EXPERIMENTAL STUDIES OF ADAPTATION IN CLARKIA XANTIANA. I. SOURCES OF TRAIT VARIATION ACROSS A SUBSPECIES BORDER

Evolution ◽  
2004 ◽  
Vol 58 (1) ◽  
pp. 59 ◽  
Author(s):  
Vincent M. Eckhart ◽  
Monica A. Geber ◽  
Christopher M. McGuire
Keyword(s):  
Experimental Studies ◽  
Trait Variation ◽  
Clarkia Xantiana

scholarly journals EXPERIMENTAL STUDIES OF ADAPTATION IN CLARKIA XANTIANA. I. SOURCES OF TRAIT VARIATION ACROSS A SUBSPECIES BORDER

Evolution ◽  
2004 ◽  
Vol 58 (1) ◽  
pp. 59-70 ◽  
Author(s):  
Vincent M. Eckhart ◽  
Monica A. Geber ◽  
Christopher M. McGuire
Keyword(s):  
Experimental Studies ◽  
Trait Variation ◽  
Clarkia Xantiana

scholarly journals A willow drawing from 1786: the earliest depiction of intraspecific trait variation in plants?

2020 ◽  
Author(s):  
Ulrich E Stegmann
Keyword(s):  
Environmental Conditions ◽  
18Th Century ◽  
Elevation Gradient ◽  
Experimental Studies ◽  
Fourth Century ◽  
Trait Variation ◽  
Intraspecific Trait Variation ◽  
Bavarian Alps ◽  
In The Wild ◽  
Unidentified Species

Abstract Background and Aims The study of intraspecific trait variation (ITV) in plants has a long history, dating back to the fourth century BC. Its existence was widely acknowledged by the end of the 18th century, although systematic and experimental studies commenced only a century later. However, the historiography of ITV has many gaps, especially with regard to early observations and visual documents. This note identifies an early depiction of plant ITV. Methods The botanical works of Johann Wolfgang von Goethe (1749–1832), a German writer and naturalist, were subjected to close reading. This included all publications and unpublished sources related to botany between 1785 and 1832 (e.g. notes, drafts, diaries, letters, drawings). This material is accessible in the multi-volume historical-critical edition of Goethe’s studies in natural science (Leopoldina-Ausgabe). Key Results A diary entry from 9 September 1786 described changes in leaf morphology along an elevation gradient in the Bavarian Alps. The leaves of an unidentified species of willow (Spix sp.) and gentian (Gentiana sp.) were said to become narrower with increasing elevation; leaves also stood further apart on twigs, and the latter became thinner. A crude drawing of two willow twigs illustrated the differences. Goethe conjectured that the differences were due to environmental conditions. Conclusions Goethe’s notes were anecdotal, and it is unclear whether the observed plant individuals actually belonged to the same species. Nevertheless, the notes represent an early and clear articulation of the hypothesis that changes in environmental conditions can cause ITV in a natural plant population. The drawing may be the earliest visual record of environmentally caused plant ITV in the wild.

3-D reconstruction and analysis of mammalian mitotic spindle structure

1992 ◽  
Vol 50 (1) ◽  
pp. 578-579
Author(s):  
Kent McDonald ◽  
David Mastronarde ◽  
Rubai Ding ◽  
Eileen O'Toole ◽  
J. Richard McIntosh
Keyword(s):  
Cross Sections ◽  
Mitotic Spindle ◽  
Experimental Studies ◽  
Video Camera ◽  
Three Dimensions ◽  
Mitotic Spindles ◽  
Black And White ◽  
Reconstruction Methods ◽  
Spindle Structure ◽  
Tissue Culture Line

Mammalian spindles are generally large and may contain over a thousand microtubules (MTs). For this reason they are difficult to reconstruct in three dimensions and many researchers have chosen to study the smaller and simpler spindles of lower eukaryotes. Nevertheless, the mammalian spindle is used for many experimental studies and it would be useful to know its detailed structure.We have been using serial cross sections and computer reconstruction methods to analyze MT distributions in mitotic spindles of PtK cells, a mammalian tissue culture line. Images from EM negatives are digtized on a light box by a Dage MTI video camera containing a black and white Saticon tube. The signal is digitized by a Parallax 1280 graphics device in a MicroVax III computer. Microtubules are digitized at a magnification such that each is 10-12 pixels in diameter.

Effects of Attachment Styles on the Experience of Equity in Heterosexual Couples Relationships

2003 ◽  
Vol 50 (4) ◽  
pp. 298-310 ◽  
Author(s):  
Ina Grau ◽  
Jörg Doll
Keyword(s):  
Attachment Theory ◽  
Attachment Style ◽  
Intimate Relationships ◽  
Attachment Styles ◽  
Experimental Studies ◽  
The Other ◽  
Heterosexual Couples ◽  
Secure Attachment ◽  
Dependent Variables ◽  
Equity Ratio

Abstract. Employing one correlational and two experimental studies, this paper examines the influence of attachment styles (secure, anxious, avoidant) on a person’s experience of equity in intimate relationships. While one experimental study employed a priming technique to stimulate the different attachment styles, the other involved vignettes describing fictitious characters with typical attachment styles. As the specific hypotheses about the single equity components have been developed on the basis of the attachment theory, the equity ratio itself and the four equity components (own outcome, own input, partner’s outcome, partner’s input) are analyzed as dependent variables. While partners with a secure attachment style tend to describe their relationship as equitable (i.e., they give and take extensively), partners who feel anxious about their relationship generally see themselves as being in an inequitable, disadvantaged position (i.e., they receive little from their partner). The hypothesis that avoidant partners would feel advantaged as they were less committed was only supported by the correlational study. Against expectations, the results of both experiments indicate that avoidant partners generally see themselves (or see avoidant vignettes) as being treated equitably, but that there is less emotional exchange than is the case with secure partners. Avoidant partners give and take less than secure ones.

Exneriana – II – The Scientific Legacy of John E. Exner, Jr. 1Part of this paper was presented at the XIXth International Congress of Rorschach and Projective Methods, July 22–26, 2008, Louvain, Belgium.

2008 ◽  
Vol 29 (2) ◽  
pp. 81-107 ◽  
Author(s):  
Anne Andronikof
Keyword(s):  
Clinical Studies ◽  
Experimental Studies ◽  
Scientific Work ◽  
International Congress ◽  
Response Process ◽  
Scientific Legacy ◽  
Projective Test ◽  
Projective Methods ◽  
Comprehensive Picture ◽  
Complex Mechanisms

Based on an analysis of John Exner’s peer-reviewed published work from 1959 to 2007, plus a brief comment for an editorial in Rorschachiana, the author draws a comprehensive picture of the scientific work of this outstanding personality. The article is divided into three sections: (1) the experimental studies on the Rorschach, (2) the clinical studies using the Rorschach, and (3) Exner’s “testament,” which we draw from the last paper he saw published before his death (Exner, 2001/2002). The experimental studies were aimed at better understanding the nature of the test, in particular the respective roles of perception and projection in the response process. These fundamental studies led to a deeper understanding of the complex mechanisms involved in the Rorschach responses and introduced some hypotheses about the intentions of the author of the test. The latter were subsequently confirmed by the preparatory sketches and documents of Hermann Rorschach, which today can be seen at the H. Rorschach Archives and Museum in Bern (Switzerland). Exner’s research has evidenced the notion that the Rorschach is a perceptive-cognitive-projective test.

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