Equine conceptus development : a mini review

Many aspects of early embryonic development in the horse are unusual or unique; this is of scientific interest and, in some cases, considerable practical significance. During early development the number of different cell types increases rapidly and the organization of these increasingly differentiated cells becomes increasingly intricate as a result of various inter-related processes that occur step-wise or simultaneously in different parts of the conceptus (i.e., the embryo proper and its associated membranes and fluid). Equine conceptus development is of practical interest for many reasons. Most significantly, following a high rate of successful fertilization (71-96%) (Ball, 1988), as many as 30-40% of developing embryos fail to survive beyond the first two weeks of gestation (Ball, 1988), the time at which gastrulation begins. Indeed, despite considerable progress in the development of treatments for common causes of sub-fertility and of assisted reproductive techniques to enhance reproductive efficiency, the need to monitor and rebreed mares that lose a pregnancy or the failure to produce a foal, remain sources of considerable economic loss to the equine breeding industry. Of course, the potential causes of early embryonic death are numerous and varied (e.g. persistent mating induced endometritis, endometrial gland insufficiency, cervical incompetence, corpus luteum (CL) failure, chromosomal, genetic and other unknown factors (LeBlanc, 2004). However, the problem is especially acute in aged mares with a history of poor fertility in which the incidence of embryonic loss between days 2 and 14 after ovulation has been reported to reach 62-73%, and in which embryonic death is due primarily to embryonic defects rather than to uterine pathology (Ball et al., 1989; Carnevale & Ginther, 1995; Ball, 2000).

Universal Museum - universal language? Art historian - curator

Marshal McLuhan’s prophetic vision of the global village is about to be realized. If we are aware of the fact that mass communication reduces the dimensions of our world and makes it more unified and universal, we should take this into consideration when planning the Universal Museum and the language that should be used in it. As curators, educators and museum staff we should not ignore the fact that the spectator/viewer is drawn to the exhibits not only by their own merit, but also guided and assisted by verbal messages, i. e. Labels, brochures. Catalogues etc. Hence, the crucial question is what we, the museologists, use as a means of communication when preparing for a Universal Museum. Should we use pictorial semiotics? This may be a partial solution, which is mainly restricted to objects that can be manipulated and moved by the visitor, as is the case in most of the technological museums. But since the range of objects on display at museums is vast and varied - fine art, archaeological finds, ethnographic objects etc., it may not be the answer to the whole spectrum of exhibits. Dr. Ludwig Lazarus Zamenhof, being an optimist, hoped that by introducing Esperanto to the multi-lingual world population, humanity would be able to bridge and diminish the gap of linguistic differences, thus creating a better understanding between the international communities. Unfortunately this vision was not realized. Esperanto was and still is an utopian and esoteric phenomenon. The barriers between nations still exist although, as mentioned earlier, mass media do help, in some ways, to reduce them.