Sexual abuse risk in sport: Testing the ‘stage of imminent achievement’ hypothesis

The purpose of this study was to assess the hypothetical model outlined by Brackenridge and Kirby in IRSS in 1997 (32(4): 407-418) which suggested that athlete susceptibility to grooming and sexual abuse in sport coincides with a defined stage of athletic development just prior to peak success: this period they called the ‘stage of imminent achievement’ (SIA). The model was assessed by investigating 83 cases of criminally-defined child sexual abuse within the sport context that had been reported in the print media over a period of 15 years. SIA-related hypotheses were examined in relation to athlete performance level, sex and early- and late-specialisation sport types. The majority of cases of child abuse in the sample occurred below the SIA for both males and females and with sexually abused males being three times more likely to be aged below the SIA than their female athlete victim counterparts. Age below the SIA thus appears to be a stronger predictor of the timing of sexual abuse among male athletes than females: this suggests that much more research is needed on both age and gender differences in sport-related sexual victimisation. Several limitations of the data are discussed. It is recommended that the SIA be reconceived as both a relational and a developmental construct and examined more closely in relation to the increased dependence of the athlete on their coach just as they approach a performance goal

Classifying multispectral data by neural networks

Several energy functions for synthesizing neural networks are tested on 2-D synthetic data and on Landsat-4 Thematic Mapper data. These new energy functions, designed specifically for minimizing misclassification error, in some cases yield significant improvements in classification accuracy over the standard least mean squares energy function. In addition to operating on networks with one output unit per class, a new energy function is tested for binary encoded outputs, which result in smaller network sizes. The Thematic Mapper data (four bands were used) is classified on a single pixel basis, to provide a starting benchmark against which further improvements will be measured. Improvements are underway to make use of both subpixel and superpixel (i.e. contextual or neighborhood) information in tile processing. For single pixel classification, the best neural network result is 78.7 percent, compared with 71.7 percent for a classical nearest neighbor classifier. The 78.7 percent result also improves on several earlier neural network results on this data

Storage hexamer utilization in Manduca sexta

In preparing for metamorphosis insects store in their hemolymph and fat bodies a major nutrient reserve of 500-kDa hexamerins. At least three hexamerins serve this function in Lepidoptera, including arylphorin (ArH) and two high methionine proteins (M-MtH and V-MtH). Six day-old adults of Manduca sexta Abbreviation: / ArH: arylphorin M-MtH: moderately high methionine hexamerin PBS: phosphate buffered saline V-MtH: very high methionine hexamerin Vg: vitellogeni

Storage hexamer utilization in two lepidopterans: differences correlated with the timing of egg formation

Most insects produce two or more storage hexamers whose constituents and developmental profiles are sufficiently different to suggest specialization in the ways that they support metamorphosis and reproduction. Hexamerin specializations are compared here in the Cecropia moth (Hyalophora cecropia), which produces eggs during the pupal-adult molt, and the Monarch butterfly (Danaus plexippus), which produces eggs under long-day conditions after adult eclosion. In both sexes of both species, reserves of arylphorin (ArH) were exhausted by the end of metamorphosis. In Cecropia, the same was true for the high-methionine hexamerins, V-MtH and M-MtH. But in short day Monarch females 20–30% of the pupal reserves of V-MtH and M-MtH survived metamorphosis, persisting until long-day conditions were imposed to stimulate egg formation. Differences in storage sites have been documented in other lepidopterans, with MtH reserves being found primarily in fat body protein granules and the ArH reserve being found primarily in the hemolymph. Similar differences could explain how a fraction of the MtH's, but not of ArH, escapes utilization during metamorphosis in a species with post-eclosion egg formation. No differences in utilization schedules were detected between V- and M-MtH, despite divergent compositions and antigenic reactivity

Activin promotes oocyte development in ovine preantral follicles in vitro

Activins have been implicated as important regulating factors for many reproductive processes. The aim of this study was to determine the effect of activin A on the development of ovine preantral follicles in vitro. Mechanically isolated preantral follicles (161 ± 2 microm) were cultured for 6 days in the presence of human recombinant activin A (0, 10 and 100 ng/ml). Half of the medium was replaced every second day and follicle diameters were measured. Conditioned medium was subsequently analysed for oestradiol content using a delayed enhancement lanthanide fluorometric immunoassay (DELFIA). At the end of the culture period, follicles were fixed and processed for histology, after which oocyte diameter and granulosa cell death were measured. There was significant follicle growth over 6 days in all groups (p < 0.001). Activin, at both concentrations, increased follicle growth over control levels by Day 6 (p < 0.05). Oocyte diameters were also significantly increased by Day 6 of culture in all groups (p < 0.05), with 100 ng/ml activin increasing oocyte diameter over control levels (p < 0.05). Activin, at both concentrations, increased oestradiol production on Day 2 of culture, but this increase was not sustained during the culture period. Moreover, activin did not have any effect on antrum formation or follicle survival. In conclusion, activin promoted ovine preantral follicle and oocyte growth in vitro, but did not accelerate follicle differentiation over a six-day culture period. These results support a paracrine role for activin A during early oocyte and follicular development