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The kilosecond variability of X-ray sources in nearby galaxies

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Research in Astronomy and Astrophysics 2013年第12期13卷 1445-1454页

作者： Soma Mandal Ranjeev Misra gulab C.Dewangan Department of Physics Taki Government College Inter-University Centre for Astronomy and Astrophysics

Chandra observations of 17 nearby galaxies were analyzed and 166 bright sources with X-ray counts 〉 100 were chosen for temporal analysis. Fractional root mean square （rms） variability amplitudes were estimated for light curves, binned at 4 kilosecond （ks）, with length 〈 40 ks. While there are nine ultra-luminous X- ray sources （ULXs） with unabsorbed luminosity （in the 0.3-8.0 keV band） L 〉 1039 erg s-1 in the sample for which the fractional rms variability is constrained to be 〈 10%, only two of them show variability. One of the variable ULXs exhibits a secular transition and has an ultra-soft spectrum with temperature - 0.3 keV while the other is a rapidly varying source in NGC 0628, which has previously been com- pared to the Galactic microquasar GRS 1915＋105. These results seem to indicate that ULXs are typically not highly variable on ks timescales, except for some ultra-soft ones. Among the relatively low luminosity sources （L - 10^38 erg s-1）, we find five of them to be variable. Apart from an earlier known source in NGC 1569, we identify a source in NGC 2403 that exhibits persistent high amplitude fluctuations. In general, the variability of the sources does not seem to be correlated with hardness, which indicates that they may not be due to variations in any absorbing material, but instead could reflect instabilities in the inner accretion disk.

关键词： galaxies: general --X-rays: binaries

Intrusion Detection System Using Classification Algorithms with Feature Selection Mechanism over Real-Time Data Traffic

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China Communications 2024年第9期21卷 292-320页

作者： gulab Sah Sweety Singh Subhasish Banerjee Computer Science and Engineering National Institute of Technology Arunachal PradeshIndia

The key objective of intrusion detection systems(IDS)is to protect the particular host or network by investigating and predicting the network traffic as an attack or *** IDS uses many methods of machine learning(ML)to learn from pastexperience attack *** based and identify the new *** though these methods are effective,but they have to suffer from large computational costs due to considering all the traffic features,***,emerging technologies like the Internet of Things(Io T),big data,*** getting advanced day by day;as a result,network traffics are also increasing ***,the issue of computational cost needs to be addressed ***,in this research,firstly,the ML methods have been used with the feature selection technique(FST)to reduce the number of features by picking out only the important ones from NSL-KDD,CICIDS2017,and CIC-DDo S2019datasets later that helped to build IDSs with lower cost but with the higher performance which would be appropriate for vast scale *** experimental result demonstrated that the proposed model *** tree(DT)with Recursive feature elimination(RFE)performs better than other classifiers with RFE in terms of accuracy,specificity,precision,sensitivity,F1-score,and G-means on the investigated datasets.

关键词： CICIDS2017 dataset classifiers IDS ML NSL KDD dataset RFE

Long-Term Effects of Different Passages of Vehicular Traffic on Soil Properties and Carbon Storage of a Crosby Silt Loam in USA

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Pedosphere 2019年第2期29卷 150-160页

作者： gulab Singh YADAV Rattan LAL Ram Swaroop MEENA Basant RIMAL Carbon Management and Sequestration Centre the Ohio State University

The passage of vehicles with heavy axle loads causes soil compaction, and this adversely affects soil properties and crop *** adverse effects can persist for several years due to significant changes in key soil properties. However, the mechanisms of the aforementioned effects are not well understood for conservation agriculture(CA)(e.g., no-till(NT)) wherein the use of heavy machinery is considerably common. Therefore, known compaction forces(0 Mg load for compaction(NT-0, control), two passages of 2.5 Mg water wagon axle load(NT-2), and four passages of 2.5 Mg water wagon axle load(NT-4)) were applied to all the plots annually for 20 consecutive years. The experiment was established in 1997 at the Waterman Agricultural and Natural Resources Laboratory(WANRL), Ohio State University, Columbus, Ohio. Each treatment was replicated thrice. Soil samples were obtained in November2016 to determine the effects of variations in the axle load and vehicular passages on carbon(C) and nitrogen(N) storage and selected soil properties of a Crosby silt loam soil under NT-based corn-soybean rotation with residue retention in Central Ohio, USA. Three locations were also randomly selected in an adjoining natural woodlot(WL) soil plot and sampled(30 m away from the compaction field) to compare the effects of vehicular traffic on soil under NT with WL soil. Results revealed that soil bulk density(ρb) and total porosity at 0–10 and 10–20 cm depths were not affected by the passages of vehicular traffic for 20 years under the NT *** penetration resistance(PR)(1.86 and 2.03 MPa at 0–10 and 10–20 cm soil depths, respectively) was significantly higher under NT-4 compared with that under other treatments. Saturated hydraulic conductivity at 0–10 and 10–20 cm soil depths ranged from19.7 to 31.4 and 18.5 to 29.5 mm d^(-1), respectively, across all the treatments. The proportion of macroaggregates(> 0.25 mm) and microaggregates(< 0.25 mm), mean weight diameter and geometric mean diam

关键词： carbon stock heavy machinery no-till residue retention soil aggregates soil compaction soil quality well-drained soil

Potential of conservation tillage and altered land configuration to improve soil properties,carbon sequestration and productivity of maize based cropping system in eastern Himalayas,India

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International Soil and Water Conservation Research 2021年第2期9卷 279-290页

作者： gulab Singh Yadav Anup Das Subhash Babu Kamal Prasad Mohapatra Rattan Lal Dipjyoti Rajkhowa Indian Council of Agricultural Research(ICAR) Research Complex for North Eastern HillRegionTripura CentreTripuraIndia ICAR eIndian Agricultural Research Institute New DelhiIndia ICAR-National Bureau of Plant Genetic Resources New DelhiIndia Carbon Management and Sequestration Center Ohio State UniversityColumbusUSA ICAR Research Complex for NEH Region Nagaland CentreNagalandIndia

Poor soil properties especially low soil organic carbon(SOC)and nutrient and water retention capacities are major concern for sustainable agriculture in *** experiments were conducted to assess the effects of six combinations of tillage[conventional tillage(CT)and no-till(NT)]and land configurations[flat bed planting(FB),ridge and furrow planting(RF),and raised bed planting(RB)]on productivity and carbon(C)-sequestration potential of maize[(Zea mays L.)for green-cob in summer]-maize(for grains in rainy season)-field pea[(Pisum sativum *** winter]cropping system under humid mildtropical climate of Tripura,*** maize under NT-FB in 2012 and NT-RF in 2013 produced significantly higher green cob yield than that under ***,in rainy season,CT produced higher maize grain yield than NT *** pea seed yield was significantly the highest under *** two cropping cycles,NT systems had higher available N,P,K and 18.6e31.4%higher soil moisture content after rainy season maize than CT *** highest SOC-stock(0e30 cm)was observed under NT-FB,whereas,SOC-sequestration rate was maximum under NT-RB(0.85 Mg ha1 year1).Therefore,NT based systems can enhance the productivity and improve SOC-sequestration in cultivated soils of eastern ***,study recommended adoption of NT-RB/NT-FB to raise maize-maize-field pea system for improving productivity,improving C-sequestration and soil properties in the eastern Himalayas and similar eco-regions elsewhere.

关键词： Soil fertility Carbon sequestration Soil moisture Low productivity Hill ecosystem

On the reality of broad iron L lines from the narrow line Seyfert 1 galaxies 1H0707–495 and IRAS 13224–3809

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Research in Astronomy and Astrophysics 2016年第11期16卷 37-42页

作者： Pramod Karbhari Pawar gulab Chand Dewangan Madhav Khushalrao Patil Ranjeev Misra Sharada Keshav Jogadand S. R. T. M. University Nanded- 431 606 India Inter-University Center for Astronomy and Astrophysics Pune - 411 007 India

We performed time resolved spectroscopy of 1H0707-495 and IRAS 13224-3809 using long XMM-Newton observations. These are strongly variable narrow line Seyfert 1 galaxies and show broad features around 1 keV that have been interpreted as relativistically broad Fe Lc~ lines. Such features are not clearly observed in other active galactic nuclei despite sometimes having high iron abundance required by the best fitted blurred reflection models. Given the importance of these lines, we explore whether the rapid variability of spectral parameters may introduce broad bumps/dips artificially in the time averaged spectrum, which may then be mistaken as broadened lines. We tested this hypothesis by performing time resolved spectroscopy using long （〉 100 ks） XMM-Newton observations and by dividing them into segments with typical exposures of a few ks. We extracted spectra from each such segment and modeled them using a two component phenomenological model consisting of a power law to represent the hard component and a black body to represent the soft emission. As expected, both the sources showed variations in the spectral parameters. Using these variation trends, we simulated model spectra for each segment and then co-added to get a combined simulated spectrum. In the simulated spectra, we found no broad features below 1 keV and in particular no deviation near 0.9 keV as seen in the real averaged spectra. This implies that the broad Fe Lα line that is seen in the spectra of these sources is not an artifact of the variation of spectral components and, hence, provides evidence that the line is indeed genuine.

关键词： galaxies: general -- galaxies: active -- galaxies: individual (1H0707-495 IRAS 13224-3809)

Microscopic and metabolic investigations disclose the factors that lead to skin cracking in chili-type pepper fruit varieties

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Horticulture Research 2023年第4期10卷 211-224页

作者： Ofir Marinov Gal Nomberg Sutanni Sarkar gulab Chand Arya Eldad Karavani Einat Zelinger Ekaterina Manasherova Hagai Cohen Department of Vegetable and Field Crops Institute of Plant SciencesAgricultural Research Organization(ARO)Volcani InstituteRishon LeZion 7505101Israel Department of Plant Pathology and Microbiology The Robert H.Smith Faculty of AgricultureFood and EnvironmentThe Hebrew University of JerusalemRehovot 7610001Israel Center for Scientific Imaging(CSI) The Robert H.Smith Faculty of AgricultureFood and EnvironmentThe Hebrew University of JerusalemRehovot 7610001Israel

The hydrophobic cuticle encasing the fruit skin surface plays critical roles during fruit development and *** failure often results in the fruit surface cracking and forming a wound-periderm tissue made of suberin and *** factors that make the fruit skin susceptible to cracking have yet to be fully ***,we investigated two varieties of chili peppers(Capsicum annuum L.),Numex Garnet,whose fruit has intact skin,and Vezena Slatka,whose fruit has cracked *** observations,gas chromatography-mass spectrometry,biochemical and gene expression assays revealed that Vezena Slatka fruit form a thicker cuticle with greater levels of cutin monomers and hydroxycinnamic acids,and highly express key cutin-related *** skin of these fruit also had a lower epidermal cell density due to cells with very large perimeters,and highly express genes involved in epidermal cell *** demonstrate that skin cracking in the Vezena Slatka fruit is accompanied by a spatial accumulation of lignin-like polyphenolic compounds,without the formation of a typical wound-periderm tissues made of suberized ***,we establish that skin cracking in chili-type pepper significantly affects fruit quality during post-harvest storage in a temperature-dependent *** conclusion,our data highlight cuticle thickness and epidermal cell density as two critical factors determining fruit skin susceptibility to cracking in chili-type pepper fruit.

关键词： varieties pepper cracking

UV and X-ray variability of the narrow-line Seyfert 1 galaxy Ark 564

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Research in Astronomy and Astrophysics 2016年第7期16卷 69-76页

作者： Savithri H.Ezhikode gulab C.Dewangan Ranjeev Misra Shruti Tripathi Ninan Sajeeth Philip Ajit K.Kembhavi Department of Physics St. Thomas College Kozhencherry Kerala 689641 India Inter-University Centre for Astronomy & Astrophysics Post Bag 4 Ganeshkhind Pune 411 007 India Physics Department Bishop's University 2600 College Street Sherbrooke QC J1M1Z7 Canada

We analyze eight XMM-Newton observations of the bright Narrow Line Seyfert 1 galaxy Arakelian 564（Ark 564）. These observations, separated bye^6 days, allow us to look for correlations between the simultaneous ultraviolet（UV） emission（from th Optical Monitor） with not only the X-ray flux but also with different X-ray spectral parameters. The X-ray spectra from all the observations are found to be adequately fitted by a double Comptonization model where the soft excess and the hard X-ray power law are represented by thermal Comptonization in a low temperature plasma and hot corona, respectively. Apart from the fluxes of each component, the hard X-ray power law index is found to be variable. These results suggest that the variability is associated with changes in the geometry of the inner region. The UV emission is found to be variable and well correlated with the high energy index while the correlations with the fluxes of each component are found to be weaker. Using viscous timescale arguments we rule out the possibility that the UV variation is due to the fluctuating accretion rate in the outer disk. If the UV variation is driven by X-ray reprocessing, then our results indicate that the strength of the X-ray reprocessing depends more on the geometry of the X-ray producing inner region rather than on the X-ray luminosity alone.

关键词： galaxies active galaxies Seyfert galaxies individual(Ark 564) X-rays galaxies

Double mulching improves soil properties and productivity of maize-based cropping system in eastern Indian Himalayas

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International Soil and Water Conservation Research 2020年第3期8卷 308-320页

作者： Bidyapati Ngangom Anup Das Rattan Lal Ramkrushna Gandhiji Idapuganti Jayanta Layek Savita Basavaraj Subhash Babu gulab Singh Yadav Probir Kumar Ghosh ICAR Research Complex for NEH Region UmiamMeghalayaIndia Krishi Vigyan Kendra-ICAR Research Complex for NEH Region Arunachal Pradesh CentreBasarArunachal PradeshIndia College of Post Graduate Studies Central Agricultural UniversityUmiamMeghalayaIndia ICAR Research Complex for NEH Region Tripura CentreLembucherraTripuraIndia Carbon Management and Sequestration Centre Ohio State UniversityUSA ICAR-Central Institute for Cotton Research NagpurMaharashtraIndia ICAR-KrishiVigyan Kendra IndiUniversity of Agricultural SciencesDharwadIndia ICAR-Indian Agricultural Research Institute New DelhiIndia ICAR-National Institute of Biotic Stress Management RaipurChhattisgarhIndia

A field experiment was conducted for two consecutive years at North Eastern Indian Himalayan region to assess the effect of soil moisture conservation measures on soil and water productivity of different rainfed maize(Zea mays L.)-based cropping *** revealed that double mulching with in-situ maize stover mulch(MSM)+fresh biomass of white hoary pea(WHP-Tephrosia candida)and MSM+fresh biomass of ragweed(RW-Ambrosia artemisiifolia)improved soil moisture content(SMC)and leaf relative water content of crops during dry *** soil organic carbon(SOC)content and stocks under MSM+WHP and MSM+RW mulches were significantly higher than that under no mulch at 0-15 cm *** soil microbial biomass carbon and dehydrogenase activity were maximum under MSM+WHP/*** highest system productivity was obtained from maize-French bean(Pole type-PT)sequence under MSM+RW followed by MSM+*** water productivity was the highest under MSM+*** SOC content was the highest under maize-French bean(PT),the maximum plant available nitrogen and phosphorus were obtained under maize-black gram ***,double mulching technology involving MSM and RW(available in plenty)is a viable option for improving soil,crop and water productivity under rainfed hill ecosystems of eastern Indian Himalayas.

关键词： Cropping systems Rainfed agriculture Residual soil moisture Soil properties Water productivity

Griseofulvin enantiomers and bromine-containing griseofulvin derivatives with antifungal activity produced by the mangrove endophytic fungus Nigrospora ***1

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Marine Life Science & Technology 2024年第1期6卷 102-114页

作者： Ge Zou Wencong Yang Tao Chen Zhaoming Liu Yan Chen Taobo Li gulab Said Bing Sun Bo Wang Zhigang She School of Chemistry Sun Yat-sen UniversityGuangzhou 510275China State Key Laboratory of Applied Microbiology Southern China Guangdong Provincial Key Laboratory of Microbial Culture Collection and ApplicationInstitute of MicrobiologyGuangdong Academy of SciencesGuangzhou 510070China School of Pharmacy Anhui Medical UniversityHefei 230032China Department of Chemistry Women University SwabiSwabi 23430Pakistan

Marine microorganisms have long been recognized as potential sources for drug *** was one of the first antifungal natural products and has been used as an antifungal agent for *** this study,12 new griseofulvin derivatives[(±)-1-2,(+)-3,(±)-4,10-12,and 14-15]and two new griseofulvin natural products(9 and 16)together with six known analogues[(-)-3,5-8,and 13]were isolated from the mangrove-derived fungus Nigrospora ***1 treated with 0.3%NaCl or 2%NaBr in rice solid *** 2D structures and absolute configurations were established by extensive spectroscopic analysis(1D and 2D NMR,HRESIMS),ECD spectra,computational calculation,DP4+analysis,and X-ray single-crystal *** 1-4 represent the first griseofulvin enantiomers with four absolute configurations(2S,6'S;2R,6'R;2S,6'R;2R,6'S),and compounds 9-12 represent the first successful production of brominated griseofulvin derivatives from fungi via the addition of NaBr to the culture *** the antifungal assays,compounds 6 and 9 demonstrated significant inhibitory activities against the fungi Colletotrichum truncatum,Microsporum gypseum,and Trichophyton mentagrophyte with inhibition zones varying between 28 and 41 mm(10μg/disc).The structure-activity relationship(SAR)was analyzed,which showed that substituents at C-6,C-7,C-6'and the positions of the carbonyl and double bond of griseofulvin derivatives significantly affected the antifungal activity.

关键词： Mangrove endophytic fungus Nigrospora sp. Griseofulvin Antifungal activity