Sürdürülebilir Kalkınma Amaçları
Yazarlar
- Bektaş, Osman(2)
- Eyüboǧlu, Yener(2)
- Kaygusuz, Abdullah(2)
- Maden, Nafiz(2)
- Acarbay, Saba Mukaddes(1)
- Akbas, Turkay(1)
- Akçar, Naki(1)
- Aliyazicioglu, Yuksel(1)
- Alpdogan, Ozcan(1)
- Aslan, Zafer(1)
- Ata, Adnan(1)
- Avlagi, L. Serap(1)
- Aydemir, Ferhan Demirer(1)
- Aydin, Faruk(1)
- Aydin, Kaniye(1)
- Aydin, Kutlay(1)
- Aydin, Musa(1)
- Aydinçakir, Emre(1)
- Ayvaz, Melekcol(1)
- Balik, Yelda(1)
- Bayram, Bahri(1)
- Bektas, Ersan(1)
- Bektas, Ser Ife Gokbulut(1)
- Bilici, Ozgur(1)
- Bulut, Volkan Numan(1)
- Chen, Bin(1)
- Dal, Hayriye Cankar(1)
- Demir, Selim(1)
- Dokuz, Abdurrahman(1)
- Dural, Bayram(1)
- Duran, Celal(1)
- Erdemir, Mete(1)
- Ergün, Bisar(1)
- Eroǧlu, Hasan(1)
- Eyüpoglu, Selin(1)
- Friedrich, Anke M.(1)
- Gelişli, Kenan(1)
- Gökçe, Onur(1)
- Gönderen, Kamil(1)
- Gücer, Mehmet Ali(1)
Yayınlar
- MakaleAçık Erişim2026Preferences for mechanical ventilation modes among intensivists in Türkiye: a nationwide point-prevalence study
Yildirim, Suleyman; Kilinçözgün, Nurhayat; Alpdogan, Ozcan; Uçar, Huseyin; Taskiran, Imren; Ata, Adnan; Özcan, Ozhan; Öncü, Kivanc; Acarbay, Saba Mukaddes; Güner, Temel
Background/aim: Invasive mechanical ventilation (IMV) is a fundamental intervention for patients with respiratory failure in intensive care units (ICUs). This nationwide, multicenter point-prevalence study aimed to describe current mechanical ventilation mode preferences (conventional, adaptive, and biphasic) in Turkish ICUs and to report associated clinical outcomes descriptively, without assessing causal relationships. Materials and methods: A nationwide, multicenter point-prevalence study was conducted on 17 April 2024 and included adult patients (>= 18 years) who had been receiving IMV for more than 24 h. Data on patient demographics, ventilation mode distribution, ventilatory parameters, and descriptive clinical outcomes on day 28 (weaning status, tracheostomy, and mortality) were recorded without comparative outcome analysis. Results: A total of 426 patients were included. Conventional modes were used in 84.5% of patients, adaptive modes in 10.6%, and biphasic modes in 4.9%. Synchronized intermittent mandatory ventilation (SIMV) was the most commonly used conventional mode. The primary indication for IMV was acute respiratory failure (61%), with pneumonia being the leading cause. Among the 350 orotracheally intubated patients, 25.6% were in the weaning phase on the study day. A total of 59 (16.9%) patients were extubated, 150 (42.9%) underwent tracheostomy, and 64 (18.2%) remained intubated on day 28. Overall, 185 (43.4%) patients died during their ICU stay, 152 (35.7%) remained in the ICU, and 89 (20.9%) were successfully discharged from the ICU. Conclusion: Conventional ventilation modes, particularly SIMV, were more commonly used in Turkish intensive care units (ICUs), whereas adaptive modes were less frequently applied. These patterns may reflect factors such as clinician familiarity, institutional practices, and equipment availability rather than definitive preferences. Although the impact of ventilation modes on clinical outcomes was not comparatively evaluated in this study, the choice of ventilation mode may still influence patient outcomes. Therefore, further prospective and comparative studies are warranted to better elucidate this relationship.
- MakaleAçık Erişim2025Geochronological and isotopic data from the adakitic Dodurga Pluton (Central Pontides, N Turkiye): new insights for the geodynamic evolution of the northern Neotethys
Çimen, Okay; Gücer, Mehmet Ali; Simonetti, Antonio; Karaoglan, Fatih
The Dodurga Pluton is located within the Central Pontides (northern Turkiye), has a SW-NE elongation, and consists of granodiorite and dacite porphyry. Previous studies have suggested that this pluton is Triassic in age, and its whole-rock geochemical systematics is consistent with that from adakitic magmatic occurrences rather than the classic arc granitoid suite. This study reports for the first time in situ/whole-rock radiogenic isotopic (Sr, Nd, and Pb) and mica/amphibole Ar-Ar age data to evaluate better its petrogenetic/geodynamic evolution and the chemical nature of mantle source(s). Unlike previous data, combined new in situ zircon U-Pb yield Late Cretaceous crystallization ages of 84.2 +/- 0.9 Ma and 86.9 +/- 0.9 Ma, and the Ar-Ar age data along with apatite fission track measurements suggest magma cooling extending to 82.3 +/- 0.4 Ma and 85.4 +/- 0.4 Ma, respectively. The apatite fission track (AFT) dating results also reveal that this pluton was buried at a depth of 2.5-3 km following a fast-cooling period during the Late Cretaceous and cooled/exhumed over similar to 2 km during the Middle-Late Miocene (15-10 Ma) in a slow cooling phase. The overall data reported here suggest that the Dodurga Pluton represents melts derived from an enriched/metasomatized mantle source that interacted with lower crustal mafic rocks in an active continental margin as a result of northward subduction of the northern branch of the Neotethys Ocean.
- MakaleAçık Erişim2024Eocene magmatism related to postcollisional extension in the Eastern Pontides (NE Turkiye): 40Ar-39Ar geochronology, geochemistry, and whole-rock Sr-Nd-Pb-Hf isotopes
Aydinçakir, Emre; Yücel, Cem; Kaygusuz, Abdullah; Bilici, Ozgur; Yilmazer, Sinan; Ruffet, Gilles
The mineral chemistry, whole-rock geochemistry, 40 Ar / 39 Ar dating and Sr-Nd-Pb-Hf isotopes of the Eocene Narman (Erzurum) Volcanic rocks in the southeast of the Eastern Pontides Orogenic Belt (EPOB, NE Turkiye) were investigated. The Narman Volcanites consist of basaltic dyke, basaltic lava, and basaltic volcanic breccia facies. Volcanites contain plagioclase (An34-80), 34-80 ), clinopyroxene (Wo38- 38- 47En41-50Fs5-18), En 41-50 Fs 5-18 ), and olivine (Fo 68-90 ) as phenocrystals with magnetite/titanomagnetite microphenocrysts. New 40 Ar- 39 Ar ages suggest that these volcanic rocks erupted between 44.5 +/- 0.1 and 43.4 +/- 0.1 Ma, within the Middle Eocene (Lutetian). Narman Volcanites have calcalkaline character, with medium-high K content. Volcanites are enriched in large ion lithophile elements (LILE) and light rare earth elements (LREE), while they are depleted in terms of high field strength elements (HFSE). Chondrite-normalized rare earth element distributions have concave shape with moderate enrichment (LaN/LuN= N /Lu N = 2.78-7.99), leading to consideration that the magmas forming the volcanics derived from similar sources. Isotopically, the rocks in the Narman Volcanites have low-medium initial 87 Sr/ 86 Sr values (0.70405-0.70485), initial 143 Nd/ 144 Nd values (0.512606-0.512848) and positive Nd i (+0.5 - +5.2). Depleted mantle Nd model ages were T DM1 = 0.29-0.62 Ga and T DM2 =0.43-0.83 Ga. (206Pb/204Pb)i, 206 Pb/ 204 Pb) i , (207Pb/204Pb)i, 207 Pb/ 204 Pb) i , and (208Pb/204Pb)i 208 Pb/ 204 Pb) i values vary in the ranges of 18.246-18.709, 15.578-15.616, and 38.225-38.791, respectively. The initial (176Hf/177Hf)i 176 Hf/ 177 Hf) i ratios for the volcanites are between 0.282770 and 0.283013, while the epsilon Hf values range from +7.6 to +9. All the evidence supports the conclusion that the parental magma for the rocks probably derived from an enriched lithospheric mantle, previously metasomatized by fluids derived from subducted slab during asthenospheric upwelling, due to fragmented asymmetric delamination in a postcollisional extensional tectonic environment.
- MakaleAçık Erişim2023Internal deformation of continental blocks within converging plates: insights from the Ovacik Fault (Anatolia, Turkiye)
Zabci, Cengiz; Sançar, Taylan; Tikhomirov, Dmitry; Ivy-ochs, Susan; Vockenhuber, Christof; Friedrich, Anke M.; Yazici, Muge; Akçar, Naki
The active tectonics of Anatolia is mostly characterized by its westward motion with respect to Eurasia between the Hellenic subduction in the west and Arabia-Eurasia continental collision in the east. Although most of the deformation is suggested to be confined along Anatolias boundary elements, viz. the North and East Anatolian shear zones, recent studies indicate a higher magnitude of internal strain accumulation, especially along the parallel/subparallel strike-slip faults of its central province. We present the first morphochronology-based slip rate estimate for one of these strike-slip structures, the Ovacik Fault, by using cosmogenic 36Cl dating of offset fluvial deposits. At the Kcseler Site (39.3643 degrees N, 39.1688 degrees E), two faulted risers, bounding the alluvial fan with its subplanar surface (NF1/NF1') and the inset terrace tread (NF1/T2), are offset 19-24 and 15-22 m, respectively. The scattered surface ages and variability of 36Cl concentrations in depth profiles suggest strong evidence for inheritance in alluvial fan and terrace deposits; thus, we used modelled depth-profile ages for both surfaces. The modelled ages 8-10 ka for NF1 and 6-8 ka for T2 yield slip-rate estimates 2.4 +0.5/-0.4 mm/a and 2.8 +0.7/-0.7 mm/a, respectively, for the upper-tread reconstruction of the NF1/NF1'and the lower-tread reconstruction of the NF1/T2. Our results together with previous slip-rate estimates for other structures show a significant internal deformation for Anatolia, especially along its subparallel strike-slip faults. These secondary faults slice Anatolia into several pieces giving rise to the formation of the Malatya-Erzincan, Cappadocian, and Central Anatolian slices, where the geometry is strongly controlled by the distribution of the Tethyan accretionary complexes.
- MakaleAçık Erişim2017Synthesis, in vitro DNA interactions, cytotoxicities, antioxidative activities, and topoisomerase inhibition potentials of Mn(II), Co(II), Ni(II), Cu(II), and Zn(II) complexes with azo-oxime ligands
Ayvaz, Melekcol; Turan, Ibrahim; Dural, Bayram; Demir, Selim; Karaoglu, Kaan; Aliyazicioglu, Yuksel; Serbest, Kerim
Mn(II), Co(II), Ni(II), Cu(II), and Zn(II) transition metal complexes of 2-hydroxy-5-[(E)-(4-phenyl) diazenyl] benzaldehyde oxime and 2-hydroxy-5-[(E)-(4-nitrophenyl) diazenyl] benzaldehyde oxime ligands were synthesized and characterized through NMR, IR, ESI mass, and UV analysis. DNA binding abilities of the complexes were revealed using a UV-Vis spectrophotometer with the absorption titration and competitive binding techniques. Hydrolytic and oxidative DNA cleavage activities under different conditions were also proved. Topoisomerase I inhibition efficiencies and in vitro free radical scavenging activities of all complexes were examined. Finally, the selective cytotoxic potentials of all complexes were evaluated in human colon cancer, normal colon, and fibroblast cell lines using the water-soluble tetrazolium salt (WST-1) assay. The complexes had the ability to intercalate into stacked base pairs of DNA and topoisomerase I activity was reasonably inhibited in their presence in 0.4 mM concentrations. The abilities for scavenging of DPPH and hydroxyl radicals were found to be higher than those of known standard antioxidants (ascorbic acid, butylated hydroxyanisole, and mannitol). The results obtained from the cytotoxicity experiments are especially promising for further research, which must be carried out for the evaluation of the studied complexes as anticancer drugs.
- MakaleAçık Erişim2017Accumulation of phenolics in natural and micropropagated plantlets of Thymus pseudopulegioides Klokov & Des.-Shost. with their antioxidant potentials
Günaydin, Mustafa; Laghari, Abdul Hafeez; Bektas, Ersan; Sökmen, Munevver; Sökmen, Atalay
Thymus pseudopulegioides plantlets were propagated in vitro via direct organogenesis by using Murashige and Skoog (MS) media containing kinetin, thidiazuron, and 6-benzyladenine (BA) individually. Methanol extracts obtained both from plantlets and wild plants were analyzed for their total phenolics and flavonoid contents, then quantified by HPLC. The highest total phenolic (8.83 mg/g as gallic acid equivalent) and total flavonoid (0.92 mg/mL as rutin equivalent) values were from the MS media supplemented with 1.0 mg/L kinetin and 0.5 mg/L BA, respectively. The plantlets grown in those media also showed remarkable antioxidant activities with an IC50 value of 4.77 mu g/mL in DPPH and 100% inhibition in beta-carotene assays, respectively. HPLC analysis proved the production of protocatechuic, caffeic, vanillic, rosmarinic, ferulic, and o-coumaric acids and rutin. Rosmarinic acid production was predominant in natural samples (115.2 mg/100 g dry weight), while the aforesaid phenolic acids were prevalent in plantlets grown on MS media supplemented with KIN or BA at various concentrations. Rutin production was the highest (50.74 mg/100 g dry weight) in the plantlets grown on MS medium containing kinetin (1.0 mg/L). As an economically important chemical, rosmarinic acid was selected as the target chemical and a novel method was introduced to achieve its selective isolation.
- MakaleAçık Erişim2013Antioxidant effect of rosehip seed powder in raw and cooked meatballs during refrigerated storage
Ilyasoǧlu, Huri
The aim of this study was to learn the usage ability of rosehip seed powder (RSP) as an antioxidant agent to prevent lipid oxidation in raw and cooked meatballs during refrigerated storage. For this purpose, 4 different formulations (without RSP and with 1%, 2%, and 4% RSP) were prepared. Thiobarbituric acid reactive substances (TBARS) values of the raw and cooked meatballs were determined at 0, 3, 6, 9, and 12 days of storage. Both the raw and the cooked meatballs containing 2% RSP had lower TBARS values at the end of storage compared to the control meatballs. Moreover, the difference in sensorial properties between the cooked control sample and cooked RSP-added test samples was not significant. These results indicated that RSP may be utilized as a natural antioxidant in cooked meatballs.
- MakaleAçık Erişim2013Simulation of a large electric distribution system having intensive harmonics in the industrial zone of Konya
Eroǧlu, Hasan; Aydin, Musa
In this study, measurements were taken at difierent points of a sample distribution system in order to analyze the levels of harmonics that appear as a day-to-day increasing problem in electrical distribution systems. According to the measurement values, the dominant harmonics have been determined and an electrical model of the system has been prepared using the SimPowerSystems toolbox from MATLAB and Simulink. The accuracy of the electrical model has been verified by the measurement and simulation values. In addition, the transformer connection types' and impedances' simulations have been presented to understand and solve the harmonic problems in electrical distribution systems. With the help of this study, advanced analysis can be performed in the electrical distribution system for power quality analyses and this study can be a background for similar kinds of simulation studies.
- MakaleAçık Erişim2012Optimization of a new cloud point extraction procedure for the selective determination of trace amounts of total iron in some environmental samples
Duran, Celal; Özdeş, Duygu; Çelenk Kaya, Elif; Kantekin, Halit; Bulut, Volkan Numan; Tüfekçi, Mehmet
A new, simple, and rapid cloud point extraction (CPE) procedure system, combined with flame atomic absorption spectrometry (FAAS), was developed for selective separation, preconcentration, and determination of trace amounts of total iron in some environmental samples. The complexing agent, N,N-(2,2 - (ethane-1,2-diylbis(oxy))bis(ethane-2,1-diyl))bis(2-chloroacetamide) (EDBOCA), is selective at pH 5.0 for only Fe(II) and Fe(III) ions in the presence of Cu(II), Pb(II), Cd(II), Mn(II), Co(II), Cr(III), Cr(VI), Ni(II), Zn(II), Al(III), Mo(VI), Pd(II), Pt(IV), Au(III), and V(V) ions. The procedure is based on the complexation of Fe(III) ions with EDBOCA reagent in the presence of Triton X-114 (TX-114) as a non-ionic surfactant. The optimum conditions for the CPE of Fe(III) ions were investigated with respect to several experimental parameters such as pH of the solution, TX-114 and EDBOCA concentrations, incubation time and temperature, and centrifugation rate and time. The detection limit for Fe(III) ions based on the 3 times the standard deviation of the blanks (N:10) was found to be 1.22 μg L ?1 , while the relative standard deviation (RSD) was 4.2%. Environment Canada TM-25.3 and CRM-SA-C Sandy Soil C, as certified reference materials, were used, and spike tests were applied to validate the method. The method was applied to some real environmental samples to evaluate their total iron levels.
- MakaleAçık Erişim2011First Report of a Trilobite in the Carboniferous of Eastern Pontides, NE Turkey
Kandemir, Raif; Lerosey-Aubril, Rudy
The pre-Mesozoic basement of the Eastern Pontides consists of a Permo-Carboniferous sedimentary sequence including the Catalcesme and Hardisi formations. The Catalcesme Formation has yielded rich assemblages of fusulinids, corals, gastropods, brachiopods, bryozoans, algae, conodonts and plants. Hitherto trilobites were unknown from this formation; here we report the discovery of a pygidium from a dark grey limestone bed near the top. Trilobites are a minor component of benthic marine communities during the Late Pennsylvanian, and to our knowledge, the discovery of this pygidium constitutes the first report of their occurrence in deposits of this age in Turkey. The morphological characteristics of the specimen, especially the number of axial rings and pleural ribs and the well-defined border (Owens 1983), suggest that it probably belongs to an undescribed species of Ditomopyge Newell, 1931 (Ditomopyginae). It also exhibits a distortion of the posterior part of the axis, and a shortening (right side) or a fusion (left side) of some pleural ribs, which is tentatively interpreted as repaired injuries or the results of a developmental dysfunction.
- MakaleAçık Erişim2009U-Pb SHRIMP zircon ages, geochemical and Sr-Nd isotopic compositions of the late cretaceous I-type Sariosman pluton, Eastern Pontides, NE Turkey
Kaygusuz, Abdullah; Chen, Bin; Aslan, Zafer; Siebel, Wolfgang; Şen, Cüneyt
The petrogenesis and U-Pb SHRIMP zircon ages of the Late Cretaceous Sariosman pluton in the Eastern Pontides is investigated by means of whole-rock Sr-Nd isotope data with field, petrographic and whole-rock geochemical studies. The bulk of the I-type Sariosman pluton consists of biotite-hornblende monzogranite, with minor quantities of porphyritic hornblende-biotite monzogranite. The biotite-hornblende monzogranite contains a number of mafic microgranular enclaves (MMEs) of quartz monzodiorite composition. U-Pb zircon sensitive high-resolution ion microprobe dating (SHRIMP) dates the magma emplacement age of the biotite-hornblende monzogranite at 82.7±1.5 Ma. The rocks of the pluton show high-K calc-alkaline, metaluminous to slightly peraluminous characteristics, and are enriched in large ion lithophile elements (LILE) and light rare earth elements (LREE) relative to high field strength elements (HFSE), thus displaying features of arc-related granitoids. Chondrite-normalised rare earth-element (REE) patterns have concave upward shapes (Lacn/Lucn= 10.1-17.4) with pronounced negative Eu anomalies (Eu/Eu*= 0.61-0.80). Initial εNd values vary between -3.0 and -4.1 and initial 87Sr/86Sr values between 0.7062 and 0.707. The MMEs are characterised by higher Mg-numbers (27-29) and lower values of both SiO2 (56-58 wt%) and aluminium saturation index (0.9-1.0), compared to the monzogranites. Fractionation of plagioclase, hornblende and Fe-Ti oxides played an important role in the evolution of the Sariosman pluton. The crystallisation temperatures of the melts ranged from 700 to 800 °C and a relatively shallow intrusion depth (~2 to 7 km) is estimated from the Al-in-hornblende geobarometry. The geochemical and isotopic compositions of the Sariosman pluton suggest an origin through dehydration melting of mafic lower crustal source rocks.
- MakaleAçık Erişim2009Two-and-three-dimensional crustal thickness of the Eastern Pontides (NE Turkey)
Maden, Nafiz; Gelişli, Kenan; Eyüboǧlu, Yener; Bektaş, Osman
The Eastern Pontide orogenic belt is divided into three subzones (northern, southern and axial zones) based on present lithologies and facies associations. NE-SW-, NW-SE- and E-W-trending fault systems, which play an important role in palaeotectonics and neotectonics of the Eastern Pontides separate these zones. Three different methods were used to estimate the Moho depth from observed gravity value, namely (i) empirical relationship between Moho depth and Bouguer anomaly; (ii) spectral analysis of the radial wave number and; (iii) by the gravity inversion method. Power spectrum, a statistical approach, is a widely used technique to determine the depth of geological sources successfully. The empirical linear relations between the Bouguer anomalies and seismically determined crustal thicknesses have been used to compute depths to the Conrad and Moho discontinuities, which are consistent with the average depths obtained from the power spectrum method. The crustal structure was also determined from the inversion of a Bouguer anomaly profile along longitude 39°. Gravity inversion results are consistent with those obtained from the empirical relations and power spectrum methods. We calculated the maximum crustal thickness of 43.8 km in the studied region by using the gravity inversion method, which also showed that crustal thickness increases from north to south.
- MakaleAçık Erişim2009Compositional variations, zoning types and petrogenetic implications of low-pressure clinopyroxenes in the neogene alkaline volcanic rocks of northeastern Turkey
Aydin, Faruk; Karsli, Orhan; Sadiklar, M. Burhan
Clinopyroxene phenocrysts and microphenocrysts in different series of the Neogene alkaline volcanic rocks from the eastern Pontides (NE Turkey) record various stages in the crystallization conditions and evolution history of the alkaline melt as well as its origin. Crystal chemical studies reveal that the clinopyroxenes in each rock series show strong textural and compositional similarities, which all reflect a common petrogenetic affinity. They have relatively high Mg-numbers (0.68-0.95), variable Al2O3 (1.3-9.6 wt%), low TiO2 (<2.7 wt%) and Na2O (<0.9 wt%) contents and low Al[6]/Al[4] ratios (mostly <0.25), suggesting relatively low-pressure crystallization conditions of the magma in the storage region. The pressures calculated for the clinopyroxenes in each series are nearly similar and vary in the range of 2.4-4.6 ± 0.9 kbars, which approximately corresponds to a crystallization depth of 7-14 ± 3 km. The analyses of the compositional trends of the clinopyroxenes indicate the following types of zoning: (i) oscillatory and sectorial zoning related to melt crystallization (i.e. rapid cooling and crystallization), (ii) oscillatory, reverse zoning related to the different crystallization paths under a variable fluid regime, (iii) normal zoning related to the differentiation and fractional crystallization of the magma. Based on the primitive mantle- and chondrite-normalized trace and rare earth element patterns, all clinopyroxenes have high abundances of incompatible elements (i.e. La, Ce) with negative high field strength element anomalies (i.e. Zr, Ti) and low Nb/Y (0.1-0.2), Th/Y (< 0.1) and Rb/Y (< 0.03) ratios, suggesting derivation from a similar source. Obtained textural and mineral chemical data, as well as whole-rock compositions, thus suggest that the clinopyroxenes may have started to crystallize from alkaline basaltic magma derived from a homogeneous lithospheric mantle enriched by an earlier subduction event. After this process, the alkaline magma, from which early clinopyroxenes crystallized, underwent a relatively low-pressure fractional crystallization process. This was in closed magma chambers at different levels of the crust (or within a volcanic conduit system devoid of interaction processes), shown by variations in the different crystallization paths and in the fluid regime of the melt during differentiation and ascent of the magma, in a post-collisional extensional tectonic regime which affected the eastern Pontides during the Neogene.
- MakaleYalnız künye2007Different modes of stress transfer in a strike-slip fault zone: An example from the North Anatolian Fault System in Turkey
Bektaş, Osman; Eyüboǧlu, Yener; Maden, Nafiz
The dextral North Anatolian Fault System (NAFS) extends for well over 1000 km from the compressive tectonic domain of eastern Anatolia into the broad and diverse tectonic domain of the western Anatolian, Marmara and Aegean regions. These different tectonic regimes are characterized by a narrow deformation zone in the east and a much broader deformation zone with multiple sub-parallel fault zones in the west. The spatial and temporal distribution of large historical and modern earthquakes (Mw>5) shows two distinctive macro-seismic zones in the eastern and western parts of the NAFS. The eastern macro-seismic zone, between the towns of Erzincan and Bolu, has produced a successive linear earthquake series parallel to the fault system over the last 500 years, suggesting that stress transfer along the fault occurred in a manner of 'Static Coulomb failure stress changes' through the entire elastic crust. In contrast, the western macro-seismic zone of the NAFS, in the Marmara region, has produced successive earthquake pairs on the parallel faults, implying 'dynamic stress changes', involving large-scale flow in the aseismic lower crust and the mantle.
- MakaleYalnız künye2006Effects of feeding acidified milk replacer on the growth, health and behavioural characteristics of holstein Friesian calves
Yanar, Mete; Güler, Olcay; Bayram, Bahri; Metin, Jale
The objective of this study was to compare the performances of calves fed acidified milk replacer (AMR) or sweet (regular) milk replacer (SMR) at 8% of birth weight. Twenty- one calves (10 males, 11 females) were offered replacers reconstituted to 12% of dry matter over 5 weeks. In the group fed AMR, daily body weight gains of calves at the different stages of growth were comparable to those for calves fed SMR. In the preweaning period, calves offered AMR had similar dry matter intakes from starter, milk replacer and dry hay as well as total intake as those fed SMR. In the postweaning phase, total dry matter intakes of calves offered AMR and SMR were not statistically different. The overall feed efficiency ratios of AMR- fed calves were better (P < 0.05) than those of SMR- fed calves. Calf faecal consistency score (P < 0.05) and percent days with scours (P < 0.01) of calves offered AMR were significantly lower than those fed SMR for days 4 to 17. AMR-fed calves needed a longer time (P < 0.01) to consume the daily amount of replacer than SMR- fed calves. The calves fed AMR also took a significantly (P < 0.05) greater number of days to learn to drink milk replacer from an open pail without help than calves consuming SMR. In conclusion, it is suggested that the growth performance and feed efficiency characteristics of calves reared under the new feeding system with AMR were not adversely affected, but the incidence of scours of the young calves was dramatically reduced.
- MakaleYalnız künye2006Geochemical constraints on the provenance, mineral sorting and subaerial weathering of Lower Jurassic and Upper Cretaceous clastic rocks of the eastern Pontides, Yusufeli (Artvin), NE Turkey
Dokuz, Abdurrahman; Tanyolu, Erkan
An integrated petrographic and geochemical study of the shales and sandstones of Early Jurassic and Late Cretaceous age in the Yusufeli area (Turkey) was carried out to obtain more information on their provenance, sedimentological history and tectonic setting, as well as to evaluate the influence of weathering, hydraulic sorting and recycling processes upon source-rock signature. Depending on their matrix and mineralogical content the Lower Jurassic sandstones are identified as arkosic arenite and wacke, while the Upper Cretaceous sandstones are defined as lithic arenite and wacke. Elemental ratios such as La/Sc, Cr /Ni, Co/Th, Th/Sc and Cr/Th indicate a mafic source for the marjority of each of the sandstone sequences. However, in several samples, high Th/Sc and low Cr/Th ratios suggest a contribution from a felsic source. Using element-ratio diagrams, all of the samples plot along a curve consistent with a two-component mixing model, consisting of a dominant mafic and a subordinate felsic source. The relatively low Cr/Ni ratios provide no support for significant amounts of ultramafic lithologies in the source area. The lower trace-element contents of the studied sandstones in relation to post-Archean Australian shales (PAAS), which are representative of the composition of the upper continental crust, indicate that recycling processes in their source areas were probably less intense than those of the PAAS. The more LREE-depleted patterns of the shales relative to sandstones likely do not reflect changes in source-area composition but, rather, variations in mineral sorting, chemical weathering and/or sediment recycling. Chemical index of alteration (CIA) indices observed in the Lower Jurassic and Upper Cretaceous sediments (average of 53 & 46, respectively) suggest that their source area underwent moderate degrees of chemical weathering processes. However, an upward increase in the values of the CIA indices in the Lower Jurassic profiles may indicate that the source area gradually underwent more intense chemical weathering, possibly due to climatic and/or tectonic variations. On the other hand, an upward decrease in the CIA indices of the Upper Cretaceous profiles generally demonstrate that the sediments were derived from a relatively less-weathered source terrain, reflecting an increased erosion rate likely due to increasing tectonic activity. The compositional immaturity of the analysed sandstone samples is typical of subduction-related environments, and their SiO2/Al2O3 and K2O/Na2O ratios and Co, Sc, Th and Zr contents reflect their oceanic and continental-arc settings.
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