1,722,733 research outputs found
Plasticity and constraints on fatty acid composition in the phospholipids and triacylglycerols of Arabidopsis accessions grown at different temperatures
Get PDFAuthors are witht the Section of Integrative Biology, School of Biological Sciences, University of Texas at Austin, Austin, TX, 78712, USA -- Anushree Sanyal is witht the Department of Agronomy, College of Agricultural and Life Sciences, University of Wisconsin-Madison, Madison, WI, 53706, USABackground: Natural selection acts on multiple traits in an organism, and the final outcome of adaptive evolution may be constrained by the interaction of physiological and functional integration of those traits. Fatty acid composition is an important determinant of seed oil quality. In plants the relative proportions of unsaturated fatty acids in phospholipids and seed triacylglycerols often increases adaptively in response to lower growing temperatures to increase fitness. Previous work produced evidence of genetic constraints between phospholipids and triacylglycerols in the widely studied Arabidopsis lines Col and Ler, but because these lines are highly inbred, the correlations might be spurious. In this study, we grew 84 wild Arabidopsis accessions at two temperatures to show that genetic correlation between the fatty acids of the two lipid types is not expected and one should not influence the other and seed oil evolution and also tested for the adaptive response of fatty acids to latitude and temperature.
Results: As expected no significant correlations between the two lipids classes at either growing temperature were observed. The saturated fatty acids and erucic acid of triacylglycerols followed a significant latitudinal cline, while the fatty acids in phospholipids did not respond to latitude as expected. The expected plastic response to temperature was observed for all the triacylglycerol fatty acids whereas only oleic acid showed the expected pattern in phospholipids. Considerable phenotypic variation of the fatty acids in both the lipid types was seen.
Conclusion: We report the first evidence supporting adaptive evolution of seed triacylglycerols in Arabidopsis on a latitudinal cline as seen in other species and also their plastic adaptive response to growing temperature. We show that as expected there is no genetic correlations between the fatty acids in triacylglycerols and phospholipids, indicating selection can act on seed triacylglycerols without being constrained by the fatty acid requirements of the phospholipids. Phospholipid fatty acids do not respond to latitude and temperature as seen elsewhere and needs further investigation. Thus, the adaptive response of Arabidopsis and the genetic tools available for manipulating Arabidopsis, makes it an excellent system for studying seed oil evolution and also for breeding seed oil crops especially the Brassica species.Integrative [email protected]
An adaptive sensorimotor representation for reaching in the inferior parietal lobule of behaving monkeys
No full textPrimates use visual guidance in order to interact with their environment. For several decades, the inferior parietal lobule (IPL) has been known to contain neurons that respond to visual stimulation and motor behavior. While the neural activity during the reaching behavior has been shown in area 7a of IPL, reach related neural responses have never been tested in the dorsal prelunate area (DP) of IPL, which is adjacent to area 7a. Furthermore, neural response prior to the reaching movement has not been assessed in DP and area 7a. The first aim was to investigate the tuning properties of single neurons in DP and area 7a. The second aim was to assess the influence of eye position signal on reaching behavior. Third, the temporal evolution of sensorimotor transformation in area 7a and DP neurons was investigated by comparing neural signals throughout the reaching task. Lastly, cortical plasticity was tested using Fresnel prisms, which displaced the visual field by 12º in one of four directions: contralateral, ipsilateral, upwards, or downwards. Foveal and peripheral reaching tasks and reaching under perceptually distorted conditions were used. Neurons in area 7a and DP were observed to have differential tuning properties during the planning phase and the initiation of the reach, in addition to being selective for eye position and retinal visual stimulation. The response properties of the neurons in areas 7a and DP changed as the trial progressed in time. Differential preparatory and reach responses were observed during foveal and peripheral reaching. This implies that both eye position and retinal signals modulated the reach related responses. Alterations in spatial tuning of the neurons during all phases of the task were observed upon insertion of the Fresnel prisms imply that neural plasticity occurs as the cortex swiftly adapts to the mismatch between sensory input and motor output. The spatial tuning of the neurons did not merely compensate for the eye position shift implying that signals other than eye position affect the neural response during reaching. These combined results strongly support the claim that crucial aspects of sensorimotor transformation occur in areas 7a and DP.Ph.D.Includes bibliographical referencesIncludes vitaby Anushree Karni
supplementary_material – Supplemental material for Breast and Cervical Cancer Screening Among Medicaid Beneficiaries: The Role of Physician Payment and Managed Care
No full textSupplemental material, supplementary_material for Breast and Cervical Cancer Screening Among Medicaid Beneficiaries: The Role of Physician Payment and Managed Care by Lindsay M. Sabik, Bassam Dahman, Anushree Vichare, and Cathy J. Bradley in Medical Care Research and Review</p
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Multi-objective pareto optimal power quality improvement in distribution systems
No full textThe present study proposes a multi-objective optimized Electric Spring (ES) operation to improve the voltage regulation and overall power quality in a distribution system. A suitable controller has been designed for the ES implementing the Multi-objective artificial cooperative search (MOACS) optimization algorithm. The objectives are to enhance the system power factor, regulate the critical load voltage, and minimize the neutral current. The proposed technique provides satisfactory results with intermittent energy source also. The performance of MOACS has been compared with particle swarm optimization (PSO) and harmony search (HS) algorithms. It has been observed that the improvement in power factor and reduction of neutral current is much more with MOACS compared to PSO and HS. The power quality factors obtained with PSO are 0.9136, 0.9257, and 0.9146 for three different sets of loads, whereas, with HS, these values are 0.9072, 0.9324, and 0.8985. The same index improves to 0.9465, 0.9392, and 0.9307 with MOACS, which proves the efficacy of MOACS algorithm. The validation of the proposed scheme through real-time simulation confirms the reliability of this scheme
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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