Wyniki wyszukiwania - Biblioteka Nauki

1

Automated and effective content-based mammogram retrieval using wavelet based CS-LBP feature and self-organizing map

100%

Singh V. P. , Srivastava R.

Biocybernetics and Biomedical Engineering

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2018

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tom Vol. 38, no. 1

90--105

EN

In this paper, automated, fast and effective content based-mammogram image retrieval system is proposed. The proposed pre-processing steps include automatic labelling-scratches suppression, automatic pectoral muscle removal and image enhancement. Further, for segmentation selective thresholds based seeded region growing algorithm is introduced. Furthermore, we apply 2-level discrete wavelet transform (DWT) on the segmented region and wavelet based centre symmetric-local binary pattern (WCS-LBP) features are extracted. Then, extracted features are fed to self-organizing map (SOM) which generates clusters of images, having similar visual content. SOM produces different clusters with their centres and query image features are matched with all cluster representatives to find closest cluster. Finally, images are retrieved from this closest cluster using Euclidean distance similarity measure. So, at the searching time the query image is searched only in small subset depending upon cluster size and is not compared with all the images in the database, reflects a superior response time with good retrieval performances. Descriptive experimental and empirical discussions confirm the effectiveness of this paper.

2

The role of abscisic acid (ABA) in ethylene insensitive Gladiolus (Gladiolus grandiflora Hort.) flower senescence

80%

Kumar M. , Singh V. P. , Arora A. , Singh N.

Acta Physiologiae Plantarum

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2014

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tom 36

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nr 01

EN

Gladiolus flowers are ethylene insensitive and the signals that start catabolic changes during senescence of gladiolus flower are largely not known. Therefore, experiments were performed to understand the role of abscisic acid (ABA) in ethylene insensitive floral senescence in gladiolus (Gladiolus grandiflora Hort.). It was observed that ABA accumulation increased in attached petals of gladiolus flowers as they senesced. Exogenous application of ABA in vase solution accelerated senescence process in the flowers due to change in various senescence indicators such as enhanced membrane leakage, reduced water uptake, reduced fresh weight and ultimately vase life. Enhancement of in vivo ABA level in petals by creating osmotic stress also upregulates the same parameters of flower senescence as those occurring during natural senescence and also akin to exogenous application of ABA. Attempts to increase vase life of flowers by application of putative ABA biosynthesis inhibitor fluridone in vase solution to counteract ABA effect were unsuccessful. In contrast, ABA action was mitigated by application of GA₃ in holding solution along with ABA which is basically an antagonist of ABA action. The present study provides valuable insights into the role of ABA as a hormonal trigger in ethylene insensitive senescence process and therefore would be helpful for dissecting the complex mechanism underlying ABA-regulated senescence process in gladiolus.

3

On the informative value of the largest sample element of log-Gumbel distribution

80%

Strupczewski W. G. , Kochanek K. , Singh V. P.

Acta Geophysica

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2007

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tom Vol. 55, no. 4

652-678

EN

Extremes of stream flow and precipitation are commonly modeled by heavy-tailed distributions. While scrutinizing annual flow maxima or the peaks over threshold, the largest sample elements are quite often suspected to be low quality data, outliers or values corresponding to much longer return periods than the obser-vation period. Since the interest is primarily in the estimation of the right tail (in the case of floods or heavy rainfalls), sensitivity of upper quantiles to largest elements of a series constitutes a problem of special concern. This study investigated the sen-sitivity problem using the log-Gumbel distribution by generating samples of different sizes (n) and different values of the coefficient of variation by Monte Carlo ex-periments. Parameters of the log-Gumbel distribution were estimated by the prob-ability weighted moments (PWMs) method, method of moments (MOMs) and maximum likelihood method (MLM), both for complete samples and the samples deprived of their largest elements. In the latter case, the distribution censored by the non-exceedance probability threshold, FT , was considered. Using FT instead of the censored threshold T creates possibility of controlling estimator property. The effect of the FT value on the performance of the quantile estimates was then examined. It is shown that right censoring of data need not reduce an accuracy of large quantile estimates if the method of PWMs or MOMs is employed. Moreover allowing bias of estimates one can get the gain in variance and in mean square error of large quantiles even if ML method is used.

4

Impact of exogenous sislicon addition on chromium uptake, growth, mineral elements, oxidative stress, antioxidant capacity, and leaf and roots structures in rice seedlings exposed to hexavalent chromium

80%

Tripathi D. K. , Singh V. P. , Kumar D. , Chauhan D. K.

Acta Physiologiae Plantarum

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2012

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tom 34

|

nr 1

EN

Hydroponic experiments were conducted to investigate the role of exogenous silicon (Si) addition in increasing hexavalent chromium (Cr VI) tolerance in rice seedlings. Rice seedlings were grown under 100 µM Cr(VI) stress without or with 10 µM Si. Chromium treatment decreased growth, photosynthetic pigments and protein, which was accompanied by a significant increase in Cr accumulation and lipid peroxidation (as malondialdehyde; MDA). However, Si addition alleviated Cr toxicity and promoted growth of rice by decreasing Cr accumulation, root-to-shoot Cr transport and MDA level. Contents of macro (Mg, Ca and K) as well as micronutrients (Zn and Fe) were decreased by Cr except Mn while Si addition prevented decrease in these nutrients induced by Cr. Antioxidant capacity and total phenolic contents were decreased by Cr while these indices improved by Si addition. Treatment of Cr decreased the length of leaf epidermal cells and stomatal frequency, and adversely affected chloroplasts containing mesophyll cells and integrity of xylem and phloem, and Si addition minimized these abnormalities. However, frequency of root hairs was increased by Cr treatment. Results showed that exogenous Si addition enhanced Cr(VI) tolerance in rice seedlings by decreasing Cr accumulation, root-to-shoot Cr transport and MDA level, and by increasing content of some mineral elements (K, Fe and Zn) and antioxidant capacity compared to the Cr treatment alone.

5

Stress pattern in two seismogenic sources in Nepal-Himalaya and its vicinity

80%

Paudyal H. , Singh H. N. , Shanker D. , Singh V. P.

Acta Geophysica

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2008

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tom Vol. 56, no. 2

313-323

EN

The composite stereographic projection of orientations of the compression and tension axes using thirty-nine fault-plane solutions of earthquakes from two active seismogenic sources of Nepal and adjoining areas were examined and the nature of stress pattern and their influence on tectonics in the region have been studied. The seismogenic source located in Eastern Nepal region, which has been the site of 1934 Bihar-Nepal great earthquake of M 8.4, is presently experiencing N-S to NE-SW directed compressive stresses. The inferred pattern of compression axes in Western Nepal region suggests a shallow compressive stress, dipping N-S to NE-SW. Approximately similar nature of the stress regime is observed in Western and Eastern regions of Nepal, separated by nearly 700 km; it shows N-S to NNE-SSW direction of compression and underthrusting of the Indian Plate beneath the Himalaya at a shallow angle. Present study indicates that the stress is being released along the strikes of some of the transverse faults present in the region since the compressive stress exerted by the northward movement of the Indian Plate is approximately perpendicular to the Himalayan collision belt. Unilateral stress pattern generated by the northward movement of the Indian Plate in the central part of the Himalaya reveals that the present day collision occurs roughly perpendicular to the local strike of the Himalaya.

6

Modification of chromium (VI) phytotoxicity by exogenous gibberellic acid application in Pisum sativum (L.) seedlings

80%

Gangwar S. , Singh V. P. , Srivastava P. K. , Maurya J. N.

Acta Physiologiae Plantarum

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2011

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tom 33

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nr 4

EN

Effects of exogenous gibberellic acid (GA; 10 and 100 µM) application on growth, protein and nitrogen contents, ammonium (NH₄⁺) content, enzymes of nitrogen assimilation and antioxidant system in pea seedlings were investigated under chromium (VI) phytotoxicity (Cr VI; 50, 100 and 250 µM). Exposure of pea seedlings to Cr and 100 µM GA resulted in decreased seed germination, fresh and dry weight and length of root and shoot, and protein and nitrogen contents compared to control. Compared to control, Cr and 100 µM GA led to the significant alteration in nitrogen assimilation in pea. These treatments decreased root and shoot nitrate reductase (NR), glutamine synthetase (GS) and glutamine 2-oxoglutarate aminotransferase (GOGAT) activities (except 50 µM Cr alone for GOGAT) while glutamate dehydrogenase (GDH) activity and NH₄⁺ content increased. Compared to control, the root and shoot activities of superoxide dismutase (SOD) and ascorbate peroxidase (APX) increased (except APX activity at 250 µM Cr + 100 µM GA) while catalase (CAT), glutathione reductase (GR) and dehydroascorbate reductase (DHAR) activities were decreased (except GR at 100 µM GA alone) following exposure of Cr and 100 µM GA. Total ascorbate and total glutathione in root and shoot decreased by the treatments of Cr and 100 µM GA while their levels were increased by the application of 10 µMGA compared to Cr treatments alone. It has been reported that application of 10 µM GA together with Cr alleviated inhibited levels of growth, nitrogen assimilation and antioxidant system compared to Cr treatments alone. This study showed that application of 10 µM GA counteracts some of the adverse effects of Cr phytotoxicity with the increased levels of antioxidants and sustained activities of enzymes of nitrogen assimilation; however, 100 µM GA showed apparently reverse effect under Cr phytotoxicity.

7

Impact of low and high fluence rates of UV-B radiation on growth and oxidative stress in Phormidium foveolarum and Nostoc muscorum under copper toxicity: differential display of antioxidants system

80%

Singh V. P. , Srivastava P. K. , Prasad S. M.

Acta Physiologiae Plantarum

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2012

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tom 34

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nr 6

EN

In the present study, impact of low (UV-BL) and high (UV-BH) fluence rates of UV-B on growth, oxidative stress and antioxidant system was studied in two cyanobacteria i.e. Phormidium foveolarum and Nostoc muscorum under Cu (2 and 5 µM) toxicity after 24 and 72 h of experiments. UV-BH and Cu treatment decreased growth of both the cyanobacteria and Cu induced decrease in growth was accompanied by a significant increase in Cu accumulation. Levels of reactive oxygen species (ROS), i.e. superoxide radicals (SOR; O₂⁻ ) and hydrogen peroxide (H₂O₂) were significantly increased by Cu and UV-BH exposure which in turn accelerated lipid peroxidation (malondialdehyde: MDA) and protein oxidation (reactive carbonyl groups: RCG). Activities of enzymatic antioxidants, such as superoxide dismutase (SOD), peroxidase (POD) and glutathione-S-transferase (GST) were increased by both doses of Cu as well as UV-B. Conversely, Cu and UV-BH drastically decreased catalase (CAT) activity. After the commencement of 24 h of treatment with Cu alone and together with UV-BH, non-protein thiols (NP-SH) contents were decreased while after 72 h, a reverse trend was noticed. Unlike NP-SH, cysteine content decreased appreciably during the treatments. In contrast to this, low dose (UV-BL) of UV-B did not influence growth, SOR, H₂O₂, MDA and RCG contents. An improvement in CAT activity and NP-SH content was observed under Cu and UV-BL treatment; hence, UV-BL treatment resulted into certain degree of protection against Cu toxicity in both the organisms. Thus, the results showed that UV-BH and UVBL exerted differential effects on both the organisms under Cu toxicity, and compared to N. muscorum, P. foveolarum was less affected by Cu and UV-BH.

8

Differential responses of pea seedlings to indole acetic acid under manganese toxicity

80%

Gangwar S. , Singh V. P. , Prasad S. M. , Maurya J. N.

Acta Physiologiae Plantarum

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2011

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tom 33

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nr 2

EN

Present study showed the responses of pea seedlings to exogenous indole acetic acid (IAA; 10 and 100 µM) application under manganese (Mn; 50, 100 and 250 µM) toxicity. Manganese and 100 µM IAA alone as well as in combination decreased growth of pea seedlings compared to control. Moreover, some parameters of oxidative stress—hydrogen peroxide (H₂O₂) and malondialdehyde (MDA) were also increased by single and combined treatments of Mn and 100 µM IAA compared to control. In contrast, addition of 10 µM IAA together with Mn, alleviated Mn toxicity symptoms and promoted growth led to the decrease in H₂O₂ and MDA levels compared to Mn treatments alone. Under single and combined treatments of Mn and 100 µM IAA, catalase activity decreased while superoxide dismutase and ascorbate peroxidase activities increased and glutathione reductase and dehydroascorbate reductase exhibited differential responses. However, addition of 10 µM IAA together with Mn, increased activities of studied enzymatic antioxidants. Root and shoot reduced ascorbate (AA) and reduced glutathione (GSH) and, their reduced/oxidized ratios decreased while dehydroascorbate (DHA) and oxidized glutathione (GSSG) contents increased compared to control following single and combined treatments of Mn and 100 µM IAA. However, supply of 10 µM IAA together with Mn, increased AA and GSH, and their reduced/oxidized ratios in root and shoot compared to Mn treatments alone. This study thus suggests that 10 µM of IAA was able to increase Mn tolerance in pea seedlings under Mn toxicity while opposite was noticed for 100 µM IAA.

9

Genetic of some grain characters in hexaploid Triticale

80%

Behl R. K. , Singh V. P. , Spalony L.

Genetica Polonica

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1985

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tom 26

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nr 4

10

Are parsimonious FF models more reliable than true ones? I. Accuracy of Quantiles and Moments Estimation (AQME) - method of assessment

80%

Strupczewskiwgs@igf.edu.pl W. G. , Kochanek K. , Singh V. P. , Węglarczyk S.

Acta Geophysica Polonica

|

2005

|

tom Vol. 53, nr 4

419-436

EN

Applying the methodology described in Strupczewski et al. (2005a; this is-sue), the performance of various parsimonious models combined with three estimation methods versus Flood Parent Distributions is comparatively assessed by simulation experiments. Moments (MOM), L-moments (LMM) and maximum likelihood (MLM) are used as alternative methods. Five four-parameter Specific Wakeby Distributions (SWaD) are employed to serve as Flood Parent Distributions and forty Distribution/Estimation (D/E) procedures are included in respect to the estimation of upper quantiles. The relative bias (RB), relative root mean square error (RRMSE) and reliability of procedures are used for the assessment of the relative performance of alternative procedures. Parsimonious two-parameter models generally perform better for hydrological sample sizes than their three-parameter counterparts with respect to RRMSE. How-ever, the best performing procedures differ for various SWaDs. As far as estimation methods are concerned, MOM usually produces the smallest values of both RB and RRMSE of upper quantiles for all competing methods. The second place in rank is occupied by LMM, whereas, MLM produces usually the highest values. Considerable influence of sampling bias on the value of the total bias has been ascertained. The improper choice of a model fitted to SWaD samples causes that the reli-ability of some three-parameter parsimonious D/E procedures does not always rise with the sample size. Also odd is that True model does not always give one hundred percent reliability for very large samples, as it should. This means that estimating algorithms still require improvements.

11

Are parsimonious FF models more reliable than true ones? II. Comparative assessment of the performance of simple models versus the parent distributions

80%

Kochanek K. , Strupczewski W. G. , Singh V. P. , Węglarczyk S.

Acta Geophysica Polonica

|

2005

|

tom Vol. 53, nr 4

437-457

EN

Applying the methodology described in Strupczewski et al. (2005a; this issue), the performance of various parsimonious models combined with three estima-tion methods versus Flood Parent Distributions is comparatively assessed by simulation experiments. Moments (MOM), L-moments (LMM) and maximum likelihood (MLM) are used as alternative methods. Five four-parameter Specific Wakeby Distributions (SWaD) are employed to serve as Flood Parent Distributions and forty Distribution/Estimation (D/E) procedures are included in respect to the estimation of upper quantiles. The relative bias (RB), relative root mean square error (RRMSE) and reliability of procedures are used for the assessment of the relative performance of alternative procedures. Parsimonious two-parameter models generally perform better for hydrological sample sizes than their three-parameter counterparts with respect to RRMSE. How-ever, the best performing procedures differ for various SWaDs. As far as estimation methods are concerned, MOM usually produces the smallest values of both RB and RRMSE of upper quantiles for all competing methods. The second place in rank is occupied by LMM, whereas, MLM produces usually the highest values. Considerable influence of sampling bias on the value of the total bias has been ascertained. The improper choice of a model fitted to SWaD samples causes that the reliability of some three-parameter parsimonious D/E procedures does not always rise with the sample size. Also odd is that True model does not always give one hundred percent reliability for very large samples, as it should. This means that estimating algorithms still require improvements.

12

Light intensity determines the extent of mercury toxicity in the cyanobacterium Nostoc muscorum

70%

Singh R. , Srivastava P. K. , Singh V. P. , Dubey G. , Prasad S. M.

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nr 3

EN

The extent of mercury (Hg) toxicity in the heterocystous cyanobacterium Nostoc muscorum grown for 72 h in three different light intensities was tested for various physiological parameters viz. growth, pigment contents, photosynthesis, respiration, reactive oxygen species (ROS), malondialdehyde formation and antioxidants. A general reduction in growth and pigments, whole cell O₂- evolution, photosynthetic electron transport activities and ¹⁴CO₂-fixation was observed in a metal concentration–dependent manner, and this effect was more pronounced in high light (130 µmol photon m⁻² s⁻¹)–exposed cells as compared to low (10 µmol photon m⁻² s⁻¹) and normal (70 µmol photon m⁻² s⁻¹) light intensity–exposed cells; however, carotenoids and respiration showed reverse trend. Among photosynthetic electron transport activities, whole chain activity was found to be most sensitive in comparison with photosystem II (PS II) and photosystem I (PS I). Comparing the different photosynthetic processes, ¹⁴CO₂-fixation was most affected in cyanobacterial cells when exposed to Hg and different light intensities. After application of various exogenous electron donors, diphenyl carbazide was found to be more effective to restore PS II activity, suggesting that site of damage lies in between oxygen evolving complex and PS II. Level of oxidative stress (superoxide radical and lipid peroxidation) was maximum at 3.0 µM of Hg when coupled with high light intensity (except hydrogen peroxide). A dose-dependent increase in enzymatic antioxidants such as superoxide dismutase, peroxidase and catalase as well as non-enzymatic antioxidants such as proline, ascorbate, cysteine (except under high light intensity) and non-protein thiols [NP-SH] was observed, which further increased with the increase in light intensity. It was noticed that Hg intoxicates N. muscorum through ROS production, which is aggravated along with the increase in light intensity. Overall results suggest that the severity of the metal stress does increase with Hg concentrations but when coupled with light, it was the light intensity that determines the extent of Hg toxicity.

13

Occurrence and distribution of Rhizobiophages in Indian soils

70%

Dhar B. , Singh B. D. , Srivastava J. S. , Singh V. P. , Singh R. M.

Acta Microbiologica Polonica

|

1979

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tom 28

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nr 4

14

Assessment of terminal heat tolerance ability of wheat genotypes based on physiological traits using multivariate analysis

70%

Nagar S. , Singh V. P. , Arora A. , Dhakar R. , Ramakrishnan S.

Acta Physiologiae Plantarum

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2015

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tom 37

|

nr 12

EN

Terminal heat stress is one of the limiting factors in wheat production and it is expected to rise under present scenario of climate change. The present study was conducted to evaluate the performance of 40 wheat genotypes under terminal heat stress conditions based on eight physiological traits. The plants were sown late (i.e. on 5th January) to expose them terminal heat stress. The genotypes were evaluated using multivariate analysis viz. Ward’s method of hierarchical clusters analysis, discriminant analysis and principle component analysis. The genotypes were categorized into three groups namely tolerant, intermediate and sensitive. Tolerant genotypes like DBW 14, RAJ 3765, HD 2643 and HALNA performed physiologically better in terms of higher membrane stability index (MSI), chlorophyll content, photosynthesis rate (Pn), harvest index under heat stress conditions. Genotypes HD 2987, SHANGHAI, HD 2402 and WH 730 were found to be heat sensitive. Physiological traits like MSI, SPAD value, Fv/Fm ratio and Pn were found to be most important contributor in grouping of genotypes and showed positive correlations (r) of 0.73, 0.47, 0.41 and 0.39 with grain yield, respectively, which is significant at p<0.05. The large genetic diversity was found among the genotypes based on physiological traits. These genotypes can be utilized in wheat improvement programme for heat tolerance.

15

Fungal spore germination inhibition by alkaloids dehydrocorydalmine and oxyberberine

61%

Singh A. , Singh S. , Singh S. , Singh T. D. , Singh V. P. , Pandey V. B. , Singh U. P.

Journal of Plant Protection Research

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2009

|

tom 49

|

nr 3

287-289

EN

The alkaloids dehydrocorydalmine and oxyberberine isolated from Argemone mexicana were assessed against spore germination of some fungi, e.g., Alternaria cajani, Bipolaris sp., Helminthosporium sp., Fusarium udum and Curvularia sp. While dehydrocorydalmine inhibited 100% spore germination of the fungi Helminthosporium sp. and Curvularia sp. at 5 000 ppm, oxyberberine showed similar activity against spore germination of Bipolaris sp. and Curvularia sp. All the five fungi were significantly inhibited at 1 000 to 5 000 ppm concentrations.

PL

Określano wpływ alkaloidów dehydrokorydalminy i oksyberberyny wyosobnionych z Argemone mexicana na kiełkowanie zarodników niektórych grzybów, w tym Alternaria cajani, Bipolaris sp., Helminthosporium sp., Fusarium udum i Curvularia sp. Podczas gdy dehydrokory-dalmina inhibowała w 100% kiełkowanie zarodników grzybów Helminthosporium sp. i Curvularia sp. w stężeniu 5 000 ppm, oksyberberyna wykazywała podobną aktywność przeciwko kiełkowaniu zarodników Biopolaris sp. i Curvularia sp. Wszystkie pięć grzybów było istotnie inhibitowane w stężeniach od 1 000 do 5 000 ppm.