Simulating transoceanic migrations of young loggerhead sea turtles: merging magnetic navigation behavior with an ocean circulation model.

Young loggerhead sea turtles (Caretta caretta) from eastern Florida, USA, undertake a transoceanic migration in which they gradually circle the Sargasso Sea before returning to the North American coast. Loggerheads possess a 'magnetic map' in which regional magnetic fields elicit changes in swimming direction along the migratory pathway. In some geographic areas, however, ocean currents move more rapidly than young turtles can swim.

Is the geographic distribution of nesting in the Kemp's ridley turtle shaped by the migratory needs of offspring?

Across the geographic area that a species uses for reproduction, the density of breeding individuals is typically highest in locations where ecological factors promote reproductive success. For migratory animals, fitness depends, in part, on producing offspring that migrate successfully to habitats suitable for the next life-history stage. Thus, natural selection might favor reproduction in locations with conditions that facilitate the migration of offspring.

Thermal effects in narrow linewidth single and two tone fiber lasers.

Significant effects from heating occur in both single and two tone fiber amplifiers. Single tone 1064 nm amplifiers have highest efficiency when the external environment surrounding the gain fiber is cold while 1064 nm two tone amplifiers co-seeded with broadband 1040 nm have maximum efficiency when the gain fiber is hot. It is shown experimentally that changes in the temperature of the core of the gain fiber have dramatic effects on the 1064 nm/1040 nm power distribution in the output of two tone amplifiers.

Enhancement of output power from narrow linewidth amplifiers via two-tone effect--high power experimental results.

Two-tone 1064 nm fiber amplifiers having both cold (16°C) and pump induced temperature zones co-seeded with narrow linewidth 1064 nm and broad linewidth 1040 nm photons have been shown to have a power enhancement factor between 1.6 and 1.8 relative to the optimum single-tone 1064 nm amplifier while maintaining an efficiency of 65% or greater.

A theoretical treatment of two approaches to SBS mitigation with two-tone amplification.

A technique that employs two seed signals for the purpose of mitigating stimulated Brillouin scattering (SBS) effects in narrow-linewidth Yb-doped fiber amplifiers is investigated theoretically by constructing a self-consistent model that incorporates the laser gain, SBS, and four-wave mixing (FWM). The model reduces to solving a two-point boundary problem consisting of an 8x8 system of coupled nonlinear differential equations. Optimal operating conditions are determined by examining the interplay between the wavelength separation and power ratio of the two seeds.

Theory of electronically phased coherent beam combination without a reference beam.

The first theory for two novel coherent beam combination architectures that are the first electronic beam combination architectures that completely eliminate the need for a separate reference beam are presented. Detailed theoretical models are developed and presented for the first time.