Distribution and abundance of high aquatic plants in the Gorganroud River, the Caspian Sea basin, Iran

The distribution and abundance of high aquatic plants in the Gorganroud River was examined at five stations in four seasons (20 samples) over one year period during 2009-2010. We identified 21 species of aquatic plants from 21 genera, belonging to 9 families. These species were determined as 3 halophytic species (14.2%) and 18 high aquatic plants (85.7%).The highest species diversity was observed at Khajenafas, Aq qala and Chargoli stations(17, 13 and 11 species) respectively, The highest biomass of high aquatic plants were recorded in summer (for Inspection and Chargoli stations 11.5 and 10.1 g.m-2, respectively) and autumn (for the station of Inspection was 8.5 g.m-2 dry weight). The most dominant species were different in the investigated stations. At station 1 species Tamarix kotschyi, at station 2 species Juncus acutiflorus, at station 3 species Hordeum murinum hudson, at station 4 species Salicornia europaea L and at station 5 Juncus acutiflorus species were dominated

A New Protocol for Cooperative Spectrum Sharing in Mobile Cognitive Radio Networks

To optimize the usage of limited spectrum resources, cognitive radio (CR) can be used as a viable solution. The main contribution of this article is to propose a new protocol to increase throughput of mobile cooperative CR networks (CRNs). The key challenge in a CRN is how the nodes cooperate to access the channel in order to maximize the CRN's throughput. To minimize unnecessary blocking of CR transmission, we propose a so-called new frequency-range MAC protocol (NFRMAC). The proposed method is in fact a novel channel assignment mechanism that exploits the dependence between signal's attenuation model, signal's frequency, communication range, and interference level. Compared .to the conventional methods, the proposed algorithm considers a more realistic model for the mobility pattern of CR nodes and also adaptively selects the maximal transmission range of each node over which reliable transmission is possible. Simulation results indicate that using NFRMAC leads to an increase of the total CRN's throughput by 6% and reduces the blocking rate by 10% compared to those of conventional methods

The effect of gag reflex on cardiac sympatovagal tone

Objectives: Heart velocity may be influenced by gagging. The medulla oblongata receives the afferents of gag reflex. Neuronal pools of vomiting, salivation and cardiac parasympathetic fibers are very close in this area. So, their activities may be changed by spillover from each other. Using the heart rate variability (HRV) analysis, the effect of gagging on cardiac sympatovagal balance was studied. Methods: ECG was recorded from 9 healthy nonsmoker volunteer students for 10 minutes in the sitting position between 10 and 11 AM. Gagging was elicited by tactile stimulation of the posterior pharyngeal wall. At 1 kHz sampling rate, HRV was calculated. The mean of heart rate at low and high frequencies (LF: 0.04-0.15; HF: 0.15-0.4 Hz) were compared before and after the stimulus. Results: The mean of average heart rate, LF and HF in normalized units (nu) and the ratio of them (LF/HF) before and after the gagging were 89.9 ± 3 and 95.2 ± 3 bpm; 44.2 ± 5.8 and 21.2 ± 4; 31.1 ± 5.3 and 39.4 ± 3.8; and 1.7 ± 0.3 and 0.6 ± 0.2 respectively. Conclusion: Gagging increased heart velocity and had differential effect on two branches of cardiac autonomic nerves. The paradoxical relation between average heart rate and HRV indexes of sympatovagal tone may be due to unequal rate of change in autonomic fiber activities which is masked by 5 minutes interval averaging. © OMSB, 2012

Educational Ethics in Academic Environment: Medical Students' Perspectives

Background and Objective: Educational ethics imply values such as honesty, reliance on one's own personal effort, not to abuse the efforts of others, and respect the dignity and respect for others. Students are faced with different situations in which they show various moral and immoral behaviors. This study aimed to explore medical students' viewpoints and experiences at Golestan University of Medical Sciences about ethics in academic environment in 2013. Materials and Methods: In this qualitative study a purposive sampling was used with maximum variation and 12 medical students participated in the research. Data was gathered using semi-structured interviews. At least an open question "When I say ethics in education or educational environment, what comes to your mind" was repeated in all the interviews. The interviews recorded and transcribed line by line and then analyzed according to "conventional content analysis" method. Results: "Respecting teacher dignity", "preserving dignity of classroom", "respecting and maintaining dignity for classmates", "seeking for knowledge and sciences” emerged as the main themes of the current study. Conclusion: University students considered learning environment as a sacred place; conforming its expected rules and ethics would be mandatory. Abnormal behavior causes not only loss of students dignity but also could be harmful to the calmness of educational atmosphere and may evoke different unpleasant pessimistic ideas about such academic environment