Motion of magnetotactic bacteria swarms in an external field

Magnetotactic bacteria moving on circular orbits form hydrodynamically bound states. When close to a surface and with the tilting of the field in a direction close to the perpendicular to this surface these swarms move perpendicularly to the tilting angle. We describe quantitatively this motion by a continuum model with couple stress arising from the torques produced by the rotary motors of the amphitrichous magnetotactic bacteria. The model not only correctly describes the change of direction of swarm motion while inverting the tangential field but also predicts reasonable value of the torque produced by the rotary motors

Integrated dual-wavelength AWG laser for sub-terahertz wave generation

We present a monolithically integrated ring dual-wavelength semiconductor laser in which both wavelengths (¿1 and ¿2) are generated and amplified by the same semiconductor optical amplifier (SOA). An arrayed waveguide grating (AWG) is used as intra-cavity filter to combine the two wavelengths. The use of a Mach-Zehnder construction allows equalizing actively the power of ¿1 and ¿2 and tuning their frequencies. An analytical model is exploited to investigate the influence of crosstalk on the functioning of the device and to identify a calibration strategy. The device has been fabricated using active/passive integration technology on a standardized photonic integration platform

Traveling wave model of an AWG-based multiwavelength laser

This work presents a traveling wave model description of an arrayed waveguide grating (AWG) based multiwavelength laser. The purpose is to design a device with frequency spacing of 70 GHz between channels at 1550 nm central wavelength, aiming to dimension the required channel bandwidth to achieve a target side mode suppression ratio (SMSR) among longitudinal modes

Individual Neurons Confined to Distinct Antennal-Lobe Tracts in the Heliothine Moth: Morphological Characteristics and Global Projection Patterns

To explore fundamental principles characterizing chemosensory information processing, we have identified antennal-lobe projection neurons in the heliothine moth, including several neuron types not previously described. Generally, odor information is conveyed from the primary olfactory center of the moth brain, the antennal lobe, to higher brain centers via projection neuron axons passing along several parallel pathways, of which the medial, mediolateral, and lateral antennal-lobe tract are considered the classical ones. Recent data have revealed the projections of the individual tracts more in detail demonstrating three main target regions in the protocerebrum; the calyces are innervated mainly by the medial tract, the superior intermediate protocerebrum by the lateral tract exclusively, and the lateral horn by all tracts. In the present study, we have identified, via iontophoretic intracellular staining combined with confocal microscopy, individual projection neurons confined to the tracts mentioned above, plus two additional ones. Further, using the visualization software AMIRA, we reconstructed the stained neurons and registered the models into a standard brain atlas, which allowed us to compare the termination areas of individual projection neurons both across and within distinct tracts. The data demonstrate a morphological diversity of the projection neurons within distinct tracts. Comparison of the output areas of the neurons confined to the three main tracts in the lateral horn showed overlapping terminal regions for the medial and mediolateral tracts; the lateral tract neurons, on the contrary, targeted mostly other output areas in the protocerebrum

III-V-on-silicon anti-colliding pulse-type mode-locked laser

An anti-colliding pulse-type III–V-on-silicon passively mode-locked laser is presented for the first time based on a III–V-on-silicon distributed Bragg reflector as outcoupling mirror implemented partially underneath the III–V saturable absorber. Passive mode-locking at 4.83 GHz repetition rate generating 3 ps pulses is demonstrated. The generated fundamental RF tone shows a 1.7 kHz 3 dB linewidth. Over 9 mW waveguide coupled output power is demonstrated

Characterisation of monolithically integrated dual wavelength AWG-lasers for mm-wave generation

In this paper we present characterisation results of monolithically integrated InP based quantum well dual wavelength lasers in which an Array Waveguide Grating (AWG) is used as intra-cavity filter to allow lasing on two wavelengths within a common optical amplifier of the device. The devices require accurate control of the optical loss of each wavelength which is achieved through the use of Michelson interferometers (MIs) in the cavity. The results show that reasonably stable dual wavelength operation is possible with a side mode suppression ratio better than 20dB for each of the two wavelengths without fast active feedback control

Integrated dual wavelength lasers for millimeter wave generation

We have designed integrated dual-wavelength lasers in which an array waveguide grating is used as intra-cavity filter to allow lasing on two wavelengths within a common arm of the device. The devices have been designed with the purpose to exploit the beating of the two wavelengths on a photodiode in order to generate a 70GHz carrier wave. The use of a common SOA to amplify both wavelengths is promising for reducing the variations in frequency difference between the two operating laser modes. Both linear and ring configuration have been explored

Status Management: A Theory of Punishment and Rehabilitation

This report outlines the Status Management Theory, originally titled the Degradation-Accreditation Theory for application in correctional settings for deterrence or rehabilitation of criminal perpetrators