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A numerical model is developed to compare the performances of mooring materials for a gravity cage system. At first, a small-scale model is built and it is validated by the previous experiments. With the same method, a full-scale gravity cage model is built to study the performance of different mooring materials. Link elements are used to model the wire ropes to consider the weight, and nonlinear spring elements are used to model the composite fibre ropes to consider the nonlinear stiffness. High-tenacity polyester multifilament fibre has the best performance. It can reduce the average value and amplitude of the mooring forces, which also contributes to reducing the stress concentration on the collar. At last, the mooring forces at specific locations in Portugal are calculated and the distributions of mooring force amplitudes are analysed. • A numerical model is developed to compare the performances of mooring materials for a gravity cage system. • A small-scale model is built and it is validated by the previous experiments. • With the same method, a full-scale gravity cage model is built to study the performance of different mooring materials. • Wire ropes and composite fibre ropes are studied and are modelled considering the nonlinear stiffness. • High-tenacity polyester multifilament fibre has the best performance as it can reduce the mooring forces. [ABSTRACT FROM AUTHOR]

A numerical model is developed to calculate the mooring forces and cage volumes for a gravity cage system. The collar, nets, bottom ring and mooring system are all modelled by line elements due to the slender structure. The effect of structural parameters on the cage capacity and mooring forces is evaluated in a sensitivity analysis, to provide knowledge in the design phase of a fish cage. Heaver sinkers and nets with smaller solidity are preferred to prevent the volume reduction of fish cages but they lead to a larger mooring force or an increase in the probability of fish escaping. Linear wave theory is applied. Short waves increase the mean value of the mooring force and higher waves result in a larger amplitude of the mooring force. It is also found that short waves can change the shape of the nets while the shape of the cage subjected to long waves almost keeps constant as the one under uniform flow, which obtains a good agreement as previous experiments. • A numerical model to calculate the mooring forces and cage volumes for a gravity cage is developed and validated. • Sensitivity studies determine the influence of various governing parameters on the dynamic response. • Effects studied are the elasticity of the net, weight of the bottom ring and the net solidity. • Short waves reduce the cage volume and the amplitudes of mooring forces, but increases the the mooring force. • The average value of mooring forces and cage volumes approach those in uniform flow when the wave period increases. [ABSTRACT FROM AUTHOR]

Experiments are conducted in a flume to study the mooring forces and motions of a gravity cage in regular waves. Cage models are built with hollow pipes and nets. Mooring forces and cage motions including surge, heave and pitch are measured. With the increase of the wavelength, the mooring force, surge and heave increase while the rate of increase gradually slows down until stops. On the other hand, under short waves, the pitch increases with the decrease of the wavelength. In addition, the cage does not finish a cycle of motion before the next peak arrives, which leads to a reduction in mooring forces and motion in all directions. With the observation of overtopping, it can be concluded that the motion of the cage goes through three phases with the growth of the wavelength. Under short waves, the cage does not have enough time to complete a cycle of motion and overtopping occurs. With the increase of the wavelength, the motion of the cage starts to follow the waves and overtopping disappears. When the wave is long enough, the cage is pulled into the water by the mooring line and overtopping occurs again. • Experiments are conducted in a flume to study the mooring force and motion of a gravity cage subjected to regular waves. • A light and strong frame is designed to fix a motion sensor above the collar. Mooring forces and cage motions are measured. • Under short waves, the cage does not have enough time to complete a cycle of motion and overtopping occurs. • With the increase of the wavelength, the motion of the cage starts to follow the waves and overtopping disappears. • When the wave is long enough, the cage is pulled into the water by the mooring line and overtopping occurs again. [ABSTRACT FROM AUTHOR]

Experiments are conducted in a flume to study the motions and the wake behind a circular gravity cage under linear waves. The gravity cage model is built with high-density polyethylene pipes and nylon nets. Wave heights and periods are measured by wave gauges both upstream and downstream. Supports are used above the flume to fix the gauges and to connect the cage model. It is found that the cage behaves differently under short and long waves. The relative motion between the floating cage and the water surface is large under short waves. It can be observed clearly how the short waves pass over the collar. On the other hand, the collar just rides on long waves without apparent relative motion. The wave height is reduced when short waves pass the cage, while the wave height reduction under long waves is too small to be measured. The effect of the cage diameter, the collar cross-section, the bottom weight and biofouling is also studied. Generally speaking, larger and heavier cages have a greater impact on waves. [ABSTRACT FROM AUTHOR]

Transcription repression is emerging as a key regulatory mechanism underlying cell fate specification and body patterning in both animals and plants. In animals and fungi, the Groucho (Gro)/Tup1 family co-repressors generate the repressed chromatin state in genetic loci that control major developmental decisions ranging from dorsal–ventral patterning to eye development. In higher plants, information about the Gro/Tup1 co-repressors is beginning to emerge. Several recent publications have revealed both conserved and unique structural and mechanistic features of plant Gro/Tup1 co-repressors, including LEUNIG (LUG), TOPLESS (TPL) and WUSCHEL-INTERACTING PROTEINS (WSIPs). These co-repressors regulate key developmental processes in floral organ identity specification, embryo apical-basal fate determination, and stem cell maintenance at the shoot apex. [Copyright &y& Elsevier]

• Stolons and rhizomes are specialized stems for vegetative reproduction in many plant species. • Stolons and rhizomes enhance survival as well as invasiveness. • Diploid wild strawberry , Fragaria vesca , is emerging as a model system to study stolon. • In strawberry axillary meristem, GA, DELLA, as well as CO-FT-SOC1 regulate stolon formation. • The BLADE-ON-PETIOLE gene regulates leaf sheath-to-blade ratio to help rhizomes grow in soil. Stolons and rhizomes are modified stems for vegetative reproduction. While stolons grow above the ground, rhizomes grow beneath the ground. Stolons and rhizomes maintain the genotypes of hybrids and hence are invaluable for agricultural propagation. Diploid strawberry is a model for studying stolon development. At the axillary meristems, gibberellins and MADS box gene SOC1 promote stolon formation, while the DELLA repressor inhibits stolon development. Photoperiod regulates stolon formation through regulating GA biosynthesis or balancing asexual with sexual mode of reproduction in the axillary meristems. In rhizomatous wild rice, the BLADE-ON-PETIOLE gene promotes sheath-to-blade ratio to confer rhizome tip stiffness and support underground growth. Together, this review aims to encourage further investigations into stolon and rhizome to benefit agriculture and environment. [ABSTRACT FROM AUTHOR]