Simultaneously Sparse Solutions to Linear Inverse Problems with Multiple System Matrices and a Single Observation Vector

A linear inverse problem is proposed that requires the determination of multiple unknown signal vectors. Each unknown vector passes through a different system matrix and the results are added to yield a single observation vector. Given the matrices and lone observation, the objective is to find a simultaneously sparse set of unknown vectors that solves the system. We will refer to this as the multiple-system single-output (MSSO) simultaneous sparsity problem. This manuscript contrasts the MSSO problem with other simultaneous sparsity problems and conducts a thorough initial exploration of algorithms with which to solve it. Seven algorithms are formulated that approximately solve this NP-Hard problem. Three greedy techniques are developed (matching pursuit, orthogonal matching pursuit, and least squares matching pursuit) along with four methods based on a convex relaxation (iteratively reweighted least squares, two forms of iterative shrinkage, and formulation as a second-order cone program). The algorithms are evaluated across three experiments: the first and second involve sparsity profile recovery in noiseless and noisy scenarios, respectively, while the third deals with magnetic resonance imaging radio-frequency excitation pulse design.Comment: 36 pages; manuscript unchanged from July 21, 2008, except for updated references; content appears in September 2008 PhD thesi

ESTIMATION OF POTENTIAL EVAPOTRANSPIRATION WITH HARGREAVES-SAMANI MODEL AT VARIOUS LOCATIONS IN PUERTO RICO

ESTIMATION OF POTENTIAL EVAPOTRANSPIRATION WITH HARGREAVES-SAMANI MODEL AT VARIOUS LOCATIONS IN PUERTO RIC

Role of dual biomarkers and uterine artery doppler study in predicting PIH and IUGR in antenatal patients registered in a tertiary care centre

Background: The incidence of IUGR is between 3 to 7%, whereas that of Hypertensive disorders of pregnancy is about 10% of pregnant women around the world. These conditions are associated with a high rate of perinatal morbidity and mortality, posing a need for the detection of the potential causes of maternal and foetal morbidity and mortality and for the prediction of these conditions early during pregnancy.Methods: Patients with first antenatal visit before 10 weeks gestation underwent routine NT scan between 11–13 weeks with bilateral UAD-RI of the maternal uterine arteries. The placental volume was assessed. Serum dual biomarker test (β hCG and PAPP-A) was performed after this scan and analysed as multiples of median (MoM). Blood pressure was recorded at every ANC visit till 2 weeks after delivery. Neonatal head and chest circumference, birth length and weight were recorded.Results: The mean values of PAPP-A levels of Non-PIH and PIH groups were 1.32±0.91 MoM and 0.68±0.39 MoM respectively, showing statistically significant difference.  The serum PAPP-A levels showed statistically significant difference between Non-IUGR and IUGR groups (1.24±0.87 MoM and 0.46±0.20 MoM respectively).Conclusions: In our study, PAPP-A level is observed as a good indicator for possible prediction of PIH and IUGR whereas levels of β hCG and UAD-RI were not good predictors. The role of Placental volume in prediction of IUGR needs to be explored further with larger sample size. Future studies are needed with a larger group with inclusion of measurement of PI values

Land Surface Characterization for Identification and Assessment of Potential Grazing Lands in Arid Western Rajasthan, India

Grazing lands (non-arable terrestrial ecosystems) play a vital role in the rural economy and environmental conservation. Modern tools in which, GIS, GPS and satellite remote sensing play vital role in the assessment, characterization and management of grazinglands (Paul et al., 2010). The present study aims to assess the physical conditions and distribution pattern of permanent pastures and other grazing lands in arid Rajasthan using remote sensing and GIS techniques. Though grazing lands do occur in a number of habitats, the study has focused on those sites which have water resources for its rational utilization for pasture/grassland development. Rapid advances in the areas of Remote Sensing, Earth Observations systems, data processing techniques and applications have facilitated users for a better understanding of terrain. One of the recent trends in remote sensing is its application in the extraction of terrain related parameters using large scale mapping and DEM generation. GIS and IRS data are used in inventory, assessment, characterization and management of grazinglands and estimation of forage production & supply-demand balance sheets (Singh et al., 1997)

Social protection for all ages? Impacts of Ethiopia's Productive Safety Net Program on child nutrition

We investigate the impact of a large-scale social protection scheme, the Productive Safety Net Program (PSNP) in Ethiopia, on child nutritional outcomes. Children living in households that receive cash transfers should experience improved child nutrition. However, in the case of the PSNP, which for the majority of participants is a public works program, there are several potential threats to finding effects: first, without conditionality on child inputs, increased household income may not be translated into improved child nutrition. Second, the work requirement may impact on parental time, child time use and calories burned. Third, if there is a critical period for child human capital investment that closes before the age of 5 then children above this age may not see any improvement in medium-term nutritional outcomes, measured here as height-for-age. Using a cohort study that collected data both pre-and post-program implementation in 2002, 2006 and 2009, we exploit several novel aspects of the survey design to find estimates that can deal with non-random program placement. We present both matching and difference-in-differences estimates for the index children, as well as sibling-differences. Our estimates show an important positive medium-term nutritional impact of the program for children aged 5-15 that are comparable in size to Conditional Cash Transfer program impacts for much younger children. We show indicative evidence that the program impact on improved nutrition is associated with improved food security and reduced child working hours. Our robustness checks restrict the comparison group, by including only households who were shortlisted, but never received PSNP, and also exclude those who never received aid, thus identifying impact based on timing alone. We cannot rule out that the nutritional impact of the program is the same for younger and older children. © 2016 Elsevier Ltd

Evolution of Coordination in Social Networks: A Numerical Study

Coordination games are important to explain efficient and desirable social behavior. Here we study these games by extensive numerical simulation on networked social structures using an evolutionary approach. We show that local network effects may promote selection of efficient equilibria in both pure and general coordination games and may explain social polarization. These results are put into perspective with respect to known theoretical results. The main insight we obtain is that clustering, and especially community structure in social networks has a positive role in promoting socially efficient outcomes.Comment: preprint submitted to IJMP

Young stellar population and ongoing star formation in the HII complex Sh2-252

In this paper an extensive survey of the star forming complex Sh2-252 has been undertaken with an aim to explore its hidden young stellar population as well as to understand the structure and star formation history. This complex is composed of five embedded clusters associated with the sub-regions A, C, E, NGC 2175s and Teu 136. Using 2MASS-NIR and Spitzer-IRAC, MIPS photometry we identified 577 young stellar objects (YSOs), of which, 163 are Class I, 400 are Class II and 14 are transition disk YSOs. Spatial distribution of the candidate YSOs shows that they are mostly clustered around the sub-regions in the western half of the complex, suggesting enhanced star formation activity towards its west. Using the spectral energy distribution and optical colour-magnitude diagram based age analyses, we derived probable evolutionary status of the sub-regions of Sh2-252. Our analysis shows that the region A is the youngest (~ 0.5 Myr), the regions B, C and E are of similar evolutionary stage (~ 1-2 Myr) and the clusters NGC 2175s and Teu 136 are slightly evolved (~ 2-3 Myr). Morphology of the region in the 1.1 mm map shows a semi-circular shaped molecular shell composed of several clumps and YSOs bordering the western ionization front of Sh2-252. Our analyses suggest that next generation star formation is currently under way along this border and that possibly fragmentation of the matter collected during the expansion of the HII region as one of the major processes responsible for such stars. We observed the densest concentration of YSOs (mostly Class I, ~ 0.5 Myr) at the western outskirts of the complex, within a molecular clump associated with water and methanol masers and we suggest that it is indeed a site of cluster formation at a very early evolutionary stage, sandwiched between the two relatively evolved CHII regions A and B.Comment: 19 pages, 13 figures, Accepted for publication in MNRA

Little Higgs model effects in γγ→γγ\gamma \gamma \to \gamma \gamma

Though the predictions of the Standard Model (SM) are in excellent agreement with experiments there are still several theoretical problems associated with the Higgs sector of the SM, where it is widely believed that some ``{\it new physics}'' will take over at the TeV scale. One beyond the SM theory which resolves these problems is the Little Higgs (LH) model. In this work we have investigated the effects of the LH model on \gggg scattering \cite{Choudhury:2006xa}.Comment: Talk given at LCWS06, Bangalore, 4 pages (style files included