An exponentially fitted finite difference scheme for a class of singularly perturbed delay differential equations with large delays

AbstractThis paper deals with singularly perturbed boundary value problem for a linear second order delay differential equation. It is known that the classical numerical methods are not satisfactory when applied to solve singularly perturbed problems in delay differential equations. In this paper we present an exponentially fitted finite difference scheme to overcome the drawbacks of the corresponding classical counter parts. The stability of the scheme is investigated. The proposed scheme is analyzed for convergence. Several linear singularly perturbed delay differential equations have been solved and the numerical results are presented to support the theory

GPU-based 3D iceball modeling for fast cryoablation simulation and planning

Purpose The elimination of abdominal tumors by percutaneous cryoablation has been shown to be an effective and less invasive alternative to open surgery. Cryoablation destroys malignant cells by freezing them with one or more cryoprobes inserted into the tumor through the skin. Alternating cycles of freezing and thawing produce an enveloping iceball that causes the tumor necrosis. Planning such a procedure is difficult and time-consuming, as it is necessary to plan the number and cryoprobe locations and predict the iceball shape which is also influenced by the presence of heating sources, e.g., major blood vessels and warm saline solution, injected to protect surrounding structures from the cold. Methods This paper describes a method for fast GPU-based iceball modeling based on the simulation of thermal propagation in the tissue. Our algorithm solves the heat equation within a cube around the cryoprobes tips and accounts for the presence of heating sources around the iceball. Results Experimental results of two studies have been obtained: an ex vivo warm gel setup and simulation on five retrospective patient cases of kidney tumors cryoablation with various levels of complexity of the vascular structure and warm saline solution around the tumor tissue. The experiments have been conducted in various conditions of cube size and algorithm implementations. Results show that it is possible to obtain an accurate result within seconds. Conclusion The promising results indicate that our method yields accurate iceball shape predictions in a short time and is suitable for surgical planning

Impact of farmer producer organization on organic chilli production in Telangana, India

33-43Input intensive modern agriculture is adversely affecting human health and environment. Farmers of Telangana state have taken up organic chilli production with the assistance of FPOs. Primary data was collected from 120 farmers comprising 60 members and 60 non-members of FPO from two districts of Telangana through semi-structured interviews. The study found that the shift to organic chilli cultivation led to decrease in input use by 9.06% and yield by 23.4%. However, the gross return from organic chilli farming was 13.85% higher over that realised by non-members due to the efforts of FPOs. DEA analysis revealed that a higher proportion of member farmers (48%) had technical efficiency of more than 60% as compared to non-members (18%). FPOs were instrumental in reduction of transaction cost and number of intermediaries leading to the realization of a higher proportion of producer’s share in consumer’s rupee (65%). Discriminant function analysis revealed that the FPO promoting institutions (44%), ease of doing business (16%) and infrastructure facilities like storage, irrigation, electricity and credit have high influence on performance of the states with respect to FPOs

Celebration-induced air quality over a tropical urban station, Pune, India

AbstractIn this paper, we studied the regional aerosol and air quality over an urban location, Pune, India during the period from 8 to 18 November 2012, encompassing a major Indian celebration, namely, Diwali Festival (12–14 November 2012) and also a clean (control) day (9 November 2012). A suit of ground–based measurements, employing solar radiometers (Microtops II and Cimel Sun–sky radiometer), Nephelometer, and satellite observations carried out over the study region have been applied for these investigations. The study revealed many interesting results which include (i) almost four–fold enhancement in AOD and fine mode dominated aerosol size distribution (ASD) during Diwali compared to clean day conditions; (ii) higher columnar water vapor (H2O), nitrogen dioxide (NO2), and lower ozone (O3) during Diwali period; (iii) higher cooling at bottom (–117W m−2) and top of the atmosphere (–33W m−2) and warming (+82W m−2) in the atmosphere during the festival period, (iv) abundance of fine mode anthropogenic scattering particles associated with greater real part and smaller imaginary part of refractive index, and higher single scattering albedo, (v) higher backscattering coefficient revealing intrusion of more aerosol particles, higher depolarization ratio indicating particles of non–spherical nature, presence of water–phase particles, more polluted smoke and dust particles, (vi) greater attenuation and poor horizontal/vertical visibility, and (vii) dominance of urban industrial/biomass burning aerosols among other aerosol types. These results have been compared with concurrent satellite products and found to be consistent. The results have been further explained with local meteorology, back–trajectory analysis and satellite rapid response images

A numerical scheme for singularly perturbed delay differential equations of convection-diffusion type on an adaptive grid

In this paper, an adaptive mesh strategy is presented for solving singularly perturbed delay differential equation of convection-diffusion type using second order central finite difference scheme. Layer adaptive meshes are generated via an entropy production operator. The details of the location and width of the layer is not required in the proposed method unlike the popular layer adaptive meshes mainly by Bakhvalov and Shishkin. An extensive amount of computational work has been carried out to demonstrate the applicability of the proposed method

Impact of farmer producer organization on organic chilli production in Telangana, India

Input intensive modern agriculture is adversely affecting human health and environment. Farmers of Telangana state have taken up organic chilli production with the assistance of FPOs. Primary data was collected from 120 farmers comprising 60 members and 60 non-members of FPO from two districts of Telangana through semi-structured interviews. The study found that the shift to organic chilli cultivation led to decrease in input use by 9.06% and yield by 23.4%. However, the gross return from organic chilli farming was 13.85% higher over that realised by non-members due to the efforts of FPOs. DEA analysis revealed that a higher proportion of member farmers (48%) had technical efficiency of more than 60% as compared to non-members (18%). FPOs were instrumental in reduction of transaction cost and number of intermediaries leading to the realization of a higher proportion of producer’s share in consumer’s rupee (65%). Discriminant function analysis revealed that the FPO promoting institutions (44%), ease of doing business (16%) and infrastructure facilities like storage, irrigation, electricity and credit have high influence on performance of the states with respect to FPOs

Preclinical evaluation of the atraumatic nature of a spring loaded blunt tip coaxial needle in a swine model

International audiencePurpose: To test in vivo in an animal model the inherent atraumatic characteristics of the spring loaded blunt tip of a coaxial needle (Gangi-SoftGuard®, Apriomed, Sweden) against a conventional sharp stylet coaxial needle.Material and Methods: The study was conducted on a 40 kg male swine that was its own control for a vascular trauma model. The procedure consisted of voluntary attempts to transfix and traverse the artery/aorta under continuous real-time angiogram. Test and control needles were positioned in the region of the intercostal, superior mesenteric and femoral/deep femoral arteries, and in the aorta. Computed tomography (CT) angiogram was performed post trauma to check for bleeding in the form of extravasation of contrast material. One attempt was performed per site and needle, except for the intercostal artery where a second attempt was done with the test needle, resulting in a total of 4 and 5 tests for the control and test needles, respectively.Results: With the spring loaded blunt tip, no vascular trauma or bleeding was noted in the intercostal, superior mesenteric and femoral arteries, nor in the aorta. Vascular spasm that recovered with time was noted during the second attempt to transfix the same intercostal artery. There were consistent vascular traumas and bleedings with the control needle in all three tested arteries and the aorta, confirmed on angiogram as well as CT angiogram.Conclusion: The atraumatic feature offered by the spring loaded blunt tip prevented vascular trauma during the 5 attempts made to transfix the artery/aorta in a swin

Chemical composition and isotopic signatures of ice and snow over a Himalayan Glacier (Satopanth) in India

This study reports the chemical composition and isotopic signatures of snow and ice over a Himalayan Glacier in India. An observational campaign was carried out from September 22, 2016, to October 2, 2016, over Satopanth in central Himalaya. The pH value of ice and snow, respectively, was 5.6 ± 0.4 and 5.9 ± 0.35 over the glacier, indicating moderate acidity of the glacier components. Calcium (Ca2+) was the dominant component in snow (35.2%), while sulfate (SO42−) was dominant in ice samples (52.7%). The neutralization factor was estimated to find the extent of neutralization of acidic fractions by basic components. It is found that Ca2+ was the prominent neutralizing factor both in snow and ice over the region. Oxygen and hydrogen isotopic analyses of snow, surface layer ice and debris-covered ice suggest that the moisture source is common for all three components. δD and d-excess values of snow at Satopanth are different than that of those for Chorabari, Dokriani and Tiprabank Glacier, indicating the plausibility of different sources of moisture for these glaciers. Limited observations suggest that the interaction of ice with the debris has no impact on the isotopic signatures of the ice over the region; such non-alteration of isotopic signatures makes the region important for ice core-based paleoclimatic studies

Captive breeding of a near threatened fish, pengba Osteobrama belangeri (Valenciennes, 1844) using three different inducing agents

Farm reared pengba, Osteobrama belangeri were induced to spawn in captivity during August, 2012 by injecting three different synthetic hormones, Ovaprim, Ovatide and Gonopro-FH. Single dose (1 ml kg-1 body weight) of each hormone was administered and results were recorded. Spawning was observed within 8 h after injection. Hatching of eggs were observed after 22±2 h of incubation at 27±1OC. The mean fertilization rate was 84.05±0.36% for Ovaprim, 79.17±3.95% for Ovatide and 84.85±0.89% for Gonopro-FH treated fish. The mean hatching rate was 84.69±1.73% with Ovaprim, 75.01±1.92% with Ovatide and 86.52±0.88% with Gonopro-FH. Gonopro-FH and Ovaprim gave 5.67 and 4.88% higher fertilization rate as well as 11.5 and 9.69% more hatching rate of eggs respectively as compared to Ovatide. Ovaprim and Gonopro-FH were found to be more effective in induced breeding of O. belangeri