Quantitative mapping of rainfall rates over the oceans utilizing Nimbus-5 ESMR data

The electrically scanning microwave radiometer (ESMR) data from the Nimbus 5 satellite was used to deduce estimates of precipitation amount over the oceans. An atlas of the global oceanic rainfall was prepared and the global rainfall maps analyzed and related to available ground truth information as well as to large scale processes in the atmosphere. It was concluded that the ESMR system provides the most reliable and direct approach yet known for the estimation of rainfall over sparsely documented, wide oceanic regions

Periodic variations of precipitation in the tropical Atlantic Ocean

Statistical analysis of the satellite-borne Electrically Scanning Microwave Radiometer data in the tropical Atlantic region reveals that the rainfall near local noon is higher both in frequency of occurrence and intensity than the rainfall in the same area near local midnight. Another striking feature that stands out from the analysis is an oscillation with a period of 3.3. days in rainfall occurrence and intensity. This periodicty is consistent with easterly waves traveling from the African continent to the region under study

New features of global climatology revealed by satellite-derived oceanic rainfall maps

Quantitative rainfall maps over the oceanic areas of the globe were derived from the Nimbus 5 Electrically Scanning Microwave Radiometer (ESMR) data. Analysis of satellite derived oceanic rainfall maps reveal certain distinctive characteristics of global patterns for the years 1973-74. The main ones are (1) the forking of the Intertropical Convergence Zone in the Pacific, (2) a previously unrecognized rain area in the South Atlantic, (3) the bimodal behavior of rainbelts in the Indian Ocean and (4) the large interannual variability in oceanic rainfall. These features are discussed

Do Alternative Therapies Have a Role in Autism?

Interventions considered to be branches of Complementary & Alternative Medicine (CAM) for autism are on the rise. Many new treatments have emerged & traditional beliefs of Ayurveda, Yoga, Behavioral therapy, Speech therapy and Homoeopathy have gained popularity and advocacy among parents. It is imperative that data supporting new treatments should be scrutinized for scientific study design, clinical safety, and scientific validity, before embarking on them as modes of therapy. Practitioners take care in explaining the rationale behind the various approaches that they practice, it is important to indicate possible limitations too during the initial clinical examination and interactive session. Clinicians must remember that parents may have different beliefs regarding the effectiveness of treatment since their information is derived more from the ‘hear-say’ route when they compare benefits/effects of CAM therapies on other children and often underestimate differential tolerance for treatment risks. It is thus significant that practitioners do not assume a "don't ask, don't tell" posture. The scientific validation and support for many interventions is incomplete and very different from the recommendations of the American Academy of Pediatrics Policy Statement. In this article, we discuss the various modes of CAM and their utilities and limitations in relation to autism

Elliptic supersonic jet morphology manipulation using sharp-tipped lobes

Elliptic nozzle geometry is attractive for mixing enhancement of supersonic jets. However, jet dynamics, such as flapping, gives rise to high-intensity tonal sound. We experimentally manipulate the supersonic elliptic jet morphology by using two sharp-tipped lobes. The lobes are placed on either end of the minor axis in an elliptic nozzle. The design Mach number and the aspect ratio of the elliptic nozzle and the lobed nozzle are 2.0 and 1.65. The supersonic jet is exhausted into ambient at almost perfectly expanded conditions. Time-resolved schlieren imaging, longitudinal and cross-sectional planar laser Mie-scattering imaging, planar Particle Image Velocimetry, and near-field microphone measurements are performed to assess the fluidic behavior of the two nozzles. Dynamic Mode and Proper Orthogonal Decomposition (DMD and POD) analysis are carried out on the schlieren and the Mie-scattering images. Mixing characteristics are extracted from the Mie-scattering images through the image processing routines. The flapping elliptic jet consists of two dominant DMD modes, while the lobed nozzle has only one dominant mode, and the flapping is suppressed. Microphone measurements show the associated noise reduction. The jet column bifurcates in the lobed nozzle enabling a larger surface contact area with the ambient fluid and higher mixing rates in the near-field of the nozzle exit. The jet width growth rate of the two-lobed nozzle is about twice as that of the elliptic jet in the near-field, and there is a 40\% reduction in the potential core length. Particle Image Velocimetry (PIV) contours substantiate the results.Comment: 19 pages, 16 figures. Revised version submitted to Physics of Fluids for peer review. URL of the Video files (Fig. 6 & Fig. 14) are given in the text files (see in '/anc/*.txt'

'Slippage' : The Bane of Rural Drinking Water Sector (A Study of Extent and Causes in Andhra Pradesh)

Slippage is one of the main bottlenecks of achieving full coverage of water and sanitation services in India. Slippage is the term often used to reflect unsustainable service delivery of water, sanitation and hygiene (WASH) services, especially in rural areas. Off late slippage is attracting attention at the policy level though slippage is as old as the coverage of water supply services. This paper makes an attempt to identify the causes of slippage in a systematic manner. The broad objectives of the paper include : i) assess the extent of slippage at the national and state level; ii) identify the causes of slippage at various levels; and iii) provide some pointers for policy based on the analysis. The extent of slippage is quite substantial even at the aggregate level. The situation is alarming in some of the states where the extent of slippage is as high as 60 percent. Our analysis at the national, state and habitation levels suggests strongly that policy makers should look beyond the often repeated supply sided strategies. As evident from the experience of Andhra Pradesh, the demand side and governance factors play an equally, if not more, important role in addressing the sustainability issues. So far the experiences are that large investments in water sector would not automatically lead to increase in coverage. The sector also needs a sound policy and capacity so that money is spent effectively and leads to increased water security. The policy should also address resource sustainability and behavioural change goals instead of relying upon a one-sided target driven approach. These aspects are highlighted in the proposed guidelines and their effective implementation needs to be ensured.slippage, India, supply side strategies, policy

Composition of primary cosmic rays near the knee

The size dependence of high energy muons and the size spectrum obtained in the air shower experiment suggest that the mean mass of cosmic rays remains nearly constant at approx 15 up to 5 x 1000,000 GeV and becomes one beyond. The composition model in which nuclei are removed spectrum steepens at 6.7 x 10 power GeV due to leakage from the galaxy, which explains the data which are consistent with data from other experiments

Dynamic response of exchange bias in graphene nanoribbons

The dynamics of magnetic hysteresis, including the training effect and the field sweep rate dependence of the exchange bias, is experimentally investigated in exchange-coupled potassium split graphene nanoribbons (GNRs). We find that, at low field sweep rate, the pronounced absolute training effect is present over a large number of cycles. This is reflected in a gradual decrease of the exchange bias with the sequential field cycling. However, at high field sweep rate above 0.5 T/min, the training effect is not prominent. With the increase in field sweep rate, the average value of exchange bias field grows and is found to follow power law behavior. The response of the exchange bias field to the field sweep rate variation is linked to the difference in the time it takes to perform a hysteresis loop measurement compared with the relaxation time of the anti-ferromagnetically aligned spins. The present results may broaden our current understanding of magnetism of GNRs and would be helpful in establishing the GNRs based spintronic devices.Comment: Accepted Applied Physics Letters (In press