Maximizing the Number of Spatial Nulls with Minimum Sensors

In this paper, we attempt to unify two array processing frameworks viz, Acoustic Vector Sensor (AVS) and two level nested array to enhance the Degrees of Freedom (DoF) significantly beyond the limit that is attained by a Uniform Linear Hydrophone Array (ULA) with specified number of sensors. The major focus is to design a line array architecture which provides high resolution unambiguous bearing estimation with increased number of spatial nulls to mitigate the multiple interferences in a deep ocean scenario. AVS can provide more information about the propagating acoustic field intensity vector by simultaneously measuring the acoustic pressure along with tri-axial particle velocity components. In this work, we have developed Nested AVS array (NAVS) ocean data model to demonstrate the performance enhancement. Conventional and MVDR spatial filters are used as the response function to evaluate the performance of the proposed architecture. Simulation results show significant improvement in performance viz, increase of DoF, and localization of more number of acoustic sources and high resolution bearing estimation with reduced side lobe level

Ethylene-propylene Diene Rubber as a Futuristic Elastomer for Insulation of Solid Rocket Motors

The study carried out so far on the application of ethylene-propylene diene rubber (EPDM)in the field of insulation of case bonded solid rocket motors has been reviewed. The variousstudies by the authors (unpublished work) have also been reported. All these findings bring outthe excellent potential of EPDM as insulator in view of its ageing resistance, low-temperatureflexibility, low erosion rate, and low specific gravity

Social Determinants of Health and Distance Learning in Italy in the Era of the SARS-CoV-2 Pandemic

Objectives: To investigate the experiences by distance learning (DL) method during the first wave of the SARS-CoV-2 pandemic in Italy, and to search for correlations with purported experiences and respective levels of social determinants of health (SDH). Study design and methods: Cross-sectional online survey, investigating various SDH and parents’ attitude towards DL, proposed 6 months after the beginning of the pandemic to a sample population of parents with school-aged children throughout Italy. Results: A total of 3791 questionnaires were analyzed. Non-Italian parents complained more frequently of difficulties in providing support to their children in DL due to poor digital skills (p = 0.01), lack of good-quality digital equipment (p = 0.01), problems with the Italian language (p < 0.001), and a lower level of education (p < 0.001). When parents lived apart, greater difficulties in concentration in children using DL (p = 0.05) and a lower parental capacity to support DL (p = 0.002) were reported. Adequate digital structures appeared related to living in owned compared to rented property, higher levels of parental education, and better familial financial situations. Conclusions: Students from families with financial difficulties and low levels of parental education, or even those living in houses for rent or having separated parents, may be disadvantaged in an educational context since the introduction of DL

CURRENT STATUS OF AMBEWELA RESERVOIR OF SRI LANKA WITH SPECIALREFERENCE TO WATER POLLUTION

The water pollution trends in the Ambewela reservoir at the uppermost catchment of Kotmale River was assessed through a study on chemical and bio monitoring programme that carried out from March to October 2008.The mean average value (mean ± SD) of the nitrate, nitrite, phosphate and ammonia concentrations in Ambewela reservoir were 0.780 ± 1.386 mg/l, 0.103 ± 0.223mg/l, 0.051 ± 0.061mg/l and 0.218± 0.261 mg/l whereas values for the streams selected from Dambagasthalawa Oya were 0.985 ± 0.902 mg/l, 0.099  ± 0.207mg/l, 0.038 ± 0.026 mg/l and 0.085± 0.077 mg/l respectively. Average Chlorophyll- a values of the reservoir were 17.85 ± 17.858 mg/m3 and 8.30 ± 4.686 mg/m3for other two streams accordingly. Average BOD values of the reservoir were 8.06 ± 3.494 and 4.25 ± 2.251 for other two streams correspondingly.The bio monitoring studies also clearly showed sudden records of huge colonies of  Hydra(approximately 258/cm3) in the reservoir from time to time. This phenomenon was found in relatively dry period that directly coincided with intensified use of agro chemicals. Moreover, steady population of Chironomid (average population density 208/cm3) that is commonly accepted pollution indicator was reported at Ambewela reservoir throughout the study period.Therefore, both chemical and bio monitoring studies indicate eutrophic condition in Ambewela reservoir in which long run might affect on the ecology of the entire ecosystem. Hence prompt mitigatory action should be implemented to avoid further depletion.Key Words: Ambewela Reservoir, Water Pollution, Physico-Chemical Parameters, Chlorophyll –

Galaxy and Mass Assembly (GAMA): Mid-infrared properties as tracers of galaxy environment

We investigate how different mid-infrared (mid-IR) properties of galaxies trace the environment in which the galaxies are located. For this purpose, we first study the dependence of galaxy clustering on the absolute magnitude at 3.4 $\mu$m and redshift. Then, we look into the environmental dependence of mid-IR luminosities and the galaxy properties derived from these luminosities. We also explore how various infrared galaxy luminosity selections influence the galaxy clustering measurements. We use a set of W1 (3.4 $\mu$m) absolute magnitude ($M_\text{W1}$) selected samples from the Galaxy and Mass Assembly (GAMA) survey matched with mid-IR properties from the Wide-field Infrared Survey Explorer (WISE) in the redshift range $0.07 \leq z < 0.43$. We compute the galaxy two-point correlation function (2pCF) and compare the clustering lengths between subsamples binned in $M_\text{W1}$ and in redshift. We also measure the marked correlation functions (MCFs) using the luminosities in the WISE W1 to W4 (3.4 to 22 $\mu$m) bands as marks. Additionally, we compare the measurements of MCFs with different estimates of stellar mass and star formation rate used as marks. Finally, we check how different selections applied to the sample affect the clustering measurements. We show strong clustering dependence on the W1 absolute magnitude: galaxies brighter in the W1 band are more strongly clustered than their fainter counterparts. We also observe a lack of significant redshift dependence of clustering in the redshift range $0.07 \leq z < 0.43$. We show that although W1 and W2 bands are direct indicators of stellar mass, a galaxy sample selected based on W1 or W2 bands does not perfectly show the clustering behaviour of a stellar mass selected sample. Similar is the case with the proxy relation between W3 and W4 bands and star formation rate.Comment: 19 pages, 12 figures, accepted in A&

Stabilization of Hydrodynamic Flows by Small Viscosity Variations

Motivated by the large effect of turbulent drag reduction by minute concentrations of polymers we study the effects of a weakly space-dependent viscosity on the stability of hydrodynamic flows. In a recent Letter [Phys. Rev. Lett. {\bf 87}, 174501, (2001)] we exposed the crucial role played by a localized region where the energy of fluctuations is produced by interactions with the mean flow (the "critical layer"). We showed that a layer of weakly space-dependent viscosity placed near the critical layer can have a very large stabilizing effect on hydrodynamic fluctuations, retarding significantly the onset of turbulence. In this paper we extend these observation in two directions: first we show that the strong stabilization of the primary instability is also obtained when the viscosity profile is realistic (inferred from simulations of turbulent flows with a small concentration of polymers). Second, we analyze the secondary instability (around the time-dependent primary instability) and find similar strong stabilization. Since the secondary instability develops around a time-dependent solution and is three-dimensional, this brings us closer to the turbulent case. We reiterate that the large effect is {\em not} due to a modified dissipation (as is assumed in some theories of drag reduction), but due to reduced energy intake from the mean flow to the fluctuations. We propose that similar physics act in turbulent drag reduction.Comment: 10 pages, 17 figs., REVTeX4, PRE, submitte

Self-similar shear-thickening behavior in CTAB/NaSal surfactant solutions

The effect of salt concentration Cs on the critical shear rate required for the onset of shear thickening and apparent relaxation time of the shear-thickened phase, has been investigated systematically for dilute CTAB/NaSal solutions. Experimental data suggest a self-similar behavior of the critical shear rate and relaxation time as functions of Cs. Specifically, the former ~ Cs^(-6) whereas the latter ~ Cs^(6) such that an effective Weissenberg number for the onset of the shear thickened phase is only weakly dependent on Cs. A procedure has been developed to collapse the apparent shear viscosity versus shear rate data obtained for various values of Cs into a single master curve. The effect of Cs on the elastic modulus and mesh size of the shear-induced gel phase for different surfactant concentrations is discussed. Experiments performed using different flow cells (Couette and cone-and-plate) show that the critical shear rate, relaxation time and the maximum viscosity attained are geometry-independent. The elastic modulus of the gel phase inferred indirectly by employing simplified hydrodynamic instability analysis of a sheared gel-fluid interface is in qualitative agreement with that predicted for an entangled phase of living polymers. A qualitative mechanism that combines the effect of Cs on average micelle length and Debye parameter with shear-induced configurational changes of rod-like micelles is proposed to rationalize the self-similarity of SIS formation.Comment: 27 pages, 17 figure

STUDY THE EFFECT OF SALINITY AND NUTRIENTS FOR THE GROWTH OF Najas marina AND ITS IMPACT TO AQUATIC BIODIVERSITY IN MADU GANGA RAMSAR WETLAND IN SRI LANKA

Madu Ganga is the latest addition to the Ramsar International Convention of Wetlands. Najas marinais an alien aquatic plant and 0.5 m long that are often branched toward the upward portion of the plant. The objective of the study was to study the impact of salinity and nutrients for the growth of Najas marina. Samples were collected for analysed water quality parameters from March, 2006 to January 2007 in the lagoon. Mapping was done using Garmin GPS map 76CS and Arc GIS used to developed maps.Mean nutrient such as, nitrate nitrogen, ammonia nitrogen and orthophosphate concentrations were observed 0.26 ± 0.3 mg/l, 0.057 ± 0.04 mg/l, and 0.354 ± 0.77 mg/l subsequently. Mean salinity variation in bottom and surface are 6.38 ± 6.65 ppt and 4.31 ±  4.68 ppt. Higher bottom salinity was observed in location number 02 (near to sea mouth) and  Najas marinawas not present in the area. Najas marina was also not recorded in upper part of the lagoon and fresh water streams studied. High density of Najas marina plants were observed in sampling location 07, 08 and 09, because of the high nutrient concentration flowing through feeding tributaries. More than 25 % of lagoon area was covered by Najas marina.

Systematic review on barriers and enablers for access to diabetic retinopathy screening services in different income settings.

BackgroundDiabetic retinopathy (DR) can lead to visual impairment and blindness if not detected and treated in time. Knowing the barriers/enablers in advance in contrasting different country income settings may accelerate development of a successful DR screening (DRS) program. This would be especially applicable in the low-income settings with the rising prevalence of DR.ObjectivesThe aim of this systematic review is to identify and contrast the barriers/enablers to DRS for different contexts using both consumers i.e., people with diabetes (PwDM) and provider perspectives and system level factors in different country income settings.MethodsWe searched MEDLINE, Embase, CENTRAL in the Cochrane Library from the databases start date to December 2018. We included the studies reported on barriers and enablers to access DRS services based at health care facilities. We categorised and synthesized themes related to the consumers (individuals), providers and the health systems (environment) as main dimensions according to the constructs of social cognitive theory, supported by the quantitative measures i.e., odds ratios as reported by each of the study authors.Main resultsWe included 77 studies primarily describing the barriers and enablers. Most of the studies were from high income settings (72.7, 56/77) and cross sectional in design (76.6, 59/77). From the perspectives of consumers, lack of knowledge, attitude, awareness and motivation were identified as major barriers. The enablers were fear of blindness, proximity of screening facility, experiences of vision loss and being concerned of eye complications. In providers’ perspectives, lack of skilled human resources, training programs, infrastructure of retinal imaging and cost of services were the main barriers. Higher odds of uptake of DRS services was observed when PwDM were provided health education (odds ratio (OR) 4.3) and having knowledge on DR (OR range 1.3–19.7).ConclusionKnowing the barriers to access DRS is a pre-requisite in development of a successful screening program. The awareness, knowledge and attitude of the consumers, availability of skilled human resources and infrastructure emerged as the major barriers to access to DRS in any income setting

Beneficial health effects of cumin (Cuminum cyminum) seeds upon incorporation as a potential feed additive in livestock and poultry: A mini-review

Cumin (Cuminum cyminum Linn) is an annual plant of the family Umbelliferae, with its use dating back to ancient times when it was cultivated for its medicinal and culinary potential. Cumin seeds could contain a wide variety of phytochemicals, including alkaloids, coumarins, anthraquinones, flavonoids, glycosides, proteins, resins, saponins, tannins, and steroids. In particular, linoleic acid, one of the unsaturated fatty acids found in abundance in cumin oleoresin, is credited with promoting good health. Many of cumin's purported biological actions in livestock and poultry have been attributed to flavonoids such as apigenin, luteolin, and glycosides. Cumin has several healthful qualities, such as antibacterial, insecticidal, anti-inflammatory, analgesic, antioxidant, anticancer, anti-diabetic, anti-platelet aggregation, hypotensive, bronchodilatory, immunological, anti-amyloidogenic, and anti-osteoporotic properties. Cumin supplementation may improve milk production and reproductive function in dairy cows by altering the feeding pattern of bacteria in the rumen, encouraging the growth of beneficial microbes, or stimulating the secretion of certain digestive enzymes. Because of the low price of cumin seed, it could be concluded that its inclusion in the diet might be beneficial to the commercial poultry industry and reduce the overall cost of egg and meat production. In recent years a rise in cumin's popularity has been seen as a result of the herbal movement spearheaded by naturopaths, yoga gurus, advocates of alternative medicine, and manufacturers of feed additives. Animal nutritionists are exploring the use of cumin for its potential to boost growth, improve nutrient usage efficiency, and reduce greenhouse gas emissions. This mini-review discusses how cumin could be used as a feed ingredient to boost productivity and ensure healthy animal reproduction