Sleep drive is coupled to tissue damage via shedding of Caenorhabditis elegans EGFR ligand SISS-1.

The benefits of sleep extend beyond the nervous system. Peripheral tissues impact sleep regulation, and increased sleep is observed in response to damaging conditions, even those that selectively affect non-neuronal cells. However, the 'sleep need' signal released by stressed tissues is not known.

Multi-aperture digital coherent combining for free-space optical communication receivers.

Space-to-ground optical communication systems can benefit from reducing the size, weight, and power profiles of space terminals. One way of reducing the required power-aperture product on a space platform is to implement effective, but costly, single-aperture ground terminals with large collection areas. In contrast, we present a ground terminal receiver architecture in which many small less-expensive apertures are efficiently combined to create a large effective aperture while maintaining excellent receiver sensitivity.

Scalable modulator for frequency shift keying in free space optical communications.

Frequency shift keyed (FSK) modulation formats are well-suited to deep space links and other high loss links. FSK's advantage comes from its use of bandwidth expansion. I.

Photon-counting 1.55 microm optical communications with pulse-position modulation and a multimode upconversion single-photon receiver.

We report single-photon frequency upconversion of multimode light from 1.55 to 0.532microm and demonstrate an end-to-end optical link that emulates photon-starved communications and atmospheric propagation.

Efficient performance optimization of SOA-MZI devices.

We present a novel characterization method for semiconductor optical amplifier Mach-Zehnder interferometer (SOA-MZI) switches which combines a pump-probe measurement with an interferometer bias scan. In addition to a wealth of information on the switching dynamics for all operating points of the switch, we can create an extinction map to pinpoint regions of highest extinction for optimizing all-optical ultrafast switching. We experimentally verify the accuracy of this characterization method by performing a wavelength characterization at the optimal bias point and a nearby, non-optimal point.

Wavelength-maintaining polarization-insensitive all-optical 3R regenerator.

High-rate long-haul fiber communications systems will require high-speed efficient signal regeneration. By introducing a simple semiconductor-optical-amplifier wavelength converter into the folded ultrafast nonlinear interferometer, we demonstrate a polarization-insensitive wavelength-maintaining 3R all-optical regenerator. The extinction ratio between the on and off states is 21 dB.

781 Mbit/s photon-counting optical communications using a superconducting nanowire detector.

We demonstrate 1550 nm photon-counting optical communications with a NbN-nanowire superconducting single-photon detector. Source data are encoded with a rate-1/2 forward-error correcting code and transmitted by use of 32-ary pulse-position modulation at 5 and 10 GHz slot rates. Error-free performance is obtained with -0.

All-optical pulse regeneration in an ultrafast nonlinear interferometer with Faraday mirror polarization stabilization.

We demonstrate the folded ultrafast nonlinear interferometer (FUNI) as a 3R all-optical regenerator. Faraday rotation provides inherent polarization stabilization, and the optical fiber nonlinear medium provides ultrafast operation and switching window tunability. We demonstrate 3R regeneration of 10-Gbit/s data with 5-pJ pulse switching energy and 4-ps timing-jitter tolerance.

Teenage pregnancy from the father's perspective.

Teenage pregnancy is examined from the perspective of a number of studies conducted with teenage fathers. Five commonly held myths about teenage fathers are contradicted by the research. Data on sexual knowledge and behavior, attitudes toward marriage and child rearing, psychological variables, and consequences of fatherhood are presented and implications for mental health practitioners are discussed.