115 research outputs found

    Microsatellite loci and peroxidase alleles correlation in somaclonal variation of Eucalyptus microtheca F. Muell

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    The aim of this study was to investigate the correlation between biochemical and molecular markers in Eucalyptus microtheca F. Muell. under in vitro culture. For this mean, twig-derived explants obtainedfrom Eucalyptus microtheca 1-year-old seedling were cultured on modified MS medium, supplemented with different concentrations of NAA, Kin and TDZ. POD (peroxidase) alleles patterns were studied among regenerated plantlets to investigate the effect of TDZ concentration on POD activity. A dimer locus, a tetramer locus and two epigenetic bands were observed. Genome variation among somaclonal plantlets were investigated using microsatellite markers. SSR (Simple Sequence Repeat) markers revealed polymorphism among the studied population. Nonparametric statistical analysis showed significant effect of simple sequence repeats loci on peroxidase alleles. Correlation of two similarity matrix POD and SSRs loci was 0.18 using Mental test. Results showed less stability of dimer locus indifferent concentrations of TDZ compared to tetramer locus. Tetramer alleles showed more correlation to SSRs than that of dimmer ones

    Comparing multi-objective optimization techniques to calibrate a conceptual hydrological model using in situ runoff and daily GRACE data

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    Hydrological models are necessary tools for simulating the water cycle and for understanding changes in water resources. To achieve realistic model simulation results, real-world observations are used to determine model parameters within a ā€œcalibrationā€ procedure. Optimization techniques are usually applied in the model calibration step, which assures a maximum similarity between model outputs and observations. Practical experiences of hydrological model calibration have shown that single-objective approaches might not be adequate to tune different aspects of model simulations. These limitations can be as a result of (i) using observations that do not sufficiently represent the dynamics of the water cycle, and/or (ii) due to restricted efficiency of the applied calibration techniques. To address (i), we assess how adding daily Total Water Storage (dTWS) changes derived from the Gravity Recovery And Climate Experiment (GRACE) as an extra observations, besides the traditionally used runoff data, improves calibration of a simple 4-parameter conceptual hydrological model (GR4J, in French: mod`ele du GĀ“enie Rural `a 4 param`etres Journalier) within the Danube River Basin. As selecting a proper calibration approach (in ii) is a challenging task and might have significant influence on the quality of model simulations, for the first time, four evolutionary optimization techniques, including the Non-dominated Sorting Genetic Algorithm II (NSGA-II), the Multi-objective Particle Swarm Optimization (MPSO), the Pareto Envelope-Based Selection Algorithm II (PESA-II), and the Strength Pareto Evolutionary Algorithm II (SPEA-II) along with the Combined objective function and Genetic Algorithm (CGA) are tested to calibrate the model in (i). A number of quality measures are applied to assess cardinality, accuracy, and diversity of solutions, which include the Number of Pareto Solutions (NPS), Generation Distance (GD), Spacing (SP), and Maximum Spread (MS). Our results indicate that according toMS and SP, NSGA-II performs better than other techniques for calibrating GR4J using GRACE dTWS and in situ runoff data. Considering GD as a measure of efficiency, MPSO is found to be the best technique. CGA is found to be an efficient method, while considering the statistics of the GR4Jā€™s 4 calibrated parameters to rank the optimization techniques. The Nash-Sutcliffe model efficiency coefficient is also used to assess the predictive power of the calibrated hydrological models, for which our results indicate satisfactory performance of the assessed calibration experiments

    Improved gravity anomaly fields from retracked multimission satellite radar altimetry observations over the Persian Gulf and the Caspian Sea

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    Satellite radar altimetry observations are used to derive short wavelength gravity anomaly fields over the Persian Gulf and the Caspian Sea, where in situ and ship-borne gravity measurements have limited spatial coverage. In this study the retracking algorithm ā€˜Extrema Retrackingā€™ (ExtR) was employed to improve sea surface height (SSH) measurements that are highly biased in the study regions due to land contaminations in the footprints of the satellite altimetry observations. ExtR was applied to the waveforms sampled by the five satellite radar altimetry missions: TOPEX/POSEIDON, JASON-1, JASON-2, GFO and ERS-1. Along-track slopes have been estimated from the improved SSH measurements and used in an iterative process to estimate deflections of the vertical, and subsequently, the desired gravity anomalies. The main steps of the gravity anomaly computations involve estimating improved SSH using the ExtR technique, computing deflections of the vertical from interpolated SSHs on a regular grid using a biharmonic spline interpolation and finally estimating gridded gravity anomalies. A removeā€“computeā€“restore algorithm, based on the fast Fourier transform, has been applied to convert deflections of the vertical into gravity anomalies. Finally, spline interpolation has been used to estimate regular gravity anomaly grids over the two study regions.Results were evaluated by comparing the estimated altimetry-derived gravity anomalies (with and without implementing the ExtR algorithm) with ship-borne free air gravity anomaly observations, and free air gravity anomalies from the Earth Gravitational Model 2008 (EGM2008). The comparison indicates a range of 3ā€“5 mGal in the residuals, which were computed by taking the differences between the retracked altimetry-derived gravity anomaly and the ship-borne data. The comparison of retracked data with ship-borne data indicates a range in the root-mean-square-error (RMSE) between approximately 1.8 and 4.4 mGal and a bias between 0.4062 and 2.1413 mGal over different areas. Also a maximum RMSE of 4.4069 mGal, with a mean value of 0.7615 mGal was obtained in the residuals. An average improvement of 5.2746 mGal in the RMSE of the altimetry-derived gravity anomalies corresponding to 89.9ā€‰perā€‰cent was obtained after applying the ExtR post-processing

    Comparisons of atmospheric mass variations derived from ECMWF reanalysis and operational fields, over 2003 to 2011

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    There are two spurious jumps in the atmospheric part of the Gravity Recovery and Climate Experiment-Atmosphere and Ocean De-aliasing level 1B (GRACE-AOD1B) products, which occurred in January-February of the years 2006 and 2010, as a result of the vertical level and horizontal resolution changes in the ECMWFop (European Centre for Medium-Range Weather Forecasts operational analysis). These jumps cause a systematic error in the estimation of mass changes from GRACE time-variable level 2 products, since GRACE-AOD1B mass variations are removed during the computation of GRACE level 2. In this short note, the potential impact of using an improved set of 6-hourly atmospheric de-aliasing products on the computations of linear trends as well as the amplitude of annual and semi-annual mass changes from GRACE is assessed. These improvements result from 1) employing a modified 3D integration approach (ITG3D), and 2) using long-term consistent atmospheric fields from the ECMWF reanalysis (ERA-Interim). The monthly averages of the new ITG3D-ERA-Interim de-aliasing products are then compared to the atmospheric part of GRACE-AOD1B, covering January 2003 to December 2010. These comparisons include the 33 world largest river basins along with Greenland and Antarctica ice sheets. The results indicate a considerable difference in total atmospheric mass derived from the two products over some of the mentioned regions. We suggest that future GRACE studies consider these through updating uncertainty budgets or by applying corrections to estimated trends and amplitudes/phases

    Exploring hydro-meteorological drought patterns over the Greater Horn of Africa (1979-2014) using remote sensing and reanalysis products

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    Spatio-temporal patterns of hydrological droughts over the Greater Horn of Africa (GHA) are explored based on total water storage (TWS) changes derived from time-variable gravity field solutions of Gravity Recovery And Climate Experiment (GRACE, 2002-2014), together with those simulated by Modern Retrospective Analysis for Research Application (MERRA, 1980-2014). These hydrological extremes are then related to meteorological drought events estimated from observed monthly precipitation products of Global Precipitation Climatology Center (GPCC, 1979-2010) and Tropical Rainfall Measuring Mission (TRMM, 1998-2014). The major focus of this contribution lies on the application of spatial Independent Component Analysis (sICA) to extract distinguished regions with similar rainfall and TWS with similar overall trend and seasonality. Rainfall and TWS are used to estimate Standard Precipitation Indices (SPIs) and Total Storage Deficit Indices (TSDIs), respectively that are employed to characterize frequency and intensity of hydro-meteorological droughts over GHA. Significant positive (negative) changes in monthly rainfall over Ethiopia (Sudan) between 2002 and 2010 leading to a significant increase in TWS over the central GHA region were noted in both MERRA and GRACE TWS (2002-2014). However, these trends were completely reversed in the long-term (1980-2010) records of rainfall (GPCC) and TWS (MERRA). The four independent hydrological sub-regions extracted based on the sICA (i.e., Lake Victoria Basin, Ethiopia-Sudanese border, South Sudan, and Tanzania) indicated fairly distinct temporal patterns that matched reasonably well between precipitation and TWS changes. While meteorological droughts were found to be consistent with most previous studies in all sub-regions, their impacts are clearly observed in the TWS changes resulting in multiple years of extreme hydrological droughts. Correlations between SPI and TSDI were found to be significant over Lake Victoria Basin, South Sudan, and Tanzania. The low correlations between SPI and TSDI over Ethiopia are likely related to inconsistency between TWS and precipitation signals. Further, we found that hydrological droughts in these regions were significantly associated with Indian Ocean Dipole (IOD) events while El NiƱo Southern Oscillation (ENSO) plays a secondary role

    Analysis of allelic variation in HMW-Glu-1 gene blocks in Iranian wheat cultivars using ALP molecular marker

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    In order to study the allelic variation of Glu-1 gene (High molecular weight glutenin), 100 Iranian wheat cultivars including imported and domestic genotypes were analyzed using ALP-PCR technique. Four specific primer pairs were used based on the genetic loci of Glu-A1, Glu-B1, and Glu-D1 to perform the chain polymerase reactions. PCR reaction products were resolved on 2% agarose gel. Since allele ā€œaā€ had the largest relative frequency (0.707), two alleles (a 344bp; b 362bp) were identified by P1-P2 primer for Glu-A1 locus. Three alleles (a 800bp; b 500bp; c 300bp) were detected for Glu-B1 locus by P5-P6 primer, and allele ā€œbā€ was assumed as the highest relative frequency (0.618). Two primer pairs were applied for Glu-D1 locus. Ultimately, four alleles were identified, where allele ā€œcā€ had the highest relative frequency (0.525). The observed genetic variation value for Glu-D1 locus (H=0.648) exhibits the maximal polymorphism. Using cluster analysis, the relationship between the observed polymorphism and geographical variation was investigated. The results indicated that there exists a remarkable variation in Glu- A1 locus between the Iranian wheat cultivars

    Folliculogenesis and follicular fluid adiponectin in cows: Its alterations and relationships with ovarian function [Folikulogeneza i adiponektin u folikularnoj tekućini krava: Promjene i odnos s funkcijom jajnika]

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    The objectives of the present study were to study the dynamic changes in adiponectin concentration in the growing luteal as well as the preovulatory follicles in dairy cows. In the first study, the ovaries and blood of 15 Holstein dairy cows in the luteal phase were collected from a slaughterhouse. Clear antral follicles were divided into three diameter groups (small, 3-5 mm; medium, 6-9 mm and large, ā‰„10 mm) and their fluid was aspirated. In the second study, the coccygeal blood and fluid of the preovulatory follicles of eight live Holstein dairy cows were aspirated transrectally, using a transrectal-guided fine-needle. Concentrations of adiponectin in the serum, and follicular fluid and progesterone in the serum were measured. Serum adiponectin concentrations in both luteal and follicular phases were higher than the follicular fluid adiponectin concentrations in all types of follicles (P0.05), and the reduction was seen in preovulatory follicles in comparison with small follicles (P = 0.001). In the luteal phase, a significant positive correlation was observed between the adiponectin concentrations in different sized follicles, and also in the serum progesterone and follicular fluid adiponectin of follicles (P<0.05). In conclusion, lower adiponectin concentrations in blood serum and preovulatory follicles in comparison to luteal growing follicles reflect the effect of ovarian stage on adiponectin alterations

    Quantifying the impacts of ENSO and IOD on rain gauge and remotely sensed precipitation products over Australia

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    Large-scale ocean-atmospheric phenomena like the El NiƱo Southern Oscillation (ENSO) and Indian Ocean Dipole (IOD) have significant influence on Australia's precipitation variability. In this study, multi-linear regression (MLR) and complex empirical orthogonal function (CEOF) analyses were applied to isolate (i) the continental precipitation variations likely associated with ENSO and IOD, here referred to as 'ENSO/IOD mode', and (ii) the variability not associated with ENSO/IOD (the 'non-ENSO/IOD mode'). The first is of interest due to its dominant influence on inter-annual variability, while the second may reveal lower frequency variability or trends. Precipitation products used for this study included gridded rainfall estimates derived by interpolation of rain gauge data from the Australian Bureau of Meteorology (BoM), two satellite remote sensing products (CHIRP and TRMM TMPA version 7), and two weather forecast model re-analysis products (ERA-Interim and MERRA). The products covered the period 1981-2014 except TMPA (1998-2014). Statistical and frequency-based inter-comparisons were performed to evaluate the seasonal and long-term skills of various rainfall products against the BoM product. The results indicate that linear trends in rainfall during 1981-2014 were largely attributable to ENSO and IOD. Both intra-annual and seasonal rainfall changes associated with ENSO and IOD increased from 1991 to 2014. Among the continent's 13 major river basins, the greatest precipitation variations associated with ENSO/IOD were found over the Northern and North East Coast, while the smallest contributions were for Tasmania and the South West Coast basins. We also found that although the assessed products show comparable spatial variability of rainfall over Australia, systematic seasonal differences exist that were more pronounced during the ENSO and IOD events

    Characterization of Ethiopian mega hydrogeological regimes using GRACE, TRMM and GLDAS Datasets

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    Understanding the spatio-temporal characteristics of water storage changes is crucial for Ethiopia, a country that is facing a range of challenges in water management caused by anthropogenic impacts as well as climate variability. In addition to this, the scarcity of in situ measurements of soil moisture and groundwater, combined with intrinsic ā€˜ā€˜scale limitationsā€™ā€™ of traditional methods used in hydrological characterization are further limiting the ability to assess water resource distribution in the region. The primary objective of this study is therefore to apply remotely sensed and model data over Ethiopia in order to (i) test the performance of models and remotely sensed data in modeling water resources distribution in un-gauged arid regions of Ethiopia, (ii) analyze the inter-annual and seasonal variability as well as changes in total water storage (TWS) over Ethiopia, (iii) understand the relationship between TWS changes, rainfall, and soil moisture anomalies over the study region, and (iv) identify the relationship between the characteristics of aquifers and TWS changes. The data used in this study includes; monthly gravity field data from the Gravity Recovery And Climate Experiment (GRACE) mission, rainfall data from the Tropical Rainfall Measuring Mission (TRMM), and soil moisture from the Global Land Data Assimilation System (GLDAS) model. Our investigation covers a period of 8 years from 2003 to 2011.The results of the study show that the western part and the north-eastern lowlands of Ethiopia experienced decrease in TWS water between 2003ā€“2011, whereas all the other regions gained water during the study period. The impact of rainfall seasonality was also seen in the TWS changes. Applying the statistical method of Principal Component Analysis (PCA) to TWS, soil moisture and rainfall variations identified the dominant annual water variability in the western, north-western, northern, and central regions, and the dominant seasonal variability in the western, north-western, and the eastern regions. A correlation analysis between TWS and rainfall indicated a minimum time lag of zero to a maximum of six months, whereas no lag is noticeable between soil moisture anomalies and TWS changes. The delay response and correlation coefficient between rainfall and TWS appears to be related to recharge mechanisms, revealing that most regions of Ethiopia receive indirect recharge. Our results also show that the magnitude of TWS changes is higher in the western region and lower in the north-eastern region, and that the elevation influences soil moisture as well as TWS
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