Group Tr Research Articles

Seasonality of estrus and ovulation is not modified by subjecting female Alpine goats to a tropical photoperiod

In order to determine whether seasonality of estrus and ovulatory activities was maintained in Alpine goats, when subjected to tropical photoperiodic variations, two groups of 9-month-old females ( n = 13 each) were used. After October, one group was kept for 33 consecutive months under a yearly photoperiodic cycle which simulated a temperate photoperiodic cycle (TE: 8 to 16 h of light per day) and the other group was kept under a tropical photoperiod (TR: 11 to 13 h of light per day) for the same duration. Estrus was monitored twice daily and ovulatory activity determined twice weekly by blood progesterone assays; during the last breeding season, ovulation rate was assessed at each cycle by laparoscopy. Seasonality of estrus and ovulatory activities appeared in both groups; the seasonal anestrus occurred during the same period under the TE and TR photoperiodic cycles (February to September for anestrus and March to September for anovulations). Females exposed to the TR photoperiodic cycle began their breeding season significantly earlier and with more variability than those exposed to the TE photoperiodic cycle, especially during the second season (37 and 17 days earlier for estrus and ovulations, respectively). The difference was attenuated at the beginning of the third season. The second breeding season was of significantly longer duration in group TR than in TE (49 and 31 days longer for estrus and ovulations, respectively). Duration of the third breeding season was not significantly different between groups. Durations of estrous behavior and ovulation rate were not different between groups. Estrus without associated ovulation and estrous cycles of short duration ( <17 days) appeared more frequently in group TR than in group TE, during the second, but not during the third season. It was concluded that seasonality in estrus and ovulatory activities of Alpine goats was not modified when females were exposed to a simulated tropical photoperiod.

Comparison of anthelmintic control programs for sheep in Virginia

Summary Haemonchus contortus is the most serious parasitic problem encountered by sheep producers in southwestern Virginia. Four anthelmintic control programs for grazing lambs were tested. Group TR received monthly sc injections of ivermectin (200 μg/kg of body weight). Group SI received the same dose of ivermectin at 0, 3, 6, 9, and 12 weeks after the start of the grazing season. Group SL was given levamisole (8 mg/kg, po) 0, 3, 6, 9, and 12 weeks after the start of the grazing season, and group TA received ivermectin (200 μg/kg) 0, 8, 16, 20, and 24 weeks after the beginning of grazing. None of the 4 programs provided satisfactory control of parasites as indicated by fecal egg counts and serum pepsinogen concentrations, although group-TR lambs gained significantly more weight than lambs in groups SI and TA. Group-TA lambs developed clinical haemonchosis in early August and required additional treatment at that time. These findings suggest that reliance on anthelmintics alone may not provide the most effective and economic control of parasitic infection.

Homotopy Groups and Torus Homotopy Groups

In recent years it has been found that the homotopy groups [9] can be made into a more powerful tool by the introduction of new operations. Two such have been defined and utilized: (i) every element of the fundamental group 7r, induces an automorphism of the n-dimensional homotopy group 7rX, so that 7rn becomes a group with operators; (ii) to every pair of elements a of Trm and ,3 of 7n there is defined an element a o fl the Whitehead product of a and i3, which belongs to the group 7r.m+?. It is shown in this paper that the homotopy groups of various dimensions and the operations (i) and (ii) can be welded together into a single group r which I call the torus homotopy Let us sketch briefly the process of unification. In the first place the algorithms (4.2) given by J. H. C. Whitehead [12] for calculating with the operation o are strongly reminiscent of rules for manipulating commutators. Moroever, in the only case in which the Whitehead product can be compared with the group operation-the case m = n = m + n -1 = 1-the Whitehead product a o $ is identical with the commutator [a, 1 = aca1 /-1. Furthermore M. Abe [1] has defined, for every integrer n > 2, a group Kn , containing subgroups isomorphic to wi and to 7rn, in which the operation of 7r on 7rn becomes an inner automorphism. Finally (cf ?4) the operation (i) may be described in terms of (ii) and Abe's description of (i) as an inner automorphism implies that a o ,3 is a commutator whenever either m or n is equal to 1. These facts suggested to me that the Whitehead product might be, without restriction on either m or n, an actual commutator operation in a suitably defined Thus I was led to define, for every positive integer r, a group Tr which I call the r-dimensional torus homotopy group [7]. This group contains subgroups isomorphic to 7n for every n 1.) The torus homotopy groups are defined in a natural way, closely resembling the definitions of the homotopy and Abe groups. As might be expected the Abe groups Kn, 2 < n < r, are also contained isomorphically in Tr (?10). The finite dimensional torus homotopy groups r, are contained isomorphically in one huge group r, the torus homotopy Perhaps the most remarkable consequence of the definition of these new groups is a disproof of the widely held belief that all of the non-Abelian character of a space is expressed in its fundamental group. In fact there are an infinite number of simply connected spaces which have non-Abelian torus homotopy groups. This state of affairs is an immediate consequence of the non-triviality of certain Whitehead products in a certain type of simply-connected space [12].

The Elite and the Elites

Individuals of high special personal belong to the elite of their group. Social ascendancy, however, is directed toward a position of high total social prestige. Such social prestige can be attained only when an individual holds an elite position in several elite groups that belong to elite categories. Some groups and categories are firxed (for instance, those of family and racial belongingness); others allow for horizontal and vertical social mobility. Individual efforts will, therefore, tend to make use of the freedom of changing groups, where such change is feasible. Where belonging to a group is fixed, trends for social improvement will take the form of gaining enhanced prestige for one's group and category. Intragroup prestige is largely achievement prestige, qualified, however, by the phenomenon of transfer of intergroup prestige and intercategorial prestige. This transfer is a cause of intragroup struggle and sometimes the cause of group collapse or shifting of group functions. Group str...