OALib Journal期刊

ISSN: 2333-9721



匹配条件: “Rachana Pathak” ,找到相关结果约767条。
Conservation of Forestry Biomass with the Use of Alternative Resource  [PDF]
Manju Agarwal, Rachana Pathak
Open Journal of Ecology (OJE) , 2015, DOI: 10.4236/oje.2015.54009
Abstract: The effect of the alternative resource and time delay on conservation of forestry biomass is studied by considering a nonlinear mathematical model. In this paper, interaction between forestry biomass, industrialization pressure, toxicant pressure and technological effort is proposed and analysed. We find out the critical value of delay and observe that there is Hopf bifurcation. Using the normal form theory and the center manifold theorem, we determine the stability and direction of the bifurcating periodic solutions. Numerical simulations are given to illustrate the analytical results.
Depletion of Forest Resources and Wildlife Population with Habitat Complexity: A Mathematical Model  [PDF]
Rachana Pathak
Open Journal of Ecology (OJE) , 2018, DOI: 10.4236/oje.2018.811034
Abstract: Nowadays, management and regulation of natural resources like agriculture, fisheries, forestry and wildlife is one of the popular topics in research. The evolution of humankind is largely dependent on the quality of the environment and the resources it provides; but numerous human-induced factors, and climate change may drastically alter the conditions of human sustainability. This paper deals with effect of numerous human-induced activities on the depletion of forestry resources and wildlife population with habitat complexity. A nonlinear mathematical model is proposed and analyzed. In modeling process, we assume that the growth rate of wildlife population wholly depends on forestry biomass. It is depleted by human-induced activities. Local stability analysis of the mathematical model along with the persistence of the system is checked by using theory of nonlinear ordinary differential equations and Butler-McGhee lemma. Analytical results obtained are justified numerically through numerical simulation. Important parameters are investigated and variation of variables with change in these parameters is determined.
Harvesting and Hopf Bifurcation in a prey-predator model with Holling Type IV Functional Response
Manju Agarwal,Rachana Pathak
International Journal of Mathematics and Soft Computing , 2012,
Abstract: This paper aims to study the effect of Harvesting on predator species with time-delay on a Holling type-IV prey-predator model. Harvesting has a strong impact on the dynamic evolution of a population. Two delays are considered in the model of this paper to describe the time that juveniles of prey and predator take to mature. Dynamics of the system is studied in terms of local and Hopf bifurcation analysis. Finally, numerical simulation is done to support the analytical findings.
Harvesting, Hopf Bifurcation and Chaos in Three Species Food Chain Model with Beddington–DeAngelis Type Functional Response
Manju Agarwal,Rachana Pathak
Journal of Global Research in Mathematical Archives , 2013,
Abstract: The dynamical relationship between predator and prey can be represented by the prey functional response which refers to the change in the density of prey attached per unit time per predator as the prey density changes. In this paper, three-species food chain model with Beddington–DeAngelis type functional response is considered and found solution both analytically and numerically. We investigate the Hopf bifurcation and Chaos of the system at mortality rate ( ) of predator with the help of computer simulations. Butler-Mc Gehee lemma is used to identify the condition which influences the persistence of the system. We also study the effect of Harvesting on prey species. Harvesting has a strong impact on the dynamic evolution of a population. To a certain extent, it can control the long-term stationary density of population efficiently. However, it can also lead to the incorporation of a positive extinction probability and therefore to potential extinction in finite time. Our result suggests that the mortality rate of predator species have the ability to control the chaotic dynamics. Keywords: Food Chain Model, Stability, Persistence,Harvesting, Chaotic Attractor, Hopf Bifurcation
A candidate multimodal functional genetic network for thermal adaptation
Katharina C. Wollenberg Valero,Rachana Pathak,Indira Prajapati,Shannon Bankston,Aprylle Thompson,Jaytriece Usher,Raphael D. Isokpehi
PeerJ , 2015, DOI: 10.7717/peerj.578
Abstract: Vertebrate ectotherms such as reptiles provide ideal organisms for the study of adaptation to environmental thermal change. Comparative genomic and exomic studies can recover markers that diverge between warm and cold adapted lineages, but the genes that are functionally related to thermal adaptation may be difficult to identify. We here used a bioinformatics genome-mining approach to predict and identify functions for suitable candidate markers for thermal adaptation in the chicken. We first established a framework of candidate functions for such markers, and then compiled the literature on genes known to adapt to the thermal environment in different lineages of vertebrates. We then identified them in the genomes of human, chicken, and the lizard Anolis carolinensis, and established a functional genetic interaction network in the chicken. Surprisingly, markers initially identified from diverse lineages of vertebrates such as human and fish were all in close functional relationship with each other and more associated than expected by chance. This indicates that the general genetic functional network for thermoregulation and/or thermal adaptation to the environment might be regulated via similar evolutionarily conserved pathways in different vertebrate lineages. We were able to identify seven functions that were statistically overrepresented in this network, corresponding to four of our originally predicted functions plus three unpredicted functions. We describe this network as multimodal: central regulator genes with the function of relaying thermal signal (1), affect genes with different cellular functions, namely (2) lipoprotein metabolism, (3) membrane channels, (4) stress response, (5) response to oxidative stress, (6) muscle contraction and relaxation, and (7) vasodilation, vasoconstriction and regulation of blood pressure. This network constitutes a novel resource for the study of thermal adaptation in the closely related nonavian reptiles and other vertebrate ectotherms.
Enabling Access to Welfare Services - the Place of Social Solidarity and Dialogue
Patni, Rachana
Social Work and Society , 2007,
Abstract: The welfare state in the UK presents immigrant communities with a set of institutions, which are potentially new and unknown. What is the best way to ensure that the questions of access to the welfare institutions are best managed? Trusting, understanding and feeling solidarity with the welfare state will obviously help with this problem. In order to shed light on this phenomenon, this paper presents a qualitative exploratory study dealing with elements of solidarity as perceived by members of the South Asian Community in the UK. Six indepth interviews with South Asian first generation immigrants who had never experienced mental health problems were conducted. They were asked questions about who their support networks would be in the event of them experiencing mental health problems. The thematic analysis of the interviews suggests that the respondents believed that solidarity and support ties are found to be present in families, within the south Asian community and also with welfare institutions. It is concluded that there although things are far from perfect, assimilation and integration based on dialogue is an observable positive aspect of mental health service provision in the UK.
Non-Communicating inactive rudimentary horn of the uterus presenting with dysmenorrhoea—a case report of successful laparoscopic excision  [PDF]
Rachana Dwivedi, Keerthi Perera, Padma Eedarapalli
Open Journal of Obstetrics and Gynecology (OJOG) , 2011, DOI: 10.4236/ojog.2011.14041
Abstract: Uterine developmental abnormalities can cause both obstetric and gynaecological complications. Non-functioning rudimentary uterine horn is a rare cause of dysmenorrhoea which usually starts after menarche. Cases with lateral/inferior arrangement of blood supply to the functioning rudimentary horn and lapascopic removal have been described in literature. Ours is a unique case of non-functioning rudimentary horn with an unusual medial arrangement of vasculature successfully treated by laparoscopic excision. We also present a brief review of the literature. The patient presented with irretractable dysmenorrhoea despite hormonal manipulation and analgesics. Following the diagnosis using laparoscopy and hysteroscopy and MRI, the left sided non-communicating rudimentary horn with inactive endometrium was removed laparoscopically. Her symptoms were resolved and this was followed by successful pregnancies. Diagnosis of rudimentary horn with inactive endometrium is difficult. Ultrasound is unreliable. MRI, 3D CT scan and 3D ultrasound are gaining popularity. Accurate, prior identification of the type using laparoscopy and hysteroscopy if necessary is essential. This helps in surgical planning. The laparoscopic approach is increasingly being used to resect these horns due to its safety and merits.
Electrochemical, Photophysical, and Magnetic Properties of Green Emitting bis(2,5-Hexyloxy)-Phenylene-alt-Thiophene Fluorescent Conducting Oligomer Addended Fullerene-Diol Dyad  [PDF]
Rachana Singh, Rimpa Jaiswal, Thakohari Goswami
International Journal of Organic Chemistry (IJOC) , 2013, DOI: 10.4236/ijoc.2013.33A006

Towards the development of potential new organic photovoltaic and optoelectronic materials, a simple route to synthesize flexibly ether linked fullerene-bis[oligo-(phenylene-alt-thiophene)] and evaluation of electrochemical, photophysical and magnetic properties is presented. Flexible ether linking of oligo-phenylene-thiophene chain to 1, 2 C60(OH)2 is achieved employing Williamson’s ether synthesis. 7-chain phenylene-thiophene chain fluorescent conducting oligomer is synthesized using Grignard coupling reaction with preservation of bromo end groups. Oligomer is highly ordered and soluble in all organic solvents while on linking to fullerene-diol, solubility of adduct restricts only to dimethyl sulfoxide (DMSO). All the synthesized materials are characterized through spectroscopic techniques and molecular weight is determined by mass spectrometry and GPC. Properties of the material indicate the substantial effect of fullerene. High quenching in fluorescence intensity and strong paramagnetic property are observed in this material.



A Feminist Context In Rokeya Housain's Sultana's Dream
Rachana Vijay Musai
Golden Research Thoughts , 2012, DOI: 10.9780/22315063
Abstract: Rokeya's Sultana's Dream challenges or rather rejects the supremacy of men. She has tried her best to liberate women from the mental condition of 'enslave'. She believes that women will be liberated only when women earn a strong faith on their caliber. The present research paper intends to deal with Rokeya's interpretation of feminism on the background of Sultana's dream.
Wireless Sensor Network MAC Protocol: SMAC & TMAC
Indian Journal of Computer Science and Engineering , 2013,
Abstract: Wireless sensor networks is an emergent technology which has made Ambient Intelligence a reality. It consists of several tiny nodes connected to each other in Ad hoc environment and coordinate with each other to form a network. It has wide range of applications, potential in areas such as intruder alert and tracking, environmental monitoring, industrial process monitoring, and tactical systems.However, as they are spread in areas with difficult terrain and to achieve full coverage of area there are large number of wireless sensors used, it is difficult to replace their batteries once exhausted. Energy conservation is needed especially at MAC layer level. Various MAC protocols with different objectives have been proposed for wireless sensor networks. SMAC is one of the base protocol which with slight modifications results in various protocols. SMAC is having static sleep schedules while TMAC is havingdynamic sleep schedules. In this paper, we first outline the basics of Wireless sensor network then we discuss the properties of MAC layer succeeding with a section outlining the reasons of energy wastes in WSN. Two Protocols discussed in this paper i.e SMAC and TMAC are presented subsequently with their advantages and disadvantages. Finally, before concluding, an article on various design process related to SMAC and TMAC as per WSN is included.

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