Radar Studies of Internal Layers and Bottom Topography at Dome C, East Antarctica (Abstract only)

Extensive and detailed radar surveys at Dome C were conducted during the 1978–79 and 1979–80 austral field seasons by groups from the University of Wisconsin. Measurements were conducted within a 10 × 10 km grid centered approximately on the Dome C camp (some additional studies were carried out as far as 20 km from the camp) and involved profiling of internal layers and bottom topography. In addition, a new digital recording system for the radar was used during the first season and has yielded interesting results on internal layers near the French bore hole. Analysis of these data has produced a local map of bottom topography showing generally rough terrain. In particular, there is a rapid deepening of the bottom topography (about 500 m over 2 km) just grid south-west of the camp. Internal layers were found to be discontinuous on a scale of tens of meters. The deepest internal layers were detected at depths of about 2 500 m although a set of remarkable layer-like returns were observed about 50 to 100 m above the interpreted base of the ice. (It is not yet clear whether these returns represent reflections from layers internal to the ice or whether they are reflections and diffractions associated with the rough terrain.) In addition the processed digital records show an abrupt decrease in the reflection strength of internal layers at about 1 700 m. Because the digitally recorded data were collected at only one site, we reserve concluding that this observation is characteristic of the entire Dome C area until more of the photographically recorded data can be reduced.

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Radar Studies of Internal Layers and Bottom Topography at Dome C, East Antarctica (Abstract only)

Annals of Glaciology ◽

10.3189/s0260305500003086 ◽

1982 ◽

Vol 3 ◽

pp. 341-341

Author(s):

Kenneth C. Jezek ◽

Sion Shabtaie ◽

Charles R. Bentley

Keyword(s):

Bottom Topography ◽

Rough Terrain ◽

Digital Recording ◽

Internal Layers ◽

Abrupt Decrease ◽

University Of Wisconsin ◽

South West ◽

Recorded Data ◽

The University ◽

Local Map

Extensive and detailed radar surveys at Dome C were conducted during the 1978–79 and 1979–80 austral field seasons by groups from the University of Wisconsin. Measurements were conducted within a 10 × 10 km grid centered approximately on the Dome C camp (some additional studies were carried out as far as 20 km from the camp) and involved profiling of internal layers and bottom topography. In addition, a new digital recording system for the radar was used during the first season and has yielded interesting results on internal layers near the French bore hole.Analysis of these data has produced a local map of bottom topography showing generally rough terrain. In particular, there is a rapid deepening of the bottom topography (about 500 m over 2 km) just grid south-west of the camp. Internal layers were found to be discontinuous on a scale of tens of meters. The deepest internal layers were detected at depths of about 2 500 m although a set of remarkable layer-like returns were observed about 50 to 100 m above the interpreted base of the ice. (It is not yet clear whether these returns represent reflections from layers internal to the ice or whether they are reflections and diffractions associated with the rough terrain.) In addition the processed digital records show an abrupt decrease in the reflection strength of internal layers at about 1 700 m. Because the digitally recorded data were collected at only one site, we reserve concluding that this observation is characteristic of the entire Dome C area until more of the photographically recorded data can be reduced.

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150 CONCEPTION RATES OF FRESH AND FROZEN IN VIVO-PRODUCED MORULAE AND BLASTOCYSTS IN LACTATING DAIRY RECIPIENT COWS

Reproduction Fertility and Development ◽

10.1071/rdv23n1ab150 ◽

2011 ◽

Vol 23 (1) ◽

pp. 178

Author(s):

R. Sartori ◽

M. C. C. Mattos ◽

M. R. Bastos ◽

T. A. Oliveira ◽

J. N. Guenther ◽

...

Keyword(s):

Developmental Stage ◽

Linear Models ◽

Holstein Cows ◽

Embryo Viability ◽

University Of Wisconsin ◽

Frozen Embryos ◽

Conception Rates ◽

Recorded Data ◽

The University

The aim of this study was to evaluate conception rates of fresh or frozen embryos in the morula and blastocyst stages of development when transferred to lactating Holstein cows. During a 365-day period, 213 Day-7 embryos were produced by superovulation in lactating Holstein cows or nulliparous Holstein heifers and transferred to lactating Holstein cows synchronized with the Ovsynch protocol at the University of Wisconsin–Madison. After collection, embryos were evaluated and classified according to IETS standards. Subsequently, grades 1 and 2 embryos were conventionally frozen in ethylene glycol or transferred fresh to recipients on Day 7 of the cycle in the uterine horn ipsilateral to the corpus luteum. When there were more recipients than fresh embryos available, frozen embryos were thawed and transferred. Pregnancy diagnosis was performed on Days 30, 60, and 120 by ultrasound evaluations. Moreover, calving data were recorded. Data were analysed using generalized linear models and results are presented as least squares means ± standard errors. The average conception rates between 30 and 280 days of fresh (n = 45) and frozen (n = 168) embryos were similar (38.7 ± 7.3 and 29.4 ± 3.3%, respectively; P > 0.10). There was an interaction between treatment and embryo developmental stage (P < 0.10). The average conception rate was higher in fresh blastocysts (54.2 ± 12.8%) than fresh morulae (25.2 ± 5.1%) and cryopreserved embryos (P < 0.05). Moreover, there was no difference between conception rates of cryopreserved morulae and blastocysts (26.8 ± 3.6 and 32.1 ± 4.8%, respectively; P > 0.10). Embryo quality seems not to have influenced the conception rates of Holstein embryos (34.9 ± 3.3 and 32.9 ± 6.9% of grades 1 and 2, respectively; P > 0.10). We concluded, based on the results of this study, that cryopreservation of in vivo-produced embryos in Holstein donors did not substantially affect embryo viability and that the developmental stage of frozen embryos did not influence conception rates in lactating dairy recipients. Financial support from CNPq and FAPESP of Brazil.

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Some Biological Applications of High Voltage Electron Microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100051505 ◽

1974 ◽

Vol 32 ◽

pp. 298-299

Author(s):

Hans Ris

Keyword(s):

High Voltage ◽

Chromosome Structure ◽

Nerve Fibers ◽

Good Resolution ◽

High Voltage Electron Microscopy ◽

Voltage Electron ◽

University Of Wisconsin ◽

High Voltage Electron ◽

One Year ◽

The University

The High Voltage Electron Microscope Laboratory at the University of Wisconsin has been in operation a little over one year. I would like to give a progress report about our experience with this new technique. The achievement of good resolution with thick specimens has been mainly exploited so far. A cold stage which will allow us to look at frozen specimens and a hydration stage are now being installed in our microscope. This will soon make it possible to study undehydrated specimens, a particularly exciting application of the high voltage microscope.Some of the problems studied at the Madison facility are: Structure of kinetoplast and flagella in trypanosomes (J. Paulin, U. of Georgia); growth cones of nerve fibers (R. Hannah, U. of Georgia Medical School); spiny dendrites in cerebellum of mouse (Scott and Guillery, Anatomy, U. of Wis.); spindle of baker's yeast (Joan Peterson, Madison) spindle of Haemanthus (A. Bajer, U. of Oregon, Eugene) chromosome structure (Hans Ris, U. of Wisconsin, Madison). Dr. Paulin and Dr. Hanna are reporting their work separately at this meeting and I shall therefore not discuss it here.

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Ultrastructural characteristics of sporidia of Ustilago

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100155906 ◽

1989 ◽

Vol 47 ◽

pp. 786-787

Author(s):

Patricia N. Hackney

Keyword(s):

Electron Microscope ◽

Type System ◽

Tube Formation ◽

High Voltage Electron Microscopy ◽

Voltage Electron ◽

University Of Wisconsin ◽

Transmission Electron ◽

Ustilago Hordei ◽

Silene Alba ◽

The University

Ustilago hordei and Ustilago violacea are yeast-like basidiomycete pathogens ofHordeum vulgare and Silene alba respectively. The mating type system in both species of Ustilago is bipolar, with alleles, A,a, (U.hordei) and a1, a2 (U.violacea) at a single locus. Haploid sporidia maintain the asexual phase by budding, while the sexual phase is initiated by conjugation tube formation between the mating types during budding and conjugation.For observation of budding, sporidia were prepared by culturing the four types on YEG (yeast extract glucose) broth for 24 hours. After centrifugation at 5000g cells were either left unmated or mated in a1/a2,A/a combinations. The sporidia were then mixed 1:1 with 4% agar and the resulting 1mm cubes fixed in 8% gluteraldehyde and post fixed in osmium tetroxide. After dehydration and embedding cubes were thin sectioned with a LKB ultratome and photographed in a Zeiss 9s transmission electron microscope or in an AE1 electron microscope of MK11 1MEV at the High Voltage Electron Microscopy Center of the University of Wisconsin-Madison.

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