Self-primed Research Articles

Differential Pollen Tube Success in Geranium caespitosum

Geranium caespitosum is self-compatible, yet selfing decreases both seed number and seed weight compared to outcrossing. A mechanism that inhibits the growth of self pollen would reduce losses in fitness from selfing and could be detected by comparing the number of pollen tubes entering ovules following self- and cross-pollination. Pistils receiving either self- or cross-pollen were each held for 2 h or 24 h and then prepared for fluorescence microscopy. After 2 h, fewer self- than cross-pollen tubes entered ovules. Differences between the number of self- and cross-pollen tubes entering ovules diminished after 24 h, indicating that many self-pollen tubes were delayed, but not excluded, from entering micropyles. Fluorescence microscopy confirmed that many pollen tubes are aborted in a specific region of transmitting tissue within the ovary. Thus, a labile mechanism favors cross-pollen but allows selfing when pollinators or neighboring plants are scarce.

Analysis of the leukemogenic properties of the bcr-v-abl and GM-CSF genes using a new retroviral vector.

The haemopoietic system consists of a hierarchy of cells that are produced throughout life from a small number of self renewing stem cells. Many of the molecules that regulate normal haemopoiesis have been defined and characterized by studying aspects of haemopoiesis that can occur in vitro under controlled conditions. Furthermore, our knowledge of the haemopoietic system has been supplemented by investigations of disease phenomena where haemopoiesis is perturbed. These include naturally occurring leukaemias in humans and those induced experimentally in laboratory animals.

Dimensions of adolescent identity

AbstractIt has been argued that the self‐concept is divided into two sub‐systems, one relating to personal and the other to social identities. The salience of these identities will depend upon the particular situation. How can the relationship between the individual's personal and social identities by conceptualized? To answer this question, Turner, Hogg, Oakes, Reicher and Wetherell (1987) proposed a hierarchical system of self‐categorization. At one level, social identities are determined though comparisons between groups, and at another level, personal identities are determined through comparisons between the self and other members of the ingroup. In the present study, adolescents described a number of self and others' identities in relevant social situations. Multidimensional scaling revealed three dimensions which subjects used to differentiate amongst the various identities. The first dimension separated peer group identities from ascribed social identities. The second dimension separated ingroups from outgroups and the third dimension differentiated personal identity from all other social stimuli. The latter dimensions therefore supported Turner et al's self‐categorization model.

Self inflicted injuries and the lunar cycle a preliminary report

Abstract Data on self inflicted injuries by poisoning in the Winnipeg, Canada area were compared to the lunar cycle. A statistically significant lunar periodicity was demonstrated for the females in the sample (p<.05) with a greater number of cases occurring during the first quarter and a smaller number occurring during the third quarter of the lunar cycle. The males did not show a lunar periodicity and showed a significantly different distribution than the females in the sample (p<.025). A significant correlation between periods in which a large number of self inflicted injuries occurred and the apogees and perigees of the moon, was found (p<.005). The possibility that factors such as weather with its accompanying electromagnetic processes and/or changes in the intensity of the geomagnetic field are mediating factors in a lunar phase effect on human behavior, is discussed.