The effect of methionine starvation on the motility and behavior of normal and nonchemotactic mutants of Salmonella typhimurium was investigated. Methionine starvation eliminates tumbling in the wild type, but fails to do so in an uncoordinated (frequent tumbling) mutant. In the mutant, methionine starvation significantly extends the period of smooth motility that follows a sharp temporal incre...

Chemotaxis is ubiquitously performed by bacteria. They sense and move toward a region with a higher concentration of an attractive chemical by changing the rate of tumbling for random walk. We numerically studied several models with internal adaptive dynamics to examine the validity of the condition for chemotaxis proposed by Oosawa and Nakaoka [J. Theor. Biol. 66, 747 (1977)], which states tha...

To date, workflow management focuses on improving the effectivity and efficiency of business processes within one organization. However, today’s corporations are challenged to cross organizational boundaries. Phenomena such as electronic commerce, extended enterprises and the Internet stimulate the cooperation between organizations. Therefore, it is interesting to consider workflows distributed...

The two-dimensional Smoluchowski equation is employed to study the effect of elongational perturbations on nematic liquid crystal polymers under a weak shear. We use the multiscale asymptotic analysis to show that 1 when the elongational perturbation is small relative to the weak shear, the orientational probability density function pdf tumbles periodically only in an intermediate range of poly...

preparing thermal comfort conditions in outdoor public spaces is one of the considerations of architectural design. if the constructed area does not support comfortable conditions in outdoor spaces, it will cause microclimatic problems for pedestrians and adjacent buildings. regarding the different thermal comfort conditions in outdoor spaces in comparison with indoor, several indices have been...

BACKGROUND The aim of this cross-sectional study is to ascertain the prevalence and causes of blindness, visual impairment, uptake of cataract surgery among different ethnic groups in Xinjiang Uygur Autonomous Region, China. METHODS Four thousand one hundred fifty people at 50 years and above from different minority ethnic groups were randomly selected for an eye examination. The four trained...

PURPOSE To determine the prevalence of blindness and visual impairment among adults aged > or = 40 years in Nigeria. METHODS Multistage, stratified, cluster random sampling with probability proportional to size procedures was used to identify a cross-sectional nationally representative sample of 15,027 persons > or = 40 years of age from all 36 states in Nigeria and the Federal Capital Territ...

PURPOSE To provide data on prevalence and types of refractive error and the spectacle-wearing rate among adults in Nigeria and the degree to which the need for distance correction could be met by off-the-shelf spectacles. METHODS Multistage, stratified, cluster random sampling with probability proportional to size was used to identify a nationally representative sample of 15,027 persons aged ...

In the past, case study and questionnaire survey methodologies have often been used to analyze causes of marine accidents. One disadvantages these two methods is that they can only interpret specific one particular accident at a time. They cannot find common most Therefore, this integrates Automatic Identification System, Geographic Information an e-chart explore relationship between environmen...