Evolution of an atmospheric boundary layer at a tropical semi-arid station, Anand during boreal summer month of May - A case study

The evolution of an Atmospheric Boundary Layer (ABL) over a semi-arid land station, Anand, (22°35â²N, 72°55â²E, 45.1 m asl) in India, during the summer month of May, is examined using surface meteorological and radiosonde temperature and humidity data collected during LASPEX-97 for a 5-day period from 13-17 May 1997. These 5 days remained undisturbed, and clear sky weather conditions prevailed. However, the data obtained on these days are helpful in understanding the diurnal variation of the ABL over a land station. There are 5 observations per day at an interval of 3 h beginning with 0530 IST. The 0530 IST ascents are chosen to find out the initial ABL heights which exhibit the nocturnal cooling conditions. It is observed from the analysis of θv, θe, θes, q, and P profiles that the nocturnal boundary layer is stable with an inversion close to the ground. The top of an inversion layer is characterized by a θe minimum and a θes maximum. After dawn, the ABL grows to a height of 827 m at 0830 IST. Aloft, a residual layer up to 3200 m is observed. The daytime strong insolation causes formation of an unstable boundary layer close to the ground at 1130 IST with an elevated stable layer between 550 and 930 m. It is only by 1430 IST that the stable layer gets completely wiped out and a convective mixed layer develops up to a height of 3280 m. Lack of moisture inhibits formation of clouds. Hence the ABL at a semi-arid station like Anand is stable in the morning with residual layer aloft and develops into a dry convective boundary layer in the afternoon and evening. Growth of the convective boundary layer (CBL) is observed to be very rapid as it reaches a height up to 3280 m by the afternoon

Molecular Gas, Dust and Star Formation in Galaxies: II. Dust properties and scalings in \sim\ 1600 nearby galaxies

We aim to characterize the relationship between dust properties. We also aim to provide equations to estimate accurate dust properties from limited observational datasets. We assemble a sample of 1,630 nearby (z<0.1) galaxies-over a large range of Mstar, SFR - with multi-wavelength observations available from wise, iras, planck and/or SCUBA. The characterization of dust emission comes from SED fitting using Draine & Li dust models, which we parametrize using two components (warm and cold ). The subsample of these galaxies with global measurements of CO and/or HI are used to explore the molecular and/or atomic gas content of the galaxies. The total Lir, Mdust and dust temperature of the cold component (Tc) form a plane that we refer to as the dust plane. A galaxy's sSFR drives its position on the dust plane: starburst galaxies show higher Lir, Mdust and Tc compared to Main Sequence and passive galaxies. Starburst galaxies also show higher specific Mdust (Mdust/Mstar) and specific Mgas (Mgas/Mstar). The Mdust is more closely correlated with the total Mgas (atomic plus molecular) than with the individual components. Our multi wavelength data allows us to define several equations to estimate Lir, Mdust and Tc from one or two monochromatic luminosities in the infrared and/or sub-millimeter. We estimate the dust mass and infrared luminosity from a single monochromatic luminosity within the R-J tail of the dust emission, with errors of 0.12 and 0.20dex, respectively. These errors are reduced to 0.05 and 0.10 dex, respectively, if the Tc is used. The Mdust is correlated with the total Mism (Mism \propto Mdust^0.7). For galaxies with Mstar 8.5<log(Mstar/Msun) < 11.9, the conversion factor \alpha_850mum shows a large scatter (rms=0.29dex). The SF mode of a galaxy shows a correlation with both the Mgass and Mdust: high Mdust/Mstar galaxies are gas-rich and show the highest SFRs.Comment: 24 pages, 28 figures, 6 tables, Accepted for publication in A&

Dynamical excitation of space-time modes of compact objects

We discuss, in the perturbative regime, the scattering of Gaussian pulses of odd-parity gravitational radiation off a non-rotating relativistic star and a Schwarzschild Black Hole. We focus on the excitation of the $w$-modes of the star as a function of the width $b$ of the pulse and we contrast it with the outcome of a Schwarzschild Black Hole of the same mass. For sufficiently narrow values of $b$, the waveforms are dominated by characteristic space-time modes. On the other hand, for sufficiently large values of $b$ the backscattered signal is dominated by the tail of the Regge-Wheeler potential, the quasi-normal modes are not excited and the nature of the central object cannot be established. We view this work as a useful contribution to the comparison between perturbative results and forthcoming $w$-mode 3D-nonlinear numerical simulation.Comment: RevTeX, 9 pages, 7 figures, Published in Phys. Rev.

Reduced Hamiltonian for next-to-leading order Spin-Squared Dynamics of General Compact Binaries

Within the post Newtonian framework the fully reduced Hamiltonian (i.e., with eliminated spin supplementary condition) for the next-to-leading order spin-squared dynamics of general compact binaries is presented. The Hamiltonian is applicable to the spin dynamics of all kinds of binaries with self-gravitating components like black holes and/or neutron stars taking into account spin-induced quadrupolar deformation effects in second post-Newtonian order perturbation theory of Einstein's field equations. The corresponding equations of motion for spin, position and momentum variables are given in terms of canonical Poisson brackets. Comparison with a nonreduced potential calculated within the Effective Field Theory approach is made.Comment: 11 pages, minor changes to match published version at CQ

Effect of sowing dates and varieties on soybean performance in Vidarbha region of Maharashtra, India

oybean production is widely fluctuating in response to agro-environmental conditions year to year in Vidarbha region. Weather variations are the major determinants of soybean growth and yield. It is also important to study the response of suitable soybean varieties to varying weather parameters. So a field investigation was carried out to study the crop weather relationship of soybean and to optimize the sowing date with different soybean varie-ties. The results revealed that soybean crop sown up to 27th MW accumulated higher growing degree days (1640.5 0C day), photothermal units (20498.1 0C day hour) and recorded significantly higher seed yield (839 kg ha-1) and biological yield (2773 kg ha-1) with maximum heat use efficiency (0.51 kg ha-1°C day-1) and water productivity (2.49 kg ha-mm-1). Later sowings i.e. 30th MW sowing caused decreased amount of rainfall and increased maximum temperature regime across the total growing period with consequently lower seed yield (530 kg ha-1), GDD (1539.2 0C day), PTU (18689.9 0C day hour), heat use efficiency (0.34kg ha-1 °Cday-1) and water productivity (2.05kg ha-mm-1). Soybean variety TAMS 98-21 recorded significantly higher seed yield (734 kg ha-1) and highest biological yield (2649 kg ha-1) with maximum heat use efficiency (0.44 kg ha-1 °C day-1), GDD (1650.5 0C day ) and water productivity (2.41 kg ha-mm-1). Thus, the results of this study illustrated the importance of early sowing with suitable variety of soybean and indicates that sowing upto 27th MW with variety TAMS 98-21 is optimum for maximizing the yield in the Akola region of Vidarbha

Enhancing Big Data Security with Collaborative Intrusion Detection

As an asset of Cloud computing, big data is now changing our business models and applications. Rich information residing in big data is driving business decision making to be a data-driven process. Its security and privacy, however, have always been a concern of the owners of the data. The security and privacy could be strengthened via securing Cloud computing environments. This requires a comprehensive security solution from attack prevention to attack detection. Intrusion Detection Systems (IDSs) are playing an increasingly important role within the realm of a set of network security schemes. In this article, we study the vulnerabilities in Cloud computing and propose a collaborative IDS framework to enhance the security and privacy of big data

Strong clustering of non-interacting, passive sliders driven by a Kardar-Parisi-Zhang surface

We study the clustering of passive, non-interacting particles moving under the influence of a fluctuating field and random noise, in one dimension. The fluctuating field in our case is provided by a surface governed by the Kardar-Parisi-Zhang (KPZ) equation and the sliding particles follow the local surface slope. As the KPZ equation can be mapped to the noisy Burgers equation, the problem translates to that of passive scalars in a Burgers fluid. We study the case of particles moving in the same direction as the surface, equivalent to advection in fluid language. Monte-Carlo simulations on a discrete lattice model reveal extreme clustering of the passive particles. The resulting Strong Clustering State is defined using the scaling properties of the two point density-density correlation function. Our simulations show that the state is robust against changing the ratio of update speeds of the surface and particles. In the equilibrium limit of a stationary surface and finite noise, one obtains the Sinai model for random walkers on a random landscape. In this limit, we obtain analytic results which allow closed form expressions to be found for the quantities of interest. Surprisingly, these results for the equilibrium problem show good agreement with the results in the non-equilibrium regime.Comment: 14 pages, 9 figure