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Background/aim: The aim of this paper was to determine the general tendencies of urology patients and effect of COVID-19 pandemic on daily urological practice at tertiary centers located in the most affected area in Turkey. Materials and methods: We retrospectively analyzed the data of 39,677 patients (group 1) that applied to 6 different large-volume tertiary centers in İstanbul for outpatient consultation, surgery, or other procedures in the 3-month period between March 16 and June 14, 2020. The distribution of the number of patients who applied to subspecialty sections of urology outpatient clinics and inpatient services were recorded by weeks. That data was compared to data obtained from 145,247 patients that applied to the same centers in the same period of the previous year (group 2). The reflection of worldwide and Turkish COVID-19 case distribution on the daily urological practice was analyzed. Results: There was a decrease in the number of patients in all subspecialty sections the in group 1 compared to group 2; however, there was a significant proportional increase in urooncology and general urology admissions. A decrease of approximately 75% was observed in the total number of surgeries (p < 0.001). We detected a negative correlation between the numbers of admission to all outpatient clinics and COVID-19 cases or deaths in Turkey (p < 0.05). The same negative correlation was present for all surgical procedures and consultations (p < 0.05). The multivariate linear regression analysis revealed that the number of cases in Turkey, and the number of deaths worldwide affect the number of outpatient clinic admissions (R2 = 0.38, p = 0.028) and urological surgery (R2 = 0.33, p = 0.020) in Turkey negatively. Conclusion: This novel pandemic has implications even for urology practice. Urological surgical procedures were more affected by COVID-19-related deaths in Turkey and worldwide. Outpatient admissions and urological surgeries decreased significantly by increasing COVID-19 case numbers in Turkey and worldwide deaths. [ABSTRACT FROM AUTHOR]

This paper deals with the exergoeconomic analysis of a 750-Wp solar photovoltaic (PV) system that is constructed at the Meteorology Park of İstanbul Technical University (41.102° N, 29.02° E) in Istanbul, Turkey. It is known that seasonal differences cause a variation in the exergoeconomic parameters (energy and exergy loss rates) of solar PV systems. Due to this perspective, for regional climatic parameters 2 months are selected: April to represent the spring and August to represent the summer. Within this research, first the exergy analysis is performed on the system and then the economic values of the results are evaluated using the exergy, cost, energy, and mass (EXCEM) method. The energy efficiency of the considered system in August and April varies between 4.5% and 7.3% and 5.5% and 8.5%, respectively. Additionally, the exergy efficiency of the system in August and April varies between 3% and 5.3% and 3.8% and 6.5%, respectively. The average unit cost of the exergy values for August and April are calculated based on the EXCEM model as 0.214 W/$ and 0.129 W/$. Moreover, the average unit cost of the energy values for August and April are estimated as 0.222 W/$ and 0.134 W/$, respectively. [ABSTRACT FROM AUTHOR]