NONSELECTIVE HARVESTING OF A PEY-PREDATOR COMMUNITY WITH

Ghosh, Dipanwita,Sarkar, A.K. 한국전산응용수학회 1999 Journal of applied mathematics & informatics Vol.6 No.3

The present paper deals with the problem of nonselective harvesting in a partly infecte prey and predator system in which both the suseptible prey and the predator follow the law of logistic growth and some preys avoid predation by hiding. The dynamical behaviour of the system has been studied in both the local and global sense. The optimal policy of exploitation has been derived by using Pontraygin's maximal principle. Numerical analysis and computer simulation of the results have been performed to inverstigate the global properties of the system.

Temperature-Independent Catalytic Two-Electron Reduction of Dioxygen by Ferrocenes with a Copper(II) Tris[2-(2-pyridyl)ethyl]amine Catalyst in the Presence of Perchloric Acid

Das, Dipanwita,Lee, Yong-Min,Ohkubo, Kei,Nam, Wonwoo,Karlin, Kenneth D.,Fukuzumi, Shunichi American Chemical Society 2013 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.135 No.7

<P>Selective two-electron plus two-proton (2e<SUP>–</SUP>/2H<SUP>+</SUP>) reduction of O<SUB>2</SUB> to hydrogen peroxide by ferrocene (Fc) or 1,1′-dimethylferrocene (Me<SUB>2</SUB>Fc) in the presence of perchloric acid is catalyzed efficiently by a mononuclear copper(II) complex, [Cu<SUP>II</SUP>(tepa)]<SUP>2+</SUP> (<B>1</B>; tepa = tris[2-(2-pyridyl)ethyl]amine) in acetone. The <I>E</I><SUB>1/2</SUB> value for [Cu<SUP>II</SUP>(tepa)]<SUP>2+</SUP> as measured by cyclic voltammetry is 0.07 V vs Fc/Fc<SUP>+</SUP> in acetone, being significantly positive, which makes it possible to use relatively weak one-electron reductants such as Fc and Me<SUB>2</SUB>Fc for the overall two-electron reduction of O<SUB>2</SUB>. Fast electron transfer from Fc or Me<SUB>2</SUB>Fc to <B>1</B> affords the corresponding Cu<SUP>I</SUP> complex [Cu<SUP>I</SUP>(tepa)]<SUP>+</SUP> (<B>2</B>), which reacts at low temperature (193 K) with O<SUB>2</SUB>, however only in the presence of HClO<SUB>4</SUB>, to afford the hydroperoxo complex [Cu<SUP>II</SUP>(tepa)(OOH)]<SUP>+</SUP> (<B>3</B>). A detailed kinetic study on the homogeneous catalytic system reveals the rate-determining step to be the O<SUB>2</SUB>-binding process in the presence of HClO<SUB>4</SUB> at lower temperature as well as at room temperature. The O<SUB>2</SUB>-binding kinetics in the presence of HClO<SUB>4</SUB> were studied, demonstrating that the rate of formation of the hydroperoxo complex <B>3</B> as well as the overall catalytic reaction remained virtually the same with changing temperature. The apparent lack of activation energy for the catalytic two-electron reduction of O<SUB>2</SUB> is shown to result from the existence of a pre-equilibrium between <B>2</B> and O<SUB>2</SUB> prior to the formation of the hydroperoxo complex <B>3</B>. No further reduction of [Cu<SUP>II</SUP>(tepa)(OOH)]<SUP>+</SUP> (<B>3</B>) by Fc or Me<SUB>2</SUB>Fc occurred, and instead <B>3</B> is protonated by HClO<SUB>4</SUB> to yield H<SUB>2</SUB>O<SUB>2</SUB> accompanied by regeneration of <B>1</B>, thus completing the catalytic cycle for the two-electron reduction of O<SUB>2</SUB> by Fc or Me<SUB>2</SUB>Fc.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jacsat/2013/jacsat.2013.135.issue-7/ja312523u/production/images/medium/ja-2012-12523u_0011.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ja312523u'>ACS Electronic Supporting Info</A></P>

Evaluation of machine learning algorithms to Sentinel SAR data

Ashish Navale,Dipanwita Haldar 대한공간정보학회 2020 Spatial Information Research Vol.28 No.3

The present study uses multi-temporal Sentinel- 1 SAR dataset for classification of Saharanpur area in the Indo-Gangetic plains with December, January and February month datasets of VV and VV/VH polarization. Support Vector Machine (SVM), Random Forest (RF), Decision Tree (DT) and Artificial Neural Network (ANN) algorithms with six different band combinations was used to classify the data in 6 classes. The highest accuracy was achieved with SVM for December–January combination with Overall Accuracy of 74.36% and a kappa coefficient of 0.6905. SVM algorithm performed the best followed by DT, ANN and RF. It was observed that the accuracy of classification increased with multi-temporal datasets. In SVM and RF the accuracy increased by almost 8% from single to dual date, but no increase in accuracy was observed irrespective of taking three dates. For DT and ANN, the accuracy from single to dual date increased by[10% and by approximately 3% (Marginal) for three dates. The single date ANN achieved very poor results but with an increase in the datasets, good accuracy was attained. This study, therefore, reveals that with single and dual datasets, SVM and RF performs well and with multitemporal datasets, DT and ANN can also achieve good accuracy.

Condition assessment of pearl millet/ bajra crop in different vigour zones using Radar Vegetation Index

Selvaraj Shanmugapriya,Haldar Dipanwita,Srivastava Hari Shanker 대한공간정보학회 2021 Spatial Information Research Vol.29 No.5

The study was focused on assessing the condition of pearl millet crop in critical growth stages using both polarimetric Radarsat-2 and dual-polarized Sentinel-1 datasets. The results revealed that bajra having a close structured phenology like maize and Jowar, exhibited significant changes in RVI due to differences in the crop calendar dates. For bajra, polarimetric RVI generated from information rich Radarsat-2 was observed to have a higher level of saturation till 6 kgm-2 biomass with a R2 of 0.7. In all instances, RVI exhibited a significant relationship with VWC and plant volume with a R2 above 0.7 due to its higher sensitivity towards crop dielectric constant. Unlike NDVI, RVI increased with an increase in Leaf Area Index till 5.8 even during panicle initiation stage. Backscatter and truncated RVI almost follow a similar trend of RVI response for various crop growth parameters. Hence, in case of regional analysis and high cost of Radarsat-2 dataset, one can use freely available sentinel data for RVI analysis due to its wider swath coverage. The observed high correlation of crop age with RVI (R2 = 0.6) proved to be the best tool for predicting sowing dates in staggered sowing zones.

Association of Breast Cancer with Sleep Pattern - A Pilot Case Control Study in a Regional Cancer Centre in South Asia

Datta, Karabi,Roy, Asoke,Nanda, Durgaprasad,Das, Ila,Guha, Subhas,Ghosh, Dipanwita,Sikdar, Samar,Biswas, Jaydip Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.20

The rising trend of breast cancer both in developed and developing countries is a real threat challenging all efforts to screening, prevention and treatment aspects to reduce its impact. In spite of modern preventive strategies, the upward trend of breast cancer has become a matter of great concern in both developed and developing countries. Chittaranjan National Cancer Institute is a premier regional cancer institute in eastern region of India catering to a large number of cancer patients every year. A pilot case control study of fifty breast cancer patients and 100 matched controls was conducted during 2013 to evaluate the effects of habitual factors like working in night shift, not having adequate sleep, and not sleeping in total darkness on breast cancer of women. The study revealed that not sleeping in total darkness was associated with higher odds of outcome of breast cancer of women. This positive correlation can play a vital role in formulation of preventive strategies through life style modification.

Room Temperature Synthesis of Perovskite Hydroxide, MnSn(OH)6: A Negative Electrode for Supercapacitor

Manas Mandal,Krishna Chattopadhyay,Malay Chakraborty,Wonjae Shin,Kamal Kanti Bera,Sujit Chatterjee,Akbar Hossain,Dipanwita Majumdar,Arup Gayen,Changwoon Nah,Swapan Kumar Bhattacharya 대한금속·재료학회 2022 ELECTRONIC MATERIALS LETTERS Vol.18 No.6

A negative electrode is constructed based on MnSn(OH)6 nanocubes prepared by a simple precipitation method at roomtemperature for supercapacitor application. The as-prepared material was structurally and morphologically characterizedwith the help of XRD, FT-IR, Raman, XPS, FESEM, and HRTEM analyses. The uniform structure and fine edge morphologywith high conductivity due to oxygen vacancies promote the redox reaction, which results in high pseudocapacitance. Theelectrochemical performance is investigated through a three-electrode cell system in a negative potential window (− 1.0 to0.0 V). A maximum specific capacitance of 209 F/g is calculated at a specific current of 1 A/g. The electrodes also exhibitexcellent cycling stability (79% specific capacitance retention after 3000 consecutive GCD cycles).