Sampled-grating DBR laser-based analog optical transmitters

Sampled-grating distributed Bragg grating (SGDBR) laser-based widely tunable optical transmitters are investigated for application in high-performance analog links. More than 45 nm tuning range, 40 dB sidemode suppression ratio, and peak relative intensity noise below -153 dB/Hz is measured. SGDBR lasers integrated with semiconductor optical amplifiers and electroabsorption modulators (EAMs) are characterized with spurious free dynamic range of 125-127 dB/spl middot/Hz/sup 4/5/ over the wavelength tuning range. It is also shown how the modulation response of the EAM is affected by the optical power to limit the performance of the analog transmitter.     

Biphasic insulin secretion during intravenous glucose tolerance test promotes optimal interstitial insulin profile

We examined the hindlimb lymph insulin profile during simulated intravenous glucose tolerance tests (IVGTTs) in anesthetized dogs to test the following hypotheses: 1) the biphasic insulin response to intravenous glucose can be seen as a priming bolus and a secondary infusion that effect a rapid stepwise increase in the interstitial insulin concentration and 2) the activation of glucose utilization (rate of glucose uptake [Rd]) during an IVGTT is more similar to the dynamics of the interstitial insulin profile than that of the arterial plasma. Three insulin profiles were infused: a normal biphasic pattern, a second phase infusion only, and a biphasic pattern with a fourfold greater first phase and a normal second phase. During the normal biphasic infusion, lymph insulin quickly reached and maintained a steady-state concentration (10 min, 26.42 +/- 0.86 microU/ml). With second phase only, it took lymph insulin 35 min to reach a steady state of lower concentration (13.13 +/- 0.46 microU/ml) than the normal. And with a fourfold greater first phase, lymph insulin plateaued quickly (16 min, 140.87 +/- 1.68 microU/ml), but for a shorter duration than the normal. For each profile, the time course of activation of Rd did not follow the time course of insulin in the plasma, but was more similar to that of insulin in the interstitial fluid. These results show that the biphasic response allows interstitial insulin to rapidly reach and maintain a steady state beneficial to activation and maintenance of glucose utilization.     

CW operation of 1.55-/spl mu/m bipolar cascade laser with record differential efficiency, low threshold, and 50-/spl Omega/ matching

By electrically segmenting an InP ridge laser and series-connecting the segments, we have created the first highly scalable bipolar cascade lasers. We report room-temperature continuous-wave operation of 12-stage lasers with a record 390% differential efficiency and 2.8-mA threshold, as well as three-stage lasers with 50-/spl Omega/ input impedance and 118% efficiency.     

The impact of acquired hearing impairment on intimate relationships: implications for rehabilitation

Hearing disabilities, due to their interactive nature, strongly affect intimate relationships. This paper reviews the literature on this dimension of the experience of hearing impairment. The effects of progressive hearing loss and of the coping process within the couple are examined borrowing concepts from symbolic interaction theory. A summary of the interactive dimensions of the effects of hearing impairment on the couple is drawn from the relevant studies. Specific needs have been identified for each partner in terms of information, support and communication facilitation. Implications are drawn for the audiological rehabilitation of hearing-impaired adults.     

Some consequences of the reaction to an aversive event.

In a free-responding situation an animal that merely reacts to an aversive event may appear to anticipate that event. To illustrate this problem, one of the typical reactions of a rat to a brief electric shock is considered. Although electric shock usually reduces the overall response rate, a given shock often leads to a burst of responses. The simulated behavior of such purely reactive Ss resembles the actual behavior of rats under conditions of nondiscriminative avoidance and punishment. Similar problems arise in other learning situations, and the yoked design is shown to be an inappropriate control, even without the assumption of individual differences. Several tests are described that distinguish the anticipation of an event from the reaction to an event. (17 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

High efficiency widely tunable SGDBR lasers for improved direct modulation performance

We report on two novel approaches to improve the differential quantum efficiency (DQE) of widely tunable 1.55-/spl mu/m lasers: the bipolar cascade sampled grating distributed Bragg reflector (BC-SGDBR) laser and the gain-levered SGDBR (GL-SGDBR) laser. Each is fabricated on a robust InGaAsP/InP photonic integrated circuit platform. The lasers demonstrate improved direct modulation performance over conventional SGDBR lasers. The BC-SGDBR laser was also monolithically integrated with a semiconductor optical amplifier and photodetector receiver in order to perform wavelength conversion. Error free wavelength conversion at 2.5 Gb/s and improvements in conversion efficiency are demonstrated.     

Design and evaluation issues in an experiment on teaching thinking skills.

Addresses methodological issues (related to design and analyses) raised by G. J. Mellenbergh and W. P. Van den Brink (see record 1988-37230-001) and I. S. Schonfeld (1987) concerning the study by the present author and colleagues (see record 1987-08654-001) on teaching thinking skills. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Control of Escherichia coli O157:H7 in Large (115 mm) and Intermediate (90 mm) Diameter Lebanon-style Bologna

Lebanon bologna raw batter was inoculated with Escherichia coli O157:H7 to achieve a level of 7.5 to 7.9 log cfu/g on MacConkey sorbitol agar, 202 agar, and phenol red agar with 1% sorbitol. Batter was stuffed into 115- or 90-mm dia casings and processed individually in a commercial smokehouse. For both diameter products, a 5-log reduction occurred, regardless of come-up times to reach specific internal temperatures (I.T.) or media used when the fermentation process consisted of 8 h at an I.T. of 26.7 °C, then 24 h at 37.8 °C I.T., followed by 24 h at 43.3 °C I.T.