The present study on politeness is an attempt to examine (dis)agreeing strategies utilized by EFL learners while chatting on the internet. Subjects of the study were forty male and thirty-three female Iranian natives whose internet relay chat (IRC) interactions, composed of 400 excerpts, were collected between December 2007 and September 2008. Data analysis was based on the general taxonomy of politeness strategies suggested by Brown and Levinson (1987) which is the baseline of many politeness studies today. The results indicate that IRC is a mode of communication whose characteristics are typically different from face-to-face and real-life conversational settings. Some common face threatening acts (FTAs) like ‘direct disagreements’ are performed widely in chat channels. Furthermore, gender-oriented differences were found not to be statistically significant on the internet.

Background: Previous literatures have shown a transient ischemic attack (TIA) mimic rate of 9-31%. We aimed to ascertain the proportion of stroke mimics amongst suspected TIA patients.Methods: A prospective observational study was performed in Ghaem Hospital, Mashhad, Iran during 2012-2013. Consecutive TIA patients were identified in a stroke center.The initial diagnosis of TIA was made by the resident of neurology and final diagnosis of true TIA versus TIA mimics was made after 3 months follow-up by stroke subspecialist.Results: A total of 310 patients were assessed during a 3-month period of which 182 (58.7%) subjects were male and 128 (41.3%) were female. Ten percent of the patients was categorized as a TIA mimic. The presence of hypertension, aphasia, duration of symptoms, and increased age was the strongest predictor of a true TIA. Migraine was the most common etiology of stroke mimic in our study.Conclusion: It seems that many signs and symptoms have low diagnostic usefulness for discrimination of true TIA from non-cerebrovascular events and predictive usefulness of any sign or symptom should be interpreted by a stroke neurologist.

Cooperative Spectrum Sensing (CSS) is an effective approach to overcome the impact of multi-path fading and shadowing issues. The reliability of CSS can be severely degraded under Byzantine attack, which may be caused by either malfunctioning sensing terminals or malicious nodes. Almost, the previous studies have not analyzed and considered the attack in their models. The present study introduces a new issue named attack-aware CSS where the objective is to analyze the occurred attack against CR network to ameliorate the performance of data fusion schemes. The novelty includes the modification of Weighted Sequential Probability Ratio Test (WSPRT) algorithm which resulted in Attack-Aware WSPRT (A2WSPRT). The findings indicated considerable reduction in cooperation overhead and enhancement in correct sensing ratio, especially in severe attacks.