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We present molecular-frame measurements of the recombination dipole matrix element (RDME) in CO2, N2O, and carbonyl sulfide (OCS) molecules using high-harmonic spectroscopy. Both the amplitudes and phases of the RDMEs exhibit clear imprints of a two-center interference minimum, which moves in energy with the molecular alignment angle relative to the laser polarization. We find that whereas the angle dependence of this minimum is consistent with the molecular geometry in CO2 and N2O, it behaves very differently in OCS; in particular, the phase shift which accompanies the two-center minimum changes sign for different alignment angles. Our results suggest that two interfering structural features contribute to the OCS RDME, namely, (i) the geometrical two-center minimum and (ii) a Cooper-like, electronic-structure minimum associated with the sulfur end of the molecule. We compare our results to ab initio calculations using time-dependent density functional theory and present an empirical model that captures both the two-center and the Cooper-like interferences. We also show that the yield from unaligned samples of two-center molecules is, in general, reduced at high photon energies compared to aligned samples, due to the destructive interference between molecules with different alignments. [ABSTRACT FROM AUTHOR]

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.ydbio.2009.12.027 Byline: G. Abello (a), S. Khatri (a), M. Radosevic (a), P.J. Scotting (b), F. Giraldez (a), B. Alsina (a) Keywords: Otic placode; SoxB1; FGF; BMP; AP patterning; Neural fate; Ectodermal signaling Abstract: The development of neural tissue starts with the activation of early neural genes such as the SoxB1 transcription factors, which are expressed in response to signaling molecules. Neural progenitors in the inner ear are only generated in the anterior placodal domain, but the mechanisms that determine when and how otic neural fate is acquired are still unknown. Here, we show that Sox3 expression becomes restricted to the anterior territory of the chick otic field and that misexpression of Sox3 induces Sox2 and Delta1 in the non-neurogenic otic territory. This suggests that Sox3 plays a central role in the establishment of an otic neural fate. Furthermore, Sox3 down-regulates the expression of Lmx1b, a marker of the posterior non-neurogenic otic epithelium. The expression of Sox3 is maintained by the positive action of FGF8 derived from the otic ectoderm. On the contrary, BMP signaling does not have a major influence on neural commitment but instead regulates Lmx1b expression in the otic placode. Together, the data support the notion that Sox3 is critical for the development of the neural elements of the inner ear, and they highlight the importance of localized signaling from the ectoderm in establishing the neurogenic vs. non-neurogenic anteroposterior asymmetry that characterizes the early otic placode. Author Affiliation: (a) Developmental Biology Group, DCEXS-Universitat Pompeu Fabra, PRBB, Dr. Aiguader 88, 08003 Barcelona, Spain (b) Children's Brain Tumour Research Centre, Institute of Genetics, University of Nottingham, QMC, Nottingham, NG7 2UH, UK Article History: Received 16 July 2009; Revised 30 November 2009; Accepted 18 December 2009

Mobile Ad hoc Networks (MANETs) is an infrastructure less and random mobility-based class of wireless networks with seamless possibilities of 'on the fly' communication through self-coordination among autonomous mobile nodes while being in the transmission range of each other. This low cost, easy to deploy, simplicity, and self-organisation of MANET altogether revolutionised wired networks and could connect otherwise unreachable terrains/sites. To handle the severity of colossal issues like dynamic topology, scarce resources and frequent rupturing of established routes in MANETs, conservation of energy becomes inevitable to administer contemporary applications. After an extensive literature survey for provisioning reliability and multicast routing in MANETs, researchers concluded the conservation of mobile nodes energy embrace a very consequential role in extending network life. The PLA (Proposed Local Adjustment) model is based on eliminating flooding, preserving nodes battery life by selectively choosing forwarder node at each hop level, and handling route failures locally, eventually makes the network more robust and resilient. The PLA model when simulated on NS2.35 against AODV on various parameters like control overhead generated, packet delivery ratio, energy conserved index, produced quite convincing and promising results, to be offered to remote and rescue-based applications in the vicinity of infrastructure less regions. [ABSTRACT FROM AUTHOR]

A mobile ad-hoc network (MANET) is a collection of mobile devices having routing capabilities to reach to the destination. Cooperation of all the nodes in the network is essential for efficient performance of the network. But cooperation of all the nodes cannot be assumed in such a dynamic network in which nodes are joining and leaving very frequently and topology changes randomly. Some of the nodes can be compromised that adversely affects the performance of the network. Different types of attacks can be performed at various layers of the protocol suite An Intrusion detection system is required to accurately detect attacks and isolates compromised nodes in the network. In this work black hole attack has been introduced using Ad-hoc On Demand Distance Vector (AODV) as Routing MANET protocol and the system is trained and tested using Support Vector Machine (SVM) to detect the malicious nodes in the network. The simulation was done in NS-2 to carry out black hole attack and trace file obtained is used as dataset for training and testing purpose using R. [ABSTRACT FROM AUTHOR]

A detailed temperature-dependent study of the Raman spectra of oriented single crystals of NH4ClO4 is reported in the spectral regions of lattice modes and internal vibrations of the ClO-4 and NH+4 ions between 10 and 300 K. The internal modes of the ClO-4 ions show splitting into several components due to site and correlation field effects. The linewidth, frequency shift, and intensities of some of the internal modes of the ClO-4 and NH+4 ions and the frequency shift of a few lattice modes show anomalous temperature dependence around 180 and at 40 K. These anomalies have been explained in terms of phase transformations associated with the changes in hydrogen bonding strength and reorientational freedom of the NH+4 ions in the lattice. The low temperature transition at 40 K exhibits a sharp and discontinuous anomaly in some of the spectral parameters measured in this study which is associated with order–disorder-type transition. The measured linewidth of the ν’1 mode in the diagonal scattering configuration can be understood in terms of vibrational dephasing of the ν1 excited state due to vibrational–librational coupling. The estimated activation energies in the 50–160 K and 10–40 K temperature ranges are found to be 141 and 51 cm-1, respectively, which correspond to the observed NH+4 librational frequencies. [ABSTRACT FROM AUTHOR]