Mud-packing frog: A novel breeding behaviour and parental care in a stream dwelling new species of Nyctibatrachus (Amphibia, Anura, Nyctibatrachidae)

Reproductive modes are diverse and unique in anurans. Selective pressures of evolution, ecology and environment are attributed to such diverse reproductive modes. Globally forty different reproductive modes in anurans have been described to date. The genus Nyctibatrachus has been recently revised and belongs to an ancient lineage of frog families in the Western Ghats of India. Species of this genus are known to exhibit mountain associated clade endemism and novel breeding behaviours. The purpose of this study is to present unique reproductive behaviour, oviposition and parental care in a new species Nyctibatrachus kumbara sp. nov. which is described in the paper. Nyctibatrachus kumbara sp. nov. is a medium sized stream dwelling frog. It is distinct from the congeners based on a suite of morphological characters and substantially divergent in DNA sequences of the mitochondrial 16S rRNA gene. Males exhibit parental care by mud packing the egg clutch. Such parental care has so far not been described from any other frog species worldwide. Besides this, we emphasize that three co-occurring congeneric species of Nyctibatrachus, namely N. jog, N. kempholeyensis and Nyctibatrachus kumbara sp. nov. from the study site differ in breeding behaviour, which could represent a case of reproductive character displacement. These three species are distinct in their size, call pattern, reproductive behaviour, maximum number of eggs in a clutch, oviposition and parental care, which was evident from the statistical analysis. The study throws light on the reproductive behaviour of Nyctibatrachus kumbara sp. nov. and associated species to understand the evolution and adaptation of reproductive modes of anurans in general, and Nyctibatrachus in particular from the Western Ghats.

Multimodal shape oscillations of droplets excited by an air stream

The shape dynamics of droplets exposed to an air jet at intermediate droplet Reynolds numbers is investigated. High speed imaging and hot-wire anemometry are employed to examine the mechanism of droplet oscillation. The theory that the vortex shedding behind the droplet induces oscillation is examined. In these experiments, no particular dominant frequency is found in the wake region of the droplet. Hence the inherent free-stream disturbances prove to be driving the droplet oscillations. The modes of droplet oscillation show a band of dominant frequencies near the corresponding natural frequency, further proving that there is no particular forcing frequency involved. In the frequency spectrum of the lowest mode of oscillation for glycerol at the highest Reynolds number, no response is observed below the threshold frequency corresponding to the viscous dissipation time scale. This selective suppression of lower frequencies in the case of glycerol is corroborated by scaling arguments. The influence of surface tension on the droplet oscillation is studied using ethanol as a test fluid. Since a lower surface tension reduces the natural frequency, ethanol shows lower excited frequencies. The oscillation levels of different fluids are quantified using the droplet aspect ratio and correlated in terms of Weber number and Ohnesorge number. (C) 2014 Elsevier Ltd. All rights reserved.

Frequency Domain Based Solution for Certain Class of Wave Equations: An exhaustive study of Numerical Solutions

The paper discusses the frequency domain based solution for a certain class of wave equations such as: a second order partial differential equation in one variable with constant and varying coefficients (Cantilever beam) and a coupled second order partial differential equation in two variables with constant and varying coefficients (Timoshenko beam). The exact solution of the Cantilever beam with uniform and varying cross-section and the Timoshenko beam with uniform cross-section is available. However, the exact solution for Timoshenko beam with varying cross-section is not available. Laplace spectral methods are used to solve these problems exactly in frequency domain. The numerical solution in frequency domain is done by discretisation in space by approximating the unknown function using spectral functions like Chebyshev polynomials, Legendre polynomials and also Normal polynomials. Different numerical methods such as Galerkin Method, Petrov- Galerkin method, Method of moments and Collocation method or the Pseudo-spectral method in frequency domain are studied and compared with the available exact solution. An approximate solution is also obtained for the Timoshenko beam with varying cross-section using Laplace Spectral Element Method (LSEM). The group speeds are computed exactly for the Cantilever beam and Timoshenko beam with uniform cross-section and is compared with the group speeds obtained numerically. The shear mode and the bending modes of the Timoshenko beam with uniform cross-section are separated numerically by applying a modulated pulse as the shear force and the corresponding group speeds for varying taper parameter in are obtained numerically by varying the frequency of the input pulse. An approximate expression for calculating group speeds corresponding to the shear mode and the bending mode, and also the cut-off frequency is obtained. Finally, we show that the cut-off frequency disappears for large in, for epsilon > 0 and increases for large in, for epsilon < 0.

Overview of nano-drugs characteristics for clinical application: the journey from the entry to the exit point

The ever-increasing number of diseases worldwide requires comprehensive, efficient, and cost-effective modes of treatments. Among various strategies, nanomaterials fulfill most of these criteria. The unique physicochemical properties of nanoparticles have made them a premier choice as a drug or a drug delivery system for the purpose of treatment, and as bio-detectors for disease prognosis. However, the main challenge is the proper consideration of the physical properties of these nanomaterials, while developing them as potential tools for therapeutics and/or diagnostics. In this review, we focus mainly on the characteristics of nanoparticles to develop an effective and sensitive system for clinical purposes. This review will present an overview of the important properties of nanoparticles, through their journey from its route of administration until disposal from the human body after accomplishing targeted functionality. We have chosen cancer as our model disease to explain the potentiality of nano-systems for therapeutics and diagnostics in relation to several organs (intestine, lung, brain, etc.). Furthermore, we have discussed their biodegradability and accumulation probability which can cause unfavorable side effects in healthy human subjects.

Oscillation dynamics of sessile droplets subjected to substrate vibration

Sessile droplets on a vibrating substrate are investigated focusing on axisymmetric oscillations with pinned contact line. Proper orthogonal decomposition is employed to identify the different modes of droplet shape oscillation and quantitatively assess the droplet oscillation and spectral response. We offer the first experimental evidence for the analogy of an oscillating sessile droplet with a non-linear spring mass damper system. The qualitative and quantitative agreement of amplitude response and phase response curves and limit cycles of the model dynamical system with that observed experimentally suggest that the bulk oscillations in the fundamental mode of a sessile droplet can be very well modeled by a Duffing oscillator with a hard spring, especially near the resonance. The red shift of the resonance peak with an increase in the glycerol concentration is clearly evidenced by both the experimental and predicted amplitude response curves. The influence of various operational parameters such as excitation frequency and amplitude and fluid properties on the droplet oscillation characteristics is adequately captured by the model. (C) 2014 Elsevier Ltd. All rights reserved.

Study Of Lattice Dynamics In Yttrium Doped NdMnO3 Using Raman Spectroscopy

A systematic study of Raman spectra on Yttrium doped NdMnO3 polycrystalline samples was undertaken to understand the lattice dynamics in this compound. Raman active phonons were analyzed and the observed peak were assigned to elucidate various phonon modes in the range (200 - 800) cm(-1). It was observed that at 325 cm(-1) phonon frequency shifts upward as much as upto 4 % with increase in Yttrium content. Lattice distortions manifest themselves by frequency shifts in both bending and tilt modes of MnO6 octahedra, resulting in increase of Raman band line-widths.

Hybrid and Rogue Kinases Encoded in the Genomes of Model Eukaryotes

The highly modular nature of protein kinases generates diverse functional roles mediated by evolutionary events such as domain recombination, insertion and deletion of domains. Usually domain architecture of a kinase is related to the subfamily to which the kinase catalytic domain belongs. However outlier kinases with unusual domain architectures serve in the expansion of the functional space of the protein kinase family. For example, Src kinases are made-up of SH2 and SH3 domains in addition to the kinase catalytic domain. A kinase which lacks these two domains but retains sequence characteristics within the kinase catalytic domain is an outlier that is likely to have modes of regulation different from classical src kinases. This study defines two types of outlier kinases: hybrids and rogues depending on the nature of domain recombination. Hybrid kinases are those where the catalytic kinase domain belongs to a kinase subfamily but the domain architecture is typical of another kinase subfamily. Rogue kinases are those with kinase catalytic domain characteristic of a kinase subfamily but the domain architecture is typical of neither that subfamily nor any other kinase subfamily. This report provides a consolidated set of such hybrid and rogue kinases gleaned from six eukaryotic genomes-S. cerevisiae, D. melanogaster, C. elegans, M. musculus, T. rubripes and H. sapiens-and discusses their functions. The presence of such kinases necessitates a revisiting of the classification scheme of the protein kinase family using full length sequences apart from classical classification using solely the sequences of kinase catalytic domains. The study of these kinases provides a good insight in engineering signalling pathways for a desired output. Lastly, identification of hybrids and rogues in pathogenic protozoa such as P. falciparum sheds light on possible strategies in host-pathogen interactions.

Observation of magnetically hard grain boundaries in double-perovskite Sr2FeMoO6

Unusual low-temperature magneto-resistance (MR) of ferromagnetic Sr2FeMoO6 polycrystals has been attributed to magnetically hard grain boundaries which act as spin valves. We detected the different magnetic hysteresis curves for the grains and the grain boundaries of polycrystalline Sr2FeMoO6 by utilizing the different probing depths of the different detection modes of x-ray absorption spectroscopy (XAS) and x-ray magnetic circular dichroism (XMCD), namely, the total electron yield (TEY) mode (probing depth similar to 5 nm) and the total fluorescence yield (TFY) mode (probing depth similar to 100 nm). At 20 K, the magnetic coercivity detected in the TEY mode (H-c,H- TEY) was several times larger than that in the TFY mode (H-c,H- TFY), indicating harder ferromagnetism of the grain boundaries than that of the grains. At room temperature, the grain boundary magnetism became soft and H-c,H- TEY and H-c,H- TFY were nearly the same. From the line-shape analysis of the XAS and XMCD spectra, we found that in the grain boundary region the ferromagnetic component is dominated by Fe2+ or well-screened signals, while the non-magnetic component is dominated by Fe3+ or poorly screened signals. Copyright (C) EPLA, 2014

Collective eigenstates of emission in an N-entity heterostructure and the evaluation of its Green tensors and self-energy components

Optical emission from emitters strongly interacting among themselves and also with other polarizable matter in close proximity has been approximated by emission from independent emitters. This is primarily due to our inability to evaluate the self-energy matrices and radiative properties of the collective eigenstates of emitters in heterogeneous ensembles. A method to evaluate self-energy matrices that is not limited by the geometry and material composition is presented to understand and exploit such collective excitations. Numerical evaluations using this method are used to highlight the significant differences between independent and the collective modes of emission in nanoscale heterostructures. A set of N Lorentz emitters and other polarizable entities is used to represent the coupled system of a generalized geometry in a volume integral approach. Closed form relations between the Green tensors of entity pairs in free space and their correspondents in a heterostructure are derived concisely. This is made possible for general geometries because the global matrices consisting of all free-space Green dyads are subject to conservation laws. The self-energy matrix can then be assembled using the evaluated Green tensors of the heterostructure, but a decomposition of its components into their radiative and nonradiative decay contributions is nontrivial. The relations to compute the observables of the eigenstates (such as quantum efficiency, power/energy of emission, radiative and nonradiative decay rates) are presented. A note on extension of this method to collective excitations, which also includes strong interactions with a surface in the near-field, is added. (C) 2014 Optical Society of America

Influence of dynamic operating conditions on the performance of metal hydride based solid sorption cooling systems

The performance of metal hydride based solid sorption cooling systems depends on the driving pressure differential, and the rate of hydrogen transfer between coupled metal hydride beds during cooling and regeneration processes. Conventionally, the mid-plateau pressure difference obtained from `static' equilibrium PCT data are used for the thermodynamic analysis. It is well known that the processes are `dynamic' because the pressure and temperature, and hence the concentration of the hydride beds, are continuously changing. Keeping this in mind, the pair of La0.9Ce0.1Ni5 - LaNi4.7Al0.3 metal hydrides suitable for solid sorption cooling systems were characterised using both static and dynamic methods. It was found that the PCT characteristics, and the resulting enthalpy (Delta H) and entropy (Delta S) values, were significantly different for static and dynamic modes of measurements. In the present study, the solid sorption metal hydride cooling system is analysed taking in to account the actual variation in the pressure difference (Delta P) and the dynamic enthalpy values. Compared to `static' property based analysis, significant decrease in the driving potentials and transferrable amounts of hydrogen, leading to decrease in cooling capacity by 57.8% and coefficient of performance by 31.9% are observed when dynamic PCT data at the flow rate of 80 ml/min are considered. Copyright 2014 (C) Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

``Conformational Simulation'' of Sulfamethizole by Molecular Complexation and Insights from Charge Density Analysis: Role of Intramolecular S center dot center dot center dot O Chalcogen Bonding

Intramolecular S center dot center dot center dot O chalcogen bonding and its potential to lock molecular conformation have been examined in the crystal forms of sulfamethizole, a sulfonamide antibiotic. Molecular complexes of sulfamethizole, including salts and cocrystal, have been synthesized, and their crystal structures were analyzed in order to examine the possible conformational preferences of the molecule in various ionic states and supramolecular environments (neutral/cocrystal, anionic salt, and cationic salt forms). The electrostatic potential mapped on Hirshfeld surfaces generated for these crystal forms provides insights into the possible binding modes of the drug in different environments. Further, the observed conformation locking feature has been rationalized in terms of the experimental charge density features of the intramolecular S center dot center dot O chalcogen bonding in sulfamethizole. The study quantitatively illustrates and rationalizes an intriguing case of a local minimum of molecular conformation being exclusively preferred over the global minimum, as it facilitates more efficient intermolecular interactions in a supramolecular environment.

Decreasing intensity of monsoon low-frequency intraseasonal variability over India

Understanding the changing nature of the intraseasonal oscillatory (ISO) modes of Indian summer monsoon manifested by active and break phase, and their association with extreme rainfall events are necessary for probabilistic estimation of flood-related risks in a warming climate. Here, using ground-based observed rainfall, we define an index to measure the strength of monsoon ISOs and show that the relative strength of the northward-propagating low-frequency ISO (20-60 days) modes have had a significant decreasing trend during the past six decades, possibly attributed to the weakening of large-scale circulation in the region during monsoon season. This reduction is compensated by a gain in synoptic-scale (3-9 days) variability. The decrease in low-frequency ISO variability is associated with a significant decreasing trend in the percentage of extreme events during the active phase of the monsoon. However, this decrease is balanced by significant increasing trends in the percentage of extreme events in the break and transition phases. We also find a significant rise in the occurrence of extremes during early and late monsoon months, mainly over eastern coastal regions. Our study highlights the redistribution of rainfall intensity among periodic (low-frequency) and non-periodic (extreme) modes in a changing climate scenario.

A hidden symmetry of AdS resonances

Recent investigations have revealed powerful selection rules for resonant energy transfer between modes of nonlinear perturbations in global anti-de Sitter (AdS) space-time. It is likely that these selection rules are due to the highly symmetric nature of the underlying AdS background, though the precise relation has remained unclear. In this article, we demonstrate that the equation satisfied by the scalar field mode functions in AdS(d+1) has a hidden SU(d) symmetry, and explicitly specify the multiplets of this SU(d) symmetry furnished by the mode functions. We also comment on the role this structure might play in explaining the selection rules.

Effect of Particle Concentration on Shape Deformation and Secondary Atomization Characteristics of a Burning Nanotitania Dispersion Droplet

Secondary atomization characteristics of burning bicomponent (ethanol-water) droplets containing titania nanoparticles (NPs) in dilute (0.5% and 1 wt.%) and dense concentrations (5% and 7.5 wt.%) are studied experimentally at atmospheric pressure under normal gravity. It is observed that both types of nanofuel droplets undergo distinct modes of secondary breakup, which are primarily responsible for transporting particles from the droplet domain to the flame zone. For dilute nanosuspensions, disruptive response is characterized by low intensity atomization modes that cause small-scale localized flame distortion. In contrast, the disruption behavior at dense concentrations is governed by high intensity bubble ejections, which result in severe disruption of the flame envelope.

Organic alloys of room temperature liquids thiophenol and selenophenol

The first examples of organic alloys of two room temperature liquids, obtained and characterized via in situ cryo-crystallography, are presented. Thiophenol and selenophenol, which exhibit isostructurality and similar modes of S center dot center dot center dot S and Se center dot center dot center dot Se homo-chalcogen interactions along with weak and rare S-H center dot center dot center dot S and Se-H center dot center dot center dot Se hydrogen bonds, are shown to form solid solutions exhibiting Veggard's law-like trends.