A Study on the Backward Design Instruction of Life Science I Defensive Action Unit

Postdoctoral positions in biology education research (BER) are becoming increasingly common as the field grows. However, many life science graduate students are unaware of these positions or do not understand what these positions entail or the careers with which they align. In this essay, we use a backward-design approach to inform life science graduate students of postdoctoral opportunities in BER. Beginning with the end in mind, we first discuss the types of careers to which BER postdoctoral positions lead. We then discuss the different types of BER postdoctoral positions, drawing on our own experiences and those of faculty mentors. Finally, we discuss activities in which life science graduate students can engage that will help them gauge whether BER aligns with their research interests and develop skills to be competitive for BER postdoctoral positions.

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The CM120 Biotwin: a high-contrast objective lens, optimum cryo-vacuum and improved EDX performance

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100139299 ◽

1995 ◽

Vol 53 ◽

pp. 584-585

Author(s):

Uwe Lücken ◽

Michael Felsmann ◽

Wim M. Busing ◽

Frank de Jong

Keyword(s):

Life Science ◽

Focal Length ◽

Objective Lens ◽

High Contrast ◽

Contrast Imaging ◽

X Ray ◽

Forming Mechanism ◽

Similar Image ◽

High Contrast Imaging ◽

Low Concentrations

A new microscope for the study of life science specimen has been developed. Special attention has been given to the problems of unstained samples, cryo-specimens and x-ray analysis at low concentrations.A new objective lens with a Cs of 6.2 mm and a focal length of 5.9 mm for high-contrast imaging has been developed. The contrast of a TWIN lens (f = 2.8 mm, Cs = 2 mm) and the BioTWTN are compared at the level of mean and SD of slow scan CCD images. Figure 1a shows 500 +/- 150 and Fig. 1b only 500 +/- 40 counts/pixel. The contrast-forming mechanism for amplitude contrast is dependent on the wavelength, the objective aperture and the focal length. For similar image conditions (same voltage, same objective aperture) the BioTWIN shows more than double the contrast of the TWIN lens. For phasecontrast specimens (like thin frozen-hydrated films) the contrast at Scherzer focus is approximately proportional to the √ Cs.

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X-ray mapping without STEM

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010017027x ◽

1994 ◽

Vol 52 ◽

pp. 508-509

Author(s):

Judith M. Brock ◽

Max T. Otten

Keyword(s):

Life Science ◽

Materials Science ◽

Chemical Elements ◽

Full Description ◽

Scanning System ◽

Elemental Distribution ◽

X Ray ◽

Transmission Electron ◽

Distribution Of Elements ◽

Made In

A knowledge of the distribution of chemical elements in a specimen is often highly useful. In materials science specimens features such as grain boundaries and precipitates generally force a certain order on mental distribution, so that a single profile away from the boundary or precipitate gives a full description of all relevant data. No such simplicity can be assumed in life science specimens, where elements can occur various combinations and in different concentrations in tissue. In the latter case a two-dimensional elemental-distribution image is required to describe the material adequately. X-ray mapping provides such of the distribution of elements.The big disadvantage of x-ray mapping hitherto has been one requirement: the transmission electron microscope must have the scanning function. In cases where the STEM functionality – to record scanning images using a variety of STEM detectors – is not used, but only x-ray mapping is intended, a significant investment must still be made in the scanning system: electronics that drive the beam, detectors for generating the scanning images, and monitors for displaying and recording the images.

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