Prolonged swimming performances of two as yet unnamed species of three-spined stickleback, Gasterosteus spp., were compared. The two fishes (not yet formally described, referred to here as benthic and limnetic) inhabit different niches within Paxton Lake, Texada Island, British Columbia, Canada, and are recent, morphologically distinct species. Limnetics had longer endurance during prolonged swimming than did benthics. The mean regression of the log 10 of fatigue time (F t , s) on swimming speed (U, standard length, L S s À1 ) for limnetics (log 10 F t ¼ 7Á03 À 0Á46U) had a similar slope, but a significantly higher intercept than that for benthics (log 10 F t ¼ 5Á55 À 0Á43U). Adult benthics were larger, heavier and deeper-bodied fish than limnetics. Limnetics, however, had a significantly greater pectoral fin edge:base ratio (mean AE S.E.: limnetics, 4Á58 AE 0Á43; benthics, 3Á63 AE 0Á27). In addition, limnetics had significantly lower drag coefficients (C D ) than benthics (limnetics, log 10 C D ¼ À0Á49log 10 R e þ 0Á66; benthics, log 10 C D ¼ À0Á26log 10 R e À 0Á30) where R e is the Reynolds number [(L S U (n À1 ), where U and n are swimming velocity and the kinematic viscosity of the water, respectively]. Compared to their ancestral form, the anadromous three-spined stickleback Gasterosteus aculeatus L., limnetics and benthics had significantly longer and shorter endurance times, respectively. In addition, both these fishes had significantly higher fast-start velocities than their ancestral form. Selection due to differential resource use may have lead to divergence of body form, and, therefore, of steady swimming performance. Therefore predation may be the selective force for the similar high escape performance in these two fishes. # 2005 The Fisheries Society of the British Isles

The leading cause of oral pain and tooth loss is from caries and their treatment include restoration using amalgam, resin, porcelain and gold, endodontic therapy and extraction. Resin composite restorations have grown popular over the last half a century because it can take shades more similar to enamel. Here, we discuss the history and use of resin, comparison between amalgam and resin, clinical procedures involved and finishing and polishing techniques for resin restoration. Although resin composite has aesthetic advantages over amalgam, one of the major disadvantage include polymerization shrinkage and future research is needed on reaction kinetics and viscoelastic behaviour to minimize shrinkage stress.

Threespine sticklebacks (Gasterosteus aculeatus L., form trachurus) with overripe, ovulated eggs have a hard 'berried' abdomen, easily distinguishable from the soft, smoothly distended abdomen of fish with normal ovulated eggs. The 'berried' fish weigh less and have a smaller GSI than 'nonberried' ovulated fish but the percentage water of their whole ovaries is the same. In contrast with 'nonberried' fish, 'berried' fish do not respond to male courtship. Overripe eggs are typical of those in other species with aggregation of cytoplasm and oil droplets at the animal pole. However, in contrast with normal ovulated eggs, they are larger, more transparent, and have a higher percentage water content although surrounded by much less fluid within the ovarian cavity. Overripe eggs do not appear to form a perivitelline space in fresh water. In 'berried' fish both the postovulatory corpora lutea (follicles) and ovarian epithelium (lining of the ovarian cavity) show histological signs of regression, in contrast with the histologically active condition of these tissues in fish with normal ovulated eggs. It is suggested that postovulatory corpora lutea play a role in maintenance of ovulated eggs in the ovarian cavity through secretion of steroid(s) which in turn stimulate the ovarian epithelium to secrete the bathing fluid of the eggs.

Key PointsQuestionIn a setting with low HIV-tuberculosis incidence, is repeated testing for latent tuberculosis infection (LTBI) cost-effective for managing individuals with HIV who have negative LTBI test results at baseline?FindingsIn this decision analytical model using a cost-effectiveness analysis, based on 3130 HIV-positive individuals in Hong Kong, China, a strategy of baseline LTBI testing followed by up to 3 subsequent annual tests could avert a similar proportion of new tuberculosis infections while incurring a lower cost compared with annually repeated testing. The strategy did not meet the willingness-to-pay threshold but would likely be cost-effective if the threshold were raised.MeaningThe findings suggest that less intense subsequent LTBI testing strategies may be effective and are likely cost-effective.