206 research outputs found

    Fractal analysis of spatio-temporal changes of forest cover in Istanbul, Turkey

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    In this study, the spatio-temporal changes in forest cover in Istanbul, one of the provinces with the most changes in forest areas in Turkey due to the pressure of urbanization and industrialization, were investigated using fractal analysis. The areal changes and changes in spatial patterns were determined to assess the spatio-temporal changes in the period 2000–2017. Fragmentation/compactness and heterogeneity/homogeneity of forest cover were determined by fractal dimension and lacunarity index, respectively. The results show that the forest areas have significantly decreased and become more fragmented and heterogeneous. In conclusion, this study reveals that fractal analysis can provide considerable information in the examination and interpretation of spatial changes in forest areas

    Assessment of urban sprawl using Shannon’s entropy and fractal analysis: a case study of Atakum, Ilkadim and Canik (Samsun, Turkey)

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    Urban sprawl is one of the most important problems in urban development due to its negative environmental and societal impacts. Therefore, the spatial pattern of urban growth should be accurately analyzed and well understood for effective urban planning. This paper focuses on urban sprawl analysis in the Atakum, Ilkadim and Canik districts of Samsun, Turkey. In this study, urban sprawl was examined over a period of 24 years using Shannon's entropy and fractal analysis based on remote sensing and Geographic Information System (GIS). The built-up areas in 1989, 2000 and 2013 were extracted from Landsat TM/ETM+/OLI images using the maximum likelihood classification method, and urban form changes in the 1989–2013 period were investigated. The Shannon's entropy method was used to determine the degree of urban sprawl, and a fractal analysis method based on box counting was used to characterize the urban sprawl. The results show that Atakum, Ilkadim and Canik experienced important changes and have considerable sprawl and complex characteristics now. The study also revealed that there is no monotonic relationship between Shannon's entropy and fractal dimension

    Modelling spatial changes in coastal areas of Samsun (Turkey) using a Cellular Automata-Markov Chain method

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    Promjene gradova kroz određeni vremenski period i određivanje relevantnih trendova važni su za simuliranje odgovarajućeg razvoja i planiranja grada. U priobalnim područjima naročito dolazi do izražaja intenzivni pritisak za izgradnjom, razvojem turizma, trgovine i industrije od strane velepoduzetnika, institucija i poduzeća koja se bave izgradnjom. Zbog nesposobnosti usmjeravanja razvoja i jačanja kontrole ubrzano dolazi do uništavanja prirodnih resursa u priobalnim područjima. Stoga je određivanje tih trendova ključno za osiguranje zaštite prirodnih resursa i planiranog razvoja. Budući da nije moguća potpuna procjena urbanog širenja, vjerojatne se promjene mogu odrediti simulacijama. U ovom se radu simulacija 30-godišnjeg urbanog širenja (2004-2034) dobila prema podacima o korištenju zemljišta/izgrađenosti zemljišta - land use/land cover (LU/LC) iz 1987 i 2004 za Samsun, priobalna područja Turske, uz primjenu metode Stanični automati-Markovljev lanac (CA-Markov). Kako bi se provjerila ta metoda, simulacija urbanog širenja za 2014. uspoređena je sa stvarnim LU/LC podacima za istu godinu te je dobivena kappa vrijednost od 0,82. Za određivanje LU/LC korištene su satelitske slike, a analize su izvršene u okruženju geografskog informacijskog sustava (GIS). Pokazalo se da je pristup CA-Markovljev lanac integriran s GIS i daljinskim očitavanjem učinkovit u analizi dinamike urbanog rasta. Primjenom simulacije za 2034. godinu, vjerojatnost urbanog širenja u periodu 2014-2034 procijenjena je kao približno 3683 ha, a predviđeno je vjerojatno uništenje apsolutno poljoprivrednog zemljišta, šuma i pašnjaka od približno 968 ha, odnosno 228 ha i 24 ha.The evolution of cities over a specific time period and the determination of relevant trends are important to simulate for the proper development and planning of a city. In particular, coastal areas experience intense pressure from developers with respect to settlements, tourism, trade and industry, and built-up areas are being observed near coasts. The inability to direct development and control growth is destroying natural resources in coastal areas at a rapid pace. Thus, determining these trends is the key component for ensuring the protection of natural resources and planned growth. Because a complete estimation of urban expansion is not possible, likely changes can be determined using simulations. In this study, a 30-year urban expansion simulation (2004-2034) was obtained using land use/land cover (LU/LC) data for 1987 and 2004 at Samsun (Turkey) coastal areas and using the Cellular Automata-Markov Chain (CA-Markov) method. To verify the method, urban expansion simulation for the year 2014 was compared with real LU/LC data for the same year, and the kappa value was found to be 0,82. To determine LU/LC, Landsat TM/ETM+/OLI satellite images were used, and the analyses were realised in a geographic information system (GIS) environment. As a result of the study, the CA-Markov Chain approach integrated with GIS and remote sensing was shown to be effective in the study of urban growth dynamics. Using the simulation for the year 2034, probable urban expansion in the 2014-2034 period was estimated as approximately 3683 ha and the probable destructions of absolute agricultural lands, forests and pastures were predicted as approximately 968 ha, 228 ha and 24 ha, respectively

    Neutrophil/lymphocyte ratio and Red blood cell distribution width are independent risk factors for 30-day mortality in Gastrointestinal system bleeding patients

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    Background. In this study, we aimed to examine demographic and endoscopic features of patients with GI bleeding to determine the factors affecting 30-day mortality. Method. Patient’s demographic features, laboratory outcomes, comorbidities, drug use, endoscopy outcomes, Glasgow-Blatchford scores, and mortality status were examined. The factors affecting 30-day mortality were investigated. Results. The mean age of the patients was 58.2±17.4 years, and 72.1% were male patients. 30-day mortality rate was found to be 14.4%. The mean age of patients who died was high (p0.05). Urea, neutrophils, red blood cell distribution width / platelet ratio, neutrophil / lymphocyte ratio and RDW levels were high, and hemoglobin level was significantly low in patients with a mortal progression (p0.05). Glasgow-Blatchford score was significantly higher in patients who died (p<0.05). Conclusion. Many factors affect 30-day mortality in GI bleeding. It should be remembered that follow-up of patients with an advanced age who have comorbidity and impaired hemodynamics should be kept for long, and that these patients are at a high risk for mortality. According to our results, NLR and RDW are independent factors that determine the 30-day mortality in upper GI bleeding

    Stężenia adropiny i albuminy modyfikowanej niedokrwieniem w surowicy w zależności od występowania zespołu policystycznych jajników i wartości BMI

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    Introduction: The aim of this study was to evaluate the effects of polycystic ovary syndrome (PCOS) and body mass index (BMI) on serum adropin and ischemia modified albumin (IMA) levels. Materials and methods: This prospective cross-sectional study was performed with a total of 120 women [group1; non-PCOS = 60 (BMI < 25 = 30, BMI ≥25 = 30) and group 2; PCOS = 60 (BMI < 25 = 30, BMI ≥25 = 30)]. Blood samples were collected between the third and fifth days of the women’s menstrual cycles after a night of fasting. Results: There were no differences between the groups in relation to age, basal follicle stimulating hormone, estradiol, thyroid stimulating hormone, prolactin, high-density lipoprotein cholesterol, total testosterone, dehydroepiandrosterone sulfate levels, systolic and diastolic blood pressures. A significant difference was found in basal luteinizing hormone, fasting glucose, insulin, homeostatic model assessment of insulin resistance, total cholesterol, low-density lipoprotein cholesterol, triglycerides, free testosterone levels, waist-to-hip ratios and the Ferriman-Gallwey scores between the PCOS and non-PCOS patients in the lean and overweight groups (p < 0.05). The serum adropin levels in the lean PCOS group were lower than in the lean non-PCOS group (p < 0.05) and were lower in the overweight PCOS group than in the overweight non-PCOS group (p < 0.05). There was also a statistically significant difference in serum IMA levels in the PCOS group than in the non-PCOS group in both the lean and overweight groups (p < 0.05). Conclusions: Although serum adropin levels were significantly decreased in the PCOS group, IMA levels increased. Further studies are needed to determine the effects of adropin and IMA in women with PCOS and to use a new marker to monitorize treatment outcomes. Wstęp: Badanie przeprowadzono w celu oceny wpływu zespołu policystycznych jajników (polycystic ovary syndrome, PCOS) i wskaźnika masy ciała (body mass index, BMI) na surowicze stężenia adropiny i albumin modyfikowanej niedokrwieniem (ischemia modified albumin, IMA). Materiał i metody: To prospektywne badanie przekrojowe obejmowało 120 kobiet [grupa 1: osoby bez PCOS — n= 60 (BMI &lt; 25 — n= 30; BMI ≥ 25 — n = 30) oraz grupa 2: osoby z PCOS — n= 60 (BMI &lt; 25 — n= 30, BMI ≥ 25 —n = 30)]. Próbki krwi pobierano między trzecim a piątym dniem cyklu menstruacyjnego badanych kobiet, rano na czczo. Wyniki: Grupy nie różniły się pod względem wieku, podstawowego stężenia hormonu folikulotropowego, stężeń estradiolu, tyreotropiny, prolaktyny, cholesterol frakcji HDL, testosteronu całkowitego i siarczanu dehydroepiandrosteronu ani skurczowego i rozkurczowego ciśnienia tętniczego. Stwierdzono natomiast istotne różnice między grupą z PCOS i bez PCOS w podgrupach osób szczupłych i otyłych w zakresie podstawowego stężenia hormonu luteinizującego, glikemii na czczo, wskaźnika insulinooporności w modelu homeostazy, stężeń cholesterolu całkowitego, cholesterolu frakcji LDL, triglicerydów i wolnego testosteronu, a także wskaźnika talia-biodra oraz oceny w skali Ferrimana-Gallweya (P &lt; 0,05). Stężenia adropiny w osoczu były niższe w grupie szczupłych kobiet z PCOS niż u szczupłych osób niechorujących na PCOS (P &lt; 0,05) oraz były niższe u otyłych osób z PCOS niż u otyłych osób z grupy bez PCOS (P &lt; 0,05). Stwierdzono również statystycznie istotną różnice w stężeniach IMA w surowicy między kobietami z PCOS i bez PCOS, zarówno w podgrupie osób szczupłych, jak i otyłych (P &lt; 0,05). Wnioski: Mimo że surowicze stężenia adropiny były istotnie niższe w grupie z PCOS, stężenia IMA były podwyższone w tej grupie badanych. Konieczne są dalsze badania w celu określenia wpływu adropiny i IMA u kobiet z PCOS i stosowanie nowych wskaźników do monitorowania efektów leczenia

    Usefulness of the uric acid and CHA2DS2-VASc score in prediction of left atrial thrombosis in patients with mitral stenosis and sinus rhythm

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    Background: The risk of thrombus formation in the left atrium is known to be very high in patients with both mitral stenosis (MS) and atrial fibrillation (AF). However, that risk should not be ignored in patients with MS in sinus rhythm (SR). The aim of this study was to determine the clinical, echocardiographic, and biochemical factors that could have a determining role in the formation of a left atrial (LA) thrombus in patients with MS in SR. Method: A total of 207 consecutive patients with MS who underwent both transthoracic echocardiography (TTE) and transesophageal echocardiography (TEE) for diagnosis or to investigate the presence of a thrombus in the LA and appendage were enrolled in this study. Results: LA thrombus was detected in 21 of 207 patients. CHA2DS2-VASc score was not found to be a predictor of LA thrombosis in patients with MS in SR, despite the higher CHA2DS2-VASc scores observed in those patients. The mitral valve area and mitral valve gradient were not predictive of LA thrombus development; however, LA anteroposterior diameter (LAAPD) was found to be a predictor of LA thrombosis. Levels of high sensitivity-C-reactive protein and uric acid were higher in the patients with LA thrombosis, but only uric acid was found to be a predictor of LA thrombosis in multivariate analysis. Conclusions: A larger LAAPD and an elevated serum uric acid level were found to be independent predictors of LA thrombosis in patients with MS in SR.

    Assessment of the relationship between a narrow fragmented QRS complex and coronary slow flow

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    Background: The coronary slow flow (CSF) phenomenon is a delayed antegrade progression of contrast agent to the distal branch of a coronary artery in the absence of obstructive coronary artery disease (CAD). A narrow fragmented QRS (fQRS) has been reported as a significant predictor of sudden cardiac death in patients with idiopathic dilated cardiomyopathy. The present study aimed to investigate the relationship between a narrow fQRS on the admission electrocardiogram (ECG) and CSF on coronary angiography. Methods: This study included 165 consecutive patients (112 CSF, 53 controls) who underwent first-time diagnostic conventional coronary angiography for suspected CAD. Coronary flow was quantified by thrombolysis in myocardial infarction (TIMI) frame count (TFC). The patients were divided into two groups according to the presence or absence of a narrow fQRS complex on the admission ECG. Results: Forty four patients were in the fQRS group (mean age, 52.97 ± 3.13 years). There was no difference between the two groups with respect to age, gender, body mass index, family history, hyperlipidemia, hypertension, or diabetes mellitus. The extent of CSF was significantly greater in the fQRS group compared to the non-fragmented group (p &lt; 0.001). A significant correlation was also found between mean TFC values and fQRS (p &lt; 0.001). On multivariate analysis, only CSF (p = 0.03) was a significant independent predictor for narrow fQRS, after adjustment for other parameters. Conclusions: The narrow fQRS is a simple, inexpensive, and readily available noninvasive ECG parameter that may be a new potential indicator of myocardial damage in patients with CSF.

    Short-term effects of transcatheter aortic valve implantation on left atrial appendage function

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    Background: The beneficial effects of the transcatheter aortic valve implantation (TAVI) on echocardiographic parameters including left atrial (LA) and left ventricular (LV) functions were described by previous studies. The aim of this study was to analyze the effects of TAVI on left atrial appendage (LAA) function assessed by transthoracic and transesophageal echocar­diography. Methods: Fifty-five patients with severe symptomatic aortic stenosis were included in this prospective study. LAA early and late emptying velocities, LAA filling velocity, peak early diastolic (EM), late diastolic (AM), and systolic (SM) velocities were measured with pulsed wave Doppler and tissue Doppler imaging, and E/Em ratio was calculated before and 7.1 ± 2.8 days after TAVI. A subgroup analysis was performed in accordance with the left ventricular ejection fraction (LVEF) of the patients and the severity of their LV diastolic dysfunction. Results: Although the post-procedure peaks and mean gradients of the patients decreased sig­nificantly, the LVEF increased significantly in those who had low LVEF before the procedure. The post-procedure E/Em ratio decreased significantly (p &lt; 0.001). The post-procedural LAA mean filling velocity and EM velocity were significantly higher than the pre-procedural filling velocity (p &lt; 0.001, p = 0.002, respectively). In the subgroup analysis, the post-procedural LAA filling velocity, early and late LAA emptying velocities, in addition to the mean velocity of the EM, AM, and SM were significantly higher than before the procedure in patients with LVEF of &lt; 50% and E/Em ratios of &gt; 15. Conclusions: LAA function improved soon after the TAVI procedure, especially in patients with low LVEF and marked LV diastolic dysfunction

    The diagnostic value of serum copeptin levels in an acute pulmonary embolism

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    Background: Acute pulmonary embolism (APE) is a common disease which is associated with high mortality and morbidity. Circulating level of copeptin, which was demonstrated to be elevated in heart failure, acute myocardial infarction and pulmonary arterial hypertension, were reported to be independent predictors of poor outcome in recent studies. The aim of the present study was to investigate the clinical utility of copeptin in the diagnosis of APE. Methods: A total of 90 consecutive patients, admitted to emergency service due to acute chest pain and/or dyspnea and who underwent pulmonary computerized tomography angiography (CTA) due to suspicion of APE, were included in this prospective study. The patients diagnosed with APE were defined as APE (+) group and the remaining individuals with normal pulmonary CTA result were defined as APE (–) group. Results: Copeptin levels (7.76 ± 4.4 vs. 3.81 ± 1.34 ng/dL; p &lt; 0.001) were higher in the APE (+) group as compared to the APE (–) group. Copeptin was significantly positively correlated with B-type natriuretic peptide (r = 0.434, p &lt; 0.001), D-dimer (r = 0.315, p = 0.003) and troponin I (r = 0.300, p = 0.004) and inversely correlated with arterial oxygen saturations (r = –0.533, p &lt; 0001). When the correlation of copeptin with right ventricular dysfunction parameters was investigated, it was significantly inversely correlated with the tricuspid annular plane systolic excursion (r = –0.521, p &lt; 0.001) and positively correlated with right to left ventricle ratio (r = 0.329, p = 0.024). Copeptin (OR 1.836, 95% CI 1.171–2.878, p = 0.008) was found as a significant independent predictor of APE in a multivariate analysis, after adjusting for other risk parameters.  Conclusions: Copeptin is a promising new biomarker, which may be used to support the need for further investigations and to improve the diagnosis of patients with APE.
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