Metamorphosis of the Pedunculate Barnacle Capitulum mitella Linnaeus, 1758 (Cirripedia: Scalpelliformes)

In this paper, metamorphosis of laboratory-reared cyprids of the pedunculate cirripede, Capitulum mitella was successfully induced. A timeline and a detailed description of morphological events during metamorphosis were derived from light microscopy and scanning electron microscopy analyses. The metamorphic process of cyprids involves five main events. (1) Triggering of metamorphosis: after 0–6 h of reagent exposure, the epidermis ventral to the compound eyes gradually invaginates. (2) Invagination and separation of epidermis: after 6–36 h, the invagination bypasses the compound eyes, the cypris epidermis separates slightly from the carapace and the nauplius eye gradually migrates ventrally. (3) Formation of juvenile rudiment: after 36–72 h, the metamorphosing specimen shape slightly resembles that of a juvenile. (4) Shedding of thoracopodal exuvium: after 72–96 h, the cyprid finally sheds the thoracopodal exuvium and metamorphoses into a juvenile barnacle. (5) Early development of juvenile barnacle: the juvenile shed the cirrum cuticle for the first, second, third and fourth time at 1.5–2, 1.5–2, 4–5 and 5–6 days, respectively. The newly formed juvenile completely assumes the shape and armature of all shell-plates found in adult barnacle. Rostro-carnal length of the juvenile is 240–260 μm. Tergum, scutum and upper latus are paired, and carina and rostrum are unpaired. Uniform circular depressions are dispersed on the surface of the tergum, scutum and carina. The rostrum and upper latus, which have the shape of small triangle, are not clear. The entire surface of the peduncle is covered with convoluted cuticular ridges. The metamorphosis of C. mitella is similar to that of Lepas.

Influences of Target Surface Roughness on Impingement Jet Array Heat Transfer: Part 2 — Effects of Roughness Shape, and Reynolds Number

The present investigation considers the effects of special roughness patterns on impingement target surfaces to improve the effectiveness and surface heat transfer augmentation levels of impingement jet array cooling. This investigation utilizes various sizes, distributions, shapes, and patterns of surface roughness elements for impingement cooling augmentation. The surface roughness shapes considered here are rectangle and triangle, in combination with larger rectangular pins. Configurations considered include: (i) arrays of small rectangular roughness, (ii) arrays of small triangle roughness, (iii) combinations of small rectangle roughness and large pins together, and (iv) combinations of small triangle roughness and large pins together. Tests are performed at impingement jet Reynolds numbers of 900, 1500, 5000, and 11000. Local and overall impingement cooling performance depends upon the shape of the roughness elements, as well as upon the jet Reynolds number. Depending upon the magnitude of jet Reynolds number, different behavior and trends are observed for the arrays of small rectangle roughness, compared with arrays of small triangle roughness. These differences are related to the abilities of the two different roughness shapes to generate different distributions of local mixing and vorticity at different length and time scales. Overall, results demonstrate the remarkable ability of target surface roughness to produce increased surface heat transfer augmentation levels of impingement jet array cooling, relative to target surfaces which are smooth.

The Effect of Goal Setting Difficulty on Serving Success in Table Tennis and the Mediating Mechanism of Self-regulation

The Effect of Goal Setting Difficulty on Serving Success in Table Tennis and the Mediating Mechanism of Self-regulationGoal setting difficulty has been shown to contribute to athletic performance (Burton et al., 2000). However, the potential mediating mechanism of goal difficulty on performance is unclear. Therefore, the purpose of this study was to verify the effect of goal setting difficulty on serving success in table tennis, and determine if self-regulation is the mediating variable. The current study used serving success within a one minute period as the task, and the "Athlete's Self-regulation in Motor Learning" as the measurement tool. The experiment was designed as a 3 (serving frequency: 20/min, 23/min, and 26/min) x 2 (serving placement: left "small triangle", and right "small triangle") model. Participants (N = 60) in the current study were students from a physical education school. These participants were randomly assigned into the experimental and control groups. After the intervention, differences in self-regulation (p < 0.001) and serving success (p < 0.05) between the experimental and control groups were significant. For the experimental groups, there was a significant difference in self-regulation (p < 0.001) and serving success (p < 0.05) before and after the experiment. Serving frequency had a main effect on self-regulation (F (5, 24) = 12.398, p < 0.01) and serving success (F (5, 24) = 37.601, p < 0.001). Moderately difficult goal setting contributed to athletic performance. Regression analysis using bootstrapping methods revealed that self-regulation partially mediated the relationship between the two.