Design and Modelling of a Two-port Surface Acoustic WaveResonator using Coupling-of-modes Theory

In this present paper the coupling-of-modes theory has been used to design and simulatethe characteristics of a two-port SAW resonator with shorted reflection gratings to define theresonance cavity. A resonator device at 150 MHz has been designed and fabricated on ST-Quartz. It is found that the simulated and experimental characteristics of the device are in closeagreement. The results show that the SAW designs based on coupling-of-modes formulationare adequate for most applications

Larvicidal and mosquito repellent activities of Pine (Pinus longifolia, Family: Pinaceae) oil

Background & objectives: Various plant-based products are safe and biodegradable alternatives tosynthetic chemicals for use against mosquitoes. Oil of Pinus longifolia is traditionally used forprotection against mosquitoes in some rural areas but there is no documented report of its use againstmosquitoes. The present study was undertaken to scientifically evaluate the activity of Pine oilagainst mosquitoes.Methods: The oil was procured from the market and its contents were chemically analysed. Larvicidalactivity of oil was tested in laboratory bioassays, while repellent action was studied during wholenight bait collections in field by direct application on the skin and after its impregnation on mats.Results: Results showed varying degree of larvicidal activity of Pine oil against mosquitoes with LC50values ranging between 82 and 112 ppm. The Pine oil had strong repellent action against mosquitoesas it provided 100% protection against Anopheles culicifacies for 11 h and 97% protection againstCulex quinquefasciatus for nine hours respectively. Electrically heated mats prepared from Pine oilprovided, 94 and 88% protection against An. culicifacies and Cx. quinquefasciatus for 10 and sevenhours respectively.Interpretaion & conclusion: Pine oil is effective against mosquito larvae at very higher doses whichare not of any practical utility. However, Pine oil showed strong repellent action against An. culicifacies(malaria vector) and Cx. quinquefasciatus (pest mosquito). Thus its use could be popularised asmosquito repellent

Some socio-economic aspects of the fishermen of twin pronged floodplain wetlands in West Bengal

A socio-economic investigation was carried out in two fishermen cooperative societies namely Purba Helatala Fishermen Co-operative Society (E-1), Barhal Fishermen Co-operative Society (E-2), under Maldah district, West Bengal to which the beels (flood plains) under study belong. A total of 132 member fishermen, which constituted the sample, were personally interviewed. The age group of the fishermen of the sample in E-1 varied between 20 and 66 years whereas in E-2 it was 22 and 61 years. All the members of the sample belonged to Scheduled Caste (SC) community. The primary occupation of all the respondents of both the beels was observed to be fishing (100%). Maximum number of illiterate respondents was observed to 56% in E-2 and 35% in E-1. It has been observed that as many as 38.3% of fishermen were having fishing experience which ranging from 16 to 20 years in E-1 whereas it was 6 - 10 years (36.1%) in E-2. Maximum number of fishermen lived in thatched houses (41.66%) in E-1 whereas in E-2 most of them lived in houses made of corrugated tin/tile shed (41.66%). As many as 41.55% of E-1 and 30.55% of E-2 used dug-out canoes for their fishing. Maximum number of fishermen used cast net with individualistic approach (100%) followed by Gill net (E-1:41.56% and E-2:55.55%). Most of the fishermen of the sample participated in fishing activities for 241 to 270 days (41.66%) in E-2 whereas it was 211 to 240 days (33.33 %) in E-1 in a year. During fishing season as many as 40.0% of the respondents of E-1 earned on an average Rs. 801.00 to Rs. 900.00 per month whereas it was Rs. 901.00 to Rs.1,000.00 (43.05%) in case of E-2. A section of fishermen of the sample borrowed money often (51.6%) E-1 whereas it was most often (27.27%) of E-2. The respondents of E-2 made regular repayment of the loan to the maximum extent (79.48%) whereas it was 57.44% in E-1. Higher fish production vis-a-vis higher income for the fishermen was observed in the beel (E2) having close characteristic

Evaluation of the impact of ZeroFly® , an insecticide incorporated plastic sheeting on malaria incidence in two temporary labour shelters in India

Background & objectives: Prevention of malaria is a major technical and operational problem in displaced andmobile populations such as refugee camps and temporary labour settlements. Insecticide incorporated plasticsheeting is a new technology to control mosquitoes in emergency shelters and also temporary habitations atdifferent locations. In view of this, efficacy of ZeroFly®, an insecticide incorporated plastic sheeting (factorytreated with deltamethrin 2.0 g/kg or 265 mg/m2) was evaluated for its efficacy against malaria vectors and itsimpact on malaria incidence in temporary labour settlements in two urban areas in India.Methods: This trial was conducted in two labour settlements in two urban areas, Delhi and Noida (U.P.), Indiawith ~ 250 populations. In an area, two localities were selected for intervention with ZeroFly and untreatedplastic sheets (control). Entomological and epidemiological data were collected using standard methods for one year.Results: Baseline studies on the susceptibility of mosquitoes in Delhi and Noida areas revealed 100% susceptibilityof the malaria vector species Anopheles culicifacies and An. stephensi to deltamethrin. Cone bioassay testsperformed against An. culicifacies and An. stephensi to determine the efficacy of ZeroFly sheets showed 100%mortality against An. culicifacies and An. stephensi with 3 min exposure and after 24 h recovery period. AgainstCulex quinquefasciatus and housefly 100% mortality was obtained after 30 min of exposure period. Interventionwith the ZeroFly plastic sheets resulted in almost complete reduction in the resting density of An. culicifaciesand An. stephensi, the two major malaria vectors and also in the reduction of malaria cases in ZeroFly camps ascompared to control camps. The ZeroFly plastic sheeting was found to be safe for human. Barring some complaintsof skin irritation and itching, which were temporary in nature, no adverse health effects were reported by theusers. The community acceptance was high.Conclusion: Results of the present study revealed that ZeroFly® plastic sheeting is highly effective in reducingthe indoor resting density of mosquitoes, man-vector contact and malaria incidences in labour populations livingin temporary shelters

Safety and efficacy of dialyzer reuse by manual reprocessing: an observational study

Background: Haemodialysis is the main form of RRT in the patients of CKD. Haemodialysis is a costly procedure and is not afforded by many. Reuse of components of Haemodialysis circuit helps in reducing cost but may be associated with decreased efficacy and side effects.Methods: Prospective observational study. Manual reprocessing of dialyzer was done with either formaldehyde or peracetic acid. Single brand (Fresenius) dialyzer were used across all patients. Dialysis efficacy was calculated by URR and side effect and toxicity monitored in a predefined proforma.Results: A total 50 patients were studied (39 male and 11 female) with age ranging from 31-60 years. The mean urea reduction ratio after four dialysis session with the same dialyzer was 62.93% which is below KDOQI recommendation. The findings in our study suggest that URR was adequate upto three session of haemodialysis by reprocessed dialyzer but not beyond that. The choice of chemical for reprocessing did not affect the efficacy. As compared to F6 dialyze F8 dialyzer had better initial URR and this was maintained upto fourth reuse. Serum albumin levels correlated with the fall in efficacy of dialyzers. There were no significant complications of reuse of dialyzers across both methods of reprocessing and there was no dialyzer first use syndrome.Conclusions: ESRD affects a younger age group in our country. Use of large membrane area results in better efficacy. Dialyzer reuse with manual reprocessing is safe and also effective upto third and fourth use. Dialyzer reuse is associated with economic benefits

Bifurcations in the wake of a thick circular disk

Using DNS, we investigate the dynamics in the wake of a circular disk of aspect ratio χ = d/w = 3(where d is the diameter and w the thickness) embedded in a uniform flow of magnitude U0 perpendicular to its symmetry axis. As the Reynolds number Re = U0d/ν is increased, the flow is shown to experience an original series of bifurcations leading to chaos. The range Re ∈ [150, 218] is analysed in detail. In this range, five different non-axisymmetric regimes are successively encountered, including states similar to those previously identified in the flow past a sphere or an infinitely thin disk, as well as a new regime characterised by the presence of two distinct frequencies. A theoretical model based on the theory of mode interaction with symmetries, previously introduced to explain the bifurcations in the flow past a sphere or an infinitely thin disk (Fabre et al. in Phys Fluids 20:051702, 2008), is shown to explain correctly all these results. Higher values of the Reynolds number, up to 270, are also considered. Results indicate that the flow encounters at least four additional bifurcations before reaching a chaotic state