| 21. |
- Abbas, Q., et al.
(author)
-
A Markovian Model for the Analysis of Age of Information in IoT Networks
- 2021
-
In: IEEE Wireless Communications Letters. - : Institute of Electrical and Electronics Engineers Inc.. - 2162-2337 .- 2162-2345. ; 10:7, s. 1596-1600
-
Journal article (peer-reviewed)abstract
- Age of Information (AoI) is a critical metric in status update systems as these systems require the fresh updates. This letter investigates the uplink of an Internet-of-Thing (IoT) network where L nodes transmit their information packets to a base station. The effects of the arrival rate of packets at the nodes, the number of nodes in the system, and queue length of each node have been studied by devising a discrete time Markov chain (MC) model. This model helps in predicting the values of AoI and probability of packet drops in such systems. The notion of first-in first-out is used for queuing, which transmits the oldest packet first, resulting in decreasing the overall AoI of the system. The results show that AoI increases with the increase in queue length, number of nodes and arrival rate and we quantify the aforementioned metrics using the MC model. The results found using the MC model are also validated using extensive simulations. © 2012 IEEE.
|
|
| 22. |
- Abbas, Q., et al.
(author)
-
Age of Information in Backscatter Communication
- 2021
-
In: Internet Things. - Cham : Springer. ; , s. 67-80
-
Conference paper (peer-reviewed)abstract
- Age of Information (AoI) has been introduced to characterize the newness of data which is observed in real time. In other words, it is the measure of time elapsed since the generation of last received update about a process and is a vital metric in networks such as Internet of things (IoTs), especially when the application demands fresh updates. Most of the applications require fresh data e.g., applications related to environmental monitoring, smart agriculture, body area networks etc. On the other hand backscatter communication promises to resolve one of the most challenging issues of IoT devices, i.e., making them capable for communication without the batteries. The importance of AoI in backscatter communication is paramount to gauge performance of backscatter IoT networks. This chapter addresses the significance of AoI in backscatter communication and suggests some techniques to design a communication system with minimum AoI, maximum energy efficiency, and minimum outage. © 2021, Springer Nature Switzerland AG.
|
|
| 23. |
- Abbasi, M., et al.
(author)
-
Fabrication of Spin-Coated Ti/TiHx/Ni-Sb-SnO2 Electrode : Stability and Electrocatalytic Activity
- 2018
-
In: Journal of the Electrochemical Society. - : ELECTROCHEMICAL SOC INC. - 0013-4651 .- 1945-7111. ; 165:9, s. H568-H574
-
Journal article (peer-reviewed)abstract
- A novel three-layer anode having the composition Ti/TiHx/Ni-Sb-SnO2 (Ti/TiHx/NATO) was successfully prepared by a spin-coating and pyrolysis process aiming at a long service lifetime and good electrocatalytic properties for ozone formation. The TiHx as an interlayer was produced by electrochemical cathodic reduction of a coated layer of the TiOx on the titanium substrate. Spin coating and thermal decomposition were used to deposit the Sn-Sb-Ni precursor on the surface of the prepared Ti/TiHx electrode. Cyclic and linear scanning voltammetry, Raman spectroscopy, scanning electron microscopy (SEM) and X-ray diffraction (XRD) were used to reveal the electrode performance and morphology. Results show that the onset potential for the oxygen evolution reaction (OER) of Ti/TiHx /NATO is higher than for Ti/NATO. They also indicate that the service lifetime of the Ti/TiHx/NATO is twice as long as the Ti/NATO at a current density of 50 mA.cm(-2) at room temperature. Electrochemical ozone generation and degradation of the methylene blue were investigated to confirm selectivity and activity of the electrodes. After 5 min electrolysis, a current efficiency for ozone generation of 56% was obtained the electrode with TiHx while 38% was obtained on Ti/NATO under same conditions. The results also confirm that the Ti/TiH x /NATO has a higher kinetic rate constant and decolorization efficiency for removal of the methylene blue compare to the Ti/NATO. The rate constant for the pseudo-first ordered reaction of methylene blue degradation showed high values of 350 x 10(-3) min(-1) for Ti/NATO and 440 x 10(-3) min(-1) for Ti/TiHx/NATO.
|
|
| 24. |
- Abbasi, Seyed
(author)
-
Determinants of social inequalities in cardiovascular disease among Iranian patients
- 2018
-
Doctoral thesis (other academic/artistic)abstract
- Background and objectives: Cardiovascular disease (CVD) is the single largest cause of mortality in the world. Similar to other health issues, CVD is generally affected either by individual risk factors, which may influence the risk for developing an illness or its complications, or by social indicators (social determinants of health). There is evidence from developed countries which shows that the so-called "upstream factors"—including social determinants such as political, social, spiritual, cultural, and economic factors—may affect the prevalence and incidence of CVD. Scarce evidence from studies in low- and middle-income countries also suggests that social factors may affect the distribution of CVD across population groups. However, there is a dearth of such data in Iran, where only a few small-sizedstudies have focused on the social determinants of health. Therefore, the present thesis sought to fill this gap by assessing the effects of socioeconomic status (SES) on the distribution of CVD and the relevant inequalities within the Iranian context.Methods: This thesis is based on four studies, which used data from the Tehran Heart Center’s Databases. In Study I, a total of 44,820 patients who underwent coronary angiography at Tehran Heart Center between 2005 and 2010 were recruited. Then, their pre- and post-procedural data—including demographics, CVD risk factors, symptoms, and laboratory tests—were compared between men and women. In Study II, 6,246 patients with acutecoronary syndrome who were hospitalized between March 2004 and August 2011 were included and, based on their education and their employment status, were divided into high- and low-SES groups. Thereafter, the effect of SES on the in-hospital death of the patients was evaluated. In Study III, 20,165 patients with documented coronary artery disease who underwent coronary angiography at Tehran Heart Center were enrolled and CVD risk factors and severity (measured by the Gensini score) were assessed among the six major Iranian ethnic groups. In Study IV, 9,088 patients with acute coronary syndrome who were hospitalized at Tehran Heart Center between May 2007and June 2014 were recruited and the association between in-hospital death due to acute coronary syndrome and place of residence (rural/urban) was assessed using logistic regression adjusted for potential confounders.Results: In this thesis, the data analyses were based on the hypothesis that there is a potential association between the different socioeconomic indicators and the selected cardiovascular outcomes. In Study I, among the recruited participant, 25,363 men and 11,995 women had coronary artery disease and the women not only were significantly older, less educated, and more overweight but also had higher blood levels of triglyceride, cholesterol, low-density lipoprotein, high-density lipoprotein, and fasting blood sugar than the men. Moreover, hypertension and diabetes mellitus showed the strongest association in the women with coronary artery disease (OR=3.45, 95% CI: 3.28to 3.61 and OR=2.37, 95% CI: 2.26 to 2.48, respectively). In addition, the frequency of post-procedural recommendations for non-invasive procedures was higher in the women than in the men (20.1% vs 18.6%; P<0.001). In StudyII, of the 6,246 recruited patients with acute coronary syndrome, 3,290individuals were considered low-SES and 2,956 high-SES individuals. In-hospital death occurred in 79 (1.26%) patients: 1.9% in the low-SES and 0.6% in the high-SES groups. After adjustment for the possible cofounders, our multivariate analysis demonstrated a significant effect of the patients’ SES on their in-hospital death and a lower in-hospital mortality rate was shown in the high-SES patients (OR=0.30, 95% CI: 0.09 to 0.98; P=0.046). In Study III, the Fars (8.7%) and Gilak (8.6%) ethnic groups had the highest frequency of having at least four simultaneous risk factors. Additionally, the mean Gensini score was lowest in the Lurs (67.5±52.8) and highest among the Gilaks (77.1±55.9). The multivariable regression analysis indicated that the Gilaks showed the worst CVD severity (β: 0.056, 95% CI: 0.009 to 0.102; P=0.018), followed by the Turks (β: 0.032, 95% CI: 0.005 to 0.059; P=0.020), and the lowest CVD severity, was detected in the Lurs (β: -0.087, 95% CI: -0.146 to -0.027;P=0.004). Study IV showed that while smoking (P=0.002), positive family history of coronary artery disease (P=0.003), higher body mass index (P=0.013),and hyperlipidemia (P=0.026) were more prevalent in the urban patients, the rural patients showed lower educational levels (P<0.001) and higher frequency of unemployment (P=0.009). Meanwhile, in-hospital death occurred in 135 (1.5%) patients: 125 (1.5%) urban and 10 (1.2%) rural. To adjust the effects of the possible confounders, we utilized the Firth regression model, which showed no significant difference regarding in-hospital death betweenthe rural and urban patients (OR=1.57, 95% CI: 0.376 to 7.450; P=0.585).Conclusions: The aim of this thesis was to investigate the effects of social determinants (particularly SES) on CVD and its modifiable risk factors among Iranian patients. Results showed that medical treatment for CVD was more recommended (by treating physicians) to the women than the men, and the low-SES patients with acute coronary syndrome were more likely to die in the hospital than their high-SES counterparts. In addition, the thesis found heterogeneity in the distribution of the traditional risk factors for CVD as well as CVD severity in the major Iranian ethnic groups. Further, there were no differences concerning the in-hospital death rates due to acute coronary syndrome between the urban and rural patients after adjustment for the potential confounders.
|
|
| 25. |
- Abbasi, Seyed H, et al.
(author)
-
Ethnic differences in the risk factors and severity of coronary artery disease : a patient-based study in Iran
- 2018
-
In: Journal of Racial and Ethnic Health Disparities. - : Springer Berlin/Heidelberg. - 2197-3792 .- 2196-8837. ; 5:3, s. 623-631
-
Journal article (peer-reviewed)abstract
- Background Diverse ethnic groups may differ regarding the risk factors and severity of coronary artery disease (CAD). This study sought to assess the association between ethnicity and CAD risk and severity in six major Iranian ethnic groups.Methods In this study, 20,165 documented coronary artery disease patients who underwent coronary angiography at a tertiary referral heart center were recruited. The demographic, laboratory, clinical, and risk factor data of all the patients were retrieved. The Gensini score (an indicator of CAD severity) was calculated for all, and the risk factors and severity of CAD were compared between the ethnical groups, using adjusted standardized residuals, Kruskal–Wallis test, and multivariable regression analysis.Results The mean age of the participants (14,131 [70.1%] men and 6034 [29.9%] women) was 60.7 ± 10.8 years. The Fars (8.7%) and Gilak (8.6%) ethnic groups had the highest prevalence of ≥4 simultaneous risk factors. The mean Gensini score was the highest for the Gilaks (77.1 ± 55.9) and the lowest among the Lors (67.5 ± 52.8). The multivariable regression analysis showed that the Gilaks had the worst severity (β 0.056, 95% CI 0.009 to 0.102; P = 0.018), followed by the Torks (β 0.032, 95% CI 0.005 to 0.059; P = 0.020). Meanwhile, the Lors showed the lowest severity (β −0.087, 95% CI −0.146 to −0.027; P = 0.004).Conclusions This study found that there was heterogeneity in CAD severity and a diverse distribution in its well-known traditional risk factors among major Iranian ethnic groups.
|
|
| 26. |
- Abbasi, Seyed H, et al.
(author)
-
Gender Differences in the Risk of Coronary Artery Disease in Iran
- 2012
-
In: Iranian Journal of Public Health. - 0304-4556. ; 41:3, s. 36-47
-
Journal article (peer-reviewed)abstract
- Background: Given gender differences in the risk of coronary artery disease (CAD), the present study sought to investigate these dissimilarities amongst patients who underwent angiography at a major, tertiary heart hospital in Iran. Methods: Between 2005 and 2010, 44,820 patients who underwent coronary angiography were enrolled in a registry. Pre-procedural data such as demographics, CAD risk factors, presenting symptoms, and laboratory tests, as well as postprocedural data were collected. The data were, subsequently, compared between the men and women. Results: Out of the 44,820 patients (16,378 women), who underwent coronary angiography, 37,358 patients (11,995 women) had CAD. Amongst the CAD patients, the females were not only significantly older, less educated, and more overweight than were the males but also had higher levels of triglyceride, cholesterol, low-density lipoprotein, highdensity lipoprotein, and fasting blood sugar (P< 0.001). Of all the risk factors, hypertension and diabetes mellitus showed the strongest association in our female CAD patients (OR=3.45, 95%CI: 3.28-3.61 and OR=2.37, 95%CI: 2.26- 2.48, respectively). Acute coronary syndrome was more prevalent in the men (76.1% vs. 68.6%, P< 0.001), and chronic stable angina was more frequent in the females (31.4% vs. 23.9%, P< 0.001). With respect to post-procedural recommendations, the frequency of recommendations for non-invasive modalities was higher in the females (20.1% vs. 18.6%, P< 0.001). Conclusion: Hypertension and diabetes mellitus had the strongest association with CAD in our female patients. In the extensive CAD patients, medical treatment was recommended to the women more often.
|
|
| 27. |
- Abbasi, Seyed Hesameddin, et al.
(author)
-
Mortality from Acute Coronary Syndrome: Does Place of Residence Matter?
- 2022
-
In: Journal of Teheran University Heart Center. - : Tehran University of Medical Sciences. - 1735-8620 .- 2008-2371. ; 17:2, s. 56-61
-
Journal article (peer-reviewed)abstract
- Background: Current evidence shows inequality in the outcomes of rural and urban patients treated at their place of residence. This study compared in-hospital mortality between rural and urban patients with acute coronary syndrome (ACS) to find whether there were differences in the outcome and received treatment.Methods: Between May 2007 and January 2018, patients admitted with ACS were included. The patients’ demographic, clinical, and laboratory data, as well as their in-hospital medical courses, were recorded. The association between place of residence (rural/urban) and in-hospital mortality due to ACS was evaluated using logistic regression adjusted for potential confounders.Results: Of 9088 recruited patients (mean age =61.30±12.25 y; 5557 men [61.1%]), 838 were rural residents. A positive family history of coronary artery disease (P=0.003), smoking (P=0.002), and hyperlipidemia (P=0.026), as well as a higher body mass index (P=0.013), was seen more frequently in the urban patients, while the rural patients had lower education levels (P<0.001) and higher unemployment rates (P=0.009). In-hospital mortality occurred in 135 patients (1.5%): 10 rural (1.2%) and 125 urban (1.5%) patients (P=0.465). The Firth regression model, used to adjust the effects of possible confounders, showed no significant difference concerning in-hospital mortality between the rural and urban patients (OR, 1.57; 95% CI, 0.376 to 7.450; P=0.585).Conclusion: This study found no significant differences in receiving proper treatment and in-hospital mortality between rural and urban patients with ACS.
|
|
| 28. |
|
|
| 29. |
- Abbasi, Seyed, et al.
(author)
-
Socioeconomic status and in hospital mortality of acute corony syndrome: Can education and occupation serves as preventive measures?
- 2015
-
In: International Journal of Preventive Medicine. - : Medknow. - 2008-7802 .- 2008-8213. ; 6
-
Journal article (peer-reviewed)abstract
- Background: Socioeconomic status (SES) can greatly affect the clinical outcome of medical problems. We sought to assess the in‑hospital mortality of patients with the acute coronarysyndrome (ACS) according to their SES.Methods: All patients admitted to Tehran Heart Center due to 1st‑time ACS between March 2004 and August 2011 were assessed. The patients who were illiterate/lowly educated (≤5 years attained education) and were unemployed were considered low‑SES patients and those who were employed and had high educational levels (>5 years attained education) were regarded as high‑SES patients. Demographic, clinical, paraclinical, and in‑hospital medical progress data were recorded. Death during the course of hospitalization was considered the end point, and the impact of SES on in‑hospital mortality was evaluated.Results: A total of 6246 hospitalized patients (3290 low SES and 2956 high SES) were included (mean age = 60.3 ± 12.1 years, male = 2772 [44.4%]). Among them, 79 (1.26%) patients died. Univariable analysis showed a significantly higher mortality rate in the low‑SES group (1.9% vs. 0.6%; P < 0.001). After adjustment for possible cofounders, SES still showed a significant effect on the in‑hospital mortality of the ACS patients in that the high‑SES patients had a lower in‑hospital mortality rate (odds ratio: 0.304, 95% confidence interval: 0.094–0.980; P = 0.046).Conclusions: This study found that patients with low SES were at a higher risk of in‑hospital mortality due to the ACS. Furthermore, the results suggest the need for increased availability of jobs as well as improved levels of education as preventive measures to curb the unfolding deaths owing to coronary artery syndrome.
|
|
| 30. |
- Abbasian, Saeid, et al.
(author)
-
Attitudes towards participation in business development programmes : An ethnic comparison in Sweden
- 2015
-
In: European Journal of Training and Development. - UK : Emerald Group Publishing Limited. - 2046-9012 .- 2046-9020. ; 39:1, s. 59-75
-
Journal article (peer-reviewed)abstract
- Purpose – The aim of the study is to investigate whether there are any differences between the attitudes towards participation in development programmes of entrepreneurs who are immigrants and those who are native-born. Design/methodology/approach – Several statistical methods, including a binary logistic regression model, were used to analyse a unique, firm-level dataset collected by the Swedish Small Business Forum in October and November 2012. The dataset was based on a questionnaire composed of 60 closed questions that was completed by 531 participants representing 395 companies. Findings – Based on the analysis of 15 different attitude variables, the empirical findings are that immigrant managers/owners are more likely to show a positive attitude to participation in development programmes, in terms of nine of those attitude variables, than their native counterparts. Because there are no data about second generation of immigrants in the sample, thus, this category may have had an impact on the results. However, there is no possibility to identify any impact on the results. Originality/value – There is no prior research focusing specifically on this question, and to the authors' knowledge, this study is the first that has attempted to deal with the issue. This study is based on a recent and unique database, and provides new evidence on the relationship between ethnicity and attitude towards participation in development programmes among entrepreneurs. Its context is different from that of prior research.
|
|
