The performance of electricity generation plants in Turkey are analyzed and compared. The data set contains inputs from 65 thermal, hydro and wind power plants, owned by private and public sectors. ...Data envelopment analysis (DEA) is used as the primary mathematical tool. Two efficiency indexes, reflecting operational and investment performance, are defined and pursued. Constant returns to scale, variable returns to scale and assurance region type DEA models are used in the analysis. Scale efficiency is also considered. Performance comparisons include public versus private sector plants, and natural gas versus coal versus oil fired plants. Also, relationships between efficiency scores and various input/output factors are investigated and some interesting trends are identified.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Objective: This study’s main goal was to evaluate the possible impact of different-sized double-J (DJ) stents on the pain and stone-free status following flexible ureteroscopic laser disintegration ...(fURS) of renal stones. Material and Methods: A total of 104 patients who underwent fURS for kidney stones were included in our study. In 51 patients, a 4.7 Fr DJ stent was used after stone fragmentation, while in the remaining 53 cases, a 6 Fr stent was chosen. Between the two groups, general pain symptoms were evaluated using a visual pain scale at the end of the first postoperative week. The stone-free status was evaluated using non-contrast computed tomography (NCCT) after three months following surgery. Success was determined by either the complete clearance of the stones or the presence of small stone fragments (<3 mm). Results: Using a visual pain scale, we compared the two groups’ overall reports of pain (4.02±1.10 vs 4.81±1.53, p=0.006). When we looked at the stone-free rates, the two groups were not significantly different in this regard (84.3% vs 74.5%, p=0.264). We found no statistically significant difference between the two groups in terms of postoperative fever, stent migration, or visits to the emergency room. Conclusion: In spite of the fact that larger diameter stents resulted in more pain complaints for patients, they did not alter the long-term stone-free rates appreciably, as evidenced by our findings. In order to reduce the occurrence of unpleasant symptoms, a 4.7 Fr double-j stent may be preferable over a 6 Fr stent following flexible ureteroscopic surgery. Keywords: Double-j stent diameter, renal stones, flexible ureterorenoscopy, stone free
In this study, a model is developed to investigate the implications of an hourly day-ahead competitive power market on generator profits, electricity prices, availability and supply security. An ...integrated simulation/optimization approach is employed integrating a multi-agent simulation model with two alternative optimization models. The simulation model represents interactions between power generator, system operator, power user and power transmitter agents while the network flow optimization model oversees and optimizes the electricity flows, dispatches generators based on two alternative approaches used in the modeling of the underlying transmission network: a linear minimum cost network flow model and a non-linear alternating current optimal power flow model. Supply, demand, transmission, capacity and other technological constraints are thereby enforced.
The transmission network, on which the scenario analyses are carried out, includes 30 bus, 41 lines, 9 generators, and 21 power users. The scenarios examined in the analysis cover various settings of transmission line capacities/fees, and hourly learning algorithms. Results provide insight into key behavioral and structural aspects of a decentralized electricity market under network constraints and reveal the importance of using an AC network instead of a simplified linear network flow approach.
► An agent-based simulation model with an AC transmission environment with a day-ahead market. ► Physical network parameters have dramatic effects over price levels and stability. ► Due to AC nature of transmission network, adaptive agents have more local market power than minimal cost network flow. ► Behavior of the generators has significant effect over market price formation, as pointed out by bidding strategies. ► Transmission line capacity and fee policies are found to be very effective in price formation in the market.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
With the recent shale gas boom, the U.S. is expected to have very large natural gas resources. In this respect, the key question is would it be better to rely completely on free market resource ...allocations which would lead to large exports of natural gas or to limit natural gas exports so that more could be used in the U.S.. After accounting for the cost of liquefying the natural gas and shipping it to foreign markets, the current price difference leaves room for considerable profit to producers from exports. In addition, there is a large domestic demand for natural gas from various sectors such as electricity generation, industrial applications, and the transportation sector etc. A hybrid modeling approach has been carried out using our version of the well-known MARket ALlocation (MARKAL)-Macro model to keep bottom-up model richness with macro effects to incorporate price and gross domestic product (GDP) feedbacks. One of the conclusion of this study is that permitting higher natural gas export levels leads to a small reduction in GDP (0.04%-0.17%). Higher exports also increases U.S. greenhouse gas (GHG) emissions and electricity prices (1.1%-7.2%). We also evaluate the impacts of natural gas exports in the presence of a Clean Energy Standard (CES) for electricity. In this case, the GDP impacts are similar, but the electricity and transport sector impacts are different.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Objective: We compared the success and complication rates of retrograde intrarenal surgery (RIRS) performed with semi-rigid ureterorenoscopy (srURS) or flexible ureterorenoscopy (fURS) for isolated ...renal pelvic stones. Materials and Methods: A total of 247 patients who underwent RIRS with fURS (n=179; group 1) or srURS (n=68; group 2) were included in this study. Various factors related to patients, stones and surgical procedures were evaluated retrospectively. Results: There was no difference between the patient groups according to mean age (49.12+ or -1.10 years vs 49.59+ or -1.60 years, p=0.745), gender distribution (p=0.152), mean hounsfield unit values (941+ or -31.41 vs 1036+ or -44.47 p=0.077), and mean hospitalization time (3.57+ or -0.19 days vs 4.59+ or -0.57, p=0.224). In group 1, the mean stone size (14.5+ or -0.73 mm vs 15.5+ or -0.62 mm, p=0.019) was statistically lower and the operative time (79.73+ or -3.38 min vs 70.65+ or -8.61, p=0.041) was statistically higher than those of group 2. The overall success rate in group 1 and group 2 was 93.9% and 63.6%, respectively (p<0.0001). The complication rate in group 2 (23.5%) was higher than that of the group 1 (12.3%) (p=0.047). Conclusion: According to our results, the success rate of srURS was lower and the complication rate was higher than that of fURS. Therefore, we conclude that srURS was unsafe and unsuccessful for use in the treatment of pelvic stones. Prospective studies involving intrarenal pressure measurement and cost analysis must reach a conclusion in this respect. Keywords: Urolithiasis, nephrolithiasis, ureteroscopy, retrograde intrarenal surgery
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Objective: To evaluate the level of knowledge of autonomic dysreflexia among physicians practicing in different disciplines namely anesthesia and reanimation, emergency, neurology, neurosurgery, ...urology, and physical medicine and rehabilitation departments.
Materials and Methods: The study was conducted using a questionnaire consisting of seven questions, which was completed in a prospective manner by 95 physicians (residents and consultants) in our tertiary care hospital.
Results: None of the questions asked in the questionnaire could be replied by 38 (40%) of 95 physicians in the hospital. Only one physician did reply all the questions completely. The mean value of the mark given was 2.00±2.04 for consultants and 1.10±1.37 for residents (p=0.039). Our data showed that while only 27% of the physicians have received training on autonomic dysreflexia; 18% of physicians had a previous experience with patients having autonomic dysreflexia.
Conclusion: Taking the potential serious complications of autonomic dysreflexia into account, necessary information on this emergency status should be given to physicians. We believe that to reach a more precise conclusion about awareness of physicians on autonomic dysreflexia, multicenter studies with larger number of participants are certainly necessary.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Spontaneous renal or other organ ruptures secondary to anticoagulants have rarely been reported. The clinical features of renal rupture include
acute flank/abdominal pain, haematuria, hypotension and ...shock. It can occur due to increased intraabdominal pressure during coughing. Rupture is
most commonly caused by renal tumors such as angiomyolipomas. In the literature, other known causes are long-term haemodialysis, arteriosclerosis
or arteritis. Wunderlich’s syndrome is an extremely dangerous complication that may cause death if not treated intensively. If the haemorrhage is
self-limiting and the patient is responsive to fluid replacement, the patient can be managed conservatively. Selective angiographic embolization and
emergency nephrectomy (partial or total) are the treatment options. In the literature, we found only one case that was presented as spontaneous
non-traumatic renal rupture associated with coughing. In our case, total nephrectomy had to be performed, but it was not adequate.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Çalışma boyunca Türkiye’deki çeşitli enerji santrallerinin operasyonel ve uzun vadeli yatırım performansları Stokastik Sınır Analiz (SSA) ve Veri Zarflama Analizi (VZA) kullanılarak karşılaştırıldı. ...Veri kümesi, özel ve kamu mülkiyetindeki 65 termal, hidroelektrik ve rüzgâr enerji santrallerinden oluşturuldu. Operasyonel ve yatırım performansını yansıtan verimlilik endeksleri ortaya konup incelendi. Analizde ölçek, sabit ve değişken, güvence bölgesi, gevşek tabanlı ölçüm, sistem karşılaştırma ve bilateral tip DEA modelleri ile Cobb-Douglas ve Translog üretim fonksiyonlarını kullanan stokastik sınır analizi kullanıldı. Ölçek getirisinin analizine yönelik VZA ve SSA modellerinin ortaya koyduğu tüm indisler kullanılarak değerlendirmeler yapıldı. Kamu-özel, termal-yenilenebilir karşılaştırmalarının yanı sıra doğal gaz-kömür-petrol santralleri verimlilik performans değerlerine göre karşılaştırıldı. VZA ve SSA metotlarından elde edilen sonuçlar karşılaştırıldı. İlginç verimlilik endeksi ve çeşitli giriş/çıkış faktörleri arasında ilişkiler ortaya kondu ve değerlendirildi. Doğal gazla çalışan elektrik santralleri, yatırım verimliliği açısından kömürle çalışan santrallerden daha iyi performans gösterse de, değişken getiri oranlarına göre operasyonel performansı için tersi geçerlidir.
Purpose of Review
To present the latest evidence related to the predictors of urinary tract infections (UTIs) and urosepsis after ureteroscopy (URS) for stone disease.
Recent Findings
Our review ...suggests that almost half of all post-URS complications are related to infectious complications although reported rates of urosepsis were low. The use of antibiotic prophylaxis, treatment of pre-operative UTI, and low procedural time seem to reduce this risk. However, the risk is higher in patients with higher Charlson comorbidity index, elderly patients, female gender, long duration of pre-procedural indwelling ureteric stents and patients with a neurogenic bladder and with high BMI.
Summary
Infectious complications following ureteroscopy can be a source of morbidity and potential mortality. Although majority of these are minor, efforts must be taken to minimise them especially in high-risk patients. This includes the use of prophylactic antibiotics, limiting stent dwell and procedural time, prompt identification and treatment of UTI and urosepsis, and careful planning in patients with large stone burden and multiple comorbidities.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
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