Spatial optical solitons supported by mutual focusing

We study composite spatial optical solitons supported by two-wave mutual focusing induced by cross-phase modulation in Kerr-like nonlinear media. We find the families of both single- and two-hump solitons and discuss their properties and stability. We also reveal remarkable similarities between recently predicted holographic solitons in photorefractive media and parametric solitons in quadratic nonlinear crystals.Comment: 3 pages, 3 figure

Course profiling system

Course Profiling System (CPS) is a document management system for self-evaluation of first degree programmes at Private Higher Education Institutions (PHEIs). The framework provides systematic compliancy-checking of curriculum design with the Malaysian Qualifications Agency (MQA)Minimal Standards; and a more holistic view of the programme and its constituent courses.The novelty is the system’s design that reduces efforts and errors inherent in manual process.Apart of serving as a repository and retrieval of course profiles, CPS is also a platform for managing and monitoring the quality of PHEI’s programme for application and upkeep of MQA accreditation or renewa

Cooperative bathymetry-based localization using low-cost autonomous underwater vehicles

We present a cooperative bathymetry-based localization approach for a team of low-cost autonomous underwater vehicles (AUVs), each equipped only with a single-beam altimeter, a depth sensor and an acoustic modem. The localization of the individual AUV is achieved via fully decentralized particle filtering, with the local filter’s measurement model driven by the AUV’s altimeter measurements and ranging information obtained through inter-vehicle communication. We perform empirical analysis on the factors that affect the filter performance. Simulation studies using randomly generated trajectories as well as trajectories executed by the AUVs during field experiments successfully demonstrate the feasibility of the technique. The proposed cooperative localization technique has the potential to prolong AUV mission time, and thus open the door for long-term autonomy underwater.Massachusetts Institute of Technology. Department of Mechanical EngineeringSingapore-MIT Alliance for Research and Technology (SMART) (Graduate Fellowship

Adaptive Autocentering Control for an .Active Magnetic Bearing Supporting a Rotor with Unknown Mass Imbalance

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/57790/1/LumAutocenteringTCST1996.pd

Are there any known health risks to early introduction of solids to an infant's diet?

Few studies support an association between early introduction of solid food and atopic conditions, obesity, or any other illness (strength of recommendation [SOR]: B, cohort studies with mixed results). Very weak evidence suggests an increased risk of atopic dermatitis. A single cohort study found an association between early gluten exposure and increased risk of celiac disease in high-risk infants, who carry the HLA-DR3 or DR4 allele (SOR: B, single cohort study)

Parallel super-resolution imaging

Massive parallelization of scanning-based super-resolution imaging allows fast imaging of large fields of view

Near-bottom flow characteristics of currents at arbitrary angle to 2D ripples

Experimental results for near-bottom current velocity profiles for flows over artificial, definitely 2D ripples made of 1.5 cm high aluminum angle -profile spaced at 10 cm intervals are obtained for the following cases: (i)current alone perpendicular to ripples; (ii) current alone parallel to ripples; (iii) combined orthogonal wave-current flows for current parallel to ripples; and (iv) current alone at an angle of 30° to the ripple axis. The velocity profiles are analyzed by the log-profile method, and show the roughness experienced by the current to increase as the angle between ripple and current direction increases, i.e. demonstrating convincingly the reality of the concept of a direction-dependent roughness for flows over a 2D rippled bottom. Roughness experienced by the velocity component perpendicular to the ripples is, however, found to be independent of the direction of the mainstream flow relative to that of the ripples, and the different roughness experienced by the perpendicular and parallel velocity components gives rise to a turning of the current velocity vector to become increasingly aligned with the ripple crests as the bottom is approached from above. Implications of this feature, in terms of net sediment transport direction in combined wave-current flows in inner-shelf coastal waters, is discussed.Singapore–MIT Alliance for Research and Technology ((SMART) Center for Environmental Sensing and Modeling)Singapore. National Research Foundatio

Wide-field two-photon microscopy with temporal focusing and HiLo background rejection

Scanningless depth-resolved microscopy is achieved through spatial-temporal focusing and has been demonstrated previously. The advantage of this method is that a large area may be imaged without scanning resulting in higher throughput of the imaging system. Because it is a widefield technique, the optical sectioning effect is considerably poorer than with conventional spatial focusing two-photon microscopy. Here we propose wide-field two-photon microscopy based on spatio-temporal focusing and employing background rejection based on the HiLo microscope principle. We demonstrate the effects of applying HiLo microscopy to widefield temporally focused two-photon microscopy

Detailed Mapping of the Local Ir⁴⁺ Dimers through the Metal-Insulator Transitions of CuIr₂S₄ Thiospinel by X-ray Atomic Pair Distribution Function Measurements

The evolution of the short-range structural signature of the Ir 4+ dimer state in CuIr2S4 thiospinel has been studied across the metal-insulator phase transitions as the metallic state is induced by temperature, Cr doping, and x-ray fluence. An atomic pair distribution function (PDF) approach reveals that there are no local dimers that survive into the metallic phase when this is invoked by temperature and doping. The PDF shows Ir4+ dimers when they exist, regardless of whether or not they are long-range ordered. At 100 K, exposure to a 98 keV x-ray beam melts the long-range dimer order within a few seconds, though the local dimers remain intact. This shows that the metallic state accessed on warming and doping is qualitatively different from the state obtained under x-ray irradiation

Survivability of Vibrio parahaemolyticus in satar and otak-otak, Malaysian fish-based street food

Street food is popular in Asia due to its availability, low price and good taste. The safety of street food has been always questionable due to its poor handling which probably leads to microbial contamination. The objective of this study was to determine the surviving quantities of V. parahaemolyticus under various conditions in street-vended food, namely satar and otak-otak after anticipated cross-contamination to support policy and regulatory documents. The satar and otak-otak were prepared from minced and unminced fish flesh, respectively, together with other ingredients. Each satar and otak-otak were prepared with 0, 0.5, 1.5 and 3% of sodium chloride (NaCl), respectively. V. parahaemolyticus inoculum at approximately 8.66 log CFU/ml were inoculated into the samples and incubated for up to 6 h. Samples were taken at 0, 1, 3 and 6 h for enumeration of V. parahaemolyticus using spread plate method on Thiosulphate Citrate Bile Salts Sucrose (TCBS) agar. For control samples, V. parahaemolyticus was not immediately inactivated in distilled water even though significant better survivability was observed in Phosphate Buffer Saline (PBS). The numbers of V. parahaemolyticus was found to decrease by varying amounts based on the salt content and duration of holding. However, significant amounts survived to indicate potential risk