363 research outputs found
Ä°zmirâAnkara suture as a Triassic to Cretaceous plate boundary â data from central Anatolia
The Ä°zmirâAnkara suture represents part of the boundary between Laurasia and Gondwana along which a wide Tethyan ocean was subducted. In northwest Turkey, it is associated with distinct oceanic subductionâaccretion complexes of Late Triassic, Jurassic and Late Cretaceous ages. The Late Triassic and Jurassic accretion complexes consist predominantly of basalt with lesser amounts of shale, limestone, chert, Permian (274 Ma zircon UâPb age) metagabbro and serpentinite, which have undergone greenschist facies metamorphism. ArâAr muscovite ages from the phyllites range from 210 Ma down to 145 Ma with a broad southward younging. The Late Cretaceous subductionâaccretion complex, the ophiolitic mĂ©lange, consists of basalt, radiolarian chert, shale and minor amounts of recrystallized limestone, serpentinite and greywacke, showing various degrees of blueschist facies metamorphism and penetrative deformation. ArâAr phengite ages from two blueschist metabasites are ca. 80 Ma (Campanian). The ophiolitic mĂ©lange includes large Jurassic peridotiteâgabbro bodies with plagiogranites with ca. 180 Ma UâPb zircon ages. Geochronological and geological data show that Permian to Cretaceous oceanic lithosphere was subducted north under the Pontides from the Late Triassic to the Late Cretaceous. This period was characterized generally by subductionâaccretion, except in the Early Cretaceous, when subductionâerosion took place. In the Sakarya segment all the subduction accretion complexes, as well as the adjacent continental sequences, are unconformably overlain by Lower Eocene red beds. This, along with the stratigraphy of the Sakarya Zone indicate that the hard collision between the Sakarya Zone and the AnatolideâTauride Block took place in Paleocene
Multiple Orbitoides dâOrbigny lineages in the Maastrichtian? Data from the Central Sakarya Basin (Turkey) and Arabian Platform successions (Southeastern Turkey and Oman)
The standard reconstruction of species of Orbitoides dâOrbigny into a single lineage during the late Santonian to the end of the Maastrichtian is based upon morphometric data from Western Europe. An irreversible increase in the size of the embryonic apparatus, and the formation of a greater number of epi-embryonic chamberlets (EPC) with time, is regarded as the main evolutionary trends used in species discrimination. However, data from Maastrichtian Orbitoides assemblages from Central Turkey and the Arabian Platform margin (Southeastern Turkey and Oman) are not consistent with this record. The Maastrichtian Besni Formation of the Arabian Platform margin in Southeastern Turkey yields invariably biconvex specimens, with small, tri- to quadrilocular embryons and a small number of EPC, comparable to late Campanian Orbitoides medius (dâArchiac). The upper Maastrichtian Taraklı Formation from the Sakarya Basin of Central Turkey contains two distinct, yet closely associated forms of Orbitoides, easily differentiated by both external and internal features. Flat to biconcave specimens possess a small, tri- to quadrilocular embryonic apparatus of Orbitoides medius-type and a small number of EPC, whereas biconvex specimens possess a large, predominantly bilocular embryonic apparatus, and were assigned to Orbitoides ex. interc. gruenbachensis Pappâapiculatus Schlumberger based on morphometry. The flat to biconcave specimens belong to a long overlooked species Orbitoides pamiri Meriç, originally described from the late Maastrichtian of the Tauride Mountains in SW Turkey. This species is herein interpreted to be an offshoot from the main Orbitoides lineage during the Maastrichtian, as are forms that we term Orbitoides âmediusâ, since they recall this species, yet are younger than normal occurrence with the accepted morphometrically defined lineage. The consistent correlation between the external and internal test features in O. pamiri implies that the shape of the test is not an ecophenotypic variation, but appears to be biologically controlled. We, therefore, postulate that more than one lineage of Orbitoides exists during the Maastrichtian, with a lineage that includes O. âmediusâ and O. pamiri displaying retrograde evolutionary features
Crustal Imaging Across the North Anatolian Fault Zone from the Auto-Correlation of Ambient Seismic Noise
Seismic images of active fault zones can be used to examine the structure of faults throughout the crust and upper mantle, and give clues as to whether the associated deformation occurs within a narrow shear zone, or is broadly distributed through the lower crust. Limitations on seismic resolution within the crust, and difficulties imaging shallow structures such as the crust-mantle boundary (Moho), place constraints on the interpretation of seismic images. In this study we retrieve body wave reflections from autocorrelations of ambient seismic noise. The instantaneous phase coherence autocorrelations allow unprecedented ambient noise images of the North Anatolian Fault Zone (NAFZ). Our reflection profiles show a Moho reflected P-wave, and additional structure within the crust and upper mantle. We image a distinct vertical offset of the Moho associated with the northern branch of the NAFZ indicating that deformation related to the fault remains narrow in the upper mantle
Complex conductivity of soils
The complex conductivity of soils remains poorly known despite the growing importance of this method in hydrogeophysics. In order to fill this gap of knowledge, we investigate the complex conductivity of 71 soils samples (including four peat samples) and one clean sand in the frequency range 0.1 Hz to 45 kHz. The soil samples are saturated with six different NaCl brines with conductivities (0.031, 0.53, 1.15, 5.7, 14.7, and 22 S m21, NaCl, 258C) in order to determine their intrinsic formation factor and surface conductivity. This data set is used to test the predictions of the dynamic Stern polarization model of porous media in terms of relationship between the quadrature conductivity and the surface conductivity. We also investigate the relationship between the normalized chargeability (the difference of in-phase conductivity between two frequencies) and the quadrature conductivity at the geometric mean frequency. This data set confirms the relationships between the surface conductivity, the quadrature conductivity, and the normalized chargeability. The normalized chargeability depends linearly on the cation exchange capacity and specific surface area while the chargeability shows no dependence on these parameters. These new data and the dynamic Stern layer polarization model are observed to be mutually consistent. Traditionally, in hydrogeophysics, surface conductivity is neglected in the analysis of resistivity data. The relationships we have developed can be used in field conditions to avoid neglecting surface conductivity in the interpretation of DC resistivity tomograms. We also investigate the effects of temperature and saturation and, here again, the dynamic Stern layer predictions and the experimental observations are mutually consistent
The lysosomal stability as a biomarker for the determination of pollution in aquatic environments
Illite occurrences related to volcanic-hosted hydrothermal mineralization in the biga peninsula, NW Turkey: Implications for the age and origin of fluids
A different approach to investigate the origin of fluids, temperature conditions, age of hydrothermal activity of mineralization in the Biga Peninsula, (Koru, Tesbihdere and Kumarlar) employed mineralogical (illite KĂŒbler index, b cell dimension, polytype) and geochemical (major, trace/REE, O-H stable isotope and Rb/Sr dating) methods. The KĂŒbler Index (KI) values of illites indicate different temperature conditions, such as low temperature (high-grade diagenesis) for Koru deposit, and high temperature (anchizone) for the Tesbihdere and Kumarlar deposits. The textural, mineralogical and geochemical data from illites show that these have potential for estimating the age of hydrothermal activity and fluid characteristics. Both mineralogical (high grade diagenetic to anchizonal KI, 1 M polytype, low d060 values) and geochemical (similar major and trace element composition to host-rocks, low octahedral Mg + Fe contents, oxygen and hydrogen isotope composition) data are compatible with commonly known hydrothermal illites. Stable isotope data of illites are well matched to similar data from fluid inclusions, which indicate mainly magmatic fluids. The Rb/Sr age (22.4 ± 2.3 Ma: latest Oligocene and lowest Miocene) of the illites coincides with plutonic intrusions that are the main instigators of hydrothermal activities related to the extensional tectonic regime in the Biga Peninsula. The mineralogical and geochemical data of illites have some important advantages with respect to the use of fluid inclusions in determining ÎŽD of hydrothermal fluids thereby leading to better understanding ore-forming hydrothermal condition
Functional and quality of life outcomes after partial glossectomy: a multi-institutional longitudinal study of the head and neck research network
Background: While aggressive treatment for oral cancer may optimize survival, decrements in speech and swallowing function and quality of life often result. This exploratory study investigated how patients recover their communicative function, swallowing ability, and quality of life after primary surgery [with or without adjuvant (chemo) radiation therapy] for tongue cancer over the course of the first year post-operation.Methods: Patients treated for oral cancer at three institutions (University of Alberta Hospital, Mount Sinai Beth Israel Medical Center, and Turku University Hospital) were administered patient-reported outcomes assessing speech [Speech Handicap Index (SHI)], swallowing [(M.D. Anderson Dysphagia Inventory (MDADI)] and quality of life [European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Head and Neck Module (EORTC-H&N35)]. Outcome measures were completed pre-operatively and at 1-, 6-, and 12-months post-operatively.Results: One hundred and seventeen patients undergoing partial glossectomy with reconstruction participated in this study. Results indicated no significant differences in swallowing function (MDADI and EORTC-H& N35 subscales) between baseline and 6 months post-surgery and no significant differences in speech function (SHI subscales) between baseline and 1 year post-surgery. Most quality of life domains (EORTC-H& N35 subscales) returned to baseline levels by 1 year post-operation, while difficulties with dry mouth and sticky saliva persisted. A clear time trend of adjuvant (chemo) radiation therapy negatively affecting dry mouth scores over time was identified in this study, while negative independent effects of chemoradiation on MDADI swallowing, and EORTC-H& N35 swallowing, eating, and opening mouth subscales were found.Conclusions: Assessment time influenced patient-reported speech, swallowing, and quality of life outcomes, while treatment (by time) effects were found for only swallowing and quality of life outcomes. Results of the present study will help guide clinical care and will be useful for patient counseling on expected short and long-term functional and quality of life outcomes of surgical and adjuvant treatment for oral cavity cancer
Evaporation kinetics in swollen porous polymeric networks
Ponencia presentada en el Congreso Euromar 2014.Fil: Velasco, Manuel Isaac. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Instituto de FĂsica Enrique Gaviola; Argentina.Fil: Silletta, Emilia Victoria. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Instituto de FĂsica Enrique Gaviola; Argentina.Fil: Monti, Gustavo Alberto. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Instituto de FĂsica Enrique Gaviola; Argentina.Fil: Acosta, Rodolfo HĂ©ctor. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Instituto de FĂsica Enrique Gaviola; Argentina.Fil: Velasco, Manuel Isaac. Universidad Nacional de CĂłrdoba. Facultad de MatemĂĄtica, AstronomĂa y FĂsica; Argentina.Fil: Silletta, Emilia Victoria. Universidad Nacional de CĂłrdoba. Facultad de MatemĂĄtica, AstronomĂa y FĂsica; Argentina.Fil: Monti, Gustavo Alberto. Universidad Nacional de CĂłrdoba. Facultad de MatemĂĄtica, AstronomĂa y FĂsica; Argentina.Fil: Acosta, Rodolfo HĂ©ctor. Universidad Nacional de CĂłrdoba. Facultad de MatemĂĄtica, AstronomĂa y FĂsica; Argentina.Fil: Gomez, Cesar Gerardo. Universidad Nacional de CĂłrdoba. Facultad de Ciencias QuĂmicas. Departamento de QuĂmica OrgĂĄnica; Argentina.Fil: Strumia, Miriam Cristina. Universidad Nacional de CĂłrdoba. Facultad de Ciencias QuĂmicas. Departamento de QuĂmica OrgĂĄnica; Argentina.Fil: Gomez, Cesar Gerardo. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Instituto Multidisciplinario de BiologĂa Vegetal; Argentina.Fil: Gomez, Cesar Gerardo. Universidad Nacional de CĂłrdoba. Instituto Multidisciplinario de BiologĂa Vegetal; Argentina.Fil: Strumia, Miriam Cristina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Instituto Multidisciplinario de BiologĂa Vegetal; Argentina.Fil: Strumia, Miriam Cristina. Universidad Nacional de CĂłrdoba. Instituto Multidisciplinario de BiologĂa Vegetal; Argentina.Polymer matrices with well defined structure and pore sizes are widely used in several areas of chemistry such as catalysis, enzyme immobilization, HPLC, adsorbents or controlled drug release. These polymers have pores in its structure both in the dry and swollen state. Although it is well known that the structures and properties greatly differ between these two states, only few methods provide information about the swollen one, even though most of the applications involve the matrices in this situation. Nuclear Magnetic Resonance (NMR) is a suitable tool for the study of the molecular dynamics of different liquids spatially confined in macro, meso and nanopores, through changes in the relaxation times. In transverse relaxation experiments, either diffusion inside the pore, or relaxation induced by mobility restriction of the liquid near the wall, are additional
sources of relaxation, which are extremely useful in the determination of structural and functional properties.Fil: Velasco, Manuel Isaac. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Instituto de FĂsica Enrique Gaviola; Argentina.Fil: Silletta, Emilia Victoria. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Instituto de FĂsica Enrique Gaviola; Argentina.Fil: Monti, Gustavo Alberto. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Instituto de FĂsica Enrique Gaviola; Argentina.Fil: Acosta, Rodolfo HĂ©ctor. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Instituto de FĂsica Enrique Gaviola; Argentina.Fil: Velasco, Manuel Isaac. Universidad Nacional de CĂłrdoba. Facultad de MatemĂĄtica, AstronomĂa y FĂsica; Argentina.Fil: Silletta, Emilia Victoria. Universidad Nacional de CĂłrdoba. Facultad de MatemĂĄtica, AstronomĂa y FĂsica; Argentina.Fil: Monti, Gustavo Alberto. Universidad Nacional de CĂłrdoba. Facultad de MatemĂĄtica, AstronomĂa y FĂsica; Argentina.Fil: Acosta, Rodolfo HĂ©ctor. Universidad Nacional de CĂłrdoba. Facultad de MatemĂĄtica, AstronomĂa y FĂsica; Argentina.Fil: Gomez, Cesar Gerardo. Universidad Nacional de CĂłrdoba. Facultad de Ciencias QuĂmicas. Departamento de QuĂmica OrgĂĄnica; Argentina.Fil: Strumia, Miriam Cristina. Universidad Nacional de CĂłrdoba. Facultad de Ciencias QuĂmicas. Departamento de QuĂmica OrgĂĄnica; Argentina.Fil: Gomez, Cesar Gerardo. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Instituto Multidisciplinario de BiologĂa Vegetal; Argentina.Fil: Gomez, Cesar Gerardo. Universidad Nacional de CĂłrdoba. Instituto Multidisciplinario de BiologĂa Vegetal; Argentina.Fil: Strumia, Miriam Cristina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Instituto Multidisciplinario de BiologĂa Vegetal; Argentina.Fil: Strumia, Miriam Cristina. Universidad Nacional de CĂłrdoba. Instituto Multidisciplinario de BiologĂa Vegetal; Argentina.FĂsica de los Materiales Condensado
Investigating P- and S-wave velocity structure beneath the Marmara region (Turkey) and the surrounding area from local earthquake tomography
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