386 research outputs found
Patch Burning: Implications on Water Erosion and Soil Properties
Patch burning can be a potential management tool to create grassland heterogeneity and enhance forage productivity and plant biodiversity, but its impacts on soil and environment have not been widely documented. In summer 2013, we studied the effect of time after patch burning (4 mo after burning [recently burned patches], 16 mo after burning [older burned patches], and unburned patches [control]) on vegetative cover, water erosion, and soil properties on a patch-burn experiment established in 2011 on a Yutan silty clay loam near Mead, NE. The recently burned patches had 29 ± 8.0% (mean ± SD) more bare ground, 21 ± 1.4% less canopy cover, and 40 ± 11% less litter cover than older burned and unburned patches. Bare ground and canopy cover did not differ between the older burned and unburned patches, indicating that vegetation recovered. Runoff depth from the older burned and recently burned patches was 2.8 times (19.6 ± 4.1 vs. 7.1 ± 3.0 mm [mean ± SD]) greater than the unburned patches. The recently burned patches had 4.5 times greater sediment loss (293 ± 89 vs. 65 ± 56 g m-2) and 3.8 times greater sediment-associated organic C loss (9.2 ± 2.0 vs. 2.4 ± 1.9 g m-2) than the older burned and unburned patches. The recently burned patches had increased daytime soil temperature but no differences in soil compaction and structural properties, dissolved nutrients, soil C, and total N concentration relative to older burned and unburned patches. Overall, recently burned patches can have reduced canopy and litter cover and increased water erosion, but soil properties may not differ from older burn or unburned patches under the conditions of this study
Late Palaeozoic extensional volcanism along the northern margin of Gondwana in southern Turkey: implications for Palaeotethyan development
The Late Palaeozoic-Early Mesozoic Tethyan development of the Eastern Mediterranean region remains debatable, especially in Turkey, where alternative northward and southward subduction hypotheses are proposed. Relevant to this debate, new whole-rock geochemical data are provided here for early Carboniferous (Late Tournaisian-Late Visean; c. 340-350 Ma) tuffaceous sedimentary rocks within the cataloturan thrust sheet (Aladag nappe), eastern Taurides. The tuffs accumulated from evolved alkaline volcanism, variably mixed with terrigenous and radiolarian-rich sediments. In addition, Late Palaeozoic meta-volcanic rocks, c. 150 km farther NE, within the Binboga (= Malatya) metamorphics (a low-grade high-pressure unit), are indicative of a within-plate setting. An impersistent geochemical subduction signature in these volcanics may represent an inherited, rather than contemporaneous, subduction influence, mainly because of the absence of a continental margin arc or of arc-derived tuff. Both the Binboga metamorphics and the cataloturan thrust sheet (Aladag nappe) restore generally to the north of the relatively autochthonous Tauride carbonate platform (Geyik Dag), within the carbonate platform bordering north-Gondwana. The cataloturan thrust sheet is interpreted, specifically, as a c. E-W, deep-water, volcanically active rift that progressively infilled. Regional geological evidence suggests that melange units (Konya Complex, Afyon zone), Teke Dere unit, Lycian nappes), and Chios-Karaburun melange, E Aegean) accreted to the north-Gondwana continental margin during the late Carboniferous; this was coupled with localised calc-alkaline granitic magmatism (Afyon zone of Anatolide crustal block). We propose an interpretation in which Late Devonian-Carboniferous alkaline intra-plate volcanism relates to extension/rifting along the north-Gondwana margin. In contrast, the melange accretion and granitic magmatism could relate to short-lived late Carboniferous southward subduction that accompanied the diachronous closure of Palaeotethys
Testing alternative tectonic models for the Permian-Pleistocene tectonic development of the Kyrenia Range, N Cyprus: Implications for E Mediterranean Tethyan palaeogeography
Three published alternative tectonic models of the Permian-Pleistocene development of the Kyrenia Range, N Cyprus are tested, supported by new field, geochemical and micropalaeontological evidence: 1. The Kyrenia Range represents the northern continental margin of the S Neotethys, close to its present relative position. The range initiated as a Permian-Cretaceous rift/passive margin, switching to a N-facing active margin during Late Cretaceous-Neogene; 2. The Range was located along the N African continental margin until the Neogene when northward subduction transferred it to the southern margin of the Eurasian plate; 3. The Range is a far-travelled allochthon that was emplaced to near its present position, probably during the Eocene.In the light of regional comparisons, especially with southern Turkey, the combined evidence mainly supports tectonic model 1. Sedimentary and palaeontological data show that the restored stratigraphy of the Kyrenia Range indicates Late Permian initial rifting and Early-Middle Triassic advanced rifting, followed by Jurassic-Early Cretaceous passive margin subsidence. Small exposures of ophiolite-related melange located between the Mesozoic carbonate platform and the overlying latest Cretaceous-Palaeogene deep-water volcanic-sedimentary succession include evidence of HP/LT metamorphism, pointing to Late Cretaceous subduction. MORB/boninites, diabase-gabbro and extensive harzburgitic serpentinite originated as a SSZ ophiolite, together with a possible high-grade metamorphic sole (garnet amphibolite) and an accretionary prism (E-MORB/OIB; metachert). Microfossil evidence indicates exhumation of the melange and the underlying platform prior to Late Maastrichtian. A mass-transport complex formed within a compression-related foredeep during the Middle Eocene. Associated southward thrusting and folding culminated in emergence and subaerial erosion, generating a major unconformity, that was followed by subaerial and then marine deltaic deposits (Late Eocene-Oligocene). Following major Late Miocene southward thrusting, uplift of the Kyrenia Range took place during the Pleistocene, related to collision of the leading edge of the North African plate (Eratosthenes Seamount) with the Eurasian (Anatolian) plate
Temperature dependence of electrical properties in In/Cu2ZnSnTe4/Si/Ag diodes
WOS: 000458625200001Cu2ZnSnTe4 (CZTTe) thin films with In metal contact were deposited by thermal evaporation on monocrystalline n-type Si wafers with Ag ohmic contact to investigate the device characteristics of an In/CZTTe/Si/Ag diode. The variation in electrical characteristics of the diode was analysed by carrying out current-voltage (I-V) measurements in the temperature range of 220-360 K. The forward bias I-V behaviour was modelled according to the thermionic emission (TE) theory to obtain main diode parameters. In addition, the experimental data were detailed by taking into account the presence of an interfacial layer and possible dominant current transport mechanisms were studied under analysis of ideality factor, n. Strong effects of temperature were observed on zero-bias barrier height (Phi(B0)) and n values due to barrier height inhomogeneity at the interface. The anomaly observed in the analysis of TE was modelled by Gaussian distribution (GD) of barrier heights with 0.844 eV mean barrier height and 0.132 V standard deviation. According to the Tung's theoretical approach, a linear correlation between Phi(B0) and n cannot be satisfied, and thus the modified Richardson plot was used to determine Richardson constant (A*). As a result, A* was calculated approximately as 120.6 A cm(-2) K-2 very close to the theoretical value for n-Si. In addition, the effects of series resistance (R-s) by estimating from Cheng's function and density of surface states (N-ss) by taking the bias dependence of effective barrier height, were discussed
Investigation of Parameters Affecting Axial Load in an End Suction Centrifugal Pump by Numerical Analysis
The total force produced in the axial direction on a pump is called axial load and is caused by the pressure difference between the front and rear of the impeller and the hydrostatic force in the suction direction. In a centrifugal pump, 3D computer-aided analysis programs are used to design and reduce R&D and manufacturing costs. In this study, parameters affecting axial load of the centrifugal pump with a single suction and closed impeller were investigated by using the Computational Fluid Dynamics (CFD) method. In this context, the flow rate and the some physical properties such as the back gap of the impeller, wear ring and balancing holes, of the centrifugal pump were investigated to determine how much affected the axial load. The results showed that the wear ring and the balancing holes give rise to effective results on the axial load, while the back gap of the impeller does not affect the large extent. With the design changes made with these parameterizations, the axial force was reduced by up to 60%, whereas the efficiency was decreased by 5%. The loss of efficiency due to this decrease in axial force is negligible. However, higher efficiency values were also found at a different point from the working point where the axial load is lowest
Anthropometric measurements of the orbita and gender prediction with three-dimensional computed tomography images
Background: The aim of the study was to investigate the orbital anthropometric variations in the normal population using three-dimensional computed tomography (3D-CT) images and to define the effects of age and gender on orbital anthropometry.Materials and methods: Three-dimensional orbita CT of 280 patients, obtained for various reasons, were retrospectively evaluated in 772-bed referral and tertiary-care hospital between April 2011 and June 2012. Using 3D images, orbital width, height, biorbital-interorbital diameter and orbital index were measured. Measurements were obtained comparing right and left sides and male to female. The relation of the results with age and gender was analysed.Results: Right orbit was found to be wider than left (p < 0.0001). Male patients had wider (p < 0.0001) and higher (p = 0.0001) orbits. Right orbital index was found to be smaller than the left one (p = 0.005). No differences were found between the genders in terms of right and left orbital indexes (p > 0.05). Biorbital (p < 0.0001) and interorbital (p = 0.01) widths were found to be higher in males. There was no relation between the age change and the parameters defined (p > 0.05).Conclusions: No relation was found between age and orbital measurements. It was concluded that orbital images obtained with 3D-CT may be used as a method for gender evaluation
Diagnostic value of combined serum biomarkers for the evaluation of liver fibrosis in chronic hepatitis C infection: A multicenter, noninterventional, observational study
Background/Aims: The hepatitis C virus (HCV) infection is important cause of chronic hepatitis. Liver biopsy is considered the gold standard for assessment of fibrosis but this procedure is an invasive procedure. We aimed to evaluate the diagnostic efficiency of non-invasive serum biomarkers, separately and in combinations, on liver fibrosis in treatment-naive chronic hepatitis C (CHC) patients. Materials and Methods: Two hundred and sixteen treatment-naive CHC patients were enrolled from 32 locations across Turkey in this open-labelled, non-interventional prospective observational study. FibroTest®, aspartate aminotransferase-to-platelet ratio index(APRI), aspartate aminotransferase and alanine aminotransferase ratio (AAR), fibrosis index based on four factors (FIB-4), Age-platelet(AP) index and Forns index were measured and compared with Metavir scores got from liver biopsies. Results: Data from 182 patients with baseline liver biopsy were suitable for analysis. One hundred and twenty patients (65.9%) had F0-F1 fibrosis and 62 patients (34.1%) had F2-F4 fibrosis. APRI 0.732 area under the curve(AUC) indicated advanced fibrosis with 69% sensitivity and 77% specificity. FIB-4 0.732 AUC and FibroTest 0.715 AUC indicated advanced fibrosis with 69% and 78.4% sensitivity, and 75% and 71.4% specificity, respectively. The combined use of tests also led to an increase in AUC and specificity. Combinations of FibroTest with APRI and/or FIB-4, and FIB-4 with APRI were optimal for the evaluation of liver fibrosis. Conclusion: Fibrotest, FIB-4, APRI, AP index and Forns index exhibit good diagnostic performance for determining liver fibrosis in CHC patients, and the use of at least two tests together will increase their diagnostic value still further. © Copyright 2018 by The Turkish Society of Gastroenterology
Antibiotics resistance of Stenotrophomonas maltophilia strains isolated from various clinical specimens.
Background: A limited number of antibiotics are recommended for the
therapy of Stenotrophomonas maltophilia infections due to therapy
difficulties caused by its numerous mechanisms of resistance.
Objectives: In this study conducted over a period of approximately 5
years we aimed to determine resistance rates of S. maltphilia based on
drug classification recommended by Clinical and Laboratory Standards
Institute. Methods: A total of 118 S. maltphilia strains isolated from
various clinical specimens between January 2006 and June 2012 were
included in the study. BD Phoenixautomated microbiology system (Becton
Dickinson, USA) was utilized for species level identification and
antibiotic susceptibility testing. Results: Sixty seven of S.
maltphilia strains were isolated from tracheal aspirate isolates, 17
from blood, 10 from sputum, 10 from wound and 14 from other clinical
specimens. Levofloxacin was found to be the most effective antibiotic
against S. maltphilia strains with resistance rate of 7.6%. The
resistance rates to other antibiotics were as follows: chloramphenicol
18.2%, trimethoprim-sulfamethoxazole 20.3% and ceftazidime 72%.
Conclusion: The study revealed that S. maltphilia is resistant to many
antibiotics. The treatment of infections caused by S. maltphilia should
be preferred primarily as levofloxacin, chloramphenicol, and TMP-SXT,
respectively
Nanomechanics of individual aerographite tetrapods
R.A., O.L. and K.S. would like to thank the German Research Foundation (DFG) for the financial support under schemes AD 183/17-1 and SFB 986-TP-B1, respectively, and the Graphene FET Flagship. R.M. and D.E. would like to thank for financial support from Latvian Council of Science, no. 549/2012. N.M.P. is supported by the European Research Council (ERC PoC 2015 SILKENE no. 693670) and by the European Commission H2020 under the Graphene Flagship (WP14 ‘Polymer Composites’, no. 696656) and under the FET Proactive (‘Neurofibres’ no. 732344). S.S. acknowledges support from SILKENE
The association of tumor-to-background ratios and SUVmax deviations related to point spread function and time-of-flight F18-FDG-PET/CT reconstruction in colorectal liver metastases
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