The expressions of trypsin and chymotrypsin in the pyloric caeca of Atlantic salmon (Salmo salar L.) were studied in three experiments. Two internal (trypsin phenotypes, life stages) and three common external factors (starvation, feeding, temperatures) influencing growth rates were varied. Growth was stimulated by increased temperature and higher feeding rate, and it was depressed during starvation. The interaction between trypsin phenotype and start-feeding temperature affected specific activity of trypsin, but not of chymotrypsin. Trypsin specific activity and the activity ratio of trypsin to chymotrypsin (T/C ratio) increased when growth was promoted. Chymotrypsin specific activity, on the other hand, increased when there was a reduction in growth rate whereas fish with higher growth had higher chymotrypsin specific activity resulting in lower T/C ratio value. During a rapid growth phase, trypsin specific activity did not correlate with chymotrypsin specific activity. On the other hand, a relationship between specific activities of trypsin and chymotrypsin could be observed when growth declined, such as during food deprivation. Trypsin is the sensitive key protease under conditions favouring growth and genetically and environmentally affected, while chymotrypsin plays a major role when growth is limited or depressed. Trypsin specific activity and the T/C ratio value are shown to be important factors in the digestion process affecting growth rate, and could be applicable as indicators for growth studies of fish in captive cultures and in the wild, especially when food consumption rate cannot be measured.
Institutions must renew their emphasis on serving the needs of the individual. They should devote equal enthusiasm and resources to both recruitment and retention. Students are not likely to persist at an institution that does not seek to understand and fulfill individual student needs. Though students may be successfully recruited, those who lack awareness of institutional expectations and services, those who lack adequate preparation for college work, and, those who attend college only to fulfill the expectations of others, are likely to leave the institution if it fails to assist them during the early transitional period of their association. However, students who believe in the quality and responsiveness of the institution are far more likely to persist.
Generally, retention research exists in two forms. Either the study is designed to measure the effectiveness of retention programs implemented, or it seeks to establish cause and effect relationships between one or several variables and leaving school. This study presents the results of research which concentrated on the latter. It also sought to determine the differences between “persisters” and “leavers” in relation to their goals of attending college, and the effects of social and academic integration, associated with institutional commitment. Subpopulations including freshmen, transfer, continuing, graduated and former non- graduated students were studied. Implications of the research for student services are presented.
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