236 research outputs found
Yüksek çözünürlüklü uydu görüntülerinin geometrik doğruluk yönünden incelenmesi
The high quality level that high resolution satellite images have reached in the last years has proved that these images could be a useful data source for the production of orthophoto images and different mapping products. Specifically, it is very important in areas where aerial photogrammetry is not possible or feasible due to political reasons / restrictions and mapping frequency constrained by the limits of flight planning. Research activities about high resolution satellite images have been mainly focusing on the geometric accuracy aspects in ortho-image generation and Digital Elevation Model (DEM) extraction. In addition to these activities, some researches are increasingly concentrating on feature detection, recognition and reconstruction studies like automated mapping of roads, extraction of 3D buildings and cadastral mapping. There are two important criteria for quality assessment of the images; geometric accuracy and object definition. When we take the mapping processes into consideration, these criteria are basically dependent on the relation between pixel size and the map scale, contrast information (spectral range and colour), atmosphere and the sun elevation, the printing technology and the resolution of the human eye in a usual reading distance. A study has been implemented in Gölbaşı near Ankara, which has 10 km X 10 km area and a height difference about 440 m, for geometric accuracy assessment of high resolution satellite images. 12 ground control points were revised and signalized before the recording of images. Stereo-pair Ikonos (dated August 4th, 2002) and mono Quickbird (dated May 26th, 2002) images and 1/16000 scaled aerial photographs (dated August 29th, 2002) have been provided by Inta (Turkey), Eurimage (Italy) and General Command of Mapping (Turkey) free of charge. For geometric accuracy assessment; different digital elevation models (DEM’s) have been created using photogrammetric and cartographic methods. Photogrammetric DEM has been produced using 1/16000 scaled stereo aerial photographs and has accuracy about 1 m. From the other side, cartographic DEM has been produced digitizing map contours and has accuracy about 5 m. And lastly, Ikonos DEM has been produced from stereo-pair Ikonos images automatically and has accuracy about 2 m. With these models, various orthophoto and mosaic images have been produced using ground control points. Used ground control points have had different distributions and number of points between 0 and 11. Well-recognized 27 checkpoints such as road junctions and field corners have been selected and measured with GPS. Planimetric coordinates of the checkpoints were measured on all orthophoto, mosaic and stereo images. These coordinates have been compared with GPS coordinates. From the comparison of these measurements, the differences and also the errors have been obtained. Afterwards the gross error positions have been evaluated according to ground control points’ network. The geometric accuracy results show that IKONOS - DEM can be used instead of photogrammetric DEM, the quality of GCP’s is as important as the number of GCP’s, systematic errors have occured in the easting / north easting (across track) direction and IKONOS images have better accuracy than Quickbird images when using direct sensor orientation parameters. Also we can say that the high resolution satellite images can be used in mid / large also from 1/6000 to 1/10000 scale map productions and these results are harmonious with the examples given in the literature. Actually there is nearly a consensus among photogrammetry and remote sensing society that some mapping applications from high resolution space imagery can be realized in mid / large scale. In addition, in spite of increasingly concentrating by some researches on feature detection, recognition and reconstruction studies in high resolution satellite images, it can not be said that these images couldn’t reach to the level of aerial images in determining and identifying of small features in big scale maps (e.g. 1/5000) yet. Therefore the discussions about usage of high resolution space imagery in big scaled map production are still lasting. Keywords: High resolution, satellite images, orthophoto, control point, Digital Elevation Model (DEM).Yüksek çözünürlüklü uydu görüntülerinin son yıllarda eriştiği üstün kalite düzeyi, bu verilerin ortofoto görüntüler ve farklı haritacılık üretimleri konusunda iyi bir veri kaynağı olabileceğini kanıtlamıştır. Ancak günümüzde halen, yüksek çözünürlüklü uydu görüntülerinin büyük ölçekli harita üretim çalışmalarında kullanılabilmesine ilişkin tartışmalar sürmektedir. Bu nedenle, yüksek çözünürlüklü uydu görüntülerinin geometrik doğruluk yönünden incelenmesi amacıyla, 10 km x 10 km boyutlarında bir alana ve 440 m yükseklik farkına sahip olan Ankara yakınlarındaki Gölbaşı bölgesinde bir çalışma gerçekleştirilmiştir. Bu çalışma için 12 adet Yer Kontrol Noktası (YKN) tespit edilmiş ve görüntü alımından önce bu noktalar işaretlenmiştir. Daha sonra stereo Ikonos (4 Ağustos 2002 tarihli) ve mono Quickbird görüntüleri ile 1/16000 ölçekli stereo hava fotoğrafları (29 Ağustos 2002 tarihli) temin edilmiştir. Geometrik doğruluk çalışması için öncelikle fotogrametrik ve kartografik yöntemler ile Ikonos uydu görüntülerinden Sayısal Yükseklik Modelleri (SYM) elde edilmiş ve farklı sayı ve dağılımda bulunan YKN kullanılarak değişik özelliklere sahip ortofotolar üretilmiştir. Arazide belirgin olarak tespit edilebilen 27 adet bağımsız kontrol noktası (test noktası) seçilmiş ve bunların koordinatları GPS ile arazide ölçülmüştür. Bağımsız kontrol noktalarının GPS koordinatları, aynı noktaların tüm ortofoto görüntüler üzerinde okunan koordinatları ile karşılaştırılmış ve aradaki farklar belirlenmiştir. Geometrik doğruluk araştırmaları sonucunda yapılan değerlendirmeler, yüksek çözünürlüklü uydu görüntülerinin orta/büyük ölçekli (1/6000–1/10000) harita üretim çalışmalarında kullanılabileceğini göstermektedir. Anahtar Kelimeler: Yüksek çözünürlük, ortofoto, kontrol noktası, Sayısal Yükseklik Modeli (SYM)
Intermolecular Bonding of Hemin in Solution and in Solid State Probed by N K-edge X-ray Spectroscopies
X-ray absorption/emission spectroscopy (XAS/XES) at the N K-edge of iron protoporphyrin IX chloride (FePPIX-Cl, or hemin) has been carried out for dissolved monomers in DMSO, dimers in water and for the solid state. This sequence of samples permits identification of characteristic spectral features associated with the hemin intermolecular bonding. These characteristic features are further analyzed and understood at the molecular orbital (MO) level based on the DFT calculations
Chemical Composition of Ambrosia trifida Essential Oil and Phytotoxic Effect on Other Plants
This study aimed to identify the main components of an essential oil produced from leaves of Ambrosia trifida and to evaluate its potential allelopathic effect on seed germination and seedling growth of lettuce, watermelon, cucumber and tomato. The essential oil was obtained by hydrodistillation and characterized chemically by gas chromatography (GC) coupled with both mass spectrometry (MS) and flame ionization detector (FID). Total 69 compounds were identified, with limonene (20.7 %), bornyl acetate (15.0 %), borneol (14.7 %) and germacrene D (11.6 %) as the major components. The working solutions of the essential oil emulsified with Tween 20 and dissolved in distilled water were prepared at four concentration levels (0.01, 0.1, 0.5 % and 1 %, v/v). The results obtained showed that increase in essential oil concentration leads to decrease in seed germination, as well as shoot and radical length of lettuce, watermelon, cucumber and tomato. The obtained data revealed a highly significant effect (p lt 0.05) between control and 1 % and 0.5 % oil concentrations in all treatments. The essential oil of A. trifida exhibited more powerful phytotoxic effects on lettuce, watermelon and tomato than on cucumber regarding germination and early seedling growth.This is the peer-reviewed version of the article: Sarić-Krsmanović Marija, Gajić-Umiljendić Jelena, Radivojević Ljiljana, Rajković Miloš, Santrić Ljiljana, Đurović-Pejčev Rada, "Chemical Composition of Ambrosia trifida Essential Oil and Phytotoxic Effect on Other Plants" 17, no. 1 (2020):e1900508,
[https://doi.org/10.1002/cbdv.201900508]
oxygen K-edge X-ray absorption and emission spectroscopy on micro-jets
Oxygen K-edge X-ray absorption, emission, and resonant inelastic X-ray
scattering spectra were measured to site selectively gain insights into the
electronic structure of aqueous zinc acetate solution. The character of the
acetate ion and the influence of zinc and water on its local electronic
structure are discussed
Neutrophil to lymphocyte ratio as an indicative of diabetic control level in type 2 diabetes mellitus
Background: Type 2 diabetes mellitus is associated with chronic low
grade inflammation. One of the novel inflammatory markers is hemogram
derived neutrophil to lymphocyte ratio (NLR). Objective: We aimed to
compare NLR levels of diabetic subjects and healthy controls and to
observe possible correlation between NLR and HbA1c. Methods: Medical
data of type 2 diabetic subjects admitted to out-patient clinics of our
institution between April to July in 2017 were obtained from database
and retrospectively analyzed. Control group was chosen from healthy
subjects who visited our institution for a routine check-up.
Anthropometric measures, laboratory data, including, HbA1c, NLR were
recorded. Results: Median NLR of the type 2 DM group 2.44 (1.9) was
significantly elevated when compared to healthy controls (1.5 (0.9),
(p<0.001). In addition, a Pearson\u2019s correlation test revealed
that NLR was strongly correlated with age (r=0.26, p=0.008), fasting
plasma glucose (r=0.38, p<0.001), and HbA1c (r=0.49, p<0.001).
Conclusion: Elevated NLR in otherwise healthy subjects may be
indicative of underlying impaired glucose metabolism and moreover, NLR
should be used as a marker of diabetic control level in addition to
HbA1c in type 2 diabetic subjects. DOI:
https://dx.doi.org/10.4314/ahs.v19i1.35 Cite as: Duman TT, Aktas G,
Atak BM, Kocak MZ, Erkus E, H S. Neutrophil to lymphocyte ratio as an
indicative of diabetic control level in type 2 diabetes mellitus. Afri
Health Sci. 2019;19(1). 1602-1606.
https://dx.doi.org/10.4314/ahs.v19i1.3
Impacts of Conformational Geometries in Fluorinated Alkanes
Research of blood substitute formulations and their base materials is of high
scientific interest. Especially fluorinated microemulsions based on
perfluorocarbons, with their interesting chemical properties, offer
opportunities for applications in biomedicine and physical chemistry. In this
work, carbon K-edge absorption spectra of liquid perfluoroalkanes and their
parent hydrocarbons are presented and compared. Based on soft X-ray
absorption, a comprehensive picture of the electronic structure is provided
with the aid of time dependent density functional theory. We have observed
that conformational geometries mainly influence the chemical and electronic
interactions in the presented liquid materials, leading to a direct
association of conformational geometries to the dissolving capacity of the
presented perfluorocarbons with other solvents like water and possibly gases
like oxygen
Presence of factors that activate platelet aggregation in mitral stenotic patients' plasma
BACKGROUND: Although the association between mitral stenosis (MS) and increased coagulation activity is well recognized, it is unclear whether enhanced coagulation remains localized in the left atrium or whether this represents a systemic problem. To assess systemic coagulation parameters and changes in platelet aggregation, we measured fibrinogen levels and performed in vitro platelet function tests in plasma obtained from mitral stenotic patients' and from healthy control subjects' peripheral venous blood. METHODS: Sixteen newly diagnosed patients with rheumatic MS (Group P) and 16 healthy subjects (Group N) were enrolled in the study. Platelet-equalized plasma samples were evaluated to determine in vitro platelet function, using adenosine diphosphate (ADP), collagen and epinephrine in an automated aggregometer. In vitro platelet function tests in group N were performed twice, with and without plasma obtained from group P. RESULTS: There were no significant differences between the groups with respect to demographic variables. Peripheral venous fibrinogen levels in Group P were not significantly different from those in Group N. Adenosine diphosphate, epinephrine and collagen-induced platelet aggregation ratios were significantly higher in Group P than in Group N. When plasma obtained from Group P was added to Group N subjects' platelets, ADP and collagen-induced, but not epinephrine-induced, aggregation ratios were significantly increased compared to baseline levels in Group N. CONCLUSION: Platelet aggregation is increased in patients with MS, while fibrinogen levels remain similar to controls. We conclude that mitral stenotic patients exhibit increased systemic coagulation activity and that plasma extracted from these patients may contain some transferable factors that activate platelet aggregation
The Mediterranean Island Wetlands (MedIsWet) inventory: strengths and shortfalls of the currently available floristic data
MedIsWet (Conservation of the island wetlands of the Mediterranean Basin) is a MAVA funded
project which aims at investigating all seasonal or permanent island wetlands both natural and
artificial, with a minimum extent of 0.1 hectares. More than 16,000 wetlands from almost all
the Mediterranean, including islands from France, Italy, Malta, Croatia, Cyprus, Tunisia,
Turkey, Greece and Spain were mapped. Over 2,500 of them were inventoried in the field and
more than 500 scientific contributions catalogued. In total, more than 35,000 plant occurrences
were uploaded, in a standardised and comparable way, on the national open-source web portals.
These can be related to the recorded threats, uses and other spatially retrievable information.
Here, we show strengths and shortfalls of the already available information about the floristic
records. Although further improvements are needed, we discuss how these data can be used for
research and policy actions and to develop conservation projects
Single left coronary artery with separate origins of proximal and distal right coronary arteries from left anterior descending and circumflex arteries – a previously undescribed coronary circulation
A single left coronary artery with right coronary artery arising from either left main stem (LMS) or left anterior descending artery (LAD) or circumflex artery (Cx) is an extremely rare coronary anomaly. This is the first report of separate origins of proximal and distal RCA from LAD and circumflex arteries respectively in a patient with a single left coronary artery. This 57 year old patient presented with unstable angina and severe stenotic disease of LAD and Cx arteries and underwent urgent successful quadruple coronary artery bypass grafting. The anomalies of right coronary artery in terms of their origin, number and distribution are reviewed
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