Digestive Manifestations in Patients Hospitalized With Coronavirus Disease 2019.

Background & Aims: The prevalence and significance of digestive manifestations in coronavirus disease 2019 (COVID-19) remain uncertain. We aimed to assess the prevalence, spectrum, severity, and significance of digestive manifestations in patients hospitalized with COVID-19.

Methods: Consecutive patients hospitalized with COVID-19 were identified across a geographically diverse alliance of medical centers in North America.

Wavelength-versatile subpicosecond pulsed lasers using Raman gain in figure-of-eight fiber geometries.

A family of compact pulsed fiber lasers is described that employs broadband, wavelength-flexible Raman scattering in passively mode-locked figure-of-eight fiber laser geometries. Specifically, sources at 1.57, 1.

Red picosecond pulses generated by frequency doubling a Raman amplified widely tunable 1.3 microm fiber ring laser.

We generated 0.66 microm picosecond pulses by second-harmonic generation of the Raman amplified output of a 1.3 microm actively mode-locked fiber ring laser in a periodically poled potassium titanyl phosphate (PPKTP) waveguide.

Compact, synchronously diode-pumped tunable fiber Raman source of subpicosecond solitons around 1.6 microm.

A compact and simple all-fiber subpicosecond soliton source is demonstrated that employs synchronous Raman amplification in dispersion-shifted fiber from a gain-switched 1536-nm laser diode pump. Tuning between 1620 and 1660 nm is obtained by electronic variation of the gain-switching frequency around 54.47 MHz, and solitons as short as 400 fs are achieved.

Soliton self-frequency shift in highly nonlinear fiber with extension by external Raman pumping.

A completely fiber-integrated, wavelength-tunable subpicosecond pulse source is demonstrated using the soliton self-frequency shift in highly nonlinear dispersion-shifted fiber from a 1.56-microm 10-GHz 400-fs signal. Solitons as short as 100 fs are obtained at tunable wavelengths as high as 1.

Gain-flattened fiber Raman amplifiers with nonlinearity-broadened pumps.

Gain flattening of an E-band (1360-1460-nm) fiber Raman amplifier was achieved by pump spectral broadening to a 16.3-nm linewidth by use of nonlinearity in a 6.2-km standard fiber.

Impulsivity resulting from frontostriatal dysfunction in drug abuse: implications for the control of behavior by reward-related stimuli.

Drug abuse and dependence define behavioral states involving increased allocation of behavior towards drug seeking and taking at the expense of more appropriate behavioral patterns. As such, addiction can be viewed as increased control of behavior by the desired drug (due to its unconditioned, rewarding properties). It is also clear that drug-associated (conditioned) stimuli acquire heightened abilities to control behaviors.