University of Arkansas

About: University of Arkansas is a education organization based out in Fayetteville, Arkansas, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 17225 authors who have published 33329 publications receiving 941102 citations. The organization is also known as: Arkansas & UA.

Salmonellosis Outbreaks in the United States Due to Fresh Produce: Sources and Potential Intervention Measures

Abstract: Foodborne Salmonella spp. is a leading cause of foodborne illness in the United States each year. Traditionally, most cases of salmonellosis were thought to originate from meat and poultry products. However, an increasing number of salmonellosis outbreaks are occurring as a result of contaminated produce. Several produce items specifically have been identified in outbreaks, and the ability of Salmonella to attach or internalize into vegetables and fruits may be factors that make these produce items more likely to be sources of Salmonella. In addition, environmental factors including contaminated water sources used to irrigate and wash produce crops have been implicated in a large number of outbreaks. Salmonella is carried by both domesticated and wild animals and can contaminate freshwater by direct or indirect contact. In some cases, direct contact of produce or seeds with contaminated manure or animal wastes can lead to contaminated crops. This review examines outbreaks of Salmonella due to con...

Object-based change detection using correlation image analysis and image segmentation

Abstract: This study introduces change detection based on object/neighbourhood correlation image analysis and image segmentation techniques. The correlation image analysis is based on the fact that pairs of brightness values from the same geographic area (e.g. an object) between bi-temporal image datasets tend to be highly correlated when little change occurres, and uncorrelated when change occurs. Five different change detection methods were investigated to determine how new contextual features could improve change classification results, and if an object-based approach could improve change classification when compared with per-pixel analysis. The five methods examined include (1) object-based change classification incorporating object correlation images (OCIs), (2) object-based change classification incorporating neighbourhood correlation images (NCIs), (3) object-based change classification without contextual features, (4) per-pixel change classification incorporating NCIs, and (5) traditional per-pixel change classification using only bi-temporal image data. Two different classification algorithms (i.e. a machine-learning decision tree and nearest-neighbour) were also investigated. Comparison between the OCI and the NCI variables was evaluated. Object-based change classifications incorporating the OCIs or the NCIs produced more accurate change detection classes (Kappa approximated 90%) than other change detection results (Kappa ranged from 80 to 85%).

Programme for International Student Assessment (PISA)

Abstract: Since the assessment program began in 1997, over 70 countries have participated at least once. Every three years, a randomly selected group of 15-year-old students take the test, which primarily focuses on one key subject.

Endogenous salicylic acid protects rice plants from oxidative damage caused by aging as well as biotic and abiotic stress

Abstract: Salicylic acid (SA) is a key endogenous signal that mediates defense gene expression and disease resistance in many dicotyledonous species. In contrast to tobacco and Arabidopsis, which contain low basal levels of SA, rice has two orders of magnitude higher levels of SA and appears to be insensitive to exogenous SA treatment. To determine the role of SA in rice plants, we have generated SA-deficient transgenic rice by expressing the bacterial salicylate hydroxylase that degrades SA. Depletion of high levels of endogenous SA in transgenic rice does not measurably affect defense gene expression, but reduces the plant's capacity to detoxify reactive oxygen intermediates (ROI). SA-deficient transgenic rice contains elevated levels of superoxide and H2O2, and exhibits spontaneous lesion formation in an age- and light-dependent manner. Exogenous application of SA analog benzothiadiazole complements SA deficiency and suppresses ROI levels and lesion formation. Although an increase of conjugated catechol was detected in SA-deficient rice, catechol does not appear to significantly affect ROI levels based on the endogenous catechol data and exogenous catechol treatment. When infected with the blast fungus (Magnaporthe grisea), SA-deficient rice exhibits increased susceptibility to oxidative bursts elicited by avirulent isolates. Furthermore, SA-deficient rice is hyperresponsive to oxidative damage caused by paraquat treatment. Taken together, our results strongly suggest that SA plays an important role to modulate redox balance and protect rice plants from oxidative stress.