight many of the capabilities of icNMA. Remarkably, during the transition, a helix is seen to be extended by an additional turn, emphasizing a new unknown role for secondary structures to absorb slack during transitions. The transition pathway for adenylate kinase, which has been frequently studied in the literature, is also discussed. 相似文献
29.
探究学习是美国芝加哥大学教授施瓦布(Schwabjj)倡导的,通过学生自主参与获得知识的过程,培养学生的探究能力.建构主义认为知识应该是学生在一定的情境下,通过意义建构的方式获得的.这些是新课程标准带来的新教育教学理念.如何将探究性学习与基础知识的教学统一起来,让学生通过探究性学习来建构概念,是新课程改革中需要深入研究的问题. 相似文献
30.
湖北后河保护区珙桐的叶功能性状研究 总被引：1，自引：0，他引：1
该研究分析了珙桐群落主要叶功能性状之间的关系,比较了珙桐与林分其它优势树种以及珙桐Ⅰ级(胸径dbh<2.5cm)、Ⅱ级(dbh2.5～22.5cm)和Ⅲ级(dbh>22.5cm)3个龄级间叶功能性状上的差异.结果表明,珙桐的比叶面积(SLA)与单位质量的叶建成成本(CCm)、单位面积的叶建成成本(CCa)呈显著负相关(p<0.01).通过与林分其它优势树种相比较,珙桐具有较高的SLA、单位的质量的叶氮含量(Nmass);而CCm、CCa、单位面积的叶氮含量(Narea)却相对较低,这表明珙桐能较有效地利用有限资源.珙桐不同龄级的最大光合速率(Amax)、暗呼吸速率(Rd)、光补偿点(LCP)和光饱和点(LSP)均表现为珙桐Ⅲ级>Ⅱ级>Ⅰ级,而SLA则表现为Ⅰ级>Ⅱ级>Ⅲ级(p<0.05).尽管珙桐Ⅰ级在林下表现出较强的弱光适应能力,但在后期建成为Ⅱ级的过程中,叶片形态与光合生理特性均表现出对遮荫环境的不适应,光资源不足可能是珙桐种群更新受限的主要限制因子之一. 相似文献