White-crowned sparrows tutored with syllable pairs can produce full songs

Journal ArticleDuring their 'sensitive period', young songbirds develop an 'acquired template', representing a memory of the song(s) that it hears. Later, during the sensorimotor phase, birds use this template to evaluate, via auditory feedback, their vocalizations

Gas Accretion and Star Formation Rates

Cosmological numerical simulations of galaxy evolution show that accretion of metal-poor gas from the cosmic web drives the star formation in galaxy disks. Unfortunately, the observational support for this theoretical prediction is still indirect, and modeling and analysis are required to identify hints as actual signs of star-formation feeding from metal-poor gas accretion. Thus, a meticulous interpretation of the observations is crucial, and this observational review begins with a simple theoretical description of the physical process and the key ingredients it involves, including the properties of the accreted gas and of the star-formation that it induces. A number of observations pointing out the connection between metal-poor gas accretion and star-formation are analyzed, specifically, the short gas consumption time-scale compared to the age of the stellar populations, the fundamental metallicity relationship, the relationship between disk morphology and gas metallicity, the existence of metallicity drops in starbursts of star-forming galaxies, the so-called G dwarf problem, the existence of a minimum metallicity for the star-forming gas in the local universe, the origin of the alpha-enhanced gas forming stars in the local universe, the metallicity of the quiescent BCDs, and the direct measurements of gas accretion onto galaxies. A final section discusses intrinsic difficulties to obtain direct observational evidence, and points out alternative observational pathways to further consolidate the current ideas.Comment: Invited review to appear in Gas Accretion onto Galaxies, Astrophysics and Space Science Library, eds. A. J. Fox & R. Dav\'e, to be published by Springe

Field and Laboratory Studies Provide Insights into the Meaning of Day-Time Activity in a Subterranean Rodent (Ctenomys aff. knighti), the Tuco-Tuco

South American subterranean rodents (Ctenomys aff. knighti), commonly known as tuco-tucos, display nocturnal, wheel-running behavior under light-dark (LD) conditions, and free-running periods >24 h in constant darkness (DD). However, several reports in the field suggested that a substantial amount of activity occurs during daylight hours, leading us to question whether circadian entrainment in the laboratory accurately reflects behavior in natural conditions. We compared circadian patterns of locomotor activity in DD of animals previously entrained to full laboratory LD cycles (LD12∶12) with those of animals that were trapped directly from the field. In both cases, activity onsets in DD immediately reflected the previous dark onset or sundown. Furthermore, freerunning periods upon release into DD were close to 24 h indicating aftereffects of prior entrainment, similarly in both conditions. No difference was detected in the phase of activity measured with and without access to a running wheel. However, when individuals were observed continuously during daylight hours in a semi-natural enclosure, they emerged above-ground on a daily basis. These day-time activities consisted of foraging and burrow maintenance, suggesting that the designation of this species as nocturnal might be inaccurate in the field. Our study of a solitary subterranean species suggests that the circadian clock is entrained similarly under field and laboratory conditions and that day-time activity expressed only in the field is required for foraging and may not be time-dictated by the circadian pacemaker

Timed, sustained, attention-demanding performance reorganizes or dampens multiple circadian rhythms.

Gritton et al (2009) reported that rats practicing daily a sustained attention task (SAT) at ZT4 exhibit inverted activity patterns, such that the majority of activity as measured by movement occurs during the light phase. This shift was not apparent in animals trained under several other control conditions, including an operantly similar simple reaction task that requires less cognitive vigilance performed at the same time of day. Here we report that the SAT performance also alters circadian running wheel activity at ZT4 in a similar manner. Furthermore, the SAT performance causes phase advances (diurnality) at ZT4, a smaller phase advance at ZT10 and small phase delays at ZT16. Core body temperatures (Tb) are consistent with running wheel records for training at ZT10 and ZT16. However, at ZT4 the Tb is no longer synchronized with running wheel records, and contain elements of both daily training and LD effects. Acetylcholine (ACh) release in the prefrontal cortex, as measured via microdialysis, anticipates and remains entrained for at least 3 days after the last training session at ZT4. Entrainment to the time of daily training also occurs at ZT16, but the anticipatory rise is absent. In contrast, an operant schedule of reinforcement devoid of explicit demands on cognitive processes (FI-9) did not shift activity at ZT4 also did not entrain ACh release. Animals practicing at ZT4 the SAT, but not the FI-9, exhibit dampened food intake, stool output, and corticosterone rhythms in addition to the noted changes in activity rhythms and ACh release. Finally, the per2 rhythm in the colon also had a dampened level of expression. These data suggest that attention-demanding tasks may act to attenuate SCN-control of peripheral oscillators

REINAS: Real-Time Environmental Information Network and Analysis System: Phase IV.1-EXPERIMENTATION

The Real-Time Environmental Information Network and Analysis System (REINAS) is a continuing engineering research and development program with the goal of designing, developing and testing an operational prototype system for data acquisition, data management, and visualization. This system is to support the real-time utilization of advanced instrumentation in environmental science. Advances in continuous time measurements and improved spatial resolution allow the monitoring and understanding environmental phenomena in much greater detail than has previously been possible. The system is also designed to support the retrospective use of integrated environmental data sets. The project is a multi-year effort of the Baskin Center for Computer Engineering and Information Sciences of the University of California, Santa Cruz (UCSC), in cooperation with environmental scientists from the Naval Postgraduate School (NPS), and Monterey Bay Aquarium Research Institute (MBARI). The REINAS system has ..

Novette: a short wavelength laser-target interaction system

Novette has been designed to deliver 18.0 kJ in 1 nsec and 28 kJ in 3 nsec as maximum damage limited drive to the frequency conversion arrays. We expect maximum frequency doubled on-target energies of 13 kJ in 1 nsec and 20 kJ in 3 nsec. Propagation studies performed as Novette has been activated will be reviewed and their bearing on the Nova laser design discussed. The characteristics of the incident laser radiation in the target chamber center will be described